Electric control differential lock for full-decoupling four-wheel-drive system, control method and vehicle

Abstract

The invention discloses an electric control differential lock for a full-decoupling four-wheel drive system, a control method and a vehicle, and relates to the technical field of vehicle transmission. The electric control differential lock comprises a planetary gear set, a clutch, a two-stage linkage gear, a driving mechanism and a sealing shell; the four planetary gear sets are divided into two sets which are arranged in a bilateral symmetry mode, and sun gears of the two planetary gear sets in each set are coaxially and fixedly connected through a first-stage linkage gear. A planet carrier of each planetary gear set is used for being connected with an output shaft of a motor. Each clutch is correspondingly arranged at the large gear ring of one planetary gear set and is used for locking or releasing the corresponding large gear ring; the secondary linkage gear is movably arranged; the driving mechanism drives the secondary linkage gear to move; by controlling the clutch and the two-stage linkage gear, switching among an all-wheel independent mode, a single-side synchronous mode, an all-wheel synchronous mode and the like can be achieved, on the premise that independent control of the motor is not damaged, distribution of power according to needs is achieved, and the problem of power loss during wheel slipping is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle transmission technology, in particular to an electric control differential lock for a full decoupling four-wheel drive system, a control method and a vehicle. BACKGROUND

[0002] With the rapid development of intelligent chassis and automatic driving technology, four-wheel independent drive (i.e. full decoupling four-motor four-wheel drive system) gradually becomes one of the mainstream driving forms of intelligent vehicles due to its flexible motion control, simple structure layout, efficient energy distribution and other advantages. In this system, four wheels are driven by independent motors, and the central differential, transmission shaft and other coupling components in the traditional mechanical transmission are cancelled, realizing complete independent control of the rotation speed and torque of each wheel, which can support advanced motion control functions such as tank steering and accurate distribution of yaw moment.

[0003] However, when driving on unpaved roads (such as mud, sand, snow, etc.), the full decoupling four-wheel drive system faces significant challenges: when some wheels slip or float due to insufficient road adhesion, the lack of mechanical connection between the motors makes it impossible to effectively transmit power to the wheels with adhesion, resulting in a serious loss of vehicle driving force and difficulty in getting out of trouble.

[0004] Traditional four-wheel drive systems usually use mechanical differential locks or limited slip differentials to redistribute power between wheels, but these solutions rely on mechanical transmission shafts as power transmission carriers and cannot be applied to full decoupling architectures without mechanical connections between motors. If a traditional differential lock structure is forcibly introduced into a full decoupling system, it will destroy the independent control ability of each motor and cause problems such as complex structure, delayed response, large size, etc.

[0005] Therefore, there is an urgent need for an electric control differential device that can maintain the independent control characteristics of four motors and achieve power coupling and redistribution in low adhesion conditions to improve the passability and reliability of the full decoupling four-wheel drive system in complex road environments. SUMMARY

[0006] The purpose of the present application is to provide an electric control differential lock for a full decoupling four-wheel drive system, a control method and a vehicle to solve the problem that the full decoupling four-wheel drive system in the prior art cannot effectively transmit power to wheels with adhesion in low adhesion road conditions, and the traditional mechanical differential lock cannot be compatible with it, so that the vehicle can retain the advantages of four-wheel independent drive while obtaining strong off-road escape ability.

[0007] To achieve the above purpose, the present application provides the following solutions: The application provides an electrically controlled differential lock for a full decoupling four-wheel drive system, comprising four planetary gear sets, four clutches, a secondary linkage gear, a driving mechanism and a sealed housing; the four planetary gear sets are divided into two groups symmetrically arranged on the left and right sides, and the sun gears of the two planetary gear sets in each group are coaxially fixedly connected through a primary linkage gear; the planet carrier of each planetary gear set is used for connecting the output shaft of an independent motor; each clutch is arranged at the large gear ring of a planetary gear set, and is used for selectively locking or releasing the corresponding large gear ring; the secondary linkage gear is movably arranged; the driving mechanism is used for driving the secondary linkage gear to move, so that the secondary linkage gear has at least two working positions: a first position, at most meshing with one primary linkage gear; and a second position, simultaneously meshing with two primary linkage gears; and the sealed housing is used for encapsulating all the planetary gear sets, clutches, primary linkage gears and secondary linkage gears.

[0008] Preferably, the clutch is an electromagnetic clutch.

[0009] Preferably, the driving mechanism is a push rod motor or a linear servo motor, and the output end of the driving mechanism is connected with the rotating shaft of the secondary linkage gear through a connecting rod.

[0010] Preferably, the rotating shaft of the secondary linkage gear is constrained in a guide groove in the sealed housing, and the driving mechanism drives the rotating shaft to move along the guide groove, so as to realize the position switching of the secondary linkage gear.

[0011] Preferably, the profile line of the guide groove is arc-shaped, and is coaxial with one of the primary linkage gears; so that the secondary linkage gear is always in meshing state with one of the primary linkage gears.

[0012] Preferably, the electrically controlled differential lock is configured to realize multiple working modes by controlling the clutches and the driving mechanism, including: full-wheel independent mode, all the clutches release all the large gear rings, and the secondary linkage gear is in the first position; single-side synchronous mode, the two clutches on the same side lock the corresponding two large gear rings, and the secondary linkage gear is in the first position; full-wheel synchronous mode, all the clutches lock all the large gear rings, and the secondary linkage gear is in the second position.

[0013] Preferably, the protection level of the sealed housing is not less than IP68.

[0014] Preferably, four shaft holes are arranged on the sealed housing, and the output shafts of the motors are inserted from outside the sealed housing to inside the sealed housing through the shaft holes.

[0015] The application also provides a vehicle comprising the electrically controlled differential lock as described above.

[0016] The application also provides a method for controlling the electrically controlled differential lock as described above, comprising: acquiring wheel speed signals and / or wheel slip signals of the vehicle; controlling the target clutch to lock or release the corresponding large gear ring according to the signals; controlling the driving mechanism to drive the secondary linkage gear to move to a target position according to the power coupling demand.

[0017] The application has the following technical effects relative to the prior art: The application can switch between full-wheel independent, single-side synchronization, full-wheel synchronization and other modes by controlling the clutch and the secondary linkage gear, realizes on-demand distribution of power under the premise of not damaging the independent control of the motor, and fundamentally solves the problem of power loss when the wheels slip. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description only constitute some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 The structural schematic diagram of the electrically controlled differential lock for full-decoupling four-wheel drive system provided by the application is shown in the figure. In the figure: 1-sealing housing; 2-clutch fixing screw; 3-clutch; 4-clutch rotor; 5-large gear ring; 6-planetary gear set; 7-primary linkage gear; 8-output shaft; 9-guide groove; 10-push rod motor; 11-connecting rod; 12-secondary linkage gear; 13-shaft hole; 14-sun gear. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments only constitute some of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0021] The application aims to provide an electric control differential lock for a full decoupling four-wheel drive system, a control method and a vehicle, so as to solve the problem that the full decoupling four-wheel drive system in the prior art cannot effectively transmit power to the wheels with adhesion on low adhesion road surface, and the traditional mechanical differential lock cannot be compatible with the full decoupling four-wheel drive system, so that the vehicle can obtain strong off-road escape ability while retaining the advantages of four-wheel independent drive.

[0022] In order to make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the application will be further described in detail below in combination with the drawings and specific embodiments.

[0023] The embodiments of the application will be described below in combination with Figure 1 .

[0024] Embodiment one The application provides an electric control differential lock for a full decoupling four-wheel drive system, which comprises four planetary gear sets 6, four clutches 3, a secondary linkage gear 12, a driving mechanism and a sealed housing 1; the four planetary gear sets 6 are divided into two groups symmetrically arranged on the left and right, and the sun gears 14 of the two planetary gear sets 6 in each group are coaxially fixedly connected through a primary linkage gear 7; the planet carrier of each planetary gear set 6 is used for connecting the output shaft 8 of an independent motor; each clutch 3 is correspondingly arranged at the large gear ring 5 of a planetary gear set 6 and is used for selectively locking or releasing the corresponding large gear ring 5; the secondary linkage gear 12 is movably arranged; the driving mechanism is used for driving the secondary linkage gear 12 to move, so that the secondary linkage gear 12 has at least two working positions: a first position, which is at most engaged with one primary linkage gear 7; and a second position, which is simultaneously engaged with two primary linkage gears 7; and the sealed housing 1 is used for encapsulating all the planetary gear sets 6, clutches 3, primary linkage gears 7 and secondary linkage gears 12.

[0025] The fundamental problem of the full decoupling system is that there is no mechanical connection between the four power sources (motors), which leads to the inability to transmit power across the wheels. The present solution introduces four independent planetary gear sets 6 as the basic interface, with each interface connecting one motor, first ensuring the independence of each motor in controlling its own wheels. A clutch 3 is provided at the ring gear 5 of each planetary gear set 6, and its locking or releasing directly determines the transmission state of the planetary gear set 6: when the clutch 3 is released, the ring gear 5 is free, and the planetary gear set 6 allows a speed difference between the sun gear 14 and the planet carrier, corresponding to independent wheel drive; when the clutch 3 is locked, the ring gear 5 is fixed, and the planetary gear set 6 becomes a fixed-ratio reducer, with the sun gear 14 speed being forcibly linked to the planet carrier speed. Through the coaxially fixed first-level linkage gear 7, the sun gears 14 (i.e., motor output ends) of the two wheels on the same side can be rigidly connected first, and then by selectively locking the two clutches 3 on the same side, the rotational speeds of the two wheels on the same side can be forcibly synchronized, achieving single-side power coupling. Further, through the movable second-level linkage gear 12, when it is simultaneously meshed with the first-level linkage gears 7 on the left and right sides, the motor output ends on the left and right sides are also connected. At this time, if all four clutches 3 are locked, the ring gears 5 of all four planetary gear sets 6 are fixed, and all sun gears 14 are rigidly connected through the first- and second-level linkage gears 12, ultimately forcing the rotational speeds of the four planet carriers (i.e., four wheels) to be forcibly synchronized. Therefore, by controlling the states of the clutches 3 and the position of the second-level linkage gear 12, the structure can seamlessly switch between various modes such as "full-wheel independence", "single-side synchronization", and "full-wheel synchronization", achieving on-demand coupling and redistribution of power without disrupting the original motor-independent control architecture, and fundamentally solving the problem of power loss when a single or multiple wheels slip.

[0026] In some embodiments, the clutch 3 is an electromagnetic clutch.

[0027] The electromagnetic clutch in the present embodiment uses electromagnetic principles to generate engagement force, and its core advantage is extremely fast response speed, with a delay between the on-off electrical control signal and mechanical action usually in the order of milliseconds. Applying this characteristic to the present electrically controlled differential lock, when the vehicle sensors (such as wheel speed sensors) detect wheel slip, the control system can issue an energization instruction to the target electromagnetic clutch within a very short time (e.g., within 10 ms), causing it to quickly lock the corresponding ring gear 5 and achieve instantaneous switching of the power path. This fast response capability is crucial for dynamically changing off-road conditions, minimizing the time window for power loss and promptly delivering torque to the wheels with traction. In addition, the control of the electromagnetic clutch only requires an electrical signal, which has a high degree of integration with the existing vehicle electrical control system (VCU), facilitating complex logic control and cooperation with systems such as ESP and traction control, simplifying the vehicle wiring harness layout and system integration difficulty.

[0028] In some examples, the clutch 3 can also take other forms of controlled engagement and disengagement. For example, an electrically controlled hydraulic multi-plate clutch 3 can be used, which controls the oil pressure by an electric pump to drive the piston to press the friction plate, which has the advantage of being able to transmit greater torque, but the response speed is usually slower than the electromagnetic type, and an additional hydraulic system is required.

[0029] In some embodiments, the clutch 3 is fixedly arranged inside the sealed housing 1, and the rotor end (clutch rotor 4) and the large gear ring 5 are fixedly connected. Specifically, it is fixed by the clutch fixing screw 2.

[0030] In some embodiments, the driving mechanism is a push rod motor 10 or a linear servo motor, and the output end is connected to the rotating shaft of the secondary linkage gear 12 through a connecting rod 11.

[0031] This embodiment defines the specific form of the driving mechanism. The beneficial effect of driving the secondary linkage gear 12 with such a mechanism is that the secondary linkage gear 12 needs to be accurately moved and stopped between two or more preset positions to ensure reliable engagement or disengagement with the primary linkage gear 7. The push rod motor 10 or the linear servo motor has a self-locking feature, which can maintain the position after reaching the target position without the need for continuous energy consumption to maintain the position, which meets the energy saving requirements of vehicles. More importantly, such motors have high control accuracy and good position repeatability, and the end of the stroke can be accurately controlled by the program to ensure that the secondary linkage gear 12 can accurately reach the target positions such as "engagement with the left side only" and "engagement with both sides simultaneously" each time, avoiding gear impact, half-tooth engagement or failure to engage due to position deviation, and greatly improving the working reliability and durability of the system.

[0032] In some examples, the driving mechanism is arranged inside the sealed housing 1.

[0033] In some embodiments, the rotating shaft of the secondary linkage gear 12 is constrained in the guide groove 9 of the sealed housing 1, and the driving mechanism drives the rotating shaft to move along the guide groove 9 to realize the position switching of the secondary linkage gear 12.

[0034] This embodiment constrains the rotating shaft of the secondary linkage gear 12 at both ends or one end in a rigid guide groove 9, so that the movement of the gear is strictly limited to a predetermined track. This ensures the accuracy of the gear movement, and the guide groove 9 is part of the housing, which has a compact structure and high integration, which is beneficial to the miniaturization design of the entire differential lock module. In summary, this embodiment provides key mechanical stability by adding the guide groove 9 structure.

[0035] The guiding function can also be achieved in other ways. For example, a linear bearing can be installed on the shaft of the secondary linkage gear 12, with the outer ring of the bearing mounted on a linear guide rail fixed to the housing. Alternatively, the guide sleeve of the drive mechanism (such as the push rod motor 10) can itself serve as a high-precision guiding mechanism, as long as it can provide sufficient radial support stiffness.

[0036] It should be noted that the shaft of the secondary linkage gear 12 is rotatably inserted into the guide groove 9.

[0037] In some embodiments, the outline of the guide groove 9 is arc-shaped and coaxial with one of the primary linkage gears 7, so that the secondary linkage gear 12 and one of the primary linkage gears 7 are always in meshing.

[0038] This embodiment further optimizes the shape of the guide groove 9, ensuring that the center distance between the secondary linkage gear 12 and the specific primary linkage gear 7 remains constant, equal to the sum of the pitch circle radii of the two gears. This guarantees that they are always in a meshing state, allowing the specific primary linkage gear 7 to provide a guide for the movement of the secondary linkage gear 12, preventing the failure of meshing with the secondary linkage gear 12 due to positional deviation during its movement. This greatly increases the stability of the operation.

[0039] In some embodiments, the electronically controlled differential lock is configured to achieve multiple operating modes by controlling the clutch 3 with the drive mechanism, including: In the all-wheel independent mode, all clutches 3 release all large gear rings 5, and the secondary linkage gear 12 is in the first position; In single-sided synchronous mode, the two clutches 3 on the same side lock the two large gear rings 5 ​​corresponding to them, and the secondary linkage gear 12 is in the first position. In full-wheel synchronization mode, all clutches 3 lock all large gear rings 5, and the secondary linkage gear 12 is in the second position.

[0040] This embodiment clarifies the three basic operating modes of the system and their control logic, thus concretizing the practical value of the invention. The beneficial effects are derived as follows: These three modes precisely cover the needs of all scenarios, from good road surfaces to extreme off-road driving. The "All-Wheel Independent Mode" corresponds to paved roads and normal driving. All clutches 3 are released, each planetary gear set operates freely, and the secondary linkage gear 12 is connected or disengaged only on one side. The four motors are completely independently controlled, fully leveraging the advantages of the fully decoupled system in terms of handling flexibility, steering precision, and energy consumption optimization. The "Single-Side Synchronous Mode" is an optimized solution for common off-road challenges such as cross-axle situations and single-wheel entrapment. When slippage is detected on one side of the vehicle, only the two clutches 3 on that side are locked, forcing the two wheels on that side to rotate synchronously. Power can flow freely between these two wheels and is ultimately transmitted to the single wheel on that side that still has traction, thereby using the combined force of the two motors to achieve single-side entrapment. This mode balances entrapment capability with system complexity. The "All-Wheel Synchronous Mode" is the ultimate means of dealing with the most extreme situations (such as three wheels slipping). Locking all clutches 3 and engaging the secondary linkage gear 12 rigidly connects the outputs of the four motors, forcing all four wheels to rotate at the same speed. At this point, all the power of the vehicle can be transmitted to the only wheel with traction, achieving the maximum possible torque for getting out of trouble. This tiered, intelligently switchable mode strategy gives the vehicle both the agility of daily driving and the strength of off-road extrication.

[0041] In addition to the three basic modes mentioned above, other useful modes can be derived based on the structure of this invention. For example, the "diagonal synchronization mode": by individually controlling the four clutches 3, the large gear rings 5 ​​of the left front and right rear (or right front and left rear) can be locked, and in combination with the appropriate position of the secondary linkage gear 12, diagonal wheels can be coupled to cope with certain special terrains. Or, the "single wheel locking mode": the clutch 3 that locks only one wheel can be used for special power distribution or test scenarios.

[0042] In some embodiments, the protection level of the sealed housing 1 is not lower than IP68.

[0043] This embodiment sets forth specific requirements for the protection level of the housing, which is crucial to ensuring the reliable operation of this invention in harsh environments.

[0044] In some embodiments, the sealing housing 1 is provided with four shaft holes 13, through which the output shaft 8 of the power supply is inserted from the outside of the sealing housing 1 into the sealing housing 1.

[0045] Example 2 The present invention also provides a vehicle including the electronically controlled differential lock of Embodiment 1.

[0046] The vehicle can be any type of wheeled mobile platform, including but not limited to passenger cars (especially SUVs and pickup trucks), commercial vehicles, special-purpose vehicles (firefighting and rescue), military vehicles, unmanned delivery vehicles, AGVs, and construction machinery.

[0047] Example 3 The present invention also provides a method for controlling the above-mentioned electronically controlled differential lock, comprising: Acquire vehicle wheel speed signals and / or wheel slippage signals; Based on the signal, control the target clutch 3 to lock or release the corresponding large gear ring 5; According to the power coupling requirements, the control drive mechanism drives the secondary linkage gear 12 to move to the target position.

[0048] This embodiment protects the control method compatible with the device, achieving hardware and software synergy and transforming the invention from a "static structure" into a "dynamic system." The effect is deduced as follows: A sophisticated mechanical structure requires an intelligent control strategy to maximize its effectiveness. This method, by acquiring signals such as wheel speed in real time, can accurately determine the road surface condition and wheel adhesion of the vehicle (e.g., judging slippage by comparing wheel speed difference with vehicle speed). Based on this judgment, the method can automatically make decisions and execute actions: when a slight slippage on one side is detected, it automatically enters a "single-side synchronous mode"; when the vehicle is severely stuck, it automatically enters a "full-wheel synchronous mode"; and when a good road surface is restored, it automatically reverts to a "full-wheel independent mode." This closed-loop control based on sensor feedback automates and intelligently distributes power, eliminating the need for complex driver operations, significantly lowering the barrier to entry, and ensuring timely and accurate intervention, avoiding human error. Simultaneously, the step of "based on power coupling requirements" in the method also provides an interface for the upper-level control system (such as an autonomous driving decision-making system) to perform forward-looking mode selection, for example, engaging the differential lock in advance before predicting entry into mud to achieve better passability.

[0049] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An electronically controlled differential lock for a fully decoupled four-wheel drive system, characterized in that: include: The four planetary gear sets are divided into two groups arranged symmetrically on the left and right. The sun gears of the two planetary gear sets in each group are coaxially and fixedly connected by a first-stage linkage gear. Each planetary gear set's planet carrier is used to connect to the output shaft of an independent motor; Four clutches, each clutch being disposed at the large gear ring of one of the planetary gear sets, are used to selectively lock or release the corresponding large gear ring; A two-stage linkage gear, activity settings; A drive mechanism is provided for driving the secondary linkage gear to move, giving it at least two working positions: a first position, engaging with at most one of the primary linkage gears; and a second position, engaging with both primary linkage gears simultaneously. A sealed housing is used to enclose all of the aforementioned planetary gear sets, clutches, primary linkage gears, and secondary linkage gears.

2. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 1, characterized in that: The clutch is an electromagnetic clutch.

3. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 1, characterized in that: The drive mechanism is a push rod motor or a linear servo motor, and its output end is connected to the shaft of the secondary linkage gear through a connecting rod.

4. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 3, characterized in that: The shaft of the secondary linkage gear is constrained within the guide groove of the sealed housing, and the drive mechanism drives the shaft to move along the guide groove to achieve position switching of the secondary linkage gear.

5. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 4, characterized in that: The guide groove has an arc-shaped outline and is coaxial with one of the primary linkage gears, so that the secondary linkage gear and one of the primary linkage gears are always in meshing.

6. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 1, characterized in that: The electronically controlled differential lock is configured to achieve multiple operating modes by controlling the clutch and the drive mechanism, including: In the all-wheel independent mode, all the clutches release all the large gear rings, and the secondary linkage gear is in the first position; In the single-sided synchronous mode, the two large gear rings corresponding to the two clutches on the same side are locked, and the secondary linkage gear is in the first position. In the full-wheel synchronization mode, all the clutches are locked, and the secondary linkage gear is in the second position.

7. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 1, characterized in that: The protection level of the sealed housing is not lower than IP68.

8. The electronically controlled differential lock for a fully decoupled four-wheel drive system according to claim 1, characterized in that: The sealing housing is provided with four shaft holes, which allow the output shaft of the motor to be inserted from the outside of the sealing housing into the sealing housing.

9. A vehicle, characterized in that, Includes the electronically controlled differential lock as described in any one of claims 1 to 8.

10. A method for controlling an electronically controlled differential lock as described in any one of claims 1 to 8, characterized in that, include: Acquire vehicle wheel speed signals and / or wheel slippage signals; Based on the signal, control the target clutch to lock or release the corresponding large gear ring; According to the power coupling requirements, the drive mechanism is controlled to drive the secondary linkage gear to move to the target position.

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