CN115898805A - Actuator piston and driving device comprising same - Google Patents

Actuator piston and driving device comprising same Download PDF

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Publication number
CN115898805A
CN115898805A CN202111401426.4A CN202111401426A CN115898805A CN 115898805 A CN115898805 A CN 115898805A CN 202111401426 A CN202111401426 A CN 202111401426A CN 115898805 A CN115898805 A CN 115898805A
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CN
China
Prior art keywords
piston
diameter
actuator
small
main body
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Pending
Application number
CN202111401426.4A
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Chinese (zh)
Inventor
俞在瓒
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Joint Stock Co Motuole
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Joint Stock Co Motuole
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Publication date
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Publication of CN115898805A publication Critical patent/CN115898805A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0602—Component parts, details
    • F03C1/0605—Adaptations of pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
    • F03C1/00—Reciprocating-piston liquid engines
    • F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
    • F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
    • F03C1/0678—Control
    • F03C1/0686—Control by changing the inclination of the swash plate

Abstract

An embodiment of the present invention relates to an actuator piston capable of changing an angle of a swash plate inside a hydraulic drive device, the actuator piston including: a piston body; an actuator recess formed in an outer circumferential surface of the piston main body along an outer circumferential direction of the piston main body; and a slit formed in an area of an outer circumferential surface of the piston main body along a longitudinal direction of the piston main body.

Description

Actuator piston and driving device comprising same
Technical Field
The present invention relates to a drive device that generates power by hydraulic pressure and an actuator piston provided in the drive device.
Background
Typically, a drive device, such as a pump driven by hydraulic pressure, is provided to the construction machine. Such a drive device provides power for the operation of the working equipment of the construction machine.
Before the shipment of the commodity, the driving device performs a process of matching the discharge pressure of the pump based on the input current. Specifically, in a state where the discharge port of the drive device is completely blocked, the input current is increased, and the swash plate is finely controlled by the operation of the pressure control regulator to control the pressure.
However, the control in the state of completely blocking the discharge port is the control under a slight volume change, and therefore it is difficult to stabilize the control. In particular, in the low pressure region, a Bleed-Off flow rate is reduced due to oil leakage inside the drive apparatus, so that it is difficult to rapidly reduce a shock due to a pressure change, and thus a pressure instability control problem such as Hunting occurs.
Therefore, there is a need for a drive device that can solve the problem of pressure instability control such as hunting without reducing the efficiency of the construction machine.
Documents of the prior art
Patent literature
Patent document 0001: korean granted patent publication No. 10-0429928
Disclosure of Invention
Embodiments of the present invention provide an actuator piston and a driving apparatus including the same that improve abnormal pressure oscillation phenomenon in a specific region when the driving apparatus using hydraulic pressure operates.
According to an embodiment of the present invention, an actuator piston capable of changing an angle of a swash plate inside a hydraulic drive device includes: a piston main body; an actuator recess formed in an outer circumferential surface of the piston main body along an outer circumferential direction of the piston main body; and a slit formed in an area of an outer circumferential surface of the piston main body along a longitudinal direction of the piston main body.
The plurality of actuator grooves may be arranged to be spaced apart from each other in a longitudinal direction of the piston main body.
The slit may penetrate a region of the plurality of actuator grooves.
The plurality of slits may be arranged at intervals along an outer circumferential direction of the piston main body.
Further, a ratio of a sum of sectional areas of the plurality of slits to a sectional area of the piston main body in a cross section in a direction intersecting with a longitudinal direction of the piston main body may be in a range of 0.002 to 0.005.
Also, a ratio of the length of the slot to the overall length of the piston body may be in a range of 0.78 to 0.8.
Also, the cross-section of the slit may have a shape that is narrower toward the center of the piston body.
Alternatively, the cross section of the slit may be formed in a straight line in a region adjacent to the center of the piston main body.
Alternatively, the cross section of the slit may be formed in a curved line in a region adjacent to the center of the piston main body.
Alternatively, a driving device according to an embodiment of the present invention includes: a main body, which is supplied with hydraulic pressure from the outside and is provided with a large-diameter chamber and a small-diameter chamber; a swash plate disposed inside the main body; a large-diameter actuator part capable of changing the swash plate, including a large-diameter actuator piston at least a part of which is inserted into the large-diameter chamber; and a small-diameter actuator part capable of changing the swash plate, including a small-diameter actuator piston at least a part of which is inserted into the small-diameter chamber and capable of communicating the hydraulic pressure of the small-diameter chamber to the inside of the main body.
Further, the small diameter actuator section may further include: a small-diameter connecting rod disposed between the swash plate and the small-diameter actuator piston; and a slit groove formed in a part of an outer peripheral surface of the small diameter actuator piston so as to be recessed in a longitudinal direction of the small diameter actuator piston, the slit groove communicating a hydraulic pressure of the small diameter chamber to an inside of the main body.
And, a side of the slot that is opposite and adjacent to the swash plate may be opened.
Further, the length of the slit may be relatively smaller than the total length of the small-diameter actuator piston.
According to the embodiments of the present invention, the actuator piston and the driving apparatus including the same have an effect that pressure variation can be effectively suppressed by improving an abnormal pressure oscillation phenomenon in a specific region when the driving apparatus operates.
Drawings
Fig. 1 is a sectional view showing a driving device provided with an actuator piston according to an embodiment of the present invention.
Fig. 2 is a diagram showing an actuator piston according to an embodiment of the present invention.
Fig. 3 is a view showing a partial cross section in the longitudinal direction in fig. 2.
Fig. 4 is a view showing a cross section in a direction perpendicular to the longitudinal direction in fig. 2.
Fig. 5 is a diagram showing a slot of an actuator piston according to still another embodiment of the present invention.
Fig. 6 is a diagram showing a slot of an actuator piston according to another embodiment of the present invention.
Fig. 7 and 8 are views showing the operation of the actuator piston according to the present invention.
Fig. 9 shows a pressure correction map based on the operating state of the conventional drive device.
Fig. 10 shows a pressure correction graph of an operating state of the driving apparatus according to an embodiment of the present invention.
Description of reference numerals
100: a main body; 101: a drive device;
110: a large diameter chamber; 120: a small diameter chamber;
250: a sloping plate; 300: a large-diameter actuator section;
320: a large diameter actuator piston;
400: a large-diameter actuator section; 420: a small diameter actuator piston;
420. 426, 427: an actuator piston; 422: an actuator recess;
425: a slot; 421: a piston body.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily carry out the invention. The present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.
The drawings are of a schematic illustration and are not to scale. Relative dimensions and proportions of parts of the figures have been shown exaggerated or reduced in size, relative to their size, for the sake of clarity and convenience in the drawings, any dimensions being merely exemplary and not limiting. Moreover, to illustrate similar features, the same reference numerals are used for identical structures, elements, or components that appear in more than two figures.
The embodiments of the present invention specifically show desirable embodiments of the present invention. As a result, many variations of the illustration are expected. Thus, embodiments are not limited to the specific form of the regions shown, for example, including morphological changes based on fabrication.
An actuator piston 420 according to an embodiment of the present invention will be described below with reference to fig. 1 to 4.
As shown in fig. 1, the actuator piston 420 can change the angle of the swash plate 250 disposed inside the drive device 101. Specifically, the swash plate 250 disposed inside the drive device 101 receives hydraulic pressure from the outside of the drive device 101 to move the actuator piston 420 so as to be able to change the angle.
As shown in fig. 1 and 2, the actuator piston 420 includes a piston body 421, an actuator groove 422, and a slot 425.
At least a part of the piston main body 421 is inserted into and moved in the small diameter chamber 120 for supplying the hydraulic pressure of the driving device 101. The piston main body 421 may be formed to be long in one direction, and may have a ring-shaped cross section. Specifically, the hydraulic pressure flows from the outside into the small-diameter chamber 120, and thereby the piston main body 421 can move in a direction in which a portion is drawn out from the small-diameter chamber 120 and change the angle of the swash plate 250.
The actuator groove 422 is recessed in the outer circumferential surface of the piston main body 421. Also, the actuator groove 422 is formed along the outer circumferential direction of the piston main body 421. Specifically, the actuator groove 422 is retained inside thereof by hydraulic pressure, so that friction can be reduced when the piston main body 421 moves along the small diameter chamber 120. That is, the actuator groove 422 can improve lubrication between the outer peripheral surface of the piston main body 421 and the inner surface of the small-diameter chamber 120.
The slit 425 is formed in a region of the outer circumferential surface of the piston main body 421 so as to be recessed along the longitudinal direction of the piston main body 421. Specifically, the slot 425 may be formed in a direction crossing a forming direction of the actuator groove 422. Also, a side of the slot 425 opposite to and adjacent to the swash plate 250 may be opened.
With the above configuration, the slit 425 is formed in the actuator piston 420 disposed inside the drive device 101, and the external hydraulic pressure flowing into the region where the slit 425 is provided can be interlocked with the inside of the drive device 101 according to the angle of the swash plate 250 for driving the actuator piston 420, so that the oscillation phenomenon of the drive device 101 in a specific section can be improved. Specifically, for the driving of the actuator piston 420, the slot 425 may link the external hydraulic pressure flowing into the region where it is provided with the inside of the driving device 101 according to the angle to suppress the pressure variation.
As shown in fig. 2 to 3, a plurality of actuator grooves 422 according to an embodiment of the present invention may be disposed at intervals along a longitudinal direction of the piston main body 421.
The actuator groove 422 may be recessed along the outer circumferential surface of the piston main body 421, and a plurality of actuator grooves 422 may be formed to be spaced apart along the longitudinal direction of the piston main body 421.
The plurality of actuator grooves 422 are formed to be spaced apart in the longitudinal direction of the piston main body 421, so that friction between the outer periphery of the actuator piston 420 and the inside of the small-diameter chamber 120 can be reduced by the fluid retained in the inside thereof. Thus, friction of the actuator piston 420 according to an embodiment of the present invention may be reduced by the fluid retained in the actuator groove 422, thereby preventing the actuator piston 420 from being broken, and thus extending the life thereof.
Also, as shown in fig. 2 and 3, a slot 425 according to an embodiment of the present invention may be formed through a region of the plurality of actuator grooves 422.
The slot 425 may penetrate a region of the plurality of actuator grooves 422 and be recessed along the length of the piston body 421. The slit 425 allows the inside of the small-diameter chamber 120 and the outside of the small-diameter chamber 120 inside the drive device 101 to communicate with each other in accordance with the movement of the piston main body 421.
Specifically, the length L of the slot 425 1 May be relatively smaller than the overall length L of the piston body 421. One side of the slot 425 opposite adjacent to the swash plate 250 may be open at the piston main body 421 and the other side of the slot 425 may be blocked.
Therefore, the slit 425 allows the small-diameter chamber 120 to communicate with the inside of the drive device 101 in accordance with the movement of the piston main body 421. Specifically, when a region of the slit 425 is formed so as to be inserted into the small-diameter chamber 120, the piston main body 421 can move the hydraulic pressure flowing from the outside into the small-diameter chamber 120 through the slit 425 toward the inside of the drive device 101.
Also, as shown in FIG. 3, the length L of the slot 425 of one embodiment of the present invention 1 The ratio to the overall length L of the piston body 421 may be in the range of 0.78 to 0.8. In particular, L 1 L =0.78 to 0.8.
When the length L of the slot 425 1 When the ratio to the total length L of the piston main body 421 is less than 0.78, communication with the inside of the driving device 101 is not made in a region where oscillation is likely to occur, and thus, an effect of improving the oscillation phenomenon of the driving device 101 in a specific section can be obtained.
And, when the length L of the slot 425 is 1 When the ratio to the total length L of the piston main body 421 is greater than 0.8, the communication with the inside of the drive device 101 is also established over a range in which the oscillation is improved, and the volume loss increases. Therefore, it is difficult to expect the effect of minimizing the volume loss of the driving device 101, which is a feature of the present invention. That is, the driving device 101 of the present invention includes the above-described slot 425, and thus, it is possible to reduce oscillation and minimize a volume loss.
As shown in fig. 4, the plurality of slots 425 according to an embodiment of the present invention may be arranged to be spaced apart along the outer circumferential direction of the piston main body 421.
The slits 425 may be recessed along the longitudinal direction of the piston main body 421, and the slits 425 are radially spaced apart from each other on the piston main body 421 with respect to the longitudinal direction of the piston main body 421.
Accordingly, a plurality of slits 425 are formed in the piston main body 421, and the hydraulic pressure in the small-diameter chamber 120 is communicated to the interior of the drive device 101 in which the swash plate 250 is disposed along the slits 425 in the outer surface of the piston main body 421, whereby pressure fluctuations can be effectively suppressed.
Also, as shown in FIG. 4, the sum A of the cross-sections of the plurality of slots 425 according to one embodiment of the present invention s The ratio to the sectional area a of the piston body 421 calculated on the basis of the outer diameter D of the piston body 421 may be in the range of 0.002 to 0.005. Utensil for cleaning buttockBody ground can be A s and/A = 0.002-0.005. In this case, the cross section may be a cross section of the piston main body 421 in a direction perpendicular to the longitudinal direction of the piston main body 421. As an example, it may be A s ＝A s1 +A s2 +A s3 +A s4 +…+A sn . I.e. A s May be the sum of the cross-sectional areas of the plurality of slots 425.
When the sum of the cross-sectional areas of the plurality of slots is A s When the ratio of the sectional area a of the piston main body 421 to the sectional area a is less than 0.002, the effect of improving the hunting phenomenon is insignificant because the bleed-off flow rate is insufficient. In particular, when having the above cross-sectional area, it is difficult to secure the bleed flow rate through the plurality of slots 425.
That is, the bleeding of high-pressure oil to the drain pipe may be accomplished by the plurality of slots 425. Further, the interior of the driving device 101 may provide a discharge space connected to a tank, not shown.
When the sum of the cross-sectional areas of the plurality of slots 425 is A s When the ratio of the sectional area a of the piston main body 421 to the sectional area a is more than 0.005, the discharge flow rate becomes excessive, and the oscillation phenomenon is improved, but the efficiency is lowered due to the increase of the volume loss. Specifically, the improvement effect of the hunting phenomenon can be expected by the bleed-off, but based on this, there is a problem that the efficiency of the drive device 101 is reduced due to an increase in volume loss caused by the leakage of the hydraulic pressure. Also, as shown in fig. 4, the cross-section of the slot 425 according to an embodiment of the present invention may have a shape that is narrower as it gets closer to the center of the piston main body 421.
The section of the slot 425 may have an inclined surface that is narrower as it gets closer to the center of the piston main body 421, and the hydraulic pressure of the small diameter chamber 120 may move along the inclined surface.
As an example, the cross-section of the slot 425 may be approximately "triangular".
Alternatively, as shown in fig. 5, the cross-section of the slot 425 according to an embodiment of the present invention may be formed to be a straight line in a region adjacent to the center of the piston main body 421.
The section of the slot 425 may be a plane in which a region adjacent to the center of the piston main body 421 is in a straight line, so that the hydraulic pressure of the small diameter chamber 120 may move along the plane.
As an example, the cross-section of the slot 425 may be approximately "quadrilateral".
Alternatively, as shown in fig. 6, the cross-section of the slot 425 according to an embodiment of the present invention may be formed to have a curved line in a region adjacent to the center of the piston main body 421.
The section of the slot 425 may be formed to be curved in a region adjacent to the center of the piston main body 421 so that the hydraulic pressure of the small diameter chamber 120 can move along the curved surface.
As an example, the cross-section of the slot 425 may be approximately "half-moon shaped".
With the above configuration, in the actuator piston 420 according to the embodiment of the present invention, the slit 425 is formed so that a region thereof is recessed along the longitudinal direction of the piston main body 421, so that the hydraulic pressure in the small-diameter chamber 120 can be selectively communicated with the interior of the drive device 101 according to the movement of the piston main body 421, and pressure fluctuation can be suppressed. Therefore, in the actuator piston 420 according to an embodiment of the present invention, a region of the slot 425 may be recessed along the length direction of the piston main body 421, and the abnormal pressure oscillation phenomenon may be effectively improved in a specific region of the driving device 101.
Hereinafter, a driving device 101 provided with an actuator piston 420 according to the present invention will be described with reference to fig. 1 to 8. Specifically, the driving device 101 is a device that generates power using hydraulic pressure such as a pump.
The drive device 101 includes a main body 100, a swash plate 250, a large-diameter actuator unit 300, and a small-diameter actuator unit 400.
The body 100 is formed with a large diameter chamber 110 and a small diameter chamber 120 to which hydraulic pressure is supplied from the outside. The large-diameter chamber 110 and the small-diameter chamber 120 are supplied with hydraulic pressure supplied through a valve not shown.
The area of the large diameter chamber 110 may be relatively larger than the area of the small diameter chamber 120. Also, the large diameter chamber 110 and the small diameter chamber 120 may be spaced apart from each other and formed inside the body 100. Specifically, a region of one end portion of the small-diameter chamber 120 may be formed with a larger diameter so that the hydraulic pressure can flow thereinto. The inclination angle of the swash plate 250 is controlled by the difference in the force of the hydraulic pressure supplied to the large diameter chamber 110 and the small diameter chamber 120.
Specifically, the large diameter chamber 110 supplies and discharges hydraulic pressure under the control of an unillustrated Regulator (Regulator). The small-diameter chamber 120 directly supplies the discharge pressure of the drive device 101.
A swash plate 250 is disposed inside the body 100. The inclination angle of the swash plate 250 can be controlled, whereby the flow rate of the hydraulic pressure discharged from the drive device 101 can be adjusted. That is, the flow rate of the hydraulic oil required for the operation of the working equipment connected to the drive device 101 can be adjusted by controlling the inclination angle of the swash plate 250.
The large-diameter actuator portion 300 includes a large-diameter actuator piston 320. At least a part of the large-diameter actuator piston 320 is inserted into the large-diameter chamber 110. Also, the large diameter actuator piston 320 may change the swash plate 250. Specifically, the large-diameter actuator piston 320 may move and change the angle of the swash plate 250 according to the hydraulic oil flowing into the large-diameter chamber 110.
The small-diameter actuator portion 400 includes a small-diameter actuator piston 420. At least a part of the small-diameter actuator piston 420 is inserted into the small-diameter chamber 120. The small diameter actuator piston 420 can change the swash plate 250. The small-diameter actuator piston 420 can communicate the hydraulic pressure of the small-diameter chamber 120 into the main body 100. Specifically, the small-diameter actuator piston 420 is movable and changes the angle of the swash plate 250 in accordance with the hydraulic oil flowing into the small-diameter chamber 120.
In addition, the small-diameter actuator portion 400 of the driving device 101 according to an embodiment of the present invention may further include a small-diameter connecting rod 410 and a slot 425.
The small diameter actuator piston 420 may have the same structure as the actuator piston 420 of the embodiment of the invention described above.
The small-diameter connecting rod 410 is disposed between the small-diameter actuator piston 420 and the swash plate 250, moves together with the movement of the small-diameter actuator piston 420, and transmits the movement to the swash plate 250 to change the angle of the swash plate 250.
Further, a small-diameter contact hole 423 into which the small-diameter connecting rod 410 is inserted and supported and a small-diameter piston flow passage through which the hydraulic pressure of the small-diameter chamber 120 can be transmitted to the small-diameter flow passage 411 may be formed in the piston main body 421 of the small-diameter actuator piston 420.
The drive device 101 according to an embodiment of the present invention may further include a small-diameter connection member 430 that forms a flow path that can communicate with the small-diameter flow path 411 and that can support the small-diameter connecting rod 410 on the swash plate 250.
In addition, the large-diameter actuator unit 300 of the driving device 101 according to an embodiment of the present invention may further include a large-diameter link 310.
The large diameter connecting rod 310 is disposed between the large diameter actuator piston 320 and the swash plate 250, moves together with the movement of the large diameter actuator piston 320, and transmits the movement to the swash plate 250 to change the angle of the swash plate 250. Specifically, a large-diameter flow passage similar to the small-diameter flow passage 411 formed in the small-diameter connecting rod 410 may be formed inside the large-diameter connecting rod 310.
In addition, the driving device 101 according to an embodiment of the present invention may further include a large-diameter connection member 330 that is formed with a flow path that can communicate with the large-diameter flow path and supports the large-diameter link 310 on the swash plate 250.
The driving device 101 according to an embodiment of the present invention may further include a driving shaft 200, a bearing 500, an actuator piston 420, and a valve plate 600.
The driving shaft 200 may penetrate the swash plate 250 and at least a portion thereof may be inserted into and supported by the body 100.
The bearing 500 may be disposed between the driving shaft 200 and the main body 100 to support the driving shaft 200 in a rotating manner.
One side of the actuator piston 420 may be connected to the swash plate 250, and the other side may be inserted into the cylinder and may be contracted and extended along a volume chamber formed inside the cylinder. A plurality of actuator piston pistons 420 may be spaced apart from one another along the swash plate 250.
The valve plate 600 may be disposed opposite to the cylinder, formed with a suction port and a discharge port, and communicated with a volume chamber formed inside the cylinder.
The operation of the drive device 101 provided with the actuator piston 420 of the present invention will be described below with reference to fig. 7 and 8.
As shown in fig. 7, when the angle of the swash plate 250 is in the range of 0 to 0.5 degrees, one end of the small-diameter actuator piston 420 adjacent to the other side of the slot 425 is inserted into a region of the small-diameter chamber 120 that is expanded in diameter. In this case, the other side of the slit 425 formed in the piston main body 421 of the small-diameter actuator piston 420 is inserted into a region of the small-diameter chamber 120 that is expanded in diameter, and the piston main body 421 that forms one end of the slit 425 faces the inner peripheral surface of the region of the small-diameter chamber 120 that is not expanded in diameter. Therefore, the slit 425 can communicate the hydraulic pressure by moving the hydraulic oil flowing into a region of the small-diameter chamber 120 formed by expanding the diameter of the other side of the slit 425 toward the one side of the slit 425 along the longitudinal direction of the slit 425.
When the angle of the swash plate 250 is in the range of 0 to 0.5 degrees, the hydraulic pressure supplied to the small-diameter chamber 120 can be connected to the inside (discharge space) of the drive device 101 through the narrow groove 425, and pressure fluctuation due to the sequential control can be suppressed. That is, the slot 425 may vent the discharge pressure of the drive device 101 when the angle of the swash plate 250 is in the range of 0 degrees to 0.5 degrees.
As shown in fig. 8, when the angle of the swash plate 250 is greater than 0.5 degrees, the piston main body 421 moves along the small-diameter chamber 120, and the piston main body 421 in the region where the narrow groove 425 is not formed slides while facing the inner peripheral surface of the small-diameter chamber 120. In this case, the slit 425 is closed, and the pressure flowing into the small-diameter chamber 120 cannot move, so that the efficiency does not decrease due to the volume loss.
The meaning indicated by the line of each graph in fig. 9 and 10 will be briefly described.
The discharge pressure shown in fig. 9 and 10 is the discharge pressure of the pump as the driving device 101.
The second Pressure (2 nd Pressure) is a Pressure supplied to a Regulator (Regulator) of the pump through an electronic proportional control valve (EPPRV) not shown. That is, the second pressure is a pressure value that linearly changes according to the input current.
The Degree (Degree) is the swash plate angle of the swash plate 250.
Also, the Current (Current) is a Current currently applied to the driving device.
When a current is applied to the driving device Step by Step, a secondary pressure of an electronic proportional control valve (not shown) is applied to the regulator Step by Step, in which case the swash plate is instantaneously increased, the discharge pressure is increased due to the clogging of the discharge pipe, and the regulator recognizes the above and rapidly repeats the process of reducing the pressure, so that the predetermined pressure can be controlled when a specific current is applied.
As described above, fig. 9 shows a state (oscillation) in which the swash plate angle and the discharge pressure vary considerably due to the above-described control irregularity in the specific region. That is, the oscillation state section in which the discharge pressure is also reduced due to the occurrence of chattering of the swash plate angle is partially disclosed in the illustrated drawings.
Fig. 10 shows a graph of control without the hunting phenomenon when the present invention is employed. Specifically, the actuator piston of an embodiment of the present invention may include a slot so that the discharge of the high-pressure oil leaking to the discharge pipe may be smoothly performed. Therefore, chattering of the swash plate angle and oscillation of the drive device 101 can be effectively reduced.
Although the embodiments of the present invention have been described with reference to the drawings, it will be understood by those skilled in the art to which the present invention pertains that the present invention may be implemented in other specific embodiments without changing the technical spirit or essential features of the present invention.
Therefore, it should be understood that the above-described examples are merely illustrative in all respects and not restrictive, the scope of the present invention being indicated by the scope of the claims of the invention rather than the above detailed description, and all modifications and variations derived from the meaning, scope and equivalent concept of the claims of the invention should be construed as being included in the scope of the present invention.

Claims (13)

1. An actuator piston capable of changing an angle of a swash plate inside a hydraulic drive device, comprising:
a piston body;
an actuator recess formed in an outer circumferential surface of the piston main body along an outer circumferential direction of the piston main body; and
and a slit formed in an area of an outer circumferential surface of the piston body along a longitudinal direction of the piston body.
2. The actuator piston of claim 1 wherein a plurality of said actuator grooves are spaced apart along the length of said piston body.
3. The actuator piston of claim 2 wherein said slot is formed through a region of a plurality of said actuator grooves.
4. The actuator piston according to claim 2, wherein a plurality of the slits are arranged at intervals along an outer circumferential direction of the piston main body.
5. The actuator piston according to claim 4, wherein a ratio of a sum of sectional areas of the plurality of slits to a sectional area of the piston main body in a sectional plane in a direction intersecting a longitudinal direction of the piston main body is in a range of 0.002 to 0.005.
6. The actuator piston of claim 1 wherein the ratio of the length of said slot to the overall length of said piston body is in the range of 0.78 to 0.8.
7. The actuator piston of claim 1 wherein said slot has a cross-section that is narrower closer to the center of said piston body.
8. The actuator piston of claim 1 wherein said slot is formed in a linear cross-section in a region adjacent the center of said piston body.
9. The actuator piston of claim 1 wherein said slot is curved in cross-section in a region adjacent the center of said piston body.
10. A drive device, comprising:
a main body, which is supplied with hydraulic pressure from the outside and is provided with a large-diameter chamber and a small-diameter chamber;
a swash plate disposed inside the body;
a large-diameter actuator part capable of changing the swash plate, including a large-diameter actuator piston at least a part of which is inserted into the large-diameter chamber; and
and a small-diameter actuator section which is capable of changing the swash plate and includes a small-diameter actuator piston at least a part of which is inserted into the small-diameter chamber and which is capable of communicating the hydraulic pressure of the small-diameter chamber to the inside of the main body.
11. The drive device according to claim 10, wherein the small-diameter actuator portion further includes:
a small-diameter connecting rod disposed between the swash plate and the small-diameter actuator piston; and
and a slit groove formed in a part of an outer peripheral surface of the small-diameter actuator piston so as to be recessed in a longitudinal direction of the small-diameter actuator piston, the slit groove communicating a hydraulic pressure of the small-diameter chamber to an inside of the main body.
12. The drive of claim 11, wherein a side of said slot opposite and adjacent to said swash plate is open.
13. The drive of claim 11, wherein the length of the slot is relatively less than the overall length of the small diameter actuator piston.
CN202111401426.4A 2021-08-18 2021-11-19 Actuator piston and driving device comprising same Pending CN115898805A (en)

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Application Number Priority Date Filing Date Title
KR1020210108763A KR102527045B1 (en) 2021-08-18 2021-08-18 Actuator piston and driving device having the same
KR10-2021-0108763 2021-08-18

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CN115898805A true CN115898805A (en) 2023-04-04

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JP2000120541A (en) * 1998-10-19 2000-04-25 Toyota Autom Loom Works Ltd Piston and forming method of groove
KR100429928B1 (en) 2001-05-25 2004-05-03 동명중공업주식회사 Forced Lubricant in Swash Plate for Axial Piston Pump
KR100773988B1 (en) * 2006-06-30 2007-11-08 동명모트롤 주식회사 Swashplate structure of swashplate type axial piston hydraulic pump

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