JP5222084B2 - Work vehicle turning control device - Google Patents

Description

  In the present invention, the drive state of the pair of left and right traveling devices is a straight drive state, the brake turning state in which the traveling device inside the turn stops or substantially stops, and the traveling device inside the turn is driven so as to travel in the direction opposite to the aircraft traveling direction. A travel drive means switchable to a reverse turning state, a travel drive state selection means for selecting and commanding any one of the straight drive state, the brake turn state, and the reverse turn state, and the travel drive state selection means. The present invention relates to a turning control device for a work vehicle provided with control means for controlling the travel drive means so as to be in a selected drive state based on a command.

  The above-mentioned turning control device for a work vehicle selects a driving state by the traveling driving state selection means, so that the driving state of the pair of left and right traveling devices is a straight driving state, and the braking device that stops or substantially stops the traveling device inside the turning. As a configuration capable of switching to a reverse turning state in which the traveling device and the traveling device inside the turning are driven so as to travel in the direction opposite to the airframe traveling direction, a desired turning state suitable for the work situation can be revealed. However, this type of work vehicle turning control device has conventionally been configured as follows as applied to a combine as an example of a work vehicle.

That is, as the traveling drive means, a friction-type hydraulic clutch exclusively for reverse rotation for revealing a reverse rotation state for driving the traveling device inside the turn so as to travel in the direction opposite to the aircraft traveling direction, and the traveling inside the turn Each of the frictional hydraulic clutches for exclusive use of the brake turning to bring out a brake turning state in which the rotation of the device stops or substantially stops is provided separately, and one of the frictional hydraulic clutches is selectively turned on. In some cases, the pressure oil supply path is switched as much as possible, and the operation pressure of the frictional hydraulic clutch is adjusted so that the operation pressure corresponds to the turning state selected by the travel drive state selection means. (For example, refer to Patent Document 1).
In addition, in the thing shown in patent document 1, apart from the friction-type hydraulic clutch exclusively for reverse rotation and the friction-type hydraulic clutch exclusively for brake turning, the traveling device inside the turning is slower than the traveling device outside the turning in the aircraft traveling direction. A friction-type hydraulic clutch dedicated to slow turning is also provided for revealing a slowly turning state that rotates at a low speed.

JP 2000-264243 A

  In the above-described conventional configuration, the frictional hydraulic clutch dedicated to reverse rotation for revealing the reverse rotation state that drives the traveling device inside the turn so as to travel in the direction opposite to the aircraft traveling direction, and the traveling device inside the turn The friction type hydraulic clutch dedicated to the brake turning is provided separately to reveal the brake turning state in which the rotation stops or substantially stops. The structure of the means is complicated, and there is a disadvantage incurring high costs.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a turning control device for a work vehicle that simplifies the configuration of the traveling drive means by also using a friction type hydraulic clutch, and that can appropriately bring out a brake turning state. The point is to provide.

The turning control device for a work vehicle according to the present invention is configured such that the driving state of the pair of left and right traveling devices is a straight drive state, the braking turning state in which the traveling device on the inside of the turn is stopped or substantially stopped, and the traveling device on the inside of the turning is the body traveling direction. Traveling drive means switchable to a reverse turning state for driving in the reverse direction;
Traveling drive state selection means for selecting and commanding any one of the straight drive state, the brake turning state, and the reverse turning state;
A work vehicle turning control device provided with control means for controlling the travel drive means so as to be in a selected drive state based on a command of the travel drive state selection means,
By changing the operating pressure of the friction-type hydraulic clutch that transmits the propulsive force that travels in the direction opposite to the aircraft traveling direction to the traveling device inside the turning of the pair of left and right traveling devices, the traveling drive means, It is configured to be switchable between the brake turning state and the reverse turning state,
An operating pressure adjusting means that adjusts an operating pressure of the friction type hydraulic clutch by changing and adjusting a supply pressure of pressure oil supplied from a hydraulic pressure source, and a pair of rotational speeds of the pair of left and right traveling devices that are detected separately. Traveling speed detection means,
The control means is
When the reverse rotation state is instructed by the travel drive state selection means, reverse rotation processing is performed for adjusting the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the reverse rotation operation pressure. And, when the brake turning state is commanded by the travel drive state selection means, the brake turning processing for adjusting the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the brake turning operation pressure. And is configured to perform
As the brake turning process, a target operation pressure setting process for setting a target operation pressure as the brake turning operation pressure, and the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the target operation pressure. An operation pressure adjustment process to be controlled and a brake turning state determination process for determining whether or not the traveling drive means is in the brake turning state based on detection information of the pair of traveling speed detection means are executed. And
As the target operation pressure setting process,
Immediately after the travel drive state selection means is switched from the straight drive state or the reverse turning state command to the brake turning state command, a preset initial operation pressure is set as the target operation pressure, and then Is configured to execute a process of setting a corrected operation pressure obtained by changing the pressure from the initial operation pressure as the target operation pressure until it is determined in the brake rotation state determination process that the vehicle is in the brake rotation state. ,
The control means, as the brake turning state determination processing,
Based on the detection information of the pair of traveling speed detecting means, when the rotational speed of the traveling device outside the turn is equal to or higher than the setting speed for determining condition switching, the rotational speed of the traveling device inside the turn is less than the brake determining speed. If there is, the brake turning state is determined, and if the rotational speed of the traveling device outside the turn is less than the determination condition switching set speed, the inside of the turning with respect to the rotational speed of the traveling device outside the turning is determined. If the speed ratio of the rotational speed of the traveling device is less than the set ratio, a process for determining that the vehicle is in the brake turning state is executed .

  That is, the travel drive means changes the operating pressure of the frictional hydraulic clutch that transmits a propulsive force that travels in a direction opposite to the advancing direction to the traveling device inside the turning of the pair of left and right traveling devices. The control means is configured to be switchable between the brake turning state and the reverse turning state, and when the reverse driving state is instructed by the traveling drive state selecting means, the control means is configured to operate an operating pressure of the friction hydraulic clutch. When the reverse rotation turning process for adjusting the operation pressure adjusting means to execute the reverse rotation turning operation pressure is executed, and the brake turning state is commanded by the traveling drive state selection means, the friction hydraulic clutch The brake turning process for adjusting the operation pressure adjusting means is executed so that the operation pressure becomes the brake turning operation pressure.

  When the explanation is added, the operating force of the friction type hydraulic clutch that transmits the propulsive force traveling in the direction opposite to the aircraft traveling direction is transmitted to the traveling device outside the turning while transmitting the propulsive force traveling in the aircraft traveling direction. When a large operating force close to the maximum value is set, the traveling device on the inner side of the turn is driven with a large propulsive force in the direction opposite to the direction of travel of the aircraft, so that the reverse turning state occurs. If the operating force is too small, the pressure contact force of the hydraulic clutch becomes weak, and the propulsive force in the direction opposite to the traveling direction of the aircraft becomes a semi-transmission state smaller than that in the reverse turning state, and is driven in the semi-transmission state. The propulsive force in the direction opposite to the aircraft traveling direction transmitted to the traveling device inside the turning and the propulsive force in the aircraft traveling direction given to the traveling device inside the turning by the driving force of the traveling device outside the turning balances and turns. By the rotation of the inner driving apparatus for revealing the pseudo brake state to be a state of stopping or substantially stopping is to obtain the brake turning state.

  As a result, the traveling drive means switches between the state of turning in the reverse turning state and the state of turning in the brake turning state by changing and adjusting the operating pressure of one friction type hydraulic clutch. Thus, it is possible to perform turning in each turning state. In other words, the selected turning state can be obtained by adjusting the operating pressure of one frictional hydraulic clutch, regardless of whether the reverse turning state or the brake turning state is selected. It is not necessary to provide a dedicated friction hydraulic clutch for displaying only the turning state and a dedicated friction hydraulic clutch for displaying only the brake turning state, and the number of parts is reduced accordingly. Can be simplified.

  Then, the control means adjusts the operation pressure so that the operation pressure of the friction hydraulic clutch becomes the target operation pressure, as the brake rotation processing, the target operation pressure setting processing for setting the target operation pressure as the brake rotation operation pressure. An operation pressure adjusting process for controlling the means, and a brake turning state determining process for determining whether or not the traveling drive means is in a brake turning state based on the detection information of the pair of traveling speed detecting means, As the operation pressure setting process, immediately after switching to the command of the brake turning state, a preset initial operation pressure is set as the target operation pressure, and thereafter, the brake turning state is determined by the brake turning state determination process. Until it is determined, the process of setting the corrected operation pressure obtained by changing the pressure from the initial operation pressure as the target operation pressure is executed.

  In other words, immediately after switching to the command of the brake turning state, the preset initial operating pressure is set as the target operating pressure to adjust the operating pressure of the friction hydraulic clutch, so that it can be quickly performed with little time delay. The target operation is corrected by changing the pressure from the initial operation pressure until it is determined that the brake is turning based on the detection information of the pair of travel speed detecting means. Since the pressure is set, even if the amount of friction braking applied to the traveling device by the ground fluctuates due to the hardness or the like of the ground, it is possible to appropriately set the brake turning state.

  Therefore, according to the first characteristic configuration, the turning control of the work vehicle that enables simplification of the configuration of the traveling drive means by using the friction type hydraulic clutch together, and also enables the brake turning state to be appropriately set. We have been able to provide equipment.

Further, according to the first characteristic configuration, when the rotational speed of the traveling device on the outside of the turn is traveling at a high speed that is equal to or higher than the set speed for switching the determination condition, the control means When the speed is less than the preset brake judgment speed, it is clear that the speed difference between the left and right traveling devices is sufficiently large and the work vehicle is turning with a smaller turning radius. It is determined that it is.

  By the way, if the work vehicle is traveling on a farm field, the brake determination speed is set to a very small value close to zero speed. Even in the turning state corresponding to the turning state, the friction braking force due to the friction with the ground is weak because the rotational speed of the traveling device inside the turning is not less than the brake determination speed and cannot be distinguished from the brake turning state. For this reason, the brake determination speed is set to a value larger than the zero speed by a set amount.

  When the rotational speed of the traveling device outside the turn is traveling at a low speed lower than the setting speed for switching the determination condition, the speed ratio of the rotational speed of the traveling device inside the turn to the rotational speed of the traveling device outside the turn is If it is less than the set ratio, it is determined that the brake is turning. That is, when the traveling device on the outside of the turn is traveling at a low speed, if the traveling device on the inside of the turn is less than the brake determination speed, the speed difference between the left and right traveling devices is reduced, so that the brake turning Although it may not be possible to accurately determine whether or not the vehicle is in a state, it is determined whether or not the speed ratio of the rotational speed of the traveling device inside the turn to the rotational speed of the traveling device outside the turn is less than the set ratio. Thus, even if the traveling device on the outer side of the turn is traveling at a low speed lower than the set speed for switching the discrimination condition, whether or not the speed difference between the left and right traveling devices is a speed difference for turning according to the speed at that time. In other words, it is possible to appropriately determine whether or not the brake is turning.

Therefore, according to the first characteristic configuration, it is possible to appropriately determine whether or not the braking device is in the brake turning state regardless of the speed of the traveling device outside the turning.

The second characteristic configuration of the present invention, in addition to the first feature configuration range, said control means, said target operating pressure setting process, as the initial operating pressure, the variation of the brake rotation operation pressure is predicted The operation pressure that is the lowest or the operation pressure close thereto is set, and the correction operation pressure is set to the operation pressure that is gradually increased from the initial operation pressure. is there.

  That is, when adjusting the operating pressure adjusting means so that the operating pressure of the friction type hydraulic clutch becomes the operating pressure for turning the brake, when a pseudo brake state appears, the difference in the road surface condition and traveling speed of the field It is predicted that the brake turning operation pressure required to make the brake turning state will fluctuate due to the above, but the control means sets the target operation pressure when operating the friction hydraulic clutch. In the target operation pressure setting process, the minimum operation pressure in the range in which the fluctuation of the brake turning operation pressure is predicted or an operation pressure close thereto is set as the initial operation pressure. The operation pressure is set by gradually increasing the pressure from the initial operation pressure.

  By setting the target operation pressure in this manner, the friction hydraulic clutch immediately after the brake turning state is commanded by the traveling drive state selection means regardless of the state of the road surface of the field and the traveling speed. It is possible to avoid switching to the reverse rotation state accidentally because the operation pressure becomes too strong, and the operation pressure obtained by gradually increasing the pressure from the initial operation pressure is set as the correction operation pressure. Even if the operation pressure is insufficient immediately after the state is commanded, the operation pressure gradually increases and can be accurately switched to the brake turning state. In addition, by gradually increasing the operation pressure in this way, it is possible to perform a smooth turning operation with less shock due to a sudden increase in the operation pressure.

Therefore, according to the second characteristic configuration, it is possible to perform a smooth turning operation while avoiding the accidental switching to the reverse turning state and the occurrence of a shock due to a sudden increase in operating pressure.

According to a third characteristic configuration of the present invention, in addition to the second characteristic configuration, after the control means determines that the brake turning state is in the brake turning state determination process in the target operation pressure setting process. When it is detected that the rotational speed of the traveling device inside the turn is equal to or higher than the determination threshold value, an operation pressure reduction process for setting a value obtained by reducing a set amount from the correction operation pressure at that time as the target operation pressure. In that it is configured to run.

  That is, in the target operation pressure setting process, the corrected operation pressure obtained by gradually increasing the pressure from the initial operation pressure is set as the target operation pressure until it is determined that the brake turning state is determined in the brake turning state determination process. As a result of gradually increasing the correction operating pressure without properly determining whether or not the brake is in the turning state, the operating pressure of the friction hydraulic clutch may become too strong and switch to the reverse turning state. There is. Then, when switching to the reverse rotation state as described above, the friction hydraulic clutch is in a transmission state by a strong pressure contact force, and the traveling device inside the rotation is reversely driven at a relatively high speed.

  Therefore, if it is determined in the brake turning state determination process that the brake turning state is in effect, and if it is detected that the rotational speed of the traveling device inside the turn is equal to or higher than the determination threshold value, the reverse rotation is performed. Since there is a possibility of switching to the turning state, in such a case, a value obtained by reducing a set amount from the corrected operation pressure is set as the target operation pressure. As a result, it is possible to avoid the traveling device on the inner side of the turn from being driven in reverse.

Therefore, according to the third characteristic configuration, it is possible to avoid the correction operation pressure from becoming too strong and erroneously switching to the reverse rotation state.

According to a fourth feature configuration of the present invention, in addition to the third feature configuration, the control unit is configured to perform the target driving pressure setting process in which the travel drive state selection unit is configured to perform the straight drive state or the reverse rotation state command based on the command. If the rotational speed of the traveling device outside the turn is less than the low speed state determination speed set lower than the determination condition switching set speed when the brake turning state command is switched, the operation pressure The lowering process is configured not to be executed.

  That is, if the rotational speed of the traveling device outside the turn is less than the low-speed state determination speed when the command is switched to the brake turning state command, depending on the road surface condition at that time, the brake turning When executing the process of setting the corrected operation pressure obtained by gradually increasing the pressure from the initial operation pressure as the target operation pressure until it is determined in the state determination process that the vehicle is in the brake turning state, the brake turning state; A slow turning state in which the traveling device inside the turn rotates in the same rotational direction as the traveling device outside the turn and is driven at a lower speed than the rotational speed of the traveling device outside the turn may repeatedly appear.

  When the slow turning state appears, the rotational speed of the traveling device inside the turn becomes higher than the rotational speed to be determined as the brake turning state, and at that time, the traveling device inside the turn May be mistakenly determined that the rotational speed of the motor has become equal to or higher than the threshold for determination. As a result, when the operation pressure lowering process is performed in which the target operation pressure is set to a value obtained by reducing the set amount from the corrected operation pressure in spite of the gentle turning state, the operation pressure of the friction hydraulic clutch becomes insufficient. Thus, there is a possibility that the slow turning state may continue without entering the brake turning state.

  Accordingly, when the rotational speed of the traveling device outside the turn is less than the low speed state determination speed when the command is switched to the brake turning state command, the operation pressure reduction process is not executed. It is possible to avoid the disadvantage that the slow turning state continues.

According to a fifth feature configuration of the present invention, in addition to any one of the second feature configuration to the fourth feature configuration, in the target operating pressure setting process, the control drive unit selects the travel drive state selection unit in the straight drive state or When switching from the reverse turning state command to the brake turning state command, the rotational speed of the traveling device outside the turning is set to a lower speed than the determination condition switching setting speed. If the speed is less than the speed, the initial operating pressure is set as the target operating pressure immediately after the travel drive state selection means is switched to the brake turning state command, and thereafter the pressure is changed from the initial operating pressure. The correction operation pressure is set so as not to execute the process of setting the corrected operation pressure as the target operation pressure.

According to the fifth characteristic configuration, if the rotation speed of the traveling device outside the turn is less than the extremely low speed determination speed when the command is switched to the brake turning state command, the turn Even if the operating pressure of the frictional hydraulic clutch is adjusted so that the inner traveling device is stopped, it is likely to be dragged by the propulsive force of the traveling device on the outer side of the turn, so that If a follow-up state occurs, if the process of setting the corrected operation pressure, which is changed from the initial operation pressure as described above, as the target operation pressure is executed, the operation pressure becomes too strong and reverses. There is a high possibility that the vehicle body turns and the vehicle body turns suddenly.

  Therefore, if the rotational speed of the traveling device outside the turn is less than the extremely low speed determination speed when switched to the brake turning state command, the pressure from the initial operation pressure is increased. By avoiding the process of setting the changed corrected operation pressure as the target operation pressure, it is possible to avoid the reverse rotation state and perform an appropriate brake turning state.

According to a sixth feature configuration of the present invention, in addition to any one of the second feature configuration to the fifth feature configuration, the travel drive state selection means includes a straight command state in which straight travel is commanded and a turn command state in which swivel is commanded The turning radius command means for commanding a turning radius index indicating the magnitude of the turning radius in the turning command state, and a turning mode command means for selecting and commanding the brake turning mode and the reverse turning mode are provided. ,
The control means is
When the turning mode command means instructs the brake turning mode, and the turning radius command means instructs the turning radius index to command the minimum turning radius, the brake turning state is instructed. And the processing for brake turning is executed, the reverse turning mode is instructed by the turning mode command means, and the turning radius index for instructing the minimum turning radius is instructed by the turning radius command means The reverse rotation mode is determined to be commanded, and the reverse rotation processing is executed, and
When the turning mode command means instructs the brake turning mode, and the turning radius command means instructs the turning radius index to command a turning radius larger than the minimum turning radius, the friction-type hydraulic pressure As an operation pressure of the clutch, an operation pressure that is smaller than the initial operation pressure and becomes smaller as a larger turning radius is commanded by the turning radius index is set, and the operation pressure adjusting means is set so as to obtain the operation pressure. The low-speed turning process for the brake turning mode to be controlled is executed, the reverse turning mode is commanded by the turning mode command means, and a turning radius larger than the minimum turning radius is commanded by the turning radius command means When a turning radius index is commanded, the operating pressure of the frictional hydraulic clutch is smaller than the operating pressure for reverse rotation and the turning radius index The operation pressure is set to be smaller as a larger turning radius is commanded, and the low-speed turning process for the reverse turning mode for controlling the operation pressure adjusting means so as to obtain the operation pressure is executed. It is in.

According to the sixth characteristic configuration, the turning radius index for commanding a turning radius larger than the minimum turning radius by the turning radius command means in a state where the brake turning mode is commanded by the turning mode command means. Is executed, the low-speed turning process for the brake turning mode is executed, and when the turning radius indicator for instructing the minimum turning radius is instructed by the turning radius instruction means, the brake turning state is instructed. The brake turning process is executed by discriminating that it is a thing.

    On the other hand, when the turning mode command means commands the reverse turning mode, the turning radius command means instructs the turning radius index to command a turning radius larger than the minimum turning radius. When the low-speed turning process for the reverse turning mode is executed and the turning radius index commanding the minimum turning radius is commanded by the turning radius command means, it is determined that the reverse turning state is commanded. The reverse turning process is executed.

  In the low-speed turning process for the brake turning mode and the low-speed turning process for the reverse turning mode, an operation pressure that decreases as a large turning radius is commanded by the turning radius index is set as the operation pressure of the friction hydraulic clutch. Thus, the operating pressure adjusting means is controlled so as to obtain the operating pressure, so that it is possible to command turning states with different turning radii.

  Accordingly, the desired turning mode can be instructed by the turning mode command means, and the desired turning radius can be instructed by the turning radius instruction means. A state can be commanded.

  Hereinafter, the case where the embodiment of the turning control device for a work vehicle according to the present invention is applied to a combine as an example of the work vehicle will be described with reference to the drawings.

  As shown in FIG. 1, a cutting unit 4 is supported at a front portion of a vehicle body supported by right and left crawler travel devices 1 and 1 by a lifting cylinder 3 so as to be driven up and down around a horizontal axis P1. A driving unit 5 is provided on the right side of the front part of the vehicle, an engine 7 is provided on the lower side of the driving seat 6 of the driving unit 5, a threshing device 8 is provided on the left side of the rear part of the vehicle body, and a glen on the right side of the rear part of the vehicle body. A tank 9 is provided to constitute a self-removing combine that is an example of a work vehicle.

  As shown in FIG. 2, the power of the engine 7 is transmitted to the input shaft of the hydrostatic continuously variable transmission 11 for traveling speed change via the transmission belt 19, the input pulley 17, and the input shaft 16. Is transmitted to the cutting unit 4 via the transmission belt 20 and the hydrostatic continuously variable transmission 21 for cutting and shifting.

Next, the transmission mechanism inside the mission case will be described with reference to FIG.
An input shaft 22 is supported on the upper part of the transmission case 10, and transmission gears 23 and 24 are fixed to the input shaft 22 by a spline structure. An output shaft 11c of the hydrostatic continuously variable transmission 11 is inserted into the transmission case 10 and connected to the transmission gear 24 (input shaft 22) by a spline structure. Further, a high-speed gear 25 and a low-speed gear 26 are externally fitted to the sub-transmission transmission shaft 27 supported on the upper portion of the transmission case 10 so as to be relatively rotatable, and the transmission gear 23 and the high-speed gear 25, the transmission gear 24 and the low-speed gear 26 are fitted. The shift member 28 is externally fitted to the sub-transmission transmission shaft 27 so as to be integrally rotatable and slidable by a spline structure. The transmission gear 23 and the high-speed gear 25, the transmission gear 24 and the low-speed gear 26, and the shift member 28 constitute an auxiliary transmission, and the input shaft 22 is engaged by engaging the shift member 28 with the high-speed and low-speed gears 25 and 26. Is transmitted to the sub-transmission transmission shaft 27 after being shifted to high and low two stages (low speed and high speed).
The auxiliary transmission is normally slid to a position where the shift member 28 meshes with the high speed gear 25 to set the high speed position.

  A linear transmission shaft 29 is supported at the lower part of the transmission case 10, and a transmission gear 31 is fixed to the linear transmission shaft 29. The transmission gear 31 is engaged with a transmission gear 30 fixed to the auxiliary transmission transmission shaft 27. Yes. Further, a pair of left and right output gears 32R and 32L are externally fitted to the linear transmission shaft 29 so as to be relatively rotatable, and a pair of left and right occlusion portions 33R and 33L are integrally rotated with the linear transmission shaft 29 by a spline structure. It is slidably fitted outside. And the right side clutch 34 is comprised between the right output gear 32R and the right occlusion part 33R, and the left side clutch 34 is comprised between the left output gear 32L and the left occlusion part 33L.

Next, the right and left side clutches 34 will be described.
Spline portions are formed on the outer surfaces of the right and left side portions of the straight transmission shaft 29, and the right occlusion portion 33R and the left occlusion portion 33L are externally fitted to the spline portion of the straight movement transmission shaft 29 so as to be integrally rotatable and slidable. The receiving member 40 is externally fitted to the spline portion of the linear transmission shaft 29 so as to be integrally rotatable. The right and left occlusal portions 33R and 33L are urged by the receiving member 40 and the spring 41 to the occlusal side of the right and left output gears 32R and 32L. The right and left occlusal portions 33R and 33L are engaged with the right and left output gears 32R and 32L, so that the right and left side clutches 34 are in a transmission state. And transmitted to the right and left crawler travel devices 1 via the left side clutch 34.
Further, by supplying hydraulic oil into the oil chambers formed between the right and left output gears 32R and 32L and the right and left occlusion portions 33R and 33L, the right and left occlusion portions 33R and 33L The right and left occlusal portions 33R and 33L are slid to the side where they are separated against the biasing force of the spring 41, and the right and left side clutches 34 are in a clutch disengaged state (disengaged state). When the hydraulic oil is discharged, the right and left side clutches 34 are engaged (transmission state) by the biasing force of the spring 41.

  The left and right transmission shafts 35 are supported on the same axis so as to be arranged side by side on the same axis, and the left and right transmission gears 36 fixed to the left and right transmission shafts 35 are connected to the right output gear 32R and the left. The left and right transmission gears 37 fixed to the left and right transmission shafts 35 are engaged with the transmission gears 39 fixed to the right and left axles 38, respectively. The right and left axles 38 are connected to the right and left crawler travel device 1 sprockets.

  If both the left and right side clutches 34 are engaged, the power of the input shaft 22 is transmitted to the sub-transmission transmission shaft 27, the transmission gears 30 and 31, the straight transmission shaft 29, the right and left side clutches 34, When the right and left output gears 32R and 32L, the transmission gear 36, the transmission shaft 35, the transmission gears 37 and 39, and the right and left axles 38 are transmitted to the right and left crawler travel devices 1, the aircraft goes straight. It becomes the transmission state which runs in the state.

Next, the structure of the turning transmission system for turning the vehicle body will be described.
A transmission shaft 44 is supported in the transmission case 10, and a transmission gear 45 fitted on the transmission shaft 44 so as to be relatively rotatable is engaged with a gear portion on the outer periphery of the right occlusion portion 33 </ b> R. A slow turning clutch 46 is provided between the gear 45. The slow swing clutch 46 is configured as a friction multi-plate type, and is operated to a transmission state (on state) when hydraulic oil is supplied, and is operated to a cut-off state (off state) when the hydraulic oil is discharged. .

  A revolving clutch case 47 is fitted on the linear transmission shaft 29 so as to be relatively rotatable, and a transmission gear 48 fixed to the transmission shaft 44 and a transmission gear 47 a on the outer periphery of the revolving clutch case 47 are engaged with each other. The turning clutch case 47 is configured to be bilaterally symmetrical, and a right and left turning clutch 49 is formed between the turning clutch case 47 and the right and left output gears 32R and 32L. The right and left turning clutch 49 is configured as a friction multi-plate type, and is operated in a transmission state by supplying hydraulic oil. The right and left turning clutches 49 are arranged so that the friction plates are dense with each other, and the right and left turning clutches 49 are in a semi-transmission state even when the hydraulic oil is discharged. .

  When the slow swing clutch 46 is operated in the transmission state, the power of the straight drive shaft 29 is used for the straight drive via the right occlusal portion 33R, the transmission gear 45, the slow swing clutch 46, the transmission shaft 44, and the transmission gear 48. Rotation in the same direction as the transmission shaft 29 is transmitted to the turning clutch case 47 as power lower than that of the linear transmission shaft 29. When one of the right and left side clutches 34 is operated in a disconnected state and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated in a transmission state, a transmission state is established. Through the turning clutch 49, the power in the same direction as that of the straight transmission shaft 29 is transmitted to one of the right and left output gears 32R and 32L by the rotation in the same direction as that of the straight transmission shaft 29. Low speed power is transmitted to the traveling device 1. At that time, the power of the straight drive shaft 29 is transmitted as it is to the other of the right or left output gears 32R, 32L.

  A transmission gear 52 is fitted on the transmission shaft 44 so as to be relatively rotatable. The transmission gear 52 is engaged with a transmission gear 51 provided on the auxiliary transmission transmission shaft 27 so as to be integrally rotatable. A reverse clutch 53 as a friction type hydraulic clutch is provided between the transmission shaft 44 and the transmission gear 52. The reverse clutch 53 is configured as a frictional multi-plate type, and is operated to a transmission state (ON state) when hydraulic oil is supplied, and is operated to a cutoff state (OFF state) when the hydraulic oil is discharged. The reverse clutch 53 can be operated in a braking state as will be described later by adjusting the supply pressure of the hydraulic oil.

  When the reverse clutch 53 is operated in the transmission state, the power of the sub-transmission transmission shaft 27 is reverse to the linear transmission shaft 29 via the transmission gears 51 and 52, the reverse clutch 53, the transmission shaft 44 and the transmission gear 48. It is transmitted to the turning clutch case 47 as directional rotation power. When one of the right and left side clutches 34 is operated in a disconnected state and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated in a transmission state, a transmission state is established. The rotational power in the direction opposite to that of the straight transmission shaft 29 is transmitted to one of the right or left output gears 32R and 32L via the turning clutch 49, and the reverse rotation is transmitted to the traveling device 1 on the corresponding side. Power is transmitted. At that time, the power of the straight drive shaft 29 is transmitted as it is to the other of the right or left output gears 32R, 32L.

  Further, by adjusting the supply pressure of the hydraulic oil to the reverse clutch 53, the brake can be brought into a braking state by adjusting the operation pressure so as to prevent the transmission shaft 44 from rotating. In this braking state, the transmission shaft can be set. The turning clutch case 47 is brought into a braking state via 44 and the transmission gear 48. When one of the right and left side clutches 34 is operated to the disconnected state, and the one of the right or left turning clutch 49 on the side where the side clutch 34 is disconnected is operated to the transmission state, the right or left side clutch 34 is operated. Of the output gears 32R and 32L, the side where the side clutch 34 is not disengaged is in a braking state, and the power on the opposite side transmits the power of the straight transmission shaft 29 as it is.

  Therefore, the transmission as described above includes the slow turning clutch 46, the reverse clutch 53, and the left and right side clutches 34 for switching the driving state of the pair of left and right traveling devices 1 between the straight traveling state and the turning state. A transmission mechanism provided in the case 10 corresponds to the travel drive means 100.

Next, the operation of the hydrostatic continuously variable transmission 11 for traveling speed change will be described with reference to FIG.
The pump 11P of the hydrostatic continuously variable transmission 11 is configured to be continuously variable from the neutral position N and the neutral position N to the high speed side of the forward F and the high speed side of the reverse R. The hydrostatic continuously variable transmission Eleven motors 11M are configured to be variable in two levels. A hydraulic cylinder 59 for operating the swash plate of the pump 11P of the hydrostatic continuously variable transmission 11 and a control valve 60 for supplying / discharging hydraulic oil to / from the hydraulic cylinder 59 are provided, and a shift lever 61 provided in the operating unit 5 is provided. And the control valve 60 are mechanically linked. Thus, by operating the speed change lever 61, the control valve 60 is operated and the hydraulic cylinder 59 is operated, and the pump 11P of the hydrostatic continuously variable transmission 11 is tilted to a position corresponding to the operation position of the speed change lever 61. Operate the board.

  A hydraulic cylinder 62 that operates the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 and an electromagnetically operated control valve 63 that supplies and discharges hydraulic oil to and from the hydraulic cylinder 62 are provided. A shift switch 61a is provided in the unit, and an operation signal of the shift switch 61a of the shift lever 61 is input to a control device 64 including a microcomputer. Thus, by operating the speed change switch 61a of the speed change lever 61, the control valve 63 is operated by the control device 64, the hydraulic cylinder 62 is operated, and the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 is operated at high speed. And it is the structure operated to a low-speed position.

  An operation position sensor 65 for detecting the operation position of the shift lever 61 is provided, and left and right axle rotation sensors 66R and 66L as traveling speed detecting means for detecting the rotational speeds of the left and right axles for detecting the traveling speed of the airframe. , And the detection values of the operation position sensor 65 and the left and right axle rotation sensors 66R and 66L are input to the control device 64. Detection of whether the swash plate of the motor 11M of the hydrostatic continuously variable transmission 11 is at the high speed position or the low speed position is recognized by the control device 64 based on the operation signal of the speed change switch 61a of the speed change lever 61.

Next, the hydraulic unit 57 that supplies and discharges hydraulic oil to and from the right and left side clutches 34 (the right and left occlusion portions 33R and 33L), the right and left turning clutch 49, the slow turning clutch 46, and the reverse rotation clutch 53. explain.
As shown in FIG. 4, the hydraulic unit 57 includes a right turn control valve 67, a left turn control valve 68, a relief valve 69, an unload valve 70, a proportional control valve 71, a turn switching control valve 72, and a reverse turn turn valve. A pilot valve 74 is provided. The external pipe 58 from the hydraulic pump 56 driven by the output shaft 11 c of the hydrostatic continuously variable transmission 11 is connected to the hydraulic unit 57, and the right turning control valve 67 is the oil path 29 b of the straight transmission shaft 29. Are connected to the right side clutch 34 and the right turning clutch 49, and the left turning control valve 68 is connected to the left side clutch 34 and the left turning clutch 49 via the oil passage 29b of the straight transmission shaft 29. ing.

  The right turn control valve 67 and the left turn control valve 68 are configured by electromagnetic operation that can be switched to two positions of supply positions 67a and 68a and discharge positions 67b and 68b, respectively. The return is energized. The unload valve 70 is configured in an electromagnetic operation type that can be switched between two positions of a blocking position 70a and a discharging position 70b, and is urged to return to the blocking position 70a. A proportional control valve 71 and a turning switching control valve 72 are connected in series to an oil passage 75 branched from between the right and left turning control valves 67 and 68 and the oil passage 29b of the transmission shaft 29 for straight travel. A switching control valve 72 is connected to the slow swing clutch 46 and the reverse clutch 53 via an oil passage 44 a of the transmission shaft 44.

  The proportional control valve 71 is composed of an electromagnetic proportional pressure reducing valve, and as will be described later, the slow swing clutch 46 and the reverse clutch 53 on the lower side of the hydraulic fluid flow path are adjusted by changing and adjusting the control current supplied from the control device 64. The supply pressure can be changed and adjusted. Therefore, the proportional control valve 71 constitutes an operating pressure adjusting means for adjusting the operating pressure of the reverse clutch 53 by changing and adjusting the supply pressure of the pressure oil supplied from the hydraulic source.

  The turning switching control valve 72 is configured as a pilot operated type that can be operated to a slow turning position 72a and a reverse turning position 72c, and is urged to return to the slow turning position 72a. A reverse turning pilot valve 74 is configured so that the pilot hydraulic oil branched from the oil passage 75 is supplied to the turning switching control valve 72 and operated to the reverse turning position 72c. The reverse turning pilot valve 74 has a supply position for supplying pilot hydraulic oil to the turning switching control valve 72 and a stop position for stopping the supply of pilot hydraulic oil and returning the turning switching control valve 72 to the slow turning position 72a. It is configured as an electromagnetic operation type that can be switched to a position and is urged to return to a stop position.

  The right turning control valve 67, the left turning control valve 68, the unload valve 70, the proportional control valve 71, and the reverse turning pilot valve 74 are controlled by a control device 64 as described later.

  Then, as shown in FIG. 5, the return command is urged to return to the straight command position N, and the turn command operation region extends from the straight command position N to the maximum operation position Rm on the right side and the maximum operation position Lm on the left side. A swing lever 77 capable of swinging operation is provided in the operation unit 5, and a swing lever sensor 80 is provided as a turn command position detecting means for detecting an operation position of the swing lever 77. It is input to the control device 64.

  The swivel lever 77 can be freely moved over the straight command position N and the swivel command operation area connected thereto, and the swivel lever sensor 80 has a maximum operation position (Rm, Lm), the command information corresponding to a larger target turning force, in other words, a smaller turning radius is instructed to the control device 64. The turning lever 77 and the turning lever sensor 80 are used to turn the turning radius command means. 200 is configured. Therefore, the turning radius command means 200 is switchable between a straight running command state for commanding straight running and a turning command state for commanding turning, and commands a turning radius index indicating the magnitude of the turning radius in the turning command state. It is configured.

  Further, a turning mode switch 78 for instructing switching to a slow turning mode, a brake turning mode, and a reverse turning mode is provided in the operation unit 5, and the operation position of the turning mode switch 78 is input to the control device 64. The switch 78 is configured to be freely switchable between a slow turning position for instructing a slow turning mode, a brake turning position for instructing a brake turning mode, and a reverse turning position instructing a reverse turning mode. The driving state of the travel driving means 100 is switched so as to correspond to the operation position.

  When the turning lever 77 is operated to the rectilinear command position N, the right and left turning control valves 67 and 68 are operated to the discharge positions 67b and 68b, the unload valve 70 is operated to the discharge position 70b, and the right and left The hydraulic oil is discharged from the side clutch 34 and the right and left turning clutch 49, the right and left side clutch 34 are operated to the transmission state, and the right and left turning clutch 49 are operated to the half transmission state. Since the right and left turning control valves 67 and 68 are operated to the discharge positions 67b and 68b and the unload valve 70 is operated to the discharge position 70b, the hydraulic oil from the hydraulic pump 56 passes to the transmission case 10 through the unload valve 70. Returned.

  As a result, the power of the input shaft 22 is transmitted to the sub-transmission transmission shaft 27, the transmission gears 30, 31, the linear transmission transmission shaft 29, the right and left side clutches 34 (the right and left occlusion portions 33R, 33L), the right and The aircraft is transmitted straight to the right and left crawler travel devices 1 via the left output gears 32R and 32L, the transmission gear 36, the transmission shaft 35, the transmission gears 37 and 39, and the right and left axles 38.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the slow turning position will be described.
When the turning mode switch 78 is operated to the slow turning position and the turning lever 77 is operated to the right from the straight command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a to unload. The valve 70 is switched to the shut-off position 70a, hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is shut off. The hydraulic oil is supplied to the right turning clutch 49 and is operated to the transmission state.

In this case, since the left turning clutch 49 is in a semi-transmission state, the power of the left side clutch 34 is transmitted from the left output gear 32L and the left turning clutch 49 to the right output gear 32R via the right turning clutch 49. The power slightly lower than that of the linear transmission shaft 29 is transmitted to the right output gear 32R by rotation in the same direction as the linear transmission shaft 29. As a result, the aircraft gently turns to the right.
When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil begins to be supplied to the slow swing clutch 46 via the control valve 72, and as the swing lever 77 is moved to the right in a direction away from the straight advance command position after moving out of the dead zone, the proportional control valve 71 becomes slower. The operation pressure of the swing clutch 46 is increased.

  As the operation pressure of the slow swing clutch 46 is increased by the proportional control valve 71 based on the operation position of the swing lever 77, the power of the straight drive shaft 29 is changed to the right occlusal portion 33R, the transmission gear 45, Through the turning clutch 46, the transmission shaft 44, the transmission gear 48, the turning clutch case 47 and the right turning clutch 49, the motive power at a lower speed than the straight traveling transmission shaft 29 is rotated in the same direction as the straight traveling transmission shaft 29. It is transmitted to the output gear 32R.

  In this case, the power from the left side clutch 34 (the left occlusal portion 33L) and the power from the slow turning clutch 46 are transmitted to the right output gear 32R at the same time. In the range where the operation pressure is low, the power from the left side clutch 34 (the left occlusion portion 33L) overcomes the power from the slow swing clutch 46, and the power from the left side clutch 34 (the left occlusion portion 33L). As a result, the right output gear 32R is driven. As a result, when the operating pressure of the gentle turning clutch 46 is low, the aircraft gradually turns to the right.

  When the amount of movement of the turning lever 77 to the right increases and the operating pressure of the slow turning clutch 46 increases, the power from the slow turning clutch 46 overcomes the power from the left side clutch 34 (left occlusal portion 33L). Thus, the right output gear 32R is driven by the power from the slow turning clutch 46. In this state, the right output gear is driven by the power from the slow turning clutch 46 rather than the left output gear 32L driven by the power of the straight transmission shaft 29 via the left side clutch 34 (the left engagement portion 33L). 32R will be driven at low speed and the aircraft will turn to the right. The turning state at this time corresponds to a low-speed turning turning state in which the traveling device inside the turning rotates at a lower speed than the traveling device outside the turning in the airframe traveling direction.

  When the swivel lever 77 is operated to the left from the rectilinear command position N and moves out of the dead zone, the left swivel control valve 68 is operated to the supply position 68a, the unload valve 70 is held at the shut-off position 70a, and the left side The hydraulic oil is supplied to the clutch 34 (the left occlusion portion 33L) and the left turning clutch 49, the left side clutch 34 (the left occlusion portion 33L) is operated to be disconnected, and the left turning clutch 49 is operated with the hydraulic oil. Is operated in the transmission state. At the same time, the same operation as the left turn described above is performed, and the aircraft gradually turns to the left. Further, when the operation amount to the right side of the turning lever 77 increases and the operation pressure of the slow turning clutch 46 becomes high, the same operation as the right turning operation is performed, and the aircraft turns to the left.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the brake turning position will be described.
When the turning mode switch 78 is operated to the brake turning position and the turning lever 77 is operated rightward from the straight travel command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a and the unload valve 70 is switched to the cut-off position 70a, and hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is cut off. The hydraulic oil is operated to the right turning clutch 49 in the transmission state. In this case, since the left turning clutch 49 is in a semi-transmission state, the aircraft gradually turns to the right. The control state of the control device 64 at this time corresponds to the low-speed turning process for the brake turning mode.

  When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil begins to be supplied to the reverse rotation clutch 53 via the control valve 72 (reverse rotation position 72c), and is proportional as the rotation lever 77 is moved to the right in the direction away from the straight command position after leaving the dead zone. The operating pressure of the reverse clutch 53 is increased by the control valve 71. However, even if the turning lever 77 is operated rightward to the maximum operation position Rm at this time, the operation pressure of the reverse clutch 53 does not reverse the transmission shaft 44 but stops the rotation of the transmission shaft 44 or substantially. The operating pressure is adjusted so as to stop.

  In this case, the power from the left side clutch 34 (left occlusal portion 33L) and the braking force of the transmission shaft 44 braked via the reverse clutch 53 are simultaneously transmitted to the right output gear 32R. Therefore, in the range where the operating pressure of the reverse clutch 53 is low, the power from the left side clutch 34 (left occlusion portion 33L) overcomes the braking force of the reverse clutch 53 and the left side clutch 34 (left occlusion) The right output gear 32R is driven by the power from the portion 33L). As a result, when the operating pressure of the reverse rotation clutch 53 is low, the aircraft gradually turns to the right (corresponding to the low-speed turning process for the brake turning mode).

  When the amount of movement of the swivel lever 77 to the right increases and the operating pressure of the reverse clutch 53 reaches an operating pressure set to act as a brake, the braking force is applied to the left side clutch 34 (the left occlusal portion 33L). ), The right output gear 32R enters the braking state, and the aircraft turns to the right. The turning state at this time corresponds to a brake turning state in which the rotation of the traveling device inside the turning is stopped or substantially stopped.

  Accordingly, as the operation pressure of the reverse clutch 53 is increased by the proportional control valve 71 in accordance with the operation of the turning lever 77, the transmission shaft 44, the transmission gear 48, the turning clutch case 47, and the right turning clutch 49 are moved. Thus, a braking force is applied to the right output gear 32R. That is, the pseudo brake state is equal to the state in which the transmission shaft 44 is braked by the brake.

  When the turning lever 77 is operated to the left from the rectilinear command position N to move out of the dead zone, the left turning control valve 68 is operated to the supply position 68a, the unload valve 70 is operated to the cutoff position 70a, and the left side clutch 34 (the left occlusion portion 33L) and the left turning clutch 49 are supplied with hydraulic oil, the left side clutch 34 (the left occlusion portion 33L) is operated to be disconnected, and the left turning clutch 49 is supplied with hydraulic oil. Operated in transmission state. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the amount of movement of the turning lever 77 to the left increases and the operating pressure of the reverse clutch 52 becomes high, the same operation as the right turning operation is performed, and the aircraft turns to the left.

Next, the case where the turning lever 77 is operated to the turning command operation area when the turning mode switch 78 is operated to the reverse turning position will be described.
When the turning mode switch 78 is operated to the reverse turning position and the turning lever 77 is operated to the right from the rectilinear command position N to move out of the dead zone, the right turning control valve 67 is operated to the supply position 67a, and the unload valve 70 is switched to the cut-off position 70a, and hydraulic oil is supplied to the right side clutch 34 (right occlusion portion 33R) and the right turning clutch 49, and the right side clutch 34 (right occlusion portion 33R) is cut off. And the right turning clutch 49 is operated to the transmission state. In this case, since the left turning clutch 49 is in a semi-transmission state, the aircraft gradually turns to the right. The control state at this time corresponds to the low-speed turning process for the reverse turning mode.

  When the swivel lever 77 is operated rightward from the rectilinear command position N and moves out of the dead zone, the proportional control valve 71 and swivel switching are almost simultaneously with the right swivel control valve 67 being operated to the supply position 67a as described above. The hydraulic oil begins to be supplied to the reverse rotation clutch 53 via the control valve 72 (reverse rotation position 72c). The proportional control valve 71 moves the rotation lever 77 away from the dead zone command position and moves to the right side. The operating pressure of the reverse clutch 53 is increased. In this reverse turning state, when the turning lever 77 is operated rightward to the maximum operating position Rm, the operating pressure of the reverse clutch 53 causes the reverse rotation clutch 53 to be completely engaged and the transmission shaft 44 to move straightly to the transmission shaft 29. And adjusted to rotate in the opposite direction.

  As the operation pressure of the reverse clutch 53 is increased by the proportional control valve 71 in accordance with the operation of the turning lever 77, the power of the subtransmission transmission shaft 27 is transmitted to the transmission gears 51, 52, the reverse clutch 53, the transmission shaft. 44, the transmission gear 48, the turning clutch case 47, and the right turning clutch 49 are transmitted to the right output gear 32R as the rotational power in the direction opposite to that of the straight drive shaft 29.

  In this case, since the power from the left side clutch 34 (the left occlusal portion 33L) and the power from the reverse clutch 53 are simultaneously transmitted to the right output gear 32R, the operation pressure of the reverse clutch 53 is reached. In the low pressure range, the power from the left side clutch 34 (the left occlusion portion 33L) overcomes the power from the reverse clutch 53, and the power from the left side clutch 34 (the left occlusion portion 33L) The output gear 32R is driven. As a result, when the operating pressure of the reverse clutch 53 is in a low pressure range, the aircraft gradually turns to the right. The control state at this time corresponds to a low-speed turning process for the reverse turning mode described later.

  Then, when the amount of movement of the turning lever 77 to the right increases and the operating pressure of the reverse clutch 53 becomes high, the power from the reverse clutch 53 becomes the power from the left side clutch 34 (the left occlusal portion 33L). The right output gear 32R is driven by the power from the reverse clutch 53 by overcoming it. In this state, the right output gear 32R is driven in the reverse direction with respect to the left output gear 32L, and the aircraft turns to the right. The turning state at this time corresponds to a reverse turning state in which the traveling device inside the turning is driven so as to advance in the direction opposite to the aircraft traveling direction.

  Next, when the turning lever 77 is operated leftward from the rectilinear command position N, when the dead zone is removed, the left turning control valve 68 is operated to the supply position 68a, and the unload valve 70 is moved to the cutoff position 70a. The hydraulic oil is supplied to the left side clutch 34 (left occlusion portion 33L) and the left turning clutch 49, and the left side clutch 34 (left occlusion portion 33L) is operated to be disconnected, The hydraulic oil is operated in the transmission state to the swing clutch 49. At the same time, the same operation as described above is performed, and the aircraft gradually turns to the left. When the amount of movement of the turning lever 77 to the left increases and the operating pressure of the reverse clutch 53 becomes high, the same operation as in the case of turning right is performed, and the aircraft turns to the left.

  As shown in FIG. 5, the turning state changeover switch 81 is provided in the grip portion of the turning lever 77, and in the case of the gentle turning mode, the turning state changeover switch 81 is operated in a state where the turning lever 77 is operated to make a turn. When the push operation is performed, the turning switching control valve 72 is operated from the slow turning position 72a to the brake turning position 72b, and the above-described brake turning mode can be switched. This brake turning mode is only while the turning state changeover switch 81 of the turning lever 77 is being pressed, and when the release operation is performed by releasing the turning state changeover switch 81 of the turning lever 77, the mode returns to the gentle turning mode.

  In the case of the brake turning mode, if the turning state changeover switch 81 of the turning lever 77 is pushed while the turning lever 77 is operated to turn, the operation pressure to the reverse clutch 53 is changed and adjusted. Reversing turning mode is entered and the aircraft turns. This reverse turning mode is only while the turning state changeover switch 81 of the turning lever 77 is being pressed. When the turning state release switch 81 of the turning lever 77 is released and returned, the brake turning mode is restored.

  Therefore, in this embodiment, the turning mode switch 78 and the turning state changeover switch 81 correspond to the turning mode command means 300. The turning radius command means 200 and the turning mode command means 300 constitute traveling drive state selection means for selecting and commanding any one of the straight drive state, the brake turning state, and the reverse turning state.

Next, the contents of control by the control device 64 will be described.
When the reverse drive state is commanded by the traveling drive state selection means, the control device 64 adjusts the proportional control valve 71 so that the operation pressure of the reverse rotation clutch 53 becomes the reverse rotation operation pressure. And when the brake turning state is commanded, a brake turning process for adjusting the proportional control valve 71 to adjust the operation pressure of the reverse rotation clutch 53 to the brake turning operation pressure is executed. In addition, as the brake turning process, the target operation pressure setting process for setting the target operation pressure as the brake turning operation pressure, and the proportional control valve 71 is controlled so that the operation pressure of the reverse clutch 53 becomes the target operation pressure. It is determined whether or not the traveling drive means 100 is in the brake turning state based on the operation pressure adjustment processing to be performed and the detection information of the left and right axle rotation sensors 66R and 66L. A rake turning state determination process is configured to be executed, and as the target operation pressure setting process, immediately after switching to a brake turning state command, a preset initial operation pressure is set as a target operation pressure, Thereafter, a process of setting a corrected operation pressure obtained by changing the pressure from the initial operation pressure as the target operation pressure until the brake turning state is determined to be determined by the brake turning state determination process is performed. Has been.

  When the explanation is added, the control device 64 is instructed when the turning mode command means 300 instructs the brake turning mode and when the turning radius command means 200 instructs the turning radius index that instructs the minimum turning radius. The brake turning state is determined to be instructed, the brake turning process is executed, the reverse rotation turning mode is instructed by the turning mode instruction means 300, and the turning radius instruction means 200 is instructed. When the turning radius index for instructing the minimum turning radius is instructed, it is determined that the reverse turning mode is instructed, and the reverse turning processing is executed.

Further, the control device 64 performs the brake turning state determination process when the rotational speed Vout of the traveling device outside the turn is equal to or higher than the determination condition switching set speed Vs5 based on the detection information of the left and right axle rotation sensors 66R and 66L. Is determined to be in the brake turning state if the rotational speed Vin of the traveling device inside the turn is less than the brake determination speed Vs2, and the rotational speed Vout of the traveling device outside the turn is used to switch the determination condition. When the speed is less than the set speed Vs5, the brake is applied if the speed ratio (Vout / Vin) of the rotational speed Vin of the traveling device inside the turn to the rotational speed Vout of the traveling device outside the turn is less than the set ratio (1/5). A process for determining that the vehicle is in the turning state is configured to be executed.

  The control device 64 sets the target operation pressure setting process as the initial operation pressure, and sets an operation pressure that is the lowest or close to an operation pressure within a range in which a variation in the brake turning operation pressure is predicted, and The correction operation pressure is configured to be executed in the form of setting an operation pressure obtained by gradually increasing the pressure from the initial operation pressure. For example, among the field conditions that are expected to change variously, for example, it is the lowest value at which a brake turning state can be obtained in a field that is most likely to be in a brake state, such as a dry paddy field where there is little slippage of the traveling device. The operating pressure is obtained from experimental results and the value is set as the initial operating pressure.

  Further, the control device 64 is instructed by the turning mode command means 300 to execute the brake turning mode, and the turning radius command means 200 is instructed by the turning radius index for instructing a turning radius larger than the minimum turning radius. In this case, as the operation pressure of the reverse rotation clutch 53, an operation pressure that is smaller than the initial operation pressure and becomes smaller as a larger turning radius is commanded by the turning radius index is set to be the operation pressure. The low-speed turning process for the brake turning mode for controlling the proportional control valve 71 is executed, the reverse turning mode is commanded by the turning mode command means 300, and the turning radius command means 200 is less than the minimum turning radius. When the turning radius index for instructing a large turning radius is instructed, the operation pressure for the reverse rotation clutch 53 is determined from the reverse rotation operation pressure. A low-speed turning process for the reverse turning mode for controlling the proportional control valve 71 so as to set an operation pressure that is small and becomes small as a turning radius is commanded by the turning radius index is set. It is configured.

  Specifically, the relationship between the operation position and the target operation pressure in the turning command operation area of the turning lever 77 constituting the turning radius command means 200 is determined by the amount of movement in the direction away from the straight-ahead command position in the turning command operation area. The larger the amount is, and the larger the amount of movement in the direction away from the rectilinear command position in the turn command operation region over the entire range of the turn command operation region, the greater the per unit amount of the operation position of the turn lever 77. It is determined as a relationship corresponding to a quadratic function that changes the amount of change in the target operation pressure with respect to the change to the large side, and in a direction away from the rectilinear command position in the turning command operation region defined as a relationship corresponding to this quadratic function Based on the relationship between the amount of movement and the target operating pressure, and the operating position of the turning lever 77, the eye corresponding to the operating position of the turning lever 77 Seeking operating pressure, and is configured to control the proportional control valve 71 to be the target operating pressures.

  As shown in FIG. 6, in the gentle turning mode, when the turning lever 77 is operated to the maximum operation position, the traveling device with the output rotational speed of the traveling device inside the turning of the pair of left and right traveling devices is on the opposite side. A target turning state in which the vehicle is decelerated to about 1/3 of the output rotation speed is set (see line L1 in FIG. 6). In the brake turning mode, the output rotation speed of the traveling device on the turning center side is zero. The target speed ratio is set (see line L2 in FIG. 6), and in the super faith turning mode, the output rotational speed of the traveling device inside the turn is in the direction opposite to the drive rotational direction of the opposite traveling device. A target speed ratio is set such that the speed is about 1/3 of the output rotational speed of the opposite travel device (see line L3 in FIG. 6).

  Then, as shown in FIG. 7, the operation position of the turning lever 77 and the target operating pressures of the slow turning clutch 46 and the reverse turning clutch 53 (specifically, in order to obtain the target speed ratio as described above, through experiments or the like in advance). , A target current supplied to the proportional control valve 71) is determined as a relationship corresponding to a quadratic function that changes the amount of change in the target operation pressure to the large side with respect to a change per unit amount of the operation position. Stored in the device 64.

  7A and 7B, the line L4 in FIG. 7 indicates the operation position of the turning lever 77 in the slow turning mode and the reverse turning mode, and the target operation pressure (the target current supplied to the proportional control valve 71) of the slow turning clutch 46 and the reverse clutch 53. 7 indicates a correlation between the operation position of the turning lever 77 and the target operating pressure (target current supplied to the proportional control valve 71) in the brake turning mode. .

  In the line L4, when the turning lever 77 is operated to the maximum operating positions Lm and Rm, in the slow turning mode, the slow turning clutch 46 is operated in a completely engaged state with a strong pressure contact force, and the reverse turning mode is set. In this case, the operation pressure is set so that the reverse rotation clutch 53 is operated in a completely engaged state by a strong pressure contact force (corresponding to the reverse rotation operation pressure). However, in the line L5, when the turning lever 77 is operated to the maximum operating positions Lm and Rm, the transmission shaft 44 is not driven in reverse rotation, but the turning of the traveling device 1 inside the turning is stopped or substantially stopped. The operating pressure in the reverse clutch 53 is set so as to be in a state. Therefore, the target operation pressure at the maximum operation position of the turning lever 77 in the line L5 corresponds to the initial operation pressure corresponding to the brake turning state.

Hereinafter, the turning control of the control device 64 will be described with reference to the flowcharts shown in FIGS. This process is repeated every unit time (5 msec).
If the turning lever 77 is within the dead zone of the straight travel command position N, the unload valve 70 is switched to the discharge position 70a (steps 1 and 2). Further, both the left turn control valve 68 and the right turn control valve 67 are held in the shut-off state (steps 3 and 4). When the turning lever 77 deviates from the dead zone from the straight travel command position N, the left turn control valve 68 is switched to the supply position 68a if the operation direction is the left direction, and the right turn control valve 67 is turned if the operation direction is the right direction. Switching to the supply position 67a (steps 5, 6 and 7), the unload valve 70 is switched to the shut-off position 70a (step 8).

  Next, a target operation pressure setting process is executed (step 9). As shown in FIG. 9, this target operation pressure setting process is performed as to whether or not the brake turning state is instructed, that is, the brake turning mode is instructed by the turning mode switch, and the turning lever is moved to the maximum operating positions Lm and Rm. Whether or not the target current corresponding to the commanded state has not been output immediately after the command of the brake turning state has been output, and the turning mode other than the brake turning mode is instructed. If it is, the target current corresponding to the turning mode and the operation position of the turning lever at that time is obtained (steps 21, 22, 23, 24). The reset process in step 23 is a process for resetting control information such as various correction contents of the target operating pressure in the brake turning state as described later.

  At this time, if the brake turning state is commanded, the maximum operation of the turning lever 77 based on the correlation set in the line L5 in FIG. 7 corresponding to the brake turning mode and the detection information of the turning lever sensor 80. The target operating pressure at the position, specifically, the target current for the proportional control valve 71 is obtained, and the target current is set as the target operating pressure. This value corresponds to the initial set pressure. Incidentally, the target current at this time is set to about 400 mA.

  When such a target current (target operation pressure) is set, an operation pressure adjustment process is executed based on the set target current (step 10). In this operation pressure adjustment process, as shown in FIG. 11, the output current is adjusted so that the output current output to the proportional control valve 71 falls within the target dead zone set with respect to the target current obtained by calculation. (Steps 51 and 52). Thus, by adjusting the output current in the feedforward process, a desired turning force corresponding to the operation position of the turning lever 77 can be obtained with as little time delay as possible.

  As described above, when the output current corresponding to the target current corresponding to the brake turning state is output to the proportional control valve 71, it is predicted that the brake turning state is set. It discriminate | determines by turning state discrimination | determination processing (step 11). That is, as shown in FIG. 10, based on the detection information of the left and right axle rotation sensors 66R and 66L, when the rotation speed Vout of the traveling device outside the turn is equal to or higher than the determination condition switching set speed Vs5 (100 cm / sec). If the rotational speed Vin of the traveling device inside the turn is less than the brake determination speed Vs2 (20 cm / sec), it is determined that the brake is in the turning state, and the rotational speed Vin of the traveling device inside the turn is used for the brake determination. If the speed is Vs2 or higher, it is determined that the brake is not turning (steps 41, 42, 44, 45).

  When the rotational speed Vout of the traveling device outside the turn is less than the setting speed Vs5 for switching the discrimination condition, the ratio of the rotational speed Vin of the traveling device inside the turn to the rotational speed Vout of the traveling device outside the turn (Vout If / Vin) is less than the set ratio (1/5), it is determined that the brake is turning, and if the speed ratio (Vout / Vin) is equal to or greater than the set ratio, it is determined that the brake is not turning. (Steps 41, 43, 44, 45). For example, when the rotational speed Vout of the traveling device outside the turn is, for example, 40 cm / sec and the rotational speed Vin of the traveling device inside the turn is less than 8 cm / sec, it becomes less than the set ratio. The setting ratio is not limited to 1/5, and may be implemented with appropriate changes such as a slightly smaller ratio.

  In the target operation pressure setting process, after a set time (100 msec) has elapsed since the target current corresponding to the brake turning state is output, it is determined that the brake turning state is determined in the brake turning state determination process. Since the target operation pressure at that time is appropriate, the target operation pressure is maintained (steps 22 and 26). If it is not determined that the brake is in the turning state, the brake turning state is instructed. If the rotational speed Vout of the traveling device outside the turn is equal to or higher than the extremely low speed state determination speed Vs1 (10 cm / sec) set to a speed lower than the determination condition switching setting speed Vs5, the target current at that time is set. Correction is made to increase the unit amount (1 mA), and the corrected target current is set as a target operation pressure corresponding to the correction operation pressure (step Up 26 to 30). Then, when the state that is not determined to be the brake turning state continues, the operation pressure obtained by gradually increasing the pressure from the initial operation pressure is set as the correction operation pressure by repeatedly executing the processing of steps 29 and 30. Thus, the target operation pressure setting process is executed.

  Further, once it is determined that the vehicle is in the brake turning state, but after that it is determined that the vehicle is not in the brake turning state, a process of moving and averaging the detected values of the left and right axle rotation sensors corresponding to the traveling device inside the turn is performed. It is determined that the rotational speed Vin of the traveling device inside the turn is equal to or higher than the determination threshold Vs3 (20 cm / sec) while preventing erroneous detection due to sudden fluctuation (steps 31 and 32), and the brake When the turning state is commanded, the rotational speed Vout of the traveling device outside the turning is equal to or higher than the low speed state determination speed Vs4 (40 cm / sec) set to a speed lower than the determination condition switching setting speed Vs5. If it discriminate | determines (step 33), it will correct | amend so that a target current may be reduced by setting amount (30mA), and the corrected target current is corresponded to correction | amendment operation pressure. It sets as a standard operating pressure (step 34, 35). This process corresponds to the set amount reduction process. If the rotational speed Vout of the traveling device outside the turn is less than the low speed state determination speed Vs4 when the brake turning state is commanded, the set amount reduction process is executed. Will not.

  Therefore, in this embodiment, the reverse rotation clutch 53 can be used to bring out the respective turning states of the brake turning state and the reverse turning state, and by controlling as described above, differences in field conditions, etc. Regardless of this, it is possible to appropriately set the brake turning state.

[Second Embodiment]
Next, a second embodiment of the turning control device for a work vehicle according to the present invention will be described. This embodiment is the same as the configuration of the first embodiment except that the configuration of the traveling drive means and the configuration of the control processing for adjusting the operating pressure of the friction hydraulic clutch are the same as the configuration of the first embodiment, so only the different configuration will be described. The description of the same configuration is omitted.

  In other words, in the second embodiment, the traveling drive means 100 is transmitted to the traveling device inside the turning of the pair of left and right traveling devices 1 as the plurality of turning states in the turning state. By changing the magnitude of the propulsive force traveling in the reverse direction with the reverse rotation clutch, the mode is switched to the slow turning state, the brake turning state, and the reverse turning state.

  Specifically, as shown in FIG. 12, only the reverse clutch 53 in the first embodiment is provided, and the slow turning clutch 46 in the first embodiment is deleted. Further, as shown in FIG. 13, since the slow swing clutch 46 is deleted, the flow path switching configuration is unnecessary, and the swing switching control valve 72 and the reverse rotation pilot valve 74 in the hydraulic unit 57 are deleted. It is the composition which becomes. Then, in each of the slow turning mode, the brake turning mode, and the reverse rotation mode, the drive pressure of the traveling device inside the turn is changed by adjusting the operation pressure of the reverse rotation clutch 53.

  That is, as shown in FIG. 14, as a correlation between the operation position of the turning lever 77 and the target operating pressure of the reverse clutch 53 (target current supplied to the proportional control valve 71), the slow turning mode, the brake turning mode, and Three types of lines L4 to L6 corresponding to each of the reverse turning modes are set. The reverse turning line L6 and the brake turning line L5 are the same as in the first embodiment. In the slow turning line L4, when the turning lever 77 is operated to the maximum operating positions Lm and Rm, The traveling device on the inside of the turn moves in the forward direction by the rotation operation force in the forward direction transmitted through the turning clutch 49 in which the rotational power for straight traveling is in a semi-transmission state, or by the accompanying rotation by contact with the ground The operating pressure is set so that a braking force sufficient to allow the rotation is applied and a pseudo slow turning state is obtained.

  Therefore, in this embodiment, each of the turning states of the slow turning state, the brake turning state, and the reverse turning state can be revealed by using one frictional hydraulic clutch.

[Another embodiment]
Hereinafter, other embodiments are listed.

(1) In the above embodiment, the turning mode command means 300 and the turning radius command means 200 as the travel drive selection means are separately provided. However, the present invention is not limited to this configuration, and the turning radius command means is The structure may also be used as the turning mode command means. In other words, the turning lever composing the turning radius command means switches from the straight command position to the turn commanding state, and the turn radius is continuously changed as the operation amount is increased. The turning state may be switched so as to sequentially switch to a certain region, a region where the brake is turning, and a region where the turning is reverse.

(2) In the above embodiment, as the turning mode command means, apart from the turning mode switch, a turning state changeover switch is provided in a state where a finger can be operated on the grip portion of the turning lever. It is good also as a structure which does not provide a selector switch.

(3) In the above-described embodiment, the turning radius command means includes a turning lever that can be freely moved over the straight command position and the turn command operation area. For example, a rotary operation dial or a plurality of push-operated switches It can implement with various forms, such as a structure provided with.

(4) In the above embodiment, a combine is shown as a work vehicle. However, the present invention can also be applied to agricultural work vehicles other than combine and other work vehicles.

Overall side view Diagram showing transmission configuration Diagram showing transmission configuration Hydraulic circuit diagram Control block diagram The figure which shows the correlation between the turning lever operation position and the target speed ratio The figure which shows the correlation between the turning lever operation position and the target operation pressure Flow chart of control operation Flow chart of control operation Flow chart of control operation Flow chart of control operation Diagram showing transmission configuration Hydraulic circuit diagram The figure which shows the correlation between the turning lever operation position and the target operation pressure

DESCRIPTION OF SYMBOLS 1 Traveling device 53 Friction type hydraulic clutch 64 Control means 66R, 66L Traveling speed detection means 71 Supply pressure adjusting means 100 Traveling drive means 200 Turning radius command means 300 Turning mode command means

Claims (6)

The driving state of the pair of left and right traveling devices is a straight drive state, the brake turning state in which the traveling device on the inside of the turn stops or substantially stops, and the reverse turning state in which the traveling device on the inside of the turn is driven to travel in the direction opposite to the advancing direction of the aircraft Traveling drive means switchable to,
Traveling drive state selection means for selecting and commanding any one of the straight drive state, the brake turning state, and the reverse turning state;
A work vehicle turning control device provided with control means for controlling the travel drive means so as to be in a selected drive state based on a command of the travel drive state selection means,
By changing the operating pressure of the friction-type hydraulic clutch that transmits the propulsive force that travels in the direction opposite to the aircraft traveling direction to the traveling device inside the turning of the pair of left and right traveling devices, the traveling drive means, It is configured to be switchable between the brake turning state and the reverse turning state,
An operating pressure adjusting means that adjusts an operating pressure of the friction type hydraulic clutch by changing and adjusting a supply pressure of pressure oil supplied from a hydraulic pressure source, and a pair of rotational speeds of the pair of left and right traveling devices that are detected separately. Traveling speed detection means,
The control means is
When the reverse rotation state is instructed by the travel drive state selection means, reverse rotation processing is performed for adjusting the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the reverse rotation operation pressure. And, when the brake turning state is commanded by the travel drive state selection means, the brake turning processing for adjusting the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the brake turning operation pressure. And is configured to perform
As the brake turning process, a target operation pressure setting process for setting a target operation pressure as the brake turning operation pressure, and the operation pressure adjusting means so that the operation pressure of the friction hydraulic clutch becomes the target operation pressure. An operation pressure adjustment process to be controlled and a brake turning state determination process for determining whether or not the traveling drive means is in the brake turning state based on detection information of the pair of traveling speed detection means are executed. And
As the target operation pressure setting process,
Immediately after the travel drive state selection means is switched from the straight drive state or the reverse turning state command to the brake turning state command, a preset initial operation pressure is set as the target operation pressure, and then Is configured to execute a process of setting a corrected operation pressure obtained by changing the pressure from the initial operation pressure as the target operation pressure until it is determined in the brake rotation state determination process that the vehicle is in the brake rotation state. ,
The control means, as the brake turning state determination processing,
Based on the detection information of the pair of traveling speed detecting means, when the rotational speed of the traveling device outside the turn is equal to or higher than the setting speed for determining condition switching, the rotational speed of the traveling device inside the turn is less than the brake determining speed. If there is, the brake turning state is determined, and if the rotational speed of the traveling device outside the turn is less than the determination condition switching set speed, the inside of the turning with respect to the rotational speed of the traveling device outside the turning is determined. A work vehicle turning control device configured to execute a process of determining that the vehicle is in the brake turning state when a speed ratio of a rotational speed of a traveling device is less than a set ratio . The control means is
The target operation pressure setting process is set as the initial operation pressure, the operation pressure that is the lowest in the range in which the fluctuation of the brake turning operation pressure is predicted or an operation pressure close thereto, and the correction operation pressure, 2. The turning control device for a work vehicle according to claim 1 , wherein the turning control device is configured to execute an operation pressure that is obtained by gradually increasing the pressure from the initial operation pressure. In the target operation pressure setting process, the control means,
After it is determined that the brake turning state is in the brake turning state determination process, and it is detected that the rotation speed of the traveling device inside the turn is equal to or higher than a determination threshold value, the corrected operation pressure at that time The turning control device for a work vehicle according to claim 2 , configured to execute an operation pressure lowering process for setting a value obtained by lowering a set amount as a target operation pressure. In the target operation pressure setting process, the control means,
When the travel drive state selection means is switched from the command for the straight drive state or the reverse rotation state to the command for the brake swing state, the rotational speed of the traveling device outside the turn is greater than the set speed for determination condition switching. 4. The turning control device for a work vehicle according to claim 3 , wherein the operation pressure lowering process is not executed if the speed is less than the low speed state determination speed set to a low speed. In the target operation pressure setting process, the control means,
When the travel drive state selection means is switched from the command for the straight drive state or the reverse rotation state to the command for the brake swing state, the rotational speed of the traveling device outside the turn is greater than the set speed for determination condition switching. If the speed is less than the extremely low speed determination speed set to a low speed, the initial operation pressure is set as the target operation pressure immediately after the travel drive state selection means is switched to the brake turning state command. After that, the work vehicle according to any one of claims 2 to 4 , wherein the work vehicle is configured not to execute a process of setting a corrected operation pressure obtained by changing a pressure from the initial operation pressure as the target operation pressure. Swivel control device. The travel drive state selection means is
A turning radius command means for commanding a turning radius index indicating a turning radius in the turning command state, which is freely switchable between a straight running command state for instructing straight running and a turning command state for instructing turning, and reverse to the brake turning mode. Comprising a turning mode command means for selecting and commanding the turning mode,
The control means is
When the turning mode command means instructs the brake turning mode, and the turning radius command means instructs the turning radius index to command the minimum turning radius, the brake turning state is instructed. And the processing for brake turning is executed, the reverse turning mode is instructed by the turning mode command means, and the turning radius index for instructing the minimum turning radius is instructed by the turning radius command means The reverse rotation mode is determined to be commanded, and the reverse rotation processing is executed, and
When the turning mode command means instructs the brake turning mode, and the turning radius command means instructs the turning radius index to command a turning radius larger than the minimum turning radius, the friction-type hydraulic pressure As an operation pressure of the clutch, an operation pressure that is smaller than the initial operation pressure and becomes smaller as a larger turning radius is commanded by the turning radius index is set, and the operation pressure adjusting means is set so as to obtain the operation pressure. The low-speed turning process for the brake turning mode to be controlled is executed, the reverse turning mode is commanded by the turning mode command means, and a turning radius larger than the minimum turning radius is commanded by the turning radius command means When a turning radius index is commanded, the operating pressure of the frictional hydraulic clutch is smaller than the operating pressure for reverse rotation and the turning radius index An operation pressure that decreases as a larger turning radius is commanded is set, and the low-speed turning process for the reverse turning mode for controlling the operation pressure adjusting means to perform the operation pressure is executed. Item 6. The turning control device for a work vehicle according to any one of Items 2 to 5 .

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