JPH0124408Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a drive device that operates a two-stage stroke cylinder in two stages.

B. Prior Art For example, when spot welding workpieces using a spot gun, the movable spot electrode performs a two-step motion of a preliminary stroke in which it is sent relatively quickly and a pressurization stroke from the fast-travel end position to the pressure welding position. A two-stage stroke cylinder is used. This two-stage stroke cylinder 1
As shown in FIG. 1, an inner cylinder 3 with an open front end is slidably accommodated in an outer cylinder 2,
Further, the pressure piston 4 is slidably accommodated in the inner cylinder 3, the inner cylinder 3 is moved back and forth within the outer cylinder 2, the pressure piston 4 is moved back and forth within the inner cylinder 3, and the pressure piston 4 is moved back and forth within the inner cylinder 3. The tip of the rod protrudes from the outer cylinder 2, and a spot electrode (not shown) is provided at the tip of the pressure piston 4. And this two-stage stroke cylinder 1
is driven by the piston pressurizing port 5 formed in the outer cylinder 2, the inner cylinder pressurizing port 6, and the return port 7 through 3 ports and 2 positions of the first, second, and third ports, respectively.
It is connected to the air pressure source 11 through the switching valves 8, 9, and 10, and when it is wide open, that is, when it is on standby, the first and second switching valves 8 and 9 are turned off, and the third switching valve 10 is turned on. The air from the pneumatic source 11 is supplied from the third switching valve 10 to the return port 7 of the outer cylinder 2, and the air is discharged from the piston pressurization port 5 and the inner cylinder pressurization port 6. The pressurizing piston 4 is moved back and forth. Next, when moving from the large open position to the small open position, that is, when moving through the preliminary stroke, the second switching valve 9 is turned ON from the large open position, and the air pressure source 11 is The air is supplied to the return port 7 via the third switching valve 10 and the air is supplied to the outer cylinder 2 via the second switching valve 9.
is supplied to the inner cylinder pressurizing port 6, and the pressurizing piston 4 is
The inner cylinder 3 is advanced with the inner cylinder 3 being retracted into the inner cylinder 3, and the pressurizing piston 4 is advanced to an intermediate position. Next, when moving from the small open position to the pressurizing position, that is, when moving through the pressurizing stroke, the first and second switching valves 8 and 9 are turned ON, as shown in Fig. 3.
Then, the third switching valve 10 is turned OFF and the air from the air pressure source 11 is passed through the first and second switching valves 8 and 9 to the piston pressurizing port 5 of the outer cylinder 2 and the inner cylinder pressurizing port 6. At the same time, air is discharged from the return port 7 to move the pressurizing piston 4 forward. Then, spot welding or the like is performed by combining the above operations.

By the way, when the above-mentioned two-stage stroke cylinder 1 shifts from wide open to pressurizing, in order to keep the pressurizing force constant, it is necessary to move the inner cylinder 3 forward first and then move the pressurizing piston 4 forward. In the conventional drive device, when moving from large opening to small opening, air is supplied from the inner cylinder pressurizing port 6 and return port 7 of the outer cylinder 2, and the inner cylinder 3
Due to the difference between the pressure-receiving area of the inner cylinder 3 and the pressure-receiving area of the pressurizing piston 4, the moving speed of the inner cylinder 3 is slow and the cycle time becomes long.

(b) Purpose of the invention This invention is designed to exhaust air from the return port of the outer cylinder only during the transition when the two-stage stroke cylinder is moved from the wide open state to the small open state, thereby reducing the amount of air that acts on the back side of the inner cylinder. However, the present invention aims to provide a driving device for a two-stage stroke cylinder that moves the inner cylinder quickly and, when the inner cylinder moves to the forward end, supplies air to the return port to hold the pressurizing piston in the backward position. It is something to do.

C. Structure of the device This device has an inner cylinder with an open front surface slidably housed in an outer cylinder, a pressurizing piston slidably housed in the inner cylinder, and an inner cylinder at the rear end of the outer cylinder. A piston pressurizing port that penetrates the cylinder and communicates with the back side of the pressurizing piston, an inner cylinder pressurizing port that communicates with the back side of the inner cylinder, and a return port that communicates with the front side of the pressurizing piston at the front end. 2, configured to move the inner cylinder back and forth within the outer cylinder and move the pressurizing piston back and forth within the inner cylinder.
A drive device for a stage stroke cylinder, including a 5-port, 2-position electromagnetic switching valve with two solenoids and a 5-port, 2-position electromagnetic switching valve with one solenoid.
The electromagnetic switching valve with two solenoids connects the pump port to the air source. The first cylinder port is connected to the air tank, the second cylinder port is connected to the inner cylinder pressurizing port of the two-stage stroke cylinder, the first return port is opened to the atmosphere, and the second cylinder port is connected to the air tank. connect the return port of the controller to the throttle valve,
The spring offset type electromagnetic switching valve has a pump port connected to the air pressure source, a first cylinder port connected to the pump port of the pilot type switching valve, and a second cylinder port connected to the two-stage stroke cylinder. The pilot type switching valve connects the cylinder port to the return port of the two-stage stroke cylinder and opens the return port to the atmosphere; A part of the exhaust air from the second return port of the electromagnetic switching valve having the two solenoids is made to act on the pilot type switching valve.

The drive device with the above configuration operates when the spring offset type solenoid switching valve is in the OFF state and the first
When the solenoid is turned ON, air from the pneumatic source is supplied from the return port of the two-stage stroke cylinder to the front chamber of the piston through the spring offset type solenoid switching valve, the pilot type switching valve, and the back of the pressurizing piston and inner cylinder. The side air is exhausted from the piston pressure port and the inner cylinder pressure port through the spring offset type electromagnetic switching valve and the electromagnetic switching valve, respectively, and the two-stage stroke cylinder is in a wide open state with both the inner cylinder and the pressure piston retracted. Become. At this time, part of the air from the pneumatic source is supplied to the air tank via the electromagnetic switching valve and stored therein.

Next, install the spring offset type solenoid switching valve.
Turn on the second solenoid of the solenoid switching valve when it is OFF.
Then, air from the pneumatic source is supplied to the back of the inner cylinder from the inner cylinder pressure port of the two-stage stroke cylinder via the electromagnetic switching valve, and at the same time, the air in the air tank is supplied to the pilot type switching valve to Switching, the air in the front chamber of the piston of the two-stage stroke cylinder is exhausted, the inner cylinder is moved forward, and a small opening state is achieved. When the inner cylinder moves to the forward end and the air in the air tank runs out, the pilot switching valve returns to its original position, and the air from the air pressure source passes through the spring offset electromagnetic switching valve and the pilot switching valve again to the piston from the return port. The two-stage stroke cylinder is sent to the front chamber,
The pressurizing piston is kept in a slightly open state in which it is retracted.

With the second solenoid of this solenoid switching valve turned on, turn on the spring offset type solenoid switching valve.
Then, air from the air source is supplied to the back of the piston from the piston pressurizing port of the two-stage stroke cylinder via the spring-set electromagnetic switching valve, and the air in the front chamber of the piston is supplied to the pilot-type switching valve and spring-off via the return port. The air is exhausted through a set type electromagnetic switching valve, and the pressurizing piston moves forward.

D. Embodiment FIG. 4 is a diagram showing an embodiment of the present invention. In the figure, the same components as those in FIG.

In Fig. 4, 15 is a 5-port, 2-position electromagnetic switching valve (hereinafter referred to as the first electromagnetic switching valve) for switching the two-stage stroke cylinder 1 between large opening and small opening. A first solenoid 16 and a second solenoid 17 are provided.
This first electromagnetic switching valve 15 is connected to the first solenoid 1
6 is turned on, the pump port P1 and the first cylinder port A1 are communicated, and the second cylinder port B1 and the first return port R1 are communicated, and conversely, the second solenoid 17 is turned on. When turned on, pump port P1 and second cylinder port B
1, and the first cylinder port A
1 and the second return port R1' are configured to communicate with each other.

18 is a 5-port, 2-position spring offset type electromagnetic switching valve (hereinafter referred to as the second electromagnetic switching valve) for pressurizing the two-stage stroke cylinder 1.
Then, the third solenoid 19 installed on the side
When turned ON, the pump port P2 and the second cylinder port B2 are communicated, and the first cylinder port A2 and the second return port R2' are communicated, and when the third solenoid 19 is turned OFF, the pump port P2 and the second cylinder port B2 are communicated. ,
The pump port P2 and the first cylinder port A2 are configured to communicate with each other, and the second cylinder port B2 and the first return port R2 are configured to communicate with each other.

20 is a 3-port, 2-position pilot type switching valve (hereinafter referred to as the pilot valve) for exhausting air from the return port 7 when the two-stage stroke cylinder 1 shifts from large opening to small opening. When the pilot pressure is applied, the cylinder port A3 and the return port R3 are communicated with each other, and when the pilot pressure is not applied, the pump port P3 and the cylinder port A3 are configured to be communicated with each other.

21 is an air tank that stores a predetermined amount of air. 22 is a throttle valve that throttles the flow rate of exhausted air, and 23 is a pneumatic pressure source.

The first electromagnetic switching valve 15 is connected to the pump port P1.
is connected to the pneumatic source 23, and the first cylinder port A
1 is connected to the air tank 21, the second cylinder port B1 is connected to the inner cylinder pressurizing port 6 of the two-stage stroke cylinder 1, the first return port R1 is opened to the atmosphere, and the second return port R1' is connected to the air tank 21. is connected to the throttle valve 22, and is further connected by piping so as to apply pilot pressure to the pilot valve 20 from the upstream side of the throttle valve 22. Further, the second electromagnetic switching valve 18 connects the pump port P2 to the air pressure source 23, connects the first cylinder port A2 to the pump port P3 of the pilot valve 20, and connects the first cylinder port A2 to the pump port P3 of the pilot valve 20.
Connect the cylinder port B2 of the cylinder port B2 to the piston pressurizing port 5 of the two-stage stroke cylinder 1, and
The return ports R2 and R2' are opened to the atmosphere. Furthermore, the pilot valve 20 has its cylinder port A3 connected to the return port 7 of the two-stage stroke cylinder 1.

In the above configuration, when the first solenoid 16 of the first electromagnetic switching valve 15 is turned ON while the third solenoid 19 of the second electromagnetic switching valve 18 is OFF, the air from the pneumatic source 23 is A predetermined amount of air is stored in the air tank 21 through the pump port P1 of the first electromagnetic switching valve 15 and the first cylinder port A1, and the air is stored in the air tank 21 through the pump port P1 of the first electromagnetic switching valve 15, the first cylinder port A2, and the pilot valve. The air on the back of the pressurizing piston 4 is supplied to the piston front chamber from the return port 7 of the two-stage stroke cylinder 1 through the pump port P3 and cylinder port A3 of The air is exhausted through the second cylinder port B2 and the first return port R2, and the air on the back side of the inner cylinder 3 is transferred from the inner cylinder pressurizing port 6 to the second cylinder port B1 and the first return port B1 of the first electromagnetic switching valve 15. The inner cylinder 3 and pressurizing piston 4 of the two-stage stroke cylinder 1 move back together, and the two-stage stroke cylinder 1 enters a wide open state.

Next, when the second solenoid 17 of the first electromagnetic switching valve 15 is turned ON while the third solenoid 19 of the second electromagnetic switching valve 18 is in the OFF state, the pneumatic pressure is Air from the source 23 is supplied to the back surface of the inner cylinder 3 from the inner cylinder pressurizing port 6 of the two-stage stroke cylinder 1 through the pump port P1 of the first electromagnetic switching valve 15 and the second cylinder port B1, and is then supplied to the back surface of the inner cylinder 3. 3 and the pressurizing piston 4 move forward to enter a small open state. During this transition, the air stored in the air tank 21 passes through the first cylinder port A1 and the second return port R1' of the first electromagnetic switching valve 15, and the flow rate is throttled by the throttle valve 22 and exhausted. During this time, the pilot pressure acts on the pilot valve 20 to switch it, so the air sent from the pump port P2 of the second electromagnetic switching valve 18 through the first cylinder port A2 is blocked by the pilot valve 20, and The air in front of the pressurizing piston 4 of the two-stage stroke cylinder 1 is exhausted from the return port 7 through the cylinder port A3 and return port R3 of the pilot valve 20, and the pressurizing piston 4 and the inner cylinder 3 are rapidly moved forward. When all the air in the air tank 21 is exhausted, the pilot pressure to the pilot valve 20 disappears, and as shown in FIG. The air that has come in is sent again to the front surface of the piston from the return port 7 of the two-stage stroke cylinder 1 via the pump port P3 and cylinder port A3 of the pilot valve 20. Note that the throttle valve 22 is set at a flow rate such that the air in the air tank 21 is discharged even in a slightly longer time than the time required for the inner cylinder 3 to move from the backward position to the forward position.

Next, with the second solenoid 17 of the first electromagnetic switching valve 15 turned on, the second electromagnetic switching valve 18
When the third solenoid 19 is turned ON, the air from the pneumatic source 23 passes through the pump port P1 of the first electromagnetic switching valve 15 and the second cylinder port B1 to the inner cylinder, as shown in FIG. It is supplied into the outer cylinder 2 from the pressurizing port 6, and is also supplied into the inner cylinder 3 from the piston pressurizing port 5 via the pump port P2 of the second electromagnetic switching valve 18 and the second cylinder port B2, and further pressurized. The air in front of the pressure piston 4 is supplied from the return port 7 to the pilot valve 20.
cylinder port A3, pump port P3, second
The first cylinder port A ₂ of the electromagnetic switching valve 18,
The air is exhausted through the second return port _R'2 , and the pressurizing piston 4 moves forward to become pressurized.

Next, from the pressurized state, the third solenoid switching valve 18
When the solenoid 19 is turned off, it returns to its original state, and as shown in FIG.
It is supplied to the inner cylinder pressurizing port 6 via the second cylinder port B1, and the second electromagnetic switching valve 1
8 pump port P2, first cylinder port A
2. Supplied to return port 7 via pump port P3 and cylinder port A3 of pilot valve 20,
The air on the back of the pressurizing piston 4 is exhausted from the piston pressurizing port 5 through the second cylinder port B2 of the second electromagnetic switching valve 18 and the first return port R2, and the pressurizing piston 4 enters the inner cylinder 3. enters and becomes slightly open.

Therefore, by controlling the first electromagnetic switching valve 15 and the second electromagnetic switching valve 18 in appropriate combinations, the two-stage stroke cylinder 1 is expanded and contracted from wide open to pressurized, and from pressurized to wide open, thereby performing spot welding. etc.

Effects of the invention According to the invention, by controlling the 5-port, 2-position electromagnetic switching valve and the 5-port, 2-position spring offset type electromagnetic switching valve, the two-stage stroke cylinder can be opened wide and pressurized. It can be expanded and contracted in two stages at will, making it easier to operate, and the air in front of the piston of the two-stage stroke cylinder can be automatically exhausted when transitioning from large opening to small opening. , the transition speed can be increased, and since the pressurizing piston is pushed in the backward direction again after the transition to the small opening, the piston does not move forward until the inner cylinder has completed its forward movement, and pressurizing can be performed accurately. This greatly improves work efficiency, and by using this to drive the movable electrode of a spot gun, it is possible to perform welding work in a short time.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional two-stage stroke cylinder drive device, FIGS. 2 and 3 are diagrams showing its operation, and FIG. 4 is a diagram showing a two-stage stroke cylinder drive device according to the present invention, Figures 5 to 7
The figure is a drawing showing the operation. 1...Two-stage stroke cylinder, 2...Outer cylinder, 3...Inner cylinder, 4...Pressure piston,
5...Piston pressure port, 6...Inner cylinder pressure port, 7...Return port, 15...5 port/2 position electromagnetic switching valve, 18...5 port/2
Position spring offset type solenoid switching valve, 20
... Pilot type switching valve, 21 ... Air tank, 22 ... Throttle valve, 23 ... Air pressure source.

Claims (1)

[Scope of utility model registration request] An inner cylinder with an open front surface is slidably housed in an outer cylinder, a pressurizing piston is slidably housed in the inner cylinder, and the rear end of the outer cylinder is pressurized by passing through the inner cylinder. A piston pressurizing port that communicates with the back side of the piston and an inner cylinder pressurizing port that communicates with the back side of the inner cylinder are formed, and a return port that communicates with the front side of the pressurizing piston is formed at the front end. A 5-port, 2-position electromagnetic switching valve with two solenoids, which is a drive device for a two-stage stroke cylinder configured to move an inner cylinder back and forth and move a pressurizing piston back and forth within the inner cylinder. and 1
A 5-port, 2-position spring offset type electromagnetic switching valve with two solenoids, a 3-port, 2-position pilot type switching valve, an air tank, a throttle valve, an air pressure source, etc., and an electromagnetic switching valve with the above two solenoids. The valve connects the pump port to the air source, the first cylinder port to the air tank, the second cylinder port to the inner cylinder pressurization port of the two-stroke cylinder, and the first cylinder port to the air tank.
The return port of the valve is opened to the atmosphere, and the second return port is connected to the throttle valve, and the spring offset electromagnetic switching valve is connected to the pump port to the air pressure source and the first cylinder port to the pilot valve. The pilot type switching valve is connected to the pump port of the pilot type switching valve, the second cylinder port is connected to the piston pressurizing port of the two-stage stroke cylinder, and the first and second return ports are opened to the atmosphere. , connect the cylinder port to the return port of the two-stage stroke cylinder, open the return port to the atmosphere, and direct a portion of the exhaust from the second return port of the electromagnetic switching valve having the two solenoids to the pilot type switching valve. A driving device for a two-stage stroke cylinder, characterized in that the driving device operates a two-stage stroke cylinder.