JP3430558B2 - Electric motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated iron core for an electric motor. 2. Description of the Related Art In recent years, the use of electric motors at different rotational speeds by using control devices has been increasing. For this reason, it is often required to make the characteristics of the motor uniform (for example, the uniformity of the torque generated during one rotation of the motor, and the uniformity of the mutual performance of the motors), and with the expansion of the application range of the motor, The demand for smaller and lighter is also increasing. [0003] A conventional motor will be described below. FIG. 5 shows a conventional method for fixing a laminated iron core of an electric motor. In FIG. 5, a laminated core has been manufactured by providing a half-hole-shaped coupling projection g on the core and laminating it to a predetermined thickness in a mold. FIG. 6 also shows a conventional method of fixing a laminated iron core of a motor. In FIG. 6, a plurality of portions are welded and fixed to the outer peripheral portion of the iron core by electric welding such as TIG welding on the basis of the outer periphery. In recent years, a welding method using a laser has been developed as a welding method replacing electric welding such as TIG welding, as shown in Japanese Patent Application Laid-Open No. 56-66023. [0006] However, none of the above-mentioned laminated cores is sufficient in accuracy of the inner diameter and rigidity of the laminated core, which are factors of motor characteristics. [0007] For example, a semi-blanked coupling projection g shown in FIG.
In the laminated iron core provided with, it was fixed on the basis of the coupling projection, and was not laminated on the basis of the inner diameter. The cylindricity was about 0.2 mm with an inner diameter of about 25 mm and a thickness of about 20 mm.
Also, the location of the coupling projection is often limited by the shape of the core, so that it is not possible to fix the teeth portion having an inner diameter where vibration or the like is likely to occur, or conversely, the slot portion where the winding is inserted to provide the coupling projection. There were problems such as reducing the area. Further, even when the outer peripheral portion of the iron core shown in FIG. 6 is fixed by electric welding or the like, the welded portion can be welded only at the edge portion. When there is no edge portion, it is necessary to provide a welding margin and perform welding. . Also, when trying to weld the inner diameter, it was not possible to complete welding with an iron core having an inner diameter of 120 mm or less due to the size of the torch of the welding machine. An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a motor having a laminated iron core having high rigidity and having high cylindricity with reference to the inner diameter. [0010] In order to achieve this object, the electric motor of the present invention uses laser welding to weld the surfaces of the laminated iron cores facing the rotor to the teeth. It has a configuration based on the inner diameter of the laminated core. With this configuration, welding can be performed with reference to the inner diameter, so that a laminated iron core having high cylindricity can be obtained, and an electric motor having excellent and uniform characteristics can be obtained. Since the inner core is also a welded laminated iron core, the rigidity of the motor is improved, and the beat noise and vibration of the iron core can be prevented. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional perspective view of a laminated core of a motor according to an embodiment of the present invention. a is a laser weld, d
Is a teeth part, and i is a laminated iron core. FIG. 2 is a cross-sectional view in the output shaft direction of a motor using a laminated iron core of the motor according to one embodiment of the present invention. b is a laser weld, and e is a rotor. FIG. 3 is a cross-sectional view of a motor using a laminated iron core according to an embodiment of the present invention in a direction perpendicular to an output shaft. As shown in FIG. 1, the surface of the tooth portion d facing the rotor is laser-welded. As is generally known, laser welding can transmit the energy with an optical fiber, and even in a small part, energy can be transmitted in a range where the optical fiber reaches. In addition, since the optical beam can be narrowed down by an optical system transmission device using a lens, welding can be performed by giving a minimum heat energy to the required welding point, thereby reducing the effect of thermal strain on others. can do. Also,
This laser welding makes it possible to perform welding at any location where there is no welding margin on the rotor facing surface of the teeth, and as a result, it is characteristically necessary without being restricted by the welding margin or the shape of the semi-blanked connecting projection There is also an advantage that any shape can be freely selected. Since the iron core can be welded on the basis of the inner diameter, the cylindricity of the inner diameter accuracy of the laminated iron core can be improved to about 0.05 mm. Also, as is clear from FIGS. 2 and 3, this surface is the surface that receives the force of the magnetic flux from the rotor most. Therefore, it is easy to generate beats and vibrations of the iron core. Can be prevented. In the conventional method, when the inner diameter surface is to be welded, the torch of the welding machine cannot be completely inserted unless the inner diameter portion is φ120 mm or more in the conventional method. It is now possible to create a laminated core by welding the inner surface of a small electric motor. The effects of the present invention are summarized as follows. (1) Since welding can be performed on the basis of the inner diameter, the inner diameter accuracy (cylindricity) is improved as compared with the prior art. As a result, the characteristics of the electric motor are made uniform. (2) Since an arbitrary portion of the laminated core can be welded, the shape of the iron core with the highest priority on the characteristics can be obtained without being restricted by the welding margin or the location of the semi-blanked connecting projection. As a result, the size and weight of the electric motor can be reduced. (3) Since the surface facing the rotor, which cannot be fixed by the conventional method, can be fixed, it is possible to prevent the beat and vibration of the iron core. As a result, a motor with low noise and low vibration is obtained. (4) In the conventional welding method, the inner diameter is 120 mm.
With the following motors, it was difficult to weld the inner diameter of the iron core because the torch of the welding machine was not completely inserted. However, laser welding made it possible to perform welding without any welding margin at the inner diameter. As a result, the above effects can be obtained even with a small motor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional perspective view of a laminated core of a motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the motor in an output shaft direction according to an embodiment of the present invention. FIG. 4 is a cross-sectional view of a stator in a direction perpendicular to an output shaft of a motor according to one embodiment of the present invention. FIG. 4 is a top view of a laminated core of a motor according to another embodiment of the present invention. FIG. 6 shows a fixing method of a conventional motor. FIG. 6 shows a fixing method of a laminated core of a conventional motor. [Description of symbols] a, b, c, f laser welded part d teeth part e rotor g coupling protrusion i laminated core

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Matsu ▲ Saki ▼ Kagetaka 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Kazunori Morita 1006 Kadoma Kadoma, Kazuma, Osaka Matsushita Electric (72) Inventor Hiroya Motoi 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Sachiichi 1006 Kadoma Kadoma, Kazuma, Osaka Matsushita Electric Industrial Co., Ltd. In-house (72) Inventor Masayuki Morioka 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Minoru Chamura 1006 Odaka, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-68352 (JP, A) JP-A-5-122875 (JP, A) JP-A 4-76140 (JP, U) JP-A 56-66154 (JP, U) (58) Survey did Field (Int.Cl. ^7, DB name) H02K 1/18 H02K 15/02

Claims (1)

(57) comprising a stator with a laminated core having a plurality of teeth to the Claims 1] inner circumferential portion, and a rotor which adduction opposite the teeth, the Inside based on the inner diameter of the laminated core
An electric motor characterized in that an arbitrary cross section facing a rotor of each tooth portion is laser-welded in a state where a diameter accuracy is secured .