Machine element or mechanism – Elements – Gear casings
Reexamination Certificate
2002-03-20
2004-05-04
Kim, Chong H. (Department: 3682)
Machine element or mechanism
Elements
Gear casings
Reexamination Certificate
active
06729207
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to axle assemblies for motor vehicles in general, and more particularly to a rigid drive axle assembly including a support beam member having a substantially flat central section and two opposite axle shaft members rotatably supported in a spaced relationship with respect to the central section of the support beam member.
2. Description of the Prior Art
Rigid drive axle assemblies are well known structures that are in common use in most motor vehicles. Such axle assemblies include a number of components that are adapted to transmit rotational power from an engine of the motor vehicle to wheels thereof. Typically, the rigid drive axle assembly includes a hollow axle housing, a differential, which is rotatably supported within the axle housing by a non-rotating carrier. The differential is connected between an input drive shaft extending from the vehicle engine and a pair of output axle shafts extending to the vehicle wheels. The axle shafts are contained in respective non-rotating tubes that are secured to the carrier. Thus, rotation of the differential by the drive shaft causes corresponding rotation of the axle shafts. The carrier and the tubes form a housing for these drive train components of the axle assembly, inasmuch as the differential and the axle shafts are supported for rotation therein.
The axle housings are generally classified into two basic types. The first axle housing type is a unitized carrier construction, commonly referred to as a Salisbury or Spicer type axle assembly, illustrated in FIG.
1
. In this structure, the Salisbury type axle assembly
301
includes a carrier
312
(which houses the rotatable differential mechanism
340
) is directly connected to the two tubes
316
and
317
(which house the rotatable axle shafts
320
). An opening is provided at the rear of the carrier to permit assembly of the differential therein. A cover
326
closes this opening during the use. The cover
326
is connected by bolts
328
to a rear face
330
of the carrier
312
hydraulically seals the housing against the passage of lubricant. A brake assembly
314
located at the end of a tube
316
extending outboard from the ends of an axle carrier
312
. Located within the differential case is a drive pinion
332
rotatably supported by a rear drive pinion bearing
334
and a front drive pinion bearing (not shown) supported on the inner surface of a portion of the axle carrier casing
338
that extends forward from the center line of the axle assembly. A driveshaft, driveably connected to the output shaft of a transmission, is coupled to the shaft of the drive pinion
332
. The differential mechanism
340
, located within the differential case
348
, includes a ring gear
342
, in continuous meshing engagement with drive pinion
332
and supported rotatably on the differential rear drive pinion bearing
334
and the front drive pinion bearing located within the housing gear and cylindrical extension
338
of the carrier
312
. The axle carrier
312
also includes laterally directed tubular extensions
344
,
346
, which receive therein the ends of housing tubes
316
and
317
, respectively. Located within the carrier
312
is a differential case
348
, on which bevel pinion gears
350
,
352
are supported for rotation on a differential pinion shaft
354
. Side bevel gears
356
,
358
are in continuous meshing engagement with pinions
350
,
352
and are driveably connected to left and right axle shafts
320
, located respectively within tubes
316
and
317
. The axle shaft
320
is connected to the corresponding side bevel gear
356
. Unitized carrier axle housing constructions of this type are economical to manufacture and are readily adaptable for a variety of vehicles.
The second axle housing type is a separable carrier construction, and is commonly referred to as a Banjo type axle, illustrated in FIG.
2
. In this structure, the Banjo type axle
401
includes an axle housing
402
having axle tubes
406
a
and
406
b
connected together by a central member
404
. The axle tubes
406
a
and
406
b
are adapted to receive and rotatably support output axle shafts
414
a
and
414
b
. The axle housing
402
is formed separate and apart from a carrier
422
. This central member
404
is generally hollow and cylindrical in shape, having a large generally circular opening
410
formed therethrough. During assembly, a differential
420
is first assembled within the carrier
422
, then the carrier
422
is secured to the central member
404
of the axle housing
402
. The overall shape of this type of axle housing (i.e., the generally round shape of the central member
404
and the elongated tubes
406
a
and
406
b
extending therefrom) generally resembles the shape of a banjo musical instrument. Hence, this type of axle housing is referred to as the Banjo type axle housing. The Banjo type axle housings are advantageous because the carrier
422
and differential
420
can be removed from the axle assembly
401
for service without disturbing the other components thereof.
However, both Banjo and Salisbury type axles have their disadvantages. Thus, there is a need for a rigid drive axle assembly that combines the advantages of both Banjo and Salisbury type axles and lessens their shortcomings.
SUMMARY OF THE INVENTION
The present invention provides a novel rigid drive axle assembly for motor vehicles. The rigid drive axle assembly in accordance with the present invention comprises a support beam member having a substantially flat, enlarged central section and two opposite arm sections axially outwardly extending from the central section. The drive axle assembly further comprises a differential assembly fastened to the enlarged central section of the support beam member, and two opposite axle shaft members outwardly extending from the differential assembly, and rotatably supported by the arm sections of the support beam member so that the axle shaft members are spaced from the central section of the support beam member in a driving direction of the motor vehicle. Distal ends of the axle shaft members are provided with flange members adapted for mounting corresponding wheel hubs.
The differential assembly includes a differential carrier frame member fastened to the central section of the support beam member, and provided for rotatably supporting a differential case and a drive pinion. The differential case houses a conventional differential gear mechanism, well known to those skilled in the art. The drive pinion has a pinion gear in continuous meshing engagement with a ring gear, and a pinion shaft operatively coupled to a vehicular drive shaft driven by a vehicular powerplant through an input yoke. The differential assembly is enclosed into a housing formed by a rear cover and a front cover secured to opposite surfaces of the central section of the beam member in any appropriate manner well known in the art. The front cover has a font opening for rotatably supporting and receiving therethrough a distal end of the pinion shaft of the drive pinion. The rear cover incorporates two opposite through holes for receiving the axle shaft members therethrough. Each of the through holes is provided with a self-centering seal.
The differential carrier frame member is, preferably, a single-piece metal part manufactured by casting or forging. The differential carrier frame member has a generally Y-shaped configuration and includes a neck portion and two opposite, axially spaced, coaxial bearing hub portions attached to the neck portion through respective leg portions. The neck portion has an opening therethrough adapted for receiving and rotatably supporting the drive pinion through an appropriate anti-friction bearing, preferably a roller bearing. The bearing hub portions are provided with respective openings therethrough adapted for receiving appropriate anti-friction bearings for rotatably supporting the differential carrier. Moreover, the bearing hub portions are provided with mounting flange portio
Allmandinger Timothy Bernard
Hoefer Sean Karl
Irwin Earl James
Maser Gregory James
Nanua Parvinder Singh
Kim Chong H.
Liniak Berenato & White
Torque-Traction Technologies Inc.
LandOfFree
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