JP2013063744A - Suspension arm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension arm that is feasible at low cost by a simple structure while ensuring durability.SOLUTION: The suspension arm 10 is formed by a belt-like steel sheet being curved in the thickness direction at the middle part of the longitudinal direction, and one end thereof is bent in a circular pattern to constitute a first housing part 20 and the other end is bent in the circular pattern to constitute a second housing part 22. In addition, the suspension arm includes: a first arm member 16 provided so that the one end and the other end are positioned on a virtual reference line which connects a center of the first housing part 20 to a center of the second housing part 22 or above the virtual reference line; and a second arm member 18 that has a long body formed by the steel sheet being shorn or cut to be curved in the width direction, and in which a shape of one end edge of the body in the width direction is formed to be along one side surface of the first arm member 16 in the thickness direction. The first arm member 16 and the second arm member 18 are abutted against each other so that their width directions are perpendicular to each other, and are then welded along the abutment surface, thereby forming in a T-shape at a cross section.

Description

  The present invention relates to a suspension arm.

  Conventionally, a suspension arm such as an upper arm or a lower arm has been used as a link mechanism between a vehicle body and a wheel. One end of the suspension arm is connected to the vehicle body via a connecting member such as a bush, and the other end is connected to the wheel side via a connecting member such as a bush. In addition to handling stability as a link mechanism, these suspension arms have strength to avoid interference with other parts installed on the vehicle body and maintain durability, and manufacture them after realizing them. Cost reduction is required.

  As such a suspension arm, for example, an arm component piece obtained by slicing and cutting an extruded mold member (see, for example, Patent Document 1), the arm portion is positioned on the central body member and both sides thereof. A pair of reinforcing members or the like (see, for example, Patent Document 2), an intermediate portion of the upper link that is bent downward so as to avoid the side member, and a sub link that is fixed to ensure strength (for example, A variety of configurations have been proposed.

Japanese Patent Laid-Open No. 10-35235 Japanese Patent Laid-Open No. 3-56730 JP-A-8-132835

  However, the suspension arm described in Patent Document 1 is difficult to bend due to its manufacturing method, and it is difficult to avoid interference with other parts due to the shape of the arm itself. In addition, the cross-sectional width is the same throughout the arm portion and the bush mounting portion in order to employ extrusion, but the cross-sectional width is unnecessarily large even considering the fatigue strength of the arm portion, which is preferable from the viewpoint of weight reduction. Absent. Although it is conceivable to cut an extra portion in this regard, there is a problem that it is not practical because of an increase in manufacturing cost.

  Moreover, although the suspension arm described in Patent Document 2 is made of FRP and can realize light weight and high strength, there is room for improvement in terms of manufacturing cost because of a relatively complicated structure and a large number of parts. Furthermore, although the suspension arm described in Patent Document 3 can effectively prevent interference with other parts by forming a curved upper link, the entire suspension arm is enlarged and the structure is increased by arranging sub links in parallel. There is a problem that it becomes complicated.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a suspension arm that can be realized at a low cost with a simple configuration while ensuring durability.

  In order to solve the above-described problem, a suspension arm according to an aspect of the present invention has one end connected to the vehicle body side via a first connecting member and the other end connected to the wheel side via a second connecting member. A suspension arm, which is obtained by bending a strip-shaped steel plate in the thickness direction at an intermediate portion in the longitudinal direction thereof, one end portion of which is bent into an annular shape and accommodates a first connecting member. And the other end is bent into an annular shape to form a second accommodating portion that accommodates the second connecting member, and one end and the other end of each of the first accommodating portion and the second accommodating portion. A first arm member provided on or exceeding a virtual reference line connecting the center of the part, and a long main body obtained by bending or bending a steel plate in the width direction One of the width direction of the body The edge shape is along one side surface in the thickness direction of the first arm member, the one edge shape in the longitudinal direction of the main body is along the outer peripheral surface of the first housing portion, and the other edge shape in the longitudinal direction is the second housing portion. A second arm member formed along the outer peripheral surface of the first arm member, the first arm member and the second arm member are brought into contact with each other so that their width directions are orthogonal to each other, and along the contact surface It is formed in a T-shaped cross section by welding.

  According to this aspect, by bending the belt-shaped steel plate, the main body that is curved in the first arm member and the annular housing portions at both ends thereof can be integrally formed, so that they are joined separately. Stress concentration does not occur as in the case of Further, since the second arm member is welded to the first arm member so as to have a T-shaped cross section, the section modulus of the suspension arm is increased and sufficient strength is obtained, so that the durability can be ensured.

  Further, since it is obtained by welding two plate members of the first arm member and the second arm member, the number of parts is small, it can be realized simply and at low cost, and the overall weight can be reduced. . Furthermore, since both ends of the first arm member are provided on the virtual reference line connecting the center of the first housing part and the center of the second housing part or beyond the virtual reference line, the load along the virtual reference line is provided. The external force to be received can be received at each housing portion. As a result, it is possible to prevent an excessive shearing force from being applied to the welded portion between the first arm member and the second arm member, and it is possible to maintain the durability.

  According to the present invention, it is possible to provide a suspension arm that can be realized at a low cost with a simple configuration while ensuring durability.

It is a perspective view of a suspension arm concerning an embodiment. It is explanatory drawing which shows the manufacturing method of a suspension arm. It is explanatory drawing which shows one of the main structures of a suspension arm. It is explanatory drawing which illustrates the structure of the suspension arm concerning a comparative example.

  Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. FIG. 1 is a perspective view of a suspension arm according to an embodiment. The suspension arm 10 is applied to an automobile suspension device. The suspension arm 10 is connected to a vehicle body frame (not shown) via a bush 12 (corresponding to a “first connecting member”) at one end extending in the vehicle width direction, that is, on the vehicle body side, and is connected to the vehicle width direction outside, that is, the wheel The other end extending to the side is connected to a knuckle (not shown) via a bush 14 (corresponding to a “second connecting member”). Since the specific configuration of the suspension device, that is, the peripheral configuration of the suspension arm 10 is known, the description thereof is omitted.

  The suspension arm 10 is formed by joining the first arm member 16 and the second arm member 18 along the longitudinal direction. The first arm member 16 and the second arm member 18 are both obtained by forming a steel plate, assembled so as to be perpendicular to each other, and joined together by welding along the contact surface. The suspension arm 10 is curved so that the middle part in the longitudinal direction protrudes downward, and interference with the side member of the vehicle body is prevented.

  FIG. 2 is an explanatory view showing a method for manufacturing a suspension arm. FIG. 2 (A) shows a state before welding, and FIG. 2 (B) shows a state after welding. As shown in the upper part of FIG. 2A, the first arm member 16 is obtained by bending a strip-shaped steel plate in the thickness direction at the middle portion in the longitudinal direction. One end portion of the first arm member 16 is bent so as to be wound in an annular shape, and serves as a first accommodating portion 20 for accommodating the bush 12. On the other hand, the other end portion of the first arm member 16 is bent so as to be wound in an annular shape, thereby forming a second accommodating portion 22 for accommodating the bush 14.

  On the other hand, as shown in the lower part of FIG. 2A, the second arm member 18 is formed into a shape that is curved in the width direction by stamping (shearing) a steel plate in the thickness direction by pressing. The upper end surface (that is, one end edge in the width direction) of the second arm member 18 has a shape along the lower end surface (one side surface in the thickness direction) of the first arm member 16. In addition, one end surface (one end edge) in the longitudinal direction of the second arm member 18 is shaped along the outer peripheral surface of the first housing portion 20, and the other end surface (the other end edge) in the longitudinal direction is the second housing portion. The shape is along the outer peripheral surface 22. In the present embodiment, the second arm member 18 is manufactured by punching a steel plate, but the steel plate may be cut along the shape of the second arm member 18.

  And the 1st arm member 16 and the 2nd arm member 18 which were comprised in this way are made to contact | abut so that the mutual width direction may orthogonally cross. At this time, the upper end surface of the second arm member 18 and both end surfaces in the longitudinal direction are assembled along the center line in the width direction of the first arm member 16. Then, as shown in FIG. 2B, the suspension arm 10 is formed by performing welding W along the contact surfaces. Needless to say, the weld W is applied to both sides of the second arm member 18 in the thickness direction. With such a configuration, the suspension arm 10 has a T-shaped cross section so that sufficient rigidity and strength can be obtained.

  FIG. 3 is an explanatory diagram showing one of the main components of the suspension arm. FIG. 3A shows the overall configuration, and FIG. 3B shows an enlarged view of the A part. In the suspension arm 10 configured as described above, the cylindrical bush 12 is press-fitted into the first housing portion 20, and the cylindrical bush 14 is press-fit into the second housing portion 22. In the modified example, arc welding or the like may be employed instead of press-fitting.

  And in particular, with respect to the virtual reference line L that connects the center of the first storage unit 20 and the center of the second storage unit 22, the tip 20a of the first storage unit 20 is located above the virtual reference line L, Each container is wound so that the tip 22a of the second container 22 is positioned on the virtual reference line L.

  With the configuration described above, the suspension arm 10 can be realized at a low cost with a simple configuration while ensuring durability. That is, since the main body of the first arm member 16 and the first housing portion 20 and the second housing portion 22 are integrally formed by bending a strip-shaped steel plate, they are joined separately. Stress concentration does not occur. Further, since the second arm member 18 is welded to the first arm member 16 in a T-shaped cross section, the section modulus of the suspension arm 10 is increased and sufficient strength is obtained, so that the durability is ensured. Can do. In addition, since the suspension arm 10 is obtained by welding two plate members of the first arm member 16 and the second arm member 18, the number of parts is small, and the suspension arm 10 can be realized simply and at low cost, and the overall weight is low. Can also be realized.

  Furthermore, both ends of the first arm member 16, that is, the leading edges of the first housing portion 20 and the second housing portion 22 are provided on the virtual reference line L or above the virtual reference line L, whereby the first arm It is possible to prevent a shearing force from being applied to the welded portion W <b> 1 between the lower end surface of the member 16 and the upper end surface of the second arm member 18. In other words, the external force from the vehicle body or the wheel on the suspension arm 10 is dominated by the component F along the virtual reference line L that connects the center of the first storage portion 20 and the center of the second storage portion 22 that are the pivot points. Conceivable. In this regard, according to the configuration of the present embodiment, the external force component F transmitted from the bush 12 is received by the annular portion of the first housing portion 20, and thus directly acts as a shearing force on the joint surface of the welded portion W1. It is suppressed. That is, the fatigue strength of the welded portion is reduced particularly with respect to the shearing force along the joint surface, and since the generation of such a shearing force is suppressed, the durability of the suspension arm 10 as a whole can be maintained. .

  FIG. 4 is an explanatory view illustrating the configuration of a suspension arm according to a comparative example. FIG. 4A shows a first comparative example, and FIG. 4B shows a second comparative example. In addition, in each figure, about the structure substantially the same as the said embodiment, the same code | symbol is attached | subjected.

  The main body of the suspension arm 210 according to the first modification is configured only by the second arm member 18, and both ends in the longitudinal direction of the second arm member 18 are welded to the bush 12 and the bush 14, respectively. Even in such a configuration, since the intermediate portion of the second arm member 18 is curved, interference with a part 220 such as a side member provided on the vehicle body can be avoided.

  On the other hand, since the second arm member 18 receives the largest bending moment at the position of the cross section S most offset from the virtual reference line L, it is preferable to increase the height of the cross section S as much as possible. However, it is difficult to increase the cross section S upward from the viewpoint of avoiding interference with the component 220. On the other hand, when the cross section S is enlarged downward, the centroid is away from the imaginary reference line L, and the bending moment increases.

  Therefore, it is conceivable as one solution to improve the section modulus by joining the first arm member 216 like the suspension arm 212 according to the second modification. However, the suspension arm 212 is different from the suspension arm 10 of the embodiment in that the first arm member 216 is welded to the bush 12 and the bush 14 at both ends thereof. According to such a configuration, since the main body of the suspension arm 212 has a T-shaped cross section as in the embodiment, a relatively large strength can be ensured.

  However, since the weld length of the welded portion W2 between the first arm member 216 and the bush 12 and the bush 14 cannot be taken sufficiently, stress concentration occurs in the welded portion W2 when an external force is applied, and the fatigue strength is increased. It will be insufficient. In this regard, for example, a method of setting the discarded beads for welding by increasing the widths of the bushes 12 and 14 is conceivable. However, problems such as a problem in terms of space, an increase in mass, or an increase in welding costs. Remains. In other words, this embodiment has an advantage that the problems of the comparative example can be solved with a simple configuration.

  The present invention has been described above based on the embodiments. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Suspension arm, 12,14 bush, 16 1st arm member, 18 2nd arm member, 20 1st accommodating part, 22 2nd accommodating part.

Claims (1)

A suspension arm having one end connected to the vehicle body side via a first connecting member and the other end connected to the wheel side via a second connecting member;
It is obtained by bending a strip-shaped steel sheet in the thickness direction at the middle part in the longitudinal direction, one end of which is bent into an annular shape to constitute the first housing member that houses the first connecting member, and the like An end portion is bent into an annular shape to form a second accommodating portion that accommodates the second connecting member, and one end and the other end thereof are the center of the first accommodating portion and the center of the second accommodating portion, respectively. A first arm member provided on or exceeding the virtual reference line connecting
It has an elongate main body obtained by bending in the width direction by shearing or cutting a steel plate, and one end shape in the width direction of the main body is one side surface in the thickness direction of the first arm member And the other edge shape in the longitudinal direction of the main body is formed along the outer peripheral surface of the second housing portion. Two arm members;
The first arm member and the second arm member are brought into contact with each other so that their width directions are orthogonal to each other, and welding is performed along the contact surface to form a T-shaped cross section. Suspension arm featuring

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