Direct current motor with anti-electromagnetic interference structure

Abstract

The invention relates to a direct current motor with an anti-electromagnetic interference structure in the field of motors, which is characterized in that the surfaces of a commutator and an electric brush are blown in real time through a magnetic shielding cylinder arranged on the outer side of the commutator and an air blowing blade arranged in the magnetic shielding cylinder, and carbon powder on the surfaces of the commutator and the electric brush is cleaned; the commutator and the electric brush are subjected to synchronous blowing heat dissipation, so that the commutator and the electric brush have relatively good contact stability, the condition of contact resistance increase caused by carbon powder accumulation is reduced, the probability of arc generation between the commutator and the electric brush is reduced, and the electromagnetic compatibility of the motor is further improved; the influence of a high-frequency magnetic field generated by the arc on a rotor winding coil is reduced, and electromagnetic interference is further reduced; in addition, the insulating groove formed in the commutator improves the collecting and cleaning effects of the carbon powder, and the insulating groove is matched with the diversion disc to realize ejection of the lower contact surface of the electric brush, so that the cleaning effect of the carbon powder is further improved.

Description

Technical Field

[0001] The present invention relates to an anti-electromagnetic interference motor, and particularly to a DC motor with an anti-electromagnetic interference structure applied to the field of motors. Background Art

[0002] The core source of electromagnetic interference inside a DC motor lies in the arc sparks generated when the carbon brush interacts with the commutator. Specifically, when the carbon brush slides on the surface of the commutator for commutation, arc discharges will be triggered due to poor contact or current mutation. These arcs not only cause energy loss, but more importantly, they will excite high-frequency magnetic fields and become the main source of electromagnetic interference. In addition, during the frequent frictional contact between the commutator and the carbon brush, they will gradually wear and generate carbon powder. If these carbon powders are not cleaned in time, they are likely to accumulate on the surface of the commutator, forming a covering layer with poor electrical conductivity. The accumulation of carbon powder not only exacerbates the poor contact between the carbon brush and the commutator, but also further promotes the generation of arcs, forming a vicious cycle: the increase in carbon powder makes arcs more likely to occur, and the arcs promote the generation of more carbon powder, thus exacerbating the electromagnetic interference problem.

[0003] The patent with the publication number CN101345449A discloses an anti-electromagnetic interference motor. Its characteristics are that one or more shielding sleeves (3) are wrapped outside the fixed magnetic tile sleeve (4) inside the motor housing (2); the DC motor or AC motor is installed inside the said motor housing (2); the shielding sleeve (3) and the fixed magnetic tile sleeve (4) are movably matched. Due to the multi-layer shielding inside the motor housing, the anti-electromagnetic interference ability of the motor is greatly improved. Especially for the cash register, due to the multi-layer shielding of the motor, the electromagnetic interference can be effectively resisted, thus ensuring the counting accuracy of the cash register.

[0004] The above patent improves the anti-electromagnetic interference ability of the motor by wrapping the motor with a shielding sleeve and a magnetic tile sleeve. However, the interaction between the commutator and the carbon brush of the motor itself will generate arcs to form high-frequency magnetic fields, and the high-speed and high-temperature friction between the commutator and the carbon brush will increase the accumulation of carbon powder, further increasing the electromagnetic interference inside the motor. Summary of the Invention

[0005] Aiming at the above-mentioned prior art, the technical problem to be solved by the present invention is that the commutator and carbon brush of the existing DC motor will increase the accumulation of carbon powder under high-temperature and high-speed conditions, increasing the electromagnetic interference inside the motor.

[0006] To solve the above problems, the present invention provides a DC motor with an anti-electromagnetic interference structure, including a housing; a rear end cover is fixedly connected to the rear end of the housing, and a rotor shaft is rotatably connected to the central positions of both the housing and the rear end cover. A core winding is fixedly connected to the part of the rotor shaft located inside the housing, and a stator is fixedly connected to the inner wall of the housing and disposed outside the core winding; a commutator is fixedly connected to one side of the rotor shaft facing the rear end cover, a magnetic shielding cylinder fixedly connected to the rear end cover is sleeved outside the commutator, and a pair of carbon brushes in contact with the commutator are fixedly connected to the magnetic shielding cylinder; a blower blade fixedly connected to the rotor shaft is provided inside the magnetic shielding cylinder, an air inlet hole communicating with the inner cavity of the magnetic shielding cylinder is opened on the rear end cover, and an exhaust pipe extending outside the rear end cover is communicated with one end of the magnetic shielding cylinder away from the blower blade.

[0007] In the above DC motor with an anti-electromagnetic interference structure, by providing a blower blade disposed opposite to the commutator, the generation and accumulation of carbon powder are reduced and the working temperature is lowered, thereby reducing the probability of arc generation.

[0008] As a further improvement of the present invention, the commutator includes an insulating seat, mounting grooves are opened on the outer surface of the insulating seat and are circumferentially and equidistantly distributed, commutator segments are fixedly nested in the mounting grooves, insulating grooves are provided between adjacent mounting grooves, and both ends of the insulating grooves extend to the end faces of the two side walls of the insulating seat.

[0009] As a further improvement of the present invention, a flow guiding disk is fixedly connected inside the magnetic shielding cylinder, the flow guiding disk is disposed between the commutator and the blower blade, first blowing holes facing the commutator segments and second blowing holes matching with the insulating grooves are opened on the flow guiding disk, and the numbers of both the first blowing holes and the second blowing holes are multiple and are circumferentially and equidistantly distributed on the flow guiding disk.

[0010] As a further improvement of the present invention, an inclined bottom surface inclined relative to the flow guiding disk is provided in the insulating groove, a horizontal bottom surface abuts against one side of the inclined bottom surface away from the flow guiding disk, the horizontal bottom surface is parallel to the lower end surface of the carbon brush, and the cooperation of the inclined bottom surface and the horizontal bottom surface enables the air flow entering the insulating groove to blow towards the lower end surface of the carbon brush.

[0011] As a further improvement of the present invention, the magnetic shielding cylinder and the flow guiding disk are made of magnetic shielding materials, the magnetic shielding material is one of permalloy and ferrite, the magnetic shielding cylinder is a cylindrical structure with one end open, the open end of the magnetic shielding cylinder is fixedly connected to the inner wall of the rear end cover by means of bolts, the commutator extends outside the magnetic shielding cylinder and is rotatably connected to the magnetic shielding cylinder, the flow guiding disk is in an annular disk shape, and the rotor shaft penetrates through the flow guiding disk and is rotatably connected to it.

[0012] As a further improvement of the present invention, a first dust-proof net is fixedly connected in the air inlet hole, a dust collecting cylinder is installed on the exhaust pipe, and a second dust-proof net is fixedly connected to the connection part of the dust collecting cylinder and the exhaust pipe on the side facing the rear end cover.

[0013] As a further improvement of the present invention, the brush includes an insulating shell that penetrates through the magnetic shielding cylinder and is fixedly connected thereto. A carbon block that abuts against the commutator is slidably connected inside the insulating shell, and a spring that abuts against the outer end of the carbon block is provided inside the insulating shell.

[0014] As a further improvement of the present invention, the insulating seat has a frustum-shaped structure, and the installation groove and the insulating groove are formed on the circumferential side wall of the insulating seat.

[0015] In summary, through the magnetic shielding cylinder provided outside the commutator and the blower blades provided inside the magnetic shielding cylinder in the present invention, during the operation of the motor, the surfaces of the commutator and the brush are blown in real time, the carbon powder on the surfaces of the commutator and the brush is cleaned, and the commutator and the brush are blown and cooled synchronously, so that the commutator and the brush have better contact stability, reducing the increase in contact resistance caused by the accumulation of carbon powder, reducing the probability of arc generation between the commutator and the brush, and thus improving the electromagnetic compatibility of the motor; at the same time, the blowing and cooling not only improves the contact effect between the commutator and the brush, but also reduces the speed of carbon powder generation and prolongs the service life of the commutator and the brush; in addition, the magnetic shielding cylinder has a good magnetic field shielding effect, reducing the influence of the high-frequency magnetic field generated by the arc on the rotor winding coil and further reducing electromagnetic interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a three-dimensional structural schematic diagram of the present application;

[0017] Figure 2 is an internal structural schematic diagram of the housing in the present application;

[0018] Figure 3 is a transverse sectional structural schematic diagram of the present application;

[0019] Figure 4 is Figure 3 an enlarged structural schematic diagram of part A in

[0020] Figure 5 a schematic diagram of the air flow inside the motor;

[0021] Figure 6 is an exploded installation schematic diagram of the brush and the magnetic shielding cylinder in the present application;

[0022] Figure 7 is an assembly schematic diagram of the insulating seat and the commutator segment in the present application;

[0023] Figure 8 is a sectional structural schematic diagram of the insulating seat at the position of the insulating groove in the present application;

[0024] Figure 9 is a sectional structural schematic diagram of the flow guide plate in the present application;

[0025] Figure 10 Schematic diagram of air flow blowing through the insulating groove on the lower contact surface of the carbon brush.

[0026] Description of the reference numerals in the figure:

[0027] 1. Housing; 2. Rear end cover; 201. Air inlet hole; 3. Rotor shaft; 4. Iron core winding; 5. Stator; 6. Commutator; 601. Insulating seat; 602. Installation groove; 603. Insulating groove; 6031. Inclined bottom surface; 6032. Horizontal bottom surface; 604. Commutator segment; 6031. Inclined bottom surface; 6032. Horizontal bottom surface; 7. Magnetic shielding cylinder; 8. Carbon brush; 801. Insulating shell; 802. Carbon block; 803. Spring; 9. First dust-proof net; 10. Exhaust pipe; 11. Dust collecting cylinder; 12. Second dust-proof net; 13. Deflector; 1301. First blowing hole; 1302. Second blowing hole; 14. Blowing blade. Specific embodiments

[0028] The following will describe in detail two embodiments of the present application with reference to the accompanying drawings.

[0029] The first embodiment:

[0030] Figures 1-6 There is shown a DC motor with an anti-electromagnetic interference structure, including a housing 1; a rear end cover 2 is fixedly connected to the rear end of the housing 1, a rotor shaft 3 is rotatably connected at the central positions of the housing 1 and the rear end cover 2, a part of the rotor shaft 3 located inside the housing 1 is fixedly connected with an iron core winding 4, and a stator 5 arranged outside the iron core winding 4 is fixedly connected to the inner wall of the housing 1; a commutator 6 is fixedly connected to one side of the rotor shaft 3 facing the rear end cover 2, a magnetic shielding cylinder 7 fixedly connected to the rear end cover 2 is sleeved outside the commutator 6, and a pair of carbon brushes 8 abutting against the commutator 6 are fixedly connected to the magnetic shielding cylinder 7; a blowing blade 14 fixedly connected to the rotor shaft 3 is arranged inside the magnetic shielding cylinder 7, an air inlet hole 201 communicating with the inner cavity of the magnetic shielding cylinder 7 is opened on the rear end cover 2, and one end of the magnetic shielding cylinder 7 away from the blowing blade 14 communicates with an exhaust pipe 10 extending outside the rear end cover 2.

[0031] Specifically, please refer to Figure 5, when the motor is working, when an arc is generated between the carbon brush 8 and the commutator 6, the magnetic shielding cylinder 7 shields the high-frequency magnetic field generated by the arc, avoiding the magnetic field generated by the arc from affecting the coils on the iron core winding 4 and reducing the electromagnetic interference inside the motor; at the same time, the rotor shaft 3 drives the blower blade 14 to rotate, and the blower blade 14 blows the external air flow entering from the air inlet hole 201 towards the commutator 6 and the carbon brush 8, and the air flow flowing through the commutator 6 and the carbon brush 8 is discharged to the outside of the housing 1 through the exhaust pipe 10. During this process, the carbon powder on the surfaces of the commutator 6 and the carbon brush 8 is blown and cleaned. By cleaning the carbon powder on the surfaces of the commutator 6 and the carbon brush 8, the probability of carbon powder accumulation is reduced, and thus the probability of arc generation is reduced, improving the electromagnetic compatibility. At the same time, the commutator 6 and the carbon brush 8 are blown and cooled, reducing the working temperature of the carbon brush 8 and the commutator 6, slowing down the wear of the carbon brush 8, and further reducing the rate of carbon powder generation, further extending the service life of the carbon brush 8 and the contact effect between the carbon brush 8 and the commutator 6.

[0032] Compared with traditional DC motors, in the present invention, by providing the magnetic shielding cylinder 7 outside the commutator 6 and the blower blade 14 inside the magnetic shielding cylinder 7, when the motor is working, the surfaces of the commutator 6 and the carbon brush 8 are blown in real time, the carbon powder on the surfaces of the commutator 6 and the carbon brush 8 is cleaned, and the commutator 6 and the carbon brush 8 are blown and cooled synchronously, so that the commutator 6 and the carbon brush 8 have better contact stability, reducing the increase in contact resistance caused by carbon powder accumulation, reducing the probability of arc generation between the commutator 6 and the carbon brush 8, and thus improving the electromagnetic compatibility of the motor; at the same time, the blowing and cooling not only improves the contact effect between the commutator 6 and the carbon brush 8, but also reduces the speed of carbon powder generation and extends the service life of the commutator 6 and the carbon brush 8; in addition, the magnetic shielding cylinder 7 has a good magnetic field shielding effect, reducing the influence of the high-frequency magnetic field generated by the arc on the rotor winding coil and further reducing the electromagnetic interference.

[0033] Please refer to Figure 5 and Figure 6 , the magnetic shielding cylinder 7 is a cylindrical structure with one end open, and the open end of the magnetic shielding cylinder 7 is fixedly connected to the inner wall of the rear end cover 2 by means of bolts, and the commutator 6 extends to the outside of the magnetic shielding cylinder 7 and is rotatably connected to the magnetic shielding cylinder 7.

[0034] Specifically, the cylindrical magnetic shielding cylinder 7 facilitates blowing the air flow generated by the blower blade 14 towards the commutator 6 and the carbon brush 8, improving the blowing effect, and thus improving the cleaning and cooling effects.

[0035] In this embodiment, the magnetic shielding cylinder 7 is made of a magnetic shielding material, and the magnetic shielding material is one of permalloy and ferrite.

[0036] Specifically, the magnetic shielding cylinder 7 has a good electromagnetic shielding effect on the high-frequency magnetic field generated by the arc.

[0037] Please refer toFigure 5 , a first dust-proof net 9 is fixedly connected inside the air inlet hole 201, a dust collection cylinder 11 is installed on the exhaust pipe 10, and a second dust-proof net 12 is fixedly connected to the communication part of the dust collection cylinder 11 and the exhaust pipe 10 on the side facing the rear end cover 2.

[0038] Specifically, the carbon powder cleaned by blowing is centrally collected through the dust collection cylinder 11, which is convenient for subsequent recycling and utilization; at the same time, the first dust-proof net 9 reduces the pollution of the commutator 6 and the carbon brush 8 by the dust in the external air flow, and the second dust-proof net 12 intercepts the collected carbon powder in the dust collection cylinder 11.

[0039] Please refer to Figure 6 , the carbon brush 8 includes an insulating shell 801 that penetrates and is fixedly connected to the magnetic shielding cylinder 7, a carbon block 802 that is slidably connected inside the insulating shell 801 and abuts against the commutator 6, and a spring 803 that is arranged inside the insulating shell 801 and abuts against the outer end of the carbon block 802.

[0040] Specifically, as the carbon block 802 wears, the spring 803 makes the carbon block 802 fit on the surface of the commutator 6, improving the contact effect between the carbon brush 8 and the commutator 6 and reducing the probability of arc generation.

[0041] The second implementation mode:

[0042] Figures 7-10 A DC motor with an anti-electromagnetic interference structure is shown. On the basis of the first implementation mode, the commutator 6 includes an insulating seat 601. The outer surface of the insulating seat 601 is provided with mounting grooves 602 that are evenly distributed in a circular pattern. A commutator segment 604 is fixedly nested inside the mounting grooves 602. An insulating groove 603 is provided between adjacent mounting grooves 602, and both ends of the insulating groove 603 extend to the end faces of the two side walls of the insulating seat 601.

[0043] Specifically, when the carbon brush 8 slides on the surface of the insulating seat 601, it is easier to bring the carbon powder into the insulating groove 603, reducing the carbon powder accumulated on the surface of the commutator segment 604, thereby improving the carbon powder blowing and cleaning effect. At the same time, when the air flow blows the insulating seat 601, the air flow takes away the carbon powder through the insulating groove 603, further improving the cleaning effect.

[0044] Please refer to Figure 7 and Figure 8 , the insulating seat 601 has a frustum-shaped structure, and the mounting grooves 602 and the insulating grooves 603 are provided on the circumferential side wall of the insulating seat 601.

[0045] Please refer to Figure 3 and Figure 9, a flow guiding disk 13 is fixedly connected inside the magnetic shielding cylinder 7. The flow guiding disk 13 is arranged between the commutator 6 and the blower blades 14. The flow guiding disk 13 is provided with a first blowing hole 1301 facing the commutator segment 604 and a second blowing hole 1302 cooperating with the insulating groove 603. The numbers of both the first blowing hole 1301 and the second blowing hole 1302 are multiple and are distributed on the flow guiding disk 13 at equal circumferential intervals.

[0046] Specifically, when the air flow blows towards the flow guiding disk 13, the first blowing hole 1301 makes the air flow blow more concentratedly towards the commutator segment 604, improving the cleaning effect on the commutator segment 604; at the same time, as the commutator 6 rotates with the rotor shaft 3, it intermittently blows into the insulating groove 603, realizing pulse blowing on the insulating groove 603, and further improving the blowing and cleaning effect on the carbon powder in the insulating groove 603.

[0047] Please refer to Figure 3 and Figure 9 , the flow guiding disk 13 is made of a magnetic shielding material. The flow guiding disk 13 has an annular disk structure. The rotor shaft 3 penetrates through the flow guiding disk 13 and is rotatably connected thereto.

[0048] It should be noted that the magnetic shielding material is one of permalloy and ferrite. The flow guiding disk 13 and the magnetic shielding cylinder 7 cooperate to form a closed magnetic shielding barrier, improving the electromagnetic isolation ability.

[0049] Please refer to Figure 8 , an inclined bottom surface 6031 inclined relative to the flow guiding disk 13 is provided in the insulating groove 603. One side of the inclined bottom surface 6031 away from the flow guiding disk 13 abuts against a horizontal bottom surface 6032. The horizontal bottom surface 6032 is arranged parallel to the lower end surface of the carbon brush 8. The cooperation of the inclined bottom surface 6031 and the horizontal bottom surface 6032 makes the air flow entering the insulating groove 603 blow towards the lower end surface of the carbon brush 8.

[0050] Specifically, please refer to Figure 10 , by arranging the cooperation of the inclined bottom surface 6031 and the horizontal bottom surface 6032 in the insulating groove 603, the air flow entering the insulating groove 603 blows towards the lower end surface of the carbon brush 8, performing blowing and cleaning on the lower contact surface of the carbon brush 8, improving the cleanliness of the lower contact surface of the carbon brush 8, thereby improving the contact effect between the carbon brush 8 and the commutator 6, further reducing the probability of arc generation, and improving the electromagnetic compatibility of the motor.

[0051] Combined with the current actual requirements, the above implementation manner adopted in this application, the protection scope is not limited thereto. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of this application still fall within the protection scope of the present invention.

Claims

1. A DC motor with an anti-electromagnetic interference structure, characterized in that: The invention comprises a housing (1); a rear end cover (2) is fixedly connected to the rear end of the housing (1); a rotor shaft (3) is rotatably connected to the center of the housing (1) and the rear end cover (2); a portion of the rotor shaft (3) located inside the housing (1) is fixedly connected to an iron core winding (4); and a stator (5) arranged outside the iron core winding (4) is fixedly connected to the inner wall of the housing (1); a commutator (6) is fixedly connected to the side of the rotor shaft (3) facing the rear end cover (2); and the outer side of the commutator (6) is sleeved with a A magnetic shielding cylinder (7) is fixedly connected to the rear end cover (2), and a pair of brushes (8) abutting against the commutator (6) are fixedly connected to the magnetic shielding cylinder (7); a blast blade (14) fixedly connected to the rotor shaft (3) is arranged inside the magnetic shielding cylinder (7); an air inlet (201) connected to the inner cavity of the magnetic shielding cylinder (7) is opened on the rear end cover (2); and an end of the magnetic shielding cylinder (7) away from the blast blade (14) is connected to an exhaust pipe (10) extending to the outside of the rear end cover (2).

2. A DC motor with an anti-electromagnetic interference structure according to claim 1, characterized in that: The commutator (6) comprises an insulating seat (601), the outer surface of the insulating seat (601) is provided with mounting grooves (602) distributed equidistantly in a circumference, a commutator segment (604) is fixedly nested in the mounting grooves (602), insulating grooves (603) are provided between adjacent mounting grooves (602), and both ends of the insulating grooves (603) extend to the end surfaces of the side walls on both sides of the insulating seat (601).

3. A DC motor with an anti-electromagnetic interference structure according to claim 2, characterized in that: A guide plate (13) is fixedly connected inside the magnetic shielding tube (7), and the guide plate (13) is arranged between the commutator (6) and the blower blade (14). The guide plate (13) is provided with a first blowing hole (1301) facing the commutator segment (604) and a second blowing hole (1302) cooperating with the insulating groove (603). The first blowing hole (1301) and the second blowing hole (1302) are both multiple in number and are equidistantly distributed on the guide plate (13) around the circumference.

4. A DC motor with an anti-electromagnetic interference structure according to claim 3, characterized in that: The insulating groove (603) is provided with an inclined bottom surface (6031) which is inclined opposite to the guide plate (13); the inclined bottom surface (6031) is in contact with a horizontal bottom surface (6032) on the side away from the guide plate (13); the horizontal bottom surface (6032) is arranged parallel to the lower end surface of the brush (8); the inclined bottom surface (6031) and the horizontal bottom surface (6032) cooperate so that the airflow entering the insulating groove (603) is blown toward the lower end surface of the brush (8).

5. A DC motor with an anti-electromagnetic interference structure according to claim 4, characterized in that: The magnetic shielding cylinder (7) and the guide plate (13) are made of magnetic shielding material, and the magnetic shielding material is one of Permalloy and ferrite. The magnetic shielding cylinder (7) is a cylindrical structure with one end open. The open end of the magnetic shielding cylinder (7) is fixedly connected to the inner wall of the rear end cover (2) by bolt fixing. The commutator (6) extends to the outside of the magnetic shielding cylinder (7) and is rotatably connected to the magnetic shielding cylinder 7. The guide plate (13) is an annular disc structure. The rotor shaft (3) passes through the guide plate (13) and is rotatably connected thereto.

6. The DC motor with an anti-electromagnetic interference structure according to claim 1, characterized in that: A first dustproof net (9) is fixedly connected inside the air inlet (201), a dust collecting cylinder (11) is installed on the exhaust pipe (10), and a second dustproof net (12) is fixedly connected at a connection point between the dust collecting cylinder (11) and the exhaust pipe (10) facing the side of the rear end cover (2).

7. The DC motor with an anti-electromagnetic interference structure according to claim 1, characterized in that: The brush (8) comprises an insulating shell (801) that passes through the magnetic shielding cylinder (7) and is fixedly connected thereto, a carbon block (802) that is slidably connected inside the insulating shell (801) and abuts against the commutator (6), and a spring (803) that abuts against the outer end of the carbon block (802) is provided inside the insulating shell (801).

8. The DC motor with an anti-electromagnetic interference structure according to claim 2, characterized in that: The insulating seat (601) is a truncated cone-shaped structure, and the mounting groove (602) and the insulating groove (603) are arranged on the circumferential side wall of the insulating seat (601).

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