JP3688015B2 - motor - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a motor for rotationally driving a recording disk such as a magneto-optical disk, and more particularly to a motor in which a support member is caulked and fixed to a base plate.
[0002]
[Prior art]
FIG. 10 shows a sectional view of a conventional example of a motor for rotationally driving a recording disk such as a magnetic disk. The stationary member of the motor is fitted into a bracket 52 formed by pressing a disk-shaped iron plate plate fixed to the recording apparatus main body 50 and a hole portion 54 provided at the center of the bracket 52 and fixed by caulking. The hollow cylindrical bearing support member 56 is provided. A step portion 56 a is formed on the outer periphery of the bearing support member 56, and an annular stator core 58 is fitted and fixed to the bearing support member 56 so that the inner peripheral side lower surface is in contact with the step portion 56 a. A stator coil is wound around the stator core 58.
[0003]
A rotating member 62 is rotatably supported on the inner periphery of the bearing support member 56 via a pair of ball bearings 60 and 61. The rotating member 62 has a cylindrical shaft portion 64 at the center and a rotor hub portion 66 that spreads out in a disk shape outward from the upper end of the shaft portion 64. On the outer periphery of the rotor hub portion 66, an annular outer wall portion 66a and a flange portion 66b on the outer periphery of the outer wall portion 66a are provided. A recording disk 68 is mounted on the upper surface of the flange portion 66a, and an annular rotor yoke 70 is externally fitted and fixed so as to contact the outer peripheral surface of the outer wall portion 66a and the lower surface of the flange portion 66a. An annular rotor magnet 72 is fixed to the inner peripheral surface of the hanging portion 70a provided on the inner surface.
[0004]
The rotating member 62 is rotationally driven on the upper surface of the bracket 52 by supplying a predetermined exciting current to the stator coil via the flexible circuit board 74 that is bonded and fixed. In addition, a resilient member 65 is mounted in a concave groove 64a provided in an arc shape on the shaft portion 64 side at a portion with the shaft portion 64 with respect to the ball bearing 60. This is taken into consideration so that the inner circumference of the ball bearing 60 is pressed so that the rotating member 62 is tilted in a fixed direction, and the influence of the rotating vibration of the rotating member 62 on the head 76 is substantially eliminated. The pressing direction is a direction perpendicular to the head 76 for reading from and writing to the storage disk 68, and does not affect reading and writing.
[0005]
[Problems to be solved by the invention]
The motor configured as described above has the following problems. That is, first, the bearing support member 56 is inserted into the hole 54 of the bracket 52 at its lower end, and the bracket 52 is deformed into the bracket 52 by plastic deformation of the annular groove 57 provided at the outer peripheral edge of the lower end surface of the bearing support member 56. It is fixed by crimping. However, when the hole 54 is formed, the bracket 52 is distorted and it becomes difficult to maintain the flatness. Further, when the bearing support member 56 is pressurized and plastically deformed, it is formed on the peripheral edge of the lower surface of the hole 54 of the bracket 52. There is a problem that a protrusion is formed, and the motor cannot be mounted horizontally on the recording apparatus main body 50 due to the protrusion.
[0006]
Second, there is a problem that it is extremely difficult and troublesome to mount the resilient member 65 mounted on the shaft portion 64 in the annular groove 64a. An object of the present invention is to solve such a conventional problem, and can perform caulking without making a business trip to the lower surface of a bracket made of an iron plate, and can easily eliminate the influence of rotational runout. Is to provide.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the motor of the present invention, a base plate, a support member erected on the base plate, bearing means mounted on the support member, and rotation supported by rotation through the bearing means Member, a rotor magnet provided on the rotating member, and a stator provided opposite to the rotor magnet, and the support member is inserted into a hole provided in the base plate, and this support The support member is fixed to the base plate by plastic processing of the insertion end of the member. A peripheral portion of the hole is provided with a defective portion formed in the circumferential direction and a tapered portion that accommodates a plastic deformation portion at the insertion end of the support member, and is generated by the defective portion when the tapered portion is formed. Process distortion is absorbed.
[0008]
It is desirable that the defect portion has a plurality of notches in the peripheral edge portion.
[0009]
[Action]
In the motor having the above-described configuration, the hole portion is provided with a deficient portion at the peripheral portion and a tapered portion formed by plastic working, so that when the tapered portion is plastic processed, Protruding or the like to other parts that occur is absorbed by the missing part, and the base plate can form a tapered part while maintaining a flat state. In addition, since the deformed portion deformed by the plastic processing of the insertion end of the support member is accommodated in the tapered portion, the support member is fixed while maintaining the planar state of the base plate.
[0010]
Further, if the defect portion has a plurality of notches in the peripheral edge portion, the defect portion can be formed by a simple method.
[0011]
【Example】
The present invention will be described below with reference to the drawings illustrating embodiments. FIG. 1 is a cross-sectional view of an embodiment of a motor according to the present invention, which is a motor for rotationally driving an optical disc. FIG. 2 is a bottom view of FIG.
[0012]
As shown in FIG. 1, the motor has a base plate 2 fixed to a drive device (not shown) made of a ferromagnetic material such as iron, and a rectangular portion 2 a as shown in FIG. 2 due to the space of the device. From the two sides of the rectangular portion 2a, the first enlarged surface portion 2b and the second enlarged surface portion 2c and, further, from the other side of the rectangular portion 2a, a substantially semicircular portion 2e aligned with the outer periphery of the stator core described later spreads on a plane. It has a shape. A hole 2d is provided at the center of the rectangular portion 2a, and a hollow cylindrical bearing support portion 4 is inserted into the hole 2d, and is fastened and fixed to the outer peripheral groove 4e on the lower end surface of the bearing support member 4. Yes.
[0013]
The bearing support member 4 is formed by integrally forming a small cylindrical portion 4a having a small inner diameter, a large cylindrical portion 4b having a large inner diameter, and an annular protrusion 4c on the outer periphery of the small cylindrical portion 4a. The base plate 2 is in contact with the lower surface of the small cylindrical portion 4 and the outer peripheral surface of the small cylindrical portion 4a. Further, the stator 6 is fitted so as to contact the upper surface of the protrusion 4c and the outer peripheral surface of the large cylindrical portion 4b, and the upper end surface of the large cylindrical portion 4b is crimped and fixed. The stator core 6a has a shape in which the outer peripheral portion is bent obliquely downward in order to match the magnetic center in accordance with the positional relationship with the rotor magnet 22 described later, and the space limitation associated with downsizing is taken into consideration.
[0014]
On the other hand, an annular step 4d is formed in the bearing support member 4 due to the difference in inner diameter between the small cylindrical portion 4c and the large cylindrical portion, and is in contact with the inner peripheral surface of the large cylindrical portion 4b and the step 4d. A ball bearing 8 is attached to the inner periphery of the small cylindrical portion 4a, and an oil-impregnated porous sleeve bearing 10 is attached to the inner peripheral surface of the small cylindrical portion 4a.
[0015]
A cylindrical rotating shaft 12 is inserted and supported rotatably by these bearings, and the screw 13 attached to the lower end surface of the rotating shaft 12 prevents the rotating shaft 12 from coming off. The screw 13 has a flange portion 13a larger than the diameter of the rotary shaft 12, and the flange 13a prevents the rotary shaft 12 from coming off.
[0016]
As shown in FIG. 3, the screw 13 also has an effect of preventing mist-like lubricating oil from leaking from the bearing surface 10 a of the sleeve bearing 10. This is because mist-like or liquid lubricating oil is held in the accommodating portion 11 formed as a minute gap by the concave portion 10b and the flange portion 13a of the sleeve bearing 10, and adheres to the surface of the sleeve bearing 10 as indicated by an arrow in the figure. It is absorbed and circulates again as lubricating oil. Therefore, the lubricating oil does not easily flow out to the outside and can be used as a bearing having a long life.
[0017]
Above the rotating shaft 12, a rotor holder 14 formed of iron material by dish-like pressing is fitted and fixed, and an annular clamp magnet 16 is bonded and fixed on the rotor holder 14.
[0018]
A rotor hub 18 made of an aluminum material is fitted and fixed to the outer peripheral surface of the peripheral wall portion 14a formed on the outer peripheral edge of the rotor holder 14. The rotor hub 18 is integrally formed with an annular portion 18a having a large thickness, a hanging portion 18b that hangs down from the lower end surface of the outer periphery of the annular portion 18a, and an outer diameter portion 18c that bends radially outward from the tip. . Further, a rotor yoke 20 made of an annular and magnetic stainless material is fitted to the tip of the outer diameter portion 18c, and the rotor magnet is brought into contact with the lower surface of the outer diameter portion 18c and the inner peripheral surface of the rotor yoke 20. 22 is fixed.
[0019]
The three members (the rotor holder 14, the rotor hub 18, and the rotor yoke 20) that are these rotating members are considered as follows. The rotor holder 14 uses a magnetic material in order to increase the magnetic force of the clamp magnet 16. The rotor hub 18 is made of an aluminum material so that it can be easily cut. This is because the optical disk 24 is placed on the upper surface of the annular portion 18a, which is suitable for high-precision planar processing. The rotor yoke 20 uses a magnetic material to increase the magnetic force of the rotor magnet 22. Here, the rotor hub 18 is made of a non-magnetic material (aluminum material) because the magnetic flux from the stator core 6a is focused on the rotor magnet 22 without going to the non-magnetic rotor hub 18, as shown in FIG. For this reason (see the arrow), the magnetic interaction with the rotor magnet 22 can be improved. On the other hand, as shown in FIG. 4B, when the rotor hub 18 ′ is made of a magnetic material in which the rotor hub and the rotor yoke are integrated, the magnetic flux from the stator core 6a goes not only to the rotor magnet 22 but also to the rotor hub 18 ′, so that the magnetic flux is dispersed. Since the magnetic interaction with the rotor magnet 22 is lower than that in the case of FIG. 4A, the configuration of FIG. 4A is adopted.
[0020]
In the rotor magnet 22, the stator core 6a faces in the radial direction, and in the axial direction, the rectangular portion 2a of the base plate 2 faces the rotor magnet 22 with a slight gap as shown in FIG. Therefore, the rotor magnet 22 magnetically attracts not only the stator core 6a but also the base plate 2 that is a magnetic body, but as shown in FIG. 1, the substantially semicircular portion 2e is provided only up to a position corresponding to the stator core 6a. There is no magnetic attraction.
[0021]
This has the following two advantages. First, the rotor magnet 22 exerts an unbalanced magnetic attraction force due to the circumference of the base plate 2, and the rotation shaft 12 is directed in the direction opposite to the semicircular portion 2 e with respect to the rotation axis K (the arrow in FIG. 1). ) It is inclined to A (this means that a magnetic side pressure is applied to the rotary shaft 12). This can prevent the rotating shaft 12 from swinging and rotating by tilting the rotating shaft 12 in a specific direction, and can improve the rotation accuracy. This direction A must be a direction perpendicular to a straight line L connecting the read / write head H and the center point O of the disk provided in the drive device as shown in FIG. This is because the optical disk 24 is tilted as the rotary shaft 12 is tilted. However, since this tilt is always limited to a specific direction, the distance relationship between the head H and the optical disk 24 is kept constant, causing an operation error of the head H. Because there is nothing.
[0022]
Therefore, an eddy current is likely to be generated in the base plate 2 and an eddy current loss due to Joule heat is caused. This causes a reduction in rotational efficiency. However, the area of the base plate 2 is reduced by deleting a part of the opposing surface of the rotor magnet 22 that generates a large amount of eddy current, such as the substantially semicircular portion 2e, without reducing the function of the base plate 2. Therefore, eddy current loss can be reduced.
[0023]
When the disc is loaded on the drive device equipped with the above motor, the optical disc 24 is attracted and held by the magnetic attraction force of the clamp magnet 16 placed on the rotor hub 18. The rotor hub 18 is rotationally driven by supplying a predetermined exciting current to the stator coil via the flexible circuit board 26 bonded and fixed to the base plate 2. When the optical disk is loaded, the motor is lifted up to a predetermined position in the axial direction. Guide pins 28 and 28 for guiding the motor to the position through a guide path (not shown) on the drive device side are provided on the base plate 2. The rectangular portion 2a is provided. As shown in FIG. 5, the guide pin 28 is formed with three cuts along the side of the rectangular part 2a to form a band part, and from its ends, a first band part 30a, a second band part 30b, and a third band are formed. This is referred to as a part 30c. Then, the first belt portion 30a and the third belt portion 30c are plastically processed in a semicircular shape on the lower surface side, and the second belt portion 30b is plastically processed in a semicircular shape on the upper surface side. Thus, the insertion hole 32 is formed by the three belt portions, and the guide pin 28 is press-fitted and fixed to the insertion hole 32, and the guide pins 28 and 28 are fixed easily and firmly.
[0024]
Details of fixing the support member 4 will be described below with reference to FIGS. 6 and 7. As shown in FIG. 6, the hole 2 d of the base plate 2 is formed with a deficient portion 5 a with the peripheral portion removed in a V shape, and the portion that protrudes and remains is V-shaped. Called. As shown in FIG. 7, a tapered portion 5b having an angle θ of approximately 45 degrees is formed on the lower end surface of the V-shaped protrusion 5 (the back surface of the base plate 2). And the outer peripheral surface of the small cylindrical part 4a of the bearing support member 4 is contact | abutted to the V-shaped protrusion part 5, and this outer peripheral part 4f is plastically processed. The outer peripheral edge portion 4f is deformed toward the tapered portion 5b, and the bearing support member 4 is fixed to the base plate 2. Therefore, the bearing support member 4 is fixed to the back surface of the base plate 2 in a state where the flat surface is maintained without causing a bulge or the like due to plastic working.
[0025]
The taper part 5a may change an angle according to the deformation amount of the outer peripheral edge part 4f to be plastically processed. The amount of deformation is determined by the shape of the fixed member (the bearing support member 4 in the embodiment) with respect to the thickness of the plate. For example, in the case of a thinner plate, the contact surface with the member to be fixed is reduced, and the angle θ is reduced because it is necessary to increase the amount of deformation.
[0026]
Next, an assembly method for assembling the bearing support member 4 in the hole 2d of the base plate 2 will be described with reference to FIG. First, the rectangular portion 2a is punched out by a press machine to form a hole 2d having a V-shaped protrusion 5 and a missing portion 5a as shown in FIG. Then, as shown in FIG. 8A, the base plate 2 is placed on the press stand P <b> 1 so that the press can be pressed from the back surface side of the base plate 2. The press part P of the press machine is a cylindrical shape having a diameter slightly larger than the inner diameter of the hole 2d, and a taper t of approximately 45 degrees is formed on the periphery of the upper surface.
[0027]
When the press part P is inserted into the hole 2d as shown in FIG. 8 (b), the V-shaped protrusion 5 of the hole 2d is pressed, so that the tapered part 5b is formed in the V-shaped protrusion 5. . At this time, since a great amount of pressure is momentarily applied to the V-shaped projecting portion 5 and plastic processing is performed, there is a possibility that bulging or the like may occur in other portions with the formation of the tapered portion 5b. However, since the defect portion 5a is provided in the hole portion 2d, the influence of the protrusion or the like of the V-shaped protrusion 5 is absorbed by the defect portion 5a, and the base plate 2 can maintain a flat state.
[0028]
Further, as shown in FIG. 8C, the bearing support member 4 is inserted into the hole 2d from the surface of the base plate 2, and the lower surface of the projection 4c and the outer peripheral surface of the small cylindrical portion 4a are brought into contact with the base plate 2. Then, the annular groove 4e on the lower end surface of the small cylindrical portion 4a is pressed with a caulking tool (not shown), and the outer peripheral edge portion 4f of the small cylindrical portion 4a is plastically processed toward the tapered portion 5b, thereby bearing support member 4 Is fixed to the base plate 2. In addition, during the plastic working of the outer peripheral edge 4f, a large amount of pressure is applied to the peripheral edge of the hole 2d including the V-shaped protrusion 5, so that a bulge or the like may occur, but the defect 5a This will not occur because the stress is absorbed by.
[0029]
Further, the shape of the V-shaped protrusion 5 is such that the contact surface with the bearing support member 4 is ensured over the entire circumference, and the V-shaped chipped portion 5a is a bulge formed by plastic working of the tapered portion 4f and the bearing support member 4 or the like. Suitable for absorbing. Alternatively, if more fixing strength is required, a sufficient contact surface with the member to be fixed can be secured by making the protrusion 5 ′ trapezoidal as shown in FIG.
[0030]
As mentioned above, although the Example of the motor according to this invention was described, this invention is not limited to this Example, A various deformation | transformation is possible, without deviating from the scope of the present invention. For example, in the embodiment, the case of the shaft rotation type motor in which the shaft rotates is shown, but the case of the shaft fixed type motor in which the shaft is fixed can be similarly implemented. That is, the motor has a configuration in which a hole for fixing the shaft is provided in the base plate, which is a stationary member, and the insertion end of the shaft is plastically processed and fixed. Further, the same effect can be obtained even if the defect 5a in the hole 2a is not cut out as shown in FIG.
[0031]
【The invention's effect】
Since the present invention is configured as described above, the following effects can be obtained. That is, since the hole portion of the base plate has a defect portion at the peripheral portion, when the taper portion is formed by plastic working, the protrusion to other parts is absorbed by the defect portion and the base plate is in a flat state. Can be maintained. In addition, since the deformed portion deformed by the plastic processing of the insertion end of the support member is accommodated in the tapered portion, the support member is fixed while maintaining the planar state of the base plate. In this case, if the defect portion has a plurality of notches in the peripheral edge portion, the defect portion can be formed by a simple method.
[0032]
Further, since the base plate is made of a ferromagnetic material and a part of the base plate facing the rotor magnet is removed as a missing part, the rotor magnet magnetically attracts the base plate in an unbalanced state, and the rotating member Can be inclined in a specific direction with respect to the rotational axis. Therefore, it is possible to prevent the rotation shaft from rotating and rotating, and to improve the rotation accuracy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a motor according to the present invention.
FIG. 2 is a bottom view of FIG.
FIG. 3 is an enlarged view of a main part of FIG. 1;
4A is an enlarged view of a main part of FIG. 1, and FIG. 4B is an enlarged view of a main part of another motor.
FIG. 5 is an enlarged view of a main part of FIG. 1;
6 is an enlarged view of a main part of FIG. 1. FIG.
FIG. 7 is an enlarged view of a main part of FIG.
FIG. 8 shows a part of a method for assembling a motor according to the present invention.
FIG. 9 is an enlarged view of a main part showing a modified example of the motor according to the present invention.
FIG. 10 is an enlarged view of a main part showing a modification of the motor according to the present invention.
FIG. 11 is a cross-sectional view showing a conventional motor.
[Explanation of symbols]
2 Base plate 2d Hole part 4 Bearing support member 4a Small cylindrical part 4f Outer peripheral edge part 5 V-shaped protrusion part 5a Defect part 5b Tapered part 6 Stator 8 Ball bearing 10 Sleeve bearing 12 Rotating shaft 14 Rotor holder 18 Rotor hub 22 Rotor magnet

Claims (3)

A base plate, a support member erected on the base plate, bearing means mounted on the support member, a rotary member rotatably supported via the bearing means, and a rotor magnet provided on the rotary member; A stator provided facing the rotor magnet,
In the motor in which the support member is inserted into a hole provided in the base plate by being fitted, and the insertion end of the support member is plastically processed, so that the support member is fixed to the base plate.
A peripheral portion of the hole is provided with a missing portion formed in the circumferential direction and a tapered portion that accommodates a plastic deformation portion at the insertion end of the support member,
A motor that absorbs machining distortion generated when the tapered portion is formed by the defective portion.   The motor according to claim 1, wherein the defect portion has a plurality of notches in the peripheral edge portion.   The base plate is formed of a ferromagnetic material, and the rotating member is inclined in a specific direction with respect to the rotation axis by a magnetic attraction force between the rotor magnet and the base plate at a portion of the base plate facing the rotor magnet. The motor according to claim 1, wherein a defect portion is provided in the motor.

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