Load sensor

Abstract

A load sensor according to the present invention comprises: an element that has a plurality of pressure-sensitive parts that undergo a change in capacitance in response to loads and detects loads on the basis of the capacitance of the plurality of pressure-sensitive parts; and a load distribution plate that is laid over the element and distributes applied loads. Loads applied to the element are distributed by the load distribution plate and applied to the pressure-sensitive parts. As a result, loads applied to the element are detected appropriately even when applied to the element locally.

Description

Load sensor

[0001] The present invention relates to a load sensor that detects an externally applied load based on a change in capacitance.

[0002] Load sensors are widely used in fields such as industrial equipment, robots, and vehicles. In recent years, with the development of computer control technology and the improvement of design, the development of electronic devices that use free-form surfaces such as humanoid robots and automotive interior parts has advanced. Along with this, it is required to attach high-performance load sensors to each free-form surface.

[0003] Patent Document 1 below describes a pressure-sensitive element including a first conductive member (conductive elastomer) made of sheet-like conductive rubber, a linear second conductive member (conductor wire) sandwiched between the first conductive member and a base material, and a dielectric formed so as to cover the second conductive member. Load is detected for each region where the first conductive member and the second conductive member intersect through the dielectric. In this configuration, as the load increases, the contact area between the first conductive member and the dielectric increases, and accordingly, the capacitance between the first conductive member and the second conductive member increases. Therefore, by detecting the value of the capacitance between the first conductive member and the second conductive member, the load applied to the pressure-sensitive element can be detected.

[0004] Patent Document 2 below describes a load sensor having a configuration in which a wire is sandwiched between two base members. A conductor wire is coated with a dielectric to form a wire. On one base member, a conductive elastomer is formed so as to overlap the wire. In this configuration, as the load increases, the contact area between the conductive elastomer and the wire increases, and accordingly, the capacitance between the conductor wire and the conductive elastomer increases. By detecting the value of this capacitance, the load applied to the load sensor can be detected.

[0005] International Publication No. 2018 / 096901 International Publication No. 2021 / 075356

[0006] In the load sensor described in Patent Document 1, multiple conductor wires can be combined with a single conductive elastic body to form a single element. This allows for a large change in the contact area between the conductive elastic body and the conductor wires via the dielectric when a load is applied, enabling accurate detection of the load.

[0007] However, in this configuration, when a load is applied locally to the element, the increase in the contact area decreases or stops altogether. As a result, the rate of increase in capacitance based on the contact area decreases or disappears, which may lead to an inability to properly detect the load.

[0008] The main aspect of the present invention relates to a load sensor. The load sensor according to this aspect comprises an element unit having one or more pressure-sensitive parts whose capacitance changes with load, and which detects load based on the capacitance of the one or more pressure-sensitive parts, and a load-distributing plate superimposed on the element unit to distribute the applied load.

[0009] According to the load sensor of this embodiment, the load applied to the element is distributed by the load distribution plate and applied to the pressure-sensitive part. As a result, even when a load is applied locally to the element, the load applied to the element can be properly detected.

[0010] As described above, the present invention provides a load sensor that can properly detect the load applied to an element even when the load is applied locally to the element.

[0011] In the load sensor described in Patent Document 2, the pressure-sensitive part for detecting load is formed by overlapping conductive elastic bodies and wires. In this configuration, when a localized load is applied at a location away from the pressure-sensitive part, the two base members come into contact at that location, making it difficult for the load to be applied to the pressure-sensitive part.

[0012] In contrast, by placing a load-distributing plate on top of the load-bearing base member, even when a load is applied at a location far from the pressure-sensitive part, this load is distributed by the load-distributing plate and more easily transmitted to the pressure-sensitive part. This allows for the detection of localized loads up to a high load range.

[0013] However, in this configuration, when a load is locally applied to the edge of the load distribution plate, the load distribution plate tilts so that the load application point is lower. As a result, in the range of relatively low loads, the edge of the base member on which the load distribution plate is stacked comes into contact with the other base member, and the rate of increase in the contact area decreases. Therefore, when such a localized high load is applied to the load distribution plate, the detected load value will differ depending on the application point, and it may become impossible to properly detect high loads.

[0014] Another main aspect of the present invention relates to a load sensor. The load sensor according to this embodiment comprises: a sheet-like first base member having elasticity and having a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; and a load distribution plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member. When viewed in plan from the first upper surface to the first lower surface of the first base member, the load distribution plate is divided into a first region and second regions on both sides thereof, the pressure-sensitive part is disposed in the first region, the thickness of the load distribution plate in the second regions on both sides is set to be smaller than the thickness of the load distribution plate in the first region, and the second lower surfaces of the load distribution plate in the second regions on both sides are spaced further from the second base member than the second lower surface of the load distribution plate in the first region.

[0015] According to the load sensor of this embodiment, when a load is applied to any of the second regions, the second region is displaced in the direction of the applied load, causing the load distribution plate to tilt. However, since the second lower surface of the load distribution plate in the second region is spaced further from the second base member than the second lower surface of the load distribution plate in the first region, the second lower surface of the load distribution plate in the second region does not press against the upper surface of the second base member up to a relatively high load range. Therefore, the load applied locally to the load distribution plate can be properly detected up to a relatively high load range.

[0016] As described above, the present invention provides a load sensor capable of appropriately detecting locally applied loads to a load distribution plate up to a relatively high load range.

[0017] A further main aspect of the present invention relates to a load sensor. The load sensor according to this aspect comprises: a sheet-like first base member having elasticity and a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; a load distribution plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member; and a guide that guides the load distribution plate in the vertical direction, when the direction from the second upper surface to the second lower surface and the direction from the second lower surface to the second upper surface of the load distribution plate are defined as the vertical direction, thereby suppressing the tilt of the load distribution plate in at least the vertical direction.

[0018] According to the load sensor of this embodiment, even when a load is locally applied to the end of the load distribution plate, the load distribution plate is guided in the vertical direction, and tilting of the load distribution plate is suppressed, at least in the vertical direction. As a result, the situation in which the first base member is supported by the second base member due to the tilting of the load distribution plate can be avoided, and the detection sensitivity can be maintained at a relatively high load range even when a load is locally applied to the end of the load distribution plate. Therefore, loads locally applied to the load distribution plate can be properly detected up to a relatively high load range.

[0019] As described above, the present invention provides a load sensor capable of appropriately detecting locally applied loads to a load distribution plate up to a relatively high load range.

[0020] The effects and significance of the present invention will become even clearer from the description of the embodiments shown below. However, the embodiments shown below are merely examples of how to implement the present invention, and the present invention is not limited in any way to those described in the embodiments below.

[0021] Figures 1(a) and 1(b) are schematic perspective views showing the structure configuration in the manufacturing process according to Embodiment 1. Figure 2 is a schematic perspective view showing the configuration of multiple load distribution plates, multiple adhesive members, structure, and second base member in the manufacturing process according to Embodiment 1. Figure 3 is a schematic perspective view showing the configuration of the load sensor according to Embodiment 1. Figure 4 is a schematic plan view showing the configuration of the load sensor according to Embodiment 1. Figures 5(a) and 5(b) are schematic diagrams showing the cross-section of the element portion when the load sensor according to Embodiment 1 is cut by a plane parallel to the X-Z plane. Figure 6(a) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Comparative Examples 1 and 2. Figure 6(b) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 1. Figures 7(a) to 7(c) are diagrams showing the deformation of the first base member in the simulation of Comparative Examples 1 and 2 and Embodiment 1. Figure 8 is a graph showing the relationship between load and capacitance in the simulation of Comparative Examples 1 and 2 and Embodiment 1. Figure 9 is a schematic plan view showing the configuration of the load sensor according to Modification Example 1. Figure 10 is a schematic plan view showing the configuration of the load sensor according to Modification Example 2. Figure 11 is a schematic perspective view showing the configuration of multiple load distribution plates, multiple adhesive members, a structure, and a second base member in the manufacturing process according to Modification Example 3. Figure 12 is a schematic plan view showing the configuration of the load sensor according to Modification Example 3. Figures 13(a) and (b) are schematic diagrams showing the cross-section of the element part when the load sensor is cut by a plane parallel to the X-Z plane according to Modification Example 3. Figure 14(a) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Modification Example 3. Figure 14(b) is a diagram showing the deformation of the first base member in the simulation of Modification Example 3. Figure 15 is a graph showing the relationship between load and capacitance in the simulation of Modification Example 3. Figure 16 is a schematic plan view showing the configuration of the load sensor according to Modification Example 4. Figure 17(a) is a schematic perspective view showing the configuration of the load distribution plate according to Modification Example 5. Figure 17(b) is a schematic diagram showing the cross-section of the element portion when the load sensor is cut by a plane parallel to the X-Z plane according to Modification Example 5.Figures 18(a) and 18(b) schematically show the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 6. Figure 19 schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 7. Figure 20 schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Embodiment 2. Figure 21 schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Embodiment 3. Figures 22(a) and 22(b) schematically show the configuration of the structure in the manufacturing process according to Embodiment 4. Figure 23 schematically shows the configuration of a plurality of load distribution plates, a plurality of adhesive members, a structure, and a second base member in the manufacturing process according to Embodiment 4. Figure 24 schematically shows the configuration of the load distribution plate according to Embodiment 4. Figure 25 schematically shows the configuration of the load sensor according to Embodiment 4. Figure 26 is a schematic plan view showing the configuration of the load sensor according to Embodiment 4. Figures 27(a) and (b) are schematic diagrams showing the cross-section of the element portion when the load sensor according to Embodiment 4 is cut by a plane parallel to the X-Z plane. Figure 28(a) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of the comparative example. Figure 28(b) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 4. Figures 29(a) and (b) are diagrams showing the state of the load distribution plate and the first base member in the simulation of the comparative example and Embodiment 4. Figure 30 is a graph showing the relationship between load and capacitance in the simulation of the comparative example and Embodiment 4. Figure 31 is a schematic perspective view showing the configuration of multiple load distribution plates, multiple adhesive members, a structure and a second base member in the manufacturing process according to Modified Example 8. Figure 32 is a schematic perspective view showing the configuration of the load distribution plate according to Modified Example 8. Figure 33 is a schematic plan view showing the configuration of the load sensor according to Modified Example 8. Figures 34(a) and 34(b) schematically show the cross-section of the element portion when the load sensor is cut by a plane parallel to the X-Z plane, according to modification example 8.Figures 35(a) and 35(b) schematically show the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 9. Figures 36(a) and 36(b) schematically show the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 9. Figure 37(a) schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 10. Figure 37(a) schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 11. Figure 38 schematically shows the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to Modification Example 12. Figure 39 is a schematic plan view showing the configuration of the load sensor, according to Modification Example 13. Figure 40 is a schematic diagram showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane according to Embodiment 5. Figure 41 is a schematic diagram showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane according to Embodiment 6. Figures 42(a) and (b) are schematic perspective views showing the configuration of the structure in the manufacturing process according to Embodiment 7. Figure 43 is a schematic perspective view showing the configuration of the structure in the manufacturing process according to Embodiment 7. Figure 44 is a schematic perspective view showing the configuration of a plurality of load distribution plates, a plurality of adhesive members, a structure, and a second base member in the manufacturing process according to Embodiment 7. Figure 45 is a schematic perspective view showing the configuration of the load sensor according to Embodiment 7. Figure 46 is a schematic plan view showing the configuration of the load sensor according to Embodiment 7. Figures 47(a) and (b) are schematic diagrams showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane according to Embodiment 7. Figure 48(a) is a diagram illustrating the position of the load distribution plate in the unloaded state according to Embodiment 7. Figure 48(b) is a diagram schematically showing the position of the load distribution plate in the loaded state according to Embodiment 7. Figure 49(a) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Comparative Examples 4 and 5. Figure 49(b) is a diagram showing the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 7.Figures 50(a) to (c) show the state of the load distribution plate and the first base member in relation to the simulations of Comparative Examples 4 and 5 and Embodiment 7. Figure 51 is a graph showing the relationship between load and capacitance in relation to the simulations of Comparative Examples 4 and 5 and Embodiment 7. Figure 52 is a schematic perspective view showing the configuration of multiple load distribution plates, multiple adhesive members, a structure, and a second base member in the manufacturing process according to Modified Example 14. Figure 53 is a schematic perspective view showing the configuration of the load distribution plate according to Modified Example 14. Figure 54 is a schematic plan view showing the configuration of the load sensor according to Modified Example 14. Figures 55(a) and (b) show schematic cross-sections of the element portion when the load sensor is cut with a plane parallel to the X-Z plane according to Modified Example 14. Figure 56 shows schematic cross-sections of the element portion when the load sensor is cut with a plane parallel to the X-Z plane according to Modified Example 18. Figures 57(a) and (b) are schematic plan views showing the configuration of the load sensor according to Modified Example 19. Figures 58(a) and (b) are schematic plan views showing the configuration of a load sensor according to modification example 19. Figure 59 is a schematic plan view showing the configuration of a load sensor according to modification example 20. Figures 60(a) and (b) are schematic diagrams showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to modification example 21. Figure 61 is a schematic diagram showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to modification example 22. Figure 62 is a schematic diagram showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to embodiment 8. Figure 63 is a schematic diagram showing the cross-section of the element portion when the load sensor is cut in a plane parallel to the X-Z plane, according to embodiment 9.

[0022] The present invention is applicable to input units for inputting information in accordance with applied load. Specifically, the present invention is applicable to input units for electronic devices such as PC keyboards, input units for game controllers, surface units for robot hands to detect objects, input units for inputting volume, airflow, light intensity, and temperature, input units for wearable devices such as smartwatches, input units for hearable devices such as wireless earphones, input units for touch panels, input units for adjusting ink volume in electronic pens, input units for adjusting light intensity and color in penlights, input units for adjusting light intensity in luminous clothing, and input units for adjusting volume in musical instruments.

[0023] The following embodiments are load sensors typically provided in the above-described apparatus. Such load sensors are referred to as "capacitive pressure-sensitive sensor elements," "capacitive pressure detection sensor elements," "pressure-sensitive switch elements," and so on. The following embodiments are one embodiment of the present invention, and the present invention is not limited in any way to the following embodiments.

[0024] Embodiments of the present invention will be described below with reference to the figures. For convenience, mutually orthogonal X, Y, and Z axes are indicated in each figure. The Z-axis direction is the height direction of the load sensor 1. For convenience, the positive Z-axis direction will be referred to as the upward direction.

[0025] <Embodiment 1> Figure 1(a) is a schematic perspective view showing the configuration of structure 1a in the manufacturing process.

[0026] The structure 1a comprises a first base member 10, a plurality of conductive elastic bodies 20, and a plurality of wirings 20a.

[0027] The first base member 10 is an elastic, flat plate-shaped member. The first base member 10 has a rectangular shape in plan view. The thickness of the first base member 10 is constant. When the thickness of the first base member 10 is small, it may also be called a sheet member or a film member. The upper surface 11 (the positive Z-axis side) and the lower surface 12 (the negative Z-axis side) of the first base member 10 are both parallel to the X-Y plane. The lower surface 12 is positioned downwards during assembly and is a facing surface that faces the second base member 70, which will be described later. The first base member 10 is insulating and is made of, for example, a non-conductive resin material or a non-conductive rubber material.

[0028] Multiple conductive elastic bodies 20 are installed in parallel on the lower surface 12 of the first base member 10. Here, three conductive elastic bodies 20 are arranged in the Y-axis direction. Each conductive elastic body 20 has a long, strip-like shape in the X-axis direction and is arranged in the Y-axis direction with a predetermined gap between them. The width, length, and thickness of the three conductive elastic bodies 20 are the same. The conductive elastic bodies 20 are conductive members with elasticity. One end of the wiring 20a is connected to the conductive elastic body 20, and the other end of the wiring 20a is connected to the detection circuit.

[0029] The conductive elastic body 20 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, carbon (C) is used as the conductive filler in the conductive elastic body 20. However, the filler used in the conductive elastic body 20 is not limited to these, and may be made of other conductive materials.

[0030] The conductive elastic body 20 is formed on the lower surface 12 of the first base member 10 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. These printing methods allow for the formation of the conductive elastic body 20 on the lower surface 12 of the first base member 10 with a thickness of approximately 0.001 mm to 0.5 mm. However, the method of forming the conductive elastic body 20 is not limited to printing methods.

[0031] Furthermore, an electrode pattern with a width in the Y-axis direction narrower than the conductive elastic body 20 may be arranged between the lower surface 12 of the first base member 10 and the conductive elastic body 20. This electrode pattern is also composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, Ag (silver) is used as the conductive filler in this electrode pattern. This electrode pattern is also formed on the lower surface 12 of the first base member 10 by the printing method described above.

[0032] Figure 1(b) is a schematic perspective view showing the configuration of structure 1b in the manufacturing process.

[0033] Structure 1b comprises structure 1a shown in Figure 1(a), a plurality of wires 30, and a plurality of threads 40.

[0034] Multiple wires 30 are arranged in parallel on the lower surface 12 of the first base member 10 so as to overlap with multiple conductive elastic bodies 20. Here, three sets of wire groups G1, each consisting of two wires 30 extending in the Y-axis direction, are arranged on the lower surface 12, for a total of six wires 30 arranged on the lower surface 12. The wire groups G1 are arranged at predetermined intervals in the X-axis direction. The two wires 30 of wire groups G1 are also arranged at predetermined intervals in the X-axis direction. The wires 30 are arranged between the first base member 10 and the second base member 70 in the state in which the load sensor 1 has been assembled, as will be described later.

[0035] As shown in Figure 5(a), the wire 30 is composed of a conductor wire 31 and a dielectric 32 that covers the surface of the conductor wire 31. In this embodiment, the cross-section of the wire 30 perpendicular to the direction in which the wire 30 extends has a circular shape with a diameter R1. The conductor wire 31 is a linear conductive member. The conductor wire 31 is made of a metallic material such as copper. The conductor wire 31 may be composed of a core wire made of glass and a conductive layer formed on its surface, or it may be composed of a core wire made of resin and a conductive layer formed on its surface, etc. The conductor wire 31 may also be a stranded wire made of wires made of a conductive metallic material twisted together. The dielectric 32 has electrical insulating properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc.

[0036] The negative Y-axis end of the conductor wire 31 is not covered by the dielectric 32, and this end is connected to the detection circuit. Two conductor wires 31 included in one wire group G1 are connected to each other in the detection circuit. Alternatively, two conductor wires 31 included in one wire group G1 may be connected to each other within the load sensor 1, and one of these conductor wires 31 may be connected to the detection circuit.

[0037] The multiple threads 40 have electrical insulating properties. Each thread 40 extends in the X-axis direction at the position of the gap between adjacent conductive elastic bodies 20, and sews multiple wires 30 to the first base member 10.

[0038] Figure 2 is a schematic perspective view showing the configuration of multiple load distribution plates 50, multiple adhesive members 60, structure 1b, and second base member 70 in the manufacturing process.

[0039] The load distribution plate 50 is a rigid, flat plate-shaped member. In plan view, the load distribution plate 50 has a rectangular shape, and its thickness is constant. In plan view, the load distribution plate 50 is positioned near the intersection of one wire group G1 and one conductive elastic body 20 (within the range of element section A, described later).

[0040] As described later, the load distribution plate 50 is positioned to evenly distribute the load applied to the upper surface 51 of the load distribution plate 50 to the corresponding element portion A. Therefore, it is preferable that the load distribution plate 50 has high rigidity. Specifically, the load distribution plate 50 has higher rigidity than the first base member 10. Furthermore, it is preferable that the load distribution plate 50 has rigidity that allows it to be treated as a rigid body in practical terms. For example, the thickness of the load distribution plate 50 is set to 0.1 mm or more, and the bending rigidity of the load distribution plate 50 is set to be greater than 10 MPa. The load distribution plate 50 is made of a highly rigid non-conductive resin material or a non-conductive metal. However, if the mass of the load distribution plate 50 is large, it will be as if a load has been applied to the element portion A in advance, so it is preferable that the mass of the load distribution plate 50 be small. Therefore, in this embodiment, the load distribution plate 50 is made of an acrylic resin.

[0041] The connecting member 60 adheres the lower surface 52 of the load dispersion plate 50 and the upper surface 11 of the first base member 10. The connecting member 60 is, for example, a double-sided tape or an adhesive. In the present embodiment, the connecting member 60 is disposed over the entire lower surface 52 of the load dispersion plate 50, and adheres the entire lower surface 52 of the load dispersion plate 50 to the upper surface 11 of the first base member 10.

[0042] The second base member 70 is a flat member. The second base member 70 has the same shape as the first base member 10 in a plan view. The thickness of the second base member 70 is constant. The upper surface 71 (the surface on the positive Z-axis side) and the lower surface 72 (the surface on the negative Z-axis side) of the second base member 70 are both parallel to the X-Y plane. The upper surface 71 is a facing surface facing the first base member 10. The second base member 70 has insulation properties and is made of, for example, a non-conductive resin material or a non-conductive rubber material.

[0043] As shown in FIG. 2, each load dispersion plate 50 is fixed via the connecting member 60 at a position corresponding to the element portion A described later. In the present embodiment, nine load dispersion plates 50 are arranged side by side in a matrix. Then, the lower surface 12 of the first base member 10 is overlapped so as to face the upper surface 71 of the second base member 70, and the vicinity of the outer periphery of the first base member 10 and the vicinity of the outer periphery of the second base member 70 are sewn with a thread (not shown). Thus, as shown in FIG. 3, the load sensor 1 is completed.

[0044] FIG. 3 is a perspective view schematically showing the configuration of the load sensor 1.

[0045] When using the load sensor 1, the load dispersion plate 50 is directed upward (positive Z-axis side), the second base member 70 is directed downward (negative Z-axis side), and the load sensor 1 is installed such that the negative Z-axis direction is the vertically downward direction, that is, the direction of gravity. In this case, the upper surface 51 of the load dispersion plate 50 (the upper surface of the load sensor 1) becomes the surface to which the load is applied, and the lower surface 72 of the second base member 70 (the lower surface of the load sensor 1) is installed on the installation surface. A floor board may be further disposed on the lower surface 72 of the second base member 70.

[0046] FIG. 4 is a plan view schematically showing the configuration of the load sensor 1.

[0047] In the load sensor 1, in a plan view, a plurality of element portions A arranged in a matrix are formed. In the load sensor 1 of FIG. 4, a total of nine element portions A arranged in the X-axis direction and the Y-axis direction are formed. One element portion A corresponds to a region including an intersection of the conductive elastic body 20 and a wire group G1 disposed below the conductive elastic body 20. In FIG. 4, for convenience, the range of the element portion A is indicated by a long dashed line.

[0048] One load distribution plate 50 is installed on the upper surface of the element portion A (the upper surface 11 of the first base member 10) so as to extend over the range of the corresponding element portion A in a plan view. A predetermined gap is provided between adjacent element portions A. The range of the outer peripheral shape formed by the nine element portions A in a plan view corresponds to the load detection surface of the load sensor 1.

[0049] When the lower surface of the load sensor 1 is installed on a predetermined installation surface and a load is applied to the upper surface of the load sensor 1, in the element portion A to which the load is applied, the capacitance between the conductive elastic body 20 and the conductor line 31 changes, and the load applied to the element portion A is detected based on the capacitance.

[0050] FIGS. 5(a) and 5(b) are diagrams schematically showing a cross section of the element portion A when the load sensor 1 is cut along a plane parallel to the X-Z plane.

[0051] FIG. 5(a) shows a state where no load is applied, and FIG. 5(b) shows a state where a load is applied. In FIGS. 5(a) and 5(b), the lower surface 72 on the negative Z-axis side of the second base member 70 is installed on the installation surface.

[0052] As shown in FIG. 5(a), one element portion A is composed of the first base member 10, the conductive elastic body 20, two wires 30, and the second base member 70 in the vicinity of the intersection of one conductive elastic body 20 and one wire group G1. In the present embodiment, one element portion A has two pressure-sensitive portions A1 whose capacitance changes due to a load.

[0053] The pressure-sensitive part A1 is composed of an element part A having at least a portion of the conductive elastic body 20, at least a portion of the conductor wire 31, and at least a portion of the dielectric 32, and the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 can change with load. Specifically, the width W1 of the pressure-sensitive part A1 in the X-axis direction is the length over which the conductive elastic body 20 can contact the wire 30, and if the diameter of the wire 30 is R1, the width W1 of the pressure-sensitive part A1 is πR1. The length of the pressure-sensitive part A1 in the Y-axis direction is the same as the length of the element part A in the Y-axis direction and coincides with the width of the conductive elastic body 20 in the Y-axis direction.

[0054] As shown in Figure 5(a), when no load is applied to element A, the conductive elastic body 20 and the wire 30 are in contact, and the conductive elastic body 20 is almost undeformed. From this state, as shown in Figure 5(b), when a load is applied downward to the upper surface 51 of the load distribution plate 50, the conductive elastic body 20 deforms due to the wire 30. At this time, the wire 30 is enveloped by the conductive elastic body 20, and the contact area between the wire 30 and the conductive elastic body 20 increases. As a result, the capacitance between the conductor wire 31 and the conductive elastic body 20 changes. The potential reflecting the change in capacitance based on the two pressure-sensitive parts A1 within element A is measured in the detection circuit, and the load applied to element A is calculated. In other words, element A detects the load applied to element A based on the capacitance of the pressure-sensitive parts A1.

[0055] By the way, in load detection by the load sensor 1, it is desirable to properly detect the load applied to element A even when a load is applied locally to element A. However, in a typical load sensor (comparative example) in which the load distribution plate 50 is not arranged, when a load is applied locally to element A, for example, at a relatively low load, the conductive elastic body 20 comes into contact with the second base member 70 near the load application point, and the load is supported. Alternatively, the conductive elastic body 20 bends and deforms, but the rate of increase in the contact area between the conductive elastic body 20 and the wire 30 becomes low, i.e., the sensitivity decreases. Thus, in the comparative example, it is possible that the load cannot be properly detected.

[0056] In contrast, in this embodiment, even if a localized load is applied to element A, the applied load is distributed by the load distribution plate 50 and evenly distributed across the two pressure-sensitive parts A1 extending in the Y-axis direction within element A. As a result, even when a load is applied locally to element A, the load applied to element A can be properly detected.

[0057] The effects of this embodiment will be explained below with reference to the simulation results.

[0058] Figure 6(a) shows the conditions for verifying the relationship between load and capacitance in the simulations of Comparative Examples 1 and 2. Figure 6(b) shows the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 1.

[0059] As shown in Figure 6(a), in the simulation configurations of Comparative Examples 1 and 2, four wires 30 are arranged at equal intervals between the first base member 10 and the second base member 70, and the load distribution plate 50 is not arranged. As shown in Figure 6(b), in the simulation configuration of Embodiment 1, compared to Comparative Examples 1 and 2 in Figure 6(a), the load distribution plate 50 is arranged on the upper surface of the first base member 10 in the range of element section A that spans the two central wires 30. The entire lower surface of the load distribution plate 50 is fixed to the upper surface of the first base member 10, as shown by the thick line. In this simulation, the change in the contact area between the conductive elastic body 20 and the wires 30 in response to a load is verified by the change in the contact area between the first base member 10 and the wires 30. Therefore, for convenience, the conductive elastic body 20 is omitted in this simulation.

[0060] As shown in Figures 6(a) and (b), the thickness T1 of the first base member 10 and the thickness T2 of the second base member 70 were both set to 0.5 mm. The width W2 in the X-axis direction of the first base member 10 and the second base member 70 was set to 24 mm. The diameter R1 of the wire 30 was set to 0.26 mm. In the load distribution plate 50, the thickness T3 was set to 0.4 mm and the width W3 in the X-axis direction was set to 10 mm. The configuration in Figures 6(a) and (b) was made to continue infinitely in the Y-axis direction, and the length of the element section A in the X-axis and Y-axis directions was set to 10 mm.

[0061] In the first base member 10, the material model was set to Neo-Hookean, with an initial shear modulus of 0.5 MPa and a compressibility factor of zero. In the wire 30 and the second base member 70, the modulus of elasticity was set to 200 GPa and Poisson's ratio to 0.3. In the load distribution plate 50, the modulus of elasticity was set to 3000 MPa and Poisson's ratio to 0.33, the same as for polyethylene terephthalate (PET).

[0062] In Comparative Example 1, a load was applied to the center of the upper surface of element A in the X-axis direction, while in Comparative Example 2, a load was applied near the edge of the upper surface of element A in the X-axis direction. For the load application areas in Comparative Examples 1 and 2, the width in the X-axis direction was set to 1 mm, and the width in the Y-axis direction was set to infinite. In Embodiment 1, a load was applied to the entire upper surface of the load distribution plate 50, and the load was evenly applied to the upper surface area of ​​the first base member 10 within the range of the load distribution plate 50. Here, since the load distribution plate 50 can be considered substantially rigid, a localized load applied to the center or near the edge of the load distribution plate 50 in the X-axis direction can be treated in simulation as if the load were evenly applied to the upper surface area of ​​the first base member 10 within the range of the load distribution plate 50. Therefore, in Embodiment 1, a load was applied to the entire upper surface of the load distribution plate 50.

[0063] However, in this simulation, instead of actually applying a load, in Comparative Examples 1 and 2, the first base member 10 was displaced in the negative Z-axis direction in the load application region, and in Embodiment 1, the load distribution plate 50 was displaced in the negative Z-axis direction.

[0064] In this simulation, for each step of the displacement corresponding to the load described above, the contact area between the two wires 30 corresponding to element A and the first base member 10 was calculated. The first base member 10 was then treated as a conductive elastic body 20, and the capacitance was approximated from the calculated contact area.

[0065] Figures 7(a) to 7(c) show the deformation of the first base member 10 in relation to this simulation.

[0066] Figures 7(a) to 7(c) show the strain state of the first base member 10 in the configurations of Comparative Examples 1 and 2 and Embodiment 1, respectively, represented by color. For convenience, the strain state in Figures 7(a) to 7(c) is represented in grayscale, with lighter colors indicating areas of greater strain. Figures 7(a) to 7(c) also show the load Ld used to apply the load (displacement).

[0067] As shown in Figure 7(a), in Comparative Example 1, the load Ld is positioned in the center of the element section A, and as shown in Figure 7(b), in Comparative Example 2, the load Ld is positioned near the edge of the element section A. Therefore, in both Comparative Examples 1 and 2, the first base member 10 near the position of the load Ld bends downward and comes into contact with the second base member 70. In these cases, since the load is supported by the second base member 70, the contact area between the first base member 10 and the wire 30 does not increase appropriately as the load increases.

[0068] On the other hand, as shown in Figure 7(c), in Embodiment 1, the load from the loaded material Ld is evenly applied to the first base member 10 in the area corresponding to the load distribution plate 50. As a result, the load is applied almost uniformly across the entire element section A, and the applied load is distributed across the two pressure-sensitive sections A1 (see Figure 5(b)) that extend in the Y-axis direction. Therefore, unlike Comparative Examples 1 and 2, the contact area between the first base member 10 and the wire 30 increases appropriately in response to the increase in load.

[0069] Figure 8 is a graph showing the relationship between load and capacitance in this simulation.

[0070] In Figure 8, the horizontal axis shows the displacement of the load distribution plate 50 converted into load, and the vertical axis shows the capacitance calculated from the contact area between the first base member 10 and the wire 30. In the graph of Figure 8, plots representing load and capacitance are connected by lines.

[0071] In Comparative Examples 1 and 2, the capacitance saturates at 1 pF to 2 pF even when the load increases. Therefore, in configurations without a load distribution plate 50, as in Comparative Examples 1 and 2, the load can only be detected in the low load range (approximately 0 N to 0.2 N in Figure 8), and the load cannot be properly detected in the high load range. Furthermore, in Comparative Examples 1 and 2, there is a discrepancy between the graphs, indicating that the detected load differs depending on the load application position. In Comparative Examples 1 and 2, the capacitance increased in the very low load range, and then saturated as the load increased. However, depending on the physical properties of each component, it is possible that the capacitance hardly increases even at low loads, or that the rate of increase is low, i.e., the sensitivity is low.

[0072] On the other hand, in Embodiment 1, the capacitance increases without saturating in response to the load. This shows that, in a configuration with a load distribution plate 50 as in Embodiment 1, in addition to being able to properly detect the load due to the load distribution by the load distribution plate 50, the load can be properly detected over a wide range of loads.

[0073] <Effects of Embodiment 1> According to Embodiment 1, the following effects are achieved.

[0074] As shown in Figure 5(a), the load sensor 1 has a plurality of pressure-sensitive parts A1 whose capacitance changes with load, and includes an element part A that detects load based on the capacitance of the plurality of pressure-sensitive parts A1, and a load distribution plate 50 that is placed on top of the element part A and distributes the applied load.

[0075] In this configuration, the load applied to element A is distributed by the load distribution plate 50 and applied to the pressure-sensitive part A1. As a result, even when a load is applied locally to element A, the load applied to element A can be properly detected.

[0076] As shown in Figure 5(a), the element section A has a plurality of pressure-sensitive sections A1, and the load distribution plate 50 is superimposed on the element section A in a range that spans the plurality of pressure-sensitive sections A1.

[0077] With this configuration, the load applied to element A is distributed evenly across multiple pressure-sensitive parts A1. This allows for increased sensitivity of element A while also enabling proper detection of the load applied to element A.

[0078] As shown in Figure 5(a), the element A comprises a sheet-like first base member 10 (base member) having elasticity and an upper surface 11 and a lower surface 12 located opposite the upper surface 11, a conductive elastic body 20 formed on the lower surface 12 of the first base member 10 (base member), a plurality of conductor wires 31 arranged opposite to the conductive elastic body 20, and a dielectric 32 interposed between the conductive elastic body 20 and each of the plurality of conductor wires 31. The pressure-sensitive part A1 is composed of a portion of the element A having at least a part of the conductive elastic body 20, at least a part of the conductor wires 31, and at least a part of the dielectric 32, and the contact area between the conductive elastic body 20 and the conductor wires 31 via the dielectric 32 can change with load. The load distribution plate 50 is superimposed on the upper surface 11 of the first base member 10 (base member).

[0079] This configuration allows for a simpler design of the pressure-sensitive section A1.

[0080] As shown in Figure 5(a), the dielectric 32 is installed so as to cover the surface of the conductor wire 31.

[0081] With this configuration, the dielectric 32 can be placed between the conductive elastic body 20 and the conductor wire 31 simply by covering the surface of the conductor wire 31 with the dielectric 32.

[0082] As shown in Figure 4, in a plan view in the Z-axis direction (the direction in which the element A is located relative to the load distribution plate 50), multiple element A units are arranged in a line.

[0083] With this configuration, the load detection surface of the load sensor 1 can be widened, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element A.

[0084] As shown in Figure 4, multiple element units A are arranged in a matrix.

[0085] With this configuration, a two-dimensional (matrix-like) load distribution can be detected on the load detection surface of the load sensor 1.

[0086] As shown in Figure 2, the load sensor 1 further includes an adhesive member 60 for fixing the load distribution plate 50 and the element part A.

[0087] With this configuration, the load distribution plate 50 can be fixed to the element section A with a simple structure.

[0088] <Example of modification 1> In Embodiment 1, one load distribution plate 50 was arranged in one element section A so as to extend to the area corresponding to the element section A, but two or more load distribution plates 50 may be arranged.

[0089] Figure 9 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0090] In this modified example, compared to Embodiment 1 shown in Figure 4, two load distribution plates 50 are arranged for one element section A. The two load distribution plates 50 arranged for one element section A are aligned in the Y-axis direction with a gap between them and have the same shape. The length of the load distribution plate 50 in the X-axis direction in this modified example is the same as the length of the load distribution plate 50 in the X-axis direction in Embodiment 1, and the length of the load distribution plate 50 in the Y-axis direction in this modified example is shorter than the length of the load distribution plate 50 in the Y-axis direction in Embodiment 1. In one element section A, both the load distribution plate 50 on the positive Y-axis side and the load distribution plate 50 on the negative Y-axis side are arranged to straddle the two pressure-sensitive sections A1 (see Figure 5(a)) within the element section A.

[0091] In this modified example as well, the adhesive member 60 (see Figure 2) is positioned over the entire lower surface 52 of each load distribution plate 50, and the entire lower surface 52 of each load distribution plate 50 is bonded to the upper surface 11 of the first base member 10.

[0092] <Effects of Modification Example 1> As shown in Figure 9, similar to Embodiment 1, the load distribution plate 50 is superimposed on the element part A in a range that spans multiple pressure-sensitive parts A1. In this configuration as well, when a load is applied locally to the element part A, the load applied to the element part A is distributed more evenly to the multiple pressure-sensitive parts A1 compared to a configuration in which the load distribution plate 50 is not arranged (comparative example). As a result, the load applied to the element part A can be detected appropriately.

[0093] Furthermore, compared to the case where only one load distribution plate 50 is arranged as in Embodiment 1, the area of ​​each load distribution plate 50 is smaller, so the required rigidity of the load distribution plate 50 can be set lower.

[0094] However, the load applied to either the positive or negative Y-axis load distribution plate 50 of element section A will be applied only to the corresponding load distribution plate 50. In this case, the load per unit area received by the load distribution plate 50 increases, thus reducing the maximum detectable load. Therefore, if you want to measure up to high loads, it is preferable to arrange one load distribution plate 50 within the range of element section A, as in Embodiment 1.

[0095] <Example of modification 2> In Example of modification 1, the two load distribution plates 50 placed in one element section A were arranged side by side in the Y-axis direction, but they may also be arranged side by side in the X-axis direction.

[0096] Figure 10 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0097] In this modified example, compared to Modified Example 1 shown in Figure 9, the two load distribution plates 50 arranged in one element section A are aligned in the X-axis direction with a gap between them and have the same shape. The length of the load distribution plate 50 in the Y-axis direction in this modified example is the same as the length of the load distribution plate 50 in the Y-axis direction in Embodiment 1, and the length of the load distribution plate 50 in the X-axis direction in this modified example is shorter than the length of the load distribution plate 50 in the X-axis direction in Embodiment 1. In one element section A, the load distribution plates 50 on the positive X-axis side and the negative X-axis side are arranged to overlap the pressure-sensitive sections A1 (see Figure 5(a)) on the positive X-axis side and the negative X-axis side within the element section A, respectively. More specifically, each load distribution plate 50 is arranged so that its centerline in the X-axis direction overlaps the wire 30.

[0098] In this modified example as well, the adhesive member 60 (see Figure 2) is positioned over the entire lower surface 52 of each load distribution plate 50, and the entire lower surface 52 of each load distribution plate 50 is bonded to the upper surface 11 of the first base member 10.

[0099] <Effects of Modification Example 2> As shown in Figure 10, the load distribution plate 50 is arranged to correspond to the entire pressure-sensitive section A1 extending in the Y-axis direction. In this configuration as well, when a load is applied locally to the element section A, the load applied to the element section A is distributed more evenly to the single pressure-sensitive section A1 compared to the configuration in which the load distribution plate 50 is not arranged (comparative example). As a result, the load applied to the element section A can be detected appropriately.

[0100] Furthermore, because the area of ​​each load distribution plate 50 is reduced, the required rigidity of the load distribution plate 50 can be set lower compared to the case where only one load distribution plate 50 is provided.

[0101] However, the load applied to either the positive X-axis side or the negative X-axis side load distribution plate 50 of element section A will be applied only to the corresponding load distribution plate 50. In this case, the load per unit area received by the load distribution plate 50 increases, thus reducing the maximum detectable load. Therefore, if you want to measure up to high loads, it is preferable to arrange one load distribution plate 50 within the range of element section A, as in Embodiment 1.

[0102] Furthermore, in this modified example, the locally applied load makes the load distribution plate 50 more likely to rotate around one of the wires 30 as an axis. Therefore, in order to suppress the rotation of the load distribution plate 50, it is preferable that the load distribution plate 50 is arranged to straddle the two pressure-sensitive parts A1, as in Embodiment 1 and Modified Example 1.

[0103] <Example of modification 3> In Embodiment 1, as shown in Figure 2, the adhesive member 60 was arranged on the entire lower surface 52 of the load distribution plate 50. However, areas where the adhesive member 60 is not arranged may be provided between adjacent wires 30 (areas that do not overlap with the wires 30 in a plan view).

[0104] Figure 11 is a schematic perspective view showing the configuration of the multiple load distribution plates 50, multiple adhesive members 60, structure 1b, and second base member 70 in the manufacturing process according to this modified example.

[0105] In this modified example, compared to Embodiment 1 shown in Figure 2, two adhesive members 60 are arranged for one load distribution plate 50. The length of the adhesive member 60 in the Y-axis direction in this modified example is the same as the length of the adhesive member 60 in the Y-axis direction in Embodiment 1, and the length of the adhesive member 60 in the X-axis direction in this modified example is shorter than the length of the adhesive member 60 in the X-axis direction in Embodiment 1.

[0106] Figure 12 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0107] In Figure 12, for convenience, the area of ​​the adhesive members 60 is illustrated by halftone dots enclosed by a dashed line. Each adhesive member 60 is positioned such that its centerline in the X-axis direction coincides with the wire 30. The positioning range of one adhesive member 60 is limited to the vicinity of one pressure-sensitive part A1 (see Figure 13(a)). In a plan view, the area in which one adhesive member 60 is positioned is included within the range of one pressure-sensitive part A1. For example, the area in which one adhesive member 60 is positioned is equal to the range of one pressure-sensitive part A1, and the width of the adhesive member 60 in the X-axis direction is the same as the width W1 of the pressure-sensitive part A1 in the X-axis direction.

[0108] Specifically, in a plan view, the adhesive member 60 is positioned within the range of the upper surface 11 of the first base member 10 that corresponds to the range in which the conductive elastic body 20 can contact the conductor wire 31 via the dielectric 32. In particular, in the configuration of this modified example, in a plan view, the range in which the adhesive member 60 is positioned in the direction perpendicular to the extension direction (Y direction) of the conductor wire 31 (width W1 in Figure 12) is greater than zero, includes at least a part of the range in which the dielectric 32 and the conductive elastic body 20 are in contact when no load is applied, and is the circumference (= πR1) with the outer diameter of the dielectric 32 covering the conductor wire 31 as its diameter, but may be within a range of half the length of the circumference (= πR1 / 2) (see Figure 14 and width W4 described later). The width of the adhesive member 60 may be less than half of the above circumference. The width of the adhesive member 60 may be less than half of the above circumference.

[0109] Figures 13(a) and 13(b) schematically show the cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to this modified example.

[0110] As shown in Figure 13(a), when no load is applied to element A, the conductive elastic body 20 and the wire 30 are in contact, similar to Embodiment 1, and the conductive elastic body 20 is almost undeformed. From this state, as shown in Figure 13(b), when a load is applied downward to the upper surface 51 of the load distribution plate 50, the wire 30 is enveloped by the conductive elastic body 20, similar to Embodiment 1, and the contact area between the wire 30 and the conductive elastic body 20 increases.

[0111] In this modified example, since the first base member 10 and the load distribution plate 50 are not fixed between two adjacent adhesive members 60 in the X-axis direction, the first base member 10 in this region bends downward away from the load distribution plate 50. As a result, compared to Embodiment 1 shown in Figure 5(b), the wire 30 is further encased in the conductive elastic body 20, and the contact area between the wire 30 and the conductive elastic body 20 is further increased. Therefore, according to this modified example, the capacitance between the conductor wire 31 and the conductive elastic body 20 increases further in response to the increase in load, thereby improving the sensitivity of element A. From this viewpoint, it is preferable that the adhesive member 60 is not particularly positioned near the midpoint between two adjacent wires 30.

[0112] Next, we will explain the effects of this modification example by referring to the simulation results.

[0113] Figure 14(a) shows the conditions for verifying the relationship between load and capacitance in the simulation of this modified example.

[0114] In this modified example, the simulation conditions are different from those shown in Figure 6(b), in that the width W4 of the adhesive member 60 in the X-axis direction is limited to correspond to the pressure-sensitive part A1. In this simulation, the width W4 of the adhesive member 60 in the X-axis direction was set to 0.4 mm, which is shorter than half the length of the width of the pressure-sensitive part A1 in the X-axis direction (= πR1 / 2). In this modified example as well, the load was applied to the entire upper surface of the load distribution plate 50, and the load was evenly applied to the upper surface area of ​​the first base member 10 within the range of the load distribution plate 50. The width W4 may be less than or equal to half the length of the width of the pressure-sensitive part A1 (= πR1 / 2), or it may be less than that.

[0115] Figure 14(b) shows the deformation of the first base member 10 in relation to this simulation.

[0116] In this modified example as well, the load from the loaded material Ld is evenly applied to the two pressure-sensitive parts A1 within the element A (see Figure 13(a)). As a result, the load is applied almost equally to the two pressure-sensitive parts A1, and, as in Embodiment 1, the contact area between the first base member 10 and the wire 30 increases appropriately in response to the increase in load.

[0117] Figure 15 is a graph showing the relationship between load and capacitance in this simulation.

[0118] In the graph of Figure 15, the plots representing load and capacitance are connected by lines. Furthermore, the graph of Embodiment 1 shown in Figure 8 is shown alongside the graph of Modification Example 3 in Figure 15.

[0119] In this modified example as well, the capacitance increases without saturating in response to the load. This means that, similar to Embodiment 1, the load can be properly detected by distributing the load by the load distribution plate 50, and in addition, the load can be properly detected over a wide range of loads. Furthermore, in this modified example, the capacitance is about 5% to 10% larger than in Embodiment 1, so it can be shown that the sensitivity can be increased compared to Embodiment 1.

[0120] In this simulation, in the configuration of Modified Example 3, the width W4 of the adhesive member 60 was set to less than half the width of the pressure-sensitive part A1, but it may also be set to be longer than half the width of the pressure-sensitive part A1 and less than or equal to the width of the pressure-sensitive part A1. In this case, the graph showing the relationship between load and capacitance is considered to be located between the graph of Modified Example 3 and the graph of Embodiment 1 in Figure 15. Therefore, even when the adhesive member 60 is placed within the range of the upper surface 11 of the first base member 10 corresponding to the range of the pressure-sensitive part A1 (the range in which the conductive elastic body 20 can contact the conductor wire 31 via the dielectric 32) in a plan view, the sensitivity can be increased compared to Embodiment 1.

[0121] <Effects of Modification Example 3> As shown in Figures 13(a) and (b), the placement range of the adhesive member 60 is limited to the vicinity of the pressure-sensitive part A1.

[0122] In this configuration, the load distribution plate 50 and the first base member 10 are not fixed by the adhesive member 60 in areas other than near the pressure-sensitive part A1. As a result, when a load is applied, the first base member 10 separates from the load distribution plate 50 in areas other than near the pressure-sensitive part A1, and the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 can more easily cover the area around the wire 30 (conductor wire 31). As a result, the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 is more likely to increase, thereby increasing the sensitivity of the load sensor 1. In addition, since the adhesive member 60 is positioned near the pressure-sensitive part A1, the load applied to the pressure-sensitive part A1 can be reliably transmitted to the element part A.

[0123] As shown in Figures 13(a) and 13(b), in a plan view in the Z-axis direction (the direction in which the element A is located relative to the load distribution plate 50), the adhesive member 60 is not positioned between adjacent pressure-sensitive parts A1.

[0124] With this configuration, when a load is applied, the first base member 10 reliably separates from the load distribution plate 50 between adjacent pressure-sensitive parts A1, making it easier for the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 to cover the wire 30 (conductor wire 31). This increases the sensitivity of the element A.

[0125] As shown in Figures 13(a) and 14(a), in a plan view in the Z-axis direction (the direction in which the element A is located relative to the load distribution plate 50), the adhesive member 60 is positioned within the range of the pressure-sensitive portion A1.

[0126] With this configuration, when a load is applied, the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 can more easily cover the area around the wire 30 (conductor wire 31), thereby increasing sensitivity.

[0127] <Example of modification 4> In Example of modification 3, as shown in Figure 12, the arrangement range of the adhesive members 60 in the Y-axis direction coincided with the range of the pressure-sensitive section A1. However, the arrangement range of the adhesive members 60 in the Y-axis direction may be smaller than the range of the pressure-sensitive section A1. For example, one adhesive member 60 may be provided in an island-like manner within the range of the corresponding pressure-sensitive section A1.

[0128] Figure 16 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0129] In this modified example, the size and number of adhesive members 60 have been changed compared to modified example 3 shown in Figure 12. The length of the adhesive members 60 in the X-axis direction in this modified example is the same as the length of the adhesive members 60 in the X-axis direction in modified example 3, but the length of the adhesive members 60 in the Y-axis direction in this modified example is shorter than the length of the adhesive members 60 in the Y-axis direction in modified example 3. In addition, in this modified example, two adhesive members 60 are arranged with a gap between them for one pressure-sensitive part A1 within the element part A.

[0130] <Effects of Modification Example 4> In this modification example as well, when a load is applied, the first base member 10 separates from the load distribution plate 50 between adjacent pressure-sensitive parts A1, making it easier for the conductive elastic body 20 to cover the wire 30. This increases the sensitivity of the element A. In addition, in this modification example, non-adhesive areas are provided on the positive and negative Y-axis sides of the adhesive member 60 in the pressure-sensitive part A1, where the load distribution plate 50 and the first base member 10 are not bonded. As a result, the first base member 10 separates from the load distribution plate 50 in the non-adhesive areas, further increasing the sensitivity of the element A compared to modification example 3.

[0131] Furthermore, the area in the pressure-sensitive section A1 where the adhesive member 60 is placed may be even narrower in the X-axis and Y-axis directions. However, if the area where the adhesive member 60 is placed becomes narrower, the adhesive force between the load distribution plate 50 and the first base member 10 will weaken. Therefore, if adhesive force is important, it is preferable to place the adhesive member 60 over the entire area of ​​the pressure-sensitive section A1, as shown in the modified example 3 in Figure 12. Also, if the adhesive force is to be further increased, it is preferable to place the adhesive member 60 over the area of ​​the lower surface 52 of the load distribution plate 50, as shown in Embodiment 1.

[0132] <Example of modification 5> In Example of modification 3, the lower surface 52 of the load distribution plate 50 was parallel to the X-Y plane, but it is not limited to this, and only the area where the adhesive member 60 is placed may be parallel to the X-Y plane.

[0133] Figure 17(a) is a schematic perspective view showing the configuration of the load distribution plate 50 according to this modified example.

[0134] The lower surface 52 of the load distribution plate 50 in this modified example is composed of two planes 52a parallel to the X-Y plane, four inclined surfaces 52b adjacent to planes 52a, and one plane 52c located on the positive Z-axis side of plane 52a and parallel to the X-Y plane. Planes 52a and 52c extend in the Y-axis direction. Plane 52a and the pair of inclined surfaces 52b flanking plane 52a form a ridge shape extending in the Y-axis direction on the lower surface 52.

[0135] Figure 17(b) schematically shows a cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to this modified example.

[0136] In this modified example, the adhesive member 60 is placed only in the area of ​​the flat surface 52a of the load distribution plate 50. The load distribution plate 50 and the first base member 10 are in close contact via the adhesive member 60 on the flat surface 52a, and are separated in the Z-axis direction in areas other than the flat surface 52a (inclined surface 52b and flat surface 52c).

[0137] <Effects of Modification Example 5> In this modification example as well, when a load is applied, the first base member 10 is separated from the load distribution plate 50 in areas other than the pressure-sensitive part A1, making it easier for the conductive elastic body 20 to cover the area around the wire 30. This makes it possible to increase the sensitivity of the element part A. In addition, in this modification example, the load applied to the load distribution plate 50 is reliably concentrated only on the pressure-sensitive part A1, making it possible to further increase the sensitivity compared to modification example 3.

[0138] <Modification Example 6> In Embodiment 1, the dielectric 32 was arranged to cover the surface of the conductor wire 31, but the dielectric 32 is not limited to this, and may be arranged between the conductive elastic body 20 and the conductor wire 31. For example, as shown in Figure 18(a), it may be arranged on the lower surface (the negative Z-axis side) of the conductive elastic body 20.

[0139] In this modified example, the dielectric 32 is formed on the lower surface of the conductive elastic body 20, compared to Embodiment 1 shown in Figure 5(a). Alternatively, the dielectric 32 may be formed on the lower surface 12 of the first base member 10 so as to span across the lower surfaces of all conductive elastic bodies 20.

[0140] Furthermore, as shown in Figure 18(a), the adhesive member 60 may be arranged in the area of ​​the lower surface 52 of the load distribution plate 50, similar to Embodiment 1, or as shown in Figure 18(b), it may be arranged within the area of ​​the pressure-sensitive part A1, similar to Modified Example 3. Also, similar to Modified Example 5 in Figure 17(b), a flat surface 52a corresponding to the pressure-sensitive part A1 may be provided on the lower surface 52 of the load distribution plate 50.

[0141] <Modification Example 7> In Embodiment 1, one element A had two pressure-sensitive parts A1, but as shown in Figure 19, one element A may have one pressure-sensitive part A1. In this case, one conductive elastic body 20 and one conductor wire 31 intersect in one element A. In this modification example as well, when a local load is applied to the element A, the applied load is distributed by the load distribution plate 50, so that the load applied to the element A can be properly detected.

[0142] <Embodiment 2> In Embodiment 1, the pressure-sensitive portion A1 was formed by the overlapping of the conductive elastic body 20 and the conductor wire 31 via the dielectric 32, but the pressure-sensitive portion A1 may be formed by other configurations. In Embodiment 2, the pressure-sensitive portion A1 is formed by the overlapping of the electrode and the conductive elastic body with a protrusion shape via the dielectric.

[0143] Figure 20 is a schematic diagram showing a cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to Embodiment 2. The following describes a configuration that differs from Embodiment 1.

[0144] In Embodiment 2, the load sensor 1 is provided with one element A. A conductive elastic body 110 is formed on the lower surface 12 of the first base member 10. The conductive elastic body 110 is made of the same material as the conductive elastic body 20 in Embodiment 1. On the lower surface of the conductive elastic body 110, a plurality of protrusions 111 are integrally formed within the area of ​​the load distribution plate 50 in a plan view. The protrusions 111 have a frustoconical shape in which the diameter in the X-Y plane decreases as they extend downward. An electrode 120 is formed on the upper surface 71 of the second base member 70. The electrode 120 is made of a conductive metal (for example, aluminum). A dielectric 130 is formed on the upper surface of the electrode 120. The dielectric 130 is made of the same material as the dielectric 32 in Embodiment 1.

[0145] When a load is applied, the protrusions 111 of the conductive elastic body 110 contract in accordance with the load, increasing the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130. This changes the capacitance between the conductive elastic body 110 and the electrode 120. The potential reflecting this change in capacitance is then measured in the detection circuit, and the load applied to element A is calculated.

[0146] The pressure-sensitive portion A1 is composed of a part of element A in which the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130 can change with load. In a plan view, the pressure-sensitive portion A1 is a region with a width W5 centered on the projection 111.

[0147] In Embodiment 2, as in Embodiment 1, the load sensor 1 includes an element unit A that has a plurality of pressure-sensitive parts A1 whose capacitance changes with load, and detects the load based on the capacitance of the plurality of pressure-sensitive parts A1, and a load distribution plate 50 that is placed on top of the element unit A and distributes the applied load. With this configuration, the load applied to the element unit A is distributed by the load distribution plate 50 and applied to the pressure-sensitive parts A1. As a result, even when a load is applied locally to the element unit A, the load applied to the element unit A can be properly detected.

[0148] <Embodiment 3> In Embodiment 1, the contact area between the two electrodes (conductive elastic body 20 and conductor wire 31) via the dielectric 32 increased due to the deformation of the first base member 10 and the conductive elastic body 20 by the application of a load. However, the invention is not limited to this, and the contact area between the two electrodes via the dielectric may also increase due to deformation of other parts.

[0149] Figure 21 is a schematic diagram showing a cross-section of the element portion A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to Embodiment 3. The following describes a configuration that differs from Embodiment 1.

[0150] In Embodiment 3, a second base member 210 is provided in place of the second base member 70. The second base member 210 is made of the same material as the first base member 10. A plurality of conductive elastic bodies 220 are formed on the upper surface 211 of the second base member 210 with gaps in the X-axis direction. The lower surface 212 of the second base member 210 is placed on the installation surface. A plurality of conductive elastic bodies 230 are formed on the lower surface 12 of the first base member 10 with gaps in the Y-axis direction. The conductive elastic bodies 220 and 230 are made of the same material as, for example, the conductive elastic body 20 of Embodiment 1. A layered dielectric 240 is provided between the conductive elastic bodies 220 and 230. The dielectric 240 is made of, for example, a resin material having electrical insulation and elasticity.

[0151] When a load is applied, the first base member 10, the second base member 210, the conductive elastic bodies 220 and 230, and the dielectric 240 deform, increasing the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240. This changes the capacitance between the conductive elastic body 220 and the conductive elastic body 230. The potential reflecting this change in capacitance is measured in the detection circuit, and the load applied to element A is calculated.

[0152] The pressure-sensitive section A1 is composed of a portion of element A in which the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240 can change with load. The width of the pressure-sensitive section A1 in the X-axis direction is W6.

[0153] In Embodiment 3, as in Embodiment 1, the load sensor 1 includes an element unit A that has a plurality of pressure-sensitive parts A1 whose capacitance changes with load, and detects the load based on the capacitance of the plurality of pressure-sensitive parts A1, and a load distribution plate 50 that is placed on top of the element unit A and distributes the applied load. With this configuration, the load applied to the element unit A is distributed by the load distribution plate 50 and applied to the pressure-sensitive parts A1. As a result, even when a load is applied locally to the element unit A, the load applied to the element unit A can be properly detected.

[0154] <Other Modification Examples> In embodiments 1 to 3 and modifications 1 to 7 described above, a single-layer load distribution plate 50 was placed in element section A, but two or more load distribution plates 50 may be stacked and arranged.

[0155] In Embodiment 1 and Modifications 1 to 7, one or two load distribution plates 50 were arranged in a single element section A so as to extend over the area corresponding to that element section A, but three or more load distribution plates 50 may be arranged.

[0156] In Embodiment 1 and Modification Examples 1 to 7 described above, three element units A were arranged in the X-axis direction and the Y-axis direction, respectively. However, the number of element units A arranged in the X-axis direction and the Y-axis direction may be one, two, or four or more.

[0157] In Embodiment 1 and Modifications 1 to 7 described above, one wire group G1 included one or two wires 30, but it is not limited to this, and one wire group G1 may include three or more wires 30. That is, one element A may have three or more pressure-sensitive parts A1.

[0158] In embodiments 2 and 3 described above, one element A had three pressure-sensitive parts A1, but it may have one, two, or four or more pressure-sensitive parts A1.

[0159] In Embodiment 1 and Modifications 1 to 7 described above, the conductive elastic body 20 was placed only on the lower surface 12 of the first base member 10, but it may also be placed on both the lower surface 12 of the first base member 10 and the upper surface 71 of the second base member 70. In this case, in Modification 6, the dielectric 32 is also placed on the upper surface of the conductive elastic body 20 placed on the upper surface 71 of the second base member 70.

[0160] In Embodiment 1 and Modification Examples 1 to 7 described above, the cross-sectional shape of the conductor wire 31 was circular, but it is not limited to this, and other shapes such as ellipse or pseudo-circular may also be used.

[0161] In Embodiment 1 and Modifications 1 to 7 described above, the direction in which the conductive elastic body 20 extends and the direction in which the wire 30 extends are perpendicular to each other. However, the invention is not limited to this, and the angle between these directions may be an angle other than 90°. That is, the wire 30 may intersect the conductive elastic body 20 at an oblique angle.

[0162] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0163] (Note) The above description of embodiments discloses the following technologies.

[0164] (Technical 1) A load sensor comprising: one or more element units, each of the one or more element units having one or more pressure-sensitive units whose capacitance changes with load, and detecting load based on the capacitance of the one or more pressure-sensitive units; and one or more load-distributing plates, each of which a corresponding load-distributing plate is superimposed on each element unit, distributing the applied load.

[0165] According to this technology, the load applied to the element is distributed by the load distribution plate and then applied to the pressure-sensitive part. As a result, even when a load is applied locally to the element, the load applied to the element can be properly detected.

[0166] (Technology 2) A load sensor according to Technology 1, wherein one or more pressure-sensitive parts include a plurality of pressure-sensitive parts, and a corresponding load distribution plate is superimposed on each of the element parts in a range that spans the plurality of pressure-sensitive parts.

[0167] This technology ensures that the load applied to the element is evenly distributed across multiple pressure-sensitive areas. This allows for improved sensitivity of the element while accurately detecting the load applied to it.

[0168] (Technology 3) A load sensor according to Technology 1 or 2, wherein each element portion comprises: a sheet-like base member having elasticity and having an upper surface and a lower surface located opposite to the upper surface; a conductive elastic body formed on the lower surface of the base member; one or more conductor wires arranged opposite to the conductive elastic body; and a dielectric interposed between the conductive elastic body and each of the one or more conductor wires; each of the one or more pressure-sensitive portions comprises at least a part of the conductive elastic body, at least a part of one corresponding conductor among the plurality of conductor wires, and at least a part of the dielectric, and each portion of the element portion is configured such that the contact area between the conductive elastic body and the at least part of one corresponding conductor wire via the dielectric can change with load; and a corresponding load distribution plate is superimposed on the upper surface of the base member.

[0169] This technology allows for a simpler configuration of the pressure-sensitive element.

[0170] (Technology 4) A load sensor according to Technology 3, characterized in that the dielectric is installed so as to cover the surface of one or more of the conductor wires.

[0171] According to this technology, a dielectric material can be placed between a conductive elastic material and a conductor wire simply by coating the surface of the conductor wire with a dielectric material.

[0172] (Technology 5) A load sensor according to any one of Technology 1 to 4, characterized in that one or more element parts include multiple element parts, and in a plan view from a corresponding load distribution plate in the direction in which each element part is located, the multiple element parts are arranged side by side.

[0173] This technology allows for an expanded load detection surface of the load sensor, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element.

[0174] (Technical 6) A load sensor as described in Technical 5, characterized in that a plurality of the element portions are arranged in a matrix.

[0175] This technology allows for the detection of a two-dimensional (matrix-like) load distribution on the load detection surface of a load sensor.

[0176] (Technical 7) A load sensor according to any one of Technical 1 to 6, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions.

[0177] This technology allows the load distribution plate to be fixed to the element with a simple configuration.

[0178] (Technical 8) A load sensor according to Technical 7, characterized in that, in a plan view from a corresponding load distribution plate in the direction in which each element portion is located, the adhesive member is not positioned between adjacent pressure-sensitive portions of at least one or more pressure-sensitive portions.

[0179] According to this technology, when a load is applied, the base member reliably separates from the load distribution plate between adjacent pressure-sensitive parts, making it easier for the conductive elastic material formed on the underside of the base member to cover the conductor wire. This increases the sensitivity of the element.

[0180] (Technical 9) A load sensor according to Technical 7 or 8, characterized in that, in a plan view from a corresponding load distribution plate in the direction in which each element portion is located, the adhesive member is positioned within the range of one or more pressure-sensitive portions.

[0181] According to this technology, when a load is applied, the conductive elastic material formed on the underside of the base member can more easily cover the conductor wire, thereby increasing sensitivity.

[0182] (Technical 10) A load sensor according to Technical 3 or 4, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions, wherein the contact area changes as the base member and the conductive elastic body deform at each of the pressure-sensitive portions, and in a plan view from the corresponding load distribution plate in the direction in which each of the element portions is located, the adhesive member is positioned within the range of the upper surface of the base member corresponding to the range in which the conductive elastic body can contact the corresponding conductor wire via the dielectric.

[0183] (Technical 11) A load sensor according to Technical 3 or 4, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions, wherein the contact area changes as the base member and the conductive elastic body deform at each of the pressure-sensitive portions, and in a plan view from the corresponding load distribution plate in the direction in which each of the element portions is located, the range in which the adhesive member is positioned in the direction perpendicular to the extending direction of the corresponding conductor wire includes at least a portion of the range in which the dielectric and the conductive elastic body are in contact when no load is applied, and is within a range of half the length of the circumference whose diameter is the outer diameter of the dielectric covering the corresponding conductor wire.

[0184] <Embodiment 4> Figure 22(a) is a schematic perspective view showing the configuration of structure 1a in the manufacturing process.

[0185] The structure 1a comprises a first base member 10, a plurality of conductive elastic bodies 20, and a plurality of wirings 20a.

[0186] The first base member 10 is an elastic, sheet-like member. The first base member 10 has a rectangular shape in plan view. The thickness of the first base member 10 is constant. The upper surface 11 (the positive Z-axis side) and the lower surface 12 (the negative Z-axis side) of the first base member 10 are both parallel to the X-Y plane. The lower surface 12 is positioned downwards during assembly and is the opposing surface that faces the second base member 70, which will be described later. The first base member 10 is insulating and is made of, for example, a non-conductive resin material or a non-conductive rubber material.

[0187] Multiple conductive elastic bodies 20 are installed in parallel on the lower surface 12 of the first base member 10. Here, three conductive elastic bodies 20 are arranged in the Y-axis direction. Each conductive elastic body 20 has a long, strip-like shape in the X-axis direction and is arranged in the Y-axis direction with a predetermined gap between them. The width, length, and thickness of the three conductive elastic bodies 20 are the same. The conductive elastic bodies 20 are conductive members with elasticity. One end of the wiring 20a is connected to the conductive elastic body 20, and the other end of the wiring 20a is connected to the detection circuit.

[0188] The conductive elastic body 20 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, carbon (C) is used as the conductive filler in the conductive elastic body 20. However, the filler used in the conductive elastic body 20 is not limited to these, and may be made of other conductive materials.

[0189] The conductive elastic body 20 is formed on the lower surface 12 of the first base member 10 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. These printing methods allow for the formation of the conductive elastic body 20 on the lower surface 12 of the first base member 10 with a thickness of approximately 0.001 mm to 0.5 mm. However, the method of forming the conductive elastic body 20 is not limited to printing methods.

[0190] Furthermore, an electrode pattern with a width in the Y-axis direction narrower than the conductive elastic body 20 may be arranged between the lower surface 12 of the first base member 10 and the conductive elastic body 20. This electrode pattern is also composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, Ag (silver) is used as the conductive filler in this electrode pattern. This electrode pattern is also formed on the lower surface 12 of the first base member 10 by the printing method described above.

[0191] Figure 22(b) is a schematic perspective view showing the configuration of structure 1b in the manufacturing process.

[0192] Structure 1b comprises structure 1a shown in Figure 22(a), a plurality of wires 30, and a plurality of threads 40.

[0193] Multiple wires 30 are arranged in parallel on the lower surface 12 of the first base member 10 so as to overlap with multiple conductive elastic bodies 20. Here, three sets of wire groups G1, each consisting of two wires 30 extending in the Y-axis direction, are arranged on the lower surface 12, for a total of six wires 30 arranged on the lower surface 12. The wire groups G1 are arranged at predetermined intervals in the X-axis direction. The two wires 30 of wire groups G1 are also arranged at predetermined intervals in the X-axis direction. The wires 30 are arranged between the first base member 10 and the second base member 70 in the state in which the load sensor 1 has been assembled, as will be described later.

[0194] As shown in Figure 27(a), the wire 30 is composed of a conductor wire 31 and a dielectric 32 that covers the surface of the conductor wire 31. In this embodiment, the cross-section of the wire 30 perpendicular to the direction in which the wire 30 extends has a circular shape with a diameter R1. The conductor wire 31 is a linear conductive member. The conductor wire 31 is made of a metallic material such as copper. The conductor wire 31 may be composed of a core wire made of glass and a conductive layer formed on its surface, or it may be composed of a core wire made of resin and a conductive layer formed on its surface, etc. The conductor wire 31 may also be a stranded wire made of wires made of a conductive metallic material twisted together. The dielectric 32 has electrical insulating properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc.

[0195] The negative Y-axis end of the conductor wire 31 is not covered by the dielectric 32, and this end is connected to the detection circuit. Two conductor wires 31 included in one wire group G1 are connected to each other in the detection circuit. Alternatively, two conductor wires 31 included in one wire group G1 may be connected to each other within the load sensor 1, and one of these conductor wires 31 may be connected to the detection circuit.

[0196] The multiple threads 40 have electrical insulating properties. Each thread 40 extends in the X-axis direction at the position of the gap between adjacent conductive elastic bodies 20, and sews multiple wires 30 to the first base member 10.

[0197] Figure 23 is a schematic perspective view showing the configuration of multiple load distribution plates 50, multiple adhesive members 60, structure 1b, and second base member 70 in the manufacturing process.

[0198] The load distribution plate 50 is a rigid, substantially flat plate-shaped member. In plan view, the load distribution plate 50 has a rectangular shape. In plan view, the load distribution plate 50 is positioned near the intersection of one wire group G1 and one conductive elastic body 20 (within the range of element section A, described later).

[0199] As described later, the load distribution plate 50 is positioned to evenly distribute the load applied to the upper surface 51 of the load distribution plate 50 to the corresponding element portion A. Therefore, it is preferable that the load distribution plate 50 has high rigidity. Specifically, the load distribution plate 50 has higher rigidity than the first base member 10. Furthermore, it is preferable that the load distribution plate 50 has rigidity that allows it to be treated as a rigid body in practical terms. For example, the thickness of the load distribution plate 50 is set to 0.1 mm or more, and the bending rigidity of the load distribution plate 50 is set to be greater than 10 MPa. The load distribution plate 50 is made of a highly rigid non-conductive resin material or a non-conductive metal. However, if the mass of the load distribution plate 50 is large, it will be as if a load has been applied to the element portion A in advance, so it is preferable that the mass of the load distribution plate 50 be small. Therefore, in this embodiment, the load distribution plate 50 is made of an acrylic resin.

[0200] Figure 24 is a schematic perspective view showing the configuration of the load distribution plate 50.

[0201] The load distribution plate 50 is divided in the X-axis direction into a first region R11 and two second regions R12 on either side thereof. The lower surface 52 of the load distribution plate 50 is composed of one flat surface 52a formed in the first region R11 and two inclined surfaces 52b formed in the two second regions R12, respectively. The flat surface 52a is a surface parallel to the X-Y plane. The inclined surfaces 52b are flat surfaces that are tilted when a surface parallel to the X-Y plane is rotated around the Y axis. The upper surface 51 of the load distribution plate 50 is parallel to the X-Y plane. Side surfaces 53 parallel to the Y-Z plane are formed at the positive X-axis and negative X-axis ends of the load distribution plate 50.

[0202] The thickness of the load distribution plate 50 in the first region R11 is constant. The thickness of the load distribution plate 50 in the second region R12 decreases as it moves away from the first region R11. The load distribution plate 50 has a shape in which the end of a flat plate-like member is cut out so that an inclined surface 52b is formed.

[0203] Returning to Figure 23, the adhesive member 60 adheres the flat surface 52a of the lower surface 52 of the load distribution plate 50 to the upper surface 11 of the first base member 10. The adhesive member 60 is, for example, double-sided tape or adhesive. In this embodiment, the adhesive member 60 is positioned over the entire flat surface 52a of the lower surface 52 and adheres the entire flat surface 52a to the upper surface 11 of the first base member 10.

[0204] The second base member 70 is a flat plate-shaped member having insulating properties and high rigidity. In a plan view, the second base member 70 has the same shape as the first base member 10. The thickness of the second base member 70 is constant. The upper surface 71 (the surface on the positive Z-axis side) and the lower surface 72 (the surface on the negative Z-axis side) of the second base member 70 are both parallel to the X-Y plane. The upper surface 71 is the opposing surface facing the first base member 10. The second base member 70 is made of, for example, a resin material having insulating properties and rigidity.

[0205] As shown in Figure 23, each load distribution plate 50 is fixed via an adhesive member 60 to a position corresponding to the element A, which will be described later. In this embodiment, nine load distribution plates 50 are arranged in a matrix. The lower surface 12 of the first base member 10 is placed opposite the upper surface 71 of the second base member 70, and the vicinity of the outer circumference of the first base member 10 and the vicinity of the outer circumference of the second base member 70 are sewn together with thread (not shown). In this way, the load sensor 1 is completed as shown in Figure 25.

[0206] Figure 25 is a schematic perspective view showing the configuration of the load sensor 1.

[0207] When using the load sensor 1, the load distribution plate 50 is oriented upward (positive Z-axis), and the second base member 70 is oriented downward (negative Z-axis), so that the negative Z-axis direction is vertically downward, i.e., the direction of gravity. In this case, the upper surface 51 of the load distribution plate 50 (upper surface of the load sensor 1) becomes the surface to which the load is applied, and the lower surface 72 of the second base member 70 (lower surface of the load sensor 1) is placed on the installation surface. A base plate may also be placed on the lower surface 72 of the second base member 70.

[0208] Figure 26 is a schematic plan view showing the configuration of the load sensor 1.

[0209] In Figure 26, for convenience, the area of ​​element A is shown by a long dashed line, and the adhesive member 60 is shown by halftone dots surrounded by a dashed line.

[0210] The load sensor 1 has multiple element sections A arranged in a matrix in a plan view. The load sensor 1 in Figure 26 has a total of nine element sections A arranged in the X-axis direction and the Y-axis direction. One element section A corresponds to a region including the intersection point of the conductive elastic body 20 and the wire group G1 arranged below the conductive elastic body 20. One load distribution plate 50 is installed on the upper surface 11 of the first base member 10 so as to extend to the range of the corresponding element section A in a plan view. A predetermined gap is provided between adjacent element sections A. In a plan view, the range of the outer circumference shape formed by the nine element sections A corresponds to the load detection surface of the load sensor 1.

[0211] When the lower surface of the load sensor 1 is placed on a predetermined mounting surface and a load is applied to the upper surface of the load sensor 1, the capacitance between the conductive elastic body 20 and the conductor wire 31 changes in the element A to which the load is applied, and the load applied to the element A is detected based on this capacitance.

[0212] Figures 27(a) and 27(b) schematically show the cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane.

[0213] Figure 27(a) shows the state without any load applied, and Figure 27(b) shows the state with a load applied. In Figures 27(a) and (b), the lower surface 72 on the negative Z-axis side of the second base member 70 is placed on the mounting surface.

[0214] As shown in Figure 27(a), one element A is composed of a first base member 10, a conductive elastic body 20, two wires 30, and a second base member 70 near the intersection of one conductive elastic body 20 and one wire group G1. In this embodiment, one element A has two pressure-sensitive parts A1 whose capacitance changes with load.

[0215] The pressure-sensitive section A1 comprises at least a portion of the conductive elastic body 20, at least a portion of the conductor wire 31, and at least a portion of the dielectric 32, and is configured such that the capacitance between the conductive elastic body 20 and the conductor wire 31 changes with load. The pressure-sensitive section A1 is composed of a portion of element A in which the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 can change with load. Specifically, the width W1 of the pressure-sensitive section A1 in the X-axis direction is the length over which the conductive elastic body 20 can contact the wire 30, and if the diameter of the wire 30 is R1, the width W1 of the pressure-sensitive section A1 is πR1. The length of the pressure-sensitive section A1 in the Y-axis direction is the same as the length of element A in the Y-axis direction and coincides with the width of the conductive elastic body 20 in the Y-axis direction. The pressure-sensitive section A1 is located in the first region R11 of the load distribution plate 50.

[0216] As shown in Figure 27(a), when no load is applied to element A, the conductive elastic body 20 and the wire 30 are in contact, and the conductive elastic body 20 is almost undeformed. From this state, as shown in Figure 27(b), when a load is applied downward to the upper surface 51 of the load distribution plate 50, the conductive elastic body 20 deforms due to the wire 30. At this time, the wire 30 is enveloped by the conductive elastic body 20, and the contact area between the wire 30 and the conductive elastic body 20 increases. As a result, the capacitance between the conductor wire 31 and the conductive elastic body 20 changes. The potential reflecting the change in capacitance based on the two pressure-sensitive parts A1 within element A is measured in the detection circuit, and the load applied to element A is calculated. In other words, element A detects the load applied to element A based on the capacitance of the pressure-sensitive parts A1.

[0217] Incidentally, in load detection by the load sensor 1, it is desirable to properly detect the load applied to element A even when a load is applied locally to element A. However, in the case where a slope 52b is not formed on the lower surface 52 of the load distribution plate 50 and the load distribution plate 50 is flat (Comparative Example 3), depending on the location of the load applied locally to element A, it may not be possible to properly detect the load.

[0218] Specifically, in Comparative Example 3, when a load is applied locally to the first region R11 of the load distribution plate 50, this load is distributed by the load distribution plate 50 and easily transmitted to each pressure-sensitive part A1, so the load can be detected properly. However, when a load is applied locally to the second region R12 of the load distribution plate 50, this load causes the load distribution plate 50 to rotate with respect to the wire 30 closest to the second region R12, and the load distribution plate 50 tilts so that the load application position becomes lower. As a result, at relatively low loads, the end of the first base member 10 comes into contact with the second base member 70, the rate of increase in the contact area between the conductive elastic body 20 and the wire 30 decreases, and the sensitivity of the element A decreases. Consequently, in Comparative Example 3, when a high load is applied locally, the capacitance value differs depending on the application position, which may result in the inability to properly detect the load.

[0219] In contrast, in this embodiment, as shown in Figure 24, the thickness of the load distribution plate 50 in the second region R12 is set to be smaller than the thickness of the load distribution plate 50 in the first region R11. Also, as shown in Figure 27(a), the lower surface 52 (inclined surface 52b) of the load distribution plate 50 in the second region R12 is spaced further away from the second base member 70 than the lower surface 52 (flat surface 52a) of the load distribution plate 50 in the first region R11. As a result, even if a load is applied locally to the second region R12 of the load distribution plate 50, the lower surface 52 of the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. Therefore, even when a load is applied to the second region R12, the same sensitivity as when a load is applied to the first region R11 can be achieved. Thus, the load can be properly detected up to a relatively high load range.

[0220] The effects of this embodiment will be explained below with reference to the simulation results.

[0221] Figure 28(a) shows the conditions for verifying the relationship between load and capacitance in the simulation of Comparative Example 3. Figure 28(b) shows the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 4.

[0222] As shown in Figure 28(a), in the simulation configuration of Comparative Example 3, four wires 30 are arranged at equal intervals between the first base member 10 and the second base member 70, and a load distribution plate 50 is placed on the upper surface of the first base member 10 in the area of ​​element A that spans the two central wires 30. The load distribution plate 50 has a flat plate shape, and the upper surface 51 and lower surface 52 are the same size. The entire lower surface 52 of the load distribution plate 50 is fixed to the upper surface of the first base member 10, as shown by the thick line.

[0223] As shown in Figure 28(b), in the simulation configuration of Embodiment 4, compared to Comparative Example 3 in Figure 28(a), inclined surfaces 52b are formed at the positive and negative X-axis ends of the load distribution plate 50. The positive and negative X-axis ends of the plane 52a are spaced apart in the X-axis direction from the positive and negative X-axis ends of the upper surface 51, respectively.

[0224] In this simulation, the change in the contact area between the conductive elastic body 20 and the wire 30 in response to a load is verified by the change in the contact area between the first base member 10 and the wire 30. Therefore, for convenience, the conductive elastic body 20 was omitted in this simulation.

[0225] As shown in Figures 28(a) and (b), the thickness T1 of the first base member 10 and the thickness T2 of the second base member 70 were both set to 0.5 mm. The width W2 in the X-axis direction of the first base member 10 and the second base member 70 was set to 24 mm. The diameter R1 of the wire 30 was set to 0.26 mm. In the load distribution plate 50, the thickness T3 was set to 0.4 mm and the width W3 in the X-axis direction was set to 10 mm. The width W4 in the X-axis direction of the inclined surface 52b was set to 1.6 mm. The configuration in Figures 28(a) and (b) was made to continue infinitely in the Y-axis direction, and the length of the element section A in the X-axis and Y-axis directions was set to 10 mm.

[0226] In the first base member 10, the material model was set to Neo-Hookean, with an initial shear modulus of 0.5 MPa and a compressibility factor of zero. In the wire 30 and the second base member 70, the modulus of elasticity was set to 200 GPa and Poisson's ratio to 0.3. In the load distribution plate 50, the modulus of elasticity was set to 3000 MPa and Poisson's ratio to 0.33, the same as for polyethylene terephthalate (PET).

[0227] In Comparative Example 3 and Embodiment 4, a load was applied to the upper surface of element A near the X-axis end. The load application region had a width of 1 mm in the X-axis direction and an infinite width in the Y-axis direction. However, in this simulation, instead of actually applying a load, the load distribution plate 50 was displaced in the negative Z-axis direction within the load application region.

[0228] In this simulation, for each step of the displacement corresponding to the load described above, the contact area between the two wires 30 corresponding to element A and the first base member 10 was calculated. The first base member 10 was then treated as a conductive elastic body 20, and the capacitance was approximated from the calculated contact area.

[0229] Figures 29(a) and 29(b) show the state of the load distribution plate 50 and the first base member 10 in relation to this simulation.

[0230] Figures 29(a) and 29(b) show the strain state of the first base member 10 in the configurations of Comparative Example 3 and Embodiment 4, respectively, represented by color. For convenience, the strain state in Figures 29(a) and 29(b) is represented in grayscale, with lighter colors indicating areas of greater strain. Figures 29(a) and 29(b) also show the load Ld used to apply the load (displacement).

[0231] As shown in Figures 29(a) and 29(b), in both Comparative Example 3 and Embodiment 4, the load distribution plate 50 at the applied load position moved in the negative Z-axis direction, and the load distribution plate 50 and the first base member 10 rotated around the wire 30 on the positive X-axis side.

[0232] In this case, as shown in Figure 29(a), in Comparative Example 3, at the positive X-axis end of the load distribution plate 50, the load distribution plate 50 and the first base member 10 move integrally in the negative Z-axis direction, and the first base member 10 is pressed against the second base member 70. As a result, near the contact point between the first base member 10 and the second base member 70 located below the load Ld, the applied load is supported by the second base member 70 via the first base member 10, and compressive stress is generated in the first base member 10, as shown in light gray. In this case, since the load is supported by the second base member 70, the contact area between the first base member 10 and the wire 30 does not increase appropriately in response to the increase in load, and the rate of increase in the contact area decreases.

[0233] On the other hand, as shown in Figure 29(b), in Embodiment 4, since a slope 52b is provided at the end of the load distribution plate 50 on the positive X-axis side, the first base member 10 located below the slope 52b is not pressed down by the load distribution plate 50. As a result, the applied load is not transmitted to the first base member 10 near the contact point between the first base member 10 and the second base member 70 located below the load Ld, and no compressive stress is generated in the first base member 10. In this case, since the load is not supported by the second base member 70, the contact area between the first base member 10 and the wire 30 increases appropriately in response to the increase in load, and the decrease in the rate of increase of the contact area can be suppressed.

[0234] Figure 30 is a graph showing the relationship between load and capacitance in this simulation.

[0235] In Figure 30, the horizontal axis shows the displacement of the load distribution plate 50 converted into load, and the vertical axis shows the capacitance calculated from the contact area between the first base member 10 and the wire 30. In the graph of Figure 30, each plot consisting of load and capacitance is connected by a line.

[0236] In both Comparative Example 3 and Embodiment 4, the capacitance increases in response to the increase in load. However, in Comparative Example 3, when the load exceeds 0.2 N, the increase in the contact area slows down, and the increase in capacitance in response to the increase in load slows down. As a result, in a configuration like Comparative Example 3, where the load distribution plate 50 does not have an inclined surface 52b, it is possible to properly detect the load in a low load range (approximately 0 N to 0.2 N in Figure 30), but there is a risk that the load may not be properly detected in a high load range (0.2 N or more in Figure 30). On the other hand, in Embodiment 4, even in a load range exceeding 0.2 N, the capacitance in response to the load increases reliably compared to Comparative Example 3. As a result, in a configuration like Embodiment 4, where the load distribution plate 50 has an inclined surface 52b, it is possible to properly detect the load in a wide load range.

[0237] <Effects of Embodiment 4> According to Embodiment 4, the following effects are achieved.

[0238] As shown in Figures 23 and 27(a), the load sensor 1 comprises a sheet-like first base member 10 that is elastic and has an upper surface 11 (first upper surface) and a lower surface 12 (first lower surface) on the opposite side of the upper surface 11 (first upper surface); a second base member 70 positioned opposite the lower surface 12 (first lower surface) of the first base member 10; a pressure-sensitive part A1 positioned between the first base member 10 and the second base member 70, whose capacitance changes with load; and a load distribution plate 50 having an upper surface 51 (second upper surface) and a lower surface 52 (second lower surface) on the opposite side of the upper surface 51 (second upper surface), with at least a part of the lower surface 52 (second lower surface) fixed to the upper surface 11 (first upper surface) of the first base member 10. When viewed in plan from the upper surface 11 (first upper surface) to the lower surface 12 (first lower surface) of the first base member 10, the load distribution plate 50 is divided into a first region R11 and second regions R12 on both sides thereof, and the pressure-sensitive part A1 is located in the first region R11. The thickness of the load distribution plate 50 in the second regions R12 on both sides is set to be smaller than the thickness of the load distribution plate 50 in the first region R11, and the lower surfaces 52 (second lower surfaces) of the load distribution plate 50 in the second regions R12 on both sides are spaced further from the second base member 70 than the lower surfaces 52 (second lower surfaces) of the load distribution plate 50 in the first region R11.

[0239] With this configuration, when a load is applied to any of the second regions R12, the second region R12 is displaced in the direction of the applied load, causing the load distribution plate 50 to tilt. However, since the lower surface 52 of the load distribution plate 50 in the second region R12 is further away from the second base member 70 than the lower surface 52 of the load distribution plate 50 in the first region R11, the lower surface 52 of the load distribution plate 50 in the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. Therefore, the load applied locally to the load distribution plate 50 (for example, the load applied to the second region R12) can be properly detected up to a relatively high load range.

[0240] As shown in Figure 24, the lower surface 52 (second lower surface) of the load distribution plate 50 in the second region R12 is inclined such that it approaches the upper surface 51 (second upper surface) of the load distribution plate 50 as it moves away from the first region R11.

[0241] This configuration allows for maintaining the strength of the load distribution plate 50 in the second region R12 while suppressing the lower surface 52 of the load distribution plate 50 in the second region R12 from pressing against the upper surface 71 of the second base member 70.

[0242] As shown in Figure 27(a), the pressure-sensitive section A1 comprises a conductive elastic body 20 formed on the lower surface 12 (first lower surface) of the first base member 10, a conductor wire 31 positioned opposite the lower surface 12 (first lower surface) of the first base member 10 and extending in the Y-axis direction (one direction), and a dielectric 32 positioned between the conductive elastic body 20 and the conductor wire 31. The second base member 70 supports the conductor wire 31.

[0243] This configuration allows for a simpler construction of the pressure-sensitive section A1. Furthermore, with this configuration, when a load is applied to any of the second regions R12, the second region R12 is displaced in the direction of the applied load, causing the load distribution plate 50 to rotate around the conductor wire 31 extending in the Y-axis direction. In this case as well, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced apart from the second base member 70, the lower surface 52 of the load distribution plate 50 in the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. As a result, locally applied loads on the load distribution plate 50 (for example, loads applied to the second region R12) can be properly detected up to a relatively high load range.

[0244] As shown in Figure 27(a), the dielectric 32 is installed so as to cover the surface of the conductor wire 31.

[0245] With this configuration, the dielectric 32 can be placed between the conductive elastic body 20 and the conductor wire 31 simply by covering the surface of the conductor wire 31 with the dielectric 32.

[0246] As shown in Figures 26 and 27(a), an element unit A is defined which comprises a first base member 10, a second base member 70, and a pressure-sensitive part A1, and detects the applied load based on the capacitance of the pressure-sensitive part A1. Multiple element units A are arranged in a line when viewed from the upper surface 11 (first upper surface) to the lower surface 12 (first lower surface) of the first base member 10, and a load distribution plate 50 is provided on each of the multiple element units A.

[0247] With this configuration, the load detection surface of the load sensor 1 can be widened, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element A.

[0248] As shown in Figure 26, multiple element units A are arranged in a matrix.

[0249] With this configuration, a two-dimensional (matrix-like) load distribution can be detected on the load detection surface of the load sensor 1.

[0250] As shown in Figure 23, the load sensor 1 further includes an adhesive member 60 for fixing the load distribution plate 50 and the element part A.

[0251] With this configuration, the load distribution plate 50 can be fixed to the element section A with a simple structure.

[0252] <Modification Example 8> In Embodiment 4, as shown in Figure 23, the adhesive member 60 was arranged across the entire plane 52a of the lower surface 52 of the load distribution plate 50. However, there may be areas between adjacent wires 30 (areas that do not overlap with the wires 30 in a plan view) where the adhesive member 60 is not arranged. In this case, only the area of ​​the plane 52a where the adhesive member 60 is arranged may be parallel to the X-Y plane.

[0253] Figure 31 is a schematic perspective view showing the configuration of the multiple load distribution plates 50, multiple adhesive members 60, structure 1b, and second base member 70 in the manufacturing process according to this modified example.

[0254] In this modified example, compared to Embodiment 4 shown in Figure 23, two adhesive members 60 are arranged for one load distribution plate 50. The length of the adhesive member 60 in the Y-axis direction in this modified example is the same as the length of the adhesive member 60 in the Y-axis direction in Embodiment 4, and the length of the adhesive member 60 in the X-axis direction in this modified example is shorter than the length of the adhesive member 60 in the X-axis direction in Embodiment 4. The adhesive member 60 adheres the flat surface 52a of the lower surface 52 of the load distribution plate 50 to the upper surface 11 of the first base member 10.

[0255] Figure 32 is a schematic perspective view showing the configuration of the load distribution plate 50 in this modified example.

[0256] In this modified example, compared to Embodiment 4 shown in Figure 24, a recess 52f extending in the Y-axis direction is formed at the center of the plane 52a in the X-axis direction. The bottom surface of the recess 52f (the surface parallel to the X-Y plane) is located in the positive Z-axis direction relative to the plane 52a. The lower surface 52 of the load distribution plate 50 in this modified example is composed of two planes 52a, two slopes 52b adjacent to the planes 52a, and a recess 52f between the two planes 52a.

[0257] Figure 33 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0258] In this modified example, the placement range of one adhesive member 60 is limited to the vicinity of one pressure-sensitive section A1. Specifically, the placement range of one adhesive member 60 is equal to the range of one pressure-sensitive section A1, and the width of the adhesive member 60 in the X-axis direction is the same as the width W1 of the pressure-sensitive section A1 in the X-axis direction (see Figure 34(a)). In addition, each adhesive member 60 is positioned such that its centerline in the X-axis direction overlaps with the wire 30.

[0259] Figures 34(a) and 34(b) schematically show the cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to this modified example.

[0260] As shown in Figure 34(a), when no load is applied to element A, the conductive elastic body 20 and the wire 30 are in contact, similar to Embodiment 4, and the conductive elastic body 20 is almost undeformed. From this state, as shown in Figure 34(b), when a load is applied downward to the upper surface 51 of the load distribution plate 50, the wire 30 is enveloped by the conductive elastic body 20, similar to Embodiment 4, and the contact area between the wire 30 and the conductive elastic body 20 increases.

[0261] In this modified example, since the first base member 10 and the load distribution plate 50 are not fixed between two adjacent adhesive members 60 in the X-axis direction, the first base member 10 in this region flexes downward away from the load distribution plate 50. As a result, compared to embodiment 4 shown in Figure 27(b), the wire 30 is further encased in the conductive elastic body 20, and the contact area between the wire 30 and the conductive elastic body 20 is further increased. Also, since a 52f is provided on the lower surface 52 of the load distribution plate 50, the first base member 10 is reliably separated from the load distribution plate 50 in areas other than the pressure-sensitive part A1, so that the conductive elastic body 20 can further cover the area around the wire 30.

[0262] <Effects of Modification Example 8> As shown in Figures 34(a) and (b), the placement range of the adhesive member 60 is limited to the vicinity of the pressure-sensitive part A1.

[0263] In this configuration, the load distribution plate 50 and the first base member 10 are not fixed by the adhesive member 60 in areas other than the pressure-sensitive part A1. As a result, when a load is applied, the first base member 10 separates from the load distribution plate 50 in areas other than the pressure-sensitive part A1, and the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 can more easily cover the area around the wire 30. Consequently, the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 is more likely to increase, thereby increasing the sensitivity of the load sensor 1.

[0264] As shown in Figures 34(a) and 34(b), in a plan view, the adhesive member 60 is not positioned between adjacent pressure-sensitive parts A1.

[0265] With this configuration, when a load is applied, the first base member 10 reliably separates from the load distribution plate 50 between adjacent pressure-sensitive parts A1, making it easier for the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 to cover the area around the wire 30. This increases the sensitivity of the element A.

[0266] In plan view, the area in which the adhesive member 60 is placed may be less than or equal to the area of ​​the pressure-sensitive part A1. This allows the conductive elastic body 20 to further cover the area around the wire 30 when a load is applied. Also, as in Embodiment 4, a recess 52f does not need to be provided on the lower surface 52 of the load distribution plate 50. In this case as well, by not placing the adhesive member 60 in an intermediate position between the two pressure-sensitive parts A1, the contact area between the conductive elastic body 20 and the wire 30 can be increased. Furthermore, in Embodiment 4 as well, the adhesive member 60 does not need to be placed between adjacent pressure-sensitive parts A1.

[0267] <Example of modification 9> In Embodiment 4, a slope 52b is provided on the lower surface 52 of the load distribution plate 50 in the second region R12, but the invention is not limited to this, and a shape other than a slope 52b may be provided.

[0268] For example, the lower surface 52 of the second region R12 may be provided with the shape shown in Figures 35(a) to 36(b). In the modified examples shown in Figures 35(a) to 36(b), the load distribution plate 50 is configured such that the lower surface 52 of the second region R12 is further away from the second base member 70 than the lower surface 52 of the first region R11. In the modified examples shown in Figures 35(b) to 36(b), the lower surface 52 of the second region R12 is inclined to approach the upper surface 51 of the load distribution plate 50 as it moves away from the first region R11.

[0269] In the modified example shown in Figure 35(a), a step 52d is provided on the lower surface 52 of the second region R12. This step 52d is composed of a plane parallel to the Y-Z plane located at the boundary between the first region R11 and the second region R12, and a plane parallel to the X-Y plane located in the second region R12. In the second region R12, the thickness of the load distribution plate 50 is constant.

[0270] In the modified example shown in Figure 35(a), a step 52d is provided on the lower surface 52 (second lower surface) of the load distribution plate 50 in the second region R12. With this configuration, the lower surface 52 of the second region R12 can be separated from the second base member 70 by a larger margin compared to Embodiment 4. Therefore, the pressing of the lower surface 52 of the load distribution plate 50 in the second region R12 against the upper surface 71 of the second base member 70 can be further suppressed.

[0271] In the modified example shown in Figure 35(a), a single step 52d is provided in the second region R12, but a step 52d consisting of two or more steps may also be provided.

[0272] In the modified example shown in Figure 35(b), two inclined surfaces 52b are provided on the lower surface 52 of one second region R12. Both inclined surfaces 52b are flat planes, and the boundary between the two inclined surfaces 52b extends in the Y-axis direction. The angle of the inclined surface 52b closer to the first region R11 with respect to the upper surface 11 of the first base member 10 is smaller than the angle of the inclined surface 52b farther from the first region R11 with respect to the upper surface 11 of the first base member 10. In this modified example, the boundary between the two inclined surfaces 52b protrudes in the negative Z-axis direction, resulting in a greater thickness of the second region R12 compared to Embodiment 4. This increases the strength of the second region R12.

[0273] In the modified example shown in Figure 36(a), a curved surface 52e having the side shape of an elliptical cylinder with a generatrix extending in the Y-axis direction is provided on the lower surface 52 of the second region R12. In the cross-section along the X-Z plane, the curved surface 52e protrudes in the negative Z-axis direction. In this modified example as well, the thickness of the second region R12 is greater than in embodiment 4, thus increasing the strength of the second region R12.

[0274] In the modified example shown in Figure 36(b), a curved surface 52e having the side shape of an elliptical cylinder with a generatrix extending in the Y-axis direction is provided on the lower surface 52 of the second region R12. However, in this modified example, the curved surface 52e is concave in the positive Z-axis direction in the cross-section of the X-Z plane. As a result, in this modified example, the lower surface 52 of the second region R12 can be spaced much further away from the second base member 70 compared to embodiment 4.

[0275] In the modified examples shown in Figures 36(a) and (b), the curved surface 52e was the side shape of an elliptical cylinder, but the shape of the curved surface 52e is not limited to this and may be any other shape. Also, in the modified examples shown in Figures 36(a) and (b), the curved surface 52e was composed of one type of curved surface, but it may be composed of two or more types of curved surfaces. Furthermore, the shape of the lower surface 52 of the second region R12 may be composed of a curved surface and a flat surface.

[0276] <Modification Example 10> In Embodiment 4, the outer end of the pressure-sensitive part A1 in the X-axis direction coincided with the boundary between the first region R11 and the second region R12, but the pressure-sensitive part A1 can be placed in the first region R11. For example, as shown in Figure 37(a), the outer end of the pressure-sensitive part A1 in the X-axis direction may be located inside the element A beyond the boundary between the first region R11 and the second region R12.

[0277] In this modified example as well, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced apart from the second base member 70, the lower surface 52 of the load distribution plate 50 in the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. As a result, locally applied loads (for example, loads applied to the second region R12) can be properly detected up to a relatively high load range.

[0278] However, in order to detect a load locally applied to the outside of the pressure-sensitive part A1 up to a relatively high load range, it is preferable that the slope 52b of the second region R12 is formed up to the outer end of the pressure-sensitive part A1 in the X-axis direction, as in Embodiment 4.

[0279] <Modification Example 11> In Embodiment 4, the dielectric 32 was arranged to cover the surface of the conductor wire 31, but the dielectric 32 is not limited to this, and may be placed between the conductive elastic body 20 and the conductor wire 31. For example, as shown in Figure 37(b), it may be placed on the lower surface (the negative Z-axis side) of the conductive elastic body 20.

[0280] In this modified example, the dielectric 32 is formed on the lower surface of the conductive elastic body 20, compared to Embodiment 4 shown in Figure 27(a). Alternatively, the dielectric 32 may be formed on the lower surface 12 of the first base member 10 so as to span across the lower surfaces of all conductive elastic bodies 20.

[0281] In this case as well, the capacitance of the pressure-sensitive part A1 changes in accordance with the load applied to the upper surface 51 of the load distribution plate 50, so the load applied to the element part A can be detected, similar to Embodiment 4. Furthermore, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced apart from the second base member 70, locally applied loads (for example, loads applied to the second region R12) can be properly detected up to a relatively high load range.

[0282] <Modification Example 12> In Embodiment 4, one element A had two pressure-sensitive parts A1, but as shown in Figure 38, one element A may have one pressure-sensitive part A1. In this case, one conductive elastic body 20 and one conductor wire 31 intersect in one element A. In this modification example as well, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced further from the second base member 70 than the lower surface 52 of the load distribution plate 50 in the first region R11, the load applied locally to the load distribution plate 50 can be properly detected up to a relatively high load range.

[0283] <Example of modification 13> In Embodiment 4, one load distribution plate 50 was arranged in one element section A so as to extend to the area corresponding to the element section A, but two or more load distribution plates 50 may be arranged.

[0284] Figure 39 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0285] In this modified example, compared to Embodiment 4 shown in Figure 26, two load distribution plates 50 are arranged for one element section A. The two load distribution plates 50 arranged for one element section A are aligned in the Y-axis direction with a gap between them and have the same shape. The length of the load distribution plate 50 in the X-axis direction in this modified example is the same as the length of the load distribution plate 50 in the X-axis direction in Embodiment 4, and the length of the load distribution plate 50 in the Y-axis direction in this modified example is shorter than the length of the load distribution plate 50 in the Y-axis direction in Embodiment 4. In one element section A, both the load distribution plate 50 on the positive Y-axis side and the load distribution plate 50 on the negative Y-axis side are arranged to straddle the two pressure-sensitive sections A1 (see Figure 27(a)) within the element section A.

[0286] In this modified example as well, the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced further from the second base member 70 than the lower surface 52 of the load distribution plate 50 in the first region R11, so that the load locally applied to the load distribution plate 50 can be properly detected up to a relatively high load range. Also, compared to the case where only one load distribution plate 50 is arranged as in Embodiment 4, the area of ​​each load distribution plate 50 is smaller, so the rigidity required for the load distribution plate 50 can be set lower.

[0287] Alternatively, the two load distribution plates 50 arranged in one element section A may be positioned side by side in the X-axis direction with a gap between them. In this case, each load distribution plate 50 is divided into a first region R11 corresponding to one pressure-sensitive section A1 and second regions R12 on both sides thereof, similar to the modified example 12 in Figure 38.

[0288] <Embodiment 5> In Embodiment 4, the pressure-sensitive portion A1 was formed by the overlapping of the conductive elastic body 20 and the conductor wire 31 via the dielectric 32, but the pressure-sensitive portion A1 may be formed by other configurations. In Embodiment 5, the pressure-sensitive portion A1 is formed by the overlapping of the electrode and the protruding conductive elastic body via the dielectric.

[0289] Figure 40 is a schematic diagram showing a cross-section of the element portion A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to Embodiment 5. The following describes a configuration that differs from Embodiment 4.

[0290] In Embodiment 5, the load sensor 1 is provided with one element A. A conductive elastic body 110 is formed on the lower surface 12 of the first base member 10. The conductive elastic body 110 is made of the same material as the conductive elastic body 20 in Embodiment 4. On the lower surface of the conductive elastic body 110, in a plan view, a plurality of protrusions 111 are integrally formed in the first region R11 of the load distribution plate 50. The protrusions 111 have a frustoconical shape in which the diameter in the X-Y plane decreases as they extend downward. An electrode 120 is formed on the upper surface 71 of the second base member 70. The electrode 120 is made of a conductive metal (for example, aluminum). A dielectric 130 is formed on the upper surface of the electrode 120. The dielectric 130 is made of the same material as the dielectric 32 in Embodiment 4.

[0291] When a load is applied, the protrusions 111 of the conductive elastic body 110 contract in accordance with the load, increasing the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130. This changes the capacitance between the conductive elastic body 110 and the electrode 120. The potential reflecting this change in capacitance is then measured in the detection circuit, and the load applied to element A is calculated.

[0292] The pressure-sensitive portion A1 is composed of a part of element A in which the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130 can change with load. In a plan view, the pressure-sensitive portion A1 is a region with a width W5 centered on the projection 111.

[0293] In Embodiment 5, when a load is applied to any of the second regions R12, the second region R12 is displaced in the direction of the applied load, causing the load distribution plate 50 to tilt. At this time, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced apart from the second base member 70, the lower surface 52 of the load distribution plate 50 in the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. As a result, locally applied loads (for example, loads applied to the second region R12) can be properly detected up to a relatively high load range.

[0294] <Embodiment 6> In Embodiment 4, the contact area between the two electrodes (conductive elastic body 20 and conductor wire 31) via the dielectric 32 increased due to the deformation of the first base member 10 and the conductive elastic body 20 by the application of a load. However, the invention is not limited to this, and the contact area between the two electrodes via the dielectric may also increase due to deformation of other parts.

[0295] Figure 41 is a schematic diagram showing a cross-section of the element portion A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to Embodiment 6. The following describes a configuration that differs from Embodiment 4.

[0296] In Embodiment 6, a second base member 210 is provided in place of the second base member 70. The second base member 210 is made of the same material as the first base member 10. A plurality of conductive elastic bodies 220 are formed on the upper surface 211 of the second base member 210 with gaps in the X-axis direction. The lower surface 212 of the second base member 210 is installed on the mounting surface. A plurality of conductive elastic bodies 230 are formed on the lower surface 12 of the first base member 10 with gaps in the Y-axis direction. The conductive elastic bodies 220 and 230 are made of the same material as, for example, the conductive elastic body 20 in Embodiment 4. A layered dielectric 240 is provided between the conductive elastic bodies 220 and 230. The dielectric 240 is made of, for example, a resin material having electrical insulation and elasticity.

[0297] When a load is applied, the first base member 10, the second base member 210, the conductive elastic bodies 220 and 230, and the dielectric 240 deform, increasing the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240. This changes the capacitance between the conductive elastic body 220 and the conductive elastic body 230. The potential reflecting this change in capacitance is measured in the detection circuit, and the load applied to element A is calculated.

[0298] The pressure-sensitive section A1 is composed of a portion of element A in which the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240 can change with load. The width of the pressure-sensitive section A1 in the X-axis direction is W6.

[0299] In Embodiment 6, when a load is applied to any of the second regions R12, the second region R12 is displaced in the direction of the applied load, causing the load distribution plate 50 to tilt. At this time, since the lower surface 52 of the load distribution plate 50 in the second region R12 is spaced apart from the second base member 70, the lower surface 52 of the load distribution plate 50 in the second region R12 does not press against the upper surface 71 of the second base member 70 up to a relatively high load range. As a result, locally applied loads (for example, loads applied to the second region R12) can be properly detected up to a relatively high load range.

[0300] <Other Modification Examples> In embodiments 4 to 6 and modifications 8 to 13 described above, a single-layer load distribution plate 50 was placed in element section A, but two or more layers of load distribution plates 50 may be stacked and arranged.

[0301] In embodiments 4 to 6 and modified examples 8 to 13, one or two load distribution plates 50 are arranged in a single element section A so as to extend over the area corresponding to that element section A, but three or more load distribution plates 50 may be arranged.

[0302] In Embodiment 4 and Modification Examples 8 to 13 described above, three element sections A were arranged in the X-axis direction and the Y-axis direction, respectively. However, the number of element sections A arranged in the X-axis direction and the Y-axis direction may be one, two, or four or more.

[0303] In Embodiment 4 and Modifications 8 to 13 described above, one wire group G1 included one or two wires 30, but it is not limited to this, and one wire group G1 may include three or more wires 30. That is, one element A may have three or more pressure-sensitive parts A1.

[0304] In embodiments 5 and 6 described above, one element A had three pressure-sensitive parts A1, but it may have one, two, or four or more pressure-sensitive parts A1.

[0305] In Embodiment 4 and Modifications 8 to 13 described above, the conductive elastic body 20 was placed only on the lower surface 12 of the first base member 10, but it may also be placed on both the lower surface 12 of the first base member 10 and the upper surface 71 of the second base member 70. In this case, in Modification 11, the dielectric 32 is also placed on the upper surface of the conductive elastic body 20 placed on the upper surface 71 of the second base member 70.

[0306] In Embodiment 4 and Modification Examples 8 to 13 described above, the cross-sectional shape of the conductor wire 31 was circular, but it is not limited to this, and other shapes such as ellipse or pseudo-circular may also be used.

[0307] In Embodiment 4 and Modifications 8 to 13 described above, the direction in which the conductive elastic body 20 extends and the direction in which the wire 30 extends are perpendicular to each other. However, the angle between these directions may be an angle other than 90°. That is, the wire 30 may intersect the conductive elastic body 20 at an oblique angle.

[0308] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0309] (Note) The above description of embodiments discloses the following technologies.

[0310] (Technical 12) A sheet-like first base member having elasticity and having a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; and a load-distributing plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member, wherein when viewed in plan from the first upper surface to the first lower surface of the first base member, the load-distributing plate is divided into a first region and second regions on both sides thereof, the pressure-sensitive part is disposed in the first region, the thickness of the load-distributing plate in the second regions on both sides is set to be smaller than the thickness of the load-distributing plate in the first region, and the second lower surfaces of the load-distributing plate in the second regions on both sides are spaced further from the second base member than the second lower surface of the load-distributing plate in the first region. A load sensor characterized by the following features.

[0311] According to this technology, when a load is applied to any of the second regions, the second region is displaced in the direction of the applied load, causing the load distribution plate to tilt. However, because the second lower surface of the load distribution plate in the second region is further away from the second base member than the second lower surface of the load distribution plate in the first region, the second lower surface of the load distribution plate in the second region does not press against the upper surface of the second base member up to a relatively high load range. Therefore, locally applied loads can be properly detected up to a relatively high load range.

[0312] (Technical 13) A load sensor as described in Technical 12, characterized in that the second lower surface of the load distribution plate in the second region is inclined such that it approaches the second upper surface of the load distribution plate as it moves away from the first region.

[0313] This technology makes it possible to maintain the strength of the load distribution plate in the second region while suppressing the second lower surface of the load distribution plate in the second region from pressing against the upper surface of the second base member.

[0314] (Technical 14) A load sensor according to Technical 12 or 13, characterized in that a step is provided on the second lower surface of the load distribution plate in the second region.

[0315] This technology further suppresses the pressing of the second lower surface of the load distribution plate against the upper surface of the second base member in the second region.

[0316] (Technical 15) A load sensor according to any one of Technical 12 to 14, wherein the pressure-sensitive part comprises a conductive elastic body formed on the first lower surface of the first base member, a conductor wire arranged opposite to the first lower surface of the first base member and extending in one direction, and a dielectric material arranged between the conductive elastic body and the conductor wire, and the second base member supports the conductor wire.

[0317] This technology allows for a simpler construction of the pressure-sensitive section. Furthermore, with this technology, when a load is applied to any of the second regions, the second region is displaced in the direction of the applied load, causing the load distribution plate to rotate around a conductor wire extending in one direction. In this case as well, since the second lower surface of the load distribution plate in the second region is separated from the second base member, the second lower surface of the load distribution plate in the second region does not press against the upper surface of the second base member up to a relatively high load range. As a result, the load applied locally to the load distribution plate can be properly detected up to a relatively high load range.

[0318] (Technical 16) A load sensor as described in Technical 15, characterized in that the dielectric is installed so as to cover the surface of the conductor wire.

[0319] According to this technology, a dielectric material can be placed between a conductive elastic material and a conductor wire simply by coating the surface of the conductor wire with a dielectric material.

[0320] (Technical 17) A load sensor according to any one of Technical 12 to 16, wherein an element unit is defined which comprises the first base member, the second base member, and the pressure-sensitive unit, and which detects an applied load based on the capacitance of the pressure-sensitive unit, and a plurality of the element units are arranged in a line when viewed from the first upper surface to the first lower surface of the first base member, and one or more of the load distribution plates are provided on each of the plurality of element units.

[0321] This technology allows for an expanded load detection surface of the load sensor, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element.

[0322] (Technical 18) A load sensor as described in Technical 17, characterized in that a plurality of the element portions are arranged in a matrix.

[0323] This technology allows for the detection of a two-dimensional (matrix-like) load distribution on the load detection surface of a load sensor.

[0324] <Embodiment 7> Figure 42(a) is a schematic perspective view showing the configuration of structure 1a in the manufacturing process.

[0325] The structure 1a comprises a first base member 10, a plurality of conductive elastic bodies 20, and a plurality of wirings 20a.

[0326] The first base member 10 is an elastic, sheet-like member. The first base member 10 has a rectangular shape in plan view. The thickness of the first base member 10 is constant. The upper surface 11 (the positive Z-axis side) and the lower surface 12 (the negative Z-axis side) of the first base member 10 are both parallel to the X-Y plane. The lower surface 12 is positioned downwards during assembly and is the opposing surface that faces the second base member 70, which will be described later. The first base member 10 is insulating and is made of, for example, a non-conductive resin material or a non-conductive rubber material.

[0327] Multiple conductive elastic bodies 20 are installed in parallel on the lower surface 12 of the first base member 10. Here, three conductive elastic bodies 20 are arranged in the Y-axis direction. Each conductive elastic body 20 has a long, strip-like shape in the X-axis direction and is arranged in the Y-axis direction with a predetermined gap between them. The width, length, and thickness of the three conductive elastic bodies 20 are the same. The conductive elastic bodies 20 are conductive members with elasticity. One end of the wiring 20a is connected to the conductive elastic body 20, and the other end of the wiring 20a is connected to the detection circuit.

[0328] The conductive elastic body 20 is composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, carbon (C) is used as the conductive filler in the conductive elastic body 20. However, the filler used in the conductive elastic body 20 is not limited to these, and may be made of other conductive materials.

[0329] The conductive elastic body 20 is formed on the lower surface 12 of the first base member 10 by printing methods such as screen printing, gravure printing, flexographic printing, offset printing, and gravure offset printing. These printing methods allow for the formation of the conductive elastic body 20 on the lower surface 12 of the first base member 10 with a thickness of approximately 0.001 mm to 0.5 mm. However, the method of forming the conductive elastic body 20 is not limited to printing methods.

[0330] Furthermore, an electrode pattern with a width in the Y-axis direction narrower than the conductive elastic body 20 may be arranged between the lower surface 12 of the first base member 10 and the conductive elastic body 20. This electrode pattern is also composed of a resin material and a conductive filler dispersed therein, or a rubber material and a conductive filler dispersed therein. For example, Ag (silver) is used as the conductive filler in this electrode pattern. This electrode pattern is also formed on the lower surface 12 of the first base member 10 by the printing method described above.

[0331] Figure 42(b) is a schematic perspective view showing the configuration of structure 1b in the manufacturing process.

[0332] Structure 1b comprises structure 1a shown in Figure 42(a), a plurality of wires 30, and a plurality of threads 40.

[0333] Multiple wires 30 are arranged in parallel on the lower surface 12 of the first base member 10 so as to overlap with multiple conductive elastic bodies 20. Here, three sets of wire groups G1, each consisting of two wires 30 extending in the Y-axis direction, are arranged on the lower surface 12, for a total of six wires 30 arranged on the lower surface 12. The wire groups G1 are arranged at predetermined intervals in the X-axis direction. The two wires 30 of wire groups G1 are also arranged at predetermined intervals in the X-axis direction. The wires 30 are arranged between the first base member 10 and the second base member 70 in the state in which the load sensor 1 has been assembled, as will be described later.

[0334] As shown in Figure 47(a), the wire 30 is composed of a conductor wire 31 and a dielectric 32 that covers the surface of the conductor wire 31. The conductor wire 31 is a linear conductive member. The conductor wire 31 is made of a metallic material such as copper. The conductor wire 31 may be composed of a glass core wire and a conductive layer formed on its surface, or it may be composed of a resin core wire and a conductive layer formed on its surface, etc. The conductor wire 31 may also be a stranded wire made of wires made of a conductive metallic material twisted together. The dielectric 32 has electrical insulating properties and is made of, for example, a resin material, a ceramic material, a metal oxide material, etc.

[0335] The negative Y-axis end of the conductor wire 31 is not covered by the dielectric 32, and this end is connected to the detection circuit. Two conductor wires 31 included in one wire group G1 are connected to each other in the detection circuit. Alternatively, two conductor wires 31 included in one wire group G1 may be connected to each other within the load sensor 1, and one of these conductor wires 31 may be connected to the detection circuit.

[0336] The multiple threads 40 have electrical insulating properties. Each thread 40 extends in the X-axis direction at the position of the gap between adjacent conductive elastic bodies 20, and sews multiple wires 30 to the first base member 10.

[0337] Figure 43 is a schematic perspective view showing the configuration of structure 1c in the manufacturing process.

[0338] Structure 1c comprises structure 1b and guide 80.

[0339] The guide 80 is constructed by forming a plurality of openings 83 and a plurality of grooves 84 in a rigid, flat plate-shaped member. The guide 80 has a frame shape in which a plurality of openings 83 are formed.

[0340] The opening 83 penetrates the guide 80 in the Z-axis direction and is square in plan view. The opening 83 is formed near the position where one wire group G1 and one conductive elastic body 20 intersect in plan view (the range of element part A described later). In this embodiment, nine openings 83 are formed in a matrix arrangement. The groove 84 is formed on the lower surface 82 of the guide 80 at a position that overlaps with the thread 40 in plan view. In this embodiment, two grooves 84 are formed extending in the X-axis direction.

[0341] The guide 80 is fixed to the structure 1b by bonding the lower surface 82 of the guide 80 and the upper surface 11 of the first base member 10 with an adhesive member 61 (see Figure 47(a)). The adhesive member 61 is, for example, double-sided tape or adhesive. In this embodiment, the adhesive member 61 is positioned at the center in the width direction of the frame portion that constitutes the lower surface 82 of the guide 80. In addition, the stitching of the thread 40 that protrudes toward the upper surface 11 of the first base member 10 is accommodated in the groove 84 of the guide 80. As a result, the lower surface 82 of the guide 80 and the upper surface 11 of the first base member 10 are bonded in close contact without being obstructed by the thread 40.

[0342] Figure 44 is a schematic perspective view showing the configuration of multiple load distribution plates 50, multiple adhesive members 62, structure 1c, and second base member 70 in the manufacturing process.

[0343] The load distribution plate 50 is a rigid, flat plate-shaped member. The load distribution plate 50 has a rectangular parallelepiped shape and a rectangular shape in plan view. The thickness of the load distribution plate 50 is constant. The upper surface 51 (the positive Z-axis side) and the lower surface 52 (the negative Z-axis side) of the load distribution plate 50 are both parallel to the X-Y plane. The four sides 53 of the load distribution plate 50 are all planes perpendicular to the X-Y plane. In plan view, the load distribution plate 50 is positioned near the intersection of one wire group G1 and one conductive elastic body 20 (the range of element section A, described later).

[0344] As described later, the load distribution plate 50 is positioned to evenly distribute the load applied to the upper surface 51 of the load distribution plate 50 to the corresponding element portion A. Therefore, it is preferable that the load distribution plate 50 has high rigidity. Specifically, the load distribution plate 50 has higher rigidity than the first base member 10. Furthermore, it is preferable that the load distribution plate 50 has rigidity that allows it to be treated as a rigid body in practical terms. For example, the thickness of the load distribution plate 50 is set to 0.1 mm or more, and the bending rigidity of the load distribution plate 50 is set to be greater than 10 MPa. The load distribution plate 50 is made of a highly rigid non-conductive resin material or a non-conductive metal. However, if the mass of the load distribution plate 50 is large, it will be as if a load has been applied to the element portion A in advance, so it is preferable that the mass of the load distribution plate 50 be small. Therefore, in this embodiment, the load distribution plate 50 is made of an acrylic resin.

[0345] The thickness of the load distribution plate 50 is set to be at least greater than the thickness of the guide 80. Detailed settings for the thicknesses of the load distribution plate 50 and the guide 80 will be explained later with reference to Figures 48(a) and (b). Also, in plan view, the opening 83 of the guide 80 is made to be slightly larger than the load distribution plate 50. This allows the load distribution plate 50 to move in the Z-axis direction while it is housed in the opening 83, and suppresses its movement in the X-Y plane.

[0346] The adhesive member 62 adheres the lower surface 52 of the load distribution plate 50 to the upper surface 11 of the first base member 10. The adhesive member 62 is, for example, double-sided tape or adhesive. In this embodiment, the adhesive member 62 is positioned in the area of ​​the pressure-sensitive section A1, which will be described later, in a plan view. That is, an area is provided between adjacent wires 30 (an area that does not overlap with the wires 30 in a plan view) where the adhesive member 62 is not positioned.

[0347] The second base member 70 is a flat plate-shaped member having insulating properties and high rigidity. In a plan view, the second base member 70 has the same shape as the first base member 10. The thickness of the second base member 70 is constant. The upper surface 71 (the surface on the positive Z-axis side) and the lower surface 72 (the surface on the negative Z-axis side) of the second base member 70 are both parallel to the X-Y plane. The upper surface 71 is the opposing surface facing the first base member 10. The second base member 70 is made of, for example, a resin material having insulating properties and rigidity.

[0348] As shown in Figure 44, each load distribution plate 50 is housed in the opening 83 of the guide 80 from above and fixed to the upper surface 11 of the first base member 10 via an adhesive member 62. In this embodiment, nine load distribution plates 50 are arranged in a matrix. The lower surface 12 of the first base member 10 is then placed opposite the upper surface 71 of the second base member 70, and the outer circumference of the first base member 10 and the outer circumference of the second base member 70 are sewn together with thread (not shown). Thus, as shown in Figure 45, the load sensor 1 is completed.

[0349] Figure 45 is a schematic perspective view showing the configuration of the load sensor 1.

[0350] When using the load sensor 1, the load distribution plate 50 is oriented upward (positive Z-axis), and the second base member 70 is oriented downward (negative Z-axis), so that the negative Z-axis direction is vertically downward, i.e., the direction of gravity. In this case, the upper surface 51 of the load distribution plate 50 (upper surface of the load sensor 1) becomes the surface to which the load is applied, and the lower surface 72 of the second base member 70 (lower surface of the load sensor 1) is placed on the installation surface. A base plate may also be placed on the lower surface 72 of the second base member 70.

[0351] Figure 46 is a schematic plan view showing the configuration of the load sensor 1.

[0352] In Figure 46, for convenience, the area of ​​element A is shown by a long dashed line, the guide 80 is shown by a high-density halftone dot, and the area of ​​the adhesive member 62 is shown by a halftone dot enclosed by a dashed line.

[0353] The load sensor 1 has multiple element sections A arranged in a matrix in a plan view. The load sensor 1 in Figure 46 has a total of nine element sections A arranged in the X-axis direction and the Y-axis direction. One element section A corresponds to a region including the intersection point of the conductive elastic body 20 and the wire group G1 arranged below the conductive elastic body 20. One load distribution plate 50 is installed on the upper surface 11 of the first base member 10 so as to extend to the range of the corresponding element section A in a plan view. The range of the outer circumference shape formed by the nine element sections A in a plan view corresponds to the load detection surface of the load sensor 1.

[0354] When the lower surface of the load sensor 1 is placed on a predetermined mounting surface and a load is applied to the upper surface of the load sensor 1, the capacitance between the conductive elastic body 20 and the conductor wire 31 changes in the element A to which the load is applied, and the load applied to the element A is detected based on this capacitance.

[0355] Figures 47(a) and 47(b) schematically show the cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane.

[0356] Figure 47(a) shows the state without any load applied, and Figure 47(b) shows the state with a load applied. In Figures 47(a) and (b), the lower surface 72 on the negative Z-axis side of the second base member 70 is placed on the mounting surface.

[0357] As shown in Figure 47(a), one element A is composed of a first base member 10, a conductive elastic body 20, two wires 30, and a second base member 70 near the intersection of one conductive elastic body 20 and one wire group G1. In this embodiment, one element A has two pressure-sensitive parts A1 whose capacitance changes with load.

[0358] The pressure-sensitive section A1 comprises at least a portion of the conductive elastic body 20, at least a portion of the conductor wire 31, and at least a portion of the dielectric 32, and is configured such that the capacitance between the conductive elastic body 20 and the conductor wire 31 changes with load. The pressure-sensitive section A1 is composed of a portion of element A in which the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 can change with load. Specifically, the width W1 of the pressure-sensitive section A1 in the X-axis direction is the length over which the conductive elastic body 20 can contact the wire 30, and if the diameter of the wire 30 is R1, the width W1 of the pressure-sensitive section A1 is πR1. The length of the pressure-sensitive section A1 in the Y-axis direction is the same as the length of element A in the Y-axis direction and coincides with the width of the conductive elastic body 20 in the Y-axis direction.

[0359] As shown in Figure 47(a), when no load is applied to element A, the conductive elastic body 20 and the wire 30 are in contact, and the conductive elastic body 20 is almost undeformed. From this state, as shown in Figure 47(b), when a load is applied downward to the upper surface 51 of the load distribution plate 50, the conductive elastic body 20 deforms due to the wire 30. At this time, the wire 30 is enveloped by the conductive elastic body 20, and the contact area between the wire 30 and the conductive elastic body 20 increases. As a result, the capacitance between the conductor wire 31 and the conductive elastic body 20 changes. The potential reflecting the change in capacitance based on the two pressure-sensitive parts A1 within element A is measured in the detection circuit, and the load applied to element A is calculated. In other words, element A detects the load applied to element A based on the capacitance of the pressure-sensitive parts A1.

[0360] By the way, in load detection by the load sensor 1, it is desirable to properly detect the load applied to element A even when a load is applied locally to element A. However, in the case where the guide 80 is not provided (comparative example), depending on the location of the load applied locally to element A, it may not be possible to properly detect the load.

[0361] Specifically, in the comparative example, when a load is applied locally near the center of the load distribution plate 50, this load is distributed by the load distribution plate 50 and easily transmitted to each pressure-sensitive part A1, allowing the load to be detected properly. However, when a load is applied locally to the end of the load distribution plate 50 in the X-axis direction, this load causes the load distribution plate 50 to rotate with respect to the wire 30 closest to the load application position, causing the load distribution plate 50 to tilt so that the load application position becomes lower. As a result, at relatively low loads, the end of the first base member 10 comes into contact with the second base member 70, reducing the rate of increase in the contact area between the conductive elastic body 20 and the wire 30, and decreasing the sensitivity of the element A. Consequently, in the comparative example, when a high load is applied locally, the capacitance value differs depending on the application position, which may result in improper load detection.

[0362] In contrast, in this embodiment, as shown in Figure 44, a guide 80 is provided, and the four sides 53 of the load distribution plate 50 are surrounded by the opening 83 of the guide 80. Also, in a plan view, the opening 83 of the guide 80 is slightly larger than the outer shape of the load distribution plate 50 (the area surrounded by the four sides 53). As a result, as shown in Figures 48(a) and (b), a small gap GP is created between the sides 53 of the load distribution plate 50 and the inner surface 83a of the opening 83 of the guide 80.

[0363] As the guide 80 is provided in this manner, even if a load is applied locally near the end of the load distribution plate 50, as shown in Figure 48(b), the rotation of the load distribution plate 50 is suppressed, and the load distribution plate 50 moves smoothly in the Z-axis direction. As a result, the load applied to the element A is transmitted to the pressure-sensitive part A1 almost evenly, and the detection sensitivity can be maintained at a high level up to a relatively high load range. In other words, even when a load is applied to the end of the element A, the same sensitivity as when the load is applied to the center of the element A can be achieved. Therefore, the load can be properly detected up to a relatively high load range.

[0364] Furthermore, when the load to be detected is placed on the upper surface 51 of the load distribution plate 50, the height position of the load distribution plate 50 must be set as shown below in order to properly detect the load of the load.

[0365] As shown in Figure 48(a), the upper surface 71 of the second base member 70 is used as the reference for vertical height, and the positive Z-axis direction is defined as the positive height direction. The height of the upper surface 51 of the load distribution plate 50 is defined as H1, and the height of the upper surface 81 of the guide 80 is defined as H2. Starting from the unloaded state in Figure 48(a), when the load distribution plate 50 moves downward due to the load, as shown in the loaded state in Figure 48(b), for example, the load distribution plate 50 sinks downward by H3. At this time, if the upper surface 81 of the guide 80 is higher than the upper surface 51 of the load distribution plate 50, the load will hit the upper surface 81 of the guide 80, and the load of the load will not be properly transmitted to the load distribution plate 50.

[0366] Therefore, the sizes of the load distribution plate 50 and the guide 80 are set such that the height H1 of the upper surface 51 of the load distribution plate 50 when a load of any size is applied is higher than the height H2 of the upper surface 81 of the guide 80 when there is no load. In other words, the sizes of the load distribution plate 50 and the guide 80 are set so that the upper surface 51 is higher than the upper surface 81 no matter what kind of load is placed on it. This ensures that the load of the load is properly transmitted to the load distribution plate 50.

[0367] Next, the effects of this embodiment will be explained with reference to the simulation results.

[0368] Figure 49(a) shows the conditions for verifying the relationship between load and capacitance in the simulations of Comparative Examples 4 and 5. Figure 49(b) shows the conditions for verifying the relationship between load and capacitance in the simulation of Embodiment 7.

[0369] As shown in Figure 49(a), in the simulation configurations of Comparative Examples 4 and 5, four wires 30 are arranged at equal intervals between the first base member 10 and the second base member 70, and a load distribution plate 50 is positioned on the upper surface of the first base member 10 in the area of ​​element A that spans the two central wires 30. The load distribution plate 50 has a flat plate shape. The entire lower surface 52 of the load distribution plate 50 is fixed to the upper surface of the first base member 10, as shown by the thick line.

[0370] As shown in Figure 49(b), in the simulation configuration of Embodiment 7, guides 80 are positioned on the positive and negative sides of the X-axis of the load distribution plate 50, respectively, compared to Comparative Examples 4 and 5 in Figure 49(a). In this simulation, no gap GP is provided between the load distribution plate 50 and the guides 80, allowing the load distribution plate 50 to move smoothly in the vertical direction while in contact with the guides 80.

[0371] In this simulation, the change in the contact area between the conductive elastic body 20 and the wire 30 in response to a load is verified by the change in the contact area between the first base member 10 and the wire 30. Therefore, for convenience, the conductive elastic body 20 was omitted in this simulation.

[0372] As shown in Figures 49(a) and (b), the thickness T1 of the first base member 10 and the thickness T2 of the second base member 70 were both set to 0.5 mm. The width W2 in the X-axis direction of the first base member 10 and the second base member 70 was set to 24 mm. The diameter R1 of the wire 30 was set to 0.26 mm. The width W3 in the X-axis direction of the load distribution plate 50 was set to 10 mm. The thickness T31 of the load distribution plate 50 shown in Figure 49(a) was set to 0.4 mm, and the thickness T32 of the load distribution plate 50 shown in Figure 49(b) was set to 1.5 mm. As shown in Figure 49(b), in the guide 80, the width W4 in the X-axis direction was set to 2 mm, and the thickness T4 was set to 1.2 mm. The width W11 in the X-axis direction of the adhesive member 61 was set to 0.2 mm. The width W12 in the X-axis direction of the adhesive member 62 was set to 0.4 mm, which is shorter than the width W1 (=πR1). The configurations in Figures 49(a) and (b) are assumed to extend infinitely in the Y-axis direction, and the length of element A in the X-axis and Y-axis directions is set to 10 mm.

[0373] In the first base member 10, the material model was set to Neo-Hookean, with an initial shear modulus of 0.5 MPa and a compressibility factor of zero. In the wire 30, the second base member 70, and the guide 80, the modulus of elasticity was set to 200 GPa and the Poisson's ratio to 0.3. In the load distribution plate 50, the modulus of elasticity was set to 3000 MPa and the Poisson's ratio was set to 0.33, the same as that of polyethylene terephthalate (PET).

[0374] In Comparative Example 4, a load was applied to the entire upper surface of the load distribution plate 50, and the load was evenly distributed over the upper surface area of ​​the first base member 10 within the range of the load distribution plate 50. Here, since the load distribution plate 50 can be considered substantially rigid, a localized load applied to the center of the load distribution plate 50 in the X-axis direction can also be treated in the simulation as if the load were evenly distributed over the upper surface area of ​​the first base member 10 within the range of the load distribution plate 50. In Comparative Example 5 and Embodiment 7, a load was applied near the X-axis end of the upper surface 51 of the load distribution plate 50. For the load application region in Comparative Example 5 and Embodiment 7, the width in the X-axis direction was set to 1 mm, and the width in the Y-axis direction was set to infinite. However, in this simulation, instead of actually applying a load, the load distribution plate 50 was displaced in the negative Z-axis direction within the load application region.

[0375] In this simulation, for each step of the displacement corresponding to the load described above, the contact area between the two wires 30 corresponding to element A and the first base member 10 was calculated. The first base member 10 was then treated as a conductive elastic body 20, and the capacitance was approximated from the calculated contact area.

[0376] Figures 50(a) to (c) show the state of the load distribution plate 50 and the first base member 10 in relation to this simulation.

[0377] Figures 50(a) to (c) show the strain state of the first base member 10 in the configurations of Comparative Examples 4 and 5 and Embodiment 7, respectively, represented by color. For convenience, the strain state in Figures 50(a) to (c) is represented in grayscale, with lighter colors indicating areas of greater strain. Figures 50(a) to (c) also show the load Ld used to apply the load (displacement).

[0378] As shown in Figure 50(a), in Comparative Example 4, the load from the loaded material Ld is evenly applied to the first base member 10 in the area corresponding to the load distribution plate 50. In this way, if the applied load is evenly distributed to the two pressure-sensitive parts A1 (see Figure 47(b)), it can be seen that the contact area between the first base member 10 and the wire 30 increases appropriately as the load increases.

[0379] As shown in Figure 50(b), in Comparative Example 5, the load distribution plate 50 at the applied load position moved in the negative Z-axis direction, and the load distribution plate 50 and the first base member 10 rotated around the wire 30 on the positive X-axis side. At this time, in Comparative Example 5, at the X-axis positive end of the load distribution plate 50, the load distribution plate 50 and the first base member 10 moved integrally in the negative Z-axis direction, and the first base member 10 was pressed against the second base member 70. As a result, near the contact point between the first base member 10 and the second base member 70 located below the load Ld, the applied load was supported by the second base member 70 via the first base member 10, and compressive stress was generated in the first base member 10, as shown in light gray. In this case, because the load is supported by the second base member 70, the contact area between the first base member 10 and the wire 30 does not increase appropriately in response to the increase in load, and the rate of increase in the contact area decreases.

[0380] On the other hand, as shown in Figure 50(c), in Embodiment 7, guides 80 are installed on the positive and negative sides of the X-axis of the load distribution plate 50, respectively. Therefore, the rotation of the load distribution plate 50, as in Comparative Example 5 in Figure 50(b), is suppressed, while the load distribution plate 50 can move in the Z-axis direction. As a result, similar to Comparative Example 4 in Figure 50(a), the load applied near the end in the X-axis direction is distributed to the two pressure-sensitive parts A1. Therefore, the contact area between the first base member 10 and the wire 30 increases appropriately in response to the increase in load, and the decrease in the rate of increase of the contact area is suppressed.

[0381] Figure 51 is a graph showing the relationship between load and capacitance in this simulation.

[0382] In Figure 51, the horizontal axis shows the displacement of the load distribution plate 50 converted into load, and the vertical axis shows the capacitance calculated from the contact area between the first base member 10 and the wire 30. In the graph of Figure 51, each plot consisting of load and capacitance is connected by a line.

[0383] In Comparative Example 4, the applied load is distributed almost equally to the two pressure-sensitive parts A1, resulting in an ideal graph where capacitance increases in proportion to the increase in load. In contrast, in Comparative Example 5, although capacitance increases in proportion to the increase in load, when the load exceeds approximately 0.1 N, the increase in contact area slows down, and the increase in capacitance in proportion to the increase in load slows down. This shows that in a configuration without a guide 80, as in Comparative Example 5, the load can be properly detected in the low load range (approximately 0 N to 0.13 N in Figure 51), but the load detection sensitivity decreases in the high load range (0.13 N or more in Figure 51), and there is a risk that the load may not be properly detected.

[0384] On the other hand, in Embodiment 7, even in the range where the load exceeds 0.13 N, the capacitance corresponding to the load increases reliably, similar to the ideal Comparative Example 4. This shows that in a configuration with a guide 80 as in Embodiment 7, the load can be properly detected over a wide range of loads.

[0385] As shown in Figure 49(b), in Embodiment 7, the position where the load distribution plate 50 is fixed to the first base member 10 is limited to the vicinity of the pressure-sensitive part A1. As a result, as shown in Figure 50(c), in Embodiment 7, the first base member 10 bends downward away from the load distribution plate 50 between two adjacent wires 30 in the X-axis direction. Therefore, compared to Comparative Example 4, the wires 30 are further encased in the conductive elastic body 20, increasing the contact area between the wires 30 and the conductive elastic body 20. Thus, providing a region between the two wires 30 where the load distribution plate 50 is not adhered, as in Embodiment 7, can improve the sensitivity of the load.

[0386] Furthermore, in this simulation, as shown in Figure 50(c), a localized load was applied to the X-axis end of the load distribution plate 50 in the configuration of Embodiment 7. However, it is expected that even if a localized load is applied to the Y-axis end of the load distribution plate 50, good load detection will be possible, similar to that of the ideal comparative example 4 in Figure 51. In other words, in Embodiment 7, no matter where a localized load is applied to the load distribution plate 50, the load distribution plate 50 moves downward while maintaining its horizontal position. As a result, the detection result will be almost the same regardless of where the same load is applied, and the detected load will be almost the same as that of the ideal comparative example 4 in Figure 51.

[0387] <Effects of Embodiment 7> According to Embodiment 7, the following effects are achieved.

[0388] As shown in Figures 44 and 47(a), the load sensor 1 comprises a sheet-like first base member 10 which is elastic and has an upper surface 11 (first upper surface) and a lower surface 12 (first lower surface) on the opposite side of the upper surface 11 (first upper surface), a second base member 70 positioned opposite the lower surface 12 (first lower surface) of the first base member 10, a pressure-sensitive part A1 positioned between the first base member 10 and the second base member 70 whose capacitance changes with load, and an upper surface 51 (second upper surface) and the opposite side of the upper surface 51 (second upper surface) The load distribution plate 50 has a lower surface 52 (second lower surface) on the opposite side, and at least a part of the lower surface 52 (second lower surface) is fixed to the upper surface 11 (first upper surface) of the first base member 10. The load distribution plate 50 is provided with a guide 80 that guides the load distribution plate 50 in the vertical direction, when the direction from the upper surface 51 (second upper surface) of the load distribution plate 50 to the lower surface 52 (second lower surface) and the direction from the lower surface 52 (second lower surface) to the upper surface 51 (second upper surface) of the load distribution plate 50 are defined as the vertical direction, thereby suppressing the tilting of the load distribution plate 50 in at least the vertical direction.

[0389] With this configuration, even when a load is locally applied to the end of the load distribution plate 50, the load distribution plate 50 is guided in the vertical direction, and tilting of the load distribution plate 50 in at least the vertical direction is suppressed. In other words, even when a load is locally applied to the end of the load distribution plate 50, the guide 80 guides the load distribution plate 50 substantially only in the vertical direction, suppressing at least the change in the angle of the load distribution plate 50 in the vertical direction. As a result, the situation in which the first base member 10 is supported by the second base member 70 due to tilting of the load distribution plate 50 is avoided, and therefore, even when a load is locally applied to the end of the load distribution plate 50, the detection sensitivity can be maintained at a relatively high load range. Thus, loads locally applied to the load distribution plate 50 can be properly detected up to a relatively high load range.

[0390] The guide 80 further suppresses the movement of the load distribution plate 50 in the inward direction of the upper surface 51 (second upper surface).

[0391] With this configuration, regardless of where a load is applied locally on the load distribution plate 50, the movement of the load distribution plate 50 inward on the upper surface 51, i.e., the parallel and rotational movement of the load distribution plate 50 within the upper surface 51, is suppressed. As a result, loads can be properly detected up to a relatively high load range, regardless of where a load is applied locally on the load distribution plate 50.

[0392] As shown in Figures 44 and 47(a) and (b), the load distribution plate 50 has a rectangular upper surface 51 (second upper surface) and a rectangular lower surface 52 (second lower surface), as well as four side surfaces 53, and the guide 80 guides each of the four side surfaces 53 of the load distribution plate 50 in the vertical direction.

[0393] This configuration allows for smooth vertical guidance of the load distribution plate 50 while suppressing its tilt.

[0394] As shown in Figure 44, the guide 80 is installed on the upper surface 11 (first upper surface) of the first base member 10.

[0395] This configuration allows for easy installation of the guide 80.

[0396] As shown in Figures 48(a) and (b), the second base member 70 has a sheet shape with an upper surface 71 (third upper surface) facing the lower surface 12 (first lower surface) of the first base member 10, and the guide 80 has an upper surface 81 (fourth upper surface) which is the planar shape furthest from the first base member 10 in the vertical direction. When the upper surface 71 (third upper surface) of the second base member 70 is used as the reference for height in the vertical direction, and the direction from the second base member 70 toward the first base member 10 is defined as the positive height direction, the height of the upper surface 51 (second upper surface) of the load distribution plate 50 when a load of any size is applied is higher than the height of the upper surface 81 (fourth upper surface) of the guide 80 in the unloaded state.

[0397] With this configuration, the upper surface 51 of the load distribution plate 50 does not move to a position lower than the upper surface 81 of the guide 80 when a load is detected. Therefore, it is possible to avoid a situation where the loaded material comes into contact with the upper surface 81 of the guide 80, making it impossible to properly detect the applied load.

[0398] As shown in Figures 46 and 47(a), an element unit A is defined which comprises a first base member 10, a second base member 70, and a pressure-sensitive part A1, and which detects the applied load based on the capacitance of the pressure-sensitive part A1. Multiple element units A are arranged side by side in a plan view in the vertical direction, and a load distribution plate 50 is provided on each of the multiple element units A.

[0399] With this configuration, the load detection surface of the load sensor 1 can be widened, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element A.

[0400] As shown in Figure 46, multiple element units A are arranged in a matrix.

[0401] With this configuration, a two-dimensional (matrix-like) load distribution can be detected on the load detection surface of the load sensor 1.

[0402] As shown in Figure 46, the guide 80 is integrated to correspond to each of the multiple element sections A. That is, the frame-shaped configuration that forms the opening 83 in which the multiple element sections A are housed is integrated to constitute the guide 80.

[0403] This configuration eliminates the need to install a guide for each of the multiple element sections A, thus simplifying the configuration of the load sensor 1.

[0404] As shown in Figure 47(a), the pressure-sensitive section A1 comprises a conductive elastic body 20 formed on the lower surface 12 (first lower surface) of the first base member 10, a conductor wire 31 positioned opposite the lower surface 12 (first lower surface) of the first base member 10 and extending in the Y-axis direction (one direction), and a dielectric 32 positioned between the conductive elastic body 20 and the conductor wire 31. The second base member 70 supports the conductor wire 31.

[0405] This configuration allows for a simpler design of the pressure-sensitive section A1.

[0406] As shown in Figure 47(a), the dielectric 32 is installed so as to cover the surface of the conductor wire 31.

[0407] With this configuration, the dielectric 32 can be placed between the conductive elastic body 20 and the conductor wire 31 simply by covering the surface of the conductor wire 31 with the dielectric 32.

[0408] As shown in Figure 44, the load sensor 1 further includes an adhesive member 62 for fixing the load distribution plate 50 and the element part A.

[0409] With this configuration, the load distribution plate 50 can be fixed to the element section A with a simple structure.

[0410] As shown in Figures 47(a) and (b), the placement range of the adhesive member 62 is limited to the vicinity of the pressure-sensitive part A1.

[0411] In this configuration, the load distribution plate 50 and the first base member 10 are not fixed by the adhesive member 62 in areas other than near the pressure-sensitive part A1. As a result, when a load is applied, the first base member 10 separates from the load distribution plate 50 in areas other than near the pressure-sensitive part A1, and the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 can more easily cover the area around the wire 30. Consequently, the contact area between the conductive elastic body 20 and the conductor wire 31 via the dielectric 32 is more likely to increase, thereby increasing the sensitivity of the load sensor 1.

[0412] As shown in Figures 47(a) and 47(b), in a plan view, the adhesive member 62 is not positioned between adjacent pressure-sensitive parts A1.

[0413] With this configuration, when a load is applied, the first base member 10 reliably separates from the load distribution plate 50 between adjacent pressure-sensitive parts A1, making it easier for the conductive elastic body 20 formed on the lower surface 12 of the first base member 10 to cover the area around the wire 30. This increases the sensitivity of the element A.

[0414] Furthermore, in a plan view, the area in which the adhesive member 62 is placed may be less than or equal to the area of ​​the pressure-sensitive part A1. This makes it easier for the conductive elastic body 20 to further cover the area around the wire 30 when a load is applied.

[0415] <Example of modification 14> In Embodiment 7, the guide 80 was configured to guide all of the load distribution plates 50, but the configuration of the guide 80 is not limited to this, and it is sufficient that each load distribution plate 50 is guided in the vertical direction by the guide.

[0416] Figure 52 is a schematic perspective view showing the configuration of the multiple load distribution plates 50, multiple adhesive members 62, structure 1c, and second base member 70 in the manufacturing process according to this modified example.

[0417] In this modified example, compared to Embodiment 7 shown in Figure 44, multiple guides 90 are arranged instead of the guide 80. In this modified example, 16 guides 90 are arranged. In a plan view, the four central guides 90 have a plus sign shape, the four guides 90 located at the corners of the first base member 10 have an L shape, and the other guides 90 have a T shape. The guides 90 are made of the same material as the guides 80 in Embodiment 7, and the thickness of the guides 90 is also the same as that of the guides 80 in Embodiment 7. In a plan view, only the area near the center of the guides 90 is fixed to the upper surface 11 of the first base member 10 by the adhesive member 61 (see Figure 55(a)). The side surfaces 91 of the multiple guides 90 form the corner portions of the opening 83 of the guide 80 in Embodiment 7.

[0418] Figure 53 is a schematic perspective view showing the configuration of the load distribution plate 50.

[0419] The lower surface 52 of the load distribution plate 50 in this modified example is composed of two planes 52a parallel to the X-Y plane, four slopes 52b adjacent to planes 52a, and one plane 52c located on the positive Z-axis side of plane 52a and parallel to the X-Y plane. Planes 52a and 52c extend in the Y-axis direction. Plane 52a and the pair of slopes 52b flanking plane 52a form a ridge shape extending in the Y-axis direction on the lower surface 52. In plan view, the range of one plane 52a is equal to the arrangement range of one adhesive member 62 shown in Figure 52.

[0420] Figure 54 is a schematic plan view showing the configuration of the load sensor 1 in this modified example.

[0421] In this modified example, the sides 91 of the four guides 90, which are positioned adjacent to one load distribution plate 50, are located near the four corners of the load distribution plate 50, and the sides 53 of the load distribution plate 50 face the corresponding sides of the four guides 90.

[0422] Figures 55(a) and (b) schematically show the cross-section of element A when the load sensor 1 is cut along a plane parallel to the X-Z plane at C1-C2 in Figure 54, according to this modified example.

[0423] In this modified example, the flat surface 52a (see Figure 53) of the load distribution plate 50 is fixed to the upper surface 11 of the first base member 10 via an adhesive member 62. In the unloaded state, the load distribution plate 50 and the first base member 10 are separated in the Z-axis direction in areas other than the flat surface 52a (the inclined surface 52b and the flat surface 52c). Also, in the unloaded state, the lower end of the side surface 53 of the load distribution plate 50 (the upper end of the inclined surface 52b) is set to a position lower than the upper surface of the guide 90. This prevents the inclined surface 52b from riding up onto the upper surface of the guide 90, which would prevent the load applied to the load distribution plate 50 from being properly transmitted downwards.

[0424] <Effects of Modification Example 14> As shown in Figures 55(a) and (b), with the side surface 53 of the load distribution plate 50 facing the side surface 91 of the guide 90, the load distribution plate 50 is guided vertically by the guide 80. As a result, similar to Embodiment 7, tilting of the load distribution plate 50 is suppressed even when a load is locally applied to the end of the load distribution plate 50.

[0425] In this modified example as well, as shown in Figure 52, the guide 90 is installed on the upper surface 11 of the first base member 10, making it easy to install the guide 90.

[0426] As shown in Figures 55(a) and (b), since a slope 52b is provided on the lower surface 52 of the load distribution plate 50, the first base member 10 is reliably separated from the load distribution plate 50 in areas other than the pressure-sensitive part A1. This makes it easier for the conductive elastic body 20 to further cover the area around the wire 30, thereby increasing the sensitivity of the pressure-sensitive part A1.

[0427] <Example of modification 18> In Example of modification 14, the guide 90 was installed on the upper surface 11 of the first base member 10, but it is not limited to this, and may be installed integrally with the second base member 70.

[0428] Figure 56 is a schematic diagram showing a cross-section of element A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to this modified example.

[0429] In this modified example, compared to the modified example 14 shown in Figure 55(a), all the guides 90 and the second base member 70 are integrally formed. That is, each guide 90 is formed to protrude in the positive Z-axis direction from the upper surface 71 of the flat-shaped second base member 70 in modified example 14. In this case, the first base member 10 is provided with a hole 13 that penetrates the first base member 10 in the Z-axis direction. The upper end of each guide 90 protrudes from the upper surface 11 of the first base member 10 in the positive Z-axis direction through the hole 13.

[0430] <Effect of Modification Example 18> The guide 90 is integrally installed on the second base member 70.

[0431] With this configuration, the position of the guide 90 can be fixed, allowing the load distribution plate 50 to be guided accurately in the vertical direction.

[0432] The guide 90 is integrally formed with the second base member 70. That is, the guide 90 and the second base member 70 are made of the same material and are molded using the same process during manufacturing.

[0433] This configuration eliminates the need to install the guide 90 on the second base member 70 during manufacturing, and allows for precise positioning of the guide 90 relative to the second base member 70.

[0434] Furthermore, the guide 90 is not limited to being integrally formed with the second base member 70; it may be constructed separately from the second base member 70 and installed on the second base member 70 during manufacturing. In this case, the guide 90 may be made of a different material than the second base member 70.

[0435] <Modification Example 19> In Embodiment 7, the load distribution plate 50 was guided vertically by the inner surface 83a of the opening 83 provided in the guide 80, but the configuration for guiding the load distribution plate 50 is not limited to this. For example, the load distribution plate 50 and the guide 80 may be configured as shown in the plan views of Figures 57(a) to 58(b).

[0436] In the modified examples shown in Figures 57(a) to 58(b), for convenience, a configuration is shown in which one load distribution plate 50 is guided by one guide 80. However, similar to Embodiment 7, one guide 80 may have multiple configurations for guiding multiple load distribution plates 50.

[0437] In the modified example shown in Figure 57(a), semi-cylindrical projections S1 with generatrixes extending in the Z-axis direction are formed on each of the four inner surfaces 83a of the opening 83. In the modified example shown in Figure 57(b), projections S2 are formed on each of the inner surfaces 83a of two opposing corners on the hypotenuse of the substantially rectangular opening 83. Each projection S2 has a shape that combines two rectangular prisms facing each other on two adjacent surfaces 53. The load distribution plate 50 in Figures 57(a) and (b) is configured in the same manner as in Embodiment 7.

[0438] In the modified example shown in Figure 57(a), similar to Embodiment 7, the load distribution plate 50 has a rectangular upper surface 51 and a rectangular lower surface 52, giving it a rectangular shape in plan view, and the guide 80 guides each of the four sides 53 of the load distribution plate 50 in the vertical direction. In the modified example shown in Figure 57(b), the load distribution plate 50 has a rectangular shape in plan view, and the guide 80 guides each of the two opposing corners on the slanted side of the rectangular load distribution plate 50 in the vertical direction. In these configurations as well, the load distribution plate 50 can be smoothly guided in the vertical direction while suppressing the tilt of the load distribution plate 50. Furthermore, compared to Embodiment 7, since the portion of the guide 80 facing the load distribution plate 50 is limited to the protrusions S1 and S2, the load distribution plate 50 can be smoothly moved in the Z-axis direction along the protrusions S1 and S2.

[0439] In Figures 57(a) and (b), the protrusions S1 and S2 are provided on the guide 80, but they may also be provided on the load distribution plate 50 side. Also, in Figure 57(a), the protrusion S1 may be cylindrical with a generatrix extending in the Z-axis direction. In this case, the frame shape of the guide 80 is omitted, and the guide 80 is composed of each protrusion S1. Furthermore, the load distribution plate 50 in Figures 57(a) and (b) may have a polygonal shape other than a rectangle in plan view, and the outer circumference of the load distribution plate 50 in plan view may be composed of straight lines and curves.

[0440] In the modified example shown in Figure 58(a), the load distribution plate 50 is cylindrical in shape with a side surface 53, the opening 83 has a cylindrical side shape with a generatrix extending in the Z-axis direction, and three protrusions S3 are formed on the inner surface 83a of the opening 83, projecting toward the load distribution plate 50. The load distribution plate 50 has a circular upper surface 51, a circular lower surface 52, and a cylindrical side surface 53 connecting the upper surface 51 and the lower surface 52. The three protrusions S3 are arranged at equal intervals in the circumferential direction with respect to the center of the load distribution plate 50. Inside the protrusions S3, a surface S31 is formed that faces the side surface 53 of the load distribution plate 50. The surface S31 has a cylindrical side shape with a generatrix extending in the Z-axis direction.

[0441] In the configuration shown in Figure 58(a), the load distribution plate 50 has a cylindrical shape with a side surface 53, and the guide 80 has a surface S31 facing at least two positions on the side surface 53 of the load distribution plate 50. With this configuration, the two facing surfaces S31 can suppress the tilting of the load distribution plate 50 in the X-axis and Y-axis directions, and the load distribution plate 50 can be smoothly guided in the vertical direction.

[0442] In Figure 58(a), the projection S3 is provided on the guide 80, but it may also be provided on the load distribution plate 50 side. Also, in Figure 58(a), the projections S3 may be arranged independently, or they may be cylindrical in shape with a generatrix extending in the Z-axis direction. In this case, the frame shape of the guide 80 is omitted, and the guide 80 is composed of each projection S3. Also, the load distribution plate 50 in Figure 58(a) may be elliptical in plan view, and the outer circumference of the load distribution plate 50 in plan view may be composed of straight lines and curves. Also, in Figure 58(a), the opening 83 may have a cylindrical side shape to match the shape of the load distribution plate 50, or the opening 83 may be circular in plan view. Also, two or more projections S3 may be arranged at equal intervals in the circumferential direction with respect to the center of the load distribution plate 50.

[0443] In the modified example shown in Figure 58(b), a rectangular prism-shaped hole 54 is formed in the center of the load distribution plate 50 in a plan view. The hole 54 penetrates the load distribution plate 50 in the Z-axis direction. The inner surface of the hole 54 is perpendicular to the X-Y plane. In addition, a rectangular prism-shaped guide 80 is installed inside the hole 54 in a plan view. The inner surface of the hole 54 and the outer surface 85 of the guide 80 face each other. In this case as well, when a load is applied to the upper surface of the load distribution plate 50, the guide 80 guides the load distribution plate 50 in the vertical direction.

[0444] <Modification Example 20> In Embodiment 7, the guide 80 guided the four sides 53 of the load distribution plate 50 in the vertical direction, but the portion of the load distribution plate 50 guided by the guide 80 is not limited to this. For example, as shown in Figure 59, the guide 80 may be positioned to face only the side 53 located at the end of the load distribution plate 50 in the X-axis direction.

[0445] As shown in Figure 59, in this modified example, each load distribution plate 50 is arranged so as to be sandwiched in the X-axis direction by two guides 80. For convenience, only the two guides 80 installed for one load distribution plate 50 are shown in Figure 59. The guides 80 are rectangular prisms, and the inner surface 83a of the guide 80 facing the load distribution plate 50 is parallel to the Y-Z plane. The guides 80 in this modified example are arranged on the upper surface 11 of the first base member 10, similar to Embodiment 7, and more preferably, they are installed on the second base member 70, similar to Modified Example 18.

[0446] The two guides 80 that sandwich the load distribution plate 50 suppress the tilting of the load distribution plate 50 in the X-axis direction, so that even when a load is locally applied to the end of the load distribution plate 50 in the X-axis direction, the load can be properly detected over a relatively high range. On the other hand, although the tilting of the load distribution plate 50 in the X-axis direction is suppressed, the load distribution plate 50 can tilt in the Y-axis direction. Therefore, the detected load when a load is locally applied to the end of the load distribution plate 50 in the Y-axis direction may be smaller than the detected load when the same load is applied to the entire load distribution plate 50.

[0447] However, in this modified example, even if a load is locally applied to the Y-axis end of the load distribution plate 50, since the pressure-sensitive part A1 is provided at the end of the load distribution plate 50 in the Y-axis direction, the load distribution plate 50 is less likely to tilt in the Y-axis direction, and the accuracy of load detection can be maintained to a certain extent. In order to reliably suppress the tilting of the load distribution plate 50, it is preferable that the tilting of the load distribution plate 50 in both the X-axis direction and the Y-axis direction is suppressed, as in Embodiment 7.

[0448] <Modification Example 21> In Embodiment 7, the dielectric 32 was arranged to cover the surface of the conductor wire 31, but the dielectric 32 is not limited to this, and may be arranged between the conductive elastic body 20 and the conductor wire 31. For example, as shown in Figure 60(a), it may be arranged on the lower surface (the negative Z-axis side) of the conductive elastic body 20.

[0449] The dielectric 32 of this modification example is formed on the lower surface of the conductive elastic body 20 as compared with the seventh embodiment shown in FIG. 47(a). Note that the dielectric 32 may be formed on the lower surface 12 of the first base member 10 so as to straddle the lower surfaces of all the conductive elastic bodies 20. Further, as shown in FIG. 60(b), a guide 90 may be disposed on the lower surface 52 of the load dispersion plate 50 instead of the guide 80, and inclined surfaces 52b and flat surfaces 52c may be provided, similar to the fourteenth modification example shown in FIG. 55(a).

[0450] Also in this modification example, even when a load is locally applied to the end of the load dispersion plate 50, the guide 80 or the guide 90 can suppress the inclination of the load dispersion plate 50. Therefore, a locally applied load can be appropriately detected up to a relatively high load range.

[0451] <Modification Example 22> In the seventh embodiment, one element portion A has two pressure-sensitive portions A1. However, as shown in FIG. 61, one element portion A may have one pressure-sensitive portion A1. In this case, in one element portion A, one conductive elastic body 20 and one conductor line 31 intersect. Also in this modification example, the load dispersion plate 50 is guided in the vertical direction, and at least the inclination of the load dispersion plate 50 in the vertical direction is suppressed. Therefore, a locally applied load to the load dispersion plate 50 can be appropriately detected up to a relatively high load range.

[0452] <Embodiment 8> In the seventh embodiment, the pressure-sensitive portion A1 is formed by overlapping the conductive elastic body 20 and the conductor line 31 via the dielectric 32. However, the pressure-sensitive portion A1 may be formed by other configurations. In the eighth embodiment, the pressure-sensitive portion A1 is formed by overlapping an electrode and a protrusion-shaped conductive elastic body via a dielectric.

[0453] FIG. 62 is a diagram schematically showing a cross section of the element portion A when the load sensor 1 is cut along a plane parallel to the X-Z plane according to the eighth embodiment. Hereinafter, configurations different from those of the seventh embodiment will be described.

[0454] In Embodiment 8, the load sensor 1 is provided with one element A. A conductive elastic body 110 is formed on the lower surface 12 of the first base member 10. The conductive elastic body 110 is made of the same material as the conductive elastic body 20 in Embodiment 7. Multiple protrusions 111 are integrally formed on the lower surface of the conductive elastic body 110 in a plan view. The protrusions 111 have a frustoconical shape in which the diameter in the X-Y plane decreases as they extend downward. An electrode 120 is formed on the upper surface 71 of the second base member 70. The electrode 120 is made of a conductive metal (for example, aluminum). A dielectric 130 is formed on the upper surface of the electrode 120. The dielectric 130 is made of the same material as the dielectric 32 in Embodiment 7.

[0455] When a load is applied, the protrusions 111 of the conductive elastic body 110 contract in accordance with the load, increasing the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130. This changes the capacitance between the conductive elastic body 110 and the electrode 120. The potential reflecting this change in capacitance is then measured in the detection circuit, and the load applied to element A is calculated.

[0456] The pressure-sensitive portion A1 is composed of a part of element A in which the contact area between the conductive elastic body 110 and the electrode 120 via the dielectric 130 can change with load. In a plan view, the pressure-sensitive portion A1 is a region with a width W5 centered on the projection 111.

[0457] In Embodiment 8, even when a load is applied locally to the end of the load distribution plate 50, the guide 80 can prevent the load distribution plate 50 from tilting. Therefore, locally applied loads can be properly detected up to a relatively high load range.

[0458] <Embodiment 9> In Embodiment 7, the contact area between the two electrodes (conductive elastic body 20 and conductor wire 31) via the dielectric 32 increased due to the deformation of the first base member 10 and the conductive elastic body 20 by the application of a load. However, the invention is not limited to this, and the contact area between the two electrodes via the dielectric may also increase due to deformation of other parts.

[0459] Figure 63 is a schematic diagram showing a cross-section of the element portion A when the load sensor 1 is cut by a plane parallel to the X-Z plane, according to Embodiment 9. The following describes a configuration that differs from Embodiment 7.

[0460] In Embodiment 9, a second base member 210 is provided in place of the second base member 70. The second base member 210 is made of the same material as the first base member 10. A plurality of conductive elastic bodies 220 are formed on the upper surface 211 of the second base member 210 with gaps in the X-axis direction. The lower surface 212 of the second base member 210 is placed on the installation surface. A plurality of conductive elastic bodies 230 are formed on the lower surface 12 of the first base member 10 with gaps in the Y-axis direction. The conductive elastic bodies 220 and 230 are made of the same material as, for example, the conductive elastic body 20 in Embodiment 7. A layered dielectric 240 is provided between the conductive elastic bodies 220 and 230. The dielectric 240 is made of, for example, a resin material having electrical insulation and elasticity.

[0461] When a load is applied, the first base member 10, the second base member 210, the conductive elastic bodies 220 and 230, and the dielectric 240 deform, increasing the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240. This changes the capacitance between the conductive elastic body 220 and the conductive elastic body 230. The potential reflecting this change in capacitance is measured in the detection circuit, and the load applied to element A is calculated.

[0462] The pressure-sensitive section A1 is composed of a portion of element A in which the contact area between the conductive elastic body 220 and the conductive elastic body 230 via the dielectric 240 can change with load. The width of the pressure-sensitive section A1 in the X-axis direction is W6.

[0463] In Embodiment 9, even when a load is applied locally to the end of the load distribution plate 50, the guide 80 can prevent the load distribution plate 50 from tilting. Therefore, locally applied loads can be properly detected up to a relatively high load range.

[0464] <Other Modification Examples> In embodiments 7 to 9 and modifications 14 to 19 described above, a single-layer load distribution plate 50 is placed on the element A, but two or more layers of load distribution plates 50 may be stacked and arranged. Also, the guides 80 and 90 placed on the upper surface 11 of the first base member 10 may be composed of two or more layers of guides.

[0465] In embodiments 7 to 9 and modified examples 14 to 19 described above, a small gap GP (see Figure 48(a)) was provided between the side surface 53 of the load distribution plate 50 and the inner surface 83a of the guide 80 facing the side surface 53. However, if the friction between the side surface 53 and the inner surface 83a is small, the gap GP may not be provided.

[0466] In embodiments 7 to 9 and modified examples 14 to 19 described above, the entire lower surface 52 of the load distribution plate 50 may be bonded to the upper surface 11 of the first base member 10 by the adhesive member 62. However, as described above, if the adhesive member 62 is placed only near the pressure-sensitive part A1, the first base member 10 in the area where the adhesive member 62 is not placed will bend downward, thereby improving the load detection sensitivity.

[0467] In embodiments 7 to 9 and modified examples 14 to 19, one load distribution plate 50 is arranged in one element section A so as to extend to the area corresponding to the element section A, but two or more load distribution plates 50 may be arranged. In this case, the guide 80 has a frame-shaped opening 83 corresponding to each load distribution plate 50, and each load distribution plate 50 is housed in the corresponding opening 83.

[0468] In the above embodiment 7 and modified examples 14 to 19, three element sections A were arranged in the X-axis direction and the Y-axis direction, respectively. However, the number of element sections A arranged in the X-axis direction and the Y-axis direction may be one, two, or four or more.

[0469] In Embodiment 7 and Modification Examples 14-19 described above, one wire group G1 included one or two wires 30, but it is not limited to this, and one wire group G1 may include three or more wires 30. That is, one element A may have three or more pressure-sensitive parts A1.

[0470] In embodiments 8 and 9 described above, one element A had three pressure-sensitive parts A1, but it may have one, two, or four or more pressure-sensitive parts A1.

[0471] In Embodiment 7 and Modifications 14 to 19 described above, the conductive elastic body 20 was placed only on the lower surface 12 of the first base member 10, but it may also be placed on both the lower surface 12 of the first base member 10 and the upper surface 71 of the second base member 70. In this case, in Modification 21, the dielectric 32 is also placed on the upper surface of the conductive elastic body 20 placed on the upper surface 71 of the second base member 70.

[0472] In Embodiment 7 and Modification Examples 14-19 described above, the cross-sectional shape of the conductor wire 31 was circular, but it is not limited to this, and other shapes such as ellipse or pseudo-circular may also be used.

[0473] In Embodiment 7 and Modifications 14-19 described above, the direction in which the conductive elastic body 20 extends and the direction in which the wire 30 extends are perpendicular to each other. However, the angle between these directions may be an angle other than 90°. That is, the wire 30 may intersect the conductive elastic body 20 at an oblique angle.

[0474] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical idea set forth in the claims.

[0475] (Note) The above description of embodiments discloses the following technologies.

[0476] (Technical 19) A load sensor comprising: a sheet-like first base member having elasticity and having a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; a load distribution plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member; and a guide that guides the load distribution plate in the vertical direction, thereby suppressing the tilt of the load distribution plate in at least the vertical direction, when the direction from the second upper surface to the second lower surface and the direction from the second lower surface to the second upper surface of the load distribution plate are defined as the vertical direction.

[0477] According to this technology, even when a load is locally applied to the edge of the load distribution plate, the load distribution plate is guided in the vertical direction, and tilting of the load distribution plate is suppressed, at least in the vertical direction. As a result, the situation in which the first base member is supported by the second base member due to the tilting of the load distribution plate can be avoided, and detection sensitivity can be maintained at a relatively high load range even when a load is locally applied to the edge of the load distribution plate. Therefore, locally applied loads on the load distribution plate can be properly detected at a relatively high load range.

[0478] (Technical 20) A load sensor according to Technical 19, wherein the guide further suppresses the movement of the load distribution plate in the inward direction of the second upper surface.

[0479] According to this technology, regardless of where a load is applied locally on the load distribution plate, the movement of the second upper surface load distribution plate in the inward direction, i.e., the parallel and rotational movement of the load distribution plate within the second upper surface, is suppressed. As a result, loads can be properly detected up to a relatively high load range, regardless of where a load is applied locally on the load distribution plate.

[0480] (Technology 21) In the load sensor described in Technology 19 or 20, the load distribution plate has a rectangular parallelepiped shape having four side surfaces in addition to the second upper surface and the second lower surface, and the guide guides the four side surfaces of the load distribution plate in the vertical direction respectively. A load sensor characterized by this.

[0481] According to this technology, while suppressing the inclination of the load distribution plate, the load distribution plate can be smoothly guided in the vertical direction.

[0482] (Technology 22) In the load sensor described in Technology 19 or 20, the load distribution plate has a rectangular shape in a plan view in the vertical direction, and the guide guides two opposing corners of the load distribution plate in the vertical direction respectively. A load sensor characterized by this.

[0483] According to this technology, while suppressing the inclination of the load distribution plate, the load distribution plate can be smoothly guided in the vertical direction.

[0484] (Technology 23) In the load sensor described in claim 201 or 202, the load distribution plate has a cylindrical shape having a side surface, and the guide has surfaces facing at least two positions of the side surface of the load distribution plate. A load sensor characterized by this.

[0485] According to this technology, the inclination of the load distribution plate can be suppressed by the surfaces facing two positions, and the load distribution plate can be smoothly guided in the vertical direction.

[0486] (Technology 24) In the load sensor described in any one of Technologies 19 to 23, the guide is installed on the first upper surface of the first base member. A load sensor characterized by this.

[0487] According to this technology, the guide can be easily installed.

[0488] (Technology 25) In the load sensor described in any one of Technologies 19 to 24, the guide is integrally installed on the second base member. A load sensor characterized by this.

[0489] This technology allows the guide's position to be fixed, enabling precise vertical guidance of the load distribution plate.

[0490] (Technical 26) A load sensor according to any one of Technical 19 to 25, characterized in that the guide is integrally formed with the second base member.

[0491] This technology eliminates the need to install guides on the second base member during manufacturing, and allows for precise placement of the guides on the second base member.

[0492] (Technical 27) A load sensor according to any one of Technical 19 to 26, wherein the second base member has a sheet shape with a third upper surface facing the first lower surface of the first base member, the guide has a fourth upper surface which is a planar shape furthest from the first base member in the vertical direction, and when the third upper surface of the second base member is used as the reference for the height in the vertical direction, and the direction from the second base member toward the first base member is the positive height direction, the height of the second upper surface of the load distribution plate when a load of any size is applied is higher than the height of the fourth upper surface of the guide in the unloaded state.

[0493] According to this technology, the second upper surface of the load distribution plate does not move to a position lower than the fourth upper surface of the guide when a load is detected. Therefore, it is possible to avoid a situation where the loaded material comes into contact with the fourth upper surface of the guide, making it impossible to properly detect the applied load.

[0494] (Technical 28) A load sensor according to any one of Technical 19 to 27, wherein an element unit is defined which comprises a first base member, a second base member, and a pressure-sensitive unit, and which detects an applied load based on the capacitance of the pressure-sensitive unit, the load sensor comprises a plurality of element units, each of which is the element unit, and a plurality of load-distributing plates, each of which is the load-distributing plate, the plurality of element units are arranged in a line in the vertical plan view, and each of the plurality of element units is provided with a corresponding load-distributing plate from the plurality of load-distributing plates.

[0495] This configuration allows for a wider load detection surface of the load sensor, and the distribution of the load applied to the load detection surface can be determined by the load detected by each element.

[0496] (Technical 29) A load sensor as described in Technical 28, characterized in that a plurality of the element portions are arranged in a matrix.

[0497] This technology allows for the detection of a two-dimensional (matrix-like) load distribution on the load detection surface of a load sensor.

[0498] (Technical 30) A load sensor according to Technical 28 or 29, wherein the load sensor comprises a plurality of guides, each of which is a guide, and the plurality of guides are integrated in correspondence with a plurality of element portions.

[0499] This configuration eliminates the need to install a guide for each of the multiple element sections, thus simplifying the load sensor's structure.

[0500] (Technical 31) A load sensor according to any one of Technical 19 to 30, wherein the pressure-sensitive part comprises a conductive elastic body formed on the first lower surface of the first base member, a conductor wire arranged opposite to the first lower surface of the first base member and extending in one direction, and a dielectric material arranged between the conductive elastic body and the conductor wire, and the second base member supports the conductor wire.

[0501] This technology allows for a simpler configuration of the pressure-sensitive element.

[0502] (Technical 32) A load sensor according to Technical 31, characterized in that the dielectric is installed so as to cover the surface of the conductor wire.

[0503] According to this technology, a dielectric material can be placed between a conductive elastic material and a conductor wire simply by coating the surface of the conductor wire with a dielectric material.

[0504] 1 Load sensor 10 First base member (base member) 11 Top surface 12 Bottom surface 20 Conductive elastic body 31 Conductor wire 32 Dielectric 50 Load distribution plate 60 Adhesive member A Element part A1 Pressure-sensitive part

Claims

1. A load sensor comprising: 1 or more element units, each of which has one or more pressure-sensitive units whose capacitance changes with load, and which detects load based on the capacitance of the one or more pressure-sensitive units; and 1 or more load-distributing plates, each of which has a corresponding load-distributing plate superimposed on each of the element units, thereby distributing the applied load.

2. A load sensor according to claim 1, wherein one or more pressure-sensitive parts include a plurality of pressure-sensitive parts, and a corresponding load distribution plate is superimposed on each of the element parts in a range that spans the plurality of pressure-sensitive parts.

3. A load sensor according to claim 1, wherein each element portion comprises: a sheet-like base member having elasticity and having an upper surface and a lower surface located opposite the upper surface; a conductive elastic body formed on the lower surface of the base member; one or more conductor wires arranged opposite the conductive elastic body; and a dielectric interposed between the conductive elastic body and each of the one or more conductor wires, wherein each of the one or more pressure-sensitive portions comprises at least a part of the conductive elastic body, at least a part of one corresponding conductor among the one or more conductor wires, and at least a part of the dielectric, and each portion of the element portion is configured such that the contact area between the conductive elastic body and the at least part of one corresponding conductor wire via the dielectric can change with load, and a corresponding load-distributing plate is superimposed on the upper surface of the base member.

4. A load sensor according to claim 3, characterized in that the dielectric is installed so as to cover the surface of one or more of the conductor wires.

5. A load sensor according to claim 1, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions, wherein, in a plan view from the corresponding load distribution plate in the direction in which each of the element portions is located, the adhesive member is positioned within the range of one or more of the pressure-sensitive portions.

6. A load sensor according to claim 3, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions, wherein the contact area changes as the base member and the conductive elastic body deform at each of the pressure-sensitive portions, and in a plan view from the corresponding load distribution plate in the direction in which each of the element portions is located, the adhesive member is positioned within the range of the upper surface of the base member corresponding to the range in which the conductive elastic body can contact the corresponding conductor wire via the dielectric.

7. A load sensor according to claim 4, further comprising an adhesive member for fixing a corresponding load distribution plate and each of the element portions, wherein the contact area changes as the base member and the conductive elastic body deform at each of the pressure-sensitive portions, and in a plan view from the corresponding load distribution plate in the direction in which each of the element portions is located, the range in which the adhesive member is positioned in the direction perpendicular to the extending direction of the corresponding conductor wire includes at least a portion of the range in which the dielectric and the conductive elastic body are in contact when no load is applied, and is within a range of half the length of the circumference whose diameter is the outer diameter of the dielectric covering the corresponding conductor wire.

8. A load sensor comprising: a sheet-like first base member having elasticity and having a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; and a load distribution plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member, wherein when viewed in plan from the first upper surface to the first lower surface of the first base member, the load distribution plate is divided into a first region and second regions on both sides thereof; the pressure-sensitive part is disposed in the first region; the thickness of the load distribution plate in the second regions on both sides is set to be smaller than the thickness of the load distribution plate in the first region, and the second lower surfaces of the load distribution plate in the second regions on both sides are spaced further from the second base member than the second lower surfaces of the load distribution plate in the first region.

9. A load sensor according to claim 8, characterized in that the second lower surface of the load distribution plate in the second region is inclined such that it approaches the second upper surface of the load distribution plate as it moves away from the first region.

10. A load sensor according to claim 8, characterized in that a step is provided on the second lower surface of the load distribution plate in the second region.

11. A load sensor according to claim 8, wherein the pressure-sensitive portion comprises a conductive elastic body formed on the first lower surface of the first base member, a conductor wire positioned opposite the first lower surface of the first base member and extending in one direction, and a dielectric material positioned between the conductive elastic body and the conductor wire, and the second base member supports the conductor wire.

12. A load sensor comprising: a sheet-like first base member having elasticity and having a first upper surface and a first lower surface on the opposite side of the first upper surface; a second base member disposed opposite to the first lower surface of the first base member; a pressure-sensitive part disposed between the first base member and the second base member, the capacitance of which changes with load; a load distribution plate having a second upper surface and a second lower surface on the opposite side of the second upper surface, with at least a part of the second lower surface fixed to the first upper surface of the first base member; and a guide that guides the load distribution plate in the vertical direction, thereby suppressing the tilt of the load distribution plate in at least the vertical direction, when the direction from the second upper surface to the second lower surface and the direction from the second lower surface to the second upper surface of the load distribution plate are defined as the vertical direction.

13. A load sensor according to claim 12, wherein the guide further suppresses the movement of the load distribution plate in the inward direction of the second upper surface.

14. A load sensor according to claim 13, wherein the load distribution plate has a rectangular parallelepiped shape having four sides in addition to the second upper surface and the second lower surface, and the guide guides each of the four sides of the load distribution plate in the vertical direction.

15. A load sensor according to claim 13, wherein the load distribution plate has a rectangular shape in a plan view in the vertical direction, and the guide guides two opposing corners of the load distribution plate in the vertical direction.

16. A load sensor according to claim 13, wherein the load distribution plate has a cylindrical shape with a side surface, and the guide has surfaces facing at least two positions on the side surface of the load distribution plate.

17. A load sensor according to claim 12, characterized in that the guide is installed on the first upper surface of the first base member.

18. A load sensor according to claim 12, characterized in that the guide is integrally installed on the second base member.

19. A load sensor according to claim 18, characterized in that the guide is integrally formed with the second base member.

20. A load sensor according to claim 12, wherein the second base member has a sheet shape with a third upper surface facing the first lower surface of the first base member, the guide has a fourth upper surface which is a planar shape furthest from the first base member in the vertical direction, and when the third upper surface of the second base member is used as the reference height in the vertical direction, and the direction from the second base member toward the first base member is the positive height direction, the height of the second upper surface of the load distribution plate when a load of any size is applied is higher than the height of the fourth upper surface of the guide in the unloaded state.

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