Scroll expander with exhaust path thru bearings and a partition plate

A scroll expander used in a Rankine cycle in which a working fluid circulates, comprising:

• a housing formed of a front housing and a rear housing;
• a drive shaft a base end of which is housed in the housing and a tip end of which projects out of the housing;
• a fixed scroll fixed to a side closer to the base end of the drive shaft rather than to the tip end of the drive shaft inside the housing;
• an orbiting scroll arranged on a side of the fixed scroll closer to the tip end of the drive shaft in a rotatable structure inside the housing;
• a bearing arranged on a side of the orbiting scroll closer to the tip end of the drive shaft inside the housing and configured to support the drive shaft in a rotatable structure with respect to the housing via a plurality of rolling elements;
• and
• a sealing member arranged on a side of the bearing closer to the tip end of the drive shaft inside the housing and configured to surround an outer peripheral surface of the drive shaft, wherein
• the fixed scroll has a fixed-side scroll portion formed in a spiral shape when viewed from an axial direction of the drive shaft,
• the orbiting scroll has an orbiting-side scroll portion formed in a spiral shape when viewed from the axial direction of the drive shaft and meshing with the fixed-side scroll portion,
• the housing includes a suction port formed at a position on an opposite side to the drive shaft with the fixed scroll interposed between the suction port and the drive shaft and configured to introduce high-pressure working fluid from an external circuit, a discharge port formed on a side of the bearing closer to the tip end of the drive shaft and configured to discharge low-pressure working fluid to an external circuit, a low pressure chamber formed on an outer side of the orbiting-side scroll portion when viewed from an axial direction of the drive shaft, and a tip end-side low-pressure space being a space in which the sealing member is arranged,
• the front housing is provided with a partition wall configured to partition the tip end-side low-pressure space and the low pressure chamber from each other, the partition wall being disposed at a position located between the tip end-side low-pressure space and the low pressure chamber when viewed from a radial direction of the drive shaft and located closer to the discharge port than the drive shaft when viewed from the axial direction of the drive shaft,
• a communication space configured to communicate the tip end-side low-pressure space with the low pressure chamber is disposed at a position located between the tip end-side low-pressure space and the low pressure chamber when viewed from a radial direction of the drive shaft and opposed to the discharge port with a center of the drive shaft interposed between the position and the discharge port when viewed from the axial direction of the drive shaft;
• and
• when the low-pressure working fluid that has moved from the communication space to the tip end-side low-pressure space flows to the discharge port, the low-pressure working fluid actively flows around the sealing member exposed in the tip end-side low-pressure space to actively cool the sealing member.