JP4597015B2 - motor - Google Patents

Description

  The present invention relates to a motor. More specifically, the present invention relates to a structure of a pressurizing member that biases a bearing supporting one shaft end of the rotating shaft toward the rotating shaft.

As shown in FIG. 5, a stepping motor used for a digital camera, a digital video camera, an FDD, an ODD, etc. generally has a rotor 105 inside a rotor arrangement hole 130 that opens in a motor axial direction L ′ in a cylindrical stator 140. Is arranged, and one end of the rotating shaft 151 is supported by a bearing 107 via a sphere 170. Here, the bearing 107 is inserted into the through hole 180 of the bearing holder 108, and is directed toward the rotating shaft 151 by the leaf spring portion 190 of the pressurizing member 109 disposed further on the one end side than the bearing holder 108. Is energized. Here, the leaf spring portion 190 is bent in the middle portion on the side opposite to the rotating shaft 151, and a corner portion 196 formed by such bending is in contact with a portion through which the motor axis L ′ passes in the bearing 107. (See Patent Document 1).
JP 2003-299298 A

  In such a motor, a tolerance is set between the through hole 180, the inner diameter dimension, and the outer dimension of the bearing 107, and a dimensional difference greater than the tolerance may occur. In any of these cases, since there is a gap between the inner peripheral surface of the through hole 180 and the outer peripheral surface of the bearing 107, when the rotor 105 rotates, the bearing 107 may rattle in the through hole 180. Such shakiness causes abnormal noise and shake of the rotating shaft 151. Such a problem is particularly prominent when the bearing 107 is formed of a resin molded product, because variations in outer dimensions of the bearing 107 are likely to occur due to sink marks during molding.

  In view of the above problems, an object of the present invention is to propose a motor capable of appropriately applying a pressure to a bearing and preventing rattling of the bearing in a through hole of the bearing holder.

In order to solve the above-mentioned problems, in the present invention, a cylindrical stator having a rotor arrangement hole that opens in the motor axial direction, a rotor arranged in the rotor arrangement hole, and one of the rotation axes of the rotor A bearing that supports the end, a bearing holder that includes a through hole in which the bearing is mounted, and a leaf spring portion that is further disposed on one end side than the bearing holder and biases the bearing toward the rotating shaft In a motor having a pressurizing member made of a metal plate cut and raised on the bearing side,
The bearing supports one shaft end of the rotating shaft via a sphere disposed between the shaft ends or a sphere formed at the shaft end,
The leaf spring portion abuts at a position where a corner portion formed by cutting and raising a middle portion in the length direction and bending the portion in the opposite direction to the direction avoids a portion where the motor axis passes in the bearing. However, the inside of the through hole is held in a state inclined with respect to the motor axis .

  In this invention, the leaf | plate spring part urges | biases the bearing arrange | positioned in the through-hole of a bearing holder toward a rotating shaft, and is providing the pressurization. In addition, the leaf spring portion abuts on the bearing in a region avoiding the portion through which the motor axis passes in the bearing, and is biased. For this reason, since the bearing is held in a state inclined with respect to the motor axis by an amount corresponding to the gap dimension with the inner peripheral surface of the through hole, the bearing does not rattle. Therefore, the generation of abnormal noises due to the shakiness of the bearing and the vibration of the rotating shaft do not occur. Further, in the present invention, the leaf spring portion has a corner portion formed by cutting and raising a middle portion in the length direction and bending it to the opposite side with respect to the direction, and the corner portion has an edge. Absent. For this reason, the edge of a leaf | plate spring part does not bite into a bearing. In particular, when burrs or burrs protrude from the edge of the leaf spring portion on the side where the bearings are arranged, burrs and burrs will bite into the bearings. Does not occur. Therefore, the leaf spring portion does not prevent the bearing from being tilted in the through hole, so that the bearing can be held in a suitable posture in the through hole, and the pressurization is appropriately applied.

  The present invention is particularly effective when applied to the case where the bearing is made of resin. When the bearing is made of resin, the outer dimensions of the bearing vary due to sink marks when molding it, and a large difference is likely to occur between the outer diameter of the bearing and the inner diameter of the through hole. Even in such a case, the bearing is biased by the leaf spring portion and held in a state of being inclined in a suitable posture within the through hole. For this reason, since the bearing does not rattle in the through hole, no abnormal noise is generated and the rotating shaft does not shake. Furthermore, when the bearing is made of resin, the burrs, burrs, or edges of the leaf spring portion are likely to bite into the bearing. However, according to the present invention, the bent portion of the leaf spring portion is in contact with the bearing, so the bite Does not occur.

  In the present invention, the leaf spring portion is bent at a position closer to the motor axis as viewed from the root portion, and the corner portion is positioned on the same side as the root portion with respect to the motor axis. However, it is preferable that the leaf spring portion is bent at a position far from the motor axis when viewed from the root portion, and the corner portion is located on the opposite side of the motor shaft line from the root portion. When the latter configuration is adopted, the leaf spring portion can be configured to have a sufficient length, so that the leaf spring portion having a predetermined urging force can be configured simply by raising the metal plate.

  In this invention, it is preferable that the front end side of the said leaf | plate spring part is provided with the substantially semicircular planar shape. If comprised in this way, since the distortion which generate | occur | produces when bending a leaf | plate spring part is small, a corner | angular part can be formed linearly and a bearing can be pressed in the whole corner | angular part.

  In this invention, the leaf | plate spring part of a pressurization provision member is bend | folded by the front-end | tip part, and the bearing in a through-hole is pressed toward the axial end of a rotating shaft by this bent corner | angular part. Since the corner portion is pressed against the bearing, the leaf spring portion is in line contact with the bearing. In addition, there are no burrs or burrs at the corners. Therefore, in the state where the bearing in the through hole is pressed toward the shaft end of the rotating shaft by the leaf spring portion, the pressurizing direction of the leaf spring portion with respect to the bearing does not shift. Therefore, according to the present invention, since the pressurizing direction of the leaf spring portion with respect to the bearing does not shift, the bearing can be reliably held at a predetermined position in the through hole, and the position of the bearing in the through hole can be defined with high accuracy. Can do. Therefore, the rotor can be rotated in a stable state.

  An example of a motor to which the present invention is applied will be described below with reference to the drawings.

(overall structure)
FIG. 1 and FIG. 2 are a longitudinal sectional view of a stepping motor to which the present invention is applied, and an exploded perspective view showing an essential part thereof exploded. As shown in these drawings, the motor 1 of the present embodiment is a small stepping motor used in a digital camera, a digital video camera, an FDD, an ODD, and the like. In the stator 40, an annular first coil around which a coil 25 is wound is provided. One bobbin 2A and the second bobbin 2B are arranged so as to overlap in the motor axis L direction. An annular inner stator core 3A and an outer stator core 4A are disposed on both sides of the first bobbin 2A in the motor axis L direction, and an annular inner stator core 4A is disposed on both sides of the second bobbin 2B in the motor axis L direction. The stator core 3B and the outer stator core 4B are arranged so as to overlap each other, and on the inner peripheral surfaces of the first bobbin 2A and the second bobbin 2B, a plurality of pole teeth 31 and 41 of the inner stator cores 3A and 3B and the outer stator cores 4A and 4B. Are arranged in the circumferential direction. Thus, the cylindrical stator 40 provided with the rotor arrangement | positioning hole 30 is comprised, and the base end side of the rotor 5 is coaxially arrange | positioned inside this rotor arrangement | positioning hole 30. FIG. The rotor 5 includes a rotor magnet 52 around the base end side of the rotation shaft 51, and the rotor magnet 52 is arranged inside the rotor arrangement hole 30 with a predetermined distance from the pole teeth 31 and 41 of the stator. Opposite.

  In this embodiment, a cylindrical case 10 is constituted by outer peripheral portions of the outer stator cores 4A and 4B, and the stator 40 including the coil 25, the inner stator cores 3A and 3B, and the outer stator cores 4A and 4B inside the case 10 The base end side of the rotor 5 is arranged.

  A plate 6 is fixed to the front end surface of the outer stator core 4B constituting the case 10, and the rotating shaft 51 of the rotor 5 is supported by a thrust bearing 61 held at a bent portion on the front end side of the plate 6. ing.

  The rotary shaft 51 has a shaft end 53 on one end side (the first bobbin 2 </ b> A side) in the direction of the motor axis L supported by the bearing 7 via a steel ball 70, and the steel ball 70 is recessed at the shaft end 53. The concave portion 530 provided with the conical surface and the concave portion 71 provided with the concave conical surface in the bearing 7 are held. A plate-like bearing holder 8 made of a sintered body or the like is disposed on one end side with respect to the stator 40 so as to at least partially overlap the stator 40. It is mounted in the through hole 80. Here, the bearing 7 is in a state of being movable in the direction of the motor axis L inside the through hole 80. The bearing holder 8 is fixed to the outer stator core 4A by a method such as spot welding, and in order to perform such spot welding, in this embodiment, the bottom plate portion 42 of the outer stator core 4A is used for welding the bearing holder 8. The four end projections 45 (projections) are formed, while the bearing holder has a flat end surface facing the projections 45 (bottom plate portion 42). Accordingly, when assembling the motor 1, the bearing holder 8 is brought into contact with the four protrusions 45 of the outer stator core 4A in the positioning state, and these currents are supplied while the bearing holder is pressed against the protrusion 45. By performing spot welding on each of the protrusions 45, the bearing holder 8 is fixed to the outer stator core 4A.

  In this embodiment, a pressurizing member 9 made of a metal plate is disposed on one end side further than the bearing holder 8 so as to at least partially overlap the bearing holder 8. The four claw portions 95 extending from the shaft to the bearing holder 8 are fixed to the bearing holder 8 by engaging with the outer peripheral edge of the bearing holder 8. Further, in the pressurizing member 9, the leaf spring portion 90 is cut and raised toward the bearing 7, and the leaf spring portion 90 urges the bearing 7 in the through hole 80 toward the rotating shaft 51 to apply pressure. Pressure is applied.

(Configuration of leaf spring 90)
3 (a) to 3 (c) are a plan view showing a pressurizing member of the stepping motor shown in FIG. 1, a longitudinal sectional view of a portion cut along line II ′, and a sectional view of a leaf spring portion. is there. As shown in FIGS. 1, 2, and 3 (a) to 3 (c), the pressurizing member 9 is a pressed product of a metal plate, and bearings are provided from four locations on the outer peripheral edge of the end plate portion 91. Four engaging claws 95 are formed which wrap around the outer peripheral side surface of the holder 8 and engage with engaging concave portions formed on the outer peripheral edge.

  Moreover, in the center part of the end plate part 91, the leaf | plate spring part 90 is diagonally cut and raised by the side in which the bearing 7 is located by the U-shaped cutting part. Further, the leaf spring portion 90 is bent to the opposite side with respect to the cut-and-raised direction at an intermediate portion in the length direction. Therefore, the leaf spring portion 90 includes a root portion 910 connected to the end plate portion 91, a corner portion 920 formed by bending, and a tip portion 930 having a semicircular planar shape on the tip side from the corner portion 920. In this embodiment, the corner portion 920 is in contact with the end surface of the bearing 7. Here, the root portion 910 is linearly cut and raised obliquely from the end plate portion 91 and is in a state before the pressurizing member 9 is assembled into the motor 1, and the tip portion 930 is about 30 with respect to the root portion 910. It has an angle of °.

  Further, the corner portion 920 is in contact with a position in the bearing 7 that avoids a portion where the motor axis L passes. Here, since the leaf spring portion 90 is bent at a position far from the motor axis L when viewed from the root portion 910, the corner portion 920 is located on the opposite side of the root portion 910 with respect to the motor axis L.

(Operation of this form, main effect)
With reference to FIG. 4, the operation and effect of the motor of this embodiment will be described. FIG. 4 is a cross-sectional view showing a state in which the bearing is inclined in the through hole of the bearing holder in the stepping motor shown in FIG.

  In the motor 1 of the present embodiment, the bearing 7 is a resin molded product, and a tolerance is set between the inner diameter dimension of the through hole 80 and the outer dimension of the bearing 7, and due to sink marks during molding. The outer dimensions of the bearing 7 vary, and a gap greater than the tolerance is generated between the inner diameter of the through hole 80 and the outer dimension of the bearing 7. However, in this embodiment, the leaf spring portion 90 abuts on the bearing 7 in an area where a portion where the motor axis L passes in the bearing 7 is avoided and is biased. For this reason, the bearing 7 is held in a state inclined with respect to the motor axis L by an amount corresponding to the size of the gap generated between the inner peripheral surface of the through hole 80. For this reason, since the bearing 7 does not rattle in the through hole 80 when the rotor 5 rotates, no abnormal noise is generated.

  Further, when the bearing 7 is tilted in the through hole 80, the bearing 7 is tilted so as to rotate around the steel ball 70. Therefore, even if the bearing 7 is tilted, the steel ball 70 is not displaced, and the central axis L71 of the steel ball 70 is , Coincides with the motor axis L. That is, before and after the bearing 7 is tilted, the motor axis L is neither displaced nor tilted, so that the rotating shaft 51 does not swing when the rotor 5 rotates.

  Further, in the present embodiment, the leaf spring portion 90 has a corner portion 920 formed by being bent at an intermediate portion abutting the bearing 7, and the corner portion 920 has no edge, and the edge is formed during press molding. There are no burrs and burrs that have occurred. For this reason, since the situation where the edge of the leaf | plate spring part 90, the burr | flash | burr which generate | occur | produced at the edge, and a crack bite into the bearing 7 does not generate | occur | produce, the leaf | plate spring part 90 applies an appropriate pressurization to the bearing 7. FIG. Further, since the situation where the edge of the leaf spring portion 90 and the burrs and burrs generated at the edge are caught and caught in the bearing 7 does not occur, the bearing 7 is not prevented from tilting in the through hole 80. The bearing 7 can be held in a suitable posture in the through hole 80. That is, when the bearing 7 is tilted in the through hole 80, the contact position of the leaf spring portion 90 with respect to the bearing 7 is shifted, but in this embodiment, the corner portion 920 is in contact with the end surface of the bearing 7, Since such a shift occurs smoothly, the bearing 7 is not prevented from tilting in the through hole 80.

  Particularly in this embodiment, since the bearing 7 is made of resin, the outer dimensions of the bearing 7 vary due to sink marks or the like when the bearing 7 is molded, and the outer diameter dimension of the bearing 7 and the inner diameter dimension of the through hole 80 are different. Even in such a case, according to the present embodiment, the bearing 7 is biased by the leaf spring portion 90 and is held in a state of being inclined in a suitable posture within the through hole 80. Therefore, the bearing 7 does not rattle in the through-hole 80, no abnormal noise is generated, and the rotating shaft 51 does not tilt. In addition, when the bearing 7 is made of resin, the edge of the leaf spring portion 90 and burrs and burrs formed on the edge are likely to bite, but according to this embodiment, the corner portion 920 of the leaf spring portion 90 is a bearing. 7 is in contact with 7, so that no biting occurs. Therefore, even when the bearing 7 made of a resin molded product is used, it is possible to appropriately apply a pressurized pressure and to reliably prevent the bearing 7 from rattling.

  Further, in this embodiment, the leaf spring portion 90 is bent at a position far from the motor axis L as viewed from the root portion 910, so that the corner portion 920 is located on the opposite side of the root portion 910 with respect to the motor axis L. ing. For this reason, since the leaf | plate spring part 90 is long, even when the leaf | plate spring part 90 is formed by cutting and raising, the leaf | plate spring part 90 with predetermined | prescribed elasticity can be formed.

  Further, in the present embodiment, in the pressurizing member 9, since the leaf spring portion 90 is cut and raised by the U-shaped cutting portion, the tip portion 930 has a semicircular shape. For this reason, since the distortion | strain at the time of bending the leaf | plate spring part 90 is small, the corner | angular part 920 can be formed linearly and the bearing 7 can be pressed by the whole corner | angular part 920.

(Other embodiments)
In the above configuration, in the pressurizing member 9, since the leaf spring portion 90 is cut and raised by the U-shaped cutting portion, the shape of the tip portion 930 was semicircular, but as shown in FIG. In the pressure application member 9, the leaf spring portion 90 may be cut and raised by a U-shaped cutting portion, and the tip portion 930 may be formed in the rectangular leaf spring portion 90. Also in this case, it is preferable to add R to the corner portion.

  Further, in the above embodiment, the leaf spring portion 90 is bent at a position far from the motor axis L when viewed from the root portion 910, so that the corner portion 920 is located on the opposite side of the root portion 910 with respect to the motor axis L. However, a configuration in which the leaf spring portion 90 is bent at a position closer to the motor axis L when viewed from the root portion 910 may be adopted.

  Further, in the above embodiment, the bearing 7 supports the shaft end 53 of the rotating shaft 51 via the steel ball 70. However, a ball portion is formed on the shaft end 53 itself of the rotating shaft 51, and this ball portion is interposed therebetween. The present invention may be applied to a motor in which the bearing 7 supports the rotating shaft 51.

  Needless to say, the present invention can also be applied to motors other than stepping motors.

It is a longitudinal cross-sectional view of the stepping motor to which this invention is applied. It is a disassembled perspective view which decomposes | disassembles and shows the principal part of the stepping motor shown in FIG. (A) thru | or (d) is a top view which shows the pressurization provision member of the stepping motor shown in FIG. 1, the longitudinal cross-sectional view of the part cut | disconnected by the II 'line | wire, sectional drawing of a leaf | plate spring part, and leaf | plate spring It is explanatory drawing which shows the modification of a part. In the stepping motor shown in FIG. 1, it is sectional drawing which shows a mode that the bearing inclined in the through-hole of a bearing holder. It is sectional drawing which shows the principal part of the conventional stepping motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 5 Rotor 7 Bearing 8 Bearing holder 9 Pressurizing member 40 Stator 51 Rotating shaft 53 Rotating shaft end 70 Steel ball 80 Through hole 90 Leaf spring portion 910 Root portion 920 Corner portion 930 Tip portion

Claims (4)

A cylindrical stator having a rotor arrangement hole that opens in the motor axial direction, a rotor arranged in the rotor arrangement hole, a bearing that supports one shaft end of the rotation shaft of the rotor, and the bearing is mounted. A bearing holder provided with a through hole, and a metal plate disposed further on one end side than the bearing holder and energizing the bearing toward the rotating shaft. In a motor having a pressurizing member,
The bearing supports one shaft end of the rotating shaft via a sphere disposed between the shaft ends or a sphere formed at the shaft end,
The leaf spring portion abuts at a position where a corner portion formed by cutting and raising a middle portion in the length direction and bending the portion in the opposite direction to the direction avoids a portion where the motor axis passes in the bearing. Is held in an inclined state with respect to the motor axis within the through hole .   The motor according to claim 1, wherein the bearing is made of resin. In claim 1 or 2,
The motor is characterized in that the leaf spring portion is bent at a position far from the motor axis when viewed from the root portion, and the corner portion is located on the opposite side of the motor shaft line from the root portion. In any of claims 1 to 3,
The front end side of the leaf spring portion has a substantially semicircular planar shape.

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