JP2016118154A - Service car - Google Patents

Abstract

A hydraulic system for driving a cooling fan and a flow path system for supplying hydraulic oil to a hydraulic actuator are configured at low cost. A radiator that cools cooling water of an engine, a dust net disposed outside the fuselage from the radiator, a cooling fan that is disposed inside the fuselage and supplies cooling air to the radiator, and a cooling fan are provided. And a hydraulic motor M to be driven. A hydraulic pump P that supplies hydraulic oil to hydraulic actuators 62, 66, and 69 provided in the traveling machine body is provided, and hydraulic oil from the hydraulic pump P is selected as one of the hydraulic actuators 62, 66, and 69 and the hydraulic motor M. A switching valve 72 is provided. [Selection] Figure 7

Description

  The present invention relates to a work vehicle in which a cooling fan for supplying cooling air to a radiator is driven by a hydraulic motor.

  Taking a combine as an example of a work vehicle, when air is sucked by a cooling fan during work, dust such as straw adsorbs to the dust proof net of the radiator, and cooling performance may deteriorate. In order to suppress such an inconvenience, Patent Document 1 discloses a technique in which a cooling fan is reversed at a set time interval to blow off dust such as straw attached to a dust-proof net.

  In Patent Document 1, an electromagnetic valve that controls hydraulic oil supplied from a hydraulic pump to a hydraulic motor is provided. The hydraulic valve is operated by switching the flow of hydraulic oil supplied to the hydraulic motor by operating the electromagnetic valve every set time. A technique for switching the rotation direction of a motor is shown.

  Patent Document 2 discloses a technique for switching between normal rotation and reverse rotation of a cooling fan by operating a switching valve, which is different from the purpose of blowing dust such as straw. In Patent Document 2, a pair of flow paths of a hydraulic motor are provided via an orifice between a forward rotation position (forward rotation position) where forward rotation is performed in a switching valve and a reverse rotation position (reverse rotation position) where reverse rotation is performed. A rotation free position (free rotation position) for communication is shown.

JP-A-8-144755 Japanese Patent Laid-Open No. 2004-251124

  In the case of a combine equipped with a plurality of types of hydraulic actuators, a hydraulic pump and a control valve are required to operate the plurality of actuators. Considering a hydraulic circuit for driving the cooling fan, it is ideal to provide a dedicated hydraulic pump for supplying hydraulic oil to the hydraulic motor that drives the cooling fan.

  However, in the configuration including the hydraulic pump for supplying the hydraulic oil to the hydraulic actuator and the hydraulic pump for supplying the hydraulic oil to the hydraulic motor that drives the cooling fan, the drive configuration for driving each hydraulic pump Therefore, the transmission configuration is complicated and the cost is increased.

  Reference 2 shows a configuration including a dedicated hydraulic pump for supplying hydraulic oil to a hydraulic motor that drives a cooling fan.

  An object of the present invention is to inexpensively configure a flow path system that supplies hydraulic oil to a hydraulic motor that drives a cooling fan and a hydraulic actuator.

A feature of the present invention is that a radiator that cools cooling water of an engine, a dust net disposed outside the body of the radiator from the radiator, a cooling fan that is disposed inside the body of the radiator and supplies cooling air to the radiator, A hydraulic motor for driving the cooling fan,
A hydraulic pump that supplies hydraulic oil to a hydraulic actuator provided in the airframe, and a switching valve that selectively supplies hydraulic oil from the hydraulic pump to one of the hydraulic actuator and the hydraulic motor. is there.

According to this configuration, the cooling oil can be driven by supplying the hydraulic oil from the hydraulic pump to the hydraulic motor by the switching valve, and the hydraulic actuator can be driven by supplying the hydraulic oil to the hydraulic actuator by the switching valve. In this configuration, the hydraulic oil is not supplied to the hydraulic motor when the hydraulic actuator is driven, so the cooling fan stops. However, when the hydraulic actuator is stopped, the hydraulic oil can be supplied to the hydraulic motor. It is possible to drive, and it is not necessary to provide a dedicated hydraulic pump for supplying hydraulic oil to the hydraulic motor that drives the cooling fan.
Therefore, a hydraulic system that drives the cooling fan and a flow path system that supplies hydraulic oil to the hydraulic actuator are configured at low cost.

  In the present invention, the switching valve can be switched between a first position for supplying hydraulic oil from the hydraulic pump to the hydraulic motor and a second position for supplying hydraulic oil from the hydraulic pump to the hydraulic actuator. It may be configured.

  According to this, hydraulic fluid can be supplied to the hydraulic motor and the hydraulic actuator by using a switching valve that can be operated between the first position and the second position.

  The present invention may include a control device that sets the switching valve to the second position when the hydraulic actuator is driven and sets the switching valve to the first position when the hydraulic actuator is stopped.

  According to this, for example, only when the control device detects an operation to operate the hydraulic actuator, the control device is set to the second position to operate the hydraulic actuator and not to operate the hydraulic actuator. It becomes possible to continue the driving of the cooling fan by setting the switching valve to the first position.

  In the present invention, when the switching valve is set to the second position, the switching valve may be provided with a rotation allowing portion that allows rotation due to inertia of the hydraulic motor.

  The hydraulic motor is provided with a pair of flow paths, and the hydraulic motor is driven by hydraulic fluid flowing from one flow path to the other. When switching to a situation where hydraulic oil is not supplied, the cooling fan Due to the inertia, the hydraulic motor functions like a hydraulic pump and the state where the hydraulic oil flows through the pair of flow paths continues. From this point of view, by providing a rotation allowance portion at the second position of the switching valve, when the switching valve is operated from the first position to the second position, cooling is performed even when hydraulic oil is not supplied to the hydraulic motor. The fan can be rotated by inertia, and the supply of cooling air to the radiator is not stopped.

  In the present invention, the switching valve includes a pair of ports for discharging and receiving hydraulic oil to and from the hydraulic motor, and the rotation permitting portion can circulate the hydraulic oil between the pair of ports. You may be comprised with the flow path to make.

  According to this, when the switching valve is operated from the first position to the second position, the hydraulic oil can be circulated between the ports connected to the pair of flow paths of the hydraulic motor. That is, the rotation by the inertia of the cooling fan is realized by a relatively simple configuration in which a flow path for flowing hydraulic oil between the two ports is formed at the second position.

  In the present invention, the hydraulic actuator may change a position of a working device provided in the machine body.

  In a work vehicle, the position of a work device provided in the machine body may be changed by driving a hydraulic actuator. Taking a combine harvester as an example of a working device, for example, changing the position of a tank for storing a harvested product and adjusting the height of a harvesting section are rarely performed when a harvesting operation is performed. Therefore, if the position of the working device is not changed by the hydraulic actuator, the hydraulic oil from the hydraulic pump can be continuously supplied to the hydraulic motor, and sufficient cooling air can be supplied to the radiator.

The present invention includes a rotation control valve that controls rotation of the hydraulic motor with respect to a first flow path to which hydraulic oil is supplied when the switching valve is set to the first position,
When the switching valve is set to the second position, an actuator control valve is provided for controlling the hydraulic actuator with respect to the second flow path to which hydraulic oil is supplied.

  According to this, in a state in which the switching valve is set to the first position, the rotation of the hydraulic motor is controlled by the control of the rotation control valve so that the cooling fan can be switched between forward rotation and reverse rotation. In the state where the switching valve is set to the second position, the hydraulic actuator can be controlled by controlling the actuator control valve.

1 is an overall side view of a corn harvester. It is a top view which shows arrangement | positioning of the hydraulic actuator of a corn harvester. It is a rear view which shows arrangement | positioning of a crop tank and a dump cylinder. It is a top view which shows an engine, a radiator, and a cooling fan. It is a longitudinal section showing an engine, a radiator, and a cooling fan. It is a perspective view which shows a radiator frame and a cooling fan. It is a hydraulic circuit diagram which shows a hydraulic motor and a hydraulic actuator.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
FIG. 1 shows a wheel-running corn harvester as an example of a work vehicle. The corn harvester has a traveling machine body F (an example of a working device) that travels with a pair of left and right front wheels 1 and a pair of left and right rear wheels 2, and includes a cabin 3 at a front position of the traveling machine body F. ing.

  As shown in the figure, the traveling machine body F performs the harvesting operation while traveling in the forward direction X. In the traveling machine body F, the end portion in the forward direction X is the front end. Further, in the traveling machine body F, the end in the direction opposite to the front direction X is the rear end. Further, the worker's right side is the right side of the traveling machine body F and the worker's left side is the left side of the traveling machine body F in a posture in which the worker is directed in the forward direction X.

  In the present invention, the working vehicle can be applied to a corn harvester that does not include a skinning device 15 described later, and can be applied to all working vehicles such as a wheel-type combine.

  A harvesting section A is provided at the front end of the traveling machine body F so as to be movable up and down, and the harvested product (corn in a state of being wrapped in foliage) harvested by the harvesting section A is transported upward and rearward from the front end of the traveling machine body F to the center. The transport device 5 is provided. The transport device 5 is provided with a blower 6 that blows off some of the leaves and stems mixed in the transported crop. At the central position of the traveling machine body F, a crop processing unit B that removes foliage from the crop supplied by the transport device 5 and a crop tank that stores corn from which the foliage has been removed by the crop processing unit B are stored. 7 (an example of a working device). Further, a residue processing device C (an example of a working device) is provided below the traveling machine body F and between the front wheel 1 and the rear wheel 2.

  The traveling machine body F includes a pair of left and right machine body frames 8 extending in the front-rear direction and a cabin frame 9 at the front position. The engine E is supported at a central position in the front-rear direction of the body frame 8, and a traveling transmission case 11 that drives the front wheels 1 is provided at a front position of the body frame 8. The rear wheel 2 is configured to be freely steerable. Further, the traveling machine body F includes a transmission system that transmits the driving force from the engine E to the traveling transmission case 11 or the harvesting part A, the harvested part processing part B, and the like.

  The cabin frame 9 is disposed at a position higher than the body frame 8 and supports the cabin 3. The cabin 3 has a general configuration including a windshield, left and right doors, and a roof, and includes a driver seat in which a work vehicle is seated. In the vicinity of the driver's seat, a steering hole, levers for controlling traveling of the traveling machine body, or levers for controlling work are arranged.

  The harvesting part A is provided with a plurality of dividers 12 at the tip position, and is provided with a plurality of conveying mechanisms 13 for conveying the harvested product while separating the harvest from the cereal grains introduced at the middle positions of these dividers 12. An auger 14 that rotates about an axial core in a lateral orientation is provided to transfer the harvested product to a central position in the left-right direction. The transport device 5 has a belt conveyor-shaped transport structure inside a duct-shaped case, and supplies the harvested product from the auger 14 to the harvested product processing section B.

  The harvest processing unit B is arranged in a positional relationship in which the peeling device 15, the swing sorting device 16, and the collection container 17 are vertically stacked. In the harvest processing unit B, the skinning device 15 removes the foliage from the harvest supplied from the transport device 5 and feeds the corn from which the foliage has been removed to the harvest tank 7. In the harvested product processing section B, the seed leaves separated by the skinning device 15 and a part of the seed grains separated from the corn are subjected to rocking and sorting by the rocking and sorting device 16, the leaf leaves are discharged out of the machine body, It is recovered in the recovery container 17.

  The residue processing apparatus C includes a plurality of crushing blades 18A with respect to the processing shaft 18 in the lateral orientation, and has a configuration in which these are accommodated in a processing case 19 that opens downward. With this configuration, the crushing blade 18 </ b> A shreds and crushes the residue of the farm scene and diffuses it into the soil by the drive rotation of the processing shaft 18.

[Hydraulic equipment]
As shown in FIGS. 1 and 2, the harvesting portion A is supported so as to be swingable around a support shaft 61 whose rear end portion is in a posture along the lateral direction of the traveling aircraft body F with respect to the front end of the traveling aircraft body F. Yes. Between the front part of the traveling transmission case 11 and the harvesting part A, a pair of left and right lift cylinders 62 (an example of a hydraulic actuator) that adjust the height of the harvesting part A to ground by swinging around the support shaft 61 are provided. I have.

  Each lift cylinder 62 has a bottom side connected to a pipe-like frame, and a tip of a piston rod connected to the harvesting part A. As a result, the front end position of the harvesting part A is lowered by the contraction operation of the lift cylinder 62, and the front end position of the harvesting part A is raised by the extension operation of the lift cylinder 62 so that the harvesting height in the harvesting part A can be adjusted. .

  As shown in FIGS. 2 and 3, the harvest tank 7 is centered on a dump shaft 65 in a posture along the longitudinal direction of the machine body with respect to the upper end portion of the support column 64 arranged at the front and rear positions of the harvest tank 7. While being supported in a swingable manner, it is configured to be movable by a dump cylinder 66 (an example of a hydraulic actuator). The dump cylinder 66 has a bottom side connected to the support column and a tip of the piston rod connected to the harvest tank 7.

  As a result, when the dump cylinder 66 is in the contracted state, the opening of the harvest tank 7 is maintained in a harvesting posture toward the upper side, and the harvest tank 7 swings around the dump shaft 65 by extending the dump cylinder 66. This makes the opening of the crop tank 7 face in the horizontal direction and allows the harvest to be discharged.

  As shown in FIGS. 1 and 2, the residue processing device C is supported so as to be swingable about a swinging shaft 68 in a posture along the lateral direction of the traveling machine body F, and a lifting cylinder 69 (an example of a hydraulic actuator) It is supported in a suspended state by a chain 70 connected to the tip of the piston rod.

  Thus, by retracting the elevating cylinder 69, the residue processing device C can be raised and held away from the ground. Further, when the elevating cylinder 69 is extended, the crushing blade 18A of the residue processing device C is brought into contact with the ground by swinging around the swing shaft 68, and the residue can be processed. In addition, since the residue processing apparatus C is suspended via the chain 70, the upward displacement can be easily performed even when the protrusion on the ground is ridden.

[Radiator]
As shown in FIGS. 4 to 6, the radiator 31 and the intake case 32 are supported with respect to the radiator frame 40 provided on the right side of the body frame 8. The radiator 31 is disposed outside the body of the engine E, and the vertical center position thereof is set higher than the vertical center position of the engine E. In addition, a dust-proof net 33 is provided on the outer surface of the intake case 32, a cooling fan 34 is disposed on the back side of the radiator 31, and a fan shroud 35 is provided on the back side of the radiator 31 at a position surrounding the cooling fan 34. The radiator 31 is connected to the engine E via a pair of radiator hoses 36 so that the cooling water from the engine E is cooled and returned to the engine E.

  Although not shown in the drawing, an oil cooler that radiates hydraulic oil and a capacitor that radiates refrigerant are accommodated in the intake case 32.

  The radiator frame 40 includes an auxiliary frame 41 projecting outward from the machine body frame 8, a pair of front and rear columnar frames 42 erected on the upper surface of the auxiliary frame 41, and upper ends of the pair of columnar frames 42. And an upper connecting frame 43 in a front-and-back orientation that is connected to the front and rear. The radiator frame 40 also includes a pair of auxiliary upper frames 44 that extend inward from the two locations of the middle position in the front-rear direction of the upper connecting frame 43 and the position on the front end side.

  Further, the radiator frame 40 includes an auxiliary support frame 45 on the inner side of the body with reference to a support frame 42 on the front side of the machine body. An auxiliary upper frame 44 on the front side of the machine body is connected to the upper end of the auxiliary support frame 45. Yes. The extending ends of the horizontal frame 45a extending rearward from the intermediate position of the auxiliary support frame 45 and the vertical frame 44a extending downward from the auxiliary upper frame 44 at the central position are connected to each other. A hydraulic motor M is supported on the connecting portion via a motor bracket 37, and a cooling fan 34 is connected to the output shaft of the hydraulic motor M.

[Hydraulic circuit]
In this corn harvester, lubricating oil stored inside the traveling transmission case 11 is used as hydraulic oil, and the traveling transmission case 11 is also used as a main tank for hydraulic oil. Further, a hydraulic oil tank 47, a control valve unit VU, and a battery having a capacity smaller than that of the main tank are disposed in the body frame 8 in the vicinity of the radiator frame 40.

  FIG. 7 shows a hydraulic circuit for supplying hydraulic oil of the hydraulic pump P to the lift cylinder 62, the dump cylinder 66, the lifting cylinder 69, and the hydraulic motor M. The hydraulic oil tank 47 is configured so that a constant amount of hydraulic oil is always stored, and the hydraulic oil flows between the hydraulic oil tank and the main tank (traveling transmission case 11). The lift cylinder 62 and the dump cylinder 66 are provided as a pair in the traveling machine body F, but are shown as a single one in the hydraulic circuit diagram.

  In the present invention, the hydraulic oil tank 47 may be disposed near the radiator frame 40 as the main tank.

  In addition, a flow path through which the hydraulic pump P sucks the hydraulic oil in the hydraulic oil tank 47, a flow path for supplying the hydraulic oil from the hydraulic pump P to the control valve unit VU, and the hydraulic oil from the control valve unit VU as the hydraulic oil A flow path for discharging to the tank 47 is formed. Further, a pair of motor flow paths 51 are formed between the control valve unit VU and the hydraulic pump P. These flow paths are constituted by dedicated pipes.

   The control valve unit VU includes a switching valve 72. The switching valve 72 has a first position 72a for supplying the hydraulic oil from the hydraulic pump P to the hydraulic motor M, and the hydraulic oil from the hydraulic pump P to the hydraulic actuators (the lift cylinder 62, the dump cylinder 66, and the lift cylinder 69). A spool that can be switched to the second position 72b to be supplied is provided.

  That is, the control valve unit VU forms a first flow path Q1 for supplying hydraulic oil from the switching valve 72 to the hydraulic motor M, and a second flow path Q2 for supplying hydraulic oil from the switching valve 72 to the hydraulic actuator. Yes. A rotation control valve 73 that sets the rotation direction of the hydraulic pump P is provided in the first flow path Q1. A lift control valve 74 (an example of an actuator control valve) for controlling the lift cylinder 62 and a dump control valve 75 (an example of an actuator control valve) for controlling the dump cylinder 66 at positions where hydraulic oil is supplied from the second flow path Q2. ) And a lift control valve 76 (an example of an actuator control valve) that controls the lift cylinder 69.

  The switching valve 72 is configured as an electromagnetic valve having a spool that can be switched between a first position 72a and a second position 72b. When power is not supplied to the electromagnetic solenoid, the spool is held at the first position 72a. The rotation control valve 73 is configured as an electromagnetic valve having a spool that can be switched between a forward rotation position and a reverse rotation position, and when power is not supplied to the electromagnetic solenoid, the spool is held in the forward rotation position.

  The actuator control valves (lift control valve 74, dump control valve 75, and lift control valve 76) are configured as electromagnetic valves having a spool that can be switched between a neutral position, an extended position, and a contracted position. These actuator control valves are held in a neutral position that shuts off the supply of hydraulic oil when power is not supplied to the electromagnetic solenoid, and are set to the extended position so that the hydraulic oil is supplied to the corresponding cylinder for extension operation. By setting the contraction position, the hydraulic oil is discharged from the corresponding cylinder to perform the contraction operation.

  Note that a check valve or the like is provided in a flow path to which hydraulic oil is supplied from the lift control valve 74, the dump control valve 75, and the lift control valve 76.

  In particular, the switching valve 72 includes a pair of ports connected to the pair of flow paths of the first flow path Q1. When the switching valve 72 is set to the first position 72a, the switching valve 72 supplies hydraulic oil to the first flow path Q1 through a pair of ports. However, the pressure of the hydraulic oil from the hydraulic pump P is changed. The state of acting on the second flow path Q2 is also maintained.

  When the switching valve 72 is set to the second position 72b, the hydraulic oil from the hydraulic pump P is shut off and the hydraulic oil is supplied only to the second flow path Q2. The switching valve 72 forms a circulation channel 72c that allows a pair of ports to communicate with each other at the second position 72b. The circulation passage 72c forms a rotation allowing portion that allows the hydraulic oil to circulate in the pair of motor passages 51 of the hydraulic motor M.

  Note that the switching valve 72 is not limited to the configuration shown in FIG. 7. For example, when the switching valve 72 is set to the first position 72 a, the supply of hydraulic oil to the second flow path Q <b> 2 is shut off, and the second position 72 b is set. When set, the supply of hydraulic oil to the first flow path may be shut off, and the hydraulic oil may be supplied to the second flow path Q2.

  The control valve unit VU performs a control for driving the cooling fan 34 in the forward rotation direction for sucking the cooling air by a control signal from the control device 48, for example, for 3 minutes, and the cooling fan 34 in the reverse rotation direction for discharging the cooling air. Is controlled for 10 seconds, and the hydraulic oil is controlled to repeat these controls. In particular, when the spool of the rotation control valve 73 is operated to switch the rotation direction of the hydraulic motor M, the hydraulic oil is hardly supplied to the hydraulic motor M between the forward rotation position and the reverse rotation position. Will appear.

  When the work clutch that transmits the driving force of the engine E to the harvesting part A and the harvested product processing part B is in the disengaged state in order to perform the harvesting work, the cooling fan 34 is driven forward and the work clutch 24 is The control mode is set so that the cooling fan 34 is switched between the normal rotation and the reverse rotation only when the operation is performed. The switching between the normal rotation and the reverse rotation is performed regardless of the state of the work clutch 24. You can go. Further, switching between the normal rotation and the reverse rotation of the cooling fan 34 is performed when a work clutch for transmitting the driving force of the engine E to the harvesting section A and the harvested product processing section B is engaged and operated in order to perform harvesting work. However, it may be performed regardless of the state of the working clutch.

  The forward rotation time and the reverse rotation time of the cooling fan 34 are not set to fixed values. For example, the normal rotation time and the reverse rotation time can be automatically changed according to the work load. It may be configured to be changed by a typical operation.

  When the rotation control valve 73 passes through an intermediate position between the first position 72a and the second position 72b, the hydraulic oil M is not supplied or discharged with hydraulic fluid. In this state, a large braking force is applied to the hydraulic motor M, so that smooth deceleration is not performed, leading to inconvenience that causes vibration and impact. In particular, when the rotation direction of the cooling fan 34 is switched, the hydraulic motor M tends to rotate with inertia, so that surge pressure is applied to one of the pair of motor flow paths 51 through which hydraulic oil is supplied to and discharged from the hydraulic motor M. Occurred (excessive pressure is applied), and negative pressure is generated on the other side, leading to leakage of hydraulic oil from the flow path or damage to the flow path. In order to eliminate this inconvenience, the control valve unit VU has a pressure difference that suppresses a surge pressure generated in one of the pair of motor flow paths 51 and suppresses a negative pressure generated in one of the pair of motor flow paths 51. A suppression circuit is provided.

  The pressure difference suppression circuit includes a relief channel and a suction channel. The relief flow path includes a first connection flow path 52 connected to the pair of motor flow paths 51, a relief check valve 53 on the downstream side of the first connection flow path 52, and a pair of relief check valves 53. A merging channel 54 for merging the hydraulic oil and a relief valve 55 connected to the merging channel 54 are provided. In this relief flow path, only when the pressure of the pair of motor flow paths 51 rises, the hydraulic oil in the motor flow path 51 is discharged to the relief valve 55, and a check for relief is performed so as to prevent the flow of hydraulic oil in the reverse direction. The direction of the valve 53 is set. Further, the hydraulic oil from the relief valve 55 is discharged from the tank passage 56 to the hydraulic oil tank 47.

  The suction channel includes a tank channel 56 communicating with the hydraulic oil tank 47 (also used as a hydraulic oil discharge system from the relief valve 55), a branch channel 57 branching from the tank channel 56, and a pair of A suction check valve 59 is provided at a position connecting the second connection channel 58 connected to the motor channel 51 and the branch channel 57 and the second connection channel 58. In this suction flow path, the direction of the suction check valve 59 is set so that the hydraulic oil in the hydraulic oil tank 47 can be sucked into the motor flow path 51 only when the pressure of the motor flow path 51 is reduced. Yes.

[Control form]
The corn harvester includes a control device 48 that controls the switching valve 72, the rotation control valve 73, the lift control valve 74, the dump control valve 75, and the lift control valve 76. The control device 48 includes a control circuit having a microprocessor, a DSP, and the like, and software. The control valve 72 and the rotation control valve 73 are operated by operating a lever inside the cabin 3 or operating a switch. The lift control valve 74, the dump control valve 75, and the lift control valve 76 are operated.

  When the hydraulic actuator (the lift cylinder 62, the dump cylinder 66, and the lift cylinder 69) is not driven, the control device 48 holds the switching valve 72 at the first position 72a and sets the rotation control valve 73 at the set interval. In this way, a state in which the hydraulic motor M is normally rotated and a state in which the hydraulic motor M is reversed are alternately generated. Specifically, as described above, the control for continuously rotating in the forward direction for the set time and then rotating in the reverse direction for a time shorter than the set time is repeatedly performed.

  When a manual operation for operating the hydraulic actuator is performed, the switching valve 72 is set to the second position 72b so that the supply of the hydraulic oil to the first flow path Q1 is interrupted. Operate the control valve of the hydraulic actuator. Accordingly, the operation is realized by supplying the hydraulic oil to the hydraulic actuator to be operated.

  In addition, hydraulic actuators (lift cylinder 62, dump cylinder 66, and lifting cylinder 69) of the corn harvester are often operated in a stopped state, and are hardly operated during the harvesting operation. The hydraulic oil is supplied to the one flow path Q1 and the cooling fan 34 is rotated to allow the radiator 31 to cool the cooling water.

  Thus, in the situation where hydraulic fluid is supplied to the first flow path Q1, when the position of the spool of the rotation control valve 73 is switched by the control signal from the control device 48, the pair of motor flow paths 51 are controlled. Since the amount of hydraulic oil supplied from the rotation control valve 73 is temporarily stopped, in this state, the hydraulic motor M continues to rotate with inertia, and the hydraulic motor M functions like a hydraulic pump. One surge pressure is generated in the motor flow path 51 and a negative pressure acts on the other, but since the pressure difference suppression circuit is provided, the generated surge pressure is suppressed and the negative pressure is also suppressed.

  Thereby, even when the control device 48 alternately performs the forward drive control and the reverse drive control of the hydraulic motor M via the rotation control valve 73 at the time of work, the rotation of the cooling fan 34 is suddenly stopped. Instead, the motor is smoothly decelerated and stopped in a state in which rotation due to inertia is allowed, and thereafter, the hydraulic motor M is reversely rotated to realize smooth rotation control of the cooling fan 34.

  Further, when the hydraulic actuator operates, the switching valve 72 is switched from the first position 72a to the second position 72b by a control signal from the control device 48. Although the supply of hydraulic oil to the first flow path Q1 is interrupted by this switching, the pair of motor flow paths 51 are in communication with each other through the circulation flow path 72c, so that the cooling fan 34 and the hydraulic motor M are subjected to inertia. The flow of hydraulic oil during rotation is enabled, cooling by the cooling fan 34 is continued, and overheating of the engine E is not caused.

  When the switching valve 72 is switched from the first position 72a to the second position 72b, the control device 48 does not control the rotation control valve 73 but maintains the position before the switching valve 72 is switched.

[Operation / Effect of Embodiment]
By providing the switching valve 72, the hydraulic motor M is driven by using the hydraulic pump P provided for supplying hydraulic oil to a plurality of hydraulic actuators (the lift cylinder 62, the dump cylinder 66, and the lift cylinder 69). The cooling fan 34 of the radiator 31 can be rotated. That is, it is not necessary to provide a dedicated hydraulic pump for supplying hydraulic oil to the hydraulic motor M, thereby realizing cost reduction.

  Since the hydraulic oil pressure from the hydraulic pump P is always applied to the second flow path Q2, for example, even when the spool is fixed to the first position 72a due to a failure of the switching valve 72, a plurality of hydraulic actuators are provided. By controlling the control valves to be controlled (lift control valve 74, dump control valve 75, and lift control valve 76), although the amount of oil is reduced, the corresponding hydraulic actuator can be operated.

  By providing the pressure difference suppression circuit, even when the rotation control valve 73 is controlled, a pair of hydraulic oil is completely stopped at the timing when the spool reaches the middle between the forward rotation position and the reverse rotation position. The pressure difference in the motor flow path 51 is suppressed to enable smooth deceleration, and no shock is generated and the flow path system is not damaged by an excessive pressure difference.

  Further, since the circulation flow path 72c is formed at the second position 72b of the switching valve 72, the hydraulic oil is not supplied to the hydraulic motor M as in the case where the spool is switched from the first position 72a to the second position 72b. Even in the situation, the circulation flow path 72c can circulate the hydraulic oil in the pair of motor flow paths 51. As a result, the cooling fan 34 is allowed to rotate due to inertia, so that some cooling air can be supplied to the radiator 31 and overheating of the engine E can be suppressed.

  The cooling fan 34 that supplies cooling air to the radiator 31 is rotated by the hydraulic motor M, and the rotation direction of the hydraulic motor M is switched by switching the supply / discharge direction of the hydraulic oil. Therefore, the rotation direction is switched using a clutch, a gear, or the like. The configuration is simplified compared to the one.

  INDUSTRIAL APPLICABILITY The present invention can be used for a working vehicle that supplies hydraulic oil to a hydraulic motor that drives a cooling fan and a hydraulic actuator that is provided in the airframe.

31 Radiator 33 Dust-proof net 34 Cooling fan 48 Control device 62 Hydraulic actuator (lift cylinder)
66 Hydraulic actuator (dump cylinder)
69 Hydraulic actuator (lifting cylinder)
72 Switching valve 72a 1st position 72b 2nd position 72c Rotation permission part and flow path (circulation flow path)
73 Rotation control valve 74 Actuator control valve (lift control valve)
75 Actuator control valve (Dump control valve)
76 Actuator control valve (lift control valve)
E Engine F Airframe (Travel Aircraft)
M Hydraulic motor P Hydraulic pump Q1 First flow path Q2 Second flow path

Claims (7)

A radiator that cools cooling water of the engine, a dust net disposed outside the fuselage from the radiator, a cooling fan that is disposed inside the fuselage and supplies cooling air to the radiator, and drives the cooling fan A hydraulic motor,
A work vehicle comprising a hydraulic pump that supplies hydraulic oil to a hydraulic actuator provided in the airframe, and a switching valve that selectively supplies hydraulic oil from the hydraulic pump to one of the hydraulic actuator and the hydraulic motor. .   The switching valve is configured to be switchable between a first position for supplying hydraulic oil from the hydraulic pump to the hydraulic motor and a second position for supplying hydraulic oil from the hydraulic pump to the hydraulic actuator. The work vehicle according to claim 1.   The work vehicle according to claim 2, further comprising a control device that sets the switching valve to the second position when the hydraulic actuator is driven and sets the switching valve to the first position when the hydraulic actuator is stopped.   4. The work vehicle according to claim 2, wherein when the switching valve is set to the second position, the switching valve includes a rotation allowing portion that allows rotation due to inertia of the hydraulic motor. 5.   The switching valve includes a pair of ports for discharging and receiving hydraulic oil to and from the hydraulic motor, and the rotation allowing portion allows the hydraulic oil to circulate between the pair of ports. The work vehicle of Claim 4 comprised by these.   The work vehicle according to any one of claims 1 to 5, wherein the hydraulic actuator changes a position of a work device provided in the machine body. A rotation control valve for controlling rotation of the hydraulic motor with respect to a first flow path to which hydraulic oil is supplied when the switching valve is set to the first position;
The actuator control valve which controls the said hydraulic actuator with respect to the 2nd flow path where hydraulic fluid is supplied when the said switching valve is set to the said 2nd position is provided. Work vehicle as described in.

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