KR20020017701A - Hydraulic actuator - Google Patents

Abstract

PURPOSE: A hydraulic actuator is provided to improve reliability by reciprocating linearly and rotating actively, and to prevent operating oil from leaking with simple structure. CONSTITUTION: A hydraulic actuator is composed of a cylinder(10) having a compartment(12), first and second ports(20,22) formed at both sides of an outer wall, and third and fourth ports(24) in the middle of the outer wall; a piston(30) having a first piston part(32) and a second piston part(34) reciprocating linearly between first and second ports, a third eccentric piston part(36) fixed between first and second piston parts, a piston rod fixed in the second piston part, and a channel(40) in the third eccentric piston part; and a rotating blade installed in the channel of the piston to move and to turn the piston by operating oil through third and fourth ports. The piston is reciprocated linearly with supplying oil through first and second ports, and turned with supplying oil through third and fourth ports. Oil leak is prevented with simple structure.

Description

Hydraulic actuator {HYDRAULIC ACTUATOR}

The present invention relates to a hydraulic actuator, and more particularly, to a hydraulic actuator capable of performing a parallel reciprocating motion and a rotary motion by a single piston.

As is well known, the hydraulic actuator includes a cylinder and a piston or movable vane for moving the inside of the cylinder, and is operatively connected to the oil tank, the hydraulic pump and the servovalve device to convert the pressure energy of the hydraulic oil into mechanical energy. Construct a hydraulic system. In such a hydraulic system, when a high pressure hydraulic oil is supplied from the hydraulic tank to the cylinder of the hydraulic actuator by the driving of the hydraulic pump, the piston or the movable vane performs a linear reciprocating motion, a rotary motion, or a rocking motion.

The linear reciprocating hydraulic actuator of the prior art moves a piston inside a cylinder in a desired direction by supplying high pressure to one side of the cylinder and removing pressure on the other side, and one end of which is fixed to the piston and extends outside the cylinder. It is a device to make desired linear motion by connecting load to rod. By appropriately adjusting the pressure difference between both sides of the piston, the piston rod is moved forward and stop.

In addition, in the rotary motion hydraulic actuator, the cylinder is partitioned by a partition plate and a movable vane, and the output shaft installed in the movable vane is rotated by rotating the movable vane due to the pressure difference of the hydraulic oil acting on both sides of the movable vane. It is configured to. In addition, a seal is provided between the cylinder and the movable vane to prevent leakage of hydraulic oil.

However, the special hydraulic system requires the use of a single hydraulic actuator capable of performing both a linear reciprocating motion and a rotary motion, but it is not easy to develop a hydraulic actuator capable of performing both a linear reciprocating motion and a rotary motion simultaneously. In particular, in the case of the rotary motion there is a problem that the internal leakage through the seal can not occur to stop the hydraulic actuator for a long time. Accordingly, there is a disadvantage in that internal leakage must be compensated for in circuit or mechanically. In addition, in the case of rotary actuator rotating a certain range, the drive shaft transmits pure rotational force and radial load or thrust load acts directly on the shaft because of fear of the deformation of the internal seal. Careful handling is required to avoid. Accordingly, a single hydraulic actuator capable of performing both a linear reciprocating motion and a rotating motion has a limit in the leakage leakage characteristics of the seal, which is not practically used.

Accordingly, the present invention has been made to solve various problems of the prior art as described above, an object of the present invention is to provide a hydraulic actuator capable of parallel linear reciprocating motion and rotational motion.

Another object of the present invention to provide a hydraulic actuator capable of smoothly performing a rotational movement.

Still another object of the present invention is to provide a hydraulic actuator that can prevent internal leakage of hydraulic fluid and ensure operability and reliability.

In order to achieve the above objects, the hydraulic actuator according to the present invention has a compartment, and a first port and a second port are formed at both ends of the outer wall, and the third port and the fourth port are formed by being spaced apart by a predetermined distance from the center of the outer wall. A cylinder; Between the first piston part and the second piston part and the first piston part and the second piston part which are linearly reciprocated between the first port and the second port of the cylinder, A piston having a third eccentric piston portion and a piston rod fixed to the second piston portion, wherein at least one channel is formed on an outer surface of the third eccentric piston portion; It is mounted so as to be movable in at least one channel of the piston, and consists of a rotating blade for rotating the piston by the operating oil supplied through the third port and the fourth port.

1 is a cross-sectional view showing a hydraulic actuator of the present invention,

2 is a cross-sectional view taken along line II of FIG. 1;

3 is a cross-sectional view taken along the line II-II of FIG. 1;

4a and 4b is a cross-sectional view showing a linear reciprocating motion of the hydraulic actuator according to the invention,

5a and 5b is a cross-sectional view showing a rotational movement of the hydraulic actuator according to the invention,

6 is a cross-sectional view showing a modified embodiment of the hydraulic actuator according to the present invention.

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

10: cylinder 12: compartment

20: first port 22: second port

24: third port 26: fourth port

30: piston 32: first piston portion

34: 2nd piston part 36: 3rd eccentric piston part

38: central compartment 40: channel

42: pilot passage 48: valve chamber

50: check valve 52: check ball

54: spring 60: rotating blade

Hereinafter, preferred embodiments of the hydraulic actuator according to the present invention will be described in detail with reference to the accompanying drawings.

1 to 6 are views for explaining the hydraulic actuator according to the present invention.

First, referring to FIG. 1 and FIG. 2 together, the hydraulic actuator of the present invention includes a cylinder 10. The first cover 14 and the second cover 16 are fixedly mounted at both ends of the cylinder 10 so as to form the compartment 12. The outer walls of the first cover 14 and the second cover 16 are fixed to the outer wall of the first cover 14 and the second cover 16. The first port 20 and the second port 22 to which the hydraulic line is connected are formed. The third port 24 and the fourth port 26 to which the hydraulic lines are connected are formed at predetermined intervals along the circumferential direction at the center of the outer wall of the cylinder 10.

As shown in FIGS. 1 to 3, the hydraulic actuator includes a piston 30 capable of linearly reciprocating and rotating the compartment 12 of the cylinder 10. The piston 30 is fixedly eccentrically mounted between the first piston portion 32 and the second piston portion 34 and the first piston portion 32 and the second piston portion 34 disposed at both ends. It consists of three eccentric piston parts 36. The lower portion of the outer surface of the third eccentric piston portion 36 is in contact with the inner wall of the cylinder 10, and the upper portion of the outer surface and the inner wall of the cylinder 10 are the third port 22 and the fourth port 24 of the cylinder 10. And a central compartment 38 in communication with each other. A channel 40 extending toward the central compartment 38 is formed at an upper portion of the outer surface of the third eccentric piston portion 36, and a pilot passage 42 extending from the bottom of the channel 40 to the first piston portion 32. ) Is formed.

The piston rod 44 is fixed to the second piston portion 34 of the piston 30 through the hole 18 of the second cover 16, and the inner wall of the cylinder 10 and the first of the piston 30 are fixed. And a plurality of seals 46 for preventing leakage between the second piston portions 32 and 34 and between the holes 18 of the second cover 16 and the piston rod 44. In the present embodiment, a single rod type hydraulic actuator including only one piston rod 44 is illustrated, but a double rod type hydraulic actuator in which the piston rod 44 is disposed on both sides may be configured.

In addition, a valve chamber 48 having a valve seat 48a is formed in the first piston portion 32 so as to communicate with the pilot passage 42. The valve chamber 48 has a check valve for controlling the flow of hydraulic oil ( 50) is provided. The check valve 50 serves to prevent backflow of hydraulic oil from the pilot passage 42 into the compartment 12. Such check valve 50 includes a check ball 52 for opening and closing the pilot passage 42, a spring 54 for biasing the check ball 52 in the closing direction of the pilot passage 42, and a valve chamber 48. It is composed of a plug 56 is coupled to the support (56) is formed with a hole (56a) for supporting the spring 54 and in direct communication with the pilot passage (42).

Referring to FIGS. 1 and 2 again, the rotary blade 60 is mounted to the channel 40 of the third eccentric piston 36 so that the rotary blade 60 is movable, and the upper end of the rotary blade 60 passes through the pilot passage 42. It is always in close contact with the inner wall of the cylinder 10 by the pilot pressure (Pilot Pressure) acting through. The upper end of the rotating blade 60 is formed of a spherical surface 62 to minimize the friction area with the inner wall of the cylinder (10). In addition, the length of the rotary blade 60 is formed longer than the depth of the channel (40). Therefore, when the rotary blade 60 does not operate or is in a neutral state, the lower end is spaced apart from the bottom of the channel 40 by a predetermined distance. When the rotating blade 60 rotates together with the third eccentric piston 36, the lower end of the rotating blade moves to the inside of the channel 40, and as shown in FIGS. 5A and 5B, the rotating blade 60 When the lower end of the in contact with the bottom of the channel 40, the rotary blade 60 stops without further rotation by the wedge action generated between the inner wall of the cylinder (10).

6, a modified embodiment of the hydraulic cylinder of the present invention shows a configuration in which the rotating blade 60 rotates 360 degrees continuously without stopping. 6, the third port 24 and the fourth port 26 to which the hydraulic lines are connected are formed at equal intervals along the circumferential direction at the center of the outer wall of the cylinder 10, and the third eccentric piston portion ( At the upper portion of the outer surface of 36), four channels 40 open toward the central compartment 38 are formed at equal intervals along the circumferential direction.

Each of the channels 40 of the third eccentric piston portion 36 is rotatably mounted with a rotation blade 60, and the rotation blade 60 is rotated in response to the rotation of the rotation blade 60. The length of the rotary blade 60 is formed to be equal to or shorter than the depth of the channel 40 so as to be completely immersed in the channel 40 without protruding to the outside. And, the pilot passage 42 for providing the pilot pressure is formed to be located in the center between the four channels (40). Accordingly, the spherical surface 62 of the rotating blade 60 protrudes outward from the channel 40 by the pilot pressure acting through the pilot passage 42 in the same operation as described above to closely adhere to the inner wall of the cylinder 10. do. In addition, when the rotating blade 60 rotates together with the third eccentric piston portion 36, the lower end of the rotating blade 60 moves to the inside of the channel 40 and the third eccentric piston portion is formed on the inner wall of the cylinder 10. In the position where the lower outer surface of 36 is in contact, it is completely immersed in channel 40. In this embodiment, the channel 40 and the rotation blade 60 has been described that four configuration, but their number and position can be changed as appropriate.

The operation of the hydraulic actuator according to the present invention having the configuration as described above will now be described.

1 and 4A and 4B, the hydraulic oil is supplied to the compartment 12 by the hydraulic supply device (not shown) through the first port 20 of the cylinder 10 and the second port 22. When the hydraulic oil is discharged from the compartment 12 through), the piston 30 is discharged from the first port 20 by the pressure difference between the hydraulic oil acting on the first piston part 32 and the second piston part 34. Movement toward 2 port (22). At this time, the piston rod 44 linearly moves out of the cylinder 10 through the hole 18 of the second cover 16.

On the other hand, when the hydraulic oil is discharged from the compartment 12 through the first port 20 of the cylinder 10 and supplied to the compartment 12 through the second port 22, the piston 30 is supplied to the second port 22. The piston rod 44, which moves toward the first port 20, moves outward of the cylinder 10, moves inward. As such, the piston 30 linearly reciprocates the inside of the cylinder 10 by the hydraulic oil alternately supplied to the compartment 12 through the first port 20 and the second port 22 of the cylinder 10. do. The pressure of the hydraulic oil supplied to the compartment 12 through the first port 20 and the second port 22 of the cylinder 10 is equal to the first piston part 32 and the second piston part 34. The piston 30 is stopped.

Next, referring to FIGS. 2 and 5A and 5B, the working oil is supplied to the central compartment 38 through the third port 24 of the cylinder 10 and the central compartment 38 through the fourth port 26. ), The rotary blade 60 rotates clockwise from the third port 24 toward the fourth port 26 by the pressure difference of the hydraulic oil acting on both sides, and the rotary blade 60 As a result, the third eccentric piston portion 36 of the piston 30 also rotates clockwise. At this time, the rotating blade 60 is maintained in close contact with the inner wall of the cylinder 10 by the pilot pressure acting through the pilot passage 42 as the upper end 62 as described above, the lower end of the third It is immersed into the channel 40 of the eccentric piston portion 36 and rotates together with the third eccentric piston portion 36. When the lower end of the rotary blade 60 abuts the bottom of the channel 40 and further immersion into the channel 40 is stopped, the rotary blade 60 moves to a cylinder (a position close to the fourth port 26). By the wedge action generated between the inner wall of 10) the rotary blade 60 is stopped no longer rotated and stopped.

On the contrary, when the hydraulic oil is supplied to the central compartment 38 through the fourth port 26 of the cylinder 10 and discharged from the central compartment 38 through the third port 24, the rotating blade 60 is made of silver. It rotates counterclockwise from the 4 port 26 toward the 3rd port 24, and the 3rd eccentric piston part 36 of the piston 30 also rotates counterclockwise by rotation of the rotating blade 60. FIG. . In addition, the rotating blade 60 stops by being constrained and no longer rotates at a position close to the third port 24 in the same operation as described above.

In this way, the piston 30 is rotated or oscillated by the hydraulic oil alternately supplied to the central compartment 38 through the third port 24 and the fourth port 26 of the cylinder 10. When the pressure of the hydraulic oil supplied to the central compartment 38 through the third port 24 and the fourth port 26 of the cylinder 10 is the same, the piston 30 is stopped. In the embodiment of the present invention, the linear reciprocating position and the rotational position of the piston 30 can be varied by controlling the supply of the hydraulic oil, and the linear reciprocating position for the linear reciprocating motion or the linear reciprocating position for the rotating motion. Can be varied.

Referring to FIGS. 1 and 2, the rotary blade 60 partially accommodated in the channel 40 of the third eccentric piston portion 36 may be formed in the cylinder 10 by a pilot pressure applied from the pilot passage 42. It closely adheres to the inner wall. The lower portion of the outer surface of the third eccentric piston 36 is in close contact with the inner surface of the cylinder 12 by the pressure of the working oil acting on the central compartment 38. Thus, leakage in the central compartment 38 is effectively prevented when the piston 30 rotates.

As shown in FIG. 6, when four channels 40 are formed in the third eccentric piston portion 36, and the rotary blades 60 are mounted so as to be fully immersed in each of the channels 40, The rotary blade 60 rotates without being restrained by the inner wall by the hydraulic oil supplied through the third port 24 and the fourth port 26 of the cylinder 10. Thus, the piston 30 can rotate 360 degrees continuously.

The embodiments described above are merely illustrative of the preferred embodiments of the present invention, the scope of the present invention is not limited to the described embodiments, it is within the technical spirit and claims of the present invention Various changes, modifications, or substitutions will be made by those skilled in the art, and such embodiments should be understood to be within the scope of the present invention.

As described above, according to the hydraulic actuator according to the present invention, the linear reciprocating motion of the piston by the supply of the hydraulic oil through the first port and the second port of the cylinder, and the supply of the hydraulic oil through the third port and the fourth port By this, the rotational movement of the piston can be parallel. In addition, the leakage of the hydraulic oil is prevented by a simple configuration, and the effect is excellent in operability and reliability.

Claims (5)

A cylinder having a compartment, wherein a first port and a second port are formed at both ends of the outer wall, and a third port and a fourth port are formed at a center of the outer wall and separated from each other by a predetermined distance; The first piston part and the second piston part between the first piston part and the second piston part and the first piston part and the second piston part which linearly reciprocate between the first port and the second port of the cylinder. And a piston having an eccentrically fixed third eccentric piston portion and a piston rod fixed to the second piston portion, wherein at least one channel is formed on the outer surface of the third eccentric piston portion; And a rotating blade mounted to be movable in at least one channel of the piston, the rotating blade rotating the piston by working oil supplied through the third port and the fourth port. 2. The method of claim 1, wherein when the channel is one, the channel is constrained to the inner wall of the cylinder at a position where the upper end of the rotary blade is close to the third port and the fourth port to limit the rotational movement of the piston. Hydraulic actuators are designed to have the depth of The hydraulic actuator of claim 1, wherein the channel is formed to have a depth at which the rotary blade can be fully immersed when the channel is plural. According to any one of claims 1 to 3, wherein the first piston portion is formed with a pilot passage for communicating the compartment and the channel to provide a pilot pressure so that the rotating blade is in close contact with the inner wall of the cylinder And a valve means provided in the pilot passage to control the pilot pressure. 5. The hydraulic actuator according to claim 4, wherein the valve means comprises a check ball for opening and closing the pilot passage and a spring for biasing the check ball in a direction for closing the pilot passage.