Work vehicles

Abstract

To provide a work vehicle capable of selecting an appropriate shift position during start according to a speed limit state.SOLUTION: One aspect of the present disclosure is a work vehicle, comprising a transmission, and a controller including a processor. The controller determines whether a speed limit state of the work vehicle is in a first speed limit state or a second speed limit state that requires speed limit more than the first speed limit state, and when the speed limit state of the work vehicle is in the second speed limit state, limits a speed range that can be set as a speed range during start, which is a speed range that is applied when starting.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Some work vehicles such as motor graders and bulldozers have an automatic transmission having a plurality of speed stages. The automatic transmission of a work vehicle is controlled such that the speed stage is automatically switched according to the vehicle speed and load when performing operations such as land leveling and excavation, and when performing transportation by self-driving. For example, in the automatic transmission of a bulldozer described in Patent Document 1, the vehicle starts at the speed stage selected by the operator at the start, and then the speed stage is switched according to the vehicle speed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a work vehicle, for example, for facilitating operation during work, it may be provided with a driving mode that automatically performs steering. Further, it may be provided with a driving mode that can perform steering with a steering operation lever provided near the work implement lever without operating the steering wheel. In such a driving mode, the speed limit state during traveling of the work vehicle may be different from that in the normal driving mode. Thus, in a work vehicle having a plurality of driving modes with different speed limits, there has been a problem that it is desired that control be performed so that the vehicle switches to an appropriate speed stage according to the speed limit state even at the start.

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a work vehicle capable of selecting an appropriate starting shift position according to the speed limit state. [Means for solving the problem]

[0006] To solve the above problems, one aspect of the present disclosure is a work vehicle comprising a transmission and a controller including a processor, wherein the controller determines whether the speed restriction state of the work vehicle is a first speed restriction state or a second speed restriction state which requires a greater speed restriction than the first speed restriction state, and when the speed restriction state of the work vehicle is the second speed restriction state, the work vehicle restricts a speed range that can be set as a starting speed range which is a speed range applied when starting. [Effects of the Invention]

[0007] According to the embodiments of this disclosure, an appropriate starting shift position can be selected depending on the speed limit condition. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram showing the configuration of a work vehicle according to the embodiment. [Figure 2] This is a block diagram showing a functional configuration for controlling the operation of the transmission in a work vehicle according to an embodiment. [Figure 3] This figure shows an example of information display in a display device for a work vehicle according to the embodiment. [Figure 4] This figure shows an example of the shift position and shift index at startup, and the shift positions that can be selected for each driving mode, which are stored in the controller of the work vehicle according to the embodiment. [Figure 5] This diagram schematically shows the shift positions that can be selected as the starting shift position in the controller of the work vehicle according to the embodiment. [Figure 6] This figure shows an example of setting the shift position at startup when the driving mode is changed in the controller of a work vehicle according to the embodiment. [Figure 7] This is a flowchart showing the operation of the controller according to the embodiment. [Figure 8] This figure shows another example of setting the shift position at startup when the driving mode is changed in the controller of the work vehicle according to the embodiment. [Figure 9] This figure shows another example of setting the shift position at startup when the driving mode is changed in the controller of the work vehicle according to the embodiment. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or corresponding components are given the same reference numerals, and their descriptions will be omitted as appropriate.

[0010] Figure 1 is a schematic diagram showing the configuration of the work vehicle 10 according to the embodiment. As shown in Figure 1, the work vehicle 10 according to this embodiment is, for example, a motor grader. However, the work vehicle 10 may be something other than a motor grader, such as a wheeled excavator, bulldozer, or wheel loader.

[0011] The motor grader, which serves as the work vehicle 10 in this embodiment, mainly comprises a body frame 11, front wheels 12, rear wheels 13, a driver's cab 14, a work implement 15, a drive mechanism room 16, and a transmission 18.

[0012] The vehicle frame 11 extends along the longitudinal direction Da of the work vehicle 10. The vehicle frame 11 supports the driver's cab 14. The vehicle frame 11 has a rear frame 11r located behind the longitudinal direction Da and a front frame 11f located in front of the longitudinal direction Da. The rear frame 11r supports the drive unit 16. The front frame 11f is rotatably connected to the rear frame 11r.

[0013] The front wheels 12 and the rear wheels 13 are provided in front of and behind the vehicle body frame 11 in the front-rear direction Da, respectively. The front wheels 12 and the rear wheels 13 are respectively arranged on both sides in the width direction Dw of the work vehicle 10 that intersects the front-rear direction Da in the horizontal plane. The front wheels 12 are rotatably supported at the front end of the front frame 11f. The rear wheels 13 are provided, for example, in two sets on the rear frame 11r at intervals in the front-rear direction Da.

[0014] The working machine 15 includes, for example, a blade 152. The work vehicle 10 can perform operations such as land leveling work, snow removal work, light cutting, and material mixing with the blade 152, for example.

[0015] FIG. 2 is a block diagram showing a functional configuration for controlling the operation of the transmission 18 in the work vehicle according to the present embodiment. As shown in FIG. 2, the rear wheels 13 are rotationally driven by a drive machine 17 disposed in the drive machine room 16. The drive machine 17 is an engine. The drive machine 17 may be an electric motor. The driving force from the drive machine 17 is transmitted to the axle 13s of the rear wheels 13 via the transmission 18.

[0016] The transmission 18 changes the rotation output from the drive machine 17 and outputs it to the axle 13s. In the present embodiment, the transmission 18 is a stepped transmission that can switch the gear ratio (speed range) in multiple stages by switching the meshing state of a plurality of gears. Also, the transmission 18 may be a continuously variable transmission such as a so-called CVT (Continuously Variable Transmission) that can adjust the transmission ratio between the input side and the output side continuously.

[0017] The work vehicle 10 is configured to be able to move forward and backward in the longitudinal direction Da by rotating the rear wheels 13 via a transmission 18. The transmission 18 can switch the gear ratio in, for example, a plurality of stages (e.g., eight stages) of speed ranges (shift positions) in both forward and reverse. In this specification, when the transmission 18 is a stepped transmission, the region responsible for transmitting the driving force from the drive machine 17 to the axle 13s at each speed stage is referred to as a speed range. When the transmission 18 is a continuously variable transmission, the region responsible for transmitting the driving force from the drive machine 17 to the axle 13s at each speed stage pseudo-set in the continuously variable transmission is referred to as a speed range.

[0018] The transmission 18 switches the shift position according to the traveling speed of the work vehicle 10 detected by the speed sensor 19 during forward and reverse operations, respectively, under the control of the controller 30 described later. The transmission 18 performs shift position switching control such that the reduction ratio gradually decreases as the absolute value of the traveling speed of the work vehicle 10 increases. The transmission 18 switches the shift position by operating an electromagnetic control valve 18v such as a solenoid valve for performing a shifting operation under the control of the controller 30. <s

[0019] As shown in FIG. 1, the cab 14 is disposed at an intermediate portion in the longitudinal direction Da of the vehicle body frame 11. Inside the cab 14, as shown in FIG. 2, there are at least a steering wheel 21, a plurality of work implement levers 22, a steering operation lever 23, a forward / reverse (FNR) switching lever 24, a driving mode switching switch 25, an accelerator pedal 26, a shift lever (operating device) 28, a display device 29, and a controller 30.

[0020] The steering wheel 21 is disposed directly in front of the driver's seat (not shown) where the operator of the work vehicle 10 sits. The operator steers the front wheels 12 by rotating the steering wheel 21.

[0021] The multiple implement levers 22 are for operating the implement 15. The implement levers 22 are located on both the left and right (width direction) sides of the operator seated in the driver's seat. Each implement lever 22 is set to tilt in a direction such as the forward / backward direction or the left / right direction. By tilting each implement lever 22, the blade 152 of the implement 15 performs various actions such as vertical movement, forward / backward movement, left / right movement, and tilting. There are no limitations on the number or arrangement of the implement levers 22, or on the operation of the implement 15 when the implement levers 22 are operated.

[0022] The steering lever 23 is positioned near several work equipment levers 22. The operator steers the front wheels 12 by tilting the steering lever 23. The steering lever 23 allows the operator to steer the front wheels 12 without touching the steering wheel 21.

[0023] The forward / reverse selector lever 24 switches the direction of rotation of the rear wheels 13 to which the driving force of the drive unit 17 is transmitted, by operating the transmission 18, which will be described later. The forward / reverse selector lever 24 outputs a command to the transmission 18 to switch to one of the following positions based on the operator's operation: "Forward (F)" which transmits the driving force of the drive unit 17 to the rear wheels 13 so that the work vehicle 10 moves forward, "Neutral (N)" which cuts off the transmission of the driving force of the drive unit 17 to the rear wheels 13, or "Reverse (R)" which transmits the driving force of the drive unit 17 to the rear wheels 13 so that the work vehicle 10 moves backward. The accelerator pedal 26 adjusts the rotational speed of the drive unit 17 in accordance with the operator's input, thereby adjusting the travel speed of the work vehicle 10.

[0024] The driving mode selector switch 25 allows the operator to switch the driving mode of the work vehicle 10. In this embodiment, three driving modes are selectable for the work vehicle 10: "normal mode," "sub-steering mode," and "auto-steering mode."

[0025] In "normal mode," the operator steers the front wheels 12 by operating the steering wheel 21, and also controls the speed of the work vehicle 10 by operating the accelerator pedal 26, thereby driving the work vehicle 10.

[0026] In "sub-steering mode," the operator steers the front wheels 12 by tilting the steering lever 23, and also controls the speed of the work vehicle 10 by operating the accelerator pedal 26, thereby driving the work vehicle 10. In "sub-steering mode," the speed of the work vehicle 10 is limited. In "sub-steering mode," the controller 30, described later, controls the shift position that can be selected (set) in the transmission 18 when the work vehicle 10 starts moving.

[0027] In "Auto Steering Mode," the steering of the front wheels 12 is performed automatically by the control of the controller 30, which will be described later. In "Auto Steering Mode," the travel speed of the work vehicle 10 is limited. In "Auto Steering Mode," the shift position that can be selected (set) in the transmission 18 when the work vehicle 10 starts is limited by the control of the controller 30, which will be described later. In "Auto Steering Mode," the shift position that can be selected (set) when the work vehicle 10 starts is further limited than in "Sub Steering Mode," and the travel speed limit is set to an even lower speed.

[0028] In other words, in "Normal Mode," the system is set to a first speed limit state, where control functions requiring speed limits are disabled. In contrast, in "Sub-Steering Mode" and "Auto-Steering Mode," the system is set to a second speed limit state, where control functions requiring speed limits are enabled. In "Sub-Steering Mode" and "Auto-Steering Mode," the system is set to a second speed limit state, which requires a higher speed limit than the first speed limit state.

[0029] The shift lever 28 allows the operator to switch the shift position of the transmission 18. Normally, the shift lever 28 is positioned at "0 (zero)," which does not change the shift position of the transmission 18. The operator can switch the shift lever 28 to "UP," which raises the shift position of the transmission 18, or to "DOWN," which lowers the shift position. The controller 30, described later, switches the gear ratio of the transmission 18 according to the operator's operation of the shift lever 28 when the shift position is switched by that operation, and otherwise automatically switches the gear ratio of the transmission 18 according to the travel speed of the work vehicle 10. Note that the switching of the gear ratio of the transmission 18 may be performed only according to the operator's operation of the shift lever 28, and does not have to be performed automatically according to the travel speed of the work vehicle 10 by the controller 30. Furthermore, when the operator operates the shift lever 28 to start the work vehicle 10, the controller 30 switches the starting shift position of the transmission 18 in accordance with the operation of the shift lever 28.

[0030] Figure 3 shows an example of information displayed on the display device 29 of the work vehicle 10 in this embodiment. The display device 29 displays information related to multiple functions of the work vehicle 10. In this embodiment, as shown in Figure 3, the display device 29 displays information I1 indicating the starting shift position (starting speed range), which will be described in detail later.

[0031] (Example of controller configuration) The controller 30 controls the operation of the transmission 18. The controller 30 can be configured using a computer equipped with a processor such as a microcomputer or CPU (Central Processing Unit), and hardware such as peripheral circuits and peripheral devices for the computer. The controller 30 has a functional configuration consisting of a combination of hardware and software such as a program executed by the computer, and as shown in Figure 2, it includes an input / output unit 31, a setting condition storage unit 32, a state storage unit 33, a gear shift control unit 34, and a starting setting unit 35.

[0032] The input / output unit 31 repeatedly inputs operation information for the steering wheel 21, multiple work equipment levers 22, steering operation lever 23, forward / reverse selector lever 24, driving mode selector switch 25, and accelerator pedal 26 at predetermined intervals. Based on the processing of the transmission control unit 34 described later, the input / output unit 31 outputs command information for controlling the switching of the shift position of the transmission 18. The input / output unit 31 outputs image information, character information, etc. to be displayed on the display device 29.

[0033] The setting condition storage unit 32 stores various setting conditions used to control the transmission 18. For example, as shown in Figure 4, the setting condition storage unit 32 stores combinations of starting shift positions (starting speed ranges), which are the shift positions (speed ranges) when the work vehicle 10 starts moving forward (F) and in reverse (R), and shift indices S1 to S8, which are index values ​​indicating the combinations of starting shift positions, in association with each other. In this embodiment, the setting condition storage unit 32 is, for example, Forward 1st gear (F1) / Reverse 1st gear (R1): Shift index S1, Forward 1st gear (F1) / Reverse 2nd gear (R2): Shift index S2, Forward 1st gear (F1) / Reverse 3rd gear (R3): Shift index S3, Forward 2 gears (F2) / Reverse 2 gears (R2): Shift index S4, Forward 2nd gear (F2) / Reverse 3rd gear (R3): Shift index S5, 3 forward gears (F3) / 2 reverse gears (R2): Shift index S6, 3 forward gears (F3) / 3 reverse gears (R3): Shift index S7, 3 forward gears (F4) / 2 reverse gears (R2): Shift index S8, I remember it in association with that.

[0034] Furthermore, the setting condition storage unit 32 stores information indicating whether or not a combination of multiple starting shift position combinations (shift indices S1 to S8) shown in Figure 3 is selectable for each of the operating modes of the work vehicle 10: "normal mode," "sub-steering mode," and "auto-steering mode." In Figure 3, "○" indicates that the starting shift position is selectable in each operating mode, and "×" indicates that the starting shift position is not selectable. In this embodiment, in "normal mode," the vehicle is not subject to speed limit control that restricts the starting speed, and all shift indices S1 to S8 can be selected as the starting shift position. In "Sub-Steering Mode," shift index S8 is subject to speed limit control, and shift indices S1 to S7 can be selected as the starting shift position. In "Auto Steering Mode," shift indices S3, S5-S8 are subject to speed limit control, and only shift indices S1, S2, and S4 can be selected as the starting shift position.

[0035] The state memory unit 33 stores the operation information (operation status) of the steering wheel 21, multiple work equipment levers 22, steering operation lever 23, forward / reverse selector lever 24, driving mode selector switch 25, and accelerator pedal 26 that are input to the input / output unit 31. The state memory unit 33 temporarily stores the shift position set immediately before starting. In addition, if the shift position at starting is changed by the operator's operation of the shift lever 28, the state memory unit 33 stores the changed shift position at starting. In this embodiment, the state memory unit 33 stores the index value of the shift index corresponding to the shift position at starting.

[0036] The gear shift control unit 34 controls the operation of the electromagnetic control valve 18v to control the shift position switching operation of the transmission 18. When the work vehicle 10 starts moving, the gear shift control unit 34 switches the shift position (speed gear) of the transmission 18 according to the starting shift position set in the starting setting unit 35, which will be described later. After the work vehicle 10 starts moving, the gear shift control unit 34 changes the shift position of the transmission 18 according to the travel speed of the work vehicle 10 and the load of the work vehicle 10 detected by the speed sensor 19. The gear shift control unit 34 changes the shift position of the transmission 18 according to the travel speed of the work vehicle 10 and the load of the work vehicle 10 based on a pre-set gear shift control map, etc. The gear shift control unit 34 may change the shift position of the transmission 18 only according to the operation of the operator's shift lever 28, and may not change the shift position of the transmission 18 according to the travel speed of the work vehicle 10 and the load of the work vehicle 10. This does not specifically limit the details of the gear shift control of the transmission 18 by the gear shift control unit 34 after the work vehicle 10 has started.

[0037] The starting setting unit 35 sets the starting shift position according to the driving mode of the work vehicle 10 when the work vehicle 10 is started. The starting setting unit 35 sets the starting shift position based on the shift positions that can be selected as the starting shift position for each driving mode, which are stored in the setting condition storage unit 32 (see Figure 4).

[0038] The starting setting unit 35 executes the process of setting the starting shift position only when the work vehicle 10 is stopped. In this embodiment, the process of setting the starting shift position is executed only when the forward / reverse selector lever 24 is in the "neutral (N)" position and the work vehicle 10 is stopped. Here, a stopped state is when the travel speed of the work vehicle 10 detected by the speed sensor 19 is 0. In this embodiment, the travel speed of the work vehicle 10 is set to 0 if the speed sensor detects a speed of less than 1 km / h for 0.5 seconds or more.

[0039] As shown in Figures 4 and 5, the starting setting unit 35 selects one of the shift positions from shift indices S1 to S8 and sets it as the starting shift position when the driving mode of the work vehicle 10 is in "normal mode," which is a first speed limit state in which the control function requiring speed limiting is disabled. When the driving mode of the work vehicle 10 is in "sub-steering mode," which is a second speed limit state in which the control function requiring speed limiting is enabled, the starting setting unit 35 selects one of the shift positions from shift indices S1 to S7 and sets it as the starting shift position when the driving mode of the work vehicle 10 is in "auto-steering mode," which is a second speed limit state in which the control function requiring speed limiting is enabled, the starting setting unit 35 selects one of the shift positions from shift indices S1, S2, and S4 and sets it as the starting shift position when the driving mode of the work vehicle 10 is in "auto-steering mode," which is a second speed limit state in which the control function requiring speed limiting is enabled.

[0040] When the driving mode of the work vehicle 10 is changed, the starting shift position 35 sets a starting shift position according to the changed driving mode. For example, if the starting shift position set in "normal mode" is outside the shift positions that can be set in "sub-steering mode" or "auto-steering mode", the starting shift position 35 selects one of the shift positions that can be set in "sub-steering mode" or "auto-steering mode" and resets it as the starting shift position. Specifically, if the changed driving mode is "sub-steering mode", and the starting shift position set in "normal mode" immediately before the change was not one of the shift indices S1 to S7 that can be selected in "sub-steering mode", i.e., shift position F4 / R2 corresponding to shift index S8, the starting shift position 35 selects a shift position corresponding to one of the shift indices S1 to S7 and sets it as the starting shift position. Furthermore, if the changed driving mode is "auto steering mode," the starting setting unit 35 will select a shift position corresponding to one of the shift indices S1, S2, or S4 and set it as the starting shift position if the starting shift position set in the "normal mode" or "sub steering mode" immediately before the change was a shift position other than the selectable shift indices S1, S2, or S4 in "auto steering mode," i.e., a shift position corresponding to shift indices S3, S5, or S8.

[0041] Furthermore, the starting shift position is set such that, among the shift positions that can be set in "sub-steering mode" or "auto-steering mode", both the forward (F) position value and the reverse (R) position value are both less than or equal to the upper limit of the position value determined in accordance with "sub-steering mode" or "auto-steering mode". Additionally, the starting shift position is set such that, among the shift positions that can be set in "sub-steering mode" or "auto-steering mode", both the forward and reverse position values ​​are both less than or equal to the respective position values ​​of the starting shift position set in "normal mode". Specifically, as shown in Figure 6, if the starting shift position set in the "normal mode" immediately before the change was F4 / R2 of shift index S8, then the forward position value in "normal mode" is 4 and the reverse position value is 2. Therefore, when the changed driving mode is "sub-steering mode", the starting setting unit 35 sets the starting shift position to shift index S6 (F3 / R2) among the shift indices S1 to S7, where the upper limit of the forward position value is 4 or less, the upper limit of the reverse position value is 2 or less, and it is close to the starting shift position value set in "normal mode". Furthermore, as shown in Figure 6, when the driving mode is changed from "sub-steering mode" to "auto-steering mode", the shift index S3 (F2 / R2) among the shift indices S1, S2, and S4 is set as the starting shift position if the upper limit of the forward position value is 3 or less, the upper limit of the reverse position value is 2 or less, and it is close to the starting shift position value that was set in "sub-steering mode".

[0042] Furthermore, when the shift lever 28 is operated by the operator, the starting setting unit 35 forcibly sets one of several shift positions as the starting shift position based on the command signal from the shift lever 28. When the shift lever 28 is operated to raise the starting shift position (UP), the shift position is changed in the direction of increasing the index value in the order of shift indices S1 to S8. When the shift lever 28 is operated to lower the starting shift position (DOWN), the shift position is changed in the direction of decreasing the index value in the order of shift indices S8 to S1. At this time, if the driving mode is a second speed limit state in which a control function requiring speed limiting is active, such as "sub-steering mode" or "auto-steering mode", the starting setting unit 35 skips index values ​​that cannot be selected in "sub-steering mode" or "auto-steering mode" and performs the up or down operation.

[0043] Furthermore, if the operation to change the driving mode is performed while the work vehicle 10 is in motion, the starting setting unit 35 stores the changed driving mode in the state memory unit 33. When the forward / reverse selector lever 24 is in the "neutral (N)" position and the work vehicle 10 is in a stopped state, the starting setting unit 35 retrieves the changed driving mode from the state memory unit 33 and executes the process of resetting the starting shift position.

[0044] (Processing flow by the controller) Figure 7 is a flowchart showing the operation of the controller 30 according to this embodiment. As shown in Figure 7, the controller 30 repeatedly executes the following series of processes at predetermined time intervals.

[0045] First, the starting setting unit 35 of the controller 30 determines whether the forward / reverse selector lever 24 is in the "neutral (N)" position and whether the work vehicle is stopped (step S101). If, in step S101, it is determined that the forward / reverse selector lever 24 is not in the "neutral (N)" position or the work vehicle is not stopped (step S101: No), the starting setting unit 35 terminates processing. If, in step S101, it is determined that the forward / reverse selector lever 24 is in the "neutral (N)" position and the work vehicle is stopped (step S101: Yes), the starting setting unit 35 refers to the state memory unit 33 to obtain information on the driving mode of the currently selected work vehicle 10 in order to set the starting shift position (step S102).

[0046] Next, the starting setting unit 35 refers to the state memory unit 33 and determines whether the current driving mode of the work vehicle 10 has changed from the driving mode set immediately before (step S103). If it is determined in step S103 that the current driving mode of the work vehicle 10 has not changed from the driving mode set immediately before (step S103: No), the starting setting unit 35 maintains the starting shift position for the current driving mode (step S104). Furthermore, in step S103, if it is determined that the current driving mode of the work vehicle 10 has changed from the driving mode set immediately before (step S103: Yes), the starting setting unit 35 selects a starting shift position stored in the state memory unit 33 (step S105).

[0047] After step S104 or S105 is completed, the starting setting unit 35 determines whether or not the operator has operated the shift lever 28 (step S106). If it is determined that the operator has not operated the shift lever 28 (step S106: No), the starting setting unit 35 sets the starting shift position so that the starting shift position selected in step S104 or step S105 corresponds to the shift position selected at that time (step S107). For example, if the driving mode at that time is "sub-steering mode" or "auto-steering mode", the starting setting unit 35 sets the starting shift position so that the forward (F) position value and the reverse (R) position value of the shift positions that can be set in "sub-steering mode" or "auto-steering mode" are both less than or equal to the upper limit of the position value determined for "sub-steering mode" or "auto-steering mode". Furthermore, the starting shift position is set so that the forward and reverse position values ​​of the shift positions that can be set in the changed "sub-steering mode" or "auto-steering mode" are both less than or equal to the respective position values ​​of the starting shift position set in the previous "normal mode".

[0048] Furthermore, if it is determined that the shift lever 28 has been operated by the operator (step S106: Yes), the starting setting unit 35 resets the starting shift position from among the shift positions that can be set in the driving mode selected at that time, in accordance with the operation of the shift lever 28 (step S108). The starting setting unit 35 stores the starting shift position reset in step S108 in the state memory unit 33 as the new starting shift position for all driving modes (step S109).

[0049] In this way, the series of starting shift position settings in the controller 30 are completed.

[0050] Figure 8 shows another example of the starting shift position setting when the driving mode is changed in the controller 30 of the work vehicle 10 according to the embodiment. As shown in Figure 7, when the controller 30 repeatedly performs the process of setting the starting shift position, if the mode is changed from "normal mode" to "auto steering mode", in step S105, the index value of the shift index corresponding to the starting shift position stored in the state memory unit 33 (in the example in Figure 8, shift index S7: F3 / R3) is selected. In the subsequent step S107, in accordance with the changed driving mode, "auto steering mode", the shift index S4 F2 / R2 is set as the starting shift position. Subsequently, if the driving mode is changed from "auto steering mode" to "normal mode", the starting setting unit 35 selects the shift index S7 stored in the state memory unit 33, and the starting shift position is reset.

[0051] Figure 9 is a diagram showing yet another example of setting the starting shift position when the driving mode is changed in the controller 30 of the work vehicle 10 according to the embodiment. As shown in Figure 9, when the mode is changed from "normal mode" to "auto steering mode", in step S105, the index value of the shift index corresponding to the starting shift position stored in the state memory unit 33 (in the example of Figure 9, shift index S7: F3 / R3) is selected. Subsequently, in "auto steering mode", when the starting shift position is set to, for example, F1 / R2 of shift index S2 by the operator's operation of the shift lever 26, the starting shift position set in step S108 is stored in the state memory unit 33. Furthermore, after that, from "Auto Steering Mode" to "Normal Mode" and then "Normal Mode" Even when switching to "auto steering mode," in step S105, the starting shift position stored in the state memory unit 33 is selected, and in the subsequent step S107, the shift index S2 is set.

[0052] (Effects / Actions) According to this embodiment, an appropriate starting shift position can be selected according to the speed limit state of the work machine 100.

[0053] While embodiments of this invention have been described above with reference to the drawings, the specific configuration is not limited to the embodiments described above, and design changes and the like that do not depart from the spirit of this invention are also included.

[0054] For example, in the embodiment described above, the sub-steering mode and auto-steering mode were given as examples of driving modes requiring speed restrictions in contrast to the normal mode, but the invention is not limited to these, and other driving modes can be substituted as appropriate. Furthermore, while examples of selectable shift positions for each driving mode are shown, other shift positions can be selected as the starting shift position as appropriate.

[0055] Furthermore, some or all of the program executed by the computer in the above embodiment can be distributed via a computer-readable recording medium or communication line. [Explanation of Symbols]

[0056] 10...Work vehicle 18...Transmission 27...Shift lever (operating device) 30...Controller

Claims

1. It is a work vehicle, The transmission and A controller including a processor, Equipped with, The aforementioned controller, The system determines whether the work vehicle is in a normal mode, where no speed restriction is required, or a second speed restriction state, where a speed restriction is required. When a work vehicle is starting from a stationary position, and the work vehicle is in the second speed-restricted state, the speed of the work vehicle is restricted to a speed range that can be set as the starting speed range, which is the speed range applied at the time of starting. After the work vehicle starts, the system terminates the restriction of the work vehicle's speed to the speed range that can be set as the starting speed range, and controls the shift position of the transmission based on the driving conditions. Work vehicle.

2. The aforementioned controller, When the system changes from the normal mode to the second speed-restricted state, if the starting speed range set during the normal mode is outside the speed range that can be set during the second speed-restricted state, the set starting speed range is reset to one of the speed ranges that can be set during the second speed-restricted state. The work vehicle according to claim 1.

3. The aforementioned controller, During the second speed limit state, the speed range that can be set is reset to a speed range where both the position value indicating the speed range when moving forward and the position value indicating the speed range when moving backward are less than or equal to the upper limit value determined in accordance with the second speed limit state. The work vehicle according to claim 2.

4. The aforementioned controller, During the second speed limit state, the speed range that can be set is reset to a speed range where both the position value indicating the speed range when moving forward and the position value indicating the speed range when moving backward are less than or equal to the respective position values ​​of the starting speed range set during the normal mode. The work vehicle according to claim 2 or 3.

5. Equipped with an operating device, The controller sets one of a plurality of speed ranges as the starting speed range based on the command signal from the operating device. A work vehicle according to any one of claims 1 to 4.

6. The aforementioned controller, When the aforementioned starting speed range is set, the system stores an index value indicating the set starting speed range. If the aforementioned speed limit state changes, the starting speed range is set to the speed range indicated by the stored index value. A work vehicle according to any one of claims 1 to 5.

7. It is a work vehicle, The transmission and A controller including a processor, Equipped with, The aforementioned controller, The system determines whether it is in a normal mode, where no speed limit is required for the work vehicle, or in a second speed-limited state, where a speed limit is required. When the work vehicle is in the second speed restriction state, the speed range that can be set as the starting speed range, which is the speed range applied when starting, is restricted. The aforementioned controller, When the system changes from the normal mode to the second speed-restricted state, if the starting speed range set during the normal mode is outside the speed range that can be set during the second speed-restricted state, the set starting speed range is reset to one of the speed ranges that can be set during the second speed-restricted state. The aforementioned controller, During the second speed limit state, the speed range that can be set is reset to a speed range where both the position value indicating the speed range when moving forward and the position value indicating the speed range when moving backward are less than or equal to the respective position values ​​of the starting speed range set during the normal mode. Work vehicle.

8. It is a work vehicle, The transmission and A controller including a processor, Equipped with, The aforementioned controller, The system determines whether it is in a normal mode, where no speed limit is required for the work vehicle, or in a second speed-limited state, where a speed limit is required. When the speed limit state of the work vehicle is in the second speed limit state, the speed range that can be set as the starting speed range, which is the speed range applied when starting, is limited. The aforementioned controller, When the aforementioned starting speed range is set, the system stores an index value indicating the set starting speed range. If the aforementioned speed limit state changes, the starting speed range is set to the speed range indicated by the stored index value. Work vehicle.

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