JP2001275299A - Motor bracket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor bracket which can be cut by one-chucking machining with reduce man-hours, the reduced time and cost and has an improved circularlty of its shaft insertion part. SOLUTION: At least three small protrusions 8... are formed on a circular held part 7 which is chucked in cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor bracket.

[0002]

2. Description of the Related Art Generally, as illustrated in FIGS.
The motor bracket 40 includes a cylindrical portion 41, an annular flange portion 42 provided in an outer flange shape at the upper end of the cylindrical portion 41, and an annular flat plate portion 38 provided in a bottom wall shape from the lower end of the cylindrical portion 41, And a center boss 39 having a bearing insertion hole 43 erected at the center of the annular flat plate 38.

When this bracket 40 is used for a motor 45, a bearing insertion hole 43 of a central boss 39 is provided.
A shaft (not shown) is inserted into a bearing press-fitted or bonded and fixed to the shaft to rotatably support the shaft.
A stator (not shown) is attached to the inside (in the case of the outer rotor type, the stator is externally fitted and fixed to the central boss portion 39), and a rotor hub 44 is fixed to one end of a shaft, and the base of various devices such as a hard disk device is mounted. The cylindrical portion 41 is fitted into a fitting hole 47 provided in the 46, and the annular flange portion 42 is fixed to the base 46 with a bolt (not shown). Hard disks 48, 48 (shown by two-dot chain lines)
Are externally fitted to the rotor hub 44. In addition, a rotor magnet is mounted on the rotor hub 44 at a position facing the stator.

[0004] The motor bracket 40 is manufactured by die-casting. Conventionally, the outer peripheral surface 41a of the cylindrical portion 41 is chucked to cut the bearing insertion hole 43 and the like.

[0005]

However, the cylindrical part
When the outer peripheral surface 41a of the 41 is chucked and cut, the chuck pressure, the roundness of the cylindrical portion 41, the thin portion of the connector pocket portion 50 provided at the end face of the annular flat plate portion 38 to the cylindrical portion 41 are obtained.
Under the influence of 51 and the like, the roundness of the bearing insertion hole 43 was deteriorated. Although the roundness is not highly correlated with NRRO (outer ring component), if the roundness is poor, NRR
O (outer ring component) also tends to be worse.

Therefore, as a countermeasure, as shown in FIG. 7A, the inner peripheral surface 41b of the cylindrical portion 41 is chucked with the chuck claws 49, and the outer peripheral surface 41a of the cylindrical portion 41 is mechanically (cut). ), And then, as shown in FIG.
Chucking the outer peripheral surface 41a of the 41 with the chuck claws 49 to machine (cut) the inner peripheral surface 43a of the bearing insertion hole 43 (particularly, the upper and lower bearing house portions into which the bearings are fitted). I made it.

As a result, by processing the outer peripheral surface 41 a of the cylindrical portion 41, the roundness of the cylindrical portion 41 (the outer peripheral surface 41 a) is improved, the influence of distortion due to the chuck is suppressed, and the bearing insertion hole 43 is formed. Roundness has also been improved. However, in the process, it is necessary to chuck the inner peripheral surface 41b and the outer peripheral surface 41a of the cylindrical portion 41, and the number of processes becomes two,
It takes time, time and cost.

Accordingly, the present invention provides a motor for motors that can be cut by one-chucking processing, can improve the roundness of the bearing insertion hole, and does not require much labor, time and cost for cutting. It is intended to provide a bracket.

[0009]

In order to achieve the above-mentioned object, a motor bracket according to the present invention has three or more small projections projecting from a circular gripper to be chucked during cutting. It was established.

With this configuration, since the small projection is chucked instead of the entire surface of the gripped portion, the accuracy (roundness) of the basic circumferential surface of the gripped portion is affected. In addition, the area to be chucked is reduced, and the roundness of a cutting surface such as a bearing insertion hole can be improved.
Eccentricity and fall of the shaft center can be prevented. And N
RRO (outer ring component) can be improved, and when applied to a bracket for a disk rotation motor, a data read / write error for a disk is eliminated. In addition, the time, labor and cost for cutting work are reduced.

[0011] Further, three or more small projections are protruded from a circular gripped portion to be chucked at the time of cutting, and the gripped portion having the small projection is entirely chucked by one chucking. Of the required processing surface.

With this configuration, since the small projection is chucked instead of the entire surface of the gripped portion, the accuracy (roundness) of the basic circumferential surface of the gripped portion is affected. In addition, the area to be chucked is reduced, and the roundness of a cutting surface such as a bearing insertion hole can be improved.
Eccentricity and fall of the shaft center can be prevented. And N
RRO (outer ring component) can be improved, and when applied to a bracket for a disk rotation motor, a data read / write error for a disk is eliminated. In addition, the cutting can be performed by one chucking, and the cutting work is further reduced in labor, time, and cost.

Further, the entirety is made of die-cast, and the small projections are die-cast as-cast.
Therefore, the entire gripped portion including the small projection can be made by as-cast die-casting, and can be easily manufactured at low cost.

In the case where the connector pocket portion is recessed to form a thin portion in the vicinity of the circular gripped portion, the small projection is disposed at a circumferential position avoiding the thin portion. Is what is being done. Therefore, it is possible to avoid a portion which is likely to be locally deformed, and it is not affected by the chuck pressure due to chucking, so that deformation can be prevented.

Further, the cross section of the small projection is a semicircle, a triangle or a quadrangle. Therefore,
The chucking area can be further reduced, and the accuracy (roundness) of the basic circumferential surface of the gripped portion is not affected.
The roundness of the machined surface such as the bearing insertion hole can be further improved, and the eccentricity and fall of the shaft center can be prevented.

A motor bracket having an annular flange portion, wherein the circular gripped portion projects from one surface of the annular flange portion. Therefore, the cutting process of the annular flange portion becomes easy, and it is possible to suppress blurring and rattling during operation of the motor.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing embodiments.

FIG. 1 is an application example showing an embodiment of a motor bracket according to the present invention, FIG. 2 is a bottom view,
FIG. 3 is an explanatory cross-sectional view which also serves as an explanation of a processing step. The bracket 1 includes a cylindrical portion 2, an annular flange portion 3 provided in an outer flange shape at an upper end of the cylindrical portion 2, an annular flat plate portion (bottom wall portion) 12 continuously provided at a lower end of the cylindrical portion 2. Central boss portion having a bearing insertion hole 4 erected at the center of the annular plate portion 12
13 and. The bracket 1 is manufactured by die casting, and thereafter, is subjected to cutting by chucking.

As shown in FIG. 1, when this bracket 1 is used for a motor 5, a shaft (not shown) is inserted into a bearing press-fitted or bonded and fixed to a bearing insertion hole 4 to be rotatable. Support, and further, a stator (not shown) is attached to the inside of the cylindrical portion 2 (in the case of an outer rotor type, the stator is externally fitted to the central boss portion 13), and the rotor hub 6 is fixed to one end of the shaft.
The cylindrical portion 2 is fitted into a fitting hole 47 provided in a base 46 of various devices such as a hard disk device, and the annular flange portion 3 is fixed to the base 46 by bolts (not shown). The hard disks 48 (shown by two-dot chain lines) are externally fitted to the rotor hub 6. Further, a rotor magnet is mounted on the rotor hub 6 at a position facing the stator.

The bracket 1 has three or more small projections 8 projecting from a circular gripped portion 7 that is chucked during cutting. Specifically, a circular gripped portion 7 protrudes from one surface side (the bottom surface 3a side) of the annular flange portion 3. In particular, the gripped portion 7 has a small diameter formed by connecting the outer peripheral surface 2a of the cylindrical portion 2 protruding from the bottom surface 3a of the annular flange portion 3 to a tapered portion which is once reduced in diameter from an upper and lower intermediate position. It is composed of a basic circumferential surface 7a, and small projections 8 formed on the base circumferential surface 7a as ridges.

The gripped portion 7 including the small projection 8 is die-cast as-cast, and the small projection 8 has a rectangular cross-sectional shape as shown in FIG. ) Protruding radially outward from the outer peripheral surface of the gripped portion 7. The tip (one side) of the small projection 8 is a virtual circle C centered on the axis.
It is arranged on the circumference of.

Therefore, the roundness (virtual circle C) can be ensured by chucking the small projections 8 (see FIG. 3A described later) during cutting, and the accuracy (trueness) of the basic circumferential surface 7a can be ensured. Yen)
And the area for chucking is reduced, and the roundness of the bearing insertion hole 4 can be improved. That is, it is possible to prevent eccentricity / falling of the shaft center of the shaft, to improve NRRO (outer ring component), and to eliminate a read / write error for a disk in the case of a hard disk drive.

Further, three or more small projections 8 are formed. If the number of small projections 8 is two or less, the posture becomes unstable during chucking, and the roundness of the bearing insertion hole 4 is poor. This is due to its disadvantages.

The small projections 8 are arranged at circumferential positions avoiding the thin portion 10 (formed by recessing the connector pocket 9 near the gripped portion 7). More specifically, the connector pocket portion 9 is for fitting and attaching a terminal connector (not shown), and is recessed on the outer bottom surface of the cylindrical portion 2. The terminal connector is for connecting a coil wire from the stator to an external device.

The small protrusion 8 is not provided on the radially outward basic circumferential surface 7a of the thin portion 10 serving as the bottom of the connector pocket portion 9. Therefore, at the time of chucking at the time of cutting, the chuck pressure by the chuck claws 49 is not applied to the radially outer side of the thin portion 10, so that it is possible to avoid a portion which is likely to be locally deformed. Deformation can be prevented.

Next, the method of cutting the bracket 1 will be described. As shown in FIG. 3 (a), when the bracket 1 is in the as-cast state, the small projections 8 of the gripped portion 7 are formed. Are chucked by the chuck claws 49. The outer peripheral surface 2 a of the cylindrical portion 2, the bottom surface 3 a of the annular flange portion 3, and the inner peripheral surface 4 a of the bearing insertion hole 4 (particularly, the upper and lower bearing housing portions) are cut. Then, as shown in FIG. 3 (b), the bracket 1 is subjected to the cutting process.

As described above, in one chucking (processing with one chuck), the entire required processing surface (the outer peripheral surface 2a of the cylindrical portion 2, the bottom surface 3a of the annular flange portion 3, and the inner peripheral surface of the bearing insertion hole portion 4). The surface 4a) can be cut, and the man-hour is reduced compared to the conventional two-chucking (see FIG. 7).
Time, work time and cost can be reduced. In addition, since a plurality of necessary processing surfaces can be cut at once, the roundness of the bearing insertion hole 4 can be further improved.

As shown in FIG. 1, when the motor 5 is mounted on the base 46, the outer peripheral surface 2a of the cylindrical portion 2 of the bracket 1 and the bottom surface 3a of the annular flange portion 3 are fixed.
Abuts on the inner peripheral surface 47a and the upper surface 47b of the fitting hole 47, but since it is precisely cut, it is possible to prevent the occurrence of shake and rattling during operation of the motor 5, The occurrence of read / write errors in the hard disk 48 driven by the drive 5 is effectively avoided.

As shown in FIG. 1, the gripped portion 7 (small projection 8) which does not require cutting is provided on the inner peripheral surface 47 of the fitting hole 47.
Since the diameter is reduced from the upper half part of the outer peripheral surface 2a of the cylindrical part 2 which is in contact with a, there is no inconvenience in attachment to the base 46. In addition, since the gripped portion 7 is housed in the fitting hole 47 of the base 46, there is no need to cut it off, and the gripped portion 7 does not cause an increase in the axial dimension of the motor 5. .

Next, FIG. 4 shows another embodiment of the small projections 8, and the following configuration is clearly different from FIG. That is, as shown in FIG. 4, the projecting shape of the small protrusion 8 outward in the radial direction is formed in a triangle when viewed from the lower surface, and the vertex (tip) of the triangle is on the circumference of the virtual circle C. It is arranged. Therefore, positioning can be performed reliably during chucking, and the roundness of the bearing insertion hole 4 is further improved.

FIG. 5 shows another embodiment of the small projection 8, and the following configuration is clearly different from FIG. That is, as shown in FIG. 5, the projecting shape of the small projection 8 outward in the radial direction is formed in a semicircle when viewed from the lower surface, and the semicircle is arranged so as to be inscribed in the circumference of the virtual circle C. Has been established. Therefore, when the chuck 1 is chucked, the bracket 1 has strength enough to withstand the chuck pressure by the chuck pawls 49, and the deformation of the bracket 1 can be prevented.

The overall shape of the bracket 1 and the position of the gripped portion 7 are not limited to the above-described embodiment.
The design can be changed without departing from the gist of the present invention.

[0033]

According to the present invention, since the small projections 8 are chucked instead of the entire surface of the gripped portion 7, the accuracy of the basic circumferential surface of the gripped portion 7 (roundness) ), The area for chucking is reduced, and the roundness of the machining surface such as the bearing insertion hole 4 can be improved.
Eccentricity and fall of the shaft center can be prevented. And N
RRO (outer ring component) can be improved, and when this motor bracket is used in a hard disk drive, a read / write error on the disk is eliminated. That is, cutting can be performed by one chucking process, and the roundness of the processed surface can be improved, so that the cutting process does not require much labor, time, or cost.

[Brief description of the drawings]

FIG. 1 is a side view also serving as an application example showing an embodiment of the present invention.

FIG. 2 is a bottom view of the bracket.

FIG. 3 is an explanatory cross-sectional view also serving as an explanation of a processing step.

FIG. 4 is a bottom view showing another embodiment.

FIG. 5 is a bottom view showing another embodiment.

FIG. 6 is a side view showing a use state of a conventional bracket.

FIG. 7 is an explanatory cross-sectional view which also serves as a description of a conventional bracket processing step.

[Explanation of symbols]

 3 Annular flange part 7 Grabbed part 8 Small protrusion 9 Connector pocket part 10 Thin part

Claims (6)

[Claims] 1. A motor bracket comprising three or more small projections projecting from a circular gripped portion that is chucked during cutting. 2. A circular grip portion to be chucked at the time of cutting is provided with three or more small projections projecting therefrom, and the grip portion having the small projection portion is entirely chucked by one chucking. A motor bracket characterized by cutting the required processing surface. 3. The motor bracket according to claim 1, wherein the whole small-sized projection is die-cast as-cast. 4. A thin portion is formed by recessing a connector pocket portion in the vicinity of the circular gripped portion, and the small protrusion is disposed at a circumferential position avoiding the thin portion. The motor bracket according to claim 1, 2 or 3. 5. The motor bracket according to claim 1, wherein the cross section of the small projection is a semicircle, a triangle, or a square. 6. A motor bracket having an annular flange portion, wherein the circular gripped portion protrudes from one surface side of the annular flange portion.
Motor bracket as described.