wheel hub motor

Abstract

The application discloses a wheel hub motor which is convenient to assemble, comprising a main shaft, an end cover and a shell which are rotatably arranged on the main shaft through an end cover bearing and a shell bearing respectively, a stator which is fixedly arranged on the main shaft, a rotor which is rotatably arranged on the main shaft through a rotor bearing, a planet carrier, a sun gear, a gear ring which is fixedly arranged on the inner wall of the shell, and a planet wheel which is arranged on the planet carrier, wherein the rotor is rotatably arranged on the main shaft through two rotor bearings with the same size, the sun gear is in abutment with the rotor bearing, the rotor is provided with a check ring, one end of the stator is in abutment with the end cover bearing, the other end of the stator is in abutment with the rotor bearing, the main shaft is provided with a first step which cooperates with the stator to clamp the two rotor bearings, the main shaft is provided with a second step, one end of the planet carrier is in abutment with the shell bearing, and the other end of the planet carrier is in abutment with the second step. The wheel hub motor has the advantages that the wheel hub motor can be installed in place from one direction at one time, and the installation precision and the production efficiency are greatly improved.

Description

Technical Field

[0001] The present invention relates to a hub motor. Background Art

[0002] As a green means of transportation, power-assisted electric bicycles have seen significant growth internationally over the past decade, becoming a substantial industry. Power-assisted electric bicycle motors are typically categorized by their mounting location: front hub motors, rear hub motors, and mid-mount motors. Hub motors have a large market due to their simple structure and the ability to convert a bicycle into a power-assisted electric bicycle with minimal modification.

[0003] The installation method and working principle of the current power-assisted electric bicycle outer rotor gear hub motor, such as Figure 1 As shown, the stator aluminum core 16 is axially mounted on the step on the main shaft 1 and circumferentially secured against a flat key 12. The stator 5 is fixedly mounted on the stator aluminum core 16. Two rotor bearings 6 clamp the rotor 7 and are mounted on the step on the main shaft 1. The retaining ring 14 is then installed to complete the installation of the rotor 7. The sun gear 8 is fixed to the rotor 7. The planetary carrier 9 has a retaining ring 14 on its left side. The planetary carrier 9 is installed in the retaining ring position and circumferentially secured against a flat key 12. The housing 11 and end cover 2 are respectively mounted on the main shaft 1 via bearings. The bearings of the housing 11 and end cover 2 are pressed against the stator aluminum core 16 and planetary carrier 9 respectively, either through gaskets 4 or directly from their ends, securing the housing 11 and end cover 2 to each other. The ring gear 15 is fixed within the housing 11. The bearings used are typically deep groove ball bearings. During operation, the main shaft 1, stator aluminum core 16, stator 5, and planetary carrier 9 are stationary. The stator 5 and the rotor 7 interact to generate rotational power, which is input into the planetary reduction system through the sun gear 8. After deceleration, the ring gear 15 drives the housing 11 to output the power.

[0004] This assembly method has the following problems:

[0005] 1. The two rotor bearings 6 need to axially fix the rotor 7, so the bearing chamber (the cavity where the bearing is installed) needs to be separated. It will be difficult to complete the chip processing in one process. If the two processes are separated, the concentricity will be affected, and the assembly accuracy will be affected.

[0006] 2. Because the bearing chambers are separate, there is clearance between the bearings. From the perspective of motor installation theory, this should be a transition fit. If a transition fit is used, press-fitting is necessary, but deep groove ball bearings generally do not allow axial pressure. Furthermore, due to axial tolerances, press-fitting limits are difficult to control. Therefore, rotor bearing 6 and spindle 1 can only have a clearance fit. If spindle 1 deviates during machining, the clearance will be too large, affecting the operation of rotor 7. Therefore, this installation method can only improve the machining accuracy of spindle 1 to solve this problem, but it will increase costs.

[0007] 3. The ultimate axial fixation of rotor 7 relies on the step of main shaft 1 and circlip 14. The circlip 14 itself has tolerances, as does the circlip groove, which results in insufficient axial positioning accuracy. The usual practice is to widen the tolerances and then adjust the position using a 0.1mm thick adjustment shim.

[0008] 4. Planet carrier 9 needs to be fixed, and the circumferential rotation is prevented by a flat key 12. However, due to design space limitations, the length of this flat key 12 is typically only 10 mm. Since planet carrier 9 is the component subject to the greatest torque, this flat key 12 is prone to breakage. A common solution is to use a B-type key made of heat-treated 45-gauge steel, or even to use a non-standard flat key made of a different material.

[0009] 5. The end cover 2 and the housing 11 are both machined parts, so the distance tolerance between the two bearings on the end cover 2 and the housing 11 can be very well controlled. However, the planet carrier 9 is axially positioned by the retaining spring 14, and the same axial positioning accuracy problem as in question 3 also exists.

[0010] The above five problems result in increased motor assembly costs (installing retaining rings, replacing adjusting gaskets), unstable motor performance, high first-time assembly defect rate, and poor consistency. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a hub motor that is easy to assemble.

[0012] To solve the above technical problems, the present invention adopts the following technical solution: a hub motor includes a main shaft, an end cover and a housing rotatably mounted on the main shaft via an end cover bearing and a housing bearing, respectively, the end cover and the housing being connected, a cavity being formed between the end cover and the housing, the cavity containing a stator fixedly mounted on the main shaft, a rotor rotatably mounted on the main shaft via a rotor bearing, a planet carrier fixedly mounted on the main shaft, a sun gear fixedly mounted on the rotor, a ring gear fixedly mounted on the inner wall of the housing, a planet carrier provided with planet gears cooperating with the ring gear and the sun gear, the planet carrier being located between the sun gear and the housing bearing, the rotor being rotatably mounted on the main shaft via two rotor bearings of identical size and in contact with each other, the sun gear fixed to the rotor via screws and abutting against the rotor bearings, the rotor being provided with a retaining ring cooperating with the sun gear to clamp the two rotor bearings, one end of the stator abutting against the end cover bearing and the other end abutting against the rotor bearing, the main shaft being provided with a first step cooperating with the stator to clamp the two rotor bearings, the main shaft being provided with a second step, one end of the planet carrier abutting against the housing bearing and the other end abutting against the second step.

[0013] The stator is abutted against the end cover bearing via a first gasket.

[0014] The hub motor comprises a main shaft, an end cover and a shell which are rotatably arranged on the main shaft through an end cover bearing and a shell bearing respectively, the end cover and the shell are connected, a cavity is formed between the end cover and the shell, the cavity is internally provided with a stator fixedly arranged on the main shaft, a rotor rotatably arranged on the main shaft through a rotor bearing, a planet carrier fixedly arranged on the main shaft, a sun gear fixedly arranged on the rotor, a ring gear fixedly arranged on the inner wall of the shell, the planet carrier is provided with a planet gear matched with the ring gear and the sun gear, the planet carrier is located between the sun gear and the shell bearing, the rotor is rotatably arranged on the main shaft through two rotor bearings with the same size, the sun gear is fixed on the rotor through a screw and abuts against the rotor bearing, the rotor is provided with a stop ring matched with the sun gear to clamp the two rotor bearings, one end of the stator abuts against the shell bearing, the other end abuts against the rotor bearing, the main shaft is provided with a first step matched with the stator to clamp the two rotor bearings, the main shaft is provided with a second step, one end of the planet carrier abuts against the end cover bearing, the other end abuts against the second step.

[0015] The stator abuts against the shell bearing through a first gasket.

[0016] The two rotor bearings contact each other.

[0017] The planet carrier is arranged on the main shaft through a spline.

[0018] The beneficial effects of the present application are that, compared with the past installation mode, the axial positioning of each component no longer needs a circlip, and each component is provided with a step or an end face, the precision is ensured by mechanical processing, under the same processing condition, the precision of the assembly mode is easier to control than that of the mode using a circlip. Improving the precision is one of the ways to improve the stability of the product. At the same time, improving the precision no longer needs to adjust the gasket repeatedly, which reduces the assembly difficulty and the first assembly failure rate, and ensures the consistency of the motor without adjusting the gasket. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a structure diagram of the hub motor described in the background art;

[0020] Figure 2 It is a structure diagram of the first embodiment of the hub motor of the present application.

[0021] In the figure: 1, main shaft; 2, end cover; 3, end cover bearing; 4, gasket; 5, stator; 6, rotor bearing; 7, rotor; 8, sun gear; 9, planet carrier; 10, shell bearing; 11, shell; 12, key; 13, planet gear; 14, circlip; 15, ring gear; 16, stator aluminum core; 17, first step; 18, second step; 19, stop ring; 20, spline; 21, first gasket; 22, second gasket; DETAILED DESCRIPTION

[0022] The application will be described in greater detail with reference to the drawings.

[0023] Figure 2 As shown in the first embodiment of the hub motor of the present application, the hub motor comprises a main shaft 1, an end cover 2 and a housing 11 rotatably arranged on the main shaft 1 through an end cover bearing 3 and a housing bearing 10 respectively, the end cover 2 and the housing 11 are connected, and a cavity is formed between the end cover 2 and the housing 11, a stator 5 is fixedly arranged on the main shaft 1 in the cavity, a rotor 7 is rotatably arranged on the main shaft 1 through a rotor bearing 6, in actual production, the stator 5 is generally fixed on a stator aluminum core 16, and then the stator 5 is fixed on the main shaft 1 through the stator aluminum core 16 to realize the fixation of the stator 5 and the main shaft 1, a planet carrier 9 is fixedly arranged on the main shaft 1, a sun gear 8 is fixedly arranged on the rotor 7, a gear ring 15 is fixedly arranged on the inner wall of the housing 11, the planet carrier 9 is provided with a planet gear 13 matched with the gear ring 15 and the sun gear 8, the planet carrier 9 is located between the sun gear 8 and the housing bearing 10, the rotor 7 is rotatably arranged on the main shaft 1 through two rotor bearings 6 with the same size and in contact with each other, the sun gear 8 is fixed on the rotor 7 through a screw and abuts against the rotor bearing 6, the rotor 7 is provided with a blocking ring 19 matched with the sun gear 8 to clamp the two rotor bearings 6, one end of the stator 5 abuts against the end cover bearing 3, and the other end abuts against the rotor bearing 6, in actual production using the stator aluminum core 16, one end of the stator aluminum core 16 abuts against the end cover bearing 3, and the other end abuts against the rotor bearing 6. The main shaft 1 is provided with a first step 17 matched with the stator 5 (stator aluminum core 16) to clamp the two rotor bearings 6, of course, in actual production, the stator 5 (stator aluminum core 16) can directly abut against the rotor bearing 6 through a second gasket 22. The main shaft 1 is provided with a second step 18, which can be processed into a tool withdrawal groove in actual production. One end of the planet carrier 9 abuts against the housing bearing 10, and the other end abuts against the second step 18, that is, the planet carrier 9 is clamped and positioned by the housing bearing 10 and the second step 18. In actual production, a gasket can be used to abut between the planet carrier 9 and the housing bearing 10. In actual production, the stator 5 (stator aluminum core 16) can abut against the end cover bearing 3 through a first gasket 21. The planet carrier 9 is arranged on the main shaft 1 through a spline 20 to ensure the normal work of the planet carrier 9.

[0024] The advantages of the present application are: compared with the past installation mode, the axial positioning of each component no longer needs a circlip, and each is a self-step or end face, the precision is ensured by machining, and under the same machining conditions, the precision of this assembly mode is easier to control than using a circlip. Improving precision is one of the ways to improve product stability. At the same time, improving precision no longer requires adjusting shims to adjust repeatedly, which reduces assembly difficulty and reduces the first assembly failure rate, and the need for adjusting shims also ensures the consistency of the motor. Since the two rotor bearings 6 are connected, the bearing chamber for accommodating the rotor bearing 6 on the rotor 7 only needs to be machined once, which is convenient to machine and ensures the concentricity of the two rotor bearings 6.

[0025] The second embodiment of the hub motor of the present application is a hub motor, which comprises a main shaft 1, an end cover 2 and a housing 11 rotatably arranged on the main shaft 1 through an end cover bearing 3 and a housing bearing 10 respectively, the end cover 2 and the housing 11 are connected, and a cavity is formed between the end cover 2 and the housing 11, the cavity has a stator 5 fixedly arranged on the main shaft 1, in actual production, the stator 5 is fixed on the main shaft 1 through a stator aluminum core 16, a rotor 7 rotatably arranged on the main shaft 1 through a rotor bearing 6, a planet carrier 9 fixedly arranged on the main shaft 1, a sun gear 8 fixedly arranged on the rotor 7, a ring gear 15 fixedly arranged on the inner wall of the housing 11, the planet carrier 9 is provided with a planet gear 13 matched with the ring gear 15 and the sun gear 8, the planet carrier 9 is located between the sun gear 8 and the housing bearing 10, the rotor 7 is rotatably arranged on the main shaft 1 through two rotor bearings 6 with the same size and in contact with each other, the sun gear 8 is fixed on the rotor 7 through a screw and abuts against the rotor bearing 6, the rotor 7 is provided with a retainer ring 19 matched with the sun gear 8 to clamp the two rotor bearings 6, one end of the stator 5 (stator aluminum core 16) abuts against the housing bearing 10, and the other end abuts against the rotor bearing 6, the main shaft 1 is provided with a first step 17 matched with the stator 5 (stator aluminum core 16) to clamp the two rotor bearings 6, the main shaft 1 is provided with a second step 18, one end of the planet carrier 9 abuts against the end cover bearing 3, and the other end abuts against the second step 18. The stator 5 (stator aluminum core 16) abuts against the housing bearing 10 through a first gasket 21. The two rotor bearings 6 are in contact with each other. The planet carrier 9 is arranged on the main shaft 1 through a spline 20. That is, the second embodiment of the hub motor is different from the first embodiment only in that all the parts in the cavity are reversed in direction, that is, the installation direction is opposite. The advantages are the same as those of the first embodiment.

Claims

1. A hub motor comprising a main shaft, an end cap and a housing rotatably mounted on the main shaft via end cap bearings and housing bearings, respectively; the end cap and housing are connected to form a cavity between the end cap and the housing; the cavity contains a stator fixedly mounted on the main shaft, a rotor rotatably mounted on the main shaft via rotor bearings, a planet carrier fixedly mounted on the main shaft, a sun gear fixedly mounted on the rotor, and a ring gear fixedly mounted on the inner wall of the housing; planet gears are mounted on the planet carrier that cooperate with the ring gear and sun gear; the planet carrier is located between the sun gear and the housing bearings, and is characterized by: The rotor is rotatably arranged on the main shaft through two rotor bearings of the same size and in contact with each other. The sun gear is fixed to the rotor by screws and abuts against the rotor bearing. The rotor is provided with a retaining ring that cooperates with the sun gear to clamp the two rotor bearings. One end of the stator abuts against the end cover bearing, and the other end abuts against the rotor bearing. The main shaft is provided with a first step that cooperates with the stator to clamp the two rotor bearings. The main shaft is provided with a second step. One end of the planet carrier abuts against the housing bearing, and the other end abuts against the second step.

2. The hub motor according to claim 1, characterized in that: The stator is abutted against the end cover bearing via a first gasket.

3. The hub motor according to claim 1, characterized in that: The planet carrier is arranged on the main shaft via splines.

4. A hub motor comprising a main shaft, an end cap and a housing rotatably mounted on the main shaft via end cap bearings and housing bearings, respectively; the end cap and housing are connected to form a cavity between the end cap and the housing; the cavity contains a stator fixedly mounted on the main shaft, a rotor rotatably mounted on the main shaft via rotor bearings, a planet carrier fixedly mounted on the main shaft, a sun gear fixedly mounted on the rotor, a ring gear fixedly mounted on the inner wall of the housing, planet gears mounted on the planet carrier that cooperate with the ring gear and sun gear, and the planet carrier located between the sun gear and the housing bearings, characterized in that: The rotor is rotatably arranged on the main shaft through two rotor bearings of the same size. The sun gear is fixed to the rotor by screws and abuts against the rotor bearing. The rotor is provided with a retaining ring that cooperates with the sun gear to clamp the two rotor bearings. One end of the stator abuts against the housing bearing, and the other end abuts against the rotor bearing. The main shaft is provided with a first step that cooperates with the stator to clamp the two rotor bearings. The main shaft is provided with a second step. One end of the planet carrier abuts against the end cover bearing, and the other end abuts against the second step.

5. The hub motor according to claim 4, characterized in that: The stator is abutted against the housing bearing via a first gasket.

6. The hub motor according to claim 4, characterized in that: The planet carrier is arranged on the main shaft via splines.

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