JP2016178815A - Bearing structure for motor, and bearing mounting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing structure for a motor capable of stabilizing rotations of a rotary shaft and reducing vibrations or noise by assembling the rotary shaft and a bearing member that receives the shaft center, while matching the shaft centers thereof.SOLUTION: The bearing structure for the motor comprises: an annular bearing member 22 that supports a shaft 3; and a holder part 25 including a recess 33 in which the bearing member 22 is held, and a shaft hole 29 through which a distal end of the shaft 3 is passed, on a bottom of the recess 33. In an outer peripheral part of the bearing member 22, an alignment member 24 is provided which positions the bearing member 22 relatively to the holder part 25. The recess 33 of the holder part 25 is formed conical towards the bottom, and an outer peripheral surface of the alignment member 24 is formed in a curved surface in a direction of a shaft center C of the shaft 3. The outer peripheral surface of the alignment member 24 is abutted to an inner peripheral surface 34 of the recess 33, and the bearing member 22 is positioned in the holder part 25.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a motor bearing structure and a bearing mounting method for incorporating into a housing in a state where the axis of a rotating shaft and the axis of a bearing member that holds the rotating shaft are aligned.

  A conventional general motor has a cylindrical housing with one open end, a bracket that closes the open end of the housing, a rotating shaft (shaft) that is rotatably arranged in the housing, and a coil wound around And a rotor having a core, a commutator, and the like, and a stator having a magnet and the like that are arranged so as to surround the core and generate magnetic flux necessary for rotation of the shaft (Patent Document 1). .

  A configuration example of the bearing portion in the motor is shown in FIG. As shown in FIG. 7A, the shaft 3 is provided with a bearing member 22 that keeps rotating along the outer peripheral surface of the shaft 22, and the holder member 55 is provided on the bracket 51 side. By being fitted in the recess 53, the tip of the shaft 3 is rotatably held in a state of being exposed from the shaft hole 29 provided on the bracket 51 side. Then, as shown in FIG. 7B, the bearing member 22 is fixed to the concave portion 53 by press-fitting or bonding in a state of being integrated with the shaft 3.

JP 2000-156952 A

  In the bearing structure as shown in FIG. 7, the shaft 3 and the bearing are caused by poor fitting or mounting error between the bearing member 22 that holds the rotation of the shaft 3 and the holder portion 55 that receives the bearing member 22. There was a case where a deviation occurred in the axis C of the member 22. As a result, there is a problem that uneven rotation occurs in the shaft 3 and vibration and noise are generated accordingly.

  Further, when the bearing member 22 is fitted into the concave portion 53 of the holder portion 55 by press-fitting, an unreasonable force is applied between the shaft 3 and the bearing member 22 due to the press-fitting direction and the force applied at the time of press-fitting, Both axial centers C may be displaced, and it has been difficult to match the axial centers C of the shaft 3 and the bearing member 22.

  In order to prevent such a shift of the axis C, it is necessary to use parts with small tolerances for the shaft 3 and the bearing member 22 and to perform assembly and adjustment with high accuracy. As a result, there is a problem that the cost and man-hours for producing the motor increase and mass production becomes difficult.

  Therefore, the present invention can stabilize the rotation of the rotation shaft and reduce vibration and noise by assembling the rotation shaft and the shaft center of the bearing member that receives the rotation shaft in alignment. An object of the present invention is to provide a motor bearing structure and a bearing mounting method.

  In order to solve the above-mentioned problems, a motor bearing structure according to the present invention includes a rotating shaft, an annular bearing member that supports the rotating shaft, a recess in which the bearing member is held, and the rotating shaft at the bottom of the recess. And a holding member having a shaft hole through which the tip of the bearing member is provided, an alignment member for positioning the bearing member with respect to the holding member is provided on an outer peripheral portion of the bearing member, A concave portion is formed in a conical shape toward the bottom, and an outer peripheral surface of the aligning member is formed in a curved shape along the axial direction of the rotating shaft, and the outer peripheral surface of the aligning member is an inner peripheral surface of the concave portion. The bearing member is positioned on the holding member by contact.

  Further, the motor bearing mounting method of the present invention is a motor bearing mounting method in which an annular bearing member that supports a rotating shaft of a rotor is fitted into a recess of a holding member that holds the bearing member. An aligning member for positioning the bearing member with respect to the holding member is provided on the outer peripheral portion, and the outer peripheral surface of the aligning member is formed in a curved shape along the axial direction of the rotating shaft, and is conical toward the bottom portion. When the aligning member is fitted into the concave portion of the holding member formed in, the bearing member is positioned such that the outer peripheral surface of the aligning member follows the inner peripheral surface of the concave portion of the holding member. .

  According to the motor bearing structure of the present invention, the concave portion of the holding member is formed in a conical shape toward the bottom, and the outer peripheral surface of the aligning member is formed in a curved shape along the axial direction of the rotation shaft. The shaft center and the shaft center of the bearing member can be assembled to the holding member while being positioned in a substantially aligned state. As a result, the shaft can be rotated more smoothly, and vibration and noise associated with the rotation can be effectively reduced.

  Further, according to the motor bearing mounting method of the present invention, the bearing member is positioned so that the outer peripheral surface of the aligning member follows the inner peripheral surface of the holding member. No adjustment is required.

It is sectional drawing of the motor which concerns on this invention. It is an assembly perspective view of the motor. It is a perspective view of the holding member of the said motor. It is sectional drawing which shows the bearing structure of the said motor. It is a perspective view of the aligning member of the said motor. It is sectional drawing which shows the effect | action of the bearing structure of the said motor. It is sectional drawing which shows the bearing structure of the conventional motor.

  Hereinafter, an embodiment in which a motor bearing structure of the present invention is applied to a brush motor will be described with reference to the drawings. As shown in FIGS. 1 and 2, the motor 1 of this embodiment includes a rotor 11 and a stator 12. The rotor 11 is provided with a rotating shaft (shaft) 3 for transmitting rotational force to the outside, a pair of annular bearing members 22 that support the rotation of the shaft 3, and a central portion in the longitudinal direction of the shaft 3. And an iron core (core) 4 serving as a magnetic flux passage. A commutator 9 and a brush 5 for switching the direction and phase of the current flowing through the coil 17 are disposed on the shaft 3, and a plurality of grooves (core slots) are formed on the core 4. A winding (coil) 17 is wound around the core slot many times. For this reason, the coil 17 is disposed on both sides of the core 4 so as to swell. An insulating layer 16 that keeps the insulation between the core 4 and the coil 17 is interposed. The insulating layer 16 is made of, for example, epoxy resin.

  The stator 12 includes a housing 2 that houses the rotor 11, and a plurality of magnets 15 that are fixed at equal intervals along the inner peripheral surface of the housing 2. The plurality of magnets 15 generate magnetic flux necessary for generating torque of the rotor 11.

  The housing 2 is formed into a cylindrical shape by subjecting a steel plate to a deep drawing process, and the rotor 11 is assembled and fixed to the housing 2 with a pair of opposed open ends projecting the tip of the shaft 3. A disc-shaped bracket 21 is attached for the purpose. The shaft 3 is rotatably supported through a shaft hole 29 provided in the central portion of the bracket 21. The bracket 21 is made of the same steel plate as the housing 2.

  As shown in FIG. 3, the bracket 21 is provided with a holder portion 25 for contacting and holding the outer peripheral surface and the bottom portion of the bearing member 22. The holder portion 25 has a recess 33 in which a central portion of the bracket 21 is recessed in a conical shape, and the shaft hole 29 is provided at the bottom of the recess 33.

  As shown in FIG. 2, the bracket 21 is fitted so as to close the open end of the housing 2, thereby positioning the shaft 3 attached to the bearing member 22. As shown in FIG. 4, the shaft 3 is held in a state having a predetermined spatial distance t so as not to contact a shaft hole 29 provided in the holder portion 25.

  Next, the bearing structure of the shaft 3 in the motor 1 will be described with reference to FIG. The bearing structure of the present embodiment includes a shaft 3, annular bearing members 22 attached to both ends of the shaft 3, an alignment member 24 provided on the outer peripheral portion of the bearing member 22, and the alignment member 24. It is comprised by the holder part 25 to hold | maintain. An elastic washer member (washer spring) 26 is disposed between the bearing member 22 and the alignment member 24. The washer spring 26 is provided to determine the position of the inner ring 18b in the axial direction by applying a preload to the outer ring 18a of the bearing member 22.

  The bearing member 22 is formed of a rolling bearing made of a conductive material having a plurality of rolling elements that roll while moving in contact with the rotation surface of the shaft 3. This rolling bearing is composed of an outer ring 18a, an inner ring 18b, a rolling element 19 and a cage 20 that holds them, and the inner ring 18b is fixed to the shaft 3 by press-fitting or using an adhesive.

  The alignment member 24 covers an annular portion 31 that holds the outer peripheral portion 23 of the bearing member 22 and a surface that is orthogonal to the direction of the shaft 3 (axial center C) inserted through the bearing member 22. The bottom portion 32 is formed of an insulating material, and a through hole 28 for inserting one end of the shaft 3 is provided at the center of the bottom portion 32. The alignment member 24 can reduce the occurrence of electric discharge with the bearing member 22 by using a heat-resistant resin having a high insulating property, thereby obtaining the effect of preventing electrolytic corrosion.

  As shown in FIG. 4, the outer peripheral surface 31 a of the annular portion 31 of the aligning member 24 has an arcuate curved shape along the axis C direction of the shaft 3, and an intermediate portion of this curved shape It is formed so that the wall thickness T is the maximum thickness. Further, as shown in FIG. 5, the outer peripheral surface 31a is formed with a plurality of grooves 36 along its curved surface. By providing the groove 36 uniformly with respect to the circumferential direction of the outer peripheral surface 31a, an elastic force is generated on the outer peripheral surface 31a, and the holder portion 25 can be fitted with buffering properties.

  The aligning member 24 has a washer spring 26 mounted on the bottom portion 32, and the bearing member 22 is mounted integrally with the shaft 3 along the inner peripheral surface of the annular portion 31.

  The concave portion 33 of the holder portion 25 into which the aligning member 24 is fitted has a conical inner peripheral surface 34 with a predetermined depth and a circular bottom surface 35. The inner peripheral surface 34 is formed in a taper shape so that the inner diameter gradually decreases from the opening side toward the bottom surface 35. The inner peripheral surface 34 is formed such that the opening diameter Φ2 is larger than the outer peripheral diameter Φ1 including the thickness T of the aligning member 24, and the inner diameter Φ3 of the bottom surface 35 is smaller than the Φ1.

  For this reason, when the alignment member 24 is fitted into the recess 33, it can be easily inserted while being displaced without resistance in the direction along the axis C of the shaft 3 on the opening side of the recess 33. It can be gradually press-fitted and fixed while maintaining the posture along the axis C of the shaft 3 as it goes toward the bottom surface 35 of the recess 33. Further, since the shaft member 22 is attached to the aligning member 24 via a washer spring 26, when the shaft member 22 is press-fitted into the concave portion 33 of the holder portion 25, an impact applied to the shaft 3 can be absorbed. Thereby, the shift of the axis C of the shaft 3 can be prevented.

  Next, a bearing mounting method will be described. As shown in FIG. 2, the bearing member 22, the washer spring 26, and the alignment member 24 are attached to the shaft 3, and after these are integrated, the alignment member 24 is fitted into the recess 33 of the holder portion 25. . This fitting is performed by fixing the bracket 21 having the holder portion 25 to the housing 2.

  As shown in FIG. 6A, when the bearing member 22 and the alignment member 24 with which the shaft 3 is integrated are fitted into the recess 33 of the holder portion 25, as shown in FIG. The position where the aligning member 24 abuts on the recess 33 is displaced without resistance in accordance with the fitting direction and fitting force. In this way, by causing the outer peripheral surface of the aligning member 24 to follow the inner peripheral surface 34 of the concave portion 33, as shown in FIG. 6C, the shaft center C of the shaft 3 and the shaft of the bearing member 22. The center C is positioned in the recess 33 in a posture that automatically matches. Then, by fixing the bracket 21 to the housing 2 with a fixing tool such as a screw, the bearing member 22 integrated with the alignment member 24 is fixed to the holder portion 25.

  In the conventional bearing structure shown in FIG. 7, the shaft center of the shaft 3 and the bearing member 22 is inserted into the shaft hole 29 by directly incorporating the bearing member 22 to which the shaft 3 is attached into the recess 53 of the holder portion 55. Although it was tried to match C, in such a structure, all the shaft centers must be matched, and for this reason, a slight shift may occur in the shaft center C between the shaft 3 and the bearing member 22. It was. On the other hand, in the present invention, the bearing member 22 to which the shaft 3 is mounted is held by the aligning member 24, and the aligning member 24 is combined with the holder 25 in a state having a certain amount of play. An unreasonable force is applied between the bearing member 22 and the bearing member 22, and the misalignment between the shaft centers C is less likely to occur.

  As described above, when the motor is assembled, even if the axis C of the shaft 3 and the axis C of the shaft hole 29 of the bracket 21 do not completely coincide with each other, the axes of both the shaft 3 and the bearing member 22 are obtained. Since the structure is such that C automatically coincides, the rotation of the shaft 3 becomes smooth, and vibration and noise can be greatly reduced.

  Next, based on FIG. 4, the relationship between the thickness T of the annular portion 31 of the aligning member 24 and the distance between the bearing member 22 and the holder portion 25 will be described. When the motor 1 is driven by inverter control, high-frequency voltage, static electricity, or the like is generated and flows through a path with low resistance. Therefore, in the aligning member 24 formed of an insulating material, a voltage exceeding the volume resistivity of the material is applied, so that an excessive current flows and the function as the insulating member may not be performed. .

  Therefore, the wall thickness T of the annular portion 31 of the aligning member 24 corresponding to the creeping distance at which both the conductive bearing member 22 and the holder portion 25 are connected via the insulating aligning member 24 is set to the holder portion 25. By setting the shaft hole 29 larger than the spatial distance t between the shaft 3 and the shaft hole 29 provided, it is possible to discharge a high-frequency current and static electricity generated by driving by inverter control during the spatial distance t. Therefore, by setting the maximum thickness of the annular portion 31 of the aligning member 24 to be the creepage distance t or more, even if a high voltage is applied between the shaft 3 and the bearing member 22, the insulation of the aligning member 24 is achieved. There is no such thing as deterioration or destruction. Thereby, the electrolytic corrosion of the bearing member 22 that inhibits the rotation of the shaft 3 can be effectively prevented.

C axis 1 motor 2 housing 3 shaft (rotating shaft)
4 core 5 brush 9 commutator 11 rotor 12 stator 15 magnet 16 insulating layer 17 coil 18a outer ring 18b inner ring 19 rolling element 20 cage 21 bracket 22 bearing member 23 outer peripheral portion 24 alignment member 25 holder portion (holding member)
26 Washer spring 28 Through hole 29 Shaft hole 31 Ring portion 31a Outer peripheral surface 32 Bottom 33 Recessed portion 34 Inner peripheral surface 35 Bottom surface 36 Groove portion 51 Bracket 53 Recessed portion 55 Holder portion

Claims (9)

A motor bearing comprising a rotary shaft, an annular bearing member that supports the rotary shaft, a concave portion that holds the bearing member, and a holding member that has a shaft hole through which the tip of the rotary shaft passes through the bottom of the concave portion. In structure
An alignment member for positioning the bearing member with respect to the holding member is provided on an outer peripheral portion of the bearing member,
Forming the concave portion of the holding member in a conical shape toward the bottom and forming the outer peripheral surface of the aligning member in a curved shape along the axial direction of the rotating shaft;
A motor bearing structure, wherein an outer peripheral surface of the alignment member is brought into contact with an inner peripheral surface of the recess to position the bearing member on the holding member.   The motor bearing structure according to claim 1, wherein a plurality of grooves along the axial direction of the rotation shaft are formed on an outer peripheral surface of the alignment member.   The motor bearing structure according to claim 1, wherein an outer peripheral surface of the aligning member has an arcuate curved shape.   The motor bearing structure according to claim 1, wherein the bearing member is a rolling bearing made of a conductive material, and the alignment member is made of an insulating material.   When the aligning member is provided integrally with the bearing member that supports the rotating shaft, and the aligning member is fitted to the holding member, the outer peripheral surface of the aligning member is the inner peripheral surface of the recess of the holding member. The motor bearing structure according to claim 1, wherein the shaft center of the rotating shaft and the shaft center of the bearing member coincide with each other.   The alignment member includes an annular portion that holds an outer peripheral portion of the bearing member, and a bottom portion that covers one surface orthogonal to the axial direction of the rotation shaft of the bearing member, and includes one surface of the bearing member and the alignment member. The motor bearing structure according to claim 1, wherein an elastic washer member is disposed between the bottom portion and the bottom portion.   2. The motor bearing structure according to claim 1, wherein the alignment member has a creeping distance in contact with the bearing member and the holding member that is greater than a spatial distance between the shaft hole and the rotation shaft. In the motor bearing mounting method of fitting the annular bearing member supporting the rotating shaft of the rotor into the recess of the holding member that holds the bearing member,
Providing an aligning member for positioning the bearing member with respect to the holding member at an outer peripheral portion of the bearing member, and forming an outer peripheral surface of the aligning member into a curved shape along the axial direction of the rotation shaft;
When the aligning member is fitted into the concavity of the holding member formed in a conical shape toward the bottom, the outer peripheral surface of the aligning member follows the inner peripheral surface of the concavity of the holding member to position the bearing member. A bearing mounting method for a motor.   A centering member is attached to and integrated with the bearing member that supports the rotating shaft, and the aligning member is fitted into the recess of the holding member in a state where the shaft center of the rotating shaft and the shaft center of the bearing member coincide with each other. The motor bearing mounting method according to claim 8.

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