液壓煞車裝置散熱系統之研製及改善

Implementation and Improvement of the Cooling System of Hydraulic Brake

翁原鴻(Yuan-Hong Wong)

指導教授 ： 邱國珍

國立虎尾科技大學/電機資訊學院/電機工程系碩士在職專班/碩士(2017年)

摘要

本論文關於密閉型液壓煞車裝置散熱系統之研究，密閉型液壓煞車裝置透過齒輪泵運轉產生吸引及排出帶動循環油流動，密閉型液壓煞車裝置採用密閉循環管路構造，齒輪泵長時間運轉後產生熱能，導致循環油溫度持續升溫，油溫的升高促使循環油黏度下降，油膜遭到破壞，使機件增加摩擦阻力，造成齒輪間隙變化，齒輪泵容積改變形成困油現象產生極高壓力及局部真空讓循環油氣、液分離，產生氣穴現象，這些都會為齒輪泵帶來振動及循環油洩漏，造成齒輪泵軸心不平衡，機件卡死問題發生引起機件發熱，造成整個液壓系統效率顯著下降，循環油也會變質呈現酸性進一步腐蝕設備及管路。本論文針對解決液壓煞車過熱之問題設計出散熱系統，利用熱傳導原理之熱物體接觸冷物體，熱能便能從熱物體傳導至冷物體，並藉由熱對流原理使用循環水快速帶走熱量，有效壓制循環油的溫度。透過各種散熱系統實驗比較後，水循環散熱系統確實較自然散熱方式具有更佳的散熱效果，其中冰水循環系統較自然散熱方式循環油降低9.3，齒輪泵溫度降低8.9最有效率降低液壓煞車的齒輪泵溫度及循環油升溫的問題，惟其缺點是設備因需置放壓縮機較佔用空間、成本昂貴、電力上的消耗。另熱減少散熱系統較自然散熱方式，循環油降低27.6，齒輪泵溫度降低4.5，不過因熱減少散熱系統運轉時齒輪泵無循環油流入，因其無法即時提供循環油進行煞車，需有蓄壓器輔助煞車，即能發揮煞車功能，其優點是減少散熱系統利用電磁閥阻斷循環油置留於油箱，當有需要煞車時才釋放循環油，循環有大部分時間均置留在油箱內，循環油不會因溫度變化而產生變質；氣冷式水循環系統，實驗結果較自然散熱方式循環油降低4.8，齒輪泵溫度降低3.8；水冷式水循環系統，實驗結果較自然散熱方式循環油降低3.5，齒輪泵溫度降低3.2，氣冷式水循環系統及水冷式水循環系統，散熱效果與自然散熱方式相較之下油溫及齒輪泵溫度雖有降低，由於纏繞於在油管上的傳熱管應受熱面積不足及循環水與油溫溫度差異過小，導致散熱效果相較熱減少散熱系統差。

關鍵字

液壓煞車 ； 散熱系統 ； 齒輪泵 ； 熱減少 ； 蓄壓器 ； 水循環

並列摘要

This thesis is based on the study of cooling system of the closed type hydraulic brake. The closed type hydraulic brake adopts the closed type circulation tube, which runs by the gear pump to generate positive and negative pressure to produce circulation oil flow. However, after running in a long period of time, the gear pump generates heat energy and results in the temperature rise of circulation oil, in addition, the rising temperature will reduce the viscosity of circulation oil, causing damage to the oil film and increasing friction drag of machine parts. These will also give rise to the change of the clearances of gears and the volume of gear pump, In this situation, the circulation oil flow will be obstructed, which will produce extreme high pressure and partial vacuum, and most importantly, the air pocket phenomenon. The fore-mentioned factors would cause various problems, such as increasing vibration of gear pump and leakages of circulation oil, unbalanced axle center, malfunction, reducing the efficiency of hydraulic system, and acidity of circulation oil that will even made the whole equipment been corroded. Therefore, this thesis focus on solving the problem of overheating in hydraulic brake system, by applying the heat conduction and heat convection principle to reduce the temperature of circulation oil more efficiently. In the experiments of five different types of cooling system, which are “heat energy reduce” cooling system, “iced-water” cooling system, “air-cooled” cooling system, “water-cooled” cooling system and natural heat dissipation. For cooling effectiveness, it shows that the water circulation cooling system is obviously superior to the situation under natural heat dissipation. This thesis takes natural heat dissipation as a comparison basis, For the temperature of oil circulation, “heat energy reduce” cooling system dropped by 27.6, “iced-water” cooling system dropped by 9.3, “air-cooled” cooling system dropped by 4.8, and “water-cooled” cooling system dropped by 3.5. On the other hand, for the temperature of gear pump, “heat energy reduce” cooling system dropped by 4.5, “iced-water” cooling system dropped by 8.9, “air-cooled” cooling system dropped by 3.8, and “water-cooled” cooling system dropped by 3.2. In conclusion, the “iced-water” cooling system is the most efficient system. However, there are apparent disadvantages. For example, it needs more space to place the compressor, higher costs and electricity consumption. On the other hand, the “heat energy reduce” requires fewer installation space, lower costs and energy consumption. Therefore, it achieves highest economic benefits and will be in widespread use.

並列關鍵字

hydraulic brake ； cooling system ； gear pump ； heat energy reduce ； accumulator ； water circulation

參考文獻

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