成人抖抈app免费版,校园春色激情五月天,免费性爱一级视频,av污污污

During normal use, the piston rod bears alternating loads, φ 50mm × There is a sealing device at 770mm that rubs its surface back and forth, so it requires high hardness and wear resistance. Its structure is relatively simple, but it has a large aspect ratio. In specific cases, it belongs to the slender shaft type component and has poor rigidity. In order to ensure machining accuracy, coarse and fine turning should be separated during turning, and both coarse and fine turning should use a tool holder to reduce the deformation of the workpiece during processing. When machining the threads at both ends, a center holder should be used.
When selecting the positioning reference for the piston rod, in order to ensure the coaxiality tolerance of its components and the mutual position accuracy of each part, the machining process adopts two center holes for positioning, in accordance with the principle of unified reference.
To ensure the stability of piston rod accuracy during use, manual straightening is not allowed throughout the entire machining process. During nitriding treatment, threaded parts, etc., should be protected with protective devices. It adopts rolling processing, and due to the residual compressive stress left on the surface layer, it is conducive to the sealing of small surface cracks and hinders the expansion of erosion. This enhances the surface corrosion resistance and can delay the generation or expansion of fatigue cracks, thereby increasing the fatigue strength of the cylinder rod.