Electric brush carrier and motor with same

Abstract

The invention relates to the technical field of electric brush carriers, in particular to an electric brush carrier and a motor with the electric brush carrier, and the electric brush carrier comprises a carrier body, the carrier body is provided with a carbon brush seat, and the middle part of the carbon brush seat is communicated to form a channel for a carbon brush to slide; the pressing assembly is provided with at least one group of pressing assemblies which are installed on the carbon brush seat and apply pressure to the carbon brush to move towards the commutator, the pressing assembly comprises an adjusting column installed on the carbon brush seat, a pressing coil spring is installed on the adjusting column, and the pressing coil spring is attached to the carbon brush; the pressure compensation mechanism is installed on the frame body and used for compensating the reduced elastic force of the pressing coil spring. The pressure compensation mechanism has the effects that the pressure fluctuation of the carbon brush is reduced, and the abrasion and eccentric wear rate is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of brush holders, and more particularly to a brush holder and a motor having the same. Background Technology

[0002] In the field of electric motors, especially DC and brushed motors, the brush holder is a key component that directly affects the motor's commutation performance, operational stability, and service life. With the increasing demands on motor performance from industrial equipment, new energy vehicles, and home appliances, traditional brush holders have revealed problems such as large pressure fluctuations, uneven wear, and severe vibration misalignment under high-speed, high-load conditions. This results in short brush life, large commutation sparks, and excessive temperature rise, severely restricting the reliability and energy efficiency of the motor.

[0003] Currently, common brush holders typically include a split frame, which is assembled from multiple parts. Due to assembly tolerances, the overall rigidity may be insufficient. In addition, after long-term use, spring fatigue or carbon brush wear will lead to pressure decay. That is, as the carbon brush wears, the pressure will continue to decrease over time, which may lead to increased contact resistance and intensified commutation sparking. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a brush holder that reduces carbon brush pressure fluctuation and wear rate, and a motor having the same.

[0005] The above-mentioned objective of this invention is achieved through the following technical solutions: A brush holder includes: a frame, on which: A carbon brush holder, wherein a channel for the carbon brush to slide is formed through the middle of the carbon brush holder; The clamping assembly includes at least one set of pressure mounted on the carbon brush holder, which applies pressure to the carbon brush to move toward the commutator. The clamping assembly includes an adjusting post mounted on the carbon brush holder, and a clamping coil spring mounted on the adjusting post, the clamping coil spring being in contact with the carbon brush. A pressure compensation mechanism is installed on the frame to compensate for the reduced elasticity of the compression spring.

[0006] As a specific embodiment of the brush holder disclosed in this invention, the carbon brush holder has a clearance groove, the adjusting column is rotatably mounted in the clearance groove, the adjusting column has a through-hole with a serrated groove, the adjusting column forms several limiting teeth at the position of the fitting groove, a one-way rotation mechanism is provided in the fitting groove, the one-way rotation mechanism includes a rotating plate, the rotating plate is engaged with the inner teeth formed by the fitting groove, a one-way spring is fixedly connected to the rotating plate, and a limiting block is attached to the rotating plate.

[0007] As a specific embodiment of the brush holder disclosed in this invention, the compression spring has several protrusions on the side facing the carbon brush.

[0008] As a specific embodiment of a brush holder disclosed in this invention, the pressure compensation mechanism includes: A limiting plate is installed on the carbon brush holder; A compensating spring, one end of which is fixed to the limiting plate, and the other end of which is connected to the compression coil spring.

[0009] As a specific embodiment of the brush holder disclosed in this invention, a compression plate is provided at one end of the compensating spring facing the compression coil spring.

[0010] As a specific embodiment of the brush holder disclosed in this invention, it also includes several positioning posts, which are in the form of snap-fit.

[0011] As a specific embodiment of the brush holder disclosed in this invention, it also includes several positioning slots, each of which is formed by two opposing positioning pieces.

[0012] As a specific embodiment of the brush holder disclosed in this invention, it also includes a connecting buckle, which is installed on the side of the holder.

[0013] As a specific embodiment of the brush holder disclosed in this invention, it also includes a rotor hole, which is located in the middle of the holder. A guide post is provided on the side of the rotor hole, and the side wall of the guide post fits against the periphery of the rotor hole.

[0014] The present invention also discloses an electric motor, including a brush assembly, wherein the brush assembly employs the aforementioned brush holder.

[0015] In summary, the present invention has at least one of the following beneficial technical effects: 1. The sawtooth-shaped fitting groove of the adjusting column of the brush holder disclosed in this invention and the one-way rotation mechanism constitute the core adjusting unit, which can adjust the preload of the compression spring. When rotating, the preload of the compression spring can be adjusted. When rotating in the opposite direction, the limit block is rigidly locked, which reduces the problem of easy loosening of traditional thread adjustment.

[0016] 2. The protrusion of the clamping spring of the brush holder disclosed in this invention abuts against the back of the carbon brush in point contact, thereby increasing the contact area with the carbon brush, improving the coefficient of friction, and greatly improving the pressure transmission efficiency; 3. The pressure compensation mechanism fixes the compensation spring through the limiting plate. The arc-shaped extrusion plate at its end is fully in contact with the clamping coil spring. When the carbon brush wears and shortens, the clamping coil spring releases its elastic force to push the extrusion plate to move. The compensation spring is compressed to generate a reverse thrust, thereby achieving dynamic pressure balance. 4. The brush holder disclosed in this invention is formed by precision injection molding of an integral engineering plastic frame and symmetrically distributed carbon brush holders, eliminating the cumulative tolerance of separate assembly. Combined with the stress relief groove at the base of the positioning column and the bidirectional elastic buckle design at the top, the vibration resistance is greatly improved, ensuring that the brush holder maintains geometric accuracy in high-speed motors for a long time. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of one embodiment of a brush holder disclosed in this invention; Figure 2 This is a schematic diagram of the structure of a brush holder according to one embodiment of the present invention; Figure 3 This is a schematic diagram of the clamping assembly of one embodiment of a brush holder disclosed in this invention; Figure 4 This is a schematic diagram showing the cooperation between the adjusting column and the one-way rotation mechanism in one embodiment of a brush holder disclosed in this invention.

[0018] Figure label: 1. Frame; 11. Positioning column; 111. Stress relief groove; 12. Positioning groove; 121. Positioning plate; 13. Rotor hole; 14. Guide column; 2. Carbon brush holder; 21. Carbon brush channel; 22. Clearance groove; 3. Clamping assembly; 31. Adjusting column; 311. Fitting groove; 32. Clamping coil spring; 321. Protrusion; 33. Pressure compensation mechanism; 331. Limiting plate; 332. Compensating spring; 333. Extrusion plate; 4. One-way rotation mechanism; 41. Rotating plate; 42. One-way spring; 43. Limit block. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the accompanying drawings.

[0020] Please see Figure 1-4 The present invention discloses a brush holder, which includes an integrally molded engineering plastic frame 1. The upper surface of the frame 1 is provided with two symmetrically distributed carbon brush holders 2. Each carbon brush holder 2 is integrally formed with the frame 1 by precision injection molding, thereby reducing the cumulative tolerance caused by separate assembly.

[0021] A rectangular cross-section carbon brush channel 21 is machined through the center of the carbon brush holder 2 along the axial direction. A dynamic fit clearance is reserved on one side of the width direction of the carbon brush channel 21, which allows for thermal expansion of the carbon brush while suppressing radial wobble. A clearance groove 22 is provided on the carbon brush holder 2. Each set of carbon brush holders 2 is equipped with at least one set of clamping components 3. The clamping components 3 apply pressure to the carbon brush as it moves towards the commutator. The clamping components 3 include an adjusting column 31, a clamping coil spring 32, and a pressure compensation mechanism 33.

[0022] The adjusting column 31 is machined from hardened stainless steel and is installed in the clearance groove 22 on the side wall of the carbon brush holder 2. The clearance groove 22 has a U-shaped opening structure. A serrated fitting groove 311 is machined radially through the center of the adjusting column 31. A one-way rotation mechanism 4 is provided in the fitting groove 311. The one-way rotation structure allows the adjusting column 31 to rotate only in one direction. The one-way rotation mechanism 4 includes a rotating plate 41, which engages with the internal teeth formed by the fitting groove 311. A one-way spring 42 is fixedly connected to the rotating plate 41, and a limiting block 43 is attached to the rotating plate 41. When the adjusting column 31 is rotated, the rotating plate 41 allows the adjusting column 31 to rotate in one direction. After rotation, the one-way spring 42 returns the rotating plate 41 to its original position. When rotating in the opposite direction, the adjusting column 31 cannot rotate in the opposite direction due to the presence of the limiting block 43. It should be understood that a fitting block that mates with the fitting groove 311 can be configured to facilitate the rotation of the adjusting block.

[0023] The compression spring 32 is made of alloy strip wound together and is fitted onto the outer diameter of the adjusting column 31 after installation. Several protrusions 321 are provided on the side of the spring facing the adjusting column 31. Each protrusion 321 is hemispherical and abuts against the back of the carbon brush in point contact. By using the protrusions 321 of the compression spring 32 to abut against the back of the carbon brush in point contact, the overall contact area between the compression spring 32 and the carbon brush is increased, thereby improving the overall coefficient of friction and significantly enhancing the pressure transmission efficiency.

[0024] The pressure compensation mechanism 33 includes a limiting plate 331 and a compensation spring 332. The limiting plate 331 is fixed to the side wall of the carbon brush holder 2. One end of the compensation spring 332 is fixedly connected to the limiting plate 331, and the other end is connected to a pressing plate 333. The contact surface of the pressing plate 333 facing the pressing spring 32 is designed to be arc-shaped and fits against the pressing spring 32.

[0025] When the carbon brush shortens due to wear, the clamping spring 32 rebounds, pushing the pressing plate 333 to move. At this time, the clamping spring 32 reduces its elastic force due to the release of its elastic force. The thrust of the compensating spring 332 then compensates for the reduced elastic force of the clamping spring 32. By adjusting the initial elastic force of the clamping spring 32 and the initial elastic force of the compensating spring 332, the fluctuation of carbon brush pressure caused by wear throughout the entire process can be reduced to ±10%, which is far superior to the ±30% fluctuation of the traditional structure.

[0026] As a specific embodiment of the present invention, a magnetic encoder can be integrated into the end of the adjusting column 31, and an external sensor can detect its rotation angle. An angle-pressure database can be established through a pre-calibration experiment. For example, a 10° rotation corresponds to a pressure increase of 0.5N, thereby realizing real-time pressure monitoring and fault early warning.

[0027] The frame 1 is also provided with several positioning posts 11. The base of the positioning post 11 is designed with a stress relief groove 111 and the top is a two-way elastic buckle. The matching motor end cover is provided with a matching structure. The frame 1 is also provided with several positioning slots 12. The positioning slot 12 is formed by two opposing positioning pieces 121. The matching motor end cover is provided with a matching structure.

[0028] The frame 1 has a rotor hole 13 at its center, and at least one guide post 14 is arranged around the rotor hole 13. The guide post 14 is made of copper alloy inlay, and its inner arc surface curvature matches the rotor shaft. In some feasible ways, a spiral cooling channel can be embedded inside the guide post 14, and the external air cooling airflow can reduce the temperature of the brush area.

[0029] In some feasible configurations, a chip removal groove at a 30° angle can be formed at the bottom of the carbon brush channel 21, with the groove extending through the frame 1. Simultaneously, honeycomb-shaped ventilation holes are formed on the side wall of the carbon brush holder 2. During motor operation, centrifugal airflow throws the wear debris out through the chip removal groove, while the ventilation holes create convective heat dissipation, reducing carbon powder deposition by more than 80%.

[0030] Bench tests were conducted on the brush holder of the present invention:

[0031] The present invention also discloses an electric motor, including a brush assembly, the brush assembly including the aforementioned brush holder.

[0032] In some feasible embodiments, the number of commutator segments in the motor disclosed in this invention can be set to 1.8 times the width of the carbon brush; for example, 11 commutator segments are used when the carbon brush width is 6 mm. The commutator surface is micro-textured using a laser to form multiple sets of micropits, thereby storing grease and reducing frictional torque.

[0033] It should be understood that the brush holder assembly can undergo dynamic balancing testing before assembly, specifically by drilling de-balanced holes at asymmetrical positions on the holder 1. After balancing, the residual imbalance should be ≤0.5g·mm, ensuring that the motor vibration speed is ≤1.0mm / s at 20000rpm.

[0034] Specifically, but not limited to, a composite buffer layer can be added between the frame 1 and the motor mounting surface. This buffer layer consists of a stainless steel substrate and a rubber-fiber composite pad bonded to it. When the buffer layer is compressed, it generates nonlinear damping, suppressing the 20–500Hz vibration transmission rate to below 15%, thereby further improving the stability of the motor during operation.

[0035] Cooling air ducts can also be opened on the motor end cover. The airflow is divided into two paths, one of which cools the windings and the other blows directly to the carbon brush area through the inner channel of the guide column 14.

[0036] The working process of this invention is as follows: First, the carbon brush pressure is loaded and initially adjusted. The compression spring 32 is sleeved on the quenched stainless steel adjusting column 31. The protrusion 321 at the end of the spring presses against the back of the carbon brush in a point contact manner to apply initial pressure. When the adjusting column 31 is rotated, its central sawtooth-shaped fitting groove 311 cooperates with the one-way rotation mechanism 4. When rotating in the forward direction, the adjusting column 31 drives the spring to tighten and increase pressure. When the rotation stops, the limit block 43 locks the rotating plate 41 to achieve self-locking and prevent loosening.

[0037] During operation, the carbon brushes and rotor experience wear and tear. When the carbon brushes wear down and shorten, the compression spring 32 rebounds and releases its elastic force, pushing the extrusion plate 333 towards the compensating spring 332. The compensating spring 332 is compressed, generating a reverse thrust that dynamically offsets the decrease in the spring force. By matching the stiffness of the spring and the compensating spring 332, pressure fluctuations are kept ≤±10%.

[0038] When assembling and using this brush holder, the positioning posts 11 and positioning slots 12 on the holder 1 achieve rapid positioning. At the same time, when the motor is running, the centrifugal airflow can throw the carbon powder out along the chip removal groove, the honeycomb ventilation holes on the side wall form convection, and the spiral cooling channel inside the guide post 14 guides the airflow to blow directly onto the carbon brush area.

[0039] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A brush holder, characterized in that It comprises: a frame (1) on which is mounted: a carbon brush seat (2) with a passage formed in the middle for the sliding of a carbon brush; a compression assembly (3) provided with at least one set of compression springs (32) mounted on the carbon brush seat (2) to provide pressure for the displacement of the carbon brush towards the commutator, the compression assembly (3) comprising an adjusting column (31) mounted on the carbon brush seat (2), the adjusting column (31) being provided with the compression springs (32) mounted thereon and in contact with the carbon brush; a pressure compensation mechanism (33) mounted on the frame (1) to compensate for the reduced elasticity of the compression springs (32).

2. A brush holder according to claim 1, characterised in that: The carbon brush seat (2) is provided with a clearance groove (22), the adjusting column (31) is rotatably mounted at the position of the clearance groove (22), the adjusting column (31) is provided with a fitting groove (311) formed in the middle, the fitting groove (311) is zigzag-shaped, the adjusting column (31) is provided with a plurality of limiting teeth at the position of the fitting groove (311), the fitting groove (311) is provided with a one-way rotation mechanism (4), the one-way rotation mechanism (4) comprises a rotating plate (41) in contact with the internal teeth formed by the fitting groove (311), the rotating plate (41) is fixedly connected with a one-way spring (42), and the rotating plate (41) is provided with a limiting block (43).

3. A brush holder according to claim 2, characterised in that: The side of the compression spring towards the carbon brush is provided with a plurality of protrusions (321).

4. A brush holder according to claim 1, characterized in that: The pressure compensation mechanism (33) comprises: a limiting plate (331) mounted on the carbon brush seat (2); a compensation spring (332) having one end fixedly connected to the limiting plate (331) and the other end connected to the compression spring (32).

5. A brush holder according to claim 4, characterised in that: The end of the compensation spring (332) towards the compression spring (32) is provided with a pressing plate (333).

6. A brush holder according to any one of claims 1-5, characterized in that: It further comprises a plurality of positioning columns (11) in the form of buckles.

7. A brush holder according to any one of claims 1-5, characterized in that: It further comprises a plurality of positioning grooves (12), each of which is formed by two opposite positioning pieces (121).

8. A brush holder according to any one of claims 1-5, characterized in that: It further comprises a connecting buckle mounted on the side edge of the frame (1).

9. A brush holder according to any one of claims 1-5, characterized in that: It further comprises a rotor hole (13) located at the middle position of the frame (1), the rotor hole (13) is provided with a guide column (14) on the side edge, and the side wall of the guide column (14) is in contact with the circumferential side of the rotor hole (13).

10. An electric machine characterized by: It comprises a brush assembly, the brush assembly adopts the brush holder according to any one of claims 1 to 9. It comprises a brush assembly, the brush assembly adopts the brush holder according to any one of claims 1 to 9.

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