JP2015126625A - Method for annealing laminated core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten temperature averaging and heating time of a laminated core in annealing of the laminated core.SOLUTION: Disclosed is a method for annealing a laminated core 9 which has the laminated electromagnetic steel sheet 91 and in which a plurality of teeth 92 are formed in the inner peripheral side. Rod-like heaters 2 are arranged on the inner peripheral side of the laminated core 9, rod-like or plate-like heat transfer members 11 made of a material whose heat transfer coefficient is higher than that of the laminated core 9 are inserted between teeth 92 of the laminated core 9. The teeth 92 of the laminated core 9 and the heat transfer members 11 are heated by the heaters 2, and the teeth 92 of the laminated core 9 are heated even by the heat transfer member 11.

Description

  The present invention relates to a method for annealing a laminated core. More specifically, the present invention relates to a method for annealing a laminated core formed by laminating electromagnetic steel sheets and the like, and relates to an annealing method for removing strain and reducing iron loss.

  A general laminated core applied to an electric motor is formed by punching and laminating electromagnetic steel sheets into a predetermined shape and joining them by welding or caulking. By the way, a magnetic steel sheet may be distorted during punching. When distortion occurs in the electromagnetic steel sheet, the iron loss increases and the energy efficiency of the electric motor decreases. For this reason, after laminating | stacking and joining the punched electromagnetic steel plate, annealing may be implemented in order to remove distortion using an annealing apparatus. For this reason, for example, as described in Patent Documents 1 to 3, after the punched electromagnetic steel sheets are stacked and joined, annealing may be performed to remove strain.

International Publication No. 2013/111726 JP 2003-319587 A JP 2003-319618 A

As an example of a method of annealing a laminated core formed of an electromagnetic steel sheet, for example, heating to 750 ° C. or higher using a heating furnace, further heating for about 2 hours for soaking, and then gradually cooling The method is used. Thus, in annealing a laminated core, it is necessary to heat the laminated core for a long time. For this reason, annealing of the laminated core has a problem that productivity is low. Therefore, there is a demand for shortening the heating time in order to improve productivity. In order to shorten the heating time, for example, Patent Document 1 discloses a configuration in which a rod-shaped halogen heater is inserted into a laminated core and the laminated core is heated from the inner peripheral side (side on which teeth are formed). . In addition, Patent Literature 2 and Patent Literature 3 disclose a method of heating a tooth of a laminated core by inserting a heating wire such as a nichrome wire between teeth (slit).
However, these methods may cause uneven temperature in the axial direction of the laminated core. In particular, when a plurality of laminated cores are stacked and heated simultaneously, uneven temperature tends to occur. When the temperature deviation is increased, if the target temperature is set at the part where the temperature rises the fastest, the annealing effect may be lowered at the part where the temperature rise is slow. On the other hand, if the target temperature is set at a part where the temperature rises the fastest, the temperature at the part where the temperature rises fast becomes too high, and there is a risk of deformation.

  The present invention has been made in view of the above problems, and in annealing of a laminated core formed by laminating electromagnetic steel sheets, it is possible to shorten the heating time while preventing uneven temperature. An object is to provide an annealing apparatus and an annealing method.

  In order to solve the above-mentioned problem, the present invention is a method for annealing a laminated core having a laminated electromagnetic steel sheet and having a plurality of teeth formed on the inner circumference side, wherein the rod-shaped heater is disposed on the inner circumference side of the laminated core. And placing a rod-like or plate-like heat transfer member made of a material having a higher thermal conductivity than the laminated core between the teeth, and heating the teeth and the heat transfer member by the heater, The teeth are also heated by the heat transfer member.

  ADVANTAGE OF THE INVENTION According to this invention, in annealing of the laminated core comprised by laminating | stacking an electromagnetic steel plate, shortening of heating time can be aimed at, preventing uneven temperature.

FIG. 1 is a perspective view schematically showing an annealing method according to an embodiment of the present invention. FIG. 2 is an exploded perspective view schematically showing a configuration of a jig used in the annealing method according to the embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a state where the jig is attached to the laminated core, and is a view cut along a plane perpendicular to the axial direction of the laminated core. FIG. 4 is a cross-sectional view schematically showing a state where the jig is attached to the laminated core, and is a view cut along a plane parallel to the axial direction of the laminated core. FIG. 5A is a cross-sectional view showing a first example of the cross-sectional shape of the heat transfer member, and FIG. 5B is a cross-sectional view showing a second example of the cross-sectional shape of the heat transfer member. FIG. 6 is a cross-sectional view schematically showing an annealing method using a chamber. FIG. 7 is an external perspective view schematically showing a configuration example of a laminated core that is an object to be annealed.

Embodiments of the present invention will be described below in detail with reference to the drawings.
The annealing method according to the embodiment of the present invention is used for annealing a laminated core for an electric motor. Here, the structural example of the lamination | stacking core which is an annealing target object is demonstrated easily with reference to FIG. FIG. 7 is an external perspective view schematically showing a configuration example of the laminated core 9 that is an object to be annealed. The laminated core 9 is formed by laminating a plurality of electromagnetic steel plates 91 punched in an annular shape, and has a cylindrical configuration penetrating in the axial direction as a whole. A plurality of teeth 92 are formed on the inner peripheral side of the laminated core 9. The plurality of teeth 92 has a convex configuration, each protrudes toward the center side in the radial direction, and extends in the axial direction. The plurality of teeth 92 are formed so as to be arranged at predetermined intervals in the circumferential direction. For convenience of explanation, the gap between the teeth 92 is denoted as “slit 93”, the surface facing the radial center of the tooth 92 is denoted as “top surface 921 of the tooth 92”, and the surface facing the circumferential direction of the tooth 92 (A surface facing the tooth 92 adjacent in the circumferential direction) is referred to as a “side surface 922 of the tooth 92”.

FIG. 1 is a perspective view schematically showing an annealing method according to an embodiment of the present invention.
As shown in FIG. 1, in the annealing method according to the embodiment of the present invention, one or a plurality of rod-shaped heaters 2 (hereinafter simply referred to as “heater 2”) and a jig 1 for soaking (hereinafter referred to as “heat equalizing”). Simply referred to as “jig 1”). Then, the jig 1 is attached to the laminated core 9, and one or more heaters 2 are inserted into the inner peripheral side of the laminated core 9 to heat the laminated core 9 from the inner peripheral side. In the embodiment of the present invention, the heater 2 is inserted into the inner peripheral side of the laminated core 9, and the jig 1 is attached to the laminated core 9, so that the heating time is improved while the laminated core 9 is heated in the axial direction. To shorten. Further, the jig 1 prevents or suppresses the deformation of the laminated core 9. 1 shows a configuration in which four heaters 2 are used, the number of heaters 2 is not limited.

A rod-shaped halogen heater (also referred to as a halogen lamp heater) is applied to the heater 2. In particular, a rod-like halogen heater that emits near infrared rays (infrared rays having a wavelength band of 0.78 to 2.0 μm) or infrared rays including a near infrared wavelength band is suitable. The halogen heater has, for example, a configuration in which a tungsten filament is provided inside a cylindrical quartz glass tube and an inert gas and a halogen substance are enclosed. As the heater 2, various known halogen heaters can be applied. Therefore, description of the detailed configuration of the heater 2 is omitted.
In addition, the heater 2 has a heat generating portion (a portion that emits infrared rays excluding electrodes and the like) whose axial dimension is longer than the axial dimension of the laminated core 9. During annealing, the heater 2 is disposed such that the intermediate portion in the axial direction is accommodated on the inner peripheral side of the laminated core 9 and both end portions protrude from the end face 94 of the laminated core 9. When a plurality of laminated cores 9 are stacked and annealed at the same time, the heater 2 has a heat generating portion whose axial dimension is longer than the total axial dimension of the stacked laminated cores 9.

The jig 1 has a function of achieving uniform temperature in the axial direction of the laminated core 9 and a function of preventing or suppressing deformation of the laminated core 9. FIG. 2 is an exploded perspective view schematically showing the configuration of the jig 1. 3 and 4 are cross-sectional views schematically showing a state in which the jig 1 is attached to the laminated core 9. 3 is a cross-sectional view taken along a plane perpendicular to the axial direction of the laminated core 9, and FIG. 4 is a cross-sectional view taken along a plane parallel to the axial direction of the laminated core 9. In FIG. 4, the heater 2 is omitted.
As shown in FIGS. 2 to 4, the jig 1 includes a predetermined number of heat transfer members 11, a lid member 13, and a heat shield member 14. The predetermined number of heat transfer members 11, the lid member 13, and the heat shield member 14 are configured to be able to be coupled and separated.

  The heat transfer member 11 is formed in an elongated plate shape or rod shape that can be inserted into the slit 93 of the laminated core 9. The heat transfer member 11 is formed of a material having high thermal conductivity such as copper. In particular, it is formed of a material having a higher thermal conductivity than at least the material of the laminated core 9 (the magnetic steel sheet 91 in the present embodiment) that is an annealing target. A predetermined number (specifically, the same number as the slits 93) of the heat transfer members 11 is such that each heat transfer member 11 enters each slit 93 in a state where the jig 1 is attached to the laminated core 9. In addition, they are arranged in an annular shape at a predetermined interval in the circumferential direction. Further, the dimension of the heat transfer member 11 in the axial direction is longer than the dimension of the laminated core 9 in the axial direction. When a plurality of laminated cores 9 are stacked and annealed simultaneously, the axial dimension of the heat transfer member 11 is longer than the sum of the axial dimensions of the stacked laminated cores 9. For this reason, when the jig 1 is attached to the laminated core 9, the intermediate portion in the axial direction of the heat transfer member 11 is accommodated on the inner peripheral side of the laminated core 9, and both ends protrude from the end surface 94 of the laminated core 9.

The heat transfer members 11 are joined to each other by the connecting member 12 so as to maintain the above-described arrangement. For example, the connecting member 12 is formed in a cylindrical shape penetrating in the axial direction. Note that the inner diameter of the connecting member 12 is set to a diameter through which one or a plurality of heaters 2 can be inserted. The predetermined number of heat transfer members 11 are integrally joined by the connecting member 12 at the end in the axial direction. Moreover, in each figure, although the structure in which the predetermined number of heat-transfer members 11 are joined inside the radial direction is shown, the structure joined on the middle or outside in the radial direction may be used.
Note that the connecting member 12 is not provided in a portion located on the inner peripheral side of the laminated core 9 in a state where the jig 1 is attached to the laminated core 9. Therefore, even when the jig 1 is attached to the laminated core 9, the top surface 921 of the teeth 92 of the laminated core 9 is exposed without being covered by the connecting member 12 or the like (FIGS. 3 and 3). 4). For this reason, the infrared rays emitted from the heater 2 can be directly applied to the top surfaces 921 of the teeth 92.

Here, an example of a cross-sectional shape of the heat transfer member 11 will be described. FIG. 5A is a cross-sectional view showing a first example of the cross-sectional shape, and FIG. 5B is a cross-sectional view showing a second example of the cross-sectional shape.
The first example shown in FIG. 5A is an example in which the slit 93 is formed in substantially the same shape. As shown in FIG. 5A, when the cross-sectional shape of the slit 93 is a substantially quadrilateral, the cross-sectional shape of the heat transfer member 11 is also formed into a substantially quadrilateral that follows the shape of the slit 93. According to the first example, when the heat transfer member 11 is inserted into the slit 93, a surface facing the circumferential direction of the heat transfer member 11 (hereinafter referred to as “circumferential side surface 112 of the heat transfer member 11”). ) And the side surface 922 of the tooth 92 are close to each other and face or contact each other in a substantially parallel state. With such a configuration, the infrared rays emitted from the heater 2 are applied to the surface of the heat transfer member 11 facing the center in the radial direction (hereinafter referred to as “the inner surface 111 of the heat transfer member 11”). And when infrared rays are irradiated from the heater 2 to the inner surface 111 of the heat transfer member 11, the heat transfer member 11 is heated and the temperature rises, and from the circumferential side surface 112 of the heat transfer member 11 to the side surface 922 of the tooth 92, Heat is transmitted by conduction and radiation. Thereby, the teeth 92 of the laminated core 9 are heated.

A second example of the heat transfer member 11 shown in FIG. 5B is an example in which the heat transfer member 11 is formed in a substantially isosceles triangle that is tapered toward the center in the radial direction. And the surface corresponding to the base of the isosceles triangle faces the inner peripheral surface between the teeth 92 of the laminated core 9, and the remaining two surfaces (hereinafter referred to as “the inclined surface 113 of the heat transfer member 11”). Are opposed to the side surface 922 of the tooth 92 of the laminated core 9 in an inclined state. For this reason, the space | interval of the inclined surface 113 of the heat-transfer member 11 and the side surface 922 of the tooth | gear 92 becomes large as it goes to a radial direction center side.
According to the second example, the infrared rays emitted from the heater 2 are applied to the inclined surface 113 of the heat transfer member 11. Then, the heat transfer member 11 rises in temperature by irradiation with infrared rays, and infrared rays are irradiated from the inclined surface 113 of the heat transfer member 11 toward the side surface 922 of the tooth 92. Furthermore, a part of infrared rays irradiated to the inclined surface 113 of the heat transfer member 11 reaches the side surface 922 of the tooth 92 by reflection. Thereby, infrared rays are applied to the side surfaces 922 of the teeth 92 of the laminated core 9 and the teeth 92 of the laminated core 9 are heated.
In the second example, since the gap between the inclined surface 113 of the heat transfer member 11 and the side surface 922 of the 92 becomes larger toward the center in the radial direction, the infrared rays emitted from the heater 2 tend to enter these gaps. Further, since the inclined surface 113 of the heat transfer member 11 is opposed to the side surface 922 of 92, the incident angle of the infrared ray that is reflected by the inclined surface 113 of the heat transfer member 11 and incident on the side surface of the tooth 92 is (Can be close to a right angle with respect to the side surface of the tooth 92). Therefore, the heating efficiency can be increased.

The lid member 13 is a member that covers the end surface 94 of the laminated core 9. The lid member 13 blocks the infrared rays emitted from the heater 2 so that the end surface 94 of the laminated core 9 is not directly irradiated. The lid member 13 also has a function of transmitting the heat of the heater 2 to the heat transfer member 11 and a function of preventing or suppressing the deformation of the laminated core 9.
The lid member 13 is formed in a plate shape, for example. Similarly to the heat transfer member 11, the lid member 13 is formed of a material having a high thermal conductivity such as copper (particularly a material having a higher thermal conductivity than the material of the laminated core 9).
An opening that penetrates in the axial direction is formed at the center of the lid member 13 in the radial direction. The opening is formed with an inner diameter through which one or a plurality of heaters 2 can be inserted. In addition, a predetermined number (here, the same number as the heat transfer member 11) of recesses or through-holes with which the heat transfer member 11 can be engaged is formed on the inner peripheral surface of the opening with a predetermined interval in the circumferential direction. It is formed. In FIG. 2, the structure by which the recessed part which can engage each heat-transfer member 11 is shown. However, the structure by which the through-hole which can penetrate each heat-transfer member 11 may be formed.
Further, the lid member 13 is formed so as to come into contact with one end surface of the connecting member 12 in the axial direction when coupled to the heat transfer member 11. For example, the inner diameter of the opening of the lid member 13 is set to be smaller than the outer diameter of the connecting member 12.

With this configuration, the lid member 13 is attached to and detached from the heat transfer member 11 from the end opposite to the side integrally joined by the connecting member 12 (the lower end in FIG. 2). Is possible.
Furthermore, the lid member 13 is preferably formed in a size and shape that covers the entire end surface 94 of the laminated core 9 in a state where the jig 1 is attached to the laminated core 9. If the lid member 13 has a size and shape that can cover the entire end surface 94 of the laminated core 9, it is possible to prevent the end surface 94 of the laminated core 9 from being directly irradiated with infrared rays from the heater 2. Furthermore, the deformation of the laminated core 9 can be prevented or suppressed by pressing the end face 94 of the laminated core 9 uniformly.

  The heat shield member 14 is a member that prevents or suppresses heat transfer from the lid member 13 to the end surface 94 of the laminated core 9. In order to realize this function, the heat shield member 14 is formed of a material having a lower thermal conductivity than the heat transfer member 11 and the lid member 13. For example, the heat shield member 14 is formed of ceramic or the like. The heat shield member 14 is detachably stacked on the surface of the lid member 13 near the end surface 94 of the laminated core 9. For example, the heat shield member 14 is formed in substantially the same size and shape as the lid member 13 when viewed in the axial direction. With such a configuration, the heat shield member 14 can be attached to and detached from the heat transfer member 11 similarly to the lid member 13. When the jig 1 is attached to the laminated core 9, the heat shield member 14 is interposed between the end surface 94 of the laminated core 9 and the lid member 13. For this reason, it can prevent or suppress that heat is transmitted from the cover member 13 to the laminated core 9 by conduction or radiation.

  Next, the procedure of the annealing method according to the embodiment of the present invention will be described. The annealing method according to the embodiment of the present invention is performed in a posture in which one end face 94 of the laminated core 9 faces upward (a posture in which the axis of the laminated core 9 is substantially vertical).

First, as shown in FIG. 1, the jig 1 is attached to the laminated core 9, and one or more heaters 2 are inserted into the inner peripheral side of the laminated core 9. That is, one lid member 13 and one heat shield member 14 are placed on a support base and the like, and the laminated core 9 is placed on the upper side thereof. When annealing the plurality of laminated cores 9 simultaneously, the plurality of laminated cores 9 are coaxially stacked. Further, the heat shield member 14 is placed on the upper end surface 94 of the laminated core 9, and the lid member 13 is placed on the heat shield member 14. Thereby, both end surfaces 94 of the laminated core 9 are covered with the heat shield member 14 and the lid member 13, respectively. Further, the end surface 94 of the laminated core 9 is in contact with the heat shield member 14 and is not in direct contact with the lid member 13.
In this state, the heat transfer member 11 is inserted into the inner peripheral side of the laminated core 9 from above. When the heat transfer member 11 is inserted, each heat transfer member 11 engages with a recess formed on the inner peripheral surface of the lid member 13 and the heat shield member 14 (contacts the inner peripheral surface of the recess). Further, each heat transfer member 11 enters each slit 93 of the laminated core 9 as shown in FIGS. Further, the connecting member 12 is placed on the upper surface of the lid member 13. Thereby, the heat transfer member 11 is positioned at positions where both ends in the axial direction protrude from the end face 94 of the laminated core 9. Furthermore, the upper end surface 94 of the laminated core 9 is pressed by the dead weight of the lid member 13, the heat shield member 14, and the heat transfer member 11.
In this state, the teeth 92 of the laminated core 9 are exposed without being covered with the jig 1 (see FIGS. 3 to 5).

The heater 2 is directly and axially uniform on the top surface 921 of the teeth 92 and a predetermined surface of the heat transfer member 11 (inner surface 111 in the first example, inclined surface 113 in the second example). It is arrange | positioned so that infrared rays can be irradiated. For example, when a single heater 2 is used, the single heater 2 is disposed at the center on the inner peripheral side of the laminated core 9. When a plurality of heaters 2 are used, the plurality of heaters 2 are arranged at equal distances from the center of the laminated core 9 at equal intervals in the circumferential direction.
Further, the axis of the heater 2 is preferably parallel to the axis of the laminated core 9. According to such a configuration, the distance between the heater 2 and the teeth 92 and the heat transfer member 11 can be made uniform over the entire length of the laminated core 9 in the axial direction. Therefore, infrared rays with uniform intensity can be irradiated over the entire length of the teeth 92 and the heat transfer member 11.

  Then, the heater 2 is energized to heat the laminated core 9 until it reaches a predetermined temperature. The “predetermined temperature” is preferably 700 ° C. or higher. The “predetermined temperature” may be 750 ° C., which is the same as the heating temperature in the conventional annealing method.

  As described above, the intermediate portion of the heater 2 in the axial direction is disposed on the inner peripheral side of the laminated core 9. For this reason, the laminated core 9 is heated from the inner peripheral side (side on which the teeth 92 are formed). That is, since the top surface 921 of the tooth 92 is exposed without being covered with the jig 1, the infrared rays emitted from the heater 2 are directly irradiated on the top surface 921 of the tooth 92. Infrared rays emitted from the heater 2 are also applied to the inner surface 111 or the inclined surface 113 of the heat transfer member 11 inserted in the slit 93. When the heat transfer member 11 is irradiated with infrared rays and rises in temperature, it transfers heat to the side surface 922 of the tooth 92 by conduction, radiation, or reflection. As described above, according to the first example (see FIG. 5A), when the inner surface 111 of the heat transfer member 11 is irradiated with infrared rays from the heater 2, the temperature of the heat transfer member 11 rises. Then, heat is transferred from the circumferential side surface 112 of the heat transfer member 11 to the side surface 922 of the tooth 92 by conduction or radiation. On the other hand, according to the 2nd example (refer to Drawing 5 (b)), when infrared rays are irradiated to inclined surface 113 of heat transfer member 11 from heater 2, heat transfer member 11 will rise in temperature by a part. Infrared rays are irradiated toward the side surface 922 of the tooth 92. Further, the remaining infrared rays are reflected by the inclined surface 113 of the heat transfer member 11 and applied to the side surfaces 922 of the teeth 92. As a result, the side surface 922 of the tooth 92 is irradiated with infrared rays, and the tooth 92 is heated.

  Since the heat transfer member 11 is formed of a material having a high thermal conductivity (particularly a material having a higher thermal conductivity than the laminated core 9), the temperature distribution in the axial direction of the heat transfer member 11 is uniform. For this reason, the heat transmitted from the heat transfer member 11 to the side surface 922 of the tooth 92 is also uniform in the axial direction. Therefore, uneven temperature of the laminated core 9 can be prevented or suppressed.

Further, the end surface 94 of the laminated core 9 is covered with the lid member 13 of the jig 1. For this reason, the infrared rays are not directly applied to the end surface 94 of the laminated core 9 from the heater 2. With such a configuration, uneven temperature can be prevented or suppressed. That is, when the end surface 94 of the laminated core 9 is exposed, the infrared rays emitted from the heater 2 are directly applied to the end surface 94 of the laminated core 9. For this reason, the temperature of the end surface 94 of the laminated core 9 and the vicinity thereof is higher than that of the intermediate portion in the axial direction. As a result, uneven temperature occurs in the laminated core 9. On the other hand, according to the embodiment of the present invention, infrared rays are not directly irradiated from the heater 2 to the end surface 94 of the laminated core 9. For this reason, the local temperature rise of the end surface 94 and its vicinity can be prevented or suppressed, and as a result, uneven temperature can be prevented or suppressed.
Furthermore, if the heat shielding member 14 is interposed between the end surface 94 of the laminated core 9 and the lid member 13, heat transfer by conduction or radiation is prevented from the lid member 13 to the end surface 94 of the laminated core 9. Can be suppressed. Therefore, according to such a configuration, the effect of preventing or suppressing uneven temperature can be further enhanced.

The heater 2 and the heat transfer member 11 are longer than the dimension of the laminated core 9 in the axial direction. With such a configuration, the amount of heat transferred to the teeth 92 of the laminated core 9 can be increased to shorten the heating time. That is, the heat transfer member 11 is irradiated with infrared rays from the heater 2 not only on the inner peripheral side of the laminated core 9 but also outside the laminated core 9. Further, when the lid member 13 is heated by infrared irradiation, it transfers heat to the heat transfer member by conduction. Therefore, the amount of heat transferred to the teeth 92 of the laminated core 9 can be increased as compared with a configuration in which the jig 1 is not used and a configuration in which the heat transfer member 11 of the jig 1 does not protrude from the end face 94 of the laminated core 9.
And since the lid | cover member 13 which covers the end surface 94 of the lamination | stacking core 9 is provided in the jig | tool 1, the calorie | heat amount given to the lamination | stacking core 9, preventing the infrared rays being directly irradiated to the end surface 94 of the lamination | stacking core 9 Can do more. That is, in the configuration in which the jig 1 is not used or the configuration in which the lid member 13 is not provided on the jig 1, if the dimension in the axial direction of the heater 2 is increased in order to shorten the heating time, the end surface 94 of the laminated core 9 is increased. As a result, the amount of infrared rays irradiated on the surface increases, and uneven temperature tends to occur. On the other hand, according to the embodiment of the present invention, it is possible to prevent or suppress the local temperature rise in the end surface 94 of the laminated core 9 and the vicinity thereof, so that the heating time can be shortened while preventing or suppressing the uneven temperature. Can be planned.

After the laminated core 9 reaches a predetermined temperature, heating by the heater 2 is stopped. Thereafter, the laminated core 9 is gradually cooled. The annealing conditions (for example, the method and temperature history) may be the same as those of the conventional annealing method. For example, conventional general furnace cooling or air cooling can be applied. Therefore, the description is omitted.
In order to increase the cooling efficiency, the heat shield member 14 may be removed during slow cooling. In this way, the heat of the laminated core 9 can be released through the lid member 13. Therefore, the cooling efficiency can be increased.

  In the embodiment of the present invention, after the laminated core 9 reaches a predetermined temperature, the cooling is started immediately. That is, in the conventional annealing method in which heating is performed using a heating furnace, heating is continued for a predetermined time (for example, about 2 hours) for soaking even after the laminated core 9 reaches a predetermined temperature. It was. For this reason, in the conventional annealing method, “time until the laminated core 9 reaches a predetermined temperature” and “time for soaking” are necessary as the heating time. On the other hand, in the annealing method according to the embodiment of the present invention, the laminated core 9 can be heated from the inner peripheral side and the jig 1 can be used to equalize the temperature. For this reason, only “time until the laminated core 9 reaches a predetermined temperature” is required as the heating time, and “time for soaking” is not necessary.

  The laminated core 9 is pressed by the weight of the jig 1. Therefore, deformation of the laminated core 9 can be prevented or suppressed.

  The annealing of the laminated core 9 is preferably performed in a non-oxidizing atmosphere in order to prevent oxidation of the electrical steel sheet 91 constituting the laminated core 9. For example, as shown in FIG. 6, a configuration in which the chamber 8 is filled with a non-oxidizing gas and the laminated core 9 is annealed therein can be applied. The configuration of the chamber 8 is not particularly limited, and various conventionally known chambers can be applied. In short, any configuration may be used as long as the inside can be maintained in a non-oxidizing atmosphere. In the embodiment of the present invention, since the laminated core 9 is heated using the heater 2, the chamber 8 may not include the heater 2.

According to the embodiment of the present invention, the laminated core 9 is heated from the inner peripheral side by infrared rays emitted from the heater 2. Since the heater 2 is arranged on the inner peripheral side of the cylindrical laminated core 9, infrared rays are applied over the entire axial direction of the top surface 921 of the teeth 92 and the inner surface 111 or the inclined surface 113 of the heat transfer member 11. Can be irradiated almost uniformly. Further, as compared with a configuration using a heating furnace, the heater 2 and the heat transfer member 11 which are heat sources (infrared sources) can be brought closer to the surfaces of the teeth 92 of the laminated core 9. Then, by using the jig 1, it is possible to equalize the heat in the axial direction. In particular, if the dimension of the heater 2 and the heat transfer member 11 in the axial direction is longer than the dimension of the laminated core 9 in the axial direction, the amount of heat transferred to the laminated core 9 can be increased.
For this reason, according to such a structure, the laminated core 9 can be heated uniformly in a short time, and the “time until the laminated core 9 reaches a predetermined temperature” can be shortened. In particular, when the heater 2 that emits near-infrared rays is applied, the responsiveness of temperature rise can be improved.

Furthermore, according to the embodiment of the present invention, since uneven heat can be prevented or suppressed during heating, after the laminated core 9 reaches a predetermined temperature, it is immediately cooled gradually without continuing heating for soaking. Can start. Therefore, “time for soaking” can be omitted, and the heating time can be shortened.
As described above, according to the embodiment of the present invention, the heating time in annealing and the soaking time can be reduced, and the productivity of the laminated core 9 can be improved.

  And according to embodiment of this invention, iron loss can be reduced, shortening heating time. That is, the punched magnetic steel sheet 91 has a substantially simple circular outer periphery, but has an unevenness on the inner peripheral side because the teeth 92 are formed. For this reason, the inner peripheral side has a longer cut and larger distortion than the outer peripheral side. Further, the magnetic flux density generated when the motor is operated is concentrated on the inner peripheral side, and the influence of iron loss deterioration due to strain is large on the inner peripheral side. Therefore, in order to reduce the iron loss, it is necessary to remove the strain by increasing the effect of annealing particularly on the inner peripheral side. In the embodiment of the present invention, the heater 2 and the heat transfer member 11 are disposed on the inner peripheral side of the laminated core 9. And while irradiating infrared rays directly on the surface of the tooth | gear 92 formed in the inner peripheral side of the lamination | stacking core 9, the lamination | stacking core 9 is heated from the inner circumference side by conduction, radiation | emission, and reflection from the heat-transfer member 11. FIG. For this reason, the inner peripheral side of the laminated core 9 can surely reach a predetermined temperature. Furthermore, since the inner peripheral side reaches the predetermined temperature earlier than the outer peripheral side, the time during which the inner peripheral side is maintained at the predetermined temperature can be made longer than the outer peripheral side. Therefore, the effect of annealing on the inner peripheral side can be enhanced, and the iron loss can be reduced. Thus, according to the embodiment of the present invention, it is possible to reduce the iron loss while shortening the heating time.

Further, the heat transfer member 11 is inserted into the slit 93, and the teeth 92 are also heated by the heat transfer member 11. That is, the heat transfer member 11 functions as a heat source (infrared ray source) for heating the teeth 92 together with the heater 2. For this reason, if the jig 1 has the heat transfer member 11, the heating time can be further shortened. Further, if the heat transfer member 11 is formed of a material having a higher thermal conductivity than the laminated core 9, the axial direction of heat transferred from the heat transfer member 11 to the teeth 92 can be made uniform. . Therefore, it is possible to shorten the heating time while sufficiently obtaining the effect of removing strain by annealing.
For example, when the temperature deviation is large, if the target temperature is set with reference to the part where the temperature rise is the fastest, the effect of annealing may not be sufficiently obtained at the part where the temperature rise is slow. On the other hand, if the target temperature is set with reference to the part where the temperature rise is the slowest, the temperature becomes too high at the part where the temperature rise is fast, and there is a possibility that the effect on the coating or the deformation of the laminated core 9 itself may occur. On the other hand, according to the embodiment of the present invention, the temperature of the entire laminated core 9 can be increased uniformly by preventing or suppressing the temperature deviation. For this reason, the effect of annealing can be obtained on the entire laminated core 9, and a portion where the temperature becomes too high can be prevented.

  When annealing a plurality of laminated cores 9, a plurality of laminated cores 9 are arranged so as to be overlapped (or arranged side by side) in the axial direction, and one or a plurality of rod-shaped heaters 2 and heat transfer members 11 are overlapped. The laminated cores 9 are arranged so as to penetrate through the inner peripheral side of the laminated core 9. According to such a structure, since the several laminated core 9 can be heated simultaneously, the improvement of the productivity of the laminated core 9 can be aimed at. Although FIG. 1 shows a configuration in which two laminated cores 9 are stacked, the number of stacked cores 9 to be stacked is not limited.

  1 shows a configuration in which the heater 2 is linearly formed, the shape of the heater 2 is not limited. For example, the structure to which the U-shaped heater 2 is applied may be used. Further, in the above description, the configuration in which the heater 2 is disposed only on the inner peripheral side of the laminated core is shown, but the present invention is not limited to this configuration. For example, from the viewpoint of increasing the efficiency of heating, a configuration in which the heater 2 is further disposed outside the laminated core 9 as necessary may be employed.

  As mentioned above, although embodiment of this invention was described in detail with reference to drawings, the said embodiment only showed the specific example in implementation of this invention. The technical scope of the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the spirit of the present invention, and these are also included in the technical scope of the present invention.

  For example, the number of heaters 2 used for heating the laminated core 9 is not limited. The number of heaters 2 is appropriately set according to the dimensions and shape of the laminated core 9 to be heated. Moreover, in the said embodiment, although the structure which piles up the two laminated cores 9 in the axial direction and heats simultaneously is shown, the number of the laminated cores 9 heated simultaneously is not limited. Only one laminated core 9 may be heated, or three or more laminated cores 9 may be stacked and heated simultaneously.

  INDUSTRIAL APPLICABILITY The present invention can be applied to annealing for removing strain of a laminated core configured by laminating electromagnetic steel sheets. Moreover, it is not limited to the laminated core comprised by laminating | stacking an electromagnetic steel plate, It can apply to the annealing of another various laminated core.

1: Jig, 11: Heat transfer member, 111: Inner side surface, 112: Circumferential side surface (first example), 113: Inclined surface (second example), 12: Connecting member, 13: Lid member, 14 : Heat shield member, 2: Heater, 8; Chamber, 9: Laminated core, 91: Electrical steel sheet, 92: Teeth, 921: Top surface, 922: Side surface, 93: Slit

Claims (7)

A laminated core annealing method in which a plurality of teeth are formed on the inner peripheral side having a laminated electrical steel sheet,
A rod-shaped heater is disposed on the inner peripheral side of the laminated core, and a rod-shaped or plate-shaped heat transfer member made of a material having a higher thermal conductivity than the laminated core is inserted between the teeth,
The method for annealing a laminated core, wherein the teeth and the heat transfer member are heated by the heater, and the teeth are also heated by the heat transfer member.   The axial dimension of the heater and the heat transfer member is longer than the axial dimension of the laminated core, and end portions of the heater and the heat transfer member protrude from an end surface of the laminated core. Item 2. A method for annealing a laminated core according to Item 1.   The method for annealing a laminated core according to claim 1, wherein an end surface of the laminated core is covered with a lid member joined to the heat transfer member.   The heat shield member made of a material having a lower thermal conductivity than the lid member and the heat transfer member is provided on the end member side surface of the laminated core of the lid member. The method for annealing a laminated core as described.   One end surface of the laminated core is directed upward, the lid member is placed on the one end surface, and the weight of the lid member and the heat transfer member is applied to the one end surface of the laminated core. The method for annealing a laminated core according to claim 3 or 4, characterized in that:   The method for annealing a laminated core according to claim 1, wherein the heater is a heater that emits infrared rays.   The method for annealing a laminated core according to claim 6, wherein the heater is a rod-shaped halogen heater.

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