JP2011050321A - Tractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tractor which can inhibit the automatic control of inclination on the start of an engine and validates the automatic control of inclination without performing a complicated inhibition-canceling operation to enable the quick restart of work. <P>SOLUTION: The tractor is provided at a control device 32 with lifting or lowering switch control means for lifting or lowering an implement to a prescribed lifting or lowering position by driving and controlling an electric motor 25 according to the operation of a lifting or lowering switch lever 23, and automatic inclination control means for automatically inclining the implement by the switching control of an inclination control valve 14 according to the lateral inclination of a travel machine frame 1 or the implement, wherein the lifting or lowering switch control means can specify the position of a motor operation member on the basis of a pulse output from the electric motor 25, and the control means includes automatic inclination-inhibiting means which inhibits the automatic inclination control on the start of an engine, and automatic inclination inhibition-canceling means for canceling the inhibition of the automatic inclination control according to a prescribed implement-lifting or lowering operation. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tractor including a mechanical position control mechanism that controls the working machine to move up and down in accordance with the operation of a position lever, and an automatic tilt control function that controls the inclination of the working machine in accordance with the horizontal inclination of the traveling machine body or the working machine. About.

  2. Description of the Related Art A tractor having an automatic tilt control function for controlling the tilt of a work machine according to the left / right tilt of a traveling machine body or a work machine is known. In this type of tractor, there is a possibility that the balance of the machine body may be lost when the working machine is tilted in the raised state. Therefore, it is necessary to prohibit the tilting operation of the working machine in the raised state. For example, when the work implement is lifted, the work implement is forcibly returned to the parallel posture and the tilting operation at the raised position is prohibited.

  By the way, some tractors are mechanically linked to a position lever and a lift control valve, and include a mechanical position control mechanism that moves the work implement up and down by switching the lift control valve according to the operation of the position lever. Yes (see, for example, Patent Document 1). Since this type of tractor usually does not include a lift arm sensor, a position switch for detecting the maximum raising operation of the position lever is provided, and the work implement is returned in parallel when the position switch is turned on. The tilting operation is prohibited.

  Some tractors have a lift switch control function for moving the work implement up and down to a predetermined ascending position (for example, an upper limit position) and a descending position (for example, a position position of the position lever) according to the operation of the lifting switch. is there. In order to realize the above-described lift switch control function in a tractor having a mechanical position control mechanism, an electric motor mechanically linked to a lift control valve via a motor operating body and a position control mechanism is provided, and a lift switch It is necessary to drive and control the electric motor according to the operation.

  However, in the above tractor, the work implement may be lifted even when the position switch is OFF. Therefore, the position of the work implement can be grasped by any method other than the position switch, and the parallel return or tilting operation when the work implement is raised. It is necessary to perform prohibition control. For example, an electric motor with a pulse output function that outputs a pulse in accordance with motor driving is employed, and the position of the work machine (motor operating body) is grasped based on the output pulse of the electric motor.

Japanese Patent No. 3810339

  However, the work equipment position information based on the output pulse of the electric motor is held in the memory of the control device and disappears with the engine stop operation (key switch turning operation). There is a risk that the work implement may tilt at the raised position.

The present invention has been created in order to solve these problems in view of the above circumstances, and includes a working machine connected to a traveling machine body so as to be movable up and down and tilted left and right, and a lifting operation of the work machine. Mechanical control that controls the lifting control valve, the manually operated position lever, and the position lever and the lifting control valve, and switches the lifting control valve according to the operation of the position lever to move the working machine up and down. A position control mechanism, and a motor operating body and a position control mechanism, which are mechanically linked to the lift control valve, and by switching the lift control valve with motor power, A tilt control valve that controls the tilt operation, and a control device that electrically controls the electric motor and the tilt control valve. In addition, by driving and controlling the electric motor according to the operation of the lifting switch, the lifting switch control means for raising and lowering the working machine to the predetermined ascending position and the descending position, and tilting according to the left and right inclination of the traveling machine body or the working machine In the tractor provided with the automatic tilt control means for automatically tilting the work implement by switching the control valve, the electric motor has a pulse output function for outputting a pulse in accordance with the motor drive, The elevating switch control means can specify the position of the motor operating body based on a pulse output from the electric motor, and the control device further includes an automatic inclination prohibiting means for prohibiting automatic inclination control when the engine is started, Inclination automatic prohibition canceling means for canceling prohibition of the automatic tilt control according to a predetermined work implement lifting operation is provided.
Further, the automatic tilt prohibition canceling means cancels the prohibition of the automatic tilt control based on the operation of the lift switch and / or the lowering operation from the highest position of the position lever.

According to the first aspect of the present invention, even when the work implement position information (motor operating body position information) based on the output pulse of the electric motor disappears due to the engine stop operation (key switch turning operation), the engine start (key Since automatic tilt control during switch-on operation is prohibited, there is no possibility that the work implement tilts in the raised position. Further, since the prohibition of the automatic tilt control is canceled in accordance with a predetermined work implement ascending / descending operation, the automatic tilt control can be validated and the work can be resumed promptly without performing another complicated prohibition canceling operation.
According to the invention of claim 2, the prohibition of the automatic tilt control can be canceled based on the operation of the up / down switch or the lowering operation of the position lever from the highest position.

It is the whole tractor side view. It is a principal part side view of a tractor. It is a hydraulic circuit diagram of a tractor. It is the perspective view which looked at the mechanical position control mechanism from the left rear. It is the perspective view which looked at the mechanical position control mechanism from the right rear. It is a side view of a mechanical position control mechanism. It is a rear view of a mechanical position control mechanism. It is a front view of a meter panel. It is a block diagram which shows the input / output of a control apparatus. It is a flowchart of motor control. It is a flowchart of motor operation control. It is a flowchart of motor setting control. It is a flowchart of motor stop control. It is a flowchart of inclination automatic control. It is a flowchart of the starting control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a traveling body of a tractor. The traveling body 1 includes an engine mounting portion 2, front wheels 3 and rear wheels 4 driven by engine power, a control portion 5 on which an operator gets on, and the like. Has been.

  As shown in FIG. 2, a work machine (not shown) is connected to the rear portion of the traveling machine body 1 via an elevating link mechanism 6 so as to be movable up and down and tilted left and right. The lift link mechanism 6 is suspended by a lift arm 8 via a pair of left and right lift rods 7 and lifts the work implement according to the hydraulic lift operation of the lift arm 8 and either the left or right lift rod. The work implement is tilted to the left and right according to the hydraulic expansion and contraction operation of the lift rod cylinder 9 interposed between the lift rod cylinder 9 and the lift rod cylinder 9.

  As shown in FIG. 3, the traveling machine body 1 is provided with two hydraulic pumps P1 and P2. One hydraulic pump P1 is for operating the power steering mechanism 10 and the front wheel speed increasing mechanism 11, and the other hydraulic pump P2 is for operating the lift arm 8 and the lift rod cylinder 9. That is, the lift cylinder 13 is hydraulically connected to the hydraulic pump P2 via the lift control valve 12 that is a manual direction switching valve, and according to the hydraulic expansion / contraction operation of the lift cylinder 13 when the lift control valve 12 is switched. Thus, the lift arm 8 moves up and down. Further, a lift rod cylinder 9 is hydraulically connected to the hydraulic pump P2 via a tilt control valve 14 comprising an electromagnetic direction switching valve, and the lift rod cylinder 9 is hydraulically expanded and contracted in response to switching of the tilt control valve 14. It is supposed to work.

  As shown in FIGS. 2 and 4 to 7, the control unit 5 is provided with a position lever 15 that is manually operated. The position lever 15 is a work implement lifting operation tool that sets the lift position of the work implement, and is linked to the lift control valve 12 via a mechanical position control mechanism 16.

  The position control mechanism 16 is mechanically connected to the position lever 15 and the elevation control valve 12 and switches the elevation control valve 12 in accordance with the operation of the position lever 15 to raise and lower the work implement. The position control mechanism 16 of this embodiment is linked to a position arm 17 that follows the position lever 15, a first valve operating shaft 18 that is linked to the position arm 17, a feedback link 19 that feeds back the position of the lift arm 8, and a feedback link 19. The second valve operation shaft 20 and the valve operation shaft 21 that switch the elevation control valve 12 according to the operation of the valve operation shafts 18 and 20 are provided.

  That is, when the position lever 15 is operated, the position arm 17 that follows the position lever 15 switches the lift control valve 12 from the neutral side to the ascending side or the descending side via the first valve operating shaft 18 and the valve operating link 21 to raise and lower the work implement. Let When the work implement is lifted and lowered, the position of the lift arm 8 is fed back to the lift control valve 12 via the feedback link 19, the second valve operating shaft 20 and the valve operating link 21, and the lift arm 8 is moved to the corresponding position of the position lever 15. The lift control valve 12 returns to neutral at the timing of reaching, and the lift of the work implement is stopped. In the figure, reference numeral 22 denotes a tilling depth setting lever linked to a mechanical tilling depth control mechanism.

  The tractor according to the present invention raises and lowers the working machine up and down to a predetermined ascending position (for example, an upper limit position) and a descending position (for example, a set position of the position lever 15) according to the operation of the elevating switch lever (elevating switch) 23. A switch control function is provided. In a tractor having a mechanical position control mechanism 16, in order to realize such a lift switch control function, an electric motor mechanically linked to the lift control valve 12 via the motor operating body 24 and the position control mechanism 16. 25, and it is necessary to drive and control the electric motor 25 in accordance with the operation of the elevation switch lever 23. Therefore, in the present embodiment, the motor operating body 24 is connected to the position arm 17 via the accommodation mechanism, so that the operation of the position arm 17 according to the operation of the position lever 15 is allowed, and at the time of lift switch control, The position arm 17 is operated by the driving force of the motor 25.

  The electric motor 25 incorporates a speed reduction mechanism and has a pulse output function for outputting a pulse in accordance with motor driving. For example, it is assumed that N pulses are output every rotation of the motor output shaft. According to such an electric motor 25, it is possible to specify the position of the motor operating body 24 by counting pulses output in accordance with motor driving.

  In the present embodiment, when the electric motor 25 is attached to the motor fixing member 26, the motor fixing member 26 is also used as a retaining member for the motor operating body 24. That is, the electric motor 25 of this embodiment has a quadrangular prism-shaped motor output shaft (not shown), and the motor output body 24 is connected to the square hole of the motor operating body 24 in a fitting manner. Then, by fixing the electric motor 25 to the motor fixing member 26 so that the motor operating body 24 is sandwiched between the electric motor 25 and the motor fixing member 26, the motor operating body 24 is retained by the motor fixing member 26. It has come to be.

  The control unit 5 is provided with a meter panel M. As shown in FIG. 8, in the meter panel M, meters such as an engine tachometer 27, a fuel gauge 28, and a water temperature gauge 29 are provided, an automatic inclination lamp 30 for displaying a control state of automatic inclination control, work Lamps such as a lift-up lamp 31 for displaying the lift-up state of the machine are provided.

  The tractor according to the present invention includes a control device 32 for controlling the tilt control valve 14 and the electric motor 25. As shown in FIG. 9, on the input side of the control device 32, in addition to the elevation switch lever 23 and the pulse output terminal of the electric motor 25, an automatic tilt switch 33 that switches the control state of the automatic tilt control, the position lever 15. A position switch 34 for detecting the highest lifting operation, an inclination setting volume 35 for setting a target inclination for automatic inclination control, an engine rotation sensor 36 for detecting engine rotation, a lift rod sensor 37 for detecting an operating position of the lift rod cylinder 9, An inclination sensor 38 for detecting the left / right inclination of the traveling machine body 1 is connected. On the output side of the control device 32, the extension solenoid 14a, the reduction solenoid 14b of the inclination control valve 14 described above, and the motor of the electric motor 25 are connected. In addition to drive relay 25a, automatic ramp 30 and lift-up ramp 31, alarm Such as a buzzer 39 that emits is connected.

  The control device 32 drives and controls the electric motor 25 in accordance with the operation of the lift switch lever 23, thereby moving the work implement up and down to predetermined lift and drop positions (motor control, motor operation control, Motor setting control and motor stop control) and automatic inclination control means (inclination automatic control) for automatically inclining the work implement by switching the inclination control valve 14 according to the right and left inclination of the traveling machine body 1. Prepare.

  The lift switch control means can determine the position of the motor operating body 24 and the work implement based on the output pulse of the electric motor 25. However, the position grasping by the motor output pulse may cause a deviation from the actual position due to a cumulative error of the pulse counter. Therefore, when the work implement is stopped at a predetermined ascending position or descending position, a necessary position is required. There is a possibility that accuracy cannot be secured. In particular, since the raised position of the work implement is strictly set to avoid interference with the cabin or the like, the stop position is not allowed to deviate greatly.

  Although it is conceivable that the motor operating body 24 is operated to the mechanical locking positions on the ascending side and the descending side to ensure the necessary positional accuracy, if the electric motor 25 is locked on the ascending side and the descending side, There is a possibility that overheating of the motor 25 and generation of electrical noise become problems, and mechanical fatigue is accumulated, resulting in failure.

  Therefore, the lift switch control means according to the embodiment of the present invention specifies the position of the motor operating body 24 based on the pulse output from the electric motor 25, and the motor operating body according to the raising operation of the lift switch lever 23. When actuating 24 to the ascending side, the motor actuating body 24 is actuated to the mechanical lock position on the ascending side, and when the motor actuating body 24 is actuated to the descending side according to the descending operation of the elevation switch lever 23. Operates the motor actuating body 24 to a predetermined position on the lower side specified based on the output pulse of the electric motor 25. That is, on the ascending side where high accuracy is required, the motor operating body 24 is operated to the ascending mechanical lock position, and on the descending side where high accuracy is not required, it is specified based on the output pulse of the electric motor 25. Since the motor operating body 24 is operated to a predetermined position on the lowering side, the number of locks of the electric motor 25 can be reduced while satisfying the required accuracy.

  Further, the lift switch control means according to the embodiment of the present invention stops the motor actuating body 24 after outputting the lock position specifying pulse number (for example, 50 pulses) specifying the ascending mechanical lock position and the stop command. Stop delay pulse number (for example, 6 pulses) corresponding to the time until the start time and lock time pulse number (for example, 3 pulses) corresponding to the time for locking the motor operating body 24 at the ascending mechanical lock position ) And the motor operating body 24 is operated from the lower position (for example, 10 pulses) to the upper mechanical lock position, the number of pulses corresponding to the lock time is added to the lock position specific number of pulses. The number of pulses (for example, 47 pulses = 53 pulses−6 pulses) obtained by subtracting the number of pulses for stop delay from the number of pulses (for example, 53 pulses = 50 pulses + 3 pulses) is calculated. Luz number outputs a stop command of the electric motor 25 by the count timing. In this way, the lock time of the electric motor 25 can be shortened as much as possible while the motor operating body 24 is reliably operated to the ascending mechanical lock position. In the above example, it is assumed that the pulse counter is counted up when the work implement is raised, and the pulse counter is counted down when the work implement is lowered. Conversely, the pulse counter is counted down when the work implement is raised. The pulse counter may be counted up when descending.

  Hereinafter, motor control, motor operation control, motor setting control, and motor stop control of the present embodiment that realize the above-described lift switch control means will be described with reference to FIGS.

  The motor control shown in FIG. 10 is a process of setting “up” or “down” to the quick up flag (motor drive flag) according to the operation of the up / down switch lever 23 or the like. First, it is determined whether the position switch 34 is OFF. (S101). If this determination result is YES, it is determined whether or not the position switch 34 has changed from ON to OFF (S102). If this determination result is also YES, "down" is set to the quick up flag (S103). ). That is, when the position lever 15 is operated from the highest position to the lower side, the electric motor 25 is driven to the lower side in order to return the motor operating body 24 to the lower position, which is the initial position.

  If the position switch 34 is OFF (S101) and the engine is rotating (S104), the raising / lowering operation of the raising / lowering switch lever 23 is judged (S105, S107). Here, the raising / lowering switch lever 23 is lowered. When it is determined that it has been operated (S105), the quick-up flag is set to “lower” (S106), while when it is determined that the lift switch lever 23 has been operated to be raised (S107), the quick-up flag is set to “raise”. Is set (S108). That is, when the position lever 15 is on the lowering side and the engine is in a rotating state, the electric motor 25 is moved upward to raise or lower the work implement to a predetermined ascending or descending position according to the operation of the elevating switch lever 23. Alternatively, it is driven downward.

  The motor operation control shown in FIG. 11 is a process for driving and stopping the electric motor 25 according to a quick-up flag or the like. First, it is determined whether or not the electric motor 25 is in a stopped state (S201). If the determination result is YES, the quick-up flag and the motor state are compared, and it is determined whether or not the two are different (S202). If this determination result is YES, it is determined whether the quick-up flag is “raised” or “lowered” (S203, S204). If the quick-up flag is “raised”, a motor up output command and a motor operation timer are set. If the quick up flag is “decrease” (S205), a motor lowering output command and a motor operation timer are set (S206). When the motor raising command is set (S207), the electric motor 25 is driven upward (S208). When the motor lowering command is set (S209), the electric motor 25 is driven downward (S210). In other states, the electric motor 25 is stopped (S211).

  The motor setting control shown in FIG. 12 is a process for stopping the electric motor 25 and clearing the motor ascending command and the motor descending command as the motor operation timer elapses. First, the motor operation timer is set to “0”. It is determined whether or not (S301). If the determination result is YES, it is determined whether the motor is driven by a motor up command or a motor down command (S302, S303). If it is a motor up command, the motor is stopped and the motor up command is cleared. (S304), the motor upper limit is set (S305), and if it is a motor lowering command, the motor is stopped and the motor lowering command is cleared (S306). The motor upper limit setting is the pulse counter value when the ascending drive of the electric motor 25 is stopped according to the elapse of the motor operation timer, that is, when the motor operating body 24 is operated to the ascending mechanical lock position. This is a setting process for obtaining the upper limit position specific pulse number (or setting the upper limit position specific pulse number in the pulse counter value), and is normally performed only once after the engine is started.

  The motor stop control shown in FIG. 13 is a process for stopping the work implement (motor operating body 24) at a predetermined ascending position or descending position. First, the motor is driven by either a motor ascending command or a motor descending command. Is determined (S401, S402). Here, if it is determined that the motor increase command is received, the increase stop determination pulse number U is compared with the current pulse counter value, and when the current pulse counter value exceeds the increase stop determination pulse number U (S403). ), Motor stop and motor lift command are cleared (S404). The ascending stop determination pulse number U is the number of pulses obtained by adding the number of pulses corresponding to the lock time to the number of lock position specific pulses described above, and subtracting the number of stop delay pulses, thereby raising the motor operating body 24. The lock time of the electric motor 25 can be shortened as much as possible while reliably operating to the mechanical lock position on the side. If it is determined that it is a motor lowering command, the descent stop determination pulse number D is compared with the current pulse counter value, and the current pulse counter value exceeds the descent stop determination pulse number D (S405). Then, the motor stop and motor lowering commands are cleared (S406). The descending stop determination pulse number D is a position set based on the above-described lock position specific pulse number, and is set so that the motor operating body 24 does not reach the descending mechanical lock position.

  Next, the automatic tilt control executed by the control device 32 according to the embodiment of the present invention will be described.

  When the work implement is automatically tilt-controlled according to the left-right tilt of the traveling machine body 1, if the work machine is tilted in the raised state, the balance of the machine body may be lost. It is necessary to ban. For example, when it is determined that the working machine is lifted based on the position switch 34 being turned on, the working machine is forcibly returned to the parallel posture and the tilting operation at the raised position is prohibited.

  Further, in the tractor according to the present embodiment in which the lifting / lowering switch lever 23 can be used to lift and lower the working machine, the working machine may be lifted even when the position switch 34 is OFF. It is necessary to grasp the position of the work implement, and to perform parallel return and tilt control prohibition control when the work implement is raised. For example, a method of grasping the rise of the work implement (motor operating body 24) based on the output pulse of the electric motor 25 and a method of grasping the rise of the work implement based on the raising operation of the lift switch lever 23 can be mentioned.

  However, the work machine position information based on the output pulse of the electric motor 25 is held in the memory of the control device 32 and disappears with the engine stop operation (key switch turning operation). There is a risk that the work implement may tilt at the raised position during switch-on operation.

  Accordingly, the control device 32 according to the embodiment of the present invention cancels the prohibition of the automatic inclination control according to the automatic inclination control means (startup control) for prohibiting the automatic inclination control at the time of starting the engine and the predetermined work implement lifting operation. Inclination automatic prohibition canceling means (startup control). In this way, even if the work implement position information (motor operating body position information) based on the output pulse of the electric motor 25 disappears due to the engine stop operation (key switch turning operation), the engine is started (key switch entering operation). Automatic tilt control at the time) is prohibited, so there is no fear that the work implement tilts in the raised position. Further, since the prohibition of the automatic tilt control is canceled according to a predetermined work implement lifting operation, the automatic tilt control is enabled without performing a separate complicated prohibition canceling operation (for example, multiple operations of the automatic tilt switch 33), Work can be resumed promptly. In addition, in the present embodiment, the prohibition of the automatic tilt control is canceled based on the operation of the lift switch lever 23 or the lowering operation of the position lever 15 from the highest position, so that the position of the work implement is reliably grasped. Automatic tilt control can be enabled.

  Hereinafter, the automatic tilt control and the start-time control according to the present embodiment for realizing the above functions will be described with reference to FIGS. 14 and 15.

  As shown in FIG. 14, in the automatic tilt control, first, it is determined that the coupler of the lift rod sensor 37 is disconnected (S501), and then the operation of the automatic tilt switch 33 (OFF → ON) is determined (S502). If the result of this determination is YES, the state of automatic tilt control is reversed (S503). For example, when the automatic tilt control 33 is operated when the automatic tilt control is OFF, the automatic tilt control is switched to the ON state. When the automatic tilt switch 33 is operated when the automatic tilt control is ON, the automatic tilt control is switched to the OFF state.

  Next, it is determined whether the position lever 15 is fully raised and the elevation switch lever 23 is raised (S504, S505). Here, if any of the determination results is YES, it is determined whether or not the work implement is to be returned in parallel (S506). If the determination result is YES, the parallel return position is set to the target lift rod sensor value. Then, the work machine is returned to the parallel state (S507). In addition, after the completion of the parallel return (or the parallel return restricted state), the tilting operation of the work implement is kept in a stopped state (S508).

  On the other hand, in a state where the position lever 15 is not fully raised and the elevation switch lever 23 is not raised, it is determined whether or not “TRUE” is set in the tilt prohibition flag (S509), and the determination result is YES. Keeps the tilting operation of the work implement in a stopped state (S508). If the determination result is NO, the work implement is automatically tilted according to the left / right tilt of the machine body (S510).

  The start-up control shown in FIG. 15 is a process for prohibiting the automatic tilt control at the time of starting the engine and canceling the prohibition of the automatic tilt control in accordance with a predetermined work implement raising / lowering operation. As a setting (initial setting), “TRUE” is set in the tilt prohibition flag (S601). Next, it is determined whether or not the position switch 34 is OFF (S602). If the determination result is YES, it is determined whether or not the position switch 34 is switched from ON to OFF (S603). ). That is, it is determined whether or not the position lever 15 has been lowered from the highest position. If the determination result is YES, the tilt prohibition flag is set to “FALSE” and the automatic tilt control prohibition state is canceled ( S604).

  On the other hand, if the prohibition cancellation condition is not satisfied, after confirming that the engine is rotating (S605), the operation of the lift switch lever 23 is determined (S606, S607). When it is determined that the up / down switch lever 23 has been raised or lowered, "FALSE" is set in the inclination prohibition flag, and the prohibition state of the automatic inclination control is canceled (S608, S609).

  In a state where “TRUE” is set in the tilt prohibition flag, it is preferable to perform some notification operation in order to notify the operator of the prohibition state of the automatic tilt control. For example, it is possible to notify the operator of the prohibition state of the automatic inclination control by blinking the automatic inclination lamp 30 and the lift-up lamp 31 and blowing the buzzer 39. If it does in this way, work will be started in the state where tilt automatic control does not work, and the problem that work accuracy falls can be solved.

  According to the present embodiment configured as described, the working machine connected to the traveling machine body 1 so as to be able to be raised and lowered and tilted to the left and right, the raising and lowering control valve 12 that controls the raising and lowering operation of the working machine, and the manually operated position lever 15. And a mechanical position control mechanism 16 that is mechanically connected to the position lever 15 and the elevation control valve 12 and switches the elevation control valve 12 in accordance with the operation of the position lever 15 to move the working machine up and down. An electric motor 25 that is mechanically linked to the lift control valve 12 via the operating body 24 and the position control mechanism 16 and switches the lift control valve 12 with motor power to move the work machine up and down, and a tilting operation of the work machine An inclination control valve 14 that controls the electric motor 25 and a control device 32 that electrically controls the inclination control valve 14. Further, the control device 32 controls the drive of the electric motor 25 according to the operation of the lift switch lever 23, thereby moving the working machine up and down to a predetermined ascending position and descending position, and the traveling machine body 1. Alternatively, in the tractor provided with the automatic tilt control means for automatically tilting the work implement by switching the tilt control valve 14 according to the left / right tilt of the work implement, the electric motor 25 is operated according to the motor drive. It has a pulse output function for outputting a pulse, and the lift switch control means can specify the position of the motor operating body based on the pulse output from the electric motor 25. Further, the control device 32 is inclined when the engine is started. Inclination automatic prohibition means for prohibiting automatic control, and automatic inclination prohibition solution for canceling prohibition of automatic inclination control in response to a predetermined lifting operation of the work implement Even if the work machine position information (motor operating body position information) based on the output pulse of the electric motor 25 disappears due to the engine stop operation (key switch turning operation), the engine is started (with the key switch on) Automatic tilt control during operation is prohibited, and there is no possibility that the work implement tilts in the raised position. Further, since the prohibition of the automatic tilt control is canceled in accordance with a predetermined work implement ascending / descending operation, the automatic tilt control can be validated and the work can be resumed promptly without performing another complicated prohibition canceling operation.

  Further, the automatic tilt prohibition canceling means cancels the prohibition of the automatic tilt control based on the operation of the elevating switch lever 23 and / or the lowering operation of the position lever 15 from the highest position. It is possible to cancel the prohibition of the automatic tilt control while grasping the above.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 12 Elevation control valve 14 Inclination control valve 15 Position lever 16 Position control mechanism 23 Elevation switch lever 24 Motor action body 25 Electric motor 32 Controller 34 Position switch

Claims (2)

A working machine connected to the traveling machine body so as to be movable up and down and left and right;
A lift control valve that controls the lifting and lowering operation of the work machine,
An artificially operated position lever;
A mechanical position control mechanism that is mechanically linked to the position lever and the lift control valve, and moves the work implement up and down by switching the lift control valve according to the operation of the position lever;
An electric motor that is mechanically linked to the lift control valve via a motor operating body and a position control mechanism, and that moves the work implement up and down by switching the lift control valve with motor power;
A tilt control valve that controls the tilting operation of the work implement;
A control device for electrically controlling the electric motor and the tilt control valve;
In the control device,
A lift switch control means for driving the electric machine up and down to a predetermined ascending position and a descending position by driving and controlling the electric motor according to the operation of the elevating switch;
In a tractor provided with a tilt automatic control means for automatically tilting the work machine by switching and controlling the tilt control valve according to the left and right tilt of the traveling machine body or the work machine
The electric motor is
Has a pulse output function to output pulses according to the motor drive,
The elevating switch control means includes
The position of the motor operating body can be specified based on the pulse output from the electric motor,
Further, the control device includes:
Inclination automatic prohibition means for prohibiting automatic inclination control when starting the engine,
A tractor comprising: an automatic inclination prohibition canceling means for canceling prohibition of the automatic inclination control in accordance with a predetermined work implement lifting operation. The tilt automatic prohibition releasing means is
The tractor according to claim 1, wherein the prohibition of the automatic tilt control is canceled based on an operation of the lift switch and / or a lowering operation of the position lever from the highest position.

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