KR910004538B1 - Fan motor - Google Patents

Abstract

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Description

Fan motor

1 is a cross-sectional view of a fan motor in the first embodiment of the present invention.

2 is a cross-sectional view of the fan motor in the second embodiment of the present invention.

3 is an A-A perspective view of FIG.

4 is a B-B perspective view of FIG.

5 is a partial detailed view of FIG.

6 is a diagram showing another configuration example of the foil bearing.

7 is a cross-sectional view of a conventional fan motor.

* Explanation of symbols for the main parts of the drawings

1,21: Fan motor 2,22: Casing

3,4: Bearing part 5,26: Fan

6,27: diffuser 7,28: brushless motor

8,31: rotor shaft 9,29: rotor

10,30: Stator 11,20: Intake vent

12: Fixing bolt 13,14a, 14b, 33a, 33b: Spiral groove

15,39: position detecting plate 23: bearing member

24: elastic support piece 25: bearing cylinder

33: bearing (dynamic air bearing) 34: air hole

35: elastic bearing (foil bearing) 36: foil

37: fixed key 38: doble rail groove

The present invention relates to a fan motor suitable for high speed rotation.

In the conventional electric sweeper, the fan motor which supported the both ends of the rotor shaft which fixed the fan to the one end by the ball bearing was used.

Referring to FIG. 7, a specific configuration example of the conventional fan motor 40 will be described. (41) is a stator, 42 is a rotation, 43 is a brush, and 44 is a commutator. The fan 46 is fixed to one end of the rotor shaft 45 by the 42 and the commutator 44. The rotor shaft 45 is rotatably supported between the fan 46 and the rotor 42 by the first bowl bearing 47 and the other end by the second bowl bearing 48. 49 denotes an intake port of the fan 46, and 50 denotes a diffuser. Next, the operation will be described. The rotor 42 is rotated at high speed by energizing the rotor 42 through the commutator 44 from the brush 43, and fixed to one end thereof via the rotor shaft 45. The fan 46 is rotated to suck in air from the inlet port 49, and the air is exhausted through the diffuser 50.

By the way, in the electric cleaning machine of the present development, although the normal fan 46 is rotating at 20,000-30,000 rpm, when trying to raise the rotational speed to 50,000-60,000 rpm for the purpose of miniaturization, the brush 43 and The noise and vibration generated by the bearings 47 and 48 supporting the contact portion of the commutator 44 and the rotor shaft 45 are increased, and their lifetime is shortened and the torque loss is also increased, resulting in poor efficiency. There was.

On the other hand, the problem caused by the contact of the brush 43 and the commutator 44 can be solved by the adoption of the brushless motor, but the noise, vibration caused by the ball bearing, shortening the bearing life, torque The worsening of the losses remained a problem.

Therefore, the main object of the present invention is to provide a fan motor that can achieve low noise, long life and high efficiency even at high speed, and can be miniaturized.

In addition, another object of the present invention is to provide a fan motor capable of high speed rotation even with low axial center precision.

In order to achieve this object, the fan motor of the present invention rotates the rotor shaft on which the fan is fixed by a thrust air bearing which generates a thrust force against the thrust force generated by the rotation of the fan, and a radial bearing. It consists of a material support. Moreover, the fan motor of this invention elastically supports the edge part of the rotor shaft to which the fan was fixed.

With the above configuration, the present invention can achieve low noise and high efficiency even at high speed rotation. In addition, by elastically supporting the end of the rotor shaft, the height of the shaft can be rotated even if the shaft center precision is low.

Example 1

Hereinafter, a first embodiment of the present invention will be described with reference to FIG.

(1) is a fan motor provided in the main body of the electric cleaner (not shown), and a dust collecting filter (not shown) is disposed in front of the inlet 11 of the front end, and a suction port (not shown) is provided through a suction hose (not shown). ) Is communicating.

(2) is a casing, which is divided into a front casing 2a and a rear casing 2b. At the front end shaft center position of the front casing 2a, a first cylindrical cylindrical bearing portion 3 is formed, the front end of which is closed, and an inlet 11 is formed around the rear casing, and the rear end of the rear casing 2b. The cylindrical second bearing portion 4 is formed at the minor axis position.

The fan 5 and the diffuser 6 are disposed in the front casing 2a, and the brushless motor 7 is disposed in the rear casing 2b.

(8) is a rotor shaft whose one end is rotatably supported by the second bearing part 4 in the first bearing part 3. The fan 5 is fixed to the front part of this rotor shaft 8, and the rotor 9 of the brushless motor 7 is fixed to the rear part. The stator 10 is wound around the outer periphery of the rotor 9 at an appropriate interval, and is fixed to the rear casing 2b by the fixing bolt 12. The diffuser 6 is located on the back of the fan 5 and is attached to the front casing 2a. A narrow passage is formed between the outer circumference of the diffuser 6 and the inner circumferential surface of the front casing 2a, and a plurality of guide pins 6a are formed. 6b is a rib formed in the diffuser 6.

A plurality of spiral grooves 13 are formed on the outer periphery of the one end of the rotor shaft 8 inserted into the first bearing portion 3. The spiral groove 13 is formed by lubricating air between the first bearing portion 3 and the rotor shaft 8 by rotating the rotor shaft 8 to the inner bottom surface 3a of the first bearing portion 3. It is formed so as to be squeezed toward, and constitutes an air bearing which generates a drust force against the thrust force generated by the fan 5. In addition, in order to bias the rotor shaft 8 so that the end surface 8a of the rotor shaft 8 is in point contact with the axial center position of the inner bottom surface 3a of the first bearing part 3, the rotor ( 9) and the stator 10 are slightly eccentric in the axial direction. On the outer periphery of the other end of the rotor shaft 8, which is inserted into the second bearing portion 4, a pair of spiral grooves 14a and 14b each formed of a plurality of rows of grooves are formed. These spiral grooves 14a and 14b are formed in a so-called herringbone shape, and the spiral air is lubricated between the second bearing portion 4 and the rotor shaft 8 by the rotation of the rotor shaft 8. It is formed so as to be fed to an intermediate portion between the grooves 14a and 14b to constitute a radial air bearing.

Denoted at 15 is a position detection plate for detecting the rotational position of the brushless motor 7 and conducting electricity control.

Next, the operation will be described.

When the stator 10 of the motor 7 is energized, the rotor 9, the rotor shaft 8, and the fan 5 start to rotate, and the rotor 9 and the stator 10 The rotor shaft 8 is urged forward by the eccentricity in the axial direction, and its one end face 8a abuts against the inner bottom face 3a of the first bearing portion 3 and is positioned. After that, when the rotation speed increases, the lubricating air is pushed toward the inner bottom of the first bearing part 3 by the pumping action of the spiral groove 13 in the first bearing part 3, and the pressure thereof increases. The pressure acting on the inner circumferential surface of the first bearing portion 3 and the one end surface 8a of the rotor shaft 8 acts backward toward the rotor shaft 8. By this thrust force, the thrust force is supported to the front which acts on the rotor shaft 8 according to the rotation speed of the fan 5.

In the second bearing portion 4, the lubricating air is pressurized between the spiral grooves 14a and 14b by the pumping action of the spiral grooves 14a and 14b, and the pressure thereof rises. The bearing action in the radial direction is generated by the wedge action of the lubricating air between the inner circumferential surface of the second bearing portion 4 and the outer circumferential surface of the rotor shaft 8. Thus, since both ends of the rotor shaft 8 are rotatably supported by air bearings in a non-contact manner, even if the motor is rotated at a high speed at a rotational speed of 50,000 to 60,000 rpm, it does not generate noise or vibration and has a long life and torque. There is less loss.

In addition, the air sucked from the inlet port 11 by the rotation of the fan 5 receives the centrifugal force by the fan 5 and is pumped toward the outer periphery thereof, and guides 6a through the narrow passage of the outer periphery of the diffuser 6. After passing through the guide, it diffuses in the rear portion and is discharged from the rear surface of the rear casing 2b through the outer circumference of the stator 10.

In the present embodiment, the air bearing has a spiral groove in the bearing portion, but for example, a pressure generating means is formed separately on the rotor shaft to provide a static pressure air bearing for introducing the pressure. Air bearings can also be used.

As described above, according to the present embodiment, since the rotor shaft is supported by the air bearing, the bearing life can be extended even without high noise or vibration in the bearing portion even when rotating at high speed, and as a lubricating fluid. Since less viscous air is used, less torque loss is achieved at high speeds, and high efficiency can be achieved. In addition, the thrust load generated by the rotation of the fan can be supported by the thrust air bearing.

In addition, one pair or a plurality of first air bearings having one end of the rotor shaft and a first cylindrical bearing member having a spiral groove, and having a spiral groove, the other end of the rotor shaft, and a second bearing portion having a cylindrical shape. By using two air bearings of the second air bearing having a pair of spiral grooves, it is possible to support the thrust force while supporting the rotor in a simple configuration without receiving air from the outside or the like.

In addition, by attaching such a high-speed rotation fan motor to the electric sweeper, it is possible to reduce the size, low noise and high efficiency.

Example 2

Next, the fan motor in the second embodiment of the present invention will be described with reference to FIGS.

In the present embodiment, the main point different from the first embodiment is that the end of the rotor shaft is elastically supported.

In Fig. 2, reference numeral 21 denotes a fan motor provided in the main body of the electric sweeper (not shown), and a dust collecting filter (not shown) of the main body of the electric sweeper is provided in front of the inlet 20 of the front end. (Not shown) to communicate with the suction port.

Reference numeral 22 is a casing, which is divided into a front casing 22a and a rear casing 22b. At the front end shaft center position of the front casing 22a, a user cylindrical bearing member 23 with its front end closed is disposed, and the shaft support is formed by the elastic support piece 24 extending radially from the bearing member 23. It is elastically supported to be able to shake around the point of. The inlet port 20 is formed by the space between these elastic support pieces 24. At the rear end shaft center position of the rear casing 22b, a cylindrical bearing cylinder 25 is disposed.

The fan 26 and the diffuser 27 are arrange | positioned in the front casing 22a, and the brushless motor 28 is arrange | positioned in the rear casing 22b.

The brushless motor 28 is composed of the rotor 29 and the stator 30 wound around the outer circumference at a suitable interval, and the rotor 29 is integrally formed at the rear of the rotor shaft 31. The stator 30 is fixed to the rear casing 22b by the fixing bolt 32.

The fan 26 is fixed to the front part of the rotating shaft 31, and the diffuser 27 is located in the back part of the fan 26, and is attached to the front casing 22a. A narrow passage is formed between the outer circumference of the eiffuser 27 and the inner circumferential surface of the front casing 22a, and a plurality of guide pins 27a are installed. Reference numeral 27b is a rib formed in the diffuser 27.

The front end of the rotor shaft 31 is fitted in the bearing member 23 at an appropriate interval, and a pair of spiral grooves 33a and 33b each having a plurality of grooves are formed on the outer circumference thereof. It is formed in what is called a herringbone shape. The bearing member 23 is provided with an air hole 34 for supplying external air to the boundary between the spiral grooves 33a and 33b, and a filter 34a for removing dust from the opening to the outside. It is installed. The front spiral groove 33a is formed so as to feed the lubricating air between the bearing member 23 and the rotor shaft 31 toward the inner bottom surface 23a of the bearing member 23 by the rotation of the rotor shaft 31. Then, the dynamic pressure air bearing 33 which produces the thrust force against the thrust force produced by the fan 26 is comprised. The rear spiral groove 33b prevents dust from infiltrating between the bearing surfaces by sending air toward the opening end of the bearing member 23. The one end surface 31a of the rotor shaft 31 is formed in the spherical surface so as to be in point contact with the axial center position of the inner bottom surface 23a of the bearing member 23, and immediately after the energization to the brushless motor 28. In the initial stage of rotation, the rotor and the stator are slightly eccentric in the axial direction in order to bias the rotor shaft 31 so as to make point contact between them.

The other end of the rotor shaft 31 is fitted into the elastic bearing 35 formed on the inner circumference of the bearing cylinder 25. The elastic bearing 35 may be any type as long as it is capable of supporting abundant elasticity. In the embodiment of FIG. 2, an example is provided with a foil bearing (see machin design, 1979, June). Doing. As shown in Fig. 4, the elastic bearing 35 has a bearing surface 35a formed of a thin foil 36 having a small deformation resistance such as a metal foil or a plastic film, and the bearing surface 35a. Between the outer circumference of the paddle) and the inner circumferential surface of the bearing control 25, a shock absorbing portion 35b in which the foil 36 is formed into a wave shape is formed. Reference numeral 37 is a fixing key for fixing the foil 36, and is embedded in the dovetail groove 38 formed in the inner circumference of the bearing cylinder 25 as shown in FIG. Reference numeral 39 denotes a position detection plate for detecting the rotational position of the brushless motor 28 and conducting electricity control.

Next, the operation will be described.

When the stator 30 of the brushless motor 28 is energized, the rotor 29 and the rotor shaft 31 revolve the rotation, and at the same time, the eccentricity of the rotor 29 and the stator 30 in the axial center direction. As a result, the rotor shaft 31 is urged forward, and its one end face 31a abuts against the inner bottom face 23a of the bearing member 23 for positioning.

Then, when the rotational speed increases, the lubricating air is pushed toward the inner bottom of the bearing member 23 by the pumping action of the spiral groove 33a in the dynamic pressure bearing 33, and the pressure thereof rises, and the bearing member 23 The radial load is supported by the wedge effect of the lubricating air between the inner circumferential surface of the crankshaft and the outer circumferential surface of the rotor shaft 31. At the same time, the pressure acting on the one end surface 31a of the rotor shaft 31 generates a thrust force to the rear of the rotor shaft 31, and the thrust force causes the fan 26 to rotate. Therefore, the forward facing thrust acting on the rotor shaft 31 is supported.

In addition, since the rear end of the rotor shaft 31 is separated from the fan 26, no large radial load is applied, and the rear end of the rotor shaft 31 is supported by the foil bearing 35. The foil bearing 35 stably supports the rotor shaft 31 that rotates at high speed, and absorbs the shaft center error with the dynamic pressure bearing 33 by the foil bearing 35.

In addition, since the bearing member 23 is elastically supported by the elastic support piece 24 so as to shake the neck, the bearing member 23 easily follows the inclination of the rotor shaft 31. Therefore, the rotor shaft 31 is stably supported even if the shaft center precision is poor.

Thus, since both ends of the rotor shaft 31 are supported by the dynamic pressure bearing 33 and the foil bearing 35 in a non-contacting and careful manner, noise or vibration can be generated even at a high speed rotation at a rotational speed of 50,000 to 60,000 rpm. It does not occur, and it has a long life and a small torque loss.

The air sucked in from the inlet port 20 by the rotation of the fan 26 receives centrifugal force by the fan 26 and is pumped toward the outer periphery thereof, and the narrow passage of the outer periphery of the diffuser 27 guides the guide fan 27a. Therefore, after passing through, it diffuses from the rear part, passes through the outer circumferential space of the stator 30, and is discharged from the rear face of the rear casing 22b.

In addition, in the foil bearing 35 of this embodiment, the bearing surface 35a and the buffer part 35b which were continuous over the whole circumference were formed by the single foil 36, but was shown in FIG. As described above, the bearing surface 35a and the shock absorbing portion 35b may be divided into a plurality in the circumferential direction, and each may be formed by the foil dividing piece 36a.

Alternatively, other types of elastic bearings such as elastomer bearings may be substituted.

As described above, according to the present embodiment, in addition to the effect obtained in the first embodiment, the eccentricity can be absorbed by the elastic bearing even if the axial accuracy between the bearing portions is poor, so that the assembly and the processing precision do not have to be strictly. Therefore, it is possible to easily mass-produce a rotating device capable of high speed rotation.

Moreover, the inclination of a rotating shaft can also be absorbed by taking the support method which can be shaken with respect to an air bearing.

In addition, the air bearing is composed of a user cylindrical flat bearing member and a spiral groove for pumping air toward the inner bottom thereof, so that the thrust load can be supported, and the high-speed rotation generating the thrust force of the fan motor, etc. It can be applied to devices, and it has a great effect.

According to the fan motor of the present invention, since the rotor shaft is rotatably supported by the air bearing, the bearing life can be lengthened even without high noise or vibration in the bearing portion even at high speed rotation, and the viscosity as a lubricating fluid can be achieved. Since this small air is used, torque loss at high speed rotation is small and high efficiency can be achieved.

Moreover, according to the fan motor of this invention, even if the axial center precision between bearing parts is bad, it has an effect which can absorb the eccentricity by an elastic bearing.

Claims (6)

A fan motor, wherein the rotor shaft on which the fan is fixed is rotatably supported by a thrust air bearing that generates a thrust force against the thrust force generated by the rotation of the fan, and a radial air bearing. . 2. The spiral according to claim 1, wherein one end of the rotor side on which the fan is fixed is fitted to the first bearing part of the user cylinder shape, and the spiral pumps air toward the inner bottom by rotation of the rotor shaft on one of the opposing cylindrical surfaces. A pair or plural pairs of grooves which form grooves and fit the other ends of the rotor shafts to the second bearings of the cylindrical yarn and simultaneously pressurize air toward their intermediate portions by rotation of the rotor shafts on one of the cylindrical surfaces facing each other. Fan motor characterized by forming a spiral groove. A fan motor, wherein one end of the rotor shaft on which the fan is fixed is supported by an air bearing, and the other end is supported by an elastic bearing. 4. The fan motor according to claim 3, wherein the air bearing is provided with abundant elasticity so that the air bearing can be shaken with approximately one point on its axis. 4. The bearing member according to claim 3, wherein the air bearing is formed on one of a user cylindrical bearing member to which one end of the rotor shaft fits, and a cylindrical surface of the rotor shaft and the bearing member facing each other so that air is rotated by the rotation of the rotor shaft. Fan motor characterized in that it has a spiral groove that is pumped toward the inner bottom of the. One end of the rotor shaft on which the fan is fixed is supported by the air bearing, and the other end is supported by the elastic bearing, and the air bearing is capable of shaking the neck at approximately one point on the center of the shaft and is elastically rich in support. Fan motor characterized in that there is.

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