Motor shaft and hub motor

Abstract

The utility model discloses a motor shaft and a hub motor, and relates to the field of hub motors. According to the technical scheme, the sun gear assembly is characterized by comprising a first shaft and a second shaft, a sun gear clearance fit section is formed at the inner side end of the first shaft, a fixing hole is formed in the inner end face of the second shaft, and the sun gear clearance fit section is embedded in the fixing hole. The motor shaft is formed by connecting the first shaft and the second shaft, a split through shaft type structure is formed, the motor shaft is suitable for an outer rotor hub motor, the reduction ratio of the hub motor can be increased by being matched with a sun gear with a small tooth number, the structure is simple, and the production cost is low.

Description

Technical Field

[0001] The utility model relates to the field of in-wheel motors, and more specifically, to a motor shaft and an in-wheel motor. Background Art

[0002] There are mainly two forms of the motor shaft of the in-wheel motor, namely the through-shaft type and the split-shaft type. Among them, the outer-rotor in-wheel motor generally adopts the through-shaft type of motor shaft, as shown in the Chinese patent with the authorization announcement number CN111525732B. The inner-rotor in-wheel motor generally adopts the split-shaft type of motor shaft, as shown in the Chinese patent with the authorization announcement number CN111327155B.

[0003] In the outer-rotor in-wheel motor, a planetary reduction mechanism is usually provided, and the sun gear of the planetary reduction mechanism is sleeved on the motor shaft. In order to increase the reduction ratio, the number of teeth of the sun gear can be reduced. However, in order to ensure the structural strength and the installation of the sun gear, it is difficult to reduce the diameter of the through-shaft type of motor shaft, so it is difficult to increase the reduction ratio by reducing the number of teeth of the sun gear. For the inner-rotor in-wheel motor, the split-shaft type of motor shaft can be used to optimize the number of teeth of the sun gear to increase the reduction ratio, but the core structure of the inner-rotor in-wheel motor is relatively complex and the cost is relatively high. Summary of the Utility Model

[0004] Aiming at the deficiencies of the existing technology, one of the purposes of the present utility model is to provide a motor shaft, which adopts a split through-shaft structure, is applicable to the outer-rotor in-wheel motor, is beneficial to matching a sun gear with a smaller number of teeth to increase the reduction ratio of the in-wheel motor, and has a simple structure and a lower production cost.

[0005] To achieve the above purpose, the present utility model provides the following technical solutions:

[0006] A motor shaft includes a first shaft and a second shaft. An inner end of the first shaft forms a sun gear clearance fit section, and a fixing hole is provided on an inner end face of the second shaft. The sun gear clearance fit section is embedded in the fixing hole.

[0007] Further, an interference fit is provided between the sun gear clearance fit section and the fixing hole; or, a thread pair is provided between the sun gear clearance fit section and the fixing hole; or, the first shaft and the second shaft are fixed by welding; or, a fastener in contact with the sun gear clearance fit section is embedded on the second shaft.

[0008] Further, an exhaust hole communicating with an inner end of the fixing hole is provided on an outer side wall of the second shaft; or, an exhaust hole extending to an inner end face of the second shaft is provided on an inner side wall of the fixing hole.

[0009] Further, an adhesive is provided between the sun gear clearance fit section and the fixing hole.

[0010] Further, an adhesive groove for accommodating an adhesive is provided on the outer side wall of the sun gear clearance fit section.

[0011] Further, the adhesive groove is provided at the end of the sun gear clearance fit section, and the adhesive groove includes an axial opening.

[0012] Further, a relief ring groove is provided on the part of the sun gear clearance fit section that is exposed outside the fixing hole.

[0013] Further, a first threaded section is provided at the outer end of the first shaft, and a second threaded section is provided at the outer end of the second shaft.

[0014] Further, a lead wire channel is provided on the first shaft.

[0015] Another object of the present invention is to provide a hub motor, which includes the above-mentioned motor shaft; the hub motor further includes a sun gear sleeved on the sun gear clearance fit section, and there is a clearance fit between the sun gear and the sun gear clearance fit section.

[0016] In summary, the present invention has the following beneficial effects:

[0017] 1. The motor shaft adopts a split through-shaft structure, which is applicable to an outer rotor hub motor, is beneficial to matching a sun gear with a smaller number of teeth to increase the reduction ratio of the hub motor, and has a simple structure and low production cost;

[0018] 2. The first shaft and the second shaft are independently processed and then assembled. Then, according to needs, the diameter of the sun gear clearance fit section can be optimized. By reducing the diameter of the sun gear clearance fit section, a smaller-sized sun gear can be matched, and thus the reduction ratio can be increased by reducing the number of teeth of the sun gear;

[0019] 3. The adhesive groove includes an axial opening. Then, when the sun gear clearance fit section is completely embedded, the adhesive can be injected into the fixing hole through the vent hole and then filled into the adhesive groove, which not only does not affect the installation of the sun gear clearance fit section but also can use the adhesive to improve the connection stability;

[0020] 4. There is a clearance fit between the sun gear and the sun gear clearance fit section, and the clearance is small. The use of a relief ring groove is beneficial to avoiding contact friction between the sun gear and the sun gear clearance fit section and can reduce the processing difficulty. Description of the Drawings

[0021] Figure 1 Structural schematic diagram of the motor shaft in Embodiment 1 Figure 1 ;

[0022] Figure 2Schematic structure of the motor shaft in Embodiment 1 Figure 2 ;

[0023] Figure 3 Schematic structural diagram of the in-wheel motor in Embodiment 2

[0024] In the figure: 1. First shaft; 11. Sun gear clearance fit section; 111. Relief ring groove; 112. Bonding groove; 12. First thread section; 13. Lead wire channel; 2. Second shaft; 21. Fixing hole; 22. Second thread section; 23. Vent hole; 3. Rotor; 4. Sun gear Specific embodiments

[0025] The present utility model will be further described in detail below with reference to the accompanying drawings

[0026] This specific embodiment is only an explanation of the present utility model, and it is not a limitation of the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as they are within the scope of the claims of the present utility model, they are protected by the Patent Law Embodiment 1

[0027] A motor shaft, referring to Figure 1 and Figure 2 , which includes a first shaft 1 and a second shaft 2; the inner end of the first shaft 1 forms a sun gear clearance fit section 11, and the outer end of the first shaft 1 is provided with a first thread section 12; in this embodiment, a lead wire channel 13 is also provided on the first shaft 1 for leading the wire harness in the in-wheel motor to the outside; the inner end face of the second shaft 2 is provided with a fixing hole 21, and the outer end of the second shaft 2 is provided with a second thread section 22; after the first shaft 1 and the second shaft 2 are connected, the first thread section 12 and the second thread section 22 are used to fix the motor shaft and the in-wheel motor

[0028] Referring to Figure 1 and Figure 2 , specifically, in this embodiment, the sun gear clearance fit section 11 is embedded in the fixing hole 21 to realize the connection between the first shaft 1 and the second shaft 2; preferably, an interference fit is provided between the sun gear clearance fit section 11 and the fixing hole 21, so as to realize the fixed connection between the first shaft 1 and the second shaft 2; using an interference fit not only facilitates assembly, but also helps to improve the assembly accuracy and the coaxiality of the motor shaft; on the basis of using the sun gear clearance fit section 11 and the fixing hole 21, other methods can also be used to realize the fixed connection between the first shaft 1 and the second shaft 2, which is not limited here

[0029] Referring to Figure 1 and Figure 2, in this embodiment, the first shaft 1 and the second shaft 2 are two independent parts. After the first shaft 1 and the second shaft 2 are connected, a split through-shaft structure is formed. That is to say, after the first shaft 1 and the second shaft 2 are connected, a continuously axially motor shaft is formed. After the two ends of the motor shaft are fixed, the motor shaft can be fixed in place. The first shaft 1 and the second shaft 2 are processed independently and then assembled. Then, according to needs, the diameter of the sun gear clearance fit section 11 can be optimized. By reducing the diameter of the sun gear clearance fit section 11, a smaller-sized sun gear can be matched, and thus the reduction ratio can be increased by reducing the number of teeth of the sun gear. Specifically, during installation, the sun gear clearance fit section 11 is passed through the sun gear and then embedded into the fixing hole 21, thereby realizing the assembly of the motor shaft and the installation of the sun gear. The sun gear clearance fit section 11 is located in the middle part of the motor shaft. By optimizing the reduction of the diameter of this section, the structural strength of the motor shaft will not be affected.

[0030] Refer to Figure 1 and Figure 2 , the motor shaft in this embodiment adopts a split through-shaft structure, which is suitable for an outer rotor hub motor, is beneficial to matching a sun gear with fewer teeth to increase the reduction ratio of the hub motor, and has a simple structure and low production cost.

[0031] Refer to Figure 1 and Figure 2 , preferably, an exhaust hole 23 communicating with the inner end of the fixing hole 21 is provided on the outer side wall of the second shaft 2. When the sun gear clearance fit section 11 is embedded into the fixing hole 21, the air in the fixing hole 21 is discharged from the exhaust hole 23, which is beneficial to the proper installation of the sun gear clearance fit section 11. Preferably, an adhesive is provided between the sun gear clearance fit section 11 and the fixing hole 21, so as to improve the connection stability. Preferably, an adhesive groove 112 for accommodating the adhesive is provided on the outer side wall of the sun gear clearance fit section 11, which can avoid the adhesive affecting the installation of the sun gear clearance fit section 11. Preferably, the adhesive groove 112 is provided at the end of the sun gear clearance fit section 11, and the adhesive groove 112 includes an axial opening. By providing the adhesive groove 112 at the end, the adhesive can be further prevented from affecting the installation of the sun gear clearance fit section 11. The adhesive groove 112 includes an axial opening, so that after the sun gear clearance fit section 11 is completely embedded, the adhesive can be injected into the fixing hole 21 through the exhaust hole 23 and then filled into the adhesive groove 112. In this way, it not only does not affect the installation of the sun gear clearance fit section 11, but also can use the adhesive to improve the connection stability.

[0032] Refer to Figure 1, preferably, a relief annular groove 111 is provided on the part of the sun gear clearance fit section 11 exposed outside the fixing hole 21; after installation, the sun gear is sleeved on the relief annular groove 111; there is a clearance fit between the sun gear and the sun gear clearance fit section 11, and the clearance is small. The use of the relief annular groove 111 helps to avoid contact friction between the sun gear and the sun gear clearance fit section 11 and can reduce the processing difficulty. Embodiment 2:

[0033] A hub motor, referring to Figures 1 to 3 , which includes the motor shaft in Embodiment 1, and further includes a rotor 3 and a sun gear 4 connected to the rotor 3; the hub motor in this embodiment is an outer rotor hub motor, the motor shaft is fixed, and the torque of the rotor 3 is transmitted through the sun gear 4; the sun gear 4 is sleeved on the sun gear clearance fit section 11 of the motor shaft, and there is a clearance fit between the sun gear 4 and the sun gear clearance fit section 11.

Claims

1. A motor shaft, characterized in that: It includes a first shaft and a second shaft. An inner end of the first shaft forms a sun gear clearance fit section, and a fixing hole is provided on an inner end face of the second shaft. The sun gear clearance fit section is embedded in the fixing hole.

2. The motor shaft according to claim 1, characterized in that: An interference fit is provided between the sun gear clearance fit section and the fixing hole; alternatively, a thread pair is provided between the sun gear clearance fit section and the fixing hole; alternatively, the first shaft and the second shaft are fixed by welding; alternatively, a fastener in contact with the sun gear clearance fit section is embedded on the second shaft.

3. The motor shaft according to claim 1, wherein: An exhaust hole communicating with an inner end of the fixing hole is provided on an outer side wall of the second shaft; alternatively, an exhaust hole extending to the inner end face of the second shaft is provided on an inner side wall of the fixing hole.

4. The motor shaft according to claim 1, wherein: An adhesive is provided between the sun gear clearance fit section and the fixing hole.

5. The motor shaft according to claim 4, wherein: An adhesive groove for accommodating the adhesive is provided on an outer side wall of the sun gear clearance fit section.

6. The motor shaft according to claim 5, characterized in that: The adhesive groove is provided at an end of the sun gear clearance fit section, and the adhesive groove includes an axial opening.

7. The motor shaft according to claim 1, wherein: A relief ring groove is provided on a part of the sun gear clearance fit section exposed from the fixing hole.

8. The motor shaft according to claim 1, characterized in that: A first thread section is provided at an outer end of the first shaft, and a second thread section is provided at an outer end of the second shaft.

9. The motor shaft according to claim 1, wherein: A lead channel is provided on the first shaft.

10. A hub motor, characterized in that: It includes the motor shaft according to any one of claims 1-9; the in-wheel motor further includes a sun gear sleeved on the sun gear clearance fit section, and a clearance fit is provided between the sun gear and the sun gear clearance fit section.

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