傘かさ歯は車ぐるま

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Meanings

1

noun

bevel gear

A gear with teeth cut on a conical surface, used to transmit power between intersecting shafts. Technical term in mechanical engineering.

umbrella

歯tooth, cog

平ひら歯は車ぐるま
平歯車 (spur gear) has teeth parallel to the axis, while 傘歯車 (bevel gear) has teeth on a conical surface for intersecting shafts.
はすば歯は車ぐるま
はすば歯車 (helical gear) has angled teeth for smoother operation, but still on a cylindrical surface, unlike the conical 傘歯車.

Compound of 傘 (kasa, 'umbrella') and 歯車 (haguruma, 'gear'), from the umbrella-like conical shape of the gear.