JPS62289408A - Rear suspension for automobile - Google Patents

Abstract

PURPOSE:To attempt improvement of both controllability and riding comfort where oscillating members are adapted to secure a wheel to a car body via elastic members in such a way as to be freely oscillated up and dawn by providing the elastic members while they are revolvingly displaced whereby changing a spring constant in the load input direction depending on a running condition. CONSTITUTION: A front and a rear link 2 and 3 extending in the car width direction are adapted to secure a wheel 1 to the member 5 on a car body side via elastic members in such a way as to be freely oscillated up and down. And the structure is constituted to be such that a spring constant in the load input direction from the links is changed by revolving the elastic members 7, which are provided respectively for the mounting sections of each link 2 and 3 to the member 5 on the car body side, around the oscillating center of the links. Displacement in revolution of said elastic members 7 is effected by an electric motor 9 through a link mechanism 11. And the electric motor 9 is controlled by a controller 20 receiving the output from a car speed sensor 19 in such a way that in case of running at high speed, for example, the spring constant of a front side elastic member 7 is made lower than that of a rear side elastic member 7.

Description

[Detailed description of the invention] 3. Detailed description of the invention Industrial applications The present invention relates to an automobile suspension.

Conventional technology Small wheels are connected via swinging members such as arms or links. The spring characteristics of elastic materials such as Vibration and Noise Reduction 9 What was decided as a compromise between various requests such as improving ride comfort and improving handling stability?
It is through.

In contrast to L, a system has been developed in which the hardness of an elastic member can be variably controlled by introducing hydraulic pressure into a hollow part formed in an elastic member.
It is disclosed in Publication No. 707, Japanese Patent Application Publication No. R¥180-148708, etc.

Problems to be Solved by the Invention However, in the case of a system in which hydraulic pressure is introduced into a hollow part formed in an elastic member such as a rubber bushing as described in L, if a high hydraulic pressure is continued to be maintained in the hollow part of the elastic member, the elastic member will break down. The problem is that not only does the durability of the elastic member decrease and there are other problems such as the oil resistance of the elastic member itself, but it is also extremely difficult to realize a correspondence between hydraulic pressure and the spring characteristics of the elastic member. have.

Means for Solving the Problems The present invention provides an automobile suspension in which a swinging member supporting a wheel is mounted and supported at a plurality of locations on a vehicle body side member via an elastic member so that the swinging member can swing up and down. By rotating an elastic member interposed in at least one of the plurality of mounting support parts to the vehicle body side member around the swing center line of the swinging member, the swinging member can be rotated. The present invention is characterized in that it has a structure in which the spring constant in the load input direction changes, and is provided with an actuator that rotationally displaces the elastic member relative to the swinging member depending on the running conditions.

Effect As described above, the elastic member is controlled by the actuator, for example, when steering at low vehicle speeds, the outer turning wheel has a spring constant that changes toe-out, and when steering at high vehicle speeds, the outer turning wheel has a spring constant that changes toe-in. The spring constant is changed by rotation, or the spring constant is high enough to increase the longitudinal stiffness of the suspension during acceleration and deceleration, and low enough to sufficiently absorb and reduce vibrations transmitted from the road surface such as harshness and road noise during normal driving. The actuator rotationally displaces the elastic member to obtain a spring constant, and the actuator controls the rotational direction and rotational displacement angle of the elastic member so as to obtain the optimal spring constant at that time depending on changes in running conditions.

Example Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show a first embodiment of the present invention. In FIG. 1, l is a wheel, and the tips of front and rear links 2 and 3 are pivoted to the wheel 1. , Links before and after? The base ends 2a and 3a of 3 are attached to a shaft 6 supported by a vehicle body side member 5 such as a cross member via an elastic member 7 as shown in FIG. 2 so as to be able to swing vertically. There is. 4 is the rotation axis of the wheel 1.1.

Further, the tip of a radius rod 8 is attached to the wheel 1, and the base end 81 is attached to a vehicle body side member forward (or rearward) of the wheel through an elastic member so as to swing and rotate. The radius rod 8 is configured to support a load in this direction.

As shown in FIG. 2, the elastic member 7 includes an inner cylinder 71, an outer cylinder 72 concentric with the inner cylinder 71, and a rubber or the like interposed and fixed between the inner cylinder 71 and the outer cylinder 72. For example, a gap 73a may be formed in a part of the elastic ring 73 as shown in FIG. 2(a), or an elastic inner ring 73 may be formed as shown in FIG. 2(a). For example, by embedding an intermediate plate 73b such as a metal plate in a part of the board, the angle can be adjusted such that the bony constant is low in the x-X direction and high in the Y-Y direction orthogonal to the By rotating the elastic member 7 with respect to the link base end while being interposed between the shaft 6 and the link base end, the spring constant is changed by the link. It is possible to variably control the spring constant of the elastic member 7 with respect to the wheel side load inputted by the wheel side load.

Although an electric motor or a hydraulic device may be used as the actuator for rotating the L-thickening member 7, the illustrated embodiment shows an example in which an electric motor 9 is used.

That is, the electric motor 9 is attached to the vehicle body side member 5, and the electric motor 9 is
The elastic member 7 is rotationally displaced with respect to the link base end via l'0, the link mechanism 11, and the like.

FIG. 3 shows a specific example of the attachment portion of the elastic member 7. As shown in FIG.

That is, as shown in FIG. 3, the shaft 6 is rotatably supported by a cylindrical member 12 fixed to the ilj body side member 5 by welding or the like via a bearing 13, and both ends of the shaft 6 are provided with elastic Fitting the inner cylinder 71 of the member 7 by means such as serration fitting,
The base end of the driven arm llc of the link mechanism 11 is fitted to one end of the shaft 6 by means of serration fitting, etc., and the nut 14 is screwed into the threaded portions at both ends of the shaft 6. The elastic member 7, the driven arm llc, etc. are fixed by tightening together.

Of the elastic members 7 assembled and fixed to both ends of the sleeve 6 as described above, a spherical collar 15 is press-fitted into the outer cylinder of the front elastic member 7a, and a retainer 16 is inserted into the outer peripheral surface of the spherical collar 15. The base end 2a of the front link 2 is fitted and assembled so as to be rotatable, and the spherical collar 15 is press-fitted into the outer cylinder of the rear elastic member 7b. The base end portion 3a of the rear link 3 is fitted and assembled so as to be rotatable.

In FIG. 3, reference numeral 17 indicates the driven arm llc of the link mechanism 11 and the connecting rod 1 (having a length adjustment mechanism).
1b, and the other end of the connecting rod ttb is connected to the tip of the driving arm lla fixed to the output shaft of the reducer 10 via the joint, as shown in FIG. combined. 18 is an oil seal.

The electric motor 9 has a sensor for detecting the running state, for example, ii
The rotation direction, rotation angle, etc. are controlled by an output signal from a controller 20 based on a vehicle speed signal from a vehicle speed sensor 19 that detects j speed.

In the above, the left front and rear elastic members 7 are each 7a.
, 7b, and the front and rear elastic members 7 on the right side are respectively 7a'',
7b', and front left and right elastic members 7a, 7a'
For example, as shown in FIG. 4(a), the left and right elastic members 7a and 7a'' on the front side are assembled with the rear left and right elastic members 7b and 7b'' angularly displaced by 90'. The spring constant is high in the axial direction of the link 2 and low in the vertical direction, and the rear left and right elastic members 7b, 7
b" has a low spring constant in the left-right direction (axis direction of the link 3) and a high spring constant in the vertical direction. In this state, the elastic member 7a is caused by the cornering force as a lateral force acting on the wheel 1.1 when turning. , 7a” and 7b, 7
The amount of deflection of b' is larger in the rear elastic members 7b, 7b'' than in the front elastic members 7a, 7a'', so the wheels on the side farther from the center of rotation (hereinafter referred to as outer wheels) are toe-out, and the side closer to the center of rotation is toe-out. The wheels (hereinafter referred to as inner wheels) are in a toe-in state. When turning, the outer wheel changes toe-out and the inner wheel changes toe-in, which means that 1°l of the wheels (rear wheels) are steered in the opposite direction to the steering direction of the steered wheels, which improves turning performance. This is the most desirable characteristic when steering at low speeds, such as when parking in a garage. By maintaining this condition, it is possible to obtain suspension characteristics that emphasize turning performance as described in item 1-1.

When the intermediate vehicle is traveling in a far range, the controller 20 issues an output signal in response to a signal from the vehicle speed sensor 19, and the electric motor 9 rotates to rotate the driving arm lla clockwise in FIG. 1(a). and rotate the left and right shafts 6.6 clockwise through the connecting rod llb and the driven arm 11c.
Rotate 5 degrees. Then, together with the shafts 6, 6, all the elastic members 7 on the front and rear sides are rotated by 45° clockwise with respect to the base ends 2a, 3a of each link 2.3.
As shown in FIG. 4(o), all the elastic members 7a, 7a
”, 7b.

7b'' has an intermediate spring constant in the left-right direction (a spring constant between a low spring constant and a high spring constant), and the front elastic members 7a, 7a are affected by the cornering force during turning.
' and the amount of deflection of the rear elastic members 7b, 7b'' are the same, and neither the outer ring nor the inner ring has a characteristic of toe change, and it is possible to measure the steering tendency 1- during medium speed running.

In the high vehicle speed range, the controller 20 issues an output signal '-) in response to the signal from the vehicle speed sensor 19, causing the electric motor 9 to rotate and rotate the shaft 6 further 4b' clockwise than in the middle vehicle speed range.

Then, as shown in FIG. 4(C), the front elastic members 7a, 7
a' has a low spring constant on the left and right, and the rear elastic members 7b, 7b
' is a state where the spring constant is high on the left and right, and the outer ring changes toe-in and the inner ring changes toe-out due to cornering force during turning. This means that the wheels (rear wheels) 1.1 are steered in the same direction as the steered wheels, so stability during high-speed running can be significantly improved.

The above embodiment shows an example in which both the front elastic member and the rear elastic member are rotated by the electric motor 9 to change the spring constants of all the elastic members so that the manner in which the toy changes due to cornering force can be controlled. However, one of the front elastic member and the rear elastic member, for example, the rear elastic member, has no change in spring constant, and the other, for example, only the front elastic member is rotated by the rotation of the electric motor 9, and has a high spring constant or an intermediate spring constant. , it is also possible to change it so that it has a low bending constant.

In addition, in the embodiment described above, l is used as a sensor for detecting the running state 5B.
An example is shown in which the controller 20 controls the rotation direction and rotation angle of the elastic member 7 according to the vehicle speed using the J speed sensor 19.

In addition to the vehicle speed, one or more of the following factors are added, for example, engine rotation speed, lateral acceleration, yaw rate, steering angle, etc., and the controller 20 uses these elements to obtain the optimal toy change characteristics for the driving state of the elastic member. It can also be configured to determine the rotation angle and issue an output signal to the electric motor 9, and in this way, more detailed control becomes possible.

For example, when turning during acceleration, a front-engine or front-drive vehicle (hereinafter referred to as a FF vehicle) generally tends to have a large turning radius, that is, it tends to understeer. In the case of a FFR vehicle (hereinafter referred to as an FFR vehicle or RR vehicle), on the contrary, the turning radius tends to become smaller, that is, there is a tendency to oversteer. Therefore, the controller 20 calculates the time rate of change in vehicle speed, that is, the acceleration/deceleration, from the vehicle speed signal from the vehicle speed sensor 19, and adds a steering sensor or lateral acceleration sensor to detect the turning state, such as a yaw rate sensor, to detect acceleration above a certain level. When turning in this state, for example, in the case of an FF vehicle, the electric motor 9 is operated to rotationally displace the shaft 6 and the elastic member 7 so that the outer ring is toe-out and the inner ring is toe-in as shown in Fig. 4 (a). In addition, in the case of F R=i or FF vehicle, operate the electric motor 9 to rotationally displace the shaft 6 and the elastic member 7 so that the outer ring is toe-in and the inner ring is toe-out as shown in FIG. 4 (c). Accordingly, the steering characteristic during accelerated turning can be corrected to a neutral characteristic, that is, a characteristic in which the turning radius hardly changes during accelerated turning.

Furthermore, when turning while decelerating, the turning radius tends to become smaller for both FF cars, FR cars, and RR East cars, so when turning while decelerating above a certain level, the outer wheel Electric motor 9 so that the inner ring is toe-in and the inner ring is toe-out.
By operating the shaft 6 and the elastic member 7 to rotationally displace it, the turning radius can be corrected to a characteristic that hardly changes.

5 and 6 show a second embodiment of the present invention, and in this example, the connection support point of the radius rod 8 to the heavy body side member in a dual parallel link type rear suspension similar to that shown in FIG. 1 is shown. An interposed elastic member is rotationally displaced by an actuator.

That is, the base end 81 of the radius rod 8 whose tip end is connected to a member on the side of the wheel 1 is a shaft that is rotatably supported by a bearing 22 on a bracket 21 fixed to a member on the vehicle body side such as a side frame. An elastic member 2 is attached to one end of 23.
It is supported on the surface so as to be rotatable in the downward direction L through the lever 4.

The member 24 has an inner cylinder 241 and an outer cylinder 2, similar to the elastic member 7 of the first embodiment illustrated in FIGS. 2(4) and 2(0).
Elastic ring 2 made of rubber or the like fixedly interposed between 42 and 42
43, or by embedding an intermediate plate made of a metal plate or the like in a part of the elastic ring 243, as shown in FIG. 2 (rl). The spring constant is configured to change depending on the angle, for example, a low spring constant in the xx direction and a high spring constant in the Y-Y direction perpendicular to the xx direction.

The elastic member 24 has its inner cylinder 241 fitted to one end of the shaft 23 by means such as serration fitting, and is assembled and fixed by screwing and tightening a nut 25 to the tip of the shaft 23. The spherical collar 26 is press-fitted into the outer cylinder 242 of the spherical collar 26, and the base end 81 of the radius rod 8 is rotatably fitted and assembled on the outer peripheral surface of the spherical collar 26, and the shaft ? By rotating the elastic member 3, the elastic member 24 is rotationally displaced relative to the radius rod 8.

Reference numeral 27 denotes an electric motor that rotates the shaft 23, and the direction and angle of rotation of the electric motor 27 are controlled by an output signal from a controller 29 based on a vehicle speed signal from a sensor that detects the running state, for example, a vehicle speed sensor 28 that detects vehicle speed. The rotation of the electric motor 27 is transmitted to the shaft 23 through a reduction gear 30, rotation transmission shafts 31, 32, and the like. 33.34 is a universal joint,
25 is an oil seal.

In FIGS. 5 and 6, the same reference numerals as in FIG. 1 represent the same parts.

The radius rod 8 is used to maintain the longitudinal rigidity of the suspension consisting of links 2 and 3, etc., and therefore supports the radius rod 8 to the vehicle body side member during acceleration and deceleration when a large longitudinal load is applied to the suspension. It is necessary to increase the spring constant of the elastic member 24 interposed at the point to prevent excessive toe angle changes of the wheels 1, 1, but this is called reducing vibration transmission from the wheel side members during driving. From this point of view, it is desirable to keep the spring constant of the elastic member 24 low.

Therefore, based on the input of the vehicle speed signal from the vehicle speed sensor 28, the controller 29 detects the acceleration state and deceleration state from the time change rate of the vehicle speed, and when the acceleration and deceleration are equal to or higher than the set values, it issues an output signal and rotates the electric motor 27. By rotating the shaft 23 by a certain rotation angle, the elastic member 24 is angularly displaced so that its Y-Y line substantially coincides with the axis of the radius rod 8. Then, the elastic member 24 receives the load acting in the axial direction of the radius rod 8 due to acceleration/deceleration with a high deflection constant, improving the longitudinal rigidity of the suspension and suppressing excessive toe angle changes. be able to.

During normal running other than when accelerating or decelerating, the electric motor 27 moves the elastic member 24 to its
The radius rod 8 is angularly displaced so that the line almost coincides with the axis of the radius rod and maintained in that state.
The vibration load in the axial direction is absorbed and reduced by the low spring constant part of the elastic member 24, and the vibration of the vehicle body due to harshness and road noise is caused by the vibration of the wheel side of the shade.

Significantly reduce noise and improve ride comfort without making changes i).

In addition to the Qj speed sensor shown in t as a sensor for detecting driving conditions, an engine rotation speed sensor for detecting engine rotation speed is added. The longitudinal stiffness of the suspension that should lower the peak point of vehicle body vibration due to force may be determined, and the elastic member 24 may be angularly displaced to match the stiffness to a spring constant of q1.

In addition, the fifth and sixth embodiments shown in FIGS. 1 to 4 are
The second embodiment shown in the figure may be combined; in this case, the sensors and controller are shared, and the elastic member 24 interposed at the connection support point of the radius rod 8 to the vehicle body side member is the same as that of the first embodiment. The rotation is controlled by the controller so as not to interfere with the toe angle control during steering, or to assist the toe angle control.

L2 1st. In each of the second embodiments, the specific structure of the elastic member and the rotation control structure of the elastic member may be any structure other than the one shown in the drawings within the scope of the purpose of the present invention, and the actuator is not shown in the drawings. Not only an electric motor but also any other actuator such as a hydraulic type or a vacuum type can be used.

Furthermore, the present invention is not limited to the dual parallel link type suspension as shown in the drawings, but also includes other suspensions such as a trailing arm type or a semi-trailing arm type, in which rocking members that support the wheels so as to be able to swing downward in the L direction are installed at multiple locations on the vehicle body side. Needless to say, the present invention is applicable to any type of suspension that is attached to and supported by a member via an elastic member.

Effects of the Invention As described above, the present invention provides an automobile suspension in which a swinging member that supports a wheel in a vertically swingable manner is attached and supported to a vehicle body side member at a plurality of locations via an elastic member. An elastic member interposed at at least one of the attachment support points to the vehicle body side member,
The structure is such that the spring constant in the direction of load input from the swing member changes by rotating the swing member around the swing center line, and the elastic member is rotated relative to the swing member depending on the running conditions. By providing an actuator that rotates and displaces the suspension, the support rigidity of the entire suspension can be adjusted to, for example, vehicle speed, engine rotation speed, etc. with an extremely simple configuration.
It is variably controlled to the most suitable value for the situation depending on vehicle behavior (lateral acceleration, yaw rate, etc.) and driving conditions such as steering, improving maneuverability, high-speed stability, reducing vehicle vibration and noise, and improving ride comfort. It is possible to satisfy all the various demands such as

Further, according to the present invention, since no external force (i.e., load from the swinging member) is directly applied to the rotational displacement means of the elastic member,
Even if there is a failure in the actuator or the rotation transmission mechanism from the actuator to the elastic member and the elastic member cannot be rotated, there is almost no problem with the traveling machine, which is extremely desirable from a safety standpoint. This can bring about great effects in practical use.

[Brief explanation of drawings]

1 to 4 show a first embodiment of the present invention, and FIGS. 1(A) and 1(O) are plan explanatory views and front views, and FIGS. 2(4) and (0) are Front views, Figures 3(A) and 0
) is a cross-sectional plan view and a front view showing a specific structural example of the attachment support part of the link to the vehicle body side member in FIG. 1, and FIG. 4 (4), (a), and (c) are the vehicle body side member of the link. FIG. 6 is a front view showing an example of a rotational restraint 'a' of four elastic members on the front left and right sides and the rear left and right sides interposed in the attachment support part. 5 and 6 show a second embodiment of the present invention, FIG. 5 is a y-plane explanatory view, and FIG. 6 (A)
, (a) is a cross-sectional view showing a specific example of the attachment support part of the radius rod to the heavy body side member in FIG. 5, and an example of an elastic member interposed in the attachment support part of the radius rod to the vehicle body side member. FIG. DESCRIPTION OF SYMBOLS 1... Heavy wheel, 2, 3... Link, 5... Vehicle body side member, 6... Shaft, 7... Elastic member, 8... Radius rod, 9, 27... Electric motor , 19, 28...
Vehicle speed control 1.20.29...Controller, 23...
·sleeve. More L

Claims (1)

[Claims] In an automobile suspension in which a swinging member supporting a wheel is mounted and supported on a vehicle body side member at a plurality of locations via an elastic member so as to be able to swing vertically, the mounting support portion of the swinging member to the vehicle body side member at a plurality of locations is The structure is such that the spring constant in the direction of load input from the swinging member changes by rotating the elastic member interposed in at least one of the mounting support parts around the swinging center line of the swinging member. A suspension for an automobile, further comprising an actuator that rotationally displaces the elastic member relative to the swinging member depending on driving conditions.