JP2016140143A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of reducing an influence on a bearing in association with a change in a use environment.SOLUTION: The motor includes: a rotor (5); a bearing (4) rotatably supporting a shaft (1) of the rotor; a bearing supporting member (2) for supporting the bearing; and a fixing member (10) for fixing the bearing to the bearing supporting member. The bearing supporting member has a through-hole (2a), extending in a radial direction. The fixing member is provided in the through-hole.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric motor, and more particularly to an electric motor in which an outer ring of a bearing that rotatably supports a rotor is fixed by an adhesive.

  Conventionally, in various apparatuses such as a fundus inspection apparatus that performs optical scanning and image forming apparatuses such as a printer and a copying machine, a motor (electric motor) that reflects and deflects light output from a light beam such as a laser by a reflection mirror has been used. It has been.

  A method of printing by irradiating a plurality of lasers to one motor is the mainstream, and the mirror surface size is widened or thickened so that the laser irradiation light does not interfere with the laser. However, since the size of the apparatus is limited, it is necessary to reduce the size of the motor that drives the mirror and to extend the product life.

  Most motor bearings use ball bearings, and the mainstream is to provide a clearance fit between the outer ring of the ball bearing and the bearing housing, and to fill the adhesive with adhesive. Regarding the selection of the adhesive, an anaerobic adhesive that is efficient in assembling work is used because it is cured simply by being applied to the ball bearing outer ring or bearing housing in advance.

  However, since the bearing and the bearing housing are caught during the assembly, and the ball bearing preload amount becomes defective, in Patent Document 1, an appropriate preload is applied to the bearing and the motor is assembled. The structure which enabled it to inject | pour an adhesive agent into a ball-bearing outer ring | wheel from the hole provided in this is disclosed. Since the adhesive can be injected into the ball bearing outer ring from the hole provided on the non-load side bracket after the motor is assembled, it is possible to easily check the preload amount. Since it can be fixed, the life of the bearing can be extended and creep can be prevented.

  Further, Patent Document 2 discloses a motor that prevents a creep phenomenon by adsorbing stress due to a temperature change to the ball bearing outer ring side by a silicon adhesive layer by bonding the ball bearing outer ring and the bracket wall surface with a silicon adhesive. It is disclosed.

JP 2005-269785 A JP 2006-230083 A

  However, as the motor structure is reduced in diameter and size, ball bearings are also required to be reduced in diameter. In the prior arts such as Patent Documents 1 and 2 described above, the adhesive is spread over the entire circumference of the ball bearing outer ring and cured, and when the ball bearing outer ring is fixed in this way, it is caused by a change in use environment (temperature change). Stress is applied to the ball bearing outer ring due to the expansion and contraction of the adhesive, outer cylinder and shaft, increasing the contact resistance between the ball bearing inner ball and the inner and outer rings, causing a decrease in starting characteristics and abnormal noise, and significantly reducing motor performance. Challenges arise. Further, since the load on the ball bearing itself increases, the life of the ball bearing is shortened, resulting in a problem that the life of the motor is shortened.

  Then, an object of this invention is to provide the electric motor which can reduce the influence on the bearing accompanying the change of a use environment in view of the said subject.

  An electric motor according to an aspect of the present invention includes a rotor, a bearing that rotatably supports a shaft of the rotor, a bearing support member that supports the bearing, and a fixing member that fixes the bearing to the bearing support member. The bearing support member has a through hole extending in a radial direction, and the fixing member is provided in the through hole.

  ADVANTAGE OF THE INVENTION According to this invention, the electric motor which can reduce the influence on the bearing accompanying the change of a use environment can be provided.

It is sectional drawing of the motor in the 1st Example of this invention. It is a fragmentary sectional view of the through hole in the 1st example of the present invention. It is a fragmentary sectional view of the motor in the 2nd example of the present invention. It is a fragmentary sectional view of the through hole in the 2nd example of the present invention. It is a fragmentary sectional view of the motor in the 3rd example of the present invention. It is a fragmentary sectional view of the motor in the 1st modification of the 3rd example of the present invention. It is a fragmentary sectional view of the motor in the 2nd modification of the 3rd Example of the present invention.

  Hereinafter, embodiments to which the present invention can be applied will be described in detail with reference to the drawings. The motor according to the embodiment of the present invention exemplifies an inner rotor type DC brushless motor, and redundant description is omitted.

  FIG. 1 shows a cross-sectional view of an inner rotor type DC brushless motor (electric motor) which is an embodiment of the present invention.

  The DC brushless motor 13 includes a rotor (rotor) and a stator (stator) for rotating the rotor.

  The rotor has two shafts 1 and a cylindrical magnet 5, and the shafts 1 are respectively connected to both sides of the cylindrical magnet 5 in the axial direction (direction in which the rotation axis extends). The shaft 1 and the cylindrical magnet 5 are configured to rotate about the same rotation axis. The stator has a coil 7 and is arranged outside the rotor in this embodiment. The outer cylinder 2 is a hollow member that houses the rotor and the coil 7 therein. The load side ball bearing 3 (bearing) and the anti-load side ball bearing 4 (bearing) are attached to each of the two shafts 1 (both ends of the rotor) so as to rotatably support the shaft 1 of the rotor. The load side ball bearing 3 and the anti-load side ball bearing 4 are fixed (fixed) to the inner surface of the outer cylinder 2 together with the coil 7. In other words, the outer cylinder 2 (bearing support member) supports the coil 7 on its inner surface and supports the load side ball bearing 3 and the anti-load side ball bearing 4 (bearing). A washer 9 and a C-ring 11 for defining the position of the load-side ball bearing 3 are attached to the end of the outer cylinder 2 on the load side. A fixture 6 is attached (fixed) to the end of the outer cylinder 2 on the side opposite to the load. A preload spring 8 and a washer 9 are provided between the fixture 6 and the antiload side ball bearing 4 provided inside the outer cylinder 2, and the antiload side ball bearing 4 is preloaded by the spring pressure of the preload spring 8. Is given.

  The outer cylinder 2 is formed with a through hole 2a for injecting an adhesive (fixing member). The through-hole 2a is formed at a position overlapping the anti-load side ball bearing 4 in the radial direction of the outer cylinder 2 (direction perpendicular to the rotation axis of the rotor). At least the opening of the through hole 2 a formed on the inner surface of the outer cylinder 2 is located at a position overlapping the anti-load side ball bearing 4. That is, the anti-load side ball bearing 4 is disposed (incorporated) so as to overlap with the through hole 2 a provided in the outer cylinder 2. FIG. 2 shows a plurality of through holes 2 a (six in this embodiment) provided at equal intervals in the circumferential direction of the outer cylinder 2. As can be seen from FIG. 2, the plurality of through holes 2 a extend in the radial direction of the outer cylinder 2. In the present embodiment, the plurality of through holes 2 a extend in parallel with the radial direction of the outer cylinder 2. In the present embodiment, the width of the through hole 2 a has a constant width along the radial direction of the outer cylinder 2. The elastic adhesive 10 is a fixing member that is provided in the through hole 2 a and fixes the anti-load side ball bearing 4 to the outer cylinder 2.

  As shown in FIG. 1, the washer 9 and the C ring 11 are attached to the inner surface groove of the outer cylinder 2, thereby positioning the load side ball bearing 3 in the axial direction (direction in which the rotation axis of the rotor extends). The inner ring of the load side ball bearing 3 and the shaft 1 on the load side of the rotor are fixed. The inner ring of the other anti-load side ball bearing 4 and the shaft 1 on the anti-load side of the rotor are also fixed.

  The outer ring of the anti-load side ball bearing 4 is supported by the outer cylinder 2 in the radial direction. When the fixture 6 that supports the washer 9 and the preload spring 8 is fixed to the outer cylinder 2 by the screw 12, the preload in the axial direction is biased to both ball bearings. At this time, the rotor is rotatably supported by the two ball bearings to which the preload is urged. The elastic adhesive 10 is injected from the through-hole 2 a formed in the outer cylinder 2 after the fixture 6 is attached to the outer cylinder 2 and fixed by the screw 12. In other words, the through-hole 2a can fix the outer ring side surface of the anti-load side ball bearing 4 disposed (supported) inside the outer cylinder 2 after the fixture 6 is attached to the outer cylinder 2. As is provided.

  In the above configuration, when the elastic adhesive 10 is applied to the through-hole 2a of the outer cylinder 2 on the entire circumference of the side surface of the outer side of the ball bearing outer ring, there is a problem that the ball bearing load increases due to the expansion / contraction stress due to the temperature change of the adhesive. The injection amount needs to be kept at the same volume as the through hole 2a.

  Since the injection amount (volume) of the elastic adhesive 10 is equal to the volume (volume) of the through hole 2 a, the elastic adhesive 10 is the anti-load side ball bearing 4 corresponding to the opening shape of the through hole 2 a on the inner surface of the outer cylinder 2. Only the area is fixed (fixed). Here, the term “equal” means to include a case where it is completely equal and a case where it is deviated (ie, substantially equal) from a case where it is completely equal within the allowable error range. Therefore, the elastic adhesive 10 does not fix (adhere) the anti-load side ball bearing 4 over the entire circumference of the side surface of the outer ring of the anti-load side ball bearing 4. The elastic adhesive 10 fixes (fixes) a part (only) of the side surface of the outer ring of the anti-load side ball bearing 4. In other words, since the elastic adhesive 10 is not applied to the entire circumference of the outer ring side surface of the anti-load side ball bearing 4, it is possible to reduce the problem that the ball bearing load increases due to the expansion / contraction stress due to the temperature change of the adhesive.

  In this embodiment, the ball bearing thickness is 2.6 mm, the through hole φ1.2 mm, the adhesive 10 has a viscosity of 100 Pa · s of silicon adhesive, and the applied amount is 1.3 mg, so that the injection amount is about the same as the through hole. Keeped in volume.

  The elastic adhesive 10 is not limited to a silicon-based adhesive, and a rubber-based, vinyl-based, or urethane-based adhesive may be used.

  Next, the form of the 2nd Example of this invention is demonstrated. In the first embodiment, the through hole 22a extends in parallel with the radial direction of the outer cylinder 2 in the first embodiment, whereas the through hole 22a extends in the radial direction as shown in FIG. It is inclined and extended. In the present embodiment, the width of the through hole 22a has a constant width along the radial direction of the outer cylinder 2. FIG. 4 shows through-holes 22a provided in a plurality (six in this embodiment) at equal intervals in the circumferential direction of the outer cylinder 2.

  In order to make it difficult for stress of the adhesive to be applied to the ball bearing, a through hole 22a having a shape that allows the adhesive to escape outward is formed, and a plurality of through holes 22a are formed as shown in FIG.

  With the above configuration, even if the ambient temperature changes, the elastic adhesive layer can accept and absorb the expansion and contraction stress on the side of the outer ring, and the change in preload can be reduced. Without using the motor, it is possible to provide a motor (electric motor) that has a simple structure and reduces the influence on the motor characteristics due to temperature change.

  Next, the form of the 3rd Example of this invention is demonstrated. The through hole 42a of the third embodiment has a constant width in the first and second embodiments, whereas the width of the through hole 42a is a diameter as shown in FIG. It is changing along the direction. Specifically, the width of the through hole 42a changes so as to become narrower from the outer surface of the outer cylinder 2 toward the inner surface. The through hole 42a of the present embodiment has a concave portion 42aa (first concave portion) having a constant first width from the outer surface to the inner surface of the outer cylinder 2, and a constant second width narrower than the first width. And a concave portion 42ab (second concave portion) having a width of.

  Usually, since the management of the adhesive application amount is performed including the pressure of the application device, the application time, the tip diameter of the applicator, and the viscosity of the adhesive, the management method becomes complicated. Therefore, as shown in FIG. 5, the through-hole 42a has a stepped shape, that is, a hexagon socket head bolt shape, and a counterbore diameter shape having a seating surface, so that a hole volume corresponding to a predetermined amount is obtained in advance. By providing a structure that overflows the hole in the foreground when the specified amount is exceeded, an adhesion amount exceeding the specified amount is not applied, and stress is not applied to the ball bearing more than necessary.

  Further, the shape of the through hole 42a is not limited to the counterbore shape shown in FIG. Here, a modification of the third embodiment is shown in FIGS. FIG. 6 shows a first modification of the third embodiment, and FIG. 7 shows a second modification of the third embodiment. In the first modification of the third embodiment, as shown in FIG. 6, the outer cylinder 2 includes a through hole 52a having a tapered shape. Specifically, the outer cylinder 2 includes a conical through hole 52a. Further, in the second modification of the third embodiment, as shown in FIG. 7, the outer cylinder 2 is formed from the first width to the inner width from the outer surface to the inner surface of the outer cylinder 2. A through hole 62a having a recess 62aa (first recess) having a tapered shape that changes to a narrow second width and a recess 62ab (second recess) having a constant second width is provided. Specifically, the outer cylinder 2 includes a countersunk conical through hole 62a.

  Thus, the counterbore-shaped through hole 42a shown in FIG. 5 may be a conical through hole 52a having a taper shape as shown in FIG. 6, or a countersunk screw through hole 62a as shown in FIG. It is good.

  As described above, according to the above embodiment, the ball bearing inner ring side is fixed integrally with the rotating shaft and the ball bearing outer ring side is held by the elastic adhesive in the through hole, so that the use environment (temperature) changes. Even so, the elastic adhesive layer can allow and absorb the expansion and contraction stress to the outer ring side surface. Therefore, the motor load does not increase even in a low temperature environment, and the influence on motor characteristics due to temperature changes is reduced with a simple structure without using special bearings or structures as the bearings become smaller. Can provide a long-life motor. As described above, according to the present invention, it is possible to provide a motor (electric motor) capable of reducing the influence on the bearing due to a change in use environment (temperature).

  In the above embodiment, the ball bearing is used for the description of the bearing. However, it may be a rolling bearing such as a cylindrical roller, a conical roller, a self-aligning roller, or a roller bearing, or a bearing such as a slide bearing, a magnetic bearing, or a fluid bearing. But you can.

  Each embodiment described above is only a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

  The motor of the present invention can be suitably used for various apparatuses such as a fundus inspection apparatus that performs optical scanning, and image forming apparatuses such as printers and copiers.

DESCRIPTION OF SYMBOLS 1 Shaft 2 Outer cylinder 2a, 22a, 42a, 52a, 62a Through-hole 3 Load side ball bearing (load side bearing)
4 Anti-load side ball bearing (anti-load side bearing)
5 Magnet 6 Mounting tool 7 Coil 8 Preload spring 9 Washer 10 Elastic adhesive 11 C ring 12 Screw 13 Motor

Claims (17)

A rotor,
A bearing rotatably supporting the shaft of the rotor;
A bearing support member for supporting the bearing;
A fixing member for fixing the bearing to the bearing support member;
Have
The bearing support member has a through hole extending in a radial direction,
The fixing member is provided in the through hole,
An electric motor characterized by that.   The electric motor according to claim 1, wherein the fixing member fixes an area of the bearing corresponding to an opening shape of the through hole on an inner surface of the bearing support member.   The electric motor according to claim 1, wherein the fixing member does not fix the bearing over the entire circumference of the bearing.   4. The electric motor according to claim 1, wherein the through hole is disposed so as to overlap the bearing in the radial direction. 5.   5. The electric motor according to claim 1, wherein the bearing support member supports a stator for rotating the rotor. 6.   The electric motor according to claim 1, wherein the through hole extends in parallel with the radial direction.   The electric motor according to claim 1, wherein the through hole extends while being inclined with respect to the radial direction.   8. The electric motor according to claim 1, wherein a width of the through hole has a constant width along the radial direction. 9.   The electric motor according to claim 1, wherein a width of the through hole changes along the radial direction.   The electric motor according to claim 9, wherein a width of the through hole is narrowed from an outer surface to an inner surface of the bearing support member.   The through hole has a first concave portion having a constant first width from the outer surface to the inner surface of the bearing support member, and a second second width having a constant second width narrower than the first width. The electric motor according to claim 10, further comprising a recess.   The electric motor according to claim 10, wherein the through hole has a tapered shape.   The through hole includes a first recess having a tapered shape that changes from a first width to a second width that is narrower than the first width from the outer surface toward the inner surface of the bearing support member, The electric motor according to claim 10, further comprising a second concave portion having a second width.   14. The electric motor according to claim 1, wherein the bearing support member has a plurality of the through holes provided at equal intervals in a circumferential direction.   The electric motor according to claim 1, wherein the fixing member is an elastic adhesive.   The electric motor according to claim 15, wherein the elastic adhesive is a silicon-based, rubber-based, vinyl-based, or urethane-based adhesive. 17. The electric motor according to claim 1, wherein a volume of the fixing member is equal to a volume of the through hole.