JPH0735106A - Air cylinder drive control circuit and flow rate control valve - Google Patents

Abstract

PURPOSE:To provide an air cylinder drive control circuit and a flow rate control valve which can make differential pressure capable of rapidly starting transportation of a piston. CONSTITUTION:A directional changeover valve 5 is switched to a position (b) for shrinking a piston rod 3, and an air supply source P and a second intake/ exhaust passage 4b are communicated mutually. In this case, since discharge of air inside a cylinder chamber 1a on the head side, is suppressed by a throttle valve 12 provided in a first intake/exhaust passage 4a, a relief valve 11 is opened by pressure inside a second main pipe line. As a result, a differential pressure between a pressure Pa enough for starting the operation of piston 2 and the pressure pb is quickly generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cylinder drive control circuit and a flow control valve.

[0002]

2. Description of the Related Art Conventionally, various air cylinder drive control circuits have been proposed which supply high pressure air to an air cylinder to control the moving speed of a piston. FIG. 4 shows a drive control circuit in which the piston 52 of the air cylinder 51 is reciprocated at a low speed. This circuit includes two chambers defined by a piston 52 in an air cylinder 51, that is, a head side cylinder chamber 51a, a rod side cylinder chamber 51b, and a direction switching valve 5.
3 are connected by supply / discharge passages 54a and 54b, respectively. The other end of the direction switching valve 53 is connected to the air supply source P and the silencer S.

The supply / discharge passages 54a, 54b are provided with throttle valves 55a, 55b, respectively, and check valves 56a, 56b are connected in parallel to the respective throttle valves 55a, 55b. The check valves 56a and 56b are connected by the direction switching valve 53 so as to be in the forward direction when the supply / discharge passages 54a and 54b are on the air supply side.

Then, as shown in FIG. 4, when the direction switching valve 53 is switched to move the piston 52 back (contract the piston rod 52a), high-pressure air from the air supply source P is transferred to the direction switching valve 53 and Check valve 5 in supply / discharge passage 54b
It is supplied to the rod side cylinder chamber 51b via 6b.
On the other hand, the air in the head side cylinder chamber 51a is supplied to the supply / discharge passage 5
4a is discharged through the throttle valve 55a and the direction switching valve 53.

Air is discharged based on the throttle amount of the throttle valve 55a in the supply / discharge passage 54a. This throttle amount determines the moving speed (reciprocating speed) of the piston 52. That is,
The larger the throttle amount is, the lower the moving speed (reciprocating speed) of the piston 52 becomes. FIG. 5 shows the internal pressure Pa of the head side cylinder chamber 51a and the rod side cylinder chamber 51b at this time.
7 shows the displacement of the piston 52 with respect to the internal pressure Pb.

[0006]

However, as shown in FIG. 5, the time required for the piston 52 to start moving after the direction switching valve 53 is switched (in this case,
4.4 seconds) was very long. This is because the throttle valve 55 in the supply / discharge passage 54a is used to return the piston 52 at a low speed.
a is provided, and the throttle valve 55a limits the discharge of air from the head-side cylinder chamber 51a, so that the internal pressure Pa thereof does not decrease rapidly. That is, it takes time for the differential pressure between the internal pressure Pb and the internal pressure Pa sufficient to start the backward movement of the piston 52.

Therefore, an air pressure circuit, in which the throttle valve 55a and the check valve 56a are connected in parallel, is used, for example, as an actual open circuit 53-62588.
It is conceivable to replace it with the pressure regulating valve shown in. As shown in FIG. 6, the pressure adjusting valve 58 has a structure in which a valve 58a and a series circuit of a throttle valve 58b and a check valve 58c are connected in parallel to the valve 58a. The valve 58a corresponding to the throttle valve 55a is a valve that opens and closes on the basis of the pressure on the upstream side, which is the upstream side.

However, although the adjusting pressure of the valve 58a can be adjusted by one elastic body, when the adjusting pressure for one upstream side is determined, the adjusting pressure for the other upstream side is inevitably determined. Will be done. As a result, it is difficult to change and use the adjustment pressure in various ways, and determining the adjustment pressure for promptly starting the movement of the piston sacrifices the other adjustment pressure. Is not the original use of. Further, if the valve 58a fails for some reason and becomes inoperable, air cannot be supplied to the head side cylinder chamber 51a, and the air cylinder becomes inoperable.

The present invention has been made to solve the above problems, and provides an air cylinder drive control circuit and a flow control valve capable of producing a differential pressure capable of promptly starting the movement of a piston. The purpose is to

[0010]

The invention according to claim 1 is
In an air cylinder drive control circuit in which two chambers defined by pistons in an air cylinder and a direction switching valve are connected by a supply / discharge passage, and a throttle valve is provided in each supply / discharge passage, a direction is provided in each supply / discharge passage. A check valve is connected in parallel to the throttle valve so that it is in the forward direction when it is on the air supply side by switching the switching valve and in the reverse direction when it is on the air discharge side, and at least one of the supply and discharge passages is connected. The gist is that a relief valve whose upstream side pressure is set as the relief pressure is connected in parallel to the throttle valve.

According to the second aspect of the present invention, the valve main body has one supply / discharge port, and the first main pipe line and the second main pipe line are formed with the partition wall sandwiched therebetween, and both pipe lines communicate with the partition wall. A check valve that forms a first passage and a second passage and opens and closes the first passage is provided on the first main conduit side, and a needle valve that is inserted into the opening of the second passage is provided. In the provided flow control valve, a third passage communicating with both the pipelines is formed in the partition wall, a valve seat is provided in the third passage, and the third main passage is elastically supported by the elastic member. The gist of the present invention is to provide a diaphragm for opening and closing the valve seat against the elastic force according to the pressure in the first main conduit.

[0012]

Therefore, according to the first aspect of the present invention, when the air cylinder is contracted, the throttle valve opens the relief valve by using the pressure accumulated in the supply / discharge passage connected to the head side cylinder chamber as the relief pressure. . As a result, it is possible to shorten the time from the switching of the direction switching valve to the air cylinder contraction position to the start of contraction of the air cylinder.

According to the second aspect of the invention, when the air cylinder is contracted, the pressure accumulated in the second main pipe passage communicating with the head side cylinder chamber is applied to the diaphragm elastically supported by the elastic member by the throttle valve. When the pressure becomes larger than the elastic force of the elastic member, the diaphragm is pushed up to open the valve seat. As a result, it is possible to shorten the time from the switching of the direction switching valve to the air cylinder contraction position to the start of contraction of the air cylinder.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. FIG. 1 shows a drive control circuit in which a piston 2 of an air cylinder 1 is reciprocated at a low speed. Inside the air cylinder 1, a piston 2 is housed in close contact with the inner peripheral wall of the air cylinder 1 so as to be slidably movable in the longitudinal direction (left and right direction in FIG. 1). Is projected on the right side of. A head side cylinder chamber 1a and a rod side cylinder chamber 1b are defined by the piston 2 on both left and right sides of the piston 2. A first supply / discharge passage 4a is connected to the head side cylinder chamber 1a, and a second supply / discharge passage 4b is connected to the rod side cylinder chamber 1b. The supply and discharge passages 4a and 4b are connected to the direction switching valve 5. The other end of the direction switching valve 5 is connected to the air supply source P and the silencer S.

The directional switching valve 5 is a 2-position 5-port type electromagnetic switching valve, and when the electromagnetic solenoid 6 is demagnetized, it is switched and held at the home position b by the biasing force of the spring 7. Has become. Further, in the excited state of the electromagnetic solenoid 6, it can be switched to the a position.

At the position a, the direction switching valve 5 communicates the first supply / discharge passage 4a with the air supply source P and the second supply / discharge passage 4b with the silencer S. At the position b, the first supply / discharge passage 4a and the muffler S are communicated with each other, and the second supply / discharge passage 4b is communicated with the air supply source P.

A throttle valve 8 is provided in the second supply / discharge passage 4b, and a check valve 9 is connected in parallel to the throttle valve 8. The check valve 9 is connected by the direction switching valve 5 so as to be in the forward direction when the second supply / discharge passage 4b is on the air supply side.

A flow control valve 1 is provided in the first supply / discharge passage 4a.
0 is provided. The flow control valve 10 is a relief valve 11
The throttle valve 12 and the check valve 13 are connected in parallel. The check valve 13 is connected by the direction switching valve 5 so as to be in the forward direction when the first supply / discharge passage 4a is on the air supply side.

Next, the specific structure of the flow control valve 10 will be described with reference to FIG. The flow control valve body 10a is provided with a first port 14 which should be connected to the direction switching valve 5 side, and by communicating with the first port 14 and closing the lower surface of the flow control valve body 10a with a lid body 15, A first main pipe line 16 is formed. A second port 17 to be connected to the air cylinder 1 side is provided on the side of the flow control valve body 10a that opposes the first port 14, and the second main conduit 18 communicating with the second port 17 is the first main pipe. It is formed in parallel with the passage 16 via a partition wall 19.

The partition wall 19 for partitioning the first main pipe line 16 and the second main pipe line 18 has a first port 1 from the second port 17 side.
The first passage 20 and the second passage 2 in order toward the 4 side.
First and third passages 22 are provided. A valve seat 23 is fitted into the partition wall 19 of the third passage 22 so as to project toward the second main pipe line 18 side.

A throttle valve 12 is provided above the flow control valve body 10a at a position corresponding to the first passage 20. The seat body 24 of the throttle valve 12 is fitted to the flow control valve body 10a, and the seat body 24 is screwed with a valve shaft 25 having a male thread on its side surface. The adjusting groove 2 is provided at the base end 26 of the valve shaft 25.
7 is provided, the valve shaft 25 is kept airtight by the O-ring 28, and is extended to the first passage 20. The tip 29 of the valve shaft 25 is formed in a tapered shape,
A part of it is interposed in the first passage 20.

Therefore, when the tip end of the driver is engaged with the adjusting groove 27 and rotated, the height position of the tip end portion 29 of the valve shaft 25 changes. That is, the opening area of the first passage 20 changes based on the amount of rotation of the driver, and the flow rate of the air flowing through the first passage 20 can be adjusted.

A check valve 13 is provided at a position corresponding to the second passage 21 above the flow control valve body 10a. The seat body 30 of the check valve 13 is fitted to the flow control valve body 10a, and the guide portion 31 recessed in the center of the seat body 30 has a valve shaft 33 having an opening / closing valve 32 at one end.
Is slidably inserted along. And the on-off valve 3
A spring 34 is interposed between 2 and the seat body 30, and the opening / closing valve 32 always closes the open end of the second passage 21 by the urging force of the spring 34.

Therefore, in the second passage 21, when air flows into the first main conduit 16 and air pressure against the elastic force of the spring 34 is applied to the on-off valve 32, the on-off valve 32 is pushed up. The first main pipe line 16 and the second main pipe line 18 are communicated with each other, and air is allowed to flow from the first main pipe line 16 to the second main pipe line 18. Further, when the second passage 21 is closed by the opening / closing valve 32, air is prevented from flowing from the second main pipe line 18 to the first main pipe line 16.

A relief valve 11 is provided at a position corresponding to the third passage 22 above the flow control valve body 10a. The seat 35 of the relief valve 11 is the flow control valve body 10
It is formed so as to be fitted to a and project to the outside of the flow control valve body 10a. A cavity 36 is provided inside the seat 35, and a lower surface of the seat 35 is closed by a diaphragm 37 having elasticity. A diaphragm 37 is provided inside the cavity 36.
The pressing valve 38 is disposed in contact with the pressing valve 38, and the pressing valve 38 is provided with a spring receiver 40 via a spring 39.

On the other hand, from the upper part of the seat 35, an adjusting shaft 41 having a male thread is screwed into the side surface and abuts on the spring receiver 40. An adjusting groove 42 is provided on the head of the adjusting shaft 41, and a pressing force of the pressing valve 38 against the diaphragm 37 is adjusted by engaging a screwdriver or the like with the adjusting groove 42 and rotating the same. There is. The pressure valve 38 is in contact with the valve seat 23 fitted to the partition wall 19 via the diaphragm 37.

Therefore, the air in the second main pipeline 18 is pushed up by the diaphragm 37 when the air pressure against the pushing force of the push valve 38 is applied to the diaphragm 37, and the push valve 38 is pushed up by the first main pipeline. 16 and the 2nd main pipeline 18 are open for free passage. Then, when the air flows through the third passage 22 into the first main pipe 16, the air pressure in the second main pipe 18 decreases, and the pressing force of the pressing valve 38 causes the third passage 22 to be closed again. Has become.

Next, the operation of the air cylinder drive control circuit and the flow rate control valve configured as described above will be described. First, in the initial state, the electromagnetic solenoid 6 of the direction switching valve 5 is demagnetized, and the direction switching valve 5 is held at the home position b position by the pressing biasing force of the spring 7. At this time, the piston rod 3 is in a contracted state, and the pressure Pb in the rod side cylinder chamber 1b is higher than the pressure Pa in the head side cylinder chamber 1a.

In order to extend the piston rod 3, first, the electromagnetic solenoid 6 is excited. Then, the direction switching valve 5 is switched to the a position, the air supply source P and the first supply / discharge passage 4a are communicated with each other, and the silencer S and the second supply / discharge passage 4b are connected.
Are communicated. The air supplied from the air supply source P is the first
It is supplied into the head side cylinder chamber 1a through a check valve 13 connected in parallel to the supply / discharge passage 4a. When air is supplied into the head side cylinder chamber 1a, the pressure Pa becomes higher than the pressure Pb, and the piston 2 moves in the extension direction of the piston rod 3 due to the pressure difference between the two pressures.

On the other hand, the air in the rod side cylinder chamber 1b is discharged to the silencer S through the second supply / discharge passage 4b.
Since the throttle valve 8 is provided in the supply / discharge passage 4b, the air is slowly discharged to the silencer S based on the throttle amount of the throttle valve 8. That is, since the discharge of air is restricted by the throttle valve 8, the extension of the piston rod 3 is performed at a low speed.

Next, in order to contract the piston rod 3, the electromagnetic solenoid 6 is demagnetized. Then, the direction switching valve 5 is switched to the b position, the air supply source P and the second supply / discharge passage 4b are communicated with each other, and the first supply / discharge passage 4a and the silencer S are connected.
Are communicated. The air supplied from the air supply source P is the second
It is supplied into the rod side cylinder chamber 1b through a check valve 9 connected in parallel to the supply / discharge passage 4b. At this time, the air in the head side cylinder chamber 1a is discharged to the muffler S through the first supply / discharge passage 4a, but the discharge of the air is restricted by the throttle valve 12 provided in the first supply / discharge passage 4a. Therefore, the pressure Pc in the second main pipeline 18 shown in FIG. 2 becomes high.

However, when the pressure Pc becomes larger than the pressing force of the spring 39 provided on the relief valve 11, the valve seat 23
The diaphragm 37 that is in contact with is pushed up and the first main pipe line 16 and the second main pipe line 18 communicate with each other through the third passage 22. Then, the air staying in the second main conduit 18 is discharged to the first main conduit 16 through the third passage, so that the pressure Pc rapidly decreases. That is, the pressure Pa in the head-side cylinder chamber 1a rapidly decreases, and a pressure difference between the pressure Pa and the pressure Pb sufficient to start the operation of the piston 2 also rapidly occurs.

When the pressure Pc becomes smaller than the pressing force of the spring 39, the diaphragm 37 again contacts the valve seat 23 and closes the third passage 22. In the state where the third passage 22 is closed, the air is discharged while being regulated by the throttle valve 12, so that the piston 2 slowly moves in the contracting direction of the piston rod 3.

FIG. 3 shows the pressures Pa and Pb and the displacement of the piston 2 with respect to the time t when the piston rod 3 contracts. When the directional control valve 5 is switched to the b position at time T1, the above-described action causes a pressure difference between the pressure Pa and the pressure Pb sufficient to start the movement of the piston 2 to be rapidly generated. The time required for the piston 2 to start moving after the direction switching valve 5 is switched is 0.7 seconds in this case.

Therefore, in this embodiment, the relief valve 1 is provided in the flow control valve 10 in parallel with the throttle valve 12 and the check valve 13.
1 is provided. Therefore, although the piston 2 moves at a low speed, it is possible to eliminate the delay in the decrease in the pressure Pa at the start of contraction of the piston rod 3.

When working with the air cylinder 1,
There is a possibility that the target contraction start timing may deviate due to fluctuations in the load applied to the piston rod 3. In this embodiment, since the pressing force of the pressing valve 38 can be adjusted by the adjusting shaft 41 provided in the relief valve 11, even if it deviates from the target contraction start timing, it can be easily corrected.

Further, in a state where the relief valve 11 does not operate,
For example, there is a possibility of failure if used for many years. Even in this case, the relief valve 11 includes the throttle valve 12 and the check valve 13
Since they are provided in parallel with each other, only the throttle valve 12 and the check valve 13 can function as a flow rate control valve.

The present invention is not limited to the above-described embodiments, but can be embodied with the following modifications without departing from the spirit of the invention. (1) The arrangement of the relief valve 11, the throttle valve 12, and the check valve 13 is not limited to the above embodiment as long as they are arranged in parallel. For example, the positions of the relief valve 11 and the throttle valve 12 may be reversed, or the positions of the throttle valve 12 and the check valve 13 may be reversed. Of course, other arrangement order may be used.

(2) The valve seat 23 and the seat body 24 of the throttle valve 12 may be formed integrally with the flow control valve body 10a. (3) In this embodiment, two mufflers S are provided and the direction switching valve 5 is a 2-position 5-port type. However, one muffler S is used and the direction switching valve 5 is a 2-position 4-port type. Good.

[0040]

As described above in detail, according to the present invention, there is an excellent effect that it is possible to create a differential pressure capable of promptly starting the movement of the piston.

[Brief description of drawings]

FIG. 1 is a block diagram showing a drive control circuit of an air cylinder.

FIG. 2 is a sectional view showing a flow control valve.

FIG. 3 is an explanatory diagram showing respective pressures and piston displacement amounts with respect to time when the piston rod contracts.

FIG. 4 is a block diagram showing a drive control circuit of a conventional air cylinder.

FIG. 5 is an explanatory diagram showing each pressure and the amount of displacement of the piston with respect to the time when the piston rod contracts in the drive control circuit of the conventional air cylinder.

FIG. 6 is a pneumatic circuit diagram of a conventional regulating valve.

[Explanation of symbols]

1 ... Air cylinder, 1a ... Head side cylinder chamber, 1b ...
Rod-side cylinder chamber, 2 ... Piston, 4a ... 1st supply / discharge passage, 4b ... 1st supply / discharge passage, 5 ... Direction switching valve, 8 ... Throttle valve, 10 ... Flow control valve, 10a ... Flow control valve main body, 11
... Relief valve, 12 ... Throttle valve, 13 ... Check valve, 14 ... First port, 16 ... First main line, 17 ... Second port, 18
... second main pipeline, 19 ... partition wall, 20 ... first passage, 21 ... second passage, 22 ... third passage, 23 ... valve seat, 37 ... diaphragm, 39 ... spring, 41 ... adjustment shaft.

Claims (2)

[Claims] 1. A piston (2) in an air cylinder (1).
The two chambers (1a, 1b) partitioned by and the direction switching valve (5) are connected to each other through the supply / discharge passages (4a, 4b),
A throttle valve (8, 1) is provided in each supply / discharge passage (4a, 4b).
In the air cylinder drive control circuit provided with 2), in each of the supply / discharge passages (4a, 4b), when the air supply side is set by the switching of the direction switching valve (5), it is in the forward direction, and when it is the air discharge side. Check valve (9,
13) is connected in parallel to the throttle valves (8, 12), and a relief valve (11) is provided in at least one of the supply / discharge passages, in which a pressure upstream of the throttle valve is set as a relief pressure. An air cylinder drive control circuit characterized by being connected to. 2. The valve main body (10a) has one supply / discharge port (14, 17), respectively, and forms a first main pipe line (16) and a second main pipe line (18) with a partition wall (19) interposed therebetween. Then, the partition wall (19) is formed with a first passage (20) and a second passage (21) communicating the both pipelines (16, 18), and the first main passage (18) side is provided with a first passage. A flow control valve having a needle valve (12) inserted into the opening of the passage (20) and a check valve (13) for opening and closing the second passage (21). A third passage (22) communicating with both pipes (16, 18) is formed in (19), a valve seat (23) is provided in the third passage (22), and an elastic member (39) is provided. Diaphragm which is elastically supported and opens and closes the valve seat (23) against the elastic force thereof in accordance with the pressure in the second main pipeline (18). Flow control valve, wherein a 7) provided on the second main conduit (18).