Method for testing bonding strength of paint film on enameled wire coil

Abstract

The invention relates to the technical field of motor core manufacturing, in particular to a method for testing the bonding strength of a paint film on an enameled wire coil. The method comprises the steps of obtaining an enameled wire of a to-be-manufactured motor coil, and calculating the number of coils needing to be manufactured by the enameled wire; the enameled wire is made into a coil sample, then the coil sample is twisted, the coil sample is divided into a test coil with a twisted line segment and a coil segment, the twisted line segment is formed by twisting a plurality of strands of enameled wire segments, and the coil segment is formed by aligning and stacking a plurality of enameled wire coils; the test coil is placed in water paint to be subjected to paint dipping treatment, the test coil subjected to paint dipping treatment is taken out to be baked, then the test coil is cooled, the paint film bonding strength of the test coil is detected, if the paint film bonding strength meets the requirement, paint dipping can be conducted through the water paint, and otherwise, the test coil cannot be used.

Description

Technical Field

[0001] The invention relates to the technical field of motor core manufacturing, and in particular to a method for testing the bonding strength of a paint film on an enameled wire coil. Background Art

[0002] In the production of electric motor cells and other products, it is a common processing technology to carry out a varnishing process after the motor coil is completed. The motor coil is baked after varnishing. The purpose is to make the coil shaped and fixed so that it will not loosen during operation. At the same time, it also further improves the insulation performance of the paint film. If the coil does not have sufficient bonding strength after varnishing, the coil will become loose, which will not only deform the electromagnetic field and reduce the efficiency of the motor, but also may cause the coil to be thrown out of the operating room and cause short circuit failure during operation intervals.

[0003] Generally, motor coils are dipped in oil-based paint, which is not affected by the slipperiness of the enameled wire surface and is easier to bond the enameled wire coils. However, with the development of the times, due to environmental protection and other requirements, oil-based paint has excessive unorganized emissions after baking, resulting in the need to replace oil-based paint with water-based paint to meet environmental emission requirements.

[0004] However, in the actual production and application of water-based paint for motor cores, the following problems were found:

[0005] Because a slippery coating or a good lubricant is applied on the surface of the enameled wire, when the enameled wire is wound and embedded, the dip varnish cannot be well wetted on the surface of the paint film. The lubricant will also penetrate into the coil and cannot be completely adhered to the enameled wire, resulting in insufficient dip varnish strength and reduced adhesion between the dip varnish film and the enameled wire film. In addition, the bonding strength of different water-based paints is also different, so it is necessary to find a suitable water-based paint.

[0006] Especially when using enameled wires with a smaller diameter (0.10-0.50mm in diameter) for winding, the contact surface between the enameled wires is reduced due to the small wire diameter, and the water-based paint is not properly dipped after dipping, and the problem cannot be found in time, affecting the strength requirements of the coil. The existing technology cannot directly determine the bonding strength of the enameled wire of the motor core, resulting in problems being discovered after production, causing a large number of motor cores to be scrapped. Summary of the invention

[0007] The purpose of the present invention is to avoid the shortcomings of the prior art and provide a testing method for the bonding strength of the paint film on the enameled wire coil. The testing method can judge the bonding strength of the paint film on the enameled wire in advance, thereby judging whether the enameled wire used is suitable for water-based paint, effectively reducing the risk of coil short circuit failure in the motor core.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A test method for the bonding strength of a paint film on an enameled wire coil is provided, comprising the following steps:

[0010] Obtaining the enameled wire for making the motor coil, and calculating the number of coils required to be made of the enameled wire;

[0011] In order to accurately match the application environment, the number of coils required is calculated based on the actual motor and the characteristics of the enameled wire.

[0012] The enameled wire is made into a loop sample, and then the loop sample is twisted to separate the loop sample into a test coil having a twisted line segment and a coil segment, wherein the twisted line segment is composed of a plurality of enameled wire segments twisted together, and the coil segment is composed of a plurality of enameled wire coils aligned and stacked;

[0013] According to the number of coils obtained above, the number of coils is made into a coil sample, which is a plurality of coils wound together. Subsequently, the coil sample is partially twisted so that the coil sample produces a twisted segment and a coil segment, which can represent the actual winding method in the motor. The twisted coil is used as a test coil.

[0014] The test coil is placed in water-based paint for dipping, the dipped test coil is taken out and baked, and then the test coil is cooled, and the paint film bonding strength of the test coil is detected. If the paint film bonding strength meets the requirements, the water-based paint can be used for dipping, otherwise it cannot be used.

[0015] The obtained test coil is immersed in water-based paint for dipping treatment to simulate the motor core dipping treatment. After baking, the water-based paint can be solidified. After sufficient cooling, the adhesion strength of the paint film can be tested. When the paint film strength meets the requirements, water-based paint can be used for dipping, which can effectively reduce the risk of short-circuit failure of the coil in the motor core.

[0016] In some embodiments, the number of coils of the enameled wire to be made is calculated by the following formula:

[0017]

[0018] In the above formula,

[0019] d is the diameter of the enameled wire;

[0020] N is the number of coils.

[0021] The larger the diameter, the fewer turns are required. Different wire diameters have different requirements for bonding strength. The larger the wire diameter, the higher the bonding strength requirement.

[0022] In some embodiments, the step of twisting the loop comprises:

[0023] The loop sample is twisted several times from the middle position so that the loop sample forms an 8-shaped test coil, the middle of the test coil is the twisted line segment, and the two sides of the test coil are the coil segments.

[0024] The coil sample is made into an 8-shaped shape so that there are two coil segments, which is convenient for twisting by hand. Specifically, the coil sample is twisted 2.5 turns from the middle, and then rotated half a turn after the twisting is completed to obtain a sample of 8 bytes. Repeat the above steps to make at least 5 test coils for testing to ensure the validity and accuracy of the test data. The finished samples are numbered and recorded in the table.

[0025] In some embodiments, the coil sample is made on an intelligent high-voltage paint film continuity tester. The intelligent high-voltage paint film continuity tester is an existing instrument. Generally, every 10 meters of coil sample is equivalent to making 40 coils.

[0026] In some embodiments, the water-based paint is prepared by mixing a water-soluble insulating impregnating paint and water, and the weight ratio of the water-soluble insulating impregnating paint to water is 1:1.2-2.

[0027] The water added to the water-soluble insulating impregnating varnish will be evaporated during the subsequent baking. The water is only used to control the viscosity and adhesion of the configuration solvent, control the immersion time of the enameled wire, and ensure the effectiveness of the test.

[0028] Because water-based paint has a strong odor and is highly volatile, you must wear a gas mask and rubber gloves throughout chemical experiments to prevent direct contact with chemical liquids.

[0029] In some embodiments, the test coil is immersed in the water-based paint for 200s to 300s.

[0030] This varnishing time can ensure that the test coil can be well varnished.

[0031] In some embodiments, the test coil is baked at a temperature of 150° C. to 210° C., and the baking time is 50 min to 70 min.

[0032] The baking temperature and baking time can effectively cure the paint film without affecting the strength of the paint film.

[0033] In some embodiments, the time for cooling the test coil is 8 min to 15 min.

[0034] This time allows the paint film to cool sufficiently.

[0035] In some embodiments, the paint film bonding strength of the test coil is detected in the following manner, including: recording the weight of the test coil before dipping in paint as M1, recording the weight of the test coil after dipping in paint, baking and cooling as M2, calculating the paint film weight △M=M2-M1, and judging the paint film bonding strength according to the paint film weight, wherein the greater the paint film weight, the greater the paint film bonding strength.

[0036] By first recording the weight of the coil before immersion in paint, and then recording the weight of the coil after immersion in paint, the corresponding paint film weight can be obtained by subtracting the two. If the paint film weight is larger, it means that there is more paint film bonded to the coil, which means that the paint film bonding strength is greater.

[0037] In some embodiments, the paint film bonding strength of the test coil is also tested in the following manner, including: twisting the test coil in the opposite direction of the twisting direction when making the coil sample, observing the looseness of the test coil; if the coil is not loose, the paint film bonding strength meets the production requirements, otherwise it does not meet the requirements.

[0038] By twisting in the opposite direction, the bonding strength of the paint film can be observed. If the bonding strength of the paint film is not enough, twisting in the opposite direction will cause looseness. If the bonding strength of the paint film is sufficient, it will not be affected even if twisting in the opposite direction, and the ring sample will not become loose.

[0039] Beneficial effects of the method for testing the bonding strength of a paint film on an enameled wire coil of the present invention:

[0040] (1) The present invention provides a method for testing the bonding strength of the paint film on the enameled wire coil. Since the windings on the motor core in actual production are mainly twisted wire segments and untwisted coil segments, the present invention obtains a test coil having twisted wire segments and coil segments by twisting the enameled wire to be used as the coil. The test coil can simultaneously imitate the winding method of the enameled wire on the motor core, thereby facilitating the true reflection of the bonding strength of the paint film on the enameled wire. Subsequently, the test wire coil is placed in water-based paint for immersion treatment, so that the immersion and drying treatments can be performed quickly. Since the test coil only has a coil body, it is convenient and intuitive to detect the bonding strength between the coil and the paint film, thereby being able to quickly predict whether the enameled wire is suitable for the use of water-based paint, thereby reducing the risk of short-circuit failure of the coil in the motor core.

[0041] (2) The test method for the adhesion strength of the paint film on the enameled wire coil of the present invention can better judge whether the small diameter enameled wire is suitable for dipping in water-based paint, and through the test results, confirm which water-based paint is suitable for the enameled wire, so as to replace the oil-based paint. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic flow chart of a method for testing the bonding strength of a paint film on an enameled wire coil according to an embodiment of the present invention.

[0043] Figure 2 is a photograph of a test coil of an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0045] The terms used in the present invention are only for the purpose of describing specific implementation regulations, and are not intended to limit the present invention. The singular forms "a", "the" used in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0046] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various information in the present invention, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0047] Example 1

[0048] The test method for the bonding strength of the paint film on the enameled wire coil disclosed in this embodiment is as follows: Figure 1-2 As shown, the following steps are included:

[0049] Obtaining the enameled wire for making the motor coil, and calculating the number of coils required to be made of the enameled wire;

[0050] In order to accurately match the application environment, the number of coils required is calculated based on the actual motor and the characteristics of the enameled wire.

[0051] The enameled wire is made into a loop sample, and then the loop sample is twisted to separate the loop sample into a test coil having a twisted line segment and a coil segment, wherein the twisted line segment is composed of a plurality of enameled wire segments twisted together, and the coil segment is composed of a plurality of enameled wire coils aligned and stacked;

[0052] According to the number of coils obtained above, the number of coils is made into a coil sample, which is a plurality of coils wound together. Subsequently, the coil sample is partially twisted so that the coil sample produces a twisted segment and a coil segment, which can represent the actual winding method in the motor. The twisted coil is used as a test coil.

[0053] The test coil is placed in water-based paint for dipping, the dipped test coil is taken out and baked, and then the test coil is cooled, and the paint film bonding strength of the test coil is detected. If the paint film bonding strength meets the requirements, the water-based paint can be used for dipping, otherwise it cannot be used.

[0054] The obtained test coil is immersed in water-based paint for dipping treatment to simulate the motor cell dipping treatment. After baking, the water-based paint can be solidified. Then, after sufficient cooling, the adhesion strength of the paint film can be tested. When the paint film strength meets the requirements, water-based paint can be used for dipping, thereby effectively reducing the risk of coil short circuit failure in the motor cell.

[0055] Specifically,

[0056] In this embodiment, the number of coils of the enameled wire to be made is calculated by the following formula:

[0057]

[0058] In the above formula,

[0059] d is the diameter of the enameled wire;

[0060] N is the number of coils.

[0061] The larger the diameter, the fewer turns are required. Different wire diameters have different requirements for bonding strength. The larger the wire diameter, the higher the bonding strength requirement.

[0062] In this embodiment, the step of twisting the loop includes:

[0063] The loop sample is twisted several times from the middle position so that the loop sample forms an 8-shaped test coil, the middle of the test coil is the twisted line segment, and the two sides of the test coil are the coil segments.

[0064] The coil sample is made into an 8-shaped shape so that there are two coil segments, which is convenient for twisting by hand. Specifically, the coil sample is twisted 2.5 turns from the middle, and then rotated half a turn after the twisting is completed to obtain a sample of 8 bytes. Repeat the above steps to make at least 5 test coils for testing to ensure the validity and accuracy of the test data. The finished samples are numbered and recorded in the table.

[0065] In this embodiment, the coil sample is made on an intelligent high-voltage paint film continuity tester. The intelligent high-voltage paint film continuity tester is an existing instrument. Generally, every 10-meter coil sample is equivalent to making 40 coils.

[0066] In this embodiment, the water-based paint is prepared by mixing water-soluble insulating impregnating paint and water, and the weight ratio of the water-soluble insulating impregnating paint to water is 1:1.5.

[0067] The water added to the water-soluble insulating impregnating varnish will be evaporated during the subsequent baking. The water is only used to control the viscosity and adhesion of the configuration solvent, control the immersion time of the enameled wire, and ensure the effectiveness of the test.

[0068] Because water-based paint has a strong odor and is highly volatile, you must wear a gas mask and rubber gloves throughout chemical experiments to prevent direct contact with chemical liquids.

[0069] In this embodiment, the test coil is immersed in the water-based paint for 250 seconds.

[0070] This varnishing time can ensure that the test coil can be well varnished.

[0071] In this embodiment, the test coil is baked at a temperature of 200° C. and a baking time of 60 minutes.

[0072] The baking temperature and baking time can effectively cure the paint film without affecting the strength of the paint film.

[0073] In this embodiment, the time for cooling the test coil is 10 minutes.

[0074] This time allows the paint film to cool sufficiently.

[0075] In this embodiment, the paint film bonding strength of the test coil is detected in the following manner, including: recording the weight of the test coil before dipping in paint as M1, recording the weight of the test coil after dipping in paint, baking and cooling as M2, calculating the paint film weight △M=M2-M1, and judging the paint film bonding strength according to the paint film weight, wherein the greater the paint film weight, the greater the paint film bonding strength.

[0076] By first recording the weight of the coil before immersion in paint, and then recording the weight of the coil after immersion in paint, the corresponding paint film weight can be obtained by subtracting the two. If the paint film weight is larger, it means that there is more paint film bonded to the coil, which means that the paint film bonding strength is greater.

[0077] In this embodiment, the paint film bonding strength of the test coil is also tested in the following manner, including: twisting the test coil in the opposite direction of the twisting direction when making the coil sample, observing the looseness of the test coil; if the coil is not loose, the paint film bonding strength meets the production requirements, otherwise it does not meet the requirements.

[0078] By twisting in the opposite direction, the bonding strength of the paint film can be observed. If the bonding strength of the paint film is not enough, twisting in the opposite direction will cause looseness. If the bonding strength of the paint film is sufficient, it will not be affected even if twisting in the opposite direction, and the ring sample will not become loose.

[0079] Example 2

[0080] The test method for the bonding strength of the paint film on the enameled wire coil disclosed in this embodiment is as follows: Figure 1-2 As shown, the following steps are included:

[0081] Obtaining the enameled wire for making the motor coil, and calculating the number of coils required to be made of the enameled wire;

[0082] In order to accurately match the application environment, the number of coils required is calculated based on the actual motor and the characteristics of the enameled wire.

[0083] The enameled wire is made into a loop sample, and then the loop sample is twisted to separate the loop sample into a test coil having a twisted line segment and a coil segment, wherein the twisted line segment is composed of a plurality of enameled wire segments twisted together, and the coil segment is composed of a plurality of enameled wire coils aligned and stacked;

[0084] According to the number of coils obtained above, the number of coils is made into a coil sample, which is a plurality of coils wound together. Subsequently, the coil sample is partially twisted so that the coil sample produces a twisted segment and a coil segment, which can represent the actual winding method in the motor. The twisted coil is used as a test coil.

[0085] The test coil is placed in water-based paint for dipping, the dipped test coil is taken out and baked, and then the test coil is cooled, and the paint film bonding strength of the test coil is detected. If the paint film bonding strength meets the requirements, the water-based paint can be used for dipping, otherwise it cannot be used.

[0086] The obtained test coil is immersed in water-based paint for dipping treatment to simulate the motor cell dipping treatment. After baking, the water-based paint can be solidified. Then, after sufficient cooling, the adhesion strength of the paint film can be tested. When the paint film strength meets the requirements, water-based paint can be used for dipping, thereby effectively reducing the risk of coil short circuit failure in the motor cell.

[0087] Specifically,

[0088] In this embodiment, the number of coils of the enameled wire to be made is calculated by the following formula:

[0089]

[0090] In the above formula,

[0091] d is the diameter of the enameled wire;

[0092] N is the number of coils.

[0093] The larger the diameter, the fewer turns are required. Different wire diameters have different requirements for bonding strength. The larger the wire diameter, the higher the bonding strength requirement.

[0094] In this embodiment, the step of twisting the loop includes:

[0095] The loop sample is twisted several times from the middle position so that the loop sample forms an 8-shaped test coil, the middle of the test coil is the twisted line segment, and the two sides of the test coil are the coil segments.

[0096] The coil sample is made into an 8-shaped shape so that there are two coil segments, which is convenient for twisting by hand. Specifically, the coil sample is twisted 2.5 turns from the middle, and then rotated half a turn after the twisting is completed to obtain a sample of 8 bytes. Repeat the above steps to make at least 5 test coils for testing to ensure the validity and accuracy of the test data. The finished samples are numbered and recorded in the table.

[0097] In this embodiment, the coil sample is made on an intelligent high-voltage paint film continuity tester. The intelligent high-voltage paint film continuity tester is an existing instrument. Generally, every 10-meter coil sample is equivalent to making 40 coils.

[0098] In this embodiment, the water-based paint is prepared by mixing water-soluble insulating impregnating paint and water, and the weight ratio of the water-soluble insulating impregnating paint to water is 1:2.

[0099] The water added to the water-soluble insulating impregnating varnish will be evaporated during the subsequent baking. The water is only used to control the viscosity and adhesion of the prepared solvent, control the immersion time of the enameled wire, and ensure the effectiveness of the test.

[0100] Because water-based paint has a strong odor and is highly volatile, you must wear a gas mask and rubber gloves throughout chemical experiments to prevent direct contact with chemical liquids.

[0101] In this embodiment, the test coil is immersed in the water-based paint for 300 seconds.

[0102] This varnishing time can ensure that the test coil can be well varnished.

[0103] In this embodiment, the test coil is baked at a temperature of 210° C. and a baking time of 70 minutes.

[0104] The baking temperature and baking time can effectively cure the paint film without affecting the strength of the paint film.

[0105] In this embodiment, the time for cooling the test coil is 15 minutes.

[0106] This time allows the paint film to cool sufficiently.

[0107] In this embodiment, the paint film bonding strength of the test coil is detected in the following manner, including: recording the weight of the test coil before dipping in paint as M1, recording the weight of the test coil after dipping in paint, baking and cooling as M2, calculating the paint film weight △M=M2-M1, and judging the paint film bonding strength according to the paint film weight, wherein the greater the paint film weight, the greater the paint film bonding strength.

[0108] By first recording the weight of the coil before immersion in paint, and then recording the weight of the coil after immersion in paint, the corresponding paint film weight can be obtained by subtracting the two. If the paint film weight is larger, it means that there is more paint film bonded to the coil, which means that the paint film bonding strength is greater.

[0109] In this embodiment, the paint film bonding strength of the test coil is also tested in the following manner, including: twisting the test coil in the opposite direction of the twisting direction when making the coil sample, observing the looseness of the test coil; if the coil is not loose, the paint film bonding strength meets the production requirements, otherwise it does not meet the requirements.

[0110] By twisting in the opposite direction, the bonding strength of the paint film can be observed. If the bonding strength of the paint film is not enough, twisting in the opposite direction will cause looseness. If the bonding strength of the paint film is not enough, even twisting in the opposite direction will not affect it, and the ring sample will not become loose.

[0111] Example 3

[0112] The test method for the bonding strength of the paint film on the enameled wire coil disclosed in this embodiment is as follows: Figure 1-2 As shown, the following steps are included:

[0113] Obtaining the enameled wire for making the motor coil, and calculating the number of coils required to be made of the enameled wire;

[0114] In order to accurately match the application environment, the number of coils required is calculated based on the actual motor and the characteristics of the enameled wire.

[0115] The enameled wire is made into a loop sample, and then the loop sample is twisted to separate the loop sample into a test coil having a twisted line segment and a coil segment, wherein the twisted line segment is composed of a plurality of enameled wire segments twisted together, and the coil segment is composed of a plurality of enameled wire coils aligned and stacked;

[0116] According to the number of coils obtained above, the number of coils is made into a coil sample, which is a plurality of coils wound together. Subsequently, the coil sample is partially twisted so that the coil sample produces a twisted segment and a coil segment, which can represent the actual winding method in the motor. The twisted coil is used as a test coil.

[0117] The test coil is placed in water-based paint for dipping, the dipped test coil is taken out and baked, and then the test coil is cooled, and the paint film bonding strength of the test coil is detected. If the paint film bonding strength meets the requirements, the water-based paint can be used for dipping, otherwise it cannot be used.

[0118] The obtained test coil is immersed in water-based paint for dipping treatment to simulate the motor cell dipping treatment. After baking, the water-based paint can be solidified. Then, after sufficient cooling, the adhesion strength of the paint film can be tested. When the paint film strength meets the requirements, water-based paint can be used for dipping, thereby effectively reducing the risk of coil short circuit failure in the motor cell.

[0119] Specifically,

[0120] In this embodiment, the number of coils of the enameled wire to be made is calculated by the following formula:

[0121]

[0122] In the above formula,

[0123] d is the diameter of the enameled wire;

[0124] N is the number of coils.

[0125] The larger the diameter, the fewer turns are required. Different wire diameters have different requirements for bonding strength. The larger the wire diameter, the higher the bonding strength requirement.

[0126] In this embodiment, the step of twisting the loop includes:

[0127] The loop sample is twisted several times from the middle position so that the loop sample forms an 8-shaped test coil, the middle of the test coil is the twisted line segment, and the two sides of the test coil are the coil segments.

[0128] The coil sample is made into an 8-shaped shape so that there are two coil segments, which is convenient for twisting by hand. Specifically, the coil sample is twisted 2.5 turns from the middle, and then rotated half a turn after the twisting is completed to obtain a sample of 8 bytes. Repeat the above steps to make at least 5 test coils for testing to ensure the validity and accuracy of the test data. The finished samples are numbered and recorded in the table.

[0129] In this embodiment, the coil sample is made on an intelligent high-voltage paint film continuity tester. The intelligent high-voltage paint film continuity tester is an existing instrument. Generally, every 10-meter coil sample is equivalent to making 40 coils.

[0130] In this embodiment, the water-based paint is prepared by mixing water-soluble insulating impregnating paint and water, and the weight ratio of the water-soluble insulating impregnating paint to water is 1:1.2.

[0131] The water added to the water-soluble insulating impregnating varnish will be evaporated during the subsequent baking. The water is only used to control the viscosity and adhesion of the prepared solvent, control the immersion time of the enameled wire, and ensure the effectiveness of the test.

[0132] Because water-based paint has a strong odor and is highly volatile, you must wear a gas mask and rubber gloves throughout chemical experiments to prevent direct contact with chemical liquids.

[0133] In this embodiment, the test coil is immersed in the water-based paint for 200 seconds.

[0134] This varnishing time can ensure that the test coil can be well varnished.

[0135] In this embodiment, the test coil is baked at a temperature of 150° C. and a baking time of 50 minutes.

[0136] The baking temperature and baking time can effectively cure the paint film without affecting the strength of the paint film.

[0137] In this embodiment, the time for cooling the test coil is 8 minutes.

[0138] This time allows the paint film to cool sufficiently.

[0139] In this embodiment, the paint film bonding strength of the test coil is detected in the following manner, including: recording the weight of the test coil before dipping in paint as M1, recording the weight of the test coil after dipping in paint, baking and cooling as M2, calculating the paint film weight △M=M2-M1, and judging the paint film bonding strength according to the paint film weight, wherein the greater the paint film weight, the greater the paint film bonding strength.

[0140] By first recording the weight of the coil before immersion in paint, and then recording the weight of the coil after immersion in paint, the corresponding paint film weight can be obtained by subtracting the two. If the paint film weight is larger, it means that there is more paint film bonded to the coil, which means that the paint film bonding strength is greater.

[0141] In this embodiment, the paint film bonding strength of the test coil is also tested in the following manner, including: twisting the test coil in the opposite direction of the twisting direction when making the coil sample, observing the looseness of the test coil; if the coil is not loose, the paint film bonding strength meets the production requirements, otherwise it does not meet the requirements.

[0142] By twisting in the opposite direction, the bonding strength of the paint film can be observed. If the bonding strength of the paint film is not enough, twisting in the opposite direction will cause looseness. If the bonding strength of the paint film is not enough, even twisting in the opposite direction will not affect it, and the ring sample will not become loose.

[0143] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps described in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0144] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0145] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0146] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0147] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the bonding strength of a paint film on an enameled wire coil, characterized in that: The following steps are involved: Obtaining the enameled wire for making the motor coil, and calculating the number of coils required to be made of the enameled wire; The enameled wire is made into a loop sample, and then the loop sample is twisted to make the loop sample be set as a test coil having a twisted line segment and a coil segment, wherein the twisted line segment is composed of a plurality of enameled wire segments twisted, and the coil segment is composed of a plurality of enameled wire coils stacked; The test coil is placed in water-based paint for immersion treatment, the test coil after immersion is taken out for baking, and then the test coil is cooled, and the paint film bonding strength of the test coil is tested. If the paint film bonding strength meets the requirements, the corresponding water-based paint can be used for immersion, otherwise it cannot be used.

2. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The number of coils required to be made of the enameled wire is calculated by the following formula: In the above formula, d is the diameter of the enameled wire; N is the number of coils.

3. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The steps of twisting the loop sample include: The loop sample is twisted several times from the middle position so that the loop sample forms an 8-shaped test coil, the middle of the test coil is the twisted line segment, and the two sides of the test coil are the coil segments.

4. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The circle sample is prepared on an intelligent high-voltage paint film continuity tester.

5. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The water-based paint is prepared by mixing water-soluble insulating impregnating paint and water, and the weight ratio of the water-soluble insulating impregnating paint to water is 1:1.2-2.

6. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The test coil is immersed in the water-based paint for 200s to 300s.

7. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The test coil is baked at a temperature of 150° C. to 210° C., and the baking time is 50 min to 70 min.

8. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The time for cooling the test coil is 8 minutes to 15 minutes.

9. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 1, characterized in that: The paint film bonding strength of the test coil is detected in the following manner, including: recording the weight of the test coil before being dipped in paint as M1, recording the weight of the test coil after being dipped in paint, baked and cooled as M2, calculating the paint film weight △M=M2-M1, and judging the paint film bonding strength according to the paint film weight, wherein the greater the paint film weight, the greater the paint film bonding strength.

10. The method for testing the bonding strength of the paint film on the enameled wire coil according to claim 9, characterized in that: The paint film bonding strength of the test coil is also tested in the following manner, including: twisting the test coil in the opposite direction of the twisting direction when making the coil sample, observing the looseness of the test coil. If the coil is not loose, the paint film bonding strength meets the production requirements, otherwise it does not meet the requirements.

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