JPS63238807A - Low noise hair dryer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a low-noise hair dryer that reduces noise such as motor rotation noise and fan wind noise.

[Background Art] Generally, a hair dryer, as shown in FIG. The intake port 6 is provided at one place in the housing 1, and includes a rectifying plate 4 that rectifies the flow, a heater 5 that is a heat source, etc.
The air introduced into the housing 1 by the rotation of the 7-ton 3 is heated by a heater 5 and then discharged as hot air from a discharge lower provided elsewhere in the housing 1. Hair dryers are required to be small, lightweight, and have a certain amount of airflow as their basic performance.In order to meet these demands, it has been considered to increase the number of rotations of the 77-in-3 to increase the amount of airflow. It will be done. However, 7
A problem arises in that the noise increases as the rotational speed of the 7/3 increases. In order to avoid such problems, efforts have been made to ensure a specified air volume at low rotational speeds by improving the characteristics of the motor 2 and the shape of the 7-ring 3, but it is difficult to obtain a satisfactory result. Not yet reached.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to reduce noise without reducing air volume by arranging a silencing element in at least a portion of the housing. An object of the present invention is to provide a low-noise hair dryer that reduces the generation of.

[Disclosure 1 (Structure) The low-noise hair dryer according to the present invention includes: an inner tube made of a viscoelastic material; and a rigid outer tube surrounding the inner tube with a space between the outer periphery of the inner tube. The sound-muffling element is a double pipe made up of This reduces the noise caused by

(Basic Principle) The basic principle of the silencing element 10 used in the present invention will be explained below. As shown in FIG. 5, the silencing element 10 is a double pipe in which an inner pipe 11 made of a viscoelastic material and an outer pipe 12 made of a rigid body are disposed with a space 13 interposed therebetween. The outer tube 11 is made of a thin wall made of rubber or the like so as to be easily vibrated by sound waves passing through the inside, and the outer tube 12 is made of a thick wall made of metal, synthetic resin, etc. so as not to be easily vibrated by sound waves of normal sound pressure. ing. Further, at both ends of the muffling element 10 in the axial direction, a portion corresponding to the space 13 between the inner cylinder 11 and the outer cylinder 12 is closed by a side plate 15, so that the space 13 has a sealed structure. There is. When a sound wave passes through the inner tube 11 of the silencing element 10 configured in this way, as shown in FIG. vibration occurs. When the inner tube 11 is cylindrical, the resonant frequency fr is expressed by the following formula, where E is the Young's modulus of the inner tube wall material, ρW is the density of the inner tube wall material, and r is the inner tube wall material density. The radius of the inner peripheral surface, ρa is the density of air, C is the speed of sound in air, t is the wall thickness of the inner tube, and d is the average thickness of the space formed between the inner tube and the outer tube. .

As described above, when a sound wave near the resonance frequency of the silencing element 10 passes through the inner tube 11, the inner tube 11 vibrates. Therefore, if a viscoelastic material such as rubber is used as the material for forming the inner tube 11, and the wall is made thin enough to easily vibrate due to sound pressure, the energy of the sound waves can be transferred to the inner tube 11.
It is consumed as a hysteresis loss of 1, and the passing sound wave is attenuated. Moreover, since the outer periphery of the inner tube 11 is covered with the outer tube 12, the sound waves do not go around to the outside of the inner tube 11 and impede the vibration caused by the sound waves passing inside the inner tube 11.

Generally, the main noise sources in hair dryers are motors 2 and 7.
According to the knowledge that the noise generated from the noise source mainly leaks from the suction port 6 and the discharge lower, the noise can be reduced by arranging the silencing element 10 in the noise transmission path in the housing 1. The present invention has been made based on the above.

(Embodiment 1) As shown in FIG. 1, the housing 1 is formed into a straight tube shape, and an inlet 6 is provided at one end in the axial direction of the housing 1.
opens. Further, a 7-ring 3 is disposed near the suction port 6. The above-mentioned silencing element 10 has the intake ports 6 to 7.
The part leading to Anne 3) forms S-Using 1. That is, (g) the outer shell of the housing 1 serves as the outer tube 12, and the inner tube 11 is disposed inside the outer tube 12 via the space 13.

With this configuration, a part of the housing 1 is formed by the sound deadening element 10, and the wind noise of the 7-ring 3 leaking from the suction port 6 is reduced, so that noise is reduced.

Of course, the resonance frequency of the silencing element 10 is set to correspond to the highest frequency component of the sound pressure level contained in the target noise source. In addition, since the silencing element 10 is cylindrical, air can freely pass through the inside without obstructing the air circulation.
It's number 1.

(Embodiment 2) As shown in FIG. 2, in this embodiment, hot air heated by the heater 5 is discharged from a region between the 7T cylinder 3 which is rotationally driven by the motor 2 and the suction port 6. A silencing element 10 is disposed at each location near the discharge lower. That is, by disposing the silencing elements 10 at the suction port 6 and the discharge lower portion formed at both ends of the housing 1, the noise reduction element 10 is provided at each of the suction port 6 and the discharge lower portion formed at both ends of the housing 1.
The noise generated in this embodiment does not leak to the outside through the suction port 6 or the discharge lower, and the noise is further reduced compared to the first embodiment.

In the first and second embodiments, the silencing element 10 is disposed only in a part of the housing 1;
The sound deadening element 10 may be arranged over the entire length of the pipe.

(Embodiment 3) In this embodiment, as shown in FIG. 3, a bell mouth 8 is disposed near the suction port 6 and between the 7-ring 3. The bell mouth 8 is formed so that the cross-sectional area is the largest at one end on the suction port 6 side, and the wIr'rTJ product is smallest at the one end on the 7-ang 3 side. That is, the inlet 6
In order to efficiently accelerate the introduced air by the 77n3, the air is collected in the portion of the 77n3 where the acceleration performance is high. This bell mouth 8 has a sound deadening element 1
0, the noise on the suction port 6 side can be reduced similarly to the first embodiment.

(Example 4) In this example, as shown in tIS4 diagram, the silencing element 10
A so-called porous sound-absorbing material 14 such as glass wool, urethane, or felt is arranged in the space 13, and the sound-absorbing element 10 is inserted into the housing at a portion between the intake ports 6 and 7, as in the first embodiment. 1. The porous sound absorbing material 14 is arranged so as to be in contact with the inner tube 11. Therefore, the occurrence of undulation in the inner pipe 11 due to the high-speed airflow passing through the inner pipe 11 is prevented, and the generation of noise due to the undulation and the increase in flow resistance due to the undulation are prevented. .

[Effects of the Invention 1] As described above, the present invention provides a double tube comprising an inner tube made of a viscoelastic material and a rigid outer tube surrounding the inner tube with a space between the outer periphery of the inner tube. A pipe is used as a sound deadening element, and the sound deadening element is disposed in at least a part of the housing in which a motor, fan, heater, etc. are housed in a manner that allows air to circulate. This arrangement has the advantage that noise generated within the housing can be reduced. Moreover, the sound deadening element is a double pipe and does not obstruct the flow of air through the inner pipe, so even if the fan rotation speed is increased, no large noise will be generated.
This makes it possible to provide a hair dryer with low noise and large air volume. Furthermore, since the silencing element forms a part of the housing, the housing does not become large.

[Brief explanation of drawings]

Figure 1 is a partially cutaway perspective view showing Embodiment 1 of the present invention;
The figure is a cross-sectional view showing a second embodiment of the present invention, FIG. 3 is a cross-sectional view of main parts showing a third embodiment of the present invention, and FIGS. 5 is a partially cutaway perspective view of a sound deadening element used in the present invention, FIG. 6 is an explanatory diagram of the same operation as above, and FIG. 7 is a general view of the hair dryer according to the present invention. FIG. 1 is a housing, 2 is a motor, 3 is a 7-ring, 5 is a heater, 6 is an inlet, 7 is a discharge port, 8 is a bell mouth, 10 is a silencing element, 11 is an inner pipe, 12 is an outer pipe, 13 is a space Part, 14
is a porous sound absorbing material. Agent Patent Attorney Ishi 1) Ai Figure 7, Figure 4 (b) Figure 5

Claims (3)

[Claims] (1) A double pipe consisting of an inner pipe made of a viscoelastic material and a rigid outer pipe surrounding the inner pipe with a space between the outer periphery of the inner pipe is used as a sound deadening element, and a motor, a fan, A low-noise hair dryer characterized in that a silencing element is disposed in at least a part of a housing in which a heater etc. are installed in a manner that allows air to circulate. (2) Claim 1 characterized in that a porous sound-absorbing material such as glass wool, urethane, or felt is disposed in the space between the inner tube and the outer tube so as to be in contact with the inner tube. Low noise hair dryer as described. (3) Claims characterized in that the above-mentioned silencing element is disposed in a part of a bell mouth that is disposed on a flow path from an inlet formed in one part of the housing to a fan and narrows down the airflow. The low-noise hair dryer according to item 1.