JPH08275431A - Motor - Google Patents

Abstract

PURPOSE: To eliminate the restriction for selecting the material of a retention part and to reduce cost by providing a retention part for retaining a bearing for supporting a rotor shaft at a motor chassis and fixing an attraction magnet to the motor shaft and directly attracting a rotor side. CONSTITUTION: The other half part side 28b of a rotor shaft 28 where one edge part side 28a is forced in an fixed to a boss 27 of a rotor 29 is inserted into an oil impregnated sintered bearing 32 of a bearing support mechanism 30 at the side of a motor chassis(MS) 21. As a result, the rotor 29 is directly and magnetically attracted by an attraction magnet 34 at a magnetic attraction part 24a of a lower yoke plate 24 and the entire rotor 29 deflects to the bottom side of MS 21. The rotor shaft 28 is supported while the end face of the other half part side 28b is in contact with a thrust pad 33. Also, the attraction magnet 34 is located inn a recessed-step-shaped magnetic pole attraction part 24a of the lower yoke plate 24 of the rotor 29 while it is engaged and inserted, opposes the magnetic attraction part 24a with a required space between them and they are attracted each other and then a stator substrate 22 is engaged and retained at a specific position of the circumferential part of the MS 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor such as a flat brushless motor.

[0002]

2. Description of the Related Art In a conventional flat brushless motor, as shown in FIG. 5, a stator substrate 2 engaged and held by a motor chassis 1 is fixed by rotor magnets 5, 6 fixed to yoke plates 3, 4 from both sides. The yoke plates 3 and 4 are sandwiched at a predetermined interval and, in this state, the boss 7 is formed at the center thereof.
And one end side 8a of the rotor shaft 8 is press-fitted and fixed to the center of the boss 7 to form the rotor 9.

On the other hand, the motor chassis 1 is provided with a bearing support mechanism 10 for rotatably supporting the rotor shaft 8. The bearing support mechanism 10 rotatably supports the other half portion 8b of the rotor shaft 8 and the stator substrate 2. Is engaged and held on the peripheral portion of the motor chassis 1, and the rotor 9 is rotated by the vertical magnetic flux generated from the rotor magnets 5 and 6 with respect to the stator substrate 2.

In the conventional flat brushless motor constructed as described above, the bearing support mechanism 10 has the cylindrical oil-impregnated bearing 12 press-fitted into the cylindrical portion 11b of the bearing housing 11 having the cylindrical flange portion 11a on the base end side. This bearing support mechanism is configured such that a thrust receiver 13 formed of a wear-resistant resin such as nylon is fixed to the outer end surface side of the flange portion 11a in the axial direction of the cylindrical portion 11b by caulking. 10 is fixed to the center of the motor chassis 1 by caulking, the rotor shaft 8 is inserted into the sintered oil-impregnated bearing 12 on the other half side 8b, and the end surface of the rotor shaft 8 is thrust-received.
It is designed to be in contact with the shaft 3 for axial support.

In this flat brushless motor, the rotor 9 is prevented from floating above the motor chassis 1, that is, the rotor shaft 8 is prevented from moving in a direction opposite to the direction of the thrust shaft support, and a stable rotation is ensured by a magnet. It is configured as a so-called rotor attraction magnet system in which the chassis 1 side and the rotor 9 side are attracted to each other. Therefore, the bearing housing 11 is made of a magnetic metal material such as iron,
A ring-shaped attraction magnet 14 is fitted and fixed to the inner peripheral portion of the boss 7 formed of a metal such as brass so as to correspond to the flange portion 11a of the bearing housing 11, and the attraction magnet 14 and the flange of the bearing housing 11 are fixed. Part 11
The rotor 9 is biased toward the motor chassis 1 by applying a magnetic attraction force between the rotor 9 and a, that is, the rotor shaft 8 is brought into contact with the thrust receiver 13 and is axially supported in the thrust direction.

In the flat brushless motor shown in the figure, a motor cover 15 for protecting the rotor 9 is fitted on the release surface side of the motor chassis 1, and a pulley 16 is attached to the outer end of the boss 7. It is provided integrally.

[0007]

As described above, in the conventional flat brushless motor shown in FIG. 5, the attraction magnet, which is separate from the rotor magnet, is fixed to the rotor side, and is formed of magnetic metal fixed to the motor chassis. A magnetic attraction force is applied between the bearing housing and the flange to attract the rotor to the motor chassis side to prevent the rotor from floating above the motor chassis. Since it is a so-called rotor attraction magnet method that does not affect the rotor, it has a low rotor no-load rotation loss and is suitable as a low power consumption motor, but the attraction magnet is formed of a magnetic metal separate from the motor chassis. However, there is a problem in that the cost is high because the device is sucked in.
In other words, the sintered oil-impregnated bearing used as a motor bearing has a sufficient strength because the sintered density decreases and the strength against impact load decreases when trying to secure a sufficient oil content in order to improve the performance. After being press-fitted and held in a precision bearing housing, the bearing housing was caulked and joined to the motor chassis at a flange portion at the base end thereof.

On the other hand, since the attraction magnet fixed to the rotor side needs to be attracted to the flange portion of the bearing housing due to space limitation, the bearing housing is made of magnetic metal which is more expensive than non-magnetic brass. The cost of the bearing housing itself is high, and the cost of caulking work for fixing the bearing housing to the motor chassis is an obstacle to cost reduction of the entire motor.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a motor in which there is no restriction on selection of a material for a holding portion that holds a bearing of a motor chassis and a rotor, and cost can be reduced. To aim.

[0010]

In order to achieve the above object, a motor according to the present invention is provided in a motor chassis,
A cylindrical holding portion that holds the bearing of the rotor shaft of the rotor, an attraction magnet that is fixed to the motor chassis and directly attracts the rotor, and a magnetic attraction portion that is formed on the rotor side and that corresponds to the attraction magnet with a required gap. It is configured by including.

[0011]

With this structure, the bearing of the rotor shaft is fixedly held by the cylindrical holding portion provided on the motor chassis, the bearing mechanism of the rotor shaft is integrated with the motor chassis, and the rotor is magnetic. The attraction magnet directly attracts the motor chassis by the attraction magnet to stably support the rotor shaft in the thrust direction, thereby preventing the motor shaft from floating.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4, and one embodiment will be described with reference to FIGS.

The brushless motor of this embodiment is also composed of a stator and a rotor, like the conventional flat brushless motor shown in FIG. That is, the stator substrate 22 having a printed coil as a stator coil fixed to the motor chassis 21 is sandwiched from both sides by the rotor magnets 25 and 26 fixed to the yoke plates 23 and 24 at predetermined intervals. Yoke plates 23, 2
4 is fixed to the boss 27 at the center thereof, and one end side 28a of the rotor shaft 28 is press-fitted and fixed to the center of the boss 27 to form the rotor 29.

In the present embodiment, the central portion of the lower yoke plate 24, which faces the motor chassis 21 of the rotor 29,
That is, the magnetic attraction portion 24a is formed by forming the part surface fixed to the boss 27 inwardly into a concave step shape by step drawing. Further, in this example, the bearing support mechanism 3 of the rotor 29 is used.
0 is provided integrally with the motor chassis 21. That is, a cylindrical bearing housing portion 31 as a holding portion for holding the bearing is integrally formed by rising at the center of the bottom surface of the motor chassis 21 made of magnetic metal by deep drawing.
Due to the deep drawing of the bearing housing portion 31, the outer peripheral surface portion surrounding the cylindrical mouth portion 31a at the lower end of the bearing housing portion 31 has a concave surface portion 31b on the lower surface side of the bottom portion of the motor chassis 21.
Is formed as.

In this way, the sintered oil-impregnated bearing 32 is press-fitted and fixed from the upper end side to the bearing housing portion 31 integrally formed in the motor chassis 21 by deep drawing, and the cylindrical mouth portion 31a at the lower end of the bearing housing portion 31 is formed. A thrust receiver 33 made of a wear-resistant material such as nylon is fitted to and brought into contact with the lower end surface of the sintered oil-impregnated bearing 32. In this state, the thrust support plate 33a is fixed to the concave portion 31b on the lower surface side of the motor chassis 21 by welding or adhesion to hold the thrust receiver 33, thereby forming the bearing support mechanism 30.

A ring-shaped attraction magnet 34 is fixed to the inner surface of the bottom of the motor chassis 21 so as to surround the base of the bearing housing portion 31 of the bearing support mechanism 30, and to the magnetic attraction portion 24a of the lower yoke plate 24 described above. It is adapted.

When the bearing housing portion 31 is integrated with the motor chassis 21 made of a magnetic material as described above, the ring-shaped attraction magnet 34 is fitted into the bearing housing portion 31 to be attached to the motor chassis 21. Magnetically adsorbed and fixed without the use of adhesives,
The bearing housing portion 31 forms a magnetic path,
The magnetic force can be effectively used, and the suction is more securely fixed. When the motor chassis 21 is made of a non-magnetic material, the attraction magnet 34 is attached to the bearing housing portion 3.
It is fixed by press fitting or adhering to the motor chassis 21 on the outer periphery of the base portion of 1.

Thus, the motor chassis 21 and the rotor 2 are
9 and by inserting the other half side 28b of the rotor shaft 28 whose one end side 28a is press-fitted into the boss 27 of the rotor 29 into the sintered oil-impregnated bearing 32 of the bearing support mechanism 30 on the motor chassis 21 side. , The rotor 29 is directly magnetically attracted by the attraction magnet 34 in the magnetic attraction portion 24a of the lower yoke plate 24 so that the entire rotor 29 is biased toward the bottom side of the motor chassis 21, and the rotor shaft 28 is thrust at the end surface on the other half side 28b. The attraction magnet 34 is axially supported in a state of being in contact with the receiver 33, and the attraction magnet 34 is located in the recessed magnetic attraction portion 24a of the lower yoke plate 24 of the rotor 29 in a fitted state. Are placed facing each other and attracted to each other, and the stator substrate 22 is attached to the motor chassis 2
It is engaged and held at a predetermined position on the peripheral edge portion of 1. After the motor chassis 21 and the rotor 29 are combined in this way, a brushless motor is configured by fitting a motor cover 35 that protects the rotor 29 on the open surface side of the motor chassis 21. Also in this example, the pulley 36 is integrally provided on the outer end portion of the boss 27.

As described above, in the flat brushless motor of this embodiment, the bearing housing portion 31 for holding the sintered oil-impregnated bearing 32 that supports the rotor shaft 28 is integrally formed on the motor chassis 21 by deep drawing. Then, the attraction magnet 34 is fixed to the inner surface of the bottom portion of the motor chassis 21 on the outer peripheral side of the base end of the bearing housing portion 31, and the attraction magnet 34 and the magnetic attraction portion 24a of the lower yoke plate 24 of the rotor 29 are magnetically attracted directly. Since the rotor 29 is configured to be biased to the bottom side of the motor chassis 21, the bearing housing is formed of magnetic metal separately from the motor chassis, and the conventional flat magnet configured to attract the attraction magnet fixed to the rotor side. Compared to brushless motors, there are no restrictions on material selection for the motor chassis and bearing housing itself. The cost of parts and processing costs are reduced,
Further, the fixing work such as caulking to the motor chassis becomes unnecessary, and the cost can be reduced.

Further, since the attraction magnet 34 is located in the recessed magnetic attraction portion 24a of the lower yoke plate 24 of the rotor 29 in a fitted state, a space between the motor chassis 21 and the rotor 29 can be gained. As a result, a thin motor can be constructed.

Further, the bearing housing portion 31 is formed integrally with the motor chassis 21 so that it can be formed in a regular position with high dimensional accuracy, and the attraction magnet 34 and the motor chassis 21 are directly magnetically attracted to the rotor 29. It can be surely biased to the bottom side of the motor chassis 21, the rotor shaft 28 can be pivotally supported in the thrust direction with high accuracy, and the rotor 29 can be stably rotated.

FIG. 3 shows another embodiment of the motor according to the present invention.

This embodiment is an improvement of the bearing support mechanism, especially the bearing housing portion in the embodiment shown in FIGS. 1 and 2, and since the other members are configured the same, the same members are designated by the same reference numerals. And the description is omitted.

Also in this example, the bearing support mechanism 40 of the rotor 29 is integrally provided on the motor chassis 21, and a cylindrical bearing housing portion 41 is integrally formed in the central portion of the bottom surface of the motor chassis 21 by deep drawing. It was done. By deep drawing the bearing housing portion 41, the bearing housing portion 4 is formed on the bottom surface of the bottom of the motor chassis 21.
The outer peripheral surface portion surrounding the cylindrical mouth portion 41a at the lower end as the hollow base end portion of 1 is formed as a concave surface portion 41b.

The bearing housing portion 41 is formed on the surface surrounding the bearing housing portion 41, that is, the concave surface portion 41b.
A plurality of support pieces 41c that can be folded back toward the lower end cylindrical mouth 41a side are formed in a radial shape from the base end peripheral edge of the bearing housing 41 in the radial direction. This support piece 4
By folding back 1c to the lower end cylindrical mouth portion 41a side of the bearing housing portion 41, an opening portion 41d is formed in the concave surface portion 41b.

As described above, the sintered oil-impregnated bearing 32 is press-fitted and fixed from the upper end opening side to the bearing housing portion 41 integrally formed in the motor chassis 21 by deep drawing, and the cylindrical opening portion at the lower end of the bearing housing portion 41 is formed. Thrust receiver 33 formed from 41a by a wear resistant material such as nylon
To contact the lower end surface of the sintered oil-impregnated bearing 32, and in this state, the supporting piece 41c is folded back to the cylindrical mouth portion 41a side of the lower end of the bearing housing portion 41 to hold the thrust receiver 33, thereby supporting the bearing. The mechanism 40 is configured.

The inner surface of the bottom of the motor chassis 21 is surrounded by the base of the bearing housing 41 of the bearing support mechanism 40.
That is, the ring-shaped attraction magnet 34 is fixed to the inner surface side of the concave portion 41b so as to correspond to the magnetic attraction portion 24a of the lower yoke plate 24 of the rotor 29 as in the above-described embodiment.

In this example, the bearing housing portion 41 is integral with the motor chassis 21, so the motor chassis 2
By forming 1 from a magnetic metal, the ring-shaped attraction magnet 34 is magnetically attracted to the motor chassis 21 and fixed without using an adhesive or the like, and the bearing housing portion 41 forms a magnetic path. The magnetic force can be effectively utilized, and it is more securely attracted and fixed.

When the motor chassis 21 is made of a non-magnetic material, the attraction magnet 34 is press-fitted into the outer periphery of the base of the bearing housing portion 41 or the inner surface side of the concave surface portion 41b surrounding the bearing housing portion 41 in the motor chassis 21. Adhesively fixed with adhesive. In the case of the adhesive fixing using the adhesive, the adhesive can be adhered without sticking out to the inner surface side of the motor chassis 21 by adhering the adhesive while cutting and raising the support piece 41c and filling the opening 41d.

In this way, the ring-shaped attraction magnet 34
Is fixed to the inner surface of the bottom portion of the motor chassis 21, that is, the inner surface side of the concave surface portion 41b surrounding the bearing housing portion 41, so that the cut-raised opening 41d of the support piece 41c is closed. By filling the opening 41d with the adhesive as described above, the opening 41d can be more reliably closed.

The motor chassis 21 thus constructed
The sintered oil-impregnated bearing 32 on the bearing support mechanism 40 side of the rotor 2
By inserting the other half portion side 28b of the rotor shaft 28, which is press-fitted and fixed at one end portion side 28a, into the boss 27 on the 9 side, the rotor 29 causes the magnetic attraction portion 2 of the lower yoke plate 24 to move.
4a, the entire magnets 29 are magnetically attracted by the attraction magnets 34 to bias the entire rotor 29 to the bottom side of the motor chassis 21, and the rotor shaft 28 is axially supported with the end surface of the other half side 28b abutting the thrust receiver 33. At the same time, the stator substrate 22 is engaged and held at a required position on the peripheral portion of the motor chassis 21. In this state, the attraction magnets 34 are located in the recessed magnetic attraction portions 24a of the lower yoke plate 24 of the rotor 29 in a fitted state, and face each other with a required gap therebetween to be attracted to each other. A motor cover 35 that protects the rotor 29 is fitted to the open surface side of the motor chassis 21 to form a flat brushless motor.
Also in this example, the pulley 3 is attached to the outer end of the boss 27.
6 are integrally provided.

In the flat brushless motor of the present embodiment constructed as described above, the bearing housing portion 41 for holding the sintered oil-impregnated bearing 32 for supporting the rotor shaft 28 and fixing it to the motor chassis 21 is the motor chassis. The thrust receiver 3 which is integrally formed by deep drawing on 21 and is fitted into the lower end cylindrical mouth portion 41a of the bearing housing portion 41.
Since the supporting piece 41c for holding 3 is formed in a cut-and-raised shape on the motor chassis 21, the parts cost and processing cost of the bearing housing and the support member itself of the thrust receiver are reduced, and the fixing work by caulking or the like to the motor chassis. In addition, the thrust receiver 33 is not required to be held, and the supporting piece 41c is simply folded back to the lower end cylindrical mouth portion 41a side of the bearing housing portion 41 to eliminate the need for fixing work by caulking or the like, which enables cost reduction. . Also in the case of this example, the bearing housing portion 41 can be formed in the regular position with high dimensional accuracy by being integrally formed with the motor chassis 21, and the attraction magnet 34 and the motor chassis 21 can be directly magnetically attracted to each other, so that the rotor 29 can be surely biased to the bottom side of the motor chassis 21, and the rotor shaft 28
The shaft can be supported with high accuracy in the thrust direction and can be stably rotated.

Further, since the ring-shaped attracting magnet 34 is correspondingly closed from the inner surface side of the opening 41d formed by cutting and raising the supporting piece 41c in the motor chassis 21, the inside of the motor chassis 21 has a sealed structure. Therefore, foreign matter such as dust is prevented from entering, and there is no possibility that the rotation of the rotor 29 is hindered particularly by the intrusion of magnetic powder and the reliability is not impaired.

Further, FIG. 4 shows a bearing support mechanism of still another embodiment.

In the bearing support mechanism 50 of this embodiment, the bearing housing portion 51 for fixing and holding the sintered oil-impregnated bearing 32 is integrally formed in the motor chassis 21 in a cylindrical shape by deep drawing, as in the above-described embodiments. A support piece 51c that supports a thrust receiver 33 that fits into a cylindrical mouth portion 51a at the lower end as a hollow base end portion of the bearing housing portion 51 is provided on the peripheral surface of the bearing housing portion 51 at a required interval in the circumferential direction from the base end. The support piece 51c is bent in the direction of the cylindrical opening 51a at the lower end of the bearing housing portion 51 to form an opening 5 on the peripheral surface of the base of the bearing housing portion 41.
1d is formed. Thus, the support piece 51c is bent in a direction orthogonal to the axial direction so as to close the mouth end of the cylindrical mouth portion 51a, and in this state, the thrust receiver 33 is inserted from the upper end mouth portion of the bearing housing portion 51. After being supported by the support piece 51c, the sintered oil-impregnated bearing 32 is press-fitted and fixed to the bearing housing portion 51 to form the bearing support mechanism 50 that pivotally supports the rotor shaft 28. In FIG. 4, 51
Reference numeral b denotes a thin concave surface portion formed by drawing the bearing housing portion 51.

The inner surface of the bottom of the motor chassis 21 is surrounded by the base of the bearing housing 51 of the bearing support mechanism 50.
That is, the ring-shaped attracting magnet 34 is fixed to the inner surface side of the concave portion 51b so as to correspond to the magnetic attracting portion (not shown) of the lower yoke plate of the rotor as in the above-described embodiments.

In the bearing support mechanism 50 of the present embodiment constructed as described above, the opening that opens to the peripheral surface of the bearing housing portion 51 after the support piece 51c that supports the thrust receiver 33 is cut and raised and bent is the bearing. It is blocked by the outer peripheral surface of 32, the thrust receiver 33, and the inner peripheral surface of the attraction magnet 34 to prevent dust and the like from entering the motor chassis 21.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the present invention.

For example, the magnetic attraction portion on the rotor side can be directly formed on the boss by forming the boss from a magnetic material.

In the brushless motor of this embodiment, the rotor magnet is arranged on both sides of the stator substrate to generate a vertical magnetic flux. However, the rotor magnet is arranged on one side of the stator substrate, that is, the stator. It may be configured to correspond only to the coil surface side.

Further, the stator coil of the stator substrate is not limited to the printed coil, and a coil formed by a winding may be used.

Further, without forming a pulley on the boss, the rotor shaft can be extended and another rotating member can be axially attached.

The present invention can be applied not only to the flat brushless motor but also to a motor having a thickness in the axial direction, and the bearing support mechanism is limited to the axial support of the rotor shaft of the motor. Instead, it can be applied to the pivotal support of the shaft of another rotating device.

[0044]

As described above, according to the present invention, the motor chassis is provided with the holding portion for holding the bearing that supports the rotor shaft, and the magnet is fixed to the motor chassis so that the rotor side is directly attracted. Since it is configured, the bearing housing is formed of magnetic metal separately from the motor chassis, and compared with the conventional motor in which the rotor is biased to the motor chassis side by the attraction magnet through this bearing housing, There is no restriction on material selection and the cost of parts and processing cost can be reduced and the cost of the entire motor can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a brushless motor to which the present invention is applied.

FIG. 2 is an exploded perspective view of the brushless motor shown in FIG.

FIG. 3 is a sectional view of another embodiment of the brushless motor to which the present invention is applied.

FIG. 4 is a perspective view of another embodiment of the motor bearing mechanism according to the present invention.

FIG. 5 is a sectional view of a conventional flat brushless motor.

[Explanation of symbols]

 21 motor chassis 22 stator substrate 24 yoke plate 24a magnetic attraction portion 27 boss 28 rotor shaft 29 rotors 31, 41, 51 bearing housing portion as a holding portion 32 bearing 33 thrust receiving 34 attraction magnet

Claims (5)

[Claims] 1. A cylindrical holding portion provided on a motor chassis for holding a bearing of a rotor shaft of a rotor, an attraction magnet fixed to the motor chassis for directly attracting the rotor, and formed on the rotor side. And a magnetic attraction portion corresponding to the attraction magnet with a required gap. 2. The motor according to claim 1, wherein the magnetic attraction portion is formed on the yoke plate of the rotor so as to correspond to the attraction magnet. 3. The motor according to claim 1, wherein the magnetic attraction portion is formed on the yoke plate of the rotor in a concave step shape corresponding to the attraction magnet. 4. The motor according to claim 1, wherein the attraction magnet is surrounded and fixed to a base portion of the holding portion so as to correspond to the magnetic attraction portion on the rotor side. 5. The thrust holding member of the rotor shaft is formed by integrally forming the cylindrical holding portion on the motor chassis by drawing, and folding the holding portion back to a base end opening side of the holding portion on a surface surrounding the holding portion. A support piece for supporting the support piece is formed in a cut and raised shape, and the attraction magnet is fixed to the base portion of the holding portion so as to surround the support piece so as to close the cut and raised portion of the support piece. The motor according to Item 1.