Bevel gear and pinion drive with biased thrust bearing

A spiral bevel pinion and its meshing bevel gear are carried in a typical housing. The problem solved is accommodation of the axial thrust imparted to the pinion shaft during functioning of the drive train, the solution being in the form of biasing means backing up the thrust bearing ahead of the pinion and enabling the use of lighter-weight, less expensive bearings. A further feature is the use of a further bearing in the form of a needle bearing having radial needles between the inner race ring of the main thrust bearing and the biasing means.

BACKGROUND OF THE INVENTION 
It is characteristic of bevel pinion and bevel gear drives that axial 
thrust forces are imparted to the pinion shaft during driving of the 
vehicle in which the drive train is incorporated. Thus, in a typical 
installation, such as in a farm or industrial vehicle, the pinion shaft 
extends for-and-aft and the pinion is fixed to the rear end of this shaft 
and meshes with a bevel gear journaled in the housing on a transverse 
horizontal axis. If the final drive is for the rear drive axles of the 
vehicle, the axial thrust forces on the pinion shaft will be forwardly. 
The prior solution to compensating for or accommodating the forward thrust 
has involved the use of heavier, stronger and thus more expensive design 
and materials, it being customary to utilize a so-called combination 
radial-thrust bearing, usually of the tapered roller bearing type. 
According to the present invention, resort is had to lower-cost design 
because of the use of biasing means interposed between an annular shoulder 
in the housing and the inner race ring of the bearing. Preferably this 
means is of the coned-washer type, often referred to as a "Belleville" 
spring. This spring resists in a yielding fashion the forward thrust load 
on the main bearing. A low-friction bearing is interposed between the 
spring and the inner race ring and this bearing is preferably of the 
needle type, having its needles disposed radially.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
For the purposes of simplicity and clarity, the elements of the 
construction will be referred to as being oriented geographically to the 
extent that the left-hand edge of the sheet is toward the front of the 
vehicle. Like expressions will appear in the claims, but it is to be 
understood that the invention is equally applicable to otherwise-arranged 
components. 
A basic housing is shown at 10 having a transverse wall 12 provided with a 
circular opening 14 within which is received the rear end of a supporting 
quill 16. This is typically fixed to the housing wall by a circle of cap 
screws, one of which appears at 18. A pinion shaft 20 extends coaxially 
fore-and-aft through the quill and has a spiral bevel pinion 22 fixed to 
its rear end, which pinion meshes conventionally with a level gear 24. The 
pinion shaft is journaled in the quill by fore-and-aft spaced apart 
bearings 26 and 28, which to that extent is conventional, as is the 
journaling of the bevel gear. It is deemed that the latter is well enough 
known to forego detailed description. 
The bearing 28 may be a conventional radial-thrust bearing of the tapered 
roller bearing type and has an inner race ring 30, an outer race ring 32 
and a plurality of tapered rolling elements 34 between them. The junction 
of the pinion shaft and its pinion establishes a shoulder 36 which abuts 
forwardly against the inner race ring. The quill 16, in the area of the 
bearing 28, is formed as a collar 38 which has an interior radial shoulder 
40 for receiving the front of the outer race ring. In a preferred 
construction, a shim pack 42 is interposed between the race ring and the 
shoulder. The thickness of this pack is determined at the time of 
installation. The collar portion has an interior annulus 44 provided with 
a second radical shoulder 46. In the present design, the shoulder 46 is 
spaced ahead of the inner race ring 30 and in this annular space is 
located the improved biasing means generally denoted 48. According to the 
preferred embodiment here, the biasing means comprises a spring 50 and a 
low-friction bearing means 52. The spring selected is of the coned-washer 
type, often referred to as a "Belleville" spring, and the bearing 52 is of 
the needle type having its needles disposed radially and typically rolling 
between two radical rings 54. The rear ring abuts the front of the inner 
race ring 30 and the front ring abuts or is abutted by the annular spring 
50, the spring being biased between this front ring and the rear face of 
the annular shoulder 46, thus exerting a rearward force against the 
bearing 28 in opposition to the forward thrust force resulting from 
driving mesh of the level pinion and gear. As previously stated, this 
design enables the use of a much less costly radial thrust bearing, the 
savings more than paying for the spring 50 and the needle bearing 52. 
Many modifications in the preferred embodiment will occur to those versed 
in the art, all without departure from the spirit and scope of the 
invention.