JP2000074212A - Shifting device for traveling of work vehicles - Google Patents

Abstract

(57) Abstract: In a work vehicle provided with a traveling transmission device in which a main transmission and a subtransmission are connected, a subtransmission that does not easily cause a shift shock and a shortage of drive speed can be performed. SOLUTION: The rotation output of a main transmission 20 capable of eight-speed shifting by switching of six clutches 21 to 26 is transmitted through front and rear wheels via an auxiliary transmission 30 capable of shifting to a high and low speed two-stage by changing a shift gear 30a. To 1 and 2.
When the speed of the sub-transmission 30 is shifted to the high-speed side after switching from the high-speed side to the low-speed side, the speed of the main transmission 20 when the sub-transmission 30 was previously at the high-speed side is lower than the third speed. In this case, when the main transmission 20 is operated to that shift speed, and when the speed of the main transmission 20 was 4th speed or higher when the sub-transmission 30 was previously on the high speed side, Then, the main transmission 20 is automatically shifted to the third speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a traveling transmission having a main transmission which can be shifted to a plurality of speeds and an auxiliary transmission which can be shifted to a high speed and a low speed.
The present invention relates to a shift control unit that shifts a main transmission device based on a shift command from a main shift operation device, and a shift operation device for traveling of a work vehicle including an auxiliary shift operation device that performs a shift operation of an auxiliary transmission device.

[0002]

2. Description of the Related Art In the above-mentioned work vehicle, a main transmission is operated by a main transmission, and a subtransmission is operated by an auxiliary transmission separately from the main transmission. And
For example, when the main transmission is capable of shifting to eight speeds, the overall speed is eight when the auxiliary transmission is shifted to a lower speed and eight when the auxiliary transmission is shifted to a higher speed. The gear can be shifted to a total of 16 speeds.
If the subtransmission is shifted from the low speed side to the high speed side in the high speed state, the overall speed is greatly increased from the fourth speed to the twelfth speed. For this reason, in the prior art, for example,
As described in JP-A-258583, when the sub-transmission is shifted from the low speed side to the high-speed side, the main transmission device is given priority over the shift control means in the lower gear stage than the sub-transmission stage. In some cases, the shift operation is automatically performed so that the sub-shift can be performed while suppressing the shift shock.

[0003]

Conventionally, when the main transmission is in a relatively low-speed gear stage and a sub-shift from the low-speed side to the high-speed gear is performed, the main transmission starts from the gear position before the sub-transmission. Further, the speed may be shifted to the low speed side and the speed may not be obtained in spite of the sub speed shifting to the high speed side. SUMMARY OF THE INVENTION It is an object of the present invention to provide a shift operation device for a traveling vehicle of a work vehicle capable of not only performing a sub-shift so that a shift shock does not easily occur, but also performing a sub-shift so that the above-described problem does not easily occur.

[0004]

The constitution, operation and effect of the invention according to claim 1 are as follows.

[0005] [Structure] A traveling transmission is provided in which a main transmission that can shift to a plurality of speeds and an auxiliary transmission that can shift to a high speed and a low speed are connected in series. A speed change control means for shifting the speed of the main transmission based on a command, and a speed change operation device for traveling of a work vehicle including an auxiliary speed change operation tool for operating the speed change of the auxiliary speed change device. When the speed is shifted to a high speed side, a check means is provided which automatically operates the main speed change device prior to the shift control means so as not to be higher than the set shift speed.

[Operation] When the subtransmission is shifted to the high-speed side, the shift speed at which a shift shock does not easily occur even if the main transmission is provided is set as the set shift speed. Then, if the main transmission is in a higher gear position than the set gear position before the sub-gear shift, if the sub-gear is shifted to a higher gear speed, the main transmission device will be brought into the set gear position by the action of the restraint means. The transmission is automatically shifted to a state in which a shift shock hardly occurs. If the main transmission is in a lower gear position below the set gear position before the subtransmission, the main transmission device is actuated by the restraint means even when the subtransmission is shifted to a higher gear position. The shift stage is maintained, and the transmission can be performed at a higher speed than in the related art that is shifted to a lower speed side than the shift stage.

[Effect] Even if the sub-shift is performed to the high speed side, the main transmission is set to a shift stage in which a shift shock does not easily occur, so that the vehicle can travel with a good riding comfort and light speed. If the main transmission is at the lower gear before the sub-shift, the main transmission will remain at that speed even if the sub-shift is performed at a higher speed, and the traveling device will be driven at a relatively high speed. You can work efficiently, such as running at high speed.

The structure, operation and effect of the invention according to claim 2 are as follows.

In the structure according to the first aspect of the present invention, when the auxiliary transmission is shifted from the high speed side to the low speed side and then shifted to the high speed side, the sub transmission was previously set to the high speed side. If the gear stage of the main transmission at that time is a gear higher than the set gear, the check means shifts the main gear to the set gear in preference to the shift control means, When the sub-transmission is shifted from the high-speed side to the low-speed side and then shifted to the high-speed side, the shift speed of the main transmission when the sub-transmission was previously at the high-speed side is greater than the set shift speed. When the shift speed is on the low speed side, the restraint means shifts the main transmission to the shift speed prior to the shift control means.

[Operation] When the sub-transmission is shifted to the high speed side, the automatic transmission of the main transmission is performed by the check means based on the gear position of the main transmission when the sub-transmission was previously set to the high speed side. . That is, if the speed of the main transmission when the auxiliary transmission was previously on the high speed side is higher than the set speed, the speed is automatically shifted to the set speed and a shift shock hardly occurs. If the gear is lower than the set gear, the gear is left as it is and a relatively high-speed transmission is possible.

[Effect] Even if the main transmission is shifted to a high speed side, the main transmission is in a gear position where shift shock is unlikely to occur and the vehicle can travel comfortably and speedily, or the main transmission is operated at the previous high speed. The gears at the time of traveling can be maintained, and the traveling device can be driven at a relatively high speed to perform high-speed traveling, thereby enabling efficient work.

The structure, operation and effect of the invention according to claim 3 are as follows.

[Structure] In the structure according to the first or second aspect of the present invention, when the auxiliary transmission is shifted from the low speed to the high speed and then shifted to the low speed, the auxiliary transmission is shifted to the low speed last time. The speed change means of the main transmission is provided with a speed adjusting means for shifting the speed of the main transmission prior to the shift control means.

[Operation] Even if the main transmission is shifted from the high-speed gear before the sub-shift to the set gear as the auxiliary gear is shifted from the low-speed side to the high-speed side, the sub-transmission is When the transmission is shifted to the lower speed side, the speed of the main transmission is shifted to the speed at which the auxiliary transmission was previously at the lower speed by the action of the speed adjusting means, and the auxiliary transmission remains at the set speed. It returns to a state where transmission can be performed at a higher speed.

[Effect] Even if a sub-shift to a higher speed is performed while the main transmission is at a higher speed than the set speed, the main transmission is shifted to the set speed and a shift shock occurs. It is difficult to come out and it can run lightly. For that reason,
When the sub-transmission is re-shifted to a lower speed, the main transmission automatically returns to the higher-speed gear position before the previous sub-transmission,
The traveling device can be driven at a relatively high speed to work efficiently.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a steering handle 3, which is self-propelled by a pair of left and right drivable front wheels 1, 1 and rear wheels 2, 2, steers the front wheel 1,
A transmission case 5 forming a rear part of a self-propelled body provided with a driving unit having a driving seat 4 and a driving cabin C
The agricultural tractor is provided with a lift arm 6 for connecting various working devices such as a rotary tilling device in a vertically movable manner and a power take-off shaft 7 for transmitting power to the connected working devices.

FIG. 2 shows a traveling transmission device for transmitting the rotational output of the engine 8 located at the prime mover at the front end of the self-propelled body to the front and rear wheels 1 and 2 to enable the self-propelled body to run. I have. That is, the rotational output of the engine 8 is introduced into the transmission case 5 and the two clutches 11,
The transmission output is transmitted to the forward / reverse switching device 10 including the first clutch 12 and the rotational output of the forward / reverse switching device 10 is transmitted to the six clutches 21 to 2.
6 is transmitted to the main transmission 20 having the
0 is transmitted to the auxiliary transmission 30 having one shift gear 30a, and the rotational output of the auxiliary transmission 30 is transmitted to the rear wheel differential mechanism 2a. , 2. In addition, the auxiliary transmission 30
Is transmitted to a front wheel transmission 33 via a rotation shaft 32, and the rotation output of the front wheel transmission 33 is transmitted to a front wheel differential mechanism 1a via a rotation shaft 34 to thereby transmit the differential mechanism 1a
To the left and right front wheels 1, 1. The clutch 35 shown in FIG. 2 is a working clutch, and transmits the rotational power transmitted from the engine 8 via the rotary shaft 36 penetrating the rotary cylinder shaft 14 to the power take-out shaft 7.

The forward / reverse switching device 10 includes the two clutches 11 and 12 and a reverse transmission shaft 13 that is gear-coupled to the output side of one clutch 12.
By turning on and off the switches 1 and 12, the state is switched between a forward transmission state, a reverse transmission state, and a neutral state. That is,
Each of the two clutches 11 and 12 is configured as a hydraulic clutch that switches on and off a wet friction type multi-plate clutch mechanism by hydraulic pistons 11a and 12a located inside the clutch body. Pressure oil is supplied to the hydraulic piston 11a of one of the forward clutches 11 to turn on the forward clutch 11 and supply of hydraulic oil to the hydraulic piston 12a of the other reverse clutch 12 is released to release the reverse clutch 12 When it is turned off, the forward power transmission state is set so that the rotational power from the engine 8 is transmitted from the forward clutch 11 to the rotary cylinder shaft 14 which is also used as the output shaft of the forward / reverse switching device 10 and the input shaft of the main transmission 20. Become. Hydraulic piston 11a of forward clutch 11
When the supply of pressurized oil to the reverse clutch 11 is released and the forward clutch 11 is turned off, the hydraulic oil is supplied to the hydraulic piston 12a of the reverse clutch 12 and the reverse clutch 12 is turned on, the rotational power from the engine 8 is reversed. The transmission is in a reverse transmission state so as to be transmitted from the clutch 12 to the rotary cylinder shaft 14 via the reverse transmission shaft 13. When both the forward clutch 11 and the reverse clutch 12 are turned off, the rotary cylinder shaft 1
4 to a neutral state so as to stop power transmission.
Thus, the forward / reverse switching device 10 is a traveling clutch that transmits the turning power from the engine 8 to the main transmission 20 and the auxiliary transmission 30 or disconnects the transmission.

The main transmission 20 is a first main transmission 20a including four clutches 21 to 24 of the six shift clutches 21 to 26 and the rotary cylinder shaft 14 as an input shaft. And the six clutches 2
The first main transmission 20a is connected in series to the first transmission 20a by being provided with the other two clutches 25 and 26 of the first transmission 26 and the output shaft 27 of the first main transmission 20a being an input shaft. This is constituted by the second main transmission 20b. Then, as shown in FIG.
The on / off operation of the gear 26 changes the speed in eight stages from a first speed to an eighth speed. ON shown in FIG. 5 indicates engagement of each clutch 21-26, and-indicates each clutch 21-26.
Indicates a cut. That is, each of the six clutches 21 to 26 is configured as a hydraulic clutch that switches on and off a wet friction type multi-plate clutch mechanism by hydraulic pistons 21a to 26a located inside the clutch body.
Of the four clutches 21 to 24 of the main speed device 20a, pressurized oil is supplied to the hydraulic piston 21a of the first speed clutch 21, and the first speed clutch 21 is turned on, so that the second main transmission device 20b When hydraulic oil is supplied to the hydraulic piston 25a of one of the two low-speed clutches 25 and 26 and the low-speed clutch 25 is turned on, the rotational power from the forward / reverse switching device 10 is transmitted to the first-speed clutch 21, The first speed is set so as to be transmitted to the auxiliary transmission 30 via the output gear 27, the transmission gear 28 rotatably supported by the rotating shaft 36, and the low-speed clutch 25. 4 of the first main transmission 20a
Pressure oil is supplied to the hydraulic piston 22a of the second-speed clutch 22 of the two clutches 21 to 24 to operate the second-speed clutch 22 to engage, and to engage the low-speed clutch 25 of the second main transmission 20b. When operated, the rotational power from the forward / reverse switching device 10 is transmitted to the second speed clutch 22, the output shaft 27,
The second speed is established so as to be transmitted to the subtransmission 30 via the transmission gear 28 and the low speed clutch 25. Of the four clutches 21 to 24 of the first main transmission device 20a, pressure oil is supplied to the hydraulic piston 23a of the third speed clutch 23, and the third speed clutch 23 is turned on to operate the second main transmission device 20.
When the low-speed clutch 25 is operated, the rotational power from the forward / reverse switching device 10 is transmitted to the auxiliary transmission 30 via the third-speed clutch 23, the output shaft 27, the transmission gear 28, and the low-speed clutch 25. It becomes the third speed. First
Of the four clutches 21 to 24 of the main transmission 20a, pressure oil is supplied to the hydraulic piston 24a of the fourth speed clutch 24 to turn on the fourth speed clutch 24, and the second main transmission 20b When the low speed clutch 25 is engaged, the rotational power from the forward / reverse switching device 10 is transmitted to the auxiliary transmission 30 via the fourth speed clutch 24, the output shaft 27, the transmission gear 28, and the low speed clutch 25. 4th gear. The first clutch 21 of the first main transmission 20a is turned on, and the two clutches 2 of the first subtransmission 20b are shifted.
When the high-speed clutch 26 is turned on by supplying hydraulic oil to the hydraulic piston 26a of the other high-speed clutch 26 of the first and second high-speed clutches 26, the rotational power from the forward / reverse switching device 10 is supplied to the first-speed clutch 21 and the output shaft. 27, the fifth speed is established so as to be transmitted to the auxiliary transmission 30 via the high speed clutch 26. When the second speed clutch 22 of the first main transmission 20a is turned on and the high speed clutch 26 of the second main transmission 20b is turned on, the turning power from the forward / reverse switching device 10 is turned on by the second speed.
The sixth speed is established so as to be transmitted to the auxiliary transmission 30 via the speed clutch 22, the output shaft 27, and the high speed clutch 26. First
When the third speed clutch 23 of the main transmission 20a is turned on and the high speed clutch 26 of the second main transmission 20b is turned on, the rotating power from the forward / reverse switching device 10 is turned to the third speed.
The seventh speed is established so as to be transmitted to the auxiliary transmission 30 via the speed clutch 23, the output shaft 27, and the high speed clutch 26. First
When the fourth speed clutch 24 of the main transmission 20a is turned on and the high speed clutch 26 of the second main transmission 20b is turned on, the rotational power from the forward / reverse switching device 10 is changed to the fourth speed.
The eighth speed is established so as to be transmitted to the auxiliary transmission 30 via the speed clutch 24, the output shaft 27, and the high speed clutch 26.

When all of the first to fourth speed clutches 21 to 24 are disengaged, the first main transmission 20a
Is in a neutral state to stop transmission to the second main transmission 20b. When both the low-speed clutch 25 and the high-speed clutch 26 are disengaged, the second main transmission 20b enters a neutral state so as to stop transmission to the auxiliary transmission 30.
By disengaging all of the first to fourth speed clutches 21 to 24, the low speed clutch 25, and the high speed clutch 26, the main transmission 20 is disconnected from the forward / reverse switching device 10 and the auxiliary transmission 30. Become neutral.

As shown in FIGS. 2 and 4, the auxiliary transmission 3
0 is the input gear 3 on the output shaft of the second main transmission 20b.
0b is connected in series to the second main transmission 20b by being connected so as to rotate integrally. Then, the shift gear 30a is slid to operate the input gear 30b.
And a gear 30c whose output shaft is rotatably supported, whereby the speed changes in two stages: a high speed state and a low speed state.

A hydraulic circuit for operating each of the clutches 11, 12, 21 to 26 is constructed as shown in FIG. That is, the control valve 41 of the forward clutch 11, the control valve 42 of the reverse clutch 12, the control valve 43 of the first speed clutch 21, the control valve 44 of the second speed clutch 22, the control valve 45 of the third speed clutch 23, the fourth Control valve 4 for speed clutch 24
6. Control valve 47 for low-speed clutch 25, high-speed clutch 26
Of the control valve 48 gradually increases the pressure of the forward clutch 11 and the reverse clutch 12 to the transmission clutch pressure by gradually supplying hydraulic oil to the control valves 41 and 42 of the forward clutch 11 and the reverse clutch 12. It is connected to one hydraulic pump P via an oil supply passage 50 having a proportional control valve 49. An electromagnetically operated valve 41a is connected to the operating portion of the control valve 41 of the forward clutch 11 via a pilot circuit, and an electromagnetically operated valve 42a is connected to the operating portion of the control valve 42 of the reverse clutch 12 via a pilot circuit. Each of the solenoid operated valves 41a and 42a is urged by a spring toward the oil drainage side. By supplying an operating current to the solenoid operated valve 41a and switching the operation to the oil supply side, the control valve 41 is drained for pilot oil pressure. The clutch is switched to the oil supply side against the self-restoring force to the oil side, and the forward clutch 11 is engaged. By supplying an operating current to the solenoid operated valve 42a to switch to the refueling side, the control valve 42 switches to the refueling side against the self-restoring force to the draining side due to the pilot oil pressure, and the reverse clutch 1
2 enters. By operating both the solenoid operated valves 41a and 42a on the oil drain side, both control valves 41 and 42 are on the oil drain side, and both the forward clutch 11 and the reverse clutch 12 are disengaged.
The forward / reverse switching device 10 enters the neutral state. An electromagnetically operated valve 43a is connected via a pilot circuit to an operation portion of the control valve 43 of the first speed clutch 21 and a control valve 44 of the second speed clutch 22
Of the solenoid operated valve 44a via a pilot circuit
And an electromagnetically operated valve 45a via a pilot circuit for an operation section of a control valve 45 of the third speed clutch 23 and an electromagnetically operated valve 46a via a pilot circuit for an operation section of a control valve 46 of the fourth speed clutch 24, respectively. Connected. Each of the solenoid operated valves 43a to 46a is urged by a spring toward the oil drainage side. By supplying an operating current to the solenoid operated valve 43a and switching the operation to the oil supply side, the control valve 43 is drained for pilot oil pressure. The first speed clutch 21 is engaged by switching to the oil supply side against the self-restoring force to the oil side. By supplying an operating current to the solenoid operated valve 44a to switch to the oil supply side, the control valve 44 switches to the oil supply side against the self-restoring force to the oil discharge side due to the pilot oil pressure, and the second speed The clutch 22 is engaged. By supplying an operating current to the solenoid operated valve 45a to switch to the refueling side, the control valve 45 switches to the refueling side against the self-restoring force to the draining side due to the pilot oil pressure, and the third speed is set. The clutch 23 is engaged. By supplying an operating current to the solenoid operated valve 46a to switch to the refueling side, the control valve 46 is switched to the refueling side against the self-restoring force to the draining side due to the pilot oil pressure, and the fourth speed is set. The clutch 24 is engaged.

Both the control valve 47 of the low-speed clutch 25 and the control valve 48 of the high-speed clutch 26 are configured as electromagnetic proportional control valves, and when the clutches 25 and 26 are operated to the on-going side, the transmission pressure is gradually increased to a predetermined transmission clutch pressure. It can be controlled so as to increase the pressure. That is, the control valves 47 and 48 are operated to the clutch engagement side by supplying an operation current to the electromagnetic solenoids of the control valves 47 and 48, but the control is performed by adjusting the current value and supply time of the operation current. Valve 4
The opening degree and opening time of the clutches 25 and 2 change, and the clutches 25 and 2 open.
The clutch pressure of No. 6 can be adjusted.

An on-off valve 51 is connected to a pilot circuit of the forward clutch 11 and the reverse clutch 12. The on-off valve 51 is switched by a clutch pedal 52 located in the operating section, and the forward clutch 11 is also switched to the reverse clutch 1.
The reference numeral 2 also indicates that the electromagnetically operated valves 41a and 42a are turned on prior to the electromagnetically operated valves 41a and 42a, and that the forward clutch 11 and the reverse clutch 12 can be operated by the electromagnetically operated valves 41a and 42a. That is, the forward / reverse switching device 10 can be operated to the neutral state by the clutch pedal 52. The clutch 53 of the hydraulic clutches 53 to 56 shown in FIG. 3 switches the front wheel differential mechanism 1a between a differential lock state and a differential lock release state, and the clutch 54 controls the rear wheel differential mechanism 2a. The clutch is switched between a differential lock state and a differential lock release state, and the clutches 55 and 56 switch the front wheel transmission 33 between a standard state and a speed increasing state. That is, when the clutch 55 is turned on, the front wheel transmission 33 is set to the standard state, and the front wheels are driven such that the average peripheral speeds of the left and right front wheels 1 and 1 and the left and right rear wheels 2 and 2 are substantially the same. When the clutch 56 is turned on, the front wheel transmission 33 is in an increased speed state, and the front wheels such that the average peripheral speed of the left and right front wheels 1, 1 is about twice the average peripheral speed of the left and right rear wheels 2, 2. Drive.

An auxiliary shift lever 60 provided on the side of the driver's seat 4 of the operating section as shown in FIG. 4, a shift up switch 61, a shift down switch 62 provided on the side of the grip portion of the auxiliary shift lever 60, and an auxiliary shift A detection switch 74, a forward / reverse lever 63 provided near the steering handle 3 of the driving unit as shown in FIG. 4, and a display device 6 provided on the driving panel of the driving unit.
4, the electromagnetic operating valves 41a-41
The traveling speed change is performed by operating 46a and 47, 48, the electromagnetic proportional control valve 49, and the shift gear 30a. The speed change operation device is configured as follows.

The shift-up switch 61 and the shift-down switch 62 are linked to a control device 69. The shift-up switch 61 outputs a shift-up command for one shift-up to the control device 69 by an electric signal each time the button is pressed, and the shift-down switch 62 switches one time each time the button is pressed. A downshift command is output to the controller 69 as an electric signal.

As shown in FIG. 4, the auxiliary transmission lever 60 is
Attached to the self-propelled body so as to swing in the front-rear direction of the self-propelled body around the axis 60a of the mounting boss portion,
A lock release button 65 provided on the side of the grip portion of the sub-transmission lever 60 is pressed to operate, and a lock pin 66 protruding from between the grip portion of the auxiliary transmission lever 60 and the mounting boss portion is fixed to the body side. The swinging operation can be performed by being removed from the positioning tool 67. An arm portion extending from the mounting boss portion of the sub-transmission lever 60 so as to be rotatable integrally therewith is linked to a shift fork support shaft 30d of the sub-transmission device 30 by a mechanical linkage mechanism 68 including a rod and a swing link. When the sub-transmission lever 60 is swung about the shaft center 60a, the shift fork support shaft 30d is slid by the lever operation force, and the shift fork support shaft 30d is slidably supported by the shift fork support shaft 30d. A shift fork 30e slides on a shift gear 30a to engage the input gear 30b, a high-speed position for engaging the gear 30c, and a gear 30b.
Is switched to a neutral position that does not mesh with any one of 30c and 30c.

The sub-shift detection switch 74 is configured to be turned on when the lock release button 65 is pressed. That is, in order to shift the speed of the subtransmission 30, the lock release button 65 is depressed by pushing the lock release button 65 and unlocking it so that the subtransmission lever 60 can be operated. When this is detected, it is detected that the speed change operation of the subtransmission 30 has been performed, and this detection result is output to the control device 69 as an electric signal.

The rotation boss of the potentiometer 70 is linked to the mounting boss of the sub-shift lever 60, and the potentiometer 70 is operated in any one of the high-speed position H, the neutral position N, and the low-speed position L. Is detected, and the detection result is output to the control device 69 as an electric signal.

A forward / reverse detection switch 71 is provided at the base of the forward / reverse lever 63.
1 detects whether the forward / reverse lever 63 has been operated to any of the forward position F, the neutral position N, and the reverse position R,
The detection result is output to the control device 69 as an electric signal.

The display device 64 includes a shift display portion 64a, a forward lamp 64b, a reverse lamp 64c, and a neutral lamp 64d. When the main transmission 20 is in any one of the first to eighth speeds, the shift display unit 64a lights up the Arabic numeral corresponding to the speed. For example, when the main transmission 20 is in the eighth speed, the number 8 is turned on. That is, the number is used as an example of the index of the gear position display, and the main transmission 20
It indicates which of the eighth speeds the speed is set. The forward lamp 64b is displayed by lighting when the forward / reverse switching device 10 is in the forward state. The reverse lamp 64c is displayed by lighting when the forward / reverse switching device 10 is in the reverse state. The neutral lamp 64d is
When at least one of the forward / reverse switching device 10 and the subtransmission 30 is in the neutral state, it is displayed by lighting.

The control device 69 includes the solenoid operated valves 41a to 41a-4
6a, the control valves 47 and 48, the electromagnetic proportional control valve 49, and the pressures provided to each of the clutches 11, 12, 21 to 26 to detect whether or not they are engaged based on pressure detection. Sensor 73, display device 64, buzzer 7
2, a shift control means 69a comprising a microcomputer linked to
Are operated based on shift commands from a shift-up switch 61 and a shift-down switch 62.
a and the control valves 47, 48 to operate the clutches 21-26.
, The main transmission 20 is shifted.

That is, when the operation button of the shift-up switch 61 is pressed, the switch 61 outputs a shift-up shift command only once, and the shift control means 69.
a is set to 1 based on the speed change command from the switch 61 and the speed at which the main transmission 20 is at this time.
The shift speed on the high-speed side by the stage is set as the shift target speed, and the first to fourth speed clutches 21 to 24, the low speed clutch 25,
Driving the pistons 21a to 26a of the predetermined clutch for displaying the shift target stage of the high-speed clutch 26, and operating the clutch to engage. As a result, the main transmission 20 is shifted from the first gear to the eighth gear by one gear before the gear change operation.
The shift speed changes to the high speed side by the speed. When the operation button of the shift down switch 62 is pressed and operated,
The switch 62 outputs a downshift command only once, and the shift control means 69a determines the shift speed based on the shift command from the switch 62 and the speed at which the main transmission 20 is operating at this time. The shift stage on the low speed side by one stage is set as the shift target stage, and the first to fourth speed clutches 21 to 21 are set.
24, a low-speed clutch 25, and a high-speed clutch 26, and a piston 2
1a to 26a are driven to operate the clutch. As a result, the gear position of the main transmission 20 changes to one of the first to eighth speeds, which is one step lower than the speed before the speed change operation.

When the speed change of the subtransmission 30 is performed, the control device 69 controls the potentiometer 70 and the pressure sensor 73.
6 and 7 based on the information from. That is, as shown in steps # 1 and # 2, the sub-transmission 30 is shifted to the high-speed side by detecting that the sub-transmission lever 60 has been operated to the high-speed position H based on the information from the potentiometer 70. At this time, each of the pressure sensors 73... Determines which of the first to eighth speeds the main transmission 20 is in.
From the detected shift speed X
H to the first storage means 69 which is a memory unit of the control device 69
b. Next, as shown in steps # 3 and # 4, the sub-transmission 30 is switched to the low-speed side by detecting that the sub-transmission lever 60 has been switched to the low-speed position L based on information from the potentiometer 70. When the main transmission 20 is detected at this time, the gear position of the first to eighth speeds is detected based on information from each of the pressure sensors 73.
The detected shift speed XL is stored in the second storage means 69c which is a memory unit of the control device 69. Next, # 5 ~ #
As shown in step 7, by detecting based on information from the potentiometer 70 that the sub-transmission lever 60 has been switched to the high-speed position H, the sub-transmission 3
When it is detected that 0 has been switched to the high speed side, it is determined whether or not the stored gear XH by the first storage means 69b is higher than or equal to the fourth speed, and it is determined that the stored gear XH is higher than or equal to the fourth speed. In this case, an operation current is supplied to the operation valve 45a and the control valve 47 so that the main transmission 20 is set to the third speed. That is, the main transmission 20 is switched to the third speed which is lower than the speed XH stored by the first storage means 69b. If it is determined in step # 6 that the shift speed XH stored by the first storage means XH is lower than or equal to the third speed, the process proceeds to step # 8.
As shown in the step, an operation current is supplied to the operation valves 43a, 44a, 45a and the control valve 47 so that the main transmission 20 has a gear position equal to the gear position XH stored by the first storage means XH. That is, the main transmission 20 is maintained at the gear position when the sub transmission 30 was previously on the high speed side.
Thereafter, as shown in steps # 9 and # 10, the sub-transmission 30 is switched to the low-speed side by detecting that the sub-transmission lever 60 has been switched to the low-speed position L based on information from the potentiometer 70. When it is detected that the transmission has been performed, the main transmission device 20 supplies an operation current to the operation valves 43a to 46a and the control valves 47 and 48 so that the speed is set to a speed equal to the speed XL stored by the second storage means 69c. That is, the speed of the main transmission 20 is shifted to the speed at which the auxiliary transmission 30 was previously on the low speed side. After this,
As shown in step # 11, the first and second storage means 6
9b and 69c are erased, and then the sub-transmission 30
Is reset so that the gear position of the main transmission device 20 when the transmission is switched to the high-speed side or when the auxiliary transmission device 30 is switched from the high-speed side to the low-speed side can be stored.

Thus, the # 1 to # 8 steps constitute the restraining means 69d. The restraining means 69d shifts the speed of the auxiliary transmission 30 from the high-speed side to the low-speed side and then to the high-speed side as shown in FIG. By operating the main transmission 20 based on the gear position of the main transmission 20 when the sub-transmission 30 was previously on the high speed side, the sub-transmission 3
0 when the speed is shifted from the low speed side to the high speed side
Checking is performed. That is, the main transmission 20 is automatically operated prior to the shift control means 69a so as not to be higher than the third speed set in advance as the set shift speed. Steps # 3 to # 10 constitute the speed control means 69e,
As shown in FIG. 8, the speed control means 69e
When the transmission is shifted from the low speed side to the high speed side and then shifted to the low speed side, the main transmission device 20 is given priority over the shift control means 69a to the gear position when the sub transmission device 30 was previously at the low speed side. And operate automatically. That is, 1H shown in FIG.
8H indicate the shift speeds of the main transmission 20 when the auxiliary transmission 30 is on the high speed side. For example, 6H is the main transmission 2 when the auxiliary transmission 30 is on the high speed side.
0 indicates the sixth speed, and 4H indicates the fourth speed of the main transmission 20 when the auxiliary transmission 30 is on the high speed side. 1L to 8L indicate the shift speeds of the main transmission 20 when the auxiliary transmission 30 is on the low speed side. For example, 8
L indicates the eighth speed of the main transmission 20 when the auxiliary transmission 30 is on the low speed side, and 2L indicates the second speed of the main transmission 20 when the auxiliary transmission 30 is on the low speed side. Indicates speed. For example, as shown by a two-dot chain line in FIG. 8, when the sub-transmission 30 is shifted from the high speed side to the low-speed side and then shifted to the high-speed side, when the sub-transmission 30 was previously at the high-speed side. If the shift speed of the main transmission 20 is the eighth speed, the traction control means 69d shifts the speed of the main transmission 20 to the third speed prior to the shift control means 69a. Thereafter, when the speed of the auxiliary transmission 30 is shifted to the low speed side, the speed adjusting means 69e operates the main transmission 2
0 is operated to the eighth speed, which is the gear position of the main transmission 20 when the subtransmission 30 was previously on the low speed side. Further, as shown by the solid line, when the sub-transmission 30 is shifted from the high-speed side to the low-speed side and then shifted to the high-speed side, the main transmission 2 when the sub-transmission 30 was previously at the high-speed side.
If the 0 shift speed is the fourth speed, the traction control means 69d shifts the speed of the main transmission 20 to the third speed prior to the shift control means 69a. Thereafter, when the sub-transmission 30 is shifted to the low speed side, the speed adjusting means 69e changes the main transmission 20 to the main transmission 20 when the sub-transmission 30 was previously at the low speed side.
Is operated to the fourth speed, which is the shift speed of the second gear. Further, as shown by the broken line, when the sub-transmission 30 is shifted from the high-speed side to the low-speed side and then shifted to the high-speed side, the main transmission 20 when the sub-transmission 30 was previously at the high-speed side is shown. If the shift speed of the second gear is the second speed, the restraint means 69d shifts the speed of the main transmission device 20 to the second speed prior to the shift control means 69a. Thereafter, when the sub-transmission 30 is shifted to the low speed side, the speed adjusting means 69e changes the main transmission 20 to the gear position of the main transmission 20 when the sub-transmission 30 was previously at the low speed side. Operate to a certain second speed.

When the shift operation of the subtransmission 30 is performed,
The sub-shift control means comprising a shift program of the control device 69 automatically operates the forward / reverse switching device 10 based on information from the sub-shift detection switch 74 and the potentiometer 70. That is, the forward / reverse switching device 10 is in the neutral state during the shift operation in which the shift gear 30a is switched, and after the shift gear 30a is switched to the forward position or the reverse position, the forward / backward switching device 10 is moved forward or backward. Operate to be in the transmission state.

The control device 69 is provided with forward / reverse control means comprising a shift program. When the forward / reverse lever 63 is operated, the forward / backward control means is operated based on information from the detection switch 71 and the pressure sensor 73. It works as follows.
That is, when the forward / reverse lever 63 is at the forward position F, an operating current is supplied to the solenoid operated valve 41a to switch the forward / reverse switching device 10 to the forward state, and the forward lamp 64a of the display device 64 is turned on. When the forward / reverse lever 63 is at the reverse position R, an operation current is supplied to the solenoid-operated valve 42a to switch the forward / reverse switching device 10 to the reverse state, and the reverse lamp 64c of the display device 64 is turned on and the buzzer 72 is intermittently turned on. Activate to trigger alarm. When the forward / reverse lever 63 reaches the neutral position N, the solenoid operated valve 41
and the forward / reverse switching device 10 is switched to the neutral state, and the display device 64 is turned off.
The neutral lamp 64d is turned on.

That is, in performing the running operation of the aircraft,
Shift up switch 61 and shift down switch 62
, The sub-shift lever 60 performs the sub-shift, and the forward-reverse lever 63 switches between forward and backward.

That is, when the shift-up switch 61 is pressed, the switch 61 outputs a shift-up command for shifting up only once, and based on the shift command, the shift control means 69a controls the first to fourth speed clutches 21 to 21. By operating the low speed clutch 24, the low speed clutch 25, and the high speed clutch 26 to the speed increasing side, the main transmission device 20 shifts by one step to the higher speed side from the speed before the speed change operation among the first to eighth speeds. Become a step. When the downshift switch 62 is pressed, the switch 62 outputs a downshift command only once, and based on the downshift command, the shift control means 69a causes the first to fourth speed clutches 21 to 24 to operate. ,
By operating the low-speed clutch 25 and the high-speed clutch 26 to the deceleration side, the main transmission 20 is shifted to a speed lower by one step than the speed before the speed change operation among the first to eighth speeds. .

The auxiliary transmission lever 60 is
The rocking operation is performed while the lock operation of the lock pin 66 is released by pushing the button 5. When the sub-transmission lever 60 is operated to the high-speed position H, the shift gear 30a is brought to the high-speed position by the lever operation force, and the sub-transmission 30 outputs the turning power from the main transmission 20 at the same rotation speed. It becomes a high-speed state. Sub transmission lever 6
When 0 is moved to the low-speed position L, the shift gear 30a is brought to the low-speed position by this lever operating force, and the sub-transmission 30 is brought into a low-speed state such that the rotational power from the main transmission 20 is output at a reduced speed.

In this subtransmission, when the subtransmission device 30 is switched from the low speed side to the high speed side, the main transmission device 20 is operated by the action of the restraint means 69d so as not to be higher than the third speed side. That is, irrespective of whether the main transmission 30 has been shifted when the subtransmission 30 is first on the low speed side, the main transmission 20 when the subtransmission 30 was previously on the high speed side is not changed. If the shift speed is the fourth speed, the shift speed is operated to the third speed, and the shift speed of the main transmission 20 when the auxiliary transmission 30 was previously on the high speed side was lower than the third speed. In such a case, the gear is operated at that speed. After that, when the sub-transmission 30 is switched to the low-speed side, the speed of the main transmission 30 is not changed when the sub-transmission 30 is first at the high-speed side by the operation of the speed adjusting means 69e. Regardless, the main transmission 20 is operated to the gear position of the main transmission 20 when the sub transmission 30 was previously on the low speed side.

When the forward / reverse lever 63 is swung in the longitudinal direction of the fuselage to the forward position F, the shift control means 69a transmits the forward clutch 1 based on the information from the detection switch 71.
The first hydraulic piston 11a is driven to operate the clutch 11 in engagement. As a result, the forward / reverse switching device 10 is set in the forward traveling state so as to transmit the turning power from the engine 8 to the main transmission 20 as forward driving force. Forward / reverse lever 6
When the third gear 3 is moved to the reverse position R, the shift control means formed by the control program of the control device 69 drives the hydraulic piston 12a of the reverse clutch 12 based on the information from the detection switch 71 to turn on the clutch 12. As a result, the forward / reverse switching device 10 enters a reverse state in which the rotational power from the engine 8 is transmitted to the main transmission 20 as reverse driving force.

[Another Embodiment] Instead of the shift-up switch 61 and the shift-down switch 62, a main shift comprising a shift lever and a shift switch for detecting the operating position of the shift lever and outputting the detection result to the shift control means. The present invention can be applied to a case where the present invention is implemented by employing operation means. Therefore, these switches 61 and 62 and the shift lever are collectively referred to as a main shift operating tool.

The present invention can be applied to a case where a speed change switch is employed in place of the speed change lever 60, and the speed change switch and the speed change switch are collectively referred to as a speed change operation tool.

[Brief description of the drawings]

Fig. 1 Side view of the whole agricultural tractor

FIG. 2 is a schematic view of a traveling transmission device.

FIG. 3 is a hydraulic circuit diagram of a shift control.

FIG. 4 is a block diagram of shift control;

FIG. 5 is an explanatory diagram of a shift speed of the main transmission.

FIG. 6 is a flowchart of shift control.

FIG. 7 is a flowchart of shift control.

FIG. 8 is an explanatory diagram of a shift operation by a check means and a speed control means.

[Explanation of symbols]

 REFERENCE SIGNS LIST 20 main transmission device 30 auxiliary transmission device 60 auxiliary transmission operation tool 61, 62 main transmission operation tool 69 a transmission control means 69 d restraint means 69 e speed control means

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akio Inamori 64 Ishizukita-cho, Sakai-shi, Osaka F-term in Kubota Sakai Works Co., Ltd. (Reference) 3D040 AA38 AB04 AC33 AC34 AC56 AC65 AE12 AE14 AE17 AF07 AF16 3J028 EA21 EB09 EB15 EB18 EB21 EB23 EB25 EB28 EB33 EB62 FA55 GA14 HC15 3J067 AA02 AB11 AC04 AC51 AC53 BA18 BA28 CA32 CA34 DB12 DB15 DB34 FB01 GA03 GA14

Claims (3)

[Claims] 1. A traveling transmission device in which a main transmission capable of shifting to a plurality of speeds and an auxiliary transmission capable of shifting to a high speed and a low speed are connected in series, and a shift command from a main speed change tool is provided. A speed change control device for shifting the speed of the main transmission on the basis of the above, and a speed change operation device for traveling of a work vehicle including a sub speed change operation tool for performing a speed change operation of the auxiliary speed change device, wherein the auxiliary speed change device is a low speed side. A shift operation device for traveling of a work vehicle, which is provided with a check means for automatically operating the main transmission device prior to the shift control device so as to prevent the main transmission device from being shifted to a higher speed side than a set shift speed when the speed is shifted to a higher speed side. . 2. When the auxiliary transmission is shifted from a high speed side to a low speed side and then shifted to a high speed side, the shift stage of the main transmission when the sub transmission was previously shifted to the high speed side is the same as that of the main transmission. When the gear is higher than the set gear, the braking means shifts the main transmission to the set gear prior to the shift control, and the sub-gear shifts from the high gear to the low gear. When the speed is shifted to a higher speed after the speed is changed, and the speed of the main transmission is lower than the set speed when the sub-transmission is previously at the higher speed,
2. The traveling speed change operation device for a work vehicle according to claim 1, wherein the check means is configured to perform a speed change operation of the main transmission at a gear position prior to the speed change control means. 3. When the sub-transmission is shifted from the low speed side to the high-speed side and then shifted to the low-speed side, the main transmission shifts to the gear position of the main transmission when the sub-transmission was previously at the low-speed side. 3. The shift operating device for traveling of a work vehicle according to claim 1, further comprising a speed adjusting unit that shifts a device by giving priority to the shift control unit.