Vehicle suspension system

Abstract

To provide a suspension device of a vehicle which generates smooth vehicle attitude change with respect to steering force and an actual steering angle by minimizing a steering roll in the early stage of steering, thereby can effectively make a driver feel successfully operating a vehicle.SOLUTION: There is provided a suspension device 1 of a vehicle, wherein a front suspension 2 has a caster angle τ of +3° to +5° and a caster trail T of +20 to +30 mm, an intersection GK between a ground surface G of a king pin shaft K and the front suspension 2 is a vehicle width direction inside of a tire ground center GC, a cathedral angle α of a lower arm 8 has a geometry of +2.8° to +7.2°, the rear suspension 3 has five links 50, 52, 54, 56 and 58, and a virtual king pin shaft IK has a geometry extending in the vicinity of a tire ground center GC of a rear wheel 46 and vertically extending at -2° to 0° .SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a suspension device for a vehicle, and more particularly to a suspension device for a vehicle equipped with a front suspension for suspending front wheels and a rear suspension for suspending rear wheels. [Background technology]

[0002] Patent Document 1 discloses a strut-type suspension device that suppresses body roll when cornering at low speed by pressing a shock absorber piston against the centrifugal force generated in the vehicle body when steering, thereby increasing the sliding resistance, thereby suppressing roll. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-90129 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is well known that when a vehicle turns, a lateral G force is applied to the vehicle body and the vehicle body rolls, which can be felt by the driver. It is also known that the behavior of the wheel is affected by the positional relationship between the intersection point of the kingpin axis, which is the steering axis of the wheel (tire), or the extension of a virtual kingpin axis, with the ground, and the center of contact with the tire. For example, when designing a front suspension, it is also well known that the geometry, such as the caster angle and caster trail formed by the kingpin axis, is appropriately set while taking into consideration straight-line stability, steering reaction force, etc.

[0005] In response to these issues, the inventors have discovered that at the beginning of a turn when the driver begins to turn the steering wheel, a mechanical roll of the vehicle body (hereinafter referred to as "steering roll") occurs due to the geometry of the suspension, not due to the lateral G of the vehicle body, and this prevents the change in vehicle posture at the beginning of the turn from being smooth, hindering the driver's sense of being able to control the vehicle well.

[0006] That is, for example, (1) When the driver turns the steering wheel, (2) First, "steering roll" occurs, (3) Next, Yaw stands up. (4) Next, roll occurs due to lateral G forces during turning. Thus, the vehicle attitude changes in a complex manner in response to steering, rather than smoothly, which hinders the driver from feeling that he or she is controlling the vehicle well. Here, "turning roll" refers to a roll that is mechanically generated in the vehicle body due to the left and right front wheels rotating around a kingpin axis (virtual kingpin axis) with a caster angle when steering, due to the position of the tire ground contact center, which does not change when steering, and the amount of caster trail from the tire ground contact center, and the like, causing opposite forces to be applied in the vertical direction to the left and right sides of the vehicle body from the left and right front wheels via the left and right front suspension arms, respectively.

[0007] Therefore, the present invention has been made to solve the above-mentioned problems, and has an object to provide a vehicle suspension device that can minimize steering roll at the beginning of a turn, thereby generating a smooth change in vehicle attitude in response to steering force and actual steering angle, thereby giving the driver the feeling that he or she is controlling the vehicle well. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a suspension device for a vehicle including a front suspension that suspends front wheels and a rear suspension that suspends rear wheels, the front suspension having a geometry in which a caster angle formed by a kingpin axis or a virtual kingpin axis is in a range of +3° to +5° in a side view, a caster trail formed by the kingpin axis or the virtual kingpin axis and a tire ground contact center is in a range of +20 to +30 mm in a side view, an intersection of an extension of the kingpin axis or the virtual kingpin axis and the ground is located inward in the vehicle width direction from the tire ground contact center in a front view, the front suspension has a lower arm connecting a vehicle body and a wheel support member, and an anhedral angle of the lower arm is in a range of +2.8° to +7.2° in a front view, and the rear suspension has five links connecting the vehicle body and the wheel support member, and has a geometry in which the virtual kingpin axis extends in the vicinity of the tire ground contact center of the rear wheel and extends vertically at an angle in a range of -2° to 0°.

[0009] According to the present invention configured as described above, the front suspension has a geometry in which the caster angle is in the range of +3° to +5°, the caster trail is in the range of +20 to +30 mm in a side view, the intersection point of the extension of the kingpin axis or the virtual kingpin axis and the ground is located inward in the vehicle width direction from the tire ground contact center in a front view, and the anhedral angle of the lower arm connecting the vehicle body and the wheel support member is in the range of +2.8° to +7.2° in a front view, and the rear suspension has five links connecting the vehicle body and the wheel support member, and the virtual kingpin axis extends in the vicinity of the tire ground contact center of the rear wheels and has a geometry extending vertically at an angle in the range of -2° to 0°, so that the steering roll at the initial stage of turning can be minimized, and as a result, while the roll at the initial stage of turning is suppressed in response to the steering force and the actual steering angle, a roll posture due to centrifugal force can be generated when the vehicle enters a stable turn, thereby achieving a smooth change in vehicle posture. That is, by using the geometry of the front suspension and the geometry of the rear suspension, for example, it is possible to make it possible to make a roll motion occur together with the lateral G acting on the vehicle after the generation of tire lateral force and the accompanying yaw motion among the vehicle behaviors around the three vehicle axles. Here, the imaginary kingpin axis of the rear suspension of the present invention extends in the vicinity of the tire ground contact center of the rear wheel and extends vertically at an angle in the range of -2° to 0°, thereby suppressing the rear roll steer tendency, thereby suppressing the roll of the entire vehicle body, and also suppressing the "steering roll" of the front. As described above, according to the present invention, the "steering roll" in which the vehicle body mechanically rolls at the beginning of a turn is minimized to suppress roll at the beginning of the turn, while a roll posture is generated by centrifugal force when the vehicle enters a stable turn, allowing the driver to feel a smooth turn. As a result, the driver can effectively feel that he or she is maneuvering the vehicle well. In the claims, the statement that specifies a numerical range, such as "a range of A to B," includes A and B as the upper and lower limits.

[0010] In the present invention, the front suspension is preferably a double wishbone suspension including a wheel support member which rotatably supports the front wheels, an upper arm which extends in the vehicle width direction from a connecting portion on the vehicle body side and is connected to the wheel support member via a pivot portion on a higher side of the wheel center of the front wheels, and a lower arm which extends in the vehicle width direction from the connecting portion on the vehicle body side and is connected to the wheel support member via a pivot portion on a lower side of the wheel center of the front wheels, and a kingpin axis is formed by a line connecting the pivot portion of the upper arm and the pivot portion of the lower arm. According to the present invention configured in this manner, in a double wishbone front suspension, it is possible to effectively ensure the suspension support rigidity while minimizing steering roll at the initial stage of turning. As a result, it is possible to suppress roll at the initial stage of turning in relation to the steering force and actual steering angle, while generating a roll posture due to centrifugal force when the vehicle enters a stable turn, thereby realizing a smooth change in vehicle posture.

[0011] Also, in the present invention, the front suspension is preferably a strut-type suspension including a wheel support member that rotatably supports the front wheels, a damper that connects the vehicle body and the wheel support member, and a lower arm that extends in the vehicle width direction from a connecting part on the vehicle body side and is connected to the wheel support member via a pivot part, wherein a kingpin axis is formed by a line connecting an attachment part of the damper to the vehicle body and the pivot part of the lower arm; or a multi-link suspension including a wheel support member that rotatably supports the front wheels and five links that connect the front wheels and the wheel support member, wherein a virtual kingpin axis is formed by the lower links, which are the upper link, leading link, trailing link and lower arm among the five links. According to the present invention configured in this manner, in a strut-type front suspension or a multi-link-type front suspension, steering roll at the beginning of a suspension turn can be minimized. As a result, roll at the beginning of a turn can be suppressed in response to steering force and actual steering angle, while a roll posture is generated by centrifugal force when the vehicle enters a stable turn, thereby achieving a smooth change in vehicle posture.

[0012] In the present invention, preferably, the rear suspension comprises a wheel support member which rotatably supports the rear wheel, an upper link which extends from a connecting portion on the vehicle body side towards the rear of the vehicle and is connected to the wheel support member via a pivot portion above the wheel center of the rear wheel, a leading link which extends from the connecting portion on the vehicle body side towards the front of the vehicle and is connected to the wheel support member via a pivot portion above the wheel center of the rear wheel, a trailing link which extends from the connecting portion on the vehicle body side towards the rear of the vehicle and is connected to the wheel support member via a pivot portion below the wheel center of the rear wheel, and and a toe control link extending in the vehicle width direction from the connecting portion on the vehicle body side and connected to the wheel support member via a pivot portion, wherein a virtual kingpin axis is formed by vertically connecting an intersection of virtual extension lines of the upper link and the leading link with an intersection of virtual extension lines of the trailing link and the lower link, and the pivot portion of the upper link and the pivot portion of the leading link are disposed close to each other at a position forward of the wheel center of the rear wheel. According to the present invention configured in this manner, the pivot portion of the upper link and the pivot portion of the leading link in the wheel support member are positioned close to each other at a position forward of the wheel center of the rear wheel. This suppresses displacement of the imaginary kingpin axis of the rear suspension when the vehicle turns, making it possible to more reliably minimize front steering roll at the beginning of a turn.

[0013] Also, in the present invention, in the rear suspension, the pivot portion of the upper link and the pivot portion of the leading link are preferably arranged so as to overlap in the fore-and-aft direction of the vehicle in a plan view, and also overlap in the up-and-down direction and the width direction of the vehicle in a front view. According to the present invention configured in this manner, the pivot portion of the upper link and the pivot portion of the leading link in the wheel support member can be reliably brought into close proximity to each other and displacement of the imaginary kingpin axis can be suppressed, so that steering roll at the initial stage of turning can be more reliably suppressed to a minimum. Effect of the Invention

[0014] According to the vehicle suspension device of the present invention, by minimizing steering roll at the beginning of a turn, smooth changes in vehicle posture are generated in response to steering force and actual steering angle, thereby allowing the driver to feel as if he or she is maneuvering the vehicle well. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view of a front suspension assembly provided in a vehicle suspension device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a top view of the front suspension assembly shown in FIG. [Diagram 3] FIG. 2 is a front view of the front suspension assembly shown in FIG. [Figure 4] FIG. 2 is a top view of the front suspension on the left side of the vehicle according to the present embodiment. [Diagram 5] FIG. 2 is a side view of the front suspension on the left side of the vehicle according to the present embodiment. [Figure 6] FIG. 2 is a front view of the front suspension on the left side of the vehicle according to the present embodiment. [Figure 7] FIG. 7A is a schematic diagram of the right front wheel viewed from the front to explain the geometry of the front suspension according to this embodiment, and FIG. 7B is a schematic diagram of the right front wheel viewed from the inside in the vehicle width direction to explain the geometry of the front suspension according to this embodiment. [Figure 8] 1 is a perspective view of a rear suspension assembly provided in a vehicle suspension device according to an embodiment of the present invention; [Figure 9]FIG. 9 is a top view of the rear suspension assembly shown in FIG. 8. [Figure 10] FIG. 9 is a rear view of the rear suspension assembly shown in FIG. 8. [Figure 11] FIG. 2 is a top view of the rear suspension on the left side of the vehicle according to the present embodiment. [Figure 12] FIG. 2 is a side view of the rear suspension on the left side of the vehicle according to the present embodiment. [Figure 13] FIG. 2 is a front view of the rear suspension on the left side of the vehicle according to the present embodiment. [Figure 14] FIG. 4 is a top view for explaining the positional relationship of each pivot portion of an upper link and a trailing link in the wheel support of the rear suspension according to the present embodiment. [Figure 15] FIG. 2 is a front view for explaining the positional relationship of each pivot portion of an upper link and a trailing link in a wheel support of the rear suspension according to the present embodiment, with the wheel support not shown. [Figure 16] 1 is a diagram illustrating an example of vehicle motion at the beginning of steering obtained through an experiment on a vehicle equipped with a vehicle suspension device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle suspension device according to an embodiment of the present invention will now be described with reference to the accompanying drawings.

[0017] First, the overall configuration of a front suspension of a vehicle suspension device according to an embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is a perspective view of a front suspension assembly provided in the vehicle suspension device according to an embodiment of the present invention, Figure 2 is a top view of the front suspension assembly shown in Figure 1, and Figure 3 is a front view of the front suspension assembly shown in Figure 1.

[0018] First, as shown in Figures 1 to 3, a vehicle suspension device 1 includes a pair of left and right front suspensions 2, and these front suspensions 2 are attached to a front subframe (suspension subframe) 4 fixed to a vehicle body (not shown).

[0019] The front subframe 4 mainly includes a pair of left and right side cross members 4a, a front cross member 4b extending to connect front ends of the side cross members 4a in the vehicle width direction, and a rear cross member 4c extending in a U-shape in plan view on the vehicle rear side of the front cross members 4b and extending to connect ranges from central portions to rear portions of the side cross members 4a in the vehicle width direction. Note that in Fig. 3, the front cross member 4b is omitted in order to show the front suspension 2. In the figure, reference symbol CL indicates the central plane of the left and right sides of the vehicle body.

[0020] The front suspension 2 of this embodiment is of a double wishbone type and comprises an upper arm 8 attached to the vehicle body above the front wheel 6, a lower arm 10 attached to the side cross member 4a below the upper arm 8, and a wheel support (wheel support member) 12 attached to the upper arm 8 and lower arm 10. The upper arm 8 and the lower arm 10 swing up and down about swing shafts 24 and 30 on the vehicle body side, which will be described later, respectively, so that the wheel support 12 and the front wheel 6 stroke up and down along a predetermined trajectory. The wheel support 12 is a hub carrier that supports a hub 14 to which a wheel (not shown) of the front wheel 6 is attached.

[0021] The front suspension 2 is also provided with a shock absorber 20 equipped with a coil spring 16 and a damper 18 to provide a predetermined biasing force and damping force while at the same time allowing for such stroke of the front wheel 6. The shock absorber 20 has a vertically long cylindrical shape in which the coil spring 16 and the damper 18 are arranged approximately coaxially, with its upper end attached to the vehicle body and its lower end (the lower end of the damper 18) rotatably attached to the lower arm 10. Although not shown, the front suspension 2 includes a steering gear unit, and a tie rod extending outward in the vehicle width direction from the steering gear unit and attached to the wheel support 12 to steer the front wheels 6. In addition, an anti-roll bar (not shown) extending in the vehicle width direction to connect the left and right lower arms 10 is rotatably attached to the lower arms 10 and the front cross member 4b.

[0022] Next, the configuration of the front suspension 2 will be specifically described with reference to Figures 4 to 6. Figure 4 is a top view of the front suspension on the left side of the vehicle according to this embodiment, Figure 5 is a side view of the front suspension on the left side of the vehicle according to this embodiment, and Figure 6 is a front view of the front suspension on the left side of the vehicle according to this embodiment. Here, the front suspension 2 on the right front wheel side and the left front wheel side has the same basic structure, so here, the front suspension on the left front wheel side will be mainly described.

[0023] First, as shown in Figures 4 to 6, the upper arm 8 is an A-shaped arm in which a front arm portion 8a extending diagonally rearward outward in the vehicle width direction and a rear arm portion 8b extending diagonally forward outward in the vehicle width direction are integrally formed. The upper arm 8 has two inner ends in the vehicle width direction connected to the vehicle body via cylindrical elastic bushes 22 each having a central axis in the vehicle front-rear direction. These elastic bushes 22 form a swing shaft 24 of the upper arm 8 extending in the vehicle front-rear direction. The axis of the elastic bush 22 and the swing shaft 24 are inclined several degrees rearward of the vehicle in a side view.

[0024] The lower arm 10 is an A-shaped arm having a front arm portion 10a extending substantially in the vehicle width direction and a rear arm portion 10b extending diagonally forward outward in the vehicle width direction. The lower arm 10 has an inner end of the front arm portion 10a connected to the side cross member 4a via a cylindrical elastic bush 26 having a central axis in the vehicle front-rear direction, and an inner end of the rear arm portion 10b in the vehicle width direction and rearward connected to the side cross member 4a via a cylindrical elastic bush 28 having a central axis in the vehicle front-rear direction. These elastic bushes 26, 28 form a swing shaft 30 of the lower arm 10 extending in the vehicle front-rear direction. The rear arm portion 10b has a so-called Γ shape, and its outer end in the vehicle width direction is fastened at two points to the front arm portion 10a at a central portion 34 inward in the vehicle width direction from a connecting portion 32 at the lower end of the damper 18 (see Figs. 1 and 6).

[0025] The outer ends of the upper arm 8 and the lower arm 10 in the vehicle width direction are connected to the wheel support 12 via pivot portions 36, 38, respectively. Specifically, as shown in Figures 5 and 6, the wheel support 12 has an extension portion 12a for connecting the upper arm that extends upward and an extension portion 12b for connecting the lower arm that extends downward, and each arm 8, 10 is connected to the upper and lower ends of these extension portions 12a, 12b via ball joints (pillow ball joints) 40, 42 that form the pivot portions 36, 38, respectively. As shown in Figs. 4 and 5, the wheel support 12 includes an extension (knuckle arm) 12c for connecting a tie rod, which extends toward the front of the vehicle body, and a tie rod (not shown) is attached to the tip of this extension 12c.

[0026] Next, as shown in Figures 5 and 6, in the front suspension 2, a kingpin axis K, which is the steering axis of the front wheel 6, is formed on a straight line (shown by a dashed line in the figures) connecting the center of the pivot portion 36 on the front wheel 6 side of the above-mentioned upper arm 8 and the center of the pivot portion 38 on the front wheel 6 side of the lower arm 10. Furthermore, the symbol WC shown in Figures 4 to 6 is the wheel center of the front wheel 6, and in Figure 4, the vehicle widthwise central axis of the front wheel 6 that passes through the wheel center WC and the line indicating the vertical central plane of the front wheel 6 are each shown by dashed lines, and in Figures 5 and 6, the vertical axis and horizontal axis that pass through the wheel center WC and divide the front wheel 6 into front-to-rear and top-to-bottom are each shown by dashed lines.

[0027] Next, the main geometry of the front suspension 2 according to the embodiment of the present invention will be described with reference to Figures 5 to 7. Figure 7A is a schematic diagram of the right front wheel viewed from the front for explaining the geometry of the front suspension according to this embodiment, and Figure 7B is a schematic diagram of the right front wheel viewed from the inside in the vehicle width direction for explaining the geometry of the front suspension according to this embodiment. 7A and 7B are front wheels 6, and as shown in Fig. 7A, the distance between the intersection GK of the kingpin axis K and the ground G and the tire ground contact center (tire ground contact pressure center) GC in a front view is the so-called kingpin offset KO. In this embodiment, as shown in Fig. 6, the geometry of the arms 8, 10 and the damper 18, as well as the camber angle of the front wheels 6, are set so that the value of this kingpin offset KO is positive (+) in the range of 13 mm to 22 mm, that is, so that the intersection GK of the extension of the kingpin axis K and the ground G is located inside the tire ground contact center GC in the vehicle width direction. In the description of this embodiment, the description of a numerical range "in the range of A to B" means that A and B are included as the upper and lower limit values. For example, the above-mentioned "in the range of 13 mm to 22 mm" means 13 mm or more and 22 mm or less. The same applies below.

[0028] Next, as shown in Fig. 7B, the angle that the kingpin axis K makes with a vertical line in a side view is the caster angle τ, and in this embodiment shown in Fig. 5, the geometry of the arms 8, 10 and the damper 18 are set so that the caster angle τ is approximately 4°. In this embodiment, the value of the caster angle τ of the front wheels 6 may be in the range of 3° to 5°. The caster angle τ is positive (+) when the upper part of the kingpin axis K is tilted backward in a side view.

[0029] As shown in Fig. 7B, in a side view, the distance between an intersection GK between an extension of the kingpin axis K and the ground G and the tire ground contact center GC is the caster trail T, and in this embodiment shown in Fig. 5, the geometry of the arms 8, 10 and the damper 18 is set so that the value of the caster trail T is approximately 21 mm. In this embodiment, the value of the caster trail T may be in the range of +20 mm to +30 mm. The caster trail T is positive (+) when the intersection GK is forward of the tire ground contact center GC in a side view.

[0030] As shown in FIG. 7B, the caster trail T and the caster angle τ have a relationship roughly expressed by trigonometric functions using the so-called hub trail (caster trail at the wheel center) Th and the tire radius r, as expressed by the following equation (1). T=r×sin(τ)+Th...Equation (1) Where: T is caster trail, r is the tire radius τ is the caster angle Th is Hub Trail, It is. For example, when an 18-inch tire is mounted on the front wheel 6 and the hub trail is 5 mm, the value of the caster trail T is calculated from the formula (1) in this embodiment as follows: 20.9mm=25.4mm(18 inches)÷2×sin(τ)(4°)+5mm This is calculated to be approximately 21 mm. In this embodiment, the tire size of the front wheel 6 is assumed to be 16 inches to 19 inches, and the value of the caster trail T is set in the range of +20 mm to +30 mm according to the values ​​of the caster angle τ, tire diameter (radius r), hub trail Th, etc.

[0031] 6, in this embodiment, the lower arm 10 is disposed so that the anhedral angle α is about 5°. In this embodiment, the anhedral angle α of the lower arm 10 is set in the range of +2.8° to +7.2° according to variations in the wheelbase, tire width, vehicle weight (mainly assuming engines of different specifications) of the vehicle on which the vehicle suspension device 1 of this embodiment is mounted. In this embodiment, the anhedral angle α of the lower arm 10 is set as an upward arm angle from the wheel side toward the vehicle body, which is an angle formed by a line L connecting the center of the pivot portion 38 on the front wheel 6 side and the central axis of the elastic bush 26 on the vehicle body side in the front arm portion 10a of the lower arm 10 in a front view with a horizontal line HL. In this embodiment, the elastic bush 26 and the elastic bush 28 on the vehicle body side of the lower arm 10 are set at approximately the same height in the vehicle front-rear direction, so the anhedral angle α may be set as the angle of a line connecting the center of the pivot portion 38 on the front wheel 6 side and the swing shaft 30 of the lower arm 10. The jacking-up force caused by such anhedral angle α of the lower arm 10 becomes a resistance force that suppresses the steering roll itself.

[0032] Here, as a modified example of the front suspension 2 of this embodiment, although not shown in the figures, instead of the double wishbone type described above, a strut-type front suspension may be used which includes a wheel support member that rotatably supports the front wheels, a damper that connects the vehicle body and the wheel support member, and a lower arm that extends in the vehicle width direction from a connecting part on the vehicle body side and is connected to the wheel support member via a pivot part, with the kingpin axis K being formed by a line connecting the mounting part of the damper to the vehicle body and the pivot part of the lower arm. In this modified example, as in the above-described embodiment, as shown in FIG. 7, it is sufficient that the geometry is such that the caster angle τ formed by the kingpin axis K is in the range of +3° to +5°, the caster trail T formed by the kingpin axis K and the tire ground contact center GC is in the range of +20 to +30 mm, the intersection GK between the extension of the kingpin axis K and the ground G is located inside in the vehicle width direction from the tire ground contact center GC in a front view, and the anhedral angle α of the lower arm connecting the vehicle body and the wheel support member is in the range of +2.8° to +7.2° in a front view.

[0033] As a further modified example of the front suspension 2 of this embodiment, although not shown in the figures, instead of the double wishbone type described above, a multi-link front suspension may be used which has a wheel support member that rotatably supports the front wheels, and five links that connect the wheels and the wheel support member, in which a virtual kingpin axis is formed by the arrangement of each of the five links, namely, an upper link, a leading link, a trailing link, and a lower link. In this modified example, as in the above-described embodiment, as shown in FIG. 7, it is sufficient that the geometry is such that the caster angle τ formed by the imaginary kingpin axis IK is in the range of +3° to +5°, the caster trail T formed by the imaginary kingpin axis IK and the tire ground contact center GC is in the range of +20 to +30 mm, the intersection GK between the extension of the imaginary kingpin axis IK and the ground G is located inside in the vehicle width direction relative to the tire ground contact center GC, and the anhedral angle α of the lower link connecting the vehicle body and the wheel support member is in the range of +2.8° to +7.2° in a front view.

[0034] Next, the overall configuration of the rear suspension 3 of the vehicle suspension device according to the embodiment of the present invention will be described with reference to Figures 8 to 10. Figure 8 is a perspective view of the rear suspension assembly provided in the vehicle suspension device according to the embodiment of the present invention, Figure 9 is a top view of the rear suspension assembly shown in Figure 8, and Figure 10 is a rear view of the rear suspension assembly shown in Figure 8. First, as shown in Figures 8 to 10, a vehicle suspension device 1 includes a pair of left and right rear suspensions 3, and these rear suspensions 3 are attached to a rear subframe (suspension subframe) 44 fixed to a vehicle body (not shown).

[0035] The rear subframe 44 mainly includes a pair of left and right side cross members 44a, a front cross member 44b extending to connect front ends of the side cross members 44a in the vehicle width direction, and a rear cross member 44c extending to connect rear ends of the side cross members 40a in the vehicle width direction. In the drawings, the symbol CL indicates the central plane of the left and right sides of the vehicle body.

[0036] The rear suspension 3 of this embodiment is of a multi-link type in which a wheel support (wheel supporting member) 48 of a rear wheel 46 is connected to the vehicle body by five independent I-links 50, 52, 54, 56, and 58 in a manner allowing for movement. Specifically, rear suspension 3 includes a front upper link (upper arm) 50 and a rear leading link (leading arm) 52 which form a virtual upper arm, a front trailing link (trailing arm) 54 and a rear lower link (lower arm) 56 which form a virtual lower arm, and a toe control link (toe control arm) 58 which regulates the rotational displacement of rear wheel 46 about a virtual kingpin axis IK (see Figures 12 and 13) which will be described later.

[0037] The upper link 50, leading link 52, trailing link 54 and lower link 56 each swing up and down around a vehicle body-side connecting portion (elastic bushings 70, 74, 82, 86) described below, thereby allowing the wheel support 48 and rear wheel 46 to stroke up and down along a predetermined trajectory. The wheel support 48 is a hub carrier that supports a hub 60 to which a wheel (not shown) of the rear wheel 46 is attached.

[0038] A shock absorber 66 is provided that includes a coil spring 62 and a damper 64 to apply a predetermined biasing force and damping force while allowing such a stroke of the rear wheels 46. The shock absorber 66 has a vertically long cylindrical shape in which the coil spring 62 and the damper 64 are arranged approximately coaxially, with an upper end attached to the vehicle body and a lower end (the lower end of the damper 64) rotatably connected to the lower link 56. An anti-roll bar 68 is rotatably attached to the rear suspension 3, extending so as to connect the left and right lower links 56.

[0039] Next, the configuration of the rear suspension 3 will be specifically described with reference to Figures 11 to 13. Figure 11 is a top view of the rear suspension on the left side of the vehicle according to this embodiment, Figure 12 is a side view of the rear suspension on the left side of the vehicle according to this embodiment, and Figure 13 is a front view of the rear suspension on the left side of the vehicle according to this embodiment. Here, the rear suspension 3 on the right rear wheel side and the left rear wheel side has the same basic structure, so here, the left rear wheel side rear suspension will be mainly described.

[0040] 11 to 14, the upper link 50 has an inner end in the vehicle width direction connected to the side cross member 44a via an elastic bush 70 extending in the vehicle front-rear direction (disposed at an incline of several degrees in a plan view). The upper link 50 extends at a rearward incline so as to be gradually positioned rearward from the connecting portion on the vehicle body side toward the outer side in the vehicle width direction when viewed from above the vehicle. The outer end in the vehicle width direction is connected to the wheel support 48 via a pivot portion 72.

[0041] Next, the leading link 52 has an inner end in the vehicle width direction connected to the side cross member 44a via an elastic bush 74 extending in the vehicle front-rear direction (positioned at an incline of several degrees in a plan view). The leading link 52 extends at an inclination so as to be gradually positioned forward from the connecting portion on the vehicle body side toward the outer side in the vehicle width direction when viewed from above the vehicle, and has an outer end in the vehicle width direction connected to the wheel support 48 via a pivot portion 76.

[0042] In this way, the two upper links 50, 52 are disposed so as to approach each other toward the outside of the vehicle body when viewed from above the vehicle, and form an imaginary upper arm. In this embodiment, ball joints (pillow ball joints) 78, 80, which will be described later, are employed at the pivot portions 72, 76 of the wheel support 48 of the links 50, 52, respectively.

[0043] Next, the trailing link 54 has an inner end in the vehicle width direction connected to the side cross member 44a via an elastic bush 82 extending in the vehicle fore-aft direction (inclined at several degrees in a plan view). The trailing link 54 extends at a rearward incline so as to be gradually positioned rearward from the connecting portion on the vehicle body side toward the outer side in the vehicle width direction when viewed from above the vehicle, and has an outer end in the vehicle width direction connected to the wheel support 48 via an elastic bush 84 extending in the vehicle fore-aft direction (inclined at several degrees in a plan view).

[0044] Next, the lower link 56 has an inner end in the vehicle width direction connected to the side cross member 4a via an elastic bush 86 extending in the vehicle fore-aft direction (inclined at several degrees in a plan view). The lower link 56 extends at a forward incline so as to be gradually positioned forward from the connecting portion on the vehicle body side toward the outer side in the vehicle width direction when viewed from above the vehicle, and the outer end in the vehicle width direction is connected to the wheel support 48 via an elastic bush 88 extending in the vehicle fore-aft direction (inclined at several degrees in a plan view).

[0045] In this way, the two lower links 54, 56 are disposed so as to approach each other outward in the vehicle width direction when viewed from above the vehicle, and form an imaginary lower arm.

[0046] Next, the toe control link 58 has its end on the vehicle body side connected to a journal portion 90 on the rear surface of the rear cross member 44c so as to be able to swing up and down. When viewed from above the vehicle, the toe control link 58 extends at a forward incline so as to be gradually positioned forward from the connecting portion on the vehicle body side toward the outside in the vehicle width direction. The end on the outside in the vehicle width direction is connected to the wheel support 48 via an elastic bush 92.

[0047] Next, the main geometry of the front suspension 2 according to the embodiment of the present invention will be described with reference to FIGS. First, as shown in Figures 11 to 13, the rear suspension 3 has an imaginary kingpin axis IK that vertically connects an intersection P1 between an imaginary extension line of the upper link 50 and an imaginary extension line of the leading link 52, and an intersection P2 between an imaginary extension line of the trailing link 54 and an imaginary extension line of the lower link 56. This imaginary kingpin axis IK is an instantaneous rotation center of the rear wheel 46 in the steering direction (toe direction). Here, the symbol WC shown in Figures 11 to 13 is the wheel center of the rear wheel 46, and in Figure 11, the vehicle width direction axis of the rear wheel 46 that passes through the wheel center WC and a line indicating the vertical center plane of the rear wheel 46 are respectively indicated by dashed lines, and in Figures 12 and 13, the vertical axis and horizontal axis that pass through the wheel center WC and divide the rear wheel 46 into front-rear and top-bottom halves are respectively indicated by dashed lines.

[0048] Next, as shown in FIG. 12, in the rear suspension 3 of this embodiment, the geometry of each link 50, 52, 54, 56 is set so that the imaginary kingpin axis IK extends substantially vertically near the tire ground contact center GC of the rear wheel 46 and on the vehicle front side in side view. In this embodiment, the imaginary kingpin axis IK extends so that the intersection GK of the imaginary kingpin axis IK with the ground G is located within a distance range of -120 mm to +120 mm from the tire ground contact center GC. The inclination angle of the imaginary kingpin axis IK is an angle in the range of -2° to 0°. Note that the inclination angle is positive (+) when the upper part of the imaginary kingpin axis IK is inclined backward in side view, and in this embodiment, it is sufficient that the inclination angle is from a position where the imaginary kingpin axis IK extends vertically at an angle of 0° to a position where the upper part of the imaginary kingpin axis IK is inclined forward by -2°.

[0049] 12, in this embodiment, the coil spring 62 and the damper 64 are coaxially arranged to concentrate the load received by the shock absorber 66. Furthermore, in this embodiment, the wheel center WC, which is the load input point from the rear wheel 46, and the pivot portion (elastic bush) 88, which is the load support point of the lower link (lower arm) 56 that receives the lateral force mainly from the rear wheel 46, are aligned on a vertical line, that is, the offset in the vehicle fore-and-aft direction between the load input point from the rear wheel 46 and the load support point of the lower link 56 that receives the load is set to 0 (zero), thereby making the internal force 0 (zero). This suppresses changes in the alignment of the rear suspension 3 due to the external force input from the rear wheel 46.

[0050] Next, the configurations of the pivot portions 72, 76 of the upper link 50 and the leading link 52 according to an embodiment of the present invention will be described with reference to Figures 11 to 15. Figure 14 is a top view for explaining the positional relationship of the pivot portions of the upper link and the trailing link in the wheel support of the rear suspension according to this embodiment, and Figure 15 is a front view for explaining the positional relationship of the pivot portions of the upper link and the trailing link in the wheel support of the rear suspension according to this embodiment, with the wheel support omitted.

[0051] First, as shown in Figures 11 to 14, at each end of the upper link 50 and the leading link 52 on the outer side in the vehicle width direction, there is provided a pillow ball joint 78, 80 having a ball portion (not shown) arranged to be rotatable around three axes (X, Y, Z) within that end, a pillow ball housing 94, 96 that holds this ball portion, and a shaft portion (not shown) extending from the ball portion toward the front of the vehicle.

[0052] In this embodiment, the pillow ball housings 94, 96 are portions with a circular (annular) cross section that surround each ball portion and have a predetermined thickness (15 mm in this embodiment), and in this embodiment, are formed at the outer ends in the vehicle width direction of each of the upper link 50 and the leading link 52. In addition, the tip end of a shaft portion (not shown) extending from the ball portion is fastened to the front wall portion 48a formed forward of the wheel center WC of the wheel support 12. In this embodiment, the pivot portions 72, 76 are formed by the pillow ball joints 78, 80 having such a configuration.

[0053] Next, in this embodiment, as shown in Figures 11 to 15, the pivot portion 72 of the upper link 50 and the pivot portion 76 of the leading link 52 are disposed close to each other at a position forward of the wheel center WC of the rear wheel 46. 14, for example, each of the pivot portions 72, 76 (pillow ball joints 78, 80) has a predetermined length (indicated by symbols L1, L2) in the vehicle fore-and-aft direction. In this embodiment, the pivot portions 72, 76 overlap in the vehicle fore-and-aft direction in top and side views, and this overlapping range is indicated by symbol L3 in the drawing.

[0054] 15, for example, the formation range A1 of the pivot portion 72 of the upper link 50 as viewed from the front of the vehicle is shown by a virtual line, and the formation range A2 of the pivot portion 76 of the leading link 52 is shown by a virtual line. In this embodiment, the pivot portion 72 (pillow ball joint 78) of the upper link 50 and the pivot portion 76 (pillow ball joint 80) of the leading link 52 are arranged to overlap in the vehicle up-down direction and the vehicle width direction in a front view. More specifically, in FIG. 15, the formation range A1 of the pivot portion 72 and the formation range A2 of the pivot portion 76 overlap in the vehicle up-down direction and the vehicle width direction, as shown by an overlapping range A3. In this embodiment, as shown in FIG. 13, pivot portion 72 is disposed adjacent to pivot portion 76 at an angle of approximately 45 degrees downward in the vertical direction of the vehicle and inward in the width direction of the vehicle when viewed from the front and rear.

[0055] Next, the action of vehicle behavior obtained by a running experiment on a test vehicle equipped with the vehicle suspension device 1 according to an embodiment of the present invention will be described with reference to Fig. 16. Fig. 16 is a diagram for explaining an example of vehicle motion at the beginning of steering obtained by an experiment on a vehicle equipped with the vehicle suspension device according to an embodiment of the present invention. The vertical axis of Fig. 16 indicates values ​​such as the steering angle, and the horizontal axis indicates the time from when the driver starts steering while driving. In the time chart shown in Fig. 16, after the steering start (0 seconds), the steering angle (actual steering angle) rises first, and then the yaw motion of the vehicle occurs early. After that, at a certain timing, almost simultaneously, the lateral G rises and the roll angle of the vehicle body rises. Although not shown on the time scale in Fig. 16, it has been experimentally found that the roll angle that rises at the certain timing then increases linearly. And, as shown in Fig. 16, the occurrence of roll caused by "steering roll" is suppressed. In other words, the roll angle is suppressed to a minimum value that does not affect the vehicle behavior or the driver's driving sensation from the time steering starts to the time the roll angle of the vehicle body rises.

[0056] Here, conventionally, when a driver steers the steering wheel as described above, first a "steering roll" occurs, then a yaw rises, and then a roll occurs due to the lateral G force during turning. In this manner, the vehicle attitude changes in a complex manner in response to the steering, and a smooth change in vehicle attitude cannot be obtained. However, in a vehicle equipped with the vehicle suspension device 1 having the geometry described above according to this embodiment, as shown in an example in Fig. 16, it has been confirmed that the steering roll at the beginning of turning is suppressed to a minimum, and thus a smooth change in vehicle attitude occurs in response to the steering force and actual steering angle.

[0057] Next, a design method for the suspension device of the vehicle of this embodiment may include the steps of setting the caster angle τ in the range of +3° to +5°, setting the caster trail T in the range of +20 to +30 mm, setting an intersection GK between an extension line of the kingpin axis K or the virtual kingpin axis IK and the ground G on the vehicle width direction inner side of the tire ground contact center GC, setting the anhedral angle α of the lower arm connecting the vehicle body and the wheel support 12 in the range of +2.8° to +7.2°, determining the arrangement of each arm, each link, each pivot portion and / or damper of the front suspension so as to obtain the numerical value, arrangement, and kingpin axis K or virtual kingpin axis IK set in each of these steps, setting the virtual kingpin axis IK to extend in the vicinity of the tire ground contact center GC of the rear wheel, setting the virtual kingpin axis IK to extend vertically at an angle in the range of -2° to 0°, and determining the arrangement of five links and each pivot portion of the rear suspension so as to obtain the virtual kingpin axis IK set in each of these steps. Moreover, the above-mentioned formula "T=r×sin(τ)+Th··· formula (1)" may be used in such a design method.

[0058] Although not shown, the automobile (vehicle) of this embodiment is a rear-wheel drive vehicle in which the front wheels 6 are steered by a steering device, an engine is mounted in an engine room at the front of the vehicle body, a differential is disposed at the rear of the vehicle body, and rear wheels 46 are driven by axles. This embodiment may also be applied to a front-wheel drive vehicle.

[0059] The present invention is not limited to the configurations of the above-described embodiments, but includes various other configurations. For example, in order to improve handling stability, the leading link 52, the lower link 56, etc. may be connected to the wheel support 48 via a ball joint. The elastic bushing is not limited to a rubber bushing, and may be made of a resin having the required elasticity.

[0060] Next, the effects of the vehicle suspension device according to this embodiment and its modified example will be described. The vehicle suspension device 1 according to the present embodiment and the modified example includes a front suspension 2 that suspends a front wheel 6 and a rear suspension 3 that suspends a rear wheel 46. The front suspension 2 has a caster angle τ formed by a kingpin axis K or a virtual kingpin axis IK in a range of +3° to +5° in a side view, a caster trail T formed by the kingpin axis K or the virtual kingpin axis IK and the tire ground contact center GC in a range of +20 to +30 mm in a side view, and The intersection GK of the extension of the kingpin axis IK and the ground G is located widthwise inward of the tire ground contact center GC in a front view, and the lower arm 10 connecting the vehicle body and the wheel support 12 has a geometry in which the anhedral angle α is in the range of +2.8° to +7.2° in a front view.The rear suspension 3 has five links 50, 52, 54, 56, 58 connecting the vehicle body and the wheel support 48, and has a geometry in which the virtual kingpin axis IK extends near the tire ground contact center GC of the rear wheel 46 and extends vertically at an angle in the range of -2° to 0°.

[0061] According to the present embodiment and the modified example configured as described above, the geometry of the front suspension 2 and the rear suspension 3 can minimize steering roll at the beginning of a turn, thereby suppressing roll at the beginning of a turn relative to the steering force and the actual steering angle, and generating a roll posture due to centrifugal force when the vehicle enters a stable turn, thereby realizing a smooth change in vehicle posture. That is, for example, among the vehicle behaviors around the three vehicle axles, after the generation of tire lateral force and the associated pitch, a roll motion can be generated together with the lateral G applied to the vehicle. Here, since the vehicle body is basically a rigid body, if the rear imaginary kingpin axis IK does not extend nearly vertically and near the tire ground contact center GC as in this embodiment, the rear suspension 3 will have a tendency to roll steer as if it is dragged by the roll of the entire vehicle body. In contrast, the rear suspension 3 of this embodiment has a geometry in which the imaginary kingpin axis IK extends near the tire ground contact center GC of the rear wheel 46 and extends vertically at an angle in the range of -2° to 0°, suppressing this roll steer tendency, thereby suppressing the roll of the entire vehicle body, and thereby suppressing the "steering roll" of the front. As described above, according to this embodiment, the "steering roll" that occurs when the steering wheel is turned at the beginning of a turn is minimized to suppress roll at the beginning of the turn, and when the vehicle enters a stable turn, a roll posture is generated by centrifugal force, allowing the driver to feel a smooth turn. As a result, the driver can effectively feel that he or she is maneuvering the vehicle well. For the driver, it is ideal that the "actual steering angle" occurs when the steering force is generated (when the driver feels a "feeling of resistance"), so that the vehicle behavior and the driver's steering sensation match. This can be achieved by appropriately adjusting the "dead zone" of the steering, and the above-mentioned effects of this embodiment can be obtained more effectively.

[0062] Furthermore, according to this embodiment, the front suspension 2 is a double wishbone suspension comprising: a wheel support 12 that rotatably supports the front wheel 6; an upper arm 8 that extends in the vehicle width direction from a connecting portion on the vehicle body side and is connected to the wheel support 12 via a pivot portion 36 on the upper side of the wheel center WC of the front wheel 6; and a lower arm 10 that extends in the vehicle width direction from a connecting portion on the vehicle body side and is connected to the wheel support 12 via a pivot portion 38 on the lower side of the wheel center WC of the front wheel 6, and a kingpin axis K is formed by a line connecting the pivot portion 36 of the upper arm 8 and the pivot portion 38 of the lower arm 10. According to the present invention configured in this manner, in the double wishbone front suspension 2, the steering roll at the beginning of a turn can be minimized while effectively ensuring the suspension support rigidity. As a result, while suppressing the roll at the beginning of a turn in relation to the steering force and actual steering angle, a roll posture is generated by centrifugal force when the vehicle enters a stable turn, thereby realizing a smooth change in vehicle posture.

[0063] Furthermore, according to a modified example of this embodiment, the front suspension is a strut-type suspension including a wheel support 12 that rotatably supports the front wheels, a damper that connects the vehicle body and the wheel support member, and a lower arm that extends in the vehicle width direction from a connecting portion on the vehicle body side and is connected to the wheel support member via a pivot portion, with a kingpin axis K being formed by a line connecting an attachment portion of the damper to the vehicle body and the pivot portion of the lower arm, or a multi-link suspension including a wheel support member that rotatably supports the front wheels and five links that connect the front wheels and the wheel support member, with a virtual kingpin axis IK being formed by an upper link, a leading link, a trailing link and a lower link (lower arm) among the five links. According to the modified example of the present embodiment configured in this manner, in a strut-type front suspension or a multi-link front suspension, steering roll at the beginning of a suspension turn can be minimized. As a result, while suppressing roll at the beginning of a turn in relation to the steering force and actual steering angle, a roll posture is generated by centrifugal force when the vehicle enters a stable turn, thereby achieving a smooth change in vehicle posture.

[0064] Further, according to this embodiment and its modified examples, the rear suspension 3 comprises a wheel support 48 that rotatably supports the rear wheel 46, an upper link 50 that extends from the connecting portion on the vehicle body side toward the rear of the vehicle and is connected to the wheel support 48 via a pivot portion 72 above the wheel center WC of the rear wheel 46, a leading link 52 that extends from the connecting portion on the vehicle body side toward the front of the vehicle and is connected to the wheel support 48 via a pivot portion 76 above the wheel center WC of the rear wheel 46, a trailing link 54 that extends from the connecting portion on the vehicle body side toward the rear of the vehicle and is connected to the wheel support 48 via a pivot portion (elastic bush 84) below the wheel center WC of the rear wheel 46, and a trailing link 54 that extends from the connecting portion on the vehicle body side toward the front of the vehicle and is connected to the wheel support 48 via a pivot portion (elastic bush 84) below the wheel center WC of the rear wheel 46. The vehicle is provided with lower links (lower arms) 56 connected to wheel supports 48 on both lower sides via pivot portions (elastic bushings 88), and a toe control link 58 extending in the vehicle width direction from the connecting portion on the vehicle body side and connected to wheel support 48 via a pivot portion (elastic bushing 92). A virtual kingpin axis IK is formed by vertically connecting an intersection point P1 on each of the virtual extension lines of the upper link 50 and the leading link 52 with an intersection point P2 on each of the virtual extension lines of the trailing link 54 and the lower link 56, and the pivot portion 72 (pillow ball joint 78) of the upper link 50 and the pivot portion 76 (pillow ball joint 80) of the leading link 52 are positioned so that they are close to each other at a position forward of the wheel center WC of the rear wheel 46. According to this embodiment and the modified example configured as described above, the displacement of the imaginary kingpin axis IK of the rear suspension 3 is suppressed when the vehicle is turning, and the steering roll at the initial stage of turning can be more reliably suppressed to a minimum.

[0065] Furthermore, according to this embodiment and its modified examples, in the rear suspension 3, the pivot portion 72 (ball joint 78) of the upper link 50 and the pivot portion 76 (pillow ball joint 80) of the leading link 52 are arranged so as to overlap in the fore-and-aft direction of the vehicle in a plan view, and also overlap in the up-and-down direction and width direction of the vehicle in a front view, so that the pivot portion 72 (pillow ball joint 78) of the upper link 50 and the pivot portion 76 (ball joint 80) of the leading link 52 can be brought closer together more reliably. [Explanation of symbols]

[0066] 1. Vehicle suspension system 2. Front suspension 3. Rear suspension 4 Front subframe (suspension subframe) 6 Front Wheel 8 Upper Arm 10 Lower Arm 12 Wheel support (wheel support member, hub carrier) 22, 26 Elastic bush 28 Pivot part 24, 30 Swing axis 36, 38 Pivot part 40, 42 Ball joint 44 Rear subframe (suspension subframe) 46 Rear wheel 48 Wheel support (wheel support member, hub carrier) 50 Upper link (upper arm) 52 Leading link (leading arm) 54 Trailing link (trailing arm) 56 Lower link (lower arm) 58 Toe control link (toe control arm) 70, 74 Elastic bushing 72, 76 Pivot part 78, 80 Ball joint (Pillow ball joint) 82, 84, 86, 88, 92 Elastic bushings K Kingpin shaft IK Virtual Kingpin Axis GK Intersection of kingpin axis K and ground G GC Tire contact center (tire contact pressure center) KO Kingpin Offset τ Castor angle T Caster Trail α anhedral angle P1, P2 Intersection of virtual extension lines of each rear link A3 Pivot part (pillow ball joint) forming area overlapping area L3 Pivot part (pillow ball joint) overlap length in the vehicle front-rear direction

Claims

1. A suspension device for a vehicle having a front suspension for suspending front wheels and a rear suspension for suspending rear wheels, The front suspension is The caster angle formed by the kingpin axis or the virtual kingpin axis is in the range of +3° to +5° in a side view, a caster trail formed by the kingpin axis or the virtual kingpin axis and the tire ground contact center is in the range of +20 to +30 mm in a side view, an intersection point between an extension of the kingpin axis or the virtual kingpin axis and the ground is located inside in a vehicle width direction from a tire ground contact center in a front view, A lower arm is provided to connect a vehicle body and a wheel support member, and the lower arm has a geometry in which an anhedral angle is in a range of +2.8° to +7.2° when viewed from the front, The rear suspension is A suspension device for a vehicle, comprising five links connecting a vehicle body and a wheel support member, and characterized in that a virtual kingpin axis extends in the vicinity of a tire ground contact center of a rear wheel and has a geometry that extends vertically at an angle in the range of -2° to 0°.

2. The front suspension is The wheel support member supports the front wheels so as to be able to rotate freely; an upper arm extending in a vehicle width direction from a connecting portion on a vehicle body side and connected to the wheel support member via a pivot portion on a vehicle upper side relative to a wheel center of the front wheel; the lower arm extending in a vehicle width direction from a connecting portion on a vehicle body side and connected to the wheel support member via a pivot portion on a vehicle lower side than a wheel center of a front wheel, 2. The vehicle suspension device according to claim 1, wherein the suspension is a double wishbone type suspension, in which the kingpin axis is formed by a line connecting the pivot portion of the upper arm and the pivot portion of the lower arm.

3. 2. The vehicle suspension device according to claim 1, wherein the front suspension is a strut-type suspension comprising: the wheel support member supporting a front wheel rotatably; a damper connecting a vehicle body and the wheel support member; and the lower arm extending in a vehicle width direction from a connecting portion on the vehicle body side and connected to the wheel support member via a pivot portion, wherein the kingpin axis is formed by a line connecting an attachment portion of the damper to the vehicle body and the pivot portion of the lower arm; or a multi-link suspension comprising: the wheel support member supporting a front wheel rotatably and five links connecting the front wheel and the wheel support member, wherein the imaginary kingpin axis is formed by an upper link, a leading link, a trailing link and a lower link which is the lower arm among the five links.

4. The rear suspension is The wheel support member supports the rear wheel so as to be freely rotatable; an upper link extending from a connecting portion on a vehicle body side toward a rear side of the vehicle and connected to the wheel support member via a pivot portion on a vehicle upper side relative to a wheel center of the rear wheel; a leading link extending from a connecting portion on a vehicle body side toward a front side of the vehicle and connected to the wheel support member via a pivot portion on a vehicle upper side relative to a wheel center of the rear wheel; a trailing link extending from a connecting portion on a vehicle body side toward the rear of the vehicle and connected to the wheel support member via a pivot portion on a lower side of the wheel center of the rear wheel; a lower link extending from a connecting portion on a vehicle body side toward a front side of the vehicle and connected to the wheel support member via a pivot portion below the wheel center of the rear wheel; a toe control link extending in a vehicle width direction from a connecting portion on a vehicle body side and connected to the wheel support member via a pivot portion, the imaginary kingpin axis is formed by vertically connecting an intersection point of imaginary extension lines of the upper link and the leading link and an intersection point of imaginary extension lines of the trailing link and the lower link, 4. A suspension device for a vehicle according to claim 1, wherein the pivot portion of the upper link and the pivot portion of the leading link are disposed adjacent to each other at a position closer to the front of the vehicle than a wheel center of a rear wheel.

5. 5. The vehicle suspension device according to claim 4, wherein in the rear suspension, the pivot portion of the upper link and the pivot portion of the leading link are arranged to overlap in the fore-and-aft direction of the vehicle in a plan view and to overlap in the up-down direction and the width direction of the vehicle in a front view.

Images