Control method of work vehicle and work vehicle

Abstract

To provide a control method of a work vehicle and the work vehicle allowing operability to be easily improved.SOLUTION: A control method of a work vehicle 3 comprises: supplying working fluid to a first travel motor 431 in a travel part of the work vehicle 3 through a first supply passage 61; supplying the working fluid to a second travel motor 432 in the travel part to a second supply passage 62; and joining the fluid in the first supply passage 61 and the second supply passage 62 when a specific work part other than the travel part of the work vehicle 3 works during operation of the travel part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a work vehicle control method used in a work vehicle having a traveling part that operates using a working fluid, and the work vehicle. [Background technology]

[0002] As a related art, a work vehicle is known that is equipped with a hydraulic circuit and operates a traveling section (traveling device) using hydraulic oil as a working fluid (see, for example, Patent Document 1).In a work vehicle according to the related art, the traveling section is equipped with a pair of left and right crawlers, and the crawler on the left side of the machine body is driven by a first traveling motor (left traveling hydraulic motor), and the crawler on the right side of the machine body is driven by a second traveling motor (right traveling hydraulic motor), thereby moving the work vehicle forward and backward and turning.

[0003] A work vehicle according to the related art is equipped with two hydraulic pumps that supply hydraulic oil to a work hydraulic actuator and a pair of left and right traveling motors (a first traveling motor and a second traveling motor) via pilot-type directional control valves provided for each of the work hydraulic actuator and the pair of left and right traveling motors. When this work vehicle supplies working fluid to the work hydraulic actuator and the traveling motors simultaneously, the working fluid discharged from the two hydraulic pumps is merged at a merging valve. Furthermore, when working fluid is supplied to the traveling motors, this work vehicle reduces the pilot pressure applied to the directional control valve corresponding to the work hydraulic actuator. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-196437 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the related art described above, the operating speed of the working machine is slower when the machine is traveling than when the machine is stopped, which may cause some operators to feel uncomfortable with the operability of the working machine.

[0006] An object of the present invention is to provide a control method for a work vehicle and a work vehicle that can easily improve operability. [Means for solving the problem]

[0007] A control method for a work vehicle according to one embodiment of the present invention includes supplying a working fluid through a first supply passage to a first traveling motor in a running section of a work vehicle, supplying the working fluid through a second supply passage to a second traveling motor in the running section, and merging the first supply passage and the second supply passage when a specific operating section of the work vehicle other than the running section operates while the running section is operating.

[0008] A work vehicle according to one aspect of the present invention includes a first drive circuit, a second drive circuit, and a merging circuit. The first drive circuit supplies working fluid to a first travel motor in a travel section of the work vehicle through a first supply path. The second drive circuit supplies the working fluid to a second travel motor in the travel section through a second supply path. The merging circuit merges the first supply path and the second supply path when a specific operation section of the work vehicle other than the travel section operates while the travel section is in operation. Effect of the Invention

[0009] According to the present invention, it is possible to provide a control method for a work vehicle and a work vehicle that can easily improve operability. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view showing the overall configuration of a work vehicle according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a hydraulic circuit and the like of the work vehicle according to the first embodiment. [Diagram 3]FIG. 3 is a schematic diagram showing a hydraulic circuit during independent operation of the traveling section in the work vehicle according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a hydraulic circuit during combined operation of the traveling unit and the working unit in the work vehicle according to the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing a hydraulic circuit during operation of the turning section of the work vehicle according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing an example of the operation of the work vehicle according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0012] (Embodiment 1) [1] Overall structure As shown in Fig. 1, the work vehicle 3 according to this embodiment is equipped with a traveling section 31, a rotating section 32, and a working section 33 on a machine body 30. In addition, as shown in Fig. 1, the machine body 30 further includes a display device 2 and an operating device 35, etc.

[0013] In the present disclosure, the term "work vehicle" refers to a vehicle for various types of work, and examples thereof include work vehicles such as backhoes (including hydraulic excavators, mini excavators, etc.), wheel loaders, and carriers. The work vehicle 3 is equipped with a working unit 33 configured to be able to perform one or more tasks. The work vehicle 3 is not limited to construction machinery (construction equipment), and may be, for example, agricultural machinery (farm machinery) such as a rice transplanter, tractor, or combine harvester. In this embodiment, unless otherwise specified, an example will be described in which the work vehicle 3 is a riding type backhoe that is capable of performing tasks such as excavation work, ground leveling work, trench digging work, and loading work.

[0014] Also, in this embodiment, for convenience of explanation, the vertical direction in a state in which the work vehicle 3 is usable is defined as the up-down direction D1. Furthermore, in a non-rotating state of the rotating part 32, the front-rear direction D2 and the left-right direction D3 are defined based on the direction as seen by the user (operator) aboard the work vehicle 3 (the driving part 321 of the work vehicle 3). In other words, each direction used in this embodiment is a direction defined based on the body 30 of the work vehicle 3, and the direction in which the body 30 moves when the work vehicle 3 moves forward is "forward", and the direction in which the body 30 moves when the work vehicle 3 moves backward is "rear". Similarly, the direction in which the front end of the body 30 moves when the work vehicle 3 turns right is "rightward", and the direction in which the front end of the body 30 moves when the work vehicle 3 turns left is "leftward". However, these directions are not intended to limit the use direction of the work vehicle 3 (direction during use).

[0015] The work vehicle 3 is equipped with a power source. In the work vehicle 3, for example, a hydraulic pump 41 (see FIG. 2) is driven by the power source, and hydraulic oil is supplied from the hydraulic pump 41 to hydraulic actuators (including the travel motor 43, the swing motor 441, the hydraulic cylinder 442, etc.) of each part of the machine body 30, thereby driving the machine body 30. "Hydraulic oil" is an example of a working fluid.

[0016] The power source is a device that converts energy such as heat of combustion or steam, or electricity, into mechanical power (power) and supplies power (hydraulic oil) to each part of the machine body 30 of the work vehicle 3 to drive each part of the machine body 30. In this embodiment, as an example, the power source is a diesel engine that is driven by supplying diesel fuel from a fuel tank. The power source of the work vehicle 3 is not limited to a diesel engine, and may be, for example, an internal combustion engine (engine) other than a diesel engine, an electric motor (electric motor), or a hybrid power source including an internal combustion engine and an electric motor.

[0017] Such a work vehicle 3 is controlled, for example, by a user (operator) riding in the driver's section 321 of the machine body 30, operating an operating lever or the like of the operating device 35. In other words, the power generated by the prime mover 40 is distributed to each part of the machine body 30 according to the operation of the operator, and the work vehicle 3 operates according to the operation of the operator.

[0018] In this embodiment, since it is assumed that the work vehicle 3 is a riding type backhoe as described above, the working unit 33 is driven according to the operation of a user (operator) riding in the driving unit 321 to perform work such as excavation work. The driving unit 321 on which the user rides is provided in the rotating unit 32.

[0019] The traveling unit 31 has a traveling function and is configured to be able to travel (including turn) on the ground. The traveling unit 31 has, for example, a pair of left and right crawlers 311 and a blade 312. The traveling unit 31 further has a traveling motor 43 (hydraulic actuator) for driving the crawlers 311, and the like.

[0020] The traveling unit 31 includes a pair of crawlers (tracks) 311 aligned in the left-right direction D3. The pair of crawlers 311 are arranged at a fixed interval in the left-right direction D3. In other words, the traveling unit 31 is a crawler-type (endless track-type) traveling device that causes the work vehicle 3 to travel by driving the endless belt-like crawlers 311 with a traveling motor 43, which is a hydraulic motor.

[0021] Here, at least two travel motors 43 are provided corresponding to the pair of crawlers 311. A first travel motor 431 (see FIG. 1) on the right side that drives the right crawler 311 and a second travel motor 432 on the left side that drives the left crawler 311 can drive the crawlers 311 individually.

[0022] Here, the pair of crawlers 311 are driven by power from a power source in a state where independent speed changes are possible by a hydrostatic continuously variable transmission. Therefore, the machine body 30 is in a forward state moving straight forward in the forward direction when the pair of crawlers 311 are driven at a constant speed in the forward direction, and in a reverse state moving straight backward in the reverse direction when the pair of crawlers 311 are driven at a constant speed in the reverse direction. In addition, the machine body 30 is in a forward turning state turning while moving forward when the pair of crawlers 311 are driven at a non-uniform speed in the forward direction, and in a reverse turning state turning while moving backward when the pair of crawlers 311 are driven at a non-uniform speed in the reverse direction.

[0023] The machine body 30 is in a pivot turning state when one of the pair of crawlers 311 is stopped while the other is driven, and in a spin turning state when the pair of crawlers 311 are driven at a constant speed in the forward and reverse directions. The machine body 30 is in a travel stop state when the pair of crawlers 311 are stopped.

[0024] The swivel unit 32 is located above the travel unit 31, and is configured to be swivelable around a rotation axis along the vertical direction relative to the travel unit 31. The swivel unit 32 has a swivel motor 441 (hydraulic actuator) formed by a hydraulic motor, and the like. In addition to the driving unit 321, the swivel unit 32 is equipped with a power source, a hydraulic pump 41, and the like. Furthermore, a boom bracket 322 to which the working unit 33 is attached is provided at the front end of the swivel unit 32.

[0025] The working unit 33 is configured to be able to perform work including lifting work. The working unit 33 is supported by a boom bracket 322 of the swivel unit 32 and performs work. The working unit 33 has a bucket 331, a boom 332, an arm 333, and the like. The working unit 33 further has hydraulic actuators (including a hydraulic cylinder 442, etc.) for driving each unit.

[0026] The bucket 331 is a type of attachment (working tool) that is attached to the machine body 30 of the work vehicle 3, and is any tool selected from multiple types of attachments depending on the content of the work. As an example, the bucket 331 is removably attached to the machine body 30, and is replaced depending on the content of the work. In addition to the bucket 331, attachments for the work vehicle 3 include various tools such as a breaker, an auger, a crusher, a fork, a fork claw, a steel frame cutter, an asphalt cutter, a grass cutter, a ripper, a mulcher, a tilt rotator, and a tamper. The working unit 33 performs work by driving the bucket 331 with power from a drive device.

[0027] The boom 332 is rotatably supported by the boom bracket 322 of the swivel section 32. Specifically, the boom 332 is supported by the boom bracket 322 so as to be rotatable about a rotation axis along the horizontal direction. The boom 332 has a shape that extends upward from a base end supported by the boom bracket 322. The arm 333 is connected to the tip of the boom 332. The arm 333 is supported relative to the boom 332 so as to be rotatable about a rotation axis along the horizontal direction. A bucket 331 is attached to the tip of the arm 333.

[0028] The working unit 33 operates by receiving power from a power source. Specifically, the power source drives a hydraulic pump 41, and hydraulic oil is supplied from the hydraulic pump 41 to hydraulic actuators (hydraulic cylinder 442, etc.) of the working unit 33, thereby operating each part of the working unit 33 (the bucket 331, the boom 332, and the arm 333).

[0029] Particularly in this embodiment, the working unit 33 has a multi-joint structure in which the boom 332 and the arm 333 are configured to be rotatable individually. In other words, by each of the boom 332 and the arm 333 rotating about a rotation axis along the horizontal direction, the multi-joint working unit 33 including the boom 332 and the arm 333 can, for example, be extended or folded as a whole.

[0030] Similarly to the working unit 33, each of the traveling unit 31 and the swivel unit 32 receives power from a power source and operates. That is, the traveling motor 43 of the traveling unit 31 and the swivel motor 441 of the swivel unit 32 are supplied with hydraulic oil (working fluid) from the hydraulic pump 41, thereby causing the traveling unit 31 and the swivel unit 32 to operate.

[0031] The display device 2 is disposed in the driving section 321 of the machine body 30, and is a user interface for receiving operation inputs by a user (operator) and outputting various information to the user. The display device 2 receives various operations by the user, for example, by outputting an electrical signal in response to the user's operation. This allows the user (operator) to visually check the display screen displayed on the display device 2, and also allows the user (operator) to operate the display device 2 as necessary.

[0032] The operation device 35 is disposed in the driving section 321 of the machine body 30, and is a user interface for receiving operation input from a user (operator). The operation device 35 includes, for example, an operation lever, and controls a remote control valve 45 (see FIG. 2) according to the amount of operation of the operation lever. This allows the operator to operate the remote control valve 45 by operating the operation device 35, to specify the direction and flow rate of hydraulic oil from the hydraulic pump 41, and to operate the work vehicle 3.

[0033] In addition to the above-mentioned configuration, the machine body 30 further includes a control device, a sound output unit, a communication terminal, a cut-off lever, a fuel tank, a battery, a camera that captures images of the periphery of the machine body 30, and various sensors for detecting objects to be detected in the monitoring area around the work vehicle 3. Furthermore, the machine body 30 includes sensors (including cameras) for monitoring the operating state of the machine body 30, such as a cooling water temperature sensor, a hydraulic oil temperature sensor, a tachometer that measures the engine RPMs, and an hour meter that measures operating time.

[0034] [2] Hydraulic circuit configuration Next, the configuration of the hydraulic circuit of the work vehicle 3 according to this embodiment will be described with reference to Fig. 2. In Fig. 2, solid lines indicate high-pressure oil passages (for hydraulic oil), and dotted lines indicate low-pressure oil passages (for pilot oil).

[0035] 2, the work vehicle 3 is equipped with a pilot pump 42, a remote control valve 45, a merging valve 46, a first auxiliary valve 471, a second auxiliary valve 472, a first relief valve 481, and a second relief valve 482, in addition to the hydraulic pump 41, the traveling motor 43, the swing motor 441, and the hydraulic cylinder 442. Here, the traveling motor 43 includes the first traveling motor 431 for driving the right crawler 311, and the second traveling motor 432 for driving the left crawler 311, as described above.

[0036] Furthermore, the work vehicle 3 is equipped with directional control valves (control valves) 51-54 corresponding to the first traveling motor 431, the second traveling motor 432, the swing motor 441, and the hydraulic cylinder 442, which are hydraulic actuators. The directional control valves 51-54 are pilot-type directional control valves that can switch the direction and flow rate of hydraulic oil from the hydraulic pump 41, and are driven by the supply of pilot oil, which serves as an input command, from the pilot pump 42.

[0037] Here, for example, a remote control valve 45 is provided in a supply path of pilot oil to the (third) directional control valve 53 corresponding to the swing motor 441 of the swing part 32. The remote control valve 45 outputs a swing operation command for the swing part 32 in response to the operation of the operating device 35 (operation lever), and controls the direction and flow rate of the hydraulic oil supplied to the swing motor 441, thereby controlling the operating state of the swing part 32. The swing operation command instructs the swing operation (left swing, right swing, etc.) of the swing part 32.

[0038] Similarly, a remote control valve that outputs a travel operation command for the traveling unit 31 in response to operation of an operating device is provided in a pilot oil supply path to the (first) directional control valve 51 corresponding to the first traveling motor 431 of the traveling unit 31 and the (second) directional control valve 52 corresponding to the second traveling motor 432. The travel operation command instructs the traveling operation (forward or backward, etc.) of the traveling unit 31. Furthermore, a remote control valve that outputs a work operation command for the working unit 33 in response to operation of an operating device is provided in a pilot oil supply path to the (fourth) directional control valve 54 corresponding to the hydraulic cylinder 442 of the working unit 33. The work operation command instructs the deployment operation, retraction operation, etc. of the working unit 33.

[0039] In this embodiment, the hydraulic pump 41 includes a first pump 411 and a second pump 412. The first pump 411 supplies a working fluid (hydraulic oil) to the first traveling motor 431 and the swing motor 441 through a first supply path 61. The second pump 412 supplies a working fluid (hydraulic oil) to the second traveling motor 432 and the hydraulic cylinder 442 through a second supply path 62.

[0040] That is, the first supply path 61 is a path (oil path) that supplies hydraulic oil from the first pump 411 to the first traveling motor 431 and the swing motor 441, and is provided downstream of the first relief valve 481. The second supply path 62 is a path (oil path) that supplies hydraulic oil from the second pump 412 to the second traveling motor 432 and the hydraulic cylinder 442, and is provided downstream of the second relief valve 482.

[0041] The junction valve 46 is inserted between the first supply path 61 and the second supply path 62. The junction valve 46 is switchable between a blocked state and a connected state, and in the blocked state, separates (isolates) the first supply path 61 and the second supply path 62, and in the connected state, joins (communicates) the first supply path 61 and the second supply path 62.

[0042] The junction valve 46 switches between a blocked state and a connected state in response to a first pilot signal Si1 input through a first control path 71, which is a path (oil passage) for pilot oil. Specifically, when the first pilot signal (pilot pressure) Si1 input to the junction valve 46 is increased by pilot oil supplied to the junction valve 46 from the pilot pump 42 through the first control path 71, the junction valve 46 is in the connected state. On the other hand, when the first pilot signal (pilot pressure) Si1 is decreased (reduced in pressure), the junction valve 46 is in the blocked state.

[0043] The first auxiliary valve 471 and the second auxiliary valve 472 are provided on the first control path 71. In the present embodiment, as an example, the first auxiliary valve 471 and the second auxiliary valve 472 are inserted in series on the first control path 71, which is an input path for the first pilot signal Si1, so that the first auxiliary valve 471 is on the upstream side and the second auxiliary valve 472 is on the downstream side (the junction valve 46 side).

[0044] The first auxiliary valve 471 opens and closes in response to a second pilot signal Si2 input through a second control path 72, which is a path (oil passage) for pilot oil. Specifically, when the second pilot signal (pilot pressure) Si2 input to the first auxiliary valve 471 is boosted by pilot oil supplied from the pilot pump 42 to the first auxiliary valve 471 through the second control path 72, the first auxiliary valve 471 opens and passes the first pilot signal Si1. On the other hand, when the second pilot signal (pilot pressure) Si2 is lowered (reduced in pressure), the first auxiliary valve 471 closes and blocks the first pilot signal Si1.

[0045] The second auxiliary valve 472 opens and closes in response to a third pilot signal Si3 input through a third control path 73, which is a path (oil passage) for pilot oil. Specifically, when the third pilot signal (pilot pressure) Si3 input to the second auxiliary valve 472 is increased by pilot oil supplied from the pilot pump 42 to the second auxiliary valve 472 through the third control path 73, the second auxiliary valve 472 is closed and blocks the first pilot signal Si1. On the other hand, when the third pilot signal (pilot pressure) Si3 is decreased (reduced in pressure), the second auxiliary valve 472 is opened and passes the first pilot signal Si1.

[0046] In short, the junction valve 46 is in a communicating state to merge the first supply path 61 and the second supply path 62 only when the first pilot signal Si1 is boosted, the second pilot signal Si2 input to the first auxiliary valve 471 is boosted, and the third pilot signal Si3 input to the second auxiliary valve 472 is lowered (reduced in pressure). For example, when the second pilot signal Si2 is lowered (reduced in pressure) and when the third pilot signal Si3 is boosted, the junction valve 46 is in a blocked state to separate the first supply path 61 and the second supply path 62.

[0047] Here, the first control path 71 is a path provided by branching off from the travel detection path 74 in the supply path of pilot oil from the pilot pump 42. The travel detection path 74 is a path for detecting the operating state of the traveling unit 31. Specifically, the travel detection path 74 is a path (oil path) that connects from the pilot pump 42 to the drain through the directional control valves 51, 52 corresponding to the traveling motors 43 (the first traveling motor 431 and the second traveling motor 432). When at least one of the first traveling motor 431 and the second traveling motor 432 operates, the spools of the directional control valves 51, 52 move to block the travel detection path 74, so that the pilot oil flowing through the travel detection path 74 is guided to the first control path 71, and the first pilot signal Si1 is boosted.

[0048] The second control path 72 is a path that branches off from the operation detection path 75 in the supply path of pilot oil from the pilot pump 42. The operation detection path 75 is a path for detecting the operating state of the working unit 33. Specifically, the operation detection path 75 is a path (oil path) that connects from the pilot pump 42 to the drain through the directional control valve 54 corresponding to the hydraulic cylinder 442. When the hydraulic cylinder 442 operates, the spool of the directional control valve 54 moves to block the operation detection path 75, so that the pilot oil flowing through the operation detection path 75 is guided to the second control path 72, and the second pilot signal Si2 is boosted.

[0049] The third control path 73 is a path that branches off from the swing detection path 76 in the supply path of pilot oil from the pilot pump 42. The swing detection path 76 is a path for detecting the operating state of the swing unit 32. Specifically, the swing detection path 76 is a path (oil path) that connects to the remote control valve 45 for operating the swing motor 441, and the third control path 73 is connected to the swing detection path 76 via a shuttle valve 49. When an operation is performed with the operating device 35 to operate the swing unit 32, the pilot oil flowing through the swing detection path 76 is guided to the third control path 73 via the shuttle valve 49, and the third pilot signal Si3 is boosted.

[0050] In short, the work vehicle 3 according to this embodiment includes a first drive circuit 301, a second drive circuit 302, and a junction circuit 303, as shown in Fig. 2. The first drive circuit 301 supplies working fluid to a first travel motor 431 in the travel section 31 of the work vehicle 3 through a first supply path 61. The second drive circuit 302 supplies working fluid to a second travel motor 432 in the travel section 31 through a second supply path 62. The junction circuit 303 merges the first supply path 61 and the second supply path 62 when a specific operation section of the work vehicle 3 other than the travel section 31 is operating while the travel section 31 is operating.

[0051] Here, the first drive circuit 301 includes a first pump 411, a first supply passage 61, and directional control valves 51 and 53, etc. The second drive circuit 302 includes a second pump 412, a second supply passage 62, and directional control valves 52 and 54, etc. The merging circuit 303 includes a merging valve 46, a first auxiliary valve 471, and a second auxiliary valve 472, etc.

[0052] [3] Method for controlling a work vehicle Next, a control method for the work vehicle 3 according to this embodiment will be described with reference to Figures 3 to 6. In Figures 3 to 5, similar to Figure 2, solid lines indicate high-pressure oil passages (for hydraulic oil) and dotted lines indicate low-pressure oil passages (for pilot oil). Furthermore, in Figures 3 to 5, boosted pilot signals (pilot pressures) are indicated by thick arrows.

[0053] The control method for the work vehicle 3 according to this embodiment includes supplying working fluid to a first traveling motor 431 in the traveling section 31 of the work vehicle 3 through a first supply path 61, and supplying working fluid to a second traveling motor 432 in the traveling section 31 through a second supply path 62. Furthermore, the control method for the work vehicle 3 includes merging the first supply path 61 and the second supply path 62 when a specific operating section of the work vehicle 3 other than the traveling section 31 is operated while the traveling section 31 is in operation.

[0054] Here, the specific operating unit may be any specific operating unit other than the traveling unit 31 of the work vehicle 3, such as the turning unit 32, the working unit 33, or other operating units, or a combination of these. In this embodiment, the working unit 33 is an example of a "specific operating unit." Also, in this embodiment, the hydraulic oil supplied from the hydraulic pump 41 (the first pump 411 and the second pump 412) is an example of a hydraulic fluid.

[0055] That is, according to the control method for the work vehicle 3 according to this embodiment, it is possible to merge the first supply path 61 and the second supply path 62 during "combined operation" in which a specific operation unit (the working unit 33, as one example) other than the traveling unit 31 of the work vehicle 3 operates while the traveling unit 31 is in operation. As a result, during "combined operation" in which both the traveling unit 31 and the specific operation unit operate, the working fluid of the first supply path 61 and the second supply path 62 can be merged to suppress a reduction in pressure of the working fluid to the traveling unit 31 (the first traveling motor 431 and the second traveling motor 432) due to the operation of the specific operation unit.

[0056] As a result, it is possible to suppress the occurrence of problems such as running shock (shock due to sudden speed changes) or cornering in the running unit 31 without reducing the operating speed of the specific operating unit while running compared to when the vehicle is stopped. Therefore, it is possible to provide a control method for a work vehicle 3 and a work vehicle 3 that can easily improve operability.

[0057] Furthermore, in the control method for the work vehicle 3 according to this embodiment, when the rotating unit 32 of the work vehicle 3 is operated while the traveling unit 31 is in operation, the confluence of the first supply path 61 and the second supply path 62 is released. In other words, the first supply path 61 and the second supply path 62 are not always joined during "combined operation" in which both the traveling unit 31 and the specific operation unit (the working unit 33 as an example) are in operation, but when the rotating unit 32 is in operation, the confluence of the first supply path 61 and the second supply path 62 is exceptionally released even during combined operation. This makes it possible to suppress traveling shock caused by an increase or decrease in the flow rate due to horsepower control accompanying the confluence of the first supply path 61 and the second supply path 62 when the rotating unit 32 is in operation.

[0058] Furthermore, the control method for the work vehicle 3 according to this embodiment cancels the confluence of the first supply path 61 and the second supply path 62 while the traveling part 31 is operating independently. In other words, during a period when the specific operation part (the working part 33 as one example) is not operating and only the traveling part 31 is operating (during independent operation), the confluence of the first supply path 61 and the second supply path 62 is canceled. This makes it possible to ensure traveling and steering performance while the traveling part 31 is operating independently.

[0059] Specifically, as shown in Figures 3 and 4, the first supply path 61 is a path that supplies working fluid from the first pump 411 to the first traveling motor 431 and the swing motor 441 in the swing section 32 of the work vehicle 3. The second supply path 62 is a path that supplies working fluid from the second pump 412 to the second traveling motor 432. The working fluid is supplied to the actuator of the specific operation section from at least one of the first supply path 61 and the second supply path 62. In the control method for the work vehicle 3 according to this embodiment, the first supply path 61 and the second supply path 62 are joined by switching the junction valve 46 inserted between the first supply path 61 and the second supply path 62 from a blocked state to a connected state.

[0060] Here, in this embodiment, since the working unit 33 is an example of a "specific operation unit", the hydraulic cylinder 442 which is a hydraulic actuator of the working unit 33 is an example of an "actuator of the specific operation unit". In this embodiment, as an example, the hydraulic cylinder 442 is connected to the second supply path 62 side, and hydraulic oil is supplied to the hydraulic cylinder 442 from at least the second pump 412 through the second supply path 62. In other words, when the junction valve 46 is in a shutoff state, the first supply path 61 for supplying hydraulic oil from the first pump 411 to the first traveling motor 431 and the swing motor 441 and the second supply path 62 for supplying hydraulic oil from the second pump 412 to the second traveling motor 432 and the hydraulic cylinder 442 are separated.

[0061] On the other hand, when the junction valve 46 is in an open state, a first supply path 61 for supplying hydraulic oil from the first pump 411 to the first traveling motor 431 and the swing motor 441 and a second supply path 62 for supplying hydraulic oil from the second pump 412 to the second traveling motor 432 and the hydraulic cylinder 442 merge.

[0062] That is, when the traveling unit 31 is operating independently, as shown in Fig. 3, the spools of the directional control valves 51, 52 move to block the traveling detection path 74, so that the pilot oil flowing through the traveling detection path 74 is guided to the first control path 71 and the first pilot signal Si1 is boosted. However, since the working unit 33 is not operating, the second pilot signal Si2 is not boosted, the first auxiliary valve 471 is closed, and the first pilot signal Si1 is blocked, so that the first pilot signal Si1 is not input to the junction valve 46. Therefore, in the state shown in Fig. 3, the junction valve 46 is in a blocked state, and the first supply path 61 and the second supply path 62 are separated from each other.

[0063] In contrast, during "combined operation" in which both the traveling unit 31 and the specific operation unit (for example, the working unit 33) are operating, as shown in Fig. 4, the spool of the directional control valve 54 moves to block the work detection path 75, so that the pilot oil flowing through the work detection path 75 is guided to the second control path 72 and the second pilot signal Si2 is boosted. As a result, the first auxiliary valve 471 is opened, and the first pilot signal Si1 is input to the junction valve 46 via the first auxiliary valve 471 and the second auxiliary valve 472. Therefore, the junction valve 46 switches from the blocked state to the connected state, and in the state of Fig. 4, the first supply path 61 and the second supply path 62 are in a junction state.

[0064] Therefore, during "combined operation" in which the specific operation unit (working unit 33 as an example) operates while the traveling unit 31 is operating, the working fluid from the first pump 411 and the second pump 412 are merged, and the pressure reduction of the working fluid to the traveling unit 31 due to the operation of the specific operation unit can be suppressed. As a result, it is possible to suppress the occurrence of problems such as running shock (shock due to sudden speed change) or cornering in the traveling unit 31 without reducing the operating speed of the specific operation unit while traveling compared to when the vehicle is stopped.

[0065] More specifically, the junction valve 46 is brought into a communicating state by receiving a first pilot signal Si1 generated during operation of the traveling unit 31. A first auxiliary valve 471 and a second auxiliary valve 472 are provided on an input path (first control path 71) of the first pilot signal Si1 to the junction valve 46. The first auxiliary valve 471 passes the first pilot signal Si1 when a second pilot signal Si2 generated during operation of the actuator (hydraulic cylinder 442) is input. The second auxiliary valve 472 blocks the first pilot signal Si1 when a third pilot signal Si3 generated during operation of the swing motor 441 is input.

[0066] As a result, by using the hydraulic circuit configuration without complex control, it is possible to merge the first supply path 61 and the second supply path 62 during "combined operation" when both the traveling part 31 and the specific operation part (the working part 33 as one example) are operating, as described above.

[0067] Moreover, while the actuator (hydraulic cylinder 442) is not in operation, the second pilot signal Si2 is not input to the first auxiliary valve 471, and therefore the first pilot signal Si1 is blocked by the first auxiliary valve 471. Therefore, as described above, while the traveling portion 31 is operating independently, it is possible to cancel the confluence of the first supply path 61 and the second supply path 62.

[0068] Furthermore, while the swing motor 441 is in operation, the third pilot signal Si3 is input to the second auxiliary valve 472, and the first pilot signal Si1 is blocked by the second auxiliary valve 472. Therefore, as described above, even if the traveling section 31 is in operation, when the swing section 32 of the work vehicle 3 operates, it is possible to cancel the confluence of the first supply line 61 and the second supply line 62.

[0069] Here, in this embodiment, the third pilot signal Si3 is a signal that is linked to the operation of the swing motor 441. Specifically, as shown in Fig. 5, a third control path 73 through which the third pilot signal Si3 passes is a path branched off from a swing detection path 76 connected to a remote control valve 45 for operating the swing motor 441 via a shuttle valve 49.

[0070] Therefore, when an operation is performed using the operating device 35 to operate the rotation motor 441, the pilot oil flowing through the rotation detection path 76 is guided to the third control path 73 via the shuttle valve 49, and the third pilot signal Si3 is boosted, causing the first pilot signal Si1 to be blocked by the second auxiliary valve 472.

[0071] This makes it possible, with a relatively simple configuration, to exceptionally cancel the confluence of the first supply path 61 and the second supply path 62 when the swivel part 32 of the work vehicle 3 is in operation. Fig. 5 illustrates an example of "combined operation" in which both the traveling part 31 and the specific operation part (the working part 33 as an example) are in operation, but this is not limiting, and even if at least one of the traveling part 31 and the working part 33 is not in operation (stopped), the confluence of the first supply path 61 and the second supply path 62 is canceled when the swivel part 32 is in operation.

[0072] In this embodiment, the first pilot signal Si1 is a signal that is linked to the movement of the spools of the directional control valves 51, 52 corresponding to the first traveling motor 431 and the second traveling motor 432. Therefore, the operating state of the traveling unit 31 (the first traveling motor 431 and the second traveling motor 432) can be reflected in the first pilot signal Si1 with a relatively simple configuration.

[0073] In this embodiment, the second pilot signal Si2 is a signal that is linked to the movement of the spool of the directional control valve 54 corresponding to the actuator (hydraulic cylinder 442). Therefore, the operating state of the specific action part (hydraulic cylinder 442) can be reflected in the second pilot signal Si2 with a relatively simple configuration.

[0074] As described above, in this embodiment, the first supply path 61 and the second supply path 62 join only during "combined operation" when both the traveling unit 31 and the specific operation unit (the working unit 33 as an example) are operating, and only when the swivel unit 32 is not operating (stopped). Therefore, in addition to the above-mentioned example, for example, the first supply path 61 and the second supply path 62 are separated when the traveling unit 31, the swivel unit 32 and the working unit 33 are not operating, when the working unit 33 or the swivel unit 32 is operating independently, and during combined operation when both the traveling unit 31 and the swivel unit 32 are operating.

[0075] Fig. 6 is a flowchart showing an example of processing relating to control of the junction valve 46, among other steps in the control method for the work vehicle 3 according to this embodiment. As described above, the work vehicle 3 according to this embodiment basically realizes a series of operations as shown in Fig. 6 by using a hydraulic circuit configuration.

[0076] First, whether the process proceeds to step S2 or step S8 is determined depending on whether the traveling unit 31 is in operation (S1). At this time, if the traveling unit 31 is in operation (S1: Yes), a first pilot signal Si1 is generated (S2).

[0077] Next, depending on whether the working unit 33 is operating, it is determined whether the process proceeds to step S4 or step S8 (S3). At this time, if the working unit 33 is operating (S3: Yes), a second pilot signal Si2 is generated (S4).

[0078] Next, depending on whether the swivel unit 32 is operating, it is determined whether the process proceeds to step S6 or step S7 (S5). At this time, if the swivel unit 32 is not operating (S5: No), the junction valve 46 is opened (S6), and the first supply path 61 and the second supply path 62 join together.

[0079] On the other hand, when the traveling unit 31 is not operating (S1: No), when the working unit 33 is not operating (S3: No), or when the third pilot signal Si3 is generated (S7), the junction valve 46 is shut off (S8), and the first supply path 61 and the second supply path 62 are separated.

[0080] The work vehicle 3 repeatedly executes the processes of steps S1 to S8 above. However, the flowchart shown in Fig. 6 is merely an example, and processes may be added or omitted as appropriate, and the order of processes may be changed as appropriate.

[0081] [4] Variations Below, we will list some modified examples of the embodiment 1. The modified examples explained below can be applied in appropriate combinations.

[0082] The control method in the present disclosure is not limited to being embodied in a hydraulic circuit configuration as in the first embodiment, and may be embodied, for example, by a control system including a computer system. The computer system is mainly composed of one or more processors and one or more memories as hardware. The control method for the work vehicle 3 in the present disclosure is realized by the processor executing a program recorded in the memory of the computer system. The program may be pre-recorded in the memory of the computer system, may be provided through an electric communication line, or may be provided by being recorded on a non-transitory recording medium such as a memory card, an optical disk, or a hard disk drive that is readable by the computer system. In addition, some or all of the functional units included in the control system may be configured with electronic circuits.

[0083] Furthermore, it is not essential for the control system that at least some of the functions of the control system are concentrated in one housing, and the components of the control system may be distributed across multiple housings. Furthermore, at least some of the functions of the control system may be realized by the cloud (cloud computing) or the like.

[0084] In addition, the working fluid is not limited to hydraulic oil, but may be, for example, a gas such as air or other fluid. When the working fluid is air, a pneumatic actuator driven by air pressure such as compressed air is used as the actuator.

[0085] Further, the directional control valves 51 to 54 are not limited to the pilot type, and may be, for example, a manual (wire) type. If the directional control valves 51 to 54 are of the manual type, the spools of the directional control valves 51 to 54 are directly driven by a wire in conjunction with the operation of the operating device 35.

[0086] The operation lever of the operation device 35 may be an electric operation device that outputs an electric signal (operation signal) corresponding to the operation of the user (operator) to the control device, thereby accepting various operations by the user. In this case, the control device can control the hydraulic actuator by controlling, for example, a control valve (solenoid valve) provided in place of the remote control valve 45 in response to the operation of the operation device 35 (operation lever).

[0087] Furthermore, it is sufficient that the actuator of the specific operation unit is supplied with working fluid (hydraulic oil) from at least one of the first supply path 61 and the second supply path 62. In other words, the hydraulic cylinder 442 (an example of the actuator of the specific operation unit), which is the hydraulic actuator of the working unit 33, may be supplied with hydraulic oil from the first pump 411 through the first supply path 61, or may be supplied with hydraulic oil from both the first pump 411 and the second pump 412.

[0088] [Appendix to the invention] The following will provide an overview of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0089] <Appendix 1> supplying a working fluid through a first supply passage to a first travel motor in a travel section of the work vehicle; supplying the working fluid to a second traveling motor in the traveling portion through a second supply passage; When a specific operation unit other than the traveling unit of the work vehicle is operated during operation of the traveling unit, the first supply line and the second supply line are merged. A method for controlling a work vehicle.

[0090] <Appendix 2> When the rotating unit of the work vehicle is operated during the operation of the traveling unit, the merging of the first supply path and the second supply path is released. 2. A method for controlling a work vehicle as described in claim 1.

[0091] <Appendix 3> When the traveling unit is operating independently, the merging of the first supply path and the second supply path is released. 3. A method for controlling a work vehicle according to claim 1 or 2.

[0092] <Appendix 4> The first supply passage is a passage that supplies the working fluid from the first pump to the first travel motor and a rotation motor in a rotation portion of the work vehicle, The second supply passage is a passage that supplies the working fluid from the second pump to the second traction motor, The actuator of the specific operation unit is supplied with the working fluid from at least one of the first supply path and the second supply path, a merging valve inserted between the first supply path and the second supply path is switched from a blocking state to a communicating state, thereby merging the first supply path and the second supply path; A control method for a work vehicle according to any one of claims 1 to 3.

[0093] <Appendix 5> The junction valve is brought into a communicating state by receiving a first pilot signal generated during operation of the traveling portion, a first auxiliary valve and a second auxiliary valve are provided on an input path of the first pilot signal to the junction valve, the first auxiliary valve passes the first pilot signal when a second pilot signal generated during operation of the actuator is input; The second auxiliary valve blocks the first pilot signal when a third pilot signal generated during operation of the swing motor is input. 5. A method for controlling a work vehicle as described in appendix 4.

[0094] <Appendix 6> The first pilot signal is a signal that is linked to the movement of a spool of a directional control valve corresponding to the first traveling motor and the second traveling motor. 6. A method for controlling a work vehicle as described in appendix 5.

[0095] <Appendix 7> The second pilot signal is a signal that is linked to the movement of a spool of a directional control valve corresponding to the actuator. 7. A method for controlling a work vehicle according to claim 5 or 6.

[0096] <Appendix 8> The third pilot signal is a signal linked to the operation of the swing motor. A method for controlling a work vehicle according to any one of appendixes 5 to 7. [Explanation of symbols]

[0097] 3. Work vehicles 31 Running part 32 Swivel section 33 Working section (specific operation section) 46 Junction valve 51~54 Directional valve 61 1st supply route 62 2nd supply route 301 First drive circuit 302 Second drive circuit 303 Merging circuit 411 First Pump 412 Second Pump 431 First Traction Motor 432 Second Travel Motor 441 Swing Motor 442 Hydraulic cylinder (actuator) 471 First auxiliary valve 472 Second auxiliary valve Si1 First pilot signal Si2 Second pilot signal Si3 3rd pilot signal

Claims

1. supplying a working fluid through a first supply passage to a first traveling motor in a traveling section of a work vehicle; supplying the working fluid to a second traveling motor in the traveling portion through a second supply passage; When a specific operation unit other than the traveling unit of the work vehicle is operated during operation of the traveling unit, the first supply line and the second supply line are merged. A method for controlling a work vehicle.

2. When a turning unit of the work vehicle is operated during operation of the traveling unit, the merging of the first supply path and the second supply path is released. A method for controlling a work vehicle according to claim 1.

3. When the traveling unit is operating independently, the merging of the first supply path and the second supply path is released. A method for controlling a work vehicle according to claim 1 or 2.

4. The first supply passage is a passage that supplies the working fluid from the first pump to the first travel motor and a rotation motor in a rotation portion of the work vehicle, The second supply passage is a passage that supplies the working fluid from the second pump to the second traveling motor, The actuator of the specific operation unit is supplied with the working fluid from at least one of the first supply path and the second supply path, a merging valve inserted between the first supply path and the second supply path is switched from a blocking state to a communicating state, thereby merging the first supply path and the second supply path; A method for controlling a work vehicle according to claim 1 or 2.

5. The junction valve is brought into a communicating state by inputting a first pilot signal that is generated during operation of the traveling portion, a first auxiliary valve and a second auxiliary valve are provided on an input path of the first pilot signal to the junction valve, the first auxiliary valve passes the first pilot signal when a second pilot signal generated during operation of the actuator is input; the second auxiliary valve blocks the first pilot signal when a third pilot signal generated during operation of the swing motor is input. A method for controlling a work vehicle according to claim 4.

6. The first pilot signal is a signal that is linked to a movement of a spool of a directional control valve corresponding to the first traveling motor and the second traveling motor. A method for controlling a work vehicle according to claim 5.

7. the second pilot signal is a signal that is linked to the movement of a spool of a directional control valve corresponding to the actuator; A method for controlling a work vehicle according to claim 5.

8. The third pilot signal is a signal linked to the operation of the swing motor. A method for controlling a work vehicle according to claim 5.

9. a first drive circuit that supplies working fluid through a first supply passage to a first travel motor in a travel section of the work vehicle; a second drive circuit that supplies the working fluid to a second travel motor in the travel unit through a second supply passage; A junction circuit that merges the first supply path and the second supply path when a specific operation unit other than the traveling unit of the work vehicle is operated during operation of the traveling unit. Work vehicle.

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