JPH0328336B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a gear shift operation mechanism in a technology in which a transmission gear for an agricultural tractor is provided with a lower speed creep gear in addition to a normal gear.

(b) Prior Art It has been known to attach a creep transmission device to an agricultural tractor, which is slower than the normal speed, as disclosed in Japanese Patent Application Laid-Open No. 56-31825.

However, in the past, a creep gear shift lever was provided separately in the creep gear kit, or a mounting position for the creep gear shift lever was provided in the transmission case.

However, in order to enable creep shifting, this required unnecessary machining on the basic transmission case, which did not require creep shifting.

(C) Problems to be Solved by the Invention The present invention solves the problems of the conventional creep transmission device, and has three transmission levers: a main transmission lever, an auxiliary transmission lever, and a creep transmission lever. The structure is such that the auxiliary shift lever can also perform creep shifting so that there is no need to provide a device. Moreover, of course, if the creep transmission mechanism is not required, the sub-shift lever becomes the only lever.

(d) Means for solving the problem The purpose of the present invention is as described above. Next, the configuration for achieving the purpose will be explained.

Lid body 6 that closes the side opening of mission case 1
A creep gear kit is constructed by protruding a bearing boss part from 3, supporting the shafts 8, 7, and 9 on the bearing boss part, and supporting the creep gear/creep transmission slider 53 on the shafts 8, 7, and 9. The creep gear kit is inserted and fixed from the opening side of the mission case 1, and the lid body 63 is inserted into the mission case 1.
A shifter shaft 58 for operating the slider 53 and an actuated body 57 fixed to the shifter shaft 58 are protruded from a protruding part of the transmission case 1, and the rotation of the sub-shift lever 64 disposed outside the transmission case 1 A shifting sliding shaft 61 for a sliding sub-shifting is arranged horizontally at the upper part of the transmission case 1.
1, an auxiliary transmission operating rod 65 is protruded from the upper part of the transmission case 1, and a creep transmission operating rod 66 is provided protruding from the side of the transmission case 1. It can be engaged with an actuated body 57 protruding from the lid body 63.

(E) Embodiment The object and structure of the present invention are as described above, and the structure and operation of the embodiment shown in the attached drawings will be explained below.

FIG. 1 is a side sectional view of a transmission device for an agricultural tractor according to the present invention. The second is also a top view. FIG. 3 is a side sectional view of the creep transmission gear kit.

First, let's explain the overall configuration from FIG. 1.

The rotation of the engine is transmitted to the PTO drive shaft 13 and the main shaft 4 via a dual-clutch type main clutch device.

Four loosely fitted gears 31, 32, 33 on the main shaft 4,
34 is loosely fitted. and 4 free-fit gears 3
1, 32, 33, and 34 are counter shafts 5, respectively.
It is constantly meshed with the upper fixed gears 35, 36, 37, and 38.

Then, by selectively moving the shifter forks 45, 46 on the gear shifter shafts 41, 43 back and forth, constant mesh type gear shifting is performed.
Main gear shifting is possible. This main transmission does not have a reverse shift, but the sub-shift has a reverse shift, but either one is fine.

The rotation of the main gear after shifting is transmitted to the sub-transmission device through the gear 15 at the rear end of the counter shaft.

The sub-transmission device is shifted to three forward speeds and one reverse speed when a creep speed change gear kit is not installed.

That is, the first forward speed is achieved by the shifter fork 47 causing the slider 28 to engage with the engagement pawl 18a. It is transmitted from gear 15 → gear 16 → cylinder shaft 2 → gear 17 → gear 18, → engaging claw 18a → slider 28 → pinion shaft 12.

The second forward speed is achieved by the shifter fork 48 engaging the slider 29 with the engaging pawl 19a.
Gear 15 → Gear 16 → Slider 29 → Engagement pawl 1
9a→gear 19→gear 20→pinion shaft 12.

The third forward speed is achieved by the slider 28 meshing with the engaging pawl 15a, whereby the counter shaft 5 and the pinion shaft 12 are directly connected.

The reverse speed is determined by the slider 29 meshing with the engaging pawl 21a, so that the gear 15→gear 16→cylindrical shaft 2→
This is obtained by the following sequence: slider 29 → engaging claw 21a → gear 21 → reverse gear 23 → gear 22 → pinion shaft 12.

A reverse gear 23 is shown in FIG. 2, the shaft 14 of which serves to lock the beginning of the parking brake band. 24 is a parking brake disc.

The gear 22 is the gear 2 of the ground PTO extraction shaft 6.
5 are engaged. In addition, when removing the bottom cover of the transmission case 1 and installing the front wheel drive gear kit, attach the gear 2 to the ground PTO extraction shaft 6.
6 is attached. 41, 42, 43, and 44 are shifter shafts.

A hydraulic pump device 30 is attached to the PTO drive shaft 13, and the hydraulic pump device 30 is attached to the rear wall surface of the mission case 1.

The pinion shaft 12 is supported by tapered roller bearings 11 and 10, and the bearing case 3 of the tapered roller pair 11 and 10 is mainly supported by the insertion opening 62a of the rear axle case 62.

Further, the bearing case 3 is also fitted into the fitting opening 1a of the front transmission case 1 for support. In other words, the bearing case 3 itself functions like a dowel pin between the transmission case 1 and the rear axle case 62.

With this configuration, the bearing case 3
Conventionally, the ring gear of the differential device was supported by bearings on the rear axle case 62 side, and the pinion gear 12a of the pinion shaft. This solved the problem of not being able to mesh accurately and causing the gears to jam.

The structure of the creep gear kit, which is the main part of the present invention, will be explained with reference to FIG.

The creep gear kit has a bearing boss projecting from a lid 63 that closes a side opening of the transmission case 1, supporting shafts 8, 7, and 9 on the bearing boss, and supporting gears on the shaft.

When this creep gear kit is inserted through the side opening of the transmission case 1, the gear 49 on the input side meshes with the gear 17 shown in FIG. 1, and the gear 56 on the output side meshes with the gear 20 shown in FIG. be.
Both gears are always meshed.

In the case of creep forward gear, the slider 53 meshes with the engagement pawl 54a, and the gear 17→gear 4
9 → shaft 7 → gear 54 → gear 55 → gear 56 → gear 20 → pinion shaft 12.

In the case of creep reverse gear, the slider 53 meshes with the engagement pawl 52a, and the gear 17→gear 4
9 → shaft 7 → gear 52 → gear 50 → gear 51 → gear 55 → gear 56 → gear 20 → pinion shaft 12.

58 is a shifter shaft, and 59 is a shifter arm, which operates the shifter fitted into the slider 53.

That is, by moving the slider 53 back and forth using a shifter, a creep forward gear and a creep reverse gear can be obtained.

The speed of the creep reverse gear is considerably lower than the normal reverse gear of the auxiliary gear, and by changing the creep reverse gear and the main gear, a speed that matches the snow blower mounted at the rear can be achieved. It will be done.

FIG. 4 is an enlarged side sectional view of the sub-transmission section. FIG. 5 is a rear cross-sectional view of the case where there is only a sub-transmission device and no creep transmission gear kit. FIG. 6 is an enlarged rear sectional view when a creep gear change gear kit is installed. FIG. 7 is a diagram similarly showing the direction in which the gear shift lever 64 is operated.

What is shown in FIG. 4 is a structure in which the engagement portion with the detent ball 69 of the shifter shaft also serves to prevent the gear from coming off with the engagement claws 19a, 21a of the slider 29. There is.

In this case, if the shifter fork 48 is positioned too accurately with the detent ball 69, friction will occur between the shifter fork 48 and the insertion groove of the slider 29 due to the reaction force from the detent portion.
This prevents either the shifter fork 48 or the slider 29 from being worn out. Therefore, the fitting groove 70 of the detent ball 69 is provided with a margin in the axial direction. The slider 28 and shifter fork 47 have the same structure.

In FIG. 5, the creep gear change gear kit is not installed, and the right side opening of the transmission case 1 is closed by a mere lid 67 to which the creep change gear kit is not installed.

The upper opening of the transmission case 1 is closed by a lid 70, and a speed change sliding shaft 61 is supported. An operating rod 65 projects downward from the speed change sliding shaft 61, and is configured to fit into the engagement grooves of the shifter forks 48, 47 for selection. Another operating rod 66 is configured downward on the speed change sliding shaft 61, and this operating rod 66 is connected to the double engagement prevention fitting 60.
The actuated member 57 is fixed to the shifter shaft 58 and protrudes upward, and is fitted into a recessed portion thereof.

Furthermore, as shown in FIG.
8, 47, and the actuated body 5 for creep shifting
7, the double mesh prevention metal fitting 60 is provided so that creep shifting is performed after the shifters 48, 47 return to the neutral position. 68 is a sub-shift guide case, and 64 is a sub-shift lever 64.

As shown in FIG. 7, the gear shift lever guide of the auxiliary gear shift lever 64 is configured in the shape of a king, and has a total of 6 forward gears, 3 forward gears, 1 reverse gear, and creep forward/reverse gears.
The speed is changed.

(F) Effects of the Invention Since the present invention is configured as described above, it has the following effects.

First, a single sub-shift lever 64 performs sub-shift and creep shift, making switching easy. or,
It has a simple structure and is easy to operate.

Second, even if a creep transmission is not installed, all you need to do is remove the creep transmission gear kit.
All you have to do is leave the area around the sub-shift lever as it is.

Therefore, even if a creep gear kit is installed, there is no need to change the inside of the transmission case.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of the transmission of the present invention. Second
The figure is also a top view. FIG. 3 is a side sectional view of the creep transmission gear kit. FIG. 4 is an enlarged side sectional view of the sub-transmission section. FIG. 5 is a rear cross-sectional view of the case where there is only a sub-transmission device and no creep transmission gear kit. FIG. 6 is an enlarged rear sectional view when a creep gear change gear kit is installed. FIG. 7 is a diagram showing the direction in which the sub-shift lever 64 is operated. DESCRIPTION OF SYMBOLS 1...Mission case, 53...Slider, 58...Shifter shaft, 57...Actuated body for creep shifting, 59...Shifter arm, 61...
Shift sliding shaft, 63... Lid body, 65... Sub-transmission operating rod, 66... Creep shifting operating rod, 64...
Sub-shift lever.

Claims (1)

[Claims] 1 A bearing boss protrudes from the lid 63 that closes the side opening of the transmission case 1, the shafts 8, 7, and 9 are supported on the bearing boss, and creep gears and creep gears are mounted on the shafts 8, 7, and 9. A creep gear kit is configured by supporting the speed change slider 53, and the creep gear kit is inserted and fixed from the opening side of the transmission case 1, and the lid body 63 is attached to the transmission case 1.
A shifter shaft 58 for operating the slider 53 and an actuated body 57 fixed to the shifter shaft 58 are protruded from a protruding part of the transmission case 1, and the rotation of the sub-shift lever 64 disposed outside the transmission case 1 A shifting sliding shaft 61 for a sliding sub-shifting is arranged horizontally at the upper part of the transmission case 1.
1, an auxiliary transmission operating rod 65 is protruded from the upper part of the transmission case 1, and a creep transmission operating rod 66 is provided protruding from the side of the transmission case 1. A creep transmission mechanism for an agricultural tractor, characterized in that it can be engaged with an actuated body 57 protruding from a lid body 63.