JPH048619A - Car stabilizer device - Google Patents

Abstract

PURPOSE:To enhance the comfort in sitting in a car cabin, secure rolling stiffness, and provide controllability for it in accordance with the running condition by equipping a car with a stabilizer device of fluid pressure type, and therein controlling the internal pressure of the stabilizer according to the car running condition. CONSTITUTION:A controller 36 reads sensing signals G from a crosswise acceleration sensor 38 and judges whether or not the reading value ¦G¦ is greater than the reference value G0. In the case of 'No', it is considered to be in a cornering state with a small crosswise acceleration, and piston 30b of a control cylinder 30 is put in the neutral position. In the case of 'Yes', the piston 30b is moved in the direction of boosting the working pressure in compression side cylinder chambers U, L. This constitution prevents worsening of the comfort in car cabin even while running with bounces. Also the car steering characteristics under cornering can be controlled optimally.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a vehicle stabilizer device, and particularly relates to a vehicle stabilizer device using a hydraulic stabilizer such as a hydraulic stabilizer as the stabilizer.

[Conventional technology]

As a conventional vehicle stabilizer device, for example, the one described in Japanese Utility Model Application Laid-Open No. 60-76506 (name of the device is "hydraulic stabilizer") is known.

This conventional device has single-rod, double-acting hydraulic cylinders installed in the vertical direction between the left and right suspension links and the vehicle body, and between the left and right hydraulic cylinders, one upper cylinder chamber and the other The lower cylinder chamber is communicated with the lower cylinder chamber in an intersecting state via hydraulic piping, and orifices are inserted in the middle of each hydraulic piping, and the hydraulic piping portion between each hydraulic cylinder and the upper cylinder chamber ζ orifice is
A spring mechanism that elastically biases the hydraulic oil is communicated.

[Problem to be solved by the invention]

However, in the conventional device described above, the orifices are inserted in the middle of the crossed pipes, and when bouncing,
Because the hydraulic oil passed through the orifice both during rolls, damping force was generated during bounces as well, and when driving on uneven roads accompanied by bounces, the damping force increases, increasing the bumpy feeling and worsening ride comfort. There was a problem.

On the other hand, although it is possible to adjust the spring force of the spring mechanism in advance, the roll stiffness during turning cannot be changed each time according to the magnitude of lateral acceleration. The situation was that it was difficult to apply this method to steering characteristic control.

The present invention has been made in view of the problems and circumstances of the conventional device, and aims to solve the problem without impairing ride comfort even when driving on an uneven road accompanied by bounce, while at the same time preventing roll change. The objective is to ensure a desired roll stiffness and to be able to control the roll stiffness according to the running conditions.

[Means for solving the problem] In order to solve the above problem, the invention described in claim (1)
Double-rod, double-acting type fluid pressure cylinders are installed individually between the left and right suspension links and the vehicle body, and form a pair on the left and right, and between the paired fluid pressure cylinders, one upper cylinder chamber and the other a first conduit interconnecting the lower cylinder chamber; a fluid chamber communicating with each of the first conduits via a second conduit and elastically biasing the working fluid; A stabilizer having a throttle valve inserted in each of the second pipes is provided, an internal pressure variable means capable of changing the internal pressure of the stabilizer, and an operation of the internal pressure variable means is controlled according to the running state of the vehicle. A control means is provided.

Further, in the invention described in claim (2), in the configuration described in claim (1), the internal pressure variable means is provided in a double-rod, double-acting type fluid pressure cylinder, and both cylinder chambers of this fluid pressure cylinder are connected to the first cylinder chamber. and a rod moving mechanism capable of moving the piston rod of the fluid pressure cylinder in the axial direction based on a command from the control means.

[Operation] In each of the inventions of the present application, when the vehicle bounces, one of the upper and lower cylinder chambers of the left and right wheels compresses at the same time, and the other expands at the same time. Therefore, the compressed working fluid in the cylinder chamber enters the extended cylinder chamber of the opposite hydraulic cylinder through the first conduits that cross each other. In this way, the working fluid does not pass through the throttle valve, and the fluid pressure cylinder is double rod-shaped.
Since the volume changes of the upper and lower cylinder chambers are the same, there is no change in the amount of working fluid in the first conduit, and no working fluid flows through the second conduit. In other words, neither the damping force caused by the throttle valve nor the reaction force caused by the fluid chamber is produced, and the ride comfort is not deteriorated by the stabilizer device even on an uneven road.

On the other hand, suppose that when turning, for example, a roll occurs in which the left wheel sinks and the right wheel lifts up. As a result, the stroke of the left wheel side hydraulic cylinder is reduced, and the right wheel side hydraulic cylinder's stroke is extended, and one of the two pairs of cross-connected cylinder chambers is compressed together, and the increase in pressure causes the cylinder chamber to operate. Fluid flows into the fluid chamber and is elastically biased.

Moreover, working fluid flows into each of the extending cylinder chambers from the fluid chamber. Therefore, the throttle valve generates a damping force according to the amount of working fluid that passes through it, and the fluid pressure cylinder on the sinking side of the car body generates a force to resist the sinking, and the fluid pressure cylinder on the side of the car body lifts up. Generates a force that resists. At this time, the control means sends, for example, a command corresponding to the lateral acceleration to the internal pressure variable means, and the internal pressure variable means controls the internal pressure of the roll suppression side cylinder chamber. therefore,
The roll stiffness generated in the left and right hydraulic cylinders is freely controlled by the control means, and vehicle body roll is appropriately suppressed. As a result, by appropriately controlling the share of roll stiffness between the front and rear of the vehicle, it is possible to actively control the steering characteristics that depend on the ratio of the amount of load movement between the left and right wheels.

On the other hand, pressure fluctuations due to irregularities in the roll or transient large vibration input during bounce are absorbed by the fluid chamber, and vehicle body vibration is attenuated by the throttle valve.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 of the accompanying drawings.
This will be explained based on the diagram.

First, in Fig. 1, 2L and 2R are the left wheels of the vehicle.

4 indicates the right wheel, 4 indicates a knuckle as a wheel support member, and 6 indicates the vehicle body. A suspension strut 8 having a built-in shock absorber 8A is attached between the upper end of the knuckle 4 and the vehicle body 6 so as to be able to stroke in the axial direction, and coil springs are installed at the upper and lower positions of the suspension strut 8. Equipped with 10.

Furthermore, a lower arm 12 as a suspension link is attached between the lower end of the knuckle 4 and the vehicle body 6.
This lower arm 12 can swing around a swing axis as the knuckle 4 moves up and down.

Further, the vehicle of this embodiment is equipped with a stabilizer device 14. The stabilizer device 14 includes a hydraulic stabilizer 16 that is individually interposed between the left and right knuckles 4 and the vehicle body 6, and a control section 18 that controls the roll rigidity of the stabilizer 16 when turning.

The stabilizer 16 includes hydraulic cylinders 2OL and 2OR as fluid pressure cylinders, and a throttle valve 22L.

22R and oil chambers 24L and 24R as fluid chambers, and each of these elements is connected to a first hydraulic pipe 26A26B (first
pipe) and second hydraulic pipe 28A.

28B (second conduit).

Each of the hydraulic cylinders 2OL and 2OR includes a cylinder tube 20a and a slidable piston 20b that separates the inside of the cylinder tube 2a into two cylinder chambers U and L.
and a piston rod 20c that is fixedly attached to the piston 20b and extends in the axial direction.The two rods are of a double-acting type, and the sliding portions of each rod are sealed in a liquid-tight state.

In each of the hydraulic cylinders 20L and 2OR having such a structure, one end of the piston rod 20c is attached to the lower arm 12, and the other end is left in a free state, and the cylinder duplex 2, which is an example of one end of the piston rod 20c, is attached to the lower arm 12.
The end portions of the hydraulic cylinders 0a are swingably supported by the vehicle body 6, whereby hydraulic cylinders 2OL2OR are erected on the left and right upper and lower hinges, respectively.

Then, the upper cylinder chamber U of the left wheel side hydraulic cylinder 2OL
is connected to the right wheel side hydraulic cylinder 2 via the first hydraulic pipe 26A.
It is connected to the lower cylinder chamber of 0R, and the lower cylinder chamber of the left wheel hydraulic cylinder 2OL is connected to the upper cylinder chamber U of the right wheel hydraulic cylinder 2OR via the first hydraulic piping 26B. They are cross-connected to each other. Further, second hydraulic pipes 28A, 28B are connected to intermediate positions of the first hydraulic pipes 26A, 26B, respectively. The second hydraulic pipes 28A, 28B include an oil chamber 24L,
24R, and its piping 28A, 2
Throttle valves 22L and 22R are individually interposed in the middle of 8B.

Each of the oil chambers 24L and 24R is connected to a cylinder tube 24a.
The cylinder tube 24 has a piston 24b that is slidable within the cylinder tube 24a, and a spring 24c having a predetermined spring constant that presses the piston 24b.
A cylinder chamber is formed on the opposite side of the spring 24c inside the spring 24c.

This cylinder chamber communicates with the second hydraulic piping 28A (28B). Here, the piston 24b and the spring 24c constitute a biasing mechanism.

On the other hand, the control section 18 includes a control cylinder 30, third hydraulic pipes 32A and 32B as third pipes, an electric motor 34, a controller 36, and a lateral acceleration sensor 38.

Of these, the control cylinder 30 is configured as a double-rod double-acting type like the aforementioned hydraulic cylinders 2OL and 2OR, and has a cylinder tube 30a and the inside of this cylinder tube 30a separated into two cylinder chambers R1 and R2. and a slidable piston 30b, and this piston 30b.
The piston rod 30c is fixed to the piston rod 30c and extends in both axial directions, and each sliding portion is sealed in a liquid-tight manner.

Among these, the cylinder chambers R1 and R2 are connected to the third hydraulic pipe 32A.
, 32B, the first hydraulic line 26A.

26B. In addition, the piston rod 30
One end of c is placed in a free state, and a rack 30d is placed on the other end.
is formed. This rack 30d has an electric motor 3
No. 4 binions 34a are engaged with each other. Here, the electric motor 34° pinion 34a and the rack 30d
constitutes the rod moving mechanism.

Further, in this embodiment, the controller 36 is configured to include a microcomputer and a motor drive circuit, inputs the detection signal G of the lateral acceleration sensor 38, performs the processing shown in FIG. 2 described later, and drives the electric motor 34. It outputs a motor drive signal i. Lateral acceleration sensor 38
is installed at a predetermined position on the vehicle body, and detects a positive or negative lateral acceleration signal G in the form of a voltage signal depending on the direction of the inertial force. In addition,
A rotation angle sensor (not shown) is attached to the electric motor 34, and this sensor signal is supplied to the controller 36.
Provided for motor drive processing.

In the above configuration, the control cylinder 30, the third
The hydraulic pipes 32A, 32B and the electric motor 34 form an internal pressure variable means, and the controller 36 and the lateral acceleration sensor 38 form a control means.

Next, the operation of this embodiment will be explained.

First, the processing shown in FIG. 2 performed by the controller 36 will be explained. The controller 36 reads the detection signal G of the lateral acceleration sensor 38 in step (2) in the figure, and then proceeds to step (2).
to move to. In this step (2), it is determined whether the read value ICI at step (2) is larger than the reference value G0. Standard value G.

is a dark value that determines whether the lateral acceleration is large or not.

Therefore, if the determination in step (2) is "NO", it is assumed that the turning state is low in lateral acceleration, and the process moves to step (2), where the piston 30b of the control cylinder 30 is controlled to the neutral position. This position control is performed by supplying the motor drive signal i until the detection signal of the rotation angle sensor of the electric motor 34 (not shown) matches the neutral command value. On the other hand, if the judgment in step (2) is rYES, it is assumed that the turning state has a large lateral acceleration, and the process moves to step (2). Outputs drive signal i. At this time as well, positioning is performed based on the detection signal of the rotation angle sensor of the electric motor 34. Next step ■
It is determined whether or not the control has ended, and if the control has not ended, the above-mentioned process is repeated.

Next, the overall operation will be explained.

Assuming that the vehicle is traveling straight on a good road at a constant speed, the detection signal G of the lateral acceleration sensor 38 is 0, so although the process shown in FIG. 2 described above is performed, the piston rod 30c of the control cylinder 30 is It is maintained at a predetermined neutral position where the volumes of cylinder chambers R1 and R2 are equal. For this reason, one of the first . The second hydraulic pipes 26A, 28A and the other first hydraulic pipe. The internal pressures of the second hydraulic pipes 26B and 28B are equal to each other. In this running condition, there is no bound rebound in the wheels 2L and 2R, so the left and right hydraulic cylinders 2O
There was no stroke change in L, 2OR, and piping 26A,
No flow of hydraulic oil occurs within 26B, 28A, and 28B.

Therefore, the throttle valves 22L, 22R and the pipes 26A, 26B
, 28A, 28B, no damping force is generated due to the flow path resistance, and predetermined suspension characteristics are maintained.

Assume that while the vehicle is traveling straight, a bounce occurs due to unevenness of the road surface. At this time, since the detection signal G of the lateral acceleration sensor 38 remains zero, the control cylinder 30
is not involved in pressure control within the piping. Therefore, if both the wheels 2L and 2R bounce as they pass through the convex portion and the pistons 20b of the hydraulic cylinders 2OL2OR both try to move upwards in the vehicle body, both the upper cylinder chambers U will be compressed at the same time, and the lower cylinder chambers will also be compressed. Both transition to a negative pressure state at the same time. As a result, the hydraulic oil in the upper cylinder chamber U flows into the lower cylinder chamber of the opposite cylinder through the first hydraulic piping 26A (26B). But 1. Since the volume changes of the upper and lower cylinder chambers U and L are equal due to both rod shapes, the first. Second hydraulic piping 2
There is no change in the amount of oil in 6A, 26B, 28A, and 28B. This also applies when both wheels 2L and 2R rebound by passing through the recess and both lower cylinder chambers are compressed.

In other words, during both bounce and rebound, the second hydraulic pipe 2
Since the amount of oil in 8A and 28B does not change, the hydraulic oil does not pass through the throttle valves 28A and 28B, hardly any damping force is generated, and no spring reaction force is generated. As a result, the damping force of the entire suspension system is approximately equal to that of the shock absorber 8.
A and 8A, and there is no damping force generated by the throttle valves 22L and 22H due to uneven road driving with bounce as in the past, and the vibration input from the road surface is absorbed by the soft damping characteristics. , deterioration of riding comfort is prevented.

Furthermore, suppose that the vehicle shifts from the straight-ahead state described above to a turning state. Assume that this turning is, for example, a right turning, and a roll (see arrow A in FIG. 1) is about to occur in which the left wheel 2L side sinks and the right wheel 2R side lifts up when viewed from the rear of the vehicle. During this turning, the lateral acceleration sensor 38 detects the inertial force and outputs a positive or negative acceleration signal G to the controller 36 according to the turning direction, and the controller 36 performs the processing shown in FIG. Then, the electric motor 34 is rotated in the roll suppression rotation direction (in the present example, clockwise in FIG. 1). As a result, the piston rod 30c
is moved by a predetermined distance in the right end direction a in FIG.

Therefore, the cylinder chamber R1 on the electric motor side of the control cylinder 30 is compressed, and the hydraulic oil inside the cylinder chamber R1 is transferred to the first hydraulic piping 2 via the third hydraulic piping 32'A.
While flowing into the 6A side, the other cylinder chamber R2 becomes in a negative pressure state. Therefore, the internal pressure of the first hydraulic pipe 26A,
That is, the working pressure in the upper cylinder chamber U of the left-wheel hydraulic cylinder 2OL and the lower cylinder chamber of the right-wheel hydraulic cylinder 2OR increases, and the pressure in the cylinder chamber of the oil chamber 24L also gradually increases. On the other hand, hydraulic oil flows from the cylinder chamber of the oil chamber 24R into the first cylinder chamber. It is gradually supplied to the second hydraulic pipe 26B28B, the lower cylinder chamber of the left wheel hydraulic cylinder 20L, and the upper cylinder chamber R of the right wheel hydraulic cylinder 20R.

In other words, in addition to the damping force of each shock absorber 8A, due to the throttling effect according to the amount of hydraulic fluid passing through the throttle valves 22L and 22R, the upper cylinder chamber U of the left wheel hydraulic cylinder 20L has a damping force that resists the sinking of the vehicle body. At the same time, a damping force is generated in the lower cylinder chamber of the right wheel side hydraulic cylinder 2OR to resist the lifting of the vehicle body. This creates a rotational moment that resists the roll in direction A in the figure, and the roll is proactively and proactively suppressed.

This rotational moment is adjusted according to changes in lateral acceleration during the turn, and when the turn is completed, the vehicle is automatically returned to the neutral state corresponding to the aforementioned straight running.

In the case of a left turn, the above-mentioned operations are the same, although the left and right directions are reversed.

Therefore, according to the configuration of this embodiment, by adjusting the motor rotational position when driving the electric motor 34,
The position of the piston 30b of the control cylinder 30 is controlled to be deeper or shallower than the neutral position. The internal pressure of the stabilizer 16 changes according to this depth/shallow control, and the roll rigidity for the same inertial force is varied. In this way, the control cylinder 30 is used to adjust the roll stiffness according to the turning state, so even with a hydraulic stabilizer, the value can be adjusted by increasing the roll stiffness and increasing the amount of left and right load movement. Can be changed freely.

In this way, it is possible to freely change the sharing ratio of roll stiffness, that is, the amount of load movement between the front and rear of the vehicle, and there is an advantage that the sum of cornering forces can be changed between the front and rear of the vehicle to reliably control the steering characteristics.

On the other hand, when passing uneven road surfaces or bouncing while turning,
Assume that a large transient vibration is input to the hydraulic cylinders 2OL and 2OR. As a result, pulse-like pressure fluctuations occur in the upper and lower cylinder chambers UL of the hydraulic cylinders 2OL and 20R, but this pressure fluctuation is caused by the spring 2 of the oil chambers 24L and 24R.
In addition to being absorbed by the expansion and contraction of oil 4c, a high damping force is generated in the throttle valves 22L and 22R in response to the sudden change in oil amount, and a buffering effect can be obtained.

By the way, in this embodiment, the control cylinder 30 is closed due to some reason such as the occurrence of an abnormal state in the suspension.
Even if the internal pressure control by
Cylinder piston 2 by cross connection of 6A and 26B
It is possible to obtain a roll suppression effect according to the movement status of 0b.

Further, in this embodiment, the internal pressure variable means is controlled by the electric motor 34 via the rack and pinion mechanism.
0 is controlled, the configuration is simplified.

Note that the fluid chamber connected to the second hydraulic piping in the present invention is not necessarily limited to the above-described configuration,
For example, as shown in Fig. 3, accumulators 40L and 40R
The configuration shown in FIG. 3 is simple and inexpensive.

Further, the working fluid in the present invention is not limited to using hydraulic oil as described above, and for example, incompressible gas may be used as the working fluid,
In that case, pneumatic cylinders having the same structure as in the above embodiment may be used for the upper and lower springs of the left and right wheels and the control cylinder.

Furthermore, the configuration of the control cylinder that forms part of the internal pressure variable means of the present invention is not necessarily limited to that described above, and may include, for example, a cylinder tube with a fixed partition wall provided approximately in the center, and a cylinder tube with a partition wall liquid-tight. A pair of oil chambers are formed between a rod that penetrates the rod and the partition wall that is slidably attached to both sides of the rod in the axial direction across the partition wall.
The actuator may include a plurality of free pistons and a spring whose one end is engaged with each free piston and whose other end is engaged with a stopper fixed to a rod.

Furthermore, the mounting method of the fluid pressure cylinders provided on the left and right wheels may be opposite to that of the above embodiment, and the cylinder tube may be mounted on the lower arm side and the rod may be mounted on the vehicle body side.

Furthermore, the control means in the present invention may not only control the internal pressure variable means according to the lateral acceleration as described above, but may also control the internal pressure variable means according to the steering angle or steering speed, for example. Further, depending on the vehicle speed, for example, the roll stiffness may be increased as the vehicle speed increases.

〔Effect of the invention〕

As explained above, in each invention of the present application, the upper and lower cylinder chambers of a pair of double-rod, double-acting type fluid pressure cylinders provided on the left and right wheels are cross-connected to each other by a first pipe line, and this pipe line In the middle of each, a stabilizer is provided in which the fluid chambers are communicated through a second pipe line in which a throttle valve is inserted, and the internal pressure of this stabilizer is controlled according to the running condition. This is different from the conventional example even during bounce because the insertion position is outside the cross-connection pipe and the volume changes in the upper and lower cylinder chambers are the same as the stroke of the fluid pressure cylinder changes. In contrast, there is no change in the amount of working fluid passing through the second pipe, so the damping force is not generated by the throttle valve, and even when driving on an uneven road with bounce, for example, the damping force by the stabilizer device is Since it hardly occurs, the riding comfort does not deteriorate. On the other hand, when rolling, the cross-piped stabilizer exerts roll rigidity using fluid pressure, and the roll rigidity can be actively controlled.This not only suppresses roll, but also actively controls the amount of load movement in the left-right direction of the vehicle. Through this control, the steering characteristics of the vehicle, especially during turning, can be optimally controlled. Furthermore, the fluid chamber and the throttle valve can provide a reliable damping effect against large transient vibration input from the road surface.

In particular, in the invention described in claim (2), in addition to the above-mentioned effects, by employing a double rod/double acting cylinder, the structure of the actuator portion of the internal pressure variable means is simplified, and the left and right ratios are the same. It has the advantage of being able to control the rate of pressure.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention, FIG. 2 is a flowchart showing an outline of processing in the controller in FIG. 1, and FIG. 3 is a partial circuit diagram showing another example of the fluid chamber. be. The main symbols in the diagram are 4...knuckle, 6...car body,
12... Lower arm, 14... Stabilizer device,
16... Stabilizer, 2OL, 2OR... Hydraulic cylinder, 22L, 22R... Throttle valve, 24L, 24R
...Oil chamber, 26A, 26B...First hydraulic piping, 2
8A. 28B...Second hydraulic piping, 30...Control cylinder, 32A, 32B...Third hydraulic piping, 34
...Electric motor, 36...Controller, 38...
- Lateral acceleration sensors, 40L, 40R... accumulators.

Claims (2)

[Claims] (1) Double-rod, double-acting fluid pressure cylinders that are individually installed between the left and right suspension links and the vehicle body and that form a pair on the left and right, and one upper cylinder chamber between the paired fluid pressure cylinders. and the other lower cylinder chamber, and a fluid that communicates with each of the first pipes via a second pipe and elastically biases the working fluid. a stabilizer having a chamber and a throttle valve inserted in each of the second pipes, and an internal pressure variable means capable of changing the internal pressure of the stabilizer;
A stabilizer device for a vehicle, comprising: control means for controlling the operation of the internal pressure variable means according to the running condition of the vehicle. (2) The internal pressure variable means includes a double-rod, double-acting type fluid pressure cylinder, a third pipe line that communicates both cylinder chambers of the fluid pressure cylinder with each of the first pipe lines, and a third pipe line that communicates the two cylinder chambers of the hydraulic cylinder with each of the first pipe lines, The stabilizer device for a vehicle according to claim 1, further comprising a rod moving mechanism capable of moving the piston rod of the pressure cylinder in the axial direction based on a command from the control means.