What Is a Knock Pin?
A knock pin is a type of jig specifically used to ensure the assembly accuracy of industrial products.
Knock pins are employed in joints requiring particularly high assembly accuracy during overhaul of industrial products, and in addition to serving as guides during jointing, they prevent misalignment during assembly and misalignment caused by external shocks.
Typically, two knock pins are utilized for each joint.
Uses of Knock Pins
Knock pins are utilized for joining parts that necessitate high-precision positioning. In particular, they are often used in automotive parts.
Specific uses of knock pins are as follows:
- Joints between cylinder heads and cylinder blocks (crankcases)
- Joints between engines and transmissions (clutch housings and torque converter housings)
- Joints between differential gears and axle housings, etc.
In addition, knock pins are also used on the mating surfaces of rotating parts, drive parts, and other parts that transmit power.
Principles of Knock Pins
Knock pins are designed to prevent misalignment in the radial direction (perpendicular to the axis). Generally, a single knock pin will cause misalignment at its fulcrum, so two or more pins are used at equal or diagonal intervals. Since the pin diameter tolerance is set only on the positive side and the use of press-fitting is assumed, a more precise assembly can be performed than with parallel pins.
Other Information on Knock Pins
1. Precautions for Using Knock Pins
When removing and reinstalling parts with knock pins, the knock pins may be pulled out together. When reassembling, it is necessary to check that the knock pins are properly inserted all the way to the back before reassembling.