JP2573211B2 - Low noise hair dryer - Google Patents

Description

Description: 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, as shown in FIG. 7, a hair dryer rectifies a motor 2 as a driving source, a fan 3 rotated by the motor 2, and an air flow accelerated by the fan 3 in a hollow housing 1. The air introduced into the housing 1 by the rotation of the fan 3 from a suction port 6 provided at one place of the housing 1 is heated by the heater 5. Later, the hot air is discharged from a discharge port 7 provided in another part of the housing 1. The hair dryer is required to have a small size, light weight, and an element of securing a predetermined air volume as basic performance, and it is conceivable to increase the rotation speed of the fan 3 to increase the air volume in order to satisfy such a requirement. . However,
There is a problem that noise increases as the rotation speed of the fan 3 increases. In order to avoid such a problem, efforts have been made to improve the characteristics of the motor 2 and the shape of the fan 3 to secure a predetermined airflow at a low rotation speed, but have achieved satisfactory results. Not in.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to dispose a noise reduction element in at least a part of a housing so as to reduce noise without reducing air volume. An object of the present invention is to provide a low-noise hair dryer with reduced generation of hair.

[Disclosure of the Invention] (Configuration) A low-noise hair dryer according to the present invention includes a housing in which a motor, a fan, a heater, and the like are housed, and heats air introduced from a suction port provided in the housing to a discharge port. A hairdryer to be discharged from the inner pipe made of a viscoelastic material, and a double pipe consisting of a rigid outer pipe surrounding the inner pipe via a space between the inner pipe and the outer circumference of the inner pipe as a sound deadening element. The sound deadening element is disposed on the flow path between the suction port and the discharge port in the housing so that the inside of the inner pipe is used as a ventilation path. This configuration reduces noise generated in the housing. It is to let.

(Basic Principle) The basic principle of the muffling element 10 used in the present invention will be described below. As shown in FIG. 5, the silencing element 10 includes an inner tube 11 made of a viscoelastic material and an outer tube 12
The inner tube 11 is 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 easily formed by sound waves of normal sound pressure. It is formed thick with metal or synthetic resin so as not to vibrate. At both ends in the axial direction of the silencing element 10, a portion corresponding to the space 13 between the inner tube 11 and the outer tube 12 is closed by the side plate 15, and the space 13 is sealed. I have. When a sound wave passes through the inner tube 11 of the silencing element 10 configured as described above, as shown in FIG. 6, each part of the inner tube 11 has a radial direction excited by a sound wave near the resonance frequency of the silencing element 10. Vibration occurs. When the inner tube 11 is a cylinder, the resonance frequency fr can be expressed by the following equation.

Here, E is the Young's modulus of the wall material of the inner tube, ρw is the density of the wall material of the inner tube, r is the radius of the inner peripheral surface of the inner tube, ρa is the density of air, c is the speed of sound in air, t is the thickness of the inner pipe, and d is the average value of the thickness of the space formed between the inner pipe and the outer pipe.

As described above, when a sound wave near the resonance frequency of the silencing element 10 passes through the inner tube 11, the vibration of the inner tube 11 occurs. 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 by sound pressure, the energy of the sound wave is consumed as hysteresis loss of the inner tube 11 and the passing sound wave Will attenuate. Moreover, since the outer periphery of the inner tube 11 is covered with the outer tube 12, the sound wave does not wrap around the inner tube 11 and hinder the vibration caused by the sound wave passing inside the inner tube 11.

Generally, the main noise sources in the hair dryer are the motor 2 and the fan 3, and the noise generated from the noise source mainly leaks from the suction port 6 and the discharge port 7. Therefore, the noise reduction element 10 is provided in the noise transmission path in the housing 1. Accordingly, the present invention has been made based on the finding that noise is reduced.

(Embodiment 1) As shown in Fig. 1, the housing 1 is formed in a straight tubular shape, and an inlet 6 is provided at one end of the housing 1 in the axial direction.
Opens. Further, a fan 3 is provided near the suction port 6. The above-described silencing element 10 forms the housing 1 at a portion from the suction port 6 to the fan 3. That is,
The outer shell of the housing 1 becomes the outer tube 12, and a space
The inner pipe 11 is disposed via the air passage 13 so that the inside is an air passage. With this configuration, a part of the housing 1 is formed by the sound deadening element 10, so that the wind noise and the like of the fan 3 leaking from the inlet 6 are reduced, so that the noise is reduced. Here, it goes without saying that the resonance frequency of the silencing element 10 is set so as to correspond to the highest frequency component of the sound pressure level included in the target noise source. Further, since the silencing element 10 has a cylindrical shape, the air freely passes through the inside, and does not hinder the flow of the air. Moreover, since the silencing element 10 forms a part of the outer shell of the housing 1, the housing 1 does not increase in size.

(Embodiment 2) In this embodiment, as shown in FIG. 2, a portion between a fan 3 driven by a motor 2 and a suction port 6 and a discharge port from which hot air heated by a heater 5 is discharged. A silencing element 10 is provided in each of the portions near 7. That is, the noise generated by the motor 2 and the fan 3 disposed in the housing 1 is reduced by disposing the silencing elements 10 at the suction port 6 and the discharge port 7 formed at both ends of the housing 1. There is no leakage to the outside through the suction port 6 and the discharge port 7, and the noise is further reduced as compared with the first embodiment.

In the first and second embodiments, the muffling element 10 is provided only in a part of the housing 1.
May be provided over the entire length of the muffler.

(Embodiment 3) In the present embodiment, as shown in FIG. 3, a bell mouth 8 is disposed between the fan 3 and the suction port 6, and a silencing element 10 is disposed on the bell mouth 8. Have been. The bell mouth 8 is formed so as to have the largest sectional area at one end on the suction port 6 side and the smallest sectional area at one end on the fan 3 side. That is, it acts to collect air in a portion of the fan 3 having high acceleration performance so that the air introduced from the suction port 6 is efficiently accelerated by the fan 3. By disposing the muffling element 10 in the bell mouth 8, the noise on the suction port 6 side can be reduced as in the first embodiment.

Fourth Embodiment In this embodiment, as shown in FIG. 4, a so-called porous sound absorbing material 14 such as glass wool, urethane, or felt is provided in a space 13 of a sound deadening element 10.
Is disposed in the housing 1 at a position between the suction port 6 and the fan 3 as in the first embodiment. The porous sound absorbing material 14 is provided so as to contact the inner tube 11. Therefore, the inner tube
The swelling of the inner tube 11 due to the high-speed airflow passing through the inside 11 is prevented, so that noise due to the swelling and increase in flow resistance due to the swelling are prevented.

[Effects of the Invention] As described above, the present invention includes a housing in which a motor, a fan, a heater, and the like are housed, and heats air introduced from a suction port provided in the housing and discharges the hair dryer from a discharge port. A double pipe consisting of an inner pipe made of a material having viscoelasticity and a rigid outer pipe surrounding the inner pipe via a space between the inner pipe and the outer periphery of the inner pipe is used as a sound deadening element. The muffling element is arranged on the flow path between the suction port and the discharge port so that the inside of the inner tube is used as an air passage, and the muffling element is arranged on the flow path provided in the housing. This has an advantage that noise generated in the housing can be reduced. Moreover, since the silencing element is a double pipe and does not impede the flow of air through the inner pipe, no noise is generated even when the rotation speed of the fan is increased, so that a hair dryer with low noise and a large air volume can be provided. There is.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing Embodiment 1 of the present invention, and FIG.
FIG. 3 is a sectional view showing a second embodiment of the present invention, FIG. 3 is a sectional view of a main part showing a third embodiment of the present invention, and FIGS. 4 (a) and 4 (b) each show a fourth embodiment of the present invention. FIG. 5 is a partially cutaway perspective view of a sound deadening element used in the present invention, FIG. 6 is an operation explanatory view of the same, and FIG. 7 is a general view of a hair dryer according to the present invention. FIG. 2 is a cross-sectional view showing a typical configuration. 1 is a housing, 2 is a motor, 3 is a fan, 5 is a heater, 6 is a suction port, 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, and 13 is a space. , 14 are porous sound absorbing materials.

Continuation of the front page (56) References JP-A-62-294799 (JP, A) JP-A 54-65277 (JP, U) JP-A 50-98967 (JP, U) JP-A 59-111605 (JP) , U) Japanese Utility Model Showa 61-14121 (JP, U) JP-B 55-46486 (JP, B2)

Claims (3)

(57) [Claims] 1. A hair dryer which has a housing in which a motor, a fan, a heater and the like are housed, and which heats air introduced from a suction port provided in the housing and discharges the air from a discharge port, and has viscoelasticity. A double pipe consisting of an inner pipe made of a material and a rigid outer pipe surrounding the inner pipe through a space between the outer circumference of the inner pipe is used as a sound deadening element, and is provided between the suction port and the discharge port in the housing. A low-noise hair dryer, wherein the silencing element is disposed on the flow path such that the inside of the inner tube is used as an air passage. 2. A structure according to claim 1, wherein a porous sound absorbing material such as glass wool, urethane, felt or the like is disposed in a space between the inner tube and the outer tube so as to contact the inner tube. The low-noise hair dryer according to the item. 3. A patent wherein the muffling element is provided in a part of a bell mouth which is provided on a flow passage from a suction port formed in one part of a housing to a fan and narrows an air flow. The low-noise hair dryer according to claim 1.