JPH0133715B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic control valve, and more particularly to a multistage electromagnetic control valve in which a valve element can be positioned stepwise at a plurality of positions on one side of a normal position.

A type of electromagnetic control valve is an electromagnetic drive device that includes a movable iron core and a solenoid, in which a valve element that is slidably fitted in the axial direction into a valve body that has multiple ports is always held in its normal position by a spring. The plurality of ports are moved from their normal positions against the restraining force of the spring, and the plurality of ports are brought into communication.
That is, there are valves that change the communication direction or communication area, and are used as directional switching valves, throttle valves, on-off valves, etc. For example, in directional control valves, a spool is used as a valve element, and depending on the number of alternative positions of the spool, these are referred to as three-position control valves and two-position control valves. A three-position switching valve is provided in the valve body, with the spool normally held in the neutral position by a spring, and moved to either side of the neutral position by energizing one of the solenoids on both sides. In a two-position switching valve, the spool is held in one side by a spring, and moved to the other side when the solenoid is energized. It is used to switch the communication status of a plurality of ports. In addition, in throttle valves and on-off valves, the valve element, which is normally held at the normal position by a spring, is moved by the excitation of a solenoid, and the flow area of the fluid passage can be changed in stages, or the valve element can be moved in a normal position by a spring. It opens and closes.

Conventionally, in this type of electromagnetic control valve, the valve element can be positioned at one predetermined position on one side of the normal position by energizing a solenoid. Of course, some manually operated directional control valves, such as a 5-position control valve, in which the spool can be positioned at two positions on one side of the normal position, are known, but such valves are not known for electromagnetic control valves. It wasn't. Also,
Some electromagnetic control valves are known, such as proportional control valves, in which the valve element can be positioned at any position within a certain range, but the control circuit for controlling its operation is complex, and such If a control valve is used, the hydraulic circuit, pneumatic circuit, etc. have to be expensive.

The present invention has been made against the background of the above-mentioned circumstances, and aims to provide a multi-stage electromagnetic control valve that can stepwise position a valve element to two or more positions on one side of the normal position.

To achieve this objective, the multistage electromagnetic control valve according to the present invention includes (a) a valve body having a plurality of ports;
(b) a valve element that is fitted into the valve body and moves in the axial direction to change the communication state between the plurality of ports; (c) a first spring that always holds the valve element in the normal position; d) a movable iron core disposed in series with the valve element and moving in the axial direction to push the valve element in the axial direction against the elastic force of the first spring; and (e) a solenoid provided with the movable iron core. (f) an electric circuit that applies different operating forces in at least two stages: a first operating force that is large enough to overcome the elastic force of the first spring; and a second operating force that is larger than the first operating force; While the movable iron core moves a certain distance in the direction of pushing the valve, it remains stationary at the original position, and while the movable iron core moves beyond the certain distance, it moves from the original position together with the movable iron core. (g) moving the plunger with a force greater than said first actuation force minus the elastic force of the first spring and less than said second actuation force minus the elastic force of the first spring; a second spring held in the original position by an elastic force; and (h) the fixed distance is changed by changing the relative position in the axial direction of the plunger in the original position and the valve in the normal position. and an adjustment mechanism for adjusting.

In the multi-stage control valve configured in this way,
When the electric circuit applies a first actuation force to the movable iron core, the movable iron core moves until it abuts the plunger, pushing the valve element to the first actuation position. Then, when the electric circuit applies a second actuation force to the movable iron core, the valve element is moved to the second actuation position while pushing the plunger against the elastic force of the second spring.
Therefore, it is now possible to replace multi-stage control valves that were previously limited to manually operated valves with electromagnetically operated valves, and the functions that were previously achieved by combining multiple electromagnetic control valves can now be replaced with a single control valve. This makes it possible for each electromagnetic control valve to perform the same function, thereby achieving the effect of simplifying fluid pressure circuits such as hydraulic circuits and pneumatic circuits. For example, when the valve is moved to the first operating position, multiple ports are communicated with each other through a restricted flow path, and when the valve is moved to the second operating position, multiple ports are communicated with each other through a restricted flow path. They can be communicated through a flow path with a large area.

Moreover, the electromagnetic control valve according to the present invention is provided with an adjustment mechanism that adjusts the certain distance by changing the relative position in the axial direction between the plunger in the original position and the valve element in the normal position. Therefore, by adjusting this adjustment mechanism, it is possible to adjust the first operating position of the valve;
It is possible to cancel manufacturing errors of each component by adjusting the adjustment mechanism during assembly. Therefore, the first operating position of the valve can be accurately set without having to strictly control the manufacturing errors of each component. This means that, for example, when the valve is moved to the first operating position as described above and multiple ports are communicated through a restricted flow path, the restriction can be set accurately. means. It is also possible to change the throttle arbitrarily, so that an electromagnetic control valve that also functions as a variable throttle valve can be obtained.

Hereinafter, embodiments in which the present invention is applied to an electromagnetic directional control valve will be described in detail based on the drawings.

Figure 1 is represented by the symbols shown in Figure 2.
FIG. 3 is a diagram showing the directional control valve 2 at the port 5 position. In Fig. 1, 4 is a valve body, and this valve body 4 includes a through hole for fitting a spool serving as a valve, a pressure port 6 connected to a pressure source such as a pump, and a tank port connected to a tank. 8 and a working port A connected to working equipment such as a hydraulic cylinder.
Four ports, port 10 and B port 12, are formed. A spool 14 is provided so as to be slidable in the axial direction astride these ports. The spool 14 has two lands 16 and 1
8, and all ports are closed in the neutral position, which is the normal position. Further, notches 19 are formed on the outer peripheral surfaces of both ends of each land 16 and 18.

A housing 20 is fixed to the left end surface of the valve body 4. The housing 20 has a through hole formed concentrically with the through hole for fitting the spool 14 of the valve body 4, and has an annular projection 24 on the end face facing the valve body 4. ing. A male thread is formed on the outer peripheral surface of this protrusion 24,
A circular female screw member 26 is screwed together. The female screw member 26 is screwed into the protrusion 24 so as to protrude a certain amount from the end face toward the valve body 4, and is in contact with the valve body 4 via a washer 28. Protrusion 2
A fitting protrusion 30 projects from the end face of the valve body 4, and is fitted into the through hole of the valve body 4, whereby the housing 20 and the valve body 4 are positioned concentrically. Furthermore, the housing 20 and the valve body 4 are kept liquid-tight by an O-ring 32. The housing 20 has a square cross-sectional shape, whereas the female threaded member 26 has a circular cross-sectional shape, and bolt holes are formed in the four corners of the housing 20 that are outside the female threaded member 26. When the inserted bolt 34 is screwed into the valve body 4, the housing 20 is screwed into the female threaded member 26.
It is clamped and fixed to the valve body 4 with the two parts in between. Therefore, by loosening the bolt 34 and rotating the female threaded member 26 by a desired angle, the relative position in the axial direction between the valve body 4 and the housing 20 can be adjusted. The coupling mechanism 35 consisting of the bolt 26 and the bolt 34 also serves as an adjustment mechanism.

A solenoid tube 36 is fixed concentrically to the spool 14 by threading at the end of the housing 20 opposite to the side fixed to the valve body 4. A cylindrical body 40 formed by solidifying the solenoid 38 with synthetic resin is fitted to the outside of the solenoid tube 36.
It is tightened and fixed by a female screw member 42 screwed onto the end of the. Liquid tightness between the solenoid tube 36 and the housing 20 is maintained by an O-ring 44.

Inside the solenoid tube 36 is a movable iron core 46.
and a solenoid pin 48 are provided so as to be slidable in the axial direction. Further, a relay pin 50 is provided in the housing 20 so as to be slidable in the axial direction. The movable iron core 46, the solenoid pin 48, and the relay pin 50 are provided concentrically and in contact with each other, and when the movable iron core 46 is attracted to the right in FIG. 1 by the magnetic force of the solenoid 38,
This operating force is transmitted to the spool 14 to push it to the right. Between the housing 20 and the spring seat 52 fitted to one end of the spool 14 and seated on the stepped surface of the valve body 4,
A spring 54 is provided with a constant preload and normally prevents the spool 14 from moving to the left from its neutral position. Further, an annular plunger 56 is slidably fitted into the relay pin 50, and a spring 58 is applied with a preload greater than the preload of the spring 54 between the plunger 56 and the housing 20. The plunger 56 is pressed against the end surface of the solenoid tube 36. This position is the original position of the plunger 56. The relay pin 50 has a large diameter head 60 at the end protruding from the plunger 56 toward the solenoid pin 48.
0 is the spool 14 with the relay pin 50 in the neutral position
The plunger 56 is kept a certain distance away from the plunger 56 while in contact with the plunger 56 . Movable iron core 46
When the solenoid pin 48 and the relay pin 50 are moved forward as a result of the operation of the solenoid pin 48 and the relay pin 50, the head 60 comes into contact with the plunger 56 and moves it forward against the elastic force of the spring 58. The forward limit of this plunger 56 is the relay pin 5.
A sleeve 62, which is fitted with a sleeve 62, is defined by being sandwiched between the plunger 56 and the housing 20.

The configuration of the left side of the valve body 4 has been described above, but since the configuration of the right side is completely the same, the same reference numerals are given to mutually corresponding components to indicate the correspondence relationship, and detailed explanation will be omitted.

Solenoid 38 has two windings 38a and 38b, as shown in FIG. 3, which are energized when contacts 64 and 66, respectively, are closed.

By using the directional control valve 2 configured as described above, it becomes possible to configure the hydraulic circuit, which was conventionally configured as shown in FIG. 4, as shown in FIG. 5. That is, in FIG. 4, the hydraulic oil pumped up by the pump 72 from the tank 68 via the filter 70 is transferred to the 4-port 3-position directional control valve 7.
4 to the hydraulic motor 76 to rotate it, and as a result, the hydraulic oil discharged from the hydraulic motor 76 is returned to the tank 68 through not only the directional switching valve 74 but also the 3-port 2-position directional switching valve 78. For a certain period of time immediately after the directional control valve 74 is switched from the neutral state (the state where the spool is in the neutral position) to the right or left state,
For a certain period of time immediately before switching from these states to the neutral state, the directional control valve 78 is switched to the right state so that the flow of discharged oil from the hydraulic motor 76 is throttled by the throttle valve 79. It's getting old. As a result, the hydraulic motor 76 slowly starts operating and gradually stops operating.
This is effective in preventing impact from being applied to the device driven by the device and in accurately controlling the stopping position of the device. However, in the case of FIG. 4, in addition to the directional control valve 74, another directional control valve 78 is provided.
In addition to requiring a throttle valve 79 and piping, joint members, and an electric control circuit to connect these, the device becomes expensive, requires a large space, and requires troublesome assembly work. Various disadvantages arise, including an increased incidence of hydraulic oil leakage.

On the other hand, if the 4-port, 5-position directional switching valve 2 of this embodiment is used, the hydraulic motor 76 can be controlled by a single valve, and the above-mentioned disadvantages can be eliminated. That is, if the contact 64 in FIG. 3 is closed, the solenoid 38
Electric power is supplied to one of the windings 38a, and the resulting magnetic force attracts the movable iron core 46 to the right in FIG. As a result, the movable iron core 46 pushes the spool 14 to the right via the solenoid pin 48 and the relay pin 50, so the spool 14 moves against the elastic force of the right spring 54. As a result, notches 19 formed at the ends of lands 16 and 18 allow tank port 8 and A port 10, as well as pressure port 6 and B port 12.
At this time, the head 60 of the relay pin 50 comes into contact with the plunger 56. The magnetic force applied to the movable iron core 46 by the winding 38a is applied to the spool 14 against the elastic force of the spring 54.
Although it is possible to push and move the spring 5
Since the plunger 56 and the spool 14 cannot be pushed to the right against the elastic forces of the pins 4 and 58, when the head 60 comes into contact with the plunger 56, the movable iron core 46 and the solenoid pin 48, relay pin 50 and spool 14
stops moving to the right. The position of the spool 14 at this time will be referred to as a first operating position, and the operating force of the movable iron core 46 will be referred to as a first operating force. In this state, as described above, each port is communicated with each other by the notch 19, so the hydraulic oil pumped from the pump 72 is subjected to the throttling action of the notch 19 of the land 18, and flows from the B port 12 as shown in FIG. It is supplied to the hydraulic motor 76. Further, the hydraulic oil discharged from the hydraulic motor 76 is transferred to the A port 1.
0 to the tank 68 through the tank port 8 while being subjected to the throttling action of the notch 19 of the land 16. That is, in this embodiment, the flow of hydraulic oil supplied to the hydraulic motor 76 also
The flow of hydraulic oil discharged from the land is also restricted, and both so-called meter-in and meter-out are realized. For example, by shortening one of lands 16 and 18, meter-in can be achieved. Alternatively, it is also possible to realize only either one of meter-out.

As described above, when the hydraulic motor 76 starts operating slowly and after a certain period of time, the contact 66 in FIG. 3 is closed, power is also supplied to the remaining winding 38b of the solenoid 38, and the movable iron core The actuation force of 46 increases. Since this second actuation force is large enough to overcome the sum of the elastic forces of the springs 54 and 58, the movable iron core 46 moves further to the right while pushing the plunger 56, and the plunger 56 moves through the sleeve 62. and stops at the position where it abuts against the housing 20. In this state, the spool 14 is moved to the second operating position, and in this second operating position, the A port 10
and tank port 8, as well as pressure port 6 and B port 12, are in communication with each other through passages of sufficient area, and almost all of the hydraulic oil pumped from pump 72 is supplied to hydraulic motor 76. will operate at high speed.

Then, when the device driven by the hydraulic motor 76 moves close to the stop position, the contact 66 in FIG. 3 is opened, and the power supply to the solenoid 38b is cut off. As a result, the movable iron core 4
6 returns to the first operating force, which is smaller than the sum of the elastic forces of springs 54 and 58, and plunger 56 returns to its original position while pushing back movable iron core 46. Along with this, the spool 14 also moves to the first operating position, and the flow of hydraulic oil is again throttled, so that the operating speed of the hydraulic motor 76 is reduced.

After the hydraulic motor 73 is operated for a certain period of time in this state, the contact 64 is opened and the solenoid 38
The power supply to spool 1 is completely cut off.
4 is returned to the neutral position by the elastic force of the spring 54, the supply of hydraulic oil to the hydraulic motor 76 is cut off, and the hydraulic motor 76 is stopped.

The case where the spool 14 is moved to the right has been described above, but the operation is the same when the spool 14 is moved to the left, and the hydraulic motor 76 slowly starts operating in the opposite direction to the above case. , the operating speed is increased after a certain period of time, and then the operating speed is slowed down again and stopped.

As is not clear from the above description, the directional control valve 2 of this embodiment has two pairs of plungers 56 and springs 58 added to the three-position directional control valve, and slight changes are made to the electric circuit including the solenoid 38. It is a directional control valve with only five positions, and a throttling effect can be obtained in two of the five positions.

Moreover, by changing the screwing position of the female screw member 26 with respect to the protrusion 24, the relative position in the axial direction between the housing 20 and the valve body 4 can be changed, resulting in the original position of the plunger 56 and the neutral position of the spool 14. (normal position), in other words, the movable iron core 46 is
8 and the plunger 5 via the relay pin head 60
It is possible to adjust the position of the spool 14 when it abuts the spool 6, ie the first operating position. Therefore, the valve body 4, spool 14, relay pin 5
0. Even if manufacturing errors of the housing 20, sleeve 62, plunger 56, etc. are not strictly controlled, these errors can be canceled out by adjusting the coupling mechanism 35, and the spool 14 can be accurately stopped at the desired first operating position. This allows you to achieve the desired aperture effect.

Furthermore, the fact that the first operating position of the spool 14 can be changed by changing the screwing position of the female screw member 26 with respect to the protrusion 24 means that the throttling effect at this first operating position can be changed arbitrarily. In other words, the throttle valve constituted by the valve body 4 and the spool 14 in this embodiment is a variable throttle valve. Note that if the first operating position of the spool 14 is changed by changing the screwing position of the female screw member 26 with respect to the protrusion 24, the second operating position will also change at the same time, but in the second operating position, each port is Since communication is established with a sufficient flow path area, a change in the second operating position does not substantially affect the flow of hydraulic oil.

Additionally, in this embodiment, when the spool 14 is moved to the first operating position, a throttling effect is obtained, but by increasing the number of ports in the valve body 4, the first operating position of the spool 14 is increased. By changing the communication state of these ports by moving to the working position and the second working position, it is possible to perform more complicated direction switching of the hydraulic fluid,
Further, the spool can be operated at three or more positions on one side of the normal position. Furthermore, it is also possible to arrange two or more springs on only one side of the spool so that the spool can be stopped at a plurality of positions only on one side of the normal position.

Furthermore, the configuration of the electric circuit for applying different operating forces to the movable iron core in two or more stages is not limited to that of this embodiment. Two and three examples are shown in FIGS. 6 to 8. In the case of FIG. 6, a resistor 84 is connected to a solenoid 82 by switching a changeover switch 80
Electric power is supplied through or without the solenoid 82, and the current flowing through the solenoid 82 is changed in stages. In addition, in the one shown in FIG. 7, contacts 90, 92, 9 are connected via a diode 88 to a plurality of taps drawn out from the secondary winding of the transformer 86.
4, etc. are connected, and by selectively closing these contacts, different voltages are applied to the solenoid 96 in stages. In addition, 9
8 is a smoothing capacitor. In addition, the solenoid 100 shown in FIG. 8 is composed of a thick winding 100a and a thin winding 100b, and the contact 10
The amount of current does not change much between when contact 2 is closed and when contact 104 is closed, and the magnetomotive force changes step by step as the number of turns in the energized part changes step by step. be. Note that it goes without saying that the current supplied to each of the solenoids may be alternating current.

FIG. 9 shows yet another embodiment of the present invention. The main difference between this embodiment and the embodiment of FIG. 1 is the location of plunger 56 and spring 58. That is, in the above embodiment, the plunger 56 was disposed at an intermediate position between the movable iron core 46 and the spool 14, whereas in this embodiment, the plunger 56 is disposed at the rear of the movable iron core 46. be. Therefore, each plunger 56 operates such that the right plunger 56 operates when the left movable iron core 46 operates, and the left plunger 56 operates when the right movable iron core 46 operates.
The spool 14 when the movable iron cores 46 on opposite sides are activated, such as when the spool 14 is activated.
This has the effect of defining the first operating position of.

The plunger 56 has a cylindrical housing 20 with a bottom.
It is slidably fitted within the housing 20 and is biased by a spring 58 in the direction of protruding from the housing 20, but the C-shaped retaining ring 106 defines the limit of protrusion. The housing 20 is screwed into a female threaded hole formed at the rear end of the solenoid tube 36 and is fixed by a locking member 108. A hexagonal hole 110 is provided on the rear end surface of the housing 20.
is formed, and the screwing position with respect to the solenoid tube 36 can be adjusted by engaging a hexagonal wrench therewith. A hexagonal hole 112 larger than the hexagonal hole 110 is formed in the locking member 108, and a hexagonal wrench can be engaged with this hexagonal hole 112 to tighten or loosen the locking member. By adjusting the screwing position of the housing 20 with respect to the solenoid tube 36 and fixing it with the locking member 108, the relative position of the housing 20 and the valve body 4 in the axial direction, that is, the spool 14 is adjusted.
The first operating position of the spool 14 can be adjusted by changing the relative positions of the plunger 56 and the plunger 56 in the axial direction. The part of the solenoid tube 36 in which the female threaded hole is formed, the male threaded part of the housing 20 that is screwed into the female threaded hole, and the locking member 10
8 constitutes the coupling mechanism 113. Furthermore, airtightness between the housing 20 and the solenoid tube 36 is maintained by an O-ring 114. Since the other parts are almost the same as those in the previous embodiment, the same reference numerals are given to the parts that perform the same functions to indicate the correspondence therebetween, and a detailed explanation will be omitted.

Although the above embodiments are all examples in which the present invention is applied to wet type electromagnetic directional control valves, it is of course possible to apply the present invention to dry type electromagnetic directional control valves.

Furthermore, the present invention can be applied not only to directional control valves but also to on-off valves. When the valve element is in the normal position, the flow path is blocked, and when the valve element is in the first operating position, the flow path is communicated with a throttling effect. It is also possible for the flow passage to be fully open when in the second operating position. Such an on-off valve has the effect of preventing the so-called water hammer phenomenon from occurring. It is also possible to apply this to a throttle valve so that when the valve element is moved in multiple stages, the degree of throttling can be changed in stages. It goes without saying that the present invention can be implemented in various modifications and improvements without departing from its spirit.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing a multi-stage electromagnetic directional control valve according to an embodiment of the present invention, and FIG. 2 is a diagram showing the directional control valve with symbols. FIG. 3 is a circuit diagram showing the electric circuit of the directional control valve shown in FIG. 1. Fig. 4 is a diagram showing an example of a hydraulic circuit using a conventional electromagnetic directional control valve, and Fig. 5 is a diagram similar to the hydraulic circuit shown in Fig. 4 using the directional control valve shown in Fig. 1. FIG. 2 is a circuit diagram configuring a hydraulic circuit that performs the following functions. FIGS. 6 to 8 are circuit diagrams showing electric circuits in other embodiments of the present invention. FIG. 9 is a front sectional view showing a multi-stage electromagnetic directional control valve which is still another embodiment of the present invention. 2: Directional switching valve, 4: Valve body, 6: Pressure port, 8: Tank port, 10: A port, 12:
B port, 14: Spool (valve), 20: Housing, 24: Projection, 26: Female thread member, 34:
Bolt, 35: Coupling mechanism (adjustment mechanism), 36: Solenoid tube, 38, 82, 96, 100:
Solenoid, 46: Movable iron core, 48: Solenoid pin, 50: Relay pin, 52: Spring seat, 54: Spring (first spring), 56: Plunger,
58: Spring (second spring), 62: Sleeve, 64, 66, 90, 92, 94, 10
2,104: Contact, 80: Changeover switch, 84:
Resistor, 86: Transformer, 88: Diode, 11
3: Coupling mechanism (adjustment mechanism).

Claims (1)

[Claims] 1. A valve body having a plurality of ports; a valve element that is fitted into the valve body and moves in the axial direction to change the communication state between the plurality of ports; a first spring held in the normal position; a movable iron core disposed in series with the valve element and moving in the axial direction to push the valve element in the axial direction against the elastic force of the first spring; A solenoid is provided, and the movable iron core is provided with an operating force having a magnitude different in at least two stages: a first operating force having a magnitude that overcomes the elastic force of the first spring, and a second operating force larger than the first operating force. an electric circuit that provides an electrical circuit that is stationary at the original position while the movable iron core moves a certain distance in a direction to push the valve element, and remains stationary at the original position while the movable iron core moves beyond the certain distance; a plunger that moves together with the movable iron core, and a force greater than the first operating force minus the elastic force of the first spring,
a second spring held in the original position by an elastic force smaller than the second operating force minus the elastic force of the first spring; a plunger in the original position; and a valve in the normal position. and an adjustment mechanism that adjusts the certain distance by changing the relative position in the axial direction. 2. The plunger is a cylindrical member provided at an intermediate position between the movable iron core and the valve element, and the movable iron core engages the valve element through a pin provided through the plunger. The valve body is configured to be pushed and moved, and the adjustment mechanism is configured by a coupling mechanism that couples a housing that holds the plunger and the second spring to the valve body in a variable relative position in the axial direction. Claim 1
The multi-stage solenoid control valve described in . 3. The coupling mechanism is screwed into a male thread formed on the outer peripheral surface of an annular protrusion that protrudes concentrically with the plunger on either the housing or the valve body, and is connected to the housing at one end surface. an annular female threaded member that abuts the other valve body; and a plurality of tightening bolts that tighten the housing and the valve body in a direction toward each other and fix the two with the female threaded member interposed therebetween. 3. A multi-stage solenoid control valve according to claim 2. 4. The plunger is disposed on the opposite side of the movable iron core with the valve element in between, and is in contact with the movable iron core at least through the valve element, and the adjustment mechanism is , a housing that holds the plunger and the second spring, and a coupling mechanism that couples the valve body in a variable relative position in the axial direction.
The multi-stage solenoid control valve described in . 5. The valve element is a spool with a land, and a notch whose cross-sectional area changes along the axial direction of the spool is formed on the outer peripheral surface of the end of the land, and the certain distance is , the size is selected such that when the spool moves from the normal position by the certain distance, the plurality of ports communicate with each other via a throttle passage formed by the notch and the valve body. A multi-stage electromagnetic control valve according to any one of claims 1 to 4.