JPS646048B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tractor, especially a medium-sized tractor (approximately 40 PS).
Regarding the transmission of agricultural tractors.

Traditionally, this type of tractor has had an integral structure in which the engine block and transmission case are connected by a clutch housing to form a frame, but the height of the driver's seat is limited to a certain level due to reasons such as running stability. Therefore, the height of the step on which the driver rests his or her feet above the ground is kept below 600 mm. On the other hand, for workability, especially workability in rice fields, a minimum ground height of approximately 400mm is required;
Clutch housing is 150-200mm from the step surface
It was protruding upward to some extent. Furthermore, since the transmission case houses the main and auxiliary transmission gears,
These change levers protruded significantly upward in front of the driver's seat. As a result, when getting in and out of the driver's seat, the driver has to step over the clutch housing and change lever that protrude, which is extremely troublesome. Small women and girls were forced to perform difficult tasks. In addition, the driver had to put his feet on narrow steps divided into left and right sides, and his posture was fixed when operating the vehicle, resulting in great fatigue for the driver when driving for long periods of time.

Therefore, the present invention divides the transmission case into three parts, and the front transmission case contains the main transmission.
A PTO transmission is built in, and a plurality of shafts are arranged in the vertical direction, and an auxiliary transmission is built in the intermediate transmission case, and the plurality of shafts constituting the auxiliary transmission are arranged in the horizontal direction, and the front A predetermined shaft of the plurality of shafts in the intermediate transmission case is arranged in alignment with a shaft located below a main shaft interlocking with the engine crankshaft in the intermediate transmission case, and is positioned below an extension line of the main shaft. It is an object of the present invention to provide a tractor in which the upper surface of the intermediate transmission case is positioned so that the upper surface becomes a flat deck surface serving as a step surface, thereby eliminating the above-mentioned drawbacks.

Embodiments based on the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the agricultural tractor 1 has an engine block 5 supported by front wheels 2 together with a front chassis 3 at the front, and a rear transmission case 7 supported by rear wheels 6 at the rear. are placed. Further, a front transmission case 9 is fixed to the rear of the engine block 5, and the front transmission case 9 and the rear transmission case 7 are connected by an intermediate transmission case 10, so that each case is connected. It is constructed of a one-piece construction type in which the frame is made up of two pieces. Further, a driver's seat 11 is disposed on the rear transmission case 7, and an upper case 12 is disposed on the front transmission case 9, and the case 12 has a steering wheel 13 and a main transmission gear facing upward. A lever 15 and a PTO shift lever 16 are arranged.
Further, the intermediate transmission case 10 is configured to expand laterally, and its lower surface has a minimum ground height H.
At the same time, its upper surface is pressed down to the maximum step height h, forming a flat deck surface 10a constituting a step surface on which the driver's feet are placed. In the figure, 17 is a front wheel transmission shaft extending forward from the intermediate transmission case 10 for driving the front wheels 2, and 19 is a PTO shaft projecting rearward from the rear transmission case 7. As shown in FIG. 2, the front part of the front transmission case 9 is connected to the clutch chamber 9a.
Further, the rear part is a transmission gear chamber 9b, and a main clutch (not shown) is housed in the clutch chamber 9a, and a main shaft 20 is rotatably supported through the main clutch through the transmission gear chamber 17b. . Also,
The transmission gear chamber 9b includes a distribution shaft 21, and above and below the shaft 21, respectively, a running intermediate shaft 22 and a PTO intermediate shaft 2.
3 is rotatably supported, and the traveling intermediate shaft 22 is aligned with the main shaft 20 and arranged so as to be rotatable with respect to each other. Further, a gear 25 is fixed to the tip of the main shaft 20, and the gear 25 is always meshed with a gear 26 fixed to the distribution shaft 21. Also,
The distribution shaft 21 has four gears 27, 28, 29, 30 whose number of teeth decreases sequentially from the front to the rear.
are fixed, and the traveling intermediate shaft 22 and
The PTO intermediate shaft 23 has gears 31, 32, 33, 34 and 3 which are constantly meshed with each gear of the distribution shaft 21.
6, 37, 38, and 39 are each rotatably supported. Further, the traveling intermediate shaft 22 includes first and second gears 31, 32 and third and fourth gears 33, 34.
Between the selection clutches 41 and 42, the selection clutches 41 and 42 are fitted so that they can only slide freely.
is operated by the main shift lever 15. Similarly, on the PTO intermediate shaft 23, selection clutches 43 and 44 are fitted between the first and second gears 36, 37 and the third and fourth gears 38, 39, respectively, so that they can only slide freely. , the selection clutches 43 and 44 are operated by the PTO shift lever 16. Furthermore,
A gear 45 is fixed to the end of the traveling intermediate shaft 22, and the gear 45 is connected to a gear rotatably supported on the PTO intermediate shaft 23 via a gear 46 rotatably supported on the distribution shaft 21. It is connected to 47.

On the other hand, as shown in FIG. 4, the intermediate transmission case 10 rotatably supports a PTO transmission shaft 49 and a sleeve-shaped traveling transmission shaft 50 concentrically, and the transmission shafts 49, 50 A switching shaft 51 and an auxiliary transmission shaft 52 are arranged on the left and right sides, and a front wheel drive shaft 53 and an idler shaft 55 are arranged further below. The PTO transmission shaft 49 is connected to the PTO intermediate shaft 23 through a spline joint 56, and the traveling transmission shaft 50 is connected to the gear 47 through a traveling clutch 57. As shown in FIGS. 2 and 3, gears 59 and 60 are fixed to the traveling transmission shaft 50, and each of these gears 59 and 60 is a gear that is rotatably supported on the switching shaft 51. 61 or via an idler gear 62 rotatably supported by the idler shaft 55, the gear 63 is constantly meshed with the idler gear 63. Further, a selection clutch 64 is slidably supported on the switching shaft 51, and the selection clutch 64 can mesh with either one of the gears 61, 63.
Therefore, either forward or reverse rotation is transmitted to the switching shaft 51. Further, a gear 65 is fixed to the switching shaft 51, and an integral gear 69 consisting of a large gear 66 and a small gear 67 is rotatably supported. On the other hand, the PTO transmission shaft 49 has an integral gear 72 consisting of a large gear 70 and a small gear 71, and a small gear 73.
An integral gear 75 consisting of a large gear 74 and a gear 7
6 are rotatably supported, the large gear 70 is connected to the gear 65, the small gear 71 is connected to the large gear 66, and the large gear 7
4 are in constant mesh with the small gear 67. Further, a switching gear 79 consisting of a small gear 77 and a large gear 78 is fitted to the sub-transmission shaft 52 so as to be able to slide only.
1 and 73, and can be operated via a shifter 80 by an auxiliary transmission arm 81 disposed on the side of the intermediate case 10. Further, a gear 82 is fixed to the auxiliary transmission shaft 52, and the gear 82 is always meshed with the gear 76 from the side thereof. Further, the gear 76 is constantly meshed with a gear 83 which is rotatably fitted to the front wheel drive shaft 53 at the lower part thereof, and the differential pinion shaft which is rotatably supported by the rear transmission case 7 at the upper part thereof. It is constantly meshed with a gear 85 fixed to 84. The gear 83 can mesh with a clutch 86 that is slidably fitted onto the front wheel drive shaft 53, and the front wheel drive shaft 53 is connected to the front wheel transmission shaft 17 via a spline joint 87. The differential pinion shaft 84 is the differential gear 8
The shaft 84 is connected to the rear wheel 6 via a shaft 84, and a gear 90 is fixed in the middle of the shaft 84. Also,
A joint 91 is fixed to the rear end of the PTO transmission shaft 49, and further aligned with the shaft 49, the rear case 7
A PTO drive shaft 92 is rotatably supported. Further, a coupling hub 95 is supported on the PTO drive shaft 92 via a PTO clutch 93, and a gear 96 is supported on the hub 95 so as to be able to slide only. Joint 91 of transmission shaft 49 or gear 90 of pinion shaft 84
It can mesh with either one of the two. Furthermore, a gear 97 is formed on the PTO drive shaft 92.
7 is constantly meshed with a gear 99 fixed to the PTO shaft 19. In addition, the front transmission case 9
The respective distances L of the traveling intermediate shaft 22 and the PTO intermediate shaft 23 from the distribution shaft 21 which are arranged in the longitudinal direction, and the PTO transmission shaft 49 and the traveling transmission shaft 50 which are arranged laterally in the intermediate transmission case 10. The distances L between the switching shaft 51 and the auxiliary transmission shaft 52 from the rear transmission case 7, and the distances L between the differential pinion shaft 84 and the PTO drive shaft 92, which are vertically arranged in the rear transmission case 7, are set to be approximately equal to each other. has been done.

Since this embodiment has the above configuration, the rotation of the engine 5 is transmitted to the main shaft 20 via the main clutch in the front transmission case 9, and further transmitted to the distribution shaft 21 via the gears 25 and 26. and then gears 31 and 3 rotating at different speeds via gears 27, 28, 29, and 30, respectively.
2, 33, and 34. These gears 3
The rotation of any one of the gears 1 to 34 is transmitted to the traveling intermediate shaft 22 by engagement of the selection clutch 41 or 42 operated by the main shift lever 15, and the rotation of the intermediate shaft 22 is further transmitted to the gears 45 and 42. 46
is transmitted to gear 47 via. On the other hand, distribution axis 2
The rotation of the gears 27 to 30 on the PTO intermediate shaft 23 respectively rotates the gears 36, 37, 38, and 39 on the PTO intermediate shaft 23 at different speeds.
The rotation of any one of them is transmitted to the PTO intermediate shaft 23 by engagement of selection clutches 43 and 44 operated by the PTO speed change lever 16.

The rotation of the gear 47 is transmitted to the sleeve-shaped running transmission shaft 50 via the running clutch 57.
Furthermore, the gear 61 is connected to the gear 61 via the gear 59;
Rotation in different directions is transmitted to the gear 63 via the idler gear 62 and the rotation in either the forward or reverse direction is transmitted to the switching shaft 51 by the engagement of the selection clutch 64. Further, the rotation of the shaft 51 is transmitted through a gear 65 to an integral gear 72, and further to an integral gear 6.
9 to the integral gear 75, each being decelerated and transmitted. Then, on any one of the gears 70, 71, or 73 of these integral gears 72, 75,
Due to the switching operation by the sub-shift arm 81, the switching gear 79 that is slid through the shifter 80 is engaged, and a desired rotational speed is transmitted to the sub-shift shaft 52. That is, due to the meshing of the gears 70 and 77, the high speed is
Due to the meshing of gears 71 and 78, medium speed is achieved, and gear 7
Low speed can be obtained by meshing between 3 and 78. Further, the rotation of the auxiliary transmission shaft 52 is transmitted to the gear 76 via the gear 82, and further transmitted to the front wheel drive shaft 53 via the gear 83 and the clutch 86.
is transmitted to the differential pinion shaft 84 via. The rotation of the differential pinion shaft 84 is transmitted to the rear wheels 6 via the differential device 89, and the rotation of the front wheel drive shaft 53 is transmitted to the front wheels 2 via the spline joint 87 and the front wheel transmission shaft 17. 1
is run.

On the other hand, the rotation of the PTO intermediate shaft 23 is transmitted to the PTO transmission shaft 49 via the spline joint 56 and further to the joint 91. In addition, due to selective engagement with the joint 91 or the gear 90 as the gear 96 slides, the PTO transmission shaft 49 or the differential pinion shaft 8
4 is transmitted to the coupling hub 95, which in turn is transmitted to the PTO clutch 93 and the PTO drive shaft 9.
2 and gears 97 and 99 to the PTO shaft 19. That is, when the gear 96 meshes with the gear 90, a PTO output related to the running speed can be obtained, and when the gear 96 meshes with the joint 91, a PTO output that is not related to the running speed, so-called live
You can earn PTO. During the live PTO, keep the king clutch connected, and when driving, use the driving clutch 5.
7, the PTO is also activated by the PTO clutch 93.
They are each independently switched.

As explained above, according to the present invention, the transmission case is divided into three parts, and the intermediate transmission case 1 is divided into three parts.
0 has a built-in auxiliary transmission with the shafts 49, 50, 51, and 52 arranged laterally, so the vertical dimension of the intermediate transmission case 10 is made smaller and the lateral dimension is increased, so that the lowest ground Although the height H and step height h are kept the same as in the conventional case, a flat deck surface 10a can be secured on the upper surface of the intermediate transmission case 10 while maintaining sufficient strength, and the front transmission case 9 can have a flat deck surface 10a on the upper surface. , a plurality of shafts 20, 21, 22, 23 are arranged in the vertical direction, and the shaft in the intermediate case 10 is located at the level of the shaft 23 located below the main shaft 20, and the intermediate case 1
The flat deck surface on the upper surface of the driver's seat can be positioned below so as to become the step surface on which the driver rests his/her feet.
Since the front transmission gear 9 with built-in PTO transmissions 36 to 39, 43, and 44 is located,
The main gear shift lever 15 and the PTO gear shift lever 16 can be placed in front of the flat deck surface 10a, so there are no protrusions in the area where the driver's feet are positioned, making it easier for the driver to get on and off the vehicle, and improving the comfort of the driver. This means less fatigue even when driving for long periods of time. Furthermore, when the PTO transmission shaft 49 and the switching shaft 51 and the sub-transmission shaft 52 are disposed on the left and right sides of the shaft 49 in the center of the intermediate transmission case 10, the transmission arm 81 is placed on the side of the intermediate transmission case 10. The auxiliary transmission arm 81 and the like do not protrude onto the flat deck surface 10a of the intermediate transmission case 10, which becomes the step surface, and furthermore, the ease of getting on and off and the comfort of living can be improved. In addition, a front wheel drive shaft 53 is attached to the intermediate transmission case 10.
When installed, while maintaining the minimum ground height H,
The height of the case 10 can be increased, and sufficient strength can be maintained as a monolithic frame.

[Brief explanation of drawings]

FIG. 1 is a side view showing a tractor according to the present invention;
Figure 2 is a side view of the transmission part, Figure 3 is a developed plan sectional view of the intermediate transmission case part,
FIG. 4 is a longitudinal sectional view showing the relationship between the respective axes. DESCRIPTION OF SYMBOLS 1... Tractor, 7... Rear transmission case, 9... Front transmission case, 10... Intermediate transmission case, 10a... Flat deck surface, 31-34, 41, 42... Main transmission, 3
6-39, 43, 44...PTO transmission, 49
...PTO transmission shaft, 51...Switching shaft, 52...
Sub-transmission shaft, 53...Front wheel drive shaft, 66-75,7
7-79...Sub-transmission device.

Claims (1)

[Scope of Claims] 1. A tractor having an integral structure in which a front transmission case, an intermediate transmission case, and a rear transmission case are connected to form a frame, the front transmission case having a main transmission and a rear transmission case. PTO
A transmission is built in and a plurality of shafts are arranged in the vertical direction, a sub-transmission is built in the intermediate transmission case, and the plurality of shafts constituting the sub-transmission are arranged in the transverse direction, and the front part A predetermined shaft of the plurality of shafts in the intermediate transmission case is arranged in alignment with a shaft located below the main shaft that interlocks with the engine crankshaft in the transmission case, and is arranged below the extension line of the main shaft. What is claimed is: 1. A tractor, characterized in that the upper surface of the intermediate transmission case is located on the upper surface of the intermediate transmission case, and the upper surface is a flat deck surface serving as a step surface.