Work vehicles

Abstract

This system provides a safer work vehicle by reducing the vehicle's speed according to the worker's posture, thereby preventing falls and other accidents. [Solution] A first sensor (26) is provided in the operator's seat (25) of the control unit (5) to measure the seating status of the worker. Below the control unit (5), a first electric motor (30) that drives the harvesting device (4) and a second electric motor (40) that drives the front wheels (2) or rear wheels (3) are provided. The controller (80) of the work vehicle, when the load applied to the first electric motor (30) exceeds the allowable load, and the first sensor (26) measures that a worker is seated in the operator's seat (25), reduces the output rotation of the second electric motor (40) to reduce the travel speed of the work vehicle. If the first sensor (26) does not measure that a worker is seated in the operator's seat (25), the output rotation of the second electric motor (40) is not reduced.

Description

Technical Field

[0001] The present invention relates to a work vehicle for mowing lawn grass.

Background Art

[0002] Conventionally, when the state where an operator boarding the control unit is not seated on the operator's seat continues for a predetermined time, a technique of stopping the automatic running of the work vehicle and stopping the engine is known. (Patent Document 1)

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, with the means of Patent Document 1, there is a risk that an operator who is checking the planting state of lawn grass etc. in a half-sitting or semi-standing posture without sitting on the operator's seat of the control unit may lose their posture and fall, or may hit their body against the steering wheel etc.

[0005] Therefore, the present invention aims to provide a work vehicle with high safety in the working environment by reducing the traveling speed of the work vehicle according to the working posture of the operator and suppressing the operator from falling etc.

Means for Solving the Problems

[0006] The present invention that has solved the above problems is as follows. In other words, the invention described in claim 1 is a work vehicle having a machine frame (1) with a pair of left and right front wheels (2) and rear wheels (3) on the lower side, a mowing device (4) for cutting grass on the front side of the machine frame (1), a control unit (5) for the operator to sit on behind the mowing device (4), and a grass collection container (7) for storing grass behind the control unit (5), The control unit (5) is equipped with a first sensor (26) in the operator's seat (25) for measuring the seating status of an operator. Below the control unit (5) are a first electric motor (30) for driving the harvesting device (4) and a second electric motor (40) for driving the front wheels (2) or rear wheels (3). The controller (80) of the work vehicle is characterized in that, when the load applied to the first electric motor (30) exceeds the allowable load, and the first sensor (26) measures that an operator is seated in the operator's seat (25), it reduces the output rotation of the second electric motor (40) to reduce the travel speed of the work vehicle. If the first sensor (26) does not measure that an operator is seated in the operator's seat (25), it does not reduce the output rotation of the second electric motor (40).

[0007] The invention described in claim 2 is a work vehicle according to claim 1, wherein the operator's seat (25) is provided with a second sensor (29) for measuring the length of the seat belt (27) extended, and the controller (80) reduces the output rotation of the second motor (40) to reduce the travel speed of the work vehicle when the load applied to the first motor (30) exceeds the allowable load, the first sensor (26) measures that an operator is seated in the operator's seat (25), and the second sensor (29) measures that the length of the seat belt (27) extended is less than or equal to a predetermined length, and does not reduce the output rotation of the second motor (40) when the first sensor (26) does not measure that an operator is seated in the operator's seat (25), or when the second sensor (29) measures that the length of the seat belt (27) extended is greater than a predetermined length.

[0008] The invention described in claim 3 is a work vehicle according to claim 2, wherein if the output rotation of the second electric motor (40) is not reduced for a predetermined first set time (J1), the buzzer (25C) of the control unit (5) is activated to issue an alarm.

[0009] The invention described in claim 4 is a work vehicle according to claim 3, wherein a first clutch (55) is provided in the transmission path between the first electric motor (30) and the harvesting work device (4), and the connection of the first clutch (55) is released when the state in which the output rotation of the second electric motor (40) is not reduced has elapsed for a predetermined second setting time (J2) which is longer than the first setting time (J1).

[0010] The invention described in claim 5 is a work vehicle according to claim 4, wherein a blower (17) is provided at the front of a chute (16) connecting the mowing work device (4) and the grass collection container (7), a second clutch (56) is provided in the transmission path between the first electric motor (30) and the blower (17), and the connection of the second clutch (56) is released when the output rotation of the second electric motor (40) is not reduced after a second set time (J2).

[0011] The invention described in claim 6 is a work vehicle according to any one of claims 1 to 5, wherein a brake pedal (11) for braking the rotation of the front wheels (2) and rear wheels (3) is provided on the floor of the control unit (5), and when the brake pedal (11) is pressed down, the rotation of the front wheels (2) and rear wheels (3) is braked. [Effects of the Invention]

[0012] According to the invention described in claim 1, a first sensor (26) for measuring the seating status of an operator is provided in the operator's seat (25) of the control unit (5), a first electric motor (30) for driving the harvesting work device (4) and a second electric motor (40) for driving the front wheel (2) or rear wheel (3) are provided on the lower side of the control unit (5), and the controller (80) of the work vehicle will, if the load applied to the first electric motor (30) exceeds the allowable load, and if the first sensor (26) measures that an operator is seated in the operator's seat (25), the second electric motor (40) will be activated. The output rotation of (0) is reduced to slow down the travel speed of the work vehicle, and if the first sensor (26) does not detect that the worker is seated in the operator's seat (25), the output rotation of the second motor (40) is not reduced. Therefore, if the worker is working in a crouched or semi-standing position without being seated in the operator's seat (25), the controller (80) restricts the reduction of the travel speed of the work vehicle, thereby preventing the worker from losing balance and falling, and improving the safety of the worker's working environment.

[0013] According to the invention described in claim 2, in addition to the effects of the invention described in claim 1, a second sensor (29) for measuring the length of the seat belt (27) is provided in the operator's seat (25). When the load applied to the first motor (30) exceeds the allowable load, if the first sensor (26) measures that an operator is seated in the operator's seat (25) and the second sensor (29) measures that the length of the seat belt (27) is less than or equal to a predetermined length, the controller (80) reduces the output rotation of the second motor (40) to reduce the travel speed of the work vehicle. If the first sensor (26) does not measure that an operator is seated in the operator's seat (25), or if the second sensor (29) measures that the length of the seat belt (27) is greater than the predetermined length, the output rotation of the second motor (40) is not reduced. This further reduces the risk of an operator losing balance and falling, thereby improving the safety of the worker's working environment.

[0014] According to the invention described in claim 3, in addition to the effects of the invention described in claim 2, if the output rotation of the second electric motor (40) is not reduced for a predetermined first set time (J1), the buzzer (25C) of the control unit (5) is activated to sound an alarm, thereby allowing workers who are working in a crouched or semi-standing position to recognize that they are working in an incorrect posture.

[0015] According to the invention described in claim 4, in addition to the effects of the invention described in claim 3, a first clutch (55) is provided in the transmission path between the first electric motor (30) and the harvesting device (4), and if a predetermined second setting time (J2) that is longer than the first setting time (J1) has elapsed without reducing the output rotation of the second electric motor (40), the connection of the first clutch (55) is released, thereby reducing the load applied to the first electric motor (30).

[0016] According to the invention described in claim 5, in addition to the effects of the invention described in claim 4, a blower (17) is provided at the front of the chute (16) that connects the mowing device (4) and the grass collection container (7), a second clutch (56) is provided in the transmission path between the first electric motor (30) and the blower (17), and if the second set time (J2) has elapsed without reducing the output rotation of the second electric motor (40), the connection of the second clutch (56) is released, thereby further reducing the load applied to the first electric motor (30).

[0017] According to the invention described in claim 6, in addition to the effects of the invention described in any one of claims 1 to 5, a brake pedal (11) is provided on the floor of the control unit (5) to brake the rotation of the front wheels (2) and rear wheels (3). When the brake pedal (11) is pressed down, the rotation of the front wheels (2) and rear wheels (3) is braked, so the operator can decelerate the travel speed of the work vehicle by pressing the brake pedal (11) at their own discretion, without relying on the controller (80). [Brief explanation of the drawing]

[0018] [Figure 1] This is a perspective view of the work vehicle from the front left. [Figure 2] It is a perspective view of the operator's seat in the control section as viewed from the front left side. [Figure 3] It is a perspective view of the front part of the electric motor room as viewed from the rear left side. [Figure 4] It is a perspective view of the rear part of the electric motor room as viewed from the rear left side. [Figure 5] It is a perspective view of the electric motor and the gear case as viewed from the front left side. [Figure 6] It is a perspective view of the electric motor and the gear case as viewed from the rear left side. [Figure 7] It is a rear view of the electric motor and the gear case. [Figure 8] It is a sectional view of the broken left part of the gear case. [Figure 9] It is a transmission diagram of the output rotation of the electric motor. [Figure 10] It is a perspective view of the battery as viewed from the rear left side. [Figure 11] It is a plan view of the battery placed in the electric motor room. [Figure 12] It is a plan view of the electric motor and the inverter device. [Figure 13] It is a left side view of the electric motor and the inverter device. [Figure 14] It is a left side view of the electric motor room. [Figure 15] It is a perspective view of the electric motor room as viewed from the rear right side. [Figure 16] It is a connection diagram of the controller. [Figure 17] It is an explanatory diagram of load control. [Figure 18] It is an explanatory diagram of the power line and the signal line connecting the controller and the electric motor. [Figure 19] It is an explanatory diagram of the method for maintaining and stopping load control

Modes for Carrying Out the Invention

[0019] As shown in FIG. 1, the work vehicle is provided with a pair of left and right front wheels 2 at the front part under the machine body frame 1, and a pair of left and right rear wheels 3 at the rear part under the machine body frame 1.

[0020] The front of the machine frame 1 is equipped with a mowing device 4 for cutting grass growing in the field, and the rear of the mowing device 4 is equipped with a control unit 5 where the operator sits. Behind the control unit 5 is a safety frame (rops) 6 for protecting the operator, and behind the safety frame 6 is equipped with a grass collection container 7 for storing the cut grass. Below the grass collection container 7 is an electric motor room 8 where the electric motor 30 and battery 60 for driving the mowing device 4 are located.

[0021] A steering column 10 supporting the steering wheel is provided in front of the operator's seat 25 of the control unit 5. A touch panel monitor that displays the output rotation speed of the electric motor 30 and other information is provided at the top of the steering column 10, and the lower part is fixed to the front of the floor.

[0022] A brake pedal 11 for reducing the rotational speed of the front wheels 2 is provided on the left side of the steering column 10 on the floor, and an accelerator pedal 12 for increasing or decreasing the output rotational speed of the electric motor 40 that drives the front wheels 2 is provided on the right side. The amount of depression of the brake pedal 11 and the accelerator pedal 12 is measured by angle sensors 11S and 12S, such as potentiometers, mounted on their bases, respectively.

[0023] The area above the front wheel 2 is covered by a fender 13, and the fender 13, located to the right of the operator's seat 25, is provided with a gear shift lever 14 for operating an inverter device 35 that increases or decreases the output rotation of the electric motor (the "first electric motor" in the claim) 30.

[0024] Furthermore, behind the gear shift lever 14, there is an operating switch 15 that activates load control, which reduces the output rotation of the motor for driving (the "second motor" in the claim) 40 to a predetermined range when the load applied to the motor for work exceeds a predetermined level.

[0025] The rear of the mowing device 4 and the front of the grass collection container 7 are connected by a chute 16 that extends in the front-to-back direction, and a blower 17 is provided in the middle of the chute 16 in the front-to-back direction to exhaust air into the chute 16.

[0026] A pair of link arms 18 are provided on the front of the left and right walls of the grass collection container 7. The front of each link arm 18 is pivotably fixed to the safety frame 6, and the safety frame 6 and the link arms 18 are connected by a lifting component 19 such as a hydraulic cylinder. The rear of the lower wall of the grass collection container 7 is resting on the horizontal frame 21A of the support frame 21, which will be described later. This allows the lifting component 19 to be driven to raise and lower the grass collection container 7.

[0027] As shown in Figure 2, a weight sensor (the "first sensor" in the claim) 26 for measuring the operator's weight is provided in the center of the seat cushion 25A of the control unit 5, an attachment sensor 28 for detecting whether or not the seat belt 27 is attached is provided on the left rear of the seat cushion 25A, and a length sensor (the "second sensor" in the claim) 29 for measuring the length of the seat belt 27 is provided on the right rear of the seat cushion 25A. This makes it possible to detect whether the operator is operating the mowing device 4 or the grass in front of the mowing device 4 in a crouched or semi-standing position without sitting in the control unit 25. When the operator is in a crouched or semi-standing position, the measurement value of the weight sensor 26 becomes smaller than a predetermined value, and the measurement value of the length sensor 29 becomes larger than a predetermined value. In addition, a buzzer that sounds an alarm in case of abnormality is provided on the right side of the backrest seat cushion 25B of the control unit 25.

[0028] As shown in Figures 3 and 4, the front motor room 8A of the motor room 8 is equipped with motors 30 and 40, and the rear motor room 8B is equipped with a battery 60 for storing power supplied to motors 30 and the like.

[0029] In a plan view, the electric motor 30 is located to the left of the left-right centerline of the aircraft frame 1, and the electric motor 40 is located to the right of the left-right centerline of the aircraft frame 1. This allows for... By suppressing the weight difference between the weight applied to the left of the aircraft frame 1's lateral centerline and the weight applied to the right of the aircraft frame 1's lateral centerline, steering performance can be improved.

[0030] In a side view, a support frame 20 extending upward from the aircraft frame 1 is provided in the partition between the front motor compartment 8A and the rear motor compartment 8B, and a support frame 21 extending upward from the aircraft frame 1 is provided at the rear end of the rear motor compartment 8B.

[0031] The support frame 20 is formed by a left vertical frame 20L extending upward from the middle left portion of the aircraft frame 1, a right vertical frame 20R extending upward from the middle right portion of the aircraft frame 1, and a horizontal frame 20A extending in the left-right direction that connects the upper parts of the left vertical frame 20L and the right vertical frame 20R.

[0032] The support frame 21 is formed by a left longitudinal frame 21L extending upward from the left rear end of the aircraft frame 1, a right longitudinal frame 21R extending upward from the right rear end of the aircraft frame 1, a transverse frame 21A extending in the left-right direction and connecting the upper parts of the left longitudinal frame 21L and the right longitudinal frame 21R, and a transverse frame 21B extending in the left-right direction and connecting the intermediate parts of the left longitudinal frame 21L and the right longitudinal frame 21R. The left part of the transverse frame 21B extends to the left of the left longitudinal frame 21L, and the right part extends to the right of the right longitudinal frame 21R.

[0033] The middle section of the left vertical frame 20L and the left end of the horizontal frame 21B are connected by the left front-rear frame 22L, which extends in the front-rear direction, and the middle section of the right vertical frame 20R and the right end of the horizontal frame 21B are connected by the right front-rear frame 22R, which extends in the front-rear direction. This allows the rear of the battery 60 to be positioned above the drive shaft 44 of the rear wheel 3, preventing large deformations from occurring in the aircraft frame 1.

[0034] The upper part of the left vertical frame 20L and the middle part of the left vertical frame 23L located at the rear of the control unit 5 are connected by a left front-rear frame 24L that extends in the front-rear 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 located at the rear of the control unit 5 are connected by a right front-rear frame 24R that extends in the front-rear direction.

[0035] As shown in Figures 5 and 6, the motor 30 and motor 40 are in front of the motor 30 and motor 40. It is connected to a gear case 50 located on the side. The output rotation of the electric motor 30 is accelerated and decelerated within the gear case 50 before being transmitted to the output shaft 31 to which the harvesting work device 4 etc. is connected, the output shaft 32 to which the blower 17 etc. is connected, and the output shaft 33 to which the hydraulic pump 51 etc. is connected. The output rotation of the electric motor 40 is accelerated and decelerated within the gear case 50 before being transmitted to the output shaft 41 to which the front wheels 2 etc. are connected, and to the output shaft 42 to which auxiliary work equipment etc. is connected.

[0036] Output shaft 31 extends forward from the left middle of the gear case 50 in the front-rear direction, and the front of output shaft 31 is connected to the harvesting device 4. Output shaft 32 extends forward from the front of the gear case 50, and the front of output shaft 32 is connected to the blower 17. Output shaft 33 extends rearward from the rear of the gear case 50, and a hydraulic pump 51 is connected to the rear of output shaft 33. A valve 52 is also provided on the upper part of the gear case 50.

[0037] Output shafts 41 and 42 extend in the front-rear direction along the right side of the gear case 50. The output rotation of output shaft 41 is transmitted to drive shaft 43 via differential gear 54 located inside the gear case 50. An insertion hole 50A extending in the left-right direction is provided in the middle of the gear case 50 in the front-rear direction, through which drive shaft 43 is inserted. Output shaft 42 extends rearward from the rear of the gear case 50.

[0038] The length of the electric motor 30 in the front-to-back direction is longer than the length of the electric motor 40 in the front-to-back direction. This allows for smooth driving of the harvesting work device 4, which is constantly driven and subjected to a large load.

[0039] As shown in Figure 7, the hydraulic pump 51 is positioned below the electric motors 30 and 40. This prevents air from entering the hydraulic pump 51 and suppresses air lock. In addition, the flexible piping 53A connecting the hydraulic pump 51 and the valve 52 is routed between the electric motors 30 and 40. This allows for effective use of the space formed between the electric motors 30 and 40.

[0040] As shown in Figure 8, the oil supplied to the valve 52 is supplied via the valve 52 to a clutch (the "first clutch" in the claim) 55 located upstream of the transmission path of the output shaft 31 in the gear case 50, and to a clutch (the "second clutch" in the claim) 56 located upstream of the transmission path of the output shaft 32. This allows the valve 52 to be driven to connect and disconnect the clutch 55 and the clutch 56.

[0041] The oil supplied from clutches 55 and 56 to valve 52 is returned to the gear case 50 through a flexible pipe 53B and a circulation port 50B formed at the top of the gear case 50. This allows the amount of oil in the gear case 50 to be maintained at a predetermined level.

[0042] As shown in Figure 9, the output rotation of the electric motor 30 is transmitted to the input shaft 57A of the gear case 50, the output rotation of the input shaft 57A is accelerated or decelerated before being transmitted to the output shaft 33, and the output rotation of the output shaft 33 is transmitted to the hydraulic pump 51. This allows the electric motor 30 to be driven to drive the hydraulic pump 51. In addition, the output rotation of the input shaft 57A is accelerated or decelerated before being transmitted to the rotating shaft 58A.

[0043] The output rotation of the rotating shaft 58A is transmitted to the rotating shaft 58B, and the output rotation of the rotating shaft 58B is transmitted to the output shaft 31 via the clutch 55. The output rotation of the output shaft 31 is transmitted to the harvesting device 4. This allows the electric motor 30 to be driven, which in turn drives the harvesting device 4.

[0044] The output rotation of the input shaft 57A is transmitted to the rotating shaft 58C, and the output rotation of the rotating shaft 58C is transmitted to the output shaft 32 via the clutch 56. The output rotation of the output shaft 32 is transmitted to the blower 17. This allows the electric motor 30 to be driven, which in turn drives the blower 17.

[0045] The output rotation of the electric motor 40 is transmitted to the input shaft 57B of the gear case 50, and the output rotation of the input shaft 57B is accelerated or decelerated before being transmitted to the output shafts 41 and 42.

[0046] The output rotation of the output shaft 41 is transmitted to the drive shaft 43 for the front wheels via the differential gear 54, and the output rotation of the drive shaft 43 is transmitted to the front wheels 2. This allows the electric motor 40 to be driven and the front wheels 2 to rotate. In addition, a braking booster 48 for the front wheels is provided to brake the rotation of the front wheels 2.

[0047] The output rotation of the output shaft 42 is transmitted to the drive shaft 44 for the rear wheels via the clutch 47 and differential gear 59 for 4WD, and the output rotation of the drive shaft 44 is transmitted to the rear wheels 3. This allows the electric motor 40 to be driven and the rear wheels 3 to rotate. In addition, a braking booster 49 for the rear wheels is provided to brake the rotation of the rear wheels 3.

[0048] As shown in Figure 10, the battery 60 is formed from four battery modules 60A. The upper parts of the four battery modules 60A are connected by a pair of left and right angle-shaped mounting frames 61 that extend in the front-to-back direction and are spaced apart in the left-to-right direction, and the lower parts are connected by a pair of left and right square pipe-shaped mounting frames 62 that extend in the front-to-back direction and are spaced apart in the left-to-right direction.

[0049] The front portion of the mounting frame 61 extends forward of the battery 60, and the rear portion extends backward of the battery 60. The mounting frame 62 extends from the front end to the rear end of the battery 60.

[0050] As shown in Figure 11, the front part of the mounting frame 61 is detachably fixed to the horizontal frame 20A of the support frame 20 by fastening members such as bolts, and the rear part is detachably fixed to the horizontal frame 21A of the support frame 21 by fastening members such as bolts.

[0051] The left mounting frame 62 is mounted on the left front / rear frame 22L, and the right mounting frame 62 is mounted on the right front / rear frame 22R.

[0052] The front and rear of the mounting frame 61 are formed with openings 61A through which a suspension hook can be inserted when replacing the battery 60. This allows the battery 60 to be easily attached to and detached from the support frame 20 and support frame 21, and the battery 60 to be easily replaced.

[0053] A radiator 65 for cooling the water used to cool the electric motor 30 and the like is provided on the outside of the left wall of the motor room 8, and a fan 66 for blowing outside air towards the motor room 8 is provided between the radiator 65 and the electric motor 30. In addition, a circular opening (not shown) is formed on the left wall of the motor room 8 in the area opposite the fan 66. This helps to suppress the temperature rise of the electric motor 30 and the like, and prevents the electric motor 30 and the like from malfunctioning.

[0054] An auxiliary battery 67 is provided on the outside of the right wall of the power room 8, opposite the radiator 65, to store power supplied to the monitor of the control unit 5. This helps to suppress the weight difference between the left and right sides of the work vehicle.

[0055] As shown in Figures 12 and 13, an inverter device 35 that drives the motor 30 is provided on the rear side of the motor 30 at a predetermined distance in the front-rear direction, and an inverter device 45 that drives the motor 40 is provided on the rear side of the motor 40 at a predetermined distance in the front-rear direction. Furthermore, the inverter devices 35 and 45 are provided on the front side of the battery 60 at a predetermined distance in the front-rear direction. This makes it easy to arrange the motors 30 and 40 and the inverter devices 35 and 45. In addition, the air blown from the fan 66 can pass through the gap between the motors 30 and 40 and the inverter devices 35 and 45, allowing for efficient cooling of the motors 30 and 40 and the inverter devices 35 and 45.

[0056] As shown in Figures 14 and 15, a power receiving port 70 for receiving power from a household power supply is provided on the upper rear side of the radiator 65.

[0057] An electrical unit 71 is located beneath the battery 60. The electrical unit 71 contains a charger that converts the power supplied to the power receiving port 70 from AC to DC and supplies it to the battery 60, and a converter that steps down the DC voltage supplied via the power distribution unit 73, etc., to the rated voltage of the auxiliary battery 67. The electrical unit 71 is detachably fixed to the underside of the left front and rear frame 22L and the right front and rear frame 22R.

[0058] A monitoring unit 72, which houses a monitoring device for monitoring the temperature and voltage of the battery 60, is provided on the front side of the battery 60. The monitoring unit 72 is detachably fixed to the upper part of the left front and rear frame 24L and the right front and rear frame 24R.

[0059] In a side view, it is preferable that the upper wall of the monitoring unit 72 be positioned below the mounting frame 61. This prevents the monitoring unit 72 from protruding above the mounting frame 61, allowing the height of the motor room 8 to be lower. As a result, the center of gravity of the grass collection container 7, which is located above the motor room 8, can be set at a lower position, allowing the work vehicle to run stably.

[0060] Below the monitoring unit 72, there is a power distribution unit 73 which houses terminal blocks for distributing the power supplied from the monitoring unit 72 to inverter devices 35 and 45, and converters of the electrical equipment unit 71, etc. The power distribution unit 73 is detachably fixed to the underside of the left front and rear frame 24L and the right front and rear frame 24R.

[0061] As shown in Figure 16, the controller 80 of the work vehicle is formed from a processing unit 81 consisting of a CPU and the like, a storage unit 82 consisting of ROM, RAM, a hard disk drive, flash memory and the like, and a communication unit 84 for data communication with the outside.

[0062] The processing unit 81 performs functions such as driving the braking system based on the amount the brake pedal 11 is pressed, calculating output values ​​to be output to the inverter device 45 based on the amount the accelerator pedal 12 is pressed, and calculating output values ​​to be output to the inverter device 35 based on the amount the gear shift lever 14 is operated.

[0063] The memory unit 82 stores preset permissible loads that the electric motor 30 can handle, load control algorithms, and the like.

[0064] The communication unit 84 transmits and receives data with a portable controller (not shown).

[0065] The input side of the controller 80 is connected via a predetermined input interface circuit to an angle sensor 11S for measuring the amount of depression of the brake pedal 11, an angle sensor 12S for measuring the amount of depression of the accelerator pedal 12, an operation switch 15 that activates load control to reduce the load on the work motor 30 by reducing the output rotation of the drive motor 40 when the load on the work motor 30 exceeds a predetermined level, a weight sensor 26 for measuring the weight of the worker applied to the seat cushion 25A, an attachment sensor 28 for detecting whether or not the seat belt 27 is attached, a length sensor 29 for measuring the length of the seat belt 27, and an inverter device 35, etc.

[0066] The output side of the controller 80 is connected via a predetermined output interface circuit to a buzzer 25C that sounds an alarm in case of abnormality, an inverter device 35 that drives the electric motor 30 for work, an inverter device 45 that drives the electric motor 40 for travel, a braking booster 48 that brakes the rotation of the front wheels 2, a braking booster 49 that brakes the rotation of the rear wheels 3, a clutch 55 provided on the upstream side of the transmission path of the harvesting work device 4, and a clutch 56 provided on the upstream side of the transmission path of the blower 17.

[0067] As shown in Figure 17, load control is performed such that when the load applied to the motor 30 is less than or equal to the allowable load, the output rotation of the motor 40 is increased or decreased based on the amount the accelerator pedal 12 is pressed, and when the load applied to the motor 30 exceeds the allowable load, the output rotation of the motor 40 is reduced. This reduces the amount of grass cut by the mowing device 4 and thus reduces the load applied to the motor 30. The reduction in the output rotation of the motor 40 can be performed along a straight first reduction line L1, a stepped second reduction line L2, and a curved third reduction line L3.

[0068] As shown in Figure 18, power from the battery 60 is supplied to the controller 80 via power line P1, to the inverter devices 35 and 45 via power line P2, and to the electric motors 30 and 40 via power line P3.

[0069] The output value of the controller 80 is input to the inverter device 35 via signal line T1, and the output value of the inverter device 35 is input to the motor 30 via signal line T2. In addition, information such as the load applied to the motor 30 is input to the inverter device 35 via signal line T2, and input from the inverter device 35 to the controller 80 via signal line T1.

[0070] The output value of the controller 80 is input to the inverter device 45 via signal line T3, and the output value of the inverter device 45 is input to the electric motor 40 via signal line T4. In addition, information such as the load applied to the electric motor 40 is input to the inverter device 45 via signal line T4, and input from the inverter device 45 to the controller 80 via signal line T3. As a result, the operator can accurately predict the working time and travel distance that the electric motors 30 and 40 can use to harvest using the power of the battery 60 for each mode 1 to 3, and can efficiently plan the harvesting procedure.

[0071] As shown in Figure 19, at the start, the operator has pressed the activation switch 15 to perform load control, the operator is seated firmly in the operator's seat 25 and wearing the seat belt 27, the weight sensor 26 has measured a value of a weight greater than or equal to a predetermined weight, the attachment sensor 28 has detected that the seat belt 27 is attached, and the length sensor 29 has measured a value of a length less than or equal to a predetermined length.

[0072] In step S1, the processing unit 81 of the controller 80 determines whether the load applied to the electric motor 30 that drives the harvesting device 4 and the blower 17 is less than or equal to a preset allowable load. If the signal input from the inverter device 35 to the controller 80 indicates that the load applied to the electric motor 30 exceeds the preset allowable load, the process proceeds to step S2. If the feedback signal indicates that the load applied to the electric motor 30 is less than or equal to the preset allowable load, the process proceeds to step S5.

[0073] In step S2, the processing unit 81 determines whether the worker is properly seated in the operating seat 25. If the measured value input from the weight sensor 26 to the controller 80 exceeds a preset weight, for example, about 80% of the worker's body weight, the unit determines that the worker is properly seated in the operating seat 25 and proceeds to step S3. If the measured value is less than or equal to the preset weight, the unit determines that the worker is in a crouched or semi-standing position and proceeds to step S6.

[0074] In step S3, the processing unit 81 determines whether the worker is wearing the seat belt 27. If the signal input from the fitting sensor 28 to the controller 80 detects a locked state and is ON, it is determined that the worker is wearing the seat belt 27 and the process proceeds to step S4. If the signal does not detect a locked state and is OFF, it is determined that the worker is not wearing the seat belt 27 and the process proceeds to step S6.

[0075] In step S4, the processing unit 81 determines whether the worker is properly seated in the operating seat 25. If the measured length of the seat belt 27, input from the length sensor 29 to the controller 80, is less than or equal to a preset length, the processing unit determines that the worker is properly seated in the operating seat 25 and proceeds to step S5. If the measured length exceeds the preset length, the processing unit determines that the worker is in a crouched or semi-standing position and proceeds to step S6. This allows for a more accurate determination of the worker's operating posture, i.e., whether the worker is properly seated in the operating seat 25 or in a crouched or semi-standing position.

[0076] In step S5, the processing unit 81 maintains load control, and if the load applied to the work motor 30 exceeds the allowable load, it reduces the output rotation of the drive motor 40 via the inverter device 45 to reduce the load applied to the motor 30 and terminates the series of operations. Even while load control is being performed, the operator can depress the brake pedal 11 to decelerate the rotation of the front wheels 2 and rear wheels 3 via the brake boosters 48 and 49, or operate the accelerator pedal 12 to increase or decrease the output rotation of the motor 40 to increase or decrease the travel speed of the work vehicle.

[0077] In step S6, the processing unit 81 stops load control and proceeds to step S7. This prevents workers from losing their balance and falling over due to the deceleration of the work vehicle while working in a crouched or semi-standing position. Even when load control is stopped, the worker can decelerate the rotation of the front wheels 2 and rear wheels 3 via the brake boosters 48 and 49 by pressing the brake pedal 11, or increase or decrease the output rotation of the electric motor 40 to increase or decrease the travel speed of the work vehicle by operating the accelerator pedal 12.

[0078] In step S7, the processing unit 81 starts the timer 83 and proceeds to step S8.

[0079] In step S8, the processing unit 81 determines the duration for which a load greater than the allowable load of the electric motor 30 is applied to the electric motor 30. If the duration for which a load greater than the allowable load is applied to the electric motor 30 is longer than a preset first setting time J1, the process proceeds to step S9; otherwise, it returns to step S7.

[0080] In step S9, the processing unit 81 activates the buzzer 25C to alert the worker and proceed to step S10. This prompts the worker, who is working in a crouched position, to stop working and sit in the operator's seat 25.

[0081] In step S10, the processing unit 81 determines the duration for which a load greater than the allowable load of the electric motor 30 is applied to the electric motor 30. If the duration for which a load greater than the allowable load is applied to the electric motor 30 is longer than a preset second setting time J2, the process proceeds to step S11; otherwise, the process returns to step S7.

[0082] In step S11, the processing unit 81 disengages the clutch 55 located in the transmission path between the electric motor 30 and the harvesting device 4, and proceeds to step S12. This stops the drive of the harvesting device 4, reducing the load on the electric motor 30 that exceeds the allowable load.

[0083] In step S12, the processing unit 81 terminates the series of operations by disengaging the clutch 56 provided in the transmission path between the electric motor 30 and the blower 17. This stops the blower 17 from running, further reducing the load on the electric motor 30 that is greater than the allowable load. [Explanation of Symbols]

[0084] 1. Aircraft frame 2 Front wheels 3 Rear wheels 4 Reaping device 5. Control Unit 7 Grass collection container 11 Brake pedal 16 Shooter 17 Blower 25 Control seat 25C Buzzer 26. Weight sensor (first sensor) 27 Seat belts 29. Length sensor (second sensor) 30 Electric motor (1st electric motor) 40 Electric motor (second electric motor) 55 Clutch (First Clutch) 56 Clutch (Second Clutch) 80 Controllers J1 First set time J2 Second Schedule

Claims

1. In a work vehicle having a frame (1) with a pair of front wheels (2) and rear wheels (3) on the underside, a grass cutting device (4) for cutting grass on the front of the frame (1), a control unit (5) for the operator to sit on behind the grass cutting device (4), and a grass collection container (7) for storing grass behind the control unit (5), A first sensor (26) is provided in the operator's seat (25) of the control unit (5) to measure the seating position of the worker. Below the control unit (5), a first electric motor (30) for driving the harvesting device (4) and a second electric motor (40) for driving the front wheel (2) or rear wheel (3) are provided. The controller (80) of the work vehicle is characterized in that, when the load applied to the first electric motor (30) exceeds the allowable load, if the first sensor (26) measures that an operator is seated in the operator's seat (25), it reduces the output rotation of the second electric motor (40) to reduce the travel speed of the work vehicle, and if the first sensor (26) does not measure that an operator is seated in the operator's seat (25), it does not reduce the output rotation of the second electric motor (40).

2. A second sensor (29) for measuring the length of the seat belt (27) is provided in the operator's seat (25). The controller (80) reduces the output rotation of the second motor (40) to reduce the travel speed of the work vehicle when the load applied to the first motor (30) exceeds the allowable load, the first sensor (26) measures that an operator is seated in the operator's seat (25), and the second sensor (29) measures that the length of the seat belt (27) is less than or equal to a predetermined length, and the controller (80) does not reduce the output rotation of the second motor (40) when the load applied to the first motor (30) exceeds the allowable load, and the first sensor (26) measures that an operator is seated in the operator's seat (25), and the second sensor (29) measures that the length of the seat belt (27) is greater than a predetermined length. The work vehicle according to claim 1.

3. The work vehicle according to claim 2, wherein if the output rotation of the second electric motor (40) is not reduced for a predetermined first set time (J1) has elapsed, the buzzer (25C) of the control unit (5) is activated to sound an alarm.

4. A first clutch (55) is provided in the transmission path between the first electric motor (30) and the harvesting device (4). The work vehicle according to claim 3, wherein if the output rotation of the second electric motor (40) is not reduced for a predetermined second setting time (J2) which is longer than the first setting time (J1), the connection of the first clutch (55) is released.

5. A blower (17) is provided at the front of the chute (16) that connects the mowing device (4) and the grass collection container (7). A second clutch (56) is provided in the transmission path between the first electric motor (30) and the blower (17). The work vehicle according to claim 4, wherein the second clutch (56) is released if the output rotation of the second electric motor (40) is not reduced after a second set time (J2).

6. A work vehicle according to any one of claims 1 to 5, wherein a brake pedal (11) for braking the rotation of the front wheels (2) and rear wheels (3) is provided on the floor of the control unit (5), and when the brake pedal (11) is pressed, the rotation of the front wheels (2) and rear wheels (3) is braked.

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