JP4467515B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle.

Conventionally, for example, Patent Document 1 discloses a tractor. What is shown in Patent Document 1 is as follows.
The steering wheel operation amount is detected by the steering angle sensor 11 and transmitted to the control unit 10. The transmission includes a main transmission 1 and an auxiliary transmission 2. The main transmission 1 is a sink mesh gear type transmission that is configured to be capable of four-stage shifting. The switching control valve 3 and the switching control valve 4 are switched by the control unit 10, and the push-pull cylinders 57 and 58 are expanded and contracted. Shift. The sub-transmission 2 is constituted by a hydraulic transmission capable of four-speed transmission, and one of the proportional pressure control valves 5, 6, 7, and 8 is excited by the control unit 10 to generate a medium speed clutch CM and a high speed clutch CM. Any one of the low-speed clutch CL and the ultra-low-speed clutch CLL is connected.

The control unit 10 continues to detect the handle operation, and detects whether or not the cut angle is operated to be greater than the set angle a. When operated beyond the set angle a, the shift actuators 3 to 8 are energized to lower the shift position by one step from the current shift position. Further, it continues to detect the turning angle of the handle 26 and determines whether or not to detect a turning angle that is greater than the set angle b greater than the angle a. If YES, the one-speed shift position is set further than the shift position after the shift. Perform the lowering operation. When returning to straight running beyond the middle of the turn, the system waits for detection of a turning angle equal to or less than the set angle b, and if this is detected, the shift stage is raised and returned by one step. The system waits for the steering angle to return to a setting angle a or less, and if this is detected, the shift position is raised by one step after a predetermined time and returns to the original shift position.
In this way, the steering wheel turning angle is detected during turning, and the gearshift position is lowered stepwise in accordance with this angle to decelerate. It is fast.

JP-A-9-290662 (paragraphs [0011], [0012], [0017], [0018], FIGS. 1 and 7)

  For example, when working with a field cultivator, as shown in FIG. 3, when the work traveling at the work location A is finished, a turning travel is performed in which a U-turn is made at the headland B and then moved to the next work location C. In the turning end stage range Z before the end of the turning, the self-propelled vehicle body is changed to the work location C so that no plowing leaks between the work location C and the previous work location A when the next work location C is traveled. On the other hand, a steering operation for positioning is performed. For this reason, in the final turning range Z, it is easier to perform a suitable steering operation when traveling at a low speed than when traveling at a high speed, and the positioning of the self-propelled vehicle body with respect to the next work location C can be performed accurately and easily. Can do.

  If the above-mentioned conventional traveling control technology is adopted, if the vehicle is turning, the self-propelled vehicle body decelerates from the beginning of the turning and returns to the straight traveling, and before the completion of the turning, compared to the time of the working traveling. Steering operation can be performed while traveling at low speed. However, in the case of a cultivator, for example, it can travel at a relatively low speed during work and can turn without any problem even if it turns at the same traveling speed as during work travel. Even during the period until reaching the end of the range, it took time to make a turn because it decelerated.

  An object of the present invention is to provide a work vehicle that can quickly finish turning while being able to perform alignment before turning is finished accurately and easily.

In the work vehicle according to the first aspect of the present invention, there is provided traveling speed detecting means for detecting the traveling speed of the self-propelled vehicle body, and a turning angle sensor for detecting a turning angle from the straight traveling direction of the front wheel, the cutting angle sensor The turning angle measuring means for measuring the turning angle from the turning start point of the self-propelled vehicle body based on the detected turning angle by the traveling speed detection means and the traveling speed detected by the traveling speed detection means is provided, so Provide low speed setting means to set the speed,
When the measured turning angle by the turning angle measuring means becomes the set turning angle, based on the detection information by the running speed detecting means and the measurement information by the turning angle measuring means so that the self-running vehicle body runs at the set low speed. Is provided with control means for shifting the speed of the self-propelled vehicle body.

  When the self-propelled vehicle body is turned, the turning angle of the self-propelled vehicle body is measured by the turning angle measuring means. When this measured turning angle becomes the set turning angle, the control means detects information detected by the traveling speed detecting means and the turning angle measurement. The self-propelled vehicle body is shifted based on the measurement information by the means, and the self-propelled vehicle body travels at the set low speed set by the low-speed setting means. As a result, when the set turning angle and the set low speed are set to appropriate angles and speeds, the self-running vehicle body that has finished working travels when turning to move to the next work location. Until the vehicle reaches the end-of-turn range before the end of the turn, turn at a speed that is faster than the speed at which the end-of-turn range was reached, such as the same travel speed as during work, and enter the end-of-turn range. When the vehicle reaches the vehicle, the gear shift operation is automatically performed, and in the final turn range, the vehicle can turn at a set low speed at which the steering operation for aligning the self-propelled vehicle body with the work location can be easily performed.

  Therefore, according to the first aspect of the present invention, when turning to the next work location after finishing the work travel, the travel speed in the end turn range, such as the travel speed similar to the work travel, is reached until reaching the end turn range. Also, turn at a high traveling speed and quickly move to the next work location, and in the end of the turn range, steer while operating at low speed and align with the next work location accurately and easily, It is possible to efficiently perform work with good finish, such as difficulty in leaking work between work points.

In the second invention, in the configuration of the first invention,
The control means detects the traveling speed detected by the traveling speed detecting means when the measured turning angle by the turning angle measuring means becomes a set turning angle and the measured turning angle by the turning angle measuring means becomes a set turning angle. When the speed is higher than the set low speed, the self-propelled vehicle body is shifted so that the self-propelled vehicle body travels at the set low speed.

  When the traveling speed detected by the traveling speed detecting means is higher than the set low speed when the turning angle measured by the turning angle measuring means becomes the set turning angle, the running speed of the self-propelled vehicle body is changed. Because it is configured, the information processing for the shift control based only on the detected traveling speed when the turning angle measured by the turning angle measuring means becomes the set turning angle is performed. Shifting can be performed.

  Therefore, according to the second aspect of the invention, it is possible to simplify the information processing performed by the control means, and it can be advantageously obtained in terms of structure and cost.

In the third invention, in the configuration of the first or second invention,
An elapsed time measuring means for measuring the time elapsed since the self-propelled vehicle body started traveling at a low speed set by the low speed setting means;
When the elapsed time measured by the elapsed time measuring means reaches the set elapsed time, the elapsed time is adjusted so that the self-propelled vehicle shifts to a travel speed before the self-propelled vehicle shifts to the set low speed. Based on the measurement information obtained by the measuring means, the vehicle body is shifted so that the vehicle body travels.

  That is, if the set elapsed time is set appropriately, the self-propelled vehicle body reaches the end turning range and starts traveling at the set low speed, and the steering operation is performed while the self-propelled vehicle body is traveling at low speed to perform the next work. When this position alignment is completed, the measurement elapsed time by the elapsed time measurement means becomes the set elapsed time, and the control means performs the traveling shift of the self-propelled vehicle body based on the measurement information by the elapsed time measurement means, The self-propelled vehicle body travels by returning the traveling speed before traveling at the set low speed. As a result, when the turning travel is completed and the positioning for the next work location is completed, the self-propelled vehicle body automatically returns to the work travel speed and travels to the next work location at this work travel speed. Can be done.

  Therefore, according to the third aspect of the invention, the vehicle is driven at a set low speed so that the positioning can be easily performed in the final turning range, but when the positioning is completed, the traveling speed is automatically returned to the traveling speed before the low-speed traveling. It is possible to easily resume the operation on the operation surface.

In the fourth invention, in any one configuration of the first or second invention,
A self-propelled vehicle body is provided with a travel distance measuring means for measuring the travel distance traveled after the vehicle starts running at a low speed set by the low speed setting means;
When the travel distance measured by the travel distance measurement means becomes a set travel distance, the travel distance of the control means is such that the self-propelled vehicle shifts to a travel speed before shifting to the set low speed. Based on the measurement information obtained by the measuring means, the vehicle body is shifted so that the vehicle body travels.

  That is, if the set travel distance is set appropriately, the self-propelled vehicle body reaches the end turning range and starts traveling at the set low speed, and the next operation is performed by steering the self-propelled vehicle body while traveling at low speed. When the position is aligned and the positioning is completed, the measured travel distance by the travel distance measuring means becomes the set travel distance, and the control means performs the traveling shift of the self-propelled vehicle body based on the measurement information by the travel distance measuring means, The self-propelled vehicle body travels by returning the traveling speed before traveling at the set low speed. As a result, when the turning travel is completed and the positioning for the next work location is completed, the self-propelled vehicle body automatically returns to the work travel speed and travels to the next work location at this work travel speed. Can be done.

  Therefore, according to the fourth aspect of the invention, the vehicle is driven at a set low speed so that the positioning can be easily performed in the final turning range, but when the positioning is completed, the traveling speed is automatically returned to the traveling speed before the low-speed traveling. It is possible to easily resume the operation on the operation surface.

In the fifth invention, in the configuration of the first or second invention,
A descent operation detecting means for detecting a descent operation of the work device connected to the descent work state and the up non-work state so as to be able to be raised and lowered freely;
When the measured turning angle by the turning angle measuring means becomes a set turning angle and the descending operation detecting means is in a detection state, the control means travels before the self-propelled vehicle shifts to the set low speed. In order to travel at a speed, the vehicle body is shifted based on the measurement information by the turning angle measuring means and the detection information by the descending operation detecting means.

  When the self-propelled vehicle body reaches the end turning range and starts traveling at the set low speed, it steers while moving the self-propelled vehicle body at low speed to align it with the next work location, and when this alignment is completed, The work is performed in such a manner that the work device is lowered to the lowered work state and the work portion is moved to work. When the work device is lowered, it is detected by the descent operation detecting means, and the control means performs the traveling shift of the self-propelled vehicle based on the measurement information by the turning angle measuring means and the detection information by the descent operation detecting means. The vehicle travels by returning the traveling speed before traveling at the set low speed. As a result, when the turning operation is completed and the position adjustment for the next work location is completed and the work device is lowered, the self-propelled vehicle body automatically returns to the work travel speed and the next work travel speed is reached. It can be made to drive | work the work part.

  Therefore, according to the fifth aspect of the present invention, although the vehicle is driven at a set low speed so that the positioning can be easily performed in the final turning range, when the positioning is completed, if the lowering operation of the working device is performed, a special shift effort is reduced. Even if it is not applied, the traveling speed returns to the traveling speed before the low-speed traveling, and the operation traveling can be easily resumed from the operation surface.

In the sixth invention, in any one of the first to fifth inventions,
The low speed setting means is configured to be manually operable so that the setting low speed can be changed.

  That is, when the low speed setting means is manually operated, the set low speed is changed and set, and the speed at which the self-propelled vehicle body travels at a low speed in the end turn range changes. Thus, for example, when the ground of the headland is rough, if the set low speed is appropriately changed and set, the steering operation in the final turn range can be performed appropriately and quickly regardless of the headland condition. The running speed can be adjusted.

  Therefore, according to the sixth aspect of the invention, by changing and setting the set low speed according to the headland condition, the traveling speed appearing in the final turn range is adjusted to an easy-to-steer operation, and the headland condition Regardless of the position, the alignment can be performed appropriately and quickly.

Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, an engine 4 provided at a front portion of a vehicle body frame 3 is provided on a self-propelled vehicle body having a pair of left and right steering operations and a front wheel 1 that can be driven and a pair of left and right drive wheels 2 that can be driven. The vehicle body frame is provided with an installed driving part, a steering handle 5 provided on the rear side of the driving part so as to steer the left and right front wheels 1, and a driving part equipped with a driving seat 6 provided on the rear part of the vehicle body. 3 is provided with a pair of left and right lift arms 8 and a power take-out shaft 9 to form a tractor, and a link using the pair of left and right lift arms 8 at the rear of the vehicle body of the tractor. The rotary tiller 11 is connected via the mechanism 10 and the driving force of the engine 4 is transmitted from the power take-out shaft 9 to the rotary tiller 11 via the rotary shaft 12 so as to be used for riding type tillage. I have configured the machine.

  This cultivator performs a cultivating work. When the elevating lever 15 provided in the operation unit is swung, the elevating cylinder 16 located inside the transmission case 7 swings the pair of left and right lift arms 8 up and down. By operating and swinging the link mechanism 10 up and down with respect to the vehicle body frame 3, the rotary tiller 11 is in a descending work state in which the tilling rotor 11a contacts the ground, and the tilling rotor 11a is lifted high from above the ground. Move up and down to work state. When the rotary cultivator 11 is moved down and the tractor is caused to travel, the rotary cultivator 11 is cultivated by the cultivating rotor 11a that is rotationally driven.

  The driving force from the output shaft of the engine 4 is input to a main transmission 17 provided at the front of the transmission case 7, and the output of the main transmission 17 is an auxiliary transmission (shown in FIG. And the output from the auxiliary transmission is input from the transmission case 7 to the front wheel drive case 19 via the rotary shaft 18 and transmitted to the left and right front wheels 1. It is configured. The main transmission 17 is a variable displacement hydraulic pump (not shown) to which the driving force from the engine 4 is input, and a hydraulic motor that is driven by the pressure oil from the hydraulic pump and outputs to the auxiliary transmission. (Not shown), which is a hydrostatic continuously variable transmission.

  As a result, when the swash plate angle of the hydraulic pump in the main transmission 17 is changed, the driving force from the engine 4 is changed by the main transmission 17 to the forward and reverse driving forces, and the forward drive On both the rear and reverse sides, the gears are steplessly transmitted and transmitted to the left and right rear wheels 2 and the left and right front wheels 1, and the self-propelled vehicle travels forward and backward and travels steplessly on both the forward and reverse sides. To do.

  As shown in FIG. 2, a control means 21 is linked to a speed change actuator 20 interlocked with the main transmission 17, and the control means 21 includes a traveling speed detection means 22 provided in the mission case 7, the steering handle. 5, a cutting angle sensor 23 linked to 5, a low speed setting means 24 and a mode selection means 25 provided in the operating section, and a lowering operation detection means 26 linked to the elevating lever 15 are linked. A shift sensor 27 provided in the main transmission 17 is also linked to the control means 21.

  The speed change actuator 20 is linked to a speed change operation part (not shown) of the main speed change device 17, and by operating this speed change operation part, the swash plate angle of the hydraulic pump of the main speed change device 17 is changed. The main transmission 17 is then shifted.

  The shift sensor 27 of the main transmission 17 detects the shift state of the main transmission 17 based on the operation position of the shift operation unit in the main transmission 17 and feeds back the detected shift state to the control means 21 as an electrical signal. .

  The traveling speed detection means 22 is composed of a rotation sensor that detects and acts on a rotation shaft (not shown) positioned so as to transmit the output from the auxiliary transmission to the front and rear wheels 1 and 2 in the mission case 7. The number of rotations is detected as the traveling speed of the self-running vehicle body, and the detection result is output to the control means 21 as an electrical signal.

  The turning angle sensor 23 detects the rotation angle of the steering handle 5 as a turning angle of the front wheel 1 from the straight traveling direction to the lateral direction, and outputs the detection result to the control means 21 as an electrical signal.

As shown in FIG. 3, the self-propelled vehicle body that has completed the tillage traveling of the work location A is swung toward the next work location C, and the next vehicle operation location is operated by steering the self-propelled vehicle body in the final turn range Z. When aligning to C, it is easier to align if the vehicle travels at a low speed. As a result, the low speed setting means 24 sets a low traveling speed that facilitates the alignment, and outputs the set low speed Vb to the control means 21 as an electrical signal.
Further, the low speed setting means 24 is configured by an artificially operable rotary potentiometer provided to manually operate the operation tool 24a, and the set low speed Vb has a different speed value by rotating the operation tool 24a. Change to something and set.

  The descent operation detecting means 26 is composed of a rotary potentiometer linked to the elevating lever 15 and detects that the descent operation of the rotary tiller 11 has been performed by detecting the swing of the elevating lever 15 to the “down” side. The detection result is converted into an electrical signal and output to the control means 21.

The mode selection means 25 is composed of a changeover switch that can be switched to four operation positions of “cut”, “time mode”, “distance mode”, and “descent mode” by rotating the operation tool 25a. A command corresponding to the position is converted into an electrical signal and output to the control means 21.
In other words, when the operation is switched to “cut”, a cut command for turning off the shift control by the control means 21 is output. When the operation is switched to the “time mode”, an input command for turning on the shift control in the time mode by the control means 21 is output. When the operation is switched to the “distance mode”, an input command for turning on the shift control in the distance mode by the control means 21 is output. When the operation is switched to the “descent mode”, an on command for turning on the shift control in the descent mode by the control means 21 is output.

  The control means 21 includes a turning angle measurement means 30, an elapsed time measurement means 31, and a travel distance measurement means 32 configured using a microcomputer.

  As shown in FIG. 3, when the self-propelled vehicle body travels with the left and right front wheels 1 being steered from the straight direction to the lateral direction, the self-propelled vehicle body turns and the left and right front wheels 1 are steered. The turning angle of the self-propelled vehicle body from the start point ST increases as the self-propelled vehicle body travels. As a result, the turning angle measuring means 30 performs a measurement operation based on a command from the control means 21, and measures the traveling time using a timer as the self-propelled vehicle body turns, and the measured traveling time, The turning angle D from the turning start point ST of the self-running vehicle body is measured based on the detected turning angle by the turning angle sensor 23 and the detected traveling speed by the traveling speed detecting means 22.

  The elapsed time measuring means 31 measures and operates based on a command from the control means 21, and measures the time that has elapsed since the self-propelled vehicle body reached the turning end stage range Z (see FIG. 3) and started traveling at the set low speed Vb. I will do it.

  The travel distance measuring means 32 performs a measurement operation based on a command from the control means 21, measures a travel time using a timer, and based on the measured travel time and the travel speed detected by the travel speed detection means 22, The travel distance traveled after the traveling vehicle body has reached the end-of-turn range Z and started traveling at the set low speed Vb is measured.

  The control means 21 is configured by using a microcomputer. As shown in FIG. 5, when the mode selection means 25 is operated to “OFF”, the control means 21 shifts based on a cut instruction from the mode selection means 25. The control is turned off, and the shift control of the main transmission 17 based on information such as the turning angle sensor 23 is stopped. When the mode selection unit 25 is operated in the “time mode”, the time mode shift control is turned on based on the input command from the mode selection unit 25, and the mode selection unit 25 is operated in the “distance mode”. If the mode selection means 25 is in the “down mode”, the distance mode shift control is turned on based on the ON command from the mode selection means 25. The descent mode shift control is turned on.

The control means 21 in the time mode shift control on state operates as shown in FIG.
That is, the traveling speed detected by the traveling speed detecting means 22 and the detected turning angle detected by the turning angle sensor 23 are continuously read, and the measured turning angle Da obtained by the turning angle measuring means 30 is input to the storage unit. If the measured turning angle Da is determined to be equal to the set turning angle Db, the detected traveling speed Va by the traveling speed detecting means 22 when this determination is made is the low speed setting means. It is determined whether or not it is larger than the set low speed Vb by 24. When it is determined that the detected traveling speed Va is not greater than the set low speed Vb, the speed reduction operation of the main transmission 17 is not performed. When it is determined that the detected travel speed Va is larger than the set low speed Vb, the main shift lever 35 (for storing the detected travel speed Va in the storage unit and manually shifting the main transmission 17) Prior to the detection information from the potentiometer 37 (see FIG. 2) for detecting the operation position of FIG. 2), the main transmission 17 is set so that the travel speed Va detected by the travel speed detection means 22 becomes the set low speed Vb. A deceleration operation is performed, and the elapsed time measuring means 31 is caused to perform a measurement operation. The main shift to a shift state where the detected traveling speed Va becomes the set low speed Vb until the measured elapsed time Ta by the elapsed time measuring means 31 becomes equal to the set elapsed time Tb set by the elapsed time setting means 38 (see FIG. 2). The apparatus 17 is maintained. When the measured elapsed time Ta by the elapsed time measuring means 31 becomes equal to the set elapsed time Tb, the main transmission 17 is shifted before deceleration so that the detected travel speed Va by the travel speed detecting means 22 becomes the stored detected travel speed by the storage unit. The operation of returning to the state is performed, and at the same time, the storage of the storage detection traveling speed by the storage unit is canceled.

The control means 21 in the distance mode shift control ON state operates as shown in FIG.
That is, the traveling speed detected by the traveling speed detecting means 22 and the detected turning angle detected by the turning angle sensor 23 are continuously read, and the measured turning angle Da obtained by the turning angle measuring means 30 is input to the storage unit. If the measured turning angle Da is determined to be equal to the set turning angle Db, the detected traveling speed Va by the traveling speed detecting means 22 when this determination is made is the low speed setting means. It is determined whether or not it is larger than the set low speed Vb by 24. When it is determined that the detected traveling speed Va is not greater than the set low speed Vb, the speed reduction operation of the main transmission 17 is not performed. When it is determined that the detected traveling speed Va is greater than the set low speed Vb, the detected traveling speed Va is stored in the braking / memory unit, and the detection information from the potentiometer 37 of the main transmission lever 35 is prioritized, The main transmission 17 is decelerated so that the travel speed Va detected by the travel speed detection means 22 becomes the set low speed Vb, and the travel distance measurement means 32 performs a measurement operation. The main shift to a shift state where the detected travel speed Va becomes the set low speed Vb until the travel distance La measured by the travel distance measuring means 32 becomes equal to the set travel distance Lb set by the travel distance setting means 39 (see FIG. 2). The apparatus 17 is maintained. When the measured travel distance La by the travel distance measuring means 32 becomes equal to the set travel distance Lb, the main transmission 17 is shifted before deceleration so that the detected travel speed Va by the travel speed detecting means 22 becomes the stored detected travel speed by the storage section. The operation of returning to the state is performed, and at the same time, the storage of the storage detection traveling speed by the storage unit is canceled.

The control means 21 that has entered the descent mode shift control ON operates as shown in FIG.
That is, the traveling speed detected by the traveling speed detecting means 22 and the detected turning angle detected by the turning angle sensor 23 are continuously read, and the measured turning angle Da obtained by the turning angle measuring means 30 is input to the storage unit. If the measured turning angle Da is determined to be equal to the set turning angle Db, the detected traveling speed Va by the traveling speed detecting means 22 when this determination is made is the low speed setting means. It is determined whether or not it is larger than the set low speed Vb by 24. When it is determined that the detected traveling speed Va is not greater than the set low speed Vb, the speed reduction operation of the main transmission 17 is not performed. When it is determined that the detected travel speed Va is greater than the set low speed Vb, the detected travel speed Va is stored in the storage unit, and the detected travel speed from the potentiometer 37 of the main transmission lever 35 is prioritized. The main transmission 17 is decelerated so that the traveling speed Va detected by the speed detecting means 22 becomes the set low speed Vb. The main transmission 17 is maintained and operated in a shift state in which the detected traveling speed Va becomes the set low speed Vb until it is determined that the lowering operation of the rotary tiller 11 has been performed based on the detection information by the lowering operation detection means 26. When it is determined that the lowering operation of the rotary tiller 11 has been performed, the main transmission 17 is returned to the speed change state before the deceleration so that the travel speed Va detected by the travel speed detector 22 becomes the travel speed detected by the storage unit. At the same time, the storage of the detected traveling speed by the storage unit is canceled.

  In both the elapsed time setting means 38 and the travel distance setting means 39, the set elapsed time Ta by the elapsed time setting means 38 and the set travel distance La by the travel distance setting means 39 are changed to those having different time lengths and distance lengths. Therefore, it is configured as a setting means that can be manually operated.

  That is, when performing the tilling work, as shown in FIG. 3, when the plowing traveling at the work location A is finished, the self-propelled vehicle body is turned on the headland B to move to the next working location C adjacent to the previous working location A. In the final turning range Z, the self-propelled vehicle body is steered and aligned with the next work location C. At the next work location C, the rotary tiller 11 is moved with respect to the work location C. The farming is carried out while properly positioned so that no tillage leakage occurs between the work place C and the previous work place A. In this cultivator, when the cultivating traveling at the work location A is completed, the mode selection means 25 is set to “time mode”, “distance mode”, If the control means 21 is in the state where the shift control is turned on if the operation position is in any of the “down mode”, the turning angle measuring means 30 measures the turning angle of the self-propelled vehicle body, When the vehicle body makes a turn of about 135 degrees from the turning start point ST and reaches the turning end stage range Z, the measured turning angle Da by the turning angle measuring means 30 becomes the set turning angle Db, and the control means 21 operates the speed change actuator 20. Then, the main transmission 17 is shifted to a speed lower than that during tillage travel, and the self-propelled vehicle body is automatically decelerated to a set low speed Vb lower than the tillage travel speed set by the low speed setting means 24. Run Go, self-propelled vehicle body to be able to self-propelled vehicle body to be able to steering operation while low speed to suit precisely readily located next working position C.

  When the mode selection means 25 is operated in the “time mode”, when the self-propelled vehicle body reaches the turning end range Z and starts to decelerate to the set low speed Vb, the elapsed time measurement means 31 When the self-propelled vehicle has finished traveling in the end turn range Z and has reached the vicinity of the beginning of the next work location C, the elapsed time Ta measured by the elapsed time measuring means 31 is set to the elapsed time Tb set by the elapsed time setting means 38. Then, the control means 21 operates the speed change actuator 20 to return the main speed change device 17 to the speed change state before the speed reduction operation in the turning end range Z first, and the travel speed of the self-propelled vehicle body is set as described above. It automatically returns to the travel speed before the time when the speed is changed to the low speed Vb, and the alignment of the self-propelled vehicle body with the next work location C has been completed. It is hard to generate tillage leakage Thus, the next work location C is cultivated so that the next work location C is cultivated and traveled at the same cultivation speed as when the self-propelled vehicle cultivated the previous work location A. be able to.

  When the mode selection means 25 is operated to the “distance mode”, the travel distance measuring means 32 is activated when the self-propelled vehicle body reaches the end turning range Z and starts to decelerate to the set low speed Va. When the self-propelled vehicle finishes traveling in the end turning range Z and reaches the vicinity of the beginning of the next work location C, the measured travel distance La by the travel distance measuring means 32 becomes the set travel distance Lb by the travel distance setting means 39. Then, the control means 21 operates the speed change actuator 20 to return the main speed change device 17 to the speed change state before the speed reduction operation in the turning end stage range Z first, and the travel speed of the self-propelled vehicle body becomes the set low speed. It automatically returns to the traveling speed before the time when the speed is changed to Vb, and the alignment of the self-propelled vehicle body with the next work location C is completed, and the tilling is performed between the next work location C and the previous work location A. To prevent leakage In addition, it is possible to cultivate the next work location C so that the next work location C is cultivated at the same tilling speed as when the self-propelled vehicle cultivated the previous work location A. it can.

  When the mode selection means 25 is operated to the “descent mode”, the self-propelled vehicle body is aligned with the next work location C in the state where the self-propelled vehicle body is traveling at the set low speed Vb in the turning end range Z. When the position adjustment is completed and the next working portion C starts to be cultivated, when the elevating lever 15 is operated and the cultivating device 11 is lowered, the descent operation detecting means 26 enters the detection state and the control means. 21 operates the speed change actuator 20 to return the main speed change device 17 to the speed change state before the speed reduction operation in the turning end range Z first, and the traveling speed of the self-running vehicle body is shifted to the set low speed Vb. It automatically returns to the previous traveling speed prior to the time when it has been made so that no tillage leakage occurs between the next work location C and the previous work location A, and the self-propelled vehicle body moves to the previous work location A. For the same tillage As tilling traveling next working position C can continue to tilling the next working position C at a line speed.

  The engine 4 is configured as a common rail type diesel engine and has characteristics as shown in FIG. As shown in FIG. 2, the speed adjusting mechanism 40 of the engine 4 is linked to the control means 21.

  The control means 21 detects the steering state of the front wheel 1 based on the information detected by the turning angle sensor 23, and the front wheel 1 is in a steering state in which the front wheel 1 moves straight or slightly swings from the straight direction to the side. For example, it is determined that the self-propelled vehicle body is in a working traveling state, and if the front wheel 1 is in a steering state in which the front wheel 1 swings sideways beyond a set angle, it is determined that the self-propelled vehicle body is in a turning traveling state. When it is determined that the self-propelled vehicle body is in a working travel state, the speed control mechanism 40 is operated on the high speed side so that the engine 4 rotates in a rotational speed range nz higher than the rotational speed na exhibiting the maximum torque Tm, When it is determined that the self-propelled vehicle body is in a turning traveling state, the speed control mechanism 40 is decelerated so that the engine 4 has a rotational speed na that exhibits the maximum torque Tm or a rotational speed nb that exhibits 90% of the maximum torque Tm. Manipulate.

  In other words, at the time of work, the engine 4 is driven at a rotational speed higher than the maximum torque point so that an engine stop does not easily occur even when a high driving load is generated and the engine rotational speed is reduced. When turning, the driving load is lighter than the work load, and even if the load increases and the engine speed decreases, it is difficult for the engine to stop. The engine 4 is driven at a lower rotational speed than during work so that less fuel is required.

[Another Example]
In addition to the information detected by the turning angle sensor 23 and the turning angle measuring means 30 for measuring the turning angle based on the vehicle speed as in the above embodiment, the turning angle is measured based on the detection information by the angular velocity sensor for detecting turning. The turning angle is measured based on the turning angle measuring means configured as described above, information detected by the turning angle sensor 23, the vehicle speed, and the Ackermann principle of the front wheel support mechanism that supports the front wheel 1 so as to be able to swing and steer. The turning angle measuring means configured as described above may be employed, and in either case, the object of the present invention can be achieved.

  As in the above embodiment, by decelerating the main transmission 17, the self-propelled vehicle body can be decelerated in the turning end range Z, and the sub-transmission is decelerated or the engine 4 is rotated at a lower speed. Therefore, even if the self-propelled vehicle body can be decelerated within the turning end range Z, the object of the present invention can be achieved, and any configuration may be adopted.

  The present invention can be applied to a vehicle that performs various operations such as rice planting in addition to a field cultivator. The field cultivator and the rice transplanter are collectively referred to as a work vehicle, and the rotary cultivator 11 and the seedling planting device are collectively referred to. This will be referred to as work device 11.

Overall side view of riding-type field cultivator Block Diagram Illustration of turning Engine characteristics Shift control flow chart Shift control flow chart Shift control flow chart Shift control flow chart

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front wheel 11 Working device 21 Control means 22 Traveling speed detection means
23 Cutting angle sensor 24 Low speed setting means 26 Lowering operation detecting means 30 Turning angle measuring means 31 Elapsed time measuring means 32 Traveling distance measuring means
D Turning angle Da Measuring turning angle Db Setting turning angle La Measuring traveling distance Lb Setting traveling distance
ST Turning start point Ta Measurement elapsed time Tb Set elapsed time Va Detected travel speed Vb Set low speed

Claims (6)

A running speed detecting means for detecting the running speed of the self-propelled vehicle body and a turning angle sensor for detecting a turning angle from the straight traveling direction of the front wheel are provided.
Based on the detected turning angle by the turning angle sensor and the detected traveling speed by the traveling speed detecting means, a turning angle measuring means for measuring a turning angle from the turning start point of the self-propelled vehicle body is provided,
Provide low speed setting means to set the low speed setting of the self-propelled vehicle body alignment running,
When the measured turning angle by the turning angle measuring means becomes the set turning angle, based on the detection information by the running speed detecting means and the measurement information by the turning angle measuring means so that the self-running vehicle body runs at the set low speed. A work vehicle provided with a control means for shifting the traveling speed of the self-propelled vehicle body.   The control means detects the traveling speed detected by the traveling speed detecting means when the measured turning angle by the turning angle measuring means becomes a set turning angle and the measured turning angle by the turning angle measuring means becomes a set turning angle. 2. The work vehicle according to claim 1, wherein when the vehicle speed is higher than the set low speed, the self-propelled vehicle body is shifted so that the self-running vehicle body travels at the set low speed. An elapsed time measuring means for measuring the time elapsed since the self-propelled vehicle body started traveling at a low speed set by the low speed setting means;
When the elapsed time measured by the elapsed time measuring means reaches the set elapsed time, the elapsed time is adjusted so that the self-propelled vehicle shifts to a travel speed before the self-propelled vehicle shifts to the set low speed. The work vehicle according to claim 1 or 2, wherein the work vehicle is configured to perform a traveling shift of the self-propelled vehicle body based on measurement information obtained by the measuring means. A self-propelled vehicle body is provided with a travel distance measuring means for measuring the travel distance traveled after the vehicle starts running at a low speed set by the low speed setting means;
When the travel distance measured by the travel distance measurement means becomes a set travel distance, the travel distance of the control means is such that the self-propelled vehicle shifts to a travel speed before shifting to the set low speed. The work vehicle according to claim 1 or 2, wherein the work vehicle is configured to perform a traveling shift of the self-propelled vehicle body based on measurement information obtained by the measuring means. A descent operation detecting means for detecting a descent operation of the work device connected to the descent work state and the up non-work state so as to be able to be raised and lowered freely;
When the measured turning angle by the turning angle measuring means becomes a set turning angle and the descending operation detecting means is in a detection state, the control means travels before the self-propelled vehicle shifts to the set low speed. 3. The vehicle is configured to perform a traveling shift of the self-propelled vehicle body based on measurement information by the turning angle measuring means and detection information by the descending operation detecting means so as to travel at a speed. The work vehicle described.   The work vehicle according to any one of claims 1 to 5, wherein the low speed setting means is configured to be manually operable so that the setting low speed can be changed.

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