Abstract: Provided is a double rotation type scroll expander, aiming at protecting a bearing that supports drive shaft a drive shaft and the like from the heat of a working medium when a working medium introduction hole is provided in the drive shaft. The working medium introduction hole is drilled into the drive shaft such that the high-temperature, high-pressure working medium is supplied to expansion chambers through the working medium introduction hole. An adiabatic sleeve that forms a part of the working medium introduction hole is attached to the drive shaft in an internal region of roller bearings that support the drive shaft and a driven scroll body rotatably. Heat transfer from the working medium to the roller bearings is suppressed by the adiabatic sleeve, whereby the roller bearings are prevented from deteriorating.

Abstract: A seal groove is cut in the distal end face of a wrap of a fixed scroll, with a tip seal being fitted in the seal groove. Swelling members are interposed between both side faces of the tip seal and corresponding opposite side faces of the wrap. Condensed liquid of working medium w and water condensed from steam contained in the working medium w that are present between the tip seal and an end plate provide a sealing effect. When the swelling members swell upon absorbing the condensed liquids, they exert a strong pressing force on the tip seal and the wrap, thereby firmly retaining the tip seal in position. This prevents the tip seal from being pressed against the end plate, so that wear of the tip seal is reduced.

Abstract: A disc-like spacer arranged below a first roller bearing rotatably supporting a driven crankshaft that forms an anti-rotation system is formed with a plurality of notches in the circumferential direction. A spot face is provided to face the outer circumferential surface of the spacer, and communication holes and are drilled on the outer circumferential side of the spot face to extend in the axial direction of the scroll. Also formed is a communication hole communicating the communication hole with the first roller bearing via the notches. A grease nipple is mounted to the communication hole. To replenish grease, the fixed scroll is removed from the housing such that the orbiting scroll is exposed, and grease is injected from the grease nipple into the first roller bearing with a grease gun.