JP2001260621A - Shock absorber support structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber support structure allowing setting of a large stroke amount of a shock absorber without changing a height level of the upper end of the shock absorber and setting of a large lever ratio of the shock absorber to a wheel stroke. SOLUTION: A lower arm 1 extends in the car width direction. A lower bush 10 is placed with being offset outwardly in the car width direction from the lower part of a cylindrical body 2a of the shock absorber 2. While the lower end of the cylindrical body 2a is loosely inserted into an opening 15 disposed in the lower arm 1, the lower bush 10 is connected to a bracket 16 projecting from the lower arm 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension system for a vehicle, and more particularly to a shock absorber support structure in which a lower portion of a shock absorber is supported by a suspension link such as a lower arm.

[0002]

2. Description of the Related Art As a support structure for a lower portion of a shock absorber, there is, for example, a structure described in Japanese Patent Application Laid-Open No. 2-28009. A shock absorber support structure in a multi-link independent suspension rear suspension device as shown in FIG. 7 will be described as an example. As shown in FIGS. 7 to 9, a lower arm extending in the vehicle width direction from the vehicle front-rear direction. 1, the lower end of the shock absorber 2 is supported. That is, the cylinder 2 of the shock absorber 2
a Lower bush 3 constituting a lower mounting portion is disposed below the lower end portion and on the axis P of the shock absorber 2. The lower bush 3 has an outer cylinder side fixed to the shock absorber 2 and an inner cylinder side connected to the lower arm 1 via a mounting pin. Thereby, the lower part of the shock absorber 2 is swingably supported by the lower arm 1. In FIG. 7, reference numeral 4 denotes a suspension member, and reference numeral 5 denotes a knuckle spindle.

As described above, conventionally, the mounting point K of the lower part of the shock absorber 2 to the suspension link is known.
Is located on the axis P of the shock absorber 2 and below the lower end of the cylinder 2a that is the main body of the shock absorber 2. Here, as described in JP-A-9-254623, the lower part of the shock absorber may be arranged offset from the axis of the suspension link. However, the lower bush, which constitutes the mounting portion at the lower part of the shock absorber, is also arranged below the lower end of the cylinder of the shock absorber and on the axis of the shock absorber. In addition, Japanese Patent Laid-Open No. 9-25
In the suspension device disclosed in Japanese Patent No. 4623, unlike the object of the present application, the lower part of the shock absorber is supported not by a suspension link but by an axle beam (wheel supporting member) integrated with a wheel. Things.

[0004]

Usually, assuming various road surfaces, the minimum ground clearance of the lower part of the shock absorber 2 and the lower arm 1 is determined so as to avoid interference with the road surface. However, in the conventional shock absorber support structure, as described above, since the lower bush 3 is disposed below the lower end of the cylindrical body 2a constituting the main body of the shock absorber 2, the lower bush 3 is disposed. The height level of the lower end portion of the cylindrical body 2a is set to be higher by the vertical dimension of 3, and the stroke amount of the shock absorber 2 is restricted accordingly. Here, the mounting height level of the upper part of the shock absorber 2 is restricted by the convenience of the living room space, and the upper part of the shock absorber 2 is desired to be set low.

Further, since the shock absorber 2 needs to be arranged so as not to interfere with the wheels, the wheel supporting members and other suspension parts, there is a limit to the arrangement outside in the vehicle width direction. However, shock absorber 2
Is located on the axis P of the conventional shock absorber 2, the lever ratio of the shock absorber 2 to the wheel stroke is determined by the position of the shock absorber 2 as shown in FIG. / L
2). Therefore, the lever ratio cannot be brought close to 1 by the limit of the arrangement of the shock absorber 2 outward in the vehicle width direction. It is preferable that the lever ratio is as close to 1 as possible.

For this reason, to improve the level of the damping force at the wheel end, the diameter of the shock absorber 2 must be increased accordingly, and the exclusive space of the shock absorber 2 increases and the mass increases. There are problems such as. The present invention has been made by paying attention to the above points, and it is possible to set the stroke amount of the shock absorber large without changing the height level of the upper end of the shock absorber or to increase the lever ratio of the shock absorber to the wheel stroke. The present invention provides a shock absorber support structure that can be set.

[0007]

According to a first aspect of the present invention, there is provided a shock absorber in which a lower portion of a shock absorber is supported by a suspension link and the shock absorber extends upward. A support structure, wherein a mounting point of the lower part of the shock absorber to a suspension link is offset in a vehicle width direction with respect to an axis of the shock absorber.

According to a second aspect of the present invention, with respect to the configuration of the first aspect, the point of attachment to the suspension link is offset outward in the vehicle width direction with respect to the axis of the shock absorber. It is characterized by the following.
Next, according to a third aspect of the present invention, in the configuration of the first or second aspect, the lower end of the cylinder of the shock absorber is provided in a recess or opening provided on the upper surface of the suspension link. It is characterized by being loosely inserted.

Next, according to a fourth aspect of the present invention, in addition to the configuration of the first aspect, the suspension link extends in the vehicle width direction as viewed from the vehicle front-rear direction. A lower bush is disposed so as to be offset from a lower side surface of the shock absorber in a link axis direction of the suspension link, and the lower bush is oriented in a direction orthogonal or substantially orthogonal to the link axis. By connecting the shock absorber lower part to the suspension link, the lower bush has high rigidity around the vertical axis and low rigidity around the axis parallel to the link axis,
In addition, the rigidity in the vertical axis direction is set high.

Here, the link axis is a line connecting between the vehicle body side and the wheel side mounting points when the mounting point is one point, but there are two vehicle body side mounting points such as A arm. In the case of, a straight line extending substantially in the vehicle width direction at right angles to the swing axis connecting the vehicle body-side attachment points is defined as the link axis. Next, according to a fifth aspect of the present invention, in contrast to the fourth aspect, the lower bush is configured by interposing an elastic body between an inner cylinder and an outer cylinder. In the upper and lower portions sandwiching the inner cylinder, a bead is formed, and at least a part or all of the bead located in the up and down direction intersecting with the axis of the lower bush or in the vicinity thereof has a small gap in the up and down direction. It is characterized by having been done.

In the case where the vertical gap is set to be small, the size of the gap is such that the elastic member on the inner ring side and the elastic member on the outer ring side do not come into contact with each other at the normal wheel stroke. When the input load becomes large, such as when a wheel rides on a curb, the size is set such that the inner ring-side elastic body and the outer ring-side elastic body abut on the gap.

[0012]

According to the first aspect of the present invention, the lower end of the shock absorber main body itself can be set to the minimum ground clearance by offsetting the lower attachment point from the axis of the shock absorber in the vehicle width direction. As a result, the height level of the upper part of the shock absorber can be set lower by that amount, the stroke amount of the shock absorber can be increased, and the riding comfort can be improved.

If the suspension link extends in the vehicle width direction, even if the shock absorber shaft and the mounting point below the shock absorber are offset in the vehicle width direction, the offset direction is the same. Of the suspension link, the torsion of the suspension link, which may be caused by a reaction force input from the shock absorber to the suspension link during a wheel stroke, is suppressed.

Further, by offsetting the mounting point, the degree of freedom in arranging the shock absorber with respect to the mounting point on the suspension link is improved. At this time, when the invention according to claim 2 is adopted, even if the position of the lower portion of the shock absorber main body in the vehicle width direction is the same, the mounting point to the suspension link approaches the wheel, so that the ratio of the lever of the shock absorber to the wheel stroke becomes 1 (See FIG. 2). By this. For example,
If the damping force of the shock absorber is the same, the damping force at the wheel end is improved compared to setting the mounting point of the lower part of the shock absorber on the axis of the shock absorber, contributing to improved riding comfort without increasing the mass It is possible to do. . According to the third aspect of the invention, the lower part of the shock absorber is arranged to intersect with the suspension link in a plan view,
Even if the shock absorber and the shock absorber lower mounting portion are offset, it is possible to prevent the exclusive space under the shock absorber from increasing.

[0015] Further, when the invention according to claim 4 is adopted,
The invention described in claims 1 to 3 can be realized. Also, due to the relationship between the shock absorber axis and the lower mounting point being offset, the lower part of the shock absorber fluctuates around the axis of the shock absorber with the wheel stroke, and the twist around the upper and lower axes is input to the lower bush, By setting the rigidity of the lower bush around the vertical axis to be high, it is possible to reduce the fluctuation of the lower portion of the shock absorber due to the wheel stroke. As a result, for example, even when the lower portion of the shock absorber is loosely inserted into the recess or the opening of the suspension link, it is not necessary to make the recess or the opening larger than necessary.

[0016] In addition, the suspension bushing caused by the wheel stroke causes twisting around the axis parallel to the link axis on the lower bush. By setting the rigidity around the axis parallel to the link axis low, the lower bushing is reduced. The swing of the shock absorber accompanying the swing of the link is allowed, and the increase in friction at the wheel end is suppressed.

If the rigidity of the lower bush in the vertical axis direction is low, the response of the shock absorber is delayed by an amount corresponding to the bending of the lower bush, and there is a concern that steering stability and riding comfort may be adversely affected. Such adverse effects can be prevented by setting the rigidity of the lower bush in the vertical axis direction to be high. At this time, by adopting the invention according to claim 5, it is possible to easily realize the rigidity characteristics of the lower bush.

In other words, by forming the curl above and below the inner cylinder, the rigidity of the elastic body in the upper and lower portions of the inner cylinder relative to the vehicle width as viewed from the vehicle front-rear direction is relatively small. It is set lower than the rigidity of the elastic body located in the direction. As a result, the rigidity is set to be high by resisting the elastic portion located in the vehicle width direction with respect to the twisting around the vertical axis, and the vertical portion is twisted around the axis parallel to the link axis. The rigidity is set low by resistance with the elastic body.

In addition, since the gap in the vertical direction is reduced with respect to the load in the vertical direction, even if the vertical section is provided with a curve, the gap between the inner and outer cylinders is slightly increased by the small gap. , The elastic body on the inner cylinder side and the elastic body on the outer cylinder side come into contact with each other to increase rigidity.

[0020]

Next, embodiments of the present invention will be described with reference to the drawings. Parts and the like similar to those in the above-described conventional example are denoted by the same reference numerals and described. FIG.
FIG. 3 is an exploded perspective view showing attachment of a lower portion of the shock absorber 2 to the lower arm 1 according to the present embodiment.

The basic configuration of the suspension device of the present embodiment will be described by taking as an example a configuration similar to that of FIG. 7, that is, a shock absorber support structure applied to a multi-link independent suspension rear suspension device. That is, the lower arm 1 extends in the vehicle width direction, its inner end (vehicle side) in the vehicle width direction is connected to the suspension member 4 so as to be able to swing up and down, and its outer end (wheel side) is connected to the suspension member 4. It is connected to the lower part of the knuckle spindle 5 so as to be able to swing up and down. For the sake of simplicity, it is assumed that the link axis S of the lower arm 1 is oriented in the vehicle width direction.

As shown in FIGS. 1 and 2, a shock absorber 2 is attached to a portion of the lower arm 1 on the wheel side.
The lower part is swingably connected via the lower bush 10,
The shock absorber 2 extends upward. Next, a support structure of the lower part of the shock absorber 2 to the lower arm 1 will be described.

A pair of bush brackets 14 protrude outwardly in the vehicle width direction (a direction parallel to the link axis S) from the lower side surface of the cylindrical body 2a constituting the shock absorber 2 main body. 14 are opposed in the vehicle front-rear direction (the direction orthogonal to the link axis S).
The outer cylinder 1 of the lower bush 10 is arranged at the tip of a pair of bush brackets 14 facing each other in the vehicle front-rear direction.
Two sides are fixed.

The lower bush 10 has an elastic body 13 interposed between an inner cylinder 11 and an outer cylinder 12 whose axes are oriented in the front-rear direction of the vehicle. And, by devising the lug 14 provided on the elastic body 13, the rigidity around the vertical axis Z and the vertical direction is large, and the rigidity around the axis in the vehicle width direction X is reduced. Specifically, as shown in FIG. 3 and FIG. 4, there is formed a circular pipe 14 extending in the circumferential direction at each of the upper and lower elastic portions 13 </ b> A with the inner cylinder 11 interposed therebetween. However, at the center in the circumferential direction, a pair of stopper projections in which the elastic body 13 on the inner cylinder 11 side protrudes in a mountain shape toward the outer cylinder 12 side in each of the beams 14 so as to reduce the vertical interval. The portions 13C are provided at symmetrical positions with respect to the bush axis direction.

By providing such a curl 14, as shown in FIG. 5, in response to a prying input about the vertical axis Z, there is no curl-free elastic portion 13 B located in the vehicle width direction.
Is set to have high rigidity by resistance. In addition, the torsion input around the axis X in the vehicle width direction is resisted by the elastic portions 13 </ b> A located above and below, but the rigidity is low due to the formation of the curb 14 at the position. Is set. Further, in response to the input of a load in the vertical direction, the protrusion 13C is brought into contact with the elastic body 13 on the outer cylinder 12 side, that is, by touching the stopper, so that the protrusion 13C is turned up and down.
Even if 4 is formed, the rigidity increases after the contact.

The lower arm 1 is shown in FIGS.
As shown in FIG. 3, an opening 15 through which a lower portion of the shock absorber 2 can be loosely inserted is formed in an upper plate portion which is a member having a substantially U-shaped cross section with an open lower side and constituting an upper surface. . A pair of link-side brackets 16 protrude upward at positions outside the opening 15 in the vehicle width direction in a state of facing the front and rear of the vehicle. The lower end of the shock absorber 2 is loosely inserted into the opening 15, and the inner cylinder 11 side of the lower bush 10 is fixed to the pair of link-side brackets 16 via mounting bolts (see FIGS. 2 and 6). ).

With the above configuration, as shown in FIG. 2, the mounting point K at the lower portion of the shock absorber 2 is set to be offset further outward in the vehicle width direction than the axis P of the shock absorber 2. As described above, the attachment point K to the lower arm 1 is set outward in the vehicle width direction from the position of the shock absorber 2, so that the arrangement of the lower portion of the shock absorber 2 in the vehicle width direction is the same, and the shock to the wheel stroke is reduced. The lever ratio of the absorber 2 can be set large. Here, conventionally, the lever ratio was (L1 / L2), but in the present embodiment, it is set to be large (L1 ′ / L2). As a result, when the damping force at the wheel end is constant, the diameter of the shock absorber 2 can be reduced,
The shock absorber 2 is lightweight, that is, the weight of the suspension is reduced. In addition, if the damping capacity of the shock absorber 2 is the same, the damping force at the wheel end increases,
This leads to improved riding comfort. Further, as the lever ratio increases, the load input from the upper portion of the shock absorber 2 to the vehicle body side member also decreases.

In this embodiment, the height of the lower end of the cylinder 2a of the shock absorber 2 is set to be substantially the same as the lower surface of the lower arm 1, that is, the minimum ground height. For this reason, even if the mounting height level of the upper part of the shock absorber 2 is the same, the stroke amount of the shock absorber 2 becomes large, and this also leads to improvement in riding comfort.
Conversely, when the stroke amount of the shock absorber 2 is constant, the height level of the upper portion of the shock absorber 2 can be set lower by the amount that the lower portion of the cylinder 2a is displaced downward, that is, the shock absorber 2 The amount of protrusion of the upper portion toward the living room is suppressed, and the degree of freedom of the living room space is improved, for example, the living room space is widened.

By setting the rigidity of the lower bush 10 as described above, the following operations and effects are produced. That is, the shaft of the shock absorber 2 and the mounting point K
The lower part of the shock absorber 2 fluctuates around the axis of the shock absorber 2 with the wheel stroke, and the lower bush 10
In this embodiment, as described above, since the rigidity around the vertical axis Z is set high, it is possible to reduce the fluctuation of the lower portion of the shock absorber 2 due to the wheel stroke. Becomes As a result, it is possible to prevent the opening 15 opening to the lower arm 1 from being made unnecessarily large in order to loosely insert the lower portion of the shock absorber 2. That is, since the opening provided in the lower arm 1 can be set to the minimum necessary size, even if the opening 15 is provided, the lower arm 1 can be restrained from lowering in rigidity.

Further, twisting of the suspension link accompanying the wheel stroke causes twisting around the axis extending in the vehicle width direction in the lower bush 10, but by setting the rigidity around the axis extending in the vehicle width direction low, Swing of the shock absorber 2 accompanying swing of the lower link is allowed, and increase in friction at the wheel end is suppressed.

If the rigidity of the lower bush 10 in the direction of the vertical axis Z is low, the response of the shock absorber 2 is delayed due to the bending time of the lower bush 10, and there is a concern that steering stability and riding comfort may be adversely affected. In the present invention, such an adverse effect can be prevented by setting the rigidity of the lower bush 10 in the vertical axis Z direction to be high. Here, in the above-described embodiment, the link axis S of the lower arm 1 is oriented in the vehicle width direction for simplicity, but when the link axis S is inclined in the vehicle front-rear direction from the vehicle width direction. The lower bush 10 may be offset from the shock absorber 2 in a direction parallel to the link axis S. Even in this case, when viewed from the vehicle longitudinal direction, the link axis S of the lower arm 1 extends in the vehicle width direction, and the lower arm 1 is offset in the vehicle width direction with respect to the axis of the shock absorber 2.

Also, the case where the lower arm 1 serving as a suspension link has only one attachment point on the vehicle body such as an I-arm is described as an example. good. In this case, the direction orthogonal to the swing axis connecting the vehicle body-side attachment points may be considered as the link axis. In addition, although a multi-link type suspension device is illustrated, the present invention is also applicable to mounting the shock absorber 2 in another type of suspension device.

In the above embodiment, the lower arm 1 is provided with the opening 15 for loosely inserting the lower portion of the shock absorber 2. However, the concave portion for loosely inserting the lower portion of the shock absorber 2 with respect to the upper surface of the lower arm 1. And the lower part of the shock absorber 2 may be inserted into the recess. Further, in the present embodiment, the axis P of the shock absorber 2 is set so as to intersect with the link axis S of the lower arm 1 or pass near the link axis S, but the present invention is not limited to this. For example, lower arm 1
, The lower arm 1 may be supported in a cantilever manner on the mounting bracket. In this case, the shock absorber 2 is arranged offset from the link axis S of the lower arm 1 in the vehicle longitudinal direction. However, in this case,
As compared with the case of the above-described embodiment, disadvantages such as an unnecessary torsion torque being input to the lower arm 1 along with the wheel stroke and a requirement to individually secure a space occupied by the lower portion of the shock absorber 2 are required. There is a point.

Further, in the above embodiment, the case where the lower arm 1 is disposed outward in the vehicle width direction with respect to the shock absorber 2 has been described as an example, but the lower arm 1 is disposed inwardly in the vehicle width direction with respect to the shock absorber 2. It may be arranged. Except for the effect of the lever ratio, the same effect as in the above embodiment can be obtained. Further, in the above-described embodiment, the adjustment of the rigidity characteristics of the lower bush 10 is realized by devising the shape of the horn 14, but is not limited thereto. For example, a material having lower rigidity than the elastic body 13 located in the vehicle width direction may be used as the elastic body 13 in the upper and lower portions with the inner cylinder 11 interposed therebetween, or a high rigidity steel may be used for the elastic body 13 located in the vehicle width direction. The rigidity of the elastic body 13 located in the vehicle width direction may be set to be relatively high by interposing a spacer made of a material such as a product. However, it is necessary to separately provide means for increasing the rigidity in the vertical direction.

Further, in the above embodiment, the link bush is protruded above the opening 15 so that the lower bush 10 is provided.
However, the lower bush 10 may be supported on a pair of left and right side walls of the lower arm 1.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a support structure of a lower part of a shock absorber according to an embodiment according to the present invention.

FIG. 2 is a diagram showing a relationship between a lower portion of a shock absorber and a lower arm according to an embodiment according to the present invention, as viewed from a vehicle front-rear direction.

FIG. 3 is a cross-sectional view showing a lower bush according to the embodiment according to the present invention.

FIG. 4 is a view taken in the direction of arrows AA in FIG. 3;

5A and 5B are diagrams for explaining the operation of the lower bush, in which FIG. 5A is a diagram viewed from the vehicle width direction, and FIG. 5B is a diagram viewed from the vehicle front-rear direction.

FIG. 6 is a view showing a relationship between an opening 15 of the lower arm 1 and a lower portion of the shock absorber.

FIG. 7 is a perspective view showing an example of a configuration of a suspension device.

FIG. 8 is a view for explaining a conventional support structure for a lower portion of a shock absorber.

9 is a view as viewed in the direction of arrows CC in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower arm (suspension link) 2 Shock absorber 2a Cylindrical body 10 Lower bush 11 Inner cylinder 12 Outer cylinder 13 Elastic body 13A Upper and lower part which sandwiched inner cylinder 13B Car width direction part which sandwiched inner cylinder 13C Protrusion for stopper 14 Shock absorber axis S Link axis X Vehicle width direction (axis parallel to link axis) Z Vertical axis K Lower mounting point

Claims (5)

[Claims] 1. A shock absorber supporting structure for supporting a lower portion of a shock absorber on a suspension link and extending the shock absorber upward, wherein a mounting point of the lower portion of the shock absorber to the suspension link is attached to a shaft of the shock absorber. A shock absorber support structure characterized by being offset in the vehicle width direction. 2. The shock absorber support structure according to claim 1, wherein a point of attachment to the suspension link is offset outward in a vehicle width direction with respect to an axis of the shock absorber. 3. The shock absorber support according to claim 1, wherein a lower end of the cylinder of the shock absorber is loosely inserted into a concave portion or an opening provided on an upper surface of the suspension link. Construction. 4. A suspension according to claim 1, wherein said suspension link extends in a vehicle width direction as viewed from a vehicle front-rear direction, and a lower bush is arranged offset from a lower side surface of said shock absorber in a link axis direction of said suspension link. By connecting the bush to the suspension link with the shaft oriented in a direction orthogonal or substantially orthogonal to the link axis, the lower part of the shock absorber is supported by the suspension link, and the lower bush reduces rigidity around the vertical axis. The shock absorber support structure according to any one of claims 1 to 3, wherein the rigidity around the axis parallel to the link axis is set low and the rigidity in the vertical axis direction is set high. 5. The lower bush has an elastic body interposed between an inner cylinder and an outer cylinder, and a curb is formed in upper and lower portions of the elastic body sandwiching the inner cylinder. 5. The shock absorber support according to claim 4, wherein a gap in the vertical direction is set to be small at least in part or all of the beam located in or near the vertical direction intersecting the axis of the lower bush. Construction.