JPH0696392B2 - Work vehicle steering mechanism - Google Patents

Description

TECHNICAL FIELD The present invention relates to a steering mechanism such as a knuckle arm or a kingpin when a steering wheel is also driven in a traveling work vehicle for agriculture or construction. It is a thing.

(B) Prior art A conventional steering mechanism in a steered wheel drive type traveling vehicle has a kingpin rotation mechanism as disclosed in, for example, Japanese Utility Model Publication No. 56-15107 and Japanese Utility Model Publication No. 60-9105. The center of motion and the center of rotation of the knuckle arm coincided with each other.

However, in the case of the conventional steering mechanism in a steering wheel drive type traveling vehicle, the turning angle of the knuckle arm must be large and the turning angle of the steering handle must be large. When the operation angle of is small, there is a problem that the turning angle of the steering wheel becomes too small.

(C) Problems to be Solved by the Invention An object of the present invention is to make the turning angle of the knuckle arm small so that even if the turning angle of the knuckle arm is small, the steering turning of the steering wheel is large. It is configured to be possible.

With such a configuration, particularly in a radio-controlled traveling vehicle or the like, the steering wheel can be largely rotated even if the operating width of the actuator of the steering drive mechanism is small.

(D) Means for Solving the Problems The object of the present invention is as described above, and a configuration for achieving the object will be described below.

The steering wheel drive unit is composed of a fixed gearbox 22 and a steering gearbox 20, the fixed gearbox 22 is fixed to the machine body, and a kingpin is provided in the fixed gearbox 22.
35 is rotatably supported, and a steering gearbox 20 for supporting steering wheels is rotatably supported on the outer periphery of a portion where the kingpin 35 projects from the fixed gearbox 22. The knuckle arm shaft 28 forming the rotation center O1 of the knuckle arm 21 is disposed at a position where the axis of the kingpin 35 in the box 22 is displaced, and the knuckle arm 21 is connected to the lower end of the knuckle arm shaft 28 for steering. The knuckle arm 21 is rotated by an operating mechanism, and the other end of the knuckle arm 21 is engaged with the rotating arm 32 protruding from the steering gear box 20, and the king pin 35
The steering gear box 20 is configured so as to be steered and rotated around the.

(E) Embodiment The object and structure of the present invention are as described above, and the structure of the embodiment shown in the accompanying drawings will be described below.

FIG. 1 is a side sectional view of a radio-controlled lawnmower work vehicle of the present invention,
2 is a side view of the support portion of the front wheel 1 which is a steering wheel, FIG. 3 is a front sectional view of the drive portion of the front wheel 1, FIG. 4 is a side sectional view of the same, and FIG. 5 is a knuckle arm 21 of the same. FIG. 3 is a plan view illustrating a rotation angle of a steering gear box 20.

The overall structure will be described with reference to FIGS. 1 and 2.

The mower device is composed of a mower deck 3 and a rotary cutting blade 4. A deck frame 5 is arranged on the upper surface of the mower deck 3. An engine E is placed on the rear portion of the deck frame 5, a mission case M is placed on the central portion, and a battery 13 is placed on the front portion.

Power is transmitted from the engine E into the mission case M,
A shaft for driving the rotary cutting blade 4 from the mission case M is projected as a working machine drive shaft 23 from the mission case M into the mower deck 3. Further, a universal joint shaft 9 for driving the front wheels 1 which are steering wheels is interposed, and by this, power is transmitted to the fixed gear box 22. The steering gearbox 20 is arranged below the stationary gearbox 22.

Parallel links 11 and 12 for vertically moving the fixed gearbox 22 for adjusting the cutting height are interposed between the transmission case M and the fixed gearbox 22.

Further, the steering drive mechanism 14 for steering and rotating the front wheel 1 which is the steering wheel is also pivotally supported at its base portion on the mission case M by a joint. The steering drive mechanism 14 is composed of a forward / reverse motor and a screw rod, etc., and the telescopic cylinder 30 extends and contracts, and the tip of the telescopic cylinder 30 has a knuckle arm 21 formed in a bell crank shape by a pivot pin 29. It is pivotally connected to the end arm 21a.

The knuckle arm 21 has a knuckle arm shaft 28, and a rear portion of the knuckle arm 21 is a pivotal support portion 22b formed as a part of a fixed gearbox 22.
The front end of the pivot arm 32 projects from the steering gear box 20 and engages the pivot arm pin 33 of the pivot arm 32 in the long hole 21b.

Since the center of the knuckle arm shaft 28 and the center of the kingpin, which is the center of rotation of the steering gearbox 20, are not aligned,
The steering gearbox 20 is steered and rotated while absorbing the eccentric portion by the long hole 21b provided at the tip of the knuckle arm 21 and the rotating arm pin 33.

Further, a cutting height adjusting rod 16 and a cutting height adjusting pipe 15 are provided between the mower deck 3 and the parallel links 11 and 12, and the cutting height of the front wheels is changed by changing the distance between the two. It is configured to adjust the height.

The rear wheels 2 are provided on the left and right, and the rear axle cases 18 and 19 of the rear wheels 2 have their front ends pivotally supported on the mission case M and their rear ends drilled on the cutting height adjustment bracket 17. It is configured so that it can be adjusted and fixed by a pin in the adjustment hole of the stage.

The cutting height of the mower device is adjusted by adjusting the front wheel 1 with the cutting height adjusting pipe 15 and the cutting height adjusting rod 16 and adjusting the upper and lower positions of the rear axle cases 18 and 19 with respect to the cutting height adjusting bracket 17. It is what you are doing.

Bumper guards 6 and 7 are provided in front of and behind the deck frame 5.

The bonnet 8 covers the entire configuration as described above. A warning light 10 for radio control is attached to the top of the bonnet 8.

In FIGS. 3, 4, and 5, the front wheel 1 which is a steering wheel
The steering mechanism will be described.

As shown in FIG. 4, the stationary gear box 22 has a "universal joint shaft 9 connected to the rear end of the front wheel input shaft 34 that is bent in a mold and projects rearward.

The bevel gear 34a at the front end of the front wheel input shaft 34 meshes with the upper bevel gear 35a of the kingpin 35.
The king pin 35 constitutes the central axis of rotation of the front wheel 1 and also serves as a power transmission shaft. That is, the lower bevel gear 35b of the king pin 35 meshes with the bevel gear 36a of the sprocket shaft 36, and the other end is inserted into the steering chain case 20a.

A chain is wound around the sprocket 37a of the front axle 37 from the sprocket 36b at the other end of the sprocket shaft 36,
The front wheel 1 is supported by the front axle 37.

In this configuration, the sprocket shaft 36, the steering chain case 20a, and the front axle 37 are configured in an "inverted U shape",
The center of the steering rotation of the front wheel 1 is located just below the center of the kingpin 35.

As described above, the knuckle arm shaft 28, which is the center of rotation of the knuckle arm 21, is provided at the rear of the fixed gear box 22 at a position deviated from the center line of the front wheel input shaft 34, and the steering of the front wheel 1 is performed. Since the kingpin 35, which is the center of rotation, is located forward, the rotation center O1 of the knuckle arm 21 and the rotation center O2 of the kingpin 35 do not match.

In the prior art, the center of rotation of the knuckle arm 21
It was common sense that O1 and the center of rotation O2 of the kingpin 35 coincided.

When they match, the turning angle of the knuckle arm 21 becomes the steering turning angle of the front wheel 1 as it is, and therefore the knuckle arm 21 needs to be turned largely by about 180 degrees.

In particular, in the case of the radio-controlled lawnmower work vehicle of the present invention, it is necessary to rotate about 180 degrees in order to enable a small turn, and in this case, the steering drive mechanism 14 expands and contracts. The cylinder 30 needs to expand and contract greatly, which makes the configuration difficult.

In order to solve the problem, the present invention intentionally disagrees with the rotation center O1 of the knuckle arm 21 and the rotation center O2 of the kingpin 35, thereby reducing the rotation angle of the knuckle arm 21. The rotation angle of the king pin 35 is large.

For this reason, a displacement of the rotation angle occurs between the knuckle arm 21 and the steering gear box 20, and the knuckle arm 21 is provided with a long hole 21b in order to absorb this displacement. .

In the elongated hole 21b, a rotating arm pin 33 of a rotating arm 32 protruding from the steering gear box 20 side is fitted.
The displacement is absorbed by the rotation arm pin 33 sliding in the elongated hole 21b.

In FIG. 5, the steering gear box 20 is configured to rotate by an angle θ2 with respect to the rotation angle θ1 of the knuckle arm 21, and the relationship between θ1 and θ2 is such that θ2> θ1. I am doing it.

Further, in FIG. 5, the rotation center O1 which is the center of the knuckle arm shaft 28 and the telescopic cylinder 30 of the knuckle arm 21.
The arm 21a is positioned forward by an angle θ3 with respect to the line connecting the center of the pin hole at the tip of the arm 21a, which is the pivotal connection part with the side, and by this configuration, the arm 21a is located more than the connecting part with the telescopic cylinder 30. , When the arm 21a is pushed, arm 2
There is no longer a dead point that is a branch point between 1a going forward and going backward.

(H) Effects of the Invention Since the present invention is configured as described above, it has the following effects.

First, the center of rotation O1 of the knuckle arm 21 and the kingpin
Knuckle arm 21 by shifting the center O2 of 35
Even if the turning angle of the steering wheel is small, the steering turning angle of the front wheel 1 which is the steering wheel can be made large, and when the steering drive mechanism 14 is configured by the telescopic cylinder, the telescopic amount of the telescopic cylinder 30 is extended. Even if it is small, it will be better.

Further, when the steering wheel is operated, the turning angle of the steering wheel can be reduced and the steering turning angle of the steering wheel can be increased.

As described above, it is possible to reduce the turning radius of the machine body by increasing the turning angle of the front wheel 1 which is a steered wheel.

Secondly, a mechanism for connecting the knuckle arm 21 to the steering drive mechanism is provided by the knuckle arm shaft 28 on the fixed side gearbox 22.
Since it can be connected to the portion protruding downward through, it can be arranged at a position lower than the fixed gearbox 22, and the steering drive mechanism such as the telescopic cylinder can be arranged at a lower position, Since it does not interfere with other members, the stroke of the steering drive mechanism can be increased.

[Brief description of drawings]

FIG. 1 is a side sectional view of a radio-controlled lawnmower work vehicle of the present invention,
2 is a side view of the support portion of the front wheel 1 which is a steering wheel, FIG. 3 is a front sectional view of the drive portion of the front wheel 1, FIG. 4 is a side sectional view of the same, and FIG. 5 is a knuckle arm 21 of the same. FIG. 3 is a plan view illustrating a rotation angle of a steering gear box 20. 1 …… Front wheel which is a steering wheel 14 …… Steering drive mechanism 20 …… Steering gearbox 20a …… Steering chain case 21 …… Knuckle arm 22 …… Fixed side gearbox 28 …… Knuckle arm shaft 32… … Rotating arm 33 …… Rotating arm pin 35 …… King pin 37 …… Front axle O1 …… Knuckle arm pivot center O2 …… King pin pivot center E …… Engine M …… Mission case

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takumi Tanaka 1-32, Chaya-cho, Kita-ku, Osaka, Osaka Prefecture Yanmar Diesel Co., Ltd. (72) Noriyuki Yamakawa 1-32-32, Chaya-cho, Kita-ku, Osaka-shi, Osaka In Yanmar Diesel Co., Ltd. (56) References Jitsuko Sho 56-15107 (JP, Y2)

Claims (1)

[Claims] Claim: What is claimed is: 1. A steering wheel drive unit is provided on a stationary gear box 22.
And the steering gearbox 20, the fixed gearbox 22 is fixed to the machine body, and the kingpin 35 is rotatably supported in the fixed gearbox 22. On the outer periphery of the portion protruding from the box 22, a steering gear box 20 that supports the steering wheels is rotatably supported.
The knuckle arm shaft 28 forming the rotation center O1 of the knuckle arm 21 is penetratingly arranged at a position where the axis of the king pin 35 in the fixed gear box 22 is displaced, and the knuckle arm 21 is provided at the lower end of the knuckle arm shaft 28. It is rotated by the connected steering operation mechanism, and the other end of the knuckle arm 21 is engaged with the rotating arm 32 protruding from the steering gear box 20,
A steering mechanism for a work vehicle characterized in that the steering gearbox 20 is configured to rotate around the kingpin 35.