JP3772609B2 - Fan holding structure, blower and refrigerator-freezer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain generation of abnormal sound from a fan by stabilizing the natural frequency of the fan, concerning a fan holding structure. SOLUTION: A rotary shaft of a fan motor and a shaft for holding the fan are provided inside and outside a boss of the fan, the rotary shaft of the fan motor and the shafts inside and outside the boss are fastened at least each one part by springs and held.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fan holding structure, a blower, and a refrigerator-freezer, and more particularly to a fan resonance prevention structure.
[0002]
[Prior art]
As an example of the prior art, FIG. 6 is a view showing a fan, and FIG. 7 is a view showing a holding structure with a rotating shaft of a fan motor.
In FIGS. 6 and 7, the boss of the fan is shown as a partially cut view for explanation.
6 and 7, reference numeral 10 denotes a fan, and reference numeral 2 denotes a boss of the fan 10, which has a shaft 3 for holding a rotating shaft inside. Reference numeral 5 denotes a fan motor, and 6 denotes a rotation shaft of the fan motor 5, which is inserted into the shaft 3 of the boss 2. Reference numeral 7 denotes a spring for fastening the rotating shaft 6 of the fan motor 5 and the shaft 3 inside the boss 2 of the fan 10.
As described above, conventionally, the holding structure is such that the rotating shaft 6 and the fan 10 of the fan motor 5 are clamped and held by the spring 7 at only one position of the shaft 3 inside the boss 2 of the fan 10.
[0003]
In the above structure, when the fan motor 5 is driven, the fan motor 5 becomes a vibration source, and resonance occurs when the frequency of vibration transmitted through the rotation shaft 6 of the fan motor 5 matches the eigenvalue of the fan 10. The eigenvalue of the fan 10 is determined by the inertia of the fan 10, resilience, and boundary conditions. Further, the vibration of the fan motor 5 is transmitted to the fan 10 from the contact point between the fan 10 and the rotating shaft 6 of the fan motor 5. Usually, in order to avoid resonance between the eigenvalue of the fan 10 and the vibration transmitted from the rotating shaft 6 of the fan motor 5, the rotational speed of the fan motor 5 is changed.
[0004]
FIG. 8 is a cross-sectional view of a main part showing an insertion part of the rotating shaft 6 in FIG. 7 into the boss 2 of the fan 10. Since the boss 2 of the fan 10 and the rotating shaft 6 of the fan motor 5 are usually made of different materials, the expansion rate and contraction rate differ depending on the temperature, and the boss 2 of the fan 10 and the rotating shaft 6 of the fan motor 5 are different. The gap 9 changes depending on the temperature, and the boundary condition between the fan 10 and the rotating shaft 6 of the fan motor 5 changes. Therefore, the eigenvalue of the fan 10 changes greatly. Therefore, even if the number of rotations of the fan motor 5 is changed, the resonance between the vibration transmitted from the rotation shaft 6 of the fan motor 5 and the eigenvalue of the fan 10 or the vibration generated by cogging of the fan motor 5 and the eigenvalue of the fan 10 Therefore, the possibility of abnormal noise was high. The cogging is a fluctuation in the torque of the fan motor 5, and the abnormal noise is a sound in which a sound in a specific frequency region is greatly projected at 300 Hz or more.
[0005]
FIG. 9 shows an example of a block diagram showing feedback control for changing the rotational speed of the fan motor. Even if the rotation speed of the fan motor 5 is controlled by feedback control in which the output voltage of the fan motor 5 is observed and a feedback voltage is applied to the input voltage to the fan motor 5 so as to reach the target rotation speed, it is shown in FIG. As described above, since the eigenvalue of the fan 10 changes greatly due to the change in the gap 9 between the shaft 3 of the boss 2 of the fan 10 and the rotating shaft 6 of the fan motor 5, the eigenvalue of the fan 10 and the vibration transmitted from the rotating shaft 6 of the fan motor 5. , Or the resonance of the eigenvalue of the fan 10 and the vibration generated by the cogging of the fan motor 5 transmitted from the rotating shaft 6 of the fan motor 5 occurred, and there was a high possibility of occurrence of abnormal noise.
[0006]
FIG. 10 is a cross-sectional view of an essential part showing a conventional fan mounting structure disclosed in Japanese Patent Laid-Open No. 9-310698. The rotating shaft 23 of the electric motor 22 is inserted into the boss 21 of the fan 20, one of the rotating shafts 23 is fastened by a nut 24, and the other is connected to the outer peripheral portion of the boss 21 and the outer peripheral portion of the rotating shaft 23 adjacent thereto. After covering with the heat shrinkable tube 25, the boss 21 is heated and fixed to the rotating shaft 23.
[0007]
[Problems to be solved by the invention]
As described above, conventionally, the holding force is weak because of the holding structure in which the rotating shaft of the fan motor and the fan are clamped and held at only one of the inner shafts of the boss. The characteristic value of the fan changes greatly due to a change in the clearance with the rotation axis of the fan motor, so even if the number of rotations is changed, the vibration of the fan motor transmitted through the rotation axis of the fan motor and the resonance of the characteristic value of the fan, or the fan motor There is a problem that abnormal noise occurs due to the resonance between the vibration generated by cogging and the eigenvalue of the fan.
[0008]
Further, according to the conventional fan mounting structure shown in FIG. 10, the fan boss and the rotating shaft are fixed at two locations, one is fastened by a nut, and the other is the outer periphery of the rotating shaft adjacent to the outer peripheral portion of the boss. It is closely fixed with a heat shrinkable tube with the part. However, the fastening with one nut is in the axial direction, and the other heat-shrinkable tube is fixed in the centrifugal direction. Therefore, there is only one centrifugal direction and the holding force is insufficient.
[0009]
The present invention has been made to solve the above-described problems, and has a fan holding structure that stabilizes the eigenvalue of the fan by forming a stable boundary condition between the fan and the fan motor rotating shaft to be fitted. In addition, by stabilizing the eigenvalue of the fan, the resonance of the fan motor vibration transmitted through the rotation axis by the fan motor and the eigenvalue of the fan, or the vibration generated by cogging of the fan motor and the eigenvalue of the fan An object of the present invention is to provide a blower capable of avoiding the occurrence of abnormal noise from the fan and a low-noise refrigerator-freezer equipped with the blower.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a fan holding structure comprising: a boss that supports a fan blade; and a boss shaft portion that is integrally fixed to the boss and is fitted to a rotation shaft and transmits rotation of the rotation shaft to the blade. In the boss axis direction of the fan, there are provided a plurality of holding means for tightening and regulating the movement of the boss axis in the centrifugal direction.
[0011]
The fan holding structure according to claim 2 includes an inner portion in which the boss shaft portion is housed inside the boss, and an outer portion exposed to the outside of the boss, and the holding means is disposed on the inner side of the boss shaft. It is on the outside.
[0012]
In the fan holding structure according to claim 3, the holding means is a spring.
[0013]
The fan holding structure according to claim 4 has a slit in the holding means.
[0014]
Further, the fan holding structure described in claim 5 is configured to be held by screws as the holding means described in claim 1.
[0015]
The blower according to claim 6 includes a fan motor that rotationally drives a fan, and the fan holding structure according to any one of claims 1 to 5 is configured such that a rotation shaft of the fan motor is inserted into a boss of the fan. It is intended to be retained.
[0016]
According to a seventh aspect of the present invention, the number of revolutions is set so as to avoid the resonance between the vibration transmitted through the rotation axis of the fan motor and the eigenvalue of the fan, or the resonance between the vibration generated by cogging of the fan motor and the eigenvalue of the fan. A rotation speed setting means is provided.
[0017]
Moreover, the air blower according to claim 8 controls the number of rotations set by the rotation number setting means by using feedback control.
[0018]
The refrigerator-freezer according to claim 9 has a function of blowing cold air cooled by the cooler into the refrigerator-freezer, or a function of blowing air to the compressor outer portion in order to suppress an increase in the temperature of the compressor. In the refrigerator-freezer, the blower according to any one of claims 6 to 8 is mounted.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0020]
Embodiment 1 FIG.
1, 2 and 3 are views showing an example of an embodiment of the present invention, FIG. 1 is a view showing a fan, FIG. 2 is a view showing a holding structure with a rotating shaft of a fan motor, and FIG. 2 is a cross-sectional view of the main part showing a portion of the rotating shaft inserted into the boss of the fan in FIG. 2, and FIG. 1 and FIG. As shown in FIG. 2, a fan and a fan motor are combined to form a blower.
[0021]
In the figure, reference numeral 1 denotes a fan, and 2 denotes a boss of the fan 1, which has a shaft 3 and a shaft 4 that are integrally fixed to the inside and outside of the boss 2 and hold a rotating shaft. Reference numerals 7 and 8 denote springs for tightening the rotating shaft 6 of the fan motor 5 and the inner shaft 3 and the outer shaft 4 of the boss 2 of the fan 1, respectively. The inner shaft 3 and the outer shaft 4 of the boss 2 are each provided with two slits so as to be tightened by springs 7 and 8.
[0022]
The rotating shaft 6 of the fan motor 5 is passed through the holes of the inner shaft 3 and the outer shaft 4 of the boss 2, and the rotating shaft 6 and the inner shaft 3 and the outer shaft 4 of the boss 2 are respectively connected to a spring 7 and a spring 8. Tighten with and hold in two places. As described above, the rotation shaft 6 of the fan motor 5 inserted into the boss 2 of the fan 1 and the shaft of the boss 2 of the fan 1 are held at two or more locations of the shaft 3 and the shaft 4 of the boss 2. Thus, stable holding of the rotating shaft 6 of the fan motor 5 and the shaft 3 and shaft 4 of the boss 2 of the fan 1 can be obtained.
[0023]
Usually, the material of the rotating shaft 6 of the fan 1 and the fan motor 5 is different, and the shrinkage rate and the expansion rate are different depending on the temperature. However, as shown in the cross-sectional view of the main part of the rotating shaft shown in FIG. Since the rotary shaft 6 and the inner shaft 3 and the outer shaft 4 of the boss 2 are clamped by the spring 7 and the spring 8, respectively, and held at two locations, the fan motor 5 is also resistant to contraction and expansion due to temperature dependence. It is possible to obtain stable holding of the rotary shaft 6 and the shaft 3 and the shaft 4 of the boss 2 of the fan 1.
[0024]
With the holding structure as described above, the holding of the fan 1 and the rotating shaft 6 of the fan motor 5 is stabilized, whereby the eigenvalue of the fan 1 is stabilized, and the fan transmitted through the rotating shaft 6 of the fan motor 5 is stabilized. The number of rotations of the fan motor 5 that avoids resonance between the vibration of the motor 5 and the eigenvalue of the fan 1 or the vibration generated by cogging of the fan motor 5 and the eigenvalue of the fan 1 can be set. Generation of abnormal noise from the fan 1 can be suppressed. Here, holding stabilization means holding so that the eigenvalue of the fan does not change significantly by hardly changing the boundary condition between the fan and the fan motor, and stabilization of the eigenvalue of the fan hardly changes the eigenvalue of the fan. Say.
[0025]
The eigenvalue of the fan in the boundary condition in holding the fan and the fan motor rotating shaft at two or more locations of the fan shaft, and the boundary where the entire joint between the fan shaft and the fan motor rotating shaft is in close contact The characteristic value of the fan in the conditions is almost the same.
[0026]
In the above embodiment, the slits are provided in the shaft 3 and the shaft 4 of the boss 2 of the fan 1 and the holding structure with the rotating shaft 6 by tightening the spring 7 and the spring 8 is shown. 3 and the shaft 4 may be provided with screw holes, respectively, so as to hold the rotating shaft 6 by tightening screws.
[0027]
To remove the fan 1 from the rotating shaft 6 of the fan motor 5, the springs 7 and 8 may be removed and then removed, or the fan 1 may be pulled off from the rotating shaft 6 of the fan motor 5 without removing the spring. Good.
[0028]
The fan 1 of the above-described embodiment is formed by inserting and combining the rotating shaft 6 of the fan motor 5 with the fan 1, and the vibration of the fan motor 5 transmitted through the rotating shaft 6 of the fan motor 5 by driving the fan motor 5 and the fan 1. As a means for setting the rotational speed for avoiding resonance with the eigenvalue, when the frequency characteristics of the fan 1 are measured, the limited rotational speed range causing the resonance can be grasped. The number of revolutions can be set to avoid it.
[0029]
In addition, as a means for setting the rotation speed for avoiding resonance between the vibration generated by cogging of the fan motor 5 transmitted through the rotation shaft 6 of the fan motor 5 and the eigenvalue of the fan 1, the eigenvalue of the fan 1 is measured, and the fan motor is measured. After checking the number of poles of the stator and rotor of 5, (number of rotations of the fan motor 5) x (number of poles of the stator of the fan motor 5) x (number of poles of the rotor of the fan motor 5) ≠ (eigenvalue of the fan 1) The rotational speed of the fan motor 5 is preferably set so that
[0030]
Resonance between the vibration of the fan motor 5 transmitted through the rotating shaft 6 of the fan motor 5 and the eigenvalue of the fan 1, or the vibration generated by cogging of the fan motor 5 transmitted through the rotating shaft 6 of the fan motor 5 and the eigenvalue of the fan 1. In order to avoid this, the output rotational speed of the fan motor 5 is observed so that the rotational speed is set by the rotational speed setting means, and feedback control is applied to apply a feedback voltage to the input voltage to the fan motor 5. Control.
[0031]
Embodiment 2. FIG.
4 and 5 show the second embodiment. The fan 1 is formed by inserting the rotating shaft 6 of the fan motor 5 into the fan 1 described in the first embodiment of the present invention, and in this case, the blower 1a. 4 shows an example of a refrigerator-freezer equipped with a blower 1b. FIG. 4 is a simplified view of the refrigerator-freezer as viewed from the front, and FIG. 5 is a simplified view as viewed from the rear. In addition, since the air blower 1a and the air blower 1b are the same as that of Embodiment 1, description here is abbreviate | omitted. The arrows in FIG. 4 schematically show the air path.
[0032]
In the figure, 11 is a refrigerator-freezer, 12 is a cooler, 1a is a refrigerator compartment 13, an ice storage compartment 14, a temperature zone switching compartment 15, a vegetable compartment 16, a refrigerator compartment in which the refrigerator 11 has cold air cooled by the cooler 12. A blower that blows air to the chamber 17, 18 is a compressor, 1 b is a blower that blows air to the outer portion of the compressor 18 in order to suppress a temperature rise of the compressor 18, and 19 is a microcomputer mounted in the refrigerator 11. .
[0033]
The microcomputer 19 has a resonance between the vibration of the fan motor transmitted through the rotation axis of the fan motor of each of the fans 1a and 1b and the eigenvalue of the fan, or the resonance between the vibration generated by cogging of the fan motor and the eigenvalue of the fan. In order to avoid this, the rotational speed of the fan motor set by the rotational speed setting means described in the first embodiment is stored.
[0034]
The fan motor is controlled using feedback control so that the rotation speed of the fan motor for avoiding the resonance stored in the microcomputer 19 is set.
[0035]
【The invention's effect】
As described above, the fan holding structure according to the first aspect of the present invention includes the boss that supports the fan blades, and the boss shaft that is fixed to the boss and is fitted to the rotating shaft and transmits the rotation of the rotating shaft to the blade. And a plurality of holding means for tightening and restricting the movement of the boss shaft in the centrifugal direction in the boss axis direction of the fan, so that the fan holding structure can obtain a stable boundary condition in the centrifugal direction. It can be.
[0036]
According to a second aspect of the present invention, there is provided the fan holding structure including an inner portion in which the boss shaft portion is housed inside the boss and an outer portion exposed to the outside of the boss, and the holding means is located on the inner side and the outer side of the boss shaft. Therefore, the holding force can be increased by holding the boss shaft on the inside and outside of the boss shaft, and a fan holding structure can be obtained in which stable boundary conditions are obtained in the centrifugal direction and the axial direction.
[0037]
In the fan holding structure according to the third aspect, since the holding means is a spring, it can be easily clamped and held, and can be removed with a simple tool.
[0038]
In the fan holding structure according to the fourth aspect of the present invention, since the holding means has a slit, it can be easily clamped and held by a spring.
[0039]
Further, since the fan holding structure of claim 5 is held by tightening with a screw as the holding means of claim 1, it can be easily clamped and held in the same manner as holding by a spring, and also when being removed. This can be done with a simple tool.
[0040]
The fan of claim 6 includes a fan motor that rotationally drives the fan, the fan motor rotating shaft being inserted into the boss of the fan, and the fan holding structure according to any one of claims 1 to 5. As a result, the fan and fan motor rotating shaft can be held stably, a stable boundary condition between the fan and fan motor rotating shaft can be obtained, and the fan's eigenvalue can be stabilized. Can be provided.
[0041]
According to a seventh aspect of the present invention, there is provided a blower that sets a rotation speed that avoids resonance between vibration transmitted through the rotation axis of the fan motor and the eigenvalue of the fan, or vibration generated by cogging of the fan motor and resonance of the fan. Since the number setting means is provided, resonance can be avoided by setting the rotational speed, and a low noise blower can be provided.
[0042]
In addition, since the blower of claim 8 is controlled to the rotational speed set by the rotational speed setting means using feedback control, the blower is controlled to the set target rotational speed for avoiding resonance. It is easy to provide a low noise blower by controlling the number of revolutions so as to avoid the resonance.
[0043]
Moreover, since the refrigerator-freezer of Claim 9 mounts the air blower in any one of Claims 6 thru | or 8, the low-noise refrigerator-freezer can be provided.
[0044]
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a fan according to a first embodiment.
FIG. 2 is a diagram illustrating a holding structure between a fan and a fan motor rotating shaft according to the first embodiment.
3 is a cross-sectional view of a main part showing a holding portion between the fan boss of FIG. 2 and the rotation shaft of the fan motor.
FIG. 4 is a simplified view of the refrigerator-freezer of Embodiment 2 as viewed from the front.
FIG. 5 is a simplified view of the refrigerator-freezer of Embodiment 2 as viewed from the rear.
FIG. 6 is a view showing a conventional fan.
FIG. 7 is a view showing a conventional structure for holding a fan and a fan motor rotating shaft.
8 is a cross-sectional view of a main part showing a holding portion between the fan boss and the rotation shaft of the fan motor in FIG. 7;
FIG. 9 is a block diagram showing feedback control.
FIG. 10 is a cross-sectional view of a main part showing another conventional fan holding structure.
[Explanation of symbols]
1 fan, 2 boss, 3 axis, 4 axis, 5 fan motor, 6 rotation axis, 7 spring, 8 spring, 1a, 1b blower, 11 refrigerator-freezer, 12 cooler, 18 compressor, 19 microcomputer.

Claims (9)

A boss that supports the fan blades, and a boss shaft portion that is integrally fixed to the boss and is fitted to the rotation shaft and transmits the rotation of the rotation shaft to the blades, in the boss shaft direction of the fan and in the centrifugal direction of the boss shaft A fan holding structure comprising a plurality of holding means for tightening and restricting the movement of the fan. 2. The boss shaft portion includes an inner portion housed inside the boss and an outer portion exposed to the outside of the boss, and has holding means on the inner side and the outer side of the boss shaft. The holding structure of the described fan. 2. The fan holding structure according to claim 1, wherein the holding means is a spring. 4. The fan holding structure according to claim 3, wherein the holding means has a slit. The fan holding structure according to claim 1, wherein the holding means is a screw. 6. A blower comprising a fan motor for rotationally driving a fan, the rotating shaft of the fan motor being inserted into a boss of the fan, and the fan holding structure according to claim 1 being held. . Rotational speed setting means is provided for setting the rotational speed to avoid the resonance between the vibration transmitted through the rotation axis of the fan motor and the eigenvalue of the fan, or the vibration generated by cogging of the fan motor and the eigenvalue of the fan. The blower according to claim 6. The blower according to claim 7, wherein the rotational speed set by the rotational speed setting means is controlled using feedback control. 9. A refrigerator-freezer having a function of blowing cold air cooled by a cooler into a refrigerator-freezer or a function of blowing air to a compressor outer portion in order to suppress an increase in temperature of the compressor. A refrigerator-freezer comprising the blower according to claim 1 mounted thereon.

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