CN103358856A - Sound-absorption dust shield for passenger vehicle scavenge port - Google Patents

Abstract

The invention discloses a sound-absorption dust shield for a passenger vehicle scavenge port, which is characterized in that the sound-absorption dust shield, against which the scavenge port of the vehicle body is propped, adopts a trapezoid structure; the upper surface of the sound-absorption dust shield is a micropunch board. Through adopting the structure, the sound-absorption dust shield can complement the insufficient sound-absorption effect of the scavenge port, and reduce dust which enters the passenger cabin; the sound-absorption dust shield is arranged between the in-vehicle sheet metal and the decorative inner-shield; the cost increase of a single vehicle is low, and the technology and the assembly are simple.

Description

A kind of sound absorption dust hood of manned vehicle scavenge port

Technical field

The present invention relates to auto body and make field, particularly a kind of sound absorption dust hood of manned vehicle scavenge port.

Background technology

General manned vehicle all has crew module and the extraneous scavenge port that communicates at the body in white afterbody, is used for keeping the pressure balance of the interior air of car and ambient atmosphere.For example close door moment interior pressure changes, and does not exchange to alleviate interior pressure and suddenly increases if having scavenge port and the external world to carry out gas, and pressure will cause the constriction of people's ear drum membrane.

Scavenge port position on body in white is understood the grid of additional plastic material usually at present, and rubber diaphragm is housed between the grid.Rubber diaphragm sector-meeting and grid are out of shape in taping process under this structure, cause diaphragm to rise prominent, and perhaps elastomeric material itself is because the impact such as temperature causes self-deformation, thereby do not fit with grid, so all can cause the sound insulation effect inefficacy of scavenge port; Perhaps the sound reduction index of rubber itself is lower than the sound reduction index of metallic iron, so scavenge port position rubber substituted metal, defening effect is relatively poor, especially be positioned at the scavenge port of trail pipe side, exhaust roar can be easy to pass in the car, causes the passenger to complain, simultaneously scavenge port is usually located near the wheel cover outside car or near rear the guarantor, the sandy soil that Vehicle Driving Cycle is rolled can by scavenge port along with air into the car, converge and to amass near scavenge port, between vehicle body sheet metal and the Che Nei decorative cover plate.

For above-mentioned problem, a kind of novel sound absorption dust hood is provided, preventing that effectively at utmost absorbing noise under the dust prerequisite into the car is the problem that prior art need to solve.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of sound absorption dust hood of manned vehicle scavenge port, to reach in the purpose that effectively prevents from utmost absorbing under the dust prerequisite into the car noise.

For achieving the above object, technical scheme of the present invention is that a kind of sound absorption dust hood of manned vehicle scavenge port is characterized in that: described sound absorption dust hood is the scavenge port that trapezium structure withstands vehicle body; The upper surface panel of sound absorption dust hood is microperforated panel, thereby realizes the sound absorption dust-separation to car body.

The lower surface of described sound absorption dust hood and the horizontal surface of scavenge port are certain angle of inclination downwards, thereby make things convenient for silt to discharge.

Described sound absorption dust hood and scavenge port grid use same material.

Described sound absorption dust hood adopts the connection mode cover of box like and lid to be buckled on the scavenge port.

A kind of sound absorption dust hood of manned vehicle scavenge port, owing to adopting above-mentioned structure, the present invention can remedy the deficiency of the defening effect of scavenge port own, reduce simultaneously sand and dust and enter the crew module, be deposited between the interior panel beating of vehicle body and the decoration inner casing, and the cost that bicycle increases is lower, and technique and assembling are simple.

Description of drawings

The present invention is further detailed explanation below in conjunction with the drawings and specific embodiments;

Fig. 1 is the sound absorption dust hood structural representation of a kind of manned vehicle scavenge port of the present invention;

Fig. 2 is sound absorption dust hood coefficient of sound-absorption and the oscillation frequency diagram of curves of a kind of manned vehicle scavenge port of the present invention;

Fig. 3 is existing dust hood structural representation;

In Fig. 1,1, upper surface; 2, lower surface; 3, grid; 4, diaphragm.

The specific embodiment

As shown in Figure 3; scavenge port position on body in white is understood the grid 3 of additional plastic material usually at present; rubber diaphragm 4 is housed between the grid 3; diaphragm 4 upper limbs and grid 3 are bonding; its excess-three limit relies on the diaphragm deadweight to be fitted in grid 3 housings, and diaphragm 4 is positioned at outside the car, so be equivalent to check valve; the car internal gas pressure is excessive will wash diaphragm, hold-off pressure open.This structure is easily because diaphragm 4 breaks away from or change is gone and cause the sound insulation effect to lose efficacy.And the present invention can remedy the deficiency of the defening effect of scavenge port own, reduces simultaneously sand and dust and enters the crew module, be deposited between the interior panel beating of vehicle body and the decoration inner casing, and the cost that bicycle increases is lower, and technique and assembling are simply.

Specifically, as shown in Figure 1, the scavenge port position increases the sound absorption dust hood in the crew module, utilizes left, center, right, lower surface sealing, and upper surface 1 reduces noise transfer for the box-like sound absorption dust hood of micropunch and the minimizing sandy soil enter.

Wherein sound absorption is played in upper surface 1 micropunch, all the other play the sandy soil effect that intercepts on four sides, the gravity that lower surface 2 angles of inclination need to guarantee to pile up dust along the component of lower surface direction greater than sandy soil and lower surface viscous resistance, angle skids off outside the scavenge port thereby make under the sandy soil, so need to be tried one's best greatly.The micropunch aperture of upper surface 1 can not be excessive, otherwise affect acoustically effective, and hole count can not be very few, otherwise affect the ventilation function of scavenge port itself, but quantity too much also can affect acoustically effective, so need comprehensive Design.

Whole sound absorption dust hood uses and scavenge port grid same material, adopts the connection mode cover of box like and lid to be buckled on the scavenge port.And scavenge port is nearer apart from rear taillight, usually has enough space mounting sound absorption dust hoods.

For example, the design parameters of supposing certain car is upper surface aperture 2mm, sound absorption dust hood wall thickness 1.5mm, 45 micropunch of upper surface design at 130mm * 50mm, utilize whole crew module as the back cavity of perforated plate, the length of back cavity is that the size of crew module's Width is about 1m, and the normal temperature air acoustic speed of propagation is 340m/s, density of air is 1.2kg/m3, and the coefficient of viscosity is 0.0000185kg/ms.The coefficient of sound-absorption formula is

$a_n=\frac{4r}{{(1+r)}^2+{[\mathrm{wm}-\cot \left(\frac{\mathrm{wD}}{c_0}\right)]}^2}$

Wherein:

$r=\frac{32\mathrm{\ηt}}{\mathrm{\σ}{\mathrm{\ρ}}_0{c}_0{d}^2}{k}_r$ ， $k_r=\sqrt{1+\frac{k^2}{32}}+\frac{\sqrt{2}\mathrm{kd}}{32t}$ ， $\mathrm{wm}=\frac{{\mathrm{wtk}}_m}{{\mathrm{\σc}}_0}$ ，

$k_m=1+{(3^2+\frac{k^2}{2})}^{-\frac{1}{2}}+0.85\frac{d}{t}$ ， $k=d\sqrt{\frac{{\mathrm{w\ρ}}_0}{4\mathrm{\η}}}$

a _nBe coefficient of sound-absorption, absorb the ratio of acoustic energy and incident acoustic energy, 0 representative does not absorb sound fully, fully sound absorption of 1 representative;

D is aperture 2mm;

T is microperforated panel thickness 1.5mm;

Be the upper surface percentage of perforation, i.e. the ratio of the gross area in hole and the perforated plate gross area, this routine result of calculation is

, wherein 45 is upper surface micropunch quantity, 130 * 50 (mm ²) be the upper surface gross area;

D is rear cavity length 1m;

c ₀Be velocity of sound 340m/s;

ρ ₀For density of air is 1.2kg/m3;

η is coefficient of viscosity 0.0000185kg/ms

W is angular frequency, with the pass of frequency be w=2 π f, f is the incident acoustic wave frequency

All the other k, k _r, k _m, r is process variable, utilizes coefficient of sound-absorption that above-mentioned parameter obtains with the curve of frequency change as shown in Figure 2.

Air can form standing wave in side direction in the 1100Hz-1200Hz tire, resonates, and this resonance may be coupled with other vibration and acoustics, becomes one of important noise source; The pump gas noise band on tire and road surface is wider, and the speed of a motor vehicle 60km/h respective pump gas noise frequency commonly used of car is 800Hz-1200Hz; Exhaust roar is the lower airborne noise of frequency normally, if the frictional noise of air-flow shakiness tail pipe when middle high rotating speed is just apparent in view.The acoustically effective of this sound absorption dust hood increases with the increase of frequency, can reach 0.35-0.42 at 800Hz-1200Hz, plays acoustically effective.By the adjusting to sound absorption dust hood physical parameter, make the crest frequency of sound absorption corresponding with the frequency of the problem of generation, reach maximum acoustically effective.

The above has carried out exemplary description to the present invention by reference to the accompanying drawings; obviously specific implementation of the present invention is not subjected to the restriction of aforesaid way; as long as the various improvement of having adopted technical solution of the present invention to carry out, or directly apply to other occasion without improvement, all within protection scope of the present invention.

Claims (5)

1. the sound absorption dust hood of a manned vehicle scavenge port, it is characterized in that: described sound absorption dust hood is the scavenge port that trapezium structure withstands vehicle body; Upper surface (1) plate of sound absorption dust hood is microperforated panel.

2. the sound absorption dust hood of a kind of manned vehicle scavenge port according to claim 1 is characterized in that: the horizontal surface of the lower surface of described sound absorption dust hood (2) and scavenge port is certain angle of inclination downwards.

3. the sound absorption dust hood of a kind of manned vehicle scavenge port according to claim 1 is characterized in that: described sound absorption dust hood and scavenge port grid use same material.

4. the sound absorption dust hood of a kind of manned vehicle scavenge port according to claim 1 is characterized in that: described sound absorption dust hood adopts the connection mode cover of box like and lid to be buckled on the scavenge port.

5. the sound absorption dust hood of a kind of manned vehicle scavenge port according to claim 1, it is characterized in that: the upper surface of described sound absorption dust hood (1) percentage of perforation is 0.2, namely

, wherein n is upper surface micropunch quantity, s is the upper surface gross area.

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