Integrated press-in external rotor motor structure

Abstract

The utility model relates to an integrated press-in external rotor motor structure, which comprises a casing, a bottom shaft sleeve and a motor shaft, the casing comprises a top casing and an annular casing, the top casing and the annular casing are connected to form a thin-wall cylindrical structure with an opening at one end, an upper inner hole is arranged on the top casing, the bottom shaft sleeve comprises a bottom plate, one end face of the bottom plate is provided with a plurality of layers of positioning rings, and the motor shaft is arranged on the bottom plate. A lower inner hole is formed in the bottom plate and vertically opposite to the upper inner hole, a shaft body of the motor shaft penetrates through the upper inner hole and is connected with the lower inner hole, and the outer diameter of the bottom shaft sleeve is completely matched with the inner diameter of the opening end of the machine shell. Compared with the existing external rotor motor structure, the external rotor motor structure improves the repeated action of the existing press-in process, changes two-time press-in into one-time press-in, and can effectively improve the productivity. The problem of instability in the prior art can be solved, and the problem of poor perpendicularity caused by poor matching between the motor shaft and the bottom shaft sleeve can be greatly solved.

Description

Technical Field

[0001] This utility model relates to an integrated press-fit external rotor motor structure, belonging to the technical field of mechanical automation. Background Technology

[0002] An external rotor motor has its stator inside and its rotor outside. It has a large moment of inertia and low torque ripple, making it easy to drive directly. It can provide a large torque during operation and eliminates the need for a transmission mechanism. External rotor motors are space-saving, compact, and aesthetically pleasing, and therefore have gained increasing attention in the motor industry in recent years. Currently, most brushless DC motors are of the internal rotor structure. The difference between internal and external rotor motors is that in an internal rotor motor, the rotor is built into the motor housing and tightly connected to the output shaft. In contrast, in an external rotor motor, the rotor is externally mounted, transmitting power through external rotation.

[0003] However, brushless DC motors with an external rotor structure are prone to vibration and noise problems, especially high-speed external rotor motors. Existing external rotor manufacturing processes mainly include screw-fastening, shaft press-fitting, shaft-end-cover riveting, and welding the shaft sleeve to the end cover followed by press-fitting with the knurled shaft. However, all of these processes are difficult to implement stably. For example, when pressing the knurled shaft into the shaft sleeve, deviations in the knurling can easily cause poor shaft perpendicularity, leading to vibration. Furthermore, existing press-fitting methods have low efficiency and inconsistent quality, easily causing loosening during operation. Therefore, there is an urgent need for an external rotor motor structure that can be easily press-fitted in one piece. Utility Model Content

[0004] The summary section of this application is intended to provide a brief overview of the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solutions, nor is it intended to limit the scope of the claimed technical solutions.

[0005] To address the problems and shortcomings of existing technologies, the present invention aims to provide an integrated press-fit external rotor motor structure. By improving the housing, bottom bushing, and motor shaft, the external rotor motor can be press-fitted in a single operation using a riveting fixture. This improves upon the poor vibration and runout issues and unstable riveting processes of existing external rotor motors, thus resolving the problems mentioned in the background section.

[0006] To achieve the above objectives, this utility model provides the following technical solution: It includes a housing, a bottom bushing, and a motor shaft. The housing includes a top shell and an annular shell, which are connected to form a thin-walled cylindrical structure with one open end. The top shell has an upper inner hole. The bottom bushing includes a base plate, with multiple positioning rings on one end face of the base plate. The base plate has lower and upper inner holes corresponding to the upper inner hole. The motor shaft passes through the upper and lower inner holes and is connected to them. The outer diameter of the bottom bushing is fully matched with the inner diameter of the open end of the housing.

[0007] Preferably, multiple pressure relief grooves are formed at the edge of the upper inner hole. The upper inner hole is located in the middle of the top shell of the housing, and pressure relief grooves are formed at the edge of the upper inner hole. These pressure relief grooves can alleviate the pressure on the housing, bottom bushing, and motor shaft during pressing, preventing damage caused by excessive instantaneous pressure, and ensuring safe and stable operation during pressing.

[0008] Preferably, the shaft body connects to the shaft head, and the shaft head is designed with a tapered structure. The motor shaft consists of a shaft body and a shaft head, wherein the shaft body is a smooth shaft structure and the shaft head is a tapered structure. The smooth shaft acts as a sliding bearing, enabling linear motion. Common types of smooth shafts include ordinary linear smooth shafts and linear bearings, which require high surface flatness. Designing the shaft head with a tapered structure makes the snap ring insertion operation more convenient.

[0009] Preferably, a support ring is also provided on one end face of the base plate, located at the edge of the lower inner hole. An upwardly protruding support ring is also connected to one end face of the base plate, and this support ring is positioned at the edge of the lower inner hole. During the pressing process, this can provide a certain degree of support to the motor shaft, preventing motion interference between the motor shaft and the bottom bushing.

[0010] Preferably, the shaft body and the lower inner hole are fitted with an interference fit. An interference fit is a type of tight fit that relies on the interference value between the shaft and the hole to generate elastic pressure between the surfaces of the parts after assembly. Its characteristic is that the diameter of the mating shaft is larger than the diameter of the hole. Furthermore, interference fits are characterized by simple structure and good centering, and can withstand large axial forces, torques, and dynamic loads. Therefore, using an interference fit between the motor shaft body and the lower inner hole of the bottom bushing provides a more secure connection between the two.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] The external rotor motor structure provided by this utility model features a simple structure, easy operation, and stable reliability, effectively solving the problem of shaft detachment caused by insufficient torque. This utility model includes a housing, a bottom bushing, and a motor shaft. The housing is a thin-walled cylindrical structure open at one end. The bottom bushing has multiple positioning rings on one end face of its base plate, which can be securely engaged with the fixing grooves on the riveting fixture. The upper inner hole on the housing and the lower inner hole on the bottom bushing are vertically aligned. The motor shaft passes through the upper and lower inner holes, and the outer diameter of the bottom bushing perfectly matches the inner diameter of the open end of the housing. Compared with existing external rotor motor structures, this utility model improves the repetitive action of the existing pressing process, changing multiple pressing operations to a single pressing operation, which can effectively increase production capacity. It not only solves the instability problem in existing processes but also greatly improves the problem of poor perpendicularity caused by poor fit between the motor shaft and the bottom bushing. Attached Figure Description

[0013] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application.

[0014] In the attached diagram:

[0015] Figure 1 : This is a schematic diagram of the overall structure connection in this utility model;

[0016] Figure 2 This is a schematic diagram of the casing structure in this utility model;

[0017] Figure 3 : This is a schematic diagram of the structure of the bottom bushing of this utility model;

[0018] Figure 4 ; This is a schematic diagram of the structure of the motor shaft in this utility model.

[0019] The markings in the diagram are as follows: 1. Housing; 2. Bottom bushing; 3. Motor shaft; 101. Top shell; 102. Ring shell; 103. Pressure relief groove; 104. Upper inner hole; 201. Base plate; 202. Support ring; 203. Positioning ring; 204. Lower inner hole; 301. Shaft body; 302. Shaft head. Detailed Implementation

[0020] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0021] It should also be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0022] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] This embodiment provides a bushing riveting press-in device, such as... Figures 1 to 4 As shown: It includes a housing 1, a bottom bushing 2, and a motor shaft 3. The housing 1 includes a top shell 101 and an annular shell 102. The top shell 101 and the annular shell 102 are connected to form a thin-walled cylindrical structure with one end open. The top shell 101 has an upper inner hole 104. The bottom bushing 2 includes a base plate 201. One end face of the base plate 201 is provided with multiple positioning rings 203. The base plate 201 has a lower inner hole 204 that corresponds to the upper inner hole 104. The shaft body 301 of the motor shaft passes through the upper inner hole 104 and the lower inner hole 204 and is connected. The outer diameter of the bottom bushing 2 is fully matched with the inner diameter of the open end of the housing 1.

[0024] This embodiment also includes a shaft body 301 connected to a shaft head 302, with the shaft head 302 having a tapered structure. The shaft body 301 and the lower inner hole 204 are fitted with an interference fit. The motor shaft 3 is composed of a shaft body 301 connected to a shaft head 302. The shaft body 301 adopts a smooth shaft structure, and the shaft head adopts a tapered structure. Setting the shaft head 302 as a tapered structure makes the snap ring insertion operation more convenient. Furthermore, the interference fit between the shaft body 301 of the motor shaft 3 and the lower inner hole 204 of the bottom bushing 2 provides a more secure connection between the two.

[0025] This embodiment also includes multiple pressure relief grooves 103 formed on the edge of the upper inner hole 104, and a support ring 202 provided on one end face of the bottom plate 201, located at the edge of the lower inner hole 204. The pressure relief grooves 103 can alleviate the pressure on the housing 1, bottom bushing 2, and motor shaft 3 during pressing, preventing damage caused by excessive instantaneous pressure and ensuring safe and stable operation during pressing. The support ring 202, located at the edge of the lower inner hole 204, can support the motor shaft 2 during pressing, preventing motion interference between the motor shaft 3 and the bottom bushing 2.

[0026] Method of using this utility model

[0027] This invention utilizes a specialized riveting fixture to press-fit the housing 1, bottom bushing 2, and motor shaft 3 together in a single press-fit operation. In use, the motor shaft 3 is first placed into the inner hole of the riveting fixture. The end of the bottom bushing 2 with the support ring 202 and positioning ring 203 is then positioned downwards, with the positioning ring 203 correspondingly inserted into the groove on the riveting fixture for fixation. Next, the outer diameter of the bottom bushing 2 is inserted and fixed along the inner diameter of the housing 1. Finally, the pressure block on the riveting fixture is activated, pushing the upper riveting joint downwards and simultaneously compressing the housing 1, bottom bushing 2, and motor shaft 3. This compression achieves a complete fit between the housing 1 and the bottom bushing 2. Additionally, the embossing block on the riveting fixture can create embossing at the edge of the housing 1. Furthermore, the pressure relief groove 103 effectively alleviates the pressure during the pressing of the housing 1, bottom bushing 2, and motor shaft 3, preventing damage caused by excessive instantaneous pressure.

[0028] In the description of this utility model, it should be understood that the indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this utility model and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0029] In addition to the embodiments described above, this utility model may have other implementation methods. Those skilled in the art can still modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A one-piece press-fit external rotor motor structure, characterized in that: The device includes a housing (1), a bottom bushing (2), and a motor shaft (3). The housing (1) includes a top shell (101) and an annular shell (102). The top shell (101) and the annular shell (102) are connected to form a thin-walled cylindrical structure with one end open. An upper inner hole (104) is opened on the top shell (101). The bottom bushing (2) includes a base plate (201). A plurality of positioning rings (203) are provided on one end face of the base plate (201). A lower inner hole (204) is opened on the base plate (201) and corresponds to the upper inner hole (104). The shaft body (301) of the motor shaft passes through the upper inner hole (104) and the lower inner hole (204) and is connected. The outer diameter of the bottom bushing (2) is fully matched with the inner diameter of the open end of the housing (1).

2. The integral press-fit external rotor motor structure according to claim 1, characterized in that: Multiple pressure relief grooves (103) are provided at the edge of the upper inner hole (104).

3. The integral press-fit external rotor motor structure according to claim 1, characterized in that: The shaft body (301) is connected to the shaft head (302), and the shaft head (302) is set as a tapered structure.

4. The integral press-fit external rotor motor structure according to claim 1, characterized in that: The bottom plate (201) is also provided with a support ring (202) on one end face, and is located at the edge of the lower inner hole (204).

5. The integral press-fit external rotor motor structure according to claim 3, characterized in that: The shaft body (301) and the lower inner hole (204) are interference fit.

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