A drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material

Abstract

This invention discloses a drive motor housing based on a negative Poisson's ratio gradient layered porous material, comprising a porous layer and a composite layer. The porous layer includes first to fourth unit layers, with porosity gradually decreasing from the inside out. The first to third unit layers are formed by an array of open-cell negative Poisson's ratio unit cells, and the fourth unit layer is formed by an array of closed-cell negative Poisson's ratio unit cells. The composite layer is formed by electrophoretically depositing graphene solution onto a closed-cell foam metal plate. The multilayer material with a negative Poisson's ratio structure used in this invention has excellent vibration reduction, noise reduction, and impact resistance properties. The gradient porous layer design effectively increases sound absorption performance, effectively reducing motor vibration noise and electromagnetic noise. The gradient porous layer structure forms excellent heat dissipation fins, which can quickly conduct the heat generated by the motor to the outside, ensuring stable motor operation. The combination of the composite layer and the porous layer has excellent performance in repeatedly absorbing electromagnetic waves.

Description

Technical Field

[0001] This invention relates to the field of drive motor devices for new energy vehicles, and in particular to a drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material. Background Technology

[0002] A drive motor is a mechanical device that converts electrical energy into mechanical energy using the law of electromagnetic induction. With the continuous development of electric vehicles, the torque and efficiency requirements of drive motors are becoming increasingly stringent. Commercial electric vehicles have very high-power drive motors, which generate a significant amount of heat. Therefore, good heat dissipation performance has become a crucial criterion for evaluating high-performance drive motors.

[0003] Existing drive motor cooling devices cannot meet the heat dissipation requirements of high-performance drive motors, limiting the power of the drive motors. At the same time, the protection is inadequate, and the suppression effect on vibration and high-order electromagnetic noise caused by the high-speed rotation of the drive motor is poor, causing serious physiological and psychological discomfort to users and affecting the service life of the drive motor.

[0004] Since drive motors rely on the law of electromagnetic induction to operate, they inevitably cause electromagnetic interference to the outside world. As the core power component of new energy vehicles, drive motors are required to have electromagnetic shielding. In the existing technology, anti-electromagnetic motors are often made by adding an anti-electromagnetic shield or anti-electromagnetic interference device around the motor. Although this can solve the problem of electromagnetic interference to drive motors, it also leads to a larger space required to install anti-electromagnetic interference motors, which does not meet the design requirements of lightweight vehicles. At the same time, the electromagnetic shield can easily cause the drive motor to be damaged due to overheating when surrounded by the servo motor. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by providing a drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material, comprising a porous layer and a composite layer;

[0008] Both the porous layer and the composite layer are hollow cylinders with openings at both ends. The porous layer is fitted over the composite layer, and the two are interference-fitted.

[0009] The porous layer comprises first to fourth unit layers from the inside out. Each of the first to fourth unit layers is a hollow cylinder with open ends. The first to third unit layers are formed by arranging open-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The first unit layer is formed by arranging closed-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The porosity of the first to fourth unit layers is arranged in a negative gradient, gradually decreasing from the inside out, and adjacent unit layers are arranged in a face-centered cubic array.

[0010] The closed-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron, which is solid inside. The center of each of its eight triangular faces has a conical blind hole pointing towards its center, and the bottom of the conical blind hole is a spherical surface that convexes outward.

[0011] The open-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron with a spherical cavity at its center, and the center of each of the eight triangular faces of the open-cell negative Poisson's ratio unit cell has a conical through hole that communicates with the spherical cavity inside.

[0012] The open-pore negative Poisson's ratio unit cell and the closed-pore negative Poisson's ratio unit cell are made of metal;

[0013] The composite layer is formed by using a closed-cell foam metal plate as the cathode for electrophoresis and depositing graphene solution onto the surface via electrophoresis.

[0014] As a further optimization of the drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material of the present invention, the open-cell negative Poisson's ratio unit cell and the closed-cell negative Poisson's ratio unit cell are made of any one of aluminum, aluminum alloy, and nickel alloy.

[0015] As a further optimization of the drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material of the present invention, the number of unit cells in the first to fourth unit layers is the same, and the thickness of the housing ranges from 20mm to 50mm.

[0016] As a further optimization of the drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material of the present invention, the porosity of the unit cell in the first to fourth unit layers ranges from 0.75 to 0.95, and the porosity difference between adjacent unit layers ranges from 0.01 to 0.1.

[0017] As a further optimization of the drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material of the present invention, the closed-cell foam metal plate is a closed-cell foam aluminum plate with a porosity of 0.7-0.95 and a thickness of 5-8 mm, and the thickness of the graphene film layer deposited on it is 0.5-1.5 mm.

[0018] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0019] 1. This invention combines the resistive sound insulation of the composite layer with the sound absorption of the porous layer to efficiently absorb high-frequency electromagnetic noise and mechanical vibration noise from drive motors. Specifically, the porous layer, composed of an array of open and closed pores with negative Poisson's ratio units and a gradient design between layers, allows for impedance matching with air by placing the innermost layer with higher porosity. This facilitates sound waves entering the designed absorption channels and undergoing multiple refractions, efficiently dissipating sound energy. The resulting coupling effectively dissipates sound waves in a fixed frequency band. Furthermore, the porous layer, composed of a negative Poisson's ratio unit array with a gradient design, creates a negative Poisson's ratio effect between layers during mechanical vibration, enhancing structural damping. The gradient design also creates dynamic stiffness between the layers, further reducing vibration noise, protecting the drive motor, extending its lifespan, and improving the user experience.

[0020] 2. This invention addresses the problem of electromagnetic radiation interference to the external environment during the operation of a drive motor. It achieves high shielding effectiveness by combining resistive shielding of a composite layer with absorbing shielding of a porous layer. Specifically, the high conductivity and dielectric constant of aluminum foam and graphene, as well as the defects and functional group residues in the graphene structure, provide high shielding effectiveness. Furthermore, by designing a negative Poisson's ratio unit cell array of porous layers and a gradient design between layers, with high porosity located in the inner layers, it is beneficial to match the impedance of electromagnetic waves, guide electromagnetic waves into the layer, and couple to form an effective interception function for electromagnetic waves in specific frequency bands, providing excellent electromagnetic shielding effect.

[0021] 3. This invention combines the thermal conductivity of the composite layer with the heat dissipation of the porous layer to effectively dissipate the heat generated by the drive motor during operation. Specifically, after the heat from the drive motor is transferred to the porous layer, the innermost layer with the larger porosity is the first to come into contact with it, and the surface has the largest contact area with the air, which can enhance the convective heat transfer effect with the air. In addition, the heat gradually decreases from the inside to the outside, and the heat is preferentially conducted through the porous layer, forming an excellent performance with self-heating effect. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the present invention;

[0023] Figure 2 This is a partial structural diagram of the interaction of the layers in this invention;

[0024] Figure 3 This is a schematic diagram of the structure of the open-cell negative Poisson's ratio unit cell in this invention;

[0025] Figure 4 This is a schematic diagram of the structure of a closed-pore negative Poisson's ratio unit cell in this invention.

[0026] In the figure, 101-first unit layer, 102-second unit layer, 103-third unit layer, 104-fourth unit layer, 201-closed-cell foam metal plate, 202-graphene film layer. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0028] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0029] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, and / or parts, these elements, components, and / or parts are not limited by these terms. These terms are merely used to distinguish elements, components, and / or parts from one another. Therefore, the first element, component, and / or part discussed below may be a second element, component, or part without departing from the teachings of this invention.

[0030] like Figure 1 , Figure 2 As shown, the present invention discloses a drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material, comprising a porous layer and a composite layer;

[0031] Both the porous layer and the composite layer are hollow cylinders with openings at both ends. The porous layer is fitted over the composite layer, and the two are interference-fitted.

[0032] The porous layer comprises first to fourth unit layers from the inside out. Each of the first to fourth unit layers is a hollow cylinder with open ends. The first to third unit layers are formed by arranging open-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The first unit layer is formed by arranging closed-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The porosity of the first to fourth unit layers is arranged in a negative gradient, gradually decreasing from the inside out, and adjacent unit layers are arranged in a face-centered cubic array.

[0033] like Figure 4 As shown, the closed-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron, which is solid inside. The center of each of its eight triangular faces is provided with a conical blind hole pointing to its center, and the bottom of the conical blind hole is a spherical surface that convexes outward.

[0034] like Figure 3 As shown, the open-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron with a spherical cavity at its center, and the centers of the eight triangular faces on the open-cell negative Poisson's ratio unit cell are provided with conical through holes that are connected to the spherical cavities inside.

[0035] The open-pore negative Poisson's ratio unit cell and the closed-pore negative Poisson's ratio unit cell are made of metal;

[0036] The composite layer is formed by using a closed-cell foam metal plate as the cathode for electrophoresis and depositing graphene solution onto the surface via electrophoresis.

[0037] The open-cell negative Poisson's ratio unit cell and the closed-cell negative Poisson's ratio unit cell are preferably made of aluminum, aluminum alloy, or nickel alloy. The number of unit cells in the first to fourth unit layers is preferably the same, and the shell thickness ranges from 20mm to 50mm. The porosity of the unit cells in the first to fourth unit layers ranges from 0.75 to 0.95, and the porosity difference between adjacent unit layers ranges from 0.01 to 0.1.

[0038] The closed-cell foam metal plate is preferably a closed-cell foam aluminum plate with a porosity of 0.7-0.95 and a thickness of 5-8 mm, and the thickness of the graphene film layer deposited on it is 0.5-1.5 mm.

[0039] The first to fourth unit layers form a metal skeleton from the inside out.

[0040] When the drive motor rotor and shaft rotate based on the law of electromagnetic induction, a strong radial electromagnetic force exists between the stator and rotor. The rotor surface drives the air to interact with the radial electromagnetic force, generating electromagnetic noise, which is particularly strong under high speed and high power load of the drive motor. The electromagnetic noise forms a sound wave with the opposite phase to the original sound wave due to the protrusions of the end cover and the reflection of the composite layer, reducing the intensity of the noise radiation. The noise that propagates through the composite layer is coupled with the mechanical vibration noise caused by rotor dynamic imbalance and road unevenness. At the same time, the frame structure responds to mechanical vibration. Due to the presence of the porous layer with negative gradient design, the innermost layer is easy to match with the air impedance, guiding the sound wave into the designed porous structure. After the sound wave enters the porous layer, it is continuously reflected and dissipated on the solid frame, ultimately achieving the purpose of sound absorption and noise reduction. The mechanical vibration responded to by the frame structure is due to the negative Poisson's ratio structure and negative gradient design. The inner layer has low stiffness and the outer layer has high stiffness, forming a mechanism similar to a spring oscillator. It can absorb the energy of mechanical vibration and dissipate it into heat, further reducing noise, protecting the motor, and extending the motor life.

[0041] The drive motor generates electromagnetic waves through the electrical energy of the rotor and the magnetic energy of the stator in the direction perpendicular to the current. When the electromagnetic waves pass through the composite layer, due to the high conductivity and high dielectric constant of aluminum foam and graphene, as well as the defects and functional group residues in the graphene structure, the electromagnetic waves are reflected multiple times in the porous structure of aluminum foam and the unique absorption and attenuation effect of graphene, which effectively reduces the intensity of electromagnetic radiation. When passing through the porous layer, the negative gradient design of the porous layer can increase the reflection space and guide the electromagnetic waves into the designed porous structure. After repeated reflection and absorption by the porous layer, most of the energy is dissipated and exists in the form of heat in the metal skeleton.

[0042] During the heat generated by the drive motor, the closed-cell aluminum foam layer effectively isolates the heat from the external environment, while the heat inside the drive motor is conducted to the graphene film layer through the aluminum foam skeleton. Graphene has a high thermal conductivity, which can quickly and evenly conduct heat to the other side surface. The porous layer with a negative gradient design is in close contact with the graphene surface, and the heat is first conducted to the porous metal skeleton. The innermost layer has a large porosity and a large surface area in contact with air, which can enhance the convective heat transfer effect with the air. Furthermore, the heat gradually decreases from the inside to the outside, and the heat is preferentially conducted to the outer skeleton through the metal skeleton. In order to enhance the heat transfer performance, the metal skeleton is enlarged, that is, the porosity is reduced to achieve the purpose, forming excellent performance with self-heating effect.

[0043] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0044] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material, characterized in that, It includes porous layers and composite layers; Both the porous layer and the composite layer are hollow cylinders with openings at both ends. The porous layer is fitted over the composite layer, and the two are interference-fitted. The porous layer comprises first to fourth unit layers from the inside out. Each of the first to fourth unit layers is a hollow cylinder with open ends. The first to third unit layers are formed by arranging open-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The first unit layer is formed by arranging closed-cell negative Poisson's ratio unit cells in a face-centered cubic array along the central axis. The porosity of the first to fourth unit layers is arranged in a negative gradient, gradually decreasing from the inside out, and adjacent unit layers are arranged in a face-centered cubic array. The closed-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron, which is solid inside. The center of each of its eight triangular faces has a conical blind hole pointing towards its center, and the bottom of the conical blind hole is a spherical surface that convexes outward. The open-cell negative Poisson's ratio unit cell is an Archimedean tetrahedron with a spherical cavity at its center, and the center of each of the eight triangular faces of the open-cell negative Poisson's ratio unit cell has a conical through hole that communicates with the spherical cavity inside. The open-pore negative Poisson's ratio unit cell and the closed-pore negative Poisson's ratio unit cell are made of metal; The composite layer is formed by using a closed-cell foam metal plate as the cathode for electrophoresis and depositing graphene solution onto the surface via electrophoresis.

2. The drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material according to claim 1, characterized in that, The open-pore negative Poisson's ratio unit cell and the closed-pore negative Poisson's ratio unit cell are made of any one of aluminum, aluminum alloy, and nickel alloy.

3. The drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material according to claim 1, characterized in that, The number of cells in the first to fourth unit layers is the same, and the shell thickness ranges from 20mm to 50mm.

4. The drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material according to claim 1, characterized in that, The porosity of a single cell in the first to fourth unit layers ranges from 0.75 to 0.95, and the porosity difference between adjacent unit layers ranges from 0.01 to 0.

1.

5. The drive motor housing based on a negative Poisson's ratio gradient hierarchical porous material according to claim 1, characterized in that, The closed-cell foam metal plate is made of closed-cell foam aluminum plate with a porosity of 0.7-0.95 and a thickness of 5-8 mm. The thickness of the graphene film layer deposited on it is 0.5-1.5 mm.

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