JP5169128B2 - Vehicle seat device provided with load detection device - Google Patents

Description

  The present invention relates to a vehicle seat device including a load detection device that measures a load of an occupant seated on a vehicle seat.

  In a vehicle equipped with an air bag to protect a passenger seated in the vehicle seat, the gas generation amount is adjusted appropriately according to the seated person when the air bag is inflated, or when the seated person is a child. In order to prevent the airbag from being operated, many vehicle seat devices including a load detection device that detects a load of a seated person have been proposed.

For example, Patent Document 1 includes a load sensor that measures a seated person's load between a seat-side fixing member that fixes a seat and a floor-side fixing member that fixes the seat-side fixing member to a vehicle floor. A vehicle seat device is disclosed. The load sensor includes a flange portion that is mounted in surface contact with the floor-side fixing member, a bolt portion that comes into contact with the flange portion and protrudes in the vertical direction and is fixed to the seat-side fixing member with a nut, a flange portion and a bolt portion. It is comprised from the sensor for affixing on the distortion | strain part provided in this junction part, and detecting the load added to an axial direction at a bolt part. A signal line is connected to the sensor via a terminal box.
JP 2004-268620 A ([Claim 1], FIG. 1-3)

  In this type of load sensor, when a load signal detected by the sensor is amplified and output in the vicinity of the sensor, an amplifier device must be provided integrally with the load sensor. In this case, it is possible to integrally attach a bracket extending laterally from the strain-generating body to which the strain gauge is attached, and to attach the amplifier device to the bracket. This is effective in reducing the height dimension of the load detecting device interposed between the two.

  However, when the both ends of the strain body are fixed to the floor side fixing member with bolts and nuts, the bracket is fixed to the floor side fixing member integrally with the strain body using the bolts and nuts. However, when tightening with bolts and nuts, there is a problem that distortion occurs in the strain generating body through the bracket due to the tightening torque, which affects the strain gauge attached to the strain generating body.

  The present invention has been made to solve the above-described conventional problems, and is a load that can suppress distortion generated in the strain generating body when the strain generating body is attached to the floor-side fixing member by the tightening nut. An object of the present invention is to provide a vehicle seat device provided with a detection device.

In order to solve the above-described problem, the invention according to claim 1 is characterized in that a seat-side fixing member that fixes a vehicle seat and a floor-side fixing member that fixes the seat-side fixing member to a vehicle floor. In the vehicle seat device provided with a load detecting device for measuring the load of an occupant seated on the vehicle seat, the attachment formed on one of the floor side fixing member and the seat side fixing member A strain body fixed at both ends with a predetermined gap from the mounting surface on the surface, and fixed to the center portion of the strain body in the vertical direction to the other of the floor side fixing member and the seat side fixing member and a connecting member fixed, a strain gauge affixed between each of the surface to the opposite end portions of the strain generating body and the central portion, the strain body both end fixing portion that will be integrally fixed to both ends of the It has, from the strain gauges An upper bracket formed by extending a mounting portion to which an amplifier device for outputting a signal is extended to the side of the vehicle seat, and the distortion body is sandwiched between both end fixing portions of the upper bracket, and the floor is pressed. First and second lower brackets having mounting holes through which a fixed shaft fixed to one of the side fixing member and the seat side fixing member is inserted, and the upper bracket and the strain body are screwed into the fixed shaft. A tightening nut for fixing to one of the floor side fixing member and the seat side fixing member, and the diameter of the tightening nut is adjusted by the tightening torque of the tightening nut via the upper bracket. It is made smaller than the diameter of the annular part formed in the said both-ends fixed part so that a strain stress may not act on.

  According to a second aspect of the present invention, in the first aspect, the floor-side fixing member includes an upper rail supported by a lower rail fixed to the floor so as to be movable in the vehicle front-rear direction, and the seat-side fixing member is The first and second lower brackets are fixed to the upper rail by a fixed shaft fixed to the upper rail.

According to a third aspect of the present invention, in the first or second aspect, a fixing hole is formed in the both-end fixing portion of the upper bracket , the annular portion is formed concentrically with the fixing hole, and the tightening is performed. That is, the outer periphery of the attaching nut is made smaller than the outer peripheral edge portion of the annular portion.

According to the first aspect of the present invention configured as described above, the fixed shaft that is press-fitted with the strain-generating body sandwiched between the both-end fixed portions of the upper bracket and fixed to one of the floor-side fixing member and the seat-side fixing member is provided. The first and second lower brackets having mounting holes to be inserted therethrough, and a tightening nut that is screwed to the fixed shaft and fixes the upper bracket and the strain body to one of the floor side fixing member and the seat side fixing member, The diameter of the mounting nut is made smaller than the diameter of the annular part formed on the fixed parts at both ends so that no strain stress is applied to the strain generating body via the upper bracket by the tightening torque of the tightening nut. The torsional stress acting on the upper bracket can be reduced by the attached torque, which can suppress the influence on the strain gauge attached to the strain-generating body and accurately It can be out.

  According to the second aspect of the present invention, the floor side fixing member is composed of an upper rail supported by the lower rail fixed to the floor so as to be movable in the vehicle front-rear direction, and the seat side fixing member is a seat frame that supports the seat cushion. Since the first and second lower brackets are fixed to the upper rail by a fixed shaft fixed to the upper rail, the strain body is distorted via the upper bracket by the tightening torque of the tightening nut. It can be attached to the upper rail so as not to generate.

According to the invention of claim 3, the fixing holes are formed in the both-end fixing portions of the upper bracket , the annular portion is formed concentrically with the fixing holes, and the outer periphery of the tightening nut is connected to the outer peripheral edge portion of the annular portion. Since it is made small, even if a strain gauge is affixed to the strain generating body in the vicinity of both ends of the lower bracket, the influence on the strain gauge can be suppressed.

  Hereinafter, a vehicle seat device including a load detection device according to an embodiment of the present invention will be described with reference to the drawings. The load detection device 10 measures the load of an occupant seated on the vehicle seat 11 shown in FIG. In FIG. 1, “upper and lower”, “left and right”, and “front and rear” indicate directions viewed from the occupant seated on the vehicle seat 11.

  In FIG. 1, a seat slide device 13 that fixes a vehicle seat 11 to a vehicle floor 12 so as to be position adjustable is a pair of lower rails 14 that are fixed to the floor 12 and extend in the front-rear direction of the vehicle, and are movable to the lower rails 14. The upper rail 16 is supported. As shown in FIGS. 1 and 6, a seat frame 17 as a seat-side fixing member that supports a seat cushion of the vehicle seat 11 is positioned via the load detection device 10 at front and rear and left and right corners. These are fixed to a mounting surface 18 formed on the upper surface of the pair of upper rails 16 as a floor side fixing member. A pair of fixed shafts 19 for fixing the load detection device 10 on the mounting surface 18 are vertically separated from each other by a predetermined distance in the front-rear direction of the vehicle at each end portion of each upper rail 16 to which the load detection device 10 is fixed. Projected to

  As shown in FIGS. 2 and 3, the load detection device 10 includes a plate-like strain generating body 20 having a substantially rectangular shape, strain gauges G <b> 1 and G <b> 2 attached to the surface of the strain generating body 20, and the strain generating body 20 at both ends. The first and second lower brackets 21 and 22 fixed to the mounting surface 18 of the upper rail 16 and the connecting member fixed to the seat frame 17 of the vehicle seat 11 in a vertical direction at the center of the strain body 20 The connecting shaft 23, the upper bracket 24 fixed at both ends to the upper surface of the strain generating body 20, and the signals from the strain gauges G1 and G2 attached to the lower surface of the mounting portion 47 of the upper bracket 24 along with the strain generating body 20 The amplifier device 27 includes an amplifier case 27a in which an amplifier substrate 26 for amplifying the signal is stored, the strain gauges G1 and G2, the FPC substrate 28 connected to the amplifier substrate 26, and the like. In FIG. 2, reference numeral 55 denotes a coating portion that protects the connection portion of the FPC board 28 with the strain gauges G1 and G2.

  As shown in FIGS. 3 and 4, the first lower bracket 21 includes a circular base portion 29 having a predetermined thickness, and one end hole 30 projecting from the base portion 29 and drilled in one end portion of the strain body 20. The inner shaft portion 31 is press-fitted into the upper shaft portion, the upper shaft portion 32 protrudes from the middle shaft portion 31, and the mounting hole 33 that is drilled through the center. The second lower bracket 23 includes a circular base portion 34 having a predetermined thickness, and a middle shaft portion 36 that is loosely fitted in the other end hole 35 that protrudes from the base portion 34 and is formed in the other end portion of the strain body 20. And a mounting hole 37 that penetrates through the center.

  One end hole 30 and the other end hole 35 are formed at both ends of the strain body 20 with a predetermined distance equal to the distance between the fixed shafts 19. In the strain generating body 20, the middle shaft portion 31 is press-fitted into the one end hole 30 until the lower surface contacts the base portions 29 and 34 of the first and second lower brackets 21 and 22, and the middle shaft portion 36 is loosely fitted into the other end hole 35. Is done. A central hole 38 is formed in the central portion of the strain body 20, and a central shaft portion 39 of the connecting shaft 23 is press-fitted into the central hole 38. A flange 40 having a thickness smaller than that of the base portions 29 and 34 of the first and second lower brackets 21 and 22 is formed at the end of the connecting shaft 23, and is in contact with the lower surface of the strain body 20. A front shaft portion 41 projects from the end surface of the middle shaft portion 39, and a fixing screw portion 42 projects from the end surface of the front shaft portion 41. When the center bracket 48 is screwed to the front shaft portion 41 in a state where the middle shaft portion 39 of the connecting shaft 23 is press-fitted into the central hole 38 of the strain body 20, the connecting shaft 23 is connected to the flange 40 and the center bracket 48. The strain body 20 is sandwiched therebetween and fixed to the strain body 20. In addition, the center shaft part 31 may not be press-fitted into the one end hole 30 but simply inserted, fitted, or bonded.

  Therefore, when a load acts on the strain generating body 20 via the connecting shaft 23, the strain generating body 20 is bent while being supported at both ends by the first and second lower brackets 21 and 22, and on the surface of the strain generating body 20. Is, between each of the first and second lower brackets 21 and 22 and the connecting shaft 23, there is a compressive strain on the first and second lower brackets 21 and 22 side and a tensile strain on the connecting shaft 23 side in proportion to the load. Arise. In order to detect these compressive strain and tensile strain, there is a half between each end portion and the center portion of the strain generating body 20, that is, between each of the first and second lower brackets 21 and 22 and the connecting shaft 23. Strain gauges G1 and G2 each having two elements constituting the bridge are attached. A full bridge is formed by the half bridges of the strain gauges G1 and G2, and an electrical signal corresponding to the deflection of the strain generating body 20, that is, the load acting on the strain generating body 20, is output. It should be noted that the compressive strain is set not only on the first and second lower brackets 21 and 22, but also on the first and second lower brackets 21 and 22 side. Alternatively, there may be a case where the tensile strain is set, or a case where the compressive strain or the tensile strain is set only on the connecting shaft 23 side.

  On the upper surface of the strain generating body 20, the upper bracket 24 is fixed to both ends of the strain generating body 20 by both end fixing portions 43 and 44. That is, fixing portions 43 and 44 are provided at both ends of the upper bracket 24, and the fixing holes 45 and 46 formed in the fixing portions 43 and 44 serve as the strain-generating body 20 of the first and second lower brackets 21 and 22. By being press-fitted into the upper shaft portion 32 and the middle shaft portion 36 that protrude from the upper surface of the upper and lower ends, the strain-generating body 20 is connected to both end fixing portions 43 and 44 of the upper bracket 24 and the first and second lower brackets 21 and 22 at both ends. It is sandwiched between the base portions 29 and 34. The upper bracket 24 is formed with an attachment portion 47 for connecting the both end fixing portions 43 and 44 so as to extend laterally from the upper surface of the strain body 20. By preventing the upper bracket 24 from overlapping with the strain-generating body 20 other than the both-end fixing portions 43 and 44, that is, the mounting portion 47, the upper bracket 24 does not affect the deformation of the strain-generating body 20, and the occupant Can be accurately measured.

  As shown in FIGS. 5 and 7, concentric with the fixing holes 45, 46 on the opposite end fixing portions 43, 44 of the upper bracket 24 on the side facing the center bracket 48 attached to the central portion of the strain body 20. Annular portions 51 and 52 are formed. Thus, a region where the strain cages G1 and G2 can be attached is secured on the surface of the strain body 20 between the both end fixing portions 43 and 44 of the upper bracket 24 and the center bracket 48.

  For example, a resin-made amplifier case 27 a is attached to the attachment portion 47 of the upper bracket 24 along with the strain body 20 by screws 49. The amplifier case 27a can be reduced in weight and cost by being made of resin. In the amplifier case 27a, an amplifier board 26 for amplifying signals from the strain gauges G1 and G2 is accommodated so as to be positioned on the same plane as the surface of the strain body 20 to which the strain gauges G1 and G2 are attached. Yes. The amplifier case 27a is provided with a connector 59 for connecting a communication line for transmitting the output of the amplifier board 26 to an unillustrated electronic control unit.

  As shown in FIG. 6, on both the left and right sides of the seat frame 17 of the vehicle seat 11, connection surfaces 62 that are opposed to the mounting surface 18 of the upper rail 16 in the vertical direction are formed. The connection surface 62 has a connection hole 63 through which the connection shaft 23 of the load detection device 10 is inserted, and insertion holes 64 (see FIG. 6) through which the tightening nuts 60 are inserted on both sides of the connection hole 63.

  The mounting holes 33 and 37 of the first and second lower brackets 21 and 22 are fitted to the fixed shaft 19 projecting vertically from the end of the upper rail 16, and the bottom surfaces of the base portions 29 and 34 are mounted on the mounting surface 18. Sit on top. The tightening nut 60 screwed to the threaded portion engraved at the tip of the fixed shaft 19 presses the both-end fixed portions 43 and 44 of the upper bracket 24, so that the strain body 20 of the load detecting device 10 becomes the upper rail. The fixing surface 18 is fixed at both ends with a predetermined gap from the mounting surface 18.

  At this time, as shown in FIGS. 6 and 7, the tightening nut 60 is moved away from the outer peripheral edge portions 51a, 52a of the annular portions 51, 52 formed in the both end fixing portions 43, 44 of the upper bracket 24. When the diameter of the tightening nut 60 is reduced and a tightening torque is generated by tightening the tightening nut 60, a strain stress is generated in the strain generating body 20 via the annular portions 51 and 52 of the upper bracket 24. The applied strain gauges G1 and G2 are not affected.

  That is, when the tightening nut 60 is tightened, a torsional stress due to the tightening torque is generated in the annular portions 51 and 52 of the upper bracket 24 that are in surface contact with the lower surface of the tightening nut 60. Although it acts on the strain gauges G1 and G2 which are exerted on both ends of the strain generating body 20 which are in surface contact with the lower surfaces of the both-end fixed portions 43 and 44 and are attached in the vicinity thereof, in this embodiment, FIG. 2, the diameter (radius R1) of the tightening nut 60 is reduced to reduce the torsional torque generated by tightening the tightening nut 60, and the both end fixing portions 43 and 44 of the upper bracket 24 and the strain body 20 are reduced. The strain stress generated at both ends of the slab is reduced, so that the influence on the strain gauges G1 and G2 can be suppressed. That is, by tightening the tightening nut 60 by making the diameter (radius R1) of the tightening nut 60 sufficiently smaller than the diameter (radius R2) of the outer peripheral edge portion 52a (51a) of the annular portion 52 (51). The torsional stress generated in the annular portion 52 (51) can be reduced.

  A connecting surface 62 is formed on the seat frame 17 of the vehicle seat 11, and a connecting hole 63 is formed in the connecting surface 62. A connecting hole 63 is fitted into the fixing screw portion 42 of the connecting shaft 23, the lower surface of the connecting surface 62 comes into contact with the upper surface of the center bracket 48, and the seat frame 17 is placed on the upper rail 16 via the strain body 20. The fastening nut 65 screwed to the fixing screw portion 42 presses the connecting surface 62 to the center bracket 48, whereby the connecting shaft 23 of the load detecting device 10 is fixed to the seat frame 17 of the vehicle seat 11.

  As described above, the amplifier device 27 and the connector 59 are provided side by side on the lateral side of the vehicle seat 11 from the mounting surface 18 of the upper rail 16 and the connecting surface 62 of the seat frame 17 facing each other. The height (vertical direction) dimension of the load detection device 10 accommodated between the mounting surface 18 of the upper rail 16 and the connecting surface 62 of the seat frame 17 can be made extremely small. That is, between the mounting surface 18 of the upper rail 16 and the connecting surface 62 of the seat frame 17, as shown in FIG. 6, the thicknesses of the base portions 29 and 34 of the first and second lower brackets 21 and 22, It suffices if there is a small gap corresponding to the sum of the thickness of the strain body 20 and the thickness of the upper bracket 24, and the amplifier rail 27 and the connector 59 are integrally disposed on the strain body 20. The distance C1 between the mounting surface 18 and the connecting surface 62 of the seat frame 17 can be reduced.

  In the vehicle seat device including the load detection device 10 configured as described above, when the occupant sits on the seat cushion, the occupant's load is applied to the strain body 20 via the connecting shaft 23. As a result, the central portion of the strain generating body 20 supported at both ends by the first and second lower brackets 21 and 22 is bent, and the first and second lower brackets 21 and 22 are formed on the surface of the strain generating body 20. Between the first and second lower brackets 21 and 22 and tensile strain on the connecting shaft 23 side in proportion to the load. These compressive strain and tensile strain are detected by the strain gauges G1 and G2 attached to the strain generating body 20. The detection outputs of the strain gauges G1 and G2 are amplified by the amplifier board 26, and the output of the amplifier board 26 is supplied to the connector 59. It is transmitted to the electronic control unit 58 via the connected communication line. In this manner, the load on the occupant seated on the vehicle seat 11 is measured based on the strain of the strain body 20. And based on this load detection result, an airbag etc. can be appropriately controlled now according to a passenger | crew's weight.

  According to the above-described embodiment, the mounting holes 33 and 37 are inserted through the fixed shaft 19 that is press-fitted with the strain-generating body 20 sandwiched between both ends of the upper bracket 24 and fixed to the upper rail (floor side fixing member) 16. The first and second lower brackets 21 and 22 formed, and a fastening nut 60 that is screwed to the fixed shaft 19 and fixes the upper bracket 24 and the strain body 20 to the upper rail (floor side fixing member) 16 are provided. The diameter of the nut 60 is reduced to such an extent that no strain stress is applied to the strain generating body 20 via the upper bracket 24 due to the tightening torque of the tightening nut 60, so that the upper bracket 24 is tightened by the tightening torque of the tightening nut 60. The acting torsional stress can be reduced, thereby suppressing the influence on the strain gauges G1 and G2 attached to the strain generating body 20, and the occupant's So heavy can be accurately detected.

  Further, annular portions 51 and 52 concentric with the fixing holes 45 and 46 are formed at both ends of the upper bracket 24, and the outer periphery of the tightening nut 60 is kept away from the outer peripheral edge portions 51a and 52a of the annular portions 51 and 52. Therefore, even if the strain gauges G1 and G2 are affixed to the strain body 20 in the vicinity of both ends of the lower bracket 24, the influence of the tightening nut 60 on the strain gauges G1 and G2 can be suppressed.

  In the embodiment described above, the first and second lower brackets 21 and 22 are fixed to the upper rail (floor side fixing member) 16 and the connecting shaft 23 is fixed to the seat frame (seat side fixing member) 17. The first and second lower brackets 21 and 22 may be fixed to the seat frame 17 and the connecting shaft 23 may be fixed to the upper rail 16.

It is a perspective view which shows a vehicle seat. It is a front view of a load detection apparatus. It is the figure which decomposed | disassembled the load detection apparatus. It is a figure which shows the assembly | attachment to the strain body of each bracket and a connection shaft. It is a perspective view of the assembled load detection apparatus. It is a figure which shows the assembly | attachment state to the vehicle of a load detection apparatus. It is the figure seen from the arrow 7 direction of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Load detection apparatus, 11 ... Vehicle seat, 12 ... Floor, 13 ... Seat slide apparatus, 14 ... Lower rail, 16 ... Floor side fixing member (upper rail), 17 ... Seat side fixing member (seat frame), 18 ... Installation Surface, 19: Fixed shaft, 20: Strain body, G1, G2: Strain gauge, 21, 22: First and second lower brackets, 23: Connection member (connection shaft), 24: Upper bracket, 27: Amplifier device , 29, 34 ... base part, 33, 37 ... mounting hole, 43, 44 ... both ends fixing part, 45, 46 ... fixing hole, 47 ... mounting part, 48 ... center bracket, 51, 52 ... annular part, 51a, 52a ... outer edge part, 60 ... clamping nut.

Claims (3)

A seat-side fixing member that fixes a vehicle seat and a floor-side fixing member that fixes the seat-side fixing member to a vehicle floor, and measures a load of an occupant seated on the vehicle seat. In a vehicle seat device provided with a load detection device for
A strain generating body fixed at both ends with a predetermined gap from the mounting surface on the mounting surface formed on one of the floor side fixing member and the seat side fixing member,
A connecting member fixed in the vertical direction to the center of the strain generating body and fixed to the other of the floor side fixing member and the seat side fixing member;
A strain gauge affixed between the both end portions and the central portion on the surface of the strain generating body;
With both ends fixed portion that will be integrally fixed to both ends of the strain body, a mounting portion mounted an amplifier device for outputting a signal from the strain gauge extending laterally of the vehicle seat The formed upper bracket,
First and second mounting holes are formed in which both the fixed portions of the upper bracket are press-fitted by sandwiching the strain-generating body and the fixing shaft fixed to one of the floor-side fixing member and the seat-side fixing member is inserted. Lower bracket,
A fastening nut screwed to the fixed shaft and fixing the upper bracket and the strain body to one of the floor side fixing member and the seat side fixing member;
The diameter of the tightening nut is made smaller than the diameter of the annular portion formed in the both-end fixed portion so that no strain stress is applied to the strain generating body via the upper bracket by the tightening torque of the tightening nut. A vehicle seat device comprising a load detection device characterized by the above.   2. The floor-side fixing member according to claim 1, wherein the floor-side fixing member includes an upper rail supported by a lower rail fixed to the floor so as to be movable in the vehicle front-rear direction, and the seat-side fixing member includes a seat frame that supports a seat cushion. The first and second lower brackets are fixed to the upper rail by a fixed shaft fixed to the upper rail, and the vehicle seat device includes a load detection device. In Claim 1 or Claim 2, a fixing hole is formed in the both-ends fixing part of the upper bracket , the annular part is formed concentrically with the fixing hole, and the outer periphery of the tightening nut is connected to the annular part. A vehicle seat device including a load detection device that is smaller than an outer peripheral edge portion.

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