JP2012235665A - Assembly method of outer rotor type brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an assembly method of an outer rotor type brushless motor which enables a thrust pad to be assembled to a stator without applying an excess load to a motor body and improves the assemblability while maintaining the small size of the motor.SOLUTION: When a thrust pad 8 is press-fitted to or crimped and assembled to a stepped part 2d provided at a peripheral part of a shaft hole 2a of a housing 2 after a stator 1 is assembled to a rotor 10, a load acting on a motor is received by a cylindrical housing end surface 2e through a through hole 11b of a rotor yoke 11.

Description

  The present invention relates to a method for assembling an outer rotor type brushless motor used in, for example, OA equipment, home appliances, industrial equipment and the like.

For example, an outer rotor type DC brushless motor will be described with reference to FIGS.
The structure of the stator 50 will be described. A cylindrical metal oil-impregnated bearing 52 made of sintered metal is coaxially assembled in a shaft hole 51a of the housing 51 formed in a cylindrical shape. A stator core 53 in which a coil 54 is wound around pole teeth 53 a radially projecting toward the outer peripheral side is assembled to the outer periphery on one end side of the housing 51. Further, a motor board 55 is press-fitted or caulked to the outer periphery of the other end side of the housing 51 and assembled. The motor substrate 55 is provided with a sensor substrate (not shown) on which a Hall element is mounted.

  Next, the structure of the rotor 56 will be described. On one side of the rotor shaft 57, a rotor yoke 58 formed in a cup shape is integrally assembled by press-fitting or shrink fitting. A ring-shaped rotor magnet 59 is assembled on the inner peripheral surface of the rotor yoke 58. A circumferential groove 57a is formed on the other side of the rotor shaft 57, and a ring-shaped retaining washer 60 is fitted into the circumferential groove 57a.

After assembling the stator 50, the rotor shaft 57 is inserted into the rotor 56 through the metal oil-impregnated bearing 52. At this time, the pole teeth 53a of the stator core 53 and the rotor magnet 59 are assembled so as to face each other.
Then, a retaining washer 60 is fitted into the circumferential groove 57 a of the rotor shaft 57, so that the rotor 56 is secured against the stator 50.

Further, it is necessary to close the shaft hole 51 a of the housing 51 with the thrust receiver 61 so that the lubricating oil impregnated in the metal oil-impregnated bearing 52 does not leak from the shaft end. Specifically, the thrust receiver 61 is assembled to the stepped portion 51 b provided at the peripheral edge of the shaft hole of the housing 51 so as to overlap the resin sheet 62.
As a method of assembling the thrust receiver 61, a method of press-fitting or caulking (see FIGS. 2A and 2B) and a method of screwing the housing 51 using a set screw 63 (see FIGS. 3A and 3B). ) Has been employed (see Patent Document 1).

Japanese Patent Laid-Open No. 10-174352

  However, in the assembling method by press-fitting or caulking shown in FIGS. 2A and 2B, there is only a method for receiving the load received by the motor side when the thrust receiver 61 is press-fitted or caulking by the motor substrate 55. In this case, the motor substrate There is a possibility that 55 is distorted or plastically deformed.

  In addition, when screwing to the housing 51 using the set screw 63 shown in FIGS. 3A and 3B, it is necessary to provide a screw hole 51b on the housing 51 side. There is a problem that the motor becomes thicker in the direction and the motor becomes larger.

  The present invention has been made to solve these problems, and an object of the present invention is to allow a thrust receiver to be assembled to the stator without applying an excessive load to the motor body, and to keep the motor downsized. Another object of the present invention is to provide a method for assembling an outer rotor type brushless motor with improved assemblability.

In order to achieve the above object, the present invention comprises the following arrangement.
Assembling a stator by assembling a cylindrical metal oil-impregnated bearing concentrically with a shaft hole of a housing formed in a cylindrical shape, and assembling a stator core and a motor substrate each having a coil wound around poles on the outer periphery of the housing; The rotor shaft is assembled with a cup-shaped rotor yoke, and a rotor provided with a magnet on the inner periphery of the rotor yoke is inserted into the metal oil-impregnated bearing, and the rotor shaft is provided in the vicinity of the shaft end of the rotor shaft. A step of assembling a retaining member in the groove to prevent the retaining member from being assembled to the stator, and a jig passing through the through hole through the through hole provided at a position facing the housing end surface of the rotor yoke is pressed against the housing end surface. The thrust receiver is press-fitted into the stepped portion provided at the peripheral edge of the shaft hole of the housing in a state where the motor load is received at And having a step Shimete closing, the.

  By using the outer rotor type brushless motor assembly method described above, the rotor yoke is penetrated when the thrust receiver is press-fitted into the stepped portion provided at the peripheral edge of the shaft hole of the housing and then closed by closing the thrust receiver after the rotor is assembled to the stator. By pressing the jig that passes through the hole against the end face of the cylindrical housing, the end face of the housing receives the load acting on the motor, so there is no need for the motor parts to be deformed or thick, and the motor size is maintained. Assemblability can be improved while maintaining this.

In the present invention, it is preferable that a plurality of through holes facing the housing end surface of the rotor yoke are provided, and more preferably, three or more through holes are provided at equal intervals in the circumferential direction.
According to this, the jig is pressed against the cylindrical housing end surface through the plurality of through holes of the rotor yoke, and the housing end surface is supported at a plurality of locations to support the motor in a stable state, and the thrust receiver is supported by the shaft hole of the housing. It can be closed by press-fitting or crimping.

In the present invention, the thrust receiver is preferably assembled by overlapping resin sheets.
Thereby, wear due to the difference in hardness between the rotor shaft and the thrust receiver can be prevented.

In the present invention, it is preferable that the through hole provided in the rotor yoke is closed with a sealing material after the thrust receiver is assembled to the housing.
Thereby, it is possible to prevent the lubricating oil impregnated in the metal oil-impregnated bearing through the through-hole of the rotor yoke from leaking without using special parts.

  By using the outer rotor type brushless motor assembling method described above, the thrust receiver can be assembled to the stator without excessive load acting on the motor body, and the assemblability can be improved while maintaining the miniaturization of the motor. it can.

It is a section explanatory view, a partial enlarged view, and a bottom view of an outer rotor type DC brushless motor. It is sectional explanatory drawing and the bottom view of the conventional outer rotor type | mold DC brushless motor. It is sectional explanatory drawing and the bottom view of the conventional outer rotor type | mold DC brushless motor.

  Embodiments of an outer rotor type brushless motor assembling method according to the present invention will be described below with reference to the accompanying drawings. In this embodiment, an outer rotor type DC brushless motor will be described.

  With reference to Fig.1 (a), schematic structure of an outer rotor type | mold DC brushless motor is demonstrated. The structure of the stator 1 will be described. A cylindrical metal oil-impregnated bearing 3 (outer diameter of about 4 mm) made of sintered metal is assembled coaxially in the shaft hole 2a of the housing 2 formed in a cylindrical shape. A small-diameter stepped portion 2b is formed on the outer periphery of one end of the housing 2, and the stator core 4 is fitted and fixed to the stepped portion 2b. The stator core 4 is a laminated core, and a motor coil 5 is wound around pole teeth 4a that project radially toward the outer peripheral side.

A large-diameter stepped portion 2c is formed on the outer periphery of the other end of the housing 2, and the motor board 6 is press-fitted or crimped into the stepped portion 2c. The motor substrate 6 is provided with a sensor substrate (not shown) on which Hall elements are mounted.
Furthermore, a stepped portion (dual step) 2d is formed at the peripheral edge of the other end of the shaft hole 2a of the housing 2, and a resin sheet 7 (PEEK material) is fitted into the stepped portion 2d. The thrust receiver 8 is press-fitted or caulked and assembled on the resin sheet 7 (see FIG. 1C). The resin sheet 7 is provided to prevent wear due to a difference in hardness between a rotor shaft 9 (made of iron) and a thrust receiver 8 (made of brass), which will be described later. The thrust receiver 8 receives the thrust load of the rotor 10 and is a metal oil-impregnated bearing. 3 is provided so that the lubricating oil impregnated in 3 does not leak out.

  Next, the structure of the rotor 10 will be described. On one side of the rotor shaft 9 (with an outer diameter of about 2 mm), a rotor yoke 11 formed in a cup shape is integrally assembled into a fitting hole 11a provided in the center by press fitting or shrink fitting. The rotor yoke 11 is made of a magnetic material. A ring-shaped rotor magnet 12 is assembled on the inner peripheral surface of the rotor yoke 11. The rotor magnet 12 has N poles and S poles alternately formed in the circumferential direction, and the axial length is larger than the axial length of the pole teeth 4 a of the stator core 4.

A plurality of (preferably three or more circumferentially spaced) through holes 11b are formed around the fitting hole 11a of the rotor yoke 11 and facing the housing end surface 2e of the housing 2. (Refer to FIG. 1 (b) enlarged view).
A circumferential groove 9a is formed on the other side of the rotor shaft 9, and a ring-shaped retaining washer 13 is fitted into the circumferential groove 9a. Since the outer diameter of the retaining washer 13 is larger than that of the rotor shaft 9 and smaller than the inner diameter of the shaft hole 2a, the retaining washer 13 abuts against the end face of the metal oil-impregnated bearing 3 even if the rotor shaft 9 tries to move in the axial direction. 2 is secured to the stator 1.

Next, a method for assembling the outer rotor type DC brushless motor configured as described above will be described.
In FIG. 1A, a cylindrical metal oil-impregnated bearing 3 is assembled concentrically into a shaft hole 2a of a housing 2 formed in a cylindrical shape, and a stator core 4 and a motor substrate 6 are assembled to the outer periphery of the housing 2, respectively. Assemble 1

Further, a cup-shaped rotor yoke 11 is assembled to the rotor shaft 9, and the rotor 10 having the rotor magnet 12 provided on the inner periphery of the rotor yoke 11 is assembled.
Then, the rotor shaft 9 is inserted into the shaft hole 3 a of the metal oil-impregnated bearing 3 and the retaining washer 13 is assembled to the circumferential groove 9 a provided in the vicinity of the shaft end of the rotor shaft 9, so that the rotor 10 is attached to the stator 1. Assemble and assemble.

Next, a step provided on the peripheral edge of the shaft hole 2a of the housing 2 in a state where a motor load is received at a plurality of positions by a jig (not shown) through a through hole 11b provided at a position facing the housing end surface 2e of the rotor yoke 11. The resin sheet 7 is placed on the portion 2d, and the thrust receiver 8 is press-fitted or crimped to close.
As a result, the shaft end of the rotor shaft 9 comes into contact with the resin sheet 7 and receives the thrust load of the rotor 10 by the thrust receiver 8. At this time, the rotor magnet 12 is assembled such that the axial center of the rotor magnet 12 is shifted upward from the axial center of the pole teeth 4 a of the stator yoke 4. As a result, the rotor magnet 12 is attracted to the magnetic flux acting surface of the pole teeth 4 a and assembled so that the downward component force acts on the rotor 10.

  If the outer rotor type brushless motor assembling method is used, after the rotor 10 is assembled to the stator 1, the thrust receiver 8 is press-fitted into the stepped portion 2d provided on the peripheral edge of the shaft hole 2a of the housing 2 and closed. At this time, since the load acting on the motor is received at the cylindrical housing end surface 2e through the through hole 11b of the rotor yoke 11, there is no need to deform the motor part or to make the motor part thick, and the motor size is reduced. Assembling property can be improved while maintaining the above.

Further, after the thrust receiver 8 is assembled to the housing 2, it is preferable to close the through hole 11 b provided in the rotor yoke 11 with a sealing material (for example, a nameplate seal).
Thereby, it is possible to prevent the lubricating oil impregnated in the metal oil-impregnated bearing 3 from leaking through the through hole 11b of the rotor yoke 11 without using any special parts.

  In the above embodiment, the outer rotor type brushless motor is used as a driving source for a wide range of equipment such as OA equipment, home appliances, and industrial equipment.

DESCRIPTION OF SYMBOLS 1 Stator 2 Housing 2a, 3a Shaft hole 2b, 2c, 2d Stepped part 2e Housing end surface 3 Metal oil-impregnated bearing 4 Stator core 4a Polar tooth 5 Motor coil 6 Motor board 7 Resin sheet 8 Thrust receiver 9 Rotor shaft 9a Circumferential groove 10 Rotor 11 Rotor yoke 11a Fitting hole 11b Through hole 12 Rotor magnet 13 Retaining washer

Claims (4)

Assembling a stator by assembling a cylindrical metal oil-impregnated bearing concentrically with a shaft hole of a housing formed in a cylindrical shape, and assembling a stator core and a motor substrate each having a coil wound around poles on the outer periphery of the housing; ,
A rotor with a cup-shaped rotor yoke assembled to the rotor shaft and a magnet provided on the inner periphery of the rotor yoke. The rotor shaft is inserted into the metal oil-impregnated bearing, and a circumferential groove provided near the shaft end of the rotor shaft. Attaching the retaining member to the stator and attaching the retaining member to the stator;
Provided at the peripheral edge of the shaft hole of the housing in a state where a motor load is received by pressing a jig passing through the through hole through a through hole provided at a position facing the housing end surface of the rotor yoke. And a step of press-fitting or crimping a thrust receiver on the stepped portion to close the outer rotor type brushless motor.   2. The outer rotor type brushless motor assembling method according to claim 1, wherein a plurality of through holes facing the housing end surface of the rotor yoke are provided.   The outer rotor type brushless motor assembling method according to claim 1, wherein the thrust receiver is assembled by overlapping resin sheets.   3. The outer rotor brushless motor assembling method according to claim 1, wherein after the thrust receiver is assembled to the housing, a through hole provided in the rotor yoke is closed with a sealing material.

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