JPH0565011A - Suspension device - Google Patents

Abstract

PURPOSE:To perform proper control of a damping force according to the running state of a vehicle by controlling the oil pressure of a cylinder such that each of oil pressures inside and outside the cylinder of a shock absorber is detected and a differential pressure at an electromagnetic proportional relief valve is generated according to the detected result. CONSTITUTION:A shock absorber Sa has a through-hole 3a formed in the core part of a piston rod 3 and two ends in a vertical direction respectively opened to the outer periphery of the piston rod 3 and an oil chamber R2 on the piston side. A pressure sensor C3 is caused to front on the upper opening of the through-hole 3a to detect an oil pressure in the oil chamber R2 on the piston side. Meanwhile, a communicating hole 5a communicated with the outside is formed in an outer cylinder 5 in which a reservoir chamber R3 is formed, and a pressure sensor C4 is caused to front on the external opening of the communicating hole 5a to detect an oil pressure in the reservoir chamber R3. Based on detecting signals from the two pressure sensors C3 and C4, an electromagnetic proportional relief valve Ve is controlled. This constitution generates a differential pressure between the upper and lower parts of the electromagnetic relief valve Ve so as to control the oil pressure of the cylinder 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a suspension device which is most suitable for use in a semi-active suspension or the like as a vehicle suspension system.

[0002]

2. Description of the Related Art Conventionally, there have been various proposals for a suspension device used for a semi-active suspension or the like as a suspension system of a vehicle. For example, in the suspension device shown in FIG. A suspension spring Cs is arranged between the axle A and the vehicle body B in each portion (only one wheel portion is shown in the drawing), and a damping force is provided under the interposition of upper and lower rubber bushes Rs so as to be in parallel with the suspension spring Cs. It is said that an adjustable shock absorber Sa is provided and the damping force of the shock absorber Sa can be controlled to control the riding comfort of the vehicle.

That is, as shown in FIG. 4, the shock absorber Sa is arranged outside the cylinder 1 with the working oil from the expansion side oil chamber R1 defined by the piston 2 in the cylinder 1 when the shock absorber Sa expands and contracts. The electromagnetic proportional relief valve Ve is introduced into the pressure side oil chamber R2 defined by the piston 2 in the cylinder 1 so as to communicate with the reservoir chamber R3 via the electromagnetic proportional relief valve Ve. The damping force of the shock absorber Sa is controlled by controlling the flow passage resistance when the hydraulic oil passes.

Incidentally, in the shock absorber Sa, the upper end side of the piston rod 3 whose upper end is connected to the vehicle body B side and which connects the piston 2 to the lower end is protruded from the upper end side of the cylinder 1 under the shaft sealing structure by the bearing member 4. It is formed into a multi-cylinder type in which the outer cylinder 5 is freely protruded, the outer cylinder 5 is disposed outside the cylinder 1, and the reservoir chamber R3 is formed between the outer cylinder 5 and the cylinder 1, and the pipe 6 is formed on the outer periphery of the cylinder 1. The pipes 6 are connected to each other and have a cylindrical oil passage L1 between the pipe 6 and the cylinder 1.

The cylindrical oil passage L1 communicates with the rod-side oil chamber R1 through the communication hole 1a opened on the upper end side of the cylinder 1 on the one hand, and on the other hand, the electromagnetic proportional connection with the pipe 3 is established. It is set so as to communicate with the relief valve Ve.

The hydraulic oil from the electromagnetic proportional relief valve Ve is set so as to flow into the reservoir chamber R3, and the piston 2 is provided with a check valve 2a to operate from the piston side oil chamber R2. It is set to allow oil to flow into the rod-side oil chamber R1.

The shock absorber Sa closes the lower end of the cylinder 1 with the base valve portion 7, and
It is formed so that the bottom end of the outer cylinder 5 is closed by a bottom member 8. The base valve portion 7 has a communication hole 7a and a check valve 7b, and the hydraulic oil from the reservoir chamber R3 is transferred to the piston side oil chamber R2. Is allowed to flow.

An eye 8a is connected to the lower end of the bottom member 8 so that the lower end of the shock absorber Sa can be connected to the axle A through the eye 8a.

On the other hand, the electromagnetic proportional relief valve Ve has a housing 10 connected to the pipe 6 and the outer cylinder 5,
A casing 11 connected to the housing 10; and the cylindrical oil passage L1 opened in the housing 10.
The front end of the poppet 12 is opposed to the open end of the inflow port 10a communicating with the plunger 14, and the rear end of the poppet 12 is slidably arranged at the center of the solenoid 13 housed in the casing 11. The back side of the tip of the poppet 12 is communicated with the outflow port 10b which is continuously provided and is opened in the housing 10 and communicates with the reservoir chamber R3.

The electromagnetic proportional relief valve Ve is controlled by the supply signal to the solenoid 13 to control the poppet 12.
Is selected, the pressure of the hydraulic oil flowing into the electromagnetic proportional relief valve Ve via the inflow port 10a is controlled, and the damping force of the shock absorber Sa is controlled.

By the way, the suspension device having the shock absorber Sa configured as described above is
As shown in FIG. 3, a vehicle height sensor C1 is provided between the axle A and the vehicle body B, and an acceleration sensor C2 is provided on the vehicle body B. Signals from the sensors C1 and C2 are sent to the controller C, respectively. It is supposed to be entered.

On the other hand, the controller C is a vehicle height sensor C1.
A differentiator 20 for differentiating a detection value from, an integrator 21 for integrating a detection value from the acceleration sensor C2, a controller 22 for inputting each output signal from the differentiator 20 and the integrator 21, An amplifier 23 for amplifying an output signal from the control unit 22 is provided, and the control unit 22 controls the output signal according to the combination of the signs of the differentiator output and the integrator output. Absorber S
It is set so as to be input to the electromagnetic proportional relief valve Ve in a.

In FIG. 3, T represents a tire.

Therefore, according to the above-described conventional suspension device, the state of the vibration induced on the vehicle body B while traveling on the road surface is detected by the vehicle height sensor C1 and the acceleration sensor C2, and the respective sensors C1, C2 detect the vibration. Detection signals are input to the controller C and are output to the electromagnetic proportional relief valve Ve in the shock absorber Sa as a signal processed based on the preset value in the controller C, and the shock absorber Sa is attenuated. It becomes possible to control the force.

As a result, the ride comfort of the vehicle can be improved by controlling the damping force of each part of the four wheels of the vehicle according to the condition of the road on which the vehicle travels.

[0016]

However, in the above-described suspension device having the conventional structure, there is a disadvantage that it is not always possible to realize appropriate control according to the situation of the road surface on which the vehicle is traveling.

That is, in the above conventional suspension device, the controller C controls the damping force by the combination of the sign of the absolute speed of the vehicle body B and the sign of the expansion / contraction speed of the shock absorber Sa so that the controller C detects the detected value from the acceleration sensor C2. And the detection value from the vehicle height sensor C1 is differentiated.

On the other hand, in this type of suspension device, when the shock absorber Sa is arranged between the axle A and the vehicle body B, rubber bushes Rs acting as a kind of spring are provided at the upper and lower ends of the shock absorber Sa. As a general rule, intervene.

The rubber bush Rs is set so as to effectively control the vibration in the low frequency range when the vibration frequency in the shock absorber Sa is in the low frequency range.

Therefore, in the above-mentioned conventional suspension device, when the vibration frequency of the shock absorber Sa having the rubber bush Rs at a predetermined position is shifted to the high frequency range, the rubber bush Rs intervenes, and A phase is generated between the differential value of the detection value from the vehicle height sensor C1, that is, the absolute speed of the vehicle body B, and the integrated value of the detection value from the acceleration sensor C2, that is, the relative speed of the shock absorber Sa, and a predetermined value is obtained. The vibration damping effect of can not be expected.

Therefore, the detected value from the vehicle height sensor C1 facing the detected value from the acceleration sensor C2 provided on the vehicle body B, that is, the vehicle body B as well as the shock absorber Sa described above.
The detection value from the vehicle height sensor C1 disposed between the vehicle and the axle A is conditionally different when the vibration frequency in the shock absorber Sa is in the low frequency region and in the high frequency region. Become.

As a result, in the above-described conventional suspension device, it is not always possible to realize appropriate control according to the condition of the vibration frequency of the shock absorber Sa, that is, the condition of the vehicle on the road.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to realize appropriate control according to the condition of the vehicle while traveling on the road surface, and to suspend the vehicle suspension system. It is an object of the present invention to provide a suspension device that is optimal for use in a barrel active suspension.

[0024]

In order to achieve the above-mentioned object, the structure of the present invention has a structure in which a piston sliding in a cylinder defines a rod-side oil chamber and a piston-side oil chamber, and An electromagnetic proportional relief valve, which forms a reservoir chamber with the outer cylinder that is externally arranged, while operating oil from the rod-side oil chamber when the piston slides in the cylinder It is configured to flow into a reservoir chamber communicating with the piston-side oil chamber via a solenoid valve and to generate a predetermined differential pressure when the hydraulic oil passes through the electromagnetic proportional relief valve to control the damping force. A signal which has a shock absorber disposed between the axle of each part of the wheel and the vehicle body, and which receives a detection signal from an acceleration sensor disposed on the vehicle body and which is processed based on a preset standard. In a suspension device that has a controller that outputs to an electromagnetic proportional relief valve and controls the electromagnetic proportional relief valve according to the condition of the vehicle running road surface, in a shock absorber, a pressure sensor and a reservoir that detect the oil pressure in the piston side oil chamber A pressure sensor for detecting the hydraulic pressure in the chamber is provided, and the detection signals from the pressure sensors are input to the controller together with the detection signals from the acceleration sensor provided on the vehicle body, and
The controller is configured to perform processing based on a preset reference in the controller and output it as a predetermined signal to the electromagnetic proportional relief valve.

[0025]

Therefore, when the shock absorber expands and contracts due to the vibration of the vehicle traveling on the road surface, the piston slides in the cylinder and the working oil from the cylinder is transferred to the reservoir chamber side via the electromagnetic proportional relief valve. It will flow in.

At that time, in the shock absorber,
The hydraulic pressure in the cylinder and the hydraulic pressure in the reservoir chamber are respectively detected by the pressure sensors, and the detection signals from the respective pressure sensors are input to the controller together with the detection signals from the acceleration sensor provided on the vehicle body.

When the shock absorber is extended,
The pressure in the rod-side oil chamber becomes higher than the pressure in the reservoir chamber due to the provision of the electromagnetic proportional relief valve, but the pressure in the piston-side oil chamber becomes lower than the pressure in the reservoir chamber.

Therefore, if the oil pressure in the piston side oil chamber detected by each sensor is set to P3 and the oil pressure in the reservoir chamber is set to P4, P3-P4 will be set during the extension stroke.
<0.

On the contrary, during the pressure stroke of the shock absorber, the rod-side oil chamber and the piston-side oil chamber have the same pressure, and due to the provision of the electromagnetic proportional relief valve, the pressure becomes higher than the pressure in the reservoir chamber. Sometimes P3-P4>
It becomes 0.

On the other hand, in the controller, a value obtained by subtracting the pressure in the reservoir chamber from the pressure in the piston-side oil chamber, that is, P
A combination of 3-P4 and the sign of the output obtained by integrating the detection signal from the acceleration sensor produces a predetermined signal and outputs it to the electromagnetic proportional relief valve.

In the electromagnetic proportional relief valve, a predetermined operation is performed based on a signal input from the controller to generate a differential pressure between the upstream side and the downstream side of the electromagnetic proportional relief valve, and the hydraulic pressure in the cylinder is increased. To control.

As a result, the damping force in the shock absorbers provided in each part of the vehicle is controlled according to the condition of the road surface on which the vehicle is traveling, and the damping force in each part of the vehicle is controlled to be high or low. Enables precise control of comfort.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a suspension device according to an embodiment of the present invention is a suspension device according to the conventional example (see FIG. 3 and FIG. 4),
The basic configuration is the same except that the configuration of the controller C and the configuration of the shock absorber Sa are slightly different.

Therefore, in the following description, different parts in the present invention will be mainly described, and the same parts in the configuration will be denoted by the same reference numerals in the drawings and the description thereof will be omitted.

That is, in the present invention, as shown in FIG. 2, the shock absorber Sa has a through hole 3a in the axial center of the piston rod 3, and the through hole 3a is on the one hand the piston side oil chamber R2. On the other hand, on the other hand, the piston rod 3 is bent in the radial direction in the vicinity of the upper end of the piston rod 3 and opens to the outer periphery of the piston rod 3.

Then, the opening on the upper end side of the through hole 3a, that is,
A pressure sensor C3 is provided adjacent to the opening of the piston rod 3 in the vicinity of the upper end of the piston rod 3 so as to close the piston rod 3. The pressure sensor C3 allows the oil pressure in the through hole 3a, that is,
It is set so that the oil pressure in the piston side oil chamber R2 can be detected.

On the other hand, the outer cylinder 5 forming the reservoir chamber R3 is formed with a communication hole 5a with the outside, and the pressure sensor C4 is provided at the outside opening of the communication hole 5a so as to close it. Are adjacent to each other and are set so that the pressure sensor C4 can detect the hydraulic pressure in the reservoir chamber R3.

That is, according to the present invention, in the shock absorber Sa, in the cylinder 1 which is the piston side oil chamber R2 on the upstream side of the electromagnetic proportional relief valve Ve and on the downstream side of the electromagnetic proportional relief valve Ve. It is set so that the hydraulic pressures outside the cylinder 1 which is R3 can be detected respectively.

Then, as shown in FIG. 2, the detection values of the pressure sensors C3 and C4 are input to the controller C together with the detection values from the acceleration sensor C2 arranged on the vehicle body B.

Further, the controller C uses the above-mentioned sensors C
The signals input from C2, C3 and C4 are processed based on a preset reference, and a predetermined signal is output to the electromagnetic proportional relief valve Ve.

The electromagnetic proportional relief valve Ve performs a predetermined operation on the basis of a signal input from the controller C to upstream side of the electromagnetic proportional relief valve Ve, that is, in the cylinder 1 and the electromagnetic proportional relief valve Ve. On the downstream side,
That is, a pressure difference is generated between the reservoir chamber R3 and the reservoir chamber R3 to control the hydraulic pressure in the cylinder 1.

Therefore, it becomes possible to control the damping force of each shock absorber Sa arranged in each part of the four wheels of the vehicle according to the condition of the road surface on which the vehicle travels, and as a result, the four wheels of the vehicle. It becomes possible to control the ride comfort of the vehicle by controlling the damping force in each part.

[0043]

As described above, according to the present invention, in order to control the damping force of the shock absorber according to the condition of the road surface on which the vehicle is traveling, the condition of the vehicle body is detected by the acceleration sensor provided in the vehicle body. On the other hand, the hydraulic pressure inside the cylinder and the hydraulic pressure outside the cylinder in the shock absorber are detected, and these detection signals are input to the controller, and a predetermined differential pressure is generated in the cylinder by the command signal from the controller. Since the electromagnetic proportional relief valve that controls the damping force of the shock absorber is caused to execute a predetermined control, the action of the rubber bushes arranged at the upper and lower ends of the shock absorber depends on the vibration frequency range of the shock absorber. Even if there is a phase difference between the relative speed of the shock absorber and the relative speed between the vehicle body and the axle, Be accurately controlled preferable damping force in the shock absorber in accordance with the vehicle conditions during surface travel allows, as a result, an optimum in order to improve the vehicle ride.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a suspension device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing an embodiment of the shock absorber shown in FIG.

FIG. 3 is a circuit diagram showing a suspension device according to a conventional example.

4 is a vertical cross-sectional view showing the conventional shock absorber shown in FIG.

[Explanation of Codes] 1 cylinder 2 piston 5 outer cylinder A axle B vehicle body C controller C2 acceleration sensor C3, C4 pressure sensor R1 rod side oil chamber R2 piston side oil chamber R3 reservoir chamber Sa shock absorber Ve electromagnetic proportional relief valve

Claims (1)

[Claims] 1. A piston that slides in a cylinder defines a rod-side oil chamber and a piston-side oil chamber, and a reservoir chamber is defined between an outer cylinder provided outside the cylinder. , When the piston slides in the cylinder, the working oil from the rod side oil chamber flows into the reservoir chamber communicating with the piston side oil chamber via the electromagnetic proportional relief valve arranged outside the cylinder, and the electromagnetic proportional The relief valve has a shock absorber which is arranged between the axle and the vehicle body in each part of the four wheels of the vehicle so as to control the damping force by generating a predetermined differential pressure when the hydraulic oil passes through. ,
In addition, the detection signal from the acceleration sensor of the vehicle body is input, and the signal processed based on the preset standard is output to the electromagnetic proportional relief valve, and the electromagnetic proportional relief valve is used for the condition of the vehicle road surface. In a suspension device having a controller for controlling the pressure in the shock absorber, a pressure sensor for detecting the hydraulic pressure in the piston side oil chamber and a pressure sensor for detecting the hydraulic pressure in the reservoir chamber are provided in the shock absorber, and The detection signal from the sensor is input to the controller together with the detection signal from the acceleration sensor provided on the vehicle body, and the controller processes the signal based on a preset reference in the controller to give a predetermined signal to the electromagnetic proportional relief valve. A suspension device characterized by being configured to output as.