JPH0720431Y2 - Auxiliary transmission of agricultural tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an auxiliary transmission that can perform an ultra-low speed shift in an agricultural tractor.

[Problems to be Solved by Prior Art and Invention] It is generally known that, in this type of agricultural tractor, a sub-gear shaft is loosely fitted with a gear to be used as an ultra-low speed idle gear. By the way, recently, it is further required to make a fine traveling shift based on the field condition and the working condition, and therefore, it is proposed that the auxiliary shift is also made in multiple stages.

Conventionally, however, it is common to have two sub-shifts, and in the case of three sub-shifts, if all the gears are loosely fitted gears, the low-speed gear becomes large and it becomes difficult to obtain an appropriate reduction ratio. In addition, there is a problem that a speed change gear that slides and slides must be added.

[Means for Solving the Problem] The present invention has been made in view of the above circumstances, and an object thereof is to provide an auxiliary transmission device for an agricultural tractor capable of eliminating these drawbacks. Power of the pinion shaft via the main transmission 14 and the sub transmission 15
In the agricultural tractor configured to be transmitted to the 42, when the power is transmitted from the auxiliary transmission shaft 34 of the auxiliary transmission to the pinion shaft 42, the auxiliary transmission shaft 34 is integrally rotated with the auxiliary transmission shaft. A low-speed gear 53 that is fixed to move, a free-wheel gear 58 that is fitted so as to freely rotate in the axial direction, and an intermediate-speed gear 55 and a high-speed gear 56 that are integrally formed with each other, and a spline fitting that is movable in the axial direction. And an ultra-low speed gear 61 that rotates integrally with a small gear 62 that is always meshed with the idle gear 58 by the movement in the axial direction.
Alternatively, a slide gear 54 that selectively meshes with a dog gear 57 formed on the idle gear 58 is provided, and a pinion shaft is provided.
The low-speed gear 42 is fitted around the shaft 42 so that it can rotate freely.
A low speed intermediate gear 46 in which a gear and a dog gear 46a which are constantly meshed with 53 are integrally formed with a dog gear 46 which is spline-fitted so as to be movable in the axial direction and moves in the axial direction.
a, a transmission gear 43 in which a low-medium speed gear 43a that selectively meshes with the medium-speed gear 55 and a high-speed gear 43b that selectively meshes with the high-speed gear 56 are integrally formed.

Further, the present invention is configured as described above, and is capable of suppressing the increase in size of the low-speed gear and eliminating the need to add a speed-changing gear, while being able to perform sub-shifting in three stages in addition to ultra-low speed. .

[Embodiment] Next, a configuration of the present invention will be described with reference to an embodiment shown in the drawings. FIG. 1 shows a configuration diagram of a power transmission device in an agricultural tractor. 1 is clutch housing,
Reference numeral 2 is a center case, 3 is a spacer, 4 is a transmission case body, 5 is a rear axle case, and the clutch housing 1 has a main clutch 6 for connecting and disconnecting power input from the engine E, a main shaft 7, reduction gears 8, 8a and The front wheel drive take-out portion 9 is internally provided, and the center case 2 has a power transmission shaft 10 made of a pipe shaft and a front wheel drive take-out shaft 11 fitted to the power transmission shaft 10 so as to be relatively rotatable. on the other hand,
The spacer 3 includes a PTO transmission 12 including a transmission gear 12b slidably fitted on a PTO transmission shaft 12a, and three gears having different diameters.
36, 36a, 36b are integrally formed with a distribution gear 13, a main transmission 14 of the traveling portion, and the like, and a sub transmission 15, a differential 16 and the like are installed in the transmission case body 4. There is. The spacer 3 is integrally joined to the mesh case body 4 to form a mesh case (rear mesh case) M with the both 3 and 4. The rear axle case 5 has a brake 17, a reduction gear 18, and a rear axle 19. A holder 20 is bolted to the center case 2, and bearings 21, 22, 23 are fitted in the holder 20.

The spacer 3 is attached to the mesh case body 4 together with the center case 2 by bolts, and bearings 24, 25, 26, 27, 28 are fitted in the spacer side wall portions.

The mission case M is installed below the driver's seat,
The upper position of the center case 2 connecting the mesh case M and the clutch housing 1 is a space (step) of the driver's feet, and the power transmission shaft 10 should be arranged in a stepped shape lower than the main shaft 7. Thus, the step surface is made as low as possible and flat (flat step).

By the way, the main transmission shaft 29 of the main transmission device 14 supported by the bearings 23, 27 is composed of a pipe shaft, and the outer diameter spline portion is engaged with the transmission gears 32, 33 that slide with the forks 30, 31. The auxiliary transmission shaft 34 of the auxiliary transmission 15 is fitted and connected to the inner diameter spline portion. In FIG. 1, a boss 35 having an inner diameter spline is fitted and fixed to the inner end of the pipe-shaped main transmission shaft 29.
A structure in which one end side of the main transmission shaft 29 and one end side of the auxiliary transmission shaft 34 are engaged with each other via 35 is exemplified. Further, the central gear 36 of the distribution gear 13 is constantly meshed with the idle gear 38 of the reverse shaft 37. Bearings 39 and 4 are provided on the center wall of the case body 4.
0 and 41 are fitted and support the auxiliary transmission shaft 34 and the pinion shaft 42. A speed change gear 43 is slidably provided on the pinion shaft 42 through an auxiliary speed change lever P, and a shaft end portion of the pinion shaft 42 is loosely fitted in a position fixed state through a bush 44 and a liner 45. Low speed intermediate gear 46 with dog gear 46a
have. The dog gear 46a meshes with the low-to-medium speed gear 43a of the speed change gear 43, whereby a low speed auxiliary speed change is performed.

47 and 48 are spline joints, 49 is a front wheel side differential device, 50 is a front wheel, 51 is a rear wheel, and 52 is a flyhole.

The sub-transmission shaft 34 has a low speed gear 53 fixed on the shaft and a slidable slide gear (also referred to as an ultra-low speed gear or SL gear) 54. A freewheel gear 58 in which a gear 55, a high speed gear 56 and a dog gear 57 are integrally formed is loosely fitted, and the freewheel gear 58 is positionally fixed by a retaining ring 60 via a liner 59. Further, the slide gear 54 slides on the sub-transmission shaft 34 by the ON / OFF operation by the ultra-low speed lever Q to turn ON.
When it is operated to the side, it meshes with the reduction gear 61, and when it is operated to the OFF side, it meshes with the dog gear 57.
Then, in a state where the slide gear 54 meshes with the reduction gear 61, the idle gear 58 serves as a reduction gear for ultra-low speed, and in a state where the slide gear 54 meshes with the dog gear 57, a medium-high speed auxiliary shift is configured. There is.

When the slide gear 54 and the reduction gear 61 mesh with each other, the transmission gear on the pinion shaft 42 is locked by the check mechanism (not shown) of the external link.
The low gear 43a for low and medium speeds only meshes with the medium speed gear 55 of the idle gear 58.

Further, a small gear 62 is integrated with the reduction gear 61 by spline engagement. The holder 63 is supported by bearings 64 and 65. The small gear 62 and the high speed gear 56, the low speed gear 53, the low speed gear 53 and the low speed gear 46 are always in mesh with each other.

On the other hand, when the auxiliary transmission lever P is operated to the medium speed position with the ultra-low speed lever Q in the OFF state, the low / medium speed gear 43a moves to the medium speed gear 55.
When the vehicle is operated to the high speed position, the high speed gear 43b meshes with the high speed gear 56 to perform the high speed auxiliary shift.

The ultra-low speed lever Q may be provided separately from the auxiliary transmission lever P (see FIG. 6) or may also be used as the auxiliary transmission lever P (see FIG. 5).

In the figure, 66 is the PTO shaft, 67 is the driver's seat, 68 is the main transmission lever, and 69.
Is a traveling steering wheel, 70 is a flat step surface, and 71 is a driver's foot space.

In the above-mentioned structure, the power from the engine E is connected to the main clutch 6 so that the main shaft 7 and the reduction gears 8 and 8 are connected.
a, the power transmission shaft 10, and the spline joint 47 are sequentially transmitted to the distribution gear 13 to integrally rotate the three gears 36, 36a, 36b having different diameters. When the gear shift gear 32 or 33 sliding on the main gear shift shaft 29 is shifted from the neutral position (N) to a predetermined gear shift position by operating the main gear shift lever 68, the distribution gears.
13 and the speed change gears 32 or 33 selectively mesh with each other according to the speed change position, and the main speed change shaft 29 rotates, so that the auxiliary speed change shaft 34 integrally fitted and connected to the main speed change shaft 29 rotates in the same direction. The low speed gear 53 fixed on the sub transmission shaft 34 and the slide gear 54 coaxially spline-engaged also rotate. Due to the rotation of the low speed gear 53, the low speed gear 46 meshing with the low speed gear 53 idles on the pinion shaft 42.

Then, with the ultra-low speed lever Q operated to the OFF position,
Depending on the position of the speed change gear 43 sliding on the pinion shaft 42 in accordance with the operation of the auxiliary speed change lever P, the speed change gear 43 is the low speed intermediate gear 46, the idling gear 58, the medium speed gear 55, or the high speed gear 56. The pinion shaft 42 rotates at a low speed, a medium speed, or a high speed by engaging with either of the above. This rotational force is differential to the rear side.
Rear wheel 51 transmitted to rear wheel 19 via 16 and reduction gear 18
While driving the front wheel 50, the front wheel 50 is transmitted to the front side via the front wheel drive take-out shaft 11, the front wheel drive take-out section 9 and the differential device 49 which are integrally connected to the pinion shaft 42.

The gear shift of the PTO shaft 66 is performed by operating the gear shift lever (not shown) of the PTO gearbox 12.

On the other hand, in trencher work and digging work using a tractor, the aircraft speed is usually set to an ultra-low speed (1 km / h or less). In this case, the ultra-low speed lever Q is used.
When operated to the ON side, the slide gear 54 on the auxiliary transmission shaft 34 slides backward (to the right in FIG. 1) and meshes with the reduction gear 61, so the reduction gear ratio of the small gear 62 and the high speed gear 56 is multiplied. The pinion shaft 42 is rotated at the reduction ratio.

[Effects] Since the present invention is configured as described above, the transmission gear 43 is formed on the low speed intermediate gear 46 with the slide gear 54 meshed with the dog gear 57 of the idle gear 58. Dog gear
46a, by selectively meshing with the medium-speed gear 55 and the high-speed gear 56 formed on the free-wheel gear 58, power transmission is performed on the pinion shaft 42 in a state in which low-, medium-, and high-speed auxiliary shifts are performed in three stages. , The slide gear 54 is meshed with the ultra-low speed gear 61, and the transmission gear 43 is meshed with the idling gear 58, so that the pinion shaft 42
The power transmission is carried out in the state where the sub-shift at an ultra-low speed is performed.

As a result, the sub-shift to the pinion shaft is a combination of three low, medium, and high speed shifts plus an ultra-low speed, and finer shifts can be performed, but in that case, low and medium speed shifts are not possible. , The low-medium speed gear 43a formed in the speed change gear 43 is selectively meshed with the dog gear 46a and the medium speed gear 55 formed in the low-speed intermediate gear 46 which is constantly power-transmitted from the auxiliary speed change shaft. In particular, it is possible to simplify the structure without providing a low-speed transmission gear mechanism, and to move the low-speed transmission gear, which has a large diameter, in the axial direction in order to intermittently transmit the power transmission. There is no need to secure space for it.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a power transmission device in an agricultural tractor according to the present invention, FIG. 2 is a configuration diagram of the power transmission device, and FIG.
FIG. 4 is a side view of an agricultural tractor equipped with the present invention, FIG. 4 is a schematic view showing the arrangement of gears in a mesh case,
FIG. 5 is a plan view showing the shape of the lever guide when one lever is used for both the sub-shift lever and the ultra-low speed lever.
The drawing is a front view showing the shape of the lever guide when the auxiliary shift lever and the super shift lever are provided separately. In the figure, 10 is a power transmission shaft, 11 is a front wheel drive take-out shaft, and 12 is a PTO.
A transmission, 14 is a main transmission, 15 is a sub transmission, 29 is a main transmission shaft, 34 is a sub transmission shaft, 24 is a pinion shaft, 43 is a transmission gear on a pinion shaft, 46 is a low speed intermediate gear, and 53 is A low speed gear fixed to the sub-transmission shaft, 54 is a slide gear, 55 is a medium speed gear, 56 is a high speed gear, 57 is a dog gear, 58 is an idle gear, 61 is a reduction gear, 62 is a small gear, and 66 is a PTO shaft. , M is a case.

Claims (1)

[Scope of utility model registration request] 1. A main transmission (1
4) In the agricultural tractor configured to be transmitted to the pinion shaft (42) via the sub transmission (15), the sub transmission shaft (34) of the sub transmission to the pinion shaft (42) When transmitting power by means of a low speed gear (53) fixed to the auxiliary transmission shaft (34) so as to rotate integrally with the auxiliary transmission shaft (34).
And an idle gear (58) which is fitted so as to freely rotate around the axis and in which the medium speed gear (55) and the high speed gear (56) are integrally formed.
And an ultra-low speed gear (61) that is spline-fitted so as to be movable in the axial direction and that rotates integrally with a small gear (62) that is always meshed with the idle gear (58) by the axial movement or the idle gear. The dog gear (57) formed in (58) is provided with a slide gear (54) that selectively meshes, and the pinion shaft (42) is fitted in the pinion shaft (42) so as to be free to rotate in the axial direction, and the low speed gear ( 53) and a low speed intermediate gear (46) integrally formed with a gear and a dog gear (46a) are axially movably spline-fitted, and the dog gear (46a) is moved by the axial movement. ), A transmission gear (43) integrally formed with a low-medium speed gear (43a) selectively meshing with the medium speed gear (55) and a high speed gear (43b) selectively meshing with the high speed gear (56). Auxiliary speed change device for agricultural tractors.