U.S. patent application number 14/878611 was filed with the patent office on 2019-01-10 for tripot constant velocity joint.
The applicant listed for this patent is STEERING SOLUTIONS IP HOLDING CORPORATION. Invention is credited to Jeffrey P. Courville, Jon N. Miller, Eduardo R. Mondragon-Parra, William P. Skvarla, Steven M. Thomas.
Application Number | 20190010991 14/878611 |
Document ID | / |
Family ID | 55852199 |
Filed Date | 2019-01-10 |
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United States Patent
Application |
20190010991 |
Kind Code |
A9 |
Thomas; Steven M. ; et
al. |
January 10, 2019 |
TRIPOT CONSTANT VELOCITY JOINT
Abstract
A tripot constant velocity joint includes a housing defining a
guide channel. A spider member is received within the housing and
includes a trunnion having a functional outer surface with a convex
profile defined by a first principal radius of curvature and a
second principal radius of curvature different from the first
principal radius of curvature. A first inner surface of a first
ball member engages the functional outer surface of the trunnion. A
first outer surface of the first ball member is provided with a
non-symmetric piecewise continuous profile that engages the first
sidewall.
Inventors: |
Thomas; Steven M.; (Saginaw,
MI) ; Skvarla; William P.; (Saginaw, MI) ;
Mondragon-Parra; Eduardo R.; (Freeland, MI) ;
Courville; Jeffrey P.; (Frankenmuth, MI) ; Miller;
Jon N.; (Merrill, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
STEERING SOLUTIONS IP HOLDING CORPORATION |
SAGINAW |
MI |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20160123403 A1 |
May 5, 2016 |
|
|
Family ID: |
55852199 |
Appl. No.: |
14/878611 |
Filed: |
October 8, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62072757 |
Oct 30, 2014 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16D 3/2055 20130101;
Y10S 464/905 20130101 |
International
Class: |
F16D 3/205 20060101
F16D003/205 |
Claims
1. A tripot constant velocity joint, comprising: a housing
connected to a first shaft extending along a first axis, the
housing having a guide channel that includes a first sidewall, a
second sidewall disposed opposite the first sidewall, and a top
wall extending between the first sidewall and the second sidewall;
a spider member, received within the housing and connected to a
second shaft extending along a second axis, the spider member
including a trunnion having a functional outer surface with a
convex profile characterized by a first principal radius of
curvature and a second principal radius of curvature orthogonal to
the first principal radius of curvature, the first principal radius
of curvature is different from the second principal radius of
curvature; and a ball set disposed on the functional outer surface
of the trunnion including: a first ball member having a first inner
surface and a first outer surface disposed opposite the first inner
surface, the first inner surface having a piecewise concave
continuous profile that engages the functional outer surface of the
trunnion, a second ball member having a second inner surface and a
second outer surface disposed opposite the second inner surface and
defined by a non-symmetric piecewise continuous profile, the
non-symmetric piecewise continuous profile defined by a
substantially straight portion and a convex portion adjacent to the
substantially straight portion, the second outer surface engages
the first sidewall, and a plurality of rolling elements disposed
between the first outer surface and the second inner surface.
2. The tripot constant velocity joint of claim 1, wherein a ratio
between the first principal radius of curvature and the second
principal radius of curvature is less than one.
3. The tripot constant velocity joint of claim 1, wherein a ratio
between the first principal radius of curvature and the second
principal radius of curvature is greater than one.
4. The tripot constant velocity joint of claim 1, wherein the first
principal radius of curvature progressively decreases along a first
line segment in a direction that extends away from an equatorial
plane towards a trunnion end surface is at least partially
disposed.
5. The tripot constant velocity joint of claim 1, wherein the
second principal radius of curvature progressively decreases along
a second line segment in a direction that extends away from a
transverse plane.
6. The tripot constant velocity joint of claim 1, wherein the
substantially straight portion tapers towards an axis of the ball
set.
7. The tripot constant velocity joint of claim 1, wherein the first
outer surface engages the second inner surface.
8. The tripot constant velocity joint of claim 1, wherein the first
sidewall has a generally concave profile defined by a first
sidewall portion having a first sidewall portion radius of
curvature, a second sidewall portion having a second sidewall
portion radius of curvature, and a third sidewall portion having a
third sidewall portion radius of curvature.
9. The tripot constant velocity joint of claim 8, wherein the
second sidewall portion and the third sidewall portion engage the
second outer surface and the first sidewall portion does not engage
the second outer surface.
10. The tripot constant velocity joint of claim 8, wherein the
second sidewall portion radius of curvature is greater than the
first sidewall portion radius of curvature and the third sidewall
portion radius of curvature.
11. The tripot constant velocity joint of claim 8, wherein the
second outer surface having an undercut proximate a transition
region between the second sidewall portion and the third sidewall
portion such that the second outer surface does not engage the
first sidewall proximate the transition region.
12. The tripot constant velocity joint of claim 1, wherein the top
wall includes one or more protrusions extending towards the second
axis and disposed substantially parallel to the second axis.
13. The tripot constant velocity joint of claim 12, wherein in
response to an over articulation condition in which the first ball
member detaches from the trunnion, engages the protrusion, and a
return from an over articulation condition of the tripot constant
velocity joint to an articulation condition within an articulation
threshold the first ball member reattaches to the trunnion.
14. The tripot constant velocity joint of claim 1, wherein an
overall coefficient of friction of the tripot constant velocity
joint as a result of a lubricant is less than 0.1.
15. A tripot constant velocity joint, comprising: a housing
defining a guide channel that includes: a first sidewall provided
with a concave profile defined by a first sidewall portion having a
first sidewall portion radius of curvature and a second sidewall
portion having a second sidewall portion radius of curvature, the
second sidewall portion radius of curvature greater than the first
sidewall portion radius of curvature, a second sidewall disposed
opposite the first sidewall, and a top wall extending between the
first sidewall and the second sidewall; a spider member, received
within the housing and connected to a second shaft extending along
a second axis, the spider member including a trunnion having a
functional outer surface with a convex profile defined by a first
principal radius of curvature and a second principal radius of
curvature orthogonal to the first principal radius of curvature,
the first principal radius of curvature is different from the
second principal radius of curvature; and a ball set disposed on
the functional outer surface of the trunnion including: a first
ball member having a first inner surface and a first outer surface
disposed opposite the first inner surface, the first inner surface
having a piecewise concave continuous profile that engages the
functional outer surface of the trunnion, and a second ball member
having a second inner surface and a second outer surface disposed
opposite the second inner surface and defined by a non-symmetric
piecewise continuous profile, the non-symmetric piecewise
continuous profile defined by a substantially straight portion and
a convex portion adjacent to the substantially straight portion,
the second outer surface engages the first sidewall.
16. A tripot constant velocity joint, comprising: a housing
including a first sidewall, a second sidewall disposed opposite the
first sidewall, and a top wall extending between the first sidewall
and the second sidewall defining a guide channel; a spider member,
received within the housing and connected to a second shaft
extending along a second axis, the spider member including a
trunnion having a functional outer surface with a convex profile
defined by a first principal radius of curvature and a second
principal radius of curvature angularly disposed to the first
principal radius of curvature, the first principal radius of
curvature is different from the second principal radius of
curvature; and a first ball member having a first inner surface and
a first outer surface disposed opposite the first inner surface,
the first inner surface engages the functional outer surface of the
trunnion and is provided with a symmetric piecewise continuous
substantially cylindrical profile, the first outer surface provided
with a non-symmetric piecewise continuous profile that engages the
first sidewall, the non-symmetric piecewise continuous profile
having a substantially straight portion and a convex portion.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application Ser. No. 61/897,759 filed Oct. 30, 2013 and U.S.
provisional application Ser. No. 62/072,747 filed Oct. 30, 2014,
the disclosures of which is hereby incorporated in their entirety
by reference herein.
BACKGROUND OF THE INVENTION
[0002] The present disclosure relates to a tripot constant velocity
joint.
[0003] Constant velocity joints are widely used for the
transmission of rotational energy. Constant velocity joints allow a
drive shaft to transmit power through a variable angle, at constant
rotational speed. One type of telescoping constant velocity is
referred to as a tripot joint. Tripot joints are particularly
useful for automotive axial drive shafts, particularly in
front-wheel-drive vehicles between the transaxle differential and
the driving wheel, as well as other applications. These telescoping
constant velocity joint transmit a torque at various rotational
speeds, joint angles and telescopic positions between shaft
members.
SUMMARY OF THE INVENTION
[0004] A tripot constant velocity joint includes a housing, a
spider member, and a ball set. The housing is connected to a first
shaft extending along a first axis. The housing has a guide channel
that includes a first sidewall, a second sidewall disposed opposite
the first sidewall, and a top wall extending between the first
sidewall and the second sidewall. The spider member is received
within the housing and connected to a second shaft extending along
a second axis. The spider member includes a trunnion having a
functional outer surface with a convex profile characterized by a
first principal radius of curvature and a second principal radius
of curvature orthogonal to the first principal radius of curvature.
The first principal radius of curvature is different from the
second principal radius of curvature. The ball set disposed on the
functional outer surface of the trunnion includes a first ball
member, a second ball member, and a plurality of rolling elements.
The first ball member having a first inner surface and a first
outer surface disposed opposite the first inner surface. The first
inner surface having a piecewise concave continuous profile that
engages the functional outer surface of the trunnion. The second
ball member having a second inner surface and a second outer
surface disposed opposite the second inner surface and defined by a
non-symmetric piecewise continuous profile. The non-symmetric
piecewise continuous profile defined by a substantially straight
portion and a convex portion adjacent to the substantially straight
portion. The second outer surface engages the first sidewall. The
plurality of rolling elements disposed between the first outer
surface and the second inner surface . . . .
[0005] A tripot constant velocity joint including a housing, a
spider member, and a ball set. The housing defining a guide channel
that includes a first sidewall, a second sidewall, and a top wall.
The first sidewall is provided with a concave profile defined by a
first sidewall portion having a first sidewall portion radius of
curvature and a second sidewall portion having a second sidewall
portion radius of curvature. The second sidewall portion radius of
curvature being greater than the first sidewall portion radius of
curvature. The second sidewall disposed opposite the first
sidewall. The top wall extending between the first sidewall and the
second sidewall. The spider member is received within the housing
and connected to a second shaft extending along a second axis. The
spider member includes a trunnion having a functional outer surface
with a convex profile defined by a first principal radius of
curvature and a second principal radius of curvature orthogonal to
the first principal radius of curvature. The first principal radius
of curvature is different from the second principal radius of
curvature. The ball set disposed on the functional outer surface of
the trunnion. The ball set includes a first ball member and a
second ball member. The first ball member has a first inner surface
and a first outer surface disposed opposite the first inner
surface. The first inner surface having a piecewise concave
continuous profile that engages the functional outer surface of the
trunnion. The second ball member having a second inner surface and
a second outer surface disposed opposite the second inner surface
and defined by a non-symmetric piecewise continuous profile. The
non-symmetric piecewise continuous profile defined by a
substantially straight portion and a convex portion adjacent to the
substantially straight portion. The second outer surface engages
the first sidewall.
[0006] A tripot constant velocity joint includes a housing, a
spider member, and a first ball member. The housing includes a
first sidewall, a second sidewall disposed opposite the first
sidewall, and a top wall extending between the first sidewall and
the second sidewall defining a guide channel. The spider member is
received within the housing and is connected to a second shaft
extending along a second axis. The spider member including a
trunnion having a functional outer surface with a convex profile
defined by a first principal radius of curvature and a second
principal radius of curvature orthogonal to the first principal
radius of curvature. The first principal radius of curvature is
different from the second principal radius of curvature. The first
ball member has a first inner surface and a first outer surface
disposed opposite the first inner surface. The first inner surface
engages the functional outer surface of the trunnion and is
provided with a symmetric piecewise continuous substantially
cylindrical profile. The first outer surface provided with a
non-symmetric piecewise continuous profile that engages the first
sidewall. The non-symmetric piecewise continuous profile having a
substantially straight portion and a convex portion.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The subject matter which is regarded as the invention is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features, and advantages of the invention are apparent from the
following detailed description taken in conjunction with the
accompanying drawings in which:
[0008] FIG. 1 is a partial perspective view of a tripot constant
velocity joint;
[0009] FIG. 2 is a partial perspective view of the tripot constant
velocity joint illustrating the joint within a predetermined range
of angular articulation;
[0010] FIG. 3 is an isometric view of the spider; and
[0011] FIG. 4 is a partial section view of the functional outer
surface of the trunnion
[0012] FIG. 5A is a cross-sectional view along section 3-3 of FIG.
1 of a first embodiment of the tripot constant velocity joint;
[0013] FIG. 5B is a cross-sectional view along section 3-3 of FIG.
1 of a second embodiment of the tripot constant velocity joint;
and
[0014] FIG. 5C is a cross-sectional view along section 3-3 of FIG.
1 of a third embodiment of the tripot constant velocity joint.
DETAILED DESCRIPTION
[0015] Referring now to the Figures, where the invention will be
described with reference to specific embodiments, without limiting
same, it is to be understood that the disclosed embodiments are
merely exemplary of the invention that is embodied in various and
alternative forms. The figures are not necessarily to scale; some
features are exaggerated or minimized to show details of particular
components. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely
as a representative basis for teaching one skilled in the art to
variously employ the present invention.
[0016] Referring to the FIGS. 1 and 2, a constant velocity joint 10
is shown. The constant velocity joint is a telescoping constant
velocity joint such as a tripod or tripot constant velocity joint.
The constant velocity joint 10 is provided with a vehicle such as a
truck, automobile, recreational vehicle, or cargo vehicle, or the
like. Such a constant velocity joint 10 may be suitable for use in
front wheel drive vehicles and is disposed between and operatively
coupled to a transaxle and a driving wheel or other applications
where torque is transfer between two rotatable shaft members with
possible axial position or angular position changes relative to
each other. The tripot constant velocity joint transmits torque
between a first shaft member 12 and a second shaft member 14. The
tripot constant velocity joint is configured to transmit torque
from the first shaft member 12 to the second shaft member 14
through various rotational speeds, joint angles, or telescopic
positions.
[0017] The first shaft member 12 extends along a first axis 20. The
second shaft member 14 extends along a second axis 22. The first
shaft member 12 and the second shaft member 14 are configured to
articulate and/or telescope relative to each other about their
respective axes. The first axis 20 and the second axis 22 coincide
or are collinear when the constant velocity joint 10 is at a joint
angle of 0 degrees. As shown in FIG. 2, the first axis 20 and the
second axis 22 intersect when the constant velocity joint 10 is
articulated or bent at an angle, i.e. when the first shaft member
12 and the second shaft member 14 are articulated relative to each
other. The constant velocity joint 10 includes a housing 30, a
spider 32, and a ball set 34.
[0018] The housing 30 is connected to the first shaft member 12 and
extends along the first axis 20. The combination of the housing 30
and the first shaft member 12 are rotatable about the first axis
20. The housing 30 defines a plurality of ball set tracks or guide
channels 40. Each guide channel 40 extends axially along and is
disposed substantially parallel to the first axis 20. As shown in
the Figures, the housing 30 defines three guide channels that are
radially spaced apart about the first axis 20. Each guide channel
40 is equally spaced apart at 120.degree. intervals from each
other. Each guide channel 40 includes a first sidewall 42, a second
sidewall 44, and a top wall 46.
[0019] The first sidewall 42 and the second sidewall 44 extend away
from the first axis 20 towards the top wall 46. The second sidewall
44 is disposed opposite the first sidewall 42. The first sidewall
42 is disposed substantially parallel to but is not coplanar with
the second sidewall 44. The top wall 46 extends between the first
sidewall 42 and the second sidewall 44. The top wall 46 is disposed
substantially perpendicular to both of the first sidewall 42 and
the second sidewall 44. The top wall 46 is disposed substantially
parallel to the first axis 20. The top wall 46 is disposed further
from the first axis 20 than the first sidewall 42 and the second
sidewall 44.
[0020] The first sidewall 42 and the second sidewall 44 each have a
generally concave profile when viewed in a cross-section transverse
to the first axis 20. The generally concave profile will be
described with reference to the first sidewall 42 however the
second sidewall 44 may also have a similar but mirrored or
diametrically opposed configuration. The first sidewall 42 is a
piecewise continuous surface that defines the generally piecewise
concave continuous profile. The generally piecewise concave
continuous profile of the first sidewall 42 is defined by a first
sidewall portion 50, a second sidewall portion 52, and a third
sidewall portion 54.
[0021] The first sidewall portion 50 is disposed adjacent to and
between the top wall 46 and the second sidewall portion 52. The
first sidewall portion 50 has a first sidewall portion radius of
curvature, rs1. A transition region 56 extends between the first
sidewall portion 50 and the second sidewall portion 52. The
transition region 56 provides a substantially smooth or continuous
transition between the first sidewall portion 50 and the second
sidewall portion 52. The second sidewall portion 52 is disposed
between the first sidewall portion 50 and the third sidewall
portion 54. The second sidewall portion 52 has a second sidewall
portion radius of curvature, rs2. The third sidewall portion 54 is
disposed adjacent to the second sidewall portion 52. The third
sidewall portion 54 has a third sidewall portion radius of
curvature, rs3.
[0022] The second sidewall portion radius of curvature, rs2 has
infinite large radius of curvature, larger than the first sidewall
portion radius of curvature, rs1, such that the second sidewall
portion 52 is a substantially straight portion. The substantially
straight portion tapers towards the trunnion axis 76 or an axis of
the ball set 34 such that the second sidewall portion 52 is
inclined or declined with respect to the trunnion axis 76 or an
axis of the ball set 34.
[0023] The first sidewall portion radius of curvature, rs1, and the
third sidewall portion radius of curvature, rs3, defines the
generally concave profile of the first sidewall 42. An absolute
value of a ratio between the third sidewall portion radius of
curvature, rs3, and the first sidewall portion radius of curvature,
rs1, may be greater or less than one.
[0024] The top wall 46 includes a protrusion 60 extending along a
face of the top wall 46. The protrusion 60 extends substantially
parallel to the first axis 20 and extends towards the first axis
20. In at least one embodiment, the protrusion 60 extends towards
the second axis 22. The protrusion 60 defines a center guide
disposed substantially equidistant from the first sidewall 42 and
the second sidewall 44. The protrusion 60 is disposed closer to a
portion of the spider 32 than the top wall 46.
[0025] The spider 32 is connected to the second shaft member 14 via
a splined bore for an engagement with splines on the second shaft
member 14. The spider 32 is received within the housing 30. The
spider 32 and the second shaft member 14 is configured to move
relative to the housing 30 and the first shaft member 12. The
spider 32 and the second shaft member 14 are configured to
articulate relative to the housing 30 and the first shaft member 12
such that the second axis 22 is disposed at an angle with respect
to the first axis 20. The spider 32 includes a plurality of spider
members 70 extending away from the splined bore, configured as
protrusions. As shown in the Figures, the spider 32 defines three
spider members that are radially spaced apart about the second axis
22. Each spider member is equally spaced apart at 120.degree.
intervals from each other and corresponds to a guide channel. Each
spider member of the plurality of spider members 70 is configured
as a trunnion 72 having a trunnion end surface 74 disposed
proximate the protrusion 60.
[0026] The trunnion 72 extends along a trunnion axis 76 away from
the second axis 22. The trunnion axis 76 is disposed substantially
perpendicular to the second axis 22. The trunnion 72 has a
functional outer surface 80 that transmits torque or force that is
adjacent to a non-functional outer surface 81 of the trunnion 72
that does not transmit torque or force. The functional outer
surface 80 has a non-cylindrical profile. The functional outer
surface 80 has a convex profile that is concentric with the
trunnion axis 76, such that it is a convex outer surface. The
convex profile is a truncated toroid or interrupted toroid and is
described by a radial arc or radius of curvature that is rotated
about a centroid.
[0027] The convex profile is characterized by a first principal
radius of curvature, rt1, and a second principal radius of
curvature, rt2. The first principal radius of curvature, rt1,
corresponds to a first line segment 82. The second principal radius
of curvature, rt2, corresponds to a second line segment 84. The
first line segment disposed transverse to the second line segment
84. The second principal radius of curvature, rt2, extends from the
second line segment 84 that is disposed within an equatorial plane
86. functional outer surface 80
[0028] Referring to FIGS. 3-5C, the first principal radius of
curvature, rt1, of the functional outer surface 80 is disposed on
the first line segment 82 that is formed by the intersection of the
functional outer surface 80 and a transverse plane 85 disposed
parallel to the trunnion axis 76. The second principal radius of
curvature, rt2, of the functional outer surface 80 is disposed on
the second line segment 84 formed by the intersection of the
functional outer surface 80 and an equatorial plane 86 disposed
perpendicular to trunnion axis 76. The first line segment 82 and
the second line segment 84 intersect at a single common point,
[0029] The second principal radius of curvature, rt2, is disposed
orthogonal to or perpendicular to the first principal radius of
curvature, rt1. The first principal radius of curvature, rt1, is
always less than the second principal radius of curvature, rt2. The
first principal radius of curvature, rt1, is varying along the
first line segment 82 at a rate of change similar but not limited
to a parabolic, elliptic, polynomial or hyperbolic shape. The first
principal radius of curvature, rt1, decreases in a direction that
extends away from the equatorial plane 86. The decreasing of the
first principal radius of curvature, rt1, in a direction that
extends away from the equatorial plane 86 such that the functional
outer surface 80 falls or angles towards the trunnion axis 76.
[0030] In at least one embodiment, the second principal radius of
curvature, rt2, varies along the second line segment 84 at a rate
of change similar but not limited to a parabolic, elliptic,
polynomial or hyperbolic shape.
[0031] An absolute value of a ratio between the first principal
radius of curvature, rt1, and the second principal radius of
curvature, rt2, is less than one. In at least one embodiment, the
first principal radius of curvature, rt1, is greater than the
second principal radius of curvature, rt2, corresponding to an
ellipsoid shape. An absolute value of a ratio between the first
principal radius of curvature, rt1, and the second principal radius
of curvature, rt2, is greater than one. The ratio between the first
principal radius of curvature, rt1, and the second principal radius
of curvature, rt2, not been equal to one may ensure that the
functional outer surface 80 does not have a spherical profile.
[0032] Referring to FIGS. 3 and 4, the functional outer surface 80
of the trunnion 72 will be more specifically described. The
functional outer surface 80 is a trunnion contact surface that
contacts a member of the ball set 34, with at least one contact
point. The functional outer surface 80 has a convex profile that
provides a toroid-like non-spherical surface. The first principal
radius of curvature, rt1, is disposed on the first line segment 82
that is angularly disposed with respect to the second line segment
84. In the embodiment shown the first line segment 82 is disposed
transverse to or orthogonal to the second line segment 84. The
first line segment 82 is disposed within the transverse plane 85.
The second principal radius of curvature, rt2, is disposed on the
second line segment 84 that is disposed within the equatorial plane
86. The first line segment 82 is swept or revolved about an axis
transverse or orthogonal to the trunnion axis 76. The second line
segment 84 may be an axis or equator of the toroid like
non-spherical surface that is swept or revolved about the trunnion
axis 76.
[0033] The functional outer surface 80 is characterized by the
first principal radius of curvature, rt1, and the second principal
radius of curvature, rt2. The first principal radius of curvature,
rt1, is continuously varying such that the first principal radius
of curvature, rt1, decreases in a direction that extends away from
the equatorial plane 86. The first principal radius of curvature,
rt1, progressively decreases in a direction that extends away from
the equatorial plane 86 towards the trunnion end surface 74. The
first principal radius of curvature, rt1, progressively decreases
in a direction that extends away from the equatorial plane 86 and
away from the trunnion end surface 74. The decreasing first
principal radius of curvature, rt1, in a direction that extends
away from the equatorial plane 86 results in the functional outer
surface 80 falling or angling towards the trunnion axis 76. A
linear distance between a point on the functional outer surface 80
and the trunnion axis 76 decreases in a direction that extends away
from the equatorial plane 86. In other words, a linear distance
between a point on the functional outer surface 80 and a point of
an adjoining component, such as a member of the ball set 34,
progressively increases in a direction that extends away from the
equatorial plane 86.
[0034] Referring to FIGS. 5A-5B, the ball set 34 is disposed on the
functional outer surface 80 of the trunnion 72. The trunnion 72
rotatably support the ball set 34. As shown in the Figures, three
ball assemblies are provided and disposed on respective trunnions.
The ball set 34 is disposed on a trunnion 72 and is slidably or
rollingly received within their respective guide channel 40. The
ball set 34 includes a first ball member 90, a second ball member
92, and a plurality of rolling elements 94.
[0035] The first ball member 90 has a first inner surface 100 and a
first outer surface 102. The first inner surface 100 is a piecewise
continuous surface having a concave profile that engages the
functional outer surface 80 of the trunnion 72 having a convex
profile. The first inner surface 100 has a surface texture that
meets an Rsk value of less than zero. The concave profile of the
first inner surface 100 is defined by a first ball member first
portion 110 and a first ball member second portion 112. The concave
profile of the first inner surface 100 may include a truncated
toroid, truncated ellipsoid, truncated spheroid, a piecewise
continuous profile revolved around the trunnion axis 76 or a
combination thereof.
[0036] The first ball member first portion 110 is disposed adjacent
to the first ball member second portion 112. The first ball member
first portion 110 engages the functional outer surface 80 of the
trunnion defining a first ball-trunnion contact patch 114. The
first ball member first portion 110 has a first principal radius of
curvature, rf1. The first ball member second portion 112 also
engages the functional outer surface 80 of the trunnion defining a
second ball-trunnion contact patch 116. The first ball member
second portion 112 has a second principal radius of curvature, rf2.
The second principal radius of curvature, rf2, is different from
the first principal radius of curvature, rf1. A ratio of the first
principal radius of curvature, rf1, and the second principal radius
of curvature, rf2, is less than one. In at least one embodiment, a
ratio of the first principal radius of curvature, rf1, and the
second principal radius of curvature, rf2, is greater than one.
[0037] Should the first principal radius of curvature, rf1, of the
first ball member first portion 110 be larger than the first
principal radius of curvature, rt1, of the first line segment 82
there is a single point of contact at the first ball-trunnion
contact patch 114. The single point of contact at the first
ball-trunnion contact patch 114 reduces friction between the
trunnion 72 and the ball set 34 via the first ball member 90. The
reduction in friction improves noise, vibration, harshness (NVH)
performance of the vehicle, such as vehicle shudder.
[0038] The first outer surface 102 is disposed opposite the first
inner surface 100. The first outer surface 102 may be a crowned or
substantially straight surface up to an including a straight
portion that engages a rolling element of the plurality of rolling
elements 94. The substantially straight surface up to and including
a straight portion that tapers towards the trunnion axis 76 or an
axis of the ball set 34 such that the first outer surface 102 is
inclined or declined with respect to the trunnion axis 76 or an
axis of the ball set 34. The first outer surface 102 has a surface
texture that meets an Rsk value of less than zero.
[0039] The second ball member 92 has a second inner surface 120 and
a second outer surface 122. The second inner surface 120 is
disposed opposite the second outer surface 122. The second inner
surface 120 may be a crowned or substantially straight surface up
to an including a straight portion that engages a rolling element
of the plurality of rolling elements 94. The second inner surface
120 has a surface texture that meets an Rsk value of less than
zero.
[0040] A pair of thrust shoulders (or a flange) is disposed at
opposite ends of the second inner surface of 120. The pair of
thrust shoulders project radially inward from the second inner
surface 120 towards the trunnion axis 76. The pair of thrust
shoulders aid in axially retaining a rolling element of the
plurality of rolling elements 94.
[0041] The second outer surface 122 is a non-symmetric piecewise
continuous surface having a convex radius of curvature or a
non-symmetric piecewise continuous profile (convex profile) that
engages the first sidewall 42 of the guide channel 40 having a
concave profile. The second outer surface 122 may be a crowned or
substantially straight surface up to an including a straight
portion that engages a rolling element of the plurality of rolling
elements 94. The substantially straight surface up to and including
a straight portion that tapers towards the trunnion axis 76 such
that the second outer surface 122 is inclined or declined with
respect to the trunnion axis 76 or an axis of the ball set 34. The
second outer surface 122 has a surface texture that meets an Rsk
value of less than zero. The convex profile of the second outer
surface 122 is defined by a second outer surface first portion 130,
a second outer surface second portion 132, and a second outer
surface third portion 134. The convex profile of the second outer
surface 122 may include a truncated toroid, truncated ellipsoid,
truncated sphere, a piecewise continuous profile revolved around
the trunnion axis 76 or a combination thereof.
[0042] The second outer surface first portion 130 is disposed
adjacent to and between a top surface of the second ball member 92
and the second outer surface second portion 132. The second outer
surface first portion 130 has a second outer surface first portion
radius of curvature, ro1. A ball transition region 136 extends
between the second outer surface first portion 130 and the second
outer surface second portion 132. The ball transition region 136
provides a substantially smooth or continuous transition between
the second outer surface first portion 130 and the second outer
surface second portion 132. The second outer surface second portion
132 is disposed between the second outer surface first portion 130
and the second outer surface third portion 134. The second outer
surface second portion 132 has a second outer surface second
portion 132 radius of curvature, ro2. The second outer surface
third portion 134 is disposed adjacent to and between the second
outer surface second portion 132 and a bottom surface of the second
ball member 92. The second outer surface third portion 134 has a
second outer surface third portion radius of curvature, ro3.
[0043] The second outer surface second portion radius of curvature,
ro2 has a large radius of curvature, such that the second outer
surface second portion 132 is a substantially straight portion. The
second outer surface first portion radius of curvature, ro1, and
the second outer surface third portion radius of curvature, ro3,
substantially defines the generally convex profile of the second
outer surface 122. An absolute value of a ratio between the second
outer surface third portion radius of curvature, ro3, and the first
outer surface second portion radius of curvature, ro1, may be
greater or less than one.
[0044] The second outer surface first portion 130 is disposed
proximate the first sidewall portion 50. The second outer surface
second portion 132 is disposed proximate the second sidewall
portion 52. The second outer surface second portion 132 engages the
second sidewall portion 52. The engagement between the second outer
surface second portion 132 and the second sidewall portion 52
defines a second ball-sidewall contact patch 140. The second outer
surface third portion 134 is disposed proximate the third sidewall
portion 54. The second outer surface third portion 134 engages the
third sidewall portion 54. The engagement between the second outer
surface third portion 134 and the third sidewall portion 54 defines
a third ball-sidewall contact patch 142.
[0045] Should the second outer surface first portion radius of
curvature, ro1 of the second outer surface first portion 130 be
less than the first sidewall portion radius of curvature, rs1, of
the first sidewall 42, there is a clearance condition proximate the
ball transition region 138.
[0046] Should the second outer surface second portion radius of
curvature, ro2, of the second outer surface second portion 132 be
less than the second sidewall portion radius of curvature, rs2, of
the second sidewall portion 52, there is a clearance condition at
the ball transition region 136. The single point of contact at the
second ball-sidewall contact patch 140 further reduces friction
between the guide channel 40 and the ball set 34 via the second
ball member 92. The reduction in friction improves NVH performance
of the vehicle during events in which the ball set 34 rotates about
or translates axially along the trunnion axis 76.
[0047] The second outer surface 122 is spaced apart from the first
sidewall 42 proximate the transition region 56 of the first
sidewall 42 and the ball transition region 136 of the second outer
surface 122. In at least one embodiment, an undercut 146 is added
to the second outer surface 122 to ensure that the second outer
surface 122 is spaced apart from the first sidewall 42 proximate
the transition region 56 and the ball transition region 136. The
undercut 146 is sized such that the amount of clearance between the
second outer surface 122 and the first sidewall 42 exceeds an
amount of elastic deformation of at least one of a ball set 34
component or a housing 30 component proximate the transition
regions when the constant velocity joint 10 is under design
torques. The second outer surface third portion 134 is spaced apart
from the third sidewall portion 54 such that the third sidewall
portion 54 does not engage the second outer surface third portion
134. The second outer surface third portion 134 is spaced apart
from the third sidewall portion 54
[0048] In at least one embodiment, the second outer surface 122
includes a cylindrical section 150. The cylindrical section 150 is
disposed between a top surface of the second ball member 152 and a
bottom surface of the second ball member 154. The top surface of
the second ball member 152 is a non-cylindrical portion. The bottom
surface of the second ball member hundred and 54 is a
non-cylindrical portion. The cylindrical section 150 minimum
height, H, is satisfied by the following equation:
H>BCD*(1-cos(theta)) Equation(1)
[0049] In Equation (1) BCD is a ball circle diameter of the spider
32 and theta is a maximum tripot constant velocity joint angle. The
housing 30 has a ball circle diameter. Should the ball circle
diameter of the spider 32 but substantially co linear with the ball
circle diameter of the housing, loading of the tripot constant
velocity joint is through the center of the ball set 34. The
combination of the radii of first sidewall portion radius of
curvature, rs1, the second sidewall portion radius of curvature,
rs2, the third sidewall portion radius of curvature, rs3; the radii
of second outer surface first portion radius of curvature, ro1, the
second outer surface second portion radius of curvature, ro2, the
second outer surface third portion radius of curvature, ro3; the
first principal radius of curvature, rt1, the second principal
radius of curvature, rt2; or the first ball member first portion
radius of curvature, rf1, and the first ball member second portion
radius of curvature, rf2, permits the tripot constant velocity
joint 10 to be less sensitive or more robust to variations or
offsets between the housing ball circle diameter and the spider
ball circle diameter due to manufacturing variances such that
loading may be through the center of the ball set 34.
[0050] The plurality of rolling elements 94 is disposed between the
first outer surface 102 and the second inner surface 120. The
plurality of rolling elements 94 may be balls, cones, rollers,
needles, or the like.
[0051] Should the first shaft member 12 and the housing 30 and or
the second shaft member 14 and the spider 32 be articulated to a
joint angle greater than an articulation threshold, i.e. an over
articulation condition, at least a portion of the ball set 34
engages the protrusion 60 and the first ball member 90 detaches
from the trunnion 72. Upon the first shaft member 12 and the
housing 30 and or the second shaft member 14 and the spider 32
return from the over articulation condition and be articulated to a
joint angle within the articulation threshold, the first ball
member 90 engage the protrusion 60 such that the first ball member
90 (the ball set 34) reattaches to the trunnion 72 should the first
ball member 90 become detached from the trunnion 72. The protrusion
60 also inhibits tipping of the ball set 34 due to articulation of
the constant velocity joint 10 proximate or greater than the
articulation threshold.
[0052] As shown in FIG. 5C the plurality of rolling elements number
of 94 are not be provided. In such an embodiment, the first outer
surface 102 is disposed proximate and engage the second inner
surface 120. Referring to FIG. 5C, an exemplary constant velocity
joint 10 is shown. The constant velocity joint 10 includes a
housing 30, a spider 32, and a ball set 34, unlike previous
embodiments the ball set 34 may not include a second ball member 92
or a plurality of rolling elements 94. The housing 30 has a first
sidewall concave portion, a second sidewall straight portion, and a
third sidewall concave portion. A ratio between the radii of
curvature of the second sidewall straight portion and at least one
of the first sidewall concave portion and the third sidewall
concave portion is greater than one.
[0053] The ball set 34 includes a first ball member 160 having a
first inner surface 100 and a first outer surface 170. The first
inner surface 100 may be a crowned surface having a substantially
straight portion and a crowned or convex portion adjacent to the
substantially straight portion. The first inner surface 100 engages
the first line segment 82. The engagement between the first ball
member first portion 110 and the first line segment 82 defines a
first ball-trunnion contact patch 114. The first ball member first
portion 110 has a first principal radius of curvature, rf1.
[0054] The first outer surface 170 is a non-symmetric piecewise
continuous surface having a convex profile that engages the first
sidewall 42 of the guide channel 40 having a concave profile. The
first outer surface 170 has a surface texture that meets an Rsk
value of less than zero. The convex profile of the first outer
surface 170 is defined by a first outer surface first segment 180,
a first outer surface second segment 182, and a first outer surface
third segment 184. The convex profile of the first outer surface
170 may include a truncated toroid, truncated ellipsoid, truncated
spheroid or a combination thereof.
[0055] The first outer surface first segment 180 is disposed
adjacent to and between a top surface of the first ball member 160
and the first outer surface second segment 182. The first outer
surface first segment 180 has a first outer surface first segment
radius of curvature, rfs1. A ball transition region 190 extends
between the first outer surface first segment 180 and the first
outer surface second segment 182. The ball transition region 190
provides a substantially smooth or continuous transition between
the first outer surface first segment 180 and the first outer
surface second segment 182. The first outer surface second segment
182 is disposed between the first outer surface first segment 180
and the first outer surface third segment 184. The first outer
surface second segment 182 has a first outer surface second segment
radius of curvature, rfs2. The first outer surface third segment
184 is disposed adjacent to and between the first outer surface
second segment 182 and a bottom surface of the first ball member
160. The first outer surface third segment 184 has a first outer
surface third segment radius of curvature, rfs3.
[0056] The first outer surface first segment radius of curvature,
rfs1 has an infinite radius of curvature. The first outer surface
second segment radius of curvature, rfs2, and the first outer
surface third segment radius of curvature, rfs3, substantially
defines the generally convex profile of the first outer surface
170. The first outer surface third segment radius of curvature,
rfs3, is greater than the first outer surface second segment radius
of curvature, rfs2. An absolute value of a ratio between the first
outer surface third segment radius of curvature, rfs3, and the
first outer surface second segment radius of curvature, rfs2, may
be greater than one.
[0057] The first outer surface first segment 180 is disposed
proximate the first sidewall portion 50. The first outer surface
first segment 180 engages the first sidewall portion 50. The
engagement between the first outer surface first segment 180 and
the first sidewall portion 50 defines a first contact region 186.
The first outer surface second segment 182 is disposed proximate
the second sidewall portion 52. The first outer surface second
segment 182 engages the second sidewall portion 52. The engagement
between the first outer surface second segment 182 and the second
sidewall portion 52 defines a second contact region 188. The first
outer surface third segment 184 is disposed proximate the third
sidewall portion 54. The first outer surface third segment 184 is
spaced apart from and does not engage the third sidewall portion
54.
[0058] Should the first outer surface first segment radius of
curvature, rfs1 of the first outer surface first segment 180 be
less than the first sidewall portion radius of curvature, rs1, of
the first sidewall 42, there is a single point of contact at the
first contact region 186. The single point of contact at the first
contact region 186 reduces friction between the guide channel 40
and the ball set 34 via the first ball member 160. The reduction in
friction improves NVH performance of the vehicle during events in
which the ball set 34 rotates about or translates axially along the
trunnion axis 76.
[0059] Should the first outer surface second segment radius of
curvature, rfs2, of the first outer surface second segment 182 be
less than the second sidewall portion radius of curvature, rs2, of
the second sidewall portion 52, there is a single point of contact
at the second contact region 188. The single point of contact at
the second contact region 188 further reduces friction between the
guide channel 40 and the ball set 34 via the first ball member 160.
The reduction in friction improves NVH performance of the vehicle
during events in which the ball set 34 rotates about or translates
axially along the trunnion axis 76.
[0060] The first outer surface 170 is spaced apart from the first
sidewall 42 proximate the transition region 56 of the first
sidewall 42 and the ball transition region 190 of the first outer
surface 170. In at least one embodiment, an undercut 196 is added
to the first outer surface 170 to ensure that the first outer
surface 170 is spaced apart from the first sidewall 42 proximate
the transition region 56 and the ball transition region 190. The
undercut 196 is sized such that the amount of clearance between the
first outer surface 170 and the first sidewall 42 exceeds an amount
of elastic deformation of at least one of a ball set 34 component
or a housing 30 component proximate the transition regions when the
constant velocity joint 10 is under design torques. The first outer
surface third segment 184 is spaced apart from the third sidewall
portion 54 such that the third sidewall portion 54 does not engage
the first outer surface third segment 184. The first outer surface
third segment 184 is spaced apart from the third sidewall portion
54
[0061] In at least one embodiment, the first outer surface third
segment 184 includes a cylindrical section 200. The cylindrical
section 200 is disposed between a top surface 172 of the first ball
member 160 and a bottom surface 174 of the first ball member 160.
The top surface 172 of the first ball member 160 is a
non-cylindrical portion. The bottom surface 174 of the first ball
member 160 is a non-cylindrical portion. The cylindrical section
200 has a minimum height, H, that is satisfied by Equation (1).
[0062] A lubricant may be applied to the constant velocity joint
10. The lubricant aids in reducing friction or improve NVH response
of the constant velocity joint 10. The overall coefficient of
friction of the tripot constant velocity joint 10 as a result of
the lubricant is less than 0.1. The lubricant may contain no solid
additives to further reduce friction between components of the
constant velocity joint 10. In at least one embodiment, the
lubricant contains molybdenum based solid additives with the median
particle size between 0.5-100 microns.
[0063] While the invention has been described in detail in
connection with only a limited number of embodiments, it should be
readily understood that the invention is not limited to such
disclosed embodiments. Rather, the invention can be modified to
incorporate any number of variations, alterations, substitutions or
equivalent arrangements not heretofore described, but which are
commensurate with the spirit and scope of the invention.
Additionally, while various embodiments of the invention have been
described, it is to be understood that aspects of the invention may
include only some of the described embodiments. Accordingly, the
invention is not to be seen as limited by the foregoing
description.
* * * * *