WO2018101440A1

WO2018101440A1 - Load detection sensor and load detection sensor unit

Info

Publication number: WO2018101440A1
Application number: PCT/JP2017/043176
Authority: WO
Inventors: 直博菊川
Original assignee: 株式会社フジクラ
Priority date: 2016-12-01
Filing date: 2017-11-30
Publication date: 2018-06-07
Also published as: JP2018092771A; JP6684696B2

Abstract

This load detection sensor (5) is provided with: a pressure-sensitive sheet (50) having a first insulation sheet and a second insulation sheet which face each other, a spacer disposed between the first insulation sheet and the second insulation sheet, and a pressure-sensitive element; a chip-type electronic component (80) electrically connected to the pressure-sensitive element and disposed on an exposed part (EP1) of the surface on the spacer-facing side of the first insulation sheet, the exposed part (EP1) being exposed to the spacer and the second insulation sheet; a first protection resin (18A) disposed on the exposed part (EP1), and covering at least a portion of a side of the chip-type electronic component (80); and a second protection resin (18B) that covers the chip-type electronic component (80) and the first protection resin (18A), and also covers at least a portion of the exposed part (EP1) and at least a portion of a surface of the second insulation sheet, said surface being on the reverse side of the surface on the spacer-facing side of the second insulation sheet.

Description

Load detection sensor and load detection sensor unit

The present invention relates to a load detection sensor and a load detection sensor unit, and is suitable, for example, when used in an environment where vibration is applied.

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

As a load detection sensor, one having a first sheet and a second sheet and a spacer interposed between the first sheet and the second sheet is disclosed (Patent Document 1 below). Circuits are formed on the main surface of the first sheet and electronic components are mounted, and openings are formed in the spacer and the second sheet that are located above the region where the electronic components are mounted.

By stacking the first sheet, the spacer, and the second sheet in order, an electronic component mounted on the circuit on the main surface of the first sheet is placed inside the opening of the spacer and the second sheet. positioned. In addition, a reinforcing resin member that circumscribes the electronic component is provided so as to cover the circuit located inside the opening, and the electric contact between the electronic component and the circuit is ensured by the reinforcing resin member. In addition, the fixed part of the electronic component is reinforced.

JP 2011-009340 A

However, in the case of the load detection sensor of Patent Document 1, even if the first sheet, the spacer, and the second sheet are sequentially stacked, the first sheet is formed in the opening of the spacer and the second sheet. Therefore, for example, when stress is applied in the stacking direction, the first sheet on the inner side of the opening of the spacer and the second sheet is easily bent, and disconnection between the electronic component and the circuit fixed by the reinforcing resin member by the bending. There is a concern that this will occur. For this reason, the load detection sensor which is more excellent in durability is calculated | required.

Therefore, an object of the present invention is to provide a load detection sensor and a load detection sensor unit that are excellent in durability.

In order to solve the above problems, a load detection sensor according to the present invention includes a first insulating sheet and a second insulating sheet facing each other, a spacer disposed between the first insulating sheet and the second insulating sheet, and a pressure sensitive element. And a pressure-sensitive sheet, and an exposed portion exposed from the spacer and the second insulating sheet in a surface of the first insulating sheet facing the spacer, and electrically connected to the pressure-sensitive element A chip-type electronic component, a first protective resin provided at the exposed portion and covering at least a part of the side of the chip-type electronic component, and covering the chip-type electronic component and the first protective resin And a second protective resin that covers at least a part of the exposed portion and at least a part of a surface of the second insulating sheet opposite to the surface facing the spacer. And features.

In such a load detection sensor, the chip-type electronic component and the first protective resin are covered with the second protective resin, and at least a part of the outer surface of the second insulating sheet and the exposed surface of the first insulating sheet is covered. ing. For this reason, even if stress is applied from the outside, the first insulating sheet, the spacer, and the second insulating sheet constituting the pressure-sensitive sheet can be made difficult to peel off. The chip-type electronic component is fixed to the exposed portion of the first insulating sheet with the first protective resin, and is further covered with the second protective resin. For this reason, even if stress is applied from the outside, the electrical connection relationship between the chip-type electronic component and the pressure-sensitive element can be easily maintained. Thus, the durability of the load detection sensor can be improved.

The second protective resin wraps around the outer periphery of the first insulating sheet passing through the chip-type electronic component in a direction perpendicular to the surface of the first insulating sheet facing the spacer. It is preferable.

In such a case, since the outer periphery of the first insulating sheet passing through the chip type electronic component is wrapped, it is possible to suppress dust and the like from adhering to the chip type electronic component. Therefore, it is possible to reduce the size while further improving the durability.

In addition, it is preferable that the second protective resin wraps a part of the outer periphery of the pressure sensitive sheet.

In this case, the first insulating sheet, the spacer, and the second insulating sheet constituting the pressure-sensitive sheet can be made more difficult to peel off.

The pressure-sensitive sheet is provided in a portion of the exposed portion different from the portion where the chip-type electronic component is provided, and has a terminal electrically connected to the pressure-sensitive element, and the second protection The resin preferably covers the terminal.

In this case, since the terminal is also covered with the second protective resin, the connection structure between the terminal and the signal cable connected to the terminal is protected, and the adhesion of dust or the like to the terminal is suppressed. Furthermore, it is not necessary to provide a protective member for protecting the terminal separately. Therefore, it is possible to reduce the size while further improving the durability.

Further, it is preferable that the second protective resin also covers a side surface of the first insulating sheet in the exposed portion.

In this case, the entry of dust and the like from the side surface of the exposed portion of the first insulating sheet is suppressed, and the adhesion of dust and the like to the chip-type electronic component is suppressed. Therefore, it is possible to reduce the size while further improving the durability.

The first protective resin is preferably harder than the second protective resin.

In this case, since the stress applied from the outside can be absorbed by the second protective resin while fixing the chip-type electronic component to the exposed portion with the first protective resin, the durability can be further improved. .

The first protective resin is preferably a thermosetting resin or a photo-curable resin, and the second protective resin is preferably a thermoplastic resin.

Even in this case, since the stress applied from the outside can be absorbed by the second protective resin while fixing the chip-type electronic component to the exposed portion with the first protective resin, the durability can be further improved. Can do. In addition, when the first protective resin is a thermosetting resin, it is possible to suppress the first protective resin from being deformed by heat even under high temperature conditions.

In addition, a load detection sensor unit of the present invention includes any one of the load detection sensors described above and a support plate on which the pressure sensitive sheet is placed, and the second protective resin is combined with a part of the pressure sensitive sheet. The part is covered so as to surround the support plate on which the part is placed.

In such a load detection sensor unit, since the pressure-sensitive sheet can be fixed to the support plate by the second protective resin, the movement of the pressure-sensitive sheet relative to the support plate can be suppressed even if vibration or the like occurs. Also, compared to the case where only the pressure sensitive sheet is covered with the second protective resin so as to surround it, the durability against the stress applied from the outside by the amount covered with the second protective resin so as to surround the support plate together with the pressure sensitive sheet. Can be improved.

As described above, according to the present invention, a load detection sensor and a load detection sensor unit excellent in durability can be provided.

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 the figure which looked at a mode that a load detection sensor was fixed to a support plate from the 2nd insulating sheet side front. FIG. 6 is a cross-sectional view taken along XX in FIG. 5. FIG. 6 is a cross-sectional view taken along YY in FIG. 5. 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 a figure which shows a mode that the load detection sensor in 2nd Embodiment is fixed to a support plate from the same viewpoint as FIG. FIG. 12 is a cross-sectional view taken along XX in FIG. 11. FIG. 12 is a cross-sectional view taken along YY in FIG. 11.

Hereinafter, preferred embodiments of a load detection sensor and 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 1 includes a support plate 2, a pair of buffer members 3, an upper case 4, and a load detection sensor 5 as main components.

As shown in FIG. 2, the support plate 2 includes a placement portion 21 on which the load detection sensor 5 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. In addition, the plate | board thickness of the support plate 2 shall be 0.8 mm, for example.

A main block 50m provided with a switch SW which is a pressure sensitive element of the load detection sensor 5 described later is disposed on the surface of the main block placement portion 21m facing the seat cushion SC. Further, as shown in FIG. 2, a plurality of circular through holes 20H penetrating the support plate 2 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.

Further, 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 provided with wiring in a load detection sensor 5 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 5, and the extending direction of the tail block mounting portion 21t is set. Is made smaller than the length of the tail block 50 t of the load detection sensor 5.

The pair of hook portions 22 are respectively connected to the 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.

Also, 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. The buffer member 3 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 the spring portion via the buffer member 3 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.

Moreover, the hook part 22 has elasticity, and when the buffer member 3 is disposed in the space surrounded by the inner wall part 22A, the upper wall part 22C, and the outer wall part 22B as described above, the inner wall part 22A, The upper wall portion 22 C and the outer wall portion 22 B are configured to contact a part of the buffer member 3. A pressing portion 22PT is formed below the outer wall portion 22B, and the pressing portion 22PT is bent so as to protrude toward the main block mounting portion 21m, and the buffer member 3 is mounted on the main block by the elasticity of the hook portion 22. A pressing force acts on the mounting portion 21m side. 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 3 from three directions opposite to the main block placement portion 21m.

Each buffer member 3 is a member that softens the contact between the support plate 2 and the S spring 100. These buffer members 3 are arranged 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 2 as described above.

Each buffer member 3 includes 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 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 sandwiches the S spring 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 opening 22H of the inner wall portion 22A. 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 opening 22H of the outer wall portion 22B in a state where the buffer body 31 is disposed in the space. The

Also, the pair of guides 33 are formed on the outer side wall of the buffer body 31 from the main block mounting portion 21m side to the opposite side of the main block mounting 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 the state where the buffer member 3 is attached to the hook portion 22, the positional deviation between the buffer member 3 and the hook portion 22 is suppressed.

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

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

The Rockwell hardness of the buffer member 3 is preferably about HRR30 to HRR120, and the Rockwell hardness of the support plate 2 is preferably about HRB80 to HRC68. When the Rockwell hardness of the buffer member 3 is in the range of HRR30 to HRR120, abnormal noise due to contact between the support plate 2 and the S spring 100 can be further reduced, and deformation of the buffer member 3 due to load can be suppressed. preferable. Further, when the Rockwell hardness of the support plate 2 is in the range of HRB 80 to HRC 68, the support plate 2 is softer than the S spring 100 but has sufficient durability, which is preferable.

The upper case 4 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 4 is also a pressing member that presses the switch SW of the load detection sensor 5 by being pressed by the seat cushion SC.

The upper case 4 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. The frame wall 48 of the upper case 4 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 mounting portion 21 m of the support plate 2. By fitting each hook piece 47 into the case stopping opening 24, relative movement of the support plate 2 and the upper case 4 in the mounting surface direction of the main block mounting portion 21m is restricted.

The top wall 45 of the upper case 4 is provided with a pressing portion 46 that protrudes from the bottom surface facing the mounting portion 21 of the support plate 2. 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.

Also, the top wall 45 of the upper case 4 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 20 H formed in the mounting portion 21 of the support plate 2. In a state where the upper case 4 covers the load detection sensor 5 placed on the placement portion 21 of the support plate 2 and each hook piece 47 is fitted in each case stop opening 24, each rib 49 corresponds to the corresponding penetration. It is inserted into the hole 20H. Thereby, even if the load detection sensor 5 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 5 and the pressing portion 46 of the upper case 4 is restricted. The In the case of this embodiment, in the state where the upper case 4 covers the load detection sensor 5 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 5, but it may not be in contact.

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

When such a load detection sensor unit 1 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 4 is 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 switch SW of the load detection sensor 5.

The load detection sensor 5 is a sheet-like sensor having a switch SW that is a pressure-sensitive element, and bonds the pressure-sensitive sheet 50 having flexibility, the metal plate 60, and the pressure-sensitive sheet 50 and the metal plate 60. An adhesive layer 70, a chip-type electronic component 80, a first protective resin 18A, and a second protective resin 18B are provided. The pressure sensitive sheet 50 and the metal plate 60 are bonded together by the adhesive layer 70.

The pressure sensitive sheet 50 is a membrane switch, and has a substantially rectangular main block 50m and a tail block 50t connected to the main block 50m and narrower than the main block 50m. The main block 50 m is also a main block of the load detection sensor 5, and the tail block 50 t is also a tail block of the load detection sensor 5. 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 bonded to one surface of the pressure-sensitive 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, which is a part of the pressure sensitive sheet 50, on the seat cushion SC side.

The adhesive layer 70 is a layered member that bonds the pressure-sensitive sheet 50 and the metal plate 60 together. In the present embodiment, the adhesive layer 70 has the same size as the metal plate 60. The material of the adhesive layer 70 may be any material as long as the pressure-sensitive sheet 50 and the metal plate 60 can be bonded together. For example, a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like. Is mentioned. The adhesive layer 70 may be a double-sided tape in which an adhesive layer is formed on both surfaces of a base material such as PET or nonwoven fabric. 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. .

The chip-type electronic component 80 is a small mounting component obtained by packaging an electronic circuit into a chip shape as shown in FIGS. This chip-type electronic component 80 is disposed in the tail block 50t and is electrically connected to a switch SW that is a pressure-sensitive element. In the present embodiment, a chip-type resistor element having a resistance value smaller than the printing resistance is adopted as the chip-type electronic component 80, and the detection accuracy in the load detection sensor 5 based on the resistance value fluctuation is the printing resistance. Compared to this, it can be improved. In the present embodiment, a chip resistor element that is the chip electronic component 80 is connected in series with a switch SW that is a pressure sensitive element via a first wiring 56w described later. Thereby, even when the switch SW is turned on, a result corresponding to the resistance value of the chip-type resistance element is output. For this reason, it is possible to detect a failure such as when a first terminal 56c described later and a second terminal 57c described later are short-circuited by water or the like.

Next, the load detection sensor 5 will be described in more detail.

FIG. 4 is an exploded view of the load detection sensor 5. As shown in FIG. 4, the pressure sensitive 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 pressure-sensitive sheet 50, and a tail block 56t that is connected to the main block 56m and has substantially the same shape as the tail block 50t of the pressure-sensitive sheet 50. . The shape of the tail block 56t is different from the shape of the tail block 50t of the pressure sensitive sheet 50 in that the tip portion on the opposite side of the main block 56m has a narrower width than the other portions of the tail block 56t. Further, a through hole 56H is formed in the main block 56m at the same position as the through hole 50H of the pressure sensitive sheet 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 substantially at the 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 through the first wiring 56w, and the chip electronic component 80 is provided on the first wiring 56w. That is, the first wiring 56w has a pair, one of the pair of first wirings 56w is connected to the first electrode 56e and one end of the chip-type electronic component 80, and the other of the pair of first wirings 56w is The other end of the chip-type electronic component 80 is connected to the first terminal 56c.

The second electrode sheet 57 mainly includes a second insulating sheet 57s, a second electrode 57e, and a second terminal 57c.

The second insulating sheet 57s is disposed closer to the seat cushion SC than the first electrode sheet 56, and is a resin 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 pressure sensitive 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 the first electrode 56e, and is provided on one surface of the second insulating sheet 57s at the 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 penetrates at the same position as the through hole 50H of the pressure sensitive sheet 50 in the same manner as the first insulating sheet 56s and the second insulating sheet 57s. A hole 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 c and the space outside the pressure-sensitive 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 face each other 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 pressure sensitive sheet 50.

Further, the signal cables 19 connected to a control device (not shown) are connected to the first terminal 56c and the second terminal 57c of the pressure-sensitive sheet 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 first terminal 56c and the second terminal 57c are arranged in the opening of the connector, a connector member that can be fitted into the opening is connected to the end of the signal cable 19, and the connector member is fitted into the opening of the connector. By combining, the first terminal 56c and the second terminal 57c and the signal cable 19 may be connected.

The metal plate 60 is made of a metal plate material having a degree of flexibility that is difficult to bend compared to the pressure-sensitive 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 pressure sensitive sheet 50.

A through hole 60H is formed in the metal plate 60 at the same position as the through hole 50H of the pressure sensitive sheet 50. When the pressure sensitive sheet 50 and the metal plate 60 are overlapped, the pressure sensitive sheet 50 penetrates. The hole 50H and the through hole 60H of the metal plate 60 overlap each other. Further, when the pressure-sensitive sheet 50 and the metal plate 60 are stacked, the metal plate 60 covers the switch SW of the pressure-sensitive sheet 50 via the adhesive layer 70 so that the pressure-sensitive sheet 50 on the seat cushion side is covered. Affixed to the surface.

The chip-type electronic component 80 is provided on the exposed portion EP1 of the surface of the first insulating sheet 56s of the pressure-sensitive sheet 50 that faces the spacer 58, and is mounted on the first wiring 56w. That is, the chip-type electronic component 80 is electrically connected to the first electrode 56e constituting the pressure-sensitive element via one of the pair of first wirings 56w, and via the other of the pair of first wirings 56w. Are electrically connected to the first terminal 56c. The exposed portion EP1 is a portion exposed from the spacer 58 and the second insulating sheet 57s when the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s are laminated in this order. In addition, the metal plate 60 is disposed on the surface side opposite to the surface facing the spacer 58 in the main block 57m of the second insulating sheet 57s. For this reason, the exposed portion EP1 of the first insulating sheet 56s is exposed from the metal plate 60 without being covered by the metal plate 60. Thus, the exposed portion EP1 of the present embodiment is provided in the tail block 56t of the first insulating sheet 56s that does not overlap the spacer 58, the second insulating sheet 57s, and the metal plate 60 in the tail block 50t of the pressure-sensitive sheet 50. It is done.

In the load detection sensor 5 having the above configuration, a part of the pressure-sensitive sheet 50 is disposed on the placement portion 21 of the support plate 2 as shown in FIG. Specifically, the main block 50m of the pressure-sensitive sheet 50 having the switch SW is positioned on the main block mounting portion 21m of the support plate 2, and the tail block 50t of the pressure-sensitive sheet 50 is mounted on the tail block of the support plate 2. Located on the portion 21t. Thus, the switch SW as a pressure sensitive element is placed on the support plate 2. Further, as shown in FIG. 4, the first terminal 56c provided in the tail block 50t is located in the exposed part EP1 of the first insulating sheet 56s, and the second terminal 57c is located in the exposed part EP2 of the second insulating sheet 57s. . The exposed portion EP1 is a portion exposed from the spacer 58 and the second insulating sheet 57s when the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s are laminated in this order as described above. . The exposed portion EP2 is a portion exposed from the spacer 58 and the first insulating sheet 56s when the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s are laminated in this order. Therefore, the first terminal 56c and the second terminal 57c and the chip-type electronic component 80 are located in a region that does not overlap the support plate 2 as shown in FIG. Then, each signal cable 19 connected to the first terminal 56 c and the second terminal 57 c of the pressure-sensitive sheet 50 is led out from the support plate 2.

Thus, the chip-type electronic component 80 is fixed by the first protective resin 18 A of the load detection sensor 5 in a state where the load detection sensor 5 is disposed on the support plate 2. Further, in this state, as shown in FIG. 1, the end of the tail block 50 t of the pressure sensitive sheet 50 and the end of the tail block mounting portion 21 t of the support plate 2 are protected by the second protection of the load detection sensor 5. It is covered so as to be surrounded by the resin 18B. The second protective resin 18B includes a first terminal 56c and a second terminal 57c to which the signal cable 19 in the tail block 50t of the pressure sensitive sheet 50 is connected, a chip-type electronic component 80, the first protective resin 18A, and an exposed portion EP1. And are included. In FIG. 2, the second protective resin 18 B is separated from the support plate 2. However, since FIG. 2 is an exploded view and does not show the state of assembly, for convenience, the second protective resin 18 B is shown in a state separated from the support plate 2.

FIG. 5 is a front view of the state where the load detection sensor is fixed to the support plate from the second insulating sheet side. FIG. 6 is a cross-sectional view taken along the line XX of FIG. 5, and more specifically, a cross-sectional view of a surface along the longitudinal direction of the tail block mounting portion 21t. FIG. 7 is a cross-sectional view taken along the line YY of FIG. 5, and more specifically, a cross-sectional view of the tail block mounting portion 21t along the short direction.

As shown in FIGS. 5 to 7, the first protective resin 18A of the load detection sensor 5 in the present embodiment is provided in the exposed portion EP1, and is mounted on the first wiring 56w of the exposed portion EP1. It covers so as to enclose the entire side of 80 sides. The side of the chip type electronic component 80 is a direction orthogonal to the thickness direction of the chip type electronic component 80. In the present embodiment, the upper surface of the chip-type electronic component 80 that is the surface opposite to the mounting surface is not covered with the first protective resin 18A, but the entire outer periphery of the chip-type electronic component 80 including the upper surface is the first. 1 It may be covered with the protective resin 18A. Further, only a part around the side of the chip-type electronic component 80 may be covered with the first protective resin 18A. That is, the first protective resin 18 A only needs to cover at least a part of the side of the chip-type electronic component 80. The first protective resin 18A of the present embodiment also covers the first wiring 56w exposed in the exposed portion EP1, but the first wiring 56w may protrude from the first protective resin 18A. However, it is preferable that the first wiring 56w exposed to the exposed portion EP1 is covered with the first protective resin 18A.

The second protective resin 18B of the load detection sensor 5 in the present embodiment covers a part of the outer periphery of the pressure sensitive sheet 50. Specifically, the end portion of the tail block 50t in the pressure sensitive sheet 50 including the first terminal 56c and the second terminal 57c, the chip-type electronic component 80, the first protective resin 18A, and the exposed portions EP1 and EP2 is wrapped. Covering. That is, the exposed portion EP1 of the tail block 56t of the first insulating sheet 56s, the tail block 57t of the second insulating sheet 57s and the tail block 58t of the spacer 58 that are around the exposed portion EP1 and other than the exposed portion EP1. Is covered with the second protective resin 18B. That is, the second protective resin 18B is provided so as to surround not only the first insulating sheet 56s but also the spacer 58 and the second insulating sheet 57s laminated on the first insulating sheet 56s, and the first terminal 56c and the chip type are provided. The electronic component 80 and the first protective resin 18A are included in the second protective resin 18B. Also, the exposed portion EP2 of the tail block 57t of the second insulating sheet 57s, the tail block 56t of the first insulating sheet 56s that is around the exposed portion EP2, and other than the exposed portion EP2, and the tail block 58t of the spacer 58 Covered with the second protective resin 18B. In other words, not only the first insulating sheet 56s but also the spacer 58 laminated on the second insulating sheet 57s and the second protective resin 18B are provided so as to surround the outer periphery of the second insulating sheet 57s, and the second terminal 57c is the second terminal 57c. It is included in the protective resin 18B. 6 and 7, when the exposed portions EP1 and EP2 are viewed in cross-section along the short direction of the tail block 50t in the pressure sensitive sheet 50, the second protective resin 18B is used in the short direction. Is covered with the outer periphery of the tail block 50t. The first terminal 56c and the second terminal 57c, the chip-type electronic component 80, and the first protective resin 18A are disposed inside the second protective resin 18B. That is, the second protective resin 18B wraps around the outer periphery of the first insulating sheet 56s passing through the chip-type electronic component 80 in a direction orthogonal to the surface of the first insulating sheet 56s facing the spacer 58. In the present embodiment, the outer periphery of the first insulating sheet 56s that passes through the chip-type electronic component 80 is along the short direction of the tail block 50t. It does not have to be along the short direction of 50t. Further, for example, even when a force is applied to the second protective resin 18B from the outside and a stress due to the force is applied to the exposed portion EP1 in the first insulating sheet 56s, the chip-type electronic component 80 and the switch SW that is a pressure-sensitive element are connected. In order to easily maintain the electrical connection relationship, a reinforcing plate may be provided on the surface of the first insulating sheet 56s opposite to the spacer 58 of the exposed portion EP1.

In addition to this, the second protective resin 18B covers the tail block placing portion 21t of the support plate 2 on which the end portion is placed together with the end portion of the tail block 50t in the pressure sensitive sheet 50. . That is, as shown in FIG. 6 and FIG. 7, when the position where the second protective resin 18B is fixed to the support plate 2 is viewed in cross section, the second protective resin 18B is a tail block of the support plate 2 overlaid on each other. The outer periphery of the mounting block 21t and the tail block 50t of the pressure-sensitive sheet 50 is covered. That is, the second protective resin 18 B covers the outer periphery of the laminate composed of the support plate 2 and the pressure sensitive sheet 50.

Thus, the second protective resin 18B is fixed to the tail block mounting portion 21t of the support plate 2 together with the end portion of the tail block 50t of the pressure sensitive sheet 50 by its own adhesive force. Further, since the second protective resin 18B 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 A short circuit between the terminal 56c and the second terminal 57c due to conductive dust or the like is suppressed.

The first protective resin 18A and the second protective resin 18B are not particularly limited as long as they are resins, but the first protective resin 18A is preferably harder than the second protective resin 18B. For example, the first protective resin 18A is a thermosetting resin or photocurable resin made of an epoxy resin or the like, and the second protective resin 18B is a thermoplastic resin such as polyamide, polyester, olefin, or urethane. It is preferable.

Further, as described above, in the state where the upper case 4 covers the load detection sensor 5 placed on the support plate 2 and each hook piece 47 is fitted in each case stop opening 24, the pressing portion 46 is The tip contacts the position where the switch SW of the metal plate 60 of the load detection sensor 5 overlaps. 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 pressure sensitive sheet 50, and the through hole 20H of the support plate 2. Therefore, even when the support plate 2 and the first insulating sheet 56s are not bonded, the relative movement between the switch SW of the load detection sensor 5 and the pressing portion 46 of the upper case 4 is restricted. That is, the rib 49 can be understood as a movement regulating member that regulates relative movement between the pressure-sensitive sheet 50 and the support plate 2 in the surface direction of the support plate 2.

Such a load detection sensor unit 1 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. 8, the hook portion 22 of the support plate 2 is attached to the two S springs 100 facing each other among the plurality of S springs 100 that are arranged and stretched along the opening 151 of the seat frame 150 via the buffer member 3. Each of them can be fixed and the load detection sensor unit 1 can be attached to the seat. Further, as shown in FIG. 9, in one S spring 100 among a plurality of S springs 100 stretched side by side in the opening 151 of the frame 150, the hook portion 22 of the support plate 2 is disposed at a portion facing each other. The load detection sensor unit 1 may be attached to the seat.

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

FIG. 10 is a diagram illustrating an ON state of the load detection sensor 5. 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 4 and presses the upper surface 45S. When the lower surface of the seat cushion SC further moves downward, as shown in FIG. 10, the tip of the pressing portion 46 presses the metal plate 60, and the main block 57 m of the second insulating sheet 57 s is bent by the bending of the metal plate 60. Also bends. For this reason, the 2nd electrode 57e contacts the 1st electrode 56e, and switch SW of the load detection sensor 5 will be in an ON state. Then, seating is detected by a vehicle control unit (not shown) connected to the signal cable 19. At this time, in this embodiment, since the surface on the support plate side of the main block 56m of the first insulating sheet 56s is not bonded to the support plate 2, 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, in the load detection sensor 5 of the present embodiment, the exposed portion exposed from the spacer 58 and the second insulating sheet 57s in the surface of the first insulating sheet 56s of the pressure-sensitive sheet 50 that faces the spacer 58. EP1 is provided. The exposed portion EP1 is provided with a chip-type electronic component 80 that is connected to the first electrode 56e constituting the switch SW that is a pressure-sensitive element via the first wiring 56w. The exposed portion EP1 is provided with a first protective resin 18A that covers at least a part of the side of the chip-type electronic component 80. The load detection sensor 5 covers the chip-type electronic component 80 and the first protective resin 18A, and at least one surface of the exposed portion EP1 and the second insulating sheet 57s opposite to the surface facing the spacer 58. 2nd protective resin 18B which covers a part.

In such a load detection sensor 5, the chip-type electronic component 80 and the first protective resin 18A are covered with the second protective resin 18B, and the outer surface of the second insulating sheet 57s and the exposed surface of the first insulating sheet 56s are covered. At least part of it is covered. For this reason, even if stress is applied from the outside, the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s constituting the pressure-sensitive sheet 50 can be made difficult to peel off. The chip-type electronic component 80 is fixed to the exposed portion EP1 of the first insulating sheet 56s by the first protective resin 18A, and is further covered by the second protective resin 18B. For this reason, even if stress is applied from the outside, it is possible to easily maintain the electrical connection relationship between the chip-type electronic component 80 and the switch SW that is a pressure-sensitive element. Thus, the durability of the load detection sensor 5 can be improved.

In the case of this embodiment, the second protective resin 18B is in a direction perpendicular to the surface of the first insulating sheet 56s facing the spacer 58, and the first insulating sheet 56s passes through the chip-type electronic component 80. Wrapping the outer periphery. For this reason, it is suppressed that dust etc. adhere to chip type electronic component 80. Therefore, it is possible to reduce the size while further improving the durability.

Further, in the case of the present embodiment, the second protective resin 18B wraps not only the outer periphery of the first insulating sheet 56s but also the outer periphery of a part of the pressure sensitive sheet 50. For this reason, the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s constituting the pressure-sensitive sheet 50 can be further prevented from peeling off.

In the case of this embodiment, the pressure-sensitive sheet 50 is provided in a part different from the part where the chip-type electronic component 80 is provided in the exposed part EP1, and the first electrode 56e constituting the switch SW that is a pressure-sensitive element. It has the 1st terminal 56c electrically connected through the 1st wiring 56w. The second protective resin 18B also covers the first terminal 56c.

Thus, in this embodiment, since the first terminal 56c is also covered by the second protective resin 18B, the connection structure between the first terminal 56c and the signal cable 19 connected to the first terminal 56c is protected, and Dust and the like are prevented from adhering to the first terminal 56c. Furthermore, it is not necessary to provide a protective member for protecting the terminal separately. Therefore, it is possible to reduce the size while further improving the durability.

When the first protective resin 18A is harder than the second protective resin 18B, the second protective resin 18B absorbs externally applied stress while fixing the chip-type electronic component 80 to the exposed portion EP1 with the first protective resin 18A. Therefore, the durability can be further improved.

Further, even when the first protective resin 18A is a thermosetting resin or a photocurable resin and the second protective resin 18B is a thermoplastic resin, the chip-type electronic component is exposed to the exposed portion EP1 with the first protective resin 18A. Since the stress applied from the outside can be absorbed by the second protective resin 18B while fixing 80, the durability can be further improved. Further, when the first protective resin 18A is a thermosetting resin, it is possible to suppress the first protective resin 18A from being deformed by heat even under high temperature conditions.

Further, the load detection sensor unit 1 in the present embodiment includes a load detection sensor 5 and a support plate 2 on which the pressure sensitive sheet 50 in the load detection sensor 5 is placed. The second protective resin 18B in the load detection sensor 5 covers the tail block placement portion 21t of the support plate 2 on which the end portion is placed together with the end portion of the tail block 50t in the pressure sensitive sheet 50. ing.

In such a load detection sensor unit 1, since the pressure sensitive sheet 50 can be fixed to the support plate 2 by the second protective resin 18 B, the movement of the pressure sensitive sheet 50 relative to the support plate 2 is suppressed even if vibration or the like occurs. it can. Further, as compared with the case where only the pressure sensitive sheet 50 is covered with the second protective resin 18B so as to surround it, the amount of the pressure sensitive sheet 50 which is covered with the second protective resin 18B so as to surround the support plate 2 from the outside. Durability against applied stress can be improved.

In the case of this embodiment, the exposed portions EP1 and EP2 of the pressure sensitive sheet 50 are provided in the tail block 50t, so that the exposed portions EP1 and EP2 are separated from the switch SW provided in the main block 50m of the pressure sensitive sheet 50. be able to. In such a case, since the support plate 2 has the tail block placement portion 21t, the tail block 50t can be supported even when the tail block 50t of the pressure-sensitive sheet 50 is long. Further, since the second protective resin 18B is fixed to the end of the tail block mounting portion 21t opposite to the main block mounting portion 21m, the first terminal 56c, the second terminal 57c and the chip type in the support plate 2 are used. The second protective resin 18B can be fixed at a position closest to the electronic component 80. For this reason, the amount of the second protective resin 18B can be reduced, and the movement of the second protective resin 18B relative to the support plate 2 due to vibration or the like can be further suppressed.

In the present embodiment, the load detection sensor unit 1 includes an upper case having an upper surface 45S that is a pressure receiving surface that receives a pressing force from the seat cushion SC and a pressing portion 46 that presses the switch SW. A certain upper case 4 has a rib 49 that passes through the load detection sensor 5 and is inserted into a through hole 20 H formed in the support plate 2. For this reason, the relative position of the support plate 2 and the load detection sensor 5 in the surface direction of the support plate 2 is determined by the rib 49, and the support plate 2 of the load detection sensor 5 is defined by the second protective resin 18B and the rib 49. The positional deviation with respect to can be suppressed.

(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. 11 is a view showing a state in which the load detection sensor according to the second embodiment is fixed to the support plate from the same viewpoint as FIG. FIG. 12 is a cross-sectional view taken along the line XX of FIG. 11, and more specifically, a cross-sectional view of a surface along the longitudinal direction of the tail block mounting portion 21t. FIG. 13 is a cross-sectional view taken along the line YY of FIG. 11, and specifically, a cross-sectional view of the tail block placement portion 21t along the short direction.

As shown in FIGS. 11 to 13, in the load detection sensor of the load detection sensor unit of the present embodiment, two exposed portions EP3 and EP4 are provided on the tail block 56t of the first insulating sheet 56s of the pressure sensitive sheet 50. It is done. The exposed portion EP3 is located at the end of the tail block 56t, and the exposed portion EP3 is provided with a first terminal 56c. As in the first embodiment, the first terminal 56c is connected to the first electrode 56e via one of the pair of first wirings 56w.

The exposed part EP4 is located in the middle of the tail block 56t, and the chip-type electronic component 80 is provided on the first wiring 56w arranged in the exposed part EP4. A first protective resin 18A is provided around the side of the chip-type electronic component 80, as in the first embodiment, and the chip-type electronic component 80 is fixed to the exposed portion EP4 by the first protective resin 18A. Is done.

The second protective resin 18B is provided on the exposed portion EP4. The second protective resin 18B does not cover the surface of the first insulating sheet 56s opposite to the surface facing the spacer 58 as in the first embodiment, and the exposed portion EP4 of the first insulating sheet 56s is not covered with the second protective resin 18B. The second insulating sheet 57s around the exposed portion EP4 and a part of the spacer 58 are covered. In the present embodiment, the surface of the first insulating sheet 56s opposite to the surface facing the spacer 58 is not covered with the second protective resin 18B as in the first embodiment. Further, the second protective resin 18B covers a part of the exposed part EP4 without covering the entire exposed part EP4 as in the first embodiment. In the present embodiment, in the exposed portion EP4, the region near the side surface of the first insulating sheet is not covered with the second protective resin 18B, and only the other exposed region other than the region is covered with the second protective resin 18B. As described above, the second protective resin 18B of the present embodiment covers the chip-type electronic component 80 and the first protective resin 18A, and on the side facing the spacer 58 in a part of the exposed portion EP4 and the second insulating sheet 57s. It covers a part of the surface opposite to the surface.

In the present embodiment, since the second protective resin 18B does not cover the surface of the first insulating sheet 56s opposite to the surface facing the spacer 58 as in the first embodiment, the support plate 2 is also covered. Not. The second protective resin 18B includes a first terminal 56c disposed on the exposed portion EP3 of the first insulating sheet 56s, an exposed portion EP2 of the second insulating sheet 57s, and a second terminal disposed on the exposed portion EP2. 57c is not included. In the present embodiment, the first terminal 56c, the second terminal 57c, and the exposed portion EP2 are included in the third protective resin 18C made of a thermoplastic resin. The third protective resin 18C covers the end of the tail block 50t in the pressure sensitive sheet 50 so as to surround it. The third protective resin 18C is omitted, and the second protective resin 18B includes the exposed portions EP2 to EP4, the first terminal 56c and the second terminal 57c, the chip-type electronic component 80, and the first protective resin 18A. In a state of being included, the support plate 2 may be covered so as to surround the tail block 50t.

As described above, in the load detection sensor of the present embodiment, although the outer periphery of a part of the pressure-sensitive sheet 50 is not covered, the chip-type electronic component 80 and the first protective resin 18A are covered, and a part of the exposed part EP4 is covered. The second insulating sheet 57s covers a part of the surface opposite to the surface facing the spacer 58. For this reason, similarly to the first embodiment, even if stress is applied from the outside, the first insulating sheet 56s, the spacer 58, and the second insulating sheet 57s constituting the pressure-sensitive sheet 50 can be made difficult to peel off. The chip-type electronic component 80 is fixed to the exposed portion EP1 of the first insulating sheet 56s by the first protective resin 18A, and is further covered by the second protective resin 18B. For this reason, as in the first embodiment, even when stress is applied from the outside, it is possible to easily maintain the electrical connection relationship between the chip-type electronic component 80 and the switch SW that is a pressure-sensitive element. Thus, even in this embodiment, the durability of the load detection sensor can be improved.

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

For example, in the first embodiment, a part of the support plate 2 is covered together with the tail block 50t in the pressure-sensitive sheet 50. However, only the tail block 50t may be covered. In addition, even if an exposed part is provided in parts other than the tail block 50t of the pressure-sensitive sheet 50 in the first embodiment and the second embodiment, and a part of the pressure-sensitive sheet 50 including the exposed part is covered. good.

In the above embodiment, the upper case 4 is provided. However, in the seating sensor unit of the present invention, the upper case 4 may not be provided. Moreover, although the load detection sensor 5 has the metal plate 60, the metal plate 60 is not an essential structure. However, when the switch SW is directly pressed by the pressing portion 46, the second electrode 57e on the side pressed by the pressing portion 46 is likely to be creeped. This creep is more likely to occur as the ambient temperature around the load detection sensor unit 1 is higher. Therefore, it is preferable that the metal plate 60 is disposed on the second electrode sheet 57 as in the above embodiment. The occurrence of the creep can be suppressed by the metal plate 60. Even when the temperature changes, the flexibility of the metal does not change so much as described above. Therefore, even when the environmental temperature changes, the bending method of the metal plate 60 pressed by the pressing portion 46 does not change so much. Therefore, according to this load detection sensor unit, the change in the detection of the load due to the environmental temperature can be suppressed.

In the above embodiment, the load detection sensor 5 is placed directly on the support plate 2, but the present invention is not limited to this. For example, a housing may be disposed on the support plate 2, the main block 50m of the load detection sensor 5 may be disposed on the housing, and the tail block 50t may be led out from the housing.

In the above embodiment, the first terminal 56c and the second terminal 57c are located in a region that does not overlap the support plate 2. However, the first terminal 56 c and the second terminal 57 c may be disposed on the support plate 2. In this case, from the viewpoint of suppressing a short circuit between the support plate 2, the first terminal 56c, and the second terminal 57c, the support plate 2 is formed of an insulating member such as ceramic or resin, or the support plate 2 and the first terminal. It is preferable that an insulating layer be formed between 56c and the second terminal 57c.

In the above embodiment, the switch SW in which the first electrode 56e and the second electrode 57e face each other is used as a pressure sensitive element. However, the pressure sensitive element of the present invention is not limited to the above embodiment. For example, instead of the spacer 58, a flexible sheet-like spacer in which the opening 58 c is omitted is adopted, and the first electrode 56 e and the second electrode 56 b are opposed to each other with the spacer bent by the pressing force. A capacitance-type pressure-sensitive element that detects a load based on a capacitance that changes as the distance between the electrodes 57e becomes smaller may be applied, or other forms of pressure-sensitive elements may be used. .

In the above embodiment, the first terminal 56c is provided on the first insulating sheet 56s, and the second terminal 57c is provided on the second insulating sheet 57s. However, both the first terminal 56c and the second terminal 57c may be provided on the first insulating sheet 56s. In this case, the chip electronic component 80 can be connected in parallel to the switch SW. Even if the first terminal 56c is provided on the first insulating sheet 56s, the second terminal 57c is provided on the second insulating sheet 57s, and the chip electronic component 80 is provided on the first insulating sheet 56s, the chip electronic One end of the component 80 is connected to the first wiring 56w, and the other end of the chip-type electronic component 80 is connected to the second wiring 57w via the signal cable, so that the chip-type electronic component 80 is parallel to the switch SW. It is also possible to connect to.

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.

Further, the present invention can be used as long as the load is detected. That is, in the embodiment described above, the load detection sensor unit 1 is disposed below the vehicle seat cushion SC, and the load detection sensor unit 1 detects a load caused by a person's seating. Can be adopted. For example, the load detection sensor unit 1 may be disposed on a seat cushion (bed mat) of a care bed to detect a load caused by the presence of a person on the bed mat. The present invention can also be used to detect a pressing force as a load by disposing the load detection sensor unit 1 as a switch of an electronic device or the like.

The present invention can provide a load detection sensor unit having excellent durability, and has applicability in technical fields such as a seat device and a nursing bed.

DESCRIPTION OF SYMBOLS 1 ... Load detection sensor unit 2 ... Support plate 3 ... Buffer member 4 ... Upper case 5 ... Load detection sensor 18A ... 1st protective resin 18B ... 2nd protective resin 21 ... Placement part 21m ... Main block placement part 21t ... Tail block placement part 22 ... Hook part 50 ... Pressure sensitive sheet 50m ... Main block 50t ... Tail block 56s ... first insulating sheet 57s ... second insulating sheet 58 ... spacer 80 ... chip-type electronic component EP1 ... exposed portion SC ... sheet cushion SW ... switch (pressure-sensitive element)

Claims

A pressure sensitive sheet having a first insulating sheet and a second insulating sheet facing each other, a spacer disposed between the first insulating sheet and the second insulating sheet, and a pressure sensitive element;
A chip-type electronic component provided in an exposed portion exposed from the spacer and the second insulating sheet in a surface of the first insulating sheet facing the spacer, and electrically connected to the pressure sensitive element;
A first protective resin provided on the exposed portion and covering at least a part of the side of the chip-type electronic component;
The chip-type electronic component and the first protective resin are covered, and at least a part of the exposed portion and at least a part of a surface of the second insulating sheet opposite to the surface facing the spacer A second protective resin for covering;
A load detection sensor comprising:
The second protective resin is in a direction perpendicular to the surface of the first insulating sheet facing the spacer and wraps around the outer periphery of the first insulating sheet passing through the chip-type electronic component. The load detection sensor according to claim 1, wherein
The load detection sensor according to claim 1, wherein the second protective resin wraps a part of the outer periphery of the pressure-sensitive sheet.
The pressure-sensitive sheet is provided in a portion different from the portion where the chip-type electronic component is provided in the exposed portion, and has a terminal electrically connected to the pressure-sensitive element,
The load detection sensor according to any one of claims 1 to 3, wherein the second protective resin also covers the terminal.
The load detection sensor according to any one of claims 1 to 4, wherein the second protective resin also covers a side surface of the first insulating sheet in the exposed portion.
The load detection sensor according to any one of claims 1 to 5, wherein the first protective resin is harder than the second protective resin.
The load according to any one of claims 1 to 6, wherein the first protective resin is a thermosetting resin or a photocurable resin, and the second protective resin is a thermoplastic resin. Detection sensor.
A load detection sensor according to any one of claims 1 to 7,
A support plate on which the pressure sensitive sheet is placed;
The load detection sensor unit, wherein the second protective resin covers a part of the pressure sensitive sheet so as to surround a support plate on which the part is placed.