WO2017023114A1

WO2017023114A1 - Integrated hydraulic linear actuator

Info

Publication number: WO2017023114A1
Application number: PCT/KR2016/008563
Authority: WO
Inventors: 류성무; 안기탁; 이규영
Original assignee: (주)케이엔알시스템
Priority date: 2015-08-03
Filing date: 2016-08-03
Publication date: 2017-02-09

Abstract

The present invention relates to an integrated hydraulic linear actuator comprising: a housing including a cylinder unit having a chamber formed therein, and a servo valve block forming a part of a servo valve; a piston rod including a piston head provided to reciprocate inside the cylinder unit; a servo valve stage connected to the servo valve block so as to form the servo valve; a sensor unit including a pressure sensor and a displacement sensor; and a control unit connected to the sensor unit and controlling the servo valve. The integrated hydraulic linear actuator according to the present invention can ensure controlled stiffness since a part of the servo valve is provided to be integrated with the housing and an inner flow path formed inside the housing is provided, and thus a separate hydraulic hose is unnecessary, and can also minimize interference of various wires so as to increase the freedom of design since the sensor unit, the valve and the control unit are provided adjacent to each other.

Description

Integral Hydraulic Linear Actuator

The present invention relates to an integrated hydraulic linear actuator, and more particularly to an integrated hydraulic linear actuator comprising a valve, a sensor and a control.

The hydraulic actuator is a component that finally receives motion by applying hydraulic pressure among hydraulic device elements. The linear actuator is provided with a housing and a piston provided inside the housing, the hydraulic pressure is applied to both directions of the piston can be a linear reciprocating motion.

At this time, the hydraulic pressure is supplied to the chamber inside the housing in a pressurized state from the hydraulic pump, and the tube from the pump to the actuator is used to transfer the fluid. However, the existing actuator transfers the fluid through a hose or tube, so when the hydraulic pressure is applied, it can expand by its elasticity and affect the control stiffness. In addition, the control unit, various sensors, etc. are provided separately, there is a problem that can be limited in the design because the conducting wires connecting them may interfere with the movement.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic linear actuator in which a control unit, a sensor unit, and a valve are integrally provided so as to solve the problems of the conventional hydraulic linear actuator.

As a means for solving the above problems, a piston rod comprising a housing including a cylinder portion having a chamber formed therein and a servovalve block forming a part of a servovalve, a piston head configured to reciprocate in the cylinder portion, and a servovalve block. An integrated hydraulic linear actuator may be provided, which is connected to and connected to a sensor unit including a servo valve stage, a pressure sensor, and a displacement sensor, and a sensor unit to control the servo valve.

Here, the housing may be composed of a single member.

In addition, one side of the servovalve block is provided with an input port and an output port for the inlet and out of the hydraulic oil, the cylinder portion may be configured to include a cylinder internal passage formed from the servovalve block to the chamber to supply the hydraulic oil to the chamber therein. .

In addition, the inner wall of the servo valve block and the outer wall of the pipe of the inner channel of the cylinder may be made of a rigid material.

On the other hand, the chamber is divided into a first chamber and a second chamber by a piston head, the inner cylinder flow path is formed of a first cylinder internal flow path connecting the first chamber from the servovalve block and a second chamber connecting the second chamber from the servovalve block. It may be configured to include a two-cylinder internal flow path.

The servovalve block may include a sleeve and a spool of the servovalve, and the servovalve stage may include a flapper and a nozzle.

In addition, the servovalve block may further include a nozzle connection flow path formed in fluid communication with the input port to allow the nozzle to receive hydraulic pressure from the servovalve block and formed on the servovalve stage side.

At this time, the servovalve block is configured at one end of the cylinder in the longitudinal direction, the piston rod may be provided through the other side of the cylinder.

And a connecting surface is provided at the longitudinal end of the servovalve block, the input port and the output port is formed on the connecting surface, the servovalve stage may be coupled to the servovalve block in the thickness direction.

The servovalve block may include a filter and a sleeve and a spool inserted in the width direction of the servovalve block to filter hydraulic oil flowing from an input port.

At this time, the pressure sensor is a first pressure sensor unit and a second pressure sensor in fluid communication with the first cylinder inner passage and the second cylinder inner passage so as to measure the pressure of the hydraulic oil acting on the first chamber and the second chamber, respectively. It may comprise a unit.

The first pressure sensor unit, the second pressure sensor unit, and the servovalve stage may be positioned in the thickness direction of the housing so that a portion protruding to the outside of the housing is minimized.

On the other hand, the displacement sensor may be provided in the lower end cap (LOWER END CAP) to which the piston rod is inserted and slide so as to measure the relative displacement of the piston rod and the housing.

In addition, the control unit may be provided in parallel with the servovalve and the pressure sensor in the thickness direction of the housing so as to minimize the distance connected to the servovalve, the pressure sensor and the displacement sensor, respectively.

Furthermore, it is configured to surround the servovalve, the pressure sensor, and the controller from the outside, and may further include a cover connected to the housing.

At this time, the cover, the connector insertion hole may be formed so that the connector for electrically connecting the control unit and the external electronic device can be inserted.

The housing may be formed by 3D printing such that the first cylinder inner passage and the second cylinder inner passage may be configured as a passage including a bent portion.

In the integrated hydraulic linear actuator according to the present invention, a part of the servovalve is integrally formed with the housing, and an internal flow path formed inside the housing is provided so that a separate hydraulic hose is not required, thereby ensuring control rigidity. In addition, the sensor unit, the valve and the control unit are installed adjacent to each other to minimize the interference of the various wiring has the effect of increasing the design freedom.

1 is a perspective view of an integrated hydraulic linear actuator which is an embodiment according to the present invention.

2 is another perspective view of the embodiment.

3 is an exploded perspective view of the embodiment.

4 is a perspective view of the housing.

5 is an enlarged perspective view showing an enlarged servo valve block.

6 is a cross-sectional view of the servovalve block.

7 is a diagram illustrating an internal flow path.

8 is a view showing another internal flow path.

Hereinafter, an integrated hydraulic linear actuator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. And the names of each component in the description of the following embodiments may be called other names in the art. However, if their functional similarity and identity, even if the modified embodiment can be seen as an equivalent configuration. In addition, the symbols added to each component is described for convenience of description. However, the contents shown in the drawings in which these symbols are described do not limit each component to the ranges in the drawings. Similarly, even if an embodiment in which the configuration on the drawings is partially modified is employed, it can be regarded as an equivalent configuration if there is functional similarity and identity. In addition, in view of the general level of those skilled in the art, if it is recognized as a component to be included naturally, the description thereof will be omitted.

Hereinafter, a direction in which the piston rod 210 of the actuator shown in FIG. 1 reciprocates will be described as a 'length direction', a vertical direction as a 'thickness direction', and a direction perpendicular to the longitudinal direction and a thickness direction as a 'width direction'.

1 is a perspective view of an integrated hydraulic linear actuator which is an embodiment according to the present invention, FIG. 2 is another perspective view of the embodiment, FIG. 3 is an exploded perspective view of the embodiment, and FIG. 4 is a perspective view showing the housing 100.

As shown, the integrated hydraulic linear actuator according to the present invention includes a housing 100, a housing fastening part (not shown), a piston rod 210, a piston rod 210 fastening part, a servo valve stage 400, a sensor part, The controller 600 and the cover 900 may be configured to be included.

The housing 100 forms the overall appearance of the actuator. The housing 100 includes a cylinder unit 130 in which an inner cylindrical space is formed, a servovalve block 150, a control unit installation unit 120, a pressure sensor installation unit 110, and a housing 100 fastening unit. Can be. The cylinder portion 130 has a cylindrical space formed on the inner wall, the inner space may be divided into the first chamber 710 and the second chamber 720 when the piston head 200 is inserted. One end of the cylinder portion 130 is formed with an opening in one end in the longitudinal direction, the piston rod 210 is configured to be inserted into the housing 100 through the opening, the other end is configured as a closed end. After the piston rod 210 is inserted, the lower end cap 300 (LOWER END CAP) is fastened to seal the space between the piston rod 210 and the opening. The inner surface of the lower end cap 300 may be provided with a seal kit in contact with the piston rod 210 to prevent the leakage of hydraulic oil.

The servovalve block 150 is formed on the sealed end side of the cylinder portion 130. The servovalve block 150 constitutes a part of the servovalve and may be combined with a servovalve stage 400 to be described later to perform a function of a servovalve. The thickness of the servovalve block 150 may be formed to be somewhat thinner than the cylinder portion 130 so that the overall appearance of the actuator may be minimized when the servovalve stage 400 to be described later is combined. That is, the thickness when the servovalve stage 400 and the servovalve block 150 are coupled may be configured to be similar to the thickness of other portions of the housing 100.

The servovalve block 150 is composed of a housing 100 and a single member to ensure leakage and rigidity of hydraulic oil. The servovalve block 150 may include a sleeve 154 and a spool 155 of the servovalve, and a filter 156 for filtering hydraulic oil. The servo valve block 150 will be described in detail later with reference to FIGS. 5 and 6.

The controller installation unit 120 provides a space in which the controller 600 is installed. The control unit installation unit 120 is configured to an appropriate thickness so as to minimize the portion protruding in the thickness direction when the control unit 600 is installed. The control unit installation unit 120 may be provided in a flat state on the upper surface of the thickness direction of the housing 100, and is configured in a size suitable for providing the control unit 600 to be described later. The control unit installation unit 120 may be provided between the pressure sensor installation unit 110 and the servovalve.

The cylinder unit 130 may include cylinder

internal flow paths

810 and 820 configured to transfer hydraulic pressure from the servovalve block 150 to the first chamber 710 and the second chamber 720. The

inner cylinder passages

810 and 820 may be configured to be in fluid communication with the chamber through the structure of the cylinder portion 130. The cylinder

internal passages

810 and 820 are the first cylinder internal passage 810 connecting the A port 856 of the servovalve block 150 and the first chamber 710, and the B port of the subvalve block 150 ( 857 and the second cylinder inner channel 820 connecting the second chamber 720 may be configured. The configuration of the cylinder internal flow path will be described in detail later with reference to FIGS. 7 and 8.

The pressure sensor installation unit 110 is formed at one side of the cylinder unit 130. The pressure sensor installation unit 110 is configured to allow the

pressure sensors

501 and 502 to be described later to be inserted, and two pressure sensor installation holes 111 may be provided. Each of the pressure sensor installation holes 111 may be configured to be connected to the first cylinder inner passage 810 and the second cylinder inner passage 820. The pressure sensor installation unit 110 may be configured by placing a step so that the pressure sensor can be inserted in the longitudinal direction. The outer surface of the pressure sensor installation unit 110 may be configured in a suitable thickness and shape so as to form a smooth appearance when the cover 900 to be described later is fastened.

The housing 100 includes a cylinder unit 130, a servovalve block 150, and an internal flow path of the block, a control unit installation unit 120, a pressure sensor installation unit 110, and an internal

cylinder flow path

810, 820. It can be produced using 3D printing. The internal flow path of the servovalve block 150 is complicated, and it is very difficult and sometimes impossible to cut and process. Therefore, the 3D printing may be manufactured to include a complicated flow path inside the servo valve and an internal flow path connected to the inside of the chamber, and in particular, the flow path bent inside the housing 100.

The housing fastening part (not shown) is configured such that the housing 100 can be connected to an external structure. The housing fastening part may be configured at one side of the servovalve block 150. However, this is just an example, it may be made of a variety of configurations capable of fixing the housing 100 to the external structure.

As described above, the piston rod 210 is provided with a piston head 200 at one side thereof and inserted into a cylindrical space of the housing 100. The driving force is generated in the piston head 200 by the pressure difference between the hydraulic oils accommodated in the first chamber 710 and the second chamber 720 and is transmitted to the piston rod 210. The other side of the piston rod 210 may be provided with a piston rod fastening portion (not shown) so as to be connected to the external structure to transmit the driving force.

The servovalve stage 400 is connected to the servovalve block 150 to perform the function of a servovalve. The servovalve stage 400 may be coupled to the servovalve block 150 in the thickness direction. The servovalve stage 400 may include a flapper 401 (FLAPPER), a nozzle 402, a solenoid 403, and the like to drive the spool 155 provided in the servovalve block 150. . The flapper 401 is driven due to the driving of the solenoid 403, and can selectively block the nozzle 402. It is configured to move the spool 155 at a relative pressure difference between the flow paths connected to both nozzles 402.

The servovalve stage 400 may be configured to receive hydraulic pressure from the servovalve block 150. The two nozzles 402 provided in the servovalve stage 400 are in fluid communication with the input port 851, and are in fluid communication with the output port 852 in a space provided with the flapper 401. The servovalve block 150 includes two nozzle connecting passages 855 connecting the sleeve chamber 854 and the respective nozzles 402 so that hydraulic pressure can be supplied to the nozzles 402 of the servovalve stage 400. It may be formed on the balance stage side.

The sensor unit is configured to measure each state of the linear actuator. The sensor unit may include

pressure sensors

501 and 502 and a displacement sensor 550.

The pressure sensor includes a first pressure sensor unit 501 and a second pressure sensor unit 502 to measure the pressure of the hydraulic oil acting on the first chamber 710 and the second chamber 720. The first pressure sensor unit 501 and the second pressure sensor unit 502 may be installed in the two pressure sensor installation holes 111, respectively. At this time, the sealing may be made so that the fluid inside does not leak.

The displacement sensor 550 is configured to prompt the relative position of the piston rod 210 and the housing 100. The displacement sensor 550 may be configured as a LVAR (LINEAR VARIABLE DIFFERENTIAL TRANSFORMER). The displacement sensor 550 may be provided in the lower end cap 300.

The control unit 600 is configured to receive each state value of the actuator from the pressure sensor and the displacement sensor 550 and to control the servovalve. The control unit 600 is parallel to the servovalve, pressure sensor installation unit 110 in a thickness direction on one side of the housing 100 so as to minimize the distance between the pressure sensor, the displacement sensor 550 and the conductor connected to the servovalve. Is located. The controller 600 may control the compliance control (THE COMPLIANCE CONTROL) or the like to be performed in response to an external load acting on the piston rod 210 by measuring the current position of the piston rod 210 and the pressure formed in each chamber. . However, the function of the controller 600 is not limited to the compliance control, and various control methods for controlling the servovalve by feeding back the measured value of each sensor may be applied.

The control unit 600 may include an amplifier. Therefore, signals acquired from various sensors can be smoothly processed. The controller 600 includes a connector for connecting to the outside, and is connected to an external central processing unit and the like to receive a driving command.

The cover 900 may be configured in a shape surrounding the control unit 600, the servo valve, the pressure sensor, and the like provided in the housing 100 to protect them from the outside. At this time, one end of the cover 900 is fastened to the housing 100 in a state facing the pressure sensor installation unit 110, and is configured so that the outer surface together with the housing 100 can be a smooth shape as a whole. The cover 900 is provided with a connector insertion hole 910 so that an external connector can be connected to the connector of the control unit 600.

Hereinafter, the servovalve block 150 will be described in detail with reference to FIGS. 5 and 6. 5 is an enlarged exploded perspective view showing an enlarged and disassembled servo valve block 150, and FIG. 6 is a cross-sectional view of the servo valve block 150.

As illustrated, the servovalve block 150 may have a sleeve hole 152, a filter hole 153, an internal flow path of the block, and a connection surface 151.

The sleeve hole 152 may be formed in the width direction of the servovalve block 150. The sleeve 154 is inserted into the sleeve hole 152, and the spool 155 is inserted into the sleeve 154. Annular sleeve chambers 854 connected to the input ports 851 may be formed at both sides of the sleeve hole 152 in the longitudinal direction. Adjacent to the sleeve chamber 854 may be formed an annular chamber to which the A port 856 and the B port 857 are connected, respectively. Since the sleeve hole 152 is formed in the width direction, the sleeve hole 152 may be symmetrically connected to the first cylinder inner passage 810 and the second cylinder inner passage 820 which are spaced apart in the width direction in the housing 100. The internal flow path is configured to be short to ensure the rigidity of the servovalve block 150.

The filter hole 153 is configured to filter impurities in the hydraulic oil flowing in. The filter hole 153 may be formed in the width direction of the servovalve block 150 in parallel with the sleeve hole 152. A central portion of the filter hole 153 may have a flow passage in fluid communication with the input port 851, and a block internal flow passage connected to the sleeve chamber 854 may be formed at both sides. The hydraulic oil introduced into the central portion of the filter hole 153 may move to both ends of the filter hole through the filter part 156, pass through the internal flow path of the block, and may flow into the sleeve chamber 854.

In the central portion of the sleeve 154, a block internal flow path connected to the output port 852 may be formed.

The connection surface 151 is formed at one end of the servovalve block 150 and may be formed at the end of the longitudinal direction. The connection surface 151 may be provided in parallel with the input port 851 and the output port 852 in the adjacent position. The input port 851 and the output port 852 may be connected to the external hydraulic line, respectively.

The hydraulic oil flow in the servovalve is as follows. The hydraulic oil flows into the input port 851 while the servovalve block 150 is coupled to the servovalve stage 400 and is filtered through the filter unit 156. Then, a part of the hydraulic oil flows into the nozzle 402 of the servovalve stage 400 and the other flows into the sleeve chamber 854. Thereafter, the hydraulic oil introduced into the sleeve chamber 854 flows to the A port 856 or the B port 857 according to the operation of the valve, and selectively flows into each chamber.

Hereinafter, the cylinder internal flow path will be described in detail with reference to FIGS. 7 and 8. 7 and 8 are diagrams illustrating an internal flow path.

As shown, the first cylinder internal passage 810 is formed in fluid communication with the first chamber 710 located on the servovalve side from the servovalve block 150. The first cylinder internal passage 810 is connected to the A port 856 of the servovalve block 150 and includes a plurality of bent portions. The first cylinder inner channel 810 extends a predetermined distance from the A port 856, and a branching point is formed. One flow path is connected to the first chamber 710 after the branch point, and the other flow path extends to the pressure sensor hole so that pressure can be transmitted to the first pressure sensor unit 501. At this time, it extends in the longitudinal direction of the housing 100 and then extends along the circumference of the housing 100 through the bent portion and is connected to the pressure sensor hole.

The second cylinder internal passage 820 is connected to the B port 857 of the servovalve block 150 and extends in the longitudinal direction of the housing 100 to form a branch point. After the branch point, one flow path is in fluid communication with the second chamber 720, and the other flow path is configured to transmit pressure to the second pressure sensor unit 502. In this case, the flow passage extends in the circumferential direction symmetrically with the first cylinder inner flow passage 810 and then extends to the pressure sensor installation hole 111.

On the other hand, the above-described cylinder internal flow path, but the pressure sensor installation hole 111 is an example formed in the lower end cap 300 side, the pressure sensor installation hole 111 may be formed in various positions. The first cylinder internal passage 810 may be modified in various combinations according to the position of the pressure sensor installation hole 111. In this case, even when a complicated flow path is to be formed using 3D printing as described above, a smooth manufacturing is possible.

In the integrated hydraulic linear actuator described above, all of the internal flow paths are made of rigid material. Therefore, it is possible to prevent the occurrence of a control error due to the elasticity of the hose which is a problem that may occur when the hydraulic hose is configured. In addition, the amplifier built-in control unit is provided to facilitate the signal processing of each sensor, can prevent the exposure of the wire connecting each electronic device, and a compact configuration is possible.

In addition, since the servovalve block and the cylinder are composed of a single member housing, the rigidity can be maintained, and a flow path is formed inside the body structure, thereby effectively preventing external leakage.

Claims

A housing including a cylinder part having a chamber formed therein and a servovalve block constituting a part of the servovalve;

A piston rod connected to the piston head configured to reciprocate in the cylinder portion;

A servovalve stage connected to the servovalve block to constitute the servovalve;

A sensor unit including a pressure sensor and a displacement sensor; And

An integrated hydraulic linear actuator is connected to the sensor unit and includes a control unit for controlling the servovalve.
The method of claim 1,

The housing is a unitary hydraulic linear actuator, characterized in that consisting of a single member.
The method of claim 2,

One side of the servo valve block is provided with an input port and an output port for entering and exiting the hydraulic oil,

And the cylinder portion includes an inner cylinder flow passage formed from the servovalve block to the chamber to supply the hydraulic oil to the chamber therein.
The method of claim 3, wherein

The inner wall of the servo valve block and the outer wall of the pipe of the inner channel of the cylinder is an integral hydraulic linear actuator, characterized in that the rigid material.
The method of claim 4, wherein

The chamber is divided into a first chamber and a second chamber by the piston head,

The cylinder internal flow passage includes a first cylinder internal flow passage connecting the first chamber from the servovalve block and a second cylinder internal flow passage connecting the second chamber from the servovalve block.
The method of claim 4, wherein

The servovalve block includes a sleeve and a spool of the servovalve,

The servo valve stage is a one-piece hydraulic linear actuator, characterized in that it comprises a flapper and a nozzle (Nozzle).
The method of claim 6,

The servovalve block,

And a nozzle connection flow path in fluid communication with the input port to allow the nozzle to receive hydraulic pressure from the servovalve block and formed toward the servovalve stage.
The method of claim 6,

The servovalve block is configured at one end in the longitudinal direction of the cylinder portion,

The piston rod is an integral hydraulic linear actuator, characterized in that provided through the other side of the cylinder portion.
The method of claim 8,

The longitudinal end of the servovalve block is provided with a connection surface,

The input port and the output port is formed on the connection surface,

The servo valve stage is integrated hydraulic linear actuator, characterized in that coupled to the servo valve block in the thickness direction.
The method of claim 9,

The servovalve block,

The sleeve and the spool are inserted and installed in the width direction of the servovalve block,

And a filter unit for filtering the hydraulic oil flowing from the input port.
The method of claim 5,

The pressure sensor may include a first pressure sensor unit in fluid communication with the first cylinder inner passage and the second cylinder inner passage, respectively, to measure the pressure of the hydraulic oil acting on the first chamber and the second chamber, respectively. An integrated hydraulic linear actuator, characterized in that it comprises a pressure sensor unit.
The method of claim 11, wherein

The first pressure sensor unit, the second pressure sensor unit and the servo valve stage are integral hydraulic linear actuators, characterized in that located in the thickness direction of the housing to minimize the portion protruding out of the housing.
The method of claim 12,

The displacement sensor is an integrated hydraulic linear actuator, characterized in that provided in the lower end cap (LOWER END CAP) that the piston rod is inserted and slide so as to measure the relative displacement of the piston rod and the housing.
The method of claim 13,

The control unit,

Integral hydraulic linear actuator, characterized in that provided in parallel with the servo valve and the pressure sensor in the thickness direction of the housing so that the distance connected to each of the servo valve, the pressure sensor and the displacement sensor can be minimized.
The method of claim 14,

The servo valve, the pressure sensor and the control unit is configured to surround the integrated hydraulic linear actuator further comprises a cover connected to the housing.
The method of claim 15,

The cover,

An integrated hydraulic linear actuator, characterized in that the connector insertion hole is formed so that the connector for electrically connecting the control unit and the external electronic device is inserted.
The method of claim 5,

And said housing is formed by 3D printing so that said first cylinder inner passage and said second cylinder inner passage can be configured as a passage including a bent portion.