JPH0245573Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field This invention includes a pressure reducing valve driven by a solenoid, and uses hydraulic pressure supplied through the pressure reducing valve to move the piston of an actuator in accordance with the input voltage or current to the solenoid. The present invention relates to a driving electrohydraulic actuator.

BACKGROUND ART In recent years, there has been a strong demand for energy saving in mechanical devices through hydraulic control, and in particular, it is desired to significantly reduce the power consumption of solenoid valves, which are most commonly used in hydraulic systems.

For this reason, various pilot-driven solenoid valves have been developed.

FIG. 1 shows an example of a conventional electrohydraulic actuator used for analog pilot driving of a main valve such as a directional control valve.

This electrohydraulic actuator includes a pressure reducing valve component 1, a pilot body 3 that incorporates a piston 20, a return spring 21, etc. of an actuator 2 that is operated by hydraulic pressure supplied through the component part 1;
It consists of a solenoid component 4 for driving the pressure reducing valve 1, and can be represented by a hydraulic symbol as shown in FIG.

Then, the solenoid component 4 includes a housing 4
Solenoid coil 4 wound around bobbin 41 within 0
2, a fixed iron core 44 fixed to a cylindrical core tube 43, and a movable piece 45 made of a magnetic material installed inside the core tube 43 so as to be able to slide slightly, and fixed to the movable piece 45. push pin 46
is slidably passed through the fixed iron core 44.

Solenoid coil 4 of this solenoid component 4
2, when the fixed iron core 44 and the movable piece 45 are excited and attracted to each other, the movable piece 45 moves to the right with the push pin 46, thereby opening the spool 10 of the pressure reducing valve component 1 in the pilot body 3. It is moved to the right against the spring 12, and part of the pilot oil pressure from the P port is released to the tank from the T port, and the output oil pressure from the C port (proportional to the input voltage or current to the solenoid coil 42) is transferred to the oil pressure. act on the actuator 2 through the path 3a,
The piston 20 is moved to the right to drive the main valve 5.

At this time, the oil pressure at the C port is fed back to the spring chamber 11 through the orifice 13, and the spool 10 is balanced at a position where the output oil pressure is proportional to the input voltage or current value to the solenoid coil 42.

However, in such conventional electrohydraulic actuators, although the pressure reducing valve component 1 and the actuator 2 are built into the pilot body 3 in order to reduce the size, the solenoid component 4
Since the pilot body 3 was provided separately, there was a limit to miniaturization.

Further, since the output hydraulic pressure of the pressure reducing valve component 1 is applied to the actuator 2 through the oil passage 3a, the response becomes slow, which poses a problem in achieving high speed control.

Purpose This invention was made in view of the above points, and the purpose is to provide an electrohydraulic actuator for analog operation that can be ultra-miniaturized, has a quick response, and has a large operating force.

Structure Therefore, the electrohydraulic actuator according to this invention includes a valve body driven by a movable piece, a fixed part that forms an oil passage for each port, and an orifice for output hydraulic feedback, in the fixed iron core of the solenoid component. The pressure reducing valve component and the piston of the actuator are housed and provided, and the output hydraulic pressure of the pressure reducing valve component is applied directly to the piston.

Embodiment Hereinafter, an embodiment of this invention will be described with reference to FIG. 3. Parts corresponding to those in FIG.

A large diameter hollow part 44a and a small diameter hollow part 44b following the large diameter hollow part 44a are provided in the fixed core 44 of the solenoid component 4, and the pressure reducing valve component 1 and the actuator 2 are housed therein.

The pressure reducing valve component 1 consists of a spool 10 which is a valve body and a fixed part 14, and the fixed part 14 has a large diameter hollow part 44.
It is inserted into a.

This fixing part 14 has a cylindrical shape with the right end closed,
The spool 10 is slidably fitted, and the oil passage of the P port to which pilot oil is supplied, the oil passage of the T port connected to the tank, the oil passage of the C port directly connected to the actuator 2, and the orifice 1 are inserted.
3 are formed respectively. The P port and the T port are oil passages 44 formed in the fixed iron core 44, respectively.
c, 44d, and the oil passage of the C port also communicates with the spring chamber 11 via the orifice 13.

The spool 10 has a spring chamber 1 of the fixed part 14.
1 is provided with a leftward movement by a spring 12, and the left end portion in the figure is fixed to a movable piece 45 through a small diameter hollow portion 44b of a fixed iron core 44.

The spool 10 also has an oil passage 10a that connects the small diameter hollow part 44b of the fixed iron core 44 and the T port along the central axis and also communicates with the C port.
The width of the land portion 10b is equal to that of the fixed portion 1.
The width of the groove 14a of the C port is made smaller than the width of the groove 14a of the C port formed in 4.

On the other hand, adjacent to the fixed part 14, the piston 20 of the actuator 2 is inserted into the large diameter hollow part 4 of the fixed core 44.
4a so as to be slidably inserted into the stop spring 22.
The return spring 21 engaged between the fixing portion 14 and the fixing portion 14 is biased toward the fixing portion 14 . However, if a spring for returning the piston 20 is provided on the load side, this return spring 21 is not necessary.

At the left end in the diagram of the solenoid component 4, there is a small diameter portion 43 formed with a female thread on the inner periphery of the core tube 43.
An adjustment screw 48 passing through a manual lever rod 47 is screwed into a and fixed with a nut 49.

Between the inner end surface of the manual lever rod 47 and the groove formed on the left end surface of the movable piece 45,
A spring 60 stronger than the spring 12 is interposed.

Further, on the outer periphery of the movable piece 45, there is a groove 4 through which oil flows.
5a is provided to reduce resistance during movement. 61 and 62 are O-rings for sealing.

Note that 63 is a flange plate, and 64 is a bolt, by which this electrohydraulic actuator is fixed to the main body 50 of the main valve 5.

Next, the operation of this embodiment will be explained.

When the solenoid coil 42 is not energized,
Since the spool 10 is moved to the left by the force of the spring 12 and is in the state shown in FIG.
It communicates with the T port through 0a.

When the solenoid coil 42 is energized and excited,
Since the fixed core 44 and the movable piece 45 attract each other, the movable piece 45 moves to the right, pushing the spool 10 and causing it to slide to the right against the spring 12.

As a result, the land portion 10b also moves to the right, so that the P port and the C port communicate with each other, and the flow path between the C port and the T port is narrowed. Therefore, the pilot oil pressure from the P port is slightly reduced and output to the C port, and acts directly on the actuator 2, and the oil pressure pushes the piston 20 to the right in the figure against the return spring 21.

The operating force of the piston 20 drives the valve body in the main valve 5 to control the flow rate of the main circuit.

At that time, the hydraulic pressure of the C port also acts on the spring chamber 11 via the orifice 13, and the spool 10
It has a feedback effect that tries to push back to the left.

Now, the final displacements of the spool 10 and the piston 20 are x and X, respectively, the output oil pressure of the C port is Pc, and the input voltage of the solenoid coil 42 is V,
If the input current is i, then X= _K1・x= _K2・Pc= _K3・i (however, _K1 , _K2 , and _K3 are constants).

That is, the piston 20 is connected to the solenoid coil 4
2 or a stroke proportional to the input voltage, analog control can be performed.

After that, when the solenoid coil 42 is de-energized, the attractive force between the movable piece 45 and the fixed core 44 disappears, so that the spool 10
The return force causes the movable piece 45 to move to the left and push the movable piece 45 back away from the fixed core 44.

The spool 10 blocks the P port and provides wide communication between the C port and the T port.

As a result, the oil in the actuator 2 flows out from the C port to the tank through the oil passage 10a in the spool 10 and the T port, so the piston 20 moves to the left by the biasing force of the return spring 21 and returns to FIG. Return to the state shown.

Note that it is desirable to use a non-magnetic material for the spool 10 and the fixing part 14 to prevent adverse effects due to adhesion of foreign matter contained in the oil, iron powder, etc.

When using this electrohydraulic actuator for on/off operation, when energizing the solenoid coil 42 of the solenoid component 4, apply enough voltage to sufficiently displace the spool 10 of the pressure reducing valve component 1. good.

For manual control, screw in the adjustment screw 48 and push the movable piece 45 to the right in the figure via the spring 60, thereby displacing the spool 10. Piston 20 can be actuated in the same way. This adjustment screw 48 is normally used for zero adjustment of the spool 10.

Furthermore, if the on/off operation is to be performed manually, the manual push pin 47 may be strongly pushed in or released.

Effects As is clear from the above explanation, the electrohydraulic actuator of this invention eliminates the push pin that was provided in the conventional solenoid component to push the valve body of the pressure reducing valve, and the pressure reducing valve is constructed in that space. Because the unit and actuator were stored, the first
The pilot body in the conventional example shown in the figure is no longer necessary, making it possible to significantly reduce the size of the entire system, and since the output hydraulic pressure of the pressure reducing valve component is directly applied to the piston of the actuator, the response is also faster.

This electrohydraulic actuator can obtain a large operating force, so it can be used as a simple actuator for various analog operations.
It can be used for electromagnetic driving of relief valves, flow control valves, etc. that require a large operating force that cannot be handled by normal direct-acting proportional solenoid valves.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing an example of a conventional electromagnetic actuator for analog operation, Fig. 2 is a hydraulic symbol diagram thereof, and Fig. 3 is a longitudinal cross-sectional view of an electromagnetic hydraulic actuator showing an embodiment of this invention. It is a diagram. 1... Pressure reducing valve component, 2... Actuator,
4... Solenoid component, 5... Main valve, 10...
Spool (valve body), 13... Orifice, 14...
... Fixed part, 21 ... Return spring, 42 ... Solenoid coil, 43 ... Core tube, 44 ...
...Fixed core, 45...Movable piece.

Claims (1)

[Scope of utility model registration request] comprising a pressure reducing valve driven by a solenoid;
In an electrohydraulic actuator that drives a piston of an actuator by hydraulic pressure supplied through the pressure reducing valve, a fixed iron core is fixed to a core tube that is covered with a solenoid coil, and a movable piece of magnetic material is installed inside so as to be able to slide slightly. A pressure reducing valve component comprising a valve body driven by the movable piece and a fixed part forming an oil passage for each port and an orifice for output hydraulic pressure feedback, in the fixed core of the solenoid component, and the actuator. An electrohydraulic actuator, characterized in that the piston is housed therein, and the output hydraulic pressure of the pressure reducing valve component is applied directly to the piston.