JP2013245626A - Air fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air fan used in a combustion device for burning fuel gas, without increasing noise even by long-term use.SOLUTION: A rotary shaft of a motor is inserted into an installation hole of a substrate in a state of sandwiching the substrate of a rotary blade part by rubber members from both surface sides, and the substrate is fastened by a screw to the rotary shaft by including the rubber members by using a nut. At this point, a metallic spring is inserted between the nut and the rubber member. Thus, even if a permanent set is caused in the rubber member, the permanent set can be absorbed by restoration of the metallic spring. Therefore, the substrate can be pressed by proper force by the rubber members, and looseness of the rotary blade part can be restrained. As a result of it, an increase in the noise of the air fan by the long-term use can be avoided.

Description

  The present invention relates to a blower fan used in a combustion apparatus that burns fuel gas.

  A blower fan is used for various purposes in a combustion apparatus that burns fuel gas. For example, in a combustion apparatus used as a water heater, a blower fan is used for the purpose of supplying combustion air to a burner. In addition, the combustion device used as a warm air heater has a warm air generated for the purpose of diluting the combustion exhaust generated by the combustion of fuel gas with air and blowing out the warm air, or by warming the air with the combustion exhaust. A blower fan is used for the purpose of blowing out air.

  In these ventilation fans, it blows by rotating a rotary blade using a motor. Here, although the rotation shaft of the motor is slight, vibration in the axial direction occurs during rotation. And if this vibration is transmitted to the rotary blade, it may cause noise. In view of this, there has been proposed a blower fan having a structure in which both sides of a portion where the rotating shaft is inserted into the rotating blades are sandwiched by vibration-proof rubber, and the rotation spring together with the vibration-proof rubber is attached to the rotating shaft using a nut (Patent Literature). 1).

JP 2003-161293 A

  However, the air blowing fan having the proposed structure has a problem that noise may increase due to long-term use. This is because a large compressive force is applied to the anti-vibration rubber when tightened with a nut, and the force (pressing force) to press the rotating blades weakens due to the anti-vibration rubber sag due to long-term use. As a result, rattling occurs between the rotating shaft of the motor and the rotating blade.

  The present invention has been made in response to the above-mentioned problems of the prior art, and is used in a combustion apparatus that burns fuel gas, and provides a blower fan that does not increase noise even when used for a long time. With the goal.

In order to solve the above-described problems, the blower fan of the present invention employs the following configuration. That is,
In a blower fan that is used in a combustion device that burns fuel gas and has a rotating blade portion that blows air by rotating and a motor that rotates the rotating blade portion,
The rotating blade part is
A substrate having a mounting hole through which the rotation shaft of the motor is inserted;
A rubber member provided by sandwiching the place where the mounting hole of the substrate is formed from both sides, and
The rotating shaft is inserted through the mounting hole, and the substrate is attached by screwing the substrate together with the rubber member to the rotating shaft using a nut.
A metal spring that absorbs the sag of the rubber member is provided between the nut and the rubber member.

  In the blower fan of the present invention, when the rotating blade portion is attached to the rotating shaft of the motor by tightening the nut, not only the rubber members provided on both sides of the substrate are compressed, but also the metal spring is compressed. It becomes a state. For this reason, even if the rubber member sags due to the long use of the blower fan, the rubber member can be pressed against the substrate by the restoring force of the compressed metal spring. The “sagging of the rubber member” refers to permanent distortion generated in the rubber member by receiving a force for a long time. As a result, rattling does not occur between the rotary blade portion and the rotating shaft of the motor, and it is possible to avoid an increase in noise of the blower fan.

  Further, since the metal spring is provided between the nut and the rubber member, even when the nut is strongly tightened, the metal spring is compressed, so that the rubber member is excessively deformed and a large compressive force is applied. Absent. For this reason, it is possible to prevent the rubber member from undergoing sag due to a large compressive force.

  In addition, examples of the “blower fan used in the combustion apparatus” include a combustion fan that supplies combustion air to the burner of the combustion apparatus, and a blower that blows hot air generated by diluting the combustion exhaust of the burner with air. Examples thereof include a fan and a warm air fan that blows warm air generated by warming air with combustion exhaust.

  In the above-described blower fan of the present invention, the metal spring may be constituted by a coil spring provided coaxially with the rotating shaft.

  If a coil spring is used, the amount of compression of the metal spring can be sufficiently increased. For this reason, even if the metal spring expands by the amount of the sag of the rubber member, it can be in a state where it has only expanded at a slight ratio from the amount of compression of the metal spring at the time of attachment. Then, even if the metal spring is stretched due to the sag of the rubber member, it is possible to prevent the force for pressing the rubber member against the substrate from almost decreasing.

  In addition, if the metal spring is configured using a coil spring, an effect of preventing an excessive compressive force from being applied to the rubber member when the nut is tightened can be obtained. That is, the amount of compression of the metal spring can be made sufficiently large, so that even if the amount of compression increases somewhat, the force with which the metal spring presses the rubber member can be hardly increased. For this reason, even when the nut is strongly tightened, it is possible to prevent an excessive compressive force from being applied to the rubber member.

  In the above-described blower fan of the present invention, a metal spring may be configured by stacking a plurality of disc springs in the axial direction of the rotation shaft.

  If a disc spring is used, the metal spring can be made small, and if a plurality of disc springs are stacked, a sufficient stroke can be secured as a whole. For this reason, it is possible to absorb the sag of the rubber member, and at the same time, it is possible to prevent an excessive compressive force from being applied to the rubber member when the nut is tightened.

It is an exploded view of the ventilation fan 1 of a present Example. It is sectional drawing which shows the structure of the ventilation fan 1 of a present Example. It is explanatory drawing which showed the reason which noise increases by long-time use with the conventional ventilation fan 1. FIG. It is explanatory drawing which showed the reason which can avoid the increase in noise even if it uses for a long time with the ventilation fan 1 of a present Example. FIG. 6 is an enlarged cross-sectional view of a portion where a substrate 12 of a rotating blade portion 10 of a modification is attached to a rotating shaft 22 of a motor 20.

  FIG. 1 is an exploded view of the blower fan 1 of this embodiment. Moreover, FIG. 2 is sectional drawing which shows the structure of the ventilation fan 1 of a present Example. As shown in the figure, the blower fan 1 includes a rotary blade unit 10, a motor 20 that rotates the rotary blade unit 10, and the like. In the present embodiment, the rotary blade 10 is described as a so-called sirocco fan, but other types of fans may be used.

  In the rotary blade portion 10 of this embodiment, a plurality of blade pieces 11 that are elongated in the axial direction of the rotary shaft 22 of the motor 20 are erected on the outer edge portion of the substantially circular substrate 12. A mounting hole 13 through which the rotating shaft 22 of the motor 20 is inserted is formed at the center of the substrate 12, and the plurality of blade pieces 11 are arranged radially with respect to the mounting hole 13 at a predetermined interval. When the motor 20 is driven to rotate the rotary blade portion 10, air can be blown in the circumferential direction from between the plurality of blade pieces 11.

  The rotating shaft 22 of the motor 20 has a large-diameter portion (mounting portion 22a) provided on the proximal end side and a small-diameter portion (fastening portion 22b) provided on the distal end side. A male screw is formed on the outer peripheral side surface. In addition, the fastening portion 22b is formed in a so-called D-cut shape in which a part of the outer peripheral side surface is cut flat, and correspondingly, the shape of the mounting hole 13 of the substrate 12 through which the rotary shaft 22 is inserted. Is also formed in a D-shape.

  When assembling the blower fan 1, first, a metal flat plate washer 15 formed in an annular shape and an anti-vibration rubber 14 formed in an annular shape having the same diameter as the washer 15 are sequentially formed. Fit on the rotating shaft 22. The inner diameter of the washer 15 is larger than the outer diameter of the fastening portion 22b of the rotating shaft 22, and smaller than the outer diameter of the mounting portion 22a. The washer 15 fitted to the rotating shaft 22 is attached to the mounting portion 22a. Placed on top. The anti-vibration rubber 14 of this embodiment corresponds to the “rubber member” of the present invention.

  Subsequently, after the fastening portion 22b of the rotating shaft 22 is inserted into the mounting hole 13 formed in the substrate 12 of the rotating blade portion 10, the second vibration isolating rubber 14 and the second washer 15 are further connected to the mounting hole 13 of the rotating blade portion 10. It fits in the fastening part 22b in order. Since the fastening portion 22b of the rotating shaft 22 is formed in a D-cut shape, and the mounting hole 13 of the substrate 12 is also formed in a D shape, the rotating blade portion 10 may idle when the rotating shaft 22 rotates. Absent. Thereafter, the coil spring 30 is placed on the washer 15, and the nut 16 is fastened to the fastening portion 22 b of the rotating shaft 22. At this time, the coil spring 30 is sandwiched between the nut 16 and the washer 15 and compressed as shown in FIG. The coil spring 30 of this embodiment corresponds to the “metal spring” of the present invention.

  In the blower fan 1 of this embodiment having such a configuration, the force when the nut 16 is fastened to the fastening portion 22b is not directly applied to the vibration isolating rubber 14, but is a coil spring interposed between the nut 16 and the washer 15. The anti-vibration rubber 14 is added via 30. For this reason, noise does not become large even if it is used for a long time. The reason for this will be described below. As a preparation for this, when the tightening force of the nut 16 is directly applied to the vibration isolating rubber 14 (when the coil spring 30 is not interposed between the nut 16 and the washer 15), the reason is long. The reason why the noise may increase due to the use of is described.

  FIG. 3 is an explanatory view showing the reason why noise increases due to long-term use of the conventional blower fan 1. FIG. 3A shows an enlarged cross-sectional view of a mounting portion between the substrate 12 of the rotary blade 10 and the rotating shaft 22 of the motor 20 in the conventional blower fan 1. As shown in the drawing, the conventional blower fan 1 is not provided with a coil spring 30. For this reason, when the nut 16 is fastened to the rotating shaft 22, the nut 16 deforms the vibration isolating rubber 14 via the washer 15, and the substrate 12 is held by the restoring force of the deformed vibration isolating rubber 14.

  Here, in general, when a long time elapses in a state in which the rubber material is deformed by receiving a force, a permanent distortion is generated by creep, and the rubber material has a property that cannot be restored even if the force is removed. When permanent deformation (so-called “sagging”) is generated in the vibration isolating rubber 14 in a state of being deformed by the force from the nut 16, the force with which the vibration isolating rubber 14 holds the substrate 12 rapidly decreases. This is because the rubber material has a large elastic modulus.

  FIG. 3B shows the relationship between the amount of deformation (compression amount) of the vibration-proof rubber 14 by tightening the nut 16 and the force (holding force) that the vibration-proof rubber 14 holds the substrate 12. . The amount of compression of the anti-vibration rubber 14 corresponds to the rotation angle (tightening angle) when the nut 16 is tightened. Therefore, in FIG. 3B, the compression of the anti-vibration rubber 14 depends on the tightening angle of the nut 16. Represents quantity. Since the rubber material has a large elastic coefficient, if the tightening angle of the nut 16 (the amount of compression of the vibration isolating rubber 14) is increased, the restoring force of the vibration isolating rubber 14 increases abruptly. The force increases rapidly. However, if a slight sag occurs in the anti-vibration rubber 14, it will be in the same state as it was not compressed, and the restoring force of the anti-vibration rubber 14 will drop rapidly. As a result, as shown in FIG. 3B, the holding force of the substrate 12 is also rapidly reduced, and the rotary blade portion 10 may be rattled.

  FIG. 3C illustrates the difference in noise due to the presence or absence of sag. The solid line in the figure represents the noise of the blower fan 1 when measured without a sag, and the broken line in the figure represents the noise when measured with a sag. As is apparent from the measurement results, when the anti-vibration rubber 14 sags, the holding force of the substrate 12 decreases and noise increases.

  On the other hand, in the blower fan 1 of this embodiment, the coil spring 30 is provided between the nut 16 and the vibration isolating rubber 14. For this reason, when the nut 16 is tightened, the coil spring 30 is compressed, and the compressed coil spring 30 compresses the anti-vibration rubber 14. The compressed anti-vibration rubber 14 holds the substrate 12. As a result, the relationship between the tightening angle of the nut 16 and the holding force of the substrate 12 is significantly different from the relationship shown in FIG.

  FIG. 4 shows the relationship between the tightening angle of the nut 16 in the blower fan 1 of the present embodiment and the force (holding force) at which the anti-vibration rubber 14 holds the substrate 12. As described above, since the nut 16 compresses the coil spring 30 and the vibration isolating rubber 14, the tightening angle of the nut 16 corresponds to the compression amount of the vibration isolating rubber 14 and the coil spring 30. Since the elastic coefficient of the coil spring 30 (that is, the spring constant) is smaller than the elastic coefficient of the anti-vibration rubber 14, even if the tightening angle of the nut 16 (the compression amount of the anti-vibration rubber 14 and the coil spring 30) is increased. The force with which the coil spring 30 presses the anti-vibration rubber 14 against the substrate 12 does not change greatly. Therefore, the force (holding force) for holding the substrate 12 by the anti-vibration rubber 14 does not change greatly. For this reason, even if the anti-vibration rubber 14 sags, the holding force of the substrate 12 is not greatly reduced, and the substrate 12 can be held with an appropriate force. As a result, it is possible to avoid an increase in noise even when the blower fan 1 is used for a long time.

  In addition, since the coil spring 30 is compressed even if the nut 16 is strongly tightened, an excessive compressive force is not applied to the anti-vibration rubber 14. For this reason, since high accuracy is not required for tightening the nut 16, the blower fan 1 can be assembled easily and quickly.

  The following modifications are also present in the blower fan 1 of the present embodiment described above. In the following, modifications will be described focusing on differences from the above-described embodiment. In the description of the modification, the same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 5 is an enlarged cross-sectional view of a portion where the substrate 12 of the rotating blade portion 10 of the modified example is attached to the rotating shaft 22 of the motor 20. As shown in the drawing, in the modified example, instead of the coil spring 30 of the above-described embodiment, a plurality of ring-shaped (two in the illustrated example) disc springs 32 are stacked and the nut 16 and the washer 15 are overlapped. Is inserted between. The plurality of disc springs 32 of the modification corresponds to the “metal spring” of the present invention.

  Since the disc spring 32 is smaller than the coil spring 30, a portion for attaching the rotary blade portion 10 to the rotary shaft 22 of the motor 20 does not increase. Further, if a plurality of disc springs 32 are overlapped, a sufficient stroke can be secured, so that the same effect as in the above-described embodiment using the coil spring 30 can be obtained. When stacking a plurality of disc springs 32, as illustrated in FIG. 5, the disc springs 32 may be alternately stacked back to back, or the widened sides of the disc springs 32 face each other. A plurality of disc springs 32 may be overlapped. Of course, it is not necessary to superimpose the disc springs 32 so that they are staggered. For example, a washer may be provided between the disc springs 32 and the disc springs 32 so that a plurality of disc springs 32 are stacked in the same direction. good.

  Although the blower fan 1 according to the present embodiment and the modification has been described above, the present invention is not limited to the above-described embodiment and the modification, and can be implemented in various modes without departing from the gist thereof. It is.

  For example, in the above-described embodiment, the rotary blade portion 10 is a sirocco fan, but the rotary blade portion 10 is not limited to this as long as it can blow air by rotating. For example, a so-called propeller fan in which a plurality of blades are attached radially about the rotation shaft 22 may be used.

DESCRIPTION OF SYMBOLS 1 ... Blower fan, 10 ... Rotary blade part, 11 ... Wing piece,
12 ... Substrate, 13 ... Mounting hole, 14 ... Anti-vibration rubber,
15 ... Washer, 16 ... Nut, 20 ... Motor,
22 ... Rotating shaft, 30 ... Coil spring, 32 ... Disc spring

Claims (3)

In a blower fan that is used in a combustion device that burns fuel gas and has a rotating blade portion that blows air by rotating and a motor that rotates the rotating blade portion,
The rotating blade part is
A substrate having a mounting hole through which the rotation shaft of the motor is inserted;
A rubber member provided by sandwiching the place where the mounting hole of the substrate is formed from both sides, and
The rotating shaft is inserted through the mounting hole, and the substrate is attached by screwing the substrate together with the rubber member to the rotating shaft using a nut.
A blower fan, wherein a metal spring that absorbs the sag of the rubber member is provided between the nut and the rubber member. The blower fan according to claim 1,
The blower fan, wherein the metal spring is a coil spring provided coaxially with the rotation shaft. The blower fan according to claim 1,
The blower fan, wherein the metal spring is a plurality of disc springs stacked in the axial direction of the rotating shaft.

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