A plastic end cover for an excitation motor

Abstract

The utility model discloses a kind of plastic end covers for excitation motor, including plastic base, heat-conducting metal insert and magnetic shielding layer.The plastic base is annular overall structure, the center is equipped with bearing mounting seat, outer edge is equipped with mounting lug;The inner surface of plastic base is equipped with several ribbed grooves along radial direction, heat-conducting metal insert is embedded in it and is thermally connected with bearing mounting seat, and outer end is fixedly connected with heat dissipation ring, for forming the heat conduction channel from bearing area to end cover outer surface;Magnetic shielding layer is annularly distributed embedded soft magnetic fan piece structure, is set to the inner side wall or back of plastic base, for absorbing and guiding motor end leakage magnetic flux.The utility model is through the composite design of heat-conducting metal insert and magnetic shielding layer, realizes the collaborative promotion of heat dissipation and electromagnetic shielding, significantly reduces motor operating temperature rise and end leakage magnetic flux interference, improves the operating stability and service life of excitation motor.

Description

Technical Field

[0001] This utility model relates to the field of motor end cap technology, specifically a plastic end cap for an excitation motor. Background Technology

[0002] Currently, excitation motors are widely used in various industrial control equipment, generator sets, and servo drive systems. Their end cap structures not only support bearings and fix stator assemblies but also play a crucial role in heat conduction and magnetic field shielding. Traditional motor end caps typically use an integral cast aluminum alloy structure, which has some thermal conductivity, but still has significant shortcomings in insulation performance, magnetic shielding effect, and lightweight design.

[0003] In existing technologies, to improve heat dissipation performance, a common practice is to install heat dissipation fins or fan blade structures on the outside of the metal end cover to enhance natural convection heat transfer. However, the heat conduction path of such structures is still concentrated inside the metal body, and the heat transfer to the outer surface is relatively long, resulting in severe local heat accumulation. Especially when the exciter motor is running for a long time, the bearing area is prone to excessive temperature rise, which can lead to lubricant deterioration, changes in bearing clearance, or even premature failure.

[0004] On the other hand, during operation, the excitation motor generates a strong alternating magnetic field between the stator and rotor, making end magnetic leakage unavoidable. Traditional metal end caps, being made entirely of conductive material, are prone to forming eddy current loops. Under the influence of the magnetic field, this not only leads to additional heat loss but also weakens the uniformity of the magnetic field distribution. Some technical solutions attempt to use non-metallic materials (such as engineering plastics or resins) to make end caps to improve insulation and weight issues, but their poor thermal conductivity cannot effectively reduce heat accumulation inside the motor. Furthermore, non-metallic materials do not absorb leakage magnetic field, resulting in significant magnetic field leakage at the motor ends, which can easily cause electromagnetic interference to nearby sensors, control devices, or signal lines.

[0005] In view of this, we have studied and improved the existing problems and provided a plastic end cap for excitation motors to solve the current problems. The aim of this technology is to solve the problems and improve the practical value. Utility Model Content

[0006] This utility model aims to solve one of the technical problems existing in the prior art or related technologies.

[0007] Therefore, the technical solution adopted by this utility model is as follows: a plastic end cap for an excitation motor, comprising a plastic substrate, a thermally conductive metal insert, and a magnetic shielding layer. The plastic substrate is an integral annular structure with a bearing mounting seat at its center and mounting lugs evenly distributed on its outer edge to facilitate reliable fixing of the end cap to the motor housing. Several ribbed grooves are radially distributed on the inner surface of the plastic substrate, and the thermally conductive metal insert is embedded in these grooves and connected to the bearing mounting seat, forming the main heat conduction path inside the end cap. The magnetic shielding layer covers the inner wall or back of the plastic substrate, absorbing leakage magnetic flux at the motor end and guiding it to form a low magnetic reluctance circuit. The entire end cap is made of a thermally conductive and insulating composite material, thus achieving a performance balance between thermal conductivity and electrical isolation.

[0008] Specifically, through the above structural design, this utility model can achieve efficient heat conduction from the bearing mounting area to the outside of the motor, while suppressing electromagnetic interference caused by end leakage magnetic field, making the motor operation more stable and reliable.

[0009] In a preferred embodiment, the thermally conductive metal insert is further configured as follows: the thermally conductive metal insert is a flat strip-shaped component made of aluminum or copper, extending radially from the bearing mounting seat to the outer edge of the plastic substrate, and is fixedly connected to the outer peripheral heat dissipation ring to form a continuous internal heat conduction channel.

[0010] Specifically, this design allows the heat generated during motor operation to be quickly transferred to the heat dissipation ring on the outside of the end cover via the heat-conducting insert, and then exchanged with the air through the heat dissipation fins, thereby significantly improving the heat dissipation efficiency of the end cover and reducing the temperature rise of the bearing.

[0011] In a preferred embodiment, the magnetic shielding layer is further configured as follows: the magnetic shielding layer is an embedded soft magnetic fan structure, made of iron-nickel alloy, iron-silicon-aluminum alloy or ferrite material, and is arranged equidistantly along the back of the plastic substrate.

[0012] Specifically, the structure forms a complete closed magnetic flux path through several soft magnetic fan blades, which is used to absorb and guide the leakage magnetic field at the end of the excitation motor, so that the magnetic field is closed in the end circuit, thereby effectively reducing electromagnetic interference to external electronic components and improving the magnetic field stability of the motor.

[0013] In a preferred embodiment, the plastic matrix is ​​further configured as follows: the plastic matrix is ​​made of high-strength insulating plastic containing thermally conductive filler, which is flake graphite or aluminum nitride particles, to improve the overall thermal conductivity of the material and maintain high resistivity.

[0014] Specifically, the thermal conductivity of thermally conductive composite plastics can be 3 to 5 times that of ordinary nylon materials, significantly improving the heat conduction performance of the end caps while maintaining excellent insulation performance and molding stability.

[0015] In a preferred embodiment, the thermally conductive metal insert and the plastic substrate are integrated and fixed through an injection molding process. The surface of the metal insert is provided with several protrusions or through-hole structures to enhance the mechanical bonding force and thermal contact area between the insert and the plastic.

[0016] Specifically, this structure avoids the problem of interface delamination caused by differences in thermal expansion, ensuring stable thermal conductivity and a robust structure during long-term use.

[0017] In a preferred embodiment, an insulating layer is further configured between the magnetic shielding layer and the thermally conductive metal insert to prevent induced current from circulating in the metal component. The insulating layer can be implemented using injection-molded ribs or a high-temperature resistant insulating film.

[0018] Specifically, this isolation design prevents additional eddy current losses caused by changes in the magnetic field, while maintaining electrical safety between the magnetic shielding structure and the thermally conductive structure.

[0019] In a preferred embodiment, the bearing mounting base is further configured such that it is thermally connected to a thermally conductive metal insert, and the outer peripheral heat dissipation ring is provided with circumferential heat dissipation ribs, forming a main heat dissipation channel from the bearing area to the outer surface of the end cover.

[0020] Specifically, this structure can form an efficient heat dissipation path in the bearing area, effectively reducing the temperature rise of the motor bearing and extending the bearing lubrication life, making it suitable for the continuous operation requirements of medium and high power excitation motors.

[0021] The beneficial effects achieved by this utility model are as follows: 1. In this utility model, by setting a heat-conducting metal insert inside the plastic end cover and forming a continuous heat-conducting channel with the bearing mounting seat and heat dissipation ring, the heat generated during the operation of the motor can be quickly conducted from the bearing area to the outside of the end cover, which significantly improves the heat dissipation efficiency and reduces the bearing temperature rise, thereby improving the overall thermal stability and service life of the motor.

[0022] 2. In this utility model, by embedding a circumferentially distributed soft magnetic fan-shaped magnetic shielding layer on the back of the end cover, a low magnetic reluctance magnetic flux circuit is formed, which effectively absorbs and guides the leakage magnetic flux at the end of the excitation motor, reduces the impact of electromagnetic interference on surrounding components, and achieves a synergistic improvement in the lightweight structure and magnetic shielding performance of the end cover. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the present utility model; Figure 2 This is an exploded structural diagram of one embodiment of the present invention; Figure 3 This is a schematic diagram of the rear structure of one embodiment of the present invention.

[0024] Figure label: 100. Plastic substrate; 110. Bearing mount; 120. Lug; 130. Rib groove; 200, thermally conductive metal insert; 300, magnetic shielding layer. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features of the present utility model can be combined with each other.

[0026] It should be understood that these descriptions are merely exemplary and not intended to limit the scope of this invention.

[0027] The following describes, with reference to the accompanying drawings, some embodiments of the present invention, providing a plastic end cap for an excitation motor.

[0028] Combination Figures 1-3 As shown, the present invention provides a plastic end cap for an excitation motor, comprising a plastic substrate 100, a thermally conductive metal insert 200, and a magnetic shielding layer 300.

[0029] The plastic substrate 100 is an integral ring structure with a bearing mounting seat 110 at its center for mounting the motor output bearing. Several mounting lugs 120 are evenly distributed on the outer edge of the plastic substrate 100 for bolting to the end of the motor housing to achieve fixed installation of the end cover.

[0030] The inner surface of the plastic substrate 100 has a plurality of radially uniformly distributed ribbed grooves 130. Thermally conductive metal inserts 200 are embedded within these grooves 130 and are thermally connected to the bearing mounting base 110. Each thermally conductive metal insert 200 extends radially outward from its center, with its end fixedly connected to a heat dissipation ring 210 on the outer periphery of the plastic substrate 100, forming a continuous heat conduction path from the bearing mounting base 110 to the heat dissipation ring 210. This structure enables rapid conduction of heat generated inside the motor by the excitation coil and bearing area to the outside of the end cover, thereby improving the heat dissipation efficiency of the end cover and effectively reducing the bearing temperature rise.

[0031] In a preferred embodiment, the thermally conductive metal insert 200 is a flat strip-shaped component made of aluminum or copper, with several protrusions or through-holes on its surface. During injection molding, the plastic substrate 100 flows into these through-holes, thereby enhancing the mechanical bonding force and thermal contact area between the metal insert and the plastic substrate. Specifically, this structure prevents thermal fatigue delamination between the insert and the plastic layer under high-temperature operation, ensuring long-term thermal stability.

[0032] like Figure 2As shown, the magnetic shielding layer 300 is an embedded soft magnetic fan-shaped structure, composed of several soft magnetic fan-shaped plates distributed along the circumferential direction, and installed in the annular groove on the back of the plastic substrate 100. Each soft magnetic fan-shaped plate is spaced apart, forming a ring structure. The magnetic shielding layer 300 can be made of iron-nickel alloy, iron-silicon-aluminum alloy, or ferrite material, used to form a low-resistivity magnetic flux loop to absorb and guide leakage magnetic flux at the excitation motor end, thereby reducing electromagnetic interference from leakage magnetic flux to the control circuit or nearby sensing elements and improving the overall electromagnetic compatibility performance.

[0033] In a preferred embodiment, an insulating layer is provided between the magnetic shielding layer 300 and the thermally conductive metal insert 200 to prevent induced circulating currents from being generated in the thermally conductive metal insert due to changes in the magnetic field during motor operation, thereby avoiding additional heat loss. The insulating layer can be implemented using an epoxy resin layer, a polyimide film, or an injection-molded insulating rib structure.

[0034] The plastic matrix 100 is preferably made of a high-strength thermally conductive and insulating material, specifically a PA66, PPA, or PEEK composite material filled with graphite flakes or aluminum nitride powder. This material maintains good electrical insulation properties while significantly improving the overall thermal conductivity of the end cap, achieving a balance between lightweight design and high heat dissipation performance.

[0035] like Figure 3 As shown, the heat dissipation ring 210 is arranged on the outer peripheral end face of the plastic substrate 100, and its outer surface is provided with a circumferential or radial heat dissipation rib structure. The heat dissipation ring 210 is thermally connected to the thermally conductive metal insert 200 to form the main heat dissipation channel from the inside of the motor to the outer surface of the end cover, so that heat can be quickly dissipated through natural convection or air cooling, thereby improving the heat dissipation performance of the motor.

[0036] Specifically, during motor operation, the heat generated by the excitation winding is transferred to the bearing housing area through the stator core, and then quickly guided to the heat dissipation ring 210 by the heat-conducting metal insert 200, and dissipated through the heat dissipation fins and air convection. At the same time, the magnetic shielding layer 300 forms a closed magnetic flux path, effectively reducing magnetic flux leakage on the surface of the end cover and preventing magnetic field interference to external electronic components.

[0037] This invention achieves an integrated design of electrical insulation, magnetic shielding, and high heat dissipation by introducing a composite structure of a thermally conductive metal insert and an embedded magnetic shielding layer into a plastic end cap. Its manufacturing process involves pre-positioning the metal insert followed by injection molding, resulting in a compact structure, simple assembly, and good versatility and mass production feasibility.

[0038] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0039] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A plastic end cap for an excitation motor, characterized in that, include: The plastic substrate (100), the thermally conductive metal insert (200), and the magnetic shielding layer (300) are as follows: The plastic substrate (100) is an integral ring structure with a bearing mounting seat (110) at its center and mounting lugs (120) at its outer edge; The inner surface of the plastic substrate (100) is evenly distributed with several ribbed grooves (130) along the radial direction, and the thermally conductive metal insert (200) is embedded in the grooves (130) and is thermally connected to the bearing mounting seat (110); The magnetic shielding layer (300) is covered and disposed on the inner sidewall or back of the plastic substrate (100) to absorb and guide the leakage magnetic field at the motor end; The plastic substrate (100) is made of thermally conductive and insulating composite material to achieve electrical isolation and coordinated heat conduction.

2. A plastic end cap for an excitation motor according to claim 1, characterized in that, The heat-conducting metal insert (200) is a flat strip-shaped component made of aluminum or copper. It extends radially from the bearing mounting seat (110) to the outer edge of the plastic substrate (100) and is fixedly connected to a heat dissipation ring (210) located on the outer periphery of the plastic substrate (100), forming an internal heat conduction path to guide the heat generated inside the motor to the outside of the end cover to improve heat dissipation efficiency.

3. A plastic end cap for an excitation motor according to claim 1, characterized in that, The magnetic shielding layer (300) is an embedded soft magnetic fan structure, made of iron-nickel alloy, iron-silicon-aluminum alloy or ferrite material, and is arranged circumferentially along the back of the plastic substrate (100) to form a low magnetic resistance circuit and reduce the electromagnetic interference of motor leakage magnetic flux to surrounding components.

4. A plastic end cap for an excitation motor according to claim 1, characterized in that, The plastic matrix (100) is made of high-strength insulating plastic containing thermally conductive filler. The thermally conductive filler has a graphite sheet structure and is used to improve the overall thermal conductivity of the material and maintain its electrical insulation properties.

5. A plastic end cap for an excitation motor according to claim 1, characterized in that, The thermally conductive metal insert (200) and the plastic substrate (100) are connected by injection molding. The surface of the metal insert (200) is provided with protrusions or grooves to enhance the mechanical bonding force and thermal conductivity between the insert and the plastic substrate (100).

6. A plastic end cap for an excitation motor according to claim 1, characterized in that, An insulating layer is provided between the magnetic shielding layer (300) and the thermally conductive metal insert (200) to prevent electromagnetic induction current from forming a circulating current in the metal part and causing additional losses.

7. A plastic end cap for an excitation motor according to claim 1, characterized in that, The bearing mounting base (110) is thermally connected to the thermally conductive metal insert (200) to form a main heat dissipation channel from the bearing area to the outer surface of the end cover, which is used to reduce the temperature rise at the bearing when the motor is running.

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