How to calculate retaining ring maximum speed (rpm), and when it matters

选择适当的挡环对于应用通常涉及评估诸如安装应力的因素，由环施加的径向载荷和环的推力容量。并且因为保持环的凹槽与环形性能成一体，所以也需要考虑凹槽变形。

但是，当外部保持环在旋转轴上使用时，离心力会导致环抬起其凹槽，导致环形故障，因此最大速度也成为重要的选择因子。

high speed retaining ring — To withstand high speeds and centrifugal forces, this retaining ring has a “self-locking” mechanism consisting of a dome and a slot, which limits how far the ring can expand.
*图像信用：smalley*

The maximum speed that an external retaining ring can withstand is the speed at which the force holding the ring in its groove becomes zero, and is determined by the ring’s material properties and size.

N=最大转速（RPM）

3600= conversion from rotations per second to rotations per minute (square root of 3600 = 60)

V= radial interference between ring and groove, also referred to as “cling” (in)

D_G=凹槽直径（in）

D_I=圈内径（in）

I=平面惯性矩（在⁴)

因为环有一个矩形横截面，所以我们使用planar moment of inertia(also referred to as second moment of area)formula for a rectangle，使用环的厚度和截面宽度作为矩形的基础和高度。

t= ring thickness (in)

b= ring radial section width, or wall (in)

E=弹性模量（PSI）= 29 x 10⁶Psi（对于大多数钢，不包括不锈钢合金）

g= acceleration due to gravity (in/s²）= 386.4 IN / s²

4π²=转换成扭转的因素（4π的平方根²= 2π, which is the number of radians in one revolution)

Y= factor for number of turns (1 turn = 1.909, 2 turns = 3.407, 3 turns = 4.958)

Spiral retaining rings can have more than one turn, or coil, around the ring’s diameter. Typicalconstant section and tapered ringshave only one turn, so for these designs, the factor for one turn (1.909) is used.

γ.=材料密度（LB / IN³）= 0.283磅/ in³（对于大多数钢，不包括不锈钢合金）

A= cross-sectional area (in²)

R_m=均值自由半径（in）

For retaining rings made of most steels and steel alloys, except stainless versions, the known quantities can be combined, and the equation can be simplified to:

请注意，在分母中，我们使用了卑鄙diameter, rather than the meanradius.

D_m=平均直径（in）

interlocking retaining ring — 在这里,两半assemb时联锁led to prevent the ring from expanding in high-speed operation.
*图像信用：转子夹*

To address applications that run at high speed, retaining ring manufacturers have developed external rings with self-locking features that prevent the ring from failing, even under high centrifugal forces.

One design, used for spiral-wound retaining rings, incorporates a raised dome on the inside turn of the ring and a slot on the outside turn. As speed increases and the ring begins to expand, the dome slides along the slot, and the length of the slot limits the amount by which the ring can expand. Another design, used on traditional retaining rings, features a two-piece ring whose ends interlock when assembled onto a shaft, preventing the ring from expanding.