JP2013005553A - Method of heating stator by induction heating, and heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a method of heating a stator by induction heating which achieves satisfactory efficiency of induction heating and satisfactory operational efficiency of set-up of an induction coil for heating during manufacturing of a wide variety of stators; and a heating apparatus.SOLUTION: When varnish applied to the vicinity of a coil wound around a stator of an electrically powered machine is cured by performing induction heating of the stator, an induction heating part covers closely the entire outer periphery of the stator. A winding width is adjusted to such an extent that it substantially coincides with a thickness of a stator stack thickness. An induction heating coil is wound and disposed so that an induction heating current flowing through the coil in the induction heating part becomes one-way. The induction heating current is supplied to the induction heating coil, and the stator is heated while being rotated.

Description

  The present invention relates to an electric wire coil wound around a stator of an electric motor (motor), an electric generator (generator), or an electric machine having both functions (hereinafter referred to as “electric machine” including claims). Further, the present invention relates to a technical field relating to preheating for removing moisture from the stator core and annealing treatment, and heating for curing the varnish after application of the varnish (hereinafter referred to as “main heating”).

  As a heating method that efficiently performs preheating and main heating of the stator of the electric machine with as little energy as possible, there is a method of induction heating the stator. This method has been widely used for preheating conventionally, but has not been applied to the main heating. In the preheating, as described in the previous section, since heating for a short time was sufficient at a temperature slightly above 100 ° C. where water removal and the like can be performed, the preheating could be performed without any problems. However, this heating is a so-called indirect heating method that conducts heat generated when the stator is induction-heated to the wire coil, so the stator surface is first heated to a high temperature and the heat is protected outside the wire coil. It is necessary to transfer heat to the electric wire coil through the insulating material, and to maintain this for a relatively long time until the varnish curing reaction is completed.

  Moreover, since the temperature at which the varnish is cured is generally higher than the temperature at which moisture can be removed, in order to heat the varnish to a temperature suitable for the curing temperature of the varnish applied to the electric wire coil, as a result, an indirect heating part The heating level at the time of induction heating to the stator must be increased. For this reason, there is a concern that the varnish's volatile components are foamed due to rapid heating due to induction heating and the volatile matter of the varnish is foamed and cannot be completely removed, resulting in curing in the form of bubbles. is there. In addition, there is a problem of deterioration due to the heat effect on the insulation covering the outside of the wire coil, and furthermore, when there are many types of stators for electric machines, it becomes a dedicated facility and is not easy to use. It was not put into practical use.

  Further, as a recent problem, because of the VOC regulation of varnish (suppression of release of varnish volatile components into the atmosphere), the solvent component contained in the varnish must be suppressed, and in this case, the viscosity of the varnish increases. There is a problem that it is difficult for the varnish to penetrate into the slot portion in which the electric wire coil inside the stator is inserted.

  Furthermore, if the stator is subjected to main heating by induction heating with the varnish applied, the applied varnish will hang down on the induction heating coil for induction heating, and it may accumulate and stick to the surrounding mechanism. Therefore, it was difficult to put it to practical use as mass production equipment. As a solution, a method of moving the heating coil (for example, Patent Document 1), an induction heating coil having a semicircular shape only on the upper side, or a cavity on the lower side (for example, Patent Document 2, Patent Document 3), etc. Measures were taken.

JP 2008-92733 A JP 2009-283439 A JP 2010-262828 A

  However, the above-mentioned method of Patent Document 1 causes complicated facilities, and the methods of Patent Document 2 and Patent Document 3 use a semicircular special induction heating coil that covers only the upper side of the stator. This special induction heating coil has a different inductance from that of a normal coil that turns the outer periphery of the object to be heated multiple times, so it is very difficult to match the specified inductance of a general induction heating power supply. is there. For this reason, in order to eliminate the imbalance of the inductance matching, a matching transformer (a transformer for adjusting the inductance to the specified value of the induction power source) is required separately from the induction heating unit. In this case, a loss occurs in the matching transformer and heat is generated, so that the efficiency of induction heating is deteriorated, resulting in a problem that energy efficiency is deteriorated.

  Further, the shape of the stator varies depending on the output of the electric machine. With regard to the outer diameter of the stator, for example, in consideration of the convenience of the user who uses the motor, the mounting dimensions are standardized by JIS and the like, and the types of outer diameters are standardized accordingly. However, since the number of types of motor output as required cannot be increased only with the outer diameter, many methods are adopted in which the outer diameter is made constant and adjusted in the longitudinal direction (hereinafter referred to as stacking thickness). Very many.

  However, in the equipment of the induction heating method, the inductance is matched to each stator according to the gap between the induction heating coil and the stator and the width and number of turns of the induction heating coil according to the stator stacking thickness. The greater the number of child types, the greater the number of induction heating coil types for induction heating. In addition, when producing various types of stators, there is a problem in that the preheating and the change of the induction heating coil for the main heating frequently occur.

  Also, if the width of the induction heating coil is larger than the stack thickness of the stator, induction heating by the coil that protrudes from both ends of the stator is concentrated and heated at both ends of the stator. There is a problem that it is not heated uniformly.

  The present invention relates to a method for induction heating of the surface of a stator, and prevents varnish from dripping and adhering to the induction heating coil during the main heating, and even a varnish having a high viscosity conforming to VOC regulations is sufficient for a stator slot. Can be filled with varnish, and energy efficiency can be improved compared to the conventional method.

  That is, an object of the present invention is to provide a method for heating a stator by induction heating and a heating apparatus that are efficient in induction heating and have high work efficiency in changing the induction coil for heating when producing various types of stators. Is to provide.

The present invention is a method for heating a stator in which a stator of an electric machine is induction-heated to cure a varnish applied in the vicinity of a coil wound around the stator,
The induction heating portion covers the entire outer periphery of the stator close to each other, and the winding width is adjusted so as to substantially match the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is in one direction. Arrange the induction heating coil so that
An induction heating current is supplied to the induction heating coil, and the stator is heated while rotating.

  Further, in the method of heating a stator by induction heating described above, the induction heating portion is adapted to the coil width of the induction heating coil according to the difference in stator stacking thickness, and the energization portion is adjusted to the stator stacking width. Switching is performed by a switching circuit.

In the present invention, a varnish applied in the vicinity of a coil wound around a stator of an electric machine is fixed in order to harden the stator by a temperature profile including preheating, cooling, varnish application, temperature increase, and temperature holding. A stator heating method for heating a child,
The induction heating portion covers the entire outer periphery of the stator close to each other, and the winding width is adjusted so as to substantially match the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is in one direction. Arrange the induction heating coil so that
The temperature profile includes a varnish semi-curing step after varnish application, and in the preheating, temperature elevation, and temperature holding, the induction heating current is supplied to the induction heating coil and the stator is heated while rotating. To do.

  Further, in the method of heating a stator by induction heating described above, the induction heating portion is adapted to the coil width of the induction heating coil according to the difference in stator stacking thickness, and the energization portion is adjusted to the stator stacking width. It is characterized by switching.

  Further, in the method for heating a stator by induction heating described above, the varnish is applied while rotating the stator, and the rotation is maintained until the varnish is semi-cured even after the varnish is applied.

The present invention is a heating device for a stator that cures a varnish adhering to the vicinity of a coil wound around the stator by induction heating the stator of an electric machine,
A stator chuck jig for holding the stator while rotating;
A pair of coil end atmosphere heat insulation covers disposed at both ends of the stator held by the stator chuck jig;
Covers the entire outer periphery of the stator held by the stator chuck jig, has a winding width that approximately matches the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is uniform. An induction heating coil wound around the entire circumference of the stator so as to be oriented,
The stator is heated by supplying an induction heating current to the induction heating coil.

  Further, in the stator heating device described above, further, a varnish sagging receptacle is provided between the stator and the induction heating coil held by the stator chuck jig, over the entire circumference around the stator, It is provided.

  In the stator heating apparatus described above, a heat insulating material is further provided between the varnish sagging receptacle and the induction heating coil.

  Further, in the stator heating device described above, the induction heating coil circuit constituting the induction heating coil is configured by a plurality of circuits corresponding to the stack thickness dimension of the stator, and the induction heating coil according to the stack thickness dimension. The circuit is electrically switched to supply an induction heating current.

  In the stator heating device described above, the coil end atmosphere heat insulation cover is provided, and varnish attached to a material such as a string or a tube used for the coil end can be cured.

  In the stator heating device described above, at least one of the coil end atmosphere heat insulating covers is movable with respect to the stator held by the stator chuck jig. .

  In the present invention, in the method of heating a stator by induction heating described above, the center surface temperature of the stator and the temperature in the central portion of the slot are substantially set to the insulating material heat resistance temperature in maintaining the temperature profile. In addition, it is preferable that the temperature of the coil end of the stator is a varnish curing temperature lower than the heat resistance temperature of the insulating material, or the application of the varnish from the gradient of the temperature rise of the stator in the preheating of the temperature profile. It is preferable to lower the slope of the temperature rise in the subsequent temperature increase.

  In the present invention, in the stator heating device, after the preliminary heating, the stator is rotated at a high temperature that does not affect the temperature of the stator by providing some cooling and soaking time and the temperature of the stator is not affected by the varnish firing. The application of the varnish is started while maintaining the rotation until the varnish is semi-cured even after the application of the varnish. As a result, the varnish becomes a gel and almost no varnish droops. In addition, from the viewpoint of facility maintenance and maintenance, the inside of the induction coil is covered with a heat-resistant plastic film or the like, and some dripping is received with this. In addition, this film is regularly exchanged or cleaned.

  In addition, even if the outer diameter of the stator is standardized, if there are many types in the stacking direction, the outer diameter of the induction heating coil is fixed to accommodate the production of various types of stators in small quantities. An induction heating coil in which the winding width of the heating induction coil is matched to the stacking thickness is used. However, since this increases the types of induction heating coils, each induction heating coil with the same outer diameter is provided with a different induction heating coil circuit for each stacking thickness, and this is switched electrically. In this way, an induction heating coil is devised so that it can be handled only by this electrical circuit switching by using one induction heating coil for various types of stators. Further, in the stator heating apparatus described above, a coil end atmosphere heat insulation cover is provided, and a coil end atmosphere heat insulation cover is provided as a countermeasure against the varnish adhering to the string for fixing the coil end from being hardened. Furthermore, it is preferable that at least one of the coil end atmosphere heat retaining covers is movable with respect to the stator held by the stator chuck jig.

  According to the present invention, the induction heating coil that winds the entire circumference of the stator in one direction has good induction heating efficiency, and it is possible to significantly reduce energy. Further, it is not necessary to replace the heating induction coil according to the thickness of the stator, and the working efficiency is improved.

  In addition, since it can be controlled to input energy only when necessary, the conventional drying furnace method can greatly reduce energy compared to the state where energy must be constantly input even when empty such as waiting for work. become. Further, at this time, the viscosity of the varnish in the central portion in the slot can be lowered from the coil end portion by making a temperature difference so that the central portion in the slot is slightly higher than the coil end portion. For this reason, there is an advantage that the varnish can sufficiently penetrate into the slot by capillary action. As a result, even in the case of a varnish having a high viscosity corresponding to the VOC regulations, there is a feature that the varnish can be filled more fully in the slot than before.

It is a figure which shows the structure of the heating apparatus of the stator by the induction heating which becomes Example 1 of this invention. It is a figure which shows the structure of the heating apparatus of the stator by the induction heating which becomes Example 2 of this invention. It is a figure at the time of heating a stator with small stacking thickness only by the induction heating coil corresponding to the maximum stacking thickness, and the induction heating coil corresponding to the stacking thickness of many kinds. It is the circuit diagram of the induction heating coil corresponding to the various thickness of the induction heating coil of this invention, and is the figure which combined the induction heating coil on the single side | surface reference | standard. It is the circuit diagram of the induction heating coil corresponding to the lamination | stacking thickness of many kinds of the induction heating coil of this invention, and is the figure which combined the induction heating coil on the basis of the center of a stator. It is a figure which shows the temperature profile at the time of induction heating of the stator by said Example. It is a figure which shows the varnish filling state in the slot part of the stator obtained by said Example. It is a figure which shows the varnish filling state in the slot part of the stator obtained by said Example.

  Embodiments will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a stator heating device by induction heating according to Embodiment 1 of the present invention.

  In FIG. 1A, reference numeral 8 denotes a coil end atmosphere heat insulation cover provided at both ends of the stator where varnish is applied in the vicinity of the coil wound around the stator, and reference numeral 7 denotes an induction heating coil. Is shown. Further, around the inner periphery of the induction heating coil 7, a alligator drop receiver 11 is provided. FIG. 1 (B) shows an AA ′ cross section in FIG. 1 (A). The outer shape of the stator 1 having a substantially cylindrical shape is formed with a plurality of slot portions 4 on its inner peripheral surface side, The electric wire coil 3 is wound around the inside and further, both ends (coil end portion 6) of the stator. In addition, a stator chuck jig 9 is inserted into the stator 1 through one coil end atmosphere heat insulating cover 8 to fix the stator.

  Further, an induction coil 7 for induction heating of a portion such as the stator that needs to be heated is approximately equal in width to the width of the stator, and is wound in one direction around the entire circumference of the stator 1. Has been. In the figure, reference numeral T16 indicates a measurement point of the stator center surface temperature, T17 indicates a measurement point of the slot inner center temperature, and T18 indicates a measurement point of the coil end temperature.

  FIG. 1C shows an example of the stator 2 in which the stack thickness 12 of the substantially cylindrical stator 1 is longer than that in FIG. In this case, the induction heating coil 7 is wound around the portion exceeding the stack thickness of the stator 1 by extending the induction heating coil 7 in the same winding direction at substantially the same pitch as the induction heating coil of FIG. The width of the stator 2 is adjusted to the width. Finally, an induction heating coil in which a coil having a length matching the stacking width 12 of the long stator 2 in FIG. 1C is wound around the entire circumference of the stator 2 in one direction. 7 At this time, as the induction heating coil 7, the coil portion shown in FIG. 1B and the extended coil portion shown in FIG. An induction heating coil 7 having a size substantially matched to the width 12 of the child 2 is formed. In this case, it is desirable that the winding pitch of the induction heating coil 7 be approximately the same in FIGS. 1B and 1C.

  In FIG. 1D, the stator 1 is indicated by a broken line, and in particular, the circuit of the induction heating coil 7 (the winding (wiring) state of the induction heating coil) is shown. As is apparent from this figure, the induction heating coil 7 is configured to be wound a plurality of times in the same direction so as to cover the stator, and covers the entire circumference of the stator 1 (or 2). It is attached. Further, the induction heating coil 7 is divided into circuits each having a length substantially matched to the stacking thickness 12 according to the type of the stacking thickness 12 of the stator 1 and, if necessary, a connection terminal 13 (switching circuit). The circuit is connected, and the region where the induction heating coil can be electrically energized is devised so as to be approximately matched to the width of the stator. Further, when curing the varnish, although not shown here, for example, the stator 1 is rotated by rotating the stator chuck jig 9 with a motor or the like.

  Further, as apparent from the above figure, when the varnish applied (applied by dropping) in the vicinity of the coil end portion 6 is infiltrated and cured, the induction heating coil 7 disposed close to the outside of the stator 1 is used. Particularly, in the induction heating portion of the induction heating coil 7, in order to allow the heating current to flow in one direction in the coil wound in the same direction a plurality of times (see the arrow in FIG. 1D), these coils are used. Are arranged along the outer peripheral surface of the stator 1. As a more specific example, the current flowing through the induction heating coil 7 is set to flow only in a direction perpendicular to the rotation axis direction of the substantially cylindrical stator 1. However, the flow of the induction heating current may be in one direction, and the direction is not defined.

  According to the configuration of the heating device described above, the stator 1 can be heated relatively uniformly. In particular, in the case of the stator 1 or the like in which the surface of the stator 1 is integrally fixed by welding or the like after laminating steel plates to form a stator shape, a lot of induction heating is generated in the welded portion, The surface of the stator 1 is rapidly heated, resulting in a large temperature difference from the coil end portion 6. Therefore, as described above, it is important to wind the entire circumference of the stator 1 with the current flow in one direction.

  Moreover, since the electric wire coil 3 of the coil end part 6 is scattered or swells before the varnish is hardened, the coil end part 6 is tied with a string 10 or the like and fixed in advance, or the coil end part 6 serving as an electricity entrance / exit of the electric machine. The lead wire 5 is fixed by a lead wire protective tube, but these are not metals, so their thermal conductivity is poor, and it is difficult to sufficiently transfer heat only by the heat conduction of the induction heating coil 6. Therefore, the varnish adhering to this part is hard to harden. In particular, when the outside air temperature is low, heat radiation from the coil end portion 6 is intense, and it becomes more difficult to cure the string 10 and the like in this portion. As a countermeasure against this, the ambient temperature cover 8 for covering the coil end portion 6 is used to stabilize the ambient temperature around the coil end. This makes it possible to provide a function of completely curing the cord 10 and the varnish of the lead protection tube at the base of the lead side 5, which is also a great feature.

  As described above, the varnish application method is a method in which the varnish is dropped onto the coil end portions 5 on both sides while rotating the stator 1 in the circumferential direction and in one direction while holding the stator 1 almost horizontally. The methods relating to rotation, the dropping nozzle and the dropping position are omitted because they are already known cases.

  FIG. 2 shows the configuration of the heating apparatus according to the second embodiment of the present invention. Also in this embodiment, the same constituent elements as those in the above embodiment are indicated by the same reference numerals as above.

  The second embodiment is almost the same as the first embodiment, except that the generated heat generated when the stator is heated between the varnish sagging tray 11 and the induction heating coil 7 is different from that of the induction heating coil 7. The difference is that the heat insulation material 14 and the heat insulation material 15 are inserted and devised so as not to escape to the outside and the induction heating coil 7 is not deteriorated by the influence of the generated heat. In addition, in the case of Example 2, the induction heating coil 7 was generated in the induction heating coil 7, although the countermeasure such as air cooling from the outside so as not to deteriorate with the generated heat of the stator is also a common sense technique. By confining heat, it is more effective in terms of energy saving.

  In addition, as shown in Example 2, when the induction heating coil 7 is not wound with a width substantially the same as the width of the stator and is intended to be shared by the induction heating coil 7 having the same width regardless of the stacking thickness. In particular, when a stator having a small stacking thickness is heated by the induction heating coil 7 having a long winding width, the induction heating tends to cause electromagnetic induction at both ends of the cylindrical portion of the substantially cylindrical stator. However, it generates abnormal heat, making it difficult to heat and control the stator relatively evenly. In particular, when using a member having a limit of heat resistance such as a temperature necessary for curing the varnish and an insulating material, if the induction heating coil 7 is used in combination with this method, the temperature control becomes difficult. It is very effective to adjust the width of the coil and the width of the induction heating coil 7 to substantially the same level for more stable induction heating.

  FIG. 3 is a diagram specifically explaining the contents described above. FIG. 3A shows a circuit diagram in which the induction heating coil 7 matched to the maximum stacking width is also used as a stator having the minimum stacking width. An induction heating coil 7 that is wound around the induction heating coil 7 with the same width as the induction heating coil 7 that matches the stacking width of the large stacking thickness 3 is a stator having a small stacking width such as a small stacking thickness 1. When the induction heating coil 7 for the large stacking thickness 3 is used for induction heating, as shown in FIG. It becomes a state of high heating. This is because the electromagnetic induction energy in the portion where the induction heating coil 7 is overhanged is more likely to concentrate on the end of the stator than in the case where the stacking thickness is smaller than 1 and the corners are particularly hot due to the absence of heat escape. turn into. In this case, it is very difficult to control the stator that is required to uniformly cure the varnish to uniformly heat the varnish. For this reason, in each Example of this invention, it is supposed that it heats by combining the winding width of the induction heating coil 7 with the stacking thickness of a stator like the stacking thickness 3.

  With reference to FIG. 4, the configuration of the induction heating coil portion 7 according to the first and second embodiments of the present invention will be described in an easily understandable manner.

  If the outer diameter of the stator is within the range of the relative distance from the induction heating material specified by the induction heating power source (hereinafter referred to as a gap with the stator), the outer diameter is somewhat Since the outer diameter of the induction heating coil can be shared even if there is a difference, the stator having an outer shape that falls within this shareable range is shared by the same induction heating coil 7 diameter. And in order to solve the problem shown in the third embodiment, for example, a plurality of stacking widths of the respective stators according to the widths of the stators having a small stacking thickness 1, a stacking thickness of 2, and a stacking thickness of 3 are used. The induction heating coil 7 is constituted by the coil circuit of the above, and it is devised so that even a variety of stators with different thicknesses can be handled with one induction coil.

  At this time, one end portion of the induction heating coil 7 is used as a reference surface 8, and the reference surface 8 is wound around the base point, and an induction heating circuit for extending the stacking thickness is extended in the stacking longitudinal direction, and It is assumed that a necessary number of circuits are configured. Then, the induction heating coil circuit is switched to energize in accordance with the stacking thickness. Thereby, compared with Example 5 mentioned later, the stator of various thickness can be heated with simple equipment. In addition, as for the winding pitch of the induction heating coil 7, it is desirable to wind in the same direction at the same pitch.

  A case where the induction heating coil 7 is formed with reference to the center of the stator 1 will be described with reference to FIG. As in Example 3, the outer diameter of the stator may be within a range of a relative distance (hereinafter referred to as a gap with the stator) relative to the induction heating material specified by the induction heating power source. For example, since the outer diameter of the induction coil can be shared even if there is a slight difference in the outer diameter, a stator having an outer shape that falls within this shareable range is shared by the same diameter of the induction heating coil 7.

  Further, for example, the induction heating coil 7 is wound around one induction heating coil 7 in accordance with the stacking width of each stator with reference to the center of the stator having a small stack thickness 1 and a large stack thickness 3. Thus, the induction heating coil is shared by one. In this case, for the induction heating circuit, the induction heating coil 7 circuit is configured individually for each stacking longitudinal direction, and if necessary, an induction heating coil circuit for a stator having a width suitable for the stator 1 is provided. The circuit is configured by electrical switching. In addition, as for the winding pitch of the induction heating coil 7, it is desirable to wind in the same direction at the same pitch.

  In the case of this method, as the number of types of stacking increases, the amount of the lap winding member of the induction heating coil at the center of the stator increases, and in some cases, the induction heating coil 7 is physically located at the center. It may also occur when it cannot be rolled up. In this case, a plurality of induction heating coils 7 are individually created for each stack thickness of the stator, and the stator is selected and set on the induction heating coil 7 that matches the width of the stator, and induction heating or the like is performed. Therefore, in the case of troubles such as setup change and an automatic machine, there is a problem that the equipment configuration becomes complicated.

  Next, FIG. 6 shows the details of the method of heating the stator described in the above embodiment, particularly the temperature profile thereof.

  FIG. 6 shows a series of steps from preheating (preheating) S1 (process) to the stator 1, cooling S2, varnish application S3, varnish semi-curing S4, temperature rising S5, and temperature holding S6. A temperature profile is shown, with the horizontal axis representing time and the vertical axis representing temperature. That is, it is a temperature profile model including preheating S1, cooling S2, varnish application S3, varnish semi-curing S4, temperature rise S5, temperature holding S6.

  The characteristics of this temperature profile are shown below. First, after preheating (preheating) S1 for moisture removal and annealing, the stator 1 is cooled S2. Varnish application S3 is started while rotating the stator in the middle of cooling S2. The starting temperature of the varnish application S3 is preferably started at a temperature as high as possible without causing firing even when the varnish contacts a high temperature stator. After completion of the varnish application S3, the varnish is left for a certain period of time while rotating the stator until the varnish is semi-cured. When applying the varnish, usually, such a standing time is usually provided to remove the excessively adhered varnish. At this time, by starting the varnish application at the upper limit allowed by the varnish characteristics as described above, the varnish is semi-cured by the residual heat of the stator while it is left, so that the varnish in the subsequent process is Sagging can be suppressed considerably.

  Next, in order to cure the applied varnish, a temperature increase S5 is started. In order to prevent rapid heating, the temperature rise S5 is such that the foaming phenomenon of the volatile solvent contained in the varnish does not occur by using the induction heating coil 7 as shown in any of the first to third embodiments. A gentle curve is necessary. That is, the slope of the temperature rise at the temperature rise S5 is made smaller than the slope of the temperature rise at the preheating (preheating) S1. Further, when the temperature rise S5 reaches a temperature suitable for varnish curing determined for the varnish, the temperature and time are maintained under the conditions determined for the varnish in the temperature retention S6 in order to maintain this temperature.

  For example, at the timing of this temperature holding S6, the coil end atmosphere heat insulating cover 8 is slid (moved) sideways (see the white arrow in FIGS. 1 to 2), and the temperature around the coil end portion 6 is adjusted. By maintaining the temperature suitable for varnish curing, the varnish adhering to the string 10 of the electric wire coil 3 or the protective tube on the lead side 5 can also be cured.

  Further, in this temperature profile model, when the surface of the stator 1 is induction-heated, the temperature T17 (one-dot broken line) in the central portion of the slot 4 and the temperature T18 of the coil end portion 6 (in accordance with the order of heat transfer by indirect heating) A temperature difference ΔT occurs in the solid line). It is desirable that the temperature difference ΔT is slightly lower than the insulating material heat-resistant temperature Ti. This prevents deterioration of the insulating material and allows the varnish to sufficiently penetrate into the slot 4 by capillary action.

  Thereby, high-density filling of the varnish into the inside of the slot part 4 is attained. The insulation heat resistance temperature Ti is a temperature determined from the guaranteed operating time of the product set for the product (for example, the motor) and the temperature rise condition of the motor determined from the guaranteed load condition, and is determined from the comprehensive conditions of these product specifications. It is common to select an insulating material that can withstand the worst conditions.

  It should be noted that the timing at which the coil end atmosphere heat retaining cover 8 is slid laterally to seal the coil end portion 6 is preferably after the volatile matter of the varnish has completely evaporated.

  Further, FIG. 7 illustrates a stator manufactured by the above-described stator heating apparatus and method therefor. FIG. 7 (A) is an enlarged view showing a part of the steel plate of the stator 1, and FIG. 7 (B) is an enlarged view of the slot portion 4. As shown in these drawings, Inside the slot portion 4, there are provided a plurality of electric wire coils 3 housed in the insulating material 23 and the insulating material 24 provided therein and having a circular cross section.

  Originally, the portion to be filled with the varnish is indicated by the varnish 25, that is, the space other than the electric wire coil 3 surrounded by the insulating material 22 and the insulating material 23, and the slot portion of a part (steel plate) 26 of the stator 1 4, the gap between the insulating material 23 and the insulating material 24, and the slot portion 4, and it is most ideal that these openings can be completely filled with varnish. This is because, if all of these can be filled in close contact with the varnish 25 without generating air bubbles, the generated heat generated when the electric power for operating the electric machine is energized to the electric wire coil is generated. Can efficiently dissipate heat to the stator 1 side, and the electric coil 3 vibrates due to minute electromagnetic induction when the electric machine is repeatedly operated and stopped, and the electric wire coil 3 rubs and wears, resulting in poor insulation. This is because it can also be prevented.

  FIG. 7C is a state diagram when, for example, the size of the circular shape of the cross section of the electric wire coil 3 is reduced (that is, the wire diameter is reduced) and wound with an extra fine wire. However, as the filling degree of the electric wire coil 3 increases (the improvement in the electric wire coil filling rate), the gap between the varnishes 25 to be filled decreases. Even in this case, according to the method of heating the stator by induction heating and the heating device of the present embodiment, the varnish 25 is caused by the temperature difference between the temperature T18 of the coil end portion and the temperature T17 of the central portion inside the slot. However, the feature (effect) of being easier to penetrate into the slot portion 4 by capillary action is achieved.

  Further, FIG. 8 illustrates another example stator manufactured by the stator heating apparatus and the method therefor described in detail above. The example of FIG. 8 is a case where the stator has a shape of the electric wire coil 3 different from that of FIG. 7, and the cross section of the coil is a hexagonal shape. That is, the stator has a high space factor. In this embodiment, even in this case, the varnish can be easily penetrated by the effect of the capillary phenomenon.

  As described in detail above, according to the present embodiment, the following is provided.

  That is, first, (1) an induction heating system having an induction heating coil and a coil core that supports the induction heating coil, the coil core is wound around the circumference by the same coil core as the stator 1. Induction heating coil induction heating system.

  Next, as (2), in the above (1), the induction heating coil formed on the coil core is formed so that the winding pitch of the induction coil is substantially the same. It is.

  Further, as (3), in (1) or (2) above, a step of holding the stator while rotating until the varnish is semi-cured after varnish application S3 is provided, and the induction heating coil is fixed at the temperature rise S5. This is an induction heating system in which a varnish drooping receiver is provided between the children, and the varnish is prevented from directly adhering to the induction heating coil.

  In addition, as (4), in the induction heating system in which the object to be heated having the stator, the slot portion, the electric wire coil, and the coil end portion is induction heated by the induction heating member of (1) to (3) above, induction heating is performed. In the induction heating system, the coil winding is wound in one direction in the circumferential direction of the stator of the object to be heated.

  Further, (5) is an induction heating system in which a cover for receiving the varnish drooping is provided inside the induction heating coil so that the varnish does not adhere to the induction heating coil in (4).

  Moreover, as (6), the impregnation part which impregnates a to-be-heated material with a varnish, the preheating part which preheats a to-be-heated material before impregnation, or the hardening part which heat-hardens the varnish which impregnated the to-be-heated material after impregnation An electrical insulation processing apparatus having at least one of the induction heating apparatuses (1) to (5) as a heating means for an object to be heated in at least the preliminary heating section or the curing section. It is a processing system.

  Further, as (7), in (6) above, moisture is removed while raising the temperature in the preheating portion, varnish is impregnated while cooling in the impregnation portion, and the temperature is raised to a predetermined temperature and held in the curing portion. An electrical insulation system for curing a varnish.

  Further, (8) is an apparatus having an induction heating method and a hot air heating method in a heating device for curing a varnish applied or impregnated in a coil in a manufacturing process of an electric machine.

  Further, (9) is a heating apparatus having an exhaust system surrounding the electric machine for the purpose of exhausting volatile components from the varnish in the heating apparatuses (1) to (8).

  DESCRIPTION OF SYMBOLS 1 ... Stator, 2 ... Stator, 3 ... Electric wire coil, 4 ... Slot part, 5 ... Lead side, 6 ... Coil end part, 7 ... Induction heating coil, 8 ... Coil end atmosphere thermal insulation cover, 9 ... Stator chuck Jig, 10 ... string, 11 ... varnish sink, 13 ... switching circuit, 14, 15 ... heat insulating material, 23 ... insulating material, 24 ... insulating material, 25 ... varnish, 26 ... part of stator 1 (steel plate ).

Claims (11)

A method of heating a stator by induction heating in which a stator of an electric machine is induction-heated to cure a varnish applied in the vicinity of a coil wound around the stator,
The induction heating portion covers the entire outer periphery of the stator close to each other, and the winding width is adjusted so as to substantially match the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is in one direction. Arrange the induction heating coil so that
A method of heating a stator by induction heating, wherein an induction heating current is supplied to the induction heating coil, and the stator is heated while rotating. The method of heating a stator by induction heating according to claim 1,
Stator heating by induction heating, characterized in that the induction heating part switches the current-carrying part with a switching circuit according to the difference in stator stacking thickness and the coil width of the induction heating coil according to the stator stacking width. Method. The stator is heated in order to cure the varnish applied to the vicinity of the coil wound around the stator of the electric machine, according to a temperature profile including preheating, cooling, varnish application, temperature increase, and temperature holding. A method of heating a stator by induction heating,
The induction heating portion covers the entire outer periphery of the stator close to each other, and the winding width is adjusted so as to substantially match the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is in one direction. Arrange the induction heating coil so that
The temperature profile includes a varnish semi-curing step after varnish application, and in the preheating, temperature elevation, and temperature holding, the induction heating current is supplied to the induction heating coil and the stator is heated while rotating. To heat the stator by induction heating. The method of heating a stator by induction heating according to claim 3,
A method for heating a stator by induction heating, wherein the induction heating portion switches the energization portion in accordance with the coil width of the induction heating coil in accordance with the difference in the stack thickness of the stator, according to the stack thickness width of the stator.   The induction heating method according to claim 3, wherein the varnish is applied while rotating the stator, and the rotation is maintained until the varnish is semi-cured even after the varnish application. Stator heating method. A stator heating device that cures the varnish adhering to the vicinity of the coil wound around the stator by induction heating the stator of the electric machine,
A stator chuck jig for holding the stator while rotating;
A pair of coil end atmosphere heat insulation covers disposed at both ends of the stator held by the stator chuck jig;
Covers the entire outer periphery of the stator held by the stator chuck jig, has a winding width that approximately matches the thickness of the stator stack, and the induction heating current flowing through the coil in the induction heating portion is uniform. An induction heating coil wound around the entire circumference of the stator so as to be oriented,
A stator heating apparatus by induction heating, wherein the stator is heated by supplying an induction heating current to the induction heating coil.   The stator heating device by induction heating according to claim 6, further comprising a varnish sagging receiver between the stator held by the stator chuck jig and the induction heating coil, around the stator. A stator heating device by induction heating, characterized by being provided over the entire circumference.   The stator heating device by induction heating according to claim 7, further comprising a heat insulating material provided between the varnish sagging receptacle and the induction heating coil.   7. The stator heating apparatus by induction heating according to claim 6, wherein the induction heating coil circuit constituting the induction heating coil is configured by a plurality of circuits corresponding to the stack thickness dimension of the stator, and according to the stack thickness dimension. A stator heating apparatus, wherein an induction heating current is supplied by electrically switching a circuit of an induction heating coil.   The stator heating device by induction heating according to claim 6, wherein the coil end atmosphere heat insulation cover is provided, and varnish attached to a material such as a string or a tube used for the coil end can be cured. Stator heating device by induction heating.   7. The stator heating device by induction heating according to claim 6, wherein at least one of the coil end atmosphere heat insulation covers is movable with respect to the stator held by the stator chuck jig. Stator heating device by induction heating.

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