A wheel-hub type inner rotor motor

Abstract

The application discloses a hub type inner rotor motor, which comprises a hub shell, an inner rotor motor, a motor shaft and a planetary gear set. The inner rotor motor drives the rotation of the planetary gear set, thereby driving the overall rotation of the hub shell. The inner rotor motor comprises an annular stator lamination located at the outer side and a rotor located at the center of the annular stator lamination. A motor shaft penetrates the middle part of the rotor gear of the rotor, and the rotation of the motor shaft synchronously drives the rotation of the rotor gear. The end part of the rotor gear extends to the middle part and forms an external tooth structure. The switching of the motor shaft by the clutch assembly realizes the switching of the driving mode of the motor shaft relative to the hub shell. Compared with the outer rotor motor, the outer rotor is replaced by the inner rotor in the limited space. The overall production cost of the motor can be reduced by reducing the material ratio of the magnetic steel. In the motor field with low torque requirement, the application has strong market.

Description

Technical Field

[0001] This invention belongs to the field of motor technology, specifically relating to a hub-type internal rotor motor. Background Technology

[0002] Hub motors, as an important component of the power and transmission systems of electric bicycles, generally use an external rotor motor hub. This type of external rotor motor is characterized by its space-saving and compact design, and it does not require a V-belt, making it suitable for installation in the impeller.

[0003] Due to the design structure of the external rotor motor, which has a circular rotor on the outside and a stator with excitation coils on the inside, this external rotor motor structure can be applied to low-speed, high-torque scenarios. For motors of the same size, the rotor diameter of the inner rotor is not as large as that of the outer rotor, and the torque is generally proportional to the rotor diameter. Moreover, the outer rotor can generate large torque at low speeds, and its large moment of inertia enables stable operation.

[0004] However, while the annular magnet structure on the outer circumference of the outer rotor can generate greater torque, it requires a larger amount of magnets, which greatly increases the design cost. Furthermore, since the magnets of the outer rotor are located on the outside, in some spaces with limited space, installing an outer rotor motor will compress the positions of other components, limiting the increase in output torque and thus affecting the overall power.

[0005] Chinese patent CN201420400308.0 discloses an external rotor motor stator lamination, an external rotor motor stator, a motor, and a fan. In this device, the stator lamination adopts a single-slot winding design to avoid common-slot design, which greatly helps the winding process and automation. The design center of a pair of first and second single slots has independent first and second teeth, which can increase the magnetic field loop, improve the magnetic field uniformity, reduce leakage magnetic loss, increase the effective magnetic induction area, increase the magnetic flux, improve the output capacity, and improve the motor energy efficiency. However, while increasing the magnetic flux, the outer diameter of the magnet stator located on the outside must increase, which will affect the size limitation. At the same time, increasing the size of the magnet stator also greatly increases the equipment cost. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a hub-type internal rotor motor, which solves the above-mentioned technical problems existing in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A hub-type internal rotor motor includes a hub housing, an internal rotor motor, a motor shaft, and a planetary gear set. The internal rotor motor and the planetary gear set are located inside the hub housing. The internal rotor motor drives the rotation of the planetary gear set, thereby driving the entire hub housing to rotate.

[0009] The internal rotor motor includes an annular stator lamination located on the outer side and a rotor located at the center of the annular stator lamination. The rotor consists of a rotor gear and magnetic steel plates. The magnetic steel plates are evenly and fixedly distributed on the outer side of the rotor gear. At the same time, a motor shaft passes through the middle of the rotor gear and drives the rotor gear to rotate synchronously through the rotation of the motor shaft. Meanwhile, the end of the rotor gear extends towards the middle and forms an external tooth structure.

[0010] The planetary gear set includes a main gear, a steel gear, and a gear shaft. The external teeth of the rotor gear synchronously drive the main gear, which meshes with it, to rotate. The gear shaft is concentrically located at the center of the main gear and rotates synchronously with it. The front end of the gear shaft meshes with the steel gear and drives the steel gear to rotate synchronously. At the same time, the steel gear is fixed to the end cap, so that the end cap and the hub shell form a whole, and the rotation of the steel gear synchronously drives the entire hub shell to rotate.

[0011] Furthermore, a clutch assembly is provided on the outer side of the end cap of the car, and the clutch assembly is synchronously sleeved on the end of the motor shaft; by switching the motor shaft through the clutch assembly, the driving mode of the motor shaft relative to the hub housing is switched.

[0012] Furthermore, the outer teeth of the rotor gear are concentrically arranged with the outer ring and are integrally formed. At the same time, slots are equally spaced around the central axis on the outer periphery of the outer ring, and the magnet is embedded in the slot.

[0013] Furthermore, the end of the magnetic steel sheet extends outward 1-3mm beyond the end face of the slot.

[0014] Furthermore, a Hall element sensor is positioned between two adjacent sets of magnets.

[0015] Furthermore, the main gear is made of nylon.

[0016] Furthermore, the external teeth of the main gear and the rotor gear mesh with each other in a helical manner.

[0017] Furthermore, the gear shaft is concentrically positioned at the center of the main gear via a first one-way bearing. When the inner rotor motor drives the gear shaft on the main gear, the rotor gear drives the gear shaft in one direction. When the motor shaft is manually driven, the rotation direction of the motor shaft changes, and the rotor gear on the motor shaft directly acts on the card end cover and transmits synchronously.

[0018] Furthermore, the connection between the rotor gear and the clutch assembly is made using a second one-way bearing.

[0019] The beneficial effects of this invention are:

[0020] 1. In a limited space, this device uses an internal rotor motor to drive the hub to rotate as a whole. The motor shaft is a through-shaft type with both ends, which achieves uniform force on both ends compared to the half-shaft output method. At the same time, it uses a reduction gear instead of a planetary reduction method. Its bias setting can improve its overall service life and stability, which is conducive to improving the output torque.

[0021] 2. The first one-way bearing on the main gear of this device and the second one-way bearing on the clutch assembly work together to enable free switching between electric drive and manual drive, ensuring that the two drive modes do not affect each other and providing high operability.

[0022] 3. The main gear used in this device is a nylon gear. When the nylon gear meshes with the rotor gear, it can improve its wear resistance and reduce the generation of mechanical noise. At the same time, the helical gear mounting method of the main gear achieves a compact structure, which can save limited space when producing the same transmission ratio, improve its overall meshing performance, increase its load-bearing capacity, and ensure full contact and force distribution between the teeth during meshing, thus extending the service life and fatigue resistance of the gear.

[0023] 4. The Hall element sensor on this device is installed in the gap between two adjacent sets of magnet plates, which can be easily installed, disassembled and replaced, reducing the impact of its installation on the external stator and affecting the overall installation. Moreover, the installation is not affected by the number of stator slots. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the overall internal structure of an embodiment of the present invention;

[0026] Figure 2 This is a cross-sectional structural schematic diagram of an embodiment of the present invention;

[0027] Figure 3This is a schematic diagram of the internal rotor motor portion of an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the rotor gear structure according to an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the planetary gear set structure according to an embodiment of the present invention;

[0030] Figure 6 This is a schematic diagram of the overall external hub structure according to an embodiment of the present invention. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] like Figure 1 , Figure 2 As shown, this embodiment of the invention provides a hub-type internal rotor motor, including a hub housing 1, an internal rotor motor 2, a motor shaft 3, a planetary gear set 4, and a clutch assembly 5. The internal rotor motor 2 and the planetary gear set 4 are located inside the hub housing 1 and are entirely enclosed within it by a clutch end cap 11. The internal rotor motor 2 drives the planetary gear set 4 to rotate, thereby causing the entire hub housing 1 to rotate. The clutch assembly 5 is located on the outer side of the clutch end cap 11 and is synchronously fitted onto the protruding end of the motor shaft 3. By switching the motor shaft 3 using the clutch assembly 5, the driving mode of the motor shaft 3 relative to the hub housing 1 is switched, thereby changing whether the hub housing 1 is driven by a motor or manually.

[0033] like Figure 3 , Figure 4 As shown, the inner rotor motor 2 includes an annular stator lamination 21 located on the outer side and a rotor 22 located at the center of the annular stator lamination 21. The rotor 22 is composed of rotor gears 221 and magnets 222. The outer teeth of the rotor gears 221 are concentrically arranged with the outer ring and adopt an integral molding structure. At the same time, slots 201 are equally spaced around the central axis on the outer circumference of the outer ring. The magnets 222 are embedded in the slots 201. At this time, the end of the magnets 222 extends outward 1-3mm from the end face of the slots 201. This arrangement will create a gap between two adjacent groups of magnets 222. Hall element sensors 202 are embedded on two of the groups of magnets 222.

[0034] In general, Hall effect sensors in internal rotor motors are placed in the lamination slots on the outer side. This design provides stable placement and prevents them from falling off. However, if the lamination slots are too dense, it can affect the installation of the Hall effect sensor (because the windings in adjacent stator slots are too dense, which can compress the Hall effect sensor's position). In this application, the Hall effect sensor 202 is placed inside the magnet plate 222, rather than in the outer stator slot. This arrangement is unaffected by the number of slots (it is not easy to fall off in densely packed areas), and even if the number of slots is relatively dense, it will not be affected. The specific installation position of the Hall effect sensor 202 can be customized as needed, and it is easy to replace. In contrast, the traditional Hall effect sensor position is entangled with the windings on the annular stator lamination 21, requiring the entire sensor to be replaced for disassembly and maintenance, which is time-consuming and laborious. This design does not affect installation or replacement.

[0035] Meanwhile, the motor shaft 3 passes through the middle of the rotor gear 221, and the rotation of the motor shaft 3 synchronously drives the rotation of the rotor gear 221. The end of the rotor gear 221 extends towards the middle and forms an external tooth structure.

[0036] like Figure 5 As shown, the planetary gear set 4 includes a main gear 41 (the main gear 41 is a nylon gear, which reduces gear noise during meshing and improves its overall wear resistance), a steel gear 42, and a gear shaft 43. The external teeth of the rotor gear 221 synchronously drive the main gear 41, which meshes with it, to rotate (helical teeth can be used for meshing, which has a compact structure, saves limited space when producing the same transmission ratio, and improves its overall meshing performance and load-bearing capacity. Furthermore, the teeth fully contact and distribute force during meshing, extending the tooth length). The gear shaft 43 is concentrically located in the middle of the main gear 41 and rotates synchronously with the main gear 41. The front end of the gear shaft 43 meshes with the steel gear 42 and drives the steel gear 42 to rotate synchronously (they can mesh with each other in a helical gear manner). The steel gear 42 is fixed to the end cap 11 (fixed by bolts on the back, which improves the firmness and facilitates disassembly, maintenance and installation), so that the end cap 11 and the hub shell 1 form a whole, and the hub shell 1 rotates synchronously with the rotation of the steel gear 42.

[0037] In use, the gear shaft 43 is concentrically positioned at the center of the main gear 41 via the first one-way bearing 401. When the inner rotor motor 2 is driven, the rotor gear 221 drives the gear shaft 43 on the main gear 41 to rotate in one direction (at this time, the rotation of the main gear 41 will synchronously drive the rotation of the gear shaft 43, thereby causing the steel gear 42 meshing with the gear shaft 43 to rotate). The second one-way bearing 111 at the connection between the rotor gear 221 and the clutch assembly 5 is a non-transmission connection, so the rotation of the rotor gear 221 does not drive the transmission of the clutch end cover 11 connected to it. When the clutch assembly 5 is used to change the transmission method, i.e., when the motor shaft 3 is driven by a human foot pedal, the rotation direction of the motor shaft 3 changes. The rotor gear 221 on the motor shaft 3 directly acts on the clutch end cover 11 via the second one-way bearing 111 and achieves synchronous transmission. At this time, after the rotor gear 221 drives the main gear 41 to rotate, since the first one-way bearing 401 is a one-way transmission, it will not drive the steel gear 42 to rotate again.

[0038] like Figure 6 As shown in the diagram, this application replaces the external rotor with an internal rotor in a limited space, which can reduce the overall production cost of the motor by reducing the proportion of magnets used. At the same time, the use of reduction gears instead of planetary reduction gears and the setting of its bias mode can improve its overall service life. It has a strong market in the field of motors with low torque requirements.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A hub-type internal rotor motor, comprising a hub housing (1), an internal rotor motor (2), a motor shaft (3), and a planetary gear set (4), characterized in that, The inner rotor motor (2) and planetary gear set (4) are located inside the hub housing (1). At the same time, the inner rotor motor (2) drives the rotation of the planetary gear set (4), thereby driving the overall rotation of the hub housing (1). The inner rotor motor (2) includes an annular stator lamination (21) located on the outer side and a rotor (22) located at the center of the annular stator lamination (21). The rotor (22) is composed of a rotor gear (221) and magnetic steel plates (222). The magnetic steel plates (222) are evenly and fixedly distributed on the outer side of the rotor gear (221). At the same time, a motor shaft (3) passes through the middle of the rotor gear (221), and the rotation of the rotor gear (221) is synchronously driven by the rotation of the motor shaft (3). Meanwhile, the end of the rotor gear (221) extends towards the middle and forms an external tooth structure. The planetary gear set (4) includes a main gear (41), a steel gear (42), and a gear shaft (43). The external teeth of the rotor gear (221) synchronously drive the main gear (41) that meshes with it to rotate. The gear shaft (43) is concentrically located at the middle position of the main gear (41) and rotates synchronously with the main gear (41). The front end of the gear shaft (43) meshes with the steel gear (42) and drives the steel gear (42) to rotate synchronously. At the same time, the steel gear (42) is fixed to the end cap (11), so that the end cap (11) and the hub shell (1) form a whole, and the hub shell (1) rotates synchronously with the rotation of the steel gear (42).

2. The hub-type internal rotor motor according to claim 1, characterized in that, A clutch assembly (5) is provided on the outside of the end cap (11) of the car. The clutch assembly (5) is synchronously sleeved on the end of the motor shaft (3) that extends out. By switching the motor shaft (3) through the clutch assembly (5), the driving mode of the motor shaft (3) relative to the hub housing (1) is switched.

3. The hub-type internal rotor motor according to claim 1, characterized in that, The outer teeth of the rotor gear (221) are concentrically arranged with the outer ring and are integrally formed. At the same time, slots (201) are equally spaced around the central axis on the outer periphery of the outer ring, and the magnet (222) is embedded in the slot (201).

4. The hub-type internal rotor motor according to claim 3, characterized in that, The end of the magnetic steel sheet (222) extends outward 1-3mm from the end face of the slot (201).

5. The hub-type internal rotor motor according to claim 4, characterized in that, A Hall element sensor (202) is disposed between two adjacent sets of magnets (222).

6. The hub-type internal rotor motor according to claim 1, characterized in that, The main gear (41) is made of nylon.

7. The hub-type internal rotor motor according to claim 6, characterized in that, The external teeth of the main gear (41) and the rotor gear (221) mesh with each other in a helical manner.

8. The hub-type internal rotor motor according to claim 1, characterized in that, The gear shaft (43) is concentrically positioned at the center of the main gear (41) via the first one-way bearing (401). When the inner rotor motor (2) drives the gear shaft (43) on the main gear (41) to transmit in one direction via the rotor gear (221). When the motor shaft (3) is manually driven, the rotation direction of the motor shaft (3) changes, and the rotor gear (221) on the motor shaft (3) directly acts on the card end cover (11) and transmits synchronously.

9. The hub-type internal rotor motor according to claim 8, characterized in that, The rotor gear (221) and the clutch assembly (5) are connected by a second one-way bearing (111).

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