JPH0863872A - Disk driving motor - Google Patents

Abstract

PURPOSE: To obtain a motor whose rotational accuracy and reliability are high by a method wherein a laminated inertia is added to a rotor and a thrust bearing is used for a bearing structure in the thrust direction of the motor. CONSTITUTION: A laminated inertia 21 is fixed and bonded to a rotor 1. In addition, a thrust bearing 22 which is received by a plurality of balls 22c sandwiched between a rotating ring 22a and a fixed ring 22b is used for a bearing which receives the load in the thrust direction of the rotor 1. Then, when the rotor 1 is turned, a driving pin 5 is coupled to a disk hub 10, the rotating and driving force of a motor is transmitted to the disk hub 10 via the driving pin 5, the disk hub 10 is turned and driven, and a disk 20 is turned.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor for rotating a recording medium such as a magnetic disk device having a magnetic head for reading and writing magnetic recording signals on the recording medium.

[0002]

[Prior art]

Conventional Example 1 FIG. 29 is a cross-sectional view of essential parts showing a conventional disk drive motor disclosed in, for example, Japanese Patent Laid-Open No. 4-147470.
In the figure, reference numeral 1 denotes a rotor, and this rotor 1 is integrally molded with a rotating shaft 2 to receive a disk hub, a rotor-shaped rotor yoke 4 made of a magnetic metal and integrated with the rotor hub 6, and a rotor hub 6. It is composed of a rotor magnet 3 that generates a magnetic force in the radial direction with respect to the shaft 2 and is fixed to the outer peripheral side of the rotor yoke 4, and a drive pin 5 for engaging with a disk hub. On the other hand, the oil-impregnated metal bearing 9 holding the rotating shaft 2 rotatably is mounted in a housing 11 vertically fitted and fixed to a motor board 7 to which a stator 8 composed of an iron core 8a and a coil 8b is mounted. ing. The stator 8 faces the outer peripheral surface of the rotor magnet 3 with a predetermined gap.

A flat washer-shaped sliding member 12 made of resin or metal is interposed between the rear surface of the rotor hub 6 and the end surface of the oil-impregnated metal bearing 9. This sliding member 1
2, an appropriate thrust load is always applied to the oil-impregnated metal bearing 9 side by the magnetic attraction force of the rotor magnet 3 of the rotor 1. Further, since the end surface of the oil-impregnated metal bearing 9 and the flat surface of the sliding member 12 serve as sliding surfaces, the sliding member 12 is made of carbon tool steel or the like, which is a highly hard material having good wear resistance.

A motor in which the rotor magnet 3 and the stator 8 face each other in the circumferential direction with respect to the rotary shaft 2 of the motor is called a circumferentially opposed motor. Also, the stator 8
It is called an inner rotor type because the rotor 1 is located inside thereof.

Conventional Example 2 FIG. 30 is a cross-sectional view of an essential part showing a conventional disk drive motor disclosed in Japanese Patent Laid-Open No. 5-120789. In FIG. 30, 7 is a motor substrate for supporting the whole motor, Usually, it is a base material such as an iron plate or a silicon steel plate, on which an insulating coating is applied, and a wiring pattern of the circuit is printed and formed on the base material, so that a drive control circuit for driving the motor is not formed. The illustrated electronic components are mounted.

Reference numeral 2 denotes a rotation shaft of the motor, which is a rotation center of the rotor yoke 4 and a rotation center of the disk hub 10.
The rotary shaft 2 is rotatably held in the radial direction by a slide bearing 9 held in a cylindrical housing 11 fixed to a motor substrate 7, and a convex portion formed on the bottom of the rotary shaft 2 has a thrust washer 13. It is supported in the thrust direction by the motor substrate 7 via.

On the upper part of the rotary shaft 2, there is a rotor hub 6
Are fixed by press fitting, etc. This rotor hub 6
The upper surface is provided with a receiving surface for the disk hub 10, and the outer peripheral portion is fitted to the rotor yoke 4. A chucking magnet 14 for attracting and holding the disc hub 10 is fixed on the rotor yoke 4.

Further, the cross-sectional shape of the outer peripheral portion of the rotor yoke 4 is bent into an L shape, and the rotor magnet 3 for generating the driving force of the motor is arranged inside thereof. The rotor magnet 3 is magnetized in the circumferential direction.
On the other hand, a salient pole type iron core 8a is arranged in parallel with the rotor yoke 4 so as to face the inner circumference of the rotor magnet 3, and a coil 8b is wound around each salient pole. Then, by switching the energization and excitation of the coil 8b by a well-known current switching circuit, the electromagnetic force acting between the coil 8b and the rotor magnet 3 is attracted, and repulsion is used to configure the rotor magnet 3, the rotor hub 6, the rotating shaft 2 and the like. Rotated rotor 1 rotates.

An index magnet 15 is fixed to the lower surface of the outer peripheral portion of the rotor yoke 4. Therefore, the index magnet 15 acts on the Hall element 16 which is a magnetic sensor provided on the motor substrate 7, and the index detection is performed by generating the index signal and detecting the predetermined rotation position.

FIG. 31 is a cross-sectional view of the essential parts showing another embodiment of the conventional disk drive motor disclosed in Japanese Patent Laid-Open No. 5-120789 described in Conventional Example 2. In FIG. A sliding member, 9 is an oil-impregnated metal bearing, 2 is a stepped rotary shaft having a two-step outer diameter structure, which is a stepped structure from the rotary shaft 2 of Conventional Example 2.

[0011]

In the disk drive motor of the conventional example 1, since the rotor 1 is located inside the stator 8, the outer diameter of the rotor 1 is small and the inertial load is small. There was a problem that rotation fluctuation was bad. Further, the dispersion of the thrust load is large, and this load is directly applied to the end surface of the oil-impregnated metal bearing 9, resulting in the dispersion of frictional resistance, and finally the life of the oil-impregnated metal bearing 9 is greatly varied. Further, since the sliding member 12 has a large diameter and frictional resistance increases, rotation loss occurs. Also,
Since the sliding member 12 is not fixed to the rotor hub 6, when the rotor 1 is assembled to the oil-impregnated metal bearing 9,
The sliding member 12 was likely to come off and the assemblability was poor. When the rotary shaft 2 is press-fitted and fixed to the rotor yoke 4, it is necessary to assemble while controlling the dimension from one end face of the rotary shaft 2 to the rotor hub 6 because the components are not positioned to each other. It was Further, since it is necessary to use a material having high wear resistance and high hardness, the sliding member 12 often uses a material that easily rusts.

In the disk drive motor of the conventional example 2, the thrust washer 13 and the oil-impregnated metal bearing 9 are mounted on the motor substrate 7, and the rotary shaft 2 is received there. Therefore, when the motor is thinned, There is a problem that the height of the oil-impregnated metal bearing 9 is low by the thickness of the substrate 7 and the thickness of the thrust washer 13, and the bearing length is shortened, which deteriorates the rotational runout accuracy of the motor. Further, the chucking magnet 14 and the index magnet 15 are composed of separate parts from each other, and the productivity is poor.

Further, the stepped structure of the rotary shaft 2 is difficult to process, the precision of the rotary shaft surface and the stepped portion is deteriorated, the rotational runout accuracy of the motor, the inner diameter surface of the oil-impregnated metal bearing 9 and the rotary shaft 2 are deteriorated. There is also a problem in that the surface with poor accuracy comes into contact with the inner diameter surface of the bearing and the life of the bearing is deteriorated.

The present invention has been made in order to solve the above problems, and provides a thin disk drive motor which has high rotational accuracy, low rotational loss, high reliability, and high productivity. The purpose is to

[0015]

[Means for Solving the Problems] Claim 1 according to the present invention
The disk drive motor described is one in which the laminated inertia is fixed to the rotor yoke, and a radial bearing and a thrust ball bearing are used for the disk drive motor of the circumferentially opposed type.

According to a second aspect of the present invention, there is provided a disk drive motor in which a sliding member is interposed between the rear surface of the rotor yoke and the end surface of the oil-impregnated metal bearing, and the load in the thrust direction generated by the magnetic attraction force of the rotor magnet. It is equipped with a washer for adjusting the thrust load that keeps the load constant.

According to a third aspect of the present invention, there is provided a disk drive motor in which the rear surface of the rotor yoke slides on the upper end surface of the oil-impregnated metal bearing, and the sliding surface of the rotor yoke has a small friction coefficient. It has been subjected to a surface treatment with great wear resistance.

According to a fourth aspect of the present invention, in the disk drive motor, the rotary shaft has a stepped shape with a small straight shaft diameter by two parts of a cylindrical straight shaft and a top spherical cap.

According to a fifth aspect of the present invention, in the disk drive motor according to the present invention, the rotary shaft has a stepped shape having a small straight shaft diameter by two parts of a cylindrical straight shaft and a top spherical cap, and a bottom surface of the cap. The end surface of the oil-impregnated metal bearing is the sliding surface of the rotor.

According to a sixth aspect of the present invention, there is provided a disk drive motor in which the rotor rotation shaft is composed of two parts, one of which is a convex portion and the other of which is a concave portion. The shaft and the rotor yoke are fixed to each other.

According to a seventh aspect of the present invention, there is provided a disk drive motor in which a rotor ring magnet of a thrust bearing is fixed to the back surface of a rotor yoke.

According to a eighth aspect of the present invention, there is provided a disk drive motor in which a chucking magnet, an index magnet, and a rotary wheel positioning magnet for a thrust bearing are integrally formed on a rotor yoke.

According to a ninth aspect of the present invention, there is provided a disk drive motor in which the engaging portion of the sliding member provided on the rotor yoke is integrally formed with the chucking magnet and the index magnet in the rotor yoke.

According to a tenth aspect of the present invention, there is provided a disk drive motor according to claim 10, wherein the rotating shaft is formed into a cylindrical shape from the bottom surface, and the inner diameter surface of the rotating shaft is formed by the outer diameter surface of the oil-impregnated metal bearing. It forms a radial bearing.

According to the eleventh aspect of the present invention, there is provided a disk drive motor comprising a straight shaft and a convex cap as a rotary shaft having a cylindrical shape which is hollowed out from the bottom surface.
The thrust bearing is composed of parts, and the cap convex tip end surface is slidably held on the oil-impregnated metal bearing upper surface.

According to a twelfth aspect of the present invention, there is provided a disk drive motor in which a ball is rotatably housed in a hollow cylindrical portion of a rotary shaft, and a thrust load of a rotor is applied between the ball and an upper end portion of an oil-impregnated metal bearing. It is designed to hold.

[0027]

In the disk drive motor according to the first aspect of the present invention, the laminated inertia fixed to the rotor yoke increases the inertial load on the rotor and improves the rotation accuracy of the motor. In addition, the thrust ball bearing reduces the frictional resistance of the rotor and allows smooth and stable rotation.

Further, in the disk drive motor according to the second aspect of the present invention, the sliding member supports the thrust load of the rotor and causes stable rotation. Also, the thrust load adjusting washer manages the thrust load.

In the disk drive motor according to the third aspect of the present invention, the back surface of the rotor yoke is subjected to a surface treatment, and the treated surface has a function equivalent to that of the sliding member.

Further, in the disk drive motor according to the fourth aspect of the present invention, the rotary shaft has a stepped structure with two parts, so that the processing accuracy of the stepped rotary shaft is improved and the rotational accuracy is improved.

Further, in the disk drive motor according to the fifth aspect of the present invention, the stepped rotary shaft composed of two parts and having an improved processing accuracy has the cap bottom surface as a sliding surface, so that a sliding member is provided. Get rid of.

Further, in the disk drive motor according to claim 6 of the present invention, the rotary shaft receives the rotor yoke at the stepped surface of the rotary shaft having the convex portion, and the concave portion of the rotary shaft having the other concave portion fits with the convex portion. The mating rotary shaft is formed and the rotor yoke and the rotary shaft are fixed.

Further, in the disk drive motor according to claim 7 of the present invention, the magnet for locating the rotating wheel of the thrust bearing fixed to the back surface of the rotor yoke is:
When removing the rotor from the motor device, or vice versa,
Since the rotating ring of the thrust bearing does not come off from the rotor due to the magnetic force of the magnet, the assembling workability is improved.

Further, in the disk drive motor according to claim 8 of the present invention, the rotating ring positioning magnet of the thrust bearing fixed to the back surface of the rotor yoke is:
By integrally molding the chucking magnet and index magnet into the rotor yoke, the number of parts and the number of assembly steps are reduced.

Further, in the disk drive motor according to claim 9 of the present invention, the latching portion for restricting the sliding of the sliding member provided on the rotor yoke is formed integrally with the chucking magnet and the index magnet on the rotor yoke. , Reduce the number of parts and assembly man-hours.

According to a tenth aspect of the present invention, in the disk drive motor, the radial bearing is constructed by holding the inner diameter surface of the concave portion at the end of the rotary shaft by the outer diameter surface of the oil-impregnated metal bearing, and the frictional load of the motor. To reduce.

Further, in the disk drive motor according to claim 11 of the present invention, the radial bearing is constituted by holding the inner diameter surface of the rotating shaft by the outer diameter surface of the oil-impregnated metal bearing, and the thrust bearing is constituted by the convex portion of the cap. The tip surface slides on the upper surface of the oil-impregnated metal bearing to reduce the frictional load in the radial and thrust directions of the motor.

According to the twelfth aspect of the present invention, in the disk drive motor, the radial bearing is formed by holding the inner diameter surface of the recess of the rotary shaft end by the outer diameter surface of the oil-impregnated metal bearing, and the thrust bearing is A ball is rotatably housed in a recess at the end of the rotary shaft, and the ball slides on the upper surface of the oil-impregnated metal bearing to reduce the frictional load of the motor in the radial and thrust directions of the motor.

[0039]

【Example】

Example 1. Example 1 Example 1 describes a disk drive motor according to claim 1. Embodiment 1 of the present invention will be described below with reference to the drawings. 1 is a plan view of a motor for rotationally driving a disk according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of a main part of the motor shown in FIG. FIG. 3 is a partially enlarged view of FIG. Further, FIG. 4 is a partial plan view of the chucking portion.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 is a rotor yoke formed by pressing a magnetic material into a cup shape or the like, and reference numeral 2 is a rotary shaft fixed to the rotation center position of the rotor yoke 4 by press fitting or the like and rotating together with the rotor yoke 4. When the rotor yoke 4 and the rotary shaft 2 are fixed, they are supported by a jig or the like so as to keep the distance between the flat surface portion 4a near the inner circumference of the rotor yoke 4 and the tip 2a of the rotary shaft 2 on the curved side constant. While doing.

The material of the rotary shaft 2 is stainless steel,
Alternatively, a free-cutting steel subjected to surface nitriding treatment, a brass subjected to electroless plating, or the like, a material having a hard surface hardness of the rotating shaft 2, or a material treated to be hard is used.

Reference numeral 3 denotes a rotor magnet for generating the driving force of the motor, which is fixed to the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. The rotor magnet 3 is formed in a ring shape so that a magnetic force is generated in the radial direction with respect to the rotating shaft 2, and S, N, S, N,
..., for example, 32 poles are magnetized.

A hub sheet 17 for receiving the disk hub 10 is adhered or fixed to the upper surface of the inner peripheral flat surface portion 4a of the rotor yoke 4 by a double-sided adhesive tape or the like. A chucking magnet 1 for attracting and holding the disk hub 10 is provided on the outer peripheral flat surface portion 4b of the rotor yoke 4.
4 is fixed. The disk 20 is provided near the middle of the inner peripheral flat surface portion 4a and the outer peripheral flat surface portion 4b of the rotor yoke.
A drive pin 5 for transmitting the rotational force of the motor to rotate the disk 20 together with the rotor 1 is mounted on.

Inside the outer circumference of the rotor yoke 4, the back yoke of the rotor magnet 3 of the rotor 1 is also used.
The laminated inertia 21 for increasing the inertial load is fixed. The laminated inertia 21 is formed by stacking a plurality of flat washer-shaped thin plates by crimping, welding, or adhering. It is possible to change the thickness of the rotor yoke 4 and the height of the entire motor depending on the number of layers. There is. Further, by using a material of a high specific gravity material for the laminated inertia 21, it is possible to improve the effect of increasing the inertial load of the rotor 1.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 supporting the motor device by caulking or the like. More precisely, this bearing 9 rotatably holds a load in the radial direction with respect to the rotary shaft 2 of the rotor 1, and for example, the oil-impregnated metal bearing 9
The gap between the inner diameter of the shaft and the outer diameter of the rotary shaft 2 is about several μm. By controlling this gap, it is possible to obtain a motor with good rotational deflection accuracy.

On the outer circumference of the oil-impregnated metal bearing 9, there is arranged a thrust bearing 22 which is supported by the motor substrate 7 like the oil-impregnated metal bearing 9 and receives a load in the thrust direction generated by the magnetic attraction force of the rotor magnet 3. . The thrust bearing 22 includes a rotating wheel 22a that rotates together with the rotor 1.
And the fixed side fixed ring 2 arranged on the upper surface of the motor board 7.
2b, a plurality of (three or more, an odd number is preferable) balls 22c sandwiched between the rotating wheel 22a and the fixed wheel 22b, and a retainer 22d that rotatably supports the balls 22c. The rotary wheel 22a and the fixed wheel 22b are common parts having a flat washer shape and the same thickness. Therefore, the same component sandwiches the ball 22c. The ball 22c is a high hardness steel ball or ceramic ball used in a normal ball bearing. The rotating wheel 22a and the fixed wheel 22b are made of stainless steel.

Stator 8 comprising iron core 8a and coil 8b
Are fixed to the motor board 7. On the iron core 8a, the inner circumference of the iron core 8a is divided into 24 equal parts to form 21 continuous salient poles, and a coil 8b is wound around each salient pole. The rotor magnet 3 faces the inner peripheral surface of the salient pole with a constant gap. Further, as shown in FIG. 3, the height relationship between the rotor magnet 3 and the iron core 8a is the distance Ha from the upper surface of the rotor magnet 3 to the iron core 8a and the distance from the lower surface of the rotor magnet 3 to the lower surface of the iron core 8a. Hb is always Ha> Hb
It is arranged so that. With such a relationship, the rotor magnet 3 is always attracted downward,
The rotor 1 always receives a thrust load in the downward direction. Further, the thrust load due to the magnetic attraction of the rotor magnet 3 is 50 g to 150 g according to the experimental data. The conditions for the above experiment are that the outer diameter of the rotor magnet 3 is 34 mm, and the gap between the rotor magnet 3 and the iron core 8a of the stator 8 is 0.25 mm.

An index magnet 15 is fixed to the inner rear surface of the outer peripheral flat surface portion 4b of the rotor yoke 4. A Hall element 16 as a magnetic sensor is positioned and fixed to the motor board 7 at a position facing the index magnet 15. With this configuration,
The hall element 16 generates an index signal of one pulse per rotation, and the index detection for detecting a predetermined rotation position is performed.

Next, the operation will be described. First, a disc cassette (not shown) accommodating the disc 20 fixed to the disc hub 10 is loaded onto the rotor yoke 4 by a cassette loading mechanism (not shown) on the disc device, and the center hole 10a of the disc hub 10 is loaded. Is fitted into the rotary shaft 2, and the disk hub 10 is attracted and held on the hub sheet by the magnetic force of the chucking magnet 14 fixed on the rotor yoke 4.

At the same time, an electric current for driving a motor (not shown) mounted on the motor board 7 causes a current to flow through the coil 8b of the stator 8, and the current flowing through the stator 8 is sequentially switched and fixed. By switching the excitation of the child 8, an electromagnetic force acts between the coil 8b and the rotor magnet 3, and the rotor magnet 3 rotates due to attraction and repulsion between the coil 8b and the rotor magnet 3, and at the same time, the entire rotor 1 Rotate. Since the laminated inertia 21 is fixed to the rotor 1, the inertial load of the rotor 1 is increased and the rotation accuracy of the motor is improved. In addition, the bearing that receives the load in the thrust direction of the rotor 1
By using the thrust bearing 22 which is received by the plurality of balls 22c sandwiched between the rotating wheel 22a and the fixed wheel 22b, the frictional resistance of the rotor 1 can be reduced and smooth and stable rotation can be achieved.

When the rotor 1 rotates, the drive pin 5 spins with the rotor yoke 4 against the lower surface of the disk hub 10. When the position of the drive pin 5 comes to the engaging hole 10b of the disk hub 10, The drive pin 5 engages with the edge of the hole 10b. That is, the drive pin 5 engages with the disk hub 10, the rotational driving force of the motor is transmitted to the disk hub 10 via the drive pin 5, and the disk hub 10 is rotationally driven, so that the disk 20 rotates.

Example 2. Second Embodiment A second embodiment is a description of another embodiment of the disk drive motor according to claim 1, and FIG.
FIG. 8 is a cross-sectional view of a main part of a motor for rotationally driving a disc according to a second embodiment. Hereinafter, common parts or equivalent parts are designated by common reference numerals, and the description of common parts is omitted.

Reference numeral 3 denotes a rotor magnet for generating the driving force of the motor, which is fixed to the inside of the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. This rotor magnet 3
Is formed in a ring shape, and a magnetic force is generated inward in the radial direction with respect to the rotating shaft 2.
N, S, N ... are magnetized. On the other hand, iron core 8a
The stator 8 including the coil 8b and the
The salient poles of the iron core 8a are arranged on the inner peripheral side of
It is fixed to the motor board 7.

Further, a laminated inertia 21 for increasing the inertial load is fixed to the outer periphery of the rotor yoke 4. The laminated inertia 21 is formed by stacking a plurality of flat washer-shaped thin plates by crimping, welding, or adhering, so that the thickness of the rotor yoke 4 and the height of the entire motor can be changed depending on the number of stacked layers. I have to. Further, the inertial load of the rotor 1 can be adjusted to an optimum value by changing the material.

In the first embodiment, the rotor magnet 3 is fixed to the outer peripheral side surface of the rotor yoke 4, and the stator 8 and the rotor magnet 3 have a constant gap therebetween.
The so-called inner rotor type motor arranged on the outer peripheral side of the rotor yoke 4 and having the laminated inertia 21 fixed to the inner peripheral surface of the rotor yoke 4 is shown. As described above, the rotor magnet 3 is mounted on the inner peripheral surface of the rotor yoke 4. The stator 8 facing the rotor magnet 3 may be a so-called outer rotor type motor disposed inside the rotor magnet 3, and the laminated inertia 21 may be fixed to the outer peripheral side surface of the rotor yoke 4.

Example 3. The third embodiment is a description of another embodiment of the disk drive motor according to claim 1, and FIG.
FIG. 8 is a cross-sectional view of a main part of a motor for rotationally driving a disc according to a third embodiment.

On the inner side of the outer periphery of the rotor yoke 4, a laminated inertia 21 serving as a back yoke of the rotor magnet 3 for increasing the inertial load is fixed. This laminated inertia 21 is made by laminating several flat washer-shaped thin plates by caulking, welding, or adhering.
To change the thickness of the rotor yoke 4 and the height of the entire motor,
We are able to deal with this depending on the number of layers. Also,
A magnetic material is used as the material because it doubles as a back yoke.

The rotor magnet 3 for generating the driving force of the motor is fixed to the inner peripheral side of the laminated inertia 21 by adhesion or the like. This rotor magnet 3 is
It is formed in a ring shape so that a magnetic force is generated inward in the radial direction with respect to the rotating shaft 2, and S, N,
It is magnetized as S, N ... On the other hand, the stator 8 including the iron core 8a and the coil 8b is arranged on the inner peripheral side of the rotor magnet 3 so that the salient poles of the iron core 8a face each other, and is fixed to the motor substrate 7.

In the second embodiment, the rotor magnet 3 is mounted inside the outer circumference of the rotor yoke 4, and the stator 8 facing the rotor magnet 3 is a so-called outer rotor type motor. Although the laminated inertia 21 is fixed to the outer peripheral side surface, as described above, the laminated inertia 21 made of a magnetic material is fixed to the inside of the outer circumference of the rotor yoke 4, and the rotor magnet 3 is mounted inside the laminated inertia 21. The structure may be an outer rotor type motor.

Example 4. The fourth embodiment is an explanation regarding the disk drive motor according to the second aspect, and will be described below with reference to the drawings. FIG. 7 is a sectional view of a main part of a motor for rotationally driving a disk according to a fourth embodiment of the present invention.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. Regarding the load in the radial direction with respect to the rotating shaft 2, the inner diameter surface of the oil-impregnated metal bearing 9 supports the outer diameter surface of the rotating shaft 2. Theoretically, in the gap between the inner diameter surface of the oil-impregnated metal bearing 9 and the outer diameter surface of the rotary shaft 2, a film is formed by the oil contained in the bearing, and the rotary shaft 2 can rotate with low friction. . Further, by controlling the gap to be about several μm, it is possible to obtain a motor with good rotational deflection accuracy.

With respect to the load in the thrust direction with respect to the rotary shaft 2, the thrust load adjusting washer 26 and the flat washer-shaped sliding member 12 made of stainless steel are provided on the back side of the inner peripheral flat surface portion 4a of the rotor yoke 4. Is interposed by the end surface of the oil-impregnated metal bearing 9.
Since the sliding member 12 slides on the end surface of the oil-impregnated metal bearing 9, the surface roughness is, for example, 0.4 μm so that the friction coefficient is as small as possible in order to improve the life or the motor performance.
The mirror surface is finished to m or less, and the flatness is reduced to 10 μm or less.

The thrust load adjusting washer 26 is
It has a thickness of about 0.05 mm and is arranged between the back surface of the rotor yoke 4 and the sliding member 12. The thrust load was determined from the relative height relationship between the rotor magnet 3 and the stator 8, and this relationship was an experimental value of about 400 g / mm. Therefore, if the thrust load adjusting washer 26 having a thickness of 0.05 mm is used to adjust the target thrust load value, the adjustment can be performed within the range of 20 g. The conditions for the above experiment are that the outer diameter of the rotor magnet 3 is 34 mm, and the gap between the rotor magnet 3 and the iron core 8a of the stator 8 is 0.25 mm.

Further, when adjusting to the target thrust load, the dimensions and the dimensional tolerances of the related parts are determined so as to be achieved by adding at least one thrust washer 26 for adjusting the thrust load. are doing. Therefore, the target thrust load is not exceeded even when the cumulative tolerance of each component is maximized.

Example 5. The fifth embodiment is an explanation of another embodiment of the disk drive motor according to the second aspect of the present invention.
FIG. 8 is a cross-sectional view of a main part of a motor for rotationally driving a disc according to a third embodiment.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. Regarding the load in the radial direction with respect to the rotating shaft 2, the inner diameter surface of the oil-impregnated metal bearing 9 supports the outer diameter surface of the rotating shaft 2. Regarding the load in the thrust direction with respect to the rotary shaft 2, a structure is adopted in which a plurality of thrust load adjusting washers 26 are interposed between the back surface of the inner peripheral flat surface portion 4a of the rotor yoke 4 and the end surface of the oil-impregnated metal bearing 9. It has become.

The thrust load adjusting washer 26 is
It also serves as the sliding member 12 shown in the fourth embodiment. Therefore, in order to reduce the friction coefficient as much as possible to improve the life or motor performance, the surface roughness should be 0.4 μm, for example.
The mirror surface is finished to m or less, and the flatness is reduced to 10 μm or less. Further, the hardness of the material used is the same as that of the sliding member 12.

The rotary shaft 2 is fixed to the rotational center position of the rotor yoke 4 by press fitting or the like. The thrust load adjusting washer 26 is fixed by press fitting or the like to the outer peripheral side of the press fitting end portion 4c of the rotor yoke 4 into which the rotary shaft 2 is press fitted. This thrust load adjustment washer 26
When fixing, the outer diameter of the press-fitting end 4c and the inner diameter of the thrust load adjusting washer 26 are strictly controlled so as not to impair the flatness of the thrust load adjusting washer 26.

In the fourth embodiment, the thrust load adjusting washer 26 and the sliding member 12 are mounted between the rear surface of the rotor yoke 4 and the end surface of the oil-impregnated metal bearing 9.
As described above, the thrust load adjusting washer 26 has the same hardness and surface roughness as the sliding member 12, and the thrust load adjusting washer is provided between the back surface of the rotor yoke 4 and the end surface of the oil-impregnated metal bearing 9. As a result of mounting a plurality of 26, even if the sliding member is eliminated, the same effect as in the fourth embodiment can be obtained.

Example 6. The sixth embodiment is an explanation regarding the disk drive motor according to the third aspect, and will be explained below with reference to the drawings. FIG. 9 is a sectional view of a main part of a motor for rotationally driving a disk according to a sixth embodiment of the present invention.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. Regarding the load in the radial direction with respect to the rotating shaft 2, the inner diameter surface of the oil-impregnated metal bearing 9 supports the outer diameter surface of the rotating shaft 2. This structure is exactly the same as that of the fourth embodiment.

With respect to the load in the thrust direction with respect to the rotary shaft 2, the back surface of the inner peripheral flat surface portion 4a of the rotor yoke 4 serves as a sliding surface with respect to the end surface of the oil-impregnated metal bearing 9, and the structure is received by this surface. ing. The rear surface of the inner peripheral flat surface portion 4a of the rotor yoke 4 is subjected to surface treatment such as surface nitriding or electroless plating. By this surface treatment, a thin hardened layer is formed on the back surface of the rotor yoke 4. Further, after the above surface treatment, the surface-hardened surface is polished with a barrel or the like to finish the surface of the originally rough magnetic material surface to finish the roughened surface into a substantially mirror surface state. There is. Sliding by the back surface of the rotor yoke 4 and the end surface of the oil-impregnated metal bearing 9 thus finished has the same effect as when a sliding member made of metal or the like having a low friction coefficient is used.

Example 7. Example 7 is an explanation regarding a disk drive motor according to claim 4, and will be described below with reference to the drawings. FIG. 10 is a sectional view of the essential parts of a motor for rotationally driving a disk according to the seventh embodiment of the present invention.

Reference numeral 2 is a rotary shaft composed of two parts, a straight shaft 2b having a spherical end at one end and a cap 2c formed in a cylindrical shape. The straight shaft 2b and the cap 2c are fixed by press fitting or the like, and the spherical shape of the upper end portion 2a of the rotary shaft 2 is formed by fitting the straight shaft 2b and the cap 2c. Further, the rotor yoke 4 is fixed to the outer periphery of the cap 2c by press fitting or the like, and the rotary shaft 2 composed of the above two parts rotates together with the rotor yoke 4. Further, the press-fitting end portion 4c of the rotor yoke 4 is designed so as not to be indented below the end surface of the cap 2c opposite to the spherical surface. The straight shaft 2b and the cap 2 are easier to machine and polish than the stepped rotary shaft in which these two parts are integrated, and are finished with good dimensional accuracy.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. In the radial direction with respect to the rotary shaft 2, the oil-impregnated metal bearing 9 has an inner diameter surface that holds the outer diameter surface of the straight shaft 2b of the rotary shaft 2. The thrust direction of the rotary shaft 2 is received by the end surface of the oil-impregnated metal bearing 9 through the sliding member 12 on the end surface of the cap 2c. in this way,
Since the rotating shaft 2 is stepped to reduce the diameter of the sliding member, the rotation loss can be reduced. Further, since the rotating shaft 2 has a stepped structure, the driving current value of the motor, which is an index of the rotation loss, is an experimental value when the diameter of the straight shaft 2b is reduced by about 60% as compared with the case where the stepping is not stepped. It was reduced by about 25%.

The lower end of the rotary shaft 2 extends to a position aligned with the lower surface of the motor board 7. This is because the length of the contact portion of the oil-impregnated metal bearing 9 that receives the radial direction with the rotating shaft 2, that is, the so-called bearing height, is made as long as possible. By increasing the bearing height, the rotational runout accuracy is improved. A small and stable motor characteristic can be obtained. Further, a major factor that affects the rotational run-out accuracy is the above-described clearance between the bearing height, the outer diameter of the rotary shaft 2 and the inner diameter of the oil-impregnated metal bearing 9, and the bearing height is long and the clearance is small. The better the rotational runout accuracy is. However, the above-mentioned clearance is originally only about several μm even at room temperature, and the bearing height is the most important factor.

Therefore, this structure is very effective for obtaining a thin disk drive motor with low rotational loss and good rotational runout accuracy.

Example 8. Example 8 is an explanation of another example of the disk drive motor according to claim 4, and FIG.
FIG. 16 is a cross-sectional view of a main part of a motor for rotationally driving a disc according to an eighth embodiment.

2 is a straight shaft 2 whose both ends are flat.
b and 2 of the cap 2c having a spherical shape at one end and a concave shape at the other end
It is a rotating shaft composed of parts. Straight shaft 2
b and the cap 2c are fixed to each other by press fitting or the like to form a stepped rotary shaft 2. Further, the rotor yoke 4 is fixed to the outer periphery of the cap 2c by press fitting or the like, and the rotary shaft 2 composed of the above two parts rotates together with the rotor yoke 4. Further, the press-fitting end portion 4c of the rotor yoke 4 is designed so as not to be indented below the end surface of the cap 2c opposite to the spherical surface. The straight shaft 2b and the cap 2c are more easily machined and polished than the stepped rotary shaft in which these two parts are integrated, and have good dimensional accuracy.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. Regarding the load in the radial direction with respect to the rotary shaft 2, the inner diameter surface of the oil-impregnated metal bearing 9 holds the outer diameter surface of the straight shaft 2b of the rotary shaft 2, and with respect to the load in the thrust direction with respect to the rotary shaft 2, the cap is used. The end surface of 2c is received by the end surface of the oil-impregnated metal bearing 9 via the sliding member 12.

In the seventh embodiment, the straight shaft 2b having one spherical end and the cylindrical cap 2c are fixed by press fitting or the like to form the rotary shaft 2. Even if the rotating shaft 2 is composed of the shaft 2b and the cap 2c having a spherical surface on one side and a concave shape on the other side, the same effect as that of the seventh embodiment can be obtained. .

Example 9. The ninth embodiment is an explanation of the disk drive motor according to the fifth aspect of the present invention, which will be described below with reference to the drawings. FIG. 12 is a cross-sectional view of essential parts of a motor for rotationally driving a disk according to the ninth embodiment of the present invention.

Reference numeral 2 denotes a rotary shaft composed of two parts, a straight shaft 2b having a spherical end at one end and a cap 2c formed in a cylindrical shape. The straight shaft 2b and the cap 2c are fixed by press fitting or the like, and the spherical shape of the upper end portion 2a of the rotary shaft 2 is formed by fitting the straight shaft 2b and the cap 2c. Further, the rotor yoke 4 is fixed to the outer periphery of the cap 2c by press fitting or the like, and the rotary shaft 2 composed of the above two parts rotates together with the rotor yoke 4.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. In the radial direction with respect to the rotary shaft 2, the oil-impregnated metal bearing 9 has an inner diameter surface that holds the outer diameter surface of the straight shaft 2b of the rotary shaft 2. Further, in the thrust direction with respect to the rotary shaft 2, the end surface of the oil-impregnated metal bearing 9 receives the bottom surface of the cap 2c. The cap 2c is made of stainless steel and has a high hardness, and the bottom surface of the cap 2c is
A low coefficient of friction is achieved by finishing the mirror surface by polishing the barrel. The outer diameter of the end surface of the oil-impregnated metal bearing 9 is always smaller than the outer diameter of the cap 2c.

Example 10. The tenth embodiment is an explanation regarding the disk drive motor according to the sixth aspect, and will be explained below with reference to the drawings. FIG. 13 is a cross-sectional view of essential parts of a motor for rotationally driving a disk according to the tenth embodiment of the present invention.

Reference numeral 2 is a rotary shaft formed by two parts, a straight shaft 2b having a concave shape at one end and a cap 2c having a convex shape. Reference numeral 3 denotes a rotor magnet for generating a driving force of the motor, which is fixed to the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. Also, the rotor yoke 4
The inner side of the outer circumference of the laminated magnet 2 also serves as the back yoke of the rotor magnet 3 and serves to increase the inertial load.
1 is fixed. A hole is formed in the center of rotation of the rotor yoke 4 so as to fit with the diameter of the convex portion of the cap 2c.

The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like, and rotatably holds a load in the radial direction with respect to the rotary shaft 2. . Further, on the outer circumference of the oil-impregnated metal bearing 9, there is arranged a thrust bearing 22 which is supported by the motor substrate 7 and which receives a load in the thrust direction with respect to the rotary shaft 2, similarly to the oil-impregnated metal bearing 9.

Rotor yoke 4 and rotating shaft 2 consisting of two parts
In assembling with, first, the convex portion of the cap 2c is fitted into the hole at the center of rotation of the rotor yoke 4. Then cap 2
The rotor yoke 4 and the rotary shaft 2 are integrated by press-fitting and fixing the outer diameter of the convex portion of c and the inner diameter of the concave portion of the straight shaft 2b. With such a structure, when the rotary shaft 2 and the rotor yoke 4 are fixed, the spherical tip 2a of the rotary shaft 2 to the upper surface of the inner peripheral flat surface portion 4a of the rotor yoke 4, or the other end of the rotary shaft 2 to the inner peripheral surface of the rotor yoke 4. It is not necessary to assemble the flat surface portion 4a while controlling the dimension up to the back surface portion with a jig or the like.

Example 11. The eleventh embodiment is a description of another embodiment of the disk drive motor according to the sixth aspect, and FIG. 14 is a cross-sectional view of essential parts of a motor for rotationally driving the disk according to the eleventh embodiment.

Reference numeral 2 denotes a rotary shaft formed of two parts, a straight shaft 2b having a convex shape at one end and a cap 2c having a concave shape. Reference numeral 4 is a rotor yoke, and the straight shaft 2b is provided at the center of rotation of the rotor yoke 4.
There is a hole that fits with the diameter of the convex part. Rotating shaft 2
The oil-impregnated metal bearing 9 rotatably supporting is fixed to the motor substrate 7 by caulking or the like. Regarding the load in the radial direction with respect to the rotating shaft 2, the oil-impregnated metal bearing 9
The inner diameter surface of the structure supports the outer diameter surface of the straight shaft 2b. With respect to the load in the thrust direction with respect to the rotating shaft 2, the thrust load adjusting washer 26 and the flat washer-shaped sliding member 12 made of stainless steel are interposed on the back side of the inner peripheral flat surface portion 4a of the rotor yoke 4. The end surface of the oil-impregnated metal bearing 9 receives the oil.

Rotor yoke 4 and rotating shaft 2 consisting of two parts
In assembling with, first, the convex portion of the straight shaft 2b is fitted into the hole of the rotation center of the rotor yoke 4. afterwards,
The rotor yoke 4 and the rotary shaft 2 are integrated by press-fitting and fixing the outer diameter of the projection of the straight shaft 2b and the inner diameter of the recess of the cap 2c. With such a structure, when the rotary shaft 2 and the rotor yoke 4 are fixed, the spherical tip 2a of the rotary shaft 2 to the upper surface of the inner peripheral flat surface portion 4a of the rotor yoke 4, or the other end of the rotary shaft 2 to the inner peripheral surface of the rotor yoke 4. It is not necessary to assemble the flat surface portion 4a while controlling the dimension up to the back surface portion with a jig or the like.

In the tenth embodiment, the rotary shaft 2 is formed by the straight shaft 2b having a concave shape at one end and the cap 2c having a convex shape. However, as in the eleventh embodiment, the rotary shaft 2 has a convex shape at one end. Partial straight shaft 2
The rotating shaft 2 may be formed by b and the concave cap 2c, and the same effect as that of the tenth embodiment can be obtained. In the tenth embodiment described above, the structure for holding the rotor 1 is composed of the oil-impregnated metal bearing 9 and the thrust bearing 22, which is the same as the oil-impregnated metal bearing 9 as in the fourth embodiment. It may be composed of the sliding member 12.

Example 12. The twelfth embodiment is a description of another embodiment of the disk drive motor according to the sixth aspect, and FIGS. 15 and 16 are sectional views of the essential parts of the motor for rotationally driving the disk according to the twelfth embodiment.

In FIG. 14, 2 is a straight shaft 2b having a concave shape at one end and a convex cap 2c.
It is a rotating shaft formed from two parts. Reference numeral 4 is a rotor yoke, and a hole is formed in the center of rotation of the rotor yoke 4 by drawing a magnetic metal sheet. Then, the rotation center hole of the rotor yoke 4 is press-fitted into the convex portion of the cap 2c, and then the straight shaft 2b is attached to the integrated cap 2c and rotor yoke 4.
At this time, the rotor yoke 4 is press-fitted by the outer diameter portion of the press-fitting end portion 4c and the inner diameter of the recess of the straight shaft 2b.

In FIG. 15, 2 is a straight shaft 2b having a convex shape at one end and a cap 2c having a concave shape.
It is a rotating shaft formed from two parts. Reference numeral 4 is a rotor yoke, and a hole is formed in the center of rotation of the rotor yoke 4 by drawing a magnetic metal sheet. Then, the rotation center hole of the rotor yoke 4 is press-fitted into the convex portion of the straight shaft 2b, and then the cap 2c is attached to the straight shaft 2b and the rotor yoke 4 which are integrated. At this time, the rotor yoke 4 is press-fitted by the outer diameter portion of the press-fitting end portion 4c and the inner diameter of the concave portion of the cap 2c.

As described above, in the tenth embodiment, the center of rotation of the rotor yoke 4 is a hole, and the hole and the convex portion of the cap 2c are fitted to each other, and then the concave portion of the straight shaft 2b is press-fitted and fixed. However, the center of rotation of the rotor yoke 4 may be a hole formed by drawing a sheet metal, and the convex portion of the cap 2c or the straight shaft 2b is press-fitted into the drawn hole of the rotor yoke 4, and then the straight shaft 2b or the cap 2c. Even if the structure is such that the press-fitted outer diameter portion of the drawing process is press-fitted into the concave portion, the same effect as that of the tenth embodiment is achieved.

Example 13 The thirteenth embodiment is a description of the disk drive motor according to the seventh aspect, and will be described below with reference to the drawings. FIG. 17 is a cross-sectional view of essential parts of a motor for rotationally driving a disk according to Embodiment 13 of the present invention.

Similar to the first embodiment, 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 denotes a rotor yoke formed by pressing a magnetic material into a cup shape.
Is a rotating shaft fixed to the rotation center position of the rotor yoke 4 by press fitting or the like and rotating together with the rotor yoke 4. The rotor 1 is rotatably held by an oil-impregnated metal bearing 9 and a thrust bearing 22 supported by a motor substrate 7. Then, the inner peripheral flat surface portion 4a of the rotor yoke 4
A sheet-shaped plastic magnet 27 is arranged between the rear surface of the thrust bearing 22 and the stainless rotary wheel 22a of the thrust bearing 22, and the plastic magnet 27 is
It is adhered to the rotor yoke 4 or fixed with a double-sided adhesive tape or the like.

The procedure for assembling the above-mentioned parts is as follows.
Is fixed to the motor substrate 7 by caulking or the like, and then the fixed ring 22b of the thrust bearing 22 is mounted on the motor substrate 7 on the outer periphery of the oil-impregnated metal bearing 9. And
Ball 22c and retainer 2 integrated during assembly
2d is mounted on the fixed ring 22b. In addition, the rotor 1 having the plastic magnet 27, the rotary shaft 2 and the like connected thereto is provided with the rotary ring 22a of the thrust bearing 22.
It is joined to the surface of the plastic magnet 27 by the attractive force of the plastic magnet 27, and in that state the rotary shaft 2 of the rotor 1 is set in the inner diameter of the oil-impregnated metal bearing 9 for assembly. At this time, since the rotating wheel 22a is integrated with the rotor 1, the assembling workability is improved.

Example 14. The fourteenth embodiment is a description of another embodiment of the disk drive motor according to the seventh aspect, and FIG. 18 is a cross-sectional view of essential parts of a motor for rotationally driving the disk according to the fourteenth embodiment.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 is a rotor yoke formed by pressing a magnetic material into a cup shape or the like, and reference numeral 2 is a rotary shaft fixed to the rotation center position of the rotor yoke 4 by press fitting or the like and rotating together with the rotor yoke 4. Rotating shaft 2 of rotor 1
On the other hand, the radial load has a structure in which the inner diameter surface of the oil-impregnated metal bearing 9 fixed to the motor substrate 7 by caulking or the like supports the outer diameter surface of the rotating shaft 2. The load in the thrust direction with respect to the rotating shaft 2 of the rotor 1 is applied to the end surface of the oil-impregnated metal bearing 9 by interposing a flat washer-shaped sliding member 12 on the back side of the inner peripheral flat surface portion 4a of the rotor yoke 4. It is structured to receive. A sheet-shaped plastic magnet 27 is arranged between the back surface of the inner peripheral flat surface portion 4 a of the rotor yoke 4 and the sliding member 12, and the plastic magnet 27 is bonded to the rotor yoke 4.
Alternatively, it is fixed with double-sided adhesive tape or the like.

The procedure for assembling the above-mentioned parts is as follows.
Are fixed to the motor board 7 by caulking or the like. afterwards,
The sliding member 12 is joined to the surface of the plastic magnet 27 by the attracting force of the plastic magnet 27 in the rotor 1 which is connected to the plastic magnet 27 and the rotating shaft 2 and the like. The rotary shaft 2 of the rotor 1 is assembled by fitting it into the inner diameter of the oil-impregnated metal bearing 9. At this time, since the sliding member 12 is integrated with the rotor 1, the assembling workability is improved.

In the thirteenth embodiment, the bearing structure is composed of the oil-impregnated metal bearing 9 and the thrust bearing 22 similar to those of the first embodiment.
Plastic magnet 27 fixed to rotor yoke 4
Shows the structure for attracting the rotating wheel 22a of the thrust bearing 22, but the bearing structure may be composed of the oil-impregnated metal bearing 9 and the sliding member 12 as in the fourteenth embodiment. Since the sliding member 12 is attracted to the plastic magnet 27, the assembly workability is improved as in the thirteenth embodiment.

Example 15. The fifteenth embodiment relates to the disk drive motor according to the eighth aspect of the invention, and will be described below with reference to the drawings. FIG. 19 is a plan view of a rotor portion of a motor for rotationally driving a disk according to the fifteenth embodiment of the present invention. 20 is a cross-sectional view of a main part of the motor shown in FIG.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 is a rotor yoke formed by pressing a magnetic material into a cup shape or the like, and reference numeral 2 is a rotary shaft fixed to the rotation center position of the rotor yoke 4 by press fitting or the like and rotating together with the rotor yoke 4. Reference numeral 3 denotes a rotor magnet for generating a driving force of the motor, which is fixed to the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. The rotor magnet 3 is provided inside the outer circumference of the rotor yoke 4.
The laminated inertia 21 for increasing the inertial load, which also serves as the back yoke, is fixed. The rotor 1 is rotatably held by an oil-impregnated metal bearing 9 and a thrust bearing 22 supported by a motor substrate 7.

The outer peripheral flat surface portion 4b of the rotor yoke 4 is
Is provided with a chucking magnet 14 for attracting and holding the disk hub, and an index magnet 15 is provided on the outer peripheral rear surface of the rotor yoke 4 facing the Hall element 16 which is a magnetic sensor positioned and fixed to the motor substrate 7. A plastic magnet 27 for arranging and holding the rotary wheel 22a of the thrust bearing 22 on the rotor yoke 4 during assembly work is arranged on the back surface of the inner peripheral flat surface portion 4a of the rotor yoke 4. The three types of magnets are integrated by being outsert-molded on the rotor yoke 4 made of a magnetic material. At the time of integral outsert molding, there is no magnetic force in each magnet, and after molding, the magnets are magnetized so as to generate respective required magnetic forces.
In the step of performing this magnetization, there is a method of sequentially magnetizing each magnet, and a method of simultaneously magnetizing three locations.

Example 16. The sixteenth embodiment is an explanation regarding the disk drive motor according to the ninth aspect, and will be described below with reference to the drawings. FIG. 21 is a plan view of a rotor of a motor for rotationally driving a disk according to the sixteenth embodiment of the present invention. 22 is a cross-sectional view of a main part of the motor shown in FIG. FIG. 23 is a rear view of the rotor.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 is a rotor yoke formed by pressing a magnetic material into a cup shape or the like, and reference numeral 2 is a rotary shaft fixed to the rotation center position of the rotor yoke 4 by press fitting or the like and rotating together with the rotor yoke 4. Reference numeral 3 denotes a rotor magnet for generating a driving force of the motor, which is fixed to the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. The rotor magnet 3 is provided inside the outer circumference of the rotor yoke 4.
The laminated inertia 21 for increasing the inertial load, which also serves as the back yoke, is fixed. The oil-impregnated metal bearing 9 that rotatably holds the rotating shaft 2 is fixed to the motor substrate 7 by caulking or the like. A load in the radial direction with respect to the rotary shaft 2 of the rotor 1 is held by the inner diameter surface of the oil-impregnated metal bearing 9, and a load in the thrust direction with respect to the rotary shaft 2 is retained through the sliding member 12. It is held by the end surface of the bearing 9.

A protrusion 12a is provided on the outer periphery of the sliding member 12 so that the sliding member 12 and the rotor yoke 4 always rotate simultaneously.
However, a locking portion 30 is provided on the back surface of the rotor yoke 4 so that the protrusion 12a is caught by the rotor yoke 4. The locking portion 30 together with the chucking magnet 14 for attracting and holding the disk hub and the Hall element 16 together with the two magnets of the index magnet 15 for generating an index signal,
The rotor yoke 4 made of a magnetic material is integrally formed by outsert molding. Further, during integral outsert molding, each magnet has no magnetic force, and after molding, the magnets are magnetized so as to generate respective required magnetic forces. In the step of performing this magnetization, there is a method of sequentially magnetizing each magnet or a method of simultaneously magnetizing two locations.

Example 17 Example 17 is a description of another example of the disk drive motor according to claim 9, FIG. 24 is a rear view of a rotor portion of a motor for rotationally driving a disk according to Example 17, and FIG. FIG.

Reference numeral 2 denotes a rotary shaft composed of two parts, a straight shaft 2b having a spherical end at one end and a cap 2c formed in a cylindrical shape. The straight shaft 2b and the cap 2c are fixed by press fitting or the like, and the spherical shape of the upper end portion 2a of the rotary shaft 2 is formed by fitting the straight shaft 2b and the cap 2c. The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like. In the radial direction with respect to the rotary shaft 2, the oil-impregnated metal bearing 9 has an inner diameter surface that holds the outer diameter surface of the straight shaft 2b of the rotary shaft 2. Further, in the thrust direction with respect to the rotary shaft 2, the sliding member 12 is provided on the bottom surface of the cap 2c.
The end surface of the oil-impregnated metal bearing 9 is configured to be received via.

A projection 12a is provided on the outer periphery of the sliding member 12 so that the sliding member 12 and the rotor yoke 4 always rotate simultaneously.
However, a locking portion 30 is provided on the back surface of the rotor yoke 4 so that the protrusion 12a is caught by the rotor yoke 4. The locking portion 30 together with the chucking magnet 14 for attracting and holding the disk hub and the Hall element 16 together with the two magnets of the index magnet 15 for generating an index signal,
The rotor yoke 4 made of a magnetic material is integrally formed by outsert molding. Further, during integral outsert molding, each magnet has no magnetic force, and after molding, the magnets are magnetized so as to generate respective required magnetic forces. In the step of performing this magnetization, there is a method of sequentially magnetizing each magnet or a method of simultaneously magnetizing two locations.

In the sixteenth embodiment, the end surface of the oil-impregnated metal bearing 9 that receives the sliding member 12 is the back surface of the inner peripheral flat surface portion 4a of the rotor yoke 4, but as described above, the end surface is Straight shaft 2b and cap 2c 2
It may be the bottom surface of the cap 2c of the rotary shaft 2 made of parts, and a locking portion for restricting the sliding movement of the sliding member 12 is provided in the rotor yoke 4 by such a structure, and the chucking magnet 14 and the index are provided. Even in the structure in which the magnet 15 is integrated with the outsert, the structure of the above-mentioned Example 16 is used.
Has the same effect as.

Example 18. The eighteenth embodiment is an explanation regarding the disk drive motor according to the tenth aspect, and will be described below with reference to the drawings. FIG. 26 is a sectional view of the essential parts of a motor for rotationally driving a disk according to the eighteenth embodiment of the present invention.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 denotes a rotor yoke formed by pressing a magnetic material into a cup shape. Reference numeral 2 denotes a rotating shaft having a cylindrical shape having a flat bottom inside from one end, and is fixed to the rotation center position of the rotor yoke 4 by press fitting or the like. Further, the inner diameter surface and the bottom surface of the inner diameter portion of the rotating shaft 2 are finished with a surface roughness of 1 μm or less.
Reference numeral 3 denotes a rotor magnet for generating a driving force of the motor, which is fixed to the outer peripheral side surface of the rotor yoke 4 by adhesion or the like. Further, a laminated inertia 21 for increasing the inertial load, which also serves as a back yoke of the rotor magnet 3, is fixed to the inner side of the outer periphery of the rotor yoke 4.

The oil-impregnated metal bearing 9 fitted into the hollowed portion of the rotary shaft 2 and rotatably supporting the rotary shaft 2 rotatably supports the rotor 1 on the motor substrate 7 by caulking or the like. It is fixed with sufficient force. The portion of the oil-impregnated metal bearing 9 that supports the rotary shaft 2 has a cylindrical shape, and the outer diameter surface of the oil-impregnated metal bearing 9 holds the rotary shaft 2 of the rotor 1 rotatably in the radial direction. ,
The upper surface of the oil-impregnated metal bearing 9 holds the thrust direction with respect to the rotary shaft 2. The outer diameter surface and the upper surface of the oil-impregnated metal bearing 9 are end-face processed so that the rotor 1 can rotate smoothly.

Example 19 The nineteenth embodiment is an explanation of the disk drive motor according to the eleventh aspect, and will be described below with reference to the drawings. FIG. 27 is a cross-sectional view of essential parts of a motor for rotationally driving a disk according to the nineteenth embodiment of the present invention.

Reference numeral 1 is a rotor which indicates the entire rotating portion of the motor. The rotating shaft 2 has a cap 2 having a convex bottom surface.
c and the cylindrical straight shaft 2b are fixed by press fitting or the like, and are fixed to the cup-shaped rotor yoke 4. When the rotating shaft 2 is fixed to the rotor yoke 4, the curved tip portion 2 of the cap 2c is used.
It is performed using a jig or the like so as to keep the distance between a and the inner peripheral flat surface portion 4a of the rotor yoke 4 constant. The oil-impregnated metal bearing 9 rotatably supporting the rotary shaft 2 is fixed to the motor substrate 7 by caulking or the like with a force sufficient to rotatably support the rotor 1. In the radial direction with respect to the rotary shaft 2, the outer diameter surface of the oil-impregnated metal bearing 9 receives the inner diameter surface of the straight shaft 2b of the rotary shaft 2 so as to be held rotatably. Further, in the thrust direction with respect to the rotating shaft 2, the upper surface of the oil-impregnated metal bearing 9 receives the bottom surface of the convex portion of the cap 2c of the rotating shaft 2 so as to be rotatably held. The bottom surface of the convex portion of the cap 2c can improve the processing accuracy and can manage the surface roughness more strictly than the bottom surface of the concave portion of the integrated rotary shaft 2 shown in the eighteenth embodiment. It can rotate smoothly.

Example 20. Example 20 is a description of a disk drive motor according to claim 12, which will be described below with reference to the drawings. FIG. 28 is a cross-sectional view of essential parts of a motor for rotationally driving a disk according to Embodiment 20 of the present invention.

Reference numeral 1 is a rotor that indicates the entire rotating portion of the motor. Reference numeral 4 denotes a rotor yoke formed by pressing a magnetic material into a cup shape. The rotary shaft 2 has a cylindrical hollow shape from one end face, and the tip of the hollow portion is conically closed. The central axis of the conical taper portion is processed so as to coincide with the center of the rotary shaft 2. The rotating shaft 2 is fixed to the center of rotation of the rotor yoke 4 by press fitting or the like. Then, when the rotary shaft 2 is fixed to the rotor yoke 4, a jig or the like is used so as to keep the distance between the curved distal end portion 2a of the rotary shaft 2 and the inner peripheral flat surface portion 4a of the rotor yoke 4 constant. .
Further, with respect to the load in the radial direction with respect to the rotary shaft 2, the outer diameter surface of the oil-impregnated metal bearing 9 receives the straight inner diameter surface of the cylindrical portion of the rotary shaft 2 to rotatably hold the load. Regarding the load in the thrust direction with respect to the rotating shaft 2, the thin plate-shaped thrust washer 1 made of metal or resin having a low friction coefficient is provided on the upper surface of the oil-impregnated metal bearing 9.
3 and the ball 31 on the thrust washer 13 receive the conical taper portion of the rotary shaft 2 to hold it rotatably. As described above, by forming the support structure in the thrust direction into the tapered portion of the ball 31 and the rotary shaft 2 around the rotary shaft, the friction load is reduced, the rotation loss is small, and the rotor 1 can rotate smoothly.

[0121]

As described above, according to the present invention as set forth in claim 1, the laminated inertia is added to the rotor and the thrust bearing is used in the thrust direction bearing structure of the circumferentially opposed disk drive motor. A disk drive motor with high rotation accuracy and high reliability can be obtained.

According to the invention of claim 2,
Since it has a structure with a washer for adjusting the thrust load,
The effect of improving the reliability of the device can be obtained.

According to the invention of claim 3,
Since the rear surface of the rotor yoke is surface-treated to eliminate the sliding member, the device can be made inexpensive and the assembly workability can be obtained.

According to the invention of claim 4,
Since the rotary shaft has a stepped structure with two parts, there is an effect that a device with good processing accuracy and rotation accuracy can be obtained.

According to the present invention of claim 5,
Since the bottom surface of the cap of the rotary shaft is configured to slide on the oil-impregnated metal bearing, there is an effect that the device can be inexpensive and the device can be easily assembled.

Further, according to the invention of claim 6,
Since the rotary shaft is composed of two parts, a convex part and a concave part, and the rotor yoke is sandwiched and fixed by these two parts, there is an effect that a device with good assembly workability can be obtained.

According to the invention of claim 7,
Since a sheet-like magnet is mounted on the back surface of the rotor yoke so that the rotating ring of the thrust bearing does not come off from the rotor yoke, there is an effect that a device with good assembly workability can be obtained.

According to the invention of claim 8,
Since the chucking magnet, the index magnet, and the magnet on the back surface of the rotor yoke according to the seventh aspect are integrally formed with the rotor yoke, the number of parts and the number of assembling steps can be reduced, and the cost of the apparatus can be reduced.

According to the present invention of claim 9,
Since the hooking magnet, the index magnet, and the hooking portion for restricting the sliding movement of the sliding member are integrally formed on the rotor yoke, the number of parts and the number of assembling steps are reduced, and the cost of the apparatus can be reduced.

According to the tenth aspect of the present invention, since the inner diameter surface of the concave portion of the rotary shaft end is held by the outer diameter surface of the oil-impregnated metal bearing, the friction load is reduced and the rotation loss is reduced. Is effective.

Further, according to the present invention of claim 11, since the rotary shaft is composed of two parts, the rotary shaft has good machining accuracy, and the concave inner surface of the rotary shaft end is the outer peripheral surface of the oil-impregnated metal bearing. Since the structure is held by, the frictional load is reduced and there is an effect of obtaining a device with less rotation loss.

According to the twelfth aspect of the present invention, the structure is such that the inner diameter surface of the recess at the end of the rotary shaft is held by the outer diameter surface of the oil-impregnated metal bearing, and the ball rotates in the upper part of the recess at the end of the rotary shaft. Since it is freely accommodated and the thrust load of the rotor is held by the upper end of the oil-impregnated metal bearing through the ball, the frictional load in both radial and thrust directions is reduced, and there is an effect of obtaining a device with less rotation loss. .

[Brief description of drawings]

FIG. 1 is a plan view showing a disk drive motor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 1 of the present invention.

FIG. 3 is a partial cross-sectional enlarged view showing a disk drive motor according to Embodiment 1 of the present invention.

FIG. 4 is a partial plan view showing a disk drive motor according to Embodiment 1 of the present invention.

FIG. 5 is a cross-sectional view of essential parts showing a disk drive motor according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 3 of the present invention.

FIG. 7 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 4 of the present invention.

FIG. 8 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 5 of the present invention.

FIG. 9 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 6 of the present invention.

FIG. 10 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 7 of the present invention.

FIG. 11 is a sectional view of a key portion showing a disk drive motor according to Embodiment 8 of the present invention.

FIG. 12 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 9 of the present invention.

FIG. 13 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 10 of the present invention.

FIG. 14 is a sectional view of a key portion showing a disk drive motor according to Embodiment 11 of the present invention.

FIG. 15 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 12 of the present invention.

FIG. 16 is a sectional view of a key portion showing a disk drive motor according to Embodiment 12 of the present invention.

FIG. 17 is a sectional view of a key portion showing a disk drive motor according to a thirteenth embodiment of the present invention.

FIG. 18 is a plan view of a rotor portion of a disk drive motor according to a fourteenth embodiment of the present invention.

FIG. 19 is a sectional view of a key portion showing a disk drive motor according to a fifteenth embodiment of the present invention.

FIG. 20 is a plan view of a rotor portion of a disk drive motor according to a fifteenth embodiment of the present invention.

FIG. 21 is a plan view of a rotor section of a disk drive motor according to a sixteenth embodiment of the present invention.

FIG. 22 is a sectional view of a key portion showing a disk drive motor according to Embodiment 16 of the present invention.

FIG. 23 is a rear view of the rotor portion of the disk drive motor according to the sixteenth embodiment of the present invention.

FIG. 24 is a rear view of the rotor portion of the disk drive motor according to the seventeenth embodiment of the present invention.

FIG. 25 is a cross-sectional view of essential parts showing a disk drive motor according to Embodiment 17 of the present invention.

FIG. 26 is a sectional view of a key portion showing a disk drive motor according to Embodiment 18 of the present invention.

FIG. 27 is a sectional view of a key portion showing a disk drive motor according to Embodiment 19 of the present invention.

FIG. 28 is a fragmentary sectional view showing a disk drive motor according to embodiment 20 of the present invention.

FIG. 29 is a cross-sectional view of essential parts according to Conventional Example 1 showing a conventional disk drive motor.

FIG. 30 is a cross-sectional view of essential parts according to Conventional Example 2 showing a conventional disk drive motor.

FIG. 31 is a cross-sectional view of essential parts according to Conventional Example 2 showing a conventional disk drive motor.

[Explanation of symbols]

1. Rotor 21. Laminated inertia 2. Rotating shaft 22. Thrust bearing 2b. Straight shaft 22a. Rotating wheel 2c. Cap 22b. Fixed wheel 3. Rotor magnet 22c. Ball 4. Rotor yoke 22d. Retainer 9. Oil-impregnated metal bearing 26. Washer for adjusting thrust load 12. Sliding member 27. Sheet-shaped plastic magnet 14. Chucking magnet 30. Locking part 15. Index magnet 31. ball

Claims (12)

[Claims] 1. A rotary inertia load laminated structure in which a rotor yoke formed of a magnetic material in a cup shape, a rotary shaft fixed to the rotor yoke and rotating with the rotor yoke, and a flat washer-shaped thin plate are laminated and fixed to the rotor yoke. A circumferentially opposed rotor having an inertia and a rotor magnet that generates a magnetic force in the radial direction with respect to the rotary shaft, a stator provided circumferentially opposite to the rotor, and fitted to the rotary shaft, An oil-impregnated metal bearing that holds the radial direction of the rotor, and a thrust direction that holds the rotor,
A flat washer-shaped rotating wheel that rotates together with the rotor yoke, a fixed ring having the same shape as the rotating wheel, a plurality of balls sandwiched between the fixed ring and the rotating wheel, and a retainer that rotatably supports the balls. Drive motor with a thrust bearing comprising. 2. A rotary inertia load laminated structure in which a rotor yoke formed of a magnetic material in a cup shape, a rotary shaft fixed to the rotor yoke and rotating with the rotor yoke, and a flat washer-shaped thin plate are laminated and fixed to the rotor yoke. A circumferentially opposed rotor having an inertia and a rotor magnet that generates a magnetic force in the radial direction with respect to the rotary shaft, a stator provided circumferentially opposite to the rotor, and fitted to the rotary shaft, An oil-impregnated metal bearing for rotatably holding the rotor, a sliding member interposed between the back surface of the rotor yoke and the end surface of the oil-impregnated metal bearing, and interposed between the sliding member and the back surface of the rotor yoke, A disk drive motor comprising a washer for adjusting a thrust load that keeps the thrust load of the rotor constant. 3. A rotary inertia load laminate in which a rotor yoke formed of a magnetic material in a cup shape, a rotary shaft fixed to the rotor yoke and rotating with the rotor yoke, and a flat washer-shaped thin plate are laminated and fixed to the rotor yoke. A circumferentially opposed rotor having an inertia and a rotor magnet that generates a magnetic force in the radial direction with respect to the rotary shaft, a stator provided circumferentially opposite to the rotor, and fitted to the rotary shaft, An oil-impregnated metal bearing that holds the rotor rotatably is provided, and the rear surface of the rotor yoke slides on the upper end surface of the oil-impregnated metal bearing. The sliding surface of the rotor yoke has a small friction coefficient and wear resistance. A disk drive motor that has been subjected to a surface treatment of great quality. 4. The rotary shaft of the rotor is configured by fitting two parts of a cylindrical straight shaft and a cap, and has a stepped shape with a small straight shaft diameter. 3. The disk drive motor according to any one of 3 above. 5. The rotary shaft is formed by two parts of the straight shaft and the cap into a stepped shape having a small straight shaft diameter, and the oil-impregnated metal bearing is fitted to the outer periphery of the straight shaft of the rotary shaft. The disk drive according to claim 2 or 3, wherein a radial bearing is formed, and a bottom surface of the cap and an end surface of the oil-impregnated metal bearing are sliding surfaces that support a thrust load of the rotor. motor. 6. The rotating shaft is constructed by fitting two parts of concave and convex parts, one of which has a convex end and the other of which has a concave end, and the rotor yoke is sandwiched between the two parts. The disk drive motor according to claim 1 or 2, wherein the rotor yoke and the rotor yoke are fixed. 7. The disk drive motor according to claim 1, wherein a magnet for positioning a rotating wheel of the thrust bearing is fixed to the back surface of the rotor yoke. 8. The positioning magnet is integrally formed on the rotor yoke together with a chucking magnet for attracting and holding a metal disk hub integrated with a recording medium and a signal generating index magnet corresponding to the rotation of a motor. 8. The disk drive motor according to claim 7, wherein: 9. An outer diameter portion of the sliding member is provided with a protruding portion for restricting relative sliding between the sliding member and the rotor yoke, and a locking portion for restricting sliding movement of the protruding portion is provided for the rotor yoke. 3. A disk according to claim 2, wherein a chucking magnet for attracting the disk hub and a chucking magnet for attracting the disk hub and a signal generating index magnet corresponding to the rotation of the motor are integrally formed on the rotor yoke. Drive motor. 10. A rotary inertia load laminated structure in which a rotor yoke formed of a magnetic material in a cup shape, a rotary shaft fixed to the rotor yoke and rotating together with the rotor yoke, and a flat washer-shaped thin plate are laminated and fixed to the rotor yoke. A circumferentially opposed rotor having an inertia and a rotor magnet that generates a magnetic force in a radial direction with respect to the rotation axis,
Disk drive provided with a stator provided circumferentially opposite to the rotor, a radial bearing fitted to the rotating shaft to hold the rotor in the radial direction, and a thrust bearing holding the rotor in the thrust direction. In the motor, the rotating shaft is formed in a cylindrical shape by boring from a bottom surface, and an oil-impregnated metal bearing is fitted into the hollow-cylindrical cylindrical portion, and by the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the oil-impregnated metal bearing, the rotor is Disk drive motor characterized by comprising a radial bearing of. 11. A rotary shaft of the rotor is formed in a shape having a hollow cylindrical portion by fitting a convex cap on a hollow cylindrical straight shaft, and an oil-impregnated metal bearing is fitted on the hollow cylindrical portion. The radial bearing is constituted by the inner peripheral surface of the cylindrical portion and the outer peripheral surface of the oil-impregnated metal bearing,
11. The disk drive motor according to claim 10, wherein the tip end surface of the convex portion of the cap is held by the upper surface of the oil-impregnated metal bearing to form the thrust bearing. 12. A ball is rotatably housed in an upper part of a hollow cylindrical portion of the rotating shaft, and a thrust load of the rotor is held by the upper end of the oil-impregnated metal bearing through the ball to form the thrust bearing. 11. The disk drive motor according to claim 10, wherein the disk drive motor has a structure.