FIELD OF INVENTION

[0001] The present invention relates to the field of automotive engineering, more particularly steering assemblies for use in the modification of left hand drive vehicles using rack and pinion steering to right hand drive.

[0002] In one form, the invention relates to a device and method for orienting the pinion relative to the rack and steering column and is suitable for use in the conversion of vehicles using rack and pinion steering from left-hand drive to right-hand drive (and vice versa)

[0003] It will be convenient to hereinafter describe the invention in relation to utility trucks, however it should be appreciated that the present invention is not limited to that use only and has a much wider range of applications in the automotive industry.

BACKGROUND ART

[0004] It is to be appreciated that any discussion of documents, devices, acts or knowledge in this specification is included to explain the context of the present invention. Further, the discussion throughout this specification comes about due to the realisation of the inventor and/or the identification of certain related art problems by the inventor. Moreover, any discussion of material such as documents, devices, acts or knowledge in this specification is included to explain the context of the invention in terms of the inventor's knowledge and experience and, accordingly, any such discussion should not be taken as an admission that any of the material forms part of the prior art base or the common general knowledge in the relevant art in Australia, or elsewhere, on or before the priority date of the disclosure and claims herein.

Automotive Steering Assembly

[0005] An automotive steering assembly allows the driver to control the direction in which the vehicle travels. The steering assembly, in some vehicles, includes: (i) Mechanical components which are designed to respond to a driver moving the steering wheel of the vehicle, such as steering column, rack and pinion assembly, tie rods which transmit motion to the vehicle (front) wheels, as well as numerous other mechanical components, and.

(ii) Electronic components, such as an electronic controller for the steering assembly, electric motors and various signalling components to interface with the vehicle electronic displays and computers.

Drive Conversion

[0006] Vehicles are manufactured in either left-hand drive or right-hand drive steering configurations, the terms 'left' and 'right' referring to the placement of the driving seat and controls within the vehicle relative to a person sitting inside the vehicle. Most countries have legislation that dictates whether cars in the relevant jurisdiction are left- hand or right-hand drive and it is common for imported cars to have steering conversion to comply with local law. Typically, countries in which cars drive on the left side of the road use right-hand drive vehicles, and countries in which cars drive on the right side of the road countries use left-hand drive vehicles.

[0007] The inventors have realised that the overall exterior appearance of most vehicles, particularly the chassis, is relatively symmetrical about the longitudinal axis. However, this is not true of most of the interior mechanical fittings due to the placement of driving controls on the left or the right hand side of the vehicle. The lack of symmetry is particularly inconvenient when a vehicle is changed from left-hand to right-hand drive or vice versa because it is not necessarily possible to simply rotate components and re-fit them. Often they must be extensively re-engineered and re-positioned.

[0008] For example, large numbers of left-hand drive utility trucks are manufactured in the United States of America. The market for right-hand versions of these utility trucks is too small to justify manufacturing any as right-hand drive vehicles. Accordingly, when the left-hand drive utility trucks are exported to countries such as Australia and New Zealand, they must be converted to right-hand drive to comply with local law. [0009] The inventors have further realised that to facilitate the modification of OEM built left hand drive vehicles with rack and pinion steering to right hand drive vehicles with rack and pinon steering requires the replacement in whole or in part of the OEM steering componentry. This process requires use of componentry designed specifically for right hand drive or to enable the interface of the OEM's left hand drive componentry to function in right hand drive configuration. This involves making parts from scratch because they are not available from the manufacturer. The need to manufacture parts tends to make the steering conversion very expensive.

[0010] The inventors have realised that this change from left-hand to right-hand drive raises particular problems with respect to steering assemblies. The steering assembly is not only of asymmetric shape, but must fit within the confines of the chassis and engine bay. In particular, there are a number of structural and safety elements that cannot be moved during the drive conversion because this would compromise the safety of the vehicle.

[0011] In particular, many larger vehicles such as utility or pick-up trucks and SUVs have a frame comprising two parallel boxed or C-cross section rails (known as 'chassis rails') and have cross members (which together resemble a ladder type arrangement). Typically a vehicle will have two relatively straight portions of chassis rails positioned down the longitudinal axis of the vehicle. In some vehicles, at either end, the chassis rails are no longer straight, but conform to the curve of the wheel arches. The engine of most modern vehicles takes up most of the space in the engine bay, leaving very little room for maneuvering or repositioning vehicle components. A cross member is also usually positioned in and around the engine bay further limiting the space available for left to right hand side driving conversion.

[0012] Safety is another key consideration when changing a vehicle's steering assembly from one side to the other. Government regulatory requirements for steering conversions from left hand drive to right hand drive typically require that in right hand drive configuration:

(a) The mounting strength and geometry of the OEM's left hand drive steering column is replicated in right hand drive configuration. (b) The features of the left hand drive steering column designed by the vehicle OEM which allow a controlled collapse if the vehicle is involved in a frontal collision must not be affected.

(c) The telescopic sections of the steering column must not be extended or contracted from the OEM left hand drive manufactured specification.

[0013] Due to the aforementioned limitations a rack and pinion assembly for a left- hand drive vehicle often cannot be re-fitted when the vehicle is converted to right-hand drive or vice versa.

SUMMARY OF INVENTION

[0014] An object of the present invention is to provide a device to assist in the changeover of a vehicle from left-hand to right-hand drive or vice versa.

[0015] A further object of the present invention is to alleviate at least one disadvantage associated with the related art.

[0016] It is an object of the embodiments described herein to overcome or alleviate at least one of the above noted drawbacks of related art systems or to at least provide a useful alternative to related art systems.

[0017] In a first aspect of embodiments described herein there is provided a method for converting the drive side of a vehicle including the step of attaching a steering rack and pinion assembly to a front cross member of a vehicle chassis, the cross member having a longitudinal axis and a transverse axis wherein the pinion is provided at an angle of between 70° to 80° to the longitudinal axis and, at an angle of 15° to 25° to the transverse axis of the cross member.

[0018] Typically, the pinion is provided at an angle of 76° to the top (horizontal) surface and 20° to the front (vertical) surface of the front cross member. [0019] The vehicle chassis is a frame that supports the structure of the vehicle. All major vehicle components are attached to the chassis which must be able to deal with static and dynamic loads without undue deflection or distortion. Modern vehicle chassis typically have two chassis rails running the length of the vehicle with cross member(s) located perpendicular to the chassis rails. The steering rack and pinion assembly may be attached to the front cross member and the angle of the pinion in the assembly can be described with reference to the aforementioned two ranges of angles.

[0020] In a particularly preferred embodiment, the method is used for the conversion of a left hand drive vehicle to a right hand drive. Typically, in a vehicle such as an SUV or utility truck, the engine takes up the majority of space in the engine bay. A vehicle originally manufactured for left hand drive will also have a number of its drive related components taking up much of the space in the engine bay and these will not necessarily be moved during a right hand drive conversion. Immovable structural features such as chassis rails and cross member further limit the ability to rearrange elements of the steering rack and pinion assembly. It has been found that in a left hand to right hand drive conversion it may be possible to locate the steering rack and pinion assembly on the right hand side of the vehicle, proximate the space near the engine, adjacent the cross member and between the engine and the chassis.

[0021] In a second aspect of embodiments described herein there is provided a steering rack and pinion assembly comprising:

• A pinion residing within a cylindrical pinion housing having a first longitudinal axis,

• A rack shaft housing having a second longitudinal axis,

• A cross member mounting having a third longitudinal axis, wherein the first and second longitudinal axes are at an angle of between 70° to 80° and the second and third longitudinal axes are at an angle of between 105° and 115°. [0022] Preferably, the first and second longitudinal axes are at an angle of 76° and the second and third longitudinal axes are at an angle of 110°.

[0023] In a third aspect of embodiments described herein there is provided a steering rack and pinion assembly comprising:

• A pinion residing within a cylindrical pinion housing having a first longitudinal axis,

• A rack shaft housing having a second longitudinal axis,

• A cross member mounting having a third longitudinal axis and a transverse axis, wherein the first and second longitudinal axes are at an angle of between 70° to 80° and the second and third longitudinal axes are at an angle of between 15° and 25° relative to the transverse axis of the cross member.

[0024] Preferably, the first and second longitudinal axes are at an angle of 76° and the second and third longitudinal axes are at an angle of 20° relative to a vertically oriented transverse axis of the cross member.

[0025] In a fourth aspect of embodiments described herein the pinion housing maybe aligned substantially co-axial with the pinion.

[0026] In a fifth aspect of embodiments described herein the pinion housing may be oriented generally in the direct of the pinion i.e. mis-aligned and not precisely co-axial, when compared to the pinion orientation.

[0027] The steering rack and pinion assembly may be manufactured by the step of reusing some of the OEM parts, but the assembly may also be formed of newly manufactured components configured according to the present invention. In a fourth aspect of embodiments described herein there is provided a vehicle steering assembly modified according to a method and apparatus as disclosed herein. [0028] The person skilled in the art will appreciate that the angles referred to herein will vary within normal manufacturing tolerances, but no more than 1° in any direction.

[0029] Other aspects and preferred forms are disclosed in the specification and/or defined in the appended claims, forming a part of the description of the invention.

[0030] In essence, embodiments of the present invention stem from the realization that the angle of the pinion shaft can be oriented so as to provide dynamic interface between the steering rack and pinion assembly (which is affixed to the chassis cross member) and the steering column. Furthermore it has been realised that this makes it possible to optimise the position of the steering column for the steering assembly of a drive conversion vehicle, despite space limitations and inherent asymmetry of the vehicle.

[0031] Advantages provided by the present invention comprise the following:

• parts of the OEM steering assembly may be modified and reused, thus avoiding the expense of custom making each component;

• the steering rack and pinion assembly of the present invention can work with the existing, manufacturer installed electronic systems that assist in control of vehicle steering; and

• the pinion orientation in accordance with the present meets dynamic and static clearances required in accordance with vehicle manufacturing regulations;

• enabling the mounting strength and geometry of the OEM's left hand drive steering column to be replicated in right hand drive configuration thus enabling the features of the left hand drive steering column designed by the vehicle OEM which allow a controlled collapse if the vehicle is involved in a frontal collision not being affected and ensuring that the telescopic sections of the steering column must are not extended or contracted from the OEM left hand drive manufactured specification; • the mounting strength and geometry of the OEM's left hand drive steering column is replicated in right hand drive configuration;

• if the vehicle is involved in a frontal collision, the present steering assembly of the present invention is seen to not affect the controlled collapse of the steering column (as built in left hand drive configuration) and facilitate the telescopic sections not extending or contracting beyond the OEM left hand drive manufactured specification;

• In the event of a frontal collision, the steering assembly of the present invention is designed to collapse substantially in a direction outward of the engine bay of the vehicle and away from the driver and passenger of the vehicle.

[0032] Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which:

[0034] List of parts referred to in the illustrations: I Pinion end housing 2 Ballscrew end housing

3 Pinion

5 Ballscrew rackshaft 6 Encoder lid

7 Encoder housing 8 Motor

9 Bush liner 10 Neoprene bush

I I Threaded bush liner 12 Bronze bushing

13 Nutblock 14 Adjuster bush

15 Internal circlip 16 Pinion housing

18 Nutblock bearing

19 Nutblock securing nut 20 O-ring

22 Left chassis rail

23 Right chassis 24 Engine cross member

25 Front cross member 26 Right suspension bracket

27 Left suspension bracket 28 Rack shaft Housing

29 rack mounting point

FIG. 1 illustrates a top plan view illustrating a vehicle steering assembly according to the present invention;

FIG. 2 illustrates a view of a typical vehicle chassis of the type to which the steering assembly of FIG. 1 would be fitted;

FIG. 3 illustrates a first detailed view of the steering rack shaft and pinion housing of FIG. 1 ;

FIG. 4 illustrates a second detailed view of the steering rack shaft and pinion housing of FIG. 1 ;

FIG. 5 illustrates a third detailed side view of the steering rack shaft and pinion housing; and

FIG. 6 illustrates another view of the vehicle steering assembly according to the present invention. DETAILED DESCRIPTION

[0035] FIG. 1 shows the various parts of a steering assembly according to the present invention. Particular regard is to be had to the angle of the pinion shaft, the orientation of which provides a dynamic interface between the steering rack assembly and the steering column.

[0036] FIG. 2 is a view of a typical vehicle chassis of the type used in utility trucks such as a Ford F-150. For purposes of description herein, the terms "upper," "lower," "right," "left," "rear," "front," "vertical," "horizontal," "interior," "exterior," and derivatives thereof shall relate to the orientations depicted in FIG. 2 and with reference to the x, y and z axes depicted therein.

[0037] This type of ladder frame chassis has a left chassis rail (22) and a right chassis rail (23) which extends in the direction of the z-axis. A front cross member (25) is perpendicular to the chassis rails (22,23), extending in the direction of the x-axis for mounting of the steering assembly of FIG. 1 . The front cross member is located in front of the engine cross member (24. Utility trucks typically have large engines, such as 6 cylinder or V-8 engines which take up much of the vehicle engine bay. It is important that the steering column of the steering assembly passes between the engine and the fixed suspension brackets (26,27) and/or other body panel components (not shown) without any points of contact.

[0038] FIG. 3 , FIG. 4 and FIG 5 are detailed views of different aspects the rack shaft and pinion housing of FIG. 1. As shown in FIG. 4, the rack shaft and pinion housing is attached to the front cross member (25) of FIG. 2 in a manner that the pinion (16) is provided at an angle (a ⁰ ) of between 70° to 80°, preferably 76° relative to the longitudinal axis (in the x-axis direction) of the front cross member and, as shown in FIG. 5 the pinion is at an angle (c°) of between 15° to 25°, preferably 20° relative to the vertical transverse axis d . In referring to FIG. 3, the angle (c°) is b° - 90° from the transverse axis (in the y-direction) of the front cross member 25. [0039] So, in one embodiment, when the front cross member 25 is of square cross section, the pinion will be at an angle of 76° to the top (horizontal) surface and 20° to the front (vertical) surface of the cross member 25.

[0040] From FIG. 3 and FIG. 4 it can be seen that the steering rack shaft and pinion housing comprises a pinion (3) residing within a cylindrical pinion housing (16) having a first longitudinal axis, a rack shaft housing (28) having a second longitudinal axis, and a cross member mounting (29) having a third longitudinal axis. The first and second longitudinal axes are at an angle of between 70° to 80°, preferably 76° and the second and third longitudinal axes are at an angle of between 105° and 115°, preferably 110°.

[0041] FIG. 6 illustrates another view of the vehicle steering assembly according to the present invention. As shown in FIG. 6, the pinion 3 is oriented at an angle (a ⁰ ) of between 70° to 80°, preferably 76° relative to the longitudinal axis e of the steering assembly. Preferably, when fitted to the vehicle, the axis e corresponds to the longitudinal x-axis of the cross member as shown in FIG. 2

[0042] It is also to be understood that the specific devices and processes illustrated in the attached drawing, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless otherwise specified, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like does not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified.

[0043] While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to ]

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which the invention pertains and as may be applied to the essential features hereinbefore set forth.

[0044] As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. The described embodiments are to be considered in all respects as illustrative only and not restrictive.

[0045] Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures.

[0046] "Comprises/comprising" and "includes/including" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Thus, unless the context clearly requires otherwise, throughout the description and the claims, the words 'comprise', 'comprising', 'includes', 'including' and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".