JP2003211986A - Running gear shift device for work vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a running gear shift device for a work vehicle, capable of changing speed to desired one for backing only by operation of a backing gear shift lever. <P>SOLUTION: This work vehicle is provided with gear shift mechanisms 4K, 3K capable of shifting running speed of a machine body to a plurality of speeds by operation of levers 4L, 3L and an advance and backing gear shift mechanism 7 switching advance and backing by operation of an advance and backing change-over lever 7L to advance or back the machine body by operating the advance and backing change-over lever 7L at running speed selected by operation of the gear shift levers 4L, 3L. A backing gear shift mechanism 5K capable of selecting backing speed is also provided in the advance and backing gear shift mechanism 7 to operate the backing gear shift mechanism 5K by the backing gear shift lever 5L in order to set to desired backing speed in advance. <P>COPYRIGHT: (C)2003,JPO

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 Conventionally, a tractor as a work vehicle has been set by a main transmission mechanism that selects a traveling speed of a vehicle body by a lever operation of a main transmission lever and a main transmission mechanism by operating a lever of an auxiliary transmission lever. Auxiliary speed change mechanism that further changes the traveling speed and shuttle lever (forward / reverse switching lever)
The transmission is equipped with a forward / reverse speed change mechanism that switches between forward and reverse by operating the lever, and the shuttle lever is operated in the forward / backward direction at the traveling speed selected by operating the main speed change lever and the auxiliary speed change lever. Is moving forward or backward.

[0003]

In a tractor equipped with such a traveling transmission, the traveling speed during forward or reverse travel is determined by the speed ratio selected by operating the main transmission lever and the auxiliary transmission lever. Depending on the type of work, the work cannot be performed efficiently unless the shuttle lever and the auxiliary shift lever or the main shift lever are operated at the same time, and the lever operation is troublesome.

[0004] In addition, if the reverse speed is too fast,
Since it becomes difficult to control, it is necessary to adjust the speed by operating the throttle lever and auxiliary shift lever at the same time when moving backward. Also, when moving forward, the shuttle lever is turned back to the forward side in order to fully perform the work of the tractor and the work equipment attached to the tractor.
Lever operation to return the other levers to the original high speed side was necessary.

On the other hand, when a skilled worker performs loader work, etc., in order to improve work efficiency, the reverse speed is made as fast as possible within a range that does not hinder driving, and the reverse time is shortened. And so on.

In such work, the speed ratio between forward and reverse is fixed by the operation of the main speed change lever and the auxiliary speed change lever. Depending on the situation, there was a problem that the function of the forward / reverse speed change mechanism was not fully exerted.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a traveling speed change device for a work vehicle in which only a reverse speed can be changed to a desired speed by operating a reverse speed change lever. It is a thing.

[0008]

In order to achieve the above object, the present invention as set forth in claim 1, is a transmission mechanism 4 for shifting the traveling speed of the machine body to a plurality of stages by operating the levers 4L, 3L.
K and 3K, and a forward / reverse speed change mechanism 7 that switches between forward and backward movements by operating the forward / backward movement switching lever 7L.
At the traveling speed selected by operating the shift levers 4L, 3L, in the working vehicle for operating the forward / backward switching lever 7L to move the vehicle forward or backward, select the reverse speed for the forward / backward speed change mechanism 7. It is characterized in that a reverse gear mechanism 5K capable of being installed is provided side by side and the reverse gear mechanism 5K is operated by the reverse gear lever 5L to set a desired reverse speed in advance.

According to the second aspect of the present invention, the forward / reverse switching lever 7L is provided with a lever restricting portion 63, and when the speed change levers 4L, 3L are tilted toward the high speed side, the lever restricting portion 63 is operated. The forward / reverse switching lever 7L is prevented from being operated backward.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a transmission case of a tractor (work vehicle) not shown, which is rotated in the transmission case 1 from an output shaft of an engine 1a via a main clutch 1b and a reduction gear portion 1c. The input shaft 2 is provided horizontally in the front-back direction of the machine body. A PTO speed change shaft 2a is mounted on the rear end of the input shaft 2 so as to be aligned with the input shaft 2. The rotation speed of the PTO speed change shaft 2a is changed by a PTO speed change lever (not shown).

The various transmission shafts driven by the input shaft 2, that is, the auxiliary transmission shaft 3, the main transmission shaft 4, the transmission idler shaft 4a, the back transmission shaft 5, the back idler shaft 5a, and the final shaft 2e are input. It is axially supported parallel to the axis 2. The final shaft 2e drives a differential gear device 2d having a brake device 2c corresponding to the left and right rear wheels 2b. Further, power is transmitted from the final shaft 2e to the front wheel transmission shaft 2g via the clutch gear mechanism 2f. In addition, the auxiliary transmission shaft 3 and the main transmission shaft 4
Are connected to each other via a joint portion 8.

Each of these shafts is provided with various gear and clutch mechanisms which will be described later, and operates a main gear shift lever 4L, an auxiliary gear shift lever 3L, and a reverse gear shift lever 5L, which are installed in a control unit (not shown). As a result, it is possible to select the shift range for forward and reverse over a plurality of gears. Further, by tilting the forward / reverse switching lever 7L in the forward / backward direction, the forward speed and the reverse speed can be selectively selected. Furthermore, as shown in FIG.
The forward / reverse switching lever 7L is operated by the reverse high speed restricting mechanism 6 to restrict the lever operation to the reverse speed change side.

As shown in FIG. 2, the speed change idler shaft 4a is constantly rotated by the input gear 24 on the rear end side of the input shaft 2, and four gears 4c provided on the speed change idler shaft 4a,
4 shift gears 4h, which are constantly meshed with 4d, 4e, 4f,
4i, 4j, 4k are rotatably supported on the main transmission shaft 4 and are provided on the main transmission shaft 4 in a synchromesh system.
By individually moving the clutch parts 40 and 41 in the front-rear direction by tilting the main transmission lever 4L,
The shifting gears 4h, 4i, 4j, 4k are selectively engaged with the four gears 4c, 4d, 4e, 4f of the shifting idler shaft 4a to form a main shifting mechanism 4K capable of shifting in four stages. I am trying.

Further, the sub-transmission shaft 3 is provided with a synchromesh type clutch portion 30 which can be operated by a forward / reverse switching lever 7L (see FIG. 3), and a high speed gear 31 and a middle gear are provided in front of the clutch portion 30. A gear group 35 in which the high speed gear 32 and the intermediate gear 33 are integrated is pivotally supported, and further, a reverse transmission gear 50 is pivotally supported on the rear side thereof, and the clutch portion 30 is connected to the forward / reverse switching lever 7L ( The auxiliary transmission shaft 3 is moved forward and backward by a tilting operation (see FIG. 3), thereby forming a forward-reverse transmission mechanism 7 capable of arbitrarily selecting the forward and reverse shifts.

Further, the back transmission shaft 5 is provided with a transmission gear 51 that meshes with the high speed gear 31 of the forward / reverse transmission mechanism 7, and a reverse transmission gear 52 composed of a high speed gear 56 and a low speed gear 54 is slidably provided. Further, when the reverse gear shift gear 52 is moved back and forth by operating the reverse gear shift lever 5L, the reverse idle gear 53 that selectively meshes with either one of the high speed gear 56 and the low speed gear 54 of the reverse gear shift 52 is moved. A reverse transmission mechanism 5K is configured by allowing the back idler shaft 5a to freely rotate.

The rotational speeds changed by the main speed change mechanism 4K having such a structure are further transmitted to the high speed gear 31 in a two-step high and low state, so that the reverse speed is changed to two.
It is possible to shift gears.

The final shaft 2e includes a sub-transmission gear 20 capable of meshing with a high speed gear 31 moved by a lever operation of a sub-transmission lever 3L, and a sub-transmission gear 21 capable of meshing with a middle speed gear 32. A counter gear 22 is provided slidably, and a counter gear 22 that meshes with the above-described intermediate gear 33 and a counter gear 23 of the input shaft 2 to be described later is supported by the idle shaft.
A transmission gear 25 that transmits power to the clutch gear mechanism 2f of the front wheel transmission shaft 2g is provided on the rear side.

Further, the input shaft 2 has an ultra-low speed gear 26 which can mesh with the counter gear 23 and the auxiliary transmission gear 21.
And a low speed gear 27 that can mesh with the high speed side auxiliary transmission gear 20.
And an idle shaft, and the clutch gear mechanism 2f
The transmission gear 25 'of FIG.

Further, when the sub transmission gear 20 is engaged with the high speed gear 31 by the sub transmission lever 3L, the sub transmission is performed at high speed, and the sub transmission gear 21 on the low speed side of the final shaft 2e is moved by the sub transmission lever 3L. When meshed with the middle speed gear 32, the rotation selected by the main transmission mechanism 4K and the reverse transmission mechanism 5K is transmitted to the differential gear device 2d and the transmission gear 25 via the final shaft 2e, so that the rear wheel 2b and the front wheel are connected. When the auxiliary transmission gear is changed to the middle speed and the auxiliary transmission gear 20 on the high speed side is meshed with the low speed gear 27, the rotation by the main transmission mechanism 4K and the reverse transmission mechanism 5K is transmitted through the counter gear 22 and the counter gear 23 to the final shaft 2e. A sub-transmission mechanism 3 capable of sub-shifting the rear wheels 2b and the front wheels to the low speed side.
Make up K.

When the auxiliary transmission gear 21 on the low speed side is brought into mesh with the ultra-low speed gear 26 by an arbitrary operating means such as the auxiliary transmission lever 3L, the final shaft 2e is further decelerated to an ultra-low speed to make the vehicle run at an ultra-low speed. Is configured as follows.

On the other hand, the main gearshift lever 4L, the sub gearshift lever 3L, and the reverse gear shift lever 5L are respectively provided on the base side thereof.
The detection sensors 4S, 3S, which detect the tilting operation to the high speed side,
5S is provided. These sensors 4S, 3S, 5S
4, constitutes a check circuit 65 of the reverse high speed regulation mechanism 6 (see FIG. 3), and is connected to a detection determination section 61 for actuating the solenoid 60.

As shown in FIG. 4, the forward / reverse transmission mechanism 7 has a forward / reverse switching lever 7L for operating the clutch portion 30 of the forward / reverse transmission mechanism 7 and a crank-shaped lever guide groove 62.
And the lever guide groove 6
A neutral position 64 is installed in the center of the gear 2, and when the forward / reverse switching lever 7L is operated forward, it is transmitted to the gear group 35 through the clutch unit 30 to shift gears when moving forward, and when the lever is moved backward, the clutch unit 30 is moved backward. The transmission gear 50 is meshed with the transmission gear 50 to shift gears in the reverse direction.

The neutral position 64 of the lever guide groove 62
The backward high speed regulation mechanism 6 is configured by providing a pin-shaped lever regulation portion 63 that can be advanced and retracted by turning the solenoid 60 on and off on the rear side, and the main shift lever 4L.
When the reverse shift lever 5L is shifted to the high speed side and the reverse shift lever 5L is shifted to the high speed side, the detection sensors 3S, 4S, 5S provided at the bases of the levers are all turned ON, The detection / judgment unit 61 is operated and the solenoid 61 is turned on
N, the pin-shaped lever regulation portion 63 is projected into the lever guide groove 62 to regulate the movement of the forward / reverse movement switching lever 7L to the backward movement side, thereby restraining the backward movement at high speed.

Further, the check circuit 65 is provided with a main switch 6S, which is turned off.
In this case, the pin-shaped lever restricting portion 63 is retracted from the lever guide groove 62 so that the reverse movement can be performed freely by the forward / reverse switching lever 7L even if the reverse speed change lever 5L is on the high speed side. It will be possible.

The tractor equipped with the traveling transmission having the above-mentioned structure, when performing work such as tilling and scraping with the main switch 6S of the restraint circuit 65 turned on, the operator is required to know the condition of the field and the level of proficiency. By operating the reverse gear shift lever 5L according to the working condition of No. 5, the reverse shift mechanism 5K is selectively shifted to the high speed or low speed side.

The main shift lever 4L and the sub shift lever 3L selectively shift the working speed adapted to the working condition prior to or after the reverse shift operation, and fully shift the throttle lever of the engine 1a. Work is performed with the throttle held.

In such a work, the machine body moves forward at a speed selected by the combination of the main transmission mechanism 4K and the auxiliary transmission mechanism 3K. However, when moving backward, the reverse speed is previously set by the reverse transmission lever 5L. , And reverses at high speed or low speed at the selected speed, so that it is possible to perform the reverse movement that is adapted to the operator and the working conditions.

In particular, when performing rotary tillage work with this tractor, if the reverse speed change lever 5L is previously operated to the low speed side and then the forward / reverse switch lever 7L is operated to the reverse speed side, the reverse speed work can be performed slowly. Therefore, work can be performed safely.

On the contrary, when performing the loader work, if the forward / reverse shift lever 5L is previously operated to the high speed side and then the forward / reverse switching lever 7L is operated to the reverse speed, the reverse high speed is achieved and the work efficiency is improved. You can

Further, in the case of performing a trailer work for towing a cart or the like, if the main gearshift lever 4L, the sub gearshift lever 3L and the reverse gearshift lever 5L are operated to the high speed side after the main switch 6S is turned ON, the The pin-shaped lever regulating portion 63 of the lever regulating portion 63 described above is used for the forward / reverse switching lever 7
Since the backward movement of L is regulated, the forward movement of the forward / backward movement switching lever 7L causes the aircraft to efficiently travel in a high speed state, while automatically preventing the trouble caused by the backward movement at a high speed.

Thereafter, when any one of the main speed change lever 4L, the auxiliary speed change lever 3L and the reverse speed change lever 5L is operated to the low speed side, the lever restricting portion 63 retreats, so that the reverse operation of the forward / backward changeover lever 7L becomes possible. The tractor can then reverse at the desired reverse speed.

[0033]

As described above, according to the present invention, the lever 4L,
The gear shift levers 4L, 4K are provided with gear shift mechanisms 4K, 3K for shifting the traveling speed of the aircraft in a plurality of stages by operating 3L, and the forward / reverse gear shift mechanism 7 for switching between forward and backward movements by operating the forward / reverse shift lever 7L. In a work vehicle for operating the forward / backward switching lever 7L at the traveling speed selected by operating the lever 3L to move the vehicle forward or backward, the reverse speed changing mechanism 5K can select the reverse speed for the forward / reverse speed changing mechanism 7. Since the reverse speed change mechanism 5K is operated by the reverse speed change lever 5L so as to set a desired reverse speed in advance, the forward / reverse switch lever 7L can be operated to perform the forward / backward movement. It is possible to appropriately and appropriately switch the speed at the time of reverse travel to promote the work safely and efficiently.

Further, according to the present invention, the forward / reverse switching lever 7 is used.
A lever regulating portion 63 is provided on L, and the shift levers 4L, 3
When L is tilted to the high speed side, the lever restricting portion 63 prevents the forward / reverse switching lever 7L from being operated to the reverse side, so that the reverse operation at high speed is restricted, so that even a beginner can perform trailer work with peace of mind. Can be done.

[Brief description of drawings]

FIG. 1 is a transmission operation diagram of a traveling transmission of a work vehicle according to the present invention.

FIG. 2 is an enlarged view of a main part of the traveling transmission shown in FIG.

FIG. 3 is a plan view of a forward / reverse switching lever and a lever guide.

FIG. 4 is a check circuit diagram of a reverse speed control mechanism.

[Explanation of symbols]

3K auxiliary transmission 3L auxiliary shift lever 4K main transmission 4L main shift lever 5K reverse gear 5L Reverse shift lever 7 Forward / reverse speed change mechanism 7L Forward / reverse switching lever

Claims (2)

[Claims] Claims: 1. A transmission mechanism 4K, 3K for changing the traveling speed of the aircraft in a plurality of stages by operating the levers 4L, 3L, and a forward and reverse transmission mechanism 7 for switching between forward and backward movement by operating the forward and backward switching lever 7L. And the shift lever 4
At the traveling speed selected by operating the L or 3L lever,
In a work vehicle for operating the forward / reverse switching lever 7L to move the vehicle forward or backward, the forward / reverse speed changing mechanism 7 is provided with a reverse speed changing mechanism 5K for selecting a reverse speed.
Operate the reverse speed change mechanism 5K with the reverse speed change lever 5L,
A traveling transmission system for a work vehicle, wherein a desired reverse speed is set in advance. 2. The forward / reverse switching lever 7L is provided with a lever restricting portion 63, and when the shift levers 4L, 3L are tilted to the high speed side, the lever restricting portion 63 causes the forward / reverse switching lever 7L to move backward. The traveling speed change device for a work vehicle according to claim 1, wherein the transmission is disabled.