Clamping Method Of Piston Pin Bore In Gun Drilling Machine Tool
Jan 23, 2019

Piston pin is one of the important parts of automobile engine. The main processing procedure of this part in gun drilling machine tool is drilling the inner hole. Refer to the following drawings for part drawings.


Four workpieces can be clamped at a time when the hole is machined by a four-axis NC gun drilling machine tool. The processing efficiency is very high.

Usually, two inner cone top plates are used to clamp the workpiece in the gun drilling machine tool, and the outer circle chamfer at both ends of the workpiece is clamped by hydraulic pressure. The clamping position is accurate and highly automated, so it is widely used.

However, for the clamping of piston pin parts, because of its special process arrangement, the preceding process of deep hole processing is to cut a whole material in segments with a numerical control band saw and convey it to the gun drilling machine through conveyor belt. The workpiece's outer circle has no chamfer, and the verticality between the two ends of the workpiece cut by the saw machine and the outer circle of the workpiece is very poor. If the workpiece is clamped in the form of two inner cone top plates and two top plates, unreliable clamping and low positioning accuracy will occur, resulting in unstable processing and high rejection rate.

If the chuck is used to clamp the workpiece's outer circle, it can avoid the shortcomings of inaccurate positioning and unreliable clamping, but the clamping automation of machine tools is relatively difficult to achieve, which requires manual loading and unloading of workpieces. It is disadvantageous to improve production efficiency.

In view of the above problems, we have designed a set of fittings which are very suitable for piston pin clamping.See the following figure for the structural form:


1. The left and right ends of the workpiece are clamped in the form of cylinder clamps. The outer circles of the left and right ends of the workpiece are clamped, and the clamping length of each end is about 10 mm.

2. The clamping power of cylinder clamp is hydraulic jacking.

3. The workpiece is first placed on the "V" auxiliary bracket, and the center height of the "V" bracket is adjusted to make the workpiece and the clamp concentric.

4. Hydraulic drive of the left clip, extending from left to right, sleeves the left end of the workpiece into the inner hole of the clip, and continues to move the workpiece to the right, pushing the workpiece into the inner hole of the right clip. The spring sleeve of the cylinder clamp shrinks and clamps the workpiece.

5. After deep hole processing, the left clamp recedes, the left and right clamps are loosened, and the workpiece falls on the "V" bracket. Complete workpiece loading and unloading and processing cycle.

The double cylinder clamp can directly clamp the outer circle of the piston pin, and the positioning is accurate and reliable. In addition, it is very suitable for automatic transmission of workpiece with conveyor belt.

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