JP2006096134A - Turning control device of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turning control device for a working vehicle capable of avoiding a drop of the operating easiness when changing-over is made from the straight running condition into a left-turning or right-turning condition. <P>SOLUTION: The turning control device of the working vehicle is equipped with a continuously variable transmission device 7 for straight running and a continuously variable transmission device 8 for turning, and these transmission devices are put under shift control on the basis of the sensing speed of speed sensing means 58 and 59 so that the outputs of the two become equal speed in straight running. In turning, the outputs of the device for straight running and for turning are transmitted to an outer running device and an inner running device, respectively, so as to generate a speed difference between the outer and the inner. The shifting operation speed of the transmission device 8 for turning at that time is made greater than the shifting operation speed of the transmission device 7 for straight running on the basis of a speed command means 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a straight transmission state in which the output of a continuously variable continuously variable transmission is transmitted to each of the left and right traveling devices, the output of the continuously variable continuously variable transmission is transmitted to the right traveling device, and is used for turning. A transmission state for turning left that transmits the output of the continuously variable transmission to the left traveling device, and an output of the continuously variable transmission for straight travel to the left traveling device and the continuously variable transmission for turning Transmission state switching means capable of switching output to the right turning transmission state for transmitting output to the right traveling device, turning command means for commanding straight, left turning and right turning, and speed command for commanding traveling speed Means, a speed control means for shifting the straight-line continuously variable transmission and the turning continuously variable transmission, and the transmission state switching means so as to be in a traveling state commanded by the turning command means. And a traveling state switching control means for performing switching operation. When the speed control means is commanded to go straight by the turning command means, one of the continuously variable continuously variable transmission and the continuously variable transmission for turning A speed change operation is performed so that the traveling speed commanded by the speed command means is obtained, and the other continuously variable transmission is set to the same speed as the speed detected by the speed detection means for detecting the speed of the one continuously variable transmission. When the left turn and the right turn are commanded by the turn command means, the straight variable continuously variable transmission device is commanded by the speed command means. Turning a work vehicle configured to execute a turning control process for performing a speed change operation so as to achieve a set traveling speed, and for performing a speed change operation so that the continuously variable transmission for turning becomes a target speed for turning. The present invention relates to a control device.

  In the conventional configuration of such a turning control device for a work vehicle, a mechanical command unit that links speed command means, turning command means, and these command means with a continuously variable continuously variable transmission and a continuously variable transmission for turning. Operation linkage means, and when the operation linkage means is commanded to go straight by the turn command means, the output of the continuously variable transmission for straight running is transmitted to each of the left and right traveling devices, and A speed detecting means for speed-changing the stepped transmission so that the traveling speed instructed by the speed commanding means is achieved, and for detecting the speed of the continuously variable transmission for turning, the speed of the continuously variable continuously variable transmission; When the left and right turns are commanded by the turn command means, the output of the continuously variable transmission for straight travel is transmitted to one of the travel devices and the turn is made. The output of the continuously variable transmission for the other traveling device The continuously variable transmission for straight travel is operated to change to the traveling speed commanded by the speed command means, and the continuously variable transmission for turning is set to the target speed for turning. (See, for example, Patent Document 1).

That is, such a turning control device for a work vehicle is configured so that, in the straight traveling state, the outputs of the continuously variable transmission for straight traveling are transmitted to the left and right traveling devices, respectively. Compared to the configuration in which the output of the transmission is transmitted to each of the left and right traveling devices, straight travel due to errors in the production accuracy of continuously variable transmissions installed separately on the left and right, and operational accuracy due to secular change, etc. This makes it possible to avoid the inconvenience of causing a shift in the traveling speed of the left and right traveling devices during traveling and preventing the work vehicle from moving straight even if the straight command is commanded by the turning command means.
Japanese Patent No. 3174515

In addition, as a configuration for shifting the straight-line continuously variable transmission and the turning continuously variable transmission, it is conceivable to provide a speed control means using a microcomputer instead of the mechanical operation linking means.
That is, when the speed control means is instructed to go straight by the turning command means, one of the continuously variable transmission for straight running and the continuously variable transmission for turning is set by the speed command means. The speed change operation is performed so that the commanded traveling speed is obtained, and the speed of the other continuously variable transmission is changed so as to be the same as the speed detected by the speed detecting means for detecting the speed of the one continuously variable transmission. When a straight-ahead control process is executed and a left turn and a right turn are commanded by the turn command means, the continuously variable continuously variable transmission is shifted so as to have a traveling speed commanded by the speed command means. It is conceivable to perform a turning control process for operating and changing the speed of the continuously variable transmission for turning so as to be the target speed for turning.

  In the above-mentioned turning control device for a work vehicle, when one of the continuously variable transmission device of the straight traveling continuously variable transmission device and the turning continuously variable transmission device is shifted in the straight traveling control process, the other continuously variable transmission device is operated. Since the speed change operation is performed so that the speed change is the same as that of the one continuously variable transmission while the speed change operation follows the speed change operation of the one continuously variable transmission, the rotational speed of the other continuously variable transmission is The rotational speed of the continuously variable transmission for turning and the rotational speed of the continuously variable continuously variable transmission differ from each other due to the time lag until the rotational speed is the same as that of the continuously variable transmission. When the continuously variable transmission is greatly shifted, the rotational speed of the continuously variable transmission for turning and the rotational speed of the continuously variable continuously variable transmission are considerably different.

  Thus, if the rotational speed of the continuously variable transmission for turning deviates from the rotational speed of the continuously variable continuously variable transmission, for example, when a straight command is commanded by the turn command means, the continuously variable transmission for turning If the device is operated to change the speed to be the same as that of the continuously variable transmission for straight travel, and if the turn command means commands a left turn while commanding a rapid deceleration by the speed command means, the turning continuously variable In a state where the rotational speed of the transmission is much higher than the rotational speed of the continuously variable transmission for straight travel, the output of the continuously variable continuously variable transmission is transmitted to the left and right traveling devices respectively. Since the output of the continuously variable transmission is transmitted to the right traveling device and the output of the continuously variable transmission for turning is transmitted to the left traveling device, it is switched to the left turning transmission state. Despite being commanded, once to the right Will be times, that amount extra turning operation there is a risk that lowering the equivalent operability required.

  Alternatively, when a straight command is commanded by the turning command means, the turning continuously variable transmission is operated so as to have the same speed as the continuously variable continuously variable transmission, and the speed command means is rapidly decelerated. When turning right is commanded by the turning command means, the output of the continuously variable continuously variable transmission is in a state where the rotational speed of the continuously variable continuously variable transmission is much higher than the rotational speed of the continuously variable continuously variable transmission. From the straight transmission state in which the left and right traveling devices are transmitted, the output of the continuously variable transmission for straight traveling is transmitted to the left traveling device and the output of the continuously variable transmission for turning is transmitted to the right traveling device. If the turn command means commands a right turn, the turn will turn to the right more than necessary, which may lead to a decrease in operability, such as inability to operate as intended. .

  The present invention has been made in view of the above circumstances, and its purpose is that when a turn command means commands a left turn or a right turn while a travel speed is rapidly changed by a speed command means. Another object of the present invention is to provide a work vehicle turning control device capable of avoiding a decrease in operability when switching from a straight traveling state to a left turning state or a right turning state.

The turning control device for a work vehicle according to the present invention includes a straight traveling state in which the output of the continuously variable transmission for straight travel is transmitted to each of the left and right traveling devices, and the output of the continuously variable continuously variable transmission for the right traveling device. And the output of the continuously variable transmission for turning to the left traveling device, and the output of the continuously variable transmission for straight travel to the left traveling device and the turning A transmission state switching means capable of switching to a right turning transmission state for transmitting the output of the continuously variable transmission for the right traveling device, a turn command means for commanding straight, left turn, and right turn; Speed command means for instructing the traveling speed, speed control means for shifting the straight-line continuously variable transmission and the continuously variable transmission for turning, and a traveling state commanded by the turning command means A traveling state in which the transmission state switching means is switched to Replacement control means, and when the speed control means is commanded to go straight by the turning command means, one of the continuously variable continuously variable transmission and the continuously variable transmission for turning Speed detecting means for shifting the continuously variable transmission so as to have the traveling speed commanded by the speed command means and for detecting the speed of the one continuously variable transmission for the other continuously variable transmission. When the left turn and the right turn are commanded by the turn command means, the continuously variable transmission for straight running is executed. A turning control process is executed in which a speed change operation is performed so that the traveling speed commanded by the speed command means is achieved, and the continuously variable transmission for turning is operated so as to be a target speed for the turn. Composed of:
The first characteristic configuration is that the speed control means sets a speed change operation speed for speed changing the continuously variable transmission so that the speed detection means becomes the same speed as the speed detected by the speed detection means in the straight-ahead control processing. The straight variable continuously variable transmission and the swivel continuously variable transmission are shifted in a state in which the variable speed is set to be greater than the shift operation speed at which the continuously variable transmission is shifted so that the travel speed commanded by It is in the point comprised as follows.

  According to the first characteristic configuration, when the rectilinear command is commanded by the turning command means, one of the continuously variable continuously variable transmission and the continuously variable transmission for turning is used as the speed command means. To change the speed of the other continuously variable transmission to the same speed as the detection speed of the speed detecting means for detecting the speed of the one continuously variable transmission. However, in such a speed change operation, a speed change operation speed for changing the speed of the continuously variable transmission so as to be the same as the speed detected by the speed detection means is the travel commanded by the speed command means. The time lag until the rotational speed of the other continuously variable transmission becomes the same as the rotational speed of one continuously variable transmission by increasing the speed of the continuously variable transmission so that the speed is the same as the speed of the other continuously variable transmission. Reduce as much as possible, Becomes as much as possible can be prevented and the rotational speed of the continuously variable transmission for linear and rotational speed of the continuously variable transmission is shifted greatly for times.

  When the turn command means commands left turn and right turn, the rotation speed of the continuously variable transmission for turning does not greatly deviate from the rotation speed of the continuously variable transmission for straight travel. From the straight transmission state where the output of the continuously variable transmission is transmitted to the left and right traveling devices, the output of the continuously variable transmission is transmitted to one of the left and right traveling devices and Since the output of the step transmission is switched to a turning transmission state in which the output of the step transmission is transmitted to the other traveling device, for example, when the straight command is commanded by the turning command means, the continuously variable transmission for turning is changed to the continuously variable transmission for straight running When shifting the speed to the same speed as the device and commanding a left turn by the turn command means while rapidly decelerating by the speed command means, it is temporarily turned to the right even though the left turn is commanded. Will turn and its If an extra turning operation is required, or if a right turn is commanded by the turn command means while suddenly decelerating by the speed command means, it will turn to the right more than necessary and the desired operation can be performed. It is possible to accurately avoid a decrease in operability such as disappearance.

  Therefore, even when turning is commanded by the turning command means while the traveling speed is suddenly changed by the speed command means, the operability is accurately reduced when switching from the straight running state to the left turning state or the right turning state. It came to provide the turning control device of the work vehicle which can be avoided.

  According to a second characteristic configuration of the present invention, in addition to the first characteristic configuration, the speed control unit includes a mechanical servo unit and a shift control unit that operates a shift actuator to perform a shift operation. The mechanical servo means shifts the linearly variable continuously variable transmission so as to have a traveling speed commanded as a change in operating position by a position change operation-type shift operating tool as the speed command means. The speed change control means is configured to change the speed of the continuously variable transmission for turning by the speed change actuator so that the speed is the same as the speed detected by the speed detection means. Features a point.

  According to the second characteristic configuration, by operating the position changing operation type shifting operation tool, the speed change operation of the continuously variable continuously variable transmission device is performed by the mechanical servo unit, and the shift control unit detects the speed detecting unit. The continuously variable transmission for turning is changed so as to have the same speed as the speed.

  Therefore, even in the event of a failure of the speed change control means, the linearly variable continuously variable transmission can be changed by the mechanical servo means, and means suitable for implementing claim 1 can be obtained.

According to a third characteristic configuration of the present invention, in addition to the first or second characteristic configuration, the turning command means is arranged so that the straight turn command position for commanding the straight travel is positioned adjacent to the straight travel command position and the left turn is performed. And a right turn command range for commanding a right turn adjacent to the straight advance command position, and an operation position of the turn command means. Operating position detecting means is provided for detecting the travel speed, and the continuously variable transmission for straight traveling and the continuously variable transmission for turning decelerate the traveling speed of the traveling device on the turning side from the traveling speed of the traveling device on the straight traveling side. A first turning state, a second turning state in which the turning-side traveling device is stopped, and a third turning in which the traveling direction of the turning-side traveling device is made to run in a direction opposite to the traveling direction of the straight-ahead traveling device. Configured to be operated In each of the left turn command range and the right turn command range, as the turn command means is operated to the side away from the straight advance command position, the first turn state, the second turn state, and The turning operation mode change setting means for artificially changing and setting the relationship between the operation position in the turning command range of the turning command means and the target turning state on condition that the third turning state is sequentially commanded. And the speed control means is in a turning state determined corresponding to the operation position of the turning command means based on the detection information of the operation position detection means and the setting information of the turning operation mode change setting means. Thus, the linearly variable continuously variable transmission and the continuously variable continuously variable transmission are configured to perform a speed change operation.
According to the third characteristic configuration, when the turning command means is operated to the side away from the straight command position in the turning command range, the operation position of the turning command means is detected by the operation position detecting means, Based on the detection result of the operation position detection means, the speed detection means causes the first turning state in which the traveling speed of the turning-side traveling device is decelerated with the traveling speed of the other traveling device, and the second turning that stops the turning-side traveling device. And a third turning state in which the traveling device on the turning side travels in a direction opposite to the traveling direction of the other traveling device. At that time, the speed control means is speed-changed to a target turning state set in advance corresponding to the operation position of the turning command means. The target turning state is changed by the turning operation mode change setting means. It can be changed artificially. That is, the turning operation mode change setting means can arbitrarily change and set the relationship between the operation position in the turning command range of the turning command means and the target turning state so that the operator can easily operate. Can do.

  Therefore, it is possible to make an operation form that makes it easy to handle the turning operation in accordance with the difference in the operation feeling of the operator, and a suitable means for implementing claim 1 or 2 can be obtained. .

  According to a fourth characteristic configuration of the present invention, in addition to the third characteristic configuration, the turning operation mode change setting means is operated to the side where the turning command means moves away from the straight command position in the first turning state. As the third turning state, the turning command means sets the mode for increasing the amount of deceleration when the traveling speed of the turning side traveling device is decelerated from the traveling speed of the straight traveling side traveling device. A mode is set in which the traveling speed when the traveling direction of the turning-side traveling device is caused to travel in the direction opposite to the traveling direction of the traveling device on the straight-traveling side is increased as the operation is moved to the side farther from the rectilinear command position. It is characterized by being configured as described above.

  That is, in the first turning state, the turning radius is increased by increasing the amount of deceleration when the traveling speed of the turning side traveling device is decelerated from the traveling speed of the other traveling device as the turning operation tool moves away from the rectilinear command position. In the second turning state, the turning speed of the turning-side traveling device becomes 0, so that the turning radius is further reduced. In the third turning state, the turning-side traveling device is moved in the traveling direction of the other traveling device. The turning radius is further reduced by increasing the traveling speed of the turning-side traveling device at that time as the turning operation tool is moved away from the straight-ahead command position.

  Therefore, it is possible to change from a gentle turning state to a small turning state, and a suitable means for carrying out claim 3 can be obtained.

  According to a fifth characteristic configuration of the present invention, in addition to the first or second characteristic configuration, the turning command means is arranged so that the straight turn command position for directing the straight advance is positioned adjacent to the straight advance command position and the left turn A left turn command range and a right turn command range for commanding a right turn adjacent to the straight advance command position, and the left turn command range. And in each of the right turn command ranges, the greater the amount of movement in the direction away from the straight advance command position, the larger the turn state is commanded, and the speed control means includes the left turn command range and the left turn command range. In each of the right turn command ranges, the turn with respect to the change per unit of the operation position of the turn command means in the small side operation range in which the movement amount of the turn command means in the direction away from the straight advance command position is small. As the amount of change in the insensitive turning state is small, and the amount of movement in the direction away from the rectilinear command position is large, the operation range per unit of the operation position of the turn command means is increased. Based on the command information of the turning command means, the target turning force is obtained in a form that makes a sensitive turning state in which the change amount of the turning force with respect to the change is larger than the change amount of the turning force in the small operation range. Thus, the linearly variable continuously variable transmission and the continuously variable continuously variable transmission are configured to perform a shift operation so as to achieve the target turning force.

  That is, when the turning command means is moved within the small side operation range to change and adjust the turning force, the insensitive operation state is entered and the target turning with respect to the change per unit amount of the operation position of the turning command means The amount of force change is small. Then, when moving beyond the small-side operation range to the large-side operation region, the amount of change in the target turning force increases with respect to the change in the operation position. Even if the target turning force in the state operated to the maximum operation position with the largest movement amount in the direction away from the command position is set to a large one capable of making a sudden turn, for example, within the large side operation range. There is no need to unnecessarily widen the moving operation range of the turn command means.

  Therefore, it is possible to obtain a large turning force when operated to the maximum operating position without unnecessarily widening the moving operation range of the turning command means, but fine adjustment is performed when operating to the small operation range. Thus, it is possible to perform a gentle turn while performing the above, and a suitable means for carrying out claim 1 or 2 is obtained.

  In addition to the fifth feature configuration described above, the sixth feature configuration of the present invention is configured to be in the insensitive operation state in the small side operation range and in the sensitive operation state in the large side operation range. And a turning force setting means for setting a correlation between the operation position of the means and the target turning force, and capable of changing the correlation based on an artificial operation command. The speed control means includes the turning force. Based on the command information of the command means and the setting information of the turning force setting means, the linearly variable continuously variable transmission and the swing continuously variable transmission are operated so as to achieve the target turning force. Features a point.

  That is, the turning force setting means for setting the correlation between the operation position of the turning command means and the target turning force is configured to change and set the correlation based on the artificial operation command. It is possible to change the correlation to an appropriate correlation according to the working status of the worker and the skill level of the worker.

  Therefore, it is possible to set the target turning force with respect to the operation position of the turn command means in an appropriate state according to the difference in the work situation at that time, the difference in the level of proficiency with respect to the turn operation of the operator, and the like. Thus, means suitable for carrying out the present invention can be obtained.

  According to a seventh characteristic configuration of the present invention, in addition to the first or second characteristic configuration, the turning command means is arranged so that the straight turn command position for directing the straight advance and the left turn when the straight turn command position is adjacent to the straight advance command position. A left turn command range and a right turn command range for commanding a right turn adjacent to the straight advance command position, and the left turn command range. And in each of the right turn command range, a larger turn state is commanded as the amount of movement in a direction away from the straight travel command position is larger, and the left turn command range and the right turn command range In each of the above, the turning operation of the turning instruction means is performed in a state where the turning force is increased or decreased when the turning command means is operated to the maximum operation position in which the movement amount in the direction away from the rectilinear instruction position is maximum. To range An artificially operated turning force change setting means capable of setting and changing the correlation between the operation position and the target turning force is provided, and the speed control means includes command information of the turning command means and the turning force change setting. Based on the setting information of the means, the target turning force determined by the correlation set by the turning force change setting means and the operation position in the turning command range of the turning command means The present invention is characterized in that the linearly variable continuously variable transmission device and the turning continuously variable transmission device are configured to perform a speed change operation.

  That is, the operator manually operates the turning force changing force setting means according to the skill level of the operator and the working situation at that time before operating the turning command means to perform the turning operation. The correlation between the operation position and the target turning force is changed and set. In the change setting, the turning force when the turning command means is operated to the maximum operation position where the movement amount is the largest in the turning command range is increased or decreased.

  Therefore, the turning force when the operator feels that a large turning force is necessary and the turning command means is operated to the maximum operation position is set to change the people as appropriate by the operator in the turning force change setting means. Therefore, the turning operation can be performed with an appropriate turning force, and a suitable means for implementing the first or second aspect can be obtained.

  According to an eighth characteristic configuration of the present invention, in addition to the first to seventh characteristic configurations described above, the speed change of the geared object for shifting in each of the continuously variable continuously variable transmission device and the continuously variable transmission device for turning. A pair of shift position detecting means for detecting a position; a pair of shift output detecting means for detecting an output rotation speed in each of the linearly variable continuously variable transmission and the turning continuously variable transmission; and And a target rotational speed command means for commanding a target rotational speed of each of the continuously variable transmission and the continuously variable transmission for turning, and the speed control means in each of the straight-ahead control processing and the turning control processing The reference information set for obtaining the target shift position of the gear to be operated corresponding to the rotational speed to be output for each of the linearly variable continuously variable transmission and the continuously variable continuously variable transmission. Based on output A target shift position of the gear-operated object corresponding to the rotational speed is obtained, and the gear shift is performed such that a detection value of each of the pair of gear-shift position detecting means becomes a target gear shift position of the gear-operated object. And switching between a traveling control mode for executing traveling control and a calibration processing mode for executing calibration processing for detection values of each of the pair of shift position detecting means. As the calibration process in the calibration process mode, the straight-running continuously variable transmission and the turning continuously variable transmission are each linearly driven based on the detection value of the shift output detecting means. Each of the continuously variable transmission device and the continuously variable transmission device for turning is operated so as to be in the reference rotation state, and the continuously variable transmission device in the reference rotation state is operated. Based on the detected value of the corresponding speed change position detection means, and said points to calibrate the reference information about them shift position detecting means.

  That is, the correlation between the target rotational speed commanded by the target rotational speed command unit and the shift position of the operated body is performed by switching the speed control unit to the calibration processing mode and executing the calibration process on the detected value. The reference information, which is information indicating the shift position detection means, is configured in an appropriate state corresponding to the actual detection value by the shift position detection means, so that left and right shift position detection caused by detection errors and assembly errors of the shift position detection means The shift of the actual shift position of the means can be suppressed, and the target shift position corresponding to the target rotational speed can be set accurately.

  Therefore, even when there is a detection operation by the shift position detecting means or an assembly error, it is possible to accurately set the target shift position corresponding to the target rotational speed, which is suitable for implementing claims 1 to 7. Means are obtained.

[First embodiment]
Hereinafter, the case where the control valve and the shift operation device according to the present invention are applied to a shift operation device in a combine will be described with reference to the drawings.

  FIG. 1 shows an overall side view of a combine that is an example of a work vehicle. The combine is set at the front of a traveling machine body 2 that is driven by a pair of left and right crawler type traveling devices 1R and 1L. A threshing device 4 that cuts the straw and conveys it backwards is connected so as to be able to move up and down, and the threshing device 4 that receives the harvested cereal mash from the cutting and transportation device 3 and performs threshing / sorting processing to the traveling body 2 It is comprised by mounting the grain tank 5 which stores the grain from the apparatus 4, and forming the boarding operation part 6 in the front location of the grain tank 5. FIG.

Next, the transmission structure of this combine is demonstrated.
As shown in FIG. 2, the continuously variable transmission 7 for linear travel that can change the traveling speed in a straight traveling state and the traveling speed of the traveling device that is located on the turning center side during turning traveling can be varied for turning. Of the continuously variable transmission 8 and a transmission case 9 to which the power from the continuously variable transmissions 7 and 8 is input and the power to the left and right traveling devices 1R and 1L is output. Has been.

  The linearly variable continuously variable transmission 7 and the continuously variable continuously variable transmission 8 include variable hydraulic pumps 7A and 8A driven by power from an engine mounted on a combine body, and variable hydraulic pumps 7A, 7A, It is constituted by a hydrostatic continuously variable transmission (HST) having a well-known structure constituted by a pair with hydraulic motors 7B and 8B that are rotationally driven by oil supplied from 8A. Incidentally, the power of the engine is transmitted to the transmission shaft 12 of the variable hydraulic pumps 7A and 8A via the transmission belt 10 and the transmission pulley 11.

  The transmission case 9 includes therein an output shaft 20 of the continuously variable transmission 7 for linear movement and an output shaft 21 of the continuously variable transmission 8 for turning. Power from 20, 21 is transmitted to the pair of left and right traveling devices 1R, 1L, while power from the output shaft 20 of the continuously variable continuously variable transmission 7 is transmitted to the cutting and conveying device 3. . A right output gear 21a and a left output gear 21b are fixed to the output shaft 21 of the continuously variable transmission 8 for turning.

  A pair of large and small output gears 20a, 20b for sub-shifting and an output gear 20c for driving the cutting unit are fixed to the output shaft 20 of the continuously variable transmission 7 for linear movement. The auxiliary transmission shaft 22 supports an auxiliary transmission small-diameter gear 22a and a large-diameter gear 22b that are always meshed with the output gears 20a and 20b, and is relatively rotatably supported. A sub-shift gear shift gear 22d that rotates integrally with the transmission shaft 22 is slidably fitted in the axial direction. A sub-transmission device is configured in which the sub-shift gear 22d is slid and operated so that it can be shifted in two steps. An output gear 22e is fixed to the auxiliary transmission shaft 22, and a center gear 24 provided integrally with the support shaft 23 is always in mesh with the output gear 22e.

  The support shaft 23 has a straight transmission state in which the speed change output of the continuously variable transmission 7 for straight travel is transmitted to each of the pair of left and right traveling devices 1L and 1R on both sides of the center gear 24, and the straight travel A left-turn transmission state in which the shift output of the continuously variable transmission is transmitted to the right traveling device and the shift output of the continuously variable transmission for turning is transmitted to the left traveling device, the shift of the continuously variable continuously variable transmission There is provided a transmission state switching means 27 that can switch to a right-turning transmission state that transmits an output to the left-side traveling device and transmits a shift output of the continuously variable transmission for turning to the right-side traveling device.

  The transmission state switching means 27 includes a left and right outer gear portion 25a that is always meshed with the left output gear 21a, and a right gear device that has a right outer gear portion 25b that is always meshed with the right output gear 21b. A pair of left and right meshing clutches 27, 27 formed between a pair of multi-plate friction clutches 25, 25 (an example of a friction-type turning clutch) and both side surfaces of the center gear 24 and the shift gear 26 facing the side gears. It consists of and. The left friction clutch 25 constitutes a left clutch that can be switched to a state in which transmission between the continuously variable transmission 8 for turning and the left traveling device 1L is cut off, and the right friction clutch 25 A right clutch that can be switched to a state in which the transmission between the continuously variable transmission 8 for turning and the right traveling device 1R is cut off is configured.

  The left and right shift gears 26 can be shifted in the direction of the axis of rotation, and when the shift operation is performed, the meshing clutch 27 meshes with the transmission and the meshing clutch 27 enters a state where transmission is not engaged. The friction plate in the shift gear 26 is configured to be shiftable with respect to the main body of the shift gear 26. When the clutch 27 is in a transmission cut-off state, the multi-plate friction clutch 25 is in pressure contact and is transmitted. It is configured to be switchable between a state where it is engaged and a state where transmission where the multi-plate friction clutch 25 is not pressed is cut off.

  That is, the power transmission to the pair of left and right traveling devices 1L, 1R is a transmission state in which the power from the straight transmission 7 is transmitted and the friction clutch 25 is in pressure contact in the transmission state in which the meshing clutch 27 is engaged. Then, when the power from the turning continuously variable transmission 8 is transmitted and both the meshing clutch 27 and the friction clutch 25 are in the transmission cut-off state, the continuously variable transmission 7 for straight traveling and the continuously variable transmission for turning. No power is transmitted from either of them.

  The left and right shift gears 26, 26 are urged to a transmission state in which the mesh clutches 27, 27 mesh with each other by the pressing force of the pressure springs 29, 29, respectively. By shifting the hydraulic cylinders 31L and 31R for shutting off against the pressing force of the clutch 29, the switching operation can be switched to the transmission cut-off state where the meshing clutches 27 and 27 are not engaged. The operation of the shutoff hydraulic cylinders 31L and 31R is configured by switching the shutoff solenoid valves 63 and 64 as shown in FIG. In this transmission cut-off state, the friction plate in the shift gear 26 is shifted by the steering hydraulic cylinders 30L and 30R, so that the operation can be switched to the transmission state in which the friction clutches 25 and 25 are pressed. The shift gear 26 is transmitted to the pair of left and right traveling devices via the final gear 35. The shift gear 26 is configured to always mesh with the relay gear 34 of the transmission system to the traveling device regardless of whether the meshing clutch 27 is meshed or not.

  The linearly variable continuously variable transmission device 7 is configured to be able to perform a stepless speed change operation from the neutral position in each of the forward rotation direction and the reverse rotation direction. A manually operated shift operation tool 14 (an example of speed command means) for operating the device 7 is provided. The shift operation tool 14 is manually swung over a predetermined front / rear operation range along the front / rear direction. It is configured to be movable. As shown in FIG. 3, the straight traveling swash plate 13 of the variable hydraulic pump 7 </ b> A is linked to the speed change operation tool 14 via a hydraulic servo mechanism SV (an example of servo means), and based on an operation command of the speed change operation tool 14. By changing the angle of the straight traveling swash plate 13 (an example of the object to be operated), the output state on the hydraulic motor 7B side is changed steplessly. That is, if there is a manual operation on the speed change operation tool 14, the speed change operation can be lightly operated by performing an assist operation with a hydraulic operation force by the action of the hydraulic servo mechanism SV. .

  Then, as shown in FIG. 5, when the shift operation tool 14 is in the neutral range and the neutral state is commanded, the straight traveling swash plate 13 becomes neutral, and the hydraulic motor 7B does not rotate and is maintained in the stopped state. If the command from the speed change operation tool 14 is a speed change command to the forward speed increase side or the reverse speed increase side, the angle of the straight traveling swash plate 13 is rotated forward by the hydraulic servomechanism SV according to the operation command of the speed change operation tool 14. The hydraulic motor 7B is tilted in the direction (forward acceleration direction) or in the reverse direction (reverse acceleration direction) by the hydraulic operation force by the command amount by the shift operation tool 14, and the hydraulic motor 7B is rotated in the forward direction or the reverse direction at a speed according to the command. The gears are operated so as to be rotationally driven.

  On the other hand, like the continuously variable continuously variable transmission 7 for the turning, the continuously variable transmission 8 for turning is configured to be capable of a variable speed operation in both the forward direction and the reverse direction. However, the turning continuously variable transmission 8 does not perform shifting manually, but the turning swash plate 15 (an example of an object to be operated) of the variable hydraulic pump 8A is a hydraulic turning operation mechanism 16 (shifting). An example of the control means is configured to change the output state on the hydraulic motor 8B side by changing the swash plate angle by the turning operation mechanism 16. As shown in FIG. 3, the turning operation mechanism 16 includes a double-acting shift hydraulic cylinder 17 (an example of a shift actuator) coupled to a turning swash plate 15 in a continuously variable transmission 8 for turning. The hydraulic control unit VU is configured to switch the hydraulic oil supply / discharge state for the transmission hydraulic cylinder 17. The shifting hydraulic cylinder 17 is configured as a double-acting type that can be operated from the neutral position in the forward direction and in the reverse direction, and is urged to return to the neutral position by the urging force of the pair of left and right springs 17a and 17b. It becomes the composition which is done.

Next, the configuration of the hydraulic control unit VU will be described.
As shown in FIG. 4, the hydraulic control unit VU includes a hydraulic pilot control valve 36 that controls the hydraulic pressure supply state so as to drive the shift hydraulic cylinder 17 in the forward and reverse directions from the neutral shift position. It is configured. The control valve 36 includes a spool 37 that can be moved to a forward output position moved in the forward direction from the neutral position, and a reverse output position moved in the reverse direction from the neutral position, and the spool 37 is moved to the neutral position. And a pair of coil springs 38 and 39 as urging means for urging and returning to the pilot oil passage, and a relief valve 49 for the pilot oil passage.

  Further, the control valve 36 is supplied with hydraulic oil for moving the spool 37 in the forward direction and is supplied with hydraulic oil for moving the spool 37 in the reverse direction. A reverse pressure operation section 41 to be supplied is provided, and a forward pressure solenoid valve 42 for pilot pressure control for controlling the supply state of hydraulic oil to the forward pressure operation section 40, and a reverse pressure operation section 41. A reverse pressure solenoid valve 43 for pilot pressure control that controls the supply state of hydraulic fluid to the engine is switchable between a supply state for supplying hydraulic fluid and a discharge state for discharging hydraulic fluid, and is urged to return to the discharge state. It is provided in the state.

  That is, the pair of pilot pressure control solenoid valves 42 and 43 stop supplying the hydraulic oil supplied from a hydraulic pump (not shown) to the pressure operating units 40 and 41 and the supply from the hydraulic pump. Thus, the solenoid valves 42 and 43 for controlling the pilot pressure are springs. It is configured to be urged to return to the discharge state by 45 and 46, and by energizing and energizing the solenoids 47 and 48, the valve body is operated against the urging force of the springs 45 and 46 to enter the supply state. It is configured to switch. Therefore, when the energization is stopped, the pilot pressure control solenoid valves 42 and 43 are always in the discharged state, and the state is maintained.

  The control valve 36 is provided with a pair of output ports OP1 and OP2 that are individually connected to the pair of hydraulic oil chambers 17A and 17B of the hydraulic cylinder 17 for speed change. In the neutral position as shown in FIG. Each of the pair of output ports OP1 and OP2 is configured not to be connected to either the input port IP or the discharge port DP. Therefore, the shift hydraulic cylinder 17 is in a state of maintaining the shift position at that time.

  When the spool 37 reaches the forward output position, one forward output port OP1 connected to the hydraulic fluid chamber 17A for forward operation of the shifting hydraulic cylinder 17 out of the pair of output ports OP1 and OP2. Is connected to the input port IP, and the reverse output port OP2 connected to the hydraulic oil chamber 17B for reverse operation of the shifting hydraulic cylinder 17 is connected to the discharge port DP. Therefore, the shifting hydraulic cylinder 17 is moved in the forward direction (forward acceleration direction).

  When the spool 37 reaches the reverse output position, the forward output port OP1 is connected to the discharge port DP, and the reverse output port OP2 is connected to the input port IP. Therefore, the shifting hydraulic cylinder 17 is operated to move in the reverse direction (reverse acceleration direction).

  When the shift operation of the continuously variable transmissions 7 and 8 as described above is described, for example, as shown in FIG. 5, the neutral position where the shift positions of the swash plates 13 and 15 have a predetermined width including the command position N for straight travel In this case, the shift output (travel speed) becomes zero, and when the shift position of the swash plates 13 and 15 is rotated in a predetermined direction from the neutral range, the travel speed in the forward direction is increased steplessly. When the swash plates 13 and 15 are operated in a direction opposite to the predetermined direction from the neutral zone, the traveling speed in the reverse direction is increased steplessly.

  The boarding operation unit 6 commands the rectilinear command position for commanding the rectilinear movement, commands the left turn adjacent to the rectilinear command position, and moves within a set range in the perspective direction with respect to the rectilinear command position. A left turn command range in which a lower target speed is commanded as the distance from the straight travel command position is set, and a right turn command is commanded adjacent to the straight travel command position, and a setting range is set in a perspective direction with respect to the straight travel command position. A turning lever 56 (an example of a turning command means) is provided that can be moved and operated over a right turning command range in which a lower target speed is commanded as it moves away from the straight advance command position. As shown in FIG. 3, a turning lever sensor 57 (an example of operation position detecting means) comprising a rotary potentiometer that detects the operation position of the turning lever 56, and the output rotation speeds of the pair of continuously variable transmissions 7 and 8, respectively. Are detected by counting the number of teeth of the output gear 22e and the right output gear 21a. The rotation sensors 58 and 59 (an example of speed detecting means) and the slant of the straight traveling swash plate 13 of the continuously variable transmission 7 for straight traveling. A potentiometer type linear shift position sensor 60 for detecting the plate angle (an example of the shift position detecting means), and a potentiometer type shift position sensor 61 for turning that detects the swash plate angle of the continuously variable transmission 8 for turning. An example of position detecting means), a turning mode switching operation tool 62 and the like for switching the turning mode to three stages by dial operation are provided. Control device H (an example of speed control means and travel state switching control means) for controlling the operation of the control mechanism 16 and the steering hydraulic cylinders 30R and 30L and the cutoff hydraulic cylinders 30R and 31L. ing.

  The straight shift position sensor 60 outputs a voltage corresponding to the angle (tilt position) of the straight travel swash plate 13 in the straight shift device 7, and the voltage is A / D converted for straight travel. The detected shift value is input to the control device H, and the turning shift position sensor 61 outputs a voltage corresponding to the angle (tilting position) of the turning swash plate 15 in the turning continuous transmission 8. The voltage is A / D converted and input to the control device H as a detected value for turning.

  Next, the traveling control by the control device H will be described. As shown in the flowchart of FIG. 6, when the turning lever 56 is in the neutral position, the traveling control processing for straight traveling is executed. (Step 5). In other words, the continuously variable transmission 7 for linear movement is subjected to a shift operation so that the traveling speed instructed by the transmission operation tool 14 is achieved, and the continuously variable transmission 8 for turning is continuously changed to the continuously variable transmission for linear movement. 7 is configured to execute a straight-ahead control process in which a speed change operation is performed so as to be the same as the speed detected by the rotation sensors 58 and 59 for detecting the speed 7.

  At this time, the shift operation speed for shifting the continuously variable transmission 8 for turning so as to be the same as the detection speed of the rotation sensors 58 and 59 is set to the traveling speed commanded by the shift operation tool 14. The continuously variable transmission 8 for turning is configured to perform a shift operation in a state where the speed is higher than the speed change operation speed at which the continuously variable continuously variable transmission 7 is operated.

  When the turning lever 56 is turned to the left or right from the neutral position, the traveling state switching control means operates the hydraulic cylinder 31R on the right side and turns the right side when the turning center side, that is, the turning direction is right. The right hydraulic cylinder 30R is actuated to switch to the right turning transmission state in which the shifting power of the continuously variable transmission 8 for turning is transmitted to the right traveling device 1R (steps 1 to 3). Is the left turning hydraulic cylinder 31L and the left steering hydraulic cylinder 30L is actuated to transmit the shifting power of the continuously variable transmission 8 for turning to the left traveling apparatus 1R. (Step 4).

  Then, the left and right traveling devices 1R and 1L have the same rotational direction, and the speed ratio of those rotational speeds is the speed ratio corresponding to the turning radius commanded by the turning lever 56. A turn control process for obtaining a target shift position of the transmission is configured to be executed.

  The processing for obtaining the target shift position will be described. As shown in FIG. 8, the relationship between the amount of movement of the turning lever 56 in the turning command operation area in the direction away from the rectilinear command position and the speed ratio corresponding to the turning radius is shown. It is determined and stored as a relationship corresponding to a quadratic function. On the other hand, the target shift position of the continuously variable transmission 8 for turning, that is, the target swash plate position, is obtained from the detected value for straight travel from the straight shift position sensor 60 and a function having a relationship as shown in FIG. . Then, the shift operation is performed by controlling the operation of the turning operation mechanism 16 so that the detected value for turning from the turning position sensor 61 for turning becomes the target shift value. Incidentally, the speed change position of the continuously variable transmission 7 for straight traveling is adjusted by manual operation with respect to the speed change lever 14.

  Referring to FIG. 7, the line L1 in FIG. 7 shows the speed of the reference continuously variable transmission, the line L2 shows the change in the target rotational speed in the slow turning mode, and the line L3 shows the signal. A change in the target rotation speed in the ground turning mode is shown, and a line L4 shows a change in the target rotation speed in the super turning mode, and the turning mode designated by the turning mode switching operation tool 62 is selected. become. In other words, in the gentle turning mode indicated by the line L2, when the turning lever 56 is operated to the maximum operating position, the turning side traveling device is about 1/3 of the traveling speed V of the opposite side traveling device. A change characteristic of the speed ratio of the left and right traveling apparatuses 1R and 1L with respect to the operation position of the turning lever 56 is set in advance so as to be decelerated to the speed. In the belief turning mode indicated by the line L3, when the turning lever 56 is operated to the maximum operating position, the operation position of the turning lever 56 is decelerated until the traveling speed of the turning side traveling device becomes zero. The speed ratio of the left and right traveling devices 1R, 1L is preset. Also, in the super turning mode indicated by the line L4, when the turning lever 56 is operated to the maximum operating position, the running speed of the turning side traveling device rotates in the opposite direction to the drive rotation direction of the opposite side traveling device. The speed ratio of the left and right traveling apparatuses 1R and 1L with respect to the operation position of the turning lever 56 is set in advance so that the speed is the same as the speed of the opposite traveling apparatus.

  A process for controlling the operation of the turning operation mechanism 16 when the turning continuously variable transmission 8 is shifted will be described. For example, when the continuously variable transmission 8 for turning is shifted in the forward acceleration direction in accordance with the operation of the turning lever 56, the spool 37 in the control valve 36 is moved to the forward output position. Specifically, a pulse current that repeatedly turns on and off is supplied to the solenoid 47 in the solenoid valve 42 for pilot pressure control with respect to the pressure operation unit 40 for forward rotation every setting cycle, and according to the duty ratio. Thus, the solenoid valve 42 is switched between a supply state and a discharge state. As a result, the spool 37 is operated to move against the biasing force of the spring 39 by the electromagnetic force, and moves to the forward output position. When shifting the continuously variable transmission 8 for turning in the reverse speed increasing direction, the spool 37 in the control valve 36 is moved to the reverse output position. At this time, the pilot pressure applied to the pressure operating unit 41 for reverse rotation is operated. The control solenoid valve 43 is similarly controlled.

  When the output rotational speed of the continuously variable transmission 8 for turning reaches the target rotational speed by the speed increasing operation, the spool 37 is moved to the neutral position. As a result, the hydraulic oil is not discharged from the transmission hydraulic cylinder 17, and the transmission hydraulic cylinder 17 maintains the transmission position at that time. Note that the same processing is performed for the operation at the forward holding position even when the holding is performed at the backward holding position.

[Second Embodiment]
Hereinafter, the second embodiment of the turning control device for a work vehicle according to the present invention will be described. However, the basic configuration is the same as that of the first embodiment, and therefore the same configuration is described in the first embodiment. The same reference numerals as those of the embodiment are attached, and the description is omitted.

  As shown in FIG. 8, a three-contact mode changeover switch 71 for switching three different types of turning modes to a slow turning mode, a trust turning mode, and a super turning mode, A turning state setting unit 72 is provided as a turning operation mode change setting means that can artificially change the relationship between the operation position of the turning lever in the ground turning mode and the target turning state.

  The processing for obtaining the target shift position will be described. As shown in FIG. 9, the line L1 in FIG. 9 indicates the speed of the straight-line continuously variable transmission on the basis, and the line L2 indicates the target rotation in the slow turning mode. A change in speed is indicated, line L3 indicates a change in target rotational speed in the pivot turn mode, and line L4 indicates a change in target rotational speed in the super pivot turn mode, which is designated by the turn mode changeover switch 71. The selected turning mode is selected. In other words, in the gentle turning mode indicated by the line L2, when the turning lever 56 is operated to the maximum operating position, the turning side traveling device is about 1/3 of the traveling speed V of the opposite side traveling device. A change characteristic of the speed ratio of the left and right traveling apparatuses 1R and 1L with respect to the operation position of the turning lever 56 is set in advance so as to be decelerated to the speed. In the belief turning mode indicated by the line L3, when the turning lever 56 is operated to the maximum operating position, the operation position of the turning lever 56 is decelerated until the traveling speed of the turning side traveling device becomes zero. The speed ratio of the left and right traveling devices 1R, 1L is preset. Also, in the super turning mode indicated by the line L4, when the turning lever 56 is operated to the maximum operating position, the running speed of the turning side traveling device rotates in the opposite direction to the drive rotation direction of the opposite side traveling device. The speed ratio of the left and right traveling devices 1R, 1L with respect to the operating position of the turning lever 56 is preset so that the speed is reduced to about 1/3 of the traveling speed V of the opposite traveling device in the direction. .

  As shown in FIG. 10, the turning state setting device 72 maintains the change in the deceleration amount of the traveling speed of the crawler traveling device on the turning side with respect to the operation amount of the turning lever 56 by the adjustment volume or the like while maintaining the linear state. The operation position (point P in FIG. 10) of the turning lever 56 at the time of the state can be changed and adjusted to an arbitrary position, and the crawler on the turning side with respect to the operation amount of the turning lever 56 The change in the amount of deceleration of the traveling speed of the traveling device can be switched from the linear state to the arc state as shown in FIG.

[Third Embodiment]
Hereinafter, a third embodiment of the turning control device for a work vehicle according to the present invention will be described. Since the basic configuration is the same as that of the first embodiment, the same configuration is described in the first embodiment. The same reference numerals as those of the embodiment are attached, and the description is omitted.

  As shown in FIG. 12, three different turning modes can be switched to a gentle turning mode, a belief turning mode, and a super turning turn mode, and the operation position of the turning lever 56 in the small-side operation range W1 can be changed. A three-contact mode changeover switch 71 configured to increase / decrease the amount of change in the target turning force with respect to the change per unit amount and the width of the operation region in the small-side operation range W1, and Two potentiometer-type artificial operation-type adjustment operation tools 73a and 73b are provided.

  The processing for obtaining the target shift position will be described. As shown in FIG. 13, the line L1 indicates the speed of the reference continuously variable transmission on the straight side, and the line L2 indicates the change in the target rotation speed in the slow turning mode. The line L3 indicates the change in the target rotation speed in the belief turn mode, and the line L4 indicates the change in the target rotation speed in the super belief turn mode. The turn mode designated by the mode changeover switch 71 is shown in FIG. Will be selected. However, the correlation of the small operation range W1 does not change even when the mode changeover switch is changed over. When the adjustment operation tool 73a for adjusting the deceleration amount is operated, the end point position (point P in FIG. 13) of the small side operation range W1 can be moved and adjusted in the vehicle speed increasing / decreasing direction (Y direction), and the operation width can be changed. When the adjustment operation tool 73b is operated, the end point position (point P in FIG. 13) of the small operation range W1 can be moved and adjusted in the operation position changing direction (X direction).

  Each line shown in FIG. 14 is different from FIG. 13 in that the small-side operation range W1 is set in a state having a constant interval in the vehicle speed increasing / decreasing direction (Y direction) by switching the mode changeover switch. The correlation is changed.

  As shown in FIG. 15, in the small-side operation range W1 and the large-side operation range W2, exceptionally different lines are formed for each mode, and the small-side operation range W1, the large-side operation range W2, and the joints thereof are formed. Over the entire range including the portion, as the amount of movement of the turning lever 56 increases, it changes smoothly while drawing a quadratic curve in a form that gradually changes with respect to the change per unit amount of the operating position of the turning lever 56. It is configured to go.

[Fourth embodiment]
Hereinafter, the fourth embodiment of the turning control device for a work vehicle according to the present invention will be described. The basic configuration is the same as that of the first embodiment, and therefore the same configuration is described in the first embodiment. The same reference numerals as those of the embodiment are attached, and the description is omitted.

  As shown in FIG. 16, as the turning force setting means 74, an area selection switch 74a and an adjustment operation tool 74b are provided.

  The processing for obtaining the target shift position will be described. As shown in FIG. 17, the entire range L1 is changed and adjusted to change the turning force when the turning lever 56 is operated to the maximum operating position. It is configured to be adjustable from the speed difference zero state shown to the maximum speed difference setting state shown in the line L5, and such characteristics are set in advance, and the entire range that can be changed and adjusted is divided into three regions A, B, The area is switched by a three-contact area selection switch 74 that is divided into C and switches to any one of the areas A, B, and C. The adjustment operation tool 74b is configured to be able to change and adjust the turning force when operated to the maximum operation position in the region selected by the region selection switch 74.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the turning control device for a work vehicle according to the present invention will be described. Since the basic configuration is the same as that of the first embodiment, the same configuration is described in the first embodiment. The same reference numerals as those of the embodiment are attached, and the description is omitted.
As shown in FIG. 18, a shift lever sensor 82 for detecting the operation position of the shift operation tool 14 and a swing lever sensor 57 for detecting the operation position of the swing lever 56 are provided, both of which are provided in a rotary potentiometer. Configured.

  The shift operation tool 14 and the shift lever sensor 82 can be freely moved within a predetermined operation range including a stop command position for instructing to stop traveling, and the amount of movement operation from the stop command position becomes larger in a straight traveling state. Vehicle speed command means S1 for commanding a target vehicle speed is configured, and the turn lever 56 and the turn lever sensor 57 can be changed between a straight advance command state for moving the vehicle straight and a turn command state for turning the vehicle body, and the turn command. In the state, turning state command means S2 for instructing the turning direction and turning radius of the vehicle body is configured.

  The continuously variable transmissions 7 and 8 for straight traveling and turning include linear speed and turning rotational speed sensors 83 and 84 as speed change output detecting means for detecting their output rotational speeds separately, and for straight traveling Further, the shift position sensor 60 for straight and turning as a shift position detecting means for detecting the operation position of the swash plates 13 and 15 for straight traveling and turning, that is, the shifting position of the continuously variable transmissions 7 and 8 for turning. , 61 are provided.

  A control device H using a microcomputer for controlling the operation of the hydraulic cylinders 17 and 81 is provided. The control device H is used for straight traveling and turning based on detection information of the shift lever sensor 82 and the turning lever sensor 57. Processing for calculating the target rotational speeds of the continuously variable transmissions 7 and 8 for the vehicle, and setting the target shift positions corresponding to the obtained target rotational speeds, the shift position sensors 60 for straight travel and turning, The running control is performed to control the operation of each hydraulic cylinder 17 and 81 so that the detected value 61 becomes the target shift position.

  Therefore, by using the control device H, based on the respective command information of the vehicle speed command means S1 and the turning state command means S2, the continuously variable for straight running and turning so as to correspond to the commanded traveling state The calculation means 100 which calculates | requires the target rotational speed of the transmissions 7 and 8 and the traveling control means 101 which performs the said traveling control are comprised. Further, the vehicle speed command means S1, the turning state command means S2, and the calculation means 100 constitute target rotation speed command means MO for instructing the respective target rotation speeds of the pair of continuously variable transmissions.

  In other words, the control device H is operated when the speed change operation tool 14 is operated to a neutral position that is located approximately in the middle of the operable range in a state in which the turning lever 56 is operated to the straight travel command position and the straight travel is commanded. When the travel is stopped and the swinging operation from the neutral position to the forward side is performed, the traveling speed to the forward side is increased steplessly, and when operated from the neutral position to the reverse side, the reverse side is accordingly accompanied. The vehicle speed is continuously increased so that the vehicle body travels straight at the target travel speed commanded at that position when the speed change operation tool 14 is fixed at a predetermined position. The operation of the hydraulic cylinder 81 is controlled.

  Then, the linearly variable continuously variable transmission device 7 is operated to change the speed to be instructed by the transmission operation tool 14, and the turning continuously variable transmission device 8 is converted to the linearly variable continuously variable transmission device 7. The speed change operation is performed so that the speed is the same as the speed.

  At this time, the speed change operation tool 14 instructs a speed change operation speed for changing the speed of the turning swash plate 15 of the turning continuously variable transmission 8 so that the speed is the same as that of the continuously variable continuously variable transmission 7. The turning continuously variable transmission 8 is shifted in a state in which the speed of the straight traveling swash plate 13 of the linearly variable continuously variable transmission 7 is set to be larger than the speed change operation speed for shifting. It is configured.

  Then, when the speed change operation tool 14 is operated and the control device H is traveling at a predetermined speed, if the turning lever 56 is swung from the straight command position to either the left or right turn command range, the straight device travels straight. The operation of each of the hydraulic cylinders 17 and 81 is controlled such that the turning radius becomes smaller as the operation is further away from the command position.

  First, the configuration of the turning command by the turning lever 56 will be described. When the turning travel is commanded, control is executed so that the turning lever 56 becomes a turning state in which the turning radius becomes smaller as the turning lever 56 is operated to the side away from the straight-ahead command position in the turning command range. The relationship between the operation position of the turning lever 56 in the turning command range and the target turning state when the turning operation is performed can be basically switched to three different turning modes. That is, a three-contact mode changeover switch 71 is provided for switching the above-described turning mode into three turning modes of a gentle turning mode, a trust turning mode, and a super turning mode. A switching command by the switch 71 is given to the control device H, and the control device H is configured to switch the turning mode based on the switching command.

  On the other hand, the characteristic of the change in the target vehicle speed with respect to the operation position of the speed change operation tool 14 is preset and stored, and the control device H is the characteristic of the speed ratio of the left and right traveling devices by the operation of the turning lever 56 as described above. Then, based on the target vehicle speed determined at the operation position of the speed change operation tool 14, a process for obtaining the target rotational speed of the continuously variable transmissions 7 and 8 for straight travel and turning is executed. Then, as shown in FIG. 20, it is obtained as described above based on the reference information set for obtaining the target shift positions of the straight traveling and turning swash plates 13 and 15 corresponding to each target rotational speed. The target shift positions of the straight traveling and turning swash plates 13 and 15 corresponding to the target rotational speed are respectively set, and the linear movement detected by the straight moving and turning shift position sensors 60 and 61 are detected. The corresponding hydraulic cylinders 17 and 81 are controlled so that the shift positions of the swash plates 13 and 15 for turning become the respective target shift positions. There are two characteristic lines in FIG. 20 that are calibrated based on the actual measurement values of the straight-forward and turning gear position sensors 60 and 61 and set individually for each. The detection value calibration process will be described in detail later.

  Hereinafter, based on the control flowchart, the control operation of the calibration process by the control device will be specifically described. The control device H is configured to be switchable between a normal control mode for executing traveling control and an adjustment mode for performing detection value calibration processing as its control mode, and a switching command switch (not shown) is turned on. The adjustment mode can be commanded by turning on the power. This change command switch cannot be operated by a normal user, and the normal control mode is commanded during normal use. .

  As the detection value calibration process, based on the detection information of the rotational speed sensors 83 and 84, for the straight travel and for the turn, the continuously variable transmissions 7 and 8 for the straight travel and the turn are in the reference rotational state. The hydraulic cylinders 17 and 81 are automatically actuated, and by the actuation, the linear movement and turning shift position sensors 60 when the straight and turning continuously variable transmissions are respectively in the reference rotation state. , 61 is used to calibrate the correlation (reference information) of the target shift position with respect to the target rotational speed as shown in FIG. In the detection value calibration process, as the reference rotation state, the straight-speed and turning continuously variable transmissions each have a maximum speed or a speed close to the maximum speed, and a zero speed or a speed close thereto. In each of the low-speed side reference rotation state that is the speed, the detection values of the shift position sensors 13 and 15 for straight travel and turning are obtained, and the reference information is calibrated based on the detection values of the respective states. Has been. Note that such detection value calibration processing is performed in the inspection process at the stage before shipment in the combine manufacturing process or when the shift position sensors 46 and 47 are broken and replaced with new ones. It is performed by a worker or a maintenance worker, and is not performed by a normal user who performs agricultural work.

  Hereinafter, a specific control operation in the adjustment mode will be described. As shown in FIG. 21, in the normal control mode, when there is a start command, the travel control is executed (steps 20, 21, 22, 23). Then, when the power is turned on with the changeover command switch turned on, the adjustment mode is set, and when a preset activation condition is satisfied, a detection value calibration process is executed (steps 24, 25, and 26). The start conditions are that the engine is started, the accelerator set value is operated to the maximum value, and that the subtransmission is switched to the neutral state. . Therefore, if these conditions are not satisfied, the control device H is not switched to the adjustment mode.

Next, a detection value calibration process for obtaining two detection values for calibrating the correlation when changing from the neutral position to the forward direction in one shift position sensor will be described as an example.
Such a process is executed a total of four times for each of the linear movement and turning gear position sensors 46 and 47 corresponding to the operations in the forward and backward directions. As shown in FIGS. 22 and 23, if the detected value (neutral value) of the neutral position in the target shift position sensor is not read, the value is read (steps 31 and 32). Incidentally, the swash plates 13 and 15 are always urged to return to the neutral position by the return urging force when the speed change operation is not performed. After reading the neutral value, the shift hydraulic cylinder 17 (or 81) is driven to automatically move the target swash plate 13 (or 15) in the forward direction at the maximum speed (step 33, 34).

  At that time, the change in output is monitored while the shift output is read by the rotation speed sensor 83 (or 84) every set unit time, and the shift detected by the rotation speed sensor 83 (or 84) is monitored. When a state in which the output does not change for 1 second is detected, it is determined that the value corresponds to the maximum mechanically displaceable position indicated by point P1 in FIG. Then, the hydraulic cylinder 17 (or 81) is driven to automatically move the swash plate 13 (or 15) in the reverse direction at the minimum speed (steps 35 and 36). At this time, it is detected whether or not the shift output is changing based on the detection value of the rotational speed sensor 83 (or 84), and the duty ratio of the pulses of the electromagnetic valves 42 and 43 of the hydraulic cylinder 17 (or 81) is determined. If it is determined that the shift is not performed because it is too small, the duty ratio is changed to a slightly larger value (steps 37 and 38). When the shift output (rotation speed) detected by the rotation speed sensor 83 (or 84) reaches the maximum output (maximum rotation speed) (point P2 in FIG. 19) in the shift adjustable range, the shift position sensor at that time The detected value of 60 (or 61) is read as the maximum output value (steps 39 and 40). This state corresponds to the high-speed side reference rotation state.

  Next, if the detection value (zero speed value) of the zero speed position in the shift position sensor 60 (or 61) has not been read (step 41), the swash plate 13 (or 15) is turned backward at the minimum speed. An operation for automatically moving is performed. At this time, if the detected value is equal to or greater than the set value and the difference to the zero speed position is large, the moving operation is performed at the maximum speed (steps 42, 43, and 44). Even at this time, based on the detection value of the rotational speed sensor 83 (or 84), it is detected whether or not the shift output is changing, and if it is determined that the shift is not performed because the duty ratio is too small, the duty is The ratio is changed to a slightly larger value (steps 45 and 46). When zero speed is detected as the shift output (rotation speed) detected by the rotation speed sensor (at point P3 in FIG. 19), the detection value of the shift position sensor 60 (or 61) at that time is set to zero. It reads as a speed value and ends the processing (steps 47 and 48). This reading state of the zero speed value corresponds to the low speed side reference rotation state.

  Then, the reference information is calibrated to an appropriate value so as to correspond to the detected values of the two points (P2, P3) thus detected, and the reference information is stored. Note that the value of the intermediate position between the two points is defined by linear interpolation. Such processing is executed four times for each of the shift position sensors 60 and 61 in correspondence with the operations in the forward direction and the reverse direction, respectively. FIG. 20 shows two lines L1 and L2. As shown in FIG. 5, the calibration information is set as different calibration information for the pair of left and right shift position sensors 60 and 61 in correspondence with the respective different actual detection values, and these are stored.

[Another embodiment]
(1) Among the above-described embodiments, in the first to fourth embodiments, the speed control means includes a mechanical servo means and a speed change control means for operating the speed change actuator to change the speed. However, the speed control unit may be configured to include a shift control unit that operates two shift actuators to perform a shift operation. In such a case, the continuously variable transmission 8 for turning is changed to a speed commanded by the speed change operation tool 14, and the continuously variable continuously variable transmission 7 is used for turning You may comprise so that gear shifting operation may be carried out so that it may become the same speed as the speed of the step transmission 8. FIG.

(2) Of the above-described embodiments, in the fifth embodiment, the continuously variable transmission 7 for linear movement is operated to change to a speed commanded by the transmission operation tool 14 and the no-turning device is used. The step-variable transmission device 8 is configured to perform a speed change operation so as to have the same speed as that of the continuously variable continuously variable transmission device 7, but as described above, the turning continuously variable transmission device 8 is shifted. A speed change operation is performed so that the speed is commanded by the operation tool 14, and the linearly variable continuously variable transmission device 7 is operated so as to have the same speed as that of the continuously variable transmission device 8 for turning. You may comprise.

(3) In the above-described embodiment, the control valve is configured as a hydraulic pilot operation type in which the spool is moved by the pilot hydraulic pressure, and the working fluid is provided in the forward pressure operation portion and the reverse pressure operation portion. However, it is not limited to supplying hydraulic oil, but may be operated using other fluids such as those operated by air pressure. The spool is not limited to the one used, and the spool may be moved by electromagnetic force using a solenoid or the like.

(4) In the above embodiment, the amount of movement of the turning lever is detected by the potentiometer, and the turning continuously variable transmission is operated steplessly as the turning lever is operated. Not only in such a configuration, for example, a command to detect the displacement of the amount of movement of the turning lever step by step with a plurality of switches, or to change the turning radius depending on the time of pressing the turn command switch. You may implement in various forms, such as a structure to do.

(5) In the above embodiment, the control valve is applied to a speed change operation device that performs a speed change operation on a continuously variable transmission for turning, but the control valve is a double-action type controlled object, For example, as long as the fluid pressure cylinder or the like is switched and controlled, the present invention can be applied to any device without being limited to the speed change operation device.

(6) In the above embodiment, the pair of left and right straight clutches are illustrated as a pair of left and right meshing clutches. Instead, the right pair of straight clutches is configured as a multi-plate friction clutch. May be.

(7) In the above-described embodiment, the combine is exemplified as the vehicle provided with the speed change operation device. However, the combine is not limited to the combine, and a tractor or other agricultural machine may be used, or a construction work vehicle or the like may be used.

Overall side view of the combine in the first embodiment Schematic configuration diagram showing the transmission structure in the first embodiment Control block diagram in the first embodiment The figure which shows the structure of the hydraulic control unit in 1st Embodiment. The figure which shows the relationship between the transmission position and transmission output in 1st Embodiment. Flowchart of control operation in the first embodiment The figure which shows the relationship between the operation position of the turning lever in 1st Embodiment, and a speed ratio. Control block diagram in the second embodiment The figure which shows the relationship between the shift position and shift output in 2nd Embodiment. The figure which shows the relationship between the shift position and shift output in 2nd Embodiment. The figure which shows the relationship between the shift position and shift output in 2nd Embodiment. Control block diagram in the third embodiment The figure which shows the relationship between the speed change position and speed change output in 3rd Embodiment. The figure which shows the relationship between the speed change position and speed change output in 3rd Embodiment. The figure which shows the relationship between the speed change position and speed change output in 3rd Embodiment. Control block diagram in the fourth embodiment The figure which shows the relationship between the transmission position and transmission output in 4th Embodiment. Control block diagram in the fifth embodiment The figure which shows the speed change position and speed change output in 5th Embodiment. The figure which shows the relationship between the target rotational speed and target shift position in 5th Embodiment. Flowchart of control operation in the fifth embodiment Flowchart of control operation in the fifth embodiment Flowchart of control operation in the fifth embodiment

Explanation of symbols

1L Traveling device on the left side 1R Traveling device on the right side 7 Continuously variable transmission for straight travel 8 Continuously variable transmission for turning 14 Speed command means (transmission operation tool)
15 Object (swash plate for turning)
16, 80 Shift control means (turning operation mechanism)
27 Transmission state switching means 56 Turning command means (turning lever)
58, 59 Speed detection means (rotation sensor)
60 Shift position detection means (transverse shift position sensor)
61 Shift position detecting means (shift position sensor for turning)
72 Turning operation mode change setting means (turning state setting device)
74 Turning force setting means H Speed control means, traveling state switching control means MO target rotational speed command means SV servo means (hydraulic servo mechanism)

Claims (8)

A straight transmission state in which the output of the continuously variable continuously variable transmission is transmitted to each of the left and right traveling devices, and the output of the continuously variable continuously variable transmission is transmitted to the right traveling device and the continuously variable transmission for turning. To the left traveling device, and the output of the continuously variable continuously variable transmission is transmitted to the left traveling device and the output of the continuously variable transmission for the right is transmitted to the right traveling device. Transmission state switching means switchable to the transmission state for right turn transmitted to the traveling device;
Turn command means for commanding straight, left turn and right turn;
Speed command means for commanding the running speed;
Speed control means for shifting the straight-line continuously variable transmission and the turning continuously variable transmission; and
A traveling state switching control means for switching the transmission state switching means so as to be in the traveling state commanded by the turning command means;
The speed control means is
When the straight command is commanded by the turning command means, one of the continuously variable continuously variable transmission and the continuously variable transmission for turning is commanded by the speed command means. A straight-ahead control in which a speed change operation is performed so that the traveling speed is reached, and the other continuously variable transmission is operated to have the same speed as the speed detected by the speed detecting means for detecting the speed of the one continuously variable transmission. Execute the process, and
When left turn and right turn are commanded by the turn command means, the continuously variable transmission for straight travel is operated to change to a traveling speed commanded by the speed command means, and A turning control device for a work vehicle configured to execute a turning control process for changing a speed of a continuously variable transmission for turning to a target speed for turning,
The speed control means is
In the straight-ahead control process, the speed change operation speed for shifting the continuously variable transmission device so as to be the same speed as the speed detected by the speed detecting means is continuously set to the traveling speed commanded by the speed command means. A work vehicle turning control device configured to perform a speed change operation on the continuously variable continuously variable transmission and the continuously variable transmission for turning in a state in which the speed is set to be greater than a speed change operation speed at which the speed change operation is performed. The speed control means comprises mechanical servo means and speed change control means for operating the speed change actuator to change speed,
The mechanical servo means shifts the linearly variable continuously variable transmission so as to have a traveling speed commanded as a change in operating position by a position change operation-type shift operating tool as the speed command means. Configured to
2. The operation according to claim 1, wherein the shift control means is configured to shift the continuously variable transmission for turning with the shift actuator so that the speed is the same as the speed detected by the speed detecting means. Car turning control device. The turn command means is a straight drive command position for commanding the straight travel, a left turn command range for commanding the left turn adjacent to the command command position for straight travel, and a position adjacent to the command command position for straight travel It is configured to be freely movable over a right turn command range that commands a right turn,
An operation position detecting means for detecting an operation position of the turning command means is provided,
A first turning state in which the continuously variable continuously variable transmission and the continuously variable transmission for turning decelerate the traveling speed of the traveling device on the turning side from the traveling speed of the traveling device on the straight traveling side; And a third turning state in which the traveling direction of the traveling device on the turning side is made to travel in the direction opposite to the traveling direction of the traveling device on the straight traveling side. ,
In each of the left turn command range and the right turn command range, as the turn command means is operated to the side away from the straight advance command position, the first turn state, the second turn state, and A turning operation mode change setting means for artificially changing and setting a relationship between an operation position in the turning command range of the turning command means and a target turning state on condition that the third turning state is sequentially commanded. Provided,
The speed control means is
Based on the detection information of the operation position detection means and the setting information of the turning operation mode change setting means, the stepless speed change for straight travel so that a turning state is obtained corresponding to the operation position of the turning command means. The turning control device for a work vehicle according to claim 1, wherein the device and the continuously variable transmission for turning are operated to change speed. In the first turning state, the turning operation mode change setting means sets the traveling speed of the turning-side traveling device so that the turning command means is moved to the side away from the straight-ahead command position. Set a mode to increase the amount of deceleration when decelerating from the traveling speed of
In the third turning state, the traveling direction of the traveling device on the turning side travels in a direction opposite to the traveling direction of the traveling device on the straight traveling side as the turning command means is operated to the side farther from the rectilinear command position. The turning control device for a work vehicle according to claim 3, wherein the turning control device is configured to set a form for increasing a traveling speed when the operation is performed. The turn command means is a straight drive command position for commanding the straight travel, a left turn command range for commanding the left turn adjacent to the command command position for straight travel, and a position adjacent to the command command position for straight travel It is configured to be freely movable over a right turn command range that commands a right turn, and moves in a direction away from the straight advance command position in each of the left turn command range and the right turn command range. It is configured to command a larger turning state as the amount is larger,
The speed control means is
In each of the left turn command range and the right turn command range, an operation of the turn command means is performed in a small operation range in which the amount of movement of the turn command means in a direction away from the straight command position is small. The amount of change in the turning force with respect to the change per unit of position becomes insensitive turning state,
Further, as the amount of movement in the direction away from the straight command position is operated to the large operation range, the amount of change in the turning force with respect to the change per unit of the operation position of the turn command means is In a form that becomes a sensitive turning state larger than the amount of change of the turning force in the small operation range, the target turning force is obtained,
Based on the command information of the turning command means, the linearly variable continuously variable transmission and the continuously variable transmission for turning are operated so as to achieve the target turning force. Item 3. A work vehicle turning control device according to item 1 or 2. The correlation between the operation position of the turning command means and the target turning force is set in such a form that the insensitive operation state is set in the small operation range and the sensitive operation state is set in the large operation range. In addition, there is provided a turning force setting means that can freely change the correlation based on an artificial operation command,
Based on the command information of the turning command means and the setting information of the turning force setting means, the speed control means makes the straight-line continuously variable transmission and the turning The turning control device for a work vehicle according to claim 5, wherein the continuously variable transmission device is configured to perform a speed change operation. The turn command means is a straight drive command position for commanding the straight travel, a left turn command range for commanding the left turn adjacent to the command command position for straight travel, and a position adjacent to the command command position for straight travel It is configured to be freely movable over a right turn command range for commanding a right turn, and in each of the left turn command range and the right turn command range in a direction away from the straight advance command position. It is configured to command a larger turning state as the amount of movement increases,
In each of the left turn command range and the right turn command range, the turning force when the turn command means is operated to the maximum operation position in which the movement amount in the direction away from the straight drive command position is the maximum is increased or decreased. An artificially operated turning force change setting means capable of setting and changing the correlation between the operation position in the turning operation range of the turning command means and the target turning force in a state of changing, is provided.
The speed control means is
Based on the command information of the turning command means and the setting information of the turning force change setting means, it is obtained by the correlation set in the turning command range of the turning command means and the turning force change setting means. The work vehicle according to claim 1 or 2, wherein the straight-running continuously variable transmission and the turning continuously variable transmission are operated so as to achieve the target turning force. Swivel control device. A pair of shift position detecting means for detecting a shift position of the geared operating body in each of the linearly variable continuously variable transmission and the turning continuously variable transmission; and
A pair of shift output detecting means for detecting an output rotation speed in each of the continuously variable continuously variable transmission and the continuously variable continuously variable transmission;
A target rotational speed command means for commanding a target rotational speed of each of the continuously variable continuously variable transmission and the continuously variable continuously variable transmission;
The shift control means is
In each of the straight traveling control process and the turning control process,
Based on reference information set for obtaining a target shift position of the gear to be operated corresponding to the rotational speed to be output for each of the linearly variable continuously variable transmission and the continuously variable continuously variable transmission. Then, the target shift position of the shift target object corresponding to the rotational speed to be output is obtained, and the detected value of each of the pair of shift position detecting means becomes the target shift position of the shift target object. And configured to shift the operated body for shifting, and
It is configured to be switchable between a travel control mode for executing travel control and a calibration processing mode for executing calibration processing for detection values of the pair of shift position detecting means,
As the calibration process in the calibration process mode, the straight-line continuously variable transmission for each of the straight-line continuously variable transmission and the turning continuously variable transmission based on the detection value of the shift output detection means. And the shift position detection corresponding to each of the continuously variable transmissions in the reference rotation state by shifting the operation target for shifting so that each of the continuously variable transmissions for turning is in the reference rotation state. The work vehicle turning control device according to any one of claims 1 to 7, wherein the reference information about the shift position detecting means is calibrated based on a detected value of the means.

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