CN216530778U - Brushless motor outer rotor structure - Google Patents

Abstract

The utility model belongs to the field of brushless motors, and particularly relates to an outer rotor structure of a brushless motor. It comprises the following steps: the rotor comprises a rotor shaft, an impeller and a magnetic structure; the impeller is sleeved on the rotor shaft, and an anti-skid structure is arranged at the sleeved position of the impeller and the rotor shaft; the anti-skid structure comprises a radial anti-skid structure and an axial anti-skid structure; the impeller comprises fan blades and a sleeve extending along the axial direction of the rotor shaft; the magnetic structure comprises a magnetic yoke and a magnetic shoe; the magnet yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve. The utility model greatly reduces the assembly difficulty of the whole outer rotor structure through reasonable structural design, can effectively improve the concentricity of the structures such as the impeller, the rotor shaft, the magnetic yoke and the like while ensuring the stability of the whole structure, and simultaneously reasonably adjusts and improves the materials of the parts such as the impeller, the rotor shaft, the magnetic yoke and the like.

Description

Brushless motor outer rotor structure

Technical Field

The utility model belongs to the field of brushless motors, and particularly relates to an outer rotor structure of a brushless motor.

Background

A brushless motor is a typical mechatronic product, and an outer rotor brushless motor is a typical brushless motor having an outer rotor structure. Compared with the inner rotor brushless motor with the same size, the outer rotor brushless motor has the advantages of large torque, large rotational inertia, easiness in heat dissipation, larger flat ratio and the like, and products which need large torque and high rotation speed increasingly adopt the outer rotor direct-drive motor, such as unmanned aerial vehicles, aeromodelling, electric chain saws, grass trimmers and the like.

The rotor shaft of the low-power outer rotor brushless motor and the motor magnetic yoke (steel ring sleeve) are generally combined in a manner of interference fit press fitting, stamping, glue bonding and the like. The magnetic yoke of the outer rotor motor is one of the parts with the largest torque inertia of the motor, and the concentricity of the inner circle and the outer circle of the outer rotor motor and the axis of the rotor and the verticality of the end face and the axis almost determine the dynamic unbalance of the rotor. The motor is limited by production process and equipment, and the magnet yoke and the rotor shaft of the motor always have different degrees of non-concentricity, so that the unbalance of the rotor is large, the dynamic balance of the rotor is required, otherwise, the motor can vibrate when running at high speed, and the motor cannot be used seriously.

Therefore, how to improve the structural concentricity, and further improve the structural stability and the working stability of the composite material is a hot point of research.

Disclosure of Invention

The utility model provides an outer rotor structure of a brushless motor, aiming at solving the problems that the structural stability of the outer rotor of the existing brushless motor is poor, the structural components are complicated, the assembly process of the outer rotor is easy to generate decentration in different degrees, the structural unbalance is large, the motion stability is easy to be poor due to material factors in the actual use process, and the like.

The utility model aims to:

firstly, the stability of the outer rotor structure is improved;

secondly, the assembly process of the outer rotor structure is simplified, and the concentricity of the outer rotor structure is improved;

and thirdly, the structural stability of the outer rotor structure in the operation and use process is improved.

In order to achieve the purpose, the utility model adopts the following technical scheme.

A brushless motor outer rotor structure comprising:

the rotor comprises a rotor shaft, an impeller and a magnetic structure;

the impeller is sleeved on the rotor shaft, and an anti-skid structure is arranged at the sleeved position of the impeller and the rotor shaft;

the anti-skid structure comprises a radial anti-skid structure and an axial anti-skid structure;

the impeller comprises fan blades and a sleeve extending along the axial direction of the rotor shaft;

the magnetic structure comprises a magnetic yoke and a magnetic shoe;

the magnet yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve.

As a preference, the first and second liquid crystal compositions are,

the magnetic yoke is of an annular structure and is fixedly connected with the inner wall of the sleeve in an anti-slip matching manner.

As a preference, the first and second liquid crystal compositions are,

the radial anti-slip structure is a knurling arranged on the outer surface of the rotor shaft;

the axial anti-slip structure is a cutting groove arranged on the outer surface of the rotor shaft.

As a preference, the first and second liquid crystal compositions are,

the knurls are straight knurls;

the cutting groove is an annular inwards-sunk cutting groove.

As a preference, the first and second liquid crystal compositions are,

the axial anti-slip structure is axially arranged at two ends of the radial anti-slip structure along the rotor shaft.

Preferably, the outer side of the magnetic yoke is provided with an anti-slip groove, and the inner wall of the sleeve is correspondingly provided with an anti-slip bulge matched with the anti-slip groove to form anti-slip matching between the magnetic yoke and the inner wall of the sleeve.

As a preference, the first and second liquid crystal compositions are,

the anti-skid groove is a trapezoidal groove or a rounded triangular groove.

As a preference, the first and second liquid crystal compositions are,

the rotor shaft is a plastic rotor shaft;

the impeller is a plastic impeller;

the magnetic yoke is a plastic magnetic yoke.

The utility model has the beneficial effects that:

through the structural design of rationalization for the assembly degree of difficulty of whole external rotor structure descends by a wide margin, can effectively improve the concentricity of structures such as impeller, rotor shaft and yoke when guaranteeing overall structure stability, carries out reasonable adjustment to the material of parts such as its impeller, rotor shaft and yoke simultaneously and improves.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural diagram of a conventional outer rotor structure;

FIG. 3 is a schematic view of the construction of a rotor shaft according to the present invention;

FIG. 4 is a schematic view of a yoke according to the present invention;

FIG. 5 is a schematic view of the structure of the yoke and sleeve in cooperation with each other according to the present invention;

FIG. 6 is a schematic diagram of the combination of an existing outer rotor structure steel ring sleeve and a magnetic shoe retainer;

in the figure: 100 rotor shafts, 101 knurls, 102 grooves, 200 impellers, 201 fan blades, 202 sleeves, 2021 anti-skidding protrusions, 203 steel ring sleeves, 204 magnetic shoe retainers, 2041 clamping grooves, 300 magnetic yokes, 301 anti-skidding grooves, 302 clamping grooves, 400 magnetic shoes and 500 inserts.

Detailed Description

The utility model is described in further detail below with reference to specific embodiments and the attached drawing figures. Those skilled in the art will be able to implement the utility model based on these teachings. Moreover, the embodiments of the present invention described in the following description are generally only some embodiments of the present invention, and not all embodiments. Therefore, all other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without any creative effort shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "circumferential", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., and "several" means one or more unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all those known to those skilled in the art.

Examples

An outer rotor structure of a brushless motor shown in fig. 1 specifically includes:

a rotor shaft 100, an impeller 200, and a magnetically active structure;

the impeller 200 is sleeved on the rotor shaft 100, and an anti-skid structure is arranged at the position of the rotor shaft 100, which is opposite to the position where the impeller 200 is sleeved;

the anti-slip structure specifically comprises a radial anti-slip structure for preventing the impeller 200 from slipping circumferentially relative to the rotor shaft 100 and an axial anti-slip structure for preventing the impeller 200 from slipping axially relative to the rotor shaft 100;

as shown in particular in fig. 3;

the radial anti-skid structure comprises but is not limited to a conventional anti-skid structure of which the outer surface is provided with knurls or is subjected to damping treatment to form a damping layer or is clamped, matched, fixed and the like, but for the utility model, the embodiment adopts relatively optimal outer surface knurls, the knurls specifically adopt straight knurls 101, and the lines are along the axial direction of the rotor shaft 100;

the axial anti-slip structure includes, but is not limited to, a conventional anti-slip structure such as a damping layer formed by knurling or damping treatment or a clamping fit fixing, but for the present invention, a relatively optimal clamping fit structure is adopted in this embodiment, specifically, cutting grooves 102 which are annularly recessed in the circumferential direction are arranged at two ends of the knurling along the axial direction of the rotor shaft 100;

compared with a mode of performing bidirectional antiskid on a single structure by adopting a reticulate pattern knurling or clamping matching fixing mode, the mode that bidirectional antiskid structures are mutually separated can prevent the antiskid structures from being damaged due to stress concentration or local concentrated abrasion in the working process of an outer rotor structure, and compared with the traditional outer rotor structure shown in fig. 2, the mode that the antiskid structures are matched by the insert 500 is adopted, the insert 500 is arranged between the impeller 200 and the rotor shaft 100 to realize axial antiskid, but the arrangement of the insert 500 is easy to increase the unbalance amount of the rotor, and the rotor shaft 100 and the impeller 200 are combined by adopting interference fit press mounting or stamping and other modes, so that the increase of the insert 500 can increase the assembly difficulty and simultaneously has the problem that the insert 500 is easy to generate abrasion deformation in the assembly process of the impeller 200, and the actual antiskid effect is poor;

therefore, the knurling and the cutting grooves 102 are respectively and independently arranged, so that the knurling and the cutting grooves form skid resistance in one direction, the problems of easy damage and the like are avoided, and the operations of stamping, press mounting and the like are facilitated;

the magnetic structure comprises a magnetic yoke 300 and a magnetic shoe 400, the whole magnetic structure is arranged on the inner side of an impeller 200 along the axial direction of a rotor shaft 100 and is connected with the impeller 200 in a matched mode, the edge of the specific impeller 200 extends along the inner side of the axial direction of the rotor shaft 100 to form a sleeve 202, the magnetic yoke 300 is arranged in the sleeve 202 and is connected with the inner wall of the sleeve 202 in a matched mode, the matched connection mode comprises but is not limited to conventional connection modes such as clamping, bonding and the like, the embodiment adopts a connection mode of interference clamping, and the magnetic yoke 300 is embedded into the sleeve 202 in a press-fitting or stamping mode;

specifically, the magnet yoke 300 of the present invention is provided with an anti-slip groove 301 on the outer side thereof, and a card groove 302 for mounting the magnetic shoe 400 on the inner side thereof, wherein the card groove 302 has the same structure as the card groove 3022041 of the conventional magnetic shoe holder 204;

the magnetic yoke 300 is in a ring structure as shown in fig. 4, the outer periphery of the magnetic yoke is in a non-circular shape due to the anti-slip groove 301 arranged on the outer side, the sleeve 202 is matched with the magnetic yoke 300 as shown in fig. 5, the anti-slip protrusion 2021 is arranged on the inner wall of the sleeve 202 corresponding to the anti-slip groove 301, and the magnetic yoke 300 and the sleeve 202 can be effectively prevented from rotating relatively in the sleeve 202 due to the matching of the anti-slip groove 301 and the sleeve 202, so that the magnetic yoke 300 and the impeller 200 can be ensured to rotate at an equal angular speed, and the rotation speed difference is avoided;

moreover, the anti-slip groove 301 should preferably adopt a trapezoidal groove or a rounded triangular groove, the embodiment specifically adopts the rounded triangular groove, the bottom of the rounded triangular groove is opened outwards along the radial direction, and when the anti-slip groove 301 structure is adopted, the inner wall of the sleeve 202 and the anti-slip bump 2021 matched with the inner wall of the sleeve 202 can effectively improve the rigidity of the sleeve 202, so that the anti-slip effect is realized, the structure of the sleeve 202 is better strengthened, the structural rigidity of the sleeve 202 is improved, and the concentricity of the magnetic structure, the rotor shaft 100 and the impeller 200 is higher;

in the conventional outer rotor structure as shown in fig. 2, the rotor shaft 100 is matched with the blade 201 outside the impeller 200 by the insert 500, at this time, the concentricity of the impeller 200 and the rotor shaft 100 is easily decreased by the additional installation of the insert 500, so that the unbalance thereof is increased, and a steel ring sleeve 203 is further required to be arranged on the sleeve 202, the specific arrangement of the steel ring sleeve 203 is shown in fig. 6, a cylindrical structure is formed by a plurality of arc-shaped plate bodies attached to the inner wall of the sleeve 202, and a plurality of magnetic shoe retainers 204 for fixing the magnetic shoes 400 are required to be arranged inside the sleeve, and the magnetic shoe retainers 204 are also of an assembly type structure, and the reason for adopting the arrangement mode is that the impeller 200 in the conventional outer rotor structure is usually made of aluminum metal material, so that the impeller has a large expansion coefficient, and the magnetic shoe retainers 204 inside are easily loosened and fall off and the rotor shaft 100 slips along with the heating of the outer rotor in the working process, the steel ring sleeve 203 needs to be fixedly connected with the inner wall of the sleeve 202 of the impeller 200 in an adhesive mode and the like, but the arrangement of the steel ring sleeve 203 and the magnetic shoe retainer 204 further increases the problems of poor concentricity, large unbalance amount and the like of the whole structure;

but the utility model sets up through the integral yoke 300 of the special structure, make the concentricity of the whole yoke 300 and rotor shaft 100, impeller 200 get guaranteed at first, through structural improvement and reduction of the part, promote the concentricity of the rotor shaft 100, impeller 200 and yoke 300 while guaranteeing the assembly stability, reduce the amount of unbalance, in addition, the yoke 300 structure and form cooperating with bush 202 used in the utility model, make the bush 202 part of impeller 200 produce certain thermal expansion, difficult to form and separate, because its antiskid projection 2021 will expand correspondingly, make antiskid projection 2021 and antiskid groove 301 can cooperate the joint each other too;

therefore, the structure matching can effectively overcome the problems of poor concentricity and large unbalance amount of the outer rotor of the existing brushless motor, and simultaneously ensures the stability of each structure.

Further, in the above-mentioned case,

in order to further ensure that the concentricity of the impeller 200, the rotor shaft 100 and the magnetic yoke 300 is not gradually reduced due to the thermal expansion problem of the integral outer rotor structure in the working process, the impeller 200, the magnetic yoke 300 and the rotor shaft 100 are made of plastic materials with low thermal expansion coefficients, specifically,

the rotor shaft 100, the magnetic yoke 300 and the impeller 200 can be prepared by adopting common organic materials such as PE, PPR, PP, PVC, PPS and the like to carry out integrated molding or hot injection molding, and the rotor shaft 100, the impeller 200 and the magnetic yoke 300 which are made of R-4-270NA engineering plastics (PPS) are specifically adopted in the embodiment;

by selecting specific materials, the traditional metallic rotor shaft 100, the impeller 200 and the magnetic yoke 300 formed by the steel ring sleeve 203 and the magnetic shoe retainer 204 are replaced, the problems of vibration, looseness, falling and the like caused by thermal expansion in the working process of the outer rotor structure can be greatly avoided, meanwhile, compared with the metallic structure, the aluminum impeller 200 is prepared by adopting a plastic material and has the advantage of lower processing cost, the traditional aluminum impeller 200 is generally processed by multiple steps of processes such as die casting, shot blasting, lathe and the like, the multiple steps of processes are easy to cause the eccentricity of a blank and the center of an inner hole, the defects of uneven density and the like caused by impurities such as air holes or iron slag and the like in aluminum die casting are overcome, the steel ring sleeve 203 is processed by a thin-wall seamless steel pipe, and the wire round is easily formed in the processing process due to the thin wall thickness, the wall thickness is uneven, and finally the rotor is easy to cause unbalance, the magnetic shoe holder 204 is punched from a stainless steel sheet and then rolled to fix the magnetic shoe 400. The magnetic shoe holder 204 is installed in the steel ring sleeve 203, and there may be wire circles in the inner hole of the steel ring sleeve 203, which causes the magnetic shoe 400 to be eccentric, resulting in the unbalance of the rotor, and the assembling sequence is generally: pressing an aluminum blade 201 into the rotor shaft 100, pressing an aluminum blade 201 into the steel ring sleeve 203, installing a magnetic shoe retainer 204, and installing a magnetic shoe 400;

in the 4 steps of the process, the whole assembly body is unbalanced due to the non-concentricity or unbalance of each step or each component, so that the motor shakes, the whole motor is damaged due to the failure of any component, and the structure of the metal material, the punching and press-fitting processes need to apply larger acting force, so that the deformation of any position of the metal part in the assembling process can also cause serious results;

through structural improvement, the assembly difficulty is reduced, the assembly simplicity is improved, the material is further improved, the brushless motor outer rotor can be assembled more conveniently and efficiently, the processing difficulty of each device is reduced, the processing cost is obviously reduced, and only appropriate high-strength plastics such as common plastic impeller 200 materials are selected, so that the performance requirements of the brushless motor outer rotor can be met;

in addition, the metal material easily causes unbalance of the whole assembly body in the assembly process, mainly caused by that the metal reaches the yield limit and permanent deformation, while the plastic material is not easy to generate yield deformation essentially, and each selected material generally has good elastic performance and larger elastic deformation limit deformation, so that stamping and press mounting can be carried out more quickly and effectively in the assembly process without worrying about that the material reaches the yield limit, and effective interference fit installation is facilitated.

Claims (8)

1. An outer rotor structure of a brushless motor, comprising:

the rotor comprises a rotor shaft, an impeller and a magnetic structure;

the impeller is sleeved on the rotor shaft, and an anti-skid structure is arranged at the sleeved position of the impeller and the rotor shaft;

the anti-skid structure comprises a radial anti-skid structure and an axial anti-skid structure;

the impeller comprises fan blades and a sleeve extending along the axial direction of the rotor shaft;

the magnetic structure comprises a magnetic yoke and a magnetic shoe;

the magnet yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve.

2. The external rotor structure of brushless motor according to claim 1,

the magnetic yoke is of an annular structure and is fixedly connected with the inner wall of the sleeve in an anti-slip matching manner.

3. The external rotor structure of brushless motor according to claim 1,

the radial anti-slip structure is a knurling arranged on the outer surface of the rotor shaft;

the axial anti-slip structure is a cutting groove arranged on the outer surface of the rotor shaft.

4. The external rotor structure of brushless motor according to claim 3,

the knurls are straight knurls;

the cutting groove is an annular inwards-sunk cutting groove.

5. The external rotor structure of brushless motor according to claim 2, 3 or 4,

the axial anti-slip structure is axially arranged at two ends of the radial anti-slip structure along the rotor shaft.

6. The external rotor structure of brushless motor according to claim 1,

the magnetic yoke is provided with an anti-slip groove on the outer side, and the inner wall of the sleeve is correspondingly provided with an anti-slip bulge matched with the anti-slip groove to form anti-slip matching of the magnetic yoke and the inner wall of the sleeve.

7. The external rotor structure of brushless motor according to claim 6,

the anti-skid groove is a trapezoidal groove or a rounded triangular groove.

8. The external rotor structure of brushless motor according to claim 1,

the rotor shaft is a plastic rotor shaft;

the impeller is a plastic impeller;

the magnetic yoke is a plastic magnetic yoke.

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