JP3266805B2 - Work vehicle traveling speed change structure - Google Patents

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] According to the features of claim 1, 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 to perform the shift operation In the case of (1), the operator manually shifts the sub-transmission to the neutral position with the second artificial operation tool and shifts the main transmission to the desired shift position (the low-speed position of the sub-transmission in the main transmission). When the sub-transmission is shifted to the low-speed position, the shift position of the main transmission at the time of this shift operation is set as the first transmission position. Conversely, after shifting to the desired shift position of the main transmission at the neutral position of the sub-transmission (shift position suitable for the state of the high-speed position of the sub-transmission in the main transmission), the sub-transmission is moved to the high-speed position. , The shift position of the main transmission at the time of the shift operation is set as the second shift position.

As described above, the first shift position (the shift position suitable for the low speed position of the subtransmission in the main transmission) and the second shift position (the high speed position of the subtransmission in the main transmission) When the operator shifts the sub-transmission to the low-speed position using the second artificial operation tool, the main transmission shifts to the first transmission position (the sub-transmission in the main transmission). The shift operation is automatically performed to the shift position suitable for the low-speed position of the device.
When the sub-transmission is shifted to the high-speed position by the second artificial operation tool, the main transmission is automatically shifted to the second transmission position (the transmission position suitable for the high-speed position of the sub-transmission in the main transmission). Operated.

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 shifted to 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 neutral 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 to the low speed position thereafter, the shift position of the main transmission after the shift operation is changed to a new first shift position (in the main transmission). It is set 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 the neutral position of the auxiliary transmission in accordance with a change in the state of the field or the work state, the speed of the auxiliary transmission is shifted to the high-speed position thereafter. When the gearshift operation is performed, the gearshift position of the main transmission after the gearshift operation is set and updated as a new second gearshift position (a new gearshift position suitable for the state of the high speed position of the subtransmission in the main transmission).

When the operator performs a shift operation of the main transmission at the neutral position of the auxiliary transmission, the first and the second shift positions (low-speed position and high-speed position) on the side where the auxiliary transmission is shifted from the neutral position. A second shift position is set. In this case, for example, when the sub-transmission is shifted to the low-speed position, the first transmission position at the low-speed position is set, so that the direction of the shift operation of the sub-transmission is set and the set first and second positions. Since the shift positions correspond to each other, there is no sense of incompatibility with the operation of setting the first and second shift positions by the operator.

[0011] In contrast to a normal shift state such as a shift operation of the main transmission at a low speed position and a high speed position of the auxiliary transmission, a main shift at a neutral position of the auxiliary transmission different from the normal shift state. Updating by setting the first and second shift positions can be performed by the shift operation of the device. Thereby, it is possible to easily determine whether the operator is in the normal shift state or the shift state for setting the first and second shift positions. There is no situation in which the first and second shift positions are incorrectly set even though there is no desire to set the position.

[II] According to the feature of the second aspect, similar to the case of the first aspect, it has the "action" described in the above-mentioned [I], and additionally has the following "action". ing. As described in the preceding paragraph [I], after the shift operation of the main transmission is performed at the neutral position of the sub-transmission, the operation of shifting the sub-transmission to the low-speed position and the high-speed position is repeated. The second shift position is set and updated many times.

According to a second aspect of the present invention, when the engine is started, for example, at the start of a day's work, the first and second shift positions are determined in advance. The position is replaced with the 2 shift position. Thus, if the operator knows the predetermined first and second shift positions in advance, the first
Also, there is no situation in which the operator does not understand which shift position the second shift position is set to start the operation by starting the engine.

[0014]

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 comprises 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 and 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 portion of the aircraft, and slides a shift member 53 of the auxiliary transmission 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 that the lock pin 56 can be moved 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. When the shift-up button 61 and the shift-down button 62 are pressed once as described later, one shift 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 and 11 is provided. 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 the above state, it is assumed that the shift-up button 61 or the shift-down button 62 of the shift lever 28 is pressed once (steps S8, 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 a 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 operation 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 downshift 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 shifting 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 in a state where 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 in which the forward / reverse lever 59 is operated to the reverse position R (a state in which the reverse clutch 6 is operated on the transmission side and the forward clutch 5 is operated on the transmission cutoff side), the shift lever 28 is operated as described above. 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 shift lever 28 is moved to the high-speed position H.
To the low-speed position L (steps S22 and S2).
3, S32, S33), step S10 in FIG. 5 and FIG.
To the first and second main transmissions 10, 1 in the same manner as in S15 to S15.
1 is automatically shifted to the first shift position Y1 (8th shift position), and the above-described first shift position Y1 (8th shift position) is displayed on the shift display section 64 (step S37).
-Step S38).

Conversely, when the shift lever 28 is operated from the low speed position L to the high speed position H (steps S22, S23, S3).
2, S35), Steps S10 to S15 in FIGS. 5 and 4
The first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first-speed shift position) in the same manner as described above, and the second shift position Y2 is displayed on the shift display section 64. (1
Is displayed (steps S39 to S40).

As described above, in the initial state where the engine 1 is started, when 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 operated.
Is automatically shifted to the first shift position Y1 (8th shift position), and when 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, 11 are shifted.
Is automatically shifted to the second shift position Y2 (first speed shift position).

(7) When the shift lever 28 is operated to the neutral position N after the state of (6), the power is cut off in the sub-transmission 12 and the machine stops. When the shift lever 28 is operated to the neutral position N (step S23), the shift-up button 61 and the shift-down button 62 are pressed (steps S24, S2).
5) The first and second main transmissions 1 according to the pushing operation.
The gears 0 and 11 are shifted to the one-step high-speed side or the one-step low-speed side (steps S26, S27, S28 and S29), and the shift position of the first and first main transmissions 10 and 11 is changed every time the shift operation is performed. It is displayed on the display unit 64 (step S30), and the buzzer 71 operates only once (step S31). In this case, since the airframe is stopped, the operation of lowering the operating pressure of the low-speed and high-speed clutches 26 and 27 to the predetermined low pressure P3 as in the previous section (4) and steps S11 and S13 in FIGS. The raising operation to the operating pressure P2 in the transmission state is not performed.

As described above, in the neutral position N of the shift lever 28, the first and second main transmissions 10, 1 are operated by the shift-up button 61 and the shift-down button 62.
1 is operated, the shift lever 28 is operated from the neutral position N to the low speed position L (steps S23, S32, S32).
33), the first and second main transmissions 10, 1 at the time of this operation.
The first shift position is set and updated as the first shift position Y1 (step S34).

In this case, if, for example, the fifth shift position of the first and second main transmissions 10 and 11 is set and updated as the first shift position Y1, the shift lever 28
Has been operated to the low speed position L, the first and second main transmissions 10 and 11 are operated in the same manner as steps S10 to S15 in FIGS.
The shift operation is automatically performed to (the fifth-gear shift position), and the first shift position Y1 (the fifth-gear shift position) is displayed on the shift display section 64.
Is displayed (steps S37 to S38).

Next, when the shift lever 28 is operated from the low speed position L to the high speed position H (steps S22, S23, S3).
2, S35), Steps S10 to S15 in FIGS. 5 and 4
The first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first speed shift position) in the same manner as described above, and the second shift position Y2 (1 Is displayed (steps S39 to S4).
0).

As a result, when the fifth shift position is set 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) above, after the first and second main transmissions 10 and 11 are shifted by the shift up button 61 and the shift down button 62 at the neutral position N of the shift lever 28, When the shift lever 28 is operated from the neutral position N to the high-speed position H (steps S23 and S23).
32, S35), the shift position of the first and second main transmissions 10, 11 at the time of this operation is set and updated as the second shift position Y2 (step S36).

In this case, for example, if the third shift position of the first and second main transmissions 10 and 11 is set and updated as the second shift position Y2, first the shift lever 28
Has been operated from the neutral position N to the high-speed position H, the first position has been changed in the same manner as in steps S10 to S15 in FIGS.
And the second main transmissions 10 and 11 are automatically shifted to the updated second shift position Y2 (third shift position), and the shift display portion 64 displays the second shift position Y2 ( 3
Is displayed (steps S39 to S40).

Next, when the shift lever 28 is operated from the high speed position H to the low speed position L (steps S22, S23, S3).
2, S33), Steps S10 to S15 in FIGS. 5 and 4
The first and second main transmissions 10 and 11 are automatically shifted to the first shift position Y1 (8th shift position) in the same manner as described above, and the first shift position Y1 (8 Is displayed (steps S37 to S3).
8).

When the third shift position is set 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 neutral position N of the shift lever 28, and the shift lever 28 is operated to the low speed position L and the high speed position H. The first shift position Y1 is repeatedly set and updated from the eighth shift position to another shift position, and the second shift position Y2 is shifted from the first shift position to another shift position. The degree is also set and updated.

In this case, even if the shift lever 28 is operated to the neutral position N, the shift-up button 61 and the shift-down button 62 are never pressed and operated (the shift of the first and second main transmissions 10 and 11 is not performed). Without performing any operation) (Step S
23, S24, S25), and shift lever 28 to neutral position N
, The update by setting the first and second shift positions Y1 and Y2 is not performed (steps S23, S32, S33 and S35). In the above state, the engine 1 is stopped (step S4
1) 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.

[Another Embodiment of the Invention] As described above, the shift lever 28 is shifted from the neutral position N to the low speed position L and the high speed position H.
When the first and second shift positions Y1 and Y2 are set and updated each time the operation is performed, the shift operation of the first and second main transmissions 10 and 11 is performed at the neutral position N of the shift lever 28. Is performed, the shift lever 28 is operated from the neutral position N to the low-speed position L and the high-speed position H, regardless of this.
In a state where the 8th-speed shift position (first shift position Y1) and the 1st-speed shift position (second shift position Y2) are maintained without being updated by the setting of the second shift positions Y1 and Y2, It may be configured such that the switching operation can be performed in a targeted manner.

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 device is different, when the second artificial operation device shifts the speed of the auxiliary transmission device, the main transmission device is shifted to the first and second positions suitable for the low speed position and the high speed position of the auxiliary transmission device. 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 first and second shift positions can be updated by setting the first and second shift positions by performing a shift operation of the main transmission at a neutral position of the sub-transmission that is different from the normal shift state. Since the state where the second shift position is incorrectly set does not occur, there is no sense of incongruity at the time of the shift operation of the auxiliary transmission device due to the incorrect setting of the first and second shift positions. Since the direction of the shift operation of the auxiliary transmission corresponds to the set first and second shift positions,
The operator does not feel uncomfortable with the operation of setting the first and second shift positions, and the operability is good.

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 second aspect of the present invention, when the engine is started, the first and second shift positions are replaced with predetermined first and second shift positions. This prevents a situation in which the operator performs an erroneous operation in a state where the operator does not understand which shift position is set.

[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]

 Reference Signs List 1 engine 10, 11 main transmission 12 auxiliary transmission 28 second artificial operation device 61, 62 first artificial operation device L low speed position of auxiliary transmission device H high speed position of auxiliary transmission device N neutral position of auxiliary transmission device Y1 first Shift position Y2 Second shift position

Continuation of the front page (56) References JP-A-7-137553 (JP, A) JP-A-7-139618 (JP, A) JP-A-2-256957 (JP, A) JP-A-6-50420 (JP) JP-A-6-320974 (JP, A) JP-A-5-164222 (JP, A) JP-A-3-50032 (JP, A) JP-A-4-335816 (JP, A) 6-87347 (JP, A) Japanese Utility Model Showa 61-139350 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 20/02-20/08 F16H 59/00-63 / 48 G05G 1/00-25/04 F16H 3/02

Claims (2)

(57) [Claims] 1. A first artificial operation device comprising: a main transmission device capable of shifting to a plurality of speeds; and an auxiliary transmission device having a neutral position, which are arranged in series, and the first artificial operation device is manually operated. Gear shifting control means for shifting the speed of the main transmission to a shift position corresponding to the operation of the gear; and a second artificial operation tool for shifting the speed of the sub-transmission and being artificially operated. In a state where the transmission is shifted to the neutral position, the main transmission is shifted by the first artificial operation tool, and thereafter the sub-transmission is shifted from the neutral position to the low-speed position by the second artificial operation tool. When a shift operation is performed, a first setting unit that sets and updates the shift position of the main transmission at the time of the shift operation as a first shift position; and, in a state where the sub-transmission is shifted to a neutral position, The first artificial operation tool When the main transmission is shifted, the sub-transmission is shifted from the neutral position to the high-speed position by the second artificial operation tool, and then the main transmission is shifted. A second setting means for setting and updating as a second shift position; and a sub-transmission by the second artificial operation tool while the main transmission is being shifted to a certain shift position by the first artificial operation tool. A first shift means for automatically shifting the main transmission to the set first shift position prior to the shift control means when a shift operation is performed to a low speed position; When the sub-transmission is shifted to a high-speed position by the second artificial operation tool while the main transmission is being shifted to a certain shift position by the transmission, the main transmission is prioritized to the shift control means. Gearbox in front Automatically shift operation to the second speed change means and the travel gear structure of the working vehicle that is equipped with the second shift position being set. 2. A storage device for storing a predetermined first shift position and a predetermined second shift position determined in advance, wherein the first and second setting units are set when the engine is started. 2. The traveling speed change structure for a work vehicle according to claim 1, further comprising a replacement means for replacing the first and second speed change positions with the predetermined first and second speed change positions.