JPS61226301A - Track-control device for vehicles - Google Patents

Abstract

PURPOSE:To aim at ease of adjustment and strength improvement, by attaching wheels to each outer end of a pair of parallel link mechanisms pivotally supported on a vertical shaft and extendedly installed in a car width direction, while constituting these link mechanisms so as to rotate around the vertical shaft, in case of a track-control device for a tractor or the like. CONSTITUTION:When a hydraulic cylinder 29 is extended or contracted and a piston rod 31 is retractably moved in or out, a support arm 20 slidingly moves in a longitudinal direction inside a long hole 32 of a rocking frame 12. And, the arm 20 swivels centering on a vertical shaft 19. With this rotation, the arm 20 and a tie rod 25 form parallel link mechanisms 28 so that front wheels 5 parallelly move while a wheel track increases or decreases. With this constitution, such a smooth motion as being high in strength takes place, thus adjustment comes easy.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a wheelbase adjustment device for a vehicle such as a tractor.

(Prior Art) Some vehicles, such as tractors, are designed to be able to adjust the wheelbase of their front wheels because they need to travel across ridges when performing management work in fields.

In this case, conventional methods have been to divide the front axle into a main body and a telescoping part that telescopically fits into the main body, pivot the main body to the vehicle body with a center shaft, and move the telescoping part in and out using a bin, etc. Normal.

There are also devices in which the telescopic section is inserted into and removed from the main body using a screw mechanism or the like.

(Problems to be solved by the invention) However, since these have a split front axle, there is a problem with strength, and the telescopic part must be inserted and removed linearly with respect to the main body, making it difficult to use. This has the disadvantage that adjustments are difficult to make.

(Hands FIt for Solving Problems) The present invention has been provided for the purpose of solving such conventional problems, and as a specific means for achieving the purpose, A pair of left and right parallel link mechanisms 28 protruding outward are pivotally supported on the vehicle body l side by a vertical shaft 19, and a wheel 5 is provided on the outer end side of each parallel link mechanism 28. A driving means 29 is provided for rotating the shaft 28 around the vertical axis 19.

(Function) When adjusting the wheelbase distance, the drive means 29 rotates the left and right parallel link mechanisms 28 around the vertical axis 19.

Then, the wheels 5 move left and right in parallel while moving back and forth due to the relative movement of the left and right parallel link mechanisms 28 with respect to the vehicle body 1, so that the wheelbase distance of the left and right wheels 5 can be adjusted.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
The figure shows a tractor, in which 1 is a tractor body, consisting of a front axle frame 2, an engine 3, a transmission case 4, etc., 5 is a front wheel, 6 is a rear wheel, and this rear wheel 6 is a rear axle case 7.
It is provided on both sides of the mission case 4 via. 8
is a bonnet, 9 is a steering wheel, 10 is a seat, and 11 is a rear wheel fender.

Reference numeral 12 denotes a swinging frame which, as shown in FIGS. 1 and 2, is disposed within the front axle frame 2, and is connected to the front axle frame 2 via center shafts 13.14 and brackets 15.16 at both front and rear ends. It is supported so that it can swing freely. A front wheel differential device 17 for transmitting power to the front wheels 5 is mounted inside the swing frame 12, and a pair of left and right support arms 20 are pivotally connected to a bracket 18 at the front end of the differential device 17 via a vertical shaft 19. There is. A transmission case 21 is fixed to the outer end of each support arm 20, and a front wheel case 22 that supports the front wheel 5 is pivoted to the transmission case 21 via a king pin 23 so as to be freely steerable.

Further, the front wheel case 22 is provided with a knuckle arm 24 that protrudes forward, and the outer end of a tie rod 25 arranged substantially parallel to the support arm 20 is connected to this knuckle arm 24. The inner end of the tie rod 25 is connected to the vertical axis 1
The steering arms 26 are connected to the steering arms 26 in front of the steering arms 9. The steering arm 26 is attached to the support plate 27 of the front axle frame 2 with the vertical axis 1
9, and is connected to a hydraulic cylinder for steering, etc. Note that the support arm 20. A parallel link mechanism 28 is constructed by the tie rods 25 and the like.

Reference numeral 29 denotes a double-acting hydraulic cylinder as a driving means, which is fixed to the swing frame 12 via a bracket 30, and a piston rod 31 of this hydraulic cylinder 29 is connected to each support arm 20 via a link 32. ing. Note that each support arm 20 is slidably inserted into a long hole 33 formed in the swing frame 12, and serves as a guide rail. Front wheel differential device 17 and transmission case 2
1 is interlocked and connected via a transmission shaft 36 having a joint 34 such as a Zeppa joint or a tripod joint, and a telescoping section 35. 5.

37 is a transmission shaft that transmits power to the front wheel differential device 17; 38
is a bumper.

In the above configuration, when the hydraulic cylinder 29 is expanded and contracted, the wheelbase distance of the front wheel 5 can be adjusted. That is, in order to increase the wheelbase distance from the state shown by the solid line shown in FIG. 1, it is sufficient to cause the hydraulic cylinder 29 to perform a contraction operation.

As a result, each support arm 20 is pulled forward and rotated about the vertical axis 19tl, thereby increasing the distance between the left and right front wheels 5. In other words, the wheelbase becomes larger. In this case, as the support arm 20 rotates, the tie rod 25 also rotates forward, so the front wheels 5 move in parallel. Since the support arm 20 is supported and guided by the swing frame 12, even if it is pivoted by the vertical shaft 19, the hydraulic cylinder 2
9 can be easily powered.

Furthermore, as the wheelbase increases, the wheelbase of the front and rear wheels 5.6 also increases, and the load shared between the front and rear wheels 5.6 can also be varied.

In order to reduce the wheelbase distance, the hydraulic cylinder 29 may be extended in the opposite manner to the above. The support arm 20 now pivots rearward about the longitudinal axis 19, so the wheelbase becomes smaller.

In response to the slope of the ground, the swing frame 12 swings about the center axis 13,14.

Furthermore, by moving the steering arm 26 left and right, the left and right front wheels 5 can be steered around the king pin 23.

The support arm 20 and the transmission shaft 36 may be arranged in a front-to-back relationship as described above, or may be arranged one above the other as shown in FIG. 4.

In addition, since the embodiment shows the front wheel 5 side, the tie rod 25 is also used as a part of the parallel link mechanism 28, but if it is adopted for the rear wheel 6, two support arms 20 may be provided in the front and rear. The driving means may be of a screw type.

(Effects of the Invention) According to the present invention, the wheelbase distance can be easily and easily adjusted by rotating the parallel link mechanism around the vertical axis using the driving means, and the operation is smoother than that of a telescoping type. It is also advantageous in terms of strength. Furthermore, the wheelbase can be adjusted, allowing you to use it according to the conditions.

[Brief explanation of drawings]

Fig. 1 is a plan view of essential parts showing one embodiment of the present invention, Fig. 2 is a cross-sectional side view of the same, Fig. 3 is a plan view of the whole, and Fig. 4 is a cross-sectional rear view showing another embodiment. It is. DESCRIPTION OF SYMBOLS 1... Tractor body, 5... Front wheel, 12... Swing frame, 20... Support arm, 25... Tie rod, 28... Parallel link mechanism, 29... Hydraulic cylinder.

Claims (1)

[Claims] 1. A pair of left and right parallel link mechanisms 28 protruding left and right outward from the vehicle body 1 are pivoted to the vehicle body 1 side by a vertical shaft 19, and a wheel 5 is attached to the outer end side of each parallel link mechanism 28.
A wheel length adjustment device for a vehicle, characterized in that a drive means 29 is provided for rotating each parallel link mechanism 28 about the vertical axis 19.