JPS62110001A - Cushion device for fluid pressure cylinder - Google Patents

Abstract

PURPOSE:To efficiently fulfill a cushioning function by connecting a check relief valve and a throttle valve to a cylinder chamber on the capacity reducing side accompanying the advance of a piston, in the captioned device for a high speed emergency shut off valve used in an ultra-high vacuum system such as a plasma laboratory device. CONSTITUTION:A check relief valve 54 and a throttle valve 55 are connected to the cylinder chamber 18a on the rod side of a fluid pressure cylinder 1. These valves are opened when the fluid pressure in the cylinder chamber 18a becomes above a set value, with this fluid pressure as a pilot pressure. Thereby, when a piston 13 is advanced at a high speed, the pressure in the rod side cylinder chamber 18a rises, opening the check relief valve 54 to discharge a fluid in the rod side cylinder chamber 18a, via the throttle valve 55, and, thereby, the piston 13 can be smoothly stopped at the stroke end.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a cushion device for a fluid pressure cylinder used for shutting off a high-speed emergency shut-off valve, etc. This is to effectively reduce the impact at the end of the stroke, and to eliminate the bouncing phenomenon at the end of the stroke.

(b) Background of the technology Ultra-high vacuum systems such as accelerators and plasma experimental equipment that accelerate electrons or protons to near the speed of light are equipped with numerous measurement stations for various research purposes. A high-speed emergency shutoff valve is installed in the branch vacuum system that communicates the ultra-high vacuum system with each measurement station. When air enters the measuring station due to an operational error or other unexpected accident, the measuring station controller detects this quickly and activates a high-speed emergency shutoff valve to shut off the branch vacuum system. This is to prevent air intrusion accidents from spreading to the ultra-high vacuum system.

Conventionally, such technology has been disclosed, for example, in Japanese Patent Application Laid-Open No. 59-2
This method is known from Japanese Patent No. 26774 and the like.

On the other hand, this type of emergency shutoff valve, especially the emergency shutoff valve used in small accelerators for experiments in laboratories, etc., has a long period of time from when a sensor detects the intrusion of atmospheric air until the shutoff valve completes full opening operation. It is required that the time is 10 m5ec or less. Also, the hand tile that causes the emergency shutoff valve □1 to shut off at high speed is 1. It is desirable to use a pneumatic cylinder with a shock-reducing function from the viewpoints of ease of handling, economy, and the fact that air pressure can be easily obtained using an exhaust system for ultra-high vacuum.

(c) Conventional technology Conventionally, pneumatic cylinders with shock mitigation function were
One disclosed in Japanese Patent Application Laid-Open No. 52-6884 is known.

The cushion device for the pneumatic cylinder described above includes an exhaust relief valve that opens when the pressure of the air trapped between the piston and the end cover rises to a set value, and an exhaust relief valve that opens when the pressure of the air trapped between the piston and the end cover rises to the set value, and exhausts the air whose pressure has risen to the set value just before the end of the piston end stroke. It is equipped with a short-circuit exhaust passage that escapes to the port.

According to this cushion device, when the piston reaches the cushion stroke region, the air pressure between the piston and the end cover increases rapidly, and this pressure is maintained until just before the end of the stroke, and the relief valve is opened near the end of the stroke to rapidly increase the pressure. This makes it possible to exert an effective suspension action with a short stroke without causing a bounce phenomenon at the end of the stroke.

Problems to be Solved by the Invention In the conventional cushioning device as described above, the piston stroke is reduced to a fraction of the piston stroke by using a relief valve and a short-circuit passage.
Since the shock is alleviated with only a short stroke, there is a limit to the amount of absorbed kinetic energy required to exert an effective notion effect, at most 100 kinetic energy.
It can only be applied to cylinders that have an operating speed of about 0 to 2000 mm/sec. Furthermore, if the operating speed exceeds the above, the exhaust resistance will increase, and the peak pressure at the end of the stroke will become extremely high, resulting in a bounce phenomenon. It will not be possible to lower it all the way down.

That is, in the conventional cushion device as described above, 600
In addition to being unsuitable for shock mitigation of cylinders that operate at high speeds of the order of 0 mm/see, they also cannot be used as cylinder devices for high-speed emergency shutoff valves in ultra-high vacuum systems as described above.

In addition, in the conventional cushion device mentioned above, a method in which the entire stroke of the cylinder is a cushion stroke may be considered, but this would require twice the stroke of the cylinder and at the same time double the total length of the cylinder. There was a problem that shock mitigation without the bounce phenomenon could not be achieved.

The present invention was made to solve the above-mentioned conventional problems, and is capable of reliably absorbing shock at the end of the stroke even in high-speed operation of about 6000 mm/sec, and achieving a cushioning effect without bounce phenomenon. An object of the present invention is to provide a cushioning device for a fluid pressure cylinder.

(E) Means for Solving the Problems The cushioning device for a fluid pressure cylinder according to the present invention provides a low pressure fluid source for maintaining the cylinder chamber in a pre-pressure state in a cylinder chamber whose volume decreases as the piston of the fluid pressure cylinder moves forward. At the same time, the exhaust passage of the cylinder chamber on the volume reduction side is closed by the fluid pressure of the low pressure fluid source, and as the piston moves forward at high speed, the fluid pressure in the cylinder chamber on the volume reduction side exceeds a set value. Then, a check relief valve for generating the amount of kinetic absorption energy that opens this as a pilot pressure, and a restricting means for restricting the amount of fluid pressure discharged from the check relief valve on the side where the volume decreases through the check relief valve are provided. It is something.

(f) Effect In the present invention, when the piston is advanced at high speed, the prepressure fluid in the cylinder chamber on the volume decreasing side rises to exceed the fluid pressure for the advancement of the piston, thereby providing a brake against the forward kinetic energy of the piston. At the same time, the check relief valve opens and the compressed high-pressure fluid in the cylinder chamber on the volume decreasing side is discharged through the throttling means, thereby reducing the stroke of the piston. Enables smooth stopping at the end.

()) Embodiment of the Invention An embodiment of the invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 shows a principle configuration diagram of a high-speed cylinder device equipped with a cushion device according to the present invention, which can be roughly divided into a cylinder body 1 that performs stroke motion using fluid pressure such as air, and a pressure accumulation chamber that constantly stores fluid at a predetermined pressure. 2, a highly responsive electromagnetic three-way switching valve 3 that opens and closes the pressure accumulation chamber 2 and the head control space of the cylinder body 1, and an electromagnetic auxiliary control valve for controlling the forward movement of the piston, holding the forward end, and returning the same. 4, and a cushion pressure control mechanism 5 that communicates with the head side cylinder chamber of the cylinder body 1 and is for cushioning the impact at the end of the stroke and eliminating the bouncing phenomenon. − has been done.

As shown in FIG. 2, the cylinder body 1 includes a cylinder tube 11 with an open end, a rod cover 12 that closes the opening of the cylinder tube 11, and a rod cover 12 that slides inside the cylinder tube 11 along its longitudinal direction. It is composed of a movably fitted piston 13 and a piston rod 14 which is integrally connected to the piston 13 and projects outwardly through the rod cover 12, and which projects inside the rod cover 12. A rubber damper 1 is provided on the end surface of the provided boss portion 12a to reduce collision with the piston 13.
5 is fixed to the cylinder tube 11 facing the outer periphery of the boss portion 12a, and a communication port 1 is provided in the cylinder tube 11 facing the outer periphery of the boss portion 12a to communicate the cylinder chamber 18a on the rond side with the cushion pressure control mechanism 5.
6 is formed. Reference numeral 19 denotes a space formed in the cylinder chamber 18a when the piston 13 reaches the bending end where it collides with the rubber damper 15, and this space 19 compensates for machining errors due to a reduction in the volume of the cylinder chamber 18a as the piston 13 moves forward. This is to provide a stable cushioning effect.

The three-way switching valve 3 is attached to the end face of the head-side cylinder tube of the cylinder body 1, as shown in FIGS. A valve seat 31 that airtightly fits into the provided opening 17, and a plurality of valve ports 31 formed on this valve seat 31.
A movable disk 32 that opens and closes a and the movable disk 32
It is equipped with a spring member 33 that constantly presses the valve against the valve seat 31 to bias the valve port 31a to the closed state, and also has a solenoid 34 that attracts the movable disk 32 in the opening direction. A fixed iron core 3 having a high-pressure fluid inflow passage 35a that communicates the valve seat 31 and the pressure accumulation chamber 2 on the central axis.
A cylindrical cover 37 is hermetically fitted to the outer periphery of the fixed core 35, including the outer circumferential surface of the excitation coil 36. The solenoid 34 is fixed to the cylinder body l by screwing the solenoid 34 to the bottom outer end of the cylinder tube 11. Also, solenoid 34
The outer periphery of the cylinder tube 11 is sealed by a cover 38 fixed to the bottom outer end surface of the cylinder tube 11, and the container 21 is fixed to the cover 38 so as to form a space of a predetermined volume around the outer periphery. Form chamber 2. The container 21 forming the pressure accumulation chamber 2 is formed with an inflow port 22 that communicates with an external fluid pressure source 6 such as air pressure.
f/c+d) fluid is constantly accumulated.

The auxiliary control valve 4 is fixed to a valve block 51 of a cushion pressure control mechanism 5, which will be described later, as shown in FIGS. 2 and 3, and has a fluid inflow port 41, an outflow port 42, and a discharge port 43. Valve casing body 44 and this valve casing body 4
The spool 45 is slidably fitted into the spool 4 and switches between the outflow port 42, the inflow port 41, and the discharge port 43, a solenoid 46 for operating the spool 45, and a return spring 47. The inflow port 41 is connected to a passage 52 formed in the valve block 51.
The outflow port 42 is connected to a passage 53 formed in the valve block 51.
It communicates with the rod-side cylinder chamber 18b of the cylinder body 1 through a passage 11b formed in the cylinder tube 11.

The cushion pressure control mechanism 5 also includes a valve block 51 fixed to the outer periphery of the cylinder body 1, as shown in FIG.
The valve block 51 is equipped with a check relief valve 54 which communicates the rod side cylinder chamber 18a with the atmosphere when the pressure inside the rod side cylinder chamber 18a of the cylinder body 10 exceeds a set pressure.

The check relief valve 54 is connected to the rod side cylinder chamber 18a.
A cylindrical valve seat member 54 provided in a passage 54a between and the passage 16.
b, and a movable disk 54d that is slidably fitted into the passage 54a and opens and closes the opening of the discharge passage 54c formed in the valve seat member 54b and the low pressure fluid supply port 56.
Furthermore, a variable throttle valve 55 is provided on the atmosphere open side of the discharge passage 54c, and which variable throttle valve 5
5 is composed of a needle valve body 55a and its lock nut 55b. Further, the port 56 has low pressure (1,
5 kg f/cm) is connected to a fluid pressure source 8. The passage 54a into which low-pressure fluid flows is communicated with the rod-side cylinder chamber 18a through a check valve 57, as shown in FIG.

It is applied to the movable disk 54d in a direction to open the exhaust passage 54C. Therefore, when the piston 13 of the cylinder body 1 is retracted or at the retracted end, the low fluid pressure from the fluid pressure source 8 acts on the movable disc 54d to press the movable disc 54d into engagement with the opening of the valve seat member 54b. Then, the atmosphere side is closed, and the inside of the rod-side cylinder chamber 18a is maintained at a pressure (1.5 kg f/cffl) corresponding to the supply pressure of the fluid pressure source 8. Further, the pressure in the loft side cylinder chamber 18a generated as the piston 13 moves forward is applied to the valve seat member engagement side of the movable disk 54d as a pilot pressure through the pilot passage i58, and the compressed fluid in the loft side cylinder chamber Ba is When the pressure reaches a predetermined level and the pressure relative to the pressure receiving area on the valve seat member engaging side of the movable disc 54d becomes greater than the product of the pressure receiving area on the low pressure supply side of the movable disc 54d and the fluid pressure, the movable disc 54d is set to low pressure. By sliding it toward the fluid supply port 56 side, the inside of the cylinder chamber 8a on the rond side is communicated with the atmosphere through the variable throttle valve 55.

Next, the operation of this embodiment configured as described above will be explained.

FIG. 2 shows a state in which the piston 13 has returned to the head side (right side in the figure). At this time, low pressure (1.5ksr
The fluid pressure from the fluid pressure source 8 (f/cal') acts on the movable disk 54d of the check relief valve 54 to close the exhaust opening of the valve seat member 54b, and also closes the exhaust opening of the valve seat member 54b.
a. It is added to the cylinder chamber 8a on the rond side through the check valve 57 and the vent 16, and maintains the inside of the cylinder chamber 18a at a low pressure, for example, a pressure of 1.5 kg f'/cIa. In addition, high pressure (4k
gf/cJ) is supplied, and thereby the pressure accumulating chamber 2 is maintained at a fluid pressure sufficient to operate the cylinder body 1 at high speed. And the solenoid 34 of the three-way switching valve 3
is in a demagnetized state, and the movable disk 32 is pressed against the valve seat 31 by the spring member 33, so that the pressure accumulation chamber 2 and the head-side cylinder chamber 18b are cut off. Similarly, the solenoid 46 of the auxiliary control valve 4 is also in a demagnetized state, so the inflow port 41 is closed, and the outflow port 42 and the discharge port 4 are closed.
3 are in communication, and the head side cylinder chamber 18b is open to the atmosphere.

Next, when the solenoid 34 of the three-way switching valve 3 is energized and energized, the movable disk 32 moves away from the valve seat 31 against the spring member 33 and is attracted to the fixed iron core 35 . As a result, when the valve port 31a opens as the movable disk 32 moves away from the valve seat 31, the high pressure fluid in the pressure accumulator 2 flows into the passage 3.
5a through the valve port 31a of the valve seat 31 into the head-side cylinder chamber 18a, causing the piston 13 to rapidly advance toward the rod side shown by arrow A in FIG.

Note that in order to obtain high responsiveness of the three-way switching valve 3, a large current is temporarily applied to the excitation coil 36. Coil 36 at this time
The current value to be applied is 600A, and the current duration is 100m5.
It is ec.

Furthermore, at the same time as the three-way switching valve 3 is energized, the solenoid 46 of the auxiliary control valve 4 is also energized, thereby causing the spool 45
is activated to communicate the inflow port 41 and the outflow port 42, and the high pressure (5 kgf/cnl) fluid from the fluid pressure source 7 is passed through the passage 52. It flows into the head side cylinder chamber 18b through the ports 41 and 42 and the passage 11a. The fluid pressure at this time hardly functions to move the piston 13 rapidly forward toward the rod side, but is used to stably hold the piston 13 when it reaches the end of its stroke.

FIG. 5 shows the displacement of the piston 13 (not shown, but corresponds to an emergency shutoff valve of an ultra-high vacuum system connected to the piston 13), the rod, and the head-side cylinder chamber 18a.

The pressure change of 18b is expressed from the actual III value.

As is clear from the characteristic curve I in FIG. 5, immediately after the three-way switching valve 3 is opened, the pressure in the head-side cylinder chamber 18b is almost zero, and at the time of O,'2m5ec, it suddenly rises to 0. At the time of 25 m5ec, the air pressure reaches 4 kgf/c+a, which is equal to the supply air pressure. Then, when the piston 13 starts moving forward, the pressure in the head side cylinder chamber 18b suddenly drops to about 3 kgf/crA as shown in the characteristic curve (2), and the characteristic curve (2) changes according to the forward displacement of the piston 13 shown in the characteristic curve (H) below. It becomes like this.

On the other hand, the rod side cylinder chamber 1 due to the advance of the piston 13
As the volume of 8a decreases, the pressure inside the cylinder increases to 5th.
As shown in the characteristic curve (■) in the figure, the prepressure gradually increases from the prepressure point of < 1.5 kgf/cnl.

Then, after the opening command is given to the three-way switching valve 3, approximately 0
．． When 73 m5ec has elapsed, as is clear from the characteristic curve (■), the pressure in the cylinder chamber 8a on the rond side becomes greater than the pressure in the cylinder chamber 18b on the head side, and the pressure reaches its maximum just before the piston 13 reaches the end of its stroke. (4 kg f/a+) When this pressure is reached, the movable disk 54d of the check relief valve 54, which uses this as the pilot pressure, moves within the passage 54a toward the port 56, opening the exhaust opening of the valve seat member 54b. Therefore, the compressed air in the rod side cylinder chamber 18a is discharged to the atmosphere through the pilot passage 58, the discharge passage 54c and the variable throttle valve 55.
As shown in the characteristic curve (2), the pressure at a is gradually decreased from the highest pressure point and changes to a low fluid pressure level from the fluid pressure supply source 8.

That is, in FIG. 5, the region S1 of the front stage surrounded by the characteristic curve 1 and
), and the region S2 in the latter stage becomes the kinetic absorption energy for braking against the high-speed forward movement of the piston 13, which effectively alleviates the impact at the end of the stroke of the piston 13□, which is moved forward at high speed, and at the same time serves as a check. The relief valve 54 opens and the pressure inside the rod side silling chamber 8a is controlled by the variable throttle valve 55.
The pressure inside the cylinder chamber 18a is gradually reduced as shown by the characteristic curve (■) in FIG.
This allows the piston 13 to smoothly move to the stroke end without causing a bouncing phenomenon. Therefore, the piston 13 has a smooth displacement characteristic without a bound phenomenon as shown in the characteristic curve H. Moreover, a load of 310 g is connected to the piston 13, that is, an emergency shutoff valve of an ultra-high vacuum system is connected to the piston 13, and the piston 13 is opened. As a result of actually measuring the time required to complete the fully closing operation, it was confirmed that the time required to complete the fully closing operation was less than 1O, 85m5ec. This is because the braking kinetic absorption energy shown in area S2 in FIG. 5 can be reliably generated with respect to the high-speed forward kinetic energy of the piston 13.

To return the piston 13, which has been moved forward to the stroke end, to the backward end shown in FIG.
The cylinder chamber 18b is opened to the atmosphere through the exhaust port 43. Therefore, the low-pressure fluid supplied from the external fluid pressure source 8 is constantly supplied to the cylinder chamber on the rond side through the check relief valve 54. 8a, thereby moving the piston 13 to the right side in Fig. 2 and keeping it in the state shown in Fig. 2.At this time, the discharge passage 54c of the check relief valve 54 is closed by the movable disk 54d. will be accomplished.

In the above embodiment, a case has been described in which the variable throttle valve 55 is used to stop the piston 13 smoothly without causing a bounce phenomenon in the stroke. In this case, there is an advantage that it is possible to compensate for the condition of the load connected to the piston 13, the cylinder device, and other machining and assembly errors, but the present invention is limited to those using such a variable throttle valve. Alternatively, it may be a fixed orifice. Further, the auxiliary control valve 4 may be a manual three-way switching valve. Furthermore, the IJ-F valve 54 constituting the cushion pressure control mechanism 5 is not limited to that of the embodiment. Furthermore, it goes without saying that the impact mitigation and bounce prevention means of the present invention can be applied not only to high-speed cylinder devices of 6000 mm/sec but also to cylinder devices of 6000 mm/sec or less.

B) Effects of the Invention As described above, according to the present invention, the cylinder chamber on the side where the volume decreases as the piston of the fluid pressure cylinder moves forward is held in a prepressure state, and the cylinder chamber on the side where the volume decreases is evacuated using the prepressure pressure. It is possible to control the amount of kinetic energy absorbed at the end of the piston's stroke and the bounce phenomenon by using a cushion pressure control mechanism that has a valve mechanism that closes the passage and opens with the pressure in the volume reduction chamber as the piston moves forward, and an exhaust throttle means. As a result, even in a fluid cylinder that operates at a high speed of about 6000 mm/sec, it is possible to reliably cushion the impact at the end of its stroke, and also prevent the bouncing phenomenon, and moreover, effective in cushioning the fluid cylinder with a short stroke. There are effects that can be achieved.

[Brief explanation of drawings]

Fig. 1 is a principle configuration diagram of a fluid pressure cylinder device equipped with a cushioning device according to the present invention, Fig. 2 is a longitudinal cross-sectional side view showing a specific embodiment of a cylinder device having a cushion device of the present invention, and Fig. 3 2 is a sectional view taken along line III--III in FIG. 2, 4- is an enlarged sectional view of the three-way switching valve portion of the present invention, and FIG. 5 is a characteristic diagram showing experimental results of the device of the present invention. , 1... Cylinder body, 11... Cylinder tube, 13... Piston, 14... Piston rod, 1
8a... Rod side cylinder chamber, 18b... Head side cylinder chamber, 2... Pressure accumulation chamber, 3... Electromagnetic three-way switching valve, 31... Valve seat, 32... Movable disk, 33・
... Spring member, 34... Solenoid, 4... Electromagnetic auxiliary control valve, 5... Cushion pressure control mechanism, 54...
・Check relief valve, 55...variable throttle valve, 6,7
...High pressure fluid pressure source, 8...Low pressure fluid pressure source. Patent applicant: Kuroda Seiko Co., Ltd.
Toshiba Corporation - Agent Patent Attorney Fumi Furuya and Wang, 1. Figure 1 Procedural Amendment (帥6゜December 24, 1985 2, Title of Invention: Fluid Pressure Cylinder Cushion Device 3, Amendment) Relationship with case involving a person who commits a patent application / Patent applicant address 239 Shimohirama, Saiwai-ku, Kawasaki City Name Black 1) Seiko Co., Ltd. (and 114 others)
Ifu I am corrected as "room". (2) Correct ``Rod side cylinder chamber 18tz'' in the 9th line of 11th to ``Head side cylinder chamber 18tz''. "I corrected myself." (4) Page 15, line 12' (5Kg f/ c++t) J' (4Kg f
/ Cl1l) Correct it as J. (5) On page 15, line 13, "Aisle 11a" is corrected to "Aisle 11b." (6) Figures 1, 3, and 4 are corrected as shown in the attached sheet.

Claims (2)

[Claims] (1) A high-pressure fluid source that operates the piston at high speed is connected to one end of the cylinder body via a switching valve, and a load is connected to the piston rod connected to the piston, and the load is actuated by the forward movement of the piston. In the fluid pressure cylinder, a low pressure fluid source for maintaining the cylinder chamber in a prepressure state is connected to the cylinder chamber on the side whose volume decreases as the piston moves forward, and the low pressure fluid source is connected to the exhaust passage of the cylinder chamber on the side where the volume decreases. A check relief valve for generating the amount of kinetic absorption energy that closes due to the fluid pressure of the piston and opens as a pilot pressure when the fluid pressure in the cylinder chamber on the volume reduction side exceeds a set value as the piston moves forward at high speed; 1. A cushion device for a fluid pressure cylinder, comprising a throttle means for restricting the amount of fluid pressure discharged from a cylinder chamber on the volume reduction side through a relief valve. (2) The cushioning device for a fluid pressure cylinder according to claim 1, wherein the throttle means is comprised of a variable throttle valve.