JPH08502B2 - PTO shaft drive for tractor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a tractor for agriculture or the like, and more particularly to a transmission case with a rear PTO shaft and an intermediate PTO shaft.
The present invention relates to a PTO shaft drive device in a tractor having a TO shaft and a front PTO shaft.

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 incorporated in the mission case, and engine power input to the input shaft is transmitted to the final shaft through the transmission mechanism.
Wheels are driven by the final shaft.

The mission case is further equipped with a PTO shaft, and the input engine power is also transmitted to this PTO shaft, and the power is transmitted to the work machine connected to the tractor via the PTO shaft. But the rear PTO axis and the middle P
It has three PTO axes, a TO axis and a front PTO axis.
There is one in which each work machine connected to a rear portion, a middle portion and a front portion of a vehicle body is driven by a shaft.

The work machine connected to the front part of the vehicle body is, for example, a lawn mower (mower), and in this case, the work may be performed only by the lawn mower, or the lawn grass mowed by this lawn mower is transferred to the rear part of the vehicle body. It may be collected by a connected grass and grass collector (sweeper). In addition, a lawn mower may be further connected to the middle portion of the vehicle body, rough cutting may be performed by the front lawn mower, and then finishing may be performed by the middle lawn mower.

Problems to be Solved by the Invention As can be seen from the above, the front, middle, and rear PTO axes are used in an appropriate combination according to the type of work, so only the PTO axes used during work are used. It is desirable that the power be transmitted from the engine to improve the efficiency of use of the power. However, on the other hand, in order to realize this, it is inevitable that the drive structure of the PTO axis becomes complicated.

Therefore, the present invention is intended to obtain a small and simple PTO shaft drive device capable of easily switching modes of power transmission to the three PTO shafts.

Therefore, in the present invention, in the present invention, the rear PTO shaft, the intermediate PTO shaft, and the front PTO shaft for respectively driving the working machines mounted on the rear portion, the middle portion, and the front portion of the vehicle body. In a PTO shaft drive of a tractor equipped with, a PTO transmission shaft connected to the input shaft of the transmission case via a clutch is provided in the transmission case, and the rear PT is connected via the PTO transmission shaft.
Power is transmitted to the O-axis, intermediate PTO axis and front PTO axis.

According to the invention, the front, middle and rear PTO shafts are all driven from one PTO transmission shaft connected via a clutch to the input shaft driven by the engine,
The drive system is simple without the need for extra shafts or belts.

Also, by connecting and disconnecting the clutch, the PTO drive system can be shut off from the engine or connected to the engine at once, and since the PTO drive system and the travel drive system are independent of each other, The drive state is not affected by the running state of the tractor, and when the work machine is not used, the PTO drive system can be shut off from the engine to avoid loss of engine power due to idling of the shaft of the system. .

Further, on the PTO transmission shaft, by providing a power transmission switching device capable of selectively transmitting power to each PTO shaft,
A simple and compact device can switch the power transmission to the three PTO shafts in various combinations.

Practical Example FIG. 3 is an overall side view of a tractor 80 to which the present invention is applied. A front frame 82 is mounted on the front part of a body frame 81, and a rear wheel 83 is mounted on the rear part. Engine 84 on the upper front of single frame 81
Is mounted, and the output shaft of the engine 84 is a flywheel 8
5. Connected to the input shaft of the mission case 1 via the propeller shaft 86. A power transmission device, which will be described later, is built in the mission case 1. The engine power input to the input shaft is appropriately changed in speed through the power transmission device, and then transmitted to the rear wheel 28 and the front wheel drive shaft 87. Is output.

Also from mission case 1, front PTO shaft 70, middle P
Three PTO shafts, the TO shaft 41 and the rear PTO shaft 44, extend, and the engine power input to the input shaft is the PT of these.
It is also transmitted to the O-axis. Work machine drive axis for each PTO axis
The front work implement F, the intermediate work implement M, and the rear work implement R are connected via 70a, 41a, 44a. In the example shown,
The front work machine F and the intermediate work machine M are lawn mowers, and the rear work machine R is a lawn mower. The front work machine F roughly cuts high grass and the intermediate work machine M finishes and cuts the lawn. Use the work equipment to collect grass. Of course, the usage form of the tractor 80 is not limited to this, and various working machines are connected to all or a part of each PTO shaft 70, 41, 44 in various combinations, and each is used according to the purpose. You can do the work.

FIG. 2 is a system diagram of the power transmission device in the mission case 1 of the tractor 80. The main clutch case 2 is integrally attached to the front end of the mission case 1,
An input shaft 5 is pivotally supported on the front wall 1a of the mission case 1 and the main clutch case 2 via bearings 3 and 4, respectively.
The input shaft 5 is connected to the engine 84 via the propeller shaft 86 and the flywheel 85 as described above, and is constantly rotating during engine operation. A 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 mounted on the transmission case 1 via bearings 10 and 11.
Is rotatably supported on the front wall 1a and the intermediate wall 1b.
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.
Of the input bevel gear, and the rear wheel 28 is driven via the differential device 27. The final shaft 24 also drives a front wheel drive shaft 87 (FIG. 3) via a gear 29.

The above-mentioned power transmission path from the input shaft 5 to the final shaft 24 branched by the gear 6 constitutes a traveling drive system for driving 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 31 is attached to the input shaft 5 via a one-way clutch 30, and the PTO is connected through the gear 31.
The power to drive the shaft is extracted. One-way clutch 30
Allows torque transmission from the input shaft 5 to the gear 31, but the gear 31
Torque transmission from the input shaft 5 to the input shaft 5 is blocked. The gear 31 meshes with an intermediate gear 32a rotatably fitted on the main shaft 7, and an intermediate gear 32b integral with the intermediate gear 32a meshes with the gear 33. The gear 33 has bearings 34, 3 on the front wall 1a and the intermediate wall 1b.
5 is loosely fitted to the PTO transmission shaft 36 supported via 5, and the PTO
It is connected to the PTO transmission shaft 36 via a clutch 37.

A front PTO shaft 70 is arranged in parallel with the PTO transmission shaft 36, and a drive gear 71 fixed to the shaft 36 and a driven gear 72 fixed to the shaft 70.
And are in mesh. Separately from the front PTO shaft 70,
An intermediate PTO shaft 41 is arranged in parallel with the TO transmission shaft 36. Further, behind the PTO transmission shaft 36, coaxially with the shaft 36, the front end is rotatably supported at the rear end of the shaft 36, and the rear end is at the rear case.
25 rear PTO transmission shaft 39 pivotally mounted on the rear wall of 25 via bearing 38
Is provided.

The power transmission switching device S is provided at the rear end of the PTO transmission shaft 36.
Is provided. This switching device S comprises a selector gear 40 which is slidable in the axial direction.
By straddling the O transmission shaft 36 and the rear PTO transmission shaft 39, both shafts 36, 39 are connected. Selector gear
40 also slides in the axial direction so that the intermediate PTO shaft 4
It is adapted to be disengaged from the gear 42 attached to 1. The selector gear 40 does not mesh with the gear 42, and the rear PTO
The leftmost position that does not engage with the transmission shaft 39, the middle left position that engages with the gear 42 and does not engage with the rear PTO transmission shaft 39, the middle right position that engages with the gear 42 and also engages with the rear PTO transmission shaft 39 The position and the gear 42 can occupy the rightmost four positions which are not meshed with the rear PTO transmission shaft 39, and the rotation of the PTO transmission shaft 36 depends on these positions and only the front PTO shaft 70 is rotated. , Both front PTO shaft 70 and middle PTO shaft 41, front PTO shaft 70 and middle PTO
Axis 41 and all rear PTO transmission shafts 39 or front PTO shaft 70
And transmitted to both rear PTO transmission shaft 39.

The front PTO shaft 70 extends forward from the mission case 1 and is connected to the shaft via a universal joint through a working machine drive shaft 70a (Fig. 3) to a working machine F attached to the front part of the tractor vehicle body. Power is transmitted. Similarly, the intermediate PTO shaft 41 transmits power to the work machine M attached to the intermediate portion of the tractor vehicle body. Rear PTO transmission shaft 39 is gearbox 4
Is connected to the rear PTO shaft 44 via 3, and the rear PTO shaft 44 is
Power is transmitted to the working machine R mounted on the rear part of the tractor vehicle body.

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. 2 is a sectional view showing the structure of a part of the traveling drive system and a part of the PTO drive system more specifically, and the same reference numerals are given to the similar parts in FIGS. 1 and 2. Supplementing the above description with FIG. 2, 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 inserted between the clutch inner 51 and the clutch inner 51, and the pressure 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 a single unit is operated, the shaft 57 moves rearward (to the right in the drawing) via the differential mechanism 56 interlocked with the operating member, and the lifter plate 54 also moves with it. The pressure contact 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.

A front PTO shaft 70 is connected to the PTO transmission shaft 36 via gears 71 and 72. The rear PTO transmission shaft 39 is located at the rear end of the PTO transmission shaft 36.
The front end of is rotatably fitted through a needle bearing 66,
Splines 67a and 67b are formed on the peripheral surfaces of the PTO transmission shaft 36 and the rear PTO transmission shaft 39 having the same diameter. The selector gear 40 is slidably engaged with these splines 67a, 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 directly connected to the shaft 36 via the gears 71 and 72. Is transmitted only to the front PTO shaft 70 and the intermediate PTO shaft 41, and when the selector gear 40 is engaged across the splines 67a and 67b and meshes with the intermediate gear 68 as shown by a broken line 40a, The rotation of the PTO transmission shaft 36 is transmitted to all of the front PTO shaft 70, the middle PTO shaft 41 and the rear PTO transmission shaft 39. When the selector gear 4 is further displaced rearward and disengages from the intermediate gear 68 and occupies a position where the selector gear 4 engages with the spline 67a and the spline 67b, the PTO transmission shaft 36 rotates. It is transmitted only to the front PTO shaft 70 and the rear PTO transmission shaft 39.

When the selector gear 40 slides to the foremost position and disengages from the intermediate gear 68, as shown by the broken line 40C, the rotation of the PT transmission shaft 36 is transmitted only to the front PTO shaft 70.

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 travel drive system and the power transmission via the PTO drive system are performed independently of each other, and the drive state of the work machine by the PTO shaft is not affected by the traveling state of the tractor. The PTO drive system can be completely disconnected from the engine when not in use.

Furthermore, the power transmission switching device S having an extremely simple structure in which the selector gear 40 is spline-engaged slidably over the PTO transmission shaft 36 and the rear PTO transmission shaft 39 allows transmission of engine power only to the front PTO shaft 70. , Front PTO shaft 70 and intermediate PTO shaft 41, front PTO shaft 70 and intermediate PTO shaft 41 and rear PTO transmission shaft 39, front PTO shaft 70 and rear PTO transmission shaft 39 can be switched and set. Therefore, it is possible to efficiently cope with various usage forms of the tractor.

EFFECTS OF THE INVENTION As is apparent from the above, according to the present invention, the P in the tractor having the three front, middle and rear PTO shafts is provided.
The TO-axis drive system can be simplified and simplified. Also each
The drive state of the PTO shaft is not affected by the running state of the tractor, and the PTO shaft drive system can be shut off from the engine to prevent loss of engine power when the work machine is not used. The power transmission switching device with a simpler structure can switch and set the engine power transmission to each PTO shaft in various ways, and efficiently correspond to various usage forms of the tractor.

[Brief description of drawings]

FIG. 1 is a system diagram showing a power transmission device according to the present invention, and FIG.
FIG. 1 is a sectional view specifically showing a part of the structure of the power transmission device of FIG. 1, and FIG. 3 is an overall side view of a tractor to which the present invention is applied. 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, 31 …… gear, 32 ...... Intermediate gear, 33 ...... Gear, 3
4,35 …… 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, 4
4 …… 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, 58,59,60 …… Needle bearing, 61 …… Clutch inner, 62 …… Clutch outer, 63 …… Clutch plate, 64 ……
Working member, 65 ... Oil passage, 66 ... Needle bearing, 67 ...
Spline, 68 …… Intermediate gear, 70 …… Front PTO shaft, 71, 7
2 …… Gear, 80 …… Tractor, 81 …… Body frame, 82
...... Front wheel, 83 …… Rear wheel, 84 …… Engine, 85 …… Flywheel, 86 …… Propeller shaft, 87 …… Front wheel drive shaft.

Claims (2)

[Claims] 1. A rear PTO shaft and an intermediate P for driving respective working machines mounted on a rear portion, a middle portion and a front portion of a vehicle body.
In a PTO shaft drive device for a tractor having a TO shaft and a front PTO shaft, a PTO transmission shaft connected to the input shaft of the mission case via a clutch is provided in the mission case, A tractor PTO shaft drive device that transmits power to a rear PTO shaft, an intermediate PTO shaft, and a front PTO shaft. 2. A tractor PTO according to claim 1, wherein a power transmission switching device capable of selectively transmitting power to each of the PTO shafts is provided on the PTO transmission shaft.
Axle drive.