JP3294962B2 - Vacuum valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum valve for preventing trouble caused by rapid exhaust of gas in a vacuum chamber.

[0002]

2. Description of the Related Art A pump port connected to a vacuum pump, a chamber port connected to a vacuum chamber, a valve seat in a flow path connecting these ports, a valve body for opening and closing the valve seat, The vacuum valve provided with a drive unit for the valve body,
When there is a large amount of air in the vacuum chamber, a large amount of air is temporarily discharged to the pump port when the valve element opens the valve seat, so that the air in the vacuum chamber is disturbed, and the air in the vacuum chamber is disturbed. Since dust for the reaction product flies up and hinders subsequent operations, it is necessary to provide a means for preventing rapid exhaust of air.

To solve this problem, Japanese Patent Application No. 5-73132 proposes a vacuum valve having a mechanism for preventing rapid exhaust of gas in a vacuum chamber. This proposed vacuum valve has the advantage that it can prevent troubles due to rapid evacuation of the gas in the vacuum chamber and can cut off the communication between the ports regardless of the operation of the vacuum pump. ing. However, in the above-described vacuum valve, since the opening and closing stroke of the main valve seat by the main valve body and the opening and closing stroke of the bypass valve seat by the bypass valve body are in series, these strokes are added to make the valve large. In addition, since the drive unit that opens and closes the main valve body is mounted above the bonnet, the entire valve becomes large, which increases the cost.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small, inexpensive vacuum valve free from troubles caused by rapid exhaust.

[0005]

In order to solve the above-mentioned problems, the present invention provides a pump port connected to a vacuum source, a chamber port connected to a vacuum chamber, and a valve in a flow path connecting these ports. A vacuum valve including a body having a seat, a valve body for opening and closing the valve seat, a driving unit for the valve body, and a flow path switching mechanism for switching and communicating the flow path between a throttled state and a fully opened state. The drive unit includes a pressure receiving body that hermetically partitions a cylinder chamber to which the pressure fluid is supplied and discharged from a breathing chamber that opens to the atmosphere, and the flow path switching mechanism supplies the pressure fluid that communicates with the cylinder chamber. A passage, a bypass thereof, a flow path switching member that moves integrally with the pressure receiving body to switch the supply path between direct communication and communication by a bypass, and a direction of movement of the pressure receiving body depending on the magnitude of the pressure of the chamber port. straight A pressure action chamber that moves in the same direction, and a poppet-type pressure adjustment valve that moves in the same direction to open and close the bypass. When the pressure in the chamber port is high, the pressure adjustment valve closes the bypass and The flow path switching member shuts off the direct communication of the supply path, thereby stopping the valve body in the middle of movement and communicating the flow path in a throttled state, and when the pressure of the chamber port decreases, the pressure regulating valve opens the bypass. The supply path is communicated by a bypass so that the valve body communicates the flow path in a fully open state.

Further, in order to solve the same problem, the present invention is characterized in that the set pressure of the pressure adjusting valve in the vacuum valve can be adjusted.

Further, in order to solve the same problem, a flow path switching member in these vacuum valves is mounted so as to be capable of moving forward and backward with respect to the pressure receiving body.

[0008]

When the valve body closes the valve seat, the communication between the pump port and the chamber port is interrupted. Therefore, even if the pump port is connected to the vacuum source, the gas in the chamber port is not exhausted. In this case, since the pressure receiving member and the flow path switching member move in the closing direction of the valve seat, the supply path is in direct communication. In addition, since the pressure in the chamber port is high, the pressure action chamber and the pressure regulating valve that moves in the moving direction close the bypass.

When the pressure fluid is supplied from the supply passage to the cylinder chamber, the pressure receiving member and the flow path switching member move in the opening direction of the valve seat, and the valve body moves in the opening direction of the flow path. And keeps closed. When the pressure receiving member and the flow path switching member move by a predetermined stroke, the flow path switching member cuts off the direct communication of the supply path, so that the supply of the pressurized fluid to the cylinder chamber is cut off and these movements are stopped. The valve element communicates the flow path in a throttled state. Therefore, the gas in the chamber port is exhausted to the pump port with the amount of exhaust restricted by the valve element in the throttled state, so that the gas in the chamber port is not rapidly exhausted. In this case, the throttle opening degree of the flow path by the valve body is determined by the stroke until the flow path switching member cuts off the direct communication with the supply path.

When the pressure in the chamber port decreases to a level at which dust does not rise in the vacuum chamber, the pressure regulating valve opens the bypass, and pressurized fluid is supplied to the cylinder chamber from the supply passage communicating via the bypass. Therefore, the pressure receiving member, the flow path switching member, and the valve element gradually move in the opening direction of the flow path to make the flow path communicate with the fully opened state. In this case, the gas is not rapidly exhausted because the pressure in the chamber port and the vacuum chamber is reduced.
When the pressure fluid in the cylinder chamber is discharged, the drive unit returns, the valve body closes the valve seat, the pressure receiving body and the flow path switching member return to the original state, and when the pressure in the vacuum chamber becomes atmospheric pressure, When the pressure action chamber returns to the original state, the pressure regulating valve closes the bypass and prepares for the next exhaust.

Since the pressure action chamber is displaced by the pressure difference between the pressure of the chamber port and the atmospheric pressure, it is not affected by the line resistance between the pump port and the vacuum source. Accurately responds to chamber port pressure when entering a state. In this case, by adjusting the set pressure of the pressure adjusting valve, it is possible to adjust the pressure of the chamber port when the valve element makes the flow path fully open. Further, when the flow path switching member is moved forward and backward with respect to the pressure receiving body, it is possible to adjust a stroke until the flow path switching member cuts off the direct communication with the supply path, and thereby, the opening degree of the flow path by the valve element is reduced. Can be adjusted.

[0012]

1 shows an embodiment of the present invention. This vacuum valve comprises a body 1, a bonnet 2, a cover 3 thereof, and a drive unit 4 (pneumatic cylinder in the illustrated example) incorporated in the bonnet 2. And a flow path switching mechanism 5 incorporated in the cover 3. The body 1 has a pump port 6 connected to a vacuum source (not shown) such as a vacuum pump, and a chamber connected to a vacuum chamber (not shown). A port 7 is formed, and a valve seat 9 facing the drive unit 4 is formed in a flow path 8 of the body 1 that connects the ports 6 and 7.

The valve body 11 for opening and closing the valve seat 9 is provided with a valve seat 9.
Plate 11 on which a valve member 12 for sealing airtight is mounted.
a and a shaft 11 b, and a tip of the shaft 11 b that penetrates the hood 2 airtightly is attached to a piston 13 that constitutes a pressure receiving body in the drive unit 4. An outer peripheral edge of a metal plate 15 is hermetically sandwiched between the body 1 and the bonnet 2, and both ends of a metal bellows 16 are hermetically fixed to an inner peripheral edge of the metal plate 15 and the seal plate 11a. A return spring 17 of the valve element 11 is contracted in a space which is airtightly partitioned by 16.

A switching channel 19 is formed in the cover 3 so as to penetrate in the axial direction. An external opening of the switching channel 19 is closed by a plug 20. The inside of the bonnet 2 is partitioned by the piston 13 into a cylinder chamber 21 on the body 1 side and a breathing chamber 22 in which the switching flow path 19 is opened.
The breathing chamber 22 communicates with the cylinder chamber 21 through a second supply passage 25 provided in the hood 2 and the cover 3, and the breathing chamber 22 communicates with the outside through a breathing port 26. In the switching flow path 19, a first seal ring 27 is provided on the respiratory chamber 22 side from the second supply path 25, and a second seal ring 28 is provided between the supply paths 23 and 25 (both of these seal rings are O-rings). Are fitted respectively.

The flow path switching mechanism 5 shown in detail in FIG.
One end is provided on the side surface of the cover 3 and has a concave portion 30 which is gradually reduced in diameter toward the switching flow channel 19, and a partition plate 31 for airtightly partitioning the concave portion between the opening side and the switching flow channel side is fitted in the concave portion 30. The opening of the recess 30 is closed by a closing member 32. The room between the partition plate 31 and the closing member 32 is partitioned into a pressure action chamber 34 and an atmospheric pressure chamber 35 by a diaphragm 33 whose peripheral edge is hermetically fixed to the inner surface of the recess 30, and the pressure action chamber 34 The communication passage 36 formed in the bonnet 2 and the metal plate 15 communicates with the chamber port 7, and the atmospheric pressure chamber 35 communicates with the outside through a breathing hole 37.

An adjusting screw 39 is screwed to the closing member 32 so as to be able to advance and retreat, and a pressure adjusting spring 4 is provided between an adjusting seat 40 attached to the tip of the adjusting screw 39 and the diaphragm 33.
1 is contracted. On the other hand, the valve chamber 42 behind the partition member 31 includes a first bypass 43 opening to the switching flow path 19 on the upstream side of the seal ring 28, and a seal ring 27.
And a second bypass 44 that opens into the switching flow path 19 between the switching flow path 19 and the distal end of the flow path switching member 45 whose base is screwed to the piston 13 so as to be able to advance and retreat. The outer peripheral surface can be hermetically sealed by seal rings 27 and 28.

The diaphragm 33 has a valve rod 47 which penetrates the partition plate 31 in an airtight manner, protrudes into the valve chamber 42 and is displaced integrally with the diaphragm, and a poppet which opens and closes the first bypass 43 at the tip of the valve rod 47. A pressure regulating valve 48 of the form is mounted. The port 24 is connected to a three-port solenoid valve 49 for supplying and discharging compressed air to and from the cylinder chamber 21.

FIG. 1 shows that the air in the cylinder chamber 21 is supplied to the port 2.
The state is discharged from the 4-port and 3-port solenoid valves 49 and the inside of the vacuum chamber is at atmospheric pressure. In this case, the valve element 11 moves downward in the figure by the urging force of the return spring 17 to close the valve seat 9, and the pressure adjusting valve 48 closes the first bypass 43 by the urging force of the pressure adjusting spring 41. . Therefore, the flow path switching member 4 that moves integrally with the piston 13
5 is inserted into the first seal ring 27 and the switching flow path 19
The communication between the first supply passage 23 and the second
The supply channel 25 is in direct communication with the switching channel 19.
Since the pressures in the pressure adjustment chamber 34 and the atmospheric pressure chamber 35 are substantially equal, the pressure adjustment valve 48 closes the first bypass 43 by the urging force of the pressure adjustment spring 41. In this state, the communication between the pump port 6 and the chamber port 7 is blocked by the valve body 11, so that the air in the chamber port 7 is not discharged even when the vacuum pump is operated.

When compressed air is supplied from the solenoid valve 49 to the port 24, compressed air is supplied to the cylinder chamber 21 through the supply paths 23 and 25, and the piston 13 and the flow path switching member 45 are supplied.
Moves upward in the figure, and when the flow path switching member 45 is inserted into the second seal ring 28, the direct communication between the supply paths 23 and 25 is cut off. In this case, although the first supply path 23 and the first bypass 43 communicate with each other (see FIG. 2), since the bypass 43 is closed by the pressure regulating valve 48 (see FIG. 3), the compression to the cylinder chamber 21 is performed. The air supply is shut off. Therefore, the piston 13 stops after a stroke corresponding to the amount of air supplied to the cylinder chamber 21, whereby the valve element 11 opens the flow path 8 in a throttled state, so that the air in the chamber port 6 is gradually discharged. . In this case, the valve element 1
The throttle opening degree of the flow path 8 by 1 is substantially equal to the stroke until the flow path switching member 45 cuts off the communication between the supply paths 23 and 25. Therefore, by moving the flow path switching member 45 forward and backward with respect to the piston 13 via the switching flow path 19, it is possible to adjust the throttle opening of the flow path 8 by the valve element 11.

When the pressure in the chamber port 7 is reduced to a pressure (x in FIG. 4) at which the air in the vacuum chamber does not rise due to the exhaust from the pump port 6, the communication path 36
As a result, the air pressure in the pressure action chamber 34 communicating with the chamber port 7 is reduced, and the acting force of the differential pressure between the pressure action chamber 34 and the atmospheric pressure chamber 35 acting opposite to the diaphragm 33 is reduced by the urging force of the pressure adjusting spring 41. When the pressure becomes larger, the diaphragm 33 is displaced toward the pressure action chamber 34 against the urging force of the pressure adjusting spring 34, and the pressure adjusting valve 48 gradually opens the first bypass 43.

When the pressure regulating valve 48 opens the bypass 43, the supply passages 23 and 25 are connected to the bypasses 43 and 44 and the valve chamber 4.
2 and the compressed air is supplied to the cylinder chamber 21, so that the piston 13 and the valve element 11 gradually move upward, and the flow path 8 is fully opened. In this case, since the pressure in the chamber port 7 has decreased, the air in the vacuum chamber is not rapidly exhausted. Further, the pressure of the chamber port 7 when the valve element 11 makes the flow path 8 fully open is
The adjustment can be performed by moving the adjusting screw 39 from the outside of the cover 3 to the closing member 32 and adjusting the urging force of the pressure adjusting spring 41.

When the three-port solenoid valve 49 is switched to discharge the compressed air in the cylinder chamber 21, the urging force of the return spring 17 causes the valve body 11 and the piston 13 to move downward in the drawing.
The valve body 11 closes the valve seat 9. In this case, the piston 13
At the beginning of the downward movement, the supply paths 23 and 25 are communicated by the flow path switching member 45 via the bypasses 43 and 44, and when the flow path switching member 45 continues to descend, the supply paths 23 and 25 are connected via the switching flow path 19. To communicate directly. When the inside of the vacuum chamber is returned to the atmospheric pressure by the end of the operation, the pressure action chamber 34
Is brought to the atmospheric pressure, the diaphragm 33 returns to the state of FIG. 1 by the urging force of the pressure adjusting spring 41, and the pressure adjusting valve 48 closes the first bypass 43 to prepare for the next operation.

In the above embodiment, since the pressure regulating valve 48 moves in a direction substantially perpendicular to the moving direction of the piston 13 to open and close the first bypass 43, the stroke of the valve body and the stroke of the bypass valve body are connected in series. Since the entire stroke can be shortened as compared with the case where the vacuum valve is used, the vacuum valve can be made small and inexpensive. Further, since the compressed air is supplied to the bypass 43 and the pressure regulating valve 48 is formed in a poppet shape, a large amount of air can be supplied to the cylinder chamber 21 even if the stroke of the pressure regulating valve 48 is small. Thus, the vacuum valve can be made compact.

Further, unlike the case where the pressure action chamber 24 is provided in the piston 13 or incorporated in the valve body 11, the pressure regulating valve 48 is provided with a plurality of valves having different valve seat diameters and different valve stroke lengths. Since the number of parts can be reduced because the same type of body can be used, the vacuum valve can be made inexpensive. Further, since the diaphragm 33 that partitions the pressure action chamber 34 is displaced by the differential pressure between the pressure of the chamber port 7 and the atmospheric pressure, the valve 33 is displaced by a difference in pressure due to the differential pressure between the chamber port 7 and the pump port 6. The body 11 accurately responds to the seven pressures at the chamber ports when the flow path 8 is fully open.

[0025]

According to the vacuum valve of the present invention, a separate throttle member is provided by switching the flow path between the communication in the throttled state and the communication in the fully opened state by moving the valve body that opens and closes the valve seat. Since there is no need, the structure of the flow path is simple and the vacuum valve can be inexpensive. Further, since the pressure adjusting valve can be used in common for a plurality of types of valve bodies, the number of parts is reduced, and thus the vacuum valve can be made inexpensive. Further, since the stroke of the valve element and the stroke of the pressure action chamber for opening and closing the bypass and the stroke of the pressure regulating valve are substantially orthogonal, the size of the vacuum valve can be reduced as a whole.

Further, by adjusting the set pressure of the pressure adjusting valve, the pressure of the chamber port when the valve element fully opens the flow path can be adjusted. By moving the flow path back and forth, the throttle opening of the flow path can be changed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment.

FIG. 2 is an explanatory diagram of a switching channel and a channel switching member.

FIG. 3 is an enlarged view of a pressure adjusting mechanism.

FIG. 4 is a diagram showing the opening degree and pressure of a valve seat.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 4 Drive part 5 Flow-path switching mechanism 6 Pump port 7 Chamber port 8 Flow path 9 Valve seat 11 Valve 13 Piston 21 Cylinder chamber 22 Respiration chamber 23, 25 Supply path 34 Pressure action chamber 35 Atmospheric pressure chamber 43, 44 Bypass 45 flow path switching member 48 pressure regulating valve

Claims (3)

(57) [Claims] 1. A body having a pump port connected to a vacuum source, a chamber port connected to a vacuum chamber, and a valve seat in a flow path connecting these ports, and a valve body for opening and closing the valve seat. A vacuum chamber provided with a drive unit for the valve body and a flow path switching mechanism for communicating the flow path by switching the flow path between a throttled state and a fully opened state, wherein the drive unit is configured to supply and discharge a pressure fluid. And a pressure receiving body that hermetically partitions a breathing chamber that opens to the atmosphere, wherein the flow path switching mechanism moves integrally with the pressure fluid supply path communicating with the cylinder chamber, a bypass thereof, and the pressure receiving body. A flow path switching member that switches the supply path between direct communication and communication by bypass; a pressure action chamber that moves in a direction substantially perpendicular to the direction in which the pressure receiving member moves according to the magnitude of the pressure in the chamber port; To And a poppet-type pressure regulating valve that opens and closes the bypass by moving the valve. When the pressure in the chamber port is high, the pressure regulating valve closes the bypass and the flow path switching member shuts off the direct communication with the supply path. When the pressure of the chamber port decreases, the pressure regulating valve opens the bypass and connects the supply path by the bypass, and the valve element stops the valve body in the middle of the movement and communicates in a throttled state. Characterized in that the valve is fully open. 2. The vacuum valve according to claim 1, wherein the set pressure of the pressure adjusting valve is adjustable. 3. The vacuum valve according to claim 1, wherein the flow path switching member is attached to the pressure receiving member so as to be able to advance and retreat.