KR101598330B1 - Hydrostatic Servo Actuator - Google Patents

Hydrostatic Servo Actuator Download PDF

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Publication number
KR101598330B1
KR101598330B1 KR1020150038120A KR20150038120A KR101598330B1 KR 101598330 B1 KR101598330 B1 KR 101598330B1 KR 1020150038120 A KR1020150038120 A KR 1020150038120A KR 20150038120 A KR20150038120 A KR 20150038120A KR 101598330 B1 KR101598330 B1 KR 101598330B1
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KR
South Korea
Prior art keywords
cylinder tube
pocket
piston
circumferential surface
hydrostatic
Prior art date
Application number
KR1020150038120A
Other languages
Korean (ko)
Inventor
박종원
이기욱
Original Assignee
한국기계연구원
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Publication date
Application filed by 한국기계연구원 filed Critical 한국기계연구원
Priority to KR1020150038120A priority Critical patent/KR101598330B1/en
Application granted granted Critical
Publication of KR101598330B1 publication Critical patent/KR101598330B1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
    • F15B15/08—Characterised by the construction of the motor unit
    • F15B15/14—Characterised by the construction of the motor unit of the straight-cylinder type
    • F15B15/1423—Component parts; Constructional details
    • F15B15/1457—Piston rods
    • F15B15/1461—Piston rod sealings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Magnetic Bearings And Hydrostatic Bearings (AREA)
  • Actuator (AREA)

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic servo actuator that linearly reciprocates by hydraulic pressure, and more particularly, to a hydraulic actuator that minimizes friction of a piston rod contacting a cylinder tube, And more particularly, to a hydrostatic servo actuator for preventing the cylinder tube and the piston rod from being damaged, thereby extending the service life of the servo actuator and ensuring reliability.

Description

[0001] The present invention relates to a hydrostatic servo actuator,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrostatic servo actuator that linearly reciprocates by hydraulic pressure, and more particularly, to a hydraulic actuator that minimizes friction of a piston rod contacting a cylinder tube, And more particularly, to a hydrostatic servo actuator for preventing the cylinder tube and the piston rod from being damaged, thereby extending the service life of the servo actuator and ensuring reliability.

Generally, a hydraulic actuator is a device that applies a piston rod that linearly reciprocates in a cylinder, and is typically used for construction equipment and the like. Recently, the hydraulic actuator is also applied to a joint and a motion control of a robot. The hydraulic actuator is driven by a working fluid discharged from a hydraulic pump, and the discharge flow rate of the hydraulic pump is controlled in accordance with the driving degree of the hydraulic machine.

1 is a schematic cross-sectional view of a general hydraulic servo actuator 10. As shown in the figure, the servo actuator 10 includes a cylinder tube 12 in which a piston rod 11 is linearly reciprocated and a working fluid is received therein and a hydraulic pressure is generated, and a linear reciprocating motion of the piston rod 11 A manifold 14 for controlling the flow rate of the working fluid so as to control the linear reciprocating motion of the piston rod 11 and a cylinder tube 12 for controlling the flow rate of the working fluid to control the linear reciprocating motion of the piston rod 11, And a hydraulic line 16 which communicates with the manifold 14 to supply or recover the working fluid to the cylinder tube 12. [ At this time, on the servo actuator 10, frictional force is minimized on the friction parts of the cylinder tube 12 and the piston rod 11 according to the rotation of the piston rod 11, and foreign substances are prevented from flowing into the cylinder tube 12 The hydraulic pressure bearing 15 is applied. The lubricant is supplied onto the hydraulic oil bearing 15 to minimize the frictional force between the piston rod 11 and the cylinder tube 12 and to divide the inside and the outside of the cylinder tube 12 through a sealing member such as an O- So that external foreign matter is prevented from flowing into the cylinder tube 12.

However, since the hydraulic bearing 15 of the conventional servo actuator 10 described above simply supplies the lubricant to the inner surface of the hydraulic bearing 15, an oil film is not uniformly formed on the outer surface of the piston rod 11, The sealing performance of the O-ring for partitioning and sealing the inside and the outside of the cylinder tube 12 is lowered when the lubricating oil is excessively supplied, There is a problem such as a pressure loss due to leakage of the internal working fluid of the internal combustion engine and damage of the servo actuator 10 due to the inflow of external foreign substances into the cylinder tube 12. [

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a lubricating oil supply apparatus and a lubricating oil supply apparatus, which are capable of efficiently supplying an appropriate amount of lubricant to a friction portion of a piston rod and a cylinder tube, And a lubricant is supplied to the pocket, thereby smoothly forming an oil film on the piston rod.

And a sealing member at one side or both sides of the pockets in a piston rod driving direction to improve lubrication performance by preventing leakage of the lubricant and improve the sealing force of the cylinder tube.

A hydrostatic servo actuator according to the present invention is a hydrostatic servo actuator including a cylinder tube and a piston rod having one side inserted into the cylinder tube and linearly reciprocating by hydraulic pressure, An annular hydrostatic bearing mounted on the outer circumferential surface of the cylinder tube and engaged with the inner circumferential surface of the cylinder tube and having an inner circumferential surface abutting the outer circumferential surface of the piston rod; Wherein the static pressure bearing includes: a pocket formed to be recessed inward from an inner circumferential surface so that a lubricant is supplied; .

The hydraulic bearing may include a first insertion portion spaced a predetermined distance from the other side of the pocket so as to insert a first sealing member for sealing the positive pressure bearing and the piston rod, and being recessed inward from the inner circumferential surface; .

In another embodiment, the hydrostatic bearing may include a second insert which is spaced a distance from the one side of the pocket so as to insert a second sealing member for additional sealing of the hydraulic rod bearing and the piston rod, part; .

The pockets are spaced apart from each other along the longitudinal direction of the piston rod, and a plurality of the pockets are disposed along the circumferential direction of the hydraulic bearing.

The pockets are formed to be narrower inward from the inner circumferential surface of the hydraulic pressure bearing, and are formed spirally along the longitudinal direction of the piston rod.

In addition, the piston rod may include a piston accommodated in the cylinder tube and formed at one side thereof; And a rod having one side connected to the piston and the other side exposed to the outside of the cylinder tube; A piston pocket recessed inwardly on an outer circumferential surface of the piston; .

The hydrostatic servo actuator of the present invention constructed as described above improves the lubrication performance of the frictional portion between the piston rod and the cylinder tube, thereby remarkably reducing frictional force. Therefore, fine control of the piston rod is facilitated, So that a contact phenomenon can be prevented.

Further, the sealing force of the cylinder tube is improved to prevent leakage of the working fluid or the lubricant, and to prevent foreign matter from flowing into the cylinder tube, thereby preventing damage of the piston rod and the cylinder tube.

1 is a schematic sectional view of a general servo actuator
2 is a schematic cross-sectional view of a servo actuator according to an embodiment of the present invention;
FIG. 3A is a cross-sectional view of the hydrostatic bearing according to the first embodiment of the present invention
3B is a cross-sectional view of the hydrostatic bearing according to the second embodiment of the present invention
4A is a cross-sectional view taken along line AA 'of FIG. 3B according to the second embodiment of the present invention
FIG. 4B is a cross-sectional view taken along line AA 'of FIG. 3B according to the second embodiment of the present invention
5 is a cross-sectional view of a portion of a hydrostatic bearing according to various embodiments of the present invention;

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

2 is a schematic cross-sectional view of a hydrostatic servo actuator 100 (hereinafter referred to as a servo actuator) according to an embodiment of the present invention. As shown in the figure, the servo actuator 100 includes a piston rod 110, a cylinder tube 120, and a hydrostatic bearing 150.

The cylinder tube 120 may have a piston space 121 formed therein so that the piston rod 110 can rotate and a working fluid for controlling the operation of the piston rod 110 may be introduced or discharged. The cylinder tube 120 has a cylindrical shape with one side closed and the other side opened.

One end of the piston rod 110 is accommodated in the cylinder tube 120 to be reciprocated linearly, and the other end is exposed to the outside. That is, the piston rod 110 is formed on one side and includes a piston 112 accommodated in the cylinder tube 120, a rod 111 having one side connected to the piston 112 and the other side exposed to the outside of the cylinder tube 120 ). The piston 112 is formed in a cylindrical shape and has an outer circumferential surface close to the inner circumferential surface of the cylinder tube 120 and the rod 111 may be a rod type having a diameter smaller than the diameter of the piston 112. A piston pocket 115 into which a working fluid flows is formed on an outer circumferential surface of the piston 112 to minimize frictional force generated between the outer circumferential surface of the piston 112 and the inner circumferential surface of the cylinder tube 120 when the piston 112 rotates .

The piston pocket 115 is formed in a recessed shape recessed inwardly from the outer peripheral surface of the piston 112. The piston pockets 115 may be spaced apart from each other along the longitudinal direction of the piston 112. The piston pockets 115 may be formed as a closed curve along the circumferential direction of the piston 112, or may be spaced apart at equal intervals along the circumferential direction. A space through which the working fluid can flow into the outer circumferential surface of the piston 112 and the inner circumferential surface of the cylinder tube 120 through the piston pocket 115 is formed so that the piston 112 and the cylinder tube 120 can be reduced.

A hydrostatic bearing 150 may be provided on the other side of the cylinder tube 120 to minimize frictional forces generated on the outer circumferential surface of the rod 111 and the inner circumferential surface of the cylinder tube 120 when the rod 111 rotates. The outer circumferential surface of the hydrostatic bearing 150 is tightly coupled to the inner circumferential surface of the cylinder tube 120, and the inner circumferential surface of the outer circumferential surface of the hydrostatic bearing 150 is in contact with the outer circumferential surface of the rod 111. An insertion portion 151 into which a sealing member O for sealing between the piston space 121 of the cylinder tube 120 and the outside is inserted is formed on the other side of the inner circumferential surface of the hydrostatic bearing 150. The insertion portion 151 is recessed outward from the inner circumferential surface of the hydrostatic bearing 150 and is formed as a closed curve along the circumferential direction of the hydrostatic bearing 150. In addition, a pocket 152 for forming an oil film may be formed on the outer circumferential surface of the rod 111 at one side of the inner circumferential surface of the hydrostatic bearing 150. The pockets 152 are recessed outward from the inner circumferential surface of the hydrostatic bearing 150 and the hydrostatic bearings 150 may be spaced apart from one another along the longitudinal direction of the piston rod 110. The pocket 152 is configured to communicate with the lubricating oil supply means (not shown) to receive the lubricating oil. The lubricant stored in the pocket 152 is applied to the outer surface of the rod 111 in the reciprocating motion of the rod 111 in a linear reciprocating motion to form an oil film and the rod 111 and the hydrostatic bearing 150 The frictional force of the friction portion can be reduced.

Hereinafter, the detailed configuration and arrangement of the pockets 152 of the hydrostatic bearing 150 will be described in detail.

3A is a sectional view of the hydrostatic bearing 150 according to the first embodiment of the present invention, and FIG. 3B is a sectional view of the hydrostatic bearing 150 according to the second embodiment of the present invention.

3A, the hydrostatic bearing 150 includes a single sealing member. The first insertion portion 151a, in which the first sealing member 01 is received, is disposed on the other side of the inner peripheral surface of the hydrostatic bearing 150 As shown in FIG. Therefore, the pocket 152 can be formed on one side with respect to the first insertion portion 151a. The hydrostatic bearing 150 according to the first embodiment can be applied to a servo actuator having a low possibility of inflow of external foreign matter and a low hydraulic pressure.

3B, the hydrostatic bearing 150 includes a pair of sealing members. The first insertion portion 151a, in which the first sealing member 01 is received, And a second inserting portion 151b formed on the other side and receiving the second sealing member 02 is formed on one side of the inner circumferential surface of the hydrostatic bearing 150. [ Therefore, the pocket 152 may be formed between the first insertion portion 151a and the second insertion portion 151b. The hydrostatic bearing 150 according to the second embodiment improves the sealing force of the cylinder tube by constituting a plurality of sealing members when the possibility of inflow of external foreign matter is high and prevents leakage of the working fluid when the working fluid pressure is high do. In addition, since the lubricant and the working fluid are separated and operated as a separate space through a pair of sealing members, a dedicated lubricant separate from the working fluid can be applied. Therefore, the lubricating performance of the friction portion between the piston rod 110 and the silicone tube 120 can be further improved.

4 is a longitudinal sectional view of the hydrostatic bearing 150 according to the second embodiment of the present invention. As shown, the pockets 152a are not formed as a closed curve along the circumferential direction of the hydrostatic bearing 150, and a plurality of the pockets 152a may be spaced apart in the circumferential direction. Preferably, they may be spaced equidistantly, and three may be arranged radially as shown in Fig. 4A, or six may be arranged radially as shown in Fig. 4B. It is apparent that the number of the pockets 152a can be increased or decreased depending on the use conditions of the servo actuator.

When the pocket 152a is formed in a closed curve along the circumferential direction of the hydrostatic bearing 150, the lubricant can be excessively applied between the rod 111 and the hydrostatic bearing 150, so that the sealing force of the sealing member So that the oil film can be formed more quickly and smoothly on the rod 111 through an appropriate amount of lubricant.

The pockets 152 are formed along the longitudinal direction of the rod 111 and are not formed parallel to the longitudinal direction of the rod 111 but are formed in the circumferential direction It can be formed to be inclined at an angle. That is, the pockets 152 may be formed in a spiral shape along the longitudinal direction of the rod 111. In the case of the helical pocket having the above configuration, a swirl is formed while the lubricant is supplied along the helical pocket during the supply of the lubricant from the lubricant supply means (not shown), so that the oil film can be formed on the outer surface of the rod 111 more quickly There is an advantage.

5 shows the cross-sectional shapes of the pockets 152-1, 152-2, 152-3 and 152-4 according to various embodiments of the present invention, and commonly the pockets 152 are formed by the hydrostatic bearings 150, The width may be narrowed toward the outer side from the inner circumferential surface.

5A shows a basic pocket 152-1 having a "C" cross section. FIG. 5B shows a tapered pocket 152-2 having a narrower width from the inner circumferential surface of the hydrostatic bearing 150 toward the outer side, Respectively.

5C shows a semicircular pocket 152-3 having a semicircular cross section, and FIG. 5D shows a triangular pocket 152-4 having a triangular cross section. The pockets 152 having various shapes can be appropriately selected and applied according to the leakage amount of the lubricant or the degree of reduction of the frictional force.

The technical idea should not be construed as being limited to the above-described embodiment of the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Accordingly, such modifications and changes are within the scope of protection of the present invention as long as it is obvious to those skilled in the art.

100: Servo actuator
110: piston rod 111: rod
112: piston 115: piston pocket
120: cylinder tube 121: piston space
150: Hydrostatic bearing 151: Insertion part
152: pocket O: sealing member

Claims (8)

1. A hydrostatic servo actuator including a cylinder tube and a piston rod having one side inserted into the cylinder tube and linearly reciprocating by hydraulic pressure,
The servo actuator includes:
An annular hydrostatic bearing provided on the other side of the cylinder tube and having an outer circumferential surface coupled to an inner circumferential surface of the cylinder tube and an inner circumferential surface abutting against an outer circumferential surface of the piston rod; / RTI >
The hydrostatic bearing may include:
A pocket formed outwardly from the inner circumferential surface so as to be supplied with the lubricant; , ≪ / RTI >
The working fluid flowing into the cylinder tube and the lubricating oil flowing into the inside of the hydrostatic bearing are separated,
A first insertion portion spaced a predetermined distance from the other side of the pocket and formed to be depressed outwardly from an inner peripheral surface;
A second inserting portion spaced apart from the one side of the pocket by a predetermined distance, the second inserting portion being recessed outward from the inner circumferential surface;
A first sealing member inserted into the first insertion portion; And
A second sealing member inserted into the second insertion portion;
And the hydrostatic servo actuator.
delete delete The method according to claim 1,
The pocket
Wherein a plurality of the piston rods are spaced apart from each other along the longitudinal direction of the piston rod.
5. The method of claim 4,
The pocket
Wherein a plurality of the hydrostatic servo actuators are spaced apart from each other along the circumferential direction of the hydrostatic bearing.
The method according to claim 1,
The pocket
And the width of the hydraulic actuator is narrowed toward the outer side from the inner peripheral surface of the hydrostatic bearing.
The method according to claim 1,
The pocket
And is formed in a spiral shape along the longitudinal direction of the piston rod.
The method according to claim 1,
The piston rod
A piston accommodated in the cylinder tube and formed at one side thereof; And
A rod having one side connected to the piston and the other side exposed to the outside of the cylinder tube; Lt; / RTI >
A piston pocket recessed inwardly on an outer circumferential surface of the piston; The hydrostatic servo actuator is formed.
KR1020150038120A 2015-03-19 2015-03-19 Hydrostatic Servo Actuator KR101598330B1 (en)

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KR1020150038120A KR101598330B1 (en) 2015-03-19 2015-03-19 Hydrostatic Servo Actuator

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210085633A (en) * 2019-12-31 2021-07-08 경성시험기주식회사 Actuator for generating the high-speed vibration
CN113790191A (en) * 2021-10-29 2021-12-14 江苏军宏机械有限公司 High-frequency oil cylinder

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100454659B1 (en) * 1996-01-30 2005-08-09 페데랄-모굴 비스바덴 게엠베하 운트 코. 카게 Sliding bearing element with lubricant pockets
KR20070121878A (en) * 2006-06-23 2007-12-28 주식회사 에스.오.비 Sliding bearing with oil pocket
JP2013534584A (en) * 2010-06-15 2013-09-05 スネクマ Guide / seal device for a turbine engine having a carbon gasket and an integral smooth bearing

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100454659B1 (en) * 1996-01-30 2005-08-09 페데랄-모굴 비스바덴 게엠베하 운트 코. 카게 Sliding bearing element with lubricant pockets
KR20070121878A (en) * 2006-06-23 2007-12-28 주식회사 에스.오.비 Sliding bearing with oil pocket
JP2013534584A (en) * 2010-06-15 2013-09-05 スネクマ Guide / seal device for a turbine engine having a carbon gasket and an integral smooth bearing

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20210085633A (en) * 2019-12-31 2021-07-08 경성시험기주식회사 Actuator for generating the high-speed vibration
KR102315673B1 (en) * 2019-12-31 2021-10-22 경성시험기주식회사 Actuator for generating the high-speed vibration
CN113790191A (en) * 2021-10-29 2021-12-14 江苏军宏机械有限公司 High-frequency oil cylinder

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