傳統車輛煞車盤冷卻流道之熱傳實驗研究

Experimental Study of Heat Transfer on Cooling Passage of Traditional Vehicle Braking Disc

蘇宏明(Hung-Ming Su) ； 葉致廷(Chih-Ting Yeh) ； 陳易辰(Yi-Chen Chen)

《建國科大學報》 29卷3期 (2010/04) Pp. 81-96

https://doi.org/10.6995/JCTU.201004.0081

摘要

車輛的制動盤是靠著煞車卡鉗來夾住煞車碟盤，利用「摩擦」的作用，完成制動車輛的工作，過程中動能因摩擦而轉化為熱能。車輛以正常速度行駛時，其煞車片與煞車碟盤之間的作動溫度約在100~180℃，如果是高速行駛時作動溫度甚至高達180~400℃，此高溫之形成主要是由摩擦所造成，摩擦力的大小是與摩擦係數及摩擦面所受垂直方向的正壓力的乘積成正比，當摩擦係數越大，所產生的摩擦力就越大，但是來令片與碟盤間的摩擦係數會因摩擦後所產生的高熱而降低，因此煞車制動力要求愈高，煞車碟盤的散熱能力也就要愈佳，才能提升行車安全。煞車碟盤的散熱是藉由週遭的空氣進行熱交換，希望熱傳效率提升，以提升行車之穩定性，煞車碟盤的表面積就要愈大或從煞車碟盤中央作強制冷卻，才能增加煞車的安全性。因此本研究將以實驗方法，研究制動盤通風管道之散熱情形，為了能夠增加實驗之真實性及準確性，運用電木製作一個與車輛上原尺寸相同之通風碟，並利用此徑向旋轉通道進行實驗，並分析冷卻通道之單位面積內所能夠帶走之熱通量，以了解制動盤內部冷卻通道之各測溫點受到旋轉流場效應之熱傳分佈及影響，藉由此實驗能夠讓我們更了解在各種車速下制動盤通風碟之熱傳特性。

關鍵字

制動盤 ； 摩擦 ； 熱傳

並列摘要

The brake disc of vehicles allows the brake caliper to clamp it for braking the vehicles through a friction action, during which the kinetic energy is converted into heat energy. When the vehicles are running at a normal speed, the brake pad and brake disc are operated at approx. 100~180℃, or even up to 180~400℃ in the event of high-speed running, primarily due to the friction between them. The friction is proportional to the product of the friction coefficient and the positive pressure applied vertically to the frictional surface. A larger friction coefficient means a larger frictional force; however, the friction coefficient between the brake pad and brake disc will decrease with growing temperature generated from friction. Thus, a higher braking force and better heat-sinking capability of brake disc will be required to improve the running safety. The heat-sinking of the brake disc is conducted through heat exchange of ambient air to improve the heat transfer efficiency and running stability, while a larger surface area of brake disc is required, or otherwise forced cooling will be effected at the center of the brake disc to promote the braking safety. This study aims to examine the heat-sinking conditions in the ventilating duct of the brake disc to increase the authenticity and accuracy; then a ventilating disc of the same size is fabricated by bakelite to conduct experiment with this radial rotary duct, and analyze the heat flux in the unit area of the cooling channel, so as to learn the heat transfer distribution and influences of temperature measurement points in the cooling channel within the rotary flow field. The experimental results can provide further understanding on the heat transfer characteristics of ventilating disc of brake disc at various speeds.

並列關鍵字

brake disc ； friction ； heat transfer