Hybrid vehicle transmission having a transfer gear supported on an inverted bearing mount to reduce bearing losses

Abstract

This invention relates to a hybrid vehicle transmission having a transfer gear supported on an inverted bearing mount to reduce bearing losses. An electrically variable transmission includes an output shaft drivably connected to a final drive system of a hybrid vehicle and an input shaft drivably connected to an engine. A transfer gear set is drivably connected to both the output shaft and a first motor. A rolling bearing includes an inner race surrounded by an outer race rigidly attached to the transmission housing. A planetary gear set includes a sun gear drivably connected to a second motor, an ring gear drivably connected to the transfer gear set, and a planetary carrier drivably connected to the input shaft. Located radially inside the transfer gear set is an inverted bearing mount device, which includes an annular outer disc rigidly attached to the ring gear and a cylindrical central hub extending axially from the outer disc and rigidly attached to the inner race of the rolling bearing.

Description

Technical Field

[0001] This disclosure generally relates to powertrain systems for vehicles. More specifically, aspects of this disclosure relate to powertrain systems for hybrid electric vehicles having a dual-motor, single-engine electrically variable transmission that provides power split operation. Background Technology

[0002] Currently manufactured motor vehicles (such as modern automobiles) are initially equipped with a powertrain that operates to propel the vehicle and power its onboard electronics. For example, in automotive applications, the vehicle powertrain is broadly represented by a prime mover that transmits drive torque to the vehicle's final drive system (e.g., differential, axles, steering modules, road wheels, etc.) via an automatic or manual transmission. Automobiles have historically been powered by reciprocating piston internal combustion engine (ICE) components due to their availability, relatively low cost, light weight, and overall efficiency. As some non-limiting examples, such engines include compression ignition (CI) diesel engines, spark ignition (SI) gasoline engines, two-stroke, four-stroke, and six-stroke engines, and Wankel rotary engines. Hybrid vehicles and all-electric vehicles (collectively referred to as "electrically driven vehicles"), on the other hand, utilize alternative power sources to propel the vehicle and thus minimize or eliminate reliance on fossil fuel-based engines for traction power.

[0003] All-electric vehicles (FEVs)—commonly known as "electric cars"—are electric-powered vehicle configurations that completely eliminate the internal combustion engine and associated peripheral components from the powertrain system, instead relying on a rechargeable energy storage system (RESS) and traction motors for propulsion. The engine components, fuel supply system, and exhaust system of ICE-based vehicles are replaced in battery-based FEVs by one or more traction motors, rechargeable battery cells, and battery cooling and charging hardware. In contrast, hybrid electric vehicles (HEVs) use multiple traction power sources to propel the vehicle, most commonly combining an internal combustion engine component with a battery-powered or fuel cell-powered traction motor. Because hybrid electric vehicles can obtain power from sources other than the engine, the HEV engine can be completely or partially shut off when the vehicle is propelled by (multiple) electric motors.

[0004] There are three main types of hybrid powertrain architectures used in modern automobiles: series hybrid, parallel hybrid, and series-parallel (“power-split”) hybrid configurations. A series hybrid powertrain architecture—also known as a range-extended electric vehicle (EREV)—derives all traction power from the electric motor, thus eliminating any drive mechanical connection between the engine and the final drive component. In this case, the powertrain is completely eliminated from the vehicle's powertrain, and the engine functions solely as a regenerative energy source to drive the generator that powers the motor. In contrast, a parallel hybrid architecture has a torque-transfer mechanical connection that drives the engine and motor(s) to the vehicle's road wheels. As the name suggests, a series-parallel hybrid architecture combines features from both parallel and series hybrid powertrains. In gasoline-only, electric-only, and motor-assisted operating modes, the motor and engine operate independently or jointly (in parallel or series) depending on the desired vehicle speed, overall vehicle power demand, and the state of charge (SOC) of the battery(s).

[0005] Power-split HEV powertrains can utilize an electrically variable transmission (EVT) to provide continuously variable speed ratios during both gasoline-only and motor-assisted operation modes. The EVT provides a direct mechanical path between the internal combustion engine and the vehicle's final drive, enabling relatively high transmission efficiency and the application of lower-cost, smaller motor hardware. The EVT can also operate mechanically independent of the final drive engine in various mechanical / electrical separation contributions, enabling high torque continuously variable speed ratios, electrically dominated starting, regenerative braking, and engine-off idling. The EVT can use differential gearing to achieve continuously variable torque and speed ratios between input and output without sending all power through variable elements. For example, an EVT can utilize a planetary gear arrangement to send a portion of its transmitted power through the motor / generator; the remaining power is sent through another parallel path, which is mechanical and direct (i.e., "fixed ratio") or alternatively selectable. Multi-mode EVTs utilize torque-fixing devices such as clutches and brakes to selectively activate differential gearing elements to establish desired forward and reverse speed ratios. Conversely, the single-mode EVT omits the torque clutch device to provide power-split operation mode only for the engine. Summary of the Invention

[0006] The following presents a hybrid electric vehicle (HEV) transmission with a transfer gear supported on an inverted bearing mount to reduce bearing losses, a method for manufacturing such an HEV transmission, a method for using such a transmission, and a hybrid vehicle equipped with such a transmission. In the example, a dual-motor, single-engine electrified continuously variable transmission (eCVT) for a hybrid electric vehicle is proposed. The disclosed concept can be particularly applied to a single-mode power-split HEV eCVT architecture with a planetary gear system having an intermediate “planetary carrier” assembly driven to the engine-side (ICE) input shaft, a central “sun” gear driven to the motor-side (Motor A) input shaft, and an outer “ring” gear driven to the transmission output shaft. With this arrangement, the ring gear can be at the same linkage node as the transfer gear, which is driven to the second motor-side (Motor B) input shaft. In a front-wheel-drive (FWD) powertrain layout, the transfer gear can be part of a countershaft gear train that periodically experiences radial gear reaction loads. The optional parking lock gear can be advantageously combined with the transfer gear and ring gear assembly, and therefore can also withstand radial loading.

[0007] The following discussion concerns the Inverted Bearing Mount (iBM) device, which provides enhanced radial support for the transfer gear, ring gear, and parking lock gear (when present), while reducing bearing losses at the input shaft and ring gear support bearings for All Electric Range (AER), thereby improving fuel economy. The iBM device is encapsulated within the transmission housing and radially inserted between the engine-side input shaft and the meshing ring and transfer gear assemblies. The radially outer end of the iBM device can be press-fitted, sliding-fitted, shrink-fitted, welded, splined, integrally forged, etc. (collectively, “rigidly attached”), while the radially inner end of the iBM device can be rigidly attached to the inner race of a first bearing (e.g., a high-speed deep groove ball bearing). The outer race of the ball bearing can be directly and rigidly attached to the transmission housing on the radially inner side of the transfer gear. In doing so, the iBM device structurally supports the transfer gear and ring gear on the inner race of a roller bearing. The radially inner end of the iBM device can be rigidly attached to a second bearing (e.g., a high-speed cage cylindrical roller bearing) that supports the engine-side input shaft, thereby reducing the relative speed of the bearing during engine start-up operation.

[0008] This disclosure relates to a HEV transmission with a transfer gear supported on a load-transfer bearing mount to reduce bearing losses. In one example, an electrically variable transmission (EVT) assembly for a hybrid vehicle is proposed. The EVT assembly includes a protective transmission housing, which is mounted to the hybrid vehicle, for example, via bushings and bolts, the bolts securing the housing to a transmission mount on the vehicle chassis. Rotatably mounted within the transmission housing are an output shaft driven to the final drive system, an input shaft driven to the crankshaft of the engine, and a transfer gear set driven to the output shaft and a motor shaft of a first motor. Concentric with the input shaft is a first bearing comprising an inner race surrounded by an outer race rigidly attached to the transmission housing. A planetary gear set is located within the transmission housing and includes a sun gear concentric with and driven to the motor shaft of a second motor, an annular gear concentric with and driven to the transfer gear set, and a planetary carrier concentric with and driven to the input shaft. The planetary gear carrier rotatably supports multiple planetary gears that mesh with both the sun gear and the ring gear. An inverted bearing mount assembly, located within the transmission housing and radially inward of the transfer gear set, comprises an annular outer disc and a cylindrical central hub extending axially from the outer disc. The outer disc is rigidly attached to the ring gear (e.g., via splines or as an integral structure), and the cylindrical central hub is rigidly attached to the inner race of the first bearing (e.g., via press fit).

[0009] Additional aspects of this disclosure relate to a motor vehicle equipped with a dual-motor, single-engine HEVEVT transmission having intermeshing transfer gears and ring gear assemblies supported on rigid bearing mounts to reduce bearing losses. As used herein, the terms "vehicle" and "motor vehicle" are used interchangeably and synonymously to include any relevant vehicle platform, such as passenger vehicles, commercial vehicles, industrial vehicles, tracked vehicles, off-road and all-terrain vehicles (ATVs), farm equipment, boats, aircraft, spacecraft, etc. In the example, the hybrid vehicle includes a vehicle body with a cabin, multiple road wheels rotatably mounted to the vehicle body (e.g., via wheel swerving modules coupled to a monocoque or non-monocoque chassis), and other standard original equipment. An internal combustion engine assembly and a pair (first and second) electric traction motors are attached to the vehicle body to propel the HEV. The ICE assembly includes a crankshaft for outputting the engine torque generated by the ICE assembly, and each traction motor includes a corresponding motor shaft for outputting the motor torque generated by that motor.

[0010] Continuing the discussion of the foregoing example, the hybrid vehicle also includes an EVT assembly having a protective transmission housing housed within the vehicle body. A transfer gear set, rotatably connected within the transmission housing, comprises an output shaft driven to the vehicle's final drive system, an input shaft driven to the crankshaft of the ICE, and a motor shaft driven to the output shaft and the first electric motor. A first bearing includes an inner race concentric with the input shaft and surrounded by an outer race rigidly attached to the transmission housing. Located within the transmission housing is a planetary gear set comprising a sun gear concentric with and driven to the motor shaft of the second electric motor, a ring gear concentric with and driven to the transfer gear set, and a planetary carrier concentric with and driven to the input shaft. The planetary carrier rotatably supports a plurality of planetary gears that mesh with both the sun gear and the ring gear. An inverted bearing mount assembly is encapsulated within the transmission housing and radially nested within the transfer gear set. The iBM device includes an annular outer disk with a cylindrical central hub, which is integrally formed with and extends axially from the outer disk. The outer periphery of the outer disk is rigidly attached to an annular gear, and the inner periphery of the central hub is rigidly attached to the inner race of a first bearing.

[0011] This disclosure also relates to system control logic, workflow control protocols, and computer-readable media (CRM) for manufacturing or using any of the vehicles, transmissions, and / or bearing mount devices described herein. In an example, a method for assembling an EVT assembly for a HEV is proposed, the HEV including an engine, a first motor and a second motor, a plurality of road wheels, and a final drive system drivably connected to one or more of the road wheels. This representative method, in any order and in any combination with any of the options and features disclosed above and below, includes: receiving a transmission housing configured for mounting to a hybrid vehicle; rotatably mounting an output shaft within the transmission housing, the output shaft being configured to be drivenly connected to a final drive system; rotatably mounting an input shaft within the transmission housing, the input shaft being configured to be drivenly connected to a crankshaft of an engine; rotatably mounting a transfer gear set within the transmission housing, the transfer gear set being drivenly connected to the output shaft and configured to be drivenly connected to a first motor shaft of a first motor; mounting a first bearing concentric with the input shaft, the first bearing including a first inner race surrounded by a first outer race; rigidly attaching the first outer race to the transmission housing; and positioning a planetary gear set within the transmission housing, the planetary gear set including a sun gear concentric with and configured to be drivenly connected to a second motor shaft of a second motor, an annular gear concentric with and drivenly connected to the transfer gear set, and a planetary gear carrier concentric with and drivenly connected to the input shaft. A planetary gear carrier rotatably supports a plurality of planetary gears that mesh with a sun gear and a ring gear; the iBM device is positioned within a transmission housing radially inward of the transfer gear set, the iBM device including an annular outer disk and a cylindrical central hub extending axially from the outer disk; the outer disk is rigidly attached to the ring gear; and the cylindrical central hub is rigidly attached to a first inner race of a first bearing.

[0012] For any of the disclosed powertrains, vehicles, and methods, the iBM device, including the outer disk and the center hub, can be integrally formed as a single-piece structure from a rigid metallic material (e.g., forged steel). Alternatively, the outer diameter (OD) surface of the outer disk is rigidly attached (e.g., with a shrink fit) to the inner diameter (ID) surface of the ring gear, while the OD surface of the center hub is rigidly attached (e.g., with a press fit) to the ID surface of the first bearing. The iBM device may optionally include a spacer ring that extends axially from the outer disk and surrounds the center hub. This spacer ring can be integrally formed with the outer disk and the center hub, pressing against the inner race of the first bearing, and thereby axially spaced the first bearing from the outer disk.

[0013] For any of the disclosed powertrains, vehicles, and methods, the second bearing can be rotatably mounted on the input shaft; the center hub of the iBM device can be concentric with and rigidly attached to the outer race of the second bearing. In doing so, the center hub of the iBM device is sandwiched between the first and second bearings. The iBM device may optionally include a retaining ring that extends radially inward from the center hub and presses against the outer race of the second bearing, thereby axially retaining the second bearing within the center hub. Like a spacer ring, the retaining ring can be integrally formed with the outer disk and center hub of the iBM device. In this case, the OD surface of the center hub can be rigidly attached (e.g., press-fitted) to the ID surface of the first bearing, and the ID surface of the center hub can be rigidly attached (e.g., press-fitted) to the OD surface of the second bearing.

[0014] For any of the disclosed powertrains, vehicles, and methods, the transmission housing may include a main housing having a front cover mounted to the main housing and receiving an input shaft therethrough. An annular gear recess is located on the front cover, for example, integrally formed with and extending inwardly from the inner surface of the front cover. The gear recess is rigidly attached to the outer race of a first bearing, such that the first bearing is nested within the gear recess. Optionally, an annular bearing gasket may be disposed within the gear recess, sandwiched between the front cover and the outer race of the first bearing, thereby axially spaced the first bearing from the front cover. In this case, a center hub may be nested within the gear recess, radially inserted between the first bearing and the input shaft.

[0015] For any of the disclosed powertrains, vehicles, and methods, the outer disk of the iBM device can be axially inserted between the planetary gear carrier and the first bearing and radially inserted between the ring gear and the input shaft. Alternatively, the iBM device can have an L-shaped axial section, wherein a cylindrical central hub extends orthogonally from the radially inner periphery of the outer ring disk. Alternatively, the sun gear can be integrally formed with the end portion of the motor shaft of the first motor, the planetary gear carrier can be splined to the input shaft, and the external teeth of the ring gear can mesh with the internal teeth of the transfer gear.

[0016] The present invention provides the following technical solutions.

[0017] Technical Solution 1. An electrically variable transmission (EVT) assembly for a hybrid vehicle, the hybrid vehicle including an engine, a first motor and a second motor, a plurality of road wheels and a final drive system drivably connected to one or more of the road wheels, the EVT assembly comprising:

[0018] A transmission housing configured for mounting to the hybrid vehicle;

[0019] An output shaft that is rotatable within the transmission housing and configured to be drivenly connected to the final drive system;

[0020] An input shaft, which is rotatable within the transmission housing and configured to be drivenly connected to the crankshaft of the engine;

[0021] The transfer gear set is rotatable within the transmission housing, drivably connected to the output shaft, and configured to drivably connect to the first motor shaft of the first motor;

[0022] A first bearing, which is concentric with the input shaft, and includes a first inner race surrounded by a first outer race rigidly attached to the transmission housing;

[0023] A planetary gear set, located inside the transmission housing, includes a sun gear concentric with and drivably connected to the second motor shaft of the second motor; a ring gear concentric with and drivably connected to the transfer gear set; and a planetary carrier concentric with and drivably connected to the input shaft, on which a plurality of planetary gears meshing with the sun gear and the ring gear are rotatably supported; and

[0024] An inverted bearing mount (iBM) device is located radially inside the transfer gear set within the transmission housing. The IBM device includes an annular outer disk rigidly attached to the ring gear and a cylindrical central hub extending axially from the outer disk and rigidly attached to the first inner race of the first bearing.

[0025] Technical Solution 2. The EVT assembly according to Technical Solution 1, wherein the iBM device, including the outer disk and the center hub, is integrally formed into a single-piece structure from a rigid metal material.

[0026] Technical Solution 3. The EVT assembly according to Technical Solution 1, wherein the outer diameter (OD) disk surface of the outer disk is rigidly attached to the inner diameter (ID) gear surface of the ring gear, and the OD hub surface of the center hub is rigidly attached to the ID bearing surface of the first bearing.

[0027] Technical Solution 4. The EVT assembly according to Technical Solution 1, wherein the iBM device further includes a spacer ring that extends axially from the outer disc and surrounds the central hub, the spacer ring pressing against the first inner race and thereby spaced the first bearing from the outer disc.

[0028] Technical Solution 5. The EVT assembly according to Technical Solution 1 further includes a second bearing rotatably mounted on the input shaft, wherein the central hub is concentric with and rigidly attached to the second outer race of the second bearing.

[0029] Technical Solution 6. The EVT assembly according to Technical Solution 5, wherein the iBM device further includes a retaining ring extending radially inward from the central hub, the retaining ring pressing against the second outer race and thereby axially retaining the second bearing inside the central hub.

[0030] Technical Solution 7. The EVT assembly according to Technical Solution 5, wherein the outer diameter (OD) hub surface of the center hub is rigidly attached to the inner diameter (ID) bearing surface of the first bearing, and the ID hub surface of the center hub is rigidly attached to the OD bearing surface of the second bearing.

[0031] Technical Solution 8. The EVT assembly according to Technical Solution 1, wherein the transmission housing includes a main housing, a front cover mounted on the main housing and receiving the input shaft therethrough, and an annular gear recess, the annular gear recess being located on the inner surface of the front cover and rigidly attached to the first outer race, such that the first bearing is nested inside the gear recess.

[0032] Technical Solution 9. The EVT assembly according to Technical Solution 8 further includes an annular bearing washer, the annular bearing washer being disposed inside the gear recess and sandwiched between the front cover and the first outer race of the first bearing.

[0033] Technical Solution 10. The EVT assembly according to Technical Solution 8, wherein the center hub is nested inside the gear recess radially inserted between the first bearing and the input shaft.

[0034] Technical Solution 11. The EVT assembly according to Technical Solution 1, wherein the outer disk of the iBM device is axially inserted between the planetary gear carrier and the first bearing and radially inserted between the ring gear and the input shaft.

[0035] Technical Solution 12. The EVT assembly according to Technical Solution 1, wherein the iBM device has an L-shaped axial cross section, wherein the central hub extends orthogonally from the radially inner end of the outer disk.

[0036] Technical Solution 13. A hybrid electric vehicle, comprising:

[0037] The vehicle itself;

[0038] Multiple road wheels are attached to the vehicle body;

[0039] An internal combustion engine (ICE) assembly, which is attached to the vehicle body and includes a crankshaft configured to output engine torque generated by the ICE assembly;

[0040] A first electric motor and a second electric motor are attached to the vehicle body and include a first motor shaft and a second motor shaft, the first motor shaft and the second motor shaft being respectively configured to output motor torque generated by the first electric motor and the second electric motor.

[0041] The final drive system, which is droopily connected to one or more of the road wheels; and

[0042] An electrically variable transmission (EVT) assembly, comprising:

[0043] A transmission housing, which is installed inside the vehicle body;

[0044] An output shaft, which is rotatable within the transmission housing and driven to be connected to the final drive system;

[0045] The input shaft, which is rotatably and driveably connected within the transmission housing, is...

[0046] The crankshaft of the ICE assembly;

[0047] The transfer gear set is rotatable within the transmission housing, is drivably connected to the output shaft, and is drivably connected to the first motor shaft of the first electric motor;

[0048] A first bearing, which is concentric with the input shaft, and includes a first inner race surrounded by a first outer race rigidly attached to the transmission housing;

[0049] A planetary gear set, located inside the transmission housing, includes a sun gear concentrically and driveably connected to the second motor shaft of the second electric motor; a ring gear concentrically and driveably connected to the transfer gear set; and a planetary gear carrier concentrically and driveably connected to the input shaft, wherein the planetary gear carrier rotatably supports a plurality of planetary gears meshing with the sun gear and the ring gear; and

[0050] An inverted bearing mount (iBM) device is located radially inside the transfer gear set within the transmission housing. The iBM device includes an annular outer disc and a cylindrical central hub integrally formed with and extending axially from the outer disc. The outer disc is rigidly attached to the annular gear, and the central hub is rigidly attached to the first inner race of the first bearing.

[0051] Technical Solution 14. A method for assembling an electrically variable transmission assembly for a hybrid vehicle, the hybrid vehicle including an engine, a first motor and a second motor, a plurality of road wheels, and a final drive system drometically connected to one or more of the road wheels, the method comprising:

[0052] A transmission housing is received, the transmission housing being configured for installation into the hybrid vehicle;

[0053] The output shaft is rotatably mounted within the transmission housing, and the output shaft is configured to be driven to the final drive system;

[0054] The input shaft is rotatably mounted within the transmission housing, and the input shaft is configured to be drivenly connected to the crankshaft of the engine;

[0055] The transfer gear set is rotatably mounted in the transmission housing, the transfer gear set is driven to the output shaft and configured to be driven to the first motor shaft of the first motor;

[0056] A first bearing concentric with the input shaft is installed, the first bearing including a first inner race surrounded by a first outer race;

[0057] The first outer race is rigidly attached to the transmission housing;

[0058] The planetary gear set is positioned inside the transmission housing. The planetary gear set includes a sun gear that is concentric with the second motor shaft of the second motor and configured to be driven to the second motor shaft; a ring gear that is concentric with the sun gear and driven to the transfer gear set; and a planetary gear carrier that is concentric with the input shaft and driven to the input shaft. The planetary gear carrier rotatably supports a plurality of planetary gears that mesh with the sun gear and the ring gear.

[0059] The inverted bearing mount (iBM) device is positioned inside the transmission housing on the radially inner side of the transfer gear set, the iBM device including an annular outer disk and a cylindrical central hub extending axially from the outer disk;

[0060] The outer disk is rigidly attached to the ring gear; and

[0061] The cylindrical central hub is rigidly attached to the first inner race of the first bearing.

[0062] Technical Solution 15. The method according to Technical Solution 14 further includes integrally forming the iBM device, including the outer disk and the central hub, into a single-piece structure using a rigid metal material.

[0063] Technical Solution 16. The method according to Technical Solution 14, wherein the outer diameter (OD) disk surface of the outer disk is rigidly attached to the inner diameter (ID) gear surface of the ring gear, and the OD hub surface of the central hub is rigidly attached to the ID bearing surface of the first bearing.

[0064] Technical Solution 17. The method according to Technical Solution 14, wherein the iBM device further includes a spacer ring extending axially from the outer disk and surrounding the central hub, the spacer ring pressing against the first inner race and thereby spaced the first bearing from the outer disk.

[0065] Technical solution 18. The method according to technical solution 14 further includes:

[0066] The second bearing is rotatably mounted onto the input shaft; and

[0067] The center hub is rigidly attached to the second outer race of the second bearing, such that the center hub is concentric with the second bearing.

[0068] Technical Solution 19. The method according to Technical Solution 18, wherein the iBM device further includes a retaining ring extending radially inward from the central hub, the retaining ring pressing against the second outer race and thereby axially retaining the second bearing inside the central hub.

[0069] Technical Solution 20. The method according to Technical Solution 14, wherein the transmission housing includes a main housing, a front cover mounted on the main housing and receiving the input shaft therethrough, and an annular gear recess, the annular gear recess being located on the inner surface of the front cover and rigidly attached to the first outer race, such that the first bearing is nested inside the gear recess.

[0070] The foregoing summary does not represent every embodiment or aspect of this disclosure. Rather, it merely provides a summary of some novel concepts and features set forth herein. The foregoing features and advantages, as well as other features and accompanying advantages, will become apparent from the following detailed description of illustrative examples and representative modes for carrying out this disclosure when taken in conjunction with the accompanying drawings and appended claims. Furthermore, this disclosure expressly includes any and all combinations and sub-combinations of the elements and features presented above and below. Attached Figure Description

[0071] Figure 1 This is a schematic diagram of a representative dual-motor, single-engine hybrid electric vehicle (HEV) powertrain architecture with a power-split electric variable transmission (EVT), which enables the implementation of aspects of this disclosure.

[0072] Figure 2 This is an enlarged cross-sectional side view of a portion of a representative power shunt HEVEVT according to an aspect of this disclosure, the representative power shunt HEVEVT having a transfer gear supported on an inverted bearing mount to reduce bearing losses.

[0073] This disclosure allows for various modifications and alternatives, and some representative embodiments of this disclosure are illustrated by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that the novel aspects of this disclosure are not limited to the specific forms illustrated in the drawings listed above. Rather, this disclosure covers all modifications, equivalents, combinations, arrangements, groupings, and alternatives that fall within the scope of this disclosure as defined, for example, by the appended claims. Detailed Implementation

[0074] This disclosure allows for numerous different forms of embodiments. Representative embodiments of this disclosure are shown in the accompanying drawings and will be described in detail herein, while it is understood that these embodiments are provided as examples of the principles disclosed and not as limitations on the broad aspects of this disclosure. Therefore, elements and limitations described, for example in the abstract, introduction, summary of the invention, description of the drawings, and detailed description but not expressly set forth in the claims should not be incorporated into the claims, individually or collectively, by implication, inference, or otherwise. Furthermore, the expressions “first,” “second,” “third,” etc., in the specification or claims are not, in themselves, intended to establish a sequence or numerical limitation; unless specifically stated otherwise, these names may be used to facilitate reference to similar features in the specification and drawings and to distinguish between similar elements in the claims.

[0075] For the purposes of this disclosure, unless specifically denied: the singular includes the plural, and vice versa (e.g., the indefinite articles “a” and “one” should be interpreted substantially as meaning “one or more”); the words “and” and “or” should be conjunction and disjunction; the words “any” and “all” should both mean “any and all”; and the words “contains,” “includes,” “includes,” “has,” etc., should each mean “including but not limited to.” Furthermore, approximate words such as “about,” “almost,” “substantially,” “generally,” “approximately,” etc., may each be used herein to mean, for example, “at, near, or almost at,” or “within 0-5% of,” or “within acceptable manufacturing tolerances,” or any logical combination thereof. Finally, directional adjectives and adverbs (such as front, back, inside, outside, right, left, vertical, horizontal, up, down, front, rear, left, right, etc.) may be relative to a motor vehicle, such as the forward direction of travel of the motor vehicle when it is operatively oriented on a horizontal drive surface.

[0076] Referring now to the accompanying drawings, where similar reference numerals throughout several views denote similar features, in Figure 1 A representative motor vehicle, generally designated 10, is illustrated herein and, for the purposes of discussion, is depicted as a hybrid electric vehicle. The illustrated vehicle 10—also referred to herein simply as a “motor vehicle” or “vehicle”—is merely an exemplary application that can practice aspects of this disclosure. Similarly, incorporating the concepts of the invention into the illustrated power-split HEV EVT architecture should be understood as a non-limiting implementation of the disclosed features. Therefore, it will be understood that aspects and features of this disclosure can be incorporated into other EVT configurations, implemented by other powertrain layouts, and incorporated into any logically related type of motor vehicle. Furthermore, only representative motor vehicles and selected components of the vehicle transmission are shown and described in detail herein. However, the vehicles and transmissions discussed below may include numerous additional and alternative features and other available peripheral components for performing the various methods and functions of this disclosure.

[0077] Figure 1 The vehicle 10 includes a hybrid electric vehicle (HEV) powertrain 11, designed to provide vehicle start-up and propulsion, operate across a full speed range between low and high road speeds, and power onboard vehicle electronics. According to a more specific, non-limiting example, the powertrain 11 may be a range-extended electric vehicle (EREV) powertrain having a variable displacement 2.5-liter (L) four-cylinder internal combustion engine assembly 12 and two 120 kW multiphase brushless permanent magnet (PM) motor / generator units (MGUs) 14 and 16, which are mounted to a multi-speed, power-split electric variable transmission (EVT) 18. As shown in the accompanying drawings, the “electric variable transmission” includes a transmission planetary gear system operatively connected to each of the engine 12, the first motor / generator unit (MGU) 14, and the second MGU 16. Directing the respective torques of engine 12 and the two motor / generator units 14, 16 (interchangeably referred to as "traction motors") to different components of the planetary gear system allows one power source to assist or balance the operation of the other two power sources. Therefore, the combination of engine 12 and multiple motor / generator units 14, 16 operatively connected to EVT 18 allows for independent control and selection of the speed and torque of the engine and motor / generators to more efficiently power the main vehicle 10.

[0078] Vehicle 10 is equipped with a vehicle battery system 15, which may include, for example, multiple battery cells arranged as battery modules, stacked into multiple traction battery packs 21A and 21B. These battery cells may utilize suitable battery technologies, including, for example, lead-acid, nickel metal hydride (NiMH), lithium-ion (“Li-Ion”), lithium-ion polymer, zinc-air, lithium-air, nickel-cadmium (NiCad), valve-regulated lead-acid (“VRLA”) including an absorber glass pad (“AGM”), nickel-zinc (NiZn), molten salt (e.g., Na-NiCl2 battery), or combinations thereof. Each battery pack or each battery cell may be associated with one or more sensors to measure one or more battery characteristics (e.g., voltage, current, temperature, SOC, capacity, etc.) associated with each battery pack / cell. Vehicle battery system 15 is operatively connected to a first motor / generator unit 14 and a second motor / generator unit 16 to transmit current to and receive current from these MDUs. The resident vehicle controller 23 is communicatively connected to the engine 12, traction motors 14 and 16, vehicle battery system 15, and EVT 18 to control their operation. Controllers, control modules, modules, control units, processors, and their arrangements can be defined as one or more of the following: logic circuits, (multiple) application-specific integrated circuits (ASICs), (multiple) electronic circuits, (multiple) central processing units (e.g., (multiple) microprocessors) and associated memory and storage devices (e.g., read-only, programmable read-only, random access, hard disk drives, tangible, etc.), (multiple) combinational logic circuits, (multiple) input / output circuits, and devices, whether resident, remote, or a combination of both.

[0079] The vehicle controller 23 may be integrated circuit (IC) hardware programmed to execute one or more software or firmware programs or routines (e.g., using appropriate signal conditioning and buffering circuitry systems and other components) to provide the described functionality. Software, firmware, programs, instructions, routines, code, algorithms, and similar terms may be defined to refer to a controller-executable instruction set, including calibration and lookup tables. The controller may be designed with a set of control routines executed to provide one or more desired functions. These control routines, such as those executed by a central processing unit, are operable to monitor inputs from sensing devices and other networked control modules, and to execute control and diagnostic routines to control the operation of devices and actuators. The routines may execute in real-time, continuously, systematically, sporadically, and / or at regular intervals during ongoing vehicle use, such as every 100 microseconds, 3.125, 6.25, 12.5, 25, and 100 milliseconds. Alternatively, the routines may execute in response to the occurrence of an event during operation of the vehicle 10.

[0080] Figure 1 The EVT 18 selectively operates as a continuously variable powertrain, comprising a planetary gear set (PGS) 22 and a gear train 26, and helps define the input split hybrid powertrain 11 architecture. In this respect, the PGS 22 includes a ring gear 34, a planetary gear carrier 36, and a sun gear 38. Multiple planetary gears 35 mesh with the ring gear 34 and are mounted on the planetary gear carrier 36, while the sun gear 38 meshes with the planetary gears(s)35 and is concentrically aligned with the ring gear 34, such that the ring gear 34, planetary gears 35, and planetary gear carrier 36 rotate about the axis of rotation of the sun gear 38. In the illustrated example, the ring gear 34 of the PGS 22 includes radially inner teeth that mesh with the planetary gears 35 located on a first portion of the ring gear 34 and radially outer teeth that engage with the split gear train 26 located on a second portion of the ring gear 34.

[0081] like Figure 1 As shown, engine 12 and first motor / generator unit 14, or at least their respective torque transmission output shafts, can be configured to rotate on a common first axis of rotation A1. Conversely, second motor / generator unit 16, or at least its torque transmission output shaft, can be configured to rotate on a second axis of rotation A2. According to the illustrated example, the first axis A1 is substantially parallel to and offset from the second axis A2. Figure 1 The gear train 26 is configured to operatively connect the second motor / generator unit 16 to the PGS22 at the corresponding engagement point.

[0082] Engine 12, first MGU 14, and second MGU 16 are operatively connected to EVT 18 via an input member arrangement that transmits torque between the traction power source and PGS 22. As a non-limiting example, the input member arrangement includes: an engine output shaft of engine 12, which serves as an engine input / output member 46; a rotor of first MGU 14, which serves as a first motor input / output member 48; and a rotor of second MGU 16, which serves as a second motor input / output member 56. Engine input / output member 46 provides engine torque to EVT 18, while motor input / output members 48, 56 provide torque from their respective motor / generator units 14, 16 to EVT 18. A damper assembly 65 operatively connected to the input / output shaft 46 of engine 12 is configured to absorb torsional vibrations generated by engine 12 before they can be transmitted to PGS 22 of EVT 18.

[0083] The gear train 26 includes a motor B pinion (MBP) 28 configured to rotate together with the second motor input / output member 56, and the MBP 28 meshes with a transfer gear 30. The transfer gear 30 is supported for rotation on the final drive pinion (FDP) 32. Figure 2 As shown, the transfer gear 30 includes teeth 31 that mesh with radially external teeth 37 on the ring gear 34.

[0084] EVT 18 also includes a final drive ring (FDR) 59, shown in dashed lines as directly mechanically engaged with FDP 32 for illustrative purposes. To propel vehicle 10, FDP 32 and FDR 59 transmit torque to the final drive system 13, which is represented herein by differential 17, drive wheels 19, and axle 25. Regenerative braking is achieved by transmitting torque from the final drive system 13 to MGUs 14 and 16 when MGUs 14 and 16 are operating in generator mode.

[0085] exist Figure 1 In the example depicted, engine 12 can be an available or later-developed engine, such as a two-stroke or four-stroke compression-ignition diesel engine or a four-stroke spark-ignition gasoline or flexible fuel engine, which is easily adapted to typically provide its available power output at a few revolutions per minute (RPM). Although in Figure 1 Although not explicitly described, it should be understood that the final drive system 13 can adopt available configurations, including front-wheel drive (FWD) layout, rear-wheel drive (RWD) layout, four-wheel drive (4WD) layout, all-wheel drive (AWD) layout, etc.

[0086] During the operation of a vehicle transmission, the torque-carrying capacity of the internal bearings may degrade over their service life due to the inherently high friction and high speed characteristics of the operation. This high friction and high speed can lead to an increase in heat loss energy, also known as "bearing loss." To mitigate such bearing loss, the disclosed hybrid vehicle transmission includes a bearing mount that structurally supports a meshing ring gear and a transfer gear assembly on two concentric rolling bearings, one of which is supported on the transmission housing and the other on the engine-side input shaft. For example, the bearing mount (also known as an "inverted bearing mount" or "iBM") can be encapsulated within the transmission housing and coupled to a support (ball) bearing that is mounted to the transmission housing and supports the transfer gear via its inner race. The iBM may have a generally L-shaped cross-section and may be radially inwardly positioned relative to the surrounding transfer gear. Furthermore, the iBM feature can be integral with the ring gear (e.g., conventional forging) or can be a separate component rigidly attached to the ring gear (e.g., press fit, sliding fit, or contraction fit, welding, spline connection, fastening, adhesion, or a combination thereof). The iBM feature can have two diametrical surfaces trimmed to mate with two bearings: (a) an outer diameter (OD) surface that mates with the inner race of a support bearing that supports the iBM and thereby supports the transfer gear set; and (b) an inner diameter (ID) surface that mates with a shaft (cylindrical roller) bearing that supports the input shaft of the transmission.

[0087] By accommodating the shaft bearing supporting the input shaft of the transmission, the bearing mount reduces the relative speed of the bearing and thus reduces any accompanying bearing losses. The trimmed ID surface of the generally L-shaped iBM feature allows the high-speed cylindrical roller bearing to be mounted into the flange cavity, for example, by press fit. By mounting the input shaft support bearing in this position, the relative speed between the bearing races can be reduced for most of the time during engine-on operation, compared to, for example, in the case of the transmission, because when the engine is on and the vehicle is moving forward, the input and output components of the transmission (i.e., via the transfer gears of the iBM feature) can rotate in the same direction.

[0088] In addition to reducing bearing losses in the shaft bearings and structurally supporting the meshing ring gear and transfer gear, the bearing mount can also be used to increase the moment of inertia of the radially inward sections of the ring gear and transfer gear, while simultaneously increasing the stiffness of the transfer gear. The moment of inertia of the rectangular section of the gear about the neutral axis is a function of the product of the dimensions of the base and the cube of its height. By structurally mating with the ring gear at its point of radial alignment with the transfer gear, the iBM extension feature increases the relative height h of the transfer gear; the iBM and the transfer gear are interconnected, making the two components structurally a single unit. This results in a measurable increase in the stiffness of the combined component, such that the deflection under loads imposed by gear meshing (including the transfer gear meshing and pinion meshing associated with the planetary gear set, support bearings, and parking gear) is lower than their deflection without the bearing mount feature.

[0089] Figure 2 A cross-sectional side view of a representative power-split HEV EVT 118 is presented, showcasing reduced bearing losses at the engine shaft support bearings, increased stiffness of the transfer gear set, and improved structural support at the meshing ring gear and transfer gear assemblies. Those skilled in the art will understand that only a portion of the HEV EVT 118 (the torque input section above the central axis of rotation AA) is... Figure 2 As can be seen in the diagram; the section directly below the rotation axis AA, although not visible, could be a mirror image of the shown portion. Furthermore, although it presents itself as a single-mode power-split eCVT, it can be envisioned that... Figure 2 The aspects and features of HEVEVT118 can be combined individually and collectively. Figure 1 In the hybrid transmission 18, and vice versa. As a non-restrictive overlap point, Figure 2 The HEV EVT 118 includes a protective transmission housing 133 that supports the working hardware of the vehicle's powertrain and is mounted to the vehicle body, for example, via brackets, bushings, and bolts that secure the housing to the transmission mount on the vehicle chassis. The transmission housing 133... Figure 2 The main body is represented by a bowl-shaped main housing (central support) 135, which has a complementary front cover (bell-shaped housing casting) 137, which is mounted, for example, to the engine-facing opening end of the main housing 135 via hexagonal head bolts.

[0090] picture Figure 1 Like the HEV EVT 18, Figure 2 The HEV transmission 118 includes an output shaft (e.g., Figure 1 The output shaft of the transmission is driven to the vehicle's drivetrain (e.g., Figure 1The final drive system 13) transmits traction torque to the vehicle's road wheels (e.g., drive wheels 19). An engine-side (ICE) input shaft 146 is also rotatably mounted inside the transmission housing 133. This input shaft 146 passes through the front cover 137 and is driven to the engine output components (e.g., [unclear text - likely referring to a specific component or structure]) via a coaxially aligned torsional damper assembly 164 and a crankshaft hub (not visible). Figure 1 The engine crankshaft). The motor-side (motor A) input shaft 148 of the "small" MGU passes through the central support section of the main housing 135 to drively connect the MGU to the EVT 118, thereby enabling the back-and-forth exchange of rotational power. According to the illustrated example, the ICE input shaft 146 passes through the motor input shaft 148 and rotates inside the motor input shaft 148. Radially offset from and parallel to the two concentric input shafts 146, 148 is a transfer gear set 144, which drively connects (e.g., via spline engagement) to the motor-side (motor B) input shaft of the "large" second MGU (e.g., the engine crankshaft). Figure 1 The motor stator shaft is used to drive the MGU to the EVT 118, thereby enabling the back-and-forth exchange of rotational power.

[0091] Multiple radial support bearings are Figure 2 The various torque transmission shafts of the EVT 118 provide rotational support. As an example, in... Figure 2 Four radial rolling bearings are visible: (1) an engine-side high-speed deep groove ball bearing (first) 150, (2) an engine-side high-speed cage cylindrical roller bearing (second) 152, (3) a motor-side high-speed deep groove ball bearing (third) 154, and (4) an engine-side high-speed cage cylindrical roller bearing (fourth) 156. The first bearing 150 and the second bearing 152 are concentric with each other and with the ICE input shaft 146, while the third bearing 154 and the fourth bearing 156 are concentric with each other and with the ICE input shaft 146 and the motor input shaft 148. The third bearing 154 rotatably mounts the motor-side axial end of the ring gear 128 to the OD surface of the inwardly extending lip of the main housing 135. In contrast, the fourth bearing 156 rotatably mounts the engine-side axial end of the motor input shaft 148 to the ID surface of the same inwardly extending lip of the main housing 135. It should be understood that, without departing from the intended scope of this disclosure, each of the illustrated bearing assemblies may employ other suitable bearing configurations, including needle roller bearings, tapered roller bearings, thrust ball bearings, etc.

[0092] Continue to refer to Figure 2The first bearing 150 is a ball bearing, comprising a grooved annular inner race 151, a grooved annular outer race 153 surrounding and coaxial with the inner race 151, and a series of circumferentially spaced bearing balls 155 slidably inserted between the inner race 151 and the outer race 153. The outer race 153 of the first bearing 150 is rigidly attached (e.g., press-fitted) to the front cover 137 of the transmission housing 133. In contrast, the second bearing 152 is a roller bearing, comprising an annular outer race 157, a series of circumferentially spaced cylindrical rollers 159 slidably inserted between the outer race 157 and the ICE input shaft 146, and a slotted roller cage 161 maintaining the axial alignment and circumferential spacing of the rollers 159. The axial end of the second bearing 152 is positioned against a thrust bearing 158.

[0093] Located inside the main housing 135 of the transmission housing is a planetary gear set 122, which drives the three prime movers of the HEV to connect to each other and to the HEV's final drive system. Similar to... Figure 1 PGS22, Figure 2 The planetary gear set 122 comprises a ring gear assembly 128, a planetary gear carrier assembly 130, and a sun gear assembly 132. Circumferentially spaced planetary gears 129 are rotatably mounted on the planetary gear carrier 130 and mesh with both the ring gear 128 and the sun gear 132. With this arrangement, the sun gear 132 is surrounded by and concentrically aligned with the ring gear 128, causing both to rotate together with the planetary gear carrier 130 about a common axis AA. Furthermore, the sun gear 132 is concentrically and drivably connected to the motor input shaft 148 (e.g., integrally formed to the distal end of the shaft), and the ring gear 128 is drivably connected to the transfer gear set 144 (e.g., via meshing OD ring gear teeth 121 and ID transfer gear teeth 123). The intermediate planetary gear carrier assembly 130 is drivably connected to the ICE input shaft 146 (e.g., via spline engagement).

[0094] Reduced bearing losses and increased transfer gear stiffness are provided by the inverted bearing mount (iBM) device 160, which is encapsulated inside the transmission housing 133, located radially inward of the transfer gear set 144, and nested within it. Figure 2The bearing mounting device 160 is located inside the central annular cavity of the ring gear 128. The bearing mounting device 160 may have a cap-like shape, consisting of an annular outer disk 162 and a cylindrical central hub 166 extending axially from the outer disk 162. The outer disk 162 extends radially inward from the ring gear 128 and surrounds the input shaft 146. Conversely, the central hub 166 extends axially along and surrounds the input shaft 146. For ease of manufacture and installation, it may be desirable for the iBM device 160, comprising the outer disk 162 and the central hub 166, to be integrally formed as a single piece of rigid metallic material (e.g., forged steel).

[0095] Figure 2 The iBM device 160 structurally connects a ring gear 128 to a first bearing 150 and a second bearing 152, such that the ring gear 128 and the transfer gear set 144 are supported on the two bearings 150, 152 and the transmission housing 133. Specifically, the OD surface on the outer periphery of the outer disc 162 is rigidly attached (e.g., splined) to the ID surface on the inner periphery of the ring gear 128. The OD surface on the outer periphery of the center hub 166 is rigidly attached (e.g., interference fit) to the ID surface on the inner periphery of the inner race 151 of the first bearing. The iBM device 160 may be fabricated with an optional spacer ring 163 that extends axially from the outer disc 162 and surrounds the center hub 166. This toroidal spacer ring 163 may be integrally formed with both the outer disc 162 and the center hub 166, pressing against the inner race 151 of the first bearing 150. In this way, the spacer ring 163 axially separates the first bearing 150 from the outer disk 162, so that neither the outer race 153 nor the bearing ball 155 has direct physical contact with the bearing mount 160.

[0096] To rotatably mount the input shaft 146 onto the transmission housing 133, the center hub 166 of the iBM device 160 can be concentrically and rigidly attached to the outer race 157 of the second bearing 152. In doing so, the center hub 166 of the iBM device is sandwiched between the first bearing 150 and the second bearing 152. An optional retaining ring 165 can be integrally formed with the center hub 166 and extend radially inward from the center hub 166. This annular retaining ring 165 presses against the outer race 157 of the second bearing, thereby axially retaining the second bearing 152 within the center hub 166. In this configuration, the OD surface of the center hub 166 can be rigidly attached (e.g., press-fit or sliding fit) to the ID surface of the inner race 151 of the first bearing, and the ID surface of the center hub 166 can be rigidly attached (e.g., press-fit or sliding fit) to the OD surface of the outer race 157 of the second bearing.

[0097] An annular gear recess 139 may be disposed within the transmission housing 133, for example, integrally formed with and facing inward from the inner surface of the front cover 137, to structurally mate the transmission housing 133 with the bearing mount 160. According to the illustrated example, the gear recess 139 includes an annular outer wall rigidly attached (e.g., via press fit) to the outer race 153 of the first bearing, such that the first bearing 150 is nested within the gear recess 139. An optional annular bearing gasket 168 may also be disposed within the gear recess 139, sandwiched between the front cover 137 of the transmission housing and the outer race 153 of the first bearing 150, thereby axially spaced from the inner race 151 and bearing ball 155 of the first bearing 150 from the front cover 137. In this case, the iBM's center hub 166 may be nested within the gear recess 139, radially inserted between the first bearing 150 and the input shaft 146.

[0098] It is likely desirable that the entire iBM device 160 be enclosed between the planetary gear set 122 and the front cover 137, such that the outer disk 162 of the iBM is axially inserted between the planetary gear carrier 130 and the first bearing 150 and also radially inserted between the ring gear 128 and the ICE input shaft 146. As in Figure 2 As best seen in the cross-sectional side view, the iBM device 160 can have a generally L-shaped axial section, wherein a cylindrical central hub 166 extends orthogonally from the radially inner periphery of the annular outer disk 162. It can be envisioned that... Figure 2 The shape, size, and position of the iBM device 160 may differ from those shown in the figures to accommodate other intended applications and accompanying packaging constraints. It is also conceivable that the iBM device 160 may be manufactured as a separate component mechanically mating with the ring gear 128 and the support bearing 150 (as shown), or alternatively, may be integrally formed with one or both of the gear 128 and the bearing 150.

[0099] Aspects of this disclosure have been described in detail with reference to illustrated embodiments; however, those skilled in the art will recognize that many modifications can be made thereto without departing from the scope of this disclosure. This disclosure is not limited to the precise constructions and compositions disclosed herein; any and all modifications, alterations, and variations apparent from the foregoing description are within the scope of this disclosure as defined by the appended claims. Furthermore, this concept expressly includes any and all combinations and sub-combinations of the foregoing elements and features.

Claims

1. An electrically variable transmission (EVT) assembly for a hybrid vehicle, the hybrid vehicle including an engine, a first motor and a second motor, a plurality of road wheels, and a final drive system drivably connected to one or more of the road wheels, the EVT assembly comprising: A transmission housing configured for mounting to the hybrid vehicle; An output shaft that is rotatable within the transmission housing and configured to be drivenly connected to the final drive system; An input shaft, which is rotatable within the transmission housing and configured to be drivenly connected to the crankshaft of the engine; The transfer gear set is rotatable within the transmission housing, drivably connected to the output shaft, and configured to drivably connect to the first motor shaft of the first motor; A first bearing, which is concentric with the input shaft, and includes a first inner race surrounded by a first outer race rigidly attached to the transmission housing; A planetary gear set, located inside the transmission housing, includes a sun gear concentric with and configured to be drivably connected to the second motor shaft of the second motor; a ring gear concentric with and drivably connected to the transfer gear set; and a planetary gear carrier concentric with and drivably connected to the input shaft, wherein the planetary gear carrier rotatably supports a plurality of planetary gears meshing with the sun gear and the ring gear. as well as An inverted bearing mount (iBM) device is located radially inside the transfer gear set within the transmission housing. The IBM device includes an annular outer disk rigidly attached to the ring gear and a cylindrical central hub extending axially from the outer disk and rigidly attached to the first inner race of the first bearing.

2. The EVT component according to claim 1, wherein, The iBM device, including the outer disk and the central hub, is integrally formed from rigid metal material into a single-piece structure.

3. The EVT component according to claim 1, wherein, The outer diameter (OD) disk surface of the outer disk is rigidly attached to the inner diameter (ID) gear surface of the ring gear, and the OD hub surface of the center hub is rigidly attached to the ID bearing surface of the first bearing.

4. The EVT component according to claim 1, wherein, The iBM device also includes a spacer ring that extends axially from the outer disk and surrounds the central hub, the spacer ring pressing against the first inner race and thereby separating the first bearing from the outer disk.

5. The EVT assembly of claim 1, further comprising a second bearing rotatably mounted to the input shaft, wherein, The center hub is concentric with the second outer race of the second bearing and is rigidly attached to the second outer race.

6. The EVT assembly according to claim 5, wherein, The iBM device further includes a retaining ring extending radially inward from the central hub, the retaining ring pressing against the second outer race and thereby axially retaining the second bearing inside the central hub.

7. The EVT assembly according to claim 5, wherein, The outer diameter (OD) hub surface of the center hub is rigidly attached to the inner diameter (ID) bearing surface of the first bearing, and the ID hub surface of the center hub is rigidly attached to the OD bearing surface of the second bearing.

8. The EVT component according to claim 1, wherein, The transmission housing includes a main housing, a front cover mounted on the main housing and receiving the input shaft therethrough, and an annular gear recess located on the inner surface of the front cover and rigidly attached to the first outer race, such that the first bearing is nested inside the gear recess.

9. A hybrid electric vehicle, comprising: The vehicle itself; Multiple road wheels are attached to the vehicle body; An internal combustion engine (ICE) assembly, which is attached to the vehicle body and includes a crankshaft configured to output engine torque generated by the ICE assembly; A first electric motor and a second electric motor are attached to the vehicle body and include a first motor shaft and a second motor shaft, the first motor shaft and the second motor shaft being respectively configured to output motor torque generated by the first electric motor and the second electric motor. The final drive system is drivably connected to one or more of the road wheels; as well as An electrically variable transmission (EVT) assembly, comprising: A transmission housing, which is installed inside the vehicle body; An output shaft, which is rotatable within the transmission housing and driven to be connected to the final drive system; An input shaft, which is rotatably and driveably connected within the transmission housing to the crankshaft of the ICE assembly; The transfer gear set is rotatable within the transmission housing, is drivably connected to the output shaft, and is drivably connected to the first motor shaft of the first electric motor; A first bearing, which is concentric with the input shaft, and includes a first inner race surrounded by a first outer race rigidly attached to the transmission housing; A planetary gear set, located inside the transmission housing, includes a sun gear concentrically and driveably connected to the second motor shaft of the second electric motor; a ring gear concentrically and driveably connected to the transfer gear set; and a planetary gear carrier concentrically and driveably connected to the input shaft, wherein the planetary gear carrier rotatably supports a plurality of planetary gears meshing with the sun gear and the ring gear; and An inverted bearing mount (iBM) device is located radially inside the transfer gear set within the transmission housing. The iBM device includes an annular outer disc and a cylindrical central hub integrally formed with and extending axially from the outer disc. The outer disc is rigidly attached to the annular gear, and the central hub is rigidly attached to the first inner race of the first bearing.

10. A method of assembling an electrically variable transmission assembly for a hybrid vehicle, the hybrid vehicle including an engine, a first motor and a second motor, a plurality of road wheels, and a final drive system drometically connected to one or more of the road wheels, the method comprising: A transmission housing is received, the transmission housing being configured for installation into the hybrid vehicle; The output shaft is rotatably mounted within the transmission housing, and the output shaft is configured to be driven to the final drive system; The input shaft is rotatably mounted within the transmission housing, and the input shaft is configured to be drivenly connected to the crankshaft of the engine; The transfer gear set is rotatably mounted in the transmission housing, the transfer gear set is driven to the output shaft and configured to be driven to the first motor shaft of the first motor; A first bearing concentric with the input shaft is installed, the first bearing including a first inner race surrounded by a first outer race; The first outer race is rigidly attached to the transmission housing; The planetary gear set is positioned inside the transmission housing. The planetary gear set includes a sun gear that is concentric with the second motor shaft of the second motor and configured to be driven to the second motor shaft; a ring gear that is concentric with the sun gear and driven to the transfer gear set; and a planetary gear carrier that is concentric with the input shaft and driven to the input shaft. The planetary gear carrier rotatably supports a plurality of planetary gears that mesh with the sun gear and the ring gear. The inverted bearing mount (iBM) device is positioned inside the transmission housing on the radially inner side of the transfer gear set, the iBM device including an annular outer disk and a cylindrical central hub extending axially from the outer disk; The outer disk is rigidly attached to the ring gear; as well as The cylindrical central hub is rigidly attached to the first inner race of the first bearing.

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