Work vehicle

Abstract

To provide a work vehicle in which foot parts in a driver's seat are simplified and which can prevent an operator from operating erroneously.SOLUTION: A work vehicle according to one embodiment is provided with a position measurement device, left and right front wheels and left and right rear wheels of the vehicle, left and right brake gears, brake pedals, a brake sensor, a left / right individual brake selecting part, and a running control part. When a position of the vehicle recognized by the position measurement device is at a position in a farm field in farm-field data and step-on of the brake pedal is sensed by the brake sensor, the running control part performs one-side braking for making one of the left and right brake devices operate so that braking is applied to one of the left and right rear wheels selected by a left / right individual braking switch.SELECTED DRAWING: Figure 6

Description

Technical Field

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

Background Art

[0002] Conventionally, there is known a work vehicle that travels under automatic control of a controller while recognizing the position of the vehicle body on a map using positioning information from GPS satellites (see, for example, Patent Document 1). The work vehicle is provided with a brake linkage that integrally connects left and right brake pedals for braking control of the left and right rear wheels respectively. The work vehicle includes a brake control device that operates the brake linkage and integrally connects the left and right brake pedals when an image analysis unit determines that the monitoring area is a road.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In work in a field, a work vehicle may perform left and right sharp turns by operating the left and right brakes respectively. The conventional technology was configured such that when the work vehicle makes a sharp turn, the operator needs to distinguish between pressing the brake pedal in the turning direction. Therefore, there was a risk of operation errors when the operator distinguishes between pressing the left and right brake pedals at the foot area of the driver's seat.

[0005] The present invention has been made in view of the above, and an object thereof is to simplify the foot area of the driver's seat and prevent operation errors of the operator.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a positioning device (30) for recognizing the position of the vehicle body, the left and right front wheels (4) and the left and right rear wheels (5) of the vehicle body, left and right brake devices (312) for braking the left and right rear wheels (5) respectively, a brake pedal (13) for operating the left and right brake devices (312), a brake sensor (50) for detecting depression of the brake pedal (13), a left / right differential braking selection unit (20) for selecting which of the left and right rear wheels (5) to apply the brake to, and a travel control unit (42) that controls an actuator (311) for operating the left and right brake devices (312) and has field data including the position and shape of the field. When the position of the vehicle body recognized by the positioning device (30) is within the field position in the field data and the depression of the brake pedal (13) is detected by the brake sensor (50), the travel control unit (42) performs single braking to operate one of the left and right brake devices (312) so as to apply the brake to either one of the left and right rear wheels (5) selected by the left / right differential braking selection unit (20).

Effect of the Invention

[0007] According to the work vehicle according to the embodiment, the foot area of the driver's seat can be simplified, and operator operation errors can be prevented.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the work vehicle disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by the embodiments shown below.

[0010] <First Embodiment> First, the overall configuration of the work vehicle according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic left side view of the work vehicle according to the present embodiment. FIG. 2 is a schematic perspective view of the front of the driver's seat of the work vehicle according to the embodiment. FIG. 3 is a schematic right side view of the brake pedal of the work vehicle according to the embodiment. In the present embodiment, the tractor 1 will be described as an example of the work vehicle.

[0011] The tractor 1, which is a work vehicle, is an agricultural tractor that performs work in a field or the like while self-propelling. Further, the operator boards the tractor 1 and executes predetermined work while traveling in the field.

[0012] In the present embodiment, the front-rear direction is the traveling direction when the tractor 1 is going straight, and the front side in the traveling direction is defined as "front" and the rear side as "rear". The traveling direction of the tractor 1 is the direction from the driver's seat 8 described later toward the steering wheel 9 when going straight.

[0013] The left - right direction is a direction that is horizontally orthogonal to the front - rear direction. Hereinafter, the left and right are defined with respect to the "front" side. That is, in the state where the operator of the tractor 1 is seated in the driver's seat 8 and facing forward, the left - hand side is "left" and the right - hand side is "right".

[0014] The up - down direction is a direction parallel to the vertical direction. The front - rear direction, the left - right direction, and the up - down direction are mutually orthogonal. Note that each direction is defined for the convenience of explanation, and the present invention is not limited by these directions. Also, in this embodiment, the tractor 1 may be referred to as the "airframe" in some cases.

[0015] As shown in FIG. 1, the tractor 1 includes a traveling vehicle body 2 and a working machine W. The traveling vehicle body 2 includes a vehicle body frame 3, left and right front wheels 4, left and right rear wheels 5, a bonnet 6, an engine E, a control unit 7, and a transmission case 10. The vehicle body frame 3 is the main frame of the traveling vehicle body 2.

[0016] The left and right front wheels 4 are a pair on the left and right, and mainly serve as steering wheels (steering wheels). The left and right rear wheels 5 are a pair on the left and right, and mainly serve as driving wheels (drive wheels). The tractor 1 may be configured to be able to switch between two - wheel drive (2WD) in which the left and right rear wheels 5 drive and four - wheel drive (4WD) in which both the left and right front wheels 4 and the left and right rear wheels 5 drive. In this case, the drive wheels are both the left and right front wheels 4 and the left and right rear wheels 5. Note that the traveling vehicle body 2 may be provided with a crawler device instead of the wheels (left and right front wheels 4 and left and right rear wheels 5). In this case, the traveling crawler is the drive wheel.

[0017] The bonnet 6 is provided at the front part of the traveling vehicle body 2 so as to be openable and closable. The bonnet 6 is rotatable (openable and closable) in the up - down direction with the rear part as the rotation center. The bonnet 6 covers the engine E mounted on the vehicle body frame 3 in the closed state. The engine E is the drive source of the tractor 1 and is a heat engine such as a diesel engine or a gasoline engine.

[0018] The control unit 7 is provided on the upper part of the traveling vehicle body 2 and includes a driver's seat 8, a steering wheel 9, etc. The control unit 7 may be formed by being covered with a cabin 7a provided on the upper part of the traveling vehicle body 2. The driver's seat 8 is the seat for the operator. The steering wheel 9 is operated by the operator when steering the traveling direction of the left and right front wheels 4 which are the steering wheels.

[0019] As shown in FIG. 2, the control unit 7 is provided with various operation pedals such as a clutch pedal 28 and a brake pedal 13 in addition to the steering wheel 9 and the meter panel 27. In the vicinity of the steering wheel 9, various operation levers are provided, such as a forward and reverse lever 29 for operating the forward and reverse movement of the traveling vehicle body 2 and a turn signal lever 31 for operating the left and right turn signals 14 (see FIG. 1).

[0020] On the spoke portion 9a of the steering wheel 9, a left and right independent braking selection switch 33 which is a left and right independent braking selection unit 20 (see FIG. 5) is provided. The left and right independent braking selection switch 33 selects which brake of the left and right rear wheels 5 to apply. The left and right independent braking selection switch 33 is, for example, a right switch and a left switch, and is provided within the reach of the operator's finger while the operator is gripping the steering wheel 9. Thereby, the left and right independent braking selection switch 33 is configured such that the operator can press the right switch or the left switch while operating the steering wheel 9.

[0021] Also, a camera 32 is provided in the vicinity of the meter panel 27. The camera 32 is, for example, a CCD camera, and the shooting direction is directed at the eyes of the operator sitting on the driver's seat 8. Thereby, the camera 32 can shoot an image including the eyes of the operator.

[0022] As shown in FIG. 3, the brake pedal 13 is configured such that the claw 50a of the brake sensor 50 rotates by a pin 13p attached to the arm of the brake pedal 13. The brake sensor 50 can detect the depression of the brake pedal 13 by the operator by detecting the angle through which the claw 50a of the brake sensor 50 rotates.

[0023] Returning to FIG. 1, the transmission case 10 houses a transmission (speed-changing mechanism). The transmission appropriately reduces the power (rotational power) transmitted from the engine E and transmits it to the left and right rear wheels 5, which are drive wheels, and to the PTO (Power Take-off) shaft.

[0024] At the rear of the traveling vehicle body 2, a working machine W for performing work in the field is mounted, and a PTO shaft for transmitting the power for driving the working machine W protrudes rearward from the transmission case 10. The PTO shaft transmits the rotational power appropriately reduced by the transmission to the working machine W mounted at least on the rear part of the traveling vehicle body 2.

[0025] Also, at the rear of the traveling vehicle body 2, a lifting device 12 for raising and lowering the working machine W is provided. The lifting device 12 moves the working machine W to a non-working position by raising the working machine W. The non-working position is, for example, the position where the working machine W is raised when the traveling vehicle body 2 reverses or when the traveling vehicle body 2 turns. Also, the lifting device 12 moves the working machine W to a ground-working position by lowering the working machine W. The lifting device 12 includes a hydraulic main cylinder 121 for raising and lowering the lifting device 12, a lift arm 122, a lift rod 123, a lower link 124, and a top link 125.

[0026] When hydraulic oil is supplied to the main cylinder 121, the lift arm 122 rotates about the axis AX serving as a pivot point to raise the working machine W, and when the hydraulic oil is discharged from the main cylinder 121, it rotates about the axis AX to lower the working machine W. Note that a lift arm sensor 25 for detecting the rotation angle of the lift arm 122 is provided at the base of the lift arm 122 (near the axis AX). The lifting position of the working machine W is calculated based on the detection result of the lift arm sensor 25 and the working machine W.

[0027] Further, the lift arm 122 is connected to the lower link 124 via a lift rod 123. In this way, the lifting device 12 connects the working machine W to the traveling vehicle body 2 via the lower link 124 and the top link 125 so that the working machine W can be lifted and lowered.

[0028] The working machine W is a machine for performing work in the field. In the example shown in FIG. 1, the working machine W is a rotary tiller for performing tilling work in the field. The rotary tiller tills the field surface by rotating the tilling claws 61 by the power transmitted from the PTO shaft.

[0029] Further, the tractor 1 includes a control device 40 (see FIG. 5). The control device 40 controls the engine E and also controls the traveling speed of the traveling vehicle body 2. Further, the control device 40 controls the working machine W.

[0030] Further, the tractor 1 includes a positioning device 30. The positioning device 30 is provided on the upper part of the traveling vehicle body 2 and measures the body position (latitude and longitude) which is the position of the traveling vehicle body 2. The positioning device 30 is, for example, a GNSS (Global Navigation Satellite System), and can perform positioning and timekeeping by receiving radio waves from the navigation satellite S orbiting in the sky.

[0031] Next, the traveling vehicle body 2 of the tractor 1 will be described with reference to FIG. 4. FIG. 4 is an explanatory view of the traveling vehicle body 2 of the tractor 1.

[0032] In the following, the left side will be indicated by the symbol L and the right side by the symbol R. However, when there is no need to distinguish between the left and right sides, it may be described as, for example, the left and right front wheels 4 and the left and right rear wheels 5.

[0033] As shown in FIG. 4, the tractor 1 includes left and right front wheels 4L and 4R attached to left and right front axles 406L and 406R, respectively, on the left and right sides of the machine body, and left and right rear wheels 5L and 5R attached to left and right rear axles 405L and 405R.

[0034] An engine E is mounted at the front of the machine body, and power is transmitted from the engine E to the left and right front wheels 4 and the left and right rear wheels 5 via a power transmission mechanism. The tractor 1 according to the present embodiment includes a 4WD clutch 324, and by switching this 4WD clutch 324, it is configured to be switchable between a 2WD mode in which only the left and right rear wheels 5 are driven and a 4WD mode in which both the left and right front wheels 4 and the left and right rear wheels 5 are driven.

[0035] The power transmission mechanism to the left and right rear wheels 5 has a main transmission unit 323 disposed at the rear stage of the engine E via a forward / reverse switching clutch 322, a sub-transmission unit 325 disposed at the subsequent stage thereof, and a rear-wheel differential gear device 326 disposed at the subsequent stage thereof. And at the base of the rear axle 405 connecting the rear-wheel differential gear device 326 and the left and right rear wheels 5, left and right brake devices 312 are provided on the left and right, respectively. The left and right brake devices 312 are operated by a brake pedal 13 (see FIG. 2) provided on the machine body.

[0036] Also, it is input to a transmission shaft 404 via an idle gear provided at the subsequent stage of the sub-transmission unit 325, and power is transmitted to the left and right front wheels 4 via a 4WD clutch 324 and a front-wheel differential gear device 320.

[0037] The steering angle sensor 304 detects the operation amount of the steering wheel 9, that is, the steering angle (steering angle). The steering angle is detected in each of the left and right directions with reference to the case where the operation amount of the steering wheel 9 is zero, that is, when the tractor 1 is traveling straight.

[0038] The left and right brake devices 312 provided on the left and right rear wheels 5 function when the operator depresses the brake pedal 13, causing the brake cylinder 311 to act by hydraulic pressure. That is, the left brake device 312L provided at the base of the left rear axle 405L is connected to the left brake cylinder 311L, and the right brake device 312R provided at the base of the right rear axle 405R is connected to the right brake cylinder 311R.

[0039] The left and right brake cylinders 311L and 311R are connected to both brake solenoids 350 connected to the control unit 100. Therefore, when a predetermined brake signal is input to the control unit 100, the control unit 100 drives both brake solenoids 350 to switch the single brake valve 351 and the both brake valve 352. When individually operating the left and right brake devices 312L and 312R to reduce the turning radius or to cope with the inner and outer wheel difference in 4WD, it is switched to the single brake valve 351, and when simultaneously operating the left and right brake devices 312L and 312R, it is switched to the both brake valve 352.

[0040] Both brake solenoids 350 are connected to the left and right brake solenoids 330L and 330R connected to the control unit 100. Therefore, when a predetermined brake signal is input to the control unit 100, the control unit 100 drives the brake solenoid 330 to switch the left single brake valve 331, the neutral valve 332, and the right single brake valve 333. When only operating the right brake device 312R, the control unit 100 is switched to the right single brake valve 333, when only operating the left brake device 312L, it is switched to the left single brake valve 331, and when not operating both the left and right brake devices 312L and 312R, it is switched to the neutral valve 332. In the case of simultaneously operating both brakes, in this embodiment, it is switched to the right single brake valve 333.

[0041] The left and right brake solenoids 330L and 330R are connected to a hydraulic pump 341 via a proportional valve 342. Therefore, the control unit 100 can adjust the brake pressure of either or both of the brake devices 312L and 312R by adjusting the flow rate of the hydraulic oil supplied from the hydraulic pump 341 by the proportional valve 342. Note that both brake solenoids 350 and the brake solenoid 330 constitute a hydraulic circuit together with, for example, the hydraulic pump 341, the relief valve 340, and the like.

[0042] Next, the control system of the tractor 1 centered on the control device 40 will be described with reference to FIG. 5. FIG. 5 is a block diagram showing an example of the control system of the tractor 1. As shown in FIG. 5, the control device 40 includes an engine control unit 41, a travel control unit 42, a work implement control unit 43, and an image recognition unit 44. The engine control unit 41 controls the rotational speed of the engine E. The travel control unit 42 controls the travel speed of the travel vehicle body 2 (see FIG. 1) by controlling the rotation of the drive wheels. The work implement control unit 43 controls the lifting device 12 to control the lifting of the work implement W.

[0043] The control device 40 can control each part by electronic control, and includes a processing unit having a CPU (Central Processing Unit) and the like, and a storage unit in which various programs and data are stored. In the present embodiment, the travel control unit 42 stores field data including the position and shape of the field on which the travel vehicle body 2 travels.

[0044] As shown in FIG. 5, various sensors such as a positioning device (GNSS) 30, an engine rotation sensor 23, a vehicle speed sensor 24, a lift arm sensor 25, and a pressure sensor 26 are connected to the control device 40. Note that the engine rotation sensor 23 detects the rotational speed of the engine E. The vehicle speed sensor 24 detects the travel speed (vehicle speed) of the travel vehicle body 2 (see FIG. 1). The pressure sensor 26 detects the pressure of the main cylinder 121.

[0045] The control device 40 receives the position information of the traveling vehicle body 2 in a field or the like from the positioning device 30, the rotational speed of the engine E from the engine rotation sensor 23, the traveling speed of the traveling vehicle body 2 from the vehicle speed sensor 24, the height of the working machine W from the lift arm sensor 25, and the pressure of the main cylinder 121 from the pressure sensor 26. Further, a left and right separate braking selection switch 33 and a blinker lever 31 are connected to the control device 40, and operation signals are input thereto respectively.

[0046] Further, an engine control unit 41 is connected to the engine E in the control device 40, a traveling control unit 42 is connected to a steering device 51, a transmission device 52, left and right braking devices 312, etc., a working machine control unit 43 is connected to a lifting device 12, and an image recognition unit 44 is connected to a camera 32.

[0047] Among these, the traveling control unit 42 outputs an operation signal to both brake solenoids 350 and the brake solenoid 330 so that a single brake is applied to the rear wheel 5R (see FIG. 4). The right braking device 312R functions when a right brake cylinder 311R, which is an actuator for operating the right braking device 312R, acts by hydraulic pressure. The traveling control unit 42 outputs an operation signal to both brake solenoids 350 and the brake solenoid 330 so that a single brake is applied to the rear wheel 5L (see FIG. 4). The left braking device 312L functions when a left brake cylinder 311L, which is an actuator for operating the left braking device 312L, acts by hydraulic pressure.

[0048] Further, the working machine control unit 43 outputs a working machine lifting signal to the lifting device 12. The lifting device 12 drives the working machine W to lift or lower based on the working machine lifting signal output from the working machine control unit 43. The working machine control unit 43 recognizes the lifting or lowering position based on the detection result of the lift arm sensor 25 and the working machine W, and functions as a lifting or lowering position recognition unit.

[0049] Further, the image recognition unit 44 receives the image captured by the camera 32. The image recognition unit 44 recognizes the direction of the operator's line of sight from the image captured by the camera 32. Note that a right label R and a left label L are provided on the left and right sides of the meter panel 27, and when the operator looks left and right, the operator can determine the direction of the line of sight (see FIG. 2).

[0050] Next, with reference to FIG. 6, the braking procedure of the tractor 1 according to the first embodiment will be described. FIG. 6 is a flowchart showing the braking procedure executed by the travel control unit 42.

[0051] As shown in FIG. 6, the travel control unit 42 determines whether the depression of the brake pedal 13 is detected by the brake sensor 50 (step S101).

[0052] When the travel control unit 42 determines that the depression of the brake pedal 13 is detected by the brake sensor 50 (step S101: Yes), it determines whether the position of the aircraft recognized by the positioning device 30 is within the field in the field data (step S102).

[0053] When the travel control unit 42 determines that the depression of the brake pedal 13 is not detected by the brake sensor 50 (step S101: No), the process ends.

[0054] When the travel control unit 42 determines that the position of the aircraft recognized by the positioning device 30 is within the field in the field data (step S102: Yes), it determines whether the left and right brakes are selected by the left and right braking selection switch 33 (step S103).

[0055] When the travel control unit 42 determines that the position of the aircraft recognized by the positioning device 30 is outside the field in the field data (step S102: No), it performs both brakes that operate both the left and right brake devices 312 (step S105), and the process ends.

[0056] When the travel control unit 42 determines that the left and right brakes are selected by the left-right separate braking selection switch 33 (step S103: Yes), it performs single braking (step S104) and ends the process. For example, if the right switch of the left-right separate braking selection switch 33 is pressed, the travel control unit 42 performs single braking by operating the right brake device 312R. If the left switch of the left-right separate braking selection switch 33 is pressed, the travel control unit 42 performs single braking by operating the left brake device 312L.

[0057] When the travel control unit 42 determines that the left and right brakes are not selected by the left-right separate braking selection switch 33 (step S103: No), it performs both-brake braking (step S105) and ends the process. For example, if the left-right separate braking selection switch 33 is not pressed, the travel control unit 42 performs both-brake braking.

[0058] In this way, the tractor 1 is not configured such that the operator differentiates the depression of the brake pedal 13. Therefore, the tractor 1 can prevent misdepression of the brake pedal 13 during road travel.

[0059] Alternatively, the left-right separate braking selection unit 20 may be the turn signal lever 31. Hereinafter, the description of the same processing as when the left-right separate braking selection switch 33 is used as the left-right separate braking selection unit 20 will be omitted.

[0060] When the travel control unit 42 determines that the machine body position recognized by the positioning device 30 is a position outside the field in the field data (step S102: No), it performs both-brake braking (step S105) and ends the process. That is, when the traveling vehicle body 2 is traveling on the road, the travel control unit 42 always performs both-brake braking instead of single braking.

[0061] When the travel control unit 42 determines that the left and right brakes are selected by the turn signal lever 31 (step S103: Yes), it performs a single brake and ends the process. For example, if the turn signal lever 31 is operated so that the right turn signal 14 blinks, the travel control unit 42 performs a single brake by operating the right brake device 312R. If the turn signal lever 31 is operated so that the left turn signal 14 blinks, the travel control unit 42 performs a single brake by operating the left brake device 312L.

[0062] When the travel control unit 42 determines that the left and right brakes are not selected by the turn signal lever 31 (step S103: No), it performs both brakes (step S105) and ends the process. For example, if the turn signal lever 31 is not operated, the travel control unit 42 performs both brakes.

[0063] Alternatively, the left and right separate braking selection unit 20 may be a camera 32 and an image recognition unit 44.

[0064] When the travel control unit 42 determines that the left and right brakes are selected based on the direction of the operator's line of sight (step S103: Yes), it performs a single brake and ends the process. For example, if the operator is looking at the right label R (for example, for 2 seconds or more), the travel control unit 42 performs a single brake by operating the right brake device 312R. If the operator is looking at the left label L (for example, for 2 seconds or more), the travel control unit 42 performs a single brake by operating the left brake device 312L.

[0065] When the travel control unit 42 determines that the left and right brakes are not selected based on the direction of the operator's line of sight (step S103: No), it performs both brakes (step S105) and ends the process. For example, if the operator is not looking at the right label R and the left label L (for example, looking straight ahead), the travel control unit 42 performs both brakes.

[0066] Alternatively, the operator may raise the right or left hand to select which of the left and right rear wheels 5 to apply the brake. For example, the camera 32 captures an image including the operator's hand, and the image recognition unit 44 recognizes whether the operator is raising the right hand or the left hand.

[0067] When the travel control unit 42 determines that the left and right brakes have been selected based on the operator's hand movement (step S103: Yes), it performs a single brake operation and ends the process. For example, if the operator is raising the right hand, the travel control unit 42 performs a single brake operation by activating the right brake device 312R. If the operator is raising the left hand, the travel control unit 42 performs a single brake operation by activating the left brake device 312L.

[0068] When the travel control unit 42 determines that the left and right brakes have not been selected based on the operator's hand movement (step S103: No), it performs both brakes (step S105) and ends the process. For example, if the operator is not raising a hand (for example, while gripping the steering wheel 9), the travel control unit 42 performs both brakes.

[0069] Alternatively, the tractor 1 may be configured to select which of the left and right rear wheels 5 to apply the brake based on the operator's voice. For example, the tractor 1 is provided with a microphone in the driver's seat 8, and the control device 40 connected to the microphone recognizes the operator's voice.

[0070] When the travel control unit 42 determines that the left and right brakes have been selected based on the operator's voice (step S103: Yes), it performs a single brake operation and ends the process. For example, if the operator is stepping on the brake pedal 13 while saying "right brake", the travel control unit 42 performs a single brake operation by activating the right brake device 312R. If the operator is stepping on the brake pedal 13 while saying "left brake", the travel control unit 42 performs a single brake operation by activating the left brake device 312L.

[0071] When the travel control unit 42 determines that the left and right brakes are not selected based on the operator's voice (step S103: No), it applies both brakes (step S105) and ends the process. For example, if the operator depresses the brake pedal 13 without uttering "right brake" or "left brake", the travel control unit 42 applies both brakes.

[0072] Note that the left and right separate braking selection unit 20 may be configured without the camera 32 and the image recognition unit 44 when the operator selects the left and right brakes using the left and right separate braking selection switch 33. Also, the left and right separate braking selection unit 20 may be configured without the left and right separate braking selection switch 33 when the operator selects the left and right brakes using image recognition such as the operator's line of sight. Further, by providing a LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) in front of the traveling vehicle body 2, the travel control unit 42 may determine whether the aircraft position is within the field based on the image captured by the LiDAR.

[0073] <Second Embodiment> Next, with reference to FIGS. 7 to 10, the brake processing procedure of the tractor 1 according to the second embodiment will be described. FIG. 7 is a schematic left side view of the tractor 1 with the wheeled work implement W1 attached. FIGS. 8 to 10 are flowcharts showing the brake processing procedure executed by the travel control unit 42. Note that the description will focus on the processing different from the first embodiment, and the description of the same processing as the first embodiment will be omitted. Also, the wheeled work implement W1 is a type of work implement W.

[0074] First, with reference to FIG. 7, the configuration of the tractor 1 according to the second embodiment will be described.

[0075] The tractor 1 has a work implement W and a traveling vehicle body 2 that each conform to the ISOBUS, which is a communication standard. An ECU (Electronic Control Unit) for the work implement provided in the work implement W and a travel control unit 42 provided in the traveling vehicle body 2 are in a state where they can communicate with each other via a network. The travel control unit 42 can recognize the type of the work implement W based on a signal sent from the work implement ECU via a connector and a cable. In the present embodiment, the work implement recognition means 34 is composed of the work implement ECU, the connector, and the cable.

[0076] When the traveling vehicle body 2 is in a state where a wheeled work implement W1 such as a trailer or a trailed compost fertilizer applicator is mounted and performs a turn by operating one brake, the turning radius may be too small. Therefore, the travel control unit 42 restricts the operation of one brake by performing the process described below.

[0077] FIGS. 8 to 10 are flowcharts showing the brake processing procedures executed by the travel control unit 42.

[0078] As shown in FIG. 8, when the travel control unit 42 determines that the left and right brakes are selected by the left-right separate braking selection unit 20 (step S103: Yes), it determines whether the wheeled work implement W1 is recognized by the work implement recognition means 34 (step S106).

[0079] When the travel control unit 42 determines that the wheeled work implement W1 is recognized by the work implement recognition means 34 (step S106: Yes), it applies both brakes and ends the process. That is, when the work implement recognition means 34 recognizes the wheeled work implement W1, the travel control unit 42 restricts the operation of one brake. When the travel control unit 42 determines that the wheeled work implement W1 is not recognized by the work implement recognition means 34 (step S106: No), it performs one brake in the same manner as above and ends the process.

[0080] Even when the wheeled working machine W1 is mounted on the traveling vehicle body 2, as long as the wheeled working machine W1 is in a state where it is raised and not towed, there is no risk of being too sharp in turning. Therefore, the travel control unit 42 performs the following-described process to regulate the operation of the single brake.

[0081] As shown in FIG. 9, when the travel control unit 42 determines that the wheeled working machine W1 is recognized by the working machine recognition means 34 (step S106: Yes), it determines whether or not the lifting position of the working machine W recognized by the working machine control unit 43 is at or below a predetermined position (step S107).

[0082] When the travel control unit 42 determines that the lifting position of the working machine W recognized by the working machine control unit 43 is at or below a predetermined position (step S107: Yes), it applies both brakes and ends the process. Also, when the travel control unit 42 determines that the lifting position of the working machine W recognized by the working machine control unit 43 is higher than the predetermined position (step S107: No), it applies a single brake in the same manner as above and ends the process. That is, even when the wheeled working machine W1 is connected to the traveling vehicle body 2, the travel control unit 42 enables the operation of the single brake when the wheeled working machine W1 is raised above the predetermined position. The predetermined position is, for example, a non-working position where the wheeled working machine W1 is raised and is set in advance in the travel control unit 42.

[0083] Even when the lifting position of the working machine W is higher than the predetermined position, there may be a case where the wheeled working machine W1 is not mounted on the traveling vehicle body 2 and the wheeled working machine W1 is not raised only by the rotation of the lift arm 122. Therefore, the travel control unit 42 performs the following-described process to regulate the operation of the single brake.

[0084] As shown in FIG. 10, when the travel control unit 42 determines that the lifting position of the working machine W recognized by the working machine control unit 43 is higher than the predetermined position (step S107: No), it determines whether or not the pressure of the main cylinder 121 detected by the pressure sensor 26 is at or below a predetermined value (step S108).

[0085] When the travel control unit 42 determines that the pressure of the main cylinder 121 detected by the pressure sensor 26 is equal to or lower than a predetermined value (step S108: Yes), it applies both brakes and ends the process. Also, when the travel control unit 42 determines that the pressure of the main cylinder 121 detected by the pressure sensor 26 is greater than the predetermined value (step S108: No), it applies a single brake in the same manner as above and ends the process. That is, even when the work implement recognition means 34 recognizes the wheeled work implement W1 and the lifting position of the work implement W is higher than a predetermined position, the travel control unit 42 restricts the operation of the single brake when the pressure of the main cylinder 121 is equal to or lower than the predetermined value.

[0086] As another configuration example of the tractor 1, a configuration in which left and right brake pedals are respectively provided and an actuator is used for the connection mechanism of the left and right brake pedals is also conceivable. When the travel control unit 42 determines that the wheeled work implement W1 is recognized by the work implement recognition means 34, it may prevent the connection of the left and right brake pedals from being released under any conditions by operating the actuator provided in the connection mechanism of the left and right brake pedals.

[0087] As described above, the tractor 1 according to the embodiment includes a positioning device 30 that recognizes the position of the machine body, left and right front wheels 4 and left and right rear wheels 5 of the machine body, left and right brake devices 312 that brake the left and right rear wheels 5 respectively, a brake pedal 13 that operates the left and right brake devices 312, a brake sensor 50 that detects the depression of the brake pedal 13, a left and right separate braking selection unit 20 that selects which brake of the left and right rear wheels 5 to apply, and a travel control unit 42 that controls a brake cylinder 311 that operates the left and right brake devices 312 and has field data including the position and shape of the field. When the position of the machine body recognized by the positioning device 30 is within the field in the field data and the depression of the brake pedal 13 is detected by the brake sensor 50, the travel control unit 42 performs a single brake operation to operate either one of the left and right brake devices 312 so as to apply the brake to either one of the left and right rear wheels 5 selected by the left and right separate braking selection unit 20. Thereby, the tractor 1 can simplify the foot area of the driver's seat 8 and prevent operation errors.

[0088] Further, the tractor 1 according to the present embodiment includes a steering wheel 9 that operates the traveling direction of the left and right front wheels 4. The left and right separate braking selection unit 20 is a turn signal lever 31 disposed near the steering wheel 9. When the position of the machine body recognized by the positioning device 30 is within the field in the field data and the depression of the brake pedal 13 is detected by the brake sensor 50, the travel control unit 42 performs a single brake operation to operate either one of the left and right brake devices 312 so as to apply the brake to either one of the left and right rear wheels 5 according to the operation direction of the turn signal lever 31. Thereby, the tractor 1 can simplify the foot area of the driver's seat 8 and prevent operation errors and the like. Further, by using the turn signal lever 31 as the left and right separate braking selection unit 20, the tractor 1 does not need to newly provide an operating tool.

[0089] In addition, for the tractor 1 according to the present embodiment, the left and right braking selection unit 20 includes a camera 32 that captures an image including the operator's eyes, and an image recognition unit 44 that recognizes the direction of the operator's line of sight from the image, and selects which of the left and right rear wheels 5 to apply the brake based on the direction of the operator's line of sight. As a result, the tractor 1 simplifies the foot area of the driver's seat 8 and can prevent operation errors and the like. Further, the tractor 1 can easily select the left and right brakes even when the operator is operating the steering wheel 9.

[0090] In addition, the tractor 1 according to the present embodiment includes a work implement recognition means 34 that recognizes the type of the work implement W that can be attached to the rear part of the vehicle body. When the work implement recognition means 34 recognizes the wheeled work implement W1, the travel control unit 42 restricts the operation of the single brake. Thereby, the tractor 1 can prevent operation errors and can turn safely.

[0091] In addition, the tractor 1 according to the present embodiment includes a lifting device 12 that raises and lowers the work implement W, and a work implement control unit 43 that recognizes the lifting position of the work implement W. When the work implement recognition means 34 recognizes the wheeled work implement W1 and the lifting position of the work implement W is below a predetermined position, the travel control unit 42 restricts the operation of the single brake. Thereby, the tractor 1 can prevent operation errors and can turn safely. Further, when the tractor 1 is equipped with the work implement W that has been raised above the predetermined position, there is no problem even if it turns with a single brake, so it can turn in a small radius.

[0092] In addition, the tractor 1 according to the present embodiment has a lifting device 12 including a main cylinder 121 for lifting the lifting device 12 and a pressure sensor 26 for detecting the pressure of the main cylinder 121. When the work implement recognition means 34 recognizes the wheeled work implement W1 and the pressure of the main cylinder 121 is equal to or lower than a predetermined value even if the lifting position of the work implement W is higher than a predetermined position, the travel control unit 42 restricts the operation of the single brake. Thereby, the tractor 1 can prevent operation errors and turn safely. Further, the tractor 1 can restrict the operation of the single brake when the work implement W is not connected to the lifting device 12 by monitoring the pressure of the main cylinder 121.

[0093] Further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspects of the present invention are not limited to the specific details and representative embodiments presented and described above. Accordingly, various changes are possible without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Signs

[0094] 1 Tractor 2 Traveling vehicle body 4 Left and right front wheels 5 Left and right rear wheels 9 Steering handle 12 Lifting device 13 Brake pedal 14 Blinker 20 Left and right separate brake selection unit 26 Pressure sensor 30 Positioning device 31 Blinker lever 32 Camera 34 Work implement recognition means 42 Travel control unit 43 Work implement control unit (lifting position recognition unit) 44 Image recognition unit 50 Brake sensor 121 Main cylinder 311 Brake cylinder (actuator) 312 Left and right braking devices W Working machine W1 Working machine with wheels

Claims

1. A positioning device that recognizes the position of the machine body, The left and right front wheels and the left and right rear wheels of the machine body, Left and right brake devices that brake the left and right rear wheels respectively, A brake pedal that operates the left and right brake devices, A brake sensor that detects the depression of the brake pedal, A left / right differential braking selection unit that selects which of the left and right rear wheels to apply the brake to, A travel control unit that controls an actuator that operates the left and right brake devices and has field data including the position and shape of the field, When the position of the machine body recognized by the positioning device is within the field position in the field data and the depression of the brake pedal is detected by the brake sensor, the travel control unit performs a single brake operation to operate either one of the left and right brake devices so as to apply the brake to either the left or right rear wheel selected by the left / right differential braking selection unit.

2. It is provided with a steering wheel that operates the traveling direction of the left and right front wheels, The left / right differential braking selection unit is a turn signal lever disposed near the steering wheel, When the position of the machine body recognized by the positioning device is within the field position in the field data and the depression of the brake pedal is detected by the brake sensor, the travel control unit performs a single brake operation to operate either one of the left and right brake devices so as to apply the brake to either the left or right rear wheel according to the operation direction of the turn signal lever. The work vehicle according to claim 1.

3. The left / right differential braking selection unit, A camera that captures an image including the eyes of the operator, An image recognition unit that recognizes the direction of the operator's line of sight from the image, The work vehicle according to claim 1, which selects which of the left and right rear wheels to apply the brake based on the direction of the operator's line of sight.

4. Comprising a work implement recognition means for recognizing the type of work implement that can be attached to the rear part of the machine body, The travel control unit restricts the operation of the single brake when the work implement recognition means recognizes a work implement with wheels, according to any one of claims 1 to 3.

5. A lifting device for lifting and lowering the work implement, And a lifting position recognition unit for recognizing the lifting position of the work implement, The travel control unit restricts the operation of the single brake when the work implement recognition means recognizes the work implement with wheels and the lifting position of the work implement is at or below a predetermined position, according to claim 4.

6. The lifting device is A main cylinder for lifting and lowering the lifting device, And a pressure sensor for detecting the pressure of the main cylinder, The travel control unit restricts the operation of the single brake when the work implement recognition means recognizes the work implement with wheels and even when the lifting position of the work implement is higher than the predetermined position, if the pressure of the main cylinder is at or below a predetermined value, according to claim 5.

Images