JP2003230249A - Motor, its assembly method, and information record reproducing equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor which does not do a fatal damage to an information converting element or a member, etc., such as a land, etc., without a rotor coming off a bearing when it is subjected to strong shock. <P>SOLUTION: A ball bearing 11 is fitted around a bearing sleeve 8, and a rotary magnet 16 united with a slip-stop member 15 is fixed via a slip-stop retaining member 14 to the bottom of a one-way rotary disc 6, and in condition that the bottom of the flange part 7 of the bearing sleeve 8 and the top of the lower flange part of the slip-stop member 15 face each other across the ball bearing 11, a rotary column is inserted into a bearing part 10 thereby being supported rotatably. A rotor 19 never slips out of the bearing part 10 even by the strong shock caused by fall or the like by setting the interval between the bottom of the flange part 7 of the bearing sleeve 8 and the top of the lower flange of the slip-stop member 15 so as to be 'the diameter of the ball of the ball bearing + minimum dimension'. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin and small motor used in a magnetic disk device, an optical disk device and the like, and a disk type information recording / reproducing device using the same.

[0002]

2. Description of the Related Art First, a conventional motor and information recording / reproducing apparatus will be described with reference to the drawings.

FIG. 10 is a schematic sectional view showing the structure of the main part of a conventional motor and information recording / reproducing apparatus.

In FIG. 10, the rotary shaft portion 102 is fixed to the rotary table 101 by a method such as press fitting.
On the lower surface of the flange portion 103 of No. 01, the rotor yoke 104
A rotary magnet 105, which is magnetized to have a plurality of poles, is fixed to the rotor via a rotor, and a rotor (rotor) 106 is formed by these.

On the other hand, a ring-shaped bearing sleeve 107 having an outer peripheral surface of the rotary shaft portion 102 of the rotor 106 and an inner peripheral surface in which a minute gap is formed is formed with one end sealed by a thrust support plate 108. , The bearing sleeve 107 and the thrust support plate 1 which are fixed to the base 109.
The bearing portion 110 configured to support the shaft portion including the rotation shaft portion 102 is configured by 08, and the rotation shaft portion 102 of the rotor 106 is inserted into the recess formed in the bearing portion 110, and the rotation shaft portion 102 and the bearing sleeve 107. And thrust support plate 1
A dynamic pressure lubricant 111 such as an ester-based synthetic oil is filled in a minute gap between the 08. Further, a stator (stator) 1 in which a coil 113 is wound around an iron core 112
14 is fixed to the base 109 by a method such as press fitting or adhesion, and the rotating magnet 105 and the iron core 112 around which the coil 113 is wound are arranged so as to face each other. A thrust suction plate 120 is fixed to the base 109 so as to face the lower end surface of the rotary magnet 105 in the axial direction.

A thrust bearing portion is formed by providing a dynamic pressure generating groove (not shown) on the upper surface of the thrust support plate 108 facing the lower end surface of the rotary shaft portion 102 of the rotor 106. Also,
A dynamic pressure generating groove (not shown) is formed on the inner peripheral surface of the bearing sleeve 107 facing the outer peripheral surface of the rotating shaft portion 102 of the rotor 106.
To form a radial bearing portion, and the thrust bearing portion and the radial bearing portion constitute a so-called fluid bearing,
By supplying an electric current to the coil 113, the rotating magnet 105 rotates, that is, the rotor 106 rotates, as is well known.
Due to the rotation of the rotary shaft portion 102 of the rotor 106, a dynamic pressure is generated in the dynamic pressure lubricant 111, and the rotary shaft portion 102 receives the dynamic pressure in the radial direction and the axial direction, so that the rotor 106 is smoothly rotated around the rotation center 1. Is rotated to
Disk drive motor 11 suitable for information recording / reproducing apparatus
5 is formed.

Plane 11 on which the information recording medium layer is formed
A disc-shaped recording medium (hereinafter referred to as a disc) 117 having 6 is placed on the upper surface of the flange portion 103 of the rotary base 101, and the clamp member 118 tightens the screw 119 to move the disc 117 to the flange portion 1 of the rotary base 101.
It is pressed against 03 and fixed. A disk 115 is rotated by a motor 115 and an information conversion element such as a magnetic head (not shown) mounted on a slider or an optical pickup (not shown) equipped with an objective lens for condensing light is well known. An information recording / reproducing apparatus is configured by performing recording / reproducing on the disk 117 by the method.

[0008]

In recent years, various information devices have been widely used, and there is an increasing need to increase the recording capacity of disks, and efforts to increase recording density have been made. In addition to being strengthened, the demand for smaller and thinner devices is increasing. Furthermore, as the device becomes smaller and thinner, the environment in which the device is used expands, and the frequency with which the device is carried is increasing, and it is preferable for the device to drop or collide with other objects. There are no opportunities to increase.

However, in the motor used in the above-mentioned conventional device, if the device is dropped, or if an excessive shock or vibration due to a collision with another object or vibration during carrying is carried, the motor will rotate. The rotor floats against the holding force due to the attraction force between the magnet and the thrust attraction plate facing it, or in an extreme case, the rotor may come out of the fluid bearing portion.

When the rotor floats or comes off, a member (for example, a lamp) that supports the information conversion element arranged on the disk with a minute gap.
There is a problem that the information conversion element and the disk collide with each other, the recorded disk and the member supporting the information conversion element (for example, suspension) are damaged, or normal recording and reproduction cannot be performed.

In order to solve such a problem, the rotor comes off,
With regard to prevention of floating, by arranging a retainer and a suction magnet, even if vibration or shock is applied, the attraction force of the suction magnet prevents the lift and the retainer slides on the bearing against excessive shock. A technique has been proposed in which the contact is surely prevented from coming off (eg, Japanese Patent Laid-Open No. 11-55900).

However, even when such a technique is used, when excessive vibration or shock is applied and the retaining member slides on the bearing, the information conversion element and the disk collide with each other and the disk or the information conversion element or the information conversion element. A member that supports the element (for example, land, suspension, etc.) may be fatally damaged, or the rotation of the rotating body may be stopped momentarily or the rotation speed may be slowed down due to sliding contact. The problem is that rotation is blocked and normal recording and reproduction cannot be performed.

The present invention solves the above problems and provides a retaining contact member on the outer peripheral portion of a bearing sleeve, and prevents the retaining member provided on the disk part from retaining contact member and rotation axis. By forming a minute gap in the direction, while preventing the rotor from coming off while keeping the small size and thin shape, the collision displacement amount when the disk and the information conversion element collide is suppressed to a small value. An object of the present invention is to provide a motor that is useful for downsizing and that is thin, capable of maintaining smooth rotation of a rotating body without causing fatal damage to a member or the like that supports the motor.

[0014]

In order to achieve this object, a motor of the present invention is a motor having a stator around which a coil is wound and a rotary magnet magnetized to have a plurality of poles which are arranged to face the stator. A retaining member affixed to a bearing sleeve of a bearing portion that rotatably supports a shaft portion composed of a rotating columnar portion or a rotating shaft portion; and a rotor having a rotor yoke composed of a retaining member and a retaining member. And the lower surface of the flange portion of the bearing sleeve and the upper surface of the lower flange portion of the retaining member face each other with the retaining contact member sandwiched therebetween.

With this configuration, it is possible to limit the amount of deviation (movement) of the rotating body upward in the direction of the rotation center axis due to impact caused by dropping, collision with another object, or excessive vibration during movement. , The rotating body does not come out of the bearing part, and the collision displacement amount when the disk and the information conversion element collide is suppressed to a small extent, which causes fatal damage to the information conversion element and members supporting the information conversion element. It is possible to realize a motor with no problem.

In order to achieve this object, the motor of the present invention is a motor structure in which the retaining member fixed to the bearing sleeve is a ball bearing composed of a retainer having a ball insertion hole and a ball. Have.

With this structure, the bearing sleeve moves upward in the direction of the center axis of rotation of the rotating body due to an impact caused by a drop, a collision with another object, or excessive vibration during movement, etc., and sandwiches the ball of the ball bearing. When the lower surface of the flange part of and the upper surface of the lower flange part of the retaining member come into contact with the ball bearings respectively, the balls of the ball bearing are placed between the lower surface of the flange part of the bearing sleeve and the upper surface of the lower flange part of the retaining member. The interposition prevents the rotation of the rotating body from being hindered, and has the effect that smooth rotation can be maintained.

In order to achieve this object, in the motor of the present invention, the retainer of the ball bearing has a horizontal portion having a ball insertion hole and a vertical portion on at least one side of the horizontal portion. The diameter d of the ball insertion hole provided in is D = the diameter t of the ball of the ball bearing t = the thickness of the horizontal portion having the ball insertion hole of the retainer of the ball bearing δ = the highest point of the ball of the ball bearing and the bearing sleeve Assuming a distance from the lower surface of the flange portion, it is in a range satisfying 2 [(t + δ) {D- (t + δ)} ^1/2 <d <D, and at least one vertical portion of the horizontal portion The height H is H = δ + D / 2 + (D ² −d ² ) ^1/2 + t.

With this structure, when the ball bearing is fitted into the bearing sleeve, the upper end surface of the vertical portion of the retainer of the ball bearing is positioned so as to abut against the lower surface of the flange portion of the bearing sleeve. It has the effect of being able to position.

To achieve this object, in the motor of the present invention, the distance between the lower surface of the flange portion of the bearing sleeve and the upper surface of the lower flange portion of the retaining member is a predetermined distance D + α, where D = the ball bearing The diameter α of the ball is set to be a minute size.

With this configuration, the amount of deviation (movement) of the rotating body in the upper direction of the rotation center axis due to impact caused by dropping, collision with another object or excessive vibration during movement is limited. Thus, it is possible to realize a motor that does not cause fatal damage to the information conversion element and the members that support the information conversion element.

Further, in order to achieve this object, the motor of the present invention has a structure in which a small dimension α at a predetermined distance is α <50 μm.

With this configuration, when the disk and the information conversion element collide with each other due to a shock caused by a drop, a collision with another object, or excessive vibration during movement, the displacement amount due to the collision is suppressed to a very small value, and the information conversion is performed. It is possible to realize a motor that does not cause fatal damage to members supporting the elements and the information conversion element.

To achieve this object, in the motor of the present invention, the retaining contact member fixed to the bearing sleeve has a plurality of annular shapes, and one end surface thereof has a flat surface perpendicular to the center of rotation. The contact ring is a retaining ring provided with a protrusion.

With this structure, even if the rotor is moved upward in the direction of the rotation center axis of the rotor due to an impact caused by a drop, a collision with another object, or excessive vibration during the movement, the dropout provided in the rotary disk. The stopper does not come out of contact with the retaining contact ring fixed to the bearing sleeve to prevent the rotor from slipping out of the bearing, and the collision displacement amount when the disk and the information conversion element collide is suppressed to a small level. It is possible to realize a motor that does not cause fatal damage to the information conversion element and the members that support the information conversion element.

In order to achieve this object, in the motor of the present invention, the gap between the small plane of the protrusion of the retaining ring and the retaining member opposed thereto in the rotation axis direction is a predetermined minute amount. It has a configuration that is dimensioned.

With this configuration, the amount of deviation (movement) of the rotating body upward in the direction of the rotation center axis due to impact caused by dropping, collision with another object, or excessive vibration during movement is limited. Thus, it is possible to realize a motor that does not cause fatal damage to the information conversion element and the members that support the information conversion element.

Further, in order to achieve this object, the motor of the present invention has a structure in which the predetermined minute dimension β is β <50 μm.

With this configuration, when the disc and the information conversion element collide with each other due to an impact caused by a drop, a collision with another object, or excessive vibration during movement, the displacement amount due to the collision is suppressed to a very small value, and the information conversion is performed. It is possible to realize a motor that does not cause fatal damage to members supporting the elements and the information conversion element.

Further, the motor assembling method of the present invention is a method of assembling a motor having a stator around which a coil is wound and a rotating magnet magnetized to have a plurality of poles facing the stator. The first step of fixing the retaining contact member to the bearing sleeve of the bearing portion that rotatably supports the shaft portion made of and the magnetic force acting between the retaining member and the rotating magnet It has a second step of adhering a retaining member fixed to a rotatably assembled rotating disk and a rotating magnet to which a retaining member having a substantially crank-shaped cross section is fixed.

By this method, the magnetic attraction force of the retaining member and the rotating magnet is used to bond the rotating magnet integrated with the retaining member, so that the information recording medium layer of the rotating disk is damaged. The rotating magnet integrated with the retaining member can be easily bonded, and the retaining member is secured along the inner peripheral surface of the retaining member that is fixed so that the inner peripheral surface is concentric with the rotation center. Since the outer peripheral surface of the member is guided and positioned so as to be fitted, it is possible to manufacture a motor in which the concentricity with respect to the rotation center of the rotary magnet is easily ensured.

Further, in order to achieve this object, the information recording / reproducing apparatus of the present invention has a configuration in which the motor according to any one of claims 1 to 8 is mounted.

With this configuration, it is possible to limit the amount of deviation (movement) of the rotating body upward in the direction of the rotation center axis due to impact caused by dropping, collision with another object, or excessive vibration during movement. , The rotating body does not come out of the bearing part, the collision displacement amount when the disk and the information conversion element collide is suppressed to be small, and the information conversion element and the member supporting the information conversion element are fatally damaged. It is possible to realize a non-information recording / reproducing apparatus.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view showing an outline of the structure of a main part of a motor used in an information recording / reproducing apparatus according to Embodiment 1 of the present invention. In FIG.
A disk portion 4 in which an information recording medium layer 3 is formed on a main plane 2 perpendicular to the axial direction of the rotation center 1 and a solid cylindrical rotating cylinder portion 5 on the opposite side of the main plane 2 are integrally formed. A rotating disk 6 is formed. The disc portion 4 and the rotating column portion 5 are integrally formed by individually molding members.
The rotating disk 6 may be formed integrally by a method such as adhesion with an adhesive or heat fusion. The rotary disk 6 has an inner peripheral surface that forms a minute gap with the outer peripheral surface of the rotary columnar portion 5, and the flange portion 7 is provided at one end on the rotary disk 6 side.
Bearing portion for fixing a shaft portion composed of the rotating columnar portion 5 to which a thrust support plate 9 is fixed so as to seal one end of the T-shaped hollow cylindrical bearing sleeve 8 opposite to the flange portion 7. 10 are configured. Further, a ball bearing 11 as a retaining contact member is provided on the outer peripheral portion of the bearing sleeve 8.
Is fitted by a method such as loose press-fitting or adhesion. Here, the bearing sleeve 8 and the thrust support plate 9 may be integrally formed to form the bearing portion 10.

As shown in a partially enlarged view of FIG. 2, the bearing portion 1
The rotary cylinder portion 5 of the rotary disk 6 is inserted into the concave portion of 0, and a dynamic pressure lubricant 201 such as ester synthetic oil is filled in a minute gap between the rotary cylinder portion 5 and the bearing portion 10. There is.

A radial pressure bearing groove 1 is formed by forming a dynamic pressure generating groove (not shown) on either the outer peripheral surface of the rotary columnar portion 5 of the rotary disk 6 or the inner peripheral surface of the bearing sleeve 8 of the bearing portion 10.
2 is formed, and a dynamic pressure generating groove (not shown) is formed on either the lower end surface of the rotary columnar portion 5 or the upper surface of the thrust support plate 9 to configure the thrust bearing portion 13. Together with this, it constitutes a so-called fluid bearing.

Further, a circular ring-shaped recess made of a magnetic material is formed on the surface of the disk portion 4 of the rotary disk 6 opposite to the main plane 2, that is, on the surface of the rotary cylinder portion 5 (hereinafter referred to as the lower side of the rotary disk 6). The stop holding member 14 is fixed. On the other hand, the cross section of the hollow cylinder, which is made of magnetic material, has an upper flange that extends radially outward at the upper end of the hollow cylinder, and a lower flange that extends radially inward at the lower end of the hollow cylinder. The ring-shaped rotary magnet 16 magnetized to have a plurality of poles is press-fitted or adhered to the outer peripheral surface of the vertical portion of the retaining member 15 having a shape, or is adhered to the lower surface of the upper flange portion of the retaining member 15. The rotating magnet 16 is fixed by the method and is integrated with the retaining member 15 in a state where the outer peripheral surface of the upper flange portion of the retaining member 15 is fitted to the inner peripheral surface 17 of the retaining member 14. Has its upper surface fixed to the lower surface of the retaining member 14 by adhesion or the like. Here, the distance between the lower surface of the flange portion 7 of the bearing sleeve 8 and the upper surface of the lower flange portion of the retaining member 15 facing the flange portion 7 is a predetermined dimension, that is, (the diameter of the ball of the ball bearing 11) + (a minute dimension). Is set to have. Furthermore, it is desirable to set the minute dimension to 50 μm or less. The retaining member 14 and the retaining member 15 constitute a rotor yoke 18 for the rotating magnet 16, and the rotating disk 6, the rotor yoke 18 and the rotating magnet 16 constitute a rotating body 19.

A bearing portion 10 for rotatably supporting a shaft portion composed of the rotating columnar portion 5 is fixed to a base 20 by press fitting or adhesion, and a coil 22 is wound around each of a plurality of magnetic pole teeth of an iron core 21. The stator 23 is fixed to the base 20 by a method such as press fitting, and the rotating magnet 16 and the coil 22 are attached.
The iron cores 21 wound with are arranged so as to face each other.
Further, an annular thrust suction plate 24 made of a soft magnetic material is fixed to the base 20 so as to face the lower end surface of the rotary magnet 16 in the axial direction, and a magnetic attraction force acting between the rotary magnet 16 and the rotary magnet 16 causes the rotor to rotate. 19 is pulled toward the thrust support plate 9 side along the direction of one axis of rotation.

As is well known, by supplying an electric current to the coil 22, the rotating magnet 16 or the rotating disk 6 rotates, and the rotation of the rotating columnar portion 5 generates a dynamic pressure in the dynamic pressure lubricant 201, and the bearing portion 10 Further, the rotary disk 6 is subjected to dynamic pressure in the radial direction and the axial direction, so that the rotary disk 6 is smoothly rotated around the rotation center 1.

A thrust suction plate 24 is provided so as to face the lower end surface of the rotating magnet 16, and a dynamic pressure lubricant 201 is filled in a gap formed by the recess of the bearing portion 10 and the rotating columnar portion 5 of the rotating disk 6. By doing so, regardless of any attitude difference of the information recording / reproducing apparatus, the rotating columnar portion 5 of the rotating disk 6 has the magnetic force between the rotating magnet 16 and the thrust attraction plate 24 and the atmospheric pressure around the rotating disk 6. The dynamic pressure lubricant 201 itself does not come off from the concave portion of the bearing unit 10 due to the received pressure, and the dynamic pressure lubricant 201 itself is viscous or surface tension.
Does not flow out and the dynamic pressure lubricant 201 disappears. Even during the rotation of the rotary disc 6, the dynamic pressure of the dynamic pressure lubricant 201 generated and the own weight of the rotary disc 6, the rotary magnet 16 and the thrust suction plate 24. It rotates smoothly in balance with the magnetic force between and the atmospheric pressure around it.

When the rotating body 19 moves upward in the axial direction around the rotating shaft due to an impact caused by dropping of the device, collision with another object, or excessive vibration during movement, the flange portion 7 of the bearing sleeve 8 is moved. The upper surface of the lower flange portion of the retaining member 15 facing the lower surface of the abutment abuts on the ball of the ball bearing 11 fitted in the bearing sleeve 8, and further the rotating body 19
At the same time, the balls of the ball bearing 11 move upward and come into contact with the lower surface of the flange portion 7 of the bearing sleeve 8, so that the rotating body 19 does not slip out of the bearing portion 10, and the lower surface of the flange portion 7 of the bearing sleeve 8 is prevented. Since the balls of the ball bearing 11 are interposed between the upper surface of the lower flange portion of the retaining member 15 and the upper surface of the lower flange portion, the rotation of the rotating body 19 is not hindered.

Next, the outline of the shape of the ball bearing 11 as the retaining member and the positional relationship between the bearing sleeve 8 and the retaining member 15 will be described. FIG. 3 is a schematic cross-sectional arrow view seen from the rotation center 1 side, which is a cross section taken along a plane including a radial line passing through the center of the ball of the ball bearing 11 and the rotation center 1. As shown in FIG.
The ball bearing 11 has a U-shaped retainer 31 having a vertical section on both sides of a horizontal section and a ball insertion hole 3 of the U-shaped retainer 31.
The ball insertion hole 32 has a simple structure in which the ball 33 is simply placed on the ball 2. The diameter of the ball insertion hole 32 is set so that the ball 33 slightly protrudes from the lower surface of the retainer 31 through the ball insertion hole 32. In FIG. 3, eight balls 3
3 shows that the balls 3 are arranged at substantially equal intervals.
The number of 3 is not limited to eight. To further explain with reference to FIG. 1, the distance between the lower surface of the flange portion 7 of the bearing sleeve 8 and the upper surface of the lower flange portion of the retaining member 15 facing the lower surface of the flange portion 7 is such that the balls of the ball bearing 11 fitted in the bearing sleeve 8 are spaced apart from each other. When the value is set to a value obtained by adding a minute dimension (for example, α is the minute dimension) to the diameter of,
Upper end face edge 34 of ball insertion hole 32 of retainer 31
With the ball 33 in contact with, the distance between the point of the ball 33 closest to the lower surface of the flange portion 7 of the bearing sleeve 8 and the lower surface of the flange portion 7 of the bearing sleeve 8 (for example, δ) is The ball bearing 11 is fitted to the bearing sleeve 8 at a position smaller than the above-mentioned minute dimension α. In addition, the diameter d of the ball insertion hole 32 is set so that the minute distance (for example, ε) that the ball 33 protrudes from the lower surface of the retainer 31 through the ball insertion hole 32 is slightly larger than the above distance δ. The distance δ is set so that the upper surface of the lower flange portion of the retaining member 15 facing the lower surface of the flange portion 7 of the bearing sleeve 8 does not abut the ball 33 and a minute gap exists.
The diameter d of the ball insertion hole 32 is set. However, the diameter d is smaller than the diameter D of the ball of the ball bearing 11 (that is, d <D). Here, the bearing sleeve 8
Lower surface of the flange portion 7 and the retaining member 1 facing it
The distance between the upper surface of the lower flange portion of No. 5 and the upper surface of the bearing sleeve 8
It is desirable that the ball bearings 11 fitted in the space be set to have a diameter equal to the diameter of the balls plus 50 μm or less. Here, the vertical portions on both sides of the retainer 31 do not have to have the same height on both sides, and need not be on both sides, but may be on either one.

The shape of the ball bearing 11 for facilitating the positioning of the ball bearing 11 fitted in the bearing sleeve 8 will be described with reference to FIG. In FIG. 4, the height of the vertical portion of the retainer 41 having a U-shaped cross section is H, the diameter of the ball insertion hole 42 in the horizontal portion is d,
Retainer 41 of horizontal part where ball insertion hole 42 is formed
Is t, the diameter of the ball 43 is D, the uppermost point of the ball 43 and the retainer 41 when the ball 43 is in contact with the upper end edge 44 of the ball insertion hole 42 of the retainer 41.
The distance from the upper end surface of the vertical portion of the ball 43, that is, the distance between the uppermost point of the ball 43 and the lower surface of the flange portion 7 of the bearing sleeve 8 is δ,
Upper end face edge 44 of ball insertion hole 42 of retainer 41
The distance between the lowest point of the ball 43 and the upper surface of the lower flange portion of the retaining member 15 when the ball 43 is in contact with is ε, and the distance of the ball 43 protruding from the lower surface of the retainer 41 through the ball insertion hole 42. The protrusion amount is ΔD, and the distance between the lower surface of the flange portion 7 of the bearing sleeve 8 and the upper surface of the lower flange portion of the retaining member 15 facing the lower surface is (D +
If it is set to α), the rotating body 19 is set to the center of rotation 1
When the ball 43 of the ball bearing 11 is sandwiched between the upper surface of the lower flange portion of the retaining member 15 and the lower surface of the flange portion 7 of the bearing sleeve 8 by moving upward in the axial direction of the lower portion of the retaining member 15, The upper surface of the flange portion does not contact the retainer 41 but remains in contact with the ball 43,
On the other hand, from the condition that the ball 43 does not fall out of the retainer 41, δ <ΔD <D / 2−t (1) On the other hand, ΔD = D / 2− (D ² −d ² ) ^1/2 / 2−t (2) From equations (1) and (2), 2 [(t + δ) {D- (t + δ)}] ^1/2 <d <D (3) On the other hand, α = δ + ε (δ> 0, ε> 0) (4) The above δ and ε (= α−δ) are set so that the balls 43 of the ball bearing 11 do not come into contact with the upper surface of the lower flange portion of the retaining member 15 and the lower surface of the flange portion 7 of the bearing sleeve 8 during normal rotation. Then, the diameter D of the ball 43
And retainer 4 in the horizontal part where ball insertion hole 42 is formed
From the thickness t of 1, the diameter d of the ball insertion hole 42 is set by the above equation (3). Next, the height H of the vertical portion of the retainer 41 is determined by the following equation (5).

H = δ + D / 2 + (D ² −d ² ) ^1/2 + t (5) The diameter d of the ball insertion hole 42 is set by the above equation (3), and the vertical portion of the retainer 41 is set by the equation (5). The height H is determined and the shape of the retainer 41 is determined.
3 is placed in the ball insertion hole 42 of the retainer 41, and is loosely press-fitted onto the outer peripheral surface of the bearing sleeve 8 so that the upper end surface of the vertical portion of the retainer 41 contacts the lower surface of the flange portion 7 of the bearing sleeve 8. , A gap of δ is secured between the uppermost point of the ball 43 and the lower surface of the flange portion 7 of the bearing sleeve 8, and between the upper surface of the lower flange portion of the retaining member 15 and the lowermost point of the ball 43. A gap is secured. In FIG. 4, the heights of the vertical portions on both sides of the retainer 41 are shown to be the same, but they are not set to the same height, and even if one of the vertical portions is set to the above-described height H. It goes without saying that the vertical portions need not be provided on both sides of the horizontal portion, but may be provided on either side.

In the above-described embodiment, a so-called radial gap (circumferentially facing) type brushless motor is used. However, as shown in FIG. 5, a so-called axial gap (face-facing) type brushless motor is used. Needless to say, it may be formed by. Here, FIG. 5 is a schematic sectional view showing an example of a main part of the axial gap type brushless motor. The same reference numerals as those in FIG. 1 are attached to the same items as those to which the reference numerals shown in FIG. 1 are added. In FIG. 5, the difference from the configuration of the main part of the radial gap type brushless motor described above is that the retaining member 51 for preventing slipping off is provided on the lower surface of the rotating disk 6.
Is fixed by a method such as adhesion, while the ring-shaped rotary magnet 52 magnetized to have a plurality of poles is press-fitted onto the outer peripheral surface of the vertical portion of the retaining member 53 having a substantially crank-shaped cross section similar to that of FIG. It is fixed by a method such as bonding or by a method such as bonding to the lower surface of the upper flange portion of the retaining member 53, and the upper portion of the retaining member 52 is attached to the inner peripheral surface of the retaining member 51 as in FIG. With the outer peripheral surface of the flange portion fitted, the upper surface of the rotary magnet 52 integrated with the retaining member 53 is fixed to the lower surface of the retaining member 51 by adhesion or the like, and retaining retaining The member 51 and the retaining member 53 form a rotor yoke 54. The rotating disk 6, the rotor yoke 54 and the rotating magnet 52 constitute a rotating body 55, and on the other hand, a stator 58 in which a plurality of substantially triangular coils 57 are wound on a printed wiring board 56 is fixed to a base 59. The rotating magnet 52 and the coil 57 are arranged so as to face each other with a gap in the axial direction. A ball bearing 11 is fitted on the outer peripheral surface of the bearing sleeve 8, and the flange portion 7 of the bearing sleeve portion 8, the ball bearing 11 and the retaining member 53 are arranged in the same manner as in FIG. Is omitted.

Further, unlike the above-described embodiment, the rotating disk does not have a shape that constitutes a part of the motor, but the motor as in the conventional example shown in FIG. 10 and the disk-shaped recording medium are separately configured. Can also be applied to. FIG. 6 is a schematic cross-sectional view showing an example of an information recording / reproducing apparatus in which a motor and a disk are individually configured and a main part of the motor. The same reference numerals as those in FIG. 1 are attached to the same items as those to which the reference numerals shown in FIG. 1 are added. Figure 6
In the above, the rotary shaft portion 6 is attached to the rotary base 61 by a method such as press fitting.
2 is fixed, and a retaining member 64 made of a magnetic material is fixed to the lower surface of the flange portion 63 of the rotary table 61 by a method such as adhesion. A flange of the T-shaped hollow cylindrical bearing sleeve 8 having an outer peripheral surface of the rotary shaft portion 62 of the rotary table 61 and an inner peripheral surface in which a minute gap is formed, and having a flange portion 7 at one end on the rotary table 61 side. A thrust support plate 9 is fitted so as to seal one end on the side opposite to the portion 7, and constitutes a bearing portion 10 that axially supports a shaft portion composed of a rotary shaft portion 62. Further, a ball bearing 11 as a retaining member for retaining is fitted on the outer peripheral portion of the bearing sleeve 8 by a method such as loose press-fitting or adhesion.

Similar to FIG. 2 in the above embodiment,
The rotary shaft portion 62 of the rotary table 61 is inserted into the concave portion of the bearing portion 10, and a small gap between the rotary shaft portion 62 and the bearing portion 10 is provided.
For example, a dynamic pressure lubricant such as an ester synthetic oil is enclosed, and a dynamic pressure generation groove is formed on either the outer peripheral surface of the rotary shaft portion 62 of the rotary base 61 or the inner peripheral surface of the bearing sleeve 8 of the bearing portion 10. To form the radial bearing portion, and the rotary shaft portion 6
A thrust bearing portion is formed by forming a dynamic pressure generating groove on either the lower end surface of 2 or the upper surface of the thrust support plate 9, and constitutes a so-called hydrodynamic bearing together with a dynamic pressure lubricant.

On the other hand, the upper end of the hollow cylinder, which is made of a magnetic material, has an upper flange portion extending radially outward,
The ring-shaped rotary magnet 1 is magnetized into a plurality of poles on the outer peripheral surface of the vertical portion of the retaining member 15 having a substantially crank-shaped cross section, which has a lower flange portion extending inward in the radial direction at the other lower end portion.
6 is fixed to the lower surface of the upper flange portion of the retaining member 15 by a method such as press fitting or bonding, and the outer peripheral surface of the upper flange portion of the retaining member 15 is a retaining member 64. The upper surface of the rotary magnet 16 integrated with the retaining member 15 is fixed to the lower surface of the retaining member 64 by adhesion or the like in a state of being fitted to the inner peripheral surface of the retaining member 15. Here, the lower surface of the flange portion 7 of the bearing sleeve 8 and the retaining member 15 facing the lower surface
The distance from the upper surface of the lower flange portion is the same as in the above-described embodiment, and is set to have (the diameter of the ball of the ball bearing 11 + a minute dimension). The retainer holding member 64 and the retainer member 15 constitute a rotor yoke 65 for the rotary magnet 16, and the rotary base 61, the rotary shaft portion 62, the rotor yoke 65 and the rotary magnet 16 constitute a rotary body 66.

The bearing portion 10 for supporting the shaft portion composed of the rotary shaft portion 62 is fixed to the base 67 by press fitting or adhesion, and the coil 22 is wound around each of the plurality of magnetic pole teeth of the iron core 21. The stator 23 is fixed to the base 67 by a method such as press fitting, and the rotating magnet 16 and the coil 22 are attached.
The iron cores 21 wound with are arranged so as to face each other.
An annular thrust suction plate 24 made of a soft magnetic material is fixed to the base 67 so as to face the lower end surface of the rotary magnet 16 in the axial direction.

By supplying an electric current to the coil 22, the rotating body 66 is smoothly rotated around the rotation center 1 as is well known, thus forming a motor suitable for an information recording / reproducing apparatus or the like.

The disc 602 having a flat surface on which the information recording medium layer 601 is formed is the flange portion 6 of the turntable 61.
3 is mounted on the upper surface of the clamp member 603, and the clamp member 603 is attached to the screw 604.
The disk 602 is pressed and fixed to the flange portion 63 of the rotary table 61 by tightening. A known method using an information conversion element such as a magnetic head (not shown) mounted on a slider or an optical pickup (not shown) equipped with an objective lens for condensing light by rotating a disk 602 by a motor. An information recording / reproducing apparatus is configured by recording / reproducing on / from the disc 602.

Further, in each of the above-mentioned embodiments, the rotating cylindrical portion 5 is assembled at the time of assembly in a vacuum such as a vacuum chamber.
Alternatively, the bearing portion 10 that rotatably supports the shaft portion including the rotating shaft portion 62.
A predetermined amount of the dynamic pressure lubricant is dropped into the concave portion of the
It is preferable to insert the rotary columnar portion 5 of the rotary disk 6 or the rotary shaft portion 62 of the rotary base 61 into the concave portion. By assembling in a vacuum, bubbles such as air contained in the dynamic pressure lubricant are removed. Furthermore, since the dynamic pressure lubricant does not contain air bubbles such as air, the air bubbles do not expand due to the ambient temperature during operation, so that more stable bearing performance can be exhibited.

As described above, according to the first embodiment, the ball bearing is fitted in the bearing portion, and the retaining member which constitutes a part of the rotor yoke is arranged in the rotating body, and the flange of the bearing sleeve of the bearing is arranged. The ball bearing is arranged between the lower surface of the bearing member and the upper surface of the retaining member, and the distance between the lower surface of the flange portion of the bearing sleeve and the upper surface of the retaining member is [ball diameter of ball bearing + minute Gap] (here, it is desirable that the minute gap is 50 μm or less), so that the rotor moves upward in the direction of the center axis of rotation due to impact caused by falling, collision with another object, or excessive vibration during movement. The amount of deviation (movement) of the information conversion element is limited because the rotating body does not come out from the bearing portion, and the collision displacement amount when the disk and the information conversion element collide is suppressed to a small value. And the members supporting the information conversion element are not fatally damaged.Furthermore, the lower surface of the flange part of the bearing sleeve and the upper surface of the lower flange part of the retaining member contact the ball bearings with the ball of the ball bearing in between. Even if they come into contact with each other, the balls of the ball bearing are interposed between the lower surface of the flange portion of the bearing sleeve and the upper surface of the lower flange portion of the retaining member, so that the rotation of the rotating body is not hindered and smooth rotation is achieved. Can be maintained.

(Second Embodiment) An outline of a motor assembling method of the present invention will be described with reference to FIGS. 1 and 2 in the first embodiment. The assembling method for the embodiment shown in FIG. 5 or FIG. 6 in the above-described first embodiment is also the same as that of the embodiment in FIG. 1, and the description thereof will be omitted here.

As a first step, a bearing portion 10 is formed by attaching a thrust support plate 9 to one end of the bearing sleeve 8 on the side opposite to the flange portion 7 by a method such as press fitting or bonding. A ball bearing serving as a retaining contact member so that a minute gap is formed between a ball of the ball bearing 11 serving as a retaining contact member and the lower surface of the flange portion 7 at a predetermined position on the outer peripheral portion of the sleeve 8. After fitting 11, the dynamic pressure lubricant 201 of a predetermined amount is dropped into the recess of the bearing portion 10, and the annular retainer holding member 14 made of a magnetic material is predetermined so as to be concentric with the rotation center 1. The rotary cylinder 5 of the rotary disk 6 fixed to the position is inserted into the recess of the bearing 10 where the dynamic pressure lubricant 201 is dropped in a vacuum such as a vacuum tank, and the retainer holding member 14 is fixed to the rotary disk. 6 Assembled so as to be rotatable around the bearing portion 10. Here, by using the ball bearing shown in FIG. 4 of the first embodiment, the ball bearing 11 can be easily and accurately positioned with respect to the bearing sleeve 8.

In the second step, a ring-shaped rotary magnet 16 magnetized into a plurality of poles is fixed to the retaining member 15 having a substantially crank-shaped cross section by a method such as press fitting or bonding.
An adhesive is applied to the surface of the retaining member 14 facing the rotary magnet 16 in the portion not covered by the retaining member 15 or the portion not covered by the retaining member 15 to form an upper flange of the retaining member 15. The rotating magnet 16 is brought into contact with the lower surface of the retaining member 14 so that the outer peripheral surface of the portion fits into the inner peripheral surface 17 of the retaining member 14. A magnetic force works between the magnetized rotating magnet 16 and the retaining member 14 made of a magnetic material, and the attraction force causes the rotating magnet 16 and the retaining member 14 to come into close contact with each other via an adhesive. In that state, the adhesive is cured. Since the retaining member 15 is fitted to the retaining member 14 positioned so that the inner peripheral surface thereof is concentric with the rotation center 1, the rotating magnet 16 is easily positioned concentrically with the rotation center 1. Become. Here, the rotating magnet 16 and the retaining member 1
4, the thickness of the retaining member 15 is made smaller than the thickness of the retaining member 14 so that a gap is formed between the upper surface of the retaining member 15 and the lower surface of the rotating disk 6 during contact. It is necessary to have it. Further, as shown in FIG. 7A, the retaining member 15 is easily removed by forming a part of the inner peripheral surface 71 of the retaining member 14 into which the retaining member 15 is fitted. It is guided to the inner peripheral surface of the stop holding member 14. Further, as shown in FIG. 7B, a part 72 of the outer peripheral surface of the upper flange portion of the retaining member 15 may be tapered, and although not shown, the retaining member 14 of the retaining member 14 may be provided. Both a part of the inner peripheral surface and a part of the outer peripheral surface of the upper flange portion of the retaining member 15 may have a tapered shape.

As a third step, a stator 23 in which a coil 22 is wound around each of a plurality of magnetic pole teeth of an iron core 21 and an annular thrust suction plate 24 made of a soft magnetic material.
The base 20 to which is adhered is adhered to the bearing portion 10 that rotatably supports the shaft portion composed of the rotary columnar portion 5 by adhesion or the like.

As described above, according to the second embodiment, the retaining magnet holding member and the rotating magnet integrated with the retaining member are bonded by utilizing the magnetic attraction force of the rotating magnet. The rotating magnet integrated with the retaining member can be easily bonded without damaging the information recording medium layer, and the retaining member is fixed so that the inner peripheral surface is concentric with the rotation center. Since the outer peripheral surface of the retaining member is positioned along the inner peripheral surface of the so as to be guided and fitted, the concentricity with respect to the rotation center of the rotary magnet can be easily ensured.

(Third Embodiment) FIG. 8 is a sectional view showing the outline of the structure of a main part of a motor used in an information recording / reproducing apparatus according to a third embodiment of the present invention. The same reference numerals as those in FIG. 1 are added to the same items as those in FIG. 1 to which the reference numerals are added in the above-described first embodiment. In FIG. 8, the outer peripheral surface of the bearing sleeve 8 is press-fitted or adhered, or the bearing sleeve 8
Is attached to the lower surface of the flange portion 7 of the bearing sleeve 8 while being fitted to the outer peripheral surface of It is fixed to the bearing sleeve 8. As shown in FIG. 9 (a), the retaining ring 81 has a cross section taken along a plane including the axis of the rotation center 1 on the end surface of the bearing sleeve 8 opposite to the lower surface of the flange portion 7. Center of rotation 1
A plurality of trapezoidal protrusions 82 each having a small flat surface perpendicular to the axis and a slanted surface being a part of a substantially spherical shape, as shown in FIG.
As shown in the plan view of the protrusion side in (c), a plurality of protrusions 83 or 8 having a circular shape or an oval shape.
4 is formed, and the retaining contact ring 81 is made of, for example, Teflon (registered trademark), liquid crystal polymer, or PP.
It is made of a material having a low friction coefficient such as S (polyphenylene sulfide). Although FIG. 9 shows an example in which eight protrusions are arranged at substantially equal intervals, the number of protrusions need not be limited to this. The shape of the protrusion 82 is not limited to a spherical base or an ellipsoidal base as long as the tip of the protrusion has a small flat surface. For example, the cross-sectional shape may be trapezoidal, rectangular, or another shape. May be.

The rotary magnet 16 fixed to the retaining member 14 fixed to the lower surface of the rotary disk 6 is
Similar to the first embodiment, the hollow cylinder is made of a magnetic material and has an upper flange portion that extends radially outward at the upper end portion of the hollow cylinder and a lower portion that extends radially inward at the other lower end portion. The retaining member 15 having a crank shape in cross section having a flange portion is fixed to the retaining surface of the retaining member 14 by press-fitting or adhesion so that the retaining member 15 fits in the inner peripheral surface of the retaining member 14.
The upper surface of the lower flange portion of the retaining member 15 should have a minute gap in the direction of the rotation center axis with the small plane of the protrusion 82 of the retaining contact ring 81 facing the upper surface of the lower flange portion of the retaining member 15. Is set to. here,
It is desirable to set this minute gap to 50 μm or less. Other configurations are similar to those of the first embodiment described above, and detailed description thereof will be omitted here.

Needless to say, as in the first embodiment, the axial gap (face-to-face) type brushless motor may be formed, or the individual motor and disk may be formed.

The assembling method is also the same as that of the above-described second embodiment by replacing the ball bearing in the above-mentioned second embodiment with a retaining ring having a plurality of protrusions. Detailed description is omitted here.

As described above, according to the third embodiment, the retaining contact ring made of a material having a low coefficient of friction is fixed to the bearing portion as the retaining contact member to prevent the rotor yoke of the rotor from rotating. By disposing a retaining member that constitutes a part of the retaining member and providing a minute gap between the upper surface of the retaining member and the retaining abutment ring, a drop, The amount of deviation (movement) of the rotating body upward in the direction of the rotation center axis due to impact caused by collision with other objects or excessive vibration during movement will be restricted, and the rotating body will come out of the bearing section. In addition, the collision displacement amount when the disk and the information conversion element collide is suppressed to a small level, without causing fatal damage to the information conversion element and members supporting the information conversion element. Rings have a low coefficient of friction Since it is made of a material, when the retaining ring and the retaining member come into contact with each other, they slide with low friction, so that the rotation of the rotating body is not hindered and smooth rotation is maintained. You can

[0065]

As described above, according to the present invention, the bearing sleeve of the bearing portion that rotatably supports the shaft portion composed of the rotating column portion or the rotating shaft portion has a ball bearing as a retaining contact member or a low friction coefficient. A retaining contact ring made of a material is fixed, and an information recording medium is provided on one surface,
The rotating body, to which the retaining member that forms a part of the rotor yoke is fixed on the other surface, is inserted into the bearing portion where the dynamic pressure lubricant is dropped to rotatably support the rotating body, and the rotating magnet is fixed. The outer peripheral surface of the upper flange portion of the retaining member having a substantially crank-shaped cross section is fitted to the inner peripheral surface of the retaining member, and the rotating magnet is generated by the magnetic attraction between the rotating magnet and the retaining member. Fixed to the retaining member,
In addition, the motor configuration is such that the distance between the upper surface of the lower flange portion of the retaining member and the lower surface of the flange portion of the bearing sleeve or the lower surface of the retaining contact ring is set to a predetermined dimension.

With such a motor configuration,
This will limit the amount of deviation (movement) of the rotating body to the upper side in the direction of the rotation center axis due to impact caused by falling, collision with other objects, or excessive vibration during movement, etc. It does not come out, the amount of collision displacement when the disk and the information conversion element collide is suppressed to a small value, and the information conversion element and members supporting the information conversion element are not fatally damaged. The bottom surface of the flange part of the bearing sleeve and the top surface of the lower flange part of the retaining member contact the ball bearing with the ball in between, or a small flat surface of the tip of the retaining contact ring fixed to the bearing sleeve and the retaining member. Even if the upper surface of the lower flange portion of the member comes into contact, the ball bearing bow is placed between the lower surface of the flange portion of the bearing sleeve and the upper surface of the lower flange portion of the retaining member. Or the retaining abutment ring is made of a material having a low friction coefficient, so that the rotation of the rotating body at the time of abutment is not hindered and smooth rotation can be maintained. It is possible to realize a thin motor and an information recording / reproducing device which are useful for miniaturization.

[Brief description of drawings]

FIG. 1 is a schematic sectional view for explaining a main part of a motor according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged view of a motor main part according to the first embodiment of the present invention.

FIG. 3 is a schematic cross-sectional view for explaining the shape of a ball bearing as a retaining contact member according to the first embodiment of the present invention.

FIG. 4 is a schematic sectional view for explaining another example of the ball bearing according to the first embodiment of the invention.

FIG. 5 is a schematic cross-sectional view for explaining another example of the main part of the motor according to the first embodiment of the present invention.

FIG. 6 is a schematic sectional view for explaining another example of the main part of the motor according to the first embodiment of the present invention.

7A is a schematic sectional view showing the shape of a retaining member according to Embodiment 2 of the present invention, and FIG. 7B is a schematic sectional view showing the shape of a retaining member according to Embodiment 2 of the present invention. Figure

FIG. 8 is a schematic sectional view for explaining a main part of a motor according to a third embodiment of the present invention.

9A is a schematic cross-sectional view showing a shape of a protrusion provided on a retaining ring according to Embodiment 3 of the present invention, and FIG. 9B is a schematic sectional view of Embodiment 3 of the present invention. The schematic plan view (c) showing the shape of the protrusion provided on the retaining abutment ring shows the shape of another example of the protrusion provided on the retaining abutment ring according to the third embodiment of the present invention. Schematic plan view showing

FIG. 10 is a schematic cross-sectional view showing a main part structure of a conventional motor and information recording / reproducing apparatus.

[Explanation of symbols]

1 rotation center 2 main planes 3,601 Information recording medium layer 4 disc section 5 rotating cylinder 6 rotating discs 7,63,103 Flange 8,107 Bearing sleeve 9,108 Thrust support plate 10,110 Bearing part 11 ball bearings 12 Radial bearing 13 Thrust bearing 14, 51, 64 retaining member 15,53 retaining member 16,52,105 rotating magnet 17 Inner surface 18, 54, 65, 104 rotor yoke 19,55,66 rotating body 20,59,67,109 base 21,112 iron core 22,57,113 coils 23,58,114 Stator 24,120 Thrust suction plate 31,41 retainer 32, 42 ball insertion holes 33,43 balls 34,44 Edge edge 56 printed wiring board 61, 101 turntable 62,102 rotating shaft 71 Part of inner surface 72 Part of outer peripheral surface 81 Abutment ring for retaining 82,83,84 Projection 106 rotor 111,201 dynamic pressure lubricant 115 motor 116 plane 117,602 Disc-shaped recording medium (disc) 118,603 Clamping member 119,604 screws d, D diameter H height t thickness α Small size δ, ε distance ΔD protruding amount

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5D109 BA15 BA17 BA20 BA22 BB01                       BB12 BB16 BB18 BB21 BB22                 5H605 AA00 BB05 BB10 BB14 CC04                       DD09 EB03 EB06 EB17 EB38                       GG04                 5H607 AA00 BB01 BB07 BB09 BB14                       BB25 CC01 DD08 DD14 GG01                       GG03 GG09 GG12 JJ04 JJ06                 5H615 AA01 BB01 BB07 BB14 BB17                       PP25 PP28 SS18 SS19

Claims (10)

[Claims] 1. A motor having a stator around which a coil is wound, and a rotary magnet magnetized to have a plurality of poles, which is arranged so as to face the stator. A shaft portion comprising a rotary column portion or a rotary shaft portion is pivotally supported. The retainer has a retaining contact member fixed to a bearing sleeve of the bearing portion, and a rotor having a retaining yoke and a retaining member. The bearing is sandwiched by the retaining contact member. A motor characterized in that a lower surface of a flange portion of a sleeve and an upper surface of a lower flange portion of the retaining member face each other. 2. The motor according to claim 1, wherein the retainer contact member fixed to the bearing sleeve is a ball bearing including a retainer having a ball insertion hole and a ball. 3. The retainer of the ball bearing has a horizontal portion having the ball insertion hole and a vertical portion on at least one side of the horizontal portion, and the ball insertion hole provided in the horizontal portion. Where d is the diameter of the ball of the ball bearing t = the thickness of the horizontal portion of the ball bearing retainer having the ball insertion hole δ = the distance between the uppermost point of the ball of the ball bearing and the lower surface of the flange portion of the bearing sleeve Then, it is in a range satisfying 2 [(t + δ) {D- (t + δ)}] ^1/2 <d <D, and the height H of at least one of the vertical portions of the horizontal portion is the motor according to claim 2, characterized in that the H = δ + D / 2 + (D 2 -d 2) 1/2 + t. 4. The distance between the lower surface of the flange portion of the bearing sleeve and the upper surface of the lower flange portion of the retaining member is a predetermined distance D + α, where D = ball diameter of the ball bearing α = small size The motor according to claim 2, wherein the motor is set to. 5. The small dimension α at the predetermined distance is α <50 μm The motor according to claim 4, wherein 6. The retainer contact member fixed to the bearing sleeve, wherein the retainer contact member is annular and has a plurality of protrusions having a flat surface perpendicular to the center of rotation on one end surface thereof. The motor according to claim 1, wherein the motor is a contact ring. 7. The gap in the rotation axis direction between the small flat surface of the protrusion of the retaining ring and the retaining member facing the protrusion is a predetermined minute dimension. Motor described. 8. The predetermined small dimension β is β <50 μm The motor according to claim 7, wherein 9. A method of assembling a motor having a stator around which a coil is wound and a rotary magnet magnetized with a plurality of poles facing the stator, wherein a shaft portion comprising a rotary columnar portion or a rotary shaft portion is pivotally supported. First fixing a retaining contact member to a bearing sleeve of a bearing portion
And the rotating magnet having the retaining member fixed to the rotating disk rotatably assembled to the bearing portion and the retaining member having a substantially crank-shaped cross section fixed to the retaining member. A second step of adhering by using magnetic force acting between the rotating magnet and the rotating magnet. 10. An information recording / reproducing apparatus equipped with the motor according to claim 1.