KR20190028175A - automatic volumetric flow compensation valve for electro hydrostatic actuator - Google Patents

Abstract

The present invention relates to an electrohydraulic hybrid actuator automatic compensation valve which is capable of automatically compensating for a difference in volume flow generated during input and output of a hydraulic cylinder and solving problems caused by a change in performance depending on the length of a push bar and leakage in a neutral state, thereby improving the responsiveness and productivity. An electrohydraulic hybrid actuator automatic compensation valve, which controls a direction of a working oil flow between both sides of a hydraulic cylinder in accordance with a working oil delivery direction of a bidirectional hydraulic pump such that a difference in flow rate between both sides of the hydraulic cylinder partitioned by a piston is compensated, includes a compensating passage connected to a storage tank; a connecting passage extending from both ends of the compensating passage to both sides; a compensation valve block in which oil passages and opening/closing flow passages are formed symmetrically with respect to each other on the outer side and the inner side of both ends of the connecting passage so that hydraulic oil supplied to and discharged from one side and the opposite side of the hydraulic cylinder flows; and a double poppet provided symmetrically on each of the connection passages in a pair so as to be pressurized by the pressure of the hydraulic fluid flowing into the metering passage, and including an outer circumferential portion selectively opening and closing the opening and closing passage and having a slide groove formed therein, and an inner circumferential portion slidably moved in the slide groove portion by a pressure applied to the outer side water pressure area and in which a push bar is connected to the inner side portions.

Description

An automatic flow compensation valve for an electrohydraulic hybrid actuator,

The present invention relates to an automatic flow compensation valve of an electrohydraulic hybrid actuator, and more particularly, to an automatic flow compensation valve of an electrohydraulic hybrid actuator, which is capable of automatically compensating for a difference in volume flow generated during input / output of a hydraulic cylinder, And more particularly, to an automatic flow compensation valve of an electrohydraulic hybrid actuator having improved responsiveness and productivity in low speed and high speed regions.

In general, the single-rod hydraulic cylinder is widely applied as an operating part of a molding machine and a machine, which require a large thrust, such as an injection molding machine, a ship steering cylinder, a hydrometric drive system, Such a single-rod cylinder includes a piston to which a rod is connected at one end so as to linearly reciprocate inside the cylinder body.

Electrohydrostatic actuators (EHA) composed of closed circuits mostly use single-rod hydraulic cylinders as actuators. In such a single rod cylinder, there is a volume flow difference due to the volume of the rod when inserting and withdrawing the piston, and compensation is absolutely necessary.

Here, the hydraulic apparatus of an electrohydrostatic actuator (EHA) includes an electric motor, a bidirectional hydraulic pump, a low-electric actuator, and the like. At this time, the flow rate / pressure of the operating fluid required in the system is controlled through the speed control and the torque control of the electric motor, and the direction of the piston can be controlled by switching the rotation of the electric motor in the forward / reverse direction.

In detail, in a conventional electrohydraulic hybrid actuator, a pair of supply lines provided at both ends of a bi-directional hydraulic pump are connected to both ends of a cylinder body, and a pair of pilot check valves and a low organic gas are provided between supply lines. At this time, each of the pilot check valves is connected to one supply line, and is opened / closed corresponding to the rotation direction of the bidirectional hydraulic pump as it is connected to another supply line by a pilot pipe, The operating oil flow direction can be switched.

As a result, a shortage of the hydraulic oil due to the volume of the rod due to the volume of the rod upon expansion of the piston is supplied to the head side of the cylinder body from the low oil level, and an excess of hydraulic oil due to the volume of the rod at the time of contraction of the piston is stored do.

However, conventionally, since the open / close state of each pilot check valve is switched by the pressure of the operating oil loaded on the pilot pipe, there is a constant delay time until the open / close state of each pilot check valve is switched There is a problem that the response is low.

Further, when the electric motor rotates at a high speed, cavitation is generated in the hydraulic oil due to a narrow flow path inside the pilot check valve, and it is difficult to precisely control the piston due to the delay of the closing of the pilot check valve when the direction of the electric motor is changed .

Thus, a technique has been devised in which a ball member is disposed in a casing in which a pilot hole is formed to replace the pilot tube, a pair of ball members are moved in the lateral direction according to the pressure of operating oil, and a channel between the pilot hole and the low- have.

However, when one of the pair of ball members is closed, the push bar is provided between the ball members so as to open the opposite side. In the low speed region, the both side channels connected to the low-pressure side by the push bar are slightly opened. Because of the structural problem that the degree of opening of the ball member in the neutral state is determined according to the length of the push bar, due to the assembly tolerance generated in the process of assembling the sleeve and the cover for mounting the ball member in the block, There is a problem that an individual difference occurs.

Also, in the high-speed region, back pressure is generated on the opposite side of the low-temperature side in the process of opening one side of the ball member, so that the noise and leakage are generated in the ball member and the size of the casing is increased And the like.

Korean Patent Publication No. 10-2012-0072614

In order to solve the above problems, the present invention automatically compensates for a difference in volume flow generated in the input and output of a hydraulic cylinder, solves problems due to a change in performance according to the length of the push bar and leakage in a neutral state, An automatic flow compensation valve of an electrohydraulic hybrid actuator with improved productivity is provided.

In order to solve the above problems, according to the present invention, in order to compensate for a flow rate difference between one side and the other side of a hydraulic cylinder partitioned by a piston, the hydraulic fluid is supplied from the storage tank to one side of the hydraulic cylinder, An automatic flow compensation valve of an electrohydraulic hybrid actuator for controlling a flow direction, comprising: a compensation flow path connected to the storage tank; and a connection flow path extending from both ends of the compensation flow path to one side and the other side of the hydraulic cylinder, A compensating valve block in which an oil passage and an opening / closing passage are formed symmetrically with respect to each other on the outside and inside of the opposite ends of the connecting passage; And an outer circumferential portion provided in a pair symmetrical to the respective connecting flow passages so as to be pressurized by the pressure of the hydraulic fluid flowing into the metering passage, the outer circumferential portion having a slide groove portion formed therein for selectively opening and closing the opening / And a double poppet device slidably moved in the slide groove portion by an applied pressure and including an inner peripheral portion having a push bar connected to the inner portion thereof.

Here, the outer peripheral portion is formed with an opening hole portion for maintaining communication with the oil rail, and a narrow pipe hole through which the push bar is inserted is formed at an inner end thereof. The outer peripheral portion and the inner peripheral portion are respectively supported by an outer spring and an inner spring, .

A poppet-like opening / closing part is preferably formed between the outer peripheral part and the inner end of the opening / closing flow path, and between the inner peripheral part and the sipe hole.

At this time, on the outer circumference of the push bar, a pressing protrusion for pressing the inner edge of the narrow hole is formed to open the other side opening / closing flow path when one connecting flow channel is closed, and the length of the push bar and the pressing protrusion, It is preferable that the inner circumferential portion is set so as to be kept inserted into the slide groove portion.

Preferably, the outer circumferential portion and the inner circumferential portion have a plurality of groove portions formed along the circumferential direction.

Through the above solution, the present invention provides the following effects.

First, when the hydraulic oil is pressurized and inflowed to one side of the connecting flow path at the time of initial driving of the bidirectional gear pump, pressure acts on the pressure receiving area of the inner peripheral portion of the inner peripheral portion of the double poppet device to move quickly in either direction, And the other on the opposite side can be automatically opened. As a result, the opening and closing flow path can be quickly and stably opened and closed, so that the degree of precision can be controlled.

Second, since the inner and outer peripheral portions of the double poppet device are slidingly moved in a mutual manner, leakage can be prevented from occurring in a state in which both open / close flow paths are closed in a neutral state in which operation is stopped, Improvement. In addition, since the outer barrel poppet can be opened and closed at a large flow rate by using the push bar, suction performance improvement and back pressure formation in the return line can be prevented, and generation of noise and vibration can be minimized.

Thirdly, since the inner and outer circumferential portions are slidingly moved in a mutual manner, they are substantially in surface contact with each other, so that the automatic maintenance function is performed. Therefore, even when the flow rate / direction of the operating oil is abruptly changed, . ≪ / RTI >

Fourthly, poppet portions are respectively formed between the outer peripheral portion and the inner end of the opening / closing flow path and between the inner peripheral portion and the narrowing hole rim. Therefore, even if the processing tolerance is relatively large, the closing performance is excellent in a closed state. Even if the length is slightly different, since there is no initial leakage and the performance is not changed, a relatively large machining tolerance can be tolerated, so that manufacturing cost can be reduced.

Fifth, the push bar can be simply formed into a cylindrical shape having a cross sectional area less than the cross-sectional area of the connection channel without complicated processing through processing, welding, screwing, etc., and the economical efficiency of the product can be improved.

Sixth, since the meat ring grooves are formed on the outer surfaces of the inner and outer peripheral portions so that the inner and outer peripheral portions slide smoothly even when the inner and outer peripheral portions are in close contact with the inner surface of the connection passage, the sealing performance is improved and the driving reliability of the product can be improved.

1 illustrates an electrohydraulic hybrid actuator hydraulic system in accordance with an embodiment of the present invention.
2 is an enlarged view of an automatic flow compensation valve of an electrohydraulic hybrid actuator according to an embodiment of the present invention;
3 is a view showing a process of opening and closing a connection channel in an expansion process of a hydraulic cylinder according to an embodiment of the present invention.
4 is a view illustrating a process of opening and closing a connection channel in a process of shrinking a hydraulic cylinder according to an embodiment of the present invention.

Hereinafter, an automatic flow compensation valve of an electrohydraulic hybrid actuator according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a view showing an electrohydraulic hybrid actuator hydraulic system according to an embodiment of the present invention, and FIG. 2 is an enlarged view showing an automatic flow compensating valve of an electrohydraulic hybrid actuator applied to an embodiment of the present invention.

As shown in FIGS. 1 and 2, the automatic flow compensation valve 100 is applied to an electrohydrostatic actuator (EHA) system. Here, the electrohydraulic hybrid actuator system means a system in which the flow rate / pressure / flow direction of the hydraulic fluid is controlled through the speed / torque / rotation direction control of the electric motor 5. At this time, the automatic flow compensation valve 100 of the electrohydraulic hybrid actuator opens and closes a flow path connected to the oil storage tank 7 so that an operating fluid shortage portion is supplied from the oil storage tank 7 and an excess hydraulic oil is stored in the oil storage tank 7 .

On the other hand, the electrohydraulic hybrid actuator system includes a hydraulic cylinder 2, an automatic flow compensation valve 100, a storage tank 7, an electric motor 5, and a bi-directional hydraulic pump 6.

Here, the hydraulic cylinder 2 has one side 2a of the inner space defined by the piston 2c connected to one side discharge portion of the bidirectional hydraulic pump 6 through the first supply line 3, And the other side 2b is connected to the other side discharge portion of the bi-directional hydraulic pump 6 through the second supply line 4. [

In this case, the bidirectional hydraulic pump 6 may be provided with a driving gear and a driven gear which are connected to the electric motor 5 to be rotated, and a gear pump in which the suction and discharge directions are selectively reversed. The operation speed / pressure / direction of the hydraulic cylinder 2 is controlled by controlling the flow rate / pressure / direction of the hydraulic fluid through the speed / torque / rotation direction control of the electric motor 5 connected to the bidirectional hydraulic pump 6. Direction can be controlled.

More specifically, when the bidirectional hydraulic pump 6 sucks the working oil of the second supply line 4 and sends it to the first supply line 3, the hydraulic cylinder 2 is extended and driven, and the bidirectional hydraulic pump 6, The hydraulic cylinder 2 is reduced in size when it sucks the working oil from the first supply line 3 and sends it to the second supply line 4. [

That is, when the working oil is injected into the one side 2a of the hydraulic cylinder 2 through the first supply line 3, the piston 2c is moved in the expanded direction and the working oil on the other side 2b of the hydraulic cylinder 2 And is discharged to the second supply line 4. When the working oil is injected into the other side 2b of the hydraulic cylinder 2 through the second supply line 4, the piston 2c is moved in the direction in which the piston 2c is contracted and the hydraulic oil at one side 2a of the hydraulic cylinder 2 And is discharged to the first supply line 3.

On the other hand, as the flow path between the storage tank 7 and the supply lines 3, 4 is selectively opened and closed through the automatic flow compensation valve 100 of the electrohydraulic hybrid actuator, the volume of the cylinder rod 2d The difference between the amount of the hydraulic fluid injected and the amount of the generated hydraulic fluid can be compensated. That is, the hydraulic oil shortage at the time of cylinder expansion is supplemented from the storage tank 7 to the second supply line 4, and the hydraulic oil excess at the time of contraction of the cylinder can be stored from the first supply line 3 to the storage tank 7 have.

Here, the automatic flow compensation valve 100 is provided with a first supply line (not shown) along the operating oil dispensing direction of the bidirectional hydraulic pump 6 so as to compensate for a difference in flow rate between one side 2a and the other side 2b of the hydraulic cylinder 2 3 and the second supply line 4 are selectively communicated with the storage tank 7.

Accordingly, the automatic flow compensation valve compensates for the flow rate difference between the one side and the other side of the hydraulic cylinder generated due to the volume of the cylinder rod, thereby enabling precise control of the hydraulic cylinder.

In particular, the automatic flow compensation valve 100 includes a compensation valve block 10 and a dual poppet arrangement 20, 21 symmetrically disposed to be slidably moved within the compensation valve block 10. At this time, the compensation valve block 10 may be provided in the shape of a square pillar block having various flow paths penetrated therein.

The compensating valve block 10 includes a compensation channel 11 connected to the reservoir tank 7 and a pair of first connection channels 11 extending symmetrically from both ends of the compensation channel 11, (12) and a second connection passage (13) are formed. Specifically, the compensation passage 11 is formed in a vertical direction so that the lower end thereof is connected to the oil storage tank 7, and the first and second connection passages 12 and 13 extend from the upper end of the compensation passage 11 to both sides As shown in Fig.

On the other hand, metering grooves 12a and 13a and open / close flow paths 12b and 12b are formed on the outside and inside of both ends of each of the connection flow paths 12 and 13 so that hydraulic oil supplied and discharged to one side and the other side of the hydraulic cylinder 2 flows. 13b are formed symmetrically with each other.

The oil supply passages 12a and 13a and the opening and closing flow paths 12b and 13b communicate with one side 2a and the other side 2b of the hydraulic cylinder 2, respectively. The first metering passage 12a and the first opening and closing passage 12b are connected to the one side 2a of the hydraulic cylinder 2 through the first supply line 3 and the second metering passage 13a, And the second opening and closing flow path 13b is connected to the other side 2b of the hydraulic cylinder 2 through the second supply line 4. [

More specifically, in the present embodiment, the oil lines 12a and 13a and the opening and closing flow paths 12b and 13b are communicated directly with the hydraulic cylinder 2 through branch lines 3a and 4a branched from the respective supply lines 3 and 4 As shown and described by way of example. Of course, the oil supply passages 12a and 13a and the opening and closing flow passages 12b and 13b may indirectly communicate with the respective supply lines 3 and 4 via the bidirectional hydraulic pump 6.

In this case, both end portions of the connection channels 12 and 13 may be formed integrally with the compensation valve block 10, but for convenience of manufacture, the switching valves 12a and 13a and the switching valves 12b and 13b, And the tubes (a1, a2) are connected to both ends of the compensation valve block (10). At this time, a space communicating with each of the supply lines (3,4) to the branch lines (3a, 4a) is formed in each of the switching valve tubes.

Meanwhile, the double poppet devices 20 and 21 are provided symmetrically in pairs in the connection flow paths 12 and 13 so as to be pressed by the pressure of the operating oil introduced into the oil supply passages 12a and 13a. Each of the double poppet devices 20 and 21 includes outer peripheral portions 32 and 33 and inner peripheral portions 22 and 23 which are slidably moved in the outer peripheral portions 32 and 33.

Specifically, the outer peripheral portions 32 and 33 are provided to selectively open and close the opening / closing flow paths 12b and 13b, respectively, and cylindrical slide groove portions 32d and 33d are formed therein. The inner circumferential portions 22 and 23 are slid within the slide groove portions 32d and 33d by the pressure acting on the outer pressure area of the outer side, and the push bars 45 are connected to each other between the inner side portions.

The outer peripheral portions 32 and 33 are substantially in surface contact with the inner peripheral surfaces of the switching valve tubes a1 and a2 of the connection flow paths 12 and 13 and the inner peripheral portions 22 and 23 are in contact with the outer peripheral portions 32 and 33 In a state of being in surface contact with the inner circumferential surface of the inner circumferential surface.

Accordingly, even when the connection flow paths 12 and 13 are arranged at an angle, opening and closing of the opening / closing flow paths 12b and 13b by the double poppet devices 20 and 21 can be accurately switched as described later. In addition, a plurality of meat ring grooves formed in the circumferential direction may be formed on the outer surface of the outer peripheral portions 32 and 33 and the outer surfaces of the inner peripheral portions 22 and 23, respectively.

Accordingly, a self-centering function can be provided in which the double poppet devices 20 and 21 are horizontally moved in a state where their centers are aligned within the connection channels 12 and 13. [

Each of the outer peripheral portions 32 and 33 is provided with opening hole portions 32c and 33c for maintaining communication with the oil supply passages 12a and 13a, And narrow tubular holes 32b and 33b through which the push bar 45 passes. At this time, the opening hole portions 32c and 33c are preferably formed at a predetermined angular interval along the circumferential direction so as to always maintain a state of communication with the oil supply passages 12a and 13a even when the outer peripheral portions 32 and 33 are moved Do.

At this time, a pressing protrusion 46 protruding in the circumferential direction is formed on the outer periphery of the push bar 45 so as to press and move the inner edges of the narrow tube holes 32b and 33b when the push bar 45 is moved.

The push bar 45 may be machined or bolted to the inner side peripheral portions 22 and 23 and the pushing protrusion 46 may be bolted to the push bar 45 to be coupled thereto.

The push bars 45 may be separated from each other at a central portion and may be provided in pairs. The outer diameter of the push bars 45 and the pushing projections 46 need to be larger than the narrow pipe holes 32b, 33b have.

The length of the push bar 45 and the pressing projection 46 is set such that the inner circumferential portion disposed on the other side of the one of the connecting flow paths 12 and 13 is inserted into the slide groove portion. Accordingly, as the length of the slide groove portions 32d and 33d is increased, the movement stroke of the inner peripheral portions 22 and 23 and the push bar 45 can be lengthened. As described later, The stroke of the double poppet devices 20 and 21 for opening and closing can be greatly increased. Therefore, according to the present invention, there is almost no leakage even in the neutral state, and the performance is not influenced by the length of the push bar.

The outer ends of the outer peripheral portions 32 and 33 and the outer peripheral ends of the inner peripheral portions 22 and 23 are elastically supported by outer springs 52a and 53a and inner springs 52b and 53b, do. The outer springs 52a and 53a and the inner springs 52b and 53b are extended to a length that maintains the elasticity of the outer peripheral portions 32 and 33 and both ends of the inner peripheral portions 22 and 23 when the hydraulic system is driven. .

Outer foam portions 32a and 33a are formed between the outer peripheral portions 32 and 33 and the inner ends of the opening and closing flow paths 12b and 13b and the inner peripheral portion 22.23 and the narrow pipe holes 32b and 33b, Inner poppet portions (22a, 23a) are formed between the rims. The poppet portion has a sloped cross section so as to close the flow of the hydraulic fluid during the pressure connection with the mating product. Such a double poppet structure can reduce the manufacturing cost because the closing performance is excellent in the closed state even if the machining tolerance or the assembly tolerance is relatively controlled, and the occurrence of the chattering phenomenon can be minimized as compared with the ball valve.

Hereinafter, the operation of the automatic flow compensation valve 100 of the electrohydraulic hybrid actuator will be described. For convenience of explanation, the configuration disposed in the first connection passage adds a designation "first" The configuration is described by adding the title "second".

As shown in FIG. 2, since the both side outer peripheral portions 32 and 33 are maintained in a state in which they are pressed inward by the outer springs 52a and 53a in the initial state of the bidirectional hydraulic pump 6, And 33a are in contact with the open and closed end stops 12c and 13c to keep the open / close flow paths 12b and 13b closed.

3 is a view illustrating a process of opening and closing a connection channel for expanding a hydraulic cylinder according to an embodiment of the present invention.

As shown in Fig. 3, the electric motor of the bi-directional hydraulic pump 6 must be compensated for the difference between the hydraulic oil injection amount and the discharge amount due to the volume difference of the cylinder rod 2d described above for the expansion of the hydraulic cylinder 2 . That is, the bidirectional hydraulic pump 6 sucks the operating oil of the second supply line 4 so that the operating oil is supplied to one side 2a of the hydraulic cylinder 2 in the process of expanding the hydraulic cylinder 2, To the line (3).

Here, the pressure of one side 2a of the hydraulic cylinder 2 and the first supply line 3 is increased, and the first connection line 3 and the first connection oil channel 12a, which are communicated with each other through the first oil line 12a, 12) is increased.

At this time, the pressure of the other side 2b of the hydraulic cylinder 2 and the pressure of the second supply line 4 is lowered due to suction of the working oil of the bidirectional hydraulic pump 6.

At this time, the pressurized pressurized oil acts on the hydraulic pressure area outside the inner circumference, and the first outer circumference portion 22 is deflected toward the inside of the first connection passage 12 like an independent actuator. Here, the water pressure area refers to an area viewed in a direction perpendicular to the horizontal movement direction of each inner peripheral portion 22. [

In detail, the pressure receiving area on the inner end face side of each of the inner peripheral portions 22, 23 disposed opposite to the connection flow passages 12, 13 is reduced by the cross sectional area occupied by the push bar 45, The pressure receiving area on the outer end face side is larger than the pressure receiving area on the inner end face side. Since the inner peripheral surface side watertight area of the inner peripheral portions 22 and 23 is connected to the tank, even if the hydraulic cylinder 2 is in the transitional state of expansion and contraction, a pressure acts on the outer peripheral surface of the inner peripheral portions 22 and 23 It can be quickly deflected to the inside. For example, when the hydraulic oil flows into the first connection passage 12, the first inner circumferential portion 22 is instantaneously moved inward rapidly.

The first inner main portion 22 is moved to the inside of the first slid groove portion 32d and the first inner poppet portion 22a is moved to the first sagittal hole 32b in accordance with the operation principle of the inner portions 22, So as to firmly close the first squeeze hole 32b. At this time, the pressure acting in the outer direction of the second inner circumference 23 is in a state in which the pressure is lowered due to the suction of the bidirectional hydraulic pump 6, so that the movement direction of the first inner circumference 22 described above is affected Do not.

The first inner circumferential portion 22 is moved to the inside of the inner circumferential portion by the above-mentioned operating principle, and the first inner circumferential portion 22 is moved to the first outer circumferential portion (that is, 32 are pressed inward through the rim of the first internal poppet portion 22a. At this time, the first outer poppet portion 32a of the first outer peripheral portion 32 comes into pressure contact with the inner end 12c of the first opening and closing flow path 12b and the first opening and closing flow path 12b is quickly closed.

On the other hand, the second protruding portion 46 of the push bar 45 is further opened by moving the second outer peripheral portion 33 outwardly. The piston 2c is moved to the other side 2b of the hydraulic cylinder 2 and the other side 2b of the hydraulic cylinder 2 2b) is quickly discharged to the second supply line (4).

At this time, the volume flow rate discharged from the other side 2b of the hydraulic cylinder 2 due to the volume difference of the cylinder rod 2d is smaller than the operating flow rate injected into the one side 2a of the hydraulic cylinder 2. Therefore, a part of the hydraulic oil from the storage tank 7 is automatically sucked into the second supply pipe 4 through the second opening / closing passage 13b, and the difference in the operating flow rate is compensated for, so that the hydraulic cylinder can be operated accurately and stably Do.

Thus, the first opening / closing passage 12b is closed and the second opening / closing passage 13b is opened quickly, and the moving stroke of the push bar 45 for opening the second opening / The second open / close flow path 13b can be sufficiently opened, so that the supply of the shortage of flow rate is smoothly performed in the second supply line 4, so that the cavitation caused by the suction resistance The occurrence can be minimized. As a result, the amount of noise and vibration generated can be minimized.

Since the push bar 45 is moved by the pressure acting on the pressure receiving area of the outer end face of the first inner peripheral portion 22, the elasticity of the inner springs 52b and 53b and the outer springs 52a and 53a is minimized Preferably set. As a result, it is possible to minimize an obstacle to the closing due to the force of the opposite surface spring, and the opening and closing flow paths 12b and 13b can be quickly opened and closed.

Meanwhile, FIG. 4 is a view illustrating an open / close state of a connection channel for reducing a hydraulic cylinder according to an embodiment of the present invention. Even in this reduction process, the dead zone can be eliminated and the response characteristic can be improved by the symmetrical principle described with reference to FIG. 3 in the low speed section.

As shown in FIG. 4, the bidirectional hydraulic pump 6 sucks the operating oil of the first supply line 3 so that the hydraulic oil is supplied to the other side 2b for the reduction of the hydraulic cylinder 2, (4).

At this time, the operating oil pressure of the other side 2b of the hydraulic cylinder 2 and the second supply line 4 is increased, and the second connection passage 13 (third communication passage) communicating with the second supply line 4 and the branch passage 4a ) Is increased.

The second inner peripheral portion 23 is moved to the inside of the second slid groove portion 33d and the second inner poppet portion 23a is pressed against the rim of the second narrowing pipe 33b due to the above- Thereby closing the second sipe-bore hole 33b. At this time, the pressure in the first inner circumference 22 does not affect the moving direction of the second inner circumference 23 described above because the pressure due to the suction of the bidirectional hydraulic pump 6 is low.

The second inner peripheral portion 23 presses the second outer peripheral portion 33 inward and the second outer poppet portion 33a of the second outer peripheral portion 33 presses the inner end 13c So as to quickly close the second opening / closing flow path 13b.

On the other hand, as the push bar 45 is moved, the pressurizing protrusion 46 presses the first outer peripheral portion 32 outward to further open the first open / close flow path 12b. As the hydraulic pressure in the other side 2b of the hydraulic cylinder 2 increases, the piston 2c is moved to one side 2a of the hydraulic cylinder 2 and the other side 2a of the hydraulic cylinder 2 ) Is quickly discharged to the first supply line (3).

At this time, the volume flow rate discharged from the one side 2a of the hydraulic cylinder 2 due to the volume difference of the cylinder rod 2d is larger than the operation flow rate injected into the other side 2b of the hydraulic cylinder 2. Therefore, a part of the operating oil discharged from one side 2a of the hydraulic cylinder 2 flows into the storage tank 7 through the first opening / closing flow path 12b, and the difference in the operating flow amount is compensated, And stable operation is possible.

Thus, the second cover opening / closing passage 13b is closed and the first opening / closing passage 12b is opened quickly. In addition, since the stroke of the push bar 45 for opening the first opening / closing flow path 12b can be made as long as possible regardless of the initial leakage in the neutral state, the back pressure formation in the first supply line 3 is minimized And the generation of noise and vibration can be minimized.

Since the push bar 45 is moved by the pressure acting on the pressure receiving area of the outer end face of the second inner peripheral portion 23, the resilience of the inner springs 52b, 53b and the outer springs 52a, 53a is minimized Preferably set. As a result, it is possible to minimize an obstacle to the closing due to the force of the opposite spring, and the opening / closing flow paths 12b and 13b can be quickly opened and closed.

As described above, the present invention is not limited to the above-described embodiments, and variations and modifications may be made by those skilled in the art without departing from the scope of the present invention. And such modifications are within the scope of the present invention.

2: Hydraulic cylinder 2d: Cylinder rod
3: first supply line 4: second supply line
5: Electric motor 6: Bi-directional hydraulic pump
7: Reservoir tank 100: Automatic flow compensation valve
10: compensation valve block 20,21: double poppet device
22: 1st inner housewife 23: 2nd inner housewife
32: first outer circumferential portion 33: second outer circumferential portion
45: push bar 46: pressure projection

Claims (5)

An automatic control of an electric hydraulic hybrid actuator that controls the flow direction of hydraulic oil from one side of the hydraulic cylinder to the other side of the hydraulic cylinder in accordance with the hydraulic oil dispensing direction of the bidirectional hydraulic pump so that the difference in flow rate between one side and the other side of the hydraulic cylinder partitioned by the piston is compensated. In the flow compensation valve,
And an oil passage and an opening / closing passage are formed in the connection passage so as to allow hydraulic oil supplied and discharged to one side and the other side of the hydraulic cylinder to flow therethrough, and a compensation passage connected to the storage tank and a connection passage extending from both ends of the compensation passage, A compensation valve block formed symmetrically with respect to the outer side and the inner side of both ends of each of the first and second end portions; And
An outer peripheral portion provided in a pair symmetrical to the respective connecting flow passages so as to be pressurized by the pressure of the operating oil introduced into the oil passage and having a slide groove portion formed therein for selectively opening and closing the opening and closing flow passage, And a double poppet device slidably moved in the slide groove part by a pressure lowered, wherein an inner peripheral part of the inner part is connected to a push bar. The method according to claim 1,
Wherein the outer peripheral portion is formed with an opening hole portion for maintaining the communicating state with the metering passage, and a narrow pipe hole through which the push bar passes is formed at an inner end thereof,
Wherein the outer peripheral portion and the inner peripheral portion are elastically supported by an outer spring and an inner spring, respectively. 3. The method of claim 2,
Wherein a poppet portion is formed between the outer peripheral portion and the inner end of the opening / closing flow path, and between the inner peripheral portion and the narrowed pipe hole rim, respectively. 3. The method of claim 2,
Wherein a pushing protrusion for pressing an inner edge of the narrowing hole is formed on the outer periphery of the push bar so as to open the other side opening /
Wherein a length of the push bar and the pressing projection is set such that the other inner peripheral portion of the push bar and the pressing projection is inserted into the slide groove when the one connection channel is closed. The method according to claim 1,
Wherein an outer surface of the outer peripheral portion and an outer surface of the inner peripheral portion are provided with a plurality of meat ring grooves formed in a circumferential direction.

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