Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Coupling transmits torque via radially spaced ball
Reexamination Certificate
2000-12-05
2002-09-03
Binda, Greg (Department: 3679)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Coupling transmits torque via radially spaced ball
C464S167000, C464S906000
Reexamination Certificate
active
06443844
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to constant velocity stroking joints.
2. Related Art
Constant velocity (“CV”) joints have particular application in front wheel drive systems for automotive vehicles. Power is transmitted from the transmission to the drive wheels via shaft assemblies. The shaft assemblies include CV joints at their inboard and outboard ends. The inboard CV joint is coupled to the transmission and the outer CV joint is coupled to the drive wheels. During normal operation of a front wheel drive vehicle, the wheels move up and down, and thus provision must be made for both angular and axial movement of the shaft assembly.
In a typical front wheel drive system, the outboard CV joints are designed to accommodate large joint angularity, but no axial stroking. The inboard CV joints are designed to accommodate axial stroking and joint angularity. The present invention is concerned with the stroking type CV joints.
FIGS. 1-3
illustrate a prior art CV stroking joint which is commonly referred to the industry as a “ball spline Rzeppa joint”. The joint
11
includes a half shaft
13
splined to one end of which is an inner race
15
accommodated within an intermediate race
17
which in turn is disposed within an outer race
19
. A plurality of balls
21
are carried in ball grooves between end inner race
15
and intermediate race
17
and are captured within windows of a ball cage
23
to provide angular or pivotal movement of the inner race
15
and thus the shaft
13
relative to the intermediate and outer races
17
,
19
, respectively. Axial or plunging movement of the joint
11
is provided between the intermediate race
17
and outer race
19
.
The intermediate race
17
is formed on its outer surface with a plurality of axial ball guides
25
that correspond in number and alignment with ball guides
27
formed on the inner surface of the outer race
19
. A row of spline balls
29
is disposed in each of the aligned ball guides
25
,
27
to provide rolling support of the intermediate race
17
within the outer race
19
. Referring to
FIGS. 2-4
, it will be seen that the outer surface of the intermediate race
17
is formed with a pair of retaining ring grooves
31
adjacent it opposite axial ends, and that the spline balls
29
are captured between retaining rings
32
within the grooves
31
and thus cannot move beyond the ends of the intermediate race
17
.
It will be appreciated thus from
FIGS. 3 and 4
that the space between the retaining rings
32
is greater than the space occupied by the spline balls
29
, such that there is a certain amount of open space to accommodate free rolling movement of the spline balls as the intermediate race
17
is moved axially relative to the outer race
19
.
FIG. 3
shows the joint
11
with the intermediate race
17
moved to the forward limit (to the left in the drawings) of free rolling stroke of the intermediate race
17
within the outer race
19
. It will be seen that the spline balls
29
are confronting the rearward retaining ring (to the right in
FIG. 3
) and thus are no longer free to roll in the ball guides in response to additional forward axial movement of the intermediate race
17
to the left in FIG.
3
.
FIG. 4
shows the opposite extreme of inward free rolling stroke of the intermediate race
17
relative to the outer race
19
. It will be seen that in each case of the free rolling limit, there remains an axial gap or space
33
between end stops
35
,
37
of the outer race
19
, and corresponding end stops
39
,
41
of the intermediate race
17
which provides for additional forward and rearward axial displacement or stroking of the intermediate race
17
within the outer race
19
. In practice, the joint
11
operates in the zone of free rolling stroke until such point as the extreme free stroke limits are reached, as shown in
FIGS. 3 and 4
. If a sufficient axial stroking force is applied to the joint
11
, additional axial displacement or stroking of the intermediate race
17
occurs to close the forward or rearward gap
33
, but such requires the balls
21
to slide or skid along the ball guides
27
of the outer race
19
rather than rolling, as they are restrained against rolling by confrontation with the retaining rings of the intermediate race
17
.
It is an object of the present invention to improve upon such joints by increasing the free rolling travel or displacement of the intermediate race within the outer race.
SUMMARY OF THE INVENTION
A constant velocity stroking joint constructed according to the invention includes an outer race having a plurality of axially extending ball channels. An inner race is disposed within the outer race and an intermediate race is disposed between the inner and outer races and supports the inner race for angular pivotal movement relative to the outer race. The intermediate race is formed on its outer surface with a plurality of axially extending ball channels aligned with the ball channels of the outer race. The intermediate race has opposite axial ends and abutments positioned to confront the end stops of the outer race at extreme limits of axial stroking of the intermediate race within the outer race. Axially extending rows of spline balls are disposed between the intermediate race and the outer race in registry with the aligned ball channels to provide rolling support to the intermediate race during the axial stroking within the outer race. According the invention, the rows of spline balls are supported to extend beyond the ends of the intermediate race in such manner as to provide free rolling guidance of the spline balls during the axial stroking the intermediate race between the extreme limits of axial stroking of the intermediate race within the outer race.
The invention thus has the advantage of providing free rolling support to the intermediate race during its full travel within the outer race. Such support of the spline balls eliminates or greatly minimizes any sliding or skidding movement of the spline balls as with the prior art device described above.
Eliminating the skidding of the spine balls provides for a smoother, quieter CV joint and eliminates any shutter or vibrations which may be associated with such skidding of the balls inherent in the prior art constructions.
Providing full free rolling support of the balls during the full stroke of the intermediate race has the further advantage of prolonging the operating life of the joint by decreasing wear on the spline balls and associated ball channels attributed to skidding action of the spline balls.
REFERENCES:
patent: 1665280 (1928-04-01), Rzeppa
patent: 1690714 (1928-11-01), Braddock
patent: 3310960 (1967-03-01), Cull
patent: 4991981 (1991-02-01), Baxter
patent: 5542515 (1996-08-01), Richardson et al.
patent: 6251021 (2001-06-01), Jacob
Anderson Edmund P.
Binda Greg
Delphi Technologies Inc.
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