Timken : Patent Issued for Unified Rolling and Bending Process for Roller Bearing Cages

Photo of bearings

The Timken Company (North Canton, OH) has been issued patent number 9021706, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent’s inventors are He, Ming (North Canton, OH); Simmons, Michael D. (Canton, OH).

This patent was filed on January 28, 2011 and was published online onMay 5, 2015.

From the background information supplied by the inventors, news correspondents obtained the following quote: “The present disclosure is related generally to methods for manufacturing large diameter tapered roller bearing cages, and in particular, to a method of manufacture for such tapered roller bearing cages which utilizes straight steel strip or plate material.

“Manufacture of large tapered roller bearing cages, which are typically greater than 500 mm in diameter, is challenging work due to the fact that these bearing cages must meet high technical standards, are usually produced in low quantity, require large sized tools, and may be subject to frequent design changes. Currently, large tapered roller bearing cages are produced by spinning or ring rolling/machining processes. Spinning is a cost intensive process requiring part-specific giant mandrels and tailstocks. With increasing cage size, spinning becomes a prohibitive process due to the difficulty of locating a large enough blank for a mandrel to meet the required cage size. The cost of large sized steel plates is also increased exponentially. Similarly, ring rolling and machining processes for large cages are also very expensive.

“Accordingly, it would be advantageous to eliminate the use of the part-specific mandrels and tailstocks to significantly reduce the manufacturing costs of large diameter tapered roller bearing cages, especially when the numbers of cage types are large and the annual quantity for each type of cage is small. It would be further advantageous to utilize only straight metal strips, coils, or plates as raw materials in the manufacturing process, thereby reducing material supply problems even when the cage size is large and achieving the maximum material utilization.

“Conventional methods for the manufacture of large diameter tapered roller bearing cages, such as spinning or ring rolling/machining processes are limited to working with materials having a maximum thickness, constrained by material formability and the tool load-carrying capacity of the forming process. Accordingly, it would be further advantageous to provide a method of manufacture which is not limited to a maximum thickness of a cage that can be formed.

“Finally, it would be beneficial to provide a manufacturing process for large diameter tapered roller bearing cages which is highly flexible for quick part change-over and size adjustment, and which can achieve superior dimensional and geometric precision when utilized with advanced gauge control, feedback and numerical control systems.”

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors’ summary information for this patent: “Briefly stated, the present disclosure provides a method for manufacturing tapered roller bearing cages, including large diameter tapered roller bearing cages, utilizing straight metal strips, coils, or plates as a raw material. The method begins by feeding a straight metal strip, coil, or plate (cage blank, hereinafter), precisely dimensioned in width, length and thickness, with or without windows or pockets pre-cut, into a rolling mill. The rolling mill incorporates a pair of unparallel forming rolls disposed such that a gap between the rolls is in a wedge configuration. As the cage blank is fed through the wedge-shaped forming roll gap, one side of the cage blank is plastically deformed to reduce its thickness and to elongate its length, while no deformation, or only a very slight deformation, is introduced to the other side of the cage blank. This introduces a linear and uniform reduction of the thickness from zero at one lateral edge to a predetermined amount at the other lateral edge. Thus the originally straight cage blank is formed into an arc shape. A third roll disposed on the exit side of the forming rolls, in a pre-calculated position, bends the rolled cage blank into a circular conical ring. After the entire cage blank is rolled into the conical ring, the conical ring may pass through the rolling mill one more time for a final resizing. The butt ends of the formed conical ring are joined together after any necessary trimming of the portions with inaccurate dimensional and geometric configurations, to form a completed large diameter tapered roller bearing cage.

“In an alternate embodiment, a fourth roll is disposed at the entry side of the rolling mill to address a tail section of a formed cage blank having a portion that is flat or has less curvature because of the distance between the forming rolls and the third roll. The fourth roll rises to a pre-determined height to bend the tail of the cage blank to a required curvature before the tail of the cage blank enters the rolling mill.

“The foregoing features, and advantages set forth in the present disclosure as well as presently preferred embodiments will become more apparent from the reading of the following description in connection with the accompanying drawings.”

For the URL and additional information on this patent, see: He, Ming; Simmons, Michael D.. Unified Rolling and Bending Process for Roller Bearing Cages. U.S. Patent Number 9021706, filed January 28, 2011, and published online on May 5, 2015.