Multi-fastening-ring commutator for direct-current motor and direct-current motor

Abstract

The multi-fastening-ring commutator for the direct-current motor comprises a bakelite powder main body, a plurality of commutator segments and mica sheets are distributed on the circumference of the outer circle of the bakelite powder main body, and a lining is arranged in an inner hole of the bakelite powder main body; the commutator segment comprises a conductive main body, the rear part of the outer surface of the conductive main body is connected with a lifting platform, the inner surface of the conductive main body extends inwards to form a plurality of hook feet, each hook foot is provided with a fastening ring, and the inner surface of the conductive main body is a step surface with more than two stages. When the commutator with the multiple fastening rings is used in a high-power direct-current motor, the deformation of the commutator segments is reduced and controlled as much as possible when the commutator operates under the working conditions of high current and high rotating speed.

Description

Technical Field

[0001] The utility model relates to the technical field of brushed DC motors, in particular to a DC motor commutator and a DC motor. Background Art

[0002] Some high-power DC motors work under high current and wide speed range conditions. According to the working characteristics of DC motors:

[0003] On the one hand, when the motor is running, a large current will continue to pass through the commutator segments. Under the action of this large current, the temperature rise of the commutator is relatively high. High temperature will cause the strength of the insulating material in the commutator to decrease. The larger the working current, the higher the temperature rise of the commutator and the lower the strength of the insulating material in the commutator.

[0004] On the other hand, the motor will generate centrifugal force during operation, which will directly act on the commutator segments, causing them to deform. Since the centrifugal force is related to the motor speed and the commutator diameter, the higher the motor speed and the larger the commutator diameter, the greater the centrifugal force on the commutator, and the easier it is for the commutator segments to deform.

[0005] After the strength of the insulating material in the commutator is reduced and the commutator segments are deformed, the commutator segments on the commutator will be uneven. When the motor is running, the relative movement between the brushes and the commutator will cause the brushes to jump and generate sparks. The sparks will burn the contact surface between the brushes and the commutator, reducing the service life of the motor.

[0006] In order to solve the commutation spark problem caused by commutator deformation in these high-power DC motors, the commutator is designed as a sleeve and nut tightened installation structure. This structure has stable performance, but high cost and low production efficiency. In order to save production costs and improve production efficiency, the commutator is generally designed as a plastic pressure filling structure. The filler is generally made of high-temperature resistant bakelite powder material. The commutator segments in the commutator are generally designed as a dovetail groove structure, and a fastening ring is installed on the dovetail groove to prevent the commutator from deforming.

[0007] The structural design of the commutator segment is a key factor affecting whether the commutator segment is deformed. How to minimize the influence of centrifugal force on the commutator segment under the condition of appropriate current density has become an urgent problem to be solved.

[0008] Existing solutions:

[0009] The commutator segments are designed as a parallel double dovetail structure (such as Fig.12 As shown in the figure), a weight-reducing hole A' is designed in the middle of the commutator segment, and a fixing ring can be installed on each of the dovetail grooves on both sides of the commutator segment.

[0010] When the motor runs at high current and high speed, the conductive body in the middle part of the commutator (seen from the axial direction) is prone to deformation, causing the motor spark to become larger. Summary of the invention

[0011] The utility model aims to solve the problem that when the existing plastic pressed commutator is used in a high-power DC motor, in order to ensure that the deformation of the commutator segments is minimized and controlled when the commutator operates under high current and high speed conditions, a multi-fastening ring commutator for a DC motor is proposed.

[0012] The utility model also provides a DC motor.

[0013] The technical solution of the utility model is: a multi-fastening ring commutator for a DC motor, comprising a bakelite powder main body, a plurality of commutator segments and mica sheets distributed on the circumference of the outer circle of the bakelite powder main body, and a bushing in the inner hole of the bakelite powder main body; the commutator segments comprise a conductive main body, the rear part of the outer surface of the conductive main body is connected to a raised platform, a plurality of hooks are extended inwardly from the inner surface of the conductive main body, a fastening ring is installed at each hook, and the inner surface of the conductive main body presents a stepped surface of two or more levels so that the thickness of the commutator segments forms a thick to thin structure from the raised platform side to the other side.

[0014] The outer surface of the conductive body is a plane, and the rear of the plane is connected to the raised platform.

[0015] The plane where the ends of the hook feet are located is a stepped plane; the hook feet include end hook feet arranged at the front and rear ends, and a middle hook foot located between the end hook feet at the front and rear ends.

[0016] The hook foot is one or more of L-shaped, T-shaped and dovetail-shaped.

[0017] The commutator segments and mica sheets are alternately arranged in a circular ring shape. The surface of the bushing is evenly distributed with tooth-like structures.

[0018] The inner surface of the conductive body has two or more step surfaces, so that the thickness of the commutator segment forms a structure from thick to thin from the elevated platform side to the other side.

[0019] The inner surface of the conductive body is in the form of three-step surfaces, including a high step surface C at the rear, a middle step surface B at the middle, and a low step surface A at the front.

[0020] The high step surface and the middle step surface are both arranged with hooks of different heights, there are at least two high hooks on the high step surface, at least one low hook on the high step surface, at least one high hook on the middle step surface, at least one low hook on the middle step surface, the plane where the ends of the high hooks on the high step surface are located is A3, the plane where the ends of the low hooks on the high step surface and the ends of the high hooks on the middle step surface are located is A2, the plane where the ends of the low hooks on the middle step surface are located is A1, and A3, A2, and A1 form three-level step surfaces.

[0021] A multi-fastening ring commutator for a DC motor comprises a bakelite powder body, a plurality of commutator segments and mica sheets distributed on the outer circumference of the bakelite powder body, and a bushing is arranged in the inner hole of the bakelite powder body; the commutator segments comprise a conductive body, the outer surface of the conductive body is a plane, the rear part of the plane is connected to a raised platform, a plurality of hooks are extended inwardly from the inner surface of the conductive body, each hook is provided with a fastening ring, the inner surface of the conductive body is a plane, and the plane where the ends of the hooks are located is a stepped plane.

[0022] A DC motor comprises the commutator as described above.

[0023] The beneficial effects of the utility model are:

[0024] 1) The conductive body of the commutator segment is step-shaped

[0025] In a DC motor, after the motor is powered on, the current flows from the brushes into the commutator segments, and then flows into the components from the commutator segment's raised platform. Therefore, from an axial point of view, the actual current in the commutator segment's conductive body increases linearly from 0 from the opposite side of the raised platform to the side of the raised platform. The commutator segment's conductive body is designed to be stepped, and the thickness of the commutator segment decreases from thick to thin from the side of the raised platform to the other side. This not only reasonably guarantees the current density of the commutator segment, but also greatly reduces the overall weight of the commutator segment, reduces the centrifugal force on the commutator segment, and provides effective space for the step structure design with multiple hooks.

[0026] 2) The commutator segment is designed with more than two hooks and is distributed in a step-like manner

[0027] More than two hooks are distributed in a step-like manner from the middle of the commutator segment to both sides, which provides space feasibility for the installation of multiple fastening rings. The increase in the number of fastening rings allows the entire commutator segment to be fastened (the commutator segment can be fastened by the fastening ring along the axial direction), greatly increasing the fastening degree of the commutator segment, thereby reducing the degree of deformation of the commutator segment after heat and force (centrifugal force). The multiple fastening rings set up improve the mechanical properties and overall strength of the commutator, thereby improving the reliability of the commutator. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of the commutator of the utility model;

[0029] Figure 2 yes Figure 1 Side view of

[0030] Figure 3 yes Figure 1 Schematic diagram of the appearance;

[0031] Figure 4 This is the main view of the mica sheet;

[0032] Figure 5 It is a schematic diagram of the structure of the bushing;

[0033] Figure 6 is a side view of the commutator segment;

[0034] Figure 7 It is the front view of the commutator segment;

[0035] Figure 8 It is a schematic diagram of the hook structure of the commutator segment;

[0036] Fig. 9 This is the second structural diagram of the commutator segment ("L" shaped hook);

[0037] Fig.10 This is the third structural diagram of the commutator segment (“∏” shaped hook);

[0038] Fig.11 This is the fourth structural diagram of the commutator segment;

[0039] Fig.12 It is a schematic diagram of the existing commutator segment structure. DETAILED DESCRIPTION

[0040] Figure 1-6 In the utility model, the present invention includes a bakelite powder body 1, a commutator segment 2, a mica sheet 3, a bushing 4, and a fastening ring 5. The multi-fastening ring commutator includes a bakelite powder body 1, a plurality of commutator segments 2 and mica sheets 3 distributed on the outer circumference of the bakelite powder body, a bushing 4 in the inner hole of the bakelite powder body, and two or more fastening rings 5 ​​installed on the commutator segment hooks. The multi-fastening ring commutator is formed by fixing the commutator segment, mica sheet, bushing and fastening ring together through the plastic pressing process of bakelite powder. The commutator segment 2 includes five hooks 23, a commutator segment conductive body 22 and a riser 21. The bottom end of the commutator segment conductive body 22 is axially stepped. The riser 21 can be included in the commutator segment conductive body 22.

[0041] During processing: the multi-fastening ring commutator is positioned by a fixture, the commutator segments 2 and the mica sheets 3 are adjacent to each other and evenly distributed in a circular ring shape, and then the fastening rings 5 ​​and bushings 4 are installed, the bakelite powder body 1 is filled, and then the bakelite powder body 1, the commutator segments 2, the mica sheets 3, the bushings 4, and the fastening rings 5 ​​are fastened together through a plastic pressing process.

[0042] Figure 7-8In the figure, the inner surface of the conductive body 22 presents three-level step surfaces, including a high step surface C at the rear, a middle step surface B at the middle, and a low step surface A at the front. Hooks of different heights are arranged on the high step surface and the middle step surface. There are at least two high hooks on the high step surface, at least one low hook on the high step surface, at least one high hook on the middle step surface, and at least one low hook on the middle step surface. The plane where the end of the high hook 231 on the high step surface is located is A3, the plane where the end of the low hook 232 on the high step surface and the end of the high hook on the middle step surface are located is A2, and the plane where the end of the low hook 233 on the middle step surface is located is A1. A3, A2, and A1 present three-level step surfaces, and the plane where the end of the hook is located is distributed from high to low in a step-like manner from the middle of the commutator segment to both sides.

[0043] The commutator segment 2 includes a hook 23, a commutator segment conductive body 22 and a raised platform 21. The hook 23 is in a "∏" shape, an "L" shape, or a "T" shape. Fig. 9 The hook foot is in a "∏" shape (such as Fig.10 ).

[0044] Fig.11 In the figure, the outer surface of the conductive body 22 is a plane, the rear part of the plane is connected to the raised platform 21, and a plurality of hooks are extended inward from the inner surface of the conductive body 22, each hook is provided with a fixing ring 5, the inner surface of the conductive body 22 is a plane, and the plane where the ends of the hooks are located is distributed in a step-like manner from high to low from the middle of the commutator segment to both sides.

Claims

1. A multi-fastening ring commutator for a DC motor, characterized in that: It comprises a bakelite powder body (1), a plurality of commutator segments (2) and mica sheets (3) distributed around the outer circumference of the bakelite powder body, and a bushing (4) in the inner hole of the bakelite powder body; the commutator segments (2) comprise a conductive body (22), the outer surface of the conductive body (22) is connected to a raised platform (21) at the rear, the inner surface of the conductive body (22) extends inwardly with a plurality of hooks, each hook being provided with a fixing ring (5), and the inner surface of the conductive body (22) presents a stepped surface of at least two levels.

2. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The outer surface of the conductive body (22) is a plane, and the rear portion of the plane is connected to the raised platform (21).

3. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The plane where the ends of the hook feet are located is a stepped plane; the hook feet include end hook feet arranged at the front and rear ends, and a middle hook foot located between the end hook feet at the front and rear ends.

4. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The hook foot is one or more of L-shaped, T-shaped and dovetail-shaped.

5. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The commutator segments (2) and the mica sheets (3) are alternately arranged in a circular ring shape; and the surface of the bushing (4) is evenly distributed with tooth-like structures.

6. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The inner surface of the conductive body (22) is a stepped surface of more than two levels, so that the thickness of the commutator segments forms a structure that gradually becomes thinner from the raised platform side to the other side.

7. The multi-fastening ring commutator for a DC motor according to claim 1, characterized in that: The inner surface of the conductive body (22) is in the form of three-stepped surfaces, including a high-stepped surface C located at the rear, a middle-stepped surface B located in the middle, and a low-stepped surface A located at the front.

8. The multi-fastening ring commutator for a DC motor according to claim 7, characterized in that: The high step surface and the middle step surface are both provided with hooks of different heights. There are at least two high hooks on the high step surface and at least one low hook on the high step surface. There is at least one high hook on the middle step surface and at least one low hook on the middle step surface. The plane where the ends of the high hooks (231) on the high step surface are located is A3, the plane where the ends of the low hooks (232) on the high step surface and the ends of the high hooks on the middle step surface are located is A2, and the plane where the ends of the low hooks (233) on the middle step surface are located is A1. A3, A2, and A1 form three-level step surfaces.

9. A multi-fastening ring commutator for a DC motor, characterized in that: The invention comprises a bakelite powder body (1), a plurality of commutator segments (2) and mica sheets (3) distributed around the outer circumference of the bakelite powder body, and a bushing (4) provided in the inner hole of the bakelite powder body; the commutator segments (2) comprise a conductive body (22), the outer surface of the conductive body (22) being a plane, the rear of the plane being connected to a raised platform (21), the inner surface of the conductive body (22) extending inwardly with a plurality of hooks, each hook being provided with a fixing ring (5), the inner surface of the conductive body (22) being a plane, and the plane where the ends of the hooks are located being a stepped plane.

10. A DC motor, characterized in that: It comprises the commutator as claimed in any one of claims 1 to 9.

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