JP2009220744A - Framework structure for vehicular seat - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a framework structure for a vehicular seat capable of effectively absorbing the impact in a rear-end collision. <P>SOLUTION: An impact transmitting pin 50 is provided on a base frame 4 for supporting a seat frame 1. An impact absorbing bracket 7 is erected in a vicinity of a front end of a movable rail 32. The bracket 7 has a pin storage opening part 75 for storing the pin 50, and a pair of plate-like opposing parts 77, 78 for demarcating a guide groove 76 to be communicated with the pin storage opening part. The width of the guide groove 76 corresponding to the space between the pair of plate-like opposing parts 77, 78 is smaller than the diameter of the pin 50. During a rear-end collision, as the base frame 4 is raised, the impact transmitting pin 50 is upwardly moved while bending and deforming the plate-like opposing parts 77, 78 so as to increase the width of the guide groove 76, and the impact during the rear-end collision is absorbed or mitigated. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a vehicle seat including a seat frame constituting a skeleton of a seat cushion, a back frame constituting a skeleton of a seat back, and a slide rail mechanism for sliding the seat and the back frame back and forth. The present invention relates to a frame structure.

  Conventionally, various techniques for absorbing or mitigating an impact acting on an occupant when a vehicle receives a collision from behind (during a rear collision) have been proposed. As one of this kind of technology, when an impact is input from the rear of the vehicle body, the seat cushion is tiltably supported so that the front portion of the seat cushion is lifted with the movement of the center of gravity of the occupant. 2. Description of the Related Art A vehicle seat that absorbs or relaxes an impact by attenuating the tilt of the vehicle with a resistance generating means is known.

  For example, the shock absorbing structure for a vehicle seat disclosed in Patent Document 1 includes resistance generating means provided between a side bracket (7) and a seat rail (5) attached to both sides of the seat cushion (2). The damper (16) is provided. This damper is comprised from the cylinder member (20) and the piston member (21) slidably fitted in the cylinder member. The piston member (21) has a rod portion (21a) and a piston portion (21b) that is formed at the lower end of the rod portion and has a large diameter and is slidable along the inner peripheral surface (20a) of the cylinder member. is doing. The cylinder member (20) is formed so that its inner peripheral surface (20a) has a gentle taper shape whose inner diameter gradually decreases toward the upper side.

  At the time of rear collision, the piston member is displaced upward relative to the cylinder member. The rear impact is attenuated based on the frictional resistance between the inner peripheral surface (20a) of the cylinder member and the piston portion (21b) at that time. In particular, since the inner peripheral surface (20a) of the cylinder member has a tapered shape, the friction damping action gradually increases with an increase in the inclination angle of the seat cushion, so that the damping action according to the magnitude of the input impact is obtained. can get.

JP 2007-161049 A

  However, in the technique of Patent Document 1, the impact at the time of rear collision is absorbed based on the frictional resistance between the cylinder member and the piston member. For this reason, in order to obtain a desired shock absorption characteristic at the time of rear collision, it is necessary to greatly increase the processing accuracy of the inner peripheral surface (20a) of the cylinder member and the processing accuracy of the piston portion (21b) of the piston member. . In addition, it is necessary to improve the assembly accuracy of the piston member with respect to the cylinder member.

  The objective of this invention is providing the frame structure of the vehicle seat which can absorb or relieve | moderate effectively the impact at the time of a rear collision. More specifically, the shock absorption characteristics can be easily set without the processing accuracy of individual members constituting the shock absorption structure and the assembly accuracy of the members having an excessive influence on the shock absorption characteristics. Another object of the present invention is to provide a framework structure for a vehicle seat that enables mass production of a product with stable shock absorbing performance.

  The invention according to claim 1 is slidable along a fixed rail so that the seat frame constituting the skeleton of the seat cushion, the back frame constituting the skeleton of the seat back, and the seat and the back frame can be slid back and forth. A vehicle seat frame structure including a slide rail mechanism having a movable rail, wherein the vehicle seat frame structure is further supported by the movable rail to support the seat frame. An impact erected near the front end of the movable rail to provide a base frame, an impact transmission pin provided at or near the front end of the base frame, and a plate-like portion deformed by the impact transmission pin. An absorption bracket, and the base frame has at least a front end portion thereof away from the movable rail when a rear collision occurs. The shock absorbing bracket is provided so as to be able to hold, the pin receiving opening formed so as to be able to receive the shock transmitting pin, and the pin receiving opening located above the pin receiving opening. The guide groove has a pair of plate-like facing portions for defining a communicating guide groove, and the width of the guide groove corresponding to the interval between the pair of plate-like facing portions is narrower than the width of the shock transmission pin. When the base frame is lifted at the time of a rear impact, the impact transmission pin moves upward while bending and deforming the plate-like facing portion so as to enlarge the width of the guide groove. Is a framework structure of a vehicle seat characterized in that is absorbed or relaxed.

  According to a second aspect of the present invention, in the framework structure for a vehicle seat according to the first aspect, the pair of plate-like facing portions extend along an inner edge of each plate-like facing portion and the plate of the shock absorbing bracket. It has the flange-shaped guide part formed so that it might protrude in the direction orthogonal to a shape part, It is characterized by the above-mentioned.

  According to a third aspect of the present invention, in the framework structure for a vehicle seat according to the second aspect, a front base portion for receiving a load from the seat frame is further provided at or near the front end portion of the base frame. A shaft is provided, and a front base shaft thereof is coaxially connected to the shock transmission pin, and a first flange located below the shock transmission pin is provided at an inner peripheral edge of the pin receiving opening of the shock absorbing bracket. And the second and third flange-shaped support portions that are located above the shock transmission pins and that are connected to the respective flange-shaped guide portions of the pair of plate-like facing portions. The impact transmission pin is supported at three points in the pin receiving opening by simultaneously contacting the first, second and third flange-shaped support portions.

  According to a fourth aspect of the present invention, in the framework structure for a vehicle seat according to any one of the first to third aspects, the base frame includes the base frame at a boundary position between a front half portion and a rear half portion thereof at the time of a rear collision. A notch for assisting the first half of the base frame to bend upward with respect to the second half of the base frame is provided.

  According to the framework structure of the vehicle seat of claim 1, at the time of a rear collision, the seat portion and the back frame are dragged backward, and at least the front end portion of the base frame is lifted up away from the movable rail, The transmission pin is forcibly moved up in the guide groove of the shock absorbing bracket. As the impact transmission pin moves upward, the impact transmission pin bends and deforms the pair of plate-like opposing portions so as to increase the width of the guide groove, and the bending deformation effectively absorbs or reduces the impact at the time of rear impact. Is done. Since this shock absorption is based on the “bending deformation” of the plate-like facing portion by the impact transmission pin that moves up along the guide groove, the processing accuracy of the individual members that make up the shock absorbing structure and the assembly of those members The accuracy does not excessively affect the shock absorption characteristics of the framework structure, and therefore the shock absorption characteristics can be easily set. Therefore, according to the present invention, the energy absorption stability and reproducibility are superior to conventional shock absorption structures based on frictional contact between metal members or crushing or shearing of metal members, and products with stable shock absorption performance. Can be mass-produced.

  According to the framework structure of the vehicle seat of the second aspect, the pair of plate-like facing portions that define the guide groove of the shock absorbing bracket each have a flange-like guide portion. By the action of these flange-shaped guide portions, the physical deformation of each plate-like facing portion accompanying the upward movement of the impact transmission pin in the rear impact is not an irregular deformation such as crushing or shearing. It is limited to “bending deformation” in which the shape facing portion is bent in a specific direction. Therefore, according to the present invention, the absorption or relaxation action of the rear impact is more stable than before.

  According to the framework structure of the vehicle seat of claim 3, the impact transmission pin is formed on the first, second, and third flange-shaped support portions formed on the inner peripheral edge portion of the pin receiving opening of the shock absorbing bracket. At the same time, three points are supported in the pin accommodating opening. Thanks to this three-point support, the front base shaft that is coaxially connected to the impact transmission pin is also stably supported without any backlash. As a result, the support of the front end of the base frame is stabilized, and the seat frame by the base frame is stabilized. Support is also very stable.

  According to the framework structure of the vehicle seat of the fourth aspect, the base frame has a notch portion that assists in bending the front half of the base frame upward with respect to the rear half of the base frame at the time of rear collision. For this reason, even when there are a plurality of base frames, the upward bending of each base frame at the time of rear-end collision is equalized (that is, the upward movement of the impact transmission pin is equalized) to correspond to each base frame. The load distributed to each shock absorbing bracket can be equalized. The equalization of the load in each shock absorbing bracket further stabilizes the absorption characteristics of the rear impact shock of the frame structure of the vehicle seat.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIGS. 1, 2, and 11, a frame structure 10 for a vehicle seat includes a seat frame 1 constituting a skeleton of a seat cushion, a back frame 2 constituting a skeleton of a seat back, and a seat portion. And a pair of left and right slide rail mechanisms 3 (the right slide rail mechanism 3 is shown in FIGS. 1 and 2) for sliding the back frames 1 and 2 back and forth.

  As shown in FIGS. 3 to 5, each slide rail mechanism 3 includes a lower rail 31 as a fixed rail and an upper rail 32 as a movable rail. The lower rail 31 is fixed on the vehicle body HB. The upper rail 32 can slide in the front-rear direction along the lower rail 31.

  As shown in FIGS. 1 to 5, the frame structure 10 of the vehicle seat further includes a pair of left and right base frames 4 for supporting the seat frame 1. Each base frame 4 is supported by the upper rail 32 of the corresponding slide rail mechanism 3. The base frame 4 has a back wall (bottom wall) 41 and a pair of side walls 42a and 42b erected on both the left and right sides thereof, and the base frame 4 has an open sectional shape that is generally open upward. Due to this cross-sectional structure, a sufficient bending strength is imparted to the base frame 4 as a beam.

  A rear wall 41 in the rear half of the base frame 4 is provided with a mounting hole 43 for rivets (see FIG. 3), and the rear half of the base frame 4 is formed on the upper surface of the rear end of the upper rail 32 through the mounting hole 43. It is fixed by rivets 33. On the other hand, the front half of the base frame 4 is not fixed to the upper rail 32, and is allowed to be separated from the upper surface of the upper rail 32 at the time of rear collision, as shown in FIG. That is, the base frame 4 is provided so that at least a front end portion thereof can be lifted upward away from the upper rail 32 at the time of a rear collision.

  A front base shaft 51 is provided near the front end of the base frame 4 (see FIG. 4). The front base shaft 51 is attached to the base frame 4 so as to bridge the inner and outer side walls 42a, 42b of the base frame 4, and extends horizontally along the width direction (left-right direction) of the seat. As shown in FIG. 1, a front link 52 (height link) is rotatably connected to the front half of the base frame 4 via a front base shaft 51, and the base frame 4 is connected via the front link 52. The front half is connected to a position slightly closer to the front than the center of the seat frame 1. The front base shaft 51 receives a load from the seat frame 1 via the front link 52.

  A rear link 54 is rotatably connected to the rear half of the base frame 4 via a rear base shaft 53, and the rear half of the base frame 4 is connected to the seat frame 1 via the rear link 54. It is connected with the rear end part. In this manner, each base frame 4 supports the seat frame 1 above the front link 52 and the rear link 54.

  As shown in FIGS. 3 to 5, an impact transmission pin 50 that is coaxially connected to the front base shaft 51 is provided in the vicinity of the front end portion of each base frame 4. The impact transmission pin 50 is provided so as to protrude horizontally inward from the inner side wall 42a of each base frame 4.

  Cutout portions 44 are formed in the side walls 42 a and 42 b of the base frame 4 at the boundary positions between the front half and the rear half of each base frame 4. Each notch 44 has a wedge shape in which the lower end is narrow and the upper end is wide, and the lower end of the notch 44 almost reaches the back wall 41. These notches 44 function to assist the front half of the base frame 4 to bend upward with respect to the rear half with the notch 44 as a bending base point in a rear impact.

  As shown in FIG. 1 to FIG. 5, the frame structure 10 of the vehicle seat is also associated with the left and right slide rail mechanisms 3 (or the base frame 4), respectively, and the bracket support 6, the shock absorbing bracket 7 and the load. A receiving bracket 9 is provided. In addition, all the main structural members (1, 2, 3, 4, 6, 7, 9) referred to in the present embodiment are made of metal (for example, steel).

  The bracket support 6 includes a bottom plate portion 61 that is substantially rectangular in plan view and that is long in the front-rear direction, and a plate-like support portion 63 that stands up from one inner side near the front end of the bottom plate portion 61. A rivet mounting hole 62 is formed in the bottom plate portion 61 of the bracket support. A vertically long opening 64 is formed in the plate-like support 63 of the bracket support. Further, a rivet 65 (see FIG. 3) and a rivet 66 (see FIG. 5) are provided on the outer side surface and the inner side surface of the plate-like support portion 63, respectively. The meat portion (67) located at the uppermost end of the plate-like support portion 63 and defining the upper end of the vertically long opening 64 is a first stopper that restricts the upward movement of the impact transmission pin 50 at the time of rear collision. Take the role of 67.

  As shown in FIGS. 3 and 6, the shock absorbing bracket 7 is a member that is supported by being superimposed on the bracket support 6, and has a bottom plate portion 71 that is substantially rectangular in plan view and is long in the front-rear direction. And a plate-like main body portion 73 that stands up from the inner side of the bottom plate portion 71. A rivet mounting hole 72 is formed in the bottom plate portion 71 of the shock absorbing bracket 7. The attachment hole 72 coincides with the attachment hole 62 of the bottom plate portion 61 of the bracket support 6.

  A rivet mounting hole 74 is formed in the plate-like main body 73 of the shock absorbing bracket 7, and this mounting hole 74 coincides with the rivet 65 of the bracket support 6. In the present embodiment, the shock absorbing bracket 7 is closely integrated with the bracket support 6 based on the engagement relationship between the rivet 65 and the rivet mounting hole 74. The integrated bracket support 6 and shock absorbing bracket 7 are connected to the upper surface of the front end portion of the upper rail 32 via the rivet mounting hole 72 of the shock absorbing bracket 7 and the rivet mounting hole 62 of the bracket support 6. It is fixed by a rivet 34. Thus, the plate-like main body 73 of the shock absorbing bracket 7 is erected near the front end of the upper rail 32.

  The plate-like main body portion 73 of the shock absorbing bracket 7 provides a plate-like portion that is deformed by the shock transmission pin 50 at the time of rear collision. Specifically, as shown in FIGS. 6A and 6B, the plate-like main body 73 has a pin accommodating opening 75 that can accommodate the impact transmission pin 50, and is positioned on the opening 75. Thus, a vertically long guide groove 76 communicating with the opening 75 is formed. The guide groove 76 is defined by a pair of plate-like facing portions (front-side plate-like facing portion 77 and rear-side plate-like facing portion 78) that face each other with the guide groove 76 therebetween. Since the inner sides (opposed sides) of the two plate-like facing portions 77 and 78 are substantially parallel to each other, the width of the guide groove 76 is substantially uniform over the entire groove. The groove width corresponding to the distance between the pair of plate-like opposing portions 77 and 78 is narrower than the width dimension of the impact transmission pin 50 (that is, the diameter of the circular cross section of the pin 50).

  In addition, flange-like guide portions 81 and 82 extending along the inner edges are formed on the inner edges of the front and rear plate-like facing portions 77 and 78, respectively. Both of these flange-shaped guide portions 81 and 82 protrude in a direction (inward direction) orthogonal to the plate-like main body portion 73. As will be described later, when the pair of plate-like facing portions 77 and 78 are bent and deformed by the impact transmission pin 50 that moves up in the guide groove 76 at the time of a rear collision, each of the plate-like facing portions 77 and 78 is deformed. It functions as a guide part for limiting the bending direction to one specific direction.

  Furthermore, first, second, and third flange-like support portions 83, 84, and 85 are formed on the inner peripheral edge portion of the pin accommodating opening 75 of the shock absorbing bracket 7. The first flange-shaped support portion 83 is located at the bottom (lowest position) of the pin accommodating opening 75 and supports the impact transmission pin 50 accommodated in the pin accommodating opening 75 from below. The second flange-shaped support portion 84 is located on the upper front side of the pin accommodating opening 75 and is connected to a flange-shaped guide portion 81 corresponding to the front plate-shaped facing portion 77. The third flange-shaped support portion 85 is located on the upper rear side of the pin accommodating opening 75 and is connected to a flange-shaped guide portion 82 corresponding to the rear plate-shaped facing portion 78. As shown in FIG. 7, the impact transmission pin 50 is supported at three points in the pin accommodating opening 75 by simultaneously contacting the first, second, and third flange-like support portions 83 to 85.

  The meat portion (79) positioned at the uppermost end portion of the plate-like main body portion 73 of the shock absorbing bracket 7 and defining the upper end of the vertically long guide groove 76 serves as the second stopper 79. The second stopper 79 cooperates with the first stopper 67 of the bracket support 6 to restrict the upward movement of the impact transmission pin 50 at the time of rear collision.

  As shown in FIGS. 5, 7, and 10, the load receiving bracket 9 has a load receiving portion 91 formed in an arc shape at an upper portion thereof, and a pair of front and rear rivet mounting holes 92. The load receiving bracket 9 is connected and fixed to the inner surface of the plate-like support portion 63 of the bracket support 6 based on the engagement relationship between the rivet mounting hole 92 and the rivet 66. With this connection and fixation, the load receiving portion 91 comes into contact with the lower surface of the distal end portion of the first flange-shaped support portion 83, and the load receiving bracket 9 supports the distal end portion of the flange-shaped support portion 83. In other words, the load receiving bracket 9 connected and fixed to the bracket support 6 physically reinforces the first flange-shaped support portion 83, and the first flange-shaped via the impact transmission pin 50 and the front base shaft 51. The resistance to the load from the seat frame 1 brought to the support portion 83 is improved.

  In the framework structure after the assembly is completed, the bracket support 6 is fixed on the upper rail 32 of the slide rail mechanism 3 as shown in FIG. 4 and FIG. The shock absorbing bracket 7 is fixed on the bottom plate portion 61. Then, the front end portion of the base frame 4 is placed on the shock absorbing bracket 7 in a non-constraining manner.

  Next, the operation and effect of this embodiment will be described.

  At the time of non-rear collision (normal time other than rear collision), the entire base frame 4 is placed on the upper rail 32 (see FIGS. 1 and 4), and the impact transmission pin 50 is provided in the pin receiving opening. 75 is supported at three points by first to third flange-like support portions 83 to 85 (see FIGS. 5A and 7A). The downward load when the occupant sits on the seat is mainly transmitted from the seat frame 1 to the slide rail mechanism 3 via the base frame 4, but a part of the load is applied to the front end portion of the base frame 4. It is also applied to the first flange-like support portion 83 of the shock absorbing bracket 7 via the front base shaft 51 and the shock transmission pin 50.

  At the time of a rear impact, a rear impact is applied to the entire seat to try to tilt the back frame 2 toward the position (the position indicated by the solid line in FIG. 2) retracted from the original support position (the position indicated by the phantom line in FIG. 2). . At this time, as shown in FIG. 2, the seat frame 1 is also tilted so that the front portion is lifted along with the movement of the center of gravity of the occupant and the rear tilt of the back frame 2, and the front half of the base frame 4 is the rear half. On the other hand, it is bent so as to be lifted up with the notch 44 as a base point. Along with this, the impact transmission pin 50 is forcibly moved up in the guide groove 76 of the impact absorbing bracket 7.

  As shown in a series of FIGS. 7, 8, and 9, as the impact transmission pin 50 moves upward, the pair of front and rear plate-like facing portions 77 and 78 expand the distance between them (that is, the width of the guide groove 76). Thus, it is continuously bent and deformed from bottom to top. Such bending deformation absorbs the energy of the rear impact and significantly reduces the impact on the occupant seated on the seat. Even when the impact transmission pin 50 reaches the upper end of the guide groove 76 because the rear impact is excessive beyond the assumption (see FIG. 9), the first stopper 67 and the second stopper are used. Since 79 further restricts the impact transmission pin 50 from moving upward, the front portion of the seat frame 1 cannot be lifted any further.

  According to the present embodiment, the absorption of the rear impact is based on “bending deformation” of the plate-like facing portions 77 and 78 by the impact transmission pin 50 that moves upward along the guide groove 76. For this reason, the processing accuracy of individual members constituting the shock absorbing structure and the assembling accuracy of these members do not excessively affect the shock absorbing characteristics of the frame structure, and therefore the shock absorbing characteristics can be easily set. On the other hand, it is generally difficult to set shock absorbing characteristics in an impact absorbing structure based on frictional contact between metal members or crushing or shearing of metal members. In this respect, the shock absorbing structure of the present embodiment is superior in energy absorption stability and reproducibility than the conventional shock absorbing structure. Therefore, according to the present embodiment, a product with stable shock absorbing performance is mass-produced. It becomes possible.

  According to the present embodiment, the pair of plate-like facing portions 77 and 78 that define the guide groove 76 of the shock absorbing bracket 7 have the flange-like guide portions 81 and 82, respectively. Due to the guide action of the flange-shaped guide portions 81 and 82, the physical deformation of the plate-like facing portions 77 and 78 accompanying the upward movement of the impact transmission pin 50 is not irregular deformation such as crushing or shearing. It is limited to “bending deformation”. Therefore, the absorption or relaxation action of the rear impact in this embodiment is very stable.

  The front base shaft 51 that is coaxially connected to the impact transmission pin 50 is also stably supported without play due to the benefit of the three-point support of the impact transmission pin 50 by the second and third flange-shaped support portions 83 to 85. Therefore, the support of the front end portion of the base frame 4 is stabilized, and the support of the seat frame 1 by the base frame 4 is also extremely stabilized.

  The frame structure of the present embodiment has two left and right base frames 4 corresponding to the left and right slide rail mechanisms 3 respectively. Each base frame 4 is formed with a notch 44 that assists in bending the first half of the base frame upward with respect to the second half of the base frame. Therefore, at the time of a rear collision, any base frame 4 can be bent with the notch 44 as a base point, and as a result, the load distributed to each shock absorbing bracket 7 corresponding to each base frame 4 is also ensured to be equal. It becomes. Such equalization of the load greatly contributes to stabilization of the rear impact impact absorption characteristics of the frame structure.

The side view of the right inner side when seeing the right side of the said structure from the position of the centerline (refer FIG. 11) which bisects the frame structure of the vehicle seat according to one Embodiment into right and left. The side view of the right inner side of the framework structure of FIG. 1 at the time of a rear collision. The disassembled perspective view of the left guide rail and its peripheral mechanism in the framework structure of FIG. The perspective view at the time of the assembly completion of the left side guide rail shown in FIG. 3, and its periphery mechanism. It is the figure which looked at the left side guide rail shown in FIG.3 and FIG.4 and its periphery mechanism from another direction, Comprising: (a) is a disassembled perspective view, (b) is a perspective view at the time of completion of an assembly. (A) And (b) is an expansion perspective view of an impact-absorbing bracket. (A) is an enlarged view of the vicinity of the front end of the right guide rail and its peripheral mechanism, and (b) is a sectional view taken along line XX of (a). (A) is an enlarged view of the vicinity of the front end portion of the right guide rail and its peripheral mechanism, and (b) is a sectional view taken along line YY of (a). (A) is an enlarged view near the front end of the right guide rail and its peripheral mechanism, and (b) is a sectional view taken along line ZZ in (a). The principal part expansion longitudinal cross-sectional view in the 1st flange-shaped support part and its vicinity. The schematic plan view when a vehicle seat is viewed from directly above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Seat part frame 2 ... Back part frame 3 ... Slide rail mechanism 4 ... Base frame 6 ... Bracket support 7 ... Shock absorption bracket 9 ... Load receiving bracket 10 ... Frame structure 31 of vehicle seat ... Lower rail (fixed rail)
32 ... Upper rail (movable rail)
44 ... notch 50 ... shock transmission pin 51 ... front base shaft 53 ... rear base shaft 75 ... pin housing opening 76 ... guide grooves 77, 78 ... a pair of plate-like facing portions (front plate-like facing portion 77, rear side plate) Shaped opposite portion 78)
81, 82 ... flange-like guide part 83 ... first flange-like support part 84 ... second flange-like support part 85 ... third flange-like support part

Claims (4)

A seat frame constituting the skeleton of the seat cushion;
A back frame constituting the skeleton of the seat back;
A frame structure for a vehicle seat comprising a slide rail mechanism having a movable rail slidable along a fixed rail to slide the seat and the back frame back and forth, and the frame structure of the vehicle seat The body further
A base frame supported by the movable rail to support the seat frame;
An impact transmission pin provided at or near the front end of the base frame;
In order to provide a plate-like portion that can be deformed by the impact transmission pin, an impact absorbing bracket erected near the front end portion of the movable rail,
The base frame is provided so that at least a front end portion thereof can be lifted up away from the movable rail at the time of rear collision,
The shock absorbing bracket defines a pin receiving opening formed to be able to receive the shock transmitting pin, and a guide groove located above the pin receiving opening and communicating with the pin receiving opening. The width of the guide groove corresponding to the interval between the pair of plate-like facing portions is narrower than the width dimension of the impact transmission pin,
When the base frame is lifted at the time of a rear impact, the impact transmission pin is moved upward while bending and deforming the plate-like facing portion so as to expand the width of the guide groove, thereby absorbing the impact at the time of the rear impact. A frame structure for a vehicle seat, characterized by being relaxed.   The pair of plate-like facing portions includes flange-shaped guide portions formed so as to extend along the inner edge of each plate-like facing portion and project in a direction orthogonal to the plate-like portion of the shock absorbing bracket. The frame structure of the vehicle seat according to claim 1, wherein the frame structure is provided respectively. A front base shaft for receiving a load from the seat frame is further provided at or near the front end of the base frame, and the front base shaft is coaxially connected to the impact transmission pin.
On the inner peripheral edge of the pin receiving opening of the shock absorbing bracket, there is a first flange-shaped support portion positioned below the shock transmission pin, and the pair of plates positioned above the shock transmission pin and the pair of plates. Second and third flange-shaped support portions formed so as to be connected to the respective flange-shaped guide portions of the shape-facing portion are provided,
The impact transmission pin is supported at three points in the pin accommodating opening by simultaneously contacting the first, second and third flange-shaped support portions.
The framework structure for a vehicle seat according to claim 2.   The base frame is provided with a notch for assisting the front half of the base frame to bend upward with respect to the rear half of the base frame at the boundary position between the front half and the rear half of the base frame at the time of rear collision. The framework structure of a vehicle seat according to any one of claims 1 to 3, wherein

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