Load detecting device

Abstract

To provide a load detection device capable of suppressing displacement of a linear member.SOLUTION: The load detection device 2 includes a base member 10, a plurality of linear members 30 which are arranged side by side with a gap and in which a plurality of conductive wires are respectively covered with a dielectric, a conductive elastic body formed on an 10a of a facing surface of the base member 10 facing the plurality of linear members 30, a support member 50 having an S1 of an installation surface on which the base member 10 and the plurality of linear members 30 are installed, and a locking portion 200 which is provided on the support member 50 and locks each of the plurality of linear members 30 in a direction in which the plurality of linear members 30 are arranged.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a load detection device that detects an applied load. [Background technology]

[0002] Load sensors have been used in various fields. For example, a load sensor is installed in the finger of a robot arm. This allows the gripping state of the finger that grips an object to be detected from the output of the load sensor.

[0003] For example, Patent Document 1 below describes a capacitance-type load sensor. This load sensor includes an elastic sheet-like base member, a conductive elastic body formed on one side of the base member, and a plurality of conductor wires arranged on top of the conductive elastic body and having their surfaces coated with a dielectric. It also describes that by ensuring that the diameter of the coated linear members and the gaps between the plurality of linear members satisfy predetermined conditions, the range of change in capacitance relative to load can be increased as the number of linear members arranged increases, thereby widening the dynamic range of load detection. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 137837 Summary of the Invention [Problem to be solved by the invention]

[0005] In the load sensor described above, if each linear element is displaced from its normal position in the direction of alignment of the linear elements, causing the gap between the linear elements to fluctuate, the above condition will no longer be satisfied, making it impossible to effectively widen the range of change in capacitance relative to the load, and making it impossible to achieve the desired dynamic range.

[0006] In view of the above problem, an object of the present invention is to provide a load detection device that can suppress positional deviation of a linear member. [Means for solving the problem]

[0007] A main aspect of this aspect relates to a load detection device, which includes a base member, a plurality of linear members arranged side by side with gaps therebetween, each of the conductor wires being coated with a dielectric, a conductive elastic body formed on a surface of the base member facing the linear members, a support member having an installation surface on which the base member and the linear members are installed, and locking portions provided on the support member for locking each of the linear members in the direction in which the linear members are arranged.

[0008] According to the load detection device of this aspect, since each of the linear members is locked in the direction in which the linear members are arranged, the gap between the linear members can be smoothly and stably set to a target distance, which makes it easier for the diameter of the linear members and the gap between the linear members to meet the above conditions, thereby widening the dynamic range of load detection. [Effects of the Invention]

[0009] As described above, according to the present invention, it is possible to provide a load detection device that can suppress positional deviation of a linear member.

[0010] The effects and significance of the present invention will become more apparent from the following description of the embodiments, however, the embodiments shown below are merely examples of how the present invention can be implemented, and the present invention is not limited to the embodiments described below. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an exploded perspective view showing the configuration of a load sensor and a load detection device according to an embodiment. [Figure 2]FIG. 2 is a diagram showing an intersection state between the conductive elastic body and the linear member on the opposing surface of the base member according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the configuration of the load detection device according to the embodiment. [Figure 4] FIG. 4 is a plan view of the entire wiring board according to the embodiment, developed into a flat state. [Figure 5] 5(a) and 5(b) are perspective views showing the configuration of a support member according to the embodiment. [Figure 6] Fig. 6(a) is a perspective view showing a step of sewing a base member to a wiring board according to the embodiment, and Fig. 6(b) is a side view showing the configuration of a load detection device according to the embodiment. [Figure 7] 7(a) and 7(b) are schematic diagrams showing a cross section of a load detection device according to an embodiment, near the intersection of a strip region and a conductive elastic body, when the load detection device is cut at a midpoint in the X-axis direction by a plane parallel to the YZ plane. [Figure 8] Fig. 8(a) is a perspective view showing the configuration of a locking portion according to an embodiment, and Fig. 8(b) is a cross-sectional view schematically showing the periphery of one groove in the C1-C2 cross section according to an embodiment. [Figure 9] 9(a) to 9(d) are cross-sectional views showing the periphery of one groove according to modified examples of the shape of the groove of the locking portion. [Figure 10] 10(a) and 10(b) are side views showing the configuration of the locking portion according to an example of a modified shape of the locking portion. [Figure 11] FIG. 11 is a perspective view showing the configuration of a load detection device according to a modified example of the shape of the installation surface. [Figure 12] Fig. 12(a) is a plan view showing the configuration of a support member according to an example where the position of the locking portion is changed, and Fig. 12(b) is a perspective view showing the configuration of the locking portion according to an example where the position of the locking portion is changed. [Figure 13]Fig. 13(a) is a cross-sectional view showing a schematic view of the vicinity of a position where a locking portion is arranged in the load detection area, according to an example where the position of the locking portion is changed. Fig. 13(b) is a cross-sectional view showing a schematic view of the vicinity of a position where a locking portion is not arranged in the load detection area, according to an example where the position of the locking portion is changed. DETAILED DESCRIPTION OF THE INVENTION

[0012] The load detection device according to the present invention can be applied to systems and equipment that perform processing in response to an applied load. The load sensor in the following embodiments is, for example, a capacitance-type load sensor that is placed on the finger of a robot arm. Such load sensors are also sometimes called "capacitive pressure-sensitive sensor elements," "capacitive pressure detection sensor elements," "pressure-sensitive switch elements," etc. The load sensor is connected to a detection circuit, and the detection circuit detects the load from changes in capacitance. However, the following embodiments are one embodiment of the present invention, and the present invention is not limited to the following embodiments in any way.

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. For convenience, each drawing is labeled with X, Y, and Z axes that are orthogonal to each other. The positive direction of the Z axis is the height direction of the load sensor 1 and the load detection device 2.

[0014] Fig. 1 is an exploded perspective view showing the configuration of a load sensor 1 and a load detection device 2 according to an embodiment. Fig. 2 is a diagram showing the intersection state of a conductive elastic body 20 and a linear member 30 on an opposing surface 10a (surface on the negative side of the Z axis) of a base member 10.

[0015] 1 and 2, the load sensor 1 includes a base member 10, a plurality of conductive elastic bodies 20, a plurality of linear members 30, a fixing member 41, and a wiring board 100. The load detection device 2 includes the load sensor 1, a fixing member 42, and a support member 50.

[0016] The base member 10 is an elastic, flat-plate-like member. The base member 10 has a rectangular shape in a plan view. The thickness of the base member 10 is constant. If the thickness of the base member 10 is small, the base member 10 may be called a sheet member or a film member. The base member 10 is insulating and is made of, for example, a non-conductive resin material or a non-conductive rubber material. The surface of the base member 10 on the negative side of the Z axis is an opposing surface 10a that faces the wiring board 100.

[0017] As shown in FIG. 2, a plurality of conductive elastic bodies 20 are arranged in parallel on the opposing surface 10a of the base member 10. Here, six conductive elastic bodies 20 are arranged side by side in the X-axis direction. Each conductive elastic body 20 has a strip-like shape and is arranged side by side in the X-axis direction with a predetermined gap between them. The long side of each conductive elastic body 20 is parallel to the Y-axis. The six conductive elastic bodies 20 have the same width, length, and thickness. The conductive elastic bodies 20 are elastic, conductive members.

[0018] An electrode pattern 21 is formed on the opposing surface 10a at the position where each conductive elastic body 20 is arranged, and the conductive elastic body 20 is arranged on the opposing surface 10a so as to cover the electrode pattern 21. The six electrode patterns 21 extend to six holes 11 formed at the end of the base member 10 on the negative side of the Y axis. The end of each electrode pattern 21 on the negative side of the Y axis surrounds the periphery of the corresponding hole 11. The ends of these electrode patterns 21 form terminal portions 21a for electrically connecting each conductive elastic body 20 to the wiring board 100.

[0019] The electrode patterns 21 are made of a material with lower resistance than the conductive elastic body 20. The electrode patterns 21 are elastic, conductive members, and the thickness of the electrode patterns 21 is smaller than the thickness of the conductive elastic body 20. The width and thickness of each electrode pattern 21 are the same. The conductive elastic body 20 is arranged so that the electrode patterns 21 are positioned at the middle position in the width direction of the conductive elastic body 20.

[0020] The conductive elastic body 20 and the electrode pattern 21 are made of a resin material with a conductive filler dispersed therein, or a rubber material with a conductive filler dispersed therein. For example, C (carbon) is used as the conductive filler in the conductive elastic body 20, and Ag (silver) is used as the filler in the electrode pattern 21. However, the fillers used in the conductive elastic body 20 and the electrode pattern 21 are not limited to these, and fillers made of other conductive materials may also be used.

[0021] The conductive elastic body 20 and the electrode pattern 21 are formed on the opposing surface 10a by a printing method such as screen printing, gravure printing, flexographic printing, offset printing, gravure offset printing, etc. After the electrode pattern 21 is formed on the opposing surface 10a, the conductive elastic body 20 is formed so as to overlap the electrode pattern 21.

[0022] According to the above printing method, the conductive elastic body 20 and the electrode pattern 21 can be formed to a thickness of about 0.001 mm to 0.5 mm on the opposing surface 10a of the base member 10. However, the method for forming the conductive elastic body 20 and the electrode pattern 21 is not limited to the printing method.

[0023] On the opposing surface 10a, a plurality of linear members 30 are arranged at predetermined intervals in six strip-shaped regions A1 that intersect with the six conductive elastic bodies 20, respectively. The plurality of linear members 30 arranged in one strip-shaped region A1 constitute one group G1 for load detection. For convenience, six linear members 30 are shown in one strip-shaped region A1 in FIG. 2, but as shown in FIG. 1, eight linear members 30 are arranged in one strip-shaped region A1. However, the number of linear members 30 arranged in one strip-shaped region A1 is not limited to this, and it is sufficient that at least two linear members 30 are arranged in one strip-shaped region A1.

[0024] As will be described later, the linear member 30 is composed of a conductor wire 31 and a dielectric 32 that covers the conductor wire 31 (see FIG. 7(a)). The conductor wire 31 is a linear conductive member. The conductor wire 31 is composed of a metal 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 may be composed of a core wire made of resin and a conductive layer formed on its surface. The conductor wire 31 may be a twisted wire made of twisted wires made of a conductive metal material. The dielectric 32 has electrical insulating properties and is composed of, for example, a resin material, a ceramic material, a metal oxide material, or the like.

[0025] Each region where six conductive elastic bodies 20 intersect with six strip-shaped regions A1 constitutes an element unit for load detection. In the example of FIG. 2, 36 element units in 6 columns and 6 rows are arranged in a matrix on the opposing surface 10a. A rectangular region that includes all the element units for load detection becomes the load detection region A2. As shown in FIG. 2, when multiple linear members 30 are arranged in each strip-shaped region A1, multiple linear members 30 are arranged in one element unit, thereby improving the load detection sensitivity of each element unit.

[0026] 1, wiring board 100 is a flexible member in which a plurality of conductive elastic bodies 20 and a plurality of linear members 30 are electrically connected and integrated. Wiring board 100 has six holes 101 at positions corresponding to the six holes 11 of base member 10. Terminal portions 123 are formed around each hole 101. These terminal portions 123 are joined to terminal portions 21a of electrode patterns 21 formed around holes 11 of base member 10.

[0027] Six terminal portions 121, 122 are arranged on the outer surfaces of two flange portions 100a, 100b of the wiring board 100, respectively. Both ends of the linear members 30 of one group G1 are fixed with solder 70 (see FIG. 3) to the terminal portions 121, 122 aligned in the X-axis direction. At both ends of the linear members 30, the dielectric 32 is removed, exposing the conductor wires 31.

[0028] Terminal portion 121 is connected to wiring within wiring board 100, but terminal portion 122 is not connected to wiring within wiring board 100. In other words, the six terminal portions 121 arranged on flange portion 100a on the negative side of the X-axis are used to fix linear members 30 of the corresponding group G1 to wiring board 100 and to connect linear members 30 (conductor wires 31) of the corresponding group G1 to a detection circuit (not shown) via wiring board 100. On the other hand, the six terminal portions 122 arranged on flange portion 100b on the positive side of the X-axis are used only to fix linear members 30 of the corresponding group G1 to wiring board 100.

[0029] The fixing member for fixing both ends of the linear member 30 to the terminal portions 121, 122 is not limited to the solder 70, and may be another fixing member that is conductive and capable of fixing both ends of the linear member 30. Furthermore, since the terminal portion 122 is not connected to the wiring inside the wiring board 100, the fixing member installed on the terminal portion 122 may be a non-conductive material.

[0030] Six openings 102 penetrating the wiring board 100 are formed in each of the two flange portions 100a, 100b of the wiring board 100. The openings 102 on the flange portion 100a side are formed on the positive side of the terminal portion 121 along the Z axis, and the openings 102 on the flange portion 100b side are formed on the positive side of the terminal portion 122 along the Z axis.

[0031] The fixing member 41 is a fixing means for fixing the end of the base member 10 on the Y-axis positive side to the upper surface of the wiring board 100. The fixing member 41 is, for example, a double-sided tape. However, the fixing member 41 is not limited to this, and may be other fixing means such as an adhesive.

[0032] The fixing member 42 is a fixing means for fixing the wiring board 100 to the support member 50. The fixing member 42 has an area large enough to cover the installation surface S1, which is made up of the upper surface and both side surfaces of the first member 51 that constitutes the support member 50. However, the fixing member 42 is provided with a pair of openings 42a that penetrate the fixing member 42 at positions corresponding to the twelve locking portions 200, which will be described later. The fixing member 42 is, for example, double-sided tape. However, the fixing member 42 is not limited to this, and may be other fixing means, such as an adhesive.

[0033] The support member 50 is a base that supports the load sensor 1. The support member 50 is formed by combining a first member 51 and a second member 52. The support member 50 is made of a material that is more rigid than the base member 10. The support member 50 is preferably a rigid body. Here, a rigid body means that the rigidity is high enough to be considered a rigid body in practical use. The support member 50 is made of a metal material such as SUS.

[0034] The first member 51 and the second member 52 have a semi-cylindrical shape that is curved convexly in a direction parallel to the XZ plane. The height of the second member 52 is smaller than the height of the first member 51. The first member 51 and the second member 52 have legs 51a and 52a for installing the support member 50, to which the load sensor 1 is attached, on the finger portion of a robot arm or the like.

[0035] The top surface of the first member 51 and two side surfaces connected to the top surface in a direction parallel to the XZ plane form the installation surface S1 of the load sensor 1 (wiring board 100). The top surface of the first member 51 is curved in a direction along the linear member 30 (a direction parallel to the XZ plane in FIG. 1), and the side surfaces on the X-axis positive side and the X-axis negative side of the first member 51 are parallel to the YZ plane. The wiring board 100 is fixed to the installation surface S1 by a fixing member 42.

[0036] Six locking portions 200 protruding from the surface of the first member 51 are formed near the upper end of the side surface of the first member 51 on the positive side of the X axis, and six locking portions 200 protruding from the surface of the first member 51 are formed near the upper end of the side surface of the first member 51 on the negative side of the X axis. The six locking portions 200 on the positive side of the X axis and the six locking portions 200 on the negative side of the X axis are positioned symmetrically in the X axis direction. As will be described later, each locking portion 200 has a plurality of grooves 210 (see FIG. 8(a)) for locking the plurality of linear members 30 of group G1 in the Y axis direction.

[0037] Like the support member 50, the locking portion 200 is made of a material that is more rigid than the base member 10, and the support member 50 is preferably a rigid body. In this embodiment, the locking portion 200 is made of the same material as the first member 51 and is integrally formed with the first member 51. Note that the locking portion 200 may be made of a different material from the first member 51 and may be separately installed on the first member 51.

[0038] During assembly, with the second member 52 separated from the first member 51, the wiring board 100 is attached to the mounting surface S1 of the first member 51 using the fixing member 42. At this time, the locking portions 200 provided on the first member 51 protrude outward through the openings 42a of the fixing member 42 and the openings 102 of the wiring board 100. Next, with tension applied to the linear members 30 using a jig, the linear members 30 of each group G1 are fitted into the grooves 210 of the corresponding locking portions 200. Then, both ends of the linear members 30 of each group G1 are joined to the corresponding terminal portions 121, 122 with solder 70 (see FIG. 3 ). In this way, the linear members 30 of each group G1 are electrically connected to the wiring board 100 and fixed to the wiring board 100.

[0039] Furthermore, the base member 10 is placed on the wiring board 100 so that the six holes 11 of the base member 10 overlap with the six holes 101 of the wiring board 100. As a result, the terminal portions 21a (see FIG. 2) of the electrode patterns 21 arranged around each hole 11 overlap with the terminal portions 123 arranged around each hole 101.

[0040] In this state, the base member 10 and the wiring board 100 are sewn together with thread 60 (see FIG. 3) through holes 11 and 101 so that overlapping terminal portions 21a and 123 are pressed together. As a result, the end of the base member 10 on the Y-axis negative side is fixed to the wiring board 100, and the six conductive elastic bodies 20 are electrically connected to the wiring board 100. At this time, the load detection area A2 (see FIG. 2) overlaps the curved upper surface of the first member 51.

[0041] Furthermore, the end of the base member 10 on the Y-axis positive side is fixed to the upper surface of the wiring board 100 by the fixing member 41. This fixing of the base member 10 by the fixing member 41 may be performed before the above-mentioned stitching. Thereafter, the second member 52 of the support member 50 is assembled to the first member 51. In this way, the assembly of the load detection device 2 is completed as shown in FIG. 3.

[0042] As shown in FIG. 3, the locking portions 200 are located outside the load detection area A2 (see FIG. 2). A pair of locking portions 200, located on the positive and negative sides of the X-axis of the first member 51, lock the plurality of linear members 30 of one group G1 in a tensioned state. The linear members 30 of each group G1 are fixed to the corresponding terminal portions 121, 122 with solder 70. As a result, each linear member 30 is arranged to extend in a direction parallel to the XZ plane. In addition, the end of the base member 10 on the negative side of the Y-axis is fixed to the wiring board 100 with thread 60 via a hole 101.

[0043] The method of joining the terminal portion 21a (see FIG. 2) of the electrode pattern 21 to the corresponding terminal portion 123 is not limited to sewing with thread 60, but may be other joining methods such as adhesion with a conductive adhesive or crimping with a conductive crimping member.

[0044] FIG. 4 is a plan view of the wiring board 100 unfolded in a flat state.

[0045] A cover layer 110 is formed on the upper surface side (positive side of the Z axis) of the wiring substrate 100. In FIG. 4, terminal portions 121, 122, and 123 and the wiring connected thereto are shown in gray. Six terminal portions 121 arranged on the wiring layer are exposed from six openings 111 formed in a flange portion 110a of the cover layer 110. Six terminal portions 122 arranged on the wiring layer are exposed from six openings 111 formed in a flange portion 110b of the cover layer 110. Furthermore, six terminal portions 123 arranged on the wiring layer are exposed from openings 112 of the cover layer 110.

[0046] The six terminals 121 on the negative side of the X-axis are each connected to one end of a wire arranged on a wiring layer. The six terminals 123 are also each connected to one end of a wire arranged on a wiring layer. These wires extend to the end of the wiring substrate 100 on the negative side of the Y-axis. The six terminals 122 on the positive side of the X-axis are not connected to any wires.

[0047] As described above, both ends of the linear members 30 of the corresponding group G1 are fixed to the terminal portions 121, 122 aligned in the X-axis direction with solder 70. The six openings 102 on the flange portion 100a side are formed on the positive side of the X-axis of the six terminal portions 121, and the six openings 102 on the flange portion 100b side are formed on the negative side of the X-axis of the six terminal portions 122. In addition, six terminal portions 21a (see FIG. 2) arranged on the underside of the base member 10 are joined to the six terminal portions 123 with threads 60 (see FIG. 3).

[0048] 5(a) and 5(b) are perspective views showing the configuration of the support member 50. FIG.

[0049] As shown in FIG. 5( a ), the support member 50 is made up of a first member 51 , a second member 52 , and a screw 53 .

[0050] In addition to the leg portion 51a described above, the first member 51 has a recess 51b, a screw hole 51c, and two protrusions 51d. The recess 51b fits over the protrusion 52b of the second member 52. The screw hole 51c is threadedly engaged with the threaded portion of the screw 53. The two protrusions 51d engage with two recesses (not shown) formed on the upper surface of the protrusion 52b of the second member 52, respectively.

[0051] In addition to the leg portion 52a described above, the second member 52 has a flat protrusion 52b, a circular recess 52c, and a circular hole 52d. The head of the screw 53 fits into the recess 52c. The hole 52d passes through the protrusion 52b from the center of the recess 52c in the vertical direction. The diameter of the hole 52d is slightly larger than the diameter of the threaded portion of the screw 53. The threaded portion of the screw 53 is inserted into the hole 52d.

[0052] The protrusion 52b of the second member 52 is fitted from below into the recess 51b of the first member 51. This aligns the hole 52d of the second member 52 with the screw hole 51c of the first member 51. In this state, the screw 53 is fastened to the screw hole 51c. This integrates the first member 51 and the second member 52, forming the support member 50 shown in FIG. 5(b). As described above, the height H2 of the second member 52 is lower than the height H1 of the first member 51.

[0053] FIG. 6(a) is a perspective view showing a process of sewing the base member 10 to the wiring board 100. FIG.

[0054] As described above, the wiring board 100 is sewn to the base member 10 with the second member 52 detached from the first member 51. As described with reference to FIG. 1, prior to this sewing, the wiring board 100 is attached to the mounting surface S1 of the first member 51 with the fixing member 42, and the linear members 30 are attached to the wiring board 100 with the solder 70 while being locked by the locking portions 200. Furthermore, the base member 10 is placed on the upper surface of the wiring board 100 so that the six holes 11 (see FIG. 1) of the base member 10 are aligned with the six holes 101 of the wiring board 100. Then, as shown in FIG. 6(a), the wiring board 100 and the base member 10 are sewn together with thread 60 through these holes 11, 101. Furthermore, the end of the base member 10 on the Y-axis positive side is fixed to the upper surface of the wiring board 100 with the fixing member 41 (see FIG. 1).

[0055] 5(a) and (b), the second member 52 is assembled to the first member 51 to form the support member 50. At this time, because the height H2 of the second member 52 is lower than the height H1 of the first member 51, a gap is created between the upper surface of the second member 52 and the wiring board 100. As shown in FIG. 6(b), the stop balls 61 on both ends of the string 60 fit into this gap. In this way, the assembly of the load detection device 2 is completed.

[0056] Figures 7(a) and (b) are schematic diagrams showing a cross section of the load detection device 2 near the intersection of the strip region A1 and the conductive elastic body 20 when the load detection device 2 is cut at a midpoint in the X-axis direction by a plane parallel to the YZ plane.

[0057] Note that one group G1 contained in one strip area A1 includes eight linear members 30, but for convenience, six linear members 30 are illustrated as one group G1 in Figures 7(a) and (b).

[0058] Fig. 7(a) shows a state where no load is applied, and Fig. 7(b) shows a state where a load is applied. The linear member 30 is composed of a conductor wire 31 and a dielectric 32. The dielectric 32 covers the outer periphery of the conductor wire 31.

[0059] As shown in FIG. 7(a), when no load is applied to the upper surface of the load detection device 2 (the upper surface of the base member 10), the force acting between the linear member 30 and the conductive elastic body 20 is almost zero. From this state, when a load is applied to the upper surface of the base member 10 as shown in FIG. 7(b), the linear member 30 deforms the conductive elastic body 20. At this time, the linear member 30 is brought closer to the conductive elastic body 20 so as to be wrapped in the conductive elastic body 20, and the contact area between the linear member 30 and the conductive elastic body 20 increases. This causes a change in the capacitance between the conductor wire 31 and the conductive elastic body 20. A voltage reflecting this change in capacitance is measured in the detection circuit.

[0060] In this embodiment, the multiple linear members 30 included in one group G1 are electrically connected in a detection circuit. The detection circuit detects a change in voltage when a constant voltage is applied to the intersection (element portion area) of the strip region A1 and the conductive elastic body 20 based on the capacitance between the multiple conductor wires 31 included in one group G1 and one conductive elastic body 20. The voltage changes depending on the capacitance between the conductor wire 31 and the conductive elastic body 20 in the element portion area. The detection circuit detects the load applied to the element portion from this voltage change. The detection circuit switches the element portion to which the voltage is applied, thereby switching the element portion to be detected. In this way, the detection circuit sequentially detects the load applied to all element portions.

[0061] If the diameter of the linear members 30 is W1 and the gap between the linear members 30 in the band-shaped region A1 is W2, then by increasing the number of linear members 30, the range of change in capacitance relative to load can be increased and the dynamic range of load detection can be widened by satisfying a predetermined condition whereby the diameter W1 and the gap W2 satisfy a predetermined condition. For example, the predetermined condition is that when the diameter W1 is 0.3 mm or less, the gap W2 is 0.6 mm or more, and when the diameter W1 is greater than 0.3 mm, the gap W2 is at least twice the diameter W1.

[0062] However, if each linear component 30 is displaced from its normal position in the arrangement direction (Y-axis direction) of the linear components 30, causing a change in the gap W2 between the linear components 30, the above condition is no longer satisfied. As a result, the range of change in capacitance relative to the load cannot be effectively widened, and the desired dynamic range cannot be achieved.

[0063] Therefore, in this embodiment, as described above, the support member 50 is provided with locking portions 200 that lock each linear member 30 in the arrangement direction (Y-axis direction). This allows the gap W2 between the linear members 30 to be set to a target distance, making it easier for the diameter W1 and gap W2 to meet the above conditions, and widening the dynamic range of load detection. The configuration of the locking portions 200 will be described in more detail below.

[0064] FIG. 8( a ) is a perspective view showing the configuration of the locking portion 200 .

[0065] The locking portion 200 has a protruding shape that protrudes from the surface of the first member 51 of the support member 50. The multiple linear members 30 are locked to the locking portion 200 with a gap in the direction in which the multiple linear members 30 are arranged (the Y-axis direction). The locking portion 200 has multiple grooves 210 into which the multiple linear members 30 included in one group G1 are respectively fitted. The linear members 30 are fitted into the grooves 210 through the openings 102 of the wiring substrate 100. As a result, each linear member 30 is locked in the direction in which the linear members 30 are arranged (the Y-axis direction), so that the linear members 30 can be smoothly installed at the target gap W2 during the installation work of the linear members 30, and even after the installation work of the linear members 30, the linear members 30 are less likely to become misaligned, making it easier to maintain the target gap W2.

[0066] Moreover, each groove 210 extends in a direction along the linear members 30. By having the grooves 210 extend along the linear members 30, it is possible to prevent unnecessary force from being applied from the grooves 210 to the linear members 30 that are arranged extending in a direction parallel to the XZ plane, and therefore damage to the linear members 30 can be avoided.

[0067] FIG. 8(b) is a cross-sectional view schematically showing the periphery of one groove 210 in the C1-C2 cross section of FIG. 8(a).

[0068] The groove 210 has a bottom surface 211 on which the linear members 30 are placed, and a pair of side surfaces 212 facing the linear members 30 in the arrangement direction (Y-axis direction) of the linear members 30. In Fig. 8(b), the bottom surface 211 and the pair of side surfaces 212 are both flat surfaces, and the pair of side surfaces 212 are parallel to the XZ plane.

[0069] 8(b), since the pair of side surfaces 212 are parallel to the XZ plane, in order for the linear member 30 to fit into the groove 210, the distance W3 between the pair of side surfaces 212 needs to be set slightly larger than the diameter W1 of the linear member 30. As a result, a gap Gp is ​​generated between the linear member 30 and the side surfaces 212. Therefore, although the linear member 30 moves slightly in the Y-axis direction depending on the width of the gap Gp, the movement of the linear member 30 in the Y-axis direction can be suppressed compared to when the locking portion 200 is not arranged.

[0070] <Effects of the embodiment> According to the embodiment, the following effects are achieved.

[0071] As shown in Figures 1 and 2, the load detection device 2 comprises a base member 10, a plurality of linear members 30 arranged side by side with gaps therebetween, each having a plurality of conductor wires 31 coated with a dielectric 32, a conductive elastic body 20 formed on the opposing surface 10a of the base member 10 facing the plurality of linear members 30, a support member 50 having an installation surface S1 on which the base member 10 and the plurality of linear members 30 are installed, and a locking portion 200 provided on the support member 50 for locking each of the plurality of linear members 30 in the direction in which the plurality of linear members 30 are arranged (the Y-axis direction).

[0072] According to this configuration, each of the linear members 30 is locked in the direction in which the linear members 30 are arranged, so that the gap W2 (see FIG. 7(b)) between the linear members 30 can be smoothly and stably set to a target distance. This makes it easier for the diameter W1 (see FIG. 7(b)) of the linear members 30 and the gap W2 between the linear members 30 to meet the above-mentioned conditions, and the dynamic range of load detection can be expanded.

[0073] As shown in FIGS. 2 and 3, the locking portion 200 is provided outside the load detection area A2 where the plurality of linear members 30 and the conductive elastic body 20 overlap.

[0074] According to this configuration, the locking portion 200 can be arranged in the load detection area A2 while preventing the locking portion 200 from interfering with load detection.

[0075] As shown in FIG. 8(a), the locking portion 200 has a plurality of grooves 210 into which the plurality of linear members 30 are fitted, respectively.

[0076] According to this configuration, it is possible to suppress movement of the linear members 30 in two mutually opposing directions parallel to the direction in which the linear members 30 are arranged (the Y-axis direction).

[0077] As shown in FIG. 1, the installation surface S1 is curved in the direction along the linear member 30.

[0078] Even if the installation surface S1 is curved in this way, it is possible to prevent the plurality of linear members 30 from being misaligned in the arrangement direction (Y-axis direction).

[0079] As shown in FIG. 3, the load detection device 2 further includes solder 70 (fixing member) that fixes the ends of the plurality of linear members 30 to the support member 50.

[0080] According to this configuration, the linear members 30 can be maintained in a state in which they are locked by the locking portions 200 in the arrangement direction.

[0081] 3 and 4, the load detection device 2 includes a wiring board 100 fixed to a support member 50. Solder 70 (fixing member) is conductive and fixes the ends of the plurality of linear members 30 to corresponding terminal portions 121, 122 of the wiring board 100. The plurality of linear members 30 are locked to locking portions 200 that protrude through openings 102 formed in the wiring board 100.

[0082] According to this configuration, the plurality of linear members 30 can be connected to an external circuit via the wiring board 100. Furthermore, the plurality of linear members 30 can be locked to the locking portion 200 without being hindered by the wiring board 100. Furthermore, for example, by providing a shielding layer on the wiring board 100, the influence of external noise on the detection signal can be suppressed by the shielding layer.

[0083] <Example of changing the shape of the groove in the locking part> The shape of the groove 210 of the locking portion 200 is not limited to the configuration shown in the above embodiment, and various modifications are possible.

[0084] 9(a) to 9(c), the pair of side surfaces 212 may be inclined surfaces that approach the middle position in the width direction (Y-axis direction) of the groove 210 as they approach the bottom surface 211. In this case, the angle formed between the pair of side surfaces 212 and the bottom surface 211 is an obtuse angle.

[0085] In the example shown in Figure 9(a), the linear member 30 is placed on the bottom surface 211, and a gap Gp is ​​provided between the linear member 30 and a pair of side surfaces 212, while in the example shown in Figure 9(b), the linear member 30 is placed on the bottom surface 211 and is in contact with the pair of side surfaces 212, and in the example shown in Figure 9(c), the linear member 30 is supported only by the pair of side surfaces 212.

[0086] 9(b) and (c), when the linear members 30 are fitted into the grooves 210, the linear members 30 receive force from the slopes (side surfaces 212) in the arrangement direction of the linear members 30 (Y-axis direction) and are pressed against the inner surfaces of the grooves 210. This allows the linear members 30 to be reliably positioned in the arrangement direction of the linear members 30. Furthermore, according to the example shown in FIGS. 9(a) to (c), the mold can be smoothly removed from the grooves 210 when molding the grooves 210, and the linear members 30 can be smoothly fitted into the grooves 210 when assembling the load detection device 2.

[0087] 9(d), the cross section of the groove 210 may be arc-shaped. In this case, the groove 210 has a side surface shape of an elliptical cylinder, and the length of the cross section of the groove 210 in the Y-axis direction is slightly larger than the diameter of the linear member 30. As a result, when the linear member 30 is fitted into the groove 210, the linear member 30 is guided to the lowest point of the arc shape. Therefore, the linear member 30 can be stably and reliably positioned in the arrangement direction of the linear member 30 (Y-axis direction). Also in this case, the mold can be smoothly removed from the groove 210 when molding the groove 210, and the linear member 30 can be smoothly fitted into the groove 210 when assembling the load detection device 2.

[0088] 9(a) to 9(c), both of the pair of side surfaces 212 are inclined, but either one of the pair of side surfaces 212 may be parallel to the XZ plane, similar to the side surface 212 in FIG. 8(b). Also, one or both of the pair of side surfaces 212 may be curved. Also, in the configuration of FIG. 8(b), the pair of side surfaces 212 may be inclined or curved from the middle of the groove 210 in the depth direction.

[0089] <Example of change in the shape of the locking part> The shape of the locking portion 200 is not limited to the configuration shown in the above embodiment, and various modifications are possible.

[0090] For example, as shown in FIG. 10( a), the locking portion 200 may be configured with a plurality of protrusions 220 protruding from the surface of the first member 51. The shape of the protrusions 220 is, for example, cylindrical. In this modified example, the linear member 30 in the load detection region A2 also extends along the YZ plane. However, in this modified example, the ends of the linear member 30 abut against the side surfaces of a corresponding pair of protrusions 220 and are bent in the same direction, and both ends of the linear member 30 are installed on the wiring board 100. Therefore, each linear member 30 is pressed against the side surface of the corresponding protrusion 220 at its bending point. As a result, similar to the above embodiment, the linear members 30 are locked in the arrangement direction (Y-axis direction), and the gap between the linear members 30 in the load detection region A2 is fixed to a predetermined size.

[0091] 10(b), compared to the above embodiment, a pair of locking portions 200 aligned in the X-axis direction may be arranged rotated in the same direction. In this case, the width of the groove 210 may be set wider than in the above embodiment. In this configuration, the linear member 30 is bent at the upper end of the side surface 212 on the Y-axis positive side of the groove 210, and the linear member 30 is pressed against the upper end of the side surface 212 at this bending point. In this case, as in FIG. 10(a), the linear members 30 are locked in the alignment direction (Y-axis direction), and the gap between the linear members 30 in the load detection area A2 is fixed to a predetermined size.

[0092] <Example of changing the shape of the installation surface> FIG. 11 is a perspective view showing the configuration of the load detection device 2 according to a modified example of the shape of the installation surface S1.

[0093] The load detection device 2 of this modified example differs from the above embodiment in the configuration of the support member 50. In the above embodiment, the installation surface S1 of the support member 50 is curved in the direction in which the linear member 30 extends (a direction parallel to the XZ plane), but in this modified example, the installation surface S1 of the support member 50 is curved in a direction perpendicular to the direction in which the linear member 30 extends (a direction parallel to the YZ plane).

[0094] The support member 50 has a semi-cylindrical shape that is convexly curved in a direction parallel to the YZ plane. As in the above embodiment, the support member 50 has legs 50a for installing the support member 50, to which the load sensor 1 is attached, on a finger portion of a robot arm or the like. In a plan view, the support member 50 has a shape that is symmetrical in the X-axis direction and in the Y-axis direction. Unlike the above embodiment, the support member 50 is composed of only one member.

[0095] The top surface of the support member 50 and two side surfaces connected to the top surface in a direction parallel to the XZ plane form the installation surface S1 of the load sensor 1 and the wiring board 100. The top surface of the support member 50 is curved in a direction perpendicular to the direction along the linear member 30 (a direction parallel to the YZ plane), and the side surfaces on the X-axis positive side and the X-axis negative side of the support member 50 are parallel to the YZ plane. Locking portions 200 similar to those in the above embodiment are provided near the upper ends of the side surfaces on the X-axis positive side and the X-axis negative side of the support member 50.

[0096] Wiring board 100 is placed on mounting surface S1 using a fixing member (such as double-sided tape) with a contour similar to that of mounting surface S1. In order to fit wiring board 100 along the X-axis positive side surface of support member 50, the end of wiring board 100 on the X-axis positive side is divided into two flange portions 100c. Although not shown in FIG. 11 , the end of wiring board 100 on the X-axis negative side is also similarly divided into two flange portions 100c. When unfolded in a planar state, the shape of wiring board 100 is symmetrical in the X-axis direction.

[0097] The wiring board 100 has a plurality of openings 102 formed therethrough in ranges corresponding to the vicinity of the upper ends of the sides of the support member 50 on the positive and negative sides of the X-axis. As in the above embodiment, the linear members 30 of each group G1 are locked to the corresponding locking portions 200 via the openings 102. In the configuration of FIG. 11, one opening 102 is formed for one flange portion 100c, and the linear members 30 of three groups G1 are locked to the three locking portions 200 via one opening 102. The shape of the locking portions 200 can be modified in the same manner as in the above modified example.

[0098] On the four flanges 100c, terminals 121, 122 (terminal 121 is not shown in FIG. 11) are arranged at the positions of the ends of the linear members 30 of the corresponding group G1. The ends of the linear members 30 of each group G1 are fixed to the corresponding terminals 121, 122 with solder 70. As in the above embodiment, the terminal 121 arranged on the flange 100c on the negative side of the X-axis is connected to wiring within the wiring board 100.

[0099] The configurations of the base member 10, the six conductive elastic bodies 20 formed on the lower surface thereof, and the electrode pattern 21 are the same as those in the above embodiment. The base member 10 is placed on the upper surface of the wiring board 100 so that the six conductive elastic bodies 20 intersect with the six groups G1 of linear members 30. The terminal portion 21a on the base member 10 side and the terminal portion 123 on the wiring board 100 side are joined with, for example, a conductive adhesive. The end of the base member 10 on the positive side of the Y axis is fixed to the upper surface of the wiring board 100 with a fixing member 41.

[0100] In this modified example, the installation surface S1 is curved in the arrangement direction of the multiple linear members 30. Even when the installation surface S1 is curved in this way, it is possible to suppress positional deviation in the arrangement direction (Y-axis direction) of the multiple linear members 30.

[0101] <Example of changing the position of the locking part> In the above embodiment, the locking portion 200 is provided outside the load detection area A2, but is not limited to this and may be provided inside the load detection area A2.

[0102] FIG. 12(a) is a plan view showing the configuration of a support member 50 according to this modified example.

[0103] In this modified example, compared to the above embodiment shown in Fig. 5(b), twelve locking portions 200 are provided on the installation surface S1 rather than on the X-axis positive and X-axis negative side surfaces of the support member 50. The configuration of the locking portions 200 in this modified example is the same as in the above embodiment. In Fig. 12(a), the base member 10 and conductive elastic body 20 shown in Fig. 2 are shown by dashed lines in a planar state and a transparent state for convenience.

[0104] In this modified example, all of the locking portions 200 are provided inside the load detection area A2 and overlap the conductive elastic body 20 in the Z-axis direction after assembly. Furthermore, the openings 102 provided in the wiring board 100 are formed at positions where the 12 locking portions 200 shown in FIG. 12(a) protrude in the positive direction of the Z-axis. In this modified example, assembly is performed in the same manner as in FIG. 1. At this time, as shown in FIG. 12(b), each linear member 30 is fitted into a corresponding groove 210 through the opening 102 of the wiring board 100. Each groove 210 extends in a direction along the linear member 30.

[0105] Fig. 13(a) is a cross-sectional view showing the vicinity of a position where the locking portion 200 is arranged in the load detection area A2 according to this modified example. Fig. 13(b) is a cross-sectional view showing the vicinity of a position where the locking portion 200 is not arranged in the load detection area A2 according to this modified example. For convenience, six linear members 30 are shown as one group G1 in Figs. 13(a) and (b).

[0106] As shown in FIG. 13(a), the groove 210 in this modified example has an arc shape. In the height direction, the lower end of the groove 210 coincides with the upper surface of the wiring substrate 100. Also, as shown in FIG. 13(b), the lower ends of the linear members 30 at positions where there are no locking portions 200 are grounded to the upper surface of the wiring substrate 100. Therefore, the positions of the linear members 30 in the height direction are equal within the load detection region A2, and therefore the contact area between the conductive elastic body 20 and the linear members 30 can be made approximately the same regardless of the position where the load is applied in the load detection region A2. This makes it possible to suppress unintended variations in the load detected for each element unit.

[0107] 13(a), the height of the groove 210 (the length in the direction perpendicular to the upper surface of the locking portion 200) is H3, which is smaller than the radius (W1 / 2) of the linear member 30. As a result, when a load is applied from the no-load state of FIG. 13(a), the conductive elastic body 20 comes into contact with the upper surface of the locking portion 200, which prevents the increase in the electrostatic capacitance between the conductive elastic body 20 and the conductor wire 31 from being hindered.

[0108] In this modified example, the locking portion 200 is provided inside the load detection area A2 where the plurality of linear members 30 and the conductive elastic body 20 overlap. With this configuration, an area for providing the locking portion 200 outside the load detection area A2 is not required, and therefore the load detection device 2 can be made smaller.

[0109] In this modification, the locking portion 200 is arranged so as to overlap the conductive elastic body 20 inside the load detection area A2, but is not limited to this, and the locking portion 200 may be arranged so as not to overlap the conductive elastic body 20 inside the load detection area A2. In other words, the locking portion 200 may be arranged between a plurality of conductive elastic bodies 20.

[0110] <Other change examples> In the above embodiment, the upper surface of the support member 50 (the curved portion of the installation surface S1) is curved in the direction in which the linear members 30 extend, and in the modified example shown in Fig. 11, the upper surface of the support member 50 is curved in a direction perpendicular to the direction in which the linear members 30 extend. However, the upper surface of the support member 50 is not limited to this, and may be curved in a spherical shape, for example.

[0111] In the above embodiment, the installation surface S1 is curved in a direction along the linear members 30, but in the modified example shown in FIG. 11, the installation surface S1 is curved in the direction in which the multiple linear members 30 are arranged. However, the shape of the installation surface S1 is not limited to this and may be, for example, flat. In this case, for example, the upper surface of the support member 50 is configured to be flat, and the installation surface S1 is provided on the upper surface of the support member 50. Even when the installation surface S1 is flat, each linear member 30 is locked by the locking portion 200 in the direction in which the linear members 30 are arranged.

[0112] In the above embodiment, six groups G1 are provided as shown in Fig. 2, but the present invention is not limited to this and may provide, for example, one group G1. Also, in the above embodiment, six conductive elastic bodies 20 are provided as shown in Fig. 2, but the present invention is not limited to this and may provide, for example, one conductive elastic body 20.

[0113] In the above embodiment, the wiring board 100 is configured to cover the upper surface of the support member 50, but is not limited thereto, and may be configured to cover only a portion of the side surface of the support member 50 without covering the upper surface of the support member 50. Also, the wiring board 100 may be omitted. In this case, terminal portions and wiring connected to the detection circuit are provided on the support member 50, and the linear members 30 are fixed to the terminal portions provided on the support member 50 with solder 70.

[0114] In the above embodiment, the load was detected by a capacitance-type load detection structure including a conductive elastic body 20 and a linear member 30, but the load detection method is not limited to this, and the load may also be detected by, for example, a resistance-type load detection structure.

[0115] In addition, the embodiments of the present invention can be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims.

[0116] <Additional Notes> The above description of the embodiments discloses the following techniques.

[0117] (Technology 1) A base member; a plurality of linear members arranged side by side with gaps therebetween, each of which is a plurality of conductor wires covered with a dielectric; a conductive elastic body formed on a surface of the base member facing the plurality of linear members; a support member having an installation surface on which the base member and the plurality of linear members are installed; a locking portion provided on the support member and configured to lock each of the plurality of linear members in a direction in which the plurality of linear members are arranged, A load detection device characterized by:

[0118] According to this technology, each of the linear members is locked in the direction in which they are aligned, so that the gap between the linear members can be smoothly and stably set to a target distance. This makes it easier for the diameter of the linear members and the gap between the linear members to meet the above conditions, thereby widening the dynamic range of load detection.

[0119] (Technology 2) In the load detection device described in Technical 1, the locking portion is provided outside a load detection area where the plurality of linear members and the conductive elastic body overlap. A load detection device characterized by:

[0120] According to this technique, the locking portion can be arranged in the load detection area while preventing the locking portion from interfering with load detection.

[0121] (Technology 3) In the load detection device according to Technology 1 or 2, The locking portion has a plurality of grooves into which the plurality of linear members are fitted, respectively. A load detection device characterized by:

[0122] According to this technique, it is possible to suppress the movement of the linear members in two mutually opposing directions parallel to the direction in which the linear members are arranged.

[0123] (Technology 4) In the load detection device described in Technical 3, The groove has one or two slopes that approach a middle position in the width direction of the groove as it approaches the bottom surface. A load detection device characterized by:

[0124] According to this technology, when a linear member is fitted into a groove, the linear member receives a force from the slope in the direction of alignment of the linear member and is pressed against the inner surface of the groove, thereby reliably positioning the linear member in the direction of alignment of the linear member. In addition, the mold can be smoothly removed from the groove when molding the groove, and the linear member can be smoothly fitted into the groove when assembling the load detection device.

[0125] (Technology 5) In the load detection device according to Technology 3 or 4, The cross section of the groove is arc-shaped. A load detection device characterized by:

[0126] According to this technique, when the linear members are fitted into the grooves, the linear members are guided to the lowest point of the arc shape, thereby enabling the linear members to be stably and reliably positioned in the direction of arrangement of the linear members.

[0127] (Technology 6) In the load detection device according to any one of techniques 3 to 5, The groove has a bottom surface on which the linear members are placed and a pair of side surfaces facing the linear members in the arrangement direction. A load detection device characterized by:

[0128] (Technology 7) In the load detection device according to any one of techniques 1 to 6, The installation surface is curved in a direction along the linear members or in the arrangement direction. A load detection device characterized by:

[0129] Even if the installation surface is curved in this way, it is possible to prevent the position of the multiple linear members from shifting in the arrangement direction.

[0130] (Technology 8) In the load detection device according to any one of techniques 1 to 7, Further provided is a fixing member that fixes the ends of the plurality of linear members to the support member. A load detection device characterized by:

[0131] According to this technique, the linear members can be maintained in a state in which they are locked by the locking portions in the arrangement direction.

[0132] (Technology 9) In the load detection device described in Technical 8, a wiring board fixed to the support member; the fixing member is conductive and fixes the ends of the plurality of linear members to corresponding terminal portions of the wiring board; The plurality of linear members are engaged with the engaging portions protruding through openings formed in the wiring substrate. A load detection device characterized by:

[0133] This technology allows a plurality of linear members to be connected to an external circuit via a wiring board, and also allows the plurality of linear members to be locked in the locking portions without being obstructed by the wiring board. [Explanation of symbols]

[0134] 2. Load detection device 10 Base member 10a Opposite surface 20 Conductive elastic body 30 Linear members 31 Conductor wire 32 Dielectric 50 Support member 70 Solder (fixing material) 100 wiring board 102 Aperture 121, 122 Terminal section 200 Locking part 210 Groove 211 bottom 212 Side (Slope) A2 Load detection area S1 Installation surface

Claims

1. A base member; a plurality of linear members arranged side by side with gaps therebetween, each of which is a plurality of conductor wires covered with a dielectric; a conductive elastic body formed on a surface of the base member facing the plurality of linear members; a support member having an installation surface on which the base member and the plurality of linear members are installed; a locking portion provided on the support member and configured to lock each of the plurality of linear members in a direction in which the plurality of linear members are arranged, A load detection device characterized by:

2. The load detection device according to claim 1, the locking portion is provided outside a load detection area where the plurality of linear members and the conductive elastic body overlap. A load detection device characterized by:

3. The load detection device according to claim 1, The locking portion has a plurality of grooves into which the plurality of linear members are fitted, respectively. A load detection device characterized by:

4. The load detection device according to claim 3, The groove has one or two slopes that approach a middle position in the width direction of the groove as they approach the bottom surface. A load detection device characterized by:

5. The load detection device according to claim 3, The cross section of the groove is arc-shaped. A load detection device characterized by:

6. The load detection device according to claim 3, The groove has a bottom surface on which the linear members are placed and a pair of side surfaces facing the linear members in the arrangement direction. A load detection device characterized by:

7. The load detection device according to claim 1, The installation surface is curved in a direction along the linear members or in the arrangement direction. A load detection device characterized by:

8. The load detection device according to claim 1, Further provided is a fixing member that fixes the ends of the plurality of linear members to the support member. A load detection device characterized by:

9. The load detection device according to claim 8, a wiring board fixed to the support member; the fixing member is conductive and fixes the ends of the plurality of linear members to corresponding terminal portions of the wiring board; The plurality of linear members are engaged with the engaging portions protruding through openings formed in the wiring substrate. A load detection device characterized by:

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