hypoid gear

...Also, as you go from the inner end to the outer end of a bevel gear, there are those whose tooth height does not change and those whose tooth height does change; the former are called equal-height teeth and the latter are called gradient teeth. (4) Hypoid gear A gear used to transmit power between two non-intersecting, misaligned shafts (usually at a 90° shaft angle), and has a shape similar to a bevel gear (Figure 6-h). Compared to normal spiral bevel gears, it has the advantages of being able to be attached more firmly, the shaft diameter can be made larger by increasing the helix angle of the pinion, increasing strength, a higher reduction ratio than a bevel gear, and lower noise levels.

*Some of the terminology that mentions "hypoid gear" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…また，かさ歯車の内端部から外端部へいくに従って，歯の高さが変わらないものと変わるものとがあり，前者を等高歯，後者をこう配歯という。(4)ハイポイドギヤhypoid gear　交差せずに，食い違っている2軸(ふつう軸角90゜)の間の伝動に用いられる歯車で，かさ歯車に似た形状をもつ(図6‐h)。ふつうの曲がりばかさ歯車に比べて，取付けが強固にできること，小歯車のねじれ角を大きくすることにより軸の径を大きくすることが可能で強度を増大できること，減速比がかさ歯車より高くとれること，騒音が低いなどの利点がある。…

※「hypoid gear」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報