Work vehicle

Abstract

To accelerate and decelerate a vehicle according to a driver's intention.SOLUTION: A work vehicle comprises: a main transmission device which performs continuously variable transmission of a vehicle; a main transmission lever which, when the main transmission device is activated, is operated from a neutral position to either an acceleration side or a deceleration side; a main transmission lever sensor which detects an operational position of the main transmission lever; and a control section which outputs a transmission instruction value corresponding to the operation position of the main transmission lever detected by the main transmission lever sensor to the main transmission device. The main transmission lever is energized so that the lever, after being tilted, returns to the neutral position. The control section is capable of storing the transmission instruction value corresponding to the operation position of the main transmission lever and performing constant-speed control to enable the vehicle to travel at a fixed travel speed corresponding to the stored transmission instruction value. The control section initiates the continuously variable transmission when the main transmission lever has been tilted for a predetermined period or longer.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Conventionally, there is known a work vehicle equipped with a continuously variable transmission that controls the acceleration (speed increase) and deceleration during vehicle speed change depending on the operation speed and amount of the main speed change lever when the main speed change lever is operated to change the vehicle speed continuously (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-298050 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, agricultural work vehicles such as tractors often travel at a constant speed (constant speed) while working, so a so-called memory speed change is being considered, in which a predetermined speed is stored and the speed is changed so that the vehicle travels at the constant speed stored.

[0005] For example, when memory shifting is performed in a conventional work vehicle such as the one described above, the actual vehicle speed (vehicle speed during constant speed driving) and the position of the main shift lever may not match during memory shifting, which may cause confusion for the driver.

[0006] For this reason, in order to prevent discrepancies between the actual vehicle speed during memory shifting and the position of the main shift lever, a technology is being considered in which the driver shifts to the faster side when the main shift lever is pushed forward, the speed is shifted to the slower side when the driver pushes the main shift lever backward, and the main shift lever is returned to neutral while maintaining a predetermined constant speed when the driver releases the main shift lever.

[0007] However, even with this technology, there is a possibility that the vehicle may suddenly accelerate or decelerate if, for example, the driver unintentionally touches the main shift lever during memory shifting. Therefore, there is room for improvement in terms of accelerating or decelerating the vehicle through the driver's intended operation, rather than accelerating or decelerating the vehicle due to an incorrect operation by the driver, i.e., accelerating or decelerating the vehicle as intended by the driver.

[0008] The present invention has been made in view of the above, and has an object to provide a work vehicle that can accelerate and decelerate the vehicle body as intended by the driver. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, the work vehicle (1) according to the embodiment includes a main transmission (30) that continuously changes the speed of the vehicle body, and a neutral position (P N ) to either the forward speed increasing side or the rearward speed decreasing side, a main speed changing lever sensor (61) that detects the operating position (P) of the main speed changing lever (15), and a control unit (100) that outputs a speed change command value corresponding to the operating position (P) of the main speed changing lever (15) detected by the main speed changing lever sensor (61) to the main speed changing device (30) to change the speed of the machine body continuously. After the main speed changing lever (15) is tilted, the main speed changing lever (15) is moved to a neutral position (P N ), and the control unit (100) stores a speed change command value corresponding to the operating position (P) of the tilted main speed change lever (15), and is capable of performing constant speed travel control to make the machine travel at a constant speed at the travel speed of the stored speed change command value, and when the tilted main speed change lever (15) has been tilted for a predetermined time or more, the control unit (100) starts infinitely variable speed change of the machine. [Effects of the Invention]

[0010] According to the work vehicle of this embodiment, the vehicle can accelerate and decelerate as intended by the driver. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic side view showing a work vehicle according to an embodiment. [Figure 2] FIG. 2 is a diagram (part 1) showing the configuration of the transmission. [Figure 3] FIG. 3 is a diagram (part 2) showing the configuration of the transmission. [Figure 4] FIG. 4 is an explanatory diagram of the constant speed cruise control. [Figure 5] FIG. 5 is a diagram showing the operating positions of the main speed change lever. [Figure 6] FIG. 6 is a diagram showing the amount of operation of the main speed change lever. [Figure 7] FIG. 7 is a diagram showing the relationship between the operation amount and operation time of the main speed change lever and the degree of acceleration / deceleration. [Figure 8] FIG. 8 is a flowchart showing an example of a processing procedure for gear shift control by the control unit. [Figure 9] FIG. 9 is an explanatory diagram of the behavior of the tractor in response to basic operations of the main speed change lever. [Figure 10] FIG. 10 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern A-1 shown in FIG. [Figure 11] FIG. 11 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern A-2 shown in FIG. [Figure 12] FIG. 12 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern B-1 shown in FIG. [Figure 13] FIG. 13 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern B-2 shown in FIG. [Figure 14] FIG. 14 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern C-1 shown in FIG. [Figure 15] FIG. 15 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern C-2 shown in FIG. [Figure 16] FIG. 16 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern D-1 shown in FIG. [Figure 17] FIG. 17 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern D-2 shown in FIG. [Figure 18] FIG. 18 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern E-1 shown in FIG. [Figure 19] FIG. 19 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern E-2 shown in FIG. [Figure 20] FIG. 20 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern F-1 shown in FIG. [Figure 21] FIG. 21 is a diagram showing the relationship between the tractor speed, the operation position of the main speed change lever, and the tilt time of the main speed change lever in the basic operation pattern F-2 shown in FIG. [Figure 22] FIG. 22 is an explanatory diagram of the behavior of the tractor in response to the combined operations of the main speed change lever. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the work vehicle disclosed in the present application will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below.

[0013] <Overview of the work vehicle> An overview of a work vehicle 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic side view showing a work vehicle 1 according to an embodiment.

[0014] In addition, each figure may show a three-dimensional Cartesian coordinate system including a Z-axis whose positive direction is vertically upward (upward). For ease of explanation, the positive direction of the X-axis will be defined as the left, the negative direction of the X-axis as the right, the positive direction of the Y-axis as the forward direction, and the negative direction of the Y-axis as the backward direction, and the X-axis direction will be referred to as the left-right direction, the Y-axis direction as the front-back direction, and the Z-axis direction as the up-down direction.

[0015] In addition, the tractor 1, which is an example of a work vehicle, can travel on roads and fields using the power of a prime mover such as an engine E, which is the drive source, and can perform specified tasks in the field by detachably attaching multiple types of work implements (not shown) that each perform ground work.

[0016] In the following description, the work vehicle (tractor) 1 may be referred to as the "machine body."

[0017] As shown in Figure 1, the tractor 1 is equipped with an engine E mounted inside a hood 2 at the front of the vehicle body. Rotational power from the engine E is transmitted to a transmission 3, which is a transmission including a main transmission 30 (described later), and is then reduced in speed by the transmission 3 before being transmitted to the running wheels, i.e., the front wheels 4 and rear wheels 5 of the tractor 1.

[0018] A driver's seat 7 is provided in a cabin 6 at the rear of the aircraft. A steering wheel 8 for steering the front wheels 4 is provided in front of the driver's seat 7. A meter panel 9 and the like are provided in front of the steering wheel 8.

[0019] A work implement such as a rotary work implement is connected to the rear of the body of the tractor 1. The work implement is driven by a PTO (Power Take-Off) shaft 150 that protrudes rearward from a casing (transmission case) of the transmission 3.

[0020] In addition, around the driver's seat 7 within the cabin 6, in addition to a steering wheel 8 and a meter panel 9, various operating pedals such as an accelerator pedal 10, a clutch pedal 11, and a brake pedal 12, various operating levers such as a forward / reverse lever 14, a main shift lever 15, and an auxiliary shift lever (not shown), and various operating devices (not shown) are provided.

[0021] The forward / reverse lever 14 is an operating tool that is operated to operate a forward / reverse clutch 43 (see FIG. 3), which is a forward / reverse device that switches the vehicle between "forward," "neutral," and "reverse." The main speed change lever 15 is an operating tool that is operated to operate a main speed change device 30 that changes the vehicle's traveling speed (also called vehicle speed). The main speed change lever 15 is set in the neutral position P N (See Figure 5) to move to the speed increasing or decreasing side.

[0022] The tractor 1 can perform automatic gear shifting by controlling the transmission 3 according to the rotation speed of the engine E. Furthermore, as will be described later, the tractor 1 can also switch the main gear simply by operating the accelerator pedal 10 or the main gear shift lever 15.

[0023] <Transmission configuration> The power transmission configuration of the work vehicle 1 according to this embodiment will be described with reference to Figures 2 and 3. Figures 2 and 3 are diagrams (power transmission diagrams) showing the configuration of the transmission 3.

[0024] The tractor 1 is equipped with a hydrostatic continuously variable transmission (hereinafter referred to as HST (Hydro Static Transmission)) 31 equipped with a hydraulic pump 311 and a hydraulic motor 312, and a hydromechanical continuously variable transmission (hereinafter referred to as HMT (Hydro Mechanical Transmission)) 30 combined with a planetary gear (planetary gear mechanism 33).

[0025] The main transmission, HMT30, combines the HST31 and planetary gear mechanism 33, making it possible to start, accelerate (increase speed), and decelerate the machine with only lever or pedal operation, and also enables the machine to travel with higher transmission efficiency than a transmission configuration with only the HST31. Furthermore, when combined with electronic control, the HMT30 enables constant speed traveling, which allows the machine to travel at a constant speed (constant speed).

[0026] 2 and 3, in the transmission 3, the HST 31 includes a variable displacement hydraulic pump 311 and a fixed displacement hydraulic motor 312. The hydraulic pump 311 and the hydraulic motor 312 are housed in a housing (not shown) of the HST 31. A pump output shaft 32 is inserted into the hydraulic pump 311 along the rotation axis of the hydraulic pump 311. The pump output shaft 32 transmits power from the engine E to the hydraulic pump 311, the planetary gear mechanism 33, and the PTO shaft 150.

[0027] The transmission 3 is housed in a transmission case (not shown). In addition to the pump output shaft 32, the transmission 3 is provided with a motor output shaft 34, an output shaft 35, a sub-transmission shaft 37a, a PTO shaft 150, and other components that are rotatable. The transmission 3 is also provided with a planetary gear mechanism 33. The planetary gear mechanism 33 is disposed behind the HST 31 (downstream in the transmission direction). The planetary gear mechanism 33 includes a sun gear 331, a planetary gear 332, a ring gear 333, and a carrier 334.

[0028] A hydraulic clutch 36 is provided on the rear side (downstream side in the transmission direction) of the planetary gear mechanism 33. The hydraulic clutch 36 includes a front clutch 361 and a rear clutch 362. The hydraulic clutch 36 switches between HST mode and HMT mode. The hydraulic clutch 36 transmits power to the output shaft 35 in accordance with the two modes (HST mode and HMT mode), and transmits the power to the sub-transmission shaft 37a via the sub-transmission mechanism 37.

[0029] A pump-side input gear 38 is provided on the pump output shaft 32. The pump-side input gear 38 meshes with a gear 334a of a carrier 334 that is loosely fitted concentrically with the sun gear 331, thereby driving the carrier 334 to rotate. The carrier 334 is provided with a plurality of planet gears 332 that mesh with the sun gear 331 and the ring gear 333. In this way, the planetary gear mechanism 33 is made up of the sun gear 331, the plurality of planet gears 332, the ring gear 333, the carrier 334, etc.

[0030] In the planetary gear mechanism 33, the sun gear 331 is loosely fitted to the output shaft 35, and the planetary gear 332 meshes with the sun gear 331 and the ring gear 333. The planetary gear 332 is rotatably supported by a carrier 334 that is loosely fitted to the output shaft 35, and is configured to revolve around the sun gear 331 while rotating on its own axis.

[0031] A motor-side input gear 39 is provided on the motor output shaft 34. The motor-side input gear 39 drives the sun gear 331 to rotate.

[0032] The auxiliary transmission mechanism 37 transmits power to an auxiliary transmission shaft 37a when the auxiliary transmission clutch is engaged. The auxiliary transmission shaft 37a is configured to be able to transmit power to a rear wheel differential 40 via a pinion provided on the auxiliary transmission shaft 37a. The auxiliary transmission shaft 37a is also configured to be able to drive the front wheels 4 via a front wheel speed increase switching mechanism 41 and a front wheel differential 42.

[0033] Here, the transmission configurations in the HST mode and the HMT mode will be described. As shown in Figure 3, in the HMT mode, the front clutch 361 of the hydraulic clutch 36 is engaged and the rear clutch 362 is disengaged.

[0034] At this time, the sun gear 331 of the planetary gear mechanism 33 is rotationally driven by the rotational power of the pump output shaft 32. Due to the rotation of the sun gear 331, the rotation of the carrier 334 and the sun gear 331 is combined and transmitted to the planetary gear 332. The power transmitted to the sun gear 331 is transmitted to the ring gear 333.

[0035] In the HMT mode, the front clutch 361 of the hydraulic clutch 36 is controlled to be connected, and the rotational power of the ring gear 333 is transmitted to the output shaft 35. The power of the output shaft 35 is transmitted to the rear wheels 5 and the front wheels 4 via the auxiliary transmission mechanism 37.

[0036] On the other hand, in the HST mode, the rear clutch 362 of the hydraulic clutch 36 is engaged and the front clutch 361 is disengaged. In the HST mode, the rotational power of the motor output shaft 34 is transmitted to the output shaft 35. The power of the output shaft 35 is transmitted to the rear wheels 5 and the front wheels 4 via the auxiliary transmission mechanism 37.

[0037] In the HST mode, the rotational power of the engine E is transmitted to the rear wheels 5 and the front wheels 4 without passing through the planetary gear mechanism 33. That is, the power of the engine E rotates the carrier 334 via the pump output shaft 32, but since the carrier 334 simply rotates idle, the power is changed in speed by the HST 31 and transmitted from the motor output shaft 34 to the output shaft 35, and then transmitted to the rear wheels 5 and the front wheels 4 via the sub-transmission mechanism 37.

[0038] As shown in Fig. 3, the tractor 1 (see Fig. 1) includes a control unit 100. When the main speed change lever 15 is operated, the control unit 100 outputs a speed change command value corresponding to the operation position P (see Fig. 5) of the main speed change lever 15 to the HMT 30, which is the main transmission. In this way, the HMT 30 is controlled by the control unit 100.

[0039] The control unit 100 is a computer equipped with a processing device such as a CPU (Central Processing Unit), a storage device such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an HDD (Hard Disk Drive), and further an input / output device.

[0040] The control unit 100 includes a driving system ECU (Electronic Control Unit) that controls the driving system, an engine ECU as an engine control unit that controls the engine E, and a work implement lifting system ECU that controls the lifting and lowering of a work implement such as a rotary tiller.

[0041] Connected to the control unit 100 are an electronic governor (actuator) 51 that controls the rotation speed of the engine E, a sensor 52 that detects the rotation speed of the engine E (output shaft of the engine E), and a main shift lever sensor 61 that detects the operating position (also referred to as the shift position) P (see FIG. 5) of the main shift lever 15. Note that the main shift lever sensor 61 can be, for example, a potentiometer that detects the rotation (tilting) angle of the main shift lever 15. Therefore, the main shift lever sensor 60 can detect the tilt angle of the main shift lever 15.

[0042] In addition, the control unit 100 is connected to a forward / reverse lever sensor 71 that detects the operating position of the forward / reverse lever 14, a sensor 53 that detects the rotational speed of the motor output shaft 34, a speed change actuator 54 that controls the swash plate of the hydraulic pump 311, and solenoid valves 55, 56 that connect / disconnect the hydraulic clutch 36.

[0043] In this way, by electrically connecting sensors 52, 53, etc., the control unit 100 feedback controls the inclination angle of the movable swash plate of the hydraulic pump 311 via the shift actuator 54 based on the operating position P of the main shift lever 15 and the detection values ​​of sensors 52, 53 so that the traveling speed (vehicle speed) of the tractor 1 becomes the shift command value corresponding to the operating position P of the main shift lever 15.

[0044] In the gear shift control of the control unit 100, for example, the HMT mode is executed in the medium to high speed range, and the HST mode is executed in the low speed range, and two driving modes are automatically switched in accordance with the gear shift command value.

[0045] The forward / reverse lever 14 is operated to operate a forward / reverse clutch 43, which is a forward / reverse device. The forward / reverse clutch 43 switches the vehicle between "forward", "reverse" and "neutral". The control unit 100 can control the forward / reverse clutch 43.

[0046] When the forward / reverse lever sensor 71 detects that the operational position of the forward / reverse lever 14 is "forward," the control unit 100 controls the speed change actuator so that the movable swash plate of the hydraulic pump 311 is within the range of the forward position. When the control unit 100 detects that the operational position of the forward / reverse lever 14 is "reverse," the control unit 100 controls the speed change actuator so that the movable swash plate of the hydraulic pump 311 is within the range of the reverse position.

[0047] Furthermore, when the control unit 100 detects that the operating position of the forward / reverse lever 14 is "neutral," it controls the speed change actuator to hold the movable swash plate of the hydraulic pump 311 in the neutral position, thereby preventing rotation of the output shaft 35. Note that the forward / reverse lever sensor 71 may be, for example, a potentiometer that detects the rotation angle of the forward / reverse lever 14, or a switch having contacts that correspond to the respective positions of "forward," "reverse," and "neutral."

[0048] 3, a gear shift memory switch 62 that is operated to store the operating position P of the main shift lever 15 is connected to the control unit 100. The gear shift memory switch 62 is operated by the driver of the tractor 1 or the like when storing the operating position P of the main shift lever 15 detected by the main shift lever sensor 61.

[0049] As described above, the control unit 100 outputs to the HMT 30 a gear shift command value corresponding to the operating position P of the main shift lever 15. When the main shift lever 15 is operated, the control unit 100 changes the gear shift command value output to the HMT 30 in accordance with the operating position P of the main shift lever 15.

[0050] Here, the tractor 1 (see FIG. 1) is capable of constant speed traveling at a vehicle speed specified by the driver. For this reason, the control unit 100 performs constant speed traveling control to make the tractor 1 travel at a constant speed. By the control unit 100 performing constant speed traveling control, the tractor 1 travels at a constant speed specified by the main shift lever 15 and stored by the control unit 100. This constant speed traveling control is also called memory speed change control.

[0051] <Constant speed cruise control (part 1)> The constant speed traveling control will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram of the constant speed traveling control, and is a flowchart showing a general processing procedure performed by the control unit 100 during the constant speed traveling control.

[0052] When constant speed cruise control is performed, the control unit 100 (see FIG. 3) acquires the operation position P (see FIG. 5) when the driver tilts the main shift lever 15 (see FIG. 3), and stores a gear change command value corresponding to the operation position P of the main shift lever 15 (step S101). The control unit 100 may store the operation position P of the main shift lever 15. The control unit 100 acquires the operation position P of the main shift lever 15 from the detection value of the main shift lever sensor 61 (see FIG. 3).

[0053] The control unit 100 outputs the gear change instruction value stored in the processing of step S101 to the HMT 30 (see Figure 2), and starts constant speed traveling of the vehicle at the speed (vehicle speed) of the gear change instruction value corresponding to the operating position P of the main gear change lever 15 (step S102).

[0054] Thereafter, the control unit 100 terminates the constant speed traveling control (step S104) in response to an operation by the driver to terminate the constant speed traveling (step S103). The operation to terminate the constant speed traveling control may be, for example, an operation of a separately provided constant speed traveling cancel switch.

[0055] <Main gear shift lever> The main speed change lever 15 will be described with reference to Figures 5 to 7. Figure 5 is a diagram showing the operation position P of the main speed change lever 15. Figure 6 is a diagram showing the operation amount of the main speed change lever 15. Figure 7 is a diagram showing the relationship between the operation amount and operation time of the main speed change lever 15 and the degree of acceleration / deceleration.

[0056] The main shift lever 15 is an operating tool (operating lever) operated by the driver, and is located on either the left or right side of the driver's seat 7 (see FIG. 1). The main shift lever 15 is provided so that it can be tilted forward or backward. The main shift lever 15 may be provided, for example, on an armrest around the driver's seat 7. The main shift lever 15 may also be provided, for example, on a lever guide.

[0057] As shown in FIG. 5, the main speed change lever 15 is in the neutral position P N When the aircraft is tilted forward from the neutral position P N When the main speed change lever 15 is tilted backward from the neutral position P N When the aircraft is tilted forward from the neutral position P N When the vehicle is tilted backward from the neutral position P, the vehicle slows down, allowing the driver to operate the vehicle in a way that suits his or her senses. N The further away from the aircraft is towards the front or rear, the greater the speed increase or decrease.

[0058] The main speed change lever 15 is in the neutral position P N The maximum speed-up position P (maximum speed-up position P H ) and the neutral position P N From the rear of the aircraft, the maximum deceleration operation position P (maximum deceleration position P L ) and can be tilted up to.

[0059] After the main shift lever 15 is operated, if the driver releases his / her hand from the main shift lever 15 or releases the force applied to the main shift lever 15, the main shift lever 15 returns to the neutral position P N To return to the neutral position P NThe main speed change lever 15 is biased toward the neutral position P by a predetermined biasing force F of a biasing member such as a spring. N The pressure is biased to the side.

[0060] The main speed change lever 15 has a neutral position P N A predetermined dead zone A is set on the front side (i.e., the speed increasing side) and rear side (i.e., the speed decreasing side) of the main shift lever 15. By setting the dead zone A in the main shift lever 15 in this way, the driver can perform an operation that suits his or her senses.

[0061] In addition, in the tractor 1 (see FIG. 1), when the main speed change lever 15 is operated forward (to increase speed) or backward (to decrease speed), the speed increase or decrease of the tractor 1 changes at a constant rate. For example, the speed increase or decrease of the tractor 1 changes proportionally (linearly). When the main speed change lever 15 is in the neutral position P N When the main speed change lever 15 is tilted from the neutral position P to the speed-up side, the aircraft speed increases according to the amount of operation (in this case, the amount of tilt, i.e., the degree of tilt), and the main speed change lever 15 returns to the neutral position P N When tilted from the up position to the deceleration position, the aircraft will decelerate according to the amount of tilt.

[0062] That is, in the tractor 1, by holding the main speed change lever 15 forward (to the speed increase side) for a certain period of time or more, the speed of the machine can be increased to the maximum speed. Also, in the tractor 1, by holding the main speed change lever 15 backward (to the speed decrease side) for a certain period of time or more, the speed of the machine can be increased to the minimum speed. The minimum speed of the machine is, for example, creep speed. Note that the minimum speed of the machine may also be, for example, a stop (zero speed).

[0063] The main speed change lever 15 is divided into a plurality of operation areas, each of which has a forward speed increase side and a rearward speed decrease side, and has a neutral position P N The main speed change lever 15 is set so that the acceleration or deceleration rate increases as the range becomes farther from the neutral position P N The first stage area is closer to the neutral position P NThe operation area is divided into two, the first area being the area farther from the first area, and the second area being the area farther from the first area, and the acceleration or deceleration rate is set to be greater in the second area than in the first area.

[0064] The main speed change lever 15 may be biased so that the biasing force F increases stepwise on both the speed increase side and the speed decrease side. In this case, the main speed change lever 15 is ... N The main shift lever 15 is biased by a first-stage biasing force from a predetermined operating amount to a predetermined operating amount, and when the operating amount increases beyond this operating amount, the main shift lever 15 is biased by a second-stage biasing force greater than the first stage. In this way, the main shift lever 15 may be biased so that the biasing force F increases in two stages on both the speed-up side and the speed-down side.

[0065] As shown in FIGS. 6 and 7, for example, when the main speed change lever 15 is in the neutral position P N When the main shift lever 15 is tilted 50% from the neutral position P to the forward side (speed increasing side), the vehicle speed increases to the maximum speed increasing value ("10" in the case of main shift stages "1" to "10") in 5 seconds. N When the vehicle is tilted 100% (maximum operation) from the left to the front (accelerating side), the vehicle speed increases to the maximum acceleration value ("10" in the case of main gear stages "1" to "10") in 1 second, for example.

[0066] In the case of deceleration, as in the case of speeding up, the main speed change lever 15 is in the neutral position P N When the main shift lever 15 is tilted 50% from the neutral position P to the rear (deceleration side), the vehicle speed is decelerated to the maximum deceleration value ("-10" in the case of main shift stages "-1" to "-10") in 5 seconds, for example. N When the vehicle is tilted 100% (maximum operation) from the left to the right (deceleration side), the vehicle speed is decelerated to the maximum deceleration value ("-10" in the case of main gear stages "-1" to "-10") in 1 second, for example.

[0067] <Constant speed cruise control (part 2)> The constant speed cruise control will be further explained. The control unit 100 changes the speed change command value output to the HMT 30 (see FIG. 3) according to the operation position P of the main speed change lever 15, and when the driver of the tractor 1 determines that the desired vehicle speed has been reached and releases his / her hand from the main speed change lever 15, the main speed change lever 15 is returned to the neutral position P. N , the main speed change lever 15 returns to the neutral position P N That is, the control unit 100 holds the gear shift command value corresponding to the operation position P before the main gear shift lever 15 returns to the neutral position P. N Tractor 1 is driven at a constant speed at the speed just before returning to (immediately before).

[0068] When performing constant speed traveling control, the control unit 100 stores a shift command value corresponding to the operating position P of the main shift lever 15 tilted by the driver of the tractor 1, and outputs the stored shift command value to the HMT 30 (see Figure 2) to start constant speed traveling of the vehicle at the speed (vehicle speed) of the operating position P of the main shift lever 15.

[0069] As described above, the tractor 1 is in the neutral position P N Therefore, when the driver releases the main shift lever 15, the main shift lever 15P N is the neutral position P N At this time, the gear shift command value is maintained. When the main gear shift lever 15 is in the neutral position P N Since the gear change command value is maintained even when the vehicle returns to , the driver feels as if he or she is operating the vehicle to increase or decrease speed during constant speed travel control. This reduces driver confusion caused by a discrepancy between the actual vehicle speed during constant speed travel and the operating position of the main gear change lever 15.

[0070] In addition, constant speed travel can be started by operating the main speed change lever 15 with the feeling of operating to increase the speed of the vehicle, which reduces confusion among the driver due to a discrepancy between the actual vehicle speed and the operating position P of the main speed change lever 15.

[0071] <Gear shift control> In addition to performing the constant speed cruise control described above, the control unit 100 can also perform the following gear change control. In this gear change control, when the driver tilts the main shift lever 15 and detects that the tilted main shift lever has been tilted for a predetermined time or longer, the control unit 100 determines that the driver intends to start a gear change and starts infinitely variable gear change of the vehicle. The tilt time of the main shift lever 15 can be detected based on a detection signal sent from the main shift lever sensor 61, for example.

[0072] With this configuration, the continuously variable speed change of the vehicle does not start until the tilt time of the main shift lever 15 reaches or exceeds a predetermined time. Therefore, the vehicle will not accelerate or decelerate due to an erroneous operation by the driver, such as when the driver unintentionally touches the main shift lever 15, but can be accelerated or decelerated by the driver's intended operation. In other words, the vehicle can be accelerated or decelerated as intended by the driver.

[0073] Fig. 8 is a flowchart showing an example of a processing procedure for speed change control by the control unit 100. Fig. 8 illustrates a case where the tractor 1 starts traveling from a stopped state.

[0074] As shown in FIG. 8, when the control unit 100 detects a tilting operation of the main shift lever 15 while the tractor 1 is stopped (step S201), it determines whether the tilting time of the tilted main shift lever 15 is equal to or longer than a predetermined first time T1 (for example, approximately 0.5 seconds) (step S202).

[0075] When the control unit 100 determines in the processing of step S202 that the time is equal to or greater than the first time T1 (step S202: Yes), it starts the tractor 1 (step S203). After the tractor 1 starts, the control unit 100 increases the speed of the tractor 1 at a predetermined speed change rate, i.e., a predetermined acceleration (speed increase) rate, up to a preset target starting speed (step S204).

[0076] If the control unit 100 determines in the process of step S202 that the time is less than the first time T1 (step S202: No), the process returns to before the process of step S201. In this case, the control unit 100 determines that the driver has made an erroneous operation.

[0077] Thereafter, the control unit 100 causes the tractor 1 to travel at a predetermined vehicle speed (step S205). If a tilting operation of the main shift lever 15 is detected while the tractor 1 is traveling (step S206), the control unit 100 determines whether the tilting time of the main shift lever 15 is equal to or longer than a predetermined second time T2 (step S207). The second time T2 is longer than the first time T1.

[0078] If the control unit 100 determines in the process of step S207 that the time is equal to or greater than the second time T2 (step S207: Yes), it performs infinitely variable speed change of the tractor 1 according to the tilt time of the main speed change lever 15 (step S208).

[0079] If the control unit 100 determines in the processing of step S207 that the time is less than the second time T2 (step S207: No), it determines whether the time is equal to or greater than the first time T1 (step S209). If the control unit 100 determines in the processing of step S209 that the time is equal to or greater than the first time T1 (step S209: Yes), in other words, if it determines that the time is equal to or greater than the first time T1 and less than the second time T2, it increases the speed of the tractor 1 so that the vehicle speed becomes a predetermined vehicle speed, that is, so that the vehicle speed becomes the vehicle speed of the stored gear change instruction value (step S210).

[0080] If the control unit 100 determines in the process of step S209 that the time is less than the first time T1 (step S209: No), the process returns to before the process of step S206. In this case, the control unit 100 determines that the driver has made an erroneous operation.

[0081] After the processes of steps S208 and S210, the control unit 100 ends this gear shift control.

[0082] With this configuration, the vehicle will not start moving when it is stopped unless the tilt time of main shift lever 15 is equal to or longer than first time T1. Therefore, the vehicle will not start moving due to an erroneous operation by the driver, such as when the driver unintentionally touches main shift lever 15, but can start moving with the operation intended by the driver. In other words, the vehicle can be started as intended by the driver.

[0083] Furthermore, after the vehicle starts moving, the vehicle is accelerated to the target starting speed at a predetermined speed change rate, allowing the vehicle to smoothly accelerate to the target starting speed through the driver's intended operation.

[0084] Furthermore, when the main shift lever 15 is tilted while the vehicle is traveling, if the tilting time of the tilted main shift lever 15 is equal to or longer than the second time T2, the vehicle's speed is infinitely variable in accordance with this tilting time, thereby enabling the vehicle to accelerate or decelerate as intended by the driver. Furthermore, by infinitely variable speed changing of the vehicle not only in accordance with the operation amount of the main shift lever 15 (the amount of tilt, i.e., the degree of tilt) but also in accordance with the tilting time of the main shift lever 15, it is possible to achieve gear change control with reduced traveling shock.

[0085] Furthermore, when the main speed change lever 15 is tilted while the vehicle is traveling, if the tilted time of the main speed change lever is equal to or longer than the first time and shorter than the second time, the vehicle speed is increased to a predetermined speed, thereby enabling the vehicle to be accelerated or decelerated by the driver's intended operation.

[0086] In addition to performing the above-described speed change control, the control unit 100 can also perform the following forward / reverse control based on the operation of the forward / reverse lever 14. In this forward / reverse control, the control unit 100 causes the tractor 1 to speed up in reverse when the main speed change lever 15 is tilted forward (to increase speed) with the forward / reverse lever 14 tilted rearward from the neutral position to the reverse side. In addition, the control unit 100 causes the tractor 1 to slow down in reverse when the main speed change lever 15 is tilted rearward (to decrease speed) with the forward / reverse lever 14 tilted rearward to the reverse side.

[0087] Furthermore, even if the main shift lever 15 is tilted backward (toward the deceleration side) while the tractor 1 is stopped with the forward / reverse lever 14 tilted backward to the reverse side, the control unit 100 maintains the stop of the tractor 1. In this case, the tractor 1 will not start moving forward unless the forward / reverse lever 14 is switched to the forward position.

[0088] With this configuration, the driver can switch between forward and reverse travel of the vehicle without confusion because the vehicle is switched between forward and reverse travel using only the forward / reverse lever 14. Also, by tilting the main shift lever 15 rearward, the driver can avoid feeling uncomfortable when starting backward or accelerating while traveling in reverse.

[0089] The tractor 1 may be configured to eliminate the forward / reverse lever 14 and switch between forward and reverse movement of the machine body using the main speed change lever 15. With such a configuration, the machine body can be moved forward or backward or increased or decreased speed with a simple operation. In this case, when the main speed change lever 15 is tilted forward while the tractor 1 is stopped, the tractor 1 starts moving forward, and when the main speed change lever 15 is tilted backward, the tractor 1 starts moving backward.

[0090] In this case, when the main speed change lever 15 is tilted backward while the tractor 1 is moving backward, the speed of the tractor 1 increases, and when the main speed change lever 15 is tilted forward, the speed of the tractor 1 decreases. Furthermore, if the main speed change lever 15 remains tilted forward after the tractor 1 has stopped moving, the tractor 1 will start moving forward.

[0091] Furthermore, when the main speed change lever 15 is tilted forward while the tractor 1 is moving forward, the tractor 1 is decelerated. After the tractor 1 has stopped traveling, when the main speed change lever 15 is returned to neutral and then tilted further backward, the tractor 1 begins to move in reverse. With this configuration, by requiring the main speed change lever 15 to be returned to neutral once, the driver can clearly recognize the operation to switch between forward and reverse travel.

[0092] Furthermore, when the main speed change lever 15 is tilted backward while the tractor 1 is moving in reverse, the speed of the tractor 1 increases, and when the main speed change lever 15 is tilted forward, the speed of the tractor 1 decreases. After the tractor 1 has stopped traveling, when the main speed change lever 15 is returned to neutral and then tilted further forward, the tractor 1 starts moving forward. With this configuration, by requiring the main speed change lever 15 to be returned to neutral once, the driver can clearly recognize the operation to switch between forward and reverse travel.

[0093] Fig. 9 is an explanatory diagram (table) of the behavior of the tractor 1 in response to the basic operation of the main speed change lever 15. Figs. 10 to 21 are diagrams (graphs) showing the relationship between the vehicle speed of the tractor 1, the operation position P of the main speed change lever 15, and the tilt time of the main speed change lever 15 for each of the multiple basic operation patterns shown in Fig. 9.

[0094] As shown in Figure 9, the tractor 1 behaves according to each of a number of basic operation patterns of the main shift lever 15 via the main transmission (HMT) 30. Pattern A-1 occurs when, while the tractor 1 is stopped, the main shift lever 15 is tilted forward (to the first position on the speed-up side) (see Figure 5), and the tilt time of the main shift lever 15 is equal to or longer than a first time T1 and shorter than a second time T2. As shown in Figures 9 and 10, in pattern A-1, the tractor 1 begins to move forward in the direction of travel. In this case, the starting speed of the tractor 1 is set to the target starting speed.

[0095] As shown in Figure 9, pattern A-2 occurs when the main shift lever 15 is tilted forward (to the first position on the speed-up side) while the tractor 1 is traveling, and the tilt time of the main shift lever 15 is equal to or longer than the first or second time T2. As shown in Figures 9 and 11, in pattern A-2, the tractor 1 accelerates without any shock in the traveling direction. In addition, in pattern A-2, the tractor 1 can accelerate slowly.

[0096] As shown in Figure 9, pattern B-1 occurs when the main shift lever 15 is tilted forward (to the second position on the speed-up side) (see Figure 5) while the tractor 1 is stopped, and the tilt time of the main shift lever 15 is equal to or longer than the first time T1 and shorter than the second time T2. As shown in Figures 9 and 12, in pattern B-1, the tractor 1 begins to move forward. In this case, the starting speed of the tractor 1 is a preset target starting speed.

[0097] As shown in Figure 9, pattern B-2 occurs when the main shift lever 15 is tilted forward (to the second position on the speed-increasing side) while the tractor 1 is traveling, and the tilt time of the main shift lever 15 is equal to or longer than the first or second time T2. As shown in Figures 9 and 13, in pattern A-2, the tractor 1 accelerates without any traveling shock in the direction of travel. Also, in pattern A-2, the tractor 1 accelerates more than in the first position.

[0098] As shown in Fig. 9, pattern C-1 is a case where the main shift lever 15 is tilted backward (to the first position on the deceleration side) while the tractor 1 is stopped, and the tilt time of the main shift lever 15 is not determined. As shown in Figs. 9 and 14, in pattern C-1, the tractor 1 remains stopped.

[0099] As shown in Figure 9, pattern C-2 occurs when the main shift lever 15 is tilted backward (to the first position on the deceleration side) while the tractor 1 is traveling, and the tilt time of the main shift lever 15 is equal to or longer than the second time T2. As shown in Figures 9 and 15, in pattern C-2, the tractor 1 decelerates without any shock in the forward direction. In addition, in pattern C-2, the tractor 1 stops traveling.

[0100] As shown in Fig. 9, pattern D-1 is a case where the main shift lever 15 is tilted to the second position rearward (deceleration side) while the tractor 1 is stopped, and the tilting time of the main shift lever 15 is not determined. As shown in Figs. 9 and 16, in pattern D-1, the tractor 1 remains stopped.

[0101] As shown in FIG. 9, pattern D-2 occurs when the main shift lever 15 is tilted backward (to the first position on the deceleration side) while the tractor 1 is traveling, and the tilt time of the main shift lever 15 is equal to or longer than the second time T2. As shown in FIGS. 9 and 17, in pattern D-2, the tractor 1 decelerates without any traveling shock in the forward direction. In addition, in pattern D-2, the tractor 1 decelerates more than in the first position. In addition, in pattern D-2, the tractor 1 stops traveling.

[0102] As shown in Fig. 9, pattern E-1 is a case where, while the tractor 1 is stopped, the main shift lever 15 is tilted forward (to the speed-increasing side) and then immediately returned, and the tilting time of the main shift lever 15 is less than the first time T1. As shown in Figs. 9 and 18, in pattern E-1, the tractor 1 remains stopped.

[0103] As shown in Fig. 9, pattern E-2 is a case where, while the tractor 1 is traveling, the main shift lever 15 is tilted forward (to the speed-increasing side) and then immediately returned, and the tilting time of the main shift lever 15 is equal to or longer than the first time T1 and shorter than the second time T2. As shown in Figs. 9 and 19, in pattern E-2, the tractor 1 gradually increases its speed in the direction of travel by a predetermined amount (for example, +2 km / h).

[0104] As shown in Fig. 9, pattern F-1 is a case where, while the tractor 1 is stopped, the main shift lever 15 is tilted rearward (toward deceleration) and then immediately returned, and the tilting time of the main shift lever 15 is not determined. As shown in Figs. 9 and 20, in pattern F-1, the tractor 1 remains stopped.

[0105] As shown in Fig. 9, pattern F-2 is a case where, while the tractor 1 is traveling, the main shift lever 15 is tilted forward (to the speed-increasing side) and then immediately returned, and the tilting time of the main shift lever 15 is equal to or longer than the first time T1 and shorter than the second time T2. As shown in Figs. 9 and 21, in pattern F-2, the tractor 1 decelerates in a stepwise manner by a predetermined speed (for example, -2 km / h) in the traveling direction.

[0106] As shown in Fig. 9, pattern G-1 is the case when the three-point linkage raising button provided on the main shift lever 15 is pressed. In pattern G-1, when the three-point linkage raising button is pressed, three-point linkage raising (maximum raising) is executed.

[0107] As shown in Fig. 9, pattern G-2 is the case when the three-point link lowering button provided on the main shift lever 15 is pressed. In pattern G-2, when the three-point link lowering button is pressed, three-point link lowering (lowest position) is executed.

[0108] As shown in Figure 9, pattern H-1 is the case when a function button that allows any registered function to be selected is provided on the main shift lever 15 and this function button is pressed. In pattern H-1, when the function button is pressed, the function registered in the function button is executed.

[0109] As shown in Figure 9, pattern H-2 occurs when multiple function buttons, each of which can be selected from a registered function, are provided on the main shift lever 15 and these function buttons are pressed. In pattern H-2, when each of the multiple function buttons is pressed, the function registered to that button is executed.

[0110] FIG. 22 is an explanatory diagram (table) of the behavior of the tractor 1 in response to the combined operations of the main speed change lever 15.

[0111] As shown in Figure 22, pattern I-1 is a case where the tractor 1 has a D mode in which the main shift lever 15 is placed in D (drive) range and the tractor 1 automatically shifts gears up to the maximum speed simply by depressing the accelerator pedal, and the main shift lever 15 is tilted forward or backward while the tractor 1 is stopped in D mode. In pattern I-1, the D mode takes priority, and operation of the main shift lever 15 is not accepted.

[0112] As shown in Figure 22, pattern I-2 occurs when the main shift lever 15 is tilted forward or backward while the tractor 1 is traveling in D mode. In pattern I-2, priority is given to D mode, and operation of the main shift lever 15 is not accepted.

[0113] As shown in Figure 22, pattern J-1 is a case where the main shift lever 15 is tilted forward while the tractor 1 is stopped and cruise control (constant speed control) is operating. In pattern J-1, cruise control is not activated.

[0114] As shown in Figure 22, pattern J-2 is a case where the main shift lever 15 is tilted forward while the tractor 1 is traveling with cruise control activated, and the tilting time of the main shift lever 15 is equal to or longer than the first time T1. In pattern J-2, the cruise control is released, and the vehicle speed at the time of release is set as the target vehicle speed (the speed at which acceleration / deceleration by tilting the main shift lever 15 begins).

[0115] The above-described embodiment realizes the following work vehicle 1.

[0116] (1) A main transmission 30 that continuously changes the speed of the aircraft, and a neutral position P N a main speed change lever sensor 61 that detects the operation position P of the main speed change lever 15; and a control unit 100 that outputs a speed change command value corresponding to the operation position P of the main speed change lever 15 detected by the main speed change lever sensor 61 to the main transmission 30 to continuously change the speed of the vehicle. After the main speed change lever 15 is tilted, the main speed change lever 15 is tilted to the neutral position P. N The control unit 100 stores a speed change command value corresponding to the operating position of the tilted main speed change lever 15, and is capable of performing constant speed travel control to travel the vehicle at a constant speed at the travel speed of the stored speed change command value, and when the tilted main speed change lever 15 is tilted for a predetermined time or more, the control unit 100 starts infinitely variable speed change of the vehicle.

[0117] With this type of work vehicle 1, continuously variable speed change of the vehicle does not begin until the tilt time of the main shift lever 15 reaches or exceeds a predetermined time. Therefore, the vehicle will not accelerate or decelerate due to an erroneous operation by the driver, such as when the driver unintentionally touches the main shift lever 15, but can be accelerated or decelerated by an operation intended by the driver. In other words, the vehicle can be accelerated or decelerated as intended by the driver.

[0118] In addition, when the main speed change lever 15 is in the neutral position P N Therefore, when the driver releases the main shift lever 15, the main shift lever 15 returns to the neutral position and the shift command value is maintained. N Since the gear change command value is maintained even when the vehicle returns to , the driver feels as if he or she is operating the vehicle to increase or decrease speed during constant speed cruise control. This reduces driver confusion caused by a discrepancy between the actual vehicle speed during constant speed cruise control and the operating position P of the main shift lever 15.

[0119] (2) In (1) above, when the main shift lever 15 is tilted while the vehicle is stopped, the control unit 100 starts the vehicle if the tilting time of the tilted main shift lever 15 is equal to or longer than a predetermined first time T1.

[0120] In addition to the effect of (1) above, such a work vehicle 1 does not allow the vehicle to start when it is stopped unless the tilt time of the main shift lever 15 is equal to or longer than a predetermined first time T1. Therefore, the vehicle will not start due to an erroneous operation by the driver, such as when the driver unintentionally touches the main shift lever 15, but can be started by the operation intended by the driver. In other words, the vehicle can be started as intended by the driver.

[0121] (3) In the work vehicle 1 described above in (2), after the vehicle starts moving, the control unit 100 increases the speed of the vehicle at a predetermined speed change rate up to a preset starting speed.

[0122] In addition to the effect of (2) above, such a work vehicle 1 allows the vehicle to smoothly accelerate up to a target starting speed through an operation intended by the driver.

[0123] (4) In the above (3), when the main shift lever 15 is tilted while the vehicle is traveling, the control unit 100 continuously changes the speed of the vehicle in accordance with the tilting time of the tilted main shift lever 15 if the tilting time is equal to or longer than a predetermined second time T2 that is longer than the first time T1.

[0124] In addition to the effect of (3) above, such a work vehicle 1 allows the vehicle to accelerate or decelerate according to the driver's intended operation.

[0125] (5) In (4) above, when the main shift lever 15 is tilted while the vehicle is traveling, the control unit 100 increases the speed of the vehicle so that it reaches a predetermined traveling speed if the tilting time of the tilted main shift lever 15 is equal to or longer than the first time T1 and shorter than the second time T2.

[0126] In addition to the effect of (4) above, such a work vehicle 1 allows the vehicle to accelerate or decelerate according to the driver's intended operation.

[0127] (6) In the above (5), a forward / reverse device 43 is provided for switching between forward, reverse and neutral positions of the aircraft, and when the forward / reverse device 43 is operated, the neutral position P N The work vehicle 1 is equipped with a forward / reverse lever 14 that is tilted from the front to either the forward side or the reverse side, and a forward / reverse lever sensor 71 that detects the operating position of the forward / reverse lever 14, and the control unit 100 increases the speed of the vehicle in reverse when the main speed change lever 15 is tilted forward with the forward / reverse lever 14 tilted to the reverse side, and decreases the speed of the vehicle in reverse when the main speed change lever 15 is tilted rearward with the forward / reverse lever 14 tilted to the reverse side, and maintains the vehicle stopped even if the main speed change lever 15 is tilted rearward while the vehicle is stopped.

[0128] In addition to the effect of (5) above, such a work vehicle 1 allows the vehicle to be switched between forward and reverse using only the forward / reverse lever 14, so the driver can switch between forward and reverse without confusion.

[0129] 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]

[0130] 1. Work vehicle (tractor) 14 Forward / reverse lever 15 Main gear shift lever 30 Main Transmission (HMT) 43 Forward / reverse device (forward / reverse clutch) 61 Main shift lever sensor 71 Forward / reverse lever sensor 100 control section P operation position P N neutral position T1 1st Hour T2 2nd Hour

Claims

1. A main transmission that continuously changes the speed of the aircraft; a main speed change lever that is tilted from a neutral position to either a forward speed increase side or a rearward speed decrease side when operating the main speed change device; a main speed change lever sensor that detects the operation position of the main speed change lever; a control unit that outputs a speed change command value corresponding to the operation position of the main speed change lever detected by the main speed change lever sensor to the main speed change device, thereby continuously changing the speed of the aircraft; Equipped with The main shift lever is After the main speed change lever is tilted, the tilted main speed change lever is biased to return to a neutral position, The control unit A speed change command value corresponding to the tilted operation position of the main speed change lever is stored, and constant speed travel control can be performed to travel the vehicle at a constant speed at the travel speed of the stored speed change command value, In this work vehicle, when the tilted main speed change lever is tilted for a predetermined time or longer, the continuously variable speed change of the vehicle body is started.

2. The control unit 2. The work vehicle according to claim 1, wherein when the main shift lever is tilted while the vehicle is stopped, the vehicle is started if the tilted time of the main shift lever is equal to or longer than a predetermined first time.

3. The control unit 3. The work vehicle according to claim 2, wherein after the vehicle starts moving, the vehicle speed is increased at a predetermined variable speed up to a preset starting speed.

4. The control unit 4. The work vehicle according to claim 3, wherein when the main shift lever is tilted while the vehicle is traveling, if the tilting time of the main shift lever is equal to or longer than a predetermined second time that is longer than the first time, the vehicle is continuously variable in accordance with the tilting time.

5. The control unit 5. The work vehicle according to claim 4, wherein, when the main shift lever is tilted while the vehicle is traveling, the vehicle is accelerated to a predetermined traveling speed if the tilted time of the main shift lever is equal to or longer than the first time and shorter than the second time.

6. a forward / reverse device for switching the forward, reverse and neutral positions of the aircraft; a forward / reverse lever that is tilted from a neutral position to either the forward side or the reverse side when operating the forward / reverse device; a forward / reverse lever sensor that detects the operation position of the forward / reverse lever; Equipped with The control unit 6. The work vehicle according to claim 5, wherein when the main shift lever is tilted forward with the forward / reverse lever tilted toward the reverse side, the vehicle speeds up in reverse, and when the main shift lever is tilted rearward with the forward / reverse lever tilted toward the reverse side, the vehicle speeds down in reverse, and the vehicle remains stopped even when the main shift lever is tilted rearward while the vehicle is stopped.

Images