JP2002070791A - Axial flow fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the impact of an external force on bearing members and to improve reliability of the life of the bearing members, in particular, ball bearings. SOLUTION: The axial flow fan according to the present invention is configured such that a bearing member to be arranged on a rotor hub is movably held in the axial direction on the inside peripheral surface of a bearing housing in a non-fixed fit state so that the bearing member always abuts against the rotor hub by means of spring members interposed between the bearing member and a barrel-bearing stepped portion of the inside peripheral surface of the bearing housing, and at the same time, a distance between the bottom inside surface of the rotor hub and the tip of a small diameter cylindrical part forming the bearing housing opposed to the bottom inside surface, or a distance between the tip of the cylindrical part of the rotor hub and the tip of the motor supporting part opposed to the tip of the cylindrical part of the rotor hub, is smaller than the movable distance of the bearing member in the bearing housing, and further the distance between the tip of the bearing housing and the bottom inside surface of the rotor hub is smaller than the distance between the bottom inside surface of the rotor hub and other opposed parts of the stator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial fan, and more particularly to an axial fan which uses a ball bearing as a bearing member and which needs to avoid external impact on the bearing member.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of an example of an axial fan driven by a DC brushless motor according to the prior art.

[0003] A venturi case 1 having a cylindrical wind tunnel portion 1-1 is provided with a motor holding portion 1-3 concentrically provided by a plurality of legs 1-4 provided at one end thereof so as to cross the ventilation passage. I have. The motor holding portion 1-3 includes a small-diameter cylindrical portion 1-2 forming a bearing housing, and mainly includes a stator core 6-1 having a stator winding 6-2 wound on an outer peripheral surface thereof. The rotor shaft 8 is supported by a bearing member 9 which is fitted and held in a bearing box 1-2 formed by an inner peripheral surface,
An electric motor 6 is configured by rotating a permanent magnet 5 using a back yoke 4, which mainly forms a rotor, via a rotor hub 3 fastened and held to the rotor shaft 8. The impeller 2 is integrally formed and includes a plurality of blades 2-1 arranged in the wind tunnel 1-1.

[0004]

The conventional structure as described above is characterized in that the small-diameter cylindrical portion 1 which is a portion where the fixed portion and the rotating portion are in contact with each other.
-2 and the inner surface of the bottom of the rotor hub 3 opposed thereto, and between the distal end of the motor holding portion 1-3 and the distal end of the cylindrical portion 3-1 of the rotor hub 3 opposed thereto. It is configured so as to be separated and not to hinder the rotation operation.

On the other hand, since the bearing member 9 for supporting the rotating portion is disposed in direct contact with the step portion of the bearing box 1-2 as shown in the drawing, the bearing member 9 is positioned rightward in the drawing. One of the bearing members 9 is restricted from moving leftward.
For example, when an impact is applied to the back surface of the rotor hub 3, the impact force is directly transmitted to the bearing member 9. For example, when the bearing member 9 is a ball bearing, ball rolling of the inner and outer rings is caused by the interposed balls. There is a risk of surface damage.

[0006]

SUMMARY OF THE INVENTION An axial fan according to the present invention has a small diameter formed integrally with a cylindrical wind tunnel portion by a plurality of feet so as to be concentric with the wind tunnel portion to form a bearing housing. A Venturi case comprising a motor holding portion having a cylindrical portion; a stator held by a small-diameter cylindrical portion forming the bearing box, having a stator core wound with a stator winding, and fitted to the bearing box. A motor having a rotor rotatably supported by a matingly mounted bearing member and provided so as to face the outer peripheral surface of the stator with a small gap therebetween, and a rotor integrated with the rotor It has a hub and a plurality of blades implanted and arranged on the outer peripheral surface thereof, and is provided with an impeller opposed to the inner surface of the wind tunnel portion via a small gap.

The bearing member provided on the rotor hub side is mounted on the inner peripheral surface of the bearing box in a non-fixed fitting state and held so as to be movable in the axial direction, and the bearing member and the inner peripheral surface of the bearing box are provided. A spring member interposed between the body and the stepped portion of the surface is held so as to be constantly pressed against the rotor hub, and is opposed to the bottom inner surface of the rotor hub and the bottom inner surface. The distance between the tip of the small-diameter cylindrical portion forming the bearing box, or the distance between the tip of the rotor hub cylindrical portion and the tip of the electric motor holding portion facing the rotor hub can move the bearing member in the bearing box. The distance between the front end of the bearing housing and the inner surface of the bottom of the rotor hub is smaller than the distance, and the distance between the inner surface of the bottom of the rotor hub and other portions of the stator facing each other. It is configured to be smaller.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an axial fan 1 in which a DC brushless motor is used as a driving motor 6 as in the above-mentioned prior art. A motor holding section 1-3 has a control circuit 7 for driving the motor 6. The interior is also arranged.

Also in this example, the motor holding unit 1 is concentrically provided on a venturi case 1 having a cylindrical wind tunnel 1-1 by a plurality of legs 1-4 provided at one end thereof so as to cross the ventilation path.
The motor holding portion 1-3 includes a small-diameter cylindrical portion 1-2 forming a bearing housing, and a stator core 6-2 having a stator winding 6-2 wound on an outer peripheral surface thereof. 1 is held, and the rotor shaft 8 is supported by a bearing member 9 which is fitted and held in a bearing box 1-2 formed by an inner peripheral surface, and is fastened and held by the rotor shaft 8. The motor 6 is formed by rotating a permanent magnet 5 using a back yoke 4 mainly comprising a rotor via a rotor hub 3 formed integrally with the rotor hub 3 and the wind tunnel 1-1. The overall configuration for driving the impeller 2 including the plurality of blades 2-1 arranged in
Although there is no difference from the above-mentioned prior art, the mounting configuration of the bearing member 9 fitted in the bearing box 1-2 is different.

As shown in the figure, of the two bearing members 9 fitted on the inner peripheral surface of the bearing box 1-2, the bearing member 9 on the side which comes into contact with the rotor hub 3 shown on the right side of the figure. Is the bearing box 1-
2 is fitted to the inner peripheral surface of the fitting 2 in a non-fixed state so that the inner peripheral surface can move in the axial direction, and a spring member 10 is provided between the inner peripheral surface and the step formed on the inner peripheral surface. It is inserted and mounted.

That is, the bearing member 9 is always pressed against the boss end of the rotor hub 3 by the spring member 10 used in combination.

The axially movable distance of the bearing member 9 is a separation distance δ between the inner surface of the bottom of the rotor hub and the tip of the small-diameter cylindrical portion forming the bearing box facing the inner surface of the bottom. Alternatively, it is configured to be larger than the separation distance δ ′ between the tip of the rotor hub cylindrical portion and the tip of the electric motor holding portion opposed thereto.

According to the above configuration, for example, the rotor hub 3
Even if some external force acts on the back surface of the bearing member 9 to apply a force that pushes the rotating part of the axial fan 1, the bearing member 9
Is larger than the above-mentioned δ or δ ′, the transmission of the impact is carried out at the tip of the small-diameter cylindrical portion which forms the bottom inner surface of the rotor hub and the bearing box opposed to the bottom inner surface, or the rotor hub. Since the distal end of the cylindrical portion and the distal end of the electric motor holding portion opposed thereto come into contact with each other in advance, the bearing member 9 which is vulnerable to impact is avoided.

A bottom inner surface of the rotor hub 3 and a distal end of a small-diameter cylindrical portion 1-2 forming the bearing box facing the bottom inner surface;
Alternatively, the contact between the tip of the cylindrical portion of the rotor hub 3 and the tip of the electric motor holding portion 1-3 facing the contact is, of course, the contact between the rotating portion and the fixed portion, and therefore should not be normal. In addition, as described above, in preparation for an impact by an external force, it is essential to abut each other before any other, so the separation distance between the other rotating part and the fixed part, Needless to say, it is larger than the above δ, δ '.

Further, the drive motor 6 is not limited to the DC brushless motor described above, but can be applied to various practical motors.

[0017]

According to the axial flow fan of the present invention, since the impact on the bearing member due to the external force can be avoided, the reliability of the life of the bearing member, especially the ball bearing, can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of an axial fan according to the present invention.

FIG. 2 is a sectional view of an example of an axial fan according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Venturi case 11-1 Cylindrical wind tunnel part 1-2 Small diameter cylindrical part which forms a bearing box 1-3 Motor holding part 1-4 Leg 2 Impeller 22-1 Blade 3 Rotor hub 3-1 Cylindrical part 4 Back yoke Reference Signs List 5 permanent magnet 6 electric motor 6-1 stator core 6-2 stator winding 7 control circuit 8 rotor shaft 9 bearing member 10 spring member

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H022 AA03 BA02 BA04 BA06 CA12 CA19 DA13 3H033 AA02 BB02 BB08 BB20 CC01 CC03 CC04 CC06 DD12 EE11 3H034 AA02 BB02 BB08 BB19 BB20 CC01 CC03 CC04 CC06 DD14 EE11

Claims (4)

[Claims] 1. A venturi having a cylindrical wind tunnel portion and a motor holding portion having a small-diameter cylindrical portion integrally connected by a plurality of feet so as to be concentric with the wind tunnel portion to form a bearing housing. A stator having a stator core with a stator winding wound thereon, the stator fixed to the outer peripheral surface of a small-diameter cylindrical portion forming the bearing box, and a bearing member fitted to the bearing box A rotor which is rotatably supported by the rotor and is provided so as to face the outer peripheral surface of the stator with a small gap therebetween, a rotor hub integral with the rotor, and an outer peripheral surface thereof An impeller having a plurality of blades implanted and disposed on the inner surface of the wind tunnel portion with a small air gap therebetween, wherein the bearing member disposed on the rotor hub side comprises: Attached to the inner peripheral surface of the bearing housing in a non-fixed fitting state and movable in the axial direction The distance between the bottom inner surface of the rotor hub and the tip of the small-diameter cylindrical portion forming the bearing box facing the bottom inner surface is smaller than the movable distance of the bearing member in the bearing box. An axial fan. 2. A venturi having a cylindrical wind tunnel portion, and a motor holding portion having a small-diameter cylindrical portion integrally connected to the wind tunnel portion with a plurality of legs to form a bearing housing. A case, a stator having a stator core on which a stator winding is wound, a stator fixed to the outer peripheral surface of a small-diameter cylindrical portion forming the bearing box, and a bearing member fitted to the bearing box. A motor having a rotor rotatably supported and provided so as to face the outer peripheral surface of the stator via a small air gap, a rotor hub integral with the rotor, and an outer peripheral surface thereof. An impeller having a plurality of implanted blades, the impeller being opposed to the inner surface of the wind tunnel portion via a small air gap, wherein the bearing member provided on the rotor hub side comprises the bearing Attached to the inner peripheral surface of the box in a non-fixed fitting state and movable in the axial direction Held, the rotor hub cylindrical portion tip, and the distance between the tip of the electric motor holding portion opposed thereto is configured to be smaller than the movable distance of the bearing member in the bearing box, A feature of the axial fan. 3. The bearing member which is movable in the axial direction on the inner peripheral surface of the bearing housing is always connected to the rotor hub by a spring member interposed between the inner peripheral surface of the bearing housing and a stepped portion of the body. 2. The structure according to claim 1, wherein the contact member is configured to be pressed against and contacted.
Or the axial flow fan according to any one of 2. 4. A distance between the front end of the bearing housing and the inner surface of the bottom of the rotor hub is smaller than the distance between the inner surface of the bottom of the rotor hub and other portions of the stator facing each other. The axial flow fan according to any one of claims 1 to 3, wherein the axial flow fan is configured as follows.