JPH0825465B2 - Power steering device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power steering device, and more particularly to switching a switching valve by operating a steering wheel and supplying pressure oil from a pressure source to a steering cylinder to steer a wheel. The present invention relates to a power steering device.

[Outline of Invention]

A switching valve that is switched by operating the steering wheel is connected to the outside of the steering cylinder so that its axis intersects at a right angle, and a pressure oil injection valve for supplying pressure oil to the sub-cylinder to correct the cut-off delay. Is mounted on the outside of the steering cylinder and above or below the switching valve so that its axis is parallel to the steering cylinder.By compactly incorporating the control valves of the power steering device, This is intended to improve the vehicle mountability.

[Conventional technology]

In order to reduce the steering force of the steering wheel for steering the front wheels, a power steering device has been used. The power steering device is for steering using a steering cylinder, and switches the switching valve by operating the steering wheel to supply pressure oil to the steering cylinder.
The steering wheel is steered by the output of the steering cylinder.

[Problems to be solved by the invention]

In such a power steering device, since the steering wheel is operated to switch the switching valve and the pressure oil is supplied to the steering cylinder to perform steering, it takes time to switch the switching valve or increase the hydraulic pressure. It is necessary and causes delay. In order to correct such a cut-off delay, a sub-cylinder is provided, and the cut-off delay is corrected by operating the sub-cylinder prior to the steering cylinder in conjunction with the detection of the steering force sensor provided on the steering wheel. It will be possible.

However, if a sub-cylinder is provided to correct the delay, it requires a pair of left and right pressure oil injection valves for its control, or a solenoid valve for discharging oil from this pressure oil injection valve. Need. Furthermore, a switching valve for switching the supply of pressure oil to the steering cylinder must be provided. Therefore, various control valves make the power steering device large in size, require a large space, and deteriorate the mountability on the vehicle.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power steering apparatus in which control valves are compactly incorporated.

[Means for solving problems]

The present invention is a device in which a switching valve is switched by operating a steering wheel and pressure oil is supplied from a pressure source to a steering cylinder to steer a wheel, and the steering force generated in the steering wheel is detected by a steering force sensor. , The pressure oil injection valve is switched in association with the detection of the steering force sensor to supply pressure oil to the sub-cylinder to correct the cut-off delay, and the switching valve is provided on the outer side of the steering cylinder. Are arranged so as to intersect at a right angle, and the pressure oil injection valve is attached to the outer side of the steering cylinder above or below the switching valve such that the axis of the pressure oil injection valve is parallel to the steering cylinder. It is a thing.

[Action]

Therefore, a switching valve that controls the supply and switching of pressure oil to the steering cylinder and a pressure oil injection valve that cooperates with the sub-cylinder to correct the cut-off delay can be provided in series outside the steering cylinder. As a result, the power steering device having the function of correcting the cut-off delay can be configured compactly, and the mountability of the power steering device on the vehicle can be improved.

〔Example〕

FIG. 7 shows the overall structure of a power steering apparatus according to an embodiment of the present invention. The power steering apparatus includes a steering cylinder 10 that generates a steering force by hydraulic pressure. Steering cylinder 10
Has a cylindrical shape as shown in FIGS. 1 and 2, and a piston 11 shown in FIG. 7 is slidably held therein. A rack gear 12 is integrally connected to the piston 11 to form an integral type power steering cylinder. The rack gear 12 meshes with the sector gear 13.

As shown in FIG. 2, the sector gear 13 is fixed to a support shaft 14, and a pitman arm 15 is fixed to the support shaft 14. The pitman arm 15 is connected to a knuckle 17 via a drag link 16 shown in FIG. Therefore, by pulling the knuckle 17, it becomes possible to rotate the wheel 19 having the tire 18 mounted thereon around the kingpin 20 for steering.

A steering shaft having a steering wheel 22 attached to the tip of the steering cylinder 10 at the center thereof.
23 is designed to be inserted. An arm 24 is provided at the tip of the steering shaft 23 as shown in FIG. The tip of the arm 24 moves the spool 27 of the switching valve 26 via the pin 25. As shown in FIG. 2, the steering shaft 23 and the switching valve 26 are provided so that their axes are orthogonal to each other. In FIG. 7, the axis of the steering cylinder 10 and the switching valve 26 are arranged in parallel with each other, so that the arm 24 is cut off at its intermediate portion for the sake of convenience.

The switching valve 26 is an oil pump 28 and a check valve 29.
It is designed to be communicated via. When the spool 27 of the switching valve 26 is moved upward in FIG. 7, pressure oil is supplied to the chamber below the piston 11 of the cylinder 10 via the oil passage 30. At this time, the oil in the chamber above the piston 11 is returned to the reservoir 41 side via the return-side oil passage 31 and the switching valve 26. Further, when the spool 27 of the switching valve 26 is moved downward, pressure oil is supplied to the chamber above the piston 11 through the opening 32.

The switching valve 26 has a spool inside as shown in FIG.
The piston 27 is slidably held on both sides of the spool 27 while being slidably held, and is pressed by the spring 36 toward the pressure chambers 37, 38 on both sides. The left and right pressure chambers 37 and 38 are respectively shown in FIG. 7 and FIG.
It is connected to the pressure oil injection valves 39 and 40 shown in FIG. 4 and FIG. 4, and the hydraulic pressure is applied via these injection valves 39 and 40.

The left and right pressure oil injection valves 39, 40 are provided with a reservoir 41 shown in FIG.
And the return line 42, respectively. Then, solenoid valves 43 and 44 are respectively connected to these return pipes 42, and when the solenoid valves 43 and 44 are opened,
The spools of the pressure oil injection valves 39 and 40 are adapted to move upward in FIG. In addition, solenoid valves 43, 44
The opening and closing of the device is controlled by a controller 45 composed of a computer.

The pressure chambers 37, 38 on the left and right of the switching valve 26 are also connected by a communication pipe 46. A throttle valve 47 is connected to the communication pipe 46, and the throttle valve 47 is controlled by a stepping motor 48. The stepping motor 48 is also controlled by the controller 45. A vehicle speed sensor 49 and a steering force sensor 50 are connected to the input side of the controller 45. The steering force sensor 50 detects the relative movement of the double-structured steering wheel 22 with a strain gauge.

Furthermore, this power steering device is a sub cylinder 51.
The sub-cylinder 51 is used to correct the cut-off delay. Sub cylinder 51 piston
The upper and lower chambers of 52 are connected to the outlet side ports of the pressure oil injection valves 39 and 40, respectively. The piston 52 of the sub-cylinder 51 is connected to the pitman arm 15 via the link 53 and the pin 54.

With the above configuration, the steering wheel 22
When is operated, the steering force sensor 50 detects the steering force until the piston 11 of the steering cylinder 10 moves accordingly. Therefore, the controller 45 causes the pressure oil injection valves 39, 40
Operate. That is, by opening one of the solenoid valves 43 and 44, the corresponding pressure oil injection valve 39 or 40 is opened, and the pressure oil pressurized by the oil pump 28 is transferred to the sub cylinder 51.
Supply to the chamber above or below the piston 52.
Then, the piston 52 moves, and the pitman arm 15 is rotated via the link 53. This rotational movement is transmitted to the knuckle 17 via the drag link 16,
The wheel 19 equipped with 18 is steered without delay.

When the rotational movement of the steering wheel 22 is transmitted to the pin 25 of the switching valve 26 via the arm 24, the switching valve 26 moves to the left or right in FIG. Therefore, the oil pressurized by the oil pump 28 passes through the check valve 29 shown in FIG.
Alternatively, the gas is supplied from the opening 32 to the chamber below or above the piston 11.

Therefore, the piston 11 moves upward or downward in the cylinder 10. Due to the movement of the piston 11, the sector gear 13 is rotated via the rack 12, and the pitman arm 15 is rotated. Then, the turning motion of the pitman arm 15 is transmitted to the wheel 19 via the drag link 16 and the knuckle 17, and steering is performed. That is, after the steering by the sub-cylinder 51, the steering operation is performed by the steering cylinder 10 after the delay time of switching the switching valve 26 and rising of the hydraulic pressure in the cylinder 10 has elapsed.

At this time, pressure oil is supplied from the pressure oil injection valves 39 and 40 to the left and right pressure chambers 37 and 38 of the switching valve 26, respectively, so that resistance is provided when the spool 27 moves. I have to. Ie steering wheel
It is designed to generate resistance against the rotational movement of 22.
Moreover, depending on the vehicle speed detected by the vehicle speed sensor 49,
The left and right pressure oil injection valves 39, 40 are instructed by the controller 45.
Since the adjustment of the reaction force applied to the left and right pressure chambers 37, 38 is achieved by the duty control of the solenoid valves 43, 44, it is possible to generate the optimum resistance force according to the vehicle speed. . Further, the flow of oil between the left and right pressure chambers 37, 38 is allowed by the throttle valve 47, and the throttle is adjusted by the stepping motor 48.

As described above, the power steering device according to the present embodiment operates the correction of the steering delay of the steering cylinder 10 in association with the detection of the steering force sensor 50 by the sub cylinder 51 via the controller 45 and the pressure oil injection valves 39, 40. I am trying to do it. Therefore, the response time from when the driver operates the steering wheel 22 to when the steering is performed can be shortened, and the steering response at the time of high speed traveling is improved to provide a high margin type power steering device. It will be possible. In addition, the pressure chambers 37 on the left and right of the switching valve 26,
As described above, it becomes possible to supply the optimum pressure to the vehicle 38 through the controller 45, the solenoid valves 43 and 44, and the pressure oil injection valves 39 and 40 in accordance with the detection by the vehicle speed sensor 49 as described above. It is possible to achieve a power steering device.

In such a power steering device, a switching valve 26 for switching the supply of pressure oil to the steering cylinder 10, pressure oil injection valves 39, 40 for switching the supply of pressure oil to the sub-cylinder 51, and a pressure oil injection valve 39. , 40 to reservoir 41
Solenoid valves 43 and 44 for releasing oil to the first side respectively
As shown in FIGS. 6 to 6, the steering cylinder 10 is assembled. In particular, as shown in FIG. 1, the switching valve 26, the pressure oil injection valves 39 and 40, and the solenoid valves 43 and 44 are mounted on the outer peripheral portion of the steering cylinder 10. Moreover, the switching valve 26 is arranged so as to intersect the axis of the cylinder 10 at a right angle, and a pair of pressure oil injection valves 39 and 40 are mounted below the switching valve 26 in parallel with the cylinder 10.
Moreover, solenoid valves 43 and 44 are mounted below the injection valves 39 and 40 in parallel with the cylinder 10. Therefore, the control valves of the integral type power steering device, in particular, can be installed in a compact manner, thereby improving the mountability on the vehicle.

〔The invention's effect〕

As described above, according to the present invention, the steering force generated in the staying wheel is detected by the steering force sensor, and the pressure oil injection valve is switched in conjunction with the detection of the steering force sensor to supply the pressure oil to the sub-cylinder. In addition to compensating for the delay, a switching valve is arranged on the outside of the steering cylinder so that its axis intersects at a right angle, and a pressure oil injection valve is installed on the outside of the steering cylinder above or below the switching valve. Is mounted so that its axis is parallel to the steering cylinder. Therefore, according to such a configuration, it becomes possible to correct the turning delay by operating the sub-cylinder in conjunction with the detection of the steering force generated in the steering wheel,
It is possible to provide a power steering device with excellent responsiveness. Moreover, it becomes possible to compactly install the control valves of the power steering device, particularly the switching valve and the pressure oil injection valve, which are improved in responsiveness, on the outer portion of the steering cylinder. Therefore, it becomes possible to make the power steering device compact and improve its mountability on the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view showing a steering cylinder of a power steering apparatus according to an embodiment of the present invention, FIG. 2 is a lateral cross-sectional view of the same, and FIG. 3 is attached to the steering cylinder. FIG. 4 is a front view of the control valve, showing a part of the control valve, FIG. 4 is a front view of the control valve, FIG. 5 is a cross-sectional view showing the internal structure of the switching valve, and FIG. FIG. 7 is a bottom view of the valve, and FIG. 7 is a piping diagram showing the overall structure of the power steering device. The names of the main parts in the drawings are as follows. 10 …… Steering cylinder 15 …… Pitman arm 17 …… Knuckle 19 …… Wheel 22 …… Steering wheel 26 …… Switching valve 28 …… Oil pump 39 …… Pressure oil injection valve (left) 40 …… Pressure oil injection valve (Right) 43 …… Solenoid valve (Left) 44 …… Solenoid valve (Right) 45 …… Controller 49 …… Vehicle speed sensor 50 …… Steering force sensor 51 …… Sub cylinder

Claims (1)

[Claims] 1. A steering force sensor detects a steering force generated in a steering wheel in a device for steering a wheel by switching a switching valve by operating a steering wheel and supplying pressure oil from a pressure source to a steering cylinder. At the same time, the pressure oil injection valve is switched in association with the detection of the steering force sensor to supply pressure oil to the sub-cylinder to correct the cut-off delay, and the switching valve is provided on the outer side of the steering cylinder. The axes are arranged so as to intersect at a right angle, and the pressure oil injection valve is mounted on the outer side of the steering cylinder above or below the switching valve such that the axis is parallel to the steering cylinder. A power steering device characterized in that