Compressor

Abstract

A compressor includes an impeller including blades extending along a shroud. Each of the blades includes a leading edge, a trailing edge, and a tip edge connecting the leading edge and the trailing edge and opposing the shroud. The tip edge has a central curve extending along a center of a thickness of the tip edge from the leading edge to the trailing edge. The central curve has a tangential line touching a contact in the central curve. The tangential line has a tip edge inclination angle made by the rotation axis and the tangential line viewed in a reference direction which passes the contact and which is perpendicular to the rotation axis. The tip edge inclination angle increases as the contact approaches a first maximum inclination point in the central curve. The first maximum inclination point is separated from both the leading edge and the trailing edge.

What is claimed is: 
     
         1 . A compressor that compresses a fluid, the compressor comprising:
 a housing in which a shroud is formed;   an impeller provided inside the housing, the impeller being provided so as to be rotatable about a rotating shaft; and   a diffuser provided around the impeller, the diffuser decelerating the fluid discharged from a trailing edge of the impeller in a centrifugal direction,   wherein the impeller includes a conical wheel, and a plurality of blades extending on an outer peripheral surface of the wheel and along the shroud from a leading edge that is an inlet of the fluid towards the trailing edge that is an outlet of the fluid,   wherein in a case in which a central curve of a thickness of a tip edge of each blade, the tip edge opposing the shroud, is projected on a virtual plane including an axis of the rotating shaft, an angle formed, at an intersection point between the central curve projected on the virtual plane and the axis, between a tangential line of the central curve that has been projected and the axis is defined, as a definition, as a tip edge angle, and under the definition, an angular distribution of the tip edge protrudes upwards from the leading edge to the trailing edge, and   wherein a cross section of the trailing edge of the blade has an elliptical arc shape or an arc shape.   
     
     
         2 . The compressor according to  claim 1 ,
 wherein a corner rounded portion that has an arcuate cross section and that smoothly connects a lateral surface of the blade and a hub surface of the wheel is formed at a base of each blade on a trailing edge side, and   wherein a thickness of each blade gradually decreases from a wheel side towards the tip edge.   
     
     
         3 . The compressor according to  claim 1 ,
 wherein in a case in which a central curve of a thickness of each blade on a hub surface side connected to a hub surface is projected on a virtual plane including an axis of the rotating shaft, an angle formed, at an intersection point between the central curve projected on the virtual plane and the axis, between a tangential line of the central curve that has been projected and the axis is defined, as a definition, as a hub surface side angle, and under the definition, an angular distribution on the hub surface side protrudes upwards from the leading edge to the trailing edge,   wherein the angle of the tip edge at the leading edge is smaller than the angle of the leading edge on the hub surface side,   wherein the angle of the tip edge at the trailing edge is substantially equivalent to the angle of the trailing edge on the hub surface side, and   wherein a position where the angle of the tip edge is largest is nearer to the trailing edge than a position where the angle on the hub surface side is largest.   
     
     
         4 . A compressor comprising:
 a housing including an air intake and a compressor impeller chamber opposite to the air intake along a rotation axis, the compressor impeller chamber including a shroud therein;   an impeller provided opposite to the shroud in the compressor impeller chamber to be rotatable around the rotation axis, the impeller comprising:
 a wheel having a substantially conical shape around the rotation axis and provided such that the substantially conical shape tapering toward the air intake; and 
 blades provided on an outer peripheral surface of the substantially conical shape of the wheel and extending along the shroud, each of the blades comprising:
 a leading edge closest to the air intake; 
 a trailing edge farthest from the air intake, a cross section of the trailing edge taken along a reference plane having a substantially elliptical arc shape or a substantially arc shape, the reference plane contacting the trailing edge to be parallel to the outer peripheral surface; 
 a tip edge connecting the leading edge and the trailing edge and opposing the shroud, the tip edge having a central curve extending along a center of a thickness of the tip edge from the leading edge to the trailing edge, the central curve having a tangential line touching a contact in the central curve, the tangential line having a tip edge inclination angle made by the rotation axis and the tangential line viewed in a reference direction which passes the contact and which is perpendicular to the rotation axis, the tip edge inclination angle increasing as the contact approaches a first maximum inclination point in the central curve, the first maximum inclination point being separated from both the leading edge and the trailing edge; 
 
   a diffuser provided around the impeller to decelerate the fluid discharged from the trailing edge of the impeller in a centrifugal direction with respect to the rotation axis.   
     
     
         5 . The compressor according to  claim 4 ,
 wherein each of the blades includes a lateral surface connecting the outer peripheral surface of the wheel and each of the leading edge, the training edge and the tip edge, and   wherein each of the blades includes a corner rounded portion at a base of each of the blades adjacent to the trailing edge, the corner rounded portion having an arcuate cross section taken along an additional reference plane substantially perpendicular to the central curve to smoothly connect the lateral surface of the blade and the outer peripheral surface of the wheel, and   wherein a thickness of each of the blades gradually decreases from the wheel towards the tip edge.   
     
     
         6 . The compressor according to  claim 4 ,
 wherein each of the blades comprises a blade bottom opposite to the tip edge in a radial direction perpendicular to the rotation axis, the blade bottom being defined on the substantially conical shape of the wheel, the blade bottom having a bottom central curve extending along a center of a thickness of the blade bottom from the leading edge to the trailing edge, the bottom central curve having an additional tangential line touching a bottom contact in the bottom central curve, the additional tangential line having a hub surface side angle made by the rotation axis and the additional tangential line viewed in an additional reference direction which passes the bottom contact and which is perpendicular to the rotation axis such that the hub surface side angle increases as the bottom contact approaches a second maximum inclination point in the bottom central curve, the second maximum inclination point being separated from the both the leading edge and the trailing edge,   wherein the tip edge inclination angle at the leading edge is smaller than the hub surface side angle at the leading edge,   wherein the tip edge inclination angle at the trailing edge is substantially equivalent to the hub surface side angle at the trailing edge, and   wherein the first maximum inclination point is nearer to the trailing edge than the second maximum inclination point.