JP5125613B2 - Travel transmission for work vehicle - Google Patents

Description

The present invention relates to a travel transmission device for a work vehicle that changes a travel speed by automatically shifting an in-transmission transmission mechanism of a travel device by operation of a hydraulic device in a work vehicle such as a tractor.

Because mobile work machines such as tractors run at the optimal work speed by combining a main transmission that shifts in multiple stages or continuously and a sub-transmission that shifts in multiple stages such as high, medium, and low, In order to travel at the same work speed after the work is interrupted, the gear stage of the main transmission and the gear stage of the sub-transmission must be operated so as to satisfy the conditions before the work is interrupted. For the purpose of simplifying the shifting operation at the time of resuming the work, for example, as described in Japanese Patent Application Laid-Open No. 2007-225084, the shift position of the main transmission that has been used for the longest time is stored for each shift position of the sub-shift lever. Some have a shift function that automatically shifts to the shift position that has been used for the longest time before the operation is interrupted, without operating the main transmission only by shifting the sub-shift lever during re-running, that is, having a so-called memory shift function.
JP 2007-225084 A

In the work vehicle having the memory shift function, the main transmission is automatically shifted to the gear stage that has been used the longest when re-running. It is necessary to manually operate the gear position to the low speed side, which is troublesome.

Therefore, an object of the present invention is to automatically shift the starting speed at the time of resuming work to an arbitrary gear stage other than the memory shift in a work vehicle having a memory shift function.

The problems of the present invention are solved by the following technical means.
According to the first aspect of the present invention, there is provided a main shift speed storage means ( B ) for storing a main shift speed in which the main shift position relative to the sub shift position is used for the longest time during traveling, or a main shift speed immediately before stopping; a set gear stage memory means for storing the arbitrarily set to shift speed main gear-shifting position for the shift position (a), the control by the straight front gear position memory means (B) and set gear stage memory means (a) appropriately only setting the control switching means (C) is switched on, the set speed in the stage storage means (a) is capable of setting a different main gear stage at the forward side and the reverse side,
The control switching means (C) comprises an AT shift road switch (41) and an AT shift work switch (42), and the auxiliary shift is performed by the AT shift road switch (41) when the sub-shift is at a high speed position. The AT shift work switch (42) is used to switch the main shift when the sub-shift is in the middle / low speed position. When the AT shift road switch (41) or the AT shift work switch (42) is turned on, The automatic transmission is configured to shift to the main shift speed stored in the shift speed storage means (B), and when the AT shift road switch (41) or the AT shift work switch (42) is turned off, the set shift speed is set. The present invention is a traveling transmission device for a work vehicle characterized in that it automatically shifts to the main gear shift stage stored in the storage means (A) .

With this configuration, when the work is resumed after the work is interrupted, the control switching means C selects the previous shift speed storage means B to immediately return to the original work speed, or the set speed change speed storage means A selects the work. It is possible to easily travel at a speed different from the speed before the interruption, that is, a speed arbitrarily selected by the operator. Further, when the set gear stage storage means A is selected, the traveling speeds on the forward side and the reverse side can be made different, which can meet the preference of the operator.
Further, the control switching means C comprises an AT shift road switch 41 and an AT shift work switch 42. The sub-shift is performed by the AT shift on-road switch 41 when the sub-shift is at the high speed position, and the AT shift work switch 42 is performed when the sub-shift is at the middle / low speed position.
When the AT shift road switch 41 or the AT shift work switch 42 is turned on, the shift is automatically made to the main shift stage stored in the previous shift stage storage means B. When the AT shift road switch 41 or the AT shift work switch 42 is turned off, the shift is automatically made to the main shift speed stored in the set shift speed storage means A.

According to a second aspect of the present invention, the AT shift work switch (42) is operated, and the shift to the main shift stage stored in the immediately preceding shift stage storage means (B) or the setting is performed. The work vehicle according to claim 1, characterized in that an AT shift sensitivity dial (38) is provided which makes it possible to change the shift sensitivity to the shift stage of the main shift stored in the shift stage storage means (A) . This is a traveling gearbox.

With this configuration, by operating the AT shift work switch 42, the shift to the main shift stored in the previous shift stage storage means B or the main shift stored in the set shift stage storage means A is performed. The shift sensitivity to the shift stage can be changed. The shift sensitivity is changed by the AT shift sensitivity dial 38.

According to the first aspect of the present invention, at the time of resumption after work interruption, it is possible to immediately make the work speed familiar before the work interruption, or to slow down the work speed until it gets used to the work again. Can continue working safely. If the operability is improved and the control at the set gear position storage means A is selected when the operation is resumed, it is possible to easily use the operation of starting the forward operation slowly after moving fast once.

According to the invention of claim 2, the speed change sensitivity can be changed.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a tractor 1 as a working machine in which the present invention is implemented.
The tractor 1 has an engine 2 mounted on the front of the machine body, transmits the rotational power of the engine 2 to the transmission in the transmission case 3, and transmits the rotational power decelerated by the transmission to the front wheels 4 and the rear wheels 5. I am doing so. The area around the cockpit 6 on the fuselage is covered with a cabin 7.

As shown in FIGS. 2 and 3, a steering handle 8 is erected on the front side of the cockpit 6 inside the cabin 7, and a forward / reverse lever 9 is provided on the lower right side thereof. On the left side of the cockpit 6, a parking brake lever 10 and a first PTO transmission lever 11 and a second PTO transmission lever 12 for shifting the PTO shaft that outputs power to the work implement are arranged.

The lower floor of the steering handle 8 is provided with left and right brake pedals 56 and 57 for braking the left and right front and rear wheels 4 and 5, respectively, and all brake pedals 58 for simultaneously braking all the wheels. An accelerator pedal 13 to be controlled is provided. This accelerator pedal 13 is used to adjust the traveling speed.

If the left and right brake pedals 56 and 57 are stepped on at the same time, brake braking is performed and the main gear shift is shifted to the low speed side to cause the engine brake to act. Further, when the left and right brake pedals 56 and 57 are depressed beyond the predetermined limit depression amount, the engine speed is reduced and the forward / reverse switching clutch 101 and the high / low speed switching clutch 107 are neutralized to power the front and rear wheels 4 and 5. The transmission and the power transmission to the PTO output shaft may be cut off. At this time, if the left and right brake pedals 56 and 57 are operated in the direction to return, the engine rotation is restored, the power transmission to the front and rear wheels 4 and 5 and the power transmission to the PTO output shaft are restored, and then the brake is released. Like that.

On the front side of the steering handle 8, a front panel 14 is provided on which a meter panel 72 that displays a traveling speed and an operation panel 73 that displays a use status of a work machine and the like are arranged.
When the throttle lever 15 is erected on the right side of the cockpit 6 and is tilted forward from the foremost idling position, the rotation of the engine increases. The throttle lever 15 is used to set the engine speed during operation. Reference numeral 16 denotes a seesaw-type first engine rotation storage switch. When the switch is tilted upward, the first stored rotational speed is obtained. When the switch is tilted downward, the second stored rotational speed is obtained. When the finger is released, the position returns to the neutral position. Reference numeral 17 denotes a seesaw-type second engine rotation storage switch. When the switch is tilted upward, the rotational speed increases. When the switch is tilted downward, the rotational speed decreases, and the rotational speed when the switch is released is stored. To set the rotation speed, the first engine rotation storage switch 16 is tilted upward or downward, and the second engine rotation storage switch 17 is tilted upward or downward to increase or decrease the rotational speed. When released, the number of rotations at that time is stored.

Next to the throttle lever 15, an auxiliary transmission lever 18 is erected. The sub-shift lever 18 has three speeds of low speed, medium speed, and high speed and a shift position for traveling on the road, and the mechanical speed changer in the transmission case 3 is operated at low speed, medium speed, and high speed at three speeds of low speed, medium speed, and high speed. -Shifts at a high speed and the main shift can be shifted to eight stages, and at the road running position, the main gear can be shifted using a gear stage with three or more speeds at a high speed and the speed is suitable for road driving.

The main shift is a combination of high and low two-speed shifts by hydraulic control, as in the case of four-speed shifts by hydraulic control, and has a total of eight shift stages. The average vehicle speed by these shift stages is the low / medium of the sub-shift lever 18. Combined with high speed and high speed, there are a total of 24 shift stages. The shift stage of the main shift is changed by travel shift raising / lowering switches 33 and 34, which will be described later.

Reference numerals 19 and 20 are sub-control levers for taking out external hydraulic pressure, and are used when hydraulic oil is supplied to a hydraulic cylinder or the like of the working machine. 21 and 22 are spare sub-control lever mounting grooves. 23 is a draft ratio adjustment dial, which turns to the left when turned to the position side, reduces the amount of change in the working machine's lifting with respect to the load, reduces the tilling depth, and conversely turns to the right to become the draft side. The amount of change in the lifting and lowering of the work implement with respect to increases the plowing depth.

Reference numeral 24 denotes a lifting adjustment dial. When the dial 24 is turned counterclockwise, the rising height of the three-point link is lowered. Depending on the working machine, when it is raised to the highest level, when it hits the tractor body or when the working efficiency is better when it is not raised too much, the raising adjustment dial 24 adjusts. Reference numeral 25 denotes a tilt adjustment dial. When the dial is turned counterclockwise, the work implement rises to the right.

26 is a 4WD changeover switch, which has a travel loader, a super full turn, and a 2WD turn, and the travel loader automatically switches to 4WD when it becomes a muddy, steep hill or uneven road, usually 2WD. Even if the brake is applied or stopped during operation, the 4WD state is obtained. Two-WD is a rear-wheel two-wheel drive, and four-WD is a front-rear four-wheel drive. In the super full turn, the speed of the front wheel is increased by turning at the 4WD, and quick turning is possible, and in the 2WD turn, the driving of the front wheel is removed by turning at the 4WD and the rear wheel is turned by one brake. Quick and smooth turn in hard fields.

Reference numeral 27 denotes a horizontal cylinder raising / lowering switch which can move the horizontal cylinder of the three-point link and is used for attaching / detaching the work machine. Reference numeral 28 denotes a PTO switch. When the switch is pushed and turned to the right, the PTO clutch is engaged, and when pressed, the PTO clutch is automatically turned to the left and the PTO clutch is disengaged. 29 is a PTO automatic switch, which is manually turned when turned to the left and always rotates when the clutch is engaged, and automatically turned when turned to the right and stops rotating when the travel clutch is depressed or the three-point link is raised. This PTO automatic switch 29 is mainly used during paddy field work.

Reference numeral 30 denotes a diff lock switch. When it is pushed outward once, it becomes diff lock, and when it is pushed outward again, the diff lock is released. It cannot be pushed inward, but switches each time it is pushed outward.
31 is a working machine raising / lowering lever, the front side descends and the rear side rises. Reference numeral 32 denotes a work implement raising / lowering switch, which is raised to the uppermost position set by the raising adjustment dial 24 by pushing the rear side once, and lowered to the position set by the work implement raising / lowering lever 31 by pushing the front side once.

Reference numerals 33 and 34 denote travel shift raising / lowering switches for setting the start shift stage. Each time the travel shift increase switch 33 is pressed once, the start shift stage is shifted up, and every time the travel shift decrease switch 34 is pressed once, the start shift stage is set. Shift down. The travel shift raising / lowering switches 33 and 34 similarly change the starting shift stage upward with the sub-shift as a reference and the main shift as the third speed when the sub-shift lever 18 is driven on the road.

Reference numeral 36 denotes a switch box. When the lid is opened, various adjustment switches shown in FIG. 3 are arranged.
Reference numeral 37 denotes an ascending / descending monitor lamp for the work machine, which is lit and displayed when the work machine is raised and lowered. Reference numeral 38 denotes an AT shift sensitivity dial which changes the sensitivity to increase or decrease the vehicle speed when the AT work switch 42 is pressed to perform automatic shifting.

No. 39 is a descent speed dial that adjusts the descent speed of the work implement. When it is turned to the right, the work implement descends quickly, so it is used for light work implements. Conversely, turning it counterclockwise lowers the work implement slowly, so it is heavy. Used for work machines.

Reference numeral 40 denotes a travel brake adjustment dial, which adjusts the degree of application of the turning brake that acts when the auto brake on / off switch 48 is turned on.
The AT shift road switch 41 automatically shifts the main shift when traveling on the road, that is, the sub-shift is at a high speed, and the AT shift work switch 42 automatically shifts the main shift when traveling, that is, the sub-shift is at the middle / low speed, When the switch is turned on, the main shift is automatically shifted to the shift stage that has been used the longest last time according to the shift position of the sub shift lever 18, and when it is turned off, it is arbitrarily set according to the shift position of the sub shift lever 18 The gear shifts to the main gear. The AT shift road switch 41 and the AT shift work switch 42 correspond to the control switching means C of the present invention, and a flowchart of automatic control will be described in detail with reference to FIG.

43 is a connection sensitivity shift switch for the main shift, which changes the connection feeling when the main shift is shifted, and when the switch is turned on, the monitor is turned on and a gentle shift is performed. When the connection sensitivity shift switch 43 is turned off and a traction system such as a plow is operated, the shift connection time of the main transmission is shortened, and the operation can be performed lightly.

44 is a connection sensitivity PTO switch, which has a rotary, pasture 1 and pasture 2; when it is set to rotary, the connection of PTO becomes faster, and the rotary immediately turns with a rotational force that does not lose the resistance of soil. When it is set to 2, the connection of PTO becomes loose and it is used with pasture work machines and snow blowers.

45 is a horizontal sensitivity switch, and the operation sensitivity of the automatic horizontal control device changes. When the switch is pressed, the movement of the automatic horizontal control becomes slow, and when the switch is pressed again, it returns to the original state.
46 is a backup on / off switch, and when it is turned on, the work machine is automatically raised when the vehicle moves backward. 47 is an auto lift on / off switch, and when the handle is turned on, the work machine is automatically raised. 48 is an auto brake on / off switch, and when it is turned on and the handle is turned, only the rear wheel inside the turn is automatically braked.

Reference numeral 49 denotes a horizontal changeover switch. When the level is automatically leveled, the level sensor automatically holds the level. When the level is set manually, the tilt adjustment dial 25 can be adjusted. When the level is parallel, the three-point link is always parallel to the tractor body. When it is tilted, the three-point link maintains a constant tilt angle with respect to the ground.

Reference numeral 50 denotes a 3P changeover switch, which performs control changeover selection based on the lift cylinder mounting position to the three-point link.
Reference numeral 51 denotes an auto accelerator switch. When the work machine is raised in the on state, the engine speed decreases to 1700 rpm.

FIG. 4 is a diagram showing a driving force transmission mechanism, and a power transmission configuration from the engine 2 to the front wheels 4 and the rear wheels 5 will be described.
A gear 111 is fixed to an input shaft 110 directly connected to the output shaft of the engine 2 and a forward / reverse switching clutch 101 is mounted.

One gear 112 of the forward / reverse switching clutch 101 meshes with a gear 114 fixed to the first transmission shaft 113 and decelerates, and the other gear 115 of the forward / reverse switching clutch 101 is connected to the first transmission shaft 113 via a counter gear 117. Engage with the fixed gear 118 to transmit power in reverse. That is, when the forward / reverse switching clutch 101 is engaged (connected) to the gear 112 side, the rotation of the input shaft 110 is transmitted to the first transmission shaft 113 in the reverse direction, and when it is engaged to the gear 115 side, the rotation of the input shaft 110 is forward. The main clutch disengaged state can be maintained by controlling the hydraulic valve in the main clutch disengaged state where the neutral state separated from both the gear 112 and the gear 115 is disengaged from the power transmission. ing.

A first speed / three-speed switching first transmission clutch 102 and a second speed / four-speed switching second transmission clutch 103 are mounted on the first transmission shaft 113 on the lower transmission side of the forward / reverse switching clutch 101. That is, the gears 120 and 122 of the first transmission clutch 102 mesh with the gears 121 and 123 fixed to the second countershaft 119, and the first transmission shaft 113 is decelerated for the first speed or slightly increased for the third speed. Is transmitted to the second counter shaft 119. Further, the gears 124 and 126 of the second speed change clutch 103 are engaged with gears 125 and 127 fixed to the second counter shaft 119, and the first speed is increased slightly for the second speed or greatly increased for the fourth speed. The rotation of the transmission shaft 113 is transmitted to the second counter shaft 119.

A third counter shaft 129 is connected to the lower transmission side of the second counter shaft 119 by a coupling 128 to transmit the rotation as it is. A small gear 130 and a large gear 131 are fixed to the third counter shaft 129. The small gear 130 and the large gear 131 are engaged with the large gear 133 and the small gear 134 of the high / low speed switching clutch 107 mounted on the second transmission shaft 132, respectively, and the third counter shaft 129 rotates at a high speed or a low speed. It is transmitted to the shaft 132.

A gear 136 is fixed to the lower transmission side end portion of the second transmission shaft 132, and the gear 136 and the large gear 138 of the large and small gear 152 pivotally supported by the third drive shaft 143 are engaged with each other to reduce the transmission. Yes.

The small gear 139 of the large and small gears 152 meshes with the gear 137 of the double auxiliary transmission clutch 135 that is pivotally supported by the bevel gear shaft 142 and is transmitted at a reduced speed. Further, the gear 141 provided integrally with the gear 137 is meshed with the large gear 144 fixed to the fifth counter shaft 216 for transmission at a reduced speed.

A small gear 145 is further fixed to the fifth counter shaft 216, and the small gear 145 meshes with the large gear 140 of the double sub-transmission clutch 135 to be further decelerated. Accordingly, the rotation of the second transmission shaft 132 is transmitted while being sequentially decelerated in the order of gear 136 → large gear 138 → small gear 139 → gear 137 → gear 141 → large gear 144 → small gear 145 → gear 140.

The shifters 217 and 218 of the double auxiliary transmission clutch 135 are engaged with the bevel gear shaft 142 so as to be slidable in the axial direction. When the shifter 217 is slid and engaged with the gear 137, the rotation of the gear 137 is applied to the bevel gear shaft 142. Then, when the shifter 218 is slid and engaged to the gear 141 side, the rotation of the gear 141 is transmitted to the bevel gear shaft 142, and the bevel gear shaft 142 is rotated at a low speed.

The rotation of the bevel gear shaft 142 is transmitted to the differential gear 219 via the bevel gears 148 and 149, and is transmitted from the differential gear 219 to the rear wheel 5 via the axle 56 and the planetary gear 151.
To summarize the above description, the rotation of the input shaft 110 is first switched to forward rotation or reverse rotation by the forward / reverse switching clutch 101, and the first speed / three-speed switching first shift clutch 102 and the second / fourth-speed switching first gear 102 are switched. The gears are shifted to the fourth speed by the two-speed clutch 103, are shifted to the second speed by the high / low speed switching clutch 107, are further shifted to the third speed by the double auxiliary transmission clutch 135, and are transmitted to the bevel gear shaft 142. That is, the rotation of the input shaft 110 is shifted to 4 × 2 × 3 = 24 speeds and transmitted to the axle 150.

The transmission to the front wheel 4 is transmitted as follows. A gear 147 is fixed to the bevel gear shaft 142, and the gear 147 is engaged with a gear 146 fixed to the third drive shaft 143 via the relay gear 190 to drive the third drive shaft 143. The third drive shaft 143 is connected by a coupling 170 to a transmission shaft 160 to which a front wheel speed increasing clutch 163 is attached. Gears 167 and 168 of the front wheel speed increasing clutch 163 are engaged with gears 165 and 166 fixed to the seventh counter shaft 164 so as to switch from normal front wheel driving to front wheel speed increasing. When the front wheel acceleration clutch 163 is neutral, the driving of the front wheels 4 is cut off and only the rear wheels are driven.

The seventh counter shaft 164 is connected to the front wheel drive shaft 169 by a coupling 191, and is further connected to the front wheel drive bevel shaft 171 by a coupling 192, an extension shaft 194 and a coupling 193.

The power of the front wheel drive bevel shaft 171 drives the front wheel 4 via the bevel gears 172 and 173, the differential gear 174, the bevel gears 175 and 176, the vertical shaft 177, the bevel gears 178 and 179, and the planetary gear 180.

Next, the flow of the control signal will be described with reference to the control block diagram of FIG.
First, the engine controller 60 receives the exhaust temperature from the engine exhaust temperature sensor 61, the engine speed from the engine rotation sensor 62, the engine lubricating oil pressure from the engine oil pressure sensor 63, and the engine water temperature sensor 64. The temperature of the cooling water enters, the pressure of the common rail enters from the rail pressure sensor 55, a drive signal is output to the fuel pump 66, and a fuel supply adjustment control signal is output to the high pressure injector 65.

Next, the work implement elevating controller 67 includes an operation signal of the work implement elevating sensor 59 provided on the work implement elevating lever 31, an elevating signal of the lift arm sensor 68, a raising position restriction signal of the raising adjustment dial 24, and a lowering speed dial 39. A descending speed setting signal is input, and a work implement elevating signal is output to the main elevating solenoid 69 and the main descending solenoid 70 to operate the work implement elevating cylinder 71.

The engine controller 60, the work implement elevating controller 67, and a travel system controller 87, which will be described later, communicate with each other, and the engine panel, the elevating state of the work implement, the travel speed of the travel device, and the like are displayed on the meter panel 72. The operation position of each lever and pedal is displayed on the panel 73.

The travel system controller 87 incorporates a set shift speed storage means A and a previous shift speed storage means B of a control flowchart described later, and a shift 1 clutch pressure sensor 74, a shift 2 clutch pressure sensor 75, and a shift 3 clutch pressure sensor 76, Clutch engagement signals are input from the shift 4 clutch pressure sensor 77, and clutch engagement signals are input from the high speed clutch pressure sensor 78, the low speed clutch pressure sensor 79, the forward clutch pressure sensor 80, and the reverse clutch pressure sensor 81, respectively. A shift operation position signal is input from the lever operation position sensor 82 and the auxiliary transmission lever operation position sensor 83, a mission oil temperature is input from the mission oil temperature sensor 85, and a brake pedal depression signal is output from the brake pedal operation position sensor 86. Enter the accelerator mode designation switch A mode switching signal is input from the switch 84, a turning angle of the front wheel 4 is input from the front wheel cutting angle sensor 100, a front wheel driving on / off signal is input from the front wheel drive switching switch 106, and the rear wheel driving shaft rotation sensor 104 is input. The rotational speed is inputted from the front wheel drive shaft rotation sensor 105, the set gear stage signal is inputted from the traveling shift increase switch 33 and the traveling shift decrease switch 34, and the upper / lower of the engine is changed from the accelerator upper limit change switch 52 and the accelerator lower limit change switch 53. The lower limit rotational speed is input, an accelerator instruction signal is input from the accelerator sensor 54 of the throttle lever 15, and a check signal is input from the check switch 99.

Further, an ON / OFF signal is input to the traveling system controller 87 from the AT shift road switch 41 and the AT shift work switch 42.
A traveling system controller 87 outputs a forward / reverse switching clutch switching signal to the forward / reverse switching solenoid 88, and a linear pressure boosting solenoid 89 outputs a hydraulic relief pressure adjustment signal for driving the forward / reverse switching solenoid 88 to connect the clutch. Shock is reduced, an on / off signal is output to the clutch solenoid 90, and a 1st or 3rd speed on / off is applied to the shift 1-3 switching solenoid 91 of the hydraulic cylinder that drives the 1st speed / 3rd speed switching first shift clutch 102. Signal is output, and a relief pressure adjustment signal for driving the first-speed / three-speed clutch is output to the shift 1-3 boost solenoid 92 to reduce the shock of clutch connection, and the second shift for the second-speed / four-speed switching. A second-speed or fourth-speed ON signal is output to the shift 2-4 switching solenoid 93 of the hydraulic cylinder that drives the clutch 103, and the shift 2-4 boost solenoid 94 is output. A high-speed clutch switching solenoid 95 and a low-speed clutch switching solenoid that actuate a hydraulic cylinder that drives a high / low speed switching clutch 107 by reducing a clutch connection shock by outputting a hydraulic relief pressure adjustment signal that drives a high-speed / four-speed clutch The high-speed clutch input signal and the low-speed clutch input signal are output to 96.

Further, the traveling system controller 87 outputs a front wheel drive switching clutch switching signal to the front wheel acceleration 4WD solenoid 97 and the front wheel constant speed 4WD solenoid 98 of the hydraulic cylinder that drives the front wheel acceleration clutch 163.

FIG. 6 is a flowchart of control.
In step S1, the data of each sensor and switches are read. In step S2, it is determined whether the accelerator upper / lower limit changing switches 52 and 53 are operated. If this determination is YES, in step S3, the upper limit engine speed or the lower limit engine speed in the current setting mode is changed according to the setting, and if NO, step S3 is skipped and the process proceeds to step S4.

In step S4, it is determined whether the accelerator operation is within the engine rotation change region. If this determination is YES, it is determined whether the accelerator change is being set in step S5. If NO, the stepping region in step S8 is operated for a long time. Judgment is made. If the determination in step S5 is YES, in step S6, the engine speed is increased / decreased in accordance with the engine load factor and the accelerator operation, and the transmission speed reduction ratio is increased / decreased, and the process proceeds to step S12. If NO, the engine speed is changed according to the accelerator operation in step S7, and the process proceeds to step S12.

If the determination in step S8 is YES, the transmission speed is changed in step S9, and the process proceeds to step S12. If NO, a determination is made in step S10 as to whether or not the loading area is operated for a short time. If the determination is YES, the transmission is decelerated in step S11, and if NO, both are left as they are before step S12.

In step S12, it is determined that there is a brake operation. If this determination is YES, the process proceeds to step S13, and if NO, the process returns as it is. In step S13, it is determined that there is an operation exceeding the brake regulation. If this determination is YES, the travel clutch is disconnected in step S14, and the process proceeds to step S15. If NO, the travel clutch is engaged and the transmission is decelerated in step S18. To return.

In step S15, it is determined whether the PTO clutch lever is in the disengaged position. If this determination is YES, the PTO clutch is disengaged in step S16, and if NO, the PTO clutch is engaged in step S17, and both are returned.

FIG. 7 is a storage control flowchart of the shift speed memory by operating the memory manual setting switch including the AT shift road switch 41 and the AT shift work switch 42.
In step S20, data of each sensor and switches are read. In step S21, it is determined whether the Mori manual setting switch is turned off. If this determination is YES, the current shift position (forward / reverse, main shift, sub-shift) is determined in step S22. The main shift memory position is changed to the current main shift position, and in step S23, the forward memory main shift position A is displayed in green and the reverse memory main shift position B is displayed in yellow on the meter panel 72 as shown in FIG. Then, the current main shift position is highlighted and the process returns. If the determination in step S22 is NO, step S22 is skipped, the process in step S23 is performed, and the process returns.

FIG. 9 is a control flowchart of the present invention. The shift stage of the main shift set by the operator by operating the travel shift increase switch 33 and the travel shift decrease switch 34 in step S30 is the set shift stage storage means A of the present invention. The main speed change memory A is stored in the main speed change memory A, travels at an arbitrary travel speed while appropriately changing the main shift speed in step S31, reads the running data from each sensor in step S32, and uses the longest main shift in step S33. The speed or the speed immediately before the stop is stored in the main speed change memory B which is the speed change speed storage means B of the present invention, and the travel is stopped and restarted in step S34. In step S35, it is determined whether the AT shift road switch 41 and the AT shift work switch 42, which are the control switching means C of the present invention, are turned on. If this determination is YES, the main gear shift stage is automatically shifted with the data in the main shift memory B in step S37, and the vehicle travels in step S38. If the determination in step S35 is NO, the main gear shift stage is automatically shifted based on the data in the main transmission memory A in step S36, and the vehicle travels in step S38.

The main shift speeds stored in the main shift memories A and B are different data depending on the high, medium and low speed shift positions of the sub-shift lever 18 and the forward / reverse position of the forward / reverse lever 9. Remember.

Further, the arbitrary shift speed of the main shift stored in the main shift memory A may be stored in a state where the sub shift lever 18, the forward / reverse lever 9, and the main shift are set to the shift speed.
FIG. 10 is a control flowchart of automatic shift according to the depression amount of the accelerator pedal 13.

In step S40, the data of the sensor 54 is read. In step S41, it is determined whether the depression amount of the accelerator pedal 13 is 60% or more of the total depression amount. If this determination is YES, the engine speed is fixed at the maximum speed in step S43 and only the main gear shift stage is automatically shifted, and if the determination is NO, engine speed and main gear shift stage are determined in step S42. Both are automatically shifted, and the vehicle travels on the road or work place in step S44.

When the depression amount of the accelerator pedal 13 reaches 60% of the total depression amount, the operator may be informed that the control has changed by increasing the depression load of the accelerator pedal 13 or the like.

In addition, a setting change unit may be provided that allows the maximum engine speed in step S43 to be changed to, for example, 100% and 70% of the maximum possible output.

It is the whole tractor side view. It is an expansion perspective view around the cockpit of a tractor. It is a front view of a switch box. It is a power transmission diagram of a mission case. It is a block diagram of control. It is a flowchart figure of control. It is a flowchart figure of control. It is a front view of a meter panel. It is a flowchart figure of control. It is a flowchart figure of control.

A set gear position storage means (main shift memory A)
B Previous shift speed storage means (main shift memory B)
C Control switching means (AT shift road switch 41, AT shift work switch 42)
38 AT shift sensitivity dial
41 AT shift road switch
42 AT shift work switch

Claims (2)

The main shift position in which the main shift position relative to the sub shift position is used for the longest time during traveling, or the immediately preceding shift position storing means (B) for storing the main shift position immediately before the stop, and the main shift position relative to the sub shift position are arbitrarily set a set gear stage memory means for storing gear position set (a), the straight front gear stage memory means (B) and set gear stage memory means suitably switches control switching means a control by the (a) and (C) setting only the set speed in the stage storage means (a) is capable of setting a different main gear stage at the forward side and the reverse side,
The control switching means (C) comprises an AT shift road switch (41) and an AT shift work switch (42), and the auxiliary shift is performed by the AT shift road switch (41) when the sub-shift is at a high speed position. The AT shift work switch (42) is used to switch the main shift when the sub-shift is in the middle / low speed position. When the AT shift road switch (41) or the AT shift work switch (42) is turned on, The automatic transmission is configured to shift to the main shift speed stored in the shift speed storage means (B), and when the AT shift road switch (41) or the AT shift work switch (42) is turned off, the set shift speed is set. A traveling speed change device for a work vehicle, characterized in that it automatically shifts to a main speed shift stage stored in a storage means (A) . By operating the AT shift work switch (42), the shift to the main shift stored in the previous shift speed storage means (B) or the set shift speed storage means (A) is stored. 2. The traveling speed change device for a work vehicle according to claim 1 , wherein an AT shift sensitivity dial (38) is provided which makes it possible to change the shift sensitivity to the main shift speed.

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