JP2585484B2 - Work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle such as a tractor or a lawn mower provided with a hydrostatic stepless transmission for traveling speed change.

[0002]

2. Description of the Related Art Hydrostatic continuously variable transmissions (Hydro S)
The static power transmission (hereinafter abbreviated as HST) is generally directly connected to the input-side wall surface of the gear transmission case. The HST sequentially sends out pressure oil from a large number of pump-side plungers and sequentially operates a large number of motor-side plungers with the pressure oil to obtain a rotational output. This is likely to occur, and this is transmitted to the vehicle body via the gear transmission case, which may deteriorate the driving environment. Therefore, it has been considered that a vibration isolating member such as a vibration isolating rubber is interposed in a connecting portion between the HST case and the gear transmission case.

[0003]

However, the mounting positions of the mounting portions such as bolt holes provided in the HST case are as follows.
Since the position is determined by the shape and dimensions of the case, the position is not always suitable for vibration isolation. or,
If the mounting portion of the case is provided at a position suitable for improving the vibration isolation effect, the specification of the case itself must be changed, which increases the cost. The present invention has been made in view of such circumstances, and has as its object to enable an HST to be attached to a gear transmission case with a high anti-vibration effect without changing the specifications of the HST case.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a gear transmission case in which an intermediate mounting member is mounted via a vibration isolating member, and a hydrostatic stepless transmission is mounted on the intermediate mounting member. Are rigidly connected, and the output shaft of the hydrostatic continuously variable transmission and the input shaft of the gear transmission case are connected by a vibration-absorbing type shaft coupling.

[0005]

According to the above configuration, the vibration generated in the HST is:
It is absorbed by the vibration isolating member and transmission to the gear transmission case is suppressed. In this case, since the vibration isolating member is interposed between the gear mounting case and the intermediate mounting member rigidly connecting the HST case, it is necessary to support the vibration isolating member at a location different from the mounting portion of the HST case. Can be.

[0006]

Therefore, according to the present invention, it is easy to install a required number of vibration isolating members at a position where the vibration isolating effect is high, without modifying the mounting position of the HST case. As a result, the HST can be mounted on the gear transmission case while effectively supporting the HST at a relatively low cost.

[0007]

FIG. 5 shows an agricultural tractor as an example of a working vehicle to which the present invention is applied. This agricultural tractor
A front frame 5 protrudes forward from the engine 1 to form a vehicle body by connecting an engine 1 at the front of the vehicle body, a main clutch case 2 directly connected thereto, and a gear transmission case 3 at the rear of the vehicle body with a hollow sheet metal housing 4. To the front wheel 6,
Further, the vehicle has a vehicle body structure in which a rear wheel 7 is supported by a gear transmission case 3. An HST (hydrostatic continuously variable transmission) 8 attached to the gear transmission case 3 is accommodated in the rear portion of the housing 4, and the power input from the main clutch case 2 to the HST 8 via the transmission shaft 9 is not applied. The gears are switched to the forward and reverse rotations and input to the gear transmission case 3, the gears are further appropriately shifted to drive the rear wheels 7, and the front wheel transmission shaft 10 linked to the rear wheel drive system is led out forward. The front wheel 6 is configured to be driven synchronously. As shown in FIG. 2 and FIG.
The case 11 of T8 is rigidly connected to a pair of left and right intermediate mounting members 12 with a plurality of bolts 13 and the intermediate mounting members 12 are provided with spacer collars 14 at a plurality of locations on the front surface of the gear transmission case 3 as shown in FIG. It is attached in a vibration-proof manner by bolts 16 through which a vibration-proof member 15 made of a rubber collar is inserted. As described above, the HST 8 is supported by the gear transmission case 3 in a vibration-proof manner.
By being surrounded by the housing 4, the transmission of the drive noise of the HST 8 to the outside of the vehicle is suppressed.

Along with supporting the HST 8 in anti-vibration, the connection between the front end of the input shaft (pump shaft) 17 of the HST 8 and the transmission shaft 9, the rear end of the input shaft 17 and the PTO of the gear transmission case 3. A coupling portion between the system input shaft 18 and a coupling portion between the output shaft (motor shaft) 20 of the HST 8 and the traveling system input shaft 21 of the gear transmission case 3 are equipped with vibration-absorbing ball shaft joints 22, respectively. .
Further, a speed change operation shaft 23 of the HST 8 is protruded from a through hole of the housing 4 provided with the rubber seal member 24 to the outside, and an operation arm 25 is attached to an outer end of the operation shaft 23 through a vibration absorbing rubber 26. It is fitted and connected to the speed change pedal 27 and is linked to the ring. The housing 4 has a pair of detection ports 28 and 29 for measuring the hydraulic pressure of the forward high-pressure side circuit and the hydraulic pressure of the reverse high-pressure side circuit of the HST 8, a charge oil supply port 30, and a charge oil discharge port 31. These ports are respectively provided and the corresponding boats of the HST 8 are connected by rubber pipes 32, respectively.

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 attached drawings.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a mounting portion of a hydrostatic type continuously variable transmission.

FIG. 2 is a front view of a hydrostatic stepless transmission mounting portion.

FIG. 3 is an exploded perspective view of a mounting portion of the hydrostatic stepless transmission.

FIG. 4 is a longitudinal sectional side view of an anti-vibration connection portion.

FIG. 5 is an overall side view of the agricultural tractor.

[Explanation of symbols]

 Reference Signs List 1 engine 3 gear transmission case 8 hydrostatic continuously variable transmission (HST) 9 transmission shaft 11 case 17 input shaft 20 output shaft 21 input shaft 22 shaft coupling

Claims (1)

(57) [Claims] An intermediate mounting member (12) is mounted on a gear transmission case (3) via a vibration isolating member (15), and the intermediate mounting member (12) is mounted on a hydrostatic stepless transmission (8). The case (11) is rigidly connected, and the output shaft (20) of the hydrostatic continuously variable transmission (8) and the input shaft (21) of the gear transmission case (3) are connected to a vibration-absorbing type shaft coupling (22). Work vehicle connected by.