CN113872373A - Miniature DC motor - Google Patents
Miniature DC motor Download PDFInfo
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- CN113872373A CN113872373A CN202111222567.XA CN202111222567A CN113872373A CN 113872373 A CN113872373 A CN 113872373A CN 202111222567 A CN202111222567 A CN 202111222567A CN 113872373 A CN113872373 A CN 113872373A
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- brush
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Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/14—Means for supporting or protecting brushes or brush holders
- H02K5/143—Means for supporting or protecting brushes or brush holders for cooperation with commutators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
- H02K11/02—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for suppression of electromagnetic interference
- H02K11/026—Suppressors associated with brushes, brush holders or their supports
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation
- H02K13/10—Arrangements of brushes or commutators specially adapted for improving commutation
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
- H02K5/163—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields radially supporting the rotary shaft at only one end of the rotor
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Motor Or Generator Frames (AREA)
- Dc Machiner (AREA)
Abstract
The invention provides a miniature direct current motor, which comprises a motor device and a filter device, wherein the motor device comprises a motor shaft and a motor shaft; the motor device comprises a cover plate assembly, a stator assembly and a rotor assembly capable of rotating relative to the stator assembly; the cover plate assembly comprises at least one electric brush, an electric brush terminal and a cover plate bearing; the material of the electric brush is Agpd50, and the brush sheet is reinforced; the material of the brush terminal is selected from copper and tin; the cover plate bearing is made of stainless steel; the filtering device is electrically connected with an electric brush terminal in the cover plate assembly and comprises a PCB circuit board and a filter, and the PCB circuit board is fixed on the cover plate assembly and is electrically connected with the electric brush terminal; the filtering device is used for inhibiting differential mode and common mode noises and preventing electromagnetic disturbance signals from being input into the motor through conduction. The invention combines the micro direct current motor and the filter device together for use, eliminates or weakens the noise caused by the disturbance signal which is conducted and input to the motor by the power supply, prevents the noise from diffusing outwards and reduces the interference.
Description
Technical Field
The invention relates to the technical field of motors, in particular to a miniature direct current motor.
Background
With the continuous expansion of the use field of the micro motor, the use environment of the micro motor is more and more complex. The environments of high temperature, humidity, corrosive gas, dust, high load and the like often blacken the palladium layer of the electric brush, blacken the bearing of the bearing cover plate of the shell, oxidize the commutator, rust the terminals of the electric brush and swell the magnetic stripe, thus seriously affecting the working state and the service life of the micromotor. Therefore, the development and production of the miniature motor with high performance of abrasion resistance, oxidation resistance, corrosion resistance and arc resistance can be widely applied to complex environments, the service life of the motor is prolonged, the development theme of the micro-motor industry is realized, and the responsibility of each designer and producer is also realized.
As a core element of the micro-machine, the brush and the commutator and the cooperation of the two have a crucial influence on the working stability and the service life of the micro-machine. Failures due to various internal and external factors during use of a micro-machine are most often manifested in the form of brush and commutator damage.
The loads to which the brushes and commutator are subjected are mainly sliding friction under the action of the current, the damage forms of which are mainly severe wear and arc erosion. The miniaturization of the micromotor is developed, the heat dissipation condition is correspondingly poor, and the temperature rise of the working surface of the electric brush is increased due to the requirement of high rotating speed. The working area of the brush is concentrated on a small section of the precious metal surface, and the abrasion condition of the brush is far worse than that of the commutator. When the noble metal layer of the electric brush is worn out, the exposed copper alloy base band has large resistance, high temperature, weak oxidation resistance, further increased abrasion speed and stronger electric arc, thereby accelerating the failure of the motor. Sometimes the brushes are worn away even before the commutator precious metal layer wears out.
When the brush contacts with the commutator, the brush looks like smooth surface contact, the actual contact surface is uneven, and the point contact formed by the dispersed convex parts is used for carrying the current conduction task. In contact, the softer metal is torn off and transferred to the surface of the harder metal, creating adhesive wear, and the scraped metal particles are transferred in other directions, creating wear. If the scraped metal powder is accumulated on the brush surface to form a needle-like structure, it is hard and sharp, and the scraping process is further accelerated. The metal powder is filled in grooves between commutator slip rings to cause short circuit, which affects the normal operation of the micro motor and even causes 'dead halt'. Due to excessive abrasion, the precious metal compound layer on the surface of the commutator is scraped quickly, so that the base material is exposed, the contact resistance is increased sharply, the running speed of the motor is unstable, and the falling speed occurs.
In addition to carrying longitudinal currents during operation of the commutator, there is the task of commutating currents in the short-circuited armature coil, these currents being the reverse currents and reactive voltages generated when the main current is commutated, causing edge sparks and arcing when the brushes slide over the commutator surface. Under the action of electric arc, nitrogen oxide is produced and reacts with air to generate nitric acid, so that the corrosion phenomenon generated on the surface of the commutator can cause the increase of contact resistance, and the stability and the service life of the motor are seriously influenced.
In the air there is H2S、SO2And AgS is generated on the surface of the Ag alloy of the commutator and is transferred to the periphery along with the time, so that the continuous corrosion of commutator materials is caused, and the inter-pole short circuit is possibly caused, and the running stability of the motor is damaged.
In the rotation process of the micro motor, the electric brush continuously draws electric arc, and the electric arc generates high-frequency noise. High frequency noise radiates out through the motor leads and the housing gap. The metal shell of the motor can reflect and absorb internal radiation noise. The noise is shielded from radiating outwards. However, much of the radiated noise is radiated through the motor leads, which not only causes the noise to seriously affect the performance degradation of the motor and the electrical system, but also affects the service life of the motor and the electrical system.
The existing miniature direct current motor is usually made of AgCuRe alloy material selected from commutator material, the electric brush material is AgPb30, the electric brush terminal material is tin-plated iron, and the magnetic ring is plastic magnet. In a complex working environment (particularly in a sublimed sulfur, salt mist and gasoline environment), parts of the motor are seriously oxidized, a palladium layer of an electric brush is blackened, a bearing of a bearing cover plate of a shell is blackened, a commutator is oxidized, an electric brush terminal is rusted, and a magnetic stripe is swelled, so that the requirements of a user cannot be met.
However, the prior art still has insufficient recognition of the problem, and related solutions are rarely proposed. As a solution expert for micro motors, the industry including the applicant is always exploring solutions.
For example, chinese patent document CN205377530U proposes a commutator cover of a standard motor, which includes a plastic housing, a metal connecting sheet, a circuit board and a carbon brush, wherein the fixing is realized by the elasticity of the metal connecting sheet, and the small-sized filter circuit board is fixed by using the spring pressure, so as to reduce the welding process and alleviate the problems of abrasion, blackening and the like. However, since there is essentially no improvement in the structure and material of the inherent motor, the effect is not very significant, and disadvantages such as generation of loud noise due to vibration of the reed, rusting of the brush terminal is still very easy, and the like are apparent.
For example, chinese patent document CN103022847A describes an electric brush for dc traction motor, which includes two carbon brushes, four copper soft braided wires and a triangular spacer, and by matching them, the split two carbon brushes are separated to make them move completely independently, so that the surface temperature rise of the commutator and the temperature rise of the electric brush are not increased continuously, and the life of the electric brush is maintained. The technical scheme can effectively relieve the phenomenon of brush blackening, however, the structure is complex, the generation of electric arcs is additionally increased by an additional electric connection structure, and although the electric arcs can be restrained within an allowable range, the energy consumption is still additionally increased.
For example, chinese patent document CN1069150A describes a micro dc motor, which is designed to prevent the generation of black substances due to the chemical reaction between harmful gases generated by electric sparks and heat and the material of the elements, by isolating the internal space of the motor or the internal space of the motor itself from the atmosphere outside the motor. In the scheme, the motor needs to be isolated from the external atmosphere, so that the process precision requirement is extremely high, the airtight structure of the internal space of the motor is ensured, and the cost is greatly increased.
Therefore, a micro dc motor with high wear resistance, oxidation resistance, corrosion resistance, arc resistance, wide adaptability to complex environments, long service life and low cost is needed only by selecting materials and changing the structure.
Disclosure of Invention
In view of the above problems, the present invention aims to provide a micro dc motor which can enhance the working stability of the motor, has the characteristics of wear resistance, temperature resistance, corrosion resistance and arc resistance in a complex environment, prolongs the service life of the motor, and reduces the production cost.
The invention provides a miniature direct current motor, which comprises a motor device and a filter device, wherein the motor device comprises a motor shaft and a motor shaft;
the motor device comprises a cover plate assembly, a stator assembly and a rotor assembly capable of rotating relative to the stator assembly; the cover plate assembly comprises at least one electric brush, an electric brush terminal and a cover plate bearing; the brush material is Agpd50, and ribs are arranged on the surfaces of the brush pieces along the length extension direction of the brush pieces so as to increase the contact points between the brush and a commutator of the rotor assembly; the material of the brush terminal is selected from copper and tin; the cover plate bearing is made of stainless steel;
the filtering device is electrically connected with an electric brush terminal in the cover plate assembly, the filtering device comprises a PCB circuit board and a filter, and the PCB circuit board is fixed on the cover plate assembly and is electrically connected with the electric brush terminal; the filtering device is used for inhibiting differential mode and common mode noises and preventing electromagnetic disturbance signals from being input into the motor through conduction.
Optionally, the Agpd50 has a pd content of 50% and a tensile strength of 347N/mm2And the hardness of the finished composite layer is HV 200.
Optionally, the filter employs a BDL filter.
Optionally, the PBC board has 2 input points, 2 output points, and 4 ground points.
Optionally, the stator assembly comprises a casing, a bearing, and a magnetic strip; a main shaft through hole is formed in the center of the bottom of the machine shell, the bearing is pressed into the main shaft through hole in the bottom of the machine shell, and the magnetic strip is pressed into the inner wall of the machine shell;
wherein, the casing chooses stainless steel material for use.
Optionally, the micro dc motor further comprises a conductive device;
the conducting device comprises a conducting strip, one end of the conducting strip is welded with the grounding point of the PCB, and the other end of the conducting strip is welded on the periphery of the shell.
Optionally, the rotor assembly comprises an insulation sheet, a silicon steel sheet, an output shaft, a sleeve, a coil winding, a commutator, a piezoresistor and an oil baffle; the output shaft is assembled in the central hole of the silicon steel sheet, and the sleeve is sleeved in the output shaft;
the silicon steel sheet is provided with the insulating sheet; the commutator is sleeved at the shell end of the output shaft; the coil winding is wound on the silicon steel sheet through the commutator leg; the piezoresistor is welded with the leg of the commutator and is pressed on the coil winding; the oil baffle plate is sleeved on the output shaft and pressed on the commutator.
Optionally, the commutator adopts a gold plating process and is polished and oiled; the commutator is provided with an Ag alloy surface, the Ag alloy surface is coated with an Au layer, the thickness of the Au layer is less than 0.2 mu m, and the Ag alloy is protected from being corroded by sulfur-containing air.
Optionally, the cover plate assembly further comprises a cover plate, a middle plate, a brush a and a brush B;
the cover plate is provided with a central hole, and the cover plate bearing is pressed in the central hole of the cover plate; the middle plate is pressed on the cover plate, and a foot rest of the electric brush is embedded in the positioning groove of the middle plate and transversely arranged on the inner side of the middle plate.
The invention provides an abrasion-resistant corrosion-resistant low-noise micro direct current motor, which can enhance abrasion resistance and corrosion resistance of the motor, enhance electromagnetic compatibility, reduce electromagnetic interference and eliminate or weaken disturbance signals transmitted and input to the motor by a power supply, thereby eliminating electromagnetic noise, improving the function and the service life of the motor.
Drawings
Fig. 1 is a perspective view showing a basic structure of a micro dc motor according to an embodiment of the present invention;
fig. 2 is a perspective view illustrating a stator assembly of a micro dc motor according to an embodiment of the present invention;
fig. 3 is a perspective view illustrating a rotor assembly of a micro dc motor according to an embodiment of the present invention;
fig. 4 is a perspective view illustrating a cover plate assembly of a micro dc motor according to an embodiment of the present invention;
FIG. 5 is another perspective view of the cover plate assembly of the micro DC motor according to an embodiment of the present invention;
fig. 6 is a perspective view showing a filter device of a micro dc motor according to an embodiment of the present invention;
fig. 7 is a schematic view illustrating installation of a conductive strip in a conductive device of a micro dc motor according to an embodiment of the present invention;
fig. 8 is a schematic diagram illustrating brush reinforcement of a micro dc motor according to an embodiment of the present invention.
Wherein, 1-stator component, 2-machine shell, 3-bearing, 4-magnetic strip; 5-rotor assembly, 6-insulating sheet, 7-silicon steel sheet, 8-output shaft, 9-set pipeline, 10-coil winding, 11-commutator, 12-piezoresistor and 13-oil baffle; 14-cover assembly, 15-cover, 16-middle plate, 17-brush a17, 18-brush B18, 19-cover bearing, 20-brush terminal; 21-filtering device, 22-PCB circuit board, 23-grounding point, 24-filter, 25-input contact, 26-output contact; 27-conductive strip.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making 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 "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description of the present invention, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.
As can be seen from fig. 1 to 7, the micro dc motor according to an embodiment of the present invention may include a motor device and a filter device 21 (see fig. 6). The electric machine arrangement comprises, among other things, a cover plate assembly 14 (fig. 4), a stator assembly 1 (fig. 2), and a rotor assembly 5 (fig. 3) rotatable relative to the stator assembly 1. The cover assembly 14 includes at least one brush (in this embodiment, brushes A-17 and B-18), brush terminal 20, and cover bearing 19; the material of the electric brush is Agpd 50; the material of the brush terminal 20 is selected from copper and tin; the cover plate bearing 19 is made of stainless steel. The filter device 21 is electrically connected with the brush terminal 20 in the cover plate assembly 14, the filter device 21 comprises a PCB circuit board and a filter 24, the PCB circuit board is fixed on the cover plate assembly 14 and is electrically connected with the brush terminal 20; the filter device 21 is used for suppressing differential mode and common mode noise and preventing electromagnetic disturbance signals from being input into the motor through conduction.
According to the micro direct current motor provided by the embodiment, the micro direct current motor and the filter device 21 are combined together for use, so that the abrasion resistance and corrosion resistance of the motor can be enhanced, the electromagnetic compatibility can be enhanced, the electromagnetic interference is reduced, and a disturbance signal transmitted and input to the motor by a power supply is eliminated or weakened, so that the electromagnetic noise is eliminated, the function of the motor is improved, and the service life of the motor is prolonged.
As shown in fig. 2, the stator assembly 1 of the micro dc motor in this embodiment includes a casing 2, a bearing 3, and a magnetic strip 4; a main shaft through hole is formed in the center of the bottom of the machine shell 2, the bearing 3 is pressed into the main shaft through hole in the bottom of the machine shell 2, and the magnetic strip 4 is pressed into the inner wall of the machine shell 2; wherein, the casing 2 is made of stainless steel. The magnetic material selected by the magnetic stripe 4 may be a ferrite magnetic ring. The ferrite magnetism is stronger than plastic magnetism, the concentricity and the quality of the magnetic ring are uniform, a fixed magnetic field is generated, the working capacity of the motor is improved, the working temperature is-40-200 ℃, and the plastic magnetism which is 10-60 ℃ higher than the working temperature can adapt to more complex temperature environment. Meanwhile, the ferrite magnetic ring has a good inhibition effect on high-frequency noise.
As shown in fig. 3, the rotor assembly 5 of the micro dc motor in this embodiment includes an insulation sheet 6, a silicon steel sheet 7, an output shaft 8, a sleeve 9, a coil winding 10, a commutator 11, a varistor 12, and an oil baffle 13; wherein, the output shaft 8 is assembled in the central hole of the silicon steel sheet 7, and the sleeve 9 is sleeved in the output shaft 8; the silicon steel sheet 7 is provided with an insulating sheet 6; the commutator 11 is sleeved in the end of the output shaft 8 casing 2; the coil winding 10 is wound on the silicon steel sheet 7 through a leg of the commutator 11; the piezoresistor 12 is welded with the leg of the commutator 11 and pressed on the coil winding 10; the oil baffle 13 is sleeved on the output shaft 8 and pressed on the commutator 11. The commutator 11 adopts gold plating technique and is polished and oiled; the commutator 11 has an Ag alloy surface coated with an Au layer, the thickness of the Au layer is less than 0.2 μm, and the Ag alloy is protected from corrosion of sulfur-containing air.
The miniature direct current motor that this embodiment provided, for preventing 11 surperficial noble metal multiple layers of commutator from scraping, cause the naked dew of matrix material, contact resistance sharply risees, makes motor functioning speed unstable, the speed that falls appears, and adopts the thin Au layer of Ag alloy surface coating one deck, reinforcing surface hardness, protection Ag alloy does not receive the erosion that contains the air simultaneously, extension motor life improves product reliability. The commutator 11 can also be polished to remove burrs, increase smoothness and reduce sliding wear with the brushes. As shown in fig. 4 to 5, the cover assembly 14 of the micro dc motor in this embodiment may further include a cover plate 15 and a middle plate 16. The cover plate 15 is provided with a central hole, and a cover plate bearing 19 is pressed in the central hole of the cover plate 15; the middle plate 16 presses on the cover plate 15, and the foot rest of the electric brush is embedded in the positioning groove of the middle plate 16 and transversely arranged on the inner side of the middle plate 16. The brush in this embodiment includes a brush a17 and a brush B18, and the foot rests of the brushes a17 and B18 are both embedded in the positioning groove of the middle plate 16 and transversely arranged inside the middle plate 16. In the micro dc motor provided in this embodiment, Agpd50 selected by the brush has a pd content of 50% and a tensile strength of 347N/mm2And the hardness of the finished composite layer is HV 200. Due to the adoption of pd content of 50 percent and tensile strength of 347N/mm2The alloy material of the finished composite layer with the hardness of HV200 enhances the hardness of the electric brush, and the hardness is improved by 40HV compared with Agpd 30. The higher the hardness of the material, the better the wear resistance and corrosion resistance. The brush piece of the electric brush is reinforced, so that the electric brush is contacted with the commutator at the 3 point contact base of the common electric brushThe point contact of 6 points is increased on the basis, and the abrasion of the brush is reduced (as shown in figure 8). Usually, the wear disappearance time of the noble metal layer of the brush is far earlier than that of the noble metal layer of the commutator 11, and when the noble metal layer is exhausted, the wear speed of the brush is further increased, the electric arc is stronger, and the failure of the motor is accelerated. The wear resistance of the Agpd50 alloy is improved, the service life of the electric brush is prolonged, and the performance and the service life are improved. The brush piece of the electric brush is reinforced, electric sparks during reversing are reduced, carbon deposition is reduced, the service life of the motor is prolonged, and the waveform detected by the digital oscilloscope when the motor runs is more stable.
The material of brush terminal 20 can be selected from copper tin plating to enhance conductivity and transmission. The copper material has good conductivity and strong transmission performance. Iron materials have poor electrical conductivity, are prone to generate heat at joints, and can also have poor contact to interrupt signal transmission. Copper is prevented from generating 'verdigris' in a humid environment to increase contact resistance, contact surfaces are overheated, and the copper can be prevented from being oxidized after the surface of the copper is plated with a layer of tin. The tin oxide has good conductivity, and can not cause phenomena such as increase of contact resistance, overheating of contact surfaces and the like. Meanwhile, the tin material is soft, and the contact surface can be ensured to be in close contact with each other when the bolt or the electric wire is connected.
In addition, casing 2 and apron bearing 19 in this embodiment select for use stainless steel material, and stainless steel has extremely strong corrosion resistance, is difficult to rust, can move in liquid, keeps very clean state for a long time, and has very high heat-resisting ability, consequently, stainless steel casing 2 and stainless steel bearing can prevent to take place to corrode and rust, in addition, stainless steel bearing in use does not need oil or lubricating oil protection to can practice thrift the cost.
Alternatively, the filter 24 in the filtering device 21 may be a BDL filter. The BDL filter is composed of A, B multilayer capacitors and shielding electrodes, has all functions of a standard bypass capacitor, is additionally provided with two parallel reference electrodes G1 and G2, and forms a Faraday shielding cage after surrounding and separating the two electrodes of the capacitor, or forms a coaxial line structure mode, and creatively transforms an originally unbalanced single-end assembly into a double-end balanced assembly which is matched with a line-to-ground capacitor, has a compensation effect on temperature and voltage changes and has the same aging effect on the two electrodes, namely the double-end balanced assembly is transformed into a double-end balanced assembly which consists of two capacitors with completely equal nominal values; the structural dimensions of the two electrodes of the capacitor and the reference electrodes G1, G2 follow the 20H design rule, reducing the outward electromagnetic radiation by 70%, and minimizing ESR, ESL. The filtering effect is good, the frequency band is wide, and the cost is low; the number of devices is small, and the process is simple; the surface mounting process reduces the manual welding cost, simplifies the production process and improves the production efficiency.
According to the miniature direct current motor provided by the embodiment of the invention, the BDL filter is adopted, so that common mode noise and differential mode noise are effectively inhibited, system noise conversion is reduced, and the miniature direct current motor is not limited by current. The motor noise is mainly conducted noise and radiated noise. The conducted noise is differential mode noise and common mode noise, and the radiated noise is noise converted from system noise to be radiated outwards. The differential mode noise is generated between power lines, a noise source enters the power lines in series, and the direction of the noise current is the same as that of the power current; the common mode noise is noise in which a noise current leaking through a stray capacitance or the like returns to the power supply line via the ground. The BDL filter has two Y capacitors and an X capacitor, the Y capacitor is connected between the input line and the ground line to eliminate common mode interference, and the X capacitor is connected to two ends of the input line to eliminate differential mode interference. The X2Y capacitance effectively blocks ground current noise and shunt noise to the capacitor A, B electrode and A, B electrode to ground. The electric reflux area is greatly reduced, and the magnetic lines of force generated by the A, B electrode are mutually reduced. To improve the insertion loss performance of the BDL, both ends are grounded (G1, G2 are grounded). The BDL filter in the embodiment is not limited by current, can effectively inhibit common mode noise and differential mode noise, and reduces system noise conversion. The traditional LC filter circuit directly replaces 2-3 filter capacitors of a common-mode inductor, the frequency domain noise suppression reaches 41dBuVZ to the maximum extent, noise conduction and radiation emission are reduced, and the circuit has better temperature and vibration characteristics. The energy micromotor meets the requirement of ultrathin design.
Further, as shown in fig. 6, the PCB board in the filter device 21 may have 2 input points, 2 output points, and 4 grounding points. PCB traces and vias (not shown) are key factors to embody the BDL effect. The line width keeps the width of the AB terminal of the BDL filter, and the grounding through hole is as close to the device end as possible. As shown in fig. 3, the filter device 21 of the present embodiment may further include a grounding point 23, an input contact 25, and an output contact 26. The power line is connected to the input point 25; the brush terminals 20 are soldered to the output contacts 26 to secure the PCB 22 to the outside of the cover 15.
By adopting the PCB 22, the motor is developed to high performance, miniaturization and combination. The ground pin of the BDL filter 24 and the PCB board 22 should be grounded to the metal casing of the motor at multiple points to reduce the ground impedance. The BDL terminals A, B penetrate through the two leads of the motor. The terminals G1, G2 are grounded (the grounding point 23 is the metal casing of the motor for the motor). Connected in a filtering and bypass manner and thus not limited by current. The two leads of the motor should penetrate the BDL filter PCB to prevent radiation noise from bypassing the device. The noise-generated energy will be concentrated in the BDL filter when the leads are penetrated through the PCB, and will not radiate out through the leads. And the multipoint grounding is adopted, so that the earth impedance is reduced, and the filtering effect is more ideal.
In an alternative embodiment of the present invention, the micro dc motor may further include a conductive device; the conductive means comprises a conductive strip 27, one end of the strip 27 is soldered to the grounding point 23 of the PCB board, and the other end is soldered to the periphery of the casing 2.
The embodiment of the invention provides a micro direct current motor which is designed from multiple dimensions, the micro direct current motor for realizing wear resistance, corrosion resistance and low noise is developed in the simplest and most direct mode, an electric brush coating material is AgPb50, a commutator 11 is subjected to a gold plating process and polished and oiled, a tin plate of a brush terminal 20 is changed into a tin plate of copper, a plastic magnetic strip is changed into a ferrite magnetic strip, a shell 2 and a cover plate bearing 19 are changed into stainless steel from a copper base, a filter device 21 is provided with a PCB circuit board 22, a BDL filter is installed, differential mode and common mode noise are inhibited, system noise conversion is reduced, and therefore electromagnetic noise generated by motor operation is eliminated. Further, the brush terminal 20 is made of copper-plated tin, which can reduce the resistance value of the base material and improve the conductivity and terminal flexibility. The miniature direct current motor that this embodiment provided performance is strong, moreover resistance to wears, anticorrosive, anti-arc performance, when effectively reducing electromagnetic interference, eliminating electromagnetic noise, improves the stability and the life-span of motor work.
Claims (10)
1. A miniature direct current motor is characterized by comprising a motor device and a filter device;
the motor device comprises a cover plate assembly, a stator assembly and a rotor assembly capable of rotating relative to the stator assembly; the cover plate assembly comprises at least one electric brush, an electric brush terminal and a cover plate bearing; the material of the electric brush is Agpd 50; the material of the brush terminal is selected from copper and tin; the cover plate bearing is made of stainless steel;
the filtering device is electrically connected with an electric brush terminal in the cover plate assembly, the filtering device comprises a PCB circuit board and a filter, and the PCB circuit board is fixed on the cover plate assembly and is electrically connected with the electric brush terminal.
2. The micro DC motor of claim 1, wherein the Agpd50 has a pd content of 50% and a tensile strength of 347N/mm2And the hardness of the finished composite layer is HV 200.
3. The micro dc motor of claim 1, wherein the filter is a BDL filter.
4. The micro dc motor of claim 1, wherein the PBC board has 2 input points, 2 output points, and 4 ground points.
5. The micro dc motor according to any one of claims 1 to 4, wherein the stator assembly comprises a housing, a bearing, a magnetic strip; a main shaft through hole is formed in the center of the bottom of the machine shell, the bearing is pressed into the main shaft through hole in the bottom of the machine shell, and the magnetic strip is pressed into the inner wall of the machine shell;
wherein, the casing chooses stainless steel material for use.
6. The micro dc motor according to claim 5, further comprising a conductive device;
the conducting device comprises a conducting strip, one end of the conducting strip is welded with the grounding point of the PCB, and the other end of the conducting strip is welded on the periphery of the shell.
7. The micro direct current motor according to any one of claims 1 to 4, wherein the rotor assembly comprises an insulation sheet, a silicon steel sheet, an output shaft, a sleeve, a coil winding, a commutator, a varistor and an oil baffle; the output shaft is assembled in the central hole of the silicon steel sheet, and the sleeve is sleeved in the output shaft;
the silicon steel sheet is provided with the insulating sheet; the commutator is sleeved at the shell end of the output shaft; the coil winding is wound on the silicon steel sheet through the commutator leg; the piezoresistor is welded with the leg of the commutator and is pressed on the coil winding; the oil baffle plate is sleeved on the output shaft and pressed on the commutator.
8. The micro direct current motor according to claim 7, wherein the commutator is formed by gold plating and polishing and oiling; the commutator is provided with an Ag alloy surface, the Ag alloy surface is coated with an Au layer, the thickness of the Au layer is less than 0.2 mu m, and the Ag alloy is protected from being corroded by sulfur-containing air.
9. The micro dc motor according to any one of claims 1 to 4, wherein the cap assembly further comprises a cap plate, a middle plate, a brush A, a brush B;
the cover plate is provided with a central hole, and the cover plate bearing is pressed in the central hole of the cover plate; the middle plate is pressed on the cover plate, and a foot rest of the electric brush is embedded in the positioning groove of the middle plate and transversely arranged on the inner side of the middle plate.
10. The miniature dc electric machine according to any of claims 1-4, 7 or 8, wherein a surface of said segment is ribbed along a direction extending a length of said segment to increase a contact point between said brush and a commutator of said rotor assembly.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111222567.XA CN113872373A (en) | 2021-10-20 | 2021-10-20 | Miniature DC motor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111222567.XA CN113872373A (en) | 2021-10-20 | 2021-10-20 | Miniature DC motor |
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| CN113872373A true CN113872373A (en) | 2021-12-31 |
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