KR20030039398A - Damper in hydraulic cylinder - Google Patents

Abstract

PURPOSE: A damping device of a hydraulic cylinder is provided to prevent wear of parts caused by interference of a bore and a damping rod, and precisely control discharge of an actuating fluid through an oil passage and a control pin. CONSTITUTION: A damping device of a hydraulic cylinder includes a rear cover(20) having a bore(22) opened toward an inner bore(12) of a tube(10) and an oil passage(24) communicating the bore and the inner bore; a plunger(50) having passages(52,54) communicating the bore and the inner bore; and a control pin(26) screwed from the outside of the rear cover, to control the sectional area of the oil passage. The rear cover is combined to the rear end of the tube and the plunger is installed to the bore. The passages of the plunger are gradually closed while being pushed into the bore by a piston(30). The plunger moves, with fitted into the bore and thus, wear of parts caused by interference of the bore and a damping rod is prevented and oil leakage is prevented.

Description

Damping device for hydraulic cylinders {DAMPER IN HYDRAULIC CYLINDER}

The present invention relates to a hydraulic cylinder, and more particularly to a damping device of a hydraulic cylinder for preventing the piston from hitting the rear cover during the contraction of the piston rod.

Hydraulic cylinder is a representative actuator for converting the pressure energy of the working oil into mechanical energy. This hydraulic cylinder has a tube 10 as shown in FIG. Tube 10 has an inner diameter 12, which is configured to be sealed by a front cover and a rear cover 20, not shown. And the hydraulic cylinder has a piston (30). The piston 30 is disposed in the inner diameter 12 of the tube 10 to divide the inner diameter 12 into the first chamber 12a and the second chamber 12b, and the first chamber 12a and the second chamber ( It is configured to be movable along the inside of the tube 10 by the hydraulic oil introduced into 12b). Here, a seal 32 is disposed on the outer circumferential surface of the piston 30 to maintain airtightness with the inner wall of the tube 10.

And the hydraulic cylinder has a piston rod (40). The piston rod 40 is connected to the piston 30 and extends through the front cover (not shown) to the outside. The piston rod 40 is mechanical work while repeating the expansion and contraction by the piston 30 to move along the inner diameter 12 of the tube (10).

On the other hand, the hydraulic cylinder is provided with a damping device for preventing the piston 30 and the rear cover 20 from colliding quickly in the process of the piston rod 40 is contracted to move to the inside of the tube 10. The damping device includes a bore 22 formed on the rear cover 20 and connected to an oil tank (not shown), a damping rod 34 formed on the piston 30 to be accessible to the bore 22, and a rear. An oil passage 24 for communicating the bore 22 of the cover 20 and the first chamber 12a of the tube 10, and an outer side of the rear cover 20 to adjust the cross-sectional area of the oil passage 24. It consists of a control pin 26 screwed from.

When the piston rod 40 is contracted and moved inwardly of the tube 10 according to this configuration, the damping rod 34 of the piston 30 moves simultaneously to enter the bore 22 of the rear cover 20. As the damping rod 34 enters the bore 22, only a small amount of the hydraulic oil in the first chamber 12a is discharged into the oil tank through the oil passage 24, thereby decelerating the piston 30. Here, in order to adjust the deceleration speed of the piston 30, through the adjustment pin 26 to adjust the cross-sectional area of the oil passage (24). Then, the flow rate of the hydraulic oil discharged from the first chamber 12a is adjusted to adjust the deceleration speed of the piston 30.

However, in such a conventional damping device, when the bore 22 of the rear cover 20 and the damping rod 34 of the piston 30 are not aligned with each other due to a machining error, the damping rod 34 has a bore 22. The inlet of the bore 22 and the end of the damping rod 34 interfere with each other and collide with each other in the process of being inserted therein, and the wear and tear between the bore 22 and the damping rod 34 due to frequent interference and collision. There is a problem that is promoted.

On the other hand, in view of this, the diameter of the bore 22 may be made larger than the outer diameter of the damping rod 34, but this is an additional problem that the hydraulic oil of the bore 22 is leaked due to the gap between the bore 22 and the damping rod 34. Generate. This problem is a cause of lowering the damping performance of the piston (30). In particular, the leakage of the working oil makes it difficult to control the discharge of the working oil through the oil passage 24 and the adjusting pin 26, so that the deceleration speed of the piston 30 cannot be adjusted.

In addition, the conventional damping device has been pointed out that it is difficult to expect the effect of the smooth deceleration because the deceleration speed of the piston 30 is instantaneously reduced. That is, as the damping rod 34 is inserted into the bore 22 of the rear cover 20, the piston 30 moves inwardly of the tube 10, and the speed thereof is reduced. Due to the smooth deceleration is a difficult problem.

Therefore, the present invention has been made to solve the above problems, its purpose is to prevent the wear of the bore and damping rod, such as to extend the life of the device, to prevent leakage of oil through the oil passage and the adjustment pin The present invention provides a damping device for a hydraulic cylinder that enables precise control of the amount of hydraulic oil discharged.

Another object of the present invention is to provide a damping device for a hydraulic cylinder that can gradually reduce the movement speed of the piston to realize a smooth deceleration.

1 is a cross-sectional view showing a damping device of a conventional hydraulic cylinder,

2 is a cross-sectional view showing the configuration of a damping device for a hydraulic cylinder according to the present invention;

3 is an operation diagram of the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

10: tube 12: inner diameter

20: rear cover 22: bore

24: oil passage 26: adjusting pin

30: piston 40: piston rod

50: plunger 52: main passage

54: split passage

In order to achieve the above object, the present invention provides a hydraulic cylinder having a tube having an inner diameter and a piston movably disposed at the inner diameter of the tube, the bore being coupled to the rear end of the tube and open toward the inner diameter, and the bore and the inner diameter. A rear cover having an oil passage communicating with the oil; A plunger installed in the bore, the plunger having a passage communicating the inner diameter of the bore and the tube with each other, the passage gradually being closed by being pushed into the bore by the piston; It characterized in that it comprises a control pin screwed from the outside of the rear cover to adjust the cross-sectional area of the oil passage.

Preferably, the passage of the plunger is characterized in that the main passage in communication with the bore and a plurality of divided passages communicated from the main passage to the outside of the plunger.

Hereinafter, a preferred embodiment of the damping device of a hydraulic cylinder according to the present invention will be described in detail with reference to the accompanying drawings (the same components as in the prior art are described using the same reference numerals).

2 is a cross-sectional view showing the configuration of a damping device for a hydraulic cylinder according to the present invention. First, prior to looking at the configuration of the damping device of the present invention, when looking at the configuration of the hydraulic cylinder, the hydraulic cylinder has a tube 10, the inner diameter 12 of the tube 10 is a front cover and a rear cover not shown It is configured to be sealed by 20. And the hydraulic cylinder has a piston (30). The piston 30 is disposed in the inner diameter 12 of the tube 10 to divide the inner diameter 12 into a first chamber 12a and a second chamber 12b, and the first chamber 12a and the second chamber ( It is configured to be movable along the inside of the tube 10 by the hydraulic oil introduced into 12b). Here, the seal 32 is disposed on the outer circumferential surface of the piston 30 to maintain the airtightness with the inner wall of the tube 10.

And the hydraulic cylinder has a piston rod (40). The piston rod 40 is connected to the piston 30 and extends through the front cover (not shown) to the outside. The piston rod 40 is mechanical work while repeating the expansion and contraction by the piston 30 to move along the inner diameter 12 of the tube (10).

On the other hand, the hydraulic cylinder is provided with a damping device of the present invention for preventing the piston 30 and the rear cover 20 from hitting each other. The damping device of the present invention comprises a bore 22 formed in the rear cover 20, a plunger 50 reciprocating along the bore 22, a bore 22 and a tube 10 of the rear cover 20. Oil passage 24 for communicating the first chamber 12a of the, and the control pin 26 is screwed from the outside of the rear cover 20 to adjust the cross-sectional area of the oil passage (24).

Here, the plunger 50 has a main passage 52 which communicates with the bore 22, and a plurality of split passages 54 which communicate with the outside of the plunger 50 from the main passage 52. In particular, the split passage 54 is configured to be gradually blocked or gradually opened by the inner wall of the bore 22 as the plunger 50 reciprocates along the bore 22. In the present invention, the split passage 54 is formed in a pair on both sides, but is not limited thereto, and may be formed in one or three or more according to the size of the plunger 50.

On the other hand, the plunger 50 is configured to be inserted into the bore 22 by being pressed by the piston 30 as the piston rod 40 contracts, and to the bore 22 to extend the piston rod 40. When the hydraulic oil is introduced, it is configured to protrude into the first chamber 12a by the introduced hydraulic oil. Here, the plunger 50 is configured not to be separated from the bore 22, for this purpose, the foreign exchange jaw 50a is formed on the outer circumferential surface of the plunger 50, and the inner ring jaw 22a is formed on the inner circumferential surface of the bore 22, respectively. have. When the plunger 50 moves outward of the bore 22, the inner ringing jaw 22a and the foreign exchange jaw 50a interfere with each other to prevent the plunger 50 from being separated.

Next, the operation of the present invention having such a configuration will be described with reference to FIGS. 2 and 3. First, as the hydraulic oil is introduced into the second chamber 12b, the piston 30 approaches the rear cover 20 and presses the plunger 50. At this time, as the plunger 50 moves to the inside of the bore 22 and the partition passage 54 is gradually blocked, the amount of hydraulic oil discharged through the main passage 52 is reduced, whereby the plunger 50 is the bore 22. Movement toward the inner side) is gradually reduced to smoothly decelerate with the movement of the piston (30).

When the split passage 54 of the plunger 50 is completely blocked as the plunger 50 moves further into the bore 22, the hydraulic fluid of the first chamber 12a is only supplied from the oil passage 24 and the bore. As it is discharged to the oil tank through 22, the movement of the piston 30 is slowed more slowly. As a result, the piston 30 moving toward the rear cover 20 is smoothly decelerated, whereby the deceleration of the piston rod 40 is naturally achieved.

On the other hand, if you want to adjust the deceleration speed of the piston 30, by adjusting the cross-sectional area of the oil passage 24 through the adjustment pin 26 may be adjusted the flow rate of the hydraulic oil discharged from the first chamber (12a).

Although the preferred embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to these specific embodiments, and may be appropriately changed within the scope of the claims.

The damping device of the hydraulic cylinder according to the present invention having such a configuration is to install the plunger in the bore of the rear cover movably, thereby reducing the movement of the piston through this hassle to align the bore and damping rod as in the prior art. Relieve In particular, as the plunger moves in the bore, the wear of the parts due to the interference and collision between the bore and the damping rod is prevented as much as conventionally. In addition, the plunger is tightly fitted to the bore, preventing leakage and precisely controlling the discharge of the hydraulic oil through the oil passage and the adjusting pin, thereby accurately controlling the deceleration speed of the piston.

In addition, a plunger is provided with a passage for communicating the bore with the tube, and the passage is configured to be gradually blocked as the plunger is inserted into the bore, thereby gradually reducing the amount of hydraulic oil in the first chamber, thereby reducing the movement speed of the piston. It can be gradually reduced to realize smooth deceleration.

Claims (2)

In a hydraulic cylinder having a tube (10) having an inner diameter (12) and a piston (30) movably disposed at the inner diameter (12) of the tube (10), A rear cover (20) coupled to the rear end of the tube (10) and having a bore (22) opened toward the inner diameter (12) and an oil passage (24) for communicating the bore (22) and the inner diameter (12); Is installed in the bore 22, the bore 22 and the inner diameter 12 of the tube 10 communicate with each other, the passage gradually closed by being pressed into the bore 22 by the piston 30 A plunger 50 having 52 and 54; Damping device of the hydraulic cylinder, characterized in that it comprises a control pin (26) screwed from the outside of the rear cover 20 to adjust the cross-sectional area of the oil passage (24). 2. The passages 52 and 54 of the plunger 50 communicate with the main passage 52 communicating with the bore 22, and communicate with the outside of the plunger 50 from the main passage 52. A damping device for a hydraulic cylinder, characterized in that the plurality of divided passages (54).