JP7210651B2 - Hydraulic system of work equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to hydraulic systems for work machines such as skid steer loaders and compact track loaders.

Conventionally, work machines are operated by either a hydraulic system or an electric system. For example, the work machine disclosed in Patent Document 1 includes an operation member, an operation valve capable of changing the pressure of hydraulic oil output according to the operation of the operation member, and an operating valve capable of being operated by the hydraulic oil output from the operation valve. with hydraulic equipment.
The work machine disclosed in Patent Document 2 includes a control device that outputs a control signal based on the amount of operation of a swingable first switch, and an electromagnetic valve that controls pilot pressure based on the control signal. and a control valve for supplying hydraulic oil to the actuator based on the pilot pressure.

Japanese Patent Application Laid-Open No. 2017-67100 JP 2015-94443 A

In the work machine disclosed in Patent Literature 1, the hydraulic equipment is operated by changing the pressure of hydraulic oil according to the operation of the operating member. On the other hand, in the work machine disclosed in Patent Document 2, the control device controls the electromagnetic valve and operates the actuator according to the operation of the switch. However, like the hydraulic systems of work machines disclosed in Patent Documents 1 and 2, the hydraulic device (actuator) is controlled only by either the hydraulic system or the electrical system. For this reason, it has been impossible to obtain the advantages of both the hydraulic system, which is excellent in durability and operability, and the electric system, which is capable of fine manipulation and excellent in versatility.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic system for a working machine that is 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 work machine includes a hydraulic pump that discharges hydraulic oil, a hydraulic device that is driven by the hydraulic oil, a first hydraulic device that can be operated by the hydraulic oil and controls the hydraulic device, and is operated by an operator. an operating member, an input device that is different from the operating member and is operated by the operator, and a rod that moves according to the operation of the operating member, and that supplies hydraulic oil according to the movement of the rod an operation valve whose pressure can be changed; an electromagnetic valve whose pressure of hydraulic oil can be changed according to the operation of the input device; and the solenoid valve, a first state in which hydraulic oil is supplied from the one to the first hydraulic device to operate the first hydraulic device, and the operator operates the operation member and the When both the input devices are operated to operate both the operation valve and the solenoid valve, the hydraulic oil having the higher pressure among the hydraulic oils supplied by the operating member and the input device is selected as the first hydraulic oil. a changing unit that can be changed to a second state for supplying hydraulic fluid to a hydraulic device and operating the first hydraulic device , wherein the first hydraulic device is operated by hydraulic fluid supplied from the changing unit, A control valve that changes the flow rate of hydraulic oil supplied to the hydraulic equipment to control the hydraulic equipment, and the hydraulic equipment is a boom cylinder or an arm cylinder .

Further, the hydraulic system of the work machine includes a supply oil passage that connects the operation valve and the first hydraulic device, and a branch oil passage that is connected to the solenoid valve and joins the supply oil passage. .
Further, the changing portion is provided at a confluence portion of the supply oil passage and the branch oil passage, communicates the operation valve and the first hydraulic device, and provides a connection between the solenoid valve and the first hydraulic device. A shuttle valve switchable between a first position for regulating hydraulic fluid and a second position for regulating hydraulic fluid between the operation valve and the first hydraulic device to allow communication between the solenoid valve and the first hydraulic device. It has

Further, the changing portion is provided in the supply oil passage and allows hydraulic fluid to flow 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 that regulates the flow of hydraulic oil toward the first hydraulic device; and a second check valve that regulates the flow of hydraulic oil from the operation valve toward the solenoid valve.

Further, the hydraulic system of the work machine is arranged between the confluence of the supply oil passage and the branched oil passage and the first hydraulic device, and the first hydraulic pressure is supplied from the confluence of the supply oil passage to the first hydraulic device. a bypass check valve that allows hydraulic fluid to flow to equipment and prevents hydraulic fluid from flowing from the first hydraulic equipment to a confluence portion of the supply oil passage; a bypass oil passage connected to the inlet side and the outlet side and provided with a throttle.

ADVANTAGE OF THE INVENTION According to this invention, the hydraulic system of the working machine excellent in operability and versatility can be provided.

1 is a schematic diagram of a traveling hydraulic system in a first embodiment; FIG. 1 is a schematic diagram of a working hydraulic system in the first embodiment; FIG. FIG. 5 is a schematic diagram of a first modified example of the hydraulic system of the working system in the first embodiment; FIG. 5 is a schematic diagram of a second modification of the hydraulic system of the working system in the first embodiment; It is a schematic diagram of the hydraulic system of the working system in the second embodiment. 1 is a side view showing a track loader that is an example of a working machine; FIG. FIG. 4 is a side view showing part of the track loader with the cabin raised.

A preferred embodiment of a hydraulic system for a working machine 1 according to the present invention will be described below with reference to the drawings as appropriate.
[First embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 6 shows a side view of a working machine according to the invention. FIG. 6 shows a compact track loader as an example of the work machine. However, the work machine according to the present invention is not limited to a compact track loader, and may be other types of loader work machine such as a skid steer loader. Also, a work machine other than a loader work 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. As shown in FIGS. In the embodiment of the present invention, the front side (left side in FIG. 6) of the driver seated in the driver's seat 8 of the working machine 1 is forward, the rear side (right side in FIG. 6) is rearward, and the left side of the driver (right side in FIG. 6) is 6) is the left side, and the driver's right side (back side in FIG. 6) is the right side. Also, 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 body 2 to the right or left will be described as the outward direction of the body. In other words, the outer side of the fuselage is the width direction of the fuselage and the direction away from the fuselage 2 . The direction opposite to the outer side of the fuselage will be described as the inner side of the fuselage. In other words, the inner side of the body is the width direction of the body and the direction toward the body 2 .

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

The booms 10 are provided on the right and left sides 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 (front end) of the boom 10 so as to be vertically swingable. 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 vertically. The boom cylinder 14 raises and lowers the boom 10 by extending and contracting. The bucket cylinder 15 swings the bucket 11 by expanding and contracting.

The front portions of the left and right booms 10 are connected to each other by a connecting pipe of an irregular shape. The bases (rear portions) of the booms 10 are connected to each other by circular connecting pipes.
A lift link 12, a control link 13 and a boom cylinder 14 are provided on the left and right sides of the fuselage 2 corresponding to the left and right booms 10, respectively.
A lift link 12 is provided longitudinally at the rear of the base of each boom 10 . An upper portion (one end side) of the lift link 12 is pivotally supported near the rear portion of the base of each boom 10 via a pivot shaft (first pivot shaft) 16 so as to be rotatable about a horizontal axis. A lower portion (the other end side) of the lift link 12 is pivotally supported toward the rear portion of the body 2 via a pivot shaft (second pivot shaft) 17 so as to be rotatable about a horizontal axis. The second pivot shaft 17 is provided below the first pivot shaft 16 .

An upper portion of the boom cylinder 14 is pivotally supported via a pivot shaft (third pivot shaft) 18 so as to be rotatable about a horizontal axis. The third pivot shaft 18 is the base of each boom 10 and is provided at the front of the base. A lower portion of the boom cylinder 14 is pivotally supported via a pivot shaft (fourth pivot shaft) 19 so as to be rotatable about a horizontal axis. The fourth pivot shaft 19 is provided near the lower portion of the rear portion of the body 2 and below the third pivot shaft 18 .

The control link 13 is provided forward of the lift link 12 . One end of the control link 13 is pivotally supported via a pivot shaft (fifth pivot shaft) 20 so as to be rotatable about a horizontal axis. The fifth pivot shaft 20 is provided on the body 2 at a position corresponding to the front of the lift link 12 . The other end of the control link 13 is pivotally supported via a pivot shaft (sixth pivot shaft) 21 to be rotatable about a horizontal axis. The sixth pivot shaft 21 is provided on the boom 10 in front of the second pivot shaft 17 and above the second pivot shaft 17 .

By extending 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 end of each boom 10 is moved. rises and falls. 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.

Instead of the bucket 11, another working tool can be attached to the front portion of the boom 10. - 特許庁Other work tools include attachments (preliminary attachments) such as hydraulic crushers, hydraulic breakers, angle blooms, earth augers, pallet forks, sweepers, mowers, and snow blowers.
A connection member 50 is provided on the front portion of the boom 10 on the left side. The connection member 50 is a device that connects the hydraulic equipment mounted on the spare attachment and the first pipe member such as a pipe provided on the boom 10 . Specifically, a first pipe member can be connected to one end of the connection member 50, and a second pipe member connected to the hydraulic equipment of the auxiliary attachment can be connected to the other end. As a result, hydraulic fluid flowing through the first pipe member passes through the second pipe member and is supplied to the hydraulic equipment.

The bucket cylinder 15 is arranged near the front portion of each boom 10 . By extending and contracting the bucket cylinder 15, the bucket 11 is swung.
In this embodiment, crawler type (including semi-crawler type) traveling devices are employed for the left and right traveling devices 5 . A wheel-type traveling device having front and rear wheels may be employed.

Next, the traveling hydraulic system will be described.
As shown in FIG. 1, the hydraulic system includes a first hydraulic pump P1, a left travel motor device (first travel motor device) 31L, a right travel motor device (second travel motor device) 31R, a motor 32, and a traveling drive device 34 .
The first hydraulic pump P<b>1 can discharge hydraulic oil stored in the tank 22 . The first hydraulic pump P1 is a pump driven by the power of the prime mover 32 and is composed of a constant displacement gear pump. The first hydraulic pump P1 discharges hydraulic oil that is mainly used for control. For convenience of explanation, the tank 22 that stores hydraulic oil may be referred to as a hydraulic oil tank. Among the hydraulic fluid discharged from the first hydraulic pump P1, the hydraulic fluid used for control is sometimes called pilot oil, and the pressure of the pilot oil is sometimes called pilot pressure. An oil passage (discharge oil passage) 40 through which hydraulic oil (pilot oil) flows 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 travel motor device 31L and a second travel motor device 31R.

The prime mover 32 is composed of an electric motor, an engine, and the like. In this embodiment, prime mover 32 is an engine. The prime mover 32 may be of 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 includes a drive circuit (left drive circuit) 34L for driving the first travel motor device 31L and a second travel motor device 34L. 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 have travel pumps (travel hydraulic pumps) 53L, 53R, gear shift oil passages 57h, 57i, and a second charge oil passage 57j, respectively. The transmission oil passages 57 h and 57 i are oil passages that connect the travel pumps 53 L and 53 R and the travel motor 36 . The second charge oil passage 57j is an oil passage that is connected to the shift oil passages 57h and 57i and replenishes the shift oil passages 57h and 57i with hydraulic oil from the first hydraulic pump P1.

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 travel pumps 53L and 53R are travel actuators that can be operated by hydraulic fluid. The traveling pumps 53L and 53R have a forward pressure receiving portion 53a and a reverse pressure receiving portion 53b on which pilot pressure acts. 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 swash plate, it is possible to change the outputs of the travel pumps 53L and 53R (discharge amount of hydraulic oil) and the discharge direction of the hydraulic oil.

The first travel motor device 31L is a motor that transmits power to the drive shaft of the travel device 5 provided on the left side of the body 2 . The second travel motor device 31R is a motor that transmits power to the drive shaft of the travel device 5 provided on the right side of the body 2 .
The first travel motor device 31</b>L has a travel motor 36 , a front/rear switching valve 35 , and a travel control valve (hydraulic pressure switching valve) 38 . Hydraulic oil can be supplied to the travel motor 36 , the forward/reverse switching valve 35 and the travel control valve 38 .

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

The second hydraulic pump P2 is installed at a position different from that of the first hydraulic pump P1, and is composed of a constant displacement gear pump. The second hydraulic pump P<b>2 can discharge hydraulic oil stored in the tank 22 . The second hydraulic pump P2 discharges hydraulic fluid that mainly operates the hydraulic actuators.
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 that can switch the flow direction of the hydraulic oil by the pilot pressure of the pilot oil. The control valve 56 also controls (drives) hydraulic devices such as booms, buckets, hydraulic crushers, hydraulic breakers, angle blooms, earth augers, pallet forks, sweepers, mowers, and snow blowers.

The multiple 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 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 for controlling hydraulic devices (hydraulic cylinders, hydraulic motors) attached to spare attachments such as hydraulic crushers, hydraulic breakers, angle blooms, earth augers, pallet forks, sweepers, mowers, and snow blowers. be. In the following description, the first control valve 56A may be called a boom control valve. Also, the second control valve 56B may be called 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. The first control valve 56A and the second control valve 56B switch to a neutral position, a first position different from the neutral position, and a second position different from the neutral position and the first position, depending on the pilot pressure. The first control valve 56A can be operated by the pressure difference of hydraulic fluid acting on the pressure receiving portions on one side and the other side of the first control valve 56A. In addition, the second control valve 56B can be operated by the pressure difference of hydraulic fluid acting on the pressure receiving portions 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 through an oil passage, and the bucket cylinder 15 is connected to the second control valve 56B through an oil passage.

An oil supply/discharge passage 83 is connected to the third control valve 56C. One end of the oil supply/drainage passage 83 is connected to the supply/drainage port of the third control valve 56C, the middle portion of the oil supply/drainage passage 83 is connected to the connection member 50, and the other end of the oil supply/drainage passage 83 is It is connected to the hydraulic equipment of the spare attachment. Specifically, the oil supply/drainage passage 83 includes a first oil supply/drainage passage 83 a that connects the first supply/drainage port of the third control valve 56</b>C and the first port of the connection member 50 . Further, the oil supply/drainage passage 83 includes a second oil supply/drainage passage 83b that connects the second supply/drainage 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 oil supply/drainage passage 83a, or from the third control valve 56C toward the second oil supply/drainage passage 83b. Hydraulic oil can flow through

As shown in FIGS. 1 and 2, an operation related to traveling of the work implement 1 (running operation) and an operation related to work (work operation) are performed by a first operating device 47 provided on the left side of the driver's seat 8 and the operator's seat 8. It is performed by the second operating device 48 provided on the right side. In other words, the first operating device 47 and the second operating device 48 are the hydraulic devices of the travel system (the travel motor 36, the travel pumps 53L and 53R), the hydraulic devices of 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 operating member 54 is a lever capable of performing a first operation of moving forward and backward, and a second operation of moving left and right (machine width direction) different from forward and backward. In other words, the first operating member 54 is a lever that can be moved in one direction (eg, forward, left) and in another direction (eg, backward, right).

In the first operating member 54, the first operation is assigned to the travel operation, and the second operation is assigned to the work operation. That is, the first operating member 54 serves both as an operating member for traveling (running operating member) and as an operating member for work (working operating member). Note that the first operation member 54 is not limited to a lever as long as it can independently perform at least the first operation and the second operation.

A plurality of pilot valves 55 are provided below the first operating member 54 . A plurality of pilot valves 55 can change the pressure of hydraulic fluid according to the operation of the first operating member 54 . Specifically, the pilot valve 55 has a rod that contacts the first operating member 54 . In other words, the pressure of the hydraulic fluid output from the pilot valve 55 is changed by pushing the rod according to the operation of the first operating member 54 . The plurality of pilot valves 55 are pilot valve 55A, pilot valve 55B, pilot valve 55C and pilot valve 55D. Pilot valve 55A, pilot valve 55B, pilot valve 55C, and pilot valve 55D are connected to discharge oil passage 40 .

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

The pilot valve 55C is a valve that is operated 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 is operated by the right operation of the second operation (right and left 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 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 operating member 58 is a lever capable of performing a first operation of moving forward and backward, and a second operation of moving left and right (machine width direction) different from forward and backward. In other words, the second operating member 58 is a lever that can be moved in one direction (eg, forward, left) and in another direction (eg, backward, right).

In the second operating member 58, the first operation is assigned to the travel operation, and the second operation is assigned to the work operation. In other words, the second operating member 58 serves both as an operating member for traveling (running operating member) and as an operating member for work (working operating member). In addition, the second operation member 58 is not limited to a lever as long as it can independently perform at least the first operation and the second operation.

A plurality of pilot valves 59 are provided below the second operating member 58 . A plurality of pilot valves 59 can change the pressure of hydraulic fluid according to the operation of the second operating member 58 . Specifically, the pilot valve 59 has a rod that contacts the second operating member 58 . In other words, the pressure of the hydraulic fluid output from the pilot valve 59 is changed by pushing the rod according to the operation of the second operating member 58 . The plurality of pilot valves 59 are pilot valve 59A, pilot valve 59B, pilot valve 59C and pilot valve 59D. Pilot valve 59A, pilot valve 59B, pilot valve 59C, and pilot valve 59D are connected to discharge oil passage 40 .

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

The pilot valve 59C is a valve that is operated by the left operation of the first operation (right and left operation), and the pressure of the hydraulic oil to be output changes according to the amount of operation (operation) of the left operation. The pilot valve 59D is a valve that is operated by the right operation of the second operation (right and left 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 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 corresponding 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 operations. For convenience of explanation, the pilot valve 55A, the pilot valve 55B, the pilot valve 59A, and the pilot valve 59B are sometimes referred to as travel pilot valves. Among the travel pilot valves, the pilot valve 55A that is operated by the first operating member 54 in one direction (for example, front) is referred to as a "first pilot valve", and the first operating member 54 is operated in the other direction (for example, rearward). The pilot valve 55B operated by the second operating member 58 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". The pilot valve 59B that is operated by the other direction (for example, backward) of the 2 operation member 58 is called a "fourth pilot valve".

Next, the relationship between the travel pilot valve, the work pilot valve, and the hydraulic equipment will be described. Symbols “W1”, “W2”, “D1”, and “D2” shown in FIGS. 1 and 2 indicate connection destinations of oil passages.
The travel pilot valve and the travel pumps 53L and 53R, which are one of travel system hydraulic devices (travel hydraulic devices), are connected by a travel oil passage 45 . The travel oil passage 45 has a first travel oil passage 45a, a second travel oil passage 45b, a third travel oil passage 45c, and a fourth travel oil passage 45d. The first travel oil passage 45a is an oil passage that connects the first pilot valve 55A and the forward pressure receiving portion 53a of the travel pump 53L. The second travel oil passage 45b is an oil passage that connects the second pilot valve 55B and the reverse pressure receiving portion 53b of the travel pump 53L. The third travel oil passage 45c is an oil passage that connects the third pilot valve 59A and the forward pressure receiving portion 53a of the travel pump 53R. The fourth travel oil passage 45d is an oil passage that connects the fourth pilot valve 59B and the reverse pressure receiving portion 53b of the travel 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 rearward, 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 rearward, 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 moves forward at a speed proportional to the amount of swinging of the first operating member 54 and the second operating member 58. As a result, the working machine 1 moves forward straight. 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 amount of swinging of the first operating member 54 and the second operating member 58, and as a result , the working machine 1 moves straight backward.

When one of the first operating member 54 and the second operating member 58 is swung forward and the other is swung rearward, the left travel motor 36 and the right travel motor 36 move in different directions. Rotate, and as a result, the work implement 1 turns to the right or to the left.
As described above, by moving the first operating member 54 back and forth and moving the second operating member 58 back and forth, the work machine 1 can be moved forward, backward, turned right, and turned left.

The work pilot valve and the control valve 56 , which is one of the work system hydraulic devices (work hydraulic devices), 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 work 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 leftward, the pilot valve 55C is operated to set the pilot pressure of the pilot oil output from the pilot valve 55C. 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 to set the pilot pressure of the pilot oil output from the pilot valve 59C. This pilot pressure acts on the pressure receiving portion of the second control valve 56B, the bucket cylinder 15 is contracted, and the bucket 11 is swung. 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. This pilot pressure acts on the pressure receiving portion of the second control valve 56B, the bucket cylinder 15 expands, and the bucket 11 dumps.

Therefore, by moving the first operating member 54 left and right and moving the second operating member 58 left and right, it is possible to carry out work operations such as raising and lowering the boom 10 and dumping or scooping the bucket.
A hydraulic system includes a hydraulic pump, a first hydraulic device, a second hydraulic device, an operating member, and an operating valve. In this 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 this 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 portion 76a and a second pressure-receiving portion 76b, and is operable by the pressure difference of hydraulic fluid acting on the first pressure-receiving portion 76a and the second pressure-receiving portion 76b. . Specifically, the 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 is moved to a neutral position, a first position different from the neutral position, a neutral position and a first It switches to a second position different from the position.

The hydraulic system has a branch oil passage 64 and an electromagnetic valve 65 . The branch oil passage 64 includes a first branch oil passage 64a that joins the third work oil passage 46c and a second branch oil passage 64b that joins the fourth work oil passage 46d.
The electromagnetic valve 65 is an electromagnetic proportional valve (proportional valve) whose opening can be changed by energizing a solenoid. In other words, the solenoid valve 65 can change the flow rate of the hydraulic oil passing through it. 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 electromagnetic valve 65 has an inlet side connected to the first hydraulic pump P<b>1 and an outlet side connected to the branch oil passage 64 . More specifically, the first electromagnetic valve 65a is connected to the first branch oil passage 64a on the outlet side. The second solenoid valve 65b has an outlet side connected to the second branch oil passage 64b. According to the solenoid valve 65, when the degree of opening is changed from the fully closed state, the work oil passages 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. As shown in FIG. Specifically, the hydraulic oil discharged by the first hydraulic pump P1 can be merged with the working oil passages 46c and 46d via the solenoid valve 65 and the branch oil passage 64, respectively. This allows the hydraulic oil discharged from the hydraulic pump P1 to act on the second control valve 56B.

The hydraulic system has a modification section 51 . The changing unit 51 can be changed between a first state in which either one of the pilot valves 59C, 59D and the solenoid valve 65 is 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 portion 66 of the working oil passage 46 and the branch oil passage 64 . The shuttle valve 86 is provided at a second confluence portion 66b where the fourth working oil passage 46d and the second branch oil passage 64b join.

When either the pilot valve 59C or the solenoid valve 65 is actuated (in the first state), the shuttle valve 85 reduces the hydraulic oil pressure set by the actuated pilot valve 59C or the solenoid valve 65 to the first It 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 reduces the hydraulic oil pressure set by the actuated pilot valve 59D or the solenoid valve 65 to the second pressure. It is transmitted to the pressure receiving portion 76b.

Further, when both the pilot valve 59C and the solenoid valve 65 are actuated (in the second state), the shuttle valve 85 selects which of the actuated pilot valve 59C or the solenoid valve 65, which has the higher hydraulic oil pressure, It is transmitted to the first pressure receiving portion 76a.
When both the pilot valve 59D and the solenoid valve 65 are actuated (when they are in the second state), the shuttle valve 85 selects whichever of the actuated pilot valve 59D or the solenoid valve 65, which has the higher pressure of the hydraulic fluid, to the second state. It is transmitted to the pressure receiving portion 76b.

Therefore, when the change unit 51 is in the first state, the change unit 51 changes the hydraulic oil pressure set by the operation valves 59C and 59D or the hydraulic oil pressure set by the solenoid valve 65 to the control valve 56 or the like. 1 hydraulic equipment to operate the first hydraulic equipment. On the other hand, when the change unit 51 is in the second state, the change unit 51 changes either the hydraulic oil pressure set by the operation valves 59C, 59D or the hydraulic oil pressure set by the solenoid valve 65 to the control valve 56 or the like. It can be applied to the first hydraulic equipment to operate the first hydraulic equipment.

The changing unit 51 also includes a control device 90 . A 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 devices connected to the control device 90 . Specifically, the controller 90 is connected to an angle detector 91 that detects the angle of the boom 10 . The controller 90 can be switched to 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 horizontal control mode is performed by a switch 92 connected to the controller 90 . The switch 92 is a member that instructs the controller 90 to switch to the horizontal control mode. When the switch 92 is depressed, a signal is output to the controller 90 to switch to the horizontal control mode. On the other hand, if the switch 92 is pressed again, the horizontal control mode is canceled. The switch 92 is a push button switch 92 such as a momentary switch or an alternate switch. Note that the switch 92 is not limited to the push button switch 92 of the momentary switch or the alternate switch, and any switch 92 that outputs a signal to the control device 90 may be used.

When the horizontal control mode is canceled, hydraulic fluid is applied to the second control valve 56B from the pilot valves 59C and 59D. Also, the control device 90 closes the electromagnetic valve 65 . On the other hand, when shifting to the horizontal control mode, the control device 90 controls the solenoid valve 65 to apply hydraulic oil from the solenoid valve 65 to the second control valve 56B. In other words, either the hydraulic fluid of the pilot valves 59C, 59D or the hydraulic fluid of the solenoid valve 65 acts on the second control valve 56B, which is the first hydraulic device.

In the horizontal control mode, the controller 90 operates the bucket 11 according to the boom angle detected by the angle detector 91 . In other words, the control device 90 controls the solenoid valve 65 according 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 movement angle of the boom 10 after 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 performs the squeezing operation by the same value as the movement angle of the boom 10 . On the other hand, when the boom cylinder 14 extends and the boom 10 rises, the control device 90 controls the electromagnetic 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 control device 90 controls the solenoid valve 65 according to the operation of the first control valve 56A. Thereby, the movement angle of the bucket 11 connected to the second control valve 56B can be controlled via the boom cylinder 14 according to the movement angle of the boom 10 connected to the first control valve 56A. Therefore, since the above-described 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 only needs to be operated according to the movement angle of the boom 10, and instead of the angle detection section 91, a detection device for measuring the extension and retraction distances of the boom cylinder 14 may be provided. Further, a pressure sensor is provided in the work 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 working oil output from the operation valves 59C and 59D. you can go

Shuttle valves 85 and 86 include first shuttle valve 85 and second shuttle valve 86 . The confluence portion 66 includes a first confluence portion 66a and a second confluence portion 66b.
The first shuttle valve 85 is provided at a first confluence portion 66a where the third work oil passage 46c and the first branch oil passage 64a join. The first shuttle valve 85 communicates between the pilot valve 59C and the second control valve 56B, and has a first position for regulating hydraulic fluid between the first electromagnetic valve 65a and the second control valve 56B, It also has a second position that restricts hydraulic fluid to and from the control valve 56B and communicates the first solenoid valve 65a with the second control valve 56B. That is, when the hydraulic fluid pressure acting on the first shuttle valve 85 from the pilot valve 59C is higher than the hydraulic fluid pressure acting on the first shuttle valve 85 from the first electromagnetic valve 65a, the pilot valve 59C is set. Hydraulic oil pressure acts on the first pressure receiving portion 76a. In such a case, hydraulic fluid acting on the first shuttle valve 85 from the first electromagnetic valve 65a does not apply pressure to the first pressure receiving portion 76a. On the other hand, when the hydraulic fluid pressure acting on the first shuttle valve 85 from the first electromagnetic valve 65a is greater than the hydraulic fluid pressure acting on the first shuttle valve 85 from the pilot valve 59C, the first electromagnetic valve 65a The set hydraulic oil pressure acts on the first pressure receiving portion 76a. In such a case, hydraulic fluid 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 at a second confluence portion 66b where the fourth working oil passage 46d and the second branch oil passage 64b join. The second shuttle valve 86 communicates between the pilot valve 59D and the second control valve 56B, and has a first position for regulating hydraulic fluid between the second solenoid valve 65b and the second control valve 56B, It has a second position that regulates the flow of hydraulic fluid to and from the control valve 56B and communicates the second solenoid valve 65b with the second control valve 56B. That is, when the hydraulic fluid pressure acting on the second shuttle valve 86 from the pilot valve 59D is higher than the hydraulic fluid pressure acting on the second shuttle valve 86 from the second solenoid valve 65b, the pilot valve 59D is set. The hydraulic oil pressure acts on the second pressure receiving portion 76b. In such a case, hydraulic fluid acting on the second shuttle valve 86 from the second electromagnetic valve 65b does not apply pressure to the second pressure receiving portion 76b. On the other hand, when the pressure of hydraulic fluid acting on the second shuttle valve 86 from the second electromagnetic valve 65b is higher than the pressure of hydraulic fluid acting on the second shuttle valve 86 from the pilot valve 59D, the second electromagnetic valve 65b The set hydraulic oil pressure acts on the second pressure receiving portion 76b. In such a case, hydraulic fluid 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 having the higher pressure among the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64 can be caused to act on the second control valve 56B. On the other hand, it is possible to prevent the hydraulic oil having a lower pressure from acting on the second control valve 56B, out of the hydraulic oil in the working oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64. Therefore, either the pilot valves 59C, 59D side or the electromagnetic 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 are provided with bypass check valves 96, respectively. The bypass check valve 96 permits hydraulic fluid to flow from the pilot valves 59C and 59D to the second control valve 56B and blocks hydraulic fluid to flow from the second control valve 56B to the pilot valves 59C and 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 in the bypass oil passage 95 . The throttle 97 reduces the flow rate of hydraulic oil. The throttle 97 is configured, for example, by making a part of the bypass oil passage 95 thinner than the other part. In other words, the cross-sectional area of the portion through which the hydraulic oil flows in the bypass oil passage 95 is made smaller than the other portions. Note that the above configuration may be applied to a traveling 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 work oil passages 46c, 46d between the confluence portion 66 of the work oil passages 46c, 46d and the branch oil passage 64 and the pilot valves 59C, 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 hydraulic fluid to flow from the pilot valves 59C and 59D toward the confluence portion 66, and allows hydraulic fluid to flow from the confluence 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 work oil passage 46c and the second branch oil passage 64b connected to the fourth work oil passage 46d. there is The second check valve 72 allows hydraulic fluid to flow from the electromagnetic valve 65 to the confluence portion 66 and regulates the hydraulic fluid flow from the confluence portion 66 to the electromagnetic valve 65 . This allows hydraulic fluid to flow from the pilot valves 59C, 59D toward the second control valve 56B, and prevents hydraulic fluid from flowing from the second control valve 56B and solenoid valve 65 toward the pilot valves 59C, 59D. can be prevented. In addition, hydraulic fluid flowing from the electromagnetic valve 65 side toward the second control valve 56B side is permitted, and hydraulic fluid flowing toward the electromagnetic valve 65 side from the second control valve 56B and the pilot valves 59C and 59D side is blocked. can be done. Therefore, it is possible to prevent backflow of 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 backflow of hydraulic oil from the side of the second control valve 56B and the pilot valves 59C and 59D to the electromagnetic valve 65. FIG. In the modified example described above, 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 the control of the control device 90. Also, 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 first electromagnetic valve 65a has an inlet side connected to the second working oil passage 46b and an outlet side connected 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 closed state, the hydraulic oil output from the pilot valve 55D is passed 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, the boom cylinder 14 contracts, and the boom 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 is contracted, and the bucket 11 is squeezed. That is, according to the above configuration, the control device 90 controls the opening degree of the first solenoid valve 65a, so that the scooping operation of the bucket 11 can be controlled according to the descent of the boom 10. FIG. That is, horizontal control of the bucket 11 is possible.

The hydraulic system of the work machine 1 described above includes a hydraulic pump P1, a first hydraulic device 56B, an operation member 58, operation valves 59C and 59D, an electromagnetic valve 65, a control device 90, and a change section 51. I have. As a result, hydraulic fluid can be applied to the first hydraulic device 56B from two different systems, the operation valves 59C and 59D and the solenoid valve 65. As shown in FIG. Therefore, apart from the operation of the operating member 58 by the operator, the control device 90 opens the solenoid valve 65 to apply hydraulic oil to the first hydraulic device 56B, thereby easily operating the first hydraulic device 56B. can be done.

The hydraulic system of work machine 1 also includes a second hydraulic device 56A, and controller 90 controls electromagnetic valve 65 in accordance with the operation of 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, a horizontal control function can be introduced into the hydraulic system of the working machine 1. FIG.

The hydraulic system of the work machine 1 also 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, 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 to which the electromagnetic valve 65 is provided. can work. Therefore, apart from the operation of the operating member 58 by the operator, the control device 90 opens the solenoid valve 65 to apply the hydraulic oil to the first hydraulic device 56B via the branch oil passage 64, thereby facilitating the first Hydraulic equipment 56B can be operated.

The changing section 51 also includes shuttle valves 85 and 86 . As a result, of the hydraulic oil flowing through the supply oil passages 46c and 46d and the hydraulic oil flowing through the branch oil passage 64, the hydraulic oil having the higher pressure can be caused to act on the first hydraulic device 56B. On the other hand, it is possible to block the flow of the hydraulic oil having the lower pressure between the hydraulic oil in the supply oil passages 46c and 46d and the hydraulic oil in the branch oil passage 64. Therefore, it is possible to operate the first hydraulic device 56B from either one of the operation valves 59C and 59D and the electromagnetic valve 65 .

The hydraulic system of the work machine 1 also includes a first check valve 71 and a second check valve 72 . This allows hydraulic fluid to flow from the side of the operation valves 59C and 59D toward the side of the first hydraulic device 56B, and prevents hydraulic fluid from flowing from the side of the first hydraulic device 56B and the electromagnetic valve 65 to the side of the operation valves 59C and 59D. can be prevented. Also, hydraulic fluid flowing from the solenoid valve 65 side toward the first hydraulic device 56B side is permitted, and hydraulic fluid flowing from the first hydraulic device 56B and the operation valves 59C, 59D side toward the solenoid valve 65 side is blocked. can be done. Therefore, it is possible to prevent backflow of 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 backflow of hydraulic oil from the side of the first hydraulic device 56B and the operation valves 59C and 59D to the solenoid valve 65. FIG.

The first hydraulic device 56B is the bucket control valve 56B, and the second hydraulic device 56A is the boom control valve 56A. As a result, the operating angle of the bucket 11 connected to the bucket control valve 56B via the bucket cylinder 15 is controlled 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, a horizontal control function can be introduced into the hydraulic system of the working machine 1. FIG.
[Second embodiment]
FIG. 5 shows a hydraulic system according to a second embodiment of the invention. In addition, the same code|symbol is attached|subjected about the structure similar to 1st Embodiment, and the description is abbreviate|omitted.

Now, the hydraulic system includes a hydraulic pump, a first hydraulic device, an operating member, and an operating valve. In this embodiment, the hydraulic pump is the first hydraulic pump P1. The first hydraulic device is the first control valve 56A and the 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 and 59D. The hydraulic system also has a supply oil passage. In this embodiment, the supply oil passages include the working oil passage 46a connecting the pilot valve 55C and the first control valve 56A, the second working oil passage 46b connecting the pilot valve 55D and the first control valve 56A, and the pilot valve A third working fluid passage 46c connects the second control valve 56B with the pilot valve 59C, and a fourth working fluid passage 46d connects 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 is operable by a pressure difference between hydraulic fluid acting on the first pressure-receiving portion 75a and the second pressure-receiving portion 75b. be. Specifically, the first pressure receiving portion 75a is connected to the first working oil passage 46a. The second working oil passage 46b is connected to the second pressure receiving portion 75b. That is, the first control valve 56B is moved to a neutral position, a first position different from the neutral position, a neutral position and a first It switches to a second position different from the position.

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

The change section 51 has shuttle valves 87 and 88 . The shuttle valves 87, 88 are provided at the confluence portion 66 of the work oil passages 46a, 46b and the branch oil passage 64, communicate the pilot valves 55C, 55D and the first control valve 56A, and connect the solenoid valve 65 and the first control valve 56A. A first position that restricts hydraulic fluid to the control valve 56A, and a second position that restricts hydraulic fluid to the pilot valves 55C, 55D and the first control valve 56A and communicates the solenoid valve 65 and 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 confluence portion 66 includes a third confluence portion 66c and a fourth confluence portion 66d.

The third shuttle valve 87 is provided at a third confluence portion 66c where the first work oil passage 46a and the third branch oil passage 64c join. The third shuttle valve 87 communicates between the pilot valve 55C and the first control valve 56A, and has a first position for regulating hydraulic fluid between the third solenoid valve 65c and the first control valve 56A, It has a second position that regulates the flow of hydraulic fluid to and from the control valve 56A and communicates the third solenoid valve 65c with 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 higher than the pressure of the hydraulic fluid acting on the third shuttle valve 87 from the third electromagnetic valve 65c, the pilot valve 55C is set. Hydraulic oil pressure acts on the first pressure receiving portion 75a. In such a case, hydraulic fluid acting on the third shuttle valve 87 from the third electromagnetic valve 65c does not apply pressure to the first pressure receiving portion 75a. On the other hand, when the pressure of hydraulic fluid acting on the third shuttle valve 87 from the third electromagnetic valve 65c is higher than the pressure of hydraulic fluid acting on the third shuttle valve 87 from the pilot valve 55C, the third electromagnetic valve 65c The set hydraulic oil pressure acts on the first pressure receiving portion 75a. In such a case, hydraulic fluid 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 a fourth confluence portion 66d where the second working oil passage 46b and the fourth branch oil passage 64c join. The fourth shuttle valve 88 communicates between the pilot valve 55D and the first control valve 56A, and has a first position for regulating hydraulic fluid between the fourth electromagnetic valve 65d and the first control valve 56A, It has a second position for regulating hydraulic fluid to and from the control valve 56A and communicating between the fourth solenoid valve 65d and the first control valve 56A. That is, when the pressure of hydraulic fluid acting on the fourth shuttle valve 88 from the pilot valve 55D is higher than the pressure of hydraulic fluid acting on the fourth shuttle valve 88 from the fourth electromagnetic valve 65d, the pilot valve 55D is set. Hydraulic oil pressure acts on the second pressure receiving portion 75b. In such a case, hydraulic fluid acting on the fourth shuttle valve 88 from the fourth solenoid valve 65d does not apply pressure to the second pressure receiving portion 75b. On the other hand, when the pressure of hydraulic fluid acting on the fourth shuttle valve 88 from the fourth electromagnetic valve 65d is greater than the pressure of hydraulic fluid acting on the fourth shuttle valve 88 from the pilot valve 55D, the fourth electromagnetic valve 65d The set hydraulic oil pressure acts on the second pressure receiving portion 75b. In such a case, hydraulic fluid 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 are provided with bypass check valves 96, respectively. A bypass check valve 96 allows hydraulic fluid to flow from the pilot valve to the first control valve and blocks hydraulic fluid to flow 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 in the bypass oil passage 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, 93b. Specifically, the input device 93 is an operation device capable of changing the amount of hydraulic oil supplied to the first control valve 56A and the second control valve 56B, that is, the amount of hydraulic oil supplied from the solenoid valve 65. be. In other words, the input device 93 is an operating device that sets the opening degree of the electromagnetic valves 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 (the amount of operation), such as slide volume. Operation signals of the slide switches 93 a and 93 b 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 electromagnetic 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 electromagnetic valve 65b. That is, the bucket 11 can be operated via the second control valve 56B and the bucket cylinder 15 by operating the slide switch 93a. Further, when the slide switch 93b is slid in one direction, the control device 90 controls to open the third electromagnetic valve 65c associated with the slide switch 93b. When the slide switch 93b is slid in the other direction, the controller 90 controls to open the fourth electromagnetic valve 65d. That is, the boom 10 can be operated via the first control valve 56A and the boom cylinder 14 by operating the slide switch 93b. Note that 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. FIG. For example, if 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. Moreover, 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 working 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 and 59D and the plurality of slide switches 93a and 93b to operate the control device. The boom cylinder 14 and the bucket cylinder 15 can be operated by the two systems, 90 and an electric system via the solenoid valve 65 . That is, the hydraulic system of the working machine 1 has two operating systems: a hydraulic system that is excellent in operability and durability, and an electric system that is capable of fine operation and excellent in versatility. Prepare. The working hydraulic system in the second embodiment may be applied to a traveling hydraulic system.

The hydraulic system of the work machine 1 described above includes an input device 93 , and the control device 90 controls the electromagnetic valve 65 according to the operation of the input device 93 . Thereby, the operator can operate the first hydraulic device 56B by operating the input device 93 . For this reason, the two systems of the hydraulic system via the operation valves 59C and 59D by operating the operation member 58 and the electric system via the control device 90 and the solenoid valve 65 by operating the input device 93 are configured to provide the first hydraulic pressure. Device 56B can be operated. That is, the hydraulic system of the working machine 1 has two operating systems: a hydraulic system that is excellent in durability and operability, and an electric system that is capable of fine operation and excellent in versatility. Prepare.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

Reference Signs List 1 working machine 14 boom cylinder 15 bucket cylinder 45 travel oil passage 46 work oil passage 51 changing portion 54 first operating member 55 pilot valve 56A first control valve (boom control valve)
56B Second control valve (bucket control valve)
58 second operating member 59 pilot valve 64 branch oil passage 65 solenoid valve 66 confluence portion 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 (5)

a hydraulic pump that discharges hydraulic oil;
a hydraulic device driven by hydraulic fluid;
a first hydraulic device operable by hydraulic fluid to control said hydraulic device ;
an operating member operated by an operator;
an input device, which is a member different from the operation member and is operated by the operator;
an operation valve having a rod that moves according to the operation of the operation member, and that can change the pressure of hydraulic oil according to the movement of the rod;
a solenoid valve capable of changing the pressure of the hydraulic oil according to the operation of the input device;
When the operator operates one of the operation member and the input device to operate one of the operation valve and the electromagnetic valve, the one supplies hydraulic oil to the first hydraulic device, In a first state in which the first hydraulic device is operated, and when the operator operates both the operation member and the input device to operate both the operation valve and the electromagnetic valve, the operation member and the input a changing unit capable of changing to a second state of supplying hydraulic fluid having a higher pressure among hydraulic fluids supplied by the device to the first hydraulic device and operating the first hydraulic device;
with
The first hydraulic device is a control valve that is operated by hydraulic fluid supplied from the changing unit to change the flow rate of hydraulic fluid supplied to the hydraulic device to control the hydraulic device,
A hydraulic system for a working machine, wherein the hydraulic device is a boom cylinder or an arm cylinder . a supply oil passage connecting the operation valve and the first hydraulic device;
2. The hydraulic system for a work machine according to claim 1, further comprising a branch oil passage connected to said solenoid valve and joining said supply oil passage. The change portion is provided at a confluence portion of the supply oil passage and the branch oil passage, communicates the operation valve and the first hydraulic device, and supplies hydraulic fluid to the solenoid valve and the first hydraulic device. and a second position for regulating hydraulic fluid between the operating valve and the first hydraulic device and communicating the electromagnetic valve and the first hydraulic device. The hydraulic system for a work machine according to claim 2. The changing portion is provided in the supply oil passage, and allows hydraulic fluid to flow from the operation valve toward the first hydraulic device, and operates from the first hydraulic device and the solenoid valve toward the operation valve. a first check valve that regulates the flow of oil;
provided in the branch oil passage, allowing hydraulic fluid to flow from the solenoid valve to the first hydraulic device, and restricting hydraulic fluid to flow from the first hydraulic device and the operation valve to the solenoid valve a second check valve for
The hydraulic system of the work machine according to claim 2, comprising: is disposed between the confluence of the supply oil passage and the branched oil passage and the first hydraulic device, and permits hydraulic oil to flow from the confluence of the supply oil passage to the first hydraulic device a bypass check valve that blocks the flow of hydraulic oil from the first hydraulic device to the junction of the supply oil passages;
a bypass oil passage connected to the inlet side and outlet side of the bypass check valve in the supply oil passage and provided with a throttle;
The hydraulic system for a work machine according to any one of claims 2 to 4, comprising:

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