JPH09324795A - Installing structure of fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installing structure of a fan by which a noise is reduced by preventing vibration transmitted to the fan by. being transmitted in a rotary shaft in the installing structure of a fan. SOLUTION: In an installing structure of a fan which is composed of a rotary shaft 2 of an electric motor 1 where a D cut part 2b is formed in a tip part and a screw part 2a is formed on the tip of the D cut part, an almost cylindrical boss part 3a where an inserting hole 3a1 to insert the rotary shaft is formed in the center and a flat part 3a2 corresponding to the D cut part is formed in the inserting hole, a cylinder part 3d and a fan 3 having a reinforcing rib 3c between the cylinder part and the periphery of the boss part 3a, and is formed by fastening the fan 3 to one end of the rotary shaft by a nut 5 through a washer 4, a rib 3a3 projecting in the shaft direction is formed on an inner wall between the flat part and the opening end of the inserting hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for mounting a fan, and more particularly to a structure for fixing a fan and a rotating shaft and a soundproof and vibration-proof structure.

[0002]

As an example of a conventional technique, as shown in FIG. 5, a rotary shaft 2 of an electric motor 1 having a D-cut portion 2b formed at its tip and a screw portion 2a formed at the tip of the D-cut portion, A substantially cylindrical boss portion 3a having a through hole 3a1 through which the rotary shaft is inserted and a flat portion 3a2 corresponding to the D cut portion formed in the through hole, a cylindrical portion 3d, and a cylindrical portion of the cylindrical portion. The fan 3 is provided with a reinforcing rib 3c between the periphery and the boss portion, and the fan is fastened to one end of the rotary shaft by a nut 5 via a washer 4.

In this case, the clearance between the rotary shaft and the insertion hole of the boss portion is generated due to the taper on the molding of the fan, and this clearance is on the motor body side of the insertion hole of the boss portion. Maximum at the opening of. Therefore, there is a possibility that the vibration generated by the rotation of the electric motor of the fan is transmitted through the rotary shaft and may be amplified by the vibration and resonance of the fan to generate noise that is twice or four times the power supply frequency. Has occurred.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a fan mounting structure in which vibration transmitted through a rotating shaft and transmitted to a fan is prevented to reduce noise. The purpose is to:

[0005]

In order to achieve the above object, a D-cut portion is formed at a tip portion and a screw portion is formed at a tip of the D-cut portion, and an insertion member for inserting the rotation shaft. And a fan having a substantially cylindrical boss portion having a hole formed at the center and a flat portion corresponding to the D-cut portion formed in the insertion hole. The fan is fastened to one end of the rotary shaft with a nut. In the fan mounting structure as described above, a rib protruding in the axial direction is formed on the inner wall between the flat portion and the opening end of the insertion hole.

Then, the ribs are provided on both sides of a position close to the flat portion.

Further, the rib is formed to have a length from at least the end surface of the flat portion to a position where the head of the screw portion projects from the boss portion and the nut is engaged when the rotary shaft is inserted through the insertion hole. I will do it. further,
The height of the rib is gradually increased from the opening end of the insertion hole toward the flat portion.

On the other hand, the rib is made to have such a height that the insertion hole having an outer diameter smaller than the outer diameter of the rotating shaft excluding the D-cut portion is formed.

Further, the width of the rib is set to be approximately 1/3 of the width of the flat portion.

On the other hand, an auxiliary rib is formed on the inner wall of the insertion hole opposite to the flat portion with respect to the central axis.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A D-cut portion is formed at the tip and a screw shaft is formed at the tip of the D-cut portion, and an insertion hole for inserting the rotation shaft is formed as a center. A fan having a substantially cylindrical boss portion having a flat portion corresponding to the D-cut portion, wherein the fan is attached to one end of the rotary shaft with a nut. A rib protruding in the axial direction is formed on the inner wall between the portion and the opening end of the insertion hole, and the rib reduces the clearance between the rotation shaft and the insertion hole of the boss portion. The fan mounting structure prevents vibration transmitted through the rotating shaft to the fan and reduces noise.

[0012]

Embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same reference numerals are used for the same parts as in the conventional example. 1 is an embodiment according to the present invention, and is a cross-sectional view of a main part of a mounting structure for an electric motor and a fan, FIG. 2 is an enlarged cross-sectional view of the main part of FIG. 1, and FIG. 'It is an enlarged cross-sectional view of a main part.

On the rotary shaft 2 of the electric motor 1, a D-cut portion 2b is formed at the tip and a screw portion 2a is formed at the tip of the D-cut portion. Further, the fan 3 has a substantially cylindrical boss portion 3a which is formed around an insertion hole 3a1 through which the rotary shaft is inserted, and a flat portion 3a2 corresponding to the D cut portion is formed in the insertion hole, and a cylindrical portion. 3d, and a reinforcing rib 3c is provided between the cylindrical portion and the periphery of the boss portion.

Here, the material of the fan is glass-filled AS
(Acrylonitrile styrene) or PP (polypropylene), ribs 3a3 protruding in the axial direction are formed on the inner wall between the flat portion and the opening end of the insertion hole. Then, the fan is attached to one end of the rotary shaft with a washer 4
It is fastened by the nut 5 via the.

Further, the rib has a length d from at least the end face of the flat portion to a position where the head of the screw portion projects from the boss portion and the nut is hooked when the rotary shaft is inserted into the insertion hole. On the other hand, while forming the rib, the rib is made to have a height h such that the insertion hole having an outer diameter smaller than the outer diameter of the rotating shaft excluding the D-cut portion is formed. , The width wf of the flat portion is approximately 1
/ 3.

Alternatively, as shown in FIG. 3, the height of the rib may be gradually increased from the opening end of the insertion hole toward the flat portion. Alternatively, as shown in FIG. 4B, the ribs may be provided on both sides of a position close to the flat portion. On the other hand, as shown in FIG. 4C, an auxiliary rib may be formed on the inner wall of the insertion hole on the side opposite to the flat portion with respect to the central axis.

The vibration damping effect of the rib will now be described. Since the boss portion is tightly fitted to the rotating shaft, the clearance between the boss portion is small, but the clearance is small, but the clearance is eccentric. However, the rib reduces the clearance between the rotary shaft and the insertion hole of the boss portion, and gradually increases the height of the rib from the opening end of the insertion hole toward the flat portion. By forming the main rib and forming the auxiliary rib, the minute clearance is dispersed and eccentricity is reduced. As a result, the transmission of the rotational vibration of the electric motor to the fan is greatly reduced, and the frequency of the power is doubled.
Quadruple resonance is also prevented.

Further, the workability of assembling the rotary shaft and the boss portion is good. In this embodiment, the mounting structure of the electric motor and the fan is used, but the present invention is not limited to the electric motor.

[0019]

As described above, according to the present invention, the D-cut portion is formed at the tip and the screw shaft is formed at the tip of the D-cut portion, and the insertion hole through which the rotation shaft is inserted is centered. And a fan having a substantially cylindrical boss portion having a flat portion corresponding to the D-cut portion formed in the insertion hole, the fan being formed by fastening the fan to one end of the rotary shaft with a nut. In the mounting structure of (1), a rib protruding in the axial direction is formed on the inner wall between the flat portion and the opening end of the insertion hole. Reduce the clearance between the insertion holes.

As a result, it is possible to provide a fan mounting structure in which the vibration transmitted through the rotating shaft to the fan is prevented and the noise is reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a fan mounting structure according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG.

FIG. 3 is an enlarged sectional view of an essential part showing another embodiment of a fan mounting structure according to the present invention.

4A is an enlarged cross-sectional view of an essential part showing a cross section taken along line AA ′ in FIG. 2, and FIGS. 4B and 4C are enlarged cross-sectional views of an essential part showing another embodiment.

FIG. 5 is a cross-sectional view of essential parts showing an example of a conventional fan mounting structure.

[Explanation of symbols]

 1 Electric Motor 2 Rotating Shaft 2a Screw Part 2b D Cut Part 3 Fan 3a Boss Part 3a1 Insertion Hole 3a2 Flat Part 3a3 Rib 3b Auxiliary Rib 3c Reinforcing Rib 3d Tube Part 4 Washer 5 Nut d Rib Length w Rib Width h Rib Height wf Width of flat part

Claims (7)

[Claims] 1. A rotary shaft having a D-cut portion formed at a front end thereof and a screw portion formed at the front end of the D-cut portion, and an insertion hole through which the rotary shaft is inserted are formed around the rotary shaft. A fan mounting structure comprising a substantially cylindrical boss portion having a D-cut portion and a flat portion corresponding to the D-cut portion, wherein the fan is attached to one end of the rotary shaft with a nut. A fan mounting structure, characterized in that a rib protruding in the axial direction is formed on an inner wall between the opening end of the insertion hole. 2. The fan mounting structure according to claim 1, wherein the ribs are provided on both sides of a position close to the flat portion. 3. The rib is formed to have a length from at least an end surface of the flat portion to a position at which a head of the screw portion projects from the boss portion and a nut is engaged when the rotary shaft is inserted into the insertion hole. The method according to claim 1, wherein
The mounting structure of the described fan. 4. The fan mounting structure according to claim 1, wherein the height of the rib is gradually increased from the opening end of the insertion hole toward the flat portion. 5. The rib is formed at a height such that the insertion hole having an outer diameter smaller than the outer diameter of the rotating shaft excluding the D-cut portion is formed. Fan mounting structure. 6. The fan mounting structure according to claim 1, wherein the width of the rib is approximately 1/3 of the width of the flat portion. 7. The fan mounting structure according to claim 1, wherein an auxiliary rib is formed on an inner wall of the insertion hole opposite to the flat portion with respect to the central axis.