Patent ID: 6928922

Claim:
A lubricating structure for a hydraulic driving apparatus comprising a body supporting a drive shaft, wherein said drive shaft is driven rectilinearly or rotationally by an operation oil supplied to said body, and further comprising a liquid tightness-retaining section providing a sealing function between said drive shaft and said body, said liquid tightness-retaining section comprising: an oil supply port which is openable to an exterior of said body; a groove communicating with said oil supply port via a passage, said groove being formed annularly along an inner circumferential surface of a support portion of said body for supporting said drive shaft in said body; and an oil-retaining member installed in said groove, said oil-retaining member being composed of a resin material, wherein a lubricant, which is supplied from said oil supply port, permeates into and is supported within said oil-retaining member, said lubricant further being supplied to a clearance formed between an outer circumferential surface of said drive shaft and said inner circumferential surface of said body, and wherein said lubricant has characteristics different from those of said operation oil.