WO2018150665A1

WO2018150665A1 - Torsion beam component and torsion beam-type suspension

Info

Publication number: WO2018150665A1
Application number: PCT/JP2017/041306
Authority: WO
Inventors: 伊藤　泰弘; 嘉明中澤
Original assignee: 新日鐵住金株式会社
Priority date: 2017-02-16
Filing date: 2017-11-16
Publication date: 2018-08-23
Also published as: JPWO2018150665A1; JP6558507B2

Abstract

A torsion beam component (5) comprises one plate member, and is provided with: a torsion beam section (51) that is a first part of the plate member and extends in a vehicle-width direction; torsion beam side sections (52) that are each a second part of the plate member and extend from the ends of the torsion beam section (51) in a vehicle-length direction; and first flange sections (58) that are each a third part of the plate member and connect between the torsion beam section (51) and the torsion beam side sections (52).

Description

Torsion beam components and torsion beam suspension

The present invention relates to a torsion beam component and a torsion beam suspension.

Conventionally, a torsion beam type suspension has been adopted as a suspension for a rear wheel of an automobile such as a front wheel drive vehicle. The torsion beam type suspension includes a pair of torsion beam sides (also referred to as trailing arms) extending in the vehicle length direction of the vehicle body, and a torsion beam connecting between the torsion beam sides. A tire is rotatably attached to the torsion beam side. Further, a spring seat is provided inside the tire mounting position on the torsion beam side. A suspension spring, shock absorber, etc. are provided on the spring seat to absorb vibrations caused by vertical movement.
It is effective to reduce the unsprung weight to improve the motor performance. Unsprung weight reduction means weight reduction of parts under the spring of an automobile. Lightening parts include torsion beam sides and torsion beams. For this reason, the torsion beam side and the torsion beam are required to be thinner and stronger.

In general, the torsion beam and the torsion beam side are welded so that the torsion beam abuts against the side surface of the torsion beam side.
However, such a joining method has a problem that the welded portion is located at a corner where deformation is concentrated, and it is difficult to perform the construction. Further, such a joining method has a problem that fatigue fracture may occur from the welded portion when a torsional force acts on the torsion beam.

For this reason, as a method for joining the torsion beam and the torsion beam side, for example, in Patent Document 1 and Patent Document 2, the torsion beam joint is projected from the side surface of the torsion beam side in the vehicle width direction, and the torsion beam is welded to the torsion beam joint. A joining structure is disclosed.
According to the structures described in Patent Document 1 and Patent Document 2, it is possible to avoid the welded portion being positioned at the corner.
Patent Document 3 discloses a structure in which a gusset is disposed between a torsion beam side and a torsion beam, and the torsion beam side and the torsion beam are joined together by welding using the gusset.
According to the structure described in Patent Document 3, by using the gusset together, it is possible to suppress the deformation concentration on the welded portion and to improve the durability against torsional force.
Patent Document 4 discloses a trailing arm and a torsion beam which are formed by deep drawing a single metal plate. According to Patent Document 4, since there is no weld between the trailing arm and the torsion beam, the problem of fatigue failure between the trailing arm and the torsion beam can be solved.

JP 2014-213641 A Japanese Patent Laying-Open No. 2015-77937 JP 2012-101664 A Japanese Patent Laid-Open No. 8-127211

However, in the structures described in Patent Document 1 and Patent Document 2, since the welded portion is positioned on the torsion beam, it cannot be solved that the torsional force acts on the welded portion.
Moreover, since the technique described in Patent Document 3 uses a gusset, there is a problem that the number of parts is increased, and the unsprung weight cannot be reduced.
In Patent Document 1, Patent Document 2, and Patent Document 3, the torsion beam and the spring seat are separate parts. Patent Document 4 does not describe a spring seat. The vehicle body and the torsion beam suspension are connected by a suspension.
That is, a load is repeatedly applied to the spring seat while the automobile is traveling. The load concentrates on the joint between the spring seat and the torsion beam, which may cause fatigue failure. To reduce the weight of the torsion beam, if the torsion beam is increased in strength and thickness, welding becomes difficult and the load on the joint is concentrated.

An object of the present invention is to provide a torsion beam component and a torsion beam suspension in which a torsion beam and a torsion beam side can be made simple, and a fatigue failure is not easily generated in a spring seat portion.

The torsion beam component according to the first aspect of the present invention is composed of a single plate material, and is a first portion of the plate material, a torsion beam portion extending in the vehicle width direction, and a second portion of the plate material. A torsion beam side part extending in the vehicle length direction from an end of the torsion beam part, and a first flange part connecting the torsion beam part and the torsion beam side part, which is a third part of the plate member; Prepare.
Here, the torsion beam side part may be formed as a part of the torsion beam side, or may be the torsion beam side itself.

In the present invention, the spring seat portion can be formed using the first flange portion, and a load acting on the spring seat can be borne on the first flange portion. Therefore, even if a load is repeatedly applied to the spring seat portion, fatigue failure hardly occurs.

In the torsion beam component according to the second aspect of the present invention, the first flange portion is a spring seat portion.
By using the first flange portion itself as a spring seat, the torsion beam and the joint portion between the torsion beam side portion and the spring seat portion are eliminated, and fatigue failure is less likely to occur.

A torsion beam component according to a third aspect of the present invention includes a torsion beam side wall portion that is continuous with a side surface of the torsion beam portion, a torsion beam side top plate that is formed adjacent to the torsion beam side wall portion and is continuous with the top portion of the torsion beam portion. And a second flange portion facing the torsion beam side wall portion with the torsion beam side top plate portion interposed therebetween.
Since the torsion beam side part can be welded to the torsion beam side top plate part, the workability of the joining work by welding the torsion beam side part and the torsion beam side part is improved.

The cross section of the torsion beam side portion across the vehicle length direction becomes a groove shape by the second flange portion, and the groove shape shape extends in the vehicle length direction, so that the bending rigidity of the torsion beam side top plate portion can be improved. Further, since the second flange portion faces the torsion beam side wall portion, the second flange portion does not protrude outward in the vehicle width direction of the torsion beam side top plate portion. Therefore, the cross-sectional shape of the torsion beam side component to be joined can be increased, and the bending rigidity is further improved.

From the viewpoint of weight reduction and torsional rigidity of the torsion beam side portion, it is desirable that the second flange portion is located at the center in the width direction (for example, 25% to 75% in the width direction) of the closed cross section of the torsion beam side portion. If the allowance between the torsion beam side parts and the torsion beam part is large, the weight will increase. If the side of the part constituting the cross section of the torsion beam portion is long, the long side is easily bent.

A torsion beam suspension according to a first aspect of the present invention is the torsion beam part according to the first aspect, the torsion beam side part overlapped with the torsion beam side part, and a part of the torsion beam side part. And a spring seat portion superimposed on the flange portion.
If a 1st flange part is piled up on a spring seat part, a junction part can be expanded and both can be joined firmly. Therefore, even if a repetitive load acting on the spring seat portion is applied, stress concentration is relaxed, so that fatigue failure is less likely to occur.
Moreover, it can join by welding etc. in the overlapping part of a 1st flange part and a spring seat part, and workability | operativity also improves.

The torsion beam type suspension according to the second aspect of the present invention has the torsion beam component according to the third aspect and a cross-sectional groove shape, and one end surface of the groove shape is overlapped with the torsion beam side top plate portion, The other end surface of the groove shape includes a torsion beam side component superimposed on the first flange portion, and the second flange portion and the torsion beam side component are separated from each other.
Also according to the present invention, the same operation and effect as those described above can be enjoyed.

The perspective view which shows the structure of the torsion beam type suspension which concerns on embodiment of this invention. The perspective view which shows the structure of the components for torsion beams in the said embodiment. The perspective view which shows the state which combined the components for torsion beams and the components for torsion beam sides in the said embodiment. The principal part perspective view which shows the state which combined the components for torsion beams and the components for torsion beam sides in the said embodiment. The principal part perspective view which shows the modification of the state which combined the components for torsion beams, and the components for torsion beam side. The schematic diagram which shows the manufacturing method of the components for torsion beams in the said embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a torsion beam suspension 1 according to an embodiment of the present invention. The torsion beam suspension 1 is used as a suspension device for a rear wheel of a front-wheel drive automobile. The torsion beam suspension 1 includes a torsion beam side 2, a suspension spring 3, a shock absorber 4, a torsion beam component 5, and a spring seat portion 9. In the following description, the vehicle length direction of the vehicle body is F, the vehicle width direction of the vehicle body is W, and the vehicle height direction of the vehicle body is H.

The torsion beam side 2 includes a front arm 2A disposed on the front side of the vehicle body (not shown) and a rear arm 2B disposed on the rear side of the vehicle body with the torsion beam component 5 interposed therebetween.
The tip of the front arm 2A is attached to a vehicle body frame (not shown) via a bracket 6 so as to be rotatable about the vehicle width direction W as an axis. As a result, the front arm 2A is movable in the vehicle height direction H.
A wheel 7 is rotatably attached to the outer side surface of the rear end of the rear arm 2B. A lower end of the shock absorber 4 is attached to the inner side surface of the rear arm 2B via a bracket 8 so as to be rotatable about the vehicle width direction W of the torsion beam side 2. As a result, the rear arm 2B is movable in the vehicle length direction F.
A spring seat portion 9 is provided between the bottom surface of the rear arm 2 B of the torsion beam side 2 and the bottom surface of the torsion beam component 5, and the suspension spring 3 is provided on the top surface of the spring seat portion 9.

The suspension spring 3 is composed of a coil spring, and the shock absorber 4 is composed of a hydraulic cylinder composed of a piston rod and a cylinder.
The suspension spring 3 and the shock absorber 4 absorb the vibration applied to the wheel 7 in the vehicle height direction H, and relieve the vertical movement of the vehicle body.
Further, the difference in displacement in the vehicle height direction H of the pair of wheels 7 provided in the vehicle width direction W is absorbed by the twist of the torsion beam portion 51 (see FIG. 2) of the torsion beam component 5.

The torsion beam component 5 is a component constituting the torsion beam of the torsion beam suspension 1. As shown in FIG. 2, the torsion beam component 5 includes a torsion beam part 51, a torsion beam side part 52, and a first flange part 58.
The torsion beam portion 51 extends in the vehicle width direction W. The torsion beam side portion 52 extends in the vehicle length direction F from the end portion of the torsion beam portion 51.
The torsion beam part 51, the torsion beam side part 52, and the first flange part 58 are composed of a single plate material.

The torsion beam portion 51 as the first portion is made of an open cross-section material extending along the vehicle width direction W. In the present embodiment, the torsion beam portion 51 has a mountain shape in cross section perpendicular to the vehicle width direction W of the torsion beam portion 51. The top of the mountain shape is a ridge line 53, and the two oblique sides extending from the top of the mountain shape are inclined surfaces 54 that are inclined downward from the ridge line 53. The torsion beam portion 51 is manufactured by forming a steel plate with a press machine or the like. The thickness of the steel plate used for the torsion beam part 51 is set to 2.3 mm to 4.0 mm.

In the present embodiment, the torsion beam portion 51 has a mountain shape in cross section. The cross section of the member constituting the torsion beam portion is not limited to the chevron shape, and may be an open cross sectional shape such as a U-shaped cross section or a groove-shaped cross section. Moreover, although the lower end edge of the torsion beam part 51 is good also as a cutting process surface, you may form the folding | returning part bent inside the mountain shape. When the folded portion is formed, when the torsion beam portion 51 is twisted, stress is not concentrated on the processed end face, so that the fatigue strength is further improved.

The torsion beam side portion 52 as the second portion is integrally provided at both ends of the torsion beam portion 51 in the vehicle width direction W and extends in a direction intersecting the vehicle width direction W of the torsion beam portion 51 (vehicle length direction F). ing. The torsion beam side portion 52 includes a torsion beam side wall portion 55 and a torsion beam side top plate portion 56. The torsion beam side wall 55 extends in the vehicle height direction H of the vehicle body. The torsion beam side top plate portion 56 extends in the vehicle width direction W from the upper end of the torsion beam side wall portion 55.
The torsion beam side wall portion 55 and the torsion beam side top plate portion 56 are arranged in an L-shaped cross section.

The torsion beam side wall portion 55 is continuous with the inclined surface 54 of the torsion beam portion 51. A first flange portion 58 is formed adjacent to the lower end of the torsion beam side wall portion 55.
The first flange portion 58 that is the third portion is continuous with the lower end of the inclined surface 54 of the torsion beam portion 51.

The torsion beam side top plate portion 56 is formed adjacent to the upper end of the torsion beam side wall portion 55 and is connected to a ridge line 53 that becomes the top of the torsion beam portion 51. On the connection surface between the torsion beam side top plate portion 56 and the ridgeline 53, a concave portion 56A for improving the strength is formed.
A torsion beam side top plate 56 is hung from the width direction end of the torsion beam side top plate 56 in the vehicle height direction H, and sandwiches the torsion beam side top plate 56 from the width direction end of the torsion beam side top plate 56. A second flange portion 59 facing the portion 55 is formed.

As shown in FIG. 3, the torsion beam side component 21 constituting the torsion beam side 2 is joined to the outside of the torsion beam component 5 in the vehicle width direction W.
The torsion beam side component 21 is formed of a steel plate forming body having a groove shape that is larger than the cross section of the torsion beam side portion 52, and is joined so as to cover the torsion beam side portion 52 of the torsion beam side portion 5 from the outside. The thickness of the steel sheet used is 2.3 mm to 4.0 mm, similar to the torsion beam component 5.

The torsion beam side component 21 includes a wall portion 21A, a bottom flange portion 21B, and a top flange portion 21C. When the torsion beam side component 21 constitutes the torsion beam side 2, the wall portion 21 </ b> A extends in the vehicle height direction H. The bottom flange portion 21B is bent from the lower end of the wall portion 21A and extends inward in the vehicle width direction W. Similarly, the top flange portion 21C is bent from the upper end of the wall portion 21A and extends inward in the vehicle width direction W. The wall portion 21A, the bottom flange portion 21B, and the top flange portion 21C also extend in the vehicle length direction F.
The bottom surface of the first flange portion 58 of the torsion beam component 5 is overlaid on the top surface of the bottom surface flange portion 21B serving as one end surface.
The upper surface of the torsion beam side top plate portion 56 of the torsion beam component 5 is overlaid on the lower surface of the top surface flange portion 21C serving as the other end surface.
The second flange portion 59 of the torsion beam component 5 is disposed away from the wall portion 21 </ b> A of the torsion beam side component 21. The position of the second flange portion 59 is preferably the center in the cross-sectional width direction of the top surface flange portion 21C.

In a state where the torsion beam side component 21 is attached to the torsion beam component 5, the tip of the first flange portion 58 extends inward in the vehicle width direction W from the tip of the bottom flange portion 21B as shown in FIG. 4A. The extending portion 58 </ b> A may be provided, and the extending portion 58 </ b> A may be the spring seat portion 9.
As shown in FIG. 4B, the tip of the bottom flange portion 21B has an extension portion 21D that extends inward in the vehicle width direction W from the tip of the first flange portion 58, and this extension portion 21D is The spring seat portion 9 may be provided.
The inner end of the torsion beam side top plate portion 56 along the vehicle width direction W also protrudes in the vehicle width direction W by at least 5 mm from the tip of the top flange portion 21C.

As shown in FIGS. 4A and 4B, the torsion beam component 5 and the torsion beam side component 21 are exposed at the tip of the bottom flange portion 21B and the end portion of the overlapping portion of the first flange portion 58. May be joined by forming a welded portion Y2 by overlapping fillet welding along the end of the overlapping portion. Not limited to this, a hole may be formed in the first flange portion 58 and the bottom flange portion 21B of the overlapping portion, and mechanical joining such as screwing or riveting may be performed.
Further, the torsion beam component 5 and the torsion beam side component 21 are arranged such that the tip surface of the top flange portion 21C and the top surface of the torsion beam side top plate portion 56 are overlapped along the extending direction of the torsion beam side component 21. You may join by carrying out meat welding and forming the welding part Y1. Not limited to this, a hole may be made in the top surface flange portion 21C and the torsion beam side top plate portion 56 of the overlapping portion, and mechanical joining such as screwing or riveting may be performed. Alternatively, the overlapping portion may be joined with an adhesive.

Such a torsion beam component 5 can be manufactured, for example, by multistage pressing as shown in FIG.
First, a substantially H-shaped steel plate 5A in plan view is cut (blanked) by a press machine.
Using a predetermined mold, the ridgeline 53, the inclined surface 54 of the torsion beam portion 51, the torsion beam side wall portion 55 of the torsion beam side portion 52, the torsion beam side top plate portion 56, and the first flange portion 58 are pressed into the steel plate 5A.
Finally, the second flange portion 59 and the recessed portion 56A are pressed using a mold different from the first stage pressing.

According to this embodiment, there are the following effects.
To reduce the weight, if the plate thickness is reduced, welding becomes difficult and the welded portion becomes smaller, so there is a problem that loads are concentrated on the welded portion and are easily broken. In response to this problem, the first flange portion 58, the torsion beam side portion 52, and the torsion beam portion 51 are formed from a single plate material, and therefore the boundary between the first flange portion 58, the torsion beam side portion 52, and the torsion beam portion 51. With this, there is an effect that destruction is difficult to occur.

Further, the bent torsion beam side portion 52 is difficult to weld, and the welded portion that contributes to the joining tends to be small. This also causes the load to concentrate on the weld. In addition, when steel material is formed by hot pressing, aiming at high strength for weight reduction, there is a problem that the hot-pressed member is easily broken because the heat-affected zone becomes brittle or soft when welded. .
This problem often occurs in steel materials having a tensile strength after hot pressing of 1190 MPa or more. In order to reduce the weight of materials other than steel, aiming for higher strength and strengthening by precipitation strengthening of the aluminum alloy material, when welding the aluminum alloy, the welded part and the heat-affected zone are softened because the precipitates disappear due to the heat of welding. Therefore, it is easy to be destroyed. In this embodiment, as a result of using the first flange portion 58 or the torsion beam side component 21 joined to the first flange portion 58 as the spring seat portion 9, the spring seat portion 9 is not easily broken.

The secondary effects are as follows. The front end surface of the bottom flange portion 21B of the torsion beam side component 21 and the end of the overlapping portion of the first flange portion 58 of the torsion beam component 5, the front end surface of the top flange portion 21C and the torsion beam side top plate of the torsion beam component 5 It is possible to join by simply overlapping the end portion of the overlapping portion with the portion 56 and performing fillet welding. Since both have a relatively flat surface, the workability of the welding operation is improved. Moreover, since the number of parts is small, the process of joining parts can be reduced. Alternatively, these overlapping portions can be mechanically joined or joined with an adhesive. This is effective when the torsion beam component 5 is manufactured from a material that cannot be welded, such as CFRP (Carbon Fiber Reinforced Plastic).

Since the second flange portion 59 of the torsion beam component 5 is formed to face the torsion beam side wall portion 55, the bending rigidity of the torsion beam side portion 52 with respect to the force in the vehicle height direction H can be improved.
Further, by forming the second flange portion 59 so as to face the torsion beam side wall portion 55, a cross-sectional shape that does not protrude upward from the torsion beam side top plate portion 56 is obtained. Therefore, the torsion beam side part 52 can be covered from the outside by the torsion beam side component 21. Thereby, the cross section of the torsion beam side component 21 can be enlarged, and the bending rigidity with respect to the force in the vehicle height direction H of the torsion beam side component 21 by the ridge line between the second flange portion 59 and the torsion beam side top plate portion 56. Can be improved.
Further, it is desirable that the second flange portion 59 and the torsion beam side component 21 are separated from each other. This is because the ridgeline between the second flange portion 59 and the torsion beam side top plate portion 56 is not easily deformed, so that the connection between the torsion beam side top plate portion 56 and the torsion beam side component 21 is difficult to peel off.
The torsion beam part 5 and the torsion beam side part 21 are joined by welding at the torsion beam side part 52. Therefore, no welded portion is formed at the boundary between the torsion beam part 51 and the torsion beam side part 52, so that fatigue failure is unlikely to occur at the boundary between the torsion beam part 51 and the torsion beam side part 52.

In addition, this invention is not limited to embodiment mentioned above, The deformation | transformation as shown below is also included.
In the above-described embodiment, the torsion beam component 5 is manufactured by processing a steel plate, but the present invention is not limited to this. That is, the torsion beam component may be formed using a material such as aluminum, titanium, or FRP (Fiber Reinforced Plastic).
In addition, the specific structure and shape of the present invention may be other structures and the like as long as the object of the present invention can be achieved.

DESCRIPTION OF SYMBOLS 1 ... Torsion beam type suspension, 2 ... Torsion beam side, 2A ... Front side arm, 2B ... Rear side arm, 3 ... Suspension spring, 4 ... Shock absorber, 5 ... Parts for torsion beam, 5A ... Steel plate, 6 ... Bracket, 7 ... Wheel, DESCRIPTION OF SYMBOLS 8 ... Bracket, 9 ... Spring seat part, 21 ... Parts for torsion beam side, 21A ... Wall part, 21B ... Bottom flange part, 21C ... Top flange part, 21D ... Extension part, 51 ... Torsion beam part, 52 ... Torsion beam side , 53 ... ridge line, 54 ... inclined surface, 55 ... torsion beam side wall, 56 ... torsion beam side top plate, 56A ... recess, 58 ... first flange, 58A ... extension, 59 ... second flange.

Claims

Consists of a single plate,
A torsion beam portion extending in the vehicle width direction, which is the first portion of the plate material;
A torsion beam side part extending in the vehicle length direction from an end of the torsion beam part, which is the second part of the plate material;
A first flange portion connecting the torsion beam portion and the torsion beam side portion, which is a third portion of the plate member;
Parts for torsion beams.
The torsion beam component according to claim 1,
The first flange part is a torsion beam component which is a spring seat part.
The torsion beam component according to claim 1 or 2,
A torsion beam side wall continuous with a side surface of the torsion beam portion;
A torsion beam side top plate portion formed adjacent to the torsion beam side wall portion and continuing to the top of the torsion beam portion;
A torsion beam component comprising: a second flange portion facing the torsion beam side wall portion with the torsion beam side top plate portion interposed therebetween.
A torsion beam component according to claim 1;
A torsion beam side component superimposed on the torsion beam side part;
A spring seat portion that is a part of the torsion beam side component and is superimposed on the first flange portion;
Torsion beam suspension with
A torsion beam component according to claim 3,
A torsion beam side part that has a groove shape in cross section, and one end surface of the groove shape is overlapped with the torsion beam side top plate portion, and is overlapped with the first flange portion; and the second flange portion; A torsion beam suspension that is separated from the torsion beam side component.