JPS627024Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transmission system for an agricultural tractor, particularly an ultra-low speed transmission called a creep transmission.

Creep speed is slower than the normal low speed for onion and yam cultivation, and was designed to allow ultra-low speeds to be achieved without reducing engine speed. It's about gaining speed.

Conventionally, in order to obtain this creep speed, a configuration has been adopted in which the reduction gear on the creep shaft is bypassed from the low speed of the sub-shift. However, in this conventional configuration, the creep shaft was disposed at a separate, protruding position, resulting in a problem that the mission device became larger.

In order to reduce the size of the transmission case, the present invention provides a gear for switching between the sub-shift and creep shift on the pinion shaft, and switches between the sub-shift and creep shift between the main shaft 16, pinion shaft 17, and creep shaft 21. It consists of a mechanism.

By interlocking this sliding gear with the auxiliary transmission sliding gear, the auxiliary transmission and creep transmission are made compact and can be accommodated in a narrow space.

The purpose of the present invention is as described above, and the structure of the present invention will be explained based on the structure of the embodiment shown in the attached drawings.

FIG. 1 is an overall side view of the agricultural tractor of the present invention.

An engine 2 is disposed within a bonnet 1, and a front axle bracket 3 protrudes forward from the engine 2. The front axle bracket 3
The front differential case 5 is supported by the front differential case 5, and the front wheels 6 are supported by a front axle that projects laterally from the front differential case 5. The front differential case 5 is driven by a front wheel drive shaft inside the front wheel drive shaft cover 4. A clutch housing 7 is fixed to the rear surface of the engine 2, and a transmission case 8 is fixed to the rear surface of the clutch housing 7. A rear axle housing protrudes from the side surface of the transmission case 8 or the rear axle case, and the rear wheel is supported by the rear axle housing.

A PTO shaft 9 protrudes from the rear surface of the transmission case 8, and power is transmitted to the working machine via a universal joint. Operation levers protrude from the left and right sides of the transmission case 8. A PTO shift lever 58 is provided on the left side, a front clutch lever 55, a sub-shift/creep shift lever 50 are provided on the right side, and a main shift lever 69 is provided protruding from the top surface. The side PTO shift lever 58, front clutch lever 55, and auxiliary shift/creep shift lever 50 use the fender 11 surfaces on both sides of the seat 11 as shift guide plates. 13 is a hydraulic case, and 12 is a steering handle.

FIG. 2 is an exploded cross-sectional view showing the gear train of the transmission device of the present invention. I will explain its structure and at the same time explain its function.

The driving force of the engine 2 is connected and disconnected by a main clutch device within a clutch housing 7, and is transmitted to an input shaft 14 protruding from a transmission case 8.
A main shaft 16 whose front end is supported by a bearing in a hole in the rear end face of the input shaft 14 is supported at the rear on the same axis as the input shaft 14 . Shafts are arranged at respective positions of a square shape with the input shaft 14 and the main shaft 16 as vertices. A front power take-off shaft 20 and a creep shaft 21 are arranged on the same axis below a pinion shaft 17 having a pinion 17a carved on the right side when facing the direction of travel.

Also, there is a counter shaft 1 on the left side when facing the direction of travel.
8 and a PTO transmission shaft 19 are arranged.

The power input from the input shaft 14 is transmitted to the fixed gear 1
5 and is transmitted to the counter shaft 18 via a fixed gear 26.

Further, power is further transmitted from the fixed gear 26 to the PTO speed change shaft 19 via the fixed gear 30 on the PTO speed change shaft 19.

The main shift lever 69 described above allows three forward speeds and one reverse speed change. As shown in FIG. 4, the main gear shift lever 69 consists of two shifter forks 62 and
61 is configured to selectively slide on the shifter shafts 62a, 61a. The shifter fork 62 causes the sliding gear 22 on the main shaft 16 to slide back and forth, resulting in one speed change between reverse and forward, and the shifter fork 61 causes the double sliding gears 23 and 24 on the main shaft 16 to move back and forth. Shifts to 2 forward speeds and 3 forward speeds.

In the reverse gear, the rotation of the counter shaft 18 is the fixed gear 2.
8, the double loose fit gear 35 on the pinion shaft 17.
34 and 35 are always meshed, and the sliding gear 22
meshes with the other 34 of the double loose fit gear, resulting in a reverse gear.

The second forward stage is one of two sliding gears 23 and 24 23
is obtained by meshing with a part of the fixed gear 28.

In the first forward stage, the same sliding gear 22 is the counter shaft 1.
This is achieved by meshing with the fixed gear 27 on top of the 8.

Three forward speeds are obtained by the other two sliding gears 24 meshing with the fixed gear 29 on the counter shaft 18.

The rotation after the main shift is transmitted from the engraved gear 33 of the main shaft 16 to the larger diameter 39 of the two loosely fitted gears 39, 43 on the pinion shaft 17.

This loosely fitted gear 39 is divided into a normal sub-shift and a creep speed. When the wide sliding gear 41 on the creep shaft 21 is slid to the right, it simultaneously meshes with the loose fit gear 39 on the pinion shaft 17 and another gear 38 of the same shape, and becomes the auxiliary transmission drive side.

In this state, the auxiliary transmission sliding gear 37 meshes with the internal gear of the loose fit gear 38, resulting in a low speed of the auxiliary transmission. By meshing the sliding gear 37 with the fixed gear 25 on the main shaft 16, high speed sub-shifting can be achieved.

This sub-shift operation is achieved by sliding the sliding gear 37 back and forth by operating the sub-shift/creep shift lever 50 shown in FIG.

When the sub-shift/creep shift lever 50 is operated, the wide sliding gear 41 on the creep shaft 21 also operates back and forth, thereby switching between the sub-shift state and the creep state.

When the wide sliding gear 41 is slid forward, it disengages from the loosely fitted gear 39, remains engaged with the gear 38, and the front end engaging portion 4 of the wide sliding gear 41 disengages.
1a is an engaging portion 42 integrated with the creep shaft 21
The rotation of the creep shaft 21 is transmitted to the gear 38.

Let me explain the power transmission system in a creep shift state.

Fixed gear 33 on main shaft 16 and double loose fit gear 3
One 39 of 9 and 43 meshes, and this rotation is transmitted from the other 43 to the fixed gear 40 on the creep shaft 21, causing the creep shaft 21 to rotate.
The rotation of the creep shaft 21 is transmitted from the engagement portion 42 to the other end engagement portion 41a of the wide sliding gear 41, and from the wide sliding gear 41 to the gear 38.

As described later, a sub-transmission shifter fork 54,
Since the creep shifter 66 is operated in association with one sub-shift/creep shift lever 50, the wide sliding gear 41 is on the creep shift side,
That is, before moving forward, the auxiliary transmission sliding gear 37 is always in mesh with the internal gear of the loose fit gear 38, and is in a position to transmit the rotation of the loose fit gear 38 to the pinion shaft.

On the other hand, when the sub-shift is operated to raise or lower, the creep shift is always canceled and the wide sliding gear 41
is at the position where the loosely fitted gears 39 and 38 should be integrated via the wide sliding gear 41.

The front power take-off shaft 20 is driven by:
This is only when the pinion shaft 17 is rotating for rear wheel drive, and the rotation of the pinion shaft 17 is limited to the fixed gear 3.
Loosely fitted gear 4 on the front power take-off shaft 20 from 6
5 will be informed. By engaging the engaging portion 44a of the clutch slider 44 with the engaging portion 45a of the loose-fit gear 45, the front wheels 6 are connected from the front power take-off shaft 20 to the front wheel drive shaft in the front wheel drive shaft case 4. It is driven. 46 is a front power extraction shaft case.

PTO shifting is achieved by the sliding of the sliding gear 31 for PTO shifting, low speed PTO shifting is achieved by the engaging portion 31a engaging with the engaging portion 32a of the loosely fitted gear 32, and middle speed PTO shifting is achieved by sliding. A high speed PTO shift is achieved by the gear 31 meshing with the fixed gear 28 on the counter shaft 18, and a high speed PTO shift is achieved by the engaging portion 31b engaging the engagement portion of the loosely fitted gear 30 on the PTO shift shaft 19. It will be done.

Figure 3 is a sectional view of the final reduction part of the PTO shaft 9,
The figure is a front sectional view of the transmission case, FIG. 5 is a sectional view of the shifter fork 66 part of the clutch transmission section, FIG. 6 is a rear sectional view of the transmission case, and FIG. 10 is the sub-shift/creep shift lever 50.
FIG. 7 is a plan view of the auxiliary transmission/creep shift lever, FIG. 8 is a side view thereof, and FIG. 9 is a shift guide groove of the auxiliary shift/creep shift lever.

The PTO shift lever 58 slides a shifter fork 60 on a shifter shaft 60a by an arm 59a fixed to a lever shaft 59, and the shifter fork 60 slides the PTO shift sliding gear 31 shown in FIG. 2 in three positions forward and backward. and perform PTO gear shifting.

The front clutch lever 55 uses an arm 56a fixed to a lever shaft 56 to slide a shifter fork 57 on a shifter shaft 57a, and the shifter fork 57 moves the clutch slider 44 on the front power take-off shaft 20 back and forth, thereby controlling the front drive. Perform disconnection.

As shown in FIG. 10, this shifter shaft 57 also serves as a shifter shaft 57a for the front clutch.
A shifter fork 66 for creep shifting is provided with a loose fit at the rear of the shifter a. The shifter fork 66 moves the wide sliding gear 41 on the creep shaft 21 back and forth to switch between the sub-shift and the creep shift. This shifter fork 66 is attached to the lever arm 6.
4a, operated by the creep shift arm 65 via the lever shaft 64.

As shown in FIG. 6, this arm 65 is connected via a link 63 to an end of a creep shift locking plate 51 loosely fitted onto the lever shaft 53. Therefore, when the lever 50 is engaged with the locking plate 51 and rotated by rotating the sub-shift/creep shift lever 50 from side to side about the pin 70, the link 63 and the arm 6 are rotated.
5. The wide sliding gear 41 slides back and forth on the creep shaft 21 via the lever shaft 64, the arm 64a, and the shifter fork 66, thereby switching between the sub-shift and the creep shift.

When the lever 50 is rotated to the left in the auxiliary transmission position, it engages with the groove on the side of the locking plate 52 on the auxiliary transmission side, and when it is rotated back and forth in this state, the lever shaft 53 is rotated by the pin 71 of the locking plate 52. The shifter fork 54 on the shifter shaft 54a moves back and forth via the arm 53a, and the sliding gear 37 for the auxiliary transmission is moved back and forth, thereby achieving high and low speeds for the auxiliary transmission.

In order to operate the sub-shift high or low in this way, it is necessary to turn off the creep shift and keep the wide sliding gear 41 and the loose-fit gears 39 and 38 in mesh with each other; conversely, when the creep shift is engaged, Since the auxiliary gear shift is in the low position and the loose gear 38 and pinion shaft 17 need to be integrated, this can be improved by configuring both gear shift levers to select a locking plate using a single lever. This is what I did. That is, by configuring the shift guide groove as shown in FIG. 9, the above-mentioned gear relationship can be reliably obtained as the lever 50 is operated, and shift errors will not occur.

As described above, the present invention has three main shafts 16, pinion shafts 17, and creep shafts 21 that transmit rotation after main gear shifting.
The shafts of books are arranged in parallel, and the fixed gear 33 on the main shaft 16 and the larger diameter loose-fit gear 39 of the double loose-fit gears 39 and 43 on the pinion shaft 17 are always meshed, and the loose-fit gear 39 and A gear 38 of the same shape is placed and fixed on the pinion shaft 17, and a smaller-diameter loose-fit gear 43 of the double loose-fit gears is attached to the fixed gear 4 on the creep shaft 21.
0, an integrated engaging portion 42 is provided at the end of the creep shaft 21, and an end of the wide sliding gear 41 is loosely fitted onto the creep shaft 21 and is slidable. The wide sliding gear 41 and the other end engaging portion 41a are slid on the creep shaft 21, and the wide sliding gear 41 is connected to the loosely fitted gear 39 on the pinion shaft 17. By meshing with both of the gears 38, a sub-speed stage is obtained, and the wide sliding gear 41 engages only with the gear 38, and the end engaging portion 4
1a is engaged with the engaging portion 42 on the creep shaft 21 to obtain a very low speed stage and drive the pinion shaft 17, so that the following effects are achieved.

First, the sub-shift and the creep shift are performed on the main shaft 16.
The transmission case can be configured between three shafts: the pinion shaft 17 and the creep shaft 21, and the creep shaft 21 can also be used as the sub-transmission shaft as in the past, making the transmission case smaller. It was possible to do so.

Second, from the main shaft 16 that transmits the rotation of the main transmission,
Rotation is transmitted to the creep shaft 21 via the gear on the pinion shaft 17, and the power transmission path is returned to the pinion shaft 17 again, so the three shafts are not arranged in a triangular shape. They can be arranged in a straight line, and this also makes it possible to effectively utilize the space within the mission case and reduce the size of the case itself.

[Brief explanation of the drawing]

Fig. 1 is an overall side view of the agricultural tractor of the present invention, Fig. 2 is an exploded cross-sectional view of the axis showing the gear train of the transmission device, Fig. 3 is a cross-sectional view of the final reduction part of the PTO shaft 9, and Fig. 4 is a cross-sectional view of the final reduction part of the PTO shaft 9. Front sectional view of the case
Figure 5 is a sectional view of the shifter fork 66 part of the creep transmission section, Figure 6 is a rear sectional view of the transmission case, Figure 7 is a plan view of the auxiliary transmission/creep transmission lever, and Figure 8 is a side view. , Figure 9 shows the shift guide groove of the sub-shift creep shift lever, the first
Figure 0 is a diagram showing a support portion of the sub-shift/creep shift lever. 16... Main shaft, 17... Pinion shaft, 21...
Creep shaft, 37... Sliding gear for sub-transmission, 38
...Gears fixed to the pinion shaft, 39, 43...
Double loose fitting gear on pinion shaft, 40...Fixed gear, 41...Sliding gear for creep speed change, 41a
...Other end engaging portion, 42...An integrated engaging portion.

Claims (1)

[Scope of utility model registration request] Three shafts, the main shaft 16, pinion shaft 17, and creep shaft 21, which transmit the rotation after the main gear shift, are arranged in parallel, and the fixed gear 33 on the main shaft 16 and the double loosely fitted gears 39 and 43 on the pinion shaft 17 are arranged in parallel. Of these, the larger diameter loose fit gear 39 is always in mesh, and a gear 38 having the same shape as the loose fit gear 39 is placed and fixed on the pinion shaft 17, and of the two sets of loose fit gears, the smaller diameter loose fit gear 43 is A wide shaft is always meshed with the fixed gear 40 on the creep shaft 21, has an integrated engagement part 42 at the end of the creep shaft 21, and is fitted loosely on the creep shaft 21 so as to be slidable. An end engaging part 41a is also provided at the end of the sliding gear 41, and the wide sliding gear 41 and the other end engaging part 41a are slid on the creep shaft 21, so that the wide sliding gear 41 is connected to the pinion shaft. By meshing with both the loosely fitted gear 39 and the gear 38 on the gear 17, a sub-shift stage is obtained, and the wide sliding gear 41 engages only with the gear 38, and the end engaging portion 41a
1. A transmission device for an agricultural tractor, characterized in that the transmission device is configured to obtain a very low speed gear by engaging with the engagement portion 42 on the top of the gearbox 1 and drive the pinion shaft 17.