WO2017065283A1 - Load sensor, load detecting device and seat for sitting - Google Patents

Abstract

Provided is a load sensor provided with: (1) an electrically conductive resilient member which has a first surface onto which a load is input, and a second surface opposing the first surface, and in which an electrical resistance between the first surface and the second surface varies as a result of resilient compression in accordance with the input load; (2) a first electrode provided in such a way as to oppose the first surface; and (3) a second electrode which is provided in such a way as to oppose the second surface and is electrically connected to the first electrode via the electrically conductive resilient member.

Description

Load sensor, load detection device and seat for seating

The present disclosure relates to a load sensor, a load detection device, and a seat for seating.

The vehicle is provided with a vehicle seat as a seat for seating. In the vehicle seat, a cushion material such as urethane foam is used for the cushion pad of the seat cushion and the seat back, and the seat is elastically deformed by a load received from the seated occupant so that the occupant can have a comfortable sitting comfort.

On the other hand, the vehicle is provided with an occupant protection device such as an air bag device or a seat belt device, and the occupant seated on the vehicle seat is protected by the occupant protection device in the event of a vehicle emergency. Further, the vehicle may be provided with a sensor that detects whether or not an occupant is seated on the vehicle seat. Vehicles with occupant detection sensors on the vehicle seat control the operation of the occupant protection device in the event of a vehicle emergency depending on, for example, whether the occupant is seated on the vehicle seat supported by the occupant protection device is doing.

As an occupant detection sensor provided in a vehicle seat, an electrostatic capacity method, a method using a strain sensor provided between a vehicle seat and a rail for fixing the vehicle seat to a vehicle body, a seat on which an occupant sits A method using a pressure sensor provided in a cushion has been proposed. For example, in Japanese Patent Laid-Open No. 2012-032342, a detection electrode in which conductors are arranged in a comb shape is provided on the surface of a seat cushion pad, and the capacitance between the detection electrode and the vehicle body caused by a passenger sitting on the seat Has proposed a capacitive-type occupant detection sensor that detects a change in the frequency as an oscillation frequency change by an oscillation circuit.

When providing an occupant detection sensor on a vehicle seat, it is required that the seat comfort of the occupant seated on the seat cushion is not affected. Here, as an elastic member such as urethane foam, there is a conductive elastic member whose electric resistance value is changed by being elastically compressed. By using a conductive elastic member for the cushion pad and detecting a change in the electric resistance value of the conductive elastic member, it is possible to detect whether or not an occupant is seated on the seat cushion. It is also possible to detect from the resistance value of the conductive elastic member whether the occupant seated on the vehicle seat is an adult with a large physique (heavy weight) or a child with a small physique (small weight).

By the way, the occupant detection sensor provided on the vehicle seat is required to accurately detect the occupant seated on the seat with a simple configuration without affecting the seating comfort of the occupant. Moreover, it is preferable that the occupant detection sensor provided on the vehicle seat can detect the physique of the seated occupant (for example, whether it is an adult or a dwarf).

Furthermore, in a vehicle equipped with an occupant protection device, when detecting that the occupant is seated on the seat cushion, it is possible to detect not only whether the occupant seated on the seat cushion is an adult or a child, but also a more detailed physique Required.

This disclosure provides a load sensor and a load detection device capable of detecting a load with a simple configuration. The present disclosure also provides a seat for seating that can accurately detect a person's seating and that can detect the physique of the seated person.

The first aspect of the present disclosure includes (1) a first surface to which a load is input and a second surface opposite to the first surface, and is elastically compressed according to the input load. A conductive elastic member that changes an electrical resistance value between the first surface and the second surface; (2) a first electrode provided to face the first surface; and (3) the first surface. And a second electrode that is provided to face two surfaces and is electrically connected to the first electrode via the conductive elastic member.

In the load sensor according to the first aspect, each of the pair of electrodes is opposed to each other with a conductive elastic member having a characteristic that the resistance value decreases by being elastically deformed and compressed according to the load. . The shape of the conductive elastic member may be a cubic shape, a rectangular parallelepiped shape, or a cylindrical shape, and is not limited to these, and has an arbitrary planar shape and a predetermined height, and is elastic by a load. Various shapes whose height changes by being deformed can be applied. In addition, as the pair of electrodes, for example, a sheet-like electrode having a shape matching the planar shape of the conductive elastic member is applied.

According to a second aspect of the present disclosure, in the first aspect described above, at least one of the conductive elastic member, the first electrode, and the second electrode as a mesh in which a plurality of openings having a predetermined size are arranged. An insulating sheet provided between the first electrode and the second electrode through a part of the conductive elastic member that is elastically compressed and enters each of the plurality of openings. Is a load sensor that can be electrically connected to each other.

In the second aspect, the insulating sheet has a mesh shape in which openings of a predetermined size are arranged. The insulating sheet is provided between at least one of the first electrode and the second electrode and the conductive elastic member. For this reason, for example, when the insulating sheet is disposed between the first electrode and the conductive elastic member, the first electrode is removed from the conductive elastic member when no load is input to the conductive elastic member. Since it leaves | separates, the electrical resistance value between a 1st electrode and a 2nd electrode becomes high. Further, when a load is input to the conductive elastic member, a part of the conductive elastic member enters the opening of the insulating sheet. Therefore, each of the first electrode and the second electrode is in contact with the conductive elastic member. Moreover, when the input load increases, the contact area between the conductive elastic member that has entered the opening and the first electrode increases.

Thereby, the first electrode and the second electrode are electrically connected via the conductive elastic member, and the electric resistance value generated in the conductive elastic member and the contact area between the conductive elastic member and the first electrode are increased. A corresponding electrical resistance value is detected. At this time, the electrical resistance value is lowered by compressing the conductive elastic member, and the electrical resistance value is lowered by increasing the contact area between the conductive elastic member and the first electrode. Therefore, the electrical resistance value between the first electrode and the second electrode changes greatly between the state in which no load is input to the conductive elastic member and the state in which the load is input, and the load is applied to the conductive elastic member. Whether it is input or not can be detected with high accuracy. In addition, since the change in the electrical resistance value between the first electrode and the second electrode with respect to the change in the input load is greater than when no insulating sheet is provided, the input load is highly accurate. Can be detected.

According to a third aspect of the present disclosure, in the second aspect, the insulating sheet is provided with a plurality of small holes having an opening smaller than the opening around each of the plurality of openings. It is a load sensor in which the first electrode and the second electrode can be electrically connected through a part of the conductive elastic member that enters each of the plurality of small holes by being elastically compressed.

In the load sensor of the third aspect, a plurality of small holes that are smaller than the opening are formed in the insulating sheet. When the input load increases, the conductive elastic member enters the small hole of the insulating sheet. For this reason, the conductive elastic member and the first electrode (or the second electrode) are connected via the opening and the small hole opened smaller than the opening by further increasing the load input to the conductive elastic member. Therefore, the contact area of the first electrode (or the second electrode) that contacts the conductive elastic member increases. As a result, the electrical resistance value between the first electrode and the second electrode decreases according to the displacement of the conductive elastic member and the increase in the contact area of the first electrode (or the second electrode). It changes more greatly than the electrical resistance value corresponding only to the displacement of the member.

Therefore, since the change of the electrical resistance value between the first electrode and the second electrode is added to the displacement of the electrical resistance value of the conductive elastic member according to the input load, the first electrode and the second electrode The range in which the load input to the conductive elastic member can be detected with high accuracy from the electric resistance value between them is widened.

According to a fourth aspect of the present disclosure, in the first to third aspects described above, the fourth aspect further includes a stretchable sheet disposed to face the first surface of the conductive elastic member, and the first electrode includes: It is a load sensor formed by sewing a conductive thread into the stretchable sheet.

In the fourth aspect, the stretchable sheet is provided so as to face one surface of the conductive elastic member, and the first electrode is provided by being sewn into the stretchable sheet. By providing the first electrode on the stretchable sheet, the first electrode expands and contracts following the elastic deformation of one surface of the conductive elastic member, and can be electrically connected to the conductive elastic member.

In the fourth aspect, conductive yarn is used. The conductive yarn has conductivity, and the first electrode is formed by sewing the conductive yarn into the stretchable sheet. Since the conductive yarn is intermittently held on the stretchable sheet at the seam, it is possible to prevent the stretchability of the stretchable sheet from being impaired.

A fifth aspect of the present disclosure includes a load including the load sensor according to the first to fourth aspects, and a detection unit that detects an electrical resistance value between the first electrode and the second electrode. It is a detection device.

In the load detection device of the fifth aspect, each of the pair of electrodes is connected to the detection means, and the resistance value between the pair of electrodes is detected by the detection means. Thereby, when the resistance value of the conductive elastic member is detected by the detecting means and the conductive elastic member is elastically deformed by receiving a load, the resistance value corresponding to the load that elastically deforms the conductive elastic body. Is obtained.

A sixth aspect of the present disclosure is the load detection device according to the fifth aspect, in which the detection unit determines the load from the electric resistance value.

The load detection device according to the sixth aspect determines the load that is elastically deforming the conductive elastic member from the resistance value between the pair of electrodes. The load may be determined by determining the load value corresponding to the resistance value, and when the load is divided into a plurality of levels according to the magnitude, the load that elastically deforms the conductive elastic member However, it may be determined which level is supported.

A seventh aspect of the present disclosure is a seat for seating provided with the load sensors according to the first to fourth aspects, wherein the conductive elastic member is provided on a cushion pad of the seat cushion, and the first aspect is provided. The seat is a seat for which a surface is an upper surface of the cushion pad and the second surface is a lower surface of the cushion pad.

According to the seventh aspect, the conductive elastic member is provided on the cushion pad. The conductive elastic member provided on the cushion pad is preferably formed with a thickness corresponding to the thickness of the cushion pad, may form part of the cushion pad, and the cushion pad may be formed of the conductive elastic member. It may be formed so that the conductive elastic portion becomes a cushion pad.

In the seat for seating according to the seventh aspect, the conductive elastic member of the seating sensor is provided on the cushion pad of the seat cushion. The region where the conductive elastic member is provided only needs to include a region that receives a load from the seated person, so that when the person sits on the seat cushion, the load according to the physique (weight) of the seated person is conducted. The conductive elastic member is elastically deformed by being input to the conductive elastic member.

Since a load corresponding to the elastic deformation of the conductive elastic member is input between the first electrode and the second electrode, a person can enter the seat cushion from the electric resistance value between the first electrode and the second electrode. Whether the person is seated or the physique of the person who is seated can be detected.

Here, when the seating sheet has the stretchable sheet according to the fourth aspect, the stretchable sheet provided with the first electrode is disposed on the upper surface side of the conductive elastic member, and the conductive elastic member It is expanded and contracted according to the deformation of the upper surface. Thereby, the 1st electrode provided in the elastic sheet does not impair the sitting comfort of the person seated on the seat cushion. Further, from the electrical resistance value between the first electrode and the second electrode, the physique (weight) of the occupant seated on the seat cushion can be detected with high accuracy as the load input to the conductive elastic member.

According to an eighth aspect of the present disclosure, in the seventh aspect, the first electrode and the second electrode are connected to a detection unit that detects an electrical resistance value between the first electrode and the second electrode. This is a seat for seating.

According to the eighth aspect, since the detection means detects the resistance value between the first electrode and the second electrode, the load that elastically deforms the conductive elastic member from the resistance value detected by the detection means. Can gain the weight of the person.

A ninth aspect of the present disclosure is the seat for seating according to the eighth aspect, wherein the detection means outputs a load input to the seat cushion based on the detected electric resistance value.

In the seat for seating according to the ninth aspect, the detection means detects the electrical resistance value between the first electrode and the second electrode. The detecting means determines and outputs the load input to the seat cushion from the electrical resistance value between the first electrode and the second electrode. At this time, by detecting and storing in advance the displacement with respect to the load of the conductive elastic member and the electric resistance value with respect to the displacement, the detection means accurately determines the physique of the occupant seated on the seat cushion from the detected electric resistance value. Can output well.

A tenth aspect of the present disclosure is the seat for seating according to the seventh to ninth aspects, wherein the cushion pad is formed of urethane foam, and the conductive elastic member is formed of conductive urethane foam. .

In the seat for seating of the tenth aspect, a conductive elastic member formed of conductive urethane foam is provided on a cushion pad formed of urethane foam. Thereby, it is suppressed that cushion properties differ between a conductive elastic member and parts other than a conductive elastic member, and a favorable seating feeling is obtained.

Such a seat for seating according to the present disclosure can be applied as a vehicle seat provided in a vehicle such as an automobile. The seat for seating is not limited to a seat for a vehicle, but is used for seating a person such as a seat provided in an aircraft or a ship, a seat provided in an attraction of a game facility, or a seat provided in an entertainment facility such as a movie theater. It can be applied to various seats with cushioning properties.

As described above, the load sensor and the load detection device according to the present disclosure can detect the magnitude of the load with a simple configuration in which the pair of electrodes are brought into contact with the conductive elastic portion. In addition, the seat for seating of the present disclosure enables detection of whether a person is seated and whether the seated person is an adult or a child without impairing the sitting comfort.

Further, according to the present disclosure, a conductive elastic member is provided by disposing a mesh-like insulating sheet in which a plurality of openings are arranged between one of the first electrode and the second electrode and the conductive elastic member. It is possible to properly detect whether or not a load is input to the.

Further, according to the present disclosure, the first sheet and the second electrode with respect to the displacement of the conductive elastic member can be provided by providing the insulating sheet with a plurality of small holes that are smaller than the opening, around the opening. Since the change in electrical resistance value between the two electrodes can be increased, the range of loads that can be detected with high accuracy is widened.

1 is a schematic perspective view of a vehicle seat according to the present disclosure. It is a schematic sectional drawing along the width direction of the principal part of the seat cushion concerning this indication, and has shown the state where the load is not received. It is a schematic sectional drawing along the width direction of the principal part of the seat cushion concerning this indication, and shows an example of the state which received the load. It is a block diagram of the seating sensor which concerns on 1st Embodiment of this indication, and has shown the state which has not received the load. It is a lineblock diagram of a seating sensor concerning a 1st embodiment of this indication, and shows an example of a state which received load. It is a diagram which shows the outline of the change of the resistance value with respect to the compression amount of the electroconductive elastic part which concerns on 1st Embodiment of this indication. It is a schematic block diagram of the passenger | crew detection apparatus which concerns on 2nd Embodiment of this indication. It is a top view of an insulating sheet concerning a 2nd embodiment of this indication. It is an enlarged view of the principal part of the insulating sheet which concerns on 2nd Embodiment of this indication. It is a top view which shows the principal part of the electrode sheet which concerns on 2nd Embodiment of this indication. It is sectional drawing of FIG. 7A. It is the top view seen from the insulating sheet side which shows an example of the electrode network formed in an electrode sheet with the electrode thread | yarn which concerns on 2nd Embodiment of this indication. It is the top view seen from the insulating sheet side which shows the other example of the electrode network which concerns on 2nd Embodiment of this indication. It is the schematic which shows the change of the seating sensor according to the input load concerning 2nd Embodiment of this indication, the uppermost stage shows the state where the load is not inputted, and the load below the uppermost stage increases in order Shows the state. It is a diagram which shows the change of the resistance value with respect to the displacement based on 2nd Embodiment of this indication. It is a graph which shows the resistance value with respect to the change of a displacement based on 2nd Embodiment of this indication.

[First Embodiment]
Hereinafter, a first embodiment of the present disclosure will be described in detail with reference to the drawings. FIG. 1 shows a vehicle seat 10 as a seat for seating according to the present embodiment. The vehicle seat 10 is provided in a vehicle such as a passenger car and is used for seating a passenger of the vehicle. In FIG. 1, the front side in the longitudinal direction of the seat is indicated by an arrow FR, the width direction of the seat is indicated by an arrow W, and the upper side in the vertical direction of the seat is indicated by an arrow UP.

As shown in FIG. 1, the vehicle seat 10 includes a seat cushion 12, a seat back 14, and a headrest 16. In a vehicle provided with the vehicle seat 10, a slide mechanism including a pair of left and right slide rails 18 is fixed to the vehicle body. In the vehicle seat 10, for example, a cushion frame (not shown) that forms a skeleton of the seat cushion 12 is stretched around the slide rail 18. Thereby, the seat 10 for vehicles is supported by the slide rail 18, the vehicle seat 10 is movable to the vehicle front-back direction, and is fixed to a movement position.

In the vehicle seat 10, for example, a seat back frame (not shown) that forms a skeleton of the seat back 14 is connected to the cushion frame via a reclining mechanism (not shown) on the rear side of the seat cushion 12. Thus, the vehicle seat 10 is supported so that the seat back 14 can move to the slide rail 18 integrally with the seat cushion 12 and can be tilted. In the vehicle seat 10, the headrest 16 is integrally formed with the seat back 14 at the upper end portion of the seat back 14.

FIG. 2A and FIG. 2B show schematic cross sections of main portions of the seat cushion 12 of the vehicle seat 10 cut along the width direction. 2A shows a state where no occupant is seated, and FIG. 2B shows an example of a state where the occupant is seated.

The seat cushion 12 includes a cushion pad 20, and the surface of the cushion pad 20 is covered with a skin material 22. The vehicle seat 10 has a general configuration in which a cushion pad (not shown) of the seat back 14 and the headrest 16 is covered with a skin material 22.

The cushion pad 20 of the seat cushion 12 has, for example, convex portions formed on both sides in the width direction, and a flat portion is formed between the convex portions. As shown in FIG. 1, FIG. 2A, and FIG. 2B, the vehicle seat 10 is a side support portion 24 in which convex portions on both sides in the width direction of the seat cushion 12 are opposed to the side of the thigh of the occupant. The flat portion is a seat portion 26 on which an occupant is seated. Thus, the occupant seated on the vehicle seat 10 is supported by the seat cushion 12 at the seat portion 26 of the seat cushion 12, the back portion is supported by the seat back 14, and the head portion is supported by the headrest 16. Is done.

The vehicle seat 10 has the cushion pad 20 made of a material, cushioning properties, elastic characteristics and the like so that an occupant seated on the seat cushion 12 can have a comfortable sitting comfort and a comfortable riding comfort. As a result, as shown in FIG. 2B, in the state where the occupant is seated, the seat portion 26 of the seat cushion 12 is applied with a load according to the physique and weight of the seated occupant, and the cushion pad 20 is elastically deformed. In the present embodiment, urethane foam (soft urethane foam, foamed urethane) is used as the material of the cushion pad 20. In the present embodiment, urethane foam is applied as an example of an elastic member that forms a cushion pad of the vehicle seat 10.

On the other hand, FIGS. 3A and 3B show a schematic configuration of an occupant detection device 28 as a load detection device according to the present embodiment. The occupant detection device 28 includes a seating sensor 30 that detects the seating of the occupant on the vehicle seat 10 and an ECU (Electronic Control Unit) 32. In the present embodiment, the seating sensor 30 functions as an example of a load sensor, and the ECU 32 functions as an example of a detection unit. That is, in the present embodiment, the load sensor is applied to the seating sensor 30 of the vehicle seat 10.

1 and 2A, the seating sensor 30 includes an electrode 34 and an electrode 36 as a pair of electrodes. In the present embodiment, the electrodes 34 and 36 function as a pair of electrodes, the electrode 34 functions as an example of a first electrode, and the electrode 36 functions as an example of a second electrode.

As shown in FIG. 1, the electrodes 34 and 36 are provided corresponding to a region where a load is applied from an occupant seated on the vehicle seat 10. That is, in the vehicle seat 10, the seat portion 26 of the seat cushion 12 mainly receives a load from the occupant's buttocks. Thus, in the present embodiment, as an example, the electrodes 34 and 36 are disposed on the seat back 14 side of the seat portion 26 corresponding to the occupant's buttocks.

2A, the electrode 34 is disposed in close contact with the upper surface of the cushion pad 20, and is electrically connected to the cushion pad 20 that is in contact therewith. The electrode 34 is covered with the cushion pad 20 by the skin material 22. The electrode 34 is formed to have elasticity. For example, the electrode 34 is formed into a sheet shape by using a stretchable fabric such as spandex made of polyurethane elastic fiber and weaving a conductor into the stretchable fabric.

Thereby, as shown in FIG. 2B, when the cushion pad 20 is elastically deformed by receiving a load, the electrode 34 expands and contracts following the deformation of the surface of the cushion pad 20. The electrode 34 may be any sheet-like and stretchable structure, and may be formed in a conductive mesh shape, for example.

1 and 2A, the electrode 36 is disposed in close contact with the lower surface of the cushion pad 20, and is electrically connected to the cushion pad 20 in contact therewith. For this electrode 36, for example, a conductor formed in a sheet shape is used. The electrode 36 may be formed into a sheet shape by weaving a conductive material into a stretchable fabric, like the electrode 34, but is not limited thereto, and a general material using a metal that does not have stretchability is used. The target electrode can be applied. Further, the electrode 36 may have a smaller contact area than the electrode 34, for example, may be a point electrode, or a cushion frame using a conductive metal may be applied as the electrode 36.

On the other hand, on the cushion pad 20 of the seat cushion 12, a conductive elastic portion 38 using a conductive elastic member is formed at a portion between the electrodes 34 and 36. In the present embodiment, urethane foam (soft urethane foam) that is a polyurethane foam is used as the elastic member that forms the cushion pad 20. Accordingly, in the present embodiment, as an example of the conductive elastic member that forms the conductive elastic portion 38, a conductive urethane foam in which the urethane foam used for the cushion pad 20 is made conductive is used.

In general, urethane foam functions as an electrical insulator and has an extremely high electrical resistance (for example, a volume resistivity of 10 ¹¹ Ωm or more). The conductive urethane foam used for the conductive elastic portion 38 is obtained by, for example, supporting urethane carbon with conductive carbon particles such as carbon black. By containing conductive carbon particles such as carbon black, urethane foam The electrical resistance (for example, the volume resistivity is 10 ⁷ Ωm or less) is lowered. In addition, the conductive urethane foam is compressed according to the load received by receiving the load, and the electrical resistance value becomes smaller than the case where the conductive urethane foam is not compressed by being compressed. That is, the conductive urethane foam has a characteristic that the resistance value becomes small according to the compression amount.

Conductive urethane foam is widely used as a protective packaging material for electronic parts, an electronic shielding material, and the like. In this embodiment, the conductive urethane foam is used for the conductive elastic portion 38 provided between the electrodes 34 and 36 of the seating sensor 30. Yes. The conductive urethane foam according to this embodiment is manufactured by supporting conductive carbon particles such as carbon black on a urethane foam using a known method applied to the production of these conductive urethane foams. Applicable. In addition, the conductive urethane foam is not limited to the one using conductive carbon particles such as carbon black, and one obtained by imparting conductivity to the urethane foam by any method can be applied.

As a method of providing the conductive elastic portion 38 on the cushion pad 20 of the vehicle seat 10, the entire cushion pad 20 used for the seat cushion 12 may be foam-molded so as to be conductive. The conductive urethane foam may be fitted only in the corresponding part.

When obtaining the cushion pad 20 in which the conductive urethane foam is fitted in the portions corresponding to the electrodes 34 and 36, for example, the portion corresponding to the conductive elastic portion 38 is formed from the seat portion 26 of the cushion pad 20 formed of urethane foam. Cut out, and an opening corresponding to the conductive elastic portion 38 is formed in the cushion pad 20 and a block of urethane foam corresponding to the opening is formed. Thereafter, the urethane foam block is subjected to a treatment for providing conductivity, thereby forming the conductive elastic portion 38, and the formed conductive elastic portion 38 is fitted into the opening of the cushion pad 20. As a result, the cushion pad 20 in which the conductive elastic portion 38 is disposed at a portion corresponding to the electrodes 34 and 36 is obtained.

Further, when the cushion pad 20 in which the conductive urethane foam is fitted in the portions corresponding to the electrodes 34 and 36 is obtained, for example, the seat 26 of the cushion pad 20 formed of urethane foam corresponds to the conductive elastic portion 38. A part is cut out, and an opening corresponding to the conductive elastic portion 38 is formed in the cushion pad 20. Separately from the cushion pad 20, a urethane foam block having a shape corresponding to the opening is formed on the cushion pad 20, and the formed urethane foam block is subjected to a treatment to make it conductive. The elastic elastic portion 38 is formed, and the formed conductive elastic portion 38 is fitted into the opening of the cushion pad 20. Even if this method is used, the cushion pad 20 in which the conductive elastic portion 38 is disposed at the portion corresponding to the electrodes 34 and 36 is obtained.

3A and 3B, the occupant detection device 28 has electrodes 34 and 36 of a seating sensor 30 connected to the ECU 32. The ECU 32 detects the resistance value R between the electrodes 34, 36, that is, the resistance value R of the conductive elastic portion 38. Since the resistance value (resistance value R) of the compressed conductive elastic portion 38 is lower than the resistance value of the conductive elastic portion 38 in the non-compressed state (hereinafter referred to as resistance value R0), the resistance of the electrodes 34 and 36 is reduced. From the value R, it is detected whether or not the conductive elastic portion 38 receives a load, that is, whether or not an occupant is seated on the vehicle seat 10.

In addition, since the compression amount of the conductive elastic portion 38 changes depending on the load (weight), the ECU 32 determines that the occupant seated on the vehicle seat 10 is an adult who is a dwarf from the detected resistance value R. Determine if there is.

Here, as an operation of the present embodiment, detection of whether or not an occupant is seated on the vehicle seat 10 and determination of the physique (mainly weight) of the occupant when the occupant is seated will be described.

When the occupant is seated on the vehicle seat 10, the occupant is seated with the buttocks supported by the seat cushion 12 and the back supported by the seat back 14. Here, the vehicle seat 10 is elastically deformed by a load that the cushion pad 20 of the seat cushion 12 receives from the occupant's buttocks. Thereby, the passenger | crew who seated on the vehicle seat 10 can obtain a comfortable seating feeling, for example.

The seat cushion 12 is provided with a conductive elastic portion 38 on the seat portion 26 of the cushion pad 20, and the conductive elastic portion 38 is elastically deformed and compressed in accordance with the weight (load) received from the occupant when the occupant is seated. When the load is removed due to (volume compression) and the occupant stands up, the original volume is restored.

Here, in the seating sensor 30, the electrodes 34 and 36 are electrically connected to the conductive elastic portion 38 using conductive urethane foam, so that the electrode 34 and the electrode 36 are connected to the conductive elastic portion 38. The connection is made through a resistor having a resistance value R determined according to the thickness and the area of the electrodes 34 and 36 (contact area to the conductive elastic portion 38).

2B, when the load is applied, the conductive elastic portion 38 is elastically deformed and compressed according to the applied load. When the conductive elastic portion 38 is compressed and becomes thin, the resistance value R decreases. The ECU 32 to which the seating sensor 30 is connected detects the resistance value R between the electrodes 34 and 36 that changes due to the load received by the conductive elastic portion 38.

If the conductive elastic portion 38 is D0 (see FIG. 3A) when the conductive elastic portion 38 is in a non-compressed state, and D1 (see FIG. 3B) when the conductive elastic portion 38 is compressed under a load, the load is received. The compression amount C of the conductive elastic portion 38 is C = D0−D1.

FIG. 4 shows an outline of a change in the resistance value R of the conductive elastic portion 38 with respect to the compression amount C. The resistance value R of the conductive elastic portion 38 decreases as the input load increases and the compression amount C increases. Accordingly, in the seating sensor 30, the resistance value R between the electrodes 34 and 36 changes according to the compression amount C of the conductive elastic portion 38, that is, the load input to the conductive elastic portion 38, and the load increases. As the resistance value R decreases.

The ECU 32 determines whether or not the conductive elastic portion 38 is elastically deformed (compressed) by detecting the resistance value R between the electrodes 34 and 36. For example, the ECU 32 stores the resistance value R0 between the electrodes 34 and 36 in the non-compressed state (compression amount C = 0) of the conductive elastic portion 38, and detects when the resistance value R between the electrodes 34 and 36 is detected. It is determined whether or not an occupant is seated on the vehicle seat 10 by comparing the resistance value R with the stored resistance value R0. Thus, when the resistance value R is lower than the resistance value R0 (R <R0), the ECU 32 determines that an occupant is seated on the vehicle seat 10.

When it is determined that the occupant is seated on the vehicle seat 10, the ECU 32 determines the weight of the occupant seated on the vehicle seat 10 from the detected resistance value R. The determination of the weight of the occupant is performed by, for example, measuring the weight of the occupant seated on the vehicle seat 10 and the resistance value R corresponding to the weight in advance, thereby defining a characteristic curve or map of the resistance value with respect to the weight and storing it in the ECU 32. Keep it. Thus, the ECU 32 determines the approximate weight of the occupant seated on the vehicle seat 10 from the detected resistance value R, and outputs the determination result.

In addition, the weight differs between an adult (for example, an age of 12 years or older) and a child (dwarf, for example, an age of 6 years or more and less than 12 years), and even an adult has a different weight depending on the physique. From here, based on the resistance value R, the physique of the passenger seated on the vehicle seat 10 may be determined.

The resistance value R when an adult is seated is smaller than the resistance value R when a dwarf is seated. Further, even for an adult, the resistance value R is smaller when a large (heavy) adult is seated than a small (light) adult.

From here, for example, as shown in FIG. 4, a threshold value in a plurality of stages may be set for the resistance value R. In FIG. 4, as an example, the threshold value Rt1 or less, the threshold value Rt2 or more is a small person, the threshold value Rt2 or less, the threshold value Rt3 or more is an adult having a physique smaller than the average physique, the threshold value Rt3 or less The threshold Rt4 or higher is set to be classified as an adult of average physique, less than the threshold Rt4, and the threshold Rt5 or higher is classified as an adult having a larger physique than the average physique. In addition, less than threshold value Rt5 may be included in an adult with a large physique, and may be classified as an adult with a very large physique.

Thereby, the ECU 32 determines the approximate weight of the occupant seated on the vehicle seat 10 from the detected resistance value R, and outputs the determination result. When an infant is seated on the vehicle seat 10, an infant restraint device (CRS: Child Restorant System, hereinafter referred to as a child seat) called an infant assist device is attached to the vehicle seat 10. The resistance value R detected by the ECU 32 becomes smaller than the resistance value R0 when the child seat is attached to the vehicle seat 10, and the resistance value R further decreases when the infant is placed on the child seat. When the ECU 32 detects a change in the resistance value R by an incorporated algorithm, the ECU 32 may determine that an infant is placed on the vehicle seat 10 and output the detected result.

Thus, based on the weight or physique of the occupant determined and output by the ECU 32, for example, by controlling the operation of occupant protection means such as an airbag device provided in the vehicle, the vehicle seat 10 Appropriate protection for passengers seated in the vehicle is possible.

Here, in the present embodiment, as an example, one electrode 34 is disposed in the conductive elastic portion 38. However, the present invention is not limited to this. For example, one electrode 34 is divided into a plurality of small electrodes by dividing it vertically and horizontally. And a plurality of small electrodes are arranged in a matrix on the conductive elastic portion 38, or one electrode 34 is divided into a plurality of small electrodes and the conductive elastic portion 38 corresponds to each of the small electrodes. And may be divided. When the conductive elastic portion 38 is divided, an insulating material (non-conductive elastic member, for example, a sheet-like urethane foam) having a cushioning property equivalent to that of the conductive elastic portion 38 is provided between the divided conductive elastic portions 38. ) Or an insulating material having a cushioning property (softer) higher than that of the conductive elastic portion 38 is preferably interposed. The ECU 32 is connected to a plurality of divided small electrodes separately. When the electrode 36 is divided, the ECU 32 may detect the resistance value between each of the small electrodes and the electrode 36 in order so as to scan vertically and horizontally. In addition, when the conductive elastic portion 38 is divided and an insulation is interposed between the divided conductive elastic portions 38, the ECU 32, for example, sets the resistance value between each of the small electrodes and the electrode 36 in parallel. And then detect it. Thus, the ECU 32 can obtain whether or not the occupant is seated on the vehicle seat 10 and the load distribution received from the seated occupant in addition to the occupant when the occupant is seated. Such load distribution can be applied to determination of the physique of a seated passenger.

In addition, in this Embodiment demonstrated above, although the seating sensor 30 as a load sensor was arrange | positioned and demonstrated to the seat cushion 12 of the vehicle seat 10, the attachment position of a load sensor is not restricted to this. For example, in the seat back 14 of the vehicle seat 10, a load sensor having the same configuration as the seating sensor 30 may be provided at a position corresponding to the back of the occupant. An occupant seated on the vehicle seat 10 applies a load to the seat back 14 from the back by sudden acceleration of the vehicle. From here, the load which the seat back 14 receives from a passenger | crew's back part can be detected by providing a load sensor in the seat back 14. FIG.

[Second Embodiment]
Hereinafter, a second embodiment of the present disclosure will be described with reference to FIGS. 5 to 10B. Note that only the parts different from the first embodiment will be described in detail, and the same parts and symbols will be used for the common parts, and the description thereof will be omitted.

The occupant detection device 128 according to the second embodiment of the present disclosure is disposed on the seat cushion 12 of the vehicle seat 10 in the same manner as the occupant detection device 28 of the first example shown in FIGS. However, in the occupant detection device 128 according to the second embodiment, the electrode part 134 is different from the electrode 34 of the occupant detection device 28 in the first embodiment.

FIG. 5 is a schematic configuration diagram illustrating an occupant detection device 128 according to the second embodiment of the present disclosure. The occupant detection device 128 is provided with a seating sensor 130 as a load sensor in place of the seating sensor 30 of the first embodiment, and an ECU 32 as a load output unit.

The seating sensor 130 is provided with an electrode part 134 provided with a first electrode, an electrode 36 as a second electrode, and a conductive elastic part 38 using a conductive elastic member. The electrode part 134 and the electrode A conductive elastic portion 38 is disposed between the conductive elastic portion 38 and the conductive elastic portion 38.

Here, a conductive metal material such as iron or aluminum is applied to the electrode 36. Further, the electrode 36 has an arbitrary shape that can be electrically connected to the conductive elastic portion 38. As such an electrode 36, a metal plate such as iron having a thickness of about 0.3 mm to 1.0 mm can be formed into a pan shape (flat plate shape, concave shape) by press forming. Moreover, the electrode 36 may be applied with a mesh shape (punching metal) in which perforations having a predetermined shape are uniformly formed in a press-formed metal plate.

Further, the vehicle seat 10 is provided with a metallic seat pan below the seat cushion 12, and the seat pan contacts the lower surface of the cushion pad 20 to support the cushion pad 20. A sheet pan can be used for the electrode 36, and in the present embodiment, a sheet pan is used for the electrode 36. The electrode 36 is not limited to a sheet pan as long as it is electrically connected to the lower surface of the conductive elastic portion 38, and a sheet carrying a conductor or a general electrode using metal is applied. be able to. Further, even if the cushion frame is not provided with a seat pan, when the cushion frame is made of metal, the electrode 36 may be a cushion frame.

On the other hand, the electrode part 134 of the seating sensor 130 is provided with an electrode sheet 40 and an insulating sheet 42 as an insulating sheet. In the electrode part 134, the insulating sheet 42 is disposed on the conductive elastic part 38 side, and the electrode sheet 40 is superimposed on the insulating sheet 42. The electrode sheet 40 and the insulating sheet 42 cover the upper surface of the conductive elastic portion 38 in a region where the seat cushion 12 receives a load from the occupant.

The insulating sheet 42 is made of a sheet that has insulating properties such as an insulating resin film, a woven fabric, and a knitted fabric, and is stretchable and formed in a mesh shape. FIG. 6A shows a plan view of an insulating sheet 42 using a woven fabric as an example, and FIG. 6B shows an enlarged view of a main part of the insulating sheet 42 shown in FIG. 6A. In FIG. 6, as an example, a tulle mesh (trade name manufactured by Toray, model number # 2070) that is a woven fabric using polyester fibers is shown, and in FIG. 6B, the white portion shows fibers (woven yarn), The black part has shown the space | gap (opening).

The insulating sheet 42 is formed in a mesh shape by providing openings as openings (hereinafter referred to as openings 44) arranged vertically and horizontally. Generally, the size (size) of openings formed by arranging wire rods (woven yarns) vertically and horizontally is represented by the interval (opening width) between the vertical and horizontal wire rods. In a mesh in which openings are formed, the opening ratio ε is obtained from the thickness of the wire and the opening width of the openings.

As shown in FIG. 6B, in the present embodiment, the diameter (inner diameter IDa) of the inscribed circle 46 of the opening 44 is used as the size of the opening 44 (size of the opening). The opening ratio ε of the opening 44 (hereinafter referred to as the opening ratio ε1) is the ratio of the total area of openings (opening 44) per unit area (1 square inch) (the area of the opening 44 relative to the unit area). %) Is applied.

Here, as the insulating sheet 42, it is preferable to apply a mesh-like insulating sheet in which the inner diameter IDa of the inscribed circle 46 is in the range of IDa = 20 μm to 2.0 mm (2000 μm). As the insulating sheet 42, an insulating sheet having an opening ratio ε per unit area of the opening 44 and the small hole 44A described below in the range of ε = 20% to 80% is preferably used. Further, the insulating sheet 42 has a thickness of 20 μm to 2.0 mm in a portion excluding the opening 44 and the following small hole 44A.

Also, the insulating sheet 42 is provided with a plurality of small holes 44A as small holes, and each of the small holes 44A is opened around the opening 44 smaller than the opening 44. In the present embodiment, the size of the opening of the small hole 44A is indicated by the diameter (inner diameter IDb) of an inscribed circle 46A that is a circle in contact with the peripheral edge of the opening similarly to the opening 44. The inscribed circles 46 and 46A are the circles having the largest diameter among the circles in contact with at least two points on the periphery in each of the opening 44 and the small hole 44A.

The insulating sheet 42 has an inner diameter IDb of an inscribed circle 46A of the small hole 44A and an opening ratio ε (hereinafter referred to as an opening ratio ε2) of the small hole 44A per unit area (1 square inch). The aperture ratio ε2 of the small hole 44A is a percentage of the total area (opening area) of the small hole 44A with respect to the unit area, and the area of the portion other than the small hole 44A includes the area of the opening 44.

As the insulating sheet 42, an insulating sheet having a thickness, an inner diameter IDa of the opening 44, and an opening ratio ε of the opening 44 according to the outer diameter of the following electrode yarn 50 is used within the above range. As the insulating sheet 42, an insulating sheet having a thickness, an inner diameter IDb of the small hole 44A, and an opening ratio ε of the small hole 44A according to the outer diameter of the electrode yarn 50 described below is used.

When a woven fabric and a knitted fabric are applied as the insulating sheet 42, the fiber yarn (woven yarn) forming the woven fabric and the knitted fabric is a synthetic fiber (resin) such as nylon (may be nylon 6 or nylon 66) fiber or polyester fiber. Fiber). The insulating sheet 42 can be made of synthetic fibers such as polyolefin fibers such as polyethylene (PE) and polypropylene (PP). The insulating sheet 42 is woven or knitted so that the openings 44 and the plurality of small holes 44A are formed by these synthetic fiber yarns or yarns formed by twisting synthetic fibers. At this time, the stretchability of the insulating sheet 42 is improved by weaving the yarn so that the small holes 44A are continuous in a chain.

The electrode sheet 40 is formed by a base 48 as a stretchable sheet and an electrode thread 50 as a conductive thread forming the first electrode. 7A is a plan view of the main part of the electrode sheet 40, and FIG. 7B is a cross-sectional view of the main part of the electrode sheet 40 shown in FIG. 7A along the sewing direction of the electrode thread 50. It is shown.

The electrode sheet 40 is a sheet in which the base 48 has stretchability and insulation, and the base 48 preferably has a stretch rate of 130% or more, and a fabric (cloth) such as spandex. ) And resin films are applied. In the present embodiment, as an example of the substrate 48, a spandex having an expansion ratio equal to or greater than that of the skin material 22 of the seat cushion 12 is used.

The electrode yarn 50 is formed by vapor-depositing a conductive metal on a fiber yarn, and conductivity is imparted by the metal vapor-deposited on the fiber yarn. Natural fibers may be used for the fiber yarns, but artificial fibers are preferable because metal deposition is performed, and synthetic fibers (resin fibers) such as polyester fibers are applied. The electrode yarn 50 is formed by twisting a plurality of (for example, two or three) fiber yarns, and the wire diameter (outer diameter) is in a range of 0.1 mm to 1.0 mm by metal deposition. Can be used. Moreover, as a metal vapor-deposited on a fiber thread | yarn, the alloy etc. which were formed by combining arbitrary metals, such as silver (Ag), gold | metal | money (Au), nickel (Ni), or multiple types of metals, etc. can be used.

In the seating sensor 130, the outer diameter of the electrode yarn 50 and the sizes of the opening 44 and the small hole 44A of the insulating sheet 42 are associated with each other. For example, the insulating sheet 42 is provided with an opening 44 in which the inner diameter IDa of the inscribed circle 46 is at least larger (including slightly larger) than the outer diameter of the electrode yarn 50, and the inner diameter IDa of the inscribed circle 46 is provided. Is more preferably provided with an opening 44 that is twice or more the outer diameter of the electrode yarn 50. The insulating sheet 42 is provided with a plurality of small holes 44A in which the inner diameter IDb of the inscribed circle 46A is smaller than the inner diameter IDa of the opening 44, and the inner diameter IDb of the inscribed circle 46A is an electrode thread. It is approximately the same as or slightly smaller than the outer diameter of 50. That is, the small hole 44 </ b> A has an inner diameter IDb that is equal to or smaller than the outer diameter of the electrode yarn 50.

In the electrode sheet 40, an electrode thread 50 is sewn into the base 48 and arranged. Arbitrary patterns can be applied to the wiring of the electrode yarn 50 to the substrate 48, but the area of the electrode yarn 50 appearing on the insulating sheet 42 side is large (long) and the stretchability of the substrate 48 is impaired. A pattern with no is preferred.

FIG. 7A shows an example of the pattern of the electrode yarn 50 arranged on the substrate 48 in a plan view viewed from the insulating sheet 42 side. 7B is a cross-sectional view of the main part of FIG.

As shown in FIG. 7A, in this embodiment, a staggered pattern 52 is applied as a pattern (stitch pattern) for sewing the electrode thread 50 into the substrate 48. The staggered pattern 52 is obtained by alternately sewing the electrode threads 50 on the left and right sides around the wiring 54 with respect to the virtual wiring 54 along the sewing direction of the electrode thread 50. Yes. That is, the staggered pattern 52 is so-called zigzag stitching that is zigzag stitched so that the electrode threads 50 (stitches of the electrode threads 50) intersect the wiring 54.

In the staggered pattern 52, the base 48 may be sewn with the electrode thread 50 on both the left and right sides of the wiring 54. Instead of scooping the base 48 with the electrode thread 50, the electrode thread 50 may be sewn with the base 48. You may be allowed to pass through. Further, when one electrode yarn 50 is inserted, the length of the electrode yarn 50 that appears on the insulating sheet 42 side of the substrate 48 is shortened. From here, the two electrode yarns 50 may be used, and the two electrode yarns 50 may be sewn into the substrate 48 so as to alternately appear on the insulating sheet 42 side. Thereby, since the gap between the stitches of the electrode thread 50 appearing on the insulating sheet 42 side can be continuously formed without opening, the length of the electrode thread 50 on the insulating sheet 42 side can be increased, and the insulating sheet 42 side The surface area of the electrode yarn 50 can be increased.

As shown in FIG. 7B, in this embodiment, an electrode thread 50 and a non-conductive thread (hereinafter referred to as a locking thread 50A) are used. As the locking yarn 50A, any yarn can be used, and the fiber yarn before metal vapor deposition used for the electrode yarn 50 can be used. In the staggered pattern, the electrode yarn 50 is routed on one surface of the substrate 48, and the locking yarn 50A is routed on the other surface. At this time, the electrode thread 50 sewn into the substrate 48 is sewed together by the locking thread 50A sewn into the substrate 48 from the opposite side of the electrode thread 50, so that the electrode thread 50 and the locking thread 50A are sewn into the substrate 48. . As a result, the electrode yarn 50 is routed on one surface of the substrate 48, and the locking yarn 50 </ b> A is routed on the other surface of the substrate 48.

In addition, as a method of routing the electrode yarn 50 on the substrate 48 with the staggered pattern 52, the electrode yarn 50 and the engagement yarn 50A are held on both the left and right sides of the routing wire 54 so that the electrode yarn 50 is wound. The stop yarns 50 </ b> A may be locked to the substrate 48. As a method of wiring the electrode yarn 50 on the substrate 48 with the staggered pattern 52, contrary to the above-described method, the electrode yarn 50 is used to squeeze the locking yarn 50A on both the left and right sides of the wiring 54. The electrode yarn 50 and the locking yarn 50A may be locked to the substrate 48.

Here, as shown in FIG. 7A, the stitch interval ND of the electrode thread 50 can be about ND = 3 mm to 5 mm, and the stitch width is a dimension in a direction intersecting the routing line 54 of the electrode thread 50. NW can be about NW = 3 mm to 5 mm. Further, if the angle α (see FIG. 7A) between the electrode yarns 50 adjacent to each other along the wiring 54 is too narrow (too small), the base 48 is expanded or contracted in the direction in which the electrode yarn 50 intersects the wiring 54. If the angle α is too wide (too large), the electrode yarn 50 may suppress the expansion and contraction of the substrate 48 in the direction along the wiring 54. Accordingly, the angle α is preferably in the range of 30 ° to 150 °. Further, by determining the stitch interval ND and the angle α, the length L of the electrode thread 50 for one stitch in the staggered pattern 52, that is, the stitch width NW of the staggered pattern 52 is determined. Accordingly, the staggered pattern 52 has a stitch interval ND and a stitch width NW that are set so that the stretchability of the substrate 48 is not impaired and the length of the electrode yarn 50 that appears on the insulating sheet 42 side is increased. It is determined and formed on the substrate 48.

In the electrode sheet 40, the staggered pattern 52 is applied as a pattern for arranging the electrode yarns 50, so that the vertical and horizontal stretchability of the substrate 48 into which the electrode yarns 50 are sewn can be prevented from being impaired. In the electrode sheet 40, the electrode thread 50 is sewn into a region of the substrate 48 (for example, substantially the entire region of the substrate 48) corresponding to a region where a load is input to the conductive elastic portion 38. As a result, an electrode network as a first electrode is formed on the substrate 48. FIG. 8A and FIG. 8B are plan views showing an example of an electrode network applicable in the present embodiment.

In the electrode network 56 shown in FIG. 8A, straight wiring lines 54A and 54B are set in a lattice form vertically and horizontally at a predetermined stitch interval SD. In the electrode network 56, the electrode thread 50 is sewn by the staggered pattern 52 along each of the plurality of wirings 54 </ b> A and 54 </ b> B.

When the interval between the adjacent wiring lines 54A (or the wiring lines 54B) is the stitch interval SD (the stitch interval SD1 of the routing line 54A, the stitch interval SD2 of the routing line 54B), the stitch interval SD is If it is narrow, it will affect the stretchability of the substrate 48, and if the stitch interval SD is wide, the arrangement of the electrode threads 50 will be sparse. From here, the electrode mesh 56 has a stitch interval SD set in a range of SD = 1 cm to 10 cm (SD1 = 1 cm to 10 cm, SD2 = 1 cm to 10 cm).

In the electrode network 58 shown in FIG. 8B, a plurality of wiring lines 54C each having a different radius are set concentrically. In the electrode network 58, a plurality of straight wiring lines 54D are set radially from the center position of the wiring line 54C. In the electrode network 58, the electrode yarns 50 are routed by being sewn by the staggered pattern 52 along each of the routing lines 54C and 54D. In the electrode network 58, the interval between the adjacent wiring lines 54C is set as the stitch interval SD, and the electrode network 58 has a plurality of wiring lines 54C so as to have the stitch interval SD (SD = 1 cm to 10 cm). Each radius is set.

In the electrode sheet 40, the stitch interval SD is set together with the stitch width NW and the stitch interval ND of the staggered pattern 52 so that the electrode threads 50 are evenly arranged in a predetermined region to form the electrode nets 56 and 58. Is done. At this time, the electrode yarn 50 faces or is adjacent to part or all of the openings 44 of the insulating sheet 42, and the electrode yarn 50 faces or is adjacent to part or all of the small holes 44 </ b> A.

In this embodiment, an electrode network 56 is formed on the electrode sheet 40 as an example of the first electrode. The electrode sheet 40 may be formed with an electrode network having a combination of the electrode networks 56 and 58, such as disposing the electrode network 56 around the outer periphery of the electrode network 58. In addition, the electrode sheet 40 may be formed with an electrode network in the form of an oblique lattice in which each of the straight wiring lines 54A and 54B is inclined.

In the seating sensor 130, an insulating sheet 42 having elasticity is disposed on the conductive elastic portion 38, and the electrode sheet 40 is overlapped on the insulating sheet 42, so that the conductive elasticity is passed through the electrode sheet 40 and the insulating sheet 42. A load is input to the portion 38. As a result, even if the upper surface of the conductive elastic portion 38 is undulated by the input load (displacement due to elastic compression), the insulating sheet 42 is brought into close contact with the upper surface of the conductive elastic portion 38, and the electrode sheet 40. The electrode yarn 50 is brought into close contact with the insulating sheet 42.

In the occupant detection device 28, the electrode yarns 50 arranged on the electrode sheet 40 of the seating sensor 130 are collectively connected and electrically connected to the ECU 32. Thereby, the ECU 32 can detect the resistance value between the electrode part 134 and the electrode 36 by electrically connecting the electrode part 134 and the electrode 36 to the conductive elastic part 38. The resistance value between the electrode portion 134 and the electrode 36 detected by the ECU 32 changes according to the thickness displacement amount when the conductive elastic portion 38 is elastically deformed, and is detected as the displacement amount increases. The resistance value becomes lower. Further, the resistance value detected by the ECU 32 changes according to the contact area of the electrode yarn 50 of the electrode part 134 that is in contact with the conductive elastic part 38, and becomes lower than when the contact area is widened.

The ECU 32 measures the displacement of the conductive elastic portion 38 with respect to the load and the resistance value between the electrode portion 134 and the electrode 36 with respect to the displacement of the conductive elastic portion 38 in advance, and stores it as a map of the load with respect to the resistance value, for example. Yes. The ECU 32 determines the resistance value between the electrode part 134 and the electrode 36 and the load input to the conductive elastic part 38 from the map of the load with respect to the resistance value stored in advance, that is, the weight of the occupant seated on the vehicle seat 10. judge.

Next, the operation of the present embodiment will be described.
The seat cushion 12 of the vehicle seat 10 is provided with the conductive elastic portion 38 of the seating sensor 130 together with the cushion pad 20. When the occupant sits on the seat cushion 12, the conductive elastic portion 38 becomes the physique (weight) of the occupant. ) To be elastically deformed and compressed. Thereby, in the seating sensor 130, the resistance value of the conductive elastic portion 38 between the electrode portion 134 and the electrode 36 changes. The ECU 32 of the occupant detection device 28 detects the resistance value between the electrode part 134 and the electrode 36 of the seating sensor 130 and is seated on the seat cushion 12, that is, the load input to the conductive elastic part 38 from the detected resistance value. Determine the weight (physique) of the occupant.

Here, a conductive urethane foam is used for the conductive elastic portion 38, and the conductive urethane foam has the same elastic characteristics as the cushion pad 20 of the seat cushion 12. In addition, the electrode portion 134 of the seating sensor 130 uses a stretchable substrate 48 for the electrode sheet 40 and a stretchable fabric for the insulating sheet 42. As a result, the seat cushion 12 is restrained from changing its elastic characteristics from the original elastic characteristics, so that the seating sensor 130 causes a comfortable feeling of loss of sitting comfort to the occupant seated on the seat cushion 12. Can be prevented.

Further, in the seating sensor 130, the electrode yarn 50 is routed on the base 48 of the electrode sheet 40 provided on the seat cushion 12, and the electrode yarn 50 is easily cut when it is thin (for example, the outer diameter is less than 0.1 mm). . In addition, if the electrode thread 50 is thick (for example, if the outer diameter is about several millimeters), the passenger sitting on the seat cushion 12 may feel uncomfortable. On the other hand, in the seating sensor 130, the electrode yarn whose wire diameter (outer diameter) is in the range of 0.1 mm to 1.0 mm (0.1 mm or more and 1.0 mm or less) by metal deposition of the fiber yarn. 50 is used. Accordingly, the seating sensor 130 does not cause the occupant seated on the seat cushion 12 to feel uncomfortable with the electrode thread 50 provided on the electrode seat 40. Therefore, the vehicle seat 10 can give the passenger a comfortable feeling of sitting comfortably even if the seating sensor 130 is provided.

Furthermore, in the passenger detection device 128 of the present embodiment, a seat pan provided on the seat cushion 12 is used as the electrode 36. The seat pan has a position and shape that takes into account the seating comfort of the occupant seated on the vehicle seat 10, and the vehicle seat 10 uses the seat pan as the electrode 36 to provide a seating sensor 130. In addition, changes in the seating comfort of the seat cushion 12 are suppressed. The occupant detection device 128 can eliminate the need for a dedicated electrode (second electrode) by using the seat pan as the electrode 36.

On the other hand, FIG. 9 shows an outline of the change in accordance with the load in the seating sensor 130. The uppermost stage shows a state in which no load is input (hereinafter referred to as a no-load state). The side shows a state in which the input loads are sequentially increased. In FIG. 9, the magnitude of the load is indicated by the thickness of the two-dot chain line arrow, and the thick arrow indicated by the two-dot chain line indicates that the input load is larger than the thin arrow. .

The conductive elastic portion 38 used for the seating sensor 130 is elastically compressed when a load is input. At this time, the displacement (thickness displacement) due to the elastic compression of the conductive elastic portion 38 is determined by the load-displacement characteristic of the conductive urethane foam, but increases as the input load increases. In addition, even when the conductive elastic portion 38 is in a no-load state, if the electrode portion 134 and the electrode 36 are electrically connected, a predetermined resistance value (volume resistivity and Resistance value according to thickness) occurs. Furthermore, the conductive elastic portion 38 changes in electrical resistance value due to displacement.

9, the electrode part 134 of the seating sensor 130 is provided with an insulating sheet 42 between the conductive elastic part 38 and the electrode sheet 40 provided with the electrode thread 50. For this reason, when the electrode portion 134 is in a no-load state, the electrode yarn 50 is separated from the conductive elastic portion 38 and is electrically disconnected. Thereby, in the seating sensor 130, since the insulating sheet 42 is disposed between the conductive elastic portion 38 and the electrode sheet 40 (electrode yarn 50), the resistance value between the electrode portion 134 and the electrode 36 becomes extremely large. ing.

Further, the insulating sheet 42 has a mesh shape in which openings 44 serving as openings are arranged, and a small hole 44A having an opening smaller than the opening 44 is formed. A load is input to the conductive elastic portion 38 via the electrode sheet 40 and the insulating sheet 42. At this time, substantially the entire upper surface of the conductive elastic portion 38 is pressed from the insulating sheet 42, but the force received by the region facing the opening 44 and the small hole 44A is lower than the force received by the surroundings.

Here, the conductive urethane foam forming the conductive elastic portion 38 has softness and repulsive force. When the load is input, if the input load is different, the input is made. A region with a large load is deformed (depressed) more than a region with a small input load. Therefore, as shown in the second row from the top in FIG. 9, when the input load is relatively small, the conductive elastic portion 38 is formed in the opening 44 that is opened larger than the small hole 44A. A part of the surface layer portion of the conductive urethane foam enters into the opening 44, particularly into the inscribed circle 46 of the opening 44. Further, the electrode sheet 50 is pressed toward the insulating sheet 42 by the input load. As a result, the conductive elastic portion 38 comes into contact with a part of the electrode yarn 50 facing the opening 44 in the opening 44 of the insulating sheet 42 and is electrically connected to the electrode yarn 50. Therefore, in the seating sensor 130, the resistance value between the electrode part 134 and the electrode 36 is greatly reduced as compared with the case where no load is input. That is, in the seating sensor 130, when a load is input to the conductive elastic portion 38, the resistance value between the electrode portion 134 and the electrode 36 is greatly reduced as compared to the case of no load.

Further, when the input load is increased, the conductive elastic portion 38 is also applied to the electrode yarn 50 in the peripheral portion of the opening 44 that is the peripheral portion of the opening 44 of the insulating sheet 42 and outside the inscribed circle 46. Touched. Further, the conductive elastic portion 38 enters the small hole 44A and contacts the electrode yarn 50 facing the inscribed circle 46A that is a large opening portion in the small hole 44A. That is, the conductive urethane foam forming the conductive elastic portion 38 enters the small hole 44A due to its softness and repulsive force, and contacts a part of the electrode yarn 50 on the upper side of the small hole 44A.

For this reason, as shown in the third row from the top in FIG. 9, the conductive elastic portion 38 that has entered the small hole 44A of the insulating sheet 42 and the electrode yarn 50 that is positioned opposite the small hole 44A are provided. Touch and be electrically connected. Accordingly, in the seating sensor 130, the displacement of the conductive elastic portion 38 is increased as compared with a case where the load is small, and the area of the electrode yarn 50 that contacts the conductive elastic portion 38 is increased. As a result, the resistance value between the electrode portion 134 and the electrode 36 changes due to the change in the resistance value of the conductive elastic portion 38 and the resistance value resulting from the increase in the contact area between the conductive elastic portion 38 and the electrode yarn 50. Changes. Therefore, the resistance value between the electrode part 134 and the electrode 36 is further reduced as compared with the case where the load is small.

Further, as shown in the lowermost stage of FIG. 9, when the input load further increases, the conductive elastic portion 38 further enters the small hole 44 </ b> A formed in the insulating sheet 42. For this reason, the conductive elastic portion 38 contacts the electrode yarn 50 at the peripheral edge portion of the small hole 44A. As a result, the displacement of the conductive elastic portion 38 increases and the contact area between the conductive elastic portion 38 and the electrode yarn 50 further increases, and the seating sensor 130 further increases the resistance value between the electrode portion 134 and the electrode 36. descend.

Therefore, in the seating sensor 130, the contact area between the conductive elastic portion 38 and the electrode yarn 50 changes according to the load, so that the resistance value between the electrode portion 134 and the electrode 36 is limited only to the displacement of the conductive elastic portion 38. It changes greatly compared to the corresponding change in resistance value.

Here, FIGS. 10A and 10B show an example of the measurement result of the resistance value between the electrode part 134 and the electrode 36 with respect to the displacement of the conductive elastic part 38 in the seating sensor 130 according to the present embodiment. FIG. 10A shows a change in resistance value (resistance value R (Ω)) with respect to the displacement (mm) of the conductive elastic portion 38 in a diagram, and FIG. 10B shows a displacement in the diagram in FIG. 10A. The measured value of the resistance value R (Ω) with respect to is shown in the chart. In addition, the measurement of the resistance value against the displacement and the load is performed three times. FIGS. 10A and 10B show that the first measurement result is N1, the second measurement result is N2, and the third measurement result is N3. Is shown. Furthermore, in FIG. 10A, the change of the resistance value R with respect to the displacement of the conductive elastic portion 38 as a comparative example is indicated by a two-dot chain line. The comparative example has a configuration in which the insulating sheet 42 is removed from the seating sensor 130, that is, even if no load is input, the electrode yarn 50 of the electrode sheet 40 is formed on the conductive elastic portion on the substantially entire surface on the conductive elastic portion 38 side. 38 is electrically connected.

In the measurement, as the conductive elastic portion 38 of the seating sensor 130, a conductive urethane foam having a hardness at IDL of 25% (hardness according to the apparent density hardness test D method of JIS K6401) is 220N. For the conductive elastic portion 38, a sample having a length and width of 400 mm and a height (thickness) of 100 mm (400 mm × 400 mm × height 100 mm) is used. As the electrode 36, an iron seat pan provided on the seat frame of the seat cushion 12 is used.

In addition, the electrode part 134 uses the electrode sheet 40 and the insulating sheet 42 having a size covering the sample of the conductive elastic part 38. The base 48 of the electrode sheet 40 is made of spandex, the electrode yarn 50 is made of polyethylene terephthalate (PET) fiber, and the electrode yarn 50 is silver-deposited yarn formed by twisting two polyethylene terephthalate fibers. Thus, the thickness (outer diameter) is 300 μm. Further, a staggered pattern 52 having a stitch interval ND = ND = 3 mm and a stitch width NW = NW = 3 mm is applied to the electrode sheet 40, and the electrode thread 50 is placed so that the stitches on the insulating sheet 42 side are substantially continuous. An electrode network 56 is formed by sewing into the substrate 48. The electrode network 56 is sewn into the substrate 48 so that the vertical and horizontal stitch intervals SD (SD1, SD2) are SD (= SD1 = SD2) = 3 cm.

The insulating sheet 42 is made of a woven fabric using polyester fibers (trade name: tulle mesh, model # 2070 manufactured by Toray). In the opening 44 of the insulating sheet 42, the inner diameter IDa of the inscribed circle 46 is IDa = 500 μm, and the inner diameter IDa of the inscribed circle 46 is larger than the outer diameter of the electrode yarn 50. The insulating sheet 42 is provided with a plurality of small holes 44A around the opening 44. The small holes 44A have an inner diameter IDb of the inscribed circle 46A that is slightly smaller than the outer diameter of the electrode yarn 50. Yes. The insulating sheet 42 has a thickness T (pressurized average thickness defined in JIS L1096) T of T = 250 μm.

The insulating sheet 42 has a ratio of the area (opening area) of only the opening 44 per unit area as an opening ratio ε1, and a ratio of the area (opening area) of only the small holes 44A per unit area as an opening ratio ε2. The aperture ratio ε1 = 37.81% and the aperture ratio ε2 = 6.87%. The insulating sheet 42 has an opening ratio ε = 44.68 (= ε1 + ε2), where the ratio of the area of the opening 44 and the small hole 44A per unit area (unit area) is the opening ratio ε. Yes.

Further, when the average value of the inner diameter IDa of the inscribed circle 46 of the opening 44 and the inner diameter IDb of the inscribed circle 46A of the small hole 44A in the unit area is defined as the average diameter AID, the insulating sheet 42 has an average thickness T. It is made larger than the diameter AID. At this time, in each of the openings 44, the inner diameter IDa of the inscribed circle 46 is larger than the average diameter AID, and in each of the small holes 44A, the inner diameter IDb of the inscribed circle 46A is smaller than the average diameter AID.

As the aperture ratios ε, ε1, and ε2, a general method of calculating the number of pixels by counting the number of pixels on image data obtained by imaging the target insulating sheet 42 can be used. For imaging, a stereomicroscope (Leica M125C) capable of capturing images is used, and imaging is performed at an arbitrary magnification. The obtained image data is subjected to image processing such as rotation, inversion, trimming, contrast adjustment, etc. using general image processing software to clarify the shading. Cut out the image data for the aperture ratio calculation target area from the image data obtained in this way, paint the opening part black, and then convert the black part of the opening part and the white part of the fiber part to image data (See FIG. 6B), and then converted into bitmap data. The number of black and white pixels is counted from the bitmap data, and the number of pixels in the unit area, the number of pixels in the opening 44 in the unit area, and the number of pixels in the small holes 44A in the unit area are counted. The aperture ratios ε, ε1, and ε2 are calculated based on the obtained count values. The size of the opening 44 of the insulating sheet 42 (inner diameter IDa of the inscribed circle 46) and the size of the small hole 44A (inner diameter IDb of the inscribed circle 46A) are also acquired from the image data of the captured image of the insulating sheet 42. can do.

In the comparative example, each of the electrode yarn 50 and the electrode 36 of the electrode portion 134 is in electrical contact with and electrically connected to the conductive elastic portion 38 even in a no-load state. As a result, as shown in FIG. 10A, in the comparative example, a resistance value of the conductive elastic portion 38 is generated between the electrode portion 134 and the electrode 36 even in a no-load state. Further, in the comparative example, when a load is input and a displacement occurs in the conductive elastic portion 38, only the resistance value corresponding to the displacement of the conductive elastic portion 38 is detected, so the resistance value when the displacement changes The change is small.

On the other hand, in the seating sensor 130, since the insulating sheet 42 is provided between the electrode yarn 50 and the conductive elastic portion 38, the electrode yarn 50 and the conductive elastic portion of the electrode portion 134 are not loaded. Since the insulating sheet 42 is interposed between the electrode portion 134 and the electrode 36, the resistance value between the electrode portion 134 and the electrode 36 is extremely high as compared with the comparative example.

In the seating sensor 130, when a load is input to the conductive elastic portion 38, a part of the electrode yarn 50 corresponding to the opening 44 of the insulating sheet 42 and the conductive elastic portion 38 are electrically connected. Is done. Thereby, in the seating sensor 130, the electroconductive elastic part 38 and the electrode thread | yarn 50 are electrically connected, and the resistance value between the electrode part 134 and the electrode 36 falls large. Therefore, the ECU 32 can accurately determine whether or not a load is input from the change in the resistance value between the electrode portion 134 and the electrode 36, and the occupant detection device 28 determines whether or not the occupant is seated on the vehicle seat 10. Can be accurately detected.

Further, in the seating sensor 130, when the load input to the conductive elastic portion 38 through the electrode sheet 40 and the insulating sheet 42 of the electrode portion 134 increases, the conductive elastic portion 38 (conductive urethane) increases with the increase in the load. Foam) enters the opening 44 and also enters the small hole 44A. That is, the seating sensor 130 is provided with the opening 44 and the small hole 44 </ b> A in the insulating sheet 42, so that when the load input to the conductive elastic portion 38 is large, the conductive elasticity is larger than when the load is small. The area of the electrode yarn 50 in contact with the portion 38 increases.

For this reason, in the seating sensor 130, the displacement of the conductive elastic portion 38 increases as the input load increases, and the contact area of the electrode yarn 50 to the conductive elastic portion 38 increases. Thereby, in the seating sensor 130, the change in the resistance value R with respect to the displacement of the conductive elastic portion 38 is larger than that in the comparative example.

On the other hand, in the seating sensor 130, the electrode sheet 40 and the insulating sheet 42 are overlapped, and the electrode sheet 40 may slightly shift with respect to the insulating sheet 42 when a load is input. For this reason, the position of the electrode yarn 50 with respect to each of the opening 44A and the small hole 44A of the insulating sheet 42 may be shifted, and when the position of the electrode yarn 50 with respect to each of the opening 44A and the small hole 44A is shifted, A change occurs in the contact area between the conductive elastic portion 38 and the electrode yarn 50 with respect to the load.

Here, in the seating sensor 130, the variation of the resistance value R with respect to the displacement in each of the first to third times is within 10%. The change in the resistance value R due to the displacement of the position of the electrode yarn 50 with respect to each of the opening 44A and the small hole 44A of the insulating sheet 42 is suppressed.

Further, in the insulating sheet 42, the inner diameter IDa of the inscribed circle 46 of the opening 44 is larger than the outer diameter of the electrode yarn 50, and the inner diameter IDb of the inscribed circle 46A of the small hole 44A is outside the electrode yarn 50. It is smaller than the diameter. The insulating sheet 42 has a thickness T larger than the average diameter AID. As a result, the load input to the conductive elastic portion 38 gradually increases, so that the conductive elastic portion 38 and the electrode yarn 50 are gradually in contact with each other through the opening 44 and the small hole 44A. It is done. At this time, in the region where the input load is low, the opening 44 mainly contributes to the contact between the conductive elastic portion 38 and the electrode yarn 50, and the conductive elastic portion 38 is connected to the electrode yarn through the opening 44. 50 is contacted. Further, in the region where the input load is high, the small hole 44A contributes to an increase in the contact between the conductive elastic portion 38 and the electrode yarn 50, and the conductive elastic portion 38 and the electrode yarn 50 through the opening 44. The contact between the conductive elastic portion 38 and the electrode yarn 50 via the small hole 44A is added to the contact with the electrode yarn 50.

Thus, by making the thickness T of the insulating sheet 42 larger than the average diameter AID, the seating sensor 130 can increase the slope of the resistance value with respect to the displacement as compared with the comparative example. At this time, by appropriately combining the thickness T of the insulating sheet 42 and the average diameter AID, the resistance value range (change range) with respect to the displacement of the conductive elastic portion 38 can be widened.

Accordingly, in the seating sensor 130, the range of the resistance value with respect to the displacement of the conductive elastic portion 38 can be widened, and the variation in the resistance value with respect to the displacement is small, so the load input to the conductive elastic portion 38 is determined from the resistance value. Accuracy can be improved. Further, the occupant detection device 28 using the seating sensor 130 can improve detection accuracy when detecting the physique of the occupant seated on the vehicle seat 10.

The design of the vehicle seat 10 may use an occupant dummy seated on the seat. The occupant dummy includes a child dummy and an adult dummy. The adult dummy includes an adult female dummy and an adult male dummy. May be used. A child dummy (P-6) corresponding to a 6-year-old child has a height of 120 cm and a weight of 22 kg. The adult female dummy (AF05) has a physique with a height of 145 cm and a weight of 45 kg, and the adult male dummy (AM50) has a physique with a height of 175 cm and a weight of 78 kg.

FIG. 10A shows displacements Ld1 to Ld3 of the conductive elastic portion 38 when it is assumed that the dummy is seated on the vehicle seat 10. FIG. The displacement amount Ld1 corresponds to the displacement amount of the child dummy (9 mm), the displacement amount Ld2 corresponds to the displacement amount of the adult female dummy (34 mm), and the displacement amount Ld3 corresponds to the displacement amount of the adult male dummy (58 mm). It is supported.

Here, in the seating sensor 130, the difference in resistance value R corresponding to each of the displacement amounts Ld1 to Ld3 is clear, and the resistance value R of the displacement amounts Ld1 to Ld3 divided into at least three stages is clearly identified. be able to. From this, by dividing the range of the displacement amount with reference to the displacement amounts Ld1 to Ld3, it is possible to determine from the resistance value R which of the displacement amounts Ld1 to Ld3 the displacement amount belongs to.

As a result, the occupant detection device 128 using the seating sensor 130 is not in two stages of whether the occupant seated on the vehicle seat 10 is an adult or a child, but is a child physique, an adult female physique, and an adult male. Can be divided into three stages of occupants of the physique. Further, it is obvious that the occupant detection device 128 can identify the occupant's physique not only in three stages but also in four or more stages.

In this way, the seating sensor 130 arranges the insulating sheet 42 in which the openings 44 are arranged in a mesh shape between the electrode yarn 50 forming the first electrode and the conductive elastic portion 38, It is possible to accurately detect a load that causes displacement in the conductive urethane foam. Further, by operating the occupant protection device according to the occupant's physique detected by the occupant detection device 128, the seated occupant is appropriately protected by the occupant protection device in the vehicle seat 10.

At this time, the size of the opening portion 44 of the insulating sheet 42, the size of the small hole 44A, the opening ratios ε, ε1, ε2, the outer diameter of the electrode yarn 50, and the sewing pattern of the electrode yarn 50 are changed to the conductive elastic portion 38. By setting according to the softness and the repulsive force, the change width of the resistance value with respect to the change of the displacement of the conductive elastic portion 38 can be set.

Note that, as described in the first embodiment, when an infant is seated on the vehicle seat 10, the child seat is attached to the vehicle seat 10. The resistance value detected by the ECU 32 is smaller when the child seat is attached to the vehicle seat 10 than when the child seat is not attached, and when the infant is placed on the child seat, the resistance value is reduced. Further decrease. By incorporating such an algorithm for detecting a change in resistance value into the ECU 32, it is possible to accurately determine that the infant is placed on the child seat mounted on the vehicle seat 10, and appropriate protection of the infant placed on the child seat is achieved. It becomes possible.

In the present embodiment described above, the electrode yarn 50 in which a conductive metal material is deposited on the fiber yarn is used as the conductive yarn. However, the conductive yarn is not limited to the electrode yarn 50. The conductive yarn may be a thread-like material carrying conductivity, may be a fiber yarn coated with metal, or formed by twisting a plurality of metal coated fiber yarns It may be. The conductive yarn may be a metal yarn formed by stretching a metal material into a thin line shape, or may be formed by twisting a plurality of metal yarns. Further, the conductive yarn may be formed by twisting a fiber yarn carrying conductivity and a non-conductive fiber yarn.

Moreover, in this Embodiment demonstrated above, although the insulating sheet 42 was arrange | positioned between the electrode thread | yarn 50 and the electroconductive elastic part 38, not only this but the insulating sheet 42 is the electrode 36 and the electroconductive elastic part 38. You may arrange | position between. By providing the insulating sheet 42 between the electrode 36 and the conductive elastic portion 38, the contact area of the electrode 36 with respect to the load input to the conductive elastic portion 38 can be easily grasped, and a desired resistance value R for displacement can be obtained. It is easy to design a seating sensor to obtain changes.

Moreover, in 1st and 2nd embodiment of this indication, the urethane foam is used for the cushion pad 20 as an elastic member, The electroconductive urethane foam which made the electroconductive elastic part 38 the electroconductive urethane foam as an electroconductive elastic member However, the material of the elastic member and the conductive elastic member is not limited to this. As the elastic member, a known material used for the sheet can be applied, and as the conductive elastic member, it is preferable to apply an elastic member having conductivity to the elastic member used for the sheet.

In the first and second embodiments of the present disclosure described above, the vehicle seat 10 has been described as an example. However, the vehicle seat may have a configuration that does not have a reclining function. In addition, seats for seating are not limited to seats for vehicles, but are not limited to automobiles, such as seats provided at attractions of railway vehicles, ships, aircraft, amusement facilities, seats provided at entertainment facilities such as movie theaters, etc. Applies to any seat with cushioning properties. In this embodiment, the load sensor is used as a seating sensor. However, the load sensor can be provided in any mechanism that receives a load, and the received load can be applied to the determination.

The disclosures of Japanese Patent Application No. 2015-203892 filed on October 15, 2015 and Japanese Patent Application No. 2016-159309 filed on August 15, 2016 are hereby incorporated by reference in their entirety. Is taken in.

All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims (10)

1. A first surface to which a load is input and a second surface opposite to the first surface are provided, and elastically compressed according to the input load, so that the space between the first surface and the second surface is A conductive elastic member whose electrical resistance value changes;
   A first electrode provided to face the first surface;
   A second electrode provided to face the second surface and electrically connected to the first electrode via the conductive elastic member;
   Load sensor with
2. An insulating sheet provided between the conductive elastic member and at least one of the first electrode and the second electrode as a mesh in which a plurality of openings of a predetermined size are arranged;
   The first electrode and the second electrode can be electrically connected through a part of the conductive elastic member entering each of the plurality of openings by being elastically compressed.
   The load sensor according to claim 1.
3. The insulating sheet is provided with a plurality of small holes having an opening smaller than the opening around each of the plurality of openings.
   The first electrode and the second electrode can be electrically connected through a part of the conductive elastic member entering each of the plurality of small holes by being elastically compressed.
   The load sensor according to claim 2.
4. Further comprising a stretchable sheet disposed to face the first surface of the conductive elastic member;
   The first electrode is formed by sewing a conductive thread into the stretchable sheet.
   The load sensor according to any one of claims 1 to 3.
5. The load sensor according to any one of claims 1 to 4,
   Detection means for detecting an electrical resistance value between the first electrode and the second electrode;
   Including a load detecting device.
6. The load detection device according to claim 5, wherein the detection means determines the load from the electric resistance value.
7. A seat for seating provided with the load sensor according to any one of claims 1 to 4,
   The conductive elastic member is provided on the cushion pad of the seat cushion,
   The seat for seating, wherein the first surface is an upper surface of the cushion pad and the second surface is a lower surface of the cushion pad.
8. The seat for seating according to claim 7, wherein the first electrode and the second electrode are connected to detection means for detecting an electric resistance value between the first electrode and the second electrode.
9. The seat for seating according to claim 8, wherein the detection means outputs a load input to the seat cushion based on the detected electric resistance value.
10. The seat for seating according to any one of claims 7 to 9, wherein the cushion pad is made of urethane foam, and the conductive elastic member is made of conductive urethane foam.

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