Brush holder for direct current motor

Abstract

The invention relates to a brush holder for a direct current motor, and the brush holder comprises a wire which is used for connecting an internal circuit of the motor; the carbon brush body is connected with a motor through the wire, and a U-shaped open slot is formed in one surface, in contact with a commutator, of the carbon brush body, so that the motor outputs stable ripples when the carbon brush body part on one side of the commutator is in contact with an adjacent commutator sheet; and the opening direction of the open slot faces the commutator. The beneficial effects are that one surface of the carbon brush body, which is contacted with the commutator, is provided with the open slot, so that the carbon brush body cannot be contacted with another commutator sheet immediately after leaving one commutator sheet, thereby increasing the error-tolerant rate of a product, and improving the ripple performance of the ripple motor.

Description

Technical Field

[0001] The invention relates to the technical field of carbon brushes, in particular to a brush holder for a DC motor. Background Art

[0002] With the improvement of people's production and living standards, people have put forward higher requirements for the comfort level during vehicle use. In particular, the rapid development of new energy vehicles has brought human-machine interaction and intelligence to a new level. The anti-pinch function of car windows has become a standard configuration of modern cars.

[0003] However, the motors that can currently achieve the anti-pinch function each have their own advantages.

[0004] For example, the Hall anti-pinch motor determines the window position through the Hall signal, and processes the Hall signal through the motor's own chip to achieve one-touch window raising, anti-pinch and other functions; its product technology is mature and the misrecognition rate is low, but the cost is relatively high.

[0005] For example, the ripple anti-pinch motor generates a current ripple signal through the operation of the motor and outputs it to the vehicle controller to achieve functions such as one-touch window raising and anti-pinch. Its product cost is low, but due to the high-precision requirements for manufacturing, it is easily misidentified by the controller and has a high failure rate.

[0006] Considering the product cost, more and more domestic vehicle manufacturers prefer to choose ripple motors to achieve anti-pinch function. However, the traditional ripple motor generates ripples by alternating the number of contacts between the carbon brushes and the commutator segments, so the two carbon brushes inside the motor must be arranged at 180 degrees. Once the angle deviates, it will affect the ripple.

[0007] However, the brush plates of motors are all plastic products, and the product accuracy is difficult to guarantee. In addition, the external temperature and humidity will affect the product size. Therefore, it is necessary to optimize the carbon brush structure and provide a carbon brush that can ensure the stable waveform of the ripple motor output even if the brush plate size accuracy is not high. Summary of the invention

[0008] The present invention aims at the technical problems existing in the prior art and provides a brush holder for a DC motor to solve the technical problem in the prior art that the carbon brushes on both sides of the motor are not at 180° due to excessive product manufacturing precision, resulting in poor motor ripple.

[0009] The technical solution of the present invention to solve the above technical problem is as follows: A brush holder for a DC motor comprises: a wire for connecting an internal circuit of the motor; A carbon brush body is connected to the motor through the wire, and a U-shaped opening groove is provided on the side of the carbon brush body that contacts the commutator, so that when the carbon brush body part on one side of the commutator contacts the adjacent commutator segment, the motor outputs a stable ripple; The opening direction of the open slot faces the commutator.

[0010] As a further technical solution, the open groove is opened along the height direction of the carbon brush body to evenly divide the side of the carbon brush body that contacts the commutator.

[0011] As a further technical solution, the contact surface between the carbon brush body and the commutator is two arc-shaped concave surfaces, and the two arc-shaped concave surfaces are connected by the open groove; The two arc-shaped concave surfaces form a first arc surface in space.

[0012] As a further technical solution, the arc radius of the first arc surface is smaller than the arc radius of the outer surface of the commutator.

[0013] As a further technical solution, the radius R of the circle where the first arc surface is located is 5-5.2 mm.

[0014] As a further technical solution, the arc-shaped concave surface is provided with a plurality of protruding teeth along its width direction, the tooth groove width between adjacent teeth is 0.4-0.6mm, and the depth of the teeth is 0.095-0.2mm.

[0015] As a further technical solution, the carbon brush body further includes a first chamfered surface, and the first chamfered surface is connected to the outer side of the arc-shaped concave surface.

[0016] As a further technical solution, the upper end surface of the carbon brush body is provided with a second chamfered surface and a connecting surface connected in sequence on both sides along the length direction thereof, and the second chamfered surface and the connecting surface are connected on a side close to the commutator through the first chamfered surface; The upper end of the side wall of the carbon brush body is vertically connected to the connecting surface.

[0017] As a further technical solution, the second chamfered surface and the side of the connecting surface close to the commutator are both connected to the upper part of the first island chamfered surface.

[0018] As a further technical solution, the inner concave surface of the opening groove is a second arc surface with a diameter of 0.9-1.1 mm, and the distance between the vertex of the second arc surface and the vertex of the first arc surface is 1.3-1.4 mm.

[0019] The beneficial effects of the present invention are: 1. An open groove is set on the side of the carbon brush body that contacts the commutator, so that the carbon brush body will not immediately contact another commutator segment after leaving one commutator segment, thereby increasing the product's fault tolerance and improving the ripple performance of the ripple motor; 2. The structural design of the first arc surface and its teeth reduces the contact area with the commutator and reduces the initial noise of the motor; 3. Since the carbon brush body will gradually wear out during use, a first chamfered surface is provided to improve structural strength and extend service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 , Figure 2 They are three-dimensional structural schematic diagrams of a brush holder for a DC motor of the present invention from different viewing angles; Figure 3 for Figure 2 A schematic diagram of the enlarged structure of part A; Figure 4 This is a schematic diagram of the top view of the structure after the traditional carbon brush is connected to the commutator.

[0021] In the accompanying drawings, the components represented by the reference numerals are listed as follows: Wire 1; Carbon brush body 2, opening groove 21, inner concave surface 211, arc-shaped concave surface 22, teeth 221, arc connecting surface 23, first chamfered surface 24, upper end surface 25, second chamfered surface 26, connecting surface 27; Commutator 3. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0023] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0024] In the description of the present application, the term "for example" is used to mean "used as an example, illustration or description". Any embodiment described as "for example" in the present application is not necessarily to be construed as being more preferred or advantageous than other embodiments. In order to enable any technician in the field to implement and use the present invention, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present invention can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the present invention obscure. Therefore, the present invention is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in the present application.

[0025] Because the curvature of traditional carbon brushes is different from that of commutators, the single carbon brush and commutator are in line contact at the beginning of operation. In order to ensure that the motor produces a stable ripple waveform that is close to a sine wave, the carbon brushes on both sides of the commutator must be in a straight line. Once the angles of the carbon brushes on both sides do not meet the 180° requirement, one carbon brush will contact one commutator and the other carbon brush will contact two commutators, resulting in poor ripple. However, due to machining accuracy reasons, it is difficult to ensure that the carbon brushes on both sides of the commutator are in a straight line (such as Figure 4 viewing angle).

[0026] It should be noted that: See Figure 4 In the initial stage of motor operation, when viewed from the horizontal angle of the commutator 3, the carbon brush body 2 and the commutator 3 are in point contact (at this time, along the longitudinal angle of the commutator, the carbon brush and the commutator are in line contact). Therefore, when the carbon brush angles on both sides of the commutator 3 meet 180°, the line formed by the contact points of the carbon brushes on both sides and the commutator in space is a straight line (in the following description, all are based on Figure 4 The perspective describes the positional relationship between the commutator 3 and the carbon brush).

[0027] Therefore, the present invention provides a brush holder, so that at the initial stage of motor operation, the carbon brushes on both sides of the commutator 3 are in contact with the commutator 3 at two points, and the two points on the carbon brushes on both sides form two straight lines in space, thereby changing the contact between the carbon brush and the commutator from one line to two lines. When the carbon brush leaves one commutator segment, it will not immediately contact the other commutator segment, thereby increasing the product's fault tolerance rate and improving the ripple performance of the ripple motor.

[0028] Example 1 This embodiment provides a brush holder for a DC motor. Figure 1 , Figure 2, specifically comprising: a wire 1, used to connect the internal circuit of the motor; a carbon brush body 2, connected to the motor through the wire 1, and a U-shaped opening groove 21 is provided on the side of the carbon brush body 2 that contacts the commutator 3, so that when the carbon brush body 2 part on one side of the commutator 3 contacts the adjacent commutator 3 piece, the motor outputs a stable ripple; the opening direction of the opening groove 21 faces the commutator 3.

[0029] It can be explained that the wire 1 is connected to the brush plate assembly in the motor by soldering; The structural design of the open groove 21 ensures that at the initial stage of the motor operation, each carbon brush body 2 has two contact points with the commutator 3 (in terms of the lateral angle of the commutator 3, at this time, in terms of the longitudinal angle of the commutator 3, each carbon brush body 2 is in contact with the commutator 3 in two straight lines); the contact state between the commutator 3 and the carbon brush bodies 2 on both sides is converted into two straight lines in space. When one of the straight lines leaves one commutator 3, it will not immediately contact the other commutator 3. Therefore, the generated ripples are more stable, reducing the requirements for product manufacturing precision.

[0030] More specifically, the opening groove 21 is opened along the height direction of the carbon brush body 2 to equally divide the surface of the carbon brush body 2 in contact with the commutator 3. It can be explained that the height of the opening groove 21 is the same as the height of the carbon brush body 2, so that the carbon brush body 2 and the commutator 3 are in contact with two surfaces of the same size and shape, and then when viewed from the lateral angle of the commutator 3, the carbon brush body 2 and the commutator 3 are in contact at two points.

[0031] In the specific implementation process, see Figure 1 , Figure 2 The contact surface between the carbon brush body 2 and the commutator 3 is two arc-shaped concave surfaces 22, and the two arc-shaped concave surfaces 22 are connected by the open groove 21; and in order to prevent the carbon brush body 2 from being damaged due to low strength caused by wear during continuous operation, both sides of the open groove 21 are connected to the arc-shaped concave surfaces 22 by a circular arc connecting surface 23, and the radius R of the circle where the circular arc connecting surface 23 is located is 0.4-0.6mm.

[0032] The two arc-shaped concave surfaces 22 form a first arc surface in space, and the arc of the first arc surface is smaller than the arc of the outer surface of the commutator 3; the radius R of the circle where the first arc surface is located is 5-5.2 mm.

[0033] In the specific implementation process, in order to reduce the contact area between the carbon brush body 2 and the commutator 3 in the initial operation of the motor and improve the initial noise of the motor, a plurality of protruding teeth 221 are provided on the arc-shaped concave surface 22 along its width direction, and the tooth groove width between adjacent teeth 221 is 0.4-0.6mm, and the depth of the tooth 221 is 0.095-0.2mm.

[0034] Since the carbon brush body 2 will gradually wear out during use, sharp parts will appear on the edge of the carbon brush body 2 in the later stage, resulting in low structural strength, and the surface roughness of the commutator 3 decreases, which is also easy to cause the sharp parts to break. Therefore, in the specific implementation process, the carbon brush body 2 also includes a first chamfered surface 24, and the first chamfered surface 24 is connected to the outer side of the arc-shaped concave surface 22. The design of the first chamfered surface 24 structure avoids the carbon brush body 2 from having sharp chamfers after running for a period of time, and reduces the influence of external stress on it during transportation and work. Furthermore, in order to improve the strength of the carbon brush body 2, the angle α between the plane formed by the straight lines on both sides of the arc-shaped concave surface 22 in the vertical direction and the first chamfered surface 24 is 130-140°.

[0035] It should be noted that one of the arc-shaped concave surfaces 22 is correspondingly connected to one of the first chamfered surfaces 24 .

[0036] Since the gap between the carbon brush body 2 and the brush box is small, in order to facilitate the installation of the carbon brush body 2 and the brush box, the upper end surface 25 of the carbon brush body 2 is provided with a second chamfered surface 26 and a connecting surface 27 connected in sequence on both sides along its length direction. The second chamfered surface 26 and the connecting surface 27 are connected to the commutator side through the first chamfered surface 24, and the angle β formed between the second chamfered surface 26 and the connecting surface 27 is 130-140° (see Figure 3 ); the upper end of the side wall of the carbon brush body 2 is vertically connected to the connecting surface 27. This structural design prevents burrs from being generated during the reproduction of the brush holder of the present invention, and prevents sharp parts from being damaged during assembly and falling into the motor.

[0037] Furthermore, the second chamfered surface 26 and the connecting surface 27 on one side close to the commutator 3 are both connected to the upper portion of the first chamfered surface on the same side.

[0038] In order to improve the effect and ensure the strength of the carbon brush body, the inner concave surface 211 of the opening groove 21 is a second arc surface with a diameter of 0.9-1.1mm; and in order to improve the wear resistance of the carbon brush body 2 (the wear depth after 30,000 cycles is just enough to complete the wear), the vertex of the second arc surface is 1.3-1.4mm away from the vertex of the first arc surface.

[0039] It can be explained that the width of the inner concave surface accounts for about 1 / 3 of the width of the carbon brush body 2 .

[0040] The brush holder structure of the present invention can effectively improve the motor ripple level and reduce the reliance on high manufacturing precision of the product without affecting the motor EMC level (referring to the electromagnetic interference level and electromagnetic immunity level) and noise performance. The design of the opening slot 21 increases the contact points between the carbon brush body 2 and the commutator 3, compensating for the defect that the carbon brush body 2 on both sides does not have a 180° tolerance caused by manufacturing.

[0041] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0042] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0043] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A brush holder for a DC motor, characterized in that: include A wire (1) is used to connect the internal circuit of the motor; A carbon brush body (2) is connected to the motor via the wire (1), and a U-shaped opening groove (21) is provided on a side of the carbon brush body (2) in contact with the commutator (3), so that when a portion of the carbon brush body (2) on one side of the commutator (3) contacts an adjacent commutator (3) piece, the motor outputs a stable ripple; The opening direction of the opening slot (21) faces the commutator (3).

2. A brush holder for a DC motor according to claim 1, characterized in that: The opening groove (21) is opened along the height direction of the carbon brush body (2) so as to evenly divide the surface of the carbon brush body (2) in contact with the commutator (3).

3. A brush holder for a DC motor according to claim 2, characterized in that: The contact surface between the carbon brush body (2) and the commutator (3) is two arc-shaped concave surfaces (22), and the two arc-shaped concave surfaces (22) are connected via the open groove (21); The two arc-shaped concave surfaces (22) form a first arc surface in space.

4. A brush holder for a DC motor according to claim 3, characterized in that: The arc angle of the first arc surface is smaller than the arc angle of the outer surface of the commutator (3).

5. A brush holder for a DC motor according to claim 4, characterized in that: The radius R of the circle where the first arc surface is located is 5-5.2 mm.

6. A brush holder for a DC motor according to claim 3, characterized in that: The arc-shaped concave surface (22) is provided with a plurality of protruding teeth (221) along its width direction, the tooth groove width between adjacent teeth (221) is 0.4-0.6 mm, and the depth of the teeth (221) is 0.095-0.2 mm.

7. A brush holder for a DC motor according to claim 6, characterized in that: The carbon brush body (2) further comprises a first chamfered surface (24), wherein the first chamfered surface (24) is connected to the outer side of the arc-shaped concave surface (22).

8. A brush holder for a DC motor according to claim 7, characterized in that: The upper end surface (25) of the carbon brush body (2) is provided with a second chamfered surface (26) and a connecting surface (27) connected in sequence on both sides along the length direction thereof, the second chamfered surface (26) and the connecting surface (27) are connected on a side close to the commutator via the first chamfered surface (24), and an angle β formed between the second chamfered surface (26) and the connecting surface (27) is 130-140°; The upper end of the side wall of the carbon brush body (2) is vertically connected to the connecting surface (27).

9. A brush holder for a DC motor according to claim 7, characterized in that: The second chamfered surface (26) and the connecting surface (27) on a side close to the commutator (3) are both connected to the upper part of the first chamfered surface.

10. A brush holder for a DC motor according to claim 3, characterized in that: The inner concave surface (211) of the opening groove (21) is a second arc surface with a diameter of 0.9-1.1 mm, and the distance between the vertex of the second arc surface and the vertex of the first arc surface is 1.3-1.4 mm.

Images