JPH0288367A - Locking mechanism for main actuator - Google Patents

Abstract

PURPOSE:To make a locking mechanism compact and lightweight by providing a groove engaging a locking member at a neutral position and a cam for open ing a check valve in a receiving member connected to a tie rod, and connecting a hydraulic pressure source to an operating chamber of a release actuator through the check valve. CONSTITUTION:When a handle is steered from a neutral position to one side, a selector valve 33 is switched to open a valve plug 8 of a check valve 10 by means of pressurized oil of a hydraulic pump 32, and the pressurized oil is supplied through a passage 13 to a release actuator 2. A locking member 19 is then disengaged from a groove 18 of a receiving member 17 connected to a tie rod 15, so that the tie rod 15 can be reciprocated. When a steering angle of the handle exceeds a specified value, the tie rod 15 is forced to be moved, a cam 14 is disengaged from a stem 16 to close the passage 13, when the locking member 19 is locked in a released state, the receiving member 17 is returned to the neutral position, the passage is opened and operated to a locking position. Thus, simply by providing a cam on the receiving member 17, the locking mechanism can be made compact and lightweight as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a neutral lock mechanism applied to a rear wheel steering actuator of a four-wheel steering vehicle.

[Prior Art] As disclosed in Japanese Utility Model Application Publication No. 59-154455,
IQ of the main actuator that steers the rear wheels 1111 a
If the positioning fails, the main actuator is returned to the neutral position by the return spring and locked by the locking mechanism, locking the rear wheels in the straight-ahead position. This allows the vehicle to continue traveling by steering only the front wheels.

As shown in No. 2 @l, the main actuator 21 that steers the rear wheels has a cylinder 25 with a piston 26 in it, and an end chamber that accommodates a return spring 27, and both ends of the tie rod 15 connected to the piston 26 are It is connected to the rear wheel knuckle 40. In connection with the operation of the handle 39, the length is 1111.
When the first valve 35 is driven, pressure oil is supplied from the hydraulic pump 32 to one end chamber of the main actuator 21, and at the same time, oil in the other end chamber is returned to the oil tank 31. The tie rod 15 is pushed to the right or left together with the piston 26,
The rear wheels 41 are steered.

For example, the main actuator 21 is
When disabled, the force of the return spring 27 returns the piston 26 to the neutral position shown. At this time, the hydraulic pressure in the working chamber 5 of the unlocking actuator 2 is also released, so the locking member 19 is projected into the cylinder 25 together with the piston 4 by the force of the spring 6, and is engaged with the horizontal groove 23a of the tie rod 15. will be combined. As a result, the tie rod 15 is locked in the neutral position, and the rear wheel 41 is held in the straight-ahead position.

However, if the tie rod 15 is provided with the groove 23a, the strength will be impaired, which is not preferable.

As shown in FIG. 3, the cylindrical receiving member 22 fitted into the cylinder 25 is coupled to the tie rod 15 so as not to be able to move in the axial direction, and an annular vortex 23 with a horizontal cross section is provided on the receiving member 22.
By engaging the conical end of the locking member 19, the strength of the tie rod 15 is not impaired. However, if the axial dimension of the receiving member 22 is short, the following problem occurs when oil pressure failure occurs at the maximum steering angle position of the rear wheel 41. When the oil pressure fails, the locking member 19 immediately protrudes into the interior of the cylinder 25 and eventually hits the end of the receiving member 22, so that the locking member 19 prevents the receiving member 22 from returning. Although it is possible to make the dimensions of the receiving member 22 better than the stroke of the piston 26 of the main actuator 21, this is not preferable because the locking mechanism becomes long and heavy.

(Problem to be Solved by the Invention) In view of the above-mentioned problems, an object of the present invention is to provide a locking mechanism for a main actuator that is lightweight and does not reduce the strength of the tie rod.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention includes a groove that engages the locking member in the neutral position in the receiving member coupled to the tie rod, and a cam that pushes open the check valve. The hydraulic power source can be connected to the working chamber of the unlocking actuator that releases the locking member through the check valve.

[Function] The check valve 10 provided in the middle of the passage M13, 13a that connects the working chamber 5 of the unlocking actuator 2 to the hydraulic pump 32,
When the main actuator piston moves from its neutral position, it disengages and closes the cam 14, sealing the working chamber 5. Therefore, the locking member 1 of the unlocking actuator 2
is maintained in a retracted state from the cylinder 25.

When the tie rod 15 is returned to the neutral position by the force of the return spring when the oil pressure fails, the receiving member 17 returns without hitting the locking member 19, and the groove 18 of the receiving member 17 is inserted into the locking member 1.
approach almost the bottom of the At this time, the cam 1 of the receiving member 17
4 hits the stem 16 of the check valve 10 and pushes the stem 16 up against the force of the spring 9. The check valve 10 is opened and the oil in the working chamber 5 is returned to the oil tank 31. Unlocking 7 The locking member 19 is pushed down together with the piston 4 by the force of the spring 6 of the cutuator 2, and is engaged with the groove 18 of the receiving member 17, so that the tie rod 15 is locked in the neutral position.

[Embodiment of the Invention] As shown in FIG. 1, an unlocking actuator 2 coupled to a wall portion of a cylinder 25 (generally a fixed portion of a vehicle body) has a piston 4 fitted inside a cylinder 3. The working chamber 5 and the atmospheric chamber accommodating the spring 6 are partitioned. One locking member connected to the piston 4 passes through the wall and is projected into the interior of the cylinder 25. A sliding portion between the locking member 19 and the wall portion is fixed to the sealing member 20. The working chamber 5 is communicated with the inside of the housing 11 of the check valve 10 through a passage 13 made of a pipe, and is further connected to one of the hydraulic pump 32 and the oil tank 31 through a passage 13a provided in the wall of the cylinder 25 and a switching valve 33. It is possible to communicate with

The check valve 10 has a valve body 8 housed inside a housing 11 connected to a wall of a cylinder 25, and a valve seat 12 by a spring 9.
is urged to. The stem 16 of the valve body 8 is projected into the cylinder 25 .

A receiving member 17 coupled to the tie rod 15 is integrally provided with a groove 18 that can engage with a locking member 19 and a cam 14 that pushes up the stem 16. The other configurations are the same as in FIG. 2.

When the handle is turned from the neutral position to one side, the switching valve 3
3 is switched, and the pressure oil of the hydraulic pump 32 is switched to the switching valve 33,
The valve body 8 of the check valve 1o is pushed open through the passage 13a, and the liquid is supplied to the working chamber 5 of the unlocking actuator 2 through the passage 13. Therefore, the piston 4 is pushed up against the force of the spring 6, the locking member 19 is disengaged from the receiving member 17, and the tie rod 15 is enabled to reciprocate.

If the steering angle from the neutral position of the handle exceeds a predetermined value,
The servo control valve 35 is activated to form a hydraulic circuit for the main actuator that steers the rear wheels, and the tie rod 15 is pushed together with the piston. When the cam 14 is disengaged from the stem 16, the force of the spring 9 presses the valve body 8 against the valve seat 12, blocking the passage 13a and the passage 13, and locking the locking member 19 in the pulled up state. Next, the switching valve 33 is switched to the illustrated state.

Even if a hydraulic failure occurs during operation of the main actuator for steering the rear wheels, the check valve 10 remains closed and the piston 4 of the actuator 2 does not return.

When the piston of the main actuator is returned to the neutral position by the return spring, the receiving 8II material 17 of the tie rod 15 also returns to the neutral position. At this time, the cam 14 pushes up the stem 16, so the check valve 10 opens, and the oil in the opening chamber 5 of the unlocking actuator 2 flows through the passage 13, the check valve 10, the passage 13a,
The oil is returned to the oil tank 31 via the switching valve 33.

[Effects of the Invention] As described above, the present invention provides a receiving member connected to a tie rod with a groove that engages with a locking member at a neutral position and a cam that pushes open a check valve, and connects a hydraulic source to a check valve. The check valve locks the unlocking actuator in the released state while the main actuator is in operation, opens when the receiving member returns to the neutral position, and releases the locking member. Release the hydraulic pressure and move it to the lock position. Therefore, there is no need to provide a long receiving member on the tie rod, and it is only necessary to provide a cam that opens the check valve, so that a locking mechanism for the main actuator that is compact, lightweight, and reliable in operation is provided as a whole.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a locking mechanism of a main actuator according to the present invention, FIG. 2 is a side sectional view of a conventional locking mechanism, and FIG.
The figure is a side sectional view of another conventional locking mechanism. 2: Unlocking actuator 10: Check valve 14: Cam
15: Tie rod 17: Receiving member 18: Groove 19 Two locking member patent applicant Isuzu Automatic Co., Ltd.

Claims (1)

[Claims] A receiving member connected to the tie rod is provided with a groove that engages with the locking member at a neutral position and a cam that pushes open the check valve, and a hydraulic power source is passed through the check valve to the operating chamber of the unlocking actuator that releases the locking member. A locking mechanism for a main actuator, characterized in that it is connectable.