Patent Description:
Stacking forming methods of modern mass-produced motor cores mainly include bolted connection, welding, riveting and adhering. In the adhering mode, silicon steel plates coated with a self-adhesive coating are assembled by surface-fixing to one another, which provides the stacking forming process with the advantages of no pollution, high core fixing strength, low magnetic vibration noise, and high core efficiency. It is especially suitable for situations where other fixing methods will cause distortion or insufficient rigidity, and where riveting or welding is inconvenient.

The current conventional application guidance for silicon steel plates with a self-adhesive coating includes: taking out, as a whole, a core (actually separate plates at that time) punched by a punching machine, placing the core on a clamp under a pressure of <NUM>-<NUM> bar, conveying the core to a heating furnace and heating at <NUM>-<NUM> for <NUM>-<NUM> hr, taking out the core after being cooled, and removing overflowing edges, and thereby a finished core product is obtained. Such process steps lead to relatively low production efficiency, need frequent manual interventions, and cannot achieve fast and continuous automatic operations, thereby resulting in high energy consumption and production operation cost. Not only that, cured silicon steel cores in different batches are different in adhering strength, differences in core thickness, and extruded overflowing edges, and the production stability is not good. Therefore, in the prior art, some researchers have made relevant improvements on stack tooling for increasing production efficiency and improving the curing quality and stability of a core with a self-adhesive coating. However, as the curing and heat preservation time of the core with a coating is not changed, the whole process of core curing from heating in a furnace, heat preservation to cooling and leaving the furnace takes generally about <NUM> hr, and the efficiency is still low as compared with other silicon steel products with a coating.

In the prior art, some researchers have found that if a silicon steel plate core with a self-adhesive coating is quickly heated to a target temperature in a short time, and a corresponding temperature distribution requirement is met thereby, a good adhesive curing effect can also be achieved. Japanese patent publication No. <CIT> proposes to rapidly heat a self-adhesive core via a high-frequency electromagnetic field formed by a high-frequency microwave, and proposes an emission source of a high-frequency microwave and a structure of related heating equipment.

However, the inventor of the present application has found that a high-frequency induction heating method can only be used to heat a silicon steel plate stack with a small size. As the size of a silicon steel plate increases, a heating area is mainly concentrated in a very narrow area of a surface layer of the silicon steel plate due to a skin gathering effect of induction heating, and in a diameter direction of the silicon steel plate, the surface can reach a high temperature instantly, while the interior is mainly heated by heat conduction inward from the surface, such that the internal temperature is relatively low compared with the temperature of the surface, resulting in a big difference in adhering performance between the surface and a core area of the silicon steel plate stack. Therefore, high-frequency induction heating cannot achieve effective heating of large silicon steel plates, and cannot cover a wide range of silicon steel plate specifications.

Induction heating is a method that can achieve efficient and rapid heating. However, the frequency selection has a crucial influence on the heating effect. If a lower frequency is selected, the depth of skin gathering layer of an induction heating eddy current can be increased, but the heating efficiency is lower. If a higher frequency is selected, the depth of skin gathering layer is reduced, and the heating efficiency is higher, but the temperature difference between the surface and the interior of the heated workpiece during heating is greater.

In view of this, it is desired to obtain an induction heating system capable of rapidly curing a silicon steel core with a self-adhesive coating and ensuring the curing quality of core products, thereby being widely applicable to the field of the production of silicon steel cores with a self-adhesive coating.

<CIT> discloses a bonded-type laminated core member manufacturing apparatus comprising an adhesive application unit to apply an adhesive to a material being continuously transferred, and a laminating unit to integrate laminar members laminated within a laminating hole by blanking the material, a laminated core member being manufactured by interlayer adhesion between the laminar members, wherein the laminating unit includes a high-frequency heater to harden the adhesive located between the laminar members, the high-frequency heater including a coil wound on the circumference of a hardening hole which accommodates the laminar members and forming a passage of high-frequency current. <CIT> discloses an induction heating coil device. <CIT> discloses a method for forming an insulating layer formed of ceramic by treating a core having a coated coil wound on it by high-frequency. <CIT> discloses a heating method of a motor rotor, comprising: preparing the motor rotor that needs to be heated, placing the motor rotor in an induction coil of an intermediate frequency generator with <NUM> turns, passing the alternating magnetic field of <NUM>-<NUM> into the induction coil for a duration of <NUM>-<NUM> seconds, taking out the motor rotor and measuring the temperature. <CIT> discloses a positioning and heating curing method after sticking a magnetic tile on a rotor.

One objective of the present invention is providing an induction heating system for rapid curing of a silicon steel core with a self-adhesive coating, the system being capable of rapidly curing a silicon steel core with a self-adhesive coating and ensuring the curing quality of core products and increasing production efficiency, thereby being widely applicable to the field of the production of silicon steel cores with a self-adhesive coating.

To achieve the above objective, the present invention provides an induction heating system for a silicon steel core with a self-adhesive coating according to claim <NUM>. The system includes: an induction heating device, which includes a columnar induction heating coil with a hollow cavity, wherein the induction heating coil carries out induction heating on a silicon steel plate at a medium frequency of <NUM>-<NUM>.

In the technical solution of the present invention, the use of the induction heating coil with a medium frequency of <NUM>-<NUM> for induction heating on a silicon steel plate is applicable to a wide range of silicon steel plate specifications. Considering both rapid curing and ensuring the curing quality of core products, an outer diameter of the silicon steel plate is preferably Φ50-<NUM>, more preferablyΦ50~<NUM>.

Further, the induction heating system of the present invention greatly shortens the curing time of the silicon steel plates, and provides a possibility for automatic production of a silicon steel core with a self-adhesive coating. Therefore, the system further includes: a conveying roller table, with a plurality of stacking molds being conveyed thereon, the stacking molds being used for placing stacked silicon steel plates therein;.

Further, in the induction heating system of the present invention, the feeding and discharging device preferably includes a cantilever beam extending in the horizontal direction, and a manipulator capable of walking along the cantilever beam.

In the technical solution of the present invention, in some embodiments, walking and clamping operations of the manipulator may be controlled by a servo motor. In addition, the cantilever beam may be mounted to a support for placing the conveying roller table.

Still further, in the induction heating system of the present invention, a conveying direction of the conveying roller table and a conveying direction of the feeding and discharging device are preferably perpendicular to each other.

Further, in the induction heating system of the present invention, the temperature measuring element is preferably an infrared temperature measuring element.

Further, in the induction heating system of the present invention, the temperature measuring element is preferably arranged at a middle part of the induction heating coil.

Further, in the induction heating system of the present invention, the loading and unloading device preferably includes:.

In the technical solution of the present invention, the horizontal movable plate is preferably arranged on the base plate and connected with the control device, and the horizontal movable plate is configured to be slidable in the horizontal direction relative to the base plate, so that the loading and unloading device can convey the stacking mold in the horizontal direction to a position directly below the induction heating coil. The vertical displacement adjusting element is arranged on the support and is connected with the control device, so that the loading and unloading device can convey the stacking mold in the vertical direction into the hollow cavity of the induction heating device or moving the stacking mold out of the hollow cavity after the induction heating is completed. In some embodiments, the stacking mold seat may be made of a nonmetal material.

Further, in the induction heating system of the present invention, the stacking mold seat is preferably provided with a pressure sensor, and the pressure sensor is connected with the control device.

In the technical solution of the present invention, the stacking mold seat is preferably provided with a pressure sensor to detect a pressure on the stacking mold seat in real time, and the pressure sensor is connected with the control device, so that the control device controls a compaction degree of the silicon steel plates based on a pressure value transmitted by the pressure sensor.

Further, in the induction heating system of the present invention, the induction heating system preferably further includes:.

In the technical solution of the present invention, in some embodiments, the induction heating device may further include a fixing rod connected with the induction heating device support, and the compacting force adjusting element may be connected with the fixing rod, so that the compacting force adjusting element is mounted to the induction heating device support through the fixing rod. The distance measuring element is connected with the compacting force adjusting element so as to be mounted to the induction heating device support through the compacting force adjusting element. In addition, in some embodiments, the compaction disk may be made of a nonmetal material.

Correspondingly, another objective of the present invention is providing an induction heating method for rapid curing of a silicon steel core with a self-adhesive coating, the method being capable of rapidly curing a silicon steel core with a self-adhesive coating and ensuring the curing quality of core products and increasing production efficiency, thereby being widely applicable to the field of the production of silicon steel cores with a self-adhesive coating.

To achieve the above objective, the present invention provides an induction heating method for a silicon steel core with a self-adhesive coating according to claim <NUM>. Optionally, in the induction heating method for a silicon steel core with a self-adhesive coating according to claim <NUM>, the induction heating coil is used to carry out induction heating on the stacked silicon steel plates at a medium frequency of <NUM>-<NUM>, the method comprising the following steps: compacting the stacked silicon steel plates, carrying out induction heating, by the induction heating coil, on the stacked silicon steel plates at a medium frequency of <NUM>-<NUM>, and measuring the temperature of the silicon steel plates in real time, and stopping heating by the induction heating coil when the silicon steel plates reach a target heating temperature.

In the present invention, heating can be stopped whenever the silicon steel plates reach the target heating temperature, thereby greatly shortening the heating time of the silicon steel core with a self-adhesive coating.

In the technical solution of the present invention, in some embodiments, a process of induction heating on silicon steel plates stacked inside a stacking mold by using the induction heating system of the present invention may be as follows:.

Rapid induction heating and self-adhesive curing of the silicon steel plates are accomplished by the above-mentioned steps, and the conveying roller table continues operation, and the next round of treatment on silicon steel plates may be carried out by repeating the above-mentioned steps.

Compared with the prior art, the induction heating system and method for rapid curing of a silicon steel core with a self-adhesive coating have the following beneficial effects:.

By means of rapid induction heating at a medium frequency, the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention can rapidly cure a silicon steel core with a self-adhesive coating, and can ensure the curing quality of core products and increase production efficiency, thereby being widely applicable to the field of the production of silicon steel cores with a self-adhesive coating.

An induction heating system and method for rapid curing of a silicon steel core with a self-adhesive coating of the present invention is further explained and described below in conjunction with the drawings and specific embodiments. However, the explanation and description do not improperly limit the technical solutions of the present invention.

<FIG> is a structural diagram of the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention in a feeding state in some embodiments. <FIG> is a structural diagram of the feeding and discharging device in some embodiments, in the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention. <FIG> is a structural diagram of an induction heating device in some embodiments, in the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention. <FIG> is a structural diagram of a loading and unloading device in some embodiments, in the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention.

As shown in <FIG>, in some embodiments, the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating in the present invention includes: a conveying roller table <NUM>, a conveying roller table support <NUM>, an induction heating device <NUM>, a feeding and discharging device <NUM>, a loading and unloading device <NUM> and a control device (not shown in the figure). A plurality of stacking molds <NUM> (made of a nonmetal material) are conveyed on the conveying roller table <NUM>, and the stacking molds <NUM> are used for placing stacked silicon steel plates <NUM> therein, a conveying direction of the conveying roller table <NUM> and a conveying direction of the feeding and discharging device <NUM> being perpendicular to each other. The control device is connected with the conveying roller table <NUM>, the feeding and discharging device <NUM> and the loading and unloading device <NUM>, respectively, to control respective operations thereof.

Further referring to <FIG>, <FIG> and <FIG>, in some embodiments, the feeding and discharging device <NUM> conveys the stacking mold <NUM> along a horizontal direction, and includes a cantilever beam <NUM> mounted to the conveying roller table support <NUM> and extending in the horizontal direction, and a manipulator <NUM> capable of walking along the cantilever beam <NUM>. In some embodiments, walking and clamping operations of the manipulator <NUM> may be controlled by a servo motor.

In addition, it can be seen that the induction heating device <NUM> includes an induction heating device support <NUM>, a columnar induction heating coil <NUM> with a hollow cavity, a temperature measuring element <NUM>, a compaction disk <NUM>, a distance measuring element <NUM>, a compacting force adjusting element <NUM> and a fixing rod <NUM>. The induction heating coil <NUM> and the temperature measuring element <NUM> are placed on the induction heating device support <NUM>, and the induction heating coil <NUM> carries out induction heating on the silicon steel plates <NUM> at an intermediate frequency of <NUM>-<NUM>. The temperature measuring element <NUM> is used to measure the temperature of the silicon steel plates <NUM>, and is arranged at a middle part of the induction heating coil <NUM>. In some embodiments, the temperature measuring element <NUM> may be an infrared temperature measuring element. The induction heating coil <NUM> and the temperature measuring element <NUM> are connected with the control device to control an induction heating process through the control device. The distance measuring element <NUM> is arranged above the induction heating coil <NUM>, and is connected with the compacting force adjusting element <NUM> so as to be mounted to the induction heating device support <NUM> through the compacting force adjusting element <NUM>. In addition, the distance measuring element <NUM> is connected with the control device and the distance measuring element <NUM> detects a distance between the distance measuring element and silicon steel plates <NUM> inside a stacking mold <NUM>, and transmits the same to the control device; and based on a signal transmitted by the distance measuring element <NUM>, the control device controls a distance that the loading and unloading device <NUM> conveys the stacking mold <NUM> in a vertical direction, and controls a distance that the compaction disk <NUM> moves in the vertical direction. The compacting force adjusting element <NUM> is arranged above the induction heating coil <NUM>, and is connected with the fixing rod <NUM>, so that the compacting force adjusting element <NUM> is mounted to the induction heating device support <NUM> through the fixing rod <NUM>, and the compacting force adjusting element <NUM> is connected with the control device. The compaction disk <NUM> is connected with the compacting force adjusting element <NUM>, and based on the control of the control device, under the adjustment of the compacting force adjusting element <NUM>, the compaction disk <NUM> moves vertically downward and applies a pressure to the silicon steel plates <NUM> inside the stacking mold <NUM>, or moves vertically upward to release the silicon steel plates <NUM>. In some embodiments, the compaction disk <NUM> may be made of a nonmetal material.

In addition, the loading and unloading device <NUM> includes a support <NUM>, a vertical displacement adjusting element <NUM>, a base plate <NUM>, a horizontal movable plate <NUM> and a stacking mold seat <NUM>. The vertical displacement adjusting element <NUM> is arranged on the support <NUM> and is connected with the control device, so that the loading and unloading device <NUM> is capable of conveying the stacking mold <NUM> in the vertical direction into the hollow cavity of the induction heating device <NUM> or moving the stacking mold out of the hollow cavity after the induction heating is completed. The base plate <NUM> is connected with the vertical displacement adjusting element <NUM> and driven by the vertical displacement adjusting element <NUM> to move in the vertical direction. The horizontal movable plate <NUM> is arranged on the base plate <NUM>, and is connected with the control device. The horizontal movable plate <NUM> is configured to be slidable in the horizontal direction relative to the base plate <NUM>, so that the loading and unloading device <NUM> can convey the stacking mold <NUM> in the horizontal direction to a position directly below the induction heating coil <NUM>. The stacking mold seat <NUM> is arranged on the horizontal movable plate <NUM>, for placing the stacking mold <NUM>, and is made of a nonmetal material in some embodiments. The stacking mold seat <NUM> is provided with a pressure sensor (not shown in the figure) to detect a pressure on the stacking mold seat <NUM> in real time, and the pressure sensor is connected with the control device, so that the control device controls a compaction degree of the silicon steel <NUM> based on a pressure value transmitted by the pressure sensor.

<FIG> is a structural diagram of the loading and unloading device in a loading initial state in some embodiments, in the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention. <FIG> is a structural diagram of the loading and unloading device in a loading completed state in some embodiments, in the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention. <FIG> is a structural diagram of the induction heating system for rapid curing of a silicon steel core with a self-adhesive coating of the present invention in a loading initial state in some embodiments.

Referring to <FIG>, <FIG>, <FIG>, <FIG> and <FIG>, in some embodiments, a process of induction heating on silicon steel plates stacked inside a stacking mold by using the induction heating system of the present invention may be as follows:.

Rapid induction heating and self-adhesive curing of the silicon steel plates <NUM> are accomplished by the above-mentioned steps, and the conveying roller table <NUM> continues operation, and the next round of treatment on silicon steel plates may be carried out by repeating the above-mentioned steps.

The stack of silicon steel plates <NUM> used in this embodiment has an outer diameter of Φ120 mm, an inner diameter of Φ40 mm, and a stack height of <NUM>. A compacting force in the direction of the stack height is set to <NUM>-<NUM> KN. The stack of silicon steel plates <NUM> enters the induction heating coil <NUM> to be heated, with a frequency of <NUM>, for <NUM> minutes to reach <NUM> , and is then cooled to room temperature.

An adhering fastening force test is performed on the stack of silicon steel plates by using a tension gauge. During the test, the silicon steel plate stack has one end face fixed to a test platform by a double-sided strong adhesive tape, and the other end face adhered to a tensile test end, which is connected with the tensile gauge, to stretch outward by means of a mechanical structure. During testing of the cured silicon steel plate core prepared by the technical solution of Embodiment <NUM>, the tension gauge exceeds its range, maximally displaying <NUM> kgf, but the stack of silicon steel plates is still not pulled apart, which proves that the core prepared by the technical solution of the present invention has a good adhering effect.

By using a same testing method, adhesive forces of a riveted stack and a welded stack are tested for comparison. A riveted core is uniformly distributed with <NUM> riveting points, and the stacked core of silicon steel plates is pulled apart under a pulling force of <NUM> kgf. A welded core is circumferentially uniformly distributed with <NUM> welding seams, and the stacked core is pulled apart under the action of <NUM> kgf.

Claim 1:
An induction heating system for a silicon steel core with a self-adhesive coating, comprising:
a conveying roller table (<NUM>), with a plurality of stacking molds (<NUM>) being conveyed thereon, the stacking molds (<NUM>) being used for placing stacked silicon steel plates (<NUM>) therein;
an induction heating device (<NUM>), which comprises a columnar induction heating coil (<NUM>) with a hollow cavity, wherein the induction heating coil (<NUM>) is arranged to carry out induction heating on a silicon steel plate (<NUM>) at a medium frequency of <NUM>-<NUM>, and a temperature measuring element (<NUM>) for measuring the temperature of the silicon steel plates (<NUM>);
a feeding and discharging device (<NUM>), which conveys the stacking mold (<NUM>) in a horizontal direction;
a loading and unloading device (<NUM>), which is configured to convey the stacking mold (<NUM>) in the horizontal direction to a position directly below the induction heating coil (<NUM>), and convey the stacking mold (<NUM>) in a vertical direction into the hollow cavity of the induction heating device (<NUM>) or moving the stacking mold (<NUM>) out of the hollow cavity after completing the induction heating; and
a control device, which is connected with the conveying roller table (<NUM>), the feeding and discharging device (<NUM>) and the loading and unloading device (<NUM>), respectively, to control respective operations thereof, wherein the control device is also connected with the induction heating coil (<NUM>) and the temperature measuring element (<NUM>) to control an induction heating process.