JPS6348837Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic shock absorber for a vehicle that adjusts damping force and vehicle height.

2. Description of the Related Art Hydraulic shock absorbers used in vehicles are known that allow adjustment of vehicle height. They respond to so-called static changes in load by adjusting the gas pressure to increase or decrease the gas repulsion force and increase or decrease the suspension force to make the vehicle higher or lower in response to changes in the number of passengers or payload. It is something. Therefore, the above-mentioned hydraulic shock absorber, which increases gas pressure and uses the gas reaction force as a compression side reaction force (damping force) against the intrusion of the piston rod, prevents the so-called rolling and longitudinal movements (nose dive and squat) of the vehicle. It has poor responsiveness and is unsuitable for responding to dynamic changes in load.

On the other hand, a hydraulic shock absorber is known in which the damping force is variable so as to suppress the dynamic changes of the vehicle, and the resistance (damping force) is used to resist the intrusion movement of the piston rod.

However, this type of vehicle cannot resist the movement of the piston rod in response to static load changes such as the number of passengers or the load, and the vehicle height gradually decreases.

The present invention is intended to solve the above-mentioned problems, and is equipped with means for adjusting damping force and vehicle height, and a control device for operating these, so that it can respond to static and dynamic load changes of the vehicle. The purpose of the present invention is to provide a hydraulic shock absorber with improved riding comfort and running stability. That is, in order to achieve the above object, in the present invention, a piston rod connected to a piston is housed in a cylinder so as to be able to expand and contract, and hydraulic oil is provided to communicate upper and lower oil chambers in the cylinder defined by the piston. A means for adjusting the damping force by configuring the passage in a closed loop shape and regulating the flow rate of hydraulic oil that moves between the upper and lower oil chambers in the closed circuit, and a means for applying a supporting force to the piston rod in the extension direction. a vehicle height adjusting means for controlling the air pressure in an air chamber provided to give the same, a means for detecting the load and driving condition of the vehicle, and a means for automatically operating the damping force and vehicle height adjusting means based on the output signals of these. and a control device for controlling.

Hereinafter, the present invention will be explained based on several embodiments with reference to the drawings.

Fig. 1 shows the present invention applied to a single cylinder type hydraulic shock absorber. 1 is a hydraulic cylinder, 2 is a piston rod, and the hydraulic cylinder 1 is connected to an upper chamber A and a lower chamber by a slidable piston 3. B. 4
is a cover fixed to the piston rod 3, and a rubber tube 5 is stretched between the lower edge of the cover 4 and the upper end of the hydraulic cylinder 1 via rings 6 and 7, and air is injected together with the cover 4. It forms room C. The rubber tube 5 has a U-shaped cross section, and when the cover 4 is raised, the surfaces in contact with the hydraulic cylinder 1 are successively separated from the bottom and can be raised together with the cover 4.

Reference numeral 8 denotes an operating rod rotatably inserted into the center hole 9 of the piston rod 2, and a regulating valve 10 is fixed to the lower end of the operating rod. This regulating valve 10 has a plurality of orifices 1 radially extending from its inner hole.
1 is formed, and the upper chamber A and the lower chamber B are communicated through a port 12 formed in the lower side of the piston rod 2, an orifice 11 of the regulating valve 10, and a central hole 9 of the piston rod 2. in this way,
A closed-loop hydraulic circuit is constructed between the upper and lower oil chambers A and B, and hydraulic oil is not supplied or discharged from the outside.

In this hydraulic shock absorber, the upper end of the piston rod 2 is fixed to a part of the vehicle body 13, and the lower end of the bracket 1 is fixed to a part of the vehicle body 13.
4 is connected to the axle side.

The upper end of the operating rod 8 is connected to the output shaft of a rotary solenoid 15 fixed to the vehicle body, while the air chamber C is connected to the supply/discharge valve 1 fixed to the vehicle body.
6 to a pressure tank 17.

The above rotary solenoid 15 and supply/discharge valve 1
6 are both controlled in operation by signals from a control device 18, and the control device 18 includes a load sensor 1.
9, vehicle speed sensor 20, steering sensor 21,
Detection values from means for detecting driving conditions such as the brake sensor 22, accelerator sensor 23, and road surface sensor 24 are input, and the control device 18 uses these to obtain the optimal vehicle height and damping force at the time. rotary solenoid 1
5 and the supply/discharge valve 16 are operated.

The present invention is constructed as described above, and its operation including its control operation will be explained next.

First, during the pressure side operation in which the piston rod 2 enters the inside of the hydraulic cylinder 1 from the state shown in FIG. 1, the upper chamber A expands as the piston 3 descends.
When the hydraulic oil from the lower chamber B shrinks, the damping valve 4
1, the center hole 9 of the piston rod 2, and the regulating valve 10
through orifice 11 and port 12. At this time, until the damping valve 41 opens, an appropriate damping force is generated due to the resistance given to the hydraulic oil flowing through the orifice 11. This orifice 1
1 by driving the rotary solenoid 15 with a signal from the control device 18 and rotating the regulating valve 10 via the operating rod 8, the damping force changes, that is, the smaller the area of the orifice 11, the more the damping Power increases.

Incidentally, the hydraulic oil corresponding to the volume entered by the piston rod 2 pushes the free piston 40 and compresses the gas chamber D. On the contrary, during the expansion side operation, hydraulic oil from the upper chamber A flows into the lower chamber B through the orifice 11 as well as the damping valve 42, and similarly generates a damping force.

On the other hand, the air in the pressure tank 17 charged by the compressor 25 is supplied to the air chamber C through the supply/discharge valve 16.
When the valve is opened and guided, the volume of the air chamber C increases, the hydraulic cylinder 1 is lowered relative to the piston rod 2, and the vehicle height can be increased. Conversely, if the air in the air chamber C is released to the atmosphere through the supply/exhaust valve 16, the vehicle height will be lowered.

In a vehicle equipped with this hydraulic shock absorber, the control device 18 controls the load sensor 1 when the vehicle is empty and has a light load.
In response to the detection signal 9, an output signal is sent to the supply/exhaust valve 16, the valve 16 is opened to release a part of the air in the air chamber C, and the vehicle height is adjusted to the optimum standard vehicle height.
When the vehicle speed is high, the vehicle height is lowered to maintain high-speed driving stability. On the other hand, when loading a vehicle or driving at low speed, the supply/discharge valve 1 is connected to the pressure tank 17 charged by the compressor 25 to maintain the standard vehicle height.
By opening 6, air is supplied to the air chamber C to raise the vehicle height and prevent the hydraulic shock absorber from bottoming out.

On the other hand, when lateral acceleration or longitudinal acceleration is applied to the vehicle body, such as when the vehicle is cornering, suddenly braking, or suddenly starting, the left and right hydraulic shock absorbers and the front and rear hydraulic shock absorbers receive compression force, causing the piston rod 2 to suddenly move. It enters the inside of the hydraulic cylinder 1, causing rolling of the vehicle body, nose dive, etc.

In such a case, the steering sensor 21, brake sensor 22, or accelerator sensor 23
Upon receiving the detection signal, the control device 18 outputs an output signal to the rotary solenoid 15 to operate it, rotates the regulating valve 10 via the operating rod 8,
The orifice 11 facing 2 is changed to one with a smaller opening area to throttle the hydraulic oil, and the compression side damping force is increased to play the role of anti-roll and anti-nose dive.

Furthermore, when a predetermined high speed is reached or when driving on an uneven, rough road, the control device 18 operates the rotary solenoid 15 in response to detection signals from the vehicle speed sensor 20 and road surface sensor 24 to increase the damping force. to improve driving stability.

Next, Fig. 2 shows an application of the present invention to a separate tank type strut type hydraulic shock absorber, in which the upper chamber A and the lower chamber B are connected by a port 12 formed in the piston rod 2 and a pipe 2A connected to the piston rod 2. The formed double hole outer hole 26, connector 27, piping 28, connector 27, and the double hole inner hole 2
9, and the middle of the pipe 28 is connected to the pipe 30.
Free piston 32 is connected to a separate tank 31 via
The pipes 28A and 28B are connected to the oil chamber E of the air chamber C and oil chamber E defined by the pipes 28A and 28B.
A compression damping valve 33, a first suction valve 35, a rebound damping valve 34, and a second suction valve 36 are interposed, respectively. In order to make the orifices of the compression side damping valve 33 and the rebound side damping valve 34 variable, a first solenoid 37 and a second solenoid 38 are installed, respectively, to supply air between the air chamber C of the tank 31 and the pressure tank 17. A discharge valve 16 is interposed, and these first and second solenoids 37, 38 and the supply/discharge valve 16 are connected to a control device 18 equipped with various sensors as in FIG.

In this hydraulic shock absorber, when operating on the pressure side, hydraulic oil from the shrinking lower chamber B flows into the expanding upper chamber A through the inner hole 29 of the piston rod 2 and the connector 2.
7. It flows through the pipe 28A, the pressure side damping valve 33, the second suction valve 36, the pipe 28B, the connector 27, the outer hole 26 of the piston rod 2, and the port 12, and the surplus flows into the oil chamber E of the tank 31. .

At this time, the compression side damping valve 33 provides resistance to the flowing hydraulic oil and generates an appropriate damping force, but the first solenoid 37 operates and narrows the opening area of the compression side damping valve 33, thereby creating a large pressure side damping force. You can gain strength. Also, the rebound damping force is the same as above,
It is adjusted by the expansion side damping valve 34.

On the other hand, the pressure in the air chamber C of the tank 31 is balanced with the pressure in the lower chamber B under a certain load. When the valve is opened and the pressure is applied, the free piston 32 descends due to the pressure and pushes out the hydraulic oil in the oil chamber E, so the hydraulic oil is guided to the lower chamber B.
Piston rod 2 comes out and the vehicle height becomes higher.
In this way, the control device 18 operates the first and second solenoids 37, 38 and the supply/discharge valve 16 to adjust the damping force on the compression side and the rebound side and the vehicle height in the same manner as in the embodiment shown in FIG. That's what I do.

As explained above, according to the present invention, the hydraulic shock absorber is equipped with means for adjusting the damping force and vehicle height, and these means are operated by a control device having a sensor that detects the driving state of the vehicle. , Automatic control of the vehicle height adjustment means using aerodynamic force to deal with static changes in vehicle load and attitude, and automatic control of means to adjust the damping force of the hydraulic shock absorber in response to dynamic changes in load and attitude of the vehicle. Through the control, each control signal can be promptly received from the control device and automatically responded to, thereby achieving the effect of keeping ride comfort and running stability at an optimum level and improving the overall performance.

[Brief explanation of the drawing]

1 and 2 are side sectional views showing different embodiments of the present invention, respectively. 2... Piston rod, 4... Cover, 5...
Rubber tube, 8...Operating rod, 10...Adjusting valve, 11...Orifice, 12...Port, 1
5... Rotary solenoid, 16... Supply/discharge valve, 18... Control device, 31... Tank, 33...
...Compression side damping valve, 34... Rebound side damping valve, 37... First solenoid, 38... Second solenoid.

Claims (1)

[Scope of utility model registration request] A piston rod connected to a piston is housed in a cylinder so as to be able to expand and contract, and a hydraulic oil passage that communicates the upper and lower oil chambers in the cylinder defined by the piston is configured in a closed loop. means for regulating the damping force by restricting the flow of hydraulic oil moving between the upper and lower oil chambers, and a vehicle for controlling the air pressure in the air chamber provided to provide supporting force in the extension direction to the piston rod. The vehicle is characterized by comprising height adjustment means, means for detecting the load and driving condition of the vehicle, and a control device that automatically controls the operation of the damping force and vehicle height adjustment means based on output signals of these. Hydraulic buffer.