JPH0596513U - Cylinder cushion device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] In the cushion section, the effective thrust area of the piston is reduced, the generation of energy by the thrust is reduced to reduce the burden on the cushion, and the two throttle holes of the piston are shared. To reduce the size of the piston. [Structure] A small piston 5 is slidably fitted in a hollow hole of a hollow piston 6 having communication holes 18 and 19 at both ends, and a hollow throttle mandrel 8 having a through hole 12 is provided in the communication hole and the hollow hole. The head cover 1 communicates with the inside opening of the head cover 1 and the outside through a needle valve 11 with a check valve. When the hollow piston enters the cushion section, the hollow throttle mandrel abuts the small piston to stop the small piston, and the effective thrust area of the piston decreases. At the same time, the communication between the through hole of the hollow throttle mandrel and the exhaust side chamber is blocked, the flow rate of the fluid flowing out of the exhaust side chamber is adjusted by the needle valve with check valve, the back pressure in the exhaust side chamber rises, and the hollow piston decelerates. To be done.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a cushion device that reduces the speed of a piston at the end of a stroke in a fluid pressure cylinder used to operate various machines in order to absorb impact.

[0002]

[Prior Art]

 FIG. 4 shows a conventional cylinder cushion device. A slide block 32 is slidably fitted in the cylinder tube 31, and an end block 33 is fixed to an end of the cylinder tube 31. A throttle hole 34 is opened at both ends of the slide block (piston) 32, and a throttle packing 35 is arranged in an annular groove at the opening of the throttle hole 34. A port 36 that opens to the outside is formed in the end block 33, and a needle valve with a check valve (not shown) is installed in the passage that connects the port 36 and the vicinity of the circumference of the inner surface of the end block 33. To be done. At the center of the inner surface of the end block 33, a cylindrical throttle mandrel 37 is fixed substantially vertically to the inner surface of the end block 33, and between the inside of the throttle mandrel 37 and the port 36, there is an end. It is connected by a passage in block 33.

In the conventional cushion device for a cylinder, when the slide block 32 moves to the cushion section, the throttle mandrel 37 enters the throttle hole 34, and the throttle packing is provided between the exhaust side chamber and the passage in the throttle mandrel 37. Blocked by 35. The discharge of air in the exhaust side chamber is adjusted by the needle valve of the needle valve with check valve, and the air in the exhaust side chamber is compressed by the kinetic energy of the table 38 and load connected to the slide block 32 and the energy of the thrust. The pressure rises and the deceleration force is exerted. In the conventional cylinder cushion device, it is necessary to absorb both the energy due to the motion energy and the energy due to the thrust in the cushion section, so that the amount of energy to be absorbed is large. Further, since the throttle holes 34 are provided on both sides of the slide block 32, the piston becomes large.

[0004]

[Problems to be solved by the device]

 The present invention solves the above-mentioned drawbacks of the prior art. In the cushion section, the effective thrust area of the piston is reduced, the generation of energy due to the thrust is reduced, and the load on the cushion is reduced. An object is to reduce the size of the piston by using a common throttle hole (hollow hole).

[0005]

[Means for Solving the Problems]

 According to the present invention, in order to achieve the above object, in a cylinder cushion device, communication holes are formed at both ends of a hollow piston, and a small piston is slidably fitted in the hollow hole of a hollow piston and fixed to a head cover. The hollow throttle mandrel is installed so that it can be inserted freely into the communication hole and the hollow hole, the through hole of the hollow throttle mandrel is communicated to the outside, and the needle cover inner valve opening and the needle valve with check valve I was able to communicate through. In interpreting the present invention, the following matters should be considered. The cylinder cushion device of the present invention can be installed on both sides or one side of the cylinder tube. The working medium used in the cylinder cushion device of the present invention includes not only air but all kinds of fluids.

[0006]

[Action]

 When the hollow piston enters the cushion section, the hollow throttle mandrel is inserted into the communication hole and the hollow hole and contacts the small piston, and the movement of the small piston is stopped, so that the effective thrust area of the piston is reduced. At the same time, the communication between the through hole of the hollow throttle mandrel communicating with the atmosphere and the exhaust side chamber is blocked, and the flow rate of the fluid flowing out of the exhaust side chamber is adjusted by the needle valve with a check valve. The back pressure in the room rises and the moving speed of the hollow piston is reduced.

[0007]

1 to 3 show a cylinder cushion device according to an embodiment of the present invention, and only one of the cylinder cushion devices installed at both ends of an air cylinder is shown. A rodless hollow piston 6 is slidably fitted in the cylinder tube 3, and a head cover 1 is fixed to an end of the cylinder tube 3. The hollow piston 6 has a bottomed cylindrical piston body 15, and the sleeve 10 is fitted to the inner surface of the piston body 15. The small piston 5 is slidably fitted to the inner surface of the sleeve 10, and the opening of the piston body 15 is closed by a lid 17. Communication holes 18 and 19 having a diameter smaller than the inner diameter of the sleeve 10 are formed in the bottom portion 16 and the lid body 17 of the piston main body 15, respectively, and the annular first throttle packing 7 is formed in the annular concave portion on the inner surface of the communication holes 18 and 19. And the second diaphragm packing 9 are respectively arranged. Annular packings 4A and 4B are provided in annular recessed grooves on both sides of the small piston 5 in the vicinity of the circumference. The packing 4A contacts the inner surface of the bottom portion 16, and the packing 4B fits on the inner surface of the lid 17. It is in the contact position.

A port 13 that opens to the outside is formed in the head cover 1, and a needle valve 11 with a check valve is arranged in a first passage 20 that connects the port 13 and the vicinity of the circumference of the inner surface of the head cover 1. To be done. At the center of the inner surface of the head cover 1, a hollow diaphragm mandrel 8 having a bottomed shape is fixed substantially vertically to the inner surface of the head cover 1 (the opening of the hollow diaphragm mandrel 8 faces the head cover 1). The inside of the mandrel 8 and the port 13 are connected by a second passage 21 in the head cover 1. The hollow throttle mandrel 8 is disposed so as to be freely inserted into the first throttle packing 7 and the sleeve 10 of the hollow piston 6, and the hollow throttle mandrel 8 and the first throttle packing 7 are slidably inserted in a sealed state. A plurality of through holes 12 are formed near the tip (right end in the figure) of the hollow constricting mandrel 8. An annular damper 2 is arranged in an annular groove on the inner surface of the head cover 1, and the damper 2 can be brought into contact with the outer surface of the bottom portion 16 of the hollow piston 6.

The operation of the embodiment of the present invention will be described. FIG. 1 shows a state before the hollow piston 6 enters the cushion section, FIG. 2 shows an initial state of the cushion section, and FIG. 3 shows a state where the hollow piston 6 reaches the stroke end. In the state shown in FIG. 1, compressed air is supplied to the filling side (right side) chamber of the hollow piston 6 and the pressure is P1, and the exhaust side (left side) chamber of the hollow piston 6 is the first passage 20 and the through hole 12. It is communicated with the atmosphere through the second passage 21 and the port 13, and the pressure is P2. The pressure P1 also acts on the filling side of the small piston 5, the small piston 5 is located at the left end (advancing end) in the hollow piston 6, and the packing 4A of the small piston 5 is pressed against the inner surface of the bottom portion 16. It is sealed. The piston 6 advances (moves leftward) toward the exhaust side chamber at a predetermined speed.

When the piston 6 moves forward and moves to the cushion section, as shown in FIG. 2, the hollow throttle mandrel 8 enters into the communication hole 18 of the hollow piston 6, the first throttle packing 7, and the sleeve 10, and the hollow The tip of the throttle mandrel 8 contacts the small piston 5, and the hollow throttle mandrel 8 receives the force acting on the small piston 5. Therefore, the thrust acting on the hollow piston 6 is calculated as "(effective thrust (pressure receiving) area A2 of the small piston 5) x (pressure P1 on the filling side of the hollow piston 6)-(outer diameter cross-sectional area A3 of the hollow throttle mandrel 8). ) × (pressure P2 on the exhaust side of the hollow piston 6) ”, the conventional thrust“ (effective thrust area A1 of the hollow piston 6) × [(pressure P1 on the filling side of the hollow piston 6)-(hollow piston 6 pressure on the exhaust side P2)]]. At the same time, the communication between the through hole 12 of the hollow throttle mandrel 8 and the exhaust side chamber is blocked by the outer surface of the hollow throttle mandrel 8 and the first throttle packing 7, and the air discharge from the exhaust side chamber is checked by a needle valve with a valve. To be done. The energy in the load connected to the hollow piston 6 and the energy generated by the thrust force compress the air in the exhaust side chamber, increasing the pressure in the exhaust side chamber and decelerating the hollow piston 6. Thus, the remaining thrust energy and kinetic energy are absorbed until the stroke end of the hollow piston 6.

The hollow piston 6 is decelerated in the cushion section, and as shown in FIG. 3, the outer surface of the bottom portion 16 of the hollow piston 6 contacts the damper 2 and reaches the stroke end. At this time, a slight gap is set between the filling side (right side) side of the small piston 5 and the inner side surface of the lid 17, so that the collision between the small piston 5 and the lid 17 does not occur. It won't happen. When the exhaust side is changed to the filling side by switching the directional control valve, compressed air flows into the sleeve 10 through the port 13, the second passage 21 and the through hole 12, and the small piston 5 moves inside the lid 17. Is pressed against. Further, compressed air flows into the filling side chamber through the port 13, the first passage 20, and the needle valve with a check valve, and acts on the outer surface of the bottom portion 16 of the hollow piston 6. Therefore, the hollow piston 6 starts moving rightward in the figure. Since the cylinder cushioning device similar to that described above is also arranged on the opposite side of the head cover 1 of the cylinder tube 3, the hollow piston 6 has the same cushioning action as described above even at the right end of the cylinder tube 3. receive.

[0012]

[Effect of the device]

 In the present invention, since the small piston constantly contacts the hollow throttle mandrel within the cushion section, the effective thrust area of the hollow piston is reduced and the generation of energy by the thrust is reduced. Therefore, the burden on the cushion is reduced, and the movement distance required for the cushion can be shortened. Further, when the hollow throttle mandrel is inserted into the communication hole and the hollow hole of the hollow piston and comes into contact with the small piston in the hollow hole, the small piston moves. Therefore, the inside of the hollow hole of the hollow piston becomes a common space for the hollow throttle mandrel fixed to both ends of the cylinder tube, which leads to downsizing of the piston and increase of effective stroke.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylinder cushion device (a state immediately before a piston enters a cushion section) of an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a cylinder cushion device (a state immediately after a piston enters a cushion section) of an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of a cylinder cushion device (a state in which a piston arrives at a stroke end) of an embodiment of the present invention.

FIG. 4 is a vertical sectional view of a conventional cylinder cushion device.

[Explanation of symbols]

 1 head cover 5 small piston 6 hollow piston 8 hollow throttle mandrel 11 needle valve with check valve 12 through hole 18 through hole 19 through hole

Claims (1)

[Scope of utility model registration request] 1. A hollow throttle mandrel having communication holes formed at both ends of a hollow piston, a small piston slidably fitted in the hollow hole of the hollow piston, and a hollow throttle mandrel fixed to a head cover,
It was arranged so that it could be inserted into the communication hole and the hollow hole, the communication hole of the hollow throttle mandrel communicated with the port that opened to the outside, and the inner side opening of the head cover communicated with the outside through the needle valve with check valve. Cylinder cushion device.