JPH06336111A - Supplied flow rate controller for fluid type suspension - Google Patents

Abstract

PURPOSE:To provide a supplied flow rate controller for a fluid type suspension which can prevent the hunting of the pump discharge pressure by opening the suction passage of a pump on the start of an engine where the feeding passage is cut off by a flow control valve. CONSTITUTION:A solenoid 63 is installed in a flow rate control valve 17, and a suction passage for a pump 36 is opened by forcibly operating a spool in the opening direction on the start of an engine, and a flow control valve 8 cuts off a feeding passage by keeping the pump discharge pressure at the relief pressure of a relief valve 41, and the hunting of the supplied pump discharge pressure is prevented only from an orifice 42.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid type suspension for controlling suspension characteristics of a vehicle, and more particularly to a fluid type suspension suitable for controlling a supply flow rate of a fluid type suspension in an active suspension system during engine starting. .

[0002]

2. Description of the Related Art An active suspension device for controlling suspension characteristics of a vehicle in accordance with various conditions such as road conditions, running conditions, steering conditions, etc. has been developed in various ways, and an example thereof is shown in FIG. There is something like this. In this active suspension device, the working fluid stored in the reservoir tank assembly 1 is sucked in by the pump assembly 2 and is sent to each control valve assembly 4F, 4R via the pump accumulator 30, the multi-valve 3, and the accumulator 54 for accumulating pressure. Each control valve assembly 4F, 4R is supplied with a hydraulic actuator 5 which is a fluid pressure cylinder interposed between each wheel of the vehicle and the vehicle body.
The fluid pressure to FL to 5RR is controlled according to a command value for achieving the target vehicle height from the current vehicle height to obtain desired suspension characteristics.

In such a conventional active suspension apparatus, a working oil is mainly used as the working fluid. In order to pressurize the working oil to obtain a desired supply fluid pressure, the volume is usually constant. A fixed capacity pump is used. This pump is generally driven by the rotational force of the main internal combustion engine (engine), and excess hydraulic pressure is relieved by a relief valve. However, in order to reduce the energy consumption of the hydraulic system, it is desired that the pump has a variable displacement so that only the pump flow rate suitable for the load is discharged. As such a variable displacement pump, for example, Japanese Patent Laid-Open No. 3-213683. Some are described in the official gazette. This variable displacement pump, as shown in FIG. 9 and FIG.
A flow rate control valve 17 is provided in the suction passage of the fixed capacity oil pump 36. This flow control valve 17 is
It has a spool 61 which is constantly biased in the opening direction by an elastic body such as a return spring 60 and which introduces the discharge pressure of the oil pump 36 as a pilot pressure in the closing direction. Therefore, as shown in FIG. 10, when the discharge pressure of the oil pump 36 becomes high, the spool 61 is moved in the closing direction, and in the case of FIGS. As described above, the discharge flow rate of the oil pump also decreases.

In the active suspension device using such a variable displacement oil pump, the flow rate is controlled so that the discharge pressure is kept constant by the pressure compensating action of the pump. The surplus flow rate is eliminated, the heat generation amount of the hydraulic oil is reduced by that amount, and the energy consumption is reduced. Further, when the actuator load pressure is low, such as when the vehicle is stopped, the supply fluid pressure of the working fluid drops to the vehicle height holding pressure (about half of the normal supply pressure), so the energy consumption is further reduced. In addition,
The vehicle height holding pressure is determined by the operation check valve 45 shown in the figure.
It is set by the pilot pressure of.

When a system abnormality is detected,
That is, in the case of falling into the fail state, in order to gently return the hydraulic pressure in the hydraulic actuators 5FL to 5RR, which are the fluid pressure cylinders, to the uncontrolled vehicle height holding pressure, in this active suspension device, each control valve assembly is used. Four
A fail-safe valve 9 including an electromagnetic switching valve 47 for containing the hydraulic pressure in the F and 4R and a fixed orifice 46 provided in the return pipe 35 is provided, and the fail-safe valve 9 is in a stopped state of the engine. At, it is possible to change the vehicle height gently and maintain it in a predetermined state. In this case, the control valve assemblies 4F,
In order to contain the hydraulic pressure in the 4R, the operating check valve 45 that is closed below the vehicle height holding pressure also acts.

On the other hand, when the vehicle is parked with the engine stopped for a long time, the volume due to the oil pressure on the output side and the decrease in the oil temperature from the holding pressure immediately after the vehicle is stopped and the engine is stopped. Due to reduction, etc., the holding pressure will gradually decrease over time, and the hydraulic pressure will be lower than the neutral pressure to maintain the normal reference vehicle height, and the vehicle height will also be lower than the reference vehicle height. It is expected that the amount of change in vehicle height will increase due to the increase in pressure of the oil pump due to another engine start.

Therefore, in the conventional active suspension system, the oil pump 36 and the control valve assemblies 4 are used.
An electromagnetic switching valve 43 and a flow control valve 8 having an orifice 42 provided in a bypass passage thereof are arranged between F and 4R. According to the flow control valve 8, for example, immediately after the ignition switch is turned on and the engine is started, the solenoid is not excited and the input / output side of the electromagnetic switching valve 43 is shut off.
The oil pressure from the oil pump assembly 2 is applied to the orifice 3
2 is gradually supplied to each of the control valve assemblies 4F and 4R, and the pump assembly 2 and each control are controlled by energizing the solenoid to communicate the input and output sides of the electromagnetic switching valve 43, for example, after a predetermined time from the start of the engine. Communicates with the valve assemblies 4F and 4R. Therefore, after the hydraulic pressure generated by starting the engine is accumulated in the pump accumulator 30, the hydraulic pressure gradually supplied through the orifice 42 is accumulated in the accumulator 54 for accumulating pressure, and then each control valve assembly 4F, 4R. Is gradually supplied to each of the hydraulic actuators 5FL to 5RR. As a result, for example, the deviation from the reference vehicle height is gently corrected, so that the vehicle height change becomes gentle.

The relief pressure of the relief valve 41 is equal to that of the orifice 42 of the flow control valve 8.
It goes without saying that it is set higher than the pressure rise value that occurs as flow resistance when passing.

[0009]

However, in such a conventional hydraulic control system for a hydraulic active suspension system, the set value of the relief pressure of the relief valve 41 and the operating pressure of the flow control valve 17 are set. After the engine is started, the discharge pressure of the pump is accumulated in the pump accumulator 30 due to various factors such as the introduction location.
Since the pump discharge pressure rises, the flow rate control valve 17 operates in the closing direction, and after the flow rate control valve 17 is moved in the closing direction,
Since the hydraulic pressures of the control valve assemblies 4F and 4R are still increasing, the flow control valve 17 operates in the opening direction and the discharge pressure increases due to the decrease in the discharge pressure due to the decrease in the pump discharge flow rate. For this reason, as shown in FIG. 12, so-called hunting occurs in which the discharge pressure of the pump is repeatedly increased and decreased until the hydraulic control passage is communicated by the electromagnetic switching valve 43 and the flow control valve is turned off.
This problem may occur not only in the variable displacement pump described above but also in the variable displacement pump that controls the suction flow rate of the pump by feeding back the discharge pressure.

The present invention has been developed in view of these problems, and hunts the discharge pressure of the pump by opening the suction passage of the pump while the supply passage is blocked by the flow control valve. An object of the present invention is to provide a supply flow rate control device for a fluid type suspension that can be prevented.

[0011]

SUMMARY OF THE INVENTION A supply flow rate control device for a hydraulic suspension according to the present invention operates by using a vehicle engine as a direct or indirect rotary drive source and sucking a working fluid from a storage source to a vehicle body and wheels. A pump that discharges to a fluid pressure cylinder provided between the pump and a check valve that is disposed between the pump and the fluid pressure cylinder and that shuts in the fluid pressure of the fluid pressure cylinder when the engine is stopped; Between the fluid pressure cylinder and the fluid pressure cylinder, the working fluid passage is cut off immediately after the engine is stopped or started, or immediately thereafter, and the two are communicated with each other through a bypass passage provided with an orifice.
After that, the flow control valve that directly communicates the working fluid passage and the suction passage of the pump are provided, and are urged in the opening direction by the elastic force of a preset elastic body and the elastic force of the elastic body. Of a fluid type suspension having a spool that operates in the closing direction when the discharge side fluid pressure of the pump that is introduced against the pressure is large, and a flow control valve that variably adjusts the opening degree of the suction passage of the pump. In the supply flow rate control device, a starting period opening mechanism for opening the suction passage of the pump by operating the flow rate control valve in the opening direction at the time of starting the engine or immediately after the starting is provided. Is.

[0012]

In the system for controlling the supply flow rate of the fluid type suspension of the present invention, for example, an electromagnetic solenoid is provided in the flow rate control valve so that the spool is forcibly operated in the opening direction at the start of the engine, or the relief valve is operated. An electromagnetic solenoid is installed on the flow control valve so that the discharge pressure of the pump is forcibly relieved during engine start-up to prevent the flow control valve from operating in the closing direction, or the pilot pressure of the flow control valve is set to the orifice of the flow control valve. Introduced from the downstream pressure of, by providing a starting period opening mechanism such that the discharge pressure of the pump is relieved by a relief valve before the flow control valve operates in the closing direction during the starting period of the engine. The flow control valve shuts off the supply passage and the supply pressure of the pump is supplied only from the orifice. During the starting period of the engine, the flow control valve opens and closes. Without repeating, therefore hunting of the pump discharge pressure is prevented.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first example of an active suspension system using a supply flow rate control system for a fluid suspension of the present invention.
First, the configuration of a functional valve (multi-valve) having various functions and a hydraulic source of hydraulic oil used as a working fluid will be described. After the pulse pressure of the hydraulic oil of the reservoir tank assembly 1 is reduced by the pump accumulator 30 from the pump assembly 2, it passes through the multi-valve 3 having various functions such as filtering, regulation / control / holding of the supply pressure, and the front wheel side. A hydraulic actuator 5FL, which is pressure-controlled by the control valve assembly 4F and the rear-wheel side control valve assembly 4R, and is composed of hydraulic cylinders and the like provided on each wheel of the vehicle with control pressure output from each of them.
The suspension characteristics are controlled by 5 RR to 5 RR, and further the oil is cooled from the oil cooler 31 to the reservoir tank assembly 1 via the multi-valve 3. The hydraulic actuators 5FL to 5RR correspond to the fluid pressure cylinder of the present invention.

The reservoir tank assembly 1 includes the reservoir tank 32 and the reservoir tank 3 as in the conventional case.
Oil filter 33 installed in return side pipe 35 to 2
And a check valve 34 interposed in a bypass circuit of the oil filter 33. The pump assembly 2 includes an oil pump 36 whose suction side is connected to the reservoir tank 32 and which is rotated by a drive source such as an engine, and a check valve 37 which is built in the oil pump 36 and prevents a reverse flow of a discharge flow. The oil pump 36
And a flow rate control valve 17 provided in the suction passage of the. Of these, the flow control valve 17 has basically the same structure as that shown in FIG. 10, and has a spool 61 that is constantly urged in the opening direction by a return spring 60 and closes the spool 61. The pilot pressure to operate in the direction is introduced from the downstream side of the check valve 37. In this embodiment, even if the spool 61 is operated in the closing direction by the pilot pressure, the hydraulic oil whose flow rate is controlled via the orifice 62 is transferred to the oil pump 3.
6 is inhaled. Therefore, the flow rate control valve 17 and the oil pump 36 constitute a variable displacement oil pump, and, for example, each of the control valve assemblies 4F and 4F.
When the discharge pressure of the oil pump 36 increases due to the decrease in the hydraulic pressure consumed by each hydraulic actuator 5FL to 5RR from R, the spool is operated in the closing direction and the flow rate of the intake hydraulic oil is reduced. Control valve assemblies 4F, 4R to hydraulic actuators 5FL-5R
The discharge flow rate supplied toward R is reduced, and energy consumption can be reduced.

On the other hand, the flow control valve 17 is provided with an electromagnetic solenoid 63 which operates the spool 61 in the same direction as the return spring 60, that is, in the opening direction.
This electromagnetic solenoid 63 is excited by a controller (not shown) while a flow control valve, which will be described later, shuts off the hydraulic pressure supply path, that is, during the starting period of the engine (engine), during which the flow control valve 17 is forcibly opened. To activate. In this embodiment, the electromagnetic solenoid 63 of the electromagnetic flow control valve 17 corresponds to the starting period opening mechanism of the present invention.

The pump accumulator 30 is connected to the supply side pipe 38 from the pump assembly 2. The multi-valve 3 is a flow control valve 8 including an oil filter 39 and its check valve 40, a relief valve 41 that regulates the supply pressure, a main check valve 44, a fixed orifice 42, and an electromagnetic switching valve 43, as in the conventional case. , An operation check valve 45, a fixed orifice 46, and a fail-safe valve 9 including an electromagnetic switching valve 47.

In the multi-valve 3 of this configuration example, an oil filter 39 is connected downstream of the pump accumulator 30 in the supply side pipe 38 from the pump assembly 2, and a filter clogging formed in parallel with the filter 39 is provided. The check valve 40 is interposed in the bypass circuit at that time. Further, the downstream side of the supply side pipe 38 and the upstream side of the return side pipe 35 correspond to the pressure corresponding to each wheel of the control valve assemblies 4F, 4R via the pressure holding portion 7 and the fail-safe valve 9. It is connected to the input port i and the return port o of the control valves 6FL to 6RR.

The pressure holding portion 7 formed between the supply side pipe 38 and the return side pipe 35 on the downstream side of the oil filter 39 has a main check valve 44 disposed on the downstream side of the oil filter 39. And this main check valve 4
4 and a fixed orifice 4 installed in a bypass circuit of the electromagnetic switching valve 43.
2, a relief valve 41 connected between the upstream side of the main check valve 44 and the return side pipe 35, and the fail safe on the upstream side of the relief valve 41 in the return side pipe 35. Downstream of the valve 9, that is, the pressure control valve 6FL
The operation check valve 45 is provided with the line pressure on the side of 6RR as pilot pressure. Here, when the pilot pressure is a predetermined neutral pressure which is set in advance, the operation check valve 45 is opened to release the check valve function and bring the return side pipe 35 into the communication state, and the pilot pressure is increased. When the pressure is less than the neutral pressure, the check valve function operates to close the return side pipe 35. Here, up to the pressure holding portion 7 including the reservoir tank assembly 1, the pump assembly 2, the pump accumulator 30, and the oil filter 39 becomes the fluid pressure supply means 14.

The fail-safe valve 9 comprises a spring-offset 4-port 2-position electromagnetic switching valve 47, which is connected to a downstream side of a bypass circuit of the pressure holding portion 7 and a P-port and an operation check valve 45. R port connected to the input port and pressure control valves 6FL to 6RR
Has an A port connected to the input port i and a B port connected to the return port o of the pressure control valves 6FL to 6RR. Then, at the normal switching position (OFF state) switched by the return spring 47a, the P port and the R port are shut off and the A port and the B port are in communication with each other, and in response to a control signal from the controller described later. At the offset position where the solenoid 47b is in the ON state, a communication passage that directly communicates with the P port and the A port and a communication passage that directly communicates with the R port and the B port are formed. In addition, R of the fail-safe valve 9
The port and the B port are connected via a fixed orifice 46. The fail-safe valve 9, specifically, the electromagnetic switching valve 47 serves as the opening / closing means 15 for the control side and the supply side.

Pressure control valves 6FL to 6R of the front wheel side control valve assembly 4F and the rear wheel side control valve assembly 4R.
Each R has a three-way spool valve 10 as a spool type relief pressure reducing valve. This three-way spool valve 10
Has an input port i, a return port o, and a control pressure port c, and makes the control pressure port c, the input port i, and the return port o in a cutoff state, or the control pressure port c, the input port i, and the return port o. It has a spool that is switched to a communication state in which it communicates with one of them, and is controlled by the proportional solenoid 48 so that the supply pressure is supplied as pilot pressure to one end (the lower end in FIG. 1) of the spool. The poppet valve 49 is arranged so that the pressure of the control pressure port c is controlled to be always a pressure according to the exciting current supplied to the proportional solenoid 48 from the controller described later. As a result, the one end of the three-way spool valve 10 (the lower end in FIG. 1)
The side oil chamber becomes the operating chamber 10a, and the other side (upper end portion in FIG. 1) side oil chamber becomes the feedback chamber 10b. Incidentally, the control pressure port c of each of these spool valves 10 is, as shown in FIG. 1, the hydraulic actuators 5FL to 5R of each wheel.
It is connected to the R pressure chamber 5a.

Further, as shown in FIG. 1, the input port i
Is connected to the input / output side of the poppet valve 49 via a fixed orifice 50, and the return port o is a fixed orifice 51.
Is connected to the return side of the poppet valve 49 via
The operating chamber 10a is connected to the input / output side of the poppet valve 49 via a fixed orifice (not shown), and the feedback chamber 10b is connected to the control pressure port c via the fixed orifice 12 shown in FIG.

Further, the input port i of the three-way spool valve 10 is connected to the A port of the failsafe valve 9, the return port o is connected to the B port of the failsafe valve 9, and the control port c is further connected to the hydraulic actuator 5FL. ~ 5
It is connected to the pressure chamber 5a of the RR. Further, as shown in FIG. 1, a back pressure absorbing accumulator 53 is connected to a return side pipe 52 that communicates between the return port o of each pressure control valve 6FL to 6RR and the B port of the fail-safe valve 9.
These absorb the back pressure generated by the line resistance of the hydraulic oil flowing through the return side pipe 52 and the like. Further, an oil filter 55 and a pressure accumulator 54 are connected to the hydraulic piping between the A port of the fail-safe valve 9 and the input port i of the pressure control valves 6FL to 6RR, and the hydraulic actuators 5FL to 5RR are connected from the road surface or the like. A damping valve 56 and an accumulator 57 for absorbing the pressure fluctuation of the input unsprung vibration in the high frequency range are connected, and this hydraulic circuit is flushed between the back pressure absorption accumulator 53 and the pressure accumulation accumulator 54. The cock 58 for doing is attached. The drain pressure of each hydraulic actuator 5FL to 5RR is returned to the reservoir tank 32 through the drain filter 13 in the drain circuit, the oil filter 33, and the check valve 34.

The operation of the pressure control valves 6FL to 6RR as a suspension control device will be briefly described below. When the pressures of the feedback chamber 10b and the operating chamber 10a of the three-way spool valve 10 are balanced while the pressing force of the proportional solenoid 48 is being applied to the poppet valve 49, the spool is controlled by the control pressure port c, the supply port i, and the return port. The overlap position is cut off from the o. Therefore, the pressure in the operating chamber 10a is adjusted by the magnitude of the command current to the proportional solenoid 48, and the return springs 11a, 1 arranged at both ends of the spool are adjusted.
In order to balance the pressing force of 1b, this pilot chamber 10
The spool moves slightly until the pressure inside the feedback chamber 10b and the pressure inside the feedback chamber 10b are balanced to perform the pressure adjusting operation, and the control pressure from the control pressure port c can be controlled in proportion to the command current.

Further, there is a vibration input in the sprung resonance range (for example, around 1 Hz) having a low frequency from the road surface side, and due to the vibration input, a hydraulic pressure fluctuation occurs in the pressure chamber 5a of the hydraulic actuators 5FL to 5RR. Then, this hydraulic pressure fluctuation is transmitted to the feedback chamber 10b of the three-way spool valve 10 of the pressure control valves 6FL to 6RR, and the pressure in the feedback chamber 10b and the pressure in the pilot chamber 10a are unbalanced. Here again, the spool slightly moves so that the pressing forces of the return springs 11a and 11b arranged at both ends of the spool are balanced, and between the supply port i and the control pressure port c or between the control pressure port c and the return port o. To supply and return hydraulic oil to absorb pressure fluctuations up to a prescribed limit.

Here, the front wheel side control valve assembly 4
F and the rear wheel side control valve assembly 4R become the fluid pressure control means 16 for controlling the fluid pressure to the fluid pressure cylinder. On the other hand, as described above, the fluid pressure supply means 14, the opening / closing means 15, and the fluid pressure control means 16 are controlled by control signals from a controller (not shown). A vehicle height detection signal is input to this controller from a vehicle height sensor provided in the vicinity of the hydraulic actuators 5FL to 5RR for each wheel, and the fluid pressure control means 1 outputs a command value for achieving a target vehicle height.
6. Specifically, the pressure control valves 6FL to 6RR are sent toward the three-way spool valve 10 to control the vehicle height.

The operation of the vehicle suspension control device of this embodiment during normal running and when the ignition switch is turned on / off will be described below. For example, after the ignition switch is turned on and the engine is started, when the so-called warm-up operation is completed in the start-up period, the electromagnetic switching valve 43 of the flow control valve 8 is offset to the offset switching position so that the oil pump 36 fails safe. The valve 9 is placed in a communication state, and the discharge pressure of the oil pump 36 is supplied to the hydraulic circuit below,
Also, without exciting the solenoid 63 of the flow control valve 17,
The discharge flow rate of the oil pump 36 can be made variable so that the discharge pressure of the oil pump 36 does not become excessive.

On the other hand, in this state, the solenoid 47b of the electromagnetic switching valve 37 is excited so that the P port and A port of the fail-safe valve 9 are in communication with each other, and the R port and B port are in communication with each other. The supply line pressure output from the A port of the fail-safe valve 9 is equal to the line pressure discharged from the oil pump 36, and this line pressure is supplied to the pressure control valves 6FL to 6RR and piloted to the operate check valve 45. Since the pressure is supplied as pressure, the operating check valve 45 is opened and the pressure holding portion 7 is opened. Further, since the supply line pressure output from the A port of the fail-safe valve 9 is also supplied to the pressure accumulator 54, the pressure accumulated in these pressure accumulators 54 is also equal to the line pressure discharged from the oil pump 36. .

At this time, if the vehicle is traveling straight on a flat road in a standard loading state at a constant speed, the controller supplies the neutral pressure necessary for maintaining the standard vehicle height to the hydraulic actuators 5FL to 5RR. To supply to
An exciting current having a neutral current value is supplied to each of the pressure control valves 6FL to 6RR, so that the hydraulic actuator 5FL is supplied.
The pressure of ~ 5RR is maintained at a value equal to the neutral pressure.

When the vehicle is stopped from this running state and the ignition switch is turned off, the engine is stopped and the oil pump 36 is stopped accordingly. Therefore, the supply pressure from the pump assembly 2 suddenly increases. It becomes atmospheric pressure, but the main check valve 4
4, the pressures of the pressure control valves 6FL to 6RR, the accumulator 54 for accumulating pressure, and the accumulator 53 for absorbing back pressure do not suddenly decrease. Also,
Even if the ignition switch is turned off, the self-holding timer of the controller keeps turning on the power for a predetermined time and the attitude change suppression control such as vehicle height adjustment is continued. The supply line pressure is gradually consumed and drops. At this time, when the supply line pressure is higher than the neutral pressure, the vehicle height can be adjusted to the standard vehicle height, and the vehicle height is maintained at the standard vehicle height.

After that, when the supply line pressure drops to the neutral pressure, the operate check valve 45 is fully closed, and the return side pipe 35 from the return port of each pressure control valve 6FL to 6RR to the reservoir tank assembly 1 is cut off.
The hydraulic control system on the right side of the pressure holding unit 7 forms a closed circuit, and a pressure holding state is established. When the pressure is maintained in this way,
As the pressure of the return side pipe 35 starts to rise, the pressure of the back pressure absorbing accumulator 53 also rises, and the supply line pressure decreases in accordance with these pressure increases,
It becomes a substantially constant value when this matches the return line pressure.
The vehicle height gradually decreases as the supply line pressure decreases. In this case, the vehicle height is gradually lowered, so that the passenger does not feel uncomfortable.

After that, when the ignition switch is turned on again, the controller is powered on and the engine is started to be in the idling state, and the rotation of the oil pump 36 is also increased as the rotation of the output shaft thereof is increased. The hydraulic oil having the discharge pressure corresponding to the rotation is supplied to the supply side pipe 38.
Is supplied to. During the engine start-up period, the discharge pressure of the oil pump 36 may suddenly fluctuate due to, for example, a decrease in the temperature of the hydraulic oil, and when the vehicle is parked for a long time, the discharge pressure falls below the standard vehicle height. It is conceivable that the posture change of the vehicle body will become large in order to promptly correct the vehicle height, and for this reason, several seconds to several tens of seconds from the start of the engine, for example, 10 seconds is the starting period of the engine (engine), Attitude change suppression control is performed according to a program stored in advance in the controller.

When the engine is stopped due to the ignition switch being turned off or the like as described above, the oil pump 36
Is not driven to rotate, the fail-safe valve 9 is also in the normal position for the posture change suppression control, and the control valve assemblies 4F and 4R and the hydraulic actuators 5F are in the normal position.
The hydraulic pressure in L to 5RR is confined, and the solenoids of the flow control valve 8 and the flow control valve 17 are not excited.

From this state, the ignition switch is turned on, or the solenoid 47b of the fail-safe valve 9 is excited when the engine is started, and the solenoid 63 of the flow control valve 17 is excited to rotate the spool 61.
Is forcibly maintained in the open state, while the solenoid of the flow control valve 8 is not excited during the engine starting period so that the discharge pressure of the oil pump 36 is gradually supplied to the downstream side thereof via the orifice 42. To suppress a sudden posture change of the vehicle. In particular, when the vehicle is parked with the engine stopped for a long time, the output pressure oil leaks from the holding pressure near the neutral pressure immediately after the vehicle stops and the engine is stopped, and the volume is reduced due to the decrease in the oil temperature. As a result, the holding pressure will gradually decrease with the passage of time, and since the holding pressure will be lower than the neutral pressure for maintaining the normal reference vehicle height, the vehicle height will also be lower than the reference vehicle height,
Although the vehicle height change amount due to the pressure increase of the oil pump 36 due to the engine start increases, the vehicle height change in this case can be performed gently.

During this time, the discharge pressure of the oil pump 36 is accumulated in the pump accumulator 30 and each accumulator 54 for accumulating pressure, but the suction passage of the oil pump 36 is forcibly held by the flow control valve 17 which is forcibly held in the open state. The supply line pressure continues to rise to the relief pressure of the relief valve 41 even after the pressure accumulation, and is maintained at the relief pressure when the pressure reaches the relief pressure.

Thereafter, that is, with the end of the engine starting period, the solenoid of the flow control valve 8 is excited to enable normal suspension control, and the solenoid 63 of the flow control valve 17 is de-energized. It enables the function as the variable displacement pump. During this time, in the pressure holding portion 7, when the pilot pressure, which is the pressure at the port A of the fail-safe valve 9, exceeds the relief pilot pressure, that is, the neutral pressure, the operate check valve 45 is opened and the pressure control valve 6FL. The return port o of 6RR is communicated with the reservoir tank assembly 1 through the return side pipe 35, and the pressure holding portion 7 and the pressure control valve 6F are connected.
The supply line pressure becomes equal to the set pressure of the line pressure by establishing communication with L to 6RR, and at the same time, the attitude change suppression control in the normal state is executed by the controller.

Thereafter, the controller detects the vehicle height change caused by getting on and off the occupant or the posture change of the vehicle body due to roll, pitch, bounce, etc. while the vehicle is running, and controls the exciting currents of the command values to suppress these changes. To control the pressures of the hydraulic actuators 5FL to 5RR and suppress changes in the posture of the vehicle body. When an abnormal state such as a disconnection or a short circuit occurs in the control system for the pressure control valves 6FL to 6RR during execution of the vehicle attitude control, an abnormal state detector (not shown) detects the abnormal state and the abnormal state detection signal is turned on. Therefore, based on this, the control signal output from the controller to the fail-safe valve 9 is turned off, the fail-safe valve 9 is returned to the closed state, and the input ports i and the return ports of the pressure control valves 6FL to 6RR are returned. Since the port o is in the communication state and the pilot pressure of the operating check valve 45 is reduced, the control state shifts to the holding state by the pressure holding unit 7 in a control mode substantially similar to the case of the engine stop described above, and the vehicle height is lowered. Can be prevented and a fail-safe function can be exhibited.

The proportional electromagnetic relief valve 44 is operated at the normal time and when the ignition switch is turned on and off as described above.
Holds the spool in a position that achieves a predetermined relief pressure. FIG. 2 shows changes with time of the respective hydraulic pressures in the starting period of the engine of the present embodiment.

With the flow control valve 17 forcibly held open by the solenoid 63, the oil pump 3
Since the suction passage of 6 is opened, the pump discharge pressure continues to rise as the engine starts, and is held at the relief pressure of the relief valve 41. On the other hand, the flow control valve downstream pressure supplied via the orifice of the flow control valve 8 gradually rises, and the return pressure of the fail-safe valve 9 also gradually rises accordingly, but eventually the flow control valve downstream pressure is subjected to an operation check. At the time when the valve opening / closing pressure, that is, the neutral pressure or more, is reached, the return-side pipe 35 is in the communication state, and the return pressure is reduced to about atmospheric pressure.

After that, when the solenoid of the flow control valve 8 is excited with the end of the engine starting period, the oil pump 36 and the respective control valve assemblies 4F and 4R are communicated, that is, the function of the flow control valve is OF.
Because it becomes F, this flow control valve is OFF
The flow control valve downstream pressure suddenly rises with the passage of time, and the pump discharge pressure temporarily decreases accordingly. However, both of them eventually reach the discharge pressure determined by the pump control system such as the flow control valve 17. Stabilize. As is clear from the figure, since the flow control valve 17 is normally operated in the opening direction and the pump discharge pressure is maintained at the relief pressure during the engine starting period, the conventional hunting phenomenon is prevented. .

FIG. 3 shows a second embodiment of the supply flow rate control device for the fluid suspension of the present invention. In the hydraulic control system used in this embodiment, the flow control valve 17
Except for the above, the configuration is the same as that of FIG. Also,
The configuration related to the controller is the same except for the programs processed in the controller.

The relief valve 41 of this embodiment is arranged in the supply side pipe 38 on the upstream side of the oil filter 39, specifically, by connecting the connection portion of the pump accumulator 30 and the return side pipe 35. ing. Further, the same flow control valve 17 as that shown in FIG. 10 is used, and its pilot pressure is introduced from a position downstream of the orifice 42 of the flow control valve 8.

The change with time of each hydraulic pressure in the engine starting period of the present embodiment appears as in the case of FIG. That is,
When the engine is started, the pump discharge pressure starts to rise, and at the same time, the flow control valve downstream pressure supplied via the orifice of the flow control valve 8 also gradually rises. However, the orifice downstream pressure of the flow control valve 8 is used as the pilot pressure. Flow control valve 17 to be introduced
Then, since the downstream pressure of this flow control valve has not yet reached the discharge pressure determined by the pump control system, it is held in the open state during this time, and therefore the increased pump discharge pressure is held at that time when it becomes the relief pressure of the relief valve 41. To be done. In addition, the return pressure of the fail-safe valve 9 is eventually reduced to about atmospheric pressure when the return-side pipe 35 is in communication when the downstream pressure of the flow control valve becomes equal to or higher than the opening / closing pressure of the operate check valve, that is, the neutral pressure. To do.

After that, the flow control valve is turned off.
The change with time of each hydraulic pressure after time is the same as above. As is clear from the figure, since the flow control valve 17 is held in the open state and the pump discharge pressure is held at the relief pressure, the conventional hunting phenomenon is prevented. FIG. 4 shows a third embodiment of a supply flow rate control device for a fluid type suspension according to the present invention. The hydraulic control system used in this embodiment has the same configuration as that of FIG. 1 except for the relief valve 41 and the flow control valve 17. Also, the configuration related to the controller is the same except for the programs processed in the controller.

The relief valve 41 of this embodiment is similar to that of FIG. 1 in connection point, but the pilot operating pressure of the flow control valve 17, that is, the discharge pressure determined by the pump control system, in the spool closing direction. An electromagnetic relief valve that enables switching between the second relief pressure P ₂ lower than the set operating pressure to and the normal relief pressure is used. This switching of the relief pressure is executed by a program of the controller. Specifically, the second relief pressure that does not excite the solenoid is set when the ignition switch is turned on or the engine is started, and the solenoid is turned on at a time later than the flow control valve OFF timing. Energized to switch to normal relief pressure.

As the flow control valve 17, the same one as shown in FIG. 10 is used, and its pilot pressure is introduced from the downstream portion of the pump assembly 2 as in FIG. FIG. 5 shows changes with time of the respective hydraulic pressures in the engine starting period of the present embodiment.

That is, the pump discharge pressure starts to rise with the start of the engine, but at this time, the relief valve 41 is set to the second relief pressure lower than the discharge pressure determined by the pump control system. Is maintained at the second relief pressure from the time when the second relief pressure is reached. Then, as the flow control valve is turned off, the flow control valve downstream pressure rapidly rises to become equal to the second relief pressure, and thereafter, as the relief pressure is switched, the pump discharge pressure and the flow control valve downstream pressure increase. It rises to a discharge pressure determined by the pump control system.

During this time, the return pressure of the fail-safe valve 9 is reduced to about atmospheric pressure when the downstream pressure of the flow control valve becomes equal to or higher than the neutral pressure, as described above.
As is apparent from the figure, before the pump discharge pressure reaches the discharge pressure determined by the pump control system, the relief pressure is relieved by the second relief pressure lower than that, so that the conventional hunting phenomenon is prevented. .

FIG. 6 shows the fourth embodiment of the supply flow rate control device for the fluid type suspension of the present invention. The operation of the third embodiment of FIG. 4 is achieved by the mechanical operation of each component of the hydraulic circuit. It has been achieved. The hydraulic control system used in this embodiment is different from that shown in FIG. 1 only in the pressure holding portion 7. The configuration related to the controller is the same except for the program.

In this embodiment, the flow control valve 8 is provided in the middle of the connection path between the supply pipe 38 on the downstream side of the relief valve 41 and the return pipe 35 on the upstream side of the relief valve 41.
The electromagnetic switching valve 32 is installed, and the orifice 19 is installed upstream of the connection path. The electromagnetic switching valve 32 energizes a solenoid during the engine start period to bring the connection path into a communication state, and releases the solenoid energization to disconnect the connection path at the end of the engine start period. Further, the orifice 19 is set so that the pressure increase value of the flow resistance by the orifice is less than the second relief pressure lower than the discharge pressure determined by the pump control system.

A pilot pressure for operating the spool of the relief valve in the same direction as the biasing direction of the return spring is introduced into the relief valve 41 from a position downstream of the orifice 19 of the connection path. Further, an operate check valve 18 is provided on the upstream side of the P port of the fail-safe valve 9, and an orifice 42 of the flow control valve 8 and a main check valve 44 are provided in a bypass circuit of the operate check valve 18. . The operating pressure of the operating check valve 18 is
It is introduced from a position downstream of the orifice 19 of the connection path, and is set to be equal to the discharge pressure determined by the pump control system.

In the supply flow rate control device of this embodiment,
Since the electromagnetic switching valve 43 of the flow control valve 8 is opened during the engine start-up period, the downstream side of the orifice 19 of the connection path is at atmospheric pressure, and the relief pressure of the relief valve 41 is set by the return spring. It is the second relief pressure. In addition, since the operating check valve 18 is closed in this state,
The pump discharge pressure is held at this second relief pressure, and the system supply pressure that gradually increases is supplied via the orifice 32 to the downstream side of the fail-safe valve.

If the electromagnetic switching valve 43 is operated in the closing direction from this state when the flow control valve is OFF with the end of the engine start period, the pressure on the downstream side of the orifice 19 of the connecting path rises, and eventually the discharge determined by the pump control system. When the pressure is reached, the operate check valve 18 is operated in the opening direction to bring the supply side pipe 38 into a communication state, and the system supply pressure is also increased. On the other hand, since the increased orifice 19 downstream pressure is introduced so as to act in the same direction as the return spring biasing direction of the relief valve 41, the relief pressure of the relief valve 41 is usually higher than the second relief pressure. It becomes the relief pressure of and enables the normal operation of the system.

FIG. 7 shows a fifth embodiment of the supply flow rate control device for the fluid suspension of the present invention. The hydraulic control system used in this embodiment is the same as the hydraulic control system except for the structure of the flow control valve. The configuration is similar to that of FIG. 1, and the configuration related to the controller is the same except for the program. In this embodiment, the flow control valve 8 is provided by providing a notch in the control edge portion of the suction throttle valve spool of the flow control valve 17 or by making the spring constant of the spring for urging the spool non-linear.
The flow rate control valve 17 prevents the pump suction passage from being completely closed by reducing the rate (gradient) of the flow rate decrease with respect to the discharge pressure near the closed state (when the flow control valve is closed). That is, the open state is maintained.

FIG. 8 shows the change over time of each hydraulic pressure in this embodiment using the variable displacement pump having the flow rate characteristic of FIG. As is clear from the figure, the pump discharge pressure rises with the start of the engine, and eventually the discharge flow rate drops in FIG. However, since the slope of the discharge flow rate change with the discharge pressure rise when the flow control valve is closed is small,
The pump discharge pressure hunting converges to the flow rate and its discharge pressure when the flow control valve is closed. During this time, the downstream pressure of the flow control valve gradually rises, and the discharge pressure determined by the pump control system after the flow control valve is turned off. Rise to.

During this time, the return pressure of the fail-safe valve 9 drops to about atmospheric pressure when the downstream pressure of the flow control valve becomes equal to or higher than the neutral pressure, as described above.
As is clear from the figure, the pump discharge pressure is converged to the discharge pressure determined by the pump control system, so that the conventional hunting phenomenon is prevented.

[0056]

As described above, according to the supply flow rate control device for the fluid type suspension of the present invention, the flow control valve blocks the supply passage and the
During the start-up period of the engine to which the supply pressure of the pump is supplied, the start-up period opening mechanism prevents the flow control valve from repeatedly opening and closing, thus preventing hunting of the pump discharge pressure.

[Brief description of drawings]

FIG. 1 is a schematic hydraulic configuration diagram showing a first embodiment of an active suspension device using a supply flow rate control device for a fluid suspension of the present invention.

FIG. 2 is a time chart showing changes with time of respective hydraulic pressures in an engine starting period of the active suspension apparatus of FIG.

FIG. 3 is a schematic hydraulic configuration diagram showing a second embodiment of an active suspension device using a supply flow rate control device for a fluid suspension of the present invention.

FIG. 4 is a schematic hydraulic configuration diagram showing a third embodiment of an active suspension device using a supply flow rate control device for a fluid suspension of the present invention.

5 is a time chart showing changes with time of respective hydraulic pressures in the engine starting period of the active suspension apparatus of FIG.

FIG. 6 is a schematic hydraulic configuration diagram showing a fourth embodiment of an active suspension device using a supply flow rate control device for a fluid suspension of the present invention.

FIG. 7 is a discharge pressure flow rate characteristic diagram of a variable displacement pump showing a fifth embodiment of an active suspension apparatus using a supply flow rate control apparatus for a fluid suspension of the present invention.

8 is a time chart showing changes with time of each hydraulic pressure in the engine starting period of the active suspension apparatus of FIG. 7. FIG.

FIG. 9 is a schematic hydraulic configuration diagram showing an example of a conventional active suspension device.

10 is a schematic hydraulic configuration diagram showing an example of a variable displacement pump used in the active suspension apparatus of FIG.

11 is a discharge pressure flow rate characteristic diagram of the variable displacement pump of FIG.

FIG. 12 is a time chart showing changes with time of respective hydraulic pressures in the engine starting period of the active suspension apparatus of FIG.

[Explanation of symbols]

 1 is a reservoir tank assembly 2 is a pump assembly 3 is a multi-valve 4F, 4R is a control valve assembly 5FL to 5RR is a hydraulic actuator 6FL to 6RR is a pressure control valve 7 is a pressure holding part 8 is a flow control valve 9 is a failsafe valve 10 is Three-way spool valve 17 Flow control valve 18 Operate check valve 19 Orifice 30 Pump accumulator 36 Oil pump 41 Relief valve 45 Operate check valve 54 Accumulation pre-accumulator

Claims (1)

[Claims] 1. A pump that operates an engine of a vehicle as a direct or indirect rotary drive source, sucks a working fluid from a storage source and discharges the working fluid to a fluid pressure cylinder provided between a vehicle body and wheels, and the pump. And a check valve which is disposed between the fluid pressure cylinder and the fluid pressure cylinder and shuts down the fluid pressure of the fluid pressure cylinder when the engine is stopped, and the check valve which is disposed between the check valve and the fluid pressure cylinder to stop the engine or A flow control valve that blocks the working fluid passage immediately after startup or communicates with each other through a bypass passage having an orifice, and then directly connects the working fluid passage, and is disposed in the middle of the suction passage of the pump. When the discharge side fluid pressure of the pump, which is biased in the opening direction by the elastic force of the elastic body set in advance and is introduced against the elastic force of the elastic body, is closed. A supply flow rate control device for a fluid suspension having a spool that operates and a flow rate control valve that variably adjusts the opening degree of the suction passage of the pump, wherein the flow rate control is performed at or immediately after the engine is started. A supply flow rate control device for a fluid suspension, comprising a starting period opening mechanism for opening a suction passage of a pump by operating a valve in an opening direction.