Claims:We claim:

1. A light-weight steering cylinder mounting arrangement for a power-steering axle comprising:

• a box-type axle;
• a pair of wheels mounted on respective wheel discs;
• a steering cylinder assembly; and
• a mounting bracket for mounting the steering cylinder on the steering axle;

wherein the steering cylinder mounting bracket is configured of at least one piece of hot-rolled structural steel, preferably a metal plate having yield strength of at least 350 MPa and ultimate strength of at least 490 MPa and configured to withstand a hydraulic pressure of at least 80 bar.

2. Steering cylinder mounting arrangement as claimed in claim 1, wherein the steering mounting bracket is configured in a C-profile of single piece.

3. Steering cylinder mounting arrangement as claimed in claim 2, wherein a respective reinforcement plate is welded on either side of the inner C profile thereof.

4. Steering cylinder mounting arrangement as claimed in claim 1, wherein the steering mounting bracket is configured in C-profile made of two pieces.

5. Steering cylinder mounting arrangement as claimed in claim 4, wherein a respective reinforcement plate is welded on either side of the inner C profile thereof.

6. Steering cylinder mounting arrangement as claimed in anyone of the claims 1 to 5, wherein the steering mounting bracket supports the central sleeve as well as the steering cylinder of the steering axle.

7. Steering cylinder mounting arrangement as claimed in anyone of the claims 1 to 6, wherein the steering mounting bracket is welded with the central sleeve as well as the central box of the steering axle.

8. Steering cylinder mounting arrangement as claimed in anyone of the claims 1 to 7, wherein the steering mounting bracket configured in C-profile comprises flanges directed outwards for welding on the steering axle box.

9. Steering cylinder mounting arrangement as claimed in anyone of the claims 1 to 8, wherein the steering mounting bracket is configured with at least one rib welded on the corners on either side of the C profile and disposed between the respective flange and the C-profile thereof.

10. Steering cylinder mounting arrangement as claimed in anyone of the claims 1 to 9, wherein the steering mounting bracket comprises a plurality of nuts welded on the longitudinal inner side of the C-profile for fastening of steering cylinder mounting supports.

Dated: this day of 11th April, 2016. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT , Description:FIELD OF INVENTION

The present invention relates to steering arrangement for farm equipment, such as tractors. In particular, the present invention relates to a steering cylinder mounting arrangement for tractors. More particularly, the present invention relates to a steering cylinder mounting arrangement for the power steering front axle of the tractors.

BACKGROUND OF THE INVENTION

The conventional steering arrangement consists of turning the front wheels of farm equipment, such as tractors by using hand operated steering wheel positioned in front of the drive. It is actuated via a steering column containing a pair of universal joints to facilitate a deviation from a straight line, wherever required. The main purpose of a steering arrangement is to point the wheels in the desired direction and this arrangement includes a series of linkages, rods, pivots and gears. The primary concept uses the caster angle, wherein each wheel is steered with a pivot point ahead of the wheel for making the steering to attempt to self-center towards the direction of travel of the tractor.

The typical steering linkages connecting the steering box and the wheels conforms to a variation of Ackermann steering geometry (Figure 1a), whereby while turning, the inner wheel of the tractor is actually travelling a path of smaller radius than the outer wheel. Thus, the degree of toe suitable for driving in a straight path is not suitable for turns. The angle which the wheels make with their vertical plane as well as tyres also substantially affects the steering dynamics (camber angle).

The tractor front axle is particularly suitable for applications, such as primary and secondary tillage in dry land (Ploughing, Rotary tilling, Harrow etc.), inter-culture operations in row crops such as cotton, sugarcane, soya bean etc. and shallow puddling with Rotavator in wet land for rice cultivation. It is also used in orchards and vineyards for spraying. It is equally effectively used in wheel threshing, reaper and seed-cum-fertilizer applications.
DISADVANTAGES WITH THE PRIOR ART

Normally, solid blocks are welded on the tractor front axle for mounting a steering cylinder. However, these solid blocks do not enhance the stiffness of the axle. For single-piece axle (box dimension less than 60 mm width x 60 mm height), the solid block concept does not work, because of serious space constraints and issues related to packaging and/or fouling. Moreover, the solid blocks also add considerable amount of weight to the front axle.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide a simple steering cylinder mounting arrangement for the tractor front axle capable of withstanding higher hydraulic pressure.

Another object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding horizontal accidental impact on both the wheels thereof.

Still another object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding the bump stop.

Yet another object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle which meets the pit-test requirements for single wheel horizontal impact.

A further object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding the torture track loading.

Still further object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding the vertical bending test in fatigue lab.
Yet further object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding the steering forces acting thereon during the left and right hand full-turning.

One more object of the present invention is to provide a steering cylinder mounting arrangement for the tractor front axle capable of withstanding the steering forces acting thereon in straight wheel stuck-up condition.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a steering cylinder mounting arrangement comprising: a light-weight steering cylinder mounting arrangement for a power-steering axle comprising:
• a box-type axle;
• a pair of wheels mounted on respective wheel discs;
• a steering cylinder assembly; and
• a mounting bracket for mounting the steering cylinder on the steering axle;

wherein the steering cylinder mounting bracket is configured of at least one piece of hot-rolled structural steel, preferably a metal plate having yield strength of at least 350 MPa and ultimate strength of at least 490 MPa and configured to withstand a hydraulic pressure of at least 80 bar.

Typically, the steering mounting bracket is configured in a C-profile of single piece.

Typically, a respective reinforcement plate is welded on either side of the inner C profile thereof.

Typically, the steering mounting bracket is configured in C-profile made of two pieces.
Typically, a respective reinforcement plate is welded on either side of the inner C profile thereof.

Typically, the steering mounting bracket supports the central sleeve as well as the steering cylinder of the steering axle.

Typically, the steering mounting bracket is welded with the central sleeve as well as the central box of the steering axle.

Typically, the steering mounting bracket configured in C-profile comprises flanges directed outwards for welding on the steering axle box.

Typically, the steering mounting bracket is configured with at least one rib welded on the corners on either side of the C profile and disposed between the respective flange and the C-profile thereof.

Typically, the steering mounting bracket comprises a plurality of nuts welded on the longitudinal inner side of the C-profile for fastening of steering cylinder mounting supports.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1a shows a typical Ackerman steering geometry for a tractor’s front axle.

Figure 1b shows a typical line diagram for steering movement depicting the tractor’s front axle in the right-most position thereof.

Figure 1c shows a typical line diagram for steering movement depicting the tractor’s front axle in the left-most position thereof.

Figure 2 shows a perspective view of the conventional front-axle steering cylinder mounting arrangement in a tractor having solid blocks.

Figure 3 shows an enlarged view of one of the solid blocks depicted in Fig.2.
Figure 4 shows a top view of steering cylinder mounting arrangement configured in accordance with the present invention fitted on the tractor front-axle assembly depicted without wheels.

Figure 5 shows an enlarged view of the hydraulic cylinder connected between two eye bolts depicted in Figure 4.

Figure 6 shows a perspective view of the steering cylinder mounting arrangement configured in accordance with the present invention fitted on the tractor front-axle assembly.

Figure 7 shows a perspective view of the steering cylinder mounting arrangement configured in accordance with the present invention and fitted on tractor front-axle assembly and disposed under the semi-chassis.

Figure 8 shows another perspective view of the steering cylinder mounting arrangement fitted with the hydraulic cylinder on tractor front-axle assembly.

Figure 8a and 8b shows a perspective view of the steering cylinder mounting bracket configured in one piece and two pieces respectively.

Figure 8c and 8e show top views of the steering cylinder mounting bracket configured in one piece and two pieces respectively.

Figure 8d and 8f show top views of the steering cylinder mounting bracket configured in one piece with a plurality of nuts welded thereon. In this configuration, a plurality of ribs R is also welded at the corners to increase the strength of the axle.

Figure 9 shows the front view of the steering cylinder mounting arrangement configured in accordance with the present invention fitted on tractor front-wheel assembly.

Figure 10 shows an enlarged cross-sectional view across section line X – X in Figure 4 depicting the left-hand side view of the front-axle assembly fitted with the steering cylinder mounting arrangement fitted under the semi-chassis.

Figure 11 shows a steering mounting bracket welded with the central sleeve and the center box 10 construction in single piece.

Figure 12 shows a comparative graph for the stress under different load conditions in the conventional block type steering cylinder mounting bracket and the steering cylinder mounting bracket configured in accordance with the present invention.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1a shows a typical Ackerman steering geometry for a tractor’s front axle 10 with reference to its rear axle 20. The geometric arrangement of linkages in the steering of a vehicle avoids the requirement of tracing out the circles of different radii R1, R2 on the inside and outside while turning around a curve and so the tyres do not need to slip sideways. Here, all wheels 11, 12, 21, 22 have their axles arranged as radii of circles with a common centre point C. Since the rear wheels 21, 22 are fixed, this centre point C is kept be on a line extended from the rear axle 20. Intersecting the axes of the front wheels 11, 12 on this line requires the inside front wheel 11 turns by a greater angle than the outside wheel 12 while it is steered. In contrast to the earlier known "turntable" steering, in which both front wheels were turned around a common pivot, here, each wheel 11, 12 gains its own pivot close to its own hub. A linkage between these hubs pivots the two wheels together, and by careful arrangement of the linkage dimensions the Ackermann geometry could be approximated. This was achieved by making the linkage the length of the track rod 30 (the moving link between the hubs 31, 32) shorter than that of the front axle 10, so that the steering arms 33, 34 of the hubs 31, 32 "toe out". On turning the steering, the wheels 11, 12 also turned according to Ackermann geometry, with the inner wheel 11 turning more than outer wheel 12. This arrangement enhances controllability by compensating for the road surface variations applied to the end of a long lever arm and also substantially reduces the fore-and-aft travel of the steered wheels 11, 12 on the front axle.

Figure 1b shows a typical line diagram for steering movement depicting the tractor’s front axle in the right-most position thereof. The track rod 30 is moved leftwards with respect to the longitudinal axis of the vehicle. In this position, the steering arm 33 makes a smaller angle ?1 with respect to the axis of the left wheel 11 than the angle ?2 made by the steering arm 34 with respect to the axis of the right wheel 12. This lateral movement of the track rod 30 is accomplished by means of the steering cylinder mounted on the front axle by means of the steering cylinder mounting arrangement discussed below.

Figure 1c shows a typical line diagram for steering movement depicting the tractor’s front axle in the left-most position thereof. The track rod 30 is moved rightwards with respect to the longitudinal axis of the vehicle. In this position, the steering arm 33 makes a greater angle ?1 with respect to the axis of the left wheel 11 than the angle ?2 made by the steering arm 34 with respect to the axis of the right wheel 12.

Figure 2 shows a perspective view of the conventional front-axle steering cylinder mounting arrangement in a tractor having solid blocks on either side of the center sleeve 16. The front axle 10 is of box-type single-piece construction with solid blocks 18 welded thereon for mounting the steering cylinder, however, which do not improve the stiffness of the axle 10. It is also observed that when the axle 10 has box dimensions of less than 60 mm width x 60 mm height, then due to space constraints and for reasons of packaging and fouling, this solid box construction is ineffective. Moreover, these solid blocks 18 also significantly increase the weight of the front axle 10.

Figure 3 shows an enlarged view of one of the solid blocks 18 fitted on the axle 10 as depicted in Fig.2.

Figure 4 shows a top view of the steering cylinder mounting arrangement configured in accordance with the present invention fitted on a two-wheel drive tractor’s front-wheel assembly depicted without wheels. The front axle 10 is fitted with a pair of wheel discs 13, 14 and eye bolts 35, 37 each on the left-had and right-hand side thereof. The steering mounting bracket 36 is disposed in the middle of the axle 10 with the center sleeve 16 passing therethrough. The bracket 36 is made of a metallic plate and thus is simple in design and also substantially reduces the overall weight of the axle with respect to the earlier block type construction.

Figure 5 shows an enlarged view of the hydraulic cylinder 39 connected between two eye bolts 35, 37 of the front axle 10 depicted in Figure 4.

Figure 6 shows a perspective view of the steering cylinder mounting arrangement configured in accordance with the present invention. The steering mounting bracket 36 includes a hole for passage of center sleeve 16 therethrough. The bracket 36 is fitted on the tractor front-axle 10 assembled with wheel discs 13 and 14 for assembly of tyres or wheels 11, 12 on either side, which are each connected to eye bolts 31, 32 with connecting tie rod assemblies at respective knuckle arms to be attached to the hydraulic cylinder (not shown). A pair of piston rod guards 42, 44 is also shown disposed on either side of the front axle 10.

Figure 7 shows a perspective view of the steering cylinder mounting arrangement of Figure 6 fitted on tractor front-axle assembly disposed under the semi-chassis 40. The pivot pin 17 is fixed by means of a plurality of fasteners 19 on the pillow block PB mounted on the steering mounting bracket 36 and with the central sleeve 16 passing therethrough.

Figure 8 shows another perspective view of the steering cylinder mounting arrangement fitted on the tractor front-axle assembly, which is similar to Figure 7, however, fitted with the hydraulic cylinder 50. Normally, the bracket 36 is made of a hot rolled structural steel, preferably having the yield strength of about 350 MPa and an ultimate strength of about 490 MPa as per the Indian standard IS 2062 specified for hot rolled medium/high tensile structural steel.

Figure 8a shows a perspective view of the steering cylinder mounting bracket 36 configured in one piece 36A and includes hole 15 for the passage of the center sleeve 16.
Figure 8b shows a perspective view of the steering cylinder mounting bracket 36 configured in two pieces 36B1, 36B2 and it also includes hole 15 for the passage of the center sleeve 16.

Figure 8c shows a perspective view of the steering cylinder mounting bracket 36A configured in one piece. It includes a plurality of nuts N welded thereon.

Figure 8d shows a perspective view of the steering cylinder mounting bracket 36A configured in one piece. In this configuration, a plurality of ribs R is also welded at the outer corners to increase the strength of the axle.

Figure 8e show the perspective view of the steering cylinder mounting bracket configured in two pieces (36B1, 36B2) and a plurality of nuts N are welded on the inner flange thereof.

Figure 8f shows the perspective view of the steering cylinder mounting bracket configured in two pieces 36B1, 36B2 and a plurality of nuts N are also welded on the inner flange thereof. It also includes ribs R is welded at the outer corners to increase the strength of the axle.

Figure 9 shows the front view of the complete steering cylinder mounting arrangement configured in accordance with the present invention fitted on tractor front-wheel assembly. The steering mounting bracket 36 is fitted on the front axle 10 carrying wheels 11 and 12 on LHS and RHS respectively. The hydraulic cylinder 50 is fitted between the eye bolts 31 and 32 respectively. A central sleeve 16 passes through the pillow block PB mounted on the steering mounting bracket 36. The complete wheel assembly equipped with the steering mounting arrangement according to the invention is centrally fitted under the semi-chassis 40 about the axis X - X.

Figure 10 shows an enlarged cross-sectional view across section line X – X in Figure 9 depicting the left-hand side view of the front-axle assembly fitted with the steering cylinder 50 connected to the eye bolt 31. The complete arrangement is fitted on front axle 10 and is disposed under semi-chassis 40.

Figure 11 shows a steering mounting bracket 36 joined to the central sleeve 16 and the center box 10 by means of welded joints W throughout the joint.
Figure 12 shows a comparative graph for the stress under different load conditions (1, 2, 3, 4, 5, 6 and 7 described below) in the conventional block type steering cylinder mounting bracket and the steering cylinder mounting bracket configured in accordance with the present invention. The data concerns seven different types of loads experienced by the steering cylinder mounting bracket of the conventional type and configured according to the present invention. These loads (MPa) and the comparative data collected are also tabulated as given below:

S. No. Load Case Stress (MPa) % Stress Reduction
Conventional Block type Bracket Inventive Plate type Bracket
1 Both wheel horizontal (accidental) impact 1190 507 57.4
2 Bump stop 537 495 7.8
3 Pit-test – One wheel horizontal impact 1250 500 60
4 Torture track 338 319 5.6
5 Fatigue lab vertical
bend-test 219 262 - 16.4
6 LH/RH full turn –
Steering force (SEL lab) 743 335 54.9
7 Steering force (Straight wheel stuck-up condition) 695 306 55.9

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The steering cylinder mounting arrangement configured in accordance with the present invention has the following advantages:

• Simple construction capable of withstanding higher hydraulic pressure up to 80 bar.

• Capable of withstanding horizontal accidental impact on both the wheels thereof.

• Capable of withstanding the bump stop.
• Satisfies the pit-test requirements for single wheel horizontal impact.

• Capable of withstanding the torture track loading.

• Capable of withstanding the vertical bending test in fatigue lab.

• Capable of withstanding the steering forces acting thereon during the left and right hand full-turning.

• Capable of withstanding the steering forces acting thereon in straight wheel stuck-up condition.

• Can be implemented in both single-piece as well as 3-piece front axle.

• Supports the steering cylinder as well as the center sleeve of the axle.

• Durability of axle increases due to integration with center sleeve.

• Raw material cost can be saved up to 50%.

• Ribs on either side of cylinder mounting bracket increases the axle strength by 20%

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The description provided herein is purely by way of example and illustration. The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples. However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description. Therefore, innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

The exemplary embodiments were selected and described in order to be able to best represent the principles and their possible practical application underlying the invention. Thereby, the skilled persons can optimally modify and use the invention and its different exemplary embodiments with reference to the intended use.