JPH034870Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a vacuum pressure control valve used when vacuum pressure is used to attract and release objects.

[Conventional technology]

Conventionally, as shown in FIG. 3, two solenoid valves 1 and 2 are used as vacuum pressure control valves when vacuum pressure is used to attract and release articles. is constituted by a two-port valve having a port communicating with the suction pad 3 and a port communicating with a vacuum source 4 such as a vacuum pump, or a pressurized air source 5 such as a compressor or air receiver.

In such a vacuum pressure control valve, when the solenoid a of the electromagnetic valve 1 is energized in the illustrated inactive state, the suction pad 3 communicates with the vacuum source 4, so that the desired article can be suctioned and held by the vacuum pressure. can. Further, when the solenoid a is de-energized and the solenoid b of the solenoid valve 2 is energized, the suction pad 3 is communicated with the pressure air source 5, so that the vacuum pressure of the suction pad 3 is eliminated by the pressurized air. The adsorbed items are released.

However, in the conventional vacuum pressure control valve described above, when the vacuum pressure is applied to the suction pad 3 to attract and hold the article, if the solenoid a of the solenoid valve 1 is demagnetized due to a power outage, etc., the suction pad 3 and the vacuum source 4 are cut off, the suction pad 3 loses its ability to suction and hold the article, potentially causing a serious accident. Furthermore, if the operations of the solenoid valves overlap when the solenoids a and b are switched between energization and de-excitation, the pressure air source 5 and the vacuum source 4 will be short-circuited, and the air in the pressure air source 5 will flow directly into the vacuum source 4. There are also drawbacks.

In order to eliminate the drawbacks of the vacuum pressure control valve described above, the directional control valve 14 is operated by two 3-port pilot valves 11 and 12 that supply and discharge pilot fluid, as shown in FIG. A vacuum pressure control valve may be considered in which the pilot valve 12 is provided with a detent mechanism 15 for holding the switching position and a solenoid c for releasing the lock of the detent mechanism 15.

In this vacuum pressure control valve, pilot valve 1
Each of the solenoids a, b, and c in the valves 1 and 12 is de-energized, and the pilot chambers at both ends of the directional control valve 14 are opened to the atmosphere through the pilot valves 11 and 12.
As a result, when the switching valve 14 is in the neutral position shown, the ports communicating with the suction pad 3, the vacuum source 4, and the pressure air source 5 are all closed, so the operation of the suction pad 3 is stopped. ing.

When solenoid b is energized in this state, pilot fluid from the pressure air source 5 flows into the pilot valve 12.
Since the suction pad 3 is supplied to the pilot chamber on the left side of the switching valve 14 through the switching valve 14, the suction pad 3 is communicated with the vacuum source 4 by switching the switching valve 14.

In this switching state, the pilot valve 12 is held in this state by the detent mechanism 15.
Even if the solenoid b is demagnetized due to a power outage or the like while the suction pad 3 is suctioning and holding an article, the suction pad 3 will not lose its ability to suction and hold the article.

Next, when the solenoid c is energized, the position holding by the detent mechanism 15 is released and the pilot valve 12 returns to the state shown in the figure, and the pilot fluid in the pilot chamber on the left side of the switching valve 14 is discharged to the atmosphere, so that the switching The valve 14 is returned to the illustrated neutral position by the biasing force of the spring.

Thereafter, when the solenoid a of the pilot valve 11 is energized, pilot fluid is supplied to the pilot chamber on the right side of the switching valve 14.
moves to the left and the suction pad 3 is communicated with the pressurized air source 5, so that the article suctioned and held by the suction pad 3 is released. Next, when the solenoid a is de-energized, the pilot fluid in the pilot chamber on the right side of the switching valve 14 is discharged to the atmosphere through the pilot valve 11, so the switching valve 14 is moved to the neutral position shown in the figure by the biasing force of the spring. The suction pad returns to its resting state.

The vacuum pressure control valve passes through a neutral position where all ports communicating with the suction pad 3 and the vacuum source 4 or the pressure air source 5 are shut off when switching the communication between the suction pad 3 and the vacuum source 4 or the pressure air source 5 in the directional switching valve 14, 5
It is possible to prevent air from the pressurized air source 5 from flowing directly into the vacuum source 4 due to a short circuit between the air source and the vacuum source 4.

However, in general, the operation of the suction pad that suctions and releases an article does not require a resting state between suctioning and holding the article and releasing it, although it requires a resting state between releasing the article and suctioning and holding the article. The vacuum pressure control valve described above has the disadvantage that it is wasteful in operation and is expensive since it requires a separate solenoid c for the pilot valve 12.

[Problem that the invention attempts to solve]

With this invention, even if the pilot valve loses its valve function due to a power outage, etc., the suction pad's suction holding function will not be lost, there will be no short circuit between the pressure air source and the vacuum source, and there will be no unnecessary operation. The problem to be solved is to obtain an inexpensive vacuum pressure control valve.

[Means for solving problems]

The present invention has a first switching position in which the output port communicating with the suction pad is communicated with the vacuum pressure port communicating with the vacuum source using pilot fluid pressure supplied to and discharged from the pilot chambers at both ends, and a first switching position in which the output port communicates with the vacuum pressure port communicating with the vacuum source. a valve member that is driven to switch to a second switching position communicating with a pressure port that communicates with a pressure source and closing between the ports in a neutral position; In a certain state, the fluid pressure of the pressure port is introduced into one pilot chamber to maintain the switching position, and the other pilot chamber is supplied with pilot fluid to release the holding. In this way, a detent mechanism using fluid pressure is constructed, and both of the above problems are solved.

[Effect]

When both pilot valves are de-energized and the directional control valve is in the neutral position, when one pilot valve is energized and pressurized air is supplied to the other pilot valve, the valve member moves to the first control position. The output port and the vacuum pressure port communicate with each other, and at the same time, the pressure port communicates with the pilot chamber. As a result, vacuum pressure is applied to the suction pad communicating with the output port, and the switching state is maintained by the pressure fluid supplied to one pilot chamber. Therefore, even if the pilot valve loses its valve function due to a power outage or the like in this state, the switching valve is maintained at the first switching position by the pilot fluid pressure.

Next, when the pilot valve is de-energized and the other pilot valve is energized, pilot fluid pressure is supplied to the other pilot chamber, so the valve member slides toward the neutral position, and the valve member slides toward the neutral position. The fluid pressure in one of the pilot chambers, which had been supplied with fluid pressure, rapidly decreased.
The valve member passes through the neutral position and immediately switches into the second switching position. In this case, the valve member passes through a neutral position in which each port is closed, so that there is no short circuit between the compressed air source and the vacuum source.

In the second switching position, the pressure port and the output port communicate with each other, so that pressurized air is supplied to the suction pad that communicates with the output port, and the suction of the article is released. This release of suction is performed without going through a rest state after the article is suctioned and held, so there is no waste in the operation of the vacuum pressure control valve.

Further, when the pilot valve is de-energized, the valve member returns to the neutral position.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and this vacuum pressure control valve includes a fluid pressure-operated directional control valve 2 and first and second control valves for supplying and discharging pilot fluid to and from the directional control valve 20.
It is equipped with pilot valves 21 and 22.

A spool 25, which is an example of a valve member, is slidably inserted into a through hole bored in the body 24 of the switching valve 20, and a first pilot chamber 26 and a return spring chamber 27 are provided at one end of the through hole. A second pilot chamber 28 is provided at the other end. The body 24 also has a pressure port 30 communicating with the pressure air source 5, a pilot port 31 communicating with the first pilot chamber 26 on both sides thereof, an output port 32 communicating with the suction pad 3, and a pressure port 30 communicating with the atmosphere on both sides thereof. A communicating exhaust port 33 and a vacuum pressure port 34 communicating with the vacuum source 4 are respectively opened.

One end of the spool 25 is connected to the return spring chamber 2.
7 to the first pilot chamber 26, and the other end to the second pilot chamber 26.
The first piston 36 and the second piston 37 respectively protrude into the pilot chamber 28, and their tips are slidably inserted into the pilot chambers 26, 28.
is in contact with.

The spool 25 also has a return spring chamber 27.
A compressed spring 39 is inserted between the spring receivers 38, 38 which are slidably inserted into the small diameter portion.
The spring receivers 38, 38 are formed in such a way that they are brought into contact with both ends of the small diameter portion of the spool 25 by the biasing force of the spool 25, and at the same time, the spring receivers 38, 38 are also brought into contact with both end walls of the return spring chamber 27 when the spool 25 is in its neutral position. There is.

In the first switching position where pilot fluid is supplied to the first pilot chamber 26, the spool 25 connects the output port 32 and the vacuum pressure port 34, and the pilot port 31 and the pressure port 30, and closes the exhaust port 33. However, in the second switching position where the pilot fluid is supplied to the second pilot chamber 28, the output port 32 and the pressure port 30, and the pilot port 31 and the exhaust port 3
3 and closes the vacuum pressure port 34, and in the neutral position, the pilot port 31
The exhaust port 33 is communicated with the exhaust port 33 with a small opening amount, and the other ports 30, 32, and 34 are closed.

Further, the first pilot valve 21 connects the pressure air source 5 and the first pilot chamber 26 when the solenoid a is energized, and communicates the pressure air source 5 and the first pilot chamber 26 when the solenoid a is deenergized. 26
On the other hand, the second pilot chamber 22
When the solenoid b is energized, the pressure air source 5 and the second pilot chamber 28 are communicated with each other, and when the solenoid b is de-energized, the second pilot chamber 28 is communicated with the atmosphere.

Next, the operation of the above embodiment will be explained with reference to FIGS. 1 and 2.

In FIG. 1, the solenoids a and b of the pilot valves 21 and 22 are in a de-energized state, and the pilot fluid in the first pilot chamber 26 is flowing through the pilot port 31.
Since the pilot fluid in the second pilot chamber 28 is discharged through the second pilot valve 22, the spool 2
5 is in the neutral position due to the biasing force of the return spring 39. Therefore, the pressure port 30, the output port 31, and the vacuum pressure port 34 are all closed, and the suction pad 3 is in a rest state.

In this state, when the solenoid a of the first pilot valve 21 is excited, the pressurized air from the pressure air source 5 passes through the first pilot valve 21 and enters the first pilot chamber 2.
6, the first piston 36 presses the spool 25, and the spool 25 slides to the left in the figure while compressing the spring 39 on one side of the spring receiver 38. In this case, since the pilot port 31 and the exhaust port 33 are in communication, a part of the pilot fluid supplied to the first pilot chamber 26 flows out to the atmosphere through the exhaust port 33, but the spool is not in the neutral position. In some cases, the opening amount of the exhaust port 33 is small and the spool 25
Since the exhaust port 33 is closed at the beginning of sliding to the left, only a small amount of pilot fluid flows out into the atmosphere.

When the spool 25 slides to the left in the figure and the switching valve 20 switches to the first switching position, the output port 32, the vacuum pressure port 34, and the pressure port 30
and the pilot port 31 communicate with each other. For this reason,
Vacuum pressure from a vacuum source 4 acts on the suction pad 3, and the desired article is suctioned and held by the suction pad 3. Furthermore, air from the pressurized air source 5 is supplied to the first pilot chamber 26 through the pressure port 30 and the pilot port 31, and the first switching position is maintained by this air pressure, so that the suction pad 3 Solenoid a may be damaged due to a power outage while holding the
Even if the first pilot valve 21 loses its valve function due to demagnetization, the suction holding power of the suction pad 3 will not be lost.

That is, the mechanism that temporarily holds the spool in the first switching position by supplying pressure fluid from the pressure port 30 to the first pilot chamber 26 through the pilot port 31 constitutes a detent mechanism that utilizes fluid pressure. It turns out.

Next, when the solenoid a is de-energized and the solenoid b of the second pilot valve 22 is energized, pressurized air from the pressurized air source 5 is supplied to the second pilot chamber 28 .
Since the pilot fluid pressures of 6 and 28 are equal,
The spool 25 slides to the right in the figure due to the biasing force of the compressed return spring 39. As a result, when the spool 25 reaches the neutral position, the pilot port 31 and the exhaust port 33 communicate with each other, and the pilot fluid pressure in the first pilot chamber 26 decreases rapidly. The pressure causes the switch to pass through the neutral position and switch to the second switching position while compressing the return spring 39.

In this switching operation, when the spool 25 passes through the neutral position, the pressure port 30, the output port 32, and the vacuum pressure port 34 are all temporarily closed, so that the pressure air source 5 and the vacuum source 4 are short-circuited. This prevents the compressed air from the compressed air source 5 from flowing directly into the vacuum source 4.

When the spool 25 switches to the second switching position,
The pressure port 30 and the output port 32 are in communication, the pilot port 31 and the exhaust port 33 are in communication, and the vacuum pressure port 34 continues to be closed. Therefore, the adsorption of the article is released. Since this suction is released without going through a rest state after the article is suctioned and held, there is no waste in the operation of the vacuum pressure control valve.

Next, solenoid b of the second pilot valve 22
When the excitation is released, the pressure in the second pilot chamber 28 drops to atmospheric pressure, so the spool 25 slides to the right by the biasing force of the return spring 39 and returns to the neutral position shown.

[Effect of idea]

In the present invention, when the suction pad is suctioning and holding a desired article, the switching position of the valve member is maintained by a detent mechanism using fluid pressure, so that the pilot valve that switches the valve member can be operated in the event of a power outage, etc. Even if the valve function is lost due to demagnetization, the ability of the suction pad to attract and hold articles will not be lost. Further, the output port is a first port communicating with the vacuum pressure port.
When switching between the switching position and the second switching position communicating with the pressure port, the ports pass through a neutral position where they are closed, so the pressure port and the vacuum port are short-circuited and the air from the pressurized air source is Not only can leakage directly to the vacuum source be prevented, but also unnecessary operations can be avoided since the valve member does not stop at the neutral position during the switching.

Furthermore, since the switching of the directional control valve and the maintenance and release of the above-mentioned switching state are performed using pilot fluid pressure, not only can the solenoid be made smaller, but also the solenoid can be used to release the lock of the mechanical detent mechanism and the detent mechanism. etc., the vacuum pressure control valve can be made simple and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation as above, Fig. 3 is an explanatory diagram of the operation of a conventional control valve, and Fig. 4 is an explanatory diagram of the operation of the prior art of the present invention. It is. 3... Suction pad, 4... Vacuum source, 5... Pressure air source, 20... Directional switching valve, 21, 22... Pilot valve, 26, 28... Pilot chamber, 30
...Pressure port, 32...Output port, 34...
Vacuum pressure port.

Claims (1)

[Scope of utility model registration request] A first switching position in which the output port communicating with the suction pad is communicated with a vacuum pressure port communicating with a vacuum source, and the output port is communicated with a source of pressurized air using pilot fluid pressure supplied to and discharged from the pilot chambers at both ends. a valve member that is driven to switch to a second switching position that communicates with the pressure port and closes between the ports in a neutral position;
While it is in the first switching position, the fluid pressure of the pressure port is introduced into one pilot chamber to maintain that switching position, and the holding is released by supplying pilot fluid to the other pilot chamber. A vacuum pressure control valve characterized in that a flow path is provided, thereby forming a detent mechanism using fluid pressure.