Industrial pump and manufacturing method thereof
In an industrial pump, a bearing provided in a pump main body rotatably supports both end sides of a rotating shaft to which an impeller is attached. A shaft seal apparatus is arranged in adjacent to the bearing. The shaft seal apparatus is cooled by a cooling water introduced from an external portion. A shaft seal case is fitted to an inner peripheral surface of a bracket accommodating the shaft seal apparatus in accordance with a shrink fitting. A cooling water is circulated in a boundary portion between the bracket and the shaft seal case. It is omitted a work for closing an opening portion of a cooling means for circulating the cooling water by welding.
1. A manufacturing method of an industrial pump for rotatably supporting both end sides of a rotating shaft to which an impeller is attached by a bearing installed in a pump main body, and cooling a shaft seal apparatus arranged adjacent to said bearing by a cooling water introduced from an external portion, wherein the method comprises the steps of:
forming a cooling chamber or a cooling water flow path in any one of an inner peripheral surface of a bracket to which said shaft seal apparatus is provided, and an outer peripheral surface of said shaft seal case;
forming a concavo-convex surface having an annular concave groove and an annular protrusion having a sharp edge shape in a fitting surface of at least one of said bracket and said shaft seal case;
fitting said shaft seal case to the inner periphery of said bracket by heating said bracket; and
thereafter integrating said bracket and said shaft seal case by cooling said bracket so that the annular protrusion bites into the fitting surface opposed thereto to plastically deform the fitting surface opposed thereto and fasten and integrate said bracket and said shaft seal case;
wherein side edges of said annular protrusion extend perpendicularly to said fitting surface.
2. A manufacturing method of an industrial pump as claimed in claim 1 , wherein the bracket and the shaft seal case are fitted by cooling said shaft seal case at a time of heating said bracket.
3. A manufacturing method as claimed in claim 1 , wherein, during said step of integrating said bracket and said shaft seal case, a fitting surface of any one of said bracket and said shaft seal case is plastically deformed and said annular protrusion bites into an opposing fitting surface.
4. A manufacturing method as claimed in claim 1 , wherein a concavo-convex surface having an annular concave groove and an annular protrusion is provided in a fitting surface of each of said bracket and said shaft seal case.
5. A manufacturing method as claimed in claim 1 , wherein a corner portion of the fitting portion of said bracket to said shaft seal case has a curvature R for avoiding a stress concentration at the corner portion after the shrink fitting.