JP2018129921A - motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor capable of suppressing occurrence of abnormal noise.SOLUTION: A motor case 10 of a motor 1 has a yoke housing 40 and an end frame 50. The yoke housing 40 has a bearing accommodating portion 44 for accommodating a first ball bearing 71, and one O-ring 80 is disposed between the bearing accommodating portion 44 and the first ball bearing 71. The end frame 50 has a bearing accommodating portion 53 into which a second ball bearing 72 is fitted. The bearing accommodating portion 44 includes: a cylindrical holding portion 44b which is in contact with the O ring and holds the first ball bearing 71; and an enlarged diameter portion 44c which is positioned closer to the side of the bearing accommodating portion 53 than the holding portion 44b and is diameter-enlarged than the holding portion 44b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor.

  Conventionally, as described in Patent Document 1, for example, a motor includes a rotor housed in a motor housing, and a rotor shaft supported by a pair of ball bearings supported by the motor housing. There is. In the motor described in Patent Document 1, two O-rings as cushioning materials are interposed in the gap between the outer peripheral surface of the ball bearing and the motor housing. Each of these O-rings is mounted in two grooves formed in an annular shape along the circumferential direction on the outer peripheral surface of the ball bearing. The ball bearing is supported by the motor housing via each O-ring. Thereby, the vibration in the radial direction of the rotor is absorbed and suppressed by the respective O-rings, so that the motor housing is suppressed from being vibrated by the vibration in the radial direction of the rotor.

JP 2008-67552 A

By the way, in the above motors, there is a possibility that abnormal noise may occur. For this reason, it is required to suppress the generation of abnormal noise.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor capable of suppressing the generation of abnormal noise.

  A motor that solves the above problems includes a motor case having a first bearing housing portion and a second bearing housing portion, and a rotating shaft having an output end portion that outputs rotation to one end portion in the axial direction, A rotor disposed inside the motor case, a first ball bearing that is housed in the first bearing housing portion and rotatably supports the rotating shaft, and is fitted into the second bearing housing portion. A second ball bearing that rotatably supports the rotating shaft, and an O-ring having elasticity and in contact with both the first ball bearing and the first bearing housing portion. And the first bearing housing portion is a cylindrical holding portion that is in contact with the O-ring to hold the first ball bearing, and is closer to the second bearing housing portion than the holding portion. And a diameter-enlarged portion that is larger than the holding portion.

  According to this configuration, the vibration in the radial direction of the rotor is absorbed and suppressed by one O-ring disposed between the first ball bearing and the first bearing housing portion. The first bearing housing portion has a diameter-expanded portion that is larger in diameter than the holding portion with which the O-ring contacts, and the contact between the first ball bearing and the first bearing housing portion is prevented by the diameter-increased portion. The generation of abnormal noise is suppressed.

  In the above motor, the first ball bearing is disposed between the outer ring and the inner ring, a cylindrical outer ring, an inner ring disposed on the inner side of the outer ring and fitted with the rotation shaft. A row of balls arranged in a circumferential direction, and a holding groove in which the O-ring is arranged on the outer peripheral surface of the outer ring on the end side of the rotating shaft from the center of the ball Is preferably formed over the entire circumference.

  According to this configuration, the outer ring of the first ball bearing is thicker on the end side than the portion located at the center of the ball. Therefore, it is easy to form a holding groove for arranging the O-ring at a position shifted from the center of the ball.

  In the motor described above, a portion of the rotating shaft between the first ball bearing and the second ball bearing has a rotor core around which a winding is wound, and a commutator connected to the winding. It is preferable that the commutator is provided between the rotor core and the second ball bearing.

  According to this configuration, the second ball bearing fitted in the second bearing housing portion is less likely to vibrate than the first ball bearing. Since the commutator is provided between the rotor core and the second ball bearing, the commutator can be disposed closer to the second ball bearing, so that vibration of the commutator can be suppressed. As a result, the sliding contact mode between the commutator and the power supply brush is stabilized, which can contribute to the improvement of the motor performance.

  According to the motor of this invention, generation | occurrence | production of abnormal noise can be suppressed.

1 is a schematic cross-sectional view of a motor according to an embodiment. (A) and (b) are expanded sectional views showing a part of motor of a comparative example roughly. (A) and (b) are expanded sectional views showing a part of another motor roughly. The schematic sectional drawing of another motor.

Hereinafter, an embodiment will be described.
As shown in FIG. 1, the motor 1 of this embodiment is a DC motor. The motor 1 includes a motor case 10, a rotor 20 (armature) and a brush device 30 housed in the motor case 10.

For example, the motor 1 is a 4-pole 22-slot motor, and the winding is wound by distributed winding and has four brushes.
The motor case 10 has a yoke housing 40 and an end frame 50. The yoke housing 40 is made of a magnetic material.

  The yoke housing 40 has a circular bottom 41 and a cylindrical side wall 42 extending in the axial direction (leftward in FIG. 1) from the outer periphery of the bottom 41, and is opposite to the bottom 41 in the axial direction. It has a bottomed cylindrical shape having an opening 43 at the end. A bearing housing portion 44 is formed at the center portion in the radial direction of the bottom portion 41 so as to protrude outward in the axial direction (right side in FIG. 1).

  The bearing housing portion 44 includes a circular housing bottom portion 44a, a cylindrical holding portion 44b extending in the axial direction (left and right direction in FIG. 1) from the outer peripheral edge of the housing bottom portion 44a, and the holding portion 44b and the bottom portion 41 of the yoke housing 40. And an enlarged-diameter portion 44c therebetween. The holding portion 44b has a uniform inner diameter in the axial direction (left-right direction in FIG. 1). The enlarged diameter portion 44c is formed such that at least the inner diameter of the end portion on the bottom 41 side of the yoke housing 40 is larger than the inner diameter of the holding portion 44b. In the present embodiment, the enlarged diameter portion 44 c is formed in a tapered shape in which the inner diameter gradually increases from the holding portion 44 b to the bottom portion 41 of the yoke housing 40.

A field magnet 60 is fixed to the inner peripheral surface of the side wall portion 42.
A first ball bearing 71 that rotatably supports the base end portion 21 a of the rotating shaft 21 of the rotor 20 is accommodated in the bearing accommodating portion 44.

  The first ball bearing 71 includes a cylindrical outer ring (outer race) 71a, a cylindrical inner ring (inner race) 71b disposed inside the outer ring 71a, and a plurality of first ball bearings 71 interposed between the outer ring 71a and the inner ring 71b. Ball 71c. The plurality of balls 71 c are arranged in a line along the circumferential direction of the first ball bearing 71. In FIG. 1, two of the plurality of balls 71c are shown. The inner ring 71 b is fitted with the base end 21 a of the rotating shaft 21, and the inner peripheral surface of the inner ring 71 b is in close contact with the outer peripheral surface of the rotating shaft 21.

  One elastic O-ring 80 is disposed between the first ball bearing 71 and the bearing housing portion 44. Specifically, the O-ring 80 is disposed between the outer ring 71 a of the first ball bearing 71 and the holding portion 44 b of the bearing housing portion 44. The O-ring 80 is made of, for example, NBR (nitrile rubber).

  In the present embodiment, one holding groove 71 d extending along the circumferential direction is formed on the outer peripheral surface of the outer ring 71 a of the first ball bearing 71. The holding groove 71d is formed so as to extend over the entire circumference of the outer ring 71a. The holding groove 71d is formed at a position shifted in the axial direction of the rotary shaft 21 from the center of the ball 71c. In the present embodiment, the holding groove 71d is formed at a position shifted from the center of the ball 71c toward the base end 21a of the rotating shaft 21. An O-ring 80 is disposed in the holding groove 71d.

  An end frame 50 that substantially closes the opening 43 is assembled to the opening 43 of the yoke housing 40. The end frame 50 includes a circular bottom 51 and a side wall 52 extending in the axial direction from the outer peripheral edge of the bottom 51. The side wall portion 52 of the end frame 50 is fixed to the flange portion 45 extending in the radial direction from the opening 43 of the yoke housing 40 by screws 91. A bearing housing 53 is recessed in the axially inner side at the center of the bottom 51 of the end frame 50.

The bearing housing 44 houses a second ball bearing 72 that rotatably supports a portion of the rotating shaft 21 near the tip 21b.
The second ball bearing 72 includes a cylindrical outer ring (outer race) 72a, a cylindrical inner ring (inner race) 72b disposed inside the outer ring 72a, and a plurality of second ball bearings 72 interposed between the outer ring 72a and the inner ring 72b. Ball 72c. The plurality of balls 72 c are arranged in a line along the circumferential direction of the second ball bearing 72. In FIG. 1, two of the plurality of balls 72c are shown.

  The second ball bearing 72 is fitted into the bearing housing portion 53 (may be a clearance fit or a tight fit). That is, the outer peripheral surface of the outer ring 72 a of the second ball bearing 72 is in close contact with the inner peripheral surface of the bearing housing portion 53. The rotating shaft 21 is fitted to the inner ring 72 b of the second ball bearing 72, and the inner peripheral surface of the inner ring 72 b is in close contact with the outer peripheral surface of the rotating shaft 21.

  In the yoke housing 40, the rotor 20 is rotatably disposed inside the field magnet 60. The rotor 20 is fixed to the rotation shaft 21, the rotor core 22 that is radially opposed to the field magnet 60, the winding 23 wound around the rotor core 22, and the rectification fixed to the rotation shaft 21. And a child 24.

  The rotary shaft 21 has a base end portion 21a pivotally supported by the first ball bearing 71 on the yoke housing 40 side, and a portion near the tip end portion 21b pivoted on the second ball bearing 72 on the end frame 50 side. Yes. The distal end portion 21b of the rotating shaft 21 protrudes from the bottom portion 51 of the end frame 50, and the output member 101 is fixed to the distal end portion 21b. The output member 101 is connected to a driving target connecting portion (not shown).

  The commutator 24 is fixed to a position on the distal end side (end frame 50 side) of the rotor shaft 22 in the rotating shaft 21, and is disposed on the radially inner side of the side wall portion 52 of the end frame 50. The commutator 24 has a substantially cylindrical shape and includes a plurality of segments 24a made of a conductor on the outer peripheral surface thereof. A winding 23 is connected to each segment 24a.

  The brush device 30 is housed inside the side wall 52 of the end frame 50 in the radial direction. The brush device 30 includes a brush holder 31 fixed to the bottom 51 of the end frame 50 by screws 36 and a power supply brush 32 supported by the brush holder 31.

  The power supply brush 32 is configured to be movable back and forth in the radial direction and is urged radially inward by a coil spring 33 provided on the radially outer side. Thereby, the front-end | tip part of the electric power feeding brush 32 is press-contacted to radial direction with respect to the segment 24a of the commutator 24 arrange | positioned at the inner peripheral side. In addition, a pigtail 34 is connected to the power supply brush 32, and external power supply is made to the power supply brush 32 from the power supply unit 35 provided in the end frame 50 via the pigtail 34. Then, power is supplied from the power supply brush 32 to the segment 24a of the commutator 24 that is in sliding contact.

Next, the operation of this embodiment will be described.
The first ball bearing 71 that pivotally supports the base end portion 21 a of the rotating shaft 21 is accommodated in the bearing accommodating portion 44 of the yoke housing 40. One elastic O-ring 80 is disposed between the first ball bearing 71 and the bearing housing portion 44. As a result, the vibration transmitted from the rotating shaft 21 to the first ball bearing 71 is absorbed by the O-ring 80, so that the vibration transmitted from the rotating shaft 21 to the bearing housing portion 44 is suppressed.

  The bearing housing portion 44 includes a cylindrical holding portion 44b that is in contact with the O-ring 80, and a diameter-expanded portion 44c that is closer to the yoke housing 40 than the holding portion 44b, that is, to the tip portion 21b side of the rotary shaft 21. . The enlarged diameter portion 44c is formed in a tapered shape in which the inner diameter gradually increases from the holding portion 44b toward the distal end portion 21b of the rotating shaft 21. The enlarged diameter portion 44 c suppresses the generation of abnormal noise when the motor 1 is driven. This will be described using a comparative example.

  FIG. 2A and FIG. 2B show a part of the motor of the comparative example. The motor includes a cylindrical bearing housing portion 201, a ball bearing 202 housed in the bearing housing portion 201, and one O-ring 203 disposed between the bearing housing portion 201 and the ball bearing 202. Have. In this motor, the end portion 204a of the rotating shaft 204 swings with the ball bearing on the output end side as a fulcrum. As the rotary shaft 204 swings, the outer ring 202 a of the ball bearing 202 tilts and swings in the direction opposite to the rotary shaft 204. For this reason, the outer ring 202a of the ball bearing 202 comes into contact with the bearing housing portion 201, and noise is generated.

  In contrast to this comparative example, in the bearing housing portion 44 of the present embodiment, the diameter-expanded portion 44c is the rotation shaft 21 with respect to the inner diameter of the holding portion 44b that holds the first ball bearing 71 via one O-ring 80. The inner diameter on the tip end portion 21b side is enlarged. For this reason, even when the outer ring 71a of the first ball bearing 71 is tilted by the swing of the rotating shaft 21 when the motor 1 is driven, contact between the outer ring 71a and the bearing housing portion 44 is prevented. For this reason, generation | occurrence | production of the abnormal noise at the time of the drive of the motor 1 is suppressed.

  The second ball bearing 72 that pivotally supports the vicinity of the tip 21 b of the rotating shaft 21 is directly attached to the bearing housing portion 53 of the end frame 50. For this reason, relative movement of the second ball bearing 72 in the radial direction with respect to the end frame 50 is suppressed, and as a result, vibration in the radial direction of the rotating shaft 21 is easily attenuated. In particular, the distal end portion 21b of the rotating shaft 21 is an end portion on the output side and easily receives external force via the output member 101. Therefore, in the second ball bearing 72 that supports the vicinity of the distal end portion 21b of the rotating shaft 21. By setting it as the support structure which does not use a shock absorbing material as mentioned above, the influence of the external force to the radial direction which the front-end | tip part 21b of the rotating shaft 21 receives can be suppressed effectively. Further, since the O-ring 80 is provided only on the first ball bearing 71 side of the first ball bearing 71 and the second ball bearing 72 that pivotally support the rotating shaft 21, it is possible to contribute to the reduction of the manufacturing cost of the motor 1.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The motor case 10 of the motor 1 has a yoke housing 40 and an end frame 50. The yoke housing 40 has a bearing housing portion 44 that houses the first ball bearing 71, and one O-ring 80 is disposed between the bearing housing portion 44 and the first ball bearing 71. The end frame 50 has a bearing housing portion 53 into which the second ball bearing 72 is fitted. The bearing housing portion 44 includes a cylindrical holding portion 44b that holds the first ball bearing 71 in contact with the O-ring, and a diameter-increased portion that is closer to the bearing housing portion 53 than the holding portion 44b and is larger in diameter than the holding portion 44b. 44c.

  When the motor 1 is driven, the first ball bearing 71 is tilted by the swing of the rotating shaft 21. The diameter-expanded portion 44 c is larger in diameter than the holding portion 44 b that holds the first ball bearing 71 via the O-ring 80. For this reason, the inclined first ball bearing 71 is unlikely to contact the enlarged diameter portion 44 c, that is, the bearing housing portion 44. Therefore, the generation of noise due to the contact between the first ball bearing 71 and the bearing housing portion 44 can be suppressed by the enlarged diameter portion 44c.

  (2) The first ball bearing 71 is disposed between the cylindrical outer ring 71a, the inner ring 71b disposed inside the outer ring 71a, and between the outer ring 71a and the inner ring 71b, and is arranged along the circumferential direction. One row of balls 71c. On the outer peripheral surface of the outer ring 71a, a holding groove 71d in which an O-ring 80 is disposed on the base end 21a side of the rotating shaft 21 from the center of the ball 71c is formed over the entire circumference.

  The outer ring 71a of the first ball bearing 71 is thicker on the end side than the portion located at the center of the ball 71c. Therefore, it is easy to form the holding groove 71d in which the O-ring 80 is disposed at a position shifted from the center of the ball 71c.

  (3) The rotor core 22 around which the winding 23 is wound and the commutator 24 connected to the winding 23 are disposed at a portion between the first ball bearing 71 and the second ball bearing 72 in the rotating shaft 21. Is provided. The commutator 24 is provided between the rotor core 22 and the second ball bearing 72.

  The second ball bearing 72 fitted in the bearing housing portion 53 is less likely to vibrate than the first ball bearing 71. Since the commutator 24 is provided between the rotor core 22 and the second ball bearing 72, the commutator 24 can be disposed closer to the second ball bearing 72, so that vibration of the commutator 24 can be suppressed. As a result, the slidable contact state between the commutator 24 and the power supply brush 32 is stabilized, which can contribute to the performance improvement of the motor 1.

In addition, you may implement each said embodiment in the following aspects.
-Although the bearing accommodating part of the said embodiment has the enlarged diameter part 44c formed in the taper shape from which an internal diameter becomes large gradually, you may change the shape of the enlarged diameter part 44c suitably.

  As shown in FIG. 3A, the bearing housing portion 111 includes a holding portion 111a and a diameter-expanded portion 111b. The enlarged diameter portion 111b has an enlarged inner diameter with a cross section along the central axis of the rotating shaft 21 having an arc shape (R shape).

  As shown in FIG. 3B, the bearing housing portion 112 includes a holding portion 112a and an enlarged diameter portion 112b. The enlarged diameter portion 112b is formed in a cylindrical shape having an inner diameter larger than the inner diameter of the holding portion 112a. In the bearing housing portion 112, the cross section along the central axis of the rotating shaft 21 has a stepped shape along the central axis.

  In the above embodiment, the holding groove 71d in which the O-ring 80 is disposed is formed in the outer ring 71a of the first ball bearing 71. However, even if the holding groove is formed on the inner peripheral surface of the holding portion 44b of the bearing housing portion 44, Good.

In contrast to the above embodiment, the O-ring 80 only needs to be formed of a material having elasticity, such as a rubber material, an elastomer, and other resin materials.
In the above embodiment, the motor 1 has a configuration of 4 poles and 22 slots, but the number of poles on the yoke housing 40 side (field side) and the number of slots on the rotor 20 side (number of teeth around which the winding 23 is wound) ) Can be appropriately changed according to the configuration. Moreover, in the said embodiment, it is good also as an aspect which has a some winding layer for the winding aspect of the coil | winding 23 with respect to the rotor core 22. FIG.

-Although the motor of the said embodiment is a DC motor, it is not restricted to this, It is good also as motors other than a DC motor.
As shown in FIG. 4, the motor 120 is a brushless motor. The motor case 121 of the motor 120 has a case main body 130 and an end frame 140.

  The case body 130 has a circular bottom 131 and a cylindrical side wall 132 extending in the axial direction (leftward in FIG. 4) from the outer periphery of the bottom 131, and is opposite to the bottom 131 in the axial direction. It has a bottomed cylindrical shape having an opening 133 at the end. The end frame 140 is assembled to the case body 130 so as to substantially close the opening of the case body 130.

  A stator 170 having a cylindrical shape and wound with a winding 171 is fixed to the inner peripheral surface of the side wall portion 132, and the rotor 180 is disposed inside the stator 170. The rotor 180 includes a rotating shaft 181, a rotor core 182 fixed to the rotating shaft 181, and a magnet 183 fixed to the rotor core 182.

A bearing housing portion 134 that protrudes to the outside in the axial direction (the right side in FIG. 4) is formed at the central portion in the radial direction of the bottom 131 of the case body 130.
Similarly to the above-described embodiment, the bearing housing portion 134 includes a circular housing bottom portion 134a, a cylindrical holding portion 134b extending from the outer peripheral edge of the housing bottom portion 134a toward the bottom portion 131, and the holding portion 134b and the bottom portion 131. And an enlarged diameter portion 134c formed therebetween. The enlarged diameter portion 134c is formed in a tapered shape whose inner diameter gradually increases from the holding portion 134b toward the bottom portion 131.

  A first ball bearing 151 is accommodated in the bearing accommodating portion 134. One O-ring 160 is disposed between the first ball bearing 151 and the bearing housing part 134 (holding part 134b). The O-ring 160 is disposed closer to the base end portion 181a of the rotation shaft 181 than the center of the ball 151c included in the first ball bearing 151. The O-ring 160 is disposed in a holding groove 151 d formed over the entire outer peripheral surface of the first ball bearing 151.

  A bearing housing portion 141 is formed at the center of the end frame 140, and a second ball bearing 152 that rotatably supports the rotating shaft 181 is fitted into the bearing housing portion 141 (may be a clearance fit or a tight fit). Has been. The outer peripheral surface of the second ball bearing 152 is in close contact with the inner peripheral surface of the bearing accommodating portion 141.

  In such a motor 120 as well, the contact between the first ball bearing 151 and the case main body 130 can be prevented and the generation of abnormal noise can be suppressed, as in the above embodiment. Arranging one O-ring 160 between the first ball bearing 151 and the bearing housing portion 134 contributes to a reduction in the manufacturing cost of the motor 120.

  -You may combine embodiment mentioned above and each modification suitably.

DESCRIPTION OF SYMBOLS 1 ... Motor, 10 ... Motor case, 20 ... Rotor, 21 ... Rotary shaft, 22 ... Rotor core, 23 ... Winding, 24 ... Commutator, 44b ... Holding part, 44c ... Expanding part, 71 ... 1st ball bearing, 71a ... Outer ring, 71b ... Inner ring, 71c ... Ball, 71d ... Holding groove, 72 ... Second ball bearing, 80 ... O-ring.

Claims (3)

A motor case having a first bearing housing portion and a second bearing housing portion;
A rotor having an output end for outputting rotation to one end in the axial direction, and a rotor disposed inside the motor case;
A first ball bearing housed in the first bearing housing portion and rotatably supporting the rotary shaft;
A second ball bearing that is fitted in the second bearing housing and rotatably supports the rotating shaft;
One O-ring having elasticity and in contact with both the first ball bearing and the first bearing housing;
Have
The first bearing housing portion includes a cylindrical holding portion that is in contact with the O-ring to hold the first ball bearing, and is closer to the second bearing housing portion than the holding portion and from the holding portion. A motor characterized by including an enlarged diameter portion. The motor according to claim 1,
The first ball bearing is
A cylindrical outer ring,
An inner ring disposed inside the outer ring and fitted with the rotating shaft;
A row of balls disposed between the outer ring and the inner ring and arranged along a circumferential direction;
Including
The motor is characterized in that a holding groove in which the O-ring is disposed on the outer peripheral surface of the outer ring on the end side of the rotating shaft from the center of the ball over the entire circumference. The motor according to claim 1 or 2,
A portion of the rotating shaft between the first ball bearing and the second ball bearing is provided with a rotor core around which a winding is wound, and a commutator connected to the winding.
The commutator is provided between the rotor core and the second ball bearing.

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