Drive disengagement method, mechanism and vehicle

Abstract

The present invention provides a drive disengagement method, mechanism, and vehicle. The drive disengagement method includes: obtaining a torque demand; determining a target position of a disengagement mechanism based on the torque demand; obtaining a position of a synchronizer connected to an intermediate shaft, the synchronizer connecting a drive motor and the disengagement mechanism; obtaining a current rotation angle of a disengagement motor that provides power to the disengagement mechanism; determining a current position of the disengagement mechanism based on the synchronizer position and the current rotation angle of the disengagement motor; rotating the disengagement motor based on the current position and target position of the disengagement mechanism; and adjusting the disengagement mechanism from the current position to the target position by adjusting the speed and torque output by the disengagement motor. The present invention enables a vehicle to achieve a four-wheel drive and two-wheel drive state conversion in different driving modes, different working conditions, and different environments, achieving both the power of four-wheel drive and the economy of real-time four-wheel drive.

Description

Technical Field

[0001] The present invention relates to the technical field of automobiles, and in particular to a drive disengagement method, a mechanism and an automobile. Background Art

[0002] As the core component of pure electric vehicles' power output, the powertrain system has a significant impact on their performance. Currently, two-wheel drive is the dominant system for pure electric vehicles, both domestically and internationally. As consumer demand for pure electric vehicle powertrain configurations diversifies, four-wheel drive systems are increasingly being adopted. Compared to traditional two-wheel drive pure electric vehicles, four-wheel drive systems offer significant improvements in power and operational stability, but still suffer from a disadvantage in terms of economic efficiency. Summary of the Invention

[0003] The purpose of the present invention is to provide a drive disengagement method and mechanism for a pure electric four-wheel drive vehicle, which has a lower structural cost and can meet the four-wheel drive power and achieve the two-wheel drive economy.

[0004] The present invention first provides a drive disengagement method for a pure electric four-wheel drive vehicle, including: obtaining a torque demand; determining a target position of a disengagement mechanism based on the torque demand; obtaining a position of a synchronizer connected to an intermediate shaft, wherein the synchronizer connects a drive motor and the disengagement mechanism; obtaining a current rotation angle of a disengagement motor that provides power to the disengagement mechanism; determining a current position of the disengagement mechanism based on the synchronizer position and the current rotation angle of the disengagement motor; rotating the disengagement motor based on the current position and the target position of the disengagement mechanism; and adjusting the disengagement mechanism from the current position to the target position by adjusting the speed and torque output by the disengagement motor.

[0005] Furthermore, the step of adjusting the disengaging mechanism from the current position to the target position by adjusting the speed and torque output by the disengaging motor includes: reducing the speed output by the disengaging motor in multiple stages and amplifying the output torque in multiple stages; and adjusting the disengaging mechanism from the current position to the target position by adjusting the speed after the multi-stage reduction and the torque after the multi-stage amplification.

[0006] Furthermore, before the step of determining the current position of the disengaging mechanism based on the synchronizer position and the current rotation angle of the disengaging motor, the step further includes: obtaining the synchronizer position based on a position sensor provided in the disengaging mechanism and connected to the synchronizer.

[0007] The present invention further provides a drive disengagement mechanism for a pure electric four-wheel drive vehicle, comprising: a disengagement motor, which obtains a torque demand signal from a vehicle controller and outputs a disengagement torque; a reduction mechanism, comprising a multi-stage reducer, the input end of the multi-stage reducer being connected to the disengagement motor, and the output end being connected to a disengagement component; and a disengagement component, the input end of which is connected to the reduction mechanism, and the output end of which is connected to a synchronizer assembly, so that the synchronizer assembly outputs or cuts off power according to the torque demand.

[0008] Furthermore, the multi-stage reducer includes a first-stage reducer and a second-stage reducer connected in series, and the input end of the first-stage reducer is connected to the disengagement motor; the multi-stage reducer reduces the speed output by the disengagement motor, and amplifies the torque output by the disengagement motor and transmits it to the disengagement component.

[0009] Furthermore, the disengagement assembly includes a shift drum and a shift fork. When the shift drum rotates, it pushes the shift fork to move, thereby driving the synchronizer ring on the synchronizer assembly to move left and right, thereby connecting or disconnecting the separated intermediate shaft of the synchronizer assembly.

[0010] Furthermore, a position sensor is provided on the shift fork, and the position sensor monitors the left and right movement of the shift fork through a permanent magnet.

[0011] The present invention also provides a disengagement method for a driving disengagement mechanism, comprising: a controller performs operating condition calculation based on the current operating state of the vehicle and information from vehicle sensor actuators, and calculates the target position of the current disengagement component; the controller determines the actual position of the disengagement component; when the actual position of the disengagement component is consistent with the target position, the current state of the disengagement component is maintained, otherwise the disengagement motor is controlled to operate; and, after reducing the output speed of the disengagement motor and amplifying the output torque, the disengagement component is started.

[0012] Furthermore, the controller determines the actual position of the disengagement component based on the position sensor signal and the disengagement motor rotation angle information obtained in real time.

[0013] The present invention finally provides a car having any one of the above-mentioned drive disengagement mechanisms.

[0014] The present invention enables the vehicle to achieve conversion between four-wheel drive and two-wheel drive in different driving modes, different working conditions and different environments, and can achieve both the power of four-wheel drive and the economy of real-time four-wheel drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 4 is a flow chart of the drive disengagement method according to the first embodiment of the present invention.

[0016] Figure 2 It is a partial flow chart of the drive disengagement method according to the first embodiment of the present invention.

[0017] Figure 3 FIG. 2 is a simple block diagram of a drive disengagement mechanism according to a second embodiment of the present invention.

[0018] Figure 4 1 is a detailed block diagram of a drive disengagement mechanism according to a second embodiment of the present invention.

[0019] Figure 5 It is a schematic diagram of the specific structure of the driving disengagement mechanism of the second embodiment of the present invention.

[0020] Figure 6 4 is a flow chart of a drive disengagement method according to a third embodiment of the present invention.

[0021] Figure 7 4 is a detailed flow chart of the drive disengagement method according to the third embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] The terms "mounted," "connected," "connect," and "fixed" in the specification and claims of the present invention should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; mechanical or electrical connections, or communication; direct or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] First embodiment

[0025] See also Figure 1 A preferred embodiment of the present invention provides a drive disengagement method for a pure electric four-wheel drive vehicle, comprising:

[0026] Step S2, obtaining torque demand;

[0027] The present invention notes that for pure electric four-wheel drive models, in some working conditions, such as coasting, deceleration, low load, and urban congested road conditions, the vehicle can operate in two-wheel drive mode to meet customer driving needs, and the two-wheel drive mode is generally the rear-wheel drive mode. In some working conditions, such as off-roading, climbing steep slopes, accelerating with a large throttle, and driving on icy and snowy roads, the four-wheel drive mode is required. When driving in two-wheel drive mode, the front drive motor rotor is reversely dragged by the front wheels and operates in zero-torque mode. There is the uneconomical consumption of reverse drag friction energy and zero-torque control consuming electrical energy. When working at zero torque, a back electromotive force will be generated to damage the controller. At the same time, zero-torque operation may bring about drivability problems. For such working conditions, the technical solution provided by the present invention can avoid the aforementioned problems.

[0028] The vehicle torque demand can be obtained through vehicle operating status information, such as vehicle position information, vehicle speed, engine operating status, operating status information of each vehicle component, etc., and ADAS status data information, etc. In this way, the torque demand can be obtained in a timely manner by making a comprehensive judgment based on the vehicle information;

[0029] Step S4, determining a target position of the disengagement mechanism based on the torque requirement;

[0030] When calculating operating conditions based on vehicle sensor and actuator information, factors such as the vehicle's drivability, power, and safety can be considered. The operating condition can include whether it is four-wheel drive or two-wheel drive, or whether certain wheels are used as drive wheels. The operating condition calculation determines the disengagement or combination requirements and the target position of the disengagement mechanism.

[0031] Step S6, obtaining the position of the synchronizer connected to the intermediate shaft, the synchronizer connecting the drive motor and the disengagement mechanism;

[0032] The intermediate shaft is connected to the drive motor, and the intermediate shaft transmits or cuts off the power transmitted to the drive motor by separating and connecting the left and right sections;

[0033] Step S8, obtaining the current rotation angle of the disengagement motor that provides power to the disengagement mechanism;

[0034] The motor can be disengaged to control whether to output power by turning left or right;

[0035] Step S10, determining the current position of the disengagement mechanism based on the synchronizer position and the current rotation angle of the disengagement motor;

[0036] Step S12, rotating the disengagement motor based on the current position and the target position of the disengagement mechanism;

[0037] The current position is, for example, a disengagement mechanism to make the vehicle in a four-wheel drive state; or a disengagement mechanism to make the vehicle in a two-wheel drive state; the target state is, for example, a two-wheel drive state or a four-wheel drive state;

[0038] Step S14, adjusting the disengagement mechanism from the current position to the target position by adjusting the speed and torque output by the disengagement motor;

[0039] Specifically, see Figure 2 The step of adjusting the disengagement mechanism from the current position to the target position by increasing the speed and torque output by the disengagement motor, i.e., step S14, may include:

[0040] Step S142, reducing the output speed of the disconnecting motor in multiple stages and amplifying the output torque in multiple stages;

[0041] Step S144, using the multi-stage reduced speed and the multi-stage amplified torque to adjust the disengagement mechanism from the current position to the target position.

[0042] Before the step of determining the current position of the disengaging mechanism based on the synchronizer position and the current rotation angle of the disengaging motor, that is, before step S10, the method further includes the following steps:

[0043] In step S9 , the synchronizer position is acquired based on a position sensor provided in the disengagement mechanism and connected to the synchronizer.

[0044] Second embodiment

[0045] See also Figure 3 . A preferred embodiment 2 of the present invention provides a drive disengagement mechanism for a pure electric four-wheel drive vehicle, including a disengagement motor 20, a reduction mechanism 40 and a disengagement assembly 60. The disengagement motor 20 obtains a torque demand signal from the controller 10 and outputs a disengagement torque. The controller 10 can be a whole vehicle controller. The reduction mechanism 40 includes a multi-stage reducer, the input end of the multi-stage reducer is connected to the disengagement motor 20, and the output end is connected to the disengagement assembly 60. The input end of the disengagement assembly 60 is connected to the reduction mechanism 40, and the output end is connected to the synchronizer assembly 50, so that the synchronizer assembly 50 outputs or cuts off power according to the torque demand.

[0046] See also Figure 4 In this embodiment, the multi-stage reducer includes a first-stage reducer 42 and a second-stage reducer 44 connected in series. The input end of the first-stage reducer 42 is connected to the disconnect motor 20. The two-stage reducer can make each stage smaller, thus occupying less space and making better use of the space inside the vehicle.

[0047] The disengagement motor 20 is preferably a BLDC (Brushless Direct Current) motor. The disengagement assembly 60 may include a shift drum 62 and a shift fork 64. Through grooves on the shift drum 62, the shift drum 62 rotates, pushing the shift fork 64 to move, thereby driving the synchronizer ring 52 on the synchronizer assembly 50 to move left and right, engaging or disengaging the intermediate shaft 72 of the synchronizer assembly 50, thereby disengaging and engaging the synchronizer assembly 50, cutting off power to the wheels 74, or transmitting power to the wheels 74. The disengagement assembly 60 may also be implemented using other methods, such as hydraulic clutches, ECVTs, and other transmission designs, which are not detailed here.

[0048] A position sensor 66 is mounted on the shift fork 64. This sensor monitors the left and right movement of the shift fork 64 via a permanent magnet and provides feedback to the controller 10 on the position of the disengagement assembly 60. Similarly, the disengagement motor 20 not only serves as the actuator for the disengagement mechanism but also, via its internal Hall effect sensor, provides feedback on the rotation angle to the controller 10, thereby calculating the disengagement mechanism's status. The controller 10 can cross-check the information from the position sensor 66 with that from the disengagement motor 20 to confirm the accurate position of the disengagement mechanism. When the position information of the disengagement mechanism reflected by the position sensor 66 and the disengagement motor 20 is the same, this position information is determined to be the current position of the disengagement mechanism. For example, the current position may be when the disengagement motor is rotated clockwise by a set angle, the shift fork connects the two ends of the intermediate shaft via the synchronizer, and the vehicle is in four-wheel drive mode; or when the disengagement motor is rotated counterclockwise by a set angle, the shift fork disconnects the two ends of the intermediate shaft via the synchronizer, and the vehicle is in two-wheel drive mode.

[0049] The multi-stage speed reducer transmits BLDC power, reducing the speed of the disconnect motor 20 and amplifying the torque before transmitting it to the disconnect assembly 60. After deceleration, the disconnect motor 20 proportionally reduces the BLDC speed, which already has high speed control accuracy, further improving speed control accuracy. At the same time, torque is amplified, enabling low-torque control and reducing BLDC costs.

[0050] See also Figure 5In a specific embodiment, the above technical solution can disengage the front drive in a pure electric four-wheel drive vehicle, so that the front drive motor is not reversely dragged and the rear drive is driven separately, avoiding the economic and drivability problems caused by the reverse drag of the front drive motor rotor and zero torque control. The disengagement motor 20 adopts a BLDC small motor, and the multi-stage reducer includes a first-stage reducer 42 and a second-stage reducer 44. The power output by the BLDC small motor is transmitted to the shift drum 62, and a permanent magnet bar of a position sensor 66 is provided on the shift fork 64. The shift fork 64 is also connected to the synchronizer assembly 50. The drive motor 30 is a front drive motor, and the wheels are front drive wheels. The drive motor 30 transmits power to the front drive wheels 74 through the synchronizer assembly 50 and the intermediate shaft 72.

[0051] See again Figure 5 When the disengagement mechanism is in the disengaged state, if engagement is required, the BLDC motor is controlled to rotate forward. This BLDC motor drives the shift drum forward by disengaging the first and second stage reducers. The shift drum's rotation pushes the shift fork to the right, which in turn drives the synchronizer ring on the synchronizer assembly to the right, connecting the left and right ends of the synchronizer assembly's separated intermediate shaft. This allows power from the front drive motor's input shaft to be transmitted, effectively engaging the disengagement mechanism.

[0052] Third embodiment

[0053] See also Figure 6 and Figure 7 This embodiment provides a control method or a disengagement method for a drive disengagement mechanism of a pure electric four-wheel drive vehicle, including:

[0054] Step Sb, the controller performs working condition calculation based on the current operating state of the vehicle and information from the vehicle sensors and actuators, and calculates the target position or target state of the current disengaged component;

[0055] When the vehicle is driving, the current operating status of the vehicle, such as vehicle location information, vehicle speed, engine operating status, operating status information of each vehicle component, etc., can also be ADAS status data information, so that timely prompts can be given through comprehensive judgment of vehicle information;

[0056] When calculating operating conditions based on vehicle sensor and actuator information, factors such as the vehicle's drivability, power, and safety can be considered. The operating conditions can include whether the vehicle is four-wheel drive or two-wheel drive, or whether certain wheels are used as drive wheels. The operating condition calculation can be used to determine whether the vehicle is disconnected or engaged.

[0057] Step Sd, the controller determines the actual position of the disengaged component;

[0058] The controller 10 determines the actual position of the disengagement assembly 60 based on the real-time acquired position sensor signal and the disengagement motor rotation angle information. The disengagement assembly 60 includes a shift drum 62 and a shift fork 64. When the disengagement motor 20 activates the disengagement assembly 60, the shift drum 62 rotates, pushing the shift fork 64 to move, thereby driving the synchronizer ring 52 on the synchronizer assembly 50 to move left and right, thereby engaging or disengaging the left and right ends of the intermediate shaft 72 connected to the synchronizer assembly 50.

[0059] Step Sf, when the actual position of the disengagement component is consistent with the target position, the current state of the disengagement component is maintained; otherwise, the disengagement motor is controlled to operate;

[0060] Before the controller disengages the motor, it must ensure that the speed and torque difference of the shafts at both ends of the synchronizer are within a certain range;

[0061] Step Sh, reducing the speed of the disengagement motor output and amplifying the output torque, and then starting the disengagement component;

[0062] The disengagement motor drives the shift drum through the first and second stage reducers, thereby driving the shift fork to move;

[0063] As the shift fork 64 moves, the position sensor 66 monitors the position of the synchronizer and, in turn, the position of the disengagement mechanism by monitoring the permanent magnet bar 662, which operates synchronously with the shift fork 64. This information is then fed back to the controller 10 in real time. During BLDC operation, the BLDC rotation angle is fed back in real time to determine the position of the disengagement mechanism, and this information is also fed back in real time.

[0064] In summary, the present invention recognizes that under certain operating conditions, such as coasting deceleration, the front drive of a four-wheel drive vehicle may be dragged backward, potentially leading to issues with energy consumption, zero-torque control, and drivability. Therefore, a motor disengagement method and mechanism have been designed to disengage a drive motor, such as a front-drive motor or a rear-drive motor. This structure, combined with a logic control method, controls the rotation of a small BLDC motor to drive the shift drum, thereby disengaging and engaging the synchronizer, achieving disengagement and engagement between the motor and the axle. This technical solution utilizes first- and second-stage reduction gears to reduce the BLDC's inherently high speed control precision, further improving speed control accuracy. Simultaneously, torque is amplified, enabling low-torque control and reducing BLDC costs. Through a comprehensive set of disengagement and / or control methods, this technical solution enables the vehicle to transition between four-wheel drive and two-wheel drive modes in different driving modes, operating conditions, and environments, achieving both the power and economy of four-wheel drive.

[0065] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A drive disengagement method for a pure electric four-wheel drive vehicle, characterized in that: include: Get torque demand; determining a target position of the disengagement mechanism based on the torque demand; acquiring a position of a synchronizer connected to an intermediate shaft, wherein the synchronizer connects a drive motor and the disengagement mechanism; obtaining a current rotation angle of a disengagement motor that provides power to the disengagement mechanism; determining a current position of the disengagement mechanism based on the synchronizer position and the current rotation angle of the disengagement motor; rotating the disengagement motor based on the current position and the target position of the disengagement mechanism; as well as The disengagement motor outputs a rotational speed and a torque to adjust the disengagement mechanism from a current position to a target position; The step of adjusting the disengagement mechanism from a current position to a target position by increasing the speed and torque output by the disengagement motor comprises: The rotation speed output by the disconnecting motor is reduced in multiple stages and the output torque is amplified in multiple stages; The speed after multi-stage reduction and the torque after multi-stage amplification are used to adjust the disengagement mechanism from the current position to the target position.

2. The drive disengagement method according to claim 1, characterized in that: Before the step of determining the current position of the disengaging mechanism based on the synchronizer position and the current rotation angle of the disengaging motor, the method further includes the following steps: A synchronizer position is acquired based on a position sensor provided at the disengagement mechanism and connected to the synchronizer.

3. A drive disengagement mechanism according to the drive disengagement method according to any one of claims 1 to 2, used in a pure electric four-wheel drive vehicle, characterized in that: include: The motor (20) is disengaged, and a torque demand signal is obtained from the vehicle controller, and a disengagement torque is output; A speed reduction mechanism (40) comprising a multi-stage speed reducer, wherein an input end of the multi-stage speed reducer is connected to the disengagement motor (20), and an output end is connected to the disengagement assembly (60); as well as A disengaging component (60) has an input end connected to the speed reduction mechanism (40) and an output end connected to the synchronizer assembly (50), and causes the synchronizer assembly (50) to output or cut off power according to the torque requirement.

4. The drive disengagement mechanism according to claim 3, wherein: The multi-stage reducer comprises a first-stage reducer (42) and a second-stage reducer (44) connected in series, wherein the input end of the first-stage reducer (42) is connected to the disengagement motor (20); The multi-stage reducer reduces the rotational speed output by the disengagement motor (20), amplifies the torque output by the disengagement motor (20), and transmits the amplified torque to the disengagement component (60).

5. The drive disengagement mechanism according to claim 3, wherein: The disengagement assembly (60) includes a shift drum (62) and a shift fork (64). When the shift drum (62) rotates, it pushes the shift fork (64) to move, thereby driving the synchronizer ring (52) on the synchronizer assembly (50) to move left and right, thereby connecting or separating the left and right ends of the intermediate shaft (72) connected to the synchronizer assembly (50).

6. The drive disengagement mechanism according to claim 5, wherein: A position sensor (66) is provided on the shift fork (64), and the position sensor (66) monitors the left and right movement of the shift fork (64) through a permanent magnet.

7. A control method for a drive disengagement mechanism according to any one of claims 3 to 6, characterized in that: include: The controller calculates the working condition based on the current operating state of the vehicle and the information from the vehicle sensors and actuators, and calculates the target position of the current disengaged component; The controller determines the actual position of the disengagement component; When the actual position of the disengaging component is consistent with the target position, the current state of the disengaging component is maintained; otherwise, the disengaging motor is controlled to operate; as well as After the rotation speed output by the disengagement motor is reduced and the output torque is amplified, the disengagement component is started.

8. The control method of the drive disengagement mechanism according to claim 7, characterized in that: The controller determines the actual position of the disengagement component according to the position sensor signal and the disengagement motor rotation angle information obtained in real time.

9. An automobile, characterized in that: The automobile comprises the drive disengagement mechanism according to any one of claims 3 to 6.

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