Link member and rear suspension

Abstract

To provide a link member or the like capable of differentiating a displacement amount of one end of the link member according to a displacement direction.SOLUTION: A link member 1 interposed between a first member and a second member includes an arm portion 2, a connecting portion 3 provided at one end of the arm portion 2 and connected to the first member, a fixing portion 4 fixed to the second member, a joining end portion 5 provided at the other end of the arm portion 2 and disposed at a distance from the fixing portion 4, and an elastic body 6 interposed between the fixing portion 4 and the joining end portion 5. The curved surfaces have different radii R1 to R4 of the contours in the cross sections cut along two planes that pass through the center line along the longitudinal direction of the arm section 2 and are orthogonal to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a link member and a rear suspension. [Background technology]

[0002] As an example of a link member interposed between a first member and a second member to form a link mechanism, Patent Document 1 discloses a link member used in automobile suspensions, etc., which comprises a link body consisting of an arm portion and connecting portions provided at both ends of the arm portion, and a vibration-damping bushing held within a cylindrical holding portion provided at at least one of the connecting portions.

[0003] A vehicle's rear suspension changes the direction of the wheels so that they face inward in the turning direction relative to the vehicle's direction of travel, for example, to prevent the vehicle from spinning due to centrifugal force during braking turns. Specifically, the front and rear ends of the knuckles that rotatably support the rear wheels are connected to two lower arms made of link members. The front lower arm is short and the rear lower arm is long, and the attachment points of the lower arms on the wheel side are tilted rearward from the inside of the vehicle body, thereby changing the direction of the wheels by utilizing the difference in left-right displacement relative to forward-rear displacement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-95861 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because the lower arms of the above-mentioned rear suspension are short at the front and long at the rear, a difference in vertical displacement occurs, just as with front-to-rear displacement. For this reason, on rough or undulating roads, for example, the direction of the wheels changes every time the suspension strokes vertically to follow the road surface, reducing the vehicle's straight-line running performance. Thus, it is desirable for the link member interposed between the first member and the second member to constitute a link mechanism to have a different amount of displacement at one end of the link member depending on the direction of displacement.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a link member and a suspension that can vary the amount of displacement of one end of the link member depending on the direction of displacement. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a link member interposed between a first member and a second member, comprising an arm portion, a connecting portion provided at one end of the arm portion and connected to the first member, a fixed portion fixed to the second member, a joint end portion provided at the other end of the arm portion and spaced apart from the fixed portion, and an elastic body interposed between the fixed portion and the joint end, wherein the fixed portion and the joint end each have curved surfaces facing each other, and each curved surface has a different radius of contour in a cross section cut by two planes that pass through a center line along the longitudinal direction of the arm portion and are perpendicular to each other. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a link member and a suspension that can vary the amount of displacement of one end of the link member depending on the direction of displacement. Problems, configurations, and effects other than those described above will become clear from the description of the following embodiments. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 2 is a perspective view of a link member according to the embodiment. [Figure 2] FIG. 2 is a vertical cross-sectional view taken along a vertical plane of the link member according to the embodiment. [Figure 3] FIG. 2 is a horizontal cross-sectional view taken along a horizontal plane of the link member according to the embodiment. [Figure 4] FIG. 2 is a schematic diagram illustrating an elastic body. [Figure 5] 10 is a plan view illustrating displacement of a connecting portion when the link member is used as a front lower arm of a suspension. FIG. [Figure 6] 10 is a view seen from the rear of the vehicle for explaining displacement of a connecting portion when the link member is used as a front lower arm of a suspension. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, an example will be described in which the link member 1 according to the present invention is used as the front lower arm of two lower arms arranged at the front and rear to form a rear suspension that is provided between a knuckle that rotatably supports the rear wheel and a suspension member that is a vehicle body side member.

[0011] 1 to 3, the link member 1 has an arm portion 2, a connecting portion 3 provided at one end of the arm portion 2 in the longitudinal direction and connected to the knuckle, a fixed portion 4 fixed to the suspension member, a joint end portion 5 provided at the other end of the arm portion 2 in the longitudinal direction and arranged at a distance from the fixed portion 4, and an elastic body 6 interposed between the fixed portion 4 and the joint end portion 5.

[0012] The connecting portion 3 is a vibration-isolating bushing 3A provided at the end of the arm portion 2, and is inserted into a bolt on the knuckle side and tightened with a nut.

[0013] The fixed portion 4 has a fixed plate portion 4A that is screwed to the suspension member, and a curved portion 4B that has a curved surface that protrudes toward the opposite side of the suspension member at approximately the center of the fixed plate portion 4A. The curved surface of the curved portion 4B will be described later.

[0014] The joint end 5 is disposed opposite the curved portion 4B and has a curved surface that protrudes toward the arm portion 2. The arm portion 2 is provided at the center of the surface on the protruding side of the joint end 5. The curved surface of the joint end 5 will be described later.

[0015] As shown in Fig. 4, the elastic body 6 is a laminated body in which sheet-like rubber sheets 6A are stacked and bonded together. Each rubber sheet 6A is covered with a plurality of wires 6B arranged in a predetermined direction as the enclosed material, which are aligned in a direction perpendicular to the predetermined direction. Two overlapping and bonded rubber sheets 6A are stacked so that the wires 6B face in intersecting directions.

[0016] The elastic body 6 is bonded to the opposing surfaces of the fixing portion 4 and the joint end portion 5. Each wire 6B is flexible and has a higher elastic modulus than the rubber constituting the rubber sheet 6A. The enclosed material is not limited to the wire 6B, and can be any flexible material such as film or woven fabric that has a higher elastic modulus than rubber.

[0017] The arm portion 2 of the link member 1 is provided perpendicular to the fixed plate portion 4A and is located in the center between the fixed portion 4 and the joint end portion 5. Therefore, when the fixed portion 4 of the link member 1 is attached to a vertical surface, the arm portion 2 is positioned almost horizontally when no external force is acting on it.

[0018] In the following, the curved portion 4B and the curved surface of the joint end portion 5 will be described using the link member 1 in a state where the arm portion 2 is arranged horizontally as an example.

[0019] As shown in Figure 2, the outline of the curved surface of the curved portion 4B and the joint end 5 in a vertical cross section is a concentric arc centered at point Q, which is located at the end of an imaginary extension line L1 that extends the center line along the longitudinal direction of the arm portion 2 toward the fixed portion 4, and the radius R1 of the curved surface of the joint end 5 is longer than the radius R2 of the curved surface of the curved portion 4B by the thickness T1 of the elastic body 6 and the thickness T2 of the fixed portion 4.

[0020] As shown in Figure 3, the outline of the horizontal cross section at the center in the vertical direction (the most protruding position) of the curved surface of the curved portion 4B and the joint end 5 has a center O at the intersection of the imaginary extension line L1 and a line L2 horizontally connecting the suspension member side surface of the fixed portion 4, and the length connecting the center O to the vertex Q1 of the curved surface of the curved portion 4B or the vertex Q2 of the curved surface of the joint end 5 is the horizontal radius R3 of the curved portion 4B and the horizontal radius R4 of the joint end 5 at the center in the vertical direction, respectively.

[0021] The horizontal radius R4 of the joint end 5 is the same in the horizontal cross section at any height in the vertical direction of the joint end 5, and the horizontal radius R3 of the curved portion 4B varies in the vertical direction so as to be the distance between the imaginary vertical axis S (Figure 2) passing through the center O and the most protruding part of the curved portion 4B in the horizontal cross section at each height.

[0022] For example, at height H1, the bending portion 4B forms a curved surface such that a distance W1 between the apex (most protruding portion) P1 of the curved surface of the bending portion 4B in a horizontal cross section at height H1 and the imaginary vertical axis S is equal to a horizontal radius R3 of the bending portion 4B in the horizontal cross section at height H1, and at height H2, a distance W2 between the apex (most protruding portion) P2 of the curved surface of the bending portion 4B in a horizontal cross section at height H2 and the imaginary vertical axis S is equal to a horizontal radius R3 of the bending portion 4B in the horizontal cross section at height H2. Here, the vertical cross section and the horizontal cross section correspond to cross sections cut by two planes that pass through a center line along the longitudinal direction of the arm portion 2 and are perpendicular to each other.

[0023] 2 and 3, the radii R1 and R2 of the arcs that define the contours of the curved surfaces in a vertical cross section of the curved portion 4B and the joint end 5 are greater than the radii R3 and R4 that define the contours of the curved surfaces in a horizontal cross section. Therefore, when the connecting portion 3 is displaced in the vertical and horizontal directions, the amount by which the position of the connecting portion 3 moves toward the fixed portion 4 due to the tilt of the arm portion 2 relative to the position of the connecting portion 3 when the arm portion 2 is not tilted is greater when the connecting portion 3 is displaced in the horizontal direction than when the connecting portion 3 is displaced in the vertical direction.

[0024] Link member 1 is used as the front lower arm of two lower arms arranged at the front and rear of a rear suspension, and when the vehicle brakes to turn, for example, both link member 1 forming the front lower arm and rear lower arm 7 are displaced mainly horizontally so that connecting portions 3 and 8 move rearward, as shown in Figure 5. When link member 1 is displaced horizontally, it swings so as to follow the curved surface of curved portion 4B and joint end 5 in the horizontal cross section, and therefore the movement of connecting portion 3 is large due to the small swing radius.

[0025] In Figure 5, the center position of connecting portion 3 of link member 1 forming the front lower arm moves from A1 to A2, and the center position of connecting portion 8 connected to the knuckle in rear lower arm 7 moves from B1 to B2. At this time, the amount of movement of the center position of connecting portion 3 of link member 1 forming the front lower arm toward the vehicle body is greater than the amount of movement of the center position of connecting portion 8 of rear lower arm 7 toward the vehicle body. Therefore, the knuckle and wheel connected to connecting portions 3, 8 of link member 1 and rear lower arm 7 are tilted so that their front sides face toward the vehicle body, thereby suppressing external forces acting in a direction that would cause the vehicle to spin, thereby achieving stable driving.

[0026] On the other hand, when the wheel is displaced upward due to a rough road surface, both the link member 1 forming the front lower arm and the rear lower arm 7 are displaced mainly in the vertical direction so that the connecting portion 3 moves upward, as shown in Figure 6. When the link member 1 is displaced in the vertical direction, it swings along the curved surface of the curved portion 4B and the joint end 5 in the vertical cross section, so the swing radius is large and the movement of the connecting portion 3 is small.

[0027] In Figure 6, the center position of connecting portion 3 of link member 1 forming the front lower arm moves from A3 to A4, and the center position of connecting portion 8 of rear lower arm 7 moves from B3 to B4. At this time, the amount by which the center position of connecting portion 3 of link member 1 forming the front lower arm moves toward the vehicle body is approximately the same as the amount by which the center position of connecting portion 8 of rear lower arm 7 moves toward the vehicle body. Therefore, the knuckles and wheels connected to connecting portions 3, 8 of link member 1 and rear lower arm 7 are hardly tilted, ensuring excellent straight-line performance while following unevenness in the road surface.

[0028] According to the link member 1 of this embodiment, the fixed portion 4 and the joint end portion 5, which are joined via an elastic body 6, each have curved surfaces facing each other, and the cross sections cut by two planes that pass through the center line along the longitudinal direction of the arm portion 2 and are perpendicular to each other, for example, the contour radii R1 and R2 in the vertical cross section cut by the above-mentioned vertical plane and the contour radii R3 and R4 in the cross section cut by the horizontal cross section are different from each other.

[0029] Therefore, when the connecting portion 3 is displaced in one of the two mutually perpendicular directions, the connecting portion 3 is displaced due to the radii R1 and R2 of the curved surfaces of the fixing portion 4 and the joint end portion 5, and when the connecting portion 3 is displaced in the other direction, the connecting portion 3 is displaced due to the radii R3 and R4 of the curved surfaces of the fixing portion 4 and the joint end portion 5.

[0030] At this time, the radii R1 and R2 of the curved surface when the connecting part 3 is displaced in one direction are larger than the radii R3 and R4 of the curved surface when the connecting part 3 is displaced in the other direction, so the amount of movement of the connecting part 3 toward the fixed part 4 is reduced. In other words, it is possible to make the amount of movement of the connecting part 3 toward the fixed part 4 when the connecting part 3 is displaced different when the connecting part 3 is displaced in two perpendicular directions.

[0031] Furthermore, the elastic body 6 interposed between the fixed part 4 and the joint end part 5 has a rubber sheet 6A laminated in the axial direction of the arm part 2, which makes it less likely for rocking to occur, which occurs when one side in the swing direction of the arm part 2 is compressed more strongly than the other side. This allows the arm part 2 to swing more smoothly, allowing the connecting part 3 to be displaced to a stable position.

[0032] Furthermore, the rubber sheets 6A are covered with flexible wires 6B that have a higher elastic modulus than the rubber that makes up the rubber sheets 6A, so each rubber sheet 6A constituting each layer of the elastic body 6 is prone to shear deformation. This makes it possible to further suppress rocking and displace the connecting portion 3 to a stable position. Furthermore, the stacked rubber sheets 6A are arranged so that the two overlapping and joined rubber sheets 6A have their wires 6B oriented in a cross direction, further enabling the connecting portion 3 to be displaced to a stable position.

[0033] Furthermore, if the link member 1 is used as the front lower arm of the two lower arms that make up the rear suspension and is arranged so that the contour radii R1 and R2 of the curved surfaces of the fixed part 4 and the joint end 5 in the vertical cross section are larger than the contour radii R3 and R4 in the horizontal cross section, it is possible to make the amount of movement of the connecting part 3 toward the fixed part 4 when the connecting part 3 is displaced in the vertical direction smaller than the amount of movement of the connecting part 3 toward the fixed part 4 when the connecting part 3 is displaced in the horizontal direction.

[0034] For example, when the wheel is displaced upward due to unevenness of the road surface and the connecting part 3 of the link member 1 forming the front lower arm is displaced upward, the amount by which the connecting part 3 moves toward the fixed part 4 is smaller than the amount by which the connecting part 3 moves toward the fixed part 4 when the vehicle brakes and turns and the connecting part 3 of the link member 1 is displaced rearward.

[0035] Therefore, when the connecting part 3 is displaced upward, the inclination of the knuckle and wheel connected to the connecting part 3 relative to the straight-line direction is kept small, ensuring good straight-line running performance, and when the connecting part 3 is displaced horizontally, the knuckle and wheel are tilted relative to the straight-line direction, thereby suppressing external forces acting in the direction that causes the vehicle body to spin, thereby achieving stable running.

[0036] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention. The present invention covers all technical matters included in the technical ideas described in the claims. The above-described embodiments are preferred examples, but a person skilled in the art can realize various alternatives, modifications, variations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the appended claims.

[0037] In the above embodiment, an example has been described in which the link member 1 is arranged so that the radius of the arc that defines the contour of the curved surface of the curved portion 4B and the joint end portion 5 in a vertical cross section is larger than the radius that defines the contour of the curved surface in a horizontal cross section, but this is not limiting. For example, the link member 1 may be arranged so that the radius of the arc that defines the contour of the curved surface in a vertical cross section is smaller than the radius that defines the contour of the curved surface in a horizontal cross section. Furthermore, the link member 1 may be attached so that the longitudinal direction of the curved surface of the curved portion 4B of the fixing part 4 is not limited to being attached vertically or horizontally, and may also be attached and used in a state in which it is inclined at an angle. [Explanation of symbols]

[0038] 1: Link member 2: Arm section 3:Connection part 3A: Anti-vibration bushing 4: Fixed part 4A: Fixed plate part 4B: Curved section 5: Joint end 6: Elastic body 6A: Rubber sheet 6B: Wire rod 7: Lower arm 8:Connection part L1: Virtual extension line O: Center P1: The apex of the curved surface of the curved section in the horizontal cross section at height H1 P2: The apex of the curved surface of the curved section in the horizontal cross section at height H2 Q1: The apex of the curved surface of the curved part in the horizontal cross section Q2: Apex of the curved surface of the joint end in a horizontal section R1: Radius of the curved surface of the joint end cut by a vertical plane R2: Radius of the curved surface of the fixed part cut by a vertical plane R3: Radius of the curved surface of the fixing part cut on a horizontal plane R4: Radius of the curved surface of the joint end cut on a horizontal plane S: Virtual vertical axis T1: Thickness of elastic body T2: Thickness of the fixing part

Claims

1. A link member interposed between a first member and a second member, An arm portion; a connecting portion provided at one end of the arm portion and connected to the first member; a fixing portion fixed to the second member; a joint end portion provided at the other end of the arm portion and spaced apart from the fixing portion; an elastic body interposed between the fixing portion and the joining end portion; Equipped with The fixing portion and the joining end portion each have a curved surface facing each other, Each curved surface has a different radius of contour in a cross section cut by two planes that pass through a center line along the longitudinal direction of the arm portion and are perpendicular to each other. A link member characterized by:

2. The link member according to claim 1, The elastic body is formed by stacking sheet bodies in the axial direction of the arm portion. A link member characterized by:

3. The link member according to claim 2, The sheet body is formed from a flexible enclosed material and a rubber that covers the enclosed material and has a lower elastic modulus than the enclosed material. A link member characterized by:

4. The link member according to claim 3, the encapsulated material is a plurality of wires arranged along a predetermined direction and aligned in a direction intersecting the predetermined direction, The two sheets to be overlapped and joined together have wire directions that intersect with each other. A link member characterized by:

5. 2. A rear suspension using the link member according to claim 1, The cross sections cut by the two planes are a vertical cross section and a horizontal cross section, a radius of the contour in the vertical cross section is larger than a radius of the contour in the horizontal cross section; A rear suspension that is characterized by:

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