Motor rotor lightweight design and manufacturing process

Abstract

The invention discloses a motor rotor lightweight design and manufacturing process, the motor rotor lightweight design and manufacturing process comprises a permanent magnet, a rotor core, a rotating shaft bearing and a rotor winding, the rotating shaft bearing passes through the center position of the rotor core, the rotor core is provided with a permanent magnet preformed hole, the rotor winding is wound in a consequent pole winding mode, and the permanent magnet preformed hole is communicated with the permanent magnet preformed hole. The rotor iron core is formed by stacking double-layer composite soft magnetic sheets. The lightweight design and manufacturing process of the motor rotor comprises the following steps: step (a), preparing the rotor iron core; (b) a rotating shaft bearing penetrates through the center position of the rotor iron core, and permanent magnets are evenly inserted into permanent magnet reserved holes of the rotor iron core; and (c) winding, welding and packaging to obtain the motor rotor. The soft magnetic alloy layer with higher magnetic conductivity is compounded on the surface of the silicon steel sheet, so that iron loss is compensated, meanwhile, the magnetic flux density is improved, and the use of silicon steel can be greatly reduced under the same performance and cost; and the performance is higher under the same quality condition.

Description

Technical Field

[0001] The present invention relates to the field of motors, and in particular to a lightweight design and manufacturing process for motor rotors. Background Art

[0002] As an indispensable and important equipment in modern industry, the performance of motors directly affects the operating efficiency and stability of the entire system. With the continuous advancement of science and technology, the requirements for motor performance are getting higher and higher, and the market has put forward demands for motors with advantages such as light weight, low energy consumption and high efficiency.

[0003] There are two main approaches to lightweighting motor rotors. The first is to reduce the weight of the motor rotor under the premise of the same performance, and the other is to improve the performance of the motor under the premise of the same weight. Therefore, lightweighting methods can be structural optimization. There are many structural optimization technologies at present, especially the optimization of the opening position of silicon steel sheets; it can be material optimization, such as changing the wire from copper wire to aluminum wire; it can also be performance improvement, such as the position distribution of permanent magnets and the winding method of wires.

[0004] At present, silicon steel sheets have the best cost-effectiveness as soft magnetic cores. No matter how the opening amount is optimized, there is a limit. Although the use of other alloy soft magnetics may reduce weight and ensure performance requirements, it will increase production costs. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a lightweight design and manufacturing process for a motor rotor, which has the characteristics of low cost and light weight, and can meet the motor performance requirements.

[0006] To achieve the above object, the technical solution of the present invention is: The lightweight design and manufacturing process of a motor rotor includes a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack. The lightweight design and manufacturing process of the motor rotor includes the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0007] The thinner the rotor silicon steel sheet, the smaller the magnetic resistance, the greater the magnetic flux density, the smaller the magnetic loss, and the higher the efficiency of the motor, but it will lead to a decrease in its magnetic permeability and an increase in iron loss, which will have an adverse effect on the operation of the motor. The design of the lightweight rotor of the present invention compensates for the iron loss and improves the magnetic flux density by compounding a soft magnetic alloy layer with higher magnetic permeability on the surface of the silicon steel sheet.

[0008] The rotor core is prepared by the following steps: Step (1) pretreatment of silicon steel sheets: cutting the silicon steel sheets to obtain round silicon steel sheets, cleaning the surfaces, and polishing the surfaces to obtain pretreated silicon steel sheets A; Step (2) preparing molten metal: removing oil from the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, and melting them by electric arc under the protection of inert gas to obtain molten metal; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field to evenly spread the molten metal into an alloy thin layer B, cooling and sealing to obtain a double-layer composite soft magnetic sheet; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, stacking and fixing them after punching to obtain the rotor core.

[0009] In order to obtain a more uniform alloy thin layer B, the silicon steel sheet is cut into a circle, and the alloy thin layer B is obtained by rotating and scraping coating. The alloy thin layer B has higher magnetic properties than the silicon steel sheet. At the same time, the alloy thin layer B is cooled and sealed in a protective gas environment to prevent the alloy thin layer B from oxidation, ensure magnetic properties, and also ensure high resistance and reduce eddy current effects.

[0010] Preferably, in step (1), the surface roughness of the pretreated silicon steel sheet after polishing is 0.2≤Ra≤1.0μm.

[0011] In order to enable the alloy thin layer B to better adhere to the silicon steel sheet, the present invention roughens the surface of the silicon steel sheet. If Ra is less than 0.2 μm, due to the existence of surface tension of the alloy liquid during the coating process, the alloy thin layer B cannot fit the pretreated silicon steel sheet A well at the microscopic level; if Ra is greater than 1.0 μm, it will affect the magnetic properties, resulting in poor overall effect.

[0012] Preferably, in step (2), the molar ratio of Fe, Cu, Ni and Co is 0.3-0.6:0.02-0.2:0.1-0.2:0.12-0.3.

[0013] Preferably, in step (2), the surface degreasing treatment is cleaning with an alkaline solution having a pH of 8.5-11. The alkaline solution is sodium carbonate, potassium carbonate, sodium bicarbonate or sodium hydroxide solution.

[0014] Preferably, after the surface degreasing treatment in step (2), 0.01%-0.2% by weight of calcium carbonate powder, 0.3%-0.5% by weight of silicon dioxide powder and 0.01%-0.1% by weight of borate powder are added to the metal particles, and the inert gas is argon.

[0015] Calcium carbonate powder has three main functions: 1. Due to the low decomposition temperature of calcium carbonate powder, the decomposition product calcium oxide and the silicon dioxide added later can be dispersed in the alloy solution to form impurities and increase resistance; 2. It can control the grain size, prevent the grains from being too large, and ensure the magnetic properties; 3. Increase the affinity between the alloy thin layer B and the pretreated silicon steel sheet A, and increase the composite strength.

[0016] Borates have two main functions: 1. Lowering the melting point of metals; 2. Controlling grain size to ensure magnetic properties.

[0017] Preferably, in step (2), the rotation speed of the rotating disk is 5-20 r / min; and the magnitude of the magnetic field is 4000-8000 Gs.

[0018] The present invention mainly coats the molten metal on the pretreated silicon steel sheet A by means of a fixed scraper above a rotating disk, and the coating process is realized by the rotation of the rotating disk; the magnetic field has three main functions: 1. fixing the pretreated silicon steel sheet A; 2. making the molten metal have the same magnetic field orientation as the pretreated silicon steel sheet A after solidification, that is, controlling the grain orientation; 3. improving the bonding strength of the alloy thin layer B.

[0019] Preferably, in step (3), the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01-0.1.

[0020] In this solution, the magnetic permeability of the alloy thin layer B is about 5-10 times that of the pre-treated silicon steel sheet A, and the magnetic flux density is improved at the same time. Under the same performance and cost, the use of silicon steel can be greatly reduced; it has higher performance under the same quality conditions.

[0021] Preferably, in step (3), the cooling includes cooling to below 100° C. in an inert gas atmosphere, wherein the inert gas is argon; and the sealing includes coating an insulating coating on the surface of the alloy thin layer B, wherein the insulating coating includes one or more of polyimide, phosphate coating, aluminum phosphate-based coating, polyamide or polyurethane.

[0022] Preferably, in step (4), during the stacking process of the double-layer composite soft magnetic sheets, each double-layer composite soft magnetic sheet is arranged in the same spatial order.

[0023] The control of grain growth is taken into consideration during the preparation of the double-layer composite soft magnetic sheet, especially the solidification of the alloy thin layer B in the magnetic field, so that the performance of each double-layer composite soft magnetic sheet is highly consistent, so the same spatial arrangement can achieve better comprehensive performance. The same spatial order arrangement in this scheme design means that the pre-treated silicon steel sheet A and the alloy thin layer B in the double-layer composite soft magnetic sheet are arranged in the manner of ...ABABABABA... (A is the pre-treated silicon steel sheet A, B is the alloy thin layer B), so that the best comprehensive performance can be achieved, while the manner of ...ABBAABBA... or ...ABBAAABBABAAAB... etc. not only requires the exposed surface of the pre-treated silicon steel sheet A to be insulated, but also affects the comprehensive performance.

[0024] Compared with the prior art, the present invention achieves the following beneficial effects: 1. By compounding a soft magnetic alloy layer with higher magnetic permeability on the surface of silicon steel sheet, the iron loss is compensated and the magnetic flux density is improved. Under the same performance and cost, the use of silicon steel can be greatly reduced; it has higher performance under the same quality conditions; 2. The alloy thin layer B has good bonding strength with the pretreated silicon steel sheet A, the magnetic grains have good consistency of magnetic field orientation, and have good comprehensive performance. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0026] Embodiment 1: A lightweight design and manufacturing process for a motor rotor, comprising a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack, wherein the lightweight design and manufacturing process for a motor rotor comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0027] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 0.5 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 10 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 5000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.05:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0028] Embodiment 2: A lightweight design and manufacturing process for a motor rotor, comprising a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack, wherein the lightweight design and manufacturing process for a motor rotor comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0029] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 0.5 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, the rotating disk speed is 10r / min, and coating the molten metal liquid on the surface of the pretreated silicon steel sheet A in a magnetic field of 4000Gs, so that the molten metal liquid is evenly spread into an alloy thin layer B, cooling to below 100°C in an argon atmosphere, and sealing with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0030] Embodiment 3: A lightweight design and manufacturing process for a motor rotor, comprising a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack, wherein the lightweight design and manufacturing process for a motor rotor comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0031] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 0.5 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 10 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 8000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.1:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0032] Embodiment 4: A lightweight design and manufacturing process for a motor rotor, comprising a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack, wherein the lightweight design and manufacturing process for a motor rotor comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0033] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 0.5 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 20 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 4000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0034] Embodiment 5: A lightweight design and manufacturing process for a motor rotor, comprising a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, and the rotor core is a double-layer composite soft magnetic sheet stack, wherein the lightweight design and manufacturing process for a motor rotor comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0035] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 1.0 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 5 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 4000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0036] Comparative Example 1: The difference from Example 1 is that the rotor core is a stack of conventional silicon steel sheets.

[0037] Comparative Example 2: The lightweight design and manufacturing process of a motor rotor includes a permanent magnet, a rotor core, a shaft bearing and a rotor winding. The shaft bearing passes through the center of the rotor core. The rotor core is provided with a permanent magnet reserved hole. The rotor winding is wound in a stub winding manner. The rotor core is a double-layer composite soft magnetic sheet stack. The lightweight design and manufacturing process of the motor rotor includes the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0038] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 1.0 μm; Step (2) preparing molten metal: removing oil from the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, and melting them by arc under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 5 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 4000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0039] Comparative Example 3: The lightweight design and manufacturing process of a motor rotor includes a permanent magnet, a rotor core, a shaft bearing and a rotor winding. The shaft bearing passes through the center of the rotor core. The rotor core is provided with a permanent magnet reserved hole. The rotor winding is wound in a stub winding manner. The rotor core is a double-layer composite soft magnetic sheet stack. The lightweight design and manufacturing process of the motor rotor includes the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0040] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 1.0 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, the rotating disk speed is 5 r / min, applying molten metal liquid on the surface of the pretreated silicon steel sheet A, so that the molten metal liquid is evenly spread into an alloy thin layer B, cooling to below 100° C. in an argon atmosphere, and sealing with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0041] Comparative Example 4: The lightweight design and manufacturing process of a motor rotor includes a permanent magnet, a rotor core, a shaft bearing and a rotor winding. The shaft bearing passes through the center of the rotor core. The rotor core is provided with a permanent magnet reserved hole. The rotor winding is wound in a stub winding manner. The rotor core is a double-layer composite soft magnetic sheet stack. The lightweight design and manufacturing process of the motor rotor includes the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0042] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 1.5 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet at a speed of 5 r / min, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field of 1000 Gs, so that the molten metal is evenly spread into an alloy thin layer B, cooling the pretreated silicon steel sheet to below 100° C. in an argon atmosphere, and sealing the pretreated silicon steel sheet with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0043] Comparative Example 5: The lightweight design and manufacturing process of a motor rotor includes a permanent magnet, a rotor core, a shaft bearing and a rotor winding. The shaft bearing passes through the center of the rotor core. The rotor core is provided with a permanent magnet reserved hole. The rotor winding is wound in a stub winding manner. The rotor core is a double-layer composite soft magnetic sheet stack. The lightweight design and manufacturing process of the motor rotor includes the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain the motor rotor.

[0044] The rotor core is manufactured by the following steps: Step (1) pretreatment of silicon steel sheet: cutting silicon steel sheet with a thickness of 0.3 mm to obtain round silicon steel sheet, cleaning the surface with an alkaline solution with a pH of 8.5, and polishing the surface to obtain a pretreated silicon steel sheet A with a surface roughness of Ra = 1.0 μm; Step (2) preparing molten metal: degreasing the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, adding 0.1% by total weight of calcium carbonate powder, 0.4% by total weight of silicon dioxide powder and 0.05% by total weight of borate powder to the metal particles, and arc melting under argon protection to obtain molten metal, wherein the molar ratio of Fe, Cu, Ni and Co is 0.6:0.1:0.15:0.15; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, the rotating disk speed is 5 r / min, molten metal liquid is coated on the surface of the pretreated silicon steel sheet A in a magnetic field of 4000 Gs, so that the molten metal liquid is evenly spread into an alloy thin layer B, cooling to below 100° C. in an argon atmosphere, and sealing with polyimide to obtain a double-layer composite soft magnetic sheet, wherein the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.005:1; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, after punching, each double-layer composite soft magnetic sheet is arranged and stacked in the same spatial order, and fixed to obtain the rotor core.

[0045] Under the same conditions, the rotor performance is closely related to the magnetic properties of the core. Table 1 shows the magnetic properties of the single double-layer composite soft magnetic sheet and the conventional silicon steel sheet in the embodiment and the comparative example. The magnetic field strength of the magnetic flux density test is 2T; the iron loss refers to the iron loss value per unit mass of the silicon steel sheet, and the test conditions are 50 Hz AC frequency and 1.7T magnetic field strength.

[0046]

[0047] As can be seen from the above table, the double-layer composite soft magnetic sheets in Examples 1-5 have a higher magnetic flux density, up to 1.9 T, which is much higher than Comparative Examples 1-5. High magnetic flux density means that under the same conditions, these soft magnetic sheets can carry more magnetic flux, thereby improving the output efficiency and power density of the motor. In the comparative examples, especially Comparative Example 2, the magnetic flux density is significantly lower, only 0.8 T, which may be due to the presence of cracks on its surface, which affects the penetration of the magnetic field and the improvement of the magnetic flux density.

[0048] The inspection of surface cracks is mainly focused on the surface of the alloy thin layer B. The double-layer composite soft magnetic sheets in Examples 1-5 have no obvious cracks, which ensures the continuity and stability of the magnetic field. Comparative Examples 1-4 all have certain cracks on the surface, which directly leads to a significant decrease in their magnetic properties.

[0049] The double-layer composite soft magnetic sheets in Examples 1-5 show lower iron loss values, especially Examples 1, 3 and 5, whose iron loss values ​​are all lower than 1.2 W / kg. Low iron loss means that during the operation of the motor, the energy loss caused by the heating of the iron core is less, which is beneficial to improve the overall efficiency and stability of the motor. The iron loss values ​​of Comparative Examples 1-4 are generally higher, especially Comparative Examples 2 and 3, whose iron loss values ​​reach 1.70 W / kg and 1.35 W / kg respectively.

[0050] Although Comparative Example 5 has a better effect than Comparative Example 1, it has no outstanding advantages in performance and cannot reduce weight.

[0051] It can be seen from the above data that embodiments 1-5 have outstanding magnetic properties compared to comparative example 1, while the density is not much different, which means that for rotors of the same weight, embodiments 1-5 have better performance advantages; under the same performance conditions, embodiments 1-5 also have a smaller weight, achieving the goal of lightweight motor rotors.

[0052] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. The lightweight design and manufacturing process of the motor rotor is characterized by: The invention comprises a permanent magnet, a rotor core, a shaft bearing and a rotor winding, wherein the shaft bearing passes through the center of the rotor core, the rotor core is provided with a permanent magnet reserved hole, the rotor winding is wound in a stub winding manner, the rotor core is a double-layer composite soft magnetic sheet stack, and the motor rotor lightweight design and manufacturing process comprises the following steps: Step (a) preparing a rotor core; Step (b) passing the shaft bearing through the center of the rotor core, and evenly inserting the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) winding, welding and packaging to obtain a motor rotor; The rotor core is prepared by the following steps: Step (1) pretreatment of silicon steel sheets: cutting the silicon steel sheets to obtain round silicon steel sheets, cleaning the surfaces, and polishing the surfaces to obtain pretreated silicon steel sheets A; Step (2) preparing molten metal: removing oil from the surface of Fe, Cu, Ni and Co metal particles with a purity higher than 99.99%, and melting them by electric arc under the protection of inert gas to obtain molten metal; Step (3) preparing a double-layer composite soft magnetic sheet: placing a pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, coating the surface of the pretreated silicon steel sheet A with molten metal in a magnetic field to evenly spread the molten metal into an alloy thin layer B, cooling and sealing to obtain a double-layer composite soft magnetic sheet; Step (4) preparing the rotor core: punching the double-layer composite soft magnetic sheets according to the design, stacking and fixing them after punching to obtain the rotor core.

2. The lightweight design and manufacturing process of a motor rotor as claimed in claim 1, characterized in that: In step (1), the surface roughness of the pretreated silicon steel sheet after polishing is 0.2≤Ra≤1.0μm.

3. The lightweight design and manufacturing process of a motor rotor as claimed in claim 1, characterized in that: In step (2), the molar ratio of Fe, Cu, Ni and Co is 0.3-0.6:0.02-0.2:0.1-0.2:0.12-0.

3.

4. The motor rotor lightweight design and manufacturing process according to claim 1, characterized in that: In step (2), the surface degreasing treatment is performed by washing with an alkaline solution having a pH value of 8.5-11.

5. The motor rotor lightweight design and manufacturing process according to claim 1, characterized in that: In step (2), after the surface is degreased, 0.01%-0.2% of calcium carbonate powder, 0.3%-0.5% of silicon dioxide powder and 0.01%-0.1% of borate powder are added to the metal particles, and the inert gas is argon.

6. The lightweight design and manufacturing process of a motor rotor according to claim 1, characterized in that: In step (2), the rotation speed of the rotating disk is 5-20 r / min; the magnitude of the magnetic field is 4000-8000 Gs.

7. The motor rotor lightweight design and manufacturing process according to claim 1, characterized in that: In step (3), the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01-0.

1.

8. The motor rotor lightweight design and manufacturing process according to claim 1, characterized in that: In step (3), the cooling includes cooling to below 100° C. in an inert gas atmosphere, wherein the inert gas is argon; the sealing includes coating an insulating coating on the surface of the alloy thin layer B, wherein the insulating coating includes one or more of polyimide, phosphate coating, aluminum phosphate-based coating, polyamide or polyurethane.

9. The motor rotor lightweight design and manufacturing process according to claim 1, characterized in that: In step (4), during the stacking process of the double-layer composite soft magnetic sheets, each double-layer composite soft magnetic sheet is arranged in the same spatial order.

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