Plastic shell motor structure

Abstract

The utility model belongs to the technical field of brushless motors, in particular to a plastic shell motor structure, which comprises a rotor, a stator and a plastic shell integrally formed by injection molding, the radial section of the plastic shell is W-shaped, and the plastic shell comprises an outer shell part and an isolation part which completely isolate the rotor from the stator. An opening for assembling the rotor and the stator is formed in one side, opposite to the isolation part, of the shell part; when the stator and the rotor are fixed by the plastic shell, the stator and the rotor are separated, due to the rigid design of the plastic shell, accurate positioning of the stator and the rotor can be ensured, uniform air gaps between the stator and the rotor are ensured, and vibration, noise and efficiency reduction caused by eccentricity are avoided; the plastic shell can enhance the insulation grade and can meet the double insulation design, and the power can be higher under the same condition; even if more enameled wires are wound on the stator to increase the power of the motor, the stator still meets the safety requirement of the electrical clearance, so that the motor can safely operate under higher power.

Description

Technical Field

[0001] This utility model belongs to the field of brushless motor technology, specifically relating to a plastic-shell motor structure. Background Technology

[0002] Brushless motors are high-efficiency electric motors based on electronic commutation technology. Their development can be traced back to the technological bottlenecks of traditional brushed motors in the mid-20th century. Traditional brushed motors achieve current direction switching through mechanical brushes and a commutator, but suffer from problems such as brush wear, high electromagnetic interference, and limited efficiency. With breakthroughs in power electronics technology, permanent magnet materials, and microprocessor control, brushless motors employ Hall effect sensors or sensorless algorithms to adjust the winding current phase in real time through a controller, achieving a leap from mechanical commutation to electronic commutation and significantly improving reliability and energy conversion efficiency.

[0003] Traditional brushless motors use a double-end support structure where the rotor is directly fixed by a metal shell and two end caps, such as... Figure 1 As shown, the bearings 500 are fixed in the two front and rear end covers 400, and the rotor is rotatably mounted in the end covers 400 via the two bearings 500. The stator 200 is assembled in the metal housing 100. This structure has the following defects:

[0004] 1. Machining errors can easily cause air gap non-uniformity > 0.1 mm, which can trigger electromagnetic vibration (fundamental frequency is the product of pole pair number and rotational speed);

[0005] 2. The cumulative tolerance of multi-component assembly affects the effect of rotor dynamic balancing (dynamic balancing grade G6.3 is selected).

[0006] To address the aforementioned problems, this application proposes a plastic-cased motor structure. Utility Model Content

[0007] To address the aforementioned problems in the existing technology, this utility model provides a plastic shell motor structure that is lightweight, noise-reducing, durable, and cost-effective.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a plastic shell motor structure, including a rotor and a stator, including an integrally injection-molded plastic shell, the radial cross-section of the plastic shell being "W" shaped, the plastic shell including an outer shell portion and an isolation portion that completely isolate the rotor and the stator, an opening for assembling the rotor and the stator being provided on opposite sides of the outer shell portion and the isolation portion, a support rib for supporting the outer side of the stator being formed on the inner side of the isolation portion, and an airflow gap being provided between the inner side of the stator and the isolation portion.

[0009] As a preferred embodiment of the present invention, a first end cover is installed on the opening on one side of the isolation part, and a rotating output shaft is provided between the isolation part and the first end cover. The rotor is installed outside the output shaft and is wrapped by the isolation part and the first end cover.

[0010] As a preferred technical solution of this utility model, the outer shell has an opening on one side and a second end cap is provided. The center of the second end cap is also formed with a groove that axially fits into the end of the isolation part. The outer shell, the isolation part and the second end cap form a wrap around the stator.

[0011] As a preferred embodiment of this utility model, the output shaft is externally fixed with the inner rings of a first bearing and a second bearing, the outer end of the first bearing is fixed to the first end cover, and the outer ring of the second bearing is fixed to the bottom of the inner side of the isolation part.

[0012] As a preferred embodiment of this utility model, the rotor and stator are coaxial and located in the same plane.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. When fixing the stator and rotor with a plastic shell, the stator and rotor are separated. Due to the rigid design of the plastic shell, the stator and rotor can be accurately positioned, ensuring that the air gap between the stator and rotor is uniform and avoiding vibration, noise and efficiency reduction caused by eccentricity.

[0015] 2. The plastic shell can enhance the insulation level and meet the requirements of double insulation design, and under the same conditions, the power can be increased; even when the stator is wound with more enameled wire to increase the motor power, it still meets the safety requirements of electrical clearance, so that the motor can operate safely at higher power.

[0016] 3. The elastic properties of plastic can absorb vibrations caused by electromagnetic forces or mechanical imbalances, and compared with traditional metal casings, it can reduce high-frequency noise;

[0017] 4. The plastic shell can prevent dust, liquid or chemical substances from entering the stator-rotor gap, and can also improve corrosion resistance. The axial ribs on the plastic shell are conducive to heat dissipation and extend the motor life.

[0018] 5. Plastic is lighter than metal. For the same size and shape of housing, the weight of a plastic housing can be reduced by 30%-50%, thereby reducing the overall weight of the motor.

[0019] 6. Plastic parts can be manufactured efficiently through injection molding, and are easy to mold into complex geometries, simplifying the assembly process and thus reducing processing costs. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a schematic diagram of the existing technology;

[0022] Figure 2 This is a schematic diagram of the structure of this utility model;

[0023] Figure 3 This is a schematic diagram of the external structure of this utility model;

[0024] In the diagram: 1. Plastic shell; 101. Outer shell; 102. Isolation part; 2. First end cover; 3. Output shaft; 4. Rotor; 5. Second end cover; 6. Stator; 7. Support rib; 8. First bearing; 9. Second bearing. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] Example

[0027] Please see Figure 2-3 This utility model provides the following technical solution: a plastic shell motor structure, including a rotor 4 and a stator 6, including an integrally injection-molded plastic shell 1. The plastic can be PA66+glass fiber reinforced material, extruded or injection molded, or thermosetting material BMC, injection or compression molded, etc. The plastic shell 1 is the main insulation, withstanding AC3000V / 1min, and 0.25mm insulating paper can be placed inside the outer shell 101. The radial cross-section of the plastic shell 1 is "W" shaped. The plastic shell 1 includes... The rotor 4 and stator 6 are completely isolated by the outer casing 101 and the isolation section 102. Compared with metal, plastic is used in the case of commonly used PA66 and BMC. Compared with aluminum, which has a lower density, PA66 has a density of 1.14~1.17g / cm3, BMC has a density of 1.35~1.9g / cm3, and aluminum has a density of 2.7g / cm3. For the same size and shape of the housing, the weight of PA66 plastic housing can be reduced by more than half, and the weight of BMC plastic housing can be reduced by more than 30%, thereby reducing the overall weight of the motor.

[0028] Specifically, the outer shell 101 and the isolation part 102 are provided with openings for assembling the rotor 4 and the stator 6 on opposite sides. The inner side of the isolation part 102 is formed with support ribs 7 that support the outer side of the stator 6. The inherent frequency of the structure can be changed by designing the size and shape of the plastic shell 1 (adjusted by the support ribs 7 and specific shape), thereby avoiding resonance with the motor operating frequency and improving the smoothness of operation. There is an airflow gap between the inner side of the stator 6 and the isolation part 102. The roundness of the mounting surface of the stator 6 is ≤0.05mm, and the coaxiality of the support surface of the rotor 4 is ≤0.05mm, ensuring the uniformity of the air gap δ=0.3±0.04mm and ensuring the heat dissipation effect.

[0029] Specifically, a first end cover 2 is installed on the opening on one side of the isolation part 102, and a rotating output shaft 3 is provided between the isolation part 102 and the first end cover 2. The rotor 4 is installed outside the output shaft 3 and is wrapped by the isolation part 102 and the first end cover 2.

[0030] Specifically, the outer casing 101 has an opening on one side with a second end cap 5, and a groove is formed at the center of the second end cap 5 that axially fits into the end of the isolation part 102. The outer casing 101, the isolation part 102, and the second end cap 5 enclose the stator 6.

[0031] Specifically, the inner rings of the first bearing 8 and the second bearing 9 are fixed to the outside of the output shaft 3. The outer end of the first bearing 8 is fixed to the first end cover 2, and the outer ring of the second bearing 9 is fixed to the bottom of the inner side of the isolation part 102.

[0032] Specifically, rotor 4 and stator 6 are coaxial and on the same plane, ensuring electromagnetic effect while isolating them.

[0033] The working principle and usage process of this utility model are as follows: The plastic shell 1 is integrally molded by injection molding. The rotor 4 is assembled outside the output shaft 3. The output shaft 3 is assembled in the isolation part 102 and the first end cover 2 through the first bearing 8 and the second bearing 9. The stator 6 is assembled between the outer shell part 101 and the isolation part 102 through the support rib 7. The second end cover 5 is assembled at the rear end of the plastic shell 1. At this time, the rotor 4 and the stator 6 are completely isolated and assembled into a motor.

[0034] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A plastic-cased motor structure, comprising a rotor (4) and a stator (6), characterized in that: The device includes an integrally injection-molded plastic shell (1) with a radial cross-section in the shape of a "W". The plastic shell (1) includes an outer shell portion (101) and an isolation portion (102) that completely isolate the rotor (4) and the stator (6). The outer shell portion (101) and the isolation portion (102) have openings on opposite sides for assembling the rotor (4) and the stator (6). The inner side of the isolation portion (102) has a support rib (7) that supports the outer side of the stator (6). There is an airflow gap between the inner side of the stator (6) and the isolation portion (102).

2. The plastic-cased motor structure according to claim 1, characterized in that: The opening on one side of the isolation part (102) is fitted with a first end cap (2), and a rotating output shaft (3) is provided between the isolation part (102) and the first end cap (2). The rotor (4) is installed outside the output shaft (3) and is wrapped by the isolation part (102) and the first end cap (2).

3. The plastic-cased motor structure according to claim 1, characterized in that: The outer shell (101) has an opening on one side with a second end cap (5), and a groove is formed at the center of the second end cap (5) that axially fits into the end of the isolation part (102). The outer shell (101), the isolation part (102), and the second end cap (5) enclose the stator (6).

4. The plastic-cased motor structure according to claim 2, characterized in that: The output shaft (3) is externally fixed with the inner rings of the first bearing (8) and the second bearing (9). The outer end of the first bearing (8) is fixed to the first end cover (2), and the outer ring of the second bearing (9) is fixed to the bottom of the inner side of the isolation part (102).

5. The plastic-cased motor structure according to claim 1, characterized in that: The rotor (4) and stator (6) are coaxial and in the same plane.

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