KR101421798B1 - Servo valve apparatus - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve apparatus for controlling the flow of a hydraulic fluid for operating a cylinder for a reel, and a servo valve apparatus according to an embodiment of the present invention is a servo valve for controlling the operation of a hydraulic cylinder, A spool unit in which a plurality of flow paths through which fluids enter and exit are formed, and a spool for interrupting the opening and closing of the flow paths is incorporated; And a driving unit connected to the spool unit and having a flapper for directly moving the spool while being rotated in a horizontal direction with the spool by the application of electricity.

Description

SERVO VALVE APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a servo valve apparatus, and more particularly, to a servo valve apparatus for controlling a flow of hydraulic fluid for operating a cylinder for a reel.

In recent years, various electric-hydraulic servo valves have been developed and used in various power transmission devices such as aircraft, automobile, and crankshaft, truck, and ship using hydraulics as the need for electronic control of flow rate and hydraulic pressure has increased. In the case of a servo valve used for precise position control among such electro-hydraulic servo valves, a nozzle flapper type using an electromagnet is mainly used as the drive vibrator.

Conventionally, the configuration and operation of the electro-hydraulic servo valve composed of the nozzle flapper type are specifically known in "Servo valve with more stable dynamic characteristics (Publication No. 10-2002-0034473) ".

These servo valves are used in various processes in the steel industry, for example in the Strip Center Position Control System, which centers the strip and mandrel in a mandrel drilling machine that coils the strip. do.

FIG. 1 is a view showing a strip center position control system to which a general servo valve is applied, and FIGS. 2a and 2b are views showing an operation state of a general servo valve.

A general strip center position control system includes a motor 450 and a mandrel drill 470 for coiling the strip S while being driven by the motor 450. The motor 450 and the mandrel 470 are interlocked through the reducer 420 and the shaft 460. At this time, the decelerator 420 and the mandrel 470 are moved to the left and right to align the center of the strip S to be coiled. In order to move the reducer 420 and the mandrel 470 left and right, Is mounted on the reducer base 430 via the slide bearing 440 and the speed reducer 420 is slid in the left and right direction by the hydraulic cylinder 300. [

The hydraulic cylinder 300 includes a cylinder body 310 having a head side compartment 310a and a rod side compartment 310b formed therein and a head 320 integrally moving in the cylinder body 310, (330). At this time, the head side compartment 310a and the rod side compartment 310b are partitioned based on the head 320. The rod 330 is connected to the speed reducer 420 through the connecting bar 410 and is connected to the mandrel 470 while the reducer 420 is moved in conjunction with the movement of the head 320 and the rod 330. [ .

The hydraulic pressure supplied to or discharged from the head side compartment 310a and the rod side compartment 310b of the hydraulic cylinder 300 is precisely controlled so that the mandrel 470 is positioned on the reel center line And the movement is controlled within a certain range.

The servo valve is a means for precisely controlling the hydraulic pressures in and out of the head side compartment 310a and the rod side compartment 310b of the hydraulic cylinder 300. In the servo valve, , A spool unit (100) having a spool (120) therein for interrupting the opening and closing of the flow paths; A torque motor unit 200 connected to the spool unit 100 and having a flapper 220 for rotating the spool 120 in a vertical direction by the application of electric power and indirectly moving the spool 120 by hydraulic pressure, .

The spool unit 100 includes a spool housing 110 in which a plurality of flow paths are formed and a spool 120 and a filter 130 provided in the spool housing 110. The spool housing 110 is provided with an inflow passage 113 through which the fluid flows from the hydraulic pump 117, a head side passage 114 connected to the head side compartment 310a of the hydraulic cylinder 300, A rod side oil passage 115 connected to the rod side compartment 310b of the spool housing 110, a discharge passage 116 discharged to the hydraulic tank 118 from inside the spool housing 110, A first nozzle flow path 111 and a second nozzle flow path 112 connected to the first nozzle 250a and the second nozzle 250b formed on both sides of the flapper 220 are formed.

The filter 130 is installed in the inflow channel 113.

The torque motor unit 200 includes a torque motor housing 210 in which the flapper 220 is installed, a coil 230 surrounding both sides of the upper end of the flapper 220, And the electromagnet 240 disposed between the first nozzle 250a and the second nozzle 250. The torque motor housing 210 includes the first nozzle 250a and the second nozzle 250a so as to be opposed to each other with the lower end of the flapper 220 interposed therebetween, (250b) are formed.

The operation state of a general servo valve constructed as described above will be described with reference to the drawings.

1, a control current is not applied to the coil 230 when the head 320 and the rod 330 of the hydraulic cylinder 300 are stopped. At this time, The fluid is uniformly branched into the first nozzle 250a and the second nozzle 250b through the first nozzle flow path 111 and the second nozzle flow path 112 while the impurities are removed while passing through the filter 130 The fluid is uniformly sprayed from the first nozzle 250a and the second nozzle 250b, and the flapper 220 is maintained in a state in which the flapper 220 is not rotated clockwise or counterclockwise. At this time, the head side oil passage 114, the rod side oil passage 115 and the discharge passage 116 are kept closed by the spool 120.

In this state, in order to move the head 320 and the rod 330 of the hydraulic cylinder 300 toward the head side compartment 310a as required, a control current is applied to the coil 230 as shown in FIG. 2A The flapper 220 is rotated in the clockwise direction. The first nozzle 250a is closed by the lower area of the flapper 220 to increase the pressure of the fluid supplied to the first nozzle flow path 111 and the fluid supplied to the second nozzle flow path 112 flows 2 nozzle 250b, the pressure is maintained relatively lower than that of the first nozzle flow path 111. In this case, As the pressure difference between the first nozzle flow path 111 and the second nozzle flow path 112 is generated as described above, the spools, which are supported at both ends by the fluid in the first nozzle flow path 111 and the second nozzle flow path 112, The flow path of the fluid flows from the left side to the right side so that the inflow passage 113 and the rod side passage 115 are communicated with each other and the fluid flows into the rod side passage 115. The head side passage 114 and the discharge passage And the fluid in the head side flow path 114 is discharged to the hydraulic pressure tank 118 through the discharge flow path 116. The head 320 of the hydraulic cylinder 300 and the rod 330 are controlled to be moved toward the head 320 side.

Conversely, contrary to FIG. 2A, in order to move the head 320 and the rod 330 of the hydraulic cylinder 300 toward the rod-side compartment 310b, a control current is applied to the coil 230 as shown in FIG. 2B The flapper 220 is rotated in the counterclockwise direction. The second nozzle 250b is closed by the lower region of the flapper 220 so that the pressure of the fluid supplied to the second nozzle flow path 112 is increased and the fluid supplied to the first nozzle flow path 111 is supplied 1 nozzle 250a, the pressure is relatively lower than that of the second nozzle flow path 112. As shown in FIG. As the pressure difference between the first nozzle flow path 111 and the second nozzle flow path 112 is generated as described above, the spools, which are supported at both ends by the fluid in the first nozzle flow path 111 and the second nozzle flow path 112, The fluid flows from the right side to the left side so that the inflow channel 113 and the head side channel 114 communicate with each other and the fluid flows into the head side channel 114. The rod side channel 115 and the discharge channel And the fluid in the rod side flow path 115 is discharged to the hydraulic tank 118 through the discharge flow path 116. [ The head 320 of the hydraulic cylinder 300 and the rod 330 are controlled to be moved toward the rod 330 side.

However, since the above-described general servo valve uses a high-pressure fluid, the filter 130 is often clogged or broken, and the first nozzle 250a and the second nozzle 250b having a diameter of about 0.5 mm The first nozzle 250a and the second nozzle 250b directly charge the flapper 220 to cause the outer surface of the flapper 220 to be worn or damaged This frequently occurs and accidents that the servo valve is not operated precisely frequently occur.

In addition, when the fluid in the head side compartment 310a or the rod side compartment 310b of the hydraulic cylinder 300 is instantaneously discharged through the discharge flow path 116, the fluid flows from the sealed state to the open state instantaneously The instantaneous vibration is generated while the spool 120 is moved in the direction in which the discharge flow path 116 is opened so as to prevent precise movement of the spool 120, There is a problem that the position control of the motor is unstable.

Publication No. 10-2002-0034473 (May 05, 2002)

The present invention provides a servo valve device capable of suppressing the occurrence of a failure by simplifying the structure by implementing a direct drive method of a spool for controlling a flow of a fluid for operating a hydraulic cylinder by a flapper do.

The present invention also provides a servo valve device capable of moving the spool in a straight-ahead manner so that the movement of the spool is stably operated, thereby improving the control accuracy of the hydraulic cylinder.

A servo valve apparatus according to an embodiment of the present invention is a servo valve for controlling the operation of a hydraulic cylinder. The servo valve includes a plurality of flow paths for fluid entering and flowing therein, a spool unit including a spool for interrupting opening and closing of the flow paths, ; And a driving unit connected to the spool unit and having a flapper for directly moving the spool while being rotated in a horizontal direction with the spool by the application of electricity.

An insertion slot is formed on a central upper surface of the spool so as to be orthogonal to a longitudinal direction of the spool on a horizontal plane, the flapper being installed in a lateral direction; An operating bar extending from a central lower surface of the armature so as to be orthogonal to a longitudinal direction of the armature on a vertical plane; And an eccentric protrusion which is eccentric at the lower end of the operation bar and eccentric from a horizontal center of the operation bar, the eccentric protrusion being disposed to be inserted into the insertion slot of the spool.

Wherein the driving unit comprises: a flapper housing in which the flapper is embedded; A pair of coils each surrounding both side regions of the armature constituting the flapper; And a plurality of electromagnets disposed laterally apart from both side ends of the armature constituting the flapper, wherein the flapper moves the electromagnet in a direction having a polarity selected from the electromagnets by a current applied to the coil And the eccentric projection is rotated in a clockwise or counterclockwise direction on a horizontal plane in conjunction with the rotation of the electromagnetic to move the spool in the horizontal direction on the horizontal plane.

The electromagnets are characterized in that a pair of electromagnets having mutually different polarities are disposed on the horizontal plane so as to be spaced apart from each other with the end portions of both sides of the armature of the flapper interposed therebetween.

Wherein the spool unit further includes a spool housing having a receiving space formed therein so that the spool is embedded therein so as to be moved in a lateral direction and the plurality of flow paths are spaced apart from each other to communicate with the receiving space, A flow path formed in the spool housing includes a head side flow path and a rod side flow path communicating with the head side compartment and the rod side compartment of the hydraulic cylinder, respectively; A discharge flow path disposed between the head side flow path and the rod side flow path and discharging fluid; And a first inflow passage and a second inflow passage which are respectively disposed outside the head-side passage and the rod-side passage and into which the fluid flows.

And a relief valve for compensating a minimum flow rate of the fluid flowing in the discharge passage.

According to the embodiment of the present invention, a spool which is directly operated by the rotation of the flapper is implemented without actuating the spool in the nozzle flapper type as in the conventional art, thereby realizing a sub-valve having a simple structure. Accordingly, it is possible to control the sub-valve easily and control the hydraulic pressure with high accuracy.

By providing a relief valve on the discharge flow path to preserve the minimum flow rate of the fluid flowing on the discharge flow path, it is possible to prevent the spool from malfunctioning like the vibration of the spool, thereby precisely controlling the hydraulic cylinder. There is an effect that quality can be improved.

1 is a view showing a strip center position control system to which a general servo valve is applied,
FIGS. 2A and 2B are views showing an operating state of a general servo valve,
3 is a view showing a strip center position control system to which a servo valve device according to an embodiment of the present invention is applied,
4A and 4B are views for explaining the operation principle of a spool according to an embodiment of the present invention,
FIGS. 5A and 5B are views showing an operating state of a servo valve apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Wherein like reference numerals refer to like elements throughout.

FIG. 3 is a view showing a strip center position control system to which a servo valve apparatus according to an embodiment of the present invention is applied. FIGS. 4A and 4B are views for explaining the operation principle of a spool according to an embodiment of the present invention, FIGS. 5A and 5B are views showing an operating state of a servo valve apparatus according to an embodiment of the present invention.

First, a servo valve apparatus according to an embodiment of the present invention is a type of electro-hydraulic servo valve, and may be applied to various fields that require control of operation of a hydraulic cylinder.

In the present embodiment, a servo valve device in which a servo valve device is applied to a strip center position control system will be described as an example of a preferred embodiment of the present invention. The structure of the strip center position control system has been described above, but the structure of the servo valve apparatus according to an embodiment of the present invention will be described once again.

The strip center position control system includes a motor and a mandrel drill 470 for coiling the strip S while being rotated by driving of the motor 450. The motor 450 and the mandrel 470 are connected to a speed reducer (420) and the shaft (460). At this time, the decelerator 420 and the mandrel 470 are moved to the left and right to align the center of the strip S to be coiled. In order to move the reducer 420 and the mandrel 470 left and right, Is mounted on the reducer base 430 via the slide bearing 440 and the speed reducer 420 is slid in the left and right direction by the hydraulic cylinder 300. [

The hydraulic cylinder 300 includes a cylinder body 310 having a head side compartment 310a and a rod side compartment 310b formed therein and a head 320 integrally moving in the cylinder body 310, (330). At this time, the head side compartment 310a and the rod side compartment 310b are partitioned based on the head 320. The rod 330 is connected to the speed reducer 420 through the connecting bar 410 and is connected to the mandrel 470 while the reducer 420 is moved in conjunction with the movement of the head 320 and the rod 330. [ .

The hydraulic pressure supplied to or discharged from the head side compartment 310a and the rod side compartment 310b of the hydraulic cylinder 300 is precisely controlled so that the mandrel 470 is positioned on the reel center line And the movement is controlled within a certain range.

The servo valve apparatus according to an embodiment of the present invention includes a spool unit 500 having a spool 520 and a drive unit 600 for operating the spool 520.

The spool unit 500 is a unit for controlling the operation of the hydraulic cylinder 300 by using the flow of hydraulic pressure and includes a spool housing 510 in which a plurality of fluid passages are formed, And a spool 520 for controlling opening and closing of the flow channels while being moved inside.

The spool housing 510 is a case in which the spool 520 is housed. The spool 520 is accommodated in the spool housing 510 to accommodate the spool 520 to move in the lateral direction. And is formed to be communicated with the accommodation space.

A plurality of flow paths formed in the spool housing 510 include a head side flow path 523 communicating with the head side compartment 310a of the hydraulic cylinder 300; A rod-side passage 524 communicating with the rod-side compartment 310b of the hydraulic cylinder 300; A discharge passage 525 disposed between the head-side passage 523 and the rod-side passage 524 to discharge the fluid; Side flow path 523 and the rod-side flow path 524, and is a first inflow path 522a and a second inflow path 522b through which fluid flows.

At this time, the first inflow passage 522a and the second inflow passage 522b are joined to a hydraulic pump 526 which forms an inflow passage 522 and provides a fluid.

The discharge passage 525 is connected to a hydraulic tank 527 through which a fluid is discharged. A relief valve 528 is provided on the discharge passage 525 to compensate for a minimum flow rate of the fluid flowing through the discharge passage 525. As the minimum flow rate is maintained in the discharge passage 525 by the relief valve 528, the fluid is suddenly discharged into the hydraulic tank 527 in the discharge passage 525, and the flow rate is abruptly changed And prevents the fluid from flowing backward from the hydraulic tank 527 side. Accordingly, it is possible to prevent the spool 520 from being unstably operated by the fluid flowing in the discharge passage 525.

The spool 520 is embedded in the spool housing 510 and is moved in the lateral direction (right and left directions in FIG. 3).

4B, the insertion slot 521 is formed on the central upper surface so that the spool 520 is orthogonal to the longitudinal direction of the spool 520 on a horizontal plane. Thus, the flapper 620, which will be described later, is inserted into the insertion slot 521 and engaged, and the spool 520 is directly moved in conjunction with the rotation of the flapper 620.

The drive unit 600 is a unit for directly moving the spool 520 and is connected to the upper portion of the spool housing 510 and rotates horizontally with the spool 520 by the application of electricity. And a flapper 620 for moving the spool 520 directly.

The flapper 620 is formed in a substantially "T" shape as shown in FIG. 4A, and includes an armature 621 installed laterally; An operating bar 622 extending perpendicular to the longitudinal direction of the armature 621 at a central lower surface of the armature 621; And an eccentric protrusion 623 which is eccentric at the lower end of the actuating bar 622 and extends downward from the center of the actuating bar 622 in the horizontal plane.

In addition, the driving unit 600 includes a flapper housing 610 in which the flapper 620 is embedded; A pair of coils 630 surrounding both side regions of the armature 621 constituting the flapper 620; And further includes a plurality of electromagnets 640 disposed laterally spaced from both ends of the armature 621 constituting the flapper 620.

The flapper housing 610 is a case in which the flapper 620, the coil 630, and a plurality of electromagnets 640 are embedded.

The coil 630 applies a control current to generate a magnetic force between the electromagnets 640, thereby providing a force to rotate the flapper 620.

The electromagnet 640 is disposed such that a pair of electromagnets having different polarities are spaced apart from each other on a horizontal plane with an end portion of each side of the armature 621 of the flapper 620 interposed therebetween.

The flapper 620 is rotated on a horizontal plane while the armature 621 is moved in a direction having a selected polarity among the electromagnets 640 by a current applied to the coil 630, The eccentric projections 623 are rotated clockwise or counterclockwise on the horizontal plane in conjunction with the rotation.

The eccentric protrusion 623 is rotated clockwise or counterclockwise on the horizontal plane to move the spool 520 in the horizontal direction on the horizontal plane.

The lateral movement of the spool 520 interlocked with the horizontal plane rotation of the flapper 620 will be described with reference to FIG.

4A is a view showing a state in which the spool 520 maintains the neutral position. When the control current is not applied to the coil 630, the flapper 620 is connected to the center of the pair of electromagnets 640, The state of being placed in the position is maintained. At this time, the state in which the eccentric protrusion 623 of the flapper 620 is disposed above the insertion slot 521 of the spool 520 is maintained.

The spool 520 does not move in a state where the spool 520 maintains the neutral position as shown in FIG. When the control current having the magnitude and polarity set in the coil 630 is applied in this state, any one of the electromagnets 640, for example, the electromagnet 640 on the left side as shown in FIG. 4B, The flapper 620 is rotated clockwise on the horizontal plane. The eccentric protrusion 623 moves clockwise by about 90 degrees and the eccentric protrusion 623 pushes the inner wall surface of the insertion slot 521 to the left to move the spool 520 to the left.

4B, when a control current having a polarity different from that of the control current applied to the coil 630 is applied, the electromagnet 640 on the right side of the electromagnet 640, as shown in FIG. 4B, The flapper 620 is rotated counterclockwise on the horizontal plane as the armature 621 moves. Then, the eccentric protrusion 623 moves counterclockwise by about 90 degrees. With this movement, the eccentric protrusion 623 pushes the inner wall surface of the insertion slot 521 to the right to move the spool 520 to the left.

The operating state of the servo valve apparatus according to an embodiment of the present invention will be described with reference to the drawings.

3, when the head 320 and the rod 330 of the hydraulic cylinder 300 are stopped, no control current is applied to the coil 630, The fluid does not flow into the head side flow path 523 and the rod side flow path 524 due to the intermittent movement of the spool 520 and thus the head 320 and the rod 330 of the hydraulic cylinder 300 are stopped maintain.

5A, in order to move the head 320 and the rod 330 of the hydraulic cylinder 300 toward the head side compartment 310a, the control current The spool 520 is directly moved to the left by the eccentric protrusion 623 of the flapper 620 while the flapper 620 is rotated in the counterclockwise direction on the horizontal plane The fluid supplied from the hydraulic pump 526 flows into the rod compartment 310b so that the head 320 and the rod 330 are connected to the head side compartment 310a. As the spool 520 is moved to the left side, the head side passage 523 and the discharge passage 525 are communicated with each other and the head 320 is moved toward the head side compartment 310a, And the discharged fluid is discharged to the hydraulic tank 527 through the head side oil passage 523 and the discharge oil passage 525 in order.

5A, in order to move the head 320 and the rod 330 of the hydraulic cylinder 300 toward the rod-side compartment 310b, a control current is applied to the coil 630 as shown in FIG. 5B The spool 520 is rotated to the right by the eccentric protrusion 623 of the flapper 620 to rotate the flapper 620 clockwise on the horizontal plane The fluid supplied from the hydraulic pump 526 flows into the head side compartment 310a while the inlet flow path 522a and the head side flow path 523 are communicated with each other so that the head 320 and the rod 330 are connected to the rod side compartment 310b, Direction. As the spool 520 is moved to the right side, the rod side passage 524 and the discharge passage 525 are communicated with each other and the head 320 is moved toward the rod side compartment 310b, thereby filling the rod side compartment 310b The fluid is discharged to the hydraulic tank 527 through the rod-side passage 524 and the discharge passage 525 in order.

5A and 5B, the fluid discharged to the hydraulic tank 527 through the discharge passage 525 is kept at a minimum flow rate by the relief valve 528 so that the vibration of the spool 520 It is possible to prevent the spool 520 from being slightly malfunctioned.

Although the present invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the present invention is not limited thereto but is limited by the following claims. Accordingly, those skilled in the art will appreciate that various modifications and changes may be made thereto without departing from the spirit of the following claims.

300: hydraulic cylinder 310: cylinder body
310a: head side compartment 310b: rod side compartment
320: head 330: rod
410: connecting bar 420: reducer
430: Reducer base 440: Slide bearing
450: motor 460: shaft
470: Men Drill S: Strip
500: spool unit 510: spool housing
520: spool 521: insertion slot
522: Inflow channel 522a: First inflow channel
522b: second inflow channel 523: head side channel
524: Rod-side flow path 525:
526: Hydraulic pump 527: Hydraulic tank
528: relief valve 600: drive unit
610: flapper housing 620: flapper
621: Armature 622: Operational bar
623: eccentric projection 630: coil
640: electromagnet

Claims (6)

A servo valve for controlling the operation of a hydraulic cylinder,
A spool unit in which a plurality of flow paths through which fluids enter and exit are formed, and a spool for interrupting the opening and closing of the flow paths is incorporated;
And a driving unit connected to the spool unit and having a flapper for directly moving the spool while being rotated on a horizontal plane with the spool by the application of electricity,
The flapper comprising: an armature installed in a lateral direction; An operating bar extending from a central lower surface of the armature so as to be orthogonal to a longitudinal direction of the armature on a vertical plane; And an eccentric projection which is eccentric from a horizontal center of the operation bar and extends downward at a lower end of the operation bar,
Wherein an insertion slot is formed in a central upper surface of the spool so as to be longer than a diameter of the eccentric projection so as to be perpendicular to a longitudinal direction of the spool on a horizontal plane,
Wherein the eccentric protrusion is disposed to be inserted into the insertion slot of the spool and is moved inside the insertion slot.
delete The method according to claim 1,
Wherein the driving unit comprises: a flapper housing in which the flapper is embedded; A pair of coils each surrounding both side regions of the armature constituting the flapper; And a plurality of electromagnets disposed laterally apart from both side ends of the armature constituting the flapper,
Wherein the flapper is rotated on a horizontal plane while the electromagnetic is moving in a direction having a polarity selected from the electromagnets by a current applied to the coil, and the eccentric projections are rotated clockwise or counterclockwise So as to move the spool in the horizontal direction on the horizontal plane.
The method of claim 3,
Wherein the electromagnets are disposed such that a pair of electromagnets having mutually different polarities are spaced from each other on a horizontal plane with an end portion of each armature on both sides of the armature being interposed therebetween.
The method according to claim 1,
Wherein the spool unit further includes a spool housing having a receiving space formed therein to allow the spool to move in a lateral direction and to communicate with the receiving space through a lower surface of the spool unit,
The flow path formed in the spool housing
A head-side flow path and a rod-side flow path communicating with the head side compartment and the rod side compartment of the hydraulic cylinder, respectively;
A discharge flow path disposed between the head side flow path and the rod side flow path and discharging fluid;
And a first inflow passage and a second inflow passage which are respectively disposed outside the head-side passage and the rod-side passage and into which the fluid flows.
The method of claim 5,
Wherein a relief valve is provided to compensate a minimum flow rate of a fluid flowing into the discharge passage.

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