JP4395141B2 - Motor housing fixing structure - Google Patents

Description

  The present invention relates to an improvement in a motor housing fixing structure in which a plate-like cover is fixed to one end of a hollow metal housing in which a through-hole through which a rotor shaft passes is formed at the center.

Outer rotor type DC brushless motors are often used as motors for centrifugal fans and axial fans.
FIG. 4 is a cross-sectional view showing a conventional DC brushless motor 1 of this type. The conventional DC brushless motor 1 is configured by arranging a stator 20 and a rotor 30 in a casing configured by fixing a flat front cover 11 to a cup-shaped rear cover 12.

A hollow metal housing 40 is fixed to the front cover 11, and a stator core 21 and a coil 22 constituting the stator 20 are attached to the outer periphery of the housing 40.
In addition, the rotor shaft 31 is rotatably supported in the through hole 41 that penetrates the center portion of the housing 40 via a pair of bearings 50 and 51.
The rotor 30 includes a cup-shaped rotor case 32 in which the base end of the rotor shaft 31 is press-fitted into the bottom surface, and a cylindrical permanent magnet 33 fixed inside the cylindrical wall surface of the rotor case 32. .

Next, a configuration necessary for fixing the housing 40 to the front cover 11 will be described with reference to FIGS. 5 and 6 which are enlarged views of a portion surrounded by an ellipse indicated by a broken line in FIG.
A circular attachment hole 11a is formed at the center of the front cover 11, and a cylindrical attachment portion 42 that fits into the attachment hole 11a is formed at one end in the axial direction of the housing 40, and the attachment portion 42 is attached to the front cover 11. A flange 43 that is in contact with the front cover 11 from the axial direction is formed.

When the housing 40 is fixed to the front cover 11, as shown in FIG. 5, the mounting portion 42 of the housing 40 is fitted into the mounting hole 11 a until the flange 43 contacts the front cover 11, and the front cover of the flange 43 is The outer peripheral side of the mounting portion 42 is crimped in a state where the surface opposite to 11 is held by a jig (not shown).
In this case, the caulking pressure acts as shown by arrows A and B in FIG. 6 to deform the outer peripheral side of the mounting portion 42, and the front cover 11 is sandwiched between the flange 43 and the deforming portion, thereby 40 can be fixed to the front cover 11.
In addition, the brushless motor of such a structure is disclosed by patent document 1, for example.

Japanese Patent Laid-Open No. 11-089196 FIG.

  By the way, in the conventional housing fixing structure described above, when the mounting portion 42 of the housing 40 is crimped and deformed, some of the pressures A and B at the time of crimping become pressures C and D toward the inside, and distortion due to deformation penetrates. As shown in FIG. 6, there is a problem that a protrusion P is generated in the portion of the bearing mounting surface 41 a as it reaches the portion of the bearing mounting surface 41 a of the hole 41. If the generated projecting portion P is left as it is, the bearing 50 cannot be inserted, so that there is a problem that a step of scraping the projecting portion P is required before mounting the bearing.

In this case, if the diameter of the through hole 41 is set in advance larger than the outer diameter of the bearing in anticipation of the occurrence of the protrusion P, the bearing 50 can be inserted without scraping the protrusion P. In this case, there is a problem that the adhesion between the inserted bearing 50 and the housing 40 becomes low, and the attitude of the bearing 50 becomes unstable or the holding force with respect to the bearing is reduced.
In addition, a method of increasing the thickness of the housing 40 so that the deformation strain due to the pressures C and D does not reach the bearing mounting surface 41a, or by forming the bearing mounting surface 41a on the back side of the through hole 41 to enter the through hole 41. Although a method of forming a flank in the portion can be considered, there is a problem that the outer diameter of the housing is increased in the former method, and the size in the axial direction of the housing is increased in the latter method.

  The present invention solves the above-mentioned problems (problems) of the prior art, and it is possible to insert a bearing into the housing without adding a scraping process, and to improve the adhesion between the housing and the bearing. An object of the present invention is to provide a housing fixing structure that can stabilize the attitude of the bearing and obtain a strong holding force by keeping it high, and that does not increase the outer diameter or axial size of the housing.

In order to achieve the above object, the motor housing fixing structure according to claim 1 of the present invention is configured so that one end side in the axial direction of a hollow metal housing in which a through hole through which the rotor shaft passes is formed at the center is formed on the plate. In a structure that is fixed to a cover, a cylindrical mounting portion that fits into a mounting hole formed in the cover on one end side of the housing, and when the cover is fitted to the mounting portion, comes into contact with the cover from the axial direction A flange is formed, a ring-shaped first groove is formed on the end surface perpendicular to the axial direction of the mounting portion, and a ring-shaped second groove is formed on the surface opposite to the surface in contact with the flange cover. Then, with the jig holding the outer peripheral portion of the flange with the jig, the outer peripheral portion of the mounting portion is caulked and deformed, and the cover is deformed between the flange and the mounting portion. By sandwiching between and Characterized by fixing the grayed to cover.

Moreover , as described in claim 2 , it is desirable that the housing is formed of a metal having high thermal conductivity such as brass.

According to the first aspect of the present invention, since the pressure when the outer peripheral portion of the mounting portion is deformed by caulking is absorbed by the groove portion, the thickness of the housing is increased or the bearing mounting surface is moved deeper into the through hole. Even if it is not shifted to the side, the conventional protrusion does not occur in the through hole of the housing. Further, when the flange is held with a jig and caulked, it is possible to prevent a protruding portion from occurring at a portion corresponding to the flange in the through hole.
Therefore, the bearing can be inserted without adding a scraping process or increasing the outer diameter or axial size of the housing, and the inner diameter of the housing can be designed to match the outer diameter of the bearing. By maintaining high adhesion to the bearing, the posture of the bearing can be stabilized and a strong holding force can be obtained.

Further, according to the configuration of claim 2, coupled to as adhesion in height between the bearing and the housing, it is possible to dissipate the heat generated in the bearing during operation of the motor outside efficiently, increase the life of the bearing it is possible.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motor housing fixing structure according to the present invention will be described below with reference to the drawings shown in FIGS. In addition, in each figure, about the structure equivalent to the conventional thing, the same code | symbol as FIGS. 4-6 was attached | subjected and shown.
FIG. 1 is a cross-sectional view showing an outer rotor type DC brushless motor 2 to which a fixing structure according to an embodiment of the present invention is applied.
The DC brushless motor 2 according to the present embodiment is configured by arranging a stator 20 and a rotor 30 in a casing configured by fixing a flat front cover 11 to a cup-shaped rear cover 12.

A hollow housing 40 is fixed to the front cover 11, and a stator core 21 constituting the stator 20 is attached to the outer periphery of the housing 40. A coil 22 wound around a bobbin 23 is attached to the stator core 21. In addition, the rotor shaft 31 is rotatably supported in the through hole 41 that penetrates the center portion of the housing 40 via a pair of bearings 50 and 51. The rotor 30 includes a cup-shaped rotor case 32 in which the base end of the rotor shaft 31 is press-fitted into the bottom surface, and a cylindrical permanent magnet 33 fixed inside the cylindrical wall surface of the rotor case 32. .
In the present invention, the housing 40 is made of a metal having high thermal conductivity such as brass.

  Furthermore, a circuit board 60 on which a drive circuit (not shown) for supplying power to the coil 22 is formed is attached to the outer periphery of the housing 40 in a state parallel to the front cover 11. The circuit board 60 is fixed to a bush 61 fitted in the front cover 11 via a screw 62 on one side which is the lower side in the drawing. A lead wire 64 is connected to the lower end of the circuit board 60 via a connector 63.

Next, the configuration of the present invention necessary for fixing the housing 40 to the front cover 11 will be described with reference to FIGS. 2 and 3 which are enlarged views of a portion surrounded by an ellipse indicated by a broken line in FIG. .
A circular attachment hole 11a is formed at the center of the front cover 11, and a cylindrical attachment portion 42 that fits into the attachment hole 11a is formed at one end in the axial direction of the housing 40, and the attachment portion 42 is attached to the front cover 11. A flange 43 that is in contact with the front cover 11 from the axial direction is formed.
In the present invention, a ring-shaped first groove 42a is formed on the end surface perpendicular to the axial direction of the mounting portion 42, and the surface of the flange 43 opposite to the surface in contact with the front cover 11 is formed. There is a structural feature in that the ring-shaped second groove 43a is formed.

When the housing 40 is fixed to the front cover 11, as shown in FIG. 3, the mounting portion 42 of the housing 40 is fitted into the mounting hole 11 a until the flange 43 comes into contact with the front cover 11. In the state where the surface opposite to 11 is held by a jig (not shown), the outer peripheral side is crimped from the first groove 42 a of the mounting portion 42.
The caulking pressure acts as shown by arrows A and B in FIG. 3 to deform the outer peripheral side of the mounting portion 42 and the outer peripheral side of the flange 43, and the front cover 11 is placed between the flange 43 and the deformed portion. The housing 40 can be fixed to the front cover 11 by being sandwiched between the two.

By the way, in the present invention, as shown in the housing fixing structure of the embodiment of FIG. 3, when the mounting portion 42 of the housing 40 is caulked and deformed, some of the pressures A and B during caulking are inside. However, the deformation distortion due to the pressure is absorbed by the portions of the grooves 42a and 43a and does not reach the portion of the bearing mounting surface 41a of the through hole 41, and a conventional protruding portion is generated. do not do.
Therefore, the bearing 50 can be inserted without adding a scraping process, and the inner diameter of the housing 40 can be designed to match the outer diameter of the bearing. Therefore, by keeping the adhesion between the housing 40 and the bearing 50 high, The attitude of the bearing 50 can be stabilized and a strong holding force can be obtained.

It is sectional drawing which shows the outer rotor type | mold DC brushless motor to which the housing fixing structure of one embodiment of this invention was applied. It is an expanded sectional view before caulking deformation | transformation which shows the inside of the ellipse shown with the broken line of FIG. It is an expanded sectional view after caulking deformation | transformation which shows the inside of the ellipse shown with the broken line of FIG. It is sectional drawing which shows the conventional outer rotor type | mold DC brushless motor. It is an expanded sectional view before caulking deformation | transformation which shows the inside of the ellipse shown with the broken line of FIG. It is an expanded sectional view after caulking deformation which shows the inside of the ellipse shown with the dashed line of FIG.

Explanation of symbols

2 Outer rotor type DC brushless motor 11 Front cover 11a Mounting hole 12 Rear cover 20 Stator 21 Stator core 22 Coil 23 Bobbin 30 Rotor 31 Rotor shaft 32 Rotor case 33 Permanent magnet 40 Housing 41 Through hole 42 Mounting portion 42a First groove 43 Flange 43a Second groove 50, 51 Bearing 60 Circuit board

Claims (2)

In the housing fixing structure of the motor for fixing one end side in the axial direction of a hollow metal housing formed with a through hole through which the rotor shaft passes in the center to a plate-like cover
At one end of the housing, a cylindrical mounting portion that fits into a mounting hole formed in the cover, and a flange that contacts the cover from the axial direction when the cover is fitted into the mounting portion A ring-shaped first groove is formed on an end surface perpendicular to the axial direction of the mounting portion, and a ring-shaped second groove is formed on the surface of the flange opposite to the surface in contact with the cover. There is formed, the said second groove outer peripheral side of the portion from the flange while holding a jig to deform by crimping a portion of the outer peripheral side of the first groove of the mounting portion, the said cover A housing fixing structure for a motor, wherein the housing is fixed to the cover by being sandwiched between a flange and a deformed portion of the mounting portion. The motor housing fixing structure according to claim 1, wherein the housing is made of a metal having high thermal conductivity such as brass .

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