JP3605534B2 - Torsion beam suspension - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is directed to an open section having an intermediate portion between a pair of left and right trailing arms that support a wheel at a rear end while a front end is pivotally supported by a vehicle body and that has an opening at a vehicle body front side or a vehicle body rear side extending in the vehicle body left and right direction. And a torsion beam type suspension connected to both ends of the torsion beam.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 10-236123 discloses a torsion beam type suspension provided with a torsion beam having an open cross section open at the front side of the vehicle body or at the rear side of the vehicle body. The torsion beam has a constant U-shaped cross section over the vehicle body left-right direction, the width of the upper plate constituting the upper surface thereof in the vehicle longitudinal direction, and the width of the lower plate constituting the lower surface thereof in the vehicle longitudinal direction. Are set the same.
[0003]
[Problems to be solved by the invention]
By the way, the height of the roll center of the vehicle provided with the torsion beam type suspension increases as the position of the torsion center at the center in the left-right direction of the torsion beam increases, and decreases as the position of the torsion center decreases. Therefore, the height of the torsion center of the torsion beam, that is, the height of the roll center of the vehicle is adjusted by forming the shape of the torsion beam as viewed from the vehicle front-rear direction into an arch shape in which the center in the left-right direction is curved vertically. be able to. However, because obstacles such as floor panels and exhaust pipes exist near the torsion beam, there is a limit to increasing the amount of bending of the torsion beam, and therefore, the amount of adjustment of the height of the torsion beam torsion center is also limited. was there. When the amount of bending of the torsion beam is increased, stress concentration occurs at the bending portion, which is disadvantageous in strength and weight.
[0004]
The present invention has been made in view of the above circumstances, and aims to increase the degree of freedom in setting suspension characteristics by adjusting the height of the torsion center of a torsion beam without depending on the curvature of the torsion beam. I do.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, the front end is pivotally supported by the vehicle body and the middle portion of the pair of left and right trailing arms that suspends wheels at the rear end is moved in the lateral direction of the vehicle body. In a torsion beam type suspension connected to both ends of an open-section torsion beam having an opening at a vehicle front side or a vehicle rear side, the torsion beam extends from the upper edge of the intermediate plate toward the opening. A plate, and a lower plate extending from the lower edge of the middle plate toward the opening, and the torsion center of the torsion beam is biased upward on the vehicle body center line with respect to the center of the thickness of the torsion beam. Therefore, the width of the upper plate in the vehicle longitudinal direction is gradually increased toward the vehicle center line, and the width of the lower plate in the vehicle longitudinal direction is gradually decreased toward the vehicle center line. Torsion beam suspension, characterized in that the width of the plate is larger than the width of the lower plate is proposed.
According to a second aspect of the present invention, in addition to the configuration of the first aspect, a torsion beam type suspension is proposed, wherein the thickness of the torsion beam is substantially constant in the lateral direction of the vehicle body. .
[0006]
According to the above configuration, in the torsion beam having an open section having an upper plate, a middle plate and a lower plate and having an opening on the front or rear side of the vehicle body, the width of the upper plate is gradually increased toward the vehicle body center line, and The width of the lower plate is gradually reduced toward the vehicle center line, and the width of the upper plate is made larger than that of the lower plate on the vehicle center line. The height of the torsion beam can be deviated upward, thereby preventing the torsion beam from interfering with the floor panel and the exhaust pipe, and also reducing the strength and weight of the torsion beam while increasing the degree of freedom in setting the suspension characteristics. Can be increased. Also, since the upper and lower plates of the torsion beam having an open cross section face the opening, the width of the upper and lower plates can be easily increased or decreased only by changing the trim lines of the upper and lower plates constituting the opening. The cost and time required for repairing the torsion beam can be reduced.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings. 1 to 5 show an embodiment of the present invention. FIG. 1 is a perspective view of the left half of a torsion beam type suspension of a rear wheel viewed from a diagonally rear side of a vehicle body, and FIG. 2 is a two-direction arrow of FIG. FIG. 3 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is a sectional view taken along line 4-4 of FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 of FIG.
[0008]
As shown in FIGS. 1 to 3, a torsion beam type suspension S for suspending rear wheels W, W of an automobile includes a pair of left and right trailing arms 11, which are formed of a pipe member bent gently and extend in the longitudinal direction of the vehicle body. Prepare. Each trailing arm 11 has a rubber bush joint 12 provided at a front end thereof supported by a bracket 13 on the vehicle body side so as to be able to swing up and down, and an axle fixed to a rear end of the trailing arm 11 via a bracket 14 in a lateral direction of the vehicle body. The rear wheel W is rotatably supported by 15. A lower end of a shock absorber 16 for attenuating the vertical swing of the trailing arm 11 is connected to a bracket 17 fixed to an intermediate portion of the trailing arm 11 in the front-rear direction. Further, the lower end of a suspension spring 18 that buffers a vertical impact input to the trailing arm 11 is supported by a spring seat 19 fixed to the rear end of the trailing arm 11. Right and left ends of a torsion beam 20 extending in the left-right direction of the vehicle body at a middle portion in the front-rear direction of the left and right trailing arms 11, 11 at positions sandwiched between the rubber bush joints 12, 12 and brackets 17, 17 of the shock absorbers 16, 16. Are connected by welding via the gussets 21 and 21, respectively.
[0009]
4 and 5, the torsion beam 20 symmetrical with respect to the vehicle body center line C1 is formed by pressing a single plate material into a U-shaped cross section, and has an opening at the rear side of the vehicle body. 20a are formed. The torsion beam 20 is located on the front side of the vehicle body and is inclined from the upper front to the lower rear side. The upper plate 20c extends horizontally from the upper edge of the intermediate plate 20b toward the rear of the vehicle, and the lower edge of the intermediate plate 20b. And a lower plate 20d extending horizontally toward the rear of the vehicle body. The front edge of the torsion beam 20 is a straight line in a plan view (see FIG. 2), and the torsion beam 20 is curved like a middle-high arch in a rear view (see FIG. 3).
[0010]
The width Wc of the upper plate 20c of the torsion beam 20 in the vehicle longitudinal direction and the width Wd of the lower plate 20d in the vehicle longitudinal direction change over the longitudinal direction of the torsion beam 20. As shown in FIG. 5, the width Wc of the upper plate 20c and the width Wd of the lower plate 20d are substantially equal at both left and right end portions of the torsion beam 20, but the width Wc of the upper plate 20c from there toward the vehicle body center line C1. Gradually increases, and the width Wd of the lower plate 20d gradually decreases. Therefore, as shown in FIG. 4, the width Wc of the upper plate 20c is larger than the width Wd of the lower plate 20d on the vehicle body center line C1. The widths Wc and Wd can be easily increased or decreased by changing the trim lines 20e and 20f of the upper plate 20c and the lower plate 20d when the torsion beam 20 is press-formed, so that the repair cost and the repair time can be reduced.
[0011]
When the widths Wc and Wd of the upper plate 20c and the lower plate 20d match, the torsion center C2 of the torsion beam 20 is located near the center C3 of the thickness of the torsion beam 20 in front of the middle plate 20b. However, due to the influence of the inclination and length of the middle plate 20b, the actual torsion center C2 is slightly shifted above the center C3 of the thickness of the torsion beam 20 (see FIG. 5). On the other hand, when the width Wc of the upper plate 20c is larger than the width Wd of the lower plate 20d, the torsion center C2 of the torsion beam 20 is larger than the center C3 of the thickness of the torsion beam 20 in front of the middle plate 20b. (See FIG. 4). In other words, the torsion center 20 of the torsion beam 20 is biased toward the side where the widths Wc and Wd of the upper plate 20c and the lower plate 20d are larger with respect to the center C3 of the thickness of the torsion beam 20.
[0012]
Thus, as shown in FIG. 3, the torsion center C2 is deviated toward the upper plate 20c having a large width Wc with respect to the center C3 of the thickness of the torsion beam 20 which is curved upwardly convex in a rear view. The deviation has reached α on the vehicle body center line C1. Therefore, even when the upward bending amount of the torsion beam 20 cannot be sufficiently secured due to interference with the floor panel, the width Wc of the upper plate 20c is set to be larger than the width Wd of the lower plate 20d, and the torsion beam 20 is not twisted. By moving the center C2 upward, the center of the roll is increased, and desired suspension characteristics can be obtained. In addition, since the torsion center C2 can be moved upward without increasing the amount of bending of the torsion beam 20, strong stress concentration occurs at the bending portion of the torsion beam 20, which is disadvantageous in strength and weight. Can be avoided.
[0013]
The embodiments of the present invention have been described above. However, various design changes can be made in the present invention without departing from the gist thereof.
[0014]
For example, the torsion beam 20 of the embodiment has a cross-sectional shape that is open at the rear side of the vehicle body, but may have a cross-sectional shape that is open at the front side of the vehicle body.
[0015]
Further, in the embodiment, the torsion beam 20 is curved convexly upward, but it may be curved linearly or convexly downward .
[0016]
The middle plate 20b does not necessarily have to have a flat portion.
[0017]
【The invention's effect】
As described above, according to the invention described in claim 1, in the torsion beam having an open cross section, which is constituted by the upper plate, the middle plate, and the lower plate and has an opening on the front or rear side of the vehicle body, the width of the upper plate Is gradually increased toward the vehicle body center line and the width of the lower plate is gradually reduced toward the vehicle body center line, so that the width of the upper plate becomes larger than that of the lower plate on the vehicle body center line. The height of the torsion center can be deviated upward without causing large torsion, which prevents the torsion beam from interfering with the floor panel and exhaust pipe, and also reduces the strength and weight of the torsion beam. Meanwhile, the degree of freedom in setting the suspension characteristics can be increased. Also, since the upper and lower plates of the torsion beam having an open cross section face the opening, the width of the upper and lower plates can be easily increased or decreased only by changing the trim lines of the upper and lower plates constituting the opening. The cost and time required for repairing the torsion beam can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view of a left half of a torsion beam type suspension of a rear wheel as viewed from an obliquely rear side of a vehicle body. FIG. 2 is a view in the direction of arrow 2 in FIG. 1. FIG. 3 is a view in the direction of arrow 3-3 in FIG. FIG. 4 is a sectional view taken along line 4-4 of FIG. 2; FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;
11 Trailing arm 20 Torsion beam 20a Opening 20b Middle plate 20c Upper plate 20d Lower plate W Rear wheel (wheel)
Wc Width of upper plate in longitudinal direction of vehicle body Wd Width of lower plate in longitudinal direction of vehicle body

Claims (2)

An intermediate portion between a pair of left and right trailing arms (11), whose front end is pivotally supported by the vehicle body and suspends wheels (W) at the rear end, extends in the left and right direction of the vehicle body and has an opening (20a) on the front side or rear side of the vehicle body. A torsion beam suspension connected to both ends of an open section torsion beam (20) having
The torsion beam (20) includes a middle plate (20b), an upper plate (20c) extending from an upper edge of the middle plate (20b) toward the opening (20a), and an opening extending from a lower edge of the middle plate (20b). A lower plate (20d) extending toward the portion (20a),
An upper plate (20c) for biasing the torsion center (C2) of the torsion beam (20) upward on the vehicle body center line (C1) with respect to the center (C3) of the thickness of the torsion beam (20). , The width (Wc) of the lower plate (20d) in the vehicle longitudinal direction is gradually decreased toward the vehicle center line (C1). A torsion beam type suspension wherein the width (Wc) of the upper plate (20c) is larger than the width (Wd) of the lower plate (20d) on the vehicle body center line (C1). The torsion beam type suspension according to claim 1, wherein the thickness of the torsion beam (20) is substantially constant in the lateral direction of the vehicle body.

Images