In addition to threaded pipe nipples, there are other methods to connect two or more parts, such as welding, riveting, and glueing to form a joint. Why are the joints in automobile design mainly threaded pipe joints?
1. Threaded pipe nipples can save automobile costs;
2. Can be used for large-scale production (for example, a factory will assemble 1 million joints/1000 vehicles every day);
3. Easy to disassemble during maintenance.
In comparison, the use of threaded pipe nipples is better than other connection methods.
1. Used for oil drain plug bolt joint of old gearbox. The significance of this joint is to facilitate the flow of the old gearbox oil, so it needs to ensure the flow rate of the oil, and it needs to achieve the sealing function of the tightened state. This determines that the size of the threaded holes and bolts in the shell cannot be too small; and the sealing function needs to be solved by gaskets.
2. Easy to assemble. Take the upper control arm to the wheel bracket joint as an example. When designing, it should be considered that the joint is not blocked by other parts, so that the rear upper control arm can be easily replaced.
3. Easy to identify when failure occurs. Continue to the rear upper control arm to the wheel bracket joint. If you look carefully at the operation process, there is a flower-shaped washer under the nut, its function is to prevent the direct separation between the upper control arm and the wheel bracket after the bushing fails. Assuming that the bushing fails, there will be abnormal noise between the rear upper control arm and the wheel bracket, which is convenient for the driver to tighten the threaded pipe joints.
At present, the torque method and the torque angle method are most used in the automotive industry. The torque method is a method of applying a certain torque to the fastener to tighten it. The torque angle method is based on the torque method, and then tighten a certain angle.