Electromagnetic disconnect locking differential and control method

Abstract

The application relates to the field of automobile transmission technology and discloses an electromagnetic disconnection locking type differential and a control method, which comprise a differential transmission module, a power input and support module, an electromagnetic driving module and a power on-off execution and reset retention module, the power input and support module is sleeved outside the differential transmission module, the power input and support module can generate relative circumferential rotation with the differential transmission module, and the power on-off execution and reset retention module is arranged between the power input and support module and the differential transmission module. The application sets a pressure sensing piece at the bottom of the pressure receiving side of a reset wave spring, the pressure sensing piece is used for detecting the axial pressure value corresponding to the compression amount of the reset wave spring in real time, the axial pressure value is used as a feedback parameter to determine the relative meshing state of the combination tooth and the combination tooth ring, the traditional and easily damaged displacement sensor is successfully replaced, and the accuracy of differential power on-off state monitoring is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of automotive transmission technology, specifically to an electromagnetically disconnectable locking differential and its control method. Background Technology

[0002] Electromagnetic disconnect locking differentials are widely used in the transmission systems of four-wheel drive vehicles to control the connection and disconnection of the vehicle's power transmission path. A typical electromagnetic disconnect locking differential mainly consists of a differential transmission module, a power input module, and an electromagnetic actuator module. During vehicle operation, the vehicle controller sends an energizing signal to the electromagnetic coil, generating electromagnetic thrust to drive internal components to engage, completing the power engagement action and realizing the switching of the vehicle's four-wheel drive mode.

[0003] Existing electromagnetic locking differentials lack a mechanical self-locking mechanism when maintaining power engagement. To ensure stable engagement of internal components, the electromagnetic coil must remain continuously energized. Prolonged energization generates heat, causing the coil's operating temperature to rise and leading to thermal degradation of the electromagnetic actuator module. Simultaneously, the continuous energy consumption of the electromagnetic coil increases the vehicle's overall system energy consumption, shortening the driving range of new energy vehicles.

[0004] Conventional electromagnetic locking differentials typically contain a displacement sensor. The vehicle controller relies on this sensor to detect the position and travel of mechanical components, thereby determining the differential's power engagement status. Because the differential is filled with lubricating oil and experiences mechanical vibration, the displacement sensor is susceptible to damage or signal distortion in oily and vibrating environments. When the displacement sensor malfunctions, the vehicle controller cannot obtain accurate feedback data, leading to errors in its determination of the differential's engagement status.

[0005] Existing electromagnetic locking differentials often experience tooth jamming during power engagement, where the internal gear components frequently abut each other. Because traditional control logic lacks a fault-tolerant adjustment procedure to handle this jamming, the vehicle controller maintains a fixed control command even when this occurs. This tooth jamming causes the differential's internal gear components to remain in the jammed position, hindering subsequent engagement and reducing the success rate of power engagement with the electromagnetic locking differential. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an electromagnetic disconnect locking differential and its control method, which solves the problem in existing electromagnetic disconnect locking differentials where the electromagnetic coil is continuously energized while maintaining the power engagement state, causing heat generation and increasing the energy consumption of the entire vehicle system.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The first aspect of the present invention provides an electromagnetic disconnect locking differential, including a differential transmission module, a power input and support module, an electromagnetic drive module, and a power on / off execution and reset holding module;

[0009] The power input and support module is sleeved on the outside of the differential transmission module, and the power input and support module can rotate relative to the differential transmission module in a circumferential direction.

[0010] The power on / off execution and reset holding module is located between the power input and support module and the differential transmission module;

[0011] The electromagnetic drive module is installed on one side of the power input and support module. The power output end of the electromagnetic drive module is connected to the power on / off execution and reset holding module, which is used to provide axial thrust to drive the power on / off execution and reset holding module to switch between the engaged state and the disengaged state, thereby controlling the connection and disconnection of the power transmission route between the power input and support module and the differential transmission module.

[0012] Furthermore, the differential transmission module includes a differential housing, two half-shaft gears, planetary gears, and a slotted shaft. The two half-shaft gears are symmetrically arranged at both ends of the inner cavity of the differential housing. The slotted shaft is fixedly installed on the differential housing. At least two planetary gears are sleeved on the slotted shaft and simultaneously mesh with the two half-shaft gears. A half-shaft gear adjusting shim is provided between each half-shaft gear and the inner wall of the differential housing. A planetary gear shim is provided between each planetary gear and the inner wall of the differential housing. A coiled pin passes through the slotted shaft and the differential housing, thereby achieving a circumferential fixed connection between the slotted shaft and the differential housing.

[0013] Furthermore, the power input and support module includes an integrated main reduction gear and a coupling gear ring. The coupling gear ring is fixedly connected to the outer circumferential surface of the differential housing. The right end journal of the differential housing passes through the internal mounting hole of the integrated main reduction gear. There is a radial clearance between the outer circumferential surface of the coupling gear ring and the inner wall of the integrated main reduction gear, allowing for relative circumferential rotation. An annular flange structure is provided on the outer circumferential surface of the differential housing. A first bearing is provided between the annular flange structure and the integrated main reduction gear. A second bearing is installed at the journal of the differential housing on one side of the integrated main reduction gear for dual positioning.

[0014] Furthermore, the electromagnetic drive module includes an electromagnetic coil, a push ring, a push plate, and a reset spring. The electromagnetic coil is fixedly installed on the outside of the left end journal of the integrated main reduction gear. The push ring is sleeved on the left end journal of the integrated main reduction gear and located to the right of the electromagnetic coil, and can move axially to the left by the electromagnetic force of the electromagnetic coil. The reset spring is sleeved on the right end journal of the integrated main reduction gear and abuts against the right end face of the push ring. The push plate is disposed inside the integrated main reduction gear. Push teeth are distributed circumferentially on one end face of the push plate. A support column is provided at the other end of the push plate. An annular groove is opened on the outer circumferential surface of the support column. The support column passes through the integrated main reduction gear and is fixedly connected to the push ring. A claw that engages in the annular groove is provided on the inner circumferential surface of the push ring.

[0015] Furthermore, the power on / off execution and reset holding module includes a coupling sleeve, a coupling tooth, and a retaining ring. The coupling sleeve is circumferentially fixedly connected to the integrated main reduction gear and axially limited via an external spline. An annular retaining ring groove is formed on the inner wall of the integrated main reduction gear, and the retaining ring is installed in the annular retaining ring groove to axially limit the coupling sleeve. A stepped groove structure is provided on the inner circumferential surface of the coupling sleeve. The coupling tooth is an annular structure and is coaxially and movably arranged on the inner side of the coupling sleeve. A bottom tooth is provided on the outer circumferential surface of the coupling tooth to slide with the stepped groove structure. A top tooth is provided on the left end face of the coupling tooth, and the top tooth is used to mesh with the coupling tooth ring. The left end face of the pusher plate selectively abuts against the bottom tooth of the coupling tooth.

[0016] Furthermore, the stepped groove structure includes a low groove, a first high groove, and a second high groove that are alternately distributed circumferentially. The bottom depth of the low groove is greater than the bottom depth of the first and second high grooves. The low groove and the high groove are smoothly transitioned by an inclined surface. The bottom tooth of the connecting tooth can slide relative to the low groove and the first and second high grooves along the inclined surface.

[0017] Furthermore, the power on / off execution and reset holding module also includes a sliding sleeve and a disc spring. The sliding sleeve is coaxially sleeved on the outside of the right end journal of the differential housing. The sliding sleeve is clearance-fitted with the differential housing and is axially limited. The disc spring is coaxially sleeved on the outside of the sliding sleeve. The right end of the disc spring abuts against the left end face of the sliding sleeve. The left end of the disc spring is engaged in the annular fixing groove opened on the right end face of the engagement tooth to provide a continuous axial preload to the engagement tooth.

[0018] Furthermore, the electromagnetic drive module also includes a pressure-sensitive plate, which is disposed on the bottom pressure side of the reset spring and is used to detect the axial pressure corresponding to the compression amount of the reset spring.

[0019] The second aspect of the present invention provides a control method for an electromagnetically disconnected locking differential, including a power engagement process and a power disconnect process;

[0020] The power combination process specifically includes the following steps:

[0021] The vehicle controller collects vehicle operating parameters. When it determines that the real-time operating parameters meet the preset four-wheel drive triggering conditions, it enters the power engagement control program and generates a speed synchronization command.

[0022] Based on the speed synchronization command, the vehicle controller sends a speed synchronization signal to the motor controller, and the motor controller adjusts the speed of the auxiliary drive motor to control the relative speed difference between the integrated main reduction gear and the differential housing within ±5 rpm.

[0023] The relative speed difference is continuously monitored. When it is determined that the relative speed difference is stable within ±5 rpm and reaches the set stabilization time, the vehicle controller outputs an energizing pulse signal to the electromagnetic coil to trigger the electromagnetic coil to generate electromagnetic thrust.

[0024] During the axial movement of the push plate driven by the electromagnetic thrust, the axial pressure value corresponding to the compression of the reset spring is detected in real time by the pressure-sensitive plate set at the bottom of the reset spring, and the axial pressure value is used as a feedback parameter to determine the meshing state of the engagement teeth and the engagement ring.

[0025] Based on the feedback parameters, when the axial pressure value detected by the pressure sensor stabilizes within the preset engagement pressure threshold range, it is determined that the power transmission route is successfully engaged. Subsequently, the vehicle controller stops outputting energizing pulse signals to the electromagnetic coil, and the system enters a zero-power mechanical self-locking state.

[0026] Wherein, the reference axial pressure borne by the reset spring when the engagement tooth is completely in the first high position groove under the calibration state is defined as the calibration value P1, and the pressure threshold range of the engagement state is set to be within 5% of the calibration value P1.

[0027] The power disconnection process specifically includes the following steps:

[0028] When the vehicle operating parameters are determined to meet the preset power disconnection conditions, the vehicle controller sends a signal to the motor controller, which then controls the auxiliary drive motor to perform a torque reduction operation until the output torque drops to 0 Nm.

[0029] After confirming that the output torque of the auxiliary drive motor is zero, the vehicle controller outputs an energizing pulse signal to the electromagnetic coil to generate an electromagnetic thrust that pushes the push plate to the left to release the mechanical self-locking.

[0030] During the mechanical self-locking release process, the axial pressure value corresponding to the compression of the reset spring is detected in real time by the pressure sensing plate. When the axial pressure value reaches the pressure threshold range of the engagement state, it is determined that the power transmission route has been cut off. Then the vehicle controller stops outputting energizing pulse signals to the electromagnetic coil, and the differential returns to the disconnected mode.

[0031] Furthermore, the power engagement process also includes a fault-tolerant control program for engagement failures, specifically comprising the following steps:

[0032] If the continuous energization time of the electromagnetic coil exceeds 120ms and the feedback parameter still does not reach the pressure threshold range of the engagement state, the current engagement action is determined to have failed and the vehicle controller stops outputting the energizing pulse signal.

[0033] In the event of a failed engagement, the relative phase between the integrated main reduction gear and the differential housing is adjusted by ±3°, and the adjusted state is used as a new initial condition to re-execute the power engagement control program.

[0034] The above solution achieves the following beneficial technical effects:

[0035] This invention provides a stepped groove structure with a low groove and a high groove on the inner circumferential surface of the coupling sleeve. In conjunction with the bottom teeth on the outer circumferential surface of the coupling teeth, when the pusher pushes the coupling teeth into the first high groove and completes the connection of the power transmission route, the electromagnetic coil can be de-energized to maintain a complete mechanical self-locking state. This avoids the heat generation problem caused by the continuous energization of the electromagnetic coil and reduces the system energy consumption of the entire vehicle.

[0036] This invention replaces the traditional and easily damaged displacement sensor by setting a pressure-sensing plate at the bottom of the compression side of the reset spring. The pressure-sensing plate detects the axial pressure value corresponding to the compression of the reset spring in real time, and uses the axial pressure value as a feedback parameter to determine the relative meshing state of the engagement teeth and engagement ring. This effectively improves the accuracy of differential power on / off status monitoring.

[0037] This invention adds a fault-tolerant control program to the control process to address the failure of the engagement action. When the continuous energization time of the electromagnetic coil exceeds the limit and the feedback parameters do not reach the engagement state pressure threshold range, the vehicle controller actively controls the integrated main reduction gear and the differential housing to complete the relative phase adjustment of positive and negative three degrees and restart the power engagement process. This solves the problem of gear tooth jamming and improves the success rate of differential power engagement. Attached Figure Description

[0038] Figure 1 This is a perspective view of the present invention;

[0039] Figure 2a This is a schematic cross-sectional view of the differential housing of the present invention;

[0040] Figure 2b for Figure 2a A magnified view of the local structure;

[0041] Figure 3 This is a schematic diagram of the pusher structure of the present invention;

[0042] Figure 4 This is a schematic diagram of the connecting sleeve structure of the present invention;

[0043] Figure 5 This is a schematic diagram of the connecting tooth structure of the present invention;

[0044] Figure 6 This is a schematic diagram of the control method of the present invention.

[0045] The components include: 1. Integrated main reduction gear; 2. First bearing; 3. Differential housing; 301. Engaging gear ring; 4. Slotted shaft; 5. Coiled pin; 6. Planetary gear shim; 7. Planetary gear; 8. Half-shaft gear; 9. Half-shaft gear adjusting shim; 10. Electromagnetic coil; 11. Pressure sensing plate; 12. Second bearing; 13. Push plate; 1301. Push tooth; 1302. Annular groove; 1303. Support column; 14. Engaging sleeve; 1401. Low position groove; 1402. First high position groove; 1403. Second high position groove; 1404. Inclined surface; 15. Snap ring; 16. Disc spring; 17. Engaging tooth; 1701. Annular fixing groove; 1702. Bottom tooth; 1703. Top tooth; 18. Sliding sleeve; 19. Push ring; 20. Return spring. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Please see the appendix Figure 1 In addition to 2, the present invention provides an electromagnetic disconnect locking differential, including a differential transmission module, a power input and support module, an electromagnetic drive module, and a power on / off execution and reset holding module;

[0048] The power input and support module is sleeved on the outside of the differential transmission module, and the power input and support module can rotate relative to the differential transmission module in a circumferential direction.

[0049] The power on / off execution and reset holding module is located between the power input and support module and the differential transmission module;

[0050] The electromagnetic drive module is installed on one side of the power input and support module. The power output end of the electromagnetic drive module is connected to the power on / off execution and reset holding module, which is used to provide axial thrust to drive the power on / off execution and reset holding module to switch between the engaged and disengaged states, thereby controlling the connection and disconnection of the power transmission route between the power input and support module and the differential transmission module.

[0051] In one specific embodiment, the electromagnetic disconnect locking differential of the present invention is assembled sequentially from the inside out and from right to left to form a complete transmission and control assembly. The power input and support module is externally mounted as the power input source, while the differential transmission module is located internally and responsible for differential output to the left and right half-shafts. The power on / off execution and reset holding module is cleverly arranged between the two, acting as a clutch mechanism. The electromagnetic drive module is installed on one side of the power input and support module, generating instantaneous axial thrust to drive the stepped grooves of the internal mechanical structure for state switching.

[0052] To address the technical problem of energy loss (specifically including motor iron and copper losses, gear churning losses, and bearing friction losses) in four-wheel drive systems under light load conditions (such as two-wheel drive cruise and coasting) due to the high-speed rotation of the non-drive-end motor, reducer, and differential caused by the wheels dragging them, and the resulting safety hazards such as gear squealing and motor back EMF, this invention is initially set to a disconnected mode. When the electromagnetic drive module is not powered, the power transmission path between the power input and support module and the differential transmission module is disconnected. The dragging torque generated by the rotation of the non-drive-end wheels only drives the differential transmission module to idle, without driving the power input and support module or the external motor, thereby eliminating the dragging loss of the non-drive-end powertrain.

[0053] To address the technical problems of existing electromagnetic disconnect differentials that rely entirely on continuous power supply to generate electromagnetic force to maintain their state, resulting in increased energy consumption and easy coil overheating and aging, thus reducing the service life of the entire vehicle, this invention provides instantaneous axial thrust through an electromagnetic drive module. Combined with the limiting function of the internal mechanical structure of the power on / off execution and reset holding module, the power supply to the electromagnetic drive module is cut off in the engaged state, and the power transmission path is maintained by the mechanical limiting structure, thereby reducing the power consumption required to maintain the state.

[0054] See appendix Figures 2a-2bThe differential transmission module includes a differential housing 3, two half-shaft gears 8, planetary gears 7, and a slotted shaft 4. The two half-shaft gears 8 are symmetrically arranged at both ends of the inner cavity of the differential housing 3. The slotted shaft 4 is fixedly installed on the differential housing 3. At least two planetary gears 7 are sleeved on the slotted shaft 4 and mesh with the two half-shaft gears 8 simultaneously. A half-shaft gear adjusting shim 9 is provided between each half-shaft gear 8 and the inner wall of the differential housing 3. A planetary gear shim 6 is provided between each planetary gear 7 and the inner wall of the differential housing 3. A coiled pin 5 passes through the slotted shaft 4 and the differential housing 3, and the circumferential fixed connection between the slotted shaft 4 and the differential housing 3 is achieved by the coiled pin 5.

[0055] In one specific embodiment, a closed transmission cavity is formed inside the differential housing 3. The external splines of the two half-shaft gears 8 are respectively used to mesh with the internal splines of the left and right half-shafts to output power. At least two planetary gears 7 are distributed circumferentially along the differential housing 3 and simultaneously mesh with the bevel tooth surfaces of the two half-shaft gears 8. A half-shaft gear adjusting shim 9 is provided between each half-shaft gear 8 and the inner wall of the differential housing 3, and a planetary gear shim 6 is provided between each planetary gear 7 and the inner wall of the differential housing 3. The half-shaft gear adjusting shims 9 and planetary gear shims 6 are used to reduce transmission friction and adjust gear meshing clearance.

[0056] Planetary gear 7 and planetary gear washer 6 are coaxially sleeved on the slotted shaft 4. The two ends of the slotted shaft 4 are respectively inserted into the shaft holes opened at the corresponding positions of the differential housing 3. A coiled pin 5 is provided between the slotted shaft 4 and the differential housing 3. The circumferential fixed connection is achieved through the coiled pin 5, so that the planetary gear 7 can rotate around the slotted shaft 4 and revolve synchronously with the differential housing 3.

[0057] Please see the appendix Figure 1 2. The power input and support module includes an integrated main reduction gear 1 and a connecting gear ring 301. The connecting gear ring 301 is fixedly connected to the outer circumferential surface of the differential housing 3. The right end journal of the differential housing 3 passes through the internal mounting hole of the integrated main reduction gear 1. There is a radial clearance between the outer circumferential surface of the connecting gear ring 301 and the inner wall of the integrated main reduction gear 1, which allows for relative circumferential rotation. An annular flange structure is provided on the outer circumferential surface of the differential housing 3. A first bearing 2 is provided between the annular flange structure and the integrated main reduction gear 1. A second bearing 12 is installed at the journal of the differential housing 3 passing through one side of the integrated main reduction gear 1 to achieve dual positioning.

[0058] In one specific embodiment, the outer gear teeth of the integrated main reduction gear 1 mesh with an external reducer gear to receive power. The gear ring 301 is fixedly connected to the outer circumferential surface of the right end of the differential housing 3 by welding and rotates synchronously with the differential housing 3. An annular flange structure is provided on the outer circumferential surface of the differential housing 3, and a first bearing 2 is provided between the annular flange structure and the integrated main reduction gear 1. Specifically, a thrust bearing, as part of the first bearing 2, is installed between the right end face of the annular flange structure and the left end face of the integrated main reduction gear 1 to withstand the axial load generated during operation.

[0059] A needle roller bearing, which is another part of the first bearing 2, is installed between the outer circumferential surface below the annular flange structure and the inner wall of the integrated main reduction gear 1. An annular retaining ring groove is provided on the inner wall of the integrated main reduction gear 1 at the position corresponding to the right end of the needle roller bearing. A hole elastic retaining ring is installed in the annular retaining ring groove to limit the axial displacement of the needle roller bearing.

[0060] A second bearing 12 is installed at the right end journal of the differential housing 3. The second bearing 12 is a deep groove ball bearing. The inner ring of the deep groove ball bearing is interference-fitted with the journal of the differential housing 3, and the outer ring is interference-fitted with the bearing seat of the external reducer housing. This is used to achieve dual axial and radial positioning of the entire differential assembly and to maintain the free circumferential relative rotation capability of the differential housing 3 and the engagement gear ring 301 relative to the integrated main reduction gear 1.

[0061] Please see the appendix Figure 2a , 2b 3. The electromagnetic drive module includes an electromagnetic coil 10, a push ring 19, a push plate 13, and a reset spring 20. The electromagnetic coil 10 is fixedly installed on the outside of the left end journal of the integrated main reduction gear 1. The push ring 19 is sleeved on the left end journal of the integrated main reduction gear 1 and located on the right side of the electromagnetic coil 10. It can move axially to the left by the electromagnetic force of the electromagnetic coil 10. The reset spring 20 is sleeved on the right end journal of the integrated main reduction gear 1 and abuts against the right end face of the push ring 19. The push plate 13 is set inside the integrated main reduction gear 1. Push teeth 1301 are distributed circumferentially on one end face of the push plate 13. A support column 1303 is provided at the other end of the push plate 13. An annular groove 1302 is opened on the outer circumferential surface of the support column 1303. The support column 1303 passes through the integrated main reduction gear 1 and is fixedly connected to the push ring 19. A claw that engages in the annular groove 1302 is provided on the inner circumferential surface of the push ring 19.

[0062] In one specific embodiment, the electromagnetic coil 10 is wound on a coil frame and fixedly installed in the mounting groove on the outer side of the journal at the left end of the integrated main reduction gear 1. The push ring 19 is made of a high-permeability magnetic material. The right end of the reset spring 20 abuts against the right end face of the push ring 19, and the left end abuts against the right end face of the integrated main reduction gear 1, which is used to provide the axial elastic force required for the push ring 19 to reset to the right after the electromagnetic coil 10 is de-energized. Four axially extending support columns 1303 are evenly distributed circumferentially at the root of the push plate 13. Each support column 1303 has an annular groove 1302 on its outer circumferential surface, and a ring of push teeth 1301 is distributed on the end face of the push plate 13. Four inwardly protruding claws are provided on the inner circumferential surface of the push ring 19 corresponding to the positions of the four support columns 1303. Four through holes are provided on the right end face of the integrated main reduction gear 1, corresponding to the positions of the four support columns 1303. The support columns 1303 pass through the through holes from left to right, and the claws of the push ring 19 are precisely engaged in the annular grooves 1302 of the support columns 1303 to form a rigid fixed connection, so that the push ring 19 and the push plate 13 move synchronously axially.

[0063] Please see the appendix Figure 2a , 2b The power on / off execution and reset holding module includes a coupling sleeve 14, a coupling tooth 17, and a retaining ring 15. The coupling sleeve 14 is circumferentially fixed and axially limited by an external spline to the integrated main reduction gear 1. An annular retaining ring groove is provided on the inner wall of the integrated main reduction gear 1. The retaining ring 15 is installed in the annular retaining ring groove to axially limit the coupling sleeve 14. A stepped groove structure is provided on the inner circumferential surface of the coupling sleeve 14. The coupling tooth 17 is an annular structure and is coaxially and movably arranged on the inner side of the coupling sleeve 14. A bottom tooth 1702 is provided on the outer circumferential surface of the coupling tooth 17 to slide with the stepped groove structure. A top tooth 1703 is provided on the left end face of the coupling tooth 17. The top tooth 1703 is used to mesh with the coupling tooth ring 301. The left end face of the push plate 13 selectively abuts against the bottom tooth 1702 of the coupling tooth 17.

[0064] In one specific embodiment, an internal spline groove is machined on the inner disc of the integrated main reduction gear 1. The engaging sleeve 14 meshes with the internal spline groove of the integrated main reduction gear 1 through an external spline, maintaining the synchronous rotation of the engaging sleeve 14 and the integrated main reduction gear 1. An annular retaining ring groove is formed on the inner wall of the integrated main reduction gear 1 at the left end position of the engaging sleeve 14. A retaining ring 15 is installed in the annular retaining ring groove. The retaining ring 15 acts as an elastic retaining ring for the hole to limit the axial displacement of the engaging sleeve 14 and prevent it from moving during operation. Multiple bottom teeth 1702 are evenly distributed circumferentially on the outer circumferential surface of the engaging tooth 17.

[0065] When the power is disconnected, the electromagnetic coil 10 is not energized. The push ring 19 is located at the rightmost position in the axial direction under the elastic force of the reset spring 20, and synchronously drives the push plate 13 to move. The left end face of the push plate 13 is flush with the right end face of the coupling sleeve 14. The bottom tooth 1702 of the coupling tooth 17 is located in the low groove of the stepped groove structure and is in contact with the left end face of the push plate 13. The top tooth 1703 is completely separated from the coupling tooth ring 301. At this time, the power transmission path is disconnected.

[0066] Please see the appendix Figure 2a , 2b 4. The stepped groove structure includes a low groove 1401, a first high groove 1402 and a second high groove 1403 that are alternately distributed along the circumference. The bottom depth of the low groove 1401 is greater than the bottom depth of the first high groove 1402 and the second high groove 1403. The low groove 1401 and the high groove are smoothly transitioned by an inclined surface 1404. The bottom tooth 1702 of the connecting tooth 17 can slide relative to the low groove 1401 and the first high groove 1402 and the second high groove 1403 along the inclined surface 1404.

[0067] In one specific embodiment, during the power connection process, the electromagnetic coil 10 is energized to generate electromagnetic attraction, which overcomes the elastic force of the reset spring 20 and pushes the push plate 13 to move axially to the left. The arc surface of the end face of the push plate 13 first contacts the inclined surface of the bottom tooth 1702 of the engagement tooth 17, decomposing the generated axial thrust into axial and circumferential components. When the bottom tooth 1702 of the engagement tooth 17 is pushed out of the low slot 1401, the engagement tooth 17 is driven to rotate by the circumferential component, causing the bottom tooth 1702 to rotate into the high slot area. Then, the electromagnetic coil 10 is de-energized, and the push ring 19 resets to the right under the elastic force of the reset spring 20, simultaneously driving the push plate 13 to reset to the right.

[0068] Under the combined action of the reverse elastic force of the disc spring 16 and the axial thrust of the push plate 13, the bottom tooth 1702 of the engaging tooth 17 slides smoothly down the inclined or sloping surface at the entrance of the second high-position groove 1403 and finally falls into the bottom of the first high-position groove 1402 and is axially limited. At this time, the top tooth 1703 of the engaging tooth 17 meshes with the engaging tooth ring 301, realizing the connection of the power transmission route.

[0069] At this time, the engaging tooth 17 is maintained in the engaging state by the mechanical limit of the bottom tooth 1702 located in the first high position groove 1402. During the power disconnection process, the electromagnetic coil 10 is energized again, pushing the push plate 13 to move to the left and pushing the bottom tooth 1702 out of the first high position groove 1402. Then the electromagnetic coil 10 is de-energized, and the bottom tooth 1702 slides along the inclined surface of the second high position groove 1403 into the bottom of the low position groove 1401, completing the disconnection of the engaging tooth 17 and the engaging tooth ring 301, and returning to the power disconnection state.

[0070] Please see the appendix Figure 2a , 2b The power on / off execution and reset holding module also includes a sliding sleeve 18 and a disc spring 16. The sliding sleeve 18 is coaxially sleeved on the outside of the right end journal of the differential housing 3. The sliding sleeve 18 is clearance-fitted with the differential housing 3 and is axially limited. The disc spring 16 is coaxially sleeved on the outside of the sliding sleeve 18. The right end of the disc spring 16 abuts against the left end face of the sliding sleeve 18. The left end of the disc spring 16 is engaged in the annular fixing groove 1701 opened on the right end face of the engagement tooth 17 to provide a continuous axial preload to the engagement tooth 17.

[0071] In one specific embodiment, an annular retaining ring groove is provided on the journal of the differential housing 3 corresponding to the right end of the sliding sleeve 18. A shaft elastic retaining ring is installed in the annular retaining ring groove to limit the axial displacement of the sliding sleeve 18. The sliding sleeve 18 and the differential housing 3 are configured with a clearance fit, allowing the sliding sleeve 18 to rotate freely circumferentially relative to the differential housing 3. The disc spring 16 is in a pre-compressed state, with its left end engaged in the annular fixing groove 1701 of the engaging tooth 17, maintaining the synchronous rotation of the disc spring 16 and the engaging tooth 17. The axial elastic force provided by the disc spring 16, pointing to the right end, keeps the bottom tooth 1702 of the engaging tooth 17 in contact with the bottom surface of the stepped groove of the engaging sleeve 14, limiting the radial displacement of the engaging tooth 17 during rotation to prevent it from shifting; and when the push plate 13 moves to the left, it pushes the bottom tooth 1702 of the engaging tooth 17 to slide along the inclined surface 1404 from the first high groove 1402 to the low groove 1401 to complete the disconnection and reset.

[0072] Please see the appendix Figure 2a , 2b The electromagnetic drive module also includes a pressure sensing plate 11, which is located on the bottom pressure side of the reset spring 20 and is used to detect the axial pressure corresponding to the compression amount of the reset spring 20.

[0073] In one specific embodiment, the pressure sensor 11 is used to acquire the detection pressure parameter, and the vehicle controller determines the engagement state based on the detection pressure parameter.

[0074] See appendix Figure 6 This embodiment also provides a control method for an electromagnetically disconnectable locking differential, specifically including two processes: power engagement and power disconnection.

[0075] The power combination process specifically includes the following steps:

[0076] After the system completes the power-on initialization, the vehicle controller executes the system self-test program and the sensor self-calibration program. The sensor self-calibration program is as follows: the vehicle controller reads the reference pressure value of the pressure sensor 11 in the initial disconnected state and performs zero-point correction to eliminate the zero-point drift error of the pressure sensor 11. Then the vehicle controller determines whether the system self-test program has passed. If the system self-test program fails, the vehicle controller sends a signal to display the fault light. If the system self-test program passes, the following steps are performed.

[0077] The vehicle control unit (VCU) collects vehicle operating parameters. When it determines that the real-time operating parameters meet the preset four-wheel drive triggering conditions (specifically, the vehicle exits two-wheel drive cruise or coasting mode, and the throttle pedal opening or the front and rear wheel speed difference reaches the preset threshold for enhanced traction), it enters the power engagement control program and generates a speed synchronization command. If it determines that the real-time operating parameters do not meet the preset four-wheel drive triggering conditions, the vehicle control unit maintains the current vehicle operating mode and continues to collect vehicle operating parameters.

[0078] Based on the speed synchronization command, the vehicle controller sends a speed synchronization signal to the motor controller (MCU). The motor controller adjusts the speed of the auxiliary drive motor to control the relative speed difference between the integrated main reduction gear (1) and the differential housing (3) within ±5 rpm.

[0079] The relative speed difference is continuously monitored. When it is determined that the relative speed difference is stable within ±5 rpm and reaches the set stabilization time (the stabilization time is set to a value between 20 ms and 50 ms to ensure that the speed is completely synchronized rather than transiently fluctuating), the vehicle controller outputs an energizing pulse signal to the solenoid coil 10 to trigger the solenoid coil 10 to generate electromagnetic thrust. If it is determined that the relative speed difference is not stable within ±5 rpm or has not reached the set stabilization time, the motor controller continuously adjusts the speed of the auxiliary drive motor.

[0080] During the axial movement of the push plate 13 driven by electromagnetic thrust, the pressure plate 11 set at the bottom of the reset spring 20 detects the axial pressure value corresponding to the compression of the reset spring 20 in real time, and uses the axial pressure value as a feedback parameter to determine the meshing state of the engagement tooth 17 and the engagement tooth ring 301.

[0081] Based on the feedback parameters, when the axial pressure value detected by the pressure sensor 11 stabilizes within the preset engagement state pressure threshold range, it is determined that the power transmission route is successfully engaged. Subsequently, the vehicle controller stops outputting energizing pulse signals to the electromagnetic coil 10, and the system enters a zero-power mechanical self-locking state. Among them, the reference axial pressure borne by the reset spring 20 when the engagement tooth 17 is fully inserted into the first high-position groove 1402 in the calibration state is defined as the calibration value P1, and the engagement state pressure threshold range is set to be within 5% of the calibration value P1.

[0082] Conversely, if the continuous energization time of the electromagnetic coil 10 exceeds 120ms and the feedback parameter (i.e., the axial pressure value detected by the pressure sensor 11) still does not reach the pressure threshold range of the engagement state, the current engagement action is determined to be a failure, and the vehicle controller stops outputting the energizing pulse signal.

[0083] In response to the failure of the above-mentioned engagement action, after adjusting the relative phase of the integrated main reduction gear 1 and the differential housing (3) by ±3°, the adjusted state is used as the new initial condition. After adjustment, the aforementioned steps are executed again to re-monitor the relative speed difference and re-engage the action.

[0084] The power disconnection process specifically includes the following steps:

[0085] When the vehicle operating parameters are determined to meet the preset power disconnection conditions (specifically, when the vehicle enters light load operating conditions such as two-wheel drive cruise or coasting), the vehicle controller sends a signal to the motor controller. The motor controller controls the output torque of the auxiliary drive motor to perform a torque reduction operation until it drops to 0 Nm. If the vehicle operating parameters are determined not to meet the preset power disconnection conditions, the vehicle controller maintains the four-wheel drive mode and continuously monitors the vehicle operating parameters.

[0086] After confirming that the output torque of the auxiliary drive motor is zero, the vehicle controller outputs an energizing pulse signal to the electromagnetic coil 10 to generate an electromagnetic thrust that pushes the push plate 13 to the left to release the mechanical self-locking.

[0087] During the release of the mechanical self-locking mechanism, the axial pressure value corresponding to the compression of the reset spring 20 is detected in real time by the pressure sensing plate 11. When it is determined that the real-time monitored axial pressure value reaches the pressure threshold range of the engagement state, it is determined that the power transmission route has been cut off. Then, the vehicle controller stops outputting energizing pulse signals to the solenoid coil 10, and the differential returns to the disengaged mode. If it is determined that the real-time monitored axial pressure value has not reached the pressure threshold range of the engagement state, the vehicle controller maintains the solenoid coil 10 energized and continues to detect the axial pressure value.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electromagnetically disconnectable locking differential, characterized in that, It includes a differential transmission module, a power input and support module, an electromagnetic drive module, and a power on / off execution and reset holding module; The power input and support module is sleeved on the outside of the differential transmission module, and the power input and support module can rotate relative to the differential transmission module in a circumferential direction. The power on / off execution and reset holding module is located between the power input and support module and the differential transmission module; The electromagnetic drive module is installed on one side of the power input and support module. The power output end of the electromagnetic drive module is connected to the power on / off execution and reset holding module, which is used to provide axial thrust to drive the power on / off execution and reset holding module to switch between the engaged state and the disengaged state, thereby controlling the connection and disconnection of the power transmission route between the power input and support module and the differential transmission module.

2. The electromagnetic disconnect locking differential according to claim 1, characterized in that, The differential transmission module includes a differential housing (3), two half-shaft gears (8), planetary gears (7), and a slotted shaft (4). The two half-shaft gears (8) are symmetrically arranged at both ends of the inner cavity of the differential housing (3). The slotted shaft (4) is fixedly installed on the differential housing (3). At least two planetary gears (7) are sleeved on the slotted shaft (4) and mesh with the two half-shaft gears (8) at the same time. A half-shaft gear adjusting shim (9) is provided between each half-shaft gear (8) and the inner wall of the differential housing (3). A planetary gear shim (6) is provided between each planetary gear (7) and the inner wall of the differential housing (3). A coiled pin (5) passes through the slotted shaft (4) and the differential housing (3). The circumferential fixed connection between the slotted shaft (4) and the differential housing (3) is achieved by the coiled pin (5).

3. The electromagnetic disconnect locking differential according to claim 2, characterized in that, The power input and support module includes an integrated main reduction gear (1) and a connecting gear ring (301). The connecting gear ring (301) is fixedly connected to the outer circumferential surface of the differential housing (3). The right end journal of the differential housing (3) passes through the internal mounting hole of the integrated main reduction gear (1). There is a radial clearance between the outer circumferential surface of the connecting gear ring (301) and the inner wall of the integrated main reduction gear (1) that allows for relative circumferential rotation. An annular flange structure is provided on the outer circumferential surface of the differential housing (3). A first bearing (2) is provided between the annular flange structure and the integrated main reduction gear (1). A second bearing (12) is installed at the journal of the differential housing (3) on one side of the integrated main reduction gear (1) to achieve dual positioning.

4. The electromagnetic disconnect locking differential according to claim 3, characterized in that, The electromagnetic drive module includes an electromagnetic coil (10), a push ring (19), a push plate (13), and a reset spring (20). The electromagnetic coil (10) is fixedly installed on the outside of the left end journal of the integrated main reduction gear (1). The push ring (19) is sleeved on the left end journal of the integrated main reduction gear (1) and located to the right of the electromagnetic coil (10). It can be axially moved to the left by the electromagnetic force of the electromagnetic coil (10). The reset spring (20) is sleeved on the right end journal of the integrated main reduction gear (1) and is located to the right of the push ring (19). The right end face of the pusher (13) is abutted, and the pusher (13) is set inside the integrated main reduction gear (1). One end face of the pusher (13) is provided with pusher teeth (1301) distributed in the circumferential direction. The other end of the pusher (13) is provided with a support column (1303). The outer circumferential surface of the support column (1303) is provided with an annular groove (1302). The support column (1303) passes through the integrated main reduction gear (1) and is fixedly connected to the pusher ring (19). The inner circumferential surface of the pusher ring (19) is provided with a claw that can be inserted into the annular groove (1302).

5. The electromagnetic disconnect locking differential according to claim 4, characterized in that, The power on / off execution and reset holding module includes a coupling sleeve (14), a coupling gear (17), and a retaining ring (15). The coupling sleeve (14) is circumferentially fixedly connected to the integrated main reduction gear (1) and axially limited by an external spline. An annular retaining ring groove is provided on the inner wall of the integrated main reduction gear (1). The retaining ring (15) is installed in the annular retaining ring groove to axially limit the coupling sleeve (14). A stepped groove structure is provided on the inner circumferential surface of the coupling sleeve (14). The connecting tooth (17) is a ring structure and is coaxially and movably disposed on the inner side of the connecting sleeve (14). The outer circumferential surface of the connecting tooth (17) is provided with a bottom tooth (1702) that slides with the stepped groove structure. The left end face of the connecting tooth (17) is provided with a top tooth (1703). The top tooth (1703) is used to mesh with the connecting tooth ring (301). The left end face of the push plate (13) selectively abuts against the bottom tooth (1702) of the connecting tooth (17).

6. The electromagnetic disconnect locking differential according to claim 5, characterized in that, The stepped groove structure includes a low groove (1401), a first high groove (1402), and a second high groove (1403) that are alternately distributed along the circumference. The bottom depth of the low groove (1401) is greater than the bottom depth of the first high groove (1402) and the second high groove (1403). The low groove (1401) and the high groove are smoothly transitioned by an inclined surface (1404). The bottom tooth (1702) of the connecting tooth (17) can slide relative to the low groove (1401) and the first high groove (1402) and the second high groove (1403) along the inclined surface (1404).

7. The electromagnetic disconnect locking differential according to claim 5, characterized in that, The power on / off execution and reset holding module also includes a sliding sleeve (18) and a disc spring (16). The sliding sleeve (18) is coaxially sleeved on the outside of the right end journal of the differential housing (3). The sliding sleeve (18) is clearance-fitted with the differential housing (3) and is axially limited. The disc spring (16) is coaxially sleeved on the outside of the sliding sleeve (18). The right end of the disc spring (16) abuts against the left end face of the sliding sleeve (18). The left end of the disc spring (16) is inserted into the annular fixing groove (1701) opened on the right end face of the engagement tooth (17) to provide a continuous axial preload to the engagement tooth (17).

8. The electromagnetic disconnect locking differential according to claim 4, characterized in that, The electromagnetic drive module also includes a pressure-sensitive plate (11), which is disposed on the bottom pressure side of the reset spring (20) and is used to detect the axial pressure corresponding to the compression amount of the reset spring (20).

9. A control method for an electromagnetically disconnected locking differential, characterized in that, The electromagnetic disconnect locking differential as described in any one of claims 1-8 includes a power engagement process and a power disconnect process. The power combination process specifically includes the following steps: After completing the power-on initialization, the vehicle controller executes the system self-test program and sensor self-calibration program, and determines whether the system self-test program passes. If the system self-test program fails, the vehicle controller sends a signal to display the fault light; if the system self-test program passes, the controller sends a signal to display the fault light. After completing the power-on initialization, the vehicle controller executes the system self-test program and the sensor self-calibration program. The sensor self-calibration procedure is as follows: the vehicle controller reads the reference pressure value of the pressure sensor (11) in the initial disconnected state and performs zero-point correction to eliminate the zero-point drift error of the pressure sensor (11); The vehicle controller then determines whether the system self-test program has passed. If the system self-test program has failed, the vehicle controller sends a signal to display a fault light. If the system self-test program is deemed to pass, the vehicle controller collects vehicle operating parameters. When the vehicle operating parameters are determined to meet the preset four-wheel drive triggering conditions, the power engagement control program is entered and a speed synchronization command is generated. If the real-time operating parameters are determined not to meet the preset four-wheel drive triggering conditions, the vehicle controller maintains the current vehicle operating mode and continuously collects vehicle operating parameters. Based on the speed synchronization command, the vehicle controller sends a speed synchronization signal to the motor controller. The motor controller adjusts the speed of the auxiliary drive motor to control the relative speed difference between the integrated main reduction gear (1) and the differential housing (3) within ±5 rpm. If it is determined that the relative speed difference is not stable within ±5 rpm or has not reached the set stabilization time, the motor controller continues to adjust the speed of the auxiliary drive motor. The relative speed difference is continuously monitored. When the relative speed difference is determined to be stable within ±5 rpm and reaches the set stabilization time, the vehicle controller outputs an energizing pulse signal to the electromagnetic coil (10) to trigger the electromagnetic coil (10) to be energized and generate electromagnetic thrust. During the axial movement of the electromagnetic thrust-driven push plate (13), the pressure-sensing plate (11) set at the bottom of the reset spring (20) detects the axial pressure value corresponding to the compression of the reset spring (20) in real time, and uses the axial pressure value as a feedback parameter to determine the meshing state of the engagement tooth (17) and the engagement tooth ring (301). According to the feedback parameters, when the axial pressure value detected by the pressure sensor (11) is stable within the preset engagement state pressure threshold range, it is determined that the power transmission route is successfully engaged. Then, the vehicle controller stops outputting energizing pulse signals to the electromagnetic coil (10), and the system enters a zero-power mechanical self-locking state. If the axial pressure value detected by the pressure sensor (11) does not reach the preset engagement state pressure threshold range and the continuous energizing time of the electromagnetic coil (10) does not exceed 120ms, the vehicle controller maintains the energizing of the electromagnetic coil (10) and continuously monitors the axial pressure value. Wherein, the reference axial pressure borne by the reset spring (20) when the engagement tooth (17) is completely in the first high position groove (1402) under the calibrated state is defined as the calibrated value P1, and the pressure threshold range of the engagement state is set to be within 5% of the calibrated value P1. The power disconnection process specifically includes the following steps: When the vehicle operating parameters are determined to meet the preset power disconnection conditions, the vehicle controller sends a signal to the motor controller, and the motor controller controls the output torque of the auxiliary drive motor to perform a torque reduction operation until it drops to 0 Nm. If the vehicle operating parameters are determined not to meet the preset power disconnection conditions, the vehicle controller maintains the four-wheel drive mode and continuously monitors the vehicle operating parameters. After confirming that the output torque of the auxiliary drive motor is zero, the vehicle controller outputs an energizing pulse signal to the electromagnetic coil (10) to generate an electromagnetic thrust that pushes the push plate (13) to the left to release the mechanical self-locking. During the release of the mechanical self-locking, the axial pressure value corresponding to the compression of the reset spring (20) is detected in real time by the pressure sensing plate (11). When the axial pressure value reaches the pressure threshold range of the engagement state, the power transmission route is cut off. Then the vehicle controller stops outputting the energizing pulse signal to the electromagnetic coil (10), and the differential returns to the disconnected mode. If the axial pressure value detected in real time does not reach the pressure threshold range of the engagement state, the vehicle controller maintains the electromagnetic coil (10) energized and continues to detect the axial pressure value.

10. The control method for an electromagnetically disconnected locking differential according to claim 9, characterized in that, The power engagement process also includes a fault-tolerant control program for engagement failures, specifically comprising the following steps: If the continuous energizing time of the electromagnetic coil (10) is detected to exceed 120ms and the feedback parameter still does not reach the pressure threshold range of the engagement state, then the current engagement action is determined to be a failure and the vehicle controller stops outputting the energizing pulse signal. In the event of failure of the engagement action, the relative phase between the integrated main reduction gear (1) and the differential housing (3) is adjusted by ±3°. The adjusted state is then used as the new initial condition. The relative speed difference is monitored again and the power engagement process is repeated.

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