JP3370236B2 - 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 work vehicle.

[0002]

2. Description of the Related Art There are some work vehicles in which a main transmission and an auxiliary transmission which are capable of shifting in a plurality of stages are arranged in series for traveling, and the main transmission and the auxiliary transmission are provided with a shift lever or the like. Each of them is configured to be independently shiftable.
Thus, for example, if the main transmission is configured to be able to shift to eight speeds and the auxiliary transmission is to be capable of shifting to two speeds, for example, the auxiliary transmission is shifted to a low speed position, and the main transmission is moved to
Even if the sub-transmission is operated from the low speed position to the high speed position in the state where the shift operation is performed to the high speed shift position, the main transmission is left at the fifth speed shift position. On the contrary, even if the auxiliary transmission is shifted from the high speed position to the low speed position,
It is left in the high gear position.

[0003]

In an agricultural tractor which is an example of the work vehicle as described above, for example, when plowing in a narrow field, the machine body is advanced from one end of the field to the other end. While doing the plow work, when reaching the other end of the field, the aircraft does not turn, but the aircraft continues to move backward and returns to one end of the field, and the plow work is performed while advancing the aircraft again. A work form in which various operations are repeated may be adopted.

In the case of such a work mode, during the plow work while moving forward, the auxiliary transmission is operated to the low speed position so that the main transmission is moved to the high speed shift position (for example, the 6th or 7th speed shift position). The shift operation is performed, and conversely, when the vehicle is moving backward, the auxiliary transmission is operated to the high speed position, and the main transmission is operated to the middle speed position (for example, the third speed position). In general, the low speed position of the auxiliary transmission is for traveling in the field, and the high speed position of the auxiliary transmission is for traveling. At the high speed position of the sub-transmission, the main transmission is shifted to a medium or low speed shift position when traveling on the field, and when traveling on the road, the main transmission is operated at the high speed position of the sub-transmission. In many cases, the shift operation is performed at a high speed shift position.

As a result, every time the auxiliary transmission is shifted to the low speed position and the high speed position during plow work while moving forward and during reverse travel, the main transmission is set to the high speed shift position and the medium speed (or low speed). Since it is necessary to shift to the shift position, there is room for improvement in terms of operability in shifting. An object of the present invention is to provide a traveling speed change structure for a work vehicle, which can cope with a work mode in which the shift position of the main transmission used is different at the low speed position and the high speed position of the auxiliary transmission.

[0006]

[I] A shift position of a main transmission is different between a low speed position and a high speed position of an auxiliary transmission, and the auxiliary transmission is repeatedly operated to shift to a low speed position and a high speed position. In the work mode, when the operator shifts the auxiliary transmission from the low speed position to the high speed position, the main transmission is shifted by the worker to a shift position suitable for the low speed position of the auxiliary transmission. When the operator shifts the sub transmission from the high speed position to the low speed position, the main transmission is shifted by the worker to a shift position suitable for the high speed state of the sub transmission.

According to the feature of claim 1, when the operator shifts the auxiliary transmission from the low speed position to the high speed position, the shift operation is performed corresponding to the low speed position of the auxiliary transmission during the shift operation.
Since the shift position of the main transmission that has been changed is stored and updated as the first shift position, when the worker again shifts the sub transmission from the high speed position to the low speed position, the main transmission shifts to the first shift position. Position (when the auxiliary transmission is
Accordingly , the gear shift operation is automatically performed to the gear shift position of the main transmission which has been shifted accordingly .

On the contrary, when the operator shifts the sub transmission from the high speed position to the low speed position, the sub shift during the shift operation is performed.
Since the shift position of the main transmission, which has been shifted corresponding to the high speed position of the speed device, is stored and updated as the second shift position, when an operator shifts the sub transmission from the low speed position to the high speed position again. , The main transmission is in the above-mentioned second shift position (the sub-transmission is shifted corresponding to the above-mentioned high speed position).
The shift position of the main transmission is automatically changed.

As described above, when the operator shifts the auxiliary transmission to the low speed position by the second manual operation tool, the main transmission is operated at the low speed position of the auxiliary transmission without operating the first manual operation tool. Therefore, when the worker shifts the auxiliary transmission to the high speed position by the second manipulating tool, the first manipulating tool is not operated. Also, the main transmission is automatically shifted to the second shift 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 make the first change according to the state of the field or the change of the working state.
When the main transmission is operated to change gears by the manual operation tool, when the auxiliary transmission is changed from the low speed position to the high speed position after that, the shift position of the main transmission after the speed change operation operated by the first manual operation tool. Is stored and updated as a new first shift position (a new shift position suitable for the low speed position of the auxiliary transmission in the main transmission). On the contrary, if the operator shifts the main transmission with the first manual operation tool in response to changes in the field condition or the working state at the high speed position of the auxiliary transmission, then the auxiliary transmission is changed from the high speed position to the low speed position. When shifting gears to the position, operate with the first artificial
The gear shift position of the main transmission after the gear shift operation is stored and updated as a new second gear shift position (a new gear shift position suitable for the state of the high speed position of the auxiliary gear shift device in the main gear shift device).

[II] According to the features of claim 2, as in the case of claim 1, the "action" described in the above [I] is provided, and in addition to this, the following "action" is provided. ing. Generally, the low speed position of the auxiliary transmission is for work traveling, and the high speed position of the auxiliary transmission is for traveling traveling. The main transmission is shifted to a medium or low speed shift position at the high speed position of the auxiliary transmission during traveling on the work site, and the main transmission is operated at the high speed position of the auxiliary transmission during traveling on the road. In many cases, the shift operation is performed at a high speed shift position.

As a result, for example, when the high speed shift position is stored as the second shift position (shift position suitable for the high speed position of the sub transmission in the main transmission), the worker shifts to the sub shift in the workplace. When the gear shift operation is performed from the low speed position to the high speed position, the main transmission automatically shifts to the high speed shift position (second shift position), and shock is generated during this shift operation, resulting in poor riding comfort. Will be things. According to the feature of claim 2, when the worker shifts the auxiliary transmission from the low speed position to the high speed position, the main transmission is prevented from being shifted to the high speed shift position. There is no shock at the time of gear shifting operation.

[0013]

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

The forward clutch 5 and the reverse clutch 6 are hydraulic multi-plate type in which a friction plate (not shown) and a piston (not shown) are combined, 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 directly flows from the forward clutch 5 to the cylindrical shaft 7, and the vehicle body moves forward. 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 the reverse rotation state via the reverse clutch 6 and the transmission shaft 20, and the machine 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 the 3rd and 4th speed clutches 24 are arranged in parallel and is capable of shifting to 4 speeds. By operating one of the 1st speed to 4th speed clutches 21 to 24 to the transmission side, The power from the cylindrical shaft 7 on the engine 1 side is subjected to a four-speed gear shift operation and transmitted to the lower transmission shaft 25.

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. By operating to the side, the power from the transmission shaft 25 on the first main transmission 10 side is
The gear is operated in two steps and is transmitted to the auxiliary transmission 12 on the lower side. The sub-transmission device 12 is of a synchromesh type in which the shift member 53 is slidably operated, and is capable of shifting in two stages, and is mechanically shifted by a shift lever 28 described later.

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

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

A pilot oil passage 50 is branched 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 the operation portions of the solenoid valves 31b, 32b, 33b, 34b, 36b, 37.
b, 42b, 44b, 47b, 48b are connected. Solenoid operated valves 31b to 34b, 36b, 37b, 42
b, 44b, 47b, and 48b are biased toward the oil discharge side (transmission cutoff side) by springs, and when these are electrically operated to the supply side, the pilot operating oil causes the switching valves 31a to 34a,
It is supplied to the operation parts of 36a, 37a, 42a, 44a, 47a, 48a, and these are operated to the supply side (transmission side).

(3) Next, the construction of the operating portions of the forward and reverse clutches 5, 6, the first and second main transmissions 10, 11 and the like will be described.
As shown in FIGS. 3 and 2, the forward and reverse clutches 5,
An on-off valve 51 capable of draining pilot hydraulic oil from the operation portions of the switching valves 36a and 37a of No. 6 is provided, and the on-off valve 51 is biased to the closed side by a spring, and the on-off valve 51 is mechanically opened to the open side. A clutch pedal 52 that is operated to is provided. At the base of the steering wheel 58 of the front wheel 19, a forward / backward lever 59 for transmitting an electric forward signal and a backward signal is provided.

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

A lock pin 56 that can be operated to move in and out is provided on a lateral side portion of the speed change lever 28, and an operation button 57 for operating the lock pin 56 to move in and out is provided in an upper portion of the speed change lever 28. The lock pin 56 is biased toward the projecting side by a spring (not shown) (the operation button 57 is also biased toward the projecting side on the left side of the drawing), and the lock pin 56 is engaged with the guide plate 60 on the fixed side. The gear shift lever 28 is held at each of the neutral position N, the low speed position L, and the high speed position H by combining them. 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 surface of the speed change lever 28. When the shift-up button 61 and the shift-down button 62 are pushed once, as will be described later, one shift operation is performed. 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 7-segment shift display portion 64 for displaying the shift positions (1st to 8th speeds) of the first and second main transmissions 10 and 11, and a forward / backward movement by a forward / reverse lever 59. A forward lamp 65 and a reverse lamp 6 which indicate which one of the clutches 5 and 6 is operated to the transmission side.
6. A neutral lamp 67 indicating that the speed change lever 28 is operated to the neutral position N is provided in the control section. Figure 3
As shown in FIG. 5, a pressure sensor 74 is provided to detect whether or not the operating pressures of the forward and reverse clutches 5 and 6 have reached a predetermined pressure in the transmission state, and the forward and reverse lamps 65 are detected by the pressure sensor 74. , 66 is turned on.

(4) Next, the shift 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 / backward 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 S1).
2) The switching valve 36a is operated to the supply side, the forward clutch 5 is operated to the transmission side, and the forward lamp 65 is turned on (step S3). Conversely, when the forward / reverse lever 59 is operated to the reverse position R (step S1), the operation current is supplied to the electromagnetic operation valve 37b shown in FIG. 3 (step S4), and the switching valve 37a is operated to the supply side. The reverse clutch 6 is operated to the transmission side, and the reverse lamp 66 lights up (step S
5), the buzzer 71 shown in FIG. 2 operates intermittently (step S6).

As shown in FIG. 1, the first main transmission 10 has four
Since the second main transmission device 11 can shift to two speeds, the first and second main transmission devices 10 and 11 can shift to eight speeds. In this case, the second main transmission 1
The first to fourth speed clutches 21 to 2 of the first main transmission 10 are in a state where the first low speed clutch 26 is operated to the transmission side.
4 corresponds to the shift positions of the 1st to 4th speeds, and the 1st to 4th speed clutches of the 1st main transmission device 10 in the state where the high speed clutch 27 of the 2nd main transmission device 11 is operated to the transmission side. 21 to 24 correspond to the shift positions of the fifth speed to the eighth speed.

As shown in FIG. 3, one of the first main transmissions 10
Each of the first to fourth speed clutches 21 to 24 and the low speed and high speed clutches 26 and 27 of the second main transmission device 11 is provided with a pressure sensor 74 for detecting whether or not the operating pressure has reached a predetermined pressure in a transmission state. Therefore, the current gear shift positions (1st to 8th gear) of the first and second main transmissions 10 and 11 are detected by the detection of the pressure sensor 74, and the detected gear shift positions are displayed on the gear shift display section 64. (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 once pushed (steps S8 and S9). In this case, as indicated by the solid line A1 (time point B1) in FIG. 5, when the shift-up button 61 is pressed, the first main transmission device 10 at the shift position one step higher than the current shift position.
When the operation current starts to be supplied to the electromagnetically operated valves 31b to 34b of No. 1 and the shift down button 62 is pressed to the contrary, the first main transmission device at the shift position one step lower than the current shift position. 10 solenoid operated valves 31b to 34b
The operation current is started to be supplied to (step S1
0).

At the same time, the solid line A2 in FIG. 5 (time point B1)
As shown in FIG. 5, the electromagnetic proportional valves 38, 39 of the low speed or high speed clutches 26, 27 operated on the transmission side in the second main transmission 11 cause the low speed or high speed clutches 26, 27 operated on the transmission side. 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, the operating pressure of the low speed clutch 26 of the second main transmission device 11 is reduced to zero during the shift operation from the 4th speed shift position to the 5th speed shift position, and the high speed clutch 2
The operating pressure of 7 is increased from zero to a predetermined low pressure P3. On the contrary, during the shift operation from the 5th speed shift position to the 4th speed shift 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 changed from zero to a predetermined low pressure. It is operated to ascend to P3.

Then, as indicated by the solid line A1 in FIG. 5 (from time B2 to time B3), 1 in the first main transmission 10 is selected.
1st to 4th speed clutches 21 to 2 on the higher speed side or the lower speed side
The operating pressure of No. 4 is increased to the operating pressure P1 in the transmission state by the electromagnetically operated valves 31b to 34b. At the same time, as indicated by the one-dot chain line A3 (time B2 to time B3) in FIG.
1 or 1st to 4th before the shift down button 62 is pressed
The operating pressure of the high speed clutches 21 to 24 is the solenoid operated valve 31b to
The operating pressure P1 in the transmission state is lowered to zero by 34b (step S12).

Next, the second pressure which was maintained at a 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 solenoid 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 clutch 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 rising characteristic of the operating pressure of the low speed or high speed clutch 26, 27 is set for each shift position,
The shift position on the lower speed side (first speed side) is 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 or the shift operation by pressing the shift down button 62 is completed. 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 pressed once. And the operator is informed of the end of the gear shift operation (step S15). The shift operation as described above is not continuously performed even if the shift-up button 61 or the shift-down button 62 is continuously pressed, and the shift-up button 61 or the shift-down button 62 is once returned and then pressed again. Otherwise, the next one shift operation will not be performed.

(5) Next, the shift operation of the auxiliary transmission 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 (the state in which the speed change lever 28 is held at the low speed position L by the operation button 57 and the lock pin 56), the operation button 5
When 7 is pushed and the lock pin 56 is retracted from the guide plate 60, the switching valve 36a is operated to the oil drain side by the electromagnetic operation valve 36b shown in FIG. 3, and the forward clutch 5 is automatically moved to the transmission cutoff side. To be operated.

As a result, the speed change 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 being pressed, and the operation button 57 is returned to operate the speed change lever 28 by the lock pin 56. The neutral position N or the high speed position H is maintained. In this case, when the operation button 57 is returned to the neutral position N, the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b, and the solenoid proportional valve 3 is operated.
5, the forward clutch 5 is immediately and automatically operated to the transmission side. When the operation button 57 is returned to 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 gradually and automatically moved to the transmission side by the electromagnetic proportional valve 35. To be operated.

When the forward / reverse lever 59 is operated to the reverse position R (the reverse clutch 6 is operated to the transmission side and the forward clutch 5 is operated to the transmission interruption side), the speed change 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 cutoff side and the transmission side, as described above.

(6) Next, when the speed change lever 28 is operated from the low speed position L to the high speed position H and when the speed change lever 28 is operated from the high speed position H to the low speed position L, the first and second main speed changes are performed. Device 1
A configuration in which 0 and 11 are automatically shifted to the first shift position Y1 and the second shift position Y2 will be described with reference to FIGS. 6 and 7. First, when the engine 1 is started,
The gear shift position of the eighth speed is set as the gear shift position Y1, and the gear shift position of the first speed is set as the second gear shift position Y2 (step S21).

As a result, the low speed position L of the speed change lever 28 is
When the speed change lever 28 is operated from the low speed position L to the high speed position H in the state where the first and second main transmissions 10 and 11 are operated to shift to the 8th speed shift position (steps S22 and S).
26), similarly to steps S10 to S15 of FIGS. 5 and 4, the first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first shift position). The second gear shift position Y2 (first gear shift position) is displayed on the gear shift display section 64 (steps S33 to S).
34).

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

On the contrary, 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),
Similar to steps S10 to S15 of FIGS. 5 and 4, the first and second main transmissions 10 and 11 are operated at the first shift position Y1.
(8th speed shift position) is automatically changed to the above-described first shift position Y1 (8th speed shift position) on the shift display portion 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),
Similar to steps S10 to S15 in FIGS. 5 and 4, the first and second main transmissions 10 and 11 are operated at the second shift position Y2.
The gear is automatically changed to (first gear shift position), and the second gear shift position Y2 (first gear shift position) is displayed on the gear shift display section 64.
Is displayed (steps S33 to S34).

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

(7) In the state of the above item (6), for example, when the shift lever 28 is operated to the low speed position L (step S22), the shift up button 61 and the shift down button 62 are pushed (step S23). , S24), and as in steps S10 to S15 of FIGS. 5 and 4 ((4) above).
(See step S25), first and second main transmissions 1
0 and 11 are shifted, and the first and second after the shifting operation
The shift positions of the main transmissions 10 and 11 are displayed on the shift display portion 64. After that, when the speed change lever 28 is operated from the low speed position L to the high speed position H (steps S22 and S26),
The gear shift positions of the first and second main transmissions 10 and 11 during this operation are stored and updated as the first gear shift position Y1 (step S32).

In this case, for example, if the shift position of the fifth speed of the first and second main transmissions 10 and 11 is stored and updated as the first shift position Y1, then the shift lever 28 first.
By operating the low speed position L to the high speed position H, the first operation is performed in the same manner as steps S10 to S15 of FIGS. 5 and 4.
And the second main transmissions 10 and 11 are connected to the second shift position Y2.
The gear is automatically changed to (first gear shift position), and the second gear shift position Y2 (first gear shift position) is displayed on the gear shift display section 64.
Is displayed (steps S33 to S34).

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

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

(8) In the state of the above item (6), for example, when the shift lever 28 is operated to the high speed position H (step S22), the shift up button 61 and the shift down button 62 are pushed (step S23). , S24), and as in steps S10 to S15 of FIGS. 5 and 4 ((4) above).
(See step S25), first and second main transmissions 1
0 and 11 are shifted, and the first and second after the shifting operation
The shift positions of the main transmissions 10 and 11 are displayed on the shift display portion 64.

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

In this case, for example, assuming that the shift position of the third speed 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
By operating the high speed position H to the low speed position L, the first operation is performed in the same manner as steps S10 to S15 in FIGS. 5 and 4.
And the second main transmissions 10 and 11 are connected to the first shift position Y1.
(8th speed shift position) is automatically changed to the above-described first shift position Y1 (8th speed shift position) on the shift display portion 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),
Similarly to steps S10 to S15 of FIGS. 5 and 4, the first and second main transmissions 10 and 11 are automatically shifted to the updated second shift position Y2 (third shift position). , The above-described updated second shift position Y on the shift display portion 64.
2 (shift position of the third speed) is displayed (step S33-).
Step S34).

As a result, when the shift position of the third speed 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 transmission devices 10, 11 are automatically shifted to the first shift position Y1 (shift position of the eighth speed), and the shift lever 28 is operated. By operating from the low speed position L to the high speed position H, the first and second
The state in which the main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (third shift position) is repeated.

As described above, at the low speed position L and the high speed position H of the speed change lever 28, the speed change operation of the first and second main transmissions 10 and 11 is performed to move the speed change lever 28 from the high speed position H to the low speed position L. When the low speed position L is operated to the high speed position H, the first gear shift position Y1 is repeatedly stored and updated from the eighth gear shift position to another gear shift position, and the second gear shift position Y2 is changed. It is repeatedly stored and updated from the first gear shift position to another gear shift position. When the engine 1 is stopped in the above-mentioned state (step S35) and the engine 1 is started again, the process returns to step S21, the eighth gear position is set as the first gear position Y1, and the first gear position is set as the second gear position Y2. The shift position of is set.

[Another Embodiment of the Invention] As described above, the state in which 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. On the other hand, 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 Y1 and Y2 are not updated, and the eighth shift position (first shift position Y1). Alternatively, the shift position of the first speed (the second shift position Y2) may be held so that the switching operation can be artificially performed.

The first and second main transmissions 10, 11 are
The present invention can also be applied to a work vehicle configured to be capable of shifting to six gears or six gears, and is also applicable to a work vehicle configured to be capable of shifting the auxiliary transmission 12 to three gears of a high speed position, a medium 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 hydraulic clutch types, but the first and second main transmissions 10 and 11 are replaced by the auxiliary transmission 1.
The gear shift type may be configured such that the shift member is slidably operated, and the shift member may be slid by a hydraulic cylinder to perform the gear shift operation.

[0054]

According to the first aspect of the present invention, in a traveling speed change structure for a work vehicle in which a main transmission and a sub transmission capable of shifting in a plurality of stages are arranged in series, a low speed position and a high speed position of the sub transmission are provided. In a work mode in which the gear position of the main transmission is different, when the second transmission is operated to shift the auxiliary transmission, the main transmission is 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 tool does not need to shift the main transmission device to the first and second shift positions described above. It was possible to improve the sex. In this case, the gear shift position of the main transmission when the auxiliary transmission is shifted to the low speed position and the high speed position is the first shift position without performing the special operation of 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 feature of claim 2, as in the case of claim 1, the "effect of the invention" of claim 1 is provided. According to the feature of claim 2, even if a high speed shift position is stored as the second shift position, for example, when the operator shifts the auxiliary transmission from the low speed position to the high speed position, the main transmission is set to the high speed side. Since the shift operation to the shift position is prevented from being restrained and no shock is generated during the shift operation, the ride comfort is improved.

[Brief description of drawings]

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

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

FIG. 3 is a hydraulic circuit diagram of 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 gear shift operation using a shift up button and a shift down button of a shift lever.

FIG. 6 is a diagram showing a flow of the first half when the auxiliary transmission is operated to shift from a high speed position to a low speed position and from a low speed position to a high speed position by a shift lever.

FIG. 7 is a diagram showing a second half flow when the auxiliary transmission is operated to shift from a high speed position to a low speed position and from a low speed position to a high speed position by a shift lever.

[Explanation of symbols]

10, 11 Main transmission 12 Auxiliary transmission 28 Second Artificial Manipulation Tool 61,62 1st manual operation tool L Low speed position of auxiliary transmission H High speed position of auxiliary transmission Y1 First shift position Y2 Second shift position

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

Claims (2)

(57) [Claims] 1. A main transmission device and a sub transmission device capable of shifting in a plurality of stages are arranged in series, and the operation of the first manual operation tool is supported based on a first artificial operation tool that is manually operated. And a second manual operation tool that is artificially operated by a speed change operation of the auxiliary transmission apparatus to shift the main transmission apparatus to a desired shift position. wherein each time the auxiliary speed change device is operated for speed change operation from the low speed position to the high speed position, us when this shift operation
The gear shifting operation is performed in correspondence with the low speed position of the auxiliary transmission.
And a first storage means for storing and updating the shift position of the main transmission as a first shift position, and a second storing operation for each time the auxiliary transmission is shifted from the high speed position to the low speed position by the second manipulating tool. you during shifting
The shift operation is performed in correspondence with the high speed position of the auxiliary transmission.
Second storage means for storing and updating the shift position of the main transmission as a second shift position, and the first manual operation tool for shifting the main transmission to a certain shift position. When the auxiliary transmission is operated to shift to the low speed position by the two-manual operation tool, the main transmission is automatically shifted prior to the shift control means so that the stored first shift position is reached. While the first transmission means to be operated and the first manual operation tool are operating to shift the main transmission device to a certain shift position, the second manual operation tool operates to shift the auxiliary transmission device to a high speed position. Then, a traveling shift of the work vehicle including a second shift device that automatically shifts the main transmission device prior to the shift control device so as to reach the stored second shift position. Construction. 2. When the sub-transmission is shifted from the low speed position to the high speed position by the second human-operated operation tool, the main transmission is shifted to the high speed position by the second shifting means. 2. The traveling speed change structure for a work vehicle according to claim 1, further comprising a restraint means for restraining restraint of the vehicle.