Design Change Enables Two Pumps to Use One Type of Coiled Pin

卷绕销将轴固定在海洋泵设计中的转子。

对于新的海洋泵设计，轴/转子暴露于20英尺/磅的扭矩。泵设计师希望确保正确的引脚选择以吸收额外的扭矩。他想在两个应用中使用相同的PIN，但在试验中使用新的泵设计引脚剪切。Spirol应用工程师评估了新泵，发现多个设计元素在销上放置额外的剪切力，这可以通过以下变化减少：

– the relationship between the Shaft OD and the rotor ID be changed to have a maximum clearance of 0.005 in., which minimizes the shear plane between the two;
- 将剪切平面远离引脚的末端移动到至少一个直径长度（当前0.125英寸），这确保了销与孔牢固地界面而无需显着运动;
– eliminate the lead-in on the aluminum shaft which contributes to a poor shear plane at the shaft/rotor joint.

Analysis of a new pump design, though, showed the need to adjust the shear planes.


基于螺旋应用工程师的建议，设计的变化使设计工程师使用小直径的卷材引脚。

The application engineers also suggested a change to the pin. In this case the pin is installed in a soft aluminum shaft. During cycling, the heavy-duty Ø.187 pin, which is a strong yet least flexible coiled pin, breaks down the edge of the hole on the aluminum shaft deteriorating the shear plane.

Heavy-duty pins are not recommended for use in soft materials. The application engineer recommended that the customer move to a more flexible coiled pin, which in this case was the standard duty pin. The increased flexibility protects the soft material by allowing the pin to absorb the dynamic forces rather than transmitting them to the host. Additionally, by correcting the shear plane issues above, the customer could move to a smaller diameter Ø.125 in. pin.

通过这些建议，设计工程师可以在两个应用中使用相同的引脚，降低轴上的引线的加工成本，并降低组装中销的成本。

Spirol International Corp.
www.spirol.com