JP3311854B2 - Tractor steering mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a small tractor to mount the Ronmoa such as the abdomen, the present invention relates to a structure of the steering Organization.

[0002]

2. Description of the Related Art Conventionally, a ball screw type steering mechanism has been used in a manual steering mechanism of a tractor. In the case of the ball screw type, a backlash of a gear is required to adjust a play of a steering wheel. There was a problem that adjustment was required. Further, in order to operate the drag rod, it was necessary to interpose a pitman arm between the column shaft and the drag rod. When the pitman arm is disposed below the column shaft in this manner, the pitman arm protrudes from the abdomen of the tractor, so that there is a problem in that the pitman arm interferes when the lawn mower is raised .

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a small tractor equipped with a lawn mower on its abdomen, which can be equipped with a midman utmore.
When the mid-mount mower is raised, the driven spur gear and the driving helical gear are configured horizontally so that the lawn mower does not interfere with the pitman arm constituting the steering device. In addition, by configuring the driven side spur gear and the drive side helical gear,
Since an excessive load is applied to the drag rod, a cylindrical spring as an elastic body is interposed.

[0004]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. In claim 1, a loan to the abdomen
The tractor's steering mechanism with mowers etc.
The steering hand at the center of the left and right sides of the tractor.
The dollar D and the column shaft 1 are arranged, and the steering wheel
The column shaft 1 rotated by the handle D extends downward.
Drive-side helical gear at the lower end of the column shaft 1
And a driven side gear meshing with the drive side helical gear 3.
The pargear 2 is positioned eccentric from the center of the tractor.
Driven by a vertical support shaft 45, and the driven spur gear
The two tooth traces are arranged vertically, and the spur teeth of the vertical tooth traces
Torsion angle of tooth trace of drive side helical gear 3 to mesh with car
a is the same as the rearward inclination angle of the column shaft 1 .

[0005] According to claim 2, the tiger according to claim 1 is provided.
Driven spur gear 2
Manual stay that pivots the rear end of the drag rod 4
The drag rod 4 is divided into front and rear by using the ringing mechanism.
And the elastic body 38 is interposed between the drag rods 4
The elastic body 38 is configured to absorb the difference in the amount of pulling movement.
It is a thing.

[0006]

Next, the operation will be described. In the first aspect, since the driven-side spur gear 2 and the driving-side helical gear 3 are configured to mesh with each other, the backlash between the two can be optimized by slightly changing the inclination of the column shaft 1. is there. This makes it easy to manage the backlash, that is, to adjust the play clearance of the steering handle D. Also, parts such as a pitman arm can be eliminated as compared with the conventional case. Also, unlike the conventional pitman arm, without protruding downward,
Since the driven-side spur gear 2 is formed in a planar shape, a large vertical stroke of the lawn mower M can be taken. Further, by changing the fraction of the driven spur gear 2 with respect to the driving helical gear 3, the rotation speed and the operating force of the steering handle D can be easily changed.

According to the second aspect, the excessive push-pull force generated for pushing and pulling the drag rod 4 by the rotation of the driven spur gear 2 can be absorbed by the elastic body 38. , A uniform operating force of the drag rod 4 can be obtained. Further, since the elastic body 38 is interposed in the portion of the drag rod 4, it is possible to prevent the other parts from being damaged due to an excessive operation force, so that the strength of the other parts is reduced and the weight is reduced. You can.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a side view of the tractor of the present invention having a catcher box B at the rear and a lawn mower M on the abdomen. FIG. 2 is a side view of a left column cover 40, a central column cover 41, and a bonnet 42 of the present invention. 3 is a plan view of a hood 42, a left column cover 40, and a center column cover 41, FIG. 4 is a side view of a steering handle D and a steering mechanism, and FIG. 5 is a driven spur gear 2 and a driving helical. FIG. 6 is a plan view of the column shaft 1 of the gear 3 part.
Rear view of the steering handle D and the steering mechanism,
7 is a plan view of the steering mechanism of the present configuration when the vehicle is traveling straight, FIG. 8 is a plan view of the steering mechanism of the present configuration when the vehicle is turning, and FIG. 9 is a side view of the drag rod 4 with an elastic body 38 interposed therebetween. FIG. 10 is a plan sectional view of a column cover part, and FIG.
1 is a drawing showing the relationship between the torsion angle a of the driving side helical gear 3 and the driven side spur gear 2.

FIG. 1 shows a tractor in which a lawn mower M and a catcher box B are mounted. The tractor uses the frame F as a support base.
A hood 42 is disposed on the upper front end of the frame F, and the right and left rear portions of the hood 42 are covered with a right column cover 39 and a left column cover 40.
And a rear portion of the left column cover 40 is covered with a central column cover 41 which is detachable in the front-rear direction. The engine E is installed inside the hood 42 and the column cover.
As shown in FIG. 2, the cooling air is sucked from the rear and discharged to the front by providing a suction fan 44 at the rear, with the rear being lowered obliquely as shown in FIG.

Below the frame F, the front wheels 30
A lone mower M is suspended and supported between the rear wheel 31 and the rear wheel 31. The front of the Lone More M is a front suspension link 18
With this, the rear part is suspended and supported by the rear suspension link 19,
It can be raised and lowered by a lifting cylinder (not shown). A thrower S is disposed on the right side of the lawn mower M, and the lawn mower cut by the lawn mower M is thrown to the chute spout 15 via the connecting hose 6 by the thrower S. The chute spout 15 is open inside the catcher box B, so that the cut grass is filled in the catcher box B. The catcher box B includes a front fixed part 11 and a rear lid part 12. The lid part 12 is opened by turning upwardly of a box opening / closing lever 10 arranged on the right side of the operator to cut grass. Can fall.

The power from the front of the engine E is transmitted to the joint shaft 17 and the input box 2
0, which drives both the lawn mower M and the slower S. Further, a shaft at the rear of the engine E is transmitted to the HST transmission H via a joint shaft.
The rotation after the speed change by the ST-type transmission H is input to the transmission case C to drive the rear wheels 31 that are driving wheels.

In the overall configuration as described above, the present invention relates to a mechanism for operating a drag rod 4 by a steering handle D as shown in FIGS. That is, the column shaft 1 is rotated by the steering handle D. The column shaft 1 extends to a lower portion inside the center column cover 41, and a driving helical gear 3 is engraved at a lower end of the column shaft 1.

A steering handle D and a column shaft 1 are arranged at the left and right center positions of the tractor, that is, at the center position of the frame F. And the column shaft 1
The driven spur gear 2 meshing with the drive side helical gear 3 arranged below is pivotally supported by a vertical support shaft 45 at a position eccentric from the center line. The tooth trace of the driven spur gear 2 is arranged in the vertical direction, and only the torsion angle a is set so that the tooth trace of the driving helical gear 3 is also vertical so as to mesh with the spur gear of the vertical tooth trace. Tilt column shaft 1
Is arranged. Thereby, the teeth of the driving side helical gear 3 and the driven side spur gear 2 can mesh with each other on a vertical line as shown in FIG.

Thus, there is no pitman arm,
Since the drag rod 4 is directly connected to the driven spur gear 2, as shown in FIG. 4, the drag rod 4 is disposed obliquely with the rear portion being high, and even if the lawn mower M is raised from below, the drag rod 4 is moved. There is no interference with. Of course, since there is no pitman arm, there is no interference with the lawn mower M. However, as shown in FIGS. 7 and 8, since the drag rod 4 is pushed by the rotating driven spur gear 2, the moving width of the drag rod 4 is not linear as compared with the case of the pitman arm. Thereby, the drag rod 4
Is changed depending on the rotational position of the driven spur gear 2. In order to solve this inconvenience, in the present invention, the drag rod 4 is divided into front and rear portions 4a and 4b, and an elastic body 38 is interposed therebetween. And the operating force is the same.

In FIG. 10, the right column cover 39
And the assembled state of the left column cover 40 and the center column cover 41. The right column cover 39 and the left column cover 40 can be removed, but the center column cover 41 can be attached and detached forward and backward.
Then, when the central column cover 41 in the shape of “C” is mounted facing forward, the front end of the central column cover 41 and
Since there is a possibility that a gap is formed between the right column cover 39 and the left column cover 40, guide pieces 41a and 41b are formed at the front of the center column cover 41. The guide pieces 41a and 41b are attached to the right column cover 3
9 engages with the rear end of the left column cover 40 and pushes the center column cover 41 forward, the guide pieces 41a and 4a
1b enters the inside of the right column cover 39 and the left column cover 40, thereby eliminating the gap created by the spread of the front end of the center column cover 41.

[0016]

As described above, the present invention has the following advantages. With the configuration as described in claim 1, by slightly changing the inclination of the column shaft 1 at the meshing portion between the driven-side spur gear 2 and the driving-side helical gear 3, the backlash between the two can be optimized. You can. This makes it easy to adjust the backlash, that is, to manage the play clearance of the steering handle D. Also, parts such as a pitman arm can be eliminated as compared with the conventional case. Further, since the driven spur gear 2 does not protrude downward like a pitman arm and is formed in a flat shape, the lawn mower M
Can take a large lifting stroke.
Further, by changing the fraction of the driven spur gear 2 with respect to the driving helical gear 3, the rotation speed and the operating force of the steering handle D can be easily changed.

According to the second aspect of the present invention, the excessive pushing / pulling force generated for pushing / pulling the drag rod 4 by the rotation of the driven spur gear 2 can be absorbed by the elastic body 38. A uniform operation force of the drag rod 4 can be obtained over the entire operation range of the handle D. Further, since the elastic body 38 is interposed in the portion of the drag rod 4, it is possible to prevent the other parts from being damaged due to an excessive operation force, so that the strength of the other parts is reduced and the weight is reduced. You can.

[Brief description of the drawings]

FIG. 1 is a side view of a tractor of the present invention in which a catcher box B is provided rearward and a lawn mower M is provided on an abdomen.

FIG. 2 is a side view of a left column cover 40, a center column cover 41, and a hood 42 of the present invention.

FIG. 3 also shows a hood 42 and a left column cover 40
FIG. 4 is a plan view of a portion of a central column cover 41.

FIG. 4 is a side view of a steering handle D and a steering mechanism.

FIG. 5 is a plan view of the driven spur gear 2 and the driving helical gear 3;

FIG. 6 is a rear view of a column shaft 1, a steering handle D, and a steering mechanism.

FIG. 7 is a plan view of the steering mechanism of the present configuration when traveling straight.

FIG. 8 is a plan view of the steering mechanism having the same configuration when turning.

FIG. 9 is a side sectional view showing a state in which an elastic body 38 is interposed in the drag rod 4;

FIG. 10 is a plan sectional view of a column cover part.

FIG. 11 is a view showing a relationship between a torsion angle a of a driving side helical gear 3 and a driven side spur gear 2;

[Explanation of symbols]

 D Steering handle 1 Column shaft 2 Driven spur gear 3 Drive side helical gear 4 Drag rod 38 Elastic body 39 Right column cover 40 Left column cover 41 Central column cover

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 3/00-3/02 B62D 49/00 B62D 1/16-1/20

Claims (2)

(57) [Claims] 1. A tractor for mounting a lawn mower on the abdomen
-The steering mechanism of the
In the center position, steering handle D and column shaft 1
And the steering wheel D rotates the
The ram shaft 1 is extended downward, and the column shaft 1
The drive side helical gear 3 is provided at the lower end of the
Driven spur gear 2 meshing with the
By the vertical support shaft 45 at a position eccentric from the center position of the
The spur gear of the driven-side spur gear 2 pivots and is arranged vertically.
To the drive side so as to mesh with the spur gear of the vertical tooth trace.
The torsion angle a of the tooth trace of the ryical gear 3 is
Tractor characterized by having the same backward inclination angle
-Steering mechanism . 2. A tractor steering system according to claim 1,
In the mechanism, a drag rod 4 is attached to the driven spur gear 2.
A manual steering mechanism with the rear end pivoted,
The drag rod 4 is divided back and forth, and an elastic body 38 is interposed therebetween.
The difference in the amount of push / pull movement of the drag rod 4
Characterized in that it is configured to be absorbed by the
Lactor steering mechanism .