JPH09154252A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to prevent the worsening of characteristics and reliability by forming a frame and a spindle hub in one united body with a magnetic material and providing non-corrosive material for the spindle hub surface coming into contact with a disk. SOLUTION: A spindle hub and a frame (SH) in one united body 20 has a rubber 21 as non-corrosive material on a spindle hub surface on which a disc 1 is placed, and this is able to prevent a slip of the disc 1 during start and stop of a motor and also prevent rusting. At the center of SH 20, a rotating shaft 11 is attached, and a drive magnet 5 magnetized in multiple polarities is fixed in the inner peripheral portion. At the top surface of SH 20, a clamp magnet (CM) 4 for absorbing a mounting plate 2 is fixed. Generally, a gap is always set between CM 4 and a mounting plate 2, an absorbing force between the top surface of SH 20 and CM 4 becomes larger by the absorbing force between the mounting plate 2 and CM 4, and thus CM 4 will never be disengaged from SH 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for driving a disk of an audio visual device or a computer memory device, which mainly uses a digital disk in the field of OA / AV.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers, large-capacity and small external storage devices have become indispensable. The optical disk device is expected as an external storage device capable of large capacity, low bit cost, random access and disk exchange,
Aiming at youth, development is rapidly progressing with the aim of further miniaturization and thinning. Accordingly, there is a demand for a smaller and thinner disk drive spindle motor. Also, in order to fully disseminate the device itself in these technological innovations, reducing the price of the device itself is an important issue,
There is a strict pursuit of equipment component costs. Further, as a disk / spindle motor, cost reduction is required while maintaining / improving reliability.

Hereinafter, a conventional spindle motor will be described with reference to the drawings. 3 is a conventional plan view of a conventional optical disk spindle motor, FIG. 4 (a) is a sectional view of the structure of the conventional optical disk spindle motor taken along the line OPQRST, and FIG. 4 (d) is a cartridge detection switch of the conventional optical disk spindle motor. FIG. In each figure, the same components are given the same reference numerals. Reference numeral 1 is an optical disk medium (hereinafter referred to as a disk). Reference numeral 2 is a mounting plate made of a ferromagnetic material provided on the disk 1. Reference numeral 3 is a spindle hub that receives the disk 1, and is made of metal such as aluminum.

A rotary shaft 11 is attached to the center of the spindle hub 3 and rotates with the spindle hub 3 and the disk 1 to form the center of rotation. The rotating shaft 11
Are supported by ball bearings 12a and 12b.
The rotational driving force of the spindle motor is generated by the magnetic field generated by exciting the stator coil 9 wound around the stator core 8 by power supply excitation and the multi-pole magnetized drive magnet 5 surrounding the magnetic field. The stator core 8 is fixed to the housing 10. The drive magnet 5 is adhesively fixed to the inner periphery of a frame 6 made of a soft magnetic material, and the frame 6 is fixed to the spindle hub 3 by adhesion or press-fitting, and constitutes a rotor together with the drive magnet 5. A clamp magnet 4 is mounted in the spindle hub 3 and has a function of attracting the disk 1 to the spindle hub 3 by a magnetic attraction force. Reference numeral 4a is a clamp yoke made of a magnetic material that forms a magnetic path of the clamp magnet 4, and is fixed to the spindle hub 3 by adhesion. Reference numeral 7 denotes a chassis having electrical wiring, which is engaged with and fixed to the housing 10. Reference numeral 14 denotes a cartridge detection switch for detecting a cartridge (not shown) that houses the disk 1. When the cartridge is inserted into the apparatus, the spindle motor and the cartridge are arranged with a predetermined distance so that the cartridge can pass above the spindle motor. When the disc 1 is rotated, the entire spindle motor moves in the direction of the disc 1 and attracts the disc 1. After this, whether or not the cartridge is at a predetermined position is detected by the cartridge presence / absence detection knob 14a, and whether or not information can be written on the disk 1 is detected by the write protect detection knob 14b. Reference numeral 14c denotes a switch lead of the cartridge detection switch 14, which is soldered to an electric wiring portion on the chassis 7. Reference numeral 13 is a detection knob 14a of the cartridge and a write protection detection knob 1
4b is a protrusion made of resin or the like for positioning the cartridge at an appropriate position with respect to 4b, and is fixed to the chassis 7 with a screw 19.

Reference numeral 26 is a slide plate formed by pressing a stainless steel material and bending both ends to sandwich the spindle motor.

Reference numeral 17 is a mandrel made of stainless steel or the like having an outer diameter of about φ1. The mandrel 17 is rotatably fitted with a cylindrical member 18 having an outer diameter of approximately φ2, and is press-fitted into a mandrel holder 15 made of resin. The mandrel holder 1
The screw 5 is fixed to the chassis 7 with screws 16 by screws.

The operation of the disc clamp mechanism portion of the optical disc spindle motor of the thin optical disc device configured as described above will be described.

The slide plate 26 has the cylindrical member 1
Since the groove for inserting 8 and holding the spindle motor through the mandrel 17 is formed with an inclination with respect to the axial direction, when the slide plate 26 is moved in the horizontal direction, the cylindrical member 18 is moved. Rotates along the inclination of the groove to raise and lower the entire spindle motor. When the cartridge is inserted into the optical disc device by properly combining the horizontal movement direction of the slide plate 26 and the inclination direction of the groove, the spindle motor is moved in the direction of the disc 1 to attract the disc 1. To do. At this time, the protrusion 13 provided on the spindle motor side is fitted and positioned in the positioning hole provided in the cartridge. Further, after the cartridge detection knob 14a detects the presence / absence of the cartridge, and the protection detection knob 14b detects whether or not the data can be written to the disk 1,
Operates to disk rotation. When the cartridge is taken out, the slide plate 26 moves in the opposite direction, so that the spindle motor separates from the disc 1 (FIG. 3 shows the attracted state of the disc 1).

With the above-described structure, the space in which the cartridge moves up and down is provided in the control circuit of the apparatus as compared with a general mechanism in which the cartridge moves up and down with respect to the spindle motor when the cartridge is inserted and taken out. Since it can be effectively used as a part, the size of the device can be reduced.
It becomes possible to reduce the thickness.

[0010]

However, in the case of the above-mentioned structure, the projection 13 which is conventionally arranged on the chassis side of the optical disk device is added as a part of the functional parts of the spindle motor, and further spindle motor constituent parts are provided. It is necessary to study the thinning and component construction method. In addition, a structure that takes into account the mounting space for the mechanical parts required for lifting and lowering the spindle motor is required, which causes an increase in cost and a decrease in reliability.

For example, in the case where the clamp yoke is removed to make the spindle motor thinner and the clamp magnet is directly adhered and fixed to the aluminum spindle hub, since the clamp magnet does not function as a yoke, the disk attracts. Since the force is reduced and the disk slips when the spindle motor is started / stopped, it becomes difficult to determine the read / write position and the read / write time increases. Further, the adhesion of the clamp magnet may be released during repeated attachment / detachment of the disk, leading to a reduction in reliability as a spindle motor. Furthermore, if a spindle hub is made of iron-based material, rust will occur on the surface on which the disk is placed,
There is a problem that rust adheres to the disc and the optical lens of the device as the disc is repeatedly attached and detached, which causes a data read / write error.

Further, it is necessary to attach a mandrel, which supports a cylindrical member inserted into the groove of the slide plate, to the spindle motor as a mechanism for moving the spindle motor up and down. For example, when the mandrel is attached to the resin mandrel holder and the resin mandrel holder is attached to the chassis of the spindle motor by screwing or press fitting, the mandrel is inserted into the cylindrical member to hold the cylindrical member and the mandrel. After the press-fitting into the mandrel holder, the screwing of the mandrel holder to the chassis of the spindle motor must be done at 3 to 4 places per motor, which increases the number of assembly steps and causes a cost increase. There was a problem.

Further, since the mandrel holder made of resin is interposed between the mandrel and the chassis of the spindle motor, the mounting accuracy is deteriorated, and the mandrel holder is damaged during the disk mounting / dismounting so that the spindle motor does not attract the disk. There was a reliability issue.

When the cartridge detection switch is fixed on the chassis of the spindle motor and the switch leads are soldered, the melted solder is deposited on the switch leads and the solder melts the resin cartridge detection switch body. There is a problem in reliability that flux reaching the contact portion of the cartridge detection switch or flux generated when the solder melts adheres to the contact portion of the cartridge detection switch and loses the function of the contact.

The present invention provides means for solving the above problems while maintaining characteristics such as small size, thin thickness, low cost and high reliability, and realizes the various industrial demands mentioned at the beginning.

[0016]

According to the present invention, a frame and a spindle hub are integrally formed of a magnetic material, and a non-corrosive material is provided on the surface of the spindle hub that comes into contact with the disk. In order to make the spindle motor move up and down in the device, it has a mandrel for holding the mandrel and a cylindrical member rotatably fitted to the mandrel, and the mandrel is directly attached to the bending portion integrally provided on the chassis of the spindle motor. It has a press-fitted configuration, and includes a mandrel for holding the motor up and down in the device for attaching and detaching the motor to and from the disc. The mandrel has a surface hardness higher than that of the slide plate. The lead of the cartridge detection switch for detecting the presence / absence of a disk and whether it is writable is connected to the electrical wiring of the chassis of the spindle motor. Between the and, it is possible to solve the above problems and realize the various industry demands mentioned at the beginning by maintaining the features of small size, thinness, low cost, high reliability, etc. it can.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention includes a rotating shaft, a ball bearing for supporting the rotating shaft, a housing for fixing the ball bearing, a stator core constituting a magnetic circuit, A stator coil wire for generating a magnetic field, a drive magnet for rotating a spindle motor, a frame for holding the drive magnet and fixing it around the rotation shaft, a spindle hub for mounting a disc, and a magnetic attraction for the disc. A spindle magnet, wherein the frame and the spindle hub are integrally formed of a magnetic material, and a non-corrosive material is provided on the surface of the spindle hub that contacts the disk. Due to the configuration, the spindle hub and frame are integrally formed of a magnetic material, which reduces Since the magnetic circuit to adsorb the disk of the clamp magnet in goods can be constructed, the disk and the spindle hub of the slip can strongly magnetic attraction force can be prevented.

Further, since the clamp magnet for magnetically attracting the disk can be fixed directly to the top surface of the frame by utilizing the magnetic attraction force, it is possible to prevent the clamp magnet from coming off the frame. Further, by providing a non-corrosive material in the portion where the disk is placed, it is possible to prevent the deterioration of reliability due to the generation of rust.

According to a second aspect of the present invention, a rotary shaft, a ball bearing that supports the rotary shaft, a housing that fixes the ball bearing, a stator core that forms a magnetic circuit, and a stator coil wire that generates a magnetic field. When,
A drive magnet for rotating the spindle motor, a frame for holding the drive magnet and fixing it around the rotation shaft, a chassis supporting the housing, and a plurality of mandrels fixed to the chassis at right angles to the axial direction. And a cylindrical member rotatably fitted to the mandrel, which is provided in the disc device, is formed so as to sandwich the spindle motor by bending both ends, and is provided with a groove inclined with respect to the axial direction. In a spindle motor of a slide plate having a side plate that is held by inserting the cylindrical member into the groove, a plurality of bent portions parallel to the axial direction are provided integrally with the chassis on an outer peripheral portion of the chassis, A spindle motor characterized in that the mandrel is rotatably fitted to each bent portion and is directly press-fitted into the bent portion. By doing so, the mandrel holder required in the conventional example can be omitted, and the problem that the mandrel holder is damaged when the disc is attached and detached, which is a problem by using the mandrel holder, is solved, and further the mandrel holder is reduced. ， Reduces the number of installation steps and improves the installation accuracy.

According to a third aspect of the present invention, the surface hardness of the mandrel is made higher than that of the slide plate, and the mandrel is directly inserted into the groove of the slide plate without the cylindrical member. According to the spindle motor described in (3) above, the cylindrical member required in the conventional example can be omitted, and an inexpensive spindle motor can be provided.

According to a fourth aspect of the present invention, a rotary shaft, a ball bearing that supports the rotary shaft, a housing that fixes the ball bearing, a stator core that forms a magnetic circuit, and a stator coil wire that generates a magnetic field. When,
A drive magnet for rotating the motor, a frame for holding the drive magnet and fixing it around the rotation shaft, a spindle hub for mounting a disk formed on the top surface of the frame, and an electric wiring for supporting the housing. And a cartridge detection switch which is mounted on the chassis and detects the presence or absence of a disc or whether writing is possible, and the lead of the cartridge detection switch has a connecting portion between the cartridge detection switch and the electrical wiring of the chassis. The spindle motor is characterized by being formed in a convex shape between the two, and when the lead of the cartridge detection switch is soldered on the chassis by this configuration, even if the solder is overfilled, it becomes the convex shape. Molded switch lead protrusions prevent solder flow and Since it is avoided to affect in the resin body part of the detection switch, thereby enabling high solderability reliability without affecting the switch original function.

Embodiments of the present invention will be described below with reference to FIGS. 1, 2 (a), 2 (b) and 2 (c).

(Embodiment 1) FIG. 1 is a plan view of a spindle motor according to Embodiment 1 of claims 1, 2 and 4 of the present invention, and FIG. 2A is a view taken along line UVWXYZ of FIG. 2B is a partial plan view of the spindle motor according to the first embodiment of claim 3 of the present invention. FIG. is there.

In the drawings, parts that are not directly related to the present invention are shown as conventional structures, and the same parts are designated by the same reference numerals and detailed description thereof will be omitted. Reference numeral 1 is an optical disk medium (hereinafter referred to as a disk). Reference numeral 2 is a mounting plate made of a ferromagnetic material provided on the disk 1. Reference numeral 20 denotes a spindle hub integrated frame which is integrally processed. A rubber 21 is provided as a non-corrosive material on the surface of the spindle hub on which the disk 1 is placed, so that the disk 1 slips when the spindle motor is started or stopped. And at the same time prevent the generation of rust. A rotating shaft 11 is attached to the center of the spindle hub integrated frame 20, and a multi-pole magnetized drive magnet 5 is fixed to the inner peripheral portion by adhesion. A clamp magnet 4 for attracting the mounting plate 2 is directly fixed to the top surface of the spindle hub integrated frame 20 by magnetic attraction. Generally, since there is always a gap between the opposing surfaces of the clamp magnet 4 and the mounting plate 2, there is an attraction force between the mounting plate 2 and the clamp magnet 4, so that the spindle hub is Integrated frame 2
The attraction force between the top surface of No. 0 and the clamp magnet 4 becomes larger, and the clamp magnet 4 cannot be detached from the spindle hub integrated frame 20.
With the above-described structure, the clamp yoke, which has been conventionally required, can be omitted, the clamp magnet 4 is disengaged, the disc 1 and the spindle hub integrated frame 20 are slipped, and the disc 1 is placed. Since it is possible to prevent rust from occurring in the parts to be covered, it is possible to provide an inexpensive thin motor in which the number of parts and the number of assembling steps are reduced without lowering the reliability.

Although the non-corrosive material is rubber in the above embodiment, it goes without saying that the same effect can be obtained with other resin materials or non-corrosive metal materials.

In FIG. 1 and FIG. 2 (a), reference numeral 17 denotes the outer diameter φ.
It is a mandrel made of 1 stainless steel. A cylindrical member 18 having an outer diameter of about φ2 is rotatably fitted to the mandrel 17, and the spindle motor is held by inserting the cylindrical member 18 into the groove of the slide plate 26 at four positions. The outer periphery of the chassis 7 is partially bent in parallel to the axial direction, and the mandrel 17 fitted with the cylindrical member 18 is press-fitted into the bent part 23 at a right angle to the axial direction. The holder is omitted. With this configuration, the problem that the mandrel holder is damaged when the disc 1 is attached and detached, which has been a problem due to the use of the mandrel holder, is solved, and further, the mandrel holder is reduced, the mounting man-hour is reduced, and the mounting accuracy is improved. Can be improved.

In FIG. 2 (c), by making the surface hardness of the mandrel 24 higher than that of the slide plate 26, the cylindrical member 18 can be omitted and an inexpensive spindle motor can be provided. Although an example in which the mandrel 24 is press-fitted directly into the bent portion 23 of the chassis 7 has been shown, even if the mandrel 24 is press-fitted into the mandrel holder of the conventional example, the cylindrical member 1
The effect of reducing the number of parts and man-hours that 8 can be omitted is obtained.

In FIG. 2 (b), 14 is a cartridge (not shown) detection switch, and 14d is a switch lead projection formed in the center of the lead of the cartridge detection switch. With this configuration, when the leads of the cartridge detection switch 14 are soldered onto the chassis 7, even if the solder is overfilled, the switch lead convex portion 14d can prevent the solder flow, and the resin main body portion of the cartridge detection switch 14 can be prevented. Since the influence on the inside can be avoided, highly reliable soldering can be performed without affecting the original function of the switch. Further, when a metal substrate is used as the chassis 7, if the metal substrate end face is set immediately below the switch lead convex portion 14d, the switch lead escapes from the metal substrate end face.
The reliability issue of ensuring insulation between the metal substrate and the switch leads is also solved.

In addition, in the first embodiment, the chassis having the electrical wiring can obtain the same effect even if the substrate having the electrical wiring is attached to the chassis.

According to the present embodiment, it is possible to realize a thin type and a low cost without deteriorating the performance and reliability of the spindle motor.

[0031]

As is clear from the above description, the present invention
While maintaining characteristics such as small size and high reliability, it is possible to provide a thin and excellent spindle motor that meets the needs of the industry at low cost.

[Brief description of the drawings]

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

FIG. 2A is a structural cross-sectional view of the spindle motor according to the first embodiment of the present invention taken along the line UVWXYZ. FIG. 2B is a view taken along arrow A of the cartridge detection switch of the spindle motor according to the first embodiment of the present invention. 1 is a partial plan view of a spindle motor according to a first embodiment of the invention.

FIG. 3 is a plan view of a conventional spindle motor.

FIG. 4 (a) OPQRST of a conventional spindle motor
(B) View of the cartridge detection switch of the conventional spindle motor taken along line B

[Explanation of symbols]

 1 Disc 2 Mounting Plate 3 Spindle Hub 4 Clamp Magnet 4a Clamp Yoke 5 Drive Magnet 6 Frame 7 Chassis 8 Stator Core 9 Stator Coil 10 Housing 11 Rotating Shaft 12a, 12b Ball Bearing 13 Protrusion 14 Cartridge Detection Switch 14a Cartridge Detection Knob 14b Light Protect Detection Knob 14c Switch lead 14d Switch lead convex part 15 Mandrel holder 16,19 Screw 17,24 Mandrel 18 Cylindrical member 20 Spindle hub integrated frame 21 Rubber 22 Chassis integrated protrusion 23 Bent part 25 Chassis integrated housing

Claims (4)

[Claims] 1. A rotary shaft, a ball bearing that supports the rotary shaft, a housing that fixes the ball bearing, a stator core that forms a magnetic circuit, a stator coil wire that generates a magnetic field, and a spindle motor that rotates. Drive magnet, a frame for holding the drive magnet and fixing it around the rotation shaft, a spindle hub for mounting a disc, and a clamp magnet for magnetically attracting the disc, and the frame and the spindle hub are A spindle motor which is integrally formed of a magnetic material, and a non-corrosive material is provided on a surface of the spindle hub that comes into contact with the disk. 2. A rotating shaft, a ball bearing that supports the rotating shaft, a housing that fixes the ball bearing, a stator core that forms a magnetic circuit, a stator coil wire that generates a magnetic field, and a spindle motor that rotates. Drive magnet, a frame for holding the drive magnet and fixing it around the rotation shaft, a chassis supporting the housing, a plurality of mandrels fixed to the chassis at right angles to the axial direction, and the mandrel A slide having a cylindrical member rotatably fitted to each other, formed to be inserted into a disk device so as to fold the both ends of the spindle motor and sandwiching the spindle motor, and having a side plate having a groove inclined with respect to the axial direction. In a spindle motor held by inserting the cylindrical member into the groove of a plate, the outer peripheral portion of the chassis , Spindle motor, wherein a bent portion parallel to the plurality of axially and pressed the chassis and integrally provided with, directly said mandrel at each bent portion fitted rotatably said cylindrical member. 3. The spindle motor according to claim 2, wherein the surface hardness of the mandrel is made higher than that of the slide plate, and the mandrel is directly inserted into the groove of the slide plate without using the cylindrical member. 4. A rotary shaft, a ball bearing that supports the rotary shaft, a housing that fixes the ball bearing, a stator core that constitutes a magnetic circuit, a stator coil wire that generates a magnetic field, and a motor rotation. A drive magnet, a frame that holds the drive magnet and fixes the rotary shaft as a center, a spindle hub on which a disc formed on the top surface of the frame is mounted, and a chassis that supports the housing and is electrically wired. The cartridge detection switch is mounted on the chassis and detects whether there is a disc or whether writing is possible.The lead of the cartridge detection switch has a convex shape between the cartridge detection switch and the connection portion of the electric wiring of the chassis. A spindle motor characterized by being molded into.