Rotary unit of supercharger for engine and balance adjustment method thereof
View Patent ↗A rotary unit is rotatably accommodated within a supercharger casing of a supercharger for pressurizing an intake air of an engine. The rotary unit includes a supercharger rotary shaft, an impeller fixed to a tip end portion of the supercharger rotary shaft, a rotating component rotatable together with the supercharger rotary shaft independently of the impeller, and a nut member for pressing the impeller and the rotating component in a direction axially of the supercharger rotary shaft to thereby fix them to the supercharger rotary shaft. The nut member is formed with an adjustment portion for the rotational balance adjustment.
1. A balance adjusting method for a rotary shaft of a centrifugal flow supercharger to pressurize an intake air for an engine, which method is to adjust the balance of the rotary shaft of the supercharger prior to assemblage of the supercharger, the method comprising:
a rotary unit assembling step of mounting to the rotary shaft an impeller, to be fixed to a tip end of the rotary shaft, and a rotation member, which is separate from the impeller and capable of rotating integrally with the rotary shaft, and then axially pressing the impeller and the rotation member with the use of a fixing member to fix to the rotary shaft, thereby to assemble a rotary unit having a bearing housing in the rotary unit to accommodate therein a bearing to support the rotary shaft;
a rotational balance adjusting step of adjusting the rotational balance of the rotary unit by forming an adjustment portion in the rotation member or the fixing member to allow an adjustment on the adjustment portion;
an assembling step of incorporating the rotary unit, after the rotational balance has been adjusted, in a casing of the supercharger without being dismantled; and
during the rotational balance adjusting step, the rotary unit is rotated, while fixedly supporting the bearing housing, to adjust the rotational balance of the rotary unit.
2. An assembling method for the centrifugal supercharger including a rotary shaft, which has been adjusted by the balance adjusting method as claimed in claim 1 , comprising providing a non-rotating component in the rotary unit that does not rotate together with the rotary shaft, and
inserting a shim in between the non-rotating component and the casing to adjust a tip clearance between the impeller and the casing.