JPS6092957A - Pressure fluid controller for car - Google Patents

Abstract

PURPOSE:To reduce the number of parts thus to reduce the cost, in a controller where a plurality of fluid macineries are driven by means of a plurality of control valves in accordance to the operation of steering handle, by coupling each control valve in series to single pump. CONSTITUTION:Upon rotation of a steering handle 19, knuckle arms 14R, 14L will rotate through a steering gear mechanism 20 while being assisted by a power cylinder 34 thus to rotate the front wheel 12. The pressure fluid corresponding to the steering force of said steering handle 19 will cause function of actuators 40a-40d to steer the rear wheel 13 through rotation around a pin 27 of rear wheel suspension member 22. Control valves 32, 33 provided on the steering shaft 18 to control the pressure fluid to be fed/discharged against each steering means 34, 40a-40d are coupled in series to the delivery port of pump 29. In other word, the control valve 32 is coupled through piping P1 to the delivery port of pump while the control valve 33 is coupled through piping P2 to its delivery port.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a pressure fluid control device for a vehicle, and more specifically, to a device for driving a plurality of fluid devices using a plurality of control valves in response to the steering of a steering wheel. This invention relates to a pressure fluid control device that connects control valves in series to a single pump to reduce manufacturing costs.

(Prior Art) In recent years, in order to improve the turning performance of vehicles, it has been proposed to control the compliance steer of a suspension device, the roll of a vehicle body, etc. using pressure fluid of a power steering device.

An example of this type of pressure fluid control device for a vehicle is a compliance steer control device described in Japanese Patent Application Laid-Open No. 57-99470.

This compliance steer control device includes a hydraulic actuating means attached to an elastic body interposed between a rear wheel suspension device and the vehicle body, and supplies hydraulic pressure to a power cylinder of a power steering mechanism to the hydraulic actuating means. This control is performed to reduce or increase compliance steer that occurs when the vehicle is turning.

That is, the rear wheels are steered by decreasing or increasing compliance steer.

This kind of compliance steer control device steers the rear wheels in the same direction as the front wheels when steering the steering wheel, setting the turning characteristics to the understeer side, and mainly aims to improve turning performance when driving at high speeds. It is.

By the way, as is well known, in a power steering mechanism, in order to give the driver an appropriate steering feeling, the steering assist force generated by the power cylinder is controlled to be small in a high vehicle speed range, and the steering assist force generated by the power cylinder is controlled to be small in a high vehicle speed range. A region (dead zone) in which the power cylinder does not generate a steering assist force is set within a range where the applied steering force is minute.

Therefore, low hydraulic pressure is supplied to the power cylinder of the power steering mechanism at high vehicle speeds, and no hydraulic pressure is supplied when the steering force applied to the steering wheel is small.

However, when controlling compliance steer for the rear wheels, in order to achieve more stable turning, it is desirable to generate a large compliance steer in the high vehicle speed range, causing the rear wheels to deviate significantly. Furthermore, when the steering wheel is steered, it is desirable to deflect the rear wheels even if the deflection angle of the front wheels is minute (the steering force applied to the steering wheel is minute). For this reason, in a device that supplies hydraulic pressure to the power cylinder of the power steering mechanism to the hydraulic actuation means of the compliance steer control device, it is not possible to control the compliance steer control device with the best characteristics in terms of cornering performance. It was necessary to control the hydraulic pressure supplied to the compliance steer control device separately from the hydraulic pressure supplied to the power cylinder of the power steering mechanism. In other words, in order to control both the compliance steer control device and the power steering device with the best characteristics, separate pumps and control valves should be provided for the compliance steer control device and power steering mechanism, and these pumps and control valves should have different characteristics. Control was essential.

However, since there is relatively little free space in the engine room of a vehicle, there is a problem in that it is difficult to connect a plurality of pumps to the crankshaft of the engine and drive them by the engine.

(Object of the Invention) The present invention has been made in view of the above problems, and aims to reduce the number of component parts by supplying pressure fluid to multiple fluid control circuits using a single pump, and to reduce the number of component parts in each fluid control circuit. It is an object of the present invention to provide a pressure fluid control device for a vehicle that is capable of controlling pressure fluid with distinct characteristics.

(Structure of the Invention) A pressure fluid control device for a vehicle according to the present invention includes a pressure fluid generation means that pressurizes fluid in a reservoir to generate pressure fluid;
A control valve that controls the pressure fluid generated by the pressure fluid generation means in accordance with the steering of the steering handle; and a control valve that is supplied with the pressure fluid controlled by the control valve and applies a steering assist force to the steering force applied to the steering handle. a power steering fluid circuit having a power cylinder that transmits power to the steering wheel; a control valve that controls the pressure fluid generated by the pressure fluid generating means in accordance with the steering of the steering wheel; and a pressure controlled by the control valve. A pressure fluid control device for a vehicle comprising: a fluid control circuit having an actuator that is operated by being supplied with fluid, wherein a control valve of the power steering fluid circuit and a control valve of the fluid control circuit are connected to the pressure fluid generating means. and the reservoir are connected in series.

According to this pressure fluid control device for a vehicle, it is possible to supply pressure fluid to the power steering fluid circuit and other fluid control circuits using a single pressure fluid generation means.
The number of component parts is reduced, which reduces manufacturing costs.Furthermore, the power steering fluid circuit and other fluid control circuits each have a control valve, so
The pressure fluid can be controlled with separate properties.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention, and shows an outline of a vehicle steering system.

First, to explain the configuration, 11 is the vehicle body, 12R112L
indicates the front wheels, and 13R and 13L indicate the rear wheels.

The front wheels 12R and 112L each have a nockle arm 1.
It is connected to the end of the rank 16 via 4R, 14L and side rods 15R, 15L. U・Tsuku16
A pinion 17 is engaged with the steering wheel, and the pinion 17 is connected to a steering wheel 19 via a steering shaft 18. The shaft 16 and pinion 17 constitute a steering gear mechanism 20.

The rear wheels 13R113L are each swingably supported by a rear wheel suspension member 22 via semi-trailing arms 21R and 21L.

Both ends of the rear wheel suspension member 22 are elastically supported to the vehicle body 11 by pins 24R124L via insulator rubbers 23RX23L, and are fixed to the differential gear housing δ by bolts (not shown). This differential gear housing 5 also has a pin 27 via an insulator rubber 26.
It is elastically supported to the vehicle body 11 by. In addition, 28
R and 28L are drive shafts that connect the differential gear in the differential gear housing 25 and the rear wheels 13R113L.

29 is a pump (pressure fluid generating means) that pressurizes and discharges the working fluid in the reservoir 30, and the discharge boat of the pump 29 includes two first and second control valves 32.29 provided on the steering shaft 18. 33 are connected in series. That is, the discharge boat of the pump 29 is connected to the inlet port of the first control valve 32 via the pipe P, and the discharge boat of the first control valve 32 is connected to the inlet port of the second control valve 33 via the pipe P2. Further, the discharge boat of the second control valve 33 is connected to the reservoir 30 via a pipe P3. These first and second control valves 32 and 33 control the pressure fluid discharged by the pump 29 to have different characteristics, and the first control valve 324 (also has the aforementioned dead zone set therein).

The first control valve 32 is connected to a steering cylinder 34 provided in the rank 16 by piping pQ, P, and supplies the supplied pressure fluid to the steering/% steering of the steering wheel 19 (in the embodiment, The steering force applied to the handle 19) is controlled and supplied to the power cylinder 34. That is, this first
The control valve 32 has four variable orifices 32a whose flow path area changes according to the steering force applied to the steering handle 19.
, 32b, 32G, 32d, and the variable orifice 3
Pressure fluid is controlled by 2a132b and 32C132d.

In the power cylinder 34, a piston 36 fixed to a rack 16 is slidably fitted into a cylinder body 35 provided on the vehicle body 11, and two fluid chambers 37 and 38 are defined. This power cylinder 34 generates a steering assist force corresponding to the pressure difference between the fluid chambers 37 and 38 to press the rack 16.

Additionally, a flow control valve 42 is provided between the pipe P1 and the pipe P2.
A bypass pipe PB provided with a bypass pipe PB is arranged in parallel with the first control valve 32. This bypass pipe PB short-circuits the discharge port of the pump 29 and the artificial port of the second control valve 33, and the flow rate control valve 42 is connected to a control circuit 43 to change the amount of pressure fluid flowing inside the bypass pipe PB. do. The control circuit 43 is connected to a vehicle speed sensor 44 that detects vehicle speed, and controls the amount of pressure fluid flowing through the bypass pipe PB based on the vehicle speed. This control circuit 43 controls the fluid control valve 42 so that the flow rate flowing through the bypass pipe PB is increased in a high vehicle speed range, and the amount of pressure fluid supplied from the pump 29 to the first control valve 32 is decreased.

Note that the first control valve 32 and power cylinder 3 described above
4 constitutes a power steering device (power steering fluid circuit 39), and bypass pipe PB and flow rate control valve 42 constitute flow rate m node means 45.

The second control valve 33 connects four actuators 40a, 40b, 40c, and 40d interposed between the rear wheel suspension member 22 and the vehicle body 1 via pipes PG and P7.
is connected to. Like the first control valve 32 described above, this second control valve 33 also has four variable orifices 74 whose flow path area changes in response to the steering force applied to the steering handle 19. 33 c.

33d, and directs the supplied pressure fluid to the steering handle 19.
Each actuator 4 is controlled according to the steering force applied to the
0a, 40b, 40c, and 40d.

The actuators 40a, 40b, 40c, and 40d are connected to the vehicle body 11 and the rear wheel suspension member 22 by a heavy joint, and are insulator rubbers 23R, 2 by the action of pressure fluid supplied from the second control valve 33.
3L and attach the rear wheel suspension member 22 to pin 2.
Rotate around 7.

That is, the actuators 40a, 40b, 40c.

40d biases the rear wheels 13R and 13L by rotating the rear wheel suspension member 22. These second
Control valve 33 and actuators 40a140b, 40
c and 40d constitute a compliance steer control device (fluid control circuit) 41. The compliance steer control device 41 is described in Japanese Patent Application Laid-Open No. 57-994.
Since it is described in detail in Japanese Patent Application No. 70, the explanation thereof will be simplified below.

Next, the effect will be explained.

The steering device of this vehicle biases the front wheels 12R112L and rear wheels 13R, 13L of the vehicle in accordance with the steering of the steering handle 19, and the power steering device 39 generates a steering assist force to steer the front wheels 12R112L. steering wheel]9, and the compliance steering control device 41 controls the rear wheels 13R, 13 in response to the steering of the steering wheel 19.
L is biased in the same direction as the front wheels 12R112L. As described above, the power steering device 39 is provided with a dead zone in which no steering assist force is generated when the steering force applied to the steering handle 19 is very small.

When the steering handle 19 is not being steered now, each of the first control valve 32 and the second control valve 33 has its respective variable orifice 32a, 32b, 132c, 32
d and variable orifices 33a, 33b.

Since the valves 33c and 33d have the same opening degree, the pressure fluid discharged by the pump 29 is returned to the reservoir 30 through the first control valve 32 and the second control valve 33 in sequence.

Here, when a slight steering force (within a dead band) is applied to the steering handle 19 (for example, a force for steering rightward (the same applies in the following description), the second control valve 33 has its variable orifices 33a, 33c The variable orifices 33b and 33d are narrowed in response to the steering force and opened in response to the steering force, but since a dead zone is set in the power steering device 39, each variable orifice 32a of the first control a+valve 32, The opening degrees of 32b, 32c, and 32d do not change. Therefore, the pressure fluid discharged by the pump 29 is
After flowing into the first control valve 32 from the pipe P1, it is supplied to the second control valve 33 via the pipe P2. That is, since these control valves 32 and 33 are of the center open type, even if the first control valve 32 is in an inactive state, the entire amount of the pressure fluid discharged by the pump 29 is directed to the second control valve 33. Supplied. Then, the second control valve 33 and the first control valve 32
The pressure fluid supplied through the steering wheel is controlled in response to the steering force,
High pressure fluid is supplied to the actuator 40b via piping P9.
, 40d, and low pressure fluid is supplied to piping PG.
is supplied to actuators 40a and 40c via. Therefore, the front wheels 12RS12L are biased to the right only by the steering force transmitted from the steering handle 19 via the steering gear mechanism 20, and the rear wheels 13R and 13L are biased to the right by the actuators 40a, 40b, 40c, and 40d. bias in the direction.

Next, when the steering force applied to the steering handle 19 increases, the first control valve 32 also closes its variable orifices 32b, 3.
2d is throttled in response to the steering force, variable orifices 32a and 32c are opened, and high pressure fluid is supplied to the fluid chamber 38 of the power cylinder 34. Therefore, the power cylinder 34 generates a steering assist force to press the rank 16 and reduce the steering effort of the steering handle 19. Also, the second
The control valve 33 has variable orifices 33a, 33b, 3
The deflection angle of the rear wheels 13R113L becomes larger because the flow path areas of the wheels 3c and 33d change more to supply higher pressure fluid to the actuators 40b and 40d.

At this time, as mentioned above, since each of the control valves 32 and 33 is of a center-open type, the entire amount of the pressure fluid discharged by the pump 29 is transferred to the first control valve 32 and the second control valve.
They each pass through the control valve 33, and the power steering device 39 and compliance steering control device 41 do not influence each other.

On the other hand, the flow rate of the pressure fluid flowing through the bypass pipe PB is controlled to increase at high vehicle speeds by the control circuit 43 driving the flow rate control valve 42 in accordance with the vehicle speed. Therefore, the flow rate of pressurized fluid flowing into the first control valve 32 decreases in the high vehicle speed range, and the steering assist force generated by the power cylinder 34 decreases in the high vehicle speed range, making it possible to obtain a good steering feel. That is, since the first control valve 32 utilizes the orifice effect, when the supplied flow rate decreases, the pressure of the pressure fluid supplied to the power cylinder 34 decreases, and the steering assist force generated by the power cylinder 34 decreases. It is something to do. As mentioned above, even if the flow rate flowing through the bypass pipe PB changes, the second
Since the control valve 33 is supplied with the entire discharge amount of the pump 29, the compliance steer control device 41 is not affected.

As described above, in this pressure fluid control device, the pressure fluid discharged by one pump 29 is sequentially supplied to the first control valve 32 and the second control valve 33 connected in series, so that the power is reduced. It is possible to control the steering device 39 and the compliance steer control device 41 with separate characteristics, and there is no need to provide a pump for each device 39, 41, making this fluid control device more compact and further reducing manufacturing costs. be done.

Further, in the embodiment described above, the flow rate of pressure fluid supplied from the pump 29 to the first control valve 32 of the power steering device 39 is controlled by bypassing the second control valve 33 through the bypass pipe PB in accordance with the vehicle speed. Therefore, the driver can obtain a good steering feel.

FIG. 2 shows another embodiment of the invention.

Incidentally, the same parts as those in the above-described embodiment are given the same numbers and the explanation thereof will be omitted.

In this embodiment, the second control valve of the compliance steer control device 41 is disposed on the pump side, and the first control valve 32 of the power steering device 39 is disposed on the reservoir side. and a second control valve are connected in series. Further, the first control valve 32 is provided with a bypass pipe PB that bypasses the inlet boat and the reservoir 30, and the flow rate control valve 42 provided in the bypass pipe PB is connected to a control circuit 43 to which a vehicle speed sensor 44 is connected.
The flow rate of the pressure fluid flowing through the bypass pipe PB is controlled according to the vehicle speed.

Even in this embodiment, the power steering device 39 and the compliance steer control device 41 can operate with separate characteristics due to the pressure fluid discharged by the single pump 29. In addition, in this embodiment, the bypass pipe PB connects the discharge boat of the second control valve 33 and the reservoir 3.
0 is short-circuited, the fluid pressure applied to the first control valve 32, that is, the power cylinder 34, is reduced, and the pressure resistance of the sealing material, etc., is reduced, reducing seal friction and improving the steering feel. Deterioration can be reduced.

In each of the above embodiments, the power steering device 39 is controlled in accordance with the vehicle speed by providing a bypass pipe PB that short-circuits the first control valve 32 of the power steering device 39, but the compliance steer control device 4
Needless to say, it is also possible to provide a bypass pipe that short-circuits the second control valve 33 of the vehicle 1 and to control the compliance steer control device 41 according to the vehicle speed.

(Effects of the Invention) As explained above, according to the fluid control device of the present invention, each control valve of the on-vehicle fluid control circuit is connected to the pump in series, so each fluid control circuit can be operated separately by a single pump. It becomes possible to operate the device according to its characteristics, and the entire device can be downsized, and manufacturing costs can be reduced.

Furthermore, in each of the embodiments described above, a bypass pipe is provided that short-circuits the control valve of the power steering device, and the amount of fluid supplied to the control valve is controlled based on the vehicle speed, so that the driver can obtain a good steering feeling. be able to.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a pressure fluid control device for a vehicle according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a pressure fluid control device for a vehicle according to another embodiment of the invention. 11.-1111 vehicle body, 12R112L ------1 front wheel (steering wheel), 13
R, 13L------Rear wheel, 19------One steering handle, 20---Steering gear mechanism, 29------Pump (pressure fluid generation means), 30-
---Reservoir, 32-------First control valve, 33-------Second control valve, 34--Power cylinder, 39--Power steering device () < Work steering fluid circuit), 40--actuator, 41--compliance steer control device (fluid control circuit), 42--m--flow control valve, PB--bypass pipe, 43- ----Control circuit, 44--Vehicle speed sensor, 45--Flow rate adjustment means. Patent Applicant Nissan Motor Co., Ltd. Representative Patent Attorney Ugagun Part Figure 1 11 Figure 2 1

Claims (1)

[Scope of Claims] (11) Pressurized fluid generating means that pressurizes the fluid in the reservoir to generate pressure fluid; a control valve that controls the pressure fluid generated by the pressure fluid generating means in accordance with the steering of the steering handle; a power steering fluid circuit having a power cylinder which is supplied with pressure fluid controlled by the control valve and which adds a steering assist force to the steering force applied to the steering handle and transmits it to the steering wheels; and the pressure fluid generating means. a fluid control circuit having a control valve that controls the generated pressure fluid according to the steering of the steering handle, and an actuator that is operated by being supplied with the pressure fluid controlled by the control valve. A pressure fluid control device for a vehicle, wherein a control valve of the power steering fluid circuit and a control valve of the fluid control circuit are connected in series between the pressure fluid generating means and the reservoir. (2) The power cylinder of the power steering fluid circuit applies steering assist force to steering wheels set at the front wheels, and the actuator of the fluid control circuit steers the rear wheels. (3) A bypass pipe that short-circuits the control valve of the power steering fluid circuit or the control valve of the fluid control circuit;
The pressure fluid control device for a vehicle according to claim 1, further comprising a flow control valve provided in the bypass pipe to control a flow rate of pressure fluid flowing through the bypass pipe.