JP7139274B2 - tractor - Google Patents

Description

The present invention mainly relates to a tractor to which a working machine can be attached.

Among work machines attached to tractors, there are known ones that can be switched between a stored state and a use state. Patent Document 1 discloses a plowing harrow, which is a work machine of this type.

The plowing harrow of Patent Document 1 includes a central working portion and side working portions arranged on both left and right sides of the central working portion. The side working part is configured to be foldable inward in the left-right direction.

Japanese Patent Application Laid-Open No. 2019-9600

Here, when using this type of storable work machine, the work machine is put into use (for example, the side work part of the harrow is spread out) and work is carried out in the field. After that, when returning home after finishing the work in the field, the working machine is put in the retracted state (for example, the side working part of the harrow is folded) and the vehicle travels outside the field. Therefore, if the operator forgets to put the work implement in the retracted state, the tractor may travel outside the field while the work implement is in use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its main object is to provide a tractor that cannot travel outside a field unless the working machine is in a retracted state.

Means and Effects for Solving Problems

The problems to be solved by the present invention are as described above. Next, the means for solving the problems and the effects thereof will be described.

According to the aspect of the present invention, a tractor having the following configuration is provided. This tractor includes a vehicle body, a communication section, a working machine lifting section, and a control device. The vehicle body can be mounted with a work machine that can change its state between a stored state and a use state. The communication unit receives from the work machine whether the work machine is in the stored state or the use state. The working machine elevating unit lifts and lowers the working machine between a raised position and a lowered position. The control device receives that the working machine is in the retracted state and permits traveling outside the field when the working machine is in the raised position.

In this way, the state of the work machine can be identified on the tractor side by receiving information from the work machine as to whether the work machine is in the used state or the stored state. As a result, it is possible to realize a configuration in which traveling outside the field is permitted only when the working machine is in the retracted state.

The tractor described above preferably has the following configuration. That is, this tractor is equipped with an auxiliary transmission capable of switching between at least the low speed side and the high speed side. When the control device receives that the work implement is in the retracted state and the work implement is in the raised position, the auxiliary transmission permits traveling on the high speed side.

As a result, since the high speed side of the sub-transmission is used when traveling outside the field, it is possible to more reliably prohibit traveling outside the field while the working machine is in use.

The tractor described above preferably has the following configuration. That is, this tractor is equipped with an auxiliary transmission capable of switching between at least the low speed side and the high speed side. The control device maintains the sub-transmission at the low speed side until it receives that the work implement has switched to the retracted state.

As a result, the sub-transmission is maintained on the low speed side, so that the operator can be reminded that he or she has forgotten to retract the work implement.

The tractor described above preferably has the following configuration. That is, the working machine is a harrow for puddling. The retracted state is a state in which a portion of the plowing section of the harrow is retracted. The use state is a state in which the tillage section stored in the storage state is usable.

As a result, it is possible to prevent the tractor from traveling outside the field while the plowing harrow is spread out.

The tractor described above preferably has the following configuration. That is, this tractor has a display section for displaying information about the working machine. If the control device does not receive from the work machine that the work machine has switched to the retracted state even after the elapsed time after detecting that the work machine is in the raised position is equal to or greater than a threshold value, Information relating to switching of the working machine from the use state to the storage state is displayed on the display unit.

This makes it possible for the operator to notice that he or she has forgotten to store the work implement.

The tractor described above preferably has the following configuration. That is, this tractor includes a sub-transmission device, a sub-transmission operating tool, and a display section. The auxiliary transmission is capable of switching between at least low speed and high speed. The sub-transmission operation tool can be operated to switch the sub-transmission. The display unit displays information about the working machine. The control device switches the work machine from the use state to the stored state when an instruction to switch to the high speed side is given by the auxiliary shift operation tool while the work machine is in the use state. is displayed on the display unit.

Thus, by notifying the operator of the reason why travel is prohibited, the operator can be urged to return the work implement to the retracted state.

BRIEF DESCRIPTION OF THE DRAWINGS The side view which shows the tractor and working machine which concern on one Embodiment of this invention. Power transmission diagram of the tractor. FIG. 2 is a rear view showing a storage state and a use state of the working machine; FIG. 2 is a block diagram showing a configuration for performing travel prohibition control; 4 is a flowchart showing travel prohibition control; FIG. 4 is a view showing work machine settings and warning messages displayed on the sub-display; 4 is a flowchart showing processing for adjusting the operation of the work machine based on information acquired from the work machine;

Next, embodiments of the invention will be described with reference to the drawings. FIG. 1 is a side view showing a tractor 10 and a work implement 3 according to one embodiment of the present invention.

A tractor 10 shown in FIG. 1 is equipped with various working machines 3 such as a rotary, harrow, loader, plow, and box scraper on a vehicle body 11 as necessary, and the working machines 3 supported by the vehicle body 11 perform various works. It can be carried out. FIG. 1 shows an example in which a harrow for plowing is used as the working machine 3 . In the following description, the terms "left side", "right side", and the like simply refer to the left side and the right side in the direction in which the tractor 10 moves forward.

As shown in FIG. 1 , the tractor 10 includes a vehicle body 11 , a pair of left and right front wheels 12 , and a pair of left and right rear wheels 13 . A bonnet 14 is arranged in the front part of the vehicle body 11 , and an engine 15 is arranged inside the bonnet 14 .

A transmission case 16 is arranged between the pair of left and right rear wheels 13 . The output of the engine 15 is changed in speed by a hydraulic transmission 120 or the like arranged in the transmission case 16 and transmitted to the front wheels 12 and the rear wheels 13 .

A pair of left and right lower links 18 and one top link 19 are arranged at the rear of the transmission case 16 . Furthermore, a PTO shaft 20 is arranged so as to protrude from the rear portion of the transmission case 16 . The work implement 3 is connected to the lower link 18 and the top link 19 and driven by the PTO shaft 20 .

A work implement lifting mechanism 25 , a work implement angle changing mechanism 26 , and a connecting member 28 are provided at the rear portion of the vehicle body 11 .

The working machine lifting mechanism 25 includes a pair of left and right lift arms 21 and a lift cylinder (working machine lifting section) 22 configured as a hydraulic cylinder. The tip of one of the left and right lift arms 21 is connected to one lower link 18 via a link member 23, and the tip of the other lift arm 21 is connected to the other lower link 18 via a rolling cylinder 24, which will be described later. Concatenated. With this configuration, the height at which the work implement 3 is supported by the vehicle body 11 can be changed by driving the lift cylinder 22 .

The work implement angle changing mechanism 26 includes a rolling cylinder 24 configured as a hydraulic cylinder. The rolling cylinder 24 is arranged to connect the right lift arm 21 and the right lower link 18 of the left and right pair. With this configuration, by driving the rolling cylinder 24 , it is possible to change the lateral tilt posture in which the work implement 3 is supported with respect to the vehicle body 11 .

The connecting member 28 is a member for connecting the lower link 18 and the top link 19 to the work implement 3 .

Above the mission case 16 and behind the bonnet 14, a cabin 31 for an operator to board is arranged. Inside the cabin 31, a meter panel 36 capable of displaying the travel speed, the engine speed, the state of the working machine, the warning light, and the like is provided. Note that these pieces of information may be displayed on a sub-display (display unit) 37 arranged in the cabin 31 .

A driver's seat 32 is provided inside the cabin 31 , and various operating tools are provided near the driver's seat 32 . Specifically, in the vicinity of the driver's seat 32, a steering handle 33, a sub-transmission lever (sub-transmission operating tool) 34, and a reverser lever 35 are arranged.

The steering handle 33 is an operating tool for the operator to steer. The auxiliary shift lever 34 is an operation tool for instructing, for example, one of two stages (low speed side and high speed side). After specifying a rough speed with the sub-transmission lever 34, the operator specifies a fine speed using the main transmission lever (not shown). Note that the sub-transmission may be switchable in three or more stages. In this case, the three or more sub-transmission stages are preferably divided into either a transmission stage (low-speed side) for field work or a transmission stage (high-speed side) for traveling on roads (outside the field). (For example, in the case of 3 stages, 1 low speed, 1 high speed, and 2 high speeds, etc.). The reverser lever 35 is an operating tool for instructing, for example, forward, reverse, and neutral. When the forward direction is instructed, the power of the engine 15 is transmitted so as to move the tractor 10 forward. When reverse is instructed, the power of the engine 15 is transmitted so as to reverse the tractor 10 . When neutral is commanded, engine power is not transmitted to the drive wheels.

A hydraulic transmission (HST) 120 is accommodated in the mission case 16 for appropriately shifting the power transmitted from the engine 15 . The power of the engine 15 is transmitted to the main transmission input shaft 121 of the transmission case 16 via the output shaft of the engine 15 shown in FIG. It is designed to be transmitted to the rear wheels 13 .

Hydraulic transmission 120 comprises a hydraulic pump 124 and a hydraulic motor 126 interconnected by a hydraulic pipe. The hydraulic pump 124 is driven by the main transmission input shaft 121 while the hydraulic motor 126 drives the first auxiliary transmission shaft 131 .

One of the hydraulic pump 124 and the hydraulic motor 126 is of fixed displacement type, and the other is of variable displacement type. In this embodiment, the hydraulic motor 126 is of a fixed displacement type, and the hydraulic pump 124 is of a variable displacement type, so that the amount of oil (discharge amount) discharged by the hydraulic pump 124 can be changed. Note that the hydraulic motor 126 may be of a variable displacement type, and the hydraulic pump 124 may be of a fixed displacement type.

The hydraulic pump 124 is provided with a movable swash plate 125 that changes the discharge amount according to the inclination angle. The inclination angle of the movable swash plate 125 changes when the operator performs a gear shift operation related to the main gear shift. Thereby, the rotation speed of the first sub-transmission shaft 131 can be changed.

The main transmission input shaft 121 is rotated by the power of the engine 15 . A first main transmission shaft 122 is connected to the main transmission input shaft 121 , and the first main transmission shaft 122 is configured to rotate integrally with the main transmission input shaft 121 .

A PTO clutch 128 is connected to the first main transmission shaft 122 for switching between transmission and cutoff of power to the PTO shaft 20 . The power of the engine 15 transmitted to the first main transmission shaft 122 is transmitted to the second main transmission shaft 123 via the PTO clutch 128 . The power of the engine 15 transmitted to the second main transmission shaft 123 is output to the PTO shaft 20 after being shifted and transmitted via the PTO gear group 129 . With this configuration, power can be transmitted to the working machine 3 attached to the tractor 10 to drive the working machine 3 .

A first auxiliary transmission shaft 131 and a front wheel transmission shaft 133 are further arranged near the hydraulic transmission 120 . The first sub-transmission shaft 131 is arranged to protrude from the hydraulic motor 126 , and the rotation steplessly changed by the hydraulic transmission 120 is output to the first sub-transmission shaft 131 .

A sub-transmission device 130 is connected to the first sub-transmission shaft 131 . The subtransmission device 130 is configured to change the speed of rotation of the first subtransmission shaft 131 and transmit it to the second subtransmission shaft 132 . The rotation of the second sub-transmission shaft 132 is input to the rear wheel differential device 136, and drives the rear wheels 13 via the axle, transmission gear, etc. in the rear axle case.

Also, the rotation of the second auxiliary transmission shaft 132 is transmitted to the front wheel transmission shaft 133 . The rotation of the front wheel transmission shaft 133 is input to the front wheel differential device 135, and drives the front wheels 12 via the axle, transmission gear, etc. in the front axle case.

The working machine 3 is a harrow for puddling. Plowing is the work of crushing the soil and flattening the surface of the paddy field after filling it with water.

As shown in FIG. 1 , the working machine 3 includes a connecting portion 71 for connecting the working machine 3 to a connecting member 28 provided at the rear portion of the vehicle body 11 . The connecting portion 71 may be configured to be directly connected to the lower link 18 and the top link 19 without the connecting member 28 interposed therebetween.

A tillage cover 72 is provided behind the connecting member 28 . A tillage rotary shaft 73 is rotatably attached to the tillage cover 72 . The tillage rotary shaft 73 rotates about the lateral direction as a rotary shaft by power transmitted from the PTO shaft 20 by a power transmission mechanism (not shown). A plurality of tillage tines 74 are connected to the tillage rotation shaft 73 so as to be arranged side by side. With this configuration, the tillage tines 74 rotate together with the tillage rotary shaft 73, so that the soil of the rice field can be crushed.

A leveling plate 75 is arranged behind the tillage cover 72 . The leveling plate 75 is attached to the tillage cover 72 so as to be rotatable about the left-right direction as a rotation axis. Further, the leveling plate 75 is biased downward by a biasing member (not shown). With this configuration, the field surface can be flattened. An extended ground leveling plate 76 for widening the ground leveling width is provided outside the leveling board 75 in the left-right direction.

In addition, as shown in FIG. 3, the work machine 3 is configured to be openable and closable. Specifically, the working machine 3 has a three-part structure, and includes a central plowing section 3a and left and right side plowing sections 3b. A tillage cover 72, a tillage rotary shaft 73, a tillage claw 74, and a leveling plate 75 are provided in each of the central tillage section 3a and the side tillage section 3b. The side plowing section 3b is rotatably connected to the central plowing section 3a via a rotation shaft member (not shown). The central tillage section 3a and the side tillage section 3b are connected by an opening/closing cylinder 77. As shown in FIG. By extending and contracting the open/close cylinder 77, the working machine 3 can be switched between a stored state (upper side in FIG. 3) and a use state (lower side in FIG. 3). The storage state is a state in which the two side tillage units 3b are positioned above the central tillage unit 3a, that is, the two side tillage units 3b are folded and stored. The use state is a state in which the two side plowing sections 3b are positioned laterally outside the central plowing section 3a to widen the working width. In the use state, after the lift cylinder 22 is operated to lower the work implement 3 (at the position of the two-dot chain line on the lower side of FIG. 3), the work by the work implement 3 is performed on the field.

As shown in FIG. 3 , the working machine 3 is provided with a state detection sensor 81 and a leveling plate rotation angle sensor 82 .

The state detection sensor 81 is a sensor that detects whether the working machine 3 is in the retracted state or in the used state (in other words, whether the side plowing section 3b is extended). The state detection sensor 81 is a limit switch, and is configured to be energized by coming into contact with any portion when the side plowing section 3b is in the retracted state. Since the state detection sensors 81 are arranged as a pair on the left and right, they can individually detect the states of both the left and right side plowing sections 3b.

The leveling plate rotation angle sensor 82 detects the rotation angle of the leveling plate 75 (in other words, how much the leveling plate 75 moves up and down during leveling). The ground plate rotation angle sensor 82 is, for example, a potentiometer that detects the rotation angle of the ground plate 75 or a link attached to its rotation shaft. Based on the detection result of the ground leveling plate rotation angle sensor 82, for example, the degree of the size of the soil mass in the field after tillage can be detected. That is, when the soil mass remaining after tilling is large, the leveling plate rotation angle sensor 82 is largely rotated up and down. On the other hand, when the soil mass remaining after tilling is small, the leveling plate rotation angle sensor 82 rotates up and down slightly. Therefore, based on the magnitude and frequency of rotation of the ground leveling plate rotation angle sensor 82, it is possible to obtain information about the size of the soil mass remaining in the field after tillage.

The structures of the two sensors described above are examples, and other structures may be used. For example, the state detection sensor 81 may be configured to detect the rotation angle of the rotation shaft of the side plowing section 3b, or may be configured to detect the expansion/contraction length of the open/close cylinder 77 .

Next, with reference to FIG. 3, an electrical configuration for performing travel prohibition control will be described. As shown in FIG. 3 , the tractor 10 has a control device 50 for controlling the work implement 3 . The control device 50 controls the operation, height, attitude, etc. of the working machine 3 . The control device 50 includes an arithmetic device such as a CPU, and a storage device such as a ROM and a RAM. By cooperating with these hardware and the control program stored in the storage device, the control device 50 can be used as a communication unit 51, a travel control unit 52, a work control unit 53, a display control unit 54, and the like. can function.

A detection value of the work implement height sensor 41 is input to the control device 50 . The work implement height sensor 41 is a sensor that detects the height of the work implement 3, for example, a sensor that detects the position of the cylinder rod of the lift cylinder 22 (the length of the lift cylinder 22).

The communication unit 51 performs processing for communicating with the work machine side control device 80 provided in the work machine 3 . The communication unit 51 may be configured to perform wired communication, or may be configured to perform wireless communication. Thereby, the control device 50 can receive information from the work implement side control device 80 . The information received by the control device 50 includes, for example, the type of the work machine 3 (rotary, halo, etc.), special functions of the work machine 3 (for example, whether or not there is a storage function), detection values of the state detection sensor 81, A value detected by the ground plate rotation angle sensor 82 and the like. For example, instead of transmitting the detection value of the state detection sensor 81 to the control device 50 as it is, the work machine side control device 80 determines whether the work machine 3 is in the storage state or the use state, and transmits the determination result to the control device 50. You may

The travel control unit 52 controls travel of the tractor 10 . The travel control unit 52 performs control to prohibit travel of the tractor 10 under certain conditions, for example. The travel control unit 52 prohibits travel of the tractor 10 by, for example, operating an actuator (not shown) to place the movable swash plate 125 in neutral (a state in which power is not transmitted). Alternatively, the travel control unit 52 may prohibit travel of the tractor 10 by activating the brake, or disengage the clutch so that power is not transmitted from the engine 15 to the front wheels 12 and the rear wheels 13. Traveling of the tractor 10 may be prohibited.

The travel control unit 52 can also perform control to change the vehicle speed autonomously or according to an operator's instruction. The travel control unit 52 changes the vehicle speed of the tractor 10 by changing the rotation angle of the movable swash plate 125, for example.

The work control unit 53 controls an electromagnetic valve arranged between the lift cylinder 22 and the hydraulic pump to change the height at which the work implement 3 is supported by the vehicle body 11 (work implement height). I do. Further, the height of the working machine is divided into a lowered position, which is the height when working on a field, and a raised position, which is higher than the lowered position and mainly the height of the working machine 3 when traveling. be able to. The work control unit 53 also controls the electromagnetic valve arranged between the rolling cylinder 24 and the hydraulic pump to change the lateral tilt posture of the work implement 3 .

The display control unit 54 performs control for displaying, for example, information about the work machine 3 on the sub-display 37 or the like.

Next, the travel prohibition control for prohibiting the tractor 10 from traveling outside the field when the working machine 3 is in use will be described with reference to the flowchart of FIG. 5 .

First, the communication unit 51 of the control device 50 communicates with the work machine side control device 80 immediately after the work machine 3 is mounted, for example, and confirms that the work machine 3 is a halo for puddling (type of work machine). It is received that the working machine 3 has a storage function (whether or not there is a storage function) (S101).

Next, the communication unit 51 of the control device 50 acquires the open/close state of the work implement 3 from the work implement control device 80 (S102). The open/closed state indicates whether the working machine 3 is in the retracted state or in the used state, in other words, whether the side plowing section 3b is retracted. The information acquired by the control device 50 is the detection value of the state detection sensor 81 or information obtained from the detection value. Next, based on the information acquired in step S102, the control device 50 determines whether or not the work implement 3 is in the retracted state (S103).

When the work implement 3 is not in the retracted state (that is, when it is in use), the travel control unit 52 of the control device 50 prohibits travel in the high speed side of the sub-shift as described below. Further, the control device 50 determines whether or not the work implement height is at the raised position based on the work implement height sensor 41 (S104), and the work implement height is not at the raised position (that is, is at the lowered position). ), the vehicle is prohibited from running on the high speed side of the sub-shift.

Specifically, the control device 50 determines whether or not the sub-shift is on the high speed side based on the detection result of the sensor or the like that detects the position of the sub-shift lever 34 (S105). Then, when it is determined that the secondary shift is on the high speed side, the travel control unit 52 performs travel prohibition processing (S106). The travel prohibition process is, as described above, a process for disabling the tractor 10 from traveling by, for example, setting the movable swash plate 125 to neutral. Note that the travel prohibition process is continuously performed as long as the sub-shift is on the high speed side. Further, when the sub-shift is on the low speed side, the travel prohibition process is not performed. It should be noted that a condition that the reverser lever is in the forward position may be added to the determination in step S105.

Further, when the travel prohibition process is performed, the display control unit 54 of the control device 50 generates a warning sound and displays a warning message 96 on the sub-display 37 as shown in FIG. 6 (S108). FIG. 6 shows an example in which a warning message 96 is displayed on the screen displaying information about the working machine. In FIG. 6, a display 91 indicating a tractor and a work machine, an inclination meter 92, and a reference setting button 93 are displayed.

The tilt meter 92 indicates whether the work implement 3 is tilted left or right. For example, when it is determined that the work implement 3 is tilting to the left based on the detection result of the tilt sensor (not shown) provided on the tractor 10 or the work implement 3, the bar of the tilt meter 92 moves to the left. . Further, by operating the reference setting button 93, the inclination meter 92 is adjusted so that the inclination of the work implement 3 at the time of the operation is displayed as the reference state (horizontal state). A depth meter 94 and a reference setting button 95 are displayed on the sub-display 37 not only for the lateral tilt of the working machine 3 but also for the depth direction.

Note that when another screen is displayed on the sub-display 37, the display control unit 54 may display the warning message 96 on that screen. Further, the display control unit 54 may display the warning message 96 on the meter panel 36 instead of or in addition to the sub-display 37 .

By displaying the warning message 96 at the timing when the travel prohibition process is performed in this way, the operator can notice that the work implement 3 is in use. Also, even if the sub-transmission is on the low speed side, the warning message 96 is similarly displayed when the elapsed time after the work implement height reaches the raised position is equal to or greater than the threshold value (S107). This is to prompt the operator to return the work implement 3 to the retracted state because it is difficult to assume that work will be performed when the work implement 3 is raised to the raised position.

By performing the above processing, the tractor 10 cannot travel outside the farm field with the side plowing portion 3b of the working machine 3 spread out. Also, by displaying the warning message 96, the operator can notice that the work implement 3 has been forgotten to be stored.

Even after the travel prohibition process is performed, the control device 50 repeats the process of FIG. Then, when the work implement is in the retracted state and the height of the work implement is at the raised position, traveling with the sub-transmission on the high speed side is permitted (S109). In this case, even if the sub-shift is switched to the high speed side, the travel prohibition process is not performed. This allows the tractor 10 to travel outside the field.

Next, processing for adjusting the operation of the work machine 3 based on the information acquired from the work machine 3 will be described with reference to the flowchart of FIG. 7 .

First, the communication unit 51 of the control device 50 acquires a change in the rotation angle of the leveling plate 75 from the working machine side control device 80 (S201). As described above, based on the magnitude and frequency of change in the rotation angle of the ground leveling plate 75, it is possible to obtain information about the size of the lump of soil remaining in the field after tillage.

Next, based on the information acquired in step S201, the control device 50 estimates the size of the soil mass in the field after tillage (S202). As described above, the larger the size of the soil mass, the greater the change in the rotation angle of the leveling plate 75 . If the rotation angle of the ground leveling plate 75 includes a large angle and a small angle, the average value of the size of the soil mass is estimated by, for example, calculating the average value.

The control device 50 determines whether or not the size of the lump of earth calculated in step S202 is equal to or larger than the threshold value (S203). For example, the threshold is set to a predetermined initial value at the time of shipment from the factory, and the operator can change the magnitude of the threshold as necessary.

If the size of the soil mass is equal to or larger than the threshold, there is a possibility that the plowing by the plowing tines 74 is insufficient. At least one of reducing the vehicle speed is performed (S204). Methods of increasing the PTO rotation speed include, for example, a method of changing the speed of a device that shifts the PTO, and a method of increasing the engine rotation speed. By increasing the PTO rotation speed, the rotation speed of the tillage tines 74 is increased, so that more fine tillage work can be performed. In addition, even when the vehicle speed is reduced, the number of times the tillage tines 74 act per unit area increases, so the tillage work can be performed more finely.

Further, for example, when the difference between the size of the clod and the threshold value is equal to or greater than a predetermined value, the control device 50 both increases the PTO rotation speed and decreases the vehicle speed to bring the size of the clod closer to the threshold early and reliably. processing may be performed.

If the size of the soil mass is less than the threshold, there is a possibility that the plowing tines 74 are excessively plowed. at least one of the rises of (S205). The effects of PTO rotation speed and vehicle speed on tillage are as described above.

The control device 50 continuously performs the processing shown in FIG. That is, for example, when the PTO rotation speed is increased and the size of the soil mass falls below the threshold value, the PTO rotation speed is decreased. As a result, the size of the clod can always be brought close to the threshold value.

In this embodiment, there is one threshold for the size of the lump of earth, but two thresholds, an upper limit threshold and a lower limit threshold, may be set. That is, when the size of the soil mass is equal to or larger than the lower limit threshold value and equal to or smaller than the upper limit threshold value, the PTO rotation speed and the vehicle speed are maintained. Also, when the size of the lump of earth falls below the lower limit threshold, the PTO rotation speed is decreased or the vehicle speed is increased. In addition, when the size of the soil mass exceeds the upper limit threshold value, the PTO rotation speed is increased or the vehicle speed is decreased. This makes it difficult for the PTO rotational speed and vehicle speed to be changed frequently.

As described above, the tractor 10 of this embodiment includes the vehicle body 11, the communication unit 51, the lift cylinder 22, and the control device 50. The vehicle body 11 can be attached with the work machine 3 that can change its state between a stored state and a use state. The communication unit 51 receives from the work machine 3 whether the work machine 3 is in the stored state or the use state. The lift cylinder 22 raises and lowers the working machine 3 between the raised position and the lowered position. When the control device 50 receives that the work implement 3 is in the retracted state and the work implement 3 is in the raised position, it permits traveling outside the field.

In this way, the state of the work implement 3 can be identified on the tractor 10 side by receiving information from the work implement 3 as to whether the work implement 3 is in the used state or the stored state. As a result, it is possible to realize a configuration in which traveling outside the field is permitted only when the work implement 3 is in the retracted state.

In addition, the tractor 10 of the present embodiment is equipped with an auxiliary transmission 130 capable of switching between at least the low speed side and the high speed side. When the control device 50 receives that the work implement 3 is in the retracted state and the work implement 3 is in the raised position, the sub-transmission permits traveling at the high speed side.

As a result, the high speed side of the sub-transmission is used when traveling outside the agricultural field, so traveling outside the agricultural field can be prohibited more reliably.

Alternatively, the control device 50 of the tractor 10 may be configured to maintain the sub-transmission at the low speed side until it receives that the work implement 3 has switched to the retracted state.

Specifically, by providing a structure or the like capable of regulating the movement of the sub-transmission lever 34, it is possible to realize a configuration in which the sub-transmission lever 34 cannot move to the high speed side (maintained on the low speed side). Alternatively, by adopting a structure in which the instruction to switch to the sub-shift is electrically transmitted, it is possible to prevent the sub-shift from being switched even if the operator performs an operation to set the sub-shift to the high speed side. .

As a result, the sub-transmission is maintained on the low speed side, so that the operator can be reminded that the work implement 3 has been forgotten to be retracted.

Further, in the tractor 10 of the present embodiment, the working machine 3 is a harrow for puddling. The retracted state is a state in which part of the plowing section of the harrow (side plowing section 3b) is retracted. The use state is a state in which the plowing section (side plowing section 3b) stored in the stored state can be used.

As a result, it is possible to prevent the tractor from traveling outside the field while the plowing harrow is spread out.

The tractor 10 of this embodiment also includes a sub-display 37 that displays information about the work implement 3 . If the control device 50 does not receive from the work machine that the work machine 3 has switched to the retracted state even if the elapsed time after detecting that the work machine 3 is in the raised position is equal to or greater than the threshold value, the control device 50 3 is displayed on the sub-display 37 regarding switching from the use state to the storage state.

This makes it possible for the operator to notice that he has forgotten to store the work implement 3 .

Further, in the tractor 10 of the present embodiment, when the work implement 3 is in use and an instruction to switch to the high-speed side is given by the auxiliary transmission lever 34, the control device 50 changes from the use state of the work implement 3 to the high speed side. Information about switching to the storage state is displayed on the sub-display 37 .

Thus, by informing the operator of the reason why travel is prohibited, the operator can be urged to return the work implement 3 to the retracted state.

Although the preferred embodiments of the present invention have been described above, the above configuration can be modified, for example, as follows.

In the above embodiment, in addition to displaying the warning message 96, the traveling of the tractor 10 is physically prohibited by, for example, setting the movable swash plate 125 to neutral. Alternatively, the operator may be prohibited from driving the tractor 10 by only displaying the warning message 96, for example.

The flowcharts shown in the above embodiments are examples, and some of the processes may be omitted, the contents of some of the processes may be changed, or new processes may be added. For example, the process of step S107 in FIG. 5 may be omitted. Also, in the above embodiment, the warning message 96 is displayed after the secondary shift shifts to the high speed side (S105), but instead of this, after the conditions of steps S103 and S104 have been satisfied, traveling outside the field is prohibited. A message may be displayed to indicate that the secondary gear is set to the high speed side.

The warning message 96 in the above embodiment is an example, and different contents may be displayed. For example, it may be further displayed that the vehicle cannot travel outside the field, that the sub-transmission cannot be set to the high speed side, or the like.

In the above-described embodiment, an example of using a harrow for plowing as the working machine 3 has been described. The present invention can also be applied to the working machine.

3 work machine 10 tractor 22 lift cylinder (work machine lifting section)
37 sub-display (display)
50 control device 51 communication unit 52 travel control unit 53 work control unit 80 work machine side control device 81 state detection sensor 82 ground plate rotation angle sensor

Claims (6)

In a tractor working in a field,
a vehicle body to which a work machine capable of changing its state between a stored state and a use state can be attached;
a communication unit that receives from the work machine whether the work machine is in the stored state or the use state;
a working machine elevating unit that raises and lowers the working machine between a raised position and a lowered position;
a control device that receives that the working machine is in the retracted state and permits traveling outside a field when the working machine is in the raised position;
A tractor comprising: A tractor according to claim 1,
Equipped with an auxiliary transmission capable of switching between at least the low speed side and the high speed side,
The control device is characterized in that, when receiving that the work implement is in the retracted state and the work implement is in the raised position, the sub-transmission permits traveling on the high speed side. tractor. A tractor according to claim 1,
Equipped with an auxiliary transmission capable of switching between at least the low speed side and the high speed side,
The tractor, wherein the control device maintains the sub-transmission at the low speed side until receiving that the working machine has switched to the retracted state. A tractor according to any one of claims 1 to 3,
The working machine is a plowing harrow,
The stored state is a state in which a part of the plowing section of the harrow is stored,
The tractor is characterized in that the use state is a state in which the plowing section stored in the retracted state can be used. A tractor according to any one of claims 1 to 4,
A display unit that displays information about the work machine,
If the control device does not receive from the work machine that the work machine has switched to the retracted state even after the elapsed time after detecting that the work machine is in the raised position is equal to or greater than a threshold value, A tractor, wherein information relating to switching of the working machine from the use state to the storage state is displayed on the display unit. A tractor according to claim 1,
an auxiliary transmission capable of switching between at least low speed and high speed;
A sub-transmission operation tool capable of switching the sub-transmission;
a display unit that displays information about the work machine;
with
The control device switches the work machine from the use state to the stored state when an instruction to switch to the high speed side is given by the auxiliary shift operation tool while the work machine is in the use state. A tractor characterized by displaying information on the display unit.

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