JPH0238116A - Rear suspension for vehicle - Google Patents

Abstract

PURPOSE:To improve rigidity, durability and the like by forming a swing arm for connecting a body to a wheel support member in such a way as to have a closed sectional structure, and connecting the inner end of an upper arm to the body via a plurality of bushes positioned along the lengthwise direction of the body. CONSTITUTION:A swing arm 12 in a rear suspension 10 is formed to have a hollow box type closed sectional structure, and the front end 12a of the swing arm 12 is axially connected to a body frame 16, while the rear end 12b thereof axially connected to the wheel carrier 11 of a rear wheel 2, respectively. Also, an upper arm 13 forms a passage hole of a damper 17, while the outer end 13b of the arm 13 is supported on the upper end of the wheel carrier 11 and the inner end 13c thereof supported on a sub-frame 18 respectively via a support mechanism 19 having a plurality of elastic bushes and the like. Furthermore, a lower arm 14 has the outer end 14a supported on the lower end of the wheel carrier 11 and the side end 14b thereof on the sub-frame 18 respectively via the elastic bushes.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an independent rear suspension.

(Prior Art) As shown in FIG. 4, a suspension engine for a vehicle has a rear end fixedly attached to a wheel support member 2 that supports a wheel 1, and a front end pivotally supported by a body frame (not shown). A trailing arm 3 is disposed above the center of the wheel, one end of which is connected to the wheel support member 2, and the other end of which is connected to the subframe (not shown).
Lateral link supported by 4. The lateral links 5 and 6 are disposed at the front and rear of the lower side with respect to the wheel center, each one end being supported by the wheel support member 2, and each other end being pivotally supported by the subframe. There is something.

In a suspension system configured by one trailing arm 3 and three lateral links 4 to 6, when the toe control function is exerted by the three lateral links 4 to 6, the trailing It is common to use a member that allows the arm 2 to bend, and usually a leaf spring is used.

In addition, in the conventional suspension described above, in order to make it easy for the circular links 4 to 6 to swing in all directions, both the vehicle body side and the wheel support member side are supported by a single pivoting means.

(Problem to be solved by the invention) However, in the above conventional suspension,
The bushing on the vehicle body side of the lateral link 3 must receive the lateral force applied to the wheel l and the reaction force acting on the upper and lower blades, and as a result, there is a problem in that the life of the bushing is prematurely reduced.

In addition, three lateral links 4 to 6 that support the wheel 1 are provided at one location above the wheel center and distributed at two locations below, front and rear, with respect to the center of the wheel. This has to be applied at one point at a time, which reduces the supporting rigidity of the wheel 1, leading to a problem of reduced steering stability.

The present invention was made in order to solve the above-mentioned problems, and the trailing arm is made into a rigid body, the upper one of the lateral links is located almost directly above the wheel center axis, and the support points on the vehicle body side are located relatively close to each other. An object of the present invention is to provide a rear suspension for a vehicle in which the supporting rigidity of a wheel is increased and the life of a bushing is extended by having a two-support point configuration set in the longitudinal direction.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a wheel support member that rotatably supports a wheel; a swing arm having a front end connected to the vehicle body; an upper arm extending in the vehicle width direction and connecting the upper part of the wheel support member to the vehicle body; and a lower arm extending in the vehicle width direction and connecting the upper part of the wheel support member to the vehicle body. In the vehicle suspension system, the swing arm is configured to have a closed cross-section structure, and a bushing is provided at the connecting portion of at least one of the two lower arms, The inner ends of the upper arm are connected to the vehicle body through two bushings that are close to each other and extend along the longitudinal direction of the vehicle body.

(Function) Since the swing arm has a box-type closed cross-section structure, it has high rigidity, resists lateral forces, etc., and reduces the amount of displacement of each arm in the front-rear direction.

Since the inner ends of the upper arms are connected to the vehicle body via elastic bushings disposed close to each other, the lateral forces acting on the upper part of the wheel support member are distributed and borne by the elastic bushings. Therefore, the rigidity of the support mechanism is improved, and the elasticity of each elastic bushing can be increased to make it softer.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2 show a rear suspension for a vehicle according to the present invention, and the rear suspension 10 includes a wheel support member (
The wheel carrier 11 rotatably supports the rear wheel 2. The wheel carrier 11 rotatably supports the rear wheel 2.

The trailing arm 12 has an L-arm shape and extends substantially along the longitudinal direction of the vehicle. The front end 12a of the trailing arm 12 is pivotally supported at a predetermined position of the body frame 16 via an elastic bush (not shown) so as to be rotatable in the vertical direction, and the rear end 12b is approximately the inner surface of the wheel carrier 11 on the vehicle body side. It is firmly welded and fixed in the center. The trailing arm 12 is formed into a hollow box-shaped closed cross-sectional structure and has great rigidity.

The upper arm 13 has a so-called L-arm shape in which a damper insertion hole 13a for avoiding interference with the damper I7 is formed substantially in the center, and is arranged substantially parallel to an axle (not shown). The outer end 13b on the wheel side is connected to the wheel carrier 11
It is supported rotatably in all directions via a pole joint at the upper end and directly above the center of the axle, and the inner end 13c on the vehicle body side is attached to a predetermined position of the subframe 18 via a support mechanism 19. It can be installed automatically in the vertical direction.

As shown in the third section of the support mechanism 19, the device mounting parts 21 and 22 are composed of an inner cylinder 20, a front mounting part 21, and a rear mounting part 22, which are arranged along the longitudinal direction of the vehicle. Each of the bushings is composed of a cylindrical elastic bushing 23, 24, and an outer cylinder 25, 26 that is fitted onto these bushings and non-rotatably vulcanized and bonded thereto. Each mounting part 21,22 is arranged in close proximity. That is, the elastic bushing 2 of the front mounting portion 21
3 is fitted over the front part of the cylinder 20, and the elastic bushing 24 of the rear mounting part 22 is fitted onto the rear part of the cylinder 20 and is vulcanized and bonded so as not to rotate. Furthermore, the front mounting part 2
The outer cylinder 25 of the upper arm 13 is press-fitted into the cylindrical part 13d firmly welded and fixed to the front side of the inner end 13c of the upper arm 13, and the outer cylinder 26 of the rear mounting part 22 is attached to the inner end 1 of the upper arm 13.
It is press-fitted into a cylindrical portion 13e that is firmly welded and fixed to the rear side of the cylindrical portion 3c.

Therefore, with respect to the outer end 13b of the upper arm 13, that is, the center position of the rear wheel 2, the front mounting portion 21 is slightly biased forward, and the rear end mounting portion 22 is slightly biased backward.

The spring constants (hereinafter simply referred to as spring constants) of the elastic bushes 23 and 24 in a direction perpendicular to the axial direction (in the direction of arrow A in FIG. 3) are set to -.

The lower arm 14 has an arm shape and is arranged substantially along the vehicle width direction, and the outer end 14a on the wheel side is connected via a ball joint to the lower end of the wheel carrier 11 and at a position rearward of the center of the rear wheel 2. , the vehicle body side end 14b is the subframe 1
8 are rotatably attached to predetermined positions via elastic bushes (not shown).

The wheel carrier 11 rotates using a virtual axis connecting the ball joints of the outer ends 14a and 13b of the lower arm 14 and the upper arm 13 on the wheel side as a virtual kingpin axis. Further, the change in the inclination state of the virtual kingpin axis in the vehicle width direction is related to the change in the camber angle, and the camber angle change characteristics of the suspension 10 are mainly determined by the arm lengths of the upper arm 13 and the lower arm 14, each mounting position, Determined by each mounting angle line.

The assist arm 15 has an I-arm shape with a shorter arm length than the lower arm 14, and is arranged along the vehicle width direction. The outer end (wheel side) 15a of the assist arm 15 is located at the lower end of the wheel carrier 11 and in front of the center of the rear wheel 2 via a ball joint, and the inner (vehicle body side) end 15b is connected to the subframe at a predetermined position for one day. They are rotatably attached to the respective positions via elastic bushings. This assist arm 15 controls the rotation of the wheel carrier 11 around the virtual kingpin axis by linking and interfering with the other arms 12 to 14. Therefore, the toe angle change characteristic is mainly determined by the arm length, mounting position, mounting angle, etc. of the assist arm 15.

This rear suspension 10 counteracts rotational force and longitudinal force acting on the rear wheel 2 by a trailing arm 12, and counteracts stress etc. by an upper arm 13, a lower arm 14, and an assist arm 15.

The action will be explained below.

Since the trailing arm 12 has a box-shaped closed cross-sectional structure, it has great locking properties and can sufficiently resist not only the rotational force and longitudinal force of the rear wheel 2 but also lateral force and the like. For this reason,
It is possible to reduce the manual load applied to each elastic bushing (only elastic bushings 23 and 24 are shown) disposed at the inner ends 13c, 14b, and 15b of the upper arm 13, lower arm 14, and assist arm 15 on the vehicle body side. , assist arm 1 that regulates the toe angle change of the suspension lO
The load input to the elastic bushing No. 5 can be reduced. In addition, since the locking performance against longitudinal force is improved, the amount of displacement of the upper arm 13, lower arm 14, and assist arm 15 in the rearward direction of the vehicle is reduced, and the posture of the rear wheel 2 can be stabilized, and the amount of prying of each elastic bushing can be reduced. is reduced, and the friction of the suspension 10 is reduced. Furthermore, as the amount of displacement of the upper arm 13 in the longitudinal direction of the vehicle decreases, each of the elastic bushes 23 and 24 of the support mechanism 19 decreases.
can be placed close together.

As a result, it is advantageous in terms of space.

Furthermore, there are two mounting parts 21 on the front side of the subframe 18.
By making the upper arm 13 attached by the rear attachment part 22 into an arm shape, there is more space between the upper chambers of the suspension lO than with an A-arm shaped upper arm which is also attached to the vehicle body at two locations. .

Since the inner end 13c of the upper arm 13 on the vehicle body side is attached via a support mechanism 19 having elastic bushings 23 and 24 disposed in close proximity, the load borne by the upper arm 13, that is, the upper end of the wheel carrier 11 Lateral forces, etc. acting on the elastic bushes 23, 24 are dispersed. Therefore, the rigidity of the support mechanism 19 is improved and the load acting on each elastic bushing 23, 24 is reduced.

Therefore, it is possible to use a soft material for the elastic bushes 23 and 24, and it is possible to improve vibration absorption, and
Even if the rigidity of the trailing arm 12 is improved, the toe-in change of the suspension 10 can be obtained.

In this embodiment, the spring constants of the elastic bushes 23 and 24 disposed on the support mechanism 19 are made the same; however, the present invention is not limited to this.
The spring constant of the elastic bushing 23 of the front mounting part 21 may be smaller than the spring constant of the elastic bushing 24 of the rear mounting part 22. In this case, the spring constant of the elastic bushing 23 of the front mounting part 21 of
is biased toward the rear compared to the wheel-side inner end 13b of the upper arm 13, so the upper arm 13 rotates around the rear mounting portion 22, thereby reducing the amount of toe change when the suspension 10 toes out. become. As a method of reducing the spring constant of the elastic bushing 23, there are a method of using rubber with low hardness for the elastic bushing 23, a method of providing a cavity, a hollow part, a notch, etc. in the elastic bushing 23. Alternatively, as described above, there is a method of press-fitting the elastic bushing 23 into the inner cylinder 20 to allow minute rotation, and as a result, obtaining the same effect as reducing the spring constant of the elastic bushing 23. .

Further, in this embodiment, the outer end 15a of the assist arm 15 on the wheel side is attached to the wheel carrier 11, but the configuration is not limited to this, and the outer end 15a of the assist arm 15 may be attached to the trailing arm 12. 15 improves the degree of freedom in setting the toe angle change.

(Effects of the Invention) As explained above, according to the present invention, a wheel support member rotatably supports a wheel, and the wheel support member extends substantially in the front-rear direction of the vehicle body and is fixed to the rear end, and the front end is connected to the vehicle body; an upper arm that extends in the vehicle width direction and connects the upper part of the wheel support member to the vehicle body; and a front and rear arm that extends in the vehicle width direction and connects the lower part of the wheel support member to the vehicle body. In a rear suspension for a vehicle having two lower arms, the swing arm is configured to have a closed cross-section structure, a bush is provided at a connecting portion of at least one of the two lower arms, and the inner ends of the upper arms are arranged close to each other. Since the suspension is connected to the vehicle body through two bushings extending in the longitudinal direction of the vehicle body, the rigidity of the suspension and the durability of the elastic bushings are greatly improved. Further, the amount of twisting and load on the elastic bushing is reduced, and furthermore, the vibration of the suspension transmitted to the vehicle body can be reduced. Therefore, there are excellent effects such as improved vehicle handling and ride comfort.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of a rear suspension for a vehicle according to the present invention, Fig. 2 is a rear view of Fig. 1, and Fig. 3 is a partially cutaway enlarged view of the part indicated by the circle ■ in Fig. 1. FIG. 4 is a perspective view of a conventional suspension pencil. 1... Rear wheel, 10... Rear suspension, 11.
...Wheel carrier, 12...Trailing arm, 13...Upper arm, 14...Lower arm, 1
5... Assist arm, 19... Support mechanism, 23.
24...Elastic bushing. Applicant Mitsubishi Motors Corporation

Claims (1)

[Claims] a wheel support member rotatably supporting a wheel; the wheel support member extending substantially in the front-rear direction of the vehicle body and fixed to a rear end;
a swing arm whose front end is connected to the vehicle body; an upper arm which extends in the vehicle width direction and connects the upper part of the wheel support member to the vehicle body; and an upper arm which extends in the vehicle width direction and connects the lower part of the wheel support member to the vehicle body. In a rear suspension for a vehicle equipped with two front and rear lower arms, the swing arm has a closed cross-section structure, a bush is provided at a connecting portion of at least one of the two lower arms, and the inner ends of the upper arms are connected to each other. A rear suspension for a vehicle, characterized in that the rear suspension is connected to a vehicle body via two bushes that are close to each other and extend along the longitudinal direction of the vehicle body.