JPH0475524A - Transmission structure of tractor - Google Patents

Abstract

PURPOSE:To lower center of gravity of a transmission by arranging an abrasion type variable - speed drive mechanism below an input pulley of a belt transmission mechanism and arranging a wheel shaft of a deaf mechanism behind a main shaft of the abrasion type variable - speed drive mechanism and arranging a middle shaft between the main shaft and the wheel shaft. CONSTITUTION:A transmission device A is composed of an abrasion type variable - speed mechanism C for variably changing speed of rotation input by a belt transmission mechanism 7, a reversibly rotatable changeover mechanism D capable of changing rotating direction of output of the variable - speed drive mechanism C and a deaf mechanism E. The abrasion type variable mechanism C is arranged under the input pulley 9 of the belt transmission mechanism 7 and the wheel shaft 32 of the deaf mechanism E is arranged behind the main shaft 14 in the abrasion type variable - speed drive mechanism C and a middle shaft 25 constituting the reversibly rotatable changeover mechanism D together with the main shaft 14 is arranged parallel to the main shaft 14. Thus, the above-mentioned structure can be contributed to lowering of the center of gravity as whole the machine body can stably be mowed even on an inclined ground and mowing operation on a steeply inclined ground is made possible.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission structure for a tractor mainly used as a mid-mounted lawn mower, and more specifically, to a transmission structure for a tractor used as a mid-mounted lawn mower. The present invention relates to a transmission structure for a tractor in which a belt transmission mechanism is used to interlock and connect a driving transmission device mounted on the rear part of the machine body.

[Conventional technology]

The transmission structure of this type of tractor is
As shown in Publication No. 2326, the rotation from the engine through belt transmission is input to the H3T (hydrostatic continuously variable transmission), and the output of this H3T is input to the driving transmission to drive the rear wheels. It was configured to be driven, and the H3T was placed above the human-powered boot.

[Problem to be solved by the invention]

According to the prior art, the H3T, which is relatively heavy, is disposed above the transmission belt, so the center of gravity of the entire transmission device including the forward/reverse switching mechanism, etc., and by extension the center of gravity of the tractor, are This had a considerable influence on the rise in prices.

Further, in work areas with many ups and downs such as golf courses, mowing work on slopes is often performed, so it is desirable to lower the center of gravity as much as possible.

An object of the present invention is to realize a lower center of gravity of the transmission device by devising the structure of the transmission device.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a friction-type continuously variable transmission mechanism that continuously changes the speed of rotation inputted by a belt transmission mechanism, in the tractor transmission structure described at the beginning. It is composed of a forward/reverse switching mechanism capable of switching the rotational direction of the output of the transmission mechanism, and a differential mechanism, and the friction type continuously variable transmission mechanism is arranged below the input boot of the belt transmission mechanism, and the friction type continuously variable transmission mechanism is arranged below the input boot of the belt transmission mechanism. The axle of the differential mechanism is disposed behind the left-right main shaft of the transmission mechanism, and between these main shafts and the axle, an intermediate shaft that constitutes the forward/reverse switching mechanism with the main shaft is arranged parallel to the main shaft. The characteristic configuration is that the

[For production]

To lower the center of gravity of the transmission, H3 should be protruded upwards.
One possible solution would be to place the T under the transmission belt, that is, under the input boot. However, the H8T requires a cooling fan, and it is not desirable for safety to have such a rotating body close to the underbelly of the aircraft where the mower is located, so it is difficult to place the H3T below the input boob. .

In contrast, the friction type continuously variable transmission mechanism, which has a continuously variable speed function like the H3T, does not have a rotating body such as a cooling fan outside the case, so the friction type continuously variable transmission mechanism is also placed below the input boolean. Even if it is positioned, there will be no problems such as grass clippings or foreign objects getting tangled in the cooling fan like in the case of the H3T.

Since the intermediate shaft constituting the forward/reverse switching mechanism is also disposed between the main shaft and the axle, the entire transmission device can be disposed below the driven boot.

〔Effect of the invention〕

As a result, the low placement of the heavy transmission equipment contributes to lowering the center of gravity of the entire machine, making it possible to stably mow lawns even on slopes, and even on steeper slopes. We were able to provide a transmission device suitable for a mid-mount mower tractor.

〔Example〕

Figure 3 shows a fuselage (3) equipped with a longitudinal axis engine (1) at the front, a control unit (2) located at the center, and a transmission (A) at the rear. ), (5) shows a lawn mowing tractor configured to be movable and having a mower (6) suspended from the lower abdomen of the machine. Transmission device t (
A) and mower (6) are both belt transmission mechanisms (7)
, (8) is configured to input the power of the engine (1).

Next, the transmission device (A) will be explained.

As shown in Fig. 1, the transmission device (A) includes a power input section (B) that inputs the power of the engine (1) through a belt transmission mechanism (7), and a friction type stepless transmission that continuously changes the speed of the input power. Transmission mechanism (hereinafter abbreviated as CVT) (C), this CV
T (C) It is configured to include a forward/reverse switching mechanism (D) that can switch the direction of rotation of the driving power after passing, a differential mechanism (E), and the like.

The power input section (B) has a vertical shaft (
10) and the input rotating body (
11) is configured by interlocking the input rotating body (
The shaft portion (12) of 11) is extended and protrudes outside the transmission case (13) to form a PTO shaft (F).

The CVT has an output shaft (14) around the output shaft (14).
) is provided with a plurality of rotatable taper cones (15) that are driven to revolve around the axis of the output shaft (14) by an input rotating body (11) that is arranged concentrically with the input rotating body (11), and these taper cones (15) An output rotating body (16) that is driven and rotated by contact with the output shaft (14) is attached to the output shaft (14), and a transmission member (17) that is shiftable in the axial direction is provided across the tapered cone (15). ing. The tapered cone (15) is in pressure contact with the output rotating body (16) which is biased by the cam mechanism (18), and this reaction force is received by the disk-shaped cone support (19), and the input rotating body ( 11) and an inner frame (20) connected to this outer frame (20).
1) forms a carrier (22), and supports the taper cone (15) via a support shaft (23) so as to be freely rotatable.

The forward/reverse switching mechanism (D) is configured to span the output shaft (14) and an intermediate shaft (25) provided with a brake device (24) at one end. That is, the drive gear (26) of the output shaft (14), the drive sprocket (27), and the intermediate shaft (2
5) driven gear (28) and driven sprocket (29),
The chain (30) reveals forward and reverse rotation directions, and the shift rotary tool (31) selects the rotation direction of the intermediate shaft (25).

The differential mechanism (E) fits the left and right axles (32), (32) inside a differential carrier (37), and also links the differential carrier (37) to the intermediate shaft (25) by a chain mechanism (33). It is connected.

As shown in Figure 2, the output shaft (14
), the intermediate shaft (25), and the axle (32) are all oriented leftward and rightward, and an entryway (9) is disposed above the transmission case (13) that houses these shafts.

Note that (34) is the operating shaft of the transmission member (17), and (35) is the operating shaft of the shift rotary tool (31).

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the transmission structure for a tractor according to the present invention, and FIG. 1 is a developed sectional view showing the structure, FIG. 2 is a side view of the transmission, and FIG. 3 is a side view of the lawn tractor. (1)...Engine, (7)...Belt transmission mechanism, (9)...Input cabooly, (14)
...Main shaft, (25) ...Intermediate shaft, (3
2)...Axle, (A)...Transmission device,
(C)...Friction type continuously variable transmission mechanism, (D)...
...Forward/reverse switching mechanism, (E)...Differential mechanism.

Claims (1)

[Claims] A tractor transmission structure in which a vertical shaft type engine (1) mounted on the front part of the machine body and a traveling transmission device (A) mounted on the rear part of the machine body are interlocked and connected by a belt transmission mechanism (7). The transmission device (A) includes a friction type continuously variable transmission mechanism (C) that continuously changes the rotation input by a belt transmission mechanism (7), and an output of the continuously variable transmission mechanism (C). It is composed of a forward/reverse switching mechanism (D) capable of switching the direction of rotation, and a differential mechanism (E), and the friction type continuously variable transmission mechanism (C) is located below the input pulley (9) in the belt transmission mechanism (7). The axle (32) of the differential mechanism (E) is arranged behind the left-right-oriented main shaft (14) of the friction type continuously variable transmission mechanism (C), and
Between the main shaft (14) and the axle (32), an intermediate shaft (25), which together with the main shaft (14) constitutes the forward/reverse switching mechanism (D), is arranged parallel to the main shaft (14). The transmission structure of a certain tractor.