JPH1044812A - Travel-speed change structure for work wagon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically shift main change gears to their appropriate shift positions when an auxiliary change gear is shifted to its lower-speed position or higher-speed position which are arranged in series in a travel-speed change structure for a work wagon so as to be shifted to plural gears. SOLUTION: The shift positions of main change gears 10 and 11 when an auxiliary change gear 12 has shifted from its lower-speed position to higher- speed position or from its higher-speed position to lower-speed position are stored as their first shift positions or as their second shift positions respectively. When the auxiliary change gear 12 is thereafter shifted from its higher-speed position to lower-speed position or from its lower-speed position to higher-speed position, the main change gears 10 and 11 are automatically shifted to their first shift positions or to their second shift positions respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling speed change structure for a working vehicle.

[0002]

2. Description of the Related Art Some work vehicles have a main transmission and an auxiliary transmission that can be shifted in a plurality of stages for traveling and are arranged in series. The main transmission and the auxiliary transmission are connected by a shift lever or the like. The gears can be operated independently of each other.
Thus, for example, if the main transmission is configured to be able to shift to eight speeds and the subtransmission is configured to be able to shift to two speeds, for example, the subtransmission is operated to shift to a low speed position, and the main transmission is shifted to five speeds.
Even if the sub transmission is shifted from the low speed position to the high speed position in a state where the shift operation is performed to the high speed shift position, the main transmission is left at the fifth speed shift position. Conversely, even if the sub-transmission is shifted from the high-speed position to the low-speed position, the main transmission remains at 5
Left in the high speed shift position.

[0003]

In an agricultural tractor, which is an example of a work vehicle as described above, for example, during plowing work in a narrow field, the body is advanced from one end of the field to the other end. It is said that plowing is performed while reaching the other end of the field, without turning the aircraft, the aircraft is moved backward as it is, returns to one end of the field, and performs plowing while advancing the aircraft again. In some cases, a work mode in which various operations are repeated is adopted.

In such a working mode, during the plowing operation while moving forward, the sub-transmission is operated to shift to the low-speed position, and the main transmission is shifted to the high-speed shift position (for example, the sixth or seventh speed shift position). When the vehicle shifts backward, the sub-transmission is shifted to the high-speed position, and the main transmission is shifted to the medium-speed shift position (for example, the third-speed shift position). In general, the low speed position of the auxiliary transmission is for traveling on a field, and the high speed position of the auxiliary transmission is for traveling. When traveling on a field, the main transmission is shifted to a middle or low speed shift position at the high speed position of the auxiliary transmission, and when traveling on a road, the main transmission is operated at the high speed position of the auxiliary transmission. The shift operation is often performed at a high speed shift position.

[0005] With this, during the plowing operation while moving forward and when the vehicle is moving backward, every time the sub-transmission is shifted to the low-speed position and the high-speed position, the main transmission is moved to the high-speed transmission position and the medium-speed (or low-speed) position. Since it is necessary to perform a shift operation to the shift position, there is room for improvement in operability of the shift operation. SUMMARY OF THE INVENTION It is an object of the present invention to cope with a work mode in which a shift position of a main transmission used differs between a low speed position and a high speed position of a subtransmission in a traveling speed change structure of a work vehicle.

[0006]

[Means for Solving the Problems]

[I] In a work mode in which the shift position of the main transmission at the low-speed position and the high-speed position of the sub-transmission is different and the sub-transmission is repeatedly shifted to the low-speed position and the high-speed position, the worker When shifting the transmission from the low-speed position to the high-speed position, the operator shifts the main transmission to a shift position suitable for the state of the low-speed position of the sub-transmission. When the shift operation is performed from the position to the low speed position, the operator shifts the main transmission to a shift position suitable for the state of the high speed position of the auxiliary transmission.

According to the first aspect of the present invention, when the operator shifts the speed of the auxiliary transmission from the low-speed position to the high-speed position, the shift position of the main transmission at the time of this shift operation (the low speed of the auxiliary transmission in the main transmission). Shift position suitable for the position state)
The main transmission is stored and updated as the first transmission position, and when the operator shifts the sub-transmission from the high-speed position to the low-speed position again, the main transmission is moved to the first transmission position (the low-speed of the sub-transmission in the main transmission). The shift operation is automatically performed to a shift position suitable for the position state.

Conversely, when the operator shifts the speed of the sub-transmission from the high-speed position to the low-speed position, the shift position of the main transmission at the time of this shift operation (the main transmission is suitable for the state of the high-speed position of the sub-transmission). The shift position) is stored and updated as the second shift position. When the operator shifts the sub-transmission from the low-speed position to the high-speed position again, the main transmission shifts to the second shift position (in the main transmission). The shift operation is automatically performed to a shift position suitable for the state of the high speed position of the auxiliary transmission.

As described above, when the operator shifts the speed of the auxiliary transmission to the low speed position using the second artificial operation tool, the main transmission can be operated at the low speed position of the auxiliary transmission without operating the first artificial operation tool. Is automatically shifted to the first shift position suitable for the state of the above. When the operator shifts the sub-transmission to the high-speed position with the second artificial operation tool, the first artificial operation tool is not operated. Also, the main transmission is automatically shifted to the second transmission position suitable for the high-speed position of the auxiliary transmission.

In this case, at the low speed position of the auxiliary transmission, the operator can take the first
If the main transmission is shifted by the manual operation device, when the sub-transmission is shifted from the low-speed position to the high-speed position thereafter, the shift position of the main transmission after the shift operation is changed to the new first shift position (main shift position). The transmission is stored and updated as a new shift position suitable for the state of the low speed position of the auxiliary transmission. Conversely, if the operator shifts the main transmission with the first artificial operation tool in response to changes in the state of the field or the work state at the high-speed position of the sub-transmission, then the sub-transmission is moved from the high-speed position to the low-speed position. When the shift operation is performed, the shift position of the main transmission after the shift operation is stored and updated as a new second shift position (a new shift position suitable for the high-speed position of the sub-transmission in the main transmission). Is done.

[II] According to the feature of the second aspect, similar to the case of the first aspect, the present invention has the "action" described in the above-mentioned [I], and additionally has the following "action". ing. Generally, the low speed position of the auxiliary transmission is for work traveling,
The high speed position of the auxiliary transmission is for traveling. At the time of traveling and traveling in the workplace, the main transmission is shifted to a middle or low speed shift position at the high speed position of the auxiliary transmission, and when traveling on the road, the main transmission is operated at the high speed position of the auxiliary transmission. The shift operation is often performed at a high speed shift position.

Thus, if the high-speed shift position is stored as, for example, the second shift position (the shift position suitable for the state of the high-speed position of the sub-transmission in the main transmission), the worker can change the sub-shift in the work place. When the shift operation is performed from the low speed position to the high speed position, the main transmission is automatically shifted to the high speed shift position (second shift position). It will be. According to the second aspect of the present invention, when the operator shifts the speed of the auxiliary transmission from the low-speed position to the high-speed position, the shift operation of the main transmission to the high-speed shift position is prevented, so that the above-described check is prevented. Such a shock at the time of the shifting operation does not occur.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) FIG. 1 shows the inside of a transmission case 8 of a four-wheel drive type agricultural tractor, which is an example of a work vehicle, and an engine 1
Is transmitted to the PTO shaft 4 via the transmission shaft 2 and the hydraulic multi-plate PTO clutch 3. The power from the engine 1 is supplied to the forward clutch 5 or the reverse clutch 6, the cylindrical shaft 7,
The power is transmitted to the left and right rear wheels 14 via the first main transmission 10, the second main transmission 11, the auxiliary transmission 12, and the rear wheel differential 13. The power branched immediately before the rear wheel differential device 13 is transmitted to the transmission shaft 15, a hydraulic clutch type front wheel transmission 16,
The power is transmitted to the left and right front wheels 19 via the front wheel transmission shaft 17 and the front wheel differential device 18.

The forward clutch 5 and the reverse clutch 6 are of a hydraulic multi-plate type combining a friction plate (not shown) and a piston (not shown), and are operated to the transmission side by supplying hydraulic oil. When the forward clutch 5 is operated to the transmission side,
The power of the engine 1 flows directly from the forward clutch 5 to the cylindrical shaft 7, and the aircraft advances. When the reverse clutch 6 is operated to the transmission side, the power of the engine 1 is transmitted to the cylindrical shaft 7 in a reverse rotation state via the reverse clutch 6 and the transmission shaft 20, and the body moves backward.

The first main transmission 10 includes four hydraulic multi-plate type first-speed clutches 21, second-speed clutches 22, and third-speed clutches 2.
It is configured as a hydraulic clutch type in which third and fourth speed clutches 24 are arranged in parallel and can be shifted to four speeds. By operating one of first to fourth speed clutches 21 to 24 to the transmission side, The power from the cylindrical shaft 7 on the engine 1 side is transmitted to the transmission shaft 25 on the lower side by performing a speed change operation in four steps.

The second main transmission 11 is also of a hydraulic clutch type in which two hydraulic multi-plate low-speed clutches 26 and high-speed clutches 27 are arranged in parallel, and one of the low-speed and high-speed clutches 26, 27 is transmitted. , The power from the transmission shaft 25 on the first main transmission 10 side becomes
The transmission is operated in two steps and transmitted to the auxiliary transmission 12 on the lower side. The auxiliary transmission 12 is of a synchromesh type that slides the shift member 53 and is capable of shifting in two stages, and is mechanically operated by a shift lever 28 described later.

(2) Next, forward and reverse clutches 5, 6,
A hydraulic circuit for the first and second main transmissions 10, 11 and the like will be described. As shown in FIG. 3, in the oil passage 30 from the pump 29, an electromagnetic proportional valve 35 for the forward and reverse clutches 5, 6 and pilot-operated switching valves 36a, 37a,
Pilot-operated switching valves 31a, 32a, 33 for first to fourth-speed clutches 21 to 24 of first main transmission 10
a, 34a, and electromagnetic proportional valves 38, 39 for the low-speed and high-speed clutches 26, 27 of the second main transmission 11, are connected in parallel.

An oil passage 40 branched from the oil passage 30 is provided with a hydraulic clutch 4 for a differential lock operation in the front wheel differential device 18.
1, a pilot-operated switching valve 42a for the rear wheel 1 and a hydraulic clutch 43 for a differential lock operation in the rear wheel differential device 13.
, A pilot operated switching valve 44a, a standard clutch 45 of the front wheel transmission 16, and a speed increasing clutch 46 (FIG. 1).
Pilot operated change-over valves 47a, 48
a are connected in parallel. Switching valves 31a to 34a,
36a, 37a, 42a, 44a, 47a, 48a
The spring is urged to the oil drain side (transmission blocking side), and is operated to the supply side (transmission side) by supplying the pilot hydraulic oil as described later.

A pilot oil passage 50 branches from the oil passage 30 via a pressure reducing valve 49, and the pilot oil passage 50 is connected to the switching valve 31.
a to 34a, 36a, 37a, 42a, 44a, 47
a, 48a, which are connected to solenoid operated valves 31b, 32b, 33b, 34b, 36b, 37.
b, 42b, 44b, 47b, 48b are connected. Solenoid operated valves 31b to 34b, 36b, 37b, 42
The b, 44b, 47b, and 48b are urged by a spring toward the oil discharge side (transmission cutoff side), and when these are electrically operated to the supply side, the pilot hydraulic oil is switched to the switching valves 31a to 34a,
It is supplied to the operation units of 36a, 37a, 42a, 44a, 47a, 48a, and these are operated on the supply side (transmission side).

(3) Next, the forward and reverse clutches 5,
6, the configuration of the operation units such as the first and second main transmissions 10 and 11 will be described. As shown in FIGS. 3 and 2, an opening / closing valve 51 capable of draining the pilot hydraulic oil from the operating portions of the switching valves 36a, 37a of the forward and reverse clutches 5, 6 is provided, and the opening / closing valve 51 is closed by a spring. And a clutch pedal 52 for mechanically operating the on-off valve 51 to the open side is provided. At the base of the steering handle 58 of the front wheel 19, a forward / reverse lever 59 for transmitting an electric forward signal and a reverse signal is provided.

As shown in FIG. 2, a speed change lever 28 is swingably supported around a horizontal axis of a control section of the body, and slides a shift member 53 of the subtransmission 12 (see FIG. 1). The shift fork 54 and the speed change lever 28 are mechanically interlocked by a link mechanism 55, and the speed change lever 28 is moved to a neutral position N, a low speed position L, and a high speed position H.
The sub-transmission 12 is operated to shift to the position. A position sensor 70 for detecting the operation position of the shift lever 28 is provided.

A lock pin 56 is provided on the lateral side of the shift lever 28 so as to be able to move in and out, and an operation button 57 for operating the lock pin 56 to move in and out is provided above the shift lever 28. The lock pin 56 is urged to the protruding side by a spring (not shown) (the operation button 57 is also urged to the left protruding side on the paper surface), and the lock pin 56 is engaged with the guide plate 60 on the fixed side. As a result, the shift lever 28 is held at each of the neutral position N, the low-speed position L, and the high-speed position H. When the operation button 57 is pressed, the lock pin 56 is retracted, and the shift lever 28 can be operated to the neutral position N, the low speed position L, and the high speed position H.

A shift-up button 61 and a shift-down button 62 are vertically arranged on the left lateral side of the shift lever 28. As will be described later, when the shift-up button 61 and the shift-down button 62 are pressed once, one The shift-up signal and the shift-down signal are transmitted, and the shift operation of the first and second main transmissions 10 and 11 shown in FIG. 1 is performed.

As shown in FIG. 2, a seven-segment shift display portion 64 for displaying shift positions (first to eighth speeds) of the first and second main transmissions 10, 11 and a forward / reverse lever 59 by a forward / reverse lever 59. Forward lamp 65 and reverse lamp 6 indicating which of clutches 5 and 6 is being operated on the transmission side.
6. A neutral lamp 67 for indicating that the shift lever 28 has been operated to the neutral position N is provided on the control unit. FIG.
As shown in FIG. 7, a pressure sensor 74 is provided for detecting whether the operating pressure of the forward and reverse clutches 5, 6 has reached a predetermined pressure in the transmission state, and the forward and reverse ramp 65 is detected by the detection of the pressure sensor 74. , 66 are turned on.

(4) Next, the shifting operation by the shift up button 61 and the shift down button 62 of the shift lever 28 will be described with reference to FIG. When the forward / reverse lever 59 shown in FIG. 2 is operated to the forward position F (step S1), an operation current is supplied to the electromagnetically operated valve 36b shown in FIG. 3 (step S2), and the switching valve 36a is operated to the supply side. Then, the forward clutch 5 is operated to the transmission side, and the forward lamp 65 is turned on (step S3). Reverse 5
9 is operated to the reverse position R (step S1),
An operation current is supplied to the electromagnetic operation valve 37b shown in FIG. 3 (step S4), the switching valve 37a is operated on the supply side, the reverse clutch 6 is operated on the transmission side, and the reverse lamp 66 is turned on (step S5). The buzzer 71 shown in FIG. 2 operates intermittently (step S6).

As shown in FIG. 1, the first main transmission 10
Since the gears can be shifted to the second gear and the second main transmission 11 can be shifted to the second gear, the first and second main transmissions 10 and 11 can shift the gear to eight gears. In this case, the second main transmission 1
In a state where the first low speed clutch 26 is operated to the transmission side, the first to fourth speed clutches 21 to 2 of the first main transmission 10 are set.
4 corresponds to the first to fourth shift positions, and the first to fourth speed clutches of the first main transmission 10 are in a state where the high speed clutch 27 of the second main transmission 11 is operated on the transmission side. 21 to 24 correspond to fifth to eighth shift positions.

As shown in FIG. 3, one of the first main transmissions 10
Each of the high-speed to fourth-speed clutches 21 to 24 and the low-speed and high-speed clutches 26 and 27 of the second main transmission 11 is provided with a pressure sensor 74 for detecting whether or not the operating pressure has reached a predetermined pressure in the transmission state. The current shift positions (first to eighth speeds) of the first and second main transmissions 10 and 11 are detected by the detection of the pressure sensor 74, and the detected shift positions are displayed on the shift display unit 64. Is performed (step S7).

In this state, it is assumed that the shift-up button 61 or the shift-down button 62 of the shift lever 28 has been pressed once (steps S8 and S9). In this case, as shown by the solid line A1 (time point B1) in FIG. 5, when the shift-up button 61 is pressed, the first main transmission 10 at the shift position one step higher than the current shift position is obtained.
When the operating current starts to be supplied to the solenoid operated valves 31b to 34b and the shift-down button 62 is pressed, the first main transmission in the shift position one step lower than the current shift position is performed. Ten solenoid operated valves 31b to 34b
Operation current starts to be supplied (step S1).
0).

At the same time, the solid line A2 in FIG. 5 (time B1)
As shown in FIG. 7, the electromagnetic proportional valves 38 and 39 of the low-speed or high-speed clutches 26 and 27 that are operated on the transmission side in the second main transmission 11 allow the low-speed or high-speed clutches 26 and 27 that are operated on the transmission side to be operated. The operating pressure is reduced from the operating pressure P2 in the transmission state to a predetermined low pressure P3 (step S11). In this case, at the time of the shift operation from the fourth shift position to the fifth shift position, the operating pressure of the low speed clutch 26 of the second main transmission 11 is reduced to zero, and the high speed clutch 2
The operation pressure of the operating pressure of the pressure 7 is increased from zero to a predetermined low pressure P3. Conversely, during a shift operation from the fifth gear position to the fourth gear position, the operating pressure of the high speed clutch 27 of the second main transmission 11 is reduced to zero, and the operating pressure of the low speed clutch 26 is reduced from zero to a predetermined low pressure. The operation is raised to P3.

Then, as shown by the solid line A1 (time B2 to time B3) in FIG.
1st to 4th speed clutches 21 to 2 on the high speed side or on the low speed side
The operating pressure of No. 4 is increased by the electromagnetic operating valves 31b to 34b to the operating pressure P1 in the transmission state. At the same time, as shown by the dashed line A3 in FIG. 5 (from time B2 to time B3), the shift-up button 6 of the first main transmission 10
1st to 4th before pressing the 1 or shift down button 62
The operating pressures of the speed clutches 21 to 24 are changed to the electromagnetic operation valves 31b to
The operation is lowered from the operating pressure P1 in the transmission state to zero by 34b (step S12).

Next, the second pressure maintained at the predetermined low pressure P3
The operating pressure of the low-speed or high-speed clutches 26, 27 of the main transmission 11 is gradually increased by the electromagnetic proportional valves 38, 39 as shown by the solid line A2 (time B3 to time B4) in FIG. The operating pressure of the low-speed or high-speed clutches 26, 27 reaches the operating pressure P2 in the transmission state (step S1).
3). In this case, from the time point B3 to the time point B4 of the solid line A2 shown in FIG. 5, the characteristic of increasing the operating pressure of the low-speed or high-speed clutches 26 and 27 is set for each shift position.
From the time point B3 to the time point B,
The operating pressure of 4 is rapidly increased in a short time.

As described above, the shift up button 6
One shift operation by pressing the 1 or shift-down button 62 is ended. When the shift operation is completed, the shift position after the shift operation is displayed on the shift display section 64 (step S14), and the buzzer 71 is operated once. And the end of the shift operation is notified to the operator (step S15). The shift operation as described above is not performed continuously even if the shift-up button 61 or the shift-down button 62 is kept pressed, and the shift-up button 61 or the shift-down button 62 is returned once and pressed again. Otherwise, the next one shift operation is not performed.

(5) Next, the shift operation of the subtransmission 12 by the shift lever 28 will be described. For example, the forward / reverse lever 59 is operated to the forward position F (the forward clutch 5 is operated to the transmission side and the reverse clutch 6 is operated to the transmission interruption side), and the shift lever 28 is operated to the low speed position L. In the state (operation button 57 and lock pin 56
When the shift lever 28 is held at the low-speed position L, the operation button 57 is pushed and the lock pin 56 is retracted from the guide plate 60. When the electromagnetically operated valve 36b shown in FIG. The forward clutch 5 is automatically operated to the transmission cutoff side by being operated to the oil drain side.

Thus, the shift lever 28 is operated from the low-speed position L to the neutral position N or the high-speed position H while the operation button 57 is pressed, and the operation button 57 is returned to operate the shift lever 28 by the lock pin 56. It is held at the neutral position N or the high-speed position H. In this case, when the operation button 57 is returned in the neutral position N, the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b, and the electromagnetic proportional valve 3
5, the forward clutch 5 is automatically operated to the transmission side immediately. When the operation button 57 is operated to return in the high-speed position H (low-speed position L), the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b, and the forward clutch 5 is automatically automatically moved to the transmission side by the electromagnetic proportional valve 35. Is operated.

In a state where the forward / reverse lever 59 is operated to the reverse position R (a state where the reverse clutch 6 is operated to the transmission side and the forward clutch 5 is operated to the transmission cutoff side), as described above, the shift lever 28 is operated. When the operation button 57 is pressed and returned, the reverse clutch 6 is automatically operated to the transmission blocking side and the transmission side as described above.

(6) Next, the shift lever 28 is moved to the low speed position L.
When the shift lever 28 is operated from the high speed position H to the low speed position L when the first and second main transmissions 10 and 11 are operated from the first shift position Y1 and the second shift position Y
Regarding the configuration in which the shift operation is automatically performed to the shift position Y2,
A description will be given based on FIG. 6 and FIG. First, when the engine 1 is started, an eighth speed shift position is set as the first shift position Y1, and a first speed shift position is set as the second shift position Y2 (step S21).

Thus, the low-speed position L of the transmission lever 28
When the shift lever 28 is operated from the low speed position L to the high speed position H in a state where the first and second main transmissions 10 and 11 are operated to shift to the eighth speed shift position (steps S22 and S22).
26), the first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first shift position) in the same manner as steps S10 to S15 in FIGS. 5 and 4. The second shift position Y2 (first shift position) is displayed on the shift display section 64 (steps S33 to S).
34).

Next, when the shift lever 28 is again operated from the high speed position H to the low speed position L (steps S22 and S26),
As in steps S10 to S15 of FIGS. 5 and 4, the first and second main transmissions 10 and 11 are moved to the first shift position Y1.
The shift operation is automatically performed to the (8th speed shift position), and the above-described first shift position Y1 (8th speed shift position) is displayed on the shift display section 64.
Is displayed (steps S30 to S31).

Conversely, when the first and second main transmissions 10 and 11 are shifted to the first speed shift position at the high speed position H of the shift lever 28, the shift lever 28 is operated from the high speed position H to the low speed position L. Then (steps S22 and S26),
As in steps S10 to S15 of FIGS. 5 and 4, the first and second main transmissions 10 and 11 are moved to the first shift position Y1.
The shift operation is automatically performed to the (8th speed shift position), and the above-described first shift position Y1 (8th speed shift position) is displayed on the shift display section 64.
Is displayed (steps S30 to S31).

Next, when the shift lever 28 is again operated from the low speed position L to the high speed position H (steps S22, S26),
As in steps S10 to S15 in FIGS. 5 and 4, the first and second main transmissions 10, 11 are moved to the second shift position Y2.
The shift operation is automatically performed to (the first-gear shift position), and the second shift position Y2 (the first-gear shift position) is displayed on the shift display portion 64.
Is displayed (steps S33 to S34).

As described above, the shift lever 28 is moved to the low speed position L.
, The first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first shift position), and the shift lever 28 is shifted from the high speed position H to the low speed position H. When operated to the position L, the first and second main transmissions 1
The state where 0, 11 is automatically shifted to the first shift position Y1 (8th shift position) is repeated.

(7) In the state of (6), for example, when the shift lever 28 is operated to the low speed position L (step S22) and the shift up button 61 and the shift down button 62 are pressed (step S23). , S
24), as in steps S10 to S15 in FIGS. 5 and 4 (refer to the preceding paragraph (4)) (step S25), the first and second main transmissions 10 and 11 are subjected to a shift operation, and after the shift operation, The shift positions of the first and second main transmissions 10 and 11 are displayed on the shift display section 64. After this, the shift lever 2
8 is operated from the low speed position L to the high speed position H (steps S22, S26), the shift positions of the first and second main transmissions 10, 11 at the time of this operation are stored and updated as the first shift position Y1. (Step S32).

In this case, for example, assuming that the fifth shift position of the first and second main transmissions 10 and 11 is stored and updated as the first shift position Y1, first the shift lever 28
Is operated from the low-speed position L to the high-speed position H, the first position is changed in the same manner as steps S10 to S15 in FIGS.
And the second main transmissions 10, 11 are in the second transmission position Y2.
The shift operation is automatically performed to (the first-gear shift position), and the second shift position Y2 (the first-gear shift position) is displayed on the shift display portion 64.
Is displayed (steps S33 to S34).

Next, when the shift lever 28 is again operated from the high speed position H to the low speed position L (steps S22 and S26),
The first and second main transmissions 10 and 11 are automatically shifted to the updated first shift position Y1 (fifth speed shift position) in the same manner as steps S10 to S15 in FIGS. 5 and 4. The updated first shift position Y described above is displayed on the shift display section 64.
1 (fifth speed shift position) is displayed (steps S30 to S30).
Step S31).

As a result, when the fifth shift position is stored and updated as the first shift position Y1, the shift lever 28
Is operated from the low-speed position L to the high-speed position H, the first and second main transmissions 10 and 11 are automatically shifted to the second transmission position Y2 (the first-speed transmission position), and the transmission lever 28 is moved. By operating from the high speed position H to the low speed position L, the first and second
The state where the main transmissions 10 and 11 are automatically shifted to the first shift position Y1 (the fifth shift position) is repeated.

(8) In the state of (6), for example, when the shift lever 28 is operated to the high-speed position H (step S22) and the shift-up button 61 and the shift-down button 62 are pressed (step S23). , S
24), as in steps S10 to S15 in FIGS. 5 and 4 (refer to the preceding paragraph (4)) (step S25), the first and second main transmissions 10 and 11 are subjected to a shift operation, and after the shift operation, The shift positions of the first and second main transmissions 10 and 11 are displayed on the shift display section 64.

Thereafter, when the shift lever 28 is operated from the high speed position H to the low speed position L (steps S22 and S2).
6), the first and second main transmissions 10 and 11 during this operation.
Is stored and updated as the second shift position Y2 (step S28). In this case, if the shift position of the first and second main transmissions 10 and 11 at the time of the above-described operation is on the high-speed side equal to or higher than the four shift positions (step S27), the first shift is performed.
And regardless of the shift position of the second main transmissions 10, 11
The third shift position is stored and updated as the second shift position Y2 (step S29).

In this case, for example, assuming that the third shift position of the first and second main transmissions 10 and 11 is stored and updated as the second shift position Y2, first, the shift lever 28
Is moved from the high-speed position H to the low-speed position L, the first position is changed in the same manner as in steps S10 to S15 in FIGS.
And the second main transmissions 10 and 11 are in the first transmission position Y1.
The shift operation is automatically performed to the (8th speed shift position), and the above-described first shift position Y1 (8th speed shift position) is displayed on the shift display section 64.
Is displayed (steps S30 to S31).

Next, when the shift lever 28 is again operated from the low speed position L to the high speed position H (steps S22 and S26),
The first and second main transmissions 10 and 11 are automatically shifted to the updated second shift position Y2 (third shift position) in the same manner as steps S10 to S15 in FIGS. 5 and 4. The updated second shift position Y is displayed on the shift display section 64.
2 (third speed shift position) is displayed (steps S33 to S33).
Step S34).

When the third shift position is stored and updated as the second shift position Y2, the shift lever 28
Is operated from the high-speed position H to the low-speed position L, the first and second main transmissions 10 and 11 are automatically shifted to the first shift position Y1 (the eighth shift position), and the shift lever 28 is moved. By operating from the low-speed position L to the high-speed position H, the first and second
The state where the main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (third speed shift position) is repeated.

As described above, the shift operation of the first and second main transmissions 10 and 11 is performed at the low speed position L and the high speed position H of the shift lever 28, and the shift lever 28 is moved from the high speed position H to the low speed position L. When the vehicle is operated from the low speed position L to the high speed position H, the first speed change position Y1 is stored and updated many times from the eighth speed change position to another speed change position. It is stored and updated many times from the first gear position to another gear position. In the above state, the engine 1 is stopped (step S35), and when the engine 1 is started again, the process returns to step S21, where the eighth shift position is set as the first shift position Y1, and the first shift position is set as the second shift position Y2. Is set.

[Another Embodiment of the Invention] As described above, the first and second shift positions Y1 and Y2 are stored and updated each time the shift lever 28 is operated to the low speed position L and the high speed position H. In contrast, regardless of the operation of the shift lever 28 to the low-speed position L and the high-speed position H, the first and second shift positions Y
The first and second shift positions (first shift position Y1) and the first shift position (second shift position Y2) are maintained without updating the first and second shift positions. May be.

The first and second main transmissions 10, 11 are 10
The present invention can also be applied to a work vehicle configured to be able to shift to one of six speeds and six speeds. The present invention is also applicable to a work vehicle configured to be able to shift to three speeds of a high speed position, a middle speed position, and a low speed position. The invention is applicable. In the configuration shown in FIG. 1, the first and second main transmissions 10 and 11 are configured as a hydraulic clutch type, but the first and second main transmissions 10 and 11 are connected to the auxiliary transmission 1.
2, the shift member may be configured to be a gear shift type in which the slide member is operated to be slid, and the shift member may be configured to be slid by a hydraulic cylinder to perform a shift operation.

[0054]

According to the first aspect of the present invention, in a traveling speed change structure of a work vehicle in which a main transmission and an auxiliary transmission that can be shifted to a plurality of speeds are arranged in series, a low speed position and a high speed position of the auxiliary transmission are provided. In the work mode in which the shift position of the main transmission is different, when the speed of the sub-transmission is operated by the second artificial operation tool, the main transmission is shifted to the first and second positions suitable for the low-speed position and the high-speed position of the auxiliary transmission. The shift operation is automatically performed to the second shift position, and the first manual operation device does not need to shift the main transmission to the first and second shift positions. Properties could be improved. In this case, the gear shift position of the main transmission when the gear shift operation is performed to the low-speed position and the high-speed position is performed without performing the special operation for setting the first and second shift positions. Since the first and second shift positions are automatically stored and updated, the first and second shift positions can be easily set and changed, and the operability is improved.

According to the features of claim 2, the "effect of the invention" of claim 1 is provided as in the case of claim 1. According to the feature of the second aspect, for example, even when a high-speed shift position is stored as the second shift position, when the operator shifts the sub-transmission from the low-speed position to the high-speed position, the main transmission is shifted to the high-speed side. The shift operation to the shift position is prevented from being restrained, and no shock occurs at the time of the shift operation, so that the riding comfort is improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a transmission system in a transmission case.

FIG. 2 is a diagram showing a linked state of a shift lever and an auxiliary transmission, a linked state of a shift display section and each section.

FIG. 3 is a hydraulic circuit diagram of the first and second main transmissions and the like.

FIG. 4 is a diagram showing a flow of a shift operation by a shift up button and a shift down button of a shift lever.

FIG. 5 is a diagram showing a state of each part at the time of a shift operation by a shift up button and a shift down button of a shift lever.

FIG. 6 is a diagram showing a first half flow when a shift operation is performed by a shift lever from a high speed position to a low speed position and from a low speed position to a high speed position.

FIG. 7 is a diagram showing a latter half flow when the speed change lever is operated to shift the subtransmission from a high speed position to a low speed position and from a low speed position to a high speed position.

[Explanation of symbols]

 10, 11 Main transmission device 12 Secondary transmission device 28 Second artificial operating device 61, 62 First artificial operating device L Low speed position of auxiliary transmission device H High speed position of auxiliary transmission device Y1 First transmission position Y2 Second transmission position

Claims (2)

[Claims] 1. A main transmission and a subtransmission that can be shifted in a plurality of speeds are arranged in series, and the first artificial operation device is operated based on the first artificial operation device that is manually operated. A shift control means for shifting the speed of the main transmission to a shift position to be shifted, and a second artificial operation tool for manually shifting the speed of the auxiliary transmission, and a second artificial operation tool. A first storage unit configured to store and update a shift position of the main transmission at the time of the shift operation as a first shift position each time the sub-transmission is shifted from a low-speed position to a high-speed position; Each time the sub-transmission is shifted from a high-speed position to a low-speed position by a two-man operating tool, a second storage position for storing and updating the shift position of the main transmission at the time of this shift operation as a second shift position. Means, and the first artificial operation tool When the speed of the auxiliary transmission is shifted to the low speed position by the second artificial operation tool while the main transmission is being shifted to a certain shift position, the stored first shift position is set. A first speed change means for automatically shifting the speed of the main transmission device in preference to the speed change control means; and a state in which the first manual operation device shifts the main transmission to a certain shift position. When the sub-transmission is shifted to a high-speed position by the second artificial operation tool, the main transmission is automatically controlled in preference to the transmission control means so as to be in the stored second transmission position. A traveling speed change structure for a working vehicle, comprising: a second speed change means for performing a speed change operation. 2. When the sub-transmission is shifted from a low-speed position to a high-speed position by the second artificial operation tool, the second transmission shifts the main transmission to a high-speed shift position. 2. The traveling speed change structure for a work vehicle according to claim 1, further comprising a restraint means for restraining the vehicle.