JP2009118628A - Molded motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded motor capable of perfectly eliminating a bearing current and of resolving wear, damage and breakdown on bearing parts absolutely only by forming a conductive layer on the molded motor in a simple, inexpensive way. <P>SOLUTION: After a coil 4 is wound around a stator core 2 covered with an insulating layer 3, the inner circumferential surface of a motor frame 8, which is integrally molded with insulating resin, is provided with a first conductive layer 18 and the outer circumferential surface of the motor frame is provided with a second conductive layer 20, thereby providing the conductive layer on the whole surfaces of the motor frame 8. This enables the stator core 2 wound by the coil 4 to be completely sealed by the first conductive layer 18 and the second conductive layer 20, and the coil 4 and a rotor 9 to be electrostatically shielded by the conductive layer. Therefore, the molded motor can be obtained in which bearing current is perfectly eliminated and wear, damage and breakdown of the bearing part due to a bearing current are resolved with perfection. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a molded motor.

  2. Description of the Related Art Conventionally, there is a molded motor in which a core is formed by winding a winding around a stator iron core with a molding resin to form a housing, and a rotor is built in through a bearing. In the above-mentioned molded motor, since the stator core and the winding are covered with the mold resin, it is not necessary to consider the grounding. However, when the inverter is used and the molded motor is used, the switching of the inverter is not necessary. Due to the steep voltage changes that occur sometimes, shaft damage and bearing current generated based on high-frequency induction may cause bearing damage called galvanic corrosion that occurs on the raceway surface of the inner ring part, outer ring part and the surface of the rolling conductor. is there. The present invention relates to a molded motor equipped with an electrolytic corrosion prevention device that occurs in a rotating electric machine using an inverter-driven bearing device that prevents bearing damage due to electrolytic corrosion.

  The mechanism of the occurrence of electrolytic corrosion of a conventional molded motor that does not take measures against electrolytic corrosion of the bearing will be described. A conventional molded motor with this type of electrolytic corrosion prevention function has a motor structure described in Patent Document 1, for example. A conventional brushless motor will be described with reference to FIGS.

  FIG. 17 is a structural cross-sectional view of a conventional molded motor disclosed in Patent Document 1. In FIG. In the figure, a mold motor 101 is a brushless DC motor, and an insulating layer 103 is formed on a stator core 102 in which steel plates are laminated, and a coil 104 is wound around the insulating layer 103. The stator core 102, the insulating layer 103, the coil 104, and a coil end portion 105, which is a part of the coil 104 and protrudes from the stator core, are covered with mold resin to form a substantially cylindrical motor frame 106. Has been.

  A donut-shaped wiring board 107 is attached to the output side of the motor frame 106 as shown in the figure. Since the mold motor 101 is a brushless DC motor, an inverter device that drives the mold motor 101 by PWM control is incorporated in the wiring board 107. A metal bracket 108 is embedded in the motor frame 106 on the output side end face of the motor frame 106. A rotor 109 is inserted inside the motor frame 106 through a gap. Two bearings 111 and 112 are attached to both sides of the rotating shaft 110 of the rotor 109. The two bearings are held by the mold resin of the bracket 108 and the motor frame 106, respectively, as shown in the figure. The rotor 109 can rotate with a rotating shaft 110 supported by two bearings 111 and 112.

  FIG. 18 is a model diagram showing a distribution state of electrostatic coupling capacitance between each part of the conventional molded motor of Patent Document 1. In FIG. As shown in the figure, since the coil 104 is wound around the stator core 102 that is a ferromagnetic body, the coil 104 has a relatively large equivalent inductance Lc. In general, in the molded motor, the coil end portion 105 is disposed at a position close to the rotor 109, and therefore, an electrostatic coupling capacitance Ccr exists between the coil 104 and the rotor 109. Since the coil 104 is disposed at a position close to the stator core 102 with the insulating layer 103 interposed therebetween, the coil 104 is relatively large between the coil 104 and the stator core 102 along the winding direction of the coil 104. There is an electrostatic coupling capacitance Ccs. Since the mold motor 101 is a brushless DC motor, generally, the gap between the stator core 102 and the rotor 109 is designed to be narrow so as to be within a range of 0.35 to 0.5 mm, for example. A relatively large air gap capacity Crs also exists between the stator core 102 and the rotor 109. Further, an electrostatic coupling capacitance Cbc exists between the coil 104 and the bracket 108, a Cbr exists between the bracket 108 and the rotor 109, and an electrostatic coupling capacitance Cbs exists between the stator core 102 and the bracket 108. Between the inner ring and the outer ring of the bearing 111, there is an electrostatic coupling capacitance Cb1 between the inner ring and the outer ring with a rolling element interposed therebetween.

  FIG. 19 is a side view showing the state of the bearing when the conventional mold motor of Patent Document 1 rotates at high speed. As shown in the figure, the rolling element 142 of the bearing 111 is in a state of floating in a hollow between the inner ring 114 and the outer ring 115 immersed in the lubricating oil 113 (hereinafter referred to as a fluid lubrication state). In this case, the inner ring 114 and the outer ring 115 are always non-conductive and sometimes conductive.

  FIG. 20 is a common mode equivalent circuit for explaining the waveforms of each part of the molded motor when the bearing of the conventional molded motor of Patent Document 1 is in a fluid lubrication state. As shown in the figure, an equivalent inductance Lc and electrostatic coupling capacitors Ccr, Ccs, Crs, Cbr, Cbc, Cbs, Cs, and Cb1 are formed, and a closed circuit 117 surrounded by a dotted line is formed.

  FIG. 21 is a time chart of each part for explaining a mechanism in which a discharge mode bearing current is generated when a bearing of a conventional molded motor of Patent Document 1 is in a fluid lubrication state. As described in Document 2, when the bearing is in a fluid lubrication state, when a common mode voltage 116 as illustrated is applied between the coil 104 and the ground by the inverter device incorporated in the wiring board 107. As a response voltage of the closed circuit 117 of the common mode voltage 116, a voltage between the inner ring and the outer ring as illustrated is generated between the inner ring 114 and the outer ring 115 of the bearing 111. This inner ring-outer ring voltage has a waveform that dampens and oscillates as shown in the figure at the rising edge of the common mode voltage due to the transfer characteristic inherent to the closed circuit 117. Next, the voltage charged between the inner ring and the outer ring of the bearing 111, that is, the parasitic capacitance between the inner ring and the outer ring of the bearing 111 (the parallel combined capacitance of the electrostatic coupling capacitances Cbr and Cb1) has a certain threshold value. If exceeded, the oil film of the lubricating oil 113 between the outer ring 115, the rolling element 142, and the inner ring 114 causes dielectric breakdown, and the voltage between the inner ring and the outer ring accumulated in the electrostatic coupling capacitance Cbr is discharged. Mode bearing current is generated. The bearing current of this discharge motor is a bearing current that occurs as a discharge phenomenon that occurs in the gap between the inner ring of the bearing, the rolling elements, and the outer ring, and directly causes bearing damage due to the discharge breakdown of the bearing. In the case of a 100 W class molded motor, the maximum peak current is about several tens of mA to several hundred mA, and the damage stress given to the bearing is large as described in Document 2.

  FIG. 22 is a side view showing the state of the bearing when the conventional mold motor of Patent Document 1 is rotating at a low speed. In this case, the inner ring 114 is always in contact with the outer ring 115 via the rolling elements 142 (hereinafter referred to as a boundary lubrication state), and the inner ring 114 and the outer ring 115 are in contact and are always electrically connected.

  FIG. 23 is a common mode equivalent circuit for explaining the waveforms of each part of the molded motor when the bearing of the conventional molded motor of Patent Document 1 is in the boundary lubrication state. The difference from the common mode equivalent circuit when the bearing described in FIG. 20 is in a fluid lubrication state is that the bearing 111 is always conducting and the switch, which is an electrical representation of the bearing 111, is in a closed state. is there. As shown in the figure, an equivalent inductance Lc and electrostatic coupling capacitors Csr, Ccs, Crs, Cbr, Cbc, Cbs, Cs, and Cb1 are formed, and a closed circuit 118 surrounded by a dotted line is formed.

  FIG. 24 is a time chart of each part for explaining the mechanism by which the bearing current in the conductive mode is generated when the bearing of the conventional molded motor of Patent Document 1 is in the boundary lubrication state. As described in Patent Document 2, when the bearing is in the boundary lubrication state, a common mode voltage 116 as illustrated in FIG. 24 is applied between the coil 104 and the ground from the inverter device incorporated in the wiring board 107. Then, as a response current of the closed circuit 118 of the common mode voltage 116, a bearing current in a conductive mode as illustrated in the bearing 111 is generated. This bearing current oscillates as shown at the rising edge of the common mode voltage due to the transfer characteristic inherent in the closed circuit 118. Here, the inner ring-outer ring voltage is maintained at 0 V because the inner ring 114 and the outer ring 115 of the bearing 111 are electrically connected. In the case of a 100W class molded motor, the bearing current of the conductive motor is about several tens of mA, and since the current passes through the bearing when the bearing is conducting, the damage stress applied to the bearing is the bearing in the discharge mode. Although it is not as large as the current, it is always generated whenever the common mode voltage is generated from the inverter device, and the frequency of the occurrence is high, and the damage stress on the bearing cannot be ignored.

  As described above, in the molded motor of Patent Document 1 that does not have a function to prevent electric corrosion due to a bearing current, a discharge mode bearing current having a large damage stress on the bearing generated when the bearing is in a fluid lubrication state, The bearing currents in the conductive mode that occur frequently when the bearing is in the boundary lubrication state can not ignore the damage stress on the bearing is generated, and the bearing current that gives damage stress to these bearings is generated, The electric corrosion of the bearing occurred.

  Next, a conventional molded motor with a countermeasure against electric corrosion will be described. Conventionally, this type of molded motor with an anti-corrosion prevention function is applied to the inner peripheral surface of the motor frame in the case of a molded motor with metal brackets on both the output side bracket and the non-output side bracket. An electroconductive paint is known which prevents the occurrence of electrolytic corrosion by short-circuiting the output-side bracket and the non-output-side bracket (for example, see Patent Document 3).

  FIG. 25 is a model diagram showing a distribution state of electrostatic coupling capacitance between each part of a conventional molded motor of Patent Document 3. As shown in the figure, the molded motor 119 is a brushless DC motor, and an insulating layer 121 is formed on a stator core 120 laminated with steel plates, and a coil 122 is wound around the stator core 120 via the insulating layer 121. ing. A donut-shaped wiring board 124 is provided in the vicinity of the coil end 123 protruding from the stator core 120 of the coil 122 and on the output side of the molded motor 119. Since the mold motor 119 is a brushless DC motor, an inverter device that drives the brushless DC motor by PWM control is incorporated in the wiring board 124. Furthermore, the stator core 120, the insulating layer 121, the coil 122, and the coil end 123 are integrally molded with a mold resin so that the exposed portion of the end surface of the stator core 120 is formed, and a substantially cylindrical motor frame. 125 is formed. A metal bracket 126 and a bracket 127 are embedded integrally with the motor frame 125 on the output side and the non-output side end surfaces of the motor frame 125, respectively.

  Next, a conductive paint is applied to the inner peripheral surface of the motor frame 125 including a portion where the bracket 126 and the bracket 127 are fitted to form a conductive layer 128. As described above, since the exposed portion of the end surface of the stator core 120 is formed in the motor frame 125, when the conductive paint is applied to the inner peripheral surface of the motor frame 125, the conductive paint and the stator core are electrically connected. Conducted to. Here, in general, the gap interval between the inner peripheral surface of the motor frame and the rotor needs to be designed to be within a range of, for example, 0.35 to 0.5 mm. It is necessary to apply a conductive paint with a uniform thickness on the inner peripheral surface of the motor frame so that a conductive layer of .05 mm or less is formed. Yes, when applying conductive paint using an airbrush, apply the mask attached to the outer peripheral surface after applying the entire surface of the motor frame 125 that has been masked to the outer peripheral surface with conductive paint using an airbrush. A process such as removal is required.

  Further, a rotor 129 is accommodated on the inner peripheral surface of the motor frame 125. A rotating shaft 130 made of metal is attached to the rotor 129, and brackets 126 to 127 are rotatably attached to both ends of the rotating shaft 130 via bearings 131 to 132, respectively. The bracket 126 is fitted to the output side end face of the motor frame 125, and the bracket 127 is fitted to the counter output side end face of the motor frame 125.

  In the molded motor having the above configuration, the bracket 126 to which the bearing 131 is attached and the metal bracket 127 to which the bearing 132 is attached are electrically short-circuited via the conductive layer 128. Therefore, the potentials of the two brackets 126 and 127 become the same potential, no circulating current is generated, and no bearing current is generated in the bearings 131 to 132, so that electric corrosion can be prevented. Is described.

  Next, the mechanism by which the bearing current is generated even in the molded motor 119 to which the electric corrosion countermeasure of Patent Document 3 is applied will be described. As shown in FIG. 28, since the coil 122 is wound around the stator core 120 that is a ferromagnetic body, a relatively large equivalent inductance Lc exists. Since the rotor 129 and the stator core 120 are arranged at positions close to each other so that the gap interval is within a range of 0.35 to 0.5 mm, for example, between the rotor 129 and the stator core 120. There is a relatively large air gap capacity Crs. Since the coil 122 is wound around the stator core 120 with the insulating layer 121 having a small thickness interposed therebetween, a relatively large electrostatic coupling capacitance Ccs is provided between the coil 122 and the stator core 120 along the coil winding direction. Exists. Between the coil end 123 and the rotating shaft 130, there is an electrostatic coupling capacitance Ccr1 between the coil 122 and the rotating shaft 130 as shown in the figure. In particular, although not shown here, when a rotating body made of a conductor such as a metal fan is attached to the rotating shaft 130, the electrostatic coupling capacity between the metal fan and the coil 122 is the rotating shaft. Since it is additionally connected in parallel to the electrostatic coupling capacitance Ccr1 between the coil 130 and the coil 122, the electrostatic coupling capacitance Ccr1 is an electrostatic coupling capacitance having a magnitude that cannot be ignored. Furthermore, an electrostatic coupling capacitance Cs also exists between the bracket 126 and the ground. Between the inner ring and the outer ring of the bearing 131, there is an electrostatic coupling capacitance Cb1 between the inner ring and the outer ring with the rolling element interposed therebetween. Between the inner ring and the outer ring of the bearing 132, there is an electrostatic coupling capacitance Cb2 between the inner ring and the outer ring with the rolling element interposed therebetween.

  FIG. 26 is a common mode equivalent circuit of a molded motor when the bearing of the conventional molded motor of Patent Document 3 is in a fluid lubrication state. As shown in the figure, a closed circuit 134 composed of an equivalent inductance Lc and electrostatic coupling capacitors Ccs, Ccr1, Crs, Cs, Cb1, and Cb2 is formed. When the bearing is in a fluid lubrication state, when a common mode voltage 133 similar to that illustrated in FIG. 21 is applied between the coil 122 and the ground by the inverter device incorporated in the wiring board 124, the common mode voltage 133 As a response voltage of the closed circuit 134, a voltage between the inner ring and the outer ring similar to that illustrated in FIG. 21 is generated between the inner ring and the outer ring of the bearing 126. The inner ring-outer ring voltage has a waveform that dampens and vibrates at the rising edge of the common mode voltage, similar to that shown in FIG. Next, there is a voltage charged between the inner ring and the outer ring of the bearing 131, that is, a parasitic capacitance between the inner ring and the outer ring of the bearing 131 (a parallel combined capacitance of capacitances Crs, Cb1, and Cb2). When the threshold value is exceeded, the oil film of the lubricating oil between the outer ring, the rolling element, and the inner ring causes dielectric breakdown, and the gap between the inner ring, the rolling element, and the outer ring of the bearing, as illustrated in FIG. A discharge phenomenon occurs, and a discharge mode bearing current with a large damage stress applied to the bearing, which directly causes bearing damage due to discharge breakdown at this time, is generated.

  FIG. 27 is a common mode equivalent circuit of a molded motor when the bearing of the conventional molded motor of Patent Document 3 is in a boundary lubrication state. The difference between FIG. 26 and FIG. 27 is that in FIG. 29 where the bearing is in a fluid lubrication state, the bearings 131 to 132 are electrically open, and in FIG. 30 where the bearing is in a boundary lubrication state, the bearings 131 to 132 are It is only a point that it is electrically conductive. As shown in the figure, a closed circuit 135 including an equivalent inductance Lc and electrostatic coupling capacitors Ccs, Ccr1, Crs, Cs, Cb1, and Cb2 is formed. When the bearing is in the boundary lubrication state, when a common mode voltage 133 similar to that shown in FIG. 24 is applied between the coil 122 and the ground, the response current of the closed circuit 135 of the common mode voltage 133 is obtained as a bearing current. A bearing current in a conductive mode similar to that shown in FIG. The bearing current has a waveform that vibrates in the same manner as illustrated in FIG. 24 at the rising edge of the common mode voltage due to the transfer characteristic inherent in the closed circuit 135. The bearing current of this conductive motor is a current that passes through the bearing when the inner ring and the outer ring of the bearing 131 are in conduction. Therefore, the damage stress applied to the bearing is not as great as the bearing current in the discharge mode. It is always generated and occurs frequently, and damage stress on the bearing cannot be ignored.

  As described above, even in the molded motor of Patent Document 3 in which two brackets are short-circuited with the conductive paint applied to the inner peripheral surface of the motor frame as a countermeasure against electrolytic corrosion due to the bearing current, the bearing is fluidized. When lubricated, a bearing current in the discharge mode with a large damage stress applied to the bearing is generated, and when the bearing is in the boundary lubricated state, the frequency of occurrence is high, and the conductive current bearing current cannot be ignored due to the damaged stress applied to the bearing. As a result, it is impossible to completely eliminate these bearing currents that cause damage stress to the bearings, and thus it is not possible to completely prevent electrolytic corrosion of the bearings due to aging.

In the case of the mold motor 119 of Patent Document 3, since it is necessary to apply the conductive paint to the inner peripheral surface of the motor frame with a uniform thickness, it is necessary to use an air brush for applying the conductive paint. After applying the entire side surface of the motor frame 125 with the mask processing to the outer peripheral surface with a conductive paint using an air brush, a process such as removing the mask attached to the outer peripheral surface is necessary. It was necessary to spend man-hours and costs for the mask removal process.
JP 2004-242413 A JP 2000-270507 A (pages 2 to 6) JP 2007-89338 A (page 6, FIG. 1)

  As described above, in a conventional molded motor that does not have a function to prevent galvanic corrosion due to bearing current, the bearing current in the discharge mode, which has a large damage stress on the bearing generated when the bearing is in a fluid lubrication state, and the bearing The frequency of occurrence in the boundary lubrication state is high, because the bearing current in the conductive mode that can not ignore the damage stress on the bearing is generated, and the bearing current that gives damage stress to these bearings cannot be completely eliminated, There is a problem that electric corrosion will occur sometime in bearings that continue to give damage stress due to bearing current, and it is possible to completely eliminate these bearing currents and prevent electric corrosion completely. Mold mode with a structure with functions It is required to provide.

  Also, as a function to prevent galvanic corrosion due to bearing current, even in a conventional molded motor in which two brackets are short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent galvanic corrosion, it occurs when the bearing is in a fluid lubrication state. These bearings generate discharge current bearing currents with high damage stress on the bearings and conductive currents that occur frequently when the bearings are in the boundary lubrication state, and the damage stress on the bearings cannot be ignored. Since the bearing current that gives damage stress cannot be completely eliminated, there is a problem that electric corrosion will occur in the bearing that continues to give damage stress due to the bearing current, and these bearing currents will disappear completely. Let it eat completely It is required to provide a molded motor having a structure with a possible electrolytic corrosion prevention features be stopped.

  In addition, as a function to prevent electrolytic corrosion due to bearing current, a conventional molded motor that has two brackets short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent electrolytic corrosion has a gap between the rotor and the motor frame. Since it must be designed to be within a range of 0.35 to 0.5 mm, a conductive paint is applied so that a conductive layer having a certain thickness or less is formed on the inner peripheral surface of the motor frame with a uniform thickness. Therefore, it is effective to apply an airbrush to apply conductive paint. However, when applying conductive paint to the motor frame using an airbrush, a motor frame with a mask treatment applied to the outer peripheral surface. After applying the entire side with conductive paint using an air brush, a process such as removing the mask attached to the outer peripheral surface is required. There is a problem that man-hours and costs are required for the process of removing the disc, and it is required to provide a mold motor having a structure with an electric corrosion countermeasure function that can eliminate the man-hours and costs for these mask processes. Yes.

  The present invention solves such a conventional problem, completely eliminates the bearing current that causes damage stress to the bearing and completely prevents the electrolytic corrosion of the bearing, and uses an air brush. An object of the present invention is to provide a mold motor having a structure with an anti-corrosion countermeasure function that eliminates the man-hours and costs required for the mask processing step that is required when forming a conductive layer with a conductive paint and reduces man-hours. It is said.

  In order to achieve the above object, the molded motor of the present invention provides a motor frame by integrally molding a stator, in which a coil is wound around a resin-insulated stator core, with a mold resin, and rotates the rotor. Of the two bearings attached to both ends of the rotating shaft of the rotor for free holding, one bearing is held by a metal bracket fitted to the motor frame, and the other bearing is held by the motor frame. In the inner rotor type molded motor that is held inside the motor frame, the motor frame is arranged such that the exposed portion of the stator core end surface is not formed on the inner peripheral surface of the motor frame facing the rotor. A resin portion to be covered; a first conductive layer formed on the entire inner peripheral surface of the motor frame; and an entire surface of the outer peripheral surface of the motor frame. A second conductive layer, and a connecting means for electrically connecting the stator core to the first conductive layer or the second conductive layer, and the stator to the first conductive layer. The molded motor is characterized in that the coil and the rotor are electrostatically shielded by being surrounded by the second conductive layer and completely sealed.

  By this means, the bearing current that causes damage stress to the bearing can be completely eliminated and the electrolytic corrosion of the bearing can be completely prevented, and it is necessary to apply it when the conductive layer is formed with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure equipped with an anti-corrosion countermeasure function that eliminates the man-hours and costs required for the mask processing step and reduces the man-hours.

  In order to achieve the above object, the molded motor of the present invention is provided with a motor frame by integrally molding a stator, in which a coil is wound around a stator iron core insulated with resin, with a mold resin, and a rotor. The two bearings attached to both ends of the rotor's rotating shaft are held by two brackets fitted in the openings on the output side and the non-output side of the motor frame, respectively. In the inner rotor type molded motor, the motor frame includes a resin portion that covers the stator so that the exposed portion of the stator core end surface is not formed on the inner peripheral surface of the motor frame facing the rotor. The first conductive layer formed on the entire inner peripheral surface of the motor frame, the second conductive layer formed on the entire outer peripheral surface of the motor frame, and the fixed A connecting means for electrically connecting the iron core and the first conductive layer or the second conductive layer, and the stator is surrounded by the first conductive layer and the second conductive layer to be completely sealed; The molded motor is characterized by electrostatically shielding the coil and the rotor in a state.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  Further, in order to achieve the above object, the molded motor of the present invention has a structure in which the core connecting terminal is contact-fixed or welded to the outer peripheral portion of the stator core to be conducted to the stator core, and then the motor frame molded integrally with the mold is used. On the outer peripheral side surface, the stator is covered with mold resin so that an exposed portion is formed on the end surface of the core connection terminal, the motor frame is formed, and the end portion of the core connection terminal is electrically connected to the exposed portion. And a connecting means configured to electrically connect the stator core and the second conductive layer by forming a second conductive layer on the entire outer peripheral surface of the motor frame. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is a motor frame in which an iron core connection terminal is contact-fixed or welded to the inner peripheral portion of the stator core to conduct to the stator core, and then molded integrally with the mold. The stator is covered with a mold resin so that an exposed portion is formed on the end surface of the core connection terminal on the inner peripheral surface of the motor frame, and the motor frame is formed, and is electrically connected to the exposed portion of the end surface of the core connection terminal And connecting means for electrically connecting the stator core and the first conductive layer by forming the first conductive layer on the entire inner peripheral surface of the motor frame. The molded motor according to claim 1 or 2, wherein

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the second conductive layer is a conductive layer formed by applying the entire outer peripheral surface of the motor frame with a conductive paint. Item 1 or 2 is a molded motor.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a transparent conductive paint. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the second conductive layer is a conductive layer formed by coating the entire outer peripheral surface of the motor frame with a transparent conductive paint. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a metal foil. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the second conductive layer is a conductive layer formed so as to cover the entire outer peripheral surface of the motor frame with a metal foil. A molded motor according to claim 1 or claim 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In the molded motor of the present invention, in order to achieve the above object, the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a metal solid. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  In order to achieve the above object, the molded motor of the present invention is characterized in that the second conductive layer is a conductive layer formed so as to cover the entire outer peripheral surface of the motor frame with a metal solid. The molded motor according to claim 1 or 2.

  This completely eliminates the bearing current that causes damage stress to the bearing and completely prevents galvanic corrosion of the bearing, and it is necessary to apply it when forming a conductive layer with conductive paint using an airbrush. Thus, it is possible to provide a mold motor having a structure having an electric corrosion countermeasure function that eliminates the man-hours and costs involved in the mask processing step and reduces the man-hours and is inexpensive.

  According to the present invention, it is possible to provide a molded motor having a structure equipped with an electric corrosion countermeasure function capable of completely eliminating a bearing current that causes damage stress to the bearing and completely preventing electric corrosion of the bearing. it can.

  In addition, the mold motor has a structure with a low-cost and anti-corrosion function that eliminates the man-hours and costs involved in the mask processing process that had to be performed when forming a conductive layer with a conductive paint using an air brush. Can be provided.

  According to a first aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, the second conductive layer is formed on the entire outer peripheral surface of the motor frame, By having a connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, the coil and the stator core are surrounded by the first conductive layer and the second conductive layer. In this completely sealed state, the coil and the rotor are electrostatically shielded. With these configurations, the electrostatic coupling capacity between the coil and the rotor and the electrostatic coupling capacity between the coil and the bracket are eliminated, and the rotor A common mode equivalent circuit is formed in which the electrostatic coupling capacity between the rotor and the bracket is connected in parallel with the electrostatic coupling capacity between the rotor and the stator core, so that the bearing is fluid lubricated like a conventional molded motor. When it becomes a state In addition, the closed circuit that existed in the conventional molded motor that transmits the voltage applied between the coil and the ground as a voltage generated in the parasitic capacitance between the inner ring and the outer ring of the bearing is not formed, and the bearing is fluid lubricated. In this state, no voltage is generated in the parasitic capacitance between the inner ring and the outer ring of the bearing as a response voltage for the common mode voltage supplied from the inverter device, so the parasitic capacitance connected in parallel between the inner ring and the outer ring is reduced. It has the effect that the discharge mode bearing current generated as a discharge phenomenon of the accumulated inner ring-outer ring voltage can be completely extinguished.

  According to a first aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and the rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, the electrostatic coupling capacity between the coil and the rotor and the electrostatic coupling capacity between the coil and the bracket are made zero, A common mode equivalent circuit is formed to connect the capacitive coupling capacity between the rotor and the bracket in parallel to the capacitive coupling capacity between the rotor and the stator core. If When the closed circuit that existed in the conventional molded motor that transmits the voltage applied between the bearing and the ground as current flowing between the inner ring and the outer ring of the bearing is not formed, and the bearing is in a boundary lubrication state, As a response current with respect to the common mode voltage supplied from the inverter device, there is an effect that the conductive current of the conductive mode flowing between the inner ring and the outer ring of the bearing can be completely extinguished.

  According to a first aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and the rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, the bearing current in the discharge mode and the damage stress that cause a large damage stress to the bearing as described above are as follows. It is not as large as the discharge mode bearing current, but the frequency of occurrence is high, and the damage current on the bearing cannot be ignored. It can disappear 璧 has an effect that it is possible to perfectly eliminate electrolytic corrosion of the bearing due to these bearing current.

  According to a first aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, a conductive layer is formed by applying conductive paint to the entire side of the motor frame using an air brush. By simply applying conductive paint to the entire side of the motor frame using an air brush, the man-hours required for masking the outer peripheral surface of the motor frame, which was necessary with conventional mold motors, can be eliminated. To.

  According to a second aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and the rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, the electrostatic coupling capacity between the coil and the rotor and the electrostatic coupling capacity between the coil and the bracket are extinguished, A common mode equivalent circuit is formed in which the electrostatic coupling capacitance between the rotor and the bracket is connected in parallel to the electrostatic coupling capacitance between the rotor and the stator core. With fluid lubrication In this case, the closed circuit existing in the conventional molded motor that transmits the voltage applied between the coil and the ground as the voltage generated in the parasitic capacitance between the inner ring and the outer ring of the bearing is not formed, and the bearing is not formed. In the fluid lubrication state, no voltage is generated in the parasitic capacitance between the inner ring and the outer ring of the bearing as a response voltage for the common mode voltage supplied from the inverter, so a parasitic connected in parallel between the inner ring and the outer ring. It has an effect that the discharge mode bearing current generated as a discharge phenomenon of the inner ring-outer ring voltage accumulated in the capacity can be completely extinguished.

  According to a second aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and the rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, the electrostatic coupling capacity between the coil and the rotor and the electrostatic coupling capacity between the coil and the bracket are extinguished, A common mode equivalent circuit is formed in which the electrostatic coupling capacitance between the rotor and the bracket is connected in parallel to the electrostatic coupling capacitance between the rotor and the stator core. Boundary lubrication and In this case, the closed circuit that existed in the conventional molded motor that transmits the voltage applied between the coil and the ground as the current flowing between the inner ring and the outer ring of the bearing is not formed, and the bearing is in a boundary lubrication state. In this case, as a response voltage to the common mode voltage supplied from the inverter device, the conductive mode bearing current flowing between the inner ring and the outer ring of the bearing can be completely extinguished.

  According to a second aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and the rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, the bearing current in the discharge mode and the damage stress that cause a large damage stress to the bearing as described above are as follows. It is not as large as the discharge mode bearing current, but it occurs frequently and completes both of the conductive mode bearing currents where damage stress on the bearing cannot be ignored. Can disappear, it has an effect that it is possible to perfectly eliminate electrolytic corrosion of the bearing due to these bearing current.

  According to a second aspect of the present invention, the first conductive layer is formed on the entire inner peripheral surface of the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame. And connecting means for electrically connecting the stator core and the first conductive layer or the second conductive layer, whereby the coil and the stator core are connected to the first conductive layer and the second conductive layer. The coil and rotor are electrostatically shielded by enclosing them in a completely sealed state. With these configurations, a conductive layer is formed by applying conductive paint to the entire side of the motor frame using an air brush. By simply applying conductive paint to the entire side of the motor frame using an air brush, the man-hours required for masking the outer peripheral surface of the motor frame, which was necessary with conventional mold motors, can be eliminated. To.

  According to a third aspect of the present invention, the iron core connection terminal is contact-fixed or welded to the outer peripheral portion of the stator core to conduct to the stator core, and then the iron core connection terminal is provided on the outer peripheral surface of the motor frame. A mold resin portion is formed to cover the stator so that the exposed portion is formed, and the second conductive layer is formed on the outer peripheral surface of the motor frame so as to be electrically connected to the exposed portion of the iron core connection terminal. The stator core and the second conductive layer are electrically connected. With these configurations, the core connection terminals are fixed in contact or welded between the laminated plates constituting the stator core. Since a current loop linked to the rotating magnetic field is not formed between adjacent laminated plates via a conductor such as an iron core connection terminal, the stator is driven by the rotating magnetic field. The outer circumference of the iron core Even if the magnetic flux changes in the direction toward the center, there is no current loop linked to the magnetic flux between the adjacent laminated plates, so an eddy current flowing between the adjacent laminated plates is generated due to the change in the magnetic flux. Therefore, the iron loss due to the generation of eddy current can be minimized.

  In the invention according to claim 4 of the present invention, the iron core connection terminal is contact-fixed or welded to the inner peripheral portion of the stator core to conduct with the stator core, and then the iron core is attached to the inner peripheral surface of the motor frame. A mold resin portion covering the stator is formed so that the exposed portion of the connection terminal is formed, and a first conductive layer is formed on the inner peripheral surface of the motor frame so as to be electrically connected to the exposed portion of the iron core connection terminal. Thus, the stator core and the first conductive layer are electrically connected to each other. With these configurations, the core connection terminals are contact-fixed or welded between the laminated plates constituting the stator core. A current loop that is connected to the rotating magnetic field is not formed between adjacent laminated plates via a conductor such as an iron core connection terminal, so that the rotating magnetic field is formed. Depending on the outer circumference of the stator core Even if the magnetic flux changes in the direction toward the center, there is no current loop linked to the magnetic flux between the adjacent laminated plates, so an eddy current flowing between the adjacent laminated plates is generated due to the change in the magnetic flux. Therefore, the iron loss due to the generation of eddy current can be minimized.

  According to a fifth aspect of the present invention, the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint. The conductive layer can be quickly formed on the entire inner peripheral surface of the motor frame described in 2 by an easy process.

  According to a sixth aspect of the present invention, the second conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint. The conductive layer can be quickly formed on the entire inner peripheral surface of the motor frame described in 2 by an easy process.

  According to a seventh aspect of the present invention, the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a transparent conductive paint. In addition to being able to quickly form a conductive layer on the entire inner peripheral surface of the motor frame described in 2 by an easy process, there is an effect that there is no sense of discomfort in the appearance of the conductive paint.

  According to an eighth aspect of the present invention, the second conductive layer is a conductive layer formed by applying the entire outer peripheral surface of the motor frame with a transparent conductive paint. In addition to forming the conductive layer quickly on the entire outer peripheral surface of the motor frame described in the above, it has the effect of eliminating a sense of discomfort in the appearance of the conductive paint.

  According to a ninth aspect of the present invention, the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a metal foil. 2 has an effect that a conductive layer having a uniform thickness can be reliably formed on the entire inner peripheral surface of the motor frame.

  According to a tenth aspect of the present invention, the second conductive layer is a conductive layer formed so as to cover the entire outer peripheral surface of the motor frame with a metal foil. The conductive layer having a uniform thickness can be reliably formed on the entire inner peripheral surface of the motor frame described in (1).

  According to an eleventh aspect of the present invention, the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a solid metal. 2 has an effect that a conductive layer having a uniform thickness can be rapidly formed on the entire inner peripheral surface of the motor frame.

  According to a twelfth aspect of the present invention, the second conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a solid metal. 2 has an effect that a conductive layer having a uniform thickness can be rapidly formed on the entire inner peripheral surface of the motor frame.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a structural sectional view for explaining the structure of the molded motor according to the first embodiment of the present invention. As shown in the figure, a molded motor 1 is a brushless DC motor, and an insulating layer 3 is formed on a stator core 2 in which laminated plates made by processing a ferromagnetic material such as a silicon steel plate are laminated. A coil 4 is wound around the stator core 2 via 3. The stator core 2, the insulating layer 3, the coil 4, and a part of the coil 4, and the stator 6 formed of the coil end portion 5 where the coil 4 protrudes from the stator core 2, for example, epoxy resin, or A substantially cylindrical motor frame 8 is formed by covering with a mold resin 7 such as an unsaturated polyester resin. A rotor 9 is inserted inside the motor frame 8 through a gap, and is fixed so that the exposed portion of the stator core end face 40 is not formed on the inner peripheral surface 10 of the motor frame 8 facing the rotor 9. A motor frame 8 is formed by covering the child 6 with a mold resin 7. A donut-shaped wiring board 11 is attached to the opening output side of the motor frame 8 as shown. Since the mold motor 1 is a brushless DC motor, an inverter device that drives the mold motor 1 by PWM control is incorporated in the wiring board 11. A metal bracket 12 is embedded in the motor frame 8 on the output side end face of the motor frame 8. Two bearings 14 to 15 are attached to both sides of the rotary shaft 13 attached to the center of the rotor 9. The two bearings 14 to 15 are respectively held by the bracket 12 and the mold resin 7 of the motor frame 8 as illustrated. The rotor 9 can rotate with the rotating shaft 13 supported by two bearings 14 to 15. A first conductive layer 16 coated with a conductive paint such as silver paint is formed on the entire inner peripheral surface 10 of the motor frame 8. A second conductive layer 18 coated with a conductive paint such as silver paint is formed on the entire outer peripheral surface 17 of the motor frame 8. Here, the stator core 2 is connected so as to be electrically connected to the second conductive layer 18 by connection means 19 described later, which is illustrated by a portion surrounded by a dotted line. With the first conductive layer 16 and the second conductive layer 18, the conductive paint is applied to the entire surface of the motor frame 8, and the stator core 2 around which the coil 4 is wound is the first conductive layer. Since the coil 4 is completely sealed by the first conductive layer 16 and the second conductive layer 18, the coil 4 is completely electrostatically shielded from the rotor 9 by the first conductive layer 16 and the second conductive layer 18.

  FIG. 2 is an enlarged view of the connecting means 19 shown in FIG. As shown in the figure, the iron core connection terminal 20 is fixed to the outer peripheral portion 21 of the stator iron core 2 by welding. When the stator 6 is covered with the mold resin 7 and the motor frame 8 is formed, the motor frame 8 is formed such that the exposed portion 23 of the end face 22 of the core connection terminal 20 is formed. A second conductive layer 18 is formed by applying a conductive paint such as silver paint over the entire outer peripheral surface 17 of the motor frame 8 including the exposed portion 23 of the end face 22 of the iron core connection terminal 20. Since the core connection terminal 20 is electrically connected to the second conductive layer 18 via the exposed portion 23 of the end face 22, the stator core 2 is connected to the second conductive layer 18 via the core connection terminal 20. Will be conducted.

  FIG. 3 is a side view of the stator around the connecting means 19 as viewed from the direction A shown in FIG. As shown in the figure, the stator core 2 is formed by insulating and laminating laminated plates 24a to 24e processed with a ferromagnetic material such as a silicon steel plate through an insulating resin. As described above, the core connection terminal 20 is welded and fixed to the outer peripheral portion 21 of the stator core 2, and the core connection terminal 20 is welded between adjacent laminated plates, for example, the laminated plate 24a and the laminated plate 24b. Since conduction is made only through the portions and other portions are insulated through the insulating resin, a current loop passing through the adjacent laminated plates 24a and 24b is not formed. Similarly, a current loop passing through the adjacent laminated plates is not formed for other adjacent laminated plates other than the laminated plates 24a and 24b. Even if the rotating magnetic field generates a magnetic flux that changes in the direction B shown in the figure, that is, from the back to the front of the paper, there is no current loop interlinking with the magnetic flux between adjacent laminated plates. Due to the change in magnetic flux, eddy current flowing between adjacent laminated plates is not generated, and iron loss due to generation of eddy current can be minimized.

  FIG. 4 is a model diagram showing a distribution state of electrostatic coupling capacitance between each part of the molded motor according to the first embodiment. In FIG. 4, since the coil 4 is wound around the stator core 2 made of a ferromagnetic material, a relatively large equivalent inductance Lc exists. Since the coil 4 is disposed at a position close to the stator core 2 with the insulating layer 3 interposed therebetween, a relatively large electrostatic capacitance is provided between the coil 4 and the stator core 2 along the winding direction of the coil 4. There is a coupling capacitance Ccs. Since the molded motor 1 is a brushless DC motor, the gap between the inner peripheral surface 10 of the motor frame 8 and the rotor 9 is generally designed to be narrow so as to be within a range of 0.35 to 0.5 mm, for example. Therefore, a relatively large air gap capacity Crs also exists between the stator core 2 and the rotor 9. An electrostatic coupling capacitance Cbr exists between the bracket 12 and the rotor 9. Between the inner ring and the outer ring of the bearing 14, there is an electrostatic coupling capacitance Cb1 between the inner ring and the outer ring with the rolling element interposed therebetween. Further, an electrostatic coupling capacitance Cs exists between the bracket 12 and the ground. The coil 4 is completely sealed by the first conductive layer 16 and the second conductive layer 18 that are electrically connected to the stator core 2 via the iron core connection terminal 20, that is, sealed without leakage. The electrostatic coupling capacitance Ccr between the coil 104 and the rotor 109, which is completely electrostatically shielded from the rotor 9 by the layer 16 and the second conductive layer 18 and exists in the conventional mold motor 101, is shown in the first embodiment. This mold motor 1 no longer exists. Further, the electrostatic coupling capacitance Cbc between the bracket 12 and the coil 4 existing in the conventional molded motor 101 is such that the bracket 12 passes through the second conductive layer 18 and the iron core connection terminal 20 as shown in the figure. Since it is electrically connected to the stator core 2, the circuit configuration is connected in parallel to the electrostatic coupling capacitance Ccs between the coil 4 and the stator core 2, and becomes a part of the electrostatic coupling capacitance Ccs.

  FIG. 5 is a common mode equivalent circuit for explaining waveforms of respective parts of the molded motor when the bearing of the molded motor according to the first embodiment is in a fluid lubrication state. As shown in the drawing, the common mode equivalent circuit 25 configured by the equivalent inductance Lc and the electrostatic coupling capacitors Ccs, Crs, Cbr, Cs, Cb1, and Cs described with reference to FIG. 4 is formed. The major difference when compared with the common mode equivalent circuit of the conventional mold motor 101 is that the electrostatic coupling capacitance Ccr between the coil 4 and the rotor 9 existing in the conventional mold motor 101 is the first. Since the rotor 9 is electrostatically shielded in a configuration completely sealed by the conductive layer and the second conductive layer, the electrostatic coupling capacitance Ccr is zero.

  Furthermore, the electrostatic coupling capacitance Cbc between the bracket 12 and the coil 4 becomes a part of the electrostatic capacitance Ccs between the coil 4 and the stator core 2 because the bracket 12 is electrically connected to the stator core 2. There is no electrostatic coupling capacitance between the bracket 12 and the coil 4 here. Furthermore, the electrostatic coupling capacitance Cbr between the bracket 12 and the stator core 2 has a circuit configuration connected in parallel to the electrostatic coupling capacitance Crs between the rotor 9 and the stator core 2. Between the inner ring and the outer ring of the bearing 14, there is a parasitic capacitance in which electrostatic coupling capacitances Crs, Cbr and Cb1 are connected in parallel.

  As is clear from the common mode equivalent circuit 25 shown in FIG. 5, even if the common mode voltage 26 supplied from the inverter device of the wiring board 11 is applied to the coil 4, the mold motor 1 of the first embodiment Since the electrostatic coupling capacitance Ccr disappears, the closed circuit 117 or the closed circuit 134 as formed in the conventional mold motor 101 or the mold motor 119 is not formed, and the common mode equivalent circuit 25 with respect to the common mode voltage 26 is not formed. As the response voltage, the parasitic capacitance (that is, Crs, Cbr, and the like) existing between the inner ring and the outer ring of the bearing 14 or the bearing 15 in the fluid lubrication state as generated in the conventional molded motor 101 or the molded motor 119 is used. No voltage is transmitted to (capacitance with Cb1 connected in parallel)

  FIG. 6 is a time chart of each part for explaining that a discharge mode bearing current is not generated when the bearing of the molded motor according to the first embodiment is in a fluid lubrication state. As is apparent from the configuration of the common mode equivalent circuit 25 described with reference to FIG. 5, even if a common mode voltage 26 as illustrated is applied between the coil 4 and the ground from the inverter device incorporated in the wiring board 11, As a response voltage of the common mode equivalent circuit 25 with respect to the mode voltage 26, the voltage is charged to the parasitic capacitance between the inner ring and the outer ring of the bearing 14 in the fluid lubrication state (that is, the capacitance in which Crs, Cbr, and Cb1 are connected in parallel). Therefore, as shown in the figure, no discharge mode bearing current is generated as a discharge phenomenon of the parasitic capacitance.

  FIG. 7 is a common mode equivalent circuit for explaining waveforms of respective parts of the molded motor when the bearing of the molded motor according to the first embodiment is in the boundary lubrication state. The difference from the common mode equivalent circuit when the bearing described in FIG. 5 is in a fluid lubrication state is that the bearing 14 to the bearing 15 are always in conduction, and the switch, which is an electrical expression of the bearing 14 to the bearing 15, is closed. It is in a state. As shown in the drawing, the common mode equivalent circuit 27 constituted by the equivalent inductance Lc and the electrostatic coupling capacitors Ccs, Crs, Cbr, Cb1, and Cs described in FIG. 2 is formed. As apparent from the common mode equivalent circuit 27 shown in FIG. 7, even if the common mode voltage 26 supplied from the inverter device of the wiring board 11 is applied to the coil 4, the molded motor 1 of the first embodiment has a static Since the electric coupling capacitance Ccr disappears, the closed circuit 118 or the closed circuit 135 as formed in the conventional molded motor 101 or the molded motor 119 is not formed, and the response of the common mode equivalent circuit 27 to the common mode voltage 26 is eliminated. As a current, a conductive current in the conductive mode that is transmitted to the bearing 14 in the boundary lubrication state as generated in the conventional mold motor 101 or the mold motor 119 is not generated.

  FIG. 8 is a time chart of each part for explaining that the bearing current in the conductive mode is not generated when the bearing of the molded motor according to the first embodiment is in the boundary lubrication state. When the mold motor 1 rotates at a low speed and the bearing 14 is in the boundary lubrication state, even if a common mode voltage 26 as illustrated is applied between the coil 4 and the ground from the inverter device incorporated in the wiring board 11, As a response current of the common mode equivalent circuit 27 with respect to the common mode voltage 26, no conductive current is generated in the boundary lubricated bearing 14.

  As described above, in the molded motor according to the first embodiment, the bearing current in the discharge mode having a large damage stress applied to the bearing and the damage stress are not as large as the bearing current in the discharge mode, but the occurrence frequency is high. It is possible to completely eliminate both of the conductive mode bearing currents in which the damaging stress is not negligible, and to completely eliminate the electrolytic corrosion of the bearings caused by these bearing currents.

  Further, in a conventional molded motor in which two conventional brackets as described in Document 4 are short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent galvanic corrosion, a uniform thickness is applied only to the inner peripheral surface of the motor frame. Since it is necessary to apply conductive paint, it is necessary to use an air brush to apply the conductive paint, but apply the entire side of the motor frame with the mask treatment on the outer peripheral surface with the conductive paint using the air brush. After that, a process such as removing the mask attached to the outer peripheral surface is necessary, and there is a problem that man-hours and costs are required for the mask attaching process and the mask removing process after applying the conductive paint. However, in the case of the mold motor according to the first embodiment, since the conductive paint is applied to the entire surface of the motor frame, the man-hours required for the mask processing are eliminated. The molded motor structure with Kill electrolytic corrosion prevention features may be an effect that can be achieved at low cost.

(Embodiment 2)
FIG. 9 is a structural cross-sectional view for explaining the structure of the molded motor according to the second embodiment of the present invention. The same reference numerals are used for the same portions as those in the first embodiment, and the description of the configuration is omitted. In FIG. 9, the stator core 2 of the molded motor 28 and the first conductive layer 16 are connected to each other by connection means 29 described later, which is illustrated by a portion surrounded by a dotted line.

  FIG. 10 is an enlarged view of the connecting means 29 shown in FIG. As shown in the figure, the core connection terminal 30 is welded and fixed to the inner peripheral portion 31 of the stator core 2. When the motor frame 8 is formed by covering the stator 6 with the mold resin 7, the motor frame 8 is formed such that the exposed portion 33 is formed on the end surface 32 of the iron core connection terminal 30. A first conductive layer 16 is formed by applying a conductive paint such as silver paint over the entire inner peripheral surface 10 of the motor frame 8 including the exposed portion 33 of the end face 32 of the core connection terminal 30. Since the core connection terminal 30 is electrically connected to the first conductive layer 16 via the exposed portion 33 of the end face 32, the stator core 2 is connected to the first conductive layer 16 via the core connection terminal 30. Will be conducted.

  FIG. 11 is a side view of the stator around the connection means 29 viewed from the direction C shown in FIG. As shown in the figure, the stator core 2 is formed by insulating and laminating laminated plates 34a to 34e processed with a ferromagnetic material such as a silicon steel plate through an insulating resin. As described above, the core connection terminal 30 is welded and fixed to the inner peripheral portion 31 of the stator core 2, and the core connection terminal 30 is welded between adjacent laminated plates, for example, the laminated plate 34a and the laminated plate 34b. Since the other portions are insulated through the insulating resin, the current loop passing through the adjacent laminated plates 34a and 34b is not formed. Similarly, a current loop passing through the adjacent laminated plates is not formed for other adjacent laminated plates other than the laminated plates 34a and 34b. Even if the rotating magnetic field generates a magnetic flux that changes in the direction B shown in the figure, that is, from the back to the front of the paper, there is no current loop interlinking with the magnetic flux between adjacent laminated plates. Due to the change in magnetic flux, eddy current flowing between adjacent laminated plates is not generated, and iron loss due to generation of eddy current can be minimized.

  As described above, the difference between the second embodiment and the first embodiment is that, in the molded motor 1 of the first embodiment, the core connecting terminal attached to the outer peripheral portion 21 of the stator core 2 by the connecting means 19. 20, the stator core 2 and the second conductive layer 18 are electrically connected to each other, whereas the molded motor 28 according to the second embodiment is attached to the stator core 2 by the connecting means 29. The stator core 2 and the first conductive layer 16 are electrically connected to each other via the iron core connection terminal 30, and the stator core 2 is electrically connected to the first conductive layer or the second conductive layer. With respect to other configurations only, the second embodiment is the same as the first embodiment, and the second embodiment can achieve the same effects as the first embodiment.

  As described above, even in the molded motor of the second embodiment, the bearing current in the discharge mode, which has a large damage stress on the bearing, and the damage stress are not as large as the bearing current in the discharge mode, but the occurrence frequency is high. It is possible to completely eliminate both of the conductive mode bearing currents in which the damaging stress is not negligible, and to completely eliminate the electrolytic corrosion of the bearings caused by these bearing currents.

  Further, in a conventional molded motor in which two conventional brackets as described in Document 4 are short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent electrolytic corrosion, a uniform thickness is provided on the inner peripheral surface of the motor frame. Because it is necessary to apply conductive paint with the air brush, it is necessary to use an air brush to apply the conductive paint. However, the entire side of the motor frame with the mask treatment applied to the outer peripheral surface was applied with the conductive paint using the air brush. After that, a process such as removing the mask attached to the outer peripheral surface is necessary, and there was a problem that man-hours and costs were required for the mask attaching process and the mask removing process after applying the conductive paint. In the case of the mold motor according to the third embodiment, since the conductive paint is applied to the entire surface of the motor frame, the man-hours required for mask processing can be eliminated. It can be an effect that a molded motor structure having electrical corrosion prevention features can be realized at low cost.

(Embodiment 3)
FIG. 12 is a structural cross-sectional view for explaining the structure of the molded motor according to the third embodiment of the present invention. In FIG. 7, the same reference numerals are used for the same portions as those in Embodiment 1 of the embodiment, and the description of the configuration is omitted.

  As shown in the figure, in the molded motor 35, a metal bracket 12 is embedded in the motor frame 8 on the output side end surface of the motor frame 8, and further, the metal frame 12 is made of metal on the counter output side end surface of the motor frame 8. The bracket 36 is embedded in the motor frame 8. Two bearings 14 to 15 are attached to both sides of the rotary shaft 13 attached to the center of the rotor 9. The two bearings 14 and 15 are respectively held by the bracket 12 and the bracket 36 as shown in the figure. The rotor 9 can rotate with a rotating shaft 13 supported by two bearings 14 and 15.

  A first conductive layer 16 coated with a conductive paint such as silver paint is formed on the entire inner peripheral surface 10 of the motor frame 8. A second conductive layer 18 applied with a conductive paint such as silver paint is formed on the entire outer peripheral surface 17 of the motor frame 8. Here, the stator core 2 and the second conductive layer 18 are connected so as to be conducted by the connecting means 19 illustrated in FIGS. 2 to 3 of the first embodiment, which is illustrated by a portion surrounded by a dotted line. Yes. With the first conductive layer 16 and the second conductive layer 18, the conductive paint is applied to the entire surface of the motor frame 8, and the stator core 2 around which the coil 4 is wound is the first conductive layer. Since the coil 4 is completely sealed by the first conductive layer 16 and the second conductive layer 18, the coil 4 is completely electrostatically shielded from the rotor 9 by the first conductive layer 16 and the second conductive layer 18.

  FIG. 13 is a model diagram illustrating a distribution state of the electrostatic coupling capacitance between each part of the molded motor according to the third embodiment. As shown in the figure, since the coil 4 is wound around the stator core 2 that is a ferromagnetic body, a relatively large equivalent inductance Lc exists. Since the coil 4 is disposed at a position close to the stator core 2 with the insulating layer 3 interposed therebetween, a relatively large electrostatic capacitance is provided between the coil 4 and the stator core 2 along the winding direction of the coil 4. There is a coupling capacitance Ccs. Since the mold motor 35 is a brushless DC motor, generally, the gap between the inner peripheral surface 10 of the motor frame 8 and the rotor 9 is narrow so as to be within a range of 0.35 to 0.5 mm, for example. Since it is designed, a relatively large air gap capacity Crs also exists between the stator core 2 and the rotor 9. An electrostatic coupling capacitance Cbr1 exists between the bracket 12 and the rotor 9. An electrostatic coupling capacitance Cbr2 also exists between the bracket 36 and the rotor 9. Between the inner ring and the outer ring of the bearing 14, there is an electrostatic coupling capacitance Cb1 between the inner ring and the outer ring with the rolling element interposed therebetween. An electrostatic coupling capacitance Cb2 between the inner ring and the outer ring exists between the inner ring and the outer ring of the bearing 15 with the rolling elements interposed therebetween. Further, an electrostatic coupling capacitance Cs exists between the bracket 12 and the bracket 36 and the ground. The coil 4 is completely sealed by the first conductive layer 16 and the second conductive layer 18 that are electrically connected to the stator core 2 via the iron core connection terminal 20, that is, sealed without leakage. The electrostatic coupling capacitance Ccr between the coil 104 and the rotor 109 that is completely electrostatically shielded from the rotor 9 by the layer 16 and the second conductive layer 18 and exists in the conventional mold motor 101 is shown in the third embodiment. The mold motor 35 no longer exists. The electrostatic coupling capacitance Cbc1 between the bracket 12 and the coil 4 existing in the conventional molded motor 101 is such that the bracket 12 is connected to the stator via the second conductive layer 18 and the core connection terminal 20 as shown in the figure. Since it is electrically connected to the iron core 2, it becomes a circuit configuration connected in parallel to the electrostatic coupling capacitance Ccs between the coil 4 and the stator iron core 2, and becomes a part of the electrostatic coupling capacitance Ccs. Furthermore, the electrostatic coupling capacitance Cbc2 between the bracket 12 and the coil 4 existing in the conventional molded motor 101 is also connected to the bracket 12 via the second conductive layer 18 and the iron core connection terminal 20, as shown in the figure. Since it is electrically connected to the stator core 2, the circuit configuration is connected in parallel to the electrostatic coupling capacitance Ccs between the coil 4 and the stator core 2, and becomes a part of the electrostatic coupling capacitance Ccs.

  FIG. 14 is a common mode equivalent circuit for explaining the waveforms of each part of the molded motor when the bearing of the molded motor according to the third embodiment is in a fluid lubrication state. The same portions as those in the common mode equivalent circuit 27 described in FIG. 5 of the first embodiment will be described using the same reference numerals. As shown in the figure, a common mode equivalent circuit 37 including an equivalent inductance Lc and electrostatic coupling capacitances Ccs, Crs, Cbr1, Cbr2, Cs, Cb1, and Cb2 is formed in the same manner as described with reference to FIG. The major difference when compared with the common mode equivalent circuit of the conventional mold motor 101 is that the electrostatic coupling capacitance Ccr between the coil 4 and the rotor 9 existing in the conventional mold motor is the same as that of the first coil 4. Since the rotor 9 is electrostatically shielded by a configuration completely sealed by the conductive layer 16 and the second conductive layer 18, the electrostatic coupling capacitance Ccr is zero. The electrostatic coupling capacitance Cbc1 between the bracket 12 and the coil 4 and the electrostatic coupling capacitance Cbc2 between the bracket 36 and the coil 4 are electrically connected to the stator core 2 because the bracket 12 or the bracket 36 is electrically connected. Since it becomes a part of the electrostatic coupling capacitance Ccs between the iron cores 2, it is not shown here. The electrostatic coupling capacitance Cbr1 between the bracket 12 and the stator core 2 and the electrostatic coupling capacitance Cbr2 between the bracket 36 and the stator core 2 are parallel to the electrostatic coupling capacitance Crs between the rotor 9 and the stator core 2. The circuit configuration is connected. Further, between the inner ring and the outer ring of the bearing 14, there is a parasitic capacitance obtained by connecting the electrostatic coupling capacitance Crs, the electrostatic coupling capacitance Cbr1, the electrostatic coupling capacitance Cbr2, the electrostatic parasitic capacitance Cb1, and the electrostatic coupling capacitance Cb2 in parallel. Exists.

  As is clear from the common mode equivalent circuit 37 shown in FIG. 14, even if the common mode voltage 26 supplied from the inverter device of the wiring board 11 is applied to the coil 4, the molded motor 35 of the second embodiment Since the electric coupling capacitance Ccr disappears, the closed circuit 117 or the closed circuit 134 as formed in the conventional molded motor 101 or the molded motor 119 is not formed, and the response of the common mode equivalent circuit 37 to the common mode voltage 26 is eliminated. As a voltage, a parasitic capacitance (that is, Crs, Cbr1, Cbr2, Cb1, and Cb2) existing between the inner ring and the outer ring of the bearing 14 in a fluid lubrication state as generated in the conventional molded motor 101 or the molded motor 119 is parallel. No voltage is transmitted to the connected capacitance.

  Next, when the bearing of the molded motor according to the second embodiment is in a fluid lubrication state, the fact that no discharge mode bearing current is generated will be described using the time chart illustrated in FIG. 6 described in the first embodiment. To do. As is clear from the configuration of the common mode equivalent circuit 37 described in FIG. 14, the common mode voltage 26 illustrated in FIG. 6 described in the first embodiment is applied to the coil 4 from the inverter device incorporated in the wiring board 11. As a response voltage of the common mode equivalent circuit 37 to the common mode voltage 26, the parasitic capacitance between the inner ring and the outer ring of the bearing 14 in the fluid lubrication state (that is, Crs, Cbr1, Cbr2, Cb1, and Since the voltage is not charged to the capacitance of Cb2 connected in parallel), as shown in FIG. 6 described in the first embodiment, a discharge mode bearing current generated as a discharge phenomenon of the parasitic capacitance is also generated. do not do.

  FIG. 15 is a common mode equivalent circuit for explaining the waveforms of the respective parts of the molded motor when the bearing of the molded motor according to the third embodiment is in the boundary lubrication state. The difference from the common mode equivalent circuit 37 when the bearing described in FIG. 14 is in a fluid lubrication state is that the bearing 14 to the bearing 15 are always conducting, and the switch that is an electrical expression of the bearing 14 to the bearing 15 is closed. It is in a state that has become. As shown in the drawing, the common mode equivalent circuit 38 composed of the equivalent inductance Lc, the electrostatic coupling capacitances Ccs, Crs, Cbr1, Cbr2, Cs, Cb1, and Cb2 described in FIG. 2 is formed.

  As is apparent from the common mode equivalent circuit 38 illustrated in FIG. 15, even if the common mode voltage 26 supplied from the inverter device of the wiring board 11 is applied to the coil 4, the molded motor 35 of the third embodiment Since the electrostatic coupling capacitance Ccr disappears, the closed circuit 118 or the closed circuit 135 as formed in the conventional mold motor 101 or the molded motor 119 is not formed, and the common mode equivalent circuit 38 with respect to the common mode voltage 26 is not formed. As a response current, a conductive current in the conductive mode transmitted to the bearing 14 or the bearing 15 in the boundary lubrication state as generated in the conventional molded motor 101 or the molded motor 119 is not generated.

  Next, the fact that the bearing current in the conductive mode is not generated when the bearing of the molded motor of the third embodiment is in the boundary lubrication state will be described using the time chart illustrated in FIG. 8 described in the first embodiment. To do. When the bearings 14 to 15 of the molded motor 35 are in the boundary lubrication state, the common mode voltage 26 as illustrated in FIG. 8 described in the first embodiment is applied to the coil 4 from the inverter device incorporated in the wiring board 11. As shown in FIG. 8 described in the first embodiment, the bearing 14 in the boundary lubrication state has a conductive mode bearing as a response current of the common mode equivalent circuit 38 with respect to the common mode voltage 26 even when applied to the ground. No current is generated.

  As described above, in the molded motor of the third embodiment, the bearing current in the discharge mode, which has a large damage stress on the bearing, and the damage stress are not as large as the bearing current in the discharge mode, but the occurrence frequency is high. It is possible to completely eliminate both of the conductive mode bearing currents in which the damaging stress is not negligible, and to completely eliminate the electrolytic corrosion of the bearings caused by these bearing currents.

  Further, in a conventional molded motor in which two conventional brackets as described in Document 4 are short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent electrolytic corrosion, a uniform thickness is provided on the inner peripheral surface of the motor frame. Because it is necessary to apply conductive paint with the air brush, it is necessary to use an air brush to apply the conductive paint. However, the entire side of the motor frame with the mask treatment applied to the outer peripheral surface was applied with the conductive paint using the air brush. After that, a process such as removing the mask attached to the outer peripheral surface is necessary, and there was a problem that man-hours and costs were required for the mask attaching process and the mask removing process after applying the conductive paint. In the case of the mold motor according to the third embodiment, since the conductive paint is applied to the entire surface of the motor frame, the man-hours required for mask processing can be eliminated. It can be an effect that a molded motor structure having electrical corrosion prevention features can be realized at low cost.

(Embodiment 4)
FIG. 16 is a structural cross-sectional view for explaining the structure of the molded motor according to the fourth embodiment of the present invention. The same reference numerals are used for the same portions as in the third embodiment, and the description of the configuration is omitted. In FIG. 16, the stator core 2 of the molded motor 39 and the first conductive layer 16 are made conductive by the connecting means 29 described in FIGS. 10 to 11 of the second embodiment, which is illustrated by a portion surrounded by a dotted line. So connected.

  The difference between the fourth embodiment and the third embodiment is that, in the molded motor 35 of the third embodiment, the stator 19 is connected to the outer peripheral portion 21 of the stator core 2 by the connecting means 19. In contrast to the structure in which the iron core 2 and the second conductive layer 18 are electrically connected, in the molded motor 39 of the fourth embodiment, the iron core attached to the inner peripheral portion 31 of the stator iron core 2 by the connecting means 29. This is a portion where the stator core 2 and the first conductive layer 16 are conducted through the connection terminal 30, and the configuration for conducting the stator core 2 to the first conductive layer or the second conductive layer is different. In other configurations, the fourth embodiment is the same as the third embodiment, and the fourth embodiment can obtain the same effects as the third embodiment.

  As described above, even in the molded motor according to the fourth embodiment, the bearing current in the discharge mode, which has a large damage stress on the bearing, and the damage stress are not as large as the bearing current in the discharge mode, but the occurrence frequency is high. It is possible to completely eliminate both of the conductive mode bearing currents in which the damaging stress is not negligible, and to completely eliminate the electrolytic corrosion of the bearings caused by these bearing currents.

  Further, in a conventional molded motor in which two conventional brackets as described in Document 4 are short-circuited with a conductive paint applied to the inner peripheral surface of the motor frame to prevent electrolytic corrosion, a uniform thickness is provided on the inner peripheral surface of the motor frame. Because it is necessary to apply conductive paint with the air brush, it is necessary to use an air brush to apply the conductive paint. However, the entire side of the motor frame with the mask treatment applied to the outer peripheral surface was applied with the conductive paint using the air brush. After that, a process such as removing the mask attached to the outer peripheral surface is necessary, and there was a problem that man-hours and costs were required for the mask attaching process and the mask removing process after applying the conductive paint. In the case of the mold motor according to the third embodiment, since the conductive paint is applied to the entire surface of the motor frame, the man-hours required for mask processing can be eliminated. It can be an effect that a molded motor structure having electrical corrosion prevention features can be realized at low cost.

  In the first and third embodiments, the connecting means is configured to electrically connect the stator core and the second conductive layer via the core connection terminal welded and fixed to the outer peripheral portion of the stator core. In addition, a part of the outer peripheral portion of the stator core may be directly connected to the second conductive layer so as to be connected to the stator core and the second conductive layer. Does not occur.

  In the second embodiment and the fourth embodiment, the connection means is configured to electrically connect the stator core and the first conductive layer via the core connection terminal welded and fixed to the inner peripheral portion of the stator core. Instead, a part of the inner peripheral portion of the stator core may be directly connected to the first conductive layer so that the stator core and the first conductive layer are connected to each other. Does not make a difference.

  In Embodiments 1 to 4, the first conductive layer is made of chained Au-Ag fine particles instead of a conductive layer formed by applying a conductive paint such as silver paint. A transparent conductive paint may be used, and there is no difference in its effect.

  In Embodiments 1 to 4, the second conductive layer is made of chained Au-Ag fine particles, instead of a conductive layer formed by applying a conductive paint such as silver paint. A transparent conductive paint may be used, and there is no difference in its effect.

  In the first to fourth embodiments, the first conductive layer is made of a metal foil such as a copper foil instead of a conductive layer formed by applying a conductive paint such as a silver paint. It is good also as a conductive layer formed so that it may cover, and does not produce a difference in the effect.

  In the first to fourth embodiments, the second conductive layer is, for example, a metal foil such as copper foil instead of a conductive layer formed by applying a conductive paint such as silver paint. The conductive layer may be formed so as to be covered with, and there is no difference in the operation effect.

  In the first to fourth embodiments, the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint such as silver paint. In addition, for example, a conductive layer formed so as to be covered with a copper metal solid body may be used, and there is no difference in the effect. The metal solid only needs to cover the entire inner peripheral surface of the motor frame, for example, a cylinder made of copper or the like.

  In the first to fourth embodiments, the second conductive layer is replaced with a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint such as silver paint. In addition, for example, a conductive layer formed so as to be covered with a metal solid body such as a substantially cylindrical shape made of copper may be used, and there is no difference in operational effects. The metal solid is only required to cover the entire outer peripheral surface of the motor frame, and examples thereof include a metal box made of copper, a cylinder made of copper, and the like.

  The electric corrosion of the bearing caused by the bearing current of the molded motor with the built-in wiring board with the inverter device that drives the molded motor can be eliminated. The present invention can also be applied to uses such as molded motors used in industrial equipment and home appliances configured to drive a motor.

Structural sectional view for explaining the structure of the molded motor according to the first embodiment Enlarged view of the connection means Side view of the stator around the connecting means viewed from the direction A shown in FIG. Model diagram showing the distribution of electrostatic coupling capacitance between parts of the mold motor The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor when the bearing of the mold motor will be in a fluid lubrication state Time chart of each part explaining that the bearing current of the discharge mode does not occur when the bearing of the mold motor is in a fluid lubrication state The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor, when the bearing of the mold motor will be in a boundary lubrication state Time chart of each part explaining that the bearing current in the conductive mode does not occur when the bearing of the mold motor is in the boundary lubrication state Structural sectional view for explaining the structure of the molded motor of the second embodiment Enlarged view of the connecting means shown in FIG. Side view of the stator around the connection means viewed from the direction C shown in FIG. Structural sectional view for explaining the structure of the molded motor of the third embodiment Model diagram showing the distribution of electrostatic coupling capacitance between parts of the mold motor The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor when the bearing of the mold motor will be in a fluid lubrication state The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor, when the bearing of the mold motor will be in a boundary lubrication state Structural sectional view for explaining the structure of the molded motor of the fourth embodiment Cross-sectional view of the structure of a conventional molded motor of Patent Document 1 Model diagram showing the distribution of electrostatic coupling capacitance between each part of the conventional molded motor Side view showing the state of the bearing when the conventional mold motor rotates at high speed The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor, when the bearing of the conventional mold motor will be in a fluid lubrication state Time chart of each part explaining the mechanism of discharge mode bearing current when the bearing of the conventional mold motor is in a fluid lubrication state Side view showing the state of the bearing when the conventional mold motor is rotating at a low speed The figure which shows the common mode equivalent circuit for demonstrating the waveform of each part of a mold motor when the bearing of the conventional mold motor will be in a boundary lubrication state Time chart of each part explaining the mechanism that generates the bearing current in the conductive mode when the bearing of the conventional molded motor is in the boundary lubrication state Model diagram showing the distribution of electrostatic coupling capacitance between each part of the conventional molded motor of Patent Document 3 The figure which shows the common mode equivalent circuit of a mold motor when the bearing of the conventional mold motor is in a fluid lubrication state The figure which shows the common mode equivalent circuit of a mold motor when the bearing of the conventional mold motor is in a boundary lubrication state

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold motor 2 Stator core 3 Insulating layer 4 Coil 6 Stator 7 Mold resin 8 Motor frame 9 Rotor 10 Inner peripheral surface 13 Rotating shaft 14 Bearing 15 Bearing 16 First conductive layer 17 Outer peripheral surface 18 Second Conductive layer 19 Connection means 20 Iron core connection terminal 21 Outer peripheral part 22 End face 23 Exposed part 28 Mold motor 29 Connection means 30 Iron core connection terminal 31 Inner peripheral part 32 End face 33 Exposed part 35 Mold motor 39 Mold motor 101 Mold motor 102 Stator core 103 Insulating layer 104 Coil 107 Wiring board 109 Rotor 110 Rotating shaft 111 Bearing 112 Bearing 119 Molded motor 120 Stator core 121 Insulating layer 122 Coil 125 Motor frame 129 Rotor 130 Rotating shaft 131 Bearing 1 2 bearings

Claims (12)

A stator with a coil wound around a resin-insulated stator core is molded integrally with mold resin, and a motor frame is provided. Of the two mounted bearings, one of the bearings is held by a metal bracket fitted to the motor frame, and the other bearing is held inside the motor frame. The motor frame includes a resin portion that covers the stator so that an exposed portion of the stator core end surface is not formed on the inner peripheral surface of the motor frame facing the rotor, and an inner peripheral surface of the motor frame. A first conductive layer formed on the entire surface; a second conductive layer formed on the entire outer peripheral surface of the motor frame; the stator core; and the first conductive layer. Connecting means for electrically connecting a layer or the second conductive layer, and enclosing the stator with the first conductive layer and the second conductive layer so as to be completely sealed A molded motor characterized by electrostatic shielding between the rotors. A stator with a coil wound around a resin-insulated stator core is molded integrally with mold resin, and a motor frame is provided. In the inner rotor type molded motor in which the two attached bearings are respectively held by two brackets fitted in the openings on the output side and the non-output side of the motor frame, the motor frame is And a resin portion covering the stator so that an exposed portion of the stator core end face is not formed on the inner peripheral surface of the motor frame facing the rotor, and a first formed on the entire inner peripheral surface of the motor frame. Electrically conductive layer, a second conductive layer formed on the entire outer peripheral surface of the motor frame, the stator core and the first conductive layer or the second conductive layer. Connecting means for connecting, and the stator is surrounded by the first conductive layer and the second conductive layer so as to be completely sealed, and the coil and the rotor are electrostatically shielded. Mold motor. After the core connection terminal is contact-fixed or welded to the outer periphery of the stator core and conducted to the stator core, an exposed portion is formed on the end surface of the core connection terminal on the outer peripheral surface of the motor frame integrally molded The stator is covered with a mold resin to form the motor frame, and the second conductive layer is formed on the entire outer peripheral surface of the motor frame so as to be electrically connected to the exposed portion of the end face of the core connection terminal. 3. The molded motor according to claim 1, further comprising a connection means that is formed so as to electrically connect the stator core and the second conductive layer. After the core connection terminal is contact-fixed or welded to the inner periphery of the stator core to be conducted to the stator core, the exposed portion is exposed to the end surface of the core connection terminal on the inner peripheral surface of the motor frame integrally molded. The stator is covered with a mold resin so as to form the motor frame, and the motor frame is formed on the inner peripheral surface of the motor frame so as to be electrically connected to the exposed portion of the end surface of the iron core connection terminal. 3. The molded motor according to claim 1, further comprising a connection means for forming a conductive layer so as to electrically connect the stator core and the first conductive layer. 3. The molded motor according to claim 1, wherein the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a conductive paint. 3. The molded motor according to claim 1, wherein the second conductive layer is a conductive layer formed by applying the entire outer peripheral surface of the motor frame with a conductive paint. 3. The molded motor according to claim 1, wherein the first conductive layer is a conductive layer formed by applying the entire inner peripheral surface of the motor frame with a transparent conductive paint. 3. The molded motor according to claim 1, wherein the second conductive layer is a conductive layer formed by applying the entire outer peripheral surface of the motor frame with a transparent conductive paint. 3. The molded motor according to claim 1, wherein the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a metal foil. 3. The molded motor according to claim 1, wherein the second conductive layer is a conductive layer formed so as to cover the entire outer peripheral surface of the motor frame with a metal foil. 3. The molded motor according to claim 1, wherein the first conductive layer is a conductive layer formed so as to cover the entire inner peripheral surface of the motor frame with a metal solid. 3. The molded motor according to claim 1, wherein the second conductive layer is a conductive layer formed so as to cover the entire outer peripheral surface of the motor frame with a solid metal.

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