KR20020050339A - Hydraulic circuit for excavator with an option device - Google Patents

Abstract

PURPOSE: Provided is a hydraulic control circuit by selectively using any one of existing dual control valves to control an optional device as a spool without alternative spool and to eliminate unbalance of hydraulic pressure distribution. CONSTITUTION: The control circuit comprises a first and a second main hydraulic pumps(10,20) activated by a common engine(E) and auxiliary pump(40); a control valve block(30-1,30-2) including a number of control valves(31,32,33,34,35,36) to selectively provide controlled compressed oil stream injected from the first and the second pumps(10,20) into an optional device(9) and/or other several actuators(3); and a number of joystick valves(50) to generate pilot signal pressure to control the control valves by decreasing pressure of the compressed oil from the auxiliary pump(40). The control valves(31 to 36) include a single control valve(32) and a dual control valve(35).

Description

HYDRAULIC CIRCUIT FOR EXCAVATOR WITH AN OPTION DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pressure control circuit of an excavator, and more particularly, to an oil pressure control circuit of an optional work device such as a breaker or the like attached to the front end of the front.

Excavator is used to replace the bucket mainly used for excavation work with various kinds of additional work devices, called 'option device' such as breaker, crusher, organ, etc. according to the work type. Excavator which can install the optional device in this way is composed of a hydraulic circuit as shown in FIG.

That is, the option device hydraulic control circuit of the conventional excavator, as shown in Figure 4, the first main pump 101 and the second main pump 102, the first main pump 101 is a first A plurality of control valves, for example, right driving control valve 104, optional device control valve 105 such as a breaker, bucket control valve 106, boom 1 speed control valve 107, arm through the oil pressure line 103 It is connected in parallel to the second speed control valve 108 to operate each actuator, and the second main pump 102 is connected to a plurality of other control valves, for example, a left driving control via the second pressure oil line 110. The valve 111, the swing control valve 112, the boom 2 speed control valve 113, and the arm 1 speed control valve 114 are connected in parallel.

However, in the conventional excavator hydraulic circuit shown in FIG. 4, the service spool for the option device is separately installed in the control valve block to use the option device, resulting in a complicated control valve block and an increase in unit cost. In addition, when the option device and the other actuators are combined, the balance of distribution of the pressure oil supplied from the main hydraulic pump may be broken, resulting in irregular operation of the option device or the other actuators, or the operation may not be performed smoothly.

Therefore, the present invention is designed to improve the disadvantages of the hydraulic control method of the excavator equipped with the option device of the conventional excavator, a service spool for controlling the option device is not separately installed in the control valve block, other control valve spool By simplifying the control valve structure, and by combining the optional device and other actuators at the same time, the oil pressure of the hydraulic pump can be efficiently distributed according to the working characteristics to provide the hydraulic control circuit for the optional device. Has its purpose.

1 is a first embodiment of an option device hydraulic control circuit of an excavator according to the present invention,

Figure 2 is a second embodiment of the hydraulic control circuit of the option device of the excavator according to the present invention,

Figure 3 is a third embodiment of the hydraulic control circuit of the option device of the excavator according to the present invention,

Figure 4 is a conventional excavator hydraulic circuit diagram.

※ Explanation of code about main part of drawing ※

10: first main hydraulic pump 11: the first hydraulic line

20: the second main hydraulic pump 21: the second hydraulic line

30-1: 1st control valve block 30-2: 2nd control valve block

31, 33, 34, 36: Control valve 32: 1-speed control valve

35: 2-speed control valve 35a: 2-speed spool

35b: Option operating spool 35c, 35d: Hydraulic section

37: oil pressure line 38: 2 speed lines

39: check valve 40: auxiliary pump

41: Option device selection valve 42: Option line

43: Option device selector switch 44: Option device operating valve

45a, 45b: Option unit control line 46: Option unit control valve

47: Shuttle valve 48: 2-speed signal shutoff valve

49: Option signal line 50: Joystick valve

51: joystick valve 52: 1 speed pilot line

53: 2nd Speed Pilotline

The present invention for achieving the above object is a plurality of actuators including an auxiliary pump operated by the engine, at least two main hydraulic pumps, an optional device operated by the pressure oil of the main hydraulic pump, and each of the main First and second control valve block consisting of a plurality of control valves for receiving the pressure oil from the hydraulic pump to control the flow of the pressure oil to the plurality of actuators, and a plurality of control valves by reducing the pressure oil of the auxiliary pump In the hydraulic device control circuit of an optional device of an excavator having two joystick valves, the first and second control valve blocks are supplied with pressure oil from the main hydraulic pump to control the flow of hydraulic oil to any one of the same actuators. A valve and a two-speed control valve, respectively, wherein the two-speed control valve is any one of the actuator Furnace is provided with a two-speed spool to control the flow of the pressurized oil, the second-speed control valve is equipped with an optional device operating spool to block the second-speed function when using the optional device and to control the flow of the pressure oil to be supplied only to the optional device, To this end, an option device selection means is connected to the option unit operating spool side hydraulic unit of the second speed control valve.

The optional device selection means is configured to be selectively connected to the auxiliary pump or the drain tank through an option signal line connected to the hydraulic pressure line of the option device operating spool side, and the second pressure spool side hydraulic pressure of the second speed control valve. The part is connected to the joystick valve through the second speed pilot line.

In the present invention, the option device selection means is an option device selection valve having an option device selection switch and an internal flow path installed on the option signal line to selectively connect the hydraulic pressure portion of the operation spool to the auxiliary pump or the drain tank. The option device selection valve may be configured to be connected to the option device selection switch.

The present invention further includes an option device control means for controlling the option device by receiving pressure oil through the option signal line when the option device selection means is selected. The option device control means is configured with an option device operation valve for controlling the control valve of the option device by receiving pressure oil from the option signal line.

And the present invention further comprises a second speed signal blocking means for connecting the water pressure portion of the second speed spool to the drain tank and at the same time blocking the second speed pilot line when selecting the option device selection means on the second speed pilot line; It may be.

The hydraulic control circuit of the present invention having the above-described configuration enables the selective use of the second speed control valve and the optional device control function by selecting one of the two speed control valves without installing the optional device control valve in the control valve block separately. No need to install a separate control valve for optional equipment, so the structure of the control valve block can be simplified, reducing the cost. When working with optional equipment, there is not a separate service spool for the optional equipment, but by simply converting the second speed spool to the optional equipment, it is possible to improve the workability by efficiently distributing the hydraulic pressure of the main hydraulic pump. It becomes possible.

Hereinafter, an embodiment of an optional device hydraulic control circuit of an excavator according to the present invention will be described in detail according to the accompanying drawings.

1 to 3 show each embodiment of the hydraulic control circuit of the excavator according to the present invention. Each of these embodiments has the first and second main hydraulic pumps 10 and 20 and the auxiliary pump 40 which are operated by the engine E in common, and the first and second main hydraulic pumps 10 and 20 respectively. By controlling the flow of the discharged oil to be selectively supplied to the option device 9 or the plurality of actuators 3, the plurality of control valves 31 for operatively controlling the plurality of actuators 3 in addition to these option devices 9, The control valve blocks 30-1, 30-2 including 32, 33, 34, 35, and 36 and the pressure oil of the auxiliary pump 40 are reduced in pressure to control the plurality of control valves 31, 32, 33, 34. And a plurality of joystick valves 50 for generating a pilot signal pressure for controlling 35 and 36.

By the way, the actuator of reference numeral 3, when the option device 9 is not used due to the working characteristics, respectively receives the pressure oil from the first main hydraulic pump 10 and the second main hydraulic pump 20 through the first and second speed control valves. An actuator which can be supplied will be described. Hereinafter, it is assumed that the boom cylinder is for convenience of description. Accordingly, reference numerals 32 and 35 also illustrate the first speed control valve 32 and the second speed control valve 35 that control the boom cylinder 3 at one speed or two speeds, respectively.

More specifically, the boom cylinder (3), the boom cylinder (3) lifts and lowers the boom while maintaining high load conditions such as the weight of the boom, arm, bucket corresponding to the excavator's work equipment, and the earth and sand loaded on the bucket. It is an actuator that performs the function to make the speed of the boom up. In particular, the speed of the boom is necessary for speedy operation, especially at high loads. This cylinder has the characteristics of operating only at 1 speed. That is, when the boom is raised, it operates in the second speed state in which pressure oil is simultaneously supplied from the first and second main hydraulic pumps 10 and 20 by the first and second speed control valves 32 and 35, but the first speed is lowered when the boom is raised. The second speed control valve is in an idle state because it operates in a state where only the pressure oil of the first main hydraulic pump 10 is supplied by the control valve.

Here, the first speed control valve 32 is provided with both hydraulic pressure units, each hydraulic unit is connected to the joystick valve 50 through the control line 52-1 or the first speed pilot line 52, respectively, The joystick valve 50 generates a pilot signal pressure in which the pressure oil of the auxiliary pump 40 is reduced by operation to pressurize both hydraulic parts through the control line 52-1 or the first speed pilot line 52. By doing so, the pressure oil of the first main hydraulic pump 10 is supplied to the boom cylinder 3.

In addition, the second speed control valve 35 is a second speed spool 35a for supplying the pressure oil of the second main hydraulic pump 20 to the boom cylinder 3 through the second speed line 38, and the second main And an option device operating spool 35b for supplying the hydraulic oil of the hydraulic pump 20 to the option device 9 through the option line 42, and the second speed line 38 includes the first speed control valve ( 32) is connected to the oil pressure line 37 for connecting the boom cylinder (3), the check valve 39 is installed on the second speed line (38), the pressure oil discharged from the boom cylinder (3) Prevent backflow to the control valve (35).

A hydraulic pressure unit 35c is provided at an end of the option device operation spool 35b side of the second speed control valve 35, and the hydraulic unit 35c connects the option signal line 49 through an option device selection unit. It is selectively connected to the auxiliary pump 40 or the drain tank (T) through.

At the end of the second speed spool 35a side of the second speed control valve 35, a hydraulic pressure part 35d is provided, and the hydraulic pressure part 35d is connected to the joystick valve 50 through the second speed pilot line 53. Connected.

Example 1:

In the first embodiment of the present invention, as shown in Fig. 1, the option device selection means is installed on the option signal line 49, so that the hydraulic pressure part 35c on the side of the option device operation spool 35b is connected to the auxiliary pump. (40) or a solenoid option device selection valve 41 having an internal flow path selectively connected to the drain tank T, and an option device for supplying or disconnecting power to the solenoid portion of the option device selection valve 41. It is composed of a switch 43.

Embodiment 1 of the present invention configured as described above operates as follows.

When the option device selector switch 43 is turned on, the option device selector valve 41 is switched so that the pressure oil of the auxiliary pump 40 passes through the option signal line 49 to the option device of the second speed control valve 35. It acts on the hydraulic part 35c by the side of the operation spool 35b, and switches the 2 speed control valve 35. As shown in FIG. As a result, the pressure oil of the second main hydraulic pump 20 is supplied toward the option device 9 along the flow path of the option device operation spool 35b of the second speed control valve 35 to operate the option device 9.

At this time, if the driver raises the boom by operating the Joytec valve 50, the boom upward pressure receiving portion 35d of the second speed control valve 35 is a pilot signal decompressed through the second speed pilot line 53. Although the pressure is applied, the option device operating spool 35c is switched by the pressure difference or the pressure difference between the pressure receiving area 35c and the pressure receiving unit 35c which is supplied with the pressure oil of the auxiliary pump 40 from the option signal line 49. Will remain the same. However, the first speed control valve 32 receives the pilot signal pressure reduced through the first speed pilot line 52 and operates the boom cylinder to the first speed state.

On the contrary, when the driver operates the joystick valve 50 to lower the boom, the boom cylinder 3 is connected to the first main hydraulic pump 32 through the first speed control valve 32 switched through the control line 52-1. 10) is supplied with pressure oil, and in addition, it descends at high speed by its own weight.

On the other hand, when the driver turns off the option device selector switch 43, the hydraulic pressure unit 35c on the side of the option device operation spool 35b of the second speed control valve 35 is changed according to the switching of the option device selector valve 41. The option signal line 49 connected to the pump 40 is cut off and connected to the drain tank T to drain the pressurized oil remaining in the water pressure unit 35c. In this case, the second speed control valve 35 is in an original state without using the option device 9, and the first and second speeds are controlled through the pilot lines 52 and 53 during the boom raising operation by the joystick valve 50. By simultaneously switching the control valves 32 and 35, the ascending speed of the boom is operated at the second speed state, and during operation of the boom lowering operation, one hydraulic part of the first speed control valve 32 is controlled through the control line 52-1. By operating the first speed pilot signal, only the pressure oil of the first main hydraulic pump 10 is supplied to the boom cylinder 3, but as described above, the boom cylinder 3 is in a high load state and thus descends at a high speed. . At this time, the pressurized oil drained from the boom cylinder 3 is drained by the check valve 39 not through the second speed control valve 35 but only through the first speed control valve 32. 35 is to be commercially available only for the option device 9.

Example 2:

As shown in FIG. 2, the second embodiment of the present invention is the second speed spool 35a side from the joystick valve 50 when the option signal acts on the option signal line 49 as the option device selection means is selected. The second speed control valve 35 is connected to the drain tank T while the second speed pilot line 53 connected to the water pressure part 35d is blocked, and the second speed control valve 35 is connected to the optional device operation spool 35b. Characterized in that it further comprises a two-speed signal blocking means to be maintained only in position.

In this case, the second speed signal blocking means is installed on the second speed pilot line 53 to switch the spool by receiving the pressure oil from the option signal line 49 only when the oil pressure acts on the option signal line 49. Therefore, the second speed pilot line 53 is blocked and at the same time, the second speed control valve 35 is composed of a two speed signal shutoff valve 48 which communicates with the drain tank T the pressure receiving part 35d. .

On the other hand, the two-speed signal shut-off valve 48 can be replaced by the solenoid valve of the electric drive method, not the hydraulic drive method as described above, the electric drive solenoid valve is connected to the option device selection switch 43 In this configuration, the same operation and effect as those of the hydraulic-type two-speed signal shutoff valve 48 can be obtained.

Embodiment 2 of the present invention configured as described above operates as follows.

When the option device operation switch 43 is turned on to operate the option device 9, the option device selection valve 41 receiving the electrical signal from the option device operation switch 43 is connected to the auxiliary pump 40 and the option signal line 49. In addition, the option signal pressure acts on the hydraulic pressure part 35c of the option operating device spool 35b of the second speed control valve 35, and also acts on the hydraulic pressure part of the second speed signal shutoff valve 48. When the 2-speed signal shut-off valve 48 is switched according to the option signal pressure, the pressure oil remaining in the pressure-receiving portion 35d on the 2-speed spool 35a side of the 2-speed control valve 35 is a 2-speed signal cut-off valve ( 48, the second-speed pilot line 53, which is drained to the drain tank T and connects the joystick valve 50 and the hydraulic part 35d on the second-speed spool 35a side, is blocked and the second-speed control The valve 35 can be smoothly switched to the option device operating spool 35b regardless of the operation direction of the joystick valve 50.

Accordingly, the pressure oil of the second main hydraulic pump 20 is supplied only toward the option device 9 through the option device operating spool 35b of the second speed control valve 35 regardless of the operation of the joystick valve 50. The hydraulic pressure of the first main hydraulic pump 10 is supplied to the boom cylinder 3 through the first speed control valve 32 according to the driver's joystick valve 50 operating direction.

Therefore, while operating the option device 9, the boom cylinder 3 is operated only at 1 speed, but the complexity of the hydraulic circuit and the imbalance of the hydraulic oil of the main hydraulic pump by adopting a separate service spool as in the prior art Will be able to solve.

Considering that the combined operation of simultaneously performing the option device 9 and the boom raising operation is an infrequently used type of work, the speed of the boom is slightly lowered to 1 speed during the combined operation of the boom and the option device. This is not a big problem compared to the effect.

On the other hand, if the option device selection switch 43 is not turned on, the option device operation valve 41 does not operate as described in Embodiment 1, so that the option signal pressure does not act on the option signal line 49, and accordingly, Since the two-speed signal blocking valve 48 also does not operate, the boom cylinder is operated in the second speed state according to the operation direction of the joystick valve 50.

Example 3:

Embodiment 3 of the present invention, as shown in Figure 3, in addition to the configuration of the second embodiment of the present invention option line 42 for supplying pressure oil from the second speed control valve 35 to the option device (9) An option device control valve 46 for controlling the flow of the pressurized oil is installed on the option, while an option device operating valve 44 extends and is installed on the option signal line 49. The optional device control valve is provided through a pair of control lines 45a and 45b to selectively supply the hydraulic oil supplied from the option signal line 49 to both hydraulic parts of the option device control valve 46 according to the operation direction. Connect with (46).

In addition, on the pair of control lines 45a and 45b, a shuttle valve 47 is installed at both ends connected to the control lines 45a and 45b, but the shuttle valve 47 is a pair of control lines 45a. 45b) is applied so that the oil pressure of the control line with the higher pressure is applied to the hydraulic pressure portion of the 2-speed signal cut-off valve 48 to switch the 2-speed signal cut-off valve 48.

Embodiment 3 of the present invention configured as described above operates as follows.

When the option device operation switch 43 is turned on to operate the option device 9, the option device selection valve 41 communicates the option signal line 49 and the auxiliary tank 40 with each other to the option signal line 49. By sending the option signal pressure oil to pressurize the hydraulic pressure part 35c on the side of the option device operating spool 35b of the second speed control valve 35 as in the first and second embodiments, the option device also operates toward the option device operating valve 44. Supply signal pressure oil. When the driver operates the option device operating valve 44 in this state, the option signal pressure oil passes through the operating valve 44 through one of the pair of control lines 45a and 45b to control the option device control valve. The hydraulic pressure of the second main hydraulic pump 20 supplied through the option line 42 is switched to the option device control valve 46 as a result of acting on one side hydraulic part of the 46. It works. At this time, the second speed shut-off valve 48 is switched by receiving the pressure oil flowing in the control lines (45a, 45b) through the shuttle valve 47, thereby, as in the second embodiment of the present invention, the second speed control valve (35) is an option irrespective of whether or not the joystick valve 50 is operated because the hydraulic part 35d is connected to the second speed pilot line 53 connected to the joystick valve 50 and is connected to the drain tank T at the same time. It will be kept switched to the position of the device operation spool 35b. Therefore, while operating the option device 9, the boom cylinder 3 is to be controlled only at one speed, as in the first and second embodiments.

On the other hand, if the option device operation switch 43 is not turned on, the boom is operated in the second speed state according to the operation of the second speed control valve 35 as in the above-described embodiments 1,2.

As described above, the hydraulic circuit of the excavator according to the present invention can selectively use one of the existing two-speed control valve installed as a spool for the option device to control the option device in the control valve block, the service for a separate option device This eliminates the need to install spools, simplifying the structure of the control valves and hydraulic circuits, as well as eliminating the problem of uneven distribution of the main hydraulic pump by a separate service spool when combined with the optional device and other actuators. It is possible to obtain the effect that the distribution is efficient and the compound operability is improved.

Claims (7)

The auxiliary pump 40 and the first and second main hydraulic pumps 10 and 20 operated by the engine E, A plurality of actuators including an option device 9 operated by receiving pressure oil from the first and second main hydraulic pumps 10 and 20, A first control valve block 30-1 consisting of a plurality of control valves for controlling the flow of the pressurized oil supplied from the first main hydraulic pump 10 to the plurality of actuators; A second control valve block 30-2 composed of a plurality of control valves for controlling the flow of the pressurized oil supplied from the second main hydraulic pump 20 to the plurality of actuators; A first speed control valve 32 included in the first control valve block 30-1 and controlling a flow of pressure oil supplied from the first main hydraulic pump 10 to a predetermined actuator 3; The flow of pressure oil included in the second control valve block 30-2 and equally supplied from the second main hydraulic pump 20 to the actuator 3 receiving the pressure oil from the first speed control valve 32. 2 speed control valve (35) for controlling the In the hydraulic circuit of the excavator having a plurality of joystick valves 50 for providing a signal pressure for controlling the control valves by reducing the pressure oil of the auxiliary pump 40, The second speed control valve 35 is a second speed spool 35a for controlling the flow of pressure oil supplied to the actuator 3 and an option device operation spool for controlling the flow of pressure oil supplied to the option device 9. (35b) and pressure receiving parts (35c, d) at both ends, The hydraulic pressure unit 35c on the side of the option device operation spool 35b receives the flow of pressure oil supplied from the second main hydraulic pump 20 to the actuator 3 via the second speed control valve 35. Option device hydraulic control circuit of the excavator, characterized in that connected to the option device selection means for switching the second speed control valve (35) to be supplied preferentially. 2. The pressure receiving part of the option device operating spool 35b according to claim 1, wherein the option device selecting means is installed on an option signal line 49 connected to the pressure receiving part 35c on the side of the option device operating spool 35b. An optional device selection valve 41 having an internal flow path selectively connecting 35c with the auxiliary pump 40 or the drain tank T; Option device hydraulic control circuit of the excavator, characterized in that consisting of the option device selection switch 43 for switching the option device selection valve (41). 3. The option device hydraulic control circuit according to claim 2, wherein the option signal line (49) further comprises an option device control means for controlling the option device (9). 4. The device according to claim 3, characterized in that the option device control means comprises an option device operation valve (44) for receiving pressure oil from the option signal line (49) to control the control valve (46) of the option device (9). Hydraulic control circuit for the excavator's optional equipment. According to claim 1, wherein the second speed spool (35a) side pressure portion (35d) is connected to the joystick valve 50 through the second speed pilot line 53, the middle of the second speed pilot line (53) It further comprises a second speed signal blocking means for disconnecting the second speed pilot line 53 when the option device selection means is selected, and at the same time connecting the hydraulic part 35d of the second speed spool 35a with the drain tank T. Hydraulic control circuit for the optional device of the excavator. 6. The second speed signal blocking means is provided from a shuttle valve 47 connected at both ends to a pair of control lines 45a and 45b between the option device operating valve 44 and the option device control valve 46. Hydraulic control circuit for the optional device of the excavator, characterized in that the two-speed signal blocking valve 48 is operated by receiving a hydraulic signal. 6. The hydraulic control circuit of an option device according to claim 5, wherein the second speed signal blocking means is a second speed signal blocking valve (48) operated by receiving a signal from the option device selection switch (43).