JPH038851Y2 - - Google Patents

Description

[Detailed description of the invention] [Summary] In one valve device, the pressure at the output port is controlled by the value of the current applied to the proportional solenoid;
It is possible to switch the direction of two ports, and one valve device has two valve functions.

[Industrial application field]

When driving pneumatic equipment such as air cylinders, a switching valve and a pressure control valve are often used together, and the present invention relates to a proportional control valve that has both the functions of a switching valve and a pressure control valve.

[Conventional technology]

FIGS. 4 and 5 are circuit diagrams showing how a conventional proportional control valve is used. When driving an air cylinder, etc., the proportional control valve V ₁ , which controls the pressure of the compressed air supplied to the air cylinder, and the switching valve V ₂ , which switches the on/off or direction of the compressed air supply to the air cylinder, are usually used together. be done. In the proportional control valve _V1 , the port P is connected to a pressure source such as a compressor, and compressed air before pressure control, that is, primary pressure is input. The secondary pressure whose pressure is controlled by the proportional control valve _V1 is output from the A port. R is an exhaust port.

The secondary pressure output from the proportional control valve _V1 is supplied from the A port to the ports _CYL1 to _CYL2 of the air cylinders via the switching valve _V2 . In the illustrated example,
The output pressure from proportional control valve V ₁ is from port P of switching valve V ₂ → port A → port CYL ₁ of air cylinder.
Air is supplied to the air cylinder in the following order, and the air is exhausted from port CYL ₂ → port B of switching valve V ₂ → port R2,
is exhausted through the route. As a result, the piston in the air cylinder moves toward the rod cover. When switching valve V ₂ is switched, port A communicates with port R1 and port B communicates with port P, so on the air cylinder side, port CYL ₂ becomes air supply, port CYL ₁ becomes exhaust air, and the piston rod moves to the head cover side. do.

In Figure 4, both ports of the air cylinder CYL ₁ ,
For both CYL ₂ , compressed air is supplied with pressure controlled by the proportional control valve V ₁ , but in order for the switching valve V ₂ to operate smoothly, a pressure higher than the minimum driving pressure is required, and the proportional control valve V ₁ If the obtained compressed air is below this minimum driving pressure, the switching valve _V2 will not be able to operate smoothly. On the other hand, in the example shown in Fig. 5, compressed air whose pressure is controlled by proportional control valve V ₁ is supplied only to port CYL ₁ of the air cylinder, and to port CYL ₂ , compressed air is supplied from the front stage of proportional control valve V ₁ . Position switching valve V ₂
is connected. Therefore, the extrusion direction of the air cylinder is controlled by thrust, the return side is supplied with primary pressure, and the air cylinder is driven at high speed by lowering the pressure on the port CYL ₁ side. Moreover, regardless of the compressed air pressure obtained by the proportional control valve V ₁ , the switching valve V ₂
becomes operational.

[Problem that the invention attempts to solve]

When driving pneumatic equipment in this way, in addition to the operation using the switching valve _V2 , there is an increasing need for pressure control using a proportional control valve or the like. In recent years, as a method for controlling pressure or flow rate, proportional control valves and servo valves that use proportional solenoids, nozzle flappers, force motors, etc. as actuators and are controlled by electrical signals have come into use.

Among these, the so-called pressure proportional control valve is functionally a three-way valve, and in addition to the above-mentioned valves, it is generally used for reciprocating objects such as cylinders.
As shown in Fig. 4, the direction can be changed by a four-way valve, or the compressed air pressure obtained by the proportional control valve _V1 can be
If it is below the minimum driving pressure of the switching valve _V2 , it is necessary to combine it with a three-way valve as shown in FIG. 5, or to combine two of the above valves. Therefore, when using the above valve, at least two valves must be driven, and especially when pressure control is required only on one cylinder chamber side as shown in Fig. 5, the proportional control valve V ₁ must be driven. Although the switching valve _V2 can be driven independently of the obtained compressed air pressure, it is expensive in terms of circuitry and cost.

The technical problem of the present invention is to solve these problems with conventional proportional control valves, to realize the functions of a proportional control valve and a switching valve in one valve device, and to reduce the amount of compressed air obtained by the proportional control valve. The purpose is to enable driving without being affected. For example, when controlling a welding gun cylinder, using a proportional control valve,
When performing pressure control, especially when direction switching is required and pressure control is required only on one side,
It is possible to control the pressure on one side and change the direction by only sending an electric signal to one valve, thereby providing a simple and inexpensive valve in terms of circuitry and cost.

[Means for solving problems]

1 and 2 are sectional views showing an embodiment of the proportional control valve according to the present invention, with FIG. 1 showing the stopped state and FIG. 2 showing the controlled operating state, respectively. Two cylinder chambers 20 and 21 are formed in the main body 4, the first cylinder chamber 20 houses the first spool 9, and the second cylinder chamber 21 houses the second spool 12. ing. Both spools 9, 12 have three large diameter sliding parts 22, 23, 24.
, and each large-diameter sliding portion 22, 23, 24
A small-diameter communication portion is formed between the two, creating a space.

At one end of the first cylinder chamber 20, one end of the first spool 9 is connected to the proportional solenoid 1, and the other end forms a first pressure chamber 10a facing the other end of the first spool 9. Also, the large-diameter sliding portion 2 is in communication with the inside of the first cylinder chamber 20 and is located in the middle.
A port 6 that is opened and closed at 3, and P port 5a that is arranged on both sides of the A port 6 and that is supplied with primary pressure.
, an R1 discharge port 7, and a feedback port 8a that communicates with the A port 6 and the pressure counterchamber 10a of the first cylinder chamber 20, respectively.

The partition wall 19 between the two cylinder chambers 20 and 21 is
A supply port 5b opened at a position corresponding to the P port 5a penetrates through the supply port 5b. The second cylinder chamber 21 is formed with a pressure counter chamber 10b that communicates with the pressure counter chamber 10a of the first cylinder chamber 20 via the feedback port 8b, and the pressure counter chamber 10b of the second spool 12 is connected to the pressure counter chamber 10b. R2 discharge port 13
and a B port 14 which communicates with the supply port 5b via the other small diameter communication part and is opened and closed by the large diameter sliding part 23 in the middle.

In a chamber 25 of the second cylinder chamber 21 on the opposite side of the pressure counter chamber 10b, a switching pressure setting spring 15 is interposed between an externally adjustable spring receiver 16 and the second spool 12.

[Effect]

When no excitation current is applied to the proportional solenoid 1, no driving force is applied to the first spool 9, so the first spool 9 is moved toward the proportional solenoid 1 by the auxiliary spring 11, as shown in FIG. Furthermore, even if primary pressure is supplied to the supply ports 5a and 5b by a compressor, etc., the second cylinder chamber 2
Since fluid pressure does not act on the pressure counterchamber 10b of No. 1,
The second spool 12 is a switching pressure setting spring 15,
Move to the pressure counter chamber 10b side. The compressed air supplied from the supply port 5a is then transferred to the supply port 5b.
B port 1 of the second cylinder chamber 21 via
Output from 4.

When the proportional solenoid 1 is energized now, the first spool 9 moves toward the opposite pressure chamber 10a, but while the value of the current flowing to the proportional solenoid 1 is small, B
Compressed air is output from port 14. When the applied current increases, as shown in FIG. 2, the A port 6 communicates with the supply port 5a, and compressed air is output from the A port. In this case, secondary pressure also acts on the pressure counter chamber 10a from the A port 6 through the feedback port 8a, and at a position where this secondary pressure, the force from the auxiliary spring 11, and the driving force from the proportional solenoid 1 are balanced, The first spool 9 is stabilized. Therefore, as shown in FIG. 3, the secondary pressure P _A output from the A port 6 has a strength proportional to the current applied to the proportional solenoid 1. Further, the secondary pressure is supplied to the second cylinder chamber 21 through the feedback port 8b.
It also flows into the pressure counter chamber 10b, and the second spool 12
to the switching pressure setting spring 15 side. The second spool 12 is stabilized at a position where the secondary pressure acting on the second spool 12 and the spring pressure of the switching pressure setting spring 15 are balanced. That is, when the secondary pressure acting on the second spool 12 increases, the second spool 12 moves toward the switching pressure setting spring 15, and
As shown in FIG. 2, the B port 14 communicates with the exhaust port 13.

Therefore, the A port 6 and the B port 14 are connected to the air cylinder port CYL ₁ , as shown in FIG.
When connected to CYL ₂ , if the current to proportional solenoid 1 is off or at a small current value,
Compressed air is supplied from the B port, and the A port 6 is in an exhaust state. When the current applied to the proportional solenoid 1 becomes larger than a predetermined value, that is, the switching current value _I1 shown in FIG. It communicates with the air and enters the exhaust state. That is, the state is as shown in the circuit diagram of FIG. In addition, the secondary pressure output from the A port 6 is a value that is pressure-controlled according to the value of the current flowing to the proportional solenoid 1.
The direction of the B port 14 is changed and the flow rate is controlled depending on the value of the current flowing therein. Also,
According to the present invention, by adjusting the switching pressure setting spring, the B port pressure can be arbitrarily controlled as shown by the chain line in FIG. 3, and the influence of the minimum driving pressure can be reduced by reducing the minimum driving pressure. It can operate reliably without any damage. Therefore, there is no need to use the switching valve _V2 as shown in FIG. 5, and the cost becomes low.

〔Example〕

Next, examples will be used to explain how the proportional control valve according to the present invention is actually implemented. FIG. 1 is a sectional view showing an embodiment of the proportional control valve, and FIG. 2 is a sectional view showing the operating state of the proportional control valve. In FIG. 1, the structure will first be explained.

1 is a proportional solenoid, which is mounted on the cover 2 of the proportional control valve. Two spools 9 and 12 are housed in the main body 4 of the proportional control valve parallel to each other with a partition wall 19 in between, and the first spool 9 is connected to the proportional solenoid 1. The main body 4 has a first
Two cylinder chambers 20 and 21 containing a spool 9 and a second spool 12 are formed, and a cover 2 is fixed to the main body 4. Both spools 9,
12, large diameter sliding parts 22, 23, 2 that slide on the inner walls of the cylinder chambers 20, 21 to switch ports.
4 is formed, and each large diameter sliding portion 22, 2
The space between 3 and 24 is formed to have a small diameter so that fluid can pass therethrough.

The main body 4 includes a cylinder chamber 2 for the first spool.
0, a P port 5a, an A port 6, and an R1 discharge port 7 are formed. Also, A port 6
communicates with the pressure counterchamber 10a of the cylinder chamber 20 via the feedback port 8a, and further communicates with the pressure counterchamber 10b of the second cylinder chamber 21 via the feedback port 8b. Bulkhead 19
A P port 5b that communicates the two cylinder chambers 20 and 21 is opened at a position corresponding to the P port 5a.

In addition, in the second cylinder chamber 21, a B port 14 is located at a position approximately corresponding to the A port 6, and an R2 exhaust port 13 is located at a position corresponding to the R1 exhaust port 7.
is opened.

A spring receiver 16 is built into the inside of the cover 2.
It is supported by the cover 2 via a switching pressure setting screw 18 and fixed with a lock nut 17. . A switching pressure setting spring 15 is interposed between the spring receiver 16 and the second spool 12. A chamber 25 housing the setting spring 15 communicates with the outside via a communication hole 26, a spool shaft chamber 27, and a relief port 3.

[Operation explanation]

If the primary pressure is being supplied to the supply ports 5a and 5b from a pressure source such as a compressor, and no current is being applied to the proportional solenoid 1, or if the current is small, the current will be applied from the port 5b to the B port 14.
Non-pressure controlled fluid flows to.

When the current value applied to the proportional solenoid 1 is gradually increased, a force proportional to the current is applied to the first spool 9, fluid from the P port 5a flows to the A port 6, and the pressure in the A port 6 is reduced to zero. Pressure counter chambers 10a, 10 through the air back ports 8a, 8b
It is transmitted to b.

Here, the first spool 9 side is the proportional solenoid 1
If the pressure counter chamber 10a side is lower due to the balance between the force and the force due to the secondary pressure of the pressure counter chamber 10a,
The flow rate between the P port 5a and the A port 6 increases, resulting in the state shown in FIG. Conversely, if the pressure on the opposite chamber 10a side is high, the A port 6 and R1 discharge port 7 will communicate,
Drain the fluid from A port. In this way, the A port 6 outputs a pressure proportional to the applied current.

On the other hand, on the second spool 12 side, the fluid pressure reduced on the first spool 9 side is transferred to the feedback port 8.
It joins the pressure counter chamber 10b via b and moves to a position where it balances with the switching pressure setting spring 15. Due to an increase in the pressure at the A port 6, that is, an increase in the current applied to the proportional solenoid 1, the second spool 12
moves in the direction of compressing the setting spring 15, and B
The port 14 and the P port 5b are closed, and the B port 14 communicates with the R2 discharge port 13. At this time, the B port valve opening degree for the 5b supply side and the R2 discharge side is proportional to the applied current.

FIG. 3 shows the relationship between the output pressures of the A and B ports with respect to the applied current. The solid line is the A port pressure, and the chain line is the B port pressure. As shown by the chain line, the B port switching pressure can be set arbitrarily by adjusting the switching pressure setting spring, and as a result, reliable operation is possible without being affected by the minimum drive pressure as in the conventional case.

By arbitrarily selecting the applied current value in this way, in addition to the desired A-side pressure and switching state,
Side port supply and exhaust throttling conditions will be obtained. It goes without saying that the proportional control valve of the present invention can be applied to control not only gas but also liquid.

[Effect of idea]

As described above, according to the present invention, direction switching and pressure control of the secondary pressure are possible in one valve device, and the secondary pressure can be arbitrarily set by adjusting the switching pressure setting spring, and the minimum drive By controlling the valve so that it is not affected by pressure, a switching valve and a pressure control valve, which are normally used together, can be realized in one valve device. Katsu1
Two valve functions can be controlled with only one input control signal. Furthermore, the switching set pressure can be changed arbitrarily, and both side pressure application used for intermediate stopping of the cylinder, etc., can be made by adjusting the applied current.
The balance pressure at that time can also be arbitrarily selected and set. By appropriately selecting the applied current,
The air supply and exhaust control orifices of the B port can be varied, making it possible to control the speed of cylinders, etc.

[Brief explanation of drawings]

Figure 1 is a sectional view showing an embodiment of the proportional control valve according to the present invention, Figure 2 is a sectional view showing the control operation state of the proportional control valve, and Figure 3 is the applied current and secondary pressure in the proportional control valve. 4 and 5 are piping diagrams using a conventional proportional control valve. In the figure, 1 is a proportional solenoid, 4 is a main body,
5a, 5b are P ports, 6 is A port, 7 is R1
Exhaust ports, 8a and 8b are feedback ports, 9 is a first spool, 10a and 10b are pressure counter chambers, 11 is an auxiliary spring, 12 is a second spool, 13
14 is the R2 exhaust port, 14 is the B port, 15 is the switching pressure setting spring, 20 is the first cylinder chamber, and 21 is the second cylinder chamber.

Claims (1)

[Claims for Utility Model Registration] In one valve device, two cylinder chambers are formed in the main body, and a first cylinder chamber is formed in one of the cylinder chambers.
a second spool built into the other cylinder chamber, each spool having three large diameter sliding parts and a small diameter communication part therebetween; , one end of the first spool is connected to a proportional solenoid, and the other end of the first cylinder chamber is a first pressure counter chamber facing the other end of the first spool, and the first pressure counter chamber is connected to the first pressure counter chamber. , a built-in spring that biases the first spool in a direction opposite to the driving force of the proportional solenoid; an A port that communicates with the inside of the first cylinder chamber and is opened and closed by a large-diameter sliding portion in the middle; A P port arranged on both sides of the A port and connected to a pressure source;
The R1 discharge port communicates with the A port, and the first
Feedback ports communicating with the pressure counterchambers of the cylinder chambers are formed respectively, and the partition wall between both cylinder chambers is penetrated by a supply port opened at a position corresponding to the P port. The second cylinder chamber is formed with a pressure counter chamber that communicates with the pressure counter chamber of the first cylinder chamber via a feedback port, and is always connected to a small diameter communicating portion on the pressure counter chamber side of the second spool. It has an R2 discharge port that communicates with it, and a B port that communicates with the P port through the other small diameter communication part and is opened and closed by the large diameter sliding part in the middle. What is the pressure counterchamber of the second cylinder chamber? A proportional control valve characterized in that, in the opposite chamber, a switching pressure setting spring is interposed between an externally adjustable spring receiver and the second spool.