Title of Invention: Work Vehicle
Technical field
[0001]
　The present invention relates to work vehicles such as tractors.
Background technology
[0002]
　2. Description of the Related Art Conventionally, a technique disclosed in Patent Document 1 is known as a technique for controlling the plowing depth of a tractor. In the tractor of Patent Document 1, a rotary tillage device connected to the machine body so that it can be driven up and down, a rear cover provided at the rear of the rotary tillage device that can swing up and down following ground contact, and a vertical swing amount of the rear cover. a cover sensor for detecting a target tillage depth setting means for setting the target tillage depth of the rotary tillage device; and automatic lift control means for operating the lift drive mechanism.
prior art documents
patent literature
[0003]
Patent Document 1: Japanese Patent Publication "JP 2000-184804"
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0004]
　In the tractor as shown in Patent Document 1, plowing can be performed so that the position of the rotary plowing device becomes the target plowing depth. In a field, when tillage by the rotary tillage device is finished and the tractor turns, the rotary tillage device can be raised and then turned, and after turning, can be tilled again by the rotary tillage device. On the other hand, it is actually difficult to raise or lower the rotary tiller according to the work situation when tilling with the rotary tiller. Further, when plowing is resumed after the rotary tillage device is raised and lowered while tillage is being carried out, the tillage depth must be set again, which may reduce working efficiency. In addition, when the work device other than the rotary tillage device is moved up and down during work, it is necessary to reset the settings for the work.
[0005]
　In addition, in the tractor disclosed in Patent Document 1, there are many restrictions on lifting and lowering a working device other than a rotary tillage device during work, and it is sometimes difficult to raise and lower the working device according to the work. rice field.
　Therefore, in view of the above-mentioned problems, the present invention makes it possible to easily raise and lower the working device while the working device is working according to the working situation, and to easily return to the work before lifting and restarting the work. The purpose is to provide a work vehicle that can Further, it is desirable to provide a working vehicle that can easily raise and lower the working device according to the working situation while the working device is working, and return the working device to an appropriate position after the lifting and lowering to continue the work. aim.
Means to solve problems
[0006]
　The technical means of the present invention for solving this technical problem are characterized by the following points.
　The work vehicle includes a vehicle body, a lifting device provided on the vehicle body, a first setting member for setting a reference position in a height direction of the working device connected to the lifting device, and a lifting device for operating the lifting device. an elevation operation member; a first elevation control unit that performs reference elevation control for raising and lowering the elevation device so that the work device is at the reference position; and the reference elevation when the elevation operation member is operated during the work. a second elevation control section that stops control and raises and lowers the elevation device according to the operation of the elevation operation member, wherein the first elevation control section controls the elevation operation member after stopping the reference elevation control; When the operation of is released, control is performed to return the lifting device to the position corresponding to the reference position.
[0007]
　The first elevation control unit resumes the reference elevation control after performing control to return the elevation device to a position corresponding to the reference position.
　The second elevation control section raises and lowers the elevation device within a set range between an upper limit value and a lower limit value of heights that can be set by the first setting member when the elevation operation member is operated.
　The work vehicle includes a second setting member capable of setting an upper limit value of the height of the lifting device, and the second lifting control unit operates the lifting device at a height equal to or lower than the upper limit value set by the second setting member. ascend and descend.
[0008]
　The second elevating control section elevates the elevating device during operation of the elevating operation member.
　The first setting member can set the plowing depth of the working device as a reference position of the working device, and the first elevation control unit lifts and lowers the lifting device so that the plowing depth is constant.
　The work vehicle includes a vehicle body, a lifting device provided on the vehicle body, a first lifting operation tool for operating the lifting device to move up and down, and lifting and lowering the lifting device while the first lifting operation tool is operated, an elevation control device that moves the elevation device from the position where the operation is canceled to another position when the operation is cancelled.
[0009]
　The work vehicle includes a mode switching member for switching between a first mode and a second mode, and when the first mode is selected, the lifting control device switches the lifting device while the first lifting operation tool is being operated. and when the operation is canceled, the lifting and lowering of the lifting device is stopped, and in the case of the second mode, the lifting and lowering device is lifted and the operation is performed while the first lifting operation tool is being operated. is released, the lifting device is moved to a predetermined position.
[0010]
　The first elevating operation tool has a first elevating operation section for operating the elevation device and a first descent operating section for operating the descent operation, and the elevating control device operates the first elevation operation section. During operation, the lifting device is lifted, and the lifting device is lowered during the operation of the first lowering operation section.
　The work vehicle includes: a second lifting operation tool having a second lifting operation part for operating the lifting device and a second lowering operation part for operating the lifting device; and upper and lower limits of the height of the lifting device. and a height setting tool capable of setting the elevation control device, when the second elevation operation unit is operated, raises the elevation device to the upper limit position, and the second lowering operation unit When operated, the lifting device is lowered to the lower limit position.
[0011]
　The first lifting operation tool and the second lowering operation tool are arranged side by side.
　The work vehicle includes a first setting member for setting a reference position in the height direction of the working device connected to the lifting device, and the lifting control device operates the first lifting operation tool in the second mode. is released, the predetermined position is set to the reference position, and reference elevation control is performed to raise and lower the elevation device so that the elevation device is positioned at the reference position.
Effect of the invention
[0012]
　According to the present invention, the work device can be easily moved up and down during work by the work device according to the work situation, and the work can be resumed by simply returning to the work before the lifting and lowering. Further, according to the present invention, the work device can be easily moved up and down during work by the work device according to the work situation, and the work device can be returned to the proper position after the up and down operation to continue the work.
Brief description of the drawing
[0013]
1 is a control block diagram for raising and lowering a tractor; FIG.
2 is a perspective view of a lifting device; FIG.
3 is a plan view of a driver's seat and an armrest; FIG.
4 is a left side view of the driver's seat and the armrest; FIG.
5 is a perspective view of an armrest; FIG.
6A is an explanatory diagram for explaining a reference position P1; FIG.
6B is an explanatory diagram for explaining an upper limit height H1; FIG.
6C] A diagram showing a relationship between a reference position P1 and a detection position P2. [FIG.
7A is a diagram showing a state from stop to return of reference lifting control. FIG.
[Fig. 7B] Fig. 7B is a diagram showing how the working device is lowered and then returned to a predetermined position.
8 is a diagram showing the relationship between the operation of the first lifting operation tool and the control signal; FIG.
9 is an overall view of the tractor; FIG.
MODE FOR CARRYING OUT THE INVENTION
[0014]
　BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　FIG. 9 shows a tractor 1 as an example of a work vehicle. Although the tractor 1 will be described as an example, the work vehicle is not limited to a tractor, but may be an agricultural machine such as a rice transplanter.
　As shown in FIG. 9 , the tractor 1 includes a traveling vehicle body (vehicle body) 3 having a traveling device 7 , a prime mover 4 , a transmission 5 and a steering handle 6 . The traveling device 7 is a device having front wheels 7F and rear wheels 7R. The front wheels 7F may be of a tire type or a crawler type. Also, the rear wheel 7R may be of a tire type or a crawler type. The prime mover 4 is an internal combustion engine such as a gasoline engine or a diesel engine, an electric motor, or the like. In this embodiment, prime mover 4 is a diesel engine.
[0015]
　The transmission device 5 can switch the driving force of the traveling device 7 by changing speed, and can switch the traveling device 7 between forward and reverse. A cabin 9 is provided in the traveling vehicle body 3, and a driver's seat 10 is provided in the cabin 9. - 特許庁
　A lifting device 8 is provided at the rear portion of the traveling vehicle body 3 . The working device 2 can be attached to and detached from the lifting device 8 . Further, the lifting device 8 is capable of lifting and lowering the work device 2 mounted thereon. The work device 2 includes a tillage device for tilling, a fertilizer spraying device for spraying fertilizer, an agricultural chemical spraying device for spraying agricultural chemicals, a harvesting device for harvesting, a harvesting device for cutting pasture grass, a spreading device for spreading pasture grass, etc. Examples include a grass collecting device for collecting pasture grass, a forming device for forming pasture grass, and the like.
[0016]
　As shown in FIG. 2, the lifting device 8 has a lift arm 8a, a lower link 8b, a top link 8c, a lift rod 8d and a lift cylinder 8e. A front end portion of the lift arm 8a is supported by a rear upper portion of a case (transmission case) that houses the transmission 5 so as to be capable of swinging upward or downward. The lift arm 8a swings (moves up and down) by being driven by a lift cylinder 8e. The lift cylinder 8e is composed of a hydraulic cylinder. As shown in FIG. 1, the lift cylinder 8e is connected via a control valve 36 to a hydraulic pump. A control valve (hydraulic control valve) 36 is an electromagnetic valve or the like, and expands and contracts the lift cylinder 8e. For example, the control valve 36 is a three-position switching valve that can be switched between a first position, a second position, and a neutral position. In some cases, the lift cylinder 8e can be retracted (lowered).
[0017]
　A front end portion of the lower link 8b is supported by a lower rear portion of the transmission 5 so as to be capable of swinging upward or downward. A front end portion of the top link 8c is supported by the rear portion of the transmission 5 above the lower link 8b so as to be able to swing upward or downward. The lift rod 8d connects the lift arm 8a and the lower link 8b. The working device 2 is connected to the rear portion of the lower link 8b and the rear portion of the top link 8c. When the lift cylinder 8e is driven (extended and retracted), the lift arm 8a moves up and down, and the lower link 8b connected to the lift arm 8a via the lift rod 8d moves up and down. As a result, the work device 2 swings upward or downward (elevates) with the front portion of the lower link 8b as a fulcrum.
[0018]
　As shown in FIG. 7A, a tillage device 2A, which is one of the work devices 2 connected to the lifting device 8, will be described. The tillage device 2A includes a gear case 101 to which the power of the PTO shaft 16 is transmitted, a drive case 102 to which the power of the gear case 101 is transmitted and which extends downward, a rotary shaft 103 rotatably supported by the drive case 102, It has a tillage claw 104 attached to a rotating shaft 103 . The gear case 101 and the drive case 102 are provided with a transmission mechanism for transmitting power, and the transmission mechanism transmits the power of the PTO shaft 16 to rotate the rotating shaft 103 so that the plowing tines 104 can plow. It is possible. A mast 107 is provided on the top of the gear case 101 . The rear end of the top link 8c is connected to a connecting body (quick coupler) 108, the rear end of the lower link 8b is connected to a connecting body 108, and the upper part of the connecting body 108 is hooked to the mast 107, thereby enabling tillage. The device 2A is connected to the lifting device 8 via a connecting body 108. As shown in FIG. The tillage device 2A has a fixed cover 110 fixed to a support frame 109 that supports the gear case 101, and a swingable cover 111 supported by the fixed cover 110 so as to be swingable (swingable in the vertical direction). is doing. The rear end of the rocking cover 111 is placed on the field (ground), and the rocking cover 111 rocks when the height position of the cultivator 2A changes with respect to the ground. The swing cover 111 is provided with a detection device (not shown) for detecting swing, and detects the swing amount of the swing cover 111, that is, the position (detection position) P2 of the tiller 2A in the height direction. It is possible to The detection device may be, for example, a sensor that detects the amount of rocking of the rocking cover 111. Alternatively, one end of a wire is connected to the rocking cover 111 and the other end of the wire is extended toward the tractor 1 to detect the amount of the wire. The amount of swing may be detected by the movement of , but is not limited. The detection information (detection value) detected by the detection device is input to the elevation control device 40, which will be described later.
[0019]
　As shown in FIGS. 3 to 5, an armrest 120 is provided on the side of the driver's seat 10, for example.
　The armrest 120 includes a left side portion 120A arranged on the driver's seat 10 side, a right side portion 120B arranged in a direction away from the driver's seat 10 side, and a rear portion between the left side portion 120A and the right side portion 120B. a rear surface portion 120C disposed on the side; a front surface portion 120D disposed on the front side between the left side portion 120A and the right side portion 120B; and an upper surface portion 120E that connects the upper portion of the portion 120D. Various operating members are provided on the armrest 120 .
[0020]
　The armrest 120 is provided with a shift lever 20 for shifting the transmission 5, a setting button 21 for setting the engine speed, a setting button 22 for setting the vehicle speed, and a mode switching member 23 for switching modes. . The mode switching member 23 is a push-type switch that can be switched ON/OFF.
　The tractor 1 includes a lifting operation member 51 that operates the lifting device 8 to move up and down. The lifting operation member 51 includes a first lifting operation tool 51A, a second lifting operation tool 51B, and a third lifting operation tool 51C. The first lifting operation tool 51A, the second lifting operation tool 51B, and the third lifting operation tool 51C are provided on the armrest 120. As shown in FIG. For example, the first lifting operation tool 51A and the second lifting operation tool 51B are provided on the left side portion 120A, and the third lifting operation tool 51C is provided on the upper surface portion 120E. The first lifting operation tool 51A and the second lifting operation tool 51B are arranged side by side. A mode switching member 23 is provided above the first lifting operation tool 51A and the second lifting operation tool 51B. 51 A of 1st raising/lowering operation tools and the 2nd raising/lowering operation tool 51B are arrange|positioned in the shape of inclination so that it may shift to the rear side as it goes from the upper part to the lower part. 51 A of 1st raising/lowering operation tools and the 2nd raising/lowering operation tool 51B are arrange|positioned shifted|deviated in the up-down direction. That is, the upper end of the second lifting operation tool 51B is arranged at a position lower than the upper end of the first lifting operation tool 51A. The arrangement of the first lifting operation tool 51A, the second lifting operation tool 51B, and the third lifting operation tool 51C is an example and is not limited.
[0021]
　The first lifting operation tool 51A has a first lifting operation portion 61U for operating the lifting device 8 to rise, and a first lowering operation portion 61D for operating the lifting device 8 to descend. Each of the first raising operation part 61U and the first lowering operation part 61D is, for example, a push switch. The first lift operation unit 61U issues a lift command when pressed, and cancels the lift command when not pressed. The first lowering operation unit 61D issues a lowering command when pressed, and cancels the lowering command when not pressed.
[0022]
　The second lifting operation tool 51B has a second lifting operation part 62U for operating the lifting device 8 to move up and a second lowering operation part 62D for operating the lifting device 8 to move down. Each of the second raising operation part 62U and the second lowering operation part 62D is, for example, a seesaw switch. The second raising operation part 62U gives a command to rise when pushed and rocked to one side, and the second lowering operation part 62D gives a command to go down when pressed and rocked to the other side.
[0023]
　The third lifting operation tool 51C is, for example, a rotary operation tool that rotates in one direction or the other. When the knob 63 is moved to the other side (rear side), a lowering command is issued in accordance with the amount of operation. That is, the third lifting operation tool 51C can adjust the lifting of the lifting device 8 according to the amount of operation. It should be noted that the elevation range when the third elevation operation tool 51C is operated (the elevation range when operated from the maximum to the minimum) is larger for the third elevation operation tool 51C than the elevation range for the first elevation operation tool 51A. May be set.
[0024]
　As shown in FIG. 1, the tractor 1 includes a first setting member 71 and a second setting member 72. As shown in FIG. The first setting member 71 is a member for setting a reference position P1 in the height direction of the working device 2 connected to the lifting device 8 . As shown in FIGS. 3 and 5, the first setting member 71 is a rotary switch and has a knob 71A rotatably supported on a vertical axis. As shown in FIG. 6A, when the knob portion 71A is rotated to one side (left side), the reference position P1 is set at a low position, and when the knob portion 71A is rotated to the other side (right side), the reference position P1 is set to , is set high. The first setting member 71 can be set to the minimum reference position P1min when it is rotated to one side to the maximum, and can be set to the maximum reference position P1max when it is rotated to the other side to the maximum. can be done. In this embodiment, the first setting member 71 is a tillage depth setting dial for setting the depth of tillage. The first setting member 71 is not particularly limited as long as it is a member that sets the reference position P1 of the working device 2 in the height direction.
[0025]
　As shown in FIG. 1, the second setting member 72 is a member capable of setting an upper limit value (height upper limit value) H1 of the height of the lifting device 8 . Like the first setting member 71, the second setting member 72 also has a knob portion 72A rotatably supported on the vertical axis. As shown in FIG. 6B, when the knob portion 72A is rotated to one side (left side), the height upper limit value H1 of the lift rod 8d when the lift cylinder 8e of the lifting device 8 is extended (the angle θ of the lift rod 8d ) increases, and when the knob 72A is rotated to the other side (right side), the height upper limit H1 of the lift rod 8d (the upper limit of the angle θ of the lift rod 8d) decreases. That is, the second setting member 72 sets the upper limit value H1 of the height of the lifting device 8 by setting the upper limit value of the angle θ of the lift rod 8d.
[0026]
　As shown in FIG. 1 , the tractor 1 includes a lift control device 40 that controls the lift device 8 . A control valve (hydraulic control valve) 36 is connected to the elevation control device 40 . When the lift control device 40 outputs a control signal that excites the extension-side solenoid of the hydraulic control valve 36, the hydraulic control valve 36 switches to the first position, and the lift cylinder 8e extends (rises). When the lift control device 40 outputs a control signal that excites the retraction-side solenoid of the hydraulic control valve 36, the hydraulic control valve 36 is switched to the second position, and the lift cylinder 8e is retracted (lowered). When the solenoid of the hydraulic control valve 36 is deenergized, the lift control device 40 can stop the lift cylinder 8e at an arbitrary position.
[0027]
　The elevation control device 40 includes a first elevation control section 40A and a second elevation control section 40B. The first elevation control unit 40A performs reference elevation control for raising and lowering the elevation device 8 so that the working device 2 is at the reference position P1. When the elevation operation member 51 is operated during work, the second elevation control section 40B stops the reference elevation control and raises and lowers the elevation device 8 according to the operation of the elevation operation member 51 .
[0028]
　Hereinafter, the reference elevation control and the like will be described by taking the tillage by the tillage device 2A as an example.
　As shown in FIG. 7A, when tilling is performed, the reference position P1 set by the first setting member 71 is set as the position of the rear end of the swing cover 111. As shown in FIG. That is, the plowing depth H2 is set by setting the position of the rear end of the rocking cover 111 to the reference position P1.
　As shown in FIG. 6C, the first elevation control unit 40A starts the reference elevation control while the cultivator 2A is being driven. In the reference elevation control, when the detection position P2 of the swing cover 111 is higher than the reference position P1, the first elevation control section 40A outputs a control signal (lowering control signal) to the hydraulic control valve 36 to detect Control is performed so that the position P2 coincides with the reference position P1. On the other hand, in the reference elevation control, when the detected position P2 of the swing cover 111 is lower than the reference position P1, the first elevation control section 40A outputs a control signal for elevation (raise control signal) to the hydraulic control valve 36. , the detection position P2 is controlled to coincide with the reference position P1. That is, the first elevation control section 40A controls the elevation of the elevation device 8 in the reference elevation control so that the deviation ΔP between the reference position P1 and the detection position P2 becomes zero.
[0029]
　The second elevation control section 40B stops the reference elevation control performed by the first elevation control section 40A when the first raising operation section 61U is operated under the condition that the reference elevation control is being performed. Then, the second elevation control unit 40B outputs an elevation control signal to the hydraulic control valve 36 while the first elevation operation unit 61U is operated (pressed). to raise the rear end of the lift rod 8d of the lifting device 8 (operation corresponding control).
[0030]
　When the operation (pressing is not performed) of the first raising operation portion 61U is released, the first elevation control portion 40A changes the position of the rear portion (rear end) of the swing cover 111 connected to the elevation device 8 to Control to return to the position corresponding to the reference position P1 is performed (return control). That is, when the operation of the first lifting operation part 61U is released, the first lifting control part 40A outputs a lowering control signal to the hydraulic control valve 36 to lower the rear end of the lift rod 8d of the lifting device 8. Let
[0031]
　Further, after the first lifting control unit 40A performs control to return the lifting device 8 to the position corresponding to the reference position P1, the difference between the detection position P2 of the swing cover 111 and the reference position P1 becomes equal to or less than the threshold. At this point, the reference lift control is resumed.
　FIG. 7A is a diagram showing how the reference elevation control is stopped and restored.
　As shown in FIG. 7A, under the condition that the reference elevation control is performed by the first elevation control section 40A, the tillage depth is controlled to be H2. Under such circumstances, when the first elevation operation unit 61U is operated (OFF→ON) as shown at time P10 in FIG. 7A, the reference elevation control by the first elevation control unit 40A is stopped (OFF). , the operation response control by the second elevation control unit 40B is started (OFF→ON). When the lifting operation member 51 is the first lifting operation tool 51A, the second lifting control part 40B controls the lifting operation during the period T1 during which the first lifting operation part 61U of the first lifting operation tool 51A is being operated. Continue to raise the device 8 (tillage device 2A). Note that the second elevation control unit 40B keeps the height of the elevation device 8 (cultivation device 2A) from the height upper limit value set in the second setting member 72 even when the first elevation operation unit 61U is being operated. When reaching H1, the lift device 8 is stopped. That is, the second elevation control section 40B raises and lowers the elevation device 8 below the upper limit value H1 set by the second setting member 72 .
[0032]
　As shown at time P11 in FIG. 7A, when the operation of the first elevation operation unit 61U is canceled (OFF), the operation response control by the second elevation control unit 40B is stopped (OFF), and the first elevation control unit After the return control by 40A is performed for a predetermined time (OFF→ON), at time point P12, the reference lift control by the first lift control unit 40A is resumed (OFF→ON).
　In the above-described embodiment, the reference elevation control and return control performed by the first elevation control unit 40A are described separately. In this case, return control may be included in the reference elevation control.
[0033]
　According to the above, the first elevation control unit 40A of the elevation control device 40 operates the first elevation operation tool 51A under the condition that the reference elevation control is performed to match the height of the working device 2 to the reference position P1. is released, the lifting device 8 can be controlled to return to the position corresponding to the reference position P1.
　In the above-described embodiment, the tillage work and the operation of the first lifting operation unit 61U are described as examples, but the control of the first elevation control unit 40A and the second elevation control unit 40B is not limited to the above-described embodiment.
[0034]
　For example, in the work device 2 that does not perform tillage work, the reference position P1 is set by the first setting member 71, and the reference elevation control is performed by the first elevation control unit 40A so that the work device 2 is at the reference position P1 during work. conduct. On the other hand, in the reference elevation control, for example, when the first lowering operation section 61D is operated, the reference elevation control is stopped and the elevation device 8 is lowered by the operation corresponding control of the second elevation control section 40B. When the operation of the first lowering operation section 61D is canceled, the operation corresponding control of the second elevation control section 40B is stopped, and the reference elevation control of the first elevation control section 40A is resumed.
[0035]
　The elevation control device 40 can be switched between the first mode and the second mode by the mode switching member 23 . When the mode switching member 23 is OFF, the elevation control device 40 is set to the first mode. Further, when the mode switching member 23 is ON, the elevation control device 40 is set to the second mode. The operation when the first lifting operation tool 51A is operated differs depending on whether the lifting control device 40 is in the first mode or the second mode.
[0036]
　As shown in FIG. 8, in the first mode, the elevation control device 40 operates while the first elevation operation tool 51A is operated (during operation), that is, when the first elevation operation unit 61U is pressed. During this time, the lifting control signal is continuously output to the hydraulic control valve 36 to raise the lifting device 8 . As shown at time P20 in FIG. 8, when the operation of the first lifting operation tool 51A is canceled (the first lifting operation unit 61U is no longer pushed), the lifting control device 40 is hydraulically operated. The lift control signal to the control valve 36 is stopped to stop the lift device 8 from lifting.
[0037]
　As shown at time P21 in FIG. 8, when the lifting device 8 reaches the height upper limit H1 while the lifting device 8 is being lifted, the lifting control device 40 outputs the control signal L1. Thus, the output of the lift control signal to the hydraulic control valve 36 is stopped even when the first lift operation portion 61U is pressed.
　In the first mode, the elevation control device 40 maintains the hydraulic pressure while the first elevation operation tool 51A is being operated (during operation), that is, while the first lowering operation section 61D is being pressed. A lowering control signal is continuously output to the control valve 36 to lower the lifting device 8 .
[0038]
　On the other hand, in the second mode, the elevation control device 40 raises and lowers the elevation device 8 while the first elevation operation tool 51A is being operated, as described above. is released, the lifting device 8 is moved to a predetermined position. For example, as shown in FIG. 7A, the elevation control device 40 performs reference elevation control for raising and lowering the work device 2 with the reference position P1 as a predetermined position.
[0039]
　Alternatively, when in the second mode, the elevation control device 40 continues to send the lowering control signal to the hydraulic control valve 36 while the first lowering operation section 61D is being pressed, as shown at time P30 in FIG. 7B. , to lower the lifting device 8, and stop the lowering control signal to the hydraulic control valve 36 when the first lowering operation part 61D is no longer pressed as shown at time P31, and then output the raising control signal. Output to the hydraulic control valve 36 . In addition, in the second mode, the elevation control device 40 outputs the elevation control signal when the elevation device 8 returns to the state (predetermined position) before it descends at time P30, as shown at time P32 in FIG. 7B. Stop.
[0040]
　In the above-described embodiment, the second setting member 72 is used to set the upper limit height H1, but as shown in FIG. may have
　Like the second setting member 72, the third setting member 73 also has a knob portion 73A rotatably supported on the vertical axis. When the lower limit value H3 of the height of the lift rod 8d (the lower limit value of the angle θ of the lift rod 8d) when the lift cylinder 8e of the lifting device 8 is contracted increases, and the knob portion 72A rotates to the other side (right side). , the lower limit value H3 of the height of the lift rod 8d (the lower limit value of the angle θ of the lift rod 8d) decreases. In this case, the second setting member 72 and the third setting member 73 allow the tractor 1 to set both the upper limit height H1 and the lower limit height H3 of the lifting device 8. you will have the equipment. In this case, when the second lifting operation part 62U of the second lifting operation tool 51B is operated, the lifting control device 40 controls the lifting device 8 to rise to the height upper limit value H1 regardless of the first mode or the second mode. I do. When the second lowering operation section 62D is operated, the elevation control device 40 performs control to lower the elevation device 8 to the height lower limit value H3 regardless of the first mode or the second mode.
[0041]
　The work vehicle 1 includes a vehicle body 3, a lifting device 8 provided on the vehicle body 3, a first setting member 71 for setting a reference position P1 in the height direction of the working device 2 connected to the lifting device 8, and a lifting device. 8, a first elevation control unit 40A that performs reference elevation control for raising and lowering the elevation device 8 so that the working device 2 is at the reference position P1, and the elevation operation member 51 during work. and a second elevation control unit 40B that stops the reference elevation control and raises and lowers the elevation device 8 according to the operation of the elevation operation member 51 when the first elevation control unit 40A stops the reference elevation control. After that, when the operation of the lifting operation member 51 is released, control is performed to return the lifting device 8 to the position corresponding to the reference position P1. According to this, in a situation in which work is being performed while performing the reference elevation control that raises and lowers the elevation device 8 so that the work device 2 is at the reference position P1, it is possible to operate the elevation operation member 51 during the work. As a result, the work device can be easily moved up and down, and when the operation of the up-and-down operation member 51 is released, the work before the up-and-down operation can be easily resumed.
[0042]
　After controlling the lifting device 8 to return to the position corresponding to the reference position P1, the first lifting control section 40A resumes the reference lifting control. According to this, when the lifting device 8 is lifted by operating the lifting operation member 51 during work, the state before the lifting operation member 51 is operated (the state before lifting) is restored, and the work by the reference lifting control can be performed. can continue.
　When the elevation operation member 51 is operated, the second elevation control unit 40B raises and lowers the elevation device 8 within a setting range between the upper limit value and the lower limit value of the height that can be set by the first setting member 71 . According to this, since the lifting operation member 51 can be moved up and down within the setting range between the upper limit value and the lower limit value of the reference position P1, the work can be smoothly shifted to the reference lifting control even after the lifting operation has been performed. The work device 2 can be temporarily moved up and down without interfering with the work performed by the reference up-and-down control.
[0043]
　The work vehicle 1 is provided with a second setting member 72 capable of setting the upper limit of the height of the lifting device 8, and the second lifting control unit 40B controls the lifting device at the upper limit set by the second setting member 72 or less. 8 up and down. According to this, for example, even within the setting range between the upper limit value and the lower limit value of the reference position P1, it is possible to prevent the work device 2 from being raised beyond the upper limit value of the height of the lifting device 8. can.
　The second elevating control section 40B elevates the elevating device 8 while the elevating operation member 51 is being operated. According to this, since the lifting operation can be performed only while the lifting operation member 51 is being operated (during operation), the height of the work device 2 can be set as desired by the driver (operator). can. In other words, fine adjustment of the height of the working device 2 can be easily performed.
[0044]
　The first setting member 71 can set the plowing depth of the working device 2 as the reference position P1 of the working device 2, and the first lifting control section 40A lifts and lowers the lifting device 8 so that the plowing depth is constant. According to this, the work device 2 can be raised and lowered by the elevation operation member 51 during plowing, and workability can be further improved.
　The work vehicle 1 includes a vehicle body 3, a lifting device 8 provided on the vehicle body 3, a first lifting operation tool 51A for operating the lifting and lowering of the lifting device 8, and an operation of the lifting device 8 during operation of the first lifting operation tool 51A. and an elevation control device 40 that raises and lowers and moves the elevation device 8 from the position where the operation is canceled to another position when the operation is canceled. According to this, the working device 2 can be easily moved up and down only while the first lifting operation tool 51A is being operated (during operation) during work by the working device 2, and the first lifting operation tool 51A can be lifted. When the operation of is released, the work device can be returned to the proper position after the lifting and the work can be continued.
[0045]
　The work vehicle 1 includes a mode switching member 23 for switching between the first mode and the second mode, and the elevation control device 40 switches the elevation device during the operation of the first elevation operation tool 51A when in the first mode. 8 is lifted and the operation is canceled, the lifting of the lifting device 8 is stopped, and in the case of the second mode, the lifting device 8 is lifted and the operation is canceled while the first lifting operation tool 51A is being operated. Then, the lifting device 8 is moved to a predetermined position. According to this, by switching between the first mode and the second mode, only while the first lifting operation tool 51A is being operated (during operation), the lifting device 8 (working device 2) is lifted and lowered to the intended position. After the lifting device 8 (working device 2) is stopped or the first lifting operation tool 51A is temporarily moved up and down, the height of the working device 2 can be returned to a predetermined position (predetermined height). can work according to
[0046]
　The first elevation operation tool 51A has a first elevation operation section 61U for operating the elevation of the elevation device 8 and a first descent operation section 61D for operating the descent. The lifting device 8 is lifted during the operation of , and the lifting device 8 is lowered during the operation of the first lowering operation section 61D. According to this, the raising and lowering of the lifting device 8 (working device 2) can be performed separately, and the height of the working device 2 can be finely adjusted.
[0047]
　A second lifting operation tool 51B having a second lifting operation part 62U for operating the lifting of the lifting device 8 and a second lowering operation part 62D for operating the lowering of the lifting device 8, and upper and lower limits of the height of the lifting device 8 and a height setting tool that can be set, and the elevation control device 40 raises the elevation device 8 to a position corresponding to the upper limit value when the second raising operation unit 62U is operated, and the second lowering operation unit When 62D is operated, the lifting device 8 is lowered to the position corresponding to the lower limit. According to this, in a situation where the height can be adjusted by the first lifting operation tool 51A, the lifting device 8 (working device 2) can be raised to the upper limit height at once, or the lifting device 8 (working device 2) 2) can be lowered to the lower limit at once.
[0048]
　The first lifting operation tool 51A and the second lifting operation tool 51B are arranged side by side. According to this, it is possible to quickly move up and down as required while properly using the lifting mode of the lifting device 8 (working device 2).
　The work vehicle 1 includes a first setting member 71 for setting a reference position P1 in the height direction of the working device 2 connected to the lifting device 8, and the lifting control device 40 is in the second mode and the first lifting operation tool In the state where the operation of 51A is released, the predetermined position is set to the reference position P1, and the reference elevation control is performed to raise and lower the elevation device 8 so that the elevation device 8 is at the reference position P1. According to this, in a situation in which work is being performed while performing the reference elevation control that raises and lowers the elevation device 8 so that the work device 2 is at the reference position P1, it is possible to operate the elevation operation member 51 during the work. As a result, the work device can be easily moved up and down, and when the operation of the up-and-down operation member 51 is released, the work before the up-and-down operation can be easily resumed.
[0049]
　It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.
Code explanation
[0050]
Reference Signs List 1: work vehicle (tractor)
2: working device
3: vehicle body
8: lifting device
40A: first lifting control unit
40B: second lifting control unit
51: lifting operation member
71: first setting member
72: second setting member
H1 : Upper limit (height upper limit)
P1 : Reference position
The scope of the claims
[Claim 1]
　a vehicle body;
　a lifting device provided on the vehicle body;
　a first setting member for setting a reference position in a height direction of a working device connected to the
　lifting device; a
　first elevation control unit for performing a reference elevation control for raising and lowering the elevation device so that the work device is at the reference position; and stopping the reference elevation control when the elevation operation member is operated during the work. and a second elevation control section that raises and lowers the elevation device according to the operation of the elevation operation member
　,
　wherein the first elevation control section cancels the operation of the elevation operation member after stopping the reference elevation control. a work vehicle that performs control to return the lifting device to a position corresponding to the reference position when the lifting device is set to the reference position.
[Claim 2]
　The work vehicle according to claim 1, wherein the first elevation control unit resumes the reference elevation control after performing control to return the elevation device to a position corresponding to the reference position.
[Claim 3]
　The second elevation control unit, when the elevation operation member is operated, raises or lowers the elevation device within a set range between an upper limit value and a lower limit value of the height that can be set by the first setting member. 3. The work vehicle according to 1 or 2.
[Claim 4]
　A second setting member capable of setting an upper limit value of the height of the lifting device is provided, and
　the second lifting control unit lifts and lowers the lifting device below the upper limit value set by the second setting member. 3. The work vehicle according to 3.
[Claim 5]
　The work vehicle according to any one of claims 1 to 4, wherein the second elevation control section raises and lowers the elevation device during operation of the elevation operation member.
[Claim 6]
　The first setting member is capable of setting a plowing depth of the working device as a reference position of the working device, and the first elevation control unit lifts and lowers the lifting device so that the plowing depth is constant. Item 6. The work vehicle according to any one of items 1 to 5.
[Claim 7]
　a vehicle body;
　a lifting device provided on the vehicle body;
　a first
　lifting operation tool for operating the lifting device to move up and down; an elevation control device that moves the elevation device from the position where the operation is canceled to another position when the operation is canceled
　.
[Claim 8]
　A mode switching member for switching between a first mode and a second mode is provided, and
　in the case of the first mode, the elevation control device raises and lowers the elevation device during operation of the first elevation operation tool. When the operation is canceled, the lifting device is stopped from moving up and down. In the second mode, the lifting device is moved up and down while the first lifting operation tool is being operated, and the operation is canceled. and the lifting device to a predetermined position.
[Claim 9]
　The first elevating operation tool has a first elevating operation section for operating the elevation device and a first descent operating section for operating the descent operation, and the
　elevating control device operates the first elevation operation section. 9. The work vehicle according to claim 7 or 8, wherein the lifting device is lifted during operation of the first lowering operation portion, and the lifting device is lowered during operation of the first lowering operation portion.
[Claim 10]
　A second lifting operation tool having a second lifting operation unit for operating the lifting device and a second lowering operation unit for operating the
　lifting device, and an upper limit value and a lower limit value of the height of the lifting device can be set. and a height setting tool
　,
　wherein the elevation control device raises the elevation device to the upper limit position when the second raising operation section is operated, and raises the elevation device to the upper limit position when the second lowering operation section is operated. 10. The work vehicle according to claim 9, wherein the lifting device is lowered to the lower limit position.
[Claim 11]
　The work vehicle according to claim 10, wherein the first lifting operation tool and the second lowering operation tool are arranged side by side.
[Claim 12]
　A first setting member for setting a reference position in the height direction of the working device connected to the lifting device is provided, and the
　lifting control device is in the second mode and the operation of the first lifting operation tool is canceled. 12. The work according to any one of claims 7 to 11, wherein in a state in which the worker is standing, the predetermined position is set to the reference position, and reference elevation control is performed to raise and lower the elevation device so that the elevation device is at the reference position. vehicle.