WO2018222660A1

WO2018222660A1 - Components and assemblies for a ball-type continuously variable planetary transmission

Info

Publication number: WO2018222660A1
Application number: PCT/US2018/035043
Authority: WO
Inventors: Ryan D. Nelms; Benjamin L. POWELL
Original assignee: Dana Limited
Priority date: 2017-05-31
Filing date: 2018-05-30
Publication date: 2018-12-06

Abstract

A CVT having a plurality of balls, each ball having a tiltable axis of rotation and in contact with a first traction ring and a second traction ring, including: a shaft aligned along a longitudinal axis and positioned inward of the balls, the first traction ring and the second traction ring; a carrier assembly coupled to each ball having a first carrier member and a second carrier member coupled to the first carrier member; a first cam driver coupled to the first traction ring adapted to receive a rotational power and coupled to the first carrier member; a thrust bearing assembly coupled to the cam driver and to the shaft; and a lubricant sleeve assembly coupled to the first carrier member and the shaft having lubricant passages, a first shielded bearing on one side of the passages, and a second shielded bearing on an opposite side of the passages.

Description

COMPONENTS AND ASSEMBLIES FOR A BALL-TYPE CONTINUOUSLY VARIABLE PLANETARY TRANSMISSION

RELATED APPLICATION

The present application claims the benefit of and priority to U.S.

Provisional Patent Application No. 62/513,171 filed on May 31 , 2017, which is hereby incorporated in by reference.

BACKGROUND

Automatic and manual transmissions are commonly used on motor vehicles. Such transmissions have become increasingly complicated since the engine speed has to be adjusted to limit fuel consumption and the emissions of the vehicle. A vehicle having a driveline including a tilting ball variator allows an operator of the vehicle or a control system of the vehicle to vary a drive ratio in a stepless manner. A variator is an element of a Continuously Variable Transmission (CVT) or an Infinitely Variable Transmission (IVT).

Transmissions that use a variator can decrease the transmission's gear ratio as engine speed increases. This keeps the engine within its optimal efficiency while gaining ground speed, or trading speed for torque during hill climbing, for example. Efficiency in this case can be fuel efficiency, decreasing fuel consumption and emissions output, or power efficiency, allowing the engine to produce its maximum power over a wide range of speeds. That is, the variator keeps the engine turning at constant RPMs over a wide range of vehicle speeds.

SUMMARY

Provided herein is a continuously variable transmission (CVT) having a plurality of balls, each ball having a tiltable axis of rotation, each ball in contact with a first traction ring and a second traction ring, the CVT including: a rotatable shaft aligned along a longitudinal axis of the CVT, the shaft positioned radially inward of the balls, the first traction ring and the second traction ring; a carrier assembly operably coupled to each ball, the carrier assembly including a first carrier member arranged coaxial to the shaft, and a second carrier member operably coupled to the first carrier member, wherein the second carrier member is configured to rotate relative to the first carrier member and the second carrier member is arranged coaxial to the shaft; a first cam driver operably coupled to the first traction ring, wherein the first cam driver is adapted to receive a rotational power and is operably coupled to the first carrier member; a thrust bearing assembly coupled to the cam driver and to the shaft; and a lubricant sleeve assembly coupled to the first carrier member and the shaft, wherein the lubricant sleeve assembly comprises a number of radial lubricant passages, a first shielded bearing located on one side of the radial lubricant passages, and a second shielded bearing located on an opposite side of the radial lubricant passages.

In some embodiments, the first traction ring is an annular ring having a cam surface on one side of the annular ring and a traction surface located at another location on the annular ring.

In some embodiments, the position of the cam surface with respect to the traction surface corresponds to aligning a resultant center of momentum formed by a cam force acting on the cam surface and a normal contact force acting on the traction surface with a geometric center of the cross section of the annular ring.

In some embodiments, the carrier assembly further includes a plurality of inserts pressed into the second carrier member, wherein the inserts are positioned in an array around an outer periphery of the second carrier member,

In some embodiments, each insert has a head in contact with the first carrier member, wherein the head of the insert positions the first carrier member with respect to the second carrier member in an axial direction.

In some embodiments, each insert is made of a low friction material. In some embodiments, the first carrier member is provided with a first array of carrier lubricant passages, each carrier lubricant passage in fluid communication with the radial lubricant passages of the lubricant sleeve, wherein each carrier lubricant passage extends radially outward from an inner diameter of the first carrier member and intersects an orifice passage at a radially outward location, and wherein the orifice passage is provided with a traction ring orifice on one end and an idler ring orifice at an opposite end. In some embodiments, the second carrier member is provided with a second array of carrier lubricant passages, each carrier lubricant passage in fluid communication with the radial lubricant passages of the lubricant sleeve, wherein each carrier lubricant passage extends radially outward from an inner diameter of the second carrier member and intersects an orifice passage at a radially outward location, and wherein the orifice passage is provided with a traction ring orifice on one end and an idler ring orifice at an opposite end.

In some embodiments the CVT further includes an idler assembly in contact with each ball at a radially inward location, the idler assembly including a first idler ring, a second idler ring, an idler bearing coupled to the first idler ring, and an idler race coupled to the idler bearing and the second idler ring.

In some embodiments the CVT further includes an idler support tube positioned between the idler race and the shaft.

In some embodiments, the idler support tube is coupled to a first radial bearing, the first radial bearing coupled to the lubricant sleeve.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

Novel features of the embodiments are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the disclosure are utilized, and the accompanying drawings of which:

Figure 1 is a side sectional view of a ball-type variator.

Figure 2 is a plan view of a carrier member that is used in the variator of

Figure 1 .

Figure 3 is an illustrative view of different tilt positions of the ball-type variator of Figure 1 . Figure 4 is a plan view of a ball-type continuously variable transmission depicting a number of section views with respect to a longitudinal axis.

Figure 5 is a cross-sectional view "A-A" of the ball-type continuously variable transmission of Figure 4.

Figure 6 is a cross-sectional view of a traction ring used in the ball-type continuously variable transmission of Figure 4.

Figure 7 is a cross-sectional view "B-B" of the ball-type continuously variable transmission of Figure 4.

Figure 8 is a cross-sectional view "C-C" of the ball-type continuously variable transmission of Figure 4.

Figure 9 is a cross-section detail view "G" of certain components of the ball-type continuously variable transmission of Figure 4.

Figure 10 is a cross-section detail view "D" of certain components of the ball-type continuously variable transmission of Figure 4.

Figure 11 is a cross-section detail view "E" of certain components of the ball-type continuously variable transmission of Figure 4.

Figure 12 is cross-sectional view of certain components of the ball-type continuously variable transmission of Figure 4.

Figure 13 is cross-sectional view of certain components that are optionally used in the ball-type continuously variable transmission of Figure 4.

Figure 14 is cross-sectional view of certain components that are optionally used in the ball-type continuously variable transmission of Figure 4.

Figure 15 is cross-sectional view of certain components that are optionally used in the ball-type continuously variable transmission of Figure 4.

Figure 16 is a cross-sectional view of a thrust bearing assembly used in the ball-type continuously variable transmission of Figure 4.

Figure 7 is a cross-sectional view of another thrust bearing assembly optionally used in the ball-type continuously variable transmission of Figure 4.

DETAILED DESCRIPTION OF THE DRAWINGS

Provided herein are configurations of CVTs based on ball-type variators, also known as CVP, for continuously variable planetary. Basic concepts of a ball-type Continuously Variable Transmissions are described in United States Patent No. 8,469,856 and United States Patent No. 8,870,711 incorporated herein by reference in their entirety. Such a CVT, adapted herein as described throughout this specification, includes a number of balls (planets, spheres) 1 , depending on the application, two ring (disc) assemblies with a conical surface contact with the balls 1 , as a first (input) traction ring 2 and a second (output) traction ring 3, and an idler (sun) assembly 4 as shown on FIG. 1. The balls 1 are mounted on tiltable axles 5, themselves held in a carrier (stator, cage) assembly having a first carrier member 6 operably coupled to a second carrier member 7. The first carrier member 6 rotates with respect to the second carrier member 7, and vice versa. In some embodiments, the first carrier member 6 is substantially fixed from rotation while the second carrier member 7 is

configured to rotate with respect to the first carrier member, and vice versa. In one embodiment, the first carrier member 6 is provided with a number of radial guide slots 8. The second carrier member 7 is provided with a number of radially offset guide slots 9. The radial guide slots 8 and the radially offset guide slots 9 are adapted to guide the tiltable axles 5. The axles 5 are adjusted to achieve a desired ratio of input speed to output speed during operation of the CVT. In some embodiments, adjustment of the axles 5 involves control of the position of the first carrier member and the second carrier member to impart a tilting of the axles 5 and thereby adjusts the speed ratio of the variator. Other types of ball CVTs also exist, like the one produced by Milner, but are slightly different.

In some embodiments, the conical surfaces of the first traction ring 2 and the second traction ring 3 have angled contact surfaces with respect to the balls 1 in the range of 30 to 45 degrees. The typical traction surface profile is typically described as a radius, R, of concave or convex nature between 50% conformal and 500% convex, including a straight (0% convex).

Likewise, in some embodiments, the idler assembly 4 includes rings in contact with each balls 1 having angled contact surfaces with respect to the balls 1 in the range of 7 to 13 degrees. The typical traction surface shape is between 50% conformal and 500% convex including straight (0% convex).

The working principle of such a CVP of FIG. 1 is shown on FIG. 2. The CVP itself works with a traction fluid. The lubricant (traction fluid) between the ball and the conical rings acts as a solid at high pressure, transferring the power from the input ring, through the balls, to the output ring. By tilting the balls' axes, the ratio is changed between input and output. When the axis is horizontal the ratio is one, illustrated in FIG. 3, when the axis is tilted the distance between the axis and the contact point change, modifying the overall ratio. All the balls' axes are tilted at the same time with a mechanism included in the carrier and/or idler. Embodiments disclosed here are related to the control of a variator and/or a CVT using generally spherical planets each having a tiltable axis of rotation that is capable of being adjusted to achieve a desired ratio of input speed to output speed during operation. In some embodiments, adjustment of said axis of rotation involves angular misalignment of the planet axis in a first plane in order to achieve an angular adjustment of the planet axis in a second plane that is substantially perpendicular to the first plane, thereby adjusting the speed ratio of the variator. The angular

misalignment in the first plane is referred to here as "skew", "skew angle", and/or "skew condition". In one embodiment, a control system coordinates the use of a skew angle to generate forces between certain contacting components in the variator that will tilt the planet axis of rotation. The tilting of the planet axis of rotation adjusts the speed ratio of the variator.

As used here, the terms "operationally connected", "operationally coupled", "operationally linked", "operably connected", "operably coupled", "operably Jinked," and like terms, refer to a relationship (mechanical, linkage, coupling, etc.) between elements whereby operation of one element results in a corresponding, following, or simultaneous operation or actuation of a second element. It is noted that in using said terms to describe the embodiments, specific structures or mechanisms that link or couple the elements are typically described. However, unless otherwise specifically stated, when one of said terms is used, the term indicates that the actual linkage or coupling may take a variety of forms, which in certain instances will be readily apparent to a person of ordinary skill in the relevant technology.

For description purposes, the term "radial" is used here to indicate a direction or position that is perpendicular relative to a longitudinal axis of a transmission or variator. The term "axial" as used here refers to a direction or position along an axis that is parallel to a main or longitudinal axis of a transmission or variator. For clarity and conciseness, at times similar components labeled similarly (for example, lubricant sleeve assembly 22A and lubricant sleeve assembly 22B) will be referred to collectively by a single label (for example, lubricant sleeve assembly 22).

It should be noted that reference herein to "traction" does not exclude applications where the dominant or exclusive mode of power transfer is through "friction." Without attempting to establish a categorical difference between traction and friction drives here, generally these may be understood as different regimes of power transfer. Traction drives usually involve the transfer of power between two elements by shear forces in a thin fluid layer trapped between the elements. The fluids used in these applications usually exhibit traction coefficients greater than conventional mineral oils. The traction coefficient (μ) represents the maximum available traction forces which would be available at the interfaces of the contacting components and is a measure of the maximum available drive torque.

In some embodiments, the traction coefficient is a design parameter in the range of 0.3 to 0.6.

Friction drives generally relate to transferring power between two elements by frictional forces between the elements. For the purposes of this disclosure, it should be understood that the CVTs described here may operate in both tractive and frictional applications. As a general matter, the traction coefficient μ is a function of the traction fluid properties, the normal force at the contact area, and the velocity of the traction fluid in the contact area, among other things. For a given traction fluid, the traction coefficient μ increases with increasing relative velocities of components, until the traction coefficient μ reaches a maximum capacity after which the traction coefficient μ decays. The condition of exceeding the maximum capacity of the traction fluid is often referred to as "gross slip condition".

As used herein, "creep", "ratio droop", or "slip" is the discrete local motion of a body relative to another and is exemplified by the relative velocities of rolling contact components such as the mechanism described herein. In traction drives, the transfer of power from a driving element to a driven element via a traction interface requires creep. Usually, creep in the direction of power transfer is referred to as "creep in the rolling direction." Sometimes the driving and driven elements experience creep in a direction orthogonal to the power transfer direction, in such a case this component of creep is referred to as "transverse creep."

For description purposes, the terms "prime mover", "engine," and like terms, are used herein to indicate a power source. Said power source may be fueled by energy sources including hydrocarbon, electrical, biomass, solar, geothermal, hydraulic, and/or pneumatic to name but a few. Although described in a vehicle or automotive application, one skilled in the art will recognize the broader applications for this technology and the use of alternative power sources for driving a transmission using this technology.

Referring now to FIGS. 4-17, in some embodiments, a continuously variable transmission (CVT) 10 is configured in a similar manner as the variator depicted in FIGS. 1-3. For description purposes, only the differences between the CVT 10 and the variator of FIGS. 1-3 will be described. As a visual aid to depict certain components of the CVT 10, orientation of cross-sectional views are provided with respect to the longitudinal axis in FIG. 4. The longitudinal axis is arranged perpendicular to the plane of the page when viewed in FIG. 4.

Referring now to FIG. 5, in some embodiments, the CVT 10 is provided with a main shaft 11 that is arranged along the longitudinal axis. A thrust bearing assembly 12 is operably coupled to the shaft 1 1 .

In some embodiments, the CVT 0 is adapted to receive a rotational input power on a first cam driver 13. The first cam driver 3 is coupled to a first array of ball cam bearings 14. The first array of ball cam bearings 14 are configured to cooperate with a number ramped surfaces provided on the first cam driver 3 and/or a first traction ring 15 to provide torque dependent axial force, sometimes referred to as "clamping force", "clamping", or "axial clamp force". The first traction ring 15 is in contact with a number of balls 1.

In some embodiments, the CVT 10 is provided with a second traction ring 16 in contact with the balls 1 . The second traction ring 16 is coupled to a second array of ball cam bearings 17. The ball cam bearings 17 are configured to cooperate with a number of ramped surfaces provided on the second traction ring 16 and/or a second cam driver 18. The second cam driver 18 is coupled to the shaft 1 1.

In some embodiments, the second cam driver 18 is coupled to the shaft 1 1 with a set of splines.

The shaft 1 1 is adapted to transmit a power output from the CVT 10.

In some embodiments, the balls 1 are operably coupled to a carrier assembly 19. The carrier assembly 19 is provided with a first carrier member 20 and a second carrier member 21. The carrier assembly 19 is coaxial with the shaft 1 1 .

In some embodiments, the carrier assembly 19 is operably coupled to the shaft 1 1 with a lubricant sleeve assembly 22.

In some embodiments, the CVT 10 is provided with an idler assembly 24 arranged radially inward of the balls 1 . The idler assembly 24 is optionally configured similar to the idler assemblies described in Patent Cooperation Treaty Patent Application No. PCT/US18/032032, which is hereby incorporated by reference.

In some embodiments of the CVT 10, it is beneficial to balance the movement of the balls 1 with respect to the ball axles. By balancing the movement of the balls 1 , the clearance between the balls 1 to surrounding components such as the carrier assembly 19 can be reduced. Reducing the movement of the balls 1 can also reduce the clearance between the first cam driver 13, the second cam driver 18 and the carrier assembly 19 thereby reducing the overall axial length of the CVT 10. Additionally, balancing the movement of the balls 1 minimizes shutter or oscillation of the balls when the CVT operates around a speed ratio of 1 .

In the embodiments provided herein, the active cam driver is the cam driver with the highest torque. The cams drivers will turn on/off depending on which carrier member is the higher torque causing the ball 1 to move back and forth. The stiffer the CVT system, the lower the movement.

Balancing the components attached to first traction ring 15 cams with the components on the second traction ring 16 side thereby maintains equal clearances on both sides of the CVT. In some embodiments, the shaft 1 1 is a having a hollow shaft portion.

In some embodiments, the hollow shaft portion is formed having a maximum length to diameter ratio of about 14.

Passing now to FIG. 6, certain design aspects of the first traction ring 15 and/or the second traction ring 16 will be described. For clarity and

conciseness, the first traction ring 15 is used as illustrative example, and it is appreciated that the features described in reference to the first traction ring 15 are applicable to the second traction ring 16 as well as components of the idler assembly 24.

In some embodiments, the first traction ring 15 is a generally annular ring having a traction surface 25 on one side thereof and a cam surface 28 on the other side thereof.

In some embodiments, the first traction ring 15 is an annular ring having a cam surface 28 on one side of the annular ring and a traction surface located at another location on the annular ring.

During operation of the CVT 10, a contact normal force 26 ("Fcontact") is transmitted to the traction surface 25 through contact with the balls 1. For description purposes, a first construction line 27 is depicted in Figure 6 corresponding to the orientation of the direction of the contact normal force 26 with respect to the first traction ring 15. An axial force 29 is transmitted to the cam surface 28 through contact with the ball cam bearings 14. For description purposes, a second construction line 30 is depicted in Figure 6 corresponding to the orientation of the direction of the axial force 29 with respect to the first traction ring 15. An intersection 31 of the first construction line 27 and the second construction line 30 identifies the center of momentum of a resultant moment formed by the contact normal force 26 and the axial force 29.

It should be appreciated that the dimensions of the first traction ring 15 are configurable to position the intersection 31 with respect to a geometric center of the first traction ring 5, wherein the geometric center is depicted by the intersection of a third construction line 32 and a fourth construction line 33, to thereby minimize the resultant moment and increase the effective

mechanical stiffness of the first traction ring 15 during operation. Turning now to FIGS. 7-9, certain aspects of the carrier assembly 19 will be described in reference to cross-sectional views diagrammed in Figure 4.

Referring now to FIG. 7, in some embodiments, the carrier assembly 19 is operably coupled to the main shaft 11 in such a way as to facilitate the flow of a traction fluid from an inner bore of the main shaft 11 to traction

components of the CVT 10. The main shaft 11 is provided with a number of shaft lubricant passages 40 configured to intersect the hollow bore of the main shaft 11 and an outer perimeter of the main shaft 11. The shaft lubricant passages 40 are generally aligned with a first lubricant sleeve assembly 22A and a second lubricant sleeve assembly 22B. The first lubricant sleeve assembly 22A is configured to operably coupled to the first carrier member 20. The second lubricant sleeve assembly 22B is operably coupled to the second carrier member 21. The first lubricant sleeve assembly 22A is provided with a sleeve lubricant passage 41 arranged to be in fluid communication with the shaft lubricant passages 40. The sleeve lubricant passage 41 is arranged to be in fluid communication with a number of carrier lubricant passages 42 formed on the interior of the first carrier member 20.

In some embodiments, the carrier lubricant passages 42 are aligned with the balls 1.

Each carrier lubricant passage 42 intersects an orifice passage 43. The orifice passage 43 is aligned to supply pressurized fluid through an array of first traction ring orifices 44 to the contacting locations between the balls 1 and the first traction ring 15, and supply pressurized fluid through an array of first idler ring orifices 45 to the idler assembly 24.

In some embodiments, each carrier lubricant passage 42 extends radially outward from an inner diameter of the first carrier member 20 and intersects an orifice passage 43 at a radially outward location. The orifice passage 43 is provided with a traction ring orifice 44 on one end and an idler ring orifice 45 at an opposite end.

In some embodiments, the second lubricant sleeve assembly 22B is provided with a sleeve lubricant passage 46 arranged to be in fluid

communication with the shaft lubricant passages 40. The sleeve lubricant passage 46 is arranged to be in fluid communication with a number of carrier lubricant passages 47 formed on the interior of the second carrier member 21 .

In some embodiments, each carrier lubricant passage 47 extends radially outward from an inner diameter of the second carrier member 21 and intersects an orifice passage 48 at a radially outward location, and wherein the orifice passage 48 is provided with a traction ring orifice on one end and an idler ring orifice at an opposite end.

In some embodiments, the carrier lubricant passages 47 are aligned with the balls 1 .

Each carrier lubricant passage 47 intersects an orifice passage 48. The orifice passage 48 is aligned to supply pressurized fluid through an array of second traction ring orifices 49 to the contacting locations between the balls 1 and the second traction ring 16, and supply pressurized fluid through an array of second idler ring orifices 50 to the idler assembly 24.

Referring specifically to FIG. 8, in some embodiments, a first annular channel 51 is formed on the first lubricant sleeve assembly 22A. A second annular channel 52 is formed on the second lubricant sleeve assembly 22B. The second annular channel 52 facilitates the distribution of the fluid to the carrier lubricant passage 47 to provide tolerance to the alignment between the sleeve lubricant passage 46 and the carrier lubricant passage 40 once assembled.

In some embodiments, the first lubricant sleeve assembly 22A is provided with an idler bearing lubricant passage 59. The idler bearing lubricant passage 59 is arranged to be in fluid communication with the sleeve lubricant passage 46 to thereby supply a lubricant flow to the idler assembly 24.

Referring to FIG. 9, in some embodiments, the first lubricant sleeve assembly 22 is provided with a lubricant sleeve 55 that is supported on the main shaft 1 1 by a first bearing 56 and a second bearing 57.

In some embodiments, the first bearing 56 and the second bearing 57 are shielded bearings that are adapted to provide a fluid labyrinth to the interface between the lubricant sleeve 55 and the main shaft 1 .

In other embodiments, typical shaft seals are used to seal the interface between the lubricant sleeve 55 and the main shaft 1 1 . In some embodiments, the lubricant sleeve 55 is adapted to provide support to a radial bearing 58. The radial bearing 58 is optionally coupled to the idler assembly 24.

In some embodiments, the lubricant sleeve 55 is pressed onto the first carrier 20.

In some embodiments, staking processes are performed to retain the coupling between the first carrier 20 and the lubricant sleeve 55.

Turning now to FIG. 10, in some embodiments, the first carrier member 20 is operably coupled to the second carrier member 21 with a number of shoulder bolts 60 arrayed about an outer periphery of the carrier assembly 19. The shoulder bolts 60 attach to the second carrier member 21 at a threaded bore 61 formed on the second carrier member 21 . The shoulder bolt 60 is guided in slots 62 formed in the first carrier member 20. The slots 62 are sized appropriately to provide a physical limit to the relative rotation and axial separation of the first carrier member 20 with respect to the second carrier member 21.

Referring now to FIG. 1 1 , in some embodiments, the first carrier member 20 is positioned axially with respect to the second carrier member 21 with a number of inserts 63.

In some embodiments, the inserts 63 are made of a plastic material.

In other embodiments, the inserts 63 are made of any low friction material.

The inserts 63 are pressed into holes formed on the second carrier member 21.

In some embodiments, the inserts 63 are positioned in an array around the outer periphery of the second carrier member 21.

The inserts 63 have a head 64 on one end thereof in contact with the first carrier member 20. The head 64 provides a low friction wear surface for axial spacing on which the first carrier member 20 rotates with respect to the second carrier member 21 .

Passing now to FIGS. 12-15, a variety of couplings between the idler assembly 24 and the main shaft 1 1 will be described. In some embodiments, the idler assembly 24 includes a first idler ring 70 and a second idler ring 71 , each in contact with the balls 1. The first idler ring 70 is supported by an idler bearing 72. The idler bearing 72 is coupled to an idler race 73. The idler race 73 is operably coupled to the second idler ring 71 .

In some embodiments, the idler assembly 24 is positioned axially between the first lubricant sleeve 55A and the second lubricant sleeve 55B.

In some embodiments, the idler race 73 is coupled to an idler support tube 74. The idler support tube 74 is coaxial with the main shaft 1 and is radially inward of the idler race 73. One end of the idler support tube 74 is coupled to the first lubricant sleeve 55A through a first radial ball bearing 75. A second end of the idler support tube 74 is coupled to the second lubricant sleeve 55B through a second radial ball bearing 76.

For description purposes, only the differences between FIGS. 13-15 and FIG. 12 will be described.

Turning to FIG. 13, in some embodiments, an idler support tube 80 is coupled to the idler race 73 and the main shaft 1 1 . The idler support tube 80 extends the length of the first idler ring 70 and positioned coaxial with the main shaft 1 1 and radially inward of the idler race 73. One end of the idler support tube 80 is coupled to the first lubricant sleeve 55A through a radial bearing 81.

Turning to FIG. 14, in some embodiments, the idler assembly 24 is coaxial with the main shaft 1 1 . A radially extending clearance 73A is formed between the idler race 73 and the main shaft 1 1.

Turning to FIG. 15, in some embodiments, an idler support tube 90 is coupled to the idler race 73 and the main shaft . The idler support tube 90 extends the length of the second idler ring 71 and is positioned coaxial with the main shaft 1 1 and radially inward of the idler race 73. One end of the idler support tube 90 is coupled to the second lubricant sleeve 55B through a radial bearing 91 .

Referring now to FIG. 16, in some embodiments, the thrust bearing assembly 12 includes an axial thrust ball bearing 95 coupled to the first cam driver 13. The axial thrust ball bearing 95 is coupled with an axial nut 96 that is threaded onto the main shaft 1 1 . In some embodiments, an additional radial bearing is provided to couple the first cam driver 13 to the lubricant sleeve 55.

Referring to FIG. 17, in some embodiments, the thrust bearing assembly 12 includes a deep groove axial ball bearing 97 operably coupled to the cam driver 13. The deep groove ball bearing 97 is coupled to an axial nut 98 that is threaded onto the main shaft 11.

In some embodiments, a radial bearing is provided to support the cam driver 13.

It should be noted that the description above has provided dimensions for certain components or subassemblies. The mentioned dimensions, or ranges of dimensions, are provided in order to comply as best as possible with certain legal requirements, such as best mode. However, the scope of the inventions described herein are to be determined solely by the language of the claims, and consequently, none of the mentioned dimensions is to be

considered limiting on the inventive embodiments, except in so far as any one claim makes a specified dimension, or range of thereof, a feature of the claim.

The foregoing description details certain embodiments. It will be

appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the embodiments with which that terminology is associated.

The preferred embodiments have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

WHAT IS CLAIMED IS:

1. A continuously variable transmission (CVT) having a plurality of balls, each ball having a tiltable axis of rotation, each ball in contact with a first traction ring and a second traction ring, the CVT comprising:

a rotatable shaft aligned along a longitudinal axis of the CVT, the shaft positioned radially inward of the balls, the first traction ring and the second traction ring;

a carrier assembly operably coupled to each ball, the carrier assembly comprising:

a first carrier member arranged coaxial to the shaft, and a second carrier member operably coupled to the first carrier member,

wherein the second carrier member is configured to rotate relative to the first carrier member and the second carrier member is arranged coaxial to the shaft;

a first cam driver operably coupled to the first traction ring, wherein the first cam driver is adapted to receive a rotational power and is operably coupled to the first carrier member;

a thrust bearing assembly coupled to the cam driver and to the shaft; and /

a lubricant sleeve assembly coupled to the first carrier member and the shaft, wherein the lubricant sleeve assembly comprises a number of radial lubricant passages, a first shielded bearing located on one side of the radial lubricant passages, and a second shielded bearing located on an opposite side of the radial lubricant passages.

2. The CVT of Claim 1 , wherein the first traction ring is an annular ring

having a cam surface on one side of the annular ring and a traction surface located at another location on the annular ring. The CVT of Claim 2 wherein the position of the cam surface with respect to the traction surface corresponds to aligning a resultant center of momentum formed by a cam force acting on the cam surface and a normal contact force acting on the traction surface with a geometric center of the cross section of the annular ring.

The CVT of Claim , wherein the carrier assembly further comprises a plurality of inserts pressed into the second carrier member, wherein the inserts are positioned in an array around an outer periphery of the second carrier member.

The CVT of Claim 4, wherein each insert has a head in contact with the first carrier member, wherein the head of the insert positions the first carrier member with respect to the second carrier member in an axial direction.

The CVT of Claim 4, wherein each insert is made of a low friction material.

The CVT of Claim 1 , wherein the first carrier member is provided with a first array of carrier lubricant passages, each carrier lubricant passage in fluid communication with the radial lubricant passages of the lubricant sleeve, wherein each carrier lubricant passage extends radially outward from an inner diameter of the first carrier member and intersects an orifice passage at a radially outward location, and wherein the orifice passage is provided with a traction ring orifice on one end and an idler ring orifice at an opposite end.

8. The CVT of Claim 4, wherein the second carrier member is provided with a second array of carrier lubricant passages, each carrier lubricant passage in fluid communication with the radial lubricant passages of the lubricant sleeve, wherein each carrier lubricant passage extends radially outward from an inner diameter of the second carrier member and intersects an orifice passage at a radially outward location, and wherein the orifice passage is provided with a traction ring orifice on one end and an idler ring orifice at an opposite end.

9. The CVT of Claim 1 , further comprising an idler assembly in contact with each ball at a radially inward location, the idler assembly comprising a first idler ring, a second idler ring, an idler bearing coupled to the first idler ring, and an idler race coupled to the idler bearing and the second idler ring. 0. The CVT of Claim 9, further comprising an idler support tube positioned between the idler race and the shaft.

1 1. The CVT of Claim 10, wherein the idler support tube is coupled to a first radial bearing, the first radial bearing coupled to the lubricant sleeve.