Work vehicle

Abstract

Provided is a work vehicle in which a first electric motor (30) for driving a work device (4), a second electric motor (40) for driving front wheels (2), and a battery (50) for supplying electric power to the first electric motor (30) and the second electric motor (40) are provided on the rear lower side of an operation part (5). A mode switch (15) is provided in the operation part (5), and for each mode selected by the mode switch (15), the drive conditions for the first electric motor (30) and the second electric motor (40) are set in advance. When a mode is selected via the mode switch (15), the output rotation of the first electric motor (30) is not increased or reduced by the output rotation of the second electric motor (40), and the first electric motor (30) is driven at a preset power consumption, whereby any variation in power consumption can be suppressed and the time during which work can be performed can be reliably kept long.

Description

Work vehicles

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

[0002] A known work vehicle has a drive motor that drives the rear wheels, a work motor that drives a work device that cuts grass, and a battery that supplies power to the drive motor and the work motor, all located below and behind the control unit, and has a control table that defines the correspondence between maximum vehicle speed values ​​and blade rotation speed values ​​for each mode selected by a mode switch located on the control unit, and changes the maximum vehicle speed value based on the blade rotation speed (Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2018-196354

[0004] However, in the technology of Patent Document 1, the output rotation of the driving motor is increased or decreased depending on the output rotation of the work motor, which causes the battery power consumed by the work motor and the driving motor to increase or decrease, and in some cases this can shorten the time available for work.

[0005] Therefore, the present invention provides a work vehicle that can ensure a long period of time during which work can be performed.

[0006] The present invention, which has solved the above-mentioned problems, is as follows: That is, the invention described in claim 1 is a work vehicle having wheels (2, 3) provided below a body frame (1), a working device (4) for cutting grass provided in front of the body frame (1), and a control unit (5) on which an operator rides provided above the body frame (1), wherein a first electric motor (30) for driving the working device (4), a second electric motor (40) for driving the front wheels (2), and a battery (50) for supplying power to the first electric motor (30) and the second electric motor (40) are provided below and behind the control unit (5), a mode switch (15) is provided in the control unit (5), drive conditions for the first electric motor (30) and the second electric motor (40) are preset for each mode selected by the mode switch (15), and when a mode is selected by the mode switch (15), the first electric motor (30) is driven at a power level equal to or lower than the preset power level.

[0007] According to the present invention, fluctuations in power consumption can be suppressed, and a longer period of time during which work can be performed can be secured.

[0008] 1 is a perspective view of a work vehicle viewed from the front left side; 2 is a perspective view of the front part of the electric motor compartment viewed from the rear left side; 3 is a perspective view of the rear part of the electric motor compartment viewed from the rear left side; 4 is a plan view of the electric motor compartment; 5 is a perspective view of the electric motor viewed from the rear left side; 6 is a plan view of the electric motor; 7 is a rear view of the electric motor; 8 is a perspective view of the battery viewed from the rear left side; 9 is a plan view of the electric motor compartment with the battery mounted thereon; 10 is a plan view of the electric motor and inverter device; 11 is a left side view of the electric motor and inverter device; 12 is a transmission diagram of the output rotation of the electric motor; 13 is a connection diagram of the controller; 14 is an explanatory diagram of modes 1 to 3 selected by the mode switch; 15 is an explanatory diagram of the power circuit and output wiring; 16 is an explanatory diagram of the maximum output rotation in modes 1 to 3; 17 is a plan view of the steering column and display unit; 18 is a block diagram of the rotation control of the electric motor; 19 is a side view of the work vehicle;

[0009] As shown in FIG. 1 , the work vehicle has a pair of left and right front wheels 2 provided at the front lower portion of a body frame 1 , and a pair of left and right rear wheels 3 provided at the rear lower portion of the body frame 1 .

[0010] A working device 4 for cutting grass growing in the field is provided at the front of the body frame 1, a control unit 5 on which the operator sits is provided at the rear of the working device 4, a safety frame (ROPS) 6 for protecting the operator is provided at the rear of the control unit 5, a grass collection container 7 for storing the cut grass is provided at the rear of the safety frame 6, and an electric motor room 8 is provided below the grass collection container 7 in which a second electric motor 40 for driving the front wheels 2, a battery 50, etc. are placed.

[0011] A steering column 10 supporting a steering wheel 108 is provided in front of the operator's seat in the control section 5. A monitor that displays the output rotation speed of the second electric motor 40 and the like is provided at the top of the steering column 10, and the lower part is fixed to the front part of the floor 106.

[0012] A brake pedal 11 for reducing the rotation speed of the front wheels 2 is provided on the left side of the steering column 10 on the floor 106, and an accelerator pedal 12 for increasing or decreasing the output rotation speed of the second electric motor 40 for driving the front wheels 2 is provided on the right side. The depression amount of the accelerator pedal 12 is measured by an angle sensor 12S attached to the base of the accelerator pedal 12.

[0013] The area above the front wheel 2 is covered with a fender 13, and on the fender 13 located to the right of the driver's seat is provided a gearshift lever 14 for operating an inverter device 35 that increases or decreases the output rotation of a first electric motor 30 for driving the working implement 4, and on the right side of the gearshift lever 14 is provided a mode switch 15 for setting the power consumption of the first electric motor 30 and the maximum output rotation and angular acceleration of the second electric motor 40. The amount of operation of the gearshift lever 14 is measured by an angle sensor 14S attached to the base of the gearshift lever 14.

[0014] The rear of the working device 4 and the front of the grass collection container 7 are connected by a chute 16 extending in the front-to-rear direction, and a blower 17 for exhausting air into the chute 16 is provided in the middle of the front-to-rear direction of the chute 16.

[0015] A pair of left and right link arms 18 are provided at the front of the left and right walls of the grass collection container 7. The front parts of the link arms 18 are fixed to the left and right parts of the safety frame 6 so as to be able to swing freely, and the safety frame 6 and the link arms 18 are connected by lifting parts 19 such as hydraulic cylinders, and the rear part of the bottom wall of the grass collection container 7 rests on a horizontal frame 21A of a support frame 21, which will be described later. This allows the grass collection container 7 to be raised and lowered by driving the lifting parts 19.

[0016] As shown in Figures 2 and 3, a first electric motor 30 and a second electric motor 40 are provided in the front electric motor chamber 8A of the electric motor chamber 8, and a battery 50 that stores electricity to be supplied to the first electric motor 30, etc. is provided in the rear electric motor chamber 8B.

[0017] In a plan view, the first electric motor 30 is provided to the left of the center line in the left-right direction of the vehicle frame 1, and the second electric motor 40 is provided to the right of the center line in the left-right direction of the vehicle frame 1. This reduces the weight difference between the weight applied to the left of the center line in the left-right direction of the vehicle frame 1 and the weight applied to the right of the center line in the left-right direction of the vehicle frame 1, thereby improving steering performance.

[0018] When viewed from the side, a support frame 20 extending upward from the body frame 1 is provided in the partition between the front electric chamber 8A and the rear electric chamber 8B, and a support frame 21 extending upward from the body frame 1 is provided at the rear end of the rear electric chamber 8B.

[0019] The support frame 20 is formed of a left vertical frame 20L extending upward from the middle of the left side of the body frame 1, a right vertical frame 20R extending upward from the middle of the right side of the body frame 1, and a horizontal frame 20A extending in the left-right direction connecting the upper parts of the left vertical frame 20L and the right vertical frame 20R.

[0020] The support frame 21 is formed of a left vertical frame 21L extending upward from the rear end of the left side of the body frame 1, a right vertical frame 21R extending upward from the rear end of the right side of the body frame 1, a horizontal frame 21A extending in the left-right direction connecting the upper parts of the left vertical frame 21L and the right vertical frame 21R, and a horizontal frame 21B extending in the left-right direction connecting the middle parts of the left vertical frame 21L and the right vertical frame 21R. The left part of the horizontal frame 21B extends further left than the left vertical frame 21L, and the right part extends further right than the right vertical frame 21R.

[0021] The middle portion of the left vertical frame 20L and the left end portion of the horizontal frame 21B are connected by a left front-rear frame 22L extending in the front-rear direction, and the middle portion of the right vertical frame 20R and the right end portion of the horizontal frame 21B are connected by a right front-rear frame 22R also extending in the front-rear direction. This allows the rear portion of the battery 50 to be located above the drive shaft 46 of the rear wheel 3, preventing the vehicle frame 1 from being significantly deformed.

[0022] The upper part of the left vertical frame 20L and the middle part of the left vertical frame 23L provided at the rear of the control unit 5 are connected by a left front-rear frame 24L extending in the fore-and-aft direction, and the upper part of the right vertical frame 20R of the support frame 20 and the middle part of the right vertical frame 23R provided at the rear of the control unit 5 are connected by a right front-rear frame 24R extending in the fore-and-aft direction.

[0023] 4, the longitudinal direction of the first electric motor 30 is aligned along the front-rear direction. The second electric motor 40 is aligned adjacent to the right side of the first electric motor 30, and the longitudinal direction of the second electric motor 40 is aligned along the front-rear direction.

[0024] A radiator 60 that cools the water that cools the first electric motor 30 and other components is provided on the outside of the left wall of the electric motor chamber 8, and a fan 61 that blows outside air toward the electric motor chamber 8 is provided between the radiator 60 and the first electric motor 30. A circular opening (not shown) is formed in the left wall of the electric motor chamber 8 at a location facing the fan 61. This makes it possible to suppress a temperature rise in the first electric motor 30 and other components, thereby preventing malfunctions of the first electric motor 30 and other components. The fan 61 can also be provided on the left side of the radiator 60.

[0025] 5 to 7, the output shaft 30A of the first electric motor 30 is connected to a reducer 31 provided below the first electric motor 30. The output shaft 31A of the reducer 31 extends forward and is connected to a work clutch 32 provided between the reducer 31 and the transmission path of the working device 4.

[0026] An output shaft 40A of the second electric motor 40 is connected to a reducer 41 provided in front of the second electric motor 40. The output shaft 41A of the reducer 41 extends forward, and the output shaft 41B extends rearward and is connected to a 4WD clutch 43 provided between the transmission path of the reducer 41 and the rear wheels 3, which switches between front-wheel drive and four-wheel drive.

[0027] As shown in Figure 8, the battery 50 is formed from four battery modules 50A. The upper parts of the four battery modules 50A are connected by a pair of left and right angle-shaped mounting frames 51 that are spaced a predetermined distance apart in the left-right direction and extend in the front-rear direction, and the lower parts are connected by a pair of left and right square pipe-shaped mounting frames 52 that are spaced a predetermined distance apart in the left-right direction and extend in the front-rear direction.

[0028] The front portion of the mounting frame 51 extends forward of the battery 50, and the rear portion extends rearward of the battery 50. The mounting frame 52 extends from the front end to the rear end of the battery 50.

[0029] As shown in Figure 9, the front part of the mounting frame 51 is removably fixed to the horizontal frame 20A of the support frame 20 by fastening members such as bolts, and the rear part is removably fixed to the horizontal frame 21A of the support frame 21 by fastening members such as bolts.

[0030] The left mounting frame 52 is placed on the left front-rear frame 22L, and the right mounting frame 52 is placed on the right front-rear frame 22R.

[0031] Openings 51A are formed in the front and rear of the mounting frame 51 to allow insertion of hanging hooks when replacing the battery 50. This allows the battery 50 to be easily attached to and detached from the support frames 20 and 21, making it easy to replace the battery 50.

[0032] 10 and 11 , an inverter device 35 for driving the first electric motor 30 is provided at a predetermined distance in the front-rear direction behind the first electric motor 30, and an inverter device 45 for driving the second electric motor 40 is provided at a predetermined distance in the front-rear direction behind the second electric motor 40. The inverter devices 35, 45 are also provided at a predetermined distance in the front-rear direction in front of the battery 50. This facilitates the routing of the first electric motor 30, the second electric motor 40, and the inverter devices 35, 45. Furthermore, air blown by the fan 61 passes through the gaps between the first electric motor 30, the second electric motor 40, and the inverter devices 35, 45, thereby efficiently cooling the first electric motor 30, the second electric motor 40, and the inverter devices 35, 45.

[0033] As shown in FIG. 12, the output rotation of the output shaft 30A of the first electric motor 30 is reduced in speed by the reducer 31 and then output from the output shafts 31A and 31B of the reducer 31.

[0034] The output rotation of the output shaft 31A is transmitted to a work PTO 33 via a work clutch 32 to drive the work device 4. In addition, the output rotation of the output shaft 31B is transmitted to a hydraulic pump 34 that pressurizes and feeds oil to be supplied to the lifting component 19 and the like.

[0035] The output rotation of the output shaft 30A of the first electric motor 30 is transmitted to a blower PTO 37 via a blower clutch 36 to drive the blower 17.

[0036] The output rotation of the output shaft 40A of the second electric motor 40 is reduced in speed by the reducer 41 and then output from the output shafts 41A and 41B of the reducer 41.

[0037] The output rotation of output shaft 41A is transmitted to a differential gear 42 for the front wheels to drive the front wheels 2, and the output rotation of output shaft 41B is transmitted to a differential gear 44 for the rear wheels via a 4WD clutch 43, and the output rotation of the differential gear 44 is transmitted to a drive shaft 46 to drive the rear wheels 3.

[0038] As shown in FIG. 13, the controller 70 of the work vehicle is made up of a processing unit 71 consisting of a CPU or the like, a memory unit 72 consisting of a ROM, RAM, a hard disk drive, flash memory or the like, and a communication unit 73 for data communication with the outside.

[0039] The processing unit 71 calculates the output value to be output to the inverter device 45 based on the amount of depression of the accelerator pedal 12, calculates the output value to be output to the inverter device 35 based on the amount of operation of the shift lever 14, and calculates the output value to be output to the inverter device 35 based on the power consumption of the first electric motor 30 that is preset for each mode selected by the mode switch 15.

[0040] Furthermore, when mode 1 to 3 is selected with mode switch 15, the calculation of the output value based on the depression amount of accelerator pedal 12 and the calculation of the output value based on the operation amount of gear shift lever 14 are restricted.

[0041] When the work vehicle is stopped, the memory unit 72 stores the mode that was selected by the mode switch 15 immediately before the work vehicle was stopped. This allows the work vehicle to be restarted in the mode that was selected immediately before the work vehicle was stopped without having to select a new mode by the mode switch 15.

[0042] The communication unit 73 transmits and receives data to and from a portable controller (not shown).

[0043] The input side of the controller 70 is connected via a predetermined input interface circuit to an angle sensor 12S that measures the amount of depression of the accelerator pedal 12, which increases or decreases the output rotation of the second electric motor 40 for driving, an angle sensor 14S that measures the amount of operation of the speed change lever 14, which increases or decreases the output rotation of the first electric motor 30 for work, a mode switch 15, etc.

[0044] The output side of the controller 70 is connected to an inverter device 35 that drives the first electric motor 30 for work, an inverter device 45 that drives the second electric motor 40 for travel, and the like via a predetermined output interface circuit.

[0045] As shown in FIG. 14 , in this embodiment, modes 1 to 3 can be selected using the mode switch 15. In mode 1, the power consumption, which is the setting condition of the first electric motor 30 for work, is preset to low power consumption, and the maximum output rotation, which is the setting condition of the second electric motor 40 for travel, is preset to low output rotation and low angular acceleration. In mode 2, the power consumption of the first electric motor 30 for work, is preset to medium power consumption, the maximum output rotation, which is the setting condition of the second electric motor 40 for travel, is preset to medium output rotation and medium angular acceleration. In mode 3, the power consumption of the first electric motor 30 for work, is preset to high power consumption, the maximum output rotation, which is the setting condition of the second electric motor 40 for travel, is preset to high output rotation and high angular acceleration. This allows for efficient mowing work depending on the type of turfgrass planted in the field, for example, by selecting mode 1 when the turfgrass is planted scattered throughout the field, and by selecting mode 3 when the turfgrass is planted densely in a specific part of the field. The setting conditions of the first electric motor 30 for work can also be set to maximum torque, maximum current value, and maximum power.

[0046] As shown in FIG. 15, power from the battery 50 is supplied to the controller 70 via a power wiring P1, to the inverter devices 35 and 45 via a power wiring P2, and to the first electric motor 30 and the second electric motor 40 via a power wiring P3.

[0047] The output value of controller 70 is input to inverter device 35 via output wiring S1, and the output value of inverter device 35 is input to first electric motor 30 via output wiring S2. The output value of controller 70 is input to inverter device 45 via output wiring S3, and the output value of inverter device 45 is input to second electric motor 40 via output wiring S4. In other words, the output rotations of first electric motor 30 and second electric motor 40 are individually controlled by inverter devices 35, 45, respectively, and the output rotation of first electric motor 30 is not affected by the output rotation of second electric motor 40, and vice versa. This allows the operator to accurately predict the working time and travel distance that can be achieved by first electric motors 30, 40 consuming power from battery 50 for each of modes 1 to 3, thereby enabling efficient planning of the mowing procedure.

[0048] Furthermore, the first electric motor 30 that drives the working device 4 consumes more power than the second electric motor 40 that drives the front wheels 2. As a result, when the first electric motor 30 and the second electric motor 40 consume power from the battery 50 to perform the mowing work, the working time of the mowing work can be extended by reducing the fluctuation in power consumption of the setting conditions of the first electric motor 30.

[0049] 16 shows the relationship between the depression amount [%] of the accelerator pedal 12 and the travel speed [km / h] of the work vehicle. When the accelerator pedal 12 is fully depressed, the depression amount is 100 [%], and the travel speed of the work vehicle is 20 [km / h].

[0050] 16, the maximum output rotation of the second electric motor 40 in modes 1 to 3 is set from low to high in the order of mode 1 to mode 3. As a result, in mode 1, the work vehicle travels slowly, so the load applied to the first electric motor 30 from the turfgrass via the work implement 4 is small, and fluctuations in the power consumption of the first electric motor 30 can be further suppressed.

[0051] Furthermore, it is preferable to set the maximum output rotation of the second electric motor 40 to a speed lower than the rated output rotation in modes 1 to 3. This makes it possible to maintain the maximum output rotation even when a load greater than the rated torque is applied to the second electric motor 40 from the field via the front wheels 2.

[0052] The angular acceleration of the second electric motor 40 in modes 1 to 3 is set from low to high in the order of mode 1 to mode 3. This allows the output rotation of the second electric motor 40 to be quickly increased, so that in the event of sudden rainfall, the system can be switched to mode 3 to quickly finish the mowing operation.

[0053] 17 to 19 , a steering column 10 is erected on a floor 106 above the front of a vehicle body 100, and a steering wheel 108 for steering is provided on top of the steering column 10. A driver's seat 109 is provided behind the steering wheel 108. A display panel 55 is provided on the top surface of the steering column 10, and is configured to display the load status of the first electric motor 30. That is, the display panel 55 is equipped with a color liquid crystal screen 57 and a display unit 58 that can display a plurality of segments in a band-like manner, and the color liquid crystal screen 57 is equipped with a remaining battery capacity display unit 59, a power-on time accumulation display unit 64, etc., and a motor shaft rotation speed display unit 62 for the first electric motor 30, etc., in the center of the color liquid crystal screen 57.

[0054] The display unit 58 indicates the workload level, and as the workload increases, the display unit 58 lights up in sequence from the end toward the center, and the more lights up, the higher the workload level can be visually recognized. In this embodiment, the display unit 58 is arranged symmetrically on the left and right, and as the workload level increases, the center side lights up in sequence.

[0055] The workload level is calculated based on the magnitude of the load current value of the first electric motor 30; the larger the load current value, the higher the workload level. The number of lights that light up in the display unit 58 is preset based on the level of this workload level.

[0056] 18 , in this embodiment, the load current of the first electric motor 30, which receives power from the battery 50, is detected by the current detection sensor 63, and the load current value is input to the inverter device 35. The inverter device 35 then outputs a predetermined rotation control signal, controlling the rotation speed of the first electric motor 30 to fall within a preset load current range (work motor control mode). This work motor control mode may also be selectable. Regardless of whether this selection is enabled or disabled, the current detection sensor 63 can detect the load current and display it on the display unit 58.

[0057] As described above, since the workload level can be displayed, it is possible to determine how much workload is being applied to the first electric motor 30, and by changing the vehicle speed of the traveling vehicle body 100, for example, depending on the workload, it is possible to continue work with a stable workload and improve work efficiency.

[0058] The display panel 55 is disposed on the upper surface of the steering column 10, and the display unit 58 is disposed in front of the outer periphery of the display panel 55. Therefore, the operator in the operator's seat 109 is positioned inside the grip of the circular steering wheel 108 and looks at the display unit 58 from above while operating the steering wheel 108. As shown in FIG. 19 , the operator's field of vision when looking at the display unit 58 includes the space between the front end of the working device 4 and the front gauge wheel 47 that supports the working device 4. That is, the steering wheel 108 has a grip that is inclined such that the front is slightly higher and the front is lower, and a line L1 connecting the higher side of the grip and the display unit 58 is positioned between the front end of the working device 4 and the gauge wheel 47. Therefore, by providing the display unit 58 in front of the outer periphery of the display panel 55 on the top of the steering column 10, the display unit 58 is within the operator's field of vision even when seated in the operator's seat 109, making it easy to check the workload level. Furthermore, since the line L1 connecting the display unit 58 and the higher side of the steering wheel 108 is located in front of the work device 4, it is possible to work while maintaining approximately the same line of sight or posture to view the display unit 58 and the status of the tip of the work device 4.

[0059] Furthermore, a line L2 connecting the lower side of the grip of the steering wheel 108 and the display unit 58 is set to be forward of the working device 4. Therefore, by bending down and keeping the line L2 in view, the worker can work while maintaining approximately the same line of sight or posture to view the display unit 58 and the distant situation.

[0060] The display unit 58 is arranged symmetrically as a pair of left and right display units 58L and 58R, and is configured so that as the workload level increases, the center unit lights up in sequence from the left and right ends, making it easy to check the level of workload.

Claims

1. A work vehicle having wheels (2, 3) mounted on a body frame (1), a working device (4), and a control section (5) on which a worker rides, the work vehicle further comprising a first electric motor (30) for driving the working device (4), a second electric motor (40) for driving the front wheels (2), and a battery (50) for supplying power to the first electric motor (30) and the second electric motor (40), the control section (5) being provided with a mode switch (15), and the mode switch (15) being configured to select a mode in which the first electric motor (30) is driven at a power level equal to or lower than a preset level.

2. A work vehicle according to claim 1, wherein the mode switch (15) is configured to select a mode in which the second electric motor (40) is driven at a rotation speed equal to or lower than a preset output rotation speed.

3. A work vehicle according to claim 2, wherein the preset output rotation speed is set to be lower than the rated output rotation speed of the second electric motor (40).

4. A work vehicle according to claim 3, wherein said mode switch (15) is configured to select a mode in which said second electric motor (40) increases in speed at or below a preset angular acceleration.

5. A work vehicle as described in claim 1, wherein when a mode is selected by the mode switch (15), manual operation to increase or decrease the output rotation of the first electric motor (30) and / or increase or decrease the output rotation of the second electric motor (40) is restricted.

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