KR101655458B1 - Valve for controlling hydraulic pump of construction machinery - Google Patents

Abstract

The hydraulic pump control valve of the construction machine according to the present invention distributes the pressure of the plurality of center bypass lines 14a and 14b to each of the regulators 20a and 20b provided in each of the hydraulic pumps 10a and 10b And includes a valve body (31); First and second inlet ports 32a and 32b formed in the valve body 31 and connected to the first and second center bypass lines 14a and 14b, respectively; First and second discharge ports 33a and 33b provided on the valve body 31 and connected to the regulators 20a and 20b, respectively; A third discharge port 33c provided on the valve body 31 and connected to the tank T; And a spool (35) movably installed between the first position and the second position on the valve body (31), wherein the first and second grooves (35a, 35b) are spaced apart from each other, Each of the first and second inlet ports 32a and 32b is connected to the third outlet port 33c through the first and second grooves 35a and 35b, When the spool 35 moves to the second position, the first and second inlet ports 32a and 32b are connected to the first and second outlet ports 33a and 33b, respectively, Respectively.

Construction machinery, children, fuel economy improvement, valve number, manufacturing cost, miniaturization

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a valve for controlling a hydraulic pump of a construction machine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction machine such as an excavator, and more particularly to a hydraulic pump control valve of a construction machine for selecting one of a pressure of a center bypass line and a pilot pressure as a signal pressure for controlling a hydraulic pump of a construction machine will be.

Generally, a construction machine such as an excavator is provided with a plurality of actuators for driving or driving various working devices, and the plurality of actuators are driven by hydraulic oil discharged from a variable displacement hydraulic pump driven by an engine or an electric motor .

The flow rate of the hydraulic fluid discharged from the variable displacement hydraulic pump is controlled according to the workload so as to minimize the power loss, and one example is shown in FIG.

Referring to FIG. 1, the swash plate angle is adjusted in accordance with the signal pressure inputted to each regulator 2, so that the discharge flow rate is adjusted by a pair of hydraulic pumps 1 driven directly to the engine. The signal pressure inputted to the regulator 2 is drawn out from the center bypass line 6 passing through the plurality of control valves 3 and the relief valve 4 and the orifice 5 ) Are connected in parallel with each other.

First, when the operation signal of the operation unit such as the joystick is not inputted, the plurality of control valves 3 are placed in the neutral state. In this state, the hydraulic fluid discharged from the hydraulic pump 1 is discharged to the tank T through the center bypass line 6. [ At this time, the flow rate of the hydraulic fluid drained to the tank T is limited by the orifice 5, so that the pressure of the center bypass line 6 rises to the relief pressure of the relief valve 4, The swash plate angle of the hydraulic pump 1 is adjusted so that the flow rate of the hydraulic pump 1 is reduced.

On the other hand, when an operation signal is inputted from the operation unit, any one of the plurality of control valves 3 is converted, whereby the flow rate of the hydraulic oil flowing through the center bypass line 6 is reduced. Then, the amplitude of the signal pressure input to the regulator 2 is reduced, whereby the swash plate angle of the hydraulic pump 1 is adjusted in the direction in which the flow rate of the hydraulic pump 1 increases.

According to the hydraulic pump control device as described above, even when the working device or the traveling device is not driven, the hydraulic pressure of the hydraulic pump 1 can be increased so that the working oil of the center bypass line 6 can reach the relief pressure of the relief valve 4. [ Must discharge a constant flow rate. That is, even when the plurality of control valves 3 are all in the neutral state, the hydraulic pump 1 must be driven so as to be able to supply a constant flow rate, resulting in power loss of the engine.

Since the hydraulic oil discharged from the hydraulic pump 1 is drained to the drain tank T through the orifice 5 and the relief valve 4, a pressure loss is generated, whereby the loss of power of the engine E And the temperature of the operating oil is increased. When the temperature of the operating oil rises, the driving precision of each actuator is lowered, and the expensive hydraulic parts are damaged and the service life is shortened, thereby decreasing the reliability of the construction machine.

In order to solve such a problem, in recent years, when the construction machine is in the idle state, the pilot pressure of the gear pump is adopted as the signal pressure to be transmitted to the regulator 2 and the operating oil of the center bypass line 6 is supplied to the tank T Research is underway to minimize power loss by discharging. However, in order to implement the above-described hydraulic pump control device, a pair of intermittent valves for discharging each of the center bypass lines 6 to the tank T is required. Further, a pair of selection valves such as a shuttle valve for selecting the signal pressure among the center bypass line 6 and the pilot pressure of the gear pump is also required.

That is, in order to minimize the loss of power as described above, a lot of hydraulic parts must be additionally installed, which raises the manufacturing cost. Here, the above-described technique for minimizing power loss is not a known technique.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve for controlling a hydraulic pump of a construction machine capable of minimizing the number of parts to be added while minimizing power loss of a construction machine, .

In order to achieve the above object, a valve for controlling a hydraulic pump of a construction machine according to the present invention is characterized in that a pressure of a plurality of center bypass lines (14a, 14b) is regulated by a regulator (10a, 10b) provided in each of a plurality of hydraulic pumps (20a) and (20b), respectively, and includes a valve body (31); First and second inlet ports 32a and 32b formed in the valve body 31 and connected to the first and second center bypass lines 14a and 14b, respectively; First and second discharge ports 33a and 33b provided on the valve body 31 and connected to the regulators 20a and 20b, respectively; A third discharge port 33c provided on the valve body 31 and connected to the tank T; And a spool (35) movably installed between the first position and the second position on the valve body (31), wherein the first and second grooves (35a, 35b) are spaced apart from each other, Each of the first and second inlet ports 32a and 32b is connected to the third outlet port 33c through the first and second grooves 35a and 35b, When the spool 35 moves to the second position, the first and second inlet ports 32a and 32b are connected to the first and second outlet ports 33a and 33b, respectively, Respectively.

According to an embodiment of the present invention, the hydraulic pump control valve includes a pressure receiving portion 34 provided on the valve body 31 and connected to the pilot line 13 of the gear pump 12; And a pilot passage (36) provided in at least one of the valve body (31) and the spool (35) so as to communicate with the pressure receiving portion (34), wherein a pilot pressure of the gear pump (12) (34), the spool (35) is moved to the first position to communicate the pressure receiving portion (34) and the first discharge port (33a), and the pilot passage (36) And communicates with the port 33b.

In addition, the pilot passage 36 includes a first passage 36a formed in the spool 35 in the longitudinal direction thereof; And a second passage (36b) formed to extend to an outer circumferential surface of the spool (35) in a radial direction of the spool (35) so as to communicate with the first passage (36a), and the second passage (36b) And is formed in the third groove 35c formed between the first and second grooves 35a and 35b.

According to the above-mentioned problem, when the spool is in the first position, the first and second inlet ports are connected to one third discharge port, and when the spool is in the second position, each of the first and second inlet ports By forming the first and second grooves in the spool to be connected to the first and second discharge ports, a pair of center bypass lines can be connected to the tank or respectively to the pair of regulators without additional valve addition, As a result, the number of parts can be minimized while improving the fuel efficiency of the construction machine, thereby reducing manufacturing costs.

Further, by forming a pilot passage communicating with the hydraulic pressure portion of the gear pump and the hydraulic pressure portion and communicating the hydraulic pressure portion with the first discharge port and the pilot passage with the second discharge port according to the position of the spool, Pilot pressure can be delivered to the regulator, further minimizing the number of valves.

Further, the size of the hydraulic pump control valve can be minimized by forming the pilot passage in the spool and forming the third groove communicating with the pilot passage on the spool.

Hereinafter, a valve for controlling a hydraulic pump of a construction machine according to an embodiment of the present invention will be described in detail.

2 is a schematic view of a hydraulic circuit diagram to which a hydraulic pump control valve 30 according to an embodiment of the present invention is applied.

2, the center bypass line 14a and 14b and the pilot line 13 are connected to one side of the hydraulic pump control valve 30 and the tank T and the first and second regulators (20a) and (20b) are connected. On the other hand, the pilot line 13 is connected to the pressure receiving portion 34 of the hydraulic pump control valve 30.

When the hydraulic pump control valve 30 is changed to the state shown in FIG. 2 (hereinafter referred to as a "second position"), the pressure of the center bypass line 14a (14b) Regulators 20a and 20b. On the other hand, when the hydraulic pump control valve 30 is changed to the opposite state to that of FIG. 2 (hereinafter referred to as a "first position"), the center bypass line 14a, 14b is connected to the tank T, The pressure of the pilot line 13 is transmitted to the first and second regulators 20a and 20b. The pilot line 13 is connected to the gear pump 12 by a directional switching valve 15 or to a tank T. [

On the other hand, a valve signal line 16 is connected to the pressure receiving portion of the directional control valve 15. The valve signal line 16 includes a first valve signal line 16a whose signal pressure varies in accordance with the change of the travel control valve 11a among the plurality of control valves 11a and 11b, The first valve signal line 16a and the second valve signal line 16b are connected in parallel to each other so that the signal pressure is varied according to the change of the control valve 11b other than the first valve signal line 16a and the second valve signal line 16b, And a third valve signal line 16c for selectively applying the signal to the pressure receiving portion of the directional control valve 15 as a signal pressure. The pressure of the third valve signal line 16c varies depending on whether the plurality of control valves 11 are converted or not.

That is, when the plurality of control valves 11a and 11b are in the neutral state (the idle state of the construction machine), the first and second valve signal lines 16a and 16b pass through the respective logic valves 17 Drain line, the pressure of the third valve signal line 16c is lowered. Thereby, the directional switching valve 15 is changed in the opposite direction as shown in Fig. 2 to transmit the pilot hydraulic fluid of the gear pump 12 to the hydraulic pump control valve 30. Fig. 2 so as to connect the center bypass lines 14a and 14b to the tank T and to apply the pressure of the pilot line 13 to the first and second regulators (20a) and (20b).

On the other hand, when any one of the plurality of control valves 11a and 11b is shifted out of the neutral state (the working state of the construction machine), the logic valve 17 is turned to the first and second valve signal lines 16a ) 16b. As a result, the pressure of the third valve signal line 16c is increased. Thereby, the direction switching valve 15 is converted into a state as shown in Fig. 2 and connects the pilot line 13 of the hydraulic pump control valve 30 to the tank T. Thereby, the hydraulic pump control valve 30 connects the center bypass lines 14a and 14b to the first and second regulators 20a and 20b.

The hydraulic pump control valve 30 drains the hydraulic fluid of the center bypass lines 14a and 14b to the tank T when the construction machine is idle and supplies the pressure of the pilot line 13 to the regulator 20a ) 20b. On the other hand, when the construction machine is in the working state, the hydraulic pump control valve 30 connects the center bypass lines 14a and 14b to the regulators 20a and 20b.

Hereinafter, the structure of the hydraulic pump control valve 30 functioning as described above will be described in detail.

3 to 5, a valve 30 for controlling a hydraulic pump according to an embodiment of the present invention includes a valve body 31, a valve body 31 formed on the valve body 31, First and second inlet ports 32a and 32b connected to the respective lines 14a and 14b and first and second inlet ports 32a and 32b provided in the valve body 31 and connected to the regulators 20a and 20b, A third discharge port 33c provided in the valve body 31 and connected to the tank T and a second discharge port 33b provided in the valve body 31 between the first position and the second position, And a spool 35 which is movably installed.

The valve body 31 is provided with a pressure receiving portion 34 for pressing one side of the spool 35 and the pressure receiving portion 34 is connected to a pilot line for transmitting the pilot pressure of the gear pump 12. [ (13).

The spool 35 is formed with first to third grooves 35a, 35b and 35c longitudinally spaced from each other, and a pilot passage 36 is formed therein. The pilot passage 36 communicates with the pressure receiving portion 34 as well as with the third groove 35c.

More specifically, the pilot passage 36 includes a first passage 36a formed in the longitudinal direction of the spool 35 and a second passage 36b communicating the end of the first passage 36a with the third groove 35c And a second passage (36b) formed in the radial direction of the spool (35).

The first groove 35a is formed in an annular shape in the spool 35. The first groove 35a connects the first inlet port 32a to the first outlet port 33a, To the port 33c. More specifically, when the spool 35 is in the first position (see Fig. 6A), the first inlet port 32a is connected to the first groove 35a through the first groove 35a, as shown in Figs. 6B and 6C And is connected to the third discharge port 33c. When the spool 35 is in the second position (see FIG. 7A), the first inlet port 32a is connected to the first groove 35a through the first groove 35a, as shown in FIGS. 7B to 7D. And is connected to the discharge port 33a.

The second groove 35b is annularly formed in the spool 35 so as to be spaced apart from the first groove 35a in the longitudinal direction. The second groove 35b connects the second inlet port 32b to the second outlet port 33b or to the third outlet port 33c. More specifically, when the spool 35 is in the first position (see Fig. 6A), the second inlet port 32b is communicated with the second groove 35b through the second groove 35b, as shown in Figs. 6B and 6C And is connected to the third discharge port 33c. At this time, the third discharge port 33c and the second groove 35b are communicated by the connection passage 38 formed in the valve body 31. [ When the spool 35 is in the second position (see FIG. 7A), the second inlet port 32b is connected to the second groove 35b through the second groove 35b, as shown in FIGS. 7B to 7D. And is connected to the discharge port 33b.

The third groove 35c is annularly formed on the spool 35 so as to be positioned between the first groove 35a and the second groove 35b. The third groove 35c is for connecting the pilot passage 36 to the second discharge port 33b. When the spool 35 is in the first position, the pilot oil passage 35, which has passed through the pilot passage 36, As shown in Fig. 6D, to the second discharge port 33b through the third groove 35c.

6D, when the spool 35 is in the first position, the pressure receiving portion 34 is connected to the first discharge port 33a to connect the pilot operating oil to the first discharge port 33a, As shown in FIG.

Hereinafter, the operation of the hydraulic pump control valve having the above-described configuration will be described in detail.

Referring to Fig. 6A, the spool 35 is moved to the first position. This state is a state in which the operating fluid of the gear pump 12 is supplied to the pilot line 13 and the pilot operating fluid is supplied to the pressure receiving portion 34 to move the spool 35 to the right in the drawing.

6B to 6D, each of the first and second inlet ports 32a and 32b is connected to each of the first and second grooves 35a and 35b of the spool 35 And is connected to the third discharge port 33c. That is, a pair of the center bypass lines 14a and 14b are connected to the tank T via one third discharge port 33c. As a result, the operating fluid of the pair of center bypass lines 14a and 14b can be discharged to the tank T through one valve, so that the number of parts to be added can be minimized, .

6D, the pilot hydraulic fluid of the pilot line 13 supplied to the hydraulic pressure portion 34 is supplied to the first discharge port 33a via the hydraulic pressure portion 34, and the hydraulic pressure is supplied to the hydraulic pressure portion 34, The pilot passage 36 and the third groove 35c to the second discharge port 33b. As described above, by forming the pilot passage 36 in one pressure receiving portion 34 and the spool 35 to supply pilot operating oil to the first and second discharge ports 33a and 33b, And the hydraulic pump control valve 30 can be miniaturized.

Referring to FIG. 7A, the spool 35 is moved to the second position. In this state, as shown in Fig. 2, the pilot line 13 is connected to the tank T via the direction switching valve 15. [ Therefore, the pilot pressure is not transmitted to the pressure receiving portion 34, and the spool 35 is moved by the spring 37 to the state as shown in Figs. 7C and 7D.

7B to 7D, each of the first and second inlet ports 32a and 32b is connected to the first and second grooves 35a and 35b of the spool 35 through the respective first and second grooves 35a and 35b, 1 and the second discharge ports 33a, 33b. This allows the operating fluid of each of the pair of the center bypass lines 14a and 14b to be transmitted to each of the regulators 20a and 20b via the first and second discharge ports 33a and 33b.

1 is a hydraulic circuit diagram schematically showing a hydraulic system of a conventional construction machine,

2 is a hydraulic circuit diagram schematically showing a hydraulic circuit of a construction machine to which a hydraulic pump control valve according to an embodiment of the present invention is applied,

3 is a perspective view schematically showing a valve for controlling a hydraulic pump shown in Fig. 2, Fig.

4 is a cross-sectional view taken along line IV-IV in FIG. 3,

5 is a sectional view taken along line V-V in Fig. 3,

FIGS. 6A to 6D are views for explaining the operation of the spool shown in FIG. 4 when the spool is moved to the first position; FIGS.

FIGS. 7A to 7D are views for explaining an operation process in a state where the spool shown in FIG. 4 is moved to the second position.

DESCRIPTION OF THE REFERENCE NUMERALS OF THE DRAWINGS

10a, 10b; First and second hydraulic pumps 12; Gear pump

13; Pilot lines 14a and 14b; Center bypass line

30; A valve 31 for controlling the hydraulic pump; Valve body

32a, 32b; First and second inlet ports 33a, 33b, 33c; The first to third discharge ports

34; Pressure receiving portion 35; spool

35a, 35b, 35c; First to third grooves 36; Pilot path

36a; A first passage 36b; The second passage

Claims (4)

As a hydraulic pump control valve of a construction machine for distributing the pressure of a plurality of the center bypass lines 14a and 14b to the respective regulators 20a and 20b provided in the plurality of hydraulic pumps 10a and 10b A valve body (31); A hydraulic pressure part 34 provided on the valve body 31 and connected to a pilot line 13 to which a pilot hydraulic fluid of the gear pump 12 is supplied; First and second inlet ports 32a and 32b formed in the valve body 31 and connected to the first and second center bypass lines 14a and 14b, respectively; First and second discharge ports 33a and 33b provided on the valve body 31 and connected to the regulators 20a and 20b, respectively; A third discharge port 33c provided on the valve body 31 and connected to the tank T; And The first and second grooves 35a and 35b are provided to be movable between a first position and a second position in the valve body 31 by a pressure applied from the pressure receiving portion 34. The first and second grooves 35a and 35b are spaced apart from each other And a spool (35) When the spool 35 moves to the first position, each of the first and second inlet ports 32a and 32b is connected to the third exhaust port 32a through each of the first and second grooves 35a and 35b, And the first and second inlet ports 32a and 32b are connected to the first and second outlet ports 33a and 33b when the spool 35 moves to the second position. Wherein the hydraulic pump control valve is connected to each of the plurality of hydraulic pumps. The method according to claim 1, When the pilot pressure of the gear pump 12 is applied to the pressure receiving portion 34 and the spool 35 is moved to the first position, the pilot hydraulic fluid supplied to the pressure receiving portion 34 is supplied to the first discharge port 33a) or the second discharge port (33b). The valve for controlling a hydraulic pump of a construction machine according to claim 1, wherein the pilot passage (36) 3. The method of claim 2, The pilot passage (36) A first passage (36a) formed in the spool (35) in the longitudinal direction; And And a second passage (36b) formed to extend to an outer circumferential surface of the spool (35) in a radial direction of the spool (35) so as to communicate with the first passage (36a) . The method of claim 3, , And the second passage (36b) is formed in a third groove (35c) formed between the first and second grooves (35a) and (35b).

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