Work vehicle

Abstract

To provide a work vehicle in which safety has been improved in road travelling, solving a problem with a conventional work vehicle performing work mode control in which a brake on a side where a steering device is operated is actuated and travelling mode control in which a brake is not actuated even when the steering device is operated that since control to shift the mode from the work mode to the travelling mode is not performed automatically when the work vehicle goes out of a farm field, it is dangerous if the work vehicle travels on the road in the work mode.SOLUTION: A work vehicle is quipped with a control device 25 having a work mode in which one of right and left brakes 4a on a side where a steering device is operated performs braking actuation and a travelling mode in which the brake 4a does not perform braking actuation even when the steering device is operated. When the mode is switched to the work mode by a mode changeover switch 20 for switching the mode either to the work mode or the travelling mode, it is determined that the work vehicle is on the road if there is an operation of a direction indicator operation unit 17 of a direction indicator, and control is performed so that the brake 4a does not perform braking actuation even when the steering device is operated.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a work vehicle such as an agricultural tractor. [Background technology]

[0002] There is a work vehicle equipped with a control device that performs a work mode control in which the brake on either the left or right side of the steering device is activated when the steering device is operated, and a driving mode control in which the brake is not activated even when the steering device is operated (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-096863 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, when in drive mode, the brakes are not applied even when the steering device is operated. However, there is no control to automatically switch to drive mode when leaving the field, so it is dangerous to drive on the road in work mode.

[0005] An object of the present invention is to provide a work vehicle that improves safety when traveling on roads. [Means for solving the problem]

[0006] The invention described in claim 1 is a work vehicle equipped with a control device 25 having a work mode that can be used for work in which either the left or right brake 4a on the side where the steering device 9 is operated applies a brake, and a drive mode that can be used for road driving in which the brake 4a does not apply a brake even when the steering device 9 is operated, and is provided with a mode change switch 20 that switches between work mode and drive mode, and when the mode change switch 20 is switched to work mode, if the direction indicator operating device 17 of the direction indicators 17L, 17R is operated, it determines that the vehicle is on the road and controls the brake 4a so that it does not apply a brake even when the steering device 9 is operated.

[0007] According to the invention described in claim 1, since the direction indicators 17L, 17R are not used in the field, if the direction indicator operating device 17 of the direction indicators 17L, 17R is operated, it is determined that the vehicle is on the road, and one side of the brake is not automatically applied when turning right or left, allowing safe driving.

[0008] The invention of claim 2 is the work vehicle of claim 1, in which the notification device M notifies the driver that the brakes 4a are controlled so as not to perform braking operation even when the steering device 9 is operated in work mode.

[0009] According to the invention described in claim 2, the notification device M notifies the driver that the brake 4a is controlled so that it will not operate even if the steering device 9 is operated in work mode, thereby prompting the driver to switch from work mode to traveling mode, thereby enabling safe traveling.

[0010] The invention of claim 3 is the work vehicle of claim 2, wherein when the operator switches from the work mode to the travel mode, the notification device M stops making a notification.

[0011] According to the invention of claim 3, by stopping the notification from the notification device M, it is possible to recognize that the mode has been switched to the running mode.

[0012] The invention described in claim 4 is a work vehicle described in claim 2 that is provided with a disconnection operating device 15 that disconnects the left and right brakes 4a and a lock lever 14 that regulates the operation of the disconnection operating device 15, and that uses an alarm device M to notify that the left and right brakes 4a have been disconnected.

[0013] According to the invention described in claim 4, if one brake is applied by mistake while driving on the road, the vehicle may make a sharp turn. Therefore, by using the alarm device M to notify the driver that the left and right brakes 4a have been released, the driver is prompted to connect the left and right brakes 4a, thereby improving safety.

[0014] The invention described in claim 5 is a work vehicle described in claim 1 that is provided with a front wheel double speed rotation function that increases the front wheel speed by operating the steering device 9, allowing for tight turns, and that is controlled so that the front wheel double speed rotation function does not operate when it is determined that the vehicle is on a road.

[0015] According to the invention described in claim 5, when the direction of travel is changed by operating the steering device 9 while driving on the road, if the front wheel double speed rotation function is activated, the vehicle may make an unexpected tight turn and fall over, so by controlling the function not to activate it, the vehicle can be driven safely. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a side view of a tractor according to an embodiment of the present invention to which a rotary tiller is attached. [Figure 2] 1 is a perspective view of a control section of a tractor according to an embodiment of the present invention. FIG. [Figure 3] 1 is a perspective view of a control section of a tractor according to an embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a plan view of a mode changeover switch unit of the tractor according to the embodiment of the present invention. [Figure 5] 1 is a diagram showing a transmission mechanism of a tractor according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] As one embodiment of the present invention, an agricultural tractor 1 equipped with a rotary tiller W, which is a type of work vehicle, will be described.

[0018] As shown in FIG. 1, the tractor 1 is an agricultural tractor that performs work in a field or the like while propelled by itself.

[0019] In the following, the forward / rearward direction refers to the direction of travel of the tractor 1 when traveling straight, with the front side of the traveling direction being defined as "front" and the rear side being defined as "rear." The traveling direction of the tractor 1 when traveling straight is the direction from the driver's seat 8 (described later) toward the steering wheel 9 serving as a steering device.

[0020] The left-right direction is a direction that is horizontally perpendicular to the front-rear direction. Hereinafter, left and right are defined as facing the "front." That is, when the operator of the tractor 1 (also referred to as the "operator") is seated in the operator's seat 8 and facing forward, the left-hand side is the "left" and the right-hand side is the "right."

[0021] The up-down direction is the vertical direction. The front-rear direction, left-right direction, and up-down direction are perpendicular to each other. Note that each direction is defined for the convenience of explanation, and the present invention is not limited by these directions. In the following, the tractor 1 may be referred to as the "machine body."

[0022] As shown in Figure 1, the tractor 1 includes a traveling body 2 and, at its rear, a work implement link mechanism L. The traveling body 2 includes a body frame 3 serving as a main frame, left and right drive front wheels 4 steered by a steering wheel 9, left and right drive rear wheels 5, a bonnet 6, an engine E, a control section 7 inside the cabin, and a transmission case 10.

[0023] The hood 6 is provided at the front of the vehicle body 2 so as to be able to be opened and closed freely. The front part of the hood 6 can be rotated (opened and closed) in the vertical direction around the rear part as the rotation center. When closed, the hood 6 covers the engine E mounted on the vehicle body frame 3.

[0024] The engine E is the driving source of the tractor 1 and is a heat engine such as a diesel engine or a gasoline engine.

[0025] The control section 7 is provided in a cabin provided on top of the traveling vehicle body 2, and includes a driver's seat 8, a steering wheel 9, and the like.

[0026] The driver's seat 8 is a seat for the driver. The steering wheel 9 is operated by the driver when steering the left and right front drive wheels 4.

[0027] The transmission case 10 houses a transmission (speed change mechanism) 39. The transmission case 10 appropriately reduces the speed of power (rotational power) transmitted from the engine E by the transmission 39 and transmits the power to the left and right front drive wheels 4 and the left and right rear drive wheels 5, which are drive wheels, and to the PTO shaft 40.

[0028] A rotary tiller W, which performs tilling work in the field, is connected to the rear of the traveling body 2 by a work machine link mechanism L, and a PTO shaft 40, which transmits power to drive the rotary tiller W, protrudes rearward from the transmission case 10.

[0029] The PTO shaft 40 transmits rotational power, appropriately reduced in speed by the transmission 39, to the rotary tiller W attached to at least the rear of the traveling body 2 via a drive shaft 41 with universal joints on both ends.

[0030] The rotary tiller W is a machine that performs tilling work in a farm field. The rotary tiller W tills the farmland (soil) by rotating the tiller tines 42 using power transmitted from a PTO shaft 40.

[0031] As shown in FIG. 2, the front operation panel FP at the front of the control unit 7 is provided with a monitor M, which is an informing device that displays various information in front of the steering wheel 9.

[0032] The front operation panel FP section at the front of the steering unit 7 is provided with various operation pedals such as an accelerator pedal 11, left and right brake pedals 12L, 12R that respectively apply braking force to the left and right brakes 4a of the left and right driven rear wheels 5, a clutch pedal 13, a disconnection pedal 15 as a disconnection operating device, and a parking pedal 16, as well as various operation levers such as a forward / reverse lever, an accelerator lever, a main shift lever, an auxiliary shift lever, a turn signal lever 17 as a direction indicator operating device, and a lock lever 14 that operates to connect the left and right brake pedals 12L, 12R.

[0033] The left brake pedal 12L activates the left brake 4a, and the right brake pedal 12R activates the right brake 4a.

[0034] The lock lever 14 is an operating tool that connects the left and right brake pedals 12L, 12R; when operated toward the bottom of the vertical groove of the inverted L-shaped guide groove 14a, the left and right brake pedals 12L, 12R are connected and the operation of the disconnection pedal 15 is restricted (locked); when operated toward the right end of the upper left-right horizontal groove, the restriction (lock) on the operation of the disconnection pedal 15 is released and the connection can be released; and when the disconnection pedal 15 is operated by pressing down on it, the left and right brake pedals 12L, 12R are disconnected.

[0035] When working in a field, the left and right brake pedals 12L, 12R are not connected, and when turning left, the left brake pedal 12L is depressed and the steering wheel 9 is turned to the left, allowing for a sharp left turn, and when turning right, the right brake pedal 12R is depressed and the steering wheel 9 is turned to the right, allowing for a sharp right turn, thereby improving work efficiency.

[0036] When traveling on the road, the left and right brake pedals 12L, 12R are connected to prevent sudden turns caused by only one brake being applied, thereby enabling safe traveling on the road.

[0037] When the left and right brake pedals 12L, 12R are not connected by the lock lever 14 (when a lock state detection sensor consisting of a microswitch that detects the lock lever 14 is provided at a position below the vertical groove of the inverted-L-shaped guide groove 14a, and the lock state detection sensor does not detect that the lock lever 14 is operated below the vertical groove of the inverted-L-shaped guide groove 14a, which is the operating position that connects the left and right brake pedals 12L, 12R, or when a decoupling possible state detection sensor consisting of a microswitch that detects the lock lever 14 is provided at the right end of the horizontal groove in the left-right direction above the inverted-L-shaped guide groove 14a, and a decoupling pedal detection sensor consisting of a microswitch that detects that the decoupling pedal 15 has been depressed is provided, and the decoupling possible state detection sensor detects the lock lever 14 and the decoupling pedal detection sensor detects that the decoupling pedal 15 has been depressed), the control device 25 displays "Left and right brakes uncoupled" on the monitor M to alert the driver.

[0038] Therefore, if the driver accidentally steps on only one of the left and right brake pedals 12L, 12R (one-sided brake) while driving on the road, the vehicle may make a sharp turn, so by issuing a warning, the driver is prompted to connect the left and right brakes 4a, thereby improving safety.

[0039] As shown in Figures 3 and 4, the right side operation panel SP on the right side of the operating unit 7 is provided with a mode changeover switch 20, which is a switch for switching between the work mode control and the driving mode control described below, and a preference changeover switch 21, which sequentially switches between preference settings.

[0040] The mode changeover switch 20 can be freely switched to a "travel" position, a "tillage" position, and a "precision" position.

[0041] When the mode selector switch 20 is set to the "travel" position, the vehicle enters travel mode control, and even if the steering wheel 9 is turned left or right by more than a predetermined amount and the left or right front wheels 4 are turned by more than a predetermined angle, the left and right brakes 4a are not activated, and the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right front wheels 4 relative to the left and right rear wheels 5, is disengaged, allowing the vehicle to travel safely on the road.

[0042] When the mode selector switch 20 is set to the "tilling" position, the machine enters work mode control, and when the steering wheel 9 is turned left or right by more than a predetermined amount and the left or right driving front wheels 4 are turned by more than a predetermined angle, the left or right brake 4a on the side that was turned is activated, and the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right driving front wheels 4 relative to the left and right driving rear wheels 5, is engaged, allowing for good sharp turns in the field and enabling work to be carried out with good workability.

[0043] When the mode changeover switch 20 is set to the "particular" position, the control enters work mode, and when the steering wheel 9 is turned left or right by more than a predetermined amount and the left or right driving front wheels 4 are turned by more than a predetermined angle, the left or right brake 4a on the side that was turned is activated, and the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right driving front wheels 4 relative to the left and right driving rear wheels 5, is engaged, allowing for good sharp turns in the field.Furthermore, when the steering wheel 9 is turned left or right by more than a predetermined amount, the system enters an automatic control state of the operator's choice, which combines other automatic controls such as auto-lift control that automatically raises the rotary tiller W, allowing work to be done with good efficiency in the work control state preferred by the operator.

[0044] Each time the preference changeover switch 21 is pressed, it sequentially switches between a plurality of automatic controls that combine work mode control with other automatic controls such as auto-lift control.

[0045] In addition, a control device (controller) 25 is provided inside the right side operation panel SP.

[0046] The control device 25 controls the engine E, the drive system and operating system of the traveling body 2, the rotary tiller W, and other parts, and is equipped with a recording unit that records various data.

[0047] Here, the control of the above-mentioned operation system and the drive system of the traveling vehicle body 2 will be explained based on FIG.

[0048] When the steering wheel 9 is turned left or right, the steering cylinder 27 is actuated to rotate the left and right knuckle arms 28, which in turn steers the left and right front drive wheels 4, and the vehicle is steered in the direction in which the steering wheel 9 is turned.

[0049] A front wheel turning angle sensor 29 is provided on the left knuckle arm 28, which detects the turning angle of the left and right front driving wheels 4 and inputs the result to the control device 25.

[0050] The control device 25 automatically controls the left and right front driving wheels 4 based on information on the turning angles of the left and right front driving wheels 4 from the front wheel turning angle sensor 29 as follows.

[0051] When the mode selector switch 20 is set to the "tillage" or "particular" position, the machine enters work mode control, and when the operator turns the steering wheel 9 to the right in order to turn the machine to the right in the field and the rotation angle of the left and right driving front wheels 4 reaches a predetermined angle or more, the right brake solenoid 30R is excited to operate the left and right brake valves 31, sending pressurized oil from the pump P to the right brake cylinder 32R to brake the right brake 4a, causing the machine to make a sharp right turn, and the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right driving front wheels 4 relative to the left and right driving rear wheels 5, is turned on, allowing the machine to make sharp turns in the field smoothly.

[0052] When the operator turns the steering wheel 9 left in the field to turn the machine left and the rotation angle of the left and right driving front wheels 4 reaches a predetermined angle or more, the left brake solenoid 30L is excited to operate the left and right brake valves 31, sending pressurized oil from the pump P to the left brake cylinder 32L to apply the braking force to the left brake 4a, causing the machine to make a sharp left turn, and the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right driving front wheels 4 relative to the left and right driving rear wheels 5, is engaged, thereby enabling smooth sharp turns in the field.

[0053] Furthermore, when driving out of the field onto the road with the mode selector switch 20 left in the "tillage" or "particular" position (including when the mode selector switch 20 has been forgotten to be set to the "driving" position), if the turn signal lever 17 is operated to activate either the left or right turn indicator (turn signal lamp) 17L, 17R when turning the machine right or left on the road, the operation information of the turn signal lever 17 is input to the control device 25, and the control device 25 ignores the rotation angle information of the left and right driving front wheels 4 from the front wheel turning angle sensor 29 that is greater than a predetermined angle, does not excite the left and right brake solenoids 30L, 30R, and does not apply the braking force to the left and right brakes 4a, preventing a situation where one brake applies the brakes on the road and causes a sharp turn to the left or right, and leaves the front wheel double speed clutch 35 of the front wheel double speed mechanism, which doubles the speed of the left and right driving front wheels 4 relative to the left and right driving rear wheels 5, in the disengaged state, allowing safe driving.

[0054] Therefore, since the turn signals 17L and 17R are not used in the field, if the turn signals 17L and 17R are operated (the turn signal lever 17 is operated), it is determined that the vehicle is on the road, and one side of the brake is not automatically applied when turning right or left, allowing the vehicle to travel safely.

[0055] In addition, when changing the direction of travel by operating the steering wheel 9 while driving on the road, if the front wheel double speed rotation function is activated, the vehicle may make an unexpected tight turn and fall over, so by controlling it not to be activated, the vehicle can be driven safely.

[0056] In addition, the monitor M displays "One brake - front wheel double speed off" to notify the driver that the left and right brakes 4a are not applied automatically by operating the steering wheel 9 in response to the operation of the above-mentioned turn signal lever 17, so that one brake does not apply braking, and that the front wheel double speed clutch 35 of the front wheel double speed mechanism is turned off so that the front wheel double speed mechanism does not operate.

[0057] Therefore, the monitor M displays "One brake, front wheel double speed off" to alert the operator, and the operator is prompted to switch the mode changeover switch 20 from the "tillage" position or "particular" position (working mode) to the "travel" position (traveling mode), thereby enabling safe travel.

[0058] When the operator switches the mode changeover switch 20 from the "tillage" or "particular" position (working mode) to the "travel" position (traveling mode), the display of "one brake / front wheel double speed off" on the monitor M disappears.

[0059] Therefore, by erasing the display of "One brake, front wheel double speed off" on the monitor M, it can be recognized that the mode changeover switch 20 has been switched to the "travel" position (travel mode).

[0060] In the above embodiment, the monitor M is used as an example of the notification device, but any notification means such as a notification lamp, notification sound, or voice notification may be used. [Explanation of symbols]

[0061] 4a Brake 9 Steering device (steering wheel) 14 Lock lever 15 Uncoupling operation device (uncoupling pedal) 17 Turn signal operating device (winker lever) 17L,17R Turn signal 20 Mode switch 25 Control device M Alarm device (monitor)

Claims

1. A work vehicle equipped with a control device (25) having a work mode that can be used for work in which one of the left and right brakes (4a) on the side where the steering device (9) is operated applies braking, and a travel mode that can be used for road travel in which the brakes (4a) do not apply braking even when the steering device (9) is operated, is provided with a mode changeover switch (20) that changes over to the work mode or the travel mode, and when the mode changeover switch (20) is switched over to the work mode, if the direction indicator operating device (17) of the direction indicators (17L, 17R) is operated, it is determined that the vehicle is on the road, and the brakes (4a) are controlled so that they do not apply braking even when the steering device (9) is operated.

2. 2. The work vehicle according to claim 1, wherein an annunciation device (M) notifies the driver that the brakes (4a) are controlled so as not to operate even when the steering device (9) is operated in the work mode.

3. 3. A work vehicle according to claim 2, wherein when the operator switches from the work mode to the travel mode, the notification device (M) stops issuing a notification.

4. 3. The work vehicle according to claim 2, further comprising a disconnection operating device (15) for disconnecting the left and right brakes (4a) and a lock lever (14) for restricting the operation of the disconnection operating device (15), and an alarm device (M) for notifying that the left and right brakes (4a) have been disconnected.

5. A work vehicle as described in claim 1, characterized in that it is provided with a front wheel double speed rotation function that allows the front wheels to increase in speed by operating the steering device (9) to make tight turns, and is controlled so that the front wheel double speed rotation function does not operate when it is determined that the vehicle is on a road.

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