Lubricant for thread rolling and thread rolling method

Abstract

A thread rolling lubricant of a nonchlorine species, in which a lubricant base oil is blended with 25 through 35 weight % of (A) a sulfur species extreme pressure agent, 6 through 16 weight % of (B) an organic zinc compound, 2 through 12 weight % of (C) a calcium species additive, and 2 through 13 weight % of (D) an oiliness agent for carrying out thread rolling.

Description

[0001]This application claims priority to Japanese patent application serial number 2007-324549, the contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a lubricant blended preferably for thread rolling and a thread rolling method using the same.[0004]2. Description of Related Art[0005]A screw thread can be formed by machining on a comparatively large-sized metal material of an insert nut arranged at, for example, an oil filter of an automobile or the like. However, in machining, a cutting chip is produced, and a step of removing the chip is complicated. In contrast thereto, in a case of thread rolling, a fabrication cost is low in comparison with that of machining and also the cutting chip is not produced. A strength of a rolled thread is higher than that of a cut screw. Therefore, a member forming a screw thread by machining is desired to shift to thread rolling.[0006]When a metal m...

AI Technical Summary

Benefits of technology

The invention is a lubricant for thread rolling that is nonchlorine and environmentally friendly. It includes a sulfur extreme pressure agent, an organic zinc compound, a calcium additive, and an oiliness agent. The rates of blending of the additives can be adjusted based on the desired performance and cost. The lubricant provides excellent lubricity even at high thread rolling speeds, reducing the width dimension of the recess of the screw thread top portion and promoting a high-quality product. The efficiency of reducing material costs is high, with a minimum amount of blending required for the calcium additive.

Problems solved by technology

However, in machining, a cutting chip is produced, and a step of removing the chip is complicated.

However, when the chlorine species lubricant is used, a chlorine species additive component is decomposed in working or ageing which can rust a material or a tool.

Also, in incinerating, a harmful substance of dioxin or the like is generated, which is adverse to an environment.

Further, an incinerator is corroded or damaged to shorten a service life thereof.

Furthermore, when a debris by chipping off the top portion 2 in fastening is bit by a fitting portion of the screw (between a flank of the male screw and a flank 4 of the female screw), the following problem is posed.

Further, a removing operation by a seizure is difficult.

However, when the recess 3 of the top portion 2 is large, there is also a danger of bringing about an error in the flank angle or a height dimension of the screw thread.

Therefore, as in the four references, a lubricant is not suitable for thread rolling since the lubricant is excellent simply in the lubricity.

Because when the lubricant is simply excellent in the lubricity, the folding operation becomes rather difficult to be produced, and also the recess of the screw thread portion tends to be enlarged.

Although when the lubricity of the lubricant is reduced, the recess of the screw thread portion can be reduced, thereby, a goal of surface roughness or shape of the screw thread is failed, and therefore, a quality of a product is deteriorated.

However, even when the productivity is intended to increase, the revolution number cannot simply be increased.

Because with an increase in the revolution number, a work material and a rolling tool are exposed to more severe working condition.

Further, also a size of a recess of a screw thread top portion is not particularly investigated.

Therefore, a problem remains in the lubricant of the background art for working a screw thread also in this respect.

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