An Electric Wheel Structure for Overloaded Vehicles and Its Usage Method

Abstract

The present invention discloses a structure of an electric wheel for heavy-duty vehicles and its usage method, belonging to the technical field of electric vehicle drive. It includes a rim, on the inner surface of which a planetary reducer and a drum brake are connected. A cavity is arranged inside the drum brake, and a hub motor is installed in the cavity. The hub motor is connected to the planetary reducer through a motor shaft. The planetary reducer includes a sun gear, planet gears, a ring gear and a planetary reducer housing connected in sequence. The sun gear is connected to the motor shaft, and the planetary reducer housing is connected to the rim. An outer motor housing, an outer motor end cover and an inner motor end cover are arranged outside the hub motor. Both sides of the outer motor housing are respectively connected to the outer motor end cover and the inner motor end cover. The drum brake includes a brake drum, brake shoes and a brake wheel cylinder connected in sequence. The brake wheel cylinder is connected to the inner motor end cover, the brake drum is connected to the rim, and the outer motor housing is connected to the brake drum, reducing the design and assembly processes of independent components, thereby reducing the manufacturing cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicle drive, and specifically relates to a structure of an electric wheel for heavy-duty vehicles and its usage method. Background Art

[0002] The design of electric wheels has gradually emerged with the development of the electric vehicle industry. As an environmentally friendly and efficient means of transportation, electric vehicles have significantly different driving methods from traditional internal combustion engine vehicles. The core of electric wheel design lies in in-wheel motor technology, which integrates power, transmission, and braking devices entirely within the wheel hub, closely combines power output with the wheel, eliminates the traditional drive shaft and differential, simplifies the vehicle structure, and improves the overall vehicle's power transmission efficiency; since each electric wheel can be independently controlled, the vehicle's maneuverability is greatly improved, especially in working conditions such as turning and lane changing.

[0003] Currently, some schools pay more attention to thermal management, control system optimization, and industrial application, while enterprises focus on the integration of the whole vehicle and large-scale production, and their electric wheels have been used in some high-end new energy vehicle models. Protean Electric's electric wheels have been tested on multiple prototype vehicles, showing good maneuverability and power response. Generally speaking, the future of electric wheel technology lies in further improving its energy efficiency, reducing manufacturing costs, solving heat dissipation problems, and deeply integrating with autonomous driving technology.

[0004] Due to the advantages of disc brakes in their own design characteristics, disc brakes are currently the commonly used brakes in electric wheels. Although they can enable the vehicle to maintain good braking performance at relatively high speeds, the production cost is relatively high, and most domestic heavy-duty vehicles still do not use disc brakes. Drum brakes have good braking performance under low-speed working conditions, are structurally strong and wear-resistant, and have low production costs or replacement costs. For heavy-duty vehicles with relatively low speeds in daily operating conditions, the design solution of integrating drum brakes into the interior of heavy-duty vehicle electric wheels is a beneficial technical solution that saves space and is structurally compact. However, the drum brakes of heavy-duty vehicles or special-purpose vehicles may be larger to withstand higher loads and braking requirements, which violates the highly integrated principle of electric wheels. Therefore, how to integrate drum brakes, in-wheel motors, and reducers into the rim in a good combination manner is a difficult point.

[0005] At present, there are already patent applications adopting the electric wheel scheme with an integrated drum brake. For example, the Chinese patent application with the publication number "CN109823163A" adopts an integrated scheme in which a planetary reducer, an in-rotor hub motor and a drum brake are arranged side by side inside the rim, and the hub motor is sandwiched between the planetary reducer and the drum brake. This scheme is not conducive to dissipating the heat generated by the hub motor when outputting the driving torque. A large amount of heat is also generated during friction braking of the drum brake, which further increases the temperature of the motor, resulting in serious motor temperature rise. The layout scheme of the drum brake is not ideal enough. Especially for heavy-duty vehicles, the brake drum usually needs to be designed larger. A larger brake drum can provide a larger friction surface area, thereby enhancing the braking effect. In addition, a larger brake drum also helps to better dissipate heat and reduce brake fade (weakening of braking efficiency) caused by overheating. Therefore, for the electric wheel of a heavy-duty vehicle, it is difficult to integrate a larger drum brake, a hub motor and a reducer into the electric wheel interior in a good combination manner on the premise of ensuring the heat dissipation efficiency of the hub motor and the drum brake. Summary of the Invention

[0006] The present invention provides a heavy-duty vehicle electric wheel structure and its usage method, which solves the problem that for the electric wheel of a heavy-duty vehicle, it is difficult to integrate a larger drum brake, a hub motor and a reducer into the electric wheel interior in a good combination manner on the premise of ensuring the heat dissipation efficiency of the hub motor and the drum brake.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A heavy-duty vehicle electric wheel structure includes a rim. A planetary reducer and a drum brake are connected to the inner surface of the rim. A cavity is provided inside the drum brake, and a hub motor is installed in the cavity. The hub motor is connected to the planetary reducer through a motor shaft;

[0009] The planetary reducer includes a sun gear, planet gears, a ring gear and a planetary reducer housing connected in sequence. The sun gear is connected to the motor shaft. The planetary reducer housing is connected to the rim. A motor housing, a motor outer end cover and a motor inner end cover are provided outside the hub motor. The two sides of the motor housing are respectively connected to the motor outer end cover and the motor inner end cover. The drum brake includes a brake drum, brake shoes and a brake wheel cylinder connected in sequence. The brake wheel cylinder is connected to the motor inner end cover. The brake drum is connected to the rim. The motor housing is connected to the brake drum.

[0010] Preferably, a support arm is provided on the motor outer end cover. The support arm is connected to the vehicle axle, and a reinforcing rib is provided at the end of the support arm.

[0011] Preferably, the motor housing is connected to the brake drum through cylindrical roller bearings. Positioning shoulders are provided on the motor housing and the outer end cover of the motor. The positioning shoulders of the motor housing and the outer end cover of the motor fix the inner ring of the cylindrical roller bearing, and the outer ring of the cylindrical roller bearing rotates with the brake drum.

[0012] Preferably, on one side of the motor housing close to the inner end cover of the motor, there are ear plates. The ear plates are fixedly connected to the inner end cover of the motor by screws. On the upper and lower sides of the outer side of the motor housing close to the inner end cover of the motor, there are brake shoe support blocks for supporting and fixing the axial position of the brake shoes on the surface of the motor housing.

[0013] Preferably, at both ends of the brake wheel cylinder, there are brake wheel cylinder H-shaped keys. At both ends of the brake shoes, there are grooves. The brake wheel cylinder H-shaped keys cooperate with the grooves on the brake shoes to fix the axial and radial positions of the brake shoes. On one side of the grooves at both ends of the brake shoes, there is a return spring. The return spring is close to the center of the brake shoes. A friction lining is provided between the inner surfaces of the brake shoes and the brake drum.

[0014] Preferably, a planetary gear positioning column is connected to the inner end cover of the motor. A first planet carrier and a second planet carrier arranged in parallel are connected to the planetary gear positioning column. A planetary gear bearing is connected between the first planet carrier and the second planet carrier. The planetary gear bearing is connected to the planetary gear.

[0015] Preferably, planetary gear bearing positioning steps are provided on both the first planet carrier and the second planet carrier. The planetary gear bearing positioning steps on the first planet carrier and the second planet carrier pass through the inner ring of the planetary gear bearing to support and fix the inner ring of the planetary gear bearing. A through hole is provided at the center position of the first planet carrier for the motor shaft to pass through.

[0016] Preferably, a positioning column groove is provided on the planetary gear positioning column. An elastic snap ring is provided on the positioning column groove. The elastic snap ring is arranged outside the first planet carrier and the second planet carrier to fix the positions of the first planet carrier and the second planet carrier.

[0017] Preferably, a rectangular groove is provided on the outer circle of the ring gear. An L-shaped key is provided on the inner surface of the planetary reducer housing. The rectangular groove cooperates with the L-shaped key to fix the axial position of the ring gear in the planetary reducer housing.

[0018] A usage method of a heavy-duty vehicle electric wheel structure includes:

[0019] When a heavy-duty vehicle is in motion, the in-wheel motor transmits the required driving torque to the sun gear through the motor shaft. The rotation of the sun gear drives the planet gears to rotate about their own axes, and the rotation of the planet gears drives the ring gear to rotate. The rotation of the ring gear drives the rotation of the planetary reducer housing, thereby transmitting power to the rim. The rotation of the rim drives the rotation of the brake drum. At this time, no braking torque is generated on the brake drum, and the internal drive part and brake part of the electric wheel of the heavy-duty vehicle operate normally. When the heavy-duty vehicle brakes, the brake wheel cylinder outputs a braking thrust, which is transmitted by the brake wheel cylinder to the brake shoes, causing the brake shoes to closely fit the brake drum, generating frictional force, forcing the rotational speed of the brake drum to decrease, and finally causing the rotational speed of the rim to decrease, achieving the purpose of vehicle deceleration.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a structure of an electric wheel for a heavy-duty vehicle, including a rim. A planetary reducer and a drum brake are connected to the inner surface of the rim. A cavity is provided inside the drum brake, and an in-wheel motor is installed in the cavity. The in-wheel motor is connected to the planetary reducer through a motor shaft. By integrating the installation of the in-wheel motor, the drum brake, and the planetary reducer inside the rim, the overall weight of the vehicle is reduced through integrated design. The planetary reducer includes a sun gear, planet gears, a ring gear, and a planetary reducer housing connected in sequence. The sun gear is connected to the motor shaft, and the planetary reducer housing is connected to the rim. An outer motor housing, an outer motor end cover, and an inner motor end cover are provided outside the in-wheel motor. The two sides of the outer motor housing are respectively connected to the outer motor end cover and the inner motor end cover. The drum brake includes a brake drum, brake shoes, and a brake wheel cylinder connected in sequence. The brake wheel cylinder is connected to the inner motor end cover, the brake drum is connected to the rim, and the outer motor housing is connected to the brake drum, reducing the design and assembly processes of independent components, thereby reducing the manufacturing cost. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the overall structure of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0022] Figure 2 It is a cross-sectional view of the overall structure of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0023] Figure 3 It is a schematic diagram of the overall structure of the in-wheel motor of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0024] Figure 4 It is a schematic diagram of the inner end cover structure of the in-wheel motor of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0025] Figure 5 It is a schematic diagram of the outer end cover structure of the in-wheel motor of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0026] Figure 6 It is a schematic diagram of the internal structure of the drum brake of the electric wheel for a heavy-duty vehicle proposed by the present invention;

[0027] Figure 7 Schematic structural diagram of the brake wheel cylinder of the electric wheel drum brake for heavy-duty vehicles proposed by the present invention;

[0028] Figure 8 Schematic structural diagram of the brake drum and its internal structure of the electric wheel drum brake for heavy-duty vehicles proposed by the present invention;

[0029] Figure 9 Schematic structural diagram of the planetary reducer of the electric wheel for heavy-duty vehicles proposed by the present invention;

[0030] Figure 10 Schematic structural diagram of the planet carrier of the planetary reducer of the electric wheel for heavy-duty vehicles proposed by the present invention;

[0031] Figure 11 Schematic structural diagram of the housing of the planetary reducer of the electric wheel for heavy-duty vehicles proposed by the present invention;

[0032] Figure 12 Schematic structural diagram of the rim of the electric wheel for heavy-duty vehicles proposed by the present invention;

[0033] In the figure: 1. Outer end cover of the motor; 2. Cylindrical roller bearing; 3. Brake drum; 4. Brake shoe; 5. Rim; 6. Housing of the planetary reducer; 7a. First planet carrier; 7b. Second planet carrier; 8. Planet gear positioning column; 9. Motor shaft; 10. Sun gear; 11. Planet gear; 12. Planet gear bearing; 13. Snap ring; 14. End cover of the planetary reducer; 15. Ring gear; 16. Inner end cover of the motor; 17. Brake wheel cylinder; 18. Return spring; 19. Motor housing; 20. Motor stator; 21. Brake shoe support block; 22. Threaded hole on the inner end cover of the motor; 23. Threaded hole of the brake wheel cylinder; 24. Friction lining; 25. H-shaped key of the brake wheel cylinder. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0036] It should be noted that like reference numerals and letters denote like items in the following figures. Therefore, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0038] As Figure 1 shown, the present invention provides a structure of an electric wheel for a heavy-duty vehicle, which includes a rim 5. A planetary reducer and a drum brake are connected to the inner surface of the rim 5. A cavity is provided inside the drum brake, and a hub motor is installed in the cavity. The hub motor is connected to the planetary reducer through a motor shaft 9.

[0039] The planetary reducer includes a sun gear 10, a planet gear 11, a ring gear 15 and a planetary reducer housing 6 connected in sequence. The sun gear 10 is connected to the motor shaft 9, and the planetary reducer housing 6 is connected to the rim 5. An outer motor housing 19, an outer motor end cover 1 and an inner motor end cover 16 are provided outside the hub motor. The two sides of the outer motor housing 19 are respectively connected to the outer motor end cover 1 and the inner motor end cover 16. The drum brake includes a brake drum 3, brake shoes 4 and a brake wheel cylinder 17 connected in sequence. The brake wheel cylinder 17 is connected to the inner motor end cover 16, the brake drum 3 is connected to the rim 5, and the outer motor housing 19 is connected to the brake drum 3.

[0040] This electric wheel structure integrates a hub motor, a drum brake, and a planetary reducer, and adopts a new combined integrated design method. Specifically, the brake backing plate of the drum brake is integrally designed with the inner end cover 16 of the motor. The brake wheel cylinder 17 of the drum brake is fixed to the inner end cover 16 of the motor by screws. The hub motor runs through the cavity of the drum brake. The axial and radial positions of the brake shoe 4 are jointly determined by the brake wheel cylinder H-shaped keys 25 at both ends of the brake wheel cylinder 17 and the brake shoe support block 21 on the outer side of the hub motor housing 19. A cylindrical roller bearing 2 is sleeved outside the motor housing 19. The outer ring of the cylindrical roller bearing 2 is closely attached to the inner surface of the brake drum 3 of the drum brake. The axial and radial positions of the hub motor in the cavity of the drum brake are fixed by the cylindrical roller bearing 2. There are two upper and lower support arms on the outer end cover 1 of the motor. The hub motor is fixed to the vehicle axle through the support arms. The motor shaft 9 is engaged with the keyway of the sun gear 10 through the spline at the shaft end to achieve power transmission. A planetary gear positioning post 8 is connected to the inner end cover 16 of the motor. A first planetary carrier 7a and a second planetary carrier 7b arranged in parallel are connected to the planetary gear positioning post 8. The positions of the first planetary carrier 7a and the second planetary carrier 7b are fixed on the planetary gear positioning post 8 outside the inner end cover 16 of the motor by snap rings 13. The torque output by the hub motor is transmitted to the ring gear 15 through the sun gear 10 and the planet gears 11. The ring gear 15 is connected to the planetary reducer end cover 14 through a rectangular keyway. The planetary reducer housing 6 is fixedly connected to the wheel rim 5 by screws. This design successfully solves the technical problem that it is difficult to arrange a drum brake, a hub motor, and a planetary reducer in the wheel rim 5 at the same time during the integrated design of the electric wheel for heavy-duty vehicles. At the same time, it ensures the driving force and braking force required for heavy-duty vehicles.

[0041] The hub motor is installed in the cavity formed by the drum brake and serves as the driving force source of the electric wheel. The hub motor consists of an outer end cover 1 of the motor, an inner end cover 16 of the motor, a motor housing 19, a motor shaft 9, etc. The inner end cover 16 and the outer end cover 1 of the motor are both fixedly connected to the motor housing 19 by screws. There are two support arms on the outer end cover 1 of the motor. The support arms are used to connect the hub motor to the vehicle axle. At the same time, there are two reinforcing ribs at the ends of the support arms to improve the load-bearing capacity of the support arms. The outer end cover 1 of the motor also has a positioning shoulder for fixing the inner ring of the cylindrical roller bearing 2. At the same time, the positioning shoulder strengthens the load-bearing capacity of the outer end cover 1 of the motor. A planetary gear positioning post 8 is provided on the outer side of the inner end cover 16 of the motor. There are six ear plates on one side of the motor housing 19 close to the inner end cover 16. The six ear plates are fixedly connected to the inner end cover 16 of the motor by screws. On both the upper and lower sides of the part of the outer side of the motor housing 19 close to the inner end cover 16, there are brake shoe support blocks 21 for supporting and fixing the axial position of the brake shoe 4 on the surface of the motor housing 19. There is a shoulder on one side of the motor housing 19 close to the outer end cover 1 of the motor. The shoulder and the positioning shoulder on the outer end cover 1 of the motor jointly fix the inner ring of the cylindrical roller bearing 2.

[0042] The drum brake is used to provide the braking torque required for the electric wheel. The drum brake consists of two left and right brake shoes 4, friction linings 24, return springs 18, a brake drum 3, and two upper and lower brake wheel cylinders 17. The brake wheel cylinder 17 is fixedly connected to the inner end cover 16 of the motor by screws, and the axial position of the installation of the brake shoe 4 is determined by fixing the position of the brake wheel cylinder 17. At the same time, the axial and radial positions of the two left and right brake shoes 4 are also fixed by the support blocks on the outer side of the motor housing 19; the return springs 18 are installed at both ends of the brake shoe 4, and the installation positions are kept at a certain distance from the hub motor and the brake wheel cylinder 17 to avoid frictional losses; one side of the brake drum 3 is fixedly connected to the rim 5 and the planetary reducer housing 6 by screws, and the other side of the brake drum 3 is provided with an L-shaped positioning shoulder for fixing the axial position of the cylindrical roller bearing 2, and the inner side of the brake drum 3 is closely attached to the outer ring of the cylindrical roller bearing 2. Among them, the inner ring of the cylindrical roller bearing 2 is fixed, and the outer ring rotates with the brake drum 3. At the same time, six reinforcing ribs are provided on the outer side of the brake drum 3 to improve the anti-deformation and radial load-bearing capacity of the brake drum 3.

[0043] The planetary reducer is used to convert the high-speed low-torque output of the hub motor into a low-speed high-torque output to the rim 5. The planetary reducer consists of a sun gear 10, planetary gears 11, a planetary carrier, a ring gear 15, a planetary reducer housing 6, a planetary reducer end cover 14, etc. A spline key groove is opened inside the sun gear 10 for mating with the spline on the motor shaft 9; the external teeth of the planetary gear 11 mesh with the external teeth of the sun gear 10, and the rotation of the sun gear 10 drives the planetary gear 11 to rotate around its own axis. The planetary carrier includes a first planetary carrier 7a and a second planetary carrier 7b. A planetary gear bearing 12 is connected between the first planetary carrier 7a and the second planetary carrier 7b. The planetary gear 11 is in interference fit with the planetary gear bearing 12. Planetary gear bearing positioning steps are provided on both the first planetary carrier 7a and the second planetary carrier 7b. The planetary gear bearing positioning steps on the first planetary carrier 7a and the second planetary carrier 7b pass through the inner ring of the planetary gear bearing 12 to support and fix the inner ring of the planetary gear bearing 12, and the outer ring of the planetary gear bearing 12 rotates with the planetary gear 11; the internal teeth of the ring gear 15 mesh with the external teeth of the planetary gear 11 for power transmission. A rectangular groove is provided on the outer circle of the ring gear 15 for mating with the L-shaped key provided on the inner surface of the planetary reducer housing 6, so that the torque on the ring gear 15 is output to the planetary reducer housing 6. At the same time, the L-shaped key and the planetary reducer end cover 14 jointly determine the axial position of the ring gear 15 in the planetary reducer housing 6. The planetary reducer end cover 14 is fixedly connected to the planetary reducer housing 6 by screws, and a positioning cylinder is provided on the inner surface of the planetary reducer end cover 14 for fixing the axial position of the ring gear 15.

[0044] An inner flange is provided at the middle position of the inner surface of the rim 5. The inner flange is used to fixedly connect the rim 5 to the brake drum 3 of the drum brake and the planetary reducer housing 6 by screws.

[0045] The brake wheel cylinder 17 is composed of a cylinder block and a connecting column. An ear plate is provided on the lower surface of the connecting column, and the ear plate is fixedly connected to the inner end cover 16 of the motor by screws, thereby fixing the position of the brake wheel cylinder 17.

[0046] Wherein, H-shaped keys 25 of the brake wheel cylinder are provided at both ends of the brake wheel cylinder 17. The H-shaped keys 25 of the brake wheel cylinder are used to clamp the brake shoe 4 to fix the axial position of the brake shoe 4. At the same time, the H-shaped keys 25 of the brake wheel cylinder ensure the stable output of the required braking force of the brake wheel cylinder 17.

[0047] A support block is provided at the middle position of the motor housing 19. The support block is used to fix the axial and radial positions of the brake shoe 4; the position of the brake shoe 4 is jointly determined by the support block and the H-shaped keys 25 provided at both ends of the brake wheel cylinder 17.

[0048] Wherein, the return springs 18 in the drum brake are distributed on both sides of the brake shoe 4 and are far away from the brake wheel cylinder 17 and the motor housing 19. The return springs 18 are used to make the brake shoe 4 closely fit with the support block and the H-shaped keys 25 of the brake wheel cylinder 17 when the brake shoe 4 does not receive the thrust generated by the brake wheel cylinder 17, thereby fixing the radial and axial positions of the brake shoe 4 in the drum brake.

[0049] An outer flange plate is provided at one end of the brake drum 3. The outer flange plate is fixedly connected to the inner flange provided on the inner surface of the rim 5 by screws; the other end of the brake drum 3 is an L-shaped positioning shoulder, and the positioning shoulder is used to fix the outer ring of the cylindrical roller bearing 2 on the brake drum 3, so that the outer ring of the cylindrical roller bearing 2 is closely attached to the brake drum 3; six reinforcing ribs are provided on the outer side of the brake drum 3 to increase the anti-deformation and radial load-bearing capacity of the brake drum 3.

[0050] Two support arms, upper and lower, are provided on the outer side of the outer end cover 1 of the motor. Two reinforcing ribs are provided at the end of each support arm; a positioning shoulder for fixing the inner ring of the cylindrical roller bearing 2 is provided on the outer end cover 1 of the motor. The positioning shoulder not only cooperates with the shaft shoulder on the motor housing 19 to fix the inner ring of the cylindrical roller bearing 2, but also strengthens the radial load-bearing capacity of the outer end cover 1 of the motor.

[0051] A planetary gear positioning column 8 is provided on the outer side of the inner end cover 16 of the motor. Two positioning column grooves are provided on the planetary gear positioning column 8. The positioning column grooves are used to place the snap ring 13 for fixing the relative position of the planet carrier on the positioning column.

[0052] The planetary speed reducer includes a first planet carrier 7a and a second planet carrier 7b. The first planet carrier 7a and the second planet carrier 7b interact and cooperate to fix the planet gears 11 and the planet gear bearings 12. Both the first planet carrier 7a and the second planet carrier 7b are provided with three positioning steps, and each positioning step fixes a planet gear 11 and a planet gear bearing 12. The positioning steps on the first planet carrier 7a and the second planet carrier 7b are opposite to each other, supporting and fixing the planet gear bearings 12, so that the inner rings of the planet gear bearings 12 remain stationary and the outer rings rotate. The planet gears 11 are in interference fit with the outer rings of the planet gear bearings 12 through their inner circles, thereby realizing the self-rotation of the planet gears 11 around their own axes.

[0053] One end of the planetary speed reducer housing 6 is provided with an inner flange for being fixedly connected by screws to the inner flange provided on the inner surface of the rim 5 and the inner flange provided at one end of the brake drum 3. The other end of the planetary speed reducer housing 6 is provided with a positioning shoulder, and the axial position of the planetary speed reducer housing 6 relative to the rim 5 is fixed through this positioning shoulder. The inner surface of the planetary speed reducer housing 6 is provided with an L-shaped key, and the L-shaped key is used to cooperate with a rectangular groove provided on the outer circumferential surface of the ring gear 15. At the same time, the L-shaped key cooperates with a flange on the inner side of the planetary speed reducer end cover 14 to jointly fix the axial position of the ring gear 15 in the planetary speed reducer housing 6.

[0054] Another embodiment of the present invention provides a structure of an electric wheel for a heavy-duty vehicle, as Figures 1 - 12 shown, including a hub motor, a drum brake, a planetary speed reducer, and a rim 5. The hub motor includes a motor outer end cover 1, a motor housing 19, a motor stator 20, a motor shaft 9, etc.; the drum brake includes a brake drum 3, brake shoes 4, a brake wheel cylinder 17, and a return spring 18; the planetary speed reducer includes a sun gear 10, planet gears 11, a ring gear 15, a planetary speed reducer housing 6, a first planet carrier 7a, a second planet carrier 7b, an elastic snap ring 13, planet gear bearings 12, and a planetary speed reducer end cover 14.

[0055] The hub motor is installed inside the rim 5, as Figure 1 , Figure 2 shown. The hub motor is arranged in the left half of the rim 5 and is located inside the cavity formed by the brake drum 3 and the brake shoes 4 of the drum brake.

[0056] As Figure 3As shown in the figure, the outer end cover 1 of the in-wheel motor is fixedly connected to the motor housing 19 by six screws. There is a shoulder in the middle of the motor housing 19 for positioning the axial position of the cylindrical roller bearing 2 on the motor housing 19. At the position of the motor housing 19 close to the inner end cover 16 of the motor, there are two symmetric brake shoe support blocks 21 up and down for supporting and fixing the radial and axial positions of the brake shoes. On the inner end cover 16 of the motor, there are a brake wheel cylinder threaded hole 23 and an inner end cover threaded hole 22 of the motor. The brake wheel cylinder 17 is fixedly connected to the inner end cover 16 of the motor through the brake wheel cylinder threaded hole 23, and the inner end cover 16 of the motor is fixedly connected to six mounting ears on the motor housing 19 through the inner end cover threaded hole 22 of the motor. As Figure 4 shown, on the right side of the inner end cover 16 of the motor, there are three planetary gear positioning posts 8. There are two positioning post grooves on the planetary gear positioning posts 8 for placing the snap ring 13 to fix the axial position of the planet carrier 7 on the planetary gear positioning posts 8 through the snap ring 13. At the end of the motor shaft 9, there is a spline for mating with the keyway inside the sun gear 10 to achieve power transmission.

[0057] As Figure 5 shown, in this embodiment, there are two support arms on the outer end cover 1 of the motor. The support arms are used to connect the electric wheel of the heavy-duty vehicle to the axle of the vehicle, so as to transfer the weight of the vehicle body and the force on the vehicle body to the electric wheel of the heavy-duty vehicle. There are two reinforcing ribs at the end of each of the two support arms for improving the load-bearing capacity of the support arms. And there is a positioning shoulder on the right side of the support arm for fixing the inner ring of the cylindrical roller bearing 2 and also strengthening the load-bearing capacity of the outer end cover 1 of the motor, effectively avoiding deformation, cracking or other structural failures of the outer end cover 1 of the motor due to excessive loading, thus ensuring the safe operation of the electric wheel of the heavy-duty vehicle proposed by the present invention and extending its service life.

[0058] As Figure 1 、 Figure 2 、 Figure 6 and Figure 8 shown, the drum brake is arranged around the motor housing 19 and is located inside the wheel rim 5 at the same time. The brake backing plate required in the drum brake is replaced by the inner end cover 16 of the motor. The brake drum 3 in the drum brake is fixedly connected to the wheel rim 5 by six screws and rotates with the wheel rim 5.

[0059] As Figure 6 shown, the internal structure of the brake drum 3 of the drum brake is composed of two brake wheel cylinders 17 up and down, two brake shoes 4 left and right, friction linings 24 and return springs 18. As Figure 7As shown in the figure, the ear plate provided on the brake wheel cylinder 17 is fixedly connected to the inner end cover 16 of the motor by screws. H-shaped keys 25 of the brake wheel cylinder are provided at both ends of the brake wheel cylinder 17. The H-shaped keys 25 of the brake wheel cylinder are engaged with the grooves provided at both ends of the brake shoe 4 to fix the axial and radial positions of the brake shoe 4. At the same time, the brake shoe 4 is further fixed in the axial and radial directions by being engaged with the grooves provided on the brake shoe support block 21, ensuring that the required braking force output by the brake wheel cylinder 17 is safer and more stable.

[0060] As Figure 8 shown in the figure, six reinforcing ribs and six threaded holes are provided on the brake drum 3. The six threaded holes are used for fixedly connecting with the rim 5 by screws; the inner ring of the cylindrical roller bearing 2 is jointly fixed by the positioning shoulder provided on the outer end cover 1 of the motor and the shoulder provided on the motor housing 19, so that the inner ring of the cylindrical roller bearing 2 is fixed and the outer ring rotates; the force and torque borne by the support arm of the outer end cover 1 of the motor are transferred to the brake drum 3 by the cylindrical roller bearing 2, and then the brake drum 3 is transferred to the surface of the rim 5; at the same time, the six reinforcing ribs provided on the surface of the brake drum 3 can ensure that the brake drum 3 has greater anti-deformation and load-bearing capacities in the radial direction.

[0061] The planetary reducer is driven by the sun gear 10, with the planetary gear 11 fixed and the ring gear 15 rotating. The planetary reducer is integrally arranged in the right half part inside the rim 5. As Figure 1 、 Figure 2 shown in the figure, the planetary reducer housing 6 is fixedly connected to the rim 5 and the brake drum 3 by screws, so that the torque output by the hub motor is decelerated and increased in torque by the planetary reducer and then transmitted to the rim 5, realizing the movement of the electric wheel-driven heavy vehicle described in the present invention.

[0062] As Figure 9 shown in the figure, the inside of the planetary reduction housing is composed of a ring gear 15, a planetary gear 11, a first planetary carrier 7a, a second planetary carrier 7b, a planetary gear positioning post 8, and an elastic snap ring 13. As Figure 2 and Figure 9 shown in the figure, the difference between the first planetary carrier 7a and the second planetary carrier 7b is that: there is a through hole in the middle of the first planetary carrier 7a, and the motor shaft 9 passes through the through hole in the middle of the first planetary carrier 7a, so that the torque output by the hub motor is transmitted to the sun gear 10, and the sun gear 10 rotates to drive the planetary gear 11 to rotate around its own axis. At the same time, the self-rotation of the planetary gear 11 drives the rotation of the ring gear 15. The ring gear 15 is connected to the planetary reducer housing 6 through a keyway. Finally, the ring gear 15 drives the planetary reducer housing 6 to rotate, and the planetary reducer housing 6 drives the rim 5 to rotate, enabling the vehicle to drive normally.

[0063] As Figure 10As shown, three planetary gear bearing positioning steps are provided on the first planetary carrier 7a. The planetary gear bearing positioning steps support and fix the inner ring of the planetary gear bearing 12, determining the axial position of the planetary gear bearing 12 between the two planetary carriers. The planetary gear 11 is in interference fit with the planetary gear bearing 12, thereby fixing the axial position of the planetary gear 11; as Figure 4 On the planetary gear positioning post 8 shown, two positioning post grooves are provided. The two positioning post grooves cooperate with the two snap rings 13 to determine the relative position of the first planetary carrier 7a and the second planetary carrier 7b on the planetary gear positioning post 8.

[0064] As Figure 11 shown, an L-shaped rectangular key is provided on the inner circular surface of the planetary reducer housing 6 for mating with a rectangular groove provided on the outer circular surface of the ring gear 15; the ring gear 15 is in close contact with the left side of the L-shaped rectangular key. At the same time, as Figure 2 shown, the planetary reducer end cover 14 is in close contact with the right side of the ring gear 15, and the two together determine the relative position of the ring gear 15 in the planetary reducer housing 6.

[0065] The working principle of a heavy-duty vehicle electric wheel structure of the present invention will be introduced below.

[0066] When the heavy-duty vehicle is running, the hub motor transmits the required driving torque to the sun gear 10 through the motor shaft 9. The rotation of the sun gear 10 drives the planetary gear 11 to rotate self. The self-rotation of the planetary gear 11 drives the ring gear 15 to rotate. The rotation of the ring gear 15 drives the planetary reducer housing 6 to rotate, and finally the planetary reducer housing 6 drives the rim 5 to rotate, realizing power transmission; the rotation of the rim 5 drives the rotation of the brake drum 3, but at this time the brake drum 3 does not generate any braking torque. Therefore, the internal drive part and the braking part of the heavy-duty vehicle electric wheel operate normally; when the heavy-duty vehicle brakes, the brake wheel cylinder 17 outputs the required braking thrust. The brake wheel cylinder H-shaped keys 25 at both ends of the brake wheel cylinder output the braking thrust smoothly to the brake shoe 4, so that the friction lining 24 on the surface of the brake shoe 4 is in close contact with the brake drum 3, generating friction force, forcing the rotation speed of the brake drum 3 to decrease, and finally making the rotation speed of the rim 5 decrease, so as to achieve the purpose of decelerating the heavy-duty vehicle.

[0067] Secondly, the internal force condition of a heavy-duty vehicle electric wheel structure of the present invention will be analyzed.

[0068] The rim 5 is subjected to forces in the three directions of horizontal, longitudinal and vertical from the ground. The forces in the three directions of horizontal, longitudinal and vertical from the ground are sequentially transmitted through the brake drum 3, the cylindrical roller bearing 2, the motor housing 19, the upper and lower support arms of the motor outer end cover 1, and finally the motor outer end cover 1 transmits the force from the ground to the vehicle axle of the heavy-duty vehicle through the upper and lower support arms.

[0069] Finally, the installation method of a heavy-duty vehicle electric wheel structure of the present invention will be introduced.

[0070] The installation method of the electric wheel of the heavy-duty vehicle described in the present invention is divided into two parts: The first part is the installation of the hub motor and the drum brake. First, install the motor housing 19 of the hub motor and the inner end cover 16 of the motor. Secondly, install the brake wheel cylinder 17 on the inner end cover 16 of the motor by screws. Install the two brake shoes 4 in the grooves of the brake shoe support blocks 21 provided on the surface of the motor housing 19. At the same time, fit the grooves at both ends of the brake shoe 4 with the brake wheel cylinder H-shaped keys 25 at both ends of the brake wheel cylinder 17, and install the return spring 18. Fit the cylindrical roller bearing 2 tightly with the shoulder on the surface of the motor housing 19. Finally, install the brake drum 3 so that the left side and the inner surface of the brake drum 3 are tightly fitted with the left side and the outer ring of the cylindrical roller bearing 2, and install the outer end cover 1 of the motor. Connect the hub motor, the drum brake and the rim 5 by screws; The second part is the installation of the planetary reducer. First, install the first planetary carrier 7a and the snap ring 13 on the planetary gear positioning post 8. Next, install the sun gear 10, the three planetary gear bearings 12, the planetary gears 11, and the ring gear 15 in sequence. Install the second planetary carrier 7b and another snap ring 13. Finally, install the planetary reducer housing 6, the rim 5, the brake drum 3 and the planetary reducer end cover 14.

Claims

1. A heavy-duty vehicle electric wheel structure, characterized in that: It comprises a wheel rim (5), the inner surface of which is connected to a planetary reducer and a drum brake, the drum brake is provided with a cavity inside, a wheel hub motor is installed in the cavity, and the wheel hub motor is connected to the planetary reducer via a motor shaft (9); The planetary reducer comprises a sun gear (10), a planetary gear (11), a gear ring (15) and a planetary reducer housing (6) which are connected in sequence, the sun gear (10) is connected to the motor shaft (9), the planetary reducer housing (6) is fixedly connected to the wheel rim (5), a motor housing (19), a motor outer end cover (1) and a motor inner end cover (16) are arranged on the outside of the wheel hub motor, and the two sides of the motor housing (19) are respectively connected to the motor outer end cover (1) and the motor inner end cover (16), the drum brake comprises a brake drum (3), a brake shoe (4) and a brake wheel cylinder (17) which are connected in sequence, the brake wheel cylinder (17) is connected to the motor inner end cover (16), the brake drum (3) is fixedly connected to the wheel rim (5), and the motor housing (19) is rotatably connected to the brake drum (3); A planetary gear positioning column (8) is connected to the inner end cover (16) of the motor, a first planet carrier (7a) and a second planet carrier (7b) arranged in parallel are connected to the planetary gear positioning column (8), a planetary wheel bearing (12) is connected between the first planet carrier (7a) and the second planet carrier (7b), and the planetary wheel bearing (12) is connected to the planetary wheel (11).

2. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: The motor outer end cover (1) is provided with a support arm, the support arm is connected to the axle of the vehicle, and a reinforcing rib is provided at the end of the support arm.

3. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: The motor housing (19) is connected to the brake drum (3) via a cylindrical roller bearing (2); positioning shoulders are provided on the motor housing (19) and the motor outer end cover (1); the positioning shoulders of the motor housing (19) and the motor outer end cover (1) fix the inner ring of the cylindrical roller bearing (2); and the outer ring of the cylindrical roller bearing (2) rotates with the brake drum (3).

4. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: An ear plate is provided on one side of the motor housing (19) close to the motor inner end cover (16), and the ear plate is fixedly connected to the motor inner end cover (16) by screws. Brake shoe support blocks (21) are provided on both upper and lower sides of the outer side of the motor housing (19) close to the motor inner end cover (16), for supporting and fixing the axial position of the brake shoe (4) on the surface of the motor housing (19).

5. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: The two ends of the brake wheel cylinder (17) are provided with brake wheel cylinder H-shaped keys (25), and the two ends of the brake shoe (4) are provided with grooves. The brake wheel cylinder H-shaped keys (25) cooperate with the grooves on the brake shoe (4) to fix the axial and radial positions of the brake shoe (4). A return spring (18) is installed on one side of the grooves at both ends of the brake shoe (4), and the return spring (18) is close to the center of the brake shoe (4). A friction lining (24) is provided between the brake shoe (4) and the inner surface of the brake drum (3).

6. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: The first planet carrier (7a) and the second planet carrier (7b) are both provided with planetary wheel bearing positioning steps, the planetary wheel bearing positioning steps on the first planet carrier (7a) and the second planet carrier (7b) pass through the inner ring of the planetary wheel bearing (12) and are used to support and fix the inner ring of the planetary wheel bearing (12), and a through hole is provided at the center position of the first planet carrier (7a) for the motor shaft (9) to pass through.

7. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: The planetary gear positioning column (8) is provided with a positioning column groove, the positioning column groove is provided with an elastic clamping ring (13), and the elastic clamping ring (13) is arranged outside the first planet carrier (7a) and the second planet carrier (7b).

8. The electric wheel structure for a heavy-duty vehicle according to claim 1, characterized in that: A rectangular groove is provided on the outer circle of the gear ring (15), and an L-shaped key is provided on the inner surface of the planetary reducer housing (6).

9. A method for using a heavy-duty vehicle electric wheel structure, characterized in that: A heavy-duty vehicle electric wheel structure according to any one of claims 1 to 8, comprising: When the heavy-loaded vehicle is traveling, the wheel hub motor transmits the required driving torque to the sun gear (10) through the motor shaft (9). The rotation of the sun gear (10) drives the planetary gear (11) to rotate. The rotation of the planetary gear (11) drives the ring gear (15) to rotate. The rotation of the ring gear (15) drives the planetary reducer housing (6) to rotate, thereby transmitting power to the wheel rim (5). The rotation of the wheel rim (5) drives the rotation of the brake drum (3). At this time, the brake drum (3) does not generate any braking torque, and the internal driving part and the braking part of the heavy-loaded vehicle electric wheel operate normally. When the heavy-loaded vehicle brakes, the brake wheel cylinder (17) outputs the braking thrust. The brake wheel cylinder (17) outputs the braking thrust to the brake shoe (4), so that the brake shoe (4) and the brake drum (3) are closely fitted, generating friction, forcing the rotation speed of the brake drum (3) to decrease, and finally causing the rotation speed of the wheel rim (5) to decrease, thereby achieving the purpose of decelerating the heavy-loaded vehicle.

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