TWI861662B - Rotor coating method - Google Patents

Abstract

A rotor coating method is applicable to coating a rotor of a motor, wherein the rotor extends along an axis, and the rotor coating method comprises: (A) unfolding a carbon fiber bundle to form a carbon fiber tape; (B) wrapping the carbon fiber tape around the axis and around the rotor with a pre-tensioning force, and the winding direction of the carbon fiber tape is at an angle with a direction perpendicular to the axis; and (C) winding several layers of the carbon fiber tape back and forth along the axis, so that the carbon fiber tape is wound to form a coating layer that covers the outer peripheral surface of the rotor. The present invention can wind more layers of carbon fiber under the condition of the same winding thickness, thereby improving the installation stability of the permanent magnet in the rotor, reducing the thickness of the magnetic isolation bridge and improving the performance of the motor.

Description

Rotor coating method

The present invention relates to a method for processing a rotor, and more particularly to a method for coating a rotor with carbon fibers.

Permanent magnet synchronous motors are smaller and more energy-efficient than other types of motors, so they are often used in electric vehicles to improve their driving capabilities.

The invention patent publication No. CN115173595A of the People's Republic of China discloses a rotor of a conventional permanent magnet synchronous motor, which comprises an iron core and a plurality of permanent magnets. The iron core comprises a plurality of mounting slots for accommodating the permanent magnets, and a plurality of magnetic isolation bridges between the mounting slots and the side surface of the iron core. Since the thickness of the magnetic isolation bridges is proportional to the magnetic leakage and thus affects the performance of the permanent magnet synchronous motor, the thickness of the magnetic isolation bridges should be reduced as much as possible during the design of the rotor to reduce the magnetic leakage. However, the thinner the magnetic isolation bridges are, the more difficult it is to resist the centrifugal force generated by the rotor when rotating at high speed, which causes the permanent magnets to separate, and may cause cracks or breaks between the magnetic isolation bridges and the rotor body, causing damage to the motor.

Therefore, how to reduce the thickness of the magnetic isolation bridges of the rotor while ensuring the structural stability of the rotor at high speed remains to be solved.

Therefore, the purpose of the present invention is to provide a rotor coating that can improve motor performance and structural stability.

Therefore, the present invention provides a rotor coating method, which is applicable to coating a rotor of a motor. The rotor extends along an axis. The rotor coating method comprises:

(A) A carbon fiber bundle is unfolded to form a carbon fiber tape.

(B) The carbon fiber tape is wound around the axis and around the rotor with a pre-tensioning force, and the winding direction of the carbon fiber tape forms an angle with a direction perpendicular to the axis.

(C) Winding several layers of the carbon fiber tape back and forth along the axis, so that the carbon fiber tape is wound to form a coating layer that covers the outer peripheral surface of the rotor.

The effect of the present invention is that by unfolding and flattening the carbon fiber bundle into the carbon fiber belt and then winding it around the rotor, more layers of carbon fiber can be wound under the same winding thickness, thereby improving the installation stability of the plurality of permanent magnets in the rotor, so that the rotor can maintain structural stability during high-speed rotation when the thickness of the magnetic isolation bridge is reduced, thereby having the advantage of improving the performance of the motor.

1 to 3 , an embodiment of a rotor coating method of the present invention is applicable to coating a rotor 9 of a motor (not shown). The rotor 9 extends along an axis L.

This embodiment comprises the following steps:

Step 11: Expand a carbon fiber bundle 21 to form a carbon fiber tape 22.

Referring to FIG. 2, FIG. 7 and FIG. 8, the existing carbon fiber bundle 21 is mostly made in a bundled manner due to process technology and cost limitations. For example, the carbon fiber bundle 21 of specifications such as 1k (referring to the carbon fiber bundle 21 containing 1000 carbon fiber filaments 211), 3k, and 12k are common. For example, the carbon fiber bundle 21 of model IM600 produced by Toho Tenax Co., Ltd. of Japan has a diameter of about 5µm for a single carbon fiber filament 211, but the diameter of the carbon fiber bundle 21 of 1k specification is greater than 100µm. If the carbon fiber bundle 21 is directly wound around the rotor 9, the thickness δ2 of the coating layer 91 of the rotor 9 after the carbon fiber bundle 21 is coated will be too high, and the gap between the rotor 9 and the stator (not shown) of the motor will be too narrow, thereby affecting the operation of the motor. Therefore, the present embodiment uses a yarn spreading method to spread and rearrange the carbon fiber filaments 211 in the carbon fiber bundle 21 to form a carbon fiber tape 22, thereby reducing the thickness δ1 of the carbon fiber tape 22, and at the same time, increasing the width W of the carbon fiber tape 22 for easy coating.

It should be noted that when the number of layers of the carbon fiber tape 22 wound around the coating layer 91 is more, the structural strength of the coating layer 91 is higher, and the coating layer 91 is more able to resist the centrifugal force of the permanent magnets 92 disposed inside the rotor 9 when rotating at high speed. In order to understand the relationship between the number of layers of carbon fiber and the structural strength, carbon fiber is stacked with different numbers of layers to make two test plates C and THC as shown in Table 1, and then a three-point bending test is performed according to the ASTM D790-10 standard, and the test results are shown in Table 2.

Table 1 Test items Test plate C Test plate THC Carbon fiber layer number 20 4 size 45 mm 45 mm

Table 2 Test items Test plate C Test plate THC Maximum load (N) 84.56 97.23 Maximum displacement(mm) 2.63 1.85 Maximum bending stress(MPa) 1234.75 729.23 Flexural modulus(GPa) 64.35 39.52

From the experimental data in Table 2, it can be seen that when the test platens C and THC have similar sizes, the test platen C can withstand a greater bending stress. It is obvious that the more carbon fiber layers there are, the higher the structural strength.

In this embodiment, the thickness δ2 of the coating layer 91 is between 100 and 1000 µm. For example, if the thickness δ2 of the coating layer 91 is 700 µm, and the carbon fiber tape 22 with a thickness δ1 of 70 µm is used for coating, the coating layer 91 can include 10 layers of the carbon fiber tape 22. In contrast, if the carbon fiber bundle 21 with a specification of 5 µm -1k is used, the coating layer 91 can only be coated with 6 layers at most, so the structural strength is poor. It is obvious that the coating layer 91 formed by the carbon fiber tape 22 has the advantages of more carbon fiber layers and higher structural strength.

The yarn spreading method can be a mechanical multi-roller yarn spreading method, a heating roller-pressing yarn spreading method, an ultrasonic vibration yarn spreading method, a sonic roller-pressing yarn spreading method, or an airflow yarn spreading method, as long as the carbon fiber bundle 21 can be spread out and made into the carbon fiber tape 22.

In this embodiment, the carbon fiber bundle 21 with a diameter between 100 and 800 μm is unfolded and made into the carbon fiber tape 22 with a width W between 0.5 and 2 cm and a thickness δ1 between 10 and 100 μm, which can be better wrapped around the rotor 9 with a length of about 8 cm.

See Figures 1, 3 and 4. Step 12: Wrap the carbon fiber tape 22 around the axis L and around the rotor 9 with a pre-tensioning force, and the winding direction of the carbon fiber tape 22 and a vertical direction M perpendicular to the axis L form an angle θ.

When the carbon fiber tape 22 is stretched with the pre-tensioning force, the structural strength of the coated layer 91 can be improved, and the centrifugal force of the permanent magnets 92 (see FIG. 7 ) inside the rotor 9 during high-speed rotation can be better resisted. As shown in Table 3, in the experiment, the carbon fiber was coated on two identical hollow circular tubes by method A and method B, respectively, and the hollow circular tubes were subjected to dynamic torsion test. The method A is a method of coating the carbon fiber tape 22 with the pre-tensioning force as in step 12 of the embodiment. The method B is a method of coating the carbon fiber cloth cut into sheets by the traditional layer winding method without maintaining the pre-tensioning force.

Table 3 Coating method Coating thickness Cycle limit Load torque (kgf-cm) Method A 2.2mm More than 200,000 times 5000 Method B 3mm About 150,000 times 4000

From the experimental data in Table 3, it can be seen that method A using step 11 can withstand higher load torque and cycle times with the same or even thinner coating thickness than method B. Since the method of dynamic torque test can be inferred by those with ordinary knowledge in the field based on the above description, no further explanation is given.

The pre-tensioning force includes a predetermined tension value and an error range, wherein the predetermined tension value is between 0.1 and 5 kg·m/s². The error range is between ± 0.1 and 5 kg·m/s². For example, when the predetermined tension value is set to 5 kg·m/s² and the error range is set to ± 0.1 kg·m/s², the pre-tensioning force is between 4.9 and 5.1 kg·m/s².

In addition, in order to ensure the uniformity of the coating thickness δ2 (see FIG. 8 ) and avoid the outer surface of the coating layer 91 being uneven, the angle θ between the winding direction of the carbon fiber tape 22 and the vertical direction M is set to be between 1° and 60°. In this embodiment, the rotor 9 is disposed on a rotating device 3 and can rotate along the axis L. At the same time, the carbon fiber tape 22 is disposed on a conveying device 4. The conveying device 4 moves the carbon fiber tape 22 relative to the rotor 9 along the extending direction of the axis L according to the rotation of the rotor 9, thereby adjusting the winding direction of the carbon fiber tape 22 and the angle θ. Since a person having ordinary knowledge in the art can infer the expanded details of the conveying device 4 for conveying strip-shaped raw materials based on the above description, no further explanation is given.

See Figure 1, Figure 4 and Figure 5. Step 13: Winding several layers of the carbon fiber tape 22 back and forth along the axis L, so that the carbon fiber tape 22 is wound to form a coating layer 91 that covers the outer peripheral surface of the rotor 9.

After the carbon fiber tape 22 is wrapped around one end of the rotor 9 in the front (toward the right in FIG. 4 ) along a front-rear direction X, it is turned through the conveying device 4 and wrapped around the other end of the rotor 9 in the rear (toward the left in FIG. 4 ), thereby winding several layers of the carbon fiber tape 22 to form the coating layer 91. The carbon fiber tape 22 can be wrapped around both ends of the rotor 9 at the angle θ with the vertical direction M, thereby maintaining the same thickness of the carbon fiber tape 22 when wrapping forward and backward.

Referring to FIG. 4 , FIG. 5 and FIG. 6 , the embodiment may further optionally include the following steps:

Step 14: Connect the carbon fiber tape 22 to a tension meter 51 . The tension meter measures a winding tension F of the carbon fiber tape 22 and outputs the measured value to a controller 52 .

The signal of the tension gauge 51 is connected to the controller 52. The tension gauge 51 can be an infrared tension gauge, an ultrasonic tension gauge, or a pen-type tension gauge, as long as it can measure the winding tension F. The controller 52 can be a central processing unit (CPU), a microcontroller (MCU), or other electronic circuit devices capable of monitoring the signal of the tension gauge 51.

Step 15: When the winding tension F deviates from the pre-tensioning tension, the controller 52 controls a tension adjuster 53 connected to the carbon fiber tape 22 to adjust the tension of the carbon fiber tape 22.

The number of the tension adjusters 53 may also be plural, for example, two, three, or more than three. The tension adjuster 53 may be implemented by a servo motor (not shown) in the conveying device 4 for conveying the carbon fiber tape 22. It is understandable that when the rotation speed of the rotating device 3 increases relative to the speed at which the servo motor conveys the carbon fiber tape 22, the winding tension F to which the carbon fiber tape 22 is subjected will increase. Therefore, as long as the winding tension F reaches the pre-tensioning tension, the controller 52 can control the tension adjuster 53 so that the speed at which the servo motor conveys the carbon fiber tape 22 is equal to the rotation speed of the rotating device 3, so that the carbon fiber tape 22 in winding maintains the pre-tensioning tension. In other variations, the tension adjuster 53 may also be other types of tension adjusters, for example, it may be implemented by a pulley set around which the carbon fiber belt 22 is movably wound, and the carbon fiber belt 22 is stretched or relaxed by displacement between the pulleys, thereby adjusting the tension of the carbon fiber belt 22.

7 and 8 , after winding, the carbon fiber tape 22 is wrapped around the outer sides of the permanent magnets 92 of the rotor 9 to form the wrapping layer 91 .

In this embodiment, the permanent magnets 92 are disposed in a plurality of grooves 930 of an iron core 93 of the rotor 9 and fixed by the coating layer 91. Since the coating layer 91 has a high structural strength, the rotor 9 can reduce the thickness of the magnetic isolation bridge or even not provide a magnetic isolation bridge, and can also fix the permanent magnets 92 during high-speed rotation without causing the permanent magnets 92 to fall off and cause damage to the motor.

Through the above description, the advantages of the above embodiments can be summarized as follows:

1. By unfolding the carbon fiber bundle 21 and flattening it into the carbon fiber belt 22 through steps 11 to 13 and then winding it around the rotor 9, more layers of carbon fibers can be wound under the same winding thickness, thereby improving the installation stability of the permanent magnets 92 in the rotor 9, so that the rotor 9 can maintain structural stability during high-speed rotation when the thickness of the magnetic isolation bridge is reduced, thereby having the advantage of improving the performance of the motor.

Second, the conveying device 4 moves the position of the carbon fiber tape 22 relative to the rotor 9 according to the rotation of the rotor 9 driven by the rotating device 3, so that the carbon fiber tape 22 maintains the angle θ when wrapping the two ends of the rotor 9 respectively, which can improve the consistency of the thickness δ2 of the coating layer 91.

3. By using the tension gauge 51, the controller 52 and the tension adjuster 53 in step 14 to maintain the pre-tension of the carbon fiber tape 22 when wrapping the rotor 9, the consistency of the wrapping can be improved, and at the same time, the structural strength of the wrapping layer 91 can be improved.

However, the above is only an example of the implementation of the present invention, and it should not be used to limit the scope of the implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

11~13: Steps 21: Carbon fiber bundle 211: Carbon fiber filament 22: Carbon fiber tape 3: Rotating device 4: Conveying device 51: Tension gauge 52: Controller 53: Tension adjuster 9: Rotor 91: Coating 92: Permanent magnet 93: Iron core 930: Groove L: Axis M: Vertical direction W: Width δ1: Thickness of carbon fiber tape δ2: Thickness of coating F: Winding tension

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a flow chart illustrating an embodiment of a rotor coating method of the present invention; FIG. 2 is a three-dimensional schematic diagram of the embodiment, illustrating a carbon fiber bundle being made into a carbon fiber tape after unwinding; FIG. 3 is a three-dimensional schematic diagram of the embodiment, illustrating the process of coating the carbon fiber tape on a rotor; FIG. 4 is a schematic diagram of FIG. 1, illustrating the carbon fiber tape being wound around the rotor at an angle; FIG. 5 is a schematic diagram similar to FIG. 4, but the carbon fiber tape is wound around the rotor in another direction; FIG. 6 is a block diagram of the embodiment; FIG. 7 is a cross-sectional schematic diagram of the embodiment, illustrating the internal structure of the rotor; and FIG8 is a schematic cross-sectional view of a portion of the embodiment, illustrating the structure of a coating layer.

11~13: Steps

Claims (9)

A rotor coating method is applicable to coating a rotor of a motor, the rotor extending along an axis, the rotor coating method comprising: (A) unfolding a carbon fiber bundle to form a carbon fiber tape; (B) wrapping the carbon fiber tape around the axis and around the rotor with a pre-tensioning force, and the winding direction of the carbon fiber tape is at an angle with a direction perpendicular to the axis; (C) winding several layers of the carbon fiber tape back and forth along the axis, so that the carbon fiber tape is The carbon fiber tape is wound to form a coating layer covering the outer circumference of the rotor; (D) the carbon fiber tape is connected to a tension gauge, the tension gauge measures a winding tension of the carbon fiber tape and outputs it to a controller; and (E) the controller controls at least one tension adjuster connected to the carbon fiber tape to adjust the tension of the carbon fiber tape when the winding tension deviates from the pre-tension, wherein the pre-tension includes a predetermined tension value and an error range. The rotor coating method as described in claim 1, wherein in step (B), the rotor is disposed on a rotating device and can rotate along the axis, and the carbon fiber belt is disposed on a conveying device, and the conveying device moves the position of the carbon fiber belt relative to the rotor according to the rotation of the rotor. The rotor coating method as described in claim 2, wherein in step (C), when the carbon fiber tape is wound back and forth along the axis, the angle between the carbon fiber tape and the vertical direction is substantially the same. The rotor coating method as described in claim 1, wherein in step (C), the carbon fiber tape is coated on the outer side of several permanent magnets of the rotor. The rotor wrapping method as described in claim 1, wherein the at least one tension adjuster has a servo motor. The rotor covering method as described in claim 1, wherein the pre-tensioning force includes a predetermined tension value and an error range, and the predetermined tension value is between 0.1 and 5 kg. m/s ² . The rotor coating method as described in claim 1, wherein the angle is between 1° and 60°. The rotor coating method as described in claim 1, wherein the diameter of the carbon fiber bundle is between 100 and 800 μm, and the width of the carbon fiber tape is between 0.5 and 2 cm, and the thickness is between 10 and 100 μm. The rotor coating method as described in claim 1, wherein the thickness of the coating layer is between 100 and 1000 μm.

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