Vehicular seat

Abstract

To provide a vehicular seat that can detect a reclining angle of a seat back in a method which is different from a method using a rotary encoder.SOLUTION: A vehicular seat 10 is provided with a seat cushion 12 that supports the hip of a seated occupant from below, and a seat back 14 which supports the back of the seated occupant from a rear side of the seat and is arranged to be reclinable in a longitudinal direction of the seat. A spiral spring 26 that energizes the seat back 14 in the longitudinal direction of the seat is provided between the seat cushion 12 and the seat back 14. A strain gauge 28 whose output values vary accompanying reclining of the seat back 14 is provided on the spiral spring 26 or a member to which force of the spiral spring 26 is inputted.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle seat. [Background technology]

[0002] Patent Document 1 below discloses a vehicle occupant restraint system that appropriately controls the positional relationship between a vehicle seat and an airbag. The vehicle occupant restraint system described in this document includes an airbag that deploys from the roof of the vehicle compartment toward the underside of the vehicle compartment, and a seat control unit that controls at least one of the position and posture of the vehicle seat. This makes it possible to appropriately control the positional relationship between the vehicle seat and the airbag. Furthermore, the vehicle occupant restraint system described in this document detects the reclining angle of the seatback using a rotary encoder that detects the rotational position of the output shaft of a reclining motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-41242 Summary of the Invention [Problem to be solved by the invention]

[0004] However, depending on the configuration of the vehicle seat, it may be necessary to detect the reclining angle of the seat back using a method other than the method using a rotary encoder.

[0005] SUMMARY OF THE INVENTION In consideration of the above, an object of the present invention is to provide a vehicle seat that can detect the reclining angle of a seat back using a method other than the method using a rotary encoder. [Means for solving the problem]

[0006] The vehicle seat of the first embodiment comprises a seat cushion that supports the buttocks of a seated occupant from below, a seat back that supports the back of the seated occupant from the rear side of the seat and is reclined in the fore-and-aft direction of the seat, a biasing member that is provided between the seat cushion and the seat back and biases the seat back in the fore-and-aft direction of the seat, and a strain gauge that is provided on the biasing member or a member to which the force of the biasing member is input and whose output value changes as the seat back is reclined.

[0007] In the vehicle seat of the first aspect, a biasing member is provided between the seat cushion and the seat back to bias the seat back toward the front of the seat. The biasing member or a member to which the force of the biasing member is input is provided with a strain gauge whose output value changes as the seat back is reclined. In this configuration, the reclining angle of the seat back can be detected by using the output value of the strain gauge.

[0008] A vehicle seat according to a second aspect is the vehicle seat according to the first aspect, wherein the strain gauge is attached to the biasing member.

[0009] In the vehicle seat of the second aspect, the reclining angle of the seat back can be detected by detecting the strain generated in the biasing member with a strain gauge.

[0010] A vehicle seat according to a third aspect is the vehicle seat according to the first aspect, wherein the strain gauge is attached to a biasing member locking portion to which the biasing member is locked.

[0011] In the vehicle seat of the third aspect, the reclining angle of the seat back can be detected by detecting the strain generated in the biasing member engaging portion with a strain gauge.

[0012] A fourth aspect of the vehicle seat is a vehicle seat according to any one of the first to third aspects, further comprising a reclining angle ECU to which the strain gauge is connected and which outputs a signal corresponding to the reclining angle of the seat back, and the reclining angle ECU stores a correspondence between the reclining angle of the seat back and the output value of the strain gauge.

[0013] In the fourth aspect of the vehicle seat, a strain gauge is connected to the reclining angle ECU. This reclining angle ECU outputs a signal corresponding to the reclining angle of the seat back. In this configuration, the reclining angle ECU can store the correspondence between the reclining angle of the seat back and the output value of the strain gauge.

[0014] The vehicle seat of the fifth aspect is the vehicle seat of the first aspect, further comprising a sensor bracket that displaces together with the seat back and to which the strain gauge is attached, and when the seat back is reclined forward from a state in which the reclining angle is located within a predetermined range, the sensor bracket deforms the biasing member, and when the seat back is reclined backward from a state in which the reclining angle is located within a predetermined range, the sensor bracket deforms the biasing member.

[0015] In a fifth aspect of the vehicle seat, when the seat back is reclined forward within a predetermined range, the sensor bracket deforms the biasing member. When the biasing member deforms, a load associated with the deformation of the biasing member is input from the biasing member to the sensor bracket. That is, when the forward reclining angle of the seat back changes within the predetermined range, the output value of the strain gauge attached to the sensor bracket changes. In this configuration, the forward reclining angle of the seat back can be detected by using the output value of the strain gauge. On the other hand, when the seat back is reclined backward within the predetermined range, the sensor bracket deforms the biasing member. When the biasing member deforms, a load associated with the deformation of the biasing member is input from the biasing member to the sensor bracket. That is, when the rearward reclining angle of the seat back changes within the predetermined range, the output value of the strain gauge attached to the sensor bracket changes. In this configuration, the rearward reclining angle of the seat back can be detected by using the output value of the strain gauge. [Effects of the Invention]

[0016] The vehicle seat according to the present invention has the excellent effect of being able to detect the reclining angle of the seat back using a method different from the method using a rotary encoder. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a side view schematically showing a vehicle seat according to a first embodiment. [Figure 2] FIG. 2 is a side view showing a reclining device and a reclining angle detection device. [Figure 3] 10 is an exploded perspective view showing a portion of a vehicle seat according to a second embodiment in which a reclining angle detection device is provided. FIG. [Figure 4] FIG. 10 is a perspective view showing a configuration in which a sensor bracket and a connector of a strain gauge are fixed to a back frame via a common fixing bracket. [Figure 5] 10 is a side view of the tilt shaft, coil spring, retainer, and sensor bracket as viewed from the outside in the seat width direction, showing a state in which the reclining angle of the seat back is within a predetermined range. FIG. [Figure 6] 10 is a side view of the tilt shaft, coil spring, retainer, and sensor bracket as viewed from the outside in the seat width direction, showing a state in which the seat back is reclined forward within a predetermined range. FIG. [Figure 7] 10 is a side view of the tilt shaft, coil spring, retainer, and sensor bracket as viewed from the outside in the seat width direction, showing a state in which the seat back is reclined rearward within a predetermined range. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] (First embodiment) A vehicle seat 10 according to a first embodiment of the present invention will be described using Figures 1 and 2. In the figures, the arrow FR indicates the front side of the seat, the arrow UP indicates the upper side of the seat, the arrow RH indicates the right side in the seat width direction, and the arrow LH indicates the left side in the seat width direction. In the following description, unless otherwise specified, when referring to front-rear, up-down, and left-right directions, these refer to front-rear in the front-rear direction of the seat, up-down in the seat up-down direction, and left-right in the seat width direction.

[0019] 1, a vehicle seat 10 of this embodiment includes a seat cushion 12 that supports the buttocks of a seated occupant from below, a seat back 14 that supports the back of the seated occupant from the rear, and a headrest 16 that supports the head of the seated occupant from the rear. The vehicle seat 10 also includes a reclining device 18 that reclines the seat back 14 in the front-to-rear direction relative to the seat cushion 12, and a reclining angle detection device 20 that detects the reclining angle of the seat back 14.

[0020] As shown in FIGS. 1 and 2, the reclining device 18 is provided between a cushion frame 22 that forms the framework of the seat cushion 12 and a back frame 24 that forms the framework of the seat back 14. When the reclining device 18 is in a locked state, the tilting of the back frame 24 relative to the cushion frame 22 is restricted. This restricts the reclining (front-rear tilting) of the seat back 14 relative to the seat cushion 12. On the other hand, when the reclining device 18 is released by a seated occupant operating a reclining lever (not shown), the tilting of the back frame 24 relative to the cushion frame 22 is permitted. This allows the reclining (front-rear tilting) of the seat back 14 relative to the seat cushion 12. As shown in FIG. 2, the reclining device 18 also includes a spiral spring 26 as a biasing member that rotationally biases the back frame 24 relative to the cushion frame 22. A radially inner end 26A of the spiral spring 26 is engaged with a first locking portion 22A, which serves as a biasing member locking portion, and is fixed to the cushion frame 22. A radially outer end 26B of the spiral spring 26 is engaged with a second locking portion 24A, which serves as a biasing member locking portion, and is fixed to the back frame 24. A portion of the spiral spring 26 between the radially inner end 26A and the radially outer end 26B forms a spirally wound wound portion 26C. The back frame 24 is urged to rotate forward relative to the cushion frame 22 by the spiral spring 26. That is, the seat back 14 is urged to rotate forward relative to the seat cushion 12. Here, as the rearward reclining angle of the seat back 14 relative to the seat cushion 12 increases, the amount of deflection of the wound portion 26C of the spiral spring 26 increases. As a result, as the reclining angle of the seat back 14 toward the rear side relative to the seat cushion 12 increases, the biasing force toward the front side of the seat back 14 increases.

[0021] As shown in FIGS. 1 and 2, the reclining angle detection device 20 includes a strain gauge 28 attached to the reclining device 18, and a reclining angle ECU 30 to which the strain gauge 28 is connected.

[0022] As shown in FIG. 2 , the strain gauge 28 changes its resistance value, which is its output value, as it deforms together with the component to which it is attached. In this embodiment, the strain gauge 28 is attached to the second engaging portion 24A. As indicated by the two-dot chain line in FIG. 2 , the strain gauge 28 may be attached to the first engaging portion 22A or to the wound portion 26C of the spiral spring 26. As described above, as the rearward reclining angle of the seat back 14 relative to the seat cushion 12 increases, the amount of deflection of the wound portion 26C of the spiral spring 26 increases. As a result, as the rearward reclining angle of the seat back 14 relative to the seat cushion 12 increases, the amount of deformation of the second engaging portion 24A, to which the radially outer end 26B of the spiral spring 26 is engaged, increases. As a result, as the reclining angle of the seat back 14 relative to the seat cushion 12 changes, the output value of the strain gauge 28 changes.

[0023] 1 and 2, the reclining angle ECU 30 outputs a signal corresponding to the reclining angle of the seat back 14. The reclining angle ECU 30 stores the correspondence between the reclining angle of the seat back 14 and the output value of the strain gauge 28 when the vehicle seat 10 is inspected after completion.

[0024] (Actions and Effects of This Embodiment) Next, the operation and effects of this embodiment will be described.

[0025] As described above, in the vehicle seat 10 of this embodiment, when the reclining angle of the seat back 14 relative to the seat cushion 12 changes, the output value of the strain gauge 28 attached to the second engaging portion 24A changes. In this configuration, the reclining angle of the seat back 14 can be detected by using the output value of the strain gauge 28. That is, the reclining angle of the seat back 14 can be detected by a method different from a method using a rotary encoder. In particular, in this embodiment, the correspondence between the reclining angle of the seat back 14 and the output value of the strain gauge 28 is stored during the final inspection of the vehicle seat 10, so that the reclining angle of the seat back 14 can be detected with high accuracy.

[0026] Similarly, in a configuration in which the strain gauge 28 is attached to the first locking portion 22A or the spiral spring 26, the reclining angle of the seat back 14 can be detected by using the output value of the strain gauge 28.

[0027] (Second embodiment) Next, a vehicle seat 32 according to a second embodiment of the present invention will be described with reference to Figures 3 to 7. Note that, in the vehicle seat 32 according to the second embodiment, members and parts corresponding to those of the vehicle seat 10 according to the first embodiment described above will be assigned the same reference numerals as those corresponding to those of the vehicle seat 10 according to the first embodiment, and descriptions thereof may be omitted.

[0028] As shown in Fig. 3, the vehicle seat 32 of this embodiment is configured so that the seat back 14 reclines when the seat motor is activated. As shown in Fig. 3, a reclining angle detection device 20 that detects the reclining angle of the seat back 14 is provided at the engagement portion between the back frame 24 and the cushion frame 22. The reclining angle detection device 20 is configured with a coil spring 34, a retainer 36, a sensor bracket 38, and a strain gauge 28 as its main elements.

[0029] The coil spring 34 includes a wound portion 34A wound in an annular shape, a first extending portion 34B extending upward from the front side of the wound portion 34A, and a second extending portion 34C extending upward from the rear side of the wound portion 34A. The coil spring 34 is supported by the tilting shaft 40 of the cushion frame 22 with the wound portion 34A inserted into the tilting shaft 40. A spacer 41 is inserted between the wound portion 34A and the tilting shaft 40, and a washer 42 is provided on the back frame 24 side of the wound portion 34A. A push nut 44 is engaged with the tilting shaft 40. This keeps the coil spring 34 supported by the tilting shaft 40.

[0030] The retainer 36 is fixed to the cushion frame 22 above the tilting shaft 40. The front end of the retainer 36 forms a first limiting portion 36A that is bent outward in the seat width direction. The rear end of the retainer 36 forms a second limiting portion 36B that is bent outward in the seat width direction. The first limiting portion 36A and the second limiting portion 36B of the retainer 36 are disposed between the first extending portion 34B and the second extending portion 34C of the coil spring 34.

[0031] The sensor bracket 38 is fixed to the back frame 24 above the tilt shaft 40 and above the retainer 36. The front end of the sensor bracket 38 forms a load input portion 38A that is bent outward in the seat width direction. The strain gauge 28 is fixed to the load input portion 38A. The load input portion 38A is disposed between the first extending portion 34B and the second extending portion 34C of the coil spring 34. As shown in FIG. 4, the sensor bracket 38 and the connector 46 of the strain gauge 28 may be fixed to the back frame 24 via a common fixing bracket 48.

[0032] (Actions and Effects of This Embodiment) Next, the operation and effects of this embodiment will be described.

[0033] 5 shows a side view of the tilt shaft 40, the coil spring 34, the retainer 36, and the sensor bracket 38 as viewed from the outside in the seat width direction. The range indicated by the angle θ indicates the range in which the seat back 14 can be reclined (the range in which the tilt shaft 40 can rotate). As shown in FIGS. 1 and 5, when the reclining angle of the seat back 14 is within a predetermined range, the load input portion 38A of the sensor bracket 38 is spaced apart from the first extension portion 34B and the second extension portion 34C of the coil spring 34 in the seat front-rear direction. Furthermore, when the reclining angle of the seat back 14 is within a predetermined range, the first limiting portion 36A and the second limiting portion 36B of the retainer 36 are in contact with the first extension portion 34B and the second extension portion 34C of the coil spring 34, respectively.

[0034] 1 and 6, when the seat back 14 is reclined forward within a predetermined range, the load input portion 38A of the sensor bracket 38 presses the first extension portion 34B of the coil spring 34 forward. This causes the wound portion 34A of the coil spring 34 to bend, displacing the first extension portion 34B forward. When the first extension portion 34B of the coil spring 34 displaces forward, the first extension portion 34B of the coil spring 34 moves away from the first restricting portion 36A of the retainer 36, as shown by arrow A1 in FIG. 6. When the first extension portion 34B of the coil spring 34 displaces forward, a load associated with the deformation of the coil spring 34 is input from the first extension portion 34B of the coil spring 34 to the load input portion 38A of the sensor bracket 38. That is, when the forward reclining angle of the seat back 14 relative to the seat cushion 12 changes within a predetermined range, the output value of the strain gauge 28 attached to the load input portion 38A of the sensor bracket 38 changes. In this configuration, the output value of the strain gauge 28 can be used to detect the forward reclining angle of the seat back 14.

[0035] 1 and 7, when the seat back 14 is reclined rearward within a predetermined range, the load input portion 38A of the sensor bracket 38 presses the second extension portion 34C of the coil spring 34 rearward. This causes the wound portion 34A of the coil spring 34 to bend, displacing the second extension portion 34C rearward. When the second extension portion 34C of the coil spring 34 displaces rearward, the second extension portion 34C of the coil spring 34 moves away from the second limiting portion 36B of the retainer 36, as shown by arrow A2 in FIG. 7. When the second extension portion 34C of the coil spring 34 displaces rearward, a load associated with the deformation of the coil spring 34 is input from the second extension portion 34C of the coil spring 34 to the load input portion 38A of the sensor bracket 38. That is, when the rearward reclining angle of the seat back 14 relative to the seat cushion 12 changes within a predetermined range, the output value of the strain gauge 28 attached to the load input portion 38A of the sensor bracket 38 changes. In this configuration, the output value of the strain gauge 28 can be used to detect the rearward reclining angle of the seat back 14.

[0036] As described above, in the vehicle seat 32 of this embodiment, the output value of the strain gauge 28 can be used to detect the reclining angle of the seat back 14.

[0037] The above describes one embodiment of the present invention, but the present invention is not limited to the above, and it goes without saying that it can be implemented in various other modified forms within the scope of the gist of the present invention. [Explanation of symbols]

[0038] 10 Vehicle seats 12 seat cushions 14 Seat back 22A First locking portion (biasing member locking portion) 24A Second locking portion (biasing member locking portion) 26 Spiral spring (biasing member) 28 Strain gauge 34 Coil spring (biasing member) 30 Reclining angle ECU 38 Sensor bracket

Claims

1. a seat cushion that supports the buttocks of a seated occupant from below; a seat back that supports the back of a seated occupant from the rear side of the seat and is reclined in the front-to-rear direction of the seat; a biasing member provided between the seat cushion and the seat back and biasing the seat back in the seat front-rear direction; a strain gauge provided on the biasing member or on a member to which the force of the biasing member is input, the strain gauge having an output value that changes in response to the reclining of the seat back; A vehicle seat comprising:

2. 2. The vehicle seat according to claim 1, wherein the strain gauge is attached to the biasing member.

3. 2. The vehicle seat according to claim 1, wherein the strain gauge is attached to a biasing member engaging portion to which the biasing member is engaged.

4. a reclining angle ECU connected to the strain gauge and outputting a signal corresponding to the reclining angle of the seat back; 4. The vehicle seat according to claim 1, wherein the reclining angle ECU stores a correspondence relationship between the reclining angle of the seat back and the output value of the strain gauge.

5. a sensor bracket that displaces together with the seat back and to which the strain gauge is attached; When the seat back is reclined forward from a state in which the reclining angle is within a predetermined range, the sensor bracket deforms the biasing member, 2. The vehicle seat according to claim 1, wherein the sensor bracket deforms the biasing member when the seat back is reclined rearward from a position where the reclining angle is within a predetermined range.

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