To solve problems that inaccuracy occurs in the evenness of the sliding gap between a cylinder and a piston, partial abrasion occurs on the sliding surface, or the sliding gap is lost, and as a result, the rotational movement of the piston is impaired and the function of the compression mechanism may fail, because, when an intake connection pipe and an intake outer pipe are brazed, the stress is generated from the difference in the dimension of contraction caused by the difference of the thermal expansion coefficient and the cylinder is deformed by the action of the stress.

A material softer than the intake connection pipe body is inserted between the brazed part to the intake outer pipe and a part to be forced into the cylinder, and the stress generated from the difference of the thermal expansion coefficient as a result of the deformation and displacement is absorbed by the material.