JP3214358B2 - Vehicle steering control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle steering control device. The steering control device includes an auxiliary steering mechanism, which may be referred to as power steering, or includes an automatic steering mechanism together with the auxiliary steering mechanism.

[0002]

2. Description of the Related Art Auxiliary steering having a reservoir tank, a pump, a control valve connected to the pump and the reservoir tank for controlling pressure and direction by a steering force of a steering wheel, and a power cylinder connected to a steering linkage. A vehicle having a mechanism may further include an automatic steering mechanism that is connected to the pump via a switching valve and has a second control valve that controls pressure and direction based on a traveling state of the vehicle (Japanese Patent Application Laid-Open (JP-A) No. H11-163873). No. 7-132843). In manual steering, the pressure and direction to be applied to the power cylinder are controlled by the control valve of the auxiliary steering mechanism, and in automatic steering, the pressure and direction to be applied to the power cylinder are controlled by the second control valve of the automatic steering mechanism. .

[0003]

In a vehicle equipped with an auxiliary steering mechanism, it is preferable that steering be performed without assistance by the auxiliary steering mechanism at the start of steering, thereby improving a so-called direct feeling and improving steering feeling. You.
Therefore, there is a demand for a steering control device that can improve the steering feeling with a simple structure.

On the other hand, in a steering control device having an automatic steering mechanism described in the above publication, a control valve for an auxiliary steering system and a control valve for an automatic steering system are arranged in parallel between a switching valve and a power cylinder. In addition, since an on-off valve for preventing the hydraulic pressure from flowing back from the power cylinder to the control valve of the auxiliary steering system during automatic steering is provided, the overall structure is complicated.

[0005] The present invention provides a vehicle steering control device capable of improving the steering feeling with a simple structure.

The present invention also provides a vehicle steering control device capable of improving the steering feeling with a simple structure and performing automatic steering.

[0007]

SUMMARY OF THE INVENTION The present invention provides a reservoir tank, a pump, a control valve connected to the pump and the reservoir tank for controlling pressure and direction based on a steering force of a steering wheel, and a steering linkage. A steering control device for a vehicle including an auxiliary steering mechanism having a power cylinder connected thereto, the first control device being connected to the control valve.
And a switching mechanism having a second two ports connected to the power cylinder and a third two ports connected to the reservoir tank. The switching mechanism is formed by one supply / discharge passage formed by one port of each of the first, second, and third ports, and another one port of each of the first, second, and third ports. And another supply / discharge passage. Each of the supply / discharge passages establishes a communication state between the third port and the second port and shuts off the first port when a pressure equal to or greater than a predetermined value is not generated in the first port. And control means for, when a pressure equal to or more than a predetermined value is generated in the first port, bringing the first port and the second port into communication with each other and setting the third port into a cutoff state Having.

The present invention is also a vehicle steering control device provided with an auxiliary steering mechanism and an automatic steering mechanism. The auxiliary steering mechanism includes a reservoir tank, a pump, a first control valve connected to the pump and the reservoir tank for controlling pressure and direction based on a steering force of a steering wheel, and a power cylinder connected to a steering linkage. And The automatic steering mechanism is connected to the pump and the reservoir tank, and has a second control valve that controls a pressure and a direction based on a traveling state of the vehicle. The vehicle steering control device further includes a first two ports connected to the first control valve, and a second port connected to the power cylinder.
And a third port connected to the second control valve.
And a switching mechanism having two ports. The switching mechanism includes one supply / discharge passage formed by one port of each of the first, second, and third ports,
And another one supply / discharge passage formed by another one port of each of the second and third ports. Each of the supply / discharge passages establishes a communication state between the third port and the second port and shuts off the first port when a pressure equal to or greater than a predetermined value is not generated in the first port. age,
And a control means for setting the first port and the second port to be in communication with each other and for closing the third port when the pressure equal to or more than a predetermined value is generated in the first port. .

[0009]

According to the first aspect of the invention, one of the two supply and discharge passages of the switching mechanism is selected according to the direction controlled based on the steering wheel steering force, and the pressure controlled based on the steering wheel steering force is determined. Occurs at the first port of the selected one supply / discharge passage. When the pressure generated in the first port becomes equal to or higher than a predetermined value, the first port and the second port of the one supply / discharge passage are connected to each other, and the third port is disconnected. Liquid under pressure is led into one liquid chamber of the power cylinder. At this time, since a pressure equal to or more than a predetermined pressure is not generated in the first port of another supply / discharge passage of the two supply / discharge passages of the switching mechanism, the communication between the second port and the third port is established. The liquid escapes from another liquid chamber of the power cylinder to the reservoir tank.
This assists the movement of the steering linkage in one direction.

The first port and the second port do not communicate with each other until the pressure generated in the first port of the supply / discharge passage of the switching mechanism reaches a predetermined pressure. Steering without assistance. Thereby, the direct feeling is improved, and the steering feeling can be improved. Further, since the switching mechanism is provided with two supply / discharge passages and only the control means is provided in each supply / discharge passage, the structure is simple.

According to the second aspect of the present invention, when switching to manual steering, one of the two supply / discharge passages of the switching mechanism is selected according to the direction controlled based on the steering force of the steering wheel.
A pressure controlled based on the steering force of the steering wheel is generated at a first port of the one of the selected supply / discharge passages. When the pressure generated in the first port becomes equal to or higher than a predetermined value, the first port and the second port of the one supply / discharge passage are connected to each other, and the third port is disconnected. Liquid under pressure is led into one liquid chamber of the power cylinder.
At this time, since a pressure equal to or more than a predetermined pressure is not generated in the first port of another supply / discharge passage of the two supply / discharge passages of the switching mechanism, the communication between the second port and the third port is established. And liquid escapes from another liquid chamber of the power cylinder to the reservoir tank via the second control valve. by this,
The movement of the steering linkage in one direction is assisted.

According to the second aspect of the present invention, when switching to automatic steering, one of the two supply / discharge passages of the switching mechanism is selected according to the direction controlled based on the running state of the vehicle,
The pressure controlled based on the running state of the vehicle is guided to the selected third port of the one supply / discharge passage. At this time, since no pressure is generated at the first port of each supply / discharge passage, the third port and the second port are in communication. As a result, liquid at a controlled pressure is guided to one liquid chamber of the power cylinder, and liquid from another liquid chamber of the power cylinder escapes to the reservoir tank via the second control valve. This assists the movement of the steering linkage in one direction.

The first port and the second port are not in communication with each other until the pressure generated at the first port of the supply / discharge passage of the switching mechanism reaches a predetermined pressure. Steering without assistance. Thereby, the direct feeling is improved, and the steering feeling can be improved. The switching mechanism is provided with two supply / discharge passages, each supply / discharge passage is provided with control means, and the third two ports of the switching mechanism are connected to the second control valve, and the pump and the second control valve are connected. Since the automatic steering mechanism can be configured only by interposing the switching valve between the two, the overall structure is simple.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A steering control device for a vehicle includes an auxiliary steering mechanism and an automatic steering mechanism. The auxiliary steering mechanism includes a reservoir tank, a pump, a first control valve connected to the pump and the reservoir tank for controlling pressure and direction based on a steering force of the steering wheel, and a power cylinder connected to the steering linkage. And on the other hand,
The automatic steering mechanism has a second control valve connected to the pump and the reservoir tank, and controlling a pressure and a direction based on a traveling state of the vehicle. The first control valve and the second control valve are connected to a pump via a switching valve, and are switched so that liquid under pressure from the pump passes through the first control valve or the second control valve. The first control valve can be of the rotary or spool type, which is operated with a steering wheel steering force. On the other hand, the second control valve can be of a spool type, which is operated by a controller such as a CPU.

The switching mechanism is provided between the first control valve and the power cylinder and between the second control valve and the power cylinder. The switching mechanism includes a first two ports connected to the first control valve, a second two ports connected to the power cylinder, and a third port connected to the second control valve. And two ports. One supply / discharge passage, that is, a passage for supplying and discharging liquid, is formed by one port of each of the first, second, and third ports,
Another one supply / discharge passage is formed by another one port of each of the first, second and third ports.

Each of the supply / discharge passages has a stepped hole in the casing, for example, having a circular cross section and having a diameter different from that of the casing.
The small diameter portion of this stepped hole is used as the first port,
The second port and the third port can be formed in the large diameter portion of the stepped hole. The second port and the third port are:
The position of the stepped hole in the axial direction is shifted, or the diameter of the second port is made larger than the diameter of the third port. A control means is disposed in each of the supply / discharge passages thus formed. The control means can include a valve body that can slide within the large diameter, and a spring that presses the valve body toward a step in the transition region between the large diameter portion and the small diameter portion. When a pressure equal to or higher than a predetermined value is not generated in the first port, the valve body is pressed against the step by the spring to shut off the first port,
The third port and the second port are brought into a communication state. When a pressure equal to or more than a predetermined pressure is generated in the first port and a force based on the pressure exceeds a spring force, the valve body is separated from the stepped portion, and the first port and the second port are brought into a communication state. And the third port is turned off.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 schematically showing a steering control device, a reservoir tank 10, a pump 12, a pump 1
A vehicle having an auxiliary steering mechanism connected to the fuel tank 2 and the reservoir tank 10 and having a control valve 14 for controlling pressure and direction based on a steering wheel steering force and a power cylinder 16 connected to a steering linkage (not shown). Control the steering of the vehicle. The configuration itself is known. Control valve 14
Is, on the one hand, connected to the pump 12 by a passage 13,
On the other hand, it is connected to the reservoir tank 10 by a passage 15.

A switching mechanism 20 is provided between the control valve 14 and the power cylinder 16. The switching mechanism 20 includes the control valve 1
A first two ports 22, 23 connected to the power cylinder 16 and a second two ports 24, connected to the power cylinder 16;
25, and third two ports 26, 27 connected to the reservoir tank 10. The switching mechanism 20 further includes one port 2 of each of the first, second, and third ports.
One supply / discharge passage 28 formed by 2, 24, 26
And another one supply / discharge passage 30 formed by another one port 23, 25, 27 of each of the first, second and third, and a control means 32 is provided in each supply / discharge passage. Have been.

In the embodiment shown, the switching mechanism 20 comprises two casings 34,35. Casing 34, 35
Each has a stepped hole 38 having a circular cross section and a diameter different from that of the diameter. The small diameter portion of the stepped hole 38 is used as the first ports 22 and 23, and the port 22 is connected to the passage 40.
And the port 23 through the passage 42 through the control valve 1
4 is connected. The second port 24, 25 and the third port 26, 27 are provided in the large diameter portion of the stepped hole 38 of the casing.
And the port 24 is connected to the power cylinder 16 by the passage 44 and the port 25 is connected to the power cylinder 16 by the passage 46.
In addition, port 26 is connected by passage 48 and port 2
7 is connected to the reservoir tank 10 by a passage 50. Second ports 24 and 25 and third ports 26 and 27
Means that the second port 2 is controlled by the control unit 32 described later.
When the ports 4 and 25 open, the mutual position and the aperture are determined so that the third port closes.

When the pressure greater than a predetermined level is not generated in the first ports 22 and 23 in the supply / discharge passages 28 and 30, respectively, the control means 32 controls the third ports 26 and 27 and the second port 24. , 25 in communication with each other and the first
Ports 22 and 23 are shut off, and when a predetermined pressure or more is generated in the first ports 22 and 23, the first ports 22 and 23 and the second ports 24 and 25 are connected. At the same time, the third ports 26 and 27 are turned off.

In the embodiment shown, the control means 32 comprises a valve body 52 which can slide over a large diameter portion of the stepped hole 38, and a valve body 52.
And a coil spring 54 that presses against the step portion 39 of the stepped hole 38. The coil spring 54 is connected to the casing 35.
The spring force can be adjusted by adjusting the amount of screwing of the lid 56 which is removably screwed into the casing 35 as described in connection with. First ports 22, 23
When the pressure based on this pressure exceeds the spring force of the coil spring 54, as shown by the phantom line of the valve body 52 related to the casing 34, the valve body 52 The first port 22, 23 and the second port 24, 25 are in communication with each other, and the third port 26,
27 is turned off.

The steering control device shown in FIG. 1 operates as follows. When the steering wheel, not shown, is steered, one of the two supply / discharge passages 28, 30 of the switching mechanism 20, for example, the supply / discharge passage 28, is selected by the control valve 14 according to the direction controlled based on the steering force. A pressure controlled based on the steering force of the steering wheel is generated at the first port 22 of the selected supply / discharge passage 28. When the pressure generated in the first port 22 becomes equal to or higher than a predetermined value, the valve element 52 separates from the step portion 39 as shown by a virtual line. As a result, the first port 22 and the second port 24 of the supply / discharge passage 28 are in communication with each other, and the third port 26 is in the cutoff state. It is led to one of the sixteen liquid chambers 58. At this time, the first port 2 of another supply / discharge passage 30 of the switching mechanism 20
Since no pressure equal to or higher than the predetermined pressure is generated in the third port 3, the second port 25 and the third port 27 are in communication. Then, the liquid escapes from another liquid chamber 59 of the power cylinder 16 to the reservoir tank 10 via the second port 25 and the third port 27 as indicated by B. This assists the movement of the steering linkage connected to the power cylinder 16 in one direction.

The steering control device shown in FIGS. 2 to 4 has an automatic steering mechanism in addition to the auxiliary steering mechanism. Since the auxiliary steering mechanism has substantially the same structure as that shown in FIG. 1, the same reference numerals are given and the detailed description is omitted. The automatic steering mechanism is connected to the pump 12 and the reservoir tank 10, and has a control valve 70 for controlling the pressure and the direction based on the running state of the vehicle.

The control valve 14 and the control valve 70 are connected to the pump 12 via a switching valve 72. In the illustrated embodiment, the control valve 70 is a spool valve and the switching valve 72 is a two-way valve. Inlet port 74 of pump 12 and control valve 70
The switching valve 72 is incorporated in a passage 76 connecting the return valve 75 of the control valve 70 and the reservoir tank 10 with the passage 7.
8 is connected. Two communication ports 8 of the control valve 70
0, 81 are the third ports 26, 2
7 are connected by passages 82 and 84. Furthermore, the control valve 14 is connected on the one hand to the switching valve 72 by a passage 86 and on the other hand to the reservoir tank 10 by a passage 88.

The steering control device shown in FIGS. 2 to 4 operates as follows. When the controller 90 including the CPU determines that the automatic steering should be performed, the controller 90 operates the switching valve 72 to switch to the automatic steering shown in FIG. As a result, the control valve 70 is controlled based on the running state of the vehicle. For example, when the spool 71 of the control valve 70 moves rightward in FIG. 2, the supply / discharge passage 28 of the switching mechanism 20 is selected. That is, the liquid that has reached the inlet port 74 of the control valve 70 from the pump 12 via the switching valve 72 reaches the third port 26 from the communication port 80, and flows through the supply / discharge passage 28 as indicated by C. At the same time, the pressure controlled by the control valve 70 based on the running state of the vehicle is guided to the selected supply / discharge passage 28. At this time, since pressure is not generated in the first port 22 of the supply / discharge passage 28, the third port 26 and the second port
Is in communication with the port 24. As a result, a liquid having a controlled pressure is guided to one liquid chamber 58 of the power cylinder 16. On the other hand, since no pressure is generated in the first port 23 of the supply / discharge passage 30 communicating with another liquid chamber 59 of the power cylinder 16, the second port 25 and the third port 2
7 is in communication. As a result, the power cylinder 16
The liquid in the liquid chamber 59 flows through the supply / discharge passage 30 as shown at B, and escapes from the communication port 81 of the control valve 70 to the reservoir tank 10 via the return port 75. This assists the movement of the steering linkage in one direction.

When the operation is switched to manual steering by operating the controller 90, the switching valve 72 assumes the position shown in FIG.
4 communicates with the pump 12. At this time, the spool 71 of the control valve 70 is at the neutral position. As a result, for example, the supply / discharge passage 28 of the switching mechanism 20 is selected according to the direction controlled based on the steering wheel steering force, and the pressure controlled based on the steering wheel force is selected from the first supply / discharge passage 28 of the supply / discharge passage 28.
Occurs at the port 22. The operation in this case is substantially the same as that described for the embodiment shown in FIG.
The difference is that the liquid in the liquid chamber 59 of the power cylinder 16 flows through the supply / discharge passage 30 as indicated by B, reaches the communication port 81 of the control valve 70, and returns to the reservoir tank 10 via the return port 75.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an embodiment of a vehicle steering control device according to the present invention.

FIG. 2 is a schematic diagram of another embodiment of the vehicle steering control device according to the present invention, showing a state of automatic steering.

FIG. 3 is a schematic diagram of the same vehicle steering control device as FIG. 2 and shows a state of manual steering.

FIG. 4 is a simplified schematic diagram of a switching mechanism of the same vehicle steering control device as FIG. 2, including a controller.

[Explanation of symbols]

 Reference Signs List 10 reservoir tank 12 pump 14 first control valve 16 power cylinder 20 switching mechanism 22, 23 first port 24, 25 second port 26, 27 third port 28, 30 supply / discharge passage 32 control means 34, 35 Casing 38 Stepped hole 39 Step 58, 59 Liquid chamber 70 Second control valve 72 Switching valve

Claims (2)

(57) [Claims] 1. A reservoir tank, a pump, a control valve connected to the pump and the reservoir tank for controlling a pressure and a direction based on a steering force of a steering wheel, and a power cylinder connected to a steering linkage. A steering control device for a vehicle including an auxiliary steering mechanism, wherein the first two ports are connected to the control valve, the second two ports are connected to the power cylinder, and the vehicle is connected to the reservoir tank. And a switching mechanism having a third two ports, wherein the switching mechanism comprises the first and second ports.
And a third supply / discharge passage formed by one port of each of the third and third ports, and another supply / discharge passage formed by another one port of each of the first, second and third ports. The supply / discharge passage connects the third port to the second port and shuts off the first port when a pressure equal to or more than a predetermined value is not generated in the first port. A state, and when a pressure equal to or more than a predetermined value is generated in the first port, a control in which the first port and the second port are connected to each other and the third port is closed. A steering control device for a vehicle, comprising: 2. An auxiliary steering mechanism and an automatic steering mechanism, wherein the auxiliary steering mechanism includes a reservoir tank, a pump,
A first control valve connected to the pump and the reservoir tank for controlling a pressure and a direction based on a steering force of a steering wheel; and a power cylinder connected to a steering linkage. And a second control valve connected to the reservoir tank and controlling a pressure and a direction based on a running state of the vehicle, wherein the second control valve is connected to the first control valve. Two ports of one,
A switching mechanism having a second two ports connected to the power cylinder and a third two ports connected to the second control valve, wherein the switching mechanism includes the first and second ports; And a third supply and discharge passage formed by one port of each of the first, second and third ports.
Another one formed by each other one port
Three supply / discharge passages, and each of the supply / discharge passages establishes a communication state between the third port and the second port when a predetermined pressure or more is not generated in the first port. And when the first port is in a shut-off state, and when a pressure equal to or more than a predetermined value is generated in the first port, the first port and the second port are brought into a communicating state, and the third port is connected to the third port. A steering control device for a vehicle, comprising: control means for setting a port to a shut-off state.