A carbon brush assembly

Abstract

This invention provides a carbon brush assembly, including a carbon brush body, a brush holder, and a self-disconnecting unit. The carbon brush body is mounted on one side of the commutator via the brush holder and maintains contact with the commutator. When the carbon brush body wears due to the rotation of the commutator, its length gradually decreases until it reaches a predetermined length. At this time, the brush braid will also separate from the stator due to the self-disconnecting unit, thus breaking the circuit between the stator and the commutator. This avoids the risk of arcing caused by poor contact between the carbon brush body and the commutator, which could damage the surface of the commutator.

Description

Technical Field

[0001] This invention relates to the field of electromechanical systems, and more specifically to a carbon brush assembly. Background Technology

[0002] Currently, the carbon brushes used in brushed motors of power tools come in two types: self-disconnecting and non-self-disconnecting.

[0003] When considering costs, tools typically use non-self-disconnecting carbon brushes. Workers, under continuous operation, are unlikely to frequently check the remaining brush length, making it difficult to determine the accurate time to replace the brushes. If the brushes are not replaced in time, the brush spring force will be insufficient, resulting in poor contact with the commutator. This causes excessive sparking between the brush and the commutator, easily damaging the commutator and affecting the tool's lifespan (see Chinese Utility Model Patent CN207602954U).

[0004] Some high-end brushed motors employ self-breaking carbon brushes. Currently, commercially available self-breaking carbon brushes typically embed an insulator and a compressed spring within the brush body. When the brush wears down to the embedded insulator, the spring pushes out the insulator and simultaneously lifts the brush, breaking the contact between the brush and the commutator. However, this approach has several drawbacks: for example, unstable fuse embedding technology can lead to fuse failure (resulting in large sparks and damage to the commutator), see Chinese Utility Model Patent CN208589622U; furthermore, the fuse design significantly shortens the effective wear length of the carbon brush, correspondingly reducing its lifespan; additionally, the fuse manufacturing process is complex and costly. Summary of the Invention

[0005] To address the above problems, the present invention provides a carbon brush assembly.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A carbon brush assembly, disposed within a motor, includes:

[0008] A carbon brush body is used to electrically connect the commutator and stator of the motor. The carbon brush body is connected to the stator through a brush braid.

[0009] A brush holder, located on one side of the commutator, is used to force the carbon brush body to remain in contact with the commutator;

[0010] A self-disconnecting unit is located on one side of the stator and is used to separate the brush braid from the stator when the carbon brush body wears to a predetermined length.

[0011] Furthermore, the self-disconnecting unit includes a brush braid connector and an adapter, wherein the brush braid connector is detachably connected to the stator via the adapter.

[0012] Furthermore, the brush braid connector electrically connects the brush braid to the stator when the carbon brush body has not worn to a predetermined length, and separates the brush braid from the stator when the carbon brush body wears to the predetermined length.

[0013] Furthermore, the brush braid connector includes a clamping part and a connecting part. The clamping part is detachably connected to the adapter through the connecting part. The clamping part includes two clamping members connected by the connecting part. The two clamping members each have clamping grooves arranged opposite to each other. When the carbon brush body has not worn to a predetermined length, the brush braid is between the clamping grooves. When the carbon brush body wears to the predetermined length, the brush braid disengages from the clamping grooves.

[0014] Furthermore, the clamping part and the connecting part are integrally formed.

[0015] Furthermore, the brush holder has a guide and an elastic element, the carbon brush body is slidably installed in the guide and moves toward the commutator under the push of the elastic element.

[0016] Furthermore, the guide has openings at both ends for the carbon brush body to enter and exit. One end of the carbon brush body extends out of the guide and connects to the commutator, while the other end is connected to the self-disconnecting unit via a brush braid.

[0017] Furthermore, the guide member has a guide groove on the side near the elastic member, and the stroke of the elastic member when pushing the carbon brush body to connect with the commutator matches the extension path of the guide groove.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. In the carbon brush assembly provided by the present invention, the carbon brush body is kept in contact with the commutator under the action of the elastic element. When the carbon brush body is worn due to the rotation of the commutator, its length gradually decreases until it reaches the predetermined length. At this time, the brush braid will also be separated from the stator due to the self-circuit breaking unit, so that the stator and the commutator are disconnected, thus avoiding the risk of the carbon brush body and the commutator causing arcing due to poor contact, resulting in damage to the surface of the commutator.

[0020] 2. The clamping part in this invention is detachably connected to the adapter through the connecting part. The clamping part can adopt a suitable clamping form according to the actual situation, so as to maximize the convenience of the structure.

[0021] 3. The clamping part of the present invention includes two clamping members connected by a connecting part. The two clamping members have clamping grooves arranged opposite to each other. When the carbon brush body is not worn to a predetermined length, the brush braid is clamped between the clamping grooves. When the carbon brush body is worn to a predetermined length, the brush braid is disengaged from the clamping grooves. Thus, the present invention realizes the control of the commutator-stator circuit switching according to the change in the length of the carbon brush body.

[0022] 4. In this invention, the elastic element is a constant force spring. The elastic release of the constant force spring is relatively stable, which prevents the pressure of the carbon brush body on the commutator from fluctuating and causing waste of the carbon brush body. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the assembly of the carbon brush assembly in an embodiment of the present invention;

[0024] Figure 2 for Figure 1 Enlarged view at point A;

[0025] Figure 3 This is a schematic diagram of the carbon brush assembly structure when the carbon brush body has not worn down to a predetermined length in an embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the carbon brush assembly when the carbon brush body is worn to a predetermined length in an embodiment of the present invention;

[0027] Figure 5 This is a schematic diagram of the carbon brush assembly structure in an embodiment of the present invention (the rotor and commutator are not shown).

[0028] Figure 6 This is a front view of the carbon brush assembly in an embodiment of the present invention;

[0029] Figure 7 This is a top view of the carbon brush assembly in an embodiment of the present invention.

[0030] In the diagram: 1. Carbon brush body; 11. Brush braid; 2. Brush holder; 21. Guide component; 211. Guide groove; 22. Elastic component; 221. Free end; 3. Self-disconnecting unit; 31. Brush braid connector; 311. Clamping part; 311a. Clamping component; 311b. Clamping groove; 312. Connecting part; 32. Adapter; 4. Commutator. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] Those skilled in the art will understand that, without conflict, the features in the following embodiments and implementations can be combined with each other.

[0033] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "upper," "lower," "front," and "rear" that indicate orientation or positional relationship are based solely on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0034] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “multiple” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “install,” “connect,” and “link” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be direct or indirect through an intermediate medium, and can be internal communication between two components or an interaction between two components.

[0035] Please see Figure 1-7 The present invention provides a carbon brush assembly installed inside a motor, including a carbon brush body 11, a brush holder 22, and a self-disconnecting unit 33. The carbon brush body 1 is installed on one side of the commutator 4 via the brush holder 2 and maintains contact with the commutator 4. When the carbon brush body 1 wears due to the rotation of the commutator 4, its length gradually decreases until it reaches a predetermined length. At this time, the brush braid 11 will also separate from the stator due to the self-disconnecting unit 3, thus breaking the circuit between the stator and the commutator 4. This avoids the risk of arcing caused by poor contact between the carbon brush body 1 and the commutator 4, which would damage the surface of the commutator 4.

[0036] Please see Figure 2-3 The self-disconnecting unit 3 includes a brush braid connector 31 and an adapter 32. The brush braid connector 31 is detachably connected to the stator through the adapter 32.

[0037] Specifically, one end of the braid connector 31 is detachably mounted on the stator to the adapter 32 via screws.

[0038] Please see Figure 3-4 The brush braid connector 31 electrically connects the brush braid 11 to the stator when the carbon brush body 1 has not worn to a predetermined length, and separates the brush braid 11 from the stator when the carbon brush body 1 has worn to a predetermined length.

[0039] Specifically, when the brush braid 11 is connected to the brush braid connector 31, the commutator 4 is electrically connected to the stator via the carbon brush body 1, the brush braid 11, and the self-disconnecting unit 3. However, when the carbon brush body 1 wears to a predetermined length, the brush braid 11 separates from the stator. This predetermined length is determined based on the distance between the brush holder 2 and the commutator 4 and the stator, as well as the assembly method between the carbon brush body 1 and the brush holder 2, so as to ensure that the brush braid 11 can be stably separated from the stator when the carbon brush body 1 wears to the predetermined length.

[0040] The brush braid connector 31 includes a clamping part 311 and a connecting part 312. The clamping part 311 is detachably connected to the adapter 32 through the connecting part 312. The clamping part 311 includes two clamping members 311a connected through the connecting part 312. The two clamping members 311a have clamping grooves 311b arranged opposite to each other. When the carbon brush body 1 has not worn to a predetermined length, the brush braid 11 is between the clamping grooves 311b. When the carbon brush body 1 wears to the predetermined length, the brush braid 11 disengages from the clamping grooves 311b.

[0041] Specifically, the two clamping grooves 311b are arranged opposite to each other and form a space that is adapted to the brush braid 11, allowing the brush braid 11 to move freely and making the brush braid 11 in stable contact with the clamping part 311.

[0042] The clamping part 311 and the connecting part 312 are integrally formed to form a U-shaped structure, and the connecting part 312 has a certain elasticity, so that the clamping part 311a can stably clamp the brush braid 11.

[0043] Please see Figure 5-7 The brush holder 2 has a guide 21 and an elastic element 22. The carbon brush body 1 is slidably installed in the guide 21 and moves toward the commutator 4 under the push of the elastic element 22.

[0044] Specifically, the free end 221 of the elastic element 22 abuts against the carbon brush body 1, which moves freely inside the guide element 21, causing the carbon brush body 1 to move toward the side that contacts the commutator 4.

[0045] Please see Figure 5 The guide member 21 has openings at both ends for the carbon brush body 1 to enter and exit. One end of the carbon brush body 1 extends out of the guide member 21 and connects to the commutator 4, and the other end is connected to the self-disconnecting unit 3 through the brush braid 11.

[0046] Please see Figure 2 , 5 The guide member 21 has a guide groove 211 on the side near the elastic member 22. The stroke of the elastic member 22 when pushing the carbon brush body 1 to connect with the commutator 4 matches the extension path of the guide groove 211.

[0047] Specifically, when the free end 221 of the elastic element 22 pushes the carbon brush body 1 to connect with the commutator 4, the carbon brush body 1 is worn by the high-speed rotating commutator 4. At this time, the free end 221 of the elastic element 22 moves along the direction of the carbon brush body 1. A guide groove 211 is provided on one side of the guide element 21 to avoid the free end 221 of the elastic element 22 and avoid hindering the movement of the free end 221.

[0048] In summary, the technical problem this invention aims to solve is how to disconnect the circuit when the effective length of the carbon brush 1 is exhausted, while maintaining a stable connection between the carbon brush body 1 and the commutator 4. This invention links the length of the carbon brush body 1 to the on / off state of the commutator 4 circuit, and uses the effective wear length of the carbon brush body 1 as the distance the brush braid 11 can move within the self-disconnecting unit 3. Therefore, when the effective length of the carbon brush is exhausted, the brush braid 11 disengages from the self-disconnecting unit 3, and the circuit between the commutator 4 and the stator is broken. However, at this time, the carbon brush body 1 and the commutator 4 remain in close contact under the action of the brush holder 2. Therefore, an electric arc that would damage the commutator surface, as seen in the method of limiting carbon brushes, will not occur between them, thus protecting the commutator 4 and improving the service life of the motor.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the content described in the above specific embodiments. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A carbon brush assembly disposed within a motor, characterized in that, include: A carbon brush body is used to electrically connect the commutator and stator of the motor. The carbon brush body is connected to the stator through a brush braid. A brush holder, located on one side of the commutator, is used to force the carbon brush body to remain in contact with the commutator; A self-disconnecting unit is located on one side of the stator and is used to separate the brush braid from the stator when the carbon brush body wears to a predetermined length. The self-disconnecting unit includes a brush braid connector and an adapter, wherein the brush braid connector is detachably connected to the stator via the adapter; The brush braid connector electrically connects the brush braid to the stator when the carbon brush body has not worn to a predetermined length, and separates the brush braid from the stator when the carbon brush body wears to the predetermined length. The brush braid connector includes a clamping part and a connecting part. The clamping part is detachably connected to the adapter through the connecting part. The clamping part includes two clamping members connected by the connecting part. The two clamping members each have a clamping groove arranged opposite to each other. When the carbon brush body has not worn to a predetermined length, the brush braid is between the clamping grooves. When the carbon brush body wears to the predetermined length, the brush braid disengages from the clamping grooves.

2. The carbon brush assembly according to claim 1, characterized in that: The clamping part and the connecting part are integrally formed.

3. The carbon brush assembly according to any one of claims 1-2, characterized in that: The brush holder has a guide and an elastic element. The carbon brush body is slidably installed in the guide and moves toward the commutator under the push of the elastic element.

4. The carbon brush assembly according to claim 3, characterized in that: The guide has openings at both ends for the carbon brush body to enter and exit. One end of the carbon brush body extends out of the guide and connects to the commutator, while the other end is connected to the self-disconnecting unit through a brush braid.

5. The carbon brush assembly according to claim 3, characterized in that: The guide member has a guide groove on the side near the elastic member, and the stroke of the elastic member when pushing the carbon brush body to connect with the commutator matches the extension path of the guide groove.

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