Gear synchronization controller and related gear synchronization method for preventing blocked shift

Abstract

A power transmitting gear set includes a gear synchronization controller configured to communicate with a driving gear, a driven gear, and a shift mechanism. In response to detecting a gear engagement command, the gear synchronization controller is configured to determine a rotational speed increment between a rotational speed of the driving gear and a rotational speed of the driven gear and compare the rotational speed increment to a predetermined rotational speed increment. In response to determining that the rotational speed increment is less than the predetermined rotational speed increment, the gear synchronization controller applies a rotational flapper function to the drive gear to concurrently apply a series of clockwise and counterclockwise rotational cycles to the drive gear during the axial movement of the shift mechanism, while the rotational speed increment is less than the predetermined rotational speed increment. The plurality of shift teeth are engaged with the plurality of gear teeth to prevent a blocked condition of the power transfer gear set while establishing the engagement relationship between the plurality of shift teeth and the plurality of gear teeth.

Description

Cross - Reference to Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 429,171, filed on December 1, 2022, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] The present disclosure generally relates to vehicle transmissions, such as vehicle engines. More specifically, the present disclosure relates to a method of operating a power transfer gear set associated with a wheel-end engine of a vehicle. Background Art

[0003] This section provides a general overview of background information, and the comments and examples provided in this section are not necessarily prior art to the present disclosure.

[0004] Various powertrain systems in automotive, truck, and certain off-highway vehicle applications obtain power from a central prime mover and use mechanical devices such as transmissions, transaxles, propeller shafts, and drive axles to distribute the power to at least one wheel. These configurations work well when the prime mover is large or heavy, such as various internal combustion engines (“ICEs”) and centralized electric drive axles. However, there is increasing interest in alternative arrangements of prime movers that can provide better environmental performance, eliminate mechanical powertrain components, and reduce vehicle weight, providing more space for passengers and payload.

[0005] “On wheel,” “in-wheel,” or “near-wheel” motor configurations (which are all considered in-wheel or wheel-end motors according to the present disclosure) are an alternative arrangement to traditional internal combustion engines (ICEs) or centralized electric bridge prime movers that distribute the prime mover function to each or some of the multiple wheels through one or more electric or non-electric engines (such as hydrostatic engines) disposed on, inside, or near the multiple wheels. Specifically, when implementing an electric mobility solution using in-wheel motors (IWMs), an electric vehicle can be equipped with two such motors in a rear-wheel or front-wheel drive configuration, or four IWMs in an all-wheel drive configuration. Other IWM configurations with different numbers are also feasible, with a minimum of one IWM and no upper limit.

[0006] These wheel-end engines typically include a power transmission gear set having a driving gear and a driven gear for transmitting torque / power from the engine to the vehicle's wheels. The power transmission gear set may include a shifting mechanism that can be advanced towards and selectively coupled with one of the driving gear or the driven gear (depending on which gear the shifting mechanism is operably coupled to) to effect the transmission of torque / power from the engine. However, as Figure 1 shown, both the shifting mechanism and the driving gear or the driven gear include corresponding shifting teeth 10 and gear teeth 12 that will abut each other (i.e., directly tooth-to-tooth) during the axial movement of the shifting mechanism, thereby preventing the shifting teeth from being operably coupled with the gear teeth and creating a blocked shift condition for the power transmission gear set. If, as Figures 12 to 13 shown, the shifting mechanism moves (e.g., pushes) one of the driving gear or the driven gear towards and into engagement with the other of the driving gear or the driven gear (rather than the movement of the shifting mechanism being to establish an operable coupling relationship between the driving gear and the driven gear), then Figure 1 the shifting teeth 10 in Figure 1 can be represented as the driving gear teeth 10 of the driving gear, and the gear teeth 12 can be represented as the driven gear teeth 12 of the driven gear. Regardless of the arrangement, a blocked shift condition is more likely to occur when the speed difference between the driving gear and the driven gear is low / zero because the shifting teeth 10 and the gear teeth 12 are more likely to be arranged axially tooth-to-tooth (as Figures 2 to 3 shown), and thus there is not enough speed difference or positional difference to form an offset relationship (as Figure 3 shown), such that when the shifting mechanism applies a force, the tapered edges of the corresponding teeth 10, 12 will contact each other, allowing the corresponding teeth 10, 12 to slide down along the tapered edges to the gear engagement state during the movement of the shifting mechanism (as

[0007] Referring to FIG. 4, a power transmission gear set in a conventional ICE transmission typically adds at least one mechanical synchronizer 14 having multiple mechanical components to synchronize the rotation of the driven gear and the driving gear to the same speed and prevent blocked shift conditions. More specifically, these conventional mechanical synchronizers 14 typically include a shift sleeve 16 (also known as a slider) as a shift mechanism, multiple struts 18 (or keys or balls, depending on the specific design), a blocking ring 20 (also known as a detent ring), and a synchronizer cone 22 (applied to the target driving gear). In operation, when the shift sleeve 16 is moved to shift gears, the shift sleeve 16 slides axially and pushes the struts 18, and the struts 18 then push the blocking ring 20. Then, the blocking ring 20 is pushed onto the synchronizer cone 22, and friction causes the shaft speeds to equalize. At the same speed, the keys and notches on the blocking ring align, and then the slider teeth engage with the teeth on the outer diameter of the blocking ring 20. As the applied force increases, the frictional force causes the rotational speeds of the shift sleeve 16, the blocking ring 20, and the synchronizer cone 22 to be the same. When the shift sleeve 16 engages with the gear teeth on the blocking ring 20 and the gear teeth on the synchronizer cone 22, the gear shift is completed.

[0008] However, using a mechanical synchronizer 14 to synchronize the driving gear and the driven gear requires multiple mechanical components, which increases the cost, complexity, and the overall footprint of the power transmission gear set (i.e., larger size requirements). Therefore, using a mechanical synchronizer in the power transmission gear set of an in-wheel engine cannot achieve the goals pursued by lightweight vehicles that eliminate mechanical driveline components and provide more space for passengers and payloads. Therefore, there is still a need for an alternative method to synchronize the driving gear and the driven gear in the power transmission gear set, especially when used in combination with an in-wheel engine as an alternative transmission for an electric vehicle. SUMMARY OF THE INVENTION

[0010] The present invention generally relates to a gear synchronization controller and an associated method that synchronizes a driving gear and a driven gear of a power transmission gear set by applying a rotational baffle function to the driving gear, particularly during a "zero speed" engagement command of a shift mechanism, to prevent a blocked shift condition from occurring. More specifically, when it is determined that a gear engagement command of the power transmission gear set occurs during a low-speed or zero-speed difference state between the driving gear and the driven gear, which means there may be direct tooth contact between the shift teeth of the shift mechanism and the gear teeth of the driving gear (or in an alternative configuration, the gear teeth of the driving gear and the gear teeth of the driven gear), a rotational baffle function is applied to the driving gear in a stable manner or in a series of pulses based on at least one of frequency, torque, or rotational speed characteristics, so that during the axial movement of the shift mechanism, before the shift gear teeth and the driving gear teeth (or in an alternative configuration, the gear teeth on the driven gear and the gear teeth on the driving gear) first come into contact, the driving gear is simultaneously moved (i.e., rotated), thereby increasing Figures 2 to 3the probability of the conical offset relationship shown and prevent Figure 1 the blocking shift condition shown. The term "zero speed" used in the present invention refers not only to when the vehicle is at a standstill, but also to when the engine speed is within a small incremental speed range compared to the gear set speed, and the gear set speed is converted from the road speed through the ratio relationship of the wheels and the associated gear set.

[0011] As can be understood from the more detailed disclosure below, during these "zero speed" engagement conditions (i.e., when the speed difference between the speed of the driving gear and the speed of the driven gear is less than a predetermined low speed or zero speed difference), the use of a gear synchronization controller and related control methods to achieve gear synchronization does not rely on a set of mechanical components (i.e., a mechanical synchronizer), thereby reducing costs (material costs and maintenance costs) and saving packaging space for the power transmission gear set. From another perspective, the control method can be customized to support wheel-end solutions for different models / codes of wheel-end engines. For example, if the current design of the electric motor and / or the associated power transmission gear set is scaled up or down according to the needs of a specific end user, although the components of the shift mechanism may change, there is no need to cast / forge / stamp new mechanical components related to gear synchronization, thereby further saving engineering and capital equipment costs.

[0012] Other advantages will be recognized in view of the more detailed description of the present invention below. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings described herein are only for illustrating selected aspects and not all possible embodiments, and are not intended to limit the scope of the present disclosure.

[0014] Figure 1 Shows a blocking shift condition of a power transmission gear set, where during the axial movement of the shift mechanism towards one of the driving gear or the driven gear, the shift teeth of the shift mechanism and the gear teeth of the driving gear or the driven gear are in an adjacent (i.e., tooth-to-tooth) relationship.

[0015] Figure 2 Shows that during the axial movement of the shift mechanism, the shift teeth and the gear teeth are in an offset relationship to allow the shift teeth and the gear teeth to move downward along their respective conical edges to establish an engaged state.

[0016] Figure 3 Shows the shift teeth and the gear teeth in an engaged state.

[0017] FIG. 4 is a perspective view of a prior art mechanical synchronizer used in a power transmission gear set of a conventional ICE transmission for synchronizing a driving gear with a driven gear to prevent a blocking shift condition.

[0018] Figure 5A cross-sectional view of a power transmission gear set for an exemplary in-wheel motor, showing a low-speed slider clutch of a shift mechanism that is operably coupled to and slidable relative to an output gear (driven gear), and in an actuated position to engage shift teeth with gear teeth and establish a selective coupling between the output gear (driven gear) and a ring gear (driving gear) of a first-stage planetary gear reducer assembly, and to place the power transmission gear set and the in-wheel motor in a low-speed condition.

[0019] Figure 6 A cross-sectional view of a power transmission gear set for an exemplary in-wheel motor, showing a high-speed slider clutch of a shift mechanism in an actuated position during a high-speed condition of the power transmission gear set and the in-wheel motor.

[0020] Figure 7 A cross-sectional view of an alternative arrangement of a power transmission gear set, where the shift mechanism is alternatively operably coupled to and slidable relative to a driving gear.

[0021] Figure 8 A cross-sectional view of an alternative arrangement of a power transmission gear set, showing the shift mechanism axially slid into an actuated position to bring shift teeth into an engaged relationship with gear teeth alternately disposed on a driven gear.

[0022] Figure 9 A schematic diagram of a gear synchronization controller for a power transmission gear set.

[0023] Figure 10 A flowchart showing a gear synchronization method executed by a gear synchronization controller during a determined "zero speed or low speed" engagement command to avoid blocked shift conditions.

[0024] Figure 11 A side view showing a shift gear and gear teeth arranged in a 50% gear overlap relationship.

[0025] Figure 12 A cross-sectional view of another alternative arrangement of a power transmission gear set, where the driving gear has driving gear teeth and the driven gear has driven gear teeth.

[0026] Figure 13 Is Figure 12 A cross-sectional view of a power transmission gear set, showing one of a driving gear or a driven gear axially slid towards the other by a shift mechanism to bring driving gear teeth on the driving gear into an engaged relationship with driven gear teeth on the driven gear. Detailed Description

[0027] Exemplary aspects of a gear synchronization controller and related control methods for implementing a power transmission gear set (e.g., IWM), particularly under low-speed or zero-speed engagement conditions, will now be described more fully. Although the control methods will be described for low-speed or zero-speed engagement conditions, the principles of the gear synchronization controller and related control methods can also be applied under high-speed engagement conditions without departing from the scope of the present invention. Each example embodiment is provided so that the present disclosure is thorough and conveys the full scope of the inventive concepts, features, and advantages to those skilled in the art. To this end, numerous specific details are set forth, such as examples of specific components, devices, mechanisms, flowcharts, or processing steps related to algorithms and methods, to provide a thorough understanding of each embodiment related to the present disclosure. However, those skilled in the art should understand that not all of the specific details described herein are required, and the example embodiments can be embodied in many different forms and should not be construed or understood as limiting the scope of the present disclosure. Additionally, the methods described in more detail below are applicable to partially or fully electric vehicles, power transmission gear sets connected to one-way or two-way rotating engines, and high-speed engagement conditions of the high-speed slider clutch described above without departing from the scope of the present invention.

[0028] Figures 5 to 6 A lubricant-supported electric motor 30 is shown in accordance with one aspect of the present disclosure. However, although the control method for gear synchronization will be described in detail in connection with the lubricant-supported electric motor 30, it should be understood that the lubricant-supported electric motor 30 is only provided for exemplary disclosure, and the gear synchronization control method can be applied to other types of electric or non-electric engines (e.g., roller bearing motors or other motors for wheel ends and even non-vehicle applications, as well as one-way / two-way rotating engines such as hydrostatic engines or pneumatic engines) without departing from the scope of the present invention. In this exemplary arrangement, however, the lubricant-supported electric motor 30 includes a stator 32 and a rotor 34 that extends along an axis A and is rotatably disposed within the stator 32, thereby defining a gap G between the stator 32 and the rotor 34. A lubricant 38 is disposed within the illustrated gap G for individually supporting the rotor 34 within the stator 32 and ensuring continuous contact between these components. Thus, the lubricant 38 can act as a buffer (e.g., a suspension) between the rotor 34 and the stator 32, thereby minimizing or preventing contact between them. In other words, the lubricant 38 can prevent direct contact between the stator 32 and the rotor 34 and enable the lubricant-supported electric motor 30 to have good resistance to shock and vibration loads due to the presence of the lubricant 38. Additionally and / or, a substantially incompressible lubricant 38 can also be used to minimize the gap G between the stator 32 and the rotor 34.

[0029] As Figures 5 to 6Further shown, the stator 32 defines a passage 40 that is in fluid communication with the gap G for introducing the lubricant 38. However, without departing from the scope of the present disclosure, the passage 40 can be provided on any other component of the lubricant-supported motor 30. According to one aspect, the lubricant 38 can be circulated or pumped through the passage 40 and into the gap G in various ways. For example, a high-pressure source (e.g., a pump) 42 of the lubricant 38 can be fluidly coupled to a low-pressure source (e.g., an oil sump) 44, and the lubricant 38 can move from the high-pressure source 42 to the low-pressure source 44, entering the gap G through the passage 40. The rotation of the rotor 34 relative to the stator 32 can operate as a self-pump to drive the lubricant 38 through the passage 40 and into the gap G.

[0030] As Figures 5 to 6 Further shown, the rotor 34 is operatively interconnected to a power transmission gear set 50 for coupling the lubricant-supported motor 30 to at least one wheel 44 of an electric vehicle, thereby transmitting torque / power from the lubricant-supported motor 30 to drive the wheel 44 of the electric vehicle. The power transmission gear set 50 includes a drive gear 46 and a driven gear 48, and each of the drive gear and the driven gear is rotatable about the axis A. In Figures 5 to 6 the exemplary arrangement shown, the power transmission gear set 50 can include a first-stage planetary gear reducer assembly 52 that is operatively connected to the rotor 34 to rotate therewith. In this exemplary arrangement, the first-stage planetary gear reducer assembly 52 is driven by a sun gear and includes a sun gear 54 that is rotatably aligned along the axis A and is in an operatively interconnected relationship with the rotor 34 through a rotor shaft 56. Applicant's U.S. Patent Application No. 17 / 575,677 describes and shows an alternative method of arranging the lubricant-supported motor 30 and establishing an operable connection between the rotor 34 and the sun gear 54, the disclosure of which is incorporated herein by reference as a suitable alternative embodiment for use in conjunction with the present control method. As Figures 5 to 6 Further shown, the first-stage planetary gear assembly 52 includes a planet carrier 58 and a ring gear 60. The planet carrier 58 rotatably supports a plurality of planetary gears (not explicitly shown) that are radially outwardly arranged and are operatively connected to the sun gear 54. The ring gear 60 is concentrically arranged around the planetary gears and is operatively connected to the planetary gears for rotating about the axis A in response to the rotation of the sun gear 54. As Figure 6As shown, the ring gear 60 serves as the drive gear 46 under low-speed shifting conditions and has a plurality of gear teeth 12 that are concentrically arranged around the ring gear 60 and radially inwardly extend toward the axis A. However, as can be understood from the disclosure below, if the gear operating principle is applied to high-speed shifting conditions, the sun gear 54 can serve as the drive gear 46, under which conditions the gear teeth 12 will radially outwardly extend from the axis A. As Figures 5 to 6 Further shown, in either arrangement, the power transmission gear set 50 includes an output gear 62 that is rotatably aligned along the axis A and is disposed adjacent to the sun gear 54 to serve as the driven gear 48.

[0031] As Figures 5 to 8 shown, the power transmission gear set 50 includes a shifting mechanism 64 that is operably coupled to one of the driven gear 48 (see Figures 5 to 6 ) or the drive gear 46 (see Figures 7 to 8 ) to rotate therewith. The other of the driven gear 48 or the drive gear 46 (in a non-shifting state, the shifting mechanism 64 is not operably coupled thereto) has a plurality of gear teeth 12 concentrically arranged around the axis A. For example, as described above with respect to the Figures 5 to 6 illustrated embodiment, if the shifting mechanism 64 is operably coupled to the driven gear 48 (the output gear 62 in this exemplary structure), the drive gear 46 (the ring gear 60 in this exemplary structure) can present gear teeth 12. However, as Figures 7 to 8 shown, if the shifting mechanism 64 is operably coupled to the drive gear 46, the driven gear 48 (such as the output gear 62) can present gear teeth 12 concentrically arranged around the axis A. Regardless of which arrangement, the shifting mechanism 64 has a plurality of shifting teeth 10 concentrically arranged around the axis A, and the shifting mechanism 64 can axially slide relative to one of the drive gear 46 or the driven gear 48 to which it is operably connected in response to a gear engagement command, advancing the shifting teeth 10 toward and engaging with the gear teeth 12, thereby establishing an engagement relationship and selectively transmitting torque from the drive gear 46 to the driven gear 48. As will be described in more detail below, the shifting mechanism 64 can achieve transmitting adjustable torque to a final drive module (not explicitly shown but operably serially connected or connected downstream of the output gear 62) to transmit power / torque to the vehicle wheels 44.

[0032] In an exemplary arrangement, the shift mechanism 64 may include at least one slider clutch 66, 68 which may rotate with the output gear 62 and be axially slidable relative to the output gear 62 (in the exemplary arrangement), from a neutral position to an engaged position, wherein in the neutral position, at least one slider clutch 66, 68 is spaced from and in a non-engaged relationship with the first stage planetary gear assembly 52, and wherein in the engaged position, at least one slider clutch 66, 68 axially moves towards the first stage planetary gear assembly 52 and forms a selective engagement relationship therewith, thereby establishing a selective coupling between the first stage planetary gear assembly 52 and the output gear 62. Although the shift mechanism 64 will be described in connection with a slider clutch, the shift mechanism 64 may also take a variety of different forms, such as wet or dry plate clutches, cone synchronizers, etc., to achieve a variety of different functions of the power transmission gear set 50 (e.g., Figure 6 the high gear condition / function shown, and Figure 5 the low gear condition function shown).

[0033] The shift mechanism 64 preferably includes a plurality of slider clutches 66, 68 for establishing a variety of functions (i.e., high and low gears) for the power transmission gear set 50. In this preferred arrangement, as Figures 5 to 6 shown, the plurality of slider clutches 66, 68 includes a high speed slider clutch 66 and a low speed slider clutch 68 which are concentrically and slidably arranged and are commonly fixed to the output gear 62 for rotation therewith. More specifically, the high speed slider clutch 66 is received concentrically and slidably along an outer sliding gear surface 70 of the output gear 62 for axially sliding from the neutral position (where no rotational torque is directly transmitted from the first planetary gear assembly 52 to the output gear 62) to Figure 6 the corresponding engaged position shown, wherein the high speed slider clutch 66 moves into an operatively interconnected relationship with the sun gear 54. In this engaged position, rotation of the shown sun gear 54 drives rotation of the high speed slider clutch 66 and the output gear 62 operatively connected to the high speed slider clutch 66, thereby establishing a high gear for the power transmission gear set 50 and the associated lubricant supported electric motor 30.

[0034] The low speed slider clutch 68 is also received concentrically and slidably along an outer sliding clutch surface 72 of the high speed slider clutch 66 for axially sliding from the neutral position to Figure 5The corresponding engagement position shown, in which the low-speed slider clutch 68 is moved to an operably interconnected relationship with the ring gear 60. In the engagement position, the low-speed slider clutch 68 includes shift teeth 10 that engage gear teeth 12 extending along the ring gear 60 such that rotation of the ring gear 60 drives corresponding rotation of the low-speed slider clutch 68 and the output gear 62. The low-speed slider clutch 68 is operably connected to the output gear 62 through the high-speed slider clutch 66 (i.e., since the output gear 62, the high-speed slider clutch 66, and the low-speed slider clutch 68 are concentrically arranged with each other, they rotate synchronously about the axis A simultaneously). In this arrangement, the low-speed slider clutch 68 establishes a low gear for the power transmission gear set 50 and the associated lubricant-supported motor 30.

[0035] As Figures 5 to 6 Further shown, the power transmission gear set 50 may include at least one low-speed actuator 74 and at least one high-speed actuator 76. The low-speed actuator 74 is operably connected to the low-speed slider clutch 68, and the high-speed actuator 76 is operably connected to the high-speed slider clutch 66 for moving the slider clutches 66, 68 from their neutral positions to the engagement positions. The gear synchronization controller 78 is electrically connected to the low-speed actuator 74 and the high-speed actuator 76 for controlling their actuation according to vehicle conditions and the gear required (e.g., low gear or high gear) by the power transmission gear set 50 and the associated lubricant-supported motor 30 under low-speed or high-speed shift conditions.

[0031] Figure 7 A block diagram of an exemplary gear synchronization controller 78 is shown. The gear synchronization controller is configured to (and / or includes circuitry configured to) implement the functions of the systems and methods described herein. The systems described herein may be implemented as a single computing device, multiple computing devices, etc., which are configured to perform functions related to the systems and methods of the present disclosure individually and / or jointly.

[0032] The gear synchronization controller 78 may include a control circuit 224 (which may be, for example, one or more processors or processing devices, a central processing unit processor (CPU), an integrated circuit, or any suitable computing or computational device), an operating system 226, a memory 228, executable code 230, an input device or circuit 232, and an output device or circuit 234. The control circuit 224 (or one or more controllers or processors, possibly across multiple units or devices) may be configured to implement the functions of the systems and methods described herein. According to embodiments of the present disclosure, multiple gear synchronization controllers 78 may be included in the system, and one or more gear synchronization controllers 78 may be components of the system. The various components of the gear synchronization controller 78 may be implemented using the same or different circuits, the same or different processors or processing devices, etc.

[0033] The operating system 226 may be or may include any code segment (e.g., a code segment similar to the executable code 230 described herein) that is designed and / or configured to perform tasks involving coordinating, scheduling, arbitrating, supervising, controlling, or otherwise managing the operation of the control circuit 224 shown, such as scheduling the execution of software programs or tasks or enabling software programs or other hardware modules or units to communicate. The operating system 226 may be a commercial operating system. It should be noted that the operating system 226 may be an optional component (e.g., in some embodiments, the system may include a computing device that does not require or does not include the operating system 226). For example, a computer system may be or may include a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a network controller (e.g., a CAN bus controller), an associated transceiver, a system-on-chip (SOC), and / or any combination of the above that can be used without an operating system.

[0034] The memory 228 may be or may include, for example, random access memory (RAM), read-only memory (ROM), dynamic RAM (DRAM), synchronous DRAM (SD-RAM), double data rate (DDR) memory chips, flash memory, volatile memory, non-volatile memory, a cache, a buffer, a short-term memory unit, a long-term memory unit, or other suitable memory units or storage units. The memory 228 may be or may include multiple potentially different storage units. The memory 228 may be a non-transitory readable medium of a computer or processor, or a non-transitory storage medium of a computer, such as RAM.

[0035] The executable code 230 can be any executable code, such as an application, program, process, task, or script. The executable code 230 can be executed by the control circuit 224 and may be executed under the control of the operating system 226. Although only a single executable code 230 is shown in the figure for clarity, according to certain embodiments of the present disclosure, the system may include multiple executable code segments similar to the executable code 230, which can be loaded into the memory 228 and cause the control circuit 224 to execute the methods described herein. In applicable cases, the terms "process" and "executable code" may be used interchangeably herein. For example, the verification, validation, and / or authentication of a process may mean the verification, validation, and / or authentication of executable code.

[0036] In some examples, the memory 228 may include non-volatile memory having the storage capacity of a storage system. In other examples, the gear synchronization controller 78 may include a storage system or communicate with a storage system. Such a storage system may include, for example, flash memory known in the art, memory built into or embedded in a microcontroller or chip, a hard disk drive, a recordable CD (CD-R) drive, a Blu-ray Disc (BD), a universal serial bus (USB) device, or other suitable removable and / or fixed storage units. Content can be stored in the storage system, loaded into the memory 228 from the storage system, and processed by the control circuit 224.

[0037] The input circuit 232 can be or can include any suitable input device, component, or system, such as a physical sensor (e.g., an accelerometer, thermometer, microphone, analog-to-digital converter, etc.), a detachable keyboard or keypad, a mouse, etc. The output circuit 234 can include one or more (possibly detachable) displays or monitors, motors, servo motors, speakers, high-side drivers, low-side drivers, and / or any other suitable output device. Any applicable input / output (I / O) device can be connected to the control circuit 224. For example, a wired or wireless network interface card (NIC), a universal serial bus (USB) device, a JTAG interface, or an external hard disk drive can be included in the input circuit 232 and / or the output circuit 234. It can be understood that any appropriate number of input devices and output devices can be operatively connected to the control circuit 224. For example, a technician or engineer can use the input circuit 232 and the output circuit 234 to connect to the control circuit 224, update software, etc.

[0038] Embodiments may include articles such as non-transitory computer or processor-readable media, or non-transitory computer or processor storage media (e.g., memory, disk drive, or USB flash drive), which encode, include, or store instructions (e.g., computer-executable instructions that, when executed by a processor or controller, perform the methods disclosed herein), storage media (e.g., memory 228), computer-executable instructions (e.g., executable code 230), and a controller (e.g., control circuit 224).

[0039] The storage media may include, but is not limited to, any type of disk, including magneto-optical disks, semiconductor devices (e.g., read-only memory (ROM), random access memory (RAM) (e.g., dynamic RAM (DRAM), erasable programmable read-only memory (EPROM), flash memory, electrically erasable programmable read-only memory (EEPROM), magnetic cards, or optical cards), or any type of medium suitable for storing electronic instructions, including programmable storage devices.

[0040] Embodiments of the present disclosure may include the following components, such as, but not limited to: multiple central processing units (CPUs) or any other suitable general-purpose or special-purpose processor or controller (e.g., a controller similar to the control circuit 224), multiple input units, multiple output units, multiple memory units, and multiple storage units, etc. The system may also include other suitable hardware components and / or software components. In some embodiments, the system may include or may be, for example, a personal computer, a desktop computer, a mobile computer, a laptop computer, a notebook computer, a terminal, a workstation, a server computer, a personal digital assistant (PDA) device, a tablet computer, a network device, or any other suitable computing device.

[0041] In some embodiments, the system may include or may be, for example, multiple components that include corresponding multiple central processing units, e.g., multiple CPUs as described above, multiple CPUs embedded in an on-board system or network, multiple chips, FPGAs, or SOCs, microprocessors, transceivers, microcontrollers, multiple computers or network devices, any other suitable computing device, and / or any combination thereof. For example, the system described herein may include one or more devices, such as the control circuit 224.

[0042] As previously described, when the controller 78 receives a "low speed or zero speed" engagement command, which is a request to switch the power transmission gear set 50 from a parked or stationary state of the electric vehicle to a low gear condition, or other "zero speed or low speed" states as explained in the introductory section, where there is a low speed or zero speed differential between the driven gear 46 and the drive gear 48 (to be explained in more detail below), the likelihood of direct tooth-to-tooth contact between the shift teeth 10 on the shift mechanism 64 (e.g., the low speed slider clutch 68) and the gear teeth 12 on the driven gear or the drive gear 46, 48 (e.g., the ring gear 60) increases. If such contact occurs, it will result in a blocked shift condition for the power transmission gear set 50. Therefore, the gear synchronization controller 78 is configured to operate a gear synchronization method for the driven gear and the drive gears 46, 48 based on applying the rotational baffle function (e.g., frequency force and / or speed) to the drive gear 46 (i.e., the ring gear 60) to prevent a blocked shift condition from occurring.

[0043] More specifically, the gear synchronization controller 78 is electrically connected to the drive gear 46, the driven gear 48, and the shift mechanism 54, and when the gear synchronization controller 78 determines that there is a "zero speed or low speed" gear engagement command, indicating that there may be direct tooth-to-tooth contact between the shift teeth 10 and the gear teeth 12, it applies a rotational baffle function to the drive gear 46 (e.g., the ring gear 60) in a stable manner or in the form of a series of rotational pulses based on at least one of frequency, torque, or rotational speed characteristics, so as to, during the actuation and axial movement of the sliding mechanism 54, but before the shift teeth 10 first come into contact with the gear teeth 12, simultaneously move (i.e., rotate) the drive gear 46 (e.g., the ring gear 60) about the axis A, thereby increasing the likelihood of the conical offset relationship as Figures 2 to 3 shown, and preventing the occurrence of Figure 1 the blocked shift condition shown. Although the remainder of the control method will be described in connection with the low speed condition and thus the rotational engine baffle function is applied to the ring gear 60 as the drive gear 46, the gear synchronization control method can also be used to apply the rotational baffle function to the sun gear 54 as the drive gear 46 when a high speed engagement command is requested and the high speed slider clutch 66 is actuated and axially moved to establish the high speed condition, without departing from the scope of the present invention. However, the rotational baffle function is preferably only applied to the drive gear 46 (e.g., the gears of the first stage planetary gear assembly 52) that maintains rotational ability during vehicle operation, rather than the driven gear 48 (e.g., the output gear 62), because the movement ability of the driven gear is minimal, such as under low speed conditions.

[0044] AsFigure 10 As shown, the gear synchronization method executed by the gear synchronization controller 78 begins at step 300, where the gear synchronization controller 78 detects a gear engagement command sent to the power transmission gear set 50. In response to detecting the gear engagement command, the gear synchronization controller 78 proceeds to step 302 to determine a speed increment between a speed of the drive gear 46 and a speed of the driven gear 48. In step 304, the gear synchronization controller 78 continues to compare the speed increment with a predetermined "zero or low" speed increment to determine whether the speed increment is less than the predetermined "zero or low" speed increment. For example, when the gear synchronization method is used in conjunction with a low-speed shift condition of the power transmission gear set 50, the predetermined "zero or low" speed increment may be set to 20 rpm. However, other predetermined "zero or low" speed increments may be used without departing from the scope of the present disclosure. In response to determining that the speed increment is less than the predetermined speed increment, the gear synchronization controller 78 proceeds to step 306 to initiate applying a rotational blocking function to the drive gear 46. In response to the gear engagement command, during an initial axial movement of the shift mechanism 54, the rotational blocking function applies a series of clockwise and counterclockwise rotation cycles to the drive gear 46 to prevent the power transmission gear set 50 from being in a blocked condition during an initial establishment of the meshing relationship between the shift teeth 10 and the gear teeth 12.

[0045] As will be described in more detail in the various embodiments discussed below, in response to activation of the gear synchronization controller 78, the rotational blocking function, which consists of a series of clockwise and counterclockwise rotation cycles applied to the drive gear 46, is preferably based on at least one of the following plurality of frequency, torque, and / or speed functions (a to k): a) Frequency — The period of time during which the drive gear rotates in a clockwise / counterclockwise cycle about an axis by the gear synchronization controller; if followed by "b", "a" is the initial frequency used in a multi-frequency mode. b) End Frequency — The final frequency of rotation in the rotational blocking function. c) Frequency Offset Duration — The period of time taken to go from the initial frequency to the final frequency; the change in frequency is typically distributed over this period of time, although it may not be proportional. d) Positive Percentage — The percentage of the frequency applied to the forward drive gear. The remaining portion of the frequency cycle is applied to the reverse drive gear. Supports non-proportional frequencies. e) Initial Rotation Direction — Indicates the initial direction of rotation of the drive gear when the controller activates the rotational blocking function; 1 = forward, -1 = reverse. f)Torque — The initial rotational force applied to the drive gear when the gear synchronization controller activates the rotational shutter function. If followed by "g", "f" represents the starting force used in the multi-torque application mode. If not followed by "i", it means that in the rotational shutter function, the torques applied in the forward and reverse directions are the same. g) Termination Torque — The final torque level applied to the drive gear in the rotational shutter function. h) Torque Change Duration — The time period used from the initial torque level to the final torque level, during which the change in torque is typically distributed, although it may not be proportional. i) Negative Torque — When used in conjunction with "f", "I" represents the negative torque applied to the drive gear. If followed by "j", "i" represents the starting force used in the multi-torque application mode. j) Negative Termination Torque — The final negative torque level applied to the drive gear in the rotational shutter function. k) Negative Torque Transition Duration — The time period used from the initial negative torque level to the final negative torque level, during which the change in torque is typically distributed, although it may not be proportional.

[0046] Each of the clockwise and counterclockwise rotation cycles in a series of clockwise and counterclockwise rotation cycles has a rotational shutter frequency, which consists of a calibratable time period between the movement of the drive gear 46 in the clockwise direction and the movement in the counterclockwise direction. For example, the engine shutter frequency is 10 Hertz (Hz), and the function RotationalShutter(a = 10) indicates that one cycle is completed every 100 milliseconds (ms) for the engine direction change. In one embodiment, the rotational movement of the drive gear 46 in the clockwise and counterclockwise directions in each rotation cycle is equal and accounts for 50% of the rotational shutter frequency. For example, for a 10 Hz engine shutter frequency, it rotates 5 Hz (50 ms) in the clockwise direction and 5 Hz (50 ms) in the counterclockwise direction. According to the gear tooth interface design, an appropriate minimum frequency can be selected to ensure the free rotational movement of the drive-side gear, so that when the gear meshing force actively pushes the gear set closer, tapered edge contact can be achieved.

[0047] In another embodiment of the gear synchronization control, the rotational shutter frequency can vary over a period of time and can be adjusted from a first rotational cycle in the series of clockwise and counterclockwise rotational cycles to a last rotational cycle in the series of clockwise and counterclockwise rotational cycles. For example, the rotational shutter frequency can be adjusted from 2 Hz in the first rotational cycle to 20 Hz in the last rotational cycle over a calibratable period of time. For example, the function RotationalShutter(a = 2, b = 20, c = 3) distributes an engine shutter frequency from 2 Hz to 20 Hz evenly over 3 seconds to the drive gear 46. In a related embodiment, the frequency change can be made in a non-uniform distribution manner. The advantage of changing the applied frequency over time is that it can minimize the actual applied frequency required for the shift teeth 10 (e.g., on the low-speed slip clutch 68) and the gear teeth 12 (e.g., on the ring gear 60) when the gear sets engage, thereby minimizing the likelihood of audible noise.

[0048] In another embodiment of the gear synchronization control, a disproportionate shutter frequency is set considering a rotational direction of the driven gear. For example, the function RotationalShutter(a = 10, d = 75), where the clockwise and counterclockwise rotational movements of the driving gear in each rotation cycle are not equal. For example, in the disproportionate shutter frequency embodiment, a shutter frequency (e.g., 10 Hz) is applied to the driving gear, where a positive rotational frequency (i.e., the larger one of the clockwise or counterclockwise movements) persists for, for example, 75% of the relevant time period in the frequency, and a negative rotational frequency (i.e., the smaller one of the clockwise or counterclockwise movements) persists for the remaining 25% of the shutter frequency time period. Knowing the rotational direction of the driven gear can be used to determine the cycle portion representing the positive cycle (larger) in the shutter frequency. For example, if the driven gear 48 represents forward movement and clockwise rotation corresponds to the forward direction, the same 10 Hz may be disproportionately divided, where the forward (i.e., clockwise) rotational direction in the cycle accounts for 75% of the positive rotational frequency cycle and the shutter frequency (e.g., if the shutter frequency is 10 Hz, 75 ms of clockwise rotation), and the reverse accounts for the remaining 25% of the negative rotational frequency cycle and cycle time (25 ms of counterclockwise rotation). If the driven gear 48 indicates reverse movement, i.e., counterclockwise rotation, the engine shutter frequency can be reversed to the function RotationalShutter(a = 10, d = 25); indicating that the engine shutter frequency is 10 Hz, where 25% of the cycle is forward movement (i.e., clockwise rotational movement) and 75% of the cycle is backward movement (i.e., counterclockwise rotational movement). By utilizing a disproportionate engine shutter, the gear set is more likely to engage in the desired travel direction. This minimizes the "jitter" effect that the operator may encounter by moving the driving gear 46 in the opposite direction, engaging the gears, and then applying torque in the desired direction.

[0049] In another embodiment of the gear synchronization control, gear position information (i.e., a relative position of the shift tooth 10 with respect to the gear tooth 12) is used to determine the initial direction of the shutter frequency. For example, if the gear synchronization controller 78 determines that the gear overlap between the shift tooth 10 (e.g., on the low-speed slider clutch 68) and the gear tooth 12 (e.g., on the ring gear 60) has a 50% overlap, as Figure 11As shown, the gear synchronization controller 78 determines an initial rotational direction of the drive gear 46 that will minimize the travel required for the shift teeth 10 to contact the tapered edges of the gear teeth 12 (and for the shift teeth 10 and the gear teeth 12 to be in an aligned engagement relationship), and implements the initial rotational direction in the initial clockwise or counterclockwise direction for each rotational cycle. For example, the function RotationalShutter(a = 10, d = 25, e = -1) represents a rotational shutter frequency of 10 Hz, where 25% of the cycles are forward motion and 75% of the cycles are backward motion, while the first engine moves in the reverse direction. By minimizing the travel required for gear engagement between the shift teeth 10 and the gear teeth 12, torque interruption is also minimized. Initiating the rotational shutter frequency in the opposite direction increases the rotational travel distance of the drive gear before tapered edge contact; thus increasing the torque interruption time.

[0050] In a similar manner, the gear synchronization controller 78 is configured to apply a shutter torque, which is a calibrated level of torque applied to the drive gear during rotational motion. In other words, the gear synchronization controller 78 can initiate the application of a shutter torque during rotational motion in each of the clockwise and counterclockwise directions for each rotational cycle. For example, in one embodiment, the rotational shutter torque is 30 Nm, and the function RotationalShutter(a = 10, f = 30) represents that when the drive gear is shuttered at a frequency of 10 Hz, a rotational force of 30 Nm is applied in both the forward and reverse directions. In other words, in each cycle, the shutter torque applied to the drive gear in the clockwise and counterclockwise directions is equal in both directions (e.g., 30 Nm).

[0051] In another embodiment of the gear synchronization control, the shutter torque can be changed over a period of time; for example, changing from 2 Nm in the first rotational cycle of a series of clockwise and counterclockwise rotational cycles to 30 Nm in the last rotational cycle of the series. More specifically, the function RotationalShutter(a = 10, f = 2, g = 30, h = 3) causes the gear synchronization controller 78 to be configured to apply a shutter torque of 2 Nm to 30 Nm evenly distributed over 3 seconds at a frequency of 10 Hz. In a related embodiment, the change in force can vary in a non-uniform distribution within a series of clockwise and counterclockwise rotational cycles. The advantage of applying the force over time is that it can minimize the applied force required to drive the gear engagement between the shift teeth 10 and the gear teeth 12, thereby minimizing the likelihood of mechanical noise and mechanical "jitter".

[0052] In another embodiment, a disproportionate shutter torque can be considered for the direction of the driven gear (e.g., clockwise or counterclockwise relative to the axis A), for example, where the shutter torque applied to the drive gear is disproportionate in each clockwise and counterclockwise rotation cycle along the clockwise and counterclockwise directions, where a larger shutter torque is applied during the rotational movement in one of the clockwise or counterclockwise directions in each clockwise and counterclockwise rotation cycle, and a smaller shutter torque is applied during the rotational movement in the other of the clockwise and counterclockwise directions in each clockwise and counterclockwise rotation cycle. More specifically, the function RotationalShutter(a = 10, f = 30, i = 5) applies the larger shutter torque of 30 Nm, with the positive rotational force consistent with the forward (clockwise) rotation, and applies the smaller shutter torque of 5 Nm, with the negative rotational force consistent with the negative (counterclockwise) rotation, both applied at a frequency of 10 Hz. Knowing the required gear direction can be used to determine which part of the cycle benefits from a higher torque application level. For example, if the gear synchronization controller 78 determines that the driven gear 48 indicates forward (clockwise) movement, applying a higher torque in the positive (clockwise) rotational direction is consistent with the continued rotational direction after gear engagement. Applying a higher torque level in the negative direction, the function RotationalShutter(a = 10, f = 5, i = 30) is consistent with the continued reverse (counterclockwise) direction. By utilizing the disproportionate shutter torque, the likelihood of engagement between the respective teeth 10, 12 of the shift mechanism 66 and the driven gear 48 in the required travel direction is greater. This minimizes the "chatter" effect that the operator may encounter, i.e., the drive gear 46 moves in the opposite direction, the shift mechanism 64 engages with the driven gear 48, and then torque is applied in the required direction.

[0053] The extension of this embodiment can be seen in the example function RotationalShutter(a = 0, f = 0, i = 30). In this variant, the shutter torque of 30 Nm is applied in only one of the clockwise or counterclockwise directions of the drive gear 46 within each rotation cycle. For example, it is applied in the reverse (negative) direction only at a frequency of 10 Hz. For a further extension of this embodiment, the position of the driven gear 48 is used to determine the initial direction of the shutter torque application. Combining the initial rotation direction "e", the positive torque "f" and the negative torque "I" can be selected such that the larger shutter torque is applied in the clockwise or counterclockwise direction, thereby minimizing the rotational travel of the drive gear for keeping the shift teeth 10 and the gear teeth 12 in an aligned meshing relationship, so that the tapered edges are in contact. By minimizing the travel required to establish the meshing relationship between the shift mechanism 64 and the driven gear 48, the torque interruption is also minimized. Initiating the shutter at a high frequency in the opposite direction will increase the distance that the drive gear 46 (and the shutter mechanism 64 operably coupled thereto) rotates before the tapered edges contact; thus increasing the torque interruption time.

[0054] In an additional embodiment, the application of torque (positive or negative) can be changed within a calibratable time period. For example, the function RotationalShutter(a = 10, f = 2, g = 20, h = 3, i = 1, j = 5, k = 2) indicates that the drive gear 46 rotates forward and backward at a frequency of 10 Hz, with an initial positive torque of 2 Nm applied and a negative torque of 1 Nm applied. The positive torque will change from the initial 2 Nm to 20 Nm within 3 seconds, while the negative torque will increase from 1 Nm to 5 Nm within 2 seconds. Although the change in torque can be evenly distributed over a period of time, the extension of this embodiment will allow such a change to be disproportionate.

[0055] As an example combining the foregoing embodiments, when a zero-speed gear engagement is commanded (i.e., it is determined that the rotational speed increment between the drive gear 46 and the driven gear 48 is less than the predetermined speed increment (e.g., 20 rpm)), and it is known that the shift is into reverse gear, the function RotationalShutter(a = 2, b = 20, c = 3, d = 25, e = -1, f = 0, g = 0, h = 0, i = 5, j = 40, k = 3) is a function that commands the shutter frequency and torque pulses to change gradually, starting from the negative (reverse) direction, with a frequency of 2 Hz, a force of 5 Nm, a positive duty cycle of 25%, and a negative duty cycle of 75%. The frequency and the applied torque change from the initial negative torque pulse of 5 Nm to 40 Nm within 3 seconds, and the frequency becomes 20 Hz. By issuing such an instruction, the possibility of a blocked shift condition occurring when shifting into reverse gear is extremely small.

[0056] Since the lubricant-supported motor 30 can be controlled not only in torque mode but also in speed mode, the described embodiments related to torque applications can be extended to reference the use of engine speed instead of engine torque.

[0057] In another embodiment, a self-learning algorithm based on previous results and a plant model of the system is used to dynamically adjust the rotational baffle function parameters to continuously optimize gear synchronization during a zero-speed gear engagement command.

[0058] From an implementation perspective, an inverter in a power propulsion system controls the lubricant-supported motor 30. Thus, the inventors have naturally contributed to the placement of the controller 78 and the implementation of the associated rotational baffle function.

[0059] The above description of the embodiments is for illustrative and descriptive purposes only. It is not intended to be exhaustive or to limit the present disclosure. The individual elements or features of a particular embodiment are generally not limited to that particular embodiment but are interchangeable where applicable and can be used in a selected embodiment, even if not specifically shown or described. The same embodiment can also be varied in many ways. Such variations are not considered a departure from the present disclosure, and all such modifications are intended to be covered within the scope of the present disclosure.

[0060] For example, although described and illustrated above in connection with Figures 12 to 13 the shift teeth 10 disposed on the shift mechanism 64, the principles of the gear synchronization method and the associated gear synchronization controller 78 described herein can also be applied to the synchronous engagement of a driving gear tooth (represented as 10 in this example in Figures 1 to 3 with a driven gear tooth (represented as 12 in this example in Figures 1 to 3 in response to one of the driving gear 46 or the driven gear 48 sliding axially towards the other, for example, by a suitable shift mechanism 64 (such as a shift fork, etc.). At this time, a rotational baffle function is still applied to the driving gear 46 according to the aforementioned principle to reduce the possibility of jamming occurring between the meshing teeth 10', 12' of the driving gear 46 and the driven gear 48.

[0061] More specifically, similar to other devices, such as Figures 12 to 13As shown, the power transmission gear set 50 includes a driving gear 46 and a driven gear 48, each of the driving gear and the driven gear being rotatable about an axis A. The driving gear 46 has a plurality of driving gear teeth 10' concentrically arranged about the axis A, and the driven gear 48 has a plurality of driven gear teeth 12' also concentrically arranged about the axis A for meshing with the driving gear teeth 10'. A shift mechanism 64 can be operatively connected to one of the driving gear 46 or the driven gear 48 for sliding the operatively coupled driving gear 46 or driven gear 48 towards the other to establish a meshing relationship between the driving gear teeth 10' and the driven gear teeth 12', thereby transmitting torque from the driving gear 46 to the driven gear 48. A gear synchronization controller 78 is arranged to communicate with the driving gear 46, the driven gear 48 and the shift mechanism 64, and in response to detecting a gear meshing command, is configured to determine a rotational speed increment between the driving gear 46 and the driven gear 48 and to compare the rotational speed increment with a predetermined rotational speed increment (the aforementioned predetermined "zero or low" speed difference). In response to determining that the rotational speed increment is less than the predetermined rotational speed increment, the gear synchronization controller 48 is configured to apply a rotational blocking function to the driving gear 46 in accordance with the aforementioned gear synchronization principle, applying a series of clockwise and counterclockwise rotation cycles to the driving gear 46 during the simultaneous movement of the driving gear 46 or the driven gear 48 towards the other gear to prevent a jamming condition from occurring between the driving gear teeth 10' and the driven gear teeth 12'.

Claims

1. A power transmission gear set for an engine of a vehicle, characterized in that, The power transmission gear set includes: A driving gear and a driven gear, each of the driving gear and the driven gear being rotatable about an axis A; A shifting mechanism operatively coupled to one of the driving gear or the driven gear to rotate therewith; The other of the driving gear or the driven gear has a plurality of gear teeth concentrically arranged about the axis A; The shifting mechanism includes a plurality of shifting teeth concentrically arranged about the axis A, and in response to a gear engagement command, the plurality of shifting teeth are axially slidable relative to one of the driving gear or the driven gear operatively coupled therewith to urge the plurality of shifting teeth towards the plurality of gear teeth for finally setting the plurality of shifting teeth and the plurality of gear teeth in meshing relationship with each other, thereby transmitting torque from the driving gear to the driven gear; and A gear synchronization controller arranged to communicate with the driving gear, the driven gear and the shifting mechanism, and in response to detecting the gear engagement command, the gear synchronization controller is configured to: Determine a speed increment between a speed of the driving gear and a speed of the driven gear; Compare the speed increment with a predetermined speed increment; and In response to determining that the speed increment is less than the predetermined speed increment, initiate applying a rotational baffle function to the driving gear to simultaneously apply a series of clockwise and counterclockwise rotational cycles to the driving gear during the axial movement of the shifting mechanism to prevent a blocking condition of the power transmission gear set while establishing the meshing relationship between the plurality of shifting teeth and the plurality of gear teeth.

2. The power transmission gear set according to claim 1, wherein Each of the series of clockwise and counterclockwise rotational cycles has a rotational baffle frequency.

3. The power transmission gear set according to claim 2, characterized in that, The rotational baffle frequency of each clockwise and counterclockwise rotational cycle is adjusted from a first rotational cycle in the series of clockwise and counterclockwise rotational cycles to a last rotational cycle in the series of clockwise and counterclockwise rotational cycles.

4. The power transmission gear set according to claim 3, wherein, The rotational baffle frequency of each clockwise and counterclockwise rotational cycle increases sequentially from the first rotational cycle to the last rotational cycle.

5. The power transmission gear set according to claim 2, wherein, The rotational movement of the driving gear in each rotational cycle of the series of clockwise and counterclockwise rotational cycles in the clockwise and counterclockwise directions is equal and accounts for 50% of the engine baffle frequency.

6. The power transmission gear set according to claim 2, wherein, The rotational movement of the driving gear in each rotational cycle of the series of clockwise and counterclockwise rotational cycles in the clockwise and counterclockwise directions is disproportionate, wherein the rotational movement in the clockwise or counterclockwise direction in each rotational cycle is greater than 50% of the rotational baffle frequency, thereby determining a positive rotational frequency for each rotational cycle, and the rotational movement in the other of the clockwise or counterclockwise directions in each rotational cycle is less than 50% of the rotational baffle frequency, thereby determining a negative rotational frequency, the negative rotational frequency being equal to the rotational baffle frequency minus the positive rotational frequency.

7. The power transmission gear set according to claim 6, wherein The gear synchronization controller is further configured to detect a clockwise or counterclockwise direction of the drive gear in response to the detected gear engagement command, and to assign the positive rotation frequency to the corresponding clockwise or counterclockwise direction of the rotation cycle.

8. The power transmission gear set according to claim 1, wherein, The gear synchronization controller is further configured to determine a relative position of the shift teeth and the gear teeth and a shorter rotation direction of the drive gear to minimize the necessary stroke for establishing a meshing alignment between the shift teeth and the gear teeth, and to implement the shorter rotation direction as the initial clockwise or counterclockwise direction in each of the clockwise and counterclockwise rotation cycles of the series of clockwise and counterclockwise rotation cycles.

9. The power transmission gear set according to claim 2, wherein, The gear synchronization controller is further configured to initiate applying a detent torque to the drive gear during the rotational movement of the drive gear in the clockwise and counterclockwise directions in each of the clockwise and counterclockwise rotation cycles.

10. The power transmission gear set according to claim 9, characterized in that, The detent torque applied to the drive gear in the clockwise and counterclockwise directions in each of the clockwise and counterclockwise rotation cycles is equal.

11. The power transmission gear set according to claim 10, characterized in that, The detent torque applied to the drive gear in each of the clockwise and counterclockwise rotation cycles is adjusted from a first rotation cycle of the series of clockwise and counterclockwise rotation cycles to a last rotation cycle of the series of clockwise and counterclockwise rotation cycles.

12. The power transmission gear set according to claim 11, wherein, The detent torque applied to the drive gear in each of the clockwise and counterclockwise rotation cycles increases sequentially from the first rotation cycle to the last rotation cycle.

13. The power transmission gear set according to claim 9, wherein, The detent torque applied to the drive gear in the clockwise and counterclockwise directions in each of the clockwise and counterclockwise rotation cycles is disproportionate, wherein a larger detent torque is applied during the rotational movement of the drive gear in one of the clockwise or counterclockwise directions in each of the clockwise and counterclockwise rotation cycles, and a smaller detent torque is applied during the rotational movement of the drive gear in the other of the clockwise or counterclockwise directions in each of the clockwise and counterclockwise rotation cycles, and the smaller detent torque is less than the larger detent torque.

14. The power transmission gear set according to claim 13, wherein, The gear synchronization controller is further configured to detect a clockwise or counterclockwise direction of the drive gear in response to the detected gear engagement command, and to assign the larger detent torque to the corresponding clockwise or counterclockwise direction of the rotation cycle.

15. The power transmission gear set according to claim 13, wherein The gear synchronization controller is further configured to determine a relative position of the shift teeth and the gear teeth and a shorter rotation direction of the drive gear to minimize the necessary stroke for establishing a meshing alignment between the shift teeth and the gear teeth, and to assign the larger detent torque to the corresponding clockwise or counterclockwise direction of the rotation cycle that matches the shorter rotation direction.

16. The power transmission gear set according to claim 2, wherein, The gear synchronization controller is further configured to initiate the application of a detent torque during a rotational movement in one of the clockwise or counterclockwise directions during each clockwise and counterclockwise rotation cycle, but not to initiate the application of the detent torque during a rotational movement in the other of the clockwise or counterclockwise directions.

17. The power transmission gear set according to claim 1, wherein, The predetermined speed increment is 20 rpm.

18. The power transmission gear set according to claim 1, wherein, The engine is a wheel-end engine, and the drive gear is operably connected to the vehicle's tire.

19. The power transmission gear set according to claim 1, wherein, The engine is an electric motor, the electric motor including a stator and a rotor, the rotor extending along the axis A and rotatably disposed within the stator, and the drive gear being operably connected to the rotor of the electric motor.

20. A method for synchronizing a power transmission gear set, the power transmission gear set including a driving gear and a driven gear, each of the driving gear and the driven gear being rotatable about an axis A, and a shifting mechanism operatively coupled to one of the driving gear or the driven gear to rotate therewith, characterized in that, The method for synchronizing a power transmission gear set includes: at a gear synchronization controller: detecting a gear engagement command that causes the shift mechanism to axially slide relative to one of the operably coupled drive gear or driven gear and axially slide toward the other of the drive gear or driven gear to ultimately bring the shift teeth on the shift gear into an engaged relationship with the gear teeth on the other of the drive gear or driven gear; in response to detecting the gear engagement command, determining a speed increment between a speed of the drive gear and a speed of the driven gear; comparing the speed increment with a predetermined speed increment; and in response to determining that the speed increment is less than the predetermined speed increment, initiating the application of a rotational detent function to the drive gear to simultaneously apply a series of clockwise and counterclockwise rotation cycles to the drive gear during the axial movement of the shift mechanism to prevent a blocking condition of the power transmission gear set while establishing the engaged relationship between the plurality of shift teeth and the plurality of gear teeth.

Images