A new type of permanent magnet motor

Abstract

This invention discloses a novel permanent magnet motor. The motor housing contains a stator assembly, a rotor assembly, and a metal shaft. The rotor assembly includes a plastic part and a magnetic ring integrally molded with the plastic part. A core hole is formed in the core of the plastic part. An elastic component is embedded within the assembly housing of the plastic part. The elastic component includes a movable slider with a semi-circular groove on its inner surface. A compression spring is installed at the outer end of the movable slider within the assembly housing. The portion of the core hole radially aligned with the semi-circular groove of the slider is a semi-circular groove in the plastic part with a semi-circular cross-section. The semi-circular groove of the plastic part and the semi-circular groove of the slider together form a circular shaft hole that mates with the metal shaft. The rotor assembly improves the fitting accuracy with the metal shaft, thereby reducing shaking during rotation and improving rotational smoothness, as well as reducing motor vibration and noise. Therefore, this invention has the advantages of novel structural design, good operational smoothness, and low vibration and noise.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a novel permanent magnet motor. Background Technology

[0002] For a motor rotor without a central metal shaft, the core of the motor rotor has a shaft hole structure. During the motor assembly process, the shaft hole structure of the motor rotor is sleeved with the central metal shaft set on the housing and achieves clearance fit, thereby enabling the motor shaft to rotate relative to the housing.

[0003] Among them, the Chinese invention patent with patent number ZL202421667108.1 and patent name: "An Open-Type Stepper Motor" specifically discloses the following technical solution: An open-type stepper motor includes a fixed base and a motor body. The motor body includes a motor housing and a stator assembly and a rotor assembly respectively installed inside the motor housing. The rotor assembly includes a plastic part and a magnet. The plastic part and the magnet are injection molded into an integral structure. The fixed base has a housing positioning groove corresponding to the motor housing. The bottom surface of the housing positioning groove is provided with a protruding rotor positioning shaft (central metal shaft). The rear end of the motor housing is embedded and positioned in the housing positioning groove of the fixed base. The core of the plastic part has a shaft hole extending along the axial direction of the plastic part and opening to the rear. The rotor positioning shaft of the fixed base is inserted into the shaft hole of the plastic part. That is, the plastic part of the rotor assembly is fitted around the rotor positioning shaft of the fixed base through its shaft hole, and the plastic part and the rotor positioning shaft are in clearance fit.

[0004] It should be noted that the rotor assembly of the aforementioned open-type stepper motor has the following defects: Specifically, during the injection molding process of the magnet and the plastic part, the plastic part needs to have a shaft hole. This shaft hole has a draft angle during injection molding to ensure smooth demolding. This draft angle results in a tapered shaft hole (i.e., a tapered hole structure, small at the head and large at the root). When this tapered shaft hole is rotatably connected to the rotor positioning shaft with a clearance fit, the radial clearance between the inner wall of the shaft hole and the rotor positioning shaft is uneven, i.e., small at the head and large at the root. This leads to problems such as large clearance, significant wobble, and poor precision, resulting in rotor wobble, shaking / vibration, and high noise during motor operation. The longer the shaft hole of the plastic part, the more pronounced these problems become. Summary of the Invention

[0005] The purpose of this invention is to provide a novel permanent magnet motor that addresses the shortcomings of existing technologies. This novel permanent magnet motor has a novel structural design, good smooth operation, and low vibration and noise.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions.

[0007] A novel permanent magnet motor includes a motor housing, an inner cavity formed inside the motor housing, and a stator assembly and a rotor assembly embedded in the inner cavity; The rotor assembly includes a plastic part and a magnetic ring that is fitted around the plastic part and arranged coaxially with the plastic part. The plastic part and the magnetic ring are injection molded into an integral structure. The core of the plastic part has a core hole. A metal shaft that extends into the housing cavity and is inserted into the core hole of the plastic part is fastened to the motor housing. The plastic part has an internal component receiving cavity that communicates with the core hole. An elastic component is embedded in the component receiving cavity. The elastic component includes a movable slider that extends along the axial direction of the core hole. The inner surface of the movable slider has a slider semicircular groove with a semicircular cross-section that passes through the axial direction of the core hole. A compression spring is installed in the component receiving cavity on the outer end side of the movable slider, arranged radially along the plastic part. The inner end of the compression spring abuts against the movable slider, and the outer end of the compression spring abuts against the plastic part. The part of the core hole that is radially aligned with the semicircular groove of the slider is a semicircular groove of the plastic part with a semicircular cross-section. The semicircular groove of the plastic part and the semicircular groove of the slider together form a circular shaft hole that mates with the metal shaft.

[0008] The component cavity contains at least two compression springs arranged sequentially at intervals along the axial direction of the core hole, located at the outer end of the movable slider. The inner end of each compression spring abuts against the movable slider, and the outer end of each compression spring abuts against the plastic part.

[0009] The movable slider is provided with an outwardly protruding spring positioning protrusion for each compression spring, and the inner end of each compression spring is respectively fitted around the corresponding spring positioning protrusion.

[0010] The upper end of the plastic part is provided with an output gear part arranged coaxially with the plastic part. The output gear part and the plastic part are an integral structure, and the output gear part extends to the upper end of the motor housing.

[0011] The motor housing includes an upper shell and a lower shell screwed to the lower end of the upper shell. The housing cavity is formed by the upper shell and the lower shell together. The stator assembly is secured between the upper and lower housings, and the metal shaft is fastened to the middle of the lower housing. The stator assembly includes silicon steel sheets and coil windings wound around the silicon steel sheets.

[0012] The plastic part is formed with an upper limit flange located on the upper end side of the magnetic ring and a lower limit flange located on the lower end side of the magnetic ring. The upper limit flange, the lower limit flange and the plastic part are an integral structure, and the magnetic ring is axially limited between the upper limit flange and the lower limit flange.

[0013] The magnetic ring has inwardly opening limiting grooves at its upper and lower edges, and the plastic part has limiting protrusions that fill the grooves.

[0014] The magnetic ring is a multi-stage magnetic ring structure with oblique angle multi-pole magnetization.

[0015] Compared with the prior art, the present invention has the following beneficial effects: Specifically, neither the semi-circular groove of the rubber part nor the semi-circular groove of the slider in the rotor assembly requires draft angle. Under the elastic force of the compression spring, the inner wall of the semi-circular groove of the rubber part and the inner wall of the semi-circular groove of the slider are tightly fitted with the outer circumferential surface of the metal shaft. Compared with the prior art, the circular shaft hole of the present invention can effectively avoid the problem of inconsistent radial clearance caused by draft angle. That is, the rotor assembly can effectively improve the fitting accuracy with the metal shaft, thereby effectively reducing the shaking during rotation and improving the smoothness of rotation, and effectively reducing the vibration and noise of the motor product. Therefore, the novel permanent magnet motor of the present invention has the advantages of novel structural design, good smooth operation, and low vibration and noise. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings, but the embodiments in the drawings do not constitute any limitation on the present invention.

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Figure 2 This is an exploded view of the present invention.

[0019] Figure 3 This is a cross-sectional schematic diagram of the present invention.

[0020] Figure 4 This is a schematic diagram of the rotor assembly of the present invention.

[0021] Figure 5 This is a schematic diagram of the rotor assembly of the present invention from another perspective.

[0022] Figure 6 This is a cross-sectional schematic diagram of the rotor assembly of the present invention.

[0023] Figure 7 This is a schematic diagram of the structure of the elastic component of the present invention.

[0024] exist Figures 1 to 7 This includes: 1-Motor housing; 11-Housing cavity; 12-Upper shell; 13-Lower shell; 2-Stator assembly; 21-Silicon steel sheet; 22-Coil winding; 3-Rotor assembly; 31-Plastic part; 311-Core hole; 3111-Semi-circular groove of plastic part; 312-Assembly cavity; 313-Upper limit flange; 314-Lower limit flange; 315-Limiting protrusion; 32-Magnetic ring; 321-Limiting groove; 33-Elastic component; 331-Moving slider; 3311-Slider semi-circular groove; 3312-Spring positioning protrusion; 332-Compression spring; 34-Output gear; 4-Metal shaft. Detailed Implementation

[0025] The present invention will now be described in conjunction with specific embodiments.

[0026] Example 1, as Figures 1 to 3 As shown, a novel permanent magnet motor includes a motor housing 1, with a housing cavity 11 formed inside the motor housing 1, and a stator assembly 2 and a rotor assembly 3 embedded in the housing cavity 11.

[0027] Among them, such as Figures 2 to 6 As shown, the rotor assembly 3 includes a plastic part 31 and a magnetic ring 32 that is fitted around the plastic part 31 and arranged coaxially with the plastic part 31. The plastic part 31 and the magnetic ring 32 are injection molded into an integral structure. The core of the plastic part 31 has a core hole 311. A metal shaft 4 that extends into the housing cavity 11 and is inserted into the core hole 311 of the plastic part 31 is fastened to the motor housing 1.

[0028] Furthermore, such as Figure 2 , Figure 3 , Figure 5 , Figure 6 as well as Figure 7 As shown, the plastic part 31 has an internal component receiving cavity 312 that communicates with the core hole 311. An elastic component 33 is embedded in the component receiving cavity 312. The elastic component 33 includes a movable slider 331 that extends along the axial direction of the core hole 311. The inner surface of the movable slider 331 has a slider semicircular groove 3311 with a semicircular cross-section that passes through the axial direction of the core hole 311.

[0029] Furthermore, such as Figure 2 , Figure 3 , Figure 5 , Figure 6 as well as Figure 7 As shown, a compression spring 332 is installed in the component receiving cavity 312 on the outer end side of the movable slider 331, arranged radially along the plastic part 31. The inner end of the compression spring 332 abuts against the movable slider 331, and the outer end of the compression spring 332 abuts against the plastic part 31.

[0030] In addition, such as Figure 5 and Figure 6 As shown, the part of the core hole 311 that is radially aligned with the slider semicircular groove 3311 is a plastic semicircular groove 3111 with a semicircular cross-section. The plastic semicircular groove 3111 and the slider semicircular groove 3311 together form a circular shaft hole that mates with the metal shaft 4.

[0031] It should be noted that the axial length of the semicircular groove 3311 of the slider is equal to the axial length of the semicircular groove 3111 of the plastic part; for motor products of different sizes and specifications, the length of the movable slider 331 is adapted to the length of the metal shaft 4, that is, the longer the metal shaft 4 is, the longer the movable slider 331 is.

[0032] It should be emphasized that, for the rotor assembly 3 of this embodiment, during the injection molding of the plastic part 31, the semi-circular groove 3111 of the plastic part opens towards the assembly receiving cavity 312, meaning that there is no draft angle requirement for the semi-circular groove 3111 during injection molding; similarly, for the movable slider 331 of this embodiment, it is independent of the plastic part 31, meaning that there is also no draft angle requirement for the slider semi-circular groove 3311 of the movable slider 331; when the metal shaft 4 is inserted into the circular shaft hole formed by the semi-circular groove 3111 of the plastic part and the slider semi-circular groove 3311, the elastic force of the compression spring 332 causes the inner wall of the slider semi-circular groove 3311 to contact the inner wall of the slider semi-circular groove 3311. The outer circumferential surface of the metal shaft 4 is in stable and reliable contact and tightly fitted, and the elastic force of the compression spring 332 also makes the outer circumferential surface of the metal shaft 4 in stable and reliable contact and tightly fitted with the inner wall of the semi-circular groove 3111 of the plastic part. Therefore, the circular shaft hole of this embodiment can effectively avoid the problem of inconsistent radial clearance caused by the draft angle in the prior art. That is, the rotor assembly 3 of this embodiment can effectively improve the fitting accuracy with the metal shaft 4, thereby effectively improving the fitting accuracy between the rotor and the metal shaft 4 and reducing the shaking when the rotor rotates. This effectively reduces the shaking during rotation, improves the stability during rotation, and reduces vibration and noise.

[0033] In summary, the novel permanent magnet motor of this embodiment has the advantages of novel structural design, smooth operation, and low vibration and noise through the above structural design. Example 2, as Figure 2 , Figure 3 , Figure 6 as well as Figure 7 As shown, the difference between this embodiment 2 and embodiment 1 is that: at least two compression springs 332 are installed in the component accommodating cavity 312 on the outer end side of the movable slider 331, arranged sequentially and at intervals along the axial direction of the core hole 311. The inner end of each compression spring 332 abuts against the movable slider 331, and the outer end of each compression spring 332 abuts against the plastic part 31.

[0034] In this second embodiment, the movable slider 331 is pushed inward by multiple compression springs 332. The multiple compression springs 332 are arranged sequentially at intervals along the axial direction of the core hole 311. This structural design can effectively ensure the balance of force on the movable slider 331. Example 3, as Figure 6 As shown, the difference between this embodiment 3 and embodiment 2 is that: the movable slider 331 is provided with outwardly protruding spring positioning protrusions 3312 for each compression spring 332, and the inner end of each compression spring 332 is respectively fitted around the corresponding spring positioning protrusion 3312.

[0035] As for the spring positioning protrusion 3312 in this embodiment, it can effectively position the compression spring 332 to ensure the accuracy of the position of each compression spring 332, thereby improving the stability of the overall structure. Example 4, as Figure 1 , Figure 2 , Figure 3 , Figure 4 as well as Figure 6 As shown, the difference between this embodiment four and embodiment one is that: the upper end of the plastic part 31 is provided with an output gear part 34 arranged coaxially with the plastic part 31, the output gear part 34 and the plastic part 31 are an integral structure, and the output gear part 34 extends to the upper end of the motor housing 1.

[0036] In this embodiment, the output gear 34 serves as the power output structure of the rotor assembly 3. During operation, the rotor assembly 3 drives the output gear 34 to rotate synchronously, and the rotating output gear 34 drives the corresponding actuator to operate. Example 5, as Figures 1 to 3 As shown, the difference between this fifth embodiment and the first embodiment is that the motor housing 1 includes an upper housing 12 and a lower housing 13 screwed to the lower end of the upper housing 12. The housing cavity 11 is formed by the upper housing 12 and the lower housing 13 together.

[0037] The stator assembly 2 is fixed between the upper shell 12 and the lower shell 13, and the metal shaft 4 is fastened to the middle of the lower shell 13.

[0038] It should be noted that the stator assembly 2 includes silicon steel sheets 21 and coil windings 22 wound around the silicon steel sheets 21. Example 6, as Figure 2 and Figure 6 As shown, the difference between this sixth embodiment and the first embodiment is that the plastic part 31 is formed with an upper limit flange 313 located on the upper end side of the magnetic ring 32 and a lower limit flange 314 located on the lower end side of the magnetic ring 32. The upper limit flange 313, the lower limit flange 314 and the plastic part 31 are an integral structure, and the magnetic ring 32 is axially limited between the upper limit flange 313 and the lower limit flange 314.

[0039] In addition, such as Figure 2 As shown, the upper and lower edges of the inner circumferential surface of the magnetic ring 32 are respectively provided with inwardly opening limiting grooves 321, and the plastic part 31 is provided with limiting protrusions 315 that fill into the grooves.

[0040] Through the upper limit flange 313 and the lower limit flange 314, the magnetic ring 32 can be axially limited; through the cooperation of the limiting groove 321 and the limiting protrusion 315, the magnetic ring 32 can be radially limited.

[0041] Therefore, through the upper limit flange 313, the lower limit flange 314, the limiting groove 321, and the limiting protrusion 315, this embodiment six can ensure that the magnetic ring 32 is stably and reliably installed on the plastic part 31. Example 7, as Figure 4 and Figure 5 As shown, the difference between this embodiment seven and embodiment one is that the magnetic ring 32 is a multi-level magnetic ring structure with oblique angle multi-pole magnetization.

[0042] The magnetic ring 32 in this embodiment can play the following roles: noise reduction, improved accuracy and stability.

Claims

1. A novel permanent magnet motor, comprising a motor housing (1), wherein the motor housing (1) has a housing cavity (11) formed inside, and a stator assembly (2) and a rotor assembly (3) are embedded in the housing cavity (11); The rotor assembly (3) includes a plastic part (31) and a magnetic ring (32) that is fitted around the plastic part (31) and arranged coaxially with the plastic part (31). The plastic part (31) and the magnetic ring (32) are injection molded into an integral structure. The core of the plastic part (31) has a core hole (311). The motor housing (1) is fastened with a metal shaft (4) that extends into the housing cavity (11) and is inserted into the core hole (311) of the plastic part (31). Its features are: The plastic part (31) has an internal component receiving cavity (312) that communicates with the core hole (311). An elastic component (33) is embedded in the component receiving cavity (312). The elastic component (33) includes a movable slider (331) that extends along the axial direction of the core hole (311). The inner surface of the movable slider (331) has a slider semicircular groove (3311) with a semicircular cross-section that passes through the axial direction of the core hole (311). A compression spring (332) is installed in the component receiving cavity (312) on the outer end side of the movable slider (331) and arranged radially along the plastic part (31). The inner end of the compression spring (332) abuts against the movable slider (331), and the outer end of the compression spring (332) abuts against the plastic part (31). The part of the core hole (311) that is radially aligned with the slider semicircular groove (3311) is a plastic semicircular groove (3111) with a semicircular cross-section. The plastic semicircular groove (3111) and the slider semicircular groove (3311) together form a circular shaft hole that mates with the metal shaft (4). At least two compression springs (332) are arranged sequentially at intervals along the axial direction of the core hole (311) on the outer end side of the movable slider (331) in the component receiving cavity (312). The inner end of each compression spring (332) abuts against the movable slider (331), and the outer end of each compression spring (332) abuts against the plastic part (31). The movable slider (331) is provided with outwardly protruding spring positioning protrusions (3312) corresponding to each compression spring (332), and the inner end of each compression spring (332) is respectively fitted around the corresponding spring positioning protrusion (3312); The plastic part (31) is formed with an upper limit flange (313) located on the upper end side of the magnetic ring (32) and a lower limit flange (314) located on the lower end side of the magnetic ring (32). The upper limit flange (313), the lower limit flange (314) and the plastic part (31) are integral structures. The magnetic ring (32) is axially limited between the upper limit flange (313) and the lower limit flange (314). The upper and lower edges of the inner circumferential surface of the magnetic ring (32) are respectively provided with inwardly opening limiting grooves (321), and the plastic part (31) is provided with limiting protrusions (315) that fill the grooves.

2. The novel permanent magnet motor according to claim 1, characterized in that: The upper end of the plastic part (31) is provided with an output gear part (34) arranged coaxially with the plastic part (31). The output gear part (34) and the plastic part (31) are an integral structure. The output gear part (34) extends to the upper end of the motor housing (1).

3. A novel permanent magnet motor according to claim 1, characterized in that: The motor housing (1) includes an upper shell (12) and a lower shell (13) screwed to the lower end of the upper shell (12). The housing cavity (11) is formed by the upper shell (12) and the lower shell (13). The stator assembly (2) is locked between the upper shell (12) and the lower shell (13), and the metal shaft (4) is fastened to the middle of the lower shell (13); The stator assembly (2) includes silicon steel sheets (21) and coil windings (22) wound around the silicon steel sheets (21).

4. A novel permanent magnet motor according to claim 1, characterized in that: The magnetic ring (32) is a multi-stage magnetic ring structure with oblique angle multi-pole magnetization.

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