JPH05178103A - Transmission structure of tractor - Google Patents

Abstract

PURPOSE:To reduce the cost by sharing a main gear transmission case with the form of taking gear transmission as both main and auxiliary speed change mechanisms and the form of taking a static hydraulic continuously variable transmission. CONSTITUTION:Power input through a main clutch 2 is changed in speed by a main gear transmission mechanism 10 in a main gear transmission case and then taken out to the front. The changed power taken to the front is changed in speed by an auxiliary transmission mechanism 13 in a front gear transmission case 4 attached to the front of the main gear transmission case 3, and the output from the auxiliary gear transmission mechanism 13 is again returned to the main gear transmission case 3 to be transmitted to a wheel driving differential gear mechanism 16 of the rear of the main gear transmission case 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling transmission structure used for a tractor.

[0002]

2. Description of the Related Art As a transmission structure for traveling used in a tractor, a main transmission mechanism and an auxiliary transmission mechanism are both gear transmissions, and a main hydraulic transmission is a hydrostatic continuously variable transmission (HST). In many cases, the sub-transmission mechanism is used as a gear transmission.

[0003]

Conventionally, the transmission type gear transmission cases are completely different from each other, and the cost is increased because they are separately designed and manufactured. SUMMARY OF THE INVENTION It is an object of the present invention to provide a transmission section structure capable of forming both transmission types by sharing a gear transmission case.

[0004]

In order to achieve the above object, the present invention is configured so that power input through a main clutch is shifted by a main gear transmission mechanism in a main gear transmission case and then extracted forward. Then, the shifting power taken out forward is shifted by the auxiliary transmission mechanism inside the front gear transmission case attached to the front of the main gear transmission case, and the output from this auxiliary transmission mechanism is returned to the main gear transmission case again. The main gear transmission case is configured to be transmitted to the diff mechanism for driving the wheels.

[0005]

According to the structure of the present invention, in the type in which both the main and auxiliary transmission mechanisms are gear transmissions, for example, as shown in FIG. 1, the power input to the input shaft 8 via the main clutch 2 is decelerated by one gear. And transmits to the first shaft 9 and then the main gear transmission 10 shifts the speed to the second shaft 11.
Output of the gear is transmitted by the auxiliary gear transmission mechanism 13 in the front gear transmission case 4, the transmission output is transmitted to the bevel pinion shaft 15 which is the final transmission shaft, and the wheels of the differential case 5 connected to the rear portion of the main gear transmission case 3 are driven. The differential mechanism 16 for driving is driven. The power of the first shaft 9 is PTO.
P provided at the rear of the differential case 5 via the gear transmission mechanism 18
It is transmitted to the TO shaft 6. Further, in the type in which the hydrostatic continuously variable transmission is used for the main transmission mechanism, for example, as shown in FIG. 2, the input shaft (pump shaft) 2 of the hydrostatic continuously variable transmission 20 is used.
1 is installed at the axial center position of the input shaft 8 of the above type, and the output shaft (motor shaft) 2 of the hydrostatic continuously variable transmission 20.
2 is installed at the axial center position of the second shaft 11 in the above-mentioned form, and the auxiliary gear speed change mechanism 13 is provided between the output shaft 22 and the bevel pinion shaft 15. In this case, the PTO
The transmission system is constructed in the same manner as the above type. In other words, the transmission shaft axis is the same in both types, and the material of the main gear transmission case 3 is made common to perform the axial hole machining according to each type.

[0006]

Therefore, according to the present invention, the material of the gear transmission case, which has been designed and machined as a completely different specification, can be shared between the gear transmission type and the type using the hydrostatic continuously variable transmission. It has become easier and the cost can be reduced by using the mold for making the case.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a transmission portion of a tractor constructed in a gear transmission type. In the figure, 1 is an engine, 2 is a main clutch, 3 is a main gear transmission case, 4 is a front gear transmission case mounted on the front surface of the main gear transmission case 3, and 5 is connected to a rear end of the main gear transmission case 3. The differential case 6 is a PTO shaft projecting from the rear end of the differential case 5. The main clutch 2 is a wet multi-disc clutch, and is installed in front of the main gear mission case 3 in parallel with the front gear mission case 4. The power taken out through the main clutch 2 is input to the input shaft 8 of the main gear transmission case 3, then is decelerated by one gear and transmitted to the first shaft 9, and the main gear speed change mechanism 10 moves forward three gears. Reverse 1
The speed is changed in steps and transmitted to the second shaft 11. This second axis 1
The power of 1 is the third shaft 1 of the front gear transmission case 4.
2 is transmitted to the fourth shaft 14 by the auxiliary gear transmission mechanism 13. The fourth shaft 14 is inserted into the main gear transmission case 3 to become a bevel pinion shaft 15 which is a final transmission shaft, and the transmission power is transmitted to the rear wheel differential mechanism 16 provided in the differential case 5. In the case of a four-wheel drive type, the fourth shaft 14 is projected forward to serve as a front-wheel drive shaft. Further, a fifth shaft 17 is concentrically arranged behind the input shaft 8, and a PTO gear speed change mechanism 1 for performing two forward rotation speed changes between the fifth shaft 17 and the first shaft 9.
8 are configured. The output of the fifth shaft 17 is transmitted to the PTO shaft 6 via the sixth shaft 19 and the like. The PTO gear speed change mechanism 18 can drive the PTO shaft 6 in the reverse direction by directly connecting the fifth shaft 17 to the input shaft 8.

FIG. 2 shows a hydrostatic continuously variable transmission (HST).
Shows the structure of a power transmission section utilizing the above, in which the main gear transmission case 3 and the differential case 5 in the gear transmission type power transmission structure are used as they are or as a case material. In this case, the hydrostatic continuously variable transmission 20 which is the main transmission mechanism has a front surface of the main gear transmission case 3 so that its input shaft (pump shaft) 21 is located at the axial center position of the input shaft 8 of the above type. And the output shaft (motor shaft) 22 of the hydrostatic continuously variable transmission 20 is installed at the axial center position of the second shaft 11 in the above-mentioned type, and between the output shaft 22 and the bevel pinion shaft 15. An auxiliary gear speed change mechanism 13 is provided in. In this type, the main clutch 2 is formed as a dry single plate clutch at the rear of the engine 1. Further, the PTO transmission system is constructed in substantially the same manner as the above type.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a schematic diagram of the structure of a transmission unit configured in a gear transmission form.

FIG. 2 is a schematic diagram showing a structure of a transmission section of a type utilizing a hydrostatic continuously variable transmission (HST).

[Explanation of symbols]

 2 main clutch 3 main gear transmission case 4 front gear transmission case 10 main gear transmission 13 auxiliary gear transmission 16 differential mechanism

Claims (1)

[Claims] 1. A structure in which power input through a main clutch (2) is shifted forward by a main gear transmission mechanism (10) in a main gear transmission case (3) and then extracted forward, and is extracted forward. The speed change power is changed by the auxiliary gear speed change mechanism (13) in the front gear transmission case (4) attached to the front surface of the main gear transmission case (3), and the output from the auxiliary gear speed change mechanism (13) is changed. A transmission structure of a tractor configured to be returned to the main gear transmission case (3) and transmitted to a wheel drive differential mechanism (16) at the rear of the main gear transmission case (3).