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機(jī)械與電氣工程學(xué)院
畢業(yè)設(shè)計(jì)（論文）外文翻譯
所在學(xué)院： 機(jī)電學(xué)院
班 級(jí)： 08機(jī)自6班
姓 名： 沈玉萍
學(xué) 號(hào)： 08141010626
指導(dǎo)教師： 龔方
合作導(dǎo)師：
2011年 12 月 9 日
原文：
DESIGN AND USE OF AN EDDY CURRENT RETARDER
IN AN AUTOMOBILE
C. Y. LIU*, K. J. JIANG and Y. ZHANG
School of Automobile Engineering, Jiangsu Teachers University of Technology, Changzhou 213001, China
(Received 21 January 2010; Revised 13 December 2010)
ABSTRACT?In this study, the structure and working principles of an eddy current retarder acting as an auxiliary brake set is introduced in detail. Based on the principle of energy conservation, a mathematical model was developed to design a retarder whose nominal brake torque is 1, 900 N·m. According to the characteristics of the eddy current retarder, an exclusive test bed was developed and used for brake performance measurements. The main technical parameters, such as the brake characteristics, temperature characteristics and power consumption, were measured with the test bed. The test data show that the brake torque of the eddy current retarder obviously decreased in the continuous braking stage and that there is a certain amount of brake torque in the normal driving state because of the remnant magnetism of the rotor plate. The mathematical model could be used to design an eddy current retarder. The exclusive test bed could be used for optimization of an eddy current retarder as well as for R&D of a series of products.
KEY WORDS : Auxiliary brake, Eddy current retarder, Mathematical model, Design, Test
1. INTRODUCTION
Modern automobile design is focused on driving safety,comfort and environmental protection. With the increase in driving speeds and loads, the main brake system is no longer satisfactory for meeting the braking requirements of heavyduty vehicles and buses. Because of space constraints, it is hard to increase the braking efficiency of the main brake system through improved design. Traffic accidents usually occur when brake plates or brake drums become overheated after the main brake system has been working for a long time. This is especially true for long downhill routes.Technology laws have been put in place in many nations requiring that auxiliary braking devices must be installed for specific vehicles. Auxiliary braking devices include exhaust brakes, eddy current retarders, engine brakes and hydraulic retarders. The eddy current retarder is the most common type of auxiliary braking device.
Because it is a non-contact, continuous type of brake set,the eddy current retarder can improve comfort, especially in the automobiles used in the urban setting that need to brake frequently in the normal course of driving. This device is not used for stopping an automobile; it is only used as a complement to the main brake system. After an eddy current retarder is installed in an automobile, the frequency of main brake system use decreases, so the life of the brakes is extended. Because most of brake load is taken on by the eddy current retarder, the temperature rise in the brake disc or drum is reduced, and the braking efficiency of the main brake system is improved. Therefore, the safety of the automobile is also enhanced. Because the main brake system gets used rarely, the brake noise and dust can also be reduced, so this system benefits the environment. Currently, in heavy automobiles and large-scale passenger cars, the eddy current retarder has a standard configuration. However, the design technology of eddy current retarders needs to be perfected and developed further.
2. ANALYSIS MODEL
2.1. Structure and Working Principle An eddy current retarder is made up of eight cores, an air gap, coils and rotor plates, as shown in Figure 1. A coil is installed on the cylindrical surface of a core. The coil creates the windings. There is an even number of windings,and they are distributed equally around the circumference of the core. When the windings of the eddy current retarder are electrified, the kinetic or potential energy of the automobile can be transformed into thermal energy and dissipated into the atmosphere by a wind tunnel cast in the rotor plate, according to the electromagnetic principle.
3 TESTING AND ANALYSIS
3.1. Test-bed Structure and Operation The developed test bed was made up of a frequency conversion DC motor, a raising gearbox, an adjustable inertia flywheel group, a speed regulating device, and a series of sensors, such as a temperature sensor and a current sensor. The principle diagram of the test bed is shown in Figure 4. A DC motor was used for driving the raising gearbox. The eddy current retarder was connected with the transmission shaft. When an automobile is in a normal driving state, its kinetic energy is equivalent to the kinetic energy of the raising gearbox and the adjustable inertia flywheel group, so the developed test bed could model an automobile under different loads. Three temperature sensors were used for measuring the temperature rise of the two rotor plates and the windings. The torque and speed sensor was used for measuring the brake torque generated in the braking process and the rotational speed of the main shaft. The excitation voltage and excitation current was Figure 3. Design example of an eddy current retarder.Table 1. Calculated values of the brake characteristics for the eddy current retarder.
Characteristics Rotational speed (r/min) 200 400 600 800 1 000 1 200 Brake torque (N·m) 956 1468 1515 1529 1526 1506 Brake power (kW) 20.1 61.6 95.4 128.4 160.2 193.5 Figure 4. Principle diagram of the test bed。614 C. Y. LIU, K. J. JIANG and Y. ZHANG measured in order to study the excitation power and the power consumption characteristics of the eddy current retarder. Fans were used to simulate the wind speed in the process of running, and they also made it possible to simulate the actual thermal conditions of the eddy current retarder and could be used to cool the eddy current retarder rapidly. Test data were collected by the computercentralized control.
The test bed is shown in Figure 5. The test-bed operation process was as follows: First, the DC motor was started to drag the main shaft up to the intended rotational speed. The moment of inertia of the flywheel group was used to simulate the equivalent kinetic energy of running an automobile as an energy input of the eddy current retarder.Second, the windings were electrified in different shifts for field excitation,then the parameters, including the brake torque performance, the temperature performance and others, were measured.
3.2. Testing Capabilities and Test Items
The inertia of a 3~20 T full-load automobile could be simulated in the test bed. The rotational speed range of the main shaft was 0-3000 r/min. The following test items were performed on the test-bed. ① The brake torque rotational speed performance test: the brake torque generated by the eddy current retarder varied with the rotor speed. ② The brake torque–time characteristic, namely, the continuous brake performance test: the brake torque of the eddy current retarder varied with time at a constant rotational speed. ③ The temperature rise-time performance test: the temperature in the rotor plates and the stator changed with time as the eddy current retarder worked. ④ The brake torque-temperature performance test: the brake torque changed with temperature in the rotor plate. ⑤ The power consumption performance test: the working current and voltage in the windings varied with time as the eddy current retarder worked.
3.3.Analysis of the Test Results
The test ambient temperature was 20oC, and the air pressure was 0.1 MPa. The fourth brake shift of the retarder was used. From Figures 6 and 7, as the brake time
increased, the temperature in the rotor plate went up rapidly and then rose slowly. Joule heat generated by the eddy current in the rotor plate reached its steady state with the heat dissipating capacity of the blades. The maximum temperature on the latter rotor plate surface was approximately 505.6oC, and the temperature on the stator went up slowly compared with that on the rotor plate.When the wire was selected, a certain level of temperature tolerance must be considered.
4 CONCLUSION
A mathematical model of the eddy current retarder was developed. Based on this model, a brake torque retarder was designed. Many performance parameters were measured in an exclusive test bed. The major conclusions obtained are given below:
(1) The eddy current retarder that was designed met the requirements, which indicates that the mathematical model of brake torque developed in this study could be helpful for designing the product.
(2) Many performance parameters of the eddy current retarder could be measured in the test bed, and the test bed that was developed was based on design optimization of an eddy current retarder and R&D on a series of products.
(3) The brake torque dropped by approximately 40% after the temperature in the rotor plate reached its maximum value on the continuous stage. On the one hand, an excessive decline in the brake torque had a serious effect on the braking stability. On the other hand, the temperature rise in the rotor plate affected the life of the eddy current retarder. Meanwhile, it was adverse to safe driving. Certain actions must be taken to limit the temperature rise, such as implementing temperature
protection or time protection.
譯文：
在汽車(chē)中一個(gè)電渦流緩速器的設(shè)計(jì)與應(yīng)用
C. Y.劉*，K. J.江和Y張
中國(guó)常州江蘇技術(shù)師范學(xué)院，汽車(chē)工程學(xué)院
（2010年1月21日，2010年12月13日修訂）
摘要-在這項(xiàng)研究中,結(jié)構(gòu)和工作原理及一個(gè)電渦流緩速器制動(dòng)組表演作為一種輔助進(jìn)行了詳細(xì)的介紹。根據(jù)能量守恒原理,開(kāi)發(fā)了一個(gè)數(shù)學(xué)模型,設(shè)計(jì)了一種緩速器制動(dòng)力矩的名義為1,900 N米。根據(jù)電渦流緩速器的特點(diǎn),研制了專(zhuān)用實(shí)驗(yàn)床并用于制動(dòng)性能的測(cè)量。主要技術(shù)參數(shù),如制動(dòng)特性、溫度特性和能量消耗,與試驗(yàn)測(cè)定了床上。試驗(yàn)數(shù)據(jù)表明,制動(dòng)器制動(dòng)力矩的明顯降低電渦流緩速器制動(dòng)階段連續(xù)且有一定的制動(dòng)力矩在正常的駕駛狀態(tài)因?yàn)闅埖拇呸D(zhuǎn)子盤(pán)。該數(shù)學(xué)模型可用于電渦流緩速器設(shè)計(jì)。獨(dú)家測(cè)試床可以用于電渦流緩速器的優(yōu)化，以及用于研發(fā)的系列產(chǎn)品。
關(guān)鍵詞:輔助剎車(chē),電渦流緩速器的數(shù)學(xué)模型,設(shè)計(jì)、測(cè)試
1． 介紹
現(xiàn)代汽車(chē)的設(shè)計(jì)是集中在行車(chē)安全、舒適、環(huán)保。新增的駕駛速度和荷載作用下,不再是主要制動(dòng)系統(tǒng)的制動(dòng)要求滿(mǎn)足會(huì)議的heavyduty車(chē)輛和公共汽車(chē)。由于篇幅的限制,很難提高制動(dòng)效率的主要制動(dòng)系統(tǒng),通過(guò)完善的設(shè)計(jì)。交通事故通常發(fā)生在主剎車(chē)系統(tǒng)已經(jīng)很長(zhǎng)一段時(shí)間的工作時(shí)，剎車(chē)片或制動(dòng)鼓過(guò)熱。這尤其適用于長(zhǎng)坡的路線(xiàn)?？萍挤梢呀?jīng)到位, 需要特定的車(chē)輛必須安裝輔助制動(dòng)裝置的，許多國(guó)家尤其如此。輔助制動(dòng)裝置包括排氣制動(dòng)器，電渦流緩速器，發(fā)動(dòng)機(jī)制動(dòng)系統(tǒng)和液壓緩凝劑。電渦流緩速器輔助制動(dòng)裝置為最常見(jiàn)的類(lèi)型。
因?yàn)樗且环N非接觸式，連續(xù)式制動(dòng)設(shè)置，電渦流緩速器可以提高舒適度，尤其是在城市環(huán)境中，需要在正常駕駛過(guò)程中經(jīng)常剎車(chē)的汽車(chē)。此設(shè)備是用于停車(chē)的汽車(chē);只用它作為主剎車(chē)系統(tǒng)的補(bǔ)充。經(jīng)過(guò)電渦流緩速器是安裝在汽車(chē)的制動(dòng)系統(tǒng)使用跌幅的頻率，所以剎車(chē)的壽命延長(zhǎng)。由于大部分制動(dòng)負(fù)載是電渦流緩速，剎車(chē)盤(pán)或鼓的溫升降低，主剎車(chē)系統(tǒng)的制動(dòng)效率提高。因此，汽車(chē)的安全性也增強(qiáng)。由于主制動(dòng)系統(tǒng)很少被使用，剎車(chē)也可以減少噪音和灰塵，使這一制度有利于環(huán)境。目前，重型汽車(chē)和大型客車(chē)，電渦流緩速器的標(biāo)準(zhǔn)配置。然而，電渦流緩速器的設(shè)計(jì)技術(shù)需要進(jìn)一步完善和發(fā)展。
2． 分析模型
2.1。結(jié)構(gòu)及工作原理的電渦流緩速器是由八個(gè)內(nèi)核，氣隙，線(xiàn)圈和轉(zhuǎn)子板，如圖1所示。線(xiàn)圈安裝在圓柱表面的一個(gè)核心。線(xiàn)圈創(chuàng)建繞組。有一個(gè)繞組的偶數(shù)，和他們同樣圍繞核心的圓周分布。當(dāng)繞組的電渦流緩速器是電氣化，汽車(chē)的動(dòng)能或勢(shì)能可以轉(zhuǎn)化為熱能消散到大氣中，在轉(zhuǎn)子上的板蒙上了風(fēng)洞，根據(jù)電磁原理。
3．測(cè)試與分析
3.1試驗(yàn)臺(tái)的結(jié)構(gòu)和操作測(cè)試床是由一個(gè)直流電機(jī),變頻調(diào)速,可提高齒輪轉(zhuǎn)動(dòng)慣量飛輪組,調(diào)速裝置,以及一系列的傳感器,如溫度傳感器和一個(gè)電流傳感器。原理圖測(cè)試床被顯示在圖4。一個(gè)直流電機(jī)驅(qū)動(dòng)的用于提高變速箱。電渦流緩速器并與傳動(dòng)軸。當(dāng)一輛汽車(chē)是在一個(gè)正常的駕駛狀態(tài),其動(dòng)能等效為動(dòng)能增加變速箱和可調(diào)整的慣性飛輪集團(tuán),所以發(fā)達(dá)測(cè)試床可以在不同負(fù)荷模型汽車(chē)。三個(gè)溫度傳感器,用于測(cè)量的兩個(gè)轉(zhuǎn)子溫升板和繞組。的扭矩和速度傳感器用于測(cè)量制動(dòng)器制動(dòng)力矩和制動(dòng)過(guò)程中產(chǎn)生的主軸轉(zhuǎn)速。激勵(lì)電壓和勵(lì)磁電流圖3。設(shè)計(jì)一個(gè)電渦流緩速器的例子。表1。理論計(jì)算的制動(dòng)特性的電渦流緩速器。
特性轉(zhuǎn)速（轉(zhuǎn)/分）200 400 600800 1 0001200制動(dòng)力矩（牛頓?米）95614681515152915261506制動(dòng)功率（kW）20.161.695.4128.4160.2193.5圖4。 614 CY劉江，KJ和Y張?jiān)韴D的試驗(yàn)床。測(cè)量，以研究的勵(lì)磁功率和電渦流緩速器的功耗特性。球迷們用來(lái)模擬在運(yùn)行過(guò)程中的風(fēng)速，他們還提出了它可以模擬電渦流緩速器的實(shí)際熱條件，可用于電渦流緩速迅速冷卻。測(cè)試數(shù)據(jù)收集由計(jì)算機(jī)集中控制。
測(cè)試床如圖5所示。試驗(yàn)臺(tái)的操作過(guò)程如下：首先，開(kāi)始拖動(dòng)直流電動(dòng)機(jī)主軸轉(zhuǎn)速達(dá)到了預(yù)期的。慣性飛輪組的時(shí)候，是用來(lái)模擬運(yùn)行作為汽車(chē)電渦流緩速器的能量輸入相當(dāng)于動(dòng)能。二，繞組在倒班工作現(xiàn)場(chǎng)勵(lì)磁,然后參數(shù),包括制動(dòng)器制動(dòng)力矩性能、溫度特性以及其他人都進(jìn)行了測(cè)量。
3.2 測(cè)試能力和測(cè)試項(xiàng)目
3?20噸的滿(mǎn)負(fù)荷的汽車(chē)的慣性可以在模擬試驗(yàn)臺(tái)。主軸轉(zhuǎn)速范圍0-3000轉(zhuǎn)/分。下面的測(cè)試項(xiàng)目進(jìn)行測(cè)試床。 ①制動(dòng)轉(zhuǎn)矩轉(zhuǎn)速性能測(cè)試:制動(dòng)器制動(dòng)力矩產(chǎn)生的電渦流緩速器轉(zhuǎn)子速度不同。②制動(dòng)轉(zhuǎn)矩時(shí)的特點(diǎn)，即連續(xù)制動(dòng)性能測(cè)試:制動(dòng)器制動(dòng)力矩的電渦流緩速器性能隨時(shí)間在恒定轉(zhuǎn)速上升。③溫度性能測(cè)試溫度在轉(zhuǎn)子和定子板隨時(shí)間不斷變化的電渦流緩速器的制動(dòng)轉(zhuǎn)矩溫度。④工作性能測(cè)試:制動(dòng)器制動(dòng)力矩隨溫度變化在轉(zhuǎn)子盤(pán)。⑤電耗性能測(cè)試:工作電流、電壓隨時(shí)間在繞組電渦流緩速器的工作。
3.3測(cè)試結(jié)果分析
測(cè)試環(huán)境溫度為20℃，空氣壓力為0.1 MPa。第四緩速制動(dòng)轉(zhuǎn)向使用。從圖6和7的制動(dòng)時(shí)間增加，在轉(zhuǎn)子盤(pán)的溫度上升迅速，然后緩慢上升。由渦流產(chǎn)生的焦耳熱轉(zhuǎn)子盤(pán)與刀片的散熱能力達(dá)到穩(wěn)定狀態(tài)。后者轉(zhuǎn)子鋼板表面的最高溫度約為505.6攝氏度，定子溫度上升緩慢相比，轉(zhuǎn)子盤(pán)電線(xiàn)被選中，一定程度的溫度公差必須考慮。
4結(jié)論
電渦流緩速器的一個(gè)數(shù)學(xué)模型的開(kāi)發(fā)?；谶@個(gè)模型，設(shè)計(jì)一個(gè)制動(dòng)力矩緩速。許多性能參數(shù)測(cè)定在專(zhuān)用的試驗(yàn)床。所取得的主要結(jié)論如下：
（1）電渦流緩速器的設(shè)計(jì)符合要求，這表明，在這項(xiàng)研究中開(kāi)發(fā)的制動(dòng)力矩的數(shù)學(xué)模型可能有助于設(shè)計(jì)的產(chǎn)品。
（2）許多性能參數(shù)可以衡量電渦流緩速器性能的測(cè)試,并對(duì)試驗(yàn)床床上進(jìn)行開(kāi)發(fā)的基于優(yōu)化設(shè)計(jì)的電渦流緩速器和研發(fā)的一系列產(chǎn)品。
（3）制動(dòng)力矩在轉(zhuǎn)子板后溫度下降約40％，達(dá)到連續(xù)舞臺(tái)上的最大價(jià)值。一方面，在制動(dòng)力矩的過(guò)度下降嚴(yán)重影響了制動(dòng)穩(wěn)定性。另一方面，在轉(zhuǎn)子盤(pán)的溫度上升影響電渦流緩速器的使用壽命。同時(shí)，對(duì)安全駕駛不利。必須采取某些行動(dòng)限制溫度的上升,實(shí)現(xiàn)溫度等。