A micro commutator

Abstract

The utility model discloses a micro commutator, including bakelite powder and the multiple commutator plates of setting around the outside of bakelite powder, the outside of bakelite powder is provided with the separation groove of separating adjacent commutator plate, the commutator plate include arc sheet body and set up in the hook foot part of arc sheet body first end, the first end of arc sheet body is located the both sides of hook foot part and is provided with at least one first grip part, the inboard of second end of arc sheet body is provided with at least one second grip part, the first grip part and second grip part all are to the inwardly inclined shape, and extend to the first end direction of arc sheet body, the first grip part and second grip part embed to the inside of bakelite powder, can be realized in the smaller space through setting first grip part and second grip part on commutator and guarantee the combination intensity between commutator and bakelite powder, make bakelite powder have higher tension to commutator.

Description

Technical Field

[0001] This utility model relates to the field of motor commutator technology, specifically a miniature commutator. Background Technology

[0002] Commutators are crucial components of brushed motors, and they are also used in micro-commutator systems in devices such as mobile phones, tablets, and laptops, as well as in automotive systems like electric seat adjustments, window lifts, windshield wipers, and car heaters. Furthermore, they are found in small medical devices such as dental handpieces, miniature massagers, and micro-pumps in medical equipment. Due to the small size of micro-commutators, both the bakelite powder and the commutator segments located outside the bakelite powder are also relatively small. This presents a challenge in designing the bonding connection between the bakelite powder and the commutator segments. Therefore, a commutator segment structure that ensures strong bonding between the bakelite powder and the commutator segments and is suitable for micro-commutators is needed to meet the application requirements of micro-commutators. Utility Model Content

[0003] This invention provides a miniature commutator that solves the technical problem that the commutator segment structure of existing conventional commutators is difficult to meet the usage requirements of miniature commutators.

[0004] To achieve the above objectives, this utility model provides the following technical solution: a miniature commutator, comprising bakelite powder and a plurality of commutator segments arranged around the outer side of the bakelite powder. The outer side of the bakelite powder is provided with a separating groove that separates adjacent commutator segments. Each commutator segment includes an arc-shaped body and a hook foot portion disposed at a first end of the arc-shaped body. At least one first gripping portion is disposed on both sides of the hook foot portion at the first end of the arc-shaped body. At least one second gripping portion is disposed on the inner side of the second end of the arc-shaped body. Both the first and second gripping portions are inclined inwards and extend towards the first end of the arc-shaped body. The first and second gripping portions are embedded inside the bakelite powder. By providing the first and second gripping portions on the commutator segments, the bonding strength between the commutator segments and the bakelite powder can be ensured within a relatively small space, giving the bakelite powder a higher tension force on the commutator segments.

[0005] Preferably, the angle between the first gripping part and the second gripping part and the arc-shaped sheet is 25°. Because the diameter of the bakelite powder is relatively small, the 25° tilt angle can satisfy the formation of sufficient tension between the commutator and the bakelite powder.

[0006] Preferably, the thickness of the second gripping part is half the thickness of the first gripping part, so that the second gripping part can be embedded deeper into the bakelite powder, increasing the tensile strength of the commutator segment.

[0007] Preferably, the hook portion includes a root extending along the length of the commutator segment and a bent portion connected to the root. The root is embedded in bakelite powder, which can increase the bonding area between the commutator segment and the bakelite powder and increase the tension.

[0008] Preferably, the first gripping part, the second gripping part, the hook foot part, and the arc-shaped sheet are integrally stamped and formed, and the first gripping part and the second gripping part are formed by bending after stamping and forming. The process is simple, no welding is required, and the overall strength is high.

[0009] Compared with the prior art, the beneficial effects of this utility model are:

[0010] By setting a first gripping part and a second gripping part on the commutator segment, the bonding strength between the commutator segment and bakelite powder can be guaranteed in a relatively small space, so that the bakelite powder has a higher tension force on the commutator segment, preventing the product from deforming or loosening between segments due to centrifugal force when running at high speed. This solves the technical problem that the existing conventional commutator segment structure is difficult to meet the usage requirements of micro commutators. Attached Figure Description

[0011] Figure 1 This is the main view of the present invention.

[0012] Figure 2 This is a three-dimensional structural diagram of the commutator segment of this utility model;

[0013] Figure 3 This is a front view structural diagram of the commutator segment of this utility model.

[0014] Figure label:

[0015] 1. Commutator segment, 11. Hook foot, 12. First gripping part, 13. Second gripping part, 14. Bending part, 15. Root, 2. Bakelite powder, 3. Divider groove, 10. Arc-shaped piece. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0017] like Figure 1-3As shown, this utility model addresses the technical problem that the commutator segment structure of existing conventional commutators is difficult to meet the usage requirements of miniature commutators, and provides the following technical solution: A miniature commutator includes bakelite powder 2 and a plurality of commutator segments 1 arranged around the outer side of the bakelite powder 2. The outer side of the bakelite powder 2 is provided with a separating groove 3 that separates adjacent commutator segments 1. Each commutator segment 1 includes an arc-shaped body 10 and a hook foot portion 11 disposed at the first end of the arc-shaped body 10. At least one hook foot portion 11 is provided on both sides of the first end of the arc-shaped body 10. A first gripping part 12 is provided, and at least one second gripping part 13 is provided on the inner side of the second end of the arc-shaped plate 10. Both the first gripping part 12 and the second gripping part 13 are inclined inward and extend towards the first end of the arc-shaped plate 10. The first gripping part 12 and the second gripping part 13 are embedded in the interior of the bakelite powder 2. By providing the first gripping part 12 and the second gripping part 13 on the commutator 1, the bonding strength between the commutator 1 and the bakelite powder 2 can be guaranteed in a relatively small space, so that the bakelite powder has a higher tension force on the commutator 1.

[0018] Motors adapted to miniature commutators (such as mobile phone vibration motors and dental handpiece motors) often operate at high speeds of 8000-15000 rpm, making them prone to separation from the bakelite powder due to centrifugal force. In this embodiment, the first gripping part 12 and the second gripping part 13 are anchored at both ends and embedded with bakelite powder 2, increasing the radial tension force of the bakelite powder 2 on the commutator segment 1 to 60-80N, which can resist the centrifugal force at a speed of 15000 rpm. The radial displacement of the commutator segment 1 is controlled within 0.01mm, avoiding excessive motor sparking and commutation failure caused by loosening between segments. To address the space constraints of the miniature commutator, the gripping part adopts an inwardly inclined and short-sized structure, eliminating the need for additional radial space. At the same time, the embedding depth reaches 1 / 3 to 1 / 2 of the radial dimension of the bakelite powder, achieving a mechanical anchoring effect within a minimal space. After the first gripping part 12 and the second gripping part 13 are embedded in the bakelite powder 2, relative sliding between the commutator segment and the bakelite powder can be avoided, reducing bakelite powder wear caused by friction.

[0019] Specifically, there are three commutator segments 1, which can evenly distribute current. They are made of H62 brass, and the bakelite powder 2 is made of phenolic resin-based bakelite powder. After molding, the overall outer diameter is 6mm and the inner diameter is 2mm. The radius of the arc-shaped segment 10 is 3mm, the central angle is 120°, and the width of its first end is 4mm, and the width of its second end is also 4mm. The first gripping part 12 is specifically provided on each side of each hook leg 11, with a length of 2mm and a width of 1mm, embedded in the bakelite powder to a depth of 1.5mm. The second gripping part 13 is provided on each commutator segment, with a length of 1.8mm and a width of 1mm, embedded in the bakelite powder 2 to a depth of 1.2mm. Furthermore, the thickness of the second gripping part 13 is half the thickness of the first gripping part 12, allowing the second gripping part 13 to embed deeper into the bakelite powder 2, increasing the tensile strength of the commutator segment 1. For example, the thickness of the first gripping part 12 is 0.4mm, and the thickness of the second gripping part 13 is 0.2mm.

[0020] In this embodiment, the angle between the first gripping part 12 and the second gripping part 13 and the arc-shaped sheet 10 is 25°. Because the diameter of the bakelite powder 2 is relatively small, the 25° inclination angle can ensure sufficient tension between the commutator 1 and the bakelite powder 2. Specifically, if the angle is less than 25°, the inclination of the first gripping part 12 and the second gripping part 13 is too gentle, and the binding constraint of the bakelite powder 2 on the gripping part after curing is insufficient. At a speed of 12000 rpm, the gripping part is prone to slipping out of the bakelite powder 2. If the angle is greater than 25°, the inclination of the first gripping part 12 and the second gripping part 13 is too steep, and air bubbles or voids are easily formed at the root of the first gripping part 12 and the second gripping part 13 when the bakelite powder 2 is filled, resulting in a decrease in bonding strength. The 25° angle has been verified through comparative testing to ensure that the bakelite powder filling is sufficiently full, and is the optimal angle.

[0021] In this embodiment, the hook foot portion 11 includes a root portion 15 extending along the length direction of the commutator segment 1 and a bent portion 14 connected to the root portion 15. The root portion 15 is embedded in the bakelite powder 2, which can increase the contact area between the commutator segment 1 and the bakelite powder 2, and increase the tension force. After the root portion 15 is embedded in the bakelite powder, the contact area between the commutator segment and the bakelite powder is increased, especially the lateral contact area, which can resist the electromagnetic lateral force when the motor winding is energized and avoid poor contact between the winding and the hook foot. The bent portion 14 is used to wind the motor winding. After the root portion 15 is embedded in the bakelite powder, the fixing rigidity of the hook foot portion is increased. When winding the winding, the hook foot portion does not wobble, the welding point does not have a poor weld, ensuring stable current conduction and reducing commutation sparks.

[0022] In this embodiment, the first gripping part 12, the second gripping part 13, the hook foot part 11, and the arc-shaped plate 10 are integrally stamped structures. The first gripping part 12 and the second gripping part 13 are formed by bending after stamping. The process is simple, no welding is required, and the overall strength is high. Specifically, integral stamping avoids welding, and the size consistency is achieved during mass production, which is suitable for the precision assembly requirements of micro commutators. The three commutator segments 1 are integrally formed during stamping, then wound into a ring, and pressed together with bakelite powder 2. Then, grooves are cut on the outer side of the integrally formed commutator segments 1 to form a partition groove 3, which separates the three commutator segments 1 to form the finished commutator.

[0023] As one specific manufacturing process scheme in this embodiment:

[0024] 1. Pre-treatment of billet: Take H62 brass strip, put it into an annealing furnace, keep it at 300℃ for 1 hour, and let it cool naturally to room temperature to reduce hardness and facilitate stamping;

[0025] 2. Precision stamping: The annealed strip is fed into the punch press and the three commutator segments 1 are stamped into an arc-shaped sheet body 10, hook root 15, first gripping part prototype (unbent), and second gripping part prototype (unbent) in one go using a die. The stamping speed is 10 times / min, and the waste material is blown away with compressed air.

[0026] 3. Bending of gripping parts: The stamped commutator segments are fed into a CNC bending machine. The first gripping part is bent to 25°, and then the second gripping part is bent to 25°. After bending, the angle and position are checked with an optical image instrument. Defective products (deviation > 0.01mm) are rejected.

[0027] 4. Cleaning and drying: Place the qualified commutator segments into an ultrasonic cleaner, clean with ethanol solution for 5 minutes to remove oil stains, and then put them into an oven to dry for later use.

[0028] 5. Preparation of pressing mold: Use stainless steel mold with 3 commutator positioning slots inside the mold. Preheat the mold to 150℃ and keep it at that temperature for 20 minutes.

[0029] 6. Commutator segment positioning: The three commutator segments 1 are wound into a ring and placed into the positioning groove of the mold to ensure that: ① the arc-shaped segments fit against the inner wall of the mold; ② the first gripping part and the second gripping part face the center of the mold; ③ the root of the hook 15 is embedded in the root groove of the mold, and the bent part 14 extends out of the mold.

[0030] 7. Bakelite powder filling and molding: Take phenolic resin Bakelite powder and fill it evenly into the mold cavity. Then send the mold into the hydraulic press, apply a pressure of 5MPa, and hold the pressure for 10 minutes.

[0031] 8. Curing and demolding: The molded mold is sent into a curing oven (160℃, keep warm for 30 minutes) to completely cure the bakelite powder. Then it is allowed to cool naturally to room temperature. Finally, the mold is lubricated with a release agent and slowly demolded to obtain a miniature commutator blank.

[0032] 9. Trimming: Cut grooves on the outer side of the one-piece commutator segment 1 to form a partition groove 3, separating the three commutator segments 1. Lightly sand the commutator surface with sandpaper to remove burrs.

[0033] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0034] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A miniature commutator, comprising bakelite powder (2) and a plurality of commutator segments (1) arranged around the outer side of the bakelite powder (2), wherein the outer side of the bakelite powder (2) is provided with a separating groove (3) that separates adjacent commutator segments (1), characterized in that, The commutator (1) includes an arc-shaped plate body (10) and a hook foot (11) disposed at the first end of the arc-shaped plate body (10). At least one first gripping part (12) is disposed on both sides of the hook foot (11) at the first end of the arc-shaped plate body (10). At least one second gripping part (13) is disposed on the inner side of the second end of the arc-shaped plate body (10). The first gripping part (12) and the second gripping part (13) are both inclined inward and extend toward the first end of the arc-shaped plate body (10). The first gripping part (12) and the second gripping part (13) are embedded in the interior of the bakelite powder (2).

2. The miniature commutator according to claim 1, characterized in that: The angle between the first gripping part (12) and the second gripping part (13) and the arc-shaped sheet (10) is 25°.

3. The miniature commutator according to claim 2, characterized in that: The thickness of the second gripping part (13) is half the thickness of the first gripping part (12).

4. The miniature commutator according to claim 1, characterized in that: The hook portion (11) includes a root portion (15) extending along the length direction of the commutator segment (1) and a bent portion (14) connected to the root portion (15), wherein the root portion (15) is embedded in bakelite powder (2).

5. The miniature commutator according to any one of claims 1-4, characterized in that: The first gripping part (12), the second gripping part (13), the hook foot part (11) and the arc-shaped sheet (10) are integrally stamped structures, and the first gripping part (12) and the second gripping part (13) are formed by bending after stamping.

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