JP3196010B2 - Trailing arm - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a trailing arm which is a component of a trailing arm type suspension.

[0002]

2. Description of the Related Art An example of a trailing arm type suspension is shown in FIG.
In this prior art, both ends of a torsion beam 2e extending in the vehicle width direction are connected to a pair of left and right trailing arms 1e, 1e having a spindle shaft 12 for mounting wheels. At the front of the trailing arms 1e, 1e, bushes 11, 11 for attachment to the vehicle body are welded, and the attachment centers C1, C of these bushes 11, 11 are attached.
The entire body can swing up and down around 1. An opening 14e is formed in the inner side surface 1A of each trailing arm 1e in the vehicle width direction. After the end of the torsion beam 2e is inserted into the opening 14e, the opening 14e is formed. Is welded to the outer surface of the torsion beam 2e.

In such a trailing arm type suspension, if there is an input causing a vertical step between the two trailing arms 1e, 1e, the torsion beam 2e bends or twists due to the input. , To absorb the input.
However, the deformation of the torsion beam 2e alone has a certain limit in its function.

Therefore, conventionally, the trailing arm 1
e is formed so as to extend forward of the vehicle from the connection position of the torsion beam 2e, and the torsion beam 2 of the inner surface 1A of the trailing arm 1e is formed.
Also for the part on the vehicle front side from the insertion connection position of e,
As shown in FIG. 8, means having an open cross-sectional shape in which an opening 14e is formed at one end is employed. According to such means, the trailing arm 1e can be easily twisted and deformed, and can cope with a load input that cannot be coped with only by the deformation of the torsion beam 2e.

[0005]

However, in the prior art, as a means for easily twisting and deforming the trailing arm 1e, the inner surface 1 of the trailing arm 1e is simply used.
Since only the large opening 14e is formed in A, the following difficulties have occurred.

That is, in the above-described conventional trailing arm 1e, the rigidity of the portion where the opening 14e is formed is small, and when a bending force or a torsional force is generated in the torsion beam 2e, the opening 14e is closed. The formed part tends to be excessively twisted. For this reason, in the trailing arm 1e, when the torsional deformation occurs, stress concentration tends to occur in the connecting portion (welded portion) of the bush 11, particularly in the portion in the vehicle width direction indicated by the symbol A. Was. Therefore, conventionally, as means for increasing the connection strength of the bush 11, it has been necessary to form the connection portion considerably thicker or larger, which has been disadvantageous in terms of reducing the weight and size of the suspension.

In the suspension having the above structure, the width (opening height) of the opening 14e is required to insert the end of the torsion beam 2e into the opening 14e of the trailing arm 1e and to appropriately connect the two. It is necessary to strictly control the dimensions of H1. However, according to the above-mentioned conventional means, when the trailing arm 1e is manufactured by press molding, the wide area of the upper and lower wall members 80a, 80b of the trailing arm 1e, which is a general press surface, is formed with a predetermined width. It was necessary to finish to H1. Therefore, it has been difficult to finish the width of the opening 14e with high accuracy. Conventionally, the opening 14
Since the dimensional control of substantially the entire area of the upper and lower wall members 80a and 80b forming e must be strict, the manufacturing operation of the trailing arm 1e is complicated, and the manufacturing cost is expensive.

The present invention has been conceived under such circumstances, and makes it difficult to cause stress concentration on a specific portion of the trailing arm due to torsional deformation of the trailing arm. In addition, it is an object of the present invention to easily control the width of the opening.

[0009]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

That is, according to the present invention, a bush for attaching to a vehicle body is provided at a front portion, and an opening for inserting and connecting an end of a torsion beam is formed on an inner side surface in a vehicle width direction. A trailing arm, wherein the opening is formed in a shape extending from an insertion connection position of an end of the torsion beam to the mounting bush in front thereof, and both upper and lower edges of the opening; The portion is characterized by being subjected to a press working for forming each of these leading edges in a stepped or bent shape.

In the present invention, since the upper and lower edges of the opening of the trailing arm are press-formed to form their respective leading edges in a stepped or bent shape,
It is possible to increase the rigidity of the portion where the opening of the trailing arm is formed as compared with the conventional one that is not subjected to the above processing, and when bending or torsion occurs in the torsion beam, Thus, it is possible to suppress the trailing arm from being easily twisted by a large deformation amount. Therefore, according to the present invention, it is possible to alleviate the concentration of stress on the connecting portion of the bush due to the torsional deformation of the trailing arm, as much as the torsional deformation of the trailing arm can be suppressed. As a result, it is possible to increase the strength of the connecting portion of the bush of the trailing arm, and it is possible to effectively increase the suspension strength while avoiding an increase in the size and weight of the trailing arm. Can be

Of course, in the present invention, although the easy deformation of the trailing arm is suppressed, the opening for inserting and connecting the end of the torsion beam is provided at the insertion connection position of the end of the torsion beam as in the conventional case. Since it extends more forward than the vehicle, the location where this opening is formed can be appropriately twisted and deformed. Therefore, when a load input that cannot be dealt with only by deformation of the torsion beam occurs, it is possible to appropriately deal with the load input by the torsional action of the trailing arm, and there is no problem that the advantage of the related art is lost.

As a further important effect, in the present invention,
The dimension management of the width of the opening may be performed for each of the top edges formed in a stepped or bent shape at the upper and lower edges of the opening,
Unlike the related art, the width of the opening can be set to a predetermined size without managing a wide range of dimensions of the upper and lower wall members of the trailing arm. That is, in the present invention, it is possible to accurately set the width of the opening to a desired size as long as the dimensional accuracy of the pressed portion at the leading edge of the upper and lower edges of the trailing arm is secured. . Therefore, the dimensional control of the trailing arm is facilitated, and the manufacturing cost of the trailing arm can be reduced. Further, it is possible to reduce the possibility that the connection between the torsion beam and the trailing arm becomes difficult due to a dimensional error in the width of the opening. .

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a perspective view showing an example of a trailing arm 1 according to the present invention. FIG. 2 is a cross-sectional view of FIG.
It is X1 line sectional drawing. FIG. 3 is a plan view showing an example of a trailing arm type suspension configured using the trailing arm 1 shown in FIG. FIG. 4 is a cross-sectional view of a main part taken along line X2-X2 in FIG. FIG. 5 is a perspective view of a main part of the trailing arm type suspension shown in FIG. In FIG. 3, the direction of arrow N1 is the front of the vehicle, and the direction of arrow N2 is the vehicle width direction.

The trailing arm 1 shown in FIG. 1 includes an arm body 10, a bush 11 such as a rubber bush welded to the front of the arm body 10, a spindle 12 for mounting wheels, and the like. It is configured.
The trailing arm 1 is mounted on a vehicle body (not shown) so that the trailing arm 1 can swing up and down around a mounting center C of the bush 11.
It is for attaching to.

The arm main body 10 has a so-called monaka-like hollow shape in which an upper member 10a and a lower member 10b which are vertically divided into two parts are joined to each other.
The upper member 10a and the lower member 10b are formed by pressing (deep drawing) a metal plate having an appropriate thickness, and have a lower peripheral edge of the upper member 10a and an upper peripheral edge of the lower member 10b. Flanges 13a and 13b for connecting these to each other are appropriately formed.

An opening 14 through which the end of the torsion beam 2 can be inserted is formed in the inner side surface 1A of the arm body 10 in the vehicle width direction. As shown in FIG. 3, when the end of the torsion beam 2 is inserted into the opening 14 and the torsion beam 2 and the trailing arm 1 are connected to each other as shown in FIG. Open the torsion beam 2
Extend toward the vehicle front side from the insertion position of the end of the vehicle. Specifically, the opening 14 is formed over a relatively wide range from the insertion position of the end of the torsion beam 2 to the bush 11.

As shown in FIG. 2, the leading edges of the upper and lower edges 17a, 17b of the opening 14, that is, the edges of the upper and lower wall members 16a, 16b of the trailing arm 1,
A so-called baring process is performed by pressing, and stepped portions 18a and 18b that form a step having an appropriate dimension L are formed near the inside of the opening 14. These stepped portions 18a, 18b are formed in a series along the longitudinal direction of both upper and lower edges 17a, 17b of the opening 14.

As shown in FIG. 5, the arm body 10
A hole 15 for further inserting an end of the torsion beam 2 inserted into the opening 14 is provided in the outer side surface portion 1B in the vehicle width direction. The hole 15 is formed by bending a part of the flange 13a of the upper member 10a upward and bending a part of the flange 13b of the lower member 10b downward.
13b is formed so as to surround the outer periphery.

The trailing arm type suspension shown in FIG. 3 has a structure in which a pair of right and left trailing arms 1 and 1 having the above-described structure are connected by a torsion beam 2. As shown in FIG. 1, the torsion beam 2 has a substantially U-shaped cross section or a substantially V-shaped cross section that is open to the front of the vehicle, and has bending deformation and twisting with elasticity. The shape is relatively easy to deform.
The torsion beam 2 is formed, for example, by bending or bending a metal plate having a constant thickness.

Both ends of the torsion beam 2 are inserted at positions near the rear of the opening 14 of each trailing arm 1, and the distal end thereof is also inserted into the hole 15. 1 in the vehicle width direction. The torsion beam 2 is formed such that the width S2 of the portion to be inserted into the hole 15 is smaller than the width S1 of the portion to be inserted into the opening 14, so that the hole 15 is made as small as possible and the trailing Care is taken so that the strength of the arm 1 does not significantly decrease. As shown in FIG. 4, welding W1 is applied to the tips of the stepped portions 18a and 18b formed on the upper and lower edges 17a and 17b of the opening 14 and the outer surface of the torsion beam 2, and the hole Part 1
5 and the outer surface of the torsion beam 2 are welded W2
Is provided, whereby the trailing arm 1 and the torsion beam 2 are connected and fixed. Stepped portions 18a, 18 formed on the trailing arm 1
b is in surface contact with the outer surface of the torsion beam 2 so that the welding W1 can be appropriately performed on the inclined outer surface of the torsion beam 2.

Next, the trailing arm 1 having the above-described structure,
The operation of the trailing arm type suspension including the same will be described.

First, when manufacturing the above suspension, as described above, the end of the torsion beam 2 is inserted into the opening 14 of the trailing arm 1 and welded, as shown in FIG. The opening width H of the opening 14 is
It is defined by stepped portions 18a and 18b formed by press working. On the other hand, in the case of these stepped portions 18a and 18b formed in a narrow state, dimensional control by press working is easy, and dimensional accuracy can be improved.

Therefore, these stepped portions 18a, 18b
By increasing the dimensional accuracy between the openings 14
It becomes possible to insert the end of the torsion beam 2 into the inside in an appropriate fitting state, and it is possible to accurately connect the torsion beam 2 to the trailing arm 1. In forming the opening 14, processing of portions other than the step portions 18a and 18b may be relatively rough. Therefore, the manufacturing operation of the trailing arm 1 is also facilitated.

Next, in the above suspension,
When there is a load input that causes a vertical step between the pair of left and right trailing arms 1, 1, a bending force or a torsional force acts on the torsion beam 2, and this force is applied to each trailing arm 1. Also works. However, the upper and lower edges 17 of the opening 14 of each trailing arm 1
Since the stepped portions 18a and 18b are formed on the a and 17b, the rigidity of these portions is increased.
Is prevented from being excessively twisted around the welded portion of the bush 11. As a result, it is possible to eliminate or reduce the occurrence of stress concentration at the welded portion W3 of the bush 11 due to the large torsional deformation of the trailing arm 1.

When the applicant of the present invention conducted an experiment on stress concentration for the trailing arm type suspension having the above-described configuration, the following experimental results were obtained.

That is, as suspensions to be tested, two suspensions in which the dimensions and materials of the respective parts were set under the same conditions were produced, and one of them was the upper and lower edges 17a, 17a of the opening 14 of the trailing arm 1. 17
b according to the present invention in which stepped portions 18a and 18b are formed. For the other, the stepped portions 18a,
18b corresponds to a conventional example in which no 18b is formed.
Then, when a vehicle incorporating these two suspensions was driven under the same rough road conditions, the maximum stress generated at the connecting portion (portion A in FIG. 7) of the bush 11 was equivalent to that of the conventional example. It was 26 kgf / mm ² . On the other hand, in the case of the present invention, the maximum stress generated at the same location was 3.78 kgf / mm ² . Therefore, it can be seen from the experimental results that according to the present invention, the strength of the suspension arm 1 and, consequently, the strength of the entire suspension can be improved as compared with the related art.

On the other hand, the opening 14 is formed so as to extend toward the front of the vehicle from the position where the trailing arm 1 and the end of the torsion beam 2 are connected. It can be deformed. Therefore, when an input that cannot be dealt with only by the deformation of the torsion beam 2 acts on the suspension,
The formation of the opening 14 of the trailing arm 1 can be easily torsionally deformed to absorb or reduce the load applied to the suspension.

In the above embodiment, the torsion beam 2 penetrates through the inside of the trailing arm 1 in the vehicle width direction.
Because welding W1 and W2 are performed in each part of B,
Even if a bending force or a torsional force acts on the torsion beam 2 due to a vertical step between the left and right trailing arms 1, 1, this force is prevented from being concentrated on the position of the welding W 1. Is done. Therefore, the suspension has an advantage that the connection strength between the trailing arm 1 and the torsion beam 2 can be increased. However, the present invention is not limited to this. In the present invention, for example, the hole 15 may not be formed in the outer side surface 1 </ b> B of the trailing arm 1, and the end of the torsion beam 2 may be partially inserted into the trailing arm 1.

In the present invention, since the stepped portions 18a and 18b are formed at the upper and lower edges 17a and 17b of the opening 14 of the trailing arm 1, the stepped portions 18a and 18b are formed.
18b is brought into surface contact with the outer surface of the torsion beam 2 so that the torsion beam 2 and the trailing arm 1
Although the welding work with the above can be suitably performed, the present invention is not limited to this. In the present invention, the stepped portion 18
Needless to say, the specific shapes of the a and 18b are not limited to the above, and for example, as shown in FIG. A configuration may be adopted in which press working for forming the portions 18c and 18d is performed. With such a configuration, the rigidity of the location where the opening 14 is formed can be increased, and
The width H of the opening 14 can be defined to an accurate size by the bent portions 18c and 18d.

In addition, the specific structure of each part of the trailing arm according to the present invention is not limited to the above-described embodiment, and can be variously changed in design. Of course, the specific configuration of the torsion beam connected to this trailing arm does not matter.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a trailing arm according to the present invention.

FIG. 2 is a sectional view taken along line X1-X1 of FIG.

FIG. 3 is a plan view showing an example of a trailing arm type suspension configured using the trailing arm shown in FIG. 1;

FIG. 4 is a sectional view of a main part taken along line X2-X2 in FIG. 3;

FIG. 5 is a perspective view of a main part of the trailing arm type suspension shown in FIG. 3;

FIG. 6 is a sectional view showing another example of the trailing arm according to the present invention.

FIG. 7 is a plan view showing a conventional trailing arm suspension.

FIG. 8 is a sectional view taken along line X3-X3 in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Trailing arm 1A Inner side surface part 2 Torsion beam 11 Bush 14 Opening 17a, 17b Upper and lower edges 18a, 18b Stepped part 18c, 18d Bent part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-276942 (JP, A) JP-A 62-44709 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60G 7/00 B60G 9/04

Claims (1)

(57) [Claims] With 1. A mounting bush to the vehicle body is provided in the front, openings for inserting connecting ends of the torsion beam is formed on the inner surface in the vehicle width direction
A trailing arm, wherein the opening is an insertion connection of an end of the torsion beam.
From the position to the mounting bush in front of it.
Was formed into a shape, and the upper and lower edges of the opening, wherein the press working for forming the each of the end edges stepped or bent shape is applied, the trailing arm.