A wheel hub motor and electric vehicle with an external resolver

Abstract

A kind of wheel hub motor of external resolver and electric vehicle, including support shaft, stator being arranged on support shaft and wheel hub, wheel hub includes two end covers being oppositely arranged, and the outer side of one end cover is provided with accommodating groove around support shaft, resolver stator and resolver rotor are arranged in accommodating groove, resolver stator is sleeved on support shaft and is fixed with support shaft, resolver rotor is sleeved on the outer side of resolver stator and is connected with accommodating groove, gap is formed between the inner wall of resolver rotor and the outer wall of resolver stator, resolver rotor rotates synchronously with accommodating groove;The mouth of accommodating groove is provided with annular sealing element.The utility model has the following advantages compared with prior art: the resolver of the present scheme is arranged in the end cover of wheel hub motor, which facilitates the maintenance, detection and repair of resolver, and the repair and replacement of resolver do not need to damage the sealing structure of end cover of wheel hub motor, which helps to prolong the service life of wheel hub motor;At the same time, the assembly difficulty of resolver is reduced.

Description

Technical Field

[0001] This utility model relates to hub motors, specifically to hub motors with external rotary transformers and electric vehicles. Background Technology

[0002] With the increasing popularity of electric bicycles and electric motorcycles in the market, the demands on the performance and functionality of electric vehicles are also rising. Most existing two-wheeled electric vehicle hub motors use Hall effect sensors to detect changes in the magnetic field, converting the magnetic signal into an electrical signal and transmitting it to the controller. When the motor uses Hall elements to collect rotor information, the poor temperature characteristics of the Hall elements cause high internal temperatures during heavy motor operation, easily damaging the Hall elements and affecting their accuracy and sensitivity. Damaged Hall element output signals further affect the controller's control accuracy, impacting motor operating characteristics and reducing overall riding comfort. High temperatures can even directly cause irreparable damage to the Hall elements, affecting the motor's lifespan. Furthermore, when using high-power, high-speed motors, the continuous increase in load current causes the induced electromotive force generated in the motor's internal winding coils to significantly affect the Hall elements' acquisition of permanent magnet rotor position information, directly leading to rotor position distortion. This prevents the controller from accurately controlling motor commutation, causing the motor to stop working directly. Finally, the Hall elements are installed in the Hall slots of the stator core inside the motor, making them susceptible to mechanical damage during installation, affecting their lifespan.

[0003] Modern hub motors are gradually adopting encoders instead of Hall elements to collect rotor information. However, the operating environment of two-wheeled electric vehicles is subject to many uncertainties, such as bumpy road conditions and long-distance travel, which can easily damage the encoder. Compared with rotary transformers, encoders are more adaptable to harsh working environments.

[0004] For example, the publication number CN210898837U, entitled "A Hub Motor with a Rotary Transformer," includes a motor hub (1). Its features include: a motor side cover (2) fixedly installed on the left side of the motor hub (1), a disc brake cover (3) fixedly installed on the right side of the motor hub (1), a motor shaft (4) inserted at the axis between the motor side cover (2) and the disc brake cover (3), a motor stator bracket (5) fixedly installed in the middle of the motor shaft (4), a motor stator winding (6) fixedly connected to the outer surface of the motor stator bracket (5), a permanent magnet fixedly installed on the inner wall of the motor hub (1), and an electromagnetic sensing mechanism (8) between the motor stator bracket (5) and the disc brake cover (3). Although the above scheme discloses a technical solution for setting a rotary transformer on a hub motor, this scheme places the rotary transformer inside the hub, making assembly difficult and inconvenient for future maintenance, inspection, and repair of the rotary transformer. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hub motor and electric vehicle with an external rotary transformer.

[0006] The main technical solution of the hub motor with external rotary transformer provided by this utility model is as follows: it includes a support shaft, a stator and a hub mounted on the support shaft. The hub includes two end caps arranged opposite each other, and a cavity is formed inside the hub. The stator is located inside the cavity. The support shaft passes through the two end caps. One of the end caps has a receiving groove around the support shaft on its outer side. A rotary transformer stator and a rotary transformer rotor are provided in the receiving groove. The rotary transformer stator is sleeved on the support shaft and fixed to the support shaft. The rotary transformer rotor is sleeved on the outside of the rotary transformer stator and connected to the receiving groove. A gap is formed between the inner wall of the rotating rotor and the outer wall of the rotary transformer stator. The rotary transformer rotor rotates synchronously with the receiving groove. An annular seal is provided at the opening of the receiving groove.

[0007] The hub motor with an external rotary transformer provided by this utility model also adopts the following auxiliary technical solutions:

[0008] Preferably, the annular seal includes a bushing fixedly fitted on the support shaft, and a rotary seal disposed between the outer wall of the bushing and the inner wall of the receiving groove.

[0009] Preferably, the bushing is provided with a plug-in terminal, one end of which is electrically connected to the resolver stator, and the other end of which is exposed on the outside of the bushing.

[0010] Preferably, the bushing is provided with a wire passage hole and also includes a resolver connecting wire, which passes through the wire passage hole, with one end connected to the resolver stator and the other end exposed.

[0011] Preferably, the outer wall of the support shaft is provided with a wire guide groove, and the bushing is fitted on the part opposite to the wire guide groove. The length of the wire guide groove is greater than the axial length of the bushing. It also includes a resolver connecting wire, which passes through the wire guide groove, with one end connected to the resolver stator and the other end exposed.

[0012] Preferably, the annular seal is an oil seal.

[0013] Preferably, the support shaft is provided with a control line passage channel that connects to the inner cavity of the hub, and the support shaft is also provided with a resolver passage channel. One end of the resolver passage channel is connected to the receiving groove, and the other end is connected to the control line passage channel. It also includes a resolver connecting wire, one end of which is connected to the resolver stator. The resolver connecting wire passes through the resolver passage channel and the control line passage channel in sequence, and the other end is exposed.

[0014] Preferably, one end cap has a receiving groove on its outer side and the other end cap has a brake assembly groove on its outer side.

[0015] Preferably, the outer circular wall of the rotary seal and the inner wall of the receiving groove are fitted with any one or more combinations of interference fit, snap fit, and adhesive fixation; the inner circular wall of the rotary seal and the bushing are rotatably fitted.

[0016] Preferably, the rotary seal is an oil seal.

[0017] Preferably, the receiving groove includes a first receiving groove and a second receiving groove that are connected to each other, the resolver stator and the resolver rotor are located in the first receiving groove, the annular seal is located in the second receiving groove, the inner diameter of the first receiving groove is smaller than the inner diameter of the second receiving groove, and a step is formed between the first receiving groove and the second receiving groove.

[0018] The main technical solution of the electric vehicle provided by this utility model is as follows: it includes a frame, a hub motor mounted on the frame, a tire mounted on the hub motor, and a battery and controller mounted on the frame. The hub motor includes a support shaft, a stator mounted on the support shaft, and a hub. The hub includes two end caps arranged opposite each other, and a cavity is formed inside the hub, with the stator located inside the cavity. The support shaft passes through the two end caps, and the outer side of one end cap is provided with a receiving groove around the support shaft. A resolver stator and a resolver rotor are provided in the receiving groove. The resolver stator is sleeved on the support shaft and fixed to the support shaft. The resolver rotor is sleeved on the outside of the resolver stator and connected to the receiving groove. A gap is formed between the inner wall of the rotating rotor and the outer wall of the resolver stator. The resolver rotor rotates synchronously with the receiving groove. An annular seal is provided at the opening of the receiving groove.

[0019] Compared with the prior art, the hub motor and electric vehicle with an external rotary transformer provided by this utility model have the following advantages: This solution places the rotary transformer outside the end cover of the hub motor, which facilitates the maintenance, inspection and repair of the rotary transformer. Moreover, the maintenance and replacement of the rotary transformer does not require damaging the sealing structure of the end cover of the hub motor, which helps to extend the service life of the hub motor. At the same time, it reduces the assembly difficulty of the rotary transformer and improves the assembly efficiency. Attached Figure Description

[0020] Figure 1 This is a cross-sectional view of a hub motor according to Embodiment 1 of this utility model.

[0021] Figure 2 for Figure 1 A magnified view of A in the middle.

[0022] Figure 3 This is a structural diagram of the bushing and plug-in terminal after assembly in Embodiment 1 of this utility model.

[0023] Figure 4 This is a structural diagram of a hub motor according to Embodiment 1 of this utility model.

[0024] Figure 5This is a structural diagram of the hub motor after removing the annular seal in Embodiment 1 of this utility model.

[0025] Figure 6 This is a cross-sectional view of the hub motor in Embodiment 2 of this utility model.

[0026] Figure 7 for Figure 6 A magnified view of B in the middle.

[0027] Figure 8 This is a cross-sectional view of the hub motor in Embodiment 3 of this utility model.

[0028] Figure 9 for Figure 8 A magnified view of C.

[0029] Figure 10 This is a cross-sectional view of the hub motor of Embodiment 4 of this utility model.

[0030] Figure 11 for Figure 10 A magnified view of D. Detailed Implementation

[0031] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] The working principle of a rotary transformer: A rotary transformer is an electromagnetic sensor, a small AC motor used to measure the angular displacement and angular velocity of a rotating object's shaft. It consists of a stator and a rotor. The stator winding, as the primary side of the transformer, receives the excitation voltage, with excitation frequencies typically at 400, 3000, and 500 Hz. The rotor winding, as the secondary side of the transformer, receives the induced voltage through electromagnetic coupling. The working principle of a rotary transformer is the same as that of a conventional transformer. A sinusoidal alternating current is applied to the excitation winding, generating an alternating magnetic field. The magnetic circuit formed by the rotor core transmits this alternating magnetic field to the sine and cosine windings, generating an induced electromotive force (EMF). Because the rotor core of a rotary transformer is not circular, the air gap between the sine / cosine windings and the rotor core differs, resulting in different magnitudes of the induced EMF in the sine / cosine windings. Therefore, during operation, the amplitude of the induced EMF in the sine / cosine windings changes with the rotation of the rotary transformer rotor.

[0033] Example 1

[0034] See Figures 1 to 5According to the embodiment of the hub motor with external rotary transformer provided by the utility model, it includes a support shaft 3, a stator (not shown in the figure) disposed on the support shaft 3, and a hub. The hub includes two end caps 1 disposed opposite to each other, and a cavity 2 is formed inside the hub. The stator is located in the cavity 2. The stator includes a stator bracket fixed on the support shaft 3 and a stator core disposed on the outer periphery of the stator bracket. The stator structure is a relatively mature technology in the prior art, and will not be described in detail here. The support shaft 3 passes through the two end caps 1. The outer side of one of the end caps 1 is provided with a receiving groove 11 around the support shaft 3. A resolver stator 41 and a resolver rotor 42 are disposed in the receiving groove 11. The resolver stator 41 is sleeved on the support shaft 3 and fixed to the support shaft 3. The resolver rotor 42 is sleeved on the outside of the resolver stator 41 and connected to the receiving groove 11. A gap is formed between the inner wall of the rotating rotor and the outer wall of the resolver stator 41. The resolver rotor 42 rotates synchronously with the receiving groove 11. An annular seal is provided at the opening of the receiving groove 11. This solution places the rotary transformer outside the end cover 1 of the hub motor, which facilitates the maintenance, inspection and repair of the rotary transformer. Moreover, the maintenance and replacement of the rotary transformer does not require damaging the sealing structure of the end cover 1 of the hub motor, which helps to extend the service life of the hub motor. At the same time, it reduces the assembly difficulty of the rotary transformer and improves the assembly efficiency.

[0035] See Figure 2 and Figure 4 According to the above-described embodiments of the utility model, the annular seal includes a bushing 5 fixedly fitted on the support shaft 3, and a rotary seal 6 disposed between the outer side wall of the bushing 5 and the inner side wall of the receiving groove 11. The annular seal adopts the above-described structure of an inner bushing 5 and an outer rotary seal 6 in rotational engagement, which is simple in structure, has fewer parts, is easy to assemble, and has high reliability. The bushing 5 and the support shaft 3 can be fixed by interference fit, snap fit, or locking components such as screws; the design of the bushing 5 reduces the radial thickness of the rotary seal 6, making the seal more reliable and less prone to deformation; the bushing 5 can also serve as a passage for the rotary connecting wire to the outside, which, compared with the prior art design of independently drilling a rotary connecting wire passage hole 51 on the support shaft 3, results in lower production costs, easier assembly, and does not damage the mechanical strength of the support shaft 3.

[0036] See Figures 1 to 4According to the above-described embodiment of the utility model, the bushing 5 is provided with a plug-in terminal 7. One end of the plug-in terminal 7 is electrically connected to the resolver stator 41, and the other end of the plug-in terminal 7 is exposed on the outside of the bushing 5. Using the plug-in terminal 7 to achieve electrical connection between the resolver stator 41 and the outside makes connection with the electric vehicle controller more convenient, eliminates the wiring process, and ensures high reliability of the wiring connection. The bushing 5 is provided with terminal holes, and the plug-in terminal 7 is embedded in the terminal holes. The plug-in terminal 7 is fixed to the bushing 5 in this way, and its outer surface is flush with the outer surface of the bushing 5, making it less susceptible to damage from contact. Both ends of the plug-in terminal 7 are plug-in interfaces. The plug-in interface located inside the bushing 5 is plugged into and cooperates with the magnetic encoder. The resolver stator 41 and the plug-in terminal 7 also adopt a terminal-type connection, making assembly more convenient and ensuring high reliability. A combined component consisting of a resolver stator 41, bushing 5, and plug-in terminal 7 can be assembled and then installed on the hub motor, greatly improving the assembly effect of the product.

[0037] See Figure 1 According to the above-described embodiment of the utility model, one end cover 1 has a receiving groove 11 on its outer side, and the other end cover 1 has a brake assembly groove on its outer side. This structure allows the rotary transformer and the brake assembly to be located on opposite sides of the hub motor, facilitating assembly and preventing interference between their wiring harnesses.

[0038] See Figure 2 and Figure 4 According to the above-described embodiments of the utility model, the outer circular wall of the rotary seal 6 and the inner wall of the receiving groove 11 are fitted with any one or more combinations of interference fit, snap fit, and adhesive fixation; the inner circular wall of the rotary seal 6 and the bushing 5 are rotatably fitted. In this embodiment, the outer circular wall of the rotary seal 6 and the inner wall of the receiving groove 11 are fitted with interference fit and adhesive fixation. This structure helps to increase the height of the movable gap of the rotary seal 6, minimizing the possibility of water entering the receiving groove 11 through the movable gap. The rotary seal 6 is an oil seal, which has good sealing effect and low component cost.

[0039] See Figure 2According to the above-described embodiment of the utility model, the receiving groove 11 includes a first receiving groove 111 and a second receiving groove 112 that are connected to each other. The resolver stator 41 and the resolver rotor 42 are located in the first receiving groove 111, and the annular seal is located in the second receiving groove 112. The inner diameter of the first receiving groove 111 is smaller than the inner diameter of the second receiving groove 112, and a step is formed between the first receiving groove 111 and the second receiving groove 112. The resolver rotor 42 and the first receiving groove 111 can be fixed by any one or more combinations of snap-fit, adhesive, and interference fit to ensure the reliability of the resolver rotor 42's fixation. The step is an annular step, and the rotating seal 6 abuts against the annular step on one side edge facing the receiving groove 11. This structure facilitates the installation of the rotating seal 6 and avoids sealing failure caused by improper installation or over-insertion of the rotating seal 6 into the receiving groove 11.

[0040] According to the embodiment of the electric vehicle provided by the utility model, it includes a frame, a hub motor mounted on the frame, a tire mounted on the hub motor, and a battery and controller mounted on the frame. The frame, battery, and controller are all relatively mature technologies in the prior art, and will not be described in detail here. In this embodiment, the hub motor is the hub motor with an external rotary transformer as described in the previous embodiment, and the rotary transformer stator 41 is connected to the controller. This solution places the rotary transformer outside the end cover 1 of the hub motor, which facilitates the maintenance, inspection, and repair of the rotary transformer. Furthermore, the repair and replacement of the rotary transformer does not require damaging the sealing structure of the end cover 1 of the hub motor, which helps to extend the service life of the hub motor; at the same time, it reduces the assembly difficulty of the rotary transformer and improves assembly efficiency.

[0041] Example 2

[0042] See Figure 6 and Figure 7 This embodiment is structurally similar to Embodiment 1 above, except that the wiring method between the resolver stator 41 and the external components differs. In this embodiment, the bushing 5 is provided with a wire-passing hole 51, and also includes a resolver connecting wire (not shown in the figure). The resolver connecting wire passes through the wire-passing hole 51, with one end connected to the resolver stator 41 and the other end exposed. Directly opening the wire-passing hole 51 for the resolver connecting wire on the bushing 5 is more convenient and cost-effective than drilling a dedicated channel for the resolver connecting wire on the support shaft 3 in the prior art. Furthermore, the bushing 5 is closest to the resolver stator 41, making wiring very convenient.

[0043] Example 3

[0044] See Figure 8 and Figure 9This embodiment is structurally similar to Embodiment 1 above, except that the wiring method between the resolver stator 41 and the outside is different. In this embodiment, the outer wall of the support shaft 3 is provided with a wire-passing groove 31, and the bushing 5 is fitted onto the part opposite to the wire-passing groove 31. The length of the wire-passing groove 31 is greater than the axial length of the bushing 5. It also includes a resolver connecting wire, which passes through the wire-passing groove 31, with one end connected to the resolver stator 41 and the other end exposed. By opening the wire-passing groove 31 on the support shaft 3, the resolver stator 41 connecting wire is led out from the receiving groove 11, and the wire-passing groove 31 is opposite to the bushing 5. Except for the two ends of the connecting wire protruding from the wire-passing groove 31, the other part of the wire-passing groove 31 is covered by the bushing 5. Compared with the prior art of drilling a special channel on the support shaft 3 for the resolver stator 41 connecting wire, opening the wire-passing groove 31 is easier to process and lower in cost.

[0045] Example 4

[0046] See Figure 10 and Figure 11 This embodiment is structurally similar to Embodiment 1 above, except that the wiring method between the resolver stator 41 and the outside is different. In this embodiment, the support shaft 3 is provided with a control line passage 32 that connects to the inner cavity of the hub, and the support shaft 3 is also provided with a resolver passage 33. One end of the resolver passage 33 is connected to the receiving groove 11, and the other end is connected to the control line passage 32. It also includes a resolver connecting wire, one end of which is connected to the resolver stator 41. The resolver connecting wire passes through the resolver passage 33 and the control line passage 32 in sequence, and the other end is exposed. In this embodiment, the resolver passage 33 is connected to the control line passage 32, which greatly shortens the length of the resolver passage 33. It only needs to be drilled to the length of the receiving groove 11 to the control line passage 32. Compared with the prior art of drilling a special channel for the resolver connecting wire on the support shaft 3, it is easier to process and has a lower cost.

[0047] Example 5

[0048] This embodiment is structurally similar to Embodiment 4 above, except for the annular seal structure, which is an oil seal in this embodiment. Compared with Embodiments 1 to 3 above, since the resolver connecting line does not pass through the control line passage and resolver passage on the support shaft 3 to communicate with the outside, it does not need to pass through the bushing 5. Only an oil seal is used to dynamically seal the receiving groove 11, which simplifies the product structure and reduces production costs.

[0049] The technical solution provided by this utility model has been described in detail above. Specific examples have been used to illustrate the principle and implementation of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. The terms "front," "back," "left," "right," "positive," and "negative" in this solution are all terms used to describe things clearly from a certain perspective. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A hub motor with an external rotary transformer, comprising a support shaft, a stator mounted on the support shaft, and a hub, the hub comprising two oppositely disposed end caps, a cavity formed within the hub, and the stator located within the cavity; the support shaft passing through the two end caps, characterized in that, One of the end caps has a receiving groove on its outer side around the support shaft. The receiving groove contains a resolver stator and a resolver rotor. The resolver stator is sleeved on the support shaft and fixed to the support shaft. The resolver rotor is sleeved on the outside of the resolver stator and connected to the receiving groove. A gap is formed between the inner wall of the rotating rotor and the outer wall of the resolver stator. The resolver rotor rotates synchronously with the receiving groove. The opening of the receiving groove is provided with an annular seal.

2. The hub motor with an external rotary transformer according to claim 1, characterized in that, The annular seal includes a bushing fixedly fitted on the support shaft and a rotary seal disposed between the outer wall of the bushing and the inner wall of the receiving groove.

3. The hub motor with an external rotary transformer according to claim 2, characterized in that, The bushing is equipped with a plug-in terminal. One end of the plug-in terminal is electrically connected to the resolver stator, and the other end of the plug-in terminal is exposed on the outside of the bushing.

4. The hub motor with an external rotary transformer according to claim 2, characterized in that, The bushing is provided with a wire passage hole and also includes a resolver connecting wire. The resolver connecting wire passes through the wire passage hole, with one end connected to the resolver stator and the other end exposed.

5. The hub motor with an external rotary transformer according to claim 2, characterized in that, The outer wall of the support shaft is provided with a wire groove, and the bushing is fitted on the part opposite to the wire groove. The length of the wire groove is greater than the axial length of the bushing. It also includes a resolver connecting wire, which passes through the wire groove, with one end connected to the resolver stator and the other end exposed.

6. The hub motor with an external rotary transformer according to claim 1, characterized in that, The annular seal is an oil seal.

7. The hub motor with an external rotary transformer according to claim 2 or 6, characterized in that, The support shaft is provided with a control line passage channel that connects to the inner cavity of the hub. The support shaft is also provided with a resolver passage channel. One end of the resolver passage channel is connected to the receiving groove, and the other end is connected to the control line passage channel. It also includes a resolver connecting wire. One end of the resolver connecting wire is connected to the resolver stator. The resolver connecting wire passes through the resolver passage channel and the control line passage channel in sequence, and the other end is exposed.

8. The hub motor with an external rotary transformer according to any one of claims 1-6, characterized in that, One end cap has a receiving groove on its outer side, and the other end cap has a brake assembly groove on its outer side.

9. The hub motor with an external rotary transformer according to any one of claims 2-5, characterized in that, The outer circular wall of the rotary seal and the inner wall of the receiving groove are fitted with any one or more combinations of interference fit, snap fit, and adhesive fixation; the inner circular wall of the rotary seal and the bushing are rotatably fitted.

10. The hub motor with an external rotary transformer according to any one of claims 2-5, characterized in that, The rotary seal is an oil seal.

11. The hub motor with an external rotary transformer according to any one of claims 1-6, characterized in that, The receiving groove includes a first receiving groove and a second receiving groove that are connected to each other. The resolver stator and resolver rotor are located in the first receiving groove, and the annular seal is located in the second receiving groove. The inner diameter of the first receiving groove is smaller than the inner diameter of the second receiving groove, and a step is formed between the first receiving groove and the second receiving groove.

12. An electric vehicle, comprising a frame, a hub motor mounted on the frame, a tire mounted on the hub motor, and a battery and controller mounted on the frame, characterized in that, The hub motor is the hub motor described in any one of claims 1-10, and the resolver stator is connected to the controller.

Images