JPH0288366A - Position control device - Google Patents

Abstract

PURPOSE:To obtain harmonious and smooth operation by inserting and connecting a parallel circuit consisting of a switch which detects shift of an input member to other position except a neutral position to be opened and a switch which detects a locking state to be opened to a conductive circuit of an electromagnetic opening/closing valve. CONSTITUTION:When an input member shifts from a neutral position, a switch 17 is operated to close an electromagnetic opening/closing valve 5 which releases a hydraulic control system, the hydraulic control system is switched to a controlled state, and a neutral locking mechanism 60 is simultaneously released. In conjunction with the action of an input rod 20 the hydraulic control system is operated to drive a main actuator 26. Adversely, when the input member is returned to the neutral position, the hydraulic control system is operated to first return the main actuator 26 to the neutral position, and a switch 27 is operated to maintain the hydraulic control system at a controlled state until the neutral locking mechanism 60 reaches a locking state, and thus, locking operation of the neutral looking mechanism 60 is performed moderately and smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a moving member such as a rod driven by a rear wheel steering actuator of a four-wheel steering vehicle.

[Prior Art] In a four-wheel steered vehicle, when the steering wheel turning angle is less than a predetermined value, it is preferable for the rear wheels to be held in a neutral position in order to obtain straight-line performance at high speeds. For this reason, by providing a play mechanism between the control valve that controls the hydraulic circuit of the main actuator that steers the rear wheels and the steering wheel shaft, and by providing a spring that biases the control valve toward the neutral position, the steering angle can be adjusted. A possible method is to set the control target position of the rear wheels to a neutral position and turn the main actuator to a neutral position when the value is below a predetermined value. However, with this method, when the rear wheel moves from the neutral position (straight-ahead position) due to an impact from the road surface, the result of this movement is fed back to one valve element of the control valve, and the other valve is held at the neutral position by a spring. Hydraulic pressure commensurate with the deviation from the element is supplied to the main actuator, and a force is applied to return the rear wheel to the neutral position, which operates to prevent the rear wheel from deviating significantly from the neutral position, which is the control target position. Therefore, it is difficult to completely suppress rear wheel fluctuation.

In order to reliably hold the rear wheels in the neutral position, it is preferable to provide a neutral locking mechanism that mechanically fixes the rear wheels in the neutral position without using feedback control. In a feedback control device that uses such a neutral locking mechanism in combination, the function of the feedback control device is wasted when the neutral locking mechanism is locked, resulting in a loss of control energy.
While the neutral locking mechanism is locking, it is efficient to interrupt or stop the feedback control t[l device.

However, if the feedback control device and the neutral locking mechanism are controlled based on the magnitude of the input signal, if the actual operation response to the operation command is poor, the feedback control device will stop before the neutral locking mechanism locks. Also, all of the feedback system m devices! There is a possibility that the neutral locking mechanism will be released before the Il operation.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the purpose of the present invention is to solve the problem without contradiction in operation,
Feedback system within the range where the neutral locking mechanism is released!
11] To provide a position control device that allows the device to move smoothly.

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention includes a switch that detects the transition of the input member from the neutral position to a position other than the neutral position and opens the switch, and a locking state of the neutral locking mechanism. A parallel circuit with a switch that detects and opens is inserted and connected to four circuits of an electromagnetic on-off valve that releases the hydraulic III system of the main actuator that controls the position of the operating member to the oil tank.

[Function] In a range where the steering angle is small, the position of the input rod 20 corresponding to the amount of operation of the handle 43 is near neutral, so the ball 22 provided on the push piece 20a is returned to the neutral position by the neutral return spring 21. It is located near the center of the cam member 23 held by the switch 1 and falls into the groove 23a.
7.18 is opened by spring 19. switch 18
When opened, the electromagnetic switching valve 4 is demagnetized and the pipe 57 is communicated with the oil tank 3, so the working chamber 11 of the locking actuator 28 of the neutral locking mechanism 60 is released to the oil tank 3, and the spring 33 locks the piston. 30 and a locking member 31 is engaged in the receiving member 32, and the piston 2 of the main actuator 26
4 and tie rod 15 are anchored at the neutral position.

When the steering wheel turning angle is small and the neutral locking mechanism 60 is in the locked state, the switch 17.27 is opened and the electromagnetic on-off valve 5 is opened.
Since the pipes 51 and 52 communicate with each other, the pressure oil from the hydraulic pump 2 is directly returned to the oil tank 3, and the hydraulic pressure t8111 system is brought to a rest state.

When the cutting angle of the handle 43 increases, the input rod 20 interlocking with the handle 43 moves in the axial direction, and the ball 22 of the pusher piece 20a of the input rod 20 rides on the groove 23a.

The switch 17 is closed, the m1ll on-off valve 5 is energized, and...
Between the tubes 51 and 52 is il! 1Fi, the pressure oil from the hydraulic pump 2 is sent to the differential h+tm valve 6, and the hydraulic control system enters the control state. However, unless the pushing piece 20a comes into contact with the protruding piece 23b of the cam member 23, the cam member 23 is held at the neutral position by the neutral return spring 21, the valve body 8 of the differential control valve 6 is at the neutral position, and the main A hydraulic circuit for driving the piston 24 of the actuator 26 is not formed.

When switch 17 is pressed, simultaneously (or with a slight delay)
The switch 18 is closed and the electromagnetic switching valve 4 is energized. Pressure oil from the hydraulic pump 2 is sent to the working chamber 11 of the locking actuator 28 through the pipe 57, the piston 30 is pushed up against the force of the spring 33, and the locking member 31 is moved up to the receiving member 32.
The neutral locking mechanism 60 is released. At this time, switch 27 is closed, but since switch 17 is already closed, 1! There is no change in the operation of the magnetic on-off valve 5.

When the neutral locking mechanism 60 is released and the impact from the road surface is transmitted to the rear wheel and the tie rod 15 is pushed, the gentle movement of the tie rod 15 causes the rack 10.108. The misalignment between the cam member 23 and the tie rod 15, which is transmitted to the differential mechanism including the pinion 12 and held in the neutral position by the neutral return spring 21, is transmitted to the valve body 8 of the differential control valve 6, and the hydraulic pressure is Pressure oil from the pump 2 is sent to the pipe 53 or 54, creating a force that returns the piston 24 connecting the tie rod 15 of the main actuator 26 to the neutral position, thereby preventing the rear wheel from moving significantly from the neutral position.

When the steering angle exceeds a predetermined value, the pushing piece 20a hits the protruding piece 23b, and the cam member 23 is pushed in the axial direction against the force of the neutral return spring 21. This movement is transmitted to the valve body 8 of the differential control valve 6 via the differential am, and the main actuator 26
is driven. When the tie rod 15 is driven by the main actuator 26, this movement passes through the differential mechanism to the valve body 8.
act to return it to the neutral position. When the tie rod 15 moves to a position corresponding to the position of the cam member 23, the valve body 8 becomes the neutral position, the movement of the main actuator 26 is stopped, and the rear wheel steering angle is maintained at that position.

When the handle 43 is returned to the neutral position, the cam member 23 is pushed by the force of the neutral return spring 21 following the push piece 20a,
The valve body 8 moves in the opposite direction and the main actuator 26 returns to the neutral position. That is, the main actuator 26 returns to the neutral position before the handle 43 completely returns to the neutral position.

In the process of the ball 22 of the push piece 20a falling into the groove 238, the switch 18 opens, the electromagnetic switching valve 4 switches, the hydraulic pressure of the locking actuator 28 is released, and the force of the spring 33 causes the locking member 31 to move into the receiving member. 32.

When the return operation of the handle 43 is quick and the switch 17 is opened at the same time as the switch 18 is opened, even if the locking operation of the neutral locking mechanism 6o is incomplete, the switch 27 remains closed. There is no change in the operating status of 5. Therefore, the hydraulic system l1lIIIl is in a controlled state and maintains the function of preventing the tie rod 15 from being significantly displaced from the neutral position due to impact from the road surface.

When the neutral locking mechanism 60 is in the locked state, the switch 27 is opened, and since the switch 17 is also already open, the electromagnetic on-off valve 5 is demagnetized, the pipes 51 and 52 are communicated, and the hydraulic pressure I
The III system becomes dormant. At this time, from the road! [
1 acts on the rear wheel, the neutral locking mechanism 60 prevents movement of the tie rod 15.

E Example of the Invention] FIG. 2 is a schematic configuration diagram of a four-wheel steering system equipped with a position control device according to the present invention.
4, steering angle lllll11 mechanism 14, differential 11Jtll
1 valve 6, a main actuator 26 for steering the rear wheels, and a neutral locking mechanism 60. When the front wheel steering mechanism 34 rotates the steering shaft 44 to the right using the handle 43, for example,
The output shaft 35 is rotated, the drag link 38 is pulled forward by @37 of the output shaft 35, the front wheel knuckle 4o is rotated clockwise around the vertical support shaft 39, and the front wheel 41 is deflected to the right. Ru. The left and right front wheel knuckles 40 are interlocked and connected by a tie rod 45.

The steering angle control l1 mechanism 14 is connected to the output shaft 35 of the front wheel steering mechanism 34.
136 to the axis 47 by the link 42! '! 46. By screwing the threaded shaft portion of the shaft 47 into the threaded hole of the input rod 20, rotation of the shaft 47 is converted into axial movement of the input rod 20. On the other hand, the amount of movement of the tie rod 15 is transmitted to the rack of the steering angle control mechanism 14 by the transmission cable 15a connected to the tie rod 15. The differential 1iIJ is related to the difference between the axis movement amount of input lot 20 and the rack movement amount.
T! The rod 9 protruding from the valve body 8 of the II valve 6 is axially moved.

The differential control valve 6 is a directional switching valve with a neutral position open type, and the pressure oil of the hydraulic pump 2 is controlled by the differential control valve 6. ! 52 to one of the pipes 53 and 54, and the oil in the other pipe is returned to the oil tank 3 via the pipe 51.

The tubes 53, 54 are each connected separately to the end chambers of the main actuator 26.

The main actuator 26 includes a cylinder 25 fitted with a piston 24, and a tie rod 15 connected to the piston 24.
Both ends of the rear wheel knuckle 48 are connected to the rear wheel knuckle 48. A rear wheel knuckle 48 that supports the rear wheel 50 is rotatably supported by the vehicle body by a vertical support shaft 49. When the handle 43 is in the neutral position, the piston 24 is returned to the neutral position by return springs housed in each end chamber.

In the neutral locking mechanism 60, the horizontal locking member 31 can be engaged with the conical groove of the receiving member 32 coupled to the tie rod 15 by the locking actuator 28. The locking actuator 28 has a piston 30 fitted inside the cylinder 29.
, an atmospheric chamber housing the spring 33 and an operating chamber are separated. A pipe 57 connected to the working chamber is connected to a pipe 55 connected to the hydraulic pump 2 and a pipe 56 connected to the oil tank 3 by means of the electromagnetic switching valve 4.
It is possible to communicate with one of the two.

As shown in FIG. 1, the neutral locking mechanism 60 according to the present invention is released before the main actuator 26 is actuated, and conversely is locked after the main actuator 26 returns to the neutral position.
The differential control valve 6 is then disconnected from the hydraulic pump 2.

Therefore, the electromagnetic on-off valve 5 is connected between the pipe 52 and the pipe 51. A rod 22a biased by a spring 19 and a ball 22 projected outward by the rod 22a are housed in a cylindrical portion formed in the input rod 20. A switch 17.18 is supported on the rod 22a. A groove 23a is provided in the center of the cam member 23 to engage the ball 22 in the neutral position of the handle 43.
However, a pair of protrusions 23b are formed on both sides of the groove 23a with a predetermined distance S between them.

The rack 10 integrated with the cam member 23 is engaged with the pinion 12. The pinion 12 is connected to the differential control valve 6 by the shaft 13.
It is supported by a rod 9 connected to a valve body (spool) 8. Binion 12, tie rod 15 and transmission cable i5a
The locks 10a, which are connected so as to move integrally, are engaged with each other. In order to bias the cam member 23 to the neutral position,
A neutral return spring 21 is interposed between the fixed member 61 and the cam member 23.

A switch 27 is supported on the outer end of a rod 30a connected to a piston 30 of lock actuator 28. 'R
A switch 18 is connected to a current supply circuit from the source battery 16 to the electromagnetic switching valve 4 . A parallel circuit consisting of a switch 17 and a switch 27 is inserted and connected to the current supply circuit from the power source battery 16 to the electromagnetic on-off valve 5 .

Next, the operation of the position control device according to the present invention will be explained. When the handle 43 is in the neutral position, the input rod 20
The ball 22 supported by the cam member 23 is engaged with the groove 23a of the cam member 23. The cam member 23 is brought into the illustrated state relative to the fixing member 61 by the force of the neutral return spring 21. Solenoid switching valve 4
communicates the working chamber 11 of the locking actuator 28 with the oil tank 3, and the 1ttan leap valve 5 communicates the discharge port of the hydraulic pump 2 with the oil tank 3. The main actuator 26 is returned to the neutral position, the locking member 31 is engaged with the receiving member 32 of the tie rod 15 by the force of the spring 33, and the rear wheel 50 is fixed at the neutral position (straight ahead position).

Now, if you turn the steering wheel 43 to the right, for example, the output shaft 35 of the front wheel steering mechanism 34! 36 and 37 are rotated, the drag link 38 is pulled forward, and the front wheel knuckle 40 is attached to the support shaft 3.
It rotates clockwise about 9, and the front wheel 41 is deflected to the right. At the same time, link 42 is pulled forward and shaft 47
The input rod 20 moves to the right due to the relative screw movement between the input rod 20 and the input rod 20 .

When the ball 22 runs over the full height 238, the switch 17 closes, and electricity is supplied from the power source battery 16 to the electromagnetic on-off valve 5 via the switch 17, cutting off between the pipes 51 and 52, and reducing the hydraulic pressure 1.
1 Enters JIO state. At the same time (or with a slight delay), the switch 18 closes, the electromagnetic switching valve 4 switches, and the pressure oil from the hydraulic pump 2 is supplied to the working chamber 11 of the locking actuator 28 via the pipe 55, the electromagnetic switching valve 4, and the pipe 57. Ru. The piston 30 moves upward against the force of the spring 33, the locking member 31 separates from the receiving member 32, and the neutral locking device l1lI60
is canceled. At the same time, switch 27 closes.

When the input lot 20 moves further to the right, the push piece 20a
hits the protruding piece 23b, and the cam member 23 is pushed to the right.

The binion 12 is rotated by the rack 10 and moved to the right. The valve body 8 moves to the right together with the rod 9, and the pressure oil of the hydraulic pump 2 flows through the pipe 52, the differential υJwJ valve 6,
The oil in the right end chamber of the main actuator 26 enters the right end chamber through the pipe 54, and the oil in the left end chamber is returned to the oil tank 3 through the pipe 53, the differential IIIWJ valve 6, and the pipe 51.

The tie rod 15 moves to the left together with the piston 24,
The rear wheel derailleur 48 rotates counterclockwise around the support shaft 49 (
(Fig. 2), and the rear wheel 50 is rotated to the left (opposite phase to the front wheel).
deflected to Rack 1 that moves integrally with tie rod 15
Due to the leftward movement of 0a, the rod 9 is moved through the pinion 12.
At the same time, the valve body 8 is returned to the left, and eventually the valve body 8 is returned to the neutral position. In this way, when the operation of the main 7 cutuator 26 corresponding to the steering angle is completed, the differential control valve 6
The valve body 8 returns to the neutral position, and the rear wheel 50 is held at that steering angle.

When the handle 43 is returned to the neutral position (straight ahead position), the input rod 20 moves to the left, and in accordance with this, the cam member 23 moves to the left by the force of the neutral return spring 21. Ball 2
2 falls into the groove 23a, the cam member 23 returns to the neutral position shown. During this time, the valve body 8 moves to the left, and the pressure oil of the hydraulic pump 2 flows through the pipe 52.
The lllll valve 6, '1153' is supplied to the left end chamber of the 17'y tube 26, the tie rod 15 moves to the right together with the piston 24, and eventually the tie rod 15 and the valve body 8 are returned to the neutral position.

Finally, when the ball 22 falls to the full position 23a, the switch 17.
18 is opened, and the electromagnetic switching valve 4 is switched to the illustrated position.

Therefore, the construction of the locking actuator 28] Chamber 11
The hydraulic pressure is released, the locking member 31 is engaged with the receiving member 32/\ by the force of the spring 33, and the tie rod 15 of the main actuator 26 is locked in the neutral position. At this time, switch 27 is opened.

1! The magnetic closure valve 5 is returned to the illustrated position. In this state, even if the valve body 8 of the outside control valve 6 operates, the main actuator 1-2
6 does not work.

It is clear from the above that J: sea urchin, the push piece 20a is the protrusion piece 2.
3b (displacement amount with an interval of 5 minutes), the differential l1IlIIl valve 6 does not operate even if the steering wheel is turned, and the rear wheels are not steered. When the steering wheel turning angle exceeds an amount corresponding to the displacement amount of the interval of 5 minutes, the rear wheel steering angle increases in proportion to the front wheel steering angle, as shown in FIG. Here, the pusher piece 20a and the protrusion piece 23
If the configuration is such that the distance S from the steering wheel increases in proportion to the vehicle speed, the steering angle from the neutral position of the steering wheel or the front wheel steering angle (dead zone ) increases, and as the vehicle speed increases, the ratio of the steering angle of the rear wheels to the front wheels becomes smaller, and four-wheel steering suitable for actual driving conditions is achieved.

In the above embodiment, a rack-binion type differential mechanism and a shaft-moving type actuation control valve were used, but the same effect can be obtained by using a rotational phase type differential control valve (rotary control valve). can get.

[Effects of the Invention] As described above, the present invention provides a parallel circuit of a switch that opens upon detecting the transition of the input member from the neutral position to a position other than the neutral position, and a switch that opens upon detecting the locked state of the neutral locking mechanism. is inserted and connected to the energizing circuit of the electromagnetic on-off valve that releases the hydraulic control system of the main actuator, which changes the position of the operating member, to the oil tank, so when the input member moves from the neutral position, the former switch operates to adjust the hydraulic pressure tIIIll. The electromagnetic on-off valve that releases the system closes, the hydraulic control system switches to the controlled state, and at the same time the neutral locking mechanism is released. A hydraulic control system operates in conjunction with the movement of the input rod to drive the main actuator. Conversely, when the input member returns to the neutral position, the main actuator is returned to the neutral position first by the action of the hydraulic control system, but the latter switch operates until the neutral locking mechanism becomes locked, and the hydraulic control system Since the control system is maintained in a controlled state, the locking operation of the neutral locking mechanism is natural and smooth.

In addition, due to the action of the switch that opens when the neutral locking mechanism is in the locked state, the hydraulic control system is released and the hydraulic control system is stopped only when safety is ensured by the neutral locking l11411I, so the control energy is Losses are safely reduced.

[Brief explanation of drawings]

Fig. 1 is an electric/hydraulic circuit diagram of the position control w device according to the present invention, and Fig. 2 is a four-wheel steering system equipped with the same level II III ml device! The configuration diagram of i11, FIG. 3, is a miniature diagram illustrating the operation of the steering angle IIIO mechanism. 5: Solenoid on/off valve 6: Differential 111J control valve 14: Rudder angle control 11 units $1 17.27: Switch 20: Input lot 21: Neutral return spring 26: Main actuator 6
0: Neutral locking mechanism patent applicant Isuzu Motors Co., Ltd.

Claims (1)

[Claims] The hydraulic pressure of the main actuator that controls the position of the operating member is connected to a parallel circuit of a switch that opens when it detects the transition of the input member from the neutral position to a position other than the neutral position and a switch that opens when it detects the locked state of the neutral locking mechanism. A position control device characterized by being inserted and connected to the energizing circuit of an electromagnetic on-off valve that releases the control system to an oil tank.