JPH11262218A - Connecting structure of fan for blower and a motor shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the transmission of electromagnetic vibration to a very low level by electric motor conduction to a fan for blower, to prevent noises die to the vibration of the fan for blower and to permanently maintain the effects. SOLUTION: A plurality of projecting pieces 20 are provided on the inner peripheral face of the through-hole 7 of a fan boss part 5. The projecting pieces 20 are brought into contact with a motor shaft 8 so as to reduce a contact area. Thus, the transmission of electromagnetic vibration by the conduction of an electric motor to the fan boss part 5 becomes extremely small, noise by the vibration of the fan for blower can be prevented, and the effects can be maintained permanently, since elastic bodies are not used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for connecting a fan for a blower used for a range hood, a ventilation fan and the like to a motor shaft of an electric motor.

[0002]

2. Description of the Related Art As a blower used for a range hood, a ventilation fan or the like, a fan using a sirocco fan, a propeller fan, or a turbo fan is known. For example, as shown in FIG. 1, a blower in which a blower fan 2 called a sirocco fan is provided in a blower case 1 and the blower fan 2 is driven by an electric motor 3 is known.

The fan 2 for the blower and the electric motor 3 are connected, for example, as shown in FIG. Specifically, the thin plate-shaped fan body 4 and the fan boss 5 are fixed with rivets 6, the motor shaft 8 is passed through the through hole 7 of the fan boss 5, the fan fixing screw 9 is screwed, and the fan The stopper 10 stops the rotation. The motor shaft 8 is in a state of uniformly contacting the inner surface of the through hole 7 of the fan boss 5 and functions as a guide portion of the motor shaft 8 so that the center of the motor shaft 8 and the center of the fan 2 for the blower coincide with each other. doing.

In the above-described blower, when the power supply to the electric motor 3 is started, the coil wound in the electric motor 3 is supplied with electricity, and the magnetic force generated there is used to apply the electric power to the rotor (rotor) attached to the motor shaft 8. 2), the motor shaft 8 is rotated, and thereby the fan 2 for the blower is rotated. Electromagnetic noise is generated by energizing the coil of the electric motor in this manner. The electromagnetic noise is caused by vibration, and the vibration generated by the coil is transmitted to the fan boss portion 5 via the motor shaft 8, and finally, the respective components such as the fan body 4 and the fan plate 11 vibrate. And generate noise.

In order to solve this problem, a rubber bush and a rubber sheet are provided between the fan body 4 and the fan boss 5 as shown in FIG. 3 or between the fan boss 5 and the fan fixing screw 9 as shown in FIG. The vibration propagated from the motor shaft 8 is fixed through the elastic body 12 such as
2 to prevent the generation of noise due to vibration.

[0006]

SUMMARY OF THE INVENTION As described above, the elastic member 1
If the vibrations are absorbed in step 2 to prevent the generation of noise due to the vibrations, it is difficult to maintain the performance of absorbing vibrations for a long time due to a decrease in the vibration absorbing power due to the deterioration of the elastic body 12 itself. In this case, oil generated and adhered by cooking adheres to the elastic body 12, or when a detergent used for cleaning by a user adheres to the elastic body 12, it is denatured and hardened, so that the vibration absorbing power is reduced. Although there are elastic bodies that can endure these things, they are very expensive and lead to an increase in cost.

In the structure shown in FIG. 3, it is very difficult to select the strength at the time of caulking (fixing) the fan body 4 and the fan boss 5, and in the structure shown in FIG. Is too strong, the vibration absorbing effect of the elastic body 12 cannot be obtained. If the strength is insufficient, the swing of the fan 2 for the blower may increase, or the fan 2 for the blower may fall off due to looseness. In particular, the structure shown in FIG. 4 is a part to be removed by the user at the time of cleaning, and a method of tightening at the time of assembling after cleaning (too tight or too loose).
In some cases, the vibration absorbing effect of the elastic body 12 is not exhibited at all.

Accordingly, an object of the present invention is to provide a connection structure between a blower fan and a motor shaft which can solve the above-mentioned problems.

[0009]

According to a first aspect of the present invention, there is provided a fan for a blower in which a fan boss portion 5 is attached to a fan body 4 and a motor shaft 8 is inserted and connected into a through hole 7 of the fan boss portion 5. In the motor shaft coupling structure, a contact area between the through hole 7 and the motor shaft 8 is reduced by preventing a part of the through hole 7 from contacting a part of the motor shaft 8 and leaving the other part out of contact. And a connection structure of a fan for a blower and a motor shaft.

In the second invention, the through hole 7 of the fan boss 5 is provided.
A plurality of protruding pieces 20 and 22 that are in contact with the outer peripheral surface of the motor shaft 8 and one of the inner peripheral surfaces of the through holes 7 are provided on the inner peripheral surface of the motor shaft 8 and one of the outer peripheral surfaces thereof at intervals in the circumferential direction. This is a connection structure between the fan for the blower and the motor shaft, which is provided continuously in the direction and has a small contact area between the through hole 7 and the motor shaft 8.

A third aspect of the present invention is directed to a through hole 7 of a fan boss 5.
Circumferential grooves 21 and 23 are sequentially formed in the longitudinal direction on one of the inner peripheral surface of the motor shaft 8 and the outer peripheral surface of the motor shaft 8.
23 so that the remaining portion other than 23 contacts one of the outer peripheral surface of the motor shaft 8 and the inner peripheral surface of the through hole 7.
The structure of the connection between the fan for the blower and the motor shaft in which the contact area between the fan and the motor shaft 8 is reduced.

[0012]

According to the first aspect of the invention, the contact area between the motor shaft 8 and the through hole 7 of the fan boss 5 is small, and the propagation of electromagnetic vibration generated by energizing the electric motor and transmitted from the motor shaft 8 to the fan boss 5 is achieved. Since the efficiency is reduced and the electromagnetic vibration transmitted to the fan body and the like is very small, noise due to the vibration of the fan for the blower can be prevented.

Further, since no elastic material is used, there is no change in the vibration reducing effect even when used for a long time.
Even if the user removes the blower fan 2 at the time of cleaning, it can be easily assembled again after cleaning, so that the vibration reduction performance can be permanently maintained.

Moreover, since a part of the through-hole 7 of the fan boss 5 and a part of the motor shaft 8 are in contact with each other, the fan boss serves as a guide between the fan body and the motor shaft. The fan and the motor shaft 8 can be aligned.

According to the second invention, the plurality of projecting pieces 20, 2
Since 2 contacts one of the outer peripheral surface of the motor shaft 8 and the inner peripheral surface of the through hole 7, it sufficiently fulfills the role of the original guide of the fan boss portion, and the fan for the blower and the motor shaft 8 can be precisely aligned.

According to the third aspect, the fan boss portion 5
And the outer peripheral surface of the motor shaft 8 and the inner peripheral surface of the through hole 7 in contact with a plurality of longitudinal portions of one of the motor shaft 8. And the motor shaft 8 can be accurately aligned with the fan for the blower.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. 5, 6, and 7. FIG. The same members as those in the related art have the same reference numerals. The inner diameter of the through hole 7 of the fan boss portion 5 is made larger than the outer diameter of the motor shaft 8, and a plurality of protruding pieces 20 are continuously formed on the inner surface of the through hole 7 at equal intervals in the circumferential direction over the entire length in the longitudinal direction. To be provided. The protruding length of the protruding piece 20 is half of the difference between the inner diameter of the through hole 7 and the outer diameter of the motor shaft 8, and the inner diameter of a virtual circular locus connecting the protruding end faces of the plurality of protruding pieces 20 is the outer diameter of the motor shaft 8. Is the same as The four protruding pieces 20 are provided at intervals of 90 degrees.
There may be three at 20 ° intervals, or five or more.

The fan boss portion 5 having the plurality of projecting pieces 20 can be easily manufactured by casting as in the prior art.
Since the number of components does not increase compared with the conventional fan boss portion 5, it can be manufactured at low cost.

As shown in FIG. 7, the through hole 7 and the outer peripheral surface of the motor shaft 8 do not come into contact with each other as shown in FIG.
Since 0 contacts the outer peripheral surface of the motor shaft 8, the contact area between the fan boss 5 and the motor shaft 8 is extremely small.

For this reason, the propagation efficiency of the electromagnetic vibration generated by energization of the electric motor and transmitted from the motor shaft 8 to the fan boss portion 5 decreases, and the fan body 4 and the fan blade 1
Since the electromagnetic vibration that propagates to each part such as 1 becomes extremely small, it is possible to prevent noise generation due to the vibration of the fan 2 for the blower.

Further, even if it is not necessary to use an elastic body such as a rubber sheet as in the prior art, the same degree of vibration reduction effect can be obtained, and the vibration reduction effect does not change at all even when used for a long time. Even if the user removes it during cleaning, it can be easily assembled again after cleaning, so that it is possible to maintain excellent vibration reduction performance permanently.

The plurality of projections 20 and the motor shaft 8
Contacting the outer peripheral surface of the motor shaft 8 so as to sufficiently serve as a guide between the fan main body 4 and the motor shaft 8,
The center of the motor shaft 8 and the center of the fan boss portion 5 match, and the motor shaft 8 and the fan 2 for the blower can be aligned.

Next, a second embodiment of the present invention will be described with reference to FIGS. The inner diameter of the through hole 7 of the fan boss portion 5 and the outer diameter of the motor shaft 8 are the same, and the through hole 7
A circumferential groove 21 is sequentially formed in the longitudinal direction. For example, a spiral groove having a V-shaped cross section is formed.

In this way, the remaining small portion other than the groove 21 in the through hole 7 of the fan boss portion 5 comes into contact with the outer peripheral surface of the motor shaft 8, so that the contact area is reduced as in the above-described embodiment. Since the propagation efficiency of electromagnetic vibration generated by energization of the electric motor is reduced, and the electromagnetic vibration propagated to each part such as the fan body 4 and the fan blade 11 becomes extremely small, noise generated by the vibration of the fan 2 for the blower is reduced. Can be prevented.

Further, since the remaining portion of the through hole 7 is present over the entire length in the longitudinal direction, it sufficiently serves as a guide, and the fan 2 for the blower and the motor shaft 8 can be aligned.

The above-mentioned spiral groove can be easily formed by manufacturing the fan boss part 5 by casting or the like and then threading the inner surface of the through hole 7.

Next, a third embodiment of the present invention will be described with reference to FIG. The outer diameter of the portion 8a of the motor shaft 8 to be inserted into the through hole 7 of the fan boss 5 is
And a plurality of protruding pieces 22 are provided integrally and continuously in the longitudinal direction at equal intervals in the circumferential direction on the portion 8a.

The outer diameter of the virtual circular locus connecting the protruding end faces of the plurality of protruding pieces 22 is the same as the inner diameter of the through-hole 7, and the protruding end faces of the plurality of protruding pieces 22 contact the inner surface of the through-hole 7. The contact area between the motor shaft 8 and the through hole 7 is reduced without contacting the portions.

In this way, the noise caused by the vibration of the fan 2 for the blower can be reduced, and the fan 2 for the blower and the motor shaft 8 can be aligned like the first embodiment.

In this case, the motor shaft 8 is
And a portion 8a to be inserted into the through hole 7 is cut to form a motor shaft having a protruding piece 22.

Next, a fourth embodiment of the present invention will be described with reference to FIG.
It will be described based on. The outer diameter of the motor shaft 8 is the same as the inner diameter of the through hole 7 of the fan boss 5, and circumferential grooves 23 are sequentially formed in the longitudinal direction in the portion 8 a to be inserted into the through hole 7. For example, a spiral groove is formed.

In this way, as in the second embodiment, the contact area between the motor shaft 8 and the through hole 7 is reduced, so that noise due to the vibration of the fan 2 can be reduced. The motor shaft 8 can be centered.

The formation of the spiral groove in the portion 8a to be inserted into the through hole 7 of the motor shaft 8 is performed when the screw portion 24 into which the fan fixing screw 9 is screwed is formed at the tip of the motor shaft 8. Since the portion 24 may be formed to be extended, the manufacture is easy.

The above-mentioned groove 21 and groove 23 may be formed in a ring shape at intervals in the longitudinal direction.
Inner peripheral surface of through hole 7 of fan boss 5 and motor shaft 8
The contact area may be reduced by forming a knurl groove on one of the outer peripheral surfaces of. In each embodiment, the sirocco fan has been described. However, it is needless to say that the present invention can be applied to a propeller fan and a turbo fan.

[0035]

According to the first aspect of the present invention, the contact area between the motor shaft 8 and the through hole 7 of the fan boss portion 5 is small, and the electromagnetic force generated by energizing the electric motor and transmitted from the motor shaft 8 to the fan boss portion 5 is obtained. Vibration propagation efficiency decreases,
Since the electromagnetic vibration transmitted to the fan body and the like is very small, noise due to the vibration of the fan for the blower can be prevented.

Further, since no elastic material is used, there is no change in the vibration reducing effect even when used for a long time.
Even if the user removes the blower fan 2 at the time of cleaning, it can be easily assembled again after cleaning, so that the vibration reduction performance can be permanently maintained.

Moreover, since a part of the through hole 7 of the fan boss 5 and a part of the motor shaft 8 are in contact with each other, the fan boss serves as an original guide for the fan body and the motor shaft, and is used for the blower. The fan and the motor shaft 8 can be aligned.

According to the second aspect of the present invention, the plurality of projecting pieces 20 and 22 come into contact with one of the outer peripheral surface of the motor shaft 8 and the inner peripheral surface of the through hole 7, so that the fan boss portion serves as an original guide. And the motor shaft 8 can be accurately aligned with the fan for the blower.

According to the third aspect of the present invention, the outer peripheral surface of the motor shaft 8 and the through-hole 7 are formed in a plurality of longitudinal portions of one of the through-hole 7 of the fan boss 5 and the motor shaft 8.
Since it contacts a plurality of portions in the longitudinal direction of the inner peripheral surface of the fan, the original function of the fan boss portion is sufficiently fulfilled, and the fan for the blower and the motor shaft 8 can be accurately aligned.

[Brief description of the drawings]

FIG. 1 is a front view of a blower.

FIG. 2 is a cross-sectional view showing a conventional example of a connection portion between a fan for a blower and a motor shaft.

FIG. 3 is a cross-sectional view showing an example in which noise due to vibration is prevented by a conventional elastic body.

FIG. 4 is a cross-sectional view showing another example in which noise due to vibration is prevented by a conventional elastic body.

FIG. 5 is an exploded perspective view showing the first embodiment of the present invention.

FIG. 6 is a plan view of a fan boss.

FIG. 7 is a sectional view of a connected state.

FIG. 8 is an exploded perspective view showing a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a connected state.

FIG. 10 is an exploded perspective view showing a third embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a connection state according to a fourth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Blower case, 2 ... Blower fan, 3 ... Electric motor, 4 ... Fan body, 5 ... Fan boss, 6 ... Rivets, 7 ... Through hole, 8 ... Motor shaft, 9 ... Fan fixing screw, 10 ... Rotation Stop, 11 ... fan blade, 12 ...
Elastic body, 20 ... projecting piece, 21 ... groove, 22 ... projecting piece, 23 ...
groove.

Claims (3)

[Claims] 1. A connection structure between a fan for a blower and a motor shaft, wherein a fan boss portion 5 is attached to a fan body 4 and a motor shaft 8 is inserted and connected into a through hole 7 of the fan boss portion 5. 7. A connection between a fan for a blower and a motor shaft, wherein a contact area between the through hole 7 and the motor shaft 8 is reduced by making a part of the motor shaft 8 contact with a part of the motor shaft 8 but not the other part. Construction. 2. A plurality of projections which are in contact with one of the inner peripheral surface of the through hole 7 of the fan boss 5 and the outer peripheral surface of the motor shaft 8 and one of the outer peripheral surface of the motor shaft 8 and the inner peripheral surface of the through hole 7. 2. The structure for connecting a fan for a blower and a motor shaft according to claim 1, wherein the pieces 20, 22 are continuously provided in the longitudinal direction at intervals in the circumferential direction to reduce the contact area between the through hole 7 and the motor shaft 8. 3. One of the inner peripheral surface of the through hole 7 of the fan boss portion 5 and the outer peripheral surface of the motor shaft 8 has grooves 21 and 2 in the circumferential direction.
3 are sequentially formed in the longitudinal direction, and the remaining portions other than the grooves 21 and 23 are brought into contact with one of the outer peripheral surface of the motor shaft 8 and one of the inner peripheral surfaces of the through hole 7. The connecting structure of a fan for a blower and a motor shaft according to claim 1, wherein the contact area is reduced.