Drive axle and electric vehicle with integrated braking function

Abstract

The present invention discloses a drive axle and an electric vehicle with integrated braking function, comprising a drive axle body, wheels connected to both ends of the drive axle body, and two wheel-side motor assemblies arranged in the middle of the drive axle body and correspondingly connected to the two wheels, the two wheel-side motor assemblies are integrated into one body, and are used to independently control the driving or braking of the corresponding wheels; a single wheel-side motor assembly comprises a motor body and an electronic mechanical brake component, the power output end of the motor body is connected to the wheel transmission through a reducer, and the electronic mechanical brake component acts on the motor shaft of the motor body, and is used to brake the motor shaft of the motor body. It has a compact structure, eliminates the existing brake caliper, integrates the braking function and the brake together, realizes the high integration of the vehicle chassis and expands the higher level of chassis electronic control.

Description

Technical Field

[0001] The invention relates to the technical field of automobile drive axles, and in particular to a drive axle with integrated braking function and an electric vehicle. Background Art

[0002] Research background and advantages of electronic mechanical brake system In today's society, economy and science and technology, people are pursuing the power and comfort of automobiles, and at the same time, they are paying more and more attention to automobile safety. Among them, the braking performance of automobiles is particularly important, because the braking performance of automobiles is directly related to the safety of life and property, and good braking performance is the basic guarantee for safe driving of automobiles. The hydraulic brake system widely used in modern vehicles is mainly composed of brake pedal, brake master cylinder, vacuum booster, hydraulic pipeline, brake wheel cylinder, brake and other parts. When the vehicle needs to brake, the driver steps on the brake pedal, and with the help of a series of mechanical structures and vacuum boosters, the oil in the brake master cylinder flows into each wheel cylinder through the brake pipeline at a certain pressure, and finally drives the disc or drum brake to complete the braking action, thereby achieving wheel braking. After a long period of development, hydraulic braking has become a very mature technology, and modern cars basically all use hydraulic brake systems. However, the system also has the following problems: there are many mechanical parts and hydraulic pipelines, and the vacuum booster is large in size. Especially after integrating electronic control functions such as ABS, TCS, and ESP, the system is more complicated and difficult to arrange and assemble; the hydraulic oil needs to be replaced regularly, and there is a risk of leakage during use, which pollutes the environment; for new energy vehicles with brake energy recovery systems and lack of booster vacuum sources, the use of hydraulic brake systems is limited and matching is difficult. With the development of science and technology, electronic mechanical brake systems with more compact structures, greater output braking force, and more reliable operation have emerged. Because it can solve the above-mentioned problems that have plagued hydraulic brake systems for many years. Internationally, electronic mechanical brake systems have become one of the trends in brake technology research. As a type of electronic mechanical brake system Brake-By-Wire, a new braking concept is proposed.

[0003] Comparison between electronic mechanical braking and traditional hydraulic braking system The electronic mechanical braking system uses electrical energy as its energy source. The motor drives the brake pad to press the brake disc to achieve the braking function. The energy is transmitted by the wire and the signal is transmitted by the data line. Its simple structure and efficient performance greatly improve the braking safety of the car. Compared with the traditional hydraulic braking system, the electronic mechanical braking system has the following main advantages:

[0004] 1. Fewer mechanical connections and no hydraulic brake lines can effectively reduce the weight of the vehicle; the structure is simple, the volume is small, and it is easy to arrange;

[0005] 2. Mechanical and electrical connections are adopted, signal transmission is rapid, braking response is fast and responsive;

[0006] 3. High transmission efficiency and energy saving;

[0007] 4. The electronic intelligent control function is powerful. It can realize complex electronic control functions such as ABS, TCS, ESP, ACC, etc. by modifying the software program in the ECU and configuring related parameters. It is also easy to match with new energy vehicles with brake energy recovery systems;

[0008] 5. The whole system adopts modular structure, which is easy to assemble and maintain;

[0009] 6. The electronic pedal eliminates the mechanical and hydraulic connection between the brake pedal and the brake actuator. On the one hand, the brake pedal will not rebound and vibrate when performing actions such as ABS, which improves braking comfort; on the other hand, when the vehicle collides, the impact force will not be transmitted to the cab through the braking system, which improves the passive safety of the car.

[0010] 7. There are no hydraulic brake lines and brake fluid, so there is no problem of replacing hydraulic oil or hydraulic oil leakage, which is beneficial to environmental protection. The electronic mechanical brake system has no non-recyclable parts and has almost no pollution to the environment;

[0011] 8. More communication interfaces can be expanded, which improves the integration of the braking system and the vehicle's intelligent networking. The vehicle's four-wheel brakes can be controlled independently, thus achieving a higher level of unmanned driving.

[0012] Analysis of the development scenario of electronic mechanical braking technology: This invention aims to provide a component solution and some useful experience for the development of electronic mechanical braking systems and the realization of various active safety functions of automobiles in the future. In addition, after actual vehicle application, the motor must adapt to various harsh and complex working environments. Therefore, in the future, it is necessary to propose the performance indicators of the drive motor specifically for the use requirements of the electronic mechanical braking system for the drive motor, and design and manufacture electronic mechanical braking drive motors with excellent performance and high integration based on this. Of course, this depends on in-depth research on the basic theory of motors and breakthroughs in material science. In order for the electronic mechanical braking system to truly realize the braking function and then carry out research on complex electronic control functions such as ABS, TCS, and ESP, a set of electronic mechanical braking control systems must be developed first. This requires a lot of in-depth and detailed research in the selection of control chips, the design of control circuits, and the research of control strategies. Research on the reliability of electronic mechanical braking systems. In order to ensure braking safety, the automobile braking system requires a certain degree of redundancy. Since the electronic mechanical braking system cancels the mechanical hydraulic connection between the brake pedal and the brake, it cannot use the redundant structure of the traditional braking system. This requires reconsidering the design of the redundancy of the electronic mechanical braking system from the perspective of structure and control. In addition, in order to ensure safety and facilitate maintenance, the electronic mechanical brake system should have a complete fault diagnosis system, and display the fault code through the indication signal or record it, so as to facilitate subsequent detection and maintenance. Design and research of electronic pedal and pedal force simulator. In order to allow the driver to get the same feeling as before through the brake pedal when braking, it is necessary to develop a set of brake pedals and pedal force simulation mechanism assemblies that can well simulate the pedal feeling of the traditional hydraulic brake system. This requires research and verification from both subjective and objective aspects. Communication between electronic mechanical brake system and vehicle control. The control mode of modern automobiles is gradually changing from the past decentralized and independent control mode to a comprehensive and interrelated control mode. As an important component of the electronic mechanical brake system, its communication and coordination with the vehicle controller and the engine, transmission and other controls will become an important research topic. The electronic mechanical brake system is a new braking concept. Although it has not been industrialized at this stage due to the constraints of motor performance, vehicle power system load, cost, reliability and other aspects, it has become one of the future development directions of vehicle brake systems with its advantages in response speed, energy saving and environmental protection. As long as we seize the opportunity, meet the challenge, carry out continuous research in the development of electronic mechanical brake systems, and gradually deepen and refine the work we do, we believe that in the future, as the ice that restricts the development of electronic mechanical brake systems is broken one by one, the conditions for the industrialization of electronic mechanical brakes will gradually mature. We believe that electronic mechanical brake technology has a bright future and will surely receive more and more attention and favor.

[0013] Therefore, it is necessary to develop an electromechanical brake system and a vehicle with integrated driving and braking for a vehicle. Summary of the invention

[0014] The purpose of the present invention is to provide a drive axle and electric vehicle with integrated braking function, which have a compact structure, eliminate the brake calipers, brake discs, hydraulic pipelines and vacuum booster pumps of traditional vehicles, and redundantly integrate the braking and driving hardware and software to achieve high integration of the vehicle chassis and expand higher-level chassis electronic control.

[0015] The drive axle with integrated braking function described in the present invention includes a drive axle body, wheels connected to both ends of the drive axle body, and two wheel-side motor assemblies arranged in the middle of the drive axle body and correspondingly connected to the two wheels. The two wheel-side motor assemblies are integrated into one body for independently controlling the driving or braking of the corresponding wheels. A single wheel-side motor assembly includes a motor body and an electronic mechanical brake component. The power output end of the motor body is connected to the wheel transmission through a reducer, and the electronic mechanical brake component acts on the motor shaft of the motor body for braking the motor shaft of the motor body.

[0016] Furthermore, the reducer is a two-stage planetary gear reducer, the power output end of the motor body is transmission connected to the sun gear of the first-stage planetary gear reducer, the planetary carrier of the first-stage planetary gear reducer is transmission connected to the sun gear of the second-stage planetary gear reducer, the planetary carrier of the second-stage planetary gear reducer is transmission connected to the inner ring of the hub bearing, and the flange of the outer ring of the hub bearing is cooperatively connected to the rim of the wheel.

[0017] Furthermore, the wheel hub bearing is a deep groove ball cylindrical roller wheel hub bearing.

[0018] Furthermore, the electronic mechanical brake component includes a translational friction plate, a rotating friction plate, a drive assembly and a brake shaft, the brake shaft is drivingly connected to the motor shaft of the motor body, the rotating friction plate is fixedly connected to the brake shaft and the rotating friction plate rotates with the brake shaft, the translational friction plate is slidingly connected to the shell of the motor body and the translational friction plate can approach or move away from the rotating friction plate under the action of the drive assembly.

[0019] Furthermore, the driving component includes an electromagnet and a magnet slider, the electromagnet is fixed on the inner side of the shell of the motor body, the magnet slider is arranged within the action range of the electromagnet, and the magnet slider is fixedly connected to the translational friction plate. By adjusting the current size and direction of the electromagnet, the magnet slider is translated along the axial direction of the brake shaft, thereby driving the translational friction plate to approach or move away from the rotating friction plate and adjusting the coupling friction force between the translational friction plate and the rotating friction plate.

[0020] Furthermore, the driving assembly also includes a return spring, one end of which is fixedly connected to the housing of the motor body, and the other end of which is fixedly connected to the magnet slider.

[0021] Furthermore, coils are embedded in the translational friction plate and the rotational friction plate. When the motor body or the translational friction plate or the rotational friction plate is damaged, the electromagnet acts as a safety backup and cooperates with the coil to generate a braking torque. The magnitude and direction of the torque can be coordinated and controlled by controlling the magnitude and direction of the current flowing through the coil.

[0022] Furthermore, the brake shaft is drivingly connected to the motor shaft via a coupling.

[0023] Furthermore, it also includes an inner seat ring and an outer seat ring, the inner seat ring is spline-connected to the brake shaft, and the rotating friction plate is fixed on the inner seat ring; the outer seat ring is spline-connected to the inner wall of the motor housing of the motor body and the outer seat ring can move along the axial direction of the brake shaft, and the translational friction plate is fixed on the outer seat ring.

[0024] Furthermore, the motor body is a brushless DC motor, which receives an action signal from a main controller, controls the motor shaft output, and generates a desired target rotation speed.

[0025] An electric vehicle comprises the drive axle with integrated braking function described in the present invention.

[0026] Compared with the prior art, the present invention has the following beneficial effects.

[0027] 1. The present invention integrates two wheel-side motor assemblies corresponding to the two wheels into one body. Compared with the split arrangement, the integrated arrangement structure is more compact. A single wheel-side motor assembly includes a motor body and an electronic mechanical brake component. The power output end of the motor body is connected to the wheel transmission through a reducer. The electronic mechanical brake component is directly applied to the motor shaft of the motor body to brake the motor shaft of the motor body, eliminating the traditional brake caliper, integrating the brake with the motor body into one, which is highly redundant and makes it easier to achieve a higher level of unmanned driving. In addition, the electronic mechanical brake component uses electrical energy as an energy source, and uses wires to replace the complex pipelines in the traditional brake system to achieve redundant control of wheel brakes and improve vehicle safety performance and response speed. By integrating the drive and brake together, the structure is very compact, achieving a high degree of integration of the entire vehicle chassis and expanding a higher level of chassis electronic control.

[0028] 2. The reducer of the present invention is a two-stage planetary gear reducer. After the power output end of the motor body is decelerated and torque increased by the two-stage planetary gear reducer, the wheels at both ends of the vehicle drive axle body are driven to rotate. The two-stage planetary gear reducer has the advantages of a large transmission ratio range, strong load-bearing capacity, small size, light weight, smooth transmission, high efficiency, reliable operation, and long service life. And under the premise of the same transmission ratio, the volume of the two-stage planetary gear reducer is much smaller than that of the ordinary cylindrical gear reducer. The input shaft and output shaft of the two-stage planetary gear reducer are coaxial, the movement is smooth, and the ability to resist impact and vibration is strong.

[0029] 3. The planet carrier of the second stage planetary gear reducer of the two-stage planetary gear reducer of the present invention is drivingly connected to the inner ring of the hub bearing, thereby generating a driving torque under the drive of the motor body. The flange of the outer ring of the hub bearing is cooperatively connected to the rim of the wheel, and the rim serves as a mounting component for the wheel of the whole vehicle, driving the wheel to rotate or brake during the movement of the vehicle.

[0030] 4. The wheel hub bearing of the present invention is a deep groove ball cylindrical roller wheel hub bearing, in which appropriate rollers are placed between the outer ring and the inner ring as the intermediate transmission body, and the sliding friction is replaced by rolling friction by means of the roller return channel. The deep groove ball cylindrical roller wheel hub bearing has the advantages of high transmission efficiency, stable movement, high precision, high durability and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic structural diagram of a drive axle with integrated braking function according to the present invention;

[0032] Figure 2 It is a schematic diagram of the connection between the wheel-side motor assembly and the reducer of the present invention;

[0033] Figure 3 is a schematic structural diagram of the wheel-side motor assembly of the present invention;

[0034] Figure 4 It is a front view of the drive axle with integrated brake function of the wheel rim;

[0035] Figure 5 is a front view of a drive axle with integrated brake function without wheel rim;

[0036] Figure 6 It is a schematic diagram of the structure of a driving half shaft with integrated braking function of a wheel rim;

[0037] Figure 7 is a schematic diagram of the structure of a drive half shaft without an integrated braking function of a wheel hub bearing outer ring;

[0038] Figure 8 is a schematic diagram of the structure of a drive half shaft with integrated braking function without a wheel hub bearing outer ring and a sealing ring;

[0039] Fig. 9 It is a structural schematic diagram of a single-stage planetary gear reducer;

[0040] Fig.10 It is a schematic diagram of the principle of a single-stage planetary gear reducer.

[0041] In the figure, 1 is the wheel, 2 is the wheel side motor assembly, 21 is the motor body, 211 is the motor shaft, 22 is the electronic mechanical brake, 221 is the translation friction plate, 222 is the rotation friction plate, 223 is the brake shaft, 224 is the electromagnet, 225 is the magnet slider, 226 is the return spring, 227 is the inner race, 228 is the outer race; 3 is the first stage planetary gear reducer, 4 is the second stage planetary gear reducer, 5 is the coupling, 6 is the wheel hub bearing, 61 is the flange, 7 is the sealing ring, 8 is the wheel rim. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0043] See also Figures 1 to 8 The drive axle with integrated braking function shown in the figure includes a drive axle body, wheels 1 connected to both ends of the drive axle body, and two wheel-side motor assemblies 2 arranged in the middle of the drive axle body and correspondingly connected to the two wheels 1. The two wheel-side motor assemblies 2 are integrated into one body for independently controlling the driving or braking of the corresponding wheels 1. Compared with the split arrangement, the integrated arrangement structure is more compact.

[0044] A single wheel-side motor assembly 2 includes a motor body 21 and an electronic mechanical brake component 22. The power output end of the motor body 21, i.e., the motor shaft 211, is connected to the wheel 1 through a reducer. The electronic mechanical brake component 22 acts on the motor shaft 211 of the motor body 21 to brake the motor shaft 211 of the motor body 21. The traditional brake caliper is eliminated, and the brake is integrated with the motor body, which is highly redundant, making it easier to achieve a higher level of unmanned driving. In addition, the electronic mechanical brake component uses electrical energy as an energy source, and uses wires to replace the complex pipelines in the traditional brake system to achieve redundant control of wheel brakes and improve vehicle safety performance and response speed. By integrating the drive and brake together, the structure is very compact, achieving a high degree of integration of the entire vehicle chassis and expanding a higher level of chassis electronic control.

[0045] The reducer is a two-stage planetary gear reducer, the power output end of the motor body 21 is connected to the sun gear of the first-stage planetary gear reducer 3, the planet carrier of the first-stage planetary gear reducer 3 is connected to the sun gear of the second-stage planetary gear reducer 4, the planet carrier of the second-stage planetary gear reducer 4 is connected to the inner ring of the hub bearing 6, and the flange 61 of the outer ring of the hub bearing 6 is connected to the rim of the wheel 1.

[0046] The motor shaft 211 of the motor body 21 drives the sun gear of the first-stage planetary gear reducer 3. The inner gear ring of the first-stage planetary gear reducer 3 is fixed inside the housing of the drive axle body. The output of the planetary carrier of the first-stage planetary gear reducer 3 is used as the power input of the second-stage planetary gear reducer 4. The inner gear ring of the second-stage planetary gear reducer 4 is also fixed inside the housing of the drive axle body, and the planetary carrier of the second-stage planetary gear reducer 4 is used as the output. The output of the motor body 21 drives the wheels 1 at both ends of the vehicle drive axle body to rotate after the two-stage planetary gear reducer is decelerated and torque-increased. The planetary gear reducer can be said to be a special gear transmission mechanism with a variety of structural forms. The transmission ratio is generally large. Under the premise of the same transmission ratio, the volume is much smaller than that of the ordinary cylindrical gear reducer; and its input shaft and output shaft have the characteristics of being coaxial, stable movement, and strong ability to resist impact and vibration. The two-stage planetary gear reducer has the advantages of a large transmission ratio range, strong load-bearing capacity, small volume, light weight, stable transmission, high efficiency, reliable operation, and long service life.

[0047] See also Fig. 9 and Fig.10 The single-stage planetary gear reducer shown in FIG. 1 includes a sun gear a, a planet gear g, a planet carrier H and an inner gear ring b. Assume that the sun gear a is the active part and rotates around a fixed geometric axis O. d The planetary gear g is mounted on the planetary carrier H, which rotates around the fixed axis O H The inner gear ring b is fixed, and when the sun gear a rotates, the planetary gear g rotates around its own axis O. g In addition to its rotation, its axis O g Also with the planet carrier H around the fixed axis O H It revolves around the sun and is finally output by the planet carrier H.

[0048] The wheel hub bearing 6 is a deep groove ball cylindrical roller wheel hub bearing, which places appropriate rollers between the outer ring and the inner ring as an intermediate transmission body, and uses the roller return channel to replace the sliding friction with rolling friction. The deep groove ball cylindrical roller wheel hub bearing has the following advantages.

[0049] 1) High transmission efficiency: The transmission efficiency is as high as 90~98%, which is 2~4 times that of traditional bearings, so the drag torque of the whole vehicle is small.

[0050] 2) Smooth movement: Rolling friction replaces sliding friction, with low friction resistance, high sensitivity, and no vibration during startup, so micro-feed can be precisely controlled.

[0051] 3) High precision: can achieve higher positioning accuracy and repeatability.

[0052] 4) High durability: The rolling contact parts are hardened and precision ground, with HRC hardness reaching 58-63. The circulation system process is pure rolling, with relatively little wear, so it has a long service life and precision retention.

[0053] 5) High reliability. Compared with other mechanical transmissions, the failure rate is very low and the maintenance is relatively simple. Only general lubrication and dust prevention are required. In special occasions, it can work without lubrication.

[0054] See also Figure 3 The electronic mechanical brake component 22 includes a translational friction plate 221, a rotating friction plate 222, a driving assembly and a brake shaft 223. The brake shaft 223 is transmission-connected to the motor shaft 211 of the motor body 21. The rotating friction plate 222 is fixedly connected to the brake shaft 223 and the rotating friction plate 222 rotates with the brake shaft 223. The translational friction plate 221 is slidingly connected to the shell of the motor body 21 and the translational friction plate 221 can approach or move away from the rotating friction plate 222 under the action of the driving assembly.

[0055] The driving assembly includes an electromagnet 224 and a magnet slider 225. The electromagnet 224 is fixed to the inner side of the shell of the motor body 21. The magnet slider 225 is arranged within the action range of the electromagnet 224, and the magnet slider 225 is fixedly connected to the translation friction plate 221. By adjusting the current size and direction of the electromagnet 224, the magnet slider 225 is translated along the axial direction of the brake shaft 223, thereby driving the translation friction plate 221 to approach or move away from the rotating friction plate 222 and adjusting the coupling friction force between the translation friction plate 221 and the rotating friction plate 222.

[0056] The driving assembly further includes a return spring 226, one end of which is fixedly connected to the housing of the motor body 21, and the other end of which is fixedly connected to the magnet slider 225. When the translation friction plate 221 approaches the rotation friction plate 222, the return spring 226 is in a stretched state to store energy for subsequent resetting. When the translation friction plate 221 and the rotation friction plate 222 need to be decoupled, the return spring 226 can assist the movement of the magnet slider 225, so that the translation friction plate can quickly separate from the rotation friction plate, thereby improving the response speed.

[0057] The translational friction plate 221 and the rotational friction plate 222 are embedded with coils. When the motor body 21 is damaged or the translational friction plate 221 and the rotational friction plate 222 are damaged, the electromagnet 224 acts as a safety backup and cooperates with the coil to generate a braking torque. The magnitude and direction of the torque can be coordinated and controlled by controlling the magnitude and direction of the current flowing through the coil.

[0058] In order to make the transmission between the brake shaft 223 and the motor shaft 211 smoother, the brake shaft 223 is connected to the motor shaft 211 through a coupling 5.

[0059] In order to improve the assembly and working stability of the translational friction plate 221 and the rotational friction plate 222, the drive assembly also includes an inner seat ring 227 and an outer seat ring 228. The inner seat ring 227 is splined to the brake shaft 223, and the rotational friction plate 222 is fixed on the inner seat ring 227; the outer seat ring 228 is splined to the inner wall of the motor housing of the motor body 21 and the outer seat ring 228 can move along the axial direction of the brake shaft 223, and the translational friction plate 221 is fixed on the outer seat ring 228.

[0060] The motor body 21 is a brushless DC motor, which receives the action signal from the main controller, controls the output of the motor shaft 211, and generates the desired target speed. The brushless DC motor uses electronic commutation to replace the brushes and commutator, does not generate sparks and wear, and thus has high reliability and long service life. In terms of structure, the permanent magnet is installed on the rotor, so that the motor rotor does not generate heat, thereby reducing motor losses and improving efficiency. The stator can dissipate heat through the casing, and the heat dissipation conditions are improved. In addition, the brushless DC motor is much smaller in weight and size than the brushed DC motor, which is reduced by about 70%; and the moment of inertia can be reduced by about 40-50%. In addition, the brushless DC motor also has a linear torque-speed characteristic similar to that of an ordinary DC motor. Brushless DC motors can be divided into many types according to the different permanent magnet materials used. Among them, the rare earth permanent magnet brushless DC motor is a new technology and new product that has developed rapidly internationally in recent years. It has the advantages of large starting torque, strong overload capacity, convenient speed regulation, stable operation, low noise, and reliable operation. It is an ideal energy-saving, noise-reducing, and environmentally friendly product.

[0061] The wheel-side motor assembly 2 is connected to the motor controller, which includes two parts: a motor controller and an electromagnetic actuator controller. The motor control program in the motor controller receives the target braking force signal from the central control unit, and combines the feedback signals from the actuator, such as the angle, speed, and current, in order to calculate the control voltage of the motor according to the target braking force value from the central control unit. The motor controller outputs the calculated voltage signal to the motor actuator, i.e., the motor body 21 in the wheel-side motor assembly, to drive the motor shaft 211 to move. When braking is required, the motor body 21 obtains an electromotive force opposite to that during driving, and brakes after being decelerated and increased in distance by the reducer. The electromagnet 224 can generate a corresponding clamping force according to the actual vehicle motion state, clamp the brake shaft 223, and thus transmit the braking torque to the motor shaft 211 through the coupling 5, thereby adjusting the braking force or realizing the parking function. In addition, the electronic mechanical brake 22 is composed of an electromagnet 224 and a mutual translational friction plate 221 and a rotational friction plate 222. After power is turned on, the translational friction plate 221 and the rotational friction plate 222 are coupled to assist the motor body to generate a braking torque. The magnitude and direction of the braking torque are coordinated and controlled by controlling the magnitude and direction of the current flowing through the electromagnet 224.

[0062] An electric vehicle comprises the drive axle with integrated braking function described in the present invention.

[0063] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A drive axle with integrated braking function, comprising a drive axle body and wheels (1) connected to both ends of the drive axle body, characterized in that: It comprises two wheel-side motor assemblies (2) arranged in the middle of the drive axle body and connected to the two wheels (1) respectively, the two wheel-side motor assemblies (2) being integrated into one body and used to independently control the driving or braking of the corresponding wheels (1); A single wheel-side motor assembly (2) comprises a motor body (21) and an electronic mechanical brake component (22); a power output end of the motor body (21) is drivingly connected to a wheel (1) via a reducer; and the electronic mechanical brake component (22) acts on a motor shaft (211) of the motor body (21) to brake the motor shaft (211) of the motor body (21); The reducer is a two-stage planetary gear reducer, the power output end of the motor body (21) is drivingly connected to the sun gear of the first-stage planetary gear reducer (3), the planet carrier of the first-stage planetary gear reducer (3) is drivingly connected to the sun gear of the second-stage planetary gear reducer (4), the planet carrier of the second-stage planetary gear reducer (4) is drivingly connected to the inner ring of the hub bearing (6), and the flange (61) of the outer ring of the hub bearing (6) is cooperatively connected to the rim (8) of the wheel (1); The wheel hub bearing (6) is a deep groove ball cylindrical roller wheel hub bearing.

2. The drive axle with integrated braking function according to claim 1, characterized in that: The electronic mechanical brake component (22) comprises a translation friction plate (221), a rotation friction plate (222), a drive assembly and a brake shaft (223); the brake shaft (223) is drivingly connected to a motor shaft (211) of a motor body (21); the rotation friction plate (222) is fixedly connected to the brake shaft (223) and the rotation friction plate (222) rotates with the brake shaft (223); the translation friction plate (221) is slidably connected to a housing of the motor body (21) and the translation friction plate (221) can move closer to or farther from the rotation friction plate (222) under the action of the drive assembly.

3. The drive axle with integrated braking function according to claim 2, characterized in that: The driving assembly comprises an electromagnet (224) and a magnet slider (225); the electromagnet (224) is fixed to the inner side of a housing of a motor body (21); the magnet slider (225) is arranged within the action range of the electromagnet (224); and the magnet slider (225) is fixedly connected to the translation friction plate (221); by adjusting the current magnitude and direction of the electromagnet (224), the magnet slider (225) is translated along the axial direction of the brake shaft (223), thereby driving the translation friction plate (221) to approach or move away from the rotation friction plate (222) and adjusting the coupling friction force of the translation friction plate (221) and the rotation friction plate (222).

4. The drive axle with integrated braking function according to claim 3, characterized in that: The driving assembly further comprises a return spring (226), one end of the return spring (226) being fixedly connected to the housing of the motor body (21), and the other end of the return spring (226) being fixedly connected to the magnet slider (225).

5. The drive axle with integrated braking function according to claim 3, characterized in that: The translational friction plate (221) and the rotational friction plate (222) are embedded with coils. When the motor body (21) is damaged or the translational friction plate (221) and the rotational friction plate (222) are damaged, the electromagnet (224) acts as a safety backup and cooperates with the coil to generate a braking torque. The magnitude and direction of the torque are coordinated and controlled by controlling the magnitude and direction of the current flowing through the coil.

6. The drive axle with integrated braking function according to claim 2, characterized in that: The brake shaft (223) is transmission-connected to the motor shaft (211) via a coupling (5).

7. The drive axle with integrated braking function according to claim 2, characterized in that: It also includes an inner seat ring (227) and an outer seat ring (228), wherein the inner seat ring (227) is spline-connected to the brake shaft (223), and the rotating friction plate (222) is fixed on the inner seat ring (227); the outer seat ring (228) is spline-connected to the inner wall of the motor housing of the motor body (21), and the outer seat ring (228) can move along the axial direction of the brake shaft (223), and the translational friction plate (221) is fixed on the outer seat ring (228).

8. The drive axle with integrated braking function according to claim 1 or 2, characterized in that: The motor body (21) is a brushless DC motor, which receives an action signal from a main controller, controls the motor shaft output, and generates a desired target rotation speed.

9. An electric vehicle, characterized in that: A drive axle with integrated braking function comprising any one of claims 1 to 8.

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