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機械與電氣工程學院
畢業(yè)設計（論文）外文翻譯
所在學院： 機電學院
班 級： 08機自6班
姓 名： 沈玉萍
學 號： 08141010626
指導教師： 龔方
合作導師：
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：
在汽車中一個電渦流緩速器的設計與應用
C. Y.劉*，K. J.江和Y張
中國常州江蘇技術(shù)師范學院，汽車工程學院
（2010年1月21日，2010年12月13日修訂）
摘要-在這項研究中,結(jié)構(gòu)和工作原理及一個電渦流緩速器制動組表演作為一種輔助進行了詳細的介紹。根據(jù)能量守恒原理,開發(fā)了一個數(shù)學模型,設計了一種緩速器制動力矩的名義為1,900 N米。根據(jù)電渦流緩速器的特點,研制了專用實驗床并用于制動性能的測量。主要技術(shù)參數(shù),如制動特性、溫度特性和能量消耗,與試驗測定了床上。試驗數(shù)據(jù)表明,制動器制動力矩的明顯降低電渦流緩速器制動階段連續(xù)且有一定的制動力矩在正常的駕駛狀態(tài)因為殘的磁轉(zhuǎn)子盤。該數(shù)學模型可用于電渦流緩速器設計。獨家測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,電渦流緩速器的數(shù)學模型,設計、測試
1． 介紹
現(xiàn)代汽車的設計是集中在行車安全、舒適、環(huán)保。新增的駕駛速度和荷載作用下,不再是主要制動系統(tǒng)的制動要求滿足會議的heavyduty車輛和公共汽車。由于篇幅的限制,很難提高制動效率的主要制動系統(tǒng),通過完善的設計。交通事故通常發(fā)生在主剎車系統(tǒng)已經(jīng)很長一段時間的工作時，剎車片或制動鼓過熱。這尤其適用于長坡的路線。科技法律已經(jīng)到位, 需要特定的車輛必須安裝輔助制動裝置的，許多國家尤其如此。輔助制動裝置包括排氣制動器，電渦流緩速器，發(fā)動機制動系統(tǒng)和液壓緩凝劑。電渦流緩速器輔助制動裝置為最常見的類型。
因為它是一種非接觸式，連續(xù)式制動設置，電渦流緩速器可以提高舒適度，尤其是在城市環(huán)境中，需要在正常駕駛過程中經(jīng)常剎車的汽車。此設備是用于停車的汽車;只用它作為主剎車系統(tǒng)的補充。經(jīng)過電渦流緩速器是安裝在汽車的制動系統(tǒng)使用跌幅的頻率，所以剎車的壽命延長。由于大部分制動負載是電渦流緩速，剎車盤或鼓的溫升降低，主剎車系統(tǒng)的制動效率提高。因此，汽車的安全性也增強。由于主制動系統(tǒng)很少被使用，剎車也可以減少噪音和灰塵，使這一制度有利于環(huán)境。目前，重型汽車和大型客車，電渦流緩速器的標準配置。然而，電渦流緩速器的設計技術(shù)需要進一步完善和發(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內(nèi)核，氣隙，線圈和轉(zhuǎn)子板，如圖1所示。線圈安裝在圓柱表面的一個核心。線圈創(chuàng)建繞組。有一個繞組的偶數(shù)，和他們同樣圍繞核心的圓周分布。當繞組的電渦流緩速器是電氣化，汽車的動能或勢能可以轉(zhuǎn)化為熱能消散到大氣中，在轉(zhuǎn)子上的板蒙上了風洞，根據(jù)電磁原理。
3．測試與分析
3.1試驗臺的結(jié)構(gòu)和操作測試床是由一個直流電機,變頻調(diào)速,可提高齒輪轉(zhuǎn)動慣量飛輪組,調(diào)速裝置,以及一系列的傳感器,如溫度傳感器和一個電流傳感器。原理圖測試床被顯示在圖4。一個直流電機驅(qū)動的用于提高變速箱。電渦流緩速器并與傳動軸。當一輛汽車是在一個正常的駕駛狀態(tài),其動能等效為動能增加變速箱和可調(diào)整的慣性飛輪集團,所以發(fā)達測試床可以在不同負荷模型汽車。三個溫度傳感器,用于測量的兩個轉(zhuǎn)子溫升板和繞組。的扭矩和速度傳感器用于測量制動器制動力矩和制動過程中產(chǎn)生的主軸轉(zhuǎn)速。激勵電壓和勵磁電流圖3。設計一個電渦流緩速器的例子。表1。理論計算的制動特性的電渦流緩速器。
特性轉(zhuǎn)速（轉(zhuǎn)/分）200 400 600800 1 0001200制動力矩（牛頓?米）95614681515152915261506制動功率（kW）20.161.695.4128.4160.2193.5圖4。 614 CY劉江，KJ和Y張原理圖的試驗床。測量，以研究的勵磁功率和電渦流緩速器的功耗特性。球迷們用來模擬在運行過程中的風速，他們還提出了它可以模擬電渦流緩速器的實際熱條件，可用于電渦流緩速迅速冷卻。測試數(shù)據(jù)收集由計算機集中控制。
測試床如圖5所示。試驗臺的操作過程如下：首先，開始拖動直流電動機主軸轉(zhuǎn)速達到了預期的。慣性飛輪組的時候，是用來模擬運行作為汽車電渦流緩速器的能量輸入相當于動能。二，繞組在倒班工作現(xiàn)場勵磁,然后參數(shù),包括制動器制動力矩性能、溫度特性以及其他人都進行了測量。
3.2 測試能力和測試項目
3?20噸的滿負荷的汽車的慣性可以在模擬試驗臺。主軸轉(zhuǎn)速范圍0-3000轉(zhuǎn)/分。下面的測試項目進行測試床。 ①制動轉(zhuǎn)矩轉(zhuǎn)速性能測試:制動器制動力矩產(chǎn)生的電渦流緩速器轉(zhuǎn)子速度不同。②制動轉(zhuǎn)矩時的特點，即連續(xù)制動性能測試:制動器制動力矩的電渦流緩速器性能隨時間在恒定轉(zhuǎn)速上升。③溫度性能測試溫度在轉(zhuǎn)子和定子板隨時間不斷變化的電渦流緩速器的制動轉(zhuǎn)矩溫度。④工作性能測試:制動器制動力矩隨溫度變化在轉(zhuǎn)子盤。⑤電耗性能測試:工作電流、電壓隨時間在繞組電渦流緩速器的工作。
3.3測試結(jié)果分析
測試環(huán)境溫度為20℃，空氣壓力為0.1 MPa。第四緩速制動轉(zhuǎn)向使用。從圖6和7的制動時間增加，在轉(zhuǎn)子盤的溫度上升迅速，然后緩慢上升。由渦流產(chǎn)生的焦耳熱轉(zhuǎn)子盤與刀片的散熱能力達到穩(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)子盤電線被選中，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數(shù)學模型的開發(fā)。基于這個模型，設計一個制動力矩緩速。許多性能參數(shù)測定在專用的試驗床。所取得的主要結(jié)論如下：
（1）電渦流緩速器的設計符合要求，這表明，在這項研究中開發(fā)的制動力矩的數(shù)學模型可能有助于設計的產(chǎn)品。
（2）許多性能參數(shù)可以衡量電渦流緩速器性能的測試,并對試驗床床上進行開發(fā)的基于優(yōu)化設計的電渦流緩速器和研發(fā)的一系列產(chǎn)品。
（3）制動力矩在轉(zhuǎn)子板后溫度下降約40％，達到連續(xù)舞臺上的最大價值。一方面，在制動力矩的過度下降嚴重影響了制動穩(wěn)定性。另一方面，在轉(zhuǎn)子盤的溫度上升影響電渦流緩速器的使用壽命。同時，對安全駕駛不利。必須采取某些行動限制溫度的上升,實現(xiàn)溫度等。