What is the n×dm speed factor?

n×dm is the product of rotational speed (RPM) and mean bearing diameter dm = (d+D)/2 in mm. It is a key parameter for assessing whether a bearing can operate at a given speed with grease or oil lubrication.

Is there a universal n×dm grease limit?

No. Permissible speed and grease suitability depend on the exact bearing design, size, cage, seals, clearance, load, temperature, lubricant and heat dissipation. Use the current product table and lubricant data.

Can n×dm alone select grease or oil?

No. n×dm is a useful speed parameter, but lubrication selection also requires the exact bearing, load, operating temperature, viscosity, grease performance, relubrication method and thermal design.

Where should I obtain the limiting speed?

Use the limiting and reference speeds published for the exact bearing designation and execution by its manufacturer. A bearing-family name alone is insufficient.

Does a low n×dm prove the application is safe?

No. n×dm does not check load, minimum load, cage stress, lubrication film, temperature, clearance, sealing, alignment or critical speed. It is only one input to bearing selection.

免費工程工具 #053

軸承速度係數 n×d_m 計算器

計算平均直徑 d_m 與速度係數 n×d_m。僅將結果與特定軸承和潤滑劑的資料進行比較。

n × dm經驗證的公式需參考製造商極限

結果

速度係數 n × dm

—

平均直徑 dm

—

速度係數公式

解讀

n×d_m 是用於潤滑劑與再潤滑指導的速度參數。它並非軸承極限速度，也不能單獨決定使用潤滑脂還是潤滑油。請使用當前製造商文件中的確切軸承型號、規格、保持架、密封件、負載、溫度和潤滑劑。

對於外圈旋轉或特殊配置，製造商可能會指定不同的速度參數或修正係數。請遵循該定義，而非假設 n×d_m.

軸承速度係數 n×dm 計算機 | 潤滑脂與潤滑油極限 | 免費線上工具

結果

速度係數公式

解讀

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