JPH08156829A - Lower arm mounting structure for suspension - Google Patents

Abstract

PURPOSE: To perform easy change of a spring constant for a rubber bushing in accordance with the design specification of a suspension by properly assembling a subframe, a lower arm and other parts if there are somewhat errors in machining. CONSTITUTION: In a lower arm mounting structure for a suspension, a rubber bushing 3 for a lower arm 2 is laid on an area where bolt insertion holes 13a, 13b out of plural bolt insertion holes 13a-13d in a subframe 1 are formed, and the rubber bushing 3 is fastened together therewith by a bolt 5 to mount the subframe 1 on an automobile body. A hole 31 in the rubber bushing 3 is formed into a slit shape and the radial thickness of an elastic member provided between an inner cylinder to form the hole 31 in the rubber bushing 3 and an outer cylinder for the rubber bushing 3 is differentiated in size between the longitudinal direction and the cross direction of the slit hole 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension lower arm mounting structure, and more particularly to a suspension lower arm mounting structure for supporting a vehicle wheel mounted on a subframe bolted to a vehicle body. Regarding

[0002]

2. Description of the Related Art Conventionally, as a lower arm mounting structure of this type of suspension, there is a structure as shown in FIGS. 7 and 8, for example. That is, this conventional structure has a pair of left and right lower arms 2e, 2e for supporting the wheels W.
Is not directly attached to the automobile body 7, but is attached to the sub-frame 1e formed separately from the automobile body 7. In addition, the lower arm 2 is attached to the subframe 1e.
As means for attaching the e and 2e, two of the four bolt insertion holes 13A to 13D provided at the front and rear of the left and right side edge portions of the subframe 1e, which are located on the rear side of the vehicle body, are provided. A rubber bush 3e provided at one end of each of the lower arms 2e is arranged in an overlapping manner at the location where the bolt insertion holes 13A and 13B are formed, and the rubber bush 3e is fastened together with a bolt 5 for attaching the subframe 1e to the automobile body 7. Means were adopted.

Employing such co-fastening means is convenient because the number of bolt fastening points can be reduced. Further, in the above structure, since the lower arms 2e, 2e are attached to the subframe 1e, it is convenient when it is difficult to attach the lower arms 2e, 2e directly to the automobile body.

In the above structure, the subframe 1e
When not only the rubber bush 3e of the lower arm 2e is mounted on the lower arm 2e but also another bush 4 is mounted on the mounting portion 19 of the sub-frame 1e, the lower arm 2e is caused by a manufacturing error of the sub-frame 1e and the lower arm 2e. The mutual dimension L3 between the rubber bush 3e and the other bush 4 is equal to the bolt insertion hole 13A of the sub-frame 1e.
The dimension L4 between the centers of the mounting portion 19 and the mounting portion 19 may not match. This makes it impossible to properly attach the lower arm 2e to the subframe 1e. Further, in such a case, normally, it is possible to attach the lower arm 2e to the sub-frame 1e by forming the bolt insertion hole 13A in a long hole shape so as to have flexibility in attaching the lower arm 2e. In the co-tightening structure described above, the position of the bolt 5 is set at a specific position in relation to the automobile body 7. Therefore, even if the bolt insertion hole 13A is formed in a long hole shape, the lower arm 2e is not supported. Frame 1e
It is difficult to install it properly.

Therefore, in the prior art, in order to eliminate the above-mentioned problems, by using a bolt 5 having a diameter considerably smaller than the hole 36 of the rubber bush 3e, play between the bolt 5 and the hole 36 can be prevented. S is provided, and the play S is used to absorb the dimensional error of each part described above.

[0006]

However, in the above-mentioned conventional structure, the bolt 5 having a diameter smaller than the hole 36 of the rubber bush 3e is used as a means for providing flexibility in mounting the lower arm 2e. There is a certain limit to reducing the diameter of the bolt 5, and the bolt 5 and the hole 36
Play S with and cannot be so large. Therefore, in the related art, it is not possible to widen the width of the size capable of absorbing the processing size error of each part of the subframe 1e and the lower arm 2e, and when the size error of each part is large, it is difficult to properly assemble the lower arm 2e. There was a difficulty that

Further, as in the prior art, in the structure in which the bolt 5 is inserted in the hole 36 of the rubber bush 3e with play, it is difficult to securely fix the rubber bush 3e.
Therefore, there is also a drawback that the rubber bushings 3e are apt to be unduly rattled, and the rubber bushings 3e cannot exert an appropriate cushioning action.

Further, in the structure using the rubber bush 3e as described above, depending on the design specifications of the suspension,
In some cases, the spring constant of the elastic member 37 of the rubber bush 3e may be desired to be changed. However, in the prior art, in order to change the spring constant of the rubber bush 3e in this manner, no other effective means has been proposed in addition to what is called currant processing for removing a part of the elastic member 37. is there. Therefore, conventionally, the spring constant of the rubber bush 3e cannot be easily changed, which is inconvenient. Moreover, there is a problem that the endurance life of the elastic member 37 is shortened by performing the curring process.

The present invention has been devised under such circumstances, and even if there are some processing errors in the respective parts such as the subframe and the lower arm, the assembling of these parts can be performed. The challenge is to improve the manufacturability by making it possible to appropriately change the spring constant of the rubber bush according to the design specifications of the suspension.

[0010]

In order to solve the above problems, the present invention takes the following technical means.

That is, according to the present invention, bolt insertion holes are provided at a plurality of positions, at least two positions at the front and the rear, of the left and right side edges of the subframe bolted to the automobile body. A hole for a rubber bush provided at one end of the lower arm of the suspension is arranged in an overlapping manner at a part of the hole where the bolt insertion hole is formed, and this rubber bush is used for mounting the subframe to the vehicle body. A lower arm mounting structure for a suspension, which is fastened together with a subframe by bolts, wherein a hole portion of the rubber bush is formed in a long hole shape, and an inner cylinder forming the hole portion of the rubber bush and an outer cylinder of the rubber bush are formed. The thickness in the radial direction of the elastic member that is interposed between the holes is such that It is characterized in that it is set to different sizes in the.

[0012]

In the lower arm mounting structure of the suspension of the present invention, the rubber bush provided at one end of the lower arm has the elongated hole shape. Therefore, this rubber bush is different from the conventional one. Even if the bolt for tightening together with the subframe is not much smaller than the hole of this rubber bush, the lower arm can have play along the longitudinal direction of the long hole of this rubber bush. When the lower arm is assembled to the frame, it is possible to adjust the position of the lower arm with a large slide amount along the desired fixed direction.

Therefore, even when the processing dimensional error of each part such as the subframe and the lower arm is somewhat large,
It is possible to properly absorb these dimensional errors and obtain a special effect that the lower arm can be properly assembled to a desired accurate position with respect to the subframe.

Further, the hole portion of the rubber bush of the lower arm has a long hole shape, and as a means for changing the position of the lower arm, unlike the prior art, it is necessary to insert a bolt having a considerably small diameter into the hole portion of the rubber bush. However, it is not necessary to use a bolt having a diameter substantially the same as the inner diameter of the hole of the rubber bush in the lateral direction. Therefore, unlike the prior art, at least the play of the bolt in the lateral direction of the hole of the rubber bush can be eliminated, so that the rubber bush can be fixed securely. As a result, it is possible to obtain an advantage that the rubber bush can be appropriately prevented from being unduly rattled and the rubber bush can exhibit a sufficient cushioning action.

Further, in the present invention, the hole portion of the rubber bush of the lower arm is formed in a long hole shape, and is provided between the inner cylinder forming the hole portion of the rubber bush and the outer cylinder of the rubber bush. Since the radial thickness of the elastic member in the radial direction is different between the longitudinal direction and the lateral direction of the elongated hole portion, the spring constant of the elastic member of this rubber bush is different in each direction of the rubber bush. Will have different values. Therefore, the spring constant of the elastic member can be changed only by changing the mounting direction of the rubber bush, and unlike the conventional case, it is not necessary to subject the elastic member to so-called curring. Therefore, it is easy to change the spring constant, which is convenient for manufacturing the suspension, and it is possible to avoid that the endurance life of the elastic member is shortened by the gouging process, and the endurance life of the rubber bush can be made longer than before. The effect is also obtained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will be described below.
A specific description will be given with reference to the drawings.

FIG. 1 is a plan view showing an example of a lower arm mounting structure of a suspension according to the present invention, and FIG. 2 is an exploded perspective view thereof. In FIG. 1, in this lower arm mounting structure, an automobile body (not shown in FIGS. 1 and 2)
A pair of left and right lower arms 2 and 2 for supporting wheels are attached to both left and right sides of a subframe 1 which is formed separately from. Note that, in FIG. 1, the direction indicated by arrow A is the front side of the vehicle body.

Each of the lower arms 2 is provided with branch arm portions 22 and 23 which are bifurcated from a tip portion formed with a hole portion 21 for supporting a wheel. Of these, a branch arm portion 22 on the rear side is provided. A rubber bush 3 having a central axis in the vertical direction is provided at the end 22a of the. On the other hand, the end portion 23a of the branch arm portion 23 on the front side is provided with another bush 4 whose center axis extends in the vehicle front-rear direction.

FIG. 3 is a plan view of the rubber bush 3, and FIG.
Is a sectional view taken along line X1-X1. This rubber bush 3
Is a metal outer cylinder 30 to which the branch arm portion 22 of the lower arm 2 is connected, a metal inner cylinder 32 forming a hole 31 for inserting a bolt, and a space between the inner cylinder 32 and the outer cylinder 30. The elastic member 33 is provided so as to be interposed therebetween. As the elastic member 33, various rubbers such as natural rubber, styrene-butadiene rubber, butyl rubber, foamed urethane rubber can be adopted.

The inner cylinder 32 of the rubber bush 3 is not a mere columnar shape, but is formed in a hollow oval shape, whereby a hole portion 31 for inserting a bolt is formed in an elongated hole shape. Further, the hole 31 is set such that its longitudinal direction is along the vehicle body front-rear direction, for example. The elastic member 33 of the rubber bush 3 has the inner cylinder 32 formed in the shape of a hollow ellipse, so that the radial thickness thereof is not uniform at various places, and for example, the thickness S in the vehicle width direction is maximum. At the same time, the thickness S1 in the front-rear direction of the vehicle body is minimized.

In FIG. 1 and FIG. 2, bolt insertion holes 13a to 13d are vertically penetrated at two front and rear positions on both left and right side edge portions 1a and 1b of the sub-frame 1. These four bolt insertion holes 13a-
13d are used to mount the sub-frame 1 on the automobile body, but the two bolt insertion holes 13a and 13b on the rear side of the vehicle body are also used for mounting the rubber bush 3 of the lower arm 2 among these. Has been done.

That is, as shown in FIG. 2, mounting portions 10 and 10a for mounting the rubber bush 3 of the lower arm 2 are provided at the rear portion of the sub-frame 1, and the upper and lower portions which form these mounting portions 10 and 10a. The bolt insertion holes 13a, 1 are provided in the pair of bracket pieces 12a, 12b.
3b is pierced in series. However, of the two bolt insertion holes 13a and 13b, one of the bolt insertion holes 13a is a circular hole having substantially the same diameter as the bolt 5 inserted into the bolt insertion hole 13a. On the other hand, the other bolt insertion hole 13b is formed in an elongated hole shape in the vehicle width direction.

FIG. 5 is a sectional view taken along the line X2-X2 in FIG. 1, and FIG. 6 is a sectional view taken along the line X3-X3 in FIG. 1, both of which show the co-tightening structure of the subframe 1 and the rubber bush 3.
In each of these drawings, a bolt 5 is inserted through a series of bolt insertion holes 13a, 13a formed in the upper and lower bracket pieces 12a, 12b of the subframe 1, whereby the rear side of the subframe 1 is used for automobiles. It is attached to the lower surface of the body 7. In addition, the bracket piece 12
The rubber bush 3 of the lower arm 2 is arranged between a and 12b, and the rubber bush 3 is attached to the sub-frame 1 by inserting the bolt 5 into the hole 31 of the rubber bush 3.

In FIG. 2, the bush 4 attached to the other end 23a of the lower arm 2 is the subframe 1
Are rotatably supported by other mounting portions 11, 11 provided in front of the mounting portions 10, 10a. Each of these mounting portions 11 is constituted by, for example, bracket pieces 14 and 14 projectingly provided on both side surfaces of the subframe 1, and the bush 4 of the lower arm 2 is arranged between the bracket pieces 14 and 14. After that, the bolts 50 (or pins) are inserted in series through the through holes 15 and 15 of the bracket pieces 14 and 14 and the through hole 4a of the bush 4, so that the brackets 14 and 14 are attached.

Among the four bolt insertion holes 13a to 13d of the subframe 1, the two bolt insertion holes 13c and 13d on the front side of the vehicle body are circular holes having a diameter larger than that of the bolt 5a. Has been formed. In this embodiment,
The four bolt insertion holes 13a to 13d described above are
First, the drilling position of one bolt insertion hole 13a is determined, and then the drilling positions of the other three bolt insertion holes 13b to 13d are determined with reference to the bolt insertion hole 13a. In addition, the above-mentioned two bolt insertion holes 13c, 1
3d is not used for mounting the lower arm 2,
A bolt 5a is inserted from below into the bolt insertion holes c and 13d, and this portion is directly bolted to the automobile body 7.

In the lower arm mounting structure of the suspension having the above-described structure, the two bolt insertion holes 13a and 13b on the rear side of the subframe 1 have no play in the longitudinal direction of the vehicle body when the bolts are inserted therein. It is not formed. Therefore, in FIG. 2, the center-to-center distance L between the rubber bush 3 of the lower arm 2 and the other bush 4 which are fastened together by the bolts 5 that are inserted through the bolt insertion holes 13a and 13b are different from each other due to the machining error of each part. Due to this, the mounting portions 10, 11 (or 10 of the subframe 1)
a, 11) does not match the center-to-center distances La,
Originally, it is difficult to attach the lower arm 2.

However, since the hole portion 31 of the rubber bush 3 of the lower arm 2 has a long hole shape along the longitudinal direction of the vehicle body, when the lower arm 2 is attached to the sub-frame 1, positioning in the longitudinal direction of the vehicle body is performed. It is possible to have flexibility. Therefore, even if the dimensions L and La are slightly different from each other, the lower arm 2 can be properly attached to the subframe 1.

When the rubber bush 3 is attached, the bolt insertion holes 13a and 13b formed in the sub-frame 1 are formed to have the same diameter as the bolt 5 or a long hole elongated in one direction. It is just being done. Further, the hole portion 31 of the rubber bush 3 is also merely formed in a long hole shape. Therefore, unlike the case where the bolt 5 is inserted in a hole having a diameter that is considerably larger than that with a play, the tightening force of the bolt 5 is less likely to loosen, and the subframe 1 and the rubber bushing 3 are secured. It will be possible to secure the bolts.

Further, in the rubber bush 3, as described with reference to FIGS. 3 and 4, the thickness S of the elastic member 33 in the vehicle width direction is large. Therefore, there is also an advantage that the cushioning function when a force in the vehicle width direction acts on the lower arm 2 can be made excellent.

Although the bolt 5a is inserted into each of the bolt insertion holes 13c and 13d on the front side of the sub-frame 1, these bolt insertion holes 13c and 13d are formed to have a larger diameter than the bolt 5a. , Play is provided.
Therefore, even if the drilled positions of the bolt insertion holes 13c and 13d are slightly displaced from the corresponding bolt holes on the vehicle body 7 side, the amount of displacement is calculated as the amount of displacement of the bolt insertion holes 13c and 13d. It can be absorbed by play, and the subframe 1 can be properly attached to the automobile body 7. Further, one of the two bolt insertion holes 13a and 13b on the rear side is one of the bolt insertion holes 1
Since 3b is formed in a long hole shape along the vehicle width direction, when mounting the subframe 1 to the vehicle body 7, it is possible to increase the flexibility of positioning in the vehicle width direction.

In the above embodiment, when the subframe 1 is provided with four bolt insertion holes 13a to 13d in total, one bolt insertion hole 13a used for mounting the rubber bush 3 of the lower arm 2 is not provided. The bolt insertion holes 13 used for attaching the rubber bushing 3 are used as the positioning reference for the bolt insertion holes 13b to 13d.
Since a and 13b can be formed in the shape of a hole having the same diameter as the bolt 5 or a long hole, the advantage that the rattling of the rubber bush 3 can be thoroughly prevented is obtained. However, the present invention is not limited to this, and any bolt insertion hole may be used as a reference. Further, the specific number of bolt insertion holes is not limited, and a larger number of bolt insertion holes than those in the above embodiment may be provided in the subframe.

Further, in the above embodiment, the hole portion 31 of the rubber bush 3 is formed into a long hole shape along the longitudinal direction of the vehicle body,
Although the buffering action against the force in the vehicle width direction orthogonal to this is made excellent, the present invention is not limited to this. In the present invention, since the thickness of the elastic member 33 of the rubber bush 3 varies depending on the direction, the hole 3 of the rubber bush 3 is different.
It is possible to appropriately change and set the spring constant of the elastic member 33 of the rubber bush 3 by changing the longitudinal direction of 1 variously.

In addition, according to the present invention, the specific configurations of the respective parts such as the subframe 1 and the lower arm 2 are not limited to those in the above embodiment. The specific configuration of each of these parts can be changed in various ways.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a lower arm attachment structure of a suspension according to the present invention.

FIG. 2 is an exploded perspective view of a lower arm mounting structure of the suspension shown in FIG.

FIG. 3 is a plan view of a main part showing an example of a rubber bush provided on a lower arm.

FIG. 4 is an enlarged sectional view taken along line X1-X1 of FIG.

5 is an enlarged sectional view taken along line X2-X2 of FIG.

6 is an enlarged cross-sectional view taken along line X3-X3 of FIG.

FIG. 7 is a plan view showing an example of a conventional lower arm attachment structure of a suspension.

8 is an enlarged sectional view taken along line X4-X4 of FIG.

[Explanation of symbols]

 1 Sub-frame 1a, 1b Left and right side edges (of sub-frame) 2 Lower arm 3 Rubber bush 5 Bolt 7 Car body 13a to 13d Bolt insertion hole 30 Outer cylinder (rubber bush) 31 Hole (rubber bush) 32 Inner cylinder (rubber bush) 33) Elastic member

Claims (1)

[Claims] 1. Bolt insertion holes are provided at a plurality of positions, at least two at the front and the rear, on both left and right side edge portions of a subframe bolted to an automobile body, and among the plurality of bolt insertion holes. A hole for a rubber bush provided at one end of the lower arm of the suspension is arranged so as to overlap at a portion where the bolt insertion hole is formed, and the rubber bush is attached by a bolt for mounting the subframe to the automobile body. A suspension lower arm mounting structure that is fastened together with a subframe, wherein the hole of the rubber bush is formed in an elongated shape, and is formed between an inner cylinder forming the hole of the rubber bush and an outer cylinder of the rubber bush. The radial thickness of the elastic member interposed is different between the longitudinal direction and the lateral direction of the elongated hole portion. Characterized in that it is set to lower arm mounting structure of the suspension.