Chuetsu Metal Works Co., Ltd.

Oiles Corporation

Atsushi Yasukawa

Kunio Nakashima

Wataru Yago

Kenichi Ichida

Takashi Nakamaru

Masao Hosoda

Ryouichi Ishigane

Shigeyuki Aburatani

Sumiko Sanuki

Kunihiro Uraki

Satoshi Takamura

Kazuo Takeuchi

A synchronizer ringhas an annular ring body; a friction materialjoined integrally to a cylindrical inner peripheral surfaceof the ring body; a conical surfaceformed on an inner surface of the friction material; and a plurality of annular groovesformed in the conical surfaceof the friction material

Synchronizer ring

A lead-containing copper-based alloy is immersed into a weak acidic or neutral etching solution having a buffer effect which is formed by adding an organic acid into a complexing agent having a high ability to form a complexing ion with lead, and lead particles present on the surface of the lead-containing copper-based alloy are then removed. The complexing agent is one of an organic ammonium salt such as ammonium acetate, or ammonium citrate, or may be an organic sodium salt such as sodium acetate, sodium tartrate, and sodium citrate. Preferably, an immersion temperature of the alloy to the etching solution falls within a range of from 10 to 50&#xb0; C. The etching solution is agitated with oxygen or a gas containing oxygen blown thereinto during the immersion of the alloy into the etching solution. An extremely low voltage of &#x2212;0.3 to +0.2 V vs. NHE is applied from outside to the lead-containing copper-based alloy as an anode.

Method for preventing lead from dissolving from a lead-containing copper-based alloy

In a synchronizer ring that is a part of an automobile transmission, a ring body is made of an iron material and a sliding member is made of a wear-resistant copper alloy having the following chemical components, matrix and rigidity, characterized in that the ring body and sliding member are bonded to each other by way of hot working. (1) a wear-resistant copper alloy containing Zn of 22 to 45 wt %, at least one kind of metal elements of 0.1 to 15 wt % which are selected from a metal element group of Al, Mn, Fe, Pb, Ni, Be, Si, Co, Cr, Ti, Nb, V, Zr, Mo, Sn, Bi, B etc. and the remnant composed of Cu and impurities. (2) The wear-resistant copper alloy has a matrix of .alpha. phase+.beta. phase, .beta. phase alone or .beta. phase+.gamma. phase. (3) HRB (Hardness Rockwell B) value is more than 80. As a result, it is possible to provide a high performance composite-material synchronizer ring capable of sufficiently withstanding a high load since it comprises a ring body made of an iron material which is superior in rigidity and strength and a wear-resistant copper alloy material bonded to the sliding surface side of the ring body by way of hot working such as hot forging and the like.

Method of connecting a sliding member to a synchronizer ring

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Tateyama-machi, Japan

Atsushi Yasukawa