JP2955757B2 - Disc type brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a disk-type brushless motor suitable for use in a disk-type single-phase brushless fan motor and the like, and in particular, a bearing requiring only one ball bearing. With this structure, a disk-type brushless motor that is inexpensive, requires a long service life, and requires high reliability can be configured.

[Prior art and its problems] Since brushless fan motors require reliability for tens of thousands of hours or more, a bearing structure as shown in Fig. 5 using two ball bearings is generally used. ing.

The bearing structure of FIG. 5 will be described.
A disk-shaped rotor (which is mainly composed of a magnet rotor or the like, but here, these are simply drawn in a disk shape for simplicity of the drawing and the description) 2 is attached to the upper part of the. .

The rotary shaft 1 is rotatably supported at its upper and lower ends by ball bearings 3 and 4 such as two ball bearings. The ball bearings 3 and 4 are mounted on both upper and lower open ends of a cylindrical bearing house 6 erected on the fixed portion 5. A spring 7 is interposed between the rotor 2 and the ball bearings 3 and 4 so that the ball bearing 3
Pressurized. Also, by the pressurization of the spring 7,
A retaining ring 8 is engaged with the rotating shaft 1 at the lower end of the ball bearing 4 in order to prevent the rotating shaft 1 from falling downward.

FIG. 6 shows another known bearing structure in which a spring 7 for applying a pressure is interposed between the ball bearings 3 and 4.

However, each of the bearing structures shown in FIGS. 5 and 6 requires two expensive ball bearings 3 and 4 and the ball bearings 3 and 4.
In addition, parts such as a spring 7 and a retaining ring 8 for applying pressure to the and / or 4 are required, and the man-hours for assembling these parts are large, thus increasing the cost of the brushless fan motor.

As an inexpensive bearing, a sliding bearing such as an oil-impregnated sintered metal (oil-less metal) bearing is known. However, if such a sliding bearing is used, a disk-type coreless single-phase brushless fan motor can be reduced in weight and weight. Although it is possible to reduce the thickness,
Radial loads due to eccentricity and the like are applied to the slide bearing, causing wear, resulting in short life and low reliability.

Therefore, in order to make the bearing structure inexpensive, an experiment was conducted in which one of the two ball bearings was replaced with an oil-impregnated sintered metal bearing that was a sliding bearing, but due to the eccentricity of the rotor, two ball bearings were used. Compared to the case of using, large abrasion occurred, which did not lead to long life, but had short life and low reliability.

This will be described with reference to FIG. 7. The bearing structure shown in FIG. 7 is obtained by replacing the ball bearing 3 at the upper part of FIG. 6 with an oil-impregnated sintered metal bearing 9 which is an inexpensive sliding bearing. ing.

According to the bearing structure shown in FIG. 7, the number of ball bearings is reduced by one, so that the cost is reduced.

However, in this bearing structure, since the center of gravity of the rotor 2 is applied to the oil-impregnated sintered metal bearing 9 as is apparent from the figure, the swing of the rotating shaft 1 is temporarily caused by the eccentricity of the rotor 2 or the like. Even if it can be held down, it is only for a short period, and the oil-impregnated sintered metal bearing 9 will wear.

As a result, even if only the ball bearing 4 provided at the lower end works effectively, since only one ball bearing 4 is used, a burden is imposed and the function of the original ball bearing cannot be fulfilled. Does not work as In addition, the ball bearing 4 at that position cannot suppress the swing of the rotating shaft 1 and the life of the ball bearing 4 is shortened, so that the ball bearing 4 cannot be used for a long period of time, and has high performance and long life. Was not expected. In addition, when the fan motor having the bearing structure is used, the ball bearing 4 is deteriorated, and the ball bearing 4 has a disadvantage that a large rattling sound is generated during rotation.

In this way, simply replacing one of the two ball bearings with an oil-impregnated sintered metal bearing to reduce the cost will maintain the same life and reliability as if two ball bearings were provided. Can not.

Therefore, the inventor of the present invention has set forth that in order to form a disk-type brushless motor at low cost, even if one ball bearing is used, the same bearing life and reliability as when two ball bearings are used can be ensured. A disk type single-phase brushless fan motor 10 having a structure as shown in FIG. 8 has been developed.

In this disk type single-phase brushless fan motor 10,
The rotating fan 11 is configured so that the center of gravity 12 of the rotating fan 11 is located above the bearing house 13, and a ball bearing 14 is provided above the bearing house 13, and the center of gravity 12 of the rotating fan 11 is mounted on the ball bearing 14. A sliding bearing 15 is provided at the lower end of the bearing house 13 to support the rotating shaft 16 rotatably.

The other parts of the fan motor 10 will be described in the embodiments of the present invention.
The same reference numerals are used and the description is omitted.

According to the disk-type single-phase brushless fan motor 10, the number of places where expensive ball bearings are used can be reduced from two to one, which is very useful.

In particular, in this case, it is possible to pressurize the ball bearing 14 by the magnetic attraction between the magnet rotor 17 and the stator yoke 18, and if this is used, the number of components required for pressurization can be reduced. There is also an effect that can be done.

Such a bearing structure is useful only for an axial gap type, that is, a diskless brushless motor having a coreless structure, and is used for a brushless fan motor including a radial gap type, that is, a brushless motor having a cylindrical structure. Cannot function effectively.

In the disk type single-phase brushless fan motor 10,
The reason why the reliability does not decrease even if the number of ball bearings used is reduced from two to one will be further described.

According to data studied and experimented by the inventor of the present invention, the force applied to the bearing of a motor employing a so-called direct drive system, such as a disk type brushless motor, is largely offset by the center of gravity of the rotor from the rotating shaft. Radial load.

Nevertheless, conventionally, as shown in FIG. 7, this point was neglected, so that long life and reliability could not be obtained.

In the above disk type single-phase brushless fan motor 10,
Since the center of gravity 12 of the rotor [rotating fan 11] is designed to be at the upper end of the bearing house 13, the point of action of the force applied to the bearing of the rotor 11 is the center of gravity of the rotor 11 It is.

Accordingly, by supporting the rotating shaft 16 with the ball bearing 14 provided at the upper end of the bearing house 13 including the center of gravity 12 of the rotor 11, most of the radial load can be supported by the ball bearing 14.

However, with this alone, it is difficult for the ball bearing 14 to completely suppress the swing of the rotating shaft 16.
A sliding bearing 15 is provided at a lower end portion of the bearing house 13 away from the shaft, so that the rotating shaft 16 does not tilt more than a predetermined angle.

When the direction of the rotating shaft 16 changes, a radial load is applied to the sliding bearing 15, but since such a phenomenon rarely occurs, there is almost no abrasion and no reduction in reliability is caused. Almost no.

In particular, in the case of a motor such as a disk-type single-phase brushless fan motor 10 that rotates only in one direction, the above-mentioned disadvantages are further reduced.

Thus, the disk-type single-phase brushless fan motor
In 10, the adoption of the ball bearings 14 and the sliding bearings 15 in a reasonable position not only reduces the cost as in the past, but also increases the effects in terms of service life and reliability. Obtainable.

The disk type single-phase brushless fan motor 10 configured as described above is very useful.

However, a need has arisen to further extend the life of the disk-type single-phase brushless fan motor 10.

In the bearing structure of the disk-type single-phase brushless fan motor 10, the sliding bearing 15 is the most worrisome in its life. As described above, the load is not applied to the slide bearing 15 so much that the service life can be extended.
When the fan motor 10 rotates stably when the fan 10 starts, for example, the rotating shaft 12 fluctuates, so that the rotating shaft 12 that is always in contact may slide and damage the bearing 15.

Further, since the rotating shaft 16 and the sliding bearing 15 are always in contact, noise is generated by the contact.

[Problems of the Invention] The present invention has been made to solve the above-mentioned drawbacks of a motor having a bearing structure as shown in FIG. 8, and the sliding bearing is significantly worn or damaged due to wobble of the rotating shaft. The purpose of this method is to eliminate the need for a long-life, low-cost construction of the bearing structure, and to reduce noise. The sliding bearing may be used. An object of the present invention is to make it possible to use a member.

[Means for Achieving the Object of the Present Invention] The present invention provides a magnet rotor having N and S magnetic poles, and a stator armature on a fixed side having a stator yoke with an axial gap therebetween. In a disk-type brushless motor in which a rotating shaft that rotates integrally with the magnet rotor is rotatably supported by a bearing provided in a bearing house, a center of gravity of a rotor including the magnet rotor is positioned above the bearing house. The above-mentioned rotor is constructed, a ball bearing is provided on the upper part of the bearing house, and the center of gravity of the rotor is supported by the ball bearing. The bearing house facing the lower end of the bearing house is provided with a sliding bearing or a suitable resin. This is achieved by mounting a tilt angle restricting member for restricting the rotation shaft formed in the above from falling over a predetermined angle in the radial direction through a minute gap in the radial direction with the rotation shaft. That.

Another object of the present invention is to make the length of the minute gap in the radial direction between the rotating shaft and the tilt angle regulating member shorter than the gap length in the axial direction between the magnet rotor and the stator. Can be achieved by:

[Effect of the Invention] In the disk type single-phase brushless fan motor 19 to which the present invention is applied, since the minute gap 21 in the radial direction is formed between the inclination angle regulating member 20 of the rotating shaft 16 and the rotating shaft 16, the motor 19 During rotation of the rotor, the center of gravity 12 of the rotating fan [rotor] 11 is
Since the ball bearing 14 is used, stable rotation can be performed without damaging the ball bearing 14 and shortening the life of the ball bearing 14.

Also, only when the rotating shaft 16 fluctuates, such as when the motor 19 starts, the tilt angle regulating member 20 and the rotating shaft 16 only come into contact.
When the motor 19 is rotating stably, a radial gap is provided to prevent the armature coil 23 from being damaged due to the contact between the rotor 11 and the coreless stator armature [stator] 22. Since the rotating shaft 16 and the tilt angle restricting member 20 are separated from each other by the length of the gap 39 in the axial direction between the magnet rotor 17 and the armature coil 23 and are not always in contact with each other,
The life of the tilt angle regulating member 20 is not shortened.

As described above, in the present invention, even if the number of ball bearings 14 used is reduced from two to one, the reliability does not decrease.

That is, in the present invention, the point of action of the force applied to the ball bearing 14 of the disk-type single-phase brushless fan motor 19 is the center of gravity 12 of the rotor 11.

Therefore, by providing the ball bearing 14 at the center of gravity 12 of the rotor 11, most of the radial load can be received by this.

However, if only this is done, it is difficult for the ball bearing 14 to completely suppress the swing of the rotating shaft 16, so that the motor 19 rotates stably, and even if only one ball bearing 14 is used, the rotating shaft 16 can be accurately rotated.
Of the rotating shaft 16 that restricts the rotating shaft 16 from tilting at an angle greater than a predetermined angle until the rotating shaft 16 is supported.
Is mounted on the bearing house 13 at a position distant from the ball bearing 14 and radially apart from the rotating shaft 16 by the length of the minute gap 21 in the radial direction.

Rotary shaft made of suitable material such as sliding bearing or resin
When the direction of the rotating shaft 16 changes, a radial load is applied to the tilt angle restricting member 20 of 16, but it is not always in contact with the rotating shaft 16, and such a case is rare. Therefore, wear hardly occurs, and there is almost no reduction in reliability.

Of course, in the present invention, since the magnet rotor 17 and the stator yoke 18 are magnetically attracted and hold each other, no spring or the like for applying pressure is required, and the ball bearing is not required.
14 can be preloaded.

As described above, according to the present invention, the ball bearing 14 and the tilt angle restricting member 20 of the rotary shaft 16 are employed at a reasonable position, and the tilt angle restricting member 20 and the rotary shaft 16 are connected to the minute gap 21 in the radial direction. As compared with the conventional motor 10 using one ball bearing 14 and one sliding bearing 15 shown in FIG. Obtainable.

[Embodiment of the present invention] Fig. 1 is an exploded perspective view of a disk type single-phase brushless fan motor 19 showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional view of the fan motor 19, Figs. FIG. 4 is an explanatory view of a bearing, and an embodiment of the present invention will be described below with reference to FIGS.

A square disk-type single-phase brushless [axial flow] fan motor 19 with a thin axial thickness has a coreless structure air-gap single-phase brushless having a venturi case 24 serving as a stator and a rotating fan 11 serving as a rotor. It is an axial fan motor.

In the fan motor 19, a motor housing 26 connected to a stay 25 formed to extend radially inward of the inner circumference of a venturi case 24 having a recess therein is integrally formed at the center thereof. As a result, the rotating blades of the rotating fan 11 are mounted on the outer periphery of the motor housing 26 at the bottom of the venturi case 24.
A flowing wind passage hole 28 is formed for passing the wind that is winded by the wind 27 in the axial direction.

A bearing house 13 extending in the axial direction is integrally formed at the center of the motor housing 26, and a ball bearing 14 and a tilt angle restricting member 20 for the rotary shaft 16 made of a sliding bearing or resin are mounted on the bearing house 13. In addition, the rotating shaft 16 fixed to the rotating fan 11 is rotatably supported on the rotating shaft 16 so that the rotating fan 11 can rotate. Further, the motor housing 26 is integrally formed with a column 29 extending upward in the axial direction at a position symmetrical with respect to 180 degrees. A coreless stator armature 22 is disposed on the support 29, and a screw 30 made of a magnetic material is formed in the stator yoke 18 through holes.
The stator armature 22 is disposed and fixed by being screwed into a screw hole 34 at the top of the column 29 through a through hole 33 formed in the printed circuit board 31 and 31.

In fixing the stator armature 22 to the upper part of the column 29, the stator 30 is passed through the stator yoke 18 and the printed circuit board 32 such that the screw 30 is located at a desired position where the single-phase single-phase flashless fan motor 19 can be started by itself. The holes 31 and 33 need to be formed.

An adhesive 35 such as a double-sided adhesive tape is provided on the upper surface of the stator yoke 18 as shown in FIG.
Two air-core type armature coils 23 are disposed symmetrically with respect to 180 degrees. In addition to the through holes 31, the position detecting element housing holes 36 (see FIG. 2) are formed in the stator yoke 18 at positions facing the effective conductors extending in the radial direction of the armature coil 23. Position sensing element arranged on the upper surface of 32
37 [See Fig. 2]. On the lower surface of the printed circuit board 32, two energization control circuit ICs 38 are provided, and lead wires 41 are electrically connected and fixed. Note that the energization control circuit IC 38 in this embodiment may be formed as a single IC, but the IC 38 is designed to be diverted to another motor.
It is divided into two parts. Position sensing element 37 on top
The printed circuit board 32 on which the power control circuit IC 38 is disposed on the lower surface is fixed with an adhesive to the lower surface of the stator yoke 18 on which two armature coils 23 are disposed on the upper surface. An armature 22 is formed, and is opposed to a four-pole flat magnet rotor 17 having N-pole and S-pole permanent magnets fixed to the rotating fan 11 through an axial gap 39 so as to rotate relatively. Let me.

The rotating fan 11 is designed and configured such that the center of gravity 12 is located above the bearing house 13. Accordingly, a ball bearing 14 is provided above the bearing house 13 to support the center of gravity 12 of the rotary fan 11 with the ball bearing 14. At the position of the bearing house 13 facing the lower end of the bearing house 13, a sliding bearing or resin is provided. For example, a tilt angle regulating member 20 for restricting the rotation shaft 16 formed of an appropriate material from falling over a predetermined angle in the radial direction is used as the rotation shaft 16.
And a small gap 21 in the radial direction.

Referring to FIGS. 3 and 4, a small minute gap 21 in the radial direction between the rotating shaft 16 of the tilt angle regulating member 20 for restricting the rotating shaft 16 from falling more than a predetermined angle in the radial direction. To explain the length, the radial length of the minute gap 21 is l ′, and the gap between the magnet rotor 17 and the armature coil 23 is
Assuming that the length in the axial direction of 39 is l, unless l> l ', as is apparent from FIGS. 3 and 4, the rotation of the rotating fan 11 is stable until it becomes stable. Since the shaft 16 fluctuates and tilts, the magnet rotor 17 and the armature coil 23
May come into contact with each other and the armature coil 23 may be damaged.

Therefore, the minute gap 21 has a length l 'in the radial direction.
Is designed to have a length such that l ′ <l.

For this reason, the ball bearing 14 receives most of the load generated by the eccentricity of the rotating fan 11, so that when the rotating fan 11 starts rotating stably, the rotating shaft 16 is stably supported by the ball bearing 14 alone. be able to.

Until the rotating fan 11 is stabilized, the ball bearing 14
It is difficult to completely suppress the swing of the rotating shaft 16 by using only the above. Therefore, the tilting angle restricting member 20 is provided at the lower end opening of the bearing house 13 away from the ball bearing 14, and the tilting motion of the rotating shaft 16 is generated. Only the load can be received with this.

In addition, a retaining ring 40 is engaged with the rotation shaft 16 at a lower portion of the falling angle regulating member 20 with a slight distance.

Note that a radial load is generated due to magnetic attraction between the magnet rotor 17 and the stator yoke 18.

This is particularly large in the case of the disk type single-phase brushless fan motor 19 of this embodiment. In the bearing structure according to the present invention, the radial load effectively acts as a pressurizing force on the ball bearing 14, so that a spring or the like for performing pressurizing is not required. So that you don't have to.

Although a retaining ring 40 is provided to prevent the rotating fan 14 from coming off, unlike the conventional bearing structure, no force is applied to the retaining ring 40 in normal times, so a simple and inexpensive plastic ring or the like is used. Can be used, and in terms of cost,
It is also advantageous in assembly.

[Effects of the Invention] As described in detail above, according to the present invention, the number of expensive ball bearings to be used is reduced from two to one without deteriorating reliability, and the tilt angle regulating member is a rotor. It only acts to prevent contact between the rotor and the stator, and does not always contact the rotating shaft, so that its life can be formed very long.

In addition, the number of components required for pressurization can be reduced, and the number of assembly steps can be reduced, so that a highly reliable disk-type brushless motor can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a disk-type single-phase brushless fan motor showing one embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the fan motor, FIG. 3 and FIG.
5 to 8 are explanatory views of a conventional bearing structure. 1 ... rotating shaft, 2 ... rotor, 3, 4 ... ball bearing, 5 ... fixed part, 6 ... bearing house, 7 ... spring, 8 ... retaining ring, 9 ...
... oil-impregnated sintered metal bearings, 10 ... disk type single-phase brushless fan motor, 11 ... rotating fan, 12 ... center of gravity, 13 ... bearing house, 14 ... ball bearings, 15 ... sliding bearings, 16 ... Axis of rotation,
17 …… Magnet rotor, 18 …… Stator yoke, 19 ……
Disc-type single-phase brushless fan motor, 20 ... Rotating shaft tilt angle regulating member, 21 ... Microscopic air gap, 22 ... Coreless stator armature, 23 ... Armature coil, 24 ... Venturi case, 25 …… Stay, 26 …… Motor storage part, 27 ……
Rotating blades, 28 …… Flowing air passage holes, 29 …… Posts, 30 …… Screws, 31
…… Transparent hole, 32 …… Printed circuit board, 33 …… Transparent hole, 34 …… Screw hole, 35 …… Adhesive material, 36 …… Position sensing element storage hole, 37 …… Position sensing element, 38 …… Electrification control Circuit IC, 39 …… Axial gap, 40 …… Retaining ring, 41 …… Lead wire.

Claims (1)

(57) [Claims] A magnet rotor having magnetic poles of N and S poles is provided, and a stator armature is provided on a fixed side having a stator yoke via an air gap with the magnet rotor, and is integrated with the magnet rotor. A disk-type brushless motor in which a rotating shaft is rotatably supported by a bearing provided in a bearing house, wherein the rotor is configured such that the center of gravity of the rotor including the magnet rotor is positioned above the bearing house. In a disk-type brushless motor in which a ball bearing is provided on the upper part of the bearing house and the center of gravity of the rotor is supported by a ball bearing, the bearing house facing the lower end of the bearing house is provided with a sliding bearing or an appropriate resin. A tilt angle restricting member for restricting the rotating shaft from falling more than a predetermined angle in the radial direction is attached to the rotating shaft via a small gap in the radial direction. The length of the minute gap in the radial direction between the rotating shaft and the tilting angle limiting member is made shorter than the gap length in the axial direction between the magnet rotor and the stator, before the rotor is fixed and contacted. A disc-type brushless motor, wherein a rotation axis can be restricted by the inclination angle regulating member.