Suspension device for vehicle seat

Abstract

A suspension device comprising: a shock absorber including a cylinder part and a piston part that is provided so as to be capable of sliding with respect to the cylinder portion and can adjust damping force by being rotated in a circumferential direction, in which one among the cylinder portion and the piston portion is attached to an upper frame side and the other is attached to a lower frame side; a height position change detection part that detects a change in a height position of the upper frame; and a piston part rotation part that rotates the piston part provided to the shock absorber in accordance with the detection of a change in the height position of the upper frame by the height position change detection part.

Description

Suspension device for vehicle seat 【0001】 The present invention relates to a suspension device for a vehicle seat. 【0002】 Conventionally, a suspension device for a vehicle has been proposed (for example, Patent Document 1). In Patent Document 1, a shock absorber that accurately attenuates and absorbs impacts, vibrations, etc. may be mounted. The shock absorber can be provided with a hardness adjustment mechanism that can be adjusted to a hardness according to the preference of the passenger. 【0003】 Japanese Unexamined Patent Application Publication No. 2014-162397 【0004】 However, since the hardness of the conventional shock absorber is selected by the operation of the passenger, if there is no operation by the passenger, the hardness selected at that time is maintained. For this reason, for example, if a soft state is selected as the hardness of the shock absorber, when the vehicle approaches a large step, so-called bottoming may occur. Also, it is assumed that the line of sight of the passenger and the movement of the vehicle are different, and the passenger may feel discomfort. Also, the movement of the pedals, steering wheel, and seat may become relatively large and interfere with the driving operation. There are passengers who dislike such phenomena and fix the hardness of the shock absorber to a hard state, and there are cases where the preferred hardness cannot be set. 【0005】 Thus, if the change in the hardness of the shock absorber is left to the operation of the passenger, it is assumed that the effect of the suspension device cannot be fully enjoyed. 【0006】 Therefore, an object of the present invention is to provide a suspension device for a vehicle seat in which the hardness of a shock absorber is automatically adjusted in accordance with the operation of the suspension device. 【0007】The above objective is to provide a lower frame installed on the floor side of the vehicle, an upper frame positioned above the lower frame and provided below the vehicle seat of the vehicle, an X-shaped intersecting member positioned on the left and right sides between the lower frame and the upper frame, connected to the lower frame and the upper frame to support the upper frame so as to be able to move up and down, a pair of X links pivotally attached to a shaft body connecting the intersecting portions of the X shape, an elastic support mechanism provided between the lower frame and the upper frame to elastically support the upper frame relative to the lower frame, and a mechanism to move the upper frame up and down relative to the upper frame This is achieved by a suspension device for a vehicle seat, comprising: a vertical movement mechanism; a shock absorber having a cylinder portion and a piston portion slidably mounted relative to the cylinder portion and capable of adjusting damping force by rotation in the circumferential direction, with one of the cylinder portion and the piston portion attached to the upper frame side and the other attached to the lower frame side; a height position change detection unit that detects changes in the height position of the upper frame; and a piston portion rotation unit that rotates the piston portion of the shock absorber in response to the height position change detection unit detecting changes in the height position of the upper frame. 【0008】 According to the above configuration, for example, when a passenger is seated in a vehicle seat, and the vehicle approaches a step, causing the vehicle seat to drop significantly, the height position change detection unit detects the drop in the vehicle seat, and the piston rotation unit rotates the piston portion of the shock absorber accordingly. This automatically adjusts the damping force of the shock absorber. 【0009】Furthermore, the height position change detection unit comprises a first packing provided on the base end side, an air introduction section provided on the tip side of the first packing, and an air discharge section provided on the tip side of the air introduction section, and a valve cylinder attached to the lower frame side, and a valve piston provided slidably within the valve cylinder and equipped with a second packing that is movable between a region between the air introduction section and the air discharge section within the valve cylinder and a region on the tip side of the air discharge section, and the piston portion rotation section comprises an air chamber into which air discharged from the air discharge section is introduced, a pressing pin member provided so as to be able to move in and out of the air chamber and which moves in the protruding direction when air is introduced into the air chamber, and a transmission piece that engages with the piston portion of the shock absorber and rotates the piston portion so as to increase the damping force of the shock absorber when pressed by the pressing pin member, and is biased by an elastic member in a direction that decreases the damping force of the shock absorber. This allows the damping force of the shock absorber to be increased in response to changes in the height of the vehicle seat, and to be restored to its original state when the height of the vehicle seat returns to its original position. 【0010】Furthermore, the elastic support mechanism and the vertical movement mechanism are air springs that move the upper frame up and down by pressure changes caused by the supply of compressed air from a supply source and exhaust to the outside, and include an air supply valve that opens and closes an air supply pipe to the air spring and an exhaust valve that opens and closes an exhaust pipe from the air spring, an air supply / exhaust valve body provided on one link member that forms one of the left or right X links, an air supply control cam provided on the one link member that controls the opening and closing of the air supply valve, an exhaust control cam that controls the opening and closing of the exhaust valve, a cam member pivotally mounted on the shaft and stretched on the other link member that intersects with the one link member and rotates together with the other link member, an arm member pivotally mounted on the shaft so as to be rotatable together with the cam member and rotating the air supply control cam or the exhaust control cam in accordance with the direction of rotation of the X link to open and close the air supply valve or the exhaust valve, and a first wire member connected to the cam member that is pulled or fed out The system includes a reference height position changing mechanism which, by rotating the arm member through the cam member, rotates the air intake control cam or the exhaust control cam to open and close the air intake valve or the exhaust valve, thereby moving the upper frame upward or downward due to the pressure change of the air spring, and setting a new predetermined position as the reference height, wherein the height position change detection unit is attached to the shaft body connecting the X-shaped intersection portions of the X-link and includes a slide case member that is slidably provided with respect to the valve cylinder, the valve piston is connected to a second wire member that is linked to the movement of the first wire member, the second wire member is wrapped around a bent portion of the slide case member, and can be configured to follow changes in the positional relationship between the slide case member and the valve cylinder, thereby changing the relative position of the valve piston with respect to the slide case member and maintaining the position of the valve piston with respect to the valve cylinder. As a result, regardless of the reference height of the vehicle seat, the damping force of the shock absorber is automatically adjusted when the height position of the vehicle seat changes. 【0011】Furthermore, the height position change detection unit may be a sensor unit that detects the displacement of a part that is displaced in accordance with the change in the height position of the upper frame, and the piston portion rotation unit may be an actuator that operates in response to the detection signal from the sensor unit and rotates the piston portion. Even in such an configuration, the damping force of the shock absorber is automatically adjusted when the height position of the vehicle seat changes. 【0012】 According to the present invention, a suspension system for a vehicle seat is provided in which the stiffness of the shock absorber is automatically adjusted in accordance with the operation of the suspension system. 【0013】Figure 1(a) is a perspective view of an air suspension system for a vehicle seat, and Figure 1(b) is a plan view of the same air suspension system. Figure 2(a) is a view taken along the line A-A in Figure 1(b) (front view), and Figure 2(b) is a view taken along the line B-B in Figure 1(b). Figure 3(a) is a view taken along the line C-C in Figure 1(b) (front view), and Figure 3(b) is a view taken along the line D-D in Figure 1(b). Figure 4(a) is a view taken along the line E-E in Figure 1(b) (front view), and Figure 4(b) is a view taken along the line F-F in Figure 1(b). Figure 5(a) is a front view of the intake control cam, Figure 5(b) is a perspective view of the intake control cam, Figure 5(c) is a front view of the exhaust control cam, Figure 5(d) is a perspective view of the exhaust control cam, and Figure 5(e) is a front view of the locked state of the intake control cam and the exhaust control cam. Figure 6(a) is a front view of the air valve, Figure 6(b) is a perspective view of the air valve, Figure 6(c) is a front view of the valve plate, Figure 6(d) is a perspective view of the valve plate, Figure 6(e) is a front view of the valve bracket, Figure 6(f) is a perspective view of the valve bracket, Figure 6(g) is a front view of the bracket, and Figure 6(h) is a perspective view of the bracket. Figure 7(a) is a plan view of the air valve, valve plate, valve bracket, and bracket assembled, Figure 7(b) is a front view of the same assembled state, and Figure 7(c) is a perspective view of the same assembled state. Figure 8(a) is a front view of the cam member, Figure 8(b) is a perspective view of the cam member, Figure 8(c) is a front view of the arm member, and Figure 8(d) is a perspective view of the arm member. Figure 9(a) is a plan view of the height position change operation unit, and Figure 9(b) is a front view of the height position change operation unit. Figure 10(a) is a front view of the lowering device, and Figure 10(b) is a front view of the lowering device in operation. Figure 11 is a schematic diagram of the piping for supplying and exhausting air to the air spring. Figure 12 is a schematic diagram of the device illustrating the operation by the reference height position maintenance mechanism, with Figure 12(a) being a schematic diagram of the device when the upper frame is at the reference height position, Figure 12(b) being a schematic diagram of the device when it has been lowered from the reference height position, and Figure 12(c) being a schematic diagram of the device when it has been raised from the reference height position. Figure 13 is a schematic diagram of the device illustrating the operation by the reference height position change mechanism, with Figure 13(a) being a schematic diagram of the device when the upper frame is at the reference height position, Figure 13(b) being a schematic diagram of the device when it has been lowered from the reference height position, and Figure 13(c) being a schematic diagram of the device when it has been raised from the reference height position. Figure 14 is a perspective view showing the damping force adjustment mechanism.Figure 15 shows the piston rotating part and the height position change detection part included in the damping force adjustment mechanism, with Figure 15(a) being a perspective view and Figure 15(b) being a front view. Figure 16 shows the piston rotating part, with Figure 16(a) showing the state where the damping force of the shock absorber is low and Figure 16(b) showing the state where the damping force of the shock absorber is high. Figure 17 shows the main body of the piston rotating part, with Figure 17(a) being a plan view, Figure 17(b) being a front view, and Figure 17(c) being a perspective view. Figure 18 shows the transmission piece included in the piston rotating part, with Figure 18(a) being a plan view and Figure 18(b) being a front view. Figure 19 shows the valve cylinder included in the height position change detection part, with Figure 19(a) being a front view and Figure 19(b) being a plan view. Figure 20 shows the slide case portion included in the height position change detection unit, with Figure 20(a) being a plan view, Figure 20(b) being a front view, and Figure 20(c) being a perspective view. Figure 21(a) is a plan view of the height position change detection unit, and Figure 21(b) is an enlarged view showing the area around the air introduction portion of the valve cylinder in the G-G cross section in Figure 21(a). Figure 22 shows the state of the height position change detection unit, with Figure 22(a) showing the state where the vehicle seat height is adjusted to the lowest position, Figure 22(b) showing the state where the vehicle seat height is adjusted to one level higher, Figure 22(c) showing the state where the vehicle seat height is adjusted to the highest position, and Figure 22(d) showing the state where the vehicle seat height has decreased while the vehicle seat height is adjusted to the highest position. Figure 23 shows other forms of the height position change detection unit, with Figure 23(a) being a schematic diagram showing the configuration of the height position change detection unit, and Figure 23(b) showing the state where there has been a change in height position. Figure 24 shows how the flow control valve mechanism is incorporated between the height position change detection unit and the piston rotation unit of the air suspension device of the second embodiment. Figure 25(a) is a front view of the flow control valve mechanism, and Figure 25(b) is a perspective view of the flow control valve mechanism.Figures 26(a) to 26(c) are cross-sectional views of the flow control valve mechanism along the line H-H in Figure 25(b). Figure 26(a) shows the normal state when the height position change detection unit and the piston part rotation unit are not operating, Figure 26(b) shows the state during intake of air to the piston part rotation unit, and Figure 26(c) shows the state during exhaust from the piston part rotation unit. Figure 27(a) is a view of the first movable valve from the height position change detection unit side, Figure 27(b) is a cross-sectional view of the first movable valve, and Figure 27(c) is a view of the first movable valve from the piston part rotation unit side. Figure 27(d) is a view of the second movable valve from the height position change detection unit side, Figure 27(e) is a cross-sectional view of the second movable valve, and Figure 27(f) is a view of the second movable valve from the piston part rotation unit side. Figure 28 is a graph showing the effect of the flow control valve mechanism on delaying the change in the stiffness of the shock absorber. Figures 29(a) to 29(d) are schematic cross-sectional views showing the operation of the flow control valve mechanism of the third embodiment. Figure 30 is a cross-sectional view of the flow control valve mechanism of the fourth embodiment. Figures 31(a) and 31(b) are explanatory diagrams of the fifth embodiment in which a spring is incorporated into the air chamber of the piston rotating part. Figure 32 is an explanatory diagram of the sixth embodiment in which a buffer member is incorporated into the air introduction wall of the air chamber of the piston rotating part. 【0014】 [First Embodiment] A preferred embodiment of the air suspension device for a vehicle seat according to the present invention will be described below with reference to the attached drawings. First, the configuration of the air suspension device for a vehicle seat will be described mainly with reference to Figures 1 to 11, and then its operation will be described mainly with reference to Figures 12 to 13. In addition, a mechanism for automatically changing the damping force of the shock absorber will be described with reference to Figures 14 to 23. Note that this embodiment is described as an air suspension device because it is equipped with an air spring 18, but if the air spring 18 is not equipped, it will simply be a suspension device. 【0015】<Overall schematic configuration of the air suspension device> As shown in Figures 1 to 11, the air suspension device 11 for a vehicle seat (hereinafter referred to as "air suspension device 11" as appropriate) comprises a lower frame 12 installed on the floor surface of the vehicle or on a slide rail on the floor surface, an upper frame 13 positioned above the lower frame 12 and provided below the vehicle seat (not shown), and a pair of X-links 15a and 15b that intersect in an X shape, positioned on the left and right sides between the lower frame 12 and the upper frame 13, respectively, and connected to the lower frame 12 and the upper frame 13 to support the upper frame 13 so that it can move up and down. 【0016】 The lower frame 12 consists of a frame assembled in a rectangular shape with U-shaped cross-section members on the left and right sides and plate-shaped members at the front and rear, with the opening of the U-shaped cross-section member facing inward into the air suspension device 11. 【0017】 The upper frame 13 consists of a rectangular frame assembled from side frames 13a and 13b, which are members with a U-shaped cross-section on the left and right sides, and cylindrical connecting frames 13c and 13d, which are members that join these side frames and are located on the front and rear sides, respectively. The openings of the side frames 13a and 13b face inward towards the air suspension device 11. 【0018】 The X-links 15a and 15b are positioned on the left and right sides of the air suspension device 11, respectively, between the lower frame 12 and the upper frame 13. The X-link 15a has an X-shape in which the outer link member 16a and the inner link member 16b intersect at approximately the midpoint (see Figures 1 and 4(a)), and similarly, the X-link 15b has an X-shape in which the outer link member 16c and the inner link member 16d intersect at approximately the midpoint (see Figures 1 and 2(a)). The intersecting portions are pivotally mounted on a cylindrical pivot shaft 20. 【0019】As the height of the upper frame 13 changes vertically, the intersection angle of the two link members (16a, 16b) and (16c, 16d) that constitute the X-links 15a and 15b, respectively, which are support members for the upper frame 13, changes clockwise and counterclockwise, respectively. 【0020】 Between the lower frame 12 and the upper frame 13, an air spring 18 is positioned on a lower air spring support member 19a installed on the floor surface. This air spring 18 moves the upper frame 13 up and down by adjusting the pressure through the supply and exhaust of air into the container. An upper air spring support member 19b is attached to the upper part of the air spring 18, which is mounted on the X links 15a and 15b. The pressure fluctuations of the air spring 18 cause the upper air spring support member 19b to move up and down, which in turn rotates the X links 15a and 15b, thereby moving the upper frame 13 up and down. 【0021】 The rear end of the outer link member 16a of X-link 15a and the rear end of the outer link member 16c of X-link 15b are each connected to a connecting shaft 21b pivotally mounted on the upper frame 13, while the front end of the outer link member 16a and the front end of the outer link member 16c are each connected to a connecting shaft 23a pivotally mounted on the lower frame 12 so as to be movable forward and backward (see Figures 1 and 4). 【0022】 Furthermore, the rear end of the inner link member 16b of the X-link 15a and the rear end of the inner link member 16d of the X-link 15b are connected to a connecting shaft 21a pivotally mounted on the lower frame 12, while the front end of the inner link member 16b and the front end of the inner link member 16d are connected to a connecting shaft 23b pivotally mounted on the upper frame 13 so as to be movable forward and backward (see Figures 1 and 4). 【0023】A roller member 25 is attached to the end of the connecting shaft 23a, which is pivotally mounted on the lower frame 12 so as to be movable in the front and rear directions, and to the end of the connecting shaft 23b, which is pivotally mounted on the upper frame 13 so as to be movable in the front and rear directions. The roller member 25 rolls or slides along the travel path of the U-shaped cross-section of the side frame 13a that makes up the lower frame 12 and the upper frame 13, thereby allowing the connecting shafts 23a and 23b to move in the front and rear directions. 【0024】 Alternatively, the connecting shafts 21a and 21b may be pivotally mounted so as to be movable forward and backward, and the connecting shafts 23a and 23b may be pivotally mounted. 【0025】 Furthermore, cylindrical collar members 26 are attached to the upper and lower walls of the side frame 13a, which constitutes the upper frame 13 that serves as the travel path for the roller member 25, by bolts and nuts via plate-shaped reinforcing members 27 positioned on the outer upper part of the travel path, in order to ensure a constant distance between the upper and lower walls (see Figure 4(b)). By maintaining a constant distance between the upper and lower walls, vertical movement of the roller member 25, which rolls along the upper and lower walls of the upper frame 13, can be prevented. In other words, by attaching the collar members 26 between the upper and lower walls of the upper frame 13 and assembling it, the dimensional accuracy between the upper and lower walls can be improved, and deformation of the frame due to welding, etc., can be suppressed, as well as vertical rattle of the roller member 25. The collar members 26 may be made of resin or metal. 【0026】 The reinforcing member 27 is placed on top of the upper frame 13 and is attached with bolts and nuts used to attach the collar member 26 as described above. By providing the plate-shaped reinforcing member 27, deformation of the upper frame can be further suppressed, preventing the roller member from falling off and reducing rattling. 【0027】 Furthermore, shock absorbers 81 are attached to the X-links 15a and 15b to dampen the rotational movement of the X-links 15a and 15b and the vertical movement of the upper frame 13 (see Figure 1(b)). The shock absorbers 81 will be described in detail later. 【0028】As shown in Figure 1(a), a height position change operation unit 32, including a dial member 31, is attached to the side of the upper frame 13 for operating the upper frame's reference height position change mechanism. 【0029】 Furthermore, a lowering operation unit 35, including a lever member 33, is attached to one end of the connecting frame 13c that constitutes the upper frame 13, for operating the height position lowering mechanism that lowers the upper frame 13. 【0030】 Furthermore, a dial member 82, which is part of a damping force adjustment mechanism 80 for adjusting the damping force of the shock absorber 81, is provided at the other end of the connecting frame 13c that constitutes the upper frame 13. The damping force adjustment mechanism 80 will be described in detail later. As shown in Figure 1(a), another dial member is provided between the dial member 31 and the lever member 33. This dial member is a tilt dial for adjusting the angle of the seat portion of the vehicle seat. 【0031】 On the outer link member 16a, one of the two link members constituting the X-link 15a, an air valve 43, which is a supply and exhaust valve body housing an exhaust valve 41 for opening and closing the exhaust pipe to the air spring 18 and an air supply valve 42 for opening and closing the air supply pipe, is provided between the pivot shaft 20 and the connecting shaft 23a, together with a valve plate 61 which is a fastening member, a valve bracket 62 which pivotally mounts the valve plate 61, and a bracket 65 which rotates the valve plate 61 (see Figures 2(b), 3(a), and 6(a) to 6(h)). Details of the attachment of the air valve 43 to the outer link member 16a will be described later. 【0032】 The air valve 43 is provided with an exhaust valve operating rod 51 for operating the exhaust valve 41 and an air intake valve operating rod 52 for operating the air intake valve 42, both of which protrude from the air valve 43 in the direction of the pivot shaft 20. 【0033】Furthermore, the outer link member 16a is pivotally fitted with an exhaust control cam 55 that, by rotation, presses the exhaust valve operating rod 51 to open the exhaust valve 41, and an air intake control cam 56 that, by rotation, presses the air intake valve operating rod 52 to open the air intake valve 42 (see Figures 2(b) and 3(a)). 【0034】 <Intake control cam, exhaust control cam> The shapes of the exhaust control cam 55 and the intake control cam 56, and their combination will be explained with reference to Figure 5. 【0035】 As shown in Figure 5(a), a front view of the exhaust control cam 55, and Figure 5(b), a perspective view, the exhaust control cam 55 is a plate-shaped member comprising a curved portion 55a into which a roller member located at the tip of an arm member (described later) is pressed and moved, a rotating shaft hole portion 55b into which a rotating shaft body that rotates due to the pressing movement of the roller member is inserted, and a pressing portion 55c that presses the exhaust valve operating rod 51 by rotation to open the exhaust valve 41. 【0036】 As shown in Figure 5(c), a front view of the air intake control cam 56, and Figure 5(d), a perspective view, the air intake control cam 56, like the exhaust control cam 55, is a plate-shaped member equipped with a curved portion 56a, a pivot shaft hole portion 56b, and a pressing portion 56c. 【0037】 As shown in Figure 5(e), the exhaust control cam 55 and the intake control cam 56 are locked together by overlapping their pivot shaft holes 55b and 56b to allow insertion of the pivot shaft (see Figure 3(a)). When they are integrated, a recess 58 is formed between the curved portion 55a of the exhaust control cam 55 and the curved portion 56a of the intake control cam 56, which serves as a gap between the two cams. As will be described later, when the roller member located at the tip of the arm member is in a neutral position, which is the reference height position, where it does not act on either the exhaust control cam 55 or the intake control cam 56, the roller member is located in this recess 58. 【0038】As shown in Figure 5(e), the exhaust control cam 55 and the intake control cam 56 form a single cam and act on the exhaust valve operating rod 51 or the intake valve operating rod 52, respectively, depending on the direction of rotation, as will be described later (see Figure 3(a)). The relative position of the exhaust control cam 55 and the intake control cam 56 can be adjusted by loosening the locking between them. This is to adjust the timing with the rotation of the X links 15a and 15b, as will be described later, in order to switch between exhaust and intake. 【0039】 <Air Valve> The attachment of the air valve 43 to the outer link member 16a will be explained with reference to Figures 3(a) and 3(b). The attachment parts used to attach the air valve 43 to the outer link member 16a will be explained with reference to Figures 6 and 7. 【0040】 As shown in Figure 6(a), a front view of the air valve 43, and Figure 6(b), a perspective view, the exhaust valve operating rod 51 is fixed to the valve plate 61 so that it is located at the top and the intake valve operating rod 52 is located at the bottom (see Figures 7(b) and 7(c)). 【0041】 As shown in Figure 6(b), a front view, and Figure 6(d), a perspective view, the valve plate 61 is a plate-shaped member to which the air valve 43 is fixed, and is pivotally mounted to the valve bracket 62. A pivot shaft portion 63a (see Figure 2(b)) fixed to the valve bracket 62 is provided in the pivot shaft hole portion 61a, and the valve plate 61 is rotatable relative to this pivot shaft portion 63a. 【0042】 The valve plate 61 has a valve pin hole 61b into which a valve pin 64 (shown by a dashed line) is inserted to restrict the rotation (see Figure 6(a)), and a wall portion 61c is also formed to restrict the rotation of the bracket 65, which will be described later. 【0043】The valve bracket 62 fixed to the outer link member 16a is formed such that wall portions 62a and 62b against which a valve pin 64 attached to the valve plate 61 abuts are opposed to each other with a predetermined interval therebetween in order to limit the rotation range of the valve plate 61, as shown in FIG. 6(e) which is a front view thereof and FIG. 6(f) which is a perspective view thereof. Further, a spring 66a which is a tension spring is hooked between a hole portion 61d of the valve plate 61 and a protrusion portion 62c of the valve bracket 62 (see FIG. 2(b)), and the valve pin 64 abuts against the wall portion 62b of the valve bracket 62 by the elastic force of the spring 66a, thereby restricting the rotation of the valve plate 61. 【0044】 An axial pin member 62d is further fixed to the valve bracket 62 so as to be positioned in a recess 58 between the exhaust control cam 55 and the intake control cam 56, and restricts the rotation of the exhaust control cam 55 and the intake control cam 56 as will be described later (see FIG. 3(a)). 【0045】 The bracket 65 is a bent plate-like member as shown in FIG. 6(g) which is a front view thereof and FIG. 6(h) which is a perspective view thereof, and has a rotation shaft hole portion 65a for inserting a rotation shaft portion 63b (see FIG. 2(b)) at a substantially central portion, a hole portion 65b for hooking a spring 66b which is a tension spring, and a protrusion portion 65c for hooking one end of a spring 66c (see FIGS. 2(b) and 3(a)). The other end of the spring 66c is connected to a wire member 68a which connects the spring 66 and a lever member 35a of the lowering operation portion 35 (see FIG. 3(a)). 【0046】 A plan view of a state in which the air valve 43, the valve plate 61, the valve bracket 62, and the bracket 65 are assembled is shown in FIG. 7(a), a front view is shown in FIG. 7(b), and a perspective view is shown in FIG. 7(c). 【0047】 The air valve 43 is fixed to the valve plate 61, and the valve plate 61 is pivotally provided at a valve bracket 62 and a rotation shaft portion 63a. As described above, the spring 66a is hooked between the valve plate 61 and the valve bracket 62 and pulled, and the valve pin 64 abuts against the wall portion 62b to prevent rotation. 【0048】 The bracket 65 is pivotally mounted on the valve plate 61 at the pivot shaft portion 63b, and both ends are pulled and tensioned by a spring 66b and a spring 66c, respectively. By operating the lever member 33 of the lowering operation portion 35 to which the wire member 68a connected to the spring 66c is connected and pulling the wire member 68a, the bracket 65 rotates, and further the valve plate 61 rotates, and the exhaust valve operating rod 51 of the air valve 43 is pressed by the pressing portion 55c of the exhaust control cam 55 to open the exhaust valve 41 (see Fig. 3(a), details will be described later). 【0049】 Although it is also possible to connect the wire member 68a directly to the valve plate 61, in this case, variations in the length of the wire member 68a would hinder the lowering operation. Therefore, the bracket 65, springs 66b, and 66c are provided and adjusted. That is, when the wire member 68a is directly connected to the valve plate 61, if the wire member 58a is short, the valve plate 61 will be pulled counterclockwise and the lowering device will be in the ON state at all times. Also, if the wire member 68a is too long, it will sag, causing unnecessary play in the lever portion 35a of the lowering operation portion 35 (see Fig. 10). 【0050】 <Lowering operation portion> The lowering operation portion 35 in the height position lowering mechanism is provided at the end of the connecting frame 13c that constitutes the upper frame 13 (see Fig. 1(a)). Front views of this lowering operation portion 35 are shown in Figs. 10(a) and 10(b). 【0051】Figure 10(a) is a front view of the lowering operation unit 35 when the lowering operation is OFF, with the operating lever member 35a facing downwards. When the lever member 35a is rotated in the R direction so that the tip of the lever member 35a is positioned directly upwards (see Figure 10(b)), the wire member 68a is wound onto the disc-shaped winding unit 35b, and the wire member 68a, via the spring 66c to which it is connected, rotates the bracket 65 counterclockwise, causing it to contact the wall portion 61c of the valve plate 61. The rotation of the bracket 65 causes the bracket 65, via the spring 66b, to rotate the valve plate 61 counterclockwise around the pivot shaft portion 63a. As the valve plate 61 rotates counterclockwise, the air valve 43 provided on the valve plate 61 also rotates counterclockwise, causing the exhaust valve operating rod 51 of the exhaust valve 41 to press against the pressing portion 55c of the exhaust control cam. However, the exhaust control cam 55 is prevented from rotating counterclockwise by the pin member 62d, so the exhaust valve operating rod 51 is pressed. As a result, the exhaust valve 41 opens, the pressure of the air spring 18 decreases, and the lowering device is turned ON, causing the upper frame 13 to descend. 【0052】 As the upper frame 13 descends, the arm member 72 rotates clockwise, and even if the roller member 72a at the tip of the arm member 72 rotates the air intake control cam 56 counterclockwise, as described above, the air valve 43 rotates counterclockwise, so a predetermined gap is created between the air intake control cam 56 and the air intake valve operating rod 52. As a result, the air intake valve 42 cannot be opened and descends to its lowest point. 【0053】When the lever member 35a shown in Figure 10(b) is rotated in the L direction so that its tip is directly below (see Figure 10(a)), the wire member 68a is fed out toward the bracket 65. This feeding of the wire member 68a causes the valve plate, which had been rotating counterclockwise through the bracket 65, to rotate clockwise so that the valve pin 64 comes into contact with the wall portion 62b of the valve bracket 62. The pressure between the exhaust control cam and the exhaust valve operating rod 51 is released, and the exhaust valve closes. At this time, since it is in a position lower than the reference height position, the roller member 72a of the arm member 72 is in a position to press against the intake control cam 56, so the intake valve 42 opens, and the upper frame 13 rises toward the reference height position due to the increase in pressure of the air spring 18. 【0054】 <Cam Member and Arm Member> The shapes and arrangements of the cam member 71 and the arm member 72 will be described with reference to Figures 2, 3, and 8. 【0055】 A front view of the cam member 71 is shown in Figure 8(a), and a perspective view thereof is shown in Figure 8(b). A front view of the arm member 72 is shown in Figure 8(c), and a perspective view thereof is shown in Figure 8(d). The arrangement of the cam member 71 and the arm member 72 in the suspension device 11 is shown in Figures 2(b), 3(a), and 3(b). 【0056】 The cam member 71 is a member that is rotatably inserted into the pivot shaft 20. A spring 66d of a tension spring attached to the inner link member 16b is hooked into a hole 71a formed at one end, and a wire member 68b (first wire member) that connects to the dial member 31 of the height position change operation unit 32 is hooked into a hole 71b formed at the other end (see Figure 9). The cam member 71 is in a state where tension forces act in opposite directions in the holes 71a and 71b, respectively, and is taut on the inner link member 16b, and rotates at the same angle as the inner link 16b. 【0057】 On the upper frame 13 side of the cam member 71, a curved inclined portion 71c and a wall portion 71d that slopes down toward the pivot shaft 20 side from the end of the inclined portion 71c are formed. 【0058】As shown in Figure 2(b), the plate-shaped member plate 70 is pivotally attached to the outer link member 16a by a pivot shaft 70a, and is biased toward the cam member 71 by, for example, a torsion spring 66f, so that the roller member 70b at the tip of the plate 70 is pressed against the inclined surface 71c. 【0059】 As the upper frame 13 rises, the outer link member 16a rotates counterclockwise, causing the roller member 70b to roll along the inclined surface 71c. When the upper frame 13 reaches a predetermined height, the roller member 70b rolling along the inclined surface 71c falls down the wall portion 71d due to the biasing force of the spring 66f. 【0060】 As shown in Figure 4(a), a plate-shaped gear member 73 that rotates integrally with the plate 70 is provided between the plate 70 and the outer link member 16a. When the roller member 70b falls towards the pivot shaft 20 at the wall portion 71d, the gear member 73 also falls towards the pivot shaft 20, and its gear portion meshes with the gear member 74 provided on the inner link member 16b, thereby restricting further upward movement of the upper frame 13 (height position rise restriction). 【0061】 The arm member 72 shown in Figures 8(c) and 8(d) is structured to rotate the pivot shaft 20 in conjunction with the cam member 71 described above, and a cylindrical roller member 72a is rotatably inserted into the tip of the arm member 72. As the arm member 72 rotates, the roller member 72a rolls while pressing against the curved portion 55a of the exhaust control cam 55 and the curved portion 56a of the intake control cam 56, thereby pressing against the exhaust valve operating rod 51 and the intake valve operating rod 52 of the air valve 43, and opening the exhaust valve 41 and the intake valve 42 (see Figures 3(a) and 11). 【0062】 When the upper frame 13 rises from the reference height position, the outer link member 16a rotates counterclockwise and the inner link member 16b rotates clockwise. As a result, the roller member 72a of the arm member 72 rotates the exhaust control cam 55, pressing the exhaust valve operating rod 51 to open the exhaust valve 41 and return to the reference height position. 【0063】Conversely, when the upper frame 13 descends from the reference height position, the outer link member 16a rotates clockwise and the inner link member 16b rotates counterclockwise. As a result, the roller member 72a of the arm member 72 rotates the air supply control cam 56, pressing the air supply valve operating rod 52 to open the air supply valve 42 and return to the reference height position. 【0064】 When the upper frame 13 is at the reference height position, the roller member 72a is located in the recess 58, which is a neutral position where it does not press against either the exhaust control cam 55 or the intake control cam 56 (see Figure 5(e)). 【0065】 <Height Position Change Operation Unit> As shown in Figure 1(a), a height position change operation unit 32 is provided on the upper frame 13 on the X-link 15b side, which is equipped with a dial member 31 that changes the reference height position of the upper frame 13 by rotational operation. 【0066】 As shown in Figure 9(a), a plan view of the height position change operation unit 32, and Figure 9(b), a front view thereof, the height position change operation unit 32 is structured such that by rotating the dial member 31 in the L direction or the R direction, the wire member 68c is wound onto or unwound onto the bracket 36a fixed to the back side of the dial member 31. The wire member 68c is hooked onto a wire member hooking part 36a1 provided on the bracket 36a. 【0067】 The wire member 68c is connected to the wire member 68b, and by rotating the dial member 31 as described above, the cam member 71 to which the wire member 68b is connected and the arm member 72 which rotates integrally with the cam member 71 are rotated, thereby opening the exhaust valve 41 or the intake valve 42 of the air valve 43 through the rotation of the exhaust control cam 55 or the intake control cam 56, and moving the upper frame 13 up and down. 【0068】As shown in Figures 9(a) and 9(b), a bracket 36a positioned on the back side of the dial member 31 is fixed to the shaft 36b, which is the central axis member of the dial member 31. A gear member 36c positioned further inside the bracket 36a and a gear member 36g biased by a spring 36f inserted into a bolt 36d mesh together, so that the rotation of the dial member 31 is performed in steps by the gear members. The upper frame 13 moves up and down with a height position corresponding to the step of rotation of the dial member 31 as the reference height position, and this height position becomes the new reference height position by the reference height maintenance mechanism. 【0069】 As shown in Figure 9(b), when the dial member 31 is rotated in the L direction, the rotation of the exhaust control cam 55 due to the counterclockwise rotation of the arm member 72, through the winding of the wire members 68c and 68b, opens the exhaust valve 41. When the dial member 31 is rotated in the R direction, the rotation of the intake control cam 56 due to the clockwise rotation of the arm member 72, through the winding of the wire members 68c and 68b, opens the intake valve 42. This controls the pressure of the air spring 18 and moves the upper frame 13 upward or downward, and the height position after the movement becomes the new reference height position due to the operation of the reference height maintenance mechanism. 【0070】 A wire member 68e is hooked onto a wire member hooking portion 36a1 provided on the bracket 36a. A wire member (second wire member) 68d is connected to the wire member 68e. The wire member 68d is connected to a valve piston 95 provided in a height position change detection unit 93 included in the damping force adjustment mechanism 80, which will be described later. 【0071】 <Piping to the air spring> A schematic diagram of the piping for supplying air to the air spring 18 and exhausting air from the air spring 18 is shown in Figure 11. As shown in Figure 11, compressed air from a compressor (not shown) is connected to an air valve 43 via pipe 44a, and the air valve 43 and the air spring 18 are connected via pipe 44b. 【0072】The air spring 18 is a container that expands and contracts vertically on both sides. It expands upward when compressed air flows into the container through pipe 44a, air supply valve 42, and pipe 44b, pushing up the upper air spring support member 19b. It contracts downward when compressed air flows out of the container through pipe 44b and exhaust valve 41, lowering the upper air spring support member 19b. 【0073】 The piping to the air spring 18 in this embodiment has a simple structure consisting of one air valve 43, two pipes 44a and 44b, and four connection points 45a, 45b, 45c, and 45d. Compared to conventional piping, the number of devices, pipes, and connection points are all minimized, which reduces costs and the risk of air leakage. 【0074】 Next, the operation of the air suspension device 11 for vehicle seats according to the present invention will be described mainly with reference to Figures 12 and 13. 【0075】 <Reference Height Position Maintenance Mechanism> Figure 12 is a schematic diagram of the device illustrating the operation by the reference height position maintenance mechanism. Figure 12(a) is a schematic diagram of the device when the upper frame is at the reference height position. Figure 12(b) is a schematic diagram of the device when it has been lowered from the reference height position. Figure 12(c) is a schematic diagram of the device when it has been raised from the reference height position. 【0076】 As shown in Figure 12(a), in the reference height position maintenance mechanism that exhibits an auto-leveling function to maintain the reference height of the vehicle seat, when the upper frame 13 is at the reference height position, the roller member 72a at the tip of the arm member 72 is in a neutral position where it does not press against either the exhaust control cam 55 or the intake control cam 56, and is located in a recess 58 formed between the curved portion 55a of the exhaust control cam 55 and the curved portion 56a of the intake control cam 56 (see Figures 3(a) and 5). 【0077】 Therefore, since neither the exhaust valve nor the intake valve of the air valve 43 is open, the internal pressure of the air spring 18 does not fluctuate. 【0078】Next, as shown in Figure 12(b), when a passenger sits in the vehicle seat (not shown), the upper frame 13, under the load of the passenger, descends from the reference height position to a predetermined height position below. As the upper frame 13 descends, the outer link member 16a rotates counterclockwise around the pivot shaft 20, and the inner link member 16b rotates clockwise. 【0079】 As the link members 16a and 16b rotate as described above, the arm member 72 rotates clockwise, and the exhaust control cam 55 and the intake control cam 56 rotate counterclockwise. As a result, the roller member 72a located at the tip of the arm member 72 rotates clockwise from the recess 58 which is the neutral position, pressing against the curved portion 56a of the intake control cam 56, and causing the intake control cam 56 to rotate counterclockwise around the pivot axis portion 63a (see Figures 3(a) and 5). 【0080】 The counterclockwise rotation of the air intake control cam 56 presses the air intake valve operating rod 52 of the air valve 43, opening the air intake valve 42, so compressed air flows into the air spring 18 and the pressure rises. The air spring 18 raises the air spring upper receiving member 19b, raising the upper frame toward the reference height position. 【0081】 When the upper frame 13 returns to the reference height position, the outer link member 16a rotates clockwise and the inner link member 16b rotates counterclockwise. Consequently, the arm member 72 rotates counterclockwise, the exhaust control cam 55 and the intake control cam 56 rotate clockwise, and when the roller member 72a reaches the recess 58 which is the neutral position, the intake valve 42 closes and the rise of the upper frame 13 stops at the reference height position. 【0082】 Next, as shown in Figure 12(c), the occupant stands up from the vehicle seat (not shown), and the upper frame 13, with the load from the occupant reduced, rises from the reference height position to a predetermined height position due to the reaction force of the air spring 18. As the upper frame 13 rises, the outer link member 16a rotates clockwise around the pivot shaft 20, and the inner link member 16b rotates counterclockwise. 【0083】As link members 16a and 16b rotate as described above, the arm member 72 rotates counterclockwise, and the exhaust control cam 55 and the intake control cam 56 rotate clockwise. As a result, the roller member 72a located at the tip of the arm member 72 rotates counterclockwise from the recess 58 which is the neutral position, pressing against the curved portion 55a of the exhaust control cam 55, and causing the exhaust control cam 55 to rotate clockwise around the pivot axis 63a (see Figures 3(a) and 5). 【0084】 The clockwise rotation of the exhaust control cam 55 presses the exhaust valve operating rod 51 of the air valve 43, opening the exhaust valve 41, so compressed air flows out of the air spring 18 and the pressure decreases (see Figure 3(a)). The air spring 18 lowers the air spring upper receiving member 19b, causing the upper frame to descend toward the reference height position. 【0085】 When the upper frame 13 returns to the reference height position, the outer link member 16a rotates counterclockwise and the inner link member 16b rotates clockwise. Consequently, the arm member 72 rotates clockwise, the exhaust control cam 55 and the intake control cam 56 rotate counterclockwise, and when the roller member 72a reaches the recess 58 which is the neutral position, the exhaust valve 41 closes and the descent of the upper frame 13 stops at the reference height position. 【0086】 In this way, the height-maintaining mechanism works to keep the vehicle seat at its standard height by constantly returning it to the standard height position, even in response to changes in the vehicle seat height caused by changes in load due to the passenger sitting down and standing up. This height-maintaining mechanism can always maintain the standard height regardless of the passenger's weight. 【0087】 <Reference Height Position Change Mechanism> Figure 13 is a schematic diagram of the device illustrating the operation by the reference height position change mechanism. Figure 13(a) is a schematic diagram of the device when the upper frame is at the reference height position, Figure 13(b) is a schematic diagram of the device when it has been lowered from the reference height position, and Figure 13(c) is a schematic diagram of the device when it has been raised from the reference height position. 【0088】As shown in Figure 13(a), when the upper frame 13 is at the reference height position, the roller member 72a located at the tip of the arm member 72 is in a neutral position where it does not press against either the exhaust control cam 55 or the intake control cam 56, and is located in a recess 58 formed between the curved portion 55a of the exhaust control cam 55 and the curved portion 56a of the intake control cam 56 (see Figures 3(a) and 5). 【0089】 The cam member 71, which rotates integrally with the arm member 72, has a hole 71a at one end connected to the spring 66d of a tension spring provided on the inner link member 16b, and is pulled in the direction of the spring 66d, while the hole 71b at the other end is connected to the wire member 68b (see Figure 8). As a result, the cam member 71 is in a state of tension on the inner link member 16b. 【0090】 The wire member 68b, one end of which is connected to the hole 71b, has its other end connected to a wire member 68c that is connected to the height position change operation unit 32, and is pulled or fed out by the rotation of the dial member 31 (see Figure 9). 【0091】 As shown in Figure 9(b), when the dial member 31 is rotated in the L direction, the wire member 68b is wrapped around the bracket 36a and pulled in the direction of the dial member 31. Since the rotation of the dial member 31 is performed in steps, the wire member 68b is pulled by a length corresponding to the step. 【0092】 When the wire member 68b is pulled by the dial member 31, the cam member 71 and the arm member 72 are rotated clockwise, and the roller member 72a at the tip of the arm member 72 moves from the neutral position recess 58 to a position where it presses against the curved portion 56a of the air supply control cam 56. Due to the pressure from the roller member 72a, the air supply control cam 56 rotates counterclockwise, pressing against the air supply valve operating rod 52 of the air valve 43 and opening the air supply valve 42, so that compressed air flows into the air spring 18 and the pressure rises (see Figures 3(a) and 11). The air spring 18 raises the air spring upper receiving member 19b and raises the upper frame 13. 【0093】When the upper frame 13 rises to a height corresponding to the number of steps the dial member 31 has been rotated, the roller member 72a moves away from the position where it presses the air supply control cam 56 and returns to the position of the recess 58, so the air supply to the air spring 18 stops and the rise of the upper frame 13 also stops. The height position of the upper frame 13 at this time becomes the new reference height position obtained by activating the reference height position changing mechanism. 【0094】 Conversely, as shown in Figure 9(b), when the dial member 31 is rotated in the R direction, the wire member 68b is pushed out in the direction of the cam member 71. Since the rotation of the dial member 31 is performed in steps, the wire member 68b is pushed out by a length corresponding to each step. 【0095】 When the wire member 68b is pushed in the direction of the cam member 71, the cam member 71 and the arm member 72 are rotated counterclockwise, and the roller member 72a at the tip of the arm member 72 moves from the recess 58 in the neutral position to a position where it presses against the curved portion 55a of the exhaust control cam 55. Due to the pressure by the roller member 72a, the exhaust control cam 55 rotates clockwise and presses against the exhaust operating rod 51 of the air valve 43, opening the exhaust valve 41, so compressed air flows out from inside the air spring 18 and the pressure decreases. The air spring 18 contracts downward, lowering the air spring upper receiving member 19b and further lowering the upper frame 13. 【0096】 When the upper frame 13 descends to a height corresponding to the number of steps the dial member 31 has been rotated, the roller member 72a moves away from the position that presses the exhaust control cam 55 and returns to the position of the recess 58, so the exhaust from the air spring 18 stops and the descent of the upper frame 13 also stops. The height position of the upper frame 13 at this time becomes the new reference height position obtained by activating the reference height position changing mechanism. 【0097】 Thus, with the reference height position change mechanism, by rotating the dial member 31 of the height position change operation unit 32 in steps, the upper frame 13 can be raised or lowered to a height position corresponding to the number of steps, thereby setting a new reference height position. 【0098】<Damping Force Adjustment Mechanism> Next, the damping force adjustment mechanism 80 will be described with reference to Figures 14 to 23. The damping force adjustment mechanism 80 can adjust the damping force of the shock absorber 81. The damping force adjustment mechanism 80 can perform manual damping force adjustment and automatic damping force adjustment in response to changes in the height position of the vehicle seat. In this embodiment, the damping force adjustment mechanism 80 detects the change in the height position of the vehicle seat and the movement of various parts in response to the change in the height position of the vehicle seat when the height of the vehicle seat changes due to energy input from the outside. Then, by changing the damping force of the shock absorber 81 in response to this detection, seat vibration can be effectively suppressed. 【0099】 First, the installation of the shock absorber 81 to the air suspension system will be described with reference to Figures 15(a) and 15(b). The shock absorber 81 comprises a cylinder portion 81a and a piston portion 81b. The piston portion 81b is slidably mounted relative to the cylinder portion 81a. Furthermore, the damping force can be adjusted by rotating the piston portion 81b in its circumferential direction. The specific configuration for adjusting the damping force by rotating the piston portion 81b is conventionally known, so a detailed explanation will be omitted here. 【0100】 The cylinder portion 81a is fixed to the connecting shaft 23a via a cylinder portion support member 84 which is welded to the connecting shaft 23a. The cylinder portion 81a has a pin hole at its end and is pinned in place by a pin member 84a1 which is inserted through the pin hole 84a provided in the cylinder portion support member 84 (see Figure 15(b)). The cylinder portion support member 84 has a pin-shaped portion 84b which supports the valve cylinder 94, which will be described later. 【0101】 The piston portion 81b is equipped with a piston portion support portion 86 at its end, and this piston portion support portion 86 is attached to the pivot shaft body 20 via a U-shaped bracket 85. 【0102】The bracket 85 is welded to the pivot shaft 20. The bracket 85 has a clamping portion 85a formed by a pair of plate-shaped portions facing each other. A pin hole is provided in the clamping portion 85a. The piston portion support portion 86 is positioned within this clamping portion 85a. The piston portion support portion 86 has a pin hole and is supported by the bracket 85 by a pin member 87 inserted through the pin hole in the clamping portion 85a. A flange portion 89d provided on the main body portion 89 of the piston portion rotation portion 88, which will be described later, is also positioned on the clamping portion 85a. 【0103】 Next, the piston rotating section 88 will be described with reference to Figures 16(a) to 18(b). The piston rotating section 88 comprises a main body 89, a transmission piece 90, a pressing pin member 91, and a rotation drive pin member 92. 【0104】 Referring to Figures 17(a) to 17(c), the main body 89 includes a wire member guide portion 89a, a transmission piece storage portion 89b in which the transmission piece 90 is housed, an air chamber 89c, a pair of flange portions 89d, and a spring latch portion 89e. 【0105】 A wire member 68f is positioned in the wire member guide portion 89a (see Figures 16(a) and 16(b)). One end of the wire member 68f is connected to a wire member 68g. The wire member 68g is hooked onto a wire member hooking portion 83b1 of a rotating member 83b, which is rotatably mounted on a bracket 83a constituting the dial member 82 (see Figure 1(a)). The other end of the wire member 68f is connected to a transmission piece 90 (see Figure 14). The dial member 82 is provided for manually operating the transmission piece 90. By operating the transmission piece 90, the damping force of the shock absorber 81 can be adjusted. In other words, by operating the dial member 82, the damping force adjustment mechanism 80 can manually adjust the damping force of the shock absorber 81. 【0106】Air discharged from an air discharge section 94b provided on a valve cylinder 94 of a height position change detection unit 93, which will be described later, is introduced into the air chamber 89c. A pressing pin member 91 is provided in the air chamber 89c so as to be able to move in and out of the air chamber 89c. The pressing pin member 91 moves in a direction that protrudes as air is introduced into the air chamber 89c. 【0107】 In this way, the piston rotation section 88 operates in conjunction with the height position change detection section 93, enabling the damping force adjustment mechanism 80 to automatically adjust the damping force in response to changes in the height position of the vehicle seat. 【0108】 The pair of flange portions 89d are provided with a pair of plate-like portions facing each other. Each plate-like portion is provided with a pin hole 89d1. The flange portions 89d are arranged within the clamping portion 85a together with the piston portion support portion 86 provided on the piston portion 81b of the shock absorber 81, and are supported by the bracket 85 by a pin member 87. 【0109】 One end of the spring 66g is hooked onto the spring hooking portion 89e. The other end of the spring 66g is hooked onto the transmission piece 90. 【0110】 Referring to Figures 18(a) and 18(b), the transmission piece 90 includes a wire member hooking portion 90a, a pressing wall portion 90b, a spring hooking portion 90c, a pin member insertion portion 90d, and a guide portion 90e. The transmission piece 90 is supported within the transmission piece housing portion 89b of the main body portion 89 so as to be able to move in an arc shape around the piston portion 81b within the transmission piece housing portion 89b. 【0111】 The other end of the wire member 68f is hooked onto the wire member hooking portion 90a. This transmits the rotational movement of the dial member 82 to the transmission piece 90 via the wire member 68f. The wire member 68f is wrapped around the arc-shaped guide portion 90e. This allows the wire member 68f to operate smoothly. 【0112】The pressing pin member 91, which has moved in a direction that causes it to protrude due to the pressure of the air introduced into the air chamber 89c, comes into contact with the pressing wall portion 90b. The transmission piece 90 can move around the piston portion 81b as the pressing wall portion 90b is pressed by the pressing pin member 91. 【0113】 The other end of the spring 66g is hooked onto the spring hook portion 90c. This biases the transmission piece 90 in a direction that reduces the damping force of the shock absorber 81. Note that the spring 66g is just one example of an elastic member, and other elastic members besides coil springs may be used. 【0114】 One end of the rotational drive pin member 92 is inserted into the pin member insertion portion 90d. The other end of the rotational drive pin member 92 is inserted into the piston portion 81b. As a result, the rotational movement of the transmission piece 90 is transmitted to the piston portion 81b, allowing the piston portion 81b to rotate. This results in a change in the damping force of the shock absorber 81. 【0115】 <Height Position Change Detection Unit> Next, the height position change detection unit 93 will be described with reference to Figures 19(a) to 22(e). The height position change detection unit 93 comprises a valve cylinder 94, a valve piston 95, a slide case member 96, and a relay member 97. In this embodiment, the height position change detection unit 93 operates in response to changes in the height position of the upper frame 13. In other words, the height position change detection unit 93 detects changes in the height position of the upper frame 13. 【0116】Referring to Figures 19(a) and 19(b), the valve cylinder 94 includes an air inlet 94a, an air outlet 94b, a packing mounting section 94c, and a mounting section 94d. In the figure, the left end is open, and the packing mounting section 94c is provided in the opening. A first packing 94c1 is attached to the packing mounting section 94c (see Figure 21(b)). The air inlet 94a is located to the right of the packing mounting section 94c in the figure. An air supply source (not shown) is connected to the air inlet 94a, and compressed air is introduced. The air outlet 94b is located to the right of the air inlet 94a in the figure. One end of the air pipe 44c is connected to the air outlet 94b. The other end of the air pipe 44c is connected to the air chamber 89c (see Figures 16(a) and 16(b)). As a result, air discharged from the air discharge section 94b is introduced into the air chamber 89c. This causes the pressing pin member 91 to move in the protruding direction and press against the transmission piece 90. The mounting section 94d is provided with a pin hole 94d1. The pin-shaped portion 84b of the cylinder support member 84 is inserted through the pin hole 94d1. As a result, the valve cylinder 94 is attached to the connecting shaft 23a. 【0117】 The valve piston 95 is equipped with a second packing 95a at its tip. The valve piston 95 is provided in a slidable state within the valve cylinder 94 such that the position of the second packing 95a can move between the region between the air inlet 94a and the air outlet 94b within the valve cylinder 94 and the region further forward (to the right in the figure) than the air outlet 94b. This makes it possible to create a state in which the discharge of air from the air outlet 94b is stopped and a state in which the discharge of air is permitted. In other words, when the position of the second packing 95a is in the region between the air inlet 94a and the air outlet 94b, air is introduced into the region between the air inlet 94a and the second packing 95a, but the air outlet 94b is blocked by the second packing 95a. As a result, the discharge of air from the air outlet 94b is stopped. On the other hand, if the position of the second packing 95a is on the tip side of the air discharge section 94b, the air discharge section 94b will be in an open state. Therefore, air discharge from the air discharge section 94b is permitted. 【0118】 Furthermore, the valve piston 95 is biased to move to the right by air pressure because the second packing 95a is located to the right of the air inlet 94a in the figure. 【0119】 Referring to Figures 20(a) to 20(c), the slide case member 96 includes a bent portion 96a, a mounting portion 96b, a guide portion 96c, and a wire member holding portion 96d. 【0120】 The bent portion 96a is provided between the guide portion 96c and the wire member holding portion 96d. The wire member 68d is wrapped around the bent portion 96a. The wire member 68d is connected to the dial member 31 included in the height position change operation portion 32 via the wire member 68e. 【0121】 The mounting portion 96b is provided on the inner side of the bent portion 96a. The mounting portion 96b is equipped with a pin hole 96b1. The pin-shaped portion 85b of the bracket 85 is inserted through the pin hole 96b1. As a result, the slide case member 96 is attached to the pivot shaft 20. 【0122】 The guide portion 96c is a trough-shaped section, and the valve cylinder 94 is slidably arranged inside it. This allows the relative positions of the slide case member 96 and the valve cylinder 94 to be changed. A relay member 97 is also arranged inside the guide portion 96c so as to be movable relative to the longitudinal direction of the guide portion 96c. 【0123】 The wire member holding portion 96d holds the wire member 68d. This allows the wire member 68d to be stably wrapped around the bent portion 96a. 【0124】 The relay member 97 connects the wire member 68d and the valve piston 95. As a result, the wire member 68d and the valve piston 95 are connected via the relay member 97. As described above, the valve piston 95 is biased to the right in the figure by air pressure, but its movement to the right is restricted by its connection to the wire member 68d. 【0125】Here, we will explain the relationship between the change in the height position of the vehicle seat and the valve cylinder 94 and valve piston 95. The valve cylinder 94 is attached to the connecting shaft 23a. On the other hand, the slide case member 96, which has a bent portion 96a around which a wire member 68d connected to the valve piston 95 via a relay member 97 is wrapped, is attached to the pivot shaft 20. When the height position of the vehicle seat, that is, the height position of the upper frame 13, changes, the distance between the pin-shaped portion 84b and the pin-shaped portion 85b changes. As a result, the relative position between the valve cylinder 94 and the slide case member 96 changes. Specifically, the distance between the mounting portion 94d and the mounting portion 96b changes. On the other hand, the wire member 68d is connected to a dial member 31 included in the height position change operation unit 32. Therefore, when the position of the upper frame 13 changes by operating the dial member 31, the state of the wire member 68d also changes simultaneously. As a result, the relationship between the valve cylinder 94 and the valve piston 95 is maintained. 【0126】 Here, the operation of each of these parts will be explained with reference to Figures 22(a) to 22(d). Figure 22(a) shows the state in which the vehicle seat height is adjusted to the lowest position, and Figure 22(b) shows the state in which the vehicle seat height is adjusted to one level higher. Figure 22(c) shows the state in which the vehicle seat height is adjusted to the highest position, and Figure 22(d) shows the state in which the vehicle seat height is lowered while the vehicle seat height is adjusted to the highest position. 【0127】 Referring to Figure 22(a), the distance from the wire member holding portion 96d to the relay member 97 is defined as distance L1. The distance between the mounting portion 94d and the mounting portion 96b is defined as distance L2. Distance L1 is the distance corresponding to the height of the vehicle seat set by operating the dial member 31. In other words, it remains constant unless the height of the vehicle seat is changed by operating the dial member 31. However, the higher the vehicle seat height is set by operating the dial member 31, the longer distance L1 becomes. On the other hand, distance L2 changes according to the height of the vehicle seat. Specifically, as the height of the vehicle seat increases, distance L2 becomes longer. 【0128】The difference in distance L1 between the height position setting stages and the difference in distance L2 between the height position setting stages are set to be approximately the same. Therefore, the relative positions of the valve cylinder 94 and the valve piston 95 are approximately the same. This makes it possible to maintain a state in which no air is discharged from the air discharge section 94b. 【0129】 Here, we compare the state shown in Figure 22(c) with the state shown in Figure 22(d). In both of these states, the height of the vehicle seat is adjusted to the highest position by operating the dial member 31. In the state shown in Figure 22(d), the height of the vehicle seat is lowered from that state, and the distance L2 is shortened. As a result, the second packing 95a moves to the right relative to the air discharge section 94b. As a result, air is discharged from the air discharge section 94b. The discharged air is introduced into the air chamber 89c. Then, the pressing pin member 91 moves in the direction of protrusion, rotating the transmission piece 90. This causes the piston section 81b to rotate, increasing the damping force of the shock absorber 81. 【0130】 When the vehicle seat height returns to its original position, the introduction of air from the air intake section 94a stops. Consequently, the introduction of air into the air chamber 89c also stops. Since the transmission piece 90 is biased in the return direction by the spring 66g, the transmission piece 90 returns to its original state. As a result, the damping force of the shock absorber 81 returns to its originally set state. 【0131】 In this embodiment, the height position change detection unit 93 detects the lowering of the vehicle seat, and accordingly, the piston portion rotation unit 88 rotates the piston portion 81b of the shock absorber 81. As a result, the damping force of the shock absorber 81 is automatically adjusted. Furthermore, the transmission piece 90 returns to its original position due to the spring 66g, and the damping force of the shock absorber 81 also returns to its original state. 【0132】Here, other embodiments will be described with reference to Figures 23(a) and 23(b). In the above embodiment, the height position change detection unit 93 was configured by a mechanical mechanism. However, the height position change detection unit 93 only needs to be able to detect changes in the height position of the vehicle seat. For this reason, for example, a sensor unit may be used to detect the displacement of a part that is displaced in accordance with the change in the height position of the vehicle seat. When a displacement is detected, the piston portion 81b may be driven by an actuator such as a motor. In other words, a sensor unit can be used as another embodiment of the height position change detection unit, and an actuator can be used as another embodiment of the piston portion rotation unit. 【0133】 In the example shown in Figures 23(a) and 23(b), a sensor unit 6 is provided to detect a change in the position of a roller member 25 moving within the side frame 13a in accordance with a change in the height position of the upper frame 13. The sensor unit 6 is connected to a control unit 7. The control unit 7 is connected to an actuator 8. The actuator 8 drives a piston portion 81b. The roller member 25 is displaced as indicated by arrow 5 in the figure. When such a roller member 25 moves to the position of the sensor unit 6 as shown in Figure 23(b), the displacement of the roller member 25 is detected. The signal detected by the sensor unit 6 is notified to the control unit 7, and the control unit 7 drives the actuator 8. As a result, the damping force of the shock absorber 81 changes. The actuator 8 can easily return the piston portion 81b to its original position. The sensor unit 6 may be, for example, an electrical switch or a laser light transmission and reception device. It may also be an acceleration sensor installed at the location of displacement. In other words, any device that can detect changes in the height position of the vehicle seat can be used. 【0134】Furthermore, the actuator 8 may be configured to rotate a dial member 82 (see, for example, Figure 1(a)) included in the damping force adjustment mechanism 80. The dial member 82 can be operated manually by the passenger to adjust the damping force of the shock absorber 81. By driving such a dial member 82 with the actuator 8, the piston portion 81b can be driven via the wire members 68g and 68f (see Figure 14). 【0135】 According to this embodiment, the stiffness of the shock absorber 81 is automatically adjusted in accordance with the operation of the suspension system. 【0136】 [Second Embodiment] Next, a second embodiment will be described with reference to Figures 24 to 28. The second embodiment includes a flow control valve mechanism 100 incorporated into the damping force adjustment mechanism 80 of the air suspension device 11 of the first embodiment. The flow control valve mechanism 100 functions as a delay mechanism that delays the operation of the piston portion rotating part 88, more specifically, the operation of the pressing pin member 91. 【0137】 Referring to Figure 24, the flow control valve mechanism 100 is installed interposed in the air pipe 44c that connects the valve cylinder 94 of the height position change detection unit 93 and the air chamber 89c of the piston portion rotating part 88. For convenience, in the following description, the air pipe 44c will be referred to as the first portion 44c1 between the valve cylinder 94 and the flow control valve mechanism 100, and the air pipe 44c2 between the flow control valve mechanism 100 and the piston portion rotating part 88. 【0138】 Referring to Figures 25(a) and 25(b), the flow control valve mechanism 100 comprises a main body 101, a first connection port 102, and a second connection port 103. A third packing 102a is attached to the first connection port 102, and the first portion 44c1 of the air pipe 44c is connected to it. The second portion 44c2 of the air pipe 44c is connected to the second connection port 103. 【0139】Referring to Figures 26(a) to 26(c), the main body 101 has a space 101b inside. The second connection port 103 is formed from a separate part from the main body 101. The part forming the second connection port 103 is installed with the end to which the fourth packing 103a is attached inserted into the main body 101. The main body 101 has a first inner circumferential wall 101a. The first inner circumferential wall 101a is formed on the valve cylinder 94 side. That is, the first inner circumferential wall 101a is formed on the upstream side when air flows from the valve cylinder 94 toward the air chamber 89c of the piston rotating part 88 during intake. The part forming the second connection port 103 is inserted into the main body 101 to form the second inner circumferential wall 103b. The second inner circumferential wall 103b is formed on the piston rotating part 88 side. That is, it is formed on the downstream side during the intake described above. Furthermore, the main body portion 101 has multiple inwardly projecting protrusions 101c1 formed on the inner circumferential wall surface of the cylindrical portion (see Figure 27(a), etc.). 【0140】 A first movable valve 104 and a second movable valve 105 are provided within the main body 101. The first movable valve 104 is positioned on the side of the first inner circumferential wall 101a. The second movable valve 105 is positioned on the side of the second inner circumferential wall 103b. A spring 106 is sandwiched between the first movable valve 104 and the second movable valve 105. The spring 106 may be an elastic body other than a coil spring. The first movable valve 104 and the second movable valve 105 can each move within the main body 101 in the direction of air flow. 【0141】 Referring to Figures 27(a) to 27(c), the first movable valve 104 is a generally disc-shaped member, with an annular fifth packing 104a on one side and a spring support portion 104b on the other side. The outer circumferential surface of the first movable valve 104 slides against a plurality of convex portions 101c1 provided on the main body portion 101. As a result, an air passage portion 101c is formed between the first movable valve 104 and the main body portion 101. The first movable valve 104 has a first orifice hole 104d in its center. 【0142】Referring to Figures 27(d) to 27(f), the second movable valve 105 is a generally disc-shaped member, with an annular sixth packing 105a on one side and a spring support portion 105b on the other side. The outer circumferential surface of the second movable valve 104 slides against a plurality of convex portions 101c1 provided on the main body portion 101. As a result, an air passage portion 101c is also formed between the second movable valve 104 and the main body portion 101. The second movable valve 105 has a second orifice hole 105d in its center. 【0143】 The first movable valve 104 is positioned within the main body 101 such that the fifth packing 104a faces the first inner circumferential wall 101a. The second movable valve 105 is positioned within the main body 101 such that the sixth packing 105a faces the second inner circumferential wall 103b. In other words, the first movable valve 104 and the second movable valve 105 are positioned within the main body 101 such that the spring support portion 104b and the spring support portion 105b face each other. The spring 106 is supported by the spring support portion 104b and the spring support portion 105b. The spring 106 biases the first movable valve 104 toward the first inner circumferential wall 101a and the second movable valve 105 toward the second inner circumferential wall 103b. 【0144】 The diameter of the first orifice hole 104d of the first movable valve 104 and the diameter of the second orifice hole 105d of the second movable valve 105 can be set as appropriate. In this embodiment, the diameter of the second orifice hole 105d is set to be larger than that of the first orifice hole 104d. Not only the relative size of the orifice holes, but also their individual sizes can be set as appropriate. The first orifice hole 104d defines the amount of air exhausted per unit time when air is exhausted from the air chamber 89c. On the other hand, the second orifice hole 105d defines the amount of air intake per unit time when air is drawn into the air chamber 89c. The smaller the value of the diameter of either orifice hole, the more the amount of air flow is restricted, which has a greater effect in delaying the operation of the piston portion rotating part 88, that is, the pressing pin member 91. In other words, the diameter of the orifice hole is an adjustment element for operating the pressing pin member 91 at a desired speed. 【0145】Now, referring to Figure 26(b), we will explain the case during intake, that is, when air is supplied from the valve cylinder 94 toward the piston rotating portion 88. When the height position change detection unit 93 is activated and air flows from the valve cylinder 94 into the flow control valve mechanism 100, the first movable valve 104 moves toward the side away from the first inner circumferential wall 101a while compressing the spring 106. As a result, the air can not only pass through the first orifice hole 104d as indicated by arrow 6a, but also through the air passage section 101c formed on the outer edge of the outer peripheral portion as indicated by arrow 6b. The air that has passed through the first movable valve 104 presses the second movable valve 105 against the second inner circumferential wall 103b. As a result, the sixth packing 105a is pressed against the second inner circumferential wall 103b. As a result, the passage of air through the air circulation section 101c is blocked, and air can only pass through the second orifice hole 105d, as indicated by arrow 7a. Consequently, as described above, the amount of air drawn into the air chamber 89c per unit time is restricted by the diameter of the second orifice hole 105d. In other words, the amount of air drawn in is determined by the diameter of the second orifice hole 105d, resulting in a gradual intake. Consequently, the piston section rotation part 88 begins to operate with a delay after the height position change detection unit 93 has been activated. 【0146】Next, referring to Figure 26(c), we will explain the case during exhaust, that is, when air is exhausted from the air chamber 89c of the piston rotating part 88. When the upper frame 13 returns to the set position from the lowered state, the supply of air from the valve cylinder 94 of the height position change detection unit 93 to the air chamber 89c stops. Then, the transmission piece 90 of the piston rotating part 88 returns to its original state due to the elastic force of the spring 66g. At this time, the air in the air chamber 89c is exhausted through the air pipe 44c. When the exhausted air flows into the flow control valve mechanism 100, the second movable valve 105 moves away from the second inner circumferential wall 103b while compressing the spring 106. As a result, the air can not only pass through the second orifice hole 105d as indicated by arrow 7b, but also through the air flow section 101c formed on the outside of the outer peripheral edge as indicated by arrow 7c. The air that has passed through the second movable valve 105 presses the first movable valve 104 against the first inner circumferential wall 101a. As a result, the fifth packing 104a is pressed against the first inner circumferential wall 101a. Consequently, the passage of air through the air flow section 101c is blocked, and the air can only pass through the first orifice hole 104d, as indicated by arrow 6c. As a result, as described above, the amount of air exhausted per unit time when air is exhausted from the air chamber 89c is restricted by the diameter of the first orifice hole 104d. In other words, the amount of air exhausted is corresponding to the diameter of the first orifice hole 104d, resulting in a gradual exhaust. Consequently, the piston portion rotating part 88 returns to its original position after a delay following the stopping of operation of the height position change detection unit 93. In short, even if the position of the upper frame 13 exceeds the set position, the piston part rotation section 88 does not immediately return to its original position and lags behind the movement of the upper frame 13, thus mitigating the movement after the upper frame 13 has bounced upward. 【0147】 Now, referring to Figure 28, the delay effect of the piston portion rotation part 88, that is, the shock absorber 81, will be explained. In the following explanation, the time it takes for the stiffness of the shock absorber 81 to change will be compared when the flow control valve mechanism 100 is not installed and when the flow control valve mechanism 100 is installed. 【0148】First, let's explain the case where the flow control valve mechanism 100 is not installed. In Figure 28, the change in stiffness of the shock absorber 81 when the flow control valve mechanism 100 is not installed is shown by a dashed line. The "boundary" shown in Figure 28 indicates the position where the stiffness of the shock absorber 81 switches between a stiff state and a soft state. Referring to Figure 28, at time ta, when the height of the suspension, that is, the height of the upper frame 13, drops to the boundary position, air is supplied to the air chamber 89c, the pressure pin 91 moves, the transmission piece 90 is pushed, and the shock absorber 81 becomes stiff. The time it takes for the shock absorber 81 to reach its stiffest state is Δt1. 【0149】 Then, at time tb, when the suspension height, that is, the height of the upper frame 13, returns to the boundary position, air escapes from the air chamber 89c, the transmission piece 90 returns to its original position, and the stiffness of the shock absorber 81 returns to its original state. In other words, the stiffness of the shock absorber 81 becomes softer. The time it takes for the shock absorber 81 to reach its softest state is Δt3. 【0150】 Next, we will explain the case where the flow control valve mechanism 100 is installed. In Figure 28, the change in stiffness of the shock absorber 81 when the flow control valve mechanism 100 is installed is shown by a thick solid line. Referring to Figure 28, at time ta, when the height of the suspension, that is, the height of the upper frame 13, drops to the boundary position, air is supplied to the air chamber 89c, the pressure pin 91 moves, the transmission piece 90 is pushed, and the shock absorber 81 becomes stiffer. At this time, the air passes through the flow control valve mechanism 100. The air flow rate decreases due to the action of the second movable valve 105. Therefore, the time until the shock absorber 81 reaches its stiffest state is Δt2, which is longer than Δt1. In other words, the installation of the flow control valve mechanism 100 causes a delay of Δt2 - Δt1. 【0151】Then, at time tb, when the suspension height, that is, the height of the upper frame 13, returns to the boundary position, air escapes from the air chamber 89c, the transmission piece 90 returns to its original position, and the stiffness of the shock absorber 81 returns to its original state. At this time, the air passes through the flow control valve mechanism 100. The air flow rate decreases due to the action of the first movable valve 104. Therefore, the time it takes for the shock absorber 81 to reach its softest state is Δt4, which is longer than Δt3. In other words, the presence of the flow control valve mechanism 100 causes a delay of Δt4 - Δt3. 【0152】 In this way, by equipping the flow control valve mechanism 100, a delay effect can be obtained in both cases: when the stiffness of the shock absorber 81 shifts to the stiffer side and when it shifts to the softer side. 【0153】 The initial stiffness of the shock absorber 81, that is, the position indicated as "soft" in Figure 28, can be adjusted by the damping force adjustment mechanism 80. In addition, the stiffness of the shock absorber 81 through automatic adjustment, that is, the position indicated as "hard" in Figure 28, can be changed by the length of the pressure pin 91. 【0154】 In this way, the flow control valve mechanism 100 can slow down the change in stiffness of the shock absorber 81. The smaller the diameter of the first orifice hole 104d and the second orifice hole 105d, the longer the delay time can be made, and the slower the change in stiffness can be made. The delay time can also be adjusted by the position of the flow control valve mechanism 100 in the air pipe 44c. Specifically, the delay time can be made longer by installing the flow control valve mechanism 100 closer to the valve cylinder 94, that is, by shortening the first part 44c1 of the air pipe 44c and lengthening the second part 44c2. This is because the volume of the second part 44c2 becomes larger. 【0155】 In this way, by providing the flow control valve mechanism 100, it is possible to suppress the shock absorber 81 from becoming suddenly stiff, and thus prevent the passenger from feeling the seat bottoming out. 【0156】[Third Embodiment] Next, a third embodiment will be described with reference to Figures 29(a) to 29(d). 【0157】 Figures 29(a) and 29(b) show a flow control valve mechanism 110 obtained by removing the first movable valve 104 from the flow control valve mechanism 100 of the second embodiment. Such a flow control valve mechanism 110 can delay the operation of the piston portion rotating part 88 during intake. The configuration and operation of each part are the same as the second embodiment except that the first movable valve 104 is not installed, so the same reference numerals are used in the drawings for the same components, and detailed explanations are omitted. 【0158】 Figures 29(c) and 29(d) show a flow control valve mechanism 120 obtained by removing the second movable valve 104 from the flow control valve mechanism 100 of the second embodiment. Such a flow control valve mechanism 120 can delay the operation of the piston portion rotating part 88 during exhaust. The configuration and operation of each part are the same as the second embodiment except that the second movable valve 104 is not installed, so the same reference numerals are used in the drawings for the same components, and detailed explanations are omitted. 【0159】 [Fourth Embodiment] Next, a fourth embodiment will be described with reference to Figure 30. The flow control valve mechanism 130 of the fourth embodiment comprises a main body 131, a first connecting portion 132 provided with a seventh packing 132a, and a second connecting portion 133 provided with an eighth packing 133a. These correspond to the main body 101, the first connecting portion 102 provided with a third packing 102a, and the second connecting portion 103 provided with a fourth packing 103a of the flow control valve mechanism 100 of the second embodiment. For this reason, a detailed explanation will be omitted here. 【0160】The flow control valve mechanism 130 includes a valve body 134 in place of the first movable valve 104 and the second movable valve 105 of the second embodiment. The valve body 134 has a ninth packing 134a on one side and a tenth packing 134b on the other side. The valve body 134 also has an orifice hole 134c. Unlike the first movable valve 104 and the second movable valve 105 of the second embodiment, the valve body 134 does not move within the main body 131 and does not have an air passage on its outer peripheral edge. In other words, air passes only through the orifice hole 134c during both intake and exhaust. Thus, the flow control valve mechanism 130 of the fourth embodiment is simpler and has fewer adjustment elements compared to the flow control valve mechanism 100 of the second embodiment, but it can obtain the effect of delaying the operation of the piston portion rotation part 88. 【0161】 [Fifth Embodiment] Next, a fifth embodiment will be described with reference to Figures 31(a) and 31(b). 【0162】 The fifth embodiment includes a spring 150 as a spring member, which serves as a delay mechanism to delay the operation of the piston portion rotating part 88. The spring 150 is a coil spring, but it may be an elastic member other than a coil spring. 【0163】 The spring 150 is located within the air chamber 89c. The spring 150 is positioned on the tip side of the flange portion 91a of the pressing pin member 91, that is, in the region closer to the transmission piece 90. The length of the spring 150 is set to allow it to move freely within the air chamber 89c when the pressing pin member 91 is most fully retracted within the air chamber 89c. In other words, the free length of the spring 150 is shorter than the stroke amount of the pressing pin member 91a. Such a spring 150 delays the operation of the piston portion rotation part 88 during intake, similar to the second movable valve 105 in the second embodiment. 【0164】When air is supplied into the air chamber 89c, the pressing pin member 91 moves to press against the transmission piece 90. At the beginning of the movement, the spring 150 is not in contact with the flange portion 91a. Therefore, the pressing pin member 91 moves at a speed corresponding to the amount of intake air. After the flange portion 91a comes into contact with the spring 150, it moves while compressing the spring 150. As a result, the movement speed of the pressing pin member 91 slows down, and the rotation speed of the transmission piece 90 slows down. Consequently, the change in the stiffness of the shock absorber 81 becomes gradual. 【0165】 In this way, by providing the spring 150, the movement of the piston portion rotating part 88 during heating can be delayed. 【0166】 [Sixth Embodiment] Next, the sixth embodiment will be described with reference to Figure 32. The sixth embodiment is a configuration in which, compared to the fifth embodiment which is equipped with a spring 150, a buffer member 89g is further provided on the pressing projection 91a1 and the air introduction wall 89f. These elements delay the operation of the piston portion rotation part 88 during intake, similar to the first movable valve 104 in the second embodiment. 【0167】 The air inlet wall 89f is the part to which the air pipe 44c is connected. The air inlet wall 89f is provided with an air inlet hole 89f1 that communicates with the air chamber 89c. The air inlet wall 89 is provided with a buffer member 89g facing into the air chamber 89c. The buffer member 89g is a rubber material, but it may be any material that can slow down the movement of a moving member, such as a viscoelastic material. 【0168】 The pressing projection 91a1 is provided on the flange portion 91a and faces the cushioning member 89g. The pressing projection 91a1 comes into contact with the cushioning member 89g during exhaust. In other words, the pressing projection 91a1 presses against the cushioning member 89g, which slows down the return of the pressing pin member 91 and slows down the rotational speed of the transmission piece 90. As a result, the change in the stiffness of the shock absorber 81 becomes more gradual. 【0169】The embodiments described above are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention, and it is obvious from the above description that various other embodiments are possible within the scope of the present invention. 【0170】 11 Air suspension device for vehicle seat 12 Lower frame 13 Upper frame 15a, 15b X-link 16a, 16c Outer link member 18 Air spring 20 Rotating shaft 21a, 21b Connecting shaft 23a, 23b Connecting shaft 80 Damping force adjustment mechanism 81 Shock absorber 88 Piston part rotating section 89 Main body 89c Air chamber 90 Transmission piece 91 Pressing pin member 93 Height position change detection section 94 Valve cylinder 95 Valve piston 96 Slide case member 97 Intermediate member 89g Cushioning member 91a1 Pressing projection 100, 110, 120, 130 Flow control valve mechanism 101 Main body 101a First inner circumferential wall 101c Air flow section 101c1 Protruding part 103b Second inner wall 104 First movable valve 104d First orifice hole 105 Second movable valve 105d Second orifice hole 106 Spring 131a First inner wall 133b Second inner wall 134 Valve body 134c Orifice hole 150 Spring

Claims

1. A lower frame installed on the floor side of the vehicle; an upper frame positioned above the lower frame and provided below the vehicle seat of the vehicle; a pair of X-shaped intersecting members positioned on the left and right sides between the lower frame and the upper frame, connected to the lower frame and the upper frame to support the upper frame so as to be vertically movable, with the X-shaped intersecting portions pivotally mounted on a shaft body connecting them; an elastic support mechanism provided between the lower frame and the upper frame to elastically support the upper frame relative to the lower frame; a vertical movement mechanism for moving the upper frame up and down; a shock absorber comprising a cylinder portion and a piston portion slidably provided with respect to the cylinder portion and capable of adjusting damping force by rotation in the circumferential direction, with one of the cylinder portion and the piston portion attached to the upper frame side and the other attached to the lower frame side; a height position change detection unit for detecting changes in the height position of the upper frame; A suspension device for a vehicle seat, comprising: a piston portion rotating part that rotates the piston portion of the shock absorber in response to the detection of a change in the height position of the upper frame by the height position change detection part; 2. The height position change detection unit comprises a valve cylinder attached to the lower frame side, a valve piston slidably provided within the valve cylinder and equipped with a second packing that is movable between a region within the valve cylinder between the air introduction portion and the air discharge portion and a region beyond the air discharge portion, the piston portion rotating part comprises an air chamber into which air discharged from the air discharge portion is introduced, a pressure pin member provided so as to be retractable relative to the air chamber and moves in a protruding direction when air is introduced into the air chamber, and a transmission piece that engages with the piston portion of the shock absorber and rotates the piston portion so as to increase the damping force of the shock absorber when pressed by the pressure pin member, and is biased by an elastic member in a direction that decreases the damping force of the shock absorber.

3. The elastic support mechanism and the vertical movement mechanism are air springs that move the upper frame up and down by pressure changes caused by the supply of compressed air from a supply source and exhaust to the outside, and include an air supply valve that opens and closes an air supply pipe to the air spring and an exhaust valve that opens and closes an exhaust pipe from the air spring, an air supply / exhaust valve body provided on one link member that forms one of the left or right side X links, an air supply control cam provided on the one link member that controls the opening and closing of the air supply valve, an exhaust control cam that controls the opening and closing of the exhaust valve, a cam member pivotally mounted on the shaft and stretched on the other link member that intersects with the one link member and rotates together with the other link member, and an arm member pivotally mounted on the shaft so as to be rotatable together with the cam member, which rotates the air supply control cam or the exhaust control cam in accordance with the direction of rotation of the X link to open and close the air supply valve or the exhaust valve, A suspension device for a vehicle seat according to claim 2, comprising: a reference height position changing mechanism which rotates the air intake control cam or the exhaust control cam by pulling or releasing a first wire member connected to the cam member, thereby rotating the arm member through the cam member, to open and close the air intake valve or the exhaust valve, thereby moving the upper frame upward or downward due to a pressure change in the air spring, and setting a new predetermined position as the reference height; the height position change detection unit comprises a slide case member attached to the shaft body connecting the X-shaped intersection portions of the X-link and slidably provided with respect to the valve cylinder; the valve piston is connected to a second wire member which is linked to the movement of the first wire member, the second wire member is wrapped around a bent portion of the slide case member, and changes the relative position of the valve piston with respect to the slide case member in accordance with changes in the positional relationship between the slide case member and the valve cylinder, thereby maintaining the position of the valve piston with respect to the valve cylinder.

4. The height position change detection unit is a sensor unit that detects the displacement of a part that is displaced in accordance with a change in the height position of the upper frame, and the piston portion rotation unit is an actuator that operates in accordance with the detection signal of the sensor unit to rotate the piston portion, as described in claim 1.

5. The suspension device for a vehicle seat according to claim 2, further comprising a delay mechanism for delaying the operation of the pressing pin member.

6. The suspension device for a vehicle seat according to claim 5, wherein the delay mechanism is a flow control valve mechanism interposed in an air pipe connecting the air discharge section of the position change detection section and the air chamber of the piston portion rotation section, and the flow control valve mechanism is provided with at least an orifice hole for restricting the amount of air flowing between the air discharge section and the air chamber.

7. The suspension device for a vehicle seat according to claim 6, wherein the flow control valve mechanism comprises: a main body having a space formed inside that communicates with the air pipe; at least one movable valve arranged to be movable within the space along the direction of air flow within the space; and an elastic member that biases the movable valve to one side within the space formed in the main body, the movable valve comprising: an orifice hole penetrating in the direction of air flow; an air flow portion formed on its periphery; and a packing that is pressed against the inner circumferential wall of the main body by the elastic member, thereby blocking the flow of air between the space and the air pipe via the air flow portion.

8. The suspension device for a vehicle seat according to claim 7, wherein the flow rate control valve comprises two of the moving valves between opposing inner circumferential walls of the space, and the elastic body is positioned between the two moving valves and biases the packing of one of the moving valves to press against one of the inner circumferential walls, and the packing of the other moving valve to press against the other inner circumferential wall.

9. The suspension device for a vehicle seat according to claim 8, wherein the diameter of the orifice hole formed in one of the movable valves is different from the diameter of the orifice hole formed in the other movable valve.

10. The suspension device for a vehicle seat according to claim 5, wherein the delay mechanism is an elastic member positioned in the air chamber on the side of the pressing pin member that is closer to the protruding direction than the flange portion of the pressing pin member.

11. The suspension device for a vehicle seat according to claim 10, wherein the elastic member is a spring member whose free length is shorter than the stroke amount of the pressing pin member.

12. The suspension device for a vehicle seat according to claim 5, wherein the delay mechanism is provided on the main body of the piston portion rotating part, and when air is exhausted from the air chamber, the pressing pin member moving within the air chamber comes into contact with it, thereby reducing the speed of movement of the pressing pin member.

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