PROBLEM TO BE SOLVED: To provide an air-bubble generating device 10 for a bathtub in which air bubbles generated in bathtub water W are miniaturized, and thereby superior massage effect and fatigue recovery effect can be obtained.SOLUTION: Air bubbles in bathtub water W generated by mixing air with a gas-liquid mixer 14 are made to hit a collision block piece 21 to form fine air bubbles. Further, the fine air bubbles are made to hit a step surface 11s formed in an outlet 11n of a gear pump 11 to perform miniaturization furthermore. In addition to air being mixed from the gas-liquid mixer 14, the air is further mixed with the bathtub water W through an air supply tube along with pressure drop of the bathtub water W generated by an ejector 22. The gear pump 11 is used in the pump, and the air bubbles are miniaturized by gear rotors 11b, 11c of the gear pump 11.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2020,JPO&INPIT【課題】浴槽水Ｗ中に発生させる気泡を微細化し、もって優れたマッサージ効果や、疲労回復効果を得られる浴槽用気泡発生装置１０を提供する。【解決手段】気液混合器１４で空気を混入して発生させた浴槽水Ｗ中の気泡を衝突ブロック片２１に当たって微細気泡にする。さらに、微細気泡を、ギヤポンプ１１の吐出口１１ｎに形成した段差面１１ｓに当てて、より微細化する。気液混合器１４から空気が混入するのに加え、エゼクタ２２によって生じた浴槽水Ｗの圧力低下に伴って、さらに空気を空気供給管を介して浴槽水Ｗに混入させる。ポンプにギヤポンプ１１を使用し、気泡をギヤポンプ１１のギヤロータ１１ｂ、１１ｃによって微細化する。【選択図】図１
