JPS608161Y2 - flow control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow control valve mainly used to control the driving speed of a pneumatic cylinder.

Conventionally, in order to reduce the driving speed of a pneumatic cylinder midway through its stroke, a combination of two speed control valves and one direction control valve is often used in the pneumatic circuit.

FIG. 1 shows an example of this, in which the connection of the pneumatic cylinder 1 to the high-pressure air source 3 is switched by the main directional control valve 2, and the rod 1a is reciprocated.

In this pneumatic circuit, when the main directional control valve 2 is switched from the position shown in FIG. 1 to drive the pneumatic cylinder 1, the flow rate of the rod side passage 4 is set by the throttle 5a of the speed control valve 5, The rod 1a is driven at an initial speed corresponding to this.

When the directional control valve 6 is switched in the middle of this stroke, the speed control valve 7 is connected to the rod side flow path 4, and the effective cross-sectional area of the throttle 7a of the speed control valve 7 is changed from that of the throttle 5a of the speed control valve 5. Since it is set smaller than that, the flow rate of the rod-side flow path 4 is further reduced by this throttle 7a, and the pneumatic cylinder 1 performs a deceleration operation.

In addition, when switching the main directional control valve 2 to the state shown in FIG. 1 and returning the pneumatic cylinder 1, the head side flow path 8
The flow rate is set by the throttle 9a of the speed control valve 9, and the rod 1a returns at a speed corresponding to the throttle.

When reducing the driving speed of a pneumatic cylinder using such a pneumatic circuit, if a speed change with a relatively large speed change is performed, the transitional movement will lose smoothness, especially when driving a pneumatic cylinder located vertically. It bounces (or sometimes vibrates) when it is being used.

The present invention has been developed in view of these points, and is designed to slow down the transient movement of the pneumatic cylinder when switching from the initial speed to the deceleration speed, thereby preventing vibration of the pneumatic cylinder, and is compact. The present invention aims to provide a flow control valve that is easy to handle.

In order to solve the above problems, in the present invention, a flow path leading to the first port and a second port are provided inside a valve body having a first port and a second port through which fluid flows in or out. Two channels that communicate with each other are formed into a confluent state, and at the confluence of these channels, the channel that communicates with the first port is selectively communicated with one of the two channels that communicate with the second port. a directional control valve that restricts the flow rate of fluid from the first port toward the directional control valve, but allows fluid to freely flow in the opposite direction;
A velocity control valve is provided in one of the two flow paths leading to the second port to restrict the flow rate of fluid from the directional control valve toward the second port, but to allow fluid to freely flow in the opposite direction. A second speed control valve is provided, and a bypass flow path is provided that bypasses the second speed control valve, and a branch point of the bypass flow path between the second speed control valve and the direction control valve is provided with a bypass flow path that bypasses the second speed control valve. A buffer valve is provided to block the bypass flow path by high pressure air flowing into the pressure chamber behind the valve body from the flow path where the bypass flow path branches through a restriction, and the opening amount of the second speed control valve is adjusted to a second speed control valve. A technical measure has been taken to set the opening amount to be smaller than the opening amount of the speed control valve No. 1.

The above technical means works as follows.

That is, when fluid flows from the first port to the second port, the directional control valve controls the speed of the second of the two flow paths leading to the first port and the second port. If the flow path without a control valve is in communication with each other, the flow rate of the fluid is limited by the first speed control valve in the flow path leading to the first port.

From this state, the flow path is switched by the directional control valve, and the first
Immediately after the communication between the flow path leading to the port and the flow path provided with the second speed control valve, the bypass flow path is opened by the buffer valve, so that the fluid flows through the first speed control valve. The flow rate limited by the speed control valve is maintained, but as time passes, the bypass flow path is gradually closed by the buffer valve, so the flow rate of the fluid gradually approaches the flow rate limit by the second speed control valve, and the bypass flow path is closed. maintains its restricted flow rate after closure.

That is, the fluid flow rate does not suddenly decrease from the restricted flow rate by the first speed control valve to the restricted flow rate by the second speed control valve at the same time as the flow path is switched by the directional control valve, but gradually decreases by the buffer valve. You will be forced to do so.

When fluid flows from the second port to the first port, the fluid is free-flowing in either switching position of the directional control valve.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. In FIG. 2, the valve body 10 includes a first port 11 and a second port 12 through which fluid flows in or out;
The first port 11 is connected to the pneumatic cylinder 1 side of the Rondo side flow path 4 in FIG. 1, and the second port 12 is connected to the main directional control valve 2 side.

Inside the valve body 10, a direction control valve 1 is connected to a flow path 13 leading to the first port 11 via a first speed control valve 14.
5 is disposed, one flow path 16 switched by this directional control valve 25 is directly connected to the second port 12, and the other flow path 17 is connected to a buffer valve 18 and a second speed control valve 19. It communicates with the second port 12 through the port.

The first speed control valve 14 provided in the middle of the flow path 13 is
The flow rate of fluid from the port 11 to the directional control valve 15 is restricted, and the fluid is allowed to freely flow in the opposite direction.
A throttle valve seat 20 is formed in the middle of the flow path 13, and the throttle valve seat 2
A valve body 21 that adjusts its opening amount by moving toward and away from the throttle valve seat 20 is slidably disposed in a valve support hole 22 provided on the first port 11 side of the throttle valve seat 20. The valve body 21 is communicated with the flow path 13 through the gap 23 between the valve body 21 and the valve body 10 , and the valve body 21 is biased by a spring 24 compressed between the valve body 21 and the valve support hole 22 . The adjustment element 25 is pressed against the tip of an adjuster 25 which is screwed in so that it can be moved forward and backward from the outside.

In the figure, 25 at 25 b indicates a screw portion and a knob portion of the adjuster 25, 26 indicates a lock nut, and 27 indicates an O-ring.

The direction control valve 15 selectively connects the flow path 13 with one of the pair of flow paths 16 and 17.
6. Valve chamber 2 that communicates with these flow channels at the junction of 17
8, the valve body 29 is slidably inserted in the axial direction.
The valve body 29 is urged in one direction by a spring 30 contracted at one end, and when the valve body 29 is pushed in against the urging force of the spring 30 as shown in FIG. is the flow path 13
．． 16 and closes the valve seat 31 between the passages 13 and 16.
When the flow path 17 is brought into communication with the flow path 17 and the valve body 29 is returned to its original position by the biasing force of the spring 30 as shown in FIG. It is configured to close the flow path and allow the flow path 13 and flow path 16 to communicate with each other.

Note that 33 in the figure indicates an O-ring.

The operating mechanism 34 that drives the valve body 29 of the directional control valve 15 against the biasing force of the spring 30 employs various operating methods such as an electromagnetic operating type, a pneumatic operating type, and a mechanical lever operating type. It is desirable to have a structure in which these operating means can be arbitrarily selected and installed.

The buffer valve 18 provided in one of the flow paths 17 between the direction control valve 15 and the second port 12 is for gently restricting the fluid flow rate by the second speed control valve 19. The valve body 35 is connected between the direction control valve 15 and the second speed control valve 19 to form a flow path 17a passing through the second speed control valve 19 and a bypass flow that bypasses the second speed control valve 19. The valve body 35 is provided at a branch point with the passage 17b, and is configured to open and close the bypass passage 17b, and is brought into contact with and separated from a valve seat 37 provided at a communication port 36 at the branch point of the bypass passage 17b. The valve body 35, which opens and closes, is slidably inserted into the sliding hole 38, and is biased in a direction away from the valve seat 37 by a spring 40 compressed between it and the valve body 10. The pressure chamber 39 is connected to the throttle 41 of the communication passage 41.
a to the flow path 17 on the directional control valve 15 side, and when the pressure in the flow path 17 increases, the pressure chamber 39
The pressure gradually increases, and this pressure causes the valve body 35 to gradually close the valve seat 37 against the biasing force of the spring 40.

Note that the aperture 41a can also be a variable aperture.

Further, numeral 42 in the figure indicates an O-ring that seals the pressure chamber 39.

The second speed control valve 19 limits the flow rate of fluid flowing through the flow path 17 toward the second port 12, and allows fluid to freely flow in the opposite direction. 14
The valve element 45, which has substantially the same configuration as the flow path of the throttle valve seat 44 and which adjusts the opening amount by moving toward and away from the throttle valve seat 44 provided in the communication port 43 at the confluence of the flow paths 17a and 17b, is connected to the flow path of the throttle valve seat 44. 17
It is slidably arranged in a valve support hole 46 provided on the a side, and the valve support hole 46 is connected to the flow path 17 through a gap 47 between the valve body 45 and the valve support hole 46.
a, and biases the valve body 45 with a spring 48 contracted between the valve body 45 and the valve support hole 46. It is pressed against the tip.

This second speed control valve 19 is connected to the first speed control valve 1.
regulator 4 to further restrict the fluid flow rate than regulator 4.
9 is set, but the fluid 17b is communicated with the second port 12 regardless of whether the valve body 45 is operated.

In addition, in the figure, 49a and 49b indicate the screw portion and the knob portion of the adjuster 49, 50 indicates a lock nut, and 51 indicates an O-ring.

FIG. 4 shows the JI flow rate control valve having the above configuration.
This is a circuit diagram mainly coded with the S symbol, with some modifications taken into consideration of effects, and the same reference numerals are given to the same or equal detailed parts as in the above embodiment.

Next, the operation of the flow control valve having the above configuration will be explained.

In the initial speed state shown in FIG. 2, the high pressure air that has flowed into the first port 11 flows into the valve support hole 22 through the gap 23, increases the pressure inside the valve support hole 22, and cooperates with the biasing force of the spring 24. The valve body 21 is pressed against the regulator 25 by the action, so that the flow rate of the high-pressure air is restricted by the speed control valve 14 and flows out from the second port 12 via the direction control valve 15 and the flow path 16.

Here, if the direction control valve 15 is switched as shown in FIG.
The high-pressure air restricted by the speed control valve 14 flows through the flow path 17.
Since the communication port 36 is initially wide open, the high-pressure air flows into the flow path 17b and the second
However, as time passes, the pressure in the pressure chamber 39 increases and the valve body 35 closes the valve seat 37, so the high-pressure air passes through the flow path 17a and flows out from the second speed control valve 19. The fluid is constricted and flows into the flow path 17b through the communication port 43, and flows out through the second port 12.

To explain this in more detail based on the flow rate characteristic diagram in FIG. The outflow amount in the previous state of FIG. 2 is shown.

If the directional control valve 15 is now switched at the time separation □, the valve element 35 will gradually close the valve seat 37 as the internal pressure of the pressure chamber 39 gradually increases. flows into the flow path 17b and directly flows into the second port 12.
The flow rate flowing out from the flow path gradually decreases as shown by the chain line in the figure, and as a result, the flow rate flows from the flow path 17a through the communication port 43 throttled by the valve body 45 of the second speed control valve 19. 17
The flow rate flowing into port b and flowing out from the second port 12 gradually increases as shown by the broken line C in the same figure, and the total flow rate from the second port 12 during this process corresponds to the curve indicated by the solid line a in the figure. As shown in part B, when the valve seat 37 is eventually closed by the valve body 35 at time n, 2, all of the high pressure air in the flow path 17 passes through the communication port 43 restricted by the second speed control valve 19. The liquid flows through the second port 12 and flows out from the second port 12, and the flow rate becomes as shown by the solid straight line portion C in FIG.

When high pressure air is supplied to the second port 12, if the valve body 35 has not completely returned, the high pressure air in the flow path 17b is simultaneously supplied to the flow path 17a from both communication ports 36.43.
The high pressure air passing through the communication port 43 causes the valve body 45 of the second speed control valve 19 to be moved by the spring 48.
The communication port 43 is opened wide by pressing against the urging force of the valve body 35, and after the valve body 35 is completely restored, high-pressure air flows into the flow path 17a from the communication ports 36 and 43 to control the direction. The valve 15 is reached.

Further, when the directional control valve 15 is switched to the state shown in FIG. 2, the high pressure air reaches the directional control valve 15 via the flow path 16.

In these cases, the high pressure air that has passed through the directional control valve 15 then flows into the flow path 13 leading to the first port 11,
The valve body 21 of the first speed control valve 14 is pushed down against the biasing force of the spring 24, and the flow freely flows out from the first port 11 through the wide open throttle valve seat 20.

As described above, according to the flow control valve of the present invention, not only can the flow rate of fluid from the first port to the second port be controlled in two stages, but also the deceleration can be performed gently, and the flow rate of the fluid can be controlled in two stages. It has the advantages of not causing vibration when reducing the drive speed from the cut-off speed to the deceleration speed, and being smaller and extremely easy to handle compared to conventional valves that connect multiple valves with piping. It has a strong effect.

[Brief explanation of the drawing]

Fig. 1 is a drive circuit diagram of a conventional pneumatic cylinder, Figs. 2 and 3 are cross-sectional views of the flow control valve of the present invention, Fig. 4 is a circuit diagram symbolizing its configuration, and Fig. 5 is its circuit diagram. It is a flow characteristic diagram. 10... Valve body, 11... First port, 12... Second port, 13. 16.
17...Flow path, 17a, 17b...Flow path, 14...First speed control valve, 15...
... Direction control valve, 18 ... Buffer valve, 19 ...
... Second speed control valve, 35 ... Valve body, 39
...Pressure chamber, 41a...Aperture.

Claims (1)

[Scope of utility model registration request] A flow path leading to the first port and two flow paths leading to the second port are formed in a valve body having a first port and a second port through which fluid flows in or out so as to merge with each other. A directional control valve is provided at the confluence of these flow paths to selectively communicate the flow path leading to the second port with one of the two flow paths leading to the first port. A first speed control valve that restricts the flow rate of fluid from the first port toward the directional control valve but allows fluid to freely flow in the opposite direction is provided in the flow path leading to the second port, and a first speed control valve is provided in the flow path leading to the second port. A second speed control valve is provided in one of the flow paths for restricting the flow rate of fluid from the directional control valve toward the second port, but allowing fluid to flow freely in the opposite direction;
A bypass flow path is provided to bypass the speed control valve of the second speed control valve.
At the branch point of the bypass flow path between the speed control valve and the direction control valve, the bypass flow is controlled by high pressure air flowing from the flow path where the bypass flow path branches into the pressure chamber behind the valve body via the restriction. A flow rate control valve characterized in that a buffer valve for blocking a passage is provided, and the opening amount of the second speed control valve is set smaller than the opening amount of the first speed control valve.