KR101720880B1 - Hydraulic power unit - Google Patents

Abstract

The present invention relates to a hydraulic power unit, which comprises: a first booster pump raising the pressure of a working fluid supplied from a tank; a second booster pump raising the pressure of a working fluid which is supplied from the tank or the first booster pump to primarily raise the pressure of the working fluid; and a conversion valve interposed between the first booster pump and the second booster pump to control a moving path of the working fluid in accordance with a low load and/or a high load.

Description

[0001] Hydraulic power unit [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power unit used as a power source for operating a hydraulic drive unit.

Generally, a drive source for operating a hydraulic drive apparatus (for example, a hydraulic cylinder) has a structure for generating hydraulic oil through a hydraulic pump connected to an electric motor or a structure for generating hydraulic oil through a booster pump driven by air pressure .

The hydraulic pump directly connected to the electric motor can vary the discharge amount of the hydraulic pump by arbitrarily changing the number of revolutions of the electric motor, while the booster pump (described in Patent Document 1) has a characteristic of changing the discharge amount according to the load If the load is relatively higher than the pressure of the booster pump, the operation of the booster pump can be stopped.

As described above, the booster pump is advantageous in that it is not only excellent in function but also simple in control as compared with a hydraulic pump directly connected to an electric motor, but has a problem in that it is bulky as compared with a hydraulic pump and a pulsation in structure.

Korean Patent No. 10-1339921

It is an object of the present invention to provide a hydraulic power unit having two booster pumps.

Particularly, the present invention is characterized in that two booster pumps are operated as a single stage in a low load state of a hydraulic driving apparatus and two booster pumps are operated in a two stage in a high load state, It is designed to supply.

In order to achieve the above object, the present invention relates to a hydraulic power unit capable of increasing the hydraulic operating oil with two booster pumps,

A first pneumatic operating chamber, a first hydraulic operating chamber arranged coaxially below the first pneumatic operating chamber, a first pump piston moving back and forth inside the first pneumatic operating chamber and the first hydraulic operating chamber, And a first master valve for controlling the flow of the air pressure to be supplied to the inside of the chamber, wherein an eleventh hydraulic pressure passage opened and closed by a first suction check valve and an eleventh hydraulic pressure passage opened and closed by a first discharge check valve A first booster pump forming a hydraulic passage and forming a twelfth hydraulic pressure passage opened and closed by a second suction check valve and a fourteenth hydraulic passage opened and closed by a second discharge check valve in a lower portion of the first hydraulic operation chamber;

A second pneumatic operating chamber, a second hydraulic operating chamber arranged coaxially below the second pneumatic operating chamber, a second pump piston moving forward and backward in the second pneumatic operating chamber and the second hydraulic operating chamber, And a second master valve for controlling the flow of air pressure to be supplied to the inside of the chamber, wherein a second hydraulic pressure passage is provided in the upper portion of the second hydraulic pressure chamber, A second hydraulic pressure passage opened and closed by a second suction check valve and a second hydraulic pressure passage opened and closed by a second discharge check valve are formed at a lower portion of the second hydraulic pressure operating chamber, A second booster pump forming a 26 th hydraulic passage opened and closed by the hydraulic passage and the fourth suction check valve; And

An inlet that is in fluid communication with the thirteenth hydraulic passage and the fourteenth hydraulic passage of the first booster pump, a first outlet that is in fluid communication with the twenty-third hydraulic passage and the twenty-fourth hydraulic passage of the second booster pump, And a switching valve having a twenty-first hydraulic passage of the second booster pump and a second outlet communicating with the twenty-second hydraulic passage in fluid communication therewith.

According to the present invention, the first booster pump is formed by a first pump piston as a first pneumatic operation chamber for backward movement and a first pneumatic operation chamber for forward movement on the upper side, and a first pneumatic operation chamber has a thirteenth pneumatic operation passage And a lower valve rod which is opened and closed by the contact of the first pump piston and has an upper valve rod which is opened and closed by the contact of the first pump piston on the upper side thereof, A seventh pneumatic passage communicating with the thirteenth pneumatic passage; an eleventh pneumatic passage for facilitating mutual communication with the first pneumatic operation chamber; an inner space of the first master valve to an upper valve rod; A seventeenth pneumatic passage communicating with the first master valve; a seventeenth pneumatic passage communicating with the first master valve; a seventeenth pneumatic passage communicating with the first master valve; And is installed on the upper portion of the first pneumatic operating chamber.

Similarly, the second booster pump is formed by a second pump piston as a lower second pneumatic operating chamber for the lower side and a second pneumatic operating chamber for forwarding on the upper side, the second pneumatic operating chamber having a 23rd pneumatic passageway and a 2nd And a lower valve rod which is opened and closed by the contact of the pump piston and has an upper valve rod which is opened and closed by the contact of the second pump piston on the upper side thereof and the second master valve is connected to the forward second pneumatic operating chamber A 24 th pneumatic passage communicating with the 23rd pneumatic passage; a 21 th pneumatic passage that facilitates mutual communication with the 2nd pneumatic operating chamber; a second master valve communicating from the inner space of the second master valve to the upper valve rod A 26 th pneumatic passage, a 27 th pneumatic passage that allows the pneumatic pressure to flow into the internal space of the second master valve, and a second valve spool disposed in the internal space for controlling the flow of the pneumatic pressure It said second is provided on the upper portion of the pneumatic operating chamber.

In particular, the present invention may further comprise an actuator in a piping in fluid communication with the third and fourth hydraulic passages of the second booster pump.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to that, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may properly define the concept of the term in order to best explain its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

According to the present invention as described above, the present invention can provide a hydraulic power unit having two booster pumps.

In the hydraulic power unit according to the present invention, when the load is low, each booster pump can be operated as a single stage to supply a large amount of low-pressure operating oil. On the other hand, when the load is high, the hydraulic oil pressurized by the first booster pump It can be designed as a compact structure that can operate at an additional boosted two stage to increase the efficiency while providing a high booster ratio.

At the same time, the present invention can achieve an energy saving effect by operating the air pressure according to a low load and a high load, and consuming only an appropriate amount of energy.

Further, the present invention can alleviate the pressure pulsation phenomenon.

1 is a schematic view showing a hydraulic power unit according to a preferred embodiment of the present invention.
FIG. 1A is a view illustrating a hydraulic power unit according to a preferred embodiment of the present invention employing another type of switching valve. FIG.
2 is a schematic view illustrating a hydraulic power unit according to a preferred embodiment of the present invention when the load is high.
FIG. 2A illustrates another type of switching valve incorporated in a hydraulic power unit according to a preferred embodiment of the present invention.

The hydraulic power unit according to the present invention will now be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages, features, and ways of accomplishing the same will become apparent from the following description of embodiments taken in conjunction with the accompanying drawings. In the specification, the same reference numerals denote the same or similar components throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The hydraulic power unit 1 according to the preferred embodiment of the present invention has the following configuration.

Referring to the drawings, a hydraulic power unit 1 according to a preferred embodiment of the present invention includes a first booster pump 100, a second booster pump 200, a first booster pump 100, A switching valve 300 provided in fluid communication with the main body 200, and an accumulator 400.

The first booster pump 100 forms the first pneumatic operation chamber 110 and the first hydraulic operation chamber 120. [ The first booster pump 100 disposes the first pump piston P1 in the internal space defined by the first pneumatic operation chamber 110 and the first hydraulic operation chamber 120, Is arranged coaxially on the lower side of the first pneumatic operating chamber (110).

The first pump piston P1 comprises a piston head P1-1, a piston rod P1-2 and a piston ring P1-3.

The first pneumatic operation chamber 110 is connected to the first pneumatic operation chamber 110a for backward movement by the piston head P1-1 of the first pump piston P1 and the first pneumatic operation chamber 110b for forward movement ) Can be formed. That is, the thirteenth pneumatic passage H13 communicates with the first pneumatic operation chamber 110a for backward movement, and the fifteenth pneumatic passage H15 communicates with the first pneumatic operation chamber 110b for advancement.

The first pump piston P1 disposes the piston rod P1-2 extending downward to the first pneumatic actuating chamber 110 and the first hydraulic actuating chamber 120.

The piston ring P1-3 is provided on the outer peripheral surface of the piston rod P1-2. Preferably, the piston ring P1-3 is slidably disposed between the thirteenth hydraulic passage W13 and the fourteenth hydraulic passage W14. The first hydraulic operation chamber 120 may be formed by a piston ring P1-3 to form a first hydraulic operation chamber 120a for moving backward and a forward first hydraulic operation chamber 120b .

In particular, the upper end of the first booster pump 100 has a first master valve 150 that allows the flow of air pressure to be injected and / or discharged to the first pneumatic operating chamber 110. The first master valve 150 is connected to the eleventh pneumatic passage H11 and the fourteenth pneumatic passage H14, the fifteenth pneumatic passage H15 and the sixteenth pneumatic passage H14 by means of the first valve spool 160, The passage H16, and the seventeenth pneumatic passage H17 in order to control the flow of the air pressure. The first master valve 150 also has an upper valve rod 170 disposed on the upper side of the first pneumatic chamber 110 and opened by pressurization in response to the backward movement of the first pump piston P1, The first pneumatic operation chamber 110 is interposed between the eleventh pneumatic passage H11, the sixteenth pneumatic passage H16 and the first pneumatic operation chamber 110. [ The upper valve rod 170 is provided with a pressure spring 171 at the upper end thereof for pneumatic pressure to flow into the eleventh pneumatic passage H11, pneumatic pressure to flow through the sixteenth pneumatic passage H16, It is possible to communicate or close the eleventh pneumatic passage H11 and the sixteenth pneumatic passage H16 with each other. In addition, the first booster pump 100 has a lower valve rod 180 disposed below the first pneumatic operating chamber 110 and opened to pressurization in accordance with the forward driving of the first pump piston P1, The lower valve rod 180 is interposed between the twelfth pneumatic passage H12, the eighteenth pneumatic exhaust passage H18 and the lower side of the first pneumatic operation chamber 110. [ The lower valve rod 180 is attached to the lower end of the lower valve rod 180 with a pressure spring 181 to pressurize the pneumatic pressure flowing into the 12th pneumatic passage H12 and / Can be opened and closed.

Specifically, the first booster pump 100 is connected to the first master valve 150 so that the first master valve 150 and the first pneumatic operation chamber 110a for backward movement of the first pneumatic operation chamber 110 are in fluid communication with each other, And a thirteenth pneumatic passage H13 is formed on the lower side of the first pneumatic operation chamber 110. [ The first master valve 150 can be supplied with air pressure through the seventeenth pneumatic passage H17 to the inner space.

The fifteenth air pressure passage H15 is formed so that the inner space of the first master valve 150 and the first pneumatic operation chamber 110b for advancement of the first pneumatic operation chamber 110 can communicate with each other.

The pneumatic pressure introduced into the seventeenth pneumatic passage H17 moves the first valve spool 160 of the first master valve 150 to pass through the fifteenth pneumatic passage H15 to the first pneumatic operation chamber 110, , In particular, into the first forward pneumatic operating chamber 110b. The pneumatic pressure introduced into the first pneumatic operation chamber 110b for advancing the first pneumatic operation chamber 110 advances the pump piston P1 as a result.

At this time, the air pressure in the first pneumatic operation chamber 110a is exhausted to the outside through the thirteenth pneumatic passage H13, the fourteenth pneumatic passage H14, and the first valve spool 160. At this time,

The pneumatic pressure introduced into the seventeenth pneumatic passage H17 moves the first valve spool 160 of the first master valve 150 to pass through the fourteenth pneumatic passage H14 and the thirteenth pneumatic passage H13 And flows into the first pneumatic operation chamber 110a for backward movement of the first pneumatic operation chamber 110. [ The air pressure introduced into the first pneumatic operating chamber 110a for backward movement of the first pneumatic operating chamber 110 causes the pump piston P1 to move backward.

The first booster pump 100 is provided with an eleventh hydraulic pressure passage W11 and a thirteenth hydraulic pressure passage W13 for ensuring the flow of hydraulic oil to and from the first hydraulic operating chamber 120b for reverse movement of the first hydraulic pressure operating chamber 120 And a twelfth hydraulic pressure passage W12 and a fourteenth hydraulic pressure passage W14 are formed in the first hydraulic operation chamber 120a of the first hydraulic operation chamber 120 to ensure the flow of hydraulic fluid.

The first booster pump 100 is provided with the first suction check valve 121 in the eleventh hydraulic pressure passage W11 so as to open and close the tank T and the forward first hydraulic operation chamber 120b in fluid communication . The first booster pump 100 can control the hydraulic oil in the forward first hydraulic operation chamber 120b to be able to be transferred to the rear end facility by disposing the first discharge check valve 123 in the thirteenth hydraulic pressure passage W13 Can be opened and closed. The eleventh hydraulic pressure passage W11 and the thirteenth hydraulic pressure passage W13 may be arranged at the same height (or level).

The first booster pump 100 is provided with a second suction check valve 122 in the twelfth hydraulic pressure passage W12 so that the tank T and the first hydraulic operation chamber 120a for backward movement can be in fluid communication with each other Can be opened and closed. The first booster pump 100 can control the hydraulic oil in the first hydraulic operating chamber 120a to be transferred to the rear end facility by disposing the second discharge check valve 124 in the fourteenth hydraulic passage W14 Can be opened and closed. The twelfth hydraulic pressure passage W12 and the fourteenth hydraulic pressure passage W14 may be arranged at the same height (or level).

The arrangement is such that the eleventh hydraulic pressure passage W11 and the thirteenth hydraulic pressure passage W13 are disposed higher than the upper dead point corresponding to the position when the piston ring P1-3 is located at the uppermost position of the piston ring P1-3, The lower oil pressure passage W12 and the fourteenth oil pressure passage W14 are disposed lower than the bottom dead center point corresponding to the position when the oil pressure is lowered to the lowermost portion of the oil pressure passage.

The second booster pump 200 is disposed in parallel with or adjacent to the first booster pump 100 so as to be in fluid communication with the second booster pump 200. The second booster pump 200 forms the second pneumatic operation chamber 210 and the second hydraulic operation chamber 220 do. The second booster pump 200 disposes the second pump piston P2 in the internal space defined by the second pneumatic operation chamber 210 and the second hydraulic operation chamber 220, Is arranged coaxially on the lower side of the second pneumatic operating chamber (210).

 The second pump piston P2 is composed of the piston head P2-1, the piston rod P2-2 and the piston ring P2-3.

The second pneumatic operation chamber 210 is connected to the second pneumatic operation chamber 210a for backward movement by the piston head P2-1 of the second pump piston P2 and the second pneumatic operation chamber 210b for forward movement ) Can be formed. That is, the 23rd pneumatic passage H23 is communicated with the second pneumatic operation chamber 210a for backward movement and the 25th pneumatic passage H25 is communicated with the second pneumatic operation chamber 210b for advancement.

The second pump piston P2 is extended downward to arrange the piston rod P2-2 across the second pneumatic operation chamber 210 and the second hydraulic operation chamber 220. [

The piston ring P2-3 is provided on the outer peripheral surface of the piston rod P2-2. Preferably, the piston ring P2-3 is slidably disposed between the 23rd hydraulic passage W23 and the 24th hydraulic passage W24. The second hydraulic operation chamber 220 can be formed with the second hydraulic operation chamber 220a for the reverse movement at the lower portion by the piston ring P2-3 and the second hydraulic operation chamber 220b for forward movement formed at the upper portion thereof .

In particular, the upper end of the second booster pump 200 has a second master valve 250 that allows the flow of air pressure to be injected and / or discharged to the second pneumatic operating chamber 210. The second master valve 250 is provided with a 21st pneumatic passage H21 and a 24th pneumatic passage H24, a 25th pneumatic passage H25 and a 26th pneumatic passage H24 by means of a second valve spool 260 in the interior thereof. The passage H26, and the 27th pneumatic passage H27, so as to control the flow of the air pressure. The second master valve 250 also has an upper valve rod 270 which is disposed on the upper side of the second pneumatic operating chamber 210 and opens to the pressure due to the backward driving of the second pump piston P2, The rod 270 is interposed between the twenty-first pneumatic passage H21, the twenty-sixth pneumatic passage H26, and the second pneumatic actuating chamber 210. [ The upper valve rod 270 is provided with a pressure spring 271 at the upper end thereof for pneumatic pressure to flow into the twenty-first pneumatic passage H21, pneumatic pressure to flow through the twenty-sixth pneumatic passage H26, The twenty-first pneumatic passage H21 and the twenty-sixth pneumatic passage H26 can be communicated with each other or closed. In addition, the second booster pump 200 has a lower valve rod 280 disposed below the second pneumatic operating chamber 210 and opened by pressurization in accordance with the forward driving of the second pump piston P2, The lower valve rod 280 is interposed between the 22nd pneumatic passage H22, the 28th pneumatic exhaust passage H28 and the lower side of the second pneumatic operation chamber 210. [ The lower valve rod 280 is attached to the lower end of the lower valve rod 280 with a pressure spring 281 and pressurized by the pneumatic pressure flowing into the 22nd pneumatic passage H22 and / Can be opened and closed.

Specifically, the second booster pump 200 is connected to the second master valve 250 so that the second master valve 250 and the second pneumatic operation chamber 210a of the second pneumatic operation chamber 210 are in fluid communication with each other, And a 23rd pneumatic passage H23 is formed on the lower side of the second pneumatic operation chamber 210. [ And the second master valve 250 can be supplied with air pressure through the 27th pneumatic passage H27 into the inner space.

The twenty-fifth pneumatic passage H25 is formed so that the inner space of the second master valve 250 and the second pneumatic operation chamber 210b for advance of the second pneumatic operation chamber 210 can communicate with each other.

The pneumatic pressure introduced into the 27th pneumatic passage H27 moves the second valve spool 260 of the second master valve 250 to pass through the 25th pneumatic passage H25 to the second pneumatic operation chamber 210, , In particular, into the second pneumatic operation chamber 210b for forward movement. The pneumatic pressure introduced into the second pneumatic operating chamber 210b for advancement of the second pneumatic operating chamber 210 results in advancing the pump piston P2.

At this time, the air pressure in the second pneumatic operation chamber 210a is exhausted to the outside through the 23rd pneumatic passage H23, the 24th pneumatic passage H24, and the 2nd valve spool 260. [

The pneumatic pressure introduced into the 27th pneumatic passage H27 moves the second valve spool 260 of the second master valve 250 to pass through the 24th pneumatic passage H24 and the 23rd pneumatic passage H23 And then flows into the second pneumatic operation chamber 210a for backward movement of the second pneumatic operation chamber 210. The pneumatic pressure introduced into the second pneumatic operation chamber 210a of the second pneumatic operation chamber 210 causes the pump piston P2 to move backward.

The second booster pump 200 includes a twenty-first hydraulic pressure passage W21 and a twenty-third hydraulic pressure passage W23 for ensuring the flow of hydraulic oil to and from the first hydraulic operating chamber 220b for reverse movement of the second hydraulic pressure operating chamber 220, And a twenty-second hydraulic pressure passage W22 and a twenty-fourth hydraulic pressure passage W2 for ensuring the flow of hydraulic oil into the first hydraulic operating chamber 220a for forward movement of the second hydraulic pressure operating chamber 220, W24 and the 26th hydraulic pressure passage W26.

The second booster pump 200 is arranged such that the first suction check valve 221 is disposed in the 21st hydraulic pressure passage W21 and the third suction check valve 225 is disposed in the 25th hydraulic pressure passage W25, Or the switching valve 300 and the forward second hydraulic operating chamber 220b in fluid communication with each other. The second booster pump 200 can control the hydraulic oil in the forward second hydraulic pressure operating chamber 220b to be able to be transferred to the rear end facility by disposing the first discharge check valve 223 in the 23rd oil pressure passage W23 Can be opened and closed. The twenty-first hydraulic pressure passage W21 and the twenty-third hydraulic pressure passage W23 may be arranged at the same height (or level), and the twenty-fifth hydraulic pressure passage W25 may be arranged at a position higher than the twenty-first hydraulic pressure passage W21 Lt; / RTI >

The second booster pump 200 is provided with the second suction check valve 222 in the 22nd oil pressure passage W22 and the fourth suction check valve 226 in the 26th oil pressure passage W26, (T) or the switching valve (300) and the second hydraulic operation chamber (220a) for reverse movement in fluid communication. The second booster pump 200 can arrange the second discharge check valve 224 in the 24th hydraulic pressure passage W24 so as to control the hydraulic fluid in the second hydraulic operating chamber 220a to be transferred to the rear stage equipment Can be opened and closed. The twenty-second hydraulic pressure passage W22 and the twenty-fourth hydraulic pressure passage W24 may be arranged at the same height (or level), and the twenty-sixth hydraulic pressure passage W26 may be arranged below the twenty- Lt; / RTI >

The arrangement is such that the 21st hydraulic pressure passage W21, the 23rd hydraulic pressure passage W23 and the 25th hydraulic pressure passage W25 are arranged higher than the top dead center point at the position when the piston ring P2-3 is located at the uppermost position of the piston ring P2-3 The twenty-second hydraulic pressure passage W22, the twenty-fourth hydraulic pressure passage W24 and the twenty-sixth hydraulic pressure passage W26 are disposed lower than the bottom dead point corresponding to the position when the piston ring P2-3 is lowered to the lowermost portion of the piston ring P2-3 .

The hydraulic power unit 1 according to the present invention includes the first booster pump 100 and the second booster pump 200 via the switching valve 300 between the first booster pump 100 and the second booster pump 200, The second booster pump 200 can be controlled to be in fluid communication.

The switching valve 300 includes an inlet 310, a first outlet 320 and a second outlet 330. The operating fluid pressurized from the first booster pump 100 flows into the inlet 310, The hydraulic oil can be selectively switched to the hydraulic cylinder 500 or the second booster pump 200 in response to a low or high load of the hydraulic power unit 1 according to the preferred embodiment of the present invention.

The switching valve 300 can be employed as the electronic switching valve 300 shown in Figs. 1 and 2 or the pilot switching valve 300 shown in Figs. 1A and 2A, including, but not limited to, Valves can also be substituted.

In addition, the hydraulic power unit 1 according to the present invention may further include an aligner 400 to mitigate the ripple phenomenon. The accumulator 400 may be disposed downstream of the third hydraulic passage W23 and the fourth hydraulic passage W24 of the second booster pump 200 as shown.

Hereinafter, the driving of the hydraulic power unit according to the preferred embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a view showing the operating position of the switching valve of the hydraulic power unit 1 according to the preferred embodiment of the present invention when the load is low.

The piping (not shown) of the tank T is extended to the eleventh hydraulic pressure passage W11 and the twelfth hydraulic pressure passage W12 of the first booster pump 100 and the second booster pump 100 25 hydraulic pressure passage W25 and the 26th hydraulic pressure passage W26.

The first suction check valve 121 is provided in the eleventh hydraulic pressure passage W11 so as to control the flow of hydraulic oil to be supplied from the tank T to the eleventh hydraulic pressure passage W11, The two suction check valves 122 may be provided in the twelfth hydraulic pressure passage W12 so as to control the flow of hydraulic oil to be supplied from the tank T to the twelfth hydraulic pressure passage W12.

Similarly, the third suction check valve 225 is provided in the 25th hydraulic pressure passage W25 so as to control the flow of the hydraulic oil to be supplied from the tank T to the 25th hydraulic pressure passage W25, The check valve 226 may be provided in the 26th hydraulic pressure passage W26 so as to control the flow of the hydraulic oil to be supplied from the tank T to the 26th hydraulic pressure passage W26.

The inlet 310 of the switching valve 300 is connected to the first booster pump 100 via the first booster pump 100 having the thirteenth hydraulic pressure passage W13 provided with the first discharge check valve 123 and the second discharge check valve 124 provided with the second discharge check valve 124. [ 14 hydraulic fluid passage W14.

The pipe extended from the first outlet 320 of the switching valve 300 is connected to the 23rd hydraulic pressure passage W23 provided with the first discharge check valve 223 of the second booster pump 200, The second outlet port 330 of the switching valve 300 is connected to the first suction check valve (not shown) of the second booster pump 200 And a twenty-second hydraulic pressure passage W22 provided with a second suction check valve 222 and a second hydraulic pressure passage W21 provided with a second suction pressure check valve 222. [

As shown in the figure, the 23rd and 24th hydraulic passages W23 and W24 of the second booster pump 200 are piped so as to be in fluid communication with the hydraulic cylinder 500.

The hydraulic power unit 1 according to the present invention operates the first booster pump 100 and the second booster pump 200 individually at the time of low load. In this process, the hydraulic oil stored in the tank T is supplied to the first And flows into the eleventh hydraulic pressure passage W11 and the twelfth hydraulic pressure passage W12 of the boost pump 100, respectively. The operating fluid in the first booster pump 100 then flows through the thirteenth and fourteenth hydraulic passages W13 and W14 into the inlet 310 of the switching valve 300 and flows through the first outlet 320, .

At the same time, the second booster pump 200 is supplied with the working oil supplied from the tank T through the twenty-fifth hydraulic pressure passage W25 and the twenty-sixth hydraulic pressure passage W26, thereby increasing the pressure. Subsequently, the hydraulic fluid pressurized in the second booster pump 200 is discharged to the 23rd and 24th hydraulic passages W23 and W24, and the hydraulic fluid in the second booster pump 200, which is combined with the hydraulic fluid pressurized by the first booster pump 100, And is supplied to the hydraulic drive apparatus, that is, the hydraulic cylinder 500.

Fig. 2 is a view showing the operating position of the switching valve of the hydraulic power unit 1 according to the preferred embodiment of the present invention when the load is high.

The operating fluid pressurized in the first booster pump 100 flows into the inlet port 310 of the switching valve 300 through the thirteenth and fourteenth hydraulic passages W13 and W14 of the first booster pump 100, And is guided to the second booster pump (200) through the second outlet (330).

The first boosted hydraulic oil from the first booster pump 100 is supplied to the second booster pump 200 through the second and third hydraulic passages W21 and W22 of the second booster pump 200, And flows into the hydraulic operating chamber 220. The operating oil supplied from the first booster pump 100 is secondarily pressurized and discharged to the 23rd and 24th hydraulic passages W23 and W24 of the second booster pump 200 through the operation of the second booster pump 200. [ The high-pressure hydraulic fluid is supplied to the hydraulic drive apparatus disposed downstream, that is, to the hydraulic cylinder 500.

The suction check valve of the second booster pump 200 will not be able to temporarily flow the hydraulic fluid due to the back pressure in the second booster pump while the second booster pump 220 discharges the second boosted hydraulic fluid.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It is obvious that the modification and the modification can be made by the person having.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1 ----- Hydraulic power unit,
100 ----- First booster pump,
110 ----- First pneumatic operating chamber,
120 ----- First hydraulic operating chamber,
150 ----- first master valve,
200 ----- Second booster pump,
210 ----- Second pneumatic operating chamber,
220 ----- Second hydraulic operating chamber,
250 ---- Second master valve,
300 ----- Switching valve,
400 ----- Accelerator,
500 ----- Hydraulic cylinder,
P1, P2 ----- Pump piston.

Claims (9)

A first pneumatic operation chamber 110 and a first hydraulic operation chamber 120 arranged coaxially on the lower side of the first pneumatic operation chamber 110. The first pneumatic operation chamber 110 and the first hydraulic operation chamber A first pump piston P1 moving forward and rearward in the chamber 120 and a first master valve 150 controlling the flow of pneumatic pressure to be supplied into the first pneumatic operation chamber 110, An eleventh hydraulic pressure passage W11 opened and closed by the first suction check valve 121 and a thirteenth hydraulic pressure passage W13 opened and closed by the first discharge check valve 123 are formed on the upper portion of the hydraulic operating chamber 120 A twelfth hydraulic pressure passage W12 opened and closed by a second suction check valve 122 and a fourteenth hydraulic pressure passage W14 opened and closed by a second discharge check valve 124 in a lower portion of the first hydraulic pressure operating chamber 120, A first booster pump 100 which forms a first booster pump 100;
A second hydraulic operating chamber 220 arranged coaxially on the lower side of the second pneumatic operating chamber 210, a second hydraulic operating chamber 210 connected to the second pneumatic operating chamber 210, A second pump piston (P2) moving forward and rearward in the chamber (220), and a second master valve (250) controlling the flow of air pressure to be supplied into the second pneumatic operation chamber (210) A second hydraulic pressure passage W21 opened and closed by a first suction check valve 221 and a 23rd hydraulic pressure passage W23 opened and closed by a first discharge check valve 223 and a third hydraulic pressure passage W23 opened and closed by a first discharge check valve 223, A twenty-fifth hydraulic pressure passage W22 opened and closed by a suction check valve 225 and a twenty-second hydraulic pressure passage W22 opened and closed by a second suction check valve 222 below the second hydraulic pressure operation chamber 220, A second booster pump 200 for forming a twenty-fourth hydraulic pressure passage W24 opened and closed by the second discharge check valve 224 and a twenty-sixth hydraulic pressure passage W26 opened and closed by the fourth suction check valve 226; And
An inlet 310 connected in fluid communication with the thirteenth hydraulic pressure passage W13 and the fourteenth hydraulic pressure passage W14 of the first booster pump 100, A first outlet 320 connected in fluid communication with the passage W23 and the 24th hydraulic pressure passage W24 and a first outlet 322 connected to the 21st hydraulic pressure passage W21 and the 22nd hydraulic pressure passage W24 of the second booster pump 200, And a second outlet (330) connected in fluid communication with the second outlet (330).
The method according to claim 1,
The first booster pump 100 is formed by the first pump piston P1 as a first pneumatic operation chamber 110a for backward movement and a first pneumatic operation chamber 110b for forward movement on the upper side,
The first pneumatic operation chamber 110 is provided with a thirteenth pneumatic passage H13 at a lower portion thereof and a lower valve rod 180 opened and closed by the contact of the first pump piston P1, And an upper valve rod 170 which is opened and closed by the contact of the piston P1,
The first master valve 150 includes a fifteenth pneumatic passage H15 communicating with the forward first pneumatic operation chamber 110b through the upper valve rod 170 and a thirteenth pneumatic passageway H15 communicating with the thirteenth pneumatic passageway H13 An eleventh pneumatic passage H11 for facilitating mutual communication with the first pneumatic operation chamber 110 and an eleventh pneumatic passage H11 for communicating with the upper valve rod 170 in the inner space of the first master valve 150. [ And a seventeenth pneumatic passage H17 for allowing the inflow of air pressure into the internal space of the first master valve 150 is formed in the inner space of the first master valve 150, And a first valve spool (160) for controlling the first valve operating member (110).
The method according to claim 1,
The second booster pump 200 is formed by the second pump piston P2 as a second pneumatic operation chamber 210a for forward movement and a second pneumatic operation chamber 210b for forward movement on the upper side,
The second pneumatic operation chamber 210 is provided at its lower portion with a 23rd pneumatic passage H23 and a lower valve rod 280 which is opened and closed by the contact of the second pump piston P2, And an upper valve rod 270 which is opened and closed by the contact of the piston P2,
The second master valve 250 includes a 25th pneumatic passage H25 communicating with the forward second pneumatic operation chamber 210b through the upper valve rod 270 and a 25th pneumatic passage H25 communicating with the 23rd pneumatic passage H23 A second pneumatic passage H21 for facilitating mutual communication with the second pneumatic operation chamber 210 and a second pneumatic passage H21 for communicating with the upper valve rod 270 in the inner space of the second master valve 250. [ A second pneumatic passage H26 communicating with the second master valve 250 to the inner space of the second master valve 250 and a 27th pneumatic passage H27 allowing the inflow of air pressure into the inner space of the second master valve 250, And a second valve spool (260) for controlling the second valve operating chamber (210).
The method according to claim 1,
Further comprising an actuator (400) in a piping in fluid communication with the third hydraulic passage (W23) and the fourth hydraulic passage (W24) of the second booster pump (200).
The method according to claim 1,
The first pump piston P1 comprises a piston head P1-1, a piston rod P1-2 and a piston ring P1-3,
Wherein the second pump piston (P2) comprises a piston head (P2-1), a piston rod (P2-2) and a piston ring (P2-3).
The method of claim 5,
The piston ring P1-3 is disposed between the thirteenth hydraulic passage W13 and the fourteenth hydraulic passage W14,
The piston ring (P2-3) is disposed between the 23rd hydraulic passage (W23) and the 24th hydraulic passage (W24).
The method of claim 2,
The first booster pump 100 includes a pressing spring 171 at the upper end of the upper valve rod 170 and a pressing spring 181 at the lower end of the lower valve rod 180,
The first booster pump 100 includes a twelfth pneumatic passage H12 for supplying pneumatic pressure to the lower valve rod 180 and a seventeenth pneumatic passage H18 for pneumatic exhausting through the lower valve rod 180 A hydraulic power unit.
The method of claim 3,
The second booster pump 200 includes a pressing spring 271 at the upper end of the upper valve rod 270 and a pressing spring 281 at the lower end of the lower valve rod 280,
The second booster pump 200 includes a 22nd pneumatic passage H22 for supplying pneumatic pressure to the lower valve rod 280 and a 28th pneumatic passage H28 for exhausting pneumatic pressure through the lower valve rod 280 A hydraulic power unit.
The method according to claim 1,
The switching valve (300) comprises an electromagnetic switching valve or a pilot operation switching valve.

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