JP3002385B2 - Transmission structure of tractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates, on the transmission structure of the tractor equipped with a mode A between the front and rear wheels.

[0002]

2. Description of the Related Art As a transmission structure of the tractor, a main transmission shaft geared to a main clutch output shaft is positioned below the main clutch output shaft and supported by a main clutch case. And a hydrostatic stepless transmission in which a hydraulic pump is positioned at a lower position and a hydraulic motor is positioned at a higher position. The input shaft of the hydraulic pump is connected to the main transmission shaft in an interlocked manner, and extends forward from the transmission case. A front-wheel drive shaft and a front-wheel drive shaft arranged in a front-rear direction below the engine are linked to each other via a pair of universal joints and a drive shaft, and a mid-mount type working device is provided at a lower portion of the transmission case. Is known which has a mid-PTO shaft for driving the motor. The above-described configuration is for arranging the main transmission shaft for transmitting the engine output to the hydrostatic continuously variable transmission at a low level to reduce the operation steps and to flatten the horizontal direction. Since the main transmission shaft arranged at the position was located at the center of the left and right of the vehicle body, the front wheel drive shaft arranged forward and backward below the engine was arranged below the main transmission shaft, and the rear end of the front wheel drive shaft and the transmission shaft The universal joint connecting the shaft and the shaft does not interfere with the main transmission shaft.

[0003]

As a result, the position of the universal joint connecting the rear end of the front wheel drive shaft and the transmission shaft is low, and when the mower is provided as a mid-mount type working device, the upper surface of the mower deck is not provided. The input bevel gear case protruding near the left and right centers of the motor will approach the transmission shaft and universal joint to the front wheel drive shaft when the mower rises, and it will not be possible to secure a sufficient height of the mower, raising the mower There was a risk that the mower would be damaged by contact with the ridge on the ground when traveling on an ups and downs. The present invention has been made in view of such a point, and it is possible to avoid interference between the input gear case and the front wheel transmission system when the mower is raised by rational improvement of the transmission structure, and The purpose is to ensure a sufficient ascent height.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is characterized in that an engine is disposed at a front portion of a vehicle body and a transmission case is disposed at a rear portion of the vehicle body. Equipped with a mower in the space below the vehicle body, the main clutch case located at the rear end of the engine,
The main transmission shaft geared to the main clutch output shaft is supported at a position below the main clutch output shaft, and a hydrostatic pump is located at the front of the transmission case with the hydraulic pump at the bottom and the hydraulic motor at the top. A step transmission is connected, an input shaft of the hydraulic pump and a main transmission shaft are interlockingly connected, and power is transmitted to a front axle case via a front wheel transmission shaft extending forward from a transmission case, and In the transmission structure of a tractor in which the mower can be driven by a mid-PTO shaft provided at the lower part of the transmission case, the front wheel drive shaft linked to the front axle case is supported in the front-rear direction below the engine. In addition, the front wheel drive shaft and the front wheel transmission shaft are interlocked via a universal joint, and the main transmission shaft and the front wheel drive shaft are arranged side by side with respect to the left and right center of the vehicle body and are arranged in parallel. It is also advantageous if the mid-PTO shaft is shaft-linked to a mower input bevel gear case which can be raised and lowered between the front and rear wheels.

[0005]

According to the above construction, the main drive shaft and the front wheel drive shaft are arranged in a right and left direction with respect to the left and right center of the fuselage and are arranged in parallel, so that the front wheel drive shaft is disposed below the main drive shaft. the high position the front wheel drive shaft with and laterally to <br/> offset can be deployed, as a result, the universal joint and the transmission of the transmission system of the input bevel gear case of elevated mower to the front wheels drive shaft It becomes easy to displace the vehicle laterally without interfering with the shaft, and it is possible to secure a large mower lift.

[0006]

As described above, according to the present invention, the height of the mower can be largely secured without changing the transmission function by a simple improvement simply by changing the installation positions of the main transmission shaft and the front wheel drive shaft. As a result, it is possible to prevent the occurrence of such a problem that the mower comes into contact with the ridge on the ground when traveling on an uneven ground.

[0007]

FIG. 1 shows a riding mower in which a tractor A is equipped with a mid-mount type mower M. FIG. In the tractor A, the main clutch case 2 is directly connected to the rear end of the engine 1 at the front of the vehicle body, and the main clutch case 2 and the transmission case 3 at the rear of the vehicle body are connected by a housing 4 having a sheet metal structure. A front axle case 6 supporting the front wheels 5 is supported below the front frame 4, a rear wheel 7 is supported on the transmission case 3, and a steering wheel 8 for steering the front wheels is provided near the rear of the main clutch case 2. And a driver's seat 9 is arranged above the transmission case 3, and a pair of left and right lower links for connecting a rear working device which is raised and lowered by a hydraulically driven lift arm 10 is provided at the rear of the transmission case 3. 11 is attached.

At the rear of the main clutch case 2, a gear case portion 2a is integrally formed. On the gear case portion 2a, a main transmission shaft 13 geared to the main clutch output shaft 12 is provided below the main clutch output shaft 12. It is positioned and supported. A hydrostatic stepless transmission (HST) 14 having a hydraulic pump positioned lower and a hydraulic motor positioned higher is connected to a front portion of the transmission case 3, and an input shaft 14a of the hydraulic pump and the main transmission shaft are connected. 13 are linked by a transmission shaft 15.

A transmission mechanism for further shifting the transmission output from the hydraulic motor is provided in the transmission case 3, and a front wheel transmission shaft driven in synchronization with the rear wheel 7 is provided at the front of the transmission case 3. 16 is extended forward. A front wheel drive shaft 17 interlockingly connected to the front axle case 6 is supported below the engine 1 in the front-rear direction. The front wheel drive shaft 17 and the front wheel transmission shaft 16 are connected to a pair of universal joints 18 and a transmission. A front wheel drive system is constituted by interlocking connection via a shaft 19. Then, the main transmission shaft 13 and the front wheel drive shaft 17 are disposed so as to be divided left and right with respect to the left and right center of the fuselage. As a result, as shown in FIG. The parts are arranged side by side.

A swing arm 20 having a front end connected and supporting the mower M is provided at a lower portion of the transmission case 3 so as to be vertically swingable about a fulcrum p. This swing arm 20 is connected to a rod 21
Lifting arm 22 suspended and supported via
Further, the lifting arm 22 is connected to the lower link 11.
Are mechanically linked via an operation link 23 and a rod 24, so that the swing arm 20 is swung with the elevating operation of the lower link 11, and the mower M is moved up and down.

As shown in FIG. 3, the mower M is constructed so that three blades 26 mounted on a deck 25 are driven to rotate in a horizontal direction to cut grass and discharge the grass through a discharge port 27 at the right end of the deck. Power is transmitted from a mid-PTO shaft 29 provided at the lower portion of the transmission case 3 to an input shaft 28a of an input bevel gear case 28 protruding from the upper surface of the deck, and is converted into vertical rotation by the input bevel gear case 28. Then, the central blade 26 is driven, and power is transmitted to the left and right blades 26 by the transmission belt 30. When the mower M is lifted, the mower M is provided so as to be slightly displaced from the left and right center of the vehicle body so that the input bevel gear case 28 does not interfere with the transmission shaft 19 of the front wheel transmission system (see FIG. 5).

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the accompanying drawings.

[Brief description of the drawings]

Fig. 1 Mid-mounted riding lawn mower using a tractor

FIG. 2 is a side view of a main part showing a mower raised state.

FIG. 3 is a plan view of the mower.

FIG. 4 is a schematic side view of a transmission system.

FIG. 5 is a rear view showing the input part of the raised mower.

[Description of Signs] 1 Engine 2 Main clutch case 3 Transmission case 12 Main clutch output shaft 13 Main transmission shaft 14 Hydrostatic stepless transmission 14a Input shaft 16 Front wheel transmission shaft 17 Front wheel drive shaft 18 Universal joint 28 Input bevel gear case 29 Mid PTO shaft M Mower

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60K 17/10 A01B 71/00 A01D 34/76 B60K 17/04

Claims (2)

(57) [Claims] An engine (1) is provided at a front portion of a vehicle body and a vehicle
Mission case (3) is placed at the back of the body
And the space below the vehicle between the front and rear wheels (5) and (7).
A main clutch case, which is provided with a mower (M) between the engine and the rear end of the engine (1)
Gear (12), geared to the main clutch output shaft (12)
The main transmission shaft (13) is connected to the main clutch output shaft (12).
Ri is supported by positioning downward, the hydraulic pump to the lower the front portion of the transmission case (3), connecting the static was positioned a hydraulic motor to the upper hydraulic stepless transmission (14), the hydraulic pump Input shaft (14
a) and the main transmission shaft (13) in an interlocking manner, and a front wheel transmission shaft (1) extending forward from the transmission case (3).
Cormorant by transmitting the power to the axle case (6) before through 6)
And equipped at the bottom of the transmission case (3)
The mower (M) can be driven by the mid PTO shaft (29)
In the transmission structure of a tractor , the front wheel drive shaft (17) interlockingly connected to the front axle case (6)
And was supported towards the front-rear direction below the engine (1), axially interlocked via the front-wheel drive shaft (17) and the front wheel transmission shaft (16) and a universal joint (18), said main transmission The shaft (13) and the front wheel drive shaft (17)
Distribute left and right to the left and right center of the body and deploy in parallel
Transmission structure of the belt tractor. Wherein said mid-PTO shaft (29), the front
The transmission structure of a tractor according to claim 1, wherein the power transmission structure of the tractor is axially interlocked with an input bevel gear case (28) of a mower (M) provided between the wheel (5) and the rear wheel (7) so as to be able to move up and down.