JP2013165626A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat transfer efficiency between a stator and a housing and improve heat radiation performance of a housing surface in a motor where a stator core is internally fitted in the housing.SOLUTION: A motor 10 includes: a stator 30 formed by laminated steel plates 20; and a housing 12 in which the stator is internally fitted. A filler 18 fills a gap between the stator 30 and the housing 12. A heat radiation paint is applied to an outer periphery of the housing 12.

Description

  The present invention relates to a motor having a structure in which a stator core is fitted in a housing.

  When the motor is operated, the rotor and the stator generate heat due to loss generated in the rotor and the stator. Most of the heat generation is transmitted from the stator core to the housing and is radiated from the surface of the housing.

  In Patent Document 1, a ceramic paint that reflects visible light and near infrared light, emits far infrared light and blocks heat conduction is applied to the inner surface of the opposite output shaft side bracket facing the motor winding, and is applied to the outer peripheral surface of the frame. A motor coated with a hybrid far-infrared radiation paint is disclosed. According to this, the amount of heat radiation from the surface of the frame can be reduced while reducing the temperature rise due to radiant heat from the motor windings.

JP 2009-261118 A

  In a motor having a structure in which the stator core is fitted in the housing, a gap is often formed between the outer peripheral surface of the stator core and the inner peripheral surface of the housing for manufacturing reasons. In such a location, there is a problem that heat transfer from the stator core to the housing deteriorates due to the presence of the air layer.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for enhancing the heat transfer efficiency between the stator and the housing and enhancing the heat dissipation performance from the housing surface.

  A motor according to an aspect of the present invention is a motor having a structure in which a stator composed of laminated steel plates is fitted in a housing, and a space between the stator and the housing is filled with a filler, and the outer periphery of the housing is Thermal coating is applied.

  According to this aspect, the heat generated in the rotor and the stator can be transmitted to the housing with high heat transfer efficiency, and can be radiated from the housing surface with high efficiency. Therefore, the heat dissipation performance of the motor is increased and the motor efficiency is improved.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, in the motor of the structure where the stator was fitted in the housing, while improving the heat transfer efficiency between a stator and a housing, the heat dissipation performance from the housing surface can be improved.

It is sectional drawing which cut | disconnected the motor which concerns on one Embodiment of this invention by the surface orthogonal to an output shaft. (A) is a figure explaining a mode that a magnetic steel sheet is punched out, (b) is typical sectional drawing of a part of punching die. It is a top view of the steel plate concerning one embodiment. It is an enlarged view of the flat part of FIG. 3, and the convex part vicinity. It is a figure which shows an example of an electromagnetic steel plate. FIG. 6 is an enlarged view of the vicinity of the flat part and the convex part of FIG. 5.

  FIG. 1 is a cross-sectional view of a motor 10 according to an embodiment of the present invention cut along a plane orthogonal to an output shaft. In FIG. 1, only the stator 30 and the housing 12 are shown to simplify the description, and the structure of the rotor, the shaft, the winding, and the like is omitted.

  The motor 10 is, for example, a synchronous motor (IPM motor) having a structure in which a permanent magnet is embedded in the rotor, but may be another type of motor. Since the structure of the rotor and the stator, the operating principle of the rotor, and the like are the same as those of the prior art, detailed description is omitted in this specification.

  The stator 30 is formed by laminating a number of thin plate-like (for example, 0.5 mm thick) electromagnetic steel plates 20 that have been punched into the same shape. The stator 30 is fitted to the inner periphery of the housing 12 by shrink fitting, for example. A coil is wound around the plurality of slots 16 formed in the stator 30.

  The housing 12 is made of, for example, aluminum die cast, cast iron, or steel plate, and supports the weight of the rotor and the stator and has a role of radiating heat generated in the rotor and the stator to the outside of the motor. In order to enhance the heat dissipation performance, a large number of heat dissipating fins (one of which is indicated by 14) extending in a direction parallel to the output shaft of the motor is installed on the outer periphery of the housing 12.

  The outer periphery of the stator 30 is not a perfect circle, and a plurality of convex portions 22a to 22d are formed as illustrated. The reason for this will be described below.

  FIG. 2 is a diagram for explaining a process of punching an electromagnetic steel sheet from a long steel sheet. In general, the electromagnetic steel sheet is formed by pressing a punching die against the long steel sheet 50 to form a plurality of electromagnetic steel sheets at a time. Here, a punching die for forming two electromagnetic steel plates 52a and 52b at a time is considered.

  In order to save material costs, adjacent electrical steel sheets are preferably stamped as close as possible. As shown in FIG. 2, when the outer peripheries of adjacent electromagnetic steel sheets are in contact with each other (see A part in the figure), that is, when the center distance M between adjacent electromagnetic steel sheets is equal to the diameter of the electromagnetic steel sheet, the material efficiency Is the highest.

  However, as shown in FIG. 2 (b), the part of the punching die for forming the part A becomes very thin, and this part is easily deformed due to repeated load at the time of punching. There is a problem that the life of the die is reduced and the yield of the electromagnetic steel sheet punched with the deformed die is deteriorated.

  Therefore, as shown in the plan view of FIG. 3, the magnetic steel sheet 20 according to the present embodiment is provided with flat portions 26 a to 26 d obtained by cutting a part of the outer periphery at four locations on the outer periphery, and from the flat portion toward the outside. The protrusions 22a to 22d projecting are provided.

  FIG. 4 is an enlarged view of the vicinity of the flat portion 26a and the convex portion 22a (B portion) in FIG. A dotted line 24 in the figure is an extension of the outer peripheral line other than the flat portion. As can be seen from FIG. 4, there is a gap C between the convex portion 22 a and the outer circumferential line 24. Because of this gap C, a distance of 2C is ensured between the adjacent electromagnetic steel sheet and the outer periphery of the adjacent electromagnetic steel sheet even when the center distance M similar to that in FIG. 2 is maintained. Can do. Therefore, it is possible to ensure the strength of the die that forms this portion, and it is possible to prevent the life of the die and the yield of the electromagnetic steel sheet from being deteriorated.

  FIG. 5 is a plan view of a magnetic steel sheet 60 according to another embodiment. Similarly to the electromagnetic steel plate 20 of FIG. 3, the electromagnetic steel plate 60 is also provided with flat portions 66a to 66d obtained by cutting a part of the outer periphery at four locations on the outer periphery, and a convex portion 62a protruding outward from the flat portion. -62d are provided.

  FIG. 6 is an enlarged view of the vicinity of the flat portion 66a and the convex portion 62a (D portion) in FIG. A dotted line 64 in the figure is an extension of the outer peripheral line other than the flat portion. As in FIG. 4, a gap E having the same size as the gap C in FIG. 4 exists between the convex portion 62 a and the outer peripheral line 64. However, in the example of FIG. 6, the amount of depression of the flat portion 66a from the outer peripheral line is smaller than the amount of depression of the flat portion 26a in FIG. As described above, the distance between the bottom of the slot 16 of the stator 30 and the stator outer peripheral surface is reduced by reducing the amount of dent in the flat portion while maintaining the distance for securing the strength of the punching die between the adjacent electromagnetic steel sheets. The distance can be increased. As a result, the magnetic flux density in the vicinity of the bottom of the slot is reduced, so that heat generation from the stator can be reduced.

  In addition, in the example shown in FIGS. 3-6, although the flat part and the protrusion part are provided in four places of the outer periphery of an electromagnetic steel plate, according to the aspect of arrangement | positioning of the electromagnetic steel sheet in a punching die, a flat part and a protrusion part are provided. The number can be different.

  Returning to FIG. 1, the heat transfer path of the motor 10 will be described. Heat generated by a rotor (not shown) is transmitted to the stator 30 by radiation. The heat of the stator 30 is transferred to the housing 12 by heat conduction, and is released from the surface of the housing 12 by radiation. Therefore, if the thermal conductivity between the stator 30 and the housing 12 is improved, the motor can be radiated efficiently.

  Since the stator is a laminated steel plate, the outer peripheral surface of the stator 30 is not smooth and has slight irregularities. Further, the inner peripheral surface of the housing 12 is not smooth. Therefore, even if the stator 30 is fitted into the housing 12 by shrink fitting or the like, a gap is generated between both surfaces. In such a place, heat conduction from the stator core to the housing deteriorates due to the presence of the air layer.

  Therefore, in the present embodiment, a filler having a high thermal conductivity such as silicone resin is applied to the outer peripheral side surface of the stator 30 and then the housing 12 is externally fitted. Therefore, as shown in FIG. 1, a filler layer 18 is formed between the stator 30 and the housing 12. By doing so, the gap generated between the stator and the housing can be effectively filled with the filler, and heat transfer from the stator to the housing is improved, so that the heat dissipation performance of the motor is improved. In addition, by applying the filler to the stator first, the outer fitting operation of the housing is facilitated, and the filler is not consumed wastefully.

  The inner peripheral surface of the housing 12 is adapted to the shape thereof so that no gaps are formed between the convex portions 22a to 22d and the flat portions 26a to 26d of the stator 30 and the inner peripheral surface of the housing. Recesses 16a to 16d are formed. By doing so, even if the outer periphery of the stator 30 has a flat portion and a convex portion deviating from a perfect circle, it is possible to avoid adversely affecting the heat transfer from the stator to the housing.

  The outer periphery of the housing 12 is coated with a paint having a high thermal emissivity and excellent heat dissipation. An example of such a paint is a paint in which a heat radiation filler is mixed with a heat-resistant paint such as an acrylic resin or a silicone resin. The thermal radiation filler is a compound such as Si, Al, C, or O, and the filler alone has excellent heat transfer performance such as a thermal conductivity of 170 w / mK and a thermal emissivity of 0.97. Such a paint is commercially available from Hamaguchi Urethane Co., Ltd. under the trade name “HamaCool”. In addition, you may make it stick to the outer peripheral surface of a housing what mixed the heat radiation filler with the acrylic resin or the polypropylene resin, and processed into the sheet form instead of the thermal radiation coating material.

  As described above, according to the present embodiment, a paint having a high heat dissipation performance is applied to the outer periphery of the stator while filling the filler having a high thermal conductivity between the stator and the housing. Thereby, the heat generated in the rotor and the stator can be transmitted to the housing with high heat transfer efficiency, and can be radiated from the housing surface with high efficiency. Therefore, the heat dissipation performance of the motor is increased and the motor efficiency is improved.

  In addition, the inner peripheral surface of the housing is processed so as to conform to the outer peripheral shape of the electromagnetic steel plate constituting the stator, and the housing is externally fitted after the filler is applied to the stator. Thereby, the possibility that an air layer not filled with the filler is generated can be reduced, and the heat dissipation performance is improved.

  The embodiment of the present invention has been described above. It is to be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to combinations of the respective components, and such modifications are within the scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Motor, 12 Housing, 16a Concave part, 18 Filler layer, 20 Magnetic steel sheet, 22a Convex part, 26a Flat part, 30 Stator, 60 Electromagnetic steel sheet, 62a Convex part, 66a Flat part

Claims (4)

A motor having a structure in which a stator composed of laminated steel sheets is fitted in a housing,
The space between the stator and the housing is filled with a filler,
A motor characterized in that a heat radiation paint is applied to the outer periphery of the housing.   2. The motor according to claim 1, wherein at least a part of the laminated steel plate has a shape deviating from a perfect circle, and an inner peripheral surface of the housing is processed to match the shape.   3. The motor according to claim 1, wherein the motor is fitted into the housing after a filler is applied to an outer peripheral side surface of the stator. 4.   4. A flat part in which a part of the circumference is cut off and a convex part protruding outward from the flat part are formed on the outer periphery of the laminated steel sheet. The motor described.

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