Two-speed hub integrated electric drive wheel set and vehicle including the electric wheel set

Abstract

The present invention discloses a two-speed hub-integrated electric drive wheel assembly and a vehicle incorporating the same. The electric drive wheel assembly comprises a front housing, a middle housing I, a middle housing II, a rear housing, a high-speed drive motor, a fixed-axis gear train reduction mechanism, a first planetary gear train reduction mechanism, a second planetary gear train reduction mechanism, a shift mechanism, a shift drive mechanism, a transition flange, an upper suspension arm support, a lower suspension arm support, a brake system, and a wheel rim. The present invention integrates the entire electric drive system into the wheel hub, significantly improving vehicle space utilization, enabling more flexible vehicle layout, a more compact structure, and improved transmission efficiency. Furthermore, the vehicle provided by the present invention can achieve different transmission ratios by adjusting the different meshing relationships between the shift mechanism and the planetary gear train reduction mechanism, thereby driving the vehicle at different speed ratios to meet complex and diverse driving needs.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive wheelsets, and in particular to a two-speed hub-integrated electric drive wheelset and a vehicle comprising the electric wheel set. Background Art

[0002] In recent years, new energy vehicles have experienced rapid development driven by the global push for energy conservation and emissions reduction. Currently, new energy vehicles are primarily powered by electricity, with two main drive modes: central drive and distributed drive. Central drive has a single power source, a more complex transmission system, and a higher curb weight. Distributed drive, on the other hand, integrates the electric motor, reducer mechanism, and wheel hub into the wheel, eliminating the clutch, transmission system, and mechanical differential found in traditional central drive systems. This simplifies the mechanical transmission structure and reduces vehicle weight. Furthermore, distributed drive takes up less space, and each wheel is driven by an independent motor, making it more flexible.

[0003] Distributed in-wheel electric drive vehicles are usually equipped with a single-speed ratio reducer, which usually performs poorly in the face of complex and diverse terrain conditions, especially for all-terrain vehicles, off-road vehicles and other vehicles that need to pass through various complex road conditions. This single-speed ratio reducer often cannot meet the driving requirements of such vehicles with high performance requirements. For example, when the vehicle is traveling on a road with a large slope, a low-speed, high-torque reducer is required, and when the vehicle requires a higher driving speed, a high-speed, low-torque reducer is required; in addition, a single-speed ratio reducer cannot keep the drive motor within a relatively ideal operating characteristic range.

[0004] The patented "Two-speed hub motor drive device" (application number: CN201610842890.X) provides a method for switching between the reverse gear, neutral gear and high gear by reciprocating the gear sleeve along the axial direction. However, the disadvantages of the gear sleeve arrangement in this structure are: (1) The structural diagram shows that the gear sleeve occupies a large space in the wheel rim, and its radial and axial dimensions are large, which will increase the mass of the structure and fail to achieve the design principle of lightweight structure; (2) The shift mechanism is combined with the last stage planetary gear system to jointly realize the high and low speed modes. The driving force output by the driving motor will generate a large torque after being amplified by the first two stages of planetary deceleration. This method will cause a large shift impact on the shift coupling teeth during the shift process, thereby shortening their service life.

[0005] The published patent "A dual-reduction drive device for electric vehicles" (application number: CN202020551939.8) provides a hub motor with a planetary reduction mechanism. However, the motor rotor in this structure is always in rotation, which will affect the layout of the shift drive rod.

[0006] It can be seen that the layout of distributed wheel hubs, which can achieve compact and lightweight layout while ensuring high-efficiency operation of motors under different road conditions and improving vehicle power economy and strength reliability, still needs to be improved. Summary of the Invention

[0007] In order to overcome the shortcomings of the prior art, the present invention provides a two-speed hub-integrated electric drive wheel set and a vehicle including the electric wheel set. The technical solution of the present invention is as follows:

[0008] As a first aspect of the present invention, there is provided a two-speed hub-integrated electric drive wheel set, comprising a front housing, a middle housing I, a middle housing II, a rear housing, a drive motor, a fixed-axis gear train reduction mechanism, a first planetary gear train reduction mechanism, a second planetary gear train reduction mechanism, a shift mechanism, a transition flange, and a rim;

[0009] The drive motor, front housing, and middle housing I are located outside the wheel rim, forming an integrated structure with the front housing. One end of the middle housing II is connected to the middle housing I, while the other end passes through the wheel rim and connects to the rear housing. The front housing, middle housing I, middle housing II, and rear housing are sequentially connected, with toe joints provided at the connection points between adjacent housings to ensure the transmission accuracy requirements of the coaxial arrangement of the transmission mechanism. The output shaft of the drive motor is connected to the input shaft of the fixed-axis gear train reduction mechanism. The output power of the high-speed drive motor is transmitted to the wheel in sequence through the fixed-axis gear train reduction mechanism, the first planetary gear train reduction mechanism, the second planetary gear train reduction mechanism, the transition flange, and the wheel rim.

[0010] The shift mechanism is arranged between the first planetary gear train reduction mechanism and the second planetary gear train reduction mechanism;

[0011] The first planetary gear train reduction mechanism includes a first sun gear, a first planet gear, a first planet shaft, a first ring gear, a first inner planet carrier, a first outer planet carrier and a ring gear support;

[0012] The shift mechanism includes a fixed bracket, an engagement sleeve, a first spline hub, and a second spline hub. The shift mechanism cooperates with the coupling teeth of the ring gear bracket and the coupling teeth of the first outer planetary carrier in the first planetary gear train reduction mechanism to transmit power. The ring gear bracket of the first planetary gear train reduction mechanism is supported on the fixed bracket in the shift mechanism by two angular contact ball bearings. The fixed bracket is provided with a boss as a shoulder of the two angular contact ball bearings. The engagement sleeve is provided on the periphery of the fixed bracket and the first spline hub. The fixed bracket in the shift mechanism is fixedly connected to the middle section housing I and is provided with a spline that is matched with the teeth of the engagement sleeve. The first spline hub and the second spline hub are axially fixed to the ring gear bracket and the first outer planetary carrier respectively by a retaining spring. The inner ring spline of the first spline hub is matched with the coupling teeth of the ring gear bracket, and the inner ring spline of the second spline hub is matched with the coupling teeth of the first outer planetary carrier. The outer ring splines of the fixed bracket, the first spline hub, and the second spline hub are all matched with the coupling teeth of the engagement sleeve.

[0013] In the structure provided by the present invention, the shift drive system and the power transmission system are arranged coaxially, which increases the compactness of the overall structure in the axial direction. At the same time, the coupling sleeve provided by the present invention is arranged at the central axis of the first outer planetary carrier, and the radial and axial dimensions of the shift coupling sleeve are small, which not only makes the structure more compact and facilitates the arrangement of other components, but also enhances the torsional resistance and structural strength of the shift mechanism.

[0014] Preferably, the fixed-axis gear train reduction mechanism includes a high-speed gear shaft, a low-speed gear and a low-speed gear shaft. The high-speed gear shaft is fixedly connected to the output shaft of the drive motor, and the low-speed gear is arranged on the periphery of one end of the low-speed gear shaft. The outer teeth of the high-speed gear shaft and the low-speed gear are engaged with each other to transmit power to the low-speed gear shaft; the high-speed gear shaft and the low-speed gear are respectively arranged at the connection positions of the front end housing and the middle section housing I, and are supported by deep groove ball bearings, which can ensure the transmission accuracy of the fixed-axis gear train.

[0015] Preferably, in the first planetary gear train reduction mechanism, the inner ring of the first sun gear is provided with an internal spline, which is connected to the low-speed gear shaft, and the outer ring is meshed with the first planet gear. The first planet gear is loosely sleeved on the first planet shaft through a needle bearing and rotates relative to the first planet shaft. The first inner planet carrier and the first outer planet carrier are both provided with holes that cooperate with the first planet shaft. The two ends of the first planet shaft are supported in the holes that cooperate with the first outer planet carrier and the first inner planet carrier by interference fit and clearance fit, respectively. The first inner planet carrier and the first outer planet carrier are respectively supported on the middle section housing I and the second outer planet carrier of the second planetary gear train reduction mechanism through tapered roller bearings. In addition, in order to reduce the wear between the two ends of the first sun gear and the first planet gear and the first inner planet carrier and the first outer planet carrier during the meshing movement, gaskets with higher hardness after heat treatment are respectively provided between the first sun gear, the first planet gear and the first inner planet carrier and the first outer planet carrier. The first ring gear is meshed with the first planetary gear and the ring gear bracket through meshing teeth respectively. The height of the engaging teeth on the first ring gear with the first planetary gear is greater than the height of the engaging teeth with the ring gear bracket. The height difference of the engaging teeth on the first ring gear can play a role in shaft shoulder positioning, and cooperate with the retaining spring to axially fix the ring gear bracket to the first ring gear. The ring gear bracket and the first outer planetary carrier are respectively provided with engaging teeth that cooperate with the shift mechanism.

[0016] Preferably, the second planetary gear train reduction mechanism includes: a second sun gear, second planetary gears, a second planetary shaft, a second ring gear, a second inner planetary carrier, and a second outer planetary carrier. The inner ring of the second sun gear is provided with an internal spline and connected to the first outer planetary carrier, while the outer ring meshes with the second planetary gear. The second planetary gear is loosely mounted on the second planetary shaft via a needle roller bearing and rotates relative to the second planetary shaft. The second inner planetary carrier and the second outer planetary carrier both have holes that mate with the second planetary shaft. The ends of the second planetary shaft are supported in the mating holes of the second outer planetary carrier and the second inner planetary carrier, respectively, through interference and clearance fits. The second inner planetary carrier and the second outer planetary carrier are supported on the middle housing II and the rear housing, respectively, via tapered roller bearings. In addition, to reduce wear between the ends of the second sun gear and the second planetary gear and the second inner planetary carrier and the second outer planetary carrier during meshing, heat-treated high-hardness gaskets are provided between the second sun gear, the second planetary gear, and the second inner planetary carrier and the second outer planetary carrier, respectively. Furthermore, in order to comply with the principles of high transmission efficiency, small size, light weight and easy manufacturing, the gear transmission types in the first planetary gear train reduction mechanism and the second planetary gear train reduction mechanism are both NGW type.

[0017] Preferably, the shift mechanism is provided between the first planetary gear train reduction mechanism and the second planetary gear train reduction mechanism, and the outer surface of the engagement sleeve is I-shaped.

[0018] Specifically, at the spline matching position between the engagement sleeve and the fixed bracket and the second spline hub in the shift mechanism, large chamfers are provided at both ends of the spline, thereby ensuring that the engagement sleeve can slide smoothly to the fixed bracket or the second spline hub.

[0019] The width of the engagement sleeve is smaller than the width of the outer ring spline engaging teeth in the first spline hub.

[0020] Preferably, the two-speed hub-integrated electric drive wheel set provided by the present invention further includes a shift drive mechanism, which includes: a shift fork, a bevel gear shift fork shaft, a driving bevel gear shaft, a drive device, and an oil seal seat. The bevel gear shift fork shaft and the driving bevel gear shaft are respectively supported in the middle section housing II through angular contact ball bearings. The shift fork is clamped in the middle of the I-shaped outer surface of the engagement sleeve. The bevel gear shift fork shaft and the driving bevel gear shaft are meshed and driven by a bevel gear structure. The bevel gear shift fork shaft passes through the shift fork. The shift fork and the bevel gear shift fork shaft are both provided with rectangular or trapezoidal transmission threads at the contact position to realize transmission. The driving device is connected to the active bevel gear shaft to provide rotational power for the active bevel gear shaft. The active bevel gear shaft passes through the oil seal seat fixed to the middle section housing II through a threaded structure. The output power of the driving device is transmitted to the threaded matching position of the bevel gear shift fork shaft and the shift fork after the bevel gears between the active bevel gear shaft and the bevel gear shift fork shaft engage and reverse. The power drives the bevel gear shift fork shaft to rotate under the action of the angular contact ball bearing, and then relies on the mutual force between the rectangular or trapezoidal threads at the matching position to drive the shift fork to move relative to the bevel gear shift fork shaft, thereby driving the engagement sleeve of the shift mechanism to reciprocate.

[0021] The driving mode of the driving device in the shift drive mechanism is electric or electromagnetic. The driving bevel gear shaft is provided with an external spline at the other end of the bevel gear, which cooperates with the internal spline of the driving device to realize power transmission.

[0022] Furthermore, the present invention includes a vehicle controller (VCU), which is individually connected to the drive motors of each wheel. The VCU sends different torque signals to the four drive motors. Normally, the electric wheel assembly operates in high gear and only switches to low gear when insufficient torque is encountered.

[0023] In addition, in order to avoid the collision impact of the engaging teeth caused by the high speed difference during the gear shifting process, the driving device coordinates with the driving motor. That is, when the driving device drives the engaging sleeve to slide to the neutral position, the driving motor quickly adjusts the speed according to the speed of the engaging sleeve, so that the speed difference of the engaging teeth is minimized, thereby achieving gear shifting.

[0024] Preferably, the gear shift drive device is a servo motor or a stepper motor.

[0025] Specifically, oil seals are installed between the front housing and the high-speed gear shaft, between the middle housing II and the driving bevel gear shaft, and between the rear housing and the second outer planetary carrier. To maintain stable air pressure within the wheelset, a vent plug is installed in the middle housing I.

[0026] Preferably, the two-speed hub-integrated electric drive wheel assembly provided herein also includes a braking system comprising a brake caliper and a brake disc, the brake caliper being fixedly connected to the rear end housing. A transition flange is fixedly connected to the brake disc and the wheel rim. To ensure coaxiality between the wheel and the transmission system, the transition flange is provided with a toe that mates with the wheel rim. The conical interference fit between the transition flange and the second outer planetary carrier is achieved by pre-tightening studs and hexagonal flange nuts.

[0027] As a second aspect of the present invention, a vehicle comprising the two-speed hub integrated electric drive wheel set is also provided, wherein the two-speed hub integrated electric drive wheel set is connected to the vehicle frame via a suspension upper swing arm support fixed to the upper end of the middle section shell I and a suspension lower swing arm support fixed to the lower end of the middle section shell I.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The present invention integrates the power system, transmission system, and braking system into the wheel hub, and adopts a coaxial arrangement of the shift drive system and the power transmission system to increase the compactness of the structure in the axial direction. At the same time, the shift coupling sleeve provided by the present invention is arranged at the central axis of the first outer planetary carrier. The radial and axial dimensions of the shift coupling sleeve are small, making the structure more compact and facilitating the arrangement of other components. The present invention uses a disc brake and arranges the brake caliper in the radial direction of the wheel edge to fully utilize the radial dimension space of the structure.

[0030] 2. The shift transmission system provided by the present invention is a two-speed, three-stage reducer. The fixed-axis gear train reduction mechanism within the shift transmission system offsets the high-speed drive motor, thereby leaving more space for the lower suspension arm. This ensures that the high-speed drive motor does not interfere with the vehicle suspension when the vehicle's suspension reaches its maximum downward travel. The shift drive is electronically controlled, ensuring precise and controllable shifting. The fixed-axis gear train reduction mechanism, combined with the first and second planetary gear train reduction mechanisms, and the shift transmission arrangement provide for more flexible transmission ratio distribution within the transmission system.

[0031] 3. The shift mechanism of the present invention respectively uses two spline hubs to engage with the ring gear bracket and the outer planetary carrier of the first planetary gear train reduction mechanism. The transmission ratio of the first planetary gear train reduction mechanism is controlled by the engagement and disengagement of the coupling sleeve and the spline hub. At the same time, the shift mechanism cooperates with the planetary gear train reduction mechanism to ensure a large transmission ratio difference between high-speed gear and low-speed gear, meeting the vehicle's needs for two different working conditions: low-speed high torque and high-speed low torque, allowing the vehicle to better adapt to complex driving conditions. At the same time, the output torque is increased, so that the motor always operates in a high-efficiency range, improving the vehicle's power economy and extending the driving range.

[0032] 4. The shift drive mechanism of the present invention uses bevel gear meshing and reversing combined with a screw transmission to drive the shift fork to move axially, thereby driving the clutch sleeve to achieve gear shifting. This method fully utilizes the characteristics of the screw transmission, such as stable output power, increased output torque, and self-locking properties, to effectively prevent the vehicle from shifting out of gear during driving. In addition, this drive method uses bevel gear meshing and reversing, fully utilizing the axial and radial dimensions of the transmission structure.

[0033] 5. The shift drive system employed in this invention is either electric or electromagnetic, offering high precision, ease of control, accurate response, and strong reliability, making it more suitable for integration. The shifting process is achieved through the coordinated cooperation of a high-speed drive motor and the shift drive mechanism, simplifying the shifting structure and enabling synchronizer-free shifting.

[0034] 6. The power output of the second planetary gear reduction mechanism in the present invention is ensured by the interference fit between the conical surface of the second outer planetary carrier and the transition flange. This approach effectively utilizes axial space, transmits a large output torque, provides stable output, and avoids the impact caused by meshing clearance in spline connections. Furthermore, to ensure the conical surface fit is concentric, studs and hexagonal flange nuts are used at the center of the second outer planetary carrier and the transition flange to prevent eccentricity of the conical surface fit caused by the gap between the second outer planetary carrier and the transition flange. Furthermore, the two end faces of the transition flange respectively mate with the brake disc and the wheel rim, and are fastened together by wheel bolts and nuts. This structure not only serves as a centering function but also prevents deformation of the brake disc caused by the wheel rim squeezing the brake disc after tightening the wheel bolts and nuts.

[0035] 7. The coupling sleeve provided by the present invention cooperates with the first spline hub and the second spline hub connected to the ring gear bracket to complete the gear shifting process. The matching position of the coupling sleeve and the first spline hub and the second spline hub is close to the central axis and has a small radial size, which avoids the disadvantage of the conventional coupling sleeve having a large radial size and generating a certain torque to reduce the strength, thereby improving the structural strength.

[0036] 8. The device makes full use of the axial and radial dimensions of the structure, has a compact structure, a more flexible overall layout, is light in weight, highly integrated, and has efficient transmission. The setting of the shift mechanism greatly improves the vehicle's ability to climb slopes, cross trenches, and overcome obstacles. It is especially suitable for four-wheel drive off-road vehicles working on rugged roads. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0038] Figure 1 This is a cross-sectional view of the assembly of the electric drive wheel set of the present invention;

[0039] Figure 2 This is a three-dimensional structural diagram of the electric drive wheel set of the present invention;

[0040] Figure 3 This is a diagram showing the gear shifting and transmission relationship of the electric drive wheel set of the present invention;

[0041] Figure 4 This is a structural diagram of the low-speed gear of the electric drive wheel assembly of the present invention;

[0042] Figure 5 This is a high-speed gear structure diagram of the electric drive wheel assembly of the present invention;

[0043] Figure 6 This is an exploded view of the first planetary gear train of the electric drive wheel assembly of the present invention;

[0044] Figure 7 An exploded view of the electric drive wheel set shift mechanism and the shift drive mechanism of the present invention;

[0045] Figure 8 This is an exploded view of the second planetary gear train and wheel-side transmission structure of the electric drive wheel set of the present invention;

[0046] Among them, 1- high-speed drive motor, 2- front end housing, 3- suspension upper swing arm bracket, 4- suspension lower swing arm bracket, 5- middle section housing I, 6- breather plug, 7- high-speed gear shaft, 8- low-speed gear shaft, 9- low-speed gear, 10- first sun gear, 11- first planetary gear, 12- first planetary shaft, 13- first ring gear, 14- first inner planetary carrier, 15- first outer planetary carrier, 16- ring gear bracket, 17- fixed bracket, 18- coupling sleeve, 19- first spline hub, 20- second spline hub, 21- shift fork, 22- bevel gear shift fork shaft, 23- drive device, 24-driving bevel gear shaft, 25-oil seal seat, 26-middle section housing II, 27-second inner planetary carrier, 28-second sun gear, 29-second ring gear, 30-second planetary gear, 31-second planetary shaft, 32-second outer planetary carrier, 33-transition flange, 34-hexagonal flange nut, 35-stud, 36-brake caliper, 37-brake disc, 38-wheel rim, 101-fixed axis gear train reduction mechanism, 102-first planetary gear train reduction mechanism, 103-second planetary gear train reduction mechanism, 201-shift mechanism, 202-shift drive mechanism, 301-brake system. DETAILED DESCRIPTION

[0047] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0048] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0049] Example 1: A two-speed hub-integrated electric drive wheel set

[0050] like Figures 1 to 3As shown, a two-speed hub integrated electric drive wheel set includes a front end housing 2, a middle housing I5, a middle housing II26, a rear end housing 39, a high-speed drive motor 1, a fixed-axis gear train reduction mechanism 101, a first planetary gear train reduction mechanism 102, a second planetary gear train reduction mechanism 103, a shift mechanism 201, a shift drive mechanism 202, a transition flange 33, a suspension upper swing arm support 3, a suspension lower swing arm support 4, a braking system 301 and a rim 38.

[0051] The high-speed drive motor 1, front housing 2, and middle housing I5 are located outside the rim 38. The high-speed drive motor 1 and the front housing 2 are connected by a shared end cap, that is, one end of the front housing 2 serves as the front end cap of the high-speed drive motor to achieve an integrated design of the motor and housing. The front housing 2, middle housing I5, middle housing II 26, and rear housing 39 are connected in sequence, and a toe is provided at the connection position of each adjacent housing to ensure the transmission accuracy requirements of the coaxial arrangement of the transmission mechanism. The output shaft of the high-speed drive motor 1 is connected to the input shaft of the fixed-axis gear train reduction mechanism 101. The output power of the high-speed drive motor 1 is transmitted to the wheel in sequence through the fixed-axis gear train reduction mechanism 101, the first planetary gear train reduction mechanism 102, the second planetary gear train reduction mechanism 103, the transition flange 33, and the rim 38. Among them, power is transmitted between the high-speed drive motor 1 and the second planetary gear reduction mechanism 102 by gear meshing, and power is transmitted between the output shaft of the second planetary gear reduction mechanism 102 and the transition flange 33 by a conical interference fit.

[0052] The fixed axis gear train reduction mechanism 101 includes: a high-speed gear shaft 7, a low-speed gear 9, and a low-speed gear shaft 8. The high-speed gear shaft 7 is the input shaft of the fixed axis gear train reduction mechanism 101 and is spline-connected to the output shaft of the high-speed drive motor 1. The low-speed gear 9 is fixedly arranged on the periphery of one end of the low-speed gear shaft 8. The outer teeth of the high-speed gear shaft 7 and the low-speed gear 9 mesh with each other to transmit power to the low-speed gear shaft 8. The high-speed gear shaft 7 and the low-speed gear 9 are respectively arranged between the front end housing 2 and the middle section housing I5, and are respectively supported by deep groove ball bearings to ensure the transmission accuracy of the fixed axis gear train. Figure 1 and Figure 6As shown, the first planetary gear reduction mechanism 102 is arranged at the other end of the low-speed gear shaft 8, and structurally includes: a first sun gear 10, a first planetary gear 11, a first planetary shaft 12, a first ring gear 13, a first inner planetary carrier 14, a first outer planetary carrier 15 and a ring gear bracket 16. The inner ring of the first sun gear 10 is provided with an internal spline, which is connected to the low-speed gear shaft 8. The outer ring of the first sun gear 10 is meshed with the first planetary gear 11. The first planetary gear 11 is loosely sleeved on the first planetary shaft 12 through a needle bearing and rotates relative to the first planetary shaft 12. The first planetary gear 11 is arranged between the first inner planetary carrier 14 and the first outer planetary carrier 15. The first inner planetary carrier 14 and the first outer planetary carrier 15 are connected to each other. Both are provided with holes that cooperate with the first planetary shaft 12, and the two ends of the first planetary shaft 12 are supported in the holes that cooperate with the first outer planetary carrier 15 and the first inner planetary carrier 14 by interference fit and clearance fit respectively. The first inner planetary carrier 14 and the first outer planetary carrier 15 are respectively supported on the middle section housing Ⅰ5 and the second outer planetary carrier 32 through tapered roller bearings. In addition, in order to reduce the wear between the two ends of the first sun gear 10 and the first planetary gear 11 and the first inner planetary carrier 14 and the first outer planetary carrier 15 during the meshing movement, gaskets with higher hardness after heat treatment are respectively provided between the first sun gear 10, the first planetary gear 11 and the first inner planetary carrier 14 and the first outer planetary carrier 15. The first gear ring 13 is arranged on the periphery of the first planetary gear 11. The inner ring of the first gear ring 13 is respectively provided with meshing teeth that mesh with the first planetary gear 11 and the gear ring bracket 16. The height of the teeth on the first gear ring 13 that engage with the first planetary gear 11 is greater than the height of the teeth that engage with the gear ring bracket 16. The height difference of the teeth on the first gear ring 13 can play a role in shaft shoulder positioning and cooperate with the retaining spring to axially fix the gear ring bracket 16 to the first gear ring 13. The gear ring bracket 16 is respectively provided with teeth that engage with the first gear ring 13 and the first spline hub 19 in the shift mechanism. Figure 6 As shown, the first outer planetary carrier 15 includes a frame body located on the periphery of the first planetary gear 11 and a central axis connected to the frame body. The central axis of the first outer planetary carrier 15 is a solid, and the outside is respectively provided with coupling teeth that cooperate with the second spline hub 20 in the shift mechanism and the second sun gear in the second planetary gear train reduction mechanism. The ring gear bracket 16 is supported on the fixed bracket 17 in the shift mechanism through two angular contact ball bearings. The fixed bracket 17 is provided with a boss as the shaft shoulder of the two angular contact ball bearings, and cooperates with a retaining spring to play an axial limiting role on the first ring gear 13, thereby ensuring the gap between the first outer planetary carrier 15 and the ring gear bracket 16.

[0053] like Figure 1 and Figure 8As shown, the second planetary gear train reduction mechanism 103 includes: a second sun gear 28 , second planetary gears 30 , a second planetary shaft 31 , a second ring gear 29 , a second inner planet carrier 27 , and a second outer planet carrier 32 . The second planetary gear 30 is arranged between the second inner planetary carrier 27 and the second outer planetary carrier 32. The inner ring of the second sun gear 28 is provided with an internal spline, which is connected to the central axis of the first outer planetary carrier 15. The first outer planetary carrier 15 serves as the input shaft of the second planetary gear reduction mechanism. The outer ring of the second sun gear 28 is meshed with the second planetary gear 30. The second planetary gear 30 is loosely sleeved on the second planetary shaft 31 through a needle bearing and rotates relative to the second planetary shaft 31. The second inner planetary carrier 27 and the second outer planetary carrier 32 are both provided with holes that cooperate with the second planetary shaft 31. The two ends of the second planetary shaft 31 are respectively supported in the holes that cooperate with the second outer planetary carrier 32 and the second inner planetary carrier 27 by interference and clearance fit. The second inner planetary carrier 27 and the second outer planetary carrier 32 are respectively supported on the middle section housing II 26 and the rear end housing 39 through tapered roller bearings. Furthermore, to reduce wear between the ends of the second sun gear 28 and the second planet gears 30 and the second inner planet carrier 27 and the second outer planet carrier 32 during meshing, heat-treated, high-hardness washers are installed between the second sun gear 28 and the second planet gears 30 and the second inner planet carrier 27 and the second outer planet carrier 32, respectively. The ends of the first outer planet carrier 15 are supported on the second outer planet carrier 32 via angular contact ball bearings. To adhere to the principles of high transmission efficiency, compact size, light weight, and ease of manufacturing, both sets of planetary gears are NGW-type.

[0054] Specifically, the gear matching parameters of the first gear ring 13 and the gear ring bracket 16 are the same as the gear parameters of the first gear ring 13 . This method can facilitate one-time processing and forming of the first gear ring 13 .

[0055] like Figure 1 and Figure 7As shown, the shifting mechanism 201 is arranged between the first planetary gear train reduction mechanism 102 and the second planetary gear train reduction mechanism 103, and includes: a fixed bracket 17, an engagement sleeve 18, a first spline hub 19 and a second spline hub 20. The shifting mechanism 201 cooperates with the coupling teeth of the ring gear bracket 16 and the coupling teeth of the first outer planetary carrier 15 in the first planetary gear train reduction mechanism 201 to transmit power. The ring gear bracket 16 is supported on the fixed bracket 17 in the shift mechanism through two angular contact ball bearings; the outer surface of the coupling sleeve 18 is I-shaped and is arranged on the periphery of the fixed bracket 17 and the first spline hub 19; the fixed bracket 17 in the shift mechanism 201 is fixedly connected to the middle section housing Ⅰ5, and is provided with a spline connected to the coupling sleeve 18, the first spline hub 19 and the second spline hub 20 are axially fixed to the ring gear bracket 16 and the first outer planetary carrier 15 respectively by means of a retaining spring, the inner ring spline of the first spline hub 19 is connected to the coupling teeth of the ring gear bracket 16, the inner ring spline of the second spline hub 20 is connected to the coupling teeth of the first outer planetary carrier 15, and the outer ring splines of the fixed bracket 17, the first spline hub 19 and the second spline hub 20 are all connected to the coupling teeth of the coupling sleeve 18.

[0056] The transmission method of the two-speed hub integrated electric drive wheel set provided by the present invention is as follows: Figure 4 As shown, when the engaging teeth of the engagement sleeve 18 are simultaneously gear-connected with the outer ring splines of the fixed bracket 17 and the first spline hub 19, the first ring gear 13 remains stationary, and the transmission state of the first planetary gear reduction mechanism 102 is: power is input by the first sun gear 10, and after the first planetary gear 11 is geared with the first sun gear 10 and the first ring gear 13, a larger reduction ratio is achieved, and the power is output by the first outer planetary carrier 15. At this time, the first planetary gear reduction mechanism 102, the fixed-axis gear reduction mechanism 101, and the second planetary gear reduction mechanism 103 form a three-stage reduction mechanism, that is, a low-speed gear transmission, and the low-speed gear ratio is the product of the transmission ratios of the fixed-axis gear train, the first planetary gear train, and the second planetary gear train; as shown Figure 5 As shown, when the engaging teeth of the coupling sleeve 18 are simultaneously matched with the outer ring splines of the first spline hub 19 and the second spline hub 20, the first ring gear 13 and the first outer planetary carrier 15 will always maintain a synchronous speed. After the power is input by the first sun gear 10, the power will be output from the first outer planetary carrier 15 with a transmission ratio of 1:1. At this time, since the transmission ratio of the first planetary gear train reduction mechanism 102 is 1:1, the three-stage reduction mechanism is reduced to a two-stage reduction mechanism, that is, a high-speed gear transmission. The high-speed gear ratio is the product of the transmission ratios of the fixed-axis gear train and the second planetary gear train.

[0057] Specifically, at the spline matching position between the engagement sleeve 18 and the fixed bracket 17 and the second spline hub 20 in the shift mechanism 201, large chamfers are provided at both ends of the spline, thereby ensuring that the engagement sleeve 18 can slide smoothly to the fixed bracket 17 or the second spline hub 20.

[0058] The shift drive mechanism 202 includes: a shift fork 21, a bevel gear shift fork shaft 22, a driving bevel gear shaft 24, a drive device 23, and an oil seal seat 25. The bevel gear shift fork shaft 22 and the driving bevel gear shaft 24 are respectively supported in the middle section housing II 26 through angular contact ball bearings. The shift fork 21 is stuck in the middle of the I-shaped outer surface of the engagement sleeve 18. The bevel gear shift fork shaft 22 and the driving bevel gear shaft 24 are engaged and driven by a bevel gear structure. The bevel gear shift fork shaft 22 passes through the shift fork 21. The shift fork 21 and the bevel gear shift fork shaft 22 are both provided with rectangular or trapezoidal transmission threads at the contact position to realize transmission. The drive device 23 is connected to the driving bevel gear shaft 24. Gear shaft 24 provides rotational power for the driving bevel gear shaft 24. The driving bevel gear shaft 24 is threaded through and fixed to the oil seal seat 25 of the middle housing II 26. The output power of the drive unit 23, after the bevel gears mesh and reverse direction between the driving bevel gear shaft 24 and the bevel gear shift fork shaft 22, is transmitted to the threaded mating position between the bevel gear shift fork shaft 22 and the shift fork 21. This power drives the bevel gear shift fork shaft 22 to rotate under the action of the angular contact ball bearings. At this mating position, the interaction between the rectangular or trapezoidal threads drives the shift fork 21 relative to the bevel gear shift fork shaft 22, thereby driving the reciprocating translation of the shift mechanism's engagement sleeve 18. The drive unit 23 in the shift drive mechanism 202 is driven electrically or electromagnetically. The driving bevel gear shaft 24 has an external spline on the other end of the bevel gear that mates with the internal spline of the drive unit 23 to achieve power transmission.

[0059] The present invention also includes a vehicle controller (VCU), which is individually connected to the high-speed drive motors of each wheel. The VCU sends different torque signals to the four motors. Normally, the electric wheel assembly operates in high gear, switching to low gear only when insufficient torque is encountered.

[0060] In addition, in order to avoid the collision impact of the engaging teeth caused by the high speed difference during the gear shifting process, the driving device 23 is coordinated with the high-speed drive motor 1, that is, when the driving device 23 drives the engaging sleeve 18 to slide to the first spline hub 19, at this time, the internal splines of the engaging sleeve 18 are only engaged with the external splines of the first spline hub, and are disengaged from the external splines of the fixed bracket 17 and the second spline hub 20, that is, in the neutral position, and the width of the engaging sleeve 18 should be slightly smaller than the external spline engagement of the first spline hub 19. The width of the teeth; after entering the neutral position, when entering the high-speed gear mode, the driving device 23 drives the coupling sleeve 18 to slide to the right from the neutral position. At this time, the internal splines of the coupling sleeve 18 are simultaneously engaged with the external splines of the first spline hub 19 and the second spline hub 20 for transmission; when entering the low-speed gear mode, the driving device 23 drives the coupling sleeve 18 to slide to the left from the neutral position. At this time, the internal splines of the coupling sleeve 18 are simultaneously engaged with the external splines of the first spline hub 19 and the fixed bracket 17 for transmission. During the shifting process, only the second splined hub 20 rotates with the first outer planetary carrier 15 while the vehicle is moving, and the first ring gear 13 enters a free mode state. Therefore, when shifting to low gear mode, significant shift shock is avoided. When shifting to high gear mode, the first ring gear 13, connected to the first splined hub 19, is in a free mode state, allowing vehicle speed to be controlled. The simultaneous engagement of the internal splines of the coupling sleeve 18 with the external splines of the first splined hub 19 and the second splined hub 20 also avoids significant shift shock. If higher shift shock requirements are required, a shift synchronizer can be provided between the first splined hub 19, the fixed bracket 17, and the second splined hub 20 to further reduce shift shock.

[0061] Preferably, the gear shift drive device 23 is a servo motor or a stepping motor.

[0062] Specifically, oil seals are installed between the front housing 2 and the high-speed gear shaft 7, between the middle housing II 26 and the driving bevel gear shaft 24, and between the rear housing 39 and the second outer planetary carrier 32. To maintain stable air pressure within the wheelset, a vent plug 6 is installed in the middle housing I 5.

[0063] The brake system 301 includes a brake caliper 36 and a brake disc 37. The brake caliper 36 is fixedly connected to the rear end housing 39. Bolt holes are provided on the transition flange 33, the brake disc 37, and the wheel rim 38, and they are fixed together using bolts and nuts. To ensure the coaxiality requirements between the wheel and the drivetrain, the transition flange 33 is provided with a toe that mates with the wheel rim 38. The conical interference fit between the transition flange 33 and the second outer planetary carrier 32 is achieved by pre-tightening studs 35 and hexagonal flange nuts 34.

[0064] Specifically, considering the cost and difficulty of processing and manufacturing, the gears and splines in the electric drive wheel set can be processed by hobbing and shaping, and the splines of some structures are provided with tool relief grooves for hobbing.

[0065] Example 2, a vehicle comprising an electric wheel set

[0066] Including the two-speed hub integrated electric drive wheel set provided in Example 1, such as Figure 1 As shown, the upper suspension arm support 3 is fixed to the upper end of the middle section shell Ⅰ5, and the lower suspension arm support 4 is fixed to the lower end of the middle section shell Ⅰ5, and is connected to the vehicle frame through the upper suspension arm support 3 and the lower suspension arm support 4.

[0067] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A two-speed hub integrated electric drive wheel set, characterized in that: It includes a front housing, a middle housing I, a middle housing II, a rear housing, a drive motor, a fixed-axis gear train reduction mechanism, a first planetary gear train reduction mechanism, a second planetary gear train reduction mechanism, a shift mechanism, a transition flange and a rim; The drive motor, front housing, and middle housing I are located outside the rim, and the drive motor and front housing are an integrated structure; one end of the middle housing II is connected to the middle housing I, and the other end passes through the rim and is connected to the rear housing; the output power of the drive motor is sequentially transmitted to the wheel through the fixed-axis gear train reduction mechanism, the first planetary gear train reduction mechanism, the second planetary gear train reduction mechanism, the transition flange, and the rim; The shift mechanism is arranged between the first planetary gear train reduction mechanism and the second planetary gear train reduction mechanism; The first planetary gear train reduction mechanism includes a first sun gear, a first planet gear, a first planet shaft, a first ring gear, a first inner planet carrier, a first outer planet carrier and a ring gear support; The shift mechanism includes a fixed bracket, an engagement sleeve, a first spline hub, and a second spline hub. The shift mechanism cooperates with the coupling teeth of the ring gear bracket and the coupling teeth of the first outer planetary carrier in the first planetary gear train reduction mechanism to transmit power. The ring gear bracket of the first planetary gear train reduction mechanism is supported on the fixed bracket in the shift mechanism by two angular contact ball bearings. The fixed bracket is provided with a boss as a shoulder of the two angular contact ball bearings. The engagement sleeve is provided on the periphery of the fixed bracket and the first spline hub. The fixed bracket in the shift mechanism is fixedly connected to the middle section housing I and is provided with a spline that is matched with the teeth of the engagement sleeve. The first spline hub and the second spline hub are axially fixed to the ring gear bracket and the first outer planetary carrier respectively by a retaining spring. The inner ring spline of the first spline hub is matched with the coupling teeth of the ring gear bracket, and the inner ring spline of the second spline hub is matched with the coupling teeth of the first outer planetary carrier. The outer ring splines of the fixed bracket, the first spline hub, and the second spline hub are all matched with the coupling teeth of the engagement sleeve. The outer surface of the coupling sleeve is I-shaped; It also includes a shift drive mechanism, which includes: a shift fork, a bevel gear shift fork shaft, a driving bevel gear shaft, an electric drive device, and an oil seal seat. The bevel gear shift fork shaft and the driving bevel gear shaft are respectively arranged in the middle section housing II, and the shift fork is stuck in the middle of the I-shaped outer surface of the engagement sleeve. The bevel gear shift fork shaft and the driving bevel gear shaft are engaged and transmitted through a bevel gear structure. The bevel gear shift fork shaft passes through the shift fork. The shift fork and the bevel gear shift fork shaft are both provided with transmission threads at the contact position to realize transmission. The electric drive device is connected to the driving bevel gear shaft, and the driving bevel gear shaft is fixed to the oil seal seat of the middle section housing II through a threaded structure.

2. The two-speed hub-integrated electric drive wheel set according to claim 1, characterized in that: The fixed-axis gear train reduction mechanism includes a high-speed gear shaft, a low-speed gear and a low-speed gear shaft. The high-speed gear shaft is fixedly connected to the output shaft of the drive motor. The low-speed gear is arranged on the periphery of one end of the low-speed gear shaft. The outer teeth of the high-speed gear shaft and the low-speed gear are engaged with each other to transmit power to the low-speed gear shaft. The high-speed gear shaft and the low-speed gear are respectively arranged at the connection position of the front end housing and the middle section housing I, and are supported by deep groove ball bearings.

3. The two-speed hub-integrated electric drive wheel set according to claim 2, characterized in that: In the first planetary gear reduction mechanism, the inner ring of the first sun gear is fixedly connected to the low-speed gear shaft, and the outer ring is meshed with the first planetary gear. The first planetary gear is loosely sleeved on the first planetary shaft through a needle bearing and rotates relative to the first planetary shaft. The first inner planetary carrier and the first outer planetary carrier are both provided with holes that cooperate with the first planetary shaft. The two ends of the first planetary shaft are supported in the holes that cooperate with the first outer planetary carrier and the first inner planetary carrier by interference fit and clearance fit, respectively. The first inner planetary carrier and the first outer planetary carrier are respectively supported on the middle section housing I and the second planetary gear reduction mechanism through tapered roller bearings; the first ring gear is meshed with the first planetary gear and the ring gear bracket through meshing teeth, respectively. The height of the combined teeth on the first ring gear with the first planetary gear is greater than the height of the combined teeth with the ring gear bracket, so that the ring gear bracket is axially fixed to the first ring gear.

4. The two-speed hub-integrated electric drive wheel set according to claim 3, characterized in that: The second planetary gear reduction mechanism includes: a second sun gear, a second planetary gear, a second planetary shaft, a second ring gear, a second inner planetary carrier, and a second outer planetary carrier; the inner ring of the second sun gear is provided with an internal spline, which is connected to the first outer planetary carrier, and the outer ring is meshed with the second planetary gear. The second planetary gear is loosely sleeved on the second planetary shaft through a needle roller bearing and rotates relative to the second planetary shaft. The second inner planetary carrier and the second outer planetary carrier are both provided with holes that cooperate with the second planetary shaft. The two ends of the second planetary shaft are supported in the holes that cooperate with the second outer planetary carrier and the second inner planetary carrier by interference fit and clearance fit respectively. The second inner planetary carrier and the second outer planetary carrier are respectively supported on the middle section housing II and the rear end housing through tapered roller bearings.

5. The two-speed hub-integrated electric drive wheel set according to claim 4, characterized in that: The width of the engagement sleeve is smaller than the width of the outer ring spline engaging teeth in the first spline hub.

6. The two-speed hub-integrated electric drive wheel set according to claim 5, characterized in that: It also includes a vehicle controller, which is connected to the drive motor of each wheel respectively, and sends different torque signals to the four drive motors.

7. The two-speed hub-integrated electric drive wheel set according to claim 6, characterized in that: When the engaging teeth of the engagement sleeve are simultaneously gear-connected with the outer ring splines of the fixed bracket and the first spline hub, the first ring gear remains stationary, and the transmission state of the first planetary gear train reduction mechanism is: power is input by the first sun gear, and after the first planetary gear, the first sun gear and the first ring gear are geared and transmitted, the power is output by the first outer planetary carrier. At this time, the first planetary gear train reduction mechanism, the fixed-axis gear train reduction mechanism and the second planetary gear train reduction mechanism form a three-stage reduction mechanism, and the low-speed gear ratio is the product of the transmission ratios of the fixed-axis gear train, the first planetary gear train and the second planetary gear train; when the engaging teeth of the engagement sleeve are simultaneously gear-connected with the outer ring splines of the first spline hub and the second spline hub, the first ring gear and the first outer planetary carrier will always maintain a synchronous speed. After the power is input by the first sun gear, it will be output by the first outer planetary carrier with a 1:1 transmission ratio.

8. A vehicle, characterized in that: A vehicle comprising a two-speed hub-integrated electric drive wheel assembly according to any one of claims 1 to 7, wherein the two-speed hub-integrated electric drive wheel assembly is connected to the vehicle frame via a suspension upper swing arm support fixed to the upper end of the middle section shell I and a suspension lower swing arm support fixed to the lower end of the middle section shell I.

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