JP2013111010A - Farm implement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a farm implement equipped with an implement such as a plow 12 prevented from descending in no time.SOLUTION: The tractor is equipped with an automatically plowing-controlling function for outputting hydraulic fluid for a lift cylinder 17 to a lowering side of a lift arm 19 at the maximum flow rate when an implement-lifting and lowering switch 23 is kept in a state of being pushed to the lowering side, and a controller 50 having a controlling structure for prohibiting the automatic plowing control when a car speed detected by a car speed sensor 24 and not lower than a prescribed car speed is not detected. As a result, at the time when the automatic plowing control is not necessary including the time or the like for attaching and detaching the implement, the risk such as the one of breaking the implement and asphalt by the rapid lowering of the lift arm 19 is avoided even if wrong operation is carried out.

Description

  The present invention relates to an agricultural machine such as a tractor provided with a plow 12 that can accurately perform tillage work on soil.

  A tractor equipped with a plow or other work implement on the tractor and plowing work at a fixed plowing depth with respect to the soil is a draft that can raise and lower the work implement automatically according to the work load and perform stable work. A configuration having a control function is known.

  The draft control function is necessary to prevent the following problems. That is, when an overload exceeding the traction force of the tractor is applied to the work implement, the front wheel is lifted, and the tractor loses the traction force when only the rear wheel is grounded. In addition, when a tilling operation is performed in an overload state in which the front wheels of the tractor do not float up, the work machine may be damaged if the tractor is forcibly pulled by the tractor. In order to prevent such troubles, some tractors are equipped with a draft control mechanism.

JP 2001-169606 A

  The tractor is equipped with a plow via a three-point link mechanism, and the draft control is performed by moving the three-point link mechanism up and down by a hydraulic lift cylinder.

  Also, when lowering the plow, the draft control mechanism can be activated by operating the lift cylinder with hydraulic fluid at the maximum flow rate by continuing to push the lift switch of the work implement in the control section downward. Especially, it is effective when it is difficult for the working machine to enter the soil during plowing.

  Therefore, a function to operate the lift cylinder with the maximum flow rate of hydraulic fluid is necessary, but on the other hand, the work implement may fall down at once due to incorrect operation when the work implement is attached or detached, etc. The problem of damaging the asphalt above has been pointed out.

  Then, the subject of this invention is providing the agricultural working machine equipped with the working machine which prevents working machines, such as a plow, falling at a stretch.

The above-described problems of the present invention are solved by the following solution means.
According to the first aspect of the present invention, there is provided a hydraulic lift cylinder (17) for raising and lowering the work machine (12) mounted on the rear part of the tractor body (10), and hydraulic oil for operating the lift cylinder (17) to the upward side. Lift arm lift solenoid (32) that sends out hydraulic fluid, lift arm lower solenoid (33) that sends hydraulic fluid that operates the lift cylinder (17) to the lower side, lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), work Working machine lifting switch (23) for raising and lowering the machine, lift arm sensor (49) for detecting raising and lowering of the lift arm (19), load sensor (7) for performing draft control of the working machine, tractor body (10 ) Vehicle speed sensor (24) for detecting the vehicle speed, forward / reverse lever (37) for controlling forward / backward movement of the tractor body (10), or a forward / reverse switch (4 ), A forward / reverse lever sensor (38) for detecting the operation position of the forward / reverse lever (37), a travel transmission device of the tractor body (10), and a travel mode switch (39) for switching the travel mode of the travel transmission device. The automatic squeeze control function for outputting the lift arm (19) to the lower side at the maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side in the tractor, and a vehicle speed sensor When a vehicle speed of substantially zero (which differs depending on the model, the slowest working speed, and the vehicle body is substantially stopped) is detected by (24), a control device (50 having a control function for prohibiting the automatic plow control) ).

 According to a second aspect of the present invention, there is provided a hydraulic lift cylinder (17) for raising and lowering the work machine (12) mounted on the rear portion of the tractor body (10), and hydraulic oil for operating the lift cylinder (17) to the upward side. Lift arm raising solenoid (32) to be sent out, lift arm lowering solenoid (33) to send hydraulic oil for operating the lift cylinder (17) to the lowering side, lift arm (19) to be raised and lowered by the expansion and contraction of the lift cylinder (17), working machine Lift switch (23), lift arm sensor (49) for detecting the lifting / lowering of the lift arm (19), load sensor (7) for performing draft control of the work implement, and vehicle speed sensor for detecting the vehicle speed of the tractor body (10) (24), a forward / reverse lever (37) or a forward / reverse switch (43) for controlling forward / backward movement of the tractor body (10), a forward / reverse lever (3 ) In the tractor provided with the forward / reverse lever sensor (38) for detecting the operation position of), the travel transmission device of the tractor body (10), and the travel mode switch (39) for switching the travel mode of the travel transmission device. When the switch (23) is continuously pushed down, the hydraulic fluid in the lift cylinder (17) outputs the lift arm (19) to the down side at the maximum flow rate, and the forward / reverse lever sensor (38) A control device having a control function for prohibiting the automatic scavenging control when it is detected that the operating position of the advance lever (37) is not in the forward side or when the forward / reverse switch (43) is not in the forward side A tractor comprising (50).

  The invention according to claim 3 is a hydraulic lift cylinder (17) for raising and lowering the work machine (12) mounted on the rear part of the tractor body (10), and hydraulic oil for operating the lift cylinder (17) to the ascending side. Lift arm lift solenoid (32) that sends out hydraulic fluid, lift arm lower solenoid (33) that sends hydraulic fluid that operates the lift cylinder (17) to the lower side, lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), work Vehicle lift switch (23), lift arm sensor (49) for detecting the lift of the lift arm (19), load sensor (7) for performing draft control of the work machine, vehicle speed for detecting the vehicle speed of the tractor body (10) Sensor (24), forward / reverse lever (37) or forward / reverse switch (43) for controlling forward / backward movement of the tractor body (10), forward / reverse lever ( 7) In a tractor comprising a forward / reverse lever sensor (38) for detecting the operation position of 7), a travel transmission device of the tractor body (10), and a travel mode changeover switch (39) for switching the travel mode of the travel transmission device. When the lift switch (23) is continuously pushed down, the hydraulic fluid in the lift cylinder (17) outputs the lift arm (19) to the down side at the maximum flow rate, and detection by the lift arm sensor (49) Control that prohibits the automatic plowing control except when the working machine is lowered to a predetermined height (the predetermined height differs depending on the model, and the predetermined height here is a workable height). A tractor comprising a control device (50) having a function.

  The invention according to claim 4 is a hydraulic lift cylinder (17) for raising and lowering the work machine (12) mounted on the rear portion of the tractor body (10), and hydraulic oil for operating the lift cylinder (17) to the upward side. Lift arm lift solenoid (32) that sends out hydraulic fluid, lift arm lower solenoid (33) that sends hydraulic fluid that operates the lift cylinder (17) to the lower side, lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), work Vehicle lift switch (23), lift arm sensor (49) for detecting the lift of the lift arm (19), load sensor (7) for performing draft control of the work machine, vehicle speed for detecting the vehicle speed of the tractor body (10) Sensor 24, forward / reverse lever (37) or forward / reverse switch (43) for controlling forward / backward movement of the tractor body (10), forward / reverse lever (37 In a tractor provided with a forward / reverse lever sensor (38) for detecting the operation position of the vehicle, a travel transmission device of the tractor body (10), and a travel mode switch (39) for switching the travel mode of the travel transmission device, If the hydraulic oil in the lift cylinder (17) is output at the maximum flow rate and the lift sensor (19) is output to the lower side when the pressure (23) continues to be pushed downward, and the load sensor (7), the working machine (12 The tractor is provided with a control device (50) having a control function for prohibiting the automatic scavenging control when the draft control is not performed.

  According to a fifth aspect of the present invention, there is provided a hydraulic lift cylinder (17) for raising and lowering the work implement (12) mounted on the rear portion of the tractor body (10), and hydraulic oil for operating the lift cylinder (17) to the upward side. Lift arm raising solenoid (32) to be sent out, lift arm lowering solenoid (33) to send hydraulic oil for operating the lift cylinder (17) to the lowering side, lift arm (19) to be raised and lowered by the expansion and contraction of the lift cylinder (17), working machine Lift switch (23), lift arm sensor (49) for detecting the lifting / lowering of the lift arm (19), load sensor (7) for performing draft control of the work implement, and vehicle speed sensor for detecting the vehicle speed of the tractor body (10) (24), a forward / reverse lever (37) or a forward / reverse switch (43) for controlling forward / backward movement of the tractor body (10), a forward / reverse lever (3 ) In the tractor provided with the forward / reverse lever sensor (38) for detecting the operation position of), the travel transmission device of the tractor body (10), and the travel mode switch (39) for switching the travel mode of the travel transmission device. When the switch (23) is continuously pushed down, the hydraulic fluid in the lift cylinder (17) outputs the lift arm (19) to the down side at the maximum flow rate, and the auxiliary shift “on the road” sensor (42) Provided with a control device (50) having a control function for prohibiting the automatic scavenging control function when detecting the on-road travel position of the auxiliary transmission or when the travel mode switch (39) is at the on-road travel position. It is a tractor characterized by.

  According to the first aspect of the present invention, when the vehicle speed sensor (24) detects that the vehicle speed is substantially zero (which differs depending on the model, the slowest working speed, and the vehicle body is substantially stopped), the automatic scavenging is performed. Since it has a control configuration that prohibits control, it is possible to prevent this control function from working when the automatic plowing control is unnecessary, including when the work implement is attached and detached, and even if it is operated incorrectly, the lift arm ( The risk of 19) descending and breaking the work equipment and asphalt is eliminated.

  According to the second aspect of the present invention, when the forward / reverse lever sensor (38) detects that the forward / reverse lever (37) is not in the forward side, the automatic scooping control is prohibited, so that an actually necessary scene is required. Only the automatic plow control function can be activated. In addition, since it does not function in situations where it is not necessary, such as when the work implement is attached / detached, it will not drop suddenly and break the work implement or asphalt even if it is operated incorrectly.

  According to the third aspect of the present invention, the automatic plow control does not function except when the lift arm (19) is lowered so that the work implement is below a predetermined height. There is no fear that the machine will be lowered from a high position at once, and the work machine and road asphalt will be broken.

  According to the fourth aspect of the present invention, the automatic scavenging control does not function when it is not in the draft control mode, so that the control function can be used only in a scene that is actually necessary. Further, since it does not function in an unnecessary scene such as when the work machine is attached / detached, even if it is erroneously operated, there is no possibility that the work machine, asphalt, etc. are broken suddenly.

  According to the fifth aspect of the present invention, when the sub-shift “on-road” sensor (42) detects the on-road travel position of the sub-transmission device, or when the travel mode switch (39) is at the on-road travel position, automatic By preventing the plowing control from functioning, even if the work implement lift switch (23) is accidentally pushed down when traveling on the road, the work implement will not be lowered at a stretch, and stable travel is possible. Become.

It is the whole riding type rice transplanter which is one Example of the present invention. It is a control block diagram of the tractor drive part of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention. It is a control flowchart figure of one Example of this invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a side view of the tractor body 10, and a working machine 12 such as a plow is connected to the rear portion of the tractor body 10 via a link mechanism 11. The link mechanism 11 includes a top link 13 and left and right lower links 14, 14. A cylinder case 16 is provided at the upper part of the transmission case 15. A lift cylinder 17 is accommodated in the cylinder case 16. A lift control valve 18 is attached to the top.

  Further, lift arms 19 and 19 are pivotally attached to both the left and right sides of the cylinder case 16, and the tip ends of the left and right lift arms 19 and 19 are connected to the left and right lower links 14 and 14 by lift rods 20 and 20. As will be described later, the lift control valve 18 is switched by a lift arm raising solenoid 32 that sends hydraulic fluid that operates the lift cylinder 17 to the upward side and a lift arm lower solenoid 33 that sends hydraulic fluid that operates the lift cylinder 17 to the downward side. Accordingly, when the lift cylinder 17 is driven to extend and contract, the lift arms 19 and 19 rotate up and down around the lift arm shaft 19a around the lift arm shaft 19a, and the lower links 14 and 14 are moved via the lift rods 20 and 20, respectively. Move up and down. Thus, the plow (working machine) 12 moves up and down with the tip ends of the lower links 14 and 14 as the center of rotation.

On the other hand, a work machine position lever 30 that is a means for changing the height of the work machine 12 such as a plow is provided in the vicinity of the driver seat 23.
Although details are omitted, when the work machine position lever 30 is moved to the rear side of the machine body (arrow a (FIG. 1)), the lift control valve 18 is switched to a position where the lift arm 19 is raised, and the lift cylinder 17 is extended. The lift arms 19, 19 are pivoted clockwise about the pivot shafts 19a, 19a, and the lift arms 19, 19 are raised. Further, when the work machine position lever 30 is moved to the front side of the machine body, the lift arms 19 and 19 are lowered.

  A draft ratio adjustment dial 53, which is a dial for adjusting the sensitivity of the draft control, is arranged in the vicinity of the cockpit. When the draft ratio adjustment dial 53 is turned to the left, it is set to the position side, and when it is turned to the right, the draft side is set. The left side) controls to maintain the set tillage depth regardless of the load. Further, when the draft ratio adjustment dial 53 is turned to the right, load priority is given. That is, when a load greater than a predetermined value acts on the work implement, control is performed such that the lift cylinder 17 of the work implement 12 is slightly raised in order to reduce the load below the working depth. Therefore, the draft ratio can be adjusted according to the state of the field and the preference of the operator. As the position is turned to the left (left), the amount of change in the lifting / lowering of the work machine 12 with respect to the load decreases, and priority is given to the plowing depth. As the draft is turned to the right (right), the amount of change in the lifting / lowering of the work machine 12 with respect to the load increases, and the load is reduced.

FIG. 2 shows a control block diagram of a tractor driving portion related to the present embodiment.
A lift arm sensor 49 for detecting the lift angle of the seesaw type work machine lift switch 23 and the lift arm 19 on the lowering side and the raising side, a vehicle speed sensor 24, a sensor 30a of the work machine position lever 30, and the like are input to the controller 50. From 50, a control valve (not shown) that opens and closes hydraulic oil to and from the lift cylinder 17 is controlled to open and close, and is output to the lift solenoid valve and the lower solenoid valve of the lift arm 19.

  In the present embodiment, as shown in the flowchart of FIG. 3, a work implement lifting switch 23 comprising a seesaw switch that can be switched between a lowering side and a raising side is provided in the control unit, and the operator pushes the working machine lifting switch 23 downward. Continuing, with respect to a control function for raising and lowering the lift arm 19 on the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder 17, a predetermined vehicle speed (eg, substantially zero, that is, the sub-shift low speed, the main shift first speed, etc. When the vehicle speed sensor 24 does not detect the slowest working speed (substantially in a stopped state), a control configuration for prohibiting this function is provided.

  The tractor according to the present invention originally has an automatic scavenging control function in which hydraulic oil to the lift cylinder 17 is output at a maximum flow rate when the work implement lifting switch 23 is continuously pushed downward. The function is the draft length or time of the plow 12 when the plow 12 is lowered from the highest position when the work machine (plow) 12 does not enter the soil at the time of plowing in draft control such as plow work. (In the plow 12, the penetration length, that is, the digging depth is important, and the plow 12 has a constant ascending / descending speed, so time may be used instead of the length). .

  This automatic plowing control function is necessary, but on the other hand, the work implement such as the plow 12 may be lowered at a stretch due to erroneous operation when the work implement such as the plow 12 is attached or detached, or the work implement may be damaged. It has been pointed out that there is a risk of damaging paving asphalt, etc.

  Therefore, in the present embodiment, the automatic plow control function is prohibited when a vehicle speed of a predetermined speed (different for each model) is not detected. In addition, since the above control function does not work in situations where it is not necessary to attach or detach the work implement, the lift arm 19 will not be suddenly lowered even if operated incorrectly, and the work implement or asphalt will not be destroyed. If not, the buzzer 26 is sounded and a warning is displayed on the liquid crystal display unit 27, for example, “Please lift and lower the working machine with the working machine position lever 30”.

  Further, in the automatic scavenging control function, as shown in the flowchart of FIG. 4, the vehicle speed sensor 24 relates to a control function for performing a lowering lift output at a maximum flow rate when the lowering switch of the work implement lifting switch 23 is continuously pressed. Regardless of whether or not the vehicle speed is detected (the plowing operation is an operation only during forward movement and is not related to the vehicle speed sensor value), the forward / reverse lever sensor 38 detects that the forward / reverse lever 37 has not entered the forward side. Then, when it is detected that the forward / reverse switch 43 is not in the forward side, the control configuration may be such that the control is prohibited. Further, not only by sounding the buzzer 26, but also by displaying a warning message on the liquid crystal display unit 27 provided in the control unit, for example, “please raise and lower the working machine with the position lever 30”. Become safe.

  As described above, it has been pointed out that the work machine descends at a stroke due to an erroneous operation when the work machine is attached / detached, etc., and that the work machine is damaged or the paving asphalt is damaged. The automatic plow control function is enabled only when shifting to the side, and prohibited when the forward / reverse lever 37 is not shifted to the forward side. Can work. In addition, since it does not function in situations where it is not necessary, such as when the work implement is attached / detached, it will not drop suddenly and break the work implement or asphalt even if it is operated incorrectly.

  In addition, the automatic scavenging control function that outputs the lift arm 19 to the lower side at the maximum flow rate of the hydraulic fluid is such that the working machine is below a predetermined height (depending on the model) as shown in the flowchart of FIG. The lift arm 19 does not function except when it is lowered. At this time, it is desirable to alert the operator by sounding the buzzer 26. Further, it is further safer to display warning contents on the liquid crystal display unit 27 provided in the control unit, for example, “Please lift and lower the working machine with the position lever 30”. This is to prevent the work machine or the asphalt of the road from being broken by lowering the work machine from a high position at once.

In addition, even if the work machine is lowered to a predetermined height and the machine body is stopped, even if the lowering is continuously pushed down, the work machine is not lowered at a stretch. Therefore, there is no problem even if the vehicle speed detection of the vehicle speed sensor 24 is not associated. However, since the hydraulic pressure relief of the lift cylinder 17 is activated, the detection value of the vehicle speed sensor 24 may be taken into consideration for the automatic clearance control.
Further, as shown in the flowchart of FIG. 6, the automatic scavenging control function is disabled when the control mode is not the draft mode.

  If the control mode is not the draft mode, it is desirable to sound the buzzer 26 to alert the operator. Further, it is further safer to display warning contents on the liquid crystal display unit 27 provided in the control unit, for example, “Please lift and lower the working machine with the position lever 30”.

By enabling the automatic plow control function only when the control mode is the draft mode, the control function can be operated only when actually required. In addition, since it does not function in an unnecessary scene such as when the work machine is attached / detached, the work machine, asphalt, or the like will not be broken suddenly even if an erroneous operation is performed.
Even if the switch relationship is a draft, the airframe may be stopped. Therefore, even if the vehicle speed sensor 24 detects zero vehicle speed, the automatic plow control function is not immediately disabled.

  Further, as shown in the flowchart of FIG. 7, the automatic clearance control function indicates that the sub-transmission device (not shown) in the mission case 15 is in the road travel position (sub-transmission “on-road”). When the sensor 42 detects, or when the travel mode changeover switch 39 for 4WD / 2WD switching is at the road travel position as shown in the flowchart of FIG.

  At this time, it is desirable to sound the buzzer 26 to alert the operator. Further, it is further safer to display warning contents on the liquid crystal display unit 27 provided in the control unit, for example, “Please lift and lower the working machine with the position lever 30”.

  By prohibiting this function when traveling on the road in this way, even if the “lowering” of the work implement lifting switch 23 is mistakenly pressed, the work implement will not be lowered at a stretch, and stable travel is possible.

When the travel mode changeover switch 39 is set to the travel position, it is normally a two-wheel drive, and the tractor of this embodiment automatically becomes a four-wheel drive when entering a muddy, traveling steep hill or uneven road. There is. In addition, when the brake is applied, it automatically becomes a four-wheel drive. That is, the stop distance is shortened. Further, when the vehicle stops during operation, the vehicle enters a four-wheel drive state.
In this case, if the auxiliary speed change lever (not shown) is in the road position, the automatic plow control function is stopped regardless of whether the aircraft is stopped. Since the penetration control function may be stopped, at this time, even if the vehicle speed sensor 24 detects the vehicle speed as zero, the automatic penetration control function does not stop.

  Further, as shown in the flow chart of FIG. 9, the automatic plow control function indicates that when the forward / reverse switch 43 is in a position other than the forward side, for example, when it is in the reverse side, or the clutch pedal 44 is turned off. When the clutch pedal sensor 51 detects, it does not function.

When the vehicle speed sensor 24 detects the vehicle speed, but the vehicle speed is a very low speed below the predetermined vehicle speed (which is different depending on the model, the lowest speed that can be produced by the aircraft, or a speed close to the lowest speed) (this case is described in this specification). However, there is a case where an operator who intends to start work using the plow 12 at such a low speed cannot be used even if he / she wants to use the automatic plow control function while maneuvering. . In order to prevent such a situation, when the forward / reverse switch 43 is in the forward side or when the clutch pedal 44 is connected, it is determined that the tractor is running, so that the main speed can be changed even at a low speed. The function can be used and at the same time, it does not function when it is not necessary. Therefore, even if it is operated incorrectly, the work machine will not suddenly descend and break the work machine or asphalt.
Note that this function is prohibited when the forward / reverse lever 37 is not on the forward side or when the forward / backward switch 43 is not on the forward side. At this time, it is desirable to sound the buzzer 26 to alert the operator.

In the flowchart shown in FIG. 3, this control function can be used for the first time at a predetermined vehicle speed or higher. However, as shown in the flowchart of FIG. 10, when the vehicle is traveling at high speed (depending on the model, the maximum speed or maximum When the vehicle speed sensor 24 detects that the speed is close to the speed, a control configuration for prohibiting this function is provided. This is because, for example, there is an operator who performs a plow operation even when the road speed is high, such as when the farm scene is somewhat soft, so that even if the sub-shift is a high-speed position on the road, it is acceptable if the main shift is low.
In this case, even if the work implement lifting / lowering switch 23 is accidentally pushed to the lower side during high speed running, the work implement will not be lowered at a stretch, and stable high speed running is possible.

  When automatic plowing work (plowing work at a depth of 5 to 15 cm) is performed using a rotary (not shown) instead of the plow 12 as a working machine, the automatic plowing performed when the plow 12 is used. Control function is prohibited. When the rotary is mounted, the rotary cover sensor 45 attached to the base of the rotary cover operates, so that automatic plowing work is possible according to the detected value of the sensor 45, but at the same time the rotary cover sensor 45 (FIG. 2) Detects that the rotary is mounted, so that the automatic plow control function performed when the plow 12 is used can be prohibited.

  In this way, during automatic plowing work using the rotary, the function of lowering the lift arm 19 at the maximum flow rate of the hydraulic oil is prohibited, thereby preventing the work machine, asphalt, etc. from being damaged due to erroneous operation.

  In addition, if a switch 46 is provided that can be used to select whether or not the automatic scavenging control function is performed when using the plow 12, depending on the operator's preference or whether or not the automatic scavenging control function is executed as necessary. Can be selected.

  This switch 46 enables or disables the automatic scavenging control function that outputs the lift arm 19 to the lower side at the maximum flow rate of the hydraulic oil in the lift cylinder 17 when the work machine elevating switch 23 is continuously pressed to the lower side. The switch 23 can be selected and used if it is not desired to operate it carelessly or if it is desired.

  The control according to the flowchart shown in FIG. 11 is for lowering the lift arm 19 so that the work implement can be gradually lowered until the specified time elapses when the work implement lift switch 23 is continuously pushed downward. The oil amount is gradually increased to lower the lift arm 19, and the maximum flow rate can be gradually increased in a specified time instead of the maximum flow rate at once.

  Even if the work implement lifting / lowering switch 23 is continuously lowered, even if the work implement lifting / lowering switch 23 is pushed downward, the work implement lifting / lowering switch 23 is not lowered quickly but gradually becomes faster. In addition, since the operator notices an erroneous operation and can stop the operation, the work machine is not lowered at a stroke and damaged, or the asphalt of the paved road is not damaged.

7 Load sensor 10 Tractor body 12 Work machine (plow) 16 Cylinder case 17 Lift cylinder 18 Lift control valve 19 Lift arm 19a Lift arm shaft 21 Top link bracket 22 Draft sensing arm 23 Work machine lift switch 24 Vehicle speed sensor 26 Buzzer 27 Liquid crystal display Section 30 Position lever 31 Bracket 32 Lift arm raising solenoid 33 Lift arm lowering solenoid 37 Forward / reverse lever 38 Forward / reverse lever sensor 39 Travel mode switching switch 40 Draft lever 41 Bracket 42 Sub-shift "on-road" sensor 43 Forward / reverse switch 49 Lift arm sensor 50 Control device 51 Clutch pedal sensor 53 Draft ratio adjustment dial

Claims (5)

A hydraulic lift cylinder (17) for raising and lowering the work machine (12) attached to the rear part of the tractor body (10), and a lift arm raising solenoid (32) for sending hydraulic oil for operating the lift cylinder (17) to the ascending side ), A lift arm lowering solenoid (33) for sending hydraulic oil for operating the lift cylinder (17) to the lowering side, a lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), and a working machine for raising and lowering the working machine Lift switch (23), lift arm sensor (49) for detecting the lifting / lowering of the lift arm (19), load sensor (7) for performing draft control of the work implement, and vehicle speed sensor for detecting the vehicle speed of the tractor body (10) (24), a forward / reverse lever (37) or a forward / reverse switch (43) for controlling forward / backward movement of the tractor body (10), a forward / reverse lever (3 Reverse lever sensor before detecting the operating position of the) (38), the traveling speed change device of the tractor body (10), in a tractor provided with a running mode change-over switch (39) for switching the traveling mode of the traveling speed change device,
An automatic plowing control function that outputs the lift arm (19) to the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side;
A tractor comprising a control device (50) having a control function for prohibiting the automatic scavenging control when the vehicle speed sensor (24) detects substantially zero vehicle speed. A hydraulic lift cylinder (17) for raising and lowering the work machine (12) attached to the rear part of the tractor body (10), and a lift arm raising solenoid (32) for sending hydraulic oil for operating the lift cylinder (17) to the ascending side ), A lift arm lowering solenoid (33) for sending hydraulic oil for operating the lift cylinder (17) to the lowering side, a lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), a work implement lifting switch (23), a lift A lift arm sensor (49) for detecting the elevation of the arm (19), a load sensor (7) for draft control of the work implement, a vehicle speed sensor (24) for detecting the vehicle speed of the tractor body (10), a tractor body ( 10) Detects the operation position of the forward / reverse lever (37), the forward / reverse switch (43), or the forward / reverse lever (37) that controls the forward / backward movement That the forward-reverse lever sensor (38), the traveling speed change device of the tractor body (10), in a tractor provided with a running mode change-over switch for switching the (39) traveling mode of the traveling speed change device,
An automatic plowing control function that outputs the lift arm (19) to the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side;
When the forward / reverse lever sensor 37 detects that the operation position of the forward / reverse lever 37 is not on the forward side or the forward / backward switch 43 is not on the forward side, the automatic scavenging control is performed. The tractor provided with the control apparatus (50) which has a control function which prohibits. A hydraulic lift cylinder (17) for raising and lowering the work machine (12) attached to the rear part of the tractor body (10), and a lift arm raising solenoid (32) for sending hydraulic oil for operating the lift cylinder (17) to the ascending side ), A lift arm lowering solenoid (33) for sending hydraulic oil for operating the lift cylinder (17) to the lowering side, a lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), a work implement lifting switch (23), a lift A lift arm sensor (49) for detecting the elevation of the arm (19), a load sensor (7) for draft control of the work implement, a vehicle speed sensor (24) for detecting the vehicle speed of the tractor body (10), a tractor body ( 10) Detects the operation position of the forward / reverse lever (37), the forward / reverse switch (43), or the forward / reverse lever (37) that controls the forward / backward movement That the forward-reverse lever sensor (38), the traveling speed change device of the tractor body (10), in a tractor provided with a running mode change-over switch for switching the (39) traveling mode of the traveling speed change device,
An automatic plowing control function that outputs the lift arm (19) to the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side;
A tractor comprising a control device (50) having a control function for prohibiting the automatic plowing control except when the work implement is lowered below a predetermined height by detection by a lift arm sensor (49). . A hydraulic lift cylinder (17) for raising and lowering the work machine (12) attached to the rear part of the tractor body (10), and a lift arm raising solenoid (32) for sending hydraulic oil for operating the lift cylinder (17) to the ascending side ), A lift arm lowering solenoid (33) for sending hydraulic oil for operating the lift cylinder (17) to the lowering side, a lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), a work implement lifting switch (23), a lift A lift arm sensor (49) for detecting the elevation of the arm (19), a load sensor (7) for draft control of the work implement, a vehicle speed sensor (24) for detecting the vehicle speed of the tractor body (10), a tractor body ( 10) Detects the operation position of the forward / reverse lever (37), the forward / reverse switch (43), or the forward / reverse lever (37) that controls the forward / backward movement That the forward-reverse lever sensor (38), the traveling speed change device of the tractor body (10), in a tractor provided with a running mode change-over switch for switching the (39) traveling mode of the traveling speed change device,
An automatic plowing control function that outputs the lift arm (19) to the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side;
A tractor comprising a control device (50) having a control function for prohibiting the automatic plowing control when the load sensor (7) does not perform draft control of the work machine (12). A hydraulic lift cylinder (17) for raising and lowering the work machine (12) attached to the rear part of the tractor body (10), and a lift arm raising solenoid (32) for sending hydraulic oil for operating the lift cylinder (17) to the ascending side ), A lift arm lowering solenoid (33) for sending hydraulic oil for operating the lift cylinder (17) to the lowering side, a lift arm (19) that moves up and down by the expansion and contraction of the lift cylinder (17), a work implement lifting switch (23), a lift A lift arm sensor (49) for detecting the elevation of the arm (19), a load sensor (7) for draft control of the work implement, a vehicle speed sensor (24) for detecting the vehicle speed of the tractor body (10), a tractor body ( 10) Detects the operation position of the forward / reverse lever (37), the forward / reverse switch (43), or the forward / reverse lever (37) that controls the forward / backward movement That the forward-reverse lever sensor (38), the traveling speed change device of the tractor body (10), in a tractor provided with a running mode change-over switch for switching the (39) traveling mode of the traveling speed change device,
An automatic plowing control function that outputs the lift arm (19) to the lower side at a maximum flow rate of the hydraulic oil in the lift cylinder (17) when the work implement lift switch (23) is continuously pressed to the lower side;
When the sub-shift “on-road” sensor (42) detects the on-road travel position of the sub-transmission device or when the travel mode switch (39) is at the on-road travel position, the automatic shift control function is prohibited. A tractor comprising a control device (50).

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