JP2021177100A - Hydraulic system of working machine - Google Patents

Abstract

To provide a hydraulic system of a working machine having excellent operability and versatility.SOLUTION: A hydraulic system of a working machine includes: a hydraulic pump P1; a first hydraulic device 56B; an operation member 58 operated by an operator; an input device 93 being a member different from the operation member, and operated by the operator; an operation valve 59; a solenoid valve 65; and a changing portion capable of changing a first state for supplying a hydraulic fluid to the first hydraulic device from one of the operation valve and the solenoid valve to operate the first hydraulic device, when the operator operates one of the operation member and the input device to operate any one of the operation valve and the solenoid valve, and a second state for supplying the hydraulic fluid of higher pressure selected from the hydraulic fluids supplied by the operation member and the input device, to the first hydraulic device to operate the first hydraulic device, when the operator operates both of the operation member and the input device to operate both of the operation valve and the solenoid valve.SELECTED DRAWING: Figure 5

Description

The present invention relates to, for example, a hydraulic system for working machines such as skid steer loaders and compact truck loaders.

Conventionally, the working machine is operated by an operating system of either a hydraulic system or an electric system. For example, the working machine disclosed in Patent Document 1 can be operated by an operating member, an operating valve in which the pressure of the hydraulic oil output according to the operation of the operating member can be changed, and the hydraulic oil output from the operating valve. It is equipped with hydraulic equipment.
Further, the working machine disclosed in Patent Document 2 includes a control device that outputs a control signal based on the operation amount of the swingable first switch, and a solenoid valve that controls the pilot pressure based on the control signal. A control valve that supplies hydraulic oil to the actuator based on the pilot pressure is provided.

JP-A-2017-67100 JP-A-2015-94443

In the working machine of Patent Document 1, the hydraulic equipment is operated by changing the pressure of the hydraulic oil according to the operation of the operating member. On the other hand, in the working machine of Patent Document 2, the control device controls the solenoid valve and operates the actuator in response to the operation of the switch. However, like the hydraulic system of the work machine disclosed in Patent Document 1 and Patent Document 2, the hydraulic device (actuator) is controlled only by either the hydraulic system or the electric system. Therefore, it has not been possible to obtain the advantages of both a hydraulic system having excellent durability and operability and an electric system capable of fine operation and having excellent versatility.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a hydraulic system for a work machine having excellent operability and versatility.

The technical means of the present invention for solving this technical problem is as follows.
The hydraulic system of the work machine is a hydraulic pump that discharges hydraulic oil, a first hydraulic device that can be operated by the hydraulic oil, an operating member operated by an operator, and a member different from the operating member, and is operated by the operator. An operation valve that has an input device to operate, a rod that moves according to the operation of the operation member, and the pressure of the hydraulic oil can be changed according to the movement of the rod, and an operation valve that moves according to the operation of the input device. When an electromagnetic valve capable of changing the pressure of hydraulic oil and the operator operate one of the operating member and the input device to operate either the operating valve or the electromagnetic valve, the operation valve and the electromagnetic valve are operated from the one. In the first state of supplying hydraulic oil to the first hydraulic device and operating the first hydraulic device, the operator operates both the operating member and the input device to obtain the operating valve and the electromagnetic valve. When both are operated, the second state in which the hydraulic oil having the higher pressure among the hydraulic oils supplied by the operating member and the input device is supplied to the first hydraulic device and the first hydraulic device is operated. It has a change part that can be changed to.

Further, the hydraulic system of the work machine includes a supply oil passage connecting the operation valve and the first hydraulic equipment, and a branch oil passage connected to the solenoid valve and merging with the supply oil passage. ..
Further, the change portion is provided at the confluence of the supply oil passage and the branch oil passage, and communicates the operation valve with the first hydraulic device, so that the solenoid valve and the first hydraulic device are connected to each other. A shuttle valve that can be switched between the first position that regulates the hydraulic oil and the second position that regulates the hydraulic oil between the operating valve and the first hydraulic equipment and communicates the solenoid valve and the first hydraulic equipment. It has.

Further, the hydraulic system of the work machine is provided in the supply oil passage and allows the flow of hydraulic oil from the operation valve to the first hydraulic device, and the operation from the first hydraulic device and the solenoid valve. The first check valve that regulates the flow of hydraulic oil toward the valve, and the first hydraulic pressure that is provided in the branch oil passage and allows the flow of hydraulic oil from the solenoid valve toward the first hydraulic equipment. It is provided with an apparatus and a second check valve that regulates the flow of hydraulic oil from the operating valve to the solenoid valve.

Further, the hydraulic system of the work machine is arranged between the confluence portion of the supply oil passage and the branch oil passage and the first hydraulic equipment, and the first hydraulic pressure from the confluence portion of the supply oil passage. A bypass check valve that allows the flow of hydraulic oil to the equipment and blocks the flow of hydraulic oil from the first flood control equipment to the confluence of the supply oil passage, and a bypass check valve in the supply oil passage. It is provided with a bypass oil passage connected to the entry side and the exit side and provided with a throttle.

According to the present invention, it is possible to provide a hydraulic system for a working machine having excellent operability and versatility.

It is the schematic of the hydraulic system of the traveling system in 1st Embodiment. It is the schematic of the hydraulic system of the work system in 1st Embodiment. It is the schematic of the 1st modification of the work system hydraulic system in 1st Embodiment. It is the schematic of the 2nd modification of the work system hydraulic system in 1st Embodiment. It is the schematic of the hydraulic system of the work system in 2nd Embodiment. It is a side view which shows the truck loader which is an example of a working machine. It is a side view which shows a part of the truck loader in a state where the cabin is raised.

Hereinafter, a preferred embodiment of the hydraulic system of the working machine 1 according to the present invention will be described with reference to the drawings as appropriate.
[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 6 shows a side view of the working machine according to the present invention. FIG. 6 shows a compact truck loader as an example of a working machine. However, the working machine according to the present invention is not limited to the compact truck loader, and may be, for example, another type of loader working machine such as a skid steering loader. Further, it may be a work machine other than the loader work machine.

As shown in FIGS. 6 and 7, the working machine 1 includes a machine body 2, a cabin 3, a working device 4, and a traveling device 5. In the embodiment of the present invention, the front side (left side of FIG. 6) of the driver seated in the driver's seat 8 of the work machine 1 is the front, the rear side of the driver (right side of FIG. 6) is the rear, and the left side of the driver (FIG. 6). The front side of No. 6) will be described as the left side, and the right side of the driver (the back side of FIG. 6) will be described as the right side. Further, the horizontal direction, which is a direction orthogonal to the front-rear direction, will be described as the body width direction. The direction from the central portion of the aircraft 2 toward the right or left portion will be described as the outer side of the aircraft. In other words, the outside of the airframe is the width direction of the airframe and the direction away from the airframe 2. The direction opposite to the outside of the aircraft will be described as the inside of the aircraft. In other words, the inside of the machine is the width direction of the machine and the direction approaching the body 2.

The cabin 3 is mounted on the airframe 2. The cabin 3 is provided with a driver's seat 8. The working device 4 is attached to the machine body 2. The traveling device 5 is provided on the outside of the machine body 2. A prime mover 32 is mounted on the rear part of the machine body 2.
The working device 4 has a boom 10, a working tool 11, a lift link 12, a control link 13, a boom cylinder 14, and a bucket cylinder 15.

The boom 10 is provided on the right side and the left side of the cabin 3 so as to be vertically swingable. The work tool 11 is, for example, a bucket, and the bucket 11 is provided at the tip end portion (front end portion) of the boom 10 so as to be vertically swingable. The lift link 12 and the control link 13 support the base portion (rear portion) of the boom 10 so that the boom 10 can swing up and down. The boom cylinder 14 expands and contracts to raise and lower the boom 10. The bucket cylinder 15 swings the bucket 11 by expanding and contracting.

The front parts of the left and right booms 10 are connected by a deformed connecting pipe. The bases (rear parts) of the booms 10 are connected to each other by a circular connecting pipe.
The lift link 12, the control link 13, and the boom cylinder 14 are provided on the left side and the right side of the machine body 2, respectively, corresponding to the left and right booms 10.
The lift link 12 is provided vertically at the rear of the base of each boom 10. The upper portion (one end side) of the lift link 12 is rotatably supported around the lateral axis via a pivot shaft (first pivot shaft) 16 near the rear portion of the base of each boom 10. Further, the lower portion (the other end side) of the lift link 12 is rotatably and rotatably supported around the lateral axis via a pivot shaft (second pivot shaft) 17 near the rear portion of the airframe 2. The second pivot shaft 17 is provided below the first pivot shaft 16.

The upper portion of the boom cylinder 14 is rotatably supported around a horizontal axis via a pivot shaft (third pivot shaft) 18. The third pivot shaft 18 is a base portion of each boom 10, and is provided at a front portion of the base portion. The lower portion of the boom cylinder 14 is rotatably supported around a horizontal axis via a pivot shaft (fourth pivot shaft) 19. The fourth pivot shaft 19 is provided near the lower part of the rear portion of the airframe 2 and below the third pivot shaft 18.

The control link 13 is provided in front of the lift link 12. One end of the control link 13 is rotatably supported around a horizontal axis via a pivot shaft (fifth pivot shaft) 20. The fifth pivot shaft 20 is the airframe 2, and is provided at a position corresponding to the front of the lift link 12. The other end of the control link 13 is rotatably supported around a horizontal axis via a pivot shaft (sixth pivot shaft) 21. The sixth pivot shaft 21 is a boom 10 and is provided in front of the second pivot shaft 17 and above the second pivot shaft 17.

By expanding and contracting the boom cylinder 14, each boom 10 swings up and down around the first pivot shaft 16 while the base of each boom 10 is supported by the lift link 12 and the control link 13, and the tip of each boom 10 Goes up and down. The control link 13 swings up and down around the fifth pivot shaft 20 as each boom 10 swings up and down. The lift link 12 swings back and forth around the second pivot shaft 17 as the control link 13 swings up and down.

Another work tool can be attached to the front part of the boom 10 instead of the bucket 11. Another working tool is, for example, an attachment (spare attachment) such as a hydraulic crusher, a hydraulic breaker, an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, or a snow blower.
A connecting member 50 is provided on the front portion of the boom 10 on the left side. The connecting member 50 is a device for connecting the hydraulic device mounted on the spare attachment and the first pipe material such as a pipe provided on the boom 10. Specifically, the first pipe material can be connected to one end of the connecting member 50, and the second pipe material connected to the hydraulic device of the spare attachment can be connected to the other end. As a result, the hydraulic oil flowing through the first pipe material passes through the second pipe material and is supplied to the flood control equipment.

The bucket cylinder 15 is arranged near the front of each boom 10. By expanding and contracting the bucket cylinder 15, the bucket 11 is swung.
As each of the left and right traveling devices 5, a crawler type (including a semi-crawler type) traveling device is adopted in the present embodiment. A wheel-type traveling device having front wheels and rear wheels may be adopted.

Next, the traveling system hydraulic system will be described.
As shown in FIG. 1, the hydraulic system includes a first hydraulic pump P1, a left traveling motor device (first traveling motor device) 31L, a right traveling motor device (second traveling motor device) 31R, a prime mover 32, and the like. It has a traveling drive device 34.
The first hydraulic pump P1 can discharge the hydraulic oil stored in the tank 22. The first hydraulic pump P1 is a drive pump driven by the power of the prime mover 32, and is composed of a constant capacity type gear pump. The first hydraulic pump P1 discharges hydraulic oil mainly used for control. For convenience of explanation, the tank 22 for storing the hydraulic oil may be referred to as a hydraulic oil tank. Further, among the hydraulic oil discharged from the first hydraulic pump P1, the hydraulic oil used for control may be referred to as pilot oil, and the pressure of the pilot oil may be referred to as pilot pressure. An oil passage (discharge oil passage) 40 for flowing hydraulic oil (pilot oil) is provided on the discharge side of the first hydraulic pump P1. The discharge oil passage (first oil passage) 40 is provided with a first traveling motor device 31L and a second traveling motor device 31R.

The prime mover 32 is composed of an electric motor, an engine and the like. In this embodiment, the prime mover 32 is an engine. The prime mover 32 may be a hybrid type having an electric motor and an engine, or may have only an electric motor.
The travel drive device 34 is a device that drives the first travel motor device 31L and the second travel motor device 31R, and is a drive circuit (left drive circuit) 34L for driving the first travel motor device 31L and a second travel. It has a drive circuit (right drive circuit) 34R for driving the motor device 31R.

The left drive circuit 34L and the right drive circuit 34R have traveling pumps (traveling hydraulic pumps) 53L and 53R, transmission oil passages 57h and 57i, and a second charge oil passage 57j, respectively. The shifting oil passages 57h and 57i are oil passages that connect the traveling pumps 53L and 53R and the traveling motor 36. The second charge oil passage 57j is an oil passage that is connected to the transmission oil passages 57h and 57i and replenishes the hydraulic oil from the first hydraulic pump P1 to the transmission oil passages 57h and 57i.

The traveling pumps 53L and 53R are swash plate type variable displacement axial pumps driven by the power of the prime mover 32. In other words, the traveling pumps 53L and 53R are traveling actuators that can be operated by hydraulic oil. The traveling pumps 53L and 53R have a forward pressure receiving portion 53a on which a pilot pressure acts and a reverse pressure receiving portion 53b. The angle of the swash plate is changed by the pilot pressure acting on the forward pressure receiving portion 53a and the reverse pressure receiving portion 53b. By changing the angle of the slab, the output (discharge amount of hydraulic oil) of the traveling pumps 53L and 53R and the discharge direction of the hydraulic oil can be changed.

The first traveling motor device 31L is a motor that transmits power to the drive shaft of the traveling device 5 provided on the left side of the machine body 2. The second traveling motor device 31R is a motor that transmits power to the drive shaft of the traveling device 5 provided on the right side of the machine body 2.
The first traveling motor device 31L includes a traveling motor 36, a front-rear switching valve 35, and a traveling control valve (flood control valve) 38. Hydraulic oil can be supplied to the traveling motor 36, the front / rear switching valve 35, and the traveling control valve 38.

The traveling motor 36 is a cam motor (radial piston motor). The traveling motor 36 changes the rotation and torque of the output shaft by changing the size of the capacity (motor capacity) during operation.
Next, the work system hydraulic system will be described.
As shown in FIG. 2, the hydraulic system includes a plurality of control valves 56 and a working system hydraulic pump (second hydraulic pump) P2.

The second hydraulic pump P2 is a pump installed at a position different from that of the first hydraulic pump P1, and is composed of a constant-capacity gear pump. The second hydraulic pump P2 can discharge the hydraulic oil stored in the tank 22. The second hydraulic pump P2 mainly discharges hydraulic oil that operates the hydraulic actuator.
An oil passage (main oil passage) 39 is provided on the discharge side of the second hydraulic pump P2. A plurality of control valves 56 are connected to the main oil passage 39. The control valve 56 is a valve capable of switching the flow direction of the hydraulic oil by the pilot pressure of the pilot oil. Further, the control valve 56 controls (drives) a hydraulic device such as a boom, a bucket, a hydraulic crusher, a hydraulic breaker, an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, and a snow blower.

The plurality of control valves 56 are a first control valve 56A, a second control valve 56B, and a third control valve 56C. The first control valve 56A is a valve that controls the hydraulic cylinder (boom cylinder) 14 that controls the boom. The second control valve 56B is a valve that controls the hydraulic cylinder (bucket cylinder) 15 that controls the bucket. The third control valve 56C is a valve that controls hydraulic equipment (hydraulic cylinder, hydraulic motor) attached to spare attachments such as a hydraulic crusher, a hydraulic breaker, an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, and a snow blower. be. In the following description, the first control valve 56A may be referred to as a boom control valve. Further, the second control valve 56B may be referred to as a bucket control valve.

The first control valve 56A and the second control valve 56B are pilot-type direct-acting spool-type three-position switching valves, respectively. The first control valve 56A and the second control valve 56B are switched to the neutral position, the first position different from the neutral position, the neutral position, and the second position different from the first position by the pilot pressure. The first control valve 56A can be operated by the pressure difference of the hydraulic oil acting on the pressure receiving portions on one side and the other side of the first control valve 56A. Further, the second control valve 56B can be operated by the pressure difference of the hydraulic oil acting on the pressure receiving portions on one side and the other side of the second control valve 56B. A boom cylinder 14 is connected to the first control valve 56A via an oil passage, and a bucket cylinder 15 is connected to the second control valve 56B via an oil passage.

An oil supply / drainage passage 83 is connected to the third control valve 56C. One end of the oil supply / drainage passage 83 is connected to the supply / discharge port of the third control valve 56C, the middle part of the oil supply / discharge passage 83 is connected to the connecting member 50, and the other end of the oil supply / discharge passage 83 is. Connected to the hydraulic equipment of the spare attachment. Specifically, the oil supply / drainage passage 83 includes a first oil supply / discharge passage 83a that connects the first supply / discharge port of the third control valve 56C and the first port of the connecting member 50. Further, the oil supply / drainage passage 83 includes a second oil supply / discharge passage 83b that connects the second supply / discharge port of the third control valve 56C and the second port of the connecting member 50. That is, by operating the third control valve 56C, hydraulic oil can flow from the third control valve 56C toward the first oil supply / drainage passage 83a, or from the third control valve 56C toward the second oil supply / discharge passage 83b. The hydraulic oil can be flushed.

As shown in FIGS. 1 and 2, the operation related to the running of the work machine 1 (running operation) and the operation related to the work (work operation) are performed by the first operation device 47 provided to the left of the driver's seat 8 and the driver's seat 8. This is performed by the second operating device 48 provided on the right side of the above. In other words, the first operating device 47 and the second operating device 48 are a traveling system hydraulic device (traveling motor 36, traveling pump 53L, 53R) and a working system hydraulic device (first control valve 56A, second control valve 56B). , Third control valve 56C, boom cylinder 14, bucket cylinder 15, hydraulic cylinder provided in the spare attachment, hydraulic motor).

Next, the first operating device 47 and the second operating device 48 will be described in detail.
The first operating device 47 is a device capable of performing both a traveling operation and a working operation, and has a first operating member 54. The first operating member 54 is a lever capable of performing a first operation of moving back and forth and a second operation of moving left and right (in the width direction of the machine body) different from the front and back. In other words, the first operating member 54 is a lever that can be moved in one direction (for example, front, left) and in another direction (for example, rear, right) different from one direction.

In the first operation member 54, the first operation is assigned to the traveling operation, and the second operation is assigned to the work operation. That is, the first operating member 54 also serves as a traveling operating member (traveling operating member) and a working operating member (working operating member). The first operation member 54 is not limited to the lever as long as at least the first operation and the second operation can be performed independently.

A plurality of pilot valves 55 are provided below the first operating member 54. The plurality of pilot valves 55 can change the pressure of the hydraulic oil according to the operation of the first operating member 54. More specifically, the pilot valve 55 has a rod that comes into contact with the first operating member 54. That is, the pressure of the hydraulic oil output from the pilot valve 55 is changed by pushing the rod in response to the operation of the first operating member 54. The plurality of pilot valves 55 are a pilot valve 55A, a pilot valve 55B, a pilot valve 55C, and a pilot valve 55D. The pilot valve 55A, the pilot valve 55B, the pilot valve 55C, and the pilot valve 55D are connected to the discharge oil passage 40.

The pilot valve 55A is a valve that is operated by the pre-operation in the first operation (front-rear operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the pre-operation. The pilot valve 55B is a valve that is operated by a rear operation in the first operation (front and rear operations), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the rear operation. That is, the pilot valve 55A and the pilot valve 55B are valves that are operated by the first operation, and move in response to the traveling operation.

The pilot valve 55C is a valve that operates by the left operation of the second operation (left and right operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the left operation. The pilot valve 55D is a valve that operates by the right operation in the second operation (left and right operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the right operation. That is, the pilot valve 55C and the pilot valve 55D are valves that are operated by the second operation, and move in response to the work operation.

The second operating device 48 is a device capable of performing both a traveling operation and a working operation, and has a second operating member 58. The second operating member 58 is a lever capable of performing a first operation of moving back and forth and a second operation of moving left and right (in the width direction of the machine body) different from the front and back. In other words, the second operating member 58 is a lever that can be moved in one direction (for example, front, left) and in another direction (for example, rear, right) different from one direction.

In the second operation member 58, the first operation is assigned to the traveling operation, and the second operation is assigned to the work operation. That is, the second operating member 58 also serves as a traveling operating member (traveling operating member) and a working operating member (working operating member). The second operating member 58 is not limited to the lever as long as at least the first operation and the second operation can be performed independently.

A plurality of pilot valves 59 are provided below the second operating member 58. The plurality of pilot valves 59 can change the pressure of the hydraulic oil according to the operation of the second operating member 58. More specifically, the pilot valve 59 has a rod that comes into contact with the second operating member 58. That is, the pressure of the hydraulic oil output from the pilot valve 59 is changed by pushing the rod in response to the operation of the second operating member 58. The plurality of pilot valves 59 are a pilot valve 59A, a pilot valve 59B, a pilot valve 59C, and a pilot valve 59D. The pilot valve 59A, the pilot valve 59B, the pilot valve 59C, and the pilot valve 59D are connected to the discharge oil passage 40.

The pilot valve 59A is a valve that is operated by the pre-operation of the second operation (front-rear operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the pre-operation. The pilot valve 59B is a valve that is operated by a rear operation in the first operation (front and rear operations), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the rear operation. That is, the pilot valve 59A and the pilot valve 59B are valves that are operated by the first operation, and move in response to the traveling operation.

The pilot valve 59C is a valve that operates by the left operation in the first operation (left and right operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the left operation. The pilot valve 59D is a valve that operates by the right operation in the second operation (left and right operation), and the pressure of the hydraulic oil to be output changes according to the operation amount (operation) of the right operation. That is, the pilot valve 59C and the pilot valve 59D are valves that are operated by the second operation, and move in response to the work operation.

From the above, among the plurality of pilot valves, the pilot valve 55A, the pilot valve 55B, the pilot valve 59A, and the pilot valve 59B operate in response to the traveling operation, and the pilot valve 55C, the pilot valve 55D, the pilot valve 59C, The pilot valve 59D operates in response to a work operation. For convenience of explanation, the pilot valve 55A, the pilot valve 55B, the pilot valve 59A, and the pilot valve 59B may be referred to as a traveling pilot valve. Of the traveling pilot valves, the pilot valve 55A that operates in one direction (for example, front) of the first operating member 54 is called a "first pilot valve", and is referred to as a "first pilot valve" in the other direction (for example, rear) of the first operating member 54. The pilot valve 55B operated by is called a "second pilot valve", and the pilot valve 59A operated by one direction (for example, front) of the second operating member 58 is called a "third pilot valve". 2 The pilot valve 59B that operates in the other direction (for example, rearward) of the operating member 58 is referred to as a "fourth pilot valve".

Next, the relationship with the traveling pilot valve, the working pilot valve, and the hydraulic equipment will be described. Reference numerals "W1", "W2", "D1", and "D2" shown in FIGS. 1 and 2 indicate connection destinations of oil passages.
The traveling pilot valve and the traveling pumps 53L and 53R, which are one of the traveling hydraulic equipment (traveling hydraulic equipment), are connected by a traveling oil passage 45. The traveling oil passage 45 has a first traveling oil passage 45a, a second traveling oil passage 45b, a third traveling oil passage 45c, and a fourth traveling oil passage 45d. The first traveling oil passage 45a is an oil passage connecting the first pilot valve 55A and the forward pressure receiving portion 53a of the traveling pump 53L. The second traveling oil passage 45b is an oil passage connecting the second pilot valve 55B and the reverse pressure receiving portion 53b of the traveling pump 53L. The third traveling oil passage 45c is an oil passage connecting the third pilot valve 59A and the forward pressure receiving portion 53a of the traveling pump 53R. The fourth traveling oil passage 45d is an oil passage connecting the fourth pilot valve 59B and the reverse pressure receiving portion 53b of the traveling pump 53R.

When the first operating member 54 is tilted forward, the first pilot valve 55A is operated and the pilot pressure is output from the first pilot valve 55A. This pilot pressure acts on the forward pressure receiving portion 53a of the traveling pump 53L. When the second operating member 58 is tilted forward, the third pilot valve 59A is operated and the pilot pressure is output from the third pilot valve 59A. This pilot pressure acts on the forward pressure receiving portion 53a of the traveling pump 53R.

When the first operating member 54 is tilted to the rear side, the second pilot valve 55B is operated and the pilot pressure is output from the second pilot valve 55B. This pilot pressure acts on the reverse pressure receiving portion 53b of the traveling pump 53L. When the second operating member 58 is tilted to the rear side, the fourth pilot valve 59B is operated and the pilot pressure is output from the fourth pilot valve 59B. This pilot pressure acts on the reverse pressure receiving portion 53b of the traveling pump 53R.

Therefore, when the first operating member 54 and the second operating member 58 are swung forward, the traveling motor (HST motor) 36 is positive at a speed proportional to the swing amount of the first operating member 54 and the second operating member 58. As a result, the working machine 1 goes straight forward. When the first operating member 54 and the second operating member 58 are swung rearward, the traveling motor 36 reverses at a speed proportional to the swing amount of the first operating member 54 and the second operating member 58, resulting in the result. , The working machine 1 goes straight backward.

Further, when one of the first operating member 54 and the second operating member 58 swings forward and the other swings backward, the left traveling motor 36 and the right traveling motor 36 move in different directions. Rotation, as a result, the working machine 1 turns to the right or left.
As described above, by moving the first operation member 54 back and forth and the second operation member 58 back and forth, it is possible to perform a traveling operation for moving the work machine 1 forward, backward, right turn, and left turn.

Further, the work pilot valve and the control valve 56, which is one of the work system hydraulic equipment (work hydraulic equipment), are connected by a work oil passage 46. The working oil passage 46 has a first working oil passage 46a, a second working oil passage 46b, a third working oil passage 46c, and a fourth working oil passage 46d. The first working oil passage 46a is an oil passage that connects the pilot valve 55C and the pressure receiving portion of the first control valve 56A. The second working oil passage 46b is an oil passage that connects the pilot valve 55D and the pressure receiving portion of the first control valve 56A. The third working oil passage 46c is an oil passage that connects the pilot valve 59C and the pressure receiving portion of the second control valve 56B. The fourth working oil passage 46d is an oil passage that connects the pilot valve 59D and the pressure receiving portion of the second control valve 56B.

When the first operating member 54 is tilted to the left, the pilot valve 55C is operated and the pilot pressure of the pilot oil output from the pilot valve 55C is set. This pilot pressure acts on the pressure receiving portion of the first control valve 56A, the boom cylinder 14 extends, and the boom 10 rises. When the first operating member 54 is tilted to the right, the pilot valve 55D is operated to set the pilot pressure of the pilot oil output from the pilot valve 55D. This pilot pressure acts on the pressure receiving portion of the first control valve 56A, the boom cylinder 14 contracts, and the boom 10 descends. When the second operating member 58 is tilted to the left, the pilot valve 59C is operated and the pilot pressure of the pilot oil output from the pilot valve 59C is set. This pilot pressure acts on the pressure receiving portion of the second control valve 56B, the bucket cylinder 15 contracts, and the bucket 11 squeezes. When the second operating member 58 is tilted to the right, the pilot valve 59D is operated and the pilot pressure of the pilot oil output from the pilot valve 59D is set. This pilot pressure acts on the pressure receiving portion of the second control valve 56B, the bucket cylinder 15 extends, and the bucket 11 dumps.

Therefore, by moving the first operating member 54 to the left or right or moving the second operating member 58 to the left or right, it is possible to perform work operations such as raising and lowering the boom 10, dumping the bucket, or squeezing.
By the way, the hydraulic system includes a hydraulic pump, a first hydraulic device, a second hydraulic device, an operating member, and an operating valve. In the present embodiment, the hydraulic pump is the first hydraulic pump P1. The first hydraulic device is the second control valve 56B. The second hydraulic device is the first control valve 56A. The operating member is the second operating member 58. The operating valves are pilot valves 59C and 59D. The hydraulic system also has a supply oil passage. In the present embodiment, the supply oil passages are the third working oil passage 46c connecting the pilot valve 59C and the second control valve 56B, and the fourth working oil passage 46d connecting the pilot valve 59D and the second control valve 56B. .. The second control valve 56B has a first pressure receiving unit 76a and a second pressure receiving unit 76b, and can be operated by the pressure difference of the hydraulic oil acting on the first pressure receiving unit 76a and the second pressure receiving unit 76b, respectively. .. Specifically, the third working oil passage 46c is connected to the first pressure receiving portion 76a. The fourth working oil passage 46d is connected to the first pressure receiving portion 76b. That is, the second control valve 56B has a first position, a neutral position, and a first position different from the neutral position and the neutral position due to the pressure difference of the pilot pressure of the hydraulic oil acting on the first pressure receiving portion 76a and the second pressure receiving portion 76b. It switches to a second position that is different from the position.

The hydraulic system has a branch oil passage 64 and a solenoid valve 65. The branch oil passage 64 includes a first branch oil passage 64a that joins the third working oil passage 46c and a second branch oil passage 64b that joins the fourth working oil passage 46d.
The solenoid valve 65 is an electromagnetic proportional valve (proportional valve) whose opening degree can be changed by exciting a solenoid. That is, the solenoid valve 65 can change the flow rate of the hydraulic oil passing through. The solenoid valve 65 includes a first solenoid valve 65a connected to the first branch oil passage 64a and a second solenoid valve 65b connected to the second branch oil passage 64b. The solenoid valve 65 is connected to the first hydraulic pump P1 on the inlet side and to the branch oil passage 64 on the outlet side. More specifically, the first solenoid valve 65a is connected to the first branch oil passage 64a on the outlet side. The outlet side of the second solenoid valve 65b is connected to the second branch oil passage 64b. According to the solenoid valve 65, when the opening degree is changed from the fully closed state, the working oil passages 46c and 46d are connected to the first hydraulic pump P1. That is, hydraulic oil can be applied to the second control valve 56B from the hydraulic pump P1 via the solenoid valve 65. Specifically, the hydraulic oil discharged by the first hydraulic pump P1 can be merged into the working oil passages 46c and 46d via the solenoid valve 65 and the branch oil passage 64, respectively. As a result, the hydraulic oil discharged by the hydraulic pump P1 can act on the second control valve 56B.

The hydraulic system includes a change section 51. The changing unit 51 can be changed to a first state in which either the pilot valves 59C, 59D and the solenoid valve 65 are operated, and a second state in which both the pilot valves 59C, 59D and the solenoid valve 65 are operated. be. The change section 51 has shuttle valves 85 and 86. The shuttle valve 85 is provided at the confluence 66 of the work oil passage 46 and the branch oil passage 64. The shuttle valve 86 is provided in the second merging portion 66b where the fourth working oil passage 46d and the second branch oil passage 64b meet.

When either the pilot valve 59C or the solenoid valve 65 is activated (in the first state), the shuttle valve 85 sets the pressure of the hydraulic oil set by the activated pilot valve 59C or the solenoid valve 65 to the first. It is transmitted to the pressure receiving unit 76a.
When either the pilot valve 59D or the solenoid valve 65 is activated (in the first state), the shuttle valve 86 applies the pressure of the hydraulic oil set by the activated pilot valve 59D or the solenoid valve 65 to the second. It is transmitted to the pressure receiving unit 76b.

When both the pilot valve 59C and the solenoid valve 65 are activated (in the second state), the shuttle valve 85 applies a higher hydraulic oil pressure among the operated pilot valve 59C or the solenoid valve 65. It is transmitted to the first pressure receiving unit 76a.
When both the pilot valve 59D and the solenoid valve 65 are activated (in the second state), the shuttle valve 85 applies the higher hydraulic oil pressure of the operated pilot valve 59D or the solenoid valve 65 to the second state. It is transmitted to the pressure receiving unit 76b.

Therefore, in the first state, the changing unit 51 sets the hydraulic oil pressure set by the operating valves 59C and 59D or the hydraulic oil pressure set by the solenoid valve 65 to the control valve 56 and the like. It can be applied to one hydraulic device to operate the first hydraulic device. On the other hand, when the changing unit 51 is in the second state, either the hydraulic oil pressure set by the operating valves 59C and 59D or the hydraulic oil pressure set by the solenoid valve 65 is set by the control valve 56 or the like. It can be applied to the first hydraulic device to operate the first hydraulic device.

Further, the changing unit 51 includes a control device 90. The control device 90 controls the solenoid valve 65. The control device 90 is composed of a CPU and the like, and performs various processes related to the device connected to the control device 90. Specifically, the control device 90 is connected to the angle detection unit 91 that detects the angle of the boom 10. The control device 90 can be switched to the horizontal control mode. The horizontal control mode is a mode in which the angle of the bucket 11 is kept constant even if the operator does not operate the second operating member 58. Switching to the horizontal control mode is performed by a switch 92 connected to the control device 90. The switch 92 is a member that instructs the control device 90 to switch to the horizontal control mode. When the switch 92 is pressed, a signal is output to the control device 90 to switch to the horizontal control mode. On the other hand, when the switch 92 is pressed again, the horizontal control mode is released. The switch 92 is a push button switch 92 such as a momentary switch or an alternate switch. The switch 92 is not limited to the push button switch 92 of the momentary switch or the alternate switch, and may be any switch 92 that outputs a signal to the control device 90.

When the horizontal control mode is released, the pilot valves 59C and 59D act on the second control valve 56B with hydraulic oil. Further, the control device 90 closes the solenoid valve 65. On the other hand, when the mode shifts to the horizontal control mode, the control device 90 controls the solenoid valve 65 to act hydraulic oil on the second control valve 56B from the solenoid valve 65. In other words, either one of the hydraulic oil of the pilot valves 59C and 59D and the hydraulic oil of the solenoid valve 65 acts on the second control valve 56B which is the first hydraulic device.

In the horizontal control mode, the control device 90 operates the bucket 11 according to the boom angle detected by the angle detection unit 91. In other words, the control device 90 controls the solenoid valve 65 in response to the movement of the first control valve 56A, which is the second hydraulic device connected to the boom cylinder 14. For example, the bucket angle is controlled based on the moving angle of the boom 10 from the transition to the horizontal control mode. Specifically, when the boom cylinder 14 contracts and the boom 10 descends, the control device 90 controls the solenoid valve 65 so that the bucket 11 squeezes by the same value as the moving angle of the boom 10. On the other hand, when the boom cylinder 14 is extended and the boom 10 is raised, the control device 90 controls the solenoid valve 65 so that the bucket 11 dumps by the same value as the moving angle of the boom 10. That is, the bucket 11 is horizontally controlled. That is, the control device 90 controls the solenoid valve 65 according to the operation of the first control valve 56A. Thereby, the moving angle of the bucket 11 connected to the second control valve 56B can be controlled according to the moving angle of the boom 10 connected to the first control valve 56A via the boom cylinder 14. Therefore, since the above-described configuration is simple and can be removed, the horizontal control function of the bucket 11 can be introduced into the hydraulic system of the work machine 1. The bucket 11 may be operated according to the moving angle of the boom 10, and a detection device for measuring the extension / contraction distance of the boom cylinder 14 may be provided instead of the angle detection unit 91. Further, a pressure sensor is provided in the working oil passage 46, and the control device 90 controls the first solenoid valve 65a and the second solenoid valve 65b based on the pressure of the hydraulic oil output from the operating valves 59C and 59D. You may go.

The shuttle valves 85 and 86 include a first shuttle valve 85 and a second shuttle valve 86. The merging portion 66 includes a first merging portion 66a and a second merging portion 66b.
The first shuttle valve 85 is provided at the first merging portion 66a where the third working oil passage 46c and the first branch oil passage 64a meet. The first shuttle valve 85 communicates with the pilot valve 59C and the second control valve 56B, and regulates the hydraulic oil between the first solenoid valve 65a and the second control valve 56B, and the pilot valve 59C and the second. It regulates hydraulic oil with the control valve 56B and has a second position for communicating the first solenoid valve 65a and the second control valve 56B. That is, when the pressure of the hydraulic oil acting on the first shuttle valve 85 from the pilot valve 59C is larger than the pressure of the hydraulic oil acting on the first shuttle valve 85 from the first solenoid valve 65a, it is set by the pilot valve 59C. The pressure of the hydraulic oil acts on the first pressure receiving portion 76a. In such a case, the hydraulic oil acting on the first solenoid valve 65a to the first shuttle valve 85 does not apply pressure to the first pressure receiving portion 76a. On the other hand, when the pressure of the hydraulic oil acting from the first solenoid valve 65a to the first shuttle valve 85 is larger than the pressure of the hydraulic oil acting from the pilot valve 59C to the first shuttle valve 85, the first solenoid valve 65a is used. The set hydraulic oil pressure acts on the first pressure receiving portion 76a. In such a case, the hydraulic oil acting on the first shuttle valve 85 from the pilot valve 59C does not apply pressure to the first pressure receiving portion 76a.

The second shuttle valve 86 is provided in the second merging portion 66b where the fourth working oil passage 46d and the second branch oil passage 64b meet. The second shuttle valve 86 communicates with the pilot valve 59D and the second control valve 56B, and regulates the hydraulic oil between the second solenoid valve 65b and the second control valve 56B, and the pilot valve 59D and the second. It regulates hydraulic oil with the control valve 56B and has a second position for communicating the second solenoid valve 65b and the second control valve 56B. That is, when the pressure of the hydraulic oil acting on the second shuttle valve 86 from the pilot valve 59D is larger than the pressure of the hydraulic oil acting on the second shuttle valve 86 from the second solenoid valve 65b, it is set by the pilot valve 59D. The pressure of the hydraulic oil acts on the second pressure receiving portion 76b. In such a case, the hydraulic oil acting on the second solenoid valve 65b to the second shuttle valve 86 does not apply pressure to the second pressure receiving portion 76b. On the other hand, when the pressure of the hydraulic oil acting on the second shuttle valve 86 from the second solenoid valve 65b is larger than the pressure of the hydraulic oil acting on the second shuttle valve 86 from the pilot valve 59D, the second solenoid valve 65b The set hydraulic oil pressure acts on the second pressure receiving portion 76b. In such a case, the hydraulic oil acting on the second shuttle valve 86 from the pilot valve 59D does not apply pressure to the second pressure receiving portion 76b. As a result, the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64, whichever has the higher pressure, can act on the second control valve 56B. On the other hand, the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64 can prevent the hydraulic oil having the lower pressure from acting on the second control valve 56B. Therefore, either one of the pilot valves 59C and 59D and the solenoid valve 65 can act on the second control valve 56B.

Between the outlet side of the first shuttle valve 85 and the first pressure receiving portion 76a in the third working oil passage 46c, and between the outlet side of the second shuttle valve 86 and the second pressure receiving portion 76b in the fourth working oil passage 46d. And, respectively, are provided with a bypass check valve 96. The bypass check valve 96 allows the flow of hydraulic oil from the pilot valves 59C and 59D to the second control valve 56B and blocks the flow of hydraulic oil from the second control valve 56B to the pilot valves 59C and 59D. Bypass oil passages 95 are provided on the inlet and outlet sides of the bypass check valve 96, and throttles 97 are provided in the bypass oil passages 95. The throttle 97 reduces the flow rate of hydraulic oil. The throttle 97 is configured by, for example, making a part of the bypass oil passage 95 thinner than the other parts. In other words, it is configured by making the cross-sectional area of the portion of the bypass oil passage 95 through which the hydraulic oil flows smaller than that of the other portions. The above configuration may be applied to a traveling system hydraulic system.

FIG. 3 shows a first modification of the first embodiment. The work oil passage 46 has a first check valve 71 and a second check valve 72. The first check valve 71 is provided in the working oil passages 46c and 46d between the merging portion 66 between the working oil passages 46c and 46d and the branch oil passage 64 and the pilot valves 59C and 59D. That is, the first check valve 71 is provided in each of the third working oil passage 46c and the fourth working oil passage 46d. Specifically, the first check valve 71 allows the flow of hydraulic oil from the pilot valves 59C and 59D toward the confluence 66, and allows the flow of hydraulic oil from the confluence 66 toward the pilot valves 59C and 59D. regulate.

On the other hand, the second check valve 72 is provided in the first branch oil passage 64a connected to the third working oil passage 46c and the second branch oil passage 64b connected to the fourth working oil passage 46d, respectively. There is. The second check valve 72 allows the flow of hydraulic oil from the solenoid valve 65 toward the confluence 66, and regulates the flow of hydraulic oil from the confluence 66 toward the solenoid valve 65. As a result, the hydraulic oil flowing from the pilot valves 59C and 59D sides toward the second control valve 56B side is allowed, and the hydraulic oil flowing from the second control valve 56B and the solenoid valve 65 side toward the pilot valves 59C and 59D side is allowed. It can be stopped. Further, the hydraulic oil flowing from the solenoid valve 65 side toward the second control valve 56B side is allowed, and the hydraulic oil flowing from the second control valve 56B and the pilot valves 59C and 59D side toward the solenoid valve 65 side is blocked. Can be done. Therefore, it is possible to prevent the backflow of hydraulic oil from the second control valve 56B and the solenoid valve 65 side to the pilot valves 59C and 59D. Further, it is possible to prevent the backflow of hydraulic oil from the second control valve 56B and the pilot valves 59C and 59D to the solenoid valve 65. In the above-described modification, the second control valve 56B may be operated only by operating the second operating member 58, or the second control valve 56B may be operated only by controlling the control device 90. Further, the second control valve 56B may be operated by operating both the second operating member 58 and the control device 90.

FIG. 4 shows a second modification of the first embodiment. The inlet side of the first solenoid valve 65a is connected to the second working oil passage 46b, and the outlet side is connected to the branch oil passage 64a. That is, in the horizontal control mode, when the control device 90 opens the first solenoid valve 65a from the closure, the hydraulic oil output from the pilot valve 55D passes through the second working oil passage 46b and the first solenoid valve 65a. It flows into the branch oil passage 64a. In this case, the operations of the boom cylinder 14 and the bucket cylinder 15 will be described in detail. The hydraulic oil output from the pilot valve 55D acts on the pressure receiving portion of the first control valve 56A, the boom cylinder 14 contracts, and the boom occurs. 10 descends. Further, the hydraulic oil output by the pilot valve 55D acts on the first pressure receiving portion 76a of the second control valve 56B, the bucket cylinder 15 contracts, and the bucket 11 squeezes. That is, according to the above configuration, the control device 90 controls the opening degree of the first solenoid valve 65a, so that the squeeze operation of the bucket 11 can be controlled according to the lowering of the boom 10. That is, the bucket 11 can be controlled horizontally.

The hydraulic system of the work machine 1 described above includes a hydraulic pump P1, a first hydraulic device 56B, an operating member 58, operating valves 59C and 59D, a solenoid valve 65, a control device 90, and a changing unit 51. I have. As a result, the first hydraulic device 56B can be made to act on the hydraulic oil from two different systems of the operating valves 59C and 59D and the solenoid valve 65. Therefore, apart from the operation of the operation member 58 by the operator, the control device 90 opens the solenoid valve 65 and causes the hydraulic oil to act on the first hydraulic device 56B, so that the first flood control device 56B can be easily operated. Can be done.

Further, the hydraulic system of the work machine 1 includes a second hydraulic device 56A, and the control device 90 controls the solenoid valve 65 according to the operation of the second hydraulic device 56A. Thereby, the operating angle of the hydraulic device 15 connected to the first hydraulic device 56B can be controlled according to the operating angle of the hydraulic device 14 connected to the second hydraulic device 56A. Therefore, since the above-described configuration is simple and removable, the horizontal control function can be introduced into the hydraulic system of the work machine 1.

Further, the hydraulic system of the work machine 1 includes supply oil passages 46c and 46d and branch oil passages 64. As a result, hydraulic oil is supplied to the first hydraulic device 56B from two different oil passages, that is, the supply oil passages 46c and 46d to which the operation valves 59C and 59D are connected and the branch oil passage 64 provided with the solenoid valve 65. Can act. Therefore, apart from the operation of the operation member 58 by the operator, the control device 90 opens the solenoid valve 65 and causes the hydraulic oil to act on the first hydraulic device 56B via the branch oil passage 64, so that the first one can be easily performed. The hydraulic device 56B can be operated.

Further, the change section 51 includes shuttle valves 85 and 86. As a result, the hydraulic oil flowing through the supply oil passages 46c and 46d and the hydraulic oil flowing through the branch oil passage 64 can act on the first hydraulic device 56B with the hydraulic oil having the higher pressure. On the other hand, the hydraulic oil in the supply oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64 can prevent the flow of the hydraulic oil having the lower pressure. Therefore, either one of the operation valves 59C and 59D and the solenoid valve 65 can act on the first hydraulic device 56B.

Further, the flood control system of the working machine 1 includes a first check valve 71 and a second check valve 72. As a result, the hydraulic oil flowing from the operation valves 59C and 59D sides toward the first hydraulic equipment 56B side is allowed, and the hydraulic oil flowing from the first hydraulic equipment 56B and the solenoid valve 65 side toward the operation valves 59C and 59D side is allowed. It can be stopped. Further, the hydraulic oil flowing from the solenoid valve 65 side toward the first hydraulic device 56B side is allowed, and the hydraulic oil flowing from the first hydraulic device 56B and the operation valves 59C and 59D side toward the solenoid valve 65 side is blocked. Can be done. Therefore, it is possible to prevent the backflow of hydraulic oil from the first hydraulic device 56B and the solenoid valve 65 side to the operating valves 59C and 59D. Further, it is possible to prevent the backflow of hydraulic oil from the first hydraulic device 56B and the operation valves 59C and 59D to the solenoid valve 65.

The first hydraulic device 56B is a bucket control valve 56B, and the second flood control device 56A is a boom control valve 56A. Thereby, the operating angle of the bucket 11 connected to the bucket control valve 56B is controlled via the bucket cylinder 15 according to the operating angle of the boom 10 connected to the boom control valve 56A via the boom cylinder 14. Can be done. Therefore, since the above-described configuration is simple and removable, the horizontal control function can be introduced into the hydraulic system of the work machine 1.
[Second Embodiment]
FIG. 5 shows a hydraulic system according to a second embodiment of the present invention. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

Now, the hydraulic system includes a hydraulic pump, a first hydraulic device, an operating member, and an operating valve. In the present embodiment, the hydraulic pump is the first hydraulic pump P1. The first hydraulic equipment is a first control valve 56A and a second control valve 56B. The operating members are a first operating member 54 and a second operating member 58. The operating valves are pilot valves 55C, 55D, 59C, 59D. The hydraulic system also has a supply oil passage. In the present embodiment, the supply oil passages include a working oil passage 46a connecting the pilot valve 55C and the first control valve 56A, a second working oil passage 46b connecting the pilot valve 55D and the first control valve 56A, and a pilot valve. A third working oil passage 46c connecting the 59C and the second control valve 56B, and a fourth working oil passage 46d connecting the pilot valve 59D and the second control valve 56B. The first control valve 56A has a first pressure receiving portion 75a and a second pressure receiving portion 75b, and can be operated by the pressure difference of the hydraulic oil acting on the first pressure receiving portion 75a and the second pressure receiving portion 75b, respectively. be. Specifically, the first working oil passage 46a is connected to the first pressure receiving portion 75a. The second working oil passage 46b is connected to the second pressure receiving portion 75b. That is, the first control valve 56B has a first position, a neutral position, and a first position different from the neutral position and the neutral position due to the pressure difference of the pilot pressure of the hydraulic oil acting on the first pressure receiving portion 75a and the second pressure receiving portion 75b. It switches to a second position that is different from the position.

The branch oil passage 64 includes a third branch oil passage 64c that joins the first working oil passage 46a and a fourth branch oil passage 64d that joins the second working oil passage 46b.
The solenoid valve 65 includes a third solenoid valve 65c connected to the third branch oil passage 64c and a fourth solenoid valve 65d connected to the fourth branch oil passage 64d. The outlet side of the third solenoid valve 65c is connected to the third branch oil passage 64c. The outlet side of the fourth solenoid valve 65d is connected to the fourth branch oil passage 64d. According to the solenoid valve 65, when the opening degree is changed from the fully closed state, the working oil passages 46a and 46b are connected to the first hydraulic pump P1. That is, the hydraulic pump P1 can act on the first control valve 56A via the solenoid valve 65. Specifically, the hydraulic oil discharged by the hydraulic pump P1 can act on the working oil passages 46a and 46b via the solenoid valve 65 and the branch oil passage 64. As a result, the hydraulic oil discharged by the hydraulic pump P1 can act on the first control valve 56A.

The change unit 51 has shuttle valves 87 and 88. The shuttle valves 87 and 88 are provided at the confluence 66 of the working oil passages 46a and 46b and the branch oil passage 64, and communicate the pilot valves 55C and 55D with the first control valve 56A to communicate the solenoid valves 65 and the first. The first position that regulates the hydraulic oil with the control valve 56A and the second position that regulates the hydraulic oil between the pilot valves 55C and 55D and the first control valve 56A and communicates the solenoid valve 65 and the first control valve 56A. And have. More specifically, the shuttle valves 87 and 88 include a third shuttle valve 87 and a fourth shuttle valve 88. The merging portion 66 includes a third merging portion 66c and a fourth merging portion 66d.

The third shuttle valve 87 is provided in the third confluence portion 66c where the first working oil passage 46a and the third branch oil passage 64c meet. The third shuttle valve 87 communicates with the pilot valve 55C and the first control valve 56A, and regulates the hydraulic oil between the third solenoid valve 65c and the first control valve 56A, and the pilot valve 55C and the first. It regulates hydraulic oil with the control valve 56A and has a second position for communicating the third solenoid valve 65c and the first control valve 56A. That is, when the pressure of the hydraulic oil acting on the third shuttle valve 87 from the pilot valve 55C is larger than the pressure of the hydraulic oil acting on the third shuttle valve 87 from the third solenoid valve 65c, it is set by the pilot valve 55C. The pressure of the hydraulic oil acts on the first pressure receiving portion 75a. In such a case, the hydraulic oil acting on the third solenoid valve 65c to the third shuttle valve 87 does not apply pressure to the first pressure receiving portion 75a. On the other hand, when the pressure of the hydraulic oil acting on the third solenoid valve 65c to the third shuttle valve 87 is larger than the pressure of the hydraulic oil acting on the third shuttle valve 87 from the pilot valve 55C, the third solenoid valve 65c is used. The set hydraulic oil pressure acts on the first pressure receiving portion 75a. In such a case, the hydraulic oil acting on the third shuttle valve 87 from the pilot valve 55C does not apply pressure to the first pressure receiving portion 75a.

The fourth shuttle valve 88 is provided at the fourth merging portion 66d where the second working oil passage 46b and the fourth branch oil passage 64c meet. The fourth shuttle valve 88 communicates the pilot valve 55D and the first control valve 56A, and regulates the hydraulic oil between the fourth solenoid valve 65d and the first control valve 56A, and the pilot valve 55D and the first. It regulates hydraulic oil with the control valve 56A and has a second position for communicating the fourth solenoid valve 65d and the first control valve 56A. That is, when the pressure of the hydraulic oil acting from the pilot valve 55D to the fourth shuttle valve 88 is larger than the pressure of the hydraulic oil acting from the fourth solenoid valve 65d to the fourth shuttle valve 88, it is set by the pilot valve 55D. The pressure of the hydraulic oil acts on the second pressure receiving portion 75b. In such a case, the hydraulic oil acting on the fourth solenoid valve 65d to the fourth shuttle valve 88 does not apply pressure to the second pressure receiving portion 75b. On the other hand, when the pressure of the hydraulic oil acting on the 4th shuttle valve 88 from the 4th solenoid valve 65d is larger than the pressure of the hydraulic oil acting on the 4th shuttle valve 88 from the pilot valve 55D, the 4th solenoid valve 65d is used. The set hydraulic oil pressure acts on the second pressure receiving portion 75b. In such a case, the hydraulic oil acting on the fourth shuttle valve 88 from the pilot valve 55D does not apply pressure to the second pressure receiving portion 75b.

Between the outlet side of the third shuttle valve 87 and the first pressure receiving portion 75a in the first working oil passage 46a, and between the outlet side of the fourth shuttle valve 88 and the second pressure receiving portion 75b in the second working oil passage 46b. And, respectively, are provided with a bypass check valve 96. The bypass check valve 96 allows the flow of hydraulic oil from the pilot valve to the first control valve and blocks the flow of hydraulic oil from the first control valve to the pilot valve. Bypass oil passages 95 are provided on the inlet and outlet sides of the bypass check valve 96, and throttles 97 are provided in the bypass oil passages 95.

The changing unit 51 has an input device 93. The input device 93 is connected to the control device 90. The input device 93 includes a plurality of slide switches 93a and 93b. Specifically, the input device 93 is an operating device capable of changing the supply amount of hydraulic oil to the first control valve 56A and the second control valve 56B, that is, the supply amount of hydraulic oil output from the solenoid valve 65. be. In other words, the input device 93 is an operating device that sets the opening degree of the solenoid valve 65 connected to the control valves 56A and 56B. The slide switches 93a and 93b are variable resistors that can detect the amount of movement (operation amount), such as a slide volume. The operation signals of the slide switches 93a and 93b are input to the control device 90. For example, when the slide switch 93a is slid in one direction, the control device 90 controls to open the first solenoid valve 65a associated with the slide switch 93a. When the slide switch 93a is slid in the other direction, the control device 90 controls to open the second solenoid valve 65b. That is, when the slide switch 93a is operated, the bucket 11 can be operated via the second control valve 56B and the bucket cylinder 15. Further, when the slide switch 93b is slid in one direction, the control device 90 controls to open the third solenoid valve 65c associated with the slide switch 93b. When the slide switch 93b is slid in the other direction, the control device 90 controls to open the fourth solenoid valve 65d. That is, when the slide switch 93b is operated, the boom 10 can be operated via the first control valve 56A and the boom cylinder 14. The input device 93 is not limited to the slide switches 93a and 93b, and may be any device as long as it inputs a signal to the control device 90. For example, when the operating device is a push switch, the solenoid valve 65 to be operated may be opened to a predetermined size when the push switch is pressed. Further, the operation target of the slide switches 93a and 93b is not limited to the boom 10 or the bucket 11, and any hydraulic device provided in the work machine 1 may be used. As a result, the operator operates the first operating member 54 and the second operating member 58 to operate the hydraulic system via the pilot valves 55C, 55D, 59C, 59D and the plurality of slide switches 93a, 93b to operate the control device. The boom cylinder 14 and the bucket cylinder 15 can be operated by two systems, the 90 and the electric system via the solenoid valve 65. That is, the hydraulic system of the work machine 1 is provided with a hydraulic system having excellent operability and durability, and also has two operating systems, an electric system capable of fine operation and excellent versatility. Be prepared. The flood control system for the work system in the second embodiment may be applied to the flood control system for the traveling system.

The hydraulic system of the work machine 1 described above includes an input device 93, and the control device 90 controls the solenoid valve 65 in response to the operation of the input device 93. As a result, the operator can operate the first hydraulic device 56B by operating the input device 93. Therefore, the first hydraulic system consists of two systems, one is a hydraulic system that operates the operating member 58 via the operating valves 59C and 59D, and the other is an electric system that operates the input device 93 via the control device 90 and the solenoid valve 65. The device 56B can be operated. That is, the hydraulic system of the work machine 1 is provided with a hydraulic system having excellent durability and operability, and also has two operating systems, an electric system capable of fine operation and excellent versatility. Be prepared.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and it is intended that all modifications within the meaning and scope equivalent to the scope of claims are included.

1 Working machine 14 Boom cylinder 15 Bucket cylinder 45 Running oil passage 46 Working oil passage 51 Change part 54 First operating member 55 Pilot valve 56A First control valve (boom control valve)
56B 2nd control valve (bucket control valve)
58 2nd operation member 59 Pilot valve 64 Branch oil passage 65 Solenoid valve 66 Confluence 71 1st check valve 72 2nd check valve 85 1st shuttle valve 86 2nd shuttle valve 87 3rd shuttle valve 88 4th shuttle valve 93 Input device P1 1st hydraulic pump

Claims (5)

A hydraulic pump that discharges hydraulic oil and
The first flood control device that can be operated by hydraulic oil,
The operating members operated by the operator and
An input device that is different from the operating member and is operated by the operator.
An operating valve having a rod that moves according to the operation of the operating member, and the pressure of the hydraulic oil can be changed according to the movement of the rod.
A solenoid valve that can change the pressure of hydraulic oil according to the operation of the input device,
When the operator operates one of the operating member and the input device to operate either the operating valve or the solenoid valve, the hydraulic oil is supplied from the one to the first hydraulic device, and the hydraulic oil is supplied from the one. When the operator operates both the operating member and the input device to operate both the operating valve and the solenoid valve in the first state of operating the first hydraulic device, the operating member and the input Of the hydraulic oil supplied by the device, the hydraulic oil having the higher pressure is supplied to the first flood control device, and the change part that can be changed to the second state in which the first hydraulic device is operated, and
The hydraulic system of the working machine equipped with. A supply oil passage connecting the operation valve and the first flood control device,
The hydraulic system for a working machine according to claim 1, further comprising a branch oil passage connected to the solenoid valve and merging with the supply oil passage. The change portion is provided at the confluence of the supply oil passage and the branch oil passage, and communicates the operation valve with the first hydraulic equipment, and hydraulic oil between the solenoid valve and the first hydraulic equipment. A shuttle valve that can be switched between a first position that regulates the operation valve and a second position that regulates the hydraulic oil between the operation valve and the first hydraulic device and communicates the solenoid valve and the first hydraulic device is provided. The hydraulic system for the work machine according to claim 2. It is provided in the supply oil passage and allows the flow of hydraulic oil from the operation valve to the first hydraulic equipment, and regulates the flow of hydraulic oil from the first hydraulic equipment and the solenoid valve to the operation valve. The first check valve and
It is provided in the branch oil passage and allows the flow of hydraulic oil from the solenoid valve to the first hydraulic device, and regulates the flow of hydraulic oil from the first hydraulic device and the operation valve to the solenoid valve. The second check valve and
2. The hydraulic system for a working machine according to claim 2. It is arranged between the confluence of the supply oil passage and the branch oil passage and the first hydraulic equipment, and allows the flow of hydraulic oil from the confluence of the supply oil passage to the first hydraulic equipment. A bypass check valve that blocks the flow of hydraulic oil from the first flood control device to the confluence of the supply oil passages,
In the supply oil passage, a bypass oil passage connected to the inlet side and the outlet side of the bypass check valve and provided with a throttle, and a bypass oil passage.
The hydraulic system for a working machine according to any one of claims 2 to 4.

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