Patent ID: 8836191

Claim:
A power generation apparatus comprising: a thermal engine including an expander comprising a driving unit and a housing comprising a partition wall that defines a housing space that contains the driving unit; and a power transmission shaft that extracts rotational driving force generated by the expander to the exterior of the housing space that contains the driving unit of the expander, wherein the power transmission shaft rotates with a part of a magnetic coupling for transmitting the rotational driving force from the expander to the exterior of the housing space, the magnetic coupling being divided between the interior and exterior of the housing space through a portion of the partition wall, wherein the magnetic coupling includes at least two driving-side magnets that rotate on the inside of the housing space due to the rotational driving force of the expander being transmitted thereto, and at least two slave-side magnets provided outside of the housing space, and at the part of the magnetic coupling with which the power transmission shaft rotates, the at least two slave-side magnets undergoing slave rotation in accordance with the rotation of the driving-side magnets, wherein the driving-side magnets and slave-side magnets are disposed with the portion of the partition wall therebetween and with different magnetic poles facing each other, and the driving-side magnets are disposed so as to surround the outer circumference of the slave-side magnets with a distance provided therebetween, further comprising: a first magnetic path formation member formed of a magnetically permeable material and that magnetically connects the at least two driving-side magnets, and the first magnetic path formation member being disposed so as to make contact with the driving-side magnets on the outer radial side of the magnetic coupling; and a second magnetic path formation member formed of a magnetically permeable material and that magnetically connects the at least two slave-side magnets, the second magnetic path formation member being disposed entirely within a through hole that passes through the part of the magnetic coupling with which the power transmission shaft rotates, and in a radial direction transverse to the rotation axis, so as to make contact with the slave-side magnets.