JPH0378482B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to improvements in proportional control valves.

(Prior art) Conventionally, as a proportional control valve, for example, the
As disclosed in Japanese Patent No. 125986, it is equipped with two proportional solenoids, a spool that moves left and right by the excitation force of the two proportional solenoids, and a sleeve in which the spool is slidably disposed, It is known that a cam or link that responds to the movement of the actuator is connected to the sleeve so that the position of the actuator is feedback-controlled to a position that corresponds to the amount of movement of the proportional solenoid.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional proportional control valve, if one or both proportional solenoids fail, the operation becomes impossible and feedback control of the actuator position and operation amount is disabled. There is a drawback that it will not be possible.

The present invention has been made in view of the above, and its purpose is to enable the proportional control valve to operate even when the proportional solenoid fails, and to ensure feedback control of the position and amount of operation of the actuator. It is in.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an auxiliary manual mechanism for manually operating the spool.

In other words, the specific solution of the present invention is a proportional control valve that feedback-controls the position and operation amount of the actuator as described above, that is, a proportional control valve that is provided at both ends of the valve body and receives a control signal that controls the movement of a controlled object. There are first and second proportional solenoids that operate, a pump port that is slidably fitted into the valve body and located at the center in the sliding direction, and a first and second proportional solenoid that is disposed on both sides of the pump port.
a sleeve having a cylinder port; the sleeve is slidably fitted into the sleeve and connected at both ends to each of the proportional solenoids, and is normally biased by a centering spring to connect the pump port to each cylinder port. While communication is cut off, when a control signal for the first or second proportional solenoid is received, the movement is controlled by the operation of the first or second proportional solenoid to connect the pump port and the first or second cylinder port. a spool connected to a controlled object and displaced by an amount corresponding to the amount of movement of the controlled object to move the sleeve in the same direction as the direction in which the spool is moved by the first or second proportional solenoid; It is assumed that the cylinder is equipped with a feedback link that blocks communication between the port and the first or second cylinder port. A protruding pin is arranged between the lands of the spool with a maximum travel distance between each land and the spool, and the protruding pin is provided eccentrically with respect to the fulcrum of the fitting member, and the fitting member is An auxiliary manual mechanism is constructed by providing an operation lever that is rotatably fitted into the valve body and rotates the fitting member about the fulcrum.

(Function) With the above configuration, in the present invention, for example, when the first proportional solenoid moves a predetermined amount due to input of a control signal, the spool also moves a predetermined amount in conjunction with the movement, so that the pump port is connected to the first cylinder port. As a result, hydraulic pressure is supplied to the controlled body and the controlled body operates. The motion of this controlled object is transmitted to the sleeve via the feedback link, and the sleeve moves in the same direction as the spool, so when the amount of movement of the sleeve reaches the amount of movement of the spool, the pump Communication between the port and the first cylinder port is cut off, and the operation of the controlled object stops at that point. Here, since the amount of movement of the controlled object is proportional to the amount of movement of the solenoid and spool, that is, the amount of movement of the first proportional solenoid, the amount of movement of the controlled object is feedback-controlled by the control signal value of the proportional solenoid. become.

In addition, even if the proportional solenoid is out of order, the operator can operate the operating lever of the auxiliary manual mechanism and rotate the fitting member to move the protruding pin in the spool's movement direction by the maximum amount of movement of the spool. By moving the spool by an appropriate amount exceeding , the spool can be moved by an appropriate amount using the protruding pin, so that feedback control of the amount of movement of the controlled body can be manually ensured.

(Effects of the Invention) As explained above, according to the proportional control valve of the present invention, the movement of the spool is controlled by a pair of proportional solenoids, and the movement of the sleeve is controlled by a feedback link connected to a controlled object. When performing feedback control of the amount of movement of the controlled object, even if the proportional solenoid is out of order, the auxiliary manual mechanism that moves the spool using a protruding pin allows the feedback control of the amount of movement of the controlled object to be performed manually. It produces the effect that can be secured.

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 and 2 show a proportional control valve according to the invention. In FIGS. 1 and 2, 1 is a valve body, and inside the valve body 1 is provided a first cavity 2 extending in the direction of its central axis (in the left-right direction in the figures). At both left and right ends of the valve body 1 in the figure, rods 3a are provided in the first space 2, respectively.
There are provided first and second proportional solenoids 3, 3' facing 3a'. Each of the proportional solenoids 3, 3' extends and operates the rods 3a, 3a' in response to a control signal for controlling the movement of a controlled object 12, which will be described later, and its operating characteristics are as shown in FIG. The force F for extending the rods 3a, 3a' increases in proportion to the increase in the control signal value i.

Further, a sleeve 4 is fitted into the first cavity 2 of the valve body 1 so as to be slidable in the left-right direction in the figure, and a spool 5 is fitted inside the sleeve 4 so as to be slidable in the left-right direction in the figure. They are movably fitted. A pump port 4a that communicates with the fluid pump 6 and a pump port 4a are provided at the center of the sleeve 4 in the sliding direction.
first and second cylinder ports 4b, 4b' located on both sides of the cylinder and communicating with the first and second cylinders 7, 7', respectively;
First and second tank ports 4c and 4c' are located on the opposite side of pump port 4b' and open to a tank (not shown), respectively. On the other hand, the left and right ends of the spool 5 are connected to the first and second proportional solenoid 3, respectively.
A pair of centering springs 8 are connected to the tips of the rods 3a, 3a' of the spool 5, and between the left and right ends of the spool 5 and the first and second proportional solenoids 3, 3'. , 8' are compressed to urge the spool 5 toward the center of the valve body 1.

One end of the sleeve 4 (the left end in the figure) faces a second cavity 9 formed in the radial direction of the valve body 1 and having a large opening at the lower part. A feedback link 10 is provided extending downward from the opening. As shown in FIG. 3, the feedback link 10 is supported so as to be rotatable in the left-right direction in FIG. The lower end of the feedback link 10 is connected via a connecting rod 11 to a controlled body 12 consisting of a swash plate of a variable displacement pump operated by the first and second cylinders 7 and 7'. has been done. Also,
The support hole 10a of the feedback link 10
An engagement pin 10b that protrudes to the right in FIG. 3 is provided below, and the other end of the sleeve 4 (the right end in FIG. A compressed positioning spring 13 is disposed, and the positioning spring 13 urges the sleeve 4 to the left in FIG. It is brought into abutment engagement with the engagement pin 10b of 1 through the buffer member 14. Therefore, when the controlled object 12 is controlled to be held in the upright state shown in FIG. Position by dowel pin 10b,
The sleeve 4 is positioned in the normal position shown in FIGS. 1 and 2, and in the normal position of the sleeve 4, the spool 5 is biased only by the centering springs 8, 8' and is in the neutral position shown. Sometimes, while the spool 5 blocks communication between the pump port 4a and each cylinder port 4b, 4b', the first proportional solenoid 3
When the rod 3a receives the control signal, the rod 3a
The spool 5 is moved from the neutral position to the first position by the extension movement of
After moving the spool 5 by a predetermined amount of play, the pump port 4a is moved to the right in the figure.
b and at the same time communicates with the second cylinder port 4.
b' is communicated with the first tank port 4c, while
When the second proportional solenoid 3' receives a control signal, the rod 3a' is extended to move the spool 5 from the neutral position to the left in FIG. It is configured to communicate the port 4a with the second cylinder port 4b' and at the same time communicate the first cylinder port 4b with the second tank port 4c'. Further, when the controlled body 12 rotates clockwise in FIG. 1 about its fulcrum 12a as the spool 5 moves to the right in FIG. Support hole 10
a) in the counterclockwise direction in FIG. 1, and move the sleeve 4 using the engagement pin 10b to the right in FIG. While communication with the first cylinder port 4b is cut off, when the controlled body 12 rotates counterclockwise in FIG. 1 as the spool 5 moves to the left in FIG. 10 clockwise in FIG. 1, the sleeve 4 is moved to the left in FIG. 1 by the biasing force of the positioning spring 13, and communication between the pump port 4a and the second cylinder port 4b' is cut off. It is configured.

As a feature of the present invention, the valve body 1 includes:
When the proportional solenoid 3, 3' is out of order, the spool 5
An auxiliary means mechanism 30 for manually controlling the movement of is provided (see FIG. 2). The auxiliary manual mechanism 30 is
A fitting member 3 rotatably fitted and supported by the valve body 1
1, an operating lever 32 that is pinned to the front end of the fitting member 31 and manually rotated about a fulcrum 32a as shown in FIG. It consists of a projecting pin 33 (see FIG. 3) which is implanted in the second cavity 9 and placed close to the spool 5 (see FIG. 3), and the fitting member 31 can be rotated by rotating the operating lever 32. By moving the protruding pin 33 in the left-right direction in FIG. 2, the protruding pin 33 is brought into abutting engagement with the spool 5, thereby controlling the movement of the spool 5 in the left-right direction in FIG. Furthermore, between the protruding pin 33 of the auxiliary manual mechanism 30 and the lands 5a and 5b of the spool 5 located on both sides of the protruding pin 33, there is a maximum movement amount of the spool 5 due to the operation of the proportional solenoids 3 and 3'. A gap of at least 3 mm (for example, 3 mm on each side) is provided to prevent the auxiliary manual mechanism 30 from being driven by the electrically controlled movement of the spool 5.

The fulcrum position adjustment mechanism 20 also includes a spool 5.
This device adjusts the neutral position (adjusts the amount of left and right play) with respect to the sleeve 4, and its configuration consists of a fitting member 21 that is rotatably fitted and supported on the valve body 1.
and an adjustment screw 22 provided at the front end of the fitting member 21, and the rear end of the fitting member 21 has a small diameter and is eccentric to the center as shown in FIG. The fulcrum position of the feedback link 10 can be adjusted (horizontal position adjustment) by rotating the fitting member 21 by rotating the adjustment screw 22 and moving the rear end in the left-right direction in FIG. ) and then move the sleeve 4 in the left-right direction in FIG. 2 to adjust the neutral position of the spool 5 (adjust the amount of play in the left and right directions).

Next, to explain the operation of the above embodiment,
When the controlled body 12 is in an upright position and both the first and second proportional solenoids 3, 3' are not receiving control signals, the spool 5 is biased by both centering springs 8, 8'. The sleeve 4 is positioned at the neutral position shown, the feedback link 10 is in a hanging state, and the positioning spring 13
Therefore, both cylinder ports 4b, 4b' are closed.

Now, for example, if a control signal is input to the first proportional solenoid 3, a force F 0 is generated in the first proportional solenoid 3 according to the control signal value (for example, io) based on the characteristics shown in Figure ₅ . Rod 3a
extends and moves to press the spool 5 to the right in FIG. Therefore, the spool 5 begins to move from the neutral position to the right in FIG.
b and at the same time communicates with the second cylinder port 4.
b' is communicated with the first tank port 4c, and while gradually opening the opening area of each cylinder port 4b, 4b', the pressing force _F0 of the rod 3a and the centering spring 8' on the right side of FIG. It stops at a position where the forces are in equilibrium. As a result, a flow rate corresponding to the opening area of the first cylinder port 4b is supplied from the fluid pump 6 to the first cylinder 7,
The controlled body 12 begins to rotate clockwise in FIG. 1 at a relatively high speed about its fulcrum 12a. When the feedback link 10 rotates counterclockwise in FIG. 1 about the fulcrum (support hole 10a) with the rotation of the controlled body 12, the engagement pin 10b moves rightward in FIG. As a result, the sleeve 4 moves to the right in FIG. 1 against the biasing force of the positioning spring 13, thereby reducing the opening area of the first and second cylinder ports 4b, 4b'. the result,
The flow rate to the first cylinder 7 gradually decreases, and the rotational speed of the controlled body 12 gradually slows down. When the controlled body 12 rotates until the amount of rightward movement of the sleeve 4 becomes equal to the rightward movement amount of the spool 5, the spool 5 is in a neutral position with respect to the sleeve 4. Communication between the pump port 4a and the first cylinder port 4b is cut off, and the controlled body 12 is controlled to be maintained at the inclination angle at that time. At this time, the inclination angle of the controlled body 12 is proportional to the amount of movement of the sleeve 4, in other words, the amount of movement of the spool 5, and this amount of movement is proportional to the rod pressing force F ₀ of the first proportional solenoid 3. As a result, the inclination angle of the controlled body 12 is the first as shown in FIG.
The angle is proportional to the control signal input to the proportional solenoid 3. Note that the portions indicated by X and X in FIG. 6 correspond to the amount of left and right play of the spool 5. Further, since the operation of the second proportional solenoid 3' upon receiving the control signal is the same as that described above, a description thereof will be omitted.

Here, since the movement of the spool 5 is directly controlled by the first and second proportional solenoids 3 and 3', its operation does not change even if dirt or the like adheres to it, and there is no need for strict control of dirt or the like. It can be done. In addition, two proportional solenoids 3,
Since only 3' is used, the servo valve can be provided at a lower cost than a conventional nozzle flapper mechanism. Moreover, the movement control of the spool 5 is directly controlled by the first and second proportional solenoids 3, 3', and the feedback control of the controlled body 12 is a mechanical feedback method via the feedback link 10. This makes it possible to make the servo valve highly responsive.

Moreover, if one or both of the proportional solenoids 3, 3' is out of order, the operator can rotate the operating lever 32 of the auxiliary manual mechanism 30 and rotate the fitting member 31 by an appropriate amount. Projecting pin 3
3 in the moving direction of the spool 5 (left and right direction in FIG. 2), and by an appropriate amount that exceeds the maximum movement of the spool 5 (for example, 3 mm on each side), the projecting pin 33 can be moved. Since the spool 5 can be moved by a desired amount in the left-right direction in FIG. 1, the inclination angle of the controlled object 12 can be manually feedback-controlled to the target angle.

[Brief explanation of drawings]

1 to 5 show embodiments of the present invention,
Fig. 1 is an overall configuration diagram for feedback control of the swash plate angle of a variable displacement pump, Fig. 2 is a partially cutaway plan view of the proportional control valve, and Fig. 3 is a sectional view taken along the - line in Fig. 1. , FIG. 4 is an enlarged front view of the auxiliary manual mechanism, FIG. 5 is a diagram showing the force generation characteristics of the proportional solenoid in response to the received control signal, and FIG. 6 is a diagram showing the tilt angle characteristics of the controlled object in response to the control signal. 1... Valve body, 3... First proportional solenoid,
3'...Second proportional solenoid, 4...Sleeve,
4a...Pump port, 4b...First cylinder port, 4b'...Second cylinder port, 5...
Spool, 8, 8'...centering spring,
10... Feedback link, 12... Controlled object, 31... Fitting member, 32... Operation lever, 3
2a...Fully point, 33...Protruding pin.

Claims (1)

[Claims] 1 First and second proportional solenoids 3 and 3', which are provided at both ends of the valve body 1 and are activated in response to a control signal to control the movement of the controlled object 12, are slidably fitted into the valve body 1. a sleeve 4 having a pump port 4a in the center in the sliding direction and first and second cylinder ports 4b, 4b' on both sides; connected to solenoids 3 and 3', respectively,
Normally, the communication between the pump port 4a and each cylinder port 4b, 4b' is interrupted by the centering springs 8, 8', while the control signal for the first or second proportional solenoid 3, 3' When receiving, the first or second proportional solenoid 3,
The movement of the pump port 4 is controlled by the operation of 3'.
a and the first or second cylinder port 4b, 4b', and a spool 5 that is connected to a controlled body 12 and is displaced by an amount corresponding to the amount of movement of the controlled body 12 to move the sleeve 4 into the Feedback that moves the spool 5 in the same direction as the moving direction of the spool 5 by the first or second proportional solenoid 3, 3' and blocks communication between the pump port 4a and the first or second cylinder port 4b, 4b'. a link 10 and a projecting pin 33 disposed between the lands 5a, 5b of the spool 5 with a maximum travel distance between the lands 5a, 5b and the spool 5; and the valve body 1.
The protruding pin 33 is rotatably fitted to the fulcrum 3.
Fitting member 31 provided eccentrically with respect to 2a
and an auxiliary manual mechanism 30 comprising an operating lever 32 that rotates the fitting member 31 about the fulcrum 32a.