Automobile suspension system

Abstract

To provide a suspension device of an automobile which is a five-link suspension device with lower arms each supporting a lower end of each damper, capable of reducing sliding resistance while ensuring road clearance.SOLUTION: A suspension device of an automobile of the present invention includes: a lower arms 7 which connects a wheel support 10 and a vehicle body; and a damper 14 which is connected to the lower arm 7 at a lower end thereof, and arranged to be inclined upward and inward in a vehicle width direction in a rear view. A wall surface portion 100 of the lower arm 7 includes a damper attachment portion 98 for supporting a pivot portion 14a of the damper 14 at a position below a straight line (imaginary line A) connecting a pivot portion 70 on a wheel side of the lower arm 7 and a pivot portion 68 on a vehicle body side. A bottom surface portion 102 of the lower arm 7 is formed with a bulging portion 104 below the damper attachment portion 98.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a suspension device for an automobile, and more particularly to a multi-link rear wheel suspension consisting of five I-links. [Background technology]

[0002] Conventionally, a known multi-link suspension has five I-links (hereinafter referred to as "arms"), with the vehicle body end of each arm connected to the vehicle body and the wheel end of each arm connected to a wheel support (hub carrier) that supports the wheel. This type of multi-link suspension with five arms has high potential performance because it is possible to arrange each arm so that it optimally constrains the five degrees of freedom of movement, excluding the up and down stroke of the rear wheels, according to the requirements for each.

[0003] In recent years, in such multi-link suspensions, a configuration has been known in which the lower end of a damper, which is a shock-absorbing device, is connected to a lower arm out of the five arms (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special table number 2004-521826 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, in order to maximize the cushioning effect of the damper, it is desirable to minimize the inclination of the damper in order to match the load input direction with the displacement direction of the damper and reduce the sliding resistance. In other words, when the lower end of the damper is attached to the lower arm, it is preferable to make the attachment angle (inclination angle) of the damper as small as possible and close to the vertical direction in order to reduce the bending force applied to the damper when the lower arm moves up and down due to the vertical stroke of the wheel. However, when the lower end of the damper is attached to the lower arm, it is necessary to set the geometry of the lower arm and the damper after ensuring the road clearance of the lower arm, and there are layout restrictions on the attachment angle of the damper.

[0006] Therefore, the present invention has been made to solve the above-mentioned problems, and has an object to provide an automobile suspension device that can reduce sliding resistance while ensuring road clearance in a five-link suspension device in which the lower end of the damper is supported by a lower arm. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a wheel support that supports a wheel and has an opening in the center through which an axle passes, a trailing arm and a lower arm that connect a lower portion of the wheel support to a vehicle body, an upper arm and a leading arm that connect an upper portion of the wheel support to the vehicle body, and a control arm that connects a rear portion of the wheel support to the vehicle body; A shock absorber in which a coil spring and a damper are arranged coaxially, An upper end portion is connected to the vehicle body and a lower end portion is connected to the lower arm, Damper When viewed from the rear, the seat is tilted upward and inward in the vehicle width direction. shock absorberand a suspension device for an automobile comprising: a lower arm, an end portion of which on the vehicle body side is connected to the vehicle body via a pivot portion, and an end portion of which on the wheel side is connected to the wheel support via the pivot portion; a damper is connected to the lower arm via the pivot portion; the lower arm has a U-shaped cross section that is open upward and is formed by front and rear wall surface portions and a bottom surface portion extending in the longitudinal direction of the lower arm; Pivot Part and the pivot portion on the vehicle body side, and a bulge portion that bulges downwardly is formed on the bottom surface of the lower arm below the damper mounting portion so as to accommodate the pivot portion of the damper.

[0008] According to the present invention configured as described above, the front and rear wall surface portions of the lower arm have damper mounting portions that support the pivot portion of the damper at a position lower than a straight line connecting the pivot portion of the lower arm on the wheel side and the pivot portion on the vehicle body side, and a bulge portion that bulges downward to accommodate the pivot portion of the damper is formed on the bottom surface portion of the lower arm below the damper mounting portion. As a result, the inclination angle of the damper can be reduced in rear view by the amount that the damper mounting portion is set below the straight line connecting the pivot portion of the lower arm on the wheel side and the pivot portion on the vehicle body side. In other words, the inclination angle can be set so that the damper stands upright in the vertical direction. Therefore, in a five-link suspension device in which the lower end of the damper is supported by the lower arm, it is possible to reduce sliding resistance while ensuring road clearance.

[0009] In addition, in the present invention, preferably, each of the front and rear wall portions of the lower arm has a stabilizer link mounting portion at a position inward in the vehicle width direction from the damper mounting portion, and each of the front and rear wall portions of the lower arm is formed with a rib portion extending longitudinally at least from the damper mounting portion to the stabilizer link mounting portion. According to the present invention configured in this manner, the rib portion prevents deformation of the front and rear wall surfaces, thereby suppressing geometric changes in the damper mounting portion and the stabilizer link mounting portion. In other words, even if the area of ​​the wall surface is increased by setting the damper mounting portion below the straight line connecting the pivot portion on the wheel side of the lower arm and the pivot portion on the vehicle body side and forming the bulge portion, and the lower arm becomes more susceptible to deformation due to the increased area, the rib portion can prevent deformation of the front and rear wall surfaces. Effect of the Invention

[0010] According to the automobile suspension device of the present invention, in a five-link suspension device in which the lower end of the damper is supported by a lower arm, it is possible to reduce sliding resistance while ensuring road clearance. [Brief description of the drawings]

[0011] [Figure 1] 1 is a perspective view of a rear suspension assembly of an automobile to which an automobile suspension device according to an embodiment of the present invention is applied; [Diagram 2] FIG. 2 is a top view of the rear suspension assembly shown in FIG. [Diagram 3] FIG. 2 is a rear view of the rear suspension assembly shown in FIG. [Figure 4] FIG. 2 is a top view of the rear suspension on the left side of the vehicle according to the present embodiment. [Diagram 5] FIG. 5 is a left side view of the rear suspension of FIG. 4. [Figure 6] FIG. 5 is a front view of the rear suspension of FIG. [Figure 7] 5 is a view of the rear suspension of FIG. 4 as seen from the inside in the vehicle width direction. [Figure 8] FIG. 5 is a perspective view showing a lower arm of the rear suspension shown in FIG. 4 alone. [Figure 9] FIG. 5 is a plan view showing the lower arm of the rear suspension shown in FIG. 4 alone. [Figure 10]FIG. 5 is a rear view showing the lower arm of the rear suspension of FIG. 4 alone. [Figure 11] 4 is an enlarged rear view of the rear suspension on the left side of the vehicle of the rear suspension assembly shown in FIG. 3. [Figure 12] 5 is a partial cross-sectional side view seen from the outer side in the longitudinal direction of the lower arm, illustrating a damper mounting portion and a bulging portion in the lower arm of the rear suspension of FIG. 4. [Figure 13] FIG. 4 is a schematic diagram of a lower arm and a damper as viewed from the rear of the vehicle, for illustrating the effect of the mounting structure of the damper to the lower arm according to the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an automobile suspension device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the overall configuration of an automobile suspension device according to an embodiment of the present invention will be described with reference to Figures 1 to 3. Figures 1 to 3 show an embodiment in which an automobile rear wheel suspension device 1 (hereinafter simply referred to as a rear suspension) according to an embodiment of the present invention is applied to the rear wheels on both the left and right sides of an automobile, Figure 1 is a perspective view of an automobile rear suspension assembly to which the automobile suspension device according to the embodiment of the present invention is applied, Figure 2 is a top view of the rear suspension assembly shown in Figure 1, and Figure 3 is a rear view of the rear suspension assembly shown in Figure 1. The automobile (vehicle) of this embodiment is a rear-wheel drive vehicle having an engine mounted in an engine room at the front of the vehicle body (not shown), a differential disposed at the rear of the vehicle body, and rear wheels 2 driven by an axle (not shown). As shown in FIGS. 1 to 3, a rear suspension assembly of a rear wheel suspension device 1 includes a pair of left and right rear suspensions 1 and a subframe 3.

[0014] First, the general configuration of the rear suspension 1 will be described. The rear suspension 1 of this embodiment is of a multi-link type in which a wheel support (support member, hub carrier) 10 of the rear wheel 2 is connected to the vehicle body in a strokeable manner by five independent I-links 4 to 8. The suspension device 1 includes a front upper link (hereinafter referred to as "upper arm") 4 and a rear leading link (hereinafter referred to as "leading arm") 5 that virtually constitute an upper arm, a front trailing link (hereinafter referred to as "trailing arm") 6 and a rear lower link (hereinafter referred to as "lower arm") 7 that virtually constitute a lower arm, and a toe control link (hereinafter referred to as "toe control arm") 8 that regulates the rotational displacement of the rear wheel 2 around a virtual kingpin axis IK (see FIG. 5) described later. The upper arm 4, the leading arm 5, the trailing arm 6, and the lower arm 7 each swing up and down around a connecting portion (44, 52, 60, 68) on the vehicle body side, so that the wheel support 10 and the rear wheel 2 stroke up and down along a predetermined trajectory.

[0015] A shock absorber 16 is provided that includes a coil spring 12 and a damper 14 to allow such a stroke of the rear wheel 2 while at the same time applying a predetermined biasing force and damping force. The shock absorber 16 has a vertically long cylindrical shape in which the coil spring 12 and the damper 14 are arranged approximately coaxially, and its upper end is attached to the vehicle body. The lower end of the shock absorber 16 (the lower end of the damper 14) is pivotally attached to the lower arm 7. Further, a stabilizer bar 18 is rotatably attached to the suspension device 1 so as to extend so as to connect the left and right lower arms 7 together.

[0016] Next, a schematic configuration of the subframe 3 will be described. The subframe 3 is formed mainly by combining four steel plate components into a rectangular frame shape when viewed in a plane, and includes a front cross member 20 and a rear cross member 22 that extend in the vehicle width direction, and a pair of side cross members 24, 26 that extend in the fore-and-aft direction on both the left and right sides of the vehicle body so as to connect the left and right ends of the front and rear cross members together.

[0017] The front cross member 20 extends linearly in the vehicle width direction when viewed from above the vehicle, and both ends 20a in the vehicle width direction are joined to the front ends of the left and right side cross members 24, 26, respectively. When viewed in the vehicle longitudinal direction, the front cross member 20 is formed in an arch shape that is curved overall so that its longitudinal center portion is located higher than both the left and right ends. Furthermore, at both left and right ends of the front cross member 20, mounting seats 28 for the upper arm 4 and mounting seats 30 for the trailing arm 6 are provided, respectively, in positions close to the joints 20a with the side cross members 24, 26 and above and below the side cross members 24, 26 (see Figures 4 to 6). The vehicle body side end of the upper arm 4 is connected to the mounting seats 28 on both the left and right sides, and the vehicle body side end of the trailing arm 6 is connected to the mounting seats 30 on both the left and right sides.With this configuration, the front cross member 20 is able to withstand the lateral force transmitted from the wheels 2 via the arms 4, 6.

[0018] The rear cross member 22 extends linearly in the vehicle width direction when viewed from above the vehicle, and both ends 22a in the vehicle width direction are joined to the rear ends of the left and right side cross members 24, 26, respectively. As shown in Fig. 3, the rear cross member 22 is formed in an arch shape that is curved overall so that its longitudinal center portion is located lower than both the left and right ends when viewed in the vehicle front-rear direction. At both left and right ends of the rear cross member 22, a mounting seat 32 for the leading arm 5 and a mounting seat 34 for the lower arm 7 are provided, respectively, in positions close to the joints 22a with the side cross members 24, 26 and above and below the side cross members 24, 26 (see Figs. 4 and 5). The vehicle body side end of the leading arm 5 is connected to each of the mounting seats 32 on the left and right sides, and the vehicle body side end of the lower arm 7 is connected to each of the mounting seats 34 on the left and right sides.With this configuration, the rear cross member 22 receives the lateral force transmitted from the wheels 2 via each arm 5, 7.

[0019] Further, in top view, the rear cross member 22 is provided with mounting seats 36 for the toe control arms 8 on the inside in the vehicle width direction of each of the side cross members 24, 26 and on the rear side of the rear cross member 22. The vehicle body side ends of the toe control arms 8 are connected to the mounting seats 36 on both the left and right sides, respectively.

[0020] The left and right side cross members 24, 26 are each curved so that their longitudinal center portions are located inward in the vehicle width direction compared to both ends when viewed from above the vehicle, and extend obliquely downward toward the front of the vehicle from their rear ends to their front ends when viewed from the side (see FIG. 5). The above-mentioned mounting seats 28, 30 are provided in the front portions of these side cross members 24, 26, and the above-mentioned mounting seats 32, 34 are provided in the rear portions thereof.

[0021] Additionally, the side cross members 24, 26 are provided with elastic mounts 38, 40 for elastically supporting the entire subframe 3 on the vehicle body, and these elastic mounts 38, 40 are provided at a total of four locations, at the front and rear ends of each side cross member 24, 26. Each elastic mount 38, 40 has a cylindrical shape with an axis in the up-down direction, and is attached to a recess formed in each side cross member 24, 26. In each side cross member 24, 26, each elastic mount 38, 40 is disposed so that, when viewed from above the vehicle, a straight line connecting the elastic mount 38 at the front end and the elastic mount 40 at the rear end is substantially parallel to the center line CL (shown only in FIG. 2) in the fore-and-aft direction of the vehicle body.

[0022] Each elastic mount 38, 40 is formed with a predetermined gap called a "sugiri," and each elastic mount 38, 40 is formed so that its hardness (a characteristic indicated by the magnitude of the load (N) that produces a predetermined amount of deflection (mm)) differs in the front-to-back direction and the left-to-right direction relative to its axis. In this embodiment, each of the elastic mounts 38, 40 is attached to the side cross members 24, 26 so as to be oriented such that its stiffness in the vehicle width direction is greater than its stiffness in the vehicle front-rear direction. In addition, in this embodiment, the elastic mounts 38, 49 have different hardnesses, and the hardness of the elastic mount 38 at the front end in the fore-and-aft direction of the vehicle is set to be smaller (softer) than the hardness of the elastic mount 40 at the rear end in the fore-and-aft direction of the vehicle.

[0023] Next, the arrangement of the arms 4-8 of the rear suspension device 1 on the left side of the vehicle will be described with reference to Fig. 4 to Fig. 7. Fig. 4 is a top view of the rear suspension on the left side of the vehicle according to this embodiment, Fig. 5 is a left side view of the rear suspension in Fig. 4, Fig. 6 is a front view of the rear suspension in Fig. 4, and Fig. 7 is a view of the rear suspension in Fig. 4 as seen from the inside in the vehicle width direction. The rear suspension device 1 on the right side of the vehicle has the same configuration as the rear suspension 1 on the left side of the vehicle, so its description will be omitted below.

[0024] 4 to 6, the upper arm 4 has an end portion on the vehicle body side connected to the above-mentioned mounting seat 28 via an elastic bush (a rubber bush, hereinafter referred to as "bush") 42. The upper arm 4 extends with a rearward inclination so as to be gradually positioned rearward from a connecting portion 44 on the vehicle body side toward the outside in the vehicle width direction when viewed from above the vehicle. At a connecting portion 46 on the wheel 2 side, the end portion of the upper arm 4 on the wheel 2 side is connected to the wheel support 10 via a bush 48.

[0025] Next, the leading arm 5 has its end on the vehicle body side connected to the above-mentioned mounting seat 32 via a bush 50. When viewed from above the vehicle, the leading arm 5 extends with a forward inclination so as to be gradually positioned forward from the connecting part 52 on the vehicle body side toward the outside in the vehicle width direction. At the connecting part 54 on the wheel 2 side, the end of the leading arm 5 on the wheel 2 side is connected to the wheel support 10 via a bush 56.

[0026] In this manner, the two upper arms 4, 5 are disposed so as to approach each other toward the outside of the vehicle body when viewed from above the vehicle. In this embodiment, pillow ball joints are used for the bushes 42, 50 on the vehicle body side and the bushes 48, 56 on the wheel 2 side.

[0027] Next, the end of the trailing arm 6 on the vehicle body side is connected to the above-mentioned mounting seat 30 via a bush 58. When viewed from above the vehicle, the trailing arm 6 extends at a rearward inclination so that it is gradually positioned further rearward from a connecting part 60 on the vehicle body side toward the outside in the vehicle width direction. At a connecting part 62 on the wheel 2 side, the end of the trailing arm 6 on the wheel 2 side is connected to the wheel support 10 via a bush 64.

[0028] Next, the lower arm 7 has an end portion on the vehicle body side connected to the above-mentioned mounting seat 34 via a bush 66. The lower arm 7 extends with a forward inclination so as to be gradually positioned forward from a connecting portion 68 on the vehicle body side toward the outside in the vehicle width direction when viewed from above the vehicle. At a connecting portion 70 on the wheel 2 side, the end portion of the trailing arm 6 on the wheel 2 side is connected to the wheel support 10 via a bush 72.

[0029] In this way, the two lower arms 6, 7 are arranged so as to approach each other outward in the vehicle width direction when viewed from above the vehicle, and mainly due to this arrangement, a geometric toe-in is imparted to the rear wheels 2 as they are displaced toward the rear of the vehicle (longitudinal force compliance steer). That is, for example, when a braking force from the road surface acts on the rear wheels 2 during braking (when a force acting toward the rear of the vehicle is applied), the two lower arms 6, 7 are slightly pivotally displaced about the ends on the vehicle body side due to the bending of the bushes 56, 64, respectively, and as a result, the alignment of the rear wheels 2 changes to the toe-in direction. Furthermore, when a lateral force is applied to the wheel 2 during turning, the bushes 56, 64 of the lower arms 6, 7 are primarily deflected, causing the wheel 2 to change to a toe-in direction (lateral force compliance steer). In this embodiment, pillow ball joints are used for the bushes 58, 66 on the vehicle body side and the bushes 64, 72 on the wheel 2 side.

[0030] Next, the toe control arm 8 has its end on the vehicle body side connected to the above-mentioned mounting seat 36 via a bush 74. When viewed from above the vehicle, the toe control arm 8 extends with a forward inclination so as to be gradually positioned forward from a connecting portion 76 on the vehicle body side toward the outside in the vehicle width direction. At a connecting portion 78 on the wheel 2 side, the end of the trailing arm 6 on the wheel 2 side is connected to the wheel support 10 via a bush 80. In this embodiment, a pillow ball joint is used for the bush 74 on the vehicle body side and the bush 80 on the wheel 2 side.

[0031] 4 to 6, a virtual kingpin axis IK is formed in the rear suspension 1, vertically connecting an intersection P1 between an imaginary extension line of the upper arm 4 and an imaginary extension line of the leading arm 5, and an intersection P2 between an imaginary extension line of the trailing arm 6 and an imaginary extension line of the lower arm 7. This imaginary kingpin axis is the instantaneous rotation center of the rear wheel 2 in the steering direction (toe direction).

[0032] Next, the configuration of the wheel support 10 and the mounting configuration of each arm will be described with reference to Figs. First, as shown in FIGS. 4 to 7, the wheel support 10 has a hub 82 attached to its center, and is formed with an opening 84 through which an axle (not shown) passes. Further, the wheel support 10 is formed with a front vertical wall portion (arm mounting reinforcement portion) 86 that protrudes inward in the vehicle width direction at a portion forward of the opening 84 (portion forward of the axle), and the upper arm 4, leading arm 5 and trailing arm 6 are connected to this front vertical wall portion 86. That is, the respective connecting portions 44, 54, 62 and bushes 48, 56, 64 on the wheel 2 side of the upper arm 4, leading arm 5 and trailing arm 6 described above are provided on this front vertical wall portion 86. As shown in FIG. 6, a reinforcing rib 86a is formed on the outer edge of this front vertical wall portion 86.

[0033] Further, the wheel support 10 is formed with a lower vertical wall portion (arm mounting reinforcement portion) 88 that protrudes inward in the vehicle width direction at a lower portion of the opening 84, and the lower arm 7 is connected to this lower vertical wall portion 88. That is, the above-mentioned connecting portion 70 and bush 72 on the wheel 2 side of the lower arm 7 are provided on this lower vertical wall portion 88.

[0034] Further, the wheel support 10 has a rear vertical wall portion (arm mounting reinforcement portion) 90 that protrudes inward in the vehicle width direction in a portion rearward of the opening 84 (portion rearward of the axle), and the toe control arm 8 is connected to this rear vertical wall portion 90. That is, the above-mentioned connecting portion 78 and bush 80 on the wheel 2 side of the toe control arm 8 are provided on this rear vertical wall portion 90.

[0035] Next, the configuration of the lower arm 7 will be described with reference to Figures 8 to 10. Figure 8 is a perspective view showing the lower arm of the rear suspension of Figure 4 alone, Figure 9 is a plan view showing the lower arm of the rear suspension of Figure 4 alone, and Figure 10 is a rear view showing the lower arm of the rear suspension of Figure 4 alone. First, as shown in Figures 8 to 10, a vehicle body side mounting portion 92 is provided at one end in the longitudinal direction of the lower arm 7, and a bush 66 (see Figure 11) is attached to this vehicle body side mounting portion 92. The vehicle body side mounting portion 92 is attached to the mounting seat 34 of the above-mentioned side cross member 24 (26) via this bush 66. A wheel side mounting portion 94 is provided on the other longitudinal end of the lower arm, and a bushing 72 (see FIG. 11) is attached to this wheel side mounting portion 94. The wheel side mounting portion 94 is attached to the wheel support 10 at the connecting portion 70 via this bushing 72.

[0036] Further, at the longitudinal center of the lower arm 7, there is provided a stabilizer link attachment portion 96 to which stabilizer links 18a (see Figs. 3 and 11) provided at both ends of a stabilizer bar (stabilizer link) 18 are attached. In addition, a damper mounting portion 98 is provided between the wheel side mounting portion 94 and the stabilizer link mounting portion 96 in the longitudinal direction of the lower arm 7, and the lower end portion of the damper 14 of the shock absorber 16 is attached to this damper mounting portion 98.

[0037] The lower arm 7 has wall portions 100 formed opposite each other in the fore-and-aft direction, which is a direction perpendicular to its longitudinal direction, and a bottom portion 102 extending to connect these wall portions 100. The wall portions 100 and the bottom portion 102 give the lower arm 7 a U-shaped cross-section that is open upward. The opposing front and rear wall portions 100 are provided with the bolt-shaped mounting portions 92, 94, 96, 98 described above, as shown in the figure.

[0038] Also, a bulging portion 104 that bulges downward is formed at a position below the damper mounting portion 98 on the bottom surface portion 102 of the lower arm 7. Also, as shown in FIG. 10 in particular, the portion 100a on the front and rear wall surface portions 100 where the damper mounting portion 98 is provided is formed to have a longer vertical length than other portions in accordance with the shape of the bulging portion 104. That is, as shown in FIG. 10, when viewed in the front-rear direction, the upper edge portion (upper edge portion of the wall surface portion 100) 100b of the lower arm 7 extends in a substantially straight line from the vehicle body side mounting portion 92 to the wheel side mounting portion 94, whereas a part of the lower edge portion (lower edge portion and bottom surface portion 102 of the wall surface portion 100) 100c of the lower arm 7 bulges downward. With this configuration, the vertical cross section of the bulging portion 104 is also formed to have a U-shaped cross section (see FIG. 12).

[0039] As shown in the drawing, the front and rear wall surface portions 100 are formed with rib portions 100d extending from the damper mounting portion 98 to the stabilizer link mounting portion 96. More specifically, the rib portions 100d are formed along the upper edge portions 100b of the front and rear vertical wall portions 100 from a position above the damper mounting portion 98 to a position above the stabilizer link mounting portion 96. As a modified example, the rib portions (100d) may be formed along the upper edge portions 100b of the front and rear vertical wall portions 100 from a position above the wheel side mounting portion 94 to a position above the stabilizer link mounting portion 96, via a position above the damper mounting portion 98.

[0040] Next, the mounting structure of the damper 14 to the lower arm 7 will be described with reference to Fig. 11 to Fig. 13. Fig. 11 is an enlarged rear view of the rear suspension on the left side of the vehicle of the rear suspension assembly shown in Fig. 3, Fig. 12 is a partially sectional side view seen from the outer side in the longitudinal direction of the lower arm to explain the damper mounting portion and the bulging portion in the lower arm of the rear suspension shown in Fig. 4, and Fig. 13 is a schematic diagram of the lower arm and damper seen from the rear of the vehicle to explain the action of the mounting structure of the damper to the lower arm according to this embodiment, Fig. 13(a) is a comparative example, and Fig. 13(b) shows the configuration of this embodiment. First, as shown in FIG. 11, the damper mounting portion 98 is provided at a position below a straight line (shown by imaginary line A) connecting the pivot portion (connecting portion) 68 on the vehicle body side of the lower arm 7 and the pivot portion (connecting portion) 70 on the wheel side, more specifically, below the straight line (imaginary line A) connecting the above-mentioned vehicle body side mounting portion 92 and wheel side mounting portion 94 of the lower arm 7. Moreover, the distance between the bulging portion 104 and the road surface G is such that a predetermined road clearance as shown in the figure is obtained.

[0041] Next, as shown in Fig. 12, at the position of the damper mounting portion 98 of the lower arm 7 shown in the vertical cross section, the bulge 104 is formed to accommodate the pivot portion 14a of the damper 14. More specifically, as shown in Fig. 12, the pivot portion 14a of the damper 14 is accommodated within the above-mentioned U-shaped cross section at the positions of the damper mounting portion 98 and the bulge 104.

[0042] Next, in this embodiment, as described above, the damper attachment portion 98 is provided at a position below the straight line (imaginary line A in FIG. 11) connecting the pivot portion 70 on the wheel side of the lower arm 7 and the pivot portion 68 on the vehicle body side. As a result, the inclination angle of the axis of the damper 14 (indicated by imaginary line C) when the damper attachment portion 98 is provided at a position below the straight line (imaginary line A) connecting the pivot portions 68, 70 as shown in the example of this embodiment in FIG. 13(b) can be set to a smaller inclination angle in rear view, that is, an inclination angle oriented so that the damper 14 stands more vertically, compared to the inclination angle of the axis of the damper 14 (indicated by imaginary line B) when the damper attachment portion 98 is provided on the straight line connecting the pivot portions 68, 70 as shown in the comparative example in FIG. 13(a).

[0043] The present invention is not limited to the configuration of the above-mentioned embodiment, but includes various other configurations. For example, in this embodiment, the left and right rear suspensions 1 are attached to the vehicle body by the subframe 3, but the present invention is not limited to this, and the rear suspensions 1 may be directly attached to the vehicle body. Furthermore, in order to improve the handling stability, for example, the leading arm 6 and the lower arm 7 may be connected to the wheel support 10 via a ball joint. Furthermore, the bushes are not limited to rubber bushes, and may be made of resin having the required elasticity.

[0044] Next, the effects of this embodiment will be described. The suspension device 1 for an automobile according to this embodiment includes a wheel support 10 that supports a wheel 2 and has an opening 84 formed in the center for passing an axle (not shown), a trailing arm 6 and a lower arm 7 that connect a lower portion (lower vertical wall portion 88) of the wheel support 10 to the vehicle body, an upper arm 4 and a leading arm 5 that connect an upper portion (front vertical wall portion 86) of the wheel support 10 to the vehicle body, a control arm 8 that connects a rear portion (rear vertical wall portion 90) of the wheel support 10 to the vehicle body, and a damper 14 that has an upper end connected to the vehicle body and a lower end connected to the lower arm 7 and is disposed inclined upwardly inwardly in the vehicle width direction when viewed from the rear. The lower arm 7 has an end portion on the vehicle body side that is pivoted via a pivot portion 68. The lower arm 7 is connected to the vehicle body and has its wheel-side end connected to the wheel support 10 via a pivot portion 70, and the damper 14 is connected to the lower arm 7 via a pivot portion 14a. The lower arm 7 has a U-shaped cross-section that opens upward and is formed by front and rear wall portions 100 and a bottom portion 102 extending in its longitudinal direction. The front and rear wall portions 100 of the lower arm 7 have a damper mounting portion 98 that supports the pivot portion 14a of the damper 14 at a position below a straight line (imaginary line A) connecting the pivot portion 70 on the wheel side of the lower arm 7 and the pivot portion 68 on the vehicle body side. A bulge portion 104 that bulges downward to accommodate the pivot portion 14a of the damper 14 is formed on the bottom portion 102 of the lower arm 7 at a position below the damper mounting portion 8. According to this embodiment configured as described above, since the damper mounting portion 98 is set at a position lower than the straight line (imaginary line A) connecting the pivot portion 70 on the wheel side of the lower arm 7 and the pivot portion 68 on the vehicle body side, the inclination angle of the damper 14 (the inclination angle of the axis C) can be made smaller in rear view. In other words, the inclination angle can be set so that the damper 14 stands vertically. Therefore, in the five-link suspension device 1 in which the lower end portion of the damper 14 is supported by the lower arm 7, it is possible to reduce sliding resistance while ensuring road clearance.

[0045] Furthermore, according to this embodiment, the damper mounting portion 98 is set at a position below the straight line (imaginary line A) connecting the pivot portion 70 on the wheel side of the lower arm 7 and the pivot portion 68 on the vehicle body side, and the bulge portion 104 is formed, thereby increasing the area of ​​the wall portion 100. Even if the increased area makes the lower arm 7 (particularly the wall portion 100 in the vicinity of the bulge portion 104) more susceptible to deformation, the rib portions 100d prevent deformation of the front and rear wall portions 100, thereby preventing deformation of the lower arm 7 and suppressing geometric changes in the damper mounting portion 98 and the stabilizer link mounting portion 96. [Explanation of symbols]

[0046] 1. Automobile suspension system / rear suspension 2 Rear wheels 3 Subframe 4 Upper arm (front upper link) 5 Leading arm (rear upper link) 6 Trailing arm (front lower link) 7 Lower arm (rear lower link) 8 Toe control arm (toe control link) 10 Wheel support (support member, hub carrier) 14 Damper 14a Damper pivot part 18 Stabilizer bar 18a Stabilizer link 20 Front cross member 22 Rear cross member 24, 26 Side cross member 88 Lower vertical wall of wheel support (lower arm connecting member) 92 Lower arm mounting part on vehicle body 94 Lower arm wheel side mounting part 96 Lower arm stabilizer link attachment 98 Lower arm damper mounting part 100 Vertical wall of lower arm 100a: Near the damper mounting area 100b Upper edge 100c lower edge 100d rib section 102 Bottom surface of lower arm 104 Lower arm bulge IK Virtual Kingpin Axis

Claims

1. A wheel support that supports a wheel and has an opening formed in the center through which an axle passes; a trailing arm and a lower arm that connect a lower portion of the wheel support to a vehicle body; An upper arm and a leading arm that connect an upper portion of the wheel support to a vehicle body; A control arm that connects a rear portion of the wheel support to a vehicle body; a shock absorber in which a coil spring and a damper are coaxially arranged, the upper end of the damper being connected to a vehicle body and the lower end being connected to the lower arm, the damper being arranged to be inclined upward and inward in a vehicle width direction when viewed from the rear, the lower arm has an end portion on a vehicle body side connected to the vehicle body via a pivot portion, and an end portion on a wheel side connected to the wheel support via a pivot portion, The damper is connected to the lower arm via a pivot portion, The lower arm has a U-shaped cross section that is open upward and is defined by front and rear wall portions and a bottom portion extending in a longitudinal direction thereof, each of the front and rear wall surface portions of the lower arm has a damper mounting portion for pivotally supporting the pivot portion of the damper at a position below a straight line connecting the pivot portion of the lower arm on the wheel side and the pivot portion on the vehicle body side; a bottom surface of the lower arm is formed with a bulge portion below the damper mounting portion, the bulge portion bulging downwardly to accommodate a pivot portion of the damper.

2. the front and rear wall surface portions of the lower arm each have a stabilizer link mounting portion at a position inward in the vehicle width direction from the damper mounting portion, 2. The automobile suspension device according to claim 1, wherein a rib portion is formed on each of the front and rear wall portions of said lower arm, said rib portion extending in the longitudinal direction from at least said damper mounting portion to said stabilizer link mounting portion.

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