Work vehicles

Abstract

To provide a work vehicle that improves safety of an operator.SOLUTION: A work vehicle includes: an engine provided in a travelling vehicle body; a hydraulic stepless speed variator for changing the speed of power input from the engine and outputting the power; an operation tool capable of adjusting the vehicle speed of the travelling vehicle body by adjusting a trunnion aperture of the hydraulic stepless speed variator; a setting tool for receiving an operation for changing an upper limit aperture of the trunnion aperture of the hydraulic stepless speed variator by the operation tool, and a control device for setting the upper limit aperture of the trunnion aperture according to the operation state of the setting tool.SELECTED DRAWING: Figure 7

Description

[Technical Field]

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

[0002] BACKGROUND ART Conventionally, there is known a work vehicle in which the vehicle speed of the traveling vehicle body is set in accordance with the depression amount of a speed change pedal provided on the traveling vehicle body, and the traveling vehicle body is caused to travel (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-236714 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, when moving on a slope, such as when loading or unloading a work vehicle onto or from a truck, or when moving a work vehicle in or out of a field, fine adjustment of operating tools such as a gear change pedal is required.

[0005] However, with the above technology, it can be difficult to fine-tune operating tools such as a gear change pedal when moving on an inclined surface due to tilting or vibration of the traveling vehicle body, which can cause the traveling vehicle body to move in an unexpected way when moving on an inclined surface, leaving room for improvement in terms of worker safety.

[0006] The present invention has been made in view of the above, and has an object to provide a work vehicle that improves the safety of workers. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, a work vehicle (1) according to one aspect of the embodiment includes an engine (30) provided in a traveling body (2), a hydraulic continuously variable transmission (14) that changes the speed of power input from the engine (30) and outputs the power, an operating device (36) that can adjust the speed of the traveling body (2) by adjusting the trunnion opening of the hydraulic continuously variable transmission (14), and a setting device (49) that accepts an operation to change the upper limit opening of the trunnion opening of the hydraulic continuously variable transmission (14) using the operating device (36); an inclination sensor (92) for detecting an inclination angle in the longitudinal direction of the traveling vehicle body (2); A control device (100) is provided which sets the upper limit of the trunnion opening depending on the operating state of the setting tool (49). The control device (100) sets the vehicle speed mode to a first vehicle speed mode in which the upper limit opening degree is a first upper limit opening degree, or a second vehicle speed mode in which the upper limit opening degree is a second upper limit opening degree, in response to the operation of the setting tool (49). The second vehicle speed mode is a mode in which the speed of the traveling vehicle body (2) is slower than in the first vehicle speed mode. When the tilt angle is equal to or greater than a predetermined angle, the control device (100) sets the vehicle speed mode to the second vehicle speed mode. The predetermined angle is changeable. do. [Effects of the Invention]

[0008] According to one aspect of the embodiment, the work vehicle can improve the safety of the worker. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view showing a work vehicle. [Figure 2] FIG. 2 is a plan view showing the work vehicle. [Figure 3] FIG. 3 is an explanatory diagram of the HST. [Figure 4] FIG. 4 is a diagram illustrating the lever guide portion. [Figure 5] FIG. 5 is a diagram illustrating the setting switches. [Figure 6] FIG. 6 is a block diagram showing a control system centered on the control device of the seedling transplanter. [Figure 7] FIG. 7 is a diagram showing the relationship between the position of the main speed change operation lever, the trunnion opening, and the engine speed. [Figure 8] FIG. 8 is a flowchart showing the process of setting an upper limit of the trunnion opening according to the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a method for setting a work area. DETAILED DESCRIPTION OF THE INVENTION

[0010] First, an overview of a work vehicle 1 according to an embodiment will be described with reference to Figures 1 and 2. Figure 1 is a side view showing the work vehicle 1. Figure 2 is a plan view showing the work vehicle 1.

[0011] In the following description, the forward / rearward direction refers to the direction of travel of the work vehicle 1 when traveling straight, with the front side of the traveling direction being defined as "front" and the rear side being defined as "rear." The traveling direction of the work vehicle 1 is the direction from the driver's seat 41 toward the handlebars 35 (steering device) when traveling straight (see Figures 1 and 2).

[0012] The left-right direction is a direction that is horizontally perpendicular to the front-rear direction and defines left and right facing the "front." In other words, when the operator (also referred to as an operator) is seated in the operator's seat 41 and facing forward, the left-hand side is the "left" and the right-hand side is the "right."

[0013] The up-down direction is the vertical direction. The front-rear direction, left-right direction, and up-down direction are perpendicular to each other. Each direction is defined for the convenience of explanation, and the present invention is not limited to these directions.

[0014] In this embodiment, the work vehicle 1 will be described as a riding seedling transplanter 1 that is equipped with a seedling planting unit 4 as a work device and that receives seedlings in a field. As shown in Figures 1 and 2, the seedling transplanter 1 is equipped with the seedling planting unit 4, which can be raised and lowered via a lifting link mechanism 3 on the rear side of the traveling body 2, to plant seedlings in the field.

[0015] The main body of the fertilizer applicator 5 is disposed on the upper rear side of the traveling body 2. If the work vehicle 1 is not a seedling transplanter 1, it may be provided with a sowing device that supplies seeds as a work device.

[0016] The traveling body 2 is a four-wheel drive vehicle equipped with left and right front wheels 10 and rear wheels 11, which are also driving wheels. On the front side of the main frame 15 that forms the body skeleton of the traveling body 2, there are provided a transmission case 13 that transmits driving force to the seedling planting section 4 and the like, and a hydraulic continuously variable transmission 14 that outputs driving force supplied from the engine 30, i.e., the rotation generated by the engine 30, to the transmission case 13.

[0017] The continuously variable transmission 14 is a hydrostatic continuously variable transmission known as an HST (Hydro Static Transmission). In the following, a case where the continuously variable transmission is the HST 14 will be described.

[0018] The HST 14 will now be described with reference to Fig. 3. Fig. 3 is an explanatory diagram of the HST 14.

[0019] 3, the HST 14 uses power from the engine 30 to drive a hydraulic pump 141 to generate hydraulic pressure, which is then converted into mechanical power (rotational power) by a hydraulic motor 142 and output. At this time, by operating the main transmission operation lever 36 (described later) via a trunnion shaft actuator such as an HST motor 146, the rotation angle of a trunnion shaft 147 of the HST 14 (hereinafter referred to as the "trunnion opening") is changed, and the tilt angle of a swash plate 148 is thereby changed, thereby allowing the output of the HST 14 to be changed continuously.

[0020] That is, pressure oil according to the tilt angle of the swash plate 148 is supplied from a hydraulic closed circuit 143 to a hydraulic motor 142, and this hydraulic motor 142 drives an output shaft 145, thereby changing the rotational speeds of the front wheels 10 and rear wheels 11. In this way, the HST 14 converts the power generated by the engine 30 into power for propelling the traveling body 2, and by changing the output and output direction, it is possible to control the forward / reverse movement and traveling speed (vehicle speed) of the traveling body 2. In FIG. 3, reference numeral 80 denotes the input shaft of the HST 14, which is connected to the output shaft 30a of the engine 30 via a main clutch 30b. The trunnion shaft actuator may be of a hydraulic type.

[0021] 1 and 2, an auxiliary transmission mechanism 16 is provided within the transmission case 13 to switch the driving mode of the traveling vehicle body 2 between high-speed mode for road driving and low-speed mode for planting seedlings. That is, the auxiliary transmission mechanism 16 switches between high-speed mode (road speed) and low-speed mode (planting speed). Front wheel final cases 10a are provided on the left and right sides of the transmission case 13, and front wheels 10 are attached to left and right front axles 10b that protrude outward from front wheel support parts that can change the steering direction of the left and right front wheel final cases 10a.

[0022] In addition, rear wheel gear cases 11a are attached to both the left and right sides of a rear frame 22 (see Figure 2) that is arranged laterally on the rear side of the main frame 15, and rear wheels 11 are attached to left and right rear axles 11b that protrude outward from the rear wheel gear cases 11a, respectively.

[0023] Left and right link support frames 23 that support the lifting link mechanism 3 protrude upward from the upper part of the rear frame 22. A pair of left and right lower link arms 24 are provided below and between the left and right link support frames 23. A hydraulically operated lifting cylinder 25 is provided between the left and right lower link arms 24.

[0024] An upper link arm 26 is provided above the lifting cylinder 25, forming a parallel link mechanism, the lifting link mechanism 3. The left and right lower link arms 24, the lifting cylinder 25, and the other end of the upper link arm 26, each of which has one end connected to the traveling vehicle body 2, are attached to the front of the seedling planting section 4.

[0025] An engine 30 is mounted on the main frame 15. Rotational power of the engine 30 is transmitted to the transmission case 13 via the belt transmission device 21 and the HST 14. The rotational power transmitted to the transmission case 13 is changed in speed by the sub-transmission mechanism 16 inside the transmission case 13, and then separated into traveling power and externally extracted power.

[0026] The rotational power of the engine 30 is transmitted to a hydraulic pump. The hydraulic pressure generated by the hydraulic pump is supplied to the HST 14, a power steering mechanism 88 (see FIG. 3) of the handle 35, the lift cylinder 25, etc.

[0027] The externally extracted power extracted from the rotational power transmitted to the transmission case 13 is transmitted to the planting clutch case 27 provided at the rear of the running body 2, and is transmitted from the planting clutch case 27 to the seedling planting section 4 via the planting transmission shaft 67.

[0028] Meanwhile, left and right drive shafts 42 are provided at the rear of the transmission case 13. Rotational power from the engine 30 is transmitted via the transmission case 13 and the drive shafts 42 to the left and right rear wheel gear cases 11a.

[0029] A side clutch 44 (see FIG. 4) that turns on and off the power transmission to the left and right drive shafts 42 is disposed upstream of the left and right drive shafts 42 in the power transmission direction. As shown in FIG. 1, a side clutch pedal 43a that turns on and off the left and right side clutches 44 is provided at the front lower part of the cockpit 41 and on one of the left and right sides.

[0030] Of the left and right side clutch pedals 43a, when the side clutch pedal 43a on the inside of the turn is depressed to disengage the side clutch 44, and then the steering wheel 35 is operated to make a turn, the drive rotation of the rear wheel 11 on the inside of the turn can be completely cut off.

[0031] A bonnet 39 with an operation panel 38 arranged on top for operating each section is provided on the upper front side of the traveling vehicle body 2. The operation panel 38 is provided with a monitor 86 (see FIG. 4) and the like.

[0032] The hood 39 is also provided with a handle 35 for steering the traveling vehicle body 2, a main speed change operation lever 36 for operating the HST 14 and the seedling planting section 4, and an auxiliary speed change operation lever 37 for operating the auxiliary speed change mechanism 16.

[0033] The main speed change operation lever 36 is an operation tool (first operation tool) that can adjust the vehicle speed of the traveling vehicle body 2 by adjusting the opening degree of the trunnion shaft 147 of the HST 14. The main speed change operation lever 36 is operated, for example, by the driver. The main speed change operation lever 36 accepts speed change operations by the driver.

[0034] The main transmission operation lever 36 is provided so as to be movable along a lever guide 815, for example, as shown in Fig. 4. Fig. 4 is a diagram illustrating the lever guide 815. As shown in Fig. 4, the lever guide 815 is largely divided into a forward travel area 811 on the front side of the vehicle body, a reverse travel area 813 on the rear side of the vehicle body, and a neutral area 812 sandwiched between them. Note that the lever guide 815 in Fig. 4 is merely an example and is not limited to this.

[0035] When the main speed change lever 36 is positioned in the forward travel area 811, the seedling transplanter 1 moves forward, and the closer it is to the front, the faster it moves. When the main speed change lever 36 is positioned in the reverse travel area 813, the seedling transplanter 1 moves backward, and the closer it is to the rear, the faster it moves.

[0036] That is, main transmission control lever 36 is provided so that its position can be changed across a forward travel region 811 and a reverse travel region 813, sandwiching a neutral region 812, and the output of HST 14 can be adjusted depending on the operation position. That is, the tilt angle of swash plate 148 of HST 14 changes depending on the amount of operation of main transmission control lever 36 within lever guide portion 815, and the output from HST 14, i.e., the travel speed, is changed continuously.

[0037] The rotation speed of the engine 30 is set by the amount of operation of the main transmission operation lever 36. For example, when the main transmission operation lever 36 is positioned in the forward travel region 811, the rotation speed of the engine 30 increases as the main transmission operation lever 36 approaches the frontmost position.

[0038] On the other hand, when the main speed change operation lever 36 is positioned in the neutral region 812, the output from the HST 14 is stopped and the seedling transplanter 1 stops. Furthermore, at this time, the seedling transplanter 1 is designed so that the brakes are forcibly applied to the front wheels 10 and rear wheels 11.

[0039] When the driver stops operating the main speed change operation lever 36, the main speed change operation lever 36 is held in the position where the driver stopped operating it.

[0040] As shown in Fig. 5, the hood 39 is provided with a setting switch 49 (setting tool) that can change and set the upper limit of the trunnion opening of the HST 14. Fig. 5 is a diagram illustrating the setting switch 49. The setting switch 49 is, for example, a switch that is provided so as to be rotatable in the vertical direction. The setting switch 49 can be rotated by the operator. The setting switch 49 accepts the operator's operation to set the upper limit of the opening. The setting switch 49 is a switch for setting the upper limit of the trunnion opening when the traveling vehicle body 2 is moving forward and when it is moving backward. The setting switch 49 may be a button type or the like.

[0041] When the setting switch 49 is in the upper first position, for example, the vehicle speed mode is set to the first vehicle speed mode. In the first vehicle speed mode, the upper limit of the trunnion opening is set to the first upper limit. The first upper limit is the normal upper limit and is set according to the position of the main transmission operation lever 36.

[0042] When the setting switch 49 is, for example, in the lower second position, the vehicle speed mode is set to the second vehicle speed mode. In the second vehicle speed mode, the upper limit of the trunnion opening is set to the second upper limit. The second upper limit is smaller than the first upper limit. In other words, the second vehicle speed mode is a mode in which the speed of the traveling vehicle body 2 is slower than in the first vehicle speed mode.

[0043] The first upper limit opening degree and the second upper limit opening degree are set to different opening degrees when the traveling vehicle body 2 is moving forward and when it is moving backward. For example, in the second vehicle speed mode, the second upper limit opening degree when moving backward is smaller than the second upper limit opening degree when moving forward.

[0044] For example, the vehicle speed in the second vehicle speed mode is about 20% of the vehicle speed in the first vehicle speed mode. Also, for example, the vehicle speed in the second vehicle speed mode when traveling backward is about 30% of the vehicle speed in the first vehicle speed mode when traveling backward.

[0045] The trunnion opening here is the opening relative to the state in which the swash plate 148 (see FIG. 3) is not tilted. The trunnion openings for forward and reverse travel are, for example, amounts of change relative to the state in which the swash plate 148 is not tilted, and both will be described as positive values. Separate setting switches 49 may be provided for forward travel and reverse travel.

[0046] 1 and 2, an openable front cover 40 is provided in front of the hood 39. Inside the front cover 40, a fuel tank, a battery, and an interlocking mechanism that rotates the left and right front wheels 10 and the lower sides of the left and right front wheel final cases 10a in response to steering of the handlebars 35 are provided. The front wheels 10 are, for example, steerable wheels that turn in response to steering of the handlebars 35.

[0047] An engine cover 30c that covers the top and sides of the engine 30 is provided behind the hood 39 and above the engine 30, and a pilot's seat 41 where the pilot sits is provided above the engine cover 30c.

[0048] The fertilizer applicator 5 is provided behind the driver's seat 41, at the rear end of the main frame 15. The driving force of the fertilizer applicator 5 is transmitted by a fertilizer transmission mechanism provided so as to face the fertilizer applicator 5 from one of the left and right rear wheel gear cases 11a.

[0049] Approximately horizontal floor steps 33 are formed on both the left and right sides of the lower part of the engine cover 30c and the hood 39. As shown in Fig. 2, the floor steps 33 are partially lattice-shaped, so that even if mud gets on the shoes of an operator walking on the floor steps 33, the mud will fall into the field.

[0050] An accelerator pedal 110 (second operating tool) that can be depressed by the driver is provided on the floor step 33. The accelerator pedal 110 is biased toward a predetermined initial position by a biasing means such as a spring. Specifically, when the driver is not depressing the accelerator pedal 110, the accelerator pedal 110 is biased by the biasing means to return to the initial position. When the driver depresses the accelerator pedal 110, the accelerator pedal 110 rotates from the initial position in accordance with the driver's depressing force. When the driver stops depressing the accelerator pedal 110, the accelerator pedal 110 returns to the initial position by the biasing force of the biasing means.

[0051] 2, a rear step 330 is connected to the rear of the floor step 33. The surface of the rear step 330 is preferably provided with an anti-slip finish, for example, with a pattern of multiple protrusions, to prevent feet from slipping during work.

[0052] In addition, on the front side of the traveling body 2 and on both the left and right sides, spare seedling frames 50 are provided, each with a seedling frame support 51 on which multiple spare seedling loading tables 52 are arranged at intervals in the vertical direction, so that work materials such as seedlings and fertilizer bags to be replenished in the seedling planting section 4 can be placed.

[0053] A seedling tank 53 for carrying seedlings to be planted in the field is attached to the rear end of the lifting link mechanism 3, along with a sliding mechanism for sliding it left and right. Seedling partition fences 54, which are long in the vertical direction, are placed on the seedling tank 53 at predetermined intervals in the horizontal direction. Below the seedling tank 53 is a seedling planting device 55 that picks up the loaded seedlings and plants them in the field.

[0054] The seedling planting device 55 plants eight rows at the same time, the same number as the number of rows to be planted separated by the seedling partition fence 54. Four planting transmission cases 56 are arranged at intervals below the seedling tank 53, and planting rotaries 57 are attached to both the left and right sides of the planting transmission cases 56, which rotate to pick up seedlings using planting rods 58 and plant them in the field.

[0055] In the fertilizer applicator 5, the fertilizer hopper 70 that stores the fertilizer is divided into the same number of sections as the number of working rows in the seedling planting section 4 (eight rows in the example shown in FIG. 2). Note that the eight-row fertilizer hopper 70 is long in the left-right direction, which reduces the convenience of adding fertilizer and attaching and detaching it, so it may have a so-called side fertilizer application structure, in which sections divided into four rows are lined up on each side.

[0056] Below the fertilizer hopper 70, a dispensing device 71 that supplies a set amount of fertilizer is provided for each row. Below the dispensing device 71, a ventilation duct 72 is provided in the left-right direction, through which conveying air passes to move the fertilizer. Below the dispensing device 71, a fertilizer hose 73 is provided to guide the fertilizer near the seedling planting position in the seedling planting section 4. Also, at one end of the ventilation duct 72, a blower 74 that is operated by an electric blower motor 76 to generate conveying air is provided.

[0057] The amount of fertilizer supplied to the field (fertilizer application amount) can be adjusted by controlling the dispensing device 71. For example, the amount of fertilizer supplied to the field can be adjusted by controlling the rotation speed of a dispensing section that is provided in the dispensing device 71 and has a recess into which the fertilizer flows from the fertilizer application hopper 70.

[0058] 1 and 2, a center float 62C that slides on the field surface and two side floats 62L and 62R are provided rotatably about axes below the seedling planting section 4. The center float 62C and the left and right side floats 62L and 62R are sometimes collectively referred to as floats 62.

[0059] In addition, below the seedling planting section 4, and forward of the float 62, a ground leveling rotor 63 for leveling unevenness in the field surface is provided. Driving force is transmitted to the ground leveling rotor 63 from the rear wheel gear case 11a on the other left or right side via a rotor transmission shaft 63a.

[0060] 1, line-drawing markers 65 are provided on both the left and right sides of the seedling planting section 4. One of the markers 65 touches the ground on the field surface to form a groove that serves as a guide for traveling in the next work row (next process). When one of the markers 65 touches the ground, the other moves upward, and when the seedling planting section 4 is raised during rotation, both the left and right sides move upward, and when the seedling planting section 4 is lowered after rotation, one of the markers 65 moves upward and the other moves downward.

[0061] 1 and 2, a center mascot 66 that is long in the vertical direction is provided in the center of the left and right of the traveling vehicle body 2, in front of the hood 39. By aligning the center mascot 66 with the grooves formed in the field by the left and right line markers 65, it becomes possible to travel in accordance with the working position of the previous working row, improving working accuracy and preventing non-working.

[0062] Depending on the soil quality of the field, the guide lines formed by the left and right line-drawing markers 65 may quickly become buried, causing the guide for going straight to disappear. In such cases, it is advisable to use the left and right side markers 19, which are located forward of the left and right line-drawing markers 65. In other words, by moving the left and right side markers 19 outward and positioning the side markers 19 above the planted seedlings, planting work can be performed in accordance with the planting of the seedlings in the previous work row.

[0063] As shown in FIG. 1, the seedling transplanter 1 is also equipped with a position detection device 150. The position detection device 150 detects the current position and orientation of the seedling transplanter 1. That is, the position detection device 150 detects information about the position of the traveling body 2 and the orientation of the traveling body 2. The position detection device 150 includes, for example, an orientation sensor and positioning means such as a GPS (Global Positioning System) or a GNSS (Global Navigation Satellite System). The position detection device 150 may be composed of multiple devices. The position detection device 150 may include a camera or an ultrasonic sensor, and may acquire a turning position in the field and detect the distance to the turning position.

[0064] For example, the position detection device 150 receives positioning information from the positioning means, creates current position information and direction information of the traveling vehicle body 2 based on the received positioning information, and detects the current position and direction. The position detection device 150 is attached to the mounting stay 59, for example, and disposed above the traveling vehicle body 2.

[0065] A straight-line control program and a turning control program, which are created based on position information from the position detection device 150, are stored in different locations. The straight-line control program is stored, for example, in a straight-line control ECU (Electronic Control Unit) 100a in the position detection device 150, and the turning control program is stored, for example, in a turning control ECU 100b housed in the hood 39. The straight-line control ECU 100a and the turning control ECU 100b are included in a control device 100 (see FIG. 3), which will be described later. The straight-line control ECU 100a and the turning control ECU 100b may be stored in the same ECU.

[0066] Next, the control system of the seedling transplanter 1 will be described with reference to Fig. 6. Fig. 6 is a block diagram showing the control system centered on the control device 100 of the seedling transplanter 1. The seedling transplanter 1 is capable of controlling each part by electronic control, and is equipped with a control device (hereinafter referred to as a controller) 100 that controls each part.

[0067] The controller 100 is provided with a processing section having a CPU (Central Processing Unit) and the like, a memory section such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an input / output section, which are interconnected to allow signals to be exchanged between them. The memory section stores computer programs and the like for controlling the seedling transplanter 1. The controller 100 performs each function by reading out the computer programs and the like stored in the memory section.

[0068] The controller 100 is connected to actuators such as a throttle motor 80, hydraulic control valves 81 and 82, a planting clutch actuation solenoid 83, a side clutch actuation solenoid 84, an HST motor 146, a line drawing marker lifting motor 87, a steering motor 95, and a differential lock switching motor 96.

[0069] The throttle motor 80 increases or decreases the rotation speed of the output shaft 30a of the engine 30 by operating a throttle that adjusts the amount of air intake into the engine 30. The hydraulic control valve 81 controls the extension and retraction of the lifting cylinder 25. The hydraulic control valve 82 controls the power steering mechanism 88. The power steering mechanism 88 changes the direction of the front wheels 10, which are the steering wheels of the traveling body 2. The planting clutch actuation solenoid 83 actuates the planting clutch 27a. When the planting clutch 27a is in the "on" state, the planting rotary 57 rotates and seedlings are planted by the planting rod 58. When the planting clutch 27a is in the "off" state, the planting rotary 57 does not rotate and seedlings are not planted by the planting rod 58.

[0070] The side clutch actuation solenoid 84 actuates the side clutch 44, which switches the state of power transmission to the rear wheels 11 (see FIG. 1). The side clutch 44 is provided on each of the left and right rear wheels 11, and two side clutch actuation solenoids 84 are provided corresponding to each side clutch 44.

[0071] The HST motor 146 changes the inclination angle of the swash plate 148 of the HST 14 by changing the trunnion opening of the HST 14. The steering motor 95 is a motor that drives the handle 35, which is a steering device that adjusts the steering amount (steering angle) of the front wheels 10 (see FIG. 1) when automatic turning control is performed. The steering motor 95 rotates the handle 35. The line drawing marker lifting motor 87 lifts and lowers the line drawing marker 65.

[0072] The differential lock switching motor 96 is a motor that switches between operating and deactivating a differential lock mechanism 97 (hereinafter referred to as the differential lock mechanism) that rotates the left and right running wheels, specifically the left and right front wheels 10, at the same rotational speed. When the differential lock mechanism 97 is engaged, the left and right running wheels rotate at the same rotational speed.

[0073] The controller 100 is connected to detection devices such as a rotation speed sensor 90, a steering amount sensor 91, and an inclination sensor 92. Two rotation speed sensors 90 are provided corresponding to the left and right rear wheels 11, and detect the rotation speeds of the left and right rear wheels 11, respectively. Note that the rotation speed sensors 90 may also detect the rotation speeds of the left and right front wheels 10.

[0074] The steering amount sensor 91 detects the operating position of the steering wheel 35, which is a steering device, i.e., the steering amount (steering angle) of the front wheels 10. The steering amount sensor 91 is provided, for example, on a shaft connected to a pitman arm. The steering amount is detected in both the left and right directions, with the value when the steering wheel 35 is in a preset straight-ahead position being used as a reference value.

[0075] The inclination sensor 92 detects the inclination angle of the traveling vehicle body 2. The inclination sensor 92 detects the inclination angle in the front-rear direction of the traveling vehicle body 2. The inclination sensor 92 is, for example, a G sensor.

[0076] In addition, signals are input to the controller 100 as operation signals from the main speed change operation lever 36, the sub-speed change operation lever 37, the setting switch 49, the autonomous driving switch 46, the planting section lifting / lowering switch 47, the automatic straight-line switching switch 45, the automatic turning switching switch 48, and the accelerator pedal 110.

[0077] The autonomous driving changeover switch 46 is a switch that switches whether or not autonomous driving is performed. Specifically, the autonomous driving changeover switch 46 is a switch that switches the driving mode between manual driving mode and autonomous driving mode (automatic driving mode). The manual driving mode is a mode in which the vehicle drives by manual operation by the operator. The autonomous driving mode is a mode in which the vehicle drives automatically without manual operation by the operator.

[0078] For example, when the autonomous driving selector switch 46 is "ON," the driving mode is set to the autonomous driving mode. When the autonomous driving selector switch 46 is "OFF," the driving mode is set to the manual driving mode. When the autonomous driving selector switch 46 is turned "ON," the automatic straight driving selector switch 45 and the automatic turning selector switch 48 are turned "ON." In other words, once the driving mode is set to the autonomous driving mode, the automatic straight driving selector switch 45 and the automatic turning selector switch 48 can be changed to "OFF" by the operator, even if they have been turned "ON."

[0079] The planting section lifting / lowering switch 47 is a switch that switches whether to lift or lower the seedling planting section 4. The planting section lifting / lowering switch 47 can be changed to the "up" and "down" positions.

[0080] When the planting section lift switch 47 is in the "up" position, the seedling planting section 4 rises to a predetermined raised position and the seedling planting device 55 stops, entering a non-ground operation state. When the seedling planting section 4 enters the non-ground operation state, the planting clutch 27a enters the "off" state.

[0081] When the planting unit lift switch 47 is in the "down" position, the seedling planting unit 4 descends to a predetermined lowered position and the seedling planting device 55 enters an operating state. In other words, the planting unit lift switch 47 is a switch that detects the operating state of the seedling planting unit 4. Note that a separate switch may be provided to detect the operating state of the seedling planting unit 4. When the seedling planting unit 4 enters an operating state, the planting clutch 27a enters the "on" state.

[0082] The automatic straight-line driving selector switch 45 is a switch that switches whether or not automatic straight-line driving is enabled. When the automatic straight-line driving selector switch 45 is set to "ON," a driving assist function, which will be described later, is enabled, and automatic straight-line driving can be performed. When the automatic straight-line driving selector switch 45 is set to "OFF," the driving assist function is disabled, and automatic straight-line driving cannot be performed.

[0083] The automatic turning selector switch 48 is a switch that switches whether or not automatic turning is enabled. When the automatic turning selector switch 48 is set to "ON," the turning assist function, which will be described later, is enabled, and automatic turning can be performed. When the automatic turning selector switch 48 is set to "OFF," the turning assist function is disabled, and automatic turning cannot be performed. When the automatic turning selector switch 48 is set to "OFF," automatic turning is not performed even if the conditions for performing automatic turning are met.

[0084] The controller 100 switches the driving mode between a manual driving mode and an autonomous driving mode in response to the operation of the autonomous driving changeover switch 46, the automatic straight driving changeover switch 45, and the automatic turning changeover switch 48.

[0085] Furthermore, the controller 100 receives input of information such as the current position of the traveling vehicle body 2 from the position detection device 150. The controller 100 executes an autonomous traveling mode in which the traveling vehicle body 2 performs work while traveling automatically.

[0086] The controller 100 has an autonomous driving mode (automatic driving mode) in which the controller 100 controls the steering motor 95 while feeding back the steering amount of the front wheels 10 (see FIG. 1) to operate the steering wheel 35. The autonomous driving mode includes an automatic straight-ahead mode and an automatic turning mode.

[0087] In the automatic straight-line mode, the steering motor 95 is controlled so that the traveling vehicle body 2 moves straight along a preset straight-line path. In the automatic straight-line mode, the traveling vehicle body 2 moves straight without the driver's operation while the seedling planting unit 4 plants seedlings in the field. In other words, the traveling assist function for transplanting seedlings into the field is enabled and executed while the traveling vehicle body 2 moves automatically straight.

[0088] In the automatic turning mode, when the traveling vehicle body 2 reaches a predetermined planting end position, the seedling planting unit 4 stops planting seedlings, and the steering motor 95 is controlled to turn the traveling vehicle body 2 along a predetermined turning path. The predetermined planting end position is set, for example, based on the travel distance of the process where the work was performed and position information related to the process where the work was performed.

[0089] In the automatic turning mode, for example, the seedling planting unit 4 is raised and put into a non-working state, and the traveling body 2 turns automatically without the operator's operation. In other words, the turning assist function that turns the traveling body 2 without the seedling planting unit 4 planting seedlings is enabled, and the turning assist function is executed.

[0090] Moreover, various types of information are input to the controller 100 from a remote control device 170 (hereinafter referred to as "remote control"). For example, various types of information are input to the controller 100 from the remote control 170 via a receiver 180 (see FIG. 1). The receiver 180 is attached to, for example, a mounting stay 59 (see FIG. 1) and is arranged above the front side of the traveling vehicle body 2. Note that multiple receivers 180 may be provided. The mounting stay 59 is attached to the traveling vehicle body 2.

[0091] The remote control 170 can remotely control the seedling transplanter 1. The remote control 170 is a terminal device such as a smartphone. The remote control 170 transmits control signals in response to operations by an operator. The remote control 170 is communicably connected to the controller 100 via short-range wireless communication such as Wi-fi (registered trademark) or BLE (Bluetooth (registered trademark) Low Energy), but is not limited to this. In addition to or instead of short-range wireless communication, the remote control 170 may also be communicably connected via a communication network or the like.

[0092] A plurality of remote controls 170 may be provided. That is, the controller 100 may be able to acquire location information of each remote control 170 from a plurality of remote controls 170. The remote control 170 may be attachable to the seedling transplanter 1.

[0093] The controller 100 controls the speed of the engine 30 and the trunnion opening of the HST 14, thereby controlling the vehicle speed of the traveling vehicle body 2.

[0094] The controller 100 sets the vehicle speed mode to the first vehicle speed mode or the second vehicle speed mode in accordance with the operation of the setting switch 49. That is, the controller 100 sets the trunnion opening of the HST 14 to the first upper limit opening or the second upper limit opening in accordance with the operation state of the setting switch 49.

[0095] When the vehicle speed mode is the first vehicle speed mode, the controller 100 controls the trunnion opening of the HST 14 in accordance with the position (operation amount) of the main transmission operation lever 36 so that the vehicle speed of the traveling vehicle body 2 becomes a vehicle speed according to the position of the main transmission operation lever 36. The controller 100 controls the trunnion opening of the HST 14 while setting the trunnion opening of the HST 14 to a first upper limit opening.

[0096] When the vehicle speed mode is the second vehicle speed mode, the controller 100 restricts the trunnion opening of the HST 14 to the second upper limit opening. As a result, the vehicle speed of the traveling vehicle body 2 is limited to a lower vehicle speed compared to when the vehicle speed mode is the first vehicle speed mode. The rotation speed of the engine 30 is set according to the position of the main shift operation lever 36.

[0097] The relationship between the position of the main transmission control lever 36, the trunnion opening, and the rotation speed of the engine 30 when the vehicle speed mode is the second vehicle speed mode will be described with reference to FIG. 7. FIG. 7 is a diagram showing the relationship between the position of the main transmission control lever 36, the trunnion opening, and the rotation speed of the engine 30. For the sake of explanation, FIG. 7 plots the trunnion opening and the rotation speed of the engine 30 on the vertical axis. FIG. 7 also shows the position of the main transmission control lever 36 between the neutral region 812 (see FIG. 4) and the forward travel region 811 (see FIG. 4). FIG. 7 also shows a portion of the trunnion opening in the first vehicle speed mode with a dashed line.

[0098] When the vehicle speed mode is the first vehicle speed mode, the trunnion opening degree increases as the position of the main transmission operation lever 36 moves from the neutral region 812 to the frontmost side of the forward travel region 811. Also, the rotation speed of the engine 30 increases.

[0099] On the other hand, when the vehicle speed mode is the second vehicle speed mode, if the position of the main transmission operation lever 36 moves from the neutral region 812 to the frontmost side of the forward travel region 811, the trunnion opening is restricted to the second upper limit opening. Note that because the rotation speed of the engine 30 increases, the vehicle speed of the traveling vehicle body 2 also changes in accordance with changes in the rotation speed of the engine 30; however, because the trunnion opening is restricted to the second upper limit opening, an increase in the vehicle speed of the traveling vehicle body 2 is suppressed more than when the vehicle speed mode is the first vehicle speed mode. In other words, in the second vehicle speed mode, the trunnion opening is restricted, so the vehicle speed of the traveling vehicle body 2 does not increase due to the trunnion opening, but as the rotation speed of the engine 30 increases, the vehicle speed of the traveling vehicle body 2 increases slightly.

[0100] In this way, when the vehicle speed mode is the second vehicle speed mode, the trunnion opening is restricted to the second upper limit opening, thereby suppressing the vehicle speed of the traveling body 2. For example, when the main speed change lever 36 is in the forward most position in the forward traveling area 811 and the vehicle speed mode is the first vehicle speed mode, the seedling transplanter 1 can achieve high-speed traveling according to the position of the main speed change lever 36. When the main speed change lever 36 is in the forward most position in the forward traveling area 811 and the vehicle speed mode is the second vehicle speed mode, the seedling transplanter 1 can achieve low-speed traveling with the trunnion opening restricted.

[0101] Next, the process for setting the upper limit of the trunnion opening degree according to the embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the process for setting the upper limit of the trunnion opening degree according to the embodiment.

[0102] The controller 100 determines whether the setting switch 49 is in the first position (S100). If the setting switch 49 is in the first position (S100: Yes), the controller 100 sets the upper limit of the trunnion opening to the first upper limit (S101).

[0103] If the setting switch 49 is not at the first position (S100: No), that is, if the setting switch 49 is at the second position, the controller 100 sets the upper limit of the trunnion opening to the second upper limit (S102).

[0104] The seedling transplanter 1 includes an engine 30, an HST 14, a main speed change control lever 36, a setting switch 49, and a controller 100. The engine 30 is mounted on the traveling body 2. The HST 14 changes the speed of the power input from the engine 30 and outputs it. The main speed change control lever 36 can adjust the trunnion opening of the HST 14, thereby adjusting the speed of the traveling body 2. The setting switch 49 accepts an operation to change the upper limit of the trunnion opening of the HST 14 using the main speed change control lever 36. The controller 100 sets the upper limit of the trunnion opening depending on the operating state of the setting switch 49.

[0105] This allows the seedling transplanter 1 to change the upper limit of the trunnion opening in response to the operation of the setting switch 49. For example, when the seedling transplanter 1 is being loaded onto a truck or otherwise moved on an inclined surface, the upper limit of the trunnion opening can be reduced to suppress the speed of the traveling body 2 and allow fine adjustments to be made regarding the travel of the traveling body 2. Therefore, the seedling transplanter 1 can improve the safety of the operator.

[0106] The main speed change operation lever 36 can also switch between forward and reverse travel of the traveling vehicle body 2. The controller 100 sets the upper limit of the trunnion opening when the traveling vehicle body 2 is traveling forward and when it is traveling backward, in accordance with the operation of the setting switch 49. The rotation speed of the engine 30 is set by the amount of operation of the main speed change operation lever 36.

[0107] This allows the seedling transplanter 1 to set appropriate upper limit trunnion opening degrees for forward and reverse travel. Therefore, the seedling transplanter 1 can make fine adjustments to the travel of the traveling body 2 when traveling forward and reverse, improving operator safety. Furthermore, by setting the engine 30 rotation speed according to the amount of operation of the main transmission operating lever 36, the seedling transplanter 1 can, for example, increase the engine 30 rotation speed on an inclined surface while regulating the trunnion opening degree, thereby stabilizing the travel of the traveling body 2.

[0108] Furthermore, the controller 100 sets the vehicle speed mode to a first vehicle speed mode in which the upper limit opening degree is a first upper limit opening degree, or a second vehicle speed mode in which the upper limit opening degree is a second upper limit opening degree, in accordance with the operation of the main transmission operation lever 36. The second vehicle speed mode is a mode in which the speed of the traveling vehicle body 2 is slower than in the first vehicle speed mode.

[0109] As a result, by setting the vehicle speed mode to the second vehicle speed mode, the seedling transplanter 1 can prevent the trunnion opening from becoming too large, thereby improving the safety of the operator.

[0110] The first upper limit opening degree and the second upper limit opening degree are different opening degrees when the traveling vehicle body 2 is moving forward and when it is moving backward. The second upper limit opening degree when moving backward in the second vehicle speed mode is smaller than the second upper limit opening degree when moving forward in the second vehicle speed mode.

[0111] As a result, the seedling transplanter 1 can further improve the safety of the operator when moving backward.

[0112] When the vehicle speed mode is changed from the second vehicle speed mode to the first vehicle speed mode, the seedling transplanter 1 according to the modified example cancels the second vehicle speed mode on the condition that the main speed change operation lever 36 is in the neutral region 812. For example, if the main speed change operation lever 36 is not in the neutral region 812, the vehicle speed mode is maintained in the second vehicle speed mode even if the setting switch 49 is operated from the second position to the first position.

[0113] As a result, the seedling transplanter 1 can suppress a sudden increase in speed of the traveling body 2 when the upper limit of the trunnion opening increases from the second upper limit to the first upper limit, thereby improving the safety of the operator.

[0114] The seedling transplanter 1 according to the modified example may operate in the second vehicle speed mode on the condition that the seedling planting device 55 is in a predetermined non-ground working state. For example, when the seedling planting device 55 is in a working state, even if the setting switch 49 is operated from the first position to the second position, the vehicle speed mode does not change to the second vehicle speed mode, but remains in the first vehicle speed mode.

[0115] As a result, the seedling transplanter 1 prevents the vehicle speed mode from switching to the second vehicle speed mode when the seedling planting device 55 is in an operating state. When the vehicle speed mode is switched to the second vehicle speed mode, it is assumed that the traveling body 2 will travel on a slope, for example, when being loaded onto a truck. In such a case, if the seedling planting device 55 is in an operating state, the seedling planting device 55 may hit the slope and deteriorate. The seedling transplanter 1 can prevent deterioration of the seedling planting device 55 by switching to the second vehicle speed mode, provided that the seedling transplanter 1 is in a predetermined non-ground operating state.

[0116] The seedling transplanter 1 according to the modified example may execute the second vehicle speed mode on the condition that the float 62 is not in contact with the ground. The seedling transplanter 1 according to the modified example may execute the second vehicle speed mode on the condition that the auxiliary speed change lever 37 is in the planting position.

[0117] The seedling transplanter 1 according to the modified example controls the speed of the traveling body 2 by controlling the output of the HST 14 and the rotation speed of the engine 30 through operation of either the main speed change lever 36 or the accelerator pedal 110. The seedling transplanter 1 also controls the rotation speed of the engine 30 through operation of the other of the main speed change lever 36 and the accelerator pedal 110. When the vehicle speed mode is set to the second vehicle speed mode in response to operation of the setting switch 49, the upper limit of the output of the HST 14 is set through operation of the main speed change lever 36 and the accelerator pedal 110.

[0118] As a result, the seedling transplanter 1 can control the output of the HST 14 and the RPM of the engine 30 by operating either the main speed change lever 36 or the accelerator pedal 110, and can also control the RPM of the engine 30 by operating the other of the main speed change lever 36 and the accelerator pedal 110. Therefore, since the controlled objects are different depending on the operation of the main speed change lever 36 and the accelerator pedal 110, the controlled objects that the operator desires to control can be differentiated depending on the operation of the main speed change lever 36 and the accelerator pedal 110. Therefore, the seedling transplanter 1 can improve the operator's maneuverability. Furthermore, when the vehicle speed mode is the second vehicle speed mode, the output of the HST 14 can be regulated by the operation of the main speed change lever 36 and the accelerator pedal 110, thereby improving the safety of the operator.

[0119] The seedling transplanter 1 according to the modified example may set the vehicle speed mode based on the tilt angle of the traveling vehicle body 2 in the front-rear direction detected by the tilt sensor 92.

[0120] For example, when the tilt angle detected by the tilt sensor 92 is equal to or greater than a first predetermined angle (predetermined angle), the controller 100 sets the vehicle speed mode to the second vehicle speed mode. That is, when the tilt angle is equal to or greater than the first predetermined angle, the controller 100 automatically sets the upper limit of the trunnion opening to the second upper limit. The first predetermined angle is a preset angle at which it can be determined that the traveling vehicle body 2 is on an inclined surface.

[0121] Furthermore, when the vehicle speed mode is the second vehicle speed mode and the tilt angle becomes less than the first predetermined angle, the controller 100 maintains the vehicle speed mode in the second vehicle speed mode. That is, when the vehicle speed mode is the second vehicle speed mode, the controller 100 maintains the vehicle speed mode in the second vehicle speed mode even if the tilt angle becomes small and becomes less than the first predetermined angle.

[0122] The controller 100 cancels the second vehicle speed mode when the vehicle speed mode is in the second vehicle speed mode and the main shift operation lever 36 enters the neutral region 812 or when the accelerator pedal 110 is released. In other words, when the vehicle speed mode is in the second vehicle speed mode and the main shift operation lever 36 enters the neutral region 812 or when the accelerator pedal 110 is released, the vehicle speed mode is changed from the second vehicle speed mode to the first vehicle speed mode.

[0123] As a result, when the inclination angle becomes equal to or greater than the first predetermined angle, the seedling transplanter 1 switches the vehicle speed mode to the second vehicle speed mode, thereby setting the upper limit of the trunnion opening to the second upper limit when traveling on an inclined surface, thereby improving the safety of the operator. Also, when the main transmission operation lever 36 is in the neutral region 812 or the accelerator pedal 110 is no longer operated, the seedling transplanter 1 switches the vehicle speed mode to the first vehicle speed mode, thereby suppressing a sudden increase in the speed of the traveling vehicle body 2 and improving the safety of the operator.

[0124] The first predetermined angle may be changeable. The first predetermined angle can be set by an operator or the like. This allows the operator to set the first predetermined angle according to an inclined surface, such as the angle of a running board used when loading the seedling transplanter 1 onto a truck. For example, the first predetermined angle may be set in 0.1 degree increments up to 15 degrees.

[0125] The controller 100 of the seedling transplanter 1 according to the modified example may have an angle setting mode for setting a first predetermined angle. The ON / OFF state of the angle setting mode is set by the operator. The seedling transplanter 1 is equipped with a switch for switching between angle setting modes. When the angle setting mode is ON, the controller 100 sets the angle measured by the tilt sensor 92 when the traveling body 2 enters a field as the first predetermined angle. For example, the controller 100 determines whether the traveling body 2 has entered a field based on position information detected by the position detection device 150. Furthermore, when the angle setting mode is ON and the traveling body 2 moves from a slope to flat ground, the controller 100 may set the angle on the slope to the first predetermined angle.

[0126] This allows the seedling transplanter 1 to set the first predetermined angle in accordance with the field.

[0127] In the seedling transplanter 1 according to the modified example, when a work area is set by traveling along the ridges of a field (paths La, Lb, Lc) as shown in FIG. 9, the orientation of the path La during travel may be set as the orientation of the reference line in the work area. FIG. 9 is a diagram showing an example of a method for setting the work area. The work area is an area in which work can be performed, for example, by autonomous traveling, i.e., by straight-line assist and turning assist.

[0128] The controller 100 of the seedling transplanter 1 according to the modified example deletes the reference data for automatic travel when the travel mode is automatic travel mode and the tilt angle is equal to or greater than a first predetermined angle. The reference data includes information on the orientation of the reference line, the straight travel path that serves as the reference for automatic straight travel in the field, the travel distance of the process where the work was performed, and position information related to the process where the work was performed.

[0129] This allows the seedling transplanter 1 to automatically delete the reference data for the field where the work was performed when the work in the field is completed and the seedling transplanter 1 is removed from the field, thereby preventing the seedling transplanter 1 from automatically traveling in another field using incorrect reference data.

[0130] The seedling transplanter 1 according to the modified example may change the trunnion opening so that the torque is low and the rotation speed of the engine 30 is high when the vehicle speed mode is the second vehicle speed mode and the tilt angle is equal to or greater than the second predetermined angle. For example, the seedling transplanter 1 reduces the trunnion opening.

[0131] When the vehicle speed mode is changed to the first vehicle speed mode or the second vehicle speed mode, the seedling transplanter 1 according to the modified example may be changed to the first vehicle speed mode or the second vehicle speed mode via a transition preparation mode, respectively. This allows the seedling transplanter 1 to suppress abrupt changes in vehicle speed when the vehicle speed mode is switched.

[0132] For example, when the vehicle speed mode is changed from the second vehicle speed mode to the first vehicle speed mode, the vehicle speed is regulated in the transition preparation mode in the same manner as in the second vehicle speed mode, and the vehicle speed mode is changed to the first vehicle speed mode under certain conditions. The certain conditions are, for example, when the main transmission operation lever 36 is in the neutral region 812. The certain conditions are when the seedling planting unit 4 is not in the predetermined lowered position.

[0133] Furthermore, when the vehicle speed mode is changed from the first vehicle speed mode to the second vehicle speed mode, there is no restriction on the vehicle speed in the transition preparation mode, and the vehicle speed mode is changed to the second vehicle speed mode under certain conditions. The specific conditions are, for example, when the main transmission operation lever 36 is in the neutral region 812. The specific conditions are when the auxiliary transmission operation lever 37 is in a position that corresponds to the planting speed.

[0134] When changing the vehicle speed mode, the seedling transplanter 1 according to the modified example may sound an alarm or display an indication on the monitor 86. In addition, the seedling transplanter 1 according to the modified example may turn on the lamp of the center mascot 66.

[0135] In the seedling transplanter 1 of the modified example, the vehicle speed mode may be set to the second vehicle speed mode when the setting switch 49 is in the second position, the main speed change operating lever 36 is in the neutral region 812, the sub-speed change operating lever 37 is at planting speed, the planting clutch 27a is in the disengaged state, the float 62 is in a non-grounded state, and the safety switch is OFF (for example, the stop pedal is not depressed).

[0136] In the seedling transplanter 1 of the modified example, when the vehicle speed mode is the second vehicle speed mode, the setting switch 49 is in the first position, the main shift operating lever 36 is in the neutral region 812, and the trunnion of the HST 14 is in the neutral position, the vehicle speed mode may be set to the first vehicle speed mode.

[0137] The seedling transplanter 1 according to the modified example may be configured not to accept an operation to engage the planting clutch 27a when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may be configured not to accept an operation to raise the seedling planting unit 4 when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may be configured not to accept an operation to lower the seedling planting unit 4 when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may be configured not to accept a control to raise the seedling planting unit 4 when the traveling body 2 moves backward when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may be configured not to accept a control to slightly lower the seedling planting unit 4 when the vehicle speed mode is the second vehicle speed mode.

[0138] In the seedling transplanter 1 according to the modified example, the HST 14 may be set to the neutral position when the main speed change operation lever 36 or the sub-speed change operation lever 37 is operated. This makes it possible to prevent the seedling transplanter 1 from suddenly starting due to erroneous operation.

[0139] In the seedling transplanter 1 according to the modified example, the vehicle speed mode may be set to the second vehicle speed mode when a slow speed switch different from the setting switch 49 is ON, the main speed change operating lever 36 is in the neutral region 812, and the machine is not in tight-fitting control, not in tight-fitting planting control, not in straight-line assist, and not in turning assist.

[0140] The seedling transplanter 1 according to the modified example may not perform the tightly packed planting control when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may not perform the tightly packed planting control when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may not perform the straight-line assist control when the vehicle speed mode is the second vehicle speed mode. The seedling transplanter 1 according to the modified example may not perform the turning assist control when the vehicle speed mode is the second vehicle speed mode.

[0141] In the seedling transplanter 1 according to the modified example, when the ultra-low speed switch is OFF and the main speed change operation lever 36 is in the neutral region 812, the vehicle speed mode may be set to the first vehicle speed mode.

[0142] The seedling transplanter 1 according to the modified example may emit a warning sound using a buzzer or the like when the vehicle speed mode is the second vehicle speed mode and the target vehicle speed set by the main speed change operation lever 36 during forward movement exceeds 20% of the vehicle speed in the first vehicle speed mode. The seedling transplanter 1 according to the modified example may be able to change the vehicle speed restriction when the vehicle speed mode is the second vehicle speed mode on the setting screen of the monitor 86.

[0143] The seedling transplanter 1 according to the modified example may emit a warning sound using a buzzer or the like when the vehicle speed mode is the second vehicle speed mode and the target vehicle speed set by the main shift lever 36 during reverse travel exceeds 30% of the vehicle speed in the first vehicle speed mode. The seedling transplanter 1 according to the modified example may be able to change the vehicle speed restriction when the vehicle speed mode is the second vehicle speed mode on the setting screen of the monitor 86.

[0144] The seedling transplanter 1 according to the modified example may be configured to set the vehicle speed mode to the second vehicle speed mode while the slow speed switch is being pressed.

[0145] The seedling transplanter 1 according to the modified example may be provided with a forward slow speed switch and a reverse slow speed switch. The seedling transplanter 1 according to the modified example may set the HST 14 to the neutral position when neither the forward slow speed switch nor the reverse slow speed switch is pressed. The seedling transplanter 1 according to the modified example may set the HST 14 to the neutral position when both the forward slow speed switch and the reverse slow speed switch are pressed.

[0146] In the seedling transplanter 1 according to the modified example, when the HST motor 146 is operated to the acceleration side by operating the ultra-low speed switch, the response of the HST motor 146 may be made to accelerate less (slower) than during normal lever operation.

[0147] In the seedling transplanter 1 according to the modified example, when the HST 14 is in the neutral position, the response of the HST motor 146 may be accelerated less (slower) than during normal lever operation.

[0148] The seedling transplanter 1 according to the modified example may increase the rotation speed of the engine 30 in accordance with the trunnion opening of the HST 14. For example, the seedling transplanter 1 controls the rotation speed of the engine 30 not only in accordance with the position of the main transmission operating lever 36, but also in accordance with the trunnion opening of the HST 14.

[0149] As a result, when the vehicle speed mode is the second vehicle speed mode, the seedling transplanter 1 prevents the rotation speed of the engine 30 from becoming too high, making it possible to fine-tune the vehicle speed.

[0150] Further advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0151] 1. Seedling transplanter (work vehicle) 2 Running vehicle 4. Seedling planting section (working equipment) 14 HST (Continuously Variable Transmission, Hydraulic Continuously Variable Transmission) 30 Engine 35 Steering wheel (steering device) 36 Main speed change operating lever (operating device, first operating device) 49 Setting switch (setting tool) 55 Seedling planting device 92 Inclination Sensor 95 Steering motor (motor) 100 Controller (control device) 110 Accelerator pedal (operating device, second operating device) 150 Position detection device (position information acquisition device)

Claims

1. an engine provided in a traveling vehicle body; a hydraulic continuously variable transmission that changes the speed of power input from the engine and outputs the power; an operating tool that can adjust the vehicle speed of the traveling vehicle body by adjusting the trunnion opening degree of the hydraulic continuously variable transmission; a setting tool that accepts a change operation of an upper limit opening degree of a trunnion opening degree of the hydraulic continuously variable transmission device by the operating tool; an inclination sensor for detecting an inclination angle in the longitudinal direction of the traveling vehicle body; a control device that sets an upper limit of the trunnion opening degree in accordance with the operating state of the setting tool; Equipped with The control device sets the vehicle speed mode to a first vehicle speed mode in which the upper limit opening degree is a first upper limit opening degree or a second vehicle speed mode in which the upper limit opening degree is a second upper limit opening degree in response to an operation of the setting tool, The second vehicle speed mode is a mode in which the speed of the traveling vehicle body is slower than that of the first vehicle speed mode, the control device sets the vehicle speed mode to the second vehicle speed mode when the tilt angle is equal to or greater than a predetermined angle; The predetermined angle is changeable in the work vehicle.

2. The operating tool can switch between forward and backward movement of the traveling vehicle body, the control device sets an upper limit opening degree of the trunnion opening degree when the traveling vehicle body is moving forward and when the traveling vehicle body is moving backward in response to an operation of the setting tool, The work vehicle according to claim 1 , wherein the engine speed is set according to the amount of operation of the operating tool.

3. the first upper limit opening degree and the second upper limit opening degree are different opening degrees when the traveling vehicle body is moving forward and when the traveling vehicle body is moving backward, The work vehicle according to claim 1 , wherein the second upper limit opening degree when traveling backward in the second vehicle speed mode is smaller than the second upper limit opening degree when traveling forward in the second vehicle speed mode.

4. A work vehicle as described in claim 1, wherein the control device cancels the second vehicle speed mode when the setting device is operated from a second position corresponding to the second vehicle speed mode to a first position corresponding to the first vehicle speed mode, provided that the operating device is in a neutral position.

5. The operating tool is a first operating tool that stops at a position where no operation by an operator is performed; a second operating tool that returns to its initial position when no longer operated by the operator; Including, The control device an output of the hydraulic continuously variable transmission and a rotation speed of the engine are controlled by operating either the first operating tool or the second operating tool, thereby controlling the speed of the traveling vehicle body; The rotation speed of the engine is controlled by operating the other of the first operating tool and the second operating tool, 2. The work vehicle according to claim 1, wherein, when the vehicle speed mode is set to the second vehicle speed mode in response to operation of the setting device, an upper limit of the output of the hydraulic continuously variable transmission device is set in response to operation of the first operating device or the second operating device, and the output of the hydraulic continuously variable transmission device is regulated.

6. a work device provided on the traveling vehicle body so as to be able to rise and fall and used for field work; Equipped with 2. The work vehicle according to claim 1, wherein when the setting tool is operated from a first position corresponding to the first vehicle speed mode to a second position corresponding to the second vehicle speed mode, the control device executes the second vehicle speed mode on the condition that the work implement is in a predetermined non-ground work state.

7. an inclination sensor for detecting an inclination angle in the longitudinal direction of the traveling vehicle body; Equipped with The control device If the tilt angle is equal to or greater than a predetermined angle, the vehicle speed mode is set to the second vehicle speed mode; When the vehicle speed mode is the second vehicle speed mode and the tilt angle becomes less than the predetermined angle, the vehicle speed mode is maintained in the second vehicle speed mode, The work vehicle according to claim 1 , wherein the second vehicle speed mode is cancelled when the operating tool is in a neutral position or in an unoperated state while the vehicle speed mode is in the second vehicle speed mode.

8. A position information acquisition device for acquiring position information of the traveling vehicle body, the control device has an angle setting mode for setting the predetermined angle, 8. The work vehicle according to claim 1, wherein when the control device is in the angle setting mode and the traveling vehicle body enters a field based on the position information, the control device sets the predetermined angle to an angle measured when the traveling vehicle body enters the field.

9. a steering device provided on the traveling vehicle body; a position information acquisition device for acquiring position information of the traveling vehicle body; When the traveling mode of the traveling vehicle body is an automatic traveling mode, a motor that drives the steering device; Equipped with The control device When the driving mode is the automatic driving mode, the motor is controlled based on the position information. If the tilt angle is equal to or greater than the predetermined angle, the reference data for automatic driving is deleted; 8. The work vehicle according to claim 1, wherein the reference data includes at least one of the orientation of a reference line, information regarding a straight-line route that serves as a reference for automatic straight-line driving in a field, a travel distance of a process in which work was performed, and position information regarding the process in which work was performed.

Images