Work vehicles

Abstract

To provide a work vehicle capable of improving fuel economy and electricity cost by controlling the discharge flow rate of a hydraulic pump while comparing the operating speed of an operator with a reference operating speed.SOLUTION: A work vehicle 1 includes a lower body 2, an upper body 3, a driver's cab 4, an operating device 5, a traveling device 6, a controller 7, an inertia sensor 7a, a turning device 8, and a working device 9. The controller 7 is configured to control a first hydraulic pump 31 by comparing a traveling operation speed per unit time in the operating device 5 operated by an operator with an acceleration calculated from an acceleration signal detected by the inertia sensor 7a, and is configured to control a second hydraulic pump 32 by comparing a turning operation speed per unit time in the operating device 5 with an angular acceleration calculated from an angular velocity signal detected by the inertia sensor 7a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a work vehicle. [Background technology]

[0002] Conventionally, work vehicles having a speed sensor and an inertial sensor have been proposed (Patent Document 1: JP 2021-50541 A, Patent Document 2: JP 2021-50744 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-50541 [Patent Document 2] Patent Publication No. 2021-50744 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional work vehicle controllers control hydraulic pumps to discharge a flow rate corresponding to the amount of operation of controls, such as travel pedals and control levers, operated by the operator. However, the inertial mass required to move the machine body or upper body is large, making it impossible to move a large inertial mass body at maximum acceleration all at once; instead, it must be gradually moved and accelerated. Therefore, excess hydraulic oil exceeding the required flow rate is relieved and returned to the hydraulic oil tank without contributing to the work of hydraulic actuators, such as hydraulic motors and hydraulic cylinders. When the inertial mass is large, the hydraulic pump must discharge hydraulic oil at a low flow rate and high pressure. However, some operators may suddenly maximize the amount of operation of the controls in order to immediately start the machine body or upper body. When the operator suddenly maximizes the amount of operation of the controls, a high flow rate and high pressure of hydraulic oil is discharged from the hydraulic pump. When the inertial mass is large, excess hydraulic oil exceeding the flow rate required for acceleration is relieved and returned to the hydraulic oil tank, resulting in unnecessary energy consumption. This results in problems with reduced fuel and electricity efficiency. [Means for solving the problem]

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a work vehicle that is capable of improving fuel economy and electricity efficiency by controlling the discharge flow rate of a hydraulic pump while comparing the operating speed of an operator with a reference operating speed.

[0006] In one embodiment, the above problem is solved by the solution disclosed below.

[0007] The work vehicle according to the present invention comprises a first hydraulic pump, a hydraulic motor for traveling operated by pressure oil from the first hydraulic pump, a traveling device having the hydraulic motor for traveling, a second hydraulic pump, a hydraulic motor for swinging operated by pressure oil from the second hydraulic pump, a swing device in which the hydraulic motor for swinging is disposed, a lower body to which the traveling device is attached, an upper body rotatably disposed on the lower body, a working device attached to the upper body, a driver's cab disposed on the upper body, an operating device disposed in the driver's cab, an inertial sensor disposed on the upper body, and a controller having the inertial sensor, wherein the inertial sensor is configured to output an acceleration signal corresponding to the traveling acceleration of the vehicle body and to output an angular velocity signal corresponding to the angular velocity around the axis of a swing shaft of the swing device, and the controller 、 Calculated from the acceleration signal The above running acceleration and calculating a reference driving operation speed based on the calculated reference driving operation speed and a driving operation speed based on the operation of the operating device. The first hydraulic pump is controlled in comparison with the second hydraulic pump. The controller Angular acceleration calculated from the angular velocity signal A reference turning operation speed is calculated based on the reference turning operation speed and the turning operation speed based on the operation of the operation device. The second hydraulic pump is controlled in comparison with the first hydraulic pump.

[0008] With this configuration, the controller can control the discharge flow rate of the hydraulic pump within an appropriate range while comparing the operating speed of the operator with the reference operating speed, thereby improving fuel efficiency and electricity efficiency of the drive source that drives the hydraulic pump.

[0009] In one example, the controller Running Based on acceleration hand A first flow rate required for the traveling operation of the machine body Calculate , Calculated Calculate backward from the first flow rate hand per unit time The aforementioned Standard driving speed of The calculated speed is compared with the reference travel speed. hand When it is determined that the traveling operation speed per unit time is large, the first flow rate is discharged from the first hydraulic pump; and The controller Based on the angular acceleration handA second flow rate required for the upper body to rotate Calculate , Calculated per unit time calculated backward from the second flow rate The aforementioned Reference turning speed of The calculated speed is compared with the reference turning speed. hand When it is determined that the swing operation speed per unit time is high, the second hydraulic pump is configured to discharge the second flow rate. With this configuration, even if the operator suddenly maximizes the operation amount of the operating device, thereby exceeding the reference operation speed, it is possible to easily control the flow rate required for traveling and swing operations.

[0010] In one example, the controller may compare the reference driving speed with the reference driving speed. hand When it is determined that the travel operation speed per unit time is the same or smaller, a flow rate corresponding to the travel operation speed is discharged from the first hydraulic pump; and The controller Compared with the standard turning operation speed hand When it is determined that the swing operation speed per unit time is the same or lower, the second hydraulic pump is configured to discharge a flow rate according to the swing operation speed. With this configuration, when the operator operates the control device at a standard operation speed or lower, the flow rate is controlled according to the operator's operation, allowing the operator to operate without feeling uncomfortable.

[0011] As an example, the drive source of the first hydraulic pump and the second hydraulic pump is an engine, and both the first hydraulic pump and the second hydraulic pump are variable displacement swash plate pumps.As an example, the drive source of the first hydraulic pump and the second hydraulic pump is an electric motor, and both the first hydraulic pump and the second hydraulic pump are fixed displacement gear pumps. [Effects of the Invention]

[0012] According to the present invention, a work vehicle is realized that is capable of improving fuel efficiency and electricity consumption by having a controller that controls the discharge flow rate of the hydraulic pump within an appropriate range while comparing the operating speed of the operator with a reference operating speed. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic perspective view showing an example of a work vehicle according to this embodiment. [Figure 2] FIG. 2 is a schematic circuit diagram showing an example of a drive control system in the work vehicle shown in FIG. [Figure 3] FIG. 3 is a schematic flowchart illustrating an example of an operational procedure for flow rate control related to the traveling operation of the work vehicle shown in FIG. [Figure 4] FIG. 4 is a schematic flowchart illustrating an example of an operational procedure for flow rate control related to a turning operation in the work vehicle shown in FIG. [Figure 5] FIG. 5 is a schematic graph showing an example of flow rate control related to the traveling operation of the work vehicle shown in FIG. [Figure 6] FIG. 6 is a schematic graph showing an example of flow rate control related to a turning operation in the work vehicle shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an example of a work vehicle 1 according to this embodiment, and is a perspective view from above the left front. A hydraulic excavator will be used as an example of the work vehicle 1 according to this embodiment. As configurations other than those described above, a track loader, a carrier, or the like can also be used as the work vehicle 1. The work vehicle 1 is equipped with a traveling device 6 and a turning device 8, and the axis P1 of the turning shaft when the vehicle body is in a horizontal position is in the vertical direction, which is the Z-axis direction. For ease of explanation, arrows may be used in the drawings to indicate the up / down, left / right, and front / rear directions. Furthermore, in all drawings used to explain the embodiment, members having the same functions are designated by the same reference numerals, and repeated explanations of such members may be omitted.

[0015] As shown in Fig. 1, a work vehicle 1 comprises a travellable lower body 2, a swiveling upper body 3 disposed on the lower body 2, a working device 9 attached to the upper body 3, and a cab 4 disposed on the upper body 3. An operating device 5 is provided in the cab 4, where an operator sits and operates various tasks including traveling and swinging. The part surrounded by the dashed dotted line P2 in the figure is a schematic diagram showing an example of the arrangement of the operating device 5.

[0016] The operator's cab 4 is equipped with a seat 98 for the operator to sit in and a steering wheel 99 for the operator to operate, and is also equipped with an operating device 5 for controlling the operation of the traveling device 6, the turning device 8, the working device 9 (shovel device 9a), the working device 19 (blade device 19a), and other known working devices.

[0017] As an example, the left operation lever 5a is operated to operate the swing device 8 and the arm 51c. As an example, the upper body 3 is rotated counterclockwise by moving the left operation lever 5a leftward, and the swing speed is adjusted by the amount of operation of the left operation lever 5a. As an example, the upper body 3 is rotated clockwise by moving the left operation lever 5a rightward, and the swing speed is adjusted by the amount of operation of the left operation lever 5a. As an example, the boom 51b and the bucket 51d are operated by operating the right operation lever 5b. As an example, the blade lever 5c is operated to operate the blade 51a. As an example, the travel pedal 5d is operated to operate the traveling device 6, and the travel speed is adjusted by the amount of operation of the travel pedal 5d. As an example, the brake pedal 5e is operated to stop the traveling device 6. As an example, the boom swing / second boom pedal 5f is operated to adjust the swing direction of the boom 51b. The operating device 5 is not limited to the above configuration, but is set appropriately according to the configuration of the traveling device 6, the turning device 8, the working device 9 (shovel device 9a), the working device 19 (blade device 19a), or other known working devices.

[0018] The traveling device 6 of the work vehicle 1 is a four-wheel drive configuration having front running wheels 6a with tires fitted on the outer periphery of the wheels and rear running wheels 6b with tires fitted on the outer periphery of the wheels. As an example, the upper body 3 of the work vehicle 1 has a pair of left and right headlights 6c with built-in light sources that illuminate the front, and a pair of turn signals 6d that provide illumination for indicating left and right directions, and the work vehicle 1 is configured to be self-propelled on public roads.

[0019] The upper body 3 of the work vehicle 1 has a controller 7 and an inertial sensor 7a. As an example, the inertial sensor 7a is mounted on a control board of the controller 7. As an example, the inertial sensor 7a is separately arranged in a position close to the controller 7 and is signal-connected to the controller 7. The controller 7 and the inertial sensor 7a are both arranged in the upper body 3. As an example, the controller 7 and the inertial sensor 7a are both arranged under the floor of the cab 4. In this specification, the inertial sensor 7a is synonymous with the inertial measurement unit.

[0020] As shown in FIG. 1, the inertial sensor 7a is configured to output an angular velocity signal corresponding to the angular velocity around the Z-axis axis and an acceleration signal corresponding to the vehicle's traveling acceleration. The area surrounded by the dashed-dotted line P3 in the figure is a schematic structural diagram of the inertial sensor 7a. The inertial sensor 7a is, for example, a one-chip IC, a substrate-mounted semiconductor package with a MEMS structure. For example, the inertial sensor 7a is configured to output signals corresponding to the angular velocity around the longitudinal axis, the angular velocity around the lateral axis, and the angular velocity around the vertical axis, as well as signals corresponding to the acceleration in the longitudinal direction, the acceleration in the lateral direction, and the acceleration in the vertical direction. Note that the inertial sensor 7a is not limited to the above configuration, and any known inertial sensor or inertial measurement device can be used as the inertial sensor 7a.

[0021] The work vehicle 1 is equipped with a hydraulically operated work implement 9 (shovel unit 9a), a work implement 19 (blade unit 19a), and other known work implements. As an example, the shovel unit 9a has a boom 51b, an arm 51c, and a bucket 51d. The bucket 51d may be replaced with a known work attachment. The boom 51b is attached to the upper body 3 so as to be swingable in the vertical direction, including the up-down direction and a front-to-back component. As an example, a boom bracket 51e is provided between the upper body 3 and the boom 51b. The boom bracket 51e allows the boom 51b to swing in the left-right direction and a left-to-right direction, including a front-to-back component, relative to the upper body 3. Note that the boom bracket 51e may be omitted. The arm 51c is attached to the boom 51b so as to be swingable in the vertical direction, including the up-down direction and a front-to-back component. The bucket 51d is attached to the arm 51c so as to be swingable in the vertical direction, including the up-down direction and a front-to-back component.

[0022] As an example, both the working device 9 and the working device 19 are operated by hydraulic cylinders 18. The blade device 19a has a blade 51a. The blade 51a is attached to the lower body 2 so as to be swingable in the up-down direction and in the up-down direction, including a front-to-back component. As an example, the blade 51a is configured to swing up and down relative to the lower body 2 by a blade cylinder 18a. As an example, the arm 51c is configured to swing up and down relative to the boom 51b by an arm cylinder 18b. As an example, the bucket 51d is configured to swing up and down relative to the arm 51c by a bucket cylinder 18c. As an example, the boom 51b is configured to swing up and down relative to the upper body 3 by a boom cylinder 18d. As an example, the boom 51b is configured to swing left and right relative to the upper body 3 by a swing cylinder (not shown).

[0023] 2 is a schematic circuit diagram showing an example of a drive control system in the working vehicle 1. Solid lines in the figure simply show connections in the hydraulic system, and dashed lines in the figure simply show connections in the electrical signal system.

[0024] The traveling device 6 according to this embodiment is equipped with a hydrostatic continuously variable transmission (abbreviated as HST). The engine 20 is the drive source for the first hydraulic pump 31. As an example, the first hydraulic pump 31 is a variable displacement swash plate pump. The traveling hydraulic motor 16 is connected to a gear case, and power is transmitted from the gear case to a rear axle, and further to the left and right rear traveling wheels 6b, and from the gear case to a front axle via a propeller shaft, and further to the left and right front traveling wheels 6a (not shown). Note that the above configuration is one example, and the traveling device 6 may be configured without an HST.

[0025] The engine 20 is controlled by an engine control unit 30. The engine control unit 30 is signal-connected to the controller 7. The work vehicle 1 has a lead battery 56 that supplies power to the engine control unit 30 and the controller 7 when the work vehicle 1 is started.

[0026] The work vehicle 1 is equipped with a traveling hydraulic motor 16, a swing hydraulic motor 17, and hydraulic cylinders 18 (blade cylinder 18a, arm cylinder 18b, bucket cylinder 18c, boom cylinder 18d, and other known hydraulic cylinders). The work vehicle 1 also has connection ports (not shown) for hydraulically operating various attachments attached as options. Note that FIG. 2 is a schematic diagram, and only essential parts of the hydraulic system and electrical signal system connections are shown.

[0027] The work vehicle 1 has a first hydraulic pump 31 and a traveling hydraulic motor 16 that is operated by pressurized oil from the first hydraulic pump 31. In this example, a first check valve 43 is provided on each of the output sides of the first hydraulic pump 31, and a first relief valve 41 is provided on the output side of each of the first check valves 43.

[0028] The work vehicle 1 has a second hydraulic pump 32 and a swing hydraulic motor 17 that is operated by pressure oil from the second hydraulic pump 32. In this example, the swing hydraulic motor 17 is connected to the secondary side of the hydraulic motor control valve 11.

[0029] As an example, the control valve unit 10 is configured by connecting in parallel the primary sides of the swing hydraulic motor control valve 11, hydraulic cylinder control valve 12a, hydraulic cylinder control valve 12b, hydraulic cylinder control valve 12c, hydraulic cylinder control valve 12d, and second relief valve 42. The secondary side of the second relief valve 42 forms a return flow path, and hydraulic oil exceeding the set pressure is returned to the hydraulic oil tank 54. Note that the above configuration is just an example, and the number of various control valves that configure the control valve unit 10 may be increased or decreased, and a service port control valve may be included as necessary.

[0030] The control device 5 operated by the operator is signal-connected to the controller 7. As an example, the control device 5 has a left control lever 5a, a right control lever 5b, a blade lever 5c, a travel pedal 5d, a brake pedal 5e, and a boom swing / second boom pedal 5f. The operator operates the control device 5 to operate the traveling device 6, the swing device 8, the work device 9, and other known work devices. When the control device 5 is operated, an operation signal is sent to the controller 7.

[0031] Fig. 3 is a schematic flow chart showing the operation procedure of flow rate control related to traveling operation. Fig. 5 is a schematic graph showing an example of flow rate control related to traveling operation. Next, an example of control related to the traveling device 6 will be described below.

[0032] [Example of control related to running gear] In step S1 of Fig. 3, the controller 7 receives a predetermined signal transmitted in response to the operator's operation of the traveling pedal 5d and determines whether the traveling pedal 5d has started to operate. If the controller 7 determines that the traveling pedal 5d has started to operate, the process proceeds to step S2. On the other hand, if the controller 7 determines that the traveling pedal 5d has not started to operate, the controller 7 does not start control of the traveling operation, but maintains a standby state, and ends control of the traveling operation after a predetermined time.

[0033] 3, the controller 7 calculates the running acceleration from the acceleration signal of the inertial sensor 7a, calculates a first flow rate required for the running operation of the machine body based on the calculated running acceleration, and calculates a reference running operation speed per unit time by back-calculating from the calculated first flow rate. After step S2, the process proceeds to step S3.

[0034] In step S3 of Fig. 3, the controller 7 compares the calculated reference traveling operation speed with the traveling operation speed based on the operation amount of the traveling pedal 5d. If the controller 7 determines that the traveling operation speed is higher than the reference traveling operation speed, the process proceeds to step S4. On the other hand, if the controller 7 determines that the traveling operation speed is the same as or lower than the reference traveling operation speed, the process proceeds to step S5.

[0035] The controller 7, which has determined that the traveling operation speed is greater than the reference traveling operation speed and has transitioned to step S4, causes the first hydraulic pump 31 to discharge the first flow rate (see the left side of the graph in FIG. 5), and then transitions to step S6.

[0036] On the other hand, the controller 7, which has determined that the travel operation speed is equal to or smaller than the reference travel operation speed and has transitioned to step S5, causes the first hydraulic pump 31 to discharge a flow rate corresponding to the travel operation speed (see the right side of the graph in FIG. 5), and then transitions to step S6.

[0037] In step S6 of Figure 3, when the operator releases the travel pedal 5d, pressure oil stops being discharged from the first hydraulic pump 31, and the machine decelerates and stops. When the controller 7 determines that the travel pedal 5d has stopped operating and returned to its initial state, it ends control of the travel operation. On the other hand, when the controller 7 determines that the travel pedal 5d has not returned to its initial state and has not stopped operating, it returns to the position before step S2.

[0038] According to this embodiment, the controller 7 receives an acceleration signal from the inertial sensor 7a when the machine is traveling, and controls the first hydraulic pump 31 by comparing the operation speed of the traveling pedal 5d by the operator with the reference traveling operation speed, thereby improving fuel efficiency and electricity efficiency.

[0039] Fig. 4 is a schematic flow chart showing the operation procedure of flow rate control related to a swing operation. Fig. 6 is a schematic graph showing an example of flow rate control related to a swing operation. Next, an example of control related to the swing device 8 will be described below.

[0040] [Example of control related to a slewing device] In step S11 of Fig. 4, the controller 7 receives a predetermined signal transmitted in response to the operation of the left operation lever 5a by the operator and determines whether the left operation lever 5a has started. If the left operation lever 5a has started and it is determined that the vehicle will turn left, or if it is determined that the vehicle will turn right, the process proceeds to step S12. On the other hand, if it is determined that the left operation lever 5a has not started, the controller 7 does not start control of the turning operation, but maintains a standby state, and ends control of the turning operation after a predetermined time.

[0041] 4, the controller 7 calculates the angular acceleration from the angular velocity signal of the inertial sensor 7a per unit time, calculates a second flow rate required for the swing operation of the upper body 3 based on the calculated angular acceleration, and calculates a reference swing operation speed per unit time by back-calculating from the calculated second flow rate. After step S12, the process proceeds to step S13.

[0042] 4, the controller 7 compares the calculated reference traveling operation speed with the turning operation speed based on the operation amount of the left operating lever 5a. If it is determined that the turning operation speed is greater than the reference turning operation speed, the process proceeds to step S14. On the other hand, if it is determined that the turning operation speed is equal to or smaller than the reference turning operation speed, the process proceeds to step S15.

[0043] The controller 7, which has determined that the swing operation speed is greater than the reference swing operation speed and has transitioned to step S14, causes the second hydraulic pump 32 to discharge the second flow rate (see the left side of the graph in FIG. 6), and then transitions to step S16.

[0044] On the other hand, the controller 7, which has determined that the swing operation speed is equal to or smaller than the reference swing operation speed and has transitioned to step S15, causes the second hydraulic pump 32 to discharge a flow rate corresponding to the swing operation speed (see the right side of the graph in FIG. 6), and then transitions to step S16.

[0045] 4, when the operator releases the left operation lever 5a or manually returns the left operation lever to the neutral position, the second hydraulic pump 32 stops discharging pressurized oil, and the upper body 3 decelerates and stops. When the controller 7 determines that the left operation lever 5a has stopped operating and returned to its initial state, it ends control of the swing operation. On the other hand, when the controller 7 determines that the left operation lever 5a has not returned to its initial state and has not stopped operating, it returns to the position before step S12.

[0046] According to this embodiment, the controller 7 receives an angular velocity signal from the inertial sensor 7a when the upper body 3 is rotated, and controls the second hydraulic pump 32 by comparing the operation speed of the left operation lever 5a by the operator with the reference rotation operation speed, thereby improving fuel efficiency and electricity efficiency.

[0047] The drive source of the work vehicle 1 is not limited to the configuration described above, and may be a hybrid configuration that uses both an engine and an electric motor, or may be a configuration that uses an electric motor. The traveling device 6 is not limited to the configuration described above, and may be a configuration that includes crawlers. In this way, the work vehicle 1 may be modified as appropriate to suit the specifications, etc. [Explanation of symbols]

[0048] 1. Work vehicles 2 Lower body 3. Upper body 4. Driver's cab 5 Operating device, 5a Left operating lever, 5b Right operating lever, 5c Blade lever, 5d Travel pedal, 5e Brake pedal, 5f Boom swing / second boom pedal, 6 Traveling device, 6a Front traveling wheel, 6b Rear traveling wheel, 6c Headlight, 6d Turn signal 7 Controller, 7a Inertial Sensor 8 Swivel 9 Work equipment, 9a Shovel equipment 10 Control valve unit 11. Control valve for hydraulic motor 12a, 12b, 12c, 12d Control valves for hydraulic cylinders 16 Hydraulic motor for travel 17 Swing hydraulic motor 18 hydraulic cylinder, 18a blade cylinder, 18b arm cylinder, 18c bucket cylinder, 18d boom cylinder 19 Work equipment, 19a Blade equipment 20 Engine 31 First hydraulic pump 32 Second hydraulic pump 41 First relief valve 42 Second relief valve 43 First check valve 44 Second check valve 51a Earth removal plate 51b Boom 51c Arm 51d Bucket 51e Boom Bracket 54 Hydraulic oil tank 56 Lead-acid battery P1 Axis of the rotation axis

Claims

1. a first hydraulic pump, a hydraulic motor for traveling operated by pressure oil from the first hydraulic pump, a traveling device having the hydraulic motor for traveling, a second hydraulic pump, a hydraulic motor for swinging operated by pressure oil from the second hydraulic pump, a swing device in which the hydraulic motor for swinging is disposed, a lower body to which the traveling device is attached, an upper body rotatably disposed on the lower body, a working device attached to the upper body, a driver's cab disposed on the upper body, an operating device disposed in the driver's cab, an inertial sensor disposed on the upper body, and a controller having the inertial sensor, wherein the inertial sensor is configured to output an acceleration signal corresponding to the traveling acceleration of the machine body and to output an angular velocity signal corresponding to the angular velocity around the axis of a swing shaft of the swing device, The controller is configured to calculate a reference traveling operation speed based on the traveling acceleration calculated from the acceleration signal, and to control the first hydraulic pump by comparing the calculated reference traveling operation speed with a traveling operation speed based on the operation of the operating device; and The controller is configured to calculate a reference turning operation speed based on the angular acceleration calculated from the angular velocity signal per unit time, and to control the second hydraulic pump by comparing the calculated reference turning operation speed with a turning operation speed based on the operation of the operating device. A work vehicle characterized by:

2. the controller calculates a first flow rate required for the traveling operation of the machine body based on the traveling acceleration, calculates the reference traveling operation speed per unit time by back-calculating from the calculated first flow rate, and when it is determined that the traveling operation speed per unit time is greater than the reference traveling operation speed, causes the first hydraulic pump to discharge the first flow rate; The controller calculates a second flow rate required for the swing operation of the upper body based on the angular acceleration, calculates the reference swing operation speed per unit time by back-calculating from the calculated second flow rate, and when it determines that the swing operation speed per unit time is greater than the reference swing operation speed, causes the second hydraulic pump to discharge the second flow rate.

2. The work vehicle according to claim 1,

3. When the controller determines that the travel operation speed per unit time is equal to or smaller than the reference travel operation speed, the controller causes the first hydraulic pump to discharge a flow rate corresponding to the travel operation speed; and The controller is configured to discharge a flow rate corresponding to the swing operation speed from the second hydraulic pump when it determines that the swing operation speed per unit time is the same as or smaller than the reference swing operation speed.

3. The work vehicle according to claim 2, wherein:

4. The drive source of the first hydraulic pump and the second hydraulic pump is an engine, and the first hydraulic pump and the second hydraulic pump are both variable displacement swash plate pumps. The work vehicle according to any one of claims 1 to 3,

5. The drive source of the first hydraulic pump and the drive source of the second hydraulic pump are electric motors, and the first hydraulic pump and the second hydraulic pump are both fixed displacement gear pumps. The work vehicle according to any one of claims 1 to 3,

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