نقش دما در خرابی های زودرس سیستم های هیدرولیک

 

High hydraulic fluid temperature - how it causes premature failures

I was asked recently to conduct failure analysis on two radial piston hydraulic motors that had failed well short of their expected service life. Inspection revealed that the motors had failed through inadequate lubrication, as a result of low fluid viscosity caused by excessive hydraulic fluid temperature.

How does this happen?

As the temperature of petroleum-based hydraulic fluid increases, its viscosity decreases. If fluid temperature increases to the point where viscosity falls below the level required to maintain a lubricating film between the internal parts of the component, damage will result.

The temperature at which this occurs depends on the viscosity grade of the fluid in the system. Hydraulic fluid temperatures above 180°F (82°C) damage seals and reduce the service life of the fluid. But depending on the grade of fluid, viscosity can fall to critical levels well below this temperature.

مشخصات لاستیک

 

روی دیواره بیرونی هر تایر، اعداد و کدهای درج شده است که در حقیقت شناسنامه  لاستیک خودرو هستند. در شکل مفهوم این علائم بیان شده است. در ادامه به شرح برخی از مهمترین آنها می­پردازیم.

  الف) اندازه تایر

    اندازه لاستیک خودرو با علائمی 

    همچون4P185/60R13

   نشانداده می‌شود.

   که بدین معنی میباشد:

 P     = تایر خودروی شخصی

     185= پهنای تایر

      (برحسب میلی­متر)

آیا شارژ نیتروژن در لاستیک بهتراز هواست

Nitrogen: A Noble Gas?

As you can see, there are days when you just have to get your car off the ground and this was one of those days as the Altima was due for a tire rotation. My buddies up at Tire Town have taught me well and I religiously rotate my tires every 6000 miles, no longer than that, and it really seems to have worked as I'm usually getting in the neighborhood of 45,000 miles out of a set of tires.

We put a lot of miles on our vehicles. The 2001 Altima currently has 135,000 miles on it so preventive maintenance is something I believe in.

This year there's a new addition to the equipment in the garage and they have installed a system for filling tires with nitrogen. It's a clever machine in that it filters the air to collect the nitrogen it uses, so there are no compressed gas cylinders to be delivered or tanks to have filled up. Nitrogen makes up about 78.1% of the atmoshphere by volume, so there's plenty of it to go around. One of the reasons they installed the system was because of the consumer interest that was generated by the claims being made about using nitrogen in your tires.

Get Nitrogen Institute: