JP2002154444A - Steering control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering control device for vehicle capable of preventing the steering feeling from degrading likely in the conventional arrangement caused by enlargement of the steering load of a steering wheel when an oil pump is out of operation. SOLUTION: Vehicle wheels 25a and 25b are put in steering control by a hydraulic oil supplied and exhausted relatively from the oil pump 37 to the first 32 and second oil pressure chambers 33 of a hydraulic cylinder 27 via a first 34 and a second passage 35. A pair of poppet valves 41 and 42 to be operated by a differential pressure produced by pressure control valves 43 and 44 are installed in a bypass passage 40 formed between the two passages mentioned. When the oil pump is out of operation, the poppet valves are held in the neutral position by a spring pressure given by springs 50 and 51 to open the two open ends 40a and 40b so that the bypass passage is put in communication, and thereby generation of the flow resistance of the hydraulic oil flowing substitutionally between the two oil pressure chambers is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering control device for a vehicle which applies a steering force or a steering assist force by operating a hydraulic cylinder according to a torque input from a steering input means such as a steering wheel of an automobile. .

[0002]

2. Description of the Related Art As a conventional steering control device for a vehicle of this type, for example, one disclosed in Japanese Patent Application Laid-Open No. 59-118569 is known.

[0003] Referring to Fig. 11, the steering wheel 2 is provided with a steering wheel 1 mounted on an upper end thereof.
An output shaft 3 connected to a lower end of the steering shaft 2; a rack and pinions 4a, 4b provided at a lower end of the output shaft 3;
And a hydraulic cylinder 5 which is a hydraulic actuator connected to the rack 4a, and first and second hydraulic chambers 7a, 7b separated by a piston 6 of the hydraulic cylinder 5 into a first passage 8a and a second passage. 8b, a reversible oil pump 9 for relatively supplying hydraulic pressure via the first and second passages 8b
and an electromagnetic switching valve 11 provided in the bypass passage 10 connected between the a and 8b to open and close the bypass passage 10.

When the vehicle is normally steered left and right by the steering wheel 1 while the vehicle is running, a detection mechanism 12 that detects the steering torque outputs a passage closing signal to the electromagnetic switching valve 11 via a control circuit 13. Along with
The oil pump 9 is rotated forward or backward by the pump motor 14 to relatively supply hydraulic pressure to the hydraulic chambers 7a and 7b to apply a steering assist force.

When the detecting mechanism 12 does not detect the steering torque when the vehicle is traveling straight, the electromagnetic switching valve 11 communicates the bypass passage 10 so that the hydraulic oil between the two hydraulic chambers 7a and 7b can be replaced and flown. It is supposed to.

[0006]

However, in the conventional vehicle steering control device, when a sudden disturbance is input from the road surface to the device due to, for example, kickback, the detection mechanism 12 is required. Detects such torque and outputs a passage closing signal to the electromagnetic switching valve 11 to shut off the bypass passage 10. However, at this time, the oil pump 9 is not operated. Steering assist force by hydraulic pressure cannot be obtained. As a result, the entire hydraulic circuit becomes a closed circuit, and a large flow resistance is generated in the hydraulic oil that flows between the hydraulic chambers 7a and 7b, and the steering load of the steering wheel 1 by the driver increases, and the steering is performed. Feeling may be degraded.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned problems of the conventional vehicle steering control device, and the invention according to claim 1 has an input torque output from a steering input means. The wheels are steered by hydraulic pressure relatively supplied and discharged from a hydraulic pressure source to first and second hydraulic chambers separated by a piston of a hydraulic cylinder via a first passage and a second passage. A steering control device for a vehicle to be controlled, wherein a bypass passage communicating the first passage and the second passage is provided, and both passage openings provided in the bypass passage are provided by a discharge liquid signal discharged from the hydraulic pressure source. A pair of poppet valves are provided for selectively opening and closing the ends and for connecting the first and second passages via a bypass passage when the hydraulic pressure source is not operated.

Therefore, according to the present invention, each poppet valve basically closes the bypass passage by a discharge pressure signal of a hydraulic pressure source, for example, an oil pump, so that each poppet valve is relatively close to each hydraulic pressure chamber of the hydraulic cylinder. Supply and discharge of hydraulic pressure is performed,
For example, if the operation of the oil pump is locked due to a failure of the oil pump, the oil pressure of the oil pump does not act on the poppet valve. Put the hydraulic chamber in communication. For this reason, generation | occurrence | production of the large flow resistance at the time of the displacement flow of the hydraulic oil between both hydraulic chambers can be suppressed.

The invention according to a second aspect is characterized in that a holding means for holding the both poppet valves at a neutral position when the hydraulic pressure source is not operated is provided.

[0010] The invention according to claim 3 is characterized in that a reservoir for storing a hydraulic fluid is provided upstream of the hydraulic pressure source.

According to a fourth aspect of the present invention, when the hydraulic pressure source is not operated, the reservoir and the hydraulic chambers are communicated via the poppet valve in the open state.

According to a fifth aspect of the present invention, a differential pressure generating means for generating a differential pressure between a hydraulic pressure source side and each hydraulic pressure chamber side is provided in the first passage and the second passage. The differential pressure generated by the generating means is used as a discharge signal for opening and closing the poppet valve.

According to a sixth aspect of the present invention, the hydraulic pressure source comprises:
It is characterized by comprising one oil pump that rotates forward and reverse to supply hydraulic pressure relatively to the first passage or the second passage.

The invention according to claim 7 is characterized in that the differential pressure generating means is constituted by pressure control valves provided respectively in the first and second passages.

According to an eighth aspect of the present invention, the differential pressure generating means is constituted by orifices provided in the first and second passages.

According to a ninth aspect of the present invention, each of the first and second passages is provided with a communication passage for bypassing the differential pressure generating means, and the communication passage is provided from each of the hydraulic chambers to a hydraulic pressure source. It is characterized in that a check valve that allows the flow of the hydraulic fluid only in the direction is provided.

According to a tenth aspect of the present invention, the pair of poppet valves are connected by a connecting shaft.

According to an eleventh aspect of the present invention, the holding means is constituted by a spring member for urging the on-off valve to a neutral position.

According to a twelfth aspect of the present invention, the reservoir recovers a hydraulic fluid leaked from a hydraulic pressure source.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a vehicle steering control device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention,
A steering shaft 22 to which a steering wheel 21 serving as a steering input means is connected, and an output shaft 23 at the lower end of the steering shaft 22
And a detection means 26 provided at the lower end of the output shaft 23 for detecting the steering rotational torque of the steering wheel 21 and the road surface input from the front wheels 25a and 25b. A hydraulic cylinder 27 and a hydraulic circuit 28 for supplying and discharging hydraulic pressure to and from the hydraulic cylinder 27.

In the hydraulic cylinder 27, a piston rod 30 connected to the rack penetrates a cylindrical cylinder portion 29 extending in the width direction of the vehicle body. Is fixed. In the cylinder part 29,
The left and right first hydraulic chambers 32 and the second hydraulic chambers 33 are separated by the piston 31.

The hydraulic circuit 28 includes a pair of first passages 34, 35 each having one end connected to each of the hydraulic chambers 32, 33.
And one oil pump 3 connected to the other ends of the two passages 34 and 35 and capable of rotating forward and reverse by a pump motor 36.
7 and an opening mechanism 38 provided between the two passages 34 and 35 for opening the two hydraulic chambers 32 and 33 under predetermined conditions.
And a reservoir 39 arranged upstream of the oil pump 37 and storing hydraulic oil therein.

The opening mechanism 38 is connected between the two passages 34 and 35, bypasses the oil pump 37, and is provided in the middle of the bypass passage 40.
A pair of poppet valves 41 and 42 which are open / close valves for communicating or blocking the bypass passage 40;
5 to generate a differential pressure so that each of the poppet valves 4
A pair of pressure control valves 43 and 44, which are differential pressure generating means for opening and closing the first and second valves 42, 42, are provided.

The pressure control valve 4 is provided between the first and second passages 34 and 35 and the bypass passage 40.
Communication passages 45 and 46 are connected to bypass the passages 3 and 44, and the communication passages 45 and 46 are connected to the respective hydraulic passages 32 and 33 to allow the flow of hydraulic oil in the direction of the oil pump 37. Stop valves 47 and 48 are provided, respectively.

The bypass passage 40 has a central portion connected to the reservoir 39 via a passage portion 49.

In each of the poppet valves 41 and 42, a pair of cylindrical valve holes 41b and 42b arranged substantially in series are formed in the middle of the bypass passage 40, and each of the valve holes 41b and 42b is formed. A substantially cylindrical valve element 41a, 4
2a is slidably provided. In addition, each valve hole 4
Springs 50, 51 serving as holding means are resiliently held in the pressure receiving chambers 41c, 42c provided at the rear ends of the valve bodies 41b, 42b.
The two open ends 40 having a bypass passage 40a in the middle of the bypass passage 40
The bypass passages 40 are communicated with each other by biasing the a and b in a direction to close each other to maintain the neutral position.

The valve bodies 41a and 42a are respectively connected to the center holes 40c and 40d of the bypass passage 40 connected to the front ends of the valve holes 41b and 42b. It slides relatively in the opening and closing direction due to the pressure difference between the hydraulic pressure acting in the front end portion and the hydraulic pressure supplied into the pressure receiving chambers 41c and 42c, which will be described later. Each of the valve bodies 41a and 42a has a spherical end portion serving as a valve portion connected in series by a connecting rod 52, and an annular seal fitted and fixed to an outer peripheral portion.

Further, each of the pressure receiving chambers 41c and 42c is connected to almost immediately downstream of the oil pump 36 by a pair of introduction passages 53 and 54, so that the hydraulic pressure immediately downstream of the oil pump 36 is directly supplied.

The pressure control valves 43, 44 have a pair of ball valves 43a, 44a for opening and closing the open ends of the first and second passages 34, 35 on the oil pump 37 side. Return springs 43b and 44b are provided for urging the valve bodies 43a and 44a in the closing direction with a predetermined load.

The reservoir 39 supplies and replenishes the working oil stored therein to the oil pump 37 via a supply path 55, and the oil pump 37
Hydraulic oil leaked from each of the constituent members is collected.

The pump motor 36 is controlled to rotate forward and reverse by a control current output from a controller 56 having a microcomputer. The controller 56 controls the steering input torque from the detecting means 26 or the like. The control current is output by calculation based on an information signal such as a road surface input.

Hereinafter, the operation of the present embodiment will be described. First, during normal driving of the vehicle, for example, as shown in FIG. 2, when the driver turns the steering wheel 21 to the right as shown by the arrow in the figure, the pump motor 36 is driven by a control signal from the controller 56, for example. As the forward rotation control is performed, the oil pump 37 is also driven to rotate forward. A part of the hydraulic oil discharged into the first passage 34 by such a pump action is supplied from the introduction passage 53 to the first pressure receiving chamber 4.
1c, which is higher than the hydraulic pressure of the hydraulic oil that has passed through the first pressure control valve 43, and this differential pressure causes the valve bodies 41a, 42 of the first and second poppet valves 41, 42 to move.
a is pressed rightward as shown in the figure against the spring force of the second return spring 51, and the first valve body 41a
Closes the first open end 40a and the second valve body 42a
Opens the second open end 40b.

Thus, the hydraulic oil discharged from the pump is supplied to the first hydraulic chamber 32 while pushing and opening the ball valve body 43a of the first pressure control valve 43 against the spring force of the return spring 43b. At the same time, the hydraulic oil that has flowed into the second passage 35 from the second hydraulic chamber 33 by the suction action of the oil pump 37 once flows into the other end of the bypass passage 40 as shown by the arrow. From the second communication passage 46, the second check valve 48 is opened here, and the oil is sucked into the oil pump 37 from the second passage 35 again.

Accordingly, hydraulic pressure is supplied or discharged relatively to each of the hydraulic chambers 32 and 33, and an assist force is applied to the rightward steering force of the steering wheel 21 by the driver. Thereby, the load of the rotational steering is reduced, and the operability of the steering wheel 21 can be improved.

When the clockwise steering operation is maintained, the power supply to the pump motor 36 is cut off, the hydraulic circuit 28 is closed, and the hydraulic pressure is applied to the first hydraulic chamber 32. Will be maintained.

On the other hand, when the steering wheel 21 is returned from the right rotation steering state to the original state and further left rotation steering is performed, the pump motor 3 is controlled by the controller 56.
The oil pump 37 is reversed via 6.

Therefore, as shown in FIG. 3, this time, hydraulic oil is discharged to the second passage 35 contrary to the above, and a part thereof is supplied from the second introduction passage 54 to the second pressure receiving chamber 42c. The oil pressure causes the two valve bodies 41a and 42a to slide leftward as shown in the drawing against the spring force of the spring 50, and the second valve body 42a closes the second open end 40b.
The first valve body 41a opens the first open end 40a.

Therefore, another part of the operating oil causes the ball valve body 44a of the second pressure control valve 44 to return to the return spring 4
It is pushed open against the spring force of 4b to supply hydraulic pressure into the second hydraulic chamber 33. At the same time, the hydraulic oil that has flowed into the first passage 34 from the first hydraulic chamber 32 by the suction action of the oil pump 37 once flows into one end of the bypass passage 40 as indicated by the arrow, and from there. The first communication passage 45 is entered, where the first check valve 47 is opened, and the first passage 3 is again opened.
4 is sucked into the oil pump 37.

Accordingly, the hydraulic pressure is supplied or discharged relatively to each of the hydraulic chambers 32 and 33, and an assist force is applied to the left-hand steering force of the steering wheel 21 by the driver. Thereby, the load of the rotational steering is reduced, and the operability of the steering wheel 21 can be improved.

When the oil pump 37 is locked and becomes inactive due to, for example, an electrical failure of the pump motor 36 or a mechanical failure of the oil pump 37, the oil pump 37 is stopped. Does not act on the pressure receiving chambers 41c and 42c from the introduction passages 53 and 54, the valve bodies 41 of the poppet valves 41 and 42 do not work.
a, 42a are both springs 50, 5 as shown in FIG.
It is held in the neutral position by a spring force of one. For this reason,
Each of the open ends 40c and 40d of the bypass passage 40 is in an open state, and the bypass passage 40 is communicated.
This communication state is maintained.

For this reason, even if a sudden disturbance is input from the road surface to the device due to kickback or the like at this time, and the detecting means 26 that detects this outputs information to the controller 56, the oil pump 37 is in the non-operation state. , The hydraulic assist force from the oil pump 37 cannot be obtained. However, since the hydraulic chambers 32 and 33 are connected to the bypass passage 40, the hydraulic chambers 32 and 33 are The generation of a large flow resistance of the hydraulic oil that is displaced and flowed through the flow path 40 can be effectively suppressed.

As a result, an increase in the steering load of the steering wheel 21 by the driver is suppressed, and deterioration of the steering feeling can be prevented.

In this embodiment, the operation of each of the poppet valves 41 and 42 is not controlled by an expensive electromagnetic switching valve as in the prior art, but the oil pump 37 discharges before and after the pressure control valves 43 and 44. Since the pressure is controlled by the pressure difference, the cost can be reduced.

Moreover, since the poppet valves 41 and 42 operate by directly receiving the oil pressure immediately upstream of the oil pump 37 upstream of the pressure control valves 43 and 44, the operation responsiveness is improved.

The hydraulic oil which has flowed into the front ends of the valve holes 41b and 42b is returned to the reservoir 39 through the passage 49 and is used for replenishing the oil discharged from the oil pump 37. The occurrence of so-called cavitation due to a shortage of hydraulic oil in the oil pump 37 can be prevented. That is, in this embodiment, since the hydraulic circuit 28 is a closed circuit, the hydraulic oil leaks to the outside, and if the amount of the hydraulic oil in the oil pump 37 becomes insufficient, cavitation is likely to occur. This shortage is supplied to the supply path 55
Can be replenished with the working oil in the reservoir 39 through the oil pump 37, so that the occurrence of cavitation in the oil pump 37 can be effectively prevented.

On the other hand, when the internal pressure of the oil pump 37 becomes excessively high, the surplus oil can escape into the reservoir 39 and leak from the minute gaps between the components of the oil pump 37. Since the hydraulic oil can also be collected, the load on the oil pump 37 can be reduced and the hydraulic oil can be effectively used.

Further, the communication passages 45 and 46 are provided with the check valves 47 and 48 without any spring bias.
The generation of a large flow resistance of the hydraulic oil in the direction from the oil pump 37 to the oil pump 37 is prevented. Therefore, the suction action of the oil pump 37 is improved, and the responsiveness of the pump operation is improved and the pump load is reduced.

Further, since the on-off valve is constituted by the poppet valves 41 and 42, each valve body 4 of the poppet valves 41 and 42 is provided.
Even if a foreign substance such as a contaminant is caught between the opening ends 1a and 42a and the opening ends 40a and 40b, the communication of the bypass passage 40 is ensured by this, so that the manual steering of the steering wheel 21 is performed. And the safety is enhanced.

Further, the valve body 4 of each poppet valve 41, 42
1a and 42a are connected by the connecting rod 52,
Since the two valve bodies 41a and 42a can be integrally linked, the relative opening and closing of the respective open ends 40a and 40b can be reliably performed.

Further, the pressure control valves 43 and 44 are simply connected to the ball valve bodies 43a and 44a and the return springs 43b and 4b.
4b, the structure can be simplified, the manufacturing operation is easy, and the cost can be prevented from rising.

FIG. 4 shows a second embodiment of the present invention. The basic structure such as an opening / closing mechanism is the same as that of the first embodiment.
The different point is that a detecting means for detecting a steering angle or the like is provided. That is, a steering angle sensor 56 that detects the steering angle of the steering wheel 21 is provided at the lower end of the steering shaft 22.
And stroke sensors 57 and 58 for detecting road surface input from the axial stroke amount of the piston rod 30 are provided at both ends of the piston rod 30, respectively. Further, pressure sensors 59 and 60 are provided on the hydraulic cylinder 27 side of the first and second passages 34 and 35 to detect the internal pressure of the passages 34 and 35 and check the road surface condition.

As a result, more accurate hydraulic control of the hydraulic cylinder 27 can be performed via the oil pump 37, so that the steering control of the driver can be stabilized and the load can be reduced.

FIG. 5 shows a third embodiment. The basic structure of the opening mechanism is the same as that of the first embodiment, but the reservoir 3
9 is connected to an oil pump 37 via a supply path 55, and one end of each of the passages 34 is provided on both sides of the reservoir 39.
The other ends of the extension passages 61a, 61b connected to the respective ends of the 35 on the oil pump 37 side are connected. The extension passages 61a and 61b are provided with check valves 62a and 62b that allow the operating oil to flow only from the reservoir 39 to the passages 34 and 35, respectively.

Therefore, according to this embodiment, the hydraulic oil in the reservoir 39 can be replenished and supplied to the passages 34 and 35 in addition to the oil pump 37, so that the hydraulic oil can be quickly supplied to the entire hydraulic circuit 28. Replenishment can be performed, so that not only the occurrence of cavitation in the oil pump 37 but also the occurrence of cavitation in each of the hydraulic chambers 32 and 33 can be prevented.

FIG. 6 shows a fourth embodiment, in which the basic structure is the same as that of the first embodiment. The difference is that the outside that holds the valve bodies 41a, 42a of the poppet valves 41, 42 at the neutral position is different. In addition to the respective springs 50 and 51, different springs 63a and 63b are elastically held inside. For this reason, each valve element 41a, 42a is connected to the outer springs 50, 51 by the inner springs 63a, 63b.
Is biased outward against the spring force of the above, so that it is more securely held at the neutral position.

Therefore, when the oil pump 37 is not operated, the valve elements 41a and 42a are quickly held at the neutral position, and a stable holding position can be secured.

FIG. 7 shows a fifth embodiment, in which the differential pressure generating means is replaced by first and second passages 3 instead of the pressure control valves 43 and 44.
The orifices 73 and 74 reduce the cross-sectional area of the passages 4 and 35.

Therefore, the orifices 73 and 74 not only generate differential pressures in the upstream and downstream of the passages 34 and 35 but also simplify the structure as compared with the pressure control valve and improve the workability of manufacturing. In addition, the cost can be reduced.

FIG. 8 shows a sixth embodiment, which is not a continuous bypass passage as in the first embodiment but is divided into two supply / discharge passages 64 and 65, and the opposite ends are respectively provided with air. The open reservoirs 39, 39 are connected, and the poppet valves 41, 42 are separated and operated independently of each other to open each of the open ends 64 in the respective supply / discharge passages 64, 65.
a, 65a are opened and closed. The valve bodies 41a and 42a of the poppet valves 41 and 42 are urged in the closing direction by the small spring pressures of the springs 50 and 51. However, this urging force is only for positioning in the closing direction. It does not close the open ends 64a, 65a, but the closing force is generated by the differential pressure.

Therefore, when the oil pump 37 is operating normally, each poppet valve 4
The operations of 1, 42 are controlled by the differential pressure between the upstream and downstream of the first and second passages 34, 35 via the respective pressure control valves 43, 44, but when the oil pump 37 is deactivated, ,
The valve bodies 41a and 42a of the poppet valves 41 and 42 are simply located in the closing direction by the springs 50 and 51, respectively.
Since the hydraulic chambers 32 and 33 are not closed, the hydraulic chambers 32 and 33 are relatively supplied and exhausted from the reservoirs 39 and 39, and an increase in flow resistance is suppressed, and the same operation and effect as in the first embodiment can be obtained.

FIG. 9 shows a seventh embodiment. The structure of the pressure control valves 43 and 44 of the differential pressure generating means is the same as that of the first embodiment. The open / close valve was replaced with a poppet valve and was constituted by two independent movable valves 80 and 81, respectively.

That is, each of the movable valves 80 and 81 is slidably provided in each of the valve holes 82 and 83, and opens and closes the open ends 40a and 40b formed in the annular wall.
a, 81a, pressing bodies 80b, 81b for pushing out the respective valve bodies 80a, 81a in the opening direction, and provided at respective rear end portions of the respective valve holes 82, 83 via respective introduction passages 53, 54. First and second pressure receiving chambers 80c, 81c for introducing pump discharge pressure
Provided at the front end of each of the valve holes 82 and 83, and the introduction passages 53 on the opposite sides through the signal passages 84 and 85, respectively.
First and second signal pressure chambers 80d, 8 for introducing hydraulic pressure from 54
1d and holding means provided in each of the chambers 80c, 81c, 80d, 81d to hold the two valve bodies 80a, 81a in the neutral position via the pressing bodies 80b, 81b, ie, to hold the respective open ends 40a, 40b in the open state. Springs 86a, 86
b, 87a and 87b. A reservoir 39 is connected between the movable valves 80 and 81 in the bypass passage 40.

Accordingly, during normal left-right rotation steering, for example, right rotation steering, the discharge pressure from the oil pump 37 is introduced from the first passage 34 through the first introduction passage 53 into the first pressure receiving chamber 80c. One valve body 80a slides rightward in the drawing against the spring force of the spring 86b to close the first opening / closing 40a. For this reason, the hydraulic oil discharged from the pump 37 is supplied from the first passage 34 to the first hydraulic chamber 32, and at the same time, the hydraulic oil in the second hydraulic chamber 33 opens the check valve 48 from the communication passage 46. And is sucked by the oil pump 37. Therefore, the piston rod 30 is stroked rightward to apply leftward steering assist force.

On the other hand, the oil pump 3
7, the second valve body 81a closes the second opening end 40b by the discharge pressure, so that the discharge oil is supplied to the second hydraulic chamber 33, and conversely, the right-hand steering assist force is reduced. Give.

When the oil pump 37 is not operating,
Since no oil pressure acts on both pressure receiving chambers 80c and 81c,
The two valve bodies 81a, 81b are held at the neutral position by the spring forces of the respective springs 86a, 86b, 87a, 87b via the respective pressing bodies 81a, 81b, and the two open ends 40a, 81b.
In order to open 41a, the bypass passage 40 is communicated.

As a result, the hydraulic oil between the two hydraulic chambers 32 and 33 can be replaced and flow in the bypass passage 40 without flow resistance.

FIG. 10 shows an eighth embodiment, in which valve bodies 41a and 42a of a pair of poppet valves 41 and 42, which are on-off valves provided in the middle of a bypass passage 40, are formed in a spherical shape. Outer peripheral surfaces of valve bodies 41a and 42a and respective valve holes 4
A predetermined clearance 9 between the inner peripheral surfaces of the first and second inner surfaces 1b and 42b.
0, 91 are provided, which are configured as passages. Further, the first and second passages 34 and 35 have respective hydraulic chambers 32 and 3 therein.
Check valves 92 and 93 are provided to allow the flow of hydraulic oil only in the direction from 3 to the oil pump 37.

Therefore, for example, when the steering handle 21 is steered rightward, the oil pump 37 which is normally rotated
Hydraulic oil discharged from the inlet flows into the first pressure receiving chamber 41c from the first introduction passage 53, presses the first valve body 41a rightward in the drawing to close the first opening end 40a, and the clearance as it is. The air flows into the first hydraulic chamber 32 through the one end side of the bypass passage 40 through 90. At the same time, the operating oil in the second hydraulic chamber 33 is supplied from the second passage 35 to the second check valve 93.
Is pushed open to be sucked into the oil pump 37.

In the case of left-hand steering, the hydraulic oil flows by the reverse operation.

Therefore, the application of the steering assist force during left and right rotation steering is the same as in each embodiment.

When the oil pump 37 is not operating,
The springs 50, 51 in each of the pressure receiving chambers 41c, 42c hold the two valve bodies 41a, 42a at the neutral position, open both the open ends 40a, 40b, and communicate with the bypass passage 40. , 33 is suppressed from flowing when the hydraulic oil is replaced and flows through the bypass passage 40. Therefore, deterioration of the steering feeling of the steering wheel 21 can be prevented.

The present invention is not limited to the configuration of each of the above-described embodiments. For example, the oil pressure signal from the oil pump 37 for operating the on-off valve is not limited to the discharge pressure but also the oil amount of the discharge oil. It may be. Further, the pressure difference generating means and the holding means may be configured differently.

[0074]

As is apparent from the above description, claim 1
According to the invention described in (1), both poppets close the bypass passage by a discharge liquid signal of, for example, an oil pump, which is basically a hydraulic pressure source, so that the relative hydraulic pressure to each hydraulic chamber of the hydraulic cylinder is However, when the oil pump is not operating, the oil pressure of the oil pump does not act on the poppet valve, so that the poppet valve is almost in a neutral state.
The bypass passage is opened to make both hydraulic chambers in communication. For this reason, generation | occurrence | production of the large flow resistance at the time of the displacement flow of the hydraulic oil between both hydraulic chambers can be suppressed.

As a result, an increase in the steering load by the driver is suppressed, and the deterioration of the feeling can be prevented.

Further, since the operation of the poppet valve is controlled by the discharge liquid signal of the hydraulic pressure source without using a conventional expensive electromagnetic switching valve, the cost can be reduced.

Further, since the poppet valve is used, even if foreign matter such as contaminants is interposed between the valve body and the opening end and the operation is locked, the bypass passage is an open circuit, so that manual steering is possible. And high safety.

According to the second aspect of the present invention, since both the poppet valves are forcibly held at the neutral position by the holding means, the poppet valves can be stably and reliably held at the neutral position.

According to the third and fourth aspects of the present invention, it is possible to replenish the shortage of fluid in the hydraulic pressure source by the hydraulic oil in the reservoir due to the leak, so that the occurrence of cavitation in the hydraulic pressure source can be reduced. It can be effectively prevented.

On the other hand, when the internal pressure of the hydraulic pressure source becomes excessively high, the surplus oil can be released into the reservoir, so that the load on the hydraulic pressure source can be reduced and the working efficiency of the hydraulic fluid can be reduced. improves.

According to the fifth aspect of the present invention, each poppet valve can be operated by directly receiving the discharge fluid pressure immediately upstream of the fluid pressure source upstream of the differential pressure generating means. Operation responsiveness is improved.

According to the sixth aspect of the present invention, the hydraulic pressure source for supplying the hydraulic fluid to each hydraulic pressure chamber and generating the differential pressure includes:
Since a single oil pump is used, cost can be reduced.

According to the seventh aspect of the present invention, the differential pressure generating means is constituted by a pressure control valve having a simple structure.
The manufacturing operation is facilitated, and since there is no passage restricting action unlike the orifice, the generation of large flow resistance can be prevented.

According to the eighth aspect of the invention, although the passage restricting resistance is generated by using the orifice,
Since the structure can be further simplified, reduction in manufacturing cost can be promoted.

According to the ninth aspect of the present invention, since the check valve is used, the generation of the flow resistance of the hydraulic fluid from each hydraulic chamber to the hydraulic pressure source can be suppressed. Therefore, the suction effect of the hydraulic pressure source is improved, and the operation responsiveness of the hydraulic pressure source can be improved and the operating load can be reduced.

According to the tenth aspect of the present invention, since the two poppet valves are connected by the connecting rod, the two poppet valves can be integrally linked to each other. Opening and closing can be reliably performed.

According to the eleventh aspect, the structure can be simplified by using the spring member as the holding means.

According to the twelfth aspect, the hydraulic fluid leaked from the hydraulic pressure source is collected in the reservoir, so that the hydraulic fluid can be effectively used.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of an operation when the steering wheel in the embodiment is rotated rightward.

FIG. 3 is an operation explanatory diagram when the steering wheel in the embodiment is turned leftward.

FIG. 4 is an overall schematic diagram showing a second embodiment.

FIG. 5 is an overall schematic diagram showing a third embodiment.

FIG. 6 is an overall schematic diagram showing a fourth embodiment.

FIG. 7 is an overall schematic diagram showing a fifth embodiment.

FIG. 8 is an overall schematic diagram showing a sixth embodiment.

FIG. 9 is an overall schematic diagram showing a seventh embodiment.

FIG. 10 is an overall schematic diagram showing an eighth embodiment.

FIG. 11 is a schematic diagram showing a conventional vehicle steering control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Steering wheel 26 ... Detection means 27 ... Hydraulic cylinder 28 ... Hydraulic circuit 31 ... Piston 32 ... 1st hydraulic chamber 33 ... 2nd hydraulic chamber 34 ... 1st passage 35 ... 2nd passage 36 ... Pump motor 37 ... Oil pump 38 ... Opening mechanism 39 ... Reservoir 40 ... Bypass passage 40a / 40b ... Open end 41/42 ... Poppet valve 43/44 ... Pressure control valve 45/46 ... Communication passage 47/48 ... Check valve

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Mitsuo Sasaki, Inventor 1370, Onna, Atsugi, Kanagawa Prefecture (72) Inventor Tadaharu Yokota 1370, Onna, Atsugi, Kanagawa, Japan F, Unitia Jex F Terms (reference) 3D033 EB04 EB10

Claims (12)

[Claims] 1. A first and a second hydraulic chamber separated from a hydraulic pressure source via a first passage and a second passage by a piston of a hydraulic cylinder in accordance with an input torque output from a steering input means. A steering control device for a vehicle that controls the steering of wheels by a hydraulic pressure supplied and discharged relatively to a vehicle, wherein a bypass passage communicating the first passage and the second passage is provided and discharged from the hydraulic pressure source. A pair of the first and second passages, which selectively open and close both passage open ends of the bypass passage by the discharged liquid signal and communicate the first and second passages via the bypass passage when the hydraulic pressure source is not operated. A vehicle steering control device comprising a poppet valve. 2. The vehicle steering control device according to claim 1, further comprising a holding unit that holds the poppet valves at a neutral position when the hydraulic pressure source is not operated. 3. The vehicle steering control device according to claim 1, wherein a reservoir for storing a hydraulic fluid is provided upstream of the hydraulic pressure source. 4. The vehicle steering control according to claim 3, wherein when the hydraulic pressure source is not operated, the reservoir and each of the hydraulic chambers are communicated via the poppet valve in the open state. apparatus. 5. A differential pressure generating means for generating a differential pressure between a hydraulic pressure source side and each hydraulic pressure chamber side is provided in the first passage and the second passage, and a differential pressure generated by the differential pressure generating means is provided. 5. The vehicle steering control device according to claim 1, wherein the pressure is a discharge signal for opening and closing the poppet valve. 6. An oil pump according to claim 1, wherein said hydraulic pressure source is constituted by one oil pump which rotates forward and backward to supply a hydraulic pressure to said first passage or said second passage relatively.
The steering control device for a vehicle according to any one of the above. 7. The vehicle steering control device according to claim 5, wherein said differential pressure generating means is constituted by pressure control valves provided respectively in said first and second passages. 8. The vehicle steering control device according to claim 5, wherein said differential pressure generating means is constituted by orifices provided in said first and second passages. 9. Each of the first and second passages is provided with a communication passage that bypasses the differential pressure generating means, and the hydraulic fluid flows into the communication passage from each of the hydraulic chambers only toward the hydraulic pressure source. 6. A non-return valve for permitting a pressure is provided.
The steering control device for a vehicle according to any one of claims 1 to 8. 10. The vehicle steering control device according to claim 1, wherein the pair of poppet valves are connected by a connection shaft. 11. A vehicle steering control device according to claim 1, wherein said holding means is constituted by a spring member for urging the on-off valve to a neutral position. 12. The vehicle steering control device according to claim 3, wherein the reservoir collects hydraulic fluid leaked from a hydraulic pressure source.