JP3274354B2 - 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 that can be shifted to a plurality of speeds for traveling and an auxiliary transmission that can be shifted to a high and low speed in two stages. In this case, the main transmission and the auxiliary transmission are configured to be independently shiftable by a shift lever or the like.

[0003]

When the above-mentioned main transmission and auxiliary transmission are provided, for example, the main transmission can be shifted up to 8 speeds and the auxiliary transmission can be shifted up and down to 2 speeds. Assuming that the main transmission was in the low-speed position of the sub-transmission, the traveling system was in the 1st to 8th speed,
At the high speed position of the sub-transmission, the gear can be shifted to a total of 16 gears, ie, the first to eighth speed shift positions of the main transmission.

[0004] For example, suppose that the sub-transmission is shifted from a low-speed position to a high-speed position while the sub-transmission is shifted to a low-speed position and the main transmission is shifted to a fifth-speed shift position. In this case, the main transmission is left at the fifth speed shift position regardless of the shift operation of the subtransmission, so that the fifth speed shift position at the low speed position (the fifth speed position as the travel system) is used as the traveling system. ), The shift operation is performed to the fifth shift position at the high-speed position (13th shift position as the traveling system) (for example, the traveling speed at the fifth shift position is 0.59 km / km).
h, the traveling speed at the 13th position is 5.80 km / h
Becomes).

Conversely, if the sub-transmission is shifted to the high speed position and the main transmission is shifted to the fifth speed, for example, if the sub-transmission is shifted from the high position to the low position, Since the main transmission remains at the fifth gear position irrespective of the speed change operation of the auxiliary transmission, the traveling system has a fifth gear position at the high speed position (1st gear as the traveling system).
The shift operation is performed from the third speed position to the fifth speed shift position at the low speed position (the fifth speed position as the traveling system).

[0006] As described above, when the speed change operation of the auxiliary transmission is performed, the shift position of the traveling system may change significantly, so that the traveling speed of the body also greatly changes and a shock may occur. Yes, there is room for improvement in terms of riding comfort. The present invention relates to a traveling speed change structure of a work vehicle in which a main transmission that can be shifted to a plurality of speeds for traveling and an auxiliary transmission that can be shifted to a high and low speed are arranged in series. It aims to improve comfort.

[0007]

[Means for Solving the Problems]

[I] For example, it is assumed that the main transmission is configured to be capable of shifting to eight speeds, the subtransmission is configured to be capable of shifting to two highs and lows, and is configured to be capable of shifting to 16 speeds as a traveling system. In this case, according to the first aspect of the present invention, for example, a state in which the first artificial operation device shifts the speed of the main transmission to the fifth gear position and the second artificial operation device shifts the speed of the auxiliary transmission to the high-speed position. (13th gear position as the traveling system), when the sub-transmission is shifted from the high-speed position to the low-speed position by the second artificial operation tool, the main transmission is shifted to the first speed higher than the fifth-speed shift position. The shift operation is automatically performed to the position (for example, if the main transmission is automatically shifted to the eighth shift position (first shift position), the shift position is set to the eighth speed position as the traveling system). Thus, the shift position as the traveling system before the gearshift operation of the auxiliary transmission (the 13th speed position described above) and the gearshift position as the traveling system after the gearshift operation of the auxiliary transmission (the 8th gear as described above) are performed.
(Speed position) is smaller than in the prior art configuration, and the accompanying change in the running speed of the aircraft is also small.

Conversely, for example, in a state where the main transmission is shifted to the fifth shift position by the first artificial operation tool and the subtransmission is shifted to the low speed position by the second artificial operation tool (as a traveling system). (5th-speed position), when the sub-transmission is shifted from the low-speed position to the high-speed position by the second artificial operation tool, the main transmission is automatically shifted to the second transmission position lower than the 5-speed transmission position. Is operated (for example, if the main transmission is shifted to a first-gear shift position (second shift position),
It becomes the 9th speed position as a traveling system). Thus, the shift position as the traveling system before the shift operation of the auxiliary transmission (the above-described 5 position).
Speed difference) and the shift position (the above-described ninth speed position) as a traveling system after the shift operation of the auxiliary transmission device is smaller than in the configuration of the related art. The change is small.

[II] Generally, in a working vehicle such as an agricultural tractor, the speed of the main transmission is operated while the sub-transmission is held at the low speed position in the field, and the sub-transmission is held at the high speed position on the road. Shift the main transmission. In such a work vehicle, work in the field (low-speed position of the auxiliary transmission) and movement on the road (high-speed position of the auxiliary transmission)
In a work mode in which the main transmission is shifted to the same shift position at both the low speed position and the high speed position of the auxiliary transmission, it is preferable in terms of operability and workability. is there.

According to the first aspect of the present invention, the main transmission is automatically shifted to a shift position different from the first and second shift positions when the sub-transmission is shifted. be able to. In this case, when the forward / reverse switching device different from the main and auxiliary transmissions is switched to the neutral position and the aircraft is stopped, the first artificial operation device causes the main transmission to move from the fifth gear position, for example. When the shift operation is performed to the third shift position, the third shift position is stored. Thereafter, when the sub-transmission is shifted from the low-speed position to the high-speed position as described above (by shifting from the high-speed position to the low-speed position) by the second artificial operation tool, the main transmission is moved to the first and second positions. The shift operation is automatically performed not at the shift position but at the stored third shift position.

[III] The operation of storing the shift position of the main transmission as described in the above item [II] can be performed without error when the body is stopped. In this case, it is conceivable that the auxiliary transmission is shifted to the neutral position by the second artificial operation tool to stop the body, and the storage operation of the shift position of the main transmission as described above is performed. Since the second artificial operation tool is frequently operated at the time of a normal shift operation for traveling, the operator does not recognize that the operation of storing the shift position of the main transmission as described above is performed. If the first manual operation device is operated when the sub-transmission is shifted to the neutral position by the two-manual operation device, the above-described operation of storing the shift position of the main transmission device may be erroneously performed. There is.

According to a first aspect of the present invention, there is provided a forward / reverse switching device that is not operated during a normal speed change operation for traveling.
The storage operation of the shift position of the main transmission as described above is performed in a stopped state of the aircraft in which the forward / reverse switching device is switched to the neutral position. With this, the operator switches the forward / reverse switching device to the neutral position with the recognition that the operation of storing the shift position of the main transmission as described above is performed, and the shift position of the main transmission as described above. Will be performed.

[IV] According to the feature of the second aspect, similar to the case of the first aspect, the "action" described in the above-mentioned [I], [II] and [III] is provided. It has various “actions”. According to a second aspect of the present invention, when the engine is operated to stop while the shift position of the main transmission that has been shifted at the neutral position of the forward / reverse switching device is stored, the stored shift position is erased. Is done. Therefore, when the engine is operated to start and the sub-transmission is shifted, the main transmission is automatically shifted to the first and second shift positions as described in [I] above.

The state in which the engine is stopped as described above means that the work of one day is completed, or that the work equipment is changed to enter a work form different from the previous work form. Because it is a state at the time of such a large switch,
If the main transmission is configured to automatically return to the basic state in which the main transmission is automatically shifted to the first and second shift positions at such a large changeover, the state of the work vehicle can be changed to any state. It is possible to avoid a situation in which the worker is confused because he or she cannot grasp whether there is any.

[0015]

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 transmitted to the left and right rear wheels via the forward clutch 5 or the reverse clutch 6, the cylindrical shaft 7, the first main transmission 10, the second main transmission 11, the auxiliary transmission 12, and the rear wheel differential 13. 1
4 is transmitted. The power branched immediately before the rear wheel differential device 13 is transmitted to the transmission shaft 15 and the hydraulic clutch type front wheel transmission 1.
6. 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 2
The transmission is shifted to the next stage 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. Each switching valve 31a-34
a, 36a, 37a, 42a, 44a, 47a, 48a
Is urged toward the oil drain side (transmission blocking side) by a spring, and is operated on the supply side (transmission side) by supplying 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 valves 31a to 34a, 36a, 37a, 42a, 44a,
47a, 48a are connected to the operation units, and each operation unit is provided with an electromagnetic operation valve 31b, 32b, 33b, 34b, 36b,
37b, 42b, 44b, 47b, 48b are connected. Each of the solenoid operated valves 31b to 34b, 36b, 37b,
The springs 42b, 44b, 47b, and 48b are urged toward the oil discharge side (the transmission cutoff side) by springs. When these are electrically operated to the supply side, the pilot hydraulic oil is switched to the switching valves 31a to 34.
a, 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 on-off 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 on-off valve 51 is closed by a spring. A clutch pedal 52 that is biased and mechanically operates 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 that can be operated at three positions, ie, a neutral position N, a forward position F, and a reverse position R, and that transmits an electrical neutral signal, a 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 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 63 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. 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 the 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, a 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. As shown in FIG. 1, the first main transmission 10 can shift to four speeds and the second main transmission 11 can shift to two speeds. Is possible. In this case, while the low speed clutch 26 of the second main transmission 11 is being operated on the transmission side, the first to fourth speed clutches 21 to 24 of the first main transmission 10 are shifted to the first to fourth speed shift positions. The high-speed clutch 2 of the second main transmission 11
7 is being operated on the transmission side, the first main transmission 1
The first to fourth speed clutches 21 to 24 correspond to the fifth to eighth speed 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 each pressure sensor 74, and the detected shift positions are displayed on the shift display unit 64. It is displayed (step S9).

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 S10, S11). 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 is shifted to a shift position one step higher than the current shift position. 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. Solenoid operated valve 31 for 10
The operation current starts to be supplied to b to 34b (step S12).

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 transmitting operating pressure P2 to a predetermined low pressure P3 (step S13). 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 the time point B2 to the time point B3), the first to fourth speeds before the shift-up button 61 or the shift-down button 62 of the first main transmission 10 are pressed.
The operating pressure of the fourth speed clutches 21 to 24 is reduced by the solenoid operated valve 31b.
In step S14, the operating pressure P1 in the transmission state is lowered to zero by means of .about.34b.

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).
5). 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 S16), and the buzzer 71 is operated once. And the operator is notified of the end of the shift operation (step S17). 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 forward / reverse switching operation by the forward / reverse lever 59 and the auxiliary transmission 12 by the shift lever 28
The shift operation will now be described. As shown in FIG.
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. The forward clutch 5 is operated to the transmission side,
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), an operation current is supplied to the electromagnetically operated 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, the reverse lamp 66 lights up (step S5), and the buzzer 71 operates intermittently (step S6).

When the forward / reverse lever 59 is operated to the neutral position N (step S1), the forward and reverse clutches 5,
6, the operation currents of both the solenoid operated valves 36b and 37b are cut off (step S7), and the forward and reverse clutches 5 and 6 are turned off.
Are operated to the transmission interruption side, and the neutral lamp 67 is turned on (step S8). When the clutch pedal 52 shown in FIG. 3 is depressed, regardless of the operation position of the forward / reverse lever 59, the opening / closing valve 51 is opened, and the operation current of both the electromagnetic operation valves 36b and 37b is cut off. , And both the forward and reverse clutches 5, 6 are operated to the transmission interruption side.

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 cutoff side), and the shift lever 28 is operated to the low speed position L. In this state (when the shift lever 28 is held at the low-speed position L by the operation button 57 and the lock pin 56), when the operation button 57 is pressed and the lock pin 56 is retracted from the guide plate 60, The switching valve 36a is operated by the solenoid operated valve 36b shown in FIG.
Is operated to the oil discharge side, and the forward clutch 5 is automatically operated to the transmission cutoff side.

With this operation, 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. Neutral stop position N
Alternatively, it is held at the high-speed position H. In this case, when the operation button 57 is returned in the neutral position N, the solenoid operated valve 36
The switching valve 36a is operated to the supply side by b, and the forward clutch 5 is automatically operated to the transmission side immediately by the electromagnetic proportional valve 35. When the operation button 57 is returned in the high-speed position H, the switching valve 36a is operated to the supply side by the electromagnetic operation valve 36b, and the forward clutch 5 is automatically operated to the transmission side gradually by the electromagnetic proportional valve 35.

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 interruption side and the transmission side.

(6) When the shift lever 28 is operated from the high-speed position H to the low-speed position L 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 are operated. 10 and 11 are the first stored in advance.
A configuration in which the gears are automatically shifted to the second shift positions Y1 and Y2 will be described with reference to FIGS. When the engine 1 is stopped (step S21), such as when a day's work is completed, the first shift position Y1 is set to the eighth shift position, and the second shift position Y2 is set to the first shift position. Is set (step S22).

Next, the start operation of the engine 1 is performed (step S23), and when the upshift button 61 and the downshift button 62 are pressed (steps S26, S26).
27), as in steps S12 to S17 in FIGS. 5 and 4 (see (4) in the preceding paragraph) (step S28), the first and second main transmissions 10 and 11 are shifted to desired shift positions. .

When the shift lever 28 is operated to the high speed position H,
When the shift lever 28 is operated from the high-speed position H to the low-speed position L while the first and second main transmissions 10 and 11 are performing a shift operation to a certain shift position (step S2).
5, S29), steps S12 to S17 in FIG. 5 and FIG.
Similarly, the first and second main transmissions 10 and 11 are automatically shifted to the first shift position Y1 (8th shift position), and the 8th shift position is displayed on the shift display section 64. (Steps S30 to S31). Thereafter, when the shift-up button 61 and the shift-down button 62 are pressed (steps S26 and S27), FIGS.
(Step S28) as in steps S12 to S17 (step S28).
The gears 0 and 11 are shifted from the eighth gear position to another desired gear position.

In the above-described state, when the shift lever 28 is operated from the high-speed position H to the neutral position N, and then is not operated to the low-speed position L but is again operated to the high-speed position H,
The first and second main transmissions 10 and 11 are connected to a first transmission position Y1.
(The 8th speed shift position) and the gear is left at the original speed change position without being operated. Thereafter, when the shift-up button 61 and the shift-down button 62 are pressed (Step S)
26, S27), and steps S12 to S1 in FIGS.
7 (see (4) above) (step S2
8) The first and second main transmissions 10, 11 are shifted to another desired shift position.

The above state will be described more specifically.
A state in which the first and second main transmissions 10 and 11 are operated to shift to the fifth shift position, the shift lever 28 is operated to the high speed position H, and the shift display section 64 displays the fifth shift position. 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, 11
Is shifted from the fifth gear position to the eighth gear position (the first transmission Y
The shift operation is automatically performed in 1), and the shift position of the eighth speed is displayed on the shift display section 64. In the state described above, after the shift lever 28 is operated from the high speed position H to the neutral position N,
When the vehicle is again operated to the high-speed position H without being operated to the low-speed position L, the first and second main transmissions 10 and 11 are not operated to shift to the eight-speed gear position (the first gear position Y1). The gear shift display section 64 also displays the gear position of the fifth speed, being left at the gear position of the fifth speed, which is the original gear position.

The shift lever 28 is operated to the low speed position L,
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 performing a shift operation to a certain shift position (Step S2).
5, S29), steps S12 to S17 in FIG. 5 and FIG.
Similarly, the first and second main transmissions 10 and 11 are automatically shifted to the second shift position Y2 (first shift position), and the shift display portion 64 displays the first shift position. (Steps S32 to S33). Thereafter, when the shift-up button 61 and the shift-down button 62 are pressed (steps S26 and S27), FIGS.
(Step S28) as in steps S12 to S17 (step S28).
The gears 0 and 11 are shifted from the first gear position to another desired gear position.

In the above-described state, if the shift lever 28 is operated from the low-speed position L to the neutral position N and then to the high-speed position H but is operated to the low-speed position L again,
The first and second main transmissions 10 and 11 are in a second transmission position Y2.
The gear is not shifted to (first gear position) but remains at the original gear position. Thereafter, when the shift-up button 61 and the shift-down button 62 are pressed (Step S)
26, S27), and steps S12 to S1 in FIGS.
7 (see (4) above) (step S2
8) The first and second main transmissions 10, 11 are shifted to another desired shift position.

The above state will be described more specifically.
A state in which the first and second main transmissions 10 and 11 are shifted to the fifth speed shift position, the shift lever 28 is operated to the low speed position L, and the shift display unit 64 displays the fifth speed shift position. 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
Is changed from the fifth gear position to the first gear position (second gear position Y
The shift operation is automatically performed in 2), and the first shift position is displayed on the shift display section 64. In the state described above, after the shift lever 28 is operated from the low speed position L to the neutral position N,
If the first and second main transmissions 10 and 11 are not operated to the high-speed position H but are operated to the low-speed position L again, the first and second main transmissions 10 and 11 are not operated to shift to the first-speed shift position (second shift position Y2). The gear shift display section 64 also displays the gear position of the fifth speed, being left at the gear position of the fifth speed, which is the original gear position.

(7) By step S22 shown in FIG.
In a state where the 8th speed shift position is set as the first shift position Y1 and the 1st speed shift position is set as the second shift position Y2, the forward / reverse lever 59 shown in FIG. Assume that the aircraft has stopped (step S2
4). In this state, when the shift-up button 61 and the shift-down button 62 are pressed (step S
34, S35), the first and second main transmissions 10, 11 are shifted to the first-stage high-speed side or the first-stage low-speed side in response to the pushing operation (steps S36, S37). The shift positions of the first and second main transmissions 10, 11 are displayed on the shift display section 64 (step S38), the buzzer 71 operates only once (step S39), and the first and second main shifts at this time. The shift positions of the devices 10 and 11 (for example, the third shift position and the fourth shift position) are set as the first shift position Y1 and the second shift position Y2 (step S40).

Thus, in a state where the forward / reverse lever 59 is operated to the neutral position N and the machine is stopped, the shift-up button 61 and the shift-down button 62 are pressed several times, and the first and second main shifts are performed. When the forward / reverse lever 59 is operated from the neutral position N to the forward position F or the reverse position R after the gearshift operation of the devices 10, 11 to the desired shift position, the first forward / backward lever 59 is operated immediately before the forward / backward lever 59 is operated. And the second
The shift positions of the main transmissions 10 and 11 (the desired shift positions described above) remain as the first shift position Y1 and the second shift position Y2.

Accordingly, when the shift lever 28 is subsequently operated from the high-speed position H to the low-speed position L (step S25,
S29), the first and second main transmissions 10 and 11 are in the above-described shift position (the shift positions of the first and second main transmissions 10 and 11 immediately before the forward / reverse lever 59 is operated) (first shift position) In Y1), the speed change operation is automatically performed. Conversely, also when the shift lever 28 is operated from the low-speed position L to the high-speed position H (steps S25 and S29), the first and second shift operations are similarly performed.
When the main transmissions 10 and 11 are in the aforementioned shift positions (the first and second main transmissions 10 and 10 just before the forward / reverse lever 59 is operated).
The shift operation is automatically performed to the eleventh shift position) (second shift position Y2). When the engine 1 is stopped in the above state (step S21), the eighth shift position is set again as the first shift position Y1, and 1 is set as the second shift position Y2.
The speed change position is set (step S22).

[Another Embodiment of the Invention] In step S22 shown in FIG. 6, the first shift position Y1 is set to the seventh speed or the sixth speed.
The second shift position Y2 may be configured to set a second shift position or a third shift position. Steps S24 to S40 in FIG.
In the same manner, in the state where the clutch pedal 52 shown in FIG. 3 is depressed and both the forward and reverse clutches 5 and 6 are operated to the transmission cutoff side, the steps S34 to S34 are similarly performed.
The first and second shift positions Y1 and Y2 in S40 may be set.

As described above, the first and second shift positions Y
1 and Y2, when the speed change lever 28 shifts the speed of the auxiliary transmission 12 to the low speed position L and the high speed position H, the first and second shift positions Y1 and Y2 move to the first and second shift positions Y1 and Y2. The first and second shift positions Y1 and Y2 are in the state in which the second main transmissions 10 and 11 are automatically shifted (the state of the above-described [embodiment of the present invention]), and the first and second shift positions Y1 and Y2. When the second main transmissions 10 and 11 are not shifted, the first
The second main transmissions 10 and 11 may be configured to be able to be artificially switched between two states in which the second main transmissions 10 and 11 are left at the same shift position.

In the configuration shown in FIGS. 1 to 7, the auxiliary transmission 1
2 is a low-speed position L and the first and second main transmissions 10 and 11 are in a high-speed position H and the first and second main transmissions 10 and 11 are in a first-speed gear position. The speed change position is set to be higher speed, and the speed change range at the low speed position L (speed change position of 1st to 8th speed) and the speed change range at high speed position H (speed change position of 1st to 8th speed) Although they are separated so that they do not overlap at all, the vicinity of the 6th to 8th gear shift position at the low speed position L and the vicinity of the 1st to 3rd gear shift position at the high speed position H are set so as to overlap. The present invention can also be applied to a working vehicle. The first and second main transmissions 10 and 11 have 10-speed or 6-speed.
The present invention is also applicable to a work vehicle configured to be able to shift to a gear.

In the configuration shown in FIG. 1, the first and second main transmissions 10 and 11 are of 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. Although the forward and reverse clutches 5 and 6 are provided in the configuration shown in FIG. 1, a forward / reverse switching device that is switched by sliding the shift member, such as the auxiliary transmission 12 shown in FIG. And may be provided in place of the reverse clutches 5, 6.

[0054]

According to the first aspect of the present invention, there is provided a traveling speed change structure for a working vehicle in which a main transmission which can be shifted to a plurality of speeds and an auxiliary transmission which can be shifted to a high and low speed are arranged in series. By automatically shifting the main transmission so that the shift position of the traveling system does not significantly change with the shift operation of the vehicle, the change in the traveling speed of the aircraft before and after the shift operation of the auxiliary transmission and the shock can be suppressed. And improved the riding comfort of the work vehicle. Depending on the work mode, at both the low speed position and the high speed position of the subtransmission,
When the main transmission is shifted to the same shift position,
Even in a state favorable in terms of operability and workability, the main transmission is automatically shifted to a shift position different from the first and second shift positions when the auxiliary transmission is shifted. Since it can be made to be able to do so, versatility and workability are high. The storage operation of the shift position at which the main transmission is automatically shifted when the subtransmission is shifted is performed,
As described above, the operation can be performed in a state in which the worker recognizes that the operation of storing the shift position of the main transmission device as described above is referred to as the neutral position of the forward / reverse switching device. The storage operation of the shift position of the main transmission is reliably performed without error.

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, the main transmission automatically returns to the basic state in which the main transmission is automatically shifted to the first and second shift positions at the time of a large changeover operation called an engine stop operation. It is possible to prevent a situation in which the user is confused and performs an erroneous operation.

[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 switching operation to a forward position, a reverse position, and a neutral position by a forward / reverse lever, and 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 illustrating a first half of a 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 illustrating the latter half of the flow when the shift lever is operated to shift the subtransmission from the high speed position to the low speed position and from the low speed position to the high speed position.

[Explanation of symbols]

 Reference Signs List 1 engine 5, 6 forward / reverse switching device 10, 11 main transmission device 12 auxiliary 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 N forward / reverse Neutral position of switching device Y1 First shift position Y2 Second shift position

Continuation of front page (56) References JP-A-6-50420 (JP, A) JP-A-2-256957 (JP, A) JP-A-7-137553 (JP, A) JP-A-7-139618 (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) Fully open 1986-139350 (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 forward / reverse switching device having a neutral position, a main transmission device capable of shifting to a plurality of speeds, and an auxiliary transmission device capable of shifting to a high / low speed stage are arranged in series, and are artificially operated. A shift control means for shifting the main transmission to a shift position corresponding to the operation of the first artificial operation tool based on the one-man-made operation tool; A second artificial operating device, wherein the sub-transmission is shifted from a high-speed position by the second artificial operating device while the main artificial transmission is being shifted to a certain shift position by the first artificial operating device. When the shift operation is performed to the low-speed position, the main transmission is automatically given priority over the shift control means so that the first shift position is higher than the shift position of the main transmission before the shift operation. First shifting means for shifting gears to In a state where the speed of the main transmission is shifted to a certain shift position by the first artificial operation tool and the speed of the auxiliary transmission is shifted from a low-speed position to a high-speed position by the second artificial operation tool, the shift is performed. A second transmission unit that automatically performs a shift operation of the main transmission device in preference to the transmission control unit so that the second transmission position is lower than the transmission position of the main transmission device before the operation; When the main transmission is shifted by the first artificial operation tool in a state where the forward / reverse switching device is switched to the neutral position, storage means for storing a shifted position of the main transmission that has been shifted. The operation of the first and second transmission means is prevented from being restrained based on the storage by the storage means, and the auxiliary transmission is moved from the low-speed position to the high-speed position or from the high-speed position to the low-speed position by the second artificial operation tool. Shifting Once created, automatically shift operation to the third speed change means and travel gear structure of the working vehicle that is provided with a priority to the main speed change device has been shift position stored in said storage means to said shift control means. 2. The third speed change means is configured such that, when an engine stop operation is performed, the speed change position stored in the storage means is erased, and the operation of the first and second speed change means is permitted. The traveling speed change structure for a working vehicle according to claim 1, wherein