Abstract: Disclosed are an outer race for a constant velocity joint, having improved anti-flaking properties and shaft strength, and a process for producing the same. The outer race for a constant velocity joint includes a cup and a serration and comprises by weight carbon: 0.45 to 0.59%, silicon: 0.15 to 0.4%, manganese: 0.15 to 0.45%, sulfur: 0.005 to 0.15%, molybdenum: 0.1 to 0.35%, boron: 0.0005 to 0.005%, aluminum: 0.015 to 0.05%, and titanium: 0.015 to 0.03%, the proportion of the effective case depth in track grooves of the cup being 0.25 to 0.45 in terms of the ratio of the effective case depth t to the wall thickness of the cup w, t/w, the proportion of the effective case depth of the involute serration in its end being 0.20 to 0.50 in terms of the ratio of the effective case depth t to the radius r, t/r. The involute serration in its end preferably has a former austenite grain size of not less than 8 in terms of the grain size number specified in JIS (Japanese Industrial Standards).

Abstract: Disclosed are a high strength drive shaft and a process for producing the same. The high strength drive shaft comprises as a steel material, by weight, carbon: 0.48 to 0.58%, silicon: 0.01 to 0.15%, manganese: 0.35 to 0.75%, sulfur: 0.005 to 0.15%, molybdenum: 0.1 to 0.35%, boron 0.0005 to 0.005%, aluminum: 0.015 to 0.05%, and titanium: 0.02 to 0.08%, the proportion of the effective case depth of an involute serration in its end of the drive shaft being 0.3 to 0.7 in terms of the ratio of the effective case depth t to the radius r, t/r. The involute serration in its end preferably has a former austenite grain size of not less than 8 in terms of the grain size number specified in JIS (Japanese Industrial Standards). A steel comprising the above constituents and having a hardness of 85 to 95 HRB is machined and form rolled into a shaft, and the shaft is induction hardened and then tempered at 120 to 200° C. to produce the high strength drive shaft.

Abstract: A vehicle having an endless track which is in driving engagement at the front end portion with an engine-driven wheel. A slide rail assembly is provided for engagement with the lower run of the endless track. The suspension mechanism includes a suspension spring assembly which is connected at the front end directly or indirectly with the slide rail assembly. The other end of the spring assembly is connected with the free end of a swingable arm which is pivotably mounted at the other end on the vehicle frame. The intermediate portion of the swingable arm is connected with the rear portion of the slide rail assembly through a linkage including a crank lever.