Inner sleeve for a flat extrusion cylinder and a flat extrusion cylinder

Abstract

An inner sleeve for a flat extrusion cylinder includes an inner sleeve ring piece, an upper insert piece and a lower insert piece. The inner sleeve ring piece is positioned in an intermediate sleeve of the flat extrusion cylinder. The upper insert piece and the lower insert piece are symmetrically disposed on an inner wall of the inner sleeve ring piece to form an inner sleeve working die cavity of the flat extrusion cylinder. Arc surfaces of two insert pieces match with the arc inner wall of the inner sleeve ring piece, so as to improve the stress distribution at interface portions between the flat surface and the arc surface of the inner sleeve working die cavity. When the flat extrusion cylinder is operated, the insert pieces will make a minor displacement in upward and downward direction due to the pressure from the inner sleeve working die cavity, such that the inner sleeve ring piece is elastically deformed in a circumferential direction, thereby generating a resisting force against the peak stress in the cylinder. In the flat extrusion cylinder according to the present invention, concentrated internal stress is uniformly transmitted to the inner sleeve ring piece, which decreases the peak stress in dangerous sections and achieves cylinder-type stress distribution in the flat extrusion cylinder. Thus, the stress received by the inner sleeve ring piece is distributed uniformly, thereby increasing the lifespan of the entire flat extrusion cylinder.

Description

[0001]The present application claims benefit of the priority to CN application No. 200910148224.6 titled “AN INNER SLEEVE FOR A FLAT EXTRUSION CYLINDER AND A FLAT EXTRUSION CYLINDER”, filed with the Chinese State Intellectual Property Office on Jun. 18, 2009. The entire disclosures thereof are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to mechanical construction technology, and more specifically to an inner sleeve for a flat extrusion cylinder and a flat extrusion cylinder.BACKGROUND OF THE INVENTION[0003]The flat extrusion cylinder is an indispensable tool for extruding large-sized, flat and wide, thin-wall, complicated hollow and solid profiled material. Since the flat extrusion cylinder usually works in bad conditions such as high temperature, high pressure and high friction, stress distribution is not uniform extremely so that an inner sleeve is prone to rupture, which reduces the working life thereof.[0004]Referring to FIG. 1, FIG...

AI Technical Summary

Benefits of technology

The present invention provides an inner sleeve for a flat extrusion cylinder and a flat extrusion cylinder that can increase lifespan. The inner sleeve includes an inner sleeve ring piece and two insert pieces that match with the inner sleeve ring piece to improve stress distribution. The insert pieces make a minor displacement in upward and downward direction, which generates a resisting force against peak stress in the cylinder. The inner sleeve ring piece is made by forging process and has a regularly distributed metal streamline. The flat extrusion cylinder with the inner sleeve has uniform stress distribution and decreases peak stress in dangerous sections, increasing lifespan of the entire cylinder.

Problems solved by technology

Since the flat extrusion cylinder usually works in bad conditions such as high temperature, high pressure and high friction, stress distribution is not uniform extremely so that an inner sleeve is prone to rupture, which reduces the working life thereof.

Due to the machining and manufacture processes, metal streamline of the dangerous section is not regularly distributed in a circumferential direction, which reduces the utilization effect of material.

Therefore, for such assembled inner sleeve, the lifespan of the intermediate sleeve is decreased, and the space utilization of the flat extrusion cylinder is low.

Taken together, conventional structures of the inner sleeve for the flat extrusion cylinder lead to a shortened lifespan of the flat extrusion cylinder.

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