机械工程概论英语语论文.doc

机械工程概论双语课 题： 助听器 姓 名： 谭伟学 号： 20127733指 导 教 师： 李怀仙完 成 日 期： 2012年12月27日成 绩： AbstractIts easy to take sound for granted, but when you lose it ,due to a serious hearing disorder。How do you do ?thankfully this tiny hearing aid bring back the music Loose of hearing causes a serious handicap, but happily It can be remedied thanks to hearing aid. A hearing aid is an electric device which typically fits in or behind the wearers ear, and is designed to amplify and modulate sound for the wearer. Earlier devices, known as ear trumpets or ear horns,Similar devices include the bone anchored hearing aid, and cochlear implant.图 1 Invisible hearing aid1. Introduce about hearing AidHearing Aid is a help to Hearing crippled improve Hearing impairment, and further increase the session with others of the communication ability of tools, equipment, equipment and instrument, etc. Hearing AIDS have the power and the power of the two kinds, the latter at present has been abandoned. The former and tube type and transistor type two kinds. Transistor type hearing aid the most clever light, appeared in 1950 after replace valve type and is widely used. In a broad sense that can effectively put the sound to the ear various device can see as hearing AIDS, a narrow sense about hearing aid is a electroacoustic amplifier, through it will put the deaf hear voice ambassador to the original can not hear clearly, cant hear voice, this device is hearing aid. 2. Hearing aid development historyIn 1878, the United States scientists Bell invented the first carbon type hearing aid. The hearing aid is by carbon microphone, headphones, battery, wire etc have been assembled.In 1890, Austrian scientist Ferdinant Alt preparation out of the first generation tube hearing aid.In 1920, thermionic valve (hot cathode tube) was soon, appear vacuum tube hearing aid. With the developing of the technology of vacuum tubes, hearing aid volume gradually become smaller, realize the host and the separation of the battery.In 1943, began to develop integrated type hearing aid, the power supply, microphone and amplifier installed in a small box, hearing AIDS in the volume of more and more small, finally, race like cigarette case, carry has very convenient.In 1948, semiconductor, electronic engineers came immediately semiconductor technology applied in hearing AIDS, and obtain good results. The part of the semiconductor device, can make the volume of hearing AIDS further narrowed.In 1956, made a bte hearing aid, not only further reduced volume, advantages more than the glasses type and cassette hearing aid.In 1957, the ear type hearing aid was published, the emergence of tantalum capacitor, capacitance volume further reduced, transistor circuit to integrated circuit the miniaturization orientation rapid development. Along with large scale integrated circuit, the emergence of the volume of hearing AIDS further reduced, the ear type hearing aid after appearing soon, half ear a cavity, ear canal type, complete the ear canal type hearing aid arise, to a great extent, satisfy the patients psychological and beautiful on needs.1982 electret microphone to realize the advent of hearing AIDS miniaturization, sensitivity and resolution was to reach a new level.In 1990, the computer programming hearing aid appeared.In 1997, the digital hearing aid gain intelligent adjustment, use very convenient, performance reached higher level.So after a long time of development hearing aid technology has very mature.3. Type of Hearing aid 3.1The cassette hearing AIDS This are cheaper, but shape is too big, difficult to use, and the function of shortcomings, such as less.图 2 cassette hearing AIDS3.2 Bte hearing AIDS:It like banana curvature, fell in the ear, the average length of about 4 5 cm. Receiver open with a rigid plastic pipe made of guide sound hook connection and hung it on the auricle flange root, which hook the soft plastic pipe and ear die ear plugs into the ear a cavity and the ear canal. Because of good performance, the cabinet can be made into all kinds of color of skin, fell in the ear for the hair after the concealed, often not to outsiders, it is found that can meet the deaf psychological requirements图3 bte hearing AIDS3.3 Constant systems hearing AIDS: its main advantages are: appearance compact, easy to conceal, According to the ear canal shape customization, wearing comfortable, not off; Not easy go into water, the sweat, for the hearing aid maintenance.图4 Constant systems hearing AIDS4. Working principleFirst, the microphone receiving voice and put it into the wave form, turn energy into electrical energy. Second, Amplifier amplification signal. Third, headset (receiver) the signal into sound signal. Amplification of electrical signals into die to signal to the processed signals finally will sound output.图55. Invisible hearing aid manufacturing5.1 Ear impression processing5.1.1Check ear impressionReflect on whether there is a serious defect ear seal. Pass the ear of the seal should be bright and clean and the ears of a cavity and the ear canal shape, check the patient ear seal control and production of single is consistent. Ear canal without defect. The ear canal depth at least more than the second bending, CIC custom machine should be more than the depth of the first corner mouth 15 mm the second corner 3 4 mm if do ITE helix part should also be saturated.5.1.2 Ear seal cutting, grinding1 the pinna and tragus cutting: keep ear a cavity and helix part, 2 mm cut according to the size of the model to determine2 the ear canal cutting part: the hypothesis of the patients with hearing loss weight should be appropriately extended.3 grinding: In order to make the customized function smoothly into the ear canal4 use oily marker.5.2 The impression hangs waxMake wax evenly cover in the ear sample surface. More and more users hearing loss status differences 2 ITE method with the previous chapter hang5.3 Stamping production5.4 Casing manufacturing1 casing cutting: Movement size is also different, with grinding wheel will wear off the bottom shell surplus. But to leave enough space to internal movement. Leave enough positions as close as possible to the casing wear. Neat cutting types of custom machine as the panel with differences. Grinding also want to differentiate. As shown in figure 9-12 shows.2 casing burnish3 vent production :Make your wearing more comfortable, vent can reduce plugging ear effect4 installation crewmen casing5.5 Qanel (movement) removeHand turn punch drill out into the sound hole, fine holes and line hole.5.6 Grinding and polishing1 The cloth wheel polishing requirement: linking part and casing curve match, 2 after grinding. Want to have streamline selection, cannot have obvious joint board. To vent opening phase connection. Good vent is formed three ball drill in the panel corresponding casing on vent part of the drill a hole. 3 Before grinding and polishing use small sponge block sound tube, pay attention to: to avoid grinding and polishing the dust into the feedback words device and a microphone damage machine. And stickers to cover into the sound hole.Then cover cerumen damper. 4 polishing after the surplus with blade out pipe cut off.5.7 TestQualified to consign is used, custom machine in manufacturing complete after testing. Can be divided into the human ear audiometry and instrument test two parts.5.71 Ear audio merryAudiometry headphones sound is normal or not, will the receiver connected to the