JP2712150B2 - Car suspension - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension system for a motor vehicle, and more particularly to an independent suspension system in which a carrier on which wheels are mounted is supported by a pair of trailing arms arranged vertically. (Prior Art) Full trailing using a full trailing arm which is pivotally attached to the vehicle body at inner and outer connecting portions provided at intervals in the lateral direction of the vehicle body as a type in which wheels are independently suspended. Arm type (for example, Japanese Utility Model Laid-Open No. 59-2607), a semi-trailing arm type using a semi-trailing arm in which inner and outer connecting portions are arranged obliquely with respect to the center line of the vehicle body (for example, Japanese Utility Model Application Laid-open No. 58-15509), a double wishbone type using bifurcated arms arranged at intervals above and below (for example, Japanese Utility Model Application Laid-open No.
JP-A-65106) and a MacPherson strut type using a shock absorber as a strut (for example, Japanese Utility Model Laid-Open No. 58-112604). (Problems to be Solved by the Invention) In the full trailing arm type suspension device, when the wheel moves up and down, the change of the camber and tread is small. As a result, the cornering force is affected, so that it is limited to enhance the turning limit performance. In the case of the semi-trailing arm type, the double wishbone type or the MacPherson strut type, the camber changes as the wheel moves up and down, so the turning limit performance is improved, but the tread changes at the same time as the camber changes. When the change in the tread is large, a lateral force is generated in the tire due to the vertical movement of the wheel, which may adversely affect ride comfort, running stability, tire wear, and the like. SUMMARY OF THE INVENTION It is an object of the present invention to provide a suspension system for an automobile in which a camber can be changed when a wheel moves up and down, while a ground camber and a tread change little. (Means for Solving the Problems) The suspension system for an automobile according to the present invention basically includes a carrier for supporting wheels, and a pair of trailing arms arranged at an interval vertically. A pair of trailing arms pivotally coupled to the vehicle body at inner and outer coupling portions and pivotally coupled to the carrier at respective rearward coupling portions. The center of the inner connecting portion is located lower than the center of the outer connecting portion. When the pair of trailing arms is a full trailing arm type, these trailing arms are:
A straight line passing through the center of the rear connecting portion of the upper trailing arm has a slope corresponding to the slope of a straight line connecting the centers of the inner and outer connecting portions of the upper trailing arm. A straight line passing through the center of the rear connecting portion of the lower trailing arm, the straight line having a slope corresponding to the tilt of a straight line connecting the centers of the inner and outer connecting portions of the lower trailing arm. Are arranged so that the left and right wheels intersect in a rear view of the vehicle body, and the intersection is located on or near the ground.
The intersection is the instantaneous center of rotation of the carrier. When the pair of trailing arms is of a semi-trailing arm type, the trailing arm may be a straight line connecting the center of the inner and outer connecting portions of the upper trailing arm and the upper tray. A straight line extending from the intersection with the vertical plane extending in the lateral direction of the vehicle body including the center of the rear connection portion of the ring arm to the center of the rear connection portion of the upper trailing arm is formed by the lower trailing arm. From the intersection of a straight line connecting the centers of the inner and outer connecting portions of the arm and the vertical plane extending in the lateral direction of the vehicle body including the center of the rear connecting portion of the lower trailing arm, The straight line extending to the center of the rear connecting portion of the trailing arm intersects with the left and right wheels in rear view of the vehicle body, and the intersection is on or near the ground. It is arranged so as to be located. The intersection located on or near the ground is the instantaneous center of rotation of the carrier. (Operation and Effect) The instantaneous center of rotation of the wheel can be located near the wheel supported by the suspension. As a result, when the wheel bounces or rebounds, the camber angle greatly changes from negative to positive, but the change in the ground camber of the wheel is small and is kept almost constant, so when turning, the cornering force of the outer wheel is effectively drawn out The turning limit characteristics can be improved. The instantaneous rotational center of the wheel will be located on or near the ground even if the wheel bounces or rebounds, but the wheel will be tangential to the circle centered on the instantaneous rotational center,
That is, to move in a direction substantially perpendicular to the ground,
Tread change during bounce or rebound is extremely small. Thereby, the straightness of the vehicle is improved. Since the instantaneous center of rotation of the wheel always exists on or near the ground, the thrust load of the wheel due to uneven road surface
All the springs provided on the suspension device receive the spring, and the riding comfort is improved. (Embodiment) A suspension device 10 shown in FIGS. 1 and 2 includes a carrier 12 for supporting wheels, and a pair of trailing arms 14 and 16 of a full trailing arm type which are arranged at an interval vertically. And The carrier 12 has a structure known per se, and has a hub
The hub 18 has wheels 20 mounted thereon. The upper trailing arm 14 has an inner connecting portion 15a,
It has an outer connecting portion 15b and a rear connecting portion 15c, and the inner and outer connecting portions 15a and 15b are arranged in the lateral direction of the vehicle body,
Each connecting portion is connected to the vehicle body 22 via a rubber bush (not shown).
To be swingably coupled to. The rear connecting part 15c is in the form of a ball joint, by means of which the carrier 12 is coupled to the upper trailing arm 14 so as to be rotatable in three dimensions. The centers of the connecting portions 15a, 15b, and 15c are D, E, and G, respectively, and the center D of the inner connecting portion 15a is
Is located below the center E of the outer connecting portion 15b. The lower trailing arm 16 has an inner connecting portion 17a,
It has an outer connecting portion 17b and a rear connecting portion 17c, and the inner and outer connecting portions 17a, 17b are arranged in the lateral direction of the vehicle body,
Each connecting portion is connected to the vehicle body 22 via a rubber bush (not shown).
To be swingably coupled to. The rear connecting part 17c is in the form of a ball joint, by means of which the carrier 12 is connected to the lower trailing arm 16 so as to be rotatable three-dimensionally. The centers of the connecting portions 17a, 17b, and 17c are B, C, and F, respectively, and the center B of the inner connecting portion 17a is
Is located below the center C of the outer connecting portion 17b. A tie rod 24 as a toe direction determining member is coupled to the carrier 12 by a ball joint 26 so as to be rotatable three-dimensionally. The tie rod 24 is disposed in the front-rear direction of the vehicle body, and is coupled to the vehicle body at its front end by a ball joint 28 so as to be three-dimensionally rotatable. Ball joint 2
The centers of 6, 28 are I and H, respectively. The ball joints 26, 28 are positioned so that their centers I, H are not below the axis of the hub 18. The pair of trailing arms 14 and 16 are arranged as follows. In other words, the inner and the connecting portion 15a of the outer, center D of 15b, the rear connection of a tilt and above the trailing arm 14 to match the slope of the straight line L ₁ connecting the E of the upper trailing arm 14 A straight line L ₂ passing through the center G of the portion 15 c is connected to the inner and outer connecting portions 17 of the lower trailing arm 16.
a, 17b center B, the rear of the connecting portion of the straight line L ₃ and has a slope matching the slope of the lower trailing arms 16 connecting the C of
The straight line L ₄ passing through the center F of 17c, intersection between the left and right wheels in the vehicle body in a rear view, and the intersection A is arranged so as to be positioned on or in the vicinity of the ground K. Here, the intersection in the rear view of the vehicle body means that the two straight lines L ₂ and L ₄ may be located close to each other or coincide with each other in the plan view without intersecting. In the suspension device 10 shown in FIGS. 1 and 2, since the upper and lower trailing arms 14 and 16 are of a full trailing type, each straight line extends in the lateral direction of the vehicle body through each center, and It will be orthogonal to the center line M. for that reason,
As shown in FIG. 2, there may be a distance S between the centers G and F in the front-rear direction depending on the mounting positions of the connecting portions 15c and 17c, and the straight lines L ₂ and L ₄ passing through these centers are planes. Do not meet in sight. When the distance S becomes zero, a straight line
L ₂ and L ₄ coincide. However, they meet in rear view. The suspension device 30 shown in FIGS. 4 and 5 includes a carrier 32 for supporting wheels and a pair of trailing arms 34, 36 of the seri trailing arm type, which are vertically spaced. The carrier 43 has a structure known per se, like the carrier 12, and has a hub 38.
40 is installed. The upper trailing arm 34 has an inner connecting portion 35a,
It has an outer connecting portion 35b and a rear connecting portion 35c. The inner and outer connecting portions 35a and 35b are arranged obliquely with respect to the lateral direction of the vehicle body, that is, the outer connecting portion 35b is disposed so as to be located forward of the inner connecting portion 35a. It is swingably coupled to the vehicle body 42 via a rubber bush (not shown). The rear connecting portion 35c is in the form of a ball joint, by means of which the carrier 32 is connected to the upper trailing arm 34 so as to be rotatable three-dimensionally. The centers of the connecting portions 35a, 35b, 35c are D, E, G, respectively.
The center D of the inner connecting portion 35a is located behind and below the center E of the outer connecting portion 35b. The lower trailing arm 36 has an inner connecting portion 37a,
It has an outer connecting portion 37b and a rear connecting portion 37c. The inner and outer connecting portions 37a and 37b are arranged obliquely to the lateral direction of the vehicle body, that is, the outer connecting portion 37b is disposed forward of the inner connecting portion 37a, and each connecting portion is made of rubber. Through a bush (not shown).
The rear connecting part 37c is in the form of a ball joint, by means of which the carrier 32 is connected to the lower trailing arm 36 so as to be rotatable in three dimensions. The centers of the connecting portions 37a, 37b, 37c are B, C, and F, respectively, and the center B of the inner connecting portion 37a is located behind and below the center C of the outer connecting portion 37b. The tie rods 44 rotatably connected to the carrier 32 three-dimensionally by a ball joint 46 are arranged in the front-rear direction of the vehicle body. The tie rod 44 is three-dimensionally rotatably connected to the vehicle body at its forward end by a ball joint 48. The centers of the ball joints 46 and 48 are I and H, respectively. The ball joints 46, 48 are positioned such that their centers I, H do not fall below the axis of the hub 38. The pair of trailing arms 34 and 36 are arranged as follows. That is, the body tie connection portion 35a of the inner and outer upper trailing arms 34, the center D of 35b, the center G of the rear of the connecting portion 35c of the straight line N ₁ and the upper trailing arm 34 which connects the E from the intersection Q of the vertical plane P extending in the transverse direction, the straight line N ₂ extending to the center G of the rear of the connecting portion 35c of the upper trailing arm 34, the lower trailing arms 36
Inner and the connecting portion 37a of the outer, 37b center B of the connecting portion behind the straight line N ₃ and a lower trailing arms 36 connecting the C 37
include center F of c from the intersection R between the vertical plane P extending in the vehicle body transverse direction, the straight line N ₄ extending to the center F of the rear of the connecting portion 37c of the lower trailing arms 36, left and right in the vehicle body rear view And the intersection point A is arranged on or near the ground K. here,
Intersecting in the rear view of the vehicle body means that
This means that the straight lines N ₂ and N ₄ may be located close to each other or coincide with each other without intersecting. (Operation of the embodiment) As shown in FIGS. 3 and 6, when the wheel 20 is neutral, the position of the intersection A, the center G of the connecting portion 15c, the center F of the connecting portion 17c, and the contact point J of the wheel 20 are set. Was displaced to the positions A ₁ , G ₁ , F ₁ and J ₁ when bound, and A ₂ , G ₂ , F ₂ and F ₂ when rebounded, respectively.
The J _2. However, the centers B, C, D, and E do not displace because they belong to the vehicle body side. As is clear from FIG. 3 and FIG.
In any of the neutral state (J), the bounce state (J ₁ ), and the rebound state (J ₂ ), the vehicle body is located at substantially the same position in the lateral direction of the vehicle body. This indicates that the tread does not change based on the bounce and rebound, and the cause is that the instantaneous rotation centers A ₁ and A ₂ at the time of bounce and rebound are almost on the ground K at that time. It is. On the other hand, the camber angle, as shown on wheels 20, 40,
It changes greatly from a negative value at the time of bounce to a positive value at the time of rebound. This is because the instantaneous rotation center A exists near the wheels 20 and 40. FIGS. 7 and 8 show how the tread changes with the bounce and rebound in comparison with the McPherson strut type suspension. In FIGS. 7 and 8, the tread T _{1 in} the case of the full trailing arm and the case of the semi-trailing arm are shown. tread T ₂ are, in comparison with the tread T ₃ in the case of MacPherson strut, the degree of the change it can be seen that significantly less. Also, in FIG. 9 showing how the ground camber changes with the bounce and rebound, the ground camber T _{4 in} the case of the present invention has a smaller change than the ground camber T ₅ in the case of the Maspherson strut. I understand. In the illustrated embodiment, the tie rods 24 in the case of the full trailing arm and the tie rods 44 in the case of the semi-trailing arm are disposed in the front-rear direction of the vehicle body and are located above the axis of the hub. Works. The following description is for the case of a semi-trailing arm, but the same applies to the case of a full trailing arm. During braking, a rearward force is applied to the contact point J of the wheel 40 as shown in FIG. At this time, the center F tends to move backward and the center G tends to move forward. However, since the tie rods 44 are arranged in the front-rear direction, the center G and the coupling center I of the tie rods to the carrier 32 are different. The toe direction of the wheel 40 is controlled. In this case, since the centers H and I before and after the tie rod 44 are ball joints and do not change, the center G is displaced diagonally forward as indicated by an arrow, and the wheels 40 tend to toe-in. During driving, a forward force is applied to the wheel center as shown in FIG. At this time, the centers F and G try to be displaced forward, but for the same reason as described above, the center I is not displaced. Becomes As shown in Fig. 12, lateral force (cornering force)
Is input to the grounding point J, the center F receives a force inward of the vehicle body and the center G receives a force outward. At this time, since the upper trailing arm 34 and the lower trailing arm 36 are connected to the vehicle body via rubber bushes, the center F
Is displaced inward and rearward, and the center G is displaced outward and forward. For the same reason as described above, the center I is not displaced, so that only the center G is displaced forward and the wheels 40 tend to toe-in.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a rear view of a full trailing type suspension,
FIG. 2 is a plan view of the same, FIG. 3 is a rear view showing the bounce, camber and tread of the suspension of FIG. 1 during rebound,
FIG. 4 is a rear view of a semi-trailing type suspension system,
FIG. 5 is a plan view of the same, FIG. 6 is a rear view showing the camber and tread at the time of bouncing and rebounding the suspension of FIG.
7 to 9 are graphs comparing the tread and camber at the time of bounce and rebound with the conventional tread, and FIG. 10 shows the behavior at the time of braking, where a is a plan view, b is a side view, FIG. 11 shows the behavior at the time of driving, a is a plan view,
FIG. 12B is a side view, and FIG. 12 is a view showing a behavior at the time of a cornering force action. 10, 30: suspension system, 12, 32: carrier, 14, 16, 34, 36: trailing arm, 24, 44: tie rod.

Claims (1)

(57) [Claims] A carrier that supports the wheels, and a pair of trailing arms that are vertically spaced from each other and are swingably coupled to the vehicle body at respective inner connecting portions and outer connecting portions, and And a pair of full trailing arm type trailing arms swingably coupled to the carrier at a rear connection portion of the rear connection arm, the center of the inner connection portion of the trailing arm being the outer connection portion. The pair of trailing arms are aligned with the inclination of a straight line connecting the center of the inner connecting portion and the center of the outer connecting portion of the upper trailing arm. A straight line passing through the center of the rear connecting portion of the upper trailing arm,
The rear connection of the lower trailing arm has a slope that matches a slope of a straight line connecting the center of the inner connection part and the center of the outer connection part of the lower trailing arm. A vehicle suspension device arranged so that a straight line passing through the center of the part intersects between the left and right wheels in a rear view of the vehicle body, and the intersection is located on or near the ground. 2. A carrier that supports the wheels, and a pair of trailing arms that are vertically spaced from each other and are swingably coupled to the vehicle body at respective inner connecting portions and outer connecting portions, and And a pair of semi-trailing arm type trailing arms that are swingably coupled to the carrier at a rear connecting portion of the trailing arm, the center of the inner connecting portion of the trailing arm being the outer connecting portion. A pair of trailing arms, the pair of trailing arms is connected to a straight line connecting the center of the inner connecting portion and the center of the outer connecting portion of the upper trailing arm and the upper A straight line extending from the intersection with the vertical plane extending in the lateral direction of the vehicle body including the center of the rear connection portion of the trailing arm to the center of the rear connection portion of the upper trailing arm, A lateral direction of the vehicle body including a straight line connecting the center of the inner connecting portion of the lower trailing arm and the center of the outer connecting portion and the center of the rear connecting portion of the lower trailing arm. A straight line extending from the intersection with the extending vertical surface to the center of the rear connecting portion of the lower trailing arm intersects the left and right wheels in rear view of the vehicle body, and the intersection is on or near the ground. Suspension of a car arranged to be located at