Rotary shafts – gudgeons – housings – and flexible couplings for ro – Coupling accommodates drive between members having... – Tripod coupling
Reexamination Certificate
2001-10-15
2003-03-18
Browne, Lynne H. (Department: 3679)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Coupling accommodates drive between members having...
Tripod coupling
C464S124000, C464S905000
Reexamination Certificate
active
06533668
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a tripod type constant velocity joint, which is disposed between rotating shafts connected at a joint angle with each other in a drive axle of, for example, an automobile, for transmitting a rotational torque.
BACKGROUND OF THE INVENTION
Tripod type constant velocity joints are one of a number of types of constant velocity joints used in drive axles of, for example, automobiles.
For example, Japanese Laid Open Patent Application Nos. S63(1988)186036 and S62(1987)-233522 disclose a tripod type constant velocity joint
1
, as shown in FIGS.
18
and
19
(A—A cross sectional view of FIG.
18
). This constant velocity joint
10
is provided with a hollow cylindrical housing
13
which is secured to an end of a first rotating shaft
12
serving as a drive shaft or the like on the differential gear side, and a tripod
15
which is secured to an end of a second rotating shaft
14
serving as driven shaft or the like on the wheel side. Grooves
16
are formed at three locations on the internal face of the housing
13
at an even spacing in the circumferential direction and extend outwardly in the radial direction of the housing
13
from said internal face.
On the other hand, the tripod
15
secured at one end of the second rotating shaft
14
comprises a unified form of a boss
17
for supporting the tripod
15
at one end of the second rotating shaft
14
, and cylindrical trunnions
18
extending radially from three locations at equal spacing around the boss
17
in the circumferential direction. Around the tip end of the respective trunnions
18
, rollers
19
are rotatably supported through a needle bearing
10
, while allowing the rollers to be displaced in the axial direction by certain distances. A tripod type constant velocity joint
10
is provided by engaging the respective rollers
19
with the respective guide grooves
16
on an inner face of the housing
13
. The respective pairs of side faces
11
, on which each of the above guide grooves
16
is provided, are formed to circular recesses. Accordingly, each of the rollers
9
is rotatably and pivotably supported between the respective pairs of the side faces
11
.
When the constant velocity joint
10
as described above is used, for example, the first rotational shaft
12
is rotated. The rotational force of the first rotational shaft
12
is, from the housing
13
, through the roller
19
, the needle bearing
20
and the trunnion
18
, transmitted to the boss
17
of the tripod
15
, thereby rotating the second rotational shaft
14
. Further, if a central axis of the first rotational shaft
12
is not aligned with that of the second rotational shaft
14
(namely, a joint angle is not zero in the constant velocity joint
10
), each of the trunnion
18
displaces relative to the side face
16
a
of each of the guide groove
16
to move around the tripod
15
, as shown in
FIGS. 18 and 19
. At this time, the rollers
19
supported at the ends of the trunnions
18
move along the axial directions of the trunnions
18
, respectively, while rolling on the side faces
16
a
of the guide grooves
16
, respectively. Such movements ensure that a constant velocity between the first and second rotational shafts
12
and
14
is achieved.
If the first and second rotational shafts
12
and
14
are rotated with the joint angle present, in the case of the constant velocity joint
10
which is constructed and operated as described above, each of the rollers
19
moves with complexity. For example, each of the rollers
19
moves in the rotational axis
12
of the housing
13
along each of the side faces
16
a
of the respective guide grooves
16
, while the orientations of the rollers
19
are being changed and further the rollers
19
displace in the axial direction of the trunnion
18
. Such complex movements of the rollers
19
cannot cause a relative movement between a peripheral outside face of each of the rollers
19
and each of the side faces
16
a
of the guide grooves
16
to be smoothly effected. Thus, a relatively large friction occurs between the faces. As a result, in the constant velocity joint
10
, three-directional axial forces occurs per one rotation. It is known that an adverse oscillation referred to as “shudder” may occur in some cases, if a large torque is transmitted with a relatively large joint angle present.
In order to solve the above problem, FR275280 discloses a structure as shown in FIG.
20
and the Japanese Laid-Open patent application No. H3-172619 discloses a structure as shown in FIG.
21
. In the structure shown in
FIG. 20
, a roller is guided parallel to a housing groove and a spherical trunnion
18
can swing and pivot around a inner spherical surface of an inner roller
19
b
. Further, a contact area between the inner spherical surface of the inner roller
19
b
and the trunnion
18
when receiving a torque for a load is shaped to an ellipse having a larger long diameter, because a radius “r” of a longitudinal cross-sectional shape of the spherical trunnion
18
is smaller than a radius “r
3
” of the trunnion
18
. In the structure shown in
FIG. 21
, a torque for a load is received between an inner cylindrical surface of an inner roller
19
b
and a spherical trunnion
18
. Thus, a width (a short diameter) “b” of a contact ellipse shaped therebetween is smaller and a contact length “a”, in the circumference of a contact area, which corresponds to a long diameter of the contact ellipse is larger. In fact, the contact ellipse is positioned on the side of the trunnion
18
facing with the side face
16
a
of the guide groove
16
, although the contact ellipse is shown at the front side for clarification in FIG.
21
. When these joints rotate with joint angles present upon receiving loads, as shown in
FIG. 22
, a pivotal movement (of a direction indicated by an arrow “H”) of the trunnion
18
causes a pivotal sliding action to be occurred on the contact ellipse. Then the pivotal sliding action operates as a spin moment (of a rotational direction indicated by arrows “B”) so as to change a rolling direction of the roller assembly
19
comprising the inner roller
19
b
and the outer roller
19
a
, which are assembled together via a needle bearing
21
. As a result, the direction of the roller assembly
19
is changed until it is in contact with inner or outer face of the guide groove
16
, and in addition a contact force is increased. Moreover, the roller assembly
19
displaces not to be parallel to the guide groove
16
. Hence, it is difficult for the roller assembly
19
to be smoothly rolled, bringing about a significant rolling resistance.
It is contemplated to enlarge a difference between an inner diameter of the inner roller
19
b
and an outer diameter of the trunnion
18
, in order to reduce the long diameter “a” of the contact ellipse. In this case, however, there is raised a new problem in which the joint fluctuates when moving along the rotational direction.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the above disadvantages of prior art, that is, to provide a tripod type constant velocity joint having a simple structure which is both highly strong and durable, which can diminish a spin moment acting on the contact ellipse formed between the outer face of the trunnion and the inner face of the inner roller, due to the pivotal sliding movement of the trunnion axis, and which can minimize a rolling resistance when rotating with any joint angle present.
To solve the above problems, according to the invention, a constant velocity joint of tripod type comprises:
A cylindrical hollow housing defining an opening at one end, and being secured at its opposite end to a first rotating shaft such that a central axis of the housing is aligned with that of the first rotating shaft, an inner face of the housing being provided with three guide grooves extending in a axial direction of the housing and being spaced apart equally in a circumferential direction, each groove having a pair of side faces opposed to each oth
Ikeda Toshihiro
Ishijima Minoru
Mizukoshi Yasumasa
Anderson Edmund P.
Browne Lynne H.
Delphi Technologies Inc.
Thompson Kenn
LandOfFree
Constant velocity joint of tripod type does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Constant velocity joint of tripod type, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constant velocity joint of tripod type will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3012760