JPS5848764B2 - Pneumatically operated cylinder - Google Patents

Description

Detailed Description of the Invention (a) Object of the Invention (Technical Field of the Invention) The present invention relates to a pneumatic drive booster that performs rapid forwarding, pressure increasing feeding, and rapid return operations of an output piston by, for example, supplying and discharging compressed air. The present invention relates to pneumatically operated liquid cylinders such as pressure cylinders and hydro check cylinders, and in particular to their liquid supply and drainage devices.

(Prior art and its problems) FIG. 5 is a sectional view showing a conventional pneumatically operated cylinder as described in, for example, Japanese Patent Laid-Open No. 48-13782.

As shown in this figure, the ring piston 9 in the ring cylinder 8
is advanced to the left end position and the oil piston 3 and pressure booster piston 5 are moving toward the head side, and when compressed air is supplied from the port P3, the oil in the ring cylinder 8 passes through the oil path 10 and enters the through hole 7. The oil piston 3 is press-fitted into the head-side chamber of the oil cylinder 1, and the oil piston 3 moves forward to the left to perform rapid forwarding.

Next, port P3 is closed, and port P of pressure increase cylinder 4 is closed.
When compressed air is supplied from the through hole I, the pressure in the through hole I is increased by the ram 6 to a high pressure, and the oil piston 3 moves forward to the left under high pressure to perform work for the load.

When the port P1 of the pressure increase cylinder 4 and the port P3 of the ring cylinder 8 are exhausted, and compressed air is supplied from the ports P2 and P4, the pistons 3 and 5.9 return to their original positions shown in the figure.

However, in such a conventional sealed pneumatically operated liquid cylinder, the lower blind plug 24 is removed to drain oil, and the upper blind plug 25 is removed to inject oil.
It is inconvenient to replenish oil or change oil.

That is, the oil can be discharged by moving the pistons 3 and 9 to the right side using pneumatic pressure to push out the oil, but it is difficult to inject the oil.

That is, because of the sliding resistance of the ring piston 9, it is impossible to supply oil while moving the ring piston 9 forward to the left.

Therefore, the ring piston 9 must be oiled while being pressurized to the extent that it can be moved against sliding resistance, which makes the work more complicated.

In addition, the air bubbles that have entered the hydraulic circuit system must be removed each time by removing the blind plug, which is not only troublesome but also impossible to remove air bubbles smoothly and reliably.

(Technical Problem of the Invention) A technical problem of the present invention is to provide an operation for supplying and discharging liquid into a liquid cylinder in order to drive a piston of the liquid cylinder.
To solve this problem with pneumatically operated cylinders that operate by moving a pneumatic piston back and forth, making oil replenishment and replacement easy, and air bubbles automatically discharged. There is a particular thing.

(b) Configuration of the invention (technical means of the present invention) In order to solve this technical problem, the technical means of the present invention is to supply and discharge liquid into the liquid cylinder in order to drive the piston of the liquid cylinder. In a pneumatically operated cylinder whose operation is performed by the back and forth movement of a piston operated by air pressure, the pressure tank is filled with liquid to the extent that an air chamber remains at the top, and the liquid level is made completely or partially transparent so that the liquid level can be seen visually. The liquid port of the liquid chamber of this pressure tank is connected to the liquid chamber of the liquid cylinder via a flow control valve connected in parallel with the check valve, and compressed air pressure is applied to the air chamber from the air port or atmospheric pressure is applied to the air chamber. In addition to connecting a valve device so that it can be opened to When the lower float, which has a specified upper limit position, descends, it contacts the valve seat at the bottom of the liquid chamber and closes the liquid port, and when the upper float rises, it contacts the valve seat of the air port in the air chamber and closes it. The configuration is as follows.

(Effect of technical means) According to this technical means, when liquid is supplied from the pneumatically operated cylinder to the liquid cylinder to drive the liquid cylinder, the liquid in the pressure tank is also supplied to the liquid cylinder side. As the center decreases, the liquid in the liquid cylinder returns to the pneumatic operation cylinder and then returns to the pressure tank, increasing the amount of liquid in the pressure tank.

When the liquid level in the pressure tank rises in this way, the air pressure is released to the atmosphere, so if there are air bubbles in the liquid in the liquid cylinder or pneumatically operated cylinder, the air bubbles will be removed. Exhausted into the air chamber.

In addition, with a valve device connected to the air chamber of the pressure tank, the air chamber can be connected to a compressed air source to pressurize the liquid level, and the liquid in the pressure tank can be pressurized into the liquid cylinder via the flow control valve. .

Therefore, by injecting liquid into the pressure tank with the air chamber open to the atmosphere, closing the cap, and applying compressed air pressure to the air chamber, the previously injected liquid is forced into the liquid cylinder.

By repeating this operation, the liquid necessary for driving the liquid cylinder is filled.

In addition, if the piston rod of the liquid cylinder protrudes even if liquid is supplied from the pressure tank while the liquid cylinder is driven in the return direction by pneumatic pressure, it means that the liquid filling chamber of the liquid cylinder and pneumatically operated cylinder is full. Become.

When the piston of the liquid cylinder is returned to the head side in this state, the liquid in the liquid cylinder is pushed back into the pressure tank, and the amount of liquid can be confirmed by the liquid level in the pressure tank at this time.

Pressure tanks are completely or partially transparent so that they can be seen from the outside, so just by looking at them from the outside, you can
Coupled with the fact that the excess liquid filled in the liquid cylinder and the pneumatically operated cylinder is returned to the pressure tank as described above, the amount of liquid can be easily confirmed.

Of the two floats built into the pressure tank, the upper float is always floating on the liquid level, so if you forget to adjust the flow rate control valve and a sudden increase in liquid returns to the pressure tank, The upper float contacts the valve seat of the air port and closes it, preventing liquid from being discharged from the pressure tank.

Also, if you forget to replenish the liquid and the amount of liquid is low, air will be easily sucked in, but if the liquid is low, the lower float will descend and contact the valve seat at the bottom of the liquid chamber, closing the liquid port. .

Therefore, air is not sucked from the liquid port side to the liquid cylinder side.

Only by providing upper and lower floats and taking all possible precautions will it be possible to easily exchange liquids and remove air bubbles using a pressure-resistant tank such as the one described above.

Since oil-resistant rubber valve bodies are provided on the upper and lower floats at positions facing the valve seats, the ports are reliably closed by the upper and lower floats.

Further, at the end of the return of the piston of the liquid cylinder, a cushioning effect is provided by the throttling effect of the flow control valve.

This flow rate control valve also prevents foaming when the liquid returns from the liquid cylinder side to the pressure tank.

By providing a check valve in parallel with the flow control valve, when supplying liquid to large volume liquid cylinders and pneumatically operated cylinders, the liquid can pass through both the flow control valve and the check valve. As a result, liquid is quickly supplied.

Conversely, when liquid flows from the liquid cylinder side to the pressure tank side, the flow rate control valve acts as a resistance, so when the cylinder returns, the piston of the pneumatically operated cylinder returns completely to its original position, and then the cushioning action occurs. The liquid cylinder returns to the rear end.

(c) Effects of the Invention As described above, according to the present invention, air bubbles are automatically discharged when the liquid in the liquid cylinder is pushed back into the pressure tank by the movement of the piston during operation, so it is possible to There is no need for troublesome air bleeding operations.

Furthermore, by applying compressed air pressure to the air chamber of the pressure tank or opening it to the atmosphere, liquid can be easily replenished or oil (liquid) replaced.

In particular, two floats (upper and lower) are floated in a pressure-resistant tank, and when the lower float descends, the liquid port at the bottom of the liquid chamber is closed, and when the upper float rises, the air port at the ceiling of the air chamber is closed. There is no fear that air will be sucked into the liquid cylinder or that liquid will flow out of the pressure tank.

By making the pressure tank completely or partially transparent,
Not only can you check the amount of liquid at a glance from the outside, but you can also indirectly check the position of the piston inside the liquid cylinder or pneumatically operated cylinder, which is convenient when replacing the liquid.

(d) Practical Example of the Invention Next, how the pneumatically operated liquid cylinder according to the present invention is actually implemented will be explained by a practical example.

FIG. 1 is a sectional view of a pneumatically operated liquid cylinder implementing the technical means of the present invention, and FIG. 2 is a sectional view showing its quick return process.

An oil piston 3 having an output piston rod 2 is built into the oil cylinder 1, and a port P4 on the rond side is connected to an air valve (not shown).

A booster air cylinder 4 is installed on the head side of the oil cylinder 1.
A ram 6 fixed to the piston 5 is inserted into the head side through hole 7, and ports P1 and P2 for supplying and discharging compressed air are opened at the front and rear of the pressure increasing cylinder 4.

A ring cylinder 8 is provided concentrically outside the oil cylinder 1, and a ring piston 9 is housed therein.

The oil cylinder head side chamber of the ring cylinder 8 is an oil chamber, and this oil chamber communicates with the through hole 7 via an oil passage 10.

The oil cylinder rond side chamber of the ring cylinder 8 is an air chamber, and an air port P3 is opened therein.

The air port P3 of the ring cylinder and the air port P4 of the oil cylinder are respectively piped to individual ports of the three-way switching valve 11, and a transparent pressure-resistant tank 13 and a check valve are connected between the common boat of the three-way switching valve and the oil pipe 10. A flow control valve 12 with a valve is connected in series through piping.

The flow control valve 12 includes a check valve 12'' in parallel with the throttle valve 12'.
This is a well-known device with a built-in function.

The pressure tank 13 is made up of a transparent pipe 15 with excellent pressure resistance, with covers 16 and 16' attached to the top and bottom of the pipe, which are tightened with tie rods.The cap 17 of the top cover 16 is removed and oil is filled to the extent that an air chamber 18 remains at the top. After filling, the cap 17 is closed.

The upper cover 16 has an air port 14 opening in the ceiling of the air chamber 18, a valve seat 14' formed at the inner end thereof, and an outer end connected to the common port of the switching valve 11.

A liquid port 20 opening at the bottom of the liquid chamber 19 is formed in the lower cover 16', a valve seat 20' is formed at the inner end thereof, and the outer end is connected to the flow rate control valve 12.

An upper float 21 and a lower float 22 are built into the pressure tank.

The upper float 21 is floating on the liquid level, and when it rises with the liquid level, the oil-resistant rubber valve element 21' at the upper end comes into contact with the valve seat 14', closing the air port 14.

A stopper mechanism 23 such as a snap ring is provided in the middle of the transparent pipe, and a lower float 22 is built in below the stopper 23, so that even if the liquid level rises, the lower float 22 will hit the stopper 23 and no more It is designed to prevent it from rising.

Then, as the liquid level falls, or the liquid port 20
When the lower float 22 descends due to negative pressure on the side, the oil-resistant rubber valve body 22' at the lower end comes into contact with the valve seat 20', closing the liquid port 20.

Next, the operation of this device will be explained.

When compressed air is supplied from the air ports P2 and P4 and the other air ports are used for exhaust, the pressure boosting air piston 5 and the oil piston 3 are moved back as shown in FIG. 1, and normally they are stopped at this retreated position.

To advance the oil piston 3, exhaust port P4 and supply air from port P3 to retract the ring piston 9 and lower the oil level in the pressure tank 13.
The oil in the ring cylinder 8 and the oil in the pressure tank 13 flow into the oil cylinder 1 through the oil passage 10 and the through hole 7, and at this time the oil piston 1 is moved forward in rapid traverse.

Next, when port P3 is closed to stop the ring piston 9 and air is supplied from port P1 to advance the ram 6, the piston 5
With the hydraulic pressure increased in proportion to the area difference between the oil piston 3 and the ram 6, the oil piston 3 is slowly fed under increased pressure.

Using the pressure at this time, the piston rod 2 is caused to perform various types of processing.

After completing the work, if air is supplied to ports P2 and P4 and the others are exhausted, the pressure booster piston 5 and oil piston 3 will move back,
The oil piston 3 returns quickly.

At this time, the oil in the oil cylinder flows into the pressure tank 13 and the ring cylinder 8 through the through hole 7 and the oil passage 10, and moves the ring piston 9 forward as shown in FIG.

According to the present invention, in a pressure tank, it is possible to prevent air from being sucked into the cylinder or from overflowing from the air port due to an abnormal rise in the oil level.

That is, when air is supplied from port P3 to move oil piston 3 forward, air pressure passes through three-way valve 11 and enters pressure tank 1.
Since the oil in the liquid chamber 19 also flows out from the liquid port 20, the oil level falls.

At this time, if the forward speed of the piston slows down due to setup operations, for example, and the amount of downward movement of the oil level is large and the oil level drops to near the lower liquid port, there is a risk of air being suddenly sucked into the cylinder. be.

According to the present invention, the lower float 22 descends as the oil level falls, and the liquid port 20 side becomes a negative pressure state with respect to the air chamber 18, and the lower float suctions and descends as shown by the chain line in FIG. As a result, the valve body 22' comes into contact with the valve seat 20', so air is not suddenly sucked into the cylinder from the pressure tank.

If you forget to replenish the oil and the oil level is low, it is easy for air to be sucked in, but even if the oil level is low, the automatic valve closing action by the lower float will reliably prevent air sucking.

On the other hand, when the oil piston 3 retreats, port P4
Since P3 is the air supply and P3 is the exhaust, the oil in the oil cylinder flows into the ring cylinder 8 and the pressure tank 13, but the flow of oil into the pressure tank 13 is suppressed by the throttle valve 12' in the flow control valve 12. Therefore, the ring piston 9
The oil level cannot rise much until it reaches the front end, and it is at a position where it has fallen by h in Figure 2.

When the ring piston 9 moves to the front end as shown by the solid line in FIG. When it reaches the end and stops, the oil will stop rising.

That is, the oil level in the pressure tank when the oil piston 3 and piston 5 move back and stop represents the oil amount, and the oil amount can be determined at a glance by simply looking at the oil level in the tank 13.

At the same time, you can also see how dirty the oil is.

When the oil piston 3 returns, a large load is applied due to galling, etc., and the return speed of the piston suddenly becomes slow.
The oil on the 0 side easily passes through the throttle valve 12' and rises, the oil level rises abnormally, and the oil tries to flow out from the air port 14, but at this time, as the oil level rises, the upper float 21 rises as shown by the chain line. Since the air port 14 is also raised and the valve body 21' closes the air port 14, there is no fear of oil being discharged.

After the ring piston 9 reaches the front end, the outflow of oil in the oil cylinder is suppressed by the action of the throttle valve 12', which is advantageous because the oil piston has a cushioning effect at its return end.

Furthermore, since the amount of oil returning from the oil pipe 10 is throttled by the throttle valve 12', there is no ripple when the oil returns to the pressure tank 13.

Even if you forget to adjust the throttle valve 12' and operate it with the throttle valve open, that is, without any cushioning effect, the amount of oil returned to the pressure tank 13 increases and tends to overflow. Since the air port 14 is closed by the upper float, there is no risk of this happening.

The stroke H between the lower float valve element 22' and the valve seat 20', the upper limit of which is regulated by a stopper in the pressure tank, also determines the cushion stroke at the retreating end of the piston rond and remains constant.

That is, when the liquid in the pressure tank is supplied to the liquid cylinder and the liquid level falls, the lower float also falls together with the liquid, closing the valve seat 20'.

Therefore, the stroke of the lower float is constant, and the amount of oil supplied from the pressure tank to the liquid cylinder is constant.

This means that after the ring piston 9 returns to the left end, the amount of oil pushed back into the pressure tank by the piston 3 is always constant, and as a result, the stroke at which the piston 3 performs its cushioning action remains constant.

As explained in Figure 5, conventional pressure booster cylinders are completely sealed, so in order to discharge air bubbles, it is necessary to remove the blind stopper each time to let them escape, and the air bubbles do not drain smoothly. Although there is a problem, in the device of the present invention, when the oil in the oil cylinder returns to the pressure tank, it returns to the tank together with air bubbles.

Air bubbles that return to the tank rise into the air chamber and are discharged through the air port.

Therefore, the oil cylinder is operated to advance the piston.
While reversing, the air in the oil is automatically discharged.

If you want to remove all the air bubbles at once, press the 3-way valve 11 in the stopped state shown in Figure 1 to remove all the air bubbles from the port P4.
By applying air pressure to the pressure tank 13 through the pressure tank 13, the oil is forcibly increased in the right chamber of the oil cylinder, and then the 3-way valve is released to restore the oil cylinder. When the pressurized oil returns to the pressure tank, air bubbles is also discharged at the same time.

If a large amount of air bubbles are mixed in, repeat this operation several times.

When the oil in the cylinder is exhausted and needs to be refilled, it is sufficient to simply remove the cap 17 of the pressure tank and replenish the oil.

In the stationary state shown in FIG. 1, the port P3 of the ring cylinder is in the exhaust state, and the air chamber 18 of the pressure tank is open to the atmosphere, so that refueling is possible simply by removing the cap 17.

If the oil is dirty and you want to replace it all, exhaust only the port P1 and supply air to all the others, remove the blind plug 24 at the lower end, and drain all the oil.

In this way, with all the pistons retracted, close the blank plug 24, supply air to ports P2 and P4, and exhaust the others, and then
After removing the cap 17 and filling the tank with oil, close the cap.

Next, the oil in the tank is forced into the ring cylinder 8 by pressing the operation button of the three-way valve to apply air pressure to the air chamber of the tank from ports 1-P4.

Once press-fitting is complete, release the three-way valve operation button, remove the tank cap again, refill the oil, and press-fit it.

When this operation is repeated, the ring piston 9 gradually moves forward with the oil press-fitted into the ring cylinder 8, and when the ring cylinder is filled with oil, the ring piston reaches the front end and stops.

Furthermore, as the oil is continued to be press-fitted, the oil flows into the oil cylinder and the piston rod 2 begins to move forward, so it is confirmed that the ring cylinder is filled with oil and the oiling operation is completed.

When the operation button 11 of the three-way valve is released, the air chamber 18 becomes atmospheric pressure, and the oil in the oil cylinder is pushed back into the pressure tank, resulting in the stationary state shown in Figure 1. Although a transparent pipe is shown as an example for ease of use, it is also possible to partially display the oil level by providing a separate transparent gauge pipe or the like.

The present invention is effectively applied to any closed type liquid cylinder operated by pneumatic pressure other than the pressure increasing cylinder shown in FIGS. 1 and 2.

Figure 3 is an example of actual winding on a hydro check cylinder.
The figure shows an example of a position cylinder, and in these cases, the switching valve that applies compressed air pressure to the oil level of the pressure tank or releases it to the atmosphere is indirectly connected.

Note that when the switching valve 26 in FIG. 3 is in the state shown, the liquid passes through both the throttle valve and this switching valve and is supplied to the left liquid cylinder, so that rapid forwarding is performed.

When the switching valve 26 is pushed to the closed state, liquid is supplied from the right liquid cylinder to the left liquid cylinder only by the throttle valve, and low-speed feeding is performed.

When the switching valve 27 shown in FIG. 4 is pushed to a communicating state, liquid is supplied from the ring cylinder to the liquid cylinder and rapid feed is performed.

During this operation, if the switching valve 27 is set to the state shown in the figure,
The liquid supply from the ring cylinder to the liquid cylinder is interrupted and the liquid cylinder is stopped.

Note that it is of course possible to use liquids other than oil as the filling liquid.

[Brief explanation of drawings]

Fig. 1 is a central vertical cross-sectional view of a pneumatically operated liquid cylinder in a stopped state in which the present invention is implemented, Fig. 2 is a central vertical cross-sectional view in the fast return process, and Fig. 3 is a central vertical cross-sectional view of a pneumatically operated liquid cylinder in which the present invention is implemented in a hydro check cylinder. FIG. 4 is an example of a leprosy case, in which it is actually wrapped around a position cylinder. FIG. 5 is a longitudinal sectional view illustrating a conventional pneumatically operated liquid cylinder. In the drawing, 1 is an oil cylinder, 3 is an oil piston, 4 is a pressure boosting air cylinder, 6 is a ram, 7 is a through hole, 8
is a ring cylinder, 9 is a ring piston, 10 is an oil pipe,
11 is a three-way switching valve, 12 is a flow control valve, 13 is a pressure tank, 14 is an air port, 15 is a transparent pipe, 18 is an air chamber, 19 is a liquid chamber, 20 is a liquid port, 21 is an upper float, 22 is a lower 23 represents a float and a stopper, respectively.

Claims (1)

[Scope of Claims] 1. In a pneumatically operated cylinder in which the operation of supplying and discharging liquid into the liquid cylinder to drive the piston of the liquid cylinder is performed by the back and forth movement of a piston operated by air pressure, an upper part of the pressure tank is provided. Fill the tank with liquid to the extent that an air chamber remains, and make all or part of the tank transparent so that the liquid level can be seen visually. The air chamber is connected to the liquid chamber of the liquid cylinder through the air port, and a valve device is connected to the air chamber so that compressed air pressure can be applied from the air port or it can be released to the atmosphere. Two floats, upper and lower, are built into the pressure tank. A stopper means is provided between the upper float and the lower float, and when the lower float whose upper limit position during rising is regulated by this stopper means, it comes into contact with the valve seat at the bottom of the liquid chamber. A pneumatically operated cylinder characterized in that when a liquid port is closed and an upper float rises, it comes into contact with a valve seat of an air port in an air chamber and is closed. 2. The lower float is equipped with an oil-resistant rubber valve body at a position facing the liquid port at the bottom of the liquid chamber, and the upper float is equipped with an oil-resistant rubber valve body at a position facing the air port. A pneumatically operated cylinder according to claim 1.