Title of Invention

IMPROVED VEHICLE DIFFERENTIAL GEAR WITHOUT DIFFERENTIAL CASE

Abstract

A motor vehicle differential gear assembly for transferring rotational torque input by a hypoid pinion drive gear rotatably driven by a transmission output shaft to a pair of substantially axially aligned rotary driven axle shafts that are journaled for rotation, the differential gear assembly of the type having a hypoid ring gear journaled for rotation concentrically with respect to axle shafts and meshing with hypoid pinion drive gear and differential pinion gears mounting a cross spider rotatable with the hypoid ring gear and further meshing with side gears coupled to vehicles axle shafts, said assembly comprising: a hypoid ring gear having an inner and an outer surface and having four evenly spaced threaded bores on the backside and forming four evenly spaced grooves onto the inner surface, the grooves are evenly spaced onto the inner surface of the hypoid ring gear opening laterally to receive the cross spider stub shafts, the grooves extend laterally from backside of the hypoid ring gear and terminating just before front teeth base;

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See section 10; rule 13) 1. "Improved vehicle differential gear assembly without differential case" 2. (a) Taiyebi Quresh Abdulkader (b)B7-402, Bramha Majestic NTBM Road, Kondhwa Khurd Pune 411 048 Maharashtra INDIA (c) of INDIAN nationality The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed: - As per attached sheets GRANTED 17-11-2005 IMPROVED VEHICLE DIFFERENTIAL GEAR WITHOUT DIFFERENTIAL CASE The present invention relates to an automobile differential gear assembly and more particularly to four spider gears rotatably mounted on stub shafts of a cross spider that is supported directly into grooves within a ring gear. In a differential gear assembly of an automotive vehicle, output drive shaft of a vehicle is rigidly fixed to a hypoid pinion drive gear, which is in constant mesh with a hypoid ring gear that is bolted to an annular flange formed on outer periphery of a differential casing that is journaled for rotation relative housing. Ring gear and differential casing rotate coaxially between a pair of side gears mounted onto a pair of spttned proximate ends of axle shafts that are journaled for rotation onto a pair of anti-friction bearings. A pair of spider gears is rotatably mounted onto a differential pin that passes through differential casing diametrically. The rotational load from transmission output drive shaft to drive pinion gear causes ring gear and differential case rotate coaxially that in turn causes side gears to rotate axle shafts and wheels of vehicle. Therefore, differential case must be designed with such structural integrity as to support loads being transferred. The required strength, however, typically requires a relatively large axle housing, which is heavy, bulkier and expensive. As such, there is a need for an axle housing, which can be designed with total elimination of differential case while reducing dimension, weight and cost thereof. U.S. Pat. Nos.6,652,408 and 6,743,138 are illustrative of axle housing of this type. While the former merely describes the differential gear with ring gear directly loading the differential pin, the later describes the similar arrangement providing the rotatable support to the ring gear by a pair of roller bearings positioned between the inwardly facing annular surfaces of the ring gear and the outwardly facing annular surfaces of axle housing. However, supporting the ring gear in such a way is not sufficient enough to overcome the strong opposing forces that work while the machine is in motion. Therefore, the present invention provides the substantial axial and radial support ami alignment to the hypoid ring gear, having the cross spider shaft disposed directly into grooves on the inner periphery thereof in tile form of a pair of roller bearings that are disposed into either side of central block portion of cross spider shaft and that are joumaled onto the elongated proximate ends of axle shafts According to this invention, a new improvement is proposed in an automobile axle housing, wherein power is transmitted from output shaft to side gears that are in mesh with a plurality of spider gears (four in this invention) rotatably mounted onto stub shafts of a cross spider disposed into grooves provided within inner periphery of a ring gear. The assembly of cross spider and spider gears is retained into grooves by an annular plate fixed to backside of a hypoid ring gear by suitable fasteners. The cross spider has bores spaced apart at center to receive a pair of anti-friction tapered rotter bearings. Axle shafts that are adapted to have extended ends of somewhat lesser diameter, beyond splines, are journaled, spaced apart, into anti-friction tapered roller bearings of cross spider to retain and check axial and radial movement of cross spider and ring gear assembly. Thus, the assembly of cross spider and ring gear carries on full functions of a conventional differential case. Accordingly, a primary object of this invention is to propose a new improvement in an axle housing without a differential case. Another object of this invention is to propose a differential gear assembly, having eliminated a part of differential case, which substantially reduces material, labour, servicing and maintenance cost and assembling-disassembling efforts and timing. Yet another object of this invention is to propose a differential gear assembly of reduced overall dimension that provides more ground-to-rear axle housing clearance and more ground-to-transaxle housing clearance in rear-axle and front-axle drive vehicles respectively. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS: Other objects and advantages of the present invention will become apparent to those skilled in the art through the illustration of the preferred embodiments of the invention with reference to the accompanying drawings wherein the same reference numerals are used for designating similar or identical component elements throughout several views: FIG. 1 is an exploded perspective view of an axle housing of the present invention, FIG. 2 is a partially cross-sectional plan view of axle housing of the invention, FIG. 3 is a view of ring gear and cross spider in assembled relationship, taken along the lines III - III of FIG. 2, FIG. 4 is a perspective view showing a stub shaft being disposed into a groove on inner periphery of the ring gear; and, FIG.5 is a fragmentary view of a stub shaft nearly disposed in the ring gear. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS: The following specification particularly describes and ascertains the nature of this invention and the manner in which it is to be performed. This invention will be hereinafter illustrated in details with reference to the accompanying drawings of preferred embodiments throughout which like reference letters indicate corresponding parts in the various figures. According to this invention, an axle housing is presented by numeral reference 10. A ring gear 14 is in mesh with and driven by a pinion drive gear 12 that is rigidly fixed to a vehicle transmission output shaft 11 that is joumaled for rotation onto a pair of anti-friction tapered roller bearings (not shown). Inner periphery of ring gear 14 includes four substantially evenly spaced grooves 15,16,17,18 that longitudinally extend from backside and terminate before front teeth base thereof. The ring gear 14 also includes threaded bores 21, 22, 23, 24 on backside thereof facing side gear 61. A cross spider 30 includes stub shafts 31, 32, 33, 34 extending radially at equally spaced intervals from a central block portion 40. The stub shafts 31, 32, 33, 34 are typically round except at sides that form flattened surfaces 75,76 (Fig.2) facing side gears 61, 62 respectively, in order for cross spider 30 to be disposed into axial length of grooves 15,16, 17, 18 within ring gear 14 and to provide access for oil lubrication to spider gears 41, 42, 43, 44. The stub shafts 31, 32,33, 34 have flattened end portions 35, 36, 37, 38 designed to be received within grooves 15,16,17,18. The cross spider 30 also includes, at its central block portion 40, bores 39,49 spaced apart axially by a ring-like projection leftover 29 to receive anti-friction tapered roller bearings 53, 54 seated in races 51, 52 respectively. The spider gears 41, 42, 43, 44 and spherical thrust washers 45, 46, 47, 48 on top are rotatably mounted onto stub shafts 31, 32, 33, 34 of cross spider 30 respectively. Cont'd...3 The annular cover plate 50 includes four apertures 55, 56, 57, 58. The fasteners 25, 26, 27, 28 are passed through apertures 55,56,57,58 on cover plate 50 for securement to threaded bores 21, 22, 23, 24 on backside of ring gear 14 for retaining cross spider 30 into grooves 15, 16, 17, 18 such that cover plate 50 does not carry a torque load as seen in Fig. 1. The side gears 61, 62 include splined bores 69,79, which mesh with splines 77,78 on axle shafts 73, 74 respectively. The assembly of cross spider 30 and ring gear 14 is centered within side gears 61,62 to establish their own backlash. Thrust bearing washers 63, 64 provide surfaces for side gears 61, 62 against anti-friction tapered roller bearings 65,66 respectively, as seen in Fig. 2. The axle shafts 73, 74 are adapted to have their elongated proximate ends 71,72 beyond axle shaft splines 77,78 journaled onto anti-friction roller bearings 53,54 in facing relationship respectively. The elongated proximate ends 71,72 are having somewhat lesser diameter than axle shafts 73,74 and enough length to fit into cross spider anti-friction roller bearings 53,54. Axle shafts 73,74 are connected to vehicular wheels (not shown) through the ultimate ends (not shown) thereof. For installation, hypoid pinion drive gear 12 rigidly fixed to output drive shaft 11 is slid out from interior of axle housing frame (not shown) to be journaled onto anti-friction tapered roller bearings seated in races (both not shown). AH four spider gears 41,42, 43, 44 and spherical thrust washers 45, 46, 47, 48 on top are mounted onto stub shafts 31, 32, 33, 34 of cross spider 30. The assembled cross spider 30 is slid into grooves 15,16,17, 18 to be retained within ring gear 14 by cover plate 50 that is secured by fasteners 25, 26, 27, 28 having passed through apertures 55,56,57,58 to threaded bores 21,22,23, 24 on backside of ring gear 14. The bores 39,49 receive anti-friction tapered roller bearings 53,54 within races 51,52. The anti-friction tapered roller bearing 65 is disposed into race 67. The elongated end 71 of axle shaft 73 is slid through anti-friction tapered roHer bearing 65 and side gear 61 such that splined bore 69 meshes with spline 77. The anti-friction tapered roller bearing 53 of cross spider and ring gear assembly is journaled onto elongated end 71 of axle shaft 73 and held in that position while artti-friction tapered rotter bearing 66 is disposed onto race 68 to receive side gear 62 splined to axle shaft 74 therethrough. The elongated end 72 of axle shaft 74 is slid into and journaled onto artti-friction tapered roller bearing 54. In such configuration, as may now be appreciated, having cross spider, assembled with spherical thrust washers on top of spider gears, disposed directly into grooves formed within inner periphery of ring gear and retained by cover plate, ttie rotation of output drive shaft is transferred directly from hypoid pinion drive gear to hypoid ring gear, to spider gears through cross spider shaft, to side gears and to proximate ends of axle shafts, allowing axle shafts rotate relative one another so that the design of axle housing is such that it is assembled easily while eliminating the need for a conventional differential casing to support the ring gear, the pinion shaft and the spider gears thereupon. From foregoing discussion, which discloses and describes the preferred embodiments with reference to the accompanying drawings and claims, one skilled in the art will readily recognize that changes and modifications can be made to the preferred embodiments without departing from the scope of the inventive concepts as defined in the following claims. The preferred embodiments have 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 the words of description rather than of limitation. I claim:- 1. A motor vehicle differential gear assembly for transferring rotational torque input by a hypoid pinion drive gear rotatably driven by a transmission output shaft to a pair of substantially axially aligned rotary driven axle shafts that are journaled for rotation, the differential gear assembly of the type having a hypoid ring gear journaled for rotation concentrically with respect to axle shafts and meshing with hypoid pinion drive gear and differential pinion gears mounting a cross spider rotatable with the hypoid ring gear and further meshing with side gears coupled to vehicles axle shafts, said assembly comprising: a hypoid ring gear having an inner and an outer surface and having four evenly spaced threaded bores on the backside and forming four evenly spaced grooves onto the inner surface, the grooves are evenly spaced onto the inner surface of the hypoid ring gear opening laterally to receive the cross spider stub shafts, the grooves extend laterally from backside of the hypoid ring gear and terminating just before front teeth base; a cross spider extending four evenly spaced stub shafts of substantial radial length extending radially outwardly from central block portion, the stub shafts of the cross spider rotationally jouraling the four differential pinion gears in engagement with the side gears, the stub shafts of said cross spider are typically round beyond said central block portion except that either sides facing the side gears form flattened surfaces, the stub shafts, having squared ends, define a shoulder being received within each of the lateral grooves of the hypoid ring gear, the stub shafts of the cross spider mounting spherical thrust washers between the differential pinion gears and inner surface of the hypoid ring gear, the cross spider having a through bore forming a ring-like projection centrally within the central block portion, a pair of races disposed into the through bore formed on central block portion of the cross spider from either sides such that they are spaced apart axially to receive a pair of bearings; an annular cover plate of substantial strength, securing and retaining the cross spider to the threaded bores formed on backside of hypoid ring gear through four apertures with suitable fasteners; proximate ends of the axle shafts adapted to elongate beyond splines, elongated proximate ends of the axle shafts adapted to journal onto the bearings disposed within the central block portion of the cross spider, the length of the elongated proximate ends of the axle shafts is equal to the internal width of the bearings, the outer diameter of the elongated proximate ends of the axle shafts is equal to the inner diameter of the bearings. 2. The assembly of claim 1 wherein said bearings are ball or roller or tapered roller bearings. Dated this 24the day of September, 2004 TAIYEBI QURESH ABDULKADER

Documents:

902-mum-2004-cancelled pages(17-11-2005).pdf

902-mum-2004-claims(granted)-(17-11-2005).doc

902-mum-2004-claims(granted)-(17-11-2005).pdf

902-mum-2004-correspondence(17-11-2005).pdf

902-mum-2004-correspondence(ipo)-(29-6-2007).pdf

902-mum-2004-form 1(16-3-2005).pdf

902-mum-2004-form 1(17-11-2005).pdf

902-mum-2004-form 13(17-11-2005).pdf

902-mum-2004-form 2(granted)-(17-11-2005).doc

902-mum-2004-form 2(granted)-(17-11-2005).pdf

902-mum-2004-form 3(16-3-2005).pdf

902-mum-2004-form 3(17-11-2005).pdf

902-mum-2004-form 5(16-3-2005).pdf

902-mum-2004-form 5(17-11-2005).pdf