CONTINUOUSLY VARIABLE PLANETARY TRANSMISSION WITH AND WITHOUT TORQUE VECTORING FOR ELECTRIC AND HYBRID ELECTRIC VEHICLES

RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Application No. 62/381 ,675 filed on August 31 , 2016, U.S. Provisional Application No. 62/381 ,682 filed on August 31 , 2016, U.S. Provisional Application No.

62/381 ,693 filed on August 31 , 2016, U.S. Provisional Application No.

62/428, 127 filed on November 30, 2016, U.S. Provisional Application No.

62/434,015 filed on December 14, 2016, and U.S. Provisional Application No. 62/452,714 filed on January 31 , 2017, which are incorporated herein by reference in their entirety.

BACKGROUND

Hybrid vehicles are enjoying increased popularity and acceptance due in large part to the cost of fuel and greenhouse carbon emission government regulations for internal combustion engine vehicles. Such hybrid vehicles include both an internal combustion engine as well as an electric motor to propel the vehicle.

In current electric axle designs for both consuming as well as storing electrical energy, the rotary shaft from a combination electric motor/generator is coupled by a gear train, planetary gear set, to the wheel. As such, the rotary shaft for the electric motor/generator unit rotates in unison with the wheel based on the speed ratio of the gear train.

These fixed ratio designs have many disadvantages, for example the electric motor/generator unit achieves its most efficient operation, both in the sense of generating electricity and also providing additional power to the wheel or the main shaft of the internal combustion engine, only within a relatively narrow range of revolutions per minute of the motor/generator unit. As such, the overall electric or hybrid electric vehicle operates at less than optimal efficiency over a drive cycle. Therefore, there is a need for powertrain configurations that improve the efficiency of electric and hybrid electric vehicles.

SUMMARY

Provided herein is an electric axle powertrain including: a continuously variable electric drivetrain including a motor/generator and a continuously variable transmission; a drive wheel axle operably coupled to the continuously variable electric drivetrain; a first wheel and a second wheel coupled to the drive wheel axle; a differential coupled to the continuously variable electric drivetrain and the drive wheel axle; and a planetary gear set coupled to the drive wheel axle and the continuously variable electric drivetrain, wherein the planetary gear set includes a ring gear, a planet carrier, and a sun gear.

Provided herein is an electric axle powertrain including a continuously variable electric drivetrain having a motor/generator, a first planetary gear set operably coupled to the motor/generator, and a second planetary gear set operably coupled to the motor/generator, wherein the first planetary gear set includes a first ring gear, a first planet carrier, and a first sun gear, and wherein the second planetary gear set includes a second ring gear, a second planet carrier, and a second sun gear; a drive wheel axle operably coupled to the continuously variable electric drivetrain; a differential coupled to the

continuously variable electric drivetrain and the drive wheel axle; and a first wheel and a second wheel coupled to the drive wheel axle.

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 preferred embodiments are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention 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 schematic diagram of an electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to a differential, axle, and wheels of a vehicle.

Figure 5 is a schematic diagram of an electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to a planetary gear set, a differential, axle, and wheels of a vehicle.

Figure 6 is a schematic diagram of another electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to a planetary gear set, a differential, axle, and wheels of a vehicle.

Figure 7 is a schematic diagram of a torque vectoring electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to an axle, two clutches, and wheels of a vehicle.

Figure 8 is a schematic diagram of a torque vectoring electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to an axle through a planetary gear set, two clutches, and wheels of a vehicle.

Figure 9 is a schematic diagram of another torque vectoring electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to an axle through a planetary gear set, two clutches, and wheels of a vehicle. Figure 10 is a schematic diagram of a torque vectoring electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to an axle through two planetary gear sets, two brakes, and wheels of a vehicle.

Figure 11 is a schematic diagram of a torque vectoring electric axle powertrain having a continuously variable electric drivetrain drivingly engaged to an axle through two planetary gear sets, two brakes, and wheels of a vehicle.

Figure 12 is a schematic diagram of a powertrain having a continuously variable electric drivetrain coupled to a set of drive wheels.

Figure 13 is a schematic diagram of a powertrain having a continuously variable electric drivetrain coupled to two planetary gear sets.

Figure 14 is a schematic diagram of another powertrain having a continuously variable electric drivetrain coupled to two planetary gear sets.

Figure 15 is a schematic diagram of a powertrain having a continuously variable electric drivetrain and two clutches.

Figure 16 is a schematic diagram of a powertrain having a continuously variable electric drivetrain, two planetary gear sets, and two brakes.

Figure 17 is a schematic diagram of another powertrain having a continuously variable electric drivetrain, two planetary gear sets, and two brakes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This powertrain relates to electric powertrain configurations and architectures that will be used in hybrid vehicles. The powertrain and/or drivetrain configurations use a ball planetary style continuously variable transmission, such as the VariGlide ^® , in order to couple power sources used in a hybrid vehicle, for example, combustion engines (internal or external), motors, generators, batteries, and gearing. The powertrains disclosed herein are applicable to HEV, EV and Fuel Cell Hybrid systems.

A typical ball planetary variator CVT design, such as that described in United States Patent Publication No. 2008/0121487 and in United States Patent No. 8,469,856, both incorporated herein by reference in their entirety, represents a rolling traction drive system, transmitting forces between the input and output rolling surfaces through shearing of a thin fluid film. The technology is called Continuously Variable Planetary (CVP) due to its analogous operation to a planetary gear system. The system includes an input disc (ring) driven by the power source, an output disc (ring) driving the CVP output, a set of balls fitted between these two discs and a central sun, as illustrated in Figure 1. The balls are able to rotate around their own respective axle by the rotation of two carrier disks at each end of the set of balls axles. The system is also referred to as the Ball-Type Variator.

The preferred embodiments will now be described with reference to the accompanying figures, wherein like numerals refer to like elements throughout. The terminology used in the descriptions below is not to be interpreted in any limited or restrictive manner simply because it is used in conjunction with detailed descriptions of certain specific embodiments. Furthermore, the embodiments include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the inventions described.

Provided herein are configurations of CVTs based on a 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 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, as input (first) 2 and output (second) 3, and an idler (sun) assembly 4 as shown on FIG. 1. Sometimes, the input ring 2 is referred to in illustrations and referred to in text by the label "r1". The output ring is referred to in illustrations and referred to in text by the label "r2". The idler (sun) assembly is referred to in illustrations and referred to in text by the label "s". The balls are mounted on tHtable axles 5, themselves held in a carrier (stator, cage) assembly having a first carrier member 6 operably coupled to a second carrier member 7. Sometimes, the carrier assembly is denoted in illustrations and referred to in text by the label "c". These labels are collectively referred to as nodes ("r1 ", "r2", "s", "c"). 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, as illustrated in FIG. 2. The radial guide slots 8 and the radially offset guide slots 9 are adapted to guide the tillable 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 and second carrier members 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.

The working principle of such a CVP of FIG. 1 is shown on FIG. 3. The

CVP itself works with a traction fluid. The lubricant 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. The 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 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 linked," 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 is capable of taking a variety of forms, which in certain instances will be readily apparent to a person of ordinary skill in the relevant technology.

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 will 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 force which would be available at the interfaces of the contacting components and is the ratio of the maximum available drive torque per contact force. Typically, 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 are capable of operating in both tractive and frictional applications. For example, in the embodiment where a CVT is used for a bicycle application, the CVT operates at times as a friction drive and at other times as a traction drive, depending on the torque and speed conditions present during operation. Embodiments disclosed herein are directed to hybrid vehicle

architectures and/or configurations that incorporate a CVP in place of or in addition to a regular fixed ratio planetary leading to a continuously variable electric axle or hybrid electrical vehicle drivetrain. It should be appreciated that the embodiments disclosed herein are adapted to provide hybrid modes of operation that include, but are not limited to series, parallel, series-parallel, or EV (electric vehicle) modes. In some embodiments, the core element of the power flow is a CVP, such as a VariGlide, which functions as a continuously variable transmission having four nodes (r1 , r2, c, and s). The CVP enables the electric machines (motor/generators, among others) to run at an optimized overall efficiency. It should be noted that hydro-mechanical components such as hydromotors, pumps, accumulators, among others, are capable of being used in place of the electric machines indicated in the figures and

accompanying textual description. Furthermore, it should be noted that embodiments of E-axle architectures disclosed herein could incorporate a supervisory controller that chooses the CVP ratio of highest efficiency and/or power from motor/generator to wheel. Embodiments disclosed herein enable hybrid powertrains that are capable of operating at the best potential overall efficiency point in any mode and also provide torque variability, thereby leading to the optimal combination of powertrain performance and efficiency. It should be understood that electric or hybrid electric vehicles incorporating

embodiments of the hybrid architectures disclosed herein are capable of including a number of other powertrain components, such as, but not limited to, high-voltage battery pack with a battery management system or ultracapacitor, on-board charger, DC-DC converters, a variety of sensors, actuators, and controllers, among others.

For purposes of description, schematics referred to as lever diagrams are used herein. A lever diagram, also known as a lever analogy diagram, is a translational-system representation of rotating parts for a planetary gear system. In certain embodiments, a lever diagram is provided as a visual aid in describing the functions of the transmission. In a lever diagram, a compound planetary gear set is often represented by a single vertical line ("lever"). The input, output, and reaction torques are represented by horizontal forces on the lever. The lever motion, relative to the reaction point, represents direction of rotational velocities. For example, a typical planetary gear set having a ring gear, a planet carrier, and a sun gear can be presented by a vertical line having nodes "R" representing the ring gear, node "S" representing the sun gear, and node "C" representing the planet carrier. It should be appreciated that any mechanical coupling is depicted on a lever diagram as a node or a solid dot. For example, a node represents two components in a drivetrain that are rigidly connected.

Referring to FIGS. 4-6, in some embodiments, an electric axle

powertrain 10, 16, 21 includes a continuously variable electric drivetrain 12 operably coupled to a differential 13. In some embodiments, the differential 13 is a common differential gear set implemented to transmit rotational power. The differential 13 is operably coupled to a wheel drive axle 14 configured to drive a set of vehicle wheels 15 (labeled as "15A" and " 5B" in FIG. 4).

Referring to FIG. 5, in some embodiments, an electric axle powertrain 16 includes the continuously variable electric drivetrain 12 coupled to a planetary gear set 17. The planetary gear set 17 is provided with a ring gear 18, a planet carrier 19, and a sun gear 20. In some embodiments, the continuously variable electric drivetrain 2 is coupled to the sun gear 20. The differential 3 is coupled to the planet carrier 19, and the ring gear 8 is a grounded member. Referring to FIG. 6, in some embodiments, an electric axle powertrain 21 includes the continuously variable electric drivetrain 12 operably coupled to a planetary gear set 22. The planetary gear set 22 is provided with a ring gear 23, a planet carrier 24, and a sun gear 25. In some embodiments, the continuously variable electric drivetrain 12 is operably coupled to the sun gear 25. The differential 13 is operably coupled to the ring gear 23, and the planet carrier 24 is a grounded member. It should be appreciated that the continuously variable electric drivetrain (CVED) 12, as well as references to the CVEDs disclosed herein, is optionally configured to provide an electric motor operably coupled to a continuously variable transmission (CVT) to provide power transmission from the electric axle powertrains described herein. In some embodiments, the CVED 12 incorporates a CVP such as the one described in FIGS. 1-3. In other embodiments, the CVED 12 incorporates a belt-and-pulley, toroidal-type variator, or other known continuously variable device and appropriate gearing.

Turning now to FIGS. 7-9, in some embodiments a torque vectoring electric axle powertrain 26, 29, 34 includes the continuously variable electric drivetrain (CVED) 12 operably coupled to the wheel drive axle 14. The wheel drive axle 14 is operably coupled to a first clutch 27 and a second clutch 28. In some embodiments, the first clutch 27 is configured to selectively engage the drive wheel axle 14 to the first wheel 15A. The second clutch 28 is configured to selectively engage the drive wheel axle 14 to the second wheel 15B. During operation, the first clutch 27 and the second clutch 28 are modulated to vary the torque transmitted to the first wheel 15A and the second wheel 15B, respectively. This modulation is sometimes referred to herein as "torque vectoring". Referring now to FIG. 8, a torque vectoring electric axle powertrain 29 includes the continuously variable drivetrain 12 operably coupled to a planetary gear set 30. The planetary gear set 30 includes a ring gear 31 , a planet carrier 32, and a sun gear 33. In some embodiments, the continuously variable electric drivetrain 12 is operably coupled to the sun gear 33. The drive wheel axle 14 is operably coupled to the planet carrier 32, and the ring gear 31 is a grounded member. Referring now to FIG. 9, in some embodiments, a torque vectoring electric axle powertrain 34 includes the continuously variable electric drivetrain 12 operably coupled to a planetary gear set 35. The planetary gear set 35 is provided with a ring gear 36, a planet carrier 37, and a sun gear 38. In some embodiments, the continuously variable electric drivetrain 12 is operably coupled to the sun gear 38. The ring gear 36 is operably coupled to the drive wheel axle 14, and the planet carrier 37 is a grounded member.

Referring now to FIG. 10, in some embodiments, a torque vectoring electric axle powertrain 39 includes the continuously variable electric drivetrain 12 operably coupled to the drive wheel axle 14. In some embodiments, the drive wheel axle 14 is coupled to a first planetary gear set 40 having a first ring gear 41 , a first planet carrier 42, and a first sun gear 43. The first ring gear 41 is coupled to a first brake 44. In some embodiments, the drive wheel axle 14 is coupled to the first sun gear 43, and the first wheel 15A is coupled to the first planet carrier 42. In some embodiments, the torque vectoring electric axle powertrain 39 includes a second planetary gear set 45 having a second ring gear 46, a second planet carrier 47, and a second sun gear 48. The second ring gear 46 is operably coupled to a second brake 49. The drive wheel axle 14 is coupled to the second sun gear 48, and the second wheel 15B is coupled to the second planet carrier 47. During operation of the torque vectoring electric axle powertrain 39, the first brake 44 and the second brake 45 are modulated to vary the torque transmitted to the first wheel 15A and the second wheel 5B, respectively.

Referring now to FIG. 1 1 , in some embodiments a torque vectoring electric axle powertrain 50 includes the continuously variable electric drivetrain 12 operably coupled to the drive wheel axle 14. The torque vectoring electric axle powertrain 50 includes a first planetary gear set 51 having a first ring gear 52, a first planet carrier 53, and a first sun gear 54. The first ring gear 52 is coupled to the first wheel 15A. The first planet carrier 53 is coupled to a first brake 55. The first sun gear 54 is coupled to the drive wheel axle 14. In some embodiments, the torque vectoring electric axle powertrain 50 includes a second planetary gear set 56 having a first ring gear 57, a second planet carrier 58, and a second sun gear 59. The second ring gear 57 is coupled to the second wheel 15B. The second sun gear 59 is coupled to the drive wheel axle 14. The second planet carrier 58 is coupled to a second brake 60. During operation of the torque vectoring electric axle powertrain 50, the first brake 55 and second brake 60 are modulated to vary the torque to the first wheel 15A and the second wheel 15B, respectively.

Referring now to FIG. 12, in some embodiments, a powertrain 70 includes a continuously variable electric drivetrain (CVED) 71 operably coupled to a set of driven wheels 72. It should be appreciated that embodiments of continuously variable electric drivetrains disclosed herein are configurable to use in place of the continuously variable electric drivetrain 71.

Turning now to FIG. 13, in some embodiments, a powertrain 73 includes the CVED 71 , a first planetary gear set 74 having a first ring gear 75, a first planet carrier 76, and a first sun gear 77. The powertrain 73 includes a second planetary gear set 78 having a second ring gear 79, a second planet carrier 80, and a second sun gear 81. In some embodiments, the CVED 71 is operably coupled to the first sun gear 77 and the second sun gear 81 . The first planet carrier 76 is operably coupled to a first wheel 72A. The second planet carrier 80 is operably coupled to a second wheel 72B. The first ring gear 75 and the second ring gear 79 are grounded members.

Passing now to FIG. 14, in some embodiments, powertrain 82 includes the CVED 71 and a first planetary gear set 83 having a first ring gear 84, a first planet carrier 85, and a first sun gear 86. The powertrain 82 includes a second planetary gear set 87 having a second ring gear 88, a second planet carrier 89, and a second sun gear 90. In some embodiments, the CVED 71 is operably coupled to the first sun gear 86 and the second sun gear 90. The first ring gear 84 is operably coupled to a first wheel 72A. The second ring gear 88 is operably coupled to a second wheel 72B. The first planet carrier 85 and the second planet carrier 89 are grounded members.

Referring now to FIG. 15, in some embodiments, a powertrain 91 includes the CVED 71 , a first clutch 92, and a second clutch 93. The first clutch 92 is operably coupled to the CVED 71 and the first wheel 72A. The second clutch 93 is operably coupled to the CVED 71 and the second wheel 72B.

Turning now to FIG. 16, in some embodiments, a powertrain 94 includes the CVED 71 and a first planetary gear set 95 having a first ring gear 96, a first planet carrier 97, and a first sun gear 98. The first ring gear 96 is operably coupled to a first brake 99. The powertrain 94 includes a second planetary gear set 100 having a second ring gear 101 , a second planet carrier 102, and a second sun gear 103. The second ring gear 101 is operably coupled to a second brake 104. In some embodiments, the CVED 71 is operably coupled to the first sun gear 98 and the second sun gear 103. The first planet carrier 97 is operably coupled to the first wheel 72A. The second planet carrier 102 is operably coupled to the second wheel 72B.

Passing now to FIG. 17, in some embodiments, a powertrain 105 includes the CVED 71 and a first planetary gear set 107 having a first ring gear 107, a first planet carrier 108, and a first sun gear 109. The first planet carrier 108 is operably coupled to a first brake 1 10. The powertrain 105 includes a second planetary gear set 1 1 1 having a second ring gear 1 12, a second planet carrier 1 13, and a second sun gear 1 14. The second planet carrier 1 13 is operably coupled to a second brake 1 15. In some embodiments, the CVED 71 is operably coupled to the first sun gear 109 and the second sun gear 1 14. The first ring gear 107 is operably coupled to the first wheel 72A. The second ring gear 1 12 is operably coupled to the second wheel 72B.

It should be appreciated that when combining electric axle powertrains with continuously variable electric drivetrains (CVED), the planetary rings that are clutched in electric axle powertrains could be grounded and that the grounded rings in continuously variable electric drivetrain (CVED) could be clutched. It should further be noted that the electric axle powertrains disclosed herein are optionally used as primary drive axles, second drive axles, or both.

It should be understood that additional clutches/brakes, step ratios are optionally provided to the hybrid powertrains disclosed herein to obtain varying powerpath characteristics. It should be noted that, in some embodiments, two or more planetary gears and a variator are optionally configured to provide a desired speed ratio range and operating mode to the electric machines. It should be noted that the connections of the electric machines to the

powerpaths disclosed herein are provided for illustrative example and it is within a designer's means to couple the electric machines to other components of the powertrains disclosed herein.

It should be noted that the battery is capable of being not just a high voltage pack such as lithium ion or lead-acid batteries, but also ultracapacitors or other pneumatic/hydraulic systems such as accumulators, or other forms of energy storage systems. The motor/generators described herein are capable of representing hydromotors actuated by variable displacement pumps, electric machines, or any other form of rotary power such as pneumatic motors driven by pneumatic pumps. The electric axle powertrain architectures depicted in the figures and described in text is capable of being extended to create a hydro- mechanical CVT architectures as well for hydraulic hybrid systems.

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.

While 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 are capable of being 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.