Thin Suspension Device for Small Vehicle Seats

Abstract

To provide a thin suspension device of a compact vehicle seat which can be stored in a restricted space.SOLUTION: A thin suspension device has: a lower frame installed on a floor surface side of a vehicle; an upper frame that is arranged above the lower frame and is provided integrally with the lower part of the frame constituting a backrest of the vehicle seat; a front link and a rear link that are arranged on each of both and left side faces of the lower frame and the upper frame, and constitute a parallel link mechanism for vertically translationally moving the upper frame with respect to the lower frame; a torsion bar having one end and the other end parallel to each other; a mounting member that fixes one end of the torsion bar parallel to a straight line connecting supporting points rotatably supporting one ends of each of the front link, and mounts the one end on the upper frame; and a bracket that is fixed to the other end of the front link, and has a plane slidably supporting the other end of the torsion bar.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a thin suspension device for a seat of a small vehicle such as a small truck, and more particularly to a thin suspension device for a seat of a small vehicle that includes a suspension mechanism without an air spring and further includes a suspension mechanism according to the difference in the weight of passengers.

Background Art

[0002] In order to drive a vehicle comfortably and safely, an air thin suspension device that can set the height of a vehicle seat to a desired position suitable for the body type of a passenger and accurately attenuate and absorb impacts, vibrations, etc. is used for the vehicle seat.

[0003] This air thin suspension device has a function of adjusting and maintaining the vehicle seat at a reference position of a predetermined set height regardless of the weight of the passenger by supplying air from the outside to the air spring or exhausting air from the air spring according to the height change of the vehicle seat (Patent Documents 1 and 2).

[0004] Many air suspension mechanisms using air springs involve a complex device configuration and control operation including an air spring, and require a space to accommodate them.

[0005] A mechanism for raising the vehicle seat by the restoring force of a torsion bar twisted instead of an air spring is also conceivable. However, since the restoring force is large at first, there is a sudden upward movement (a feeling of being pushed up) at first, and the restoring force becomes small as the twist is released.

[0006] Depending on the weight of the person sitting on the seat, for example, in the case of a passenger with a heavy weight, it is desirable to strongly push up the vehicle seat. Conversely, in the case of a passenger with a light weight, it is desirable to weakly push up the vehicle seat. However, the physical properties of the torsion bar itself cannot be changed corresponding to the weight.

Prior Art Documents

Patent Document

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] In a small vehicle such as a mini - truck, it is difficult to secure a space for accommodating the above - mentioned air - thin suspension device. Therefore, a device that can fit into the storage space is required.

[0009] Furthermore, even in a small vehicle, it is necessary to perform a suspension function corresponding to the weight of the passengers.

[0010] Furthermore, the operation of the device must be possible in a limited space.

[0011] In order to solve such problems, an object of the present invention is to provide a thin - type suspension device for a small - vehicle seat that can be stored in a limited space.

[0012] Furthermore, an object of the present invention is to provide a thin - type suspension device for a small - vehicle seat that can cope with various weights of passengers.

[0013] Furthermore, an object of the present invention is to provide a thin - type suspension device for a small - vehicle seat that can be easily operated in a limited space.

Means for Solving the Problems

[0014] The thin - type suspension device for a small - vehicle seat of the present invention that achieves the above object is a lower frame installed on the floor side of the vehicle, and An upper frame that is disposed above the lower frame and is integrally provided at the lower part of the frame that constitutes the backrest of the vehicle seat; A front link and a rear link that are respectively disposed on the left and right side surfaces between the lower frame and the upper frame and constitute a parallel link mechanism for enabling the upper frame to move vertically in parallel with respect to the lower frame (here, one end of each of the front links disposed on the left and right side surfaces is rotatably supported around a support point on the upper frame, the other end of each of the front links is rotatably supported around a support point on the lower frame, one end of each of the rear links disposed on the left and right side surfaces is rotatably supported around a support point on the upper frame, and the other end of each of the rear links is rotatably supported around a support point on the lower frame), A torsion bar having one end and the other end that are parallel to each other; An attachment member that fixes one end of the torsion bar in parallel with a straight line connecting the support points at which one ends of the respective front links are rotatably supported and attaches the torsion bar to the upper frame; A bracket that is fixed to the other end of the front link and has a plane for slidably supporting the other end of the torsion bar; It has.

[0015] When one end of the torsion bar is fixed to the torsion bar, torsion is applied to the other end of the torsion bar so that a rotational force centered on one end of the torsion bar is generated.

[0016] When the other end of the torsion bar applies the rotational force to the bracket, a torque centered on the support point at which the front link is rotatably supported on the upper frame is generated in the front link. As a result, the upper frame rises while translating with respect to the lower frame.

[0017] The attachment member is provided so as to be movable along the upper frame, and when the attachment member is moved, the torque changes.

[0018] The thin suspension device for the small vehicle seat further includes a second torsion bar having one end and the other end parallel to each other, a second attachment member for fixing one end of the second torsion bar, which is arranged symmetrically and without interference with the first torsion bar, parallel to the straight line and attaching it to the upper frame, a second bracket fixed to the upper frame and having a plane for slidably supporting the other end of the second torsion bar, and can further include.

[0019] When one end of the second torsion bar is fixed to the second torsion bar, torsion is applied to the other end of the second torsion bar so that a rotational force centered on one end of the second torsion bar is generated.

[0020] When the other end of the second torsion bar applies the rotational force to the second bracket, a torque is generated about a support point at which the front link is rotatably supported by the upper frame. The thin suspension device for the small vehicle further includes a rod movable along the upper frame, and the attachment member and the second attachment member are fixed to the rod. When the rod moves to move the attachment member and the second attachment member, the torque changes.

[0021] The first torsion bar and the second torsion bar can have the same substantially S-shaped configuration.

[0022] The plane of the bracket and the plane of the second bracket are inclined so that when the rod moves, the other end of the torsion bar can slide on the plane of the bracket and the other end of the second torsion bar can slide on the plane of the second bracket.

[0023] The upper frame and the lower frame may be connected by a tether belt having a length that does not prevent the upper frame from rising due to translational movement thereof.

Advantages of the Invention

[0024] In the thin suspension device for a small vehicle seat according to the present invention, since the force for raising the upper frame with respect to the lower frame is generated by the torsion bar, the mechanism of the thin suspension device is simplified, and it can be installed in the limited space where the small vehicle seat is arranged.

[0025] Furthermore, one end of the torsion bar used in this device is fixed to the attachment member provided on the upper frame, but the other end is slidably supported on the plane of the bracket fixed to the other end of the front link. Therefore, even when the upper frame rises with respect to the lower frame and the rotational force acting on the bracket of the torsion bar decreases, the torque itself is substantially maintained and the upper frame rises smoothly.

[0026] Also, when the attachment member is moved along the upper frame, the torque generated in the front link changes, so that the torque can be set according to the weight of the occupant.

[0027] Furthermore, since the frame constituting the backrest of the vehicle seat and the upper frame are integrally formed, the vehicle seat is further miniaturized and simplified.

[0028] When the upper frame and the lower frame are connected by a tether belt, even when an excessive load such as a collision is received, the load is transmitted to the lower frame, so that deformation of the suspension device is suppressed.

Brief Description of the Drawings

[0029]

Figure 1

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BEST MODE FOR CARRYING OUT THE INVENTION

[0030] The thin suspension device 1 for a small vehicle seat of the present invention is shown in FIGS. 1 and 2. FIG. 1(a) is a perspective view of the thin suspension device in a state where the lower part of the frame 2 constituting the backrest of the vehicle seat is integrally assembled, and FIG. 1(b) is a side view of the device. FIG. 2(a) is a perspective view seen from above the thin suspension device, and FIG. 2(b) is a perspective view seen from below the thin suspension device.

[0031] As shown in FIGS. 1(a), (b), 2(a), and (b), the thin suspension device 1 includes a lower frame 3 attached to the floor surface of the vehicle or a slide rail on the floor surface, and an upper frame 4 disposed above the lower frame 3 and integrally provided at the lower part of the frame constituting the backrest of the vehicle seat (not shown).

[0032] Conventionally, a seat cushion frame has been attached to the upper frame, but in the present invention, since the frame constituting the backrest of the vehicle seat and the upper frame are integrally formed, the vehicle seat is further miniaturized and simplified.

[0033] The lower frame 3 is composed of members with a U-shaped cross-section on the left and right sides (see Figs. 2(a), (b) and Fig. 3). A first rod 5 is rotatably supported about a support point in front of the lower frames. A rear connecting member 6 is fixed behind the lower frames.

[0034] The upper frame 4 is composed of left and right members 7a, 7b with a U-shaped cross-section on the lower side (Fig. 2(b)) and a U-shaped pipe member 8 connecting the front of them. A pipe member 9 is connected between the members 7a, 7b of the upper frame 4, and a face member 10 for supporting a vehicle seat is provided. A connecting member 11 is fixed to the pipe member 8.

[0035] As one of the features of the thin suspension device for a small vehicle seat of the present invention, front links 20a, 20b and rear links 22a, 22b for constituting a parallel link mechanism for enabling the upper frame to move vertically in parallel with respect to the lower frame are provided symmetrically on the left and right of the upper frame and the lower frame.

[0036] One ends of the left and right front links 20a, 20b are rotatably supported about a support point by fixtures 12a, 12b fixed to the back surface of a connecting member 11 fixed to the upper frame 4 as well shown in Figs. 2(b) and 3.

[0037] The other ends of the left and right front links 20a, 20b are fixed to a first rod 5 rotatably attached to the lower frame 3 as well shown in Figs. 2(b) and 8. Since the first rod 5 is rotatably supported about a support point by the lower frame 3, the front links 20a, 20b are rotatably supported about that support point.

[0038] One ends of the left and right rear links 22a, 22b are rotatably supported about a support point by the upper frame 4 as well shown in Figs. 2(a) and 5 to 9.

[0039] The other ends of the left and right rear links 22a and 22b are rotatably supported about a support point on the lower frame 3 as well shown in FIGS. 2(a), 5 to 9.

[0040] Since these links are arranged inside the upper frame, the suspension device can be made compact.

[0041] A thin suspension device 101 of another embodiment of the seat for a small vehicle according to the present invention is shown in FIG. 14. FIG. 14(a) is a right side view of the thin suspension device of another embodiment, FIG. 14(b) is a right front perspective view of the thin suspension device of another embodiment, and FIG. 14(c) is a right front perspective view of the thin suspension device of another embodiment. The configuration of this thin suspension device 101 is basically the same as that of the thin suspension device 1, and a detailed description thereof will be omitted.

[0042] Also in this embodiment, the rear links 122a and 122b are rotatably supported by the upper frame 104 and the lower frame 103, but it is different from the thin suspension device 1 in that the end portions of the rear connecting member 106 are fixed to the rear links 122a and 122b.

[0043] As shown in FIG. 8, a parallel link mechanism is formed by the front link 20a (20b) and the rear link 22a (22b), and as the two links rotate, the upper frame 4 can translate vertically with respect to the lower frame 3.

[0044] A shock absorber 13 is attached between the first rod 5 and the rear connecting member 6 (FIGS. 2(b), 4, 5) in order to prevent the upper frame 4 from moving up and down abruptly with respect to the lower frame 3.

[0045] In another embodiment (FIG. 14), without providing a shock absorber, it is for adjusting sudden vertical movement. A plurality of U-shaped (or inverted U-shaped) damper rubbers DR are downwardly attached to the upper frame 4, and a plurality of them are upwardly attached to the lower frame 3 (preferably at the four corners). These damper rubbers DR are compressed near the lowest position of the upper frame. Also, as described below, a resin or metal cap covering the other end of the torsion bar, or a roller or bearing provided at the other end generates sliding resistance. These actions alleviate the sudden descent of the upper frame.

[0046] As described above, since the frame constituting the backrest of the vehicle seat is integrally provided on the upper frame, the seat belt buckle B is attached to the upper frame 104.

[0047] Furthermore, the upper frame and the lower frame are connected by a tether belt TB. The tether belt is of a length that does not prevent the upward movement due to the translational movement of the upper frame.

[0048] When the vehicle receives an excessive load such as a collision, for example, the load is transmitted to the upper frame through a seat belt (not shown) and the seat belt buckle B. However, since the upper frame 4 and the lower frame 3 are connected by the tether belt TB, the impact is also transmitted to the lower frame 3. As a result, the deformation of the suspension device is suppressed.

[0049] As another feature of the thin suspension device for a small vehicle seat of the present invention, as described below, a torsion bar is provided, and due to the torque generated in the link based on the torsion of the torsion bar, the upper frame 4 moves up and down with respect to the lower frame 3, but it has a weight adjustment mechanism that can change the torque corresponding to the weight of the occupant. Furthermore, it has a configuration in which the torque does not substantially vary regardless of the up and down movement of the upper frame.

[0050] The configuration of the weight adjustment mechanism 30 will be described. The cross-sectional view of the weight adjustment mechanism 30 is shown in FIG. 5, and it has a frame 33 having a front wall portion 31 and a rear wall portion 31' facing each other in parallel, and side wall portions 32, 32' also facing each other in parallel. The frame member 33 is fixed to the front and back sides of the pipe member 8 and the connecting member 11.

[0051] Corresponding holes are provided in the front wall portion 31 and the rear wall portion 31', and recesses of the same shape are formed in both side wall portions 32, 32'. Thread holes are formed in a rod 35 disposed parallel to a straight line connecting the support points of one end of the aforementioned front link in these recesses (see FIG. 15(a)). A weight adjustment shaft 36 having a thread formed thereon that is screwed with the thread of this thread hole is arranged to pass through the hole of the front wall portion 31, through the thread hole of the rod 35, and further through the hole of the rear wall portion 31'. As shown in FIGS. 2 to 5, a weight adjustment dial 36' is fixed to the outer end portion of the weight adjustment shaft 36.

[0052] The weight adjustment shaft 36 idles (does not advance or retreat in its axial direction) with respect to the holes of the front wall portion 31 and the rear wall portion 31'. However, since the thread of the weight adjustment shaft 36 is screwed with the thread hole of the rod 35, when the weight adjustment dial 36' is rotated, the rod 35 positioned within the recess advances and retreats according to the weight adjustment dial rotation direction. By the advancement and retreat of this rod 35, as described below, the torque can be changed corresponding to the weight of the passenger.

[0053] Mounting members 37a, 37b for fixing and attaching one end of a torsion bar described below are fixed to the rod 35 (see FIGS. 2(b), 6, 7, 15(a)). The weight adjustment shaft 36 is screwed into the provided thread hole of the rod 35 (see FIG. 15(a)).

[0054] In another embodiment (Fig. 15(b)), a bracket 35b is provided approximately at the center of the rod 35, a nut 35n is fixed in a hole provided in the bracket 35b, and the nut 35n is screwed with the weight adjustment shaft 36. In this way, by interposing the bracket 35b, the arrangement position of the weight adjustment shaft 36 can be changed.

[0055] On the first rod 5 (rotatably supported about a support point on the lower frame 3) to which the other end of the front link is fixed, brackets 40a and 40b for slidably supporting the other end of the torsion bar described below are also fixed. Therefore, since the brackets 40a and 40b are fixed to the front link, when the front link rotates, the brackets also rotate via the first rod 5.

[0056] Each of the brackets 40a (40b) is composed of substantially triangular facing side walls 41a, 41a' (41b, 41b') and a flat portion 42a (42b) connecting the bottoms thereof, and on the flat portions 42a and 42b, the other end of the torsion bar is slidable.

[0057] In the illustrated embodiment, the torsion bars constituting the present invention are two and are symmetrically arranged so as not to interfere with each other, and are attached to the above-described attachment members and brackets as follows.

[0058] The torsion bar has an S shape, is long in the center, and is short at both ends and parallel to each other. The torsion bar is twisted so that when one end is fixed and a rotational force about that end is generated at the other end (that is, when one end is fixed and the other end is rotated (twisted) about that end, a rotational force (about one end) is generated by the restoring force of the torsion bar so that the other end tries to return to its original position). Due to this rotational force (restoring force), the upper frame can be raised with respect to the lower frame.

[0059] As shown in FIGS. 2(b) and 15(a), one end R1 of one torsion bar T1 is fixed to the mounting member 37a of the rod 35 so as to be parallel to the above-mentioned straight line. On the other hand, the other end R2 of the torsion bar T1 (which is parallel to the one end R1) is simply placed on the flat portion 42a of the bracket 40a fixed to the first rod 5 and is slidable (see FIGS. 3 and 7. However, in this figure, the arrangement of the other end of the other torsion bar on the flat portion 42b of the bracket 40b is shown).

[0060] One end R3 of the other torsion bar T2 is fixed to the mounting member 37b (see FIG. 15(a)) fixed at a position shifted so that the two torsion bars do not interfere with each other. On the other hand, the other end R4 of the torsion bar T2 (which is parallel to the one end R3) is simply placed on the flat portion 42b of the bracket 40b fixed to the first rod 5 and is slidable (see FIG. 7).

[0061] Resin or metal caps are put on the other ends R2 and R4 of the torsion bars T1 and T2 so that smooth sliding is possible. Instead of the caps, rollers or bearings may be provided.

[0062] When the other end of the torsion bar is arranged on the bracket, as described above, torsion has already been applied, and the other end can apply a rotational force (restoring force) to the flat portion of the bracket.

[0063] In the illustrated embodiment, two torsion bars are attached, but even one can be implemented. Also, in addition to the S shape, a U shape is also possible.

[0064] Furthermore, although one end and the other end of the torsion bar are parallel, as long as one end is fixed, the other end is slidable, and the rotational force can act on the bracket, it is not necessary to be strictly parallel.

[0065] Since such a torsion bar is substantially planar, it can be arranged within the upper frame and the lower frame, and the suspension device can be made thinner.

[0066] Next, with reference to FIGS. 10 to 13, the torque generated in the link will be described, and the weight adjuster will be used to adjust the magnitude of the torque and explain the weight adjustment corresponding to the weight of the passenger, and it will be explained that the torque generated in the link hardly varies even when the upper frame rises.

[0067] FIGS. 10 to 13 illustrate the front portions of the upper frame and the lower frame including the weight adjustment mechanism for the sake of simplification of the explanation. As described above, at the other ends R2 and R4 of the torsion bars T1 and T2 to which torsion is applied, a force acts on the point of the flat portion with which the other ends are in contact based on the rotational force (restoring force).

[0068] Let the component of this force in the direction perpendicular to the flat portion 42 be F, and let the distance from the support point where one end of the front links 20a and 20b is rotatably supported to the perpendicular line along the direction of the force F be L.

[0069] One ends R1 and R3 of the torsion bars T1 and T2 are fixed to the rod 35, and since the position of the rod 35 is constant with respect to the upper link 4, the torque generated in the front links can be expressed as F·L about the support point where one end of the front links 20 and 20 is supported.

[0070] As shown in FIG. 8, since a parallel link mechanism is formed by the front links 20a (20b) and the rear links 22a (22b), based on the torque F·L, both links rotate, and the upper frame 4 can move vertically in parallel with respect to the lower frame 3.

[0071] Figure 10 shows the weight adjustment mechanism assuming a heavy passenger weight (130 kg in the figure). Lock the upper frame so that the upper frame is in the lowest position. Next, rotate the weight adjustment dial in one direction. As it rotates, the weight adjustment shaft 36’ rotates idly without moving forward or backward, but the rod 35 that meshes with the weight adjustment shaft 36 moves backward. Rotate the weight adjustment dial 36’ until the rod 35 is in the most rearward position. The attachment members 37a, 37b fixed to the rod 35 also move backward as they are.

[0072] One end of each of the torsion bars T1, T2 whose other ends are fixed to the attachment members 37a, 37b slides on the flat portions 42a, 42b of the brackets 40a, 40b and moves backward. The brackets 40a, 40b are fixed to the first rod 5 such that the flat surfaces are inclined (inclined upward to the right in Figure 10) so that the ends of the torsion bars can move smoothly.

[0073] Figure 11 shows the weight adjustment mechanism assuming a light passenger weight (50 kg in the figure). Also in this case, lock the upper frame so that the upper frame is in the lowest position. Next, reverse the rotation of the weight adjustment dial. As it rotates, the weight adjustment shaft 36’ rotates idly, but the rod 35 that meshes with the weight adjustment shaft 36 moves forward. The attachment members 37a, 37b fixed to the rod 35 also move forward as they are. One end of each of the torsion bars T1, T2 whose other ends are fixed to the attachment members 37a, 37b slides on the flat portions 42a, 42b of the brackets 40a, 40b and moves forward.

[0074] The other ends R2, R4 move forward, and the distance L from the support point to the perpendicular dropped to the straight line along the direction of the force F acting on the flat portion becomes smaller, and the torque F·L generated in the front link is smaller than in the case of 130 Kg.

[0075] Thus, without changing the rotational force (restoring force) of the torsion bar (i.e., the physical properties of the torsion bar itself), by rotating the weight adjustment dial to change the moving position of the rod 35, that is, changing it to the position at the other end of the torsion bar, the torque for raising the upper frame can be adjusted according to the weight of the occupant.

[0076] In this way, the torque is adjusted by the weight adjustment mechanism to cope with changes in the weight of the occupant. Since the suspension device raises the seat sheet based on the torsion bar, the function of the suspension device can be specified by the "spring constant as a suspension". Then, the weight adjustment mechanism can change the "spring constant as a suspension" to be low for a light person and high for a heavy person.

[0077] Since the rotation of the weight adjustment dial can be easily performed in a narrow space, the suspension device can be operated in a limited space.

[0078] Since this weight adjustment mechanism is located between the upper frame and the lower frame, this suspension device becomes thin and can therefore be housed in a limited space.

[0079] When the lock of the locked upper frame shown in FIGS. 10 and 11 is released, as shown in FIGS. 12 and 13, based on the above-described torque, the front links 20a, 20b (since the rear links 22a, 22b form parallel links with the front links, the rear links are the same) rotate about the support points where the other ends of the front links 20a, 20b (the rear links are the same) are supported by the lower frame, and the upper frame 4 moves in a translational motion upward.

[0080] When the front link rotates, the first rod 5, to the other end of which the front link is fixed, also rotates. The brackets 40a and 40b fixed to the first rod 5 also rotate. Since one ends R1 and R3 of the torsion bars T1 and T2 are fixed, the other ends R2 and R4 move backward (rearward) while sliding along the flat portions 41’a and 41’b of the brackets. At this time, the twists of the torsion bars T1 and T2 are released. However, the perpendicular line L from the support point to the straight line passing through the force F becomes longer, and the torque ·L does not substantially change.

[0081] If the torque F·L does not substantially change, the force pushing up the upper frame is maintained, and the seat seat can be smoothly raised to a predetermined height.

[0082] To return the upper frame 4 (104) to its original position, press the upper frame from above against the twist resistance of the torsion bar. At this time, the other ends R2 and R4 of the torsion bar move forward (frontward) while sliding along the flat portions 41’a and 41b’. Lock when the upper frame is at the lowest position.

[0083] The small vehicle seat to which the thin suspension device of the present invention is assembled can be used for passengers with a wide range of weights from 50 kg to 130 kg.

[0084] As described above, the embodiments and examples of the present invention have been described. However, these embodiments and examples are presented as examples and are not intended to limit the scope of the invention. These novel embodiments described above can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the present invention. These embodiments and their examples are included in the scope and gist of the invention and are included in the invention described in the claims.

Explanation of Signs

[0085] 1 Thin suspension device 2 Frame 3(103) Lower frame 4(104) Upper Frame 5 First Rod 6(106) Rear Connecting Member 7a(107a), 7b(107b) Members 8 U-shaped Pipe Member 9 Pipe Member 10 Face Member 11 Connecting Member 12 Fixture 20a, 20b Front Links 22a(122a), 22b(122b) Rear Links 30 Weight Adjustment Mechanism 31 Front Wall Portion 31’ Rear Wall Portion 32, 32’ Side Wall Portions 33 Frame Member 35(35’) Rod 35b Bracket 35n Nut 36 Weight Adjustment Shaft 36’ Weight Adjustment Dial 37a, 37b Mounting Members 40a, 40b Brackets 41a, 41b Side Walls 42a, 42b Flat Portions T1, T2 Torsion Bars R1, R3 One End R2, R4 The Other End B Seat Belt Buckle TB Tether Belt DR Damper Rubber

Claims

1. A thin suspension device for a small vehicle seat, comprising: a lower frame installed on the floor side of the vehicle; an upper frame disposed above the lower frame and provided under the vehicle seat of the vehicle; front links and rear links respectively disposed on the left and right side surfaces of the lower frame and the upper frame, and constituting a parallel link mechanism for enabling the upper frame to move vertically in translation with respect to the lower frame; Here, one end of each of the front links disposed on the left and right side surfaces is rotatably supported about a support point on the upper frame, and the other end of each of the front links is rotatably supported about a support point on the lower frame; one end of each of the rear links disposed on the left and right side surfaces is rotatably supported about a support point on the upper frame, and the other end of each of the rear links is rotatably supported about a support point on the lower frame; a torsion bar having one end and the other end parallel to each other; an attachment member for fixing one end of the torsion bar parallel to a straight line connecting the support points at which one ends of the respective front links are rotatably supported, and attaching the same to the upper frame; a bracket fixed to the other end of the front link and having a plane for slidably supporting the other end of the torsion bar; and when one end of the torsion bar is fixed, torsion is applied to the other end of the torsion bar so that a rotational force about the one end of the torsion bar is generated; when the other end of the torsion bar applies the rotational force to the bracket, a torque is generated in the front link about the support point at which the front link is rotatably supported on the upper frame, and as a result, the upper frame rises while translating with respect to the lower frame; the attachment member is provided so as to be movable along the upper frame, and when the attachment member is moved, the torque changes; A thin suspension device for a vehicle seat, characterized in that.

2. a second torsion bar having one end and the other end parallel to each other; a second attachment member for fixing one end of the second torsion bar parallel to the straight line symmetrically and non-interferingly with respect to the torsion bar, and attaching the same to the upper frame; A second bracket fixed to the upper frame and having a plane that slidably supports the other end of the second torsion bar; further comprising; When one end of the second torsion bar is fixed to the second torsion bar, torsion is applied to the other end of the second torsion bar so that a rotational force centered on one end of the second torsion bar is generated. When the other end of the second torsion bar applies the rotational force to the second bracket, a torque is generated about a support point at which the front link is rotatably supported by the upper frame. The thin suspension device for a small vehicle seat according to claim 1, characterized in that.

3. Furthermore, it includes a rod movable along the upper frame, The attachment member and the second attachment member are fixed to the rod, When the attachment member and the second attachment member are moved by the movement of the rod, the torque changes. The thin suspension device for a small vehicle seat according to claim 2, characterized in that.

4. The torsion bar and the second torsion bar have the same substantially S-shaped configuration. The thin suspension device for a small vehicle seat according to claim 3, characterized in that.

5. By the movement of the rod, the other end of the torsion bar slides on the plane of the bracket, and the other end of the second torsion bar can slide on the plane of the second bracket. The plane of the second bracket is inclined. The thin suspension device for a small vehicle seat according to claim 3, characterized in that.

6. The upper frame and the lower frame are connected by a tether belt, The tether belt has a length that does not prevent the upward movement due to the translational movement of the upper frame. The thin suspension device for a small vehicle seat according to claim 1.

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