JPH0649421B2 - Agricultural tractor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an agricultural tractor, and more particularly, to an improvement of a mission case incorporating a gear speed change mechanism for traveling and a gear speed change mechanism for driving an external power take-off shaft. .

[Conventional technology]

Conventionally, there are many agricultural tractors provided with two types of gear transmissions as described above, in which two types of gear transmissions are arranged in the front-rear direction, and are disclosed in JP-A-59-190564. There is also one in which two types of gear transmissions are arranged in the vertical direction.

[Problems to be Solved by the Invention]

However, as in the conventional example, when two types of gear transmissions are arranged vertically, this hinders downsizing of the transmission case in the vertical direction, and two types of gear transmissions are arranged in the front-rear direction. However, there is room for improvement because it hinders miniaturization of the mission case in the front-rear direction.

An object of the present invention is to reduce the size in the up-down direction and the front-rear direction by rationally modifying a mission case that internally houses a gear speed change mechanism for traveling and a gear speed change mechanism for driving an external power take-off shaft.

[Means for Solving the Problems]

A feature of the present invention is to provide a continuously variable transmission having a direct output system that outputs the power from the input shaft as it is and a shift output system that continuously outputs the power from the input shaft by continuously shifting the power. A power transmission system is formed to transmit power from one of the output systems to a gear transmission mechanism for traveling and to transmit power from the other to a gear transmission mechanism for driving an external power take-off shaft. The gear shift mechanism for driving the external power take-off shaft is mounted inside the mission case in parallel with each other in the left-right direction, and its operation and effect are as follows.

[Action]

According to the above feature, the gear shift mechanism for traveling and the gear shift mechanism for driving the external power take-off shaft can be arranged in parallel with each other, so that the vertical dimension of the transmission case can be shortened and the forward and backward directions can be reduced. The size can be shortened,
Further, the power from the output system of the continuously variable transmission is transmitted to the gear shifting mechanism for traveling and the gear shifting mechanism for driving the external power take-off shaft, so that the traveling speed can be continuously varied by effectively utilizing the combination. Alternatively, the driving speed of the external power take-off shaft can be continuously varied, and the ratio of the output system from the continuously variable transmission can be rationalized to make the arrangement of the gear transmission mechanism reasonably possible.

〔The invention's effect〕

Therefore, the agricultural tractor in which the transmission case is downsized in the up-down direction and the front-rear direction is configured by modifying the arrangement of the gear transmission mechanism.

In particular, the present invention also has the effect of increasing the degree of freedom of arrangement of the gear transmission system and the variety of transmission speeds by rational combination of the transmission case and the continuously variable transmission.

〔Example〕

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

As shown in FIG. 3, a clutch housing (2) is connected to the rear surface of the engine (1) at the front of the vehicle body, and the engine (1), the clutch housing (2) and a pair of left and right frames (3), (3). The hydraulic non-transmission device (4) and the mission case (5) are provided in a state of being connected via the, and the power from the transmission case (5) penetrates the front surface of the continuously variable transmission (4). Output shaft (6)
To the rear wheels (9) via the output shafts (8), (8) on the left and right sides of the mission case (5) and the power from the mission case (5). The power from the transmission system and the mission case (5) is taken from the external power take-off shaft (10) on the rear surface of the mission case (5) (hereinafter abbreviated as PTO shaft).
The driver's seat (11) is formed above the mission case (5) and the step (12) is formed above the pair of left and right frames (3) and (3) to form an agricultural tractor. ing.

As shown in FIGS. 1 and 2, the transmission case (5) has a gear shift mechanism (A) for traveling and a gear shift mechanism for driving the PTO shaft (10) so as to reduce the vertical and front-rear dimensions.
(B) and left and right are arranged in parallel.

That is, in the continuously variable transmission (4), the power of the input shaft (13) to which the power from the clutch housing (2) is transmitted (the output system is directly formed at the end of this shaft on the transmission case side) Variable-capacity hydraulic pump (4P) driven by, and hydraulic motor (4M) driven by pressure oil supply from the hydraulic pump (4P)
And the gear shifting mechanism (A) for traveling is a hydraulic motor.
The two gears (1) provided on the second shaft (15) that receives the power of the first shaft (14) (an example of the variable speed output system) from which the power from the
6) and (16) and the shift gear (18) provided on the third shaft (17), and the driving power is from the rear end of the third shaft (17) to the differential device (19) for the rear wheels, And transmitted to the output shaft (6).

Further, the gear transmission mechanism (B) for driving the PTO shaft (10) includes two gears (20), (20) provided on the input shaft (13) and a shift gear (22) provided on the fourth shaft (21). ) And the power is transmitted from the fourth shaft (21) to the PTO shaft (10) via the fifth shaft (23).

[Another embodiment]

The present invention may be applied to, for example, an agricultural tractor having a structure that does not use a frame, other than the above embodiments.

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

[Brief description of drawings]

The drawings show an embodiment of an agricultural tractor according to the present invention.
FIG. 2 is a diagram showing the transmission system of the mission case, FIG. 2 is a diagram showing the positional relationship of the shafts of the transmission system of the mission case, and FIG.
The figure is an overall side view of the agricultural tractor. (4) …… continuously variable transmission, (5) …… mission case, (10)
...... External power take-off shaft, (13) …… Input shaft, (A) …… Gear speed change mechanism for traveling, (B) …… Gear speed change mechanism for driving external power take-off shaft.

Claims (1)

[Claims] 1. A continuously variable transmission having a direct output system for directly outputting power from an input shaft (13) and a variable speed output system for steplessly shifting and outputting power from the input shaft (13). 4), the power from one of these output systems is transmitted to the gear shift mechanism for running (A), and the power from the other is taken out from the external power take-off shaft (10) the gear shift mechanism for driving (B). To form a transmission system that transmits the power transmission to the transmission case, and the gear transmission mechanism (A) for traveling and the gear transmission mechanism (B) for driving the external power take-off shaft (10) are installed side by side in the transmission case (5). An agricultural tractor.