Pressure sensor and pressure sensor unit

Abstract

To provide a pressure sensor having excellent load resistance regardless of simple structure, and to provide a pressure sensor unit having the pressure sensor.SOLUTION: A pressure sensor 1 includes a nearly cylindrical elastic core 2 having a pressure reception surface 2a in one end side and a sheet-like sensor member 3 disposed on a side face of the elastic core 2, and detects pressure by deformation of the sensor member 3 following application of a load to the pressure reception surface 2a, the sensor member 3 is made of elastomer, and has two sets of conductive layers and at least a layer of insulation layer interposed between the conductive layers, and one conductive layer, the insulation layer, and the other conductive layer are disposed in order from the inside on a side face of the elastic core 2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a pressure sensor and a pressure sensor unit including the pressure sensor.

Background Art

[0002] Conventionally, as a pressure sensor, a pressure sensor that detects a change in capacitance accompanying a load is known. In this pressure sensor, by detecting a change in capacitance with a plurality of detection units, the pressure distribution in the plane direction of the pressure sensor can be measured. Such a pressure sensor is installed, for example, on a bed or the like, and is used for measuring the body pressure distribution of a person sleeping in the bed.

[0003] As a capacitance type pressure sensor, a sensor having a structure in which electrodes form a matrix in a sheet shape is known. For example, in Patent Document 1, a sheet-like pressure sensor having an elastomer dielectric layer, a front electrode portion disposed on the front side of the dielectric layer and formed including an elastomer and a conductive filler, and a back electrode portion disposed on the back side of the dielectric layer and formed including an elastomer and a conductive filler is described. The front electrode portion has a plurality of front electrodes formed in a strip shape, and each electrode extends in the X-axis direction. Further, the back electrode portion has a plurality of back electrodes formed in a strip shape, and each electrode extends in the Y-axis direction. In this pressure sensor, in addition to the dielectric layer, the front electrode portion and the back electrode portion are formed of an elastomer. Therefore, when a load is applied to the detection unit, the front electrode and the back electrode extend together with the dielectric layer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the case of a pressure sensor in which electrodes are combined in a sheet shape, as described in Patent Document 1 above, the entire sheet receives the load, making the sheet prone to damage and raising concerns regarding load-bearing capacity. Furthermore, it becomes necessary to consider the structure of the support for the sheet, which may lead to increased structural complexity.

[0006] This invention was made to address these circumstances, and aims to provide a pressure sensor with a simple structure that is excellent in load-bearing capacity, and a pressure sensor unit equipped with said pressure sensor. [Means for solving the problem]

[0007] The pressure sensor of the present invention comprises a substantially columnar elastic core material having a pressure-receiving surface at one end, and a sheet-like sensor member disposed on the side surface of the elastic core material, and is characterized in that it detects pressure by the deformation of the sensor member due to a load being applied to the pressure-receiving surface.

[0008] The sensor member described above is made of elastomer and has two sets of conductive layers and at least one insulating layer interposed between these conductive layers, characterized in that one conductive layer, the insulating layer, and the other conductive layer are arranged on the side surface of the elastic core material in order from the inside out.

[0009] The elastic core material is characterized in that the width of the insulating layer in the axial direction is greater than the width of the other conductive layer.

[0010] The insulating layer has a thickness of 20 μm to 150 μm, and the conductive layer has a thickness of 50 μm to 200 μm.

[0011] The sensor member is arranged so as to substantially circle the side surface of the elastic core material and is fixed to the elastic core material at one point in the circumferential direction.

[0012] The present invention is characterized by having a resin film placed between the elastic core material and the sensor member.

[0013] The pressure sensor unit of the present invention is characterized in that a plurality of pressure sensors of the present invention are arranged on a substantially flat surface. [Effects of the Invention]

[0014] The pressure sensor of the present invention comprises a substantially columnar elastic core material having a pressure-receiving surface at one end, and a sheet-like sensor member arranged on the side of the elastic core material. Since it detects pressure by the deformation of the sensor member due to a load being applied to the pressure-receiving surface, the elastic core material can receive external loads, resulting in a pressure sensor with excellent load-bearing capacity despite its simple structure.

[0015] The sensor component comprises two sets of conductive layers and at least one insulating layer interposed between these conductive layers. Specifically, it consists of a first laminate formed by laminating an insulating layer and a conductive layer, and a second laminate formed by laminating an insulating layer and a conductive layer. At least one of the insulating layers from the first laminate and the second laminate is provided between the conductive layer of the first laminate and the conductive layer of the second laminate. With this sensor structure, a change in capacitance occurs in response to the deformation of the sensor component when a load is applied to the pressure-receiving surface, and pressure can be detected based on this capacitance. Furthermore, since the sensor component is made of elastomer, it is easily deformable, resulting in a large change in capacitance and improved sensor accuracy.

[0016] In this design, one conductive layer, an insulating layer, and the other conductive layer are arranged on the side of the elastic core material from the inside out. Since the width of the insulating layer in the axial direction of the elastic core material is greater than the width of the conductive layer located outside the insulating layer, even if the sensor member deforms, the conductive layer located inside the insulating layer and the conductive layer located outside the insulating layer are less likely to come into contact. This effectively prevents short circuits caused by contact between the two sets of conductive layers.

[0017] The sensor element is positioned to substantially circle the side of the elastic core material and is fixed to the elastic core material at one point in the circumferential direction. Since it is not fixed to the elastic core material at any other point, the sensor element can be easily deformed, thereby improving sensor accuracy.

[0018] Since a resin film is disposed between the elastic core material and the sensor member, the movement of the sensor member is likely to be smooth and it is more likely to be deformed.

[0019] In the pressure sensor unit of the present invention, since a plurality of pressure sensors of the present invention are arranged on a substantially flat surface, it has excellent load resistance and can accurately measure the pressure distribution of an object.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic configuration diagram showing one form of the pressure sensor of the present invention. [Figure 2] It is a schematic plan view of the sensor main body portion of FIG. 1. [Figure 3] It is a diagram for explaining the detection principle of the pressure sensor of the present invention. [Figure 4] It is a diagram for explaining one form of the sensor member. [Figure 5] It is a partial cross-sectional view showing one form of the sensor main body portion provided with the sensor member of FIG. 4. [Figure 6] It is a cross-sectional view showing another form of the sensor main body portion. [Figure 7] It is a schematic configuration diagram showing one form of the pressure sensor unit of the present invention.

Embodiments for Carrying Out the Invention

[0021] One form of the pressure sensor of the present invention will be described based on FIG. 1. FIG. 1 is a schematic configuration diagram of the pressure sensor. The pressure sensor shown in FIG. 1 has a sensor main body portion and a detection portion connected to the sensor main body portion, and is a sensor that detects the pressure when a load is applied to the pressure receiving surface of the sensor main body portion. The pressure sensor of the present invention can be used, for example, as an impact sensor that detects an impact or a vibration sensor that is provided at the lower part of a pipe or the like and detects vibration.

[0022] In Figure 1, the sensor body of the pressure sensor 1 is formed in a substantially cylindrical shape and has as its main components a substantially cylindrical elastic core material 2 and a sheet-like sensor member 3 arranged on the side surface 2b of the elastic core material 2. The sensor member 3 is preferably made of elastomer. The sensor member 3 is arranged on the side surface 2b of the elastic core material 2 either directly or via another material such as a resin film.

[0023] In the pressure sensor 1, the elastic core material 2 has a pressure-receiving surface 2a on one axial side, and is structured to receive external loads on this pressure-receiving surface 2a. The structure of the pressure-receiving surface 2a is not limited to a plane, but can be appropriately set according to the application of the pressure sensor. For example, the pressure-receiving surface 2a may be formed as a curved surface that bulges or is concave in the axial direction.

[0024] The material of the elastic core material 2 is not particularly limited as long as it is flexible and elastic, but it is preferable that it has enough hardness to not deform when the sensor member 3 is wrapped around its side. Specifically, as the elastic core material, foamed elastic materials such as foamed rubber or foamed resin having multiple air bubbles, or solid rubber can be used. In particular, it is preferable to use foamed urethane (urethane sponge) which has excellent cushioning properties (shock absorption capacity).

[0025] In Figure 1, the sensor member 3 is formed in a strip shape and is arranged to substantially encircle the side surface 2b of the elastic core material 2. Specifically, the sensor member 3 encircles the side surface 2b of the elastic core material 2 to a degree that does not complete a full circle (for example, 0.90 turns or more but less than 1.0 turn), and the pair of ends 3a and 3a' are spaced apart from each other. For example, the sensor member 3 is wrapped around the side surface 2b of the elastic core material 2 while tension is applied. A fixing member 6 is provided to cover the pair of ends 3a and 3a' from the outside. The fixing member 6 can be anything that fixes the sensor member 3 to the elastic core material 2, and for example, adhesive tape can be used.

[0026] As shown in Figure 2, the fixing member 6 is bonded to the elastic core material 2 so as to fill the gap between the pair of ends 3a and 3a', thereby fixing the sensor member 3 to the elastic core material 2. In this case, the sensor member 3 is fixed to the elastic core material 2 at one point in its circumferential direction. On the other hand, at other points (most points in the circumferential direction), the sensor member 3 is not fixed to the elastic core material 2 and is in a non-adherent state. In the case of a configuration in which a resin film, described later, is placed in between, the sensor member 3 is in a non-adherent state to the resin film. By fixing the sensor member 3 to the elastic core material 2 at one point in the circumferential direction in this way, separation of the fixing member 6 and the sensor member 3 is avoided, the independence of the sensor member 3 is increased, and it becomes more easily deformable.

[0027] In Figure 1, the sensor member 3 has two sets of conductive layers (not shown) and at least one insulating layer (not shown) interposed between these conductive layers. In this case, one conductive layer, at least one insulating layer, and the other conductive layer are arranged on the side surface of the elastic core material in order from the inside. In this specification, the direction in which these layers are stacked is called the stacking direction. Electrode 7a is attached to the outer conductive layer, and electrode 7b is attached to the inner conductive layer. Electrodes 7a and 7b are connected to the detector 8 via a conductor. For electrodes 7a and 7b, metal foil made of metal such as copper or aluminum, film electrodes such as PET film coated with a metal paste such as copper or aluminum, conductive tape, etc., can be used.

[0028] In Figure 1, the conductive layers of the electrodes and sensor components are exposed in the sensor body, but these may be covered with an insulating film (not shown).

[0029] The pressure sensor 1 in Figure 1 is a capacitive pressure sensor. The detection principle of this pressure sensor will be explained based on Figure 3(a). Figure 3(a) shows a partial cross-sectional view of the pressure sensor. As shown in Figure 3(a), the pressure sensor 1 has two sets of conductive layers 3a and 3b and an insulating layer 3c as the sensor member 3. For convenience, in Figure 3(a), the sensor member 3 is described as having a three-layer structure. When a load F is applied to the pressure-receiving surface 2a of the pressure sensor 1, the elastic core material 2 deforms, and the sensor member 3 also deforms (stretches) accordingly. Then, the distance between the conductive layers 3a and 3b changes according to the deformation of the sensor member 3, and the capacitance changes. Then, by detecting the change in capacitance with a detector, the degree of the load can be determined. In this way, the pressure sensor of the present invention detects pressure by the deformation of the sensor member in response to the applied load.

[0030] Figure 3(b) shows a state in which a load is applied to a conventional sheet-like pressure sensor 21. As shown in Figure 3(b), when a load F is applied to the pressure-receiving surface 22a of the sheet-like sensor member 22, the capacitance changes in accordance with the deformation (extension) of the sensor member 22, and the pressure is detected based on this change in capacitance. In the conventional configuration, the external load is received across the entire surface of the sensor member 22, and the direction in which the load is applied and the direction of extension of the sensor member 22 are approximately the same. Since the load is applied directly to the sensor member, there was a risk of the sensor member becoming worn or damaged.

[0031] In contrast, the pressure sensor 1 according to the present invention has excellent load-bearing capacity because it receives external loads with an elastic core material 2. Furthermore, in the pressure sensor 1, the sensor members 3 are arranged so that the stacking direction of the sensor members 3 is substantially perpendicular to the direction in which the load is applied. In this case, since the sensor members 3 extend in a direction different from the direction in which the load is applied, it is thought that the load on the sensor members 3 can be reduced compared to conventional configurations.

[0032] Next, a specific form of the sensor component will be explained using Figure 4. Figure 4(a) is a side view of the sensor component when it is unfolded in the circumferential direction, and Figure 4(b) is a view from above.

[0033] The sensor member 3 shown in Figure 4 is constructed by overlapping two strip-shaped laminates. When the sensor member 3 is wrapped around an elastic core, the inner laminate 4 is located on the inside (towards the elastic core), and the outer laminate 5 is located on the outside. As shown in Figure 4(a), the central axis in the short direction (width direction) of the inner laminate 4 and the central axis in the short direction (width direction) of the outer laminate 5 are aligned when they are overlapped. In the sensor member 3 shown in Figure 4, the two sets of laminates are identical in all other aspects except for the width (longitudinal length, material of each layer, and thickness of each layer).

[0034] As shown in Figure 4(b), the inner laminate 4 has a two-layer structure consisting of an insulating layer 4a and a conductive layer 4b. The insulating layer 4a and the conductive layer 4b are bonded together. The outer laminate 5 also has a two-layer structure consisting of an insulating layer 5a and a conductive layer 5b. The insulating layer 5a and the conductive layer 5b are bonded together. Both the inner laminate 4 and the outer laminate 5 are made of elastomer and are stretchable. An electrode 7b is attached to the conductive layer 4b, and an electrode 7a is attached to the conductive layer 5b.

[0035] In the configuration shown in Figure 4, the insulating layer 4a of the inner laminate 4 and the insulating layer 5a of the outer laminate 5 are interposed between the conductive layer 4b of the inner laminate 4 and the conductive layer 5b of the outer laminate 5. In other words, the inner laminate 4 and the outer laminate 5 are arranged so that their respective insulating layers 4a and 5a face each other. In this case, the inner laminate 4 and the outer laminate 5 may or may not be bonded to each other. From the viewpoint of suppressing a decrease in the stretchability of each laminate, it is preferable that the inner laminate 4 and the outer laminate 5 are not bonded to each other as much as possible. For example, they may be bonded together at only one point in the circumferential direction using double-sided tape or adhesive.

[0036] In the sensor member 3 shown in Figure 4, the orientation of the outer laminate 5 relative to the inner laminate 4 may be reversed. That is, the insulating layer 4a of the inner laminate 4 and the conductive layer 5b of the outer laminate 5 may be arranged to face each other. Furthermore, even if each laminate deforms, the conductive layer 4b of the inner laminate 4 and the conductive layer 5b of the outer laminate 5 become less likely to come into contact, so it is preferable to arrange the insulating layer 4a and insulating layer 5a to face each other as shown in Figure 4. This effectively prevents short circuits.

[0037] Furthermore, in the sensor component 3, the width of each laminate is made different from the viewpoint of preventing short circuits. Figure 5 shows a partial cross-sectional view of one form of the sensor body equipped with the sensor component of Figure 4. As shown in Figure 5, the width W of the inner laminate 4 in the axial direction of the elastic core material 2 i (The widths of the insulating layer 4a and the conductive layer 4b are the same) is the width W of the outer laminate 5. o (The widths of the insulating layer 5a and the conductive layer 5b are the same.) In this case, the upper and lower ends of the insulating layer 4a are positioned to protrude from the outer laminate 5 in the axial direction of the sensor member 3. By making the width of at least one insulating layer (insulating layer 4a in Figure 5) interposed between the two sets of conductive layers larger than the width of the conductive layer located outside the insulating layer (conductive layer 5b in Figure 5), even if the sensor member is greatly deformed, the two sets of conductive layers are less likely to come into contact, and short circuits can be effectively prevented.

[0038] Here, the capacitance of the sensor component is calculated using the following formula (1). Capacitance C = (S / D) × ε ···(1)

[0039] In equation (1), ε is the dielectric constant, S is the surface area of ​​the detection area, and D is the distance between the pair of conductive layers. The detection area is the area where the pair of conductive layers overlap in the stacking direction. From equation (1), the larger the dielectric constant ε, the larger the capacitance C. Also, the larger the surface area S, the larger the capacitance C, and the smaller the distance D between the pair of conductive layers, the larger the capacitance C. As the capacitance C increases, the change in capacitance with pressure also increases, thus improving the measurement accuracy of the pressure sensor.

[0040] The distance D between a pair of conductive layers corresponds to the thickness of the insulating layer interposed between the pair of conductive layers. Therefore, in order to increase the capacitance C, it is preferable to reduce the thickness of the insulating layer interposed between the conductive layers. Thickness T of insulating layer 4a a The thickness of the insulating layer 4a is, for example, 20 μm to 150 μm, preferably 20 μm to 100 μm. a and the thickness T of the conductive layer 4b b The relationship between these two is not particularly limited, and as shown in Figure 5, the thickness T of the conductive layer 4b b The thickness T of the insulating layer 4a a It may be made larger than this. Thickness T of conductive layer 4b b The thickness is, for example, 50 μm to 200 μm, preferably 50 μm to 150 μm. The numerical range of the thickness of each layer can be appropriately adopted, for example, in the conductive layer and insulating layer of a three-layer sensor member.

[0041] Furthermore, in Figure 5, a resin film 9 is placed between the elastic core material 2 and the sensor member 3. This makes the movement of the sensor member 3 smoother and more easily deformable. Preferably, the resin film 9 is bonded to the elastic core material 2. As the resin film, for example, a PE film can be used.

[0042] The configuration of the pressure sensor of the present invention is not limited to the configurations shown in Figures 1 to 5. For example, although the elastic core material 2 is shown as substantially cylindrical in Figure 1, it is not limited to this and may be substantially elliptical or polygonal. Furthermore, the pressure sensor is not limited to a capacitive pressure sensor; any configuration capable of detecting pressure by deformation of the sensor member due to a load being applied to the pressure-receiving surface is acceptable.

[0043] Furthermore, as shown in Figure 6(a), the elastic core material 2A may have a recessed shape (for example, a bobbin shape) such that a part of its outer surface is reduced in diameter. In this case, the sensor member 3A may be placed in the recessed part of the outer surface. In addition, since the elastic core material is subjected to load, it is preferable that it be solid, but a hollow portion may be provided inside or elsewhere to the extent that it does not impair the effects of the present invention. For example, as shown in Figure 6(b), the elastic core material 2B may have a hollow portion that penetrates in the axial direction.

[0044] The insulating layer and conductive layer in the sensor component will be described below.

[0045] The insulating layer is preferably formed of an elastomer, in which case a rubber composition based on rubber components such as silicone rubber, ethylene-propylene-diene copolymer (EPDM), acrylonitrile butadiene rubber (NBR), natural rubber, butadiene rubber, styrene butadiene rubber, isoprene rubber, butyl rubber, nitrile rubber, chloroprene rubber, fluororubber, or urethane rubber can be used. The above rubber components may be used individually or in mixtures of two or more.

[0046] Among the rubber components mentioned above, silicone rubber is preferred because it exhibits excellent elongation.

[0047] The conductive layer consists of a rubber composition in which a conductive filler is blended with a rubber component, and the conductive properties are due to the dispersion of the conductive filler within the layer. Examples of rubber components used in the conductive layer include silicone rubber, EPDM, NBR, natural rubber, butadiene rubber, styrene-butadiene rubber, isoprene rubber, butyl rubber, nitrile rubber, chloroprene rubber, fluororubber, and urethane rubber. These rubber components may be used individually or in mixtures of two or more. It is preferable that the insulating layer and the conductive layer each have the same type of base rubber component.

[0048] Conductive fillers include solid carbon materials such as graphite powder, conductive carbon black, carbon nanotubes, and fullerenes, as well as metal powders such as copper powder, silver powder, and iron powder, and conductive metal oxides such as conductive tin oxide and conductive titanium oxide. These conductive fillers may be used individually or in combination of two or more. Among these, solid carbon materials are preferred, and graphite powder, conductive carbon black, and carbon nanotubes are more preferred.

[0049] The amount of conductive filler to be blended (total amount if two or more types are used) is preferably 20 to 70 parts by mass, and more preferably 20 to 50 parts by mass, per 100 parts by mass of rubber component.

[0050] As a specific composition for the conductive layer, for example, a rubber composition can be used which consists of 70 parts by mass of conductive silicone rubber, 30 parts by mass of silicone rubber, and 5 parts by mass of carbon nanotube masterbatch.

[0051] The rubber components used in the insulating and conductive layers are preferably crosslinked. Crosslinking methods include radiation crosslinking and chemical crosslinking such as press vulcanization. For press vulcanization, organic peroxides such as 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane can be used as vulcanizing agents.

[0052] For radiation crosslinking, electron beams, gamma rays, X-rays, etc., can be used. In this invention, electron beam irradiation is preferred from the viewpoint of being easy to control the effect of the radiation shielding layer. Electron beam irradiation may be performed from either side of the sensor member, and the number of irradiations, whether single-sided or double-sided, can be adjusted as appropriate depending on the thickness and material composition. The electron beam irradiation conditions are an acceleration voltage of 50kV to 1000kV, preferably 200kV to 500kV, and an irradiation dose (total irradiation dose in the case of multiple irradiations) of 50kGy to 400kGy, preferably 50kGy to 200kGy.

[0053] Other additives may be incorporated into the insulating and conductive layers, provided they do not impair the effects of the invention. For example, vulcanizing agents, vulcanization accelerators, reinforcing agents, anti-aging agents, softeners, colorants, etc., can be incorporated.

[0054] The following describes an example of manufacturing a sensor body having a sensor component consisting of two laminated layers.

[0055] An insulating layer coating is obtained by dissolving the rubber composition constituting the insulating layer in a solvent, filtering it, and degassing it. Any solvent capable of dissolving the rubber component can be used, such as toluene. The obtained coating is applied in strips to a coating film (for example, a 50 μm thick PET film). Any coating method that can form a film can be used, such as the comma bar method, spray method, dipping method, or brush application method. After coating, the insulating layer coating is dried. Drying is carried out, for example, in a constant temperature bath at 90°C for about 10 minutes.

[0056] A conductive layer coating is obtained by dissolving the rubber composition constituting the conductive layer in a solvent, filtering it, and degassing it. The same solvent as that used for the insulating layer coating can be used. The obtained conductive layer coating is applied to a coating film and dried under the same conditions as for the insulating layer coating.

[0057] The drying insulating layer and conductive layer are overlapped and bonded together. Bonding is performed using a pressure roll or the like. After bonding, electron beam irradiation is performed under the irradiation conditions described above to crosslink each layer and bond the insulating layer and conductive layer. Electron beam irradiation may be performed from either the insulating layer side or the conductive layer side, and the number of irradiations and whether it is single-sided or double-sided irradiation are adjusted as appropriate depending on the film thickness. By crosslinking and bonding each layer, an inner laminate and an outer laminate are obtained, respectively.

[0058] The inner and outer laminates are stacked, their insulating layers overlapping each other, to form a sensor component. If necessary, the inner and outer laminates may be bonded together at one point in the circumferential direction using double-sided tape or the like. Then, conductive tape, acting as electrodes, is attached to each conductive layer of the sensor component. Finally, the sensor component is wrapped around the side of a roughly columnar elastic core material, applying tension (for example, an elongation rate (%) (={(length after elongation - length before elongation) / length before elongation} × 100) of 20-40). Afterward, fixing members are attached to cover the pair of ends of the sensor component to obtain the sensor body. Note that a resin film may be interposed when wrapping the sensor component around the elastic core material, if necessary.

[0059] The manufacturing of the sensor body is not limited to the methods described above. For example, instead of molding by coating, each rubber composition may be formed into strips by die molding, extrusion molding, or split molding, in which case press vulcanization is suitable. Molding by coating is preferable in that it allows for longer thin films and good thickness accuracy. Alternatively, a method can be employed in which the conductive layer paint is directly applied to the dried insulating layer paint and dried to bond the layers together.

[0060] Figure 7 shows one embodiment of the pressure sensor unit of the present invention. As shown in Figure 7, the pressure sensor unit 11 is composed of multiple pressure sensors 1 arranged on a substantially flat surface. Specifically, the pressure sensors 1 are fixed to the base 12 on the side opposite to the pressure-receiving surface. With this configuration, the pressure sensor unit 11 can measure the pressure distribution of an object with a complex shape by detecting the capacitance of multiple pressure sensors 1. Therefore, it can be used as a seating sensor or surface sensor to measure body pressure or sitting pressure. Furthermore, since the pressure sensors 1 that constitute each detection part of the pressure sensor unit have excellent load-bearing capacity, the pressure sensor unit becomes one with excellent long-term durability. [Industrial applicability]

[0061] The pressure sensor of the present invention has a simple structure while exhibiting excellent load-bearing capacity, making it suitable for a variety of applications as a pressure sensor. [Explanation of symbols]

[0062] 1. Pressure sensor 2, 2A, 2B Elastic core material 2a Pressure-receiving surface 3, 3A, 3B Sensor components 4. Inner laminate 4a Insulating layer 4b conductive layer 5 Outer laminate 5a Insulating layer 5b Conductive layer 6 Fixing members 7a, 7b electrode 8 detectors 9. Resin film 11. Pressure sensor unit 12 base

Claims

1. It comprises a substantially columnar elastic core material having a pressure-receiving surface at one end, and a sheet-like elastomer sensor member arranged on the side of the elastic core material. The sensor member has two sets of conductive layers and at least one insulating layer interposed between these conductive layers, and on the side surface of the elastic core material, one conductive layer, the insulating layer, and the other conductive layer are arranged in order from the inside. The width of the insulating layer in the axial direction of the elastic core material is greater than the width of the other conductive layer. The sensor member is arranged to substantially circle the side surface of the elastic core material and is fixed to the elastic core material at one point in the circumferential direction. A pressure sensor characterized by detecting pressure based on a change in capacitance caused by the deformation of the sensor member due to a load being applied to the pressure-receiving surface.

2. The pressure sensor according to claim 1, characterized in that the thickness of the insulating layer is 20 μm to 150 μm, and the thickness of the conductive layer is 50 μm to 200 μm.

3. The pressure sensor according to claim 1 or 2, characterized in that a resin film is disposed between the elastic core material and the sensor member.

4. A pressure sensor unit characterized in that a plurality of pressure sensors according to any one of claims 1 to 3 are arranged on a substantially flat surface.

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