JP2008017635A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor capable of easily switching the presence and absence of a lead line or a capacitor for measures against noise from the outside of the motor in assembling the motor manufactured as one type of a motor into an apparatus. <P>SOLUTION: This motor 1 includes a printed circuit board 14, a bracket 17 for covering the circumference of a stator 2, and a bracket cover 15. On the printed circuit board 14, there are provided a connecting pin 14b for a circuit board side connector 14a engaged with a cable-side connector 20, a capacitor 14c for measures against noise, and a ground contact terminal 14d brought into contact with a projection 15a of the bracket cover 15. These elements are connected in series. On the other hand, negative power supply is applied to a D terminal of a socket terminal 20b, and terminals E and F of the socket terminal 20b are connected by a short wire 20c. The presence and absence of the capacitor 14c are selected from the presence and absence of the short wire 20c. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor, and more particularly to a connection structure of a noise countermeasure member that reduces a noise signal generated when the electric motor is driven.

  In general, an electric motor generates a noise signal due to a spark generated from a brush. For this reason, a structure in which a noise removing capacitor is connected to an electric motor in order to reduce the noise signal is generally used.

  FIG. 5 is a perspective view of a brush type small motor to which a noise removing capacitor is connected. This motor has a structure in which a convex portion 84 a extends from the end of a cylindrical metal case 84, and a plus terminal 81 and a minus terminal 82 for power supply are mounted on the rear side of the metal case 84. The structure protrudes from the resinous bracket 83.

  One terminal of the capacitor 86 is soldered to the plus terminal 81 or the minus terminal 82, and the other terminal of each capacitor 86 is soldered to the convex portion 84a (see, for example, Patent Document 1).

  This circuit constitutes an electrical bypass path in which a noise signal generated from the inside of the main body and flowing to the housing (bracket 83) flows toward a power source (plus terminal 81 or minus terminal 82) having a relatively low impedance. Therefore, a capacitor 86 is used as a noise countermeasure member.

  On the other hand, in the case of a method of use in which there is no problem even if a drive power supply voltage is directly applied to the metal case of the motor, as shown in the side view of the motor of FIG. 6, a negative terminal 92 for power supply and a metal case 90 are provided. There is also a method of connecting directly via the lead wire 91 without using a capacitor (see, for example, Patent Document 2).

  In this case, the lead wire 91 is used as a substitute for the capacitor of the noise countermeasure member.

  By the way, in recent years, besides brush-type motors, brushless motors are also widely used in various devices. However, even in this brushless motor, switching noise occurs when the drive current is switched, and the metal part of the casing of the motor It has the same problem as a brush type motor that noise current flows.

  Next, the structure of the brushless motor will be described. FIG. 7 is a cross-sectional view of an axial gap type electric motor.

  This axial gap type electric motor 1 includes a substantially disc-shaped stator 2 and a pair of rotors 8 and 9 that are arranged opposite to each other with a predetermined gap on both sides of the stator 2, and the rotors 8 and 9 rotate in the same manner. The shaft 4 (rotor output shaft) is shared, and the stator 2 includes a bearing portion 26 that supports the rotor rotation shaft 4 on the inner peripheral side thereof. A cylindrical bracket 17 made of a steel plate is attached to the outer periphery of the stator 2.

  The stator 2 includes a stator core 5 formed in an annular shape (a so-called donut shape) and a bearing portion 26 that is coaxially inserted on the inner peripheral side of the stator core 5, and these are integrally molded with a synthetic resin 7. The stator 2 is configured. In this example, the bearing portion 26 includes two radial ball bearings.

  This electric motor has a bracket lid 15, a printed circuit board 14 mounted with a motor drive circuit, a rotor 8, a stator 2, a rotor 9, and a bracket lid 16, which are each circular around the rotor rotating shaft 4. It is installed.

  The rotor 8 includes a permanent magnet 8b on one surface of the back yoke 8a made of a steel plate facing the stator core 5 and a permanent magnet 8c for position detection on the other surface. The rotor 9 includes a permanent magnet 9b on one surface of the back yoke 9a made of a steel plate facing the stator core 5.

  A hall element 14c is arranged on the printed circuit board 14 facing the permanent magnet 8c for detecting the position of the rotor 8, and the rotational position of the rotor 8 is detected. In addition, the winding connection terminal 11 a of the connection body 11 is soldered near the outer periphery of the printed circuit board 14, and the lead wire of the coil 27 of the stator 2 is connected to the printed circuit board 14 through the connection body 11. ing.

  The bracket lids 15 and 16 are formed by pressing a steel plate, and are structured to be press-fitted into stepped portions 17 a provided on both sides of the bracket 17. The bracket lids 15 and 16 and the bracket 17a constitute a casing of the axial gap type electric motor 1. Therefore, the entire housing of the electric motor is made of metal (metal part). Depending on the type of electric motor, the bracket 17 may be made of resin, and only the bracket lids 15 and 16 may be metal parts. Further, a board-side connector 14 a having connection pins 14 b is arranged on the printed board 14, and is coupled to the cable-side connector 20.

  On the other hand, as shown in the perspective view of FIG. 8, the stator 2 has a bearing portion disposed on the inner peripheral side of the stator core 5, and an outer peripheral portion and an inner peripheral portion of the stator core 5 by insert molding and a bearing portion in contact with the inner peripheral portion. And a lead wire connection body 11 are hardened with a synthetic resin.

  The stator 2 is provided with a step portion 2b to which the vicinity of the outer periphery of the printed board is fitted. In addition, after the insert molding, the winding connection terminal 11a and the board positioning boss 11c of the connection body 11 are exposed.

  Then, the winding connection terminal 11 a protruding in the vertical direction of the connection body 11 is inserted into the hole 14 a of the printed board 14 on which the drive circuit for the electric motor is mounted, and is soldered to the land pattern of the printed board 14. At the same time, the board positioning boss 11c of the connection body 11 and the cutout 14b of the printed board 14 are fitted together.

  When the printed board 14 is mounted on the step 2b of the stator 2, the board-side connector 14a disposed on the printed board 14 is exposed from the notch 17b provided on the outer periphery of the bracket 17. Yes. A cable-side connector (not shown) is attached to the board-side connector 14a so that control signals and power can be supplied from the control board to the motor side.

  Thus, unlike a brush motor, the brushless motor has a complicated structure and is an expensive electric motor. Furthermore, in recent years, there are many electric motors mounted on electronic devices, and the specifications are diverse. To cope with this, the types of electric motors tend to increase.

  Since electric motors are used for a wide variety of applications in this way, humans directly touch the case of the motor or use it in a structure that touches the person electrically via a sheet metal attached to the motor. This causes a malfunction of the device due to the static electricity charged in the device being discharged inside the device.

  For example, in recent years, the drive control of an electric motor is often performed by a microcomputer, and the electric motor and the microcomputer are often designed to share the same power source. For this reason, if a noise countermeasure member consisting of a capacitor or lead wire is placed between the power supply voltage and the housing of the motor and electrically connected, the static electricity will reversely pass through these noise countermeasure members to the power supply and microcomputer. In some cases, the microcomputer was runaway.

  For this reason, an electronic device that directly touches the case of the motor, or that touches the person electrically via a sheet metal or the like to which the motor is attached, requires a motor with a structure that does not have a noise countermeasure lead or capacitor. On the other hand, if the electric motor is used in an electronic device that is completely insulated in the device, noise can be reduced by using the configuration shown in FIGS.

However, as mentioned above, there are a large number of types of motors, and motor manufacturers must prepare products with and without noise-added lead wires and capacitors, as the product lineup increases. There were extra man-hours and expenses for switching production processes, inventory management, and parts management. The same is true for equipment manufacturers that use these motors, and extra man-hours and costs have been incurred for parts inventory management and ordering.
Japanese Utility Model Publication No. 62-101378 (page 4-5, FIG. 1) Japanese Utility Model Publication No. 61-98367 (page 3, FIG. 4)

  The present invention solves the above-mentioned problems, and it is produced as one type of electric motor during production, and when it is incorporated into equipment, it can be easily switched from the outside of the electric motor to add or remove noise-preventing lead wires and capacitors. An object is to provide an electric motor that can be used.

In order to solve the above-described problems, the present invention provides a housing provided with a metal portion made of metal, a printed circuit board provided inside the housing, and signals and power supplied from the outside of the housing. In an electric motor comprising a connector that relays to a circuit, and a noise countermeasure member that constitutes an electrical bypass path for flowing a noise signal generated from the inside of the housing and flowing to the metal part toward the power source,
A part of the bypass path is led out of the housing of the electric motor through the connector, and the bypass path thus derived is connected or not connected.

  Further, the noise countermeasure member, the connector, and a ground contact terminal that is electrically connected to the inner surface of the metal part are provided on the printed board, and a part of the bypass path that connects these is provided on the printed board. The wiring pattern is formed.

Alternatively, a housing having a metal portion made of metal, a printed circuit board provided inside the housing, a connector for relaying a signal or power supplied from outside the housing to an internal electric circuit, and the housing In an electric motor comprising a noise countermeasure member that constitutes an electrical bypass path for flowing a noise signal generated from inside the body and flowing in the metal part toward the power source,
On the printed circuit board, the noise countermeasure member and a ground connection terminal are provided, and the bypass path for connecting them is formed with a pattern of the printed circuit board,
A gap is provided between the ground connection terminal and the inner surface of the metal part of the housing, and the metallic conduction terminal mounted from the outside of the metal part and the ground connection terminal are electrically connected.
Alternatively, the ground connection terminal and the inner surface of the metal part are electrically connected, and an insulating insulating terminal attached from the outside of the metal part electrically connects the ground connection terminal and the inner surface of the metal part. Connect.

By using the above means, according to the electric motor according to the present invention,
In the invention according to claim 1, since the path for bypassing noise is led out of the casing of the motor, the bypass path can be connected / unconnected outside the motor. Therefore, an electric motor manufacturer can mount a noise countermeasure member to produce an electric motor, and an equipment manufacturer equipped with the electric motor can select and use bypass path connection / disconnection.

  For this reason, electric motor manufacturers suppress the increase in product lineup and reduce unnecessary man-hours and expenses such as production process switching, inventory management, and parts management, and even equipment manufacturers that use these motors manage parts inventory. And extra man-hours and expenses in ordering can be reduced.

  In the invention according to claim 2, a noise countermeasure member, a connector, and a ground connection terminal that is electrically connected to the inner surface of the metal part are provided on the printed board, and these are connected by a wiring pattern of the printed board. For this reason, since the ground connection terminal and the housing automatically come into contact with each other during the assembly of the motor, the printed circuit board that has been used conventionally is effectively used, and the number of steps for assembling the motor is hardly increased.

In the invention according to claim 3, a gap is provided between the ground connection terminal and the inner surface of the metal part, and the metallic conduction terminal and the ground connection terminal attached from the outside of the metal part are electrically connected.
Alternatively, the ground connection terminal and the inner surface of the metal part are electrically connected, and the insulating insulating terminal attached from the outside of the metal part has a structure in which the ground connection terminal and the inner surface of the housing are electrically disconnected.
By attaching a metallic conductive terminal or an insulating insulating terminal from the outside of the housing, it is possible to easily connect / disconnect a bypass path for bypassing noise outside the motor.

  In addition, by configuring the noise countermeasure member with a plurality of capacitors with different capacities and providing a plurality of bypass paths that bypass the noise, a plurality of capacitor capacities can be selected with a simple structure corresponding to the noise generation frequency, A general-purpose electric motor capable of dealing with a wide range of noise frequencies can be obtained. For this reason, the number of types of electric motors can be reduced to a minimum number, and production and order management are facilitated.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail as examples based on the attached drawings.

  A feature of the present invention resides in that a lead wire or a capacitor for noise suppression is mounted in the motor in advance, and switching means for switching these connections from the outside of the motor is provided.

  FIG. 1A is an explanatory view seen from the side for explaining the structure of an axial gap type electric motor according to the present invention. In the following description, the structures described in FIG. 7 and FIG.

  The electric motor 1 is pivotally supported at the center of the stator 2 having a cylindrical shape, a disk-shaped rotor 8 disposed on a side surface thereof, a disk-shaped printed circuit board 14 provided with a drive circuit for the stator 2, and A rotating shaft 4 fixed to the rotor 8, a cylindrical bracket 17 covering the periphery of the stator 2, and a bracket lid 15 attached to the end face are provided. The cylindrical bracket 17, the bracket lid 15 attached to this end face, and another bracket lid (not shown) constitute a metal part of the casing of the electric motor 1.

  A printed circuit board 14 is provided with a board-side connector 14a having six connection pins 14b of a to f. The board-side connector 14a is adapted to be fitted with a cable-side connector 20 connected to a control board (not shown) with a lead wire 20a. The connection pins 14b of a to f of the board side connector 14a correspond to the socket terminals 20b of A to F of the cable side connector 20.

  A negative power supply (GND) is applied to the terminal D of the socket terminal 20b. The terminals E and F of the socket terminal 20b are connected by a short wire 20c. Signals for controlling the positive power source and the electric motor 1 are supplied to the other terminals A to C of the socket terminal 20b from a control board (not shown).

  On the other hand, the printed circuit board 14 is provided with a capacitor 14c for noise suppression and a ground connection terminal 14d, and one electrode of the capacitor 14c for noise suppression is electrically connected to the ground connection terminal 14d, and the other The electrode is electrically connected to the connection pin 14b of f of the board side connector 14a. Further, the connection pin 14b between d and e is electrically connected.

  In FIG. 1, for ease of explanation, these connections are shown in the form of lead wires, but in an actual device, they are connected by a pattern of the printed circuit board 14. Further, in the following description, connection means an electrical connection unless otherwise specified.

  Next, the structure of the ground connection terminal 14d will be described with reference to the perspective view of FIG.

  The ground connection terminal 14d has a structure in which a rectangular leaf spring is bent in an L shape. The contact portion 14da is bent right by 90 degrees, and includes two pin terminals 14dc that extend downward from both sides of the lower end portion of the holding portion 14db and are soldered to the printed circuit board 14.

  As described above, since the ground connection terminal 14d is made of a leaf spring, the ground connection terminal 14d has elasticity. When a stress is applied to the contact portion 14da from above to below, the ground connection terminal 14d bends downward as indicated by a dotted line. .

  As shown in FIG. 1A, the ground connection terminal 14d is installed upright on the printed circuit board 14. The contact portion 14da of the ground connection terminal 14d is in contact with the protrusion 15a provided on the inner surface of the bracket lid 15 (part of the metal portion). Note that the height of the protrusion 15a is such that a sufficient stress is applied to the contact portion 14da, and the bracket lid 15 and the ground connection terminal 14d are electrically connected. Since the bracket lid 15 is press-fitted into the bracket 17, they are also electrically connected.

  Accordingly, when the cable-side connector 20 is attached to the board-side connector 14a, the bracket lid 15 and the bracket 17 are connected to the protrusion 15a, the ground connection terminal 14d, the capacitor 14c, the terminal f of the board-side connector 14a, and the F of the cable-side connector 20. The terminals, the E terminal, the e terminal of the board-side connector 14a, and the d terminal are electrically connected in this order.

  As described above, since the minus power is supplied from the control board to the terminal d of the board-side connector 14a, the casing (bracket and bracket lid) of the electric motor 1 is connected to the minus power via the capacitor 14c. Will be. This has the same circuit configuration as the capacitor 86 connected to the minus terminal 82 described in FIG. Therefore, the usage method is to mount a noise countermeasure capacitor.

  If the capacitor is not mounted with a noise countermeasure capacitor, the E and F terminals of the socket terminal 20b of the cable-side connector 20 are not connected by the short wire 20c, but are left open. The signal bypass path is cut off, which is the same as when the capacitor 14c is not attached.

  Thus, since the path for bypassing noise is derived to the outside of the electric motor, the bypass path can be connected / unconnected outside the electric motor. Therefore, an electric motor manufacturer can mount a noise countermeasure member to produce an electric motor, and an equipment manufacturer equipped with the electric motor can select and use bypass path connection / disconnection.

  For this reason, electric motor manufacturers suppress the increase in product lineup and reduce unnecessary man-hours and expenses such as production process switching, inventory management, and parts management, and even equipment manufacturers that use these motors manage parts inventory. And extra man-hours and expenses in ordering can be reduced.

  Further, a noise countermeasure member, a connector, and a ground connection terminal that is electrically connected to the inner surface of the metal part of the housing are provided on the printed board, and these are connected by a pattern of the printed board. In addition, since the ground connection terminal and the housing automatically come into contact with each other during the assembly of the motor, the printed circuit board that has been used conventionally is effectively used, and the number of steps for assembling the motor is hardly increased.

  In addition, although the present Example demonstrates the example which connects the metal part of the housing | casing of the electric motor 1 and a negative power supply via a capacitor | condenser, it is not restricted to this, The metal part of the housing | casing of the electric motor 1 and plus A method of connecting to a power source may be used, or these may be provided side by side. Further, a system using a short wire instead of the capacitor may be used.

  Next, a modification of FIG. 1 will be described with reference to FIG. Detailed description of the same configuration as in FIG. 1 is omitted. A major difference from FIG. 1 is that the number of terminals of the board-side connector 14a and the cable-side connector 20 is changed from six to five.

  A board-side connector 14 a having five connection pins 14 a to e is mounted on the printed board 14. The board-side connector 14a is adapted to be fitted with a cable-side connector 20 connected to a control board (not shown) with a lead wire 20a. The connection pins 14b of a to e of the board side connector 14a correspond to the socket terminals 20b of A to E of the cable side connector 20.

  A negative power supply (GND) is applied to the terminal D of the socket terminal 20b. The terminals D and E of the socket terminal 20b are connected by a short wire 20c. Signals for controlling the positive power source and the electric motor 1 are supplied to the other terminals A to C of the socket terminal 20b from a control board (not shown).

  On the other hand, the printed circuit board 14 is provided with a capacitor 14c for noise suppression and a ground connection terminal 14d, and one electrode of the capacitor 14c for noise suppression is electrically connected to the ground connection terminal 14d, and the other The electrode is electrically connected to the connection pin 14b of e of the board side connector 14a.

  Therefore, when the cable-side connector 20 is attached to the board-side connector 14a, the bracket lid 15 and the bracket 17 are connected to the protrusion 15a, the ground connection terminal 14d, the capacitor 14c, the terminal e of the board-side connector 14a, and the E of the cable-side connector 20. The terminal is connected in order with the terminal D (negative power source).

  For this reason, if it is desired to use in a manner that does not include a noise countermeasure capacitor, the D and E terminals of the socket terminal 20b of the cable-side connector 20 are not connected by the short wire 20c, but are left open. The noise signal bypass path is cut off, which is the same as when no capacitor is attached.

  In the above two examples, the noise signal bypass path is led out to the cable-side connector outside the motor via the board-side connector, and the cable-side connector is short-circuited or opened. However, the present invention is not limited to this structure, and an ON / OFF switch may be provided on the printed circuit board so that the noise signal bypass path is turned on / off inside the electric motor. In this case, the switch is exposed to the casing of the motor or a window is provided so that the switch can be operated from the outside of the motor.

  Next, a modification of FIG. 2 will be described with reference to FIG. Detailed description of the same configuration as in FIG. 2 is omitted. A major difference from FIG. 2 is that the metal part of the casing of the electric motor 1 and the capacitor are connected not via the ground connection terminal 14d inside the electric motor 1 but outside the casing.

  A board-side connector 14 a having five connection pins 14 a to e is mounted on the printed board 14. The board-side connector 14a is adapted to be fitted with a cable-side connector 20 connected to a control board (not shown) with a lead wire 20a. The connection pins 14b of a to e of the board side connector 14a correspond to the socket terminals 20b of A to E of the cable side connector 20.

  A negative power supply (GND) is applied to the terminal D of the socket terminal 20b. The E terminal of the socket terminal 20b is connected to the ground wire 20d. A ground terminal 19 is fixed to the tip of the ground wire 20d, and the ground terminal 19 is screwed to the bracket lid 15 using a metal screw 18. Signals for controlling the positive power source and the electric motor 1 are supplied to the other terminals A to C of the socket terminal 20b from a control board (not shown).

  On the other hand, the printed circuit board 14 is provided with a noise countermeasure capacitor 14c. One electrode of the noise countermeasure capacitor 14c is connected to the connection pin 14b of e of the board-side connector 14a, and the other electrode is a board. It is connected to the connection pin 14b (minus power supply) of d of the side connector 14a.

  Therefore, when the cable side connector 20 is attached to the board side connector 14a, the bracket lid 15 (metal part) and the bracket 17 (metal part) are connected to the ground terminal 19, the ground wire 20d, the E terminal of the cable side connector 20, and the board side. The terminal e of the connector 14a, the capacitor 14c, and the terminal d (negative power source) of the board-side connector 14a are connected in this order.

  For this reason, if it is desired to use a capacitor for preventing noise, if the ground terminal 19 at the tip of the ground wire 20d is not screwed to the metal part of the casing of the motor and is left open, the noise described above The signal bypass path is cut off, which is the same as when no capacitor is installed.

  Next, a modification of FIG. 3 will be described with reference to FIG. Detailed description of the same configuration as in FIG. 3 is omitted. A major difference from FIG. 1 is that the number of terminals of the board-side connector 14a and the cable-side connector 20 is changed from five to four. This is the same number of pins as in FIGS. 7 to 8 described in the background art. For this reason, a structure is adopted in which whether or not a capacitor is added is switched depending on whether a metal screw 18 that is a conduction terminal or a plastic screw 18 'that is an insulating terminal is screwed.

  A printed circuit board 14 is provided with a board-side connector 14a provided with four connection pins 14b from a to d. The board-side connector 14a is adapted to be fitted with a cable-side connector 20 connected to a control board (not shown) with a lead wire 20a. The connection pins 14b of a to d of the board-side connector 14a correspond to the socket terminals 20b of A to D of the cable-side connector 20.

  A negative power supply (GND) is applied to the terminal D of the socket terminal 20b. Signals for controlling the positive power source and the electric motor 1 are supplied to the other terminals A to C of the socket terminal 20b from a control board (not shown).

  On the other hand, the printed circuit board 14 is provided with a capacitor 14c for noise suppression and a ground connection terminal 14d, and one electrode of the capacitor 14c for noise suppression is electrically connected to the ground connection terminal 14d, and the other The electrode is electrically connected to the connection pin 14b of d of the board side connector 14a. Note that the contact portion 14da of the ground connection terminal 14d is in a dotted line state (not in contact with the bracket lid 15) if there is no external stress.

  The ground connection terminal 14d is installed upright on the printed circuit board 14. The metal screw 18 is screwed from the outside of the bracket lid 15 (metal portion), so that the contact portion 14da of the ground connection terminal 14d is in contact with the tip of the metal screw 18. The metal screw 18 is long enough to apply sufficient stress to the contact portion 14da, and electrically connects the bracket lid 15 and the ground connection terminal 14d. Since the bracket lid 15 is press-fitted into the bracket 17, they are also electrically connected.

  Therefore, when the cable-side connector 20 is attached to the board-side connector 14a, the bracket lid 15 and the bracket 17 are connected to the metal screw 18, the ground connection terminal 14d, the capacitor 14c, and the terminal d of the board-side connector 14a (minus power). Are connected in order.

  For this reason, if the usage method is not to mount a capacitor for noise suppression, if the metal screw 18 is not screwed and left open, the noise signal bypass path is cut and the capacitor is not mounted. Be the same.

  As described above, since the metal screw 18 screwed from the outside of the casing is in electrical contact with the ground connection terminal, connection / non-connection of the bypass path that bypasses noise is determined depending on whether the metal screw is screwed. This can be done easily outside the motor. Moreover, a metal screw can be used as a very inexpensive changeover switch.

  This structure is a method that does not require an increase in the number of connection pins 14b of the board-side connector 14a even when a plurality of capacitors are used. For example, another set of these same circuits can be added and used together. Next, a description will be given of a case where two sets of circuits are performed, and a configuration in which connection / non-connection of a bypass path for bypassing noise can be easily performed outside the motor depending on whether or not an insulating screw is screwed. Are explained together.

  For example, when a plastic screw 18 ′ can be screwed onto the bracket lid 15 (metal part) and the plastic screw 18 ′ is not attached, the ground connection terminal 14 d ′, the capacitor 14 c ′, and the board side connector 14 a d The terminal is connected to the terminal (minus power supply) in order. For this reason, as shown in FIG. 4, the ground connection terminal 14 d ′ is bent so that the contact portion 14 da faces obliquely upward so as to contact the bracket lid 15 when the plastic screw 18 ′ is not attached. (For example, bend at an angle of 130 ° instead of 90 °).

  Here, if the plastic screw 18 ′ is screwed, the contact portion 14da is separated from the inner surface of the bracket lid 15 (metal portion) as indicated by the dotted line, so that the capacitor 14c ′ does not function, and only the capacitance of the capacitor 14c. Take measures against noise. On the other hand, if the plastic screw 18 ′ is not screwed, the contact portion 14 da remains in contact with the inner surface of the bracket lid 15, so that the capacitor 14 c ′ functions, and the total capacity of the capacitor 14 c and the capacitor 14 c ′ causes noise. Measures can be taken.

  With such a structure, the capacitor 14c and the capacitor 14c ′ are not connected at all, depending on the combination of whether or not the metal screw 18 and the plastic screw 18 ′ are mounted. You can choose. If the capacitances of the capacitor 14c and the capacitor 14c ′ are set to different values, a plurality of capacitances can be selected with a simple structure corresponding to the noise generation frequency using the above-described combination, and a wide range of noise frequencies can be handled. A general-purpose electric motor can be obtained. For this reason, the number of types of electric motors can be reduced to a minimum number, and production and order management are facilitated.

It is explanatory drawing which shows the 1st Example of the electric motor by this invention, (A) is a side view of an electric motor, (B) is a perspective view of a contact terminal. It is explanatory drawing seen from the side surface which shows the 2nd Example of the electric motor by this invention. It is explanatory drawing seen from the side surface which shows the 3rd Example of the electric motor by this invention. It is explanatory drawing seen from the side surface which shows the 4th Example of the electric motor by this invention. It is a perspective view which shows the attachment of the capacitor | condenser in the conventional electric motor. It is a side view which shows attachment of the ground wire in the conventional electric motor. It is sectional drawing which shows the conventional axial gap type motor. It is a principal part perspective view of the conventional axial gap type motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Stator 4 Rotating shaft 8 Rotor 14 Printed circuit board 14a Board side connector 14a Connection pin 14b Connection pin 14c Capacitor 14c 'Capacitor 14d Ground connection terminal 14d' Ground connection terminal 14da Contact part 14db Holding part 14dc Pin terminal 15 Bracket lid (metal) Part)
15a Protrusion 17 Bracket (metal part)
18 Metal screw (conduction terminal)
18 'Plastic screw (insulated terminal)
19 Ground terminal 20 Cable side connector 20a Lead wire 20b Socket terminal 20c Short wire 20d Ground wire

Claims (3)

A case provided with a metal part made of metal, a printed circuit board provided inside the case, a connector for relaying a signal or power supplied from outside the case to an internal electric circuit, and the inside of the case In a motor provided with a noise countermeasure member that constitutes an electrical bypass path for flowing a noise signal generated from the metal portion and flowing toward the power source,
An electric motor characterized in that a part of the bypass path is led out of the housing of the motor via the connector, and the bypass path thus derived is connected or not connected.   On the printed board, the noise countermeasure member, the connector, and a ground contact terminal that is electrically connected to the inner surface of the metal part are provided, and a part of the bypass path that connects them is wired on the printed board. The electric motor according to claim 1, wherein the electric motor is formed in a pattern. A case provided with a metal part made of metal, a printed circuit board provided inside the case, a connector for relaying a signal or power supplied from the outside of the case to an internal electric circuit, and the inside of the case In a motor provided with a noise countermeasure member that constitutes an electrical bypass path for flowing a noise signal that flows from the metal part and flows toward the power source,
On the printed circuit board, the noise countermeasure member and a ground connection terminal are provided, and the bypass path for connecting them is formed with a pattern of the printed circuit board,
A gap is provided between the ground connection terminal and the inner surface of the metal part of the housing, and the metallic conduction terminal mounted from the outside of the metal part and the ground connection terminal are electrically connected.
Alternatively, the ground connection terminal and the inner surface of the metal part are electrically connected, and an insulating insulating terminal attached from the outside of the metal part electrically connects the ground connection terminal and the inner surface of the metal part. An electric motor characterized by being connected.

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