JPH02256568A - Steering device for working vehicle - Google Patents

Abstract

PURPOSE:To permit the rough position adjustment of a stopper for regulating the max. steering angle by providing an elastic deflection onto one drag link, in the constitution in which each drag link of the front and rear wheel steering mechanisms is connected to a pitman arm interlocked with a steering wheel. CONSTITUTION:The steering device for a four-wheel steered working vehicle such as lawn mower is constituted by connecting the drag link 22 of a steering mechanism A for front wheels 1 and the drag link 25 of a steering mechanism B for rear wheels 2 with a pitman arm 12 which is turned by a steering wheel 9. The front and rear wheels 1 and 2 are steered in the reverse direction each other by the operation of the steering wheel 9, and the max. steering angle of the front and rear wheels l and 2 is regulated by stoppers 26 and 27. In this case, the drag link 25 for the rear wheels 2 is formed into bent form, and after the knuckle arm 24 of the rear wheel 2 contacts a stopper 27 by the elastic deflection due to the deflection of the link 25, the stopper 26 on the knuckle arm 20 of the front wheel 1 collides with an axle frame.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention connects a drag link of a front wheel steering mechanism and a drag link of a rear wheel steering mechanism to a pitman arm linked to a steering wheel. This invention relates to a steering device for a working vehicle, which is constructed such that the front wheels and rear wheels can be operated in opposite directions by operating the handle, and is provided with a stopper that limits the maximum steering angle of each of the front wheels and rear wheels. .

[Conventional technology]

Such a work vehicle is equipped with a stopper that restricts the maximum operating angle of each of the front wheels and the rear wheels, so when the steering wheel is operated to the maximum, mechanical play in the steering mechanism is absorbed and turning is smooth. This has the advantage of preventing the front and rear wheels from wobbling when the wheels move.

In conventional work vehicles, a stopper that contacts the knuckle arm of the steering mechanism to limit the maximum operating angle of each of the front wheels and rear wheels is placed in contact with the front wheels and rear wheels at the same time. It was set up to do so.

[Problem to be solved by the invention]

In this way, when the stopper that restricts the maximum operating angle of the front wheels and the rear wheels is brought into contact with the front wheels and the rear wheels at the same time, the play of the steering mechanism that inevitably occurs, that is, the steering Since looseness inevitably occurs due to errors in manufacturing and assembly of the mechanism, it is virtually impossible to keep both stoppers in contact with the front and rear wheels at the same time. There is an inconvenience that the other side does not touch in advance.

Therefore, as a means to eliminate the above-mentioned drawbacks, the stopper is constructed from an adjustment bolt so that the position of the stopper can be adjusted. However, since the stopper is destroyed by repeated action, each stopper is In order to operate properly, the stopper position had to be adjusted frequently.

SUMMARY OF THE INVENTION An object of the present invention is to provide a steering device in which each stopper can always reliably regulate the maximum operating angle of a front wheel and a rear wheel without frequently adjusting the position of the stopper.

[Means to solve the problem]

The characteristic configuration of the present invention taken to achieve the above object includes elastic flexibility that allows elastic deformation in the direction of steering operation in one of the two drag links, and
A stopper for regulating the maximum steering angle of the wheel on the drag link side equipped with this elastic flexibility comes into contact first, and when this stopper is in contact, the elastic flexibility of one drag link is elastically displaced, causing the other drag link to move. The pitman arm and both steering mechanisms are linked together so that the stopper for regulating the maximum steering angle of the side wheels acts in rear contact, and its functions and effects are as follows.

[For production]

When you turn the steering wheel all the way, either the front wheel or the rear wheel hits the stopper for that wheel first, and the rattling of the steering mechanism on the side that hit first is absorbed, preventing that wheel from rattling. At the same time, in this state, when the steering wheel is rotated more strongly, the elastic flexibility of the drag link 4 in the steering mechanism on that side is elastically deformed, the handle is rotated slightly, and the rotation operation causes the other wheel to rotate. When the stopper for the wheel hits the rear, the backlash of the steering mechanism on the side that hit the rear is absorbed, the wheel is prevented from rattling, and the front and rear wheels are prevented from rattling.

〔Effect of the invention〕

As a result of the above configuration, even if some damage occurs, the maximum operating angle of both wheels can be regulated by the stopper without the need to adjust the position of the stopper, and the front and rear wheels will not wobble when the aircraft turns. This has led to improved riding comfort.

〔Example〕

Figure 5 shows a riding lawn mower as an example of an agricultural vehicle.
This lawnmower has a pair of left and right front wheels (1).

(1) and a pair of left and right rear wheels (2), an engine (4) is mounted on the front part of the body frame (3), and a hydrostatic stepless hydraulic engine is mounted on the rear part of the body frame (3). A transmission (5) and a transmission case (6) are provided, and the power from the engine (4) is transmitted to the hydrostatic continuously variable transmission (5).
It is transmitted to the rear transmission case (6) via the. and configured to transmit power from the rear transmission case (6) to the rear wheels (2), (2), and
A vehicle body frame (3) is provided with a driving portion (10) including a steering handle (9) for steering the front wheels (1), (1) and the rear wheels (2), (2),
A lawn mower (11) is drivably arranged between the front and rear wheels (1) and (2).

In the lawn mower, the radiator (12) is moved from around the driving part (10), where there is relatively little floating matter such as straw and dirt.
The cooling air around the driving part (10) is designed to suck in the cooling air around the driving part (10) so that it is difficult for much straw, dirt, etc. to adhere to the dustproof net (13) for the radiator (12). to the body cover (15) under the seat (14) in order to attract the parts to the hydrostatic continuously variable transmission (5) side.
A suction port (17) is formed for the cooling fan (16) of the hydrostatic continuously variable transmission (5).
) is provided with a dustproof screen (18).

To explain the steering devices for the front wheels (1) and rear wheels (2), as shown in FIG.
The knuckle arm (1) is connected to the tie rod (19) so that it can rotate integrally, and is attached to the left front wheel (1).
20) and a pitman arm (21) linked to the steering handle (9) are interlocked via a drag link (22), and the front wheels (1) can be steered by rotating the steering handle (9). It is configured as follows.

Similarly, the left and right rear wheels (2), (2) are connected to the tie rod (
23), and the knuckle arm (24) attached to the right rear wheel (2) and the pitman arm (21) are interlocked and connected via a drag link (25). , is configured so that it can be steered to the side opposite to the front wheels (1) by rotating the steering handle (9).

In the lawn mower, when the handle (9) is turned fully left or right, the front wheel (1) steering mechanism (
A) and a stopper that absorbs the play of the steering mechanism (B) of the rear wheel (2) and prevents the front wheel (1) and the rear wheel (2) from wobbling, that is, the steering mechanism (A ), (B) knuckle arm (20), (
a stopper (26) that limits the maximum operating angle of the front wheel (1) and the rear wheel (2) by contacting and preventing the rocking of the front wheel (24);
), (27) are provided. And the rear wheels (2
) is arranged so that the stopper (27) for the front wheel (1) comes before the stopper (26) for the front wheel (1). Specifically, the front wheel stopper (26) is configured as a pin implanted in the left and right knuckle arms (20), and is in contact with the axle frame, which is a part of the vehicle body, so that the knuckle arms (20) Prevents the rocking. Further, the rear wheel stopper (27) is configured as an adjustment bolt provided on the left and right axle case portions.

Then, the drag link (25) of the rear wheel (2) is bent and formed to increase the length of the link, and the knuckle arm (
24) comes into contact with the stopper (27), then the front wheel (1
) on the knuckle arm (20) of the stopper (26).
) is configured so that it can be rear-attached to the axle frame.

The lawn mower has a steering mechanism that moves from a rear wheel (2) equipped with a knuckle arm (24) as shown in FIG. 3 to a rear wheel (28) without a knuckle arm as shown in FIG. By replacing the front and rear wheels (1),
(2) It is configured to be able to switch from a state in which steering operation is possible to a state in which only the front wheels (1) can be steered.

[Another example]

In providing elastic flexibility to the drag link, a short drag link (22) for the front wheel (1) may be provided instead of a long drag link (25) for the rear wheel (2).

Further, as a means for providing elastic flexibility to the drag link, an elastic member such as a coil spring may be interposed in the middle of the link.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of drawings]

The drawings show an embodiment of the steering device for a working vehicle according to the present invention,
Figure 1 is a plan view showing the main parts, Figure 2 is a schematic diagram showing the operating state of the steering mechanism, Figure 3 is a partially cutaway rear view showing the rear wheel, and Figure 4 is a different rear wheel installed. FIG. 5 is a longitudinal cross-sectional rear view of the main parts, and a side view showing the entire riding lawn mower. (1)...Front wheel, (2)...Rear wheel, (9)...Handle, (21)...
Pitman arm, (22). (25)...Drag link, (26),
(27)・・・Stopper (A)・・・・・・
Front wheel steering mechanism, (B)... Rear wheel steering mechanism.

Claims (1)

[Claims] On the pitman arm (21) linked to the handle (9),
Drag link (22) of the front wheel (1) steering mechanism (A) and rear wheel (2) steering mechanism (B)
The front wheel (1) and the rear wheel (2) are connected to the drag link (25) so that the front wheel (1) and the rear wheel (2) can be operated in opposite directions by operating the handle (9). (2) A steering device for a working vehicle, which is provided with stoppers (26) and (27) for abutting and regulating the maximum steering angles of the respective drag links (22) and (25).
One of the wheels is provided with an elastic flexibility that allows elastic deformation in the direction of steering operation, and a stopper for regulating the maximum steering angle for the wheel on the drag link side equipped with this elastic flexibility is placed in advance, and this stopper (27 ), the pitman arm (21) and the stopper for controlling the maximum steering angle act against the wheels on the other drag link side by elastically displacing the elastic flexibility of one drag link in the abutting state. Both steering mechanisms (A),
(B) A steering device for a working vehicle that is linked and set.