Lightweight Design and Manufacturing Process of Motor Rotor

Abstract

The present invention discloses a lightweight design and manufacturing process for a motor rotor, which 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 permanent magnet reserved holes. The rotor winding is wound in a fractional-pitch winding manner. The rotor core is stacked by double-layer composite soft magnetic sheets. The lightweight design and manufacturing process for the motor rotor includes the following steps: Step (a) Prepare the rotor core; Step (b) Pass the shaft bearing through the center of the rotor core, and evenly insert the permanent magnets into the permanent magnet reserved holes of the rotor core; Step (c) Wind the wire, weld, and encapsulate to obtain the motor rotor. By compounding a soft magnetic alloy layer with a higher magnetic permeability on the surface of the silicon steel sheet, the present invention compensates for the iron loss and improves the magnetic flux density at the same time. Under the same performance and cost conditions, the use of silicon steel can be greatly reduced; it has higher performance under the same mass condition.

Description

Technical Field

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

[0002] As an indispensable important device in modern industry, the performance of a motor directly affects the operating efficiency and stability of the entire system. With the continuous progress of 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 ideas for the lightweight of motor rotors. The first is to reduce the weight of the motor rotor under the premise of the same performance, and the second is to improve the performance of the motor under the premise of the same weight. Therefore, the lightweight method can be structural optimization. There are many current technologies for structural optimization, especially the optimization of the punching positions of silicon steel sheets; it can be material optimization, such as changing the wire from copper wire to aluminum wire; it can also be the improvement of performance, such as the position distribution of permanent magnets and the winding method of wires, etc.

[0004] At present, silicon steel sheets, as soft magnetic cores, have the best cost performance. No matter how the punching amount is optimized, there is ultimately a limit. While using other alloy soft magnets may reduce the weight and meet the performance requirements, it will increase the production cost. Summary of the Invention

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

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A lightweight design and manufacturing process for a motor rotor, including a permanent magnet, a rotor core, a shaft bearing, and a rotor winding. The shaft bearing passes through the central position of the rotor core. The rotor core is provided with permanent magnet reserved holes. The rotor winding is wound in a fractional-pitch winding manner. The rotor core is stacked by double-layer composite soft magnetic sheets. The lightweight design and manufacturing process for the motor rotor includes the following steps:

[0008] Step (a) Prepare the rotor core;

[0009] Step (b) Pass the shaft bearing through the central position of the rotor core, and evenly insert the permanent magnets into the permanent magnet reserved holes of the rotor core;

[0010] Step (c) Wind the wire, weld, and encapsulate to obtain the motor rotor.

[0011] The thinner the rotor silicon steel sheet, the smaller the magnetic resistance, the larger the magnetic flux density, the smaller the magnetic loss, and the higher the efficiency of the motor. However, this will lead to a decrease in its magnetic permeability and an increase in iron loss, which has 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 increases the magnetic flux density by compositing a soft magnetic alloy layer with a higher magnetic permeability on the surface of the silicon steel sheet.

[0012] The rotor core is prepared through the following steps:

[0013] Step (1) Pretreatment of silicon steel sheet: Cut the silicon steel sheet to obtain a circular silicon steel sheet, clean the surface, and simultaneously polish the surface to obtain the pretreated silicon steel sheet A;

[0014] Step (2) Preparation of molten metal liquid: Degrease the surfaces of Fe, Cu, Ni, and Co metal particles with a purity higher than 99.99%, and use arc melting under the protection of an inert gas to obtain the molten metal liquid;

[0015] Step (3) Preparation of double-layer composite soft magnetic sheet: Place the pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet, coat the molten metal liquid on the surface of the pretreated silicon steel sheet A in a magnetic field, and spread the molten metal liquid evenly to form an alloy thin layer B, and cool and seal-coat to obtain the double-layer composite soft magnetic sheet;

[0016] Step (4) Preparation of rotor core: Stamp the double-layer composite soft magnetic sheet according to the design, stack and fix after stamping to obtain the rotor core.

[0017] In order to obtain a more uniform alloy thin layer B, the silicon steel sheet is cut into a circular shape, and the alloy thin layer B is obtained by means of rotation and squeegee coating. The alloy thin layer B has higher magnetic properties than the silicon steel sheet. At the same time, cooling and seal-coating the alloy thin layer B in a protective gas environment can prevent the alloy thin layer B from being oxidized, ensure the magnetic properties, and also ensure high resistance and reduce the eddy current effect.

[0018] Preferably, in step (1), the surface roughness of the pretreated silicon steel sheet after polishing satisfies 0.2 ≤ Ra ≤ 1.0 μm.

[0019] In order to enable the alloy thin layer B to better adhere to the silicon steel sheet, the surface of the silicon steel sheet is roughened in the present invention. If Ra < 0.2 μm, due to the existence of the surface tension of the alloy liquid during the coating process, the alloy thin layer B cannot fit well with the pretreated silicon steel sheet A at the microscopic level; if Ra > 1.0 μm, it will affect the magnetic properties and result in poor comprehensive effects.

[0020] Preferably, in step (2), Fe, Cu, Ni, and Co satisfy a molar ratio of 0.3 - 0.6:0.02 - 0.2:0.1 - 0.2:0.12 - 0.3.

[0021] Preferably, in step (2), the surface degreasing treatment is to clean 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.

[0022] Preferably, after the surface degreasing treatment in step (2), calcium carbonate powder with a total mass of 0.01% - 0.2%, silicon dioxide powder of 0.3% - 0.5% and borate powder of 0.01% - 0.1% are added to the metal particles. The inert gas is argon.

[0023] Calcium carbonate powder mainly has three functions: 1. Since the decomposition temperature of calcium carbonate powder is low, the decomposition products calcium oxide and the later added silicon dioxide can be dispersed in the alloy solution to form impurities and increase the resistance; 2. It can control the grain size, prevent the grains from being too large and ensure the magnetic properties; 3. It increases the affinity between the alloy thin layer B and the pretreated silicon steel sheet A and increases the composite strength.

[0024] Borate mainly has two functions: 1. Lower the melting point of the metal; 2. Control the grain size and ensure the magnetic properties.

[0025] Preferably, in step (2), the rotational speed of the rotating disk is 5 - 20 r / min; the magnetic field strength is 4000 - 8000 Gs.

[0026] In the present invention, the molten metal is mainly coated on the pretreated silicon steel sheet A by a fixed scraper above the rotating disk, and the coating process is realized by the rotation of the rotating disk; the magnetic field mainly has three functions: 1. Fix the pretreated silicon steel sheet A; 2. Make the molten metal have the same magnetic field orientation as the pretreated silicon steel sheet A after solidification, that is, control the grain orientation; 3. Improve the bonding strength of the alloy thin layer B.

[0027] 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.

[0028] In this solution, the magnetic permeability of the alloy thin layer B is about 5 - 10 times that of the pretreated silicon steel sheet A, and at the same time, the magnetic flux density is increased. Under the same performance and cost, the use of silicon steel can be greatly reduced; it has higher performance under the same mass condition.

[0029] Preferably, in step (3), the cooling includes cooling to below 100°C in an inert gas atmosphere, and the inert gas is argon; the sealing coating includes coating an insulating coating on the surface of the alloy thin layer B, and the coating of the insulating coating includes one or more of polyimide, phosphate paint, aluminum phosphate-based paint, polyamide or polyurethane.

[0030] 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.

[0031] 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.

[0032] Compared with the prior art, the present invention achieves the following beneficial effects:

[0033] 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;

[0034] 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

[0035] 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.

[0036] 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:

[0037] Step (a) preparing a rotor core;

[0038] 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;

[0039] Step (c) winding, welding and packaging to obtain the motor rotor.

[0040] The rotor core is manufactured by the following steps:

[0041] 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;

[0042] 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;

[0043] 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;

[0044] 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] 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:

[0046] Step (a) preparing a rotor core;

[0047] 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;

[0048] Step (c) winding, welding and packaging to obtain the motor rotor.

[0049] The rotor core is manufactured by the following steps:

[0050] 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;

[0051] 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;

[0052] 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;

[0053] 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.

[0054] 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:

[0055] Step (a) preparing a rotor core;

[0056] 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;

[0057] Step (c) winding, welding and packaging to obtain the motor rotor.

[0058] The rotor core is manufactured by the following steps:

[0059] 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;

[0060] 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;

[0061] 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;

[0062] 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.

[0063] 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:

[0064] Step (a) preparing a rotor core;

[0065] 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;

[0066] Step (c) winding, welding and packaging to obtain the motor rotor.

[0067] The rotor core is manufactured by the following steps:

[0068] 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;

[0069] 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;

[0070] 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;

[0071] 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.

[0072] 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:

[0073] Step (a) preparing a rotor core;

[0074] 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;

[0075] Step (c) winding, welding and packaging to obtain the motor rotor.

[0076] The rotor core is manufactured by the following steps:

[0077] 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;

[0078] 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;

[0079] 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;

[0080] 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.

[0081] Comparative Example 1:

[0082] The difference from Example 1 is that the rotor core is a stack of conventional silicon steel sheets.

[0083] Comparative Example 2:

[0084] 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:

[0085] Step (a) preparing a rotor core;

[0086] 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;

[0087] Step (c) winding, welding and packaging to obtain the motor rotor.

[0088] The rotor core is manufactured by the following steps:

[0089] 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;

[0090] 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;

[0091] 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;

[0092] 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.

[0093] Comparative Example 3:

[0094] 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:

[0095] Step (a) preparing a rotor core;

[0096] 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;

[0097] Step (c) winding, welding and packaging to obtain the motor rotor.

[0098] The rotor core is manufactured by the following steps:

[0099] 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;

[0100] 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;

[0101] 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;

[0102] 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.

[0103] Comparative Example 4:

[0104] 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:

[0105] Step (a) preparing a rotor core;

[0106] 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;

[0107] Step (c) winding, welding and packaging to obtain the motor rotor.

[0108] The rotor core is manufactured by the following steps:

[0109] 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;

[0110] 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;

[0111] 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;

[0112] 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.

[0113] Comparative Example 5:

[0114] 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:

[0115] Step (a) preparing a rotor core;

[0116] 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;

[0117] Step (c) winding, welding and packaging to obtain the motor rotor.

[0118] The rotor core is manufactured by the following steps:

[0119] 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;

[0120] Step (2) Preparation of molten metal: Degrease the surfaces of Fe, Cu, Ni, and Co metal particles with a purity higher than 99.99%. Add 0.1% by total mass of calcium carbonate powder, 0.4% of silicon dioxide powder, and 0.05% of borate powder to the metal particles. Under argon protection, use arc melting to obtain molten metal. The molar ratio of Fe, Cu, Ni, and Co is 0.6:0.1:0.15:0.15;

[0121] Step (3) Preparation of double-layer composite soft magnetic sheet: Place the pretreated silicon steel sheet A on a rotating disk to rotate the pretreated silicon steel sheet. The rotation speed of the rotating disk is 5 r / min. Coat the molten metal on the surface of the pretreated silicon steel sheet A in a magnetic field of 4000 Gs, and spread the molten metal evenly to form an alloy thin layer B. Cool it to below 100 °C in an argon atmosphere, and seal it with polyimide to obtain a double-layer composite soft magnetic sheet. The thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.005:1;

[0122] Step (4) Preparation of rotor core: Stamp the double-layer composite soft magnetic sheet according to the design. After stamping, each double-layer composite soft magnetic sheet is stacked and fixed in the same spatial order to obtain a rotor core.

[0123] Under the condition that other conditions are the same, the rotor performance is closely related to the magnetic performance of the core. Table 1 shows the comparison of the magnetic performance of single-piece double-layer composite soft magnetic sheets and conventional silicon steel sheets in the examples and comparative examples. The magnetic field strength for the magnetic flux density test is 2 T; the iron loss refers to the iron loss value per unit mass of the silicon steel sheet, and the test conditions are at an AC frequency of 50 Hz and a magnetic field strength of 1.7 T.

[0124]

[0125] 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, which can reach up to 1.9 T at most, far higher than that in Comparative Examples 1-5. A 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 in Comparative Example 2, its magnetic flux density is significantly lower, only 0.8 T, which may be due to the presence of cracks on its surface, affecting the magnetic field penetration and the improvement of the magnetic flux density.

[0126] The inspection of surface cracks is mainly aimed at the surface of the alloy thin layer B. There are no obvious cracks in the double-layer composite soft magnetic sheets in Examples 1-5, which ensures the continuity and stability of the magnetic field. There are certain cracks on the surfaces of Comparative Examples 1-4, which directly leads to a significant decrease in their magnetic performance.

[0127] The double-layer composite soft magnetic sheets in Examples 1-5 exhibited low iron loss values. In particular, in Examples 1, 3, and 5, the iron loss values were all lower than 1.2 W / kg. Low iron loss means that during the operation of the motor, less energy is lost due to the heating of the iron core, which is beneficial to improving the overall efficiency and stability of the motor. The iron loss values of Comparative Examples 1-4 were generally high. In particular, in Comparative Examples 2 and 3, the iron loss values reached 1.70 W / kg and 1.35 W / kg respectively.

[0128] Although Comparative Example 5 had better effects compared to Comparative Example 1, it did not have outstanding advantages in performance and could not reduce the weight.

[0129] From the above data, it can be seen that Examples 1-5 had outstanding magnetic properties compared to Comparative Example 1, and the density difference was not significant. This indicates that for rotors of the same weight, Examples 1-5 of the present invention had better performance advantages; under the same performance conditions, Examples 1-5 of the present invention also had a smaller weight, achieving the goal of a lightweight motor rotor.

[0130] As mentioned above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, should be covered by the protection scope of the present invention.

Claims

1. A lightweight manufacturing process for an electric motor rotor, characterized in that, 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 subsequent-pole winding manner, the rotor core is a double-layer composite soft magnetic sheet stack, and the motor rotor lightweight 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; In the step (1), the surface roughness of the pretreated silicon steel sheet after polishing is 0.2≤Ra≤1.0μm; 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; the magnetic field size is 4000-8000 Gs; In the step (3), the thickness ratio of the alloy thin layer B to the pretreated silicon steel sheet A is 0.01-0.

1.

2. The lightweight manufacturing process of the motor rotor according to claim 1, wherein, 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.

3. The lightweight manufacturing process of the motor rotor as claimed in claim 1, wherein, In step (2), the surface degreasing treatment is performed by washing with an alkaline solution having a pH value of 8.5-11.

4. The lightweight manufacturing process of the motor rotor according to claim 1, characterized in that, The inert gas is argon.

5. The lightweight manufacturing process of the motor rotor according to claim 1, wherein, In step (2), the rotating disk has a rotation speed of 5-20 r / min.

6. The lightweight manufacturing process of the motor rotor according to claim 1, wherein, 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.

7. The lightweight manufacturing process of the motor rotor 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.

Images