JPH08338525A - Running transmission device for working vehicle - Google Patents

Abstract

PURPOSE: To prevent the occurrence of abnormal double meshing by stopping rotation of an upper side transmission shaft while causing a double mesning by means of a main transmission in case of shifting a second sub-transmission through stopping of a car body, and preventing shifting of a main clutch to a transmission side when the corresponding hydraulic clutch is not in an interruption state. CONSTITUTION: In order to perform transmission operation by means of a shift member 43 of a second sub-transmission device 12 through a transmission lever 28, all hydraulic clutches of a main clutch and a first sub-transmission device are driven to the transmission interruption side. Simultanenously, two or more hydraulic clutches of a main transmission device are driven to the transmission side. A double meshing (multiple transmission) state is generated by the main transmission device where transmission ratios are differentiated in two or more hydraulic clutches for controlling. In case that the hydraulic clutches under a double meshing state are not shifted to the transmission interruption side unil a specified time passes, operation of the main clutch to the transmission side is prevented and an alarm is started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling transmission system for a work vehicle such as a tractor.

[0002]

2. Description of the Related Art In a work vehicle such as a tractor, for example, as shown in FIG. 1, power from an engine 1 is transmitted to hydraulic multi-plate type main clutches 5 and 6, a main transmission 10, and a first auxiliary transmission 11. The main transmission 10 and the first sub transmission 11 are each configured to operate by supplying hydraulic oil to one of a plurality of hydraulic clutches and operating from the transmission cut-off side to the transmission side. The hydraulic clutch switching type is used.

In this case, for example, on the lower side of the first auxiliary transmission device 11, a second auxiliary transmission device 12 of the gear shift type, which is operated by a sliding operation of the shift member 53, is arranged, and the second auxiliary transmission device 12 is arranged. May be configured to run at a low speed.

[0004]

Generally, the gear shifting operation of the second auxiliary transmission of the gear shifting type for low speeds as described above is generally performed with the vehicle body stopped. Thus, for example, in the case of performing the gear shift operation of the second auxiliary transmission device 12 in the configuration of FIG. 1, the shift member 53 is generally operated by the gear shift lever in a state where the main clutches 5 and 6 are operated to the transmission interruption side to stop the vehicle body. The slide operation is performed to perform the shift operation of the second auxiliary transmission device 12.

Incidentally, the hydraulic clutch is provided between the transmission gear and the transmission shaft, and the transmission side means that the transmission gear and the transmission shaft are integrated by pressurization to be in a clutch-engaged state capable of transmitting power. Means In the above case, even if the main clutches 5 and 6 are operated to the transmission disengagement side, a so-called friction plate entrainment phenomenon occurs in the hydraulic multi-plate type main clutches 5 and 6, and the power of the engine 1 is increased by the main clutch 5. 6 to the main transmission 10 and the first transmission
It is transmitted from the sub transmission 11 to the second sub transmission 12.

As a result, although the lower transmission shaft of the second auxiliary transmission 12 is stopped (due to the stop of the vehicle body), the upper transmission shaft of the second auxiliary transmission 12 is slightly moved from the engine 1. It becomes a state that it is rotating by the power transmitted by each. Therefore, even if the shift member of the second auxiliary transmission is to be slid by the shift lever, the shift member slides due to the difference in rotational speed between the upper and lower transmission shafts due to the rotation of the upper transmission shaft. The operation may not be performed well, and the gear shift operation of the second auxiliary transmission by the gear shift lever may become heavy.

Such a problem is that when the gear shift lever is operated, the two hydraulic clutches of the main transmission are operated to the transmission side and all the other hydraulic clutches are operated to the transmission cutoff side when the operation is started. By doing so, it is possible to solve the problem by stopping the rotation of the power transmission shaft on the upper hand side by the double meshing of the two transmission gears in the main transmission (the state in which the transmission gears simultaneously become the transmission side).

However, the control valve of the hydraulic clutch to be double-engaged is not always fully operated, and an abnormality (inconvenience) such as a spud occurs to generate a hydraulic clutch that does not change from the transmission state to the transmission interruption state. The problem occurs. That is, when the shift operation of the second auxiliary transmission is completed by the shift lever and the hydraulic clutch of the shift target of the main transmission is operated to the transmission side and the main clutch is operated to the transmission side, the original double meshing is performed. The existing hydraulic clutch does not become the transmission disengaged state, and new double meshing may occur with the operated hydraulic clutch of the gear shift target.

According to the present invention, when the vehicle body is stopped and the speed change lever is used to change the speed of the second auxiliary transmission, a double meshing is caused in the main transmission to stop the rotation of the power transmission shaft on the upper hand side. Shifting to the transmission side of the main clutch when the hydraulic clutch that double-engages purposely in the main transmission is not in the transmission disengaged state while allowing the gear shift operation to be performed lightly It is an object of the present invention to provide a gear shift operation device for a work vehicle capable of preventing the occurrence of new double meshing involving the hydraulic clutch of the gear shift target.

Further, according to the present invention, after the transfer of the main clutch to the transmission side is blocked, the target of the hydraulic clutch which is the gear shift target in the main transmission is eliminated to prevent the transmission from being disengaged. It is an object of the present invention to provide a work vehicle gear shift operation device capable of ensuring traveling of the work vehicle by changing the double-mesh hydraulic clutch to the gear shift target.

[0011]

The first concrete means for solving the problems in the present invention is a hydraulic main clutch 5, 6 to which power from the engine 1 is transmitted;
A main transmission device 10 that shifts power from 6 by operating one of a plurality of hydraulic clutches to a transmission side.
A first sub-transmission device 11 that shifts power from the main transmission device 10 by operating one of a plurality of hydraulic clutches 26 and 27 to a transmission side; and a first sub-transmission device 1
The second sub-transmission device 12 that shifts the power from the gear 1 by sliding the shift member 53 by the shift lever 28.
And a gearshift lever 28 for gearshifting the second auxiliary gearbox 12.
The main clutches 5 and 6 and the hydraulic clutches 26 and 27 of the first subtransmission 11 are operated to the transmission disengagement side in accordance with the start of the operation of, and at least two of the hydraulic clutches of the main transmission 10 are set to the transmission side. A first control means that operates simultaneously; a required one of the hydraulic clutches 26 and 27 of the first auxiliary transmission device 11 is operated to the transmission side when the operation of the speed change lever 28 is completed,
Of the hydraulic clutches of the main transmission 10, one of the hydraulic transmissions in the simultaneous transmission state is operated to the transmission disengagement side, a required one is operated to the transmission side, and the operation of the main clutches 5 and 6 to the transmission side is allowed. Second control means; when the required hydraulic clutch of the hydraulic clutches of the main transmission device 10 is in the transmission state, it is detected that the one in the simultaneous transmission state is not in the transmission interruption state, and the main clutches 5, 6 And a third control means for preventing the shift to the transmission side.

The second concrete means for solving the problems in the present invention is, in addition to the first concrete means, a main transmission when the hydraulic clutch in the simultaneous transmission state is not in the transmission cutoff state. The fourth control means is provided for canceling the operation of the required hydraulic clutch 10 which is to be operated to the transmission side, and for operating the hydraulic clutch which has not been in the transmission disengaged state to the transmission side.

[0013]

Operation: As shown in FIGS.
When a shift operation is performed by sliding the shift member 53 of the second auxiliary transmission device 12 by means of the above, when the operation button 57 is released and the shift operation by the shift lever 28 is started, the first control means operates. , Primary clutch 5, 6 and first
All the hydraulic clutches 26 and 27 of the sub transmission 11 are operated to the transmission interruption side (in the first sub transmission 11,
The hydraulic clutch operated on the transmission side is operated on the transmission interruption side, and the hydraulic clutch operated on the transmission interruption side is held on the transmission interruption side). At the same time, the main transmission 1
Of the 0 hydraulic clutches 21, 22, 23, 24, two or more hydraulic clutches are operated to the transmission side.

In a state where the main clutches 5 and 6 are operated to the transmission cutoff side, the power of the engine 1 is transmitted through the main clutches 5 and 6 due to the accompanying phenomenon of the main clutches 5 and 6, and the main shift on the lower side is performed. It is assumed that the information is transmitted to the device 10 little by little. In this case, two or more hydraulic clutches in the main transmission 10 are operated to the transmission side, and the main transmission 10 is operated by two transmission clutches.
Since two or more hydraulic clutches are in a double meshing state (multiple transmissions) having different transmission ratios and are in a braking state, the power is stopped in the main transmission device 10 and the accompanying phenomenon in the main clutches 5 and 6 occurs. Can also be stopped.

Since all the hydraulic clutches 26 and 27 of the first auxiliary transmission 11 are operated to the transmission interruption side, in the second auxiliary transmission 12 the lower side (travel device 1).
Even if the transmission shafts (4, 19 side) are stopped due to the stop of the vehicle body, the transmission shafts on the upper side (the first auxiliary transmission device 11 side) are stopped in a freely rotatable state. Therefore, in a state in which power is not transmitted to the shift member 53 of the second subtransmission device 12 (a surface pressure is not applied to the engagement portion of the shift member 53 by the power of rotation), the second subtransmission device is operated by the shift lever 28. Since the sliding operation of the shift member 53 of 12 can be performed lightly, even if the phase of the occlusal portion of the shift member 53 does not match, the sliding operation of the shift member 53 causes the second auxiliary transmission device 12 to operate at the upper side (first side). 1 sub-transmission 11 side) the transmission shaft slightly rotated and the phases matched,
The shift member 53 can be lightly slid to be engaged.

After the above operation, when the operation button 57 is held and the shift operation of the second auxiliary transmission 12 by the shift lever is completed, the second control means is actuated and the first control means is operated.
One hydraulic clutch required (shift target) of the sub transmission 11 is operated to the transmission side, and two or more hydraulic clutches operated to the transmission side of the main transmission 10 are operated to the transmission disengagement side. One hydraulic clutch (shift target) is operated to the transmission side, operation of the main clutches 5 and 6 to the transmission side is permitted, and the main transmission device 10 and the first auxiliary transmission device 11 are operated.
Returns to the state where power can be transmitted.

In a normal case, the gear shifting operation is completed by the above-mentioned operation, but the hydraulic clutch in the double meshing state in the main transmission 10 is maintained within a certain time (for example, 100 ms) after the operation button 57 is held. Is unable to shift to the transmission cutoff side due to the stick of the control valve or the like, the pressure sensor 74 detects that the hydraulic pressure of the hydraulic clutch in the double meshing state which is not the shift target is activated by the operation of the third control means, The operation of the main clutches 5 and 6 on the transmission side is blocked, and the alarm 78 is activated.

At this time, even if the hydraulic pressure is applied to the gear shift target hydraulic clutch of the main transmission 10, the main clutches 5 and 6 remain in the transmission cut-off state, so that power is not transmitted and double meshing does not occur. When the operator returns the gear shift lever 28 to the neutral stop position N by the operation of the alarm device 78 and then repeats the gear shift operation of the second auxiliary transmission device 12 by the gear shift lever 28, the fourth control means operates and the main control unit operates. The shift target of the transmission 10 is changed so that the hydraulic pressure is changed to a hydraulic clutch that does not return while standing up, and the main clutches 5 and 6 can be operated to the transmission side.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. 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.
Is transmitted to the PTO shaft 4 via the transmission shaft 2 and the hydraulic multi-plate PTO clutch 3.

Power from the engine 1 is supplied to the forward clutch 5 or the reverse clutch 6, the cylindrical shaft 7, the main transmission 10,
It is transmitted to the left and right rear wheels 14 (traveling device) via the first auxiliary transmission 11, the second auxiliary transmission 12, and the rear wheel differential device 13. On the other hand, the power branched from immediately before the rear wheel differential device 13 is the transmission shaft 15 and the hydraulic clutch type front wheel transmission device 1.
6, transmitted to the left and right front wheels 19 (travel device) via the front wheel transmission shaft 17 and the front wheel differential device 18.

The forward clutch 5 and the reverse clutch 6 are hydraulic multi-plate type which is a combination of a friction plate and a piston (not shown), and is selectively operated to the transmission side by supplying hydraulic oil through a control valve. To be done. That is, 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 vehicle body moves backward.

The main transmission 10 includes a plurality of hydraulic clutches (four in the embodiment) such as a hydraulic multi-plate type first speed clutch 21, second speed clutch 22, third speed clutch 23 and fourth speed clutch 24 arranged in parallel. It is possible to shift to 4 steps,
By selectively operating the first-speed to fourth-speed clutches 21 to 24 on the transmission side, the power from the cylindrical shaft 7 on the engine 1 side is shifted in four stages and transmitted to the transmission shaft 25 on the lower side. It is like this.

The first sub-transmission device 11 also has a low speed clutch 26 and a high speed clutch 27, which are two multi-plate hydraulic clutches, arranged in parallel to each other so that the speed can be changed between high and low stages. By selectively operating to the transmission side, the power from the transmission shaft 25 on the main transmission device 10 side is shifted in two steps and transmitted to the second auxiliary transmission device 12 on the lower side.

The second sub-transmission device 12 is of a synchromesh type in which the shift member 53 is slid, and is capable of shifting in two high and low stages.
A manual mechanical gear shift operation is performed by 8. Next, devices such as the forward and reverse clutches 5 and 6, the main transmission device 10 and their hydraulic circuits will be described.

As shown in FIG. 3, forward and reverse clutches 5, 6 are provided in the first oil passage 30 directly connected to the pump 29.
To the solenoid proportional valve 35 and pilot operated switching valves 36a and 37a, and pilot operated switching valves 31a to the first to fourth speed clutches 21 to 24 of the main transmission 10.
32a, 33a, 34a, solenoid proportional valves 38, 3 for the low speed and high speed clutches 26, 27 of the first auxiliary transmission device 11.
Control valves such as 9 are connected in parallel.

On the other hand, in the second oil passage 40 branched from the first oil passage 30, the pilot operated switching valve 42a for the hydraulic clutch 41 for the diff lock operation in the front wheel diff device 18 and the diff lock operation in the rear wheel diff device 13 are provided. Operated switching valve 4 for hydraulic clutch 43 for vehicle
4a, the standard clutch 45 of the front wheel transmission 16, and the speed increasing clutch 46 (see FIG. 1) are connected in parallel with control valves such as pilot operated switching valves 47a and 48a.

Each switching valve 31a-34a, 36a, 37
a, 42a, 44a, 47a, and 48a are urged to the oil discharge side (transmission cut-off side) by springs, and are operated to the supply side (transmission side) by supplying pilot hydraulic oil as described later. To be done. The pilot oil passage 50 is branched from the first oil passage 30 via the pressure reducing valve 49.
0 is the switching valves 31a to 34a, 36a, 37a, 42a,
44a, 47a, and 48a are connected to the operation portions of the switching valves, and the solenoid operated valves 31b, 32b, and 33 are connected to the operation portions of the respective switching valves.
b, 34b, 36b, 37b, 42b, 44b, 47
b and 48b are connected.

Each solenoid operated valve 31b-34b, 36b, 3
7b, 42b, 44b, 47b, 48b are urged to 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 valve 31a.
~ 34a, 36a, 37a, 42a, 44a, 47a,
It is supplied to the operation part of 48a, and these are operated to the supply side (transmission side).

Next, the construction of the operation parts of the forward and reverse clutches 5, 6, the main transmission 10, etc. will be described. FIG.
As shown in FIG. 3, an opening / closing valve 51 capable of draining pilot working oil from the operating portions of the switching valves 36a, 37a of the forward and reverse clutches 5, 6 is provided, and the opening / closing valve 51 is biased to the closing side by a spring. A clutch pedal 52 for mechanically operating the open / close valve 51 to the open side is provided.

Further, a forward / backward lever 59 is provided at the base of the steering wheel 58 for the front wheels 19 to emit an electric forward signal and a backward signal. As shown in FIG. 2, the gearshift lever 28 is swingably supported around the axis of the horizontal axis in the control section of the vehicle body, and the shift fork 54 and the gearshift lever 28 for sliding the shift member 53 of the second auxiliary transmission device 12 are slidably operated. And are mechanically interlocked by a linkage mechanism 55.
Therefore, by switching the speed change lever 28 to the three speed change positions of the neutral stop position N, the low speed position L, and the high speed position H, the second auxiliary transmission device 12 can be operated in two high and low stages.

A pair of limit switches 9 are provided on the front and rear sides of the speed change lever 28 to detect whether the low speed position L or the high speed position H is being operated. A lock pin 56 that projects outward and is movable up and down is provided in the middle of the shift lever 28, and an operation button 57 for moving the lock pin 56 up and down is provided on the upper portion of the shift lever 28. The lock mechanism is formed by these.

The lock pin 56 is urged by a spring (not shown) so as to move to the holding position above the plane of FIG. 2 (the operation pin 57 is also urged to the left side of the plane of the drawing). By engaging 56 with the fixed side guide plate 60, the shift lever 28 is held at each of the neutral stop position N, the low speed position L, and the high speed position H. Then, when the operation pin 57 is pushed in, the lock pin 56 is moved to the holding release position on the lower side of the paper surface, and the shift lever 28 can be operated to the neutral stop position N, the low speed position L and the high speed position H.

A shift-up button 61 and a shift-down button 62 are vertically arranged on the left lateral side of the shift lever 28. As will be described later, when the shift-up button 61 and the shift-down button 62 are pressed once, the Two shift up signals and shift down signals are transmitted,
The gear shift operation of the main and first auxiliary transmissions 10 and 11 is performed.

As shown in FIG. 2, a 7-segment shift display portion 64 for displaying shift positions (first speed to eighth speed) of the main transmission device 10 and the first auxiliary transmission device 10, and the forward / reverse lever 5 are shown.
A forward lamp 65 and a reverse lamp 66 which indicate which of the forward and reverse clutches 5 and 6 is operated to the transmission side by 9 and a neutral stop lamp 67 which indicates that the speed change lever 28 is operated to the neutral stop position N. And are provided in the control section.

Further, as shown in FIG. 3, a pressure sensor 74 for detecting whether or not the operating pressure of the forward and reverse clutches 5, 6 has reached a predetermined pressure on the transmission side is provided. Upon detection of 74, the forward and reverse lamps 65 and 66 are turned on. Next, the shift lever 28
Shift up button 61 and shift down button 62
The gear shift operation and the device will be described.

3 and 4, when the forward / backward lever 59 is operated to the forward position F (step S1), an operation current is sent to the electromagnetic operation valve 36b (step S2), and the switching valve 36a is moved to the supply side. The forward clutch 5 is operated to the transmission side, and the forward lamp 65 is turned on (step 3). On the contrary, when the forward / reverse lever 59 is operated to the reverse position R (step S1), the operation current is sent to the electromagnetic operation valve 37b (step S4), the switching valve 37a is operated to the supply side, and the reverse clutch 6 is operated. Is operated to the transmission side, the reverse lamp 66 is turned on (step S5), and the buzzer 71 in FIG. 2 is operated intermittently (step S6).

As shown in FIG. 1, the main transmission 10 is capable of shifting in four stages and the first sub-transmission 11 is capable of shifting in two stages. A total of eight gears can be shifted. In this case, the first to fourth speed clutches 21 to 2 of the main transmission 10 are operated while the low speed clutch 26 of the first auxiliary transmission 11 is being operated to the transmission side.
4 corresponds to the shift positions of the 1st speed to the 4th speed, and the 1st speed to the 4th speed clutch of the main transmission 10 while the high speed clutch 27 of the first auxiliary transmission 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, these operating pressures are transmitted to the first to fourth speed clutches 21 to 24 of the main transmission device 10, and the low speed and high speed clutches 26 and 27 of the first auxiliary transmission device 11, respectively. Each pressure sensor 74 is provided with a pressure sensor 74 for detecting whether or not a predetermined pressure on the side has been reached.
Is detected, the current shift positions (first speed to eighth speed) of the main transmission 10 and the first auxiliary transmission 11 are detected, and the detected shift positions are displayed on the shift display portion 64 (step S7).

Next, the speed change lever 28 shown in FIG.
Alternatively, when the shift lever 28 is operated to the high speed position H (step S8), the shift up button 61 or the shift down button 62 of the shift lever 28 is pushed once (steps S9 and S10). Then, the solid line A1 in FIG.
As shown in 1), when the shift-up button 61 is pressed, the electromagnetically operated valves 31b to 3b for the main transmission 10 at the gear shift position one step higher than the current gear shift position.
When the shift down button 62 is pressed, on the contrary, when the operation current starts to be supplied to 4b, the main transmission 10 at the shift position one speed lower than the current shift position.
The operation current starts to be supplied to the electromagnetic operation valves 31b to 34b for use (step S11).

At the same time, the solid line A2 in FIG. 5 (time point B1)
As shown in, the electromagnetic proportional valves 38, 39 of the low speed or high speed clutches 26, 27 operated on the transmission side in the first auxiliary 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 S12).

In this case, when the gear shift operation is performed from the fourth gear shift position to the fifth gear shift position, the operating pressure of the low speed clutch 26 of the first auxiliary transmission device 11 is reduced to zero and the high speed clutch 27 is actuated. The pressure is raised from zero to a predetermined low pressure P3. On the contrary, when the gear shift operation is performed from the fifth gear shift position to the fourth gear shift position, the working pressure of the high speed clutch 27 of the first auxiliary transmission device 11 is reduced to zero, and the working pressure of the low speed clutch 26 becomes zero. To a predetermined low pressure P3.

Then, as shown by the solid line A1 in FIG. 5 (from time B2 to time B3), the operating pressure of the first-speed to fourth-speed clutches 21 to 24 on the one-speed high speed side or the one-speed low speed side in the main transmission device 10 is increased. The solenoid operated valves 31b to 34b are operated to raise the operating pressure P1 in the transmission state. At the same time, as shown in FIG.
As indicated by the alternate long and short dash line A3 (time point B2 to time point B3), the operating pressure of the first to fourth speed clutches 21 to 24 before pressing the shift up button 61 or the shift down button 62 in the main transmission device 10 is: Solenoid operated valves 31b-34
The operating pressure P1 in the transmission state is lowered to zero by b (step S13).

Next, the first pressure that was maintained at a predetermined low pressure P3
The operating pressure of the low speed or high speed clutches 26, 27 of the auxiliary transmission 11 is gradually increased by the solenoid proportional valves 38, 39 as shown from time B3 to time B4 on the solid line A2 in FIG. , Low or high speed clutches 26, 27
Operating pressure reaches the operating pressure P2 in the transmission state (step S
14).

In this case, from the time point B3 to the time point B4 of the solid line A2 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, and the low speed side (first speed side). The shift position of) is such that the operating pressure from time B3 to time B4 is rapidly increased in a short time. As described above, the shift up button 6
1 or the shift operation by pressing the shift down button 62 is completed, and when the shift operation is completed,
The gear shift position after the gear shift operation is displayed on the gear shift display section 64 (step S15), and the buzzer 71 operates only once,
The operator is notified of the end of the gear shifting operation (step S1).
6).

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.
Unless the 1 or shift down button 62 is once returned and pushed again, the next shift operation is not performed.
Next, a gear shifting operation to the neutral stop position N, the low speed position L and the high speed position H and the device of the speed change lever 28 shown in FIG. 2 will be described.

The gear shift lever 28 is held by the lock pin 56 at any one of the neutral stop position N, the low speed position L and the high speed position H. When the gear shift lever 28 is operated to another position, the gear shift lever 28 is operated. It is necessary to release the holding by the lock pin 56 by pushing the operation pin 57.
In this case, as shown in FIG. 6, while the shift lever 28 is operated to the low speed position L and the forward / reverse lever 59 is operated to the forward position F (the forward clutch 5 is operated to the transmission side, the reverse clutch 6 is operated). Is operated to the transmission cutoff side, shift up button 61 and shift down button 6
2 to the second speed shift position (the second speed clutch 22 of the main transmission 10 and the low speed clutch 2 of the first auxiliary transmission 11).
6 is set to be operated on the transmission side) and the vehicle is traveling.

From this state, it is assumed that the clutch pedal 52 is depressed to operate the forward clutch 5 to the transmission interruption side to stop the vehicle body. After that, when the operation button 57 of the speed change lever 28 is pushed (holding release) and the lock pin 56 is removed downward from the guide plate 60 (time C1), the second speed clutch 22 and the first speed clutch 22 of the main speed change device 10 are operated. Sub transmission 1
The low speed clutch 26 of No. 1 is operated to the transmission interruption side.

The forward clutch 5 has already been operated to the transmission cutoff side by depressing the clutch pedal 52, but the clutch pedal 5 is operated while the operation button 57 is being pressed.
Even if 2 is returned, the forward clutch 5 is held on the transmission cutoff side. At the same time, the first speed and fourth speed clutches 21 and 24 of the main transmission 10 are simultaneously operated to the transmission side (time points C1 and C2) (corresponding to the first control means).

As described above, in the state where the forward clutch 5 is operated to the transmission cut-off side, the power of the engine 1 passes through the forward clutch 5 due to the accompanying phenomenon of the forward clutch 5, and the main transmission on the lower side via the forward clutch 5. Suppose that it is transmitted to 10 little by little. In this case, in the main transmission 10, the first speed and the fourth speed set for double meshing (simultaneous meshing, multiple meshing)
Both the speed clutches 21 and 24 are operated to the transmission side,
Since the main transmission 10 is in a double meshing transmission state with different transmission ratios in the 1st and 4th speed clutches 21 and 24 and is in a braking state, the power is stopped in the main transmission 10 and the forward movement is performed. The accompanying phenomenon in the clutch 5 can also be stopped.

Therefore, the power is not transmitted to the shift member 53 of the second auxiliary transmission 12 (the shift member 5
The gear shift lever 28 can be lightly operated from the low speed position L to the neutral stop position N side with the operation button 57 being pressed (holding released) in the state where the surface pressure is not applied to the occlusal portion of 3 by the power of rotation). . When the shift lever 28 is operated to the neutral stop position N and then the operation button 57 is returned (held) (at time C3), the shift lever 28 is held at the neutral stop position N by the lock pin 56, and the main transmission 10 is moved to the 1st position. The first and fourth speed clutches 21 and 24 are operated to the transmission interruption side, and the original second speed clutch 22 of the main transmission device 10, the original low speed clutch 26 of the first auxiliary transmission device 22 and the original forward clutch 5 are moved to the transmission side. Operated.

Next, after operating the shift lever 28 to the neutral stop position N, the operation button 57 is pressed again (holding release).
Then, similarly to the above, the second speed clutch 2 of the main transmission 10 is
2, the low speed clutch 26 and the forward clutch 5 of the first auxiliary transmission 11 are operated to the transmission interruption side, and
The fourth speed and fourth speed clutches 21 and 24 are operated to the transmission side (time points C4 and C5) (corresponding to the first control means).

If the operation button 57 is held in the pressed state (hold release) when the speed change lever 28 is operated to the neutral stop position N, the second speed clutch 2 of the main speed change device 10 is held.
2, the low speed clutch 26 and the forward clutch 5 of the first auxiliary transmission 11 are operated to the transmission interruption side, and
The state in which the high speed and fourth speed clutches 21 and 24 are operated to the transmission side is maintained.

In this way, if the first and fourth speed clutches 21 and 24 are operated to the transmission side in the main transmission 10, the power is stopped in the main transmission 10 and the forward clutch 5 is rotated in the same manner as described above. The phenomenon can be stopped. In this case, the low-speed and high-speed clutches 26 and 27 of the first auxiliary transmission 11 shown in FIG. 1 are also operated to the transmission interruption side, so that in the second auxiliary transmission 12, the lower side (the front wheel 19 and the rear wheel 1).
The transmission shaft on the 4th side is stopped (due to the stop of the vehicle body), whereas the transmission shaft on the upper side (the first auxiliary transmission 11 side) is stopped in a freely rotatable state.

As a result, when the operation lever 57 is pushed (holding is released) and the shift lever 53 is engaged from the neutral stop position N to the high speed position H, the phases of the occlusal parts are matched. Even if not done, the second auxiliary transmission device 12 may be moved along with the sliding operation of the shift member 53.
, The transmission shaft on the hand side (first auxiliary transmission device 11 side) slightly rotates and the phases match, and the shift lever 28 can be lightly operated from the neutral stop position N to the high speed position H.
Can be occluded.

Next, when the speed change lever 28 is operated from the neutral stop position N to the high speed position H and the operation button 57 is returned (held) (time C6), the speed change lever 28 is moved to the high speed position H by the lock pin 56. Retained. In this case, unlike the state in which the operation button 57 is returned (held) while the speed change lever 28 is operated to the neutral stop position N, the first and fourth speed clutches of the main gear transmission 10 for double meshing are first described. 21 and 24 are operated to the transmission cutoff side, and the clutch of the shift target of the main transmission 10 (any one of 21 to 24) and the clutch of the shift target of the first auxiliary transmission 11 (26, 2).
7) is operated to the transmission side (time point C6),
The forward clutch 5 is not operated to the transmission side yet (corresponding to the second control means).

In the transmission of the present invention, the main transmission 10 has four speeds, the first auxiliary transmission 11 has two high and low speeds, and the second
The sub-transmission device 12 is capable of shifting gears in a total of 16 high and low stages, and the second sub-transmission device is selected from the state where the second sub-transmission device 12 is set to the low speed side and, for example, the eighth shift position is selected. 12
If the shift position is changed to the 16th speed position when the gear shift operation is performed to the high speed side, the change in the vehicle speed becomes too large. In many cases, the vehicle speed required during agricultural work is the ninth speed after the eighth speed.

Therefore, in the second control means, when the second subtransmission device 12 is switched from low speed to high speed or vice versa, the control device S controls so that the changed shift position becomes the smallest, and the main shift is performed. Clutch of device 10 (21-
24) and the clutches (26, 2 of the first auxiliary transmission 11)
7) is changed from the transmission side until then to the shift target, and the clutch of the shift target becomes the transmission side.

However, when the shift lever 28 is at the neutral stop position N, it is possible to operate the shift up button 61 or the shift down button 62 to shift from, for example, the eighth speed to the sixteenth speed. In this case, even if the second auxiliary transmission 12 is operated to change gears, the transmission-side clutches in the main transmission 10 and the first auxiliary transmission 11 remain unchanged.

When the shift target clutch of the main transmission device 10 and the shift target clutch of the first auxiliary transmission device 11 are operated almost completely to the transmission side (time C7), then the forward clutch 5 is gradually changed. It is operated by the transmission side. In this case,
Further, as shown in FIG. 2, a rotation speed sensor 73 for detecting the rotation speed of the cylindrical shaft 7 is provided between the forward and reverse clutches 5 and 6 and the main transmission 10, and the forward clutch 5 is operated on the transmission side. From the time point C7 when the engine is started, the rotation speed sensor 73
The operating pressure of the forward clutch 5 is increased by the solenoid proportional valve 35 shown in FIG. 3 so that the rate of increase of the detected value does not exceed the set value, and the vehicle is smoothly started by operating to the transmission side. Go (time point C8).

At the aforementioned time point C7, the clutch pedal 5
When the pedal 2 is depressed, the forward clutch 5 is held on the transmission cutoff side by the open / close valve 51 and the switching valve 36a shown in FIG. Therefore, by slowly returning the clutch pedal 52 after the time point C8 passes, the forward clutch 5 can be artificially operated to the transmission side to smoothly start the vehicle body.

The gear shifting operation of the gear shift lever 28 is as follows.
It is possible to operate from the low speed position L to the high speed position H or vice versa without pressing the operation button 57 in the holding release state without temporarily stopping at the neutral stop position N. In that case, the time point C1 in FIG. To fly to time point C4 at once. By the way, when the transmission disconnection side operation of the 1st speed and 4th speed clutches 21 and 24 of the main gearbox 10 for double meshing by the second control means is performed, the confirmation is that those pressure sensors 74 turn off the pressure. It is performed by detecting, but if the pressure OFF is not detected even after a set time (for example, about 100 ms, the time can be changed) after the operation button 57 is released and the holding state is achieved, The control means 3 starts operating (indicated by a dotted line from the time point C10 in FIG. 6 toward the rear).

The switching valves 31a and 34a and the solenoid operated valves 31b and 34b of the first and fourth speed clutches 21 and 24 are abnormal (inconvenient) such as stick due to dust entering or catching.
It is difficult to completely prevent such an abnormality, and even if a command signal to the transmission cutoff side is received, the spool may not return to its original state due to the inconvenience as described above.

In such a case, the pressure sensor 74 detects the pressure-on state and transmits a signal to the control device S to prevent the main clutches 5 and 6 from shifting from the transmission interruption side to the transmission side, or Hold the transmission cutoff state. At the same time, as shown in FIG. 6, the alarm 78 is activated to notify the operator by blinking the shift indicator lamp, activating an alarm buzzer, or the like. This alarm 78, instead of having a separate one,
The gear change display portion 64 may blink and the buzzer 71 may be operated.

That is, in the control unit S, the switching valves 31a, 34
The operation signal of a and the pressure signal from the pressure sensor 74 are compared to determine whether they are normal. If they are abnormal, the electromagnetic operation valves 36b and 37b of the main clutches 5 and 6 are demagnetized. This prevents unintended double meshing, that is, abnormal double meshing. The operator notifies the shift lever 28 by the notification.
Is returned to the neutral stop position N (time point C11), the control device S
Resets the shift target by the second control means, switches the shift target to the clutch in which the abnormality has occurred, sends an operation signal to the switching valve for the clutch, and fixes the clutch on the transmission side.

Next, when the speed change lever 28 is put into the high speed side or the low speed side, the clutch of the changed speed change target shifts to the transmission side, and the main clutches 5 and 6 become operable to the transmission side ( Fourth control means). The fourth control means may energize the switching valve of the abnormal clutch again to give pushing force to the spool, whereby the stick or the like may be broken. If the failure is resolved, the next shift operation returns to normal, and even if the failure is not resolved, only the traveling of the work vehicle can be secured.

When both the two clutches 21 and 24 that perform the purposeful double meshing are abnormal during the operation of the third control means, one of the clutches is switched to the gear shift target.
However, since the other clutch also has an abnormality, the control device S sets the other clutch as the next gear shift target, and the main clutches 5, 6 are simply repeated.
Can not be the transmission side, the work vehicle stops, and it is possible to prevent failures such as gear damage due to abnormal double meshing of the transmission.

In the control device S, the occurrence of spud or the like is extremely small in the second and third speed clutches that do not perform the purposeful double meshing, but pressure is detected also in these clutches and an abnormality occurs between the two. If so, it is desirable that the third and fourth control means operate to prevent abnormal double meshing. The present invention is not limited to the above embodiment, but can be variously modified. For example, the main clutches 5 and 6 may be one clutch that only connects and disconnects power, and the main transmission 10 may be one that shifts to two, three, or five or more gears, and is a hydraulic clutch that performs a purposeful double meshing. May be the second and third speed clutches 22, 23 or three or more clutches.

[0068]

According to the present invention described in detail above, the gear shift lever in a state in which the vehicle body is stopped by setting the two hydraulic clutches of the main transmission device in the double meshing state to stop the upper transmission shaft Thus, the gear shift operation of the second auxiliary transmission can be performed lightly and smoothly, the gear shifting performance of the work vehicle can be improved, and the hydraulic clutch of the gear shift target of the main gear shifts to the transmission side. Even if an abnormality occurs in which the original double-engaged hydraulic clutch does not go into the transmission disengaged state, the main clutch is prevented from shifting to the power transmission side, preventing an abnormal double-engagement involving the hydraulic clutch of the gear shift target. it can.

Further, when the new abnormal double meshing is about to occur, the targeting of the hydraulic clutch which is the gear shift target in the main transmission is eliminated, and the original double clutch that is not in the transmission cut-off state is eliminated. Even if an abnormality occurs in one hydraulic clutch by changing the meshing hydraulic clutch to the gear shift target, the abnormal hydraulic clutch can be used to shift the main clutch to the transmission side. Driving can be secured.

[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 a second auxiliary transmission device, a shift display portion, and a linked state of each portion.

FIG. 3 is a hydraulic circuit diagram of a main transmission, a first auxiliary transmission, 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 with a shift up button and a shift down button of a shift lever.

FIG. 6 is a diagram showing a state of each part when the second sub-transmission device is gear-shifted by a gear shift lever and an operation button.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 5, 6 Main clutch 10 Main transmission 11 First sub-transmission 12 Second sub-transmission 21, 22, 23, 24 Main transmission hydraulic clutch 26, 27 First sub-transmission hydraulic clutch 28 Second Shift levers of the sub transmission 31b, 32b, 33b, 34b Control valves of the main transmission 38, 39 Control valves of the first sub transmission 53 Shift members of the second sub transmission 56, 57 Shift lever locking mechanisms L, N , H Gear shift position S Control device

Claims (2)

[Claims] 1. A hydraulic main clutch (5) (6) to which power from an engine (1) is transmitted; and a main clutch (5).
A main transmission (10) that shifts the power from (6) by operating one of a plurality of hydraulic clutches to a transmission side; and a power from the main transmission (10) to a plurality of hydraulic pressures. A first sub-transmission device (1) that shifts gears by operating one of the clutches (26) (27) to a transmission side.
1) and; a second sub-transmission device (12) that shifts power from the first sub-transmission device (11) by sliding operation of a shift member (53) by a shift lever (28); and a second sub-transmission device ( The main clutches (5) and (6) and the hydraulic clutches (26) and (27) of the first sub-transmission device (11) are operated to the transmission cut-off side with the start of the operation of the speed change lever (28) for speed-changing the gear (12). And a first control means for simultaneously operating two or more of the hydraulic clutches of the main transmission (10) to the transmission side; the operation of the speed change lever (28) ends the operation of the first auxiliary transmission (11). A required one of the hydraulic clutches (26) and (27) is operated to the transmission side, and one of the hydraulic clutches of the main transmission (10) which is in the simultaneous transmission state is operated to the transmission cutoff side, and the required 1 Operation of the main clutch (5 When the required hydraulic clutch of the hydraulic clutch of the main transmission unit (10) is transmission state; second control means and to permit the operation to the transmission side (6)
And a third control means for detecting that the one in the simultaneous transmission state does not become a transmission cutoff state and for preventing the main clutches (5) and (6) from shifting to the transmission side. Car drive transmission. 2. When the hydraulic clutch in the simultaneous transmission state is not in the transmission disengagement state, the operation to the required hydraulic clutch which is to be operated to the transmission side of the main transmission (10) is canceled, and The traveling speed change device for a work vehicle according to claim 1, further comprising a fourth control means for operating a hydraulic clutch that has not been in a transmission cutoff state to a transmission side.