Anti-reverse commutator

Abstract

An anti-backflow commutator includes a bakelite powder substrate with a mounting hole at its center. Commutator segments are evenly distributed around the outer circumference of the substrate. Mica sheets are used for inter-segment insulation between adjacent commutator segments. Each commutator segment includes a commutator body with dovetail grooves around its bottom. The bottom surface of each dovetail groove is an upward-sloping surface, so that the bottom of the commutator body is dovetail-shaped in both the transverse and longitudinal sections. A copper foot is located at the bottom of the commutator body, with symmetrical mounting grooves on both sides. This invention achieves multi-directional anti-backflow and anti-torsion locking between the commutator segments and the substrate through a multi-dimensional dovetail groove structure. Combined with the multiple anchoring structure of the copper foot, it significantly improves the anti-backflow and anti-torsion capabilities of the commutator segments. The structure is reliable and suitable for high-speed, high-power motor applications.

Description

Technical Field

[0001] This utility model relates to the field of motor commutator technology, and in particular to an anti-reverse commutator. Background Technology

[0002] The commutator is a key component in rotating motors such as DC motors and AC series motors. Its function is to switch the direction of current in the armature winding, ensuring continuous unidirectional rotation of the motor. A commutator typically consists of a bakelite matrix and commutator segments embedded in its outer ring. The bonding strength between the commutator segments and the bakelite matrix directly affects the service life and reliability of the commutator. In existing technologies, to prevent the commutator segments from detaching from the matrix due to centrifugal force during high-speed rotation (i.e., the "reverse displacement" phenomenon), dovetail grooves are usually created at the bottom of the commutator segments to increase mechanical anchoring force. However, the traditional dovetail groove structure only forms a reverse connection in one direction. When the commutator operates under conditions of high temperature, high speed, or frequent start-stop, small gaps may still occur between the bakelite matrix and the commutator segments due to differences in thermal expansion coefficients and long-term vibration, leading to loosening or even detachment of the commutator segments. In addition, the existing commutator has a relatively simple connection structure between the copper feet and the base, which is not strong enough torsional resistance. Under the impact torque generated at the moment of motor start-up or commutation, the commutator segment is prone to circumferential micro-movement, which can lead to problems such as fatigue fracture of the welding point or uneven wear of the commutator segment. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an anti-backflow commutator with a simple structure, reasonable design, strong anti-backflow and anti-torsion capabilities of the commutator segments, and suitable for high-speed, high-power motor operating conditions.

[0004] The technical solution adopted by this utility model to solve its technical problem is: an anti-reverse commutator, including a bakelite powder substrate, wherein a mounting hole is opened in the center of the bakelite powder substrate, and commutator segments are uniformly arranged on the outer ring of the bakelite powder substrate along its circumferential direction. Mica sheets are provided between adjacent commutator segments for inter-segment insulation. Each commutator segment includes a commutator segment body, and dovetail grooves are respectively provided around the bottom of the commutator segment body. The bottom surface of each dovetail groove is an inclined surface that slopes from bottom to top, so that the bottom of the commutator segment body is dovetail-shaped in both the transverse and longitudinal sections. The bottom of the commutator segment body is provided with copper feet, and mounting grooves are symmetrically opened on both sides of the copper feet.

[0005] Preferably, the bottom surface of the dovetail groove is provided with at least one auxiliary anchoring groove along the length of the commutator body, and the cross-section of the auxiliary anchoring groove is trapezoidal.

[0006] Preferably, a wiring portion is provided at one upper end of the commutator body, and a wire bonding groove is formed on the top of the wiring portion along the length direction of the commutator body. The wire bonding groove has an overall U-shaped structure.

[0007] Preferably, the commutator body has a step that protrudes outward from the outer side of one end where the wiring portion is located.

[0008] Preferably, the longitudinal section of the copper foot is trapezoidal, and the longitudinal section of the groove is parallelogram-shaped.

[0009] Preferably, the trapezoidal structure of the copper foot has anti-rotation protrusions extending downward on both sides of the bottom edge. The anti-rotation protrusions are embedded in the bakelite powder matrix, and the outer wall of the anti-rotation protrusions is located on the same plane as the outer wall of the copper foot.

[0010] Preferably, a connecting piece is provided between the bottom of the commutator body and the copper foot, and the two sides of the connecting piece form a strip groove between the commutator body and the copper foot.

[0011] Preferably, the connecting piece has at least two fixing holes, and the connecting piece is further provided with at least one reinforcing rib extending along the length direction of the commutator body between two adjacent fixing holes.

[0012] Preferably, both ends of the connecting piece are provided with U-shaped fixing grooves, and the bakelite powder matrix is ​​provided with reinforcing rings in the fixing grooves on both sides. The reinforcing rings are metal rings or high-strength fiber-reinforced composite material rings, and the outer circumferential surface of the reinforcing rings is provided with circumferentially distributed protrusions.

[0013] The beneficial effects of this utility model are:

[0014] 1. Dovetail grooves are provided around the bottom of the commutator body, and the bottom surface of the grooves slopes from bottom to top, so that the bottom is dovetail-shaped in both the horizontal and vertical sections, forming a four-sided inverted "anchor claw" locking structure, which independently bears the tensile force in each direction, avoiding the cracking of the base caused by stress concentration in one direction.

[0015] 2. When microcracks appear at the root of the main dovetail groove due to thermal aging or fatigue, the auxiliary anchoring groove located at the deepest part of the groove can still maintain an intact inverted locking state due to its independent structural form, which prevents the commutator segment from suddenly flying off and provides safety redundancy for equipment maintenance.

[0016] 3. When subjected to circumferential impact torque, the groove at the top generates oblique resistance, and the anti-rotation boss at the end generates pile-type resistance, which transforms the torsional torque into uniform compressive stress on the base rather than shear stress, thus preventing the base from cracking due to shear stress concentration on a single cross section.

[0017] 4. During injection molding, the reinforcing ribs change the flow path of the bakelite powder, causing it to fill the fixing holes preferentially along the direction of the reinforcing ribs, thus avoiding incomplete filling or porosity defects. At the same time, the reinforcing ribs divide the connecting piece area into independent units. When microcracks occur in the matrix around a single fixing hole, the reinforcing ribs can prevent the cracks from spreading to adjacent areas.

[0018] 5. The protruding ridge increases the mechanical locking point between the reinforcing ring and the base. When rotating at high speed, the protruding ridge decomposes the radial expansion force into multiple circumferential tangential components, which are dispersed into the interior of the base to avoid stress concentration at the interface and prevent circumferential slippage of the reinforcing ring during long-term operation. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of an embodiment of the present utility model;

[0020] Figure 2 This is a utility model Figure 1 Enlarged view of point A;

[0021] Figure 3 This is a front view of the commutator segment of this utility model;

[0022] Figure 4 This is a side view of the commutator segment of this utility model.

[0023] In the diagram: 1. Bakelite powder substrate; 11. Mounting hole; 2. Commutator segment; 21. Commutator segment body; 211. Dovetail groove; 212. Auxiliary anchoring groove; 22. Copper foot; 221. Setting groove; 222. Anti-rotation boss; 23. Wiring part; 231. Soldering groove; 24. Step; 25. Connecting piece; 251. Strip groove; 252. Fixing hole; 253. Reinforcing rib; 254. Fixing groove; 3. Mica sheet; 4. Reinforcing ring; 41. Raised ridge. Detailed Implementation

[0024] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. Example

[0025] like Figures 1 to 4 The anti-reverse commutator shown includes a bakelite powder substrate 1, a mounting hole 11 is opened in the center of the bakelite powder substrate 1, and commutator segments 2 are uniformly arranged on the outer ring of the bakelite powder substrate 1 along its circumference. Mica sheets 3 are provided between adjacent commutator segments 2 for inter-segment insulation.

[0026] The commutator 2 includes a commutator body 21. Dovetail grooves 211 are provided around the bottom of the commutator body 21. The bottom surface of each dovetail groove 211 is an inclined surface that slopes upward from bottom to top. When cut from the horizontal (i.e. the width direction of the commutator 2) and the longitudinal (i.e. the length direction of the commutator 2) respectively, the bottom of the commutator body 21 presents a dovetail-shaped inverted shape. Traditional dovetail grooves 211 are usually only set on both sides (laterally) of the commutator segment 2, forming an anti-detachment structure in only one dimension. However, this utility model sets dovetail grooves 211 on all four sides of the commutator segment body 21, and the bottom of the groove is inclined inward, so that the commutator segment 2 forms an inverted locking with the bakelite powder matrix 1 in the radial, axial and circumferential directions. When the commutator rotates at high speed, the centrifugal force acts on the commutator segment 2 in all directions. The multi-dimensional dovetail groove 211 structure can evenly distribute the tension to the interior of the matrix, which significantly improves the anti-backflow capability. In the overspeed performance test, it is more than 2,000 revolutions higher than the traditional structure.

[0027] At least one auxiliary anchoring groove 212 is formed on the bottom surface of the dovetail groove 211 along the length of the commutator body 21. The cross-section of the auxiliary anchoring groove 212 is trapezoidal. The trapezoidal auxiliary anchoring groove 212 forms a second-level inverted locking structure inside the dovetail groove 211, i.e., a "groove within a groove" design. During injection molding, bakelite powder material first fills the dovetail groove 211 to form the first anchoring, and at the same time fills the auxiliary anchoring groove 212 to form the second anchoring. The double anchoring structure ensures that even if micro-cracks develop at the root of the dovetail groove 211 during long-term use, the auxiliary anchoring groove 212 can still maintain effective locking force, greatly improving the reliability of the connection between the commutator 2 and the substrate.

[0028] The bottom of the commutator body 21 is provided with a copper foot 22. The longitudinal section of the copper foot 22 is a trapezoidal structure that is wider at the top and narrower at the bottom. This trapezoidal structure itself forms a radial anti-disengagement buckle. The copper foot 22 has symmetrically opened mounting grooves 221 on both sides. The longitudinal section of the mounting grooves 221 is a parallelogram structure. After injection molding, the parallelogram mounting grooves 221 form an oblique mechanical interlock, which works together with the trapezoidal structure to further enhance the fixing effect of the copper foot 22 in the axial and circumferential directions.

[0029] To further enhance torsional resistance, anti-rotation protrusions 222 extend downwards from both sides of the trapezoidal bottom edge (i.e., the narrow side) of the copper foot 22. These anti-rotation protrusions 222 are embedded within the bakelite powder matrix 1, and their outer walls are on the same plane as the outer wall of the copper foot 22. This ensures that the matrix material can be evenly coated during injection molding, preventing stress concentration. The anti-rotation protrusions 222 are located at the very end of the copper foot 22, forming a "pile-type" anchoring structure. When the commutator segment 2 is subjected to a circumferential impact torque, the anti-rotation protrusions 222 and the parallelogram structure of the groove 221 work together at different axial heights to resist the torsional torque, effectively preventing the commutator segment 2 from fretting or rotating in the circumferential direction.

[0030] A connecting piece 25 is provided between the bottom of the commutator body 21 and the copper foot 22. A strip-shaped groove 251 is formed between the two sides of the connecting piece 25 and the commutator body 21 and the copper foot 22. During injection molding, the strip-shaped groove 251 is filled with the base material, forming a continuous longitudinal locking band, increasing the bonding area between the commutator 2 and the base material in the length direction. At least two fixing holes 252 are provided on the connecting piece 25. During injection molding, the fixing holes 252 are penetrated by the base material, forming "rivet-type" anchor points, further enhancing the radial fixing effect. At least one reinforcing rib 253 extending along the length of the commutator body 21 is also provided on the connecting piece 25 between two adjacent fixing holes 252. The reinforcing rib 253 improves the bending strength of the connecting piece 25 itself, preventing deformation of the connecting piece 25 under injection pressure or during use, and ensuring that the bonding between the fixing hole 252 and the base material remains stable.

[0031] Both ends of the connecting piece 25 are opened in the U-shaped fixing groove 254. The bakelite powder matrix 1 is embedded in the fixing groove 254 on both sides. The reinforcing ring 4 is embedded in both ends of the commutator as a whole, which plays a circumferential clamping role and effectively counteracts the radial expansion effect generated by centrifugal force. The reinforcing ring 4 is a metal ring or a high-strength fiber-reinforced composite material ring, and the outer circumferential surface of the reinforcing ring 4 is provided with circumferentially distributed protrusions 41. The structure of the protrusions 41 enhances the bonding strength between the reinforcing ring 4 and the bakelite powder matrix 1 and prevents the reinforcing ring 4 from sliding relative to each other when rotating at high speed.

[0032] A wiring portion 23 is provided at one upper end of the commutator segment body 21. A soldering groove 231 is formed on the top of the wiring portion 23 along the length of the commutator segment body 21. The soldering groove 231 has an overall U-shaped structure. The U-shaped soldering groove 231 facilitates the positioning and soldering of the winding wire ends. After soldering, the solder fills the U-shaped groove to form a strong mechanical and electrical connection. A step 24 protrudes outward from the outer side of the end of the commutator segment body 21 where the wiring portion 23 is located. This step 24 is embedded in the bakelite powder matrix 1 during injection molding to form an axial positioning and anti-rotation structure, further preventing the wiring portion 23 from shifting during welding or use.

[0033] This utility model significantly improves the bonding strength and torsional resistance between the commutator segment 2 and the bakelite powder matrix 1 through the synergistic effect of multiple technical means, including the dual anti-detachment structure formed by the multi-dimensional dovetail groove 211 and the auxiliary anchoring groove 212, the trapezoidal and parallelogram composite anchoring structure of the copper foot 22, the end anti-rotation boss 222, the reinforcing rib 253 and fixing hole 252 of the connecting piece 25, and the end reinforcing ring 4. It effectively prevents the occurrence of reverse displacement, extends the service life of the commutator, and is suitable for motors with high speed, high power and frequent start-stop conditions.

Claims

1. A reverse-flow commutator, comprising a bakelite powder substrate (1), wherein a mounting hole (11) is formed at the center of the bakelite powder substrate (1), and commutator segments (2) are uniformly arranged along the circumferential direction on the outer ring of the bakelite powder substrate (1), and mica sheets (3) are provided between adjacent commutator segments (2) for inter-segment insulation, characterized in that: The commutator segment (2) includes a commutator segment body (21). Dovetail grooves (211) are provided around the bottom of the commutator segment body (21). The bottom surface of each dovetail groove (211) is an inclined surface that slopes from bottom to top, so that the bottom of the commutator segment body (21) is dovetail-shaped in both the horizontal and vertical longitudinal sections. The bottom of the commutator segment body (21) is provided with copper feet (22). The copper feet (22) are symmetrically provided with mounting grooves (221) on both sides.

2. The anti-reverse commutator according to claim 1, characterized in that: The bottom surface of the dovetail groove (211) is provided with at least one auxiliary anchoring groove (212) along the length of the commutator body (21), and the cross-section of the auxiliary anchoring groove (212) is trapezoidal.

3. The anti-reverse commutator according to claim 1, characterized in that: The upper end of the commutator body (21) is provided with a wiring part (23), and the top of the wiring part (23) is provided with a wire bonding groove (231) along the length direction of the commutator body (21). The wire bonding groove (231) is U-shaped in general.

4. The anti-reverse commutator according to claim 3, characterized in that: The commutator body (21) has a step (24) protruding outward from the outer side of one end where the wiring part (23) is located.

5. The anti-reverse commutator according to claim 1, characterized in that: The longitudinal section of the copper foot (22) is trapezoidal, and the longitudinal section of the groove (221) is parallelogram.

6. The anti-reverse commutator according to claim 1, characterized in that: The trapezoidal structure of the copper foot (22) has anti-rotation protrusions (222) extending downward on both sides of the bottom edge. The anti-rotation protrusions (222) are embedded in the bakelite powder matrix (1). The outer wall of the anti-rotation protrusions (222) and the outer wall of the copper foot (22) are located on the same plane.

7. The anti-reverse commutator according to claim 1, characterized in that: A connecting piece (25) is provided between the bottom of the commutator body (21) and the copper foot (22), and a strip groove (251) is formed between the two sides of the connecting piece (25) and the commutator body (21) and the copper foot (22).

8. The anti-reverse commutator according to claim 7, characterized in that: The connecting piece (25) has at least two fixing holes (252), and the connecting piece (25) is also provided with at least one reinforcing rib (253) extending along the length direction of the commutator body (21) between two adjacent fixing holes (252).

9. The anti-reverse commutator according to claim 7, characterized in that: Both ends of the connecting piece (25) are opened in the fixing groove (254) with a U-shaped structure. The bakelite powder matrix (1) is provided with reinforcing rings (4) in the fixing grooves (254) on both sides. The reinforcing rings (4) are metal rings or high-strength fiber-reinforced composite material rings, and the outer circumferential surface of the reinforcing rings (4) is provided with convex ridges (41) distributed along the circumferential direction.

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