JPH034424B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a pressure fluid control device for a vehicle that can separately assist the steering force of a steering wheel and control various vehicle mechanisms.

(Prior art) In order to improve turning performance in recent vehicles, pressure fluid is used in the power steering device to control compliance steering of the rear wheels or roll of the vehicle body using a vehicle mechanism. A fluid control device has been proposed. As a conventional pressure fluid control device for a vehicle of this type, for example, one disclosed in Japanese Patent Laid-Open No. 57-99470 is known.

In such a pressure fluid control device that combines a power steering device and a rear wheel actuation mechanism, when driving at low speeds, the pressure of the fluid supplied to the power cylinder is high (the first (Fig. 2), since the side force is small, it is preferable to reduce the turning angle of the rear wheel by lowering the pressure of the fluid supplied to the actuator (Fig. 2). Conversely, when driving at high speed, Because the road resistance is reduced, the pressure of the fluid supplied to the power cylinder is low (Figure 1).
Since the side force becomes large, it is preferable that the pressure of the fluid supplied to the actuator is high (FIG. 2). Furthermore, in order to obtain an appropriate steering feeling at the steering wheel, the fluid pressure characteristics of the power cylinder system have a dead band region in a small range of steering torque (Fig. 3), and conversely, the toe-out effect of the rear wheels (compliance steering ), it is preferable that the fluid pressure characteristics of the actuator system have no dead zone (FIG. 4). Therefore, it is desirable that the pressure fluid of the power cylinder system and the pressure fluid of the actuator system be controlled separately.

However, in the conventional vehicle pressure fluid control device described above, the same pressure fluid controlled by one pressure control valve is supplied to the power cylinder of the power steering device and other actuators. However, there was a problem in that the fluid pressure characteristics of the power cylinder system and the fluid pressure characteristics of the actuator system could not be controlled separately.

(Objective of the invention) Therefore, the present invention uses one pressure control valve to
By controlling the pressure fluid used in the power cylinder and the pressure fluid used in the actuator using different fluid pressure characteristics, the fluid pressure characteristics of the pressure fluid used in the power steering device and the pressure fluid used in other actuators can be adjusted. The objective is to make the fluid pressure characteristics of the fluid pressure characteristics most preferable as described above.

(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 a fluid to generate pressure fluid, and one unit that controls the pressure fluid according to a steering amount of a steering wheel. A pressure control valve, a power cylinder that generates an auxiliary force using a pressure fluid controlled by the pressure control valve and reduces the steering force of the steering wheel, and a power cylinder that uses a pressure fluid controlled by the same pressure control valve. In a pressure fluid control device for a vehicle comprising an actuator for operating various vehicle mechanisms, a rotary valve is used as the one pressure control valve, and valves with different characteristics are arranged at predetermined intervals in the circumferential direction of the rotary valve. By providing an orifice and generating different fluid pressure characteristics by the orifices having different characteristics, the pressure fluid used in the power cylinder and the pressure fluid used in the actuator are controlled by different fluid pressure characteristics. It is structured as follows.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

5 and 6 are diagrams showing a first embodiment of a pressure fluid control device for a vehicle according to the present invention.

In Fig. 5, 1 is a car body, and this car body 1
In front of (upper part in the figure) are front wheels 2 as steering wheels.
A rear wheel 3 is provided at the rear of the vehicle body 1 (lower in the figure). The front wheel 2 is connected to a rack 7 via a knuckle arm 4 and a side rod 5, and a pinion gear 8 meshes with the rack 7. The rack 7 and pinion gear 8 are housed in a gear housing 6 attached to the vehicle body 1, and a power cylinder 24 is provided at one end of the gear housing 6. A pinion shaft 9 that supports the pinion gear 8 is connected to a column shaft 13 that supports a steering wheel 11 via a torsion bar (not shown). Further, as shown in FIG. 6, a valve housing 12 is provided on the pinion shaft 9 side of the torsion bar 10.
A valve shaft 15 as shown in the figure is fixed to the column shaft 13 side of the torsion bar 10, and when the steering wheel 11 is rotated and the torsion bar 10 is twisted, the valve body 14 and the valve shaft 15 are A relative rotation occurs between the two. The valve body 14 has a first import 16, and this first import 16 is connected to a first oil pump 17 (pressure fluid generating means) via an oil passage.
It communicates with The valve body 14 has a second import 19 on the side opposite to the first import 16, and this second import 19 communicates with a second oil pump 20 (pressure fluid generating means) via an oil passage. The first oil pump 17 and the second oil pump 20 have the same reservoir tank 21.
The hydraulic oil (fluid) can be pressurized and supplied as pressurized fluid. The valve body 14 has ports 22 and 23, which are connected to the first chamber 25 and the second chamber of the power cylinder 24, respectively.
It communicates with the chamber 26 via an oil passage. These first chamber 25 and second chamber 26 are connected to the power cylinder 24.
It is defined by a power piston 27 that is housed therein so as to be slidable in the axial direction. The power piston 27 is fixed to a part of the rack 7,
The power piston 27 and the rack 7 always move together. The valve body 14 also has ports 29 and 30, which are connected to a first actuator cylinder 31 and a second actuator cylinder 32, respectively, which are fixed to the vehicle body 1 through oil passages, as shown in FIG. are communicating. These first and second actuator cylinders 31, 3
2, each of which is slidably slidable in its axial direction.
Actuator piston 33 and second actuator piston 34 are fitted. The first actuator cylinder 31 and the first actuator piston 33 collectively form the first actuator 36.
The second actuator cylinder 32 and the second actuator piston 34 constitute a second actuator 37 as a whole. First actuator piston 33 and second actuator piston 34
An insulator housing 39 with an insulator rubber 38 baked and fixed therein is fixed between the insulator housing 39 and the first actuator piston 33, the second actuator piston 34, and the insulator housing 39 integrally. I have to. In FIG. 6, for convenience, the first actuator cylinder 31 is referred to as the left chamber, and the second actuator cylinder 3
2 is the right-hand chamber, and the first actuator piston 33, insulator housing 39, and second actuator piston 34 are integrally shown as one piston. Referring again to FIG. 5, a pin member 40 is baked and fixed to the substantially central portion of the insulator rubber 38, and this pin member 40 is fixed to the vehicle body 1. The insulator housing 39 is fixed to both ends of a rear wheel suspension member 42 extending in the vehicle width direction, and a differential gear housing 43 is fixed to a substantially central portion of the rear wheel suspension member 42. has been done. The rear part of the vehicle body (lower part in the figure) of the differential gear housing 43 is connected to the insulator 4.
It is elastically supported by the vehicle body 1 via 4. The distal ends of the drive shaft 46 protruding from the differential gear housing 43 to the left and right are connected to the rear wheels 3, respectively. A semi-trailing arm 47 is interposed between the rear wheel suspension member 42 and the rear wheel 3.
When the side force acts on the semi-trailing arm 47, it is also transmitted to the rear wheel suspension member 42, and this side force is absorbed by the elastic deformation of the insulator rubber 38. The deformation of the insulator rubber 38 at this time causes a relative angular displacement between the vehicle body 1 and the rear wheel suspension member 42, that is, the rear wheel 3, which appears as compliance steer of the rear wheel 3. 6th
In the figure, the valve shaft 15 has ports 47 and 48, and communicates with an out port 49 through a gap between the valve shaft 15 and the torsion bar 10, and further communicates with the reservoir tank 21 through an oil passage. It communicates with There are four recesses on the inner periphery of the valve body 14, and first spaces 14a to 14d are formed between the inner periphery of the valve shaft 15 and the outer periphery of the valve shaft 15.
is defined. There are four flat parts on the outer periphery of the valve shaft 15, which define second spaces 15a to 15d between them and the inner periphery of the valve body 14. When the valve shaft 15 is rotated clockwise in FIG. 6, the first space 14a and the second space 15 are separated.
d, orifices 51, 52, 53 in which the first space 14b and the second space 15a, the first space 14c and the second space 15b, and the first space 14d and the second space 15c are wide;
54, first import 16 and port 2
2. Ports 23 and 47 and out port 49, 2nd
import 19 and port 30, port 29 and 48
The flow rate of the hydraulic oil flowing between the outer port 49 and the outer port 49 is increased. Valve body 14, valve shaft 15, torsion bar 10, first spaces 14a to 14d, second space 15
a to 15d are rotary valves 28 as a whole.
(Pressure control valve).

Next, the effect will be explained.

When the vehicle is turning, when the driver manually rotates the steering wheel 11 in the clockwise direction in FIG. 6, the valve shaft 13 also rotates in the same direction, and the hydraulic fluid sent from the first oil pump 17 is It passes through the first import 16 and enters the valve body 14, and then the orifice 5 formed between the valve body 14 and the valve shaft 15
Pass through 1. Next to orifice 51 is port 2
2 to the outside of the valve body 14, and the hydraulic oil passes through the oil passage to the first chamber 2 of the power cylinder 24.
5. At this time, the hydraulic oil in the second chamber 26 of the power cylinder 24 passes through the oil passage to the port 23.
It enters the valve body 14 from there. The hydraulic oil then flows into the port 47 of the valve shaft 15 through the orifice 52, and is further delivered to the reservoir tank 21 from the out port 49 through the gap 50 between the valve shaft 15 and the torsion bar 10. This causes the first power cylinder 24 to
A pressure difference occurs between the chamber 25 and the second chamber 26, and the power piston 27 is forced to move due to this pressure difference. The force for forcing the power piston 27 to move is the rack 7, the side rod 5, and the knuckle arm 4.
A steering assist force is applied to the steering wheel 2 through the steering wheel 2, thereby doubling the force applied to the steering wheel 11 by the occupant. As a result, the steering force that would normally be generated by the occupant rotating the steering wheel 11 in the absence of the power cylinder 24 can be reduced.

In addition to these functions, the rotary valve 28 also performs the following functions. Second
The hydraulic oil sent from the oil pump 20 is
It passes through the import 19 into the valve body 14 and then passes through the orifice 53 to the port 30.
from there to the second actuator cylinder 32 of the second actuator 37 . At this time, the hydraulic oil in the first actuator cylinder 31 of the first actuator 36 enters the valve body 14 from the port 29 through the oil passage. The hydraulic fluid then passes through orifice 54 to port 4 of valve shaft 15.
8 and further passes through the gap 50 between the valve shaft 15 and the torsion bar 10 and is sent out from the out port 49 to the reservoir tank 21. This creates a pressure difference between the first actuator cylinder 31 and the second actuator cylinder 32, and this pressure difference causes the first and second actuator pistons 33, 34, ie the insulator housing 39 to be forcibly moved. By moving the insulator housing 39 in this manner, the eccentric elastic deformation of the insulator rubber 38 caused by the compliance steer of the rear wheel 3 can be offset, and as a result,
It is possible to prevent deterioration of turning performance due to compliance steer of the rear wheels 3 and improve turning performance.

When the vehicle speed or engine speed is high, the flow rate of hydraulic oil supplied by the first oil pump 17 decreases, and conversely, when the vehicle speed or engine speed is low, the supply flow rate increases. Therefore, when driving at low speeds, the steering wheel 2 can be easily steered by overcoming large road resistance, and at the same time, it is possible to prevent deterioration of vehicle directionality due to excessive steering of the steering wheels 2 when driving at high speeds. Can be done. On the other hand, in the second oil pump 20, when the vehicle speed or engine speed is high, the flow rate of hydraulic oil supplied is increased, and conversely, when the vehicle speed or engine speed is low, the flow rate is decreased. . Therefore, when driving at low speeds, the compliance steer of the rear wheels 3 that occurs in response to small side forces acting on the rear wheels 3 can be suppressed to a small level, and when driving at high speeds, it is possible to suppress the compliance steer that occurs in response to the large side forces acting on the rear wheels 3. Accordingly, large compliance steer occurring in the rear wheels 3 can be prevented.

Further, the orifice (for example, 51) through which the hydraulic oil sent to the power cylinder 24 passes is not formed until the valve shaft 15 rotates beyond a small angle range (dead zone region), and during that time, the first chamber of the power cylinder 24 It is designed so that no differential pressure is generated between the second chamber 25 and the second chamber 26, that is, no steering assist force is generated. This allows the occupant to feel a resistance force to the rotation of the steering wheel 11 and obtain an appropriate steering sensation. On the other hand,
first or second actuator cylinder 31,
The orifice (for example, 53) through which the hydraulic oil sent to 32 passes has such a dead zone area that is virtually zero, and even a slight rotation of the steering wheel 11 ("play" area that occurs between pinion gear 8 and rack 7) is eliminated. ), the orifice (for example, 53) is immediately opened and the first actuator cylinder 31 and the second actuator cylinder 3 are opened.
A differential pressure is generated between the rear wheels and the first and second actuators 36, 37, so that the first and second actuators 36, 37 can respond sensitively to the compliance steer of the rear wheels.

FIG. 7 shows a second embodiment. This embodiment differs from the first embodiment in that the valve body 56
The shape of the valve shaft 57 is changed, and an oil passage 56a in the radial direction of the valve body 56 communicates with each port 58a to 58f of the valve housing 58.
In addition to ~56f, there is a valve body 5 (not shown) on the opposite side of the oil passages with respect to the center of the valve body 56.
Radial oil passages 56a' to 56f' are formed in the valve body 56 and communicate with each other through grooves formed at different axial positions between the outer circumference of the valve body 56 and the inner circumference of the valve housing 58, respectively. With such a configuration, each oil passage 56a to 56a of the valve body 56
56f and the oil passages 56a' to 56f' on the opposite side have the same hydraulic oil flow state, and an equal operating force acts within the rotary valve 60 symmetrically with respect to the center of rotation. Therefore, it is possible to prevent the valve shaft 57 from rotating smoothly due to the possibility that an equal operating force may not act symmetrically with respect to the center of rotation in the rotary valve 28 as in the first embodiment. Can be done. The same numbers are used for other parts that are the same as those in the previous embodiment.

In the first embodiment, the actuators 36 and 37 are used to prevent compliance steering of the rear wheels 3, but the actuators do not need to be limited to such applications, and the actuators 36 and 37 are used to prevent compliance steering of the vehicle body 1 due to centrifugal force when the vehicle turns. It may be an anti-roll device or any other device that can apply pressure fluid to prevent the roll phenomenon.

(Effects of the Invention) As explained above, according to the present invention, 1
By using separate pressure control valves, it is possible to separately control the fluid pressure characteristics of the pressure fluid used in the power steering device and the fluid pressure characteristics of the pressure fluid used in other actuators, so that the amounts of each can be adjusted to preferable characteristics. can.

Further, according to the second embodiment, the valve shaft can rotate smoothly and fluid pressure can be controlled smoothly.

[Brief explanation of the drawing]

Fig. 1 is a graph showing the most preferable relationship between vehicle speed and pump flow rate in a power steering device, Fig. 2 is a graph showing the most preferable relationship between vehicle speed and pump flow rate in an actuator that prevents rear wheel compliance steer, and Fig. The figure is a graph showing hydraulic characteristics with respect to steering torque, which is considered preferable in a power steering system.
The figures are graphs showing hydraulic characteristics with respect to steering torque that are considered preferable in an actuator that prevents rear wheel compliance steer, FIG. 5 is a schematic plan view showing a first embodiment of the pressure fluid control device according to the present invention, and FIG. The figure is a hydraulic circuit diagram including a sectional view of the rotary valve shown in FIG. 5, and FIG. 7 is a hydraulic circuit diagram including a sectional view of the rotary valve used in the second embodiment of the present invention. 12,58...Valve housing, 14,56
... Valve body, 15, 57 ... Valve shaft, 17 ... First oil pump, 20 ... Second oil pump, 24 ... Power cylinder, 27 ...
Power piston, 28, 60... Rotary valve, 31... First actuator cylinder, 32
...Second actuator cylinder, 33...First
Actuator piston, 34...second actuator piston, 36...first actuator,
37...second actuator, 51-54...orifice.

Claims (1)

[Scope of Claims] 1. Pressure fluid generation means that pressurizes fluid to generate pressure fluid, one pressure control valve that controls the pressure fluid according to the amount of movement of the steering wheel, and this pressure control valve. a power cylinder that generates an auxiliary force using pressure fluid controlled by the same pressure control valve to reduce the steering force of the steering wheel; and an actuator that operates various vehicle mechanisms using pressure fluid controlled by the same pressure control valve. In the pressure fluid control device for a vehicle, the one pressure control valve is a rotary valve, orifices with different characteristics are provided at predetermined intervals in the circumferential direction of the rotary valve, and the orifices with different characteristics A pressure fluid for a vehicle, characterized in that the pressure fluid used in the power cylinder and the pressure fluid used in the actuator are controlled by different fluid pressure characteristics by generating different fluid pressure characteristics depending on the pressure fluid. Control device. 2. A pressure fluid generation means for generating pressure fluid used in the power cylinder and a pressure fluid generation means for generating pressure fluid used for the actuator are provided separately, and each of these separately provided pressure fluid generation means is provided. 2. The pressure fluid control device for a vehicle according to claim 1, wherein the fluid pressure generated and the amount of fluid sent out are controlled with different characteristics depending on vehicle speed and engine rotational speed. 3. Pressure fluid control for a vehicle according to claim 1 or 2, wherein the various vehicle mechanisms are rear wheel actuators that bias the rear wheels in the steering direction of the steering wheel. Device.