JPH0299415A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To make it possible to perform desired toe control simply and certainly, by dividing a lateral link into two parts and providing a connecting portion for the two parts with elastic bodies, and also specifying the position of the connecting portion. CONSTITUTION:In a driven wherein a rear wheel 3 is vertically moveably supported, via a swing arm type suspension 2, on a subframe 1 fixed on the side of the body of a vehicle, and wherein the suspension 2, prior to extension in a roughly cross direction of the body, has rear lateral links 4, 5 and a hub 6 as a wheel supporting member for axially supporting the rear wheel 3, the rear lateral link 5 is divided into two and formed by a body side link 31 and a wheel side link 32. Body links 31, 32 are connected together by a link connecting portion 33, which is so positioned that during bump-rebounding of the rear wheel 3, moment in the axial direction of the link 5 becomes zero when moment loads are exerted on both ends of the link 5 as elastic bushes 11, 13 each of which is located at one end of the link 5 are elastically deformed about axes.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension device for a vehicle, and particularly to one that performs toe control of wheels depending on driving conditions.

(Prior Art) Conventionally, as a suspension device for a vehicle, one end is connected to a vehicle body and the other end is connected to a wheel support member through an elastic bushing, as disclosed in, for example, Japanese Patent Application Laid-open No. 148707/1983. In a so-called twin-link type vehicle equipped with a pair of front and rear lateral links, the spring characteristics of the elastic bushings are set to be different between the front lateral link and the rear lateral link, thereby reducing the magnitude of the lateral force acting on the wheel. It is known that the wheels, especially the rear wheels, are toe-controlled depending on the weather.

Here, toe control of the rear wheels according to the magnitude of lateral force means, for example, when the lateral force is extremely large, such as when making a sharp turn or changing lanes at high speed, the rear wheels are set in a relative toe-in direction. This increases the grip of the rear wheels and improves steering stability, while at the same time at low to medium speeds and when lateral forces are small, the toe-in tendency of the rear wheels is reduced and turning performance is improved. This includes making things happen. In this case, the characteristic line indicating the amount of change in toe of the rear wheel with respect to lateral force has one bending point (characteristic change point).

(Problem 8 to be solved by the invention) However, in the above-mentioned conventional device, toe control of the wheel is performed simply by adjusting the spring characteristics of the elastic bushings provided at the vehicle body side end or the wheel side end of the front and rear lateral links. However, it is very difficult to adjust the spring characteristics, and it is actually difficult to achieve the desired toe control.

Therefore, in order to solve this problem, the above-mentioned lateral link is divided into two parts, a link on the vehicle body side and a link on the wheel side, and a predetermined amount in the axial direction of both links is attached to the connecting part of the two links. An elastic body is provided that allows relative displacement of the lateral link, and desired toe control according to the magnitude of lateral force can be smoothly and reliably performed from this elastic body and elastic bushings provided at both ends of the lateral link. is possible. However, only the axial load acts on the lateral link 7 (L) (During a bump or rebound of the wheel, when one lateral link swings, the elastic bushings at both ends of the lateral link move around their respective axes.) Torsional deformation occurs, and as a reaction force, a moment load acts on the lateral link from the elastic bushing, but at this time, the divided part of the lateral link (the connection part between the vehicle body side link and the wheel side link) bends and deforms. Therefore, there is a possibility that the function of allowing the relative displacement of the link by the elastic body may be inhibited, making it impossible to perform desired toe control.

The present invention has been made in view of the above-mentioned points, and a particular object thereof is to ensure that the moment loads acting on both ends of the lateral link at the time of bump ψ rebound of the wheel described above are in the same direction. By focusing on the fact that there is a position where the moment becomes zero in the axial direction, and setting the split part of the lateral link at this position,
The purpose is to prevent bending and deformation of the divided portion to ensure desired toe control.

(Means for Solving the Problems) In order to achieve the two-legged objective, the solution of the present invention includes a lateral link whose one end is connected to the vehicle body and the other end is connected to the wheel support member via elastic bushings. In a suspension device for an automobile, the lateral link is divided into two parts, a vehicle body side link and a wheel side link, and a predetermined amount of relative displacement in the axial direction of both links is provided at the connecting portion of the two links. Provide an elastic body that allows this.

Then, when a moment load is applied to both ends of the lateral link due to elastic deformation around the axis of the elastic bushings at each end during a bump/rebound of the wheel, the connecting portion of both links is connected in the axial direction of the lateral link. The structure is such that the moment substantially coincides with the position where the moment becomes zero.

(Function) With the above configuration, in the present invention, even when a moment load is applied to both ends of the lateral link due to the elastic deformation around the axis of the elastic bushings at each end when the wheel bumps and rebounds, the lateral link is Since the connecting portion between the vehicle body side link and the wheel side link of the lateral link is provided at a position where the moment becomes zero, the lateral link does not undergo bending deformation at the connecting portion.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an embodiment of the present invention in which the present invention is applied to a rear wheel suspension device of an FF (front engine ψ front drive) type automobile. Note that the suspension device for the left rear wheel and the suspension device for the right rear wheel have the same configuration, so in the following explanation, the suspension device for the right rear wheel will be explained, and the suspension device for the left rear wheel will not be explained. Omitted.

In FIG. 1, reference numeral 1 denotes a subframe fixed to the vehicle body as a sprung mass, and a rear wheel 3 is held on the subframe 1 via a swing arm type suspension 2 so as to be vertically movable. There is.

The suspension 2 includes a front lateral link 4 and a rear lateral link 5, each extending substantially in the vehicle width direction, and a hub 6 as a wheel support member that rotatably supports the rear wheel 3.

The inner end of the front lateral link 4 is rotatably connected to a support shaft 8 projecting forward from the subframe 1 via an elastic bushing 7, while the outer end is connected to an elastic bushing 9. A support shaft 10 protrudes forward from the hub 6 via
It is rotatably connected to. The inner end of the rear lateral link 5 is rotatably connected to a support shaft 12 that projects rearward from the subframe 1 via an elastic bushing 11, while the outer end is elastic. Bush 1
3, it is rotatably connected to a support shaft 14 that projects rearward from the hub 6. The front lateral link 4 and the rear lateral link 5 are arranged at an angle so as to gradually approach each other toward the outer end in the vehicle width direction so that the hub 6 and the subframe 1 form a trapezoidal link. A spindle 15 is disposed at a longitudinally intermediate portion between the elastic bushes 9 and 13 on the end side, protruding outward from the hub 6, and the rear wheel 3 is rotatably supported around the spindle 15. Thereby, the lateral force input to the rear wheel 3 is approximately equally input to the front lateral link 4 and the rear lateral link 5. In addition, the above-mentioned support shafts 8, 10, 12° 14 and elastic bushings 7, 9, 11
．． The axes of the rear wheels 13 extend in the longitudinal direction of the vehicle body, so that the rear wheels 3 can swing vertically about the support shafts 8 and 12.

The elastic bushings 7.9, 11.13 are fixed to the inner cylinder 16 into which the support shafts 8, 10, 12.14 fit, and to the lateral link 4.5, as shown in FIGS. 2 and 3. It consists of an outer cylinder 17 and a rubber bushing 18 filled between the inner cylinder 16 and the outer cylinder 17. Here, the elastic bushes 9 and 13 at the outer ends of the lateral links 4 and 5 are set to have the same hardness, and the relationship between the load and the amount of deflection in the elastic bushes 9 and 13 is equal to each other. has been done. Further, the elastic bushing 11 at the inner end of the rear lateral link 5
The elastic bushing 9.13 at the outer end is set to have the same hardness, and the elastic bushing 7 at the inner end of the front lateral link 4 is set to be softer than the elastic bushing 11 at the inner end of the rear lateral link 5. ing.

Further, reference numeral 20 denotes a tension rod extending approximately in the longitudinal direction of the vehicle body, and the rear end of the tension rod 20 is rotatable via an elastic bushing 21 with respect to a support shaft 22 protruding inside the hub 6. On the other hand, the front end of the tension rod 20 is rotatably connected to a support shaft 24 provided on the vehicle body side via an elastic bushing 23.

Both elastic bushes 21 and 23 are arranged with their axes extending in the vehicle width direction, and the rear wheel 3 is swingable in the vertical direction about the support shaft 24, and the tension rod 20 This ensures the rigidity of the hub 6 in the longitudinal direction of the vehicle body. The structure of the elastic bushings 21.23 is similar to that of the elastic bushings 7.9, 1 at both ends of the lateral link 4.5 described above.
The structure is the same as 1.13. Further, 25 is a strut whose lower end is connected to the hub 6, and the strut 25
is composed of a shock absorber and a coil spring (not shown).

The rear lateral link 5 is divided into two parts, including a vehicle body side link 31 and a wheel side link 32, and both links 31 and 32 are connected by a link connecting portion 33. The link connecting portion 33 includes the rear lateral link 5
When the rear wheel 3 rebounds, the elastic bushings 11 and 13 at each end of the rear lateral link 5 have elastic bushes 11 and 13 at both ends of the rear lateral link 5. This is the position where the moment becomes zero in the axial direction of the rear lateral link 5 when a moment load is applied due to deformation.

The structure of the link connecting portion 33 is shown in detail in FIGS. 4 and 5. That is, a bowl-shaped holder 34 having a housing portion 34a is welded and fixed to the inner end of the wheel side link 32, and an end 35a of a cylindrical member 35 is caulked to a peripheral edge 34b of the holder 34. It's stopped. An annular elastic body 36 made of rubber or the like is press-fitted or press-fitted into the cylindrical member 35, and the elastic body 36
The outer end portion of the vehicle body side link 31 is fixed (mold adhesive) inside, and the vehicle body side link 31 and the wheel side link 32 are urged in a direction away from each other by the elastic body 36.

An annular regulating member 37 made of a resin molded product such as iron, iron, or urethane is fixed to the accommodating portion 34a of the holding body 34.
The outer end portion of is disposed so as to be movable in the axial direction. That is, an enlarged tip portion 38 is formed at the outer end of the vehicle body side link 31, and the enlarged tip portion 38 is connected to the accommodation portion 37a of the regulating member 37.
The accommodating portion 37a is provided with a space 39 in which the axial pressure #l intersects when the distal end enlarged portion 38 is disposed. In the illustrated state, the biasing force of the elastic body 36 causes the first
The restricting portion 37b abuts 12 the enlarged end portion 38 of the vehicle body side link 31, thereby preventing the wheel side link 32 from moving away from the vehicle body side link 31, that is, toward the wheel. On the other hand, when the wheel-side link 32 moves a distance 9 toward the vehicle body against the biasing force of the elastic body 36, the second restricting portion 37C of the restricting member 37 comes into contact with the enlarged end portion 38 of the vehicle-side link 31. The wheel-side link 32 is configured to be prevented from moving further toward the vehicle body.

The regulating member 37 is divided into two parts, and includes a first regulating body 40 having a first regulating part 37b and a second regulating body 41 having a second regulating part 37e. Also,
Between the holding body 34 and the regulating member 37 and the cylindrical member 35 and the elastic body 36, an annular Zino-4 for adjusting the initial load is provided.
2 is inserted.

Next, to explain the effects of the above embodiment, when a lateral force acts on the rear wheel 3, the elastic body 36 initially counteracts it by its urging force in the link connecting portion 33 of the rear lateral link 5. Then, when the lateral force becomes larger than a predetermined value, the elastic body 36 deforms in accordance with its elastic coefficient, and the wheel-side link 32 moves toward the vehicle body. And elastic body 3
When the wheel-side link 32 moves a predetermined distance after the wheel-side link 6 starts deforming, the second restricting portion 37e of the restricting member 37 comes into contact with the enlarged end portion 38 of the vehicle body-side link 31, and the movement of the wheel-side link 32 is restricted. be done.

Therefore, the deflection characteristics of the elastic bushes 7.11 at the inner ends of the front and rear lateral links 4.5 are different, and the movement of the wheel-side links 32 toward the vehicle body at the link connecting portions 33 and its restriction As shown in FIG. 6, the deflection characteristics of the front lateral link 4 system and the deflection characteristics of the rear lateral link 5 system are different. In FIG. 4, the deflection characteristic of the front lateral link 4 system is shown by the F line, and the deflection characteristic of the rear lateral link 5 system is shown by the R line.

The characteristic line R has two bending points α1. β1, and in the area where the load (lateral force) is smaller than β1, the rate of change in the amount of deflection is small (hard state), and in the area between β1 and α1, the rate of change in the amount of deflection is large (soft state). Furthermore, the rate of change in the deflection of the melon is set to be small (hard state) in the region exceeding α1. Furthermore, the characteristic line F is set to have a road shape. Both characteristic lines R and F intersect at two points γ1 and γ2, and in the region where the load (lateral force) is smaller than γ] and the region larger than γ2, the amount of deflection of the front lateral link 4 system is In a region where the load is between 71 and 72, the deflection amount of the rear lateral link 5 system becomes larger than the deflection amount of the front lateral link 4 system.

Note that the load at the bending point β1 reaches a predetermined value at which the elastic body 36 in the rear lateral link 5 begins to deform. Further, the slope of the characteristic line R from the origin to the bending point β1 and the slope after the bending point α1 depend on the characteristics of the elastic bushes 1.1 and 1.3 at both ends of the rear lateral link 5.

As described above, since the front lateral link 4 system and the rear lateral link 5 system have different deflection characteristics, the toe state of the rear wheel 3 changes depending on the magnitude of the lateral force acting on the rear wheel 3. The relationship between the lateral force and the amount of change of 1·- is shown by the characteristic line X in FIG. β1. γ1
．． γ2 correspond to those in FIG. 4, respectively. Changes in the behavior of the rear wheel 3 based on such characteristic line X are shown in FIG. In Fig. 8, the lateral force is indicated by f, and the attitude change of the rear wheel 3 is indicated by a solid line when the lateral force f is "0";
When the lateral force f is ``small'', it is indicated by a dashed-dotted line, when the lateral force f is ``medium'', it is indicated by a two-dot chain line, and when the lateral force f is ``large'', it is indicated by a broken line. Also, straight lines ml, m2. m3. m4 is the center line in the width direction of the rear wheel 3, ml indicates when the lateral force f is "0", m2 indicates when the lateral force f is "small", and m3 indicates when the lateral force f is "medium core". Further, m4 indicates the case when the lateral force f is "large". In addition, the elastic bushing is 7.9°11.
13 and the link connecting portion 33 are schematically shown in the shape of a spring.

As is clear from Fig. 8, when the lateral force f is "0",
Rear wheel 3 faces straight ahead. When the lateral force f is "small", the amount of deflection of the front lateral link 4 system is greater than the amount of deflection of the rear lateral link 5 system, so the rear wheels 3 are in a toe-in state, ensuring straight-line stability. .

In addition, when the lateral force f is ``mid-center'', the rear lateral link 5
Since the amount of deflection of the system is larger than the amount of deflection of the front lateral link 4 system, the amount of toe-in of the rear wheels 3 is relaxed (reduced) compared to when the lateral force f is "small", which improves maneuverability and maneuverability. Improvements will be made. That is, when the amount of toe-in is reduced, the understeering characteristic is weakened compared to when the amount of toe-in is large, and the direction followability of the vehicle relative to the turning of the steering wheel is improved.

Furthermore, when the lateral force f is "large", the rear wheels 3 are again displaced in the toe-in direction, which strengthens the tendency to understeering when making sharp turns or changing lanes at high speed, ensuring steering stability. be done.

Note that the characteristic line X showing the amount of toe change of the rear wheel 3 with respect to the lateral force f can be changed in various ways depending on the vehicle type, etc., as shown by the broken line in FIG. Each point is indicated by a black dot. The characteristic lines indicated by these broken lines also show the same tendency as the characteristic line X. In other words, the rate of change in the toe-in direction as the lateral force increases (
The change in the toe-out direction (which can be seen as a negative toe-in direction) is smaller in the region between the two bending points than in other regions.

As explained above, according to the suspension device of this embodiment, straight-line stability is ensured when the lateral force is small, turning performance is ensured when the lateral force is moderate, and furthermore, when the lateral force is large, The steering stability can be ensured, and the behavior of the vehicle can be optimized depending on the driving conditions.

Moreover, in order to obtain the above characteristics, a shim 4 of a predetermined thickness is required at the link connecting portion 33 of the rear lateral link 5.
2 and set the initial load appropriately, there is no need to make the deflection characteristics of the elastic bushes 7.9 and 11.13 provided at both ends of the front lateral link 4 and the rear lateral link 5 particularly complicated. do not have. In the embodiment, since the end 35a of the cylindrical member 35 is caulked to the peripheral edge 34b of the holder 34, an initial load of a predetermined thickness is applied to the holder 34 and the regulating member 37 on the vehicle body side. While arranging the adjustment shim 42, the cylindrical member 3
5 is press-fitted to the vehicle body side link 31, and the shim 42 is sandwiched between the cylindrical member 35 and the elastic body 36 and the holding body 34 and the regulating member 37, the end of the cylindrical member 35 is fixed. By assembling the link connecting portion 35 by caulking the portion 35a to the peripheral portion 34b of the holder 34,
The initial load on the link connecting portion 35 can be set accurately and easily. In the case of the embodiment, the initial load adjustment shim 42 is inserted to set the desired initial load at the link joint portion 33 of the rear lateral link 5, but the elastic urging force of the elastic body 36 allows the desired initial load to be set. If the load is available, there is no need to insert the shim 42.

Here, the rear lateral link 5 is not only subjected to an axial force when a lateral force is applied to the rear wheel 3, but also a bending moment is applied when the rear wheel 3 bumps or rebounds.

That is, for example, when the rear wheel 3 bumps, the elastic bushing between the rear lateral link 5 and the subframe 1]
1 is twisted and elastically deformed in the clockwise direction when viewed from the rear of the vehicle around its axis (that is, the support shaft 12), and the elastic bush 13 between the rear lateral link 5 and the hub 6 is also elastically deformed around its axis (that is, the support shaft 12). It is twisted and elastically deformed around the center (that is, the support shaft 14) in a clockwise direction when viewed from the rear of the vehicle body. As shown in FIG. 9, as a deformation reaction force of the elastic bushings 11.13, a bending moment M is generated from the elastic bushings 11.13 to both ends of the rear lateral link 5 in a counterclockwise direction when viewed from the rear of the vehicle body. will act, and the bending moment diagram at this time is shown in FIG.

In response to such a bending moment, in the case of the embodiment, the link connecting portion 33 of the rear lateral link 5 is located at the center in the axial direction of the rear lateral link 5 where the bending moment becomes zero. Bending deformation at the link connecting portion 33 can be prevented. As a result, even when the rear wheel 3 bumps or rebounds, the movement of the two links 31□ 32 toward and away from each other in the link connection portion 33 described above is not hindered, and the rear wheel 3 is reliably controlled. It can be carried out.

In the case of the above embodiment, the elastic bushings 11.13 at both ends of the rear lateral link 5 have the same size and the same hardness, and when the rear wheel 3 bumps and rebounds, the six elastic bushings 11.13.
Since the bending moment acting from 13 on both ends of the rear lateral link 5 is equal, the bending moment becomes zero at the longitudinal center of the rear lateral link 5, and the hardness of the elastic bushes 11 and 13 is different. , when the rear wheel 3 bumps and bounces, the 6 elastic bushings 11.1
When the bending moments acting on both ends of the rear lateral link 5 from the rear lateral link 5 are different, the bending moment becomes zero at a portion other than the axial center portion of the rear lateral link 5. Of course, the present invention can be applied to this case as well.

Further, in the above embodiments, the present invention is applied to a suspension device for rear wheels, but it can also be applied to a suspension device for front wheels. Furthermore, the present invention can be applied to suspension devices of different types from the embodiments. For example, in the embodiment, the front and rear lateral links 4.5 have inner ends wider than the outer ends, and upper arms (rod-shaped or A-shaped) that extend further in the vehicle width direction relative to the hub 6. The present invention can be similarly applied to a so-called double wishbone type (multi-link type) in which two objects (of any shape) are connected.

(Effects of the Invention) As described above, according to the vehicle suspension device of the present invention, moment loads are applied to both ends of the lateral link due to the elastic deformation around the axis of the elastic bushings at each end when the wheel bumps and rebounds. Even when the lateral link is actuated, the connecting portion between the vehicle body side link and the wheel side link of the lateral link is provided at a position where the moment on the lateral link becomes zero, so that bending deformation at the connecting portion of the lateral link is prevented. Therefore, the relative displacement permissive function of the elastic body provided in the connecting portion can be effectively exerted, and toe control of the wheel can be reliably performed.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, in which FIG. 1 is a plan view showing the overall structure of the suspension device, FIG. 2 is a sectional view of an elastic bushing, and FIG. 3 is a sectional view taken along line A-A in FIG. 2. Fig. 4 is a plan view of the rear lateral link, Fig. 5 is a vertical cross-sectional side view of the link connection part of the rear lateral link, Fig. 6 is a characteristic diagram showing the deflection characteristics of the front lateral link and the rear lateral link, and Fig. 7 is a characteristic diagram showing the deflection characteristics of the front lateral link and the rear lateral link. FIG. 8 is a characteristic diagram showing the relationship between lateral force and toe change amount, FIG. 8 is a schematic diagram showing changes in rear wheel behavior, and FIG. 9 is a diagram showing the load state of bending moment acting on the rear lateral link. 4...Front lateral link, 5...Rear lateral link, 6...Hub (wheel support member), 7, 9, 1
1.13...Elastic bushing, 31...Vehicle side link, 32...Wheel side link, 33...Link connection part,
36...Elastic body. L, A Figure 2 Figure 7

Claims (1)

[Claims] (1) In a suspension system for an automobile that includes a lateral link that is connected to the vehicle body at one end and the wheel support member at the other end via an elastic bush, the lateral link is divided into two parts and is connected to the vehicle body side link. The connecting portion of both links is provided with an elastic body that allows a predetermined amount of relative displacement in the axial direction of both links. When a moment load is applied to both ends of the lateral link due to the elastic deformation around the axis of the elastic bush at each end, the moment is set to approximately correspond to the position where the moment becomes zero in the axial direction of the lateral link. A vehicle suspension device characterized by: