This invention relates generally to marine propulsion devices, such as outboard motors, and, more particularly, to a drive shaft assembly for use in such a marine propulsion device.
Drive shafts in conventional outboard motors are typically provided with one or more bearing races adjacent their lower ends and are exposed to corrosive water and exhaust gases at their upper ends. To provide improved lower end wear characteristics in conjunction with improved upper end corrosion resistance, prior drive shafts have been manufactured by inertially welding a lower drive shaft member of carbon steel to an upper drive shaft member of stainless steel. However, inertia welding is disadvantageous in that it requires costly secondary operations such as machining, heat treating and straightening.
Attention is directed to the following U.S. Pat. No.:
Zackrisson 4,527,978 July 9, 1985 PA1 Federmann et al. 4,358,284 Nov. 9, 1982 PA1 Loyd et al. 4,272,971 June 16, 1981 PA1 Lakiza et al. 4,127,080 Nov. 28, 1978 PA1 Liaaen 4,112,866 Sept. 12, 1978 PA1 Campbell et al. 3,209,720 Oct. 5, 1965 PA1 Toelke 3,175,374 March 30, 1965 PA1 Shipley et al. 3,138,010 June 23, 1964 PA1 Willis, Jr., et al. 3,083,680 April 2, 1963