JPH0361108A - Suspension control device of vehicle - Google Patents

Abstract

PURPOSE:To make roll center height variable and improve the turning characteristics of vehicles by installing a restraint releasing means which selectively brings to a state of releasing restraint in accordance with the conditions of turning vehicle, corresponding to No.1 and No.2 lower arms, and installing an up/down position adjusting means on No.2 lower arm. CONSTITUTION:The top of a knuckle 2 pivotally supporting a wheel 1 is supported to a car body 4 through a strut assembly 3 while its bottom is supported to the car body 4 through No.1 and No.2 lower arms 5, 9. A fixing member 6 fixing No.1 lower arm 5 to the car body 4 is connected to the car body 4 through a lock cylinder 8 while the inner end of No.2 lower arm 9 with lock cylinder 10 inserted in its middle part is positioned higher than the inner end of the lower arm 5, and fixed to the car body 4 through a fixing member 17. The fixing member 17 is connected the car body 4 through an up/down position adjusting actuator 19. Control is so made to bring the lock cylinder 8 and the lock cylinder 10 into a state of releasing restraint on detection of turning condition or non-turning condition of a vehicle, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension control device for controlling the roll center height of a vehicle.

(Prior Art) Conventionally, the roll center height of a vehicle has been uniquely determined by suspension settings.

That is, in a general suspension as shown in FIG. The point where the line segment connecting the intersection point P with the center line of the wheel 03 and the ground contact center of the wheel 03 intersects the centerline CT of the vehicle body is defined as the roll center RC when traveling straight.

Incidentally, the roll center is the instantaneous center point for the roll motion of the vehicle, and when considered from the vehicle body, it is also the instantaneous center point for the vertical stroke of the wheels. Here, if we focus on the vertical movement of the wheels when considering the vehicle body as a reference, when the wheels bump, the higher the height of the roll center, the greater the displacement of the wheels outward in the vehicle width direction, which increases the tread. Therefore, the higher the roll center is, the more kL2 (k
is the spring constant of the spring, and L is the tread). This improves the roll stiffness.

In this case, the rebound side will have the opposite characteristics to the above, but
Since most of the roll reaction force of the vehicle is received by the outer turning wheel, the roll stiffness is determined by the characteristics at the time of the above-mentioned bump that occurs on the outer turning wheel.

(Problem to be solved by the invention) Therefore, in order to increase roll rigidity and improve turning performance, it is sufficient to set the roll center high, but if the roll center is set high, There is a problem that the straight running performance of the vehicle deteriorates due to the influence of tread changes.

That is, in order to improve straight running performance, it is preferable that the roll center is low, and the influence of roll center height on straight running performance and turning performance has shown a completely opposite tendency as shown in FIG.

For this reason, in the past, it was necessary to select a roll center height that could achieve both straight-line performance and turning performance to some extent, and there was a problem in that straight-line performance and turning performance could not be efficiently improved.

(Structure of the Invention) The present invention has been devised in view of the above points, and includes a wheel support member that rotatably supports a wheel, and a wheel support member that is provided between the wheel support member and the vehicle body and arranged substantially in the vehicle width direction. First and second arms provided together as an upper arm or lower arm, and a second arm provided corresponding to each arm 12 so as to be able to independently release the restraint on the wheel support member by the first and second arms. first and second restraint release means, a vertical position adjustment actuator provided to be able to adjust the vertical position of the inner end of the second arm, a turning state detecting means for detecting a turning state of the vehicle, and a turning state detecting means for detecting the turning state of the vehicle. control means for controlling the operations of the first and second restraint release means and the vertical position adjustment actuator in accordance with the detection output of the means, and selectively bringing both restraint control means into a restraint release state; The second arm is arranged to define a higher roll center than the first arm, and the control means causes the first restraint release means to be in the restraint release state and rotates when it is detected that the second arm is in the swing state. The vertical position adjustment actuator is operated according to the degree of the state to adjust the vertical position of the inner end of the second arm to be higher the sharper the turn is made, while the second restraint releasing means is restrained when the turning state is not detected. A suspension control device for a vehicle, characterized in that the suspension control device is configured to bring the vehicle into a released state.

(Function) According to the present invention, the first and second arms provided corresponding to each lower arm can independently release the restraint on the wheel support member by the first and second arms provided together as the upper arm or the lower arm. The operation of the restraint release means is selectively controlled by the control means, and the control means brings the first restraint release means into the restraint release state when the vehicle is in a turning state, so that the first arm functions as a suspension arm. As a result, the roll center height of the vehicle becomes higher as defined by the second arm, and the turning performance of the vehicle is improved. In particular, the vertical position of the inner end of the second arm is adjustable by a vertical position adjustment actuator, and the control means operates this vertical position adjustment actuator according to the degree of the turning state, so that the sharper the turning, the more the inside of the second arm is adjusted. Since the vertical position of the end is adjusted high, the sharper the turn, the higher the roll center height is set, and the turning performance of the vehicle is improved appropriately and efficiently.

On the other hand, when the turning state is not detected, the control means sets the second restraint release means to the restraint release state.
The arm loses its function as a suspension arm, and the roll center height of the vehicle is defined by the first arm and becomes lower, improving the straightness of the vehicle.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawing.

As shown in FIG. 1, a wheel 1 is rotatably supported by a knuckle 2, and a strut assembly 3 whose lower end is fixed to the upper part of the knuckle 2 has one end supported by the vehicle body 4. There is. A first lower arm 5 is provided between the lower part of the knuckle 2 and the vehicle body 4 and is arranged in the vehicle width direction, and the outer end of the first lower arm 5 is pivotally attached to the knuckle.

The inner end of the first lower arm 5 is pivotally connected to the vehicle body 4 via a pivot member 6, and this pivot member 6 is slidable in the vehicle width direction by a slide bearing 7. 4, and the pivot joint part paulownia 6
is connected to the vehicle body via the τ1 link cylinder 8.

Similarly to the first lower arm 5, the second lower arm 9 is disposed between the lower part of the knuckle 2 and the vehicle body 4 in the vehicle width direction, and has its outer end pivoted to the knuckle 2. The inner end of the second lower arm 9 is located above the inner end of the first lower arm 5 and is pivotally connected to the vehicle body 4 via a pivot member 17. is supported by the vehicle body 4 so as to be slidable in the vertical direction by a slide bearing 18, and the pivot member 17 is connected to the vehicle body via a vertical position adjustment actuator 9. Therefore, the vertical position of the inner end of the second lower A 9 can be adjusted by the vertical position adjustment actuator 19.

Further, the second lower arm 9 is disposed at an angle of inclination that is greater downward than the first lower arm 5 from the inner end to the outer end, and a lock cylinder is provided in the middle part of the second lower arm 9. 10 are provided.

The r1 cylinders 8 and 10 have a similar structure, and as shown in FIG. 2, a piston 12 is slidably inserted into the cylinder 11, and the members connected to the cylinder 11 and the piston 12 are Relative displacement between the connected members can be regulated or allowed. That is, oil is sealed in the cylinder 11, and two oil chambers partitioned by the piston 12 are communicated with each other by a communication passage 13, and this communication passage 13 is provided with a lock valve 14 made of a solenoid valve. There is. For this reason, the lock valve 14 can switch and control the communication and isolation of the two oil chambers, and when the two oil chambers are in the communication state, the connection between the member connected to the cylinder 1 and the member connected to the piston 12 is controlled. Relative displacement is allowed and the corresponding lower arm loses its function as a suspension arm.

Further, when the lock valve 14 is in the closed state, the relative displacement between the member connected to the cylinder 11 and the member connected to the piston 12 is regulated, and the corresponding lower arm functions as a suspension arm. . Note that the lock cylinders 8 and 10 constitute first and second restraint release means, respectively.

In addition, the vertical position adjustment actuator ■9 is slidably moved into the cylinder 20 by the piston 21, as shown in FIG.
is inserted into the cylinder 2 and partitioned by the piston 21.
The overall length is controlled according to the state of oil pressure introduced into two upper and lower oil chambers formed inside the cylinder. In other words, the state of communication between these two power chambers 11 and the oil pump 22 and reservoir tank 23 is controlled by the operating state of the electromagnetic control valve 24.
4, the entire length of the vertical position adjustment actuator 19, that is, the vertical position of the inner end of the second lower arm 9 is adjusted.

Lock valve 1 provided in lock cylinder 8 and lO
4 and the electromagnetic control valve 2 of the vertical position adjustment actuator 19
4 is controlled by a controller 15. In addition, as shown in Figure 4, the controller ■
5 is a steering wheel o) a steering angle sensor 1 that detects the steering angle;
The operation of the lock cylinders 8, 10 and the vertical position adjustment actuator 19 is controlled according to the detection output of a steering angular velocity sensor 25 that detects the steering angular velocity of the steering wheel 6 and the steering wheel, and the control operation is shown in FIG. . That is, the control shown in FIG. 5 is such that when the steering angle of the steering wheel exceeds a predetermined value, the lock cylinder 10 is placed in a locked state (the lock valve is closed), while the lock cylinder 8 is placed in a free state (the lock valve is opened). state), and controls the operation of the vertical position adjustment actuator 19 by supplying a current according to the steering angular velocity to the electromagnetic control valve 24 (the higher the steering angular velocity, the higher the height of the second lower l). Furthermore, when the steering angle of the handle does not exceed a predetermined value, the lock cylinder 8 is placed in a locked state (the lock valve is cut off), while the lock cylinder 10 is placed in a free state (the lock valve is placed in a communication state). Note that the predetermined value for the steering angle in this case is set to a relatively small value because it determines whether or not the vehicle is in a turning state. Further, the steering angle sensor 16 and the steering angular velocity sensor 25 constitute turning state detection means.

Next, the operation of this embodiment will be explained. The second lower arm 9 has an inner end closer to the vehicle body 4 on three sides than the first lower arm 5.
Since the roll center height is pivoted to the lower arm 5 and is arranged to be tilted downward from the inner end to the outer end to a greater extent than the first lower arm 5, the height of the second roll center is lower than the roll center height defined by the first lower arm 5. The roll center height defined by the lower arm 9 is set high.

When the steering angle of the steering wheel exceeds a predetermined value (when the vehicle is in a turning state), the controller 15 sets the lock cylinder 8 in a free state, while the lock cylinder 1
0 is in the locked state, the first V arm 5 is mounted on the vehicle body side so that the part can slide freely in the vehicle width direction, and the first V]
The lower arm 5 loses its function as a suspension arm, and the second lower arm 9 functions as a suspension arm. Therefore, the roll center height of the vehicle is
is defined by the lower arm 9 and becomes higher, improving the turning performance of the vehicle.

1 In particular, the -L lower position of the inner end of the second lower arm is provided to be adjustable by a vertical position adjustment actuator 19, and the controller 15 operates this vertical position adjustment actuator 19 according to the steering angular velocity. (
The steeper the turn, the higher the vertical position of the inner end of the second lower arm 9 is adjusted, so the sharper the turn, the higher the roll center height is set, and the turning performance of the vehicle is improved appropriately and efficiently.

On the other hand, when the steering angle of the steering wheel does not exceed a predetermined value (when the vehicle is traveling almost straight), the mouth/tsuku cylinder 1
Since the lock cylinder 8 is set in the locked state while the lock cylinder 8 is set in the free state, the second lower arm 9 becomes telescopic and loses the function of closing the suspension arm 1, and the first lower arm 5 functions as a suspension arm. do. Therefore, the height of the roll center of the vehicle is lower than that of the first lower arm 5.
, which improves the straight-line performance of the vehicle.

In this way, according to the embodiment mentioned above, the height of the full center can be controlled depending on whether the vehicle is traveling straight or turning, and in the turning state, the height of the full center can be controlled depending on the steering angular velocity. The roll center height is increased, and the turning performance and straight-ahead performance of the vehicle can be independently and appropriately and efficiently improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments; for example, the first and IJm2 arms may be provided together as the upper arm of a double wishbone type suspension, and various other modifications are possible. It goes without saying that there is.

(Effects of the Invention) As specifically explained above in conjunction with the embodiments, according to the present invention, when the vehicle is in a turning state, the roll center height increases according to the degree of the turning state, and the vehicle is in a straight-ahead state. When the roll center height is lowered, the turning performance and straight running performance of the vehicle are appropriately and efficiently improved.

[Brief Description of the Drawings] Fig. 1 is a schematic configuration diagram showing one embodiment of the present invention, Fig. 2 is a structural diagram of the long cylinders 8 and 10, Fig. 3 is a structural diagram of the vertical position adjustment actuator 19, and Fig. 3 is a structural diagram of the vertical position adjustment actuator 19. 4 is a block diagram of the control system, FIG. 5 is a flow L1 chart diagram showing the control operation of the controller 15, and FIG. 6 is a schematic configuration diagram showing a conventional example.
FIG. 7 is a characteristic diagram showing the influence of roll center height on turning performance and straightness. ■...Wheel, 2...Knuckle, 5...First lower arm 8.10...Lock valve, 9...Second lower arm 15...Controller, 16...Steering angle sensor 19...Vertical position adjustment actuator 59

Claims (1)

[Claims] A wheel support member that rotatably supports a wheel, first and second arms that are provided together as an upper arm or a lower arm that are provided between the wheel support member and the vehicle body and arranged substantially in the vehicle width direction; First and second restraint release means are provided corresponding to each of the arms so as to be able to independently release the restraint on the wheel support member by the second arm, and the vertical position of the inner end of the second arm is controlled. An adjustable vertical position adjustment actuator, a turning state detection means for detecting the turning state of the vehicle, and the first and second restraint release means and the above vertical position according to the detection output of the turning state detection means. control means for controlling the operation of the adjustment actuator and selectively bringing both the restraint control means into a restraint release state, the second arm being arranged to define a roll center higher than the first arm; When the turning state is detected, the control means sets the first restraint release means to the restraint release state, and operates the vertical position adjustment actuator depending on the degree of the turning state, so that the sharper the turn, the more the second arm is moved. A suspension control device for a vehicle, characterized in that the vehicle suspension control device is configured to adjust the vertical position of the inner end to a high level, and to bring the second restraint release means into a restraint release state when a turning state is not detected.