Patent ID: 7921565

Claim:
A working fluid injection apparatus comprising: an upper chamber that stores a working fluid; a lower chamber for removably receiving a bearing unit having a housing and a shaft that is inserted in the housing to form, between the shaft and the housing, a gap into which the working fluid is to be injected; a partition that divides the upper chamber and the lower chamber into top and bottom parts, respectively; a first exhaust system that brings the inside of the upper chamber to a decompressed state; a second exhaust system that brings the inside of the lower chamber to a decompressed state; a valve unit that opens and closes an internal cavity of the lower chamber relative to an external environment; a tapered hole formed in the partition and communicating the upper and lower chambers to one another; a tapered shaft inserted into the tapered hole from the upper chamber; and a shaft drive unit that moves the tapered shaft in the axial direction in the tapered hole.