2014

NTN Corporation (hereafter, NTN) has received the New Product Award for in the New Materials Division at the 2013 Industry Award sponsored by the Japan Powder Metallurgy Association.

Award Name

Japan Powder Metallurgy Association, New Product Award for in the New Materials Division

Awarded Product

Bearphite seal made of sintered metal for variable valve timing device

Product Overview

A bearphite seal used for partitioning the oil chambers within variable valve timing devices. Conventional resin bearphite seals suffer from a lack of dimensional accuracy, which gives rise to problems related to oil leaks during operation, so a sintered metal with much better dimensional precision compared to resin has been used. Development focused on the use of a graphite segregation prevention powder to prevent segregation of the graphite. A Fe-Cu-Sn constituent was also used for low-temperature sintering to reduce dimensional fluctuations and warping. The resulting material has sufficient strength, and has a metallic structure with free graphite distributed around the ferrite base. High precision models are available with different sizes, with dimensional tolerance and seal surface deviation from straightness reduced to approximately 40% of resin seals. The free graphite functions as a solid lubricant and exhibits excellent sliding capabilities. These developments allowed mass-production of sintered metal bearphite seals for variable valve timing devices with high precision and outstanding productivity.

Reason for Receiving the Award

Bearphite seals used in variable valve timing devices were changed from resin to sintered alloy, a fact that was praised highly. In addition, improvements to dimensional accuracy and cost performance were recognized, which led to selection for this award.