Patent Application
20070245845
1. Field of the Invention
The present invention relates to a steering column assembly for a vehicle and more particularly to an adjustable steering column assembly.
2. Description of Related Art
Steering column assemblies are know to have a rotating shaft connected at one end to a steering wheel and at an opposite end supported by a bracket carrying a bearing race for smooth rotation of the shaft. The rotating shafts typically have a non-rotating jacket sleeve co-extending concentrically with the rotating shaft and spaced radially outward therefrom. For steering column assemblies known to have a tilt adjustment feature, the bracket is support pivotally by a vehicle structure. The pivot joint carried between the bracket and structure has many individual parts and are known to include a separate pin or bolt that must be threaded through a series of holes in both the bracket and the structure. The bolt is secured in place by a threaded nut and a series of washers along its length. Unfortunately, the numerous parts and time consuming assembly of the joint increases manufacturing costs.
Moreover, and particularly for telescoping shaft applications, the jacket sleeve must be rigidly engaged to the bracket so that it is held stationary relative to the shaft and regardless of the steering wheel's tilted position. Typically, a plurality of pins or threaded fasteners with corresponding holes in both the sleeve and the bracket are used to fasten the sleeve to the bracket. The excessive parts again leads to relatively high manufacturing costs.
An adjustable steering column assembly for a vehicle has an integral rake pivot joint carried between a mounting structure generally attached to the vehicle chassis and a support bracket that pivots about a pivot axis. A preferably telescoping shaft extends along a centerline and connects to a steering wheel at a first end and is rotationally supported near an opposite second end by the support bracket. Preferably, the pivot axis is orientated substantially parallel to the centerline. The pivot joint has a boss preferably elongated with respect to the pivot axis and generally orientated concentrically to the pivot axis. The boss fits pivotally in a bore disposed concentrically to the pivot axis and carried by the other of the mounting structure and support bracket. A web portion of the boss projects through a slit extending axially and communicating radially inward with the bore.
Preferably, the support bracket has a through-bore disposed concentrically to the centerline through which the telescoping shaft extends and the second end of the shaft projects in a forward direction with respect to the vehicle. A bearing adaptor fits into a forward portion of the through bore for rotatably supporting the second end of the telescoping shaft. Preferably, a rearward projecting jacket sleeve of the steering column assembly snap fits into a rearward portion of the through-bore and projects concentrically rearward along the centerline with the rotating shaft spaced radially inward.
Objects, features and advantages of the present invention include an adjustable steering column assembly having self lubricating rake pivot joint that is integrated into existing structures. This, and the snap fitting jacket sleeve reduce the number of parts otherwise required for assembly and simplify the assembly process of the steering column assembly. Other advantages include a robust design requiring little or no maintenance and in service has a long and useful life.
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, an adjustable steering column assembly 20 used for a vehicle and embodying the present invention and for a vehicle, has a tilt feature and preferably a telescoping feature that adjusts positioning of a steering wheel (not shown) for driver convenience and comfort. As best illustrated in
The mounting structure 22 of the steering column assembly 20 is preferably fastened to a chassis or underneath a dash of the vehicle by a plurality of threaded fasteners or bolts (not shown) and preferably with respective bushings located between the chassis and structure 22 to reduce the amount of vibration that could otherwise be transmitted to the steering column assembly 20. The structure 22 is generally U-shaped having two substantially parallel legs 40, 42 projecting rearward and substantially horizontally from a base member 44 that pivotally connects to the support bracket 24. A generally U-shaped housing 45 of the support mechanism 36 is orientated in an upright position and has two parallel walls 47, 49 that hang or are connected to the respective legs 40, 42 of the mounting structure 22. The telescoping shaft 26 and the sleeves 32, 34 extend through the housing 45 between the walls 47, 49 and lie substantially parallel to and at least in part below the legs 40, 42.
As best illustrated in
As best illustrated in
The front sleeve 32 is preferably substantially cylindrical having an outer diameter that is slightly less than an inner diameter of the rear sleeve 34 (i.e. rearward with respect to the vehicle). A forward end 28 of the front sleeve 32 has a continuous peripheral edge 64 and preferable four recesses or holes 66 located rearward of the edge 64. The holes 66 are opened at least radially inward and spaced circumferentially about the sleeve 32 to align with the enlarged heads 62 of the lock arms 60 when the front sleeve 32 is snap fitted to the support bracket 24.
A rack pivot joint 68 pivotally engages the support bracket 24 to the base member 44 of the mounting structure 22 and about the pivot axis 46. Preferably, the pivot joint 68 does not have any dedicated individually separated parts, and instead is completely integrated and carried between the support bracket 24 and the base member 44. As best shown in
The boss 70 has a substantially cylindrical pin 72 disposed concentrically to the pivot axis 46 and a co-extending web 74 that projects laterally outward from a substantially planar exterior face 76 carried by the support bracket 24 and located above the through-bore 48. The pin 72 carries a substantially cylindrical convex surface 78 that is contiguous to the exterior face 76 at the web 74. The convex surface 78 angularly extends circumferentially about the pivot axis 46 by an amount greater than one-hundred and eighty degrees from one side of the web 74 to the other.
During assembly, the pin 72 of the boss 70 is received in a bore 80 of the rack pivot joint 68 in the base member 44 of the mounting structure 22 (see
The convex surface 78 of the pin 72 preferably defines at least one axial extending groove 88 that distributes lubricant between surfaces 78, 86 for substantially friction-free pivoting. To prevent the support bracket 24 from falling out of the bore 80 in the base member 44 of the mounting structure 22, the concave surface 86 extends circumferentially at a greater angular distance than the convex surface 78 of the pin 72 of the boss 70. Preferably, the support bracket 24 and thus the steering wheel is constructed to pivot or tilt by an amount of about fifteen degrees. The width of the slit 84 must therefore be greater than the thickness of the web 74 by a circumferential distance equating to greater than fifteen degrees.
The support bracket 24 is preferably made of injection molded plastic and as one unitary piece with the resilient lock arms 60. The front sleeve 32 is preferably made of metal for rigidity. One skilled in the art would now know that various elements of the invention can be reversed. For instance, the boss 70 of the rake pivot joint 68 could be in the support bracket 24 and the boss 70 formed to the mounting structure 22. Moreover, the boss 70 need not have an elongated pin 72 but instead could carry an enlarged and generally spherical head thus altering the pivot axis 46 to a pivot point.
Referring to
As best illustrated in
So that the pin 72′ of the boss 70′ can be inserted radially into the bore 80′, the radial distance 108 of the pin 72′ is preferably slightly less than a width 110 of the slit 84′ of the bore 80′. Alternatively, the radial distance 108 could be equal to or even slightly greater than the width 110 thus enabling a snap fit engagement. However, any such snap fit engagement should not cause plastic deformation of either the structure 22′ or the bracket 24′ that could potentially hinder pivotal movement.
When the steering column assembly 20′ pivots between the tilt down and tilt up positions 94, 96, the bracket 24′ pivots at a maximum angular displacement, represented as arrow 112 in
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. For instance, orientation of components with respect to the vehicle can be changed from “forward” and “rearward” to “lower” and “upper”. As is now apparent to those skilled in the art, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.
