Metallurgical apparatus – Means treating solid metal
Reexamination Certificate
1999-11-30
2001-06-19
Kastler, Scott (Department: 1742)
Metallurgical apparatus
Means treating solid metal
C219S633000
Reexamination Certificate
active
06248287
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a corrective tempering method and apparatus for correcting the hardening deformation of rolling elements.
In the process of manufacturing rolling elements such as the inner and outer races, cages, and other parts of, e.g., rolling bearings, the deformation of the rolling elements induced by such a heat treatment as hardening has heretofore been corrected by tempering. Conventional tempering methods include so-called “bracing tempering” and press tempering. The former method is characterized as correcting the deformation of a rolling element by subjecting the rolling element to such a normally tempering treatment as keeping the rolling element in the tempering furnace at a required temperature for 60 to 120 minutes with the rolling element being given a reversely bracing deformation using an appropriate tool. On the other hand, the press tempering method is characterized as correcting the deformation of a rolling element by subjecting the rolling element to the aforementioned normally tempering treatment with the rolling element pressured by molds or the like before the tempering treatment.
However, the conventional tempering methods address several problems. One problem is that the treatment time required for correcting the deformation of a rolling element is very long, not only because these methods involve the step of preparing and setting tools, molds, and the like in consideration of the size and amount of deformation of the rolling element to be corrected and pressuring the rolling element with these tools and molds, but also because the rolling element is thereafter subjected to the normally tempering treatment for 60 to 120 minutes in the furnace. More specifically, the following problems have been encountered.
(1) A number of tools and molds must be involved to treat a number of rolling elements on a mass production basis. Therefore, the conventional arts that are of low productivity cannot respond to the needs for mass production.
(2) Further, the tempering furnace, being heated with hot blast, takes 20 minutes or more for heating a rolling element, and there is a limit in shortening the treatment time imposed by this slow heating of the rolling element.
(3) Still further, if atmosphere temperature is increased to shorten the treatment time, the hardness of the rolling element is reduced.
(4) Still further, the heat-treated rolling element still holds inconsistencies caused in turning before the heat treatment, which in turn requires that grinding margins after the heat treatment be increased. As a result, grinding cost reduction is restricted.
SUMMARY OF THE INVENTION
The present invention has been made to overcome conventional problems. Therefore, the object of the invention is to provide a corrective tempering method and apparatus for rolling elements that can correct the heat-treatment deformation of the rolling elements within an extremely short time by utilizing plasticity exhibited during the metallic structure transforming process brought about by low-temperature tempering of the rolling elements that are made of steel.
To achieve the above object, a method according to the invention is achieved by a method of correctively tempering a rolling element of one of a hardened cylindrical element and a hardened annular element, the method including the steps of: inserting the rolling element into a mold to work at least one surface of an inner diameter surface and an outer diameter surface of the rolling element; and heating the rolling element for a heating time within six minutes to a maximum rolling element temperature within 250 to 500° C. to correct a hardening deformation of the rolling element.
Further, an apparatus according to the invention is achieved by an apparatus for correctively tempering a rolling element, which provides: an induction heater heating the rolling element to a desired temperature and including a heating coil; a mold constraining at least one of an inner surface, an outer surface of the rolling element and both of the inner and outer surfaces, the rolling element being at least one of a hardened cylindrical element and a hardened annular element; and a mold temperature adjusting device arranged relative to the heating coil for adjusting a temperature of the mold, the mold temperature adjusting device being positioned outside the heating coil in at least one direction of a radial direction and an axial direction of the heating coil.
REFERENCES:
patent: 1894590 (1933-01-01), Ingersoll
patent: 4479833 (1984-10-01), Gessinger et al.
patent: 5410132 (1995-04-01), Gregg et al.
patent: 5591369 (1997-01-01), Matsen et al.
patent: 56-9217 B2 (1981-02-01), None
patent: 58-35575 B2 (1983-08-01), None
patent: 59-226118 (1984-12-01), None
patent: 62-37315 (1987-02-01), None
patent: 1252363 (1986-08-01), None
Hirakawa Kiyoshi
Maeda Akitoshi
Ohhori Manabu
Sugiyama Hiroaki
Kastler Scott
NSK Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Corrective tempering apparatus for rolling elements does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Corrective tempering apparatus for rolling elements, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Corrective tempering apparatus for rolling elements will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2473211