JP2005053314A - Suspension device of seat for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly prevent bottoming in a suspension device of a seat for a vehicle. <P>SOLUTION: The suspension device M comprises upper and lower frames 10 and 20 mutually approachable/separable, a link 30 that is rotatably connected to one frame 10 and can slide relative to the other frame 20, and a suspension spring 40 for energizing the link 30 in the direction separating the upper and lower frames 10 and 20 from each other. The other frame 20 is provided with a cam means 25. The cam means 25 increases telescopic degree of the suspension spring 40 when the upper and lower frames 10 and 20 lie at the approach positions than that when they lie at the separation positions in cooperation with the link 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a seat suspension device used in a vehicle such as an industrial machine.

  For example, the seat described in Patent Document 1 is provided with a suspension device. The suspension device is provided with a link that tilts upward toward the rear. A rear end portion of the link is rotatably connected to the upper frame, and a front end portion is connected to the lower frame so as to be slightly slidable. Further, the rear end portion of the suspension spring is hooked in the vicinity of the rotation shaft at the rear end of the link. The front end portion of the suspension spring is hooked on the upper frame. When vibration is input to the seat, the lower frame moves up and down relative to the upper frame, and the link rotates about the rotation axis. Along with this, the suspension spring expands and contracts. As a result, vibration is absorbed.

  In the suspension device described in Patent Document 2, the link is rotatably connected to the lower frame, and a roller is provided at the upper end of the link, and the roller is slidably pressed against the upper frame. The front end portion of the suspension spring is hooked on the lower frame, and the rear end portion is hooked on the link.

Japanese Patent Laid-Open No. 2001-233091 (first page, FIG. 1) JP2002-211300 (first page, FIG. 1)

  Even in the seat with the suspension device as described above, when shock vibration is input, the vertical movement stroke may reach the limit due to the link or its bracket hitting the frame or the like, which may cause bottoming. Then, the impact is transmitted directly to the passenger. Although some have provided an impact absorbing member such as rubber at a location where the abutment occurs between the link and another member, it is not sufficient to eliminate the bottom sensation.

In order to solve the above problems, the present invention includes (a) upper and lower frames that can approach and separate from each other, and (b) a link that is rotatably connected to one frame and slidable with respect to the other frame. (C) In the suspension device for a vehicle seat provided with a suspension spring that biases the link in a direction in which the upper and lower frames are separated from each other, the upper and lower frames are coupled to the other frame in cooperation with the link. A cam means is provided for increasing the degree of expansion and contraction of the suspension spring when in the approach position than when in the separation position.
Here, it is desirable that the cam means gradually increase the degree of expansion and contraction of the suspension spring as the upper and lower frames approach each other.

  According to the above-described characteristic configuration, when the upper and lower frames approach each other as the shock is input, the degree of shock absorption by the suspension spring when the approaching stroke is closer to the approaching position than at the beginning of the approaching stroke. Can be increased. As a result, bottom-out can be reliably prevented. Even if it bottoms out, the degree can be made sufficiently small.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 and 2 show a suspension device M for a vehicle seat such as an industrial machine. The suspension device M includes upper and lower frames 10 and 20, a pair of left and right links 30 provided between the frames 10 and 20, and a pair of left and right suspension springs 40 including a tension coil spring.

  The lower frame 20 is installed on the floor of the vehicle cabin. A seat cushion with a backrest is provided on the upper side of the upper frame 10. The upper and lower frames 10 and 20 are connected to each other via a pair of left and right X-shaped link mechanisms 50 so as to be close to and away from each other. In the figure, reference numerals 51 and 52 are links constituting the X-type link mechanism 50, and reference numeral 53 is a rotating shaft that rotatably connects these links 51 and 52 to the frames 10 and 20, respectively. Is a slide guide for slidably connecting the links 51 and 52 to the frames 10 and 20.

  Each link 30 of the suspension device M has a short arm portion 31 that protrudes obliquely upward toward the front and a long arm portion 32 that extends long obliquely downward, and has a generally “H” shape. A pair of left and right brackets 13 are suspended from the lower surface of the upper frame 10, and a rotary shaft 14 is horizontally stretched between the brackets 13. The corners of the pair of links 30 (intersections of the short arm portion 31 and the long arm portion 32) are connected to the rotation shaft 14 so as to be rotatable. A connecting shaft 33 is stretched horizontally between the distal ends of the short arm portions 31 of the pair of links 30. On the other hand, a connecting shaft 34 is stretched horizontally between the lower end portions of the long arm portion 32. Rollers 35 are rotatably attached to the left and right ends of the connecting shaft 34, respectively.

  The pair of suspension springs 40 of the suspension device M extend in the front-rear direction along the lower surface of the upper frame 10. The rear end portions of the suspension springs 40 are hooked on both end portions of the connecting shaft 33, respectively. On the other hand, the front end portions of the suspension springs 40 are respectively hooked on the left and right hooks 42 b of the locking member 42. A female screw hole 42a is formed at the center of the locking member 42, and an adjusting screw 41 extending in the front-rear direction is screwed into the female screw hole 42a. A front end portion of the adjustment screw 41 is rotatably supported by the upper frame 10.

The suspension spring 40 pulls the short arm portion 31 of the link 30 forward via the connecting shaft 33. As a result, the long arm portion 32 of the link 30 is urged to rotate in a standing direction. As a result, the upper frame 10 and thus the upper seat cushion are elastically supported.
Further, when the adjusting screw 41 is turned, the position of the locking member 42 can be adjusted in the front-rear direction, so that the spring force of the suspension spring 40 can be adjusted.
In addition, although illustration is abbreviate | omitted, between the upper and lower frames 10 and 20, the shock absorber (damper) for further damping a vibration is provided.

The characteristic part of the present invention will be described.
A guide plate 25 (cam means) is fixed to the upper surface of the lower frame 20 of the suspension device M by welding or bolting. The guide plate 25 integrally includes a flat portion 25a that is horizontal along the lower frame 20, and a slope portion (inclined cam surface) 25b that continues to the front side of the flat portion 25a. The slope portion 25b is smoothly connected to the flat portion 25a and is inclined upward so that the gradient gradually increases toward the front.
The roller 35 of the link 30 is pressed against the guide plate 25.

  As shown in FIG. 1, the roller 35 is positioned on the flat portion 25 a of the guide plate 25 in a state where no vibration is input to the suspension device M. At this time, the upper and lower frames 10 and 20 are sufficiently separated.

  As shown in FIG. 3, when an upward impact is input to the lower frame 20, the lower frame 20 rises toward the upper frame 10. As the lower frame 20 moves up, the roller 35 rolls forward along the upper surface of the guide plate 25 and rotates in the direction in which the link 30 falls. As a result, the suspension spring 40 extends and absorbs the impact.

  In the first half S0 of the lower stroke of the lower frame 20 (when the upper and lower frames 10, 20 are in the separated position), the roller 35 moves on the flat portion 25a of the guide plate 25. As shown in FIG. 4, at this time, the rising amount of the lower frame 20 and the extension amount of the suspension spring 40 are substantially proportional. That is, the degree of elongation of the suspension spring 40 with respect to the degree of elevation of the lower frame 20 (the slope of the thick line in FIG. 4) is substantially constant.

As shown by the solid line in FIG. 3, the roller 35 eventually moves from the flat portion 25a to the slope portion 25b, and the rising stroke of the lower frame 20 enters the second half S1. Here, since the flat part 25a and the slope part 25b are connected smoothly, a feeling of impact does not occur at the time of transition.
As shown in FIG. 4, in the second half S1 of the ascending stroke (when the upper and lower frames 10, 20 are in the approach position), the degree of extension of the suspension spring 40 with respect to the ascent degree of the lower frame 20 is greater than that in the first half S0. As a result, the effectiveness of the suspension spring 40 can be enhanced, and further shock absorption can be performed. As a result, it is possible to reliably prevent the lower frame 20 from being raised until the bottom is raised.

  Moreover, since the slope of the slope portion 25b is gradually increased, the degree of expansion and contraction of the suspension spring 40 is gradually increased as the lower frame 20 approaches the upper frame 10. As a result, bottom-out can be prevented more reliably. In addition, since the degree of expansion and contraction of the suspension spring 40 can be continuously and smoothly changed, there is no feeling of impact associated with the change.

The present invention is not limited to the above embodiment, and various modifications can be made.
For example, the link may be rotatably connected to the lower frame and slidable with respect to the upper frame, and one end portion of the suspension spring may be hooked on the lower frame, and the cam means may be provided on the upper frame.
The cam means may be formed integrally with the lower frame by press molding the lower frame.

1 is a side view showing a vehicle seat suspension device according to an embodiment of the present invention in a state in which an upper and a lower frame are spaced apart from each other at a maximum. It is a top view of the suspension apparatus of the said vehicle seat. It is a side view which shows the said suspension apparatus in the state which the lower frame entered into the second half of the up-and-down movement stroke. It is a graph of the expansion-contraction amount of the suspension spring with respect to the vertical motion stroke of a lower frame.

Explanation of symbols

M suspension device 10 upper frame 20 lower frame 25 guide plate (cam means)
25a Flat part 25b Slope part 30 Link 40 Suspension spring

Claims (2)

(A) upper and lower frames that can approach and separate from each other;
(B) a link rotatably connected to one frame and slidable relative to the other frame;
(C) a suspension spring that biases the link in a direction to separate the upper and lower frames;
In a vehicle seat suspension apparatus comprising:
Cam means is provided on the other frame, and the cam means cooperates with the link to increase the degree of expansion and contraction of the suspension spring when the upper and lower frames are in the approach position than when they are in the separation position. A suspension system for a vehicle seat. The suspension device for a vehicle seat according to claim 1, wherein the cam means gradually increases the degree of expansion and contraction of the suspension spring as the upper and lower frames approach each other.

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