Hypoid Gear for Super Sports

 The purpose of the hypoid gear provided in the final reduction gears in automobile is to change the direction of drive. With accumulated knowhow on hypoid gears through the development of automobile system hardware, Showa has developed gears for super sport car application. This product, which is to be used for the super sport car transmission system, satisfies required gear tooth property to withstand high torques, four times more than Showa’s conventional type, and high rotation speed. Improved strength was achieved by vacuum carburization or shot peening processes and the mirror fished tooth face was achieved by a special barrel polishing method. Weight reduction was realized by the use of hollow pinion and ring gear with less material.

The Japan's first “mirror-finished gear surface by special barrel polishing

 This product was developed for use in the transmission of a super sport car equipped with high power engine to change the direction of drive by 90 degrees. Unlike ordinary gears, the hypoid gear for super sport car application requires high technologies to achieve: “resistance to high torque / high rotation speed”, “maximum weight reduction”, and “superior quietness.”
 Conventional gears could not “withstand high torque and high rotation speed” because friction heat generated during gear engagement damages the gear tooth face and reduces its durability. To improve this issue, Showa adopted Japan’s first special barrel polishing technology and, with optimal parameters (type of media, mixing ratio, process time, etc.) identified through repeated studies, achieved the mirror finish of the gear tooth that can satisfy required durability. With this technology, we can offer hypoid gears that can withstand high torque (engine output of about 550Nm).

Showa's original high-accuracy gear profile ensures quietness

 “Maximum weight reduction” necessitated the use of a hollow pinion gear and thin ring gear, however, because of the shape and thickness we never experienced before, it was a big challenge for us to find solutions for the warping/deformation of parts caused by vacuum carburization, shot peening and barrel polishing. All manufacturing processes from material to final product were analyzed to identify potential warping/deformation factors and optimal parameters were established for each process. With these efforts, we were able to achieve both weight reduction and strength of the gear.
 “Superior quietness” was a very difficult challenge to overcome because of the big variations of the gear engagement position due to the stiffness of the gear box. Based on our long-nurtured technologies of uniform tooth depth hypoid gears, we tuned the gear tooth shape (i.e., optimization of gear engagement area and length) to minimize the effect of the variations of gear engagement position on gear noise to achieve required quietness.
 These technical knowhow obtained through the development of hypoid gears for super sport cars will be fed forward into future product development.

Hypoid Gear for Super Sports