JP2019065997A - Hydraulic system of work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic system for a working machine having excellent operability and versatility. A hydraulic system of a working machine moves according to a hydraulic pump P1 for discharging hydraulic oil, a first hydraulic device 56B that can be operated by the hydraulic oil, an operable operating member 58, and an operation of the operating member. One of an operation valve 59 having a rod to be operated and the pressure of the hydraulic oil can be changed according to the movement of the rod, a solenoid valve 65 capable of changing the pressure of the hydraulic oil, and an operation valve and a solenoid valve. It is provided with a change part that can be changed to a first state in which one is operated and a second state in which both the operation valve and the solenoid valve are operated. Further, the changing unit has a control device 90 for controlling the solenoid valve and an input device for inputting a signal to the control device, and the control device controls the solenoid valve according to the operation of the input device. [Selection diagram] Fig. 2

Description

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

Conventionally, a working machine is operated by an operating system of either a hydraulic system or an electrical system. For example, the work machine disclosed in Patent Document 1 can be operated by an operating member, an operating valve whose pressure can be changed according to the operation of the operating member, and hydraulic oil output from the operating valve. And hydraulic equipment.
Further, the work machine disclosed in Patent Document 2 includes a control device that outputs a control signal based on an operation amount of a swingable first switch, and a solenoid valve that controls a pilot pressure based on the control signal. And a control valve for supplying hydraulic fluid to the actuator based on the pilot pressure.

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

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

  The present invention has been made to solve the problems of the prior art as described above, and it is an object of the present invention to provide a hydraulic system of a working machine excellent in operability and versatility.

The technical means of the present invention for solving this technical problem are as follows.
The hydraulic system of the working machine has a hydraulic pump for discharging hydraulic fluid, a first hydraulic device operable by the hydraulic fluid, an operating member operable, and a rod moving according to the operation of the operating member. And operating an operating valve whose pressure can be changed according to the movement of the rod, a solenoid valve capable of changing the pressure of the hydraulic oil, and one of the operating valve and the solenoid valve The change unit is changeable into one state and a second state in which both the operation valve and the solenoid valve are operated.

The change unit includes a control device that controls the solenoid valve, and an input device that inputs a signal to the control device, and the control device controls the solenoid valve in accordance with an operation of the input device.
The hydraulic system of the working machine is operable by hydraulic fluid and includes a second hydraulic device different from the first hydraulic device, and the change unit includes a control device that controls the solenoid valve, the control The device controls the solenoid valve in response to the operation of the second hydraulic device.

The hydraulic system of the working machine includes an oil supply passage connecting the operation valve and the first hydraulic device, and a branch oil passage connected to the solenoid valve and joining the oil supply passage.
The change unit is provided at a junction of the supply oil passage and the branch oil passage, and communicates the operation valve with the first hydraulic device, and the hydraulic oil of the solenoid valve and the first hydraulic device And a shuttle valve capable of switching between the solenoid valve and the second hydraulic device for communicating the hydraulic oil between the operation valve and the first hydraulic device. ing.

  The hydraulic system of the working machine is provided in the supply oil passage, and allows the flow of hydraulic oil from the operation valve toward the first hydraulic device, and from the first hydraulic device and the solenoid valve to the operation valve A first check valve for restricting the flow of hydraulic oil, and a hydraulic oil provided in the branch oil passage and permitting the flow of hydraulic oil from the solenoid valve to the first hydraulic device; And a second check valve for restricting the flow of hydraulic oil from the operation valve toward the solenoid valve.

  The first hydraulic device is a bucket control valve capable of operating a bucket cylinder, and the second hydraulic device is a boom control valve capable of operating a boom cylinder.

  According to the present invention, it is possible to provide a hydraulic system of a working machine excellent in 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 working system in 1st Embodiment. It is the schematic of the 1st modification of the hydraulic system of the working system in 1st Embodiment. It is the schematic of the 2nd modification of the hydraulic system of the working system in 1st Embodiment. It is the schematic of the hydraulic system of the working system in 2nd Embodiment. It is a side view showing a track loader which is an example of a work machine. It is a side view showing a part of truck loader in the state where the cabin was raised.

Hereinafter, a suitable embodiment of a hydraulic system of work machine 1 concerning the present invention is described, referring to drawings suitably.
First Embodiment
Hereinafter, embodiments of the present invention will be described based on the drawings.
FIG. 6 shows a side view of a working machine according to the present invention. In FIG. 6, a compact track loader is shown as an example of the work machine. However, the working machine according to the present invention is not limited to the compact track loader, and may be, for example, another type of loader working machine such as a skid steer loader. In addition, a working machine other than the loader working machine may be used.

  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 of the driver sitting on the driver's seat 8 of the work machine 1 (left side in FIG. 6) is forward, the rear side of the driver (right side in FIG. 6 is described as the left, and the right side of the driver (the far side in FIG. 6) is the right. Moreover, the horizontal direction which is a direction orthogonal to the front-back direction is demonstrated as a body width direction. The direction from the central part of the airframe 2 to the right or left will be described as the direction outside the airframe. In other words, the extracorporeal direction is the width direction of the vehicle and is the direction away from the vehicle 2. The direction opposite to the direction outside the aircraft will be described as the direction inside the aircraft. In other words, the inside of the vehicle is the width direction of the vehicle and is the direction approaching the vehicle 2.

The cabin 3 is mounted on the airframe 2. The cabin 3 is provided with a driver's seat 8. The work device 4 is mounted on the machine body 2. The traveling device 5 is provided on the outside of the airframe 2. At the rear of the fuselage 2, a motor 32 is mounted.
The work device 4 includes a boom 10, a work implement 11, a lift link 12, a control link 13, a boom cylinder 14, and a bucket cylinder 15.

  The boom 10 is vertically swingably provided on the right and left sides of the cabin 3. 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 pivotable. The lift link 12 and the control link 13 support the base (rear portion) of the boom 10 so that the boom 10 can swing up and down. The boom cylinder 14 raises and lowers the boom 10 by expanding and contracting. The bucket cylinder 15 swings the bucket 11 by expanding and contracting.

The fronts of the left and right booms 10 are connected to each other by an odd-shaped connecting pipe. The base parts (rear parts) of the booms 10 are connected by a circular connection pipe.
The lift link 12, the control link 13 and the boom cylinder 14 are respectively provided on the left and right sides of the machine body 2 corresponding to the booms 10 on the left and right sides.
The lift links 12 are provided longitudinally at the rear of the base of each boom 10. An upper portion (one end side) of the lift link 12 is rotatably supported about a lateral axis via a pivot (first pivot) 16 near the rear of the base of each boom 10. In addition, the lower part (the other end side) of the lift link 12 is rotatably supported about a lateral axis via a pivot (a second pivot) 17 near the rear of the vehicle body 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 about a lateral axis via a pivot shaft (third pivot shaft) 18. The third pivot shaft 18 is provided at the base of each boom 10 and at the front of the base. The lower portion of the boom cylinder 14 is rotatably supported about a lateral axis via a pivot shaft (fourth pivot shaft) 19. The fourth pivot shaft 19 is provided near the lower portion of the rear 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 about a lateral axis via a pivot shaft (fifth pivot shaft) 20. The fifth pivot shaft 20 is provided at a position corresponding to the front of the lift link 12 in the airframe 2. The other end of the control link 13 is rotatably supported about a lateral axis via a pivot shaft (sixth pivot shaft) 21. The sixth pivot shaft 21 is the boom 10 and is provided in front of the second pivot shaft 17 and above the second pivot shaft 17.

  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 by expanding and contracting the boom cylinder 14, and the tip of each boom 10 Rises and falls. The control link 13 swings up and down around the fifth pivot 20 as the booms 10 move 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.

Instead of the bucket 11, another work tool can be attached to the front of the boom 10. Other working tools are, for example, attachments such as hydraulic crushers, hydraulic breakers, angle blooms, earth augers, pallet forks, sweepers, mowers, snow blowers, and the like (preliminary attachments).
A connecting member 50 is provided at the front of the left boom 10. The connection member 50 is a device that connects the hydraulic device equipped to the spare attachment and the first pipe member such as a pipe provided to the boom 10. Specifically, the first pipe can be connected to one end of the connection member 50, and the second pipe connected to the hydraulic device of the backup attachment can be connected to the other end. Thus, the hydraulic oil flowing through the first pipe passes through the second pipe and is supplied to the hydraulic device.

The bucket cylinders 15 are respectively disposed near the front of each boom 10. By expanding and contracting the bucket cylinder 15, the bucket 11 is swung.
In the present embodiment, crawler type (including semi crawler type) traveling devices are adopted for the left and right traveling devices 5. In addition, you may employ | adopt the travel apparatus of the wheel type which has a front wheel and a rear wheel.

Next, the hydraulic system of the traveling 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, and a motor 32; And a traveling drive unit 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 constituted by a fixed displacement gear pump. The first hydraulic pump P1 discharges hydraulic oil mainly used for control. For convenience of explanation, the tank 22 storing 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 a pilot oil, and the pressure of the pilot oil may be referred to as a pilot pressure. On the discharge side of the first hydraulic pump P1, an oil passage (discharge oil passage) 40 in which hydraulic oil (pilot oil) flows is provided. In the discharge oil passage (first oil passage) 40, a first travel motor device 31L and a second travel motor device 31R are provided.

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 motor 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 drives the first travel motor device 31L and the second travel motor device 31R, and includes a drive circuit (left drive circuit) 34L for driving the first travel motor device 31L, and a second travel And a drive circuit (right drive circuit) 34R for driving the motor device 31R.

  The left drive circuit 34L and the right drive circuit 34R respectively include traveling pumps (traveling hydraulic pumps) 53L, 53R, shifting oil passages 57h, 57i, and a second charge oil passage 57j. The shifting oil passages 57h and 57i are oil passages connecting the traveling pumps 53L and 53R and the traveling motor 36. The second charge oil passage 57j 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, 53R are traveling actuators that can be operated by hydraulic oil. The traveling pumps 53L and 53R have a forward pressure receiving portion 53a and a reverse pressure receiving portion 53b on which a pilot pressure acts. The pilot pressure applied to the forward pressure receiving portion 53a and the reverse pressure receiving portion 53b changes the angle of the swash plate. By changing the angle of the oblique plate, it is possible to change the output (discharge amount of hydraulic fluid) of the traveling pumps 53L, 53R and the discharge direction of hydraulic fluid.

The first travel motor device 31L is a motor for transmitting power to the drive shaft of the travel device 5 provided on the left side of the machine body 2. The second travel motor device 31R is a motor for transmitting power to the drive shaft of the travel device 5 provided on the right side of the vehicle body 2.
The first travel motor device 31L has a travel motor 36, a longitudinal switching valve 35, and a travel control valve (hydraulic switching 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) at the time of operation.
Next, the hydraulic system of the working system will be described.
As shown in FIG. 2, the hydraulic system includes a plurality of control valves 56 and a working 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 configured by a fixed displacement 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 a 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) hydraulic devices such as, for example, a boom, a bucket, a hydraulic crusher, a hydraulic breaker, an angle bloom, an earth auger, a pallet fork, a sweeper, a mower, 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 a hydraulic cylinder (boom cylinder) 14 that controls a boom. The second control valve 56B is a valve that controls a hydraulic cylinder (bucket cylinder) 15 that controls a bucket. The third control valve 56C is a valve for controlling a hydraulic device (hydraulic cylinder, hydraulic motor) mounted on a preliminary attachment such as a hydraulic crusher, hydraulic breaker, angle bloom, earth auger, pallet fork, sweeper, mower, snow blower etc. is there. In the following description, the first control valve 56A may be referred to as a boom control valve. Also, the second control valve 56B may be referred to as a bucket control valve.

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

  An oil supply and discharge passage 83 is connected to the third control valve 56C. One end of the oil supply and discharge passage 83 is connected to the oil supply and discharge port of the third control valve 56C, the middle part of the oil supply and discharge passage 83 is connected to the connecting member 50, and the other end of the oil supply and discharge passage 83 is Connected to the hydraulic equipment of the backup attachment. Specifically, the oil supply and discharge passage 83 includes a first oil supply and discharge passage 83a connecting the first supply and discharge port of the third control valve 56C and the first port of the connection member 50. In addition, the oil supply and discharge passage 83 includes a second oil supply and discharge passage 83b that connects the second supply and discharge port of the third control valve 56C and the second port of the connection member 50. That is, by operating the third control valve 56C, hydraulic fluid flows from the third control valve 56C toward the first supply / discharge oil passage 83a, or from the third control valve 56C toward the second supply / discharge oil passage 83b. Hydraulic fluid can flow.

  As shown in FIGS. 1 and 2, the operation (traveling operation) related to traveling of the work machine 1 and the operation (work operation) related to work are performed by the first operating device 47 provided on the left of the driver's seat 8 and And the second operating device 48 provided on the right of the In other words, the first operating device 47 and the second operating device 48 are hydraulic devices for the traveling system (the traveling motor 36, the traveling pumps 53L, 53R), and hydraulic devices for the working system (the first control valve 56A, the second control valve 56B). , The third control valve 56C, the boom cylinder 14, the bucket cylinder 15, the hydraulic cylinder provided in the spare attachment, and the 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 traveling operation and work operation, and has a first operating member 54. The first operation member 54 is a lever capable of performing a first operation to move back and forth and a second operation to move left and right (in the machine width direction) different from the front and back. In other words, the first operation member 54 is a lever that can be moved in one direction (e.g., front, left) and in another direction (e.g., 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 operation member 54 doubles as an operation member for traveling (travel operation member) and an operation member for operation (work operation 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 at the lower part of the first operation member 54. The plurality of pilot valves 55 can change the pressure of the hydraulic fluid in accordance with the operation of the first operation member 54. Specifically, the pilot valve 55 has a rod that abuts on the first operation member 54. That is, in accordance with the operation of the first operation member 54, the pressure of the hydraulic fluid output from the pilot valve 55 is changed by pushing the rod. 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 operated by the front operation in the first operation (front and rear operation), and the pressure of the hydraulic fluid to be output changes according to the operation amount (operation) of the front operation. The pilot valve 55B is a valve operated by the rear operation in the first operation (front and rear operation), and the pressure of the hydraulic fluid 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 operated by the first operation, and perform movements corresponding to the traveling operation.

  The pilot valve 55C is a valve operated by the left operation in the second operation (right and left operation), and the pressure of the hydraulic fluid to be output changes according to the operation amount (operation) of the left operation. The pilot valve 55D is a valve operated by the right operation in the second operation (right and left operation), and the pressure of the hydraulic fluid 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 operated by the second operation, and perform movements corresponding to the work operation.

  The second operating device 48 is a device capable of performing both traveling operation and work operation, and has a second operating member 58. The second operation member 58 is a lever capable of performing a first operation to move back and forth and a second operation to move left and right (in the machine width direction) different from the front and back. In other words, the second operating member 58 is a lever that can be moved in one direction (eg, front, left) and in another direction (eg, back, 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 operation member 58 doubles as a traveling operation member (traveling operation member) and an operation member (work operation member). The second operation 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 operation member 58. The plurality of pilot valves 59 can change the pressure of the hydraulic fluid in accordance with the operation of the second operation member 58. Specifically, the pilot valve 59 has a rod that abuts on the second operating member 58. That is, in accordance with the operation of the second operation member 58, the pressure of the hydraulic fluid output from the pilot valve 59 is changed by pushing the rod. 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 operated by the front operation in the second operation (front and rear operation), and the pressure of the hydraulic fluid to be output changes according to the operation amount (operation) of the front operation. The pilot valve 59B is a valve operated by the rear operation in the first operation (front and rear operation), 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 operated by the first operation, and perform movements corresponding to the traveling operation.

  The pilot valve 59C is a valve operated by the left operation in the first operation (right and left operation), and the pressure of the hydraulic fluid to be output changes according to the operation amount (operation) of the left operation. The pilot valve 59D is a valve operated by the right operation in the second operation (right and left operation), and the pressure of the hydraulic fluid 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 operated by the second operation, and perform movements corresponding 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 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, the front) of the first operation member 54 is referred to as "first pilot valve", and the other direction (for example, the rear) of the first operation member 54 The pilot valve 55B actuated by the first control valve is referred to as a "second pilot valve", and the pilot valve 59A actuated according to one direction (for example, the front) of the second operation member 58 is referred to as a "third pilot valve". The pilot valve 59B that operates in the other direction (for example, after) of the two operation members 58 is referred to as a "fourth pilot valve".

Next, the relationship between the traveling pilot valve, the operation pilot valve, and the hydraulic device will be described. The symbols “W1”, “W2”, “D1” and “D2” shown in FIG. 1 and FIG. 2 indicate connection destinations of the oil passage.
The traveling pilot valve and the traveling pumps 53L and 53R, which are one of traveling hydraulic devices (traveling hydraulic devices), are connected by a traveling oil passage 45. The traveling oil passage 45 includes 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 backward 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 backward pressure receiving portion 53b of the traveling pump 53R.

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

  When the first operation member 54 is tilted rearward, the second pilot valve 55B is operated to output a pilot pressure from the second pilot valve 55B. The pilot pressure acts on the reverse pressure receiving portion 53b of the traveling pump 53L. When the second operation member 58 is tilted rearward, the fourth pilot valve 59B is operated to output a pilot pressure from the fourth pilot valve 59B. The pilot pressure acts on the reverse pressure receiving portion 53b of the traveling pump 53R.

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

When one of the first operating member 54 and the second operating member 58 is swung forward and the other is swung backward, the left traveling motor 36 and the right traveling motor 36 move in different directions. As a result, the work implement 1 pivots to the right or left.
As described above, by moving the first operation member 54 back and forth or moving the second operation member 58 back and forth, it is possible to perform a traveling operation to move the work implement 1 forward, reverse, right turn, and left turn.

  Further, the work pilot valve and the control valve 56 which is one of the hydraulic equipment (work hydraulic equipment) of the work system are connected by the work oil passage 46. The working oil passage 46 includes 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 connecting 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 connecting 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 connecting 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 connecting the pilot valve 59D and the pressure receiving portion of the second control valve 56B.

  When the first operation member 54 is tilted to the left, the pilot valve 55C is operated to set the pilot pressure of the pilot oil output from the pilot valve 55C. The pilot pressure acts on the pressure receiving portion of the first control valve 56A, the boom cylinder 14 is extended, and the boom 10 is raised. When the first operation 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. The 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 operation member 58 is tilted to the left, the pilot valve 59C is operated to set the pilot pressure of the pilot oil output from the pilot valve 59C. The 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 to set the pilot pressure of the pilot oil output from the pilot valve 59D. The pilot pressure acts on the pressure receiving portion of the second control valve 56B, and the bucket cylinder 15 extends, and the bucket 11 performs a dumping operation.

Therefore, by moving the first operation member 54 to the left and right or moving the second operation member 58 to the left and right, work operations such as raising and lowering of the boom 10, dumping operation of the bucket or squee operation can be performed.
The hydraulic system includes a hydraulic pump, a first hydraulic device, a second hydraulic device, an operation member, and an operation valve. In the present embodiment, the hydraulic pump is a first hydraulic pump P1. The first hydraulic device is a second control valve 56B. The second hydraulic device is a first control valve 56A. The operating member is a second operating member 58. The control valves are pilot valves 59C and 59D. The hydraulic system also includes an oil supply passage. In the present embodiment, the supply oil passage is a third working oil passage 46c connecting the pilot valve 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 second control valve 56B has a first pressure receiving portion 76a and a second pressure receiving portion 76b, and can be operated by a pressure difference between hydraulic oil acting on the first pressure receiving portion 76a and the second pressure receiving portion 76b. . Specifically, a third working oil passage 46c is connected to the first pressure receiving portion 76a. A fourth working oil passage 46d is connected to the first pressure receiving portion 76b. That is, the second control valve 56B has a neutral position, a first position different from the neutral position, a neutral position, and a first position depending on the pressure difference between the pilot pressures of the hydraulic fluid acting on the first pressure receiving portion 76a and the second pressure receiving portion 76b. Switch to a second position 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 joining the third working oil passage 46c and a second branch oil passage 64b joining the fourth working oil passage 46d.
The solenoid valve 65 is a solenoid 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 therethrough. 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 at the inlet side to the first hydraulic pump P 1 and connected at the outlet side to the branch oil passage 64. Describing in detail, the first electromagnetic valve 65a is connected at the outlet side to the first branch oil passage 64a. 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 paths 46c and 46d are connected to the first hydraulic pump P1. That is, hydraulic oil can be applied from the hydraulic pump P1 to the second control valve 56B via the solenoid valve 65. Specifically, the hydraulic oil discharged by the first hydraulic pump P1 can be joined to the working oil passages 46c and 46d via the solenoid valve 65 and the branch oil passage 64, respectively. Thus, the hydraulic oil discharged by the hydraulic pump P1 can be applied to the second control valve 56B.

  The hydraulic system includes a change unit 51. The changing unit 51 can change between a first state in which one of the pilot valves 59C and 59D and the solenoid valve 65 is operated, and a second state in which both the pilot valves 59C and 59D and the solenoid valve 65 are operated. is there. The change unit 51 includes shuttle valves 85 and 86. The shuttle valve 85 is provided at a joining portion 66 of the working oil passage 46 and the branch oil passage 64. The shuttle valve 86 is provided at a second junction 66b where the fourth working oil passage 46d and the second branch oil passage 64b merge.

When either the pilot valve 59C or the solenoid valve 65 is actuated (in the first state), the shuttle valve 85 sets the pressure of the hydraulic fluid set by the actuated pilot valve 59C or the solenoid valve 65 to the first pressure. The pressure is transmitted to the pressure receiving portion 76a.
When either the pilot valve 59D or the solenoid valve 65 is actuated (in the first state), the shuttle valve 86 is set to the pressure of the hydraulic fluid set by the actuated pilot valve 59D or the solenoid valve 65 The pressure is transmitted to the pressure receiving portion 76b.

Also, when both the pilot valve 59C and the solenoid valve 65 are actuated (in the second state), the shuttle valve 85 sets the pressure of the hydraulic fluid higher than that of the actuated pilot valve 59C or the solenoid valve 65, It transmits to the 1st pressure receiving part 76a.
When both of the pilot valve 59D and the solenoid valve 65 are actuated (in the second state), the shuttle valve 85 sets the pressure of the hydraulic fluid higher than that of the actuated pilot valve 59D or the solenoid valve 65 to the second The pressure is transmitted to the pressure receiving portion 76b.

  Therefore, when in the first state, the changing unit 51 sets the pressure of the hydraulic oil set by the operation valves 59C and 59D or the pressure of the hydraulic oil set by the solenoid valve 65 (1) It can be applied to a hydraulic device to operate the first hydraulic device. On the other hand, when in the second state, the changing unit 51 controls either the pressure of the hydraulic oil set by the operation valves 59C and 59D or the pressure of the hydraulic oil set by the solenoid valve 65 to the control valve 56 or the like. The first hydraulic device can be operated by applying to the first hydraulic device.

  The change unit 51 also includes a control device 90. The controller 90 controls the solenoid valve 65. The control device 90 is composed of a CPU and the like, and performs various processes related to devices connected to the control device 90. The controller 90 is connected to an angle detector 91 for detecting the angle of the boom 10. The controller 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 without the operator operating the second operation member 58. Switching to the horizontal control mode is performed by a switch 92 connected to the controller 90. The switch 92 is a member for instructing the control device 90 to switch to the horizontal control mode. When the switch 92 is pressed, a signal is output to the controller 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 that outputs a signal to the control device 90.

  When the horizontal control mode is released, hydraulic fluid is applied from the pilot valves 59C and 59D to the second control valve 56B. Also, the controller 90 closes the solenoid valve 65. On the other hand, when shifting to the horizontal control mode, the control device 90 controls the solenoid valve 65 to cause hydraulic oil to act on the second control valve 56B from the solenoid valve 65. In other words, any one of the hydraulic oil of the pilot valves 59C and 59D and the hydraulic oil of the solenoid valve 65 is applied to the second control valve 56B which is the first hydraulic device.

  In the horizontal control mode, the controller 90 operates the bucket 11 in accordance with the boom angle detected by the angle detector 91. In other words, the control device 90 controls the solenoid valve 65 in accordance with 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 movement angle of the boom 10 from the time of transition to the horizontal control mode. Specifically, when the boom cylinder 14 is contracted and the boom 10 is lowered, the control device 90 controls the solenoid valve 65 so that the bucket 11 performs the squeeze operation by the same movement angle of the boom 10. On the other hand, when the boom cylinder 14 extends and the boom 10 ascends, the control device 90 controls the solenoid valve 65 so that the bucket 11 dumps by the same value as the movement angle of the boom 10. That is, the bucket 11 is horizontally controlled. That is, the controller 90 controls the solenoid valve 65 in accordance with the operation of the first control valve 56A. Thus, the movement angle of the bucket 11 connected to the second control valve 56B can be controlled according to the movement angle of the boom 10 connected to the first control valve 56A via the boom cylinder 14. For this reason, since the above-mentioned configuration is simple and removable, the horizontal control function of the bucket 11 can be introduced into the hydraulic system of the working machine 1. Note that the bucket 11 may be operated according to the movement angle of the boom 10, and a detection device that measures the extension and 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 operation 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 a first joining portion 66a where the third working oil passage 46c and the first branch oil passage 64a join together. The first shuttle valve 85 communicates the pilot valve 59C with the second control valve 56B, and controls the hydraulic oil of the first solenoid valve 65a and the second control valve 56B, and the pilot valve 59C with the second position. The hydraulic oil with the control valve 56B is regulated, and a second position connecting the first solenoid valve 65a and the second control valve 56B is provided. That is, when the pressure of the hydraulic fluid acting on the first shuttle valve 85 from the pilot valve 59C is larger than the pressure of the hydraulic fluid acting on the first shuttle valve 85 from the first solenoid valve 65a, the pilot valve 59C is set. 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 shuttle valve 85 from the first solenoid valve 65a does not exert pressure on the first pressure receiving portion 76a. On the other hand, when the pressure of the hydraulic fluid acting on the first shuttle valve 85 from the first solenoid valve 65a is larger than the pressure of the hydraulic fluid acting on the first shuttle valve 85 from the pilot valve 59C, the first solenoid valve 65a The pressure of the set hydraulic oil 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 exert pressure on the first pressure receiving portion 76a.

  The second shuttle valve 86 is provided at a second joining portion 66b where the fourth working oil passage 46d and the second branch oil passage 64b join together. The second shuttle valve 86 establishes communication between the pilot valve 59D and the second control valve 56B, and regulates the hydraulic oil of the second solenoid valve 65b and the second control valve 56B, and the pilot valve 59D and the second position. The hydraulic fluid with the control valve 56B is regulated, and the second position is established to communicate the second solenoid valve 65b with the second control valve 56B. That is, when the pressure of the hydraulic fluid acting from the pilot valve 59D to the second shuttle valve 86 is larger than the pressure of the hydraulic fluid acting from the second solenoid valve 65b to the second shuttle valve 86, the pilot valve 59D is set. The pressure of the hydraulic fluid acts on the second pressure receiving portion 76b. In such a case, the hydraulic oil acting from the second solenoid valve 65b to the second shuttle valve 86 does not exert pressure on the second pressure receiving portion 76b. On the other hand, when the pressure of the hydraulic fluid acting on the second shuttle valve 86 from the second solenoid valve 65 b is larger than the pressure of the hydraulic fluid acting on the second shuttle valve 86 from the pilot valve 59 D, the second solenoid valve 65 b The pressure of the set hydraulic oil acts on the second pressure receiving portion 76b. In such a case, the hydraulic oil acting from the pilot valve 59D to the second shuttle valve 86 does not exert pressure on the second pressure receiving portion 76b. As a result, with the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64, the hydraulic oil having the higher pressure can be applied to the second control valve 56B. On the other hand, the action of the lower pressure hydraulic oil on the second control valve 56B can be prevented by the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64. Therefore, any one of the pilot valves 59C and 59D and the solenoid valve 65 can be applied to the second control valve 56B.

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

  FIG. 3 shows a first modification of the first embodiment. The working 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 joining portion 66 of 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 to the merging portion 66, and the flow of hydraulic oil from the merging portion 66 to the pilot valves 59C and 59D. regulate.

On the other hand, the second check valve 72 is provided in each of 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. There is. The second check valve 72 allows the flow of hydraulic oil from the solenoid valve 65 to the merging portion 66 and regulates the flow of hydraulic oil from the merging portion 66 to the solenoid valve 65. Thus, the hydraulic fluid flowing from the pilot valve 59C, 59D to the second control valve 56B is allowed, and the hydraulic fluid flowing from the second control valve 56B and the solenoid valve 65 to the pilot valve 59C, 59D is It can be blocked. Also, allow hydraulic fluid flowing from the solenoid valve 65 to the second control valve 56B, and block hydraulic fluid flowing from the second control valve 56B and the pilot valves 59C and 59D toward the solenoid valve 65. Can. Therefore, it is possible to prevent the backflow of the hydraulic oil from the second control valve 56B and the solenoid valve 65 side to the pilot valves 59C and 59D. In addition, it is possible to prevent the backflow of the hydraulic oil from the second control valve 56B and the pilot valves 59C, 59D to the solenoid valve 65. In the modification described above, the second control valve 56B may be operated only by the operation of the second operation member 58, or the second control valve 56B may be operated only by the control of the control device 90. In addition, the second control valve 56B may be operated by the operation of both the second operation member 58 and the controller 90.

  FIG. 4 shows a second modification of the first embodiment. The first solenoid valve 65a is connected at the inlet side to the second working oil passage 46b and at the outlet side to the branch oil passage 64a. That is, in the horizontal control mode, when the control device 90 opens the first electromagnetic valve 65a from the closing state, the hydraulic oil output from the pilot valve 55D passes through the second working oil passage 46b and the first electromagnetic valve 65a. It flows into the branched oil passage 64a. In such a case, the operation 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 to contract the boom cylinder 14 10 descends. Further, the hydraulic oil output from 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 can control the squeeze operation of the bucket 11 according to the descent of the boom 10 by controlling the opening degree of the first electromagnetic valve 65a. That is, horizontal control of the bucket 11 is possible.

  The hydraulic system of the work machine 1 described above includes the hydraulic pump P1, the first hydraulic device 56B, the operation member 58, the operation valves 59C and 59D, the solenoid valve 65, the control device 90, and the change unit 51. Have. As a result, hydraulic oil can be applied to the first hydraulic device 56B from two different systems of the operation valves 59C and 59D and the solenoid valve 65. For this reason, separately from the operation of the operation member 58 by the operator, the control device 90 opens the solenoid valve 65 and operates the first hydraulic device 56B easily by causing the hydraulic oil to act on the first hydraulic device 56B. Can.

  Further, the hydraulic system of the work machine 1 includes the second hydraulic device 56A, and the control device 90 controls the solenoid valve 65 in accordance with the operation of the second hydraulic device 56A. Thus, the operating angle of the hydraulic device 15 connected to the first hydraulic device 56B can be controlled in accordance with the operating angle of the hydraulic device 14 connected to the second hydraulic device 56A. For this reason, since the above-mentioned configuration is simple and removable, the horizontal control function can be introduced into the hydraulic system of the work implement 1.

  The hydraulic system of the working machine 1 further includes supply oil passages 46 c and 46 d and a branch oil passage 64. As a result, hydraulic oil is supplied to the first hydraulic device 56B from two different oil passages of 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, the control device 90 opens the solenoid valve 65 separately from the operation of the operation member 58 by the operator, and easily causes the first hydraulic device 56B to act on the first hydraulic device 56B via the branch oil passage 64. The hydraulic device 56B can be operated.

  The change unit 51 also includes shuttle valves 85 and 86. As a result, with the hydraulic oil flowing through the supply oil paths 46c and 46d and the hydraulic oil flowing through the branch oil path 64, the hydraulic oil having the higher pressure can be applied to the first hydraulic device 56B. On the other hand, the flow of the lower pressure hydraulic fluid can be blocked by the hydraulic fluid in the supply fluid passages 46c and 46d and the hydraulic fluid in the branch fluid passage 64. Therefore, any one of the operation valves 59C and 59D and the solenoid valve 65 can act on the first hydraulic device 56B.

  The hydraulic system of the work machine 1 also includes a first check valve 71 and a second check valve 72. Thus, the hydraulic fluid flowing from the control valve 59C, 59D to the first hydraulic device 56B is allowed, and the hydraulic fluid flowing from the first hydraulic device 56B and the solenoid valve 65 to the control valve 59C, 59D is It can be blocked. Also, allow hydraulic fluid flowing from the solenoid valve 65 to the first hydraulic device 56B, and block hydraulic fluid flowing from the first hydraulic device 56B and the control valves 59C and 59D toward the solenoid valve 65. Can. Therefore, it is possible to prevent the backflow of the hydraulic oil from the side of the first hydraulic device 56B and the solenoid valve 65 to the operation valves 59C and 59D. In addition, it is possible to prevent the backflow of the hydraulic oil from the side of the first hydraulic device 56B and the operation valves 59C, 59D to the solenoid valve 65.

The first hydraulic device 56B is a bucket control valve 56B, and the second hydraulic device 56A is a boom control valve 56A. Thus, according to the operating angle of the boom 10 connected to the boom control valve 56A via the boom cylinder 14, the operating angle of the bucket 11 connected to the bucket control valve 56B via the bucket cylinder 15 is controlled. Can. For this reason, since the above-mentioned configuration is simple and removable, the horizontal control function can be introduced into the hydraulic system of the work implement 1.
Second Embodiment
FIG. 5 shows a hydraulic system according to a second embodiment of the present invention. The same components as in the first embodiment are given the same reference numerals, and the description thereof is 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 a first hydraulic pump P1. The first hydraulic device is a first control valve 56A and a second control valve 56B. The operating members are the first operating member 54 and the second operating member 58. The control valves are pilot valves 55C, 55D, 59C, 59D. The hydraulic system also includes an oil supply passage. In the present embodiment, the supply oil passage includes 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 a pressure difference between hydraulic oil applied to the first pressure receiving portion 75a and the second pressure receiving portion 75b. is there. Specifically, the first pressure receiving portion 75a is connected to the first working oil passage 46a. The second pressure receiving portion 75b is connected to the second working oil passage 46b. That is, the first control valve 56B has a neutral position, a first position different from the neutral position, a neutral position, and a first position depending on the pressure difference between the pilot pressures of the hydraulic fluid acting on the first pressure receiving portion 75a and the second pressure receiving portion 75b. Switch to a second position different from the position.

The branch oil passage 64 includes a third branch oil passage 64c joining the first working oil passage 46a and a fourth branch oil passage 64d joining 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 third solenoid valve 65c is connected at the outlet side thereof to the third branch oil passage 64c. The fourth solenoid valve 65d is connected at the outlet side thereof 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 paths 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 fluid discharged by the hydraulic pump P1 can act on the working fluid passages 46a and 46b via the solenoid valve 65 and the branch fluid passage 64. Thus, the hydraulic oil discharged by the hydraulic pump P1 can be applied to the first control valve 56A.

  The change unit 51 includes shuttle valves 87 and 88. The shuttle valves 87 and 88 are provided at the joining portion 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, and the solenoid valve 65 and the first valve The first position for regulating the hydraulic oil with the control valve 56A, and the hydraulic oil for the pilot valves 55C, 55D and the first control valve 56A, and the second position for communicating the solenoid valve 65 with the first control valve 56A And. Specifically describing the shuttle valves 87 and 88, 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 at a third junction 66c where the first working fluid passage 46a and the third branch fluid passage 64c merge. The third shuttle valve 87 communicates the pilot valve 55C with the first control valve 56A, and has a first position for restricting the hydraulic oil of the third solenoid valve 65c and the first control valve 56A, the pilot valve 55C and the first position. The hydraulic oil with the control valve 56A is regulated, and there is a second position connecting the third solenoid valve 65c and the first control valve 56A. That is, when the pressure of the hydraulic fluid acting on the third shuttle valve 87 from the pilot valve 55C is larger than the pressure of the hydraulic fluid acting on the third shuttle valve 87 from the third solenoid valve 65c, the pilot valve 55C is set. The pressure of the hydraulic fluid acts on the first pressure receiving portion 75a. In such a case, the hydraulic oil acting from the third solenoid valve 65c to the third shuttle valve 87 does not exert pressure on the first pressure receiving portion 75a. On the other hand, when the pressure of the hydraulic fluid acting from the third solenoid valve 65c to the third shuttle valve 87 is larger than the pressure of the hydraulic fluid acting from the pilot valve 55C to the third shuttle valve 87, the third solenoid valve 65c The pressure of the set hydraulic oil acts on the first pressure receiving portion 75a. In such a case, the hydraulic oil acting from the pilot valve 55C to the third shuttle valve 87 does not exert pressure on the first pressure receiving portion 75a.

  The fourth shuttle valve 88 is provided at a fourth junction 66d where the second working oil passage 46b and the fourth branch oil passage 64c merge. The fourth shuttle valve 88 establishes communication between the pilot valve 55D and the first control valve 56A, and regulates the hydraulic oil of the fourth solenoid valve 65d and the first control valve 56A, and the pilot valve 55D and the first position. The hydraulic oil with the control valve 56A is regulated, and there is a second position in which the fourth solenoid valve 65d and the first control valve 56A communicate with each other. That is, when the pressure of the hydraulic fluid acting from the pilot valve 55D to the fourth shuttle valve 88 is larger than the pressure of the hydraulic fluid acting from the fourth electromagnetic valve 65d to the fourth shuttle valve 88, the pilot valve 55D is set. The pressure of the hydraulic fluid acts on the second pressure receiving portion 75b. In such a case, the hydraulic oil acting from the fourth solenoid valve 65 d to the fourth shuttle valve 88 does not exert pressure on the second pressure receiving portion 75 b. On the other hand, if the pressure of the hydraulic fluid acting on the fourth solenoid valve 65d to the fourth shuttle valve 88 is greater than the pressure of the hydraulic fluid acting on the fourth shuttle valve 88 from the pilot valve 55D, then the fourth solenoid valve 65d The pressure of the set hydraulic oil 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 exert pressure on the second pressure receiving portion 75b.

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

  The change 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 amount of hydraulic fluid supplied to the first control valve 56A and the second control valve 56B, that is, the amount of hydraulic fluid output from the solenoid valve 65. is there. 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 capable of detecting the amount of movement (the amount of operation), for example, like a slide volume. 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 the first electromagnetic valve 65a associated with the slide switch 93a to open. When the slide switch 93a is slid in the other direction, the control device 90 controls the second electromagnetic valve 65b to open. 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. In addition, when the slide switch 93b is slid in one direction, the control device 90 performs control 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 the fourth solenoid valve 65d to open. That is, when the slide switch 93 b is operated, the boom 10 can be operated via the first control valve 56 A and the boom cylinder 14. The input device 93 is not limited to the slide switches 93a and 93b, and may be anything as long as it inputs a signal to the control device 90. For example, when the operating device is a push switch, the electromagnetic 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 slide switches 93a, 93b to control the control device. The boom cylinder 14 and the bucket cylinder 15 can be operated by two systems of 90 and an electric system through the solenoid valve 65. That is, the hydraulic system of the working machine 1 is equipped with a hydraulic system excellent in operability and durability, and in addition, it is possible to perform fine operation and has a two-system operation system with an electrical system excellent in versatility. Prepare. The hydraulic system of the working system in the second embodiment may be applied to a hydraulic system of a traveling system.

  The hydraulic system of the work machine 1 described above includes the input device 93, and the control device 90 controls the solenoid valve 65 in accordance with the operation of the input device 93. Thus, the operator can operate the first hydraulic device 56B by operating the input device 93. Therefore, the first hydraulic pressure is operated by two systems of operating the operating member 58 and operating the hydraulic system via the operating valves 59C and 59D and operating the input device 93 and operating the control device 90 and the electric system via the solenoid valve 65. The device 56B can be operated. That is, the hydraulic system of the working machine 1 is equipped with a hydraulic system excellent in durability and operability, and in addition, it is possible to perform fine operation and has a two-system operation system with an electrical system excellent in versatility. Prepare.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

1 working machine 14 boom cylinder 15 bucket cylinder 45 traveling oil passage 46 working oil passage 51 changing portion 54 first operation member 55 pilot valve 56A first control valve (boom control valve)
56B 2nd control valve (bucket control valve)
58 second operation member 59 pilot valve 64 branch oil passage 65 solenoid valve 66 junction 71 first check valve 72 second check valve 85 first shuttle valve 86 second shuttle valve 87 third shuttle valve 88 fourth shuttle valve 93 Input device P1 1st hydraulic pump

Claims (7)

A hydraulic pump that discharges hydraulic oil,
A first hydraulic device operable by hydraulic fluid,
An operable operating member,
An operating valve having a rod that moves in response to the operation of the operating member, and in which the pressure of hydraulic fluid can be changed in accordance with the movement of the rod;
With solenoid valve which can change pressure of hydraulic fluid,
A change unit changeable into a first state in which one of the operation valve and the solenoid valve is operated, and a second state in which both the operation valve and the solenoid valve are operated;
The hydraulic system of the working machine that is equipped with. The change unit includes a control device that controls the solenoid valve, and an input device that inputs a signal to the control device.
The hydraulic system of a working machine according to claim 1, wherein the control device controls the solenoid valve in accordance with an operation of the input device. And a second hydraulic device operable by hydraulic fluid and different from the first hydraulic device;
The change unit includes a control device that controls the solenoid valve.
The hydraulic system of a working machine according to claim 1, wherein the control device controls the solenoid valve in accordance with the operation of the second hydraulic device. An oil supply passage connecting the operation valve and the first hydraulic device;
The hydraulic system of the working machine according to any one of claims 1 to 3, further comprising: a branch oil passage connected to the solenoid valve and joining the supply oil passage.   The change unit is provided at a junction of the supply oil passage and the branch oil passage, and communicates the operation valve with the first hydraulic device, and the hydraulic oil of the solenoid valve and the first hydraulic device And a shuttle valve capable of switching between the solenoid valve and the second hydraulic device for communicating the hydraulic oil between the operation valve and the first hydraulic device. The hydraulic system of the working machine according to any one of claims 1 to 4. It is provided in the supply oil passage, and allows the flow of hydraulic fluid from the operation valve toward the first hydraulic device, and restricts the flow of hydraulic fluid from the first hydraulic device and the solenoid valve toward the operation valve A first check valve that
Provided in the branch oil passage, and allowing the flow of hydraulic fluid from the solenoid valve to the first hydraulic device, and restricting the flow of hydraulic fluid from the first hydraulic device and the operation valve to the solenoid valve A second check valve,
The hydraulic system of the working machine according to any one of claims 1 to 5, comprising: The first hydraulic device is a bucket control valve capable of operating a bucket cylinder,
The hydraulic system of a working machine according to any one of claims 3 to 6, wherein the second hydraulic device is a boom control valve capable of operating a boom cylinder.

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