A modular multi-functional transfer case for four-wheel drive vehicles

Abstract

The present invention provides a modular multi-functional transfer case for a four-wheel drive vehicle, which includes a housing and a basic function module disposed within the housing. It further includes an intermediate transmission portion, an electromagnetic dog clutch locking module, and an electromagnetic torque control module disposed within the housing. The basic function control module includes an input portion, a front axle output portion, and a rear axle output portion. The rear axle output portion is drivingly connected to the input portion. The intermediate transmission portion is disposed between the front axle output portion and the rear axle output portion. The electromagnetic dog clutch locking module and the electromagnetic torque control module are respectively disposed on the front axle output portion and are drivingly connected to the rear axle output portion through the intermediate transmission portion. The front axle output portion inputs power under the drive of the electromagnetic dog clutch locking module or the electromagnetic torque control module. Any one of the electromagnetic torque control module or the electromagnetic dog clutch locking module can be deleted according to different vehicle models and configurations without re-developing and designing, thereby significantly shortening the modification cycle and improving the adaptability of the transfer case to vehicle models.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle transfer cases, and relates to a multifunctional transfer case, in particular to a modular multifunctional transfer case for four-wheel drive vehicles. Background Art

[0002] A transfer case is an important device for distributing the power of an engine. In addition to normal road conditions, to meet the driving requirements of vehicles in situations such as intense driving, extremely harsh road conditions with ultra-low adhesion, and extremely poor road conditions where the vehicle requires a large traction force, a combined transfer case needs to be applied in the four-wheel drive system of the vehicle so that the vehicle has the function of timely four-wheel drive or part-time four-wheel drive.

[0003] In existing four-wheel drive systems, to control costs, an electromagnetic torque control module or an electromagnetic dog clutch locking module is often separately installed on the basis of the basic functional module of the transfer case, and an electromagnetic torque control module and an electromagnetic dog clutch locking module are installed simultaneously, so that the vehicle separately has the function of timely four-wheel drive, part-time four-wheel drive, or both timely four-wheel drive and part-time four-wheel drive on the basis of two-wheel drive. For existing transfer cases to match different vehicle models and install different modules, different casings and internal part structures need to be designed, resulting in low vehicle model adaptability of the transfer case and complex vehicle and transfer case development processes. In addition, the existing combined transfer case places the electromagnetic dog clutch locking module on the rear output shaft, resulting in the transfer case requiring a long axial space to achieve functions, a large number of parts, and a large occupied space; moreover, the planetary gear reduction mechanism in the transfer case requires forced lubrication by an oil pump. These designs all lead to too high production costs and maintenance costs of the transfer case. At the same time, the existing transfer case control logic and shifting mechanism are relatively complex, there is a risk of shifting failure, mechanical damage is likely to occur, the shifting execution motor is burned out, and the overall reliability of the transfer case is not high.

[0004] Based on this, it is necessary to provide a transfer case with low cost, small volume, high vehicle model adaptability, and high shifting success rate. Summary of the Invention

[0005] The purpose of the present invention is to provide a modular multifunctional transfer case for four-wheel drive vehicles, so as to solve the technical problems existing in the prior art, such as low vehicle model adaptability of the transfer case, complex development process, large occupied space, high production cost, and mechanical damage and burnout of the shifting execution motor easily occurring during the shifting process.

[0006] To achieve the above purpose, the specific technical solution of the present invention is as follows:

[0007] A modular multi-functional transfer case for a four-wheel drive vehicle, comprising a housing, and a basic function module arranged in the housing. It further includes an intermediate transmission part, an electromagnetic dog clutch locking module, and an electromagnetic torque control module arranged in the housing. The basic function module includes an input part, a front axle output part, and a rear axle output part. The rear axle output part is in transmission connection with the input part. The intermediate transmission part is arranged between the front axle output part and the rear axle output part. The electromagnetic dog clutch locking module and the electromagnetic torque control module are respectively arranged on the front axle output part and are in transmission connection with the rear axle output part through the intermediate transmission part. The front axle output part inputs power under the drive of the electromagnetic dog clutch locking module or the electromagnetic torque control module.

[0008] The input part includes an input shaft, and an input shaft coupling tooth arranged on the input shaft through a spline. The input shaft is arranged in the housing through an input bearing. The input shaft coupling tooth is used for high-speed transmission connection between the input shaft and the rear axle output part;

[0009] The rear axle output part includes a rear output shaft, a shift gear sleeve, a shift fork, a low-speed gear, and a hub and an output shaft gear respectively arranged on the rear output shaft through a spline. The rear output shaft is arranged in the housing through a rear output bearing and is coaxial with the input shaft. The low-speed gear is arranged on the rear output shaft through a needle bearing and is in low-speed transmission connection with the input shaft through the intermediate transmission part. The output shaft gear is in transmission connection with the front axle output part through the intermediate transmission part and is used for driving the front axle output part. The input shaft coupling tooth, the hub, and the low-speed gear are adjacent in sequence. Splines cooperating with the shift gear sleeve are arranged on the input shaft coupling tooth, the hub, and the low-speed gear. The shift gear sleeve is arranged on the outer circumference of the hub through a spline and can slide and mesh relative to the hub, the input shaft coupling tooth, and the low-speed gear. The shift fork is arranged on the shift gear sleeve.

[0010] The intermediate transmission part is arranged between the rear axle output part and the front axle output part, and includes an intermediate shaft, an intermediate coupling tooth, and an intermediate transmission tooth formed on the intermediate shaft. The intermediate shaft is arranged in the housing through an intermediate shaft bearing. The intermediate coupling tooth is arranged at the front end of the intermediate shaft through a needle bearing and is in meshing transmission with the input shaft and the low-speed gear respectively. The intermediate transmission tooth is located at the rear end of the intermediate shaft and is in meshing transmission with the output shaft gear and the front output part.

[0011] The front axle output part includes a front output shaft, a hollow shaft and a front output gear. The front output shaft is arranged in the housing through a deep groove ball bearing. The hollow shaft is sleeved on the front output shaft through a needle bearing. The front output gear is arranged on the hollow shaft through a spline and meshes with an intermediate transmission gear on the intermediate shaft for transmission. The input spline teeth of the electromagnetic dog clutch locking module and the input end of the electromagnetic torque control module are respectively arranged on the hollow shaft through splines.

[0012] The electromagnetic torque control module includes a coupler input housing assembly, an end cover assembly and an electromagnet bracket. The housing assembly and the end cover assembly are connected to each other to form a main module cavity. The electromagnet bracket and the end cover assembly are connected to each other to form a secondary module cavity at one end of the coupler input housing assembly. The other end of the coupler input housing assembly is spline-connected to the hollow shaft.

[0013] An electromagnetic coil A is arranged in the secondary module cavity. A coupler output shaft, a first-stage friction plate group, a second-stage friction plate group, an armature plate, an outer cam and an inner cam are arranged in the main module cavity. The coupler output shaft is sleeved on the front output shaft through a spline. The second-stage friction plate group is arranged between the coupler output shaft and the coupler input housing assembly. Among them, the input end of the second-stage friction plate group is spline-connected to the coupler input housing assembly, and the output end is drivingly connected to the coupler output shaft. The inner cam is adjacent to the coupler output shaft and is respectively arranged on the front output shaft with the outer cam. Opposite sides of the outer cam and the inner cam are correspondingly provided with bidirectional end face spiral grooves, and a transmission steel ball is clamped between the bidirectional end face spiral grooves of the outer cam and the inner cam. The first-stage friction plate group is arranged between the coupler input housing assembly and the outer cam, the input end is spline-connected to the coupler input housing assembly, and the output end is spline-connected to the outer cam. A flat thrust bearing is arranged between the outer cam and the end cover assembly.

[0014] The first-stage friction plate group includes alternately arranged cam outer tooth plates and cam inner tooth plates. The second-stage friction plate group includes alternately arranged outer tooth friction plates and inner tooth friction plates. The cam outer tooth plates and the outer tooth friction plates are respectively spline-connected to the coupler input housing assembly. The cam inner tooth plates are spline-connected to the outer cam. The inner tooth friction plates are spline-connected to the outer side surface of the coupler output shaft.

[0015] The electromagnetic dog clutch locking module includes an outer dog tooth, an inner dog tooth, a dog tooth thrust ring, and an electromagnet housing assembly arranged in sequence. The outer dog tooth is press-fitted on the front output shaft through a spline. The inner dog tooth is arranged on the hollow shaft through a spline and has a degree of freedom to slide relative to the hollow shaft. The electromagnet housing assembly is sleeved on the hollow shaft through an electromagnet support bearing, and there is a gap between the electromagnet housing assembly and the hollow shaft. The dog tooth thrust ring is arranged between the electromagnet housing assembly and the inner dog tooth. An electromagnetic coil B is arranged above the inside of the electromagnet housing assembly, and an electromagnet sliding sleeve assembly is arranged below. The electromagnet housing assembly is open on one side close to the inner dog tooth, and the electromagnet sliding sleeve assembly can axially slide out from the opening of the electromagnet housing assembly. A locking position output piece is arranged on the inner dog tooth.

[0016] A speedometer drive gear for detecting vehicle speed is also arranged on the rear output shaft. The output end of the rear output shaft is installed with a rear output flange through a flange nut A. An oil seal and a dust cover are arranged between the rear output flange and the housing from inside to outside in sequence.

[0017] The output end of the front output shaft is installed with a front output flange through a flange nut B.

[0018] The housing includes a front cover, a middle housing, and a rear housing that are detachably connected in sequence. Among them, the front cover is located on one side of the input part, and the rear housing is located on the output side of the rear shaft output part.

[0019] The beneficial effects of the present invention are as follows: The modular multi-functional transfer case for four-wheel drive vehicles provided by the present invention can significantly improve the success rate of shifting by using an original gear set shifting mechanism, avoid possible mechanical damage during shifting, avoid burning of the shifting motor, and the adopted structure can make the control logic simpler and improve the reliability of the whole machine. The intermediate shaft coupling teeth are floatingly sleeved on the intermediate shaft by using needle bearings, which can not only save space, but also reduce the number of parts used and the manufacturing cost. In addition, since the low-speed gear on the intermediate coupling teeth is larger, it can contact the oil at the bottom of the housing, so splash lubrication can be generated, and it does not require forced lubrication by an oil pump like the planetary gear reduction mechanism of similar products, with lower cost. The housing adopts a three-section design. To match different vehicle models, only the front cover, rear output flange, and front output flange with different sizes need to be remade, and other parts can be shared, further greatly simplifying the development process of the transfer case for different vehicle models and reducing the development cost.

[0020] In addition, in the present invention, the electromagnetic torque control module and the electromagnetic dog clutch locking module are placed on the same axis, realizing the coexistence of four-wheel drive locking and four-wheel drive automatic functions. Moreover, since the electromagnetic dog clutch locking module is placed at the front output shaft instead of the rear output shaft as in similar products, the present invention can achieve the functions in a shorter axial space, thus facilitating the development work for different vehicle models. At the same time, the modular multi-functional transfer case for four-wheel drive vehicles provided by the present invention can delete any one of the electromagnetic torque control module or the electromagnetic dog clutch locking module according to different vehicle models and configurations, or add the other module when only one module is available, without re-developing and designing, thereby significantly shortening the modification cycle and improving the adaptability of the transfer case to vehicle models. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the external structure of the present invention;

[0022] Figure 2 is a schematic diagram of the structure of the present invention;

[0023] Figure 3 is Figure 2 a cross-sectional view taken along the A-A direction in

[0024] Figure 4 is Figure 3 a schematic diagram of the structure of the front axle output part in

[0025] Figure 5 is Figure 4 a partially enlarged schematic diagram of the structure at B in

[0026] Description of the markings in the figure: 1. Input shaft, 2. Sealing plug, 3. Input bearing, 4. Front cover, 5. Middle housing, 6. Input shaft coupling teeth, 7. Shift gear sleeve, 8. Gear hub, 9. Shift fork, 10. Low-speed gear, 11. Output shaft gear, 12. Rear output bearing, 13. Rear output shaft, 14. Speedometer drive gear, 15. Oil seal, 16. Dust cover, 17. Rear output flange, 18. Flange nut A, 19. Intermediate shaft bearing, 20. Rear housing, 21. Electromagnetic dog clutch locking module, 22. Hollow shaft, 23. Front output gear, 24. Electromagnetic torque control module, 26. Front output shaft, 27. Front output flange, 28. Flange nut B, 29. Intermediate coupling teeth, 30. Intermediate shaft, 31. Intermediate shaft thrust washer, 32. Intermediate drive teeth, 2101. External dog teeth, 2102. Internal dog teeth, 2103. Locking position output plate, 2104. Dog tooth thrust ring, 2105. Electromagnetic coil B, 2106. Electromagnet housing assembly, 2107. Electromagnet support bearing, 2108. Electromagnet sliding sleeve assembly, 2401. Coupler input housing assembly, 2402. External tooth friction plate, 2403. Internal tooth friction plate, 2404. Internal cam, 2405. Armature plate, 2406. Cam external tooth plate, 2407. Cam internal tooth plate, 2408. End cover assembly, 2409. Electromagnetic coil A, 2410. Electromagnet bracket, 2411. External cam, 2412. Steel ball, 2413. Coupler output shaft, 2414. Flat thrust bearing, 2601. Deep groove ball bearing. Detailed implementation mode

[0027] To better understand the purpose, structure and function of the present invention, the following will make a further detailed description of the present invention in conjunction with the accompanying drawings.

[0028] As Figures 1 to 3 shown, the present invention provides a modular multi-functional transfer case for four-wheel drive vehicles, including a housing, and a basic function module disposed in the housing for realizing two-wheel drive functions. It further includes an intermediate transmission part and an electromagnetic dog clutch locking module 21 and an electromagnetic torque control module 24 disposed in the housing. Among them, the intermediate transmission part is used for speed reduction and four-wheel drive transmission, the electromagnetic dog clutch locking module 21 is used for realizing four-wheel drive locking function, and the electromagnetic torque control module 24 is used for realizing four-wheel drive automatic function; in addition, the housing is a detachable three-section structure, including a front cover 4, a middle housing 5 and a rear housing 20 connected in sequence. Among them, the front cover 4 is located on one side of the input part, and the rear housing 20 is located on the output side of the rear axle output part. Among them, the above-mentioned basic function module, intermediate transmission part and electromagnetic dog clutch locking module 21 and electromagnetic torque control module 24 are all disposed in the middle housing 5.

[0029] Specifically, the basic functional modules include an input part, a front axle output part, and a rear axle output part. The rear axle output part is in driving connection with the input part. The intermediate transmission part is arranged between the front axle output part and the rear axle output part. The electromagnetic dog clutch locking module 21 and the electromagnetic torque control module 24 are respectively arranged on the front axle output part and are in driving connection with the rear axle output part through the intermediate transmission part. The front axle output part inputs power under the drive of the electromagnetic dog clutch locking module 21 or the electromagnetic torque control module 24.

[0030] The input part includes an input shaft 1 and an input shaft coupling tooth 6 arranged on the input shaft 1 through a spline. The input shaft 1 is arranged in the housing through an input bearing 3. The input shaft coupling tooth 6 is used for driving connection at high speed between the input shaft 1 and the rear axle output part. The rear axle output part includes a rear output shaft 13, a shift gear sleeve 7, a shift fork 9, a low-speed gear 10, and a hub 8 and an output shaft gear 11 respectively arranged on the rear output shaft 13 through splines. The rear output shaft 13 is arranged in the housing through a rear output bearing 12 and is coaxial with the input shaft 1. A sealing plug 2 is arranged between the rear output shaft 13 and the input shaft 1. The low-speed gear 10 is arranged on the rear output shaft 13 through a needle bearing and is in low-speed driving connection with the input shaft 1 through the intermediate transmission part. The output shaft gear 11 is in driving connection with the front axle output part through the intermediate transmission part and is used for driving the front axle output part. The input shaft coupling tooth 6, the hub 8, and the low-speed gear 10 are adjacent in sequence. Splines for cooperating with the shift gear sleeve 7 are arranged on the input shaft coupling tooth 6, the hub 8, and the low-speed gear 10. The shift gear sleeve 7 is arranged on the outer circumference of the hub 8 through a spline and can slide and mesh relative to the hub 8, the input shaft coupling tooth 6, and the low-speed gear 10. The shift fork 9 is arranged on the shift gear sleeve 7.

[0031] The intermediate transmission part is arranged between the rear axle output part and the front axle output part and includes an intermediate shaft 30, an intermediate coupling tooth 29, and an intermediate transmission tooth 32 arranged on the intermediate shaft 30 and integrated with the intermediate shaft 30. The intermediate shaft 30 is arranged in the housing through an intermediate shaft bearing 19. The intermediate coupling tooth 29 is arranged at the front end of the intermediate shaft 30 through a needle bearing and is in meshing transmission with the input shaft 1 and the low-speed gear 10 respectively. An intermediate thrust pad 31 is arranged between the intermediate coupling tooth 29 and the intermediate shaft bearing 19. The intermediate transmission tooth 32 is located at the rear end of the intermediate shaft 30 and is used for meshing transmission between the intermediate shaft 30 and the output shaft gear 11 and the front output gear 23 of the front output part.

[0032] The front axle output part includes a front output shaft 26, a hollow shaft 22 and a front output gear 23. The front output shaft 26 is arranged in the housing through a deep groove ball bearing 2601. The hollow shaft 22 is sleeved on the front output shaft 26 through a needle bearing. The front output gear 23 is arranged on the hollow shaft 22 through a spline and meshes with an intermediate transmission gear 32 for transmission. The input spline teeth of the electromagnetic dog clutch locking module 21 and the input end of the electromagnetic torque control module 24 are respectively arranged on the hollow shaft 22 through splines.

[0033] The electromagnetic torque control module 24 includes a coupler input housing assembly 2401, an end cover assembly 2408 and an electromagnet bracket 2410. The housing assembly and the end cover assembly 2408 are connected to each other to form a main module cavity. The electromagnet bracket 2410 and the end cover assembly 2408 are connected to each other to form a secondary module cavity, which is located at one end of the coupler input housing assembly 2401. The other end of the coupler input housing assembly 2401 is spline-connected to the hollow shaft 22.

[0034] An electromagnetic coil A2409 is arranged in the secondary module cavity. A coupler output shaft 2413, a first-stage friction plate group, a second-stage friction plate group, an armature plate 2405, an outer cam 2411 and an inner cam 2404 are arranged in the main module cavity. The coupler output shaft 2413 is sleeved on the front output shaft 26 through a spline. The second-stage friction plate group is arranged between the coupler output shaft 2413 and the coupler input housing assembly 2401, and includes alternately arranged external tooth friction plates 2402 and internal tooth friction plates 2403. The first-stage friction plate group is arranged between the coupler input housing assembly 2401 and the outer cam 2411, and includes alternately arranged cam external tooth plates 2406 and cam internal tooth plates 2407. The cam external tooth plates 2406 and the external tooth friction plates 2402 are respectively spline-connected to the coupler input housing assembly 2401. The cam internal tooth plates 2407 are spline-connected to the outer cam 2411. The internal tooth friction plates 2403 are spline-connected to the outer side surface of the coupler output shaft 2413. The inner cam 2404 is adjacent to the coupler output shaft 2413 and is respectively arranged on the front output shaft 26 with the outer cam 2411. Opposite side surfaces of the outer cam 2411 and the inner cam 2404 are correspondingly provided with double-sided end face spiral grooves. A transmission steel ball 2412 is clamped between the double-sided end face spiral grooves of the outer cam 2411 and the inner cam 2404. A flat thrust bearing 2414 is arranged between the outer cam 2411 and the end cover assembly 2408.

[0035] Further, the electromagnetic dog clutch locking module 21 includes an external dog tooth 2101, an internal dog tooth 2102, a dog tooth thrust ring 2104 and an electromagnet housing assembly 2106 arranged in sequence. The external dog tooth 2101 is arranged on the front output shaft 26 by interference fit of splines. The internal dog tooth 2102 is arranged on the hollow shaft 22 by splines and has the freedom to slide relative to the hollow shaft 22. The electromagnet housing assembly 2106 is sleeved on the hollow shaft 22 through an electromagnet support bearing 2107 and there is a gap between it and the hollow shaft 22. The dog tooth thrust ring 2104 is arranged between the electromagnet housing assembly 2106 and the internal dog tooth 2102. An electromagnetic coil B 2105 is arranged above the interior of the electromagnet housing assembly 2106, and an electromagnet sliding sleeve assembly 2108 is arranged below. One side of the electromagnet housing assembly 2106 close to the internal dog tooth is open, and the electromagnet sliding sleeve assembly 2108 can axially slide out from the opening of the electromagnet housing assembly 2106. A locking position output piece 2103 is arranged on the internal dog tooth 2102.

[0036] A speedometer drive gear 14 for detecting vehicle speed is further arranged on the rear output shaft 13. The output end of the rear output shaft 13 is installed with a rear output flange 17 through a flange nut A 18 for outputting power to the vehicle's rear drive shaft. An oil seal 15 and a dust cover 16 are arranged between the rear output flange 17 and the housing from inside to outside for lubricating the internal parts of the housing and dust-proofing the internal components of the housing. The output end of the front output shaft 26 is installed with a front output flange 27 through a flange nut B 28 for outputting power to the vehicle's front drive shaft.

[0037] In this embodiment, an electromagnetic dog clutch locking module 21 and an electromagnetic torque control module 24 are arranged in the housing at the same time, so that the transfer case has six working modes: high-speed two-wheel drive, high-speed four-wheel drive automatic, high-speed four-wheel drive lock-up, low-speed two-wheel drive, low-speed four-wheel drive automatic, and low-speed four-wheel drive lock-up. Among them, in order to achieve the above working modes, in this embodiment, a high and low speed shift motor (hereinafter referred to as the shift motor) and a transfer case controller need to be installed outside the housing. The transfer case controller is built-in with a single-chip microcomputer, which can communicate with the vehicle bus to collect relevant vehicle data and at the same time feedback its own working status to the vehicle bus.

[0038] As Figures 3 to 5 shown, in this embodiment, the action principle in different working modes is as follows:

[0039] 1. High-speed two-wheel drive: This is the energy-saving mode of the vehicle. When shifting to the high-speed two-wheel drive mode, as Figure 3As shown in the figure, the shift motor moves the shift sleeve 7 to the left through the shift mechanism, so that while it is splined with the gear hub 8, it is also splined with the input shaft coupling tooth 6, completing the high-speed gear shift. The power output by the transmission is transmitted to the input shaft coupling tooth 6 splined to the input shaft 1 through the input shaft 1, and then transmitted to the shift sleeve 7. The shift sleeve 7 drives the rear output shaft 13 splined to the gear hub 8 to rotate, and the rear output shaft 13 outputs the power to the rear output flange 17, thereby outputting power to the vehicle's rear drive shaft;

[0040] 2. High-speed four-wheel drive automatic: This mode is suitable for driving on the road during intense driving or on roads with low adhesion. In this mode, the electromagnetic torque control module 24 participates in the work. The transfer case controller communicates with the vehicle bus, collects necessary driving data, and adjusts the supply current of the electromagnetic torque control module 24 in real time according to the built-in logic and algorithm, thereby adjusting the pressing force of the friction plate group inside the module to controllably distribute the power to the front output shaft 26, enabling the vehicle to obtain ideal front-wheel driving force and achieving a significant improvement in the vehicle's driving performance.

[0041] As Figure 3 , Figure 4 , Figure 5 As shown in the figure, the shift motor moves the shift sleeve 7 to the left through the shift mechanism, so that while it is splined with the gear hub 8, it is also splined with the input shaft coupling tooth 6, completing the high-speed gear shift. In addition to the power being transmitted to the rear output shaft 13 as described in the previous high-speed two-wheel drive, it is also transmitted to the intermediate shaft 30 through the output shaft gear 11 splined to the rear output shaft 13, and transmitted to the front output gear 23 through the intermediate drive tooth 32 on the intermediate shaft 30. The front output gear 23 transmits the power to the hollow shaft 22, so that the input end of the electromagnetic torque control module 24 inputs power driven by the hollow shaft 22. At this time, the transfer case controller communicates with the vehicle bus and adjusts the supply current to the electromagnetic torque control module 24 in real time to adjust the pressing force of the friction plate group inside the module, thereby controllably distributing the power to the front output shaft 26. The power of the front output shaft 26 is transmitted to the vehicle's front drive shaft through the front output flange 27, thereby achieving timely high-speed four-wheel drive, that is, high-speed four-wheel drive automatic.

[0042] 3. High-speed four-wheel drive lock: This mode is suitable for driving on extremely harsh road conditions with extremely low adhesion, such as muddy roads, deserts, super-slippery ice and snow roads, etc. In this mode, the electromagnetic dog clutch lock module 21 participates in the work and combines with the front output shaft 26, and the transfer case is rigidly locked to achieve four-wheel drive.

[0043] As Figure 3 , Figure 4As shown in the figure, the shift motor moves the shift sleeve 7 to the left through the shift mechanism, so that while it is spline-fitted with the gear hub 8, it is also spline-fitted with the input shaft coupling tooth 6, completing the high-speed gear shift. After the electromagnet of the electromagnetic dog clutch locking module 21 is energized, it pushes the internal dog tooth 2102 to engage with the external dog tooth 2101. In addition to the power being transmitted to the rear output shaft 13 as described in the above high-speed two-wheel drive, the power is also transmitted to the intermediate shaft 30 through the output gear spline-connected to the rear output shaft 13, and then transmitted to the front output gear 23 through the intermediate drive tooth 32 of the intermediate shaft 30. The front output gear 23 transmits the power to the hollow shaft 22, so as to reach the internal dog tooth 2102 arranged on the hollow shaft 22 through splines. The internal dog tooth 2102 transmits the power to the front output shaft 26 spline-fitted with the external dog tooth 2101 through the engaged external dog tooth 2101. The power of the front output shaft 26 is transmitted to the front drive shaft of the vehicle through the front output flange 27, thus realizing forced high-speed four-wheel drive, that is, high-speed four-wheel drive locking.

[0044] 4. Low-speed two-wheel drive: This mode is suitable for driving on steep and winding slopes with good adhesion. In this mode, the vehicle has both a large driving torque and the flexibility of front-wheel steering.

[0045] As Figure 3 shown in the figure, the shift motor moves the shift sleeve 7 to the right through the shift mechanism, so that while it is spline-fitted with the gear hub 8, it is also spline-fitted with the low-speed gear 10, completing the low-speed gear shift. The power output by the transmission is transmitted to the intermediate connecting tooth 29 through the input shaft 1. After the first-stage deceleration, it is then transmitted to the low-speed gear 10 to complete the second-stage deceleration. Then, the power is transmitted to the gear hub 8 spline-connected to it through the shift sleeve 7, and is transmitted to the rear output flange 17 through the rear output shaft 13 spline-connected to the gear hub 8, outputting power to the rear drive shaft of the vehicle. At this time, the vehicle is in low-speed rear-wheel drive, and the torque of the rear output shaft 13 of the transfer case is amplified. The amplification factor can be obtained by adjusting the number of teeth of the relevant gears. In this embodiment, it is amplified by 3.64 times.

[0046] 5. Low-speed four-wheel drive automatic: This mode is suitable for driving on roads with poor ground adhesion and requiring large traction and a certain degree of steering flexibility.

[0047] As Figures 3 to 5As shown in the figure, the shift motor moves the shift sleeve 7 to the right through the shift mechanism, so that while it is spline-fitted with the gear hub 8, it is also spline-fitted with the low-speed gear 10 to complete the low-speed gear shift. In addition to the power being transmitted to the rear output shaft 13 as described in the previous low-speed two-wheel drive, the power is also transmitted to the intermediate shaft 30 through the output gear spline-connected to the output shaft. After the power passes through the intermediate drive gear 32 and the front output gear 23 and reaches the hollow shaft 22, it is transmitted to the input end of the electromagnetic torque control module 24 through splines. At this time, the transfer case controller communicates with the vehicle bus to collect the necessary driving data of the vehicle and adjusts the supply current to the electromagnetic torque control module 24 in real time to adjust the pressing force of the friction plate group inside the module, so as to controllably distribute the power to the front output shaft 26. The power of the front output shaft 26 is transmitted to the front drive shaft of the vehicle through the front output flange 27, thus realizing automatic low-speed four-wheel drive.

[0048] 6. Low-speed four-wheel drive lock: This mode is suitable for driving on roads with extremely poor road conditions, where the vehicle requires a large traction force and does not require flexible steering. In this mode, the electromagnetic dog clutch lock module 21 participates in the work and combines with the front output shaft 26, and the transfer case is rigidly locked to achieve four-wheel drive.

[0049] As Figure 3 , Figure 4 shown in the figure, the shift motor moves the shift sleeve 7 to the right through the shift mechanism, so that while it is spline-fitted with the gear hub 8, it is also spline-fitted with the low-speed gear 10 to complete the low-speed gear shift. After the electromagnet of the electromagnetic dog clutch lock module 21 is energized, it pushes the inner dog teeth 2102 to mesh with the outer dog teeth 2101. In addition to the power being transmitted to the rear output shaft 13 as described in the previous low-speed two-wheel drive, the power is also transmitted to the intermediate shaft 30 through the output gear spline-connected to the rear output shaft 13. After passing through the intermediate drive gear 32 on the intermediate shaft 30, it is transmitted to the front output gear 23, and the front output gear 23 transmits the power to the hollow shaft 22, so that the inner dog teeth 2102 arranged on the hollow shaft 22 through splines, and the inner dog teeth 2102 transmit the power to the front output shaft 26 spline-fitted with the outer dog teeth 2101 through the meshing outer dog teeth 2101. The power of the front output shaft 26 is transmitted to the front drive shaft of the vehicle through the front output flange 27, realizing forced low-speed four-wheel drive, that is, low-speed four-wheel drive lock.

[0050] In the above working mode, the working principle of the electromagnetic torque control module 24 is as follows:

[0051] As Figure 4 , Figure 5As shown in the figure, when four-wheel drive is selected, power is transmitted through the front output gear 23 to the hollow shaft 22 splined thereto, driving the coupler input housing assembly 2401 of the electromagnetic torque control module 24 splined to the hollow shaft 22 to obtain power. The coupler input housing assembly 2401 drives several cam outer teeth 2406 that are splined thereto to rotate.

[0052] At this time, if the electromagnetic coil A 2409 is energized, a large magnetic force will be generated on the right end face of the end cover assembly 2408. The magnetic force passes through the first-stage friction plate group composed of several cam outer teeth 2406 and several cam inner teeth 2407, pulling the armature plate 2405 to move to the left and pressing the first-stage friction plate group. After the first-stage friction plate group is pressed, the cam outer teeth 2406 drive the cam inner teeth 2407 to rotate together under the action of friction. The outer cam 2411 splined thereto rotates together with the rotation of the cam inner teeth 2407. In this embodiment, 6 bidirectional end face spiral grooves are provided on the right end face of the outer cam 2411. Correspondingly, 6 bidirectional end face spiral grooves corresponding to the outer cam 2411 are also provided on the left end face of the inner cam 2404, and 6 steel balls 2412 are clamped between them. The rotation of the outer cam 2411 drives the 6 steel balls 2412 to rise along the end face spiral grooves. Blocked by the end cover assembly 2408 and the flat thrust bearing 2414, the outer cam 2411 cannot move to the left. At this time, under the action of the steel balls 2412, the inner cam 2404 is driven to slide to the right and press the second-stage friction plate group composed of several outer tooth friction plates 2402 and several inner tooth friction plates 2403. After the second-stage friction plate group is pressed, the outer tooth friction plates 2402 drive the inner tooth friction plates 2403 to rotate together under the action of friction. After the coupler output shaft 2413 splined thereto obtains power, it transmits the power to the front output shaft 26 splined thereto. Finally, the power is output through the front output shaft 26 and to the vehicle's front drive shaft. The transfer case controller controls the magnitude of the current supplied to the electromagnetic coil A 2409, so that the first-stage friction plate group obtains different pressures, thereby transmitting a controllable torque to the front output shaft 26.

[0053] The working principle of the electromagnetic dog clutch locking module 21 is as follows:

[0054] The on-off of the electromagnetic coil B 2105 of this module is also controlled by the transfer case controller.

[0055] Such as Figure 4As shown, when four-wheel drive lock is selected, power is transmitted through the front output gear 23 to the hollow shaft 22 which is spline-connected thereto. The internal spline teeth 2102 are sleeved on the hollow shaft 22 through splines and can axially slide relative to the hollow shaft 22; the external spline teeth 2101 are press-fitted on the front output shaft 26 through splines with interference fit. The transfer case controller controls the electromagnetic coil B2105 to be energized, and the electromagnet housing assembly 2106 composed of bimetallic materials generates a thrust force, pushing the electromagnet sliding sleeve assembly 2108 to slide to the right, pushing the spline tooth thrust ring 2104 and the internal spline teeth 2102 to slide to the right, so that the spline teeth at the right end face of the internal spline teeth 2102 are engaged with the spline teeth at the left end face of the external spline teeth 2101. At this time, power is transmitted from the hollow shaft 22 through the internal spline teeth 2102 to the external spline teeth 2101, and after being transmitted to the front output shaft 26, it is finally output to the front drive shaft of the vehicle.

[0056] A lock position output piece 2103 is arranged on the internal spline teeth 2102. It moves together with the internal spline teeth 2102, transmits position information to the sensor arranged on the rear housing 20, and reports it to the vehicle bus through the transfer case controller.

[0057] It can be understood that the present invention is described through some embodiments. Those skilled in the art know that without departing from the spirit and scope of the present invention, various changes or equivalent replacements can be made to these features and embodiments. In addition, under the teaching of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present invention.

Claims

1. A modular multi-functional transfer case for a four-wheel drive vehicle, comprising a housing and basic functional modules arranged in the housing, characterized in that: It further includes an intermediate transmission part, an electromagnetic dog clutch locking module (21) and an electromagnetic torque control module (24) arranged inside the housing. The basic function module includes an input part, a front axle output part and a rear axle output part. The rear axle output part is in transmission connection with the input part. The intermediate transmission part is arranged between the front axle output part and the rear axle output part. The electromagnetic dog clutch locking module (21) and the electromagnetic torque control module (24) are respectively arranged on the front axle output part and are in transmission connection with the rear axle output part through the intermediate transmission part. The front axle output part inputs power under the drive of the electromagnetic dog clutch locking module (21) or the electromagnetic torque control module (24). The front axle output part includes a front output shaft (26), a hollow shaft (22) and a front output gear (23). The hollow shaft (22) is sleeved on the front output shaft (26) through a needle bearing. The electromagnetic torque control module (24) includes a coupler input housing assembly (2401), an end cover assembly (2408) and an electromagnet bracket (2410). The housing assembly and the end cover assembly (2408) are connected to each other to form a main module cavity. The electromagnet bracket (2410) and the end cover assembly (2408) are connected to each other to form a secondary module cavity at one end of the coupler input housing assembly (2401). The other end of the coupler input housing assembly (2401) is in spline connection with the hollow shaft (22). An electromagnetic coil A (2409) is arranged in the secondary module cavity. A coupler output shaft (2413), a first-stage friction plate group, a second-stage friction plate group, an armature plate (2405), an outer cam (2411) and an inner cam (2404) are arranged in the main module cavity. The coupler output shaft (2413) is sleeved on the front output shaft (26) through splines. The second-stage friction plate group is arranged between the coupler output shaft (2413) and the coupler input housing assembly (2401). Among them, the input end of the second-stage friction plate group is in spline connection with the coupler input housing assembly (2401), and the output end is in transmission connection with the coupler output shaft (2413). The inner cam (2404) is adjacent to the coupler output shaft (2413) and is respectively arranged on the front output shaft (26) with the outer cam (2411). Opposite side surfaces of the outer cam (2411) and the inner cam (2404) are correspondingly provided with bidirectional end face spiral grooves. Transmission steel balls (2412) are clamped between the bidirectional end face spiral grooves of the outer cam (2411) and the inner cam (2404). The first-stage friction plate group is arranged between the coupler input housing assembly (2401) and the outer cam (2411), with the input end in spline connection with the coupler input housing assembly (2401) and the output end in spline connection with the outer cam (2411). A flat thrust bearing (2414) is arranged between the outer cam (2411) and the end cover assembly (2408). The output end of the front output shaft (26) is installed with a front output flange (27) through a flange nut B (28).

2. The modular multi-functional transfer case for a four-wheel drive vehicle according to claim 1, characterized in that: The input part includes an input shaft (1) and an input shaft coupling gear (6) arranged on the input shaft (1) through splines. The input shaft (1) is arranged in the housing through an input bearing (3). The input shaft coupling gear (6) is used for high-speed transmission connection between the input shaft (1) and the rear shaft output part. The rear shaft output part includes a rear output shaft (13), a shift gear sleeve (7), a shift fork (9), a low-speed gear (10), and a hub (8) and an output shaft gear (11) respectively arranged on the rear output shaft (13) through splines. The rear output shaft (13) is arranged in the housing through a rear output bearing (12) and is coaxial with the input shaft (1). The low-speed gear (10) is arranged on the rear output shaft (13) through a needle bearing and is in low-speed transmission connection with the input shaft (1) through an intermediate transmission part. The output shaft gear (11) is in transmission connection with the front shaft output part through an intermediate transmission part and is used for driving the front shaft output part. The input shaft coupling gear (6), the hub (8), and the low-speed gear (10) are adjacent to each other in sequence. Splines for cooperating with the shift gear sleeve (7) are arranged on the input shaft coupling gear (6), the hub (8), and the low-speed gear (10). The shift gear sleeve (7) is arranged on the outer circumference of the hub (8) through splines and can slide and engage relative to the hub (8), the input shaft coupling gear (6), and the low-speed gear (10). The shift fork (9) is arranged on the shift gear sleeve (7).

3. The modular multi-functional transfer case for a four-wheel drive vehicle according to claim 2, characterized in that: The intermediate transmission part is arranged between the rear shaft output part and the front shaft output part and includes an intermediate shaft (30), an intermediate coupling gear (29), and an intermediate transmission gear (32) formed on the intermediate shaft (30). The intermediate shaft (30) is arranged in the housing through an intermediate shaft bearing (19). The intermediate coupling gear (29) is arranged at the front end of the intermediate shaft (30) through a needle bearing and is in meshing transmission with the input shaft (1) and the low-speed gear (10) respectively. The intermediate transmission gear (32) is arranged at the rear end of the intermediate shaft (30) and is in meshing transmission with the output shaft gear (11) and the front output part.

4. The modular multi-functional transfer case for a four-wheel drive vehicle according to claim 2, characterized in that: The front output shaft (26) is arranged in the housing through a deep groove ball bearing (2601). The front output gear (23) is arranged on the hollow shaft (22) through splines and is in meshing transmission with the intermediate transmission part. The input spline teeth of the electromagnetic dog clutch locking module (21) and the input end of the electromagnetic torque control module (24) are respectively arranged on the hollow shaft (22) through splines.

5. A modular multi-functional transfer case for a four-wheel drive vehicle according to claim 1, characterized in that: The first-stage friction plate group includes alternately arranged cam outer toothed plates (2406) and cam inner toothed plates (2407). The second-stage friction plate group includes alternately arranged outer toothed friction plates (2402) and inner toothed friction plates (2403). The cam outer toothed plates (2406) and the outer toothed friction plates (2402) are respectively splined to the coupler input housing assembly (2401). The cam inner toothed plates (2407) are splined to the outer cam (2411). The inner toothed friction plates (2403) are splined to the outer side of the coupler output shaft (2413).

6. The modular multi-functional transfer case for a four-wheel drive vehicle according to claim 4, wherein: The electromagnetic dog clutch locking module (21) includes successively arranged outer dog teeth (2101), inner dog teeth (2102), a dog tooth thrust ring (2104), and an electromagnet housing assembly (2106). The outer dog teeth (2101) are press-fitted onto the front output shaft (26) by splines. The inner dog teeth (2102) are splined onto the hollow shaft (22) and have the freedom to slide relative to the hollow shaft (22). The electromagnet housing assembly (2106) is sleeved onto the hollow shaft (22) through an electromagnet support bearing (2107) and has a gap with the hollow shaft (22). The dog tooth thrust ring (2104) is arranged between the electromagnet housing assembly (2106) and the inner dog teeth (2102). An electromagnetic coil B (2105) is arranged above the interior of the electromagnet housing assembly (2106), and an electromagnet sliding sleeve assembly (2108) is arranged below. The electromagnet housing assembly (2106) is open on the side close to the inner dog teeth. The electromagnet sliding sleeve assembly (2108) can axially slide out from the opening of the electromagnet housing assembly (2106). A locking position output piece (2103) is arranged on the inner dog teeth (2102).

7. The modular multi-functional transfer case for a four-wheel drive vehicle according to claim 2, characterized in that: A speedometer drive gear (14) for detecting vehicle speed is also arranged on the rear output shaft (13). The output end of the rear output shaft (13) is installed with a rear output flange (17) through a flange nut A (18). An oil seal (15) and a dust cover (16) are successively arranged between the rear output flange (17) and the housing from the inside to the outside.

8. A modular multi-functional transfer case for a four-wheel drive vehicle according to claim 1, characterized in that: The housing includes a front cover (4), a middle housing (5), and a rear housing (20) that are successively detachably connected. Among them, the front cover (4) is located on the side of the input part, and the rear housing (20) is located on the output side of the rear shaft output part.

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