Paint dripping method of stator winding, stator and motor

Abstract

The invention provides a paint dripping method of a stator winding, a stator and a motor, and belongs to the technical field of motor manufacturing. The paint dripping method comprises the following steps that (1) the stator is placed in air to be preheated; (2) the stator is placed on paint dripping equipment, a winding of the stator is communicated with a power source, then the winding is electrically heated to 100 DEG C or above and lower than 130 DEG C, and paint dripping treatment is carried out under the heat preservation condition; (3) electrically heating the winding to 130 DEG C or above and 150 DEG C or below, and carrying out gelation treatment under a heat preservation condition; and (4) electrically heating the winding to 150-170 DEG C, and carrying out curing treatment under a heat preservation condition. According to the paint dripping method, the winding is electrically heated in the processes of paint dripping treatment, gelation treatment and curing treatment, so that the winding has corresponding appropriate temperatures in different stages, the filling rate is increased, damping is increased, namely, paint hanging uniformity is improved, and the NVH problem of the motor is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of motor manufacturing, and in particular relates to a paint dripping method for a stator winding, a stator and a motor. Background Art

[0002] The insulation treatment of the stator winding is a very important step in the production process of the motor stator, which is directly related to the service life of the motor. At present, small and medium-sized motor factories generally use the dripping paint method to paint the winding.

[0003] The traditional paint dripping method is to first heat the air in an oven, preheat the stator by conduction, and then drip paint on the winding, and obtain an insulating winding after the insulating paint is gelled and cured. However, this traditional paint dripping method gradually cools down the stator during the paint dripping, gelling and curing stages, resulting in uneven paint application, which is manifested in a low filling rate of the insulating paint and low damping of the stator. All gaps in the winding are to be filled and cured into a whole by the insulating paint. Low filling rate and / or low damping will cause loose electromagnetic wires to vibrate and generate noise due to electromagnetic effects; in addition, if the paint is unevenly applied, it will also increase high-order modes, resulting in worsening of motor noise, vibration and harshness (hereinafter referred to as NVH). Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the embodiments of the present invention provide a stator winding paint dripping method, a stator and a motor, wherein the paint dripping method can keep the winding at a suitable temperature during the paint dripping, gelling and curing stages, thereby improving the filling rate and damping, making the paint even, and thus improving the NVH problem of the motor.

[0005] The paint dripping method of the stator winding according to the embodiment of the present invention comprises the following steps:

[0006] (1) placing the stator in air for preheating;

[0007] (2) placing the stator on a paint dripping device, connecting the stator winding to a power source, and then electrically heating the winding to a temperature above 100° C. and below 130° C., and performing a paint dripping treatment under a heat preservation condition;

[0008] (3) electrically heating the winding to a temperature of 130° C. or higher and lower than 150° C. and performing a gelation treatment under heat preservation conditions;

[0009] (4) The winding is electrically heated to 150-170° C. and cured under heat preservation conditions.

[0010] The advantages and technical effects brought by the paint dripping method of the embodiment of the present invention are as follows:

[0011] Compared with the traditional paint dripping process, the paint dripping method of the embodiment of the present invention electrically heats the winding during the paint dripping treatment stage, the gelation treatment stage and the curing treatment stage, which plays a role in heat preservation of the winding, so that the winding can maintain a corresponding suitable temperature at different stages, thereby improving the filling rate and damping, that is, improving the uniformity of paint application, thereby improving the NVH problem of the motor.

[0012] In some embodiments, in step (1), the temperature of the preheating treatment is 110-180° C.; and / or the time of the preheating treatment is 1-3 hours.

[0013] In some embodiments, in step (2), the winding is electrically heated to a temperature above 110° C. and below 130° C., and a paint dripping treatment is performed under heat preservation conditions.

[0014] In some embodiments, in step (2), the speed of the paint dripping process is 3-15 g / min.

[0015] In some embodiments, in step (2), the heat preservation is continued for 3-20 minutes after the paint dripping treatment is completed.

[0016] In some embodiments, in step (3), the gelation treatment time is 10-15 minutes.

[0017] In some embodiments, in step (4), the curing treatment time is 1-2 hours.

[0018] In some embodiments, in steps (2)-(4), the insulation conditions are all constant temperature insulation.

[0019] The embodiment of the present invention further provides a stator, which is prepared by the paint dripping method of the embodiment of the present invention.

[0020] The advantages and technical effects brought by the stator of the embodiment of the present invention are as follows:

[0021] The stator of the embodiment of the present invention is painted evenly, the insulation layer filling rate on the surface of the stator winding is high, and the damping of the stator is also high. When it is used in a motor, it is helpful to improve the NVH problem of the motor.

[0022] An embodiment of the present invention further provides a motor, comprising the stator of the embodiment of the present invention.

[0023] The advantages and technical effects brought by the motor of the embodiment of the present invention are as follows:

[0024] The NVH problem of the motor in the embodiment of the present invention is effectively optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the 16th order sound pressure level curve of the motors of Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0027] An embodiment of the present invention provides a method for dripping paint on a stator winding, comprising the following steps:

[0028] (1) Preheat the stator in air;

[0029] (2) placing the stator on a paint dripping device, connecting the stator winding to a power source, and then electrically heating the winding to a temperature above 100° C. and below 130° C., and performing a paint dripping treatment under a heat preservation condition;

[0030] (3) electrically heating the winding to a temperature of 130° C. or higher and lower than 150° C. and performing a gelation treatment under heat preservation conditions;

[0031] (4) The winding is electrically heated to 150-170° C. and cured under heat preservation conditions.

[0032] The paint dripping method of the embodiment of the present invention can be divided into four stages, namely, a preheating treatment stage, a paint dripping treatment stage, a gelling treatment stage, and a curing treatment stage. Compared with the traditional paint dripping process, the paint dripping method of the embodiment of the present invention electrically heats the winding in the paint dripping treatment stage, the gelling treatment stage, and the curing treatment stage, which plays a role in heat preservation of the winding and enables the winding to maintain a corresponding suitable temperature at different stages, thereby improving the filling rate of the insulating paint and the damping of the stator, that is, improving the uniformity of the paint, and then improving the NVH problem of the motor.

[0033] In the paint dripping method of the embodiment of the present invention, the preheating treatment in step (1) can drive away the moisture in the winding and shorten the electric heating time of the subsequent step (2). The preheating temperature is set according to the physicochemical properties of the insulating paint used in the subsequent step (2). Preferably, in some embodiments, the temperature of the preheating treatment in step (1) is 110-180°C, such as 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, etc., which can effectively drive away the moisture in the winding and shorten the electric heating time of the subsequent step (2). When the temperature of the preheating treatment is too low, it is not conducive to shortening the electric heating time of the subsequent step (2); when the temperature of the preheating treatment is too high, it is not conducive to reducing costs and increasing efficiency. Preferably, in some embodiments, the time of the preheating treatment in step (1) is 1-3h, such as 1h, 1.5h, 2h, 2.5h, 3h, etc. When the preheating time is too short, it is not conducive to driving away the moisture in the winding, and thus is not conducive to the uniformity of subsequent paint dripping; and when the preheating time is too long, it is not conducive to reducing costs and increasing efficiency.

[0034] It should be understood that the temperature of the dripping treatment in step (2) also needs to be set according to the physical and chemical properties of the insulating paint used. Insulating paint is also called insulating resin, varnish or solvent-free paint. The main component of insulating paint is generally an unbranched linear resin or a branched linear resin, such as at least one of epoxy resin, polyimide resin, polyurethane, etc., and is added with hardeners, diluents, accelerators, cross-linking agents and other components. The insulating paint itself is a viscous liquid with fluidity. The embodiment of the present invention finds that when the temperature of the dripping paint treatment is above 100°C and below 130°C, such as 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, 122°C, 124°C, 116°C, 128°C, etc., it is conducive to the viscosity of the dripped insulating paint to decrease and the fluidity to increase. Under the dual effects of gravity and capillary penetration between turns, the insulating paint quickly penetrates and fills all the winding turns, even the small part of the coil can penetrate, the filling rate is high, the damping is also high, that is, the paint hanging effect is uniform. When the temperature of the dripping paint treatment is lower than 100°C, the viscosity of the insulating paint is too small, and the loss of the insulating paint during the dripping process is too much; when the temperature of the dripping paint treatment is higher than 130°C, the insulating paint will gel, resulting in increased viscosity, poor fluidity, and poor uniformity of paint hanging.

[0035] In some embodiments, in step (2), the winding is electrically heated to a temperature above 110°C and below 130°C, and the paint dripping treatment is performed under heat preservation conditions, that is, the temperature of the paint dripping treatment in step (2) is above 110°C and below 130°C, such as 110°C, 112°C, 114°C, 116°C, 118°C, 120°C, 122°C, 124°C, 116°C, 128°C, etc., which is conducive to the winding transitioning to the temperature required for the gelation treatment stage in the subsequent step (3). When the temperature of the paint dripping treatment in step (2) is too low, it is not conducive to the winding transitioning to the temperature required for the gelation treatment stage in the subsequent step (3); and when the temperature of the paint dripping treatment in step (2) is too high, the insulating paint is easily gelled, resulting in increased viscosity, which is not conducive to improving the fluidity of the insulating paint, and further not conducive to improving the uniformity of the paint.

[0036] Paint dripping treatment is an important part of determining the quality of paint dripping. It should be understood that at this stage, the paint dripping quality can be optimized by optimizing the three process parameters of rotation speed, tilt angle and paint dripping amount.

[0037] For example, the speed of the winding can be set to 10-30rpm. The paint dripping is carried out under the condition that the stator rotates. The speed is related to the diameter of the stator. The speed is relatively low for a relatively large diameter, and the speed is relatively high for a relatively small diameter. Therefore, the appropriate speed can be selected according to the type and size of the stator, which can not only make the insulating paint penetrate quickly, but also keep the inner and outer circles of the stator's iron core from being contaminated. When the speed of the winding is too low, it is not conducive to improving the paint coating efficiency. When the speed of the winding is too high, it is not conducive to improving the paint coating effect. It should be noted that when the winding rotates with the rotating device, the power supply connected to the winding will also rotate synchronously.

[0038] In addition, in step (2), the paint dripping treatment can be carried out by using an inclined paint dripping method, and optionally, the paint dripping treatment can also be carried out in combination with a horizontal paint dripping method. The inclined paint dripping method is to drip the paint on the winding while maintaining a certain inclination angle, and the inclination can accelerate the flow rate of the insulating paint; the horizontal paint dripping method is to drip the paint on the winding in a horizontal state; the insulating paint relies on gravity and capillary phenomena to penetrate into the interior of the coil. For stators of larger sizes, the paint dripping treatment can be preferably carried out by combining the inclined paint dripping method with the horizontal paint dripping method, which is conducive to the paint liquid fully filling the gap in the slot. In the inclined paint dripping method, it is preferred to drip the paint on the winding at an inclination angle of 5-20°. The inclination angle refers to the angle between the stator and the horizontal plane. When the inclination angle is too low, it is not conducive to accelerating the flow rate of the insulating paint. When the inclination angle is too large, it is not conducive to improving the uniformity of the paint hanging.

[0039] In addition, in step (2), the amount of paint dripping needs to be specifically set according to the length and slot shape of the stator, and the dripped insulating paint is required to be completely absorbed into the coil to form a completely impregnated state without air gaps. Reasonable control of the amount of paint dripping becomes an important indicator for process implementation. If the amount of paint dripping is too little, it is difficult to form an insulating layer of ideal thickness; if the amount of paint dripping is too much, it cannot be completely absorbed, and the excess insulating paint will flow inside and outside the iron core and need to be scraped off. In addition, excessive paint dripping can easily cause uneven adhesion of the insulating paint, affect the rotation of the coil, and cause inertia imbalance, or easily cause accumulation of insulating paint, and cause cracking during curing.

[0040] The specific amount of paint dripping should be determined by experiment after the type of insulating paint is selected, according to the structure and size of the stator. Using a metering pump to control the amount of paint dripping can ensure that each stator has the same amount of paint dripping to ensure quality. After the amount of paint dripping is determined, the paint dripping speed is determined by experiment, that is, the speed at which the dripped insulating paint can be absorbed without being lost at a certain speed, which is generally 3-15g / min. After the amount of paint dripping and the speed of paint dripping are determined, the paint dripping time can be calculated according to the principle of paint dripping amount = paint dripping speed × paint dripping time.

[0041] Insulating varnish is originally a viscous liquid that can flow. Under the gelation temperature condition, the molecules react with each other, which is manifested as the viscosity of the system gradually increasing, and the system is transformed into an elastic gel-like substance, and the chemical properties also change suddenly. This phenomenon is called gelation. When designing the temperature of the gelation treatment in step (3), the type of insulating varnish and the shape and size of the stator should be considered comprehensively. In addition, since the insulating varnish releases heat during gelation, especially when dripping, the gelation speed is fast, so the heat release is also strong. Therefore, it is also necessary to consider the heat release phenomenon of different types of insulating varnish to set the temperature of the gelation treatment.

[0042] Preferably, in some embodiments, in step (2), after dripping the insulating paint, it is not recommended to immediately perform the gelation treatment of step (3), but it is desired that the winding continue to rotate for 3-20 minutes under the insulation conditions of step (2), so that the insulating paint absorbed by the winding can penetrate and distribute more evenly during the continuous rotation process.

[0043] In the paint dripping method of the embodiment of the present invention, in step (3), the winding is electrically heated to a temperature of 130°C or higher and lower than 150°C, and gelation treatment is performed under heat preservation conditions, that is, the temperature of the gelation treatment in step (3) is 130°C or higher and lower than 150°C, such as 130°C, 132°C, 134°C, 136°C, 138°C, 140°C, 142°C, 144°C, 146°C, 148°C, etc., which can not only shorten the time required for the gelation process and improve production efficiency, but also prevent the paint film from cracking and improve the quality of the paint. When the temperature of the gelation treatment in step (3) is lower than 130°C, the time required for the gelation process is too long, which is not conducive to improving production efficiency. Since the insulating paint will cause volume shrinkage during the gelation process, when the temperature of the gelation treatment is above 150°C, the shrinkage rate is too large, which is easy to cause cracking on both sides of the notch and the contact between the core and the tip wedge. In addition, since the current insulating varnish usually contains some volatile diluents or hardeners with a low boiling point, volatilization will occur during the gelation process. When the gelation treatment temperature is above 150°C, the gelation reaction is more violent. The paint liquid on the surface is forming a film, and the volatile components inside are about to come out, which can easily break through the paint film to form bubbles.

[0044] In some embodiments, in step (3), the gelation treatment time is 10-15 minutes, such as 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc., which can make the insulating paint completely gelled and improve production efficiency. When the gelation treatment time in step (3) is too short, it is not conducive to complete gelation of the insulating paint. When the gelation treatment time in step (3) is too long, it is not conducive to cost reduction and efficiency improvement.

[0045] Gelation is a manifestation of the reaction between the molecules of the insulating paint, but it does not mean that the molecular reaction at this stage is complete, so the gelation treatment is not the final completion of the paint dripping process. The insulating paint after the gelation treatment must also undergo a subsequent curing treatment in step (4) to allow the molecules to continue to react to the final state and obtain an ideal insulating layer. In the paint dripping method of the embodiment of the present invention, the temperature of the curing treatment in step (4) is 150-170°C, for example, 150°C, 152°C, 154°C, 156°C, 158°C, 160°C, 162°C, 164°C, 166°C, 168°C, 170°C, etc., which can increase the curing speed of the insulating paint, thereby improving production efficiency, and at the same time ensure that the winding will not produce insulation failure. When the curing temperature in step (4) is too low, the required curing time is too long, which is not conducive to improving production efficiency. When the curing temperature in step (4) is too high, it is not conducive to reducing the risk of winding insulation failure.

[0046] The time of curing treatment in step (4) mainly depends on the type of insulating paint used and the temperature of curing treatment adopted. As time goes by at a certain curing treatment temperature, the curing reaction of the insulating paint becomes more and more perfect, and various properties are constantly improved, and finally reaches a saturation point, that is, the reaction is complete and the performance no longer changes with the extension of time. Usually, when its various properties can meet the basic requirements of use, it can be considered that the curing is basically completed, and further curing can be left to be completed in the future operation. This is also the reason why the dripping paint process does not require the insulating paint to be completely cured. Therefore, in some embodiments, the insulation time in step (4) is 1-2h, such as 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc., which is conducive to perfecting the curing reaction and improving the quality and efficiency of painting.

[0047] In the paint dripping method of the embodiment of the present invention, each of the steps (2)-(4) is heated to a preset temperature and kept warm, which means that the insulation temperature of each stage only needs to be maintained within the preset temperature range, and can be either kept warm under constant temperature conditions or kept warm under non-constant temperature conditions. Preferably, in some embodiments, in step (2), a constant temperature is maintained during the insulation process, and constant temperature electric heating is convenient for controlling the temperature of the paint dripping process to always be maintained at the optimal flow temperature of the insulating paint, ensuring that it has the best fluidity, so that the paint hanging effect is uniform, thereby optimizing the motor NVH. Preferably, in some embodiments, in step (3), a constant temperature is maintained during the insulation process, and constant temperature electric heating is convenient for controlling the temperature of the gelation process to always be at the optimal gelation temperature of the insulating paint, so that the paint hanging effect is uniform, thereby optimizing the motor NVH. Preferably, in some embodiments, in step (4), a constant temperature is maintained during the insulation process, and constant temperature electric heating is convenient for controlling the temperature of the curing process to always be at the optimal curing temperature of the insulating paint, so that the paint hanging effect is uniform, thereby optimizing the motor NVH.

[0048] In some embodiments, in steps (2)-(4), during the process of heating to the required temperature at each stage, the heating rate is 2-5°C / s, such as 2°C / s, 3°C / s, 4°C / s, 5°C / s, etc. When the heating rate is too slow, it is not conducive to quickly adjusting the temperature of the winding; and when the heating rate is too fast, it is not conducive to the temperature balance between the core and the winding. It should be understood that the temperature of the winding can be monitored by an infrared measuring instrument with a temperature control accuracy of ±5°C, which is convenient for accurately controlling the temperature of the winding.

[0049] The embodiment of the present invention further provides a stator, which is prepared by the paint dripping method of the embodiment of the present invention. The stator of the embodiment of the present invention has a good uniformity of the insulation layer on the surface of the stator winding, which is conducive to improving the NVH problem of the motor.

[0050] The embodiment of the present invention further provides a motor, comprising the stator of the embodiment of the present invention. The motor of the embodiment of the present invention effectively optimizes the NVH problem.

[0051] The present invention is described in detail below with reference to the embodiments and the accompanying drawings.

[0052] The insulating varnish used in the following examples and comparative examples is the 4201 type insulating varnish purchased from Voltatex.

[0053] The stator used in the following embodiments and comparative examples has an outer diameter of 220 mm and a stator stack length of 110 mm, which is suitable for small motors of new energy vehicles.

[0054] The following embodiments and comparative examples use an infrared measuring instrument to automatically monitor the temperature of the winding and the core, and the temperature control accuracy is ±5°C.

[0055] The paint dripping machine used in the following examples and comparative examples is a non-standard customized paint dripping machine purchased from BBS manufacturer.

[0056] Example 1

[0057] A method for dripping paint on a stator winding comprises the following steps:

[0058] (1) Preheat the stator in an oven at 120°C for 1.5 hours;

[0059] (2) The stator is placed on the rotating device of the paint dripping machine and fixed. The rotating device automatically adjusts the clamping angle according to the set stator inclination angle of 15°, and the stator winding is connected to the power supply. Then, the winding is electrically heated to 120°C at a heating rate of 3°C / s, and then the following operations are performed under a constant temperature insulation state: the paint dripping machine drips paint on the winding rotating at a speed of 20 rpm, the paint dripping amount is 116 g, the paint dripping speed is 5 g / min, and the winding is kept rotating for 5 minutes after the paint dripping is completed;

[0060] (3) The winding stops rotating, and the winding is further electrically heated to 140°C at a heating rate of 3°C / s, and then gelled for 12 minutes under constant temperature holding conditions;

[0061] (4) The winding is further electrically heated to 160°C at a heating rate of 3°C / s, and then cured at a constant temperature for 1.5 hours;

[0062] (5) Disconnect the stator and power supply and remove the stator from the paint dripping machine.

[0063] A stator is prepared by the above-mentioned stator winding paint dripping method.

[0064] A motor comprises the above-mentioned stator.

[0065] Example 2

[0066] A method for dripping paint on a rotor stator winding comprises the following steps:

[0067] (1) Preheat the stator in an oven at 110°C for 1.5 hours;

[0068] (2) The stator is placed on the rotating device of the paint dripping machine and fixed. The optional rotating device automatically adjusts the clamping angle according to the set stator inclination angle of 15°, and the stator winding is connected to the power supply. Then the winding is electrically heated to 110°C at a heating rate of 3°C / s, and then the following operations are performed under constant temperature and heat preservation: the paint dripping machine drips paint on the winding rotating at a speed of 20 rpm, the paint dripping amount is 116g, the paint dripping speed is 5g / min, and the winding is kept rotating for 5 minutes after the paint dripping is completed;

[0069] (3) The winding stops rotating, and the winding is further electrically heated to 130°C at a heating rate of 3°C / s, and then gelled for 12 minutes under constant temperature insulation conditions;

[0070] (4) The winding is further electrically heated to 150°C at a heating rate of 3°C / s, and then cured at a constant temperature for 1.5 hours;

[0071] (5) Disconnect the stator and power supply and remove the stator from the paint dripping machine.

[0072] A stator is prepared by the above-mentioned stator winding paint dripping method.

[0073] A motor comprises the above-mentioned stator.

[0074] Example 3

[0075] A method for dripping paint on a stator winding comprises the following steps:

[0076] (1) Preheat the stator in an oven at 130°C for 1.5 hours;

[0077] (2) The stator is placed on the rotating device of the paint dripping machine and fixed. The rotating device automatically adjusts the clamping angle according to the set stator inclination angle of 15°, and the stator winding is connected to the power supply. Then, the winding is electrically heated to 130°C at a heating rate of 3°C / s, and then the following operations are performed under a constant temperature insulation state: the paint dripping machine drips paint on the winding rotating at a speed of 20 rpm, the paint dripping amount is 116 g, the paint dripping speed is 5 g / min, and the winding is kept rotating for 5 minutes after the paint dripping is completed;

[0078] (3) The winding stops rotating, and the winding is further electrically heated to 150°C at a heating rate of 3°C / s, and then gelled for 12 minutes under constant temperature insulation conditions;

[0079] (4) The winding is further electrically heated to 170°C at a heating rate of 3°C / s, and then cured at a constant temperature for 1.5 hours;

[0080] (5) Disconnect the stator and power supply and remove the stator from the paint dripping machine.

[0081] A stator is prepared by the above-mentioned stator winding paint dripping method.

[0082] A motor comprises the above-mentioned stator.

[0083] Comparative Example 1

[0084] A method for dripping paint on a stator winding comprises the following steps:

[0085] (1) Preheat the stator in an oven at 120°C for 1.5 hours;

[0086] (2) The stator is placed on the rotating device of the paint dripping machine and fixed. The rotating device automatically adjusts the clamping angle according to the set stator inclination angle of 15°. The electric heating function of the paint dripping machine is turned off. The following operations are performed under natural conditions: the paint dripping machine drips paint on the winding rotating at a speed of 20 rpm, the paint dripping amount is 116 g, the paint dripping speed is 5 g / min, and the paint dripping is continued to rotate for 5 minutes after the paint dripping is completed;

[0087] (3) Remove the stator from the paint dripping machine and let it stand for 12 hours.

[0088] A stator is prepared by the above-mentioned stator winding paint dripping method.

[0089] A motor comprises the above-mentioned stator.

[0090] Performance Test:

[0091] (1) Damping: The modes of the stators of Examples 1-3 and Comparative Example 1 were measured to obtain damping. The results are shown in Table 1.

[0092] (2) NVH: Bench test was conducted in a semi-anechoic chamber. Working conditions: Working input torque was 300 Nm, maximum speed was 15000 rpm. Analysis speed was 2000-8500 rpm. The 16th order sound pressure level curves of the motors of Examples 1-3 and Comparative Example 1 are shown in Figure 1. Figure 1 shown.

[0093] (3) The stators of Examples 1-3 and Comparative Example 1 were cut and the filling rates of the insulating varnish in the windings were measured. The results are shown in Table 1.

[0094] Table 1. Effects of the paint dripping method of Examples 1-3 and Comparative Example 1

[0095] Fill rate Damping Example 1 96％ 2.85％ Example 2 97％ 3.42％ Example 3 95％ 2.28％ Comparative Example 1 86％ 0.95％

[0096] The uniformity of paint application is specifically measured by the filling rate and damping. It can be seen from Table 1 that, relative to the stator of comparative example 1, the filling rate of insulating paint and the damping of the stator of embodiments 1-3 of the present invention are greatly increased, indicating that the paint dripping method of the stator winding of embodiments 1-3 is more uniform in paint application.

[0097] in addition, Figure 1 The 16th-order sound pressure level curves of the motors of Examples 1-3 and Comparative Example 1 are shown. It can be seen that compared with the motor of Comparative Example 1, the sound levels of the motors of Examples 1-3 are lower, and the NVH problem is effectively improved.

[0098] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0099] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A paint dripping method for stator windings, It is characterized in that The following steps are involved: (1) placing the stator in air for preheating; (2) placing the stator on a paint dripping device, connecting the stator winding to a power source, and then electrically heating the winding to a temperature above 100° C. and below 130° C., and performing a paint dripping treatment under a heat preservation condition; (3) electrically heating the winding to a temperature of 130° C. or higher and lower than 150° C. and performing a gelation treatment under heat preservation conditions; (4) The winding is electrically heated to 150-170° C. and cured under heat preservation conditions.

2. The paint dripping method for stator winding according to claim 1, It is characterized in that In step (1), the temperature of the preheating treatment is 110-180° C.; and / or the time of the preheating treatment is 1-3 hours.

3. The paint dripping method for stator winding according to claim 1, It is characterized in that In step (2), the winding is electrically heated to a temperature above 110° C. and below 130° C., and the paint dripping treatment is performed under heat preservation conditions.

4. The method for dripping paint on a stator winding according to claim 1 or 3, It is characterized in that In step (2), the speed of the paint dripping process is 3-15 g / min.

5. The paint dripping method for stator winding according to claim 1 or 3, It is characterized in that In step (2), the temperature is kept constant for 3-20 minutes after the paint dripping treatment is completed.

6. The method for dripping paint on stator winding according to claim 1, It is characterized in that In step (3), the gelation treatment time is 10-15 minutes.

7. The method for dripping paint on stator winding according to claim 1, It is characterized in that In step (4), the curing treatment time is 1-2 hours.

8. The method for dripping paint on stator winding according to claim 1, It is characterized in that In steps (2)-(4), the insulation conditions are all constant temperature insulation.

9. A stator, It is characterized in that The invention is prepared by the paint dripping method according to any one of claims 1 to 8.

10. A motor, It is characterized in that Comprising the stator as claimed in claim 9.

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