JP2017160847A - Motor fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict vibration caused by rotation of a rotor transmitted to a housing while improving axis center accuracy of a bearing with respect to the housing and to reduce vibration of outer shell parts.SOLUTION: In order to solve the problem described above, it is sufficient for a motor fan to have a constitution comprising: a motor part including a stator and a rotor; a fan fixed to a shaft of the rotor; bearings for rotatably supporting the shaft; a bearing housing for holding the bearings; guide blades for feeding air sucked by the fan to the motor; and a blower composed of a fan cover covering the fan and the guide blades, and an outer peripheral portion of each of the bearings is provided with an elastic body and the bearings are held at the bearing housing through the elastic body.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electric blower used for a vacuum cleaner or the like.

  2. Description of the Related Art Conventionally, in an electric blower, an adhesive is injected from a hole provided in at least one peripheral wall of a housing that holds a rolling bearing (hereinafter referred to as a bearing) that supports both ends of a rotor, and a shaft in the housing. A structure that improves the shaft center accuracy of the bearing and reduces vibration and noise by allowing the adhesive to penetrate into the gap between the dent provided along the direction and the bearing outer ring to integrally fix the bearing outer ring and the housing. Is known (see, for example, Patent Document 1).

JP 9-4643 A

  However, in the configuration as described above, since the outer ring of the bearing that supports the rotor that rotates at high speed and the housing are integrally fixed, vibration (excitation force) due to the rotation of the rotor propagates directly to the housing via the bearing. As a result, there is a problem that the vibration of the outer parts increases.

  An object of the present invention is to suppress vibration (excitation force) due to rotation of a rotor transmitted to a housing and reduce vibration of an outer part while improving the axial accuracy of a bearing with respect to the housing.

  In order to solve the above problems, in an electric blower, a motor unit including a stator and a rotor, a fan attached to a shaft of the rotor, a bearing that rotatably supports the shaft, and a bearing are held. A bearing housing, a guide vane for introducing air sucked by the fan into the motor unit, and a blower unit including a fan cover that covers the fan and the guide vane are provided with an elastic body on the outer peripheral portion of the bearing. The bearing may be configured to be held in the bearing housing via an elastic body.

  The present invention improves the axial accuracy of the bearing by the elastic body protruding from the bearing outer ring uniformly filling the gap between the bearing and the housing, and the rotation propagated to the housing by holding the bearing via the elastic body. Vibration due to the rotation of the child can be reduced.

Sectional drawing of the electric blower in Embodiment 1 Sectional view of frame housing in embodiment 1 Enlarged view of the contact portion between the elastic body and the frame housing in the first embodiment Relationship graph between elastic body tightening margin and motor vibration in the first embodiment Sectional drawing of the electric blower in Embodiment 2

Embodiment 1 FIG.
FIG. 1 shows a cross-sectional view of an electric blower 100 according to Embodiment 1 of the present invention.
Here, the electric blower 100 is a commutator motor, but is not limited to a commutator motor, and may be, for example, a brushless DC motor. The electric blower 100 includes a motor unit 101 and a blower unit 102, and rotates at a rated rotational speed of 30000 to 50000 [r / min]. The motor unit 101 includes a stator 6 and a rotor 1.

The rotor 1 is configured by winding a coil in a slot formed by a rotor core 2 in which a plurality of iron plate materials are stacked. A shaft 5 serving as a rotation axis is fixed to the center of the rotor core 2. A commutator 3 is located between the rotor core 2 and a rear bearing 13 described later, and is fixed to the shaft 5. The commutator 3 is electrically connected to the coil of the rotor 1 and comes into contact with the brush 4 fixed to the frame 8 that encloses the stator 6.

  The stator 6 that generates a magnetic force acting on the rotor 1 is formed by stacking a plurality of iron plate materials and winding a coil on a stator core 7 having a pair of magnetic poles via a winding frame made of an insulating material. Composed. The stator 6 is held on the inner periphery of the frame 8, and the rotor 1 is rotatably positioned in a gap between the pair of magnetic poles.

The frame 8 is provided with a frame housing 9 by forming a cylindrical recess. The bracket 10 is provided with a bracket housing 11 by forming a cylindrical recess. The shaft 5 is rotatably supported at one end side by the rear bearing 13 and at the other end side by the front bearing 12. The rear bearing 13 and the front bearing 12 have a cylindrical outer shape.
The rear bearing 13 is inserted into the frame housing 9 and the front bearing 12 is held inside the bracket housing 10. That is, the frame housing 9 and the bracket housing 10 are portions that serve as a bearing housing that holds the rear bearing 13 or the front bearing 12.
The rotor 1 rotates at both ends of the shaft 5 passing through the center thereof by a rear bearing 13 held by a frame housing 9 provided in the frame 8 and a front bearing 12 held by a bracket housing 11 provided in the bracket 10. It is supported freely. The bracket 10 is fixed to the frame 8 with screws.

  The blower unit 102 includes a fan 14 attached to the end of the shaft 5, a guide blade 15 that introduces air sucked by the fan 14 into the motor unit 101, and a fan cover 16 that covers the fan 14 and the guide blade 15. The guide blade 15 is fixed to the bracket 10 with a screw, and the fan cover 16 is fitted and fixed to the outer peripheral end of the frame 8.

FIG. 2 shows an enlarged view of the frame housing 9 part of FIG.
A spring washer 17 and a cushion 18 are inserted between the bottom of the recess forming the frame housing 9 and the rear bearing 13. The spring washer 17 and the cushion 18 press the outer ring 13a of the rear bearing 13, whereby a predetermined preload acting in the axial direction is applied.

This preload means that when the electric blower is driven, the positions of the outer ring 13a, the inner ring 13b, the outer ring 13a, and the rolling element 13c interposed between the outer ring 13b and the inner ring 13b with respect to the outer ring 13a are appropriately maintained. Is for smoothly rotating through the rolling elements 13c.
That is, by applying an upward force (preload) in the drawing to the outer ring 13a in advance, even if the inner ring 13b fixed to the shaft 5 moves upward as the fan 14 rotates, the outer ring 13a and the inner ring 13b And the position of the rolling element 13c is maintained appropriately.

An annular groove 20 is formed in the rear bearing 13 on the side surface of the outer ring 13a which is an outer peripheral portion. An elastic body 19 is fitted inside the groove 20. The elastic body 19 has a portion protruding from the groove 20 and is in contact with the inner peripheral surface 9 a of the frame housing 9. That is, the elastic body 19 protrudes from the outer peripheral side surface of the rear bearing 13 and is in contact with the inner peripheral surface 9 a of the frame housing 9.
Two grooves 20 are formed on the side surface of the outer ring 13a, and an elastic body 19 is provided in each groove. Further, the elastic body 19 has a ring shape, and a cross-section has a circular shape or an elliptical shape, and is provided in the groove 20 so as to make one round of the annular groove 20. The elastic bodies 19 are respectively located on the upper side and the lower side of the rolling elements 13c.
If the cross section of the elastic body 19 is circular or elliptical, the surface of the elastic body 19 is a curved surface. Therefore, the area where the surface of the elastic body 19 and the groove 20 are in contact with each other can be minimized. Thereby, the vibration generated by the rotation of the rotor 1 can be configured to be more difficult to be transmitted to the frame housing 9.
Thus, the rear bearing 13 is held on the inner peripheral surface 9 a of the frame housing 9 via the elastic body 19.

Next, FIG. 3 shows an enlarged view of a contact portion between the elastic body 19 and the frame housing 9. In addition, as for the elastic body 19, what was shown by the continuous line has shown the state which was crushed, and what was shown by the dotted line has shown the state which is not crushed. The elastic body 19 in an uncrushed state is schematically shown for comparison.
In a state where the elastic body 19 is attached to the groove 20 and is not crushed from the outside of the rear bearing 13, that is, in a state where the rear bearing 13 is not provided inside the frame housing 9, the rear bearing 13. It protrudes from the side surface of the outer ring 13a by a protrusion amount ΔD. The outer diameter of the rear bearing 13 including the protrusion amount ΔD is larger than the inner diameter of the frame housing 9.

  Therefore, in a state where the rear bearing 13 to which the elastic body 19 is attached is inserted and attached to the frame housing 9, the elastic body 19 is pushed and crushed and compressed by the inner peripheral surface 9 a of the frame housing 9. At this time, the elastic body 19 is compressed by the compression amount Δd, and the rear bearing 13 and the elastic body 19 are held on the inner periphery of the frame housing 9 with an interference fit.

  Thus, the rear bearing 13 is attached to the frame housing 9 via the elastic body 19. That is, since the elastic body 19 is positioned between the rear bearing 13 and the frame housing 9, a gap is formed between both members, and the rear bearing 13 and the frame housing 9 are difficult to contact.

FIG. 4 shows the relationship between the tightening margin ratio and the motor vibration.
The ratio of the compression amount Δd to the protrusion amount ΔD of the elastic body 19 is defined as a fastening margin ratio (Δd / ΔD × 100 [%]). When Δd is 0, that is, based on the motor vibration when the interference rate is 0%, the motor vibration is approximately 6.2 times when the interference rate is 60%, and the motor vibration when the interference rate is 40%. Is approximately 1.6 times, but the motor vibration when the interference rate is 20% is approximately 0.7 times. When the compression amount Δd of the elastic body 19 is between 0 and 20%, the vibration reduction effect is obtained. can get.
That is, the compression amount Δd may be configured so as not to exceed about 20%. Here, the extent that the amount of compression Δd does not exceed about 20% means that the amount of compression is equal to or less than the motor vibration when the interference rate is 0%. Therefore, even if the value is slightly over 20%, it may be less than or equal to the motor vibration when the tightening margin ratio is 0%. In FIG. 4, the tightening margin ratio at which the vibration is 1.0 or less also falls within the range of values not exceeding about 20%.

Therefore, the rear bearing 13 and the elastic body 19 exhibit a vibration reduction effect by using an interference fit that does not exceed 20%.
Further, the clearance between the rear bearing 13 and the frame housing 9 is uniformly filled with the elastic body 19 by the interference fit, so that the axial center accuracy of the rear bearing 13 with respect to the frame housing 9 is improved.

According to the present embodiment, since the rotor 1 is held on the inner periphery of the frame housing 9 via the elastic body 19, vibration (excitation force) due to the rotation of the rotor 1 is propagated to the frame 8 by the elastic body 19. Since the rotor vibration is reduced by improving the axis accuracy, the vibration of the outer parts can be reduced.
In the present embodiment, the configuration in which the above-described configuration is applied to the rear bearing 13 has been described. However, even if this configuration is used for the front bearing 12, an effect of rotating and reducing vibration can be expected.

Embodiment 2. FIG.
FIG. 5 shows a cross-sectional view of electric blower 103 in Embodiment 2 of the present invention.
Parts having the same functions as those in FIG. The front bearing 12 of the electric blower 103 is held by fixing the outer ring 12 a to the inner periphery of the bracket housing 11 with, for example, an adhesive 23.
As in the first embodiment, the rear bearing 13 is provided with a gap between the outer ring 13 a and the inner periphery of the frame housing 9, filled with the elastic body 19, and held on the inner periphery of the frame housing 9 via the elastic body 19. The

According to the present embodiment, since the front bearing 12 and the bracket housing 11 are integrally fixed, the shaft cores of the rotor 1 and the bracket housing 11 can be positioned coaxially, and the rear bearing 13 has the elastic body 19 attached thereto. Therefore, the axial center accuracy of the rotor 1 and the bracket housing 11 can be maintained regardless of the misalignment between the bracket housing 11 and the frame housing 9.

DESCRIPTION OF SYMBOLS 100: Electric blower 101: Motor part 102: Blower part 1: Rotor 2: Rotor iron core 3: Commutator 4: Brush 5: Shaft 6: Stator 7: Stator iron core 8: Frame 9: Frame housing 9a: Inside Peripheral surface 10: Bracket 11: Bracket housing 12: Front bearing 12a: Outer ring 13: Rear bearing 13a: Outer ring 13b: Inner ring 13c: Rolling element 14: Fan 15: Guide vane 16: Fan cover 17: Spring washer 18: Cushion 19: Elastic body 20: Groove 21: Projection amount 22: Compression amount 23: Adhesive

Claims (5)

A motor unit including a stator and a rotor, a fan attached to a shaft of the rotor, a bearing that rotatably supports the shaft, a bearing housing that holds the bearing, and air sucked by the fan A guide vane for introducing the fan into the motor unit, and a blower unit comprising a fan cover covering the fan and the guide vane,
The outer peripheral portion of the bearing is provided with an elastic body,
The electric blower, wherein the bearing is held by the bearing housing through the elastic body. The elastic body protrudes from the outer peripheral side surface of the bearing,
In a state where the bearing is provided in the bearing housing, the elastic body is pressed against an inner peripheral surface of the bearing housing and is crushed and compressed to be in an interference fit state. Item 4. The electric blower according to Item 1.   The elastic body is used with an interference fit such that the amount of compression in the crushed state does not exceed about 20% with respect to the amount of protrusion from the outer peripheral side surface in the uncrushed state. The electric blower according to claim 2.   The bearing is a rear bearing that supports one end side of the shaft and a front bearing that supports the other end side, and either the front bearing or the rear bearing is fixed to the inner periphery of the bearing housing. The electric blower according to claim 1.   The electric blower according to claim 1, wherein the elastic body has a ring shape.