Suspension device for a vehicle

Abstract

Provided is a suspension device for a vehicle that gives a driver a good feeling of operating the vehicle by producing a smooth change in vehicle posture with respect to a steering force and an actual steering angle by suppressing roll on a steering side at the initial stage of cornering to a minimum. A front suspension (2) of a suspension device (1) for a vehicle according to the present invention has the following geometry: a caster angle (τ) of +3° to +5°, a trail (T) of +20 mm to +30 mm, a ground contact center (GC) of a tire located inward in a vehicle width direction from an intersection (GK) of a kingpin axis (K) and a ground (G), a lower camber angle (α) of a lower arm (10) of +2.8° to +7.2°, and a rear suspension (3) has the following geometry: provided with five links (50, 52, 54, 56, 58), and an imaginary kingpin axis (IK) extends near a ground contact center (GC) of a rear wheel (46) and extends vertically at -2° to 0°.

Description

TECHNICAL FIELD

[0001] The present application relates to a suspension device of a vehicle, and particularly to a suspension device of a vehicle having a front suspension that suspends a front wheel and a rear suspension that suspends a rear wheel. BACKGROUND

[0002] Patent Literature 1 discloses a strut suspension device that, in order to suppress roll of a vehicle body at the time of low-speed cornering, increases sliding resistance by pressing a piston of a shock absorber by centrifugal force generated in the vehicle body at the time of turning, thereby suppressing roll.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2020-90129

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] Here, it is well known that, at the time of cornering of a vehicle, a driver can perceive that lateral acceleration is applied to a vehicle body and roll of the vehicle body.

[0008] Further, it is also well known that the positional relationship between the intersection of the extension line of the kingpin axis or the imaginary kingpin axis of the wheel (tire) and the ground and the tire ground contact center affects the behavior of the wheel, and, for example, in designing a front suspension, it is well known that, while considering straight-ahead stability, steering reaction force, and the like, the geometry of the caster angle, the caster track, and the like formed by the kingpin axis are appropriately set.

[0009] With respect to these matters, the present inventors found that, at the initial stage of cornering when the driver starts operating the steering, roll of the vehicle body occurs mechanically not due to lateral acceleration of the vehicle body but due to the geometry of the suspension (hereinafter, referred to as "steering roll"), and thus the change in the vehicle posture at the initial stage of cornering is not smooth and hinders the driver's feeling of good operation of the vehicle.

[0010] That is, for example,

[0011] (1) when the driver operates the steering,

[0012] (2) first, "steering roll" occurs,

[0013] (3) then, yaw increases,

[0014] (4) further, roll occurs due to lateral acceleration at the time of cornering,

[0015] As above, with respect to the steering, the vehicle posture changes complicatedly and cannot become a smooth change in the vehicle posture, and this hinders the driver's feeling of good operation of the vehicle.

[0016] Here, "steering roll" refers to roll of a vehicle body mechanically generated by, when steering, exerting opposite forces in the up and down directions on the left and right sides of the vehicle body from the left and right front wheels via the left and right front suspension arms, as a result of the position of the tire ground center not changing and the amount of caster from the tire ground center, and the like, when steering, rotating the left and right front wheels about the king pin axis (imaginary king pin axis) on which a caster angle is present. SUMMARY

[0017] Therefore, the present application was completed in order to solve the above problems, and has an object to provide a suspension device for a vehicle that gives a driver a good feeling of operating the vehicle by suppressing steering roll at the initial stage of cornering to a minimum, thereby producing smooth changes in the vehicle posture with respect to the steering force and the actual steering angle.

[0018] Technical means for solving the technical problem

[0019] In order to solve the above technical problem, the present application is a suspension device for a vehicle that has a front suspension that suspends a front wheel and a rear suspension that suspends a rear wheel, the front suspension has the following geometry: a caster angle formed by a king pin axis or an imaginary king pin axis is in the range of +3° to +5° when viewed in side elevation; a caster track formed by the king pin axis or the imaginary king pin axis and a tire ground center is in the range of +20 mm to +30 mm when viewed in side elevation; an intersection of an extension line of the king pin axis or the imaginary king pin axis and the ground is located inward in the vehicle width direction from the tire ground center when viewed in front elevation; and has a lower arm that links a vehicle body and a wheel supporting member, a lower camber angle of the lower arm is in the range of +2.8° to +7.2° when viewed in front elevation, and the rear suspension has the following geometry: has five links that link the vehicle body and the wheel supporting member, and an imaginary king pin axis extends near the tire ground center of the rear wheel and extends vertically at an angle in the range of -2° to 0°.

[0020] According to the application thus configured, the front suspension has the following geometry: the caster angle is in the range of +3° to +5°, the caster trail is in the range of +20 mm to +30 mm in a side view, the intersection of the extension line of the king pin or the imaginary king pin with the ground is located inward of the tire ground center in a front view, the lower camber angle of the lower arm that links the vehicle body and the wheel supporting member is in the range of +2.8° to +7.2° in a front view, and the rear suspension has the following geometry: it has five links that link the vehicle body and the wheel supporting member, and the imaginary king pin extends near the tire ground center of the rear wheel and extends vertically at an angle in the range of -2° to 0°. Thus, the roll at the initial stage of the cornering can be minimized, the roll at the initial stage of the cornering is suppressed with respect to the steering force and the actual steering angle, and the roll attitude due to the centrifugal force is generated when entering into the stable cornering, so that a smooth vehicle attitude change can be achieved. That is, by the geometry of the front suspension and the geometry of the rear suspension, for example, after the generation of the tire lateral force and the generation of the yaw motion accompanying the same in the vehicle behavior around the three axes of the vehicle, a lateral acceleration can be applied to the vehicle and a roll motion can be generated. Here, since the imaginary king pin of the rear suspension of the application extends near the tire ground center of the rear wheel and extends vertically at an angle in the range of -2° to 0°, the roll steering tendency of the rear portion is suppressed, so that the "roll steering" of the front portion is also suppressed by suppressing the roll of the entire vehicle body.

[0021] In the above, according to the application, the "roll steering" that mechanically rolls the vehicle body at the initial stage of the cornering is minimized, the roll at the initial stage of the cornering is suppressed, and the roll attitude due to the centrifugal force is generated when entering into the stable cornering, so that the driver can feel a smooth cornering. As a result, the driver can be effectively given a feeling of well handling the vehicle.

[0022] Further, in the description of the scope of the patent claim, the description of the numerical range of "the range of A to B" includes A and B as the upper limit value and the lower limit value.

[0023] In addition, in the application, it is preferable that the front suspension has: a wheel supporting member that supports the front wheel so as to be rotatable; an upper arm that extends from a linking portion on the vehicle body side toward the vehicle width direction and is linked with the wheel supporting member via a pivot portion on the upper side of the wheel center of the front wheel; and a lower arm that extends from a linking portion on the vehicle body side toward the vehicle width direction and is linked with the wheel supporting member via a pivot portion on the lower side of the wheel center of the front wheel, and the front suspension is a double wishbone type suspension in which a line linking the pivot portion of the upper arm and the pivot portion of the lower arm forms a king pin.

[0024] According to the present application thus configured, in a double wishbone type front suspension, it is possible to effectively ensure suspension support rigidity and minimize the roll angle at the initial stage of cornering, thereby suppressing the roll at the initial stage of cornering with respect to the steering force and actual steering angle and generating a roll attitude due to centrifugal force at the time of entering into stable cornering, so that smooth vehicle attitude change can be achieved.

[0025] In addition, in the present application, it is preferable that the front suspension is a strut type suspension provided with a wheel support member that supports a front wheel so as to be rotatable, a damper that links a vehicle body and the wheel support member, and a lower arm that extends in a vehicle width direction from a linking portion on the vehicle body side and is linked to the wheel support member via a pivot portion, and that an imaginary king pin is formed by a line linking an installation portion of the damper to the pivot portion of the lower arm, or a multi-link type suspension provided with a wheel support member that supports a front wheel so as to be rotatable, and five links that link the front wheel and the wheel support member, and that an imaginary king pin is formed by an upper link, a front push link, a rear drag link, and a lower link that is a lower arm among the five links.

[0026] According to the present application thus configured, in a strut type front suspension or a multi-link type front suspension, it is possible to minimize the roll at the initial stage of suspension cornering, thereby suppressing the roll at the initial stage of cornering with respect to the steering force and actual steering angle and generating a roll attitude due to centrifugal force at the time of entering into stable cornering, so that smooth vehicle attitude change can be achieved.

[0027] In the present application, it is preferable that the rear suspension include: a wheel supporting member that supports the rear wheel so as to be rotatable; an upper link that extends from a body-side joint to a vehicle rear side and is connected to the wheel supporting member via a pivot portion on a vehicle upper side than a wheel center of the rear wheel; a front push link that extends from a body-side joint to a vehicle front side and is connected to the wheel supporting member via a pivot portion on a vehicle upper side than the wheel center of the rear wheel; a rear drag link that extends from a body-side joint to a vehicle rear side and is connected to the wheel supporting member via a pivot portion on a vehicle lower side than the wheel center of the rear wheel; a lower link that extends from a body-side joint to a vehicle front side and is connected to the wheel supporting member via a pivot portion on a vehicle lower side than the wheel center of the rear wheel; and a toe control link that extends from a body-side joint to a vehicle width direction and is connected to the wheel supporting member via a pivot portion, and that an intersection on an imaginary extension line of the upper link and the front push link and an intersection on an imaginary extension line of the rear drag link and the lower link are connected to each other, and an imaginary king pin is formed, and the pivot portion of the upper link and the pivot portion of the front push link are arranged to be close to a position on a vehicle front side than the wheel center of the rear wheel.

[0028] According to the present application thus configured, since the pivot portion of the upper link and the pivot portion of the front push link in the wheel supporting member are arranged to be close to a position on a vehicle front side than the wheel center of the rear wheel, displacement of the imaginary king pin in the rear suspension is suppressed at the time of the turning of the vehicle, and thus it is possible to further reliably suppress the roll of the front portion at the initial stage of the turning to a minimum.

[0029] In the present application, it is preferable that, in the rear suspension, the pivot portion of the upper link and the pivot portion of the front push link are arranged to overlap in a vehicle front-rear direction in a plan view and to overlap in a vehicle up-down direction and a vehicle width direction in an elevation view.

[0030] According to the present application thus configured, it is possible to reliably bring the pivot portion of the upper link and the pivot portion of the front push link in the wheel supporting member close to each other. In addition, since it is possible to suppress displacement of the imaginary king pin, it is possible to further reliably suppress the roll at the initial stage of the turning to a minimum.

[0031] Effects of the Invention

[0032] According to the suspension device of the vehicle of the present application, by suppressing the roll at the initial stage of the turning to a minimum, a smooth change in vehicle posture with respect to a steering force and an actual steering angle is generated, and thus it is possible to give a driver a good feeling of operating the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1is a perspective view of a front suspension assembly provided in a suspension device of a vehicle according to an embodiment of the present application.

[0034] Figure 2 is Figure 1 is a top view of the front suspension assembly shown in

[0035] Figure 3 is Figure 1 is a front view of the front suspension assembly shown in

[0036] Figure 4 is a top view of a front suspension on the left side of a vehicle according to the present embodiment.

[0037] Figure 5 is a side view of a front suspension on the left side of a vehicle according to the present embodiment.

[0038] Figure 6 is a front view of a front suspension on the left side of a vehicle according to the present embodiment.

[0039] Figure 7 (A) of FIG. 9 is a schematic view of a right front wheel as viewed from the front for explaining the geometry of the front suspension according to the present embodiment,(B) of FIG. 9 is a schematic view of a right front wheel as viewed from the inner side in the vehicle width direction for explaining the geometry of the front suspension according to the present embodiment. Figure 7

[0040] Figure 8 is a perspective view of a rear suspension assembly provided in a suspension device of a vehicle according to an embodiment of the present application.

[0041] Figure 9 is Figure 8 is a top view of the rear suspension assembly shown in

[0042] Figure 10 is Figure 8 is a rear view of the rear suspension assembly shown in

[0043] Figure 11 is a top view of a rear suspension on the left side of a vehicle according to the present embodiment.

[0044] Figure 12 is a side view of a rear suspension on the left side of a vehicle according to the present embodiment.

[0045] Figure 13 is a front view of a rear suspension on the left side of a vehicle according to the present embodiment.

[0046] Figure 14 is a top view for explaining the positional relationship of the respective pivot portions of the upper link and the rear trailing link in the wheel support of the rear suspension according to the present embodiment.

[0047] Figure 15is a front view for explaining positional relations of respective pivot portions of an upper link and a rear trailing link in a wheel support of a rear suspension of the embodiment, and is a diagram in which illustration of the wheel support is omitted.

[0048] Figure 16 is a line graph for explaining an example of vehicle motion at the initial stage of steering obtained through an experiment of a vehicle equipped with a suspension device of a wheel of the embodiment of the present application.

[0049] Explanation of symbols

[0050] 1 Suspension device of vehicle

[0051] 2 Front suspension

[0052] 3 Rear suspension

[0053] 4 Front subframe (suspension subframe)

[0054] 6 Front wheel

[0055] 8 Upper arm

[0056] 10 Lower arm

[0057] 12 Wheel support (wheel supporting member, hub carrier)

[0058] 22, 26 Elastic bush

[0059] 28 Pivot portion

[0060] 24, 30 Swing shaft

[0061] 36, 38 Pivot portion

[0062] 40, 42 Spherical joint

[0063] 44 Rear subframe (suspension subframe)

[0064] 46 Rear wheel

[0065] 48 Wheel support (wheel supporting member, hub carrier)

[0066] 50 Upper link (upper arm)

[0067] 52 Front push link (front push arm)

[0068] 54 Rear trailing link (rear trailing arm)

[0069] 56 Lower link (lower arm)

[0070] 58 Toe control link (toe control arm)

[0071] 70, 74 Elastic bush

[0072] 72, 76 pivot portion

[0073] 78, 80 spherical joint (knee joint)

[0074] 82, 84, 86, 88, 92 elastic bush

[0075] K king pin

[0076] IK imaginary king pin

[0077] GK intersection of king pin K and ground G

[0078] GC tire contact center (tire contact pressure center)

[0079] KO king pin offset

[0080] τ caster angle

[0081] T caster track

[0082] α camber angle

[0083] P1, P2 intersection of imaginary extension lines of each of the rear links

[0084] A3 overlapping portion of the formation range of the pivot portion (knee joint)

[0085] L3 overlapping length in the vehicle front-rear direction of the pivot portion (knee joint) DETAILED DESCRIPTION

[0086] Hereinafter, a suspension device of a vehicle according to an embodiment of the present application will be described with reference to the drawings.

[0087] First, by Figures 1 to 3 The overall structure of the front suspension of the suspension device of the vehicle according to the embodiment of the present application will be described. Figure 1 is a perspective view of a front suspension assembly provided in the suspension device of the vehicle according to the embodiment of the present application, Figure 2 is Figure 1 is a top view of the front suspension assembly shown in Figure 3 is Figure 1 is a front view of the front suspension assembly shown in

[0088] First, as Figures 1 to 3 shown, the suspension device 1 of the vehicle is provided with a left and right pair of front suspensions 2. These front suspensions 2 are installed to a front subframe (suspension subframe) 4 fixed to a vehicle body (not shown).

[0089] The front subframe 4 mainly includes: a pair of left and right side crossbeams 4a; a front crossbeam 4b that extends in the vehicle width direction to connect the front ends of these side crossbeams 4a; and a rear crossbeam 4c that extends in a U-shape when viewed from above on the rear side of the front crossbeams 4b, and extends in the vehicle width direction to connect the central portion to the rear portion of each side crossbeam 4a. Furthermore, in Figure 3 In the diagram, the front crossbeam 4b is omitted to represent the front suspension 2. The symbol CL in the diagram represents the center plane of the left and right sides of the vehicle body.

[0090] The front suspension 2 of this embodiment is a double wishbone type, comprising: an upper arm 8 mounted on the vehicle body above the front wheel 6; a lower arm 10 mounted on the side crossbeam 4a below the upper arm; and a wheel support member (wheel support component) 12 mounted on the upper arm 8 and the lower arm 10.

[0091] The upper arm 8 and the lower arm 10 swing up and down around the swing shafts 24 and 30 on the vehicle side, respectively (described later), and the wheel support 12 and the front wheel 6 travel up and down along a predetermined trajectory. The wheel support 12 is a hub bracket that supports the wheel hub 14, on which the front wheel 6 (not shown) is mounted.

[0092] Additionally, a buffer device 20 is provided in the front suspension 2. This buffer device 20 has a coil spring 16 and a damper 18 for allowing the travel of the front wheel 6 while simultaneously applying a specified force and damping force. The buffer device 20 has a long cylindrical shape in the vertical direction, with the coil spring 16 and the damper 18 arranged almost coaxially. The upper end of the buffer device 20 is mounted to the vehicle body, and the lower end of the buffer device 20 (the lower end of the damper 18) is rotatably mounted to the lower arm 10.

[0093] Furthermore, although not shown in the figure, the front suspension 2 includes a steering gear unit and a tie rod extending outward from the steering gear unit in the vehicle width direction and mounted on the wheel support 12 to steer the front wheel 6. In addition, an anti-roll bar (not shown) extending in the vehicle width direction in a manner that connects the left and right lower arms 10 is rotatably mounted on the lower arms 10 and the front crossbeam 4b.

[0094] Next, through Figures 4 to 6 Let me explain the structure of the front suspension 2 in detail. Figure 4 This is a top view of the front suspension on the left side of the vehicle in this embodiment. Figure 5 This is a side view of the front suspension on the left side of the vehicle in this embodiment. Figure 6 This is a front view of the left-side front suspension of the vehicle according to this embodiment. Here, since the basic structure of the front suspension 2 is the same on the right front wheel side and the left front wheel side, the description will focus on the left front wheel side front suspension.

[0095] First, as shown in Figures 4 to 6 , the upper arm 8 is an A-shaped arm integrally formed of a front arm portion 8a extending obliquely rearward in the vehicle width direction outward direction and a rear arm portion 8b extending obliquely forward in the vehicle width direction outward direction. The end portions of both portions of the upper arm 8 in the vehicle width direction inner side are respectively connected to the vehicle body via each of the cylindrical elastic bushings 22 having a center axis in the vehicle body front-rear direction. By these elastic bushings 22, a swing shaft 24 of the upper arm 8 extending in the vehicle front-rear direction is formed. Further, the axis of the elastic bushing 22 and the swing shaft 24 are inclined several degrees rearward of the vehicle when viewed in side view.

[0096] 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 obliquely forward in the vehicle width direction outward direction. The end portion of the front arm portion 10a of the lower arm 10 in the vehicle width direction inner side is connected to the side sill 4a via the cylindrical elastic bushing 26 having a center axis in the vehicle body front-rear direction, and the end portion of the rear arm portion 10b of the lower arm 10 in the vehicle width direction inner side and rearward of the vehicle is connected to the side sill 4a via the cylindrical elastic bushing 28 having a center axis in the vehicle body front-rear direction. By these elastic bushings 26, 28, a swing shaft 30 of the lower arm 10 extending in the vehicle front-rear direction is formed. Further, the rear arm portion 10b has a so-called Γ-shaped shape, and in the front arm portion 10a, the end portion of the rear arm portion 10b in the vehicle width direction outer side is fastened at two positions of a central portion 34 inward of the connecting portion 32 of the lower end portion of the damper 18 in the vehicle width direction (refer to Figure 1 , Figure 6 ).

[0097] The vehicle width direction outer side end portions of the upper arm 8 and the lower arm 10 are respectively connected to the wheel support 12 via the pivot portions 36, 38. Specifically, as shown in Figure 5 and Figure 6 , the wheel support 12 has an upper arm connection elongated portion 12a extending upward and a lower arm connection elongated portion 12b extending downward, and each of the arms 8, 10 is connected to the upper end portion and the lower end portion of these elongated portions 12a, 12b via the spherical joints (pintle spherical joints) 40, 42 forming the pivot portions 36, 38.

[0098] Further, as shown in Figure 4 and Figure 5 , the wheel support 12 is provided with an elongated portion (joint arm) 12c extending forward of the vehicle body for connection of a tie rod, and a tie rod (not shown) is installed at the top end portion of the elongated portion 12c.

[0099] Next, as shown in Figure 5 and Figure 6As shown, a kingpin axis K as a steering axis of the front wheel 6 is formed on a straight line (indicated by a single-dot chain line in the drawing) that links the center of the pivot portion 36 of the upper arm 8 on the front wheel 6 side and the center of the pivot portion 38 of the lower arm 10 on the front wheel 6 side of the front suspension 2.

[0100] Further, Figures 4 to 6 The symbol WC shown is the wheel center of the front wheel 6, and the symbol W is the wheel width of the front wheel 6. Figure 4 In the drawings, a central axis in the front wheel 6 width direction and a longitudinal central plane of the front wheel 6 are indicated by single-dot chain lines that pass through the wheel center WC, and a vertical axis and a horizontal axis that divide the front wheel 6 into front and rear and upper and lower portions are indicated by single-dot chain lines that pass through the wheel center WC. Figure 5 In the drawings, a central axis in the front wheel 6 width direction and a longitudinal central plane of the front wheel 6 are indicated by single-dot chain lines that pass through the wheel center WC, and a vertical axis and a horizontal axis that divide the front wheel 6 into front and rear and upper and lower portions are indicated by single-dot chain lines that pass through the wheel center WC. Figure 6 In the drawings, a central axis in the front wheel 6 width direction and a longitudinal central plane of the front wheel 6 are indicated by single-dot chain lines that pass through the wheel center WC, and a vertical axis and a horizontal axis that divide the front wheel 6 into front and rear and upper and lower portions are indicated by single-dot chain lines that pass through the wheel center WC.

[0101] Next, the main geometry of the front suspension 2 of the embodiment of the present application will be described with reference to Figures 5 to 7 (A) of the accompanying drawings. Figure 7 (A) of the accompanying drawings is a schematic view of the right front wheel as viewed from the front for explaining the geometry of the front suspension of the embodiment, and Figure 7 (B) of the accompanying drawings is a schematic view of the right front wheel as viewed from the inner side in the wheel width direction for explaining the geometry of the front suspension of the embodiment.

[0102] First, Figure 7 (A) and Figure 7 (B) of the accompanying drawings, the "tire (wheel)" is the front wheel 6, and as shown in Figure 7 (A), the distance between the intersection point GK of the kingpin axis K and the ground G and the tire ground center (tire ground pressure center) as viewed from the front is the so-called kingpin offset KO. In the embodiment, as shown in Figure 6 , the value of the kingpin offset KO is set to be positive (+) in the range of 13 mm to 22 mm, that is, the intersection point GK of the extension line of the kingpin axis K and the ground G is set to be on the inner side in the wheel width direction of the tire ground center GC as viewed from the front.

[0103] Further, in the description of the embodiment, the description of the numerical range "A to B" means that A and B are included as the upper limit value and the lower limit value. For example, the above-mentioned "range of 13 mm to 22 mm" means 13 mm or more and 22 mm or less. The same applies hereinafter.

[0104] Next, as shown in Figure 7 (B), the angle formed by the kingpin axis K and the plumb line as viewed from the side is the caster angle τ, and in Figure 5In the embodiment shown, the geometry of each arm 8, 10, damper 18, etc., is set with a caster angle τ of approximately 4°. In this embodiment, the caster angle τ of the front wheel 6 can be in the range of 3° to 5°. Furthermore, when viewed from the side, the caster angle τ is positive (+) as the direction of the upper tilt of the kingpin K towards the rear.

[0105] In addition, such as Figure 7 As shown in (B), when viewed from the side, the distance between the intersection point GK of the extension line of the kingpin shaft K and the ground G and the tire contact center GC is the backward tilt trajectory T. Figure 5 In the illustrated embodiment, the geometry of each arm 8, 10, damper 18, etc., is set with a caster trajectory T of approximately 21 mm. In this embodiment, the caster trajectory T can be in the range of +20 mm to +30 mm. Furthermore, when viewed from the side, the intersection point GK of the caster trajectory T is positive (+) when it is in front of the tire contact patch center GC.

[0106] Here, as Figure 7 As shown in (B), the caster trajectory T and the caster angle τ have the following relationship expressed in terms of trigonometric functions using the so-called hub trajectory (caster trajectory at the center of the wheel) Th and the tire radius r.

[0107] T=r×sin(τ)+Th··· Formula (1)

[0108] in,

[0109] T represents the backward tilt trajectory.

[0110] r is the tire radius.

[0111] τ is the backslope angle.

[0112] Th represents the wheel hub trajectory.

[0113] For example, when an 18-inch tire is fitted to the front wheel 6 and the wheel track is 5mm, in this embodiment, the value of the caster track T is calculated using formula (1).

[0114] 20.9mm = 25.4mm (18 inches) ÷ 2 × sin(τ)(4°) + 5mm

[0115] The value of the backward tilt trajectory T is approximately 21 mm.

[0116] Furthermore, 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 trajectory T is set to the range of +20mm to +30mm based on the values ​​of the caster angle τ, tire diameter (radius r), wheel track Th, etc.

[0117] Next, as shown in FIG. 1, in the present embodiment, the lower arm 10 is arranged so that the lower caster angle a is about 5°. In the present embodiment, the lower caster angle a of the lower arm 10 is set to a range of +2.8° to +7.2° in accordance with variations in the wheel track of the wheels, the tire width, the vehicle weight (mainly assuming different specifications of engines), and the like. Figure 6

[0118] In the present embodiment, the lower caster angle a of the lower arm 10 is set to an upward arm angle in the front arm portion 10a of the lower arm 10 from the wheel side toward the vehicle body in the front view, which is an angle of a line L connecting the center of the pivot portion 38 on the front wheel 6 side and the center axis of the elastic bush 26 on the vehicle body side with respect to a horizontal line HL. In the present embodiment, since the elastic bush 26 on the vehicle body side and the elastic bush 28 of the lower arm 10 are set to almost the same height in the vehicle front-rear direction, the lower caster angle a can also be set to an 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 force due to the lower caster angle a of the lower arm 10 becomes a resistance that suppresses the roll of the vehicle itself.

[0119] Here, as a modification example of the front suspension 2 of the present embodiment, although the illustration is omitted, instead of the above-described double wishbone type, a strut type front suspension can be adopted, which includes a wheel supporting member that supports the front wheel so as to be rotatable, a damper that links the vehicle body and the wheel supporting member, and a lower arm that extends in the vehicle width direction from the linking portion on the vehicle body side and is linked to the wheel supporting member via a pivot portion, and a king pin K is formed by a line connecting the mounting portion of the damper to the vehicle body and the pivot portion of the lower arm.

[0120] In this modification example, as shown in FIG. 1, like the above-described embodiment, it suffices to have a geometry in which a caster angle τ formed by the king pin K is in a range of +3° to +5°, a trail T formed by the king pin K and the tire ground contact center GC is in a range of +20 mm to +30 mm, an intersection point GK of an extension line of the king pin K and the ground G is located on the inner side in the vehicle width direction of the tire ground contact center GC in the front view, and a lower caster angle a of the lower arm that links the vehicle body and the wheel supporting member is in a range of +2.8° to +7.2° in the front view. Figure 7

[0121] In addition, as a further modification example of the front suspension 2 of the present embodiment, although the illustration is omitted, instead of the above-described double wishbone type, a multi-link type front suspension can be adopted, which includes a wheel supporting member that supports the front wheel so as to be rotatable and five links that link the wheel and the wheel supporting member, and an imaginary king pin is formed by the arrangement of each link of the upper link, the front push link, the rear drag link, and the lower link among the five links. ​​

[0122] In this modification, as shown in Figure 7 the same as in the above-described embodiment, it suffices to have a caster angle τ formed by the imaginary king pin axis IK in a range of +3° to +5°, a castor track T formed by the imaginary king pin axis IK and the tire ground contact center GC in a range of +20 mm to +30 mm, the intersection GK of the extension line of the imaginary king pin axis IK and the ground G to be located inward in the vehicle width direction from the tire ground contact center GC, and a lower arm angle α of the lower link connecting the vehicle body and the wheel support member to be in a range of +2.8° to +7.2° in the front view.

[0123] Next, the overall structure of the rear suspension 3 of the suspension device of the vehicle according to the embodiment of the present application will be described with reference to Figures 8 to 10 Figure 8 is a perspective view of the rear suspension assembly provided in the suspension device of the vehicle according to the embodiment of the present application, Figure 9 is a plan view of the rear suspension assembly shown in Figure 8 Figure 10 is a rear view of the rear suspension assembly shown in Figure 8

[0124] First, as shown in Figures 8 to 10 the suspension device 1 of the vehicle is provided with a pair of left and right rear suspensions 3, which are installed to a rear subframe (suspension subframe) 44 fixed to a vehicle body (not shown).

[0125] The rear subframe 44 mainly includes a pair of left and right side beams 44a, a front cross beam 44b extending so as to connect the front end portions of the side beams 44a in the vehicle width direction, and a rear cross beam 44c extending so as to connect the rear end portions of the side beams 44a in the vehicle width direction. The symbol CL in the drawing indicates a central plane of the vehicle body.

[0126] The rear suspension 3 according to the present embodiment is a multi-link suspension in which the wheel support member 48 of the rear wheel 46 is connected to the vehicle body in a strokeable manner by five independent links 50, 52, 54, 56, 58.

[0127] Specifically, the rear suspension 3 includes a front-side upper link (upper arm) 50 and a rear-side front push link (front push arm) 52, which are assumed to constitute an upper arm, a rear-side drag link (rear drag arm) 54 and a rear-side lower link (lower arm) 56, which are assumed to constitute a lower arm, and a toe control link (toe control arm) 58, which restricts the rotational displacement of the rear wheel 46 about the imaginary king pin axis IK (see Figure 12 , Figure 13 ).

[0128] ​​​The upper link 50, the front push link 52, the rear trailing link 54, and the lower link 56 swing up and down around the connecting parts (elastic bushings 70, 74, 82, and 86) on the vehicle side (described later), respectively, so that the wheel support 48 and the rear wheel 46 travel up and down along a predetermined trajectory. The wheel support 48 is a hub bracket that supports the wheel hub 60, on which the rear wheel 46 (not shown) is mounted.

[0129] Additionally, a buffer device 66 is provided, which includes a coil spring 62 and a damper 64 to allow the travel of the rear wheel 46 while simultaneously applying a specified force and damping force. The buffer device 66 has a long cylindrical shape in the vertical direction, with the coil spring 62 and damper 64 arranged almost coaxially. The upper end of the buffer device 66 is mounted to the vehicle body, and the lower end of the buffer device 66 (the lower end of the damper 64) is rotatably mounted to the lower linkage 56. Furthermore, an anti-roll bar 68, extending to connect the left and right lower linkages 56, is rotatably mounted to the rear suspension 3.

[0130] Next, through Figures 11 to 13 Let me explain the structure of the rear suspension 3 in detail. Figure 11 This is a top view of the left rear suspension of the vehicle in this embodiment. Figure 12 This is a side view of the left rear suspension of the vehicle in this embodiment. Figure 13 This is a front view of the rear suspension on the left side of the vehicle according to this embodiment. Here, since the basic structure of the rear suspension 3 is the same on the right rear wheel side and the left rear wheel side, the description will focus on the rear suspension on the left rear wheel side.

[0131] First, such as Figures 11 to 14 As shown, the inner end of the upper link 50 in the vehicle width direction is connected to the side crossbeam 44a via an elastic bushing 70 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above). When viewed from above the vehicle, the upper link 50 extends rearward in a manner that gradually moves further back from the connection point on the side of the vehicle body towards the outer side in the vehicle width direction, and the outer end of the upper link 50 in the vehicle width direction is connected to the wheel support member 48 via a pivot portion 72.

[0132] Next, the inner end of the push rod 52 in the vehicle width direction is connected to the side crossbeam 44a via an elastic bushing 74 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above). When viewed from above the vehicle, the push rod 52 extends forward in a manner that it gradually moves forward from the connection point on the side of the vehicle body towards the outer side in the vehicle width direction, and the outer end of the push rod 52 in the vehicle width direction is connected to the wheel support 48 via a pivot 76.

[0133] Thus, when viewed from above the vehicle, the two upper links 50 and 52 are configured to approach each other toward the outer side of the vehicle body, and imaginarily form an upper arm.

[0134] In this embodiment, for each pivot portion 72, 76 in the wheel support member 48 of each link 50, 52, a ball joint (pillow-type ball joint) 78, 80 described later is used.

[0135] Next, the inner end of the rear tow link 54 in the vehicle width direction is connected to the side crossbeam 44a via an elastic bushing 82 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above). When viewed from above the vehicle, the rear tow link 54 extends rearward in a manner that gradually moves further back from the connection point on the side of the vehicle body towards the outer side in the vehicle width direction, and the outer end of the rear tow link 54 in the vehicle width direction is connected to the wheel support 48 via an elastic bushing 84 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above).

[0136] Next, the inner end of the lower link 56 in the vehicle width direction is connected to the side crossbeam 44a via an elastic bushing 86 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above). When viewed from above the vehicle, the lower link 56 extends forward in a manner that it gradually moves towards the front as it moves outward from the connection point on the side of the vehicle body, and the outer end of the lower link 56 in the vehicle width direction is connected to the wheel support 48 via an elastic bushing 88 extending in the vehicle longitudinal direction (positioned at a slight angle when viewed from above).

[0137] Thus, when viewed from above the vehicle, the two lower connecting rods 54 and 56 are configured to approach each other towards the outside in the vehicle width direction, and imaginarily form the lower arm.

[0138] Next, the end of the toe control link 58 on the vehicle side is connected to the axle support 90 on the rear surface of the rear crossbeam 44c in a manner that allows it to swing freely up and down. When viewed from above the vehicle, the toe control link 58 extends forward in a manner that gradually moves further forward from the connection on the vehicle side towards the outside in the vehicle width direction, and the end of the toe control link 58 in the vehicle width direction is connected to the wheel support 48 via an elastic bushing 92.

[0139] Next, through Figures 11 to 13 The main geometry of the rear suspension 3 in an embodiment of the present invention will be explained.

[0140] First, such as Figures 11 to 13As shown, the rear suspension 3 is formed with an imaginary king pin axis IK that connects the intersection Pl of the imaginary extension line of the upper link 50 and the imaginary extension line of the front push link 52 and the intersection P2 of the imaginary extension line of the rear drag link 54 and the imaginary extension line of the lower link 56. This imaginary king pin axis IK is the instantaneous center of rotation of the turning of the rear wheel 46 in the steering direction (toe-in direction). Here, Figures 11 to 13 The symbol WC shown is the wheel center of the rear wheel 46, and Figure 11 In the middle, the single-dot chain line indicates the vertical axis that passes through the wheel center WC and divides the rear wheel 46 into front and rear and upper and lower two parts, and in the Figure 12 and Figure 13 In the middle, the single-dot chain line indicates the vertical axis that passes through the wheel center WC and divides the rear wheel 46 into front and rear and upper and lower two parts, and in the

[0141] Next, as shown in Figure 12 In the rear suspension 3 of the present embodiment, the geometry of each link 50, 52, 54, 56 is set in such a way that the imaginary king pin axis IK extends almost vertically in the vicinity of the tire ground center GC of the rear wheel 46 and on the vehicle front side in side view. In the present embodiment, the imaginary king pin axis IK extends in such a way that the intersection GK of the imaginary king pin axis IK and the ground G is within a range of -120 mm to +120 mm from the tire ground center. The inclination angle of the imaginary king pin axis IK is an angle in a range of -2° to 0°. Further, the inclination angle is positive (+) in the direction in which the upward direction of the imaginary king pin axis IK is inclined rearward in side view, and in the present embodiment, it is sufficient that the upward direction of the imaginary king pin axis IK is inclined forward by -2° from the position in which the imaginary king pin axis IK extends vertically at an angle of 0°.

[0142] Next, as shown in Figure 12 In the present embodiment, the coil spring 62 and the damper 64 are coaxial to concentrate the load received by the shock absorber 66. Further, in the present embodiment, by arranging the wheel center WC, which is the load input point from the rear wheel 46, and the pivot portion (elastic bushing) 88, which is the load support point of the lower link (lower arm) 56 that mainly receives the lateral force from the rear wheel 46, on the vertical line, that is, by making the vehicle front-rear direction displacement amount of the load input point from the rear wheel 46 and the load support point of the lower link 46 that receives the load zero (0), the internal force is made zero (0), thereby suppressing the alignment change of the rear suspension 3 with respect to the external force input from the rear wheel 46.

[0143] Next, the structure of each pivot portion 72, 76 of the upper link 50 and the front push link 52 of the embodiment of the present application will be described with reference to Figures 11 to 15 Figure 14 ​is a top view for illustrating positional relationships of the respective pivot portions of the upper link and the rear trailing link in the wheel support of the rear suspension of the embodiment, Figure 15 is a front view for illustrating positional relationships of the respective pivot portions of the upper link and the rear trailing link in the wheel support of the rear suspension of the embodiment, and is a drawing in which illustration of the wheel support is omitted.

[0144] First, as shown in Figures 11 to 14 , the respective end portions of the upper link 50 and the front push link 52 in the vehicle width direction outer side are provided with knuckle joints 78, 80, which have: a ball portion (not shown) disposed so as to be rotatable about three axes (X, Y, Z) in the end portion; a knuckle joint housing 94, 96 that holds the ball portion; and a shaft portion (not shown) that extends from the ball portion to the wheel front side.

[0145] In the embodiment, the knuckle joint housings 94, 96 are portions of a prescribed thickness (15 mm in the embodiment) that surround the respective ball portions in a cross-sectional circular shape (annular shape), and are formed by the respective end portions of the upper link 50 and the front push link 52 in the vehicle width direction outer side in the embodiment. In addition, the top end portions of the shaft portions (not shown) that extend from the ball portions are fastened to the front wall portion 48a, which is formed in the front side compared to the wheel center WC of the wheel support 12.

[0146] In the embodiment, the pivot portions 72, 76 are formed by the knuckle joints 78, 80 of such a structure.

[0147] Next, in the embodiment, as shown in Figures 11 to 15 , the pivot portion 72 of the upper link 50 and the pivot portion 76 of the front push link 52 are disposed close to each other at a position in the vehicle front side compared to the wheel center WC of the rear wheel 46.

[0148] More specifically, for example, as shown in Figure 14 , the respective pivot portions 72, 76 (knuckle joints 78, 80) have a prescribed length (indicated by symbols LI, L2) in the vehicle front-rear direction. In the embodiment, the pivot portions 72, 76 overlap in the vehicle front-rear direction when viewed in top view and side view, and the range of this overlap is indicated by a symbol L3 in the drawings.

[0149] In addition, for example, in Figure 15 , the range Al of formation of the pivot portion 72 of the upper link 50 when viewed from the vehicle front side is indicated by a phantom line, and the range A2 of formation of the pivot portion 76 of the front push link 52 is indicated by a phantom line. In the embodiment, the pivot portion 72 (knuckle joint 78) of the upper link 50 and the pivot portion 76 (knuckle joint 80) of the front push link 52 are disposed so as to overlap in the vehicle up-down direction and the vehicle width direction when viewed in front view. More specifically, in the embodiment, the pivot portion 72 of the upper link 50 and the pivot portion 76 of the front push link 52 are disposed so as to overlap in the vehicle up-down direction and the vehicle width direction when viewed in front view.Figure 15 In this case, the formation range Al of the pivot portion 72 and the formation range A2 of the pivot portion 76 overlap in the vehicle up-and-down direction and the vehicle width direction as shown by the overlapping range A3.

[0150] In addition, in the present embodiment, as shown in Figure 13 , the pivot portion 72 is arranged in close proximity to the pivot portion 76 at an angle position of about 45 degrees on the lower side in the vehicle up-and-down direction and the inner side in the vehicle width direction in the front view and the rear view.

[0151] Next, the effect of the behavior of the vehicle obtained through running experiments in a test vehicle equipped with the suspension device 1 of the vehicle of the embodiment of the present application will be described. Figure 16 is a line graph for illustrating an example of the behavior of the vehicle at the initial stage of turning obtained through experiments on a vehicle equipped with the suspension device of the embodiment of the present application. Figure 16 The vertical axis of the line graph of Figure 16 represents the value of the turning angle or the like, Figure 16 The horizontal axis of the line graph of

[0152] In the time chart shown in Figure 16 , after the start of turning (0 seconds), the turning angle (actual turning angle) first rises, and then the yaw motion of the vehicle is generated early. Subsequently, at a prescribed time, the lateral acceleration and the roll angle of the vehicle body rise almost simultaneously. Although not shown in the time scale of Figure 16 , it was also found through experiments that the roll angle which rises at the prescribed time subsequently increases linearly.

[0153] Then, as shown in Figure 16 , the generation of roll due to "turning roll" is suppressed. That is, during the time period from the start of turning to the rise of the roll angle of the vehicle body, the roll angle is suppressed to a minimum value which has no influence on the behavior of the vehicle and the driving feeling of the driver.

[0154] Here, conventionally, when the driver operates the steering as described above, the vehicle posture changes complicatedly with respect to the steering, like the first generation of "turning roll", the subsequent generation of yaw, and the subsequent generation of roll due to the lateral acceleration at the time of cornering, and a smooth change in the vehicle posture cannot be obtained. However, in the vehicle equipped with the suspension device 1 of the vehicle of the embodiment having the above-described geometry, the turning roll at the initial stage of cornering is suppressed to a minimum, and thus a smooth change in the vehicle posture with respect to the steering force and the actual turning angle can be confirmed. Figure 16

[0155] ​Next, as the design method of the suspension device of the vehicle of the present embodiment, it can also have the following stages: a stage of setting the caster τ to the range of +3° to +5°; a stage of setting the trail T to the range of +20 mm to +30 mm; a stage of setting the intersection GK of the extension line of the kingpin K or the imaginary kingpin IK and the ground G to the inside in the vehicle width direction of the tire ground center GC; a stage of setting the lower camber α of the lower arm that links the vehicle body and the wheel support 12 to the range of +2.8° to +7.2°; a stage of determining the arrangement of each arm, each link, each pivot portion, and / or the damper of the front suspension to obtain the values, the arrangement, and the kingpin K or the imaginary kingpin IK set in these stages; a stage of setting the imaginary kingpin IK to extend in the vicinity of the tire ground center GC of the rear wheel; a stage of setting the imaginary kingpin IK to extend vertically at an angle in the range of -2° to 0°; and a stage of determining the arrangement of the five links and the arrangement of each pivot portion of the rear suspension to obtain the imaginary kingpin IK set in these stages.

[0156] In addition, the above formula "T = r x sin(τ) + Th ··· Formula (1)" can also be used in such a design method.

[0157] Further, although omitted from the illustration, the automobile (vehicle) of the present embodiment is a rear wheel drive car that turns the front wheel 6 by a steering device, mounts an engine in an engine room at the front portion of the vehicle body, and arranges a differential at the rear portion of the vehicle body to drive the rear wheel 46 by an axle. Further, the present embodiment can also be applied to a front wheel drive car.

[0158] In addition, the present application is not limited to the above-described embodiments and includes other various structures. For example, in order to improve the operability, the front push link 52, the lower link 56, and the like can also be linked to the wheel support 48 via a spherical joint. In addition, the elastic bushing is not limited to a rubber bushing and can also be a resin bushing that has the required elasticity.

[0159] Next, the effects of the suspension device of the vehicle of the present embodiment and the modified example thereof will be described.

[0160] The suspension device 1 of the vehicle of the present embodiment and modified example is provided with a front suspension 2 suspending a front wheel 6 and a rear suspension 3 suspending a rear wheel 46, the front suspension has a geometry in which a caster angle τ formed by a king pin axis K or an imaginary king pin axis IK is in a range of +3° to +5° when viewed in side view, a caster trail T formed by the king pin axis K or the imaginary king pin axis IK and a tire ground center GC is in a range of +20 mm to +30 mm when viewed in side view, an intersection GK of an extension line of the king pin axis K or the imaginary king pin axis IK and a ground G is located inward in a vehicle width direction from the tire ground center GC when viewed in front view, and a lower kickup angle α of a lower arm 10 linking a vehicle body and a wheel support 12 is in a range of +2.8° to +7.2° when viewed in front view, and the rear suspension 3 has a geometry in which five links 50, 52, 54, 56, 58 link the vehicle body and the wheel support 48, and the imaginary king pin axis IK extends near the tire ground center GC of the rear wheel 46 and extends vertically at an angle in a range of -2° to 0°.

[0161] According to the present embodiment and modified example thus configured, by the respective geometries of the front suspension 2 and the rear suspension 3, the roll at the initial stage of the cornering is suppressed to a minimum, whereby with respect to the steering force and the actual steering angle, the roll at the initial stage of the cornering is suppressed and at the time of entering into the stable cornering, a roll attitude due to centrifugal force is generated, so that a smooth change in vehicle attitude can be achieved. That is, for example, after generation of tire lateral force and generation of pitch accompanying the same in the vehicle behavior around three axes of the vehicle, lateral acceleration can be applied to the vehicle and roll motion can be generated.

[0162] Here, since the vehicle body is substantially a rigid body, if the imaginary king pin axis IK at the rear is not almost vertical and extends near the tire ground center GC as in the present embodiment, the rear suspension 3 is dragged by the roll of the entire vehicle body and a roll steering tendency is generated. In contrast, in the rear suspension 3 of the present embodiment, since the geometry in which the imaginary king pin axis IK extends near the tire ground center GC of the rear wheel 46 and extends vertically at an angle in a range of -2° to 0° is provided, the roll steering tendency is suppressed, whereby by suppressing the roll of the entire vehicle body, the "roll steering" at the front is also suppressed.

[0163] Hereabove, according to the present embodiment, when the steering is operated at the initial stage of the cornering, the "roll steering" in which the vehicle body rolls is suppressed to a minimum, the roll at the initial stage of the cornering is suppressed and at the time of entering into the stable cornering, a roll attitude due to centrifugal force is generated, so that the driver can feel a smooth cornering. As a result, the driver can be effectively given a feeling of well operating the vehicle.

[0164] Further, as a driver, it is desirable that the "actual steering angle" is generated at the time of generation of the steering force (at the time of feeling of "response"), whereby the behavior of the vehicle coincides with the steering feeling of the driver. This can be obtained by appropriately adjusting the "no-feeling zone" of the steering, whereby the above-mentioned effects of the present embodiment can be more effectively obtained.

[0165] Further, according to the present embodiment, the front suspension 2 is provided with: a wheel support member 12 that supports the front wheel 6 so as to be rotatable; an upper arm 8 that extends in the vehicle width direction from the body-side joint portion and is joined to the wheel support member 12 via the 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 the body-side joint portion and is joined to the wheel support member 12 via the pivot portion 38 on the lower side of the wheel center WC of the front wheel 6, and is a double wishbone type suspension that forms the king pin K by a line that joins the pivot portion 36 of the upper arm 8 and the pivot portion 38 of the lower arm 10.

[0166] According to the present application thus configured, in the double wishbone type front suspension 2, it is possible to effectively ensure the suspension support rigidity and minimize the steering inclination at the initial stage of the roll, whereby the roll at the initial stage of the roll is suppressed with respect to the steering force and the actual steering angle and the roll attitude due to the centrifugal force is generated at the time of entering into the stable roll, and thus a smooth change in the vehicle attitude can be achieved.

[0167] Further, according to the modified example of the present embodiment, the front suspension is a strut type suspension provided with: a wheel support member 12 that supports the front wheel so as to be rotatable; a damper that joins the vehicle body and the wheel support member; and a lower arm that extends in the vehicle width direction from the body-side joint portion and is joined to the wheel support member via the pivot portion, and forms the king pin K by a line that joins the mounting portion of the damper to the vehicle body and the pivot portion of the lower arm, or a multi-link type suspension provided with: a wheel support member that supports the front wheel so as to be rotatable; and five links that join the front wheel and the wheel support member, and forms an imaginary king pin IK by the upper link, the front push link, the rear drag link, and the lower link (lower arm) among the five links.

[0168] According to the modified example of the present embodiment thus configured, in the strut type front suspension or the multi-link type front suspension, it is possible to minimize the steering roll at the initial stage of the suspension roll, whereby the roll at the initial stage of the roll is suppressed with respect to the steering force and the actual steering angle and the roll attitude due to the centrifugal force is generated at the time of entering into the stable roll, and thus a smooth change in the vehicle attitude can be achieved.

[0169] Further, according to the present embodiment and modification, the rear suspension 3 is provided with: a wheel support member 48 that supports the rear wheel 46 so as to be rotatable; an upper link 50 that extends from a body-side joint portion to the vehicle rear side and is joined to the wheel support member 48 via a pivot portion 72 on the vehicle upper side relative to the wheel center WC of the rear wheel 46; a front push link 52 that extends from a body-side joint portion to the vehicle front side and is joined to the wheel support member 48 via a pivot portion 76 on the vehicle upper side relative to the wheel center WC of the rear wheel 46; a rear drag link 54 that extends from a body-side joint portion to the vehicle rear side and is joined to the wheel support member 48 via a pivot portion (elastic bushing 84) on the vehicle lower side relative to the wheel center WC of the rear wheel 46; a lower link (lower arm) 56 that extends from a body-side joint portion to the vehicle front side and is joined to the wheel support member 48 via a pivot portion (elastic bushing 88) on the vehicle lower side relative to the wheel center WC of the rear wheel 46; and a toe control link 58 that extends from a body-side joint portion to the vehicle width direction and is joined to the wheel support member 48 via a pivot portion (elastic bushing 92), and an imaginary king pin axis IK is formed by joining the intersection Pl on the respective imaginary extension lines of the upper link 50 and the front push link 52 and the intersection P2 on the respective imaginary extension lines of the rear drag 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 front push link 52 are arranged so as to be close to the position on the vehicle front side relative to the wheel center WC of the rear wheel 46.

[0170] According to the present embodiment and modification thus configured, in the turning of the vehicle, the displacement of the imaginary king pin axis IK in the rear suspension 3 can be suppressed, and the roll at the initial stage of the turning can be further reliably suppressed to a minimum.

[0171] Further, according to the present embodiment and modification, since in the rear suspension 3, the pivot portion 72 (pillow ball joint 78) of the upper link 50 and the pivot portion 76 (pillow ball joint 80) of the front push link 52 are arranged so as to overlap in the vehicle front-rear direction in plan view and overlap in the vehicle up-down direction and the vehicle width direction in elevation view, the pivot portion 72 (pillow ball joint 78) of the upper link 50 and the pivot portion 76 (pillow ball joint 80) of the front push link 52 can be further reliably brought close.

Claims

1. A suspension device of a vehicle, provided with a front suspension that suspends a front wheel and a rear suspension that suspends a rear wheel, characterized in that, the front suspension has the following geometry: a caster angle formed by a kingpin or an imaginary kingpin is in a range of +3° to +5° when viewed in side view; a caster track formed by the kingpin or the imaginary kingpin and a center of tire ground contact is in a range of +20 mm to +30 mm when viewed in side view; an intersection of an extension line of the kingpin or the imaginary kingpin and a ground surface is located inward in a vehicle width direction from the center of tire ground contact when viewed in front view; a lower arm that links a vehicle body and a wheel supporting member has a lower camber angle in a range of +2.8° to +7.2° when viewed in front view, the rear suspension has the following geometry: five links that link the vehicle body and the wheel supporting member, and an imaginary kingpin that extends near a center of tire ground contact of the rear wheel and extends vertically at an angle in a range of -2° to 0°.

2. The suspension device of a vehicle according to claim 1, characterized in that, the front suspension is provided with: the wheel supporting member that supports the front wheel so as to be rotatable; an upper arm that extends from a linking portion on the vehicle body side toward the vehicle width direction and is linked to the wheel supporting member via a pivot portion on the upper side of the wheel center of the front wheel; and the lower arm that extends from a linking portion on the vehicle body side toward the vehicle width direction and is linked to the wheel supporting member via a pivot portion on the lower side of the wheel center of the front wheel, the front suspension is a double wishbone type suspension that forms the kingpin by a line that links the pivot portion of the upper arm and the pivot portion of the lower arm.

3. The suspension device of a vehicle according to claim 1, characterized in that, the front suspension is a strut type suspension or a multi-link type suspension, the strut type suspension is provided with: the wheel supporting member that supports the front wheel so as to be rotatable; a damper that links the vehicle body and the wheel supporting member; and the lower arm that extends from a linking portion on the vehicle body side toward the vehicle width direction and is linked to the wheel supporting member via a pivot portion, the kingpin is formed by a line that links a mounting portion of the damper to the vehicle body and the pivot portion of the lower arm, the multi-link type suspension is provided with: the wheel supporting member that supports the front wheel so as to be rotatable; and five links that link the front wheel and the wheel supporting member, and the imaginary kingpin is formed by an upper link, a front push link, a rear drag link, and a lower link that is the lower arm among the five links.

4. The suspension device of a vehicle according to any one of claims 1 to 3, characterized in that, the rear suspension is provided with: the wheel supporting member that supports the rear wheel so as to be rotatable; an upper link that extends from a linking portion on the vehicle body side toward the rear side of the vehicle and is linked to the wheel supporting member via a pivot portion on the upper side of the wheel center of the rear wheel; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a front push link extending from a link part on the vehicle body side to the front side of the vehicle and linked to the wheel supporting member via a pivot part on the upper side of the vehicle than the wheel center of the rear wheel; a rear drag link extending from a link part on the vehicle body side to the rear side of the vehicle and linked to the wheel supporting member via a pivot part on the lower side of the vehicle than the wheel center of the rear wheel; a lower link extending from a link part on the vehicle body side to the front side of the vehicle and linked to the wheel supporting member via a pivot part on the lower side of the vehicle than the wheel center of the rear wheel; and a toe control link extending from a link part on the vehicle body side to the width direction of the vehicle and linked to the wheel supporting member via a pivot part, the imaginary kingpin axis is formed by linking the intersection points on the imaginary extension lines of the upper link and the front push link and the intersection points on the imaginary extension lines of the rear drag link and the lower link, the pivot part of the upper link and the pivot part of the front push link are disposed close to the position on the front side of the vehicle than the wheel center of the rear wheel.

5. The suspension device of a vehicle according to claim 4, wherein in the rear suspension, the pivot part of the upper link and the pivot part of the front push link are disposed so as to overlap in the front-rear direction of the vehicle in plan view and overlap in the up-down direction of the vehicle and the width direction of the vehicle in elevation view.

Images