JPH04200502A - Drier - Google Patents

Abstract

PURPOSE:To widely lower the noise level by installing a tapered inside case having holes in the inside of a case. CONSTITUTION:A tapered inside case 1 having the maximum outside diameter being smaller than the inside diameter of the inside of a case 2 is provided in the outside periphery of a motor 5, a fan 4 and a heater 5. In this inside case 1, many holes 6 are formed in the cylindrical direction and the peripheral direction, and also, a back air layer 7 whose thickness is varied in the longitudinal direction is formed between the outside peripheral surface and the case 2. A resonance frequency (f) in which the diameter of the hole 6, thickness of the inside case 1, a pitch of the hole 6, and thickness of the back air layer 7 are denoted as psi, (t), D, and L, respectively, is expressed by an expression. For instance, when the inside case 1 which becomes L=1mm, and L=3mm in a suction port 50, and a blowout port 51, respectively, and becomes 2mm in an average is installed, a frequency within a range of 830-1430KHz centering around 1KHz can be subjected to sound absorption, and a noise level of the whole can be lowered effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a dryer used for drying hair, etc., and is of a type that sends air in the axial direction of a fan.

[Conventional technology]

In recent years, due to the desire to make life more comfortable and the diversification of living hours,
Demand for quieter home appliances is increasing.

Traditionally, sound has been taken by installing temporary holes in home appliances, etc., and using the air layer formed by the outside wall to absorb sound. However, in this case, the sound absorption effect is only in a narrow range of resonant frequencies determined by the diameter of the hole, the thickness of the plate, the pinch of the hole, and the thickness of the air tank.

Furthermore, since conventional hair dryers have a cylindrical shape, when frequency analysis of noise is performed, peaks appear at and around frequencies that are thought to be caused by air column resonance, as shown in Figure 3. Therefore, by absorbing sound at frequencies around this peak frequency, it is possible to effectively make the dryer quiet. The purpose is to provide a dryer for drying hair that is silent by effectively absorbing generated noise in a specific frequency range.

[Means for Solving the Problems] The dryer of the present invention includes a motor and a fan that is coaxially attached to the rotating shaft of the motor to send air in the axial direction, and a heater that gives heat to the air. In this dryer, the dryer is installed inside a cylindrical case with an air outlet at the other end. It is characterized by the formation of a back air layer with varying thickness in the longitudinal direction between the installed case and the inner case, and the double structure of the case and inner case absorbs sound in a specific frequency range to reduce noise. It is something that

[For production]

The dryer according to the present invention has a tapered perforated inner case installed inside the case, thereby producing noise at a resonant frequency determined by the thickness of the back air layer, hole diameter, hole pitch, etc., which varies widely in the cylindrical direction. It is possible to reduce the level over a wide range.

C Embodiment] The present invention will be described below in detail based on an embodiment shown in FIGS. 1 and 2.

Reference numeral 2 denotes a plastic case having a substantially cylindrical shape, and has a suction port 50 opened at one end and an outlet 51 opened at the other end. Further, inside the case 2, a motor 3 and a fan 4 for blowing air, and a heater 5 for applying heat to the air are arranged.

A tapered inner case 1 having a maximum outer diameter smaller than the inner diameter of the case 2 is disposed around the outer periphery of a motor 3, a fan 4, and a heater 5. This inner case 1 has a large number of holes 6 formed in the cylindrical and circumferential directions, and also forms a rear air layer 7 whose thickness changes in the longitudinal direction between the outer peripheral surface and the inner surface of the case 2.

Now, as shown in Fig. 2, if the diameter of the hole 6 is ψ, the thickness of the inner case 1 is also D, the pinch of the hole 6 is D, and the thickness of the rear air layer 7 is L, the resonance frequency f is C; the speed of sound is It is expressed as follows, and the noise of this resonance frequency f can be absorbed.

In the case of a dryer with a frequency characteristic having a peak around I KHz as shown in Fig. 3, for example, the φ-1 arrangement D-2
By setting L = 2 torso t, = 2 torso, I
Although it is possible to absorb sound at the peak frequency of KHz, in order to further absorb sound broadly around I KHz, as in the inner case 1 shown in FIG. = 3 cabinets, and by installing the inner case 1 so that the average number is 2, I KHz
It is now possible to absorb sound in the frequency range of 830 to 1430 K) Iz, effectively reducing the overall noise level.

〔Effect of the invention〕

According to the present invention, it is possible to absorb sound over a wide frequency range, and as a result, the noise of the dryer can be effectively reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of the present invention.
FIG. 3, which is an enlarged view of the main part of the same as above, is a graph showing the result of frequency analysis of the noise of a conventional dryer. ■...Inner case, 50...Suction port, 51...
・Air outlet, 2... Case, 3... Motor, 4.
... Fan, 5... Heater, 6... Hole, 7... Back air layer.

Claims (1)

[Claims] (1) A motor and a fan coaxially attached to the rotating shaft to send air in the axial direction, and a heater that gives heat to the air.
In a dryer that is installed inside a cylindrical case with an inlet at one end and an outlet at the other end, there is a tube with multiple holes inside the case whose outer diameter increases in a tapered manner from one end to the other. A dryer with a shaped inner case and a back air layer with uneven thickness in the longitudinal direction between the cases.