JP5971520B2 - motor - Google Patents

Description

  The present invention relates to an inner rotor type motor.

Conventionally, in an office machine such as a copying machine or a multifunction machine, an inner rotor type motor is used as a drive source. For example, in a DC brushless motor disclosed in Japanese Patent Application Laid-Open No. 2008-54390, a sensor substrate is attached to the front surface of an electrical insulating member of a stator. The sensor substrate is pressed and fixed to the bottom of the stepped portion, which is the front end surface of the electrical insulating member, by three engaging claws provided on the electrical insulating member. Three magnetic sensors for detecting the position of the magnetic poles of the rotor are attached to the sensor substrate. In the motor disclosed in Japanese Patent Application Laid-Open No. 2011-167054, the circuit board is fixed to the insulator by welding.
JP 2008-54390 A Japanese Patent Application Laid-Open No. 2011-167054

  By the way, when the circuit board is attached by screws or welding, the time required for the attachment increases. On the other hand, as in Japanese Patent Application Laid-Open No. 2008-54390, when an engaging claw is used, a large force acts on the circuit board when the circuit board is attached, and there is a risk that the electronic component or circuit is damaged.

  The present invention has been made in view of the above problems, and a main object of the motor is to reduce the number of mounting steps while preventing the circuit board from being warped when the circuit board is mounted.

  An exemplary motor according to one aspect of the present invention includes a motor main body portion and a cap member attached to the motor main body portion, and the motor main body portion has an annular shape centering on a central axis facing in the vertical direction. Of the stator, a cover member that covers the outer periphery of the stator, a bearing that is directly or indirectly fixed to the cover member via another member, and the bearing that is rotatably supported about the central axis A rotor shaft connected to the shaft, a rotor magnet attached to the rotor holder and disposed inside the stator, and positioned above the stator and perpendicular to the central axis A circuit board that extends, and a board seat that is positioned above the coil of the stator and is in contact with the lower surface of the circuit board. A canopy covering the top of the circuit board, a cylindrical part extending from the outer edge of the canopy to the motor main body, and elastically deforming in contact with the upper surface of the circuit board, utilizing a restoring force An elastic portion that applies a downward force to the circuit board.

  According to the present invention, it is possible to reduce the number of circuit board mounting steps in a motor. Further, it is possible to prevent the circuit board from warping when the circuit board is attached.

FIG. 1 is a front view of the motor. FIG. 2 is a longitudinal sectional view of the motor. FIG. 3 is a longitudinal sectional view of the motor. FIG. 4 is a plan view of the motor before the circuit board is attached. FIG. A is a perspective view of a cap member. FIG. B is a perspective view of a cap member. FIG. 6 is a longitudinal sectional view in the vicinity of the elastic portion. FIG. 7 is a longitudinal sectional view of the elastic portion. FIG. 8 is a diagram showing a flow of manufacturing the motor. FIG. 9 is a longitudinal sectional view showing another example of the elastic portion.

  In the present specification, in the direction parallel to the central axis, the upper side in FIG. 2 is referred to as “upper side”, and the lower side in FIG. 2 is simply referred to as “lower side”. The expressions “upper” and “lower” do not necessarily coincide with the direction of gravity. A radial direction centered on the central axis is simply referred to as “radial direction”, a circumferential direction centered on the central axis is simply referred to as “circumferential direction”, and a direction parallel to the central axis is simply referred to as “axial direction”.

  FIG. 1 is a front view of a motor 1 according to an exemplary embodiment of the present invention. 2 and 3 are longitudinal sectional views of the motor 1. The motor 1 is an inner rotor type motor used as a drive source for office equipment such as a copying machine, a printer, and a multifunction machine.

  As shown in FIG. 2, the motor 1 includes a rotating part 11, a stationary part 12, two bearings 13, an encoder 14, and a cap member 15. The rotating unit 11 rotates around a central axis J1 that faces in the vertical direction. In FIG. 2, the rotating part 11 is located below the stationary part 12. The output shaft of the rotating part 11 faces downward. Hereinafter, the part other than the cap member 15 of the motor 1 is referred to as a “motor body 10”.

  The bearing 13 is fixed to the stationary part 12 and supports the rotating part 11 rotatably. The bearing 13 is an oil-impregnated sleeve. The cap member 15 has a substantially cylindrical shape with a lid and covers the top of the stator 122. The encoder 14 is located in the cap member 15.

  The rotating unit 11 includes a shaft 111, a rotor holder 112, and a rotor magnet 113. The shaft 111 has a substantially cylindrical shape centered on the central axis J1 and is rotatably supported by the bearing 13. The rotor holder 112 is connected to the side opposite to the output side of the shaft 111. The rotor holder 112 includes a shaft fixing part 211, a connection part 212, and a cylindrical part 213. The shaft fixing portion 211 is fixed to the shaft 111 on the upper side of the upper bearing 13. The connecting portion 212 extends radially outward from the shaft fixing portion 211. The cylindrical portion 213 extends downward from the outer edge of the connection portion 212. The rotor magnet 113 is attached to the outer surface of the cylindrical portion 213. The rotor magnet 113 may be cylindrical, or a plurality of magnets arranged in the circumferential direction. The rotor holder 112 is shaped by pressing a thin plate. The thin plate is formed of, for example, a magnetic material that is a metal.

  Two resin plates 214 are disposed between the shaft fixing portion 211 and the upper bearing 13. A stopper 215 is attached to the shaft 111 below the lower bearing 13. The shaft fixing portion 211 and the stopper 215 prevent the shaft 111 from moving in the vertical direction.

  As shown in FIG. 3, the stationary part 12 includes a cover member 121, a stator 122, and a circuit board 123. The cover member 121 includes an inner cylinder part 221, an outer cylinder part 222, and a bottom part 223. The inner cylinder part 221 and the outer cylinder part 222 are cylindrical with the central axis J1 as the center, and are arranged coaxially. The bottom part 223 connects the lower end of the outer cylinder part 222 and the lower end of the inner cylinder part 221. The bottom 223 is provided with a plurality of mounting holes 224 for mounting the motor 1 at a desired position. The inner cylinder portion 221 supports the bearing 13 on the inner side surface 225. The outer cylindrical portion 222 covers the outer periphery of the stator 122 and supports the stator 122 with the inner side surface 226. The cover member 121 is molded by pressing a single plate member that is a metal. Preferably, the cover member 121 is a conductive member. More preferably, the cover member 121 is a magnetic body.

  Stator 122 includes a stator core 231, an insulator 232, and a coil 233. The stator 122 has an annular shape centered on the central axis J1. The stator core 231 is formed by stacking a plurality of thin magnetic steel plates in the vertical direction. The stator core 231 includes an annular core back 241 and a plurality of teeth 242. The core back 241 is press-fitted into the outer cylinder portion 222. The teeth 242 extend inward in the radial direction from the core back 241. The rotor magnet 113 is disposed inside the stator 122. The tip of the teeth 242 faces the rotor magnet 113 in the radial direction. The insulator 232 is made of resin. The insulator 232 covers the stator core 231.

  The circuit board 123 is located above the stator 122 and spreads in a direction perpendicular to the central axis J1. The circuit board 123 is held above the insulator 232. FIG. 4 is a plan view of the motor 1 before the circuit board 123 is attached. FIG. 3 shows a cross section at the position of the arrow AA shown in FIG. As shown in FIGS. 3 and 4, the insulator 232 includes nine upper partial insulators 251 and nine lower partial insulators 252. One set of upper partial insulator 251 and lower partial insulator 252 arranged one above the other constitutes one partial insulator corresponding to one tooth 242. In other words, the insulator 232 includes partial insulators respectively corresponding to the plurality of teeth 242. The upper partial insulator 251 covers the upper surface and upper half of the side surface of one tooth 242.

  The upper partial insulator 251 includes an outer protrusion 261 and an inner protrusion 262. The outer protruding portion 261 protrudes above the upper end 227 of the outer cylindrical portion 222 on the radially outer side of the coil 233. The outer protruding portion 261 is also an upper portion of the outer cylindrical portion 222 of the insulator 232. The inner protruding portion 262 protrudes upward on the upper side of the tip of the tooth 242.

  As will be described later, the upper portion of the outer protruding portion 261 functions as a substrate seat that contacts the lower surface of the circuit substrate 123. Hereinafter, the upper portion of the outer protruding portion 261 is referred to as a “substrate seat portion 28”, and the substrate seat portion 28 will be described as being not included in the insulator 232. Of course, in the present embodiment, the substrate seat 28 is a part of a member constituting the insulator 232. The upper partial insulator 251 and the substrate seat 28 are collectively referred to as “upper partial insulator component 250”. Such an upper partial insulator component 250 reduces the number of components of the motor 1 as compared with the case where the substrate seat 28 is separately provided. As shown in FIG. 3, the substrate seat 28, more precisely the seating surface, is located above the coil 233.

  The lower partial insulator 252 covers the lower surface of one tooth 242 and the lower half of the side surface. The lower partial insulator 252 includes an outer protrusion 263 that protrudes downward on the radially outer side of the coil 233, and an inner protrusion 264 that protrudes downward below the tip of the tooth 242. The stator core 231 is covered by the upper partial insulator 251 and the lower partial insulator 252 except for the outer surface of the core back 241 and the tip surface of the teeth 242.

  The upper partial insulator component 250 has three different shapes. As shown in FIG. 4, one includes a pin 265 which is a convex portion provided on the upper end surface of the substrate seat portion 28 and protruding further upward. The other includes a protrusion 266 having a low height on the outer surface 270 of the outer protrusion 261. The outer surface 270 of the outer protrusion 261 is also the outer surface of the upper partial insulator 251. The other includes a through hole 267 that vertically penetrates the outer protrusion 261 to the stator core 231. Three sets of these three types of upper partial insulator parts 250 are arranged in the circumferential direction.

  As shown in FIG. 3, the pins 265 are inserted into through holes provided in the circuit board 123. As a result, the position of the circuit board 123 in the direction perpendicular to the central axis J1 is fixed. As a result, the horizontal position of a magnetic sensor 124 described later is accurately determined. Since the circuit board 123 does not shift in the horizontal direction, it is possible to prevent tension from acting on the conductive wire connecting the stator 122 and the circuit board 123.

  The convex portion 266 protrudes relatively outward in the radial direction when the periphery is a concave portion. As shown in FIG. 1, the convex portion 266 engages with the ring-shaped snap fit portion 151 of the cap member 15. Thereby, the cap member 15 is fixed to the insulator 232. As shown in FIG. 3, the circuit board 123 is sandwiched between the cap member 15 and the board seat 28. The cap member 15 surrounds the outer periphery of the circuit board 123. Thereby, it is possible to prevent foreign matter from entering the cap member 15 from between the cap member 15 and the circuit board 123. Although most of the side surface of the circuit board 123 is covered with the cap member 15, a part is exposed from the cap member 15.

  As shown in FIGS. 3 and 4, a coil spring 268 formed of a conductive material is inserted into one through hole 267. The coil spring 268 presses the electrodes of the core back 241 and the circuit board 123. Since the cover member 121 that is a conductive member is in direct contact with the stator core 231 that is a conductive member, the cover member 121 is electrically connected to the circuit board 123 via the stator core 231 and the coil spring 268. As a result, the circuit board 123 is grounded by grounding the cover member 121.

  In the vertical direction, the position of the upper surface of the stator core 231 coincides with the position of the upper end 227 of the outer cylindrical portion 222 of the cover member 121. Thereby, the height of the outer cylinder part 222 can be minimized without reducing the strength of fixing the stator core 231 to the outer cylinder part 222. The outer side surface 270 of the upper partial insulator 251 is located on the upper side of the outer cylinder part 222 and radially outside the inner side surface 226 of the outer cylinder part 222. Preferably, the outer side surface 270 is not positioned on the outer side in the radial direction than the outer side surface of the outer cylindrical portion 222. The outer protrusion 263 of the lower partial insulator 252 is in contact with the bottom 223 of the cover member 121 in the axial direction. The stator 122 is easily positioned by contact with the bottom 223. The lower end of the outer surface 270 of the upper partial insulator 251 and the upper end 227 of the outer cylinder part 222 are close to each other in the vertical direction. Thereby, the unevenness | corrugation of the outer surface of the motor 1 can be reduced. Note that the position of the stator 122 may be determined by bringing the lower end of the outer surface 270 into contact with the upper end 227 of the outer cylindrical portion 222.

  On the other hand, the lower end of the cap member 15 comes into contact with the outer protrusion 261 of the upper partial insulator component 250 from above. As shown in FIG. 1, the upper partial insulator component 250 is exposed radially outward on the upper side of the outer cylinder portion 222. That is, the entire region in the height direction of the motor 1 is not covered by the cover member 121 and the cap member 15. Thereby, the height of the outer cylinder part 222 becomes low compared with the motor of a comparable magnitude | size. As shown in FIG. 4, the outer protrusion 261 exists over the entire circumference in the circumferential direction. Both side portions 269 in the circumferential direction of the outer protruding portion 261 include side protrusions 272 that protrude in the circumferential direction when viewed in plan. The side protrusions 272 overlap in the radial direction from the upper end to the lower end. In other words, on the upper side of the outer cylindrical portion 222, both side portions 269 in the circumferential direction of the upper partial insulator parts 250 overlap with the adjacent upper partial insulator parts 250 in the radial direction. Thereby, in the motor 1 in which the labyrinth structure is formed and the insulator 232 is exposed, entry of dust into the inside can be suppressed.

  In addition, by providing the outer protrusion 261, the manufacturing cost can be reduced as compared with the case where the cap member 15 is attached by providing a separate spacer or the like. In the motor 1, if an attachment portion to the device is provided on the upper side, the attachment strength cannot be ensured due to the influence of the resin insulator 232. However, in the motor 1, the mounting hole 224 is provided in the bottom part 223, and the output shaft protrudes downward, so that the mounting strength can be ensured. Furthermore, by providing the circuit board 123 and the encoder 14 not on the bottom 223 but on the side opposite to the output shaft, the position of the stator 122 can be brought close to the bottom 223, and the torque generation center can be easily located between the bearing spans. Can be positioned.

  The coil 233 is formed by winding a conductive wire from above the insulator 232 around each tooth 242 in multiple layers. As shown in FIG. 3, the coil 233 is formed between the outer protrusions 261 and 263 and the inner protrusions 262 and 264 of the upper partial insulator component 250 and the lower partial insulator 252. The upper end 234 of the coil 233 is located above the upper end 227 of the outer cylinder part 222. Thereby, even if the stacked thickness of the stator core 231 is increased, it is not necessary to extend the outer cylindrical portion 222 of the cover member 121 upward. Torque is generated between the coil 233 and the rotor magnet 113 by causing a current to flow from the circuit board 123 to the coil 233. Thereby, the rotation part 11 rotates centering on the central axis J1.

  The encoder 14 includes a sensor unit 141 and a plate unit 142. The sensor unit 141 is attached to the upper surface of the circuit board 123. The plate portion 142 is perpendicular to the central axis J1 and is attached to the shaft 111. The sensor unit 141 optically detects the passage of the slit formed in the plate unit 142, whereby the rotation speed of the shaft 111 is detected. Instead of the encoder 14, an FG (Frequency Generator) pattern may be formed on the circuit board 123, and an FG magnet may be disposed on the connection portion 212 of the rotor holder 112.

  A magnetic sensor 124 is attached to the lower surface of the circuit board 123. The magnetic sensor 124 is supported by the circuit board 123 above the rotor magnet 113. The rotation position of the rotor magnet 113, that is, the rotation of the rotating unit 11 is detected by the magnetic sensor 124. In the motor 1, a Hall element is used as the magnetic sensor 124. An FG pattern formed on the circuit board 123 and supported by the circuit board 123 above the rotor magnet 113 may be used as the magnetic sensor 124.

  As described above, since the stator core 231 is formed by laminating a plurality of magnetic steel plates, when each magnetic steel plate is gradually thickened due to tolerance, the stacking thickness, which is the thickness of the stator core 231 in the direction of the central axis J1, increases. If the position of the stator in the central axis direction is determined when the stator abuts on the cover member, the upper partial insulator and the circuit board are positioned above the desired position by the thickness of the stator core. Will do. As a result, the distance in the central axis direction between the rotor magnet of the rotating part positioned with respect to the cover member and the magnetic sensor fixed to the circuit board becomes larger than the desired distance, and the rotational position of the rotor magnet The detection accuracy will be reduced.

  In the motor 1, the outer protrusion 263 of the lower partial insulator 252 contacts the bottom 223 of the cover member 121 in the direction of the central axis J <b> 1, whereby the relative position of the insulator 232 with respect to the cover member 121 in the central axis J <b> 1 direction is determined. The Thus, the relative positions of the stator 122 and the circuit board 123 with respect to the cover member 121 in the direction of the central axis J1 are determined. For this reason, it is possible to accurately position the magnetic sensor 124 with respect to the rotor magnet 113 while suppressing an influence due to an error in the thickness of the stator core 231. As a result, the magnetic sensor 124 can be disposed close to the rotor magnet 113, and the rotational position of the rotor magnet 113 can be detected with high accuracy. When the detection accuracy of the rotational position of the rotor magnet 113 is sufficiently high, an inexpensive and low-grade magnetic sensor 124 can be employed, or the height of the rotor magnet 113 in the direction of the central axis J1 can be reduced.

  The circuit board 123 may be deformed such as warpage or distortion due to mounting of the magnetic sensor 124 or other electronic components (not shown). In the motor 1, deformation of the circuit board 123 can be suppressed by holding the circuit board 123 so as to be sandwiched between the board seat 28 and the cap member 15. Thereby, the precision of the relative position with respect to the rotor magnet 113 of the magnetic sensor 124 can be improved.

  Since the circuit board 123 is fixed on the upper end surface of the outer protruding portion 261, the area of the circuit board 123 can be easily increased as compared with the case where the circuit board 123 is fixed inside the outer cylindrical portion 222. As a result, a large but low-priced electronic component can be adopted as the electronic component mounted on the circuit board 123, and the manufacturing cost of the motor 1 can be reduced. In addition, a connector (not shown) for connecting the circuit board 123 to an external power source can be easily disposed outside the motor 1 simply by providing a notch at the lower end of the cap member 15.

  FIG. A is a perspective view of the cap member 15 as viewed obliquely from above. FIG. B is a perspective view of the cap member 15 as viewed obliquely from below. The cap member 15 is formed by resin injection molding. The cap member 15 can be easily obtained by injection molding. The cap member 15 includes a snap fit portion 151, a tubular portion 152, a canopy portion 153, and an elastic portion 154. The canopy 153 covers the upper side of the circuit board 123. The canopy 153 extends in a direction perpendicular to the central axis J1. The cylindrical portion 152 extends downward from the outer edge portion of the canopy portion 153 toward the motor main body portion 10.

  The snap fit portion 151 protrudes downward from the tubular portion 152. The snap fit portion 151 is annular when viewed from the outside in the radial direction. The elastic portion 154 is adjacent to the snap fit portion 151 in the circumferential direction. The cylindrical portion 152 includes a concave portion 156 that extends downward from its upper end, that is, the canopy portion 153, and is recessed radially inward. The recess 156 is configured by a plurality of side surfaces parallel to the central axis J1. A plurality of snap-fit portions 151 having the same shape are arranged in the circumferential direction. A plurality of elastic portions 154 having the same shape are also arranged in the circumferential direction. In the present embodiment, the plurality of snap fit portions 151 are arranged at equal intervals in the circumferential direction. The plurality of elastic portions 154 are also arranged at equal intervals in the circumferential direction.

  The elastic portion 154 extends radially outward from the surface of the recess 156 at the lower end of the recess 156. By providing the elastic portion 154 in this manner, an injection mold can be easily manufactured. The elastic part 154 is located in the recess 156. By providing the recess 156, a large space in the cap member 15 can be secured. Further, by providing the concave portion 156 so as to extend in the vertical direction, the cap member 15 can be easily molded, particularly injection-molded with a resin.

  FIG. 6 is a cross-sectional view of the vicinity of the elastic portion 154 by a surface including the central axis J1. The elastic part 154 includes an arm part 161 and a contact part 162. The contact portion 162 is in contact with the upper surface of the circuit board 123. The arm portion 161 extends radially outward from the tubular portion 152 and connects the tubular portion 152 and the contact portion 162. In plan view, the root 163 of the arm portion 161 and the contact portion 162 are at different positions. The root 163 of the arm portion 161 is a boundary portion between the arm portion 161 and the cylindrical portion 152. Thereby, when the contact part 162 contacts the circuit board 123, the arm part 161 bends. That is, the elastic portion 154 is elastically deformed in contact with the upper surface of the circuit board 123. The elastic portion 154 applies a downward force to the circuit board 123 using a restoring force. As a result, the circuit board 123 is held so as to be sandwiched between the board seat portion 28 and the contact portion 162. By providing the plurality of elastic portions 154, the circuit board 123 is held more stably.

  The entire arm portion 161 is positioned above the circuit board 123. Thereby, interference with the arm part 161 and the circuit board 123 can be prevented easily. The contact portion 162 of the elastic portion 154 includes a protrusion 164 that protrudes downward and contacts the circuit board 123. In other words, the elastic portion 154 includes a protrusion 164 that protrudes downward at or near the tip. Thereby, the contact part 162 can be made to contact the circuit board 123 appropriately.

  FIG. 7 is a longitudinal sectional view of the elastic portion 154. A distance 171 between the root 163 of the arm portion 161 and the contact portion 162 in plan view is larger than the minimum width 172 of the arm portion 161 in the cross section of the arm portion 161 by a plane including the central axis J1. Here, the position of the contact portion 162 indicates the position of the center of the contact area between the contact portion 162 and the circuit board 123. In the case of the present embodiment, it refers to the center of the contact area between the protrusion 164 and the circuit board 123. With such a structure, the elastic portion 154 can be easily bent.

  As described above, the pins 265 projecting upward are provided on the upper surface of the substrate seat 28 as shown in FIG. The plurality of pins 265 are arranged in the circumferential direction. The circuit board 123 includes a plurality of through holes 126. Each pin 265 is inserted into the through hole 126. The upper surface of the pin 265 is positioned below the upper surface of the circuit board 123 in the axial direction. In other words, the height of the pin 265 from the board seat 28 is smaller than the thickness of the circuit board 123. Further, the substrate seat portion 28 and the contact portion 162 of the elastic portion 154 overlap in the vertical direction. Thereby, the structure for positioning the circuit board 123 and the structure for pressing the circuit board 123 can be spatially and efficiently arranged without causing the pins 265 and the elastic portion 154 to interfere with each other. In particular, the bending stress acting by pressing the circuit board 123 can be reduced by overlapping the board seat 28 and the contact part 162 in the vertical direction.

  2 and 5. As shown to B, the lower part of the inner peripheral part of the cylindrical part 152 contains the level | step-difference part 157 which spreads radially outward toward the downward direction. A surface 158 facing downward from the stepped portion 157 faces the upper surface of the circuit board 123. Hereinafter, the surface 158 is referred to as a “substrate facing surface”. The board facing surface 158 faces most of the outer edge of the circuit board 123. The substrate facing surface 158 is close to the upper surface of the circuit board 123, but a part or the whole may be in contact with the circuit board 123. That is, the substrate facing surface 158 is close to or in contact with the upper surface of the circuit board 123.

  In a state where the cap member 15 exists alone, the lower end of the contact portion 162 is positioned below the substrate facing surface 158. Therefore, when the cap member 15 is brought close to the motor main body 10 in the axial direction when the cap member 15 is attached to the motor main body 10, first, the contact portion 162 contacts the circuit board 123. Thereafter, the board facing surface 158 contacts or approaches the circuit board 123. The elastic portion 154 prevents the circuit board 123 from being pressed too strongly. By providing the board facing surface 158, the circuit board 123 is prevented from moving upward against the pressing by the elastic portion 154 due to an impact or the like. Most of the outer peripheral surface of the circuit board 123 is covered by the inner peripheral surface extending downward from the radially outer edge of the substrate facing surface 158.

  FIG. 8 is a diagram showing a flow of manufacturing the motor 1. In manufacturing the motor 1, first, the cover member 121 is formed by press working (step S11).

  Next, the bearing 13 is press-fitted and fixed to the inner side surface 225 of the inner cylindrical portion 221 (step S12). Further, the separately assembled stator 122 is press-fitted and fixed to the inner side surface 226 of the outer cylindrical portion 222 (step S13).

  The rotating part 11 is also assembled separately. Specifically, the shaft 111 is press-fitted and fixed to the rotor holder 112 (step S14). Then, the rotor magnet 113 is attached to the outer surface of the rotor holder 112 with an adhesive (step S15).

  The shaft 111 is inserted into the bearing 13 from above in FIG. 2 (step S16). At this time, the resin plate 214 is inserted. Thereby, the rotor magnet 113 is arranged inside the stator 122. A stopper 215 is attached to the shaft 111. The circuit board 123 is placed on the insulator 232 from above (step S17). Further, the conductor of the stator 122 and the circuit board 123 are connected. A plate portion 142 of the encoder 14 is attached to the shaft 111. A sensor unit 141 is attached to the circuit board 123.

  Finally, the cap member 15 is attached to the outer surface 270 of the outer protruding portion 261 above the outer cylindrical portion 222 (step S18). At this time, when the cap member 15 is fitted into the insulator 232 from above, the snap fit portion 151 is elastically deformed radially outward and gets over the convex portion 266. Then, at the same time that the convex portion 266 is fitted into the central hole of the snap fit portion 151, the lower end of the cylindrical portion of the cap member 15 comes into contact with the upper portion of the insulator 232, and the upper portion of the stationary portion 12 is sealed. Thus, the cap member 15 can be easily attached to the motor main body 10 by snap fitting using elastic deformation. The snap-fit reduces the number of assembly steps for the motor 1. In addition, since the cap member 15 is attached to the outer peripheral surface of the insulator 232, the structure of the motor 1 can be simplified.

  Simultaneously with the attachment of the cap member 15, the elastic portion 154 applies a downward force to the circuit board 123. As a result, the circuit board 123 is held between the elastic part 154 and the board seat part 28. Thus, in the motor 1, the number of steps for assembling the motor can be reduced as compared with the case where the circuit board 123 is fixed by welding or screwing. When fixing the circuit board 123, no adhesive or dedicated equipment is required. Further, the force acting on the circuit board 123 during assembly can be reduced as compared with the case where the circuit board 123 is fixed using snap fit. As a result, damage due to warping of the circuit board 123 can be prevented, and the reliability of the motor 1 can be improved.

  In addition, by using the elastic part 154, the elastic part 154 presses the circuit board 123 with a force of an appropriate size. Thereby, the tolerance of the thickness of the circuit board 123 and the curvature before an assembly | attachment can be enlarged. An increase in manufacturing cost of the motor 1 is suppressed.

  The present invention is not limited to the above embodiment, and may be variously modified. For example, the number of elastic portions 154 may be one. Of course, in order to suppress the warp of the circuit board 123 and stabilize the distance between the magnetic sensor 124 and the rotor magnet 113, the number of the elastic portions 154 is preferably plural.

  The arm part 161 does not need to extend radially outward, and may extend in the circumferential direction, for example. Further, the base of the arm part 161 may be connected to the canopy part 153. For example, the elastic portion 154 may extend downward from the canopy portion 153 inside the tubular portion 152. The elastic portion 154 may be a rod-shaped elastic body, a coil spring, a leaf spring, or the like. The arm portion 161 may extend downward and radially outward from the tubular portion 152 and the canopy portion 153. Thus, the arm part 161 connects the cylindrical part 152 or the canopy part 153 and the contact part 162. The arm portion 161 may extend radially inward.

  The canopy 153 need not completely cover the circuit board 123. For example, a through hole may be provided in the center of the canopy 153.

  The contact portion 162 may contact the edge of the upper surface of the circuit board 123. In the description regarding the contact between the contact portion 162 and the circuit board 123, the upper surface of the circuit board 123 includes an edge of the upper surface. As shown in FIG. 9, for example, the contact portion 162 and the circuit board 123 may be in contact with each other only at an edge that is a boundary between the through hole 126 and the upper surface. Even in this case, the upper end of the pin 265 of the board seat portion 28 and the protrusion 164 of the contact portion 162 are not in contact with each other. The contact portion 162 may be in contact with the upper surface of the circuit board 123 on a wide surface.

  The through hole 126 of the circuit board 123 may be a non-penetrating recess. A cutout may be provided instead of the through hole 126. The substrate seat 28 may be provided as a separate member from the insulator 232. For example, an annular member placed on the insulator 232 may function as the substrate seat.

  The bearing 13 may be a ball bearing. In this case, the bearing 13 is fixed to the inner cylinder part 221 with an adhesive. The bearing 13 may not be directly fixed to the cover member 121, and the bearing 13 may be indirectly fixed to the cover member 121 via another member. In addition, as for other fixing structures such as the rotor holder 112 and the shaft 111, the cover member 121 and the stator 122, indirect fixing via other members may be employed as appropriate. As the encoder 14, for example, an encoder including a cylindrical plate portion 142 centered on the central axis J1 may be used. The encoder 14 may not be attached.

  If the positional accuracy of the magnetic sensor 124 relative to the rotor magnet 113 can be sufficiently secured by causing the insulator 232 to contact the cover member 121 in the axial direction, the circuit board 123 is not necessarily provided with the cap member 15 and the upper partial insulator component. It is not necessary to be sandwiched between the upper end surfaces of the 250 outer protrusions 261. Further, if the positional accuracy of the magnetic sensor 124 relative to the rotor magnet 113 can be sufficiently secured by sandwiching the circuit board 123 between the cap member 15 and the upper end surface of the outer protrusion 261, the insulator 232 is It is not always necessary to contact the cover member 121 in the direction of the central axis J1.

  From the viewpoint of positioning the magnetic sensor 124 with respect to the rotor magnet 113 with high accuracy, the inner cylinder portion 221 of the cover member 121 does not necessarily have to be molded together with the bottom portion 223 and the outer cylinder portion 222 by pressing. For example, the inner cylinder part 221 formed of resin or the like may be press-fitted into the bottom part 223. On the other hand, from the viewpoint of reducing the manufacturing cost of the motor, it is not always necessary to position the insulator 232 in contact with the cover member 121 in the axial direction, and the circuit board 123 is positioned above the cap member 15 and the outer protrusion 261. There is no need to hold it between the end faces.

  The assembly order of the motor 1 may be variously changed within a possible range. The shaft 111 and the rotor holder 112 may be connected by being integrally formed by cutting.

  The stator core 231 may be a divided core divided for each tooth 242. An annular stator core 231 may be formed by slightly continuing adjacent divided cores on both sides and bending the arrangement of the divided cores. In this case, like the stator core 231, the plurality of upper partial insulator parts 250 and the plurality of lower partial insulators 252 may be continuous at a portion covering the core back, and may be bent annularly together with the stator core 231. The stator core 231 may be formed by stacking magnetic steel plates punched in a shape including an annular core back portion and a plurality of teeth portions extending inward from the core back portion.

  The plurality of upper partial insulator parts 250 may be prepared as one annular part. Similarly, the plurality of lower partial insulators 252 may also be prepared as one annular part.

  The outer protrusions 261 of the upper partial insulator component 250 do not need to contact each other as long as both side portions 269 overlap with the other outer protrusions 261 in the radial direction. The shape of the side portions 269 may be an uneven structure other than the side protrusions 272. The outer side surface 270 of the upper partial insulator 251 does not have to be positioned on the upper side of the outer cylindrical portion 222 and radially outside the inner side surface 226 of the outer cylindrical portion 222.

  The coil spring 268 is disposed between the stator core 231 and the circuit board 123 and can be electrically connected to the circuit board 123 and the cover member 121 by elastically deforming and pressing the stator core 231 and the circuit board 123. Other conductive elastic members may be used. For example, conductive rubber or a leaf spring can be used. In addition, a conductive elastic member is disposed between the cover member 121 and the circuit board 123. The conductive elastic member presses the cover member 121 and the circuit board 123, whereby the circuit board 123 is electrically connected to the cover member 121. Also good. Furthermore, a conductive member with poor elasticity may be used instead of the coil spring 268 as long as it can be electrically connected to the circuit board 123. That is, the circuit board 123 is electrically connected to the cover member 121 directly or indirectly through the conductive member.

  The cap member 15 does not have to be exposed to the insulator 232 by extending to the outer cylindrical portion 222. The snap fit portion 151 may also have a claw shape whose tip is bent instead of an annular shape. The motor body 10 may be provided with a snap fit portion that extends toward the cap member 15. Various forms may be adopted as a snap-fit structure for fastening the motor main body 10 and the cap member 15.

  The structure of the cover member 121, the insulator 232, the cap member 15 and the like of the motor 1 can be used for other motors such as a stepping motor. The motor 1 can be used for various devices other than office equipment.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

  The present invention can be used for motors for various purposes.

DESCRIPTION OF SYMBOLS 1 Motor 10 Motor main-body part 13 Bearing 15 Cap member 28 Board | substrate seat part 111 Shaft 112 Rotor holder 113 Rotor magnet 121 Cover member 122 Stator 123 Circuit board 126 Through-hole 151 Snap fitting part 152 Cylindrical part 153 Canopy part 154 Elastic part 156 Recessed part 158 Substrate facing surface 161 Arm portion 162 Contact portion 163 Root (of arm portion) 164 Protrusion 222 Insulator 233 Coil 265 Pin J1 Central axis

Claims (15)

A motor body,
A cap member attached to the motor body,
With
The motor body is
An annular stator centered on a central axis facing the vertical direction;
A cover member covering the outer periphery of the stator;
A bearing fixed to the cover member directly or indirectly through another member;
A shaft rotatably supported about the central axis by the bearing;
A rotor holder connected to the shaft;
A rotor magnet attached to the rotor holder and disposed inside the stator;
A circuit board located above the stator and extending in a direction perpendicular to the central axis;
A board seat located above the stator coil and in contact with the lower surface of the circuit board;
With
The cap member is
A canopy covering the top of the circuit board;
A cylindrical portion extending from the outer edge portion of the canopy portion toward the motor body portion;
An elastic portion that is elastically deformed in contact with the upper surface of the circuit board and applies a downward force to the circuit board using a restoring force;
Comprising a motor. The elastic part is
A contact portion in contact with the circuit board;
An arm portion extending from the tubular portion or the canopy portion, and connecting the tubular portion or the canopy portion and the contact portion;
With
In plan view, the base of the arm part and the contact part are at different positions,
The distance between the root of the arm part and the center of the contact area between the contact part and the circuit board in a plan view is a cross section of the arm part by a plane including the central axis. The motor according to claim 1, wherein the motor is larger than a minimum width.   The motor according to claim 2, wherein the arm portion is located above the circuit board.   4. The motor according to claim 2, wherein the substrate seat portion and the contact portion of the elastic portion overlap in a vertical direction. The board seat part is provided with a pin protruding upward,
The motor according to claim 2, wherein the circuit board includes a hole into which the pin is inserted. The upper surface of the pin is positioned axially below the upper surface of the circuit board,
The motor according to claim 5, wherein the substrate seat portion and the contact portion of the elastic portion overlap in a vertical direction.   The motor according to claim 2, wherein the contact portion includes a protrusion protruding downward.   The motor according to claim 1, wherein a plurality of elastic parts including the elastic part are arranged in a circumferential direction.   The motor according to any one of claims 1 to 8, wherein the cap member further includes a board facing surface that is close to or in contact with the upper surface of the circuit board.   The motor according to claim 1, wherein the elastic part extends radially outward. The tubular portion includes a recess that extends downward from the upper end of the tubular portion and that is recessed radially inward,
The motor according to claim 1, wherein the elastic portion extends from a surface constituting the concave portion and is located in the concave portion. The motor according to claim 1, wherein the cap member is made of resin .   The motor according to claim 1, wherein the substrate seat portion is a part of a member constituting an insulator of the stator. The cap member has a snap fit portion or a convex portion,
The motor body has the convex part or the snap fit part,
The convex portion fits into the snap fit portion,
The motor according to claim 1 , wherein the cap member is attached to the motor main body . The cap member has the snap fit portion or the convex portion,
The outer peripheral surface of the insulator has the convex portion or the snap fit portion,
The convex portion fits into the snap fit portion,
The motor according to claim 13, wherein the cap member is attached to an outer peripheral surface of the insulator .

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