JPH0225742Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has the engine and transmission case located above the front part of the steering front wheels, a working device behind the rear wheels, and a driver's seat between the front and rear wheels. A steering device used in a work vehicle such as a riding rice transplanter, which aims to balance the weight between the front and rear, and also provides a steering speed reduction mechanism for the steering wheel located in front of the driver's seat to facilitate and simplify steering wheel operation. Regarding.

In the above-mentioned steering device for a work vehicle, conventionally, as disclosed in, for example, Japanese Utility Model Application Publication No. 56-142525, a deceleration chamber housing the steering deceleration mechanism is disposed at the front side of the transmission case. There was a structure in which the pitman arm drive shaft was provided on the front side of the handle shaft, and the handle shaft was arranged on the front outer side of the mission case.

The conventional structure described above aims to shorten the wheelbase and optimize the weight balance by locating the handle shaft ahead of the front wheel axle case.

However, in the conventional structure described above, since the steering reduction chamber protrudes toward the front side of the transmission case, the gap between the engine and the transmission case must be increased, resulting in an increase in the overall length of the aircraft. Ta.

An object of the present invention is to provide a steering device for a work vehicle that can optimize the front-rear weight balance of the machine body and also make the overall length of the machine body compact.

The characteristic structure of the steering device for a work vehicle according to the present invention, which has been made to achieve the above object, is that a steering gear reduction chamber is provided in the lower part of the transmission case, which is independent of the traveling transmission chamber, and a lower part of the steering gear reduction chamber is provided. In addition to linking the pitman arm attached to the front wheel with the front wheel steering link mechanism, the steering wheel shaft extends upward from the steering gear reduction chamber through the outside of the transmission case.

The effects of the present invention having such a characteristic configuration are as follows.

In other words, since the gear transmission chamber is provided at the bottom of the transmission case, there are no unnecessary parts between the transmission case and the engine, and they can be placed close together, resulting in a shorter and more compact aircraft. can. Moreover, since the gear reduction chamber is provided at the lower part of the transmission case, this gear reduction chamber can be multi-functional in that it functions as a protector for the traveling transmission chamber of the transmission case. Even if this gear reduction chamber were to collide with an obstacle and be damaged, the amount of lubricating oil that would leak outside would be much smaller than that in the traveling transmission chamber, so the impact of the leakage would be kept to a minimum. It has many advantages.

Hereinafter, embodiments of the present invention will be described based on the drawings.

As shown in FIG. 1, an engine 3 is mounted on the fuselage frame 2 extending above and in front of the steering front wheels 1 via anti-vibration rubber, and the engine 3 is mounted behind the engine 3. A planting mechanism is installed at the tip of a vertically movable quadruple link mechanism 6 which is installed behind the rear wheels 5 and extends rearward from the rear end of the fuselage. 7. Equipped with a seedling planting device A, which is one of the working devices consisting of a seedling stand 8, a planting case 9, and a ground float 10, and the front and rear wheels 1,
A driver's seat 11 and a steering handle 12 are provided between the rice transplanters 5 and 5 to constitute a riding-type rice transplanter.

As shown in FIGS. 2 to 4, to describe the power transmission structure, a rolling transmission case 15 with a differential mechanism 16 installed is connected to the output shaft 14 of the transmission case 4, which is transmitted to the engine 3 and the belt 13. A rear wheel transmission case 1 which is operably supported and transmission-connected and has a side clutch installed therein via a transmission shaft 17 extending from the transmission case 15.
8 to constitute a traveling transmission system,
PTO shaft 1 of a different system from the transmission case 4
9 is extended and interlocked with the planting transmission case 9 to constitute a planting transmission system.

A traveling transmission chamber 20 containing a gear transmission mechanism is formed in the upper part of the transmission case 4 equipped with such a transmission output system, and a recessed space with a downward opening is formed below the transmission chamber 20. This recessed space is closed from below with a lid member 21 to form a steering gear reduction chamber 22 that accommodates the reduction gear mechanism of the steering handle 12. The steering handle shaft 24 is pivoted to a boss portion 23 formed at the front protruding end of the transmission chamber 20, and the steering shaft 24 is rotated downward through a speed reduction mechanism consisting of 25 pairs of bevel gears and 26 pairs of spur gears. An output shaft 27 formed to protrude toward
Furthermore, a pitman arm 28 is attached to the output shaft 27, and the upper ends of wheel cases 29, 29 are interlocked and coupled to both ends of the front wheel transmission case 15 so as to be able to swing from side to side, and the pitman arm 28. and the steering link mechanism 3
0, so that the front wheels 1 can be steered.

The link mechanism 30 is connected to the wheel cases 29, 2.
9, and a connecting rod 32 that connects the knuckle arm 31 and the pitman arm 28 at their front ends so that they can swing relative to each other, and the structure of each connecting part is as follows: U-shaped portions 32A and 32A formed at both ends of the connecting rod 32 in side view are attached to mounting members 31A and 28A that are pivotally supported at the tips of the knuckle arm 31 and the pitman arm 28 so as to be rotatable around their axes. The pins 33 are connected to each other so as to be relatively rotatable. Therefore, this type of structure is advantageous in terms of cost compared to the general ball joint type.

As shown in FIG. 7, an oil filter is installed in the piping elbow 35 at the supply port 4A at the lower end of the transmission case 4, which is provided for supplying hydraulic oil to the hydraulic cylinder 34 that controls the vertical movement of the four-link mechanism 6. 36 is screwed and installed. Since the distal end portion 36a of the filter 36 is fitted into the recess 4a of the transmission case 4 in the installed state, a better supporting form can be achieved compared to a cantilever supported type, and the filter 36 is used for filtration. This effect is even more remarkable because it is a resin product in which the mesh part is integrally molded with the main body. Furthermore, since the elbow 35 is attached by screwing, the work load required for attachment and detachment during maintenance can be significantly reduced.

[Brief explanation of the drawing]

The drawings show an embodiment of the steering device for a working vehicle according to the present invention, FIG. 1 is a side view of a riding rice transplanter, FIG. 2 is a schematic plan view showing the power transmission structure, and FIG. 3 is a steering device. Partially cutaway side view,
FIG. 4 is a perspective view showing the steering link mechanism;
5 and 6 are respectively enlarged longitudinal sectional front views of the main parts of FIG. 4, and FIG. 7 is a longitudinal sectional side view showing the state in which the oil filter is attached. 1... Front wheel for steering, 3... Engine, 4...
Mission case, 5... Rear wheel, 11... Driver's seat, 20... Transmission chamber for traveling, 22... Steering gear reduction chamber, 24... Steering handle shaft, 28... Pitman arm, 30... Steering link mechanism , A... Working device.

Claims (1)

[Scope of utility model registration request] Work in which the engine 3 and transmission case 4 are installed above the front part of the steering front wheels 1, the working device A is installed behind the rear wheels 5, and the driver's seat 11 is installed between the front and rear wheels 1 and 5. This is a steering device for a car, in which a steering gear reduction chamber 22 which is independent of a driving transmission chamber 20 is provided at the lower part of the transmission case 4, and a pitman arm 28 attached to the lower part of the steering gear reduction chamber 22 and a front wheel 1 are connected to each other. A steering device for a work vehicle in which a steering wheel shaft 24 is linked to a steering link mechanism 30 and extends upward from a steering gear reduction chamber 22 through the outside of a transmission case 4.