Mandrel for molding rubber pipes

Abstract

The invention discloses a mandrel for molding rubber pipes. The mandrel is used for molding the rubber pipes and comprises a central portion, a first layer portion and a second layer portion. The central portion is a cylinder; the first layer portion is a column with the cross section in the shape of a circular ring and is extruded and molded on the central portion; the second layer portion is a column with the cross section in the shape of a circular ring and is extruded and molded on the first layer portion. The mandrel has the advantages that the traditional single layer is changed into a double-layer or multilayer structure, accordingly, the quality of the molded mandrel can be greatly improved even on existing molding equipment, namely an extruding machine, the ellipticity of the mandrel can be lowered, and shrinkage marks on the surfaces of the mandrel can be reduced; novel molding production equipment does not need to be purchased, increase of complicated molding working procedures can be omitted, and increase of the production cost can be prevented; the recycling frequencies of the mandrel can be increased, accordingly, the service cost of the mandrel can be lowered, and the service life of the mandrel can be prolonged.

Description

technical field [0001] The invention relates to the technical field of rubber hose molding dies, in particular to a mandrel for rubber hose molding. Background technique [0002] The traditional mandrel for rubber hose molding is mainly formed by one-time extrusion molding on the steel wire rope. The manufacturing process is simple and the process is less. However, when forming some mandrels with larger diameters, due to the larger diameter of the mandrel, after the mandrel is extruded, the wall thickness of the thermoplastic elastomer is thicker during extrusion, which easily leads to the outer diameter of the mandrel. The parameters are unstable due to heat shrinkage, and sink marks appear on the surface of the mandrel, resulting in a large ovality of the mandrel. For example, in practice, when extruding a mandrel with a diameter of 12.45mm, the thickness of one side of the extruded mandrel is 5.305 mm, and the ovality reaches 0.15mm, which cannot meet the needs of the ex...

AI Technical Summary

Problems solved by technology

However, when forming some mandrels with larger diameters, due to the larger diameter of the mandrel, after the mandrel is extruded, the wall thickness of the thermoplastic elastomer is thicker during extrusion, which easily leads to the outer diameter of the mandrel. The parameters are unstable due to heat shrinkage, and sink marks appear on the surface of the mandrel, resulting in a large ovality of the mandrel. For example, in practice, when extruding a mandrel with a diameter of 12.45mm, the thickness of one side of the extruded mandrel is 5.305 mm, and the ovality reaches 0.15mm, which cannot meet the needs of the existing rubber hose production

[0003] And the mandrel is used as the mold for the rubber hose. After vulcanization, the mandrel and the hose are removed by high-pressure water. It is necessary to use very high water pressure to withdraw the mandrel for hundreds of meters from the hose. The mandrel will inevitably be damaged under the action of high-pressure water. Deformation occurs, and the more times you use it, the more obvious the change will be. According to practical experience, the mandrel will have a large ellipse after repeated use for about 5 times.

Therefore, the existing mandrel has a short service life, which increases the production cost

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