JP3483706B2 - Tractor mission - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to tractor missions.

[0002]

2. Description of the Related Art When performing work with a tractor, for example, when performing deep plowing / crushing soil plowing work on a rotary, trencher work, etc., ultra-low speed (creep shift) is required. In some cases, a creep transmission is provided separately from the main transmission and the auxiliary transmission as disclosed in (1). In this conventional example, the size of the mission is increased, and the gear shift operation system must be individually provided, and the structure and the handling are complicated.

As a technique for improving this point, Japanese Patent Publication No. 61-
There is one disclosed in Japanese Patent No. 25933 (conventional example).

[0004]

The conventional example disclosed in the above publication has the following problems although it is useful as such. That is, since the intermediate case is provided between the clutch housing and the transmission case that form the tractor vehicle body, and the auxiliary transmission and the creep transmission are incorporated (accommodated) in the intermediate case, the front-rear length of the tractor vehicle body is reduced. It became too large and the wheelbase became long, making it difficult to meet the needs of utility tractors (general-purpose tractors).

Further, in constructing a creep transmission,
A separate creep shaft was required, which resulted in the need for bearings, which increased the number of parts, making parts management cumbersome, complicating the assembly process, and increasing the number of processed parts. . Therefore, according to the present invention, a rear opening is formed at a rear end of a clutch housing which constitutes a vehicle body of a tractor, and the opening is closed by a mission case while the auxiliary transmission and the creep transmission are accommodated in the opening. Therefore, it is an object to provide a mission adapted to a utility tractor which has a long wheelbase and is easy to assemble and disassemble.

[0006]

The present invention takes the following technical means in order to achieve the above-mentioned object. That is, according to the present invention, the main transmission device 9 and the shuttle transmission device for switching the power transmitted from the main clutch 7 to the main transmission device 9 to the forward / reverse direction are provided to the traveling transmission system that is interlocked with the engine 1 via the main clutch 7. 8, the sub transmission 10 and the creep transmission 1 to which the power from the main transmission 9 is transmitted.
1, a clutch housing 2 that constitutes the vehicle body of the tractor includes a first chamber 3 that accommodates the main clutch 7.
And a second chamber 4 accommodating the shuttle transmission 8 and the main transmission 9 together, and a rear opening 5 is formed at the rear of the second chamber 4 and the same second chamber is formed. The shuttle transmission (8) and the main transmission (9) housed in (4) are coaxial with each of the transmission main shaft (25) and the transmission auxiliary shaft (26) which are installed so as to be parallel to each other in the axial direction. A mission case 6 which is provided side by side in the axial direction, accommodates the sub transmission 10 and the creep transmission 11 in the rear opening 5, and accommodates the rear opening 5 in the rear wheel differential device 13. The transmission case 6 is blocked by the front wheel power connection / disconnection device 1 in front of the rear wheel differential device 13.
2 is accommodated, and by adopting such a configuration, the wheel base does not become long and the assembling and disassembling is facilitated (Claim 1).

Further, in the present invention, the auxiliary transmission 10 is capable of switching between high and low stages, and the creep transmission 11 is adapted to obtain a creep shift on the low speed side of the auxiliary transmission 10. As a result, the required creep speed change can be secured without wasteful creep speed change, which facilitates the speed change operation.
4 ). Further, in the present invention, the auxiliary transmission device 10 and the creep transmission device 11 are juxtaposed in the front and rear in the axial direction, and the creep transmission device 11 comprises the constituent shaft 3 of the auxiliary transmission device 10.
Since it is configured with 4, 35, a separate dedicated creep shaft is not necessary to secure the creep speed change, the number of parts is reduced, parts management is easy, and the number of machining is small. Therefore, a cheap mission can be provided (Claim 4 ).

Further, in the present invention, the auxiliary shaft 35, which is a constituent shaft of the auxiliary transmission 10, is the transmission main shaft 25 of the main transmission 9.
Since the transmission shaft 34, which is the constituent shaft of the sub transmission 10, is arranged on the extension of the sub shaft 26 of the main transmission 9, the transmission operation system can be integrated. Therefore, the transmission can be simplified and made compact, and the transmission loss of the speed change operation system is small, which enables light speed change (claim 4).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, which schematically shows the overall configuration of a tractor mission, a clutch housing 2 which is connected to a rear surface of an engine 1 and constitutes a vehicle body of the tractor together with the engine 1 includes a first chamber 3 and a second chamber 4. Are provided in series in the front-rear direction, the rear portion of the second chamber 4 is a rear opening portion 5, and a transmission case 6 is connected to the opening end by bolt joining or the like to close the opening portion 5. Here, the engine 1, the clutch housing 2, and the transmission case 6 substantially constitute the vehicle body of the tractor.

The first chamber (clutch chamber) 3 of the clutch housing 2 accommodates a main clutch 7, and the second chamber 4 is a shuttle transmission as a traveling transmission system which is interlocked with the engine 1 via the main clutch 7. The device 8 and the main transmission device 9 are accommodated, the auxiliary transmission device 10 and the creep transmission device 11 are further accommodated in the rear opening 5, and the transmission case 6 includes a front wheel power connection / disconnection device 12, a rear wheel diff device 13, and the like. PTO
The system includes a hydraulic clutch device 14 and the like. As shown in FIG. 2, the main clutch 7 is attached to a flywheel 15 of an engine, and a propelling shaft 17 of a traveling system is connected to the propelling shaft 17 via a damper means 16. The clutch release means 19 is fitted on the shaft portion of the propulsion shaft case 18, and the main clutch 7 shown by a diaphragm type is engaged and disengaged through sliding of the release means 19 in the figure, and the propulsion shaft 17 is intermittently connected. It is designed to be rotated.

The propulsion shaft case 18 is fitted in an opening (substantially circular in a front view) formed in a partition wall 20 for substantially partitioning the first chamber 3 and the second chamber 4. Part 18A
Is integrally provided at the base portion thereof, and the insertion fitting portion 18A is provided at the partition wall 20.
The base portion 18B is bolted to the partition wall 20 by fitting the opening portion of the base portion 18B from the front. Insertion portion 18A of the propulsion shaft case 18
Has bearing fitting recesses 18C and 18D in two upper and lower stages,
Cylindrical shaft 1 with its shaft center aligned with the bearing fitting recess 18C in the upper stage
8E extends forward, and the propulsion shaft 17 is attached to the tubular shaft portion 18E.
And the front and rear ends of the propulsion shaft 17 are inserted into the bearings 21 and 2.
It is rotatably supported by 2.

The propulsion shaft 17 is a cylinder shaft, and the rear portion thereof is formed as a slightly expanded diameter portion 17A and is supported by a bearing 22 and enters the second chamber 4, and the flywheel 15 is disposed in this cylinder.
A PTO propulsion shaft 24, which is connected to the shaft via a joint 23, is inserted so as to be relatively rotatable. As shown in FIG. 2 and FIG. 3, the shuttle transmission 8 and the main transmission 9 housed in the second chamber 4 are respectively provided in the transmission main shaft 25 and the transmission auxiliary shaft 26 that are installed so as to be parallel to each other in the axial direction. It is provided coaxially in a line in the axial direction.

That is, the transmission main shaft 25 has a cylindrical shaft structure, is located on the extension line of the axis of the propulsion shaft 17, and its front portion is inserted into the bulging portion 17A of the propulsion shaft 17 and supported by the needle bearing 25A. The rear portion is supported by the second partition wall 27 by the bearing 25B, and the transmission auxiliary shaft 26 is supported by the bearings 26A, 26B in the front and rear thereof. Furthermore,
The shuttle transmission device 8 and the main transmission device 9 are both synchromesh gear shifts, and the transmission main shaft 25 is positioned at the upper part and as the input side, and the speed change auxiliary shaft 26 is positioned at the lower part and the output side. 28 is provided on the transmission main shaft 25, and the shuttle transmission 8 has a second
It is arranged on the front side of the chamber 4 and on the side close to the engine 1, and the main transmission 9 is arranged on the rear side of the second chamber 4 and on the side far from the engine 1.

As described above, by providing the synchronous transmission means 28 on the traveling main shaft 25 on the input side close to the engine 1, the torque becomes smaller than that provided on the traveling auxiliary shaft 26. As a result, even if the diameter is small, there is no problem, and this makes it possible to reduce the height and lateral width of the clutch housing 2, and as shown in FIG. 9, it is easy to mount the boarding / alighting step 2B. Became a virtual line, but it became easier.
The length of the shift fork that slides on the synchronous transmission means 28 can be shortened, and the sliding can be made lighter.

The shuttle transmission 8 by the synchronous articulated gear shift is mounted on the bulging portion 17A of the propulsion shaft 17 for the first transmission.
The gear 8A, the second gear 8B that is engaged with the first gear 8A and is provided on the speed change counter shaft 26, and the second gear 8B.
A third gear 8C integrally formed with the third gear 8C, and a fourth gear which is linked to the third gear 8C via an idle gear 8D and is provided on the traveling transmission main shaft 25 behind the first gear 8A. 8E, the first gear 8A and the fourth gear 8E
When the synchronous speed change means 28 interposed between and is slid in the direction of arrow F in FIG. 1, it is forward (normal rotation), and when it is slid in the direction of arrow R, it is reverse (reverse) and is neutral. It is possible to switch back and forth including.

Main transmission 9 by synchronous articulated gear shifting
In the embodiment, the four-speed shift from the first speed (1F) to the fourth speed (4F) is possible.
To the first speed transmission gear 9D in this order, the travel transmission main shaft 25 is rotatably fitted and supported in a row on the travel transmission main shaft 25.
Above, the fourth to the first transmission transmission gears 9E, 9F, 9 which are in mesh with corresponding to the transmission gears 9A, 9B, 9C, 9D.
G and 9H are fixed, and the fourth speed transmission gear 9A and the third
Synchronous speed change means 28 is interposed between the high speed transmission gear 9B and between the second speed transmission gear 9C and the first speed transmission gear 9D, respectively. Four
By sliding in the F direction, it is possible to perform a four-speed shift including neutral.

The synchronous transmission means 28 of the shuttle transmission 8 and the main transmission 9 are shown as a key type inertia lock type in the drawing, but a pin type inertia lock type or a constant load type may be used. However, it may be a servo type. Further, the second of the clutch housing 2
A rectangular opening 2A is formed on the upper wall corresponding to the chamber 4 as shown in FIGS. 2 and 5, and the lid 30 that detachably closes the opening 2A is attached to the main transmission 9. A gear shift lever 31 for operating the synchronous gear shift means 28 is provided upright, and a shift rod having a shift fork sliding on the gear shift lever 31 is supported on the inner surface of the lid body 30 so as to be slidable back and forth. An operation shaft 32 for operating the synchronous transmission means 28 of the shuttle transmission 8 is supported in the lateral direction on the side wall of the clutch housing 2.

As described above, by arranging the shuttle transmission 8 and the main transmission 9 coaxially in the second chamber 4 of the clutch housing 2 in the axial direction, the speed change operation system (the speed change lever 31, the operation shaft). 32) and the like to facilitate the operation, and to open the opening 5 at the rear of the clutch housing 2.
By forming the clutch housing 2, all of the shuttle transmission 8, the main transmission 9, the auxiliary transmission 10, and the creep transmission 11 can be assembled to the clutch housing 2, and the needs of utility (general-purpose) tractors can be met. It is possible to deal with it.

Further, since the synchronous transmission means 28 of the shuttle transmission 8 and the main transmission 9 are coaxially arranged side by side in the axial direction on the traveling transmission main shaft 25 having a light operating load, the operation can be made lighter. The shift fork etc. can be shortened and the height and width of the vehicle body can be narrowed. This makes it possible to mount the loading and unloading steps provided on the left and right side walls of the vehicle body in a wide and reliable manner, and to provide a utility tractor that is light and easy to get on and off. Of. 3 and 4, details of the auxiliary transmission device 10 and the creep transmission device 11 which are housed in the rear opening 5 of the clutch housing 2 are shown.

In FIGS. 1, 3 and 4, the traveling speed change auxiliary shaft 26 projects rearward from the second partition wall 27 and enters the opening 5, and the protruding part 26C is forward from the shaft end. It has a recessed portion 26D formed by hollowing out, and is provided with a first gear 33 for auxiliary transmission and an engaging portion 33A. The transmission shaft 34 is arranged on the extension of the traveling speed auxiliary shaft 26,
A front portion of the transmission shaft 34 is inserted into the recess 26B and supported by a bearing 34A, and a rear portion of the transmission shaft 34 is supported by a bearing 34B provided at a rear edge portion of the rear opening 5, and The bearing 34B extends rearward.

A sub-transmission auxiliary shaft 35 having a tubular shaft structure is arranged on the axial extension of the traveling transmission main shaft 25, and the front portion of the auxiliary shaft 35 is supported by a bearing 35A fitted in a bearing retainer 36. The rear portion of the sub shaft 35 is supported by a bearing 35B, and the transmission shaft 34 and the sub shaft 35 are arranged vertically above each other in parallel with each other in the axial direction. Thus, by disposing the sub shaft 35 on the extension of the main shaft 25 of the main transmission and by disposing the transmission shaft 34 on the extension of the main shaft 26 of the transmission, the transmission operation system can be integrated. The transmission loss of the gear shifting operation system is reduced, enabling lighter gear shifting.

The bearing retainer 36 is bolted to the rear surface of the second wall 27 to position the bearing 25B, and the bearing 35A fitted to the retainer 36 is attached to the rear portion of the traveling transmission main shaft 25 and the auxiliary shaft. It is located across the front of 35. On the sub-transmission sub-shaft 35, a reduction second gear 37 meshing with the first gear 33 and a small-diameter third gear 38 integrally formed with the second gear 37 are interposed via a needle bearing or the like. A sub gear shift lower side fourth gear 39 meshing with the third gear 38 is rotatably fitted onto the transmission shaft 34 via a needle bearing or the like.

The fourth gear 39 has an engaging portion 39A,
The occlusal portion 39A and the occlusal portion 33A formed on the protruding portion 26C are axially opposed to each other.
A shifter 40 that can be engaged with and disengaged from 39A is slidably provided on the transmission shaft 34. Therefore, by sliding the shifter 40 in the direction of the arrow H in FIG. 1 to engage with the interlocking portion 33A, the traveling speed change auxiliary shaft 26 and the transmission shaft 34 are directly connected to each other to achieve the auxiliary shift height. 1 is slid in the direction of the arrow L in FIG. 1 to engage the shifter 40 with the interlocking portion 39A to obtain a low auxiliary shift, and the auxiliary transmission 10 is neutralized by sliding the shifter 40. It is possible to shift to high and low speeds, including

In the rear opening 5 of the clutch housing 2, an auxiliary transmission 10 and a creep transmission 11 are housed side by side in the axial direction, and the creep transmission 1 is accommodated.
1 is configured without using a separate shaft by utilizing the constituent shafts of the auxiliary transmission device 10 (the sub shaft 35 and the transmission shaft 34), which reduces the number of parts and facilitates assembly and disassembly. Further, the creep shift is ensured only on the low speed side of the auxiliary transmission 10 instead of on the high speed side, so that unnecessary shift speeds are eliminated and only the required creep shift is obtained.

That is, in FIG. 1 and FIG. 3, the low speed third gear 39 of the auxiliary transmission 10 is provided with the creep input gear 41 integrated with the third gear 39, and the creep input gear 41 is fitted over the transmission shaft 34. The input gear 4 is provided on the auxiliary transmission auxiliary shaft 35.
1, a reduction gear 42 meshing with 1 and a creep output gear 43 having a diameter smaller than that of the gear 42 are arranged side by side in the axial direction.
A large-diameter creep gear 44 that meshes with the creep output gear 43 is provided on the transmission shaft 34 so as to be relatively rotatable.
4 is provided with a creep shifter 45 which can be engaged with and disengaged from an occlusal portion 44A of the creep gear 44. The shifter 45 slides in the direction of arrow C in FIG. By joining the shaft 34 to the shaft 34, it is possible to ensure the creep shift in the low speed range of the auxiliary transmission 10.

Sub transmission 10 and creep transmission 1
The transmission shaft 34 which shares the transmission of 1 is projected rearward from the bearing 34B, and the bevel pinion type differential drive shaft 46 of the rear wheel differential device 13 is provided on the axial extension of the transmission shaft 34. It is arranged in the mission case 6, and the projecting portion of the transmission shaft 34 and the front portion of the differential drive shaft 46 are interlocked and coupled by a shaft coupling 47, and on the shaft coupling 47,
A front wheel power switching shifter 48 is slidably fitted by a spline or the like. The shifter 48 slides in the direction of arrow D in FIG. 1 to engage with an engagement portion 49A of a front wheel drive gear 49. The front wheel transmission gear 50, the front wheel transmission shaft 5
The power is synchronized with the front wheels while driving the rear wheels via 1 etc., and here, rear wheel drive and all-wheel drive for the front and rear wheels can be selected.

The front wheel drive gear 49 is fitted and supported by the protrusion of the transmission shaft 34 via a needle bearing or the like.
In the lower part of the clutch housing 2, the traveling speed change auxiliary shaft 26
A front wheel transmission gear 50 that meshes with the drive gear 49 is provided on a transmission shaft 51 that is installed in parallel with the transmission shaft 34. Here, the front wheel power connecting / disconnecting (switching) device 12 can be configured without employing a counter shaft or the like, which also reduces the number of parts and facilitates assembly / disassembly.

Further, by disposing the transmission shaft 34 and the differential drive shaft 46 on the same axis, as shown in FIGS. 7 and 8, the auxiliary shift shifter 40, the creep shifter 45, and the front wheel connecting / disconnecting shifter 48. Can be configured as shifters having the same diameter, and the shift fork 52, the fork shaft 53, the operation support shaft 54, etc., which engage with the respective shifters 40, 45, 48,
Since it is possible to use the same parts, it is possible to expect reduction of the number of parts, management of stock parts, improvement of operability, etc. from this point as well. With reference to FIGS. 1 and 4, etc., the PTO propulsion shaft 24 in which the propulsion shaft 17, the traveling transmission main shaft 25, and the auxiliary transmission auxiliary shaft 35 are respectively inserted is shown in FIG.
Is connected to the transmission shaft 56 via the PTO hydraulic clutch 14 having the elastic buffer shaft joint 55 in the front upper part of
The transmission shaft 56 is a so-called externally mounted PTO transmission 58 in the rear surface of the transmission case 6, and a PTO transmission 58 in a PTO transmission case 57.
The PTO shaft 59 can be linked to gear shifting in conjunction with.

The PTO hydraulic clutch 14 is engaged and disengaged by causing pressure oil from a control valve (not shown) to act on the pressurizing piston 14A and press-contacting a plurality of clutch plates 14B.
The return oil of the clutch is used as a forced lubricating oil for the synchronous speed change device 28. That is, the oil passages 24A, 5 communicating with the PTO transmission shaft 56 and the PTO propulsion shaft 24 with each other.
6A is formed in the axial direction, and clutch return oil (or clutch cooling oil may be supplied) is supplied to the passages 24A and 56A. Inject lubricating oil into the slight gap,
By forming a radial lubricating oil ejection hole in the speed-change main shaft 25 so as to correspond to the synchronous speed-change means 28, the synchronous speed-change means 2 is formed.
8 is provided with the lubricating oil liquid feeding means 60 for the sliding portion.

With this structure, even if the traveling speed changing main shaft 25 is provided with the synchronous speed changing means 28, the lubrication of the means 28 is ensured and the speed change can be performed smoothly and lightly with less troubles. Of. The second chamber 4 of the clutch housing 2, the transmission case 6 and the like contain gear lubricating oil (oil surface is indicated by L), and this lubricating oil flows into the clutch chamber 3 (first chamber). In order to prevent this, an oil ring is attached to the outer periphery of the insertion portion 18A of the propulsion shaft case 18, and the bearing portion 61 and the bearing 22 of the front wheel transmission shaft 51 are provided with an oil seal 62.
An oil seal 63 is provided to prevent the forced lubricating oil from leaking into the propulsion shaft case 18 (see FIG. 2).

In addition, the front wheel transmission shaft 51 is inserted into the bearing portion 61 in the lower portion of the clutch chamber 2 and extends along the lower surface of the engine oil pan 64 to interlock with the front wheel differential drive shaft (not shown). It does not matter in which case the gears are interlocked with the front wheel differential drive shaft through the opening 65 formed in the bottom wall of the second chamber 4 , and in the former case, the opening 65 is closed by a lid with a seal. In the latter case, the bearing 61 is closed by the lid with a seal.

[0032]

As described above in detail, according to the present invention, it is not necessary to lengthen the wheel base of the tractor in the mission including the auxiliary transmission and the creep transmission.
It is possible to provide a utility tractor that can ensure the required creep speed and is excellent in operability.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a side sectional view of the first half of the mission showing the embodiment of the present invention.

FIG. 3 is a side sectional view of a mission intermediate portion showing an embodiment of the present invention.

FIG. 4 is a side sectional view of a second half of the mission showing the embodiment of the present invention.

FIG. 5 is a plan view of the front half of the vehicle body showing the embodiment of the present invention.

FIG. 6 is a plan view of the rear half of the vehicle body showing the embodiment of the present invention.

FIG. 7 is a side sectional view of an auxiliary transmission and a creep transmission showing an embodiment of the present invention.

FIG. 8 is a front sectional view of the auxiliary transmission and the creep transmission showing the embodiment of the present invention.

FIG. 9 is a front view (elevation surface) of a vehicle body showing an embodiment of the invention.
It is a figure.

[Explanation of symbols]

1 engine 2 clutch housing 5 Rear opening 6 mission case 7 Main clutch 9 Main transmission 10 Auxiliary transmission 11 creep transmission 13 Rear wheel differential device 25 Travel speed change spindle 26 Traveling speed auxiliary shaft

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-6-278484 (JP, A) JP-A-62-120227 (JP, A) JP-A-61-25933 (JP, A) JP-A-53- 112369 (JP, A) JP-A-60-104867 (JP, A) Actually developed Sho-52-160770 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60K 17/02-17 / 08 F16H 57/02 A01B 51/00-61/04 A01B 63/14-67/00 B62D 49/00

Claims (4)

(57) [Claims] 1. A main transmission mechanism connected to an engine (1) via a main clutch (7) is connected to a main transmission clutch (7).
A shuttle transmission (8) for switching the power transmitted through the propulsion shaft (17) between forward and reverse, and this shuttle transmission
Shifting forward / reverse power transmitted from the device (8)
A main transmission (9), said main transmission power from (9) and a secondary transmission (10) and creep transmission is transmitted (11), a clutch housing (2 constituting the body of the tractor ) Includes a first chamber (3) accommodating the main clutch (7) and a second chamber (4) accommodating both the shuttle transmission (8) and the main transmission (9).
The second chamber is provided by partitioning with the partition wall (20)
The rear part of (4) is partitioned by the partition wall (27), and two partition walls
The shuttle transmission (8) and the main transmission (9) housed in the second chamber (4 ) between (20, 27) are the two compartments.
The transmission main shaft (25) and the transmission auxiliary shaft (26), which are installed in parallel with each other in the axial direction by the walls (20, 27) , are coaxially provided side by side in the axial direction, and the second chamber ( 4) A rear opening (5) is formed at the rear of the rear opening (5), and the auxiliary transmission (10) and the creep transmission (11) are housed in the rear opening (5) to form the rear opening (5). ) Is closed by a mission case (6) accommodating a rear wheel differential device (13). (12) A tractor mission, characterized in that it is housed. 2. The first chamber (3) and the second chamber (4) are separated from each other.
The propeller shaft case (18) is bolted to the partition wall (20)
Fixed, main clutch to this propulsion shaft case (18)
Propulsion shaft connected to (7) and protruding into the second chamber (4)
The rear part of (17) is supported via bearings (22)
The transmission main shaft through the bearing (25A) on the propulsion shaft (17)
The front part of (25) is supported, and the propulsion shaft case (18) is provided.
The front part of the speed change counter shaft (26) is supported by the bearing (26A).
Of the transmission main shaft (25) and the transmission auxiliary shaft (26)
Bearings (25B, 26B) on the partition wall (27)
The tractor mission according to claim 1, wherein the tractor mission is supported via . 3. A second chamber connected to the main clutch (7).
The shuttle gearbox is attached to the propulsion shaft (17) that has entered into (4).
A first gear (8A) for forward drive of the device (8) is provided,
The transmission main shaft (25) whose front part is supported by the propulsion shaft (17)
4th gear (8E) for reverse drive and switching between forward and reverse
A plurality of shift gears of the primary shift device (28) and the main shift device (9).
(9A, 9B, 9C, 9D) and the front
The second gear (8B) and the fourth gear which mesh with the first gear (8A)
Formed integrally with the third gear (8C) that meshes with the gear (8E)
The transmission gears (9A, 9A,
9B, 9C, 9D) and transmission transmission gears (9E, 9)
F, 9G, 9H) is provided on the speed change counter shaft (26)
Mission of the tractor according to claim 1 or 2, characterized in that are found provided freely idle. 4. The auxiliary transmission (10) is switched between high and low two stages.
And the creep transmission (11) is
To get a creep shift on the low speed side of the transmission (10)
The auxiliary transmission (10) and the creep transmission (11)
And are arranged side by side in the axial direction.
The device (11) is a shaft (34, 34) of the auxiliary transmission (10).
The auxiliary shaft (35), which is a constituent shaft of the auxiliary transmission (10), is arranged on the axial extension of the transmission main shaft (25) of the main transmission (9), (10)
4. The transmission shaft (34), which is a constituent shaft of the main transmission device (9), is arranged on an axial extension of the speed change auxiliary shaft (26) of the main transmission device (9). Tractor mission.