JPH06339245A - Miniature motor with turntable and its bearing device - Google Patents

Abstract

PURPOSE:To provide a miniature motor with a turntable, for which the overall length of motor can be considerably shortened without danger of contact between rotor and casing. CONSTITUTION:A rotating shaft 26 is supported in a freely rotatable manner by a casing 23 with the whole of the upper end portion opened, a stator 22 installed to the inside of a casing 23 and a bearing device 24 and is installed to a rotor 25 having an armature 27 opposite the stator and to the rotating shaft. And a turntable 43 covering an open portion 44 of the casing is provided by holding a gap w between the turntable and an end edge 30 at the open side of the casing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor with a turntable, and more particularly to a small motor with a turntable used in audio / visual equipment such as a CD (compact disc) player.

[0002]

2. Description of the Related Art A disc player such as a CD player is
By rotating a disc, such as a CD, an LD (laser disc), a CD-ROM (compact disc-ROM) or an MD (mini disc), in which information is stored at a high density by a small motor with a turntable, the information is stored. Read and play this.

Among the portable type portable disc reproducing apparatuses, the miniaturization and thinning of the apparatus have been particularly advanced. For example, in a mini disc system for reproducing an MD (diameter of about 64 mm) that is about half the size of a CD (diameter of about 120 mm), a portable disc reproducing device that fits in a pocket has already been proposed. . In such a disc reproducing apparatus, it is required to further reduce the motor overall length of a small motor with a turntable mounted therein to make it compact and thin.

FIG. 9 is a front sectional view of a conventional small motor with a turntable used in a disc reproducing apparatus. As shown in the figure, a small motor 1 with a turntable includes a casing 3 in which a stator 2 is attached,
The rotor 4 is provided inside the casing 3, and the rotating shaft 7 of the rotor 4 is rotatably supported by bearings 5 and 6 provided at the upper and lower portions of the casing 3.
A brush 9 is attached to the bottom plate 8 of the casing 3, and the brush 9 is slidably engaged with a commutator 10 provided on the rotating shaft 7. A turntable 11 on which a disc such as a CD is placed is attached to the upper portion of the rotary shaft 7.

When the small motor 1 having the above-mentioned structure is attached to the disc reproducing apparatus, the cover plate 13 of the casing 3 is brought into close contact with the back surface 15 of the device mounting plate 12 of the disc reproducing apparatus and fastened and fixed by the screws 14.

[0006]

In the small motor 1, the gap d ₁ for the head of the screw 14 (the gap between the lower surface of the turntable 11 and the device mounting plate 12) and the plate of the device mounting plate 12 are used. It is necessary to secure the thickness d ₂ , the plate thickness d ₃ of the casing cover plate 13, and the gap d ₄ between the cover plate 13 and the rotor ₄ , respectively. Therefore, there is a problem in that the axial size (motor total length) of the conventional small-sized motor 1 is long. Therefore, the lower surface 17 of the turntable 11 and the casing bottom plate 8
The distance H ₁ between and was large.

Usually, the rotor 4 is provided with play so that it can be slightly reciprocated in the axial direction. When this play is, for example, about 0.2 to 0.3 mm, the gap d ₄ is defined as Requires about 0.5 mm. If the gap d ₄ is made sufficiently large, the entire motor length becomes long, and conversely, if the gap d ₄ is made small, there is a risk that the rotor 4 will contact the inner surface of the lid plate 13.

The present invention has been made in order to solve the above problems, and provides a small motor with a turntable which can shorten the total length of the motor and does not have a risk of contact between the rotor and the casing. With the goal.

[0009]

In order to achieve the above-mentioned object, a small motor with a turntable according to the present invention comprises a casing whose one end is entirely open, and a stator mounted inside the casing. , A rotary shaft is rotatably supported by a bearing device mounted on the casing, and a gap is maintained between a rotor facing the stator and the rotary shaft mounted on the rotary shaft. And a turntable that covers the casing opening.

It is preferable that a recess is formed on the back surface of the turntable and a part of the rotor is housed in the recess. Further, an armature of the rotor or a permanent magnet may be embedded in the recess.

A bearing device for a small motor with a turntable according to the present invention supports a rotary shaft of a rotor having a turntable mounted on the upper part thereof in a cantilevered manner, and a bottom plate of a casing having a stator therein. It is provided with a fixed tubular member and a thrust support member which is provided on the upper end surface of the tubular member and supports the rotor in the thrust direction.

[0012]

In the small motor with a turntable of the present invention, the casing opening portion is opened by the turntable attached to the rotating shaft without opening the entire end portion on the lid plate side without providing the casing with the lid plate as in the prior art. Covers. This makes it possible to bring the turntable closer to the rotor,
Further, the turntable and the armature of the rotor or the permanent magnet can be integrated.

Further, in the bearing device of the present invention, since the tubular member extending in the axial direction supports the rotating shaft in a cantilevered manner, it is not necessary to provide bearings separately in the upper and lower directions. As for the thrust direction, the thrust support member provided on the upper end surface of the tubular member supports the load of the rotor and the turntable. As a result, the turntable and the rotor rotate while being mounted on the tubular member via the thrust support member.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

(First Embodiment) FIGS. 1 to 4 are views showing a first embodiment of the present invention. FIG. 1 is a front sectional view of a small motor with a turntable, and FIG. 2 shows a structure of a bearing device portion. Enlarged sectional view, FIG. 3 is a front view showing the appearance of the small motor,
FIG. 4 is a plan view of FIG.

As shown in FIG. 1, a small motor 20 with a turntable according to the present invention includes an optical disc 21 such as a CD.
Is a direct drive type motor, and the small motor 20 with a turntable of this embodiment is a DC motor with a brush. The small motor 20 includes a casing 23 in which a stator 22 is attached, and a rotor 25 supported by a bearing device 24 attached to the casing 23. Rotating shaft 26 of rotor 25
Are rotatably supported by a bearing device 24. The rotor 25 has an armature 27 that faces the stator 22.

The casing 23 is formed of a metal material such as a cold-rolled steel sheet made of mild steel into a hollow cylindrical shape with a bottom, and the surface of which is galvanized, and one end is entirely open. have. Casing 23
Is a disk-shaped bottom plate 28, and a side plate 29 that is integrated with the bottom plate 28 and that is entirely opened above to form a casing opening portion 44.
A pair of flanges 3 formed on the same plane as the open-side upper edge 30 of the side plate 29 and integrally formed in the left-right direction.
1 and. The flange 31 is formed with a through screw hole 32 for fastening the flange 31 with a screw 61 to a device mounting plate 60 of a disc reproducing device such as a CD player.

The stator 22 is fixed to the cylindrical inner peripheral surface of the casing side plate 29, and is composed of a pair of permanent magnets 22 formed in an arc segment shape by a magnetic material such as hard ferrite.

The rotor 25 has a rotating shaft 26 extending in the direction of a central axis which is the center of rotation, and an armature winding 33 attached to the rotating shaft 26 and wound around a core 34 in a coil shape. The armature 27 is provided with a rotational force, and a commutator 35 assembled into a cylindrical shape and attached to the rotary shaft 26 and electrically connected to the armature 27. The armature 27 is arranged inside the permanent magnet 22 via a predetermined gap.

As shown in FIGS. 1 and 2, a bottomed cylindrical commutator support member 36 is fixed to the rotary shaft 26, and an annular projection 36a is formed on the outer peripheral surface of the commutator support member 36. It is formed integrally. The commutator 35 is the commutator support member 3
It is fixed to a predetermined position in the axial direction by fitting on the outer peripheral surface of 6 and closely contacting the lower surface of the protrusion 36a.

A cylindrical projecting portion 37 is formed in the central portion of the casing bottom plate 28 by drawing, and the cylindrical projecting portion 3 is formed.
The bearing device 24 is fixed to 7.

A plurality of sets (for example, two sets) of brushes 40 made of a conductor material are attached to the casing bottom plate 28 via brush holders 41 made of an insulating material,
Each brush 40 is slidably engaged with the commutator 35 and is electrically connected to a lead wire 42 (FIG. 4) connected to a power source.

A turntable 43 for mounting the disk 21 is attached to the rotary shaft 26, and the turntable 43 holds a predetermined gap w between the turntable 43 and the open side edge 30 of the casing 23. It covers the casing opening portion 44. In order to prevent the head of the screw 61 screwed into the through screw hole 32 from coming into contact with the turntable 43, the through screw hole 3
2 is located radially outward of the outer peripheral edge 62 of the turntable 43.

The bearing device 24 has a turntable 4 at the top.
And a tubular member 45 fixed to a bottom portion 28 of a casing 23 having a stator 22 therein, while rotatably supporting a rotary shaft 26 of a rotor 25 to which 3 is attached.
A plate-shaped washer 47 is provided on the upper end surface 46 of the tubular member 45 and serves as a thrust support member that supports the rotor 25 in the thrust direction. Rotating shaft 26, tubular member 4
5, the commutator support member 36 and the commutator 35 have a coaxial structure in which the centers of rotation are the same.

The tubular member 45 is press-fitted and fixed inside the tubular projecting portion 37 of the casing bottom plate 28. Tubular member 4
Since 5 is made of iron-copper-based powder sintered metal or powder sintered alloy impregnated with lubricating oil, the rotary shaft 26 smoothly rotates in the tubular member 45. The tubular member 45 has a cylindrical shape that is long in the axial direction in order to support the rotating shaft 26 in the radial direction.

As shown in FIG. 1, the central position C ₁ of the magnetic force of the armature 27 is slightly above the central position C ₂ of the magnetic force of the permanent magnet 22 (hereinafter, the direction of the turntable 43 is referred to as the upward direction). The rotor 25 is always pulled in the direction opposite to the turntable (downward) by the magnetic attraction force. This downward pulling force, the rotor 25,
Gravity generated by the turntable 43 and the disk 21 is supported by the washer 47 and the tubular member 45.

The plate-shaped washer 47 is made of polyester resin and is formed into an annular shape.
A load is applied to the through the commutator support member 36. The washer 47 is not fixed to either the tubular member 45 or the commutator support member 36 and is free to rotate, and its sliding portion becomes high temperature due to frictional heat. Further, since a large current flows through the sliding contact portion between the commutator 35 and the brush 40 to generate heat, the commutator support member 36 is also heated by the commutator 35 having a high temperature. Therefore, the commutator support member 36 is preferably made of heat-resistant glass fiber resin.

A stopper ring 48 is provided below the rotary shaft 26.
Are positioned and fixed below the tubular protrusion 37.
The stopper ring 48 prevents the rotor 25 from coming out upward.

In the small motor 20 with a turntable having the above structure, when a current is passed from the lead wire 42 to the armature 27 through the brush 40 and the commutator 35, the magnetic field formed by the pair of permanent magnets 22 is generated. A rotational force is applied to the existing rotor 25, and the rotor 25 makes a rotational motion.

As a result, the rotary shaft 26 and the turntable 43 rotate, and the C mounted on the turntable 43 is rotated.
Optical disc 2 such as D, LD, CD-ROM or MD
1 rotates, and the optical pickup device reads and reproduces the information recorded on the optical disc 21.

As described above, in the small motor with turntable 20 according to the present invention, one end of the casing 23 is entirely opened and the casing opening 44 is covered with the turntable 43. The table 43 can be brought closer to the direction of the armature 27 that rotates with the turntable 43. When the turntable 43 is made of synthetic resin, the turntable 43 may be brought into contact with the armature 27.

It suffices to secure only the gap w with which the turntable 43 which makes a rotary motion does not come into direct contact with the upper end edge 30 of the casing 23 on the open side. That is, it is necessary in the present invention to secure the gap for the head of the motor mounting screw, the plate thickness of each of the device mounting plate and the casing cover plate, and the gap between the rotor and the casing, which are conventionally required. There is no. Therefore, the distance H ₂ between the turntable rear surface 49 and the outer surface of the casing bottom plate 28 becomes smaller,
The overall motor length (axial dimension) is greatly reduced without degrading the motor performance. For example, while the conventional motor requires a total motor length of about 12 mm, the motor of the present invention has a total motor length of about 8 mm, which is significantly shortened.

Conventionally, a bottom plate of the casing was separately required, but in the present invention, the entire casing 23 can be integrally formed, so that the manufacturing is easy and the conventional casing lid plate portion on the turntable 43 side is provided. Since it is unnecessary, the casing 23 can be significantly reduced in weight.

The bearing device 24 is composed of a tubular member 45 for supporting the rotor 25 in the radial direction and a washer 47 for supporting the rotor 25 in the thrust direction. However, substantially one tubular member 45 serves as the rotor 25. Since the shaft is supported, it is not necessary to provide bearings at the upper and lower portions as in the conventional case, and the structure of the bearing device is simplified.

(Second Embodiment) FIG. 5 is a front sectional view of a small motor 20a with a turntable according to a second embodiment of the present invention. As shown, in this embodiment, the back surface 4 of the turntable 43a attached to the rotary shaft 26 is
A recess 50 is formed in the recess 9 a, and a part of the armature 27 attached to the rotary shaft 26 is housed in the recess 50.

That is, an annular recess 50 concentric with the rotary shaft 26 is formed on the turntable rear surface 49a, and the armature 27
Part of the armature winding 33 is housed in the recess 50.
As a result, the space conventionally occupied by the turntable can be used for housing the armature winding 33, and the turntable 4
3a can be brought closer to the armature 27 side. Therefore, the total length of the motor can be further shortened without degrading the performance of the motor. The armature winding 33 has the recess 5
The turntable 43a may be brought closer to the armature 27 side as it contacts 0. The configuration of the other parts is the same as that of the first embodiment.

(Third Embodiment) FIG. 6 is a front sectional view of a small motor 20b with a turntable according to a third embodiment of the present invention. As shown in the figure, in this embodiment, a recess 50b is formed on the back surface 49b of the turntable 43b attached to the rotary shaft 26b of the rotor 25b. The armature 2 which is a part of the rotor 25b is provided inside the recess 50b.
7b is embedded and the armature 27b is integrated with the turntable 43b.

On the inner surface of the side plate 29b of the casing 23b, a pair of permanent magnets 22b as a stator are provided with an armature 27.
It is attached facing b. The armature 27b of this embodiment
Is composed of a coil having no core.

A commutator support member 36b is fixed to the center of the back surface 49b of the turntable 43b, and a commutator 35b is fixed to the outer peripheral surface of the commutator support member 36b. Bearing device 24, brush 40, brush holder 41,
The structure of the stopper ring 48 and other parts is the same as the first embodiment.
It is similar to the embodiment.

The casing 23b whose one end (upper end) is entirely open has the bottom plate 28 and the bottom plate 28, as in the first embodiment.
The bottom plate 28 is provided with a side plate 29b that is integral with the bottom plate 28, and a flange 31 that is integrally formed in the left-right direction so as to project from an open upper end edge 30 of the side plate 29b.

In the present embodiment, since the coil 27b serving as an armature is embedded in the turntable 43b, it is not necessary to separately secure a space for the armature inside the casing 23b, and the axial dimension of the casing 23b. Can be significantly shortened. Therefore, the total length of the motor can be shortened and the dimension H ₂ can be reduced. In addition,
The armature embedded in the turntable 43b may have a structure in which an armature winding is wound around a core.

(Fourth Embodiment) FIG. 7 is a front sectional view of a small motor 20c with a turntable according to a fourth embodiment of the present invention. The small motor in each of the above-described embodiments was a DC motor with a brush, but the small motor 20c in this embodiment is a brushless DC motor.

The casing 23c of the small motor 20c with a turntable is the casing 23b of the third embodiment.
It has almost the same structure as. The stator 22c is attached to the inside of the casing 23c.
Consists of an armature yoke fixed to the casing 23c and a plurality of armature coils attached to the armature yoke.

The rotating shaft 26c is rotatably supported by a bearing device 24 attached to the cylindrical protruding portion 37 of the casing 23c. Rotor 25c having rotating shaft 26c
Has a permanent magnet 27c facing the stator 22c. The permanent magnet 27c is formed of a ferrite magnet, a plastic neodymium magnet, or the like.

A turntable 43c is attached to the rotary shaft 26c, and the turntable 43c is composed of the casing 23.
A gap w is held between the open side upper edge 30 of c to cover the casing open portion 44c. The permanent magnet 27c has a recess 50 formed on the back surface 49c of the turntable 43c.
It is embedded inside c and integrated with the turntable 43c.

Each armature coil of the stator 22c includes rotor position detecting means such as a Hall element for detecting the rotation angle of the rotor 25c, and a semiconductor such as a transistor which performs a switching operation by a signal output from the detecting means. The energization timing is controlled by a commutation control circuit having an element, and a drive voltage is sequentially applied to excite. The permanent magnet 27c is attracted to the magnetic poles sequentially generated by the armature coil, so that the turntable 43c and the rotary shaft 26c rotate together with the permanent magnet 27c.

A turntable 43c is rotatably contacted on a washer 47c as a thrust support member provided on the upper end surface of the tubular member 45c of the bearing device 24. Therefore, the bearing device 24 is loaded with the load due to the own weight of the rotating shaft 26c, the turntable 43c and the permanent magnet 27c and its magnetic attraction force as a thrust load.
Therefore, in this embodiment, the total length of the motor can be shortened and the dimension H ₂ can be reduced.

(Fifth Embodiment) FIG. 8 is a casing 2 of a small motor with a turntable according to a fifth embodiment of the present invention.
It is a front sectional view of 3d. In each of the above-described embodiments, the motor mounting flange 31 is integrally formed on the casing opening portion side so as to form the same surface as the upper edge of the casing opening portion. However, in the casing 23d of this embodiment,
The flange 31d for mounting the motor is attached to the casing opening portion 4
It is formed at a lower position apart from the edge 30d on the fourth side.

For example, as shown in the figure, a flange 31d may be integrally formed so as to project outward from the side plate 29d, and this flange 31d may be attached to the device mounting plate 60 of the disc reproducing apparatus. With this configuration, the entire small motor with a turntable can be positioned above the device mounting plate 60.

The present invention can be applied to other small motors such as an AC motor in addition to the above-mentioned DC motor, and the disk rotated by the small motor with a turntable is an optical disk or an FD. It may be a magnetic disk such as a (flexible disk) or a hard disk, or another disk. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0051]

Since the present invention is constructed as described above, the total length of the motor can be greatly shortened and the risk of contact between the rotor and the casing can be eliminated.

[Brief description of drawings]

1 to 4 are views showing a first embodiment of the present invention, and FIG. 1 is a front sectional view of a small motor with a turntable.

FIG. 2 is an enlarged cross-sectional view showing a structure of a bearing device portion of a small motor with a turntable.

3 is a front view of the small motor with a turntable shown in FIG. 1. FIG.

FIG. 4 is a plan view of FIG.

FIG. 5 is a front sectional view of a small motor with a turntable according to a second embodiment of the present invention.

FIG. 6 is a front sectional view of a small motor with a turntable according to a third embodiment of the present invention.

FIG. 7 is a front sectional view of a small motor with a turntable according to a fourth embodiment of the present invention.

FIG. 8 is a front sectional view of a casing of a small motor with a turntable according to a fifth embodiment of the present invention.

FIG. 9 is a front sectional view of a conventional small motor with a turntable.

[Explanation of symbols]

20, 20a, 20b, 20c Small motor with turntable 22, 22b Permanent magnet (stator) 22c Stator 23, 23b, 23c, 23d Casing 24 Bearing device 25, 25b, 25c Rotor 26, 26b, 26c Rotating shaft 27 , 27b Armature 27c Permanent magnet 28 Casing bottom plate 30, 30d Open side upper edge (open side edge) 43, 43a, 43b, 43c Turntable 44, 44c Casing open part 45, 45c Cylindrical member 46 Cylindrical member Upper end surface 47, 47c Washer (thrust support member) 49, 49a, 49b, 49c Rear surface of turntable 50, 50b, 50c Recess w Gap

Claims (5)

[Claims] 1. A casing (23, 23b, 23c, 23d) whose one end is entirely opened, and a stator (22, 2) mounted inside the casing.
2b, 22c) and a bearing device (24) attached to the casing rotatably support a rotating shaft (26, 26b, 26c), and a rotor (25, 25b, 25) facing the stator.
c) and a turntable (4) which is attached to the rotary shaft and which holds a gap (w) between the open side edge (30, 30d) of the casing and covers the casing open portion (44, 44c).
3, 43a, 43b, 43c), and a small motor with a turntable. 2. The back surface of the turntable (49,49
A small motor with a turntable according to claim 1, characterized in that a concave portion (50, 50b) is formed in (a, 49b) and a part of the rotor is housed in the concave portion. 3. The small motor with a turntable according to claim 2, wherein an armature (27b) of the rotor is embedded in the recess (50b). 4. The recess (50c) is formed on the back surface (49c) of the turntable, and the permanent magnet (27c) of the rotor is embedded in the recess.
Small motor with turntable described. 5. A tubular member (45) fixed to a bottom plate (28) of a casing having a stator inside, while rotatably supporting a rotary shaft of a rotor having a turntable attached to the upper part thereof. , 45c) and a thrust support member (47, 4) provided on the upper end surface (46) of the tubular member and supporting the rotor in the thrust direction.
7c) and a bearing device for a small motor with a turntable.