JP2018040596A - Load detection sensor and load detection sensor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a load detection sensor and a load detection sensor unit which can be reduced in size, while precisely detecting a load.SOLUTION: A load detection sensor 5A includes: a first electrode 56e and a second electrode 57e which face each other at a predetermined interval via an opening 58C provided in a spacer 58; and a metal plate 60 for covering at least a part of the second electrode 57e from a side opposite to the spacer 58. In the metal plate 60, a plurality of slits 60S are formed in a region overlapping with the opening 58C other than the center of the opening 58C.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a load detection sensor and a load detection sensor unit, and is suitable for downsizing.

  As one of safety systems in vehicles, an alarm system for warning that a seat belt is not worn when riding is put into practical use. In this alarm system, a warning is issued when the seat belt is not detected while a person is seated. As a device for detecting the seating of the person, a seating detection device that detects a load caused by the seating may be used.

  As a seating detection device, a spacer in which an opening is formed is arranged between a pair of resin films, and electrodes formed on the respective films are opposed to each other with a predetermined interval in the opening of the spacer. A device using a load detection sensor is known. However, a resin film generally tends to bend with a weak force due to a decrease in strength when the temperature rises. Therefore, when placed in an environment where the temperature is high, such as in an automobile under a hot sun, the strength of the resin film may decrease as described above. In this case, even when a load lighter than a normal human load is applied to the seat device, there is a possibility of erroneously detecting the seating.

  Patent Document 1 below describes a seating sensing device that can suppress the above-described erroneous detection. In the load detection sensor used in this seating detection device, a metal plate is disposed on the surface of the load detection sensor on the opposite side of the spacer from the spacer side so as to cover the opening.

  According to this seating detection device, since the metal plate has elasticity and the elasticity does not change so much with temperature, the metal plate suppresses how the film bends at the time of seating detection changes with temperature. The Therefore, according to the seating sensor, it is possible to suppress the load for detecting the seating from changing due to the temperature.

  However, when a metal plate such as the seating detection device described in Patent Document 1 below is provided, the film is more difficult to bend than when no metal plate is provided, and the load detection unit is difficult to turn on. There is concern that it will be difficult. For this reason, the load detection sensor unit described in Patent Document 2 below includes a pressing member having a pressing portion that is harder than the seat cushion, and the pressing portion presses a part of the metal plate to form a pair. The electrodes are in contact with each other.

  According to the load detection sensor unit, the metal plate can be bent more appropriately than when the seat cushion directly presses the metal plate, and the load can be detected appropriately. Further, since a metal is less likely to creep than a resin, even if a part of the metal is pressed by the pressing member, it is difficult for the metal plate to stick. Therefore, according to the load detection sensor unit, it is possible to appropriately detect the load, and to suppress erroneous detection of the load due to a pushing rod or the like.

Japanese Patent No. 0532548 International Publication No. 2016/121835

  Incidentally, there is a case where a load detection sensor such as a seating sensor is required to be downsized. In that case, it is conceivable to reduce the opening of the spacer facing the pair of electrodes described in each of the above patent documents. However, if the opening is made small, the metal plate becomes difficult to bend, and it becomes difficult to detect the load with an appropriate load. For this reason, it is conceivable to make the metal plate thin. However, if the metal plate is made thin, creep is likely to occur, and there is a concern that a load may be erroneously detected by a pusher or the like.

  Then, an object of this invention is to provide the load detection sensor and load detection sensor unit which can be reduced in size, detecting a load appropriately.

  In order to solve the above problems, a load detection sensor according to the present invention includes a pair of electrodes facing each other with a predetermined interval through an opening provided in a spacer, and at least a part of one of the pair of electrodes. And a metal plate covering the metal plate from the opposite side of the spacer, wherein the metal plate has a plurality of slits formed in a region overlapping the opening except for the center of the opening.

  According to such a load detection sensor, when the metal plate is pressed, one electrode is bent, the one electrode and the other electrode come into contact with each other, and the switch is turned on. By the way, even when the temperature changes, the flexibility of the metal does not change so much as described above. Therefore, even when the environmental temperature around the load detection sensor changes, the bending method of the metal plate does not change so much. Therefore, according to this load detection sensor, erroneous detection of the load can be suppressed even when the environmental temperature changes.

  Further, since a plurality of slits are formed in the metal plate, the strength of elasticity of the metal plate can be adjusted by adjusting the size and number of the slits without reducing the thickness of the metal plate. In addition, the slit is not formed in a region overlapping the center of the opening of the spacer in the metal plate. The position overlapping with the center of the opening of the metal plate is a position that is most bent when the load is detected, and one electrode can be appropriately pressed at this position. For this reason, even when the load detection sensor is downsized and the opening of the spacer is made small, the metal plate can be appropriately bent while suppressing the generation of the pushing rod, and the load is detected appropriately. be able to.

  Moreover, it is preferable that at least two of the plurality of slits are formed at symmetrical positions with respect to the center.

  In this case, the bending of the metal plate can be made symmetric with respect to the center of the opening. Accordingly, it is possible to suppress a decrease in load detection accuracy due to a biased way of bending of the electrode. More preferably, each of the plurality of slits is formed at a symmetrical position with respect to the center.

  Moreover, it is preferable that the plurality of slits are formed so as to spread radially from the center.

  In this case, the density of the metal located on the center side of the opening of the spacer in the metal plate is smaller than the density of the metal located on the outer peripheral side of the opening, and the metal plate can be easily bent toward the center side of the opening. In addition, stress tends to concentrate on the portion of the metal plate located near the opening edge of the spacer. However, as described above, the metal density increases on the outer peripheral side of the opening. Can be further suppressed.

  Moreover, it is preferable that at least two of the plurality of slits are formed in parallel to each other.

  In this case, the metal plate tends to bend more easily in the direction perpendicular to the direction in which the mutually parallel slits extend than in the direction in which the mutually parallel slits extend. Accordingly, the metal plate is restored by the repulsive force of the metal plate in the direction in which the slits parallel to each other extend while sufficiently imparting the deflection necessary to turn on the switch in the direction perpendicular to the direction in which the slits extend. Can be suppressed. More preferably, each of the plurality of slits is formed in parallel with each other.

  Moreover, it is preferable that at least one of the plurality of slits extends to a region that does not overlap the opening.

  In this case, it becomes easy to bend appropriately from the position where a metal plate overlaps with an opening edge. Therefore, the load can be detected more appropriately. It is more preferable that each of the plurality of slits extends to a region that does not overlap with the opening.

  In order to solve the above problems, a load detection sensor unit according to the present invention presses a load detection sensor according to any one of the above, a pressure receiving surface that receives a load, and a position that overlaps a center of the opening in the metal plate. And a pressing member having a pressing portion whose contact area with the metal plate is smaller than that of the pressure receiving surface.

  According to such a load detection sensor unit, the load received by the pressure receiving surface is transmitted to the pressing portion whose contact area with the metal plate is smaller than the area of the pressure receiving surface, so that the load received in a wide area is concentrated on the pressing portion. can do. Therefore, the metal plate can be bent more appropriately, and the load can be detected more appropriately.

  In the load detection sensor unit, it is preferable that the pressure receiving surface receives a load due to a pressing force from a seat cushion, and the pressing portion is harder than the seat cushion.

  Such a load detection sensor unit is disposed under the seat cushion. Accordingly, the pressure receiving surface of the pressing member receives a pressing force from the seat cushion, and the pressing portion presses the metal plate by the pressing force. Therefore, the metal plate can be bent more appropriately by the pressing member harder than the seat cushion, and the load can be detected more appropriately.

  As described above, according to the present invention, it is possible to provide a load detection sensor and a load detection sensor unit that can be downsized while appropriately detecting a load.

It is a figure which shows the load detection sensor unit in 1st Embodiment. It is an exploded view of the load detection sensor unit of FIG. It is sectional drawing which shows a mode that the load detection sensor unit was attached to S spring. It is an exploded view of a load detection sensor. It is a front view of a load detection sensor. It is sectional drawing which shows a mode that protective resin is fixed to a support plate. It is a figure which shows typically the mode of the support plate arrange | positioned between the spring parts in two S springs which mutually oppose when the upper part of S spring is planarly viewed. It is a figure which shows typically the mode of the support plate arrange | positioned between the spring parts which mutually oppose in one S spring when the upper part of S spring is planarly viewed. It is a figure which shows the mode of the ON state of a load detection sensor. It is an exploded view which shows the structure of the load detection sensor unit concerning 2nd Embodiment of this invention. It is sectional drawing which shows a mode that the load detection sensor unit of FIG. 10 was attached to S spring. It is an exploded view which shows the structure of the load detection sensor of FIG. It is sectional drawing in the XX line of the load detection sensor of FIG. It is sectional drawing in the YY line of the load detection sensor of FIG. It is a figure which shows the equivalent circuit of the load detection sensor of FIG. It is a figure which shows the ON state of the load detection sensor of FIG. It is a figure which shows the load detection sensor of 3rd Embodiment of this invention from the same viewpoint as FIG. It is a figure which shows the 1st modification of a load detection sensor. It is a figure which shows the 2nd modification of a load detection sensor. It is a figure which shows the 3rd modification of a load detection sensor.

  Hereinafter, a preferred embodiment of a load detection sensor unit according to the present invention will be described in detail with reference to the drawings. For ease of understanding, the scale of each figure may be different from the scale described in the following description.

(First embodiment)
FIG. 1 is a diagram showing a load detection sensor unit in the present embodiment, FIG. 2 is an exploded view showing the configuration of the load detection sensor unit in FIG. 1, and FIG. It is sectional drawing which shows a mode that it attached. As shown in FIGS. 1 to 3, the load detection sensor unit 1A includes a support plate 2A, a pair of buffer members 3A, an upper case 4A, and a load detection sensor 5A as main components.

  As shown in FIG. 2, the support plate 2 </ b> A has a placement portion 21 on which the load detection sensor 5 </ b> A is placed, and a pair of hook portions 22 connected to the placement portion 21. The mounting portion 21 includes a wide main block mounting portion 21m and a tail block mounting portion 21t extending from the main block mounting portion 21m and having a narrower width than the main block mounting portion 21m. In the present embodiment, the hook portion 22 is connected to the main block placement portion 21m. Moreover, in this embodiment, the mounting part 21 and a pair of hook part 22 are integrally shape | molded by bending a metal plate. The plate thickness of the support plate 2A is set to 0.8 mm, for example.

  On the surface of the main block placement portion 21m facing the seat cushion SC, a main block 50m provided with a switch SW that is used as a pressure sensor in a load detection sensor 5A described later is disposed. Further, as shown in FIG. 2, a plurality of circular through holes 20H penetrating the support plate 2A are formed in the main block mounting portion 21m, and a plurality of generally rectangular case stopping openings 24 are formed. Yes.

  As shown in FIG. 3, the main block mounting portion 21m is between two S springs 100 facing each other among a plurality of S springs 100 that are arranged and stretched over the opening of the seat frame in the vehicle seat device. The size is such that it can be placed. The S spring 100 is a spring meandering in an S shape.

  The tail block mounting portion 21t has a substantially rectangular shape, and extends in a direction substantially perpendicular to the direction connecting the pair of hook portions 22 when the main block mounting portion 21m is viewed in plan. The tail block mounting portion 21t is connected to the main block mounting portion 21m in a state in which the surface direction is inclined with respect to the surface direction of the main block mounting portion 21m by bending a metal plate. A tail block 50t on which wiring is provided in a load detection sensor 5A described later is disposed on the surface of the tail block placement portion 21t facing the seat cushion SC. In the present embodiment, the width in the direction perpendicular to the extending direction of the tail block mounting portion 21t is made smaller than the width of the tail block 50t of the load detection sensor 5A, and the extending direction of the tail block mounting portion 21t. Is made smaller than the length of the tail block 50t of the load detection sensor 5A.

  The pair of hook portions 22 are respectively connected to side portions of the main block mounting portion 21m facing each other across the main block mounting portion 21m. The pair of hook portions 22 are respectively hooked on spring portions that are parts of the two S springs 100 facing each other.

  In addition, the pair of hook portions 22 have the same configuration and have an inner wall portion 22A, an outer wall portion 22B, and an upper wall portion 22C. A part of the S spring 100 is disposed in a space surrounded by the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C. A buffer member 3A is disposed between a part of the S spring 100 and the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C. That is, each hook part 22 is configured to be able to hook and hold a spring part via the buffer member 3A by the inner wall part 22A, the outer wall part 22B, and the upper wall part 22C.

  The inner wall portion 22A extends along a direction substantially orthogonal to the main block placement portion 21m and is connected to the main block placement portion 21m. The upper wall portion 22C is positioned above the placement surface of the main block placement portion 21m, extends substantially parallel to the placement surface, and is connected to the inner wall portion 22A. The outer wall portion 22B is inclined with respect to the direction orthogonal to the placement surface on the placement surface side of the main block placement portion 21m and extends closer to the main block placement portion 21m toward the tip. ing. In the present embodiment, an opening 22H is formed from the inner wall portion 22A to the outer wall portion 22B.

  Further, the hook portion 22 has elasticity, and when the buffer member 3A is disposed in the space surrounded by the inner wall portion 22A, the upper wall portion 22C, and the outer wall portion 22B as described above, the inner wall portion 22A, The upper wall portion 22C and the outer wall portion 22B are configured to contact a part of the buffer member 3A. A pressing portion 22PT hook is formed below the outer wall portion 22B. The pressing portion 22PT is bent so as to protrude toward the main block mounting portion 21m, and the buffer member 3A is moved to the main block by the elasticity of the hook portion 22. The force which presses on the mounting part 21m side works. Thus, the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C of the hook portion 22 extend so as to cover a part of the S spring 100, and the S spring 100 is located on the upper side, the main block placement portion 21m side, and It can be fastened through the buffer member 3A from three directions opposite to the main block placement portion 21m.

  Each buffer member 3 </ b> A is a member that softens the contact between the support plate 2 </ b> A and the S spring 100. These buffer members 3A are arranged as described above in the space surrounded by the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C of the hook portion 22 of the support plate 2A.

  Each buffer member 3A has a buffer body 31, a pair of locking claws 32, and a pair of guides 33. These buffer body 31, the locking claws 32, and the guide 33 are formed by integral molding. Has been.

  The buffer main body 31 has a substantially U-shaped cross section, and is formed with a groove 31A into which a part of the S spring 100 can be fitted. In a state where the S spring 100 is disposed in the groove 31A, the inner wall of the buffer body 31 forming the groove 31A is sandwiched between the S springs 100, and the S spring 100 is fitted to the buffer body 31.

  Further, the locking claws 32 are provided on the side wall on the outer side of the buffer body 31 on the side wall on the main block mounting portion 21m side and on the side wall opposite to the main block mounting portion 21m side, respectively. . The locking claw 32 formed on the side wall on the main block placement portion 21m side has the buffer body 31 disposed in a space surrounded by the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C of the hook portion 22. In this state, it can be hung on the edge of the inner wall portion 22A with the opening 22H. The locking claw 32 formed on the side wall opposite to the main block placement portion 21m side can be hooked on the edge of the outer wall portion 22B with the opening 22H in a state where the buffer main body 31 is disposed in the space. Is done.

  Further, the pair of guides 33 are formed on the outer side wall of the buffer body 31 from the main block placement portion 21m side to the opposite side of the main block placement portion 21m side. The distance between the guides 33 is substantially the same as the width of the hook portion 22, and the buffer body 31 is disposed in a space surrounded by the inner wall portion 22A, the outer wall portion 22B, and the upper wall portion 22C of the hook portion 22. In this state, the hook portion 22 is sandwiched between the pair of guides 33. Therefore, in a state where the buffer member 3A is attached to the hook portion 22, the positional deviation between the buffer member 3A and the hook portion 22 is suppressed.

  Further, in a state where the S spring 100 is fitted in the groove 31A of the buffer body 31, the support plate 2A and the S spring 100 are fixed in a fixed positional relationship via the buffer member 3A. In this state, when the pressing portion 22PT of the hook portion 22 presses the buffer member 3A toward the S spring 100, the support plate 2A and the S spring 100 are firmly fixed.

  The buffer member 3A has a hardness smaller than the hardness of the support plate 2A. Examples of the material of the buffer member 3A include acrylonitrile, butadiene, styrene copolymer synthetic resin (ABS), polyamide (PA), polypropylene (PP), and polyacetal (POM). Examples of the material of the support plate 2A include spring steel and stainless steel.

  The Rockwell hardness of the buffer member 3A is preferably about HRR30 to HRR120, and the Rockwell hardness of the support plate 2A is preferably about HRB80 to HRC68. In addition, when the Rockwell hardness of the buffer member 3A is in the range of HRR30 to HRR120, it is preferable because noise due to contact between the support plate 2A and the S spring 100 can be further reduced and deformation of the buffer material due to the load can be suppressed. . Further, when the Rockwell hardness of the support plate 2A is in the range of HRB80 to HRC68, the support plate 2A is softer than the S spring 100 but has sufficient durability, which is preferable.

  The upper case 4A is a member that covers the main block 50m placed on the main block placement portion 21m of the placement portion 21 and protects the switch SW and the like of the main block 50m. Further, as shown in FIG. 3, the upper case 4A is also a pressing member that presses the switch SW of the load detection sensor 5A when pressed by the seat cushion SC.

  The upper case 4 </ b> A has a top wall 45 and a frame wall 48. In the present embodiment, the top wall 45 is a plate-like member that is generally rectangular. Further, the frame wall 48 of the upper case 4 </ b> A is divided into a plurality of parts and connected to the top wall 45 along the outer periphery of the top wall 45. A hook piece 47 is connected to the top wall 45 between each of the frame walls 48 divided into a plurality. Each hook piece 47 is configured to be fitted into the case stop opening 24 in the main block placement portion 21m of the support plate 2A. By fitting each hook piece 47 into the case stopping opening 24, relative movement of the support plate 2A and the upper case 4A in the mounting surface direction of the main block mounting portion 21m is restricted.

  The top wall 45 of the upper case 4A is provided with a pressing portion 46 that protrudes from the bottom surface on the side facing the mounting portion 21 of the support plate 2A. The front end of the pressing portion 46 has a planar shape. The tip of the pressing part 46 may be a convex curved surface.

  Further, the top wall 45 of the upper case 4A is provided with a plurality of ribs 49 protruding from the same bottom surface as the side on which the pressing portion 46 is provided. These ribs 49 are formed at positions that overlap with the plurality of through holes 20H formed in the placement portion 21 of the support plate 2A. In a state where the upper case 4A covers the load detection sensor 5A placed on the placement portion 21 of the support plate 2A and the respective hook pieces 47 are fitted in the respective case stop openings 24, the respective ribs 49 penetrate through the corresponding ribs 49. It is inserted into the hole 20H. Thereby, even if the load detection sensor 5A is not bonded to the placement portion 21, the relative movement in the direction of the placement surface between the switch SW of the load detection sensor 5A and the pressing portion 46 of the upper case 4A is restricted. The In the case of the present embodiment, in the state where the upper case 4A covers the load detection sensor 5A placed on the placement portion 21 and the hook pieces 47 corresponding to the respective case stop openings 24 are fitted, The tip is in contact with the load detection sensor 5A, but may not be in contact.

  The upper case 4A is made of a material harder than the seat cushion SC. Therefore, the pressing part 46 which is a part of the upper case 4A is also formed of a material harder than the seat cushion SC. Since the seat cushion SC is generally made of foamed urethane resin, the material of the upper case 4A is polycarbonate (PC), polyimide (PI), polybutylene terephthalate (PBT), phenol resin, epoxy resin, etc. These resins are mentioned.

  When such a load detection sensor unit 1A is attached to a pair of S springs 100 as shown in FIG. 3, the upper surface 45S of the top wall 45 of the upper case 4A is at a predetermined distance from the lower surface of the seat cushion SC. Opposite with a gap. The upper surface 45S is planar. The upper surface 45S is a pressure receiving surface that receives pressure from the seat cushion SC, and the area of the upper surface 45S is larger than the area of the portion of the pressing portion 46 that contacts the metal plate 60 of the load detection sensor 5A.

  The load detection sensor 5A disposed between the support plate 2A and the upper case 4A is a sheet-like sensor having a switch SW that is a pressure-sensitive sensor, and includes a flexible switch sheet 50, a metal plate 60, and the like. And an adhesive layer 70 for bonding the switch sheet 50 and the metal plate 60 to each other. The switch sheet 50 and the metal plate 60 are bonded together by the adhesive layer 70. In FIG. 2, the adhesive layer 70 is omitted.

  The switch seat 50 is a membrane switch, and includes a substantially rectangular main block 50m and a tail block 50t that is connected to the main block 50m and is narrower than the main block 50m. The main block 50m is also a main block of the load detection sensor 5A, and the tail block 50t is also a tail block of the load detection sensor 5A. The main block 50m is provided with a switch SW. The tail block 50t is connected to the main block 50m and extends away from the main block 50m. Further, through holes 50H are formed in the vicinity of each vertex of the main block 50m.

  As shown in FIG. 3, the metal plate 60 is attached to one surface of the switch sheet 50 by the adhesive layer 70. In the present embodiment, the metal plate 60 is attached to the surface of the main block 50m that is a part of the switch seat 50 on the seat cushion SC side.

  Next, the load detection sensor 5A will be described in more detail with reference to FIG.

  FIG. 4 is an exploded view of the load detection sensor 5A. As shown in FIG. 4, the switch sheet 50 includes a first electrode sheet 56, a spacer 58, and a second electrode sheet 57. The first electrode sheet 56 mainly includes a first insulating sheet 56s, a first electrode 56e, and a first terminal 56c.

  The first insulating sheet 56s is a flexible resin insulating sheet. The first insulating sheet 56s includes a main block 56m having the same shape as the main block 50m of the switch seat 50, and a tail block 56t connected to the main block 56m and having substantially the same shape as the tail block 50t of the switch seat 50. The shape of the tail block 56t is different from the shape of the tail block 50t of the switch seat 50 in that the tip portion on the opposite side of the main block 56m is narrower than the other portions of the tail block 56t. The main block 56m has a through hole 56H formed at the same position as the through hole 50H of the switch seat 50. Examples of the material of the first insulating sheet 56s include resins such as polyethylene terephthalate (PET), polyimide (PI), and polyethylene naphthalate (PEN).

  The first electrode 56e is provided on one surface in the approximate center of the main block 56m. The first electrode 56e is made of a conductor layer, for example, a substantially circular metal printing layer. The first terminal 56c is made of a conductor layer, for example, a substantially rectangular metal layer. The first terminal 56c is provided on the surface of the tail block 56t on the side where the first electrode 56e is provided. The first electrode 56e and the first terminal 56c are electrically connected to each other via the first wiring 56w.

  The second electrode sheet 57 has a second insulating sheet 57s, a second electrode 57e, and a second terminal 57c as main components.

  As shown in FIG. 4, the second insulating sheet 57s is disposed closer to the seat cushion SC than the first electrode sheet 56, and is a resin-made insulating sheet similar to the first insulating sheet 56s. In the case of this embodiment, the second insulating sheet 57s includes a main block 57m having the same shape as the main block 56m of the first insulating sheet 56s, and the tail block 56t of the first insulating sheet 56s connected to the main block 57m and other than the tip portion. The tail block 57t has the same shape. The tip portion of the tail block 57t has a narrower width than other portions of the tail block 57t, and when the first insulating sheet 56s and the second insulating sheet 57s are overlapped, the tail block 56t of the first insulating sheet 56s. The tip portion of the second insulating sheet 57s and the tip portion of the tail block 57t of the second insulating sheet 57s do not overlap each other. Further, a through hole 57H is formed in the main block 57m at the same position as the through hole 50H of the switch sheet 50 in the same manner as the first insulating sheet 56s. As the material of the second insulating sheet 57s, a resin such as PET, PI, or PEN can be used similarly to the first insulating sheet 56s. The material of the second insulating sheet 57s is the same as the material of the first insulating sheet 56s. They can be the same or different.

  The second electrode 57e has the same configuration as that of the first electrode 56e, and is provided on one surface of the second insulating sheet 57s in the approximate center of the main block 57m. The position where the second electrode 57e is provided is a position that overlaps the first electrode 56e when the first electrode sheet 56 and the second electrode sheet 57 are overlapped. The second terminal 57c has the same configuration as that of the first terminal 56c, and is provided on the surface of the tail block 57t on the side where the second electrode 57e is provided. In addition, as described above, when the first insulating sheet 56s and the second insulating sheet 57s are overlapped, the tip portions of the respective insulating sheets do not overlap with each other, so the first terminal 56c and the second terminal 57c are not insulated from each other. The sheet 56s and the second insulating sheet 57s are not positioned and are exposed. The second electrode 57e and the second terminal 57c are electrically connected to each other through the second wiring 57w.

  The spacer 58 is disposed between the first electrode sheet 56 and the second electrode sheet 57 and is a flexible resin insulating sheet. The spacer 58 includes a main block 58m and a tail block 58t connected to the main block 58m. The main block 58m has the same outer shape as the main blocks 56m and 57m of the first insulating sheet 56s and the second insulating sheet 57s. Further, the main block 58m has an opening 58C formed in the center, and the through hole is located at the same position as the through hole 50H of the switch sheet 50 in the same manner as the first insulating sheet 56s and the second insulating sheet 57s. 58H is formed. The tail block 58t has a shape excluding the narrow tip portions of the tail blocks 56t and 57t of the first insulating sheet 56s and the second insulating sheet 57s.

  The opening 58C has a substantially circular shape, and has a diameter slightly smaller than the diameters of the first electrode 56e and the second electrode 57e. When the spacer 58 is overlapped with the first electrode sheet 56 and the second electrode sheet 57 and the spacer 58 is viewed in plan, the opening 58C is located inside the peripheral edges of the first electrode 56e and the second electrode 57e. It is formed to be located. Further, the spacer 58 is formed with a slit 58 b that connects the space in the opening 58 </ b> C and the space outside the switch sheet 50. The slit 58b serves as an air vent when the first electrode sheet 56, the spacer 58, and the second electrode sheet 57 are overlapped. When the spacer 58 is overlapped with the first electrode sheet 56 and the second electrode sheet 57 and the spacer 58 is viewed in plan, the opening 58C is positioned outside the peripheral edges of the first electrode 56e and the second electrode 57e. It may be formed.

  As the material of the spacer 58, a resin such as PET, PI, or PEN can be used as in the first insulating sheet 56s and the second insulating sheet 57s. The material of the spacer 58 may be the same as or different from the material of the first insulating sheet 56s or the second insulating sheet 57s. Further, an adhesive (not shown) for bonding the first electrode sheet 56 and the second electrode sheet 57 is applied to both surfaces of the spacer 58.

  With the first electrode sheet 56, the spacer 58, and the second electrode sheet 57 adhered in this order, the first electrode 56e, the first wiring 56w, and the second electrode sheet 57 of the first electrode sheet 56 are attached. The second electrode 57e and the second wiring 57w are located between the first insulating sheet 56s and the second insulating sheet 57s. Then, the first electrode 56e and the second electrode 57e are opposed to each other with a predetermined interval through the opening 58C to constitute a switch SW that is a pressure sensitive element. In addition, in a state where the first electrode sheet 56, the spacer 58, and the second electrode sheet 57 are overlapped, the respective through holes 56H, 57H, and 58H overlap each other to form the through hole 50H of the switch sheet 50.

  The signal cable 19 connected to a control device (not shown) is connected to the first terminal 56c and the second terminal 57c of the switch seat 50, respectively. The first terminal 56c and the second terminal 57c and the respective signal cables 19 are connected by conductive paste, soldering, or the like.

  The metal plate 60 is made of a metal plate material having a degree of flexibility that is difficult to bend compared to the switch sheet 50. The material of the metal plate 60 is not particularly limited, and examples thereof include copper and stainless steel. In the present embodiment, the metal plate 60 has substantially the same shape as the main block 50 m of the switch sheet 50.

  The metal plate 60 is formed with a through hole 60H at the same position as the through hole 50H of the switch sheet 50. When the switch sheet 50 and the metal plate 60 are stacked, the through hole 50H of the switch sheet 50 The through holes 60H of the metal plate 60 overlap each other. FIG. 5 is a front view of the load detection sensor 5A in a state where the switch sheet 50 and the metal plate 60 are overlapped with each other as described above. As shown in FIGS. 4 and 5, the metal plate 60 has a plurality of slits 60 </ b> S. Each slit 60 </ b> S is formed in a region overlapping the opening 58 </ b> C except for the center of the opening 58 </ b> C of the spacer 58 when the switch sheet 50 and the metal plate 60 are overlapped. In the present embodiment, the slits 60S are formed at symmetrical positions with respect to the center of the opening 58C, and the plurality of slits 60S are formed so as to spread radially from the center of the opening 58C. In the present embodiment, each slit 60 </ b> S extends to a region that does not overlap the opening 58 </ b> C of the spacer 58. That is, it can be understood that each of the plurality of slits 60S is formed from the inside to the outside of the edge of the opening 58C of the spacer 58. In the present embodiment, the width of each slit 60S is reduced toward the center of the opening 58C.

  When the metal plate 60 having such a shape is overlaid on the switch seat 50, the metal plate 60 covers the switch SW of the switch seat 50 via the adhesive layer 70 so that the switch cushion 50 on the seat cushion side is covered. Affixed to the surface.

  The adhesive layer 70 is a layered member that bonds the switch sheet 50 and the metal plate 60 as described above. In the present embodiment, the adhesive layer 70 has the same size and the same size as the metal plate 60. Therefore, in the adhesive layer 70, through holes 70H similar to the respective through holes 60H of the metal plate 60 are formed, and further slits 70S similar to the respective slits 60S of the metal plate 60 are formed. The material of the adhesive layer 70 may be any material as long as the switch sheet 50 and the metal plate 60 can be bonded together. For example, a thermoplastic resin, a thermosetting resin, a photo-curing resin, or the like can be given. It is done. The adhesive layer 70 may be a double-sided tape in which an adhesive layer is formed on both surfaces of a substrate such as PET or nonwoven fabric. In this case, the through hole 70H and the slit 70S are easily formed, which is preferable. Here, the glass transition point Tg of the adhesive layer 70 is preferably 85 ° C. or higher. Since the glass transition point Tg is 85 ° C. or higher, it is difficult to flow even in an environment where the temperature is high, such as in a car under hot weather, so that erroneous detection of seating due to the flow of the adhesive layer 70 can be suppressed. .

  As shown in FIG. 2, in the load detection sensor 5A having the above configuration, a part of the switch sheet 50 is disposed on the mounting portion 21 of the support plate 2A. Specifically, the main block 50m of the switch seat 50 having the switch SW is positioned on the main block placement portion 21m of the support plate 2A, and the tail block 50t of the switch seat 50 is the tail block placement portion 21t of the support plate 2A. Located on the top. Thus, the switch SW that is a pressure-sensitive element is placed on the support plate 2A. Further, the first terminal 56c and the second terminal 57c provided in the tail block 50t are in a state of protruding from the tail block mounting portion 21t. Accordingly, the first terminal 56c and the second terminal 57c are located in a region that does not overlap the support plate 2A. Then, each signal cable 19 connected to the first terminal 56c and the second terminal 57c of the switch seat 50 is led out from the support plate 2A.

  Thus, in the state where the load detection sensor 5A is disposed on the support plate 2A, the end of the tail block 50t of the switch seat 50 including the first terminal 56c and the second terminal 57c to which the signal cable 19 is connected, and The end portion of the tail block mounting portion 21t of the support plate 2A is covered with a protective resin 18 as shown in FIG. That is, when the part including the first terminal 56c and the second terminal 57c in the load detection sensor 5A is viewed in cross section, the protective resin 18 covers the outer periphery of this part. In FIG. 2, the protective resin 18 covers the first terminal 56c and the second terminal 57c and is away from the support plate 2A. However, FIG. 2 is an exploded view and does not show the state of assembly. The protective resin 18 is shown separated from the support plate 2A. FIG. 6 is a view showing the state of the protective resin 18, and specifically, is a cross-sectional view when the end portion of the tail block mounting portion 21t is viewed along the surface direction. As shown in FIGS. 1 and 6, the protective resin 18 includes a portion including the first terminal 56c and the second terminal 57c in the load detection sensor 5A, and the main block placement portion 21m side in the tail block placement portion 21t. The opposite end is covered. In other words, when the position where the protective resin 18 is fixed to the support plate 2A is viewed in cross section, the protective resin 18 covers the outer periphery of the support plate 2A and the load detection sensor 5A that are stacked on each other. Thus, the protective resin 18 is fixed to the tail block placement portion 21t of the support plate 2A by its own adhesive force. Further, since the protective resin 18 covers the first terminal 56c and the second terminal 57c, the signal cables 19 are prevented from being disconnected from the first terminal 56c and the second terminal 57c, and the first terminal 56c. The second terminal 57c is suppressed from being short-circuited by conductive dust or the like.

  The protective resin 18 is made of, for example, a polyamide resin, a polyimide resin, an olefin resin, a urethane resin, an acrylic resin, or the like, or a resin such as a photo-curing resin.

  Further, as described above, in the state where the upper case 4A covers the load detection sensor 5A placed on the support plate 2A and the respective hook pieces 47 are fitted in the respective case stop openings 24, the pressing portions 46 are The tip is in contact with a region overlapping the center of the opening 58C of the spacer 58 in the metal plate 60 of the load detection sensor 5A. Since the slit 60S is not formed in the region of the metal plate 60 that overlaps the center of the opening 58C of the spacer 58 as described above, the tip of the pressing portion 46 contacts the metal plate 60 without overlapping the slit 60S. Can do. Further, in this state, each rib 49 is inserted through the corresponding through hole 60H of the metal plate 60, the through hole 50H of the switch sheet 50, and the through hole 20H of the support plate 2A. Therefore, even when the support plate 2A and the first insulating sheet 56s are not bonded, the relative movement between the switch SW of the load detection sensor 5A and the pressing portion 46 of the upper case 4A is restricted. That is, the rib 49 can be understood as a movement regulating member that regulates relative movement between the switch sheet 50 and the support plate 2A in the surface direction of the support plate 2A.

  Such a load detection sensor unit 1A is attached to the S spring 100 as described above. As described above, this state is shown in a sectional view in FIG. As shown in FIG. 7, the hook portion 22 of the support plate 2A is placed on the two S springs 100 that face each other out of the plurality of S springs 100 that are stretched side by side in the opening 151 of the seat frame 150 via the buffer member 3A. Each of them can be fixed and the load detection sensor unit 1A can be attached to the seat. Further, as shown in FIG. 8, in one S spring 100 among a plurality of S springs 100 arranged and stretched in parallel with the opening 151 of the frame 150, the hook portion 22 of the support plate 2A is provided at a portion facing each other in the buffer member 3A. The load detection sensor unit 1A may be attached to the seat.

  Next, detection of seating by the load detection sensor unit 1A of the present embodiment will be described.

  FIG. 9 is a diagram illustrating an on state of the load detection sensor 5A. When a person sits on the seat device, the lower surface of the seat cushion SC moves downward, and the lower surface of the seat cushion SC contacts the upper surface 45S of the upper case 4A and presses the upper surface 45S. When the lower surface of the seat cushion SC further moves downward, as shown in FIG. 9, the tip of the pressing portion 46 presses the metal plate 60, and the metal plate 60 bends. At this time, since the plurality of slits 60S are formed in the metal plate 60, the metal plate 60 is easily bent as compared with the case where the slit 60S is not formed. For this reason, even if the thickness of the metal plate 60 is large, the metal plate 60 can bend appropriately. Due to the bending of the metal plate 60, the main block 57m of the second insulating sheet 57s is also bent. For this reason, the second electrode 57e contacts the first electrode 56e, and the switch SW of the load detection sensor 5A is turned on. Then, seating is detected by a vehicle control unit (not shown) connected to the signal cable 19. At this time, in this embodiment, the support plate side surface of the main block 56m of the first insulating sheet 56s is not bonded to the support plate 2A, so that at least the peripheral portion of the switch SW follows the way the metal plate 60 bends. The switch SW can be easily turned on.

  As described above, the load detection sensor 5A of the present embodiment includes the first electrode 56e and the second electrode 57e which are a pair of electrodes facing each other with a predetermined interval through the opening 58C provided in the spacer 58. And a metal plate 60 that covers at least a part of the second electrode 57e, which is one of the pair of electrodes, from the side opposite to the spacer 58. In the metal plate 60, a plurality of slits 60S are formed in a region overlapping the opening 58C except for the center of the opening 58C.

  According to such a load detection sensor 5A, when the metal plate 60 is pressed, the second electrode 57e bends, the first electrode 56e and the second electrode 57e come into contact with each other, and the switch is turned on. By the way, the flexibility of the metal does not change so much even when the temperature changes. Therefore, even when the environmental temperature around the load detection sensor 5A changes, the bending method of the metal plate 60 does not change so much. Therefore, according to the load detection sensor 5A, erroneous detection of the load can be suppressed even when the environmental temperature changes.

  Further, since the plurality of slits 60S are formed in the metal plate 60, the strength of elasticity of the metal plate 60 is adjusted by adjusting the size and number of the slits 60S without reducing the thickness of the metal plate 60. be able to. Therefore, since it is not necessary to make the metal plate thin, it is possible to prevent the metal plate 60 from being pressed. In addition, the slit 60 </ b> S is not formed in a region overlapping the center of the opening 58 </ b> C of the spacer 58 in the metal plate 60. The position of the metal plate 60 that overlaps the center of the opening 58C is the position that is most bent when the load is detected, and the second electrode 57e can be appropriately pressed at this position. For this reason, even if the load detection sensor 5A is downsized and the opening 58C of the spacer 58 is made small, the metal plate 60 can be flexed appropriately while suppressing the occurrence of the pushing rod, and the load Can be detected.

  In the load detection sensor 5 </ b> A of the present embodiment, each of the plurality of slits 60 </ b> S is formed at a symmetrical position with respect to the center of the opening 58 </ b> C of the spacer 58. Therefore, when the metal plate 60 is pressed, the bending method of the metal plate 60 can be made symmetric with respect to the center of the opening 58C. Therefore, it is possible to suppress a decrease in load detection accuracy due to a biased way of bending the second electrode 57e.

  In the load detection sensor 5A of the present embodiment, the plurality of slits 60S are formed so as to spread radially from the center of the opening 58C of the spacer 58. For this reason, the density of the metal located on the center side of the opening 58C of the spacer 58 in the metal plate 60 is smaller than the density of the metal located on the outer peripheral side of the opening 58C, and the metal plate 60 is more easily bent toward the center side of the opening 58C. can do. Further, stress tends to concentrate on a portion of the metal plate 60 located near the edge of the opening 58C of the spacer 58. However, as described above, the metal density increases on the outer peripheral side of the opening 58C. It is possible to further suppress the occurrence of pushing creases.

  In the load detection sensor 5 </ b> A of the present embodiment, each of the plurality of slits 60 </ b> S extends to a region that does not overlap the opening 58 </ b> C of the spacer 58. For this reason, it becomes easy to bend appropriately from the position where the metal plate 60 overlaps the opening edge of the opening 58C. Therefore, the load can be detected more appropriately.

  The load detection sensor unit 1A of the present embodiment is disposed under the seat cushion SC, and includes a load detection sensor 5A and an upper case 4A that is a pressing member. As described above, the load detection sensor 5A includes the first electrode 56e and the second electrode 57e which are a pair of electrodes facing each other with a predetermined interval through the opening 58C provided in the spacer 58, and the pair of electrodes. A metal plate 60 that covers at least a part of the second electrode 57e, which is one of the electrodes, from the side opposite to the spacer 58, and the metal plate 60 includes a plurality of regions in a region overlapping the opening 58C except for the center of the opening 58C. The slit is formed. The upper case 4A has an upper surface 45S that is a pressure receiving surface pressed against the seat cushion SC and a pressing portion 46 that is harder than the seat cushion SC and presses a position overlapping the center of the opening 58C in the metal plate 60.

  In such a load detection sensor unit 1A, the upper surface 45S of the upper case 4A receives a pressing force from the seat cushion SC, and the pressing portion 46 presses the metal plate 60 by the pressing force. Therefore, the metal plate 60 can be bent more appropriately by the upper case 4A, and the load can be detected more appropriately.

  Further, the load detection sensor unit 1A of the present embodiment presses a position overlapping the load detection sensor 5A and the upper surface 45S that is a pressure receiving surface that receives a load and the center of the opening 58C in the metal plate 60, and the metal plate 60. And an upper case 4A that is a pressing member having a pressing portion 46 having a contact area smaller than that of the upper surface 45S. Therefore, the load received by the upper surface 45 is transmitted to the pressing portion 46 whose contact area with the metal plate 60 is smaller than the area of the upper surface 45S, so that the load received in a wide area can be concentrated on the pressing portion 46. Therefore, the metal plate 60 can be bent more appropriately, and the load can be detected more appropriately.

  In the load detection sensor unit 1A of the present embodiment, the switch SW and the sheet-like load detection sensor 5A having the first terminal 56c and the second terminal 57c electrically connected to the switch SW and the switch SW are mounted. Support plate 2A, and a protective resin 18 covering the first terminal 56c and the second terminal 57c. The first terminal 56c and the second terminal 57c are located in a region that does not overlap the support plate 2A, and the protective resin 18 is fixed to the support plate 2A.

  By covering the first terminal 56c and the second terminal 57c with the protective resin, the connection structure between the first terminal 56c and the second terminal 57c and the signal cable 19 is protected, and the first terminal 56c and the second terminal 57c are protected. Dust and the like are prevented from adhering to the surface. Further, since the protective resin 18 is fixed to the support plate 2A on which a part of the load detection sensor 5A is placed, the protective resin 18 can be prevented from moving relative to the support plate 2A due to vibration or the like. Therefore, it is possible to suppress the partial bending and stretching of the load detection sensor 5A due to the movement of the protective resin 18. For this reason, even in an environment where vibration is applied, disconnection or the like due to bending or stretching of the load detection sensor 5A can be suppressed, and the durability is excellent.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. In the description of the present embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted unless specifically described.

  FIG. 10 is an exploded view showing the configuration of the load detection sensor unit of the present embodiment, and FIG. 11 is a cross-sectional view showing a state in which the load detection sensor unit is attached to the S spring of the seat device. FIG. 11 is a cross-sectional view of the load detection sensor unit on a surface along the left-right direction of the seat device. As shown in FIGS. 10 and 11, the load detection sensor unit 1B of the present embodiment includes a support plate 2B, a lower case 8B, an upper case 4B, and a load detection sensor 5B as main components.

  The support plate 2 </ b> B includes a placement portion 21 and a pair of hook portions 22 connected to the placement portion 21. In the present embodiment, the lower case 8B is placed on the placement portion 21, and the upper surface of the placement portion 21 is a placement surface 21S on which the lower case 8B is placed. The mounting portion 21 is formed with a plurality of case stop openings 24. The support plate 2B is formed by molding a metal plate, for example, like the support plate 2A of the first embodiment. In this case, the plate thickness is set to 0.8 mm, for example.

  The pair of hook portions 22 are provided at positions facing each other across the placement portion 21, and a pair of adjacent S springs among a plurality of S springs 100 stretched side by side in the opening of the frame in the vehicle seat device. Each is fitted into the spring 100. In this embodiment, as shown in FIG. 11, each hook part 22 is directly engage | inserted by S spring, without a buffer member. Accordingly, each hook portion 22 is a locking portion that locks the support plate 2 </ b> B to the S spring 100. In the present embodiment, the pair of hook portions 22 are formed so as to be fitted in a pair of S springs 100 arranged in the lateral direction of the seat device and adjacent in the lateral direction. In addition, in the state where the pair of hook portions 22 are fitted in the pair of adjacent S springs 100 in this way, the mounting portion 21 is mounted on the plurality of S springs 100 as in the first embodiment. The placement portion 21 is disposed between the pair of S springs 100 when the plurality of S springs are viewed from above, which is located below the SC.

  As shown in FIGS. 10 and 11, the lower case 8 </ b> B has a connector part 81 connected to a vehicle control unit (not shown) and a switch accommodating part 82 connected to the connector part 81. The switch accommodating portion 82 has a bottom wall 87 and a frame wall 88, and an accommodating space CA for accommodating the load detection sensor 5B is formed by the bottom wall 87 and the frame wall 88. In the present embodiment, the frame wall 88 is subjected to a blanking process to suppress deformation during resin molding.

  A pair of fixing pins 83 and a pair of connection pins 84 are provided on the bottom wall 87 of the switch housing portion 82. The pair of fixing pins 83 are pins for fixing the load detection sensors 5B housed in the lower case 8B. In addition, the pair of connection pins 84 are electrically connected to the connector terminals of the connector portion 81 and are also electrically connected to the load detection sensor 5B, and electrically connect the connector terminals and the load detection sensor 5B. It is a pin for. In FIG. 10, the connector terminals of the connector part 81 are omitted.

  A pair of projecting pieces 85 are provided on the outer surface of the frame wall 88 of the switch housing portion 82. In the present embodiment, the pair of protruding pieces 85 are provided so as to be arranged in the lateral direction of the seat. In addition, a plurality of hook pieces 86 are provided at the lower end of the frame wall 88 so as to be fitted into the respective case stop openings 24 of the support plate 2B. The lower case 8B is fixed to the support plate 2B by the hook pieces 86 being fitted into the case stopping openings 24 of the support plate 2B, and the lower case 8B is placed on the mounting surface 21S of the support plate 2B as described above. Placed.

  The upper case 4B is a lid member that covers the accommodation space CA of the switch accommodation portion 82, and is a pressing member that presses the switch of the load detection sensor 5B by being pressed by the seat cushion SC as in the first embodiment. The upper case 4 </ b> B has a top wall 45 and a frame wall 48. A pair of arms 41 is provided at the lower end of the frame wall 48 of the upper case 4B. Each arm 41 is formed with an opening 42 into which a protruding piece 85 provided on the frame wall 88 of the switch accommodating portion 82 in the lower case 8B is fitted. The upper case 4B is locked to the lower case 8B by fitting the pair of protruding pieces 85 of the lower case 8B into the openings 42 of the pair of arms 41, respectively. Therefore, in a state where the upper case 4B is locked to the lower case 8B, the pair of arms 41 sandwich the lower case 8B from the lateral direction of the seat.

  The top wall 45 of the upper case 4B is provided with a pressing portion 46 that protrudes from the inner surface facing the bottom wall 87 of the switch housing portion 82 in the lower case 8B. In this embodiment, the pressing portion 46 has a curved surface with a convex tip, and the upper case 4B covers the lower case 8B, and the protruding piece 85 is fitted in each opening 42. It is in contact with the switch of the load detection sensor 5B. That is, the distal end of the pressing portion 46 is in contact with the switch of the load detection sensor 5B in a state where the upper case 4B is not pressed by the seat cushion SC as will be described later.

  The upper case 4B is made of a material harder than the seat cushion SC, as in the first embodiment. Therefore, the pressing part 46 which is a part of the upper case 4B is also made of a material harder than the seat cushion SC, and is made of, for example, the same material as the upper case 4A of the first embodiment.

  Thus, with the pressing portion 46 of the upper case 4B in contact with the load detection sensor 5B, the top wall 45 of the upper case 4B and the frame wall 88 of the lower case 8B are separated as shown in FIG. A gap GA is formed.

  In a state where the assembled load detection sensor unit 1B is attached to the pair of S springs 100, the upper surface 45S of the top wall 45 of the upper case 4B faces the lower surface of the seat cushion SC with a predetermined distance therebetween. . The upper surface 45S is planar. The upper surface 45S is a surface pressed by the seat cushion SC, and can be understood as a pressure receiving surface of the load detection sensor unit 1B. The area of the upper surface 45S is larger than the area of the portion of the pressing portion 46 that contacts the switch of the load detection sensor 5B.

  Next, the load detection sensor 5B housed in the switch housing portion 82 of the lower case 8B will be described.

  FIG. 12 is an exploded view showing the configuration of the load detection sensor 5B. 13 is a sectional view taken along line XX of the load detection sensor 5B shown in FIG. 12, and FIG. 14 is a sectional view taken along line YY of the load detection sensor 5B shown in FIG.

  As shown in FIGS. 12 to 14, the load detection sensor 5 </ b> B includes a first electrode sheet 51, a second electrode sheet 52, and a spacer 59 as main components.

  The first electrode sheet 51 includes an insulating substrate 51s that has little flexibility. Examples of the material of the substrate 51s include phenol resin and epoxy resin. A first electrode 51e and a first contact portion 51c are disposed on one surface F1 of the substrate 51s facing the second electrode sheet 52.

  The first electrode 51e is one electrode constituting the switch SW, and is, for example, a circular metal printing layer. The first contact portion 51c is formed by connecting a substantially rectangular contact area AR1 that is in contact with the second electrode sheet 52 and a non-contact area AR2 that is not in contact with the second electrode sheet 52 to each other.

  In the substrate 51s, the other surface F2 opposite to the one surface F1 is a lower surface of the load detection sensor 5B, and a resistor 51R is disposed on the other surface F2. The resistor 51R is a resistor for detecting disconnection, and in the present embodiment, the resistor 51R is configured by a chip resistor.

  The substrate 51s is formed with a plurality of through holes penetrating from one surface F1 to the other surface F2 of the substrate 51s. The first sheet through hole 51m, the second sheet through hole 51n, and a pair of fixing holes, respectively. A through hole 51H and a pair of pin through holes 51f are provided.

  The first sheet through hole 51m is a sheet through hole in which an opening is located in a region where the first electrode 51e is disposed on one surface F1 of the substrate 51s. A first conductive member CPA is provided in the first sheet through hole 51m, and via the first conductive member CPA, a wiring disposed on the other surface F2 of the substrate 51s, the first electrode 51e, Are electrically connected. As a result, the first conductive member CPA and the resistor 51R are electrically connected, and as a result, the first electrode 51e and the resistor 51R are electrically connected. The first conductive member CPA is provided on the inner peripheral surface of the first sheet through hole 51m, and an air hole SP surrounded by the first conductive member CPA is formed in the first sheet through hole 51m. It is formed.

  The second sheet through hole 51n is a sheet through hole in which an opening is located in a region where the first contact portion 51c is disposed on one surface F1 of the substrate 51s. In the present embodiment, the opening of the second sheet through hole 51n is positioned in the non-contact area AR2 of the first contact portion 51c.

  The second conductive member CPB is filled in the second sheet through hole 51n. Via this second conductive member CPB, the wiring arranged on the other surface F2 of the substrate 51s and the non-contact area AR2 of the first contact portion 51c are electrically connected, and on the other surface F2 of the substrate 51s. The second conductive member CPB is connected to the resistor 51R. Therefore, the resistor 51R and the first contact portion 51c are electrically connected. Since the first electrode 51e and the resistor 51R are electrically connected as described above, the first electrode 51e, the resistor 51R, and the first contact portion 51c are electrically connected in series in this order.

  The pair of fixing through holes 51H are through holes into which the pair of fixing pins 83 provided in the bottom wall 87 of the switch housing portion in the lower case 8B are respectively inserted. The diameters of the fixing through holes 51H are approximately the same as the outer diameters of the pair of fixing pins 83.

  The pair of pin through holes 51f are through holes into which the pair of connection pins 84 provided in the lower case 8B are respectively inserted. Each pin through hole 51f is provided with a terminal 51t which is a terminal portion of an electric circuit in the load detection sensor 5B. One terminal 51t of the pair of terminals 51t is electrically connected to a contact point between the first electrode 51e and the resistor 51R, and the other terminal 51t is electrically connected to a contact point between the resistor 51R and the first contact part 51c. Is done. Each terminal 51t is provided along the inner peripheral surface of each pin through hole 51f, and the inner diameter of the space surrounded by each terminal 51t is approximately the same as the outer diameter of the connection pin 84. The The connection pin 84 is inserted into the pin through hole 51f, whereby the terminal 51t and the connection pin 84 are electrically connected.

  The 2nd electrode sheet 52 consists of metal plates 61, and has the 2nd electrode 52e and the 2nd contact part 52c as the main composition.

  The metal plate 61 is made of a thin metal having flexibility. In this embodiment, the metal plate 61 has a vertical width slightly shorter than the vertical width of the substrate 51s, and a thin shape having a horizontal width substantially equal to the horizontal width of the substrate 51s. It is said. The material of the metal plate 61 is not particularly limited as long as it is a conductive metal, and examples thereof include copper and stainless steel.

  The metal plate 61 is formed with a pair of fixing through holes 61H penetrating the metal plate 61. These fixing through holes 61H are through holes through which a pair of fixing pins 83 provided on the bottom wall of the switch housing portion in the lower case 8B are inserted, and a pair of holes formed in the substrate 51s of the first electrode sheet 51. It is the same shape and size as the fixing through hole 51H. Further, the arrangement site of the second electrode 52e and the second contact portion 52c with respect to the fixing through hole 61H and the arrangement site of the first electrode 51e and the first contact portion 51c with respect to the fixing through hole 51H in the first electrode sheet 51 are described. When the first electrode sheet 51 and the metal plate 61 are overlapped with each other, the pair of fixing through holes 51H and the pair of fixing through holes 61H overlap each other.

  The second electrode 52e is the other electrode constituting the switch SW. In the present embodiment, the second electrode 52e is a portion facing the first electrode 51e through the spacer 59 in the metal plate 61. That is, a part of the metal plate 61 also serves as the second electrode 52e. Therefore, as shown in FIGS. 10 and 11, the second electrode 52e located on the seat cushion SC side of the first electrode 51e and the second electrode 52e is covered with the metal plate 61 from the seat cushion side, as described above. It can be understood that it is integrated with the metal plate 61. For example, a metal layer made of the same material as or different from that of the metal plate 61 may be disposed as a second electrode 52e in a portion of the metal plate 61 that faces the first electrode 51e via the spacer 59.

  The metal plate 61 is formed with a plurality of slits 61S. Each slit 61S has the same shape as the slit 60S of the first embodiment, and is formed in a region overlapping the second electrode 52e except for the center of the second electrode 52e. In the present embodiment, the plurality of slits 61S are formed at symmetrical positions with respect to the center of the second electrode 52e, and are formed so as to spread radially from the center of the second electrode 52e. In the present embodiment, the plurality of slits 61S are formed to extend to a region that does not overlap the second electrode 52e. That is, it can be understood that the plurality of slits 61S are formed from the inner side to the outer side of the edge of the second electrode 52e.

  The 2nd contact part 52c is one member which comprises the connection maintenance part AP, and is formed as a leaf | plate spring in this embodiment. That is, the metal plate 61 is provided with a pair of notches 61d (FIG. 10) extending from one end of the metal plate 61 toward the other end side with a predetermined interval, and a portion sandwiched between the notches 61d. The second contact portion 52c is used. Further, the second contact portion 52c is bent toward the first electrode sheet 51 so that the second contact portion 52c is inclined with respect to the plate surface of the metal plate 61, whereby the second contact portion 52c is It is formed as a leaf spring. In this way, a portion of the metal plate 61 that is different from the portion that is the second electrode 52e is the second contact portion 52c. The position at which the second contact portion 52c is formed is a position that overlaps the contact area AR1 of the first contact portion 51c when the first electrode sheet 51 and the second electrode sheet 52 are overlapped. The shape of the leaf spring formed as the second contact portion 52c may be, for example, a trapezoid whose base width is larger than the width of the open end, and various shapes other than a rectangle and a trapezoid are applicable. is there. Further, as the second contact portion 52 c, a metal layer made of the same material as or different from the metal plate 61 may be disposed on the first electrode sheet 51 side in the metal plate 61.

  The spacer 59 is a thin insulating member sandwiched between the first electrode sheet 51 and the second electrode sheet 52. In the present embodiment, the spacer 59 has substantially the same shape as that obtained by removing the second contact portion 52c from the metal plate 61. The same size. Examples of the material of the spacer 59 include resins such as PET, PI, and PEN.

  The spacer 59 has an opening 59C. The opening 59C is between the first electrode 51e disposed on the substrate 51s and the second electrode 52e of the metal plate 61 opposed to the first electrode 51e, and the first electrode 51e and the first electrode in the vertical direction. It is formed at a position overlapping the two electrodes 52e. The size of the opening 59C is slightly smaller than the size of the first electrode 51e.

  Further, the spacer 59 is formed with a notch 59d. The notch 59d is between the first contact portion 51c disposed on the substrate 51s and the second contact portion 52c of the metal plate 61 facing the first contact portion 51c, and is the first in the vertical direction. It is formed at a position overlapping with the contact part 51c and the second contact part 52c. The size of the notch 59d is slightly larger than the size of the leaf spring formed as the second contact portion 52c in the metal plate 61.

  Further, the spacer 59 is formed with a pair of fixing through holes 59H penetrating the spacer 59. These fixing through holes 59H are through holes through which fixing pins 83 provided on the bottom wall of the switch housing portion in the lower case 8B are inserted, and the fixing through holes 51H formed in the substrate 51s of the first electrode sheet 51. The same shape and size. In addition, the positions of the openings 59C and the cutouts 59d with respect to the pair of fixing through holes 59H in the spacer 59, and the arrangement of the first electrodes 51e and the first contact portions 51c with respect to the pair of fixing through holes 51H in the first electrode sheet 51 are provided. The positional relationship is relatively the same as the part. Therefore, when the first electrode sheet 51, the spacer 59, and the second electrode sheet 52 are stacked, the pair of fixing through holes 51H of the first electrode sheet 51 and the pair of fixing through holes 61H of the second electrode sheet 52 The pair of fixing through holes 59H of the spacer 59 overlap each other, and the fixing through hole 51H, the fixing through hole 61H, and the fixing through hole 59H overlap each other.

  The first electrode sheet 51, the second electrode sheet 52, and the spacer 59 are overlapped to constitute the load detection sensor 5B. In the load detection sensor 5B, as shown in FIG. 13, the first electrode 51e and the second electrode 52e face each other with a predetermined interval through the opening 59C to form a switch SW. In a state where the first electrode 51e and the second electrode 52e are separated from each other, the distance between the first electrode 51e and the second electrode 52e is, for example, 0.1 mm. And the air hole SP in the through-hole formed in the 1st electrode 51e is connected to the opening 59C. Therefore, when the second electrode 52e is bent and contacts the first electrode 51e, unnecessary air can be discharged from the air hole SP to the outside of the load detection sensor 5B. As described above, the first sheet through hole 51m is only a hole for electrically connecting the first electrode 51e disposed on the one surface F1 of the substrate 51s and the circuit portion disposed on the other surface F2 side. It also serves as an exhaust hole for discharging the air in the opening 59C to the outside of the load detection sensor 5B.

  In addition, as described above, each slit 61S is formed in a region overlapping the second electrode 52e except for the center of the second electrode 52e, so that the first electrode sheet 51, the second electrode sheet 52, and the spacer 59 are overlapped. In this state, each slit 61S is formed in a region overlapping with the opening 59C except for the center of the opening 59C of the spacer 59. In the present embodiment, as described above, the plurality of slits 61S are formed at symmetrical positions with respect to the center of the second electrode 52e, and are formed so as to spread radially from the center of the second electrode 52e. Therefore, the plurality of slits 61S are formed at symmetrical positions with respect to the center of the opening 58C and are formed so as to spread radially from the center of the opening 58C. In the present embodiment, as described above, the plurality of slits 61S are formed so as to extend to a region that does not overlap the second electrode 52e, and thus the plurality of slits 61S are regions that do not overlap the opening 58C of the spacer 58. It is formed to extend to.

  Further, as described above, in the load detection sensor 5B, the second contact portion 52c of the second electrode sheet 52 is formed as a plate spring, and is plastically deformed with respect to the plate surface of the metal plate 61 so as to be always inclined. is there. For this reason, as shown in FIG. 14, the second contact portion 52 c passes through the notch 59 d of the spacer 59 and is connected to the contact area AR <b> 1 of the first contact portion 51 c of the first electrode sheet 51. Thus, the connection maintaining part AP is formed by the first contact part 51c and the second contact part 52c coming into contact with each other. In other words, the first contact portion 51c of the first electrode sheet 51 is one member constituting the connection maintaining portion AP that maintains electrical connection even when no external pressure is applied to the upper case 4B, and the second electrode The second contact part 52c of the sheet 52 is the other member constituting the connection maintaining part AP.

  In such a load detection sensor 5B, as shown in FIG. 10, the pair of fixing pins 83 in the lower case 8B are a pair of fixing through holes 51H in the first electrode sheet 51 and a pair of fixing through holes in the spacer 59. It is fixed to the lower case 8B by being inserted through the pair of fixing through holes 61H of 59H and the second electrode sheet 52 in order.

  In a state where the load detection sensor 5B is fixed to the lower case 8B, the pair of connection pins 84 are inserted into the pair of pin through holes 51f of the first electrode sheet 51, respectively. As a result, the terminals 51t provided in the pin through holes 51f are in contact with the corresponding connection pins 84 and are electrically connected to the connector terminals of the connector portion 81 of the lower case 8B via the connection pins 84. .

  Further, by attaching the upper case 4B, the tip of the pressing portion 46 contacts the opposite side of the second electrode 52e to the first electrode 51e side in the switch SW as described above. Specifically, the tip of the pressing portion 46 contacts the metal plate 61 at a position overlapping the center of the opening 59 </ b> C of the spacer 59 in the metal plate 61. This position is also a position overlapping the center of the second electrode 52e, and is a position where the plurality of slits 61S are not formed. In addition, this position is also a position surrounded by the plurality of slits 61S in the present embodiment. The area of the pressing portion 46 that contacts the second electrode 52e is smaller than the area of the second electrode 52e, and the area of the upper surface 45S that is the pressure receiving surface is larger than the area of the second electrode 52e. In this way, with the load detection sensor 5B fixed to the lower case 8B and the upper case 4B attached, the relative movement between the upper case 4B and the load detection sensor 5B in the surface direction of the metal plate 61 is restricted. . In this relative movement restriction, the pair of fixing pins 83 restricts the movement of the load detection sensor 5B relative to the lower case 8B, and the pair of arms 41 restricts the horizontal movement of the upper case 4B relative to the lower case 8B. It depends. Therefore, in the present embodiment, the pair of fixing pins 83 and the pair of arms 41 are provided with the first movement restricting member that restricts the relative movement between the upper case 4 </ b> B and the metal plate 61 in the surface direction of the metal plate 61. It is composed.

  FIG. 15 is a diagram showing an equivalent circuit of the load detection sensor 5B fixed to the lower case 8B. As shown in FIG. 15, between the pair of terminals 51t that are the circuit ends of the load detection sensor 5B, the switch SW including the first electrode 51e and the second electrode 52e, the first contact portion 51c, and the second contact portion. The connection maintaining unit AP consisting of 52c is connected. The switch SW is electrically connected between the pair of terminals 51t, and is connected to a connector terminal provided in the connector portion 81 of the lower case 8B via the pair of terminals 51t. Further, as described above, the resistor 51R is electrically connected to the first electrode 51e and the first contact portion 51c, and therefore the resistor 51R is electrically connected in parallel to the switch SW. Therefore, when the switch SW is turned on, the resistance value between the pair of terminals 51t is lower than when the switch SW is turned off.

  Next, detection of seating by the load detection sensor unit 1B of the present embodiment will be described.

  When a person sits on the seat device, the lower surface of the seat cushion SC moves downward due to the load of the person, and the lower surface of the seat cushion SC contacts the upper surface 45S of the upper case 4B. When the lower surface of the seat cushion SC moves further downward, the lower surface of the seat cushion SC presses the upper surface 45S of the upper case 4B. When the lower surface of the seat cushion SC further moves downward, the gap GA is formed between the upper case 4B and the lower case 8B as described above, so the upper case 4B is within the range of the gap GA. Move down.

  FIG. 16 is a diagram illustrating an on state of the load detection sensor 5B. Due to the downward movement of the upper case 4B, the tip of the pressing portion 46 presses the second electrode 52e, and as shown in FIG. 16, the second electrode 52e contacts the first electrode 51e, and the load detection sensor 5B The switch SW is turned on. That is, the second electrode 52e contacts the first electrode 51e due to the bending of the metal plate 61 caused by the pressing portion 46 pressing the metal plate 61. For this reason, the resistance value between the pair of terminals 51t becomes low, and the change in resistance is detected by the vehicle control unit (not shown) via the connection pin 84 and the connector terminal. Thus, seating is detected.

  At this time, as described above, the tip of the pressing portion 46 comes into contact with the position where the tip of the metal plate 61 overlaps the center of the opening 59C of the spacer 59, so the pressing portion 46 presses the metal plate 61 at the position. As described above, since the plurality of slits 61S are formed in the metal plate 61, the metal plate 61 is easily bent as compared with the case where the slit 61S is not formed. For this reason, even if the thickness of the metal plate 61 is large, the metal plate 61 can bend appropriately.

  In addition, as described above, the area of the upper surface 45S, which is the pressure receiving surface pressed against the seat cushion SC, is larger than the area of the portion that contacts the second electrode 52e, which is the tip of the pressing portion 46. Thus, the pressing force received in step 1 can be concentrated on the pressing portion 46, and the metal plate 61 can be bent more appropriately. In particular, in the present embodiment, since the tip of the pressing portion 46 has a convex curved shape, the pressing force is applied to the metal plate 61 at a higher density than when the tip of the pressing portion 46 is flat. The metal plate 61 can be bent more appropriately. Furthermore, since the area of the upper surface 45S is larger than the area of the second electrode 52e as described above, the seat cushion SC can transmit force to the upper surface 45S from other than directly above the second electrode 52e. For this reason, a pressing force can be more concentrated on the pressing part 46, and the metal plate 61 can be bent more appropriately.

  As described above, the load detection sensor 5B of the present embodiment is a pair of electrodes facing each other with a predetermined interval through the opening 59C provided in the spacer 59, like the load detection sensor 5A of the first embodiment. A first electrode 51e and a second electrode 52e, and a metal plate 61 that covers at least a part of the second electrode 52e, which is one of the pair of electrodes, from the side opposite to the spacer 59. In the metal plate 61, a plurality of slits 61S are formed in a region overlapping the opening 59C except for the center of the opening 59C.

  Therefore, according to the load detection sensor 5B of this embodiment, similarly to the load detection sensor 5A of the first embodiment, even when the environmental temperature changes, it is possible to suppress erroneous detection of the load. Even when the detection sensor 5B is miniaturized and the opening 59C of the spacer 59 is made small, the metal plate 61 can be appropriately bent while suppressing the occurrence of push rods, and the load can be detected appropriately. Can do.

  Moreover, the load detection sensor unit 1B of this embodiment is arrange | positioned under the seat cushion SC, and is provided with the load detection sensor 5B and the upper case 4B which is a press member. The upper case 4B includes an upper surface 45S that is a pressure receiving surface pressed against the seat cushion SC and a pressing portion 46 that is harder than the seat cushion SC and presses a position overlapping the center of the opening 59C of the spacer 59 in the metal plate 61.

  Therefore, according to the load detection sensor unit 1B of the present embodiment, the metal plate 61 can be bent more appropriately by the upper case 4B in the same manner as the load detection sensor unit 1A of the first embodiment, and more appropriately. The load can be detected.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the description of the present embodiment, the same or equivalent components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted unless specifically described.

  FIG. 17 is a view showing the load detection sensor 5A of the present embodiment from the same viewpoint as FIG. As shown in FIG. 17, in the load detection sensor 5A of this embodiment, the shape of the plurality of slits 60S formed in the metal plate 60 is different from the plurality of slits 60S of the first embodiment. Specifically, each of the slits 60 </ b> S of the present embodiment has a plurality of horizontally long shapes that are parallel to each other, and is formed so as to cross the opening 58 </ b> C of the spacer 58. In the present embodiment, a plurality of slits 60S are provided on the tail block 50t side with respect to the center of the opening 58C of the spacer 58 and on the opposite side of the tail block 50t with respect to the center of the opening 58C of the spacer 58. Accordingly, the plurality of slits 60S are formed in a region overlapping the opening 58C except for the center of the opening 58C of the spacer 58. In the present embodiment, each slit 60S is formed at a symmetrical position with respect to the center of the opening 58C.

  The load detection sensor 5A is not particularly illustrated, but is the load detection sensor 5A in the load detection sensor unit 1A in the same manner as in the first embodiment.

  In the load detection sensor 5A of the present embodiment, the metal plate 60 tends to bend more easily in the direction perpendicular to the direction in which the parallel slits 60S extend than in the direction in which the parallel slits 60S extend. Therefore, the metal plate 60 repulsively exerts a force required to turn on the switch SW in the direction perpendicular to the direction in which the slits 60S extend, while the repulsive force of the metal plate 60 in the direction in which the mutually parallel slits 60S extend. The plate 60 can be restored. Accordingly, it is possible to further suppress the pressing of the metal plate 60.

  As mentioned above, although the said embodiment was demonstrated to the example about the load detection sensor and load detection sensor unit of this invention, this invention is not limited to the said embodiment.

  For example, in the above embodiment, the load detection sensors 5A and 5B are a part of the load detection sensor units 1A and 1B, but the load detection sensors 5A and 5B of the present invention may be incorporated in other units. good.

  Further, in the load detection sensor 5B of the second embodiment, the slits 61S are provided radially like the load detection sensor 5A of the first embodiment. However, also in the load detection sensor 5B of the second embodiment, a plurality of slits 61S may be formed in parallel to each other, similarly to the load detection sensor 5A of the third embodiment.

  Next, some modified examples of the load detection sensor 5A will be described. In describing the following modified examples, the same or equivalent components as those in the first embodiment and the third embodiment are denoted by the same reference numerals, and redundant description is omitted unless specifically described. .

  FIG. 18 is a diagram illustrating a first modification of the load detection sensor 5A. In the first embodiment, the plurality of slits 60S extend from the region that overlaps the opening 58C of the spacer 58 to the region that does not overlap, whereas in this modification, only the position where the plurality of slits 60S overlap the opening 58C of the spacer 58 is provided. Is formed. Although not particularly illustrated, in the load detection sensor 5 </ b> A of the third embodiment, a plurality of slits 60 </ b> S parallel to each other may be formed only at a position where the slit 58 </ b> C overlaps the opening 58 </ b> C of the spacer 58. In the first to third embodiments, at least one of the plurality of slits 60S and 61S extends to a region that does not overlap with the openings 58C and 59C, and the other slits 60S and 61S only overlap with the openings 58C and 59C. It is good also as what is formed. As described above, stress tends to concentrate on the portion of the metal plate 60 located near the edge of the opening 58C of the spacer 58. However, according to the present modification in which the plurality of slits 60S are formed only at positions where the slits 58S overlap the openings 58C of the spacer 58, the repulsive force of the metal plate 60 in the region where the stress is concentrated can be increased. In addition, the metal plate 60 can be restored by the amount of the small slit 60S. Accordingly, it is possible to further reduce the pushing rod.

FIG. 19 is a diagram illustrating a second modification of the load detection sensor 5A. In the load detection sensor 5A of the present modification, each slit 60S is divided into a plurality of slit portions 60S ₁ , a slit portion 60S ₂ and a slit portion 60S ₃ , and the load detection sensor 5A of the first embodiment. Different. Thus, by dividing the slit 60S formed along the radial direction of the opening 58C of the spacer 58, the region overlapping the opening 58C of the metal plate 60 becomes more natural flexure and suppresses extreme stress concentration. it can.

  FIG. 20 is a diagram illustrating a third modification of the load detection sensor 5A. The load detection sensor 5A of the present modification is different from the load detection sensor 5A of the third embodiment in that the switch SW and a part of the opening 58C are not covered by the metal plate 60. In this case, the metal plate 60 can be made small, and the amount of metal used for the metal plate 60 can be reduced. Therefore, the load detection sensor can be made inexpensive.

  In the embodiment and the modification, the plurality of slits 60S and 61S are formed at symmetrical positions with respect to the centers of the openings 58C and 59C of the spacers 58 and 59, respectively. However, in the present invention, at least two of the plurality of slits 60S and 61S are formed at symmetrical positions with respect to the centers of the openings 58C and 59C of the spacers 58 and 59, and some of the slits 60S and 61S are formed in the spacers 58 and 61S. It does not have to be formed at a symmetrical position with respect to the centers of the openings 58C and 59C of the 59. The slits 60S and 61S may not be formed at symmetrical positions with respect to the centers of the openings 58C and 59C of the spacers 58 and 59.

  Further, in the third embodiment or the third modified example, a slit non-parallel to the other slit 60S may be formed. For example, in the third embodiment and the third modified example, four mutually parallel slits 60S are formed, but one or two of the slits 60S may be non-parallel.

  Further, for example, in the first embodiment, the load detection sensor 5A is placed directly on the support plate 2A. However, similarly to the third embodiment, a lower case is arranged on the support plate 2A, and the lower portion The main block 50m of the load detection sensor 5A may be arranged on the case, and the tail block 50t may be led out from the lower case. In the third embodiment, the lower case 8B may be omitted, and the load detection sensor 5B may be directly disposed on the support plate 2B.

  In addition to the contents shown in the above-described embodiments and modifications, the respective components in the load detection sensor unit are appropriately combined, omitted, changed, or added with a well-known technique within a range not departing from the purpose of the present application. Can do.

  In addition, the load detection sensor and the load detection sensor unit of the present invention can be used for purposes other than detection of seating as long as they are used for detecting a load. For example, it can be used as an electronic component such as a push button device. In the above embodiment, load detection sensor units 1A and 1B are attached to a plurality of S springs arranged side by side in the opening of the frame of the seat, and the load due to the seating of a person is detected by the load detection sensor units 1A and 1B. did. However, in the case where the load detection sensor unit of the present invention is disposed under the seat cushion, not only the above embodiment but also other forms can be employed. For example, the form which attaches a load detection sensor unit to several springs arranged and stretched under the seat cushion of a care bed is mentioned. Even if it is such a form, it can show whether a person exists in the bed for care using a load detection sensor unit. An elastic member may be used as the seat cushion as the seat cushion. As the elastic member, any material may be used as long as it has an elastic force and can transmit the load from the detection object to the load detection sensor unit. Examples of the elastic member include urethane, silicon, And ethylene propylene.

  As described above, according to the present invention, it is possible to provide a load detection sensor and a load detection sensor unit that can be downsized while appropriately detecting a load, and can be used in technical fields such as a seat device and a care bed. Can do.

1A, 1B ... Load detection sensor units 2A, 2B ... Support plate 3A ... Buffer members 4A, 4B ... Upper case 5A, 5B ... Load detection sensor 18 ... Protective resin 21 ... -Placement part 22 ... Hook part 51, 56 ... 1st electrode sheet 52, 57 ... 2nd electrode sheet 58.59 ... Spacer 58C, 59C ... Opening 60, 61 ... Metal plates 60S, 61S ... Slit SC ... Seat cushion SW ... Switch

Claims (7)

A pair of electrodes facing each other at a predetermined interval through an opening provided in the spacer;
A metal plate covering at least a part of one of the pair of electrodes from the side opposite to the spacer;
With
The load detection sensor according to claim 1, wherein a plurality of slits are formed in the metal plate in a region overlapping the opening except for the center of the opening. The load detection sensor according to claim 1, wherein at least two of the plurality of slits are formed at symmetrical positions with respect to the center. The load detection sensor according to claim 1, wherein the plurality of slits are formed so as to spread radially from the center. The load detection sensor according to claim 1, wherein at least two of the plurality of slits are formed in parallel to each other. 5. The load detection sensor according to claim 1, wherein at least one of the plurality of slits extends to a region that does not overlap with the opening. The load detection sensor according to any one of claims 1 to 5,
A pressure receiving surface that receives a load and a pressing member that presses a position overlapping the center of the opening in the metal plate and has a pressing portion whose contact area with the metal plate is smaller than the pressure receiving surface;
A load detection sensor unit comprising: The pressure receiving surface receives a load due to a pressing force from a seat cushion,
The load detection sensor unit according to claim 6, wherein the pressing portion is harder than the seat cushion.

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