JPS5843812A - Suspension apparatus of automobile - Google Patents

Abstract

PURPOSE:To improve the comfortableness for driving and to secure the steering stability, by making the resultant elastic modulus of a pair of resilient bushes for the displacement of a radius rod from the normal position to a forward position larger thun the resultant elastic modulus for the displacement to a rear position. CONSTITUTION:The resilient bushes (A, B) secured to a bracket 2 on the body side for securing the radius rod 1 are costituted such that the resilient bush (A) has a V-shaped groove 10 in the circumferential surface and cone-shaped recesses 11, 12 in the opposite end surfaces, and the resilient bush (B) has a V- shaped groove 13 in the circumferential surface, with them located on a small diameter section 1b of the radius rod 1, sandwiched by end plates 3, 4 and clamped by a nut 5. When the radius rod 1 is displaced to the right (forward), the resilient bush (A) whose elastic modulus has become greater because the V- shaped groove 10 and the cone-shaped recesses 11, 12 have been collapsed is further compressed, and the resultant elastic modulus of the resilient bushes (A, B) is increased, which becomes greater than that in the case when the radius rod 1 is displaced to the left (rearward).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a suspension system for an automobile, and more particularly to a suspension system for an automobile in which improvements are made to the rasters and bushings for elastically fixing a radius rod to the vehicle body.

In automobile suspension systems, whether of the wishbone type or the strut type, a member supporting the wheel, such as a lower arm, extends in the front-rear direction between a bracket on the vehicle body side and supports the wheel. A radius rod (or tension rod) is provided that receives and shares the force applied in the longitudinal direction in the longitudinal direction. This radius rod has one end pivotally supported by a wheel support member, the other end inserted into a through hole provided in a bracket on the vehicle body side, and a pair of elastic bushes compressed at the front and rear of this through hole. is elastically fixed.

Therefore, the force applied to the wheels in the longitudinal direction is absorbed by the elastic bushings through the radius rods, thereby improving the ride comfort of the automobile. However, this elastic bushing does not just have to be soft; if it is too soft, the wheel will wobble and the steering stability will be impaired. In other words, from the standpoint of vibration absorption, a softer material is desirable, and from the viewpoint of maneuverability, a harder material is desirable. Therefore, conventionally, both of these factors have been taken into consideration and an appropriate elastic modulus has been set for this elastic bushing.

However, since riding comfort and handling stability are mutually contradictory requirements, it is currently impossible to fully satisfy both requirements even if the elastic coefficient is selected to a different value.

A detailed analysis of ride comfort revealed that the vibrations that worsen ride comfort are often caused by the force that is applied rearward to the wheels when the wheels run over pebbles or the like on the road. Therefore, if it were possible to reduce the elastic coefficient of the elastic bushings in particular against this rearward external force, and increase the elastic coefficient against forward external forces, this would improve riding comfort but impair steering stability. It is possible to realize a suspension system without any

SUMMARY OF THE INVENTION In response to this demand, it is an object of the present invention to provide a suspension system for an automobile that improves riding comfort while ensuring maneuverability.

The suspension system of the present invention supports the radius rod on a mounting member on the vehicle body side with a pair of elastic bushes,
The composite elastic modulus of the pair of elastic bushings for forward displacement from the normal position of the radius rod (the position of the radius rod when no longitudinal force is applied to the axle) is set to be thicker than the composite elastic modulus for rearward displacement. This is a characteristic feature.

More specifically, of the pair of elastic bushings, the elastic modulus of the elastic bushing on the side compressed by the forward displacement of the radius rod from the normal position is rapidly increased when the radius rod is displaced forward from the normal position. It is characterized by the fact that

By configuring the elastic bushings in this way, a large elastic coefficient acts against the forward force applied to the wheels, ensuring steering stability.On the other hand, the backward forces applied to the wheels (ride comfort) force affecting 4Q) has a small elastic modulus 4
It can be used to improve riding comfort.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an example of a Witschborn suspension system, which is one object of the renal suspension system of the present invention. In the Wishbone type suspension system, an upper arm 21 and a lower arm 2 are attached to the vehicle body with sleeve lengths at one end 21a and 22a.
A gun 24 for supporting a wheel is provided on a knuckle arm 23 which is supported by shafts 21b and 22b at the swinging ends of the wheels 2, and the knuckle arm 23 is operated by a tie rod 25 to wrap around the steering wheel. The arm 22 is supported on the vehicle body side bracket 2 by a radius rod (tension rod) 1, and the radius rod 1 is elastically fixed to the bracket 2 by a pair of elastic bushes A and B. In the case of the front wheels, even with a strut-type suspension system, the lower arm is supported in the front-rear direction by the vehicle body via two wheels and asrods.

The force applied to the wheel in the vertical direction is absorbed by the damper 26.

1 The composite elastic modulus of the pair of elastic bushes A and H that fixes the radius rod 1 to the vehicle body side bracket 2 is:
As shown by C in the graph of Fig. 2, the radius rod 1 has a large elastic coefficient Kl (inclination) for forward displacement, and a small elastic coefficient 2 for backward displacement. . Therefore, when a forward force is applied to the radius rod 1, the elastic bushes A and B act hard, and when a rearward force is applied, they act softly.・Graph 1 in Figure 2: As is clear, in order for the composite elastic modulus K of a pair of elastic bushes A and B to change as shown by bend C, the elastic bushes A and B must be It is not enough to simply differ the elastic modulus of (A
) of the bushing at the normal position KQ (the position where no external force is applied to the radius rod 1, the horizontal axis is 0 in the graph)
It is necessary to make the value at the forward displacement significantly larger than 1 and the value at the rearward displacement from the position .

In addition, even in the case of rearward displacement, when the magnitude of displacement increases to a certain extent (dl), it is desirable to increase the elastic coefficient somewhat as shown by 2/ from the viewpoint of steering stability.

An example of the structure of a pair of elastic bushes A and B exhibiting a composite elastic modulus K as shown in FIG. 2 is shown in FIGS. 3 and 4. A pair of rotating bodies made of rubber that have a cross-sectional shape as shown in FIG. 3 when no load is applied (a shape obtained by rotating the cross-section in FIG. The elastic bushes A and B are compressed along the radius rod 1 and compressed into the state shown in FIG. 4. In other words, it has a through hole through which the radius rod 1 is inserted along the axis of the cylindrical body when no load is applied, a large ■-shaped groove 1o on the curved surface, and a hole between the axis and the axis on both end surfaces. An elastic frisch A having a shape having coaxial conical recesses 11 and 12;
Similarly, an elastic bushing B having a through hole through which a two-diameter rod is inserted along the axis of the cylindrical body without any load and having a square groove 13 on the curved surface is placed adjacent to both sides of the bracket 2, and the size of the radius rod L is adjusted. A screw thread formed at the tip of the small diameter portion 1b is placed on the small diameter portion 1b formed at the tip of the diameter portion 1-a, and the elastic bushes A and B are sandwiched between the end plates 3 and 4 from both sides. By tightening the nut 5 on the part 1c, the pair of elastic bushes A and B are compressed between the end plates 3 and 4, and the V-shaped groove 10 and the recesses 11 and 12 of the elastic bush A are just formed by the deformation of the elastic bush A. , it is reduced to a state where it disappears. At this time, some of the ■-shaped groove 13 of the other elastic bushing B should remain. In addition, the ■-shaped groove 1 of the elastic bush B
3 is a well-known groove that is provided to improve both ride comfort and handling by deforming to be soft for small displacements and hard for large displacements, but it is not necessary to provide it. It is something.

In this way, the compressed elastic bushes A and B as shown in FIG.
, and since the other bush B has the characteristic of deforming as shown by line B, the composite elastic modulus of both changes greatly from the normal position as shown in graph C. The purpose of the invention can be achieved.

That is, when there is no load, the V-shaped groove 10° recess 11,1
2, the elastic bushing A has these grooves 1o, recesses 1
1, 12, the elastic modulus KA is small, Q, 2
), these grooves 10, concave! 11.12 Since the elastic modulus KA becomes thicker (Kl) after it is crushed and disappears,
If this boundary is made to coincide with the normal position, the deformation will be exactly as shown by KA in FIG. 2. The other elastic bush B has a constant elastic modulus -B while the ~'-shaped groove 13 is present.

If this is combined with elastic bushing A so as to take a normal position within this certain range, a composite elastic bushing like C having characteristic K can be obtained. That is, in FIG. 4, when the radius rod 1 tries to move to the right (forward), it is sufficiently compressed and the ■-shaped groove 10,
Since the elastic bushing A whose elastic coefficient has suddenly increased (K1) due to the crushing of the conical recesses 11 and 12 is about to be further compressed, the elastic coefficient of the entire elastic bushing increases as shown by 1. On the other hand, when the radius rod 1 is displaced to the left (backward) and becomes stiff, the elastic bush B on the right side has a relatively small elastic coefficient KB, so it is compressed and compressed relatively softly, and the entire bush is compressed. The elastic modulus of 1 is small as shown by 2. In this direction, after a certain amount of displacement (d+) occurs, the V-shaped groove 13 is crushed, so the elastic modulus of the elastic bush B becomes thicker (KB'), and the composite elastic modulus also becomes larger (K2'). This is intended to improve maneuverability.

As described above, the suspension system of the present invention greatly changes the composite elastic modulus of the pair of elastic bushes A and H from the normal position, and gently absorbs vibrations to compensate for rearward displacement of the radius rod. The design improves comfort and maintains high handling stability by absorbing vibrations hard against forward displacement, making it possible to satisfy both a good riding comfort and high handling stability. Moreover, all that is required to obtain this effect is an elastic bushing with a special shape, and there is nothing added to the structure of the conventional suspension system.
The intended purpose can be achieved at a very low cost, and the practical benefits are enormous.

In addition, in the above embodiment, an example of the radius rod extending forward from the wheel support member was illustrated and explained, but it goes without saying that the radius rod may be of a type extending backward from the wheel position. An elastic bushing having a special shape may be used as the elastic bushing on the side far from the support member. In either case, in the arrangement shown in FIGS. 3 and 4, the right side is at the front of the vehicle and the left side is at the rear. .

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view 1 of a wishbone type suspension showing an example of the suspension to which the present invention applies, and Fig. 2 shows the elastic modulus of each of a pair of elastic bushes in the suspension of the present invention, and the composite A graph showing the elastic modulus in relation to the displacement of the radius rod. Fig. 3 is a cross-sectional view showing the shape of the elastic bushing before assembly in one embodiment of the present invention, and Fig. 4 shows the shape of the elastic bushing after assembly. It is a sectional view showing a shape. 1...°radius rod 2...Bracket on the vehicle body side 3.4...End plate A, B...Elastic push 10...■-shaped groove of elastic bushing A 11.12...Set of elastic bushing A End face conical recess 13
...■-shaped groove□ of elastic bush B...:. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1) A radius rod that connects the wheel support member and the vehicle body and receives and shares the longitudinal direction of the can applied to the axle in the longitudinal direction;
a mounting member that is fixed to the vehicle body and has an opening through which the radius rod passes; and a pair of mounting members that are fitted onto the radius rod adjacent to both sides of the mounting member, and that are compressed so that the radius rod can be expanded and contracted in the longitudinal direction. The combined elastic modulus of the pair of elastic bushings for forward displacement from the normal position when no longitudinal force is applied to the axle of the radius rod is greater than the combined elastic coefficient for rearward displacement ( An automobile suspension system characterized by the following: 2) The elastic coefficient of the elastic bushing of the pair of elastic bushings that is compressed by the forward displacement of the radius rod from the normal position, and the radius rod moving forward from the normal position. 2. A suspension system for an automobile according to claim 1, characterized in that the suspension increases rapidly when the displacement occurs. 3) The elastic bushing on the side that is compressed by the forward displacement of the radius rod has a through hole through which the radius rod χ is inserted along the axis of the cylindrical body, a V-shaped groove on the circumferential surface, and a V-shaped groove on both end surfaces. ◇4) A suspension system for an automobile according to claim 2, characterized in that it is made of an elastic body having a conical recess coaxial with the shaft.◇4) The suspension is compressed by the forward displacement of the radius rod. The elastic bushing on the side opposite to the elastic bushing on the side has a through hole through which the radius rod is inserted along the axis of the cylindrical body, and is made of an elastic body having a V-shaped groove on the circumferential surface. An automobile suspension system according to claim 3. 5) The radius rod is connected to the wheel support and the hakama member at the front end and to the vehicle body at the rear end, and the radius rod changes the elastic modulus of the elastic bushing on the wheel support member side from the normal position to the front of the pair of elastic bushings. The automobile suspension system according to claim 1, characterized in that the suspension increases rapidly when the suspension is displaced.