CN114285201B - Brushless motor outer rotor structure and surface treatment method thereof - Google Patents
Brushless motor outer rotor structure and surface treatment method thereof Download PDFInfo
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- CN114285201B CN114285201B CN202111473179.9A CN202111473179A CN114285201B CN 114285201 B CN114285201 B CN 114285201B CN 202111473179 A CN202111473179 A CN 202111473179A CN 114285201 B CN114285201 B CN 114285201B
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Abstract
The invention belongs to the field of brushless motors, and particularly relates to an outer rotor structure of a brushless motor and a surface treatment method thereof. It includes: 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 magnetic yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve; the magnet yoke is of an annular structure and is matched with the inner wall of the sleeve in an anti-slip manner. The invention 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
Technical Field
The invention belongs to the field of brushless motors, and particularly relates to an outer rotor structure of a brushless motor and a surface treatment method thereof.
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 a motor magnet 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 magnetic yoke 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, the motor magnetic yoke and the rotor shaft 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 can not be used seriously.
In addition, the outer rotor structure of the existing brushless motor usually adopts metal materials, the metal materials generally have large thermal expansion coefficient, and the outer rotor structure generates heat to cause the structure to loose and generate vibration or even loose and fall off in the using process.
Therefore, how to improve the structure of the outer rotor of the brushless motor from various aspects such as structure, material and the like, and improve the structural concentricity, and further improve the structural stability and the working stability of the brushless motor is a hot point of research.
Disclosure of Invention
The invention provides a brushless motor outer rotor structure and a method for further performing surface treatment on the brushless motor outer rotor structure, aiming at solving the problems that the structural stability of the existing brushless motor outer rotor is poor, the structural unbalance is large due to the fact that structural components are complicated, the assembly process of the existing brushless motor outer rotor is easy to generate different degrees of non-concentricity, the motion stability is poor due to material factors in the actual use process, and the like.
The invention aims to:
1. the stability of the outer rotor structure is improved;
2. the assembly process of the outer rotor structure is simplified, and the concentricity of the outer rotor structure is improved;
3. the structural stability of the outer rotor structure in the running and using process is improved;
4. the plastic outer rotor structure can be effectively suitable for low-temperature environments.
In order to achieve the purpose, the invention adopts the following technical scheme.
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 magnetic yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve;
the magnet yoke is of an annular structure and is matched with the inner wall of the sleeve in an anti-slip manner.
As a preference, the first and second liquid crystal compositions are,
the radial anti-skid structure is a straight knurling arranged on the outer surface of the rotor shaft;
the axial anti-slip structure is a cutting groove which is arranged on the outer surface of the rotor shaft and is annularly inwards sunk.
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 and/or the impeller and/or the magnetic yoke are made of plastic materials.
As a preference, the first and second liquid crystal compositions are,
the plastic is PE and/or PPR and/or PP and/or PVC and/or PPS.
A surface treatment method for an outer rotor structure of a brushless motor comprises the following steps:
1) Preparing a phase change coating, wherein the phase change coating contains phase change capsules, the content of the phase change capsules is 5-15 wt%, and a phase change coating carrier contains 1.5-2.0 mol/L tetraethyl silicate;
2) Taking a rotor shaft and/or an impeller and/or a magnetic yoke as a part to be processed, immersing the part to be processed into the phase change coating prepared in the step 1), adjusting the pH value to acidity, standing until the surface of the part to be processed is covered with a uniform deposition layer, taking out and drying to finish surface treatment.
As a preference, the first and second liquid crystal compositions are,
the phase change capsule in the step 1) is a paraffin-silicon dioxide phase change capsule;
the phase-change coating carrier is specifically prepared by mixing alcohol and water to prepare a solvent, adding tetraethyl silicate, and dissolving to form the phase-change coating carrier;
the alcohol content in the solvent is more than or equal to 25 percent of VOL.
As a preference, the first and second liquid crystal compositions are,
step 2) the pH value is 2.5-3.5;
the pH value adjusting process is carried out by adopting a non-oxidizing acid.
In the surface treatment method, the core is to prepare the phase change capsule on the surface of the part to be processed through effective deposition. The Phase change capsules (Phase change microcapsules) are microcapsules formed by coating specific Phase change materials through a special process, when the external temperature changes, phase change can occur to core materials in the microcapsules, the Phase change materials absorb or release a large amount of latent heat, and the temperature of the microcapsules is kept constant, so that the effect of intelligently adjusting the temperature is achieved, and the Phase change microcapsules are novel special materials. However, there have been certain difficulties with the use of phase change capsules. Particularly, how to effectively and uniformly grow the carbon nano-particles on the outer surface of a complex workpiece is a difficulty in processing. The phase change coating which is more suitable for processing complex workpieces is formed through reasonable design and is used for surface treatment of the outer rotor structure. The phase-change material in the phase-change capsule is paraffin, and the shell is a silicon dioxide shell layer formed by tetraethyl silicate.
In a particular phase change coating, it is desirable to carefully control the solvent portion of the carrier to contain at least 25% vol of small alcohol, such as methanol, ethanol, and the like, with the most commonly used commercial absolute ethanol being generally selected. This is mainly because the phase change capsules are usually tested in an aqueous carrier, and relatively obvious granular protrusions are formed, so that the actual deposition load is uneven, and the problem of non-concentricity during component assembly is caused. And research experiments show that the uniformity of the deposition load of the alcohol-water mixed system is remarkably improved along with the addition of the alcohol. And it has been shown through a large number of studies that it is possible to ensure relatively excellent deposition uniformity when the alcohol content by volume is more than 21 vol%, without affecting the concentricity of component assembly, and to ensure the balance of the overall structure, but in actual industrial production processes, it is necessary to further ensure the production stability, so it is assumed that the industrial production process employs a production process in which the amount of alcohol is more than 25 vol% vol, and it is possible to maintain relatively more excellent and stable.
In addition, the addition of the tetraethyl silicate can effectively improve the load stability of the phase-change capsule. Because the shell layer of the phase-change capsule is prepared by the organic silicon compound, and the tetraethyl silicate is used as a common shell raw material, the shell raw material can be added to form a film better to link the surface of a part to be processed of the phase-change capsule to form a stable load, and the shell layer thickness of the phase-change capsule can be effectively improved, so that the phase-change material in the phase-change capsule is not easy to leak, and the material toughness of the supercooling-preventing protective layer is greatly improved. Under the condition that tetraethyl silicate is not added, the phase change capsule can form stable and uniform coating fixation through a conventional viscous solution or other adhesives, but the uniformity of deposition coverage cannot be ensured, and meanwhile, the situation that the supercooling-preventing protective layer cracks in the using process is found, so that the service life of the phase change capsule is shortened. Therefore, the specific selection and addition of tetraethyl silicate is one of the keys to the surface treatment of the present invention.
The invention has the beneficial effects that:
through the structural design who rationalizes for the assembly degree of difficulty of whole external rotor structure descends by a wide margin, can effectively improve the concentricity of impeller, rotor shaft and yoke isotructure 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, and further carries out effectual surface treatment to impeller, rotor shaft and yoke, makes it effectively be applicable to high, low temperature environment.
Drawings
FIG. 1 is a schematic view of the structure 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 invention 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 invention based on these teachings. Furthermore, the embodiments of the present invention described in the following description are generally only a part of the embodiments of the present invention, and not all of the 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, are used in the orientations and positional relationships indicated in the drawings, which are based on the orientation or positional relationship shown in the drawings, and are used for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, 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 interconnected within two elements or in a relationship where two elements interact with each other unless otherwise specifically limited. 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 that knurling is arranged on the outer surface of the radial anti-skid structure or damping processing is carried out to form a damping layer or clamping matching and fixing are carried out, however, for the invention, the embodiment adopts relatively optimal outer surface knurling, specifically straight knurling 101 is adopted for the knurling, and the knurling is 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 carrying out single-structure bidirectional antiskid by adopting a mode of reticulate knurling or clamping matching fixation, the mode of mutually separating bidirectional antiskid structures can avoid the damage of the antiskid structures caused by stress concentration or local concentrated abrasion in the working process of the outer rotor structure, and compared with the traditional outer rotor structure shown in fig. 2, the mode of adopting the matching of 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 firstly to easily increase the unbalance amount of the rotor, and secondly, the rotor shaft 100 and the impeller 200 are usually combined by adopting the modes of interference fit press fitting or stamping, and the addition of the insert 500 can cause the increase of the assembly difficulty and simultaneously has the problem that the insert 500 is easily worn and deformed in the assembly process of the impeller 200, so that 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 slot 302 for mounting the magnetic shoe 400 on the inner side thereof, and the structure of the slot 302 is the same as that of the slot 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 fan 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 reduced due to the addition of the insert 500, so that the unbalance 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 as shown in fig. 6, a plurality of arc-shaped plate bodies are attached to the inner wall of the sleeve 202 to form a cylindrical structure, a plurality of magnetic shoe retainers 204 for fixing the magnetic shoes 400 are required to be arranged in the cylindrical structure, and the magnetic shoe retainers 204 are also in 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, the magnetic shoe retainers 204 inside are easily loosened and fall off along with the heating of the outer rotor during the working process, and the rotor shaft 100 slips, and the steel ring sleeve 203 is required to be fixedly connected to the inner wall of the sleeve 200 by means such as adhesion, but the arrangement of the steel ring 203 and the steel ring retainers 204 further increase the integral eccentricity and the problem of the unbalance and the integral structure, and the integral structure of the unbalance;
however, the arrangement of the integrated magnetic yoke 300 with a special structure ensures the concentricity of the integrated magnetic yoke 300, the rotor shaft 100 and the impeller 200, ensures the assembly stability and simultaneously improves the concentricity of the rotor shaft 100, the impeller 200 and the magnetic yoke 300 and reduces the unbalance amount by improving the structure and reducing the number of parts, and in addition, the structure of the magnetic yoke 300 and the form of matching with the sleeve 202 used by the invention ensure that the sleeve 202 part of the impeller 200 is difficult to separate even if thermal expansion of a certain degree occurs, and because the anti-skid protrusions 2021 can also expand correspondingly, the anti-skid protrusions 2021 and the anti-skid grooves 301 can also be matched and clamped with each other;
therefore, the structure matching can effectively overcome the problems of poor concentricity and large unbalance amount of the existing brushless motor outer rotor, 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 metal 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 of an outer rotor structure in the working process can be greatly solved, meanwhile, compared with the metal 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 die casting, shot blasting, lathes and the like, the multiple steps of the process easily cause eccentricity of a blank and the center of an inner hole, the aluminum die casting possibly has the defects of uneven density and the like caused by impurities such as air holes or iron slag, the steel ring sleeve 203 is processed by a thin-wall seamless steel pipe, and due to the thin wall thickness, a wire circle is easily formed in the processing process, the wall thickness is uneven, and finally, the rotor is easily unbalanced, and the magnetic shoe retainer 204 is rolled after being stamped by a stainless steel sheet and is used for fixing 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 a rotor shaft 100, pressing an aluminum blade 201 into a 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.
In a still further aspect of the present invention,
in the practical application process, researchers also find that the outer rotor structure made of the plastic material can basically meet the use environment of the current vast majority, but when the outer rotor structure is used in a very small low-temperature environment, the impeller 200, the rotor shaft 100 and the magnet yoke 300 made of the plastic material are easy to embrittle to a certain degree, and the structural stability, the safety and the like of the whole assembly body are influenced to a certain extent, for example, PPS plastic adopted in the embodiment can usually bear a high-temperature working environment about 240 ℃, but the low-temperature resistance performance of the PPS plastic is very effective, the PPS plastic works in a low-temperature environment of-30 to-5 ℃, and particularly the structural brittle failure is easy to occur when the PPS plastic is started to work;
therefore, it is necessary to provide good low temperature resistance by further surface treatment of the molded rotor shaft 100, impeller 200 and yoke 300;
specifically, a phase change coating is used for forming a supercooling-prevention protective layer on the surfaces of a rotor shaft 100, an impeller 200 and a magnet yoke 300 which are made of PPS materials in a coating and curing mode;
the phase change coating specifically comprises the following components:
dispersing a paraffin-silica phase change capsule material with paraffin coated by silica into a silicon-containing solvent carrier, controlling the content of phase change capsules to be 5-15 wt%, the content of phase change capsules in the embodiment to be 12wt%, and the embodiment of the silicon-containing solvent carrier is specifically a mixed solution of tetraethyl silicate, ethanol and deionized water, wherein the content of ethanol in the solvent is required to be more than or equal to 25 vol%, the ethanol and the deionized water in the embodiment are mixed in a volume ratio of 1: 3 to serve as the solvent, in addition, the molar concentration of tetraethyl silicate in the solvent carrier after tetraethyl silicate is added is 1.5-2.0 mol/L, the molar concentration of tetraethyl silicate in the embodiment is 1.65mol/L, and the prepared phase change coating needs to be stored at 20-40 ℃ and used as early as possible;
the phase change capsules are available from BASF corporation;
when preparing the super-cooling protective layer:
immersing the parts to be processed (such as the rotor shaft 100, the impeller 200 and the magnet yoke 300) in the phase-change coating, vacuumizing to 0.1atm, keeping for 10min, slowly adding industrial hydrochloric acid to adjust the pH value to 2.5, standing for 3d, taking out the parts to be processed after the surfaces of the parts to be processed are covered with uniform white deposition layers, and placing at 60 ℃ for hot drying for 3d to finish the preparation of the super-cooling protective layer on the outer surfaces of the parts such as the rotor shaft 100, the impeller 200 and the magnet yoke 300;
by the preparation method, the silicon-phase change capsule supercooling protective layer can be formed on the surface of the part to be processed, so that the integral plastic outer rotor structure can bear higher working temperature.
After the rotor shaft is made of PPS (polyphenylene sulfide) plastic (R-4-270 NA engineering plastic), the rotor shaft normally works within a temperature range of 0-60 ℃, the structure and the connection stability of each part can be kept, and the rotor shaft has a good use effect, but the impeller 200 and the rotating shaft are very easy to brittle fracture under the conditions that the temperature is-30-5 ℃ and particularly is not higher than 18 ℃, for example, after the rotor shaft is stopped and kept for 7 days in a-20 ℃ environment, the fracture rate of the impeller 200 reaches 9.4% (32 tests) when the rotor shaft is started at the rotating speed of 2600R/min, and the fracture rate of the rotor shaft 100 reaches 6.3% (32 tests);
after the anti-supercooling protective layer is prepared, a low-temperature running test of the outer rotor structure of the brushless motor is carried out, after the test, the rotor is stopped and kept at the temperature of minus 30 ℃ for 7 days, the breakage rate of the impeller 200 is 3 percent (32 times of test) when the rotor is started at the rotating speed of 2600r/min, no material brittle failure occurs on the rotor shaft 100 breakage rate and the magnet yoke 300 breakage rate, and the rotor is stopped and kept at the temperature of minus 20 ℃ for 7 days and then is started at the rotating speed of 2600r/min, and no material brittle failure occurs;
it can be seen from the above comparison that, by the arrangement of the supercooling-preventing protective layer, the low-temperature resistance of the plastic brushless motor outer rotor structure can be enhanced remarkably, and the phase change coating has good leveling property, so that the concentricity of the impeller 200, the rotor shaft 100 and the magnetic yoke 300 is not affected in the preparation process.
In addition, the surface treatment process is also generally applied to the conventional aluminum outer rotor structure, and because the supercooling-preventing protective layer formed by the surface treatment process also has a certain overheating-preventing effect, the thermal expansion effect of the aluminum outer rotor structure can be inhibited by reducing the temperature change of the surface part of the aluminum outer rotor structure.
Claims (4)
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 magnetic yoke is provided with a clamping groove for assembling the magnetic shoe and is fixedly arranged in the sleeve;
the magnetic yoke is of an annular structure and is matched with the inner wall of the sleeve in an anti-slip manner;
the radial anti-skidding structure is straight knurling arranged on the outer surface of the rotor shaft;
the axial anti-slip structure is a cutting groove which is arranged on the outer surface of the rotor shaft and is annularly inwards sunk;
the axial anti-skid structures are arranged at two ends of the radial anti-skid structure along the axial direction of the rotor shaft;
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 of the magnetic yoke and the inner wall of the sleeve;
the anti-skid groove is a trapezoidal groove or a rounded triangular groove;
the rotor shaft and/or the impeller and/or the magnet yoke are made of plastic;
the plastic is PE and/or PPR and/or PP and/or PVC and/or PPS.
2. A surface treatment method of an outer rotor structure of a brushless motor according to claim 1,
the method comprises the following steps:
1) Preparing a phase change coating, wherein the phase change coating contains phase change capsules, the content of the phase change capsules is 5-15 wt%, and a phase change coating carrier contains 1.5-2.0 mol/L tetraethyl silicate;
2) Taking a rotor shaft and/or an impeller and/or a magnetic yoke as a part to be processed, immersing the part to be processed into the phase change coating prepared in the step 1), adjusting the pH value to acidity, standing until the surface of the part to be processed is covered with a uniform deposition layer, taking out and drying to finish surface treatment.
3. A surface treatment method of an outer rotor structure of a brushless motor according to claim 2, wherein,
the phase change capsule in the step 1) is a paraffin-silicon dioxide phase change capsule;
the phase-change coating carrier is specifically prepared by mixing alcohol and water to prepare a solvent, adding tetraethyl silicate, and dissolving to form the phase-change coating carrier;
the content of alcohol in the solvent is more than or equal to 25 percent VOL.
4. A surface treatment method of an outer rotor structure of a brushless motor according to claim 2, wherein,
step 2) the pH value is 2.5-3.5;
the pH value adjusting process is carried out by adopting non-oxidizing acid.
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| CN202111473179.9A CN114285201B (en) | 2021-12-03 | 2021-12-03 | Brushless motor outer rotor structure and surface treatment method thereof |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07245926A (en) * | 1994-03-08 | 1995-09-19 | Mitsubishi Electric Corp | Brushless motor |
| WO2012119284A1 (en) * | 2011-03-09 | 2012-09-13 | 上海航天汽车机电股份有限公司 | Outer rotor of brushless motor and manufacturing method thereof |
| CN204597662U (en) * | 2015-03-18 | 2015-08-26 | 佛山市顺德区志尚电器有限公司 | A kind of all-in-one-piece permanent-magnet brushless DC electric machine rotor |
| CN210444130U (en) * | 2019-09-27 | 2020-05-01 | 深圳拓邦股份有限公司 | Hair drier and direct current motor with fan blades |
| CN112398278A (en) * | 2020-12-03 | 2021-02-23 | 江苏苏美达五金工具有限公司 | Novel axial-flow heat dissipation system of outer rotor permanent magnet brushless motor |
| CN112838728A (en) * | 2020-12-30 | 2021-05-25 | 顺丰科技有限公司 | Birotor permanent magnet synchronous motor and working method thereof |
-
2021
- 2021-12-03 CN CN202111473179.9A patent/CN114285201B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07245926A (en) * | 1994-03-08 | 1995-09-19 | Mitsubishi Electric Corp | Brushless motor |
| WO2012119284A1 (en) * | 2011-03-09 | 2012-09-13 | 上海航天汽车机电股份有限公司 | Outer rotor of brushless motor and manufacturing method thereof |
| CN204597662U (en) * | 2015-03-18 | 2015-08-26 | 佛山市顺德区志尚电器有限公司 | A kind of all-in-one-piece permanent-magnet brushless DC electric machine rotor |
| CN210444130U (en) * | 2019-09-27 | 2020-05-01 | 深圳拓邦股份有限公司 | Hair drier and direct current motor with fan blades |
| CN112398278A (en) * | 2020-12-03 | 2021-02-23 | 江苏苏美达五金工具有限公司 | Novel axial-flow heat dissipation system of outer rotor permanent magnet brushless motor |
| CN112838728A (en) * | 2020-12-30 | 2021-05-25 | 顺丰科技有限公司 | Birotor permanent magnet synchronous motor and working method thereof |
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| CN114285201A (en) | 2022-04-05 |
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