JP2514098Y2 - Hydraulic control device for active suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] <Industrial Application Field> The present invention relates to a hydraulic control device for an active suspension device used in a vehicle such as an automobile.

<Prior Art> In a suspension device for a vehicle such as an automobile, a hydraulic actuator is provided between each wheel and a vehicle body, and the pressure of hydraulic oil supplied to each hydraulic actuator is individually controlled according to the force applied to each wheel. , By changing the relative distance between the wheel and the car body, bounce control, roll control,
A so-called active suspension device is known in which pitch control, vehicle height control and the like are actively performed (see Japanese Patent Laid-Open No. 62-289420).

A cylinder device having a reciprocating linear sliding piston is generally used as a hydraulic actuator for the active suspension device, and the pressure control of the hydraulic oil supplied to the pressure chamber is performed by a hydraulic control device including a pressure control valve. It is supposed to be done. This hydraulic control device includes a supply oil passage for sending out the hydraulic oil from the oil pump, a discharge oil passage for returning the hydraulic oil to the reservoir tank, a supply oil passage for the pressure chamber of the hydraulic actuator, and a discharge oil passage. And a pressure control valve for controlling the connection of the hydraulic pressure actuator, and the hydraulic pressure acting on the pressure chamber of each hydraulic actuator can be individually controlled.

In the hydraulic control device as described above, it is necessary to prevent the pressure in the pressure chamber of the hydraulic actuator from decreasing when the engine is stopped and the vehicle height from decreasing. As a means for that, when the engine is stopped, the supply oil passage is separated from the oil pump by the switching valve, and the supply oil passage and the discharge oil passage for the pressure control valve are connected in communication with each other.
It is known that the hydraulic actuator side is pressure-sealed.

<Problems to be solved by the invention> However, in such a conventional hydraulic control device, since the leak passage of the hydraulic actuator communicates with the reservoir tank, the hydraulic pressure of the pressure chamber is not supplied from the piston seal part of the hydraulic actuator. Leakage is unavoidable, and it was difficult to prevent the vehicle height from decreasing over time.

In view of the inconvenience inherent in the hydraulic control device of the conventional active suspension device, the present invention suppresses the pressure drop in the pressure chamber of the hydraulic actuator for a long period of time in a specific operation mode such as when the engine is stopped. An object of the present invention is to provide a hydraulic control device for an active suspension device improved so as to maintain a stable and stable vehicle height.

[Structure of the Invention] <Means for Solving the Problems> According to the present invention, an object having such a structure is to have a pressure chamber and a back pressure chamber which are partitioned by a piston, and to be supplied to the pressure chamber. Hydraulic actuators provided on each of the plurality of wheels to change the relative distance between the wheels and the vehicle body according to the oil pressure, and hydraulic oil from the oil pump are supplied to each pressure chamber of each hydraulic actuator. Supply oil passage, a discharge oil passage for returning the hydraulic oil from the pressure chamber of each hydraulic actuator to the reservoir tank, and a connection between the supply oil passage and the discharge oil passage provided for each pressure chamber. In the hydraulic control device of the active suspension device, which has a pressure control valve capable of individually controlling the pressure of the hydraulic oil applied to each pressure chamber by controlling the
A return passage that connects the back pressure chamber of each hydraulic actuator to the discharge oil passage is provided, and a switching circuit that can selectively cut off communication between the supply oil passage and the oil pump and between the discharge oil passage and the reservoir tank is provided. When the switching circuit is cut off, the supply oil passages to the hydraulic actuators and the discharge oil passages are connected to each other so as to communicate with each other.

<Operation> According to such a configuration, the switching circuit cuts off the communication between the supply oil passage and the oil pump and the communication between the discharge oil passage and the reservoir tank, and at the time of disconnecting the communication, By communicatively connecting the pressure chambers and the back pressure chambers of the hydraulic actuators provided on the respective wheels to each other, a completely closed loop is formed between the hydraulic actuators of all the wheels. Therefore, when each hydraulic actuator is in a static state, the pressure difference between each pressure chamber and each back pressure chamber is virtually eliminated, and the change in stroke due to oil leakage of the piston seal part of the hydraulic actuator is suppressed. To be done. Further, at this time, since the hydraulic actuators of the respective wheels are in pressure balance with each other, when one hydraulic actuator strokes due to the force applied to the wheels from the road surface, this reaction force is transmitted to the other hydraulic actuator. It is also effective as a fail-safe control because it can acquire the function of all-wheel related suspension.

<Embodiment> Hereinafter, the construction of the present invention will be described in detail with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows an embodiment of a hydraulic control system for an active suspension system according to the present invention. In the figure, each wheel 1 (for example, the left and right wheels in the figure) is supported by upper and lower suspension arms 2 and 3 so as to be vertically movable with respect to a vehicle body 4.

A coil spring 5 and a hydraulic actuator 6 are coaxially provided between the lower suspension arm 3 of each wheel 1 and the vehicle body 4.

The hydraulic actuator 6 is of a cylinder-piston type, and the bottom side of the cylinder 7 is connected to the vehicle body 4 and the top side of the piston 8 is connected to the lower suspension arm 3, and the pressure chamber 9 (upper side of the piston) and the back pressure are connected. The piston 8 linearly slides in the cylinder 7 according to the pressure difference between the chamber 10 (the lower side of the piston), in other words, the pressure of the hydraulic oil supplied to the pressure chamber 9, whereby the wheel 1 and the vehicle body 4 The relative distance to and is changed.

The pressure chamber 9 of the hydraulic actuator 6 is individually connected via an oil passage 11 to an output port 13 of a pressure control valve 12 provided corresponding to each hydraulic actuator 6.

The pressure control valve 12 is of a 3-port solenoid spool valve type, has an input port 14 and a drain port 15 in addition to the output port 13, and is positioned at a home position by spring force when not energized. The output port 13 and the drain port 15 are communicated with each other, and when energized, the degree of communication of the input port 14 and the drain port 15 with respect to the output port 13 is controlled according to the current value applied to the solenoid, and the hydraulic pressure applied to the output port 13 is controlled. That is, the pressure chamber 9 of each hydraulic actuator 6
It is possible to individually control the pressure of the hydraulic oil applied to the.

An accumulator 16 is connected to the pressure chamber 9 of each hydraulic actuator 6.

A supply oil passage 17a is connected to the input port 14 of each pressure control valve 12. These supply oil passages 17a join each other on the upstream side of each pressure control valve 12 corresponding to each of the left and right wheels to form one oil passage, and on the upstream side, those corresponding to the front and rear axles join each other. It is one oil passage. An accumulator 18 is connected to the upstream side of the branch to the left and right wheels.

The drain port 15 of each pressure control valve 12 has a drain oil passage 19a
Are connected respectively. These discharge oil passages 19a are
On the downstream side of each pressure control valve 12, they merge with each other to form one oil passage, and on the downstream side, those corresponding to the front and rear axles merge with each other to form one oil passage. In addition, the back pressure chamber 10 of each hydraulic actuator 6 is provided in each discharge oil passage 19a.
The return oil passages 20 communicating with each are connected.

The hydraulic oil supply oil passage 17 where all the oil supply passages 17a to the respective pressure control valves 12 have joined together is connected to the first port 22 of the first switching valve 21. Then, the oil passage 19a from each pressure control valve 12
The hydraulic oil discharge oil passage 19 where all of the above are joined is also connected to the second port 23 of the first switching valve 21.

The first switching valve 21 is of a two-position hydraulically actuated spool valve type and has an input port 24 and a drain port 25 in addition to the first and second ports 22 and 23. And
When the pilot oil pressure applied to one end of the spool valve is less than a predetermined value, it is positioned at the home position by the spring force and the input port 24 and the first port 22 are separated from each other, and the drain port 25 and the second port 23 are separated from each other. , The first port 22 and the second port 23 are connected to each other, and when the pilot oil pressure is above a predetermined value, between the first port 22 and the input port 24, and between the second port 23 and the drain port 25. Are individually connected for communication. A throttle 26 is provided in a connection oil passage between the first and second ports 22 and 23 provided in the first switching valve 21.

The pump discharge oil passage 27 is connected to the input port 24 of the first switching valve 21.
However, a drain oil passage 28 is connected to the drain port 25 via a second switching valve and a bypass oil passage which will be described later.

A pilot oil passage 29 is provided so as to branch from the pump discharge oil passage 27, and as a result, as described above, the first pilot oil passage 29 is provided.
Pilot hydraulic pressure is applied to the switching valve 21.
Further, the pump discharge oil passage 27 is connected to the output port 34 of the pump switching valve 33 via the parallel circuit of the oil filter 30 and the bypass check valve 31 and the main check valve 32.

The bypass check valve 31 is for ensuring the amount of hydraulic oil supplied even when the oil filter 30 is clogged, and the main check valve 32 is the first switching port from the output port 34 of the pump switching valve 33. This is to allow only the flow of hydraulic oil toward the valve 21 side and to prohibit the reverse flow of hydraulic oil.

The pump switching valve 33 is a two-position electromagnetic spool valve type, and has a pump port 35 and a return port 36 in addition to the output port 34, and is positioned at the home position by spring force when not energized. The pump port 35 is connected to the return port 36, and when energized, the pump port 35 is disconnected from the return port 36 and connected to the output port 34.

The pump port 35 is connected to a discharge port 38 of a variable displacement oil pump 37 that pumps hydraulic oil from a reservoir tank T, and the return port 36 is a suction port 39 of the oil pump 37.
Is connected via a return oil passage 40.

The pump discharge oil passage 27 is connected with a pressure sensor 41, a relief valve 42 for preventing abnormal pressure rise, and an accumulator 43 for absorbing pulsation.

In addition to the input port 24 of the first switching valve 21, the first port 45 of the second switching valve 44 is connected to the pump discharge oil passage 27. The second switching valve 44 is of a two-position solenoid spool valve type, and besides the first port 45, a second port connected in series with the drain port 25 of the first switching valve 21.
46 and a drain port 47 connected to the drain oil passage 28, and when not energized, the second port 46 is closed at the home position by the spring force to close the first port 45 and the drain port 47. When the switch is energized, the first port 45 is closed and the second port 46 and the drain port 47 are connected.

On the other hand, in the drain port 25 of the first switching valve 21, as described above, in addition to the second port 46 of the second switching valve 44, the throttle 48.
And is connected to the drain oil passage 28 via a bypass oil passage 49 that bypasses the second switching valve 44. The drain oil passage 28 is connected to the reservoir tank T via an oil cooler 50 and an oil filter 51.

A pressure sensor 52 is provided in the middle of the oil passage 11 connected to the pressure chamber 9 of the hydraulic actuator 6, and a vehicle height sensor 53 is provided between the lower suspension arm 3 and the vehicle body 4. A signal necessary for controlling energization of the valve 12 is generated.

 Next, the operating procedure of the above embodiment will be described.

Under normal control during engine operation, the pump switching valve 33 and the second switching valve 44 are respectively energized so that the input port 35 and the output port 34 of the pump switching valve 33 communicate with each other, and the second switching valve 44 1 port 45 is closed. Therefore, the discharge pressure of the pump 37 acts on the first switching valve 21 via the pump discharge oil passage 27 and the pilot oil passage 29. As a result, the spool valve of the first switching valve 21 moves and the input port 24
Between the first port 22 and the drain port 25 and the second port 23
The spaces communicate with each other. Then the hydraulic oil supply passage 17
And the hydraulic oil discharge oil passage 19 are independent of each other.
The discharge hydraulic pressure generated by is supplied to the input port 14 of each pressure control valve 12. Therefore, under this condition, each pressure control valve 12 is based on the signals from the pressure sensor 52 and the vehicle height sensor 53.
By controlling the exciting current applied to the solenoid of
The hydraulic pressure supplied to the pressure chamber 9 of each hydraulic actuator 6 is controlled, and each hydraulic actuator 6 is driven to perform normal active suspension control in which the relative distance between the wheel 1 and the vehicle body 4 is adjusted. Becomes
The control valve 12 is configured such that the spool valve is biased toward the home position side as the internal pressure of the pressure chamber 9 of the hydraulic actuator 6 increases. As a result, when the tire rides on the protrusion of the road surface and the internal pressure of the pressure chamber 9 of the hydraulic actuator 6 rises sharply, this acts on the spool valve and autonomously increases the degree of communication between the output port 13 and the drain port 15. The vehicle height is maintained at high response.

On the other hand, when the pressure of the pump discharge oil passage 27 detected by the pressure sensor 41 is abnormally increased at the time of starting the engine, the power supply to the pump switching valve 33 is stopped, and the suction port 39 and the discharge port 38 of the oil pump 37 are stopped. The interval is shorted to reduce the pump load.

When the engine is stopped during parking, by stopping the power supply to the second switching valve 44, the second port 46 of the second switching valve 44 is closed, and the first port 45 and the drain port 47 are closed.
The spaces communicate. As a result, the oil pressure in the discharge oil passage 27 is released to the drain oil passage 48, and the pilot oil pressure above a predetermined value does not act on the first switching valve 21. Therefore, the first switching valve 21 is switched to the home position side, the input port 24 and the drain port 25 are closed, and the first and second ports 22 are both closed.
・ 23 will come to communicate with each other through the diaphragm 26.

As a result, the hydraulic oil supply oil passage 17 and the hydraulic oil discharge oil passage are separated from the oil pump 37 and the reservoir tank T.
19 and communicate with each other. At this time, each pressure control valve
Since the energization of 12 is stopped, the drain port 15 and the output port 13 of the 12 are communicated with each other, and as a result, the pressure chamber 9 and the back pressure chamber 10 of each hydraulic actuator 6 are communicatively connected to each other in a hydraulically sealed state. To be done.

Under this condition, the pressures of the pressure chamber 9 and the back pressure chamber 10 are balanced, so that substantial oil movement does not occur as long as the vehicle body is stationary, and oil leakage of the piston seal portion of the hydraulic actuator 6 occurs. Displacement of the piston due to, for example, a decrease in vehicle height is avoided. On the other hand, since the hydraulic oil can freely move between the pressure chamber 9 and the back pressure chamber 10 of each hydraulic actuator 6, the force applied to one wheel is the reaction force to the other wheel. That is, the function as a suspension related to all wheels is realized. Therefore, it is possible to maintain a stable posture of the vehicle body even during a failure during traveling.

With such a function, the energization of the second switching valve 44 may be stopped not only when the engine is stopped, but also when necessary, such as when the engine fails and when the loss of auxiliary machinery of the engine is reduced.

The throttle 26 of the first switching valve 21 and the throttle of the bypass oil passage 49
Reference numeral 48 prevents a sudden change in system oil pressure when the first and second switching valves 21 and 44 are switched.

FIG. 2 shows another embodiment of the hydraulic control system for the active suspension system according to the present invention. The second
In the figure, parts corresponding to those of the first embodiment shown in FIG. 1 are designated by the same reference numerals as in FIG. In this embodiment, the hydraulic oil supply oil passage 17 and the pump discharge oil passage 27 are directly connected to each other so that the switching valve 60 can connect and disconnect between the hydraulic oil supply oil passage 17 and the hydraulic oil discharge oil passage 19. It has become.

The switching valve 60 is of a two-position electromagnetic spool valve type, has a first port 62 connected to the pump discharge oil passage 27 via a throttle 61, and has a throttle 63 in the middle of the hydraulic oil discharge oil passage 19. It has a second port 64 and a drain port 65 which are connected in parallel with the drain port 65.
And the second port 64 is closed and the power is turned on, the first port 62 is closed and the second port 64 is also a drain port.
It is designed to connect to 65.

The hydraulic oil discharge oil passage 19 is connected to the drain oil passage 28 by the opening / closing valve 66.
Is selectively connected to. This on-off valve 66 is of a two-position solenoid spool valve type, and when not energized, it is located at the home position by spring force and shuts off the communication between the hydraulic oil discharge oil passage 19 and the drain oil passage 28 to energize it. At times, communication between the hydraulic oil discharge oil passage 19 and the drain oil passage 28 is established.

In the present embodiment, during normal control during engine operation, the pump switching valve 33, the switching valve 60, and the opening / closing valve 66 are energized. As a result, the first port 62 of the switching valve 60 is closed, the communication between the hydraulic oil supply oil passage 17 and the hydraulic oil discharge oil passage 19 is cut off, and the hydraulic oil discharge oil passage 19 and the drain oil passage 19 are cut off.
Communication with 28 is established. Therefore, the same normal active suspension control as in the first embodiment is performed.

When the engine is stopped during parking, the switching valve 60 and the open / close valve 66 are deenergized. As a result, the hydraulic oil supply oil passage 17 and the hydraulic oil discharge oil passage 19 communicate with each other,
The communication between the hydraulic oil discharge oil passage 19 and the drain oil passage 28 is cut off.

At this time, the pump check oil passage 27 is disconnected from the oil pump 37 and the hydraulic oil discharge oil passage 19 is disconnected from the reservoir tank T by the check function of the main check valve 32.
Under this condition, the hydraulic oil supply oil passage 17 and the hydraulic oil discharge oil passage 19 are connected to each other.

Therefore, also in this embodiment, it is possible to obtain the same operation as that of the first embodiment. [Advantages of the Invention] As is apparent from the above description, according to the hydraulic control device of the active suspension device of the present invention, In a certain mode, including parking, the hydraulic actuators are disconnected from the oil pump and the reservoir tank, and the pressure chambers and back pressure chambers of the hydraulic actuators are connected to each other so that the hydraulic actuators are connected to each other. It is possible to avoid the pressure drop in the pressure chamber of the hydraulic actuator due to the oil leakage of the piston seal portion. Therefore, displacement of the piston of the hydraulic actuator in a specific operation mode such as when the engine is stopped is suppressed, and stable vehicle height can be maintained for a long period of time.

Further, under this condition, since the suspension function of all wheels in which the hydraulic actuators of the respective wheels are communicatively connected to each other can be obtained, it is also effective as a fail-safe control during traveling.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram showing one embodiment of a hydraulic control device for an active suspension device according to the present invention, and FIG. 2 is a hydraulic circuit diagram showing another embodiment of the present invention. 1 ... Wheel 2 ... Upper suspension arm 3 ... Lower suspension arm 4 ... Car body 5 ... Coil spring 6 ... Hydraulic actuator 7 ... Cylinder, 8 ... Piston 9 ... Pressure chamber, 10 ... Back pressure chamber 11 ... Oil passage, 12 ... Pressure Control valve 13 ... Output port, 14 ... Input port 15 ... Drain port, 16 ... Accumulator 17 ... Hydraulic oil supply oil passage, 17a ... Supply oil passage 18 ... Accumulator 19 ... Hydraulic oil discharge oil passage, 19a ... Discharge oil passage 20 ... Return passage, 21 ... First switching valve 22 ... First port, 23 ... Second port 24 ... Input port, 25 ... Drain port 26 ... Throttle, 27 ... Pump discharge oil passage 28 ... Drain oil passage, 29 ... Pilot oil passage 30 ... Oil filter, 31 ... Bypass check valve 32 ... Main check valve 33 ... Pump switching valve, 34 ... Discharge port 35 ... Pump port, 36 ... Return port 37 ... Oil pump, 38 ... Discharge port 39 ... Suction port, 40 ... return Oil passage 41 ... Pressure sensor, 42 ... Relief valve 43 ... Accumulator, 44 ... Second switching valve 45 ... First port, 46 ... Second port 47 ... Drain port, 48 ... Throttle 49 ... Bypass oil passage, 50 ... Oil cooler 51 ... Oil filter, 52 ... Pressure sensor 53 ... Vehicle height sensor, 60 ... Switching valve 61 ... Throttle, 62 ... First port 63 ... Throttle, 64 ... Second port 65 ... Drain port, 66 ... Open / close valve

Continuation of front page (72) Inventor Eiki Noro 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (56) Reference JP-A-2-60817 (JP, A) JP-A-3-112710 (JP, A) Actually opened Sho 62-145711 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A plurality of pressure chambers defined by pistons and a back pressure chamber, wherein a plurality of pressure chambers are arranged to change the relative distance between the wheel and the vehicle body in accordance with the pressure of hydraulic oil supplied to the pressure chambers. Hydraulic actuators provided on each of the wheels, a supply oil passage for supplying hydraulic oil from an oil pump to each pressure chamber of each hydraulic actuator, and a hydraulic oil reservoir tank for supplying hydraulic oil from the pressure chambers of each hydraulic actuator. And a discharge oil passage for returning to each of the hydraulic actuators,
Hydraulic control of an active suspension device having a pressure control valve capable of controlling the connection between the supply oil passage and the discharge oil passage to each pressure chamber to individually control the pressure of the hydraulic oil applied to each pressure chamber. A device is provided with a return passage communicating the back pressure chamber of each hydraulic actuator with the discharge oil passage, and connecting the supply oil passage with the oil pump and the discharge oil passage with the reservoir tank. A switching circuit capable of selectively interrupting the communication is provided, and when the switching circuit is interrupted, the supply oil passages and the discharge oil passages to the hydraulic actuators are connected to each other. A hydraulic control device for an active suspension device characterized by the above.