KR100643010B1 - Hydraulic circuit and confluent valve thereof - Google Patents

Abstract

Operation is prevented from being difficult depending on the type of actuator connected to the service switching valve, and the confluence valve is simplified.

The joining valve 21 connects the downstream side of the third system to the tank at the service end position 32, and the hydraulic pressure of the third pump 13 to the first system and the second system at the service joining position 33. At the same time as to join the pressure oil of the third pump 13 to the service switching valve (20). The operation unit 54 is configured such that, when the first traveling switching valve 16 and the second traveling switching valve 18 and the switching valve of the first system or the second system are operated, the joining valve 21 is located at the service stepping position ( 32, the service joining position 33 is switched to allow the joining to be performed. And even when the operation part 54 is operated and the service switching valve 20 is operated, it switches to the service joining position 33 from the service flow-up position 32. FIG.

Service switching valve, actuator, confluence valve, service cutoff position, tank, service joining position, control panel, pump

Description

HYDRAULIC CIRCUIT AND CONFLUENT VALVE THEREOF

1 is a circuit diagram illustrating a hydraulic circuit according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a part of the hydraulic circuit shown in FIG. 1.

3 is a cross-sectional view of the confluence valve used in the hydraulic circuit shown in FIG. 1, showing a state of an unload position.

FIG. 4 is a cross-sectional view of the joining valve used in the hydraulic circuit shown in FIG. 1, showing a state of the service disconnection position.

FIG. 5 is a cross-sectional view of the joining valve used for the hydraulic circuit shown in FIG. 1, showing a state of the service joining position. FIG.

(Explanation of symbols for the main parts of the drawing)

1. Hydraulic circuit

11. First pump

12. Second pump

13. 3rd pump

14, 15, 19, 22, 23, 24. Switching valve

16. Left running switching valve (first running switching valve)

18. Right running switching valve (second running switching valve)

20. Service switching valve

21. Merging valve

32. Service flow location

33. Location of Service

53. Switching valve for joining

54. Solenoid drive part (operation part)

A hydraulic circuit used in a work vehicle or the like having a first to third system each having a plurality of switching valves connected to a pump, wherein the first traveling switching valve is connected to the first system and the second traveling switching valve is connected to the second system. And a hydraulic circuit having a service switching valve connected to various actuators. Moreover, it is related with the valve used for the hydraulic circuit.

Conventionally, in a hydraulic circuit used in a work vehicle or the like, each of the first to third systems having a first to third systems connected to a pump and having a plurality of switching valves, the first system to the first system, the second system to the second system It is known to have a travel switching valve and a service switching valve connected to various actuators (see Patent Document 1, for example). In the hydraulic circuit described in this patent document 1, there is provided a confluence valve (communication valve) for bringing together the pressurized oil of the third pump to the first system and the second system and joining the pressurized oil of the third pump to the service switching valve. . That is, by switching the confluence valve to the traveling independent position (second switching position), the hydraulic pressure of the third pump is joined to the first system and the second system, and the switching valve other than the traveling switching valves of the first and second systems. The pressure oil of the third pump can be supplied to the pump. Further, by switching the confluence valve to the service confluence position (first switch position), the pressure oil of the third pump can be joined to the service switch valve.

(Patent Document 1-Japanese Patent Application Laid-Open No. 2001-182706 (page 2-4, Figure 1))

Various actuators, such as a large flow rate actuator requiring a large flow pressure oil and a low flow rate actuator sufficient for low flow oil pressure, are connected to the service switching valve as necessary. However, the joining valve in the hydraulic circuit described in Patent Literature 1 has a service joining position for joining the pressure oil of the third pump to the service switching valve in addition to the traveling independent position, but the tank downstream of the third system is provided. And the service switching valve for supplying the pressurized oil of the second pump only is not provided with the service switching valve. For this reason, when the low flow rate actuator is connected to the service switching valve, when the service changeover valve is operated by switching to the service confluence position, the pressure oil of the third pump also joins, so that the operation speed of the low flow rate actuator is increased, making operation difficult. (It becomes difficult to operate). In addition, if the service step flow position is increased in the confluence valve, the confluence valve becomes complicated, and processing becomes difficult.

In view of the above circumstances, the present invention can be suppressed from being difficult to operate according to the type of actuator connected to the service selector valve, and can be used in a hydraulic circuit capable of simplifying the merging valve, and the hydraulic circuit. It is an object to provide a confluence valve.

The hydraulic circuit of the present invention includes a first system connected to a first pump and having a plurality of selector valves, a second system connected to a second pump and having a plurality of selector valves and a plurality of selector valves. It has a third system having a, the first system is provided with a first running switching valve, the second system is provided with a second running switching valve and the service switching valve, the first system and the second system And a joining valve for joining the pressurized oil of the third pump and simultaneously joining the pressurized oil of the third pump to the service switching valve.

And the hydraulic circuit of this invention has several characteristics as follows in order to achieve the said objective. That is, the hydraulic circuit of this invention is equipped with the following features individually or in combination suitably.

A first feature of the hydraulic circuit of the present invention for achieving the above object is that the joining valve includes a service step position for connecting a downstream side of the third system to a tank, and the first system and the second system. And a service joining position for joining the pressurized oil of the third pump to the system and joining the pressurized oil of the third pump to the service switching valve, wherein the first running switching valve and the second running switching valve are provided. When the switching valve of the first system or the second system is operated, the operation valve is switched from the service end position to the service operation position, and an operation unit is installed to allow the operation to be performed, and the operation unit allows the operation. And the service switching valve is switched to the service joining position even when the service switching valve is operated.

According to this configuration, since the service disconnection position for connecting the downstream side of the third system to the tank is provided, it is possible to suppress the difficulty of operation depending on the type of actuator connected to the service switching valve. And when the operation unit and the service switching valve are operated (when service joining), the switch is switched to the service joining position, and when the first and second running switching valves and the switching valve of the first system or the second system are operated (driving independent). In addition, since it is configured to be switched to the service switching valve, the service joining position and the driving independent position can be made into one. Therefore, the confluence valve can be simplified.

A second feature of the hydraulic circuit of the present invention is a pilot chamber provided in the confluence valve, a first pilot passage connecting the pilot chamber and the pilot pump, and branched between the pilot chamber and the pilot pump. A second pilot passage communicating with the service sub-valve connected to the service switching valve, a third pilot passage branched from the first pilot passage and connected to the tank, and a joining switching valve capable of blocking the third pilot passage; The service sub-valve is provided with a communication position that allows the second pilot passage to be connected to the tank when the service selector valve is neutral, and blocks the second pilot passage when the service selector valve is switched. The shut-off position is provided, and the joining switching valve is configured to drive the third pilot passage in cooperation with the operation unit. To.

According to this configuration, when the service switching valve is operated, the second pilot passage is closed, and when the operation unit is operated, the third pilot passage is closed. When the second and third pilot passages are closed, pressure is generated in the pilot chamber, and the joining valve is switched to the service joining position. Accordingly, the configuration in which the operation unit is operated and the service switching valve is switched to the service joining position can be realized with a simple configuration only by adding the joining switching valve.

A third feature of the hydraulic circuit of the present invention is at least one of the first and second traveling switching valves and the switching valves other than the service switching valve in the first system and the second system. And, when the first travel switching valve and the second travel switching valve are operated, a pilot independent pilot passage for generating a pilot pressure for switching the joining valve from the service stepping position to the service joining position is formed. The third pilot passage and the second pilot passage are connected to the pilot independent pilot passage.

According to this configuration, since the second pilot passage and the third pilot passage are connected to the traveling independent pilot passage, a pilot chamber in which the pilot pressure is generated when the second pilot passage and the third pilot passage is closed, and a pilot independent pilot It is possible to share a pilot chamber in which pilot pressure occurs when the passage is closed. Therefore, the confluence valve and the pilot passage can be made simple.

In addition, the confluence valve of the present invention is a confluence valve used for any one of the hydraulic circuits described above, and communicates with the third pump while communicating with a supply passage for supplying pressure oil to the valve main body to the switching valve of the third system. A pump passage, a first joining passage communicating with the first system, a second joining passage communicating with the second system, a tank passage connected to the tank, and an unloading passage connected downstream of the third system And a spool which is slidably inserted into the spool hole, and a pilot chamber installed at one end of the spool, and an unload position for communicating the pump passage with the tank passage, and blocking the pump passage and the tank passage. And a service flow cutoff position for communicating the unload passage and the tank passage, blocking the pump passage and the tank passage, and blocking the unload passage and the tank passage. And wherein a and a service joining position which communicates the load passage and the first passage and the second joining the confluent passage.

According to this configuration, it is possible to switch to three positions of the unload position, the service cutoff position, and the service joining position, and one valve can have three functions.

(The best mode for carrying out the invention)

EMBODIMENT OF THE INVENTION Hereinafter, the best form for implementing this invention is demonstrated, referring drawings. FIG. 1 is a hydraulic circuit diagram showing an oil pressure circuit 1 used in a work vehicle or the like by illustrating the oil pressure circuit according to the embodiment of the present invention. The hydraulic circuit 1 shown in FIG. 1 is connected to the first pump 11 (P1) and has a first system having a plurality of switching valves 14, 15, and 16, and a second pump 12 ( A second system connected to P2 and having a plurality of selector valves 18, 19, and 20 and a plurality of selector valves 22, 23, and 24 connected to a third pump 13 (P3). It has a third system.

The first system includes a left running switching valve (first running switching valve) 16 for controlling the left traveling motor, a boom switching valve 15 for controlling the boom cylinder 26 for operating the boom, and A bucket switching valve 14 for controlling the bucket cylinder 25 for operating the bucket is provided. The left running switching valve 16, the boom switching valve 15, and the bucket switching valve 14 are connected in series to the downstream side of the first pump 11 in this order so that the hydraulic oil is supplied.

The second system includes a right running switching valve (second running switching valve) 18 for controlling the right traveling motor, an arm switching valve 19 for controlling the arm cylinder 27 for operating the arm, , The service switching valve 20 is provided. The service switching valve 20 is connected to various actuators such as a large flow rate actuator requiring a large flow pressure oil and a small flow rate actuator sufficient for the small flow pressure oil. The service actuator is connected via the service ports A4 and B4. In addition, the right-side driving switching valve 18, the female switching valve 19, and the service switching valve 20 are connected in series to the downstream side of the second pump 12 in this order so that the hydraulic oil is supplied. have.

In addition, a switching valve 17 is provided between the first system and the second system. The switching valve 17 has a tank communication position that communicates downstream of the first pump 11 and the second pump 12 to the tanks T1 and T2 (hereinafter simply referred to as "tanks"), and the tank. It is provided with a supply position which cuts off the communication with and connects to the supply passage which supplies pressure oil to the switching valve downstream of each pump. And, by the pilot pressure from the pilot pump, it is possible to switch from the tank communication position to the supply position.

The third system includes a boom swing switching valve 24 for controlling the boom swing cylinder 29 for boom swing operation, and a blade switching valve 23 for controlling the blade cylinder 28 for operating the blade. And a swing switching valve 22 for controlling the swing motor. The boom swing selector valve 24, the blade selector valve 23, and the swing selector valve 22 are provided in this order by a supply passage 30 for supplying pressure oil to each selector valve of the third system. It is connected in series as it is, and a hydraulic oil is supplied.

In addition, the hydraulic circuit 1 joins the pressure oil of the third pump 13 to the first system and the second system, and simultaneously joins the pressure oil of the third pump 13 to the service switching valve 20. ) Is provided. 2 shows an enlarged portion of the confluence valve 21. As shown in Figs. 1 and 2, this confluence valve 21 is switched by pilot pressure and has three positions: an unloading position 31, a service stepping position 32, and a service joining position 33. have.

1 and 2, the joining valve 21 is maintained at the unloaded position 31 in the state where the pilot pressure is not generated. In the unloading position 31, the downstream side of the supply passage 30 is connected to the tank port 36 formed in the confluence valve 21 to communicate with the tank. The pump passage 37, which is formed in the confluence valve 21 and communicates with the supply passage 30 and communicates with the third pump 13, is connected to the tank port 36 to communicate with the tank. Thereby, the unloading position which can return the pressurized oil of the 3rd pump 13 to a tank without passing through the switching valves 24, 23, 22 can be ensured.

The service stepping position 32 is switched by generating a pilot pressure in the pilot chamber 38 provided in the joining valve 21. When switched to the service cut-off position 32, the downstream side of the supply passage 30 (downstream side of the third system) is connected to the tank port 36 and connected to the tank. Accordingly, the pressure oil of the third pump 13 is not supplied to the service switching valve 20 of the second system, and only the pressure oil of the second pump 12 is supplied to the service switching valve 20. (The position of service flow can be secured). Therefore, when the low flow rate actuator is connected to the service switching valve 20 by switching the confluence valve 21 to the service disconnection position 32, the pressure oil of the third pump 13 does not join, and the operating speed of the low flow rate actuator is Can be suppressed to be too fast and difficult to operate.

The service joining position 33 is switched by generating a pilot pressure in the pilot chamber 39 provided in the joining valve 21. When switching to the service joining position 33, the downstream side of the supply passage 30 is connected to the first port 34 and the second port 35 formed on the joining valve 21. As a result, the downstream side of the supply passage 30 is connected to the first passage 40 through the first port 34 and to the second passage 41 via the second port 35. The first passage 40 is connected in parallel with the boom switching valve 15 and the bucket switching valve 14 which are switching valves other than the left travel switching valve 16 in the first system. In addition, the second passage 41 is connected in parallel with the female switching valve 19 and the service switching valve 20 which are switching valves other than the right-side traveling switching valve 18 in the second system. That is, the pressure oil of the third pump 13 is joined to the first system and the second system, and the pressure oil of the third pump 13 is joined to the service switching valve 20. Therefore, the service joining position 33 fulfills the function of the service joining position for supplying the pressure oil of the third pump 13 to the service selector valve 20, and at the same time, the switching valve for driving in the first system and the second system. It can also function as a running independent position for supplying the pressurized oil of the third pump 13 to the switching valves other than (16, 18).

Next, based on FIG. 1, 2, the structure which switches the confluence valve 21 from the unloaded position 31 to another position is demonstrated. First, the service flow-flow position 32 is switched by generating a pilot pressure in the pilot chamber 38 through the pilot passage 42. The pilot passage 42 is connected to the pilot pump 44 via the solenoid drive valve 43. The solenoid drive valve 43 is excited to communicate with the pilot pump 44 to communicate with the pilot chamber. The pilot pressure is generated at 38.

Next, a configuration for switching the confluence valve 21 from the service confluence position 32 to the service confluence position 33 will be described. In the hydraulic circuit 1, a pilot chamber 39, a first pilot passage 45, a second pilot passage 46, a third pilot passage 47, and a pilot independent pilot passage 48 are provided.

The first pilot passage 45 connects the pilot chamber 39 and the pilot pump 44. Moreover, the throttling part is provided between the pilot passage 42, and the pilot pressure which switches to the service flow-flow position 32 is possible to generate | occur | produce in the pilot passage 42. As shown in FIG. The second pilot passage 46 branches from the pilot chamber 39 and the pilot pump 44 to communicate with the service sub valve 49 connected to the service switching valve 20. The third pilot passage 47 branches from the first pilot passage 45 and is connected to the tank via the pilot independent passage passage 48.

The running independent pilot passage 48 is connected to the second pilot passage 46 and the third pilot passage 47 by a service sub-valve 49. The traveling independent pilot passage 48 is provided with a traveling switching valve passage 48a and a work switching valve passage 48b branched from the arm switching valve 19 of the second system.

The passage switching valve passage 48a is connected in parallel to each of the sub valves connected to the right traveling switching valve 18 and the left traveling switching valve 16, respectively. Both downstream connected to both sub valves communicate with a tank. Accordingly, when at least one of the left and right travel switching valves 16 and 18 is in a neutral position, the tank communicates with the tank, and when either of the left and right travel switching valves 16 and 18 is switched, the passage for the travel switching valve is 48a is blocked.

In addition, the work switching valve passage 48b connects each of the sub valves connected to the female switching valve 19, the bucket switching valve 14, and the boom switching valve 15 in this order in series, It communicates with the tank downstream. For this reason, when all the switching valves 19, 14, 15 are in a neutral position, they communicate with the tank, and when at least one of the switching valves 19, 14, 15 is switched, the passage for the work switching valve ( 48b) is blocked.

Therefore, the pilot independent passage passage 48 is the switching valves 19, 14, and 15 except for the two running switching valves 16 and 18 and the service switching valve 20 in the first and second systems. Communication with the tank is interrupted when at least one of the switching valves, the left traveling switching valve 16 and the right traveling switching valve 18 is operated. At this time, since the downstream of both the second pilot passage 46 and the third pilot passage 47 is blocked, the pilot pressure for switching the joining valve 21 from the service disconnection position 32 to the service joining position 33. It is generated in the pilot chamber 39 through the first pilot passage 45. Therefore, when the left and right traveling switching valves and any one of the work switching valves 14, 15 and 19 are operated, the joining valve 21 is switched to the traveling independent position (service joining position).

Moreover, the hydraulic circuit 1 is equipped with the another structure which switches to the service joining position 33. As shown in FIG. In the path of the third pilot passage 47, a joining switching valve 53 capable of blocking the third pilot passage 47 is provided. This joining switching valve 53 is connected to the solenoid drive part 54. By energizing (operating) the solenoid drive unit 54, the joining switching valve 53 is switched from the communicating position 53a to the shutoff position 53b (the joining switching valve 53 is the solenoid driving unit 54). The third pilot passage 47 is interlocked with each other), and the flow of the pilot pressure oil from the third pilot passage 47 to the pilot independent pilot passage 48 is blocked. Accordingly, the solenoid drive unit 54 is provided with the joining valve 21 in the service stepping position when the left and right traveling switching valves 16 and 18 and the first or second system switching valves 14, 15 and 19 are operated. At 32, a switch is made to the service joining position 33, and the operation unit 54 is configured to allow the joining to be performed.

In addition, the service sub-valve 49 of the service selector valve 20 includes a communication position 51 which enables the second pilot passage 46 to be connected to the tank when the service selector valve 20 is neutral, and a service selector valve. It is provided with the blocking positions 50 and 52 which block the 2nd pilot path 46 at the time of switching of 20. As shown in FIG. Accordingly, when the service switching valve 20 is operated, the second pilot passage 46 is closed. On the other hand, when the operation unit 54 is operated, the third pilot passage 47 is also closed. When both the second pilot passage 46 and the third pilot passage 47 are closed, the pilot pressure is applied to the pilot chamber 39 through the first pilot passage 45 as in the case where the independent driving pilot passage 48 is closed. As this occurs, the joining valve 21 is switched to the service joining position 33. Therefore, even when the operation part 54 is operated and the service changeover valve 20 is operated, it is possible to switch from the service stepping position 32 to the service joining position 33.

According to the hydraulic circuit 1 described above, since the service cut-off position 32 is provided, it can be suppressed that the operation becomes difficult depending on the type of actuator connected to the service switching valve 20. When the operation unit 54 and the service switching valve 20 are operated (at the time of service joining), the operation unit 54 is switched to the service joining position 33 and the left and right traveling switching valve and the first or second system switching valve can be operated. By being configured to switch to the service switching valve 20 at the time (when driving independent), the service joining position and the driving independent position can be made into one. Therefore, the confluence valve can be simplified.

Moreover, according to the hydraulic circuit 1, when the operation part 54 is operated and the service switching valve 20 is operated, the structure which switches to the service joining position 33 is added, and only the joining switching valve 21 is added. It can be realized with a simple configuration.

In addition, according to the hydraulic circuit 1, since the second pilot passage 46 and the third pilot passage 47 are connected to the pilot independent passage passage 48, the second pilot passage 46 and the third The pilot chamber 39 in which the pilot pressure is generated when the pilot passage 47 is closed and the pilot chamber 39 in which the pilot pressure is generated when the driving independent pilot passage 48 is closed can be shared. Therefore, the confluence valve and the pilot passage can be made simple.

Next, the valve configuration of the joining valve 21 used in the hydraulic circuit 1 will be described based on the cross-sectional view (Figs. 3 to 5) of the joining valve 21. The confluence valve 21 has a pump passage 37, a first confluence passage 55, a second confluence passage 56, a tank passage 57, an unload passage 58, and a spool hole 59 in the valve body. , The spool 60, the pilot chambers 38, 39, and the like are formed.

In FIG. 3, the pump passage 37 communicates with the third pump 13 through the pump port 61. In addition, the pump passage 37 communicates with an upstream side of the supply passage 30 through a passage 62 opening in the pump passage 37. The first joining passage 55 connects to the first passage 40 via the first port 34 and communicates with the first system while the check valve 64 is installed on the way (see FIGS. 1 and 2). . The second confluence passage 56 is provided with a check valve 63 on the way and is connected to the second passage 41 via the second port 35 to communicate with the second system (Figs. 1 and 2). Reference). The tank passage 57 communicates with the tank via the tank port 65. The unload passage 58 is connected downstream of the third system (downstream of the supply passage 30). The spool 60 is inserted freely in the spool hole 59. In addition, the pump passage 37, the first confluence passage 55, the second confluence passage 56, the tank passage 57, and the unload passage 58 are opened in the spool hole 59. In addition, a communication path 70 that can communicate with the pump passage 37, the tank passage 57, and the unload passage 58 is also provided. In addition, the pilot chambers 38 and 39 are provided at one end of the spool 60. The pilot pressure is generated in the pilot chamber 38 through the pilot passage 42, and the pilot pressure is generated in the pilot chamber 39 through the first pilot passage 45 (see FIGS. 1 and 2).

3 shows a state when the confluence valve 21 is in the unloaded position 31. In the unloading position 31, the pilot pressure is not generated in the pilot chambers 38 and 39. For this reason, the spool 60 is urged to one end by the spring 66 provided in the other end side of the spool 60. For this reason, the pump passage 37 and the tank passage 57 communicate with each other via the communication passage 70. Accordingly, the pressure oil from the third pump 13 connected to the pump port 61 is connected to the pump passage 37, the communication passage 70, and the tank passage 57, as indicated by arrows in the figure. Through the tank.

4 shows the state when the confluence valve 21 is in the service end position 32. The pilot pressure is generated in the pilot chamber 38 through the pilot passage 42 at the service flow-flow position 32. For this reason, the small spool 67 is pressed toward the spool 60 in the small spool support 68, and the spool 60 which contacts the small spool 67 at one end resists the spring force of the spring 66, It is pressed to the other end side (the spring 66 side). As a result, the pump passage 37 and the tank passage 57 are blocked (the pump passage 37 and the communication passage 70 are blocked), and the unload passage 58 and the tank passage 57 communicate with each other. That is, the pressure oil from the third pump 13 flows out of the tank from the downstream side (downstream side of the third system) of the supply passage 30, not from the pump passage 37, as indicated by the arrow in the figure. .

5 shows a state when the confluence valve 21 is in the service confluence position 33. At the service joining position 33, a pilot pressure is generated in the pilot chamber 39 through the first pilot passage 45 (in addition, the pilot pressure oil flows from the opening 69 into the pilot chamber 39), The spool 60 is pressed against the other end against the spring force. Thus, the pump passage 37 and the tank passage 57 are blocked (the pump passage 37 and the communication passage 70 are blocked), and the unload passage 58 and the tank passage 57 are blocked. Then, the check valve 64 disposed in the first confluence passage 55 and the check valve 63 disposed in the second confluence passage 56 are pushed up to unload passage 58 and the first confluence passage 55, respectively. ) And the second confluence passage 56 communicate with each other (as indicated by arrows in the drawing, the pressure oil of the third pump 13 is supplied to the first and second systems).

According to the merging valve 21 described above, it is possible to switch to the three positions of the unloading position 31, the service stepping position 32, and the service joining position 33 by moving the spool 60. In other words, one valve can have three functions.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change is possible in the range as described in a claim.

According to the structure of Claim 1, since the service stage which connects the downstream side of a 3rd system to a tank is provided, it becomes possible to suppress that operation becomes difficult according to the kind of actuator connected to a service switching valve. And when the operation unit and the service switching valve are operated (when service joining), the switch is switched to the service joining position, and when the first and second running switching valves and the switching valve of the first system or the second system are operated (driving independent). In addition, since it is configured to be switched to the service switching valve, the service joining position and the driving independent position can be made into one. Therefore, the confluence valve can be simplified.

According to the structure of Claim 2, when a service switching valve is operated, a 2nd pilot channel | path is closed, and when a control part is operated, a 3rd pilot channel | path is closed. When the second and third pilot passages are closed, pressure is generated in the pilot chamber, and the joining valve is switched to the service joining position. Accordingly, the configuration in which the operation unit is operated and the service switching valve is switched to the service joining position can be realized with a simple configuration only by adding the joining switching valve.                     

According to the structure of Claim 3, since the 2nd pilot passage and the 3rd pilot passage are connected to the driving independent pilot passage, the pilot chamber which generate | occur | produces a pilot pressure when a 2nd pilot passage and a 3rd pilot passage is closed, and traveling It is possible to share a pilot chamber where pilot pressure occurs when the independent pilot passage is closed. Therefore, the confluence valve and the pilot passage can be made simple.

According to the structure of Claim 4, it can switch to three positions of an unloading position, a service interruption position, and a service confluence position, and can have three functions by one valve.

Claims (4)

A first system connected to the first pump and having a plurality of switching valves, a second system connected to the second pump and having a plurality of switching valves, and a third system connected to the third pump and having a plurality of switching valves; The first system includes a first travel switching valve, the second system includes a second travel switching valve and a service switching valve, and the oil pressure of the third pump is supplied to the first system and the second system. In the hydraulic circuit comprising a confluence valve for joining the pressure switch of the third pump to the service switching valve at the same time, The confluence valve has a service flow-flow position for connecting a downstream side of the third system to a tank, and joins the pressure oil of the third pump to the first system and the second system, and simultaneously connects the pressure switch of the third pump to the service switching valve. A service joining position for joining the pressure oil of the pump; When the first travel switching valve and the second travel switching valve and the switching valve of the first system or the second system are operated, the confluence valve is switched from the service disconnection position to the service confluence position and merges. An operation unit is installed to allow the operation to be performed, And the operation portion is operated to a position to allow the confluence, and is switched from the service flow position to the service confluence position even when the service changeover valve is operated. The method of claim 1, A pilot chamber installed in the confluence valve, A first pilot passage connecting the pilot chamber and the pilot pump; A second pilot passage branching between the pilot chamber and the pilot pump and communicating with a service subvalve connected to the service switching valve; A third pilot passage branching from the first pilot passage and connected to the tank; A joining switching valve capable of blocking the third pilot passage is installed, The service sub-valve may include a communication position that allows the second pilot passage to be connected to a tank when the service selector valve is neutral, and a shutoff position that blocks the second pilot passage when the service selector valve is switched. Equipped, And said joining switching valve shuts off said third pilot passage in conjunction with said operation unit. The method of claim 2, At least one switching valve of the first and second traveling switching valves and the switching valve other than the service switching valve in the first and second systems, the first traveling switching valve and the second traveling switching When the valve is operated, a pilot independent pilot passage for generating a pilot pressure for switching the merging valve from the service end position to the service merging position is formed. And the third pilot passage and the second pilot passage are connected to the traveling independent pilot passage. A merging valve used for the hydraulic circuit according to any one of claims 1 to 3, A pump passage communicating with the valve body to a supply passage for supplying pressure oil to the switching valve of the third system and communicating with the third pump, a first joining passage communicating with the first system, and the second system A second joining passage communicating with the tank, a tank passage connected to the tank, an unload passage connected to a downstream side of the third system, a spool slidably inserted into the spool hole, and a pilot chamber provided at one end of the spool. Formed, An unload position communicating the pump passage with the tank passage; A service cut-off position for blocking the pump passage and the tank passage and communicating the unload passage and the tank passage; And a service joining position for blocking the pump passage and the tank passage, blocking the unload passage and the tank passage, and communicating with the unload passage, the first confluence passage and the second confluence passage. Confluence valve.

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