JP2519058B2 - Tractor power transmission device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power transmission device in a tractor for agriculture or the like.

2. Description of the Related Art In an agricultural tractor, an engine is mounted on the front part of a vehicle body and a mission case is mounted on the rear part. The output shaft of the engine is connected to the input shaft of the mission case via a propeller shaft. A transmission mechanism is built in the mission case, and engine power input to the input shaft is transmitted to the output shaft through the transmission mechanism.
Wheels are driven by the output shaft. The transmission case is further provided with a PTO shaft, and the input engine power is also transmitted to the PTO shaft at a variable speed, and the power is transmitted to the working machine connected to the tractor via the PTO shaft.

A main clutch is inserted in a traveling drive system for driving the wheels so that the drive system can be disconnected from the engine at any time during a gear shift operation or the like, and the main clutch is provided close to the engine. Is normal. By the way, it is desirable that the PTO drive system that transmits power to the work machine via the PTO shaft operates independently of the traveling drive system, that is, regardless of the traveling state of the tractor.

Therefore, in order to connect the PTO drive system to the engine without passing through the main clutch of the traveling drive system, the power transmission device of the tractor has conventionally been configured as shown in FIG. 1, for example. In FIG. 1, E is an engine mounted on the front of the vehicle body, and the output shaft 01 of the engine is the engine E.
Is connected to a hollow tubular shaft 04 so as to be connectable and disconnectable via a main clutch 03 in a clutch housing 02 provided adjacent to the. The shaft 04 extends into the rear transmission case 05, and in the transmission case 05, between the shaft 04 and a shaft 06 disposed in parallel with and adjacent to the shaft 04, a gear train T ₁ ... T _{4 is formed.} A transmission is formed. The gear on the shaft 06 side of each gear train is rotatably fitted on the shaft 06. By connecting one of these gears to the shaft 06 by the selector 07, the rotation of the shaft 04 is desired. The gear ratio is transmitted to the shaft 06.
The shaft 06 is connected to the differential 08 via the final shaft 07, via which the wheels are driven. That is, the main clutch 03, the shaft 04, the gear train T, the shaft 06, and the final shaft 07 constitute a traveling drive system 09 of this power transmission device.

The PTO drive system 010 of this power transmission device is configured as follows. A shaft 011 is directly connected to the output shaft 01 of the engine E, the shaft 011 penetrates through the hollow shaft 04, extends to the rear portion of the mission case 05, and is connected to the shaft 013 via a PTO clutch 012. A transmission similar to the transmission in the traveling drive system is provided between the shaft 013 and the shaft 014 so that the rotation of the shaft 013 is transmitted to the shaft 014 in a variable speed and transmitted to the PTO shaft 015. It has become. In this way, since the PTO drive system 010 is directly connected to the engine E without passing through the traveling drive system 09, the PTO shaft can be driven independently of the engine E regardless of the traveling state of the tractor.

Further, there is also one that employs a transmission structure as described in Japanese Utility Model Publication No. 57-109022.

Problems to be Solved by the Invention In the conventional general tractor power transmission device as described above, since the main clutch is provided on the engine side, it is necessary to provide a special clutch housing. For this reason, it is difficult to extend the engine direct coupling shaft that does not pass through the main clutch into the transmission case.To this end, the traveling drive system shaft 04 coupled to the main clutch is a hollow shaft as described above. There was no choice but to adopt a complicated shaft structure such as passing the engine directly connected shaft 011 through the hollow shaft.

Further, the engine direct connection shaft 011 has to be a long shaft extending from the engine E to the rear part of the mission case 05.

Means and Actions for Solving Problems The present invention has been made in view of such circumstances, and in the present invention, a traveling drive system for driving wheels and a PTO drive system for driving a working machine are provided. In a power transmission device for a tractor that has, one input shaft connected to an engine is provided in a mission case, and first and second drive gears are provided side by side on an output shaft of the input shaft in the mission case. A second gear in which the first drive gear is connected to a main clutch of a traveling drive system via a first gear train, and the second drive gear is arranged behind the first gear train. Connected to the PTO clutch of the PTO drive system via a row, the main clutch and the PTO clutch are arranged to be shifted front and back, and the main shaft provided with the input shaft and the main clutch and the PTO clutch are provided. PTO The transmission shaft and the transmission shaft are oriented parallel to each other, and the front end of the PTO transmission shaft is located rearward of the main clutch, and the main clutch and the PTO clutch are overlapped in the vertical direction. Deploy.

According to the present invention, since the main clutch is connected to the input shaft and provided in the transmission case, a clutch housing is not particularly required. Also, only one connected to the engine
Since the traveling drive system and the PTO drive system are taken out in parallel from the input shaft of the book, the PTO drive system is operated independently of the traveling drive system without using the double shaft structure of the inside and outside as in the conventional example. It is possible to shorten the axis of the PTO drive system.

Further, since the main clutch and the PTO clutch are arranged so as to vertically overlap with each other, the vertical width of the mission case can be reduced and the position of the PTO shaft can be increased.

Embodiment FIG. 2 shows an embodiment of the present invention and is a system diagram of a power transmission device in a transmission case of a tractor. The main clutch case 2 is integrally attached to the front end of the mission case 1, and the input shaft 5 is attached to the front wall 1a of the mission case 1 and the main clutch case 2 via bearings 3 and 4, respectively.
Is pivotally supported. The input shaft 5 is connected to the engine 70 via a flyhole 71 and a drive shaft 72, and is constantly rotating during engine operation. A gear (first drive gear) 6 is fixedly mounted on the input shaft 5, and the gear 6 is constantly meshed with a gear 8 loosely fitted on a main shaft 7. The rotation of the gear 8 is transmitted to the main shaft 7 via a moat type multi-plate main clutch 9 provided in the main clutch case 2. The main shaft 7 is rotatably supported by the front wall 1a and the intermediate wall 1b of the mission case 1 via bearings 10 and 11. In the transmission case 1, a counter shaft 12 which is also rotatably supported by the front wall 1a and the intermediate wall 1b is arranged adjacent to the main shaft 7, and a main transmission device 13 is provided between the both shafts 7 and 12. Has been.

The main transmission 13 is a third speed drive gear 14, 2 fixed to the main shaft 7.
High-speed drive gear 15, first-speed drive gear 16, reverse-drive gear 17, and counter shaft 12 are loosely fitted and mesh with the gears 14, 15, 16 respectively, third-speed driven gear 18, second-speed driven gear 19, first-speed Driven gear 20
And a reverse driven gear 21 engaged with the reverse driving gear 17 via an idle gear, and the driven gears 18 to
Any one of the counter shafts 21 is rotated through the selector shaft 22 which is rotatable integrally with the counter shaft 12 and is slidable in the axial direction.
By being connected to 12, the rotation of the main shaft 7 is transmitted to the counter shaft 12 at a desired gear ratio.

The counter shaft 12 extends beyond the intermediate wall 1b to the rear part of the transmission case 1, and is connected to the final shaft 24 at the rear part via an auxiliary transmission device 23 composed of a gear mechanism substantially similar to the main transmission device 13. The rotation of the counter shaft 12 is further changed in speed and transmitted to the final shaft 24. The final shaft 24 extends into a rear case 25 attached to the rear end of the mission case 1, and an output bevel gear 26 provided at the rear end of the shaft has a differential gear 27.
, And the rear axle 28 is driven via the differential 27. The final shaft 24 also drives a front wheel drive shaft (not shown) via a gear wheel 29.

The power transmission path described above that branches from the input shaft 5 by the gear 6 to the final shaft 24 constitutes a traveling drive system that drives the wheels of the tractor.

Another drive system, that is, a PTO drive system, branches from the input shaft 5 in parallel to the traveling drive system. That is, a gear (second drive gear) 31 is attached to the input shaft 5 via the one-way clutch 30, and power for driving the PTO shaft is taken out through the gear 31. The one-way clutch 30 allows the torque transmission from the input shaft 5 to the gear 31, but blocks the torque transmission from the gear 31 to the input shaft 5. The gear 31 is an intermediate gear 32 rotatably fitted on the main shaft 7.
an intermediate gear 32b that is in mesh with a and is integral with the intermediate gear 32a
Meshes with the gear 33. First consisting of the gears 6, 8
Is arranged in front of the second gear train composed of the gears 31, 32a, 32b and 33. The gear 33 is the front wall 1a.
And the PTO transmission shaft 36 supported by the bearings 34, 35 on the intermediate wall 1b.
And is connected to the PTO transmission shaft 36 via the PTO clutch 37.

Behind the PTO transmission shaft 36, coaxially with the shaft 36, the front end of the shaft 3
A rear PTO transmission shaft 39, which is rotatably supported at the rear end of the rear end 6 and is pivotally supported at the rear end by a bearing 38 on the rear wall of the rear case 25, is provided with a selector gear 40 slidable in the axial direction. By PT
It can be connected to O transmission shaft 36. Also, the PTO transmission shaft 36
An intermediate PTO shaft 41 is arranged in parallel with the selector gear 40.
By sliding in the axial direction, is engaged with and disengaged from the gear 42 mounted on the intermediate PTO shaft 41. The selector gear 40 meshes with the gear 42 and is located at the left position where the rear PTO transmission shaft 39 is not engaged.
It can occupy three positions, an intermediate position that also engages with the transmission shaft 39 and a right position that does not mesh with the gear 42 and only engages with the rear PTO transmission shaft 39, and depending on these positions, the PTO transmission shaft 36
Rotation of the intermediate PTO shaft 41 only, intermediate PTO shaft 41 only, intermediate PT
Both O-axis 41 and rear PTO transmission shaft 39 or rear PTO transmission shaft 3
Only transmitted to 9.

The intermediate PTO shaft 41 extends forward from the mission case 1 and transmits power to a work machine attached to an intermediate portion of the tractor vehicle body. The rear PTO transmission shaft 39 is connected to the rear PTO shaft 44 via a gear device 43, and the rear PTO shaft 44 transmits power to a work machine mounted on the rear portion of the tractor.

Reference numeral 45 denotes a hydraulic pump that feeds lubricating oil to each lubricating portion in the mission case 1, and is driven by the input shaft 5 via the pump drive shaft 46. Reference numeral 47 is a hydraulic pump (not shown) that supplies hydraulic pressure to a hydraulic cylinder for raising and lowering the working machine, and is driven by a pump drive shaft 48 gear-connected to the pump drive shaft 46.

FIG. 3 is a sectional view showing the structure of a part of the traveling drive system and the PTO drive system more specifically, and the same reference numerals are attached to the similar parts in FIGS. 2 and 3. Supplementing the above description with FIG. 3, the gear 8 that is constantly meshed with the gear 6 mounted on the input shaft 5 is rotatably fitted to the main shaft 7 via the needle bearing 49, and the gear 8 is The clutch outer 50 of the main clutch 9 is connected to. The main clutch 9 is a wet multi-plate type clutch, and its clutch inner 51 is mounted on the front end of the main shaft 7 so as to rotate integrally therewith. The clutch outer 50 and the clutch inner 51 have a large number of clutch plates 52 arranged in a staggered manner.
Are provided so as to be displaceable in the axial direction. A pressure contact plate 53 is fitted to the boss portion of the clutch inner 51 so as to be displaceable in the axial direction, and the pressure contact plate 53 has a protruding piece 53a that protrudes forward through the opening provided in the clutch inner 51. It is connected to the lifter plate 54 through. Lifter plate 54
A spring 55 is interposed between the clutch inner 24 and the clutch inner 24, and the press contact plate 53 presses the clutch plate 52 by the elastic force of the spring 55, whereby the clutch plates 52 are pressed against each other and the main clutch 9 is released. The engine power is transmitted from the input shaft 5 through the main clutch 9 to the main shaft 7. When an operating member such as a pedal provided on the vehicle body is operated, the shaft 57 moves rearward (to the right in the figure) via the operating mechanism 56 interlocking with the operating member, and the lifter plate 54 also moves with it, so that the pressure contact The plate 53 retracts and the main clutch 9 is released.

The gear 31 is loosely fitted to the input shaft 5 via a needle bearing 58, and is connected to the input shaft 5 via a one-way clutch 30. The intermediate gear 32a that meshes with the gear 31 is mounted on the main shaft 7 together with the intermediate gear 32b that is integral therewith.
The gear 33, which is rotatably supported via 9 and meshes with the intermediate gear 32b, is loosely fitted to the PTO transmission shaft 36 via a needle bearing 60. A clutch inner 61 of a PTO clutch 37 is formed integrally with the gear 33, and a clutch outer 62 of the clutch 37 is fixed to the PTO transmission shaft 36. Clutch outer 6
On the inner peripheral surface of 2 and the outer peripheral surface of the clutch inner 61, clutch plates 63 are provided alternately and displaceably in the axial direction, and an operating member 64 is provided behind them by hydraulic pressure supplied through an oil passage 65. By pressing the clutch plates 63, the clutch plates 63 come into pressure contact with each other and the PTO clutch 37
, And the rotation of the gear 33 is transmitted to the PTO transmission shaft 36 via the PTO clutch 37.

At the rear end of the PTO transmission shaft 36, the front end of the rear PTO transmission shaft 39 is rotatably fitted through the needle bearing 66, and the PTO transmission shaft 36
And the rear PTO transmission shaft 39 have splines 6 on the same diameter surface.
7a and 67b are engraved. And these splines 67
The selector gear 40 is slidably engaged with a and 67b. An intermediate gear 68 is interposed between the gear 42 provided on the intermediate PTO shaft 41 and the selector gear 40, and the tooth width of the intermediate gear 68 is formed to be about twice the tooth width of the selector gear 40. When the selector gear 40 is engaged only with the spline 67a and meshes with the intermediate gear 68, as shown by the solid line in the figure, the rotation of the PTO transmission shaft 36 is transmitted only to the intermediate PTO shaft 41 and is shown by the broken line 40a. Selector gear 40 has spline 67a and spline 6
When engaged across 7b and meshing with intermediate gear 68, rotation of PTO transmission shaft 36 is transmitted to both intermediate PTO shaft 41 and rear PTO transmission shaft 39. When the selector gear 40 is further displaced rearward and disengages from the intermediate gear 68 and occupies a position where the selector gear 40 engages with the spline 67a and the spline 67b, the PTO transmission shaft 36 rotates. It is transmitted only to the rear PTO transmission shaft 39.

As described above, in this embodiment, only the input shaft 5 driven by the engine is transferred to the mission case 1
Inside the drive drive system via gears 6 and 31, respectively.
The PTO drive system is branched in parallel with each other, and these two systems are connected to the input shaft 5 by a main clutch 9 and a PTO clutch 37, respectively. Therefore, the power transmission via the traveling drive system and the power transmission via the PTO drive system are performed independently of each other, and the driving state of the working machine by the PTO shaft is not affected by the traveling state of the tractor. Moreover, 2 independent from each other like this
One system can be taken out from one input shaft 5, there is no need to use a complicated double pipe structure for the input shaft as in the past, and the shaft of the PTO drive system is extended forward from the mission case to the engine. Since there is no need for direct connection, the shaft length of the system is shortened.

Since the gear 31 is connected to the input shaft 5 via the one-way clutch 30, even if an excessive load is applied to the working machine,
The resulting torque does not act on or influence the engine and the drive shaft from the engine. Further, the gear 31 is connected to the PT via an intermediate gear 32 loosely fitted to the main shaft 7.
Since it is connected to the gear 33 of the O transmission shaft 36, the width of the transmission case 1 can be narrowed by disposing the PTO transmission shaft 36 below the main shaft 7 and away from the input shaft 5.
It is not necessary to separately provide a shaft that supports 32, the number of parts is reduced, and the mission case 1 is downsized.

As described above, according to the present invention, in the power transmission device of the tractor having the traveling drive system for driving the wheels and the PTO drive system for driving the working machine, one transmission unit connected to the engine in the mission case is provided. An input shaft is provided, first and second drive gears are provided side by side on the output side of the input shaft in the mission case, and the first drive gear is provided through a first gear train to a traveling drive system. Of the main clutch, and the second drive gear is connected to the PTO clutch of the PTO drive system via the second gear train disposed behind the first gear train, The PTO clutch is arranged so as to be shifted front and back, and the input shaft, the main shaft provided with the main clutch, and the PTO clutch provided with the PTO clutch are provided.
The TO transmission shaft and the TO transmission shaft are oriented parallel to each other, and the front end of the PTO transmission shaft is located rearward of the main clutch so that the main clutch and the PTO clutch overlap each other in the vertical direction. The PTO drive system can be operated independently of the traveling drive system without using the dual internal and external input shaft structure as in the prior art, and the axis of the PTO drive system can be shortened. Further, since the main clutch is connected to the input shaft and provided inside the mission case, a clutch housing is not particularly required.

Furthermore, the vertical width of the mission case can be reduced and the position of the PTO axis can be increased.

[Brief description of drawings]

FIG. 1 is a system diagram showing a power transmission device in a conventional tractor, FIG. 2 is a system diagram showing a power transmission device according to the present invention, and FIG. 3 is a partial structure of the power transmission device shown in FIG. It is sectional drawing shown in FIG. 1 ... Mission case, 2 ... Main clutch case, 3,
4 …… Bearing, 5 …… Input shaft, 6 …… Gear, 7 …… Spindle,
8 ... Gear, 9 ... Main clutch, 10, 11 ... Bearing, 12 ...
… Counter shaft, 13 …… Main transmission, 14 …… Third speed drive gear, 15 …… Second speed drive gear, 16 …… First speed drive gear, 17 ……
Reverse drive gear, 18 ... 3-speed driven gear, 19 ... 2-speed driven gear, 20 ... 1-speed driven gear, 21 ... Reverse driven gear, 22 ... Selector, 23 ... Auxiliary transmission device , 24 …… final shaft, 25 …… rear case, 26 …… output bevel gear, 27 …… differential device, 28 …… rear axle, 29 …… gear, 30 …… one-way clutch, 32 …… intermediate gear, 33 …… Gear, 34,35 …… Bearing, 36 …… PTO transmission shaft, 37 …… PTO clutch, 38 …… Bearing, 39 …… Rear PTO transmission shaft, 40 …… Selector gear, 41…
… Intermediate PTO shaft, 42 …… Gear, 43 …… Gear device, 44 …… Rear PTO shaft, 45 …… Hydraulic pump, 46 …… Pump drive shaft, 47
…… Hydraulic pump, 48 …… Pump drive shaft, 49 …… Needle bearing, 50 …… Clutch outer, 51 …… Clutch inner,
52 …… Clutch plate, 53 …… Pressure contact plate, 54 …… Lifter plate, 55 …… Spring, 56 …… Operating mechanism, 57 …… Shaft, 5
8,59,60 …… Needle bearing, 61 …… Clutch inner, 62
...... Clutch outer, 63 …… Clutch plate, 64 …… Operating member, 65 …… Oil passage, 66 …… Needle bearing, 67 …… Spline, 68 …… Intermediate gear, 70 …… Engine, 71 …… Flywheel , 72 …… Drive axis.

Claims (1)

(57) [Claims] 1. A power transmission device for a tractor having a traveling drive system for driving wheels and a PTO drive system for driving a working machine, wherein a transmission case is provided with one input shaft connected to an engine. First and second drive gears are provided side by side on the output side of the input shaft in the mission case, and the first drive gears are connected to a main clutch of a traveling drive system via a first gear train. At the same time, the second drive gear is connected to the PTO clutch of the PTO drive system via the second gear train arranged behind the first gear train to connect the main clutch and the PTO clutch. The input shaft and the main shaft provided with the main clutch and the PTO transmission shaft provided with the PTO clutch are arranged in parallel with each other by arranging them in the front-rear direction,
A power transmission device for a tractor, wherein a front end of the PTO transmission shaft is located rearward of the main clutch, and the main clutch and the PTO clutch are arranged so as to overlap each other in a vertical direction.