System and method for achieving a neutral state in an electric vehicle and enabling its towing.

Abstract

This document discloses a system for achieving a neutral state in an electric vehicle and enabling its towing. [Solution] System 100 comprises a lead screw assembly 107 and an operating function by a motor 108. The motor 108 displaces a nut 103 along the screw shaft, disengaging the split shaft 101 from the drivetrain and preventing the powertrain from rotating during towing. System 100 ensures that the vehicle remains in neutral and propels safe and efficient towing without causing damage to the drivetrain. Furthermore, towing the vehicle by disengaging the drivetrain via the lead screw assembly ensures safe towing operation when both batteries are depleted.

Description

Technical Field

[0001] In the following specification, the present invention and methods of implementing the present invention will be described in detail.

[0002] The present invention relates to the field of electric vehicle powertrains, and more particularly, to systems and methods for achieving a neutral state and enabling traction of an electric vehicle equipped with a single-speed gearbox. The present invention further relates to methods for achieving a neutral state of an electric vehicle and promoting its safe and efficient traction.

Background Art

[0003] An electric vehicle (EV) equipped with a single-speed gearbox typically lacks a neutral function or a power cut-off function, which poses a significant problem during towing operations. In the case of such vehicles, if the wheels rotate while being towed, the gearbox remains engaged and induces an electric current in the electric motor. This induced current can damage the motor's electronics and other electrical components. Additionally, if the wheels continue to rotate during towing, it can lead to wear and damage of the motor and transmission bearings as well as the engaged gear pair due to insufficient lubrication.

[0004] Existing solutions for achieving a neutral state in EVs often involve complex and costly mechanisms (e.g., clutch dampers or sliding sleeve systems operated electrically or hydraulically), which may not function effectively in scenarios where the vehicle's high-voltage (HV) battery and low-voltage (LV) battery are depleted. Furthermore, due to the complexity of these designs, integration challenges arise, particularly in compact EV architectures, and incorporating such solutions into existing vehicles is often not practical due to size, cost, and compatibility issues. Additionally, when manual intervention is required, it often requires excessive effort or specialized tools, reducing its practicality on the road or in emergency situations.

[0005] Several attempts have been made to address the challenges associated with achieving a neutral state in single-speed electric vehicles (EVs).

[0006] For example, Patent Document 1 (titled "Systems and methods for disengaging wheels") discloses a method and system for a wheel coupling mechanism. The wheel coupling mechanism includes a screw having a threaded portion, a block having a female threaded portion, and a coupler mechanically coupled to the screw. The coupler has a radially inner surface configured to be coupled to a drive shaft and a radially outer surface configured to be coupled to a spindle, and the screw is configured to engage the coupler with the drive shaft when actuated in a first direction and to disengage the coupler from the drive shaft when actuated in a second direction opposite to the first direction.

[0007] Patent Document 2 (titled "Mechanism for preventing power generation during towing of electric vehicle and electric vehicle towing method using the mechanism") discloses a mechanism for preventing power generation during towing of an electric vehicle. This mechanism includes a rod-shaped connecting member receiver configured such that a rod-shaped connecting member used during towing is inserted into the front or rear of the electric vehicle, and the inserted rod-shaped connecting member is locked in place; and a switch provided between the axle and the reduction gear, configured such that an insertion operation in which the rod-shaped connecting member is inserted into the rod-shaped connecting member receiver disconnects the axle and the reduction gear, and a removal operation in which the rod-shaped connecting member is removed from the rod-shaped connecting member receiver connects the axle and the reduction gear.

[0008] As a result, there is a need for a system that can achieve a neutral state without relying on active electrical and hydraulic components, especially when both high-voltage and low-voltage batteries are depleted, enabling the towing of an electric vehicle equipped with a single-speed gearbox, and allowing for manual intervention when necessary. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent Application Publication 2024 / 166043A1 [Patent Document 2] U.S. Patent Application Publication 2024 / 326585A1 Specification [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] This invention addresses the limitations of existing systems for achieving a neutral state in electric vehicles (EVs) equipped with a single-speed gearbox, particularly in situations where both the high-voltage and low-voltage batteries are depleted and the vehicle becomes inoperable. This invention discloses a system for achieving a neutral state in an electric vehicle (EV) so that it can be safely and efficiently towed when the vehicle becomes inoperable due to depletion of both high-voltage and low-voltage batteries. [Means for solving the problem]

[0011] The system comprises a split shaft consisting of two halves supported by bearings, and a lead screw assembly located inside the split shaft. The lead screw assembly comprises a screw shaft and a nut that moves along the split shaft via rotational action. The action is powered by a low-voltage motor or performed manually via a hexagonal nut. When the nut is displaced along the screw shaft, it disengages the differential gear pair from the gearbox shaft. This disengagement ensures that the wheels can rotate freely, enabling the towing of an electric vehicle without any mechanical resistance from drivetrain components (e.g., motor, transmission, or bearings).

[0012] Furthermore, this system provides a simple, cost-effective, and reliable solution by eliminating the need for active electrical or hydraulic systems, especially in situations where both high-voltage and low-voltage batteries are completely depleted. The system is compact and easily integrated into existing electric vehicles. In addition, it allows for manual intervention, providing flexibility in the event of battery failure or other operational problems, ensuring the safe towing or movement of the vehicle without damaging essential components.

[0013] Furthermore, the present invention discloses a method for achieving a neutral state in an electric vehicle equipped with a single-speed gearbox, thereby enabling its towing. This method involves disengaging a split shaft, composed of two halves supported by bearings, to allow the drivetrain to rotate freely. A lead screw assembly located within the split shaft is actuated, and the interaction between the screw shaft and the nut drives the disengagement process. Additionally, this method incorporates manual intervention to address battery failure or other operational problems, ensuring the safe towing or movement of the vehicle. This method effectively manages the neutral state of an electric vehicle, ensuring safe and efficient towing even when both high-voltage and low-voltage batteries are depleted, thus overcoming the limitations of current systems. [Brief explanation of the drawing]

[0014] [Figure 1] This diagram shows an exploded view of a system for achieving a neutral state in an automobile and enabling its towing, according to one embodiment of the present invention. [Figure 2] This shows the position of a nut in the driving state of an automobile, according to one embodiment of the present invention. [Figure 3] This shows the position of a nut in a towed state of an automobile, according to one embodiment of the present invention. [Figure 4] A flowchart illustrating a method for achieving a neutral state in an automobile and enabling its towing, according to an embodiment of the present invention, is shown. [Modes for carrying out the invention]

[0015] To more clearly and concisely describe and point out the subject matter of the claimed invention, the following definitions are provided for the specific terms used in the following written description.

[0016] The term "split shaft" refers to a shaft that is divided into two different parts, a first half and a second half, designed to engage or disengage for torque transmission between components.

[0017] The term "lead screw assembly" refers to a mechanism that includes a screw shaft and associated components and enables a nut to move linearly along its axis when the nut is rotated.

[0018] The term "haul" refers to the act of pulling or drawing an automobile, trailer, or other object by an automobile or mechanical device.

[0019] The term "gearbox shaft" refers to a central rotating component within a gearbox that transmits mechanical power between gears.

[0020] The term "drive train" refers to the components of an automobile that transmit power from an engine or motor to the wheels.

[0021] The term "power train" refers to an integrated system of components that generate power and deliver it to the wheels of an automobile. This term includes both the drive train and the prime mover.

[0022] The present invention discloses a system for achieving a neutral state in an electric vehicle equipped with a single-speed gearbox, which enables safe towing by disengaging drive train components. The system includes a split shaft having a nut configured to have restraint forces in the circumferential and radial directions to transmit torque during the driving state. A lead screw assembly displaces the nut to separate the first half of the split shaft from the second half, enabling the engagement of torque transmission between the two halves of the split shaft to be disengaged. The lead screw is operated by a motor powered by a low-voltage battery and can be manually operated via a hex nut when both batteries are depleted. Further, it is ensured that the vehicle can be towed without interference from the drive train by the gearbox shaft and differential gear pair.

[0023] FIG. 1 shows an exploded view of a system for achieving the neutral state of a vehicle and enabling its towing according to an embodiment of the present invention. The system (100) includes a split shaft (101) divided into two halves, namely a first half (101a) and a second half (101b), each half being supported by a bearing (102) to maintain the alignment of the split shaft (101) along its axis of rotation. The split shaft (101) promotes the transmission of torque during the driving state or normal operation of the vehicle, enables the disengagement of the drive train, and puts the vehicle in a neutral state for towing.

[0024] Furthermore, the system (100) includes a nut (103) positioned within the split shaft (101) to connect the first half (101a) and the second half (101b) of the split shaft (101). The nut (103) engages with both halves of the split shaft (101) to ensure torque transmission under normal driving conditions. The nut (103) includes a plurality of external engaging portions (104) which engage with corresponding internal engaging portions (105) of the first half (101a) and the second half (101b) of the split shaft (101) to ensure torque transmission. More specifically, the nut (103) comprises a plurality of external engaging portions (104), each configured to constrain both circumferentially and radially, which engage with corresponding internal engaging portions (105) further configured to constrain both circumferentially and radially on the first half (101a) and second half (101b) of the split shaft (101), enabling the transmission of torque during operation. A coil spring (106) further ensures that the nut (103) remains in the engaged torque-transmitting position during vehicle operation. In one embodiment of the present invention, the coil spring (106) is positioned on one side of the nut (103), with the shaft surface acting as a stopper on the opposite side to maintain the secure position of the nut (103) during vehicle operation.

[0025] Furthermore, the system (100) includes a lead screw assembly (107) housed within a split shaft (101) for displacing a nut (103) relative to a coil spring (106). More specifically, the lead screw assembly (107) displaces the nut (103) against the resistance of the coil spring (106). The lead screw assembly (107) also includes a screw shaft (114) which interacts with the nut (103) to move along the longitudinal direction of the screw shaft (114), disengaging the first half (101a) from the second half (101b) to facilitate the achievement of a neutral state for the vehicle, allowing traction without transmitting rotation from the wheels to the powertrain.

[0026] Furthermore, the system (100) includes a motor (108) powered by a low-voltage battery (109) and connected to a lead screw assembly (107). The motor (108) provides rotational motion to drive the lead screw assembly (107), which then moves a nut (103) to disengage the split shaft (101). The motor (107) ensures the automatic operation of the system (100) under normal conditions and allows for the disengagement of the drivetrain when necessary.

[0027] Furthermore, a hexagonal nut (110) is connected to the lead screw assembly (107) to facilitate manual operation of the system (100) when both the low-voltage battery (109) and the high-voltage battery (111) are depleted. Additionally, by manually rotating the hexagonal nut (110), the nut (103) can be displaced to achieve disengagement of the split shaft (101) for towing the vehicle. The hexagonal nut (110) is secured to the screw shaft (114) using a split pin (116) to ensure the stability of the system (100) during manual operation. More specifically, the motor shaft is extended to allow the assembly of the hexagonal nut (110), which is secured using a split pin (116). The hexagonal nut (110) provides a means for manually rotating the lead screw assembly (107) when both the low-voltage battery and the high-voltage battery are depleted, ensuring that the system (100) remains operational even without power.

[0028] Furthermore, the system (100) includes a differential gear pair (112) connected to a gearbox shaft (113), which disengages when a nut (103) is displaced. Displacement of the nut (103) disconnects the differential gear pair (112) from the gearbox shaft (113), allowing the vehicle's drivetrain to disengage from the wheels, thereby preventing wheel rotation from being transmitted to the powertrain and damaging the drivetrain when the vehicle is towed.

[0029] In one embodiment of the present invention, a screw shaft (114) provides the rotational motion required to displace a nut (103) along its longitudinal direction. The screw shaft (114) is equipped with a rectangular interface (115) that connects to a motor (108), which enables rotational control of the lead screw assembly (107) when the nut (103) is displaced.

[0030] In one embodiment of the present invention, the screw shaft (114) of the lead screw assembly (107) is completely axially constrained within the split shaft (101), allowing only rotational motion around its own axis. By axially constraining the screw shaft (114), axial displacement is eliminated, simplifying the mechanical design of the lead screw assembly (107). The configuration of the screw shaft (114) enables a compact design and optimizes spatial arrangement within the powertrain system. This feature further facilitates the integration of a simple rotary actuator to rotate the screw shaft (114) to displace the nut (103) and disengage the split shaft (101).

[0031] Figure 2 shows the position of a nut in the driving state of an automobile according to one embodiment of the present invention. In the driving state, the system (100) enables torque transmission from the prime mover to the wheels. The nut (103) is positioned such that its external engaging portion (104) engages with the internal engaging portions (105) of the first and second halves (101a, 101b) of the split shaft (101) to drive torque transmission during automobile operation. Furthermore, a coil spring (106) ensures that the nut (103) remains in the engaged position, maintaining effective torque transmission and ensuring efficient operation of the system (100). The split shaft (101) is supported by multiple bearings (102) to ensure proper alignment of the system (100) and prevent any misalignment or undesirable movement during automobile operation, so that the automobile can function under normal driving conditions with seamless torque transmission.

[0032] Figure 3 shows the position of a nut in the towed state of an automobile according to an embodiment of the present invention. In the towed state, the system (100) is configured to prevent the rotation of the wheels from being transmitted to the powertrain, thereby enabling safe towing of the automobile. The nut (103) moves linearly along the lead screw assembly (107), causing it to disengage from the split shaft (101). As the nut (103) moves, the external engagement portion (104) disengages from the internal engagement portion (105) of the split shaft (101), interrupting torque transmission to the wheels and preventing the rotation of the wheels from being transmitted to the powertrain during the towing process.

[0033] The lead screw assembly (107) is rotated by a motor (108) powered by a low-voltage battery (109), or manually rotated using a hexagonal nut (110) when both the high-voltage battery (111) and the low-voltage battery (109) are depleted. This manual operation ensures continued functionality even when the batteries are depleted or unavailable. In one embodiment of the present invention, the disengagement mechanism prevents the rotation of the wheels from being transmitted to the powertrain during towing, protects the components, and provides reliable towing for electric vehicles equipped with a single-speed gearbox.

[0034] Figure 4 shows a flowchart of a method for achieving a neutral state of an automobile and enabling its towing, according to an embodiment of the present invention. The method (400) includes, in step (401), operating a lead screw assembly using a motor powered by a low-voltage battery to displace a nut and disengage the split shaft when the high-voltage battery is depleted. The motor rotates the lead screw assembly, moving the nut linearly along the screw shaft, overcoming the force of the coil spring and disengaging the nut from the split shaft. Furthermore, in step (402), when both the low-voltage and high-voltage batteries are depleted, the hexagonal nut is manually rotated to displace the nut and disengage the split shaft. Furthermore, manual rotation of the hexagonal nut (110), which is secured by the split pin (116), provides an alternative mechanism for displacing the nut (103) and disengaging the split shaft (101). Disengaging the split shaft (101) separates the drivetrain from the wheels, prevents torque transmission, ensures the vehicle remains in a neutral state, and propels the vehicle's towing.

[0035] In one embodiment of the present invention, when the system (100) is powered by a high-voltage battery (111), the nut (103) ensures that the split shaft (101) remains engaged to transmit torque to the wheels. However, when the high-voltage battery (111) is depleted, the low-voltage battery (109) acts on the lead screw assembly (107) to displace the nut (103), disengaging the internal engagement portion (104) that restrains the split shaft (101) both circumferentially and radially, thereby preventing rotation of the powertrain and enabling safe towing of the vehicle without damaging the torque transmission mechanism.

[0036] In another embodiment, if both the low-voltage and high-voltage batteries (109, 111) are depleted, a hexagonal nut (110) connected to the lead screw assembly (107) can be manually rotated by the user to facilitate the same disengagement process, ensuring that the vehicle remains towable under any conditions and providing flexibility and reliability in emergency towing situations for the vehicle.

[0037] In one embodiment, in a scenario where power is transmitted via a single shaft without a specific disengagement mechanism, the system (100) is configured to allow power disconnection or to achieve a neutral state. This configuration allows for safe towing of the vehicle without the risk of damaging powertrain components. The system (100) is not limited to single-speed electric vehicles (EVs) but is designed to be adaptable to use with multi-speed gearboxes and various types of geartrains. The system (100) offers flexibility and can be adapted to various vehicle configurations. Furthermore, the system (100) simplifies the process of disengaging power flow to all wheels and achieving a neutral state using a single mechanism within the powertrain, ensuring that the vehicle is safely towed regardless of the specific gearbox type or transmission system.

[0038] While a general description of the present invention has been given so far, further understanding can be gained by referring to specific examples. These examples are provided solely for illustrative purposes and are not intended to be limiting unless otherwise specified.

[0039] Example 1: Demonstrative explanation of a system for enabling automobile towing. In a practical application of the present invention, the operation of a system enabling the towing of an electric vehicle (EV) in both automatic and manual modes under various battery depletion conditions is demonstrated. In towing mode, when the EV's high-voltage battery (111) is depleted, a motor (108) powered by the low-voltage battery (109) is activated, acting on the lead screw assembly (107) to displace the nut (103) and disengage the split shaft (101). When the motor (108) supplies power to the lead screw assembly (107), the nut (103) is displaced along the screw shaft (114). This displacement disengages the external engagement portion (104), which restrains the nut (103) both circumferentially and radially, from the internal engagement portion (105), which further restrains the split shaft (101) both circumferentially and radially, interrupting the connection between the drivetrain and the wheels. As a result, torque transmission to the wheels is stopped during towing. This disengagement separates the drivetrain components, ensuring safe towing without the risk of damaging the drivetrain. The system (100) seamlessly transitions the vehicle to a neutral position, eliminating the need for operator intervention and facilitating efficient and reliable towing.

[0040] During manual towing, the system (100) activates when both the high-voltage battery (111) and the low-voltage battery (109) are depleted. In this scenario, the operator / user manually rotates a hexagonal nut (110) connected to the lead screw assembly (107). By rotating the hexagonal nut (110), the lead screw assembly (107) is activated, displacing the nut (103) along the screw shaft (114). During this displacement, the external engagement portion (104) of the nut (103) disengages from the internal engagement portion (105) of the split shaft (101), effectively disconnecting the drivetrain from the wheels. This ensures that the drivetrain remains disengaged during manual towing, preventing wheel rotation from being transmitted to the powertrain and allowing the vehicle to be safely towed without causing damage to the powertrain.

[0041] This system offers several advantages in enhancing the functionality, efficiency, and reliability of its operation in ensuring safe towing. It promotes safe and efficient towing of electric vehicles in scenarios where the high-voltage battery (111) is depleted. Furthermore, by using a motor (108) powered by a low-voltage battery (109) to actuate the lead screw assembly (107), the nut (103) is displaced, disengaging the split shaft (101) and preventing wheel rotation from being transmitted to the powertrain, thus keeping the vehicle in a safe towing state. This automatic disengagement eliminates the need for manual intervention, providing convenience and ensuring the vehicle remains undriven during towing.

[0042] In scenarios where both the low-voltage and high-voltage batteries (109, 111) are depleted, the system (100) provides manual operation using a hexagonal nut (110). The system (100) further prevents wheel rotation from being transmitted to the powertrain during towing, protecting vehicle components (e.g., motor and drivetrain) from damage caused by unintended movement. [Explanation of Symbols]

[0043] 100 Systems 101 Split Shaft 101a First Hemisphere 101b The second half 102 Bearings 103 Nut 104 External engagement part 105 Internal engagement part 106 Coil spring 107 Lead Screw Assembly 108 Motor 109 Low-voltage battery 110 Hex nuts 111 High-voltage battery 112 Differential Gear Pair 113 Gearbox Shaft 114 Screw shaft 115 Rectangular Interface 116 Split Pins

Claims

1. A system for achieving a neutral state and towing of an automobile, wherein the system (100) a. A split shaft (101) divided into a first half (101a) and a second half (101b), wherein each half is supported by at least one bearing (102) to maintain the alignment of the split shaft (101), b. A nut (103) for connecting the first half (101a) and the second half (101b) of the split shaft (101) in order to transmit torque when in operation, i. Multiple external engaging portions (104) that engage with multiple internal engaging portions (105) of the split shaft (101), ii. To promote torque transmission, the nut (103) includes a coil spring (106) for fixing the nut (103) in the engaged position when it is in the driven state, c. A lead screw assembly (107) housed within the split shaft (101) for disengaging the nut (103) relative to the coil spring (106) to disengage the first half (101a) from the second half (101b), wherein in the disengaged state, the lead screw assembly (107) and the nut (103) remain stationary, ensuring that the vehicle's powertrain is completely separated from the rotating wheels during towing. d. A motor (108) powered by a low-voltage battery (109) for rotating the lead screw assembly (107) to displace the nut (103) from the engaged position to the disengaged position, e. A hexagonal nut (110) connected to the lead screw assembly (107) for manually pushing the displacement of the nut (103) when the low-voltage battery (109) and the high-voltage battery (111) are depleted, f. A differential gear pair (112) connected to a gearbox shaft (113), wherein the displacement of the nut (103) along the lead screw assembly (107) disengages the differential gear pair (112) from the gearbox shaft (113), allowing the vehicle to be towed without torque transmission via the split shaft (101). A system that includes this.

2. The system (100) according to claim 1, wherein the lead screw assembly (107) comprises a screw shaft (114) disposed within the split shaft (101), and the screw shaft (114) is constrained in the axial direction, allowing only rotational motion around its axis, thereby eliminating the need for axial displacement.

3. The system (100) according to claim 1, wherein the nut (103) is adapted to move along the screw shaft (114) when the motor (108) rotates or the hexagonal nut (110) is rotated manually.

4. The system (100) according to claim 1, wherein the screw shaft (114) is provided with a rectangular interface (115) for connecting to the motor (108) in order to promote rotational control of the lead screw assembly (107) when the nut (103) is displaced.

5. The system (100) according to claim 1, wherein the hexagonal nut (110) is fixed to the screw shaft (114) using the split pin (116) to allow manual displacement of the nut (103).

6. The system (100) according to claim 1, wherein the displacement of the nut (103) for disengaging the first half (101a) from the second half (101b) suppresses current induction in the motor (108) due to the rotation of the wheels when towing an electric vehicle.

7. A method for achieving a neutral state of an automobile and enabling its towing, wherein the method (400) a. When the high-voltage battery is depleted, the step of using a motor powered by a low-voltage battery to operate the lead screw assembly to displace the nut and disengage the split shaft, b. When both the low-voltage battery and the high-voltage battery are depleted, the procedure includes the step of manually rotating the hexagonal nut to displace the nut and disengage the split shaft, A method for disengaging the split shaft, which separates the drivetrain from the wheels, prevents torque transmission, ensures the vehicle remains in a neutral state, and propels the towing of the vehicle.

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