Patent ID: 11933407
Assignee: RIKEN
Field: Mechanical elements (Mechanical engineering)
Classification: CPC F | IPC F

Claim 2:
3. The combination of the compression ring, the piston, and the cylinder according to claim 1, wherein
an ovality of the compression ring defined as a difference (d3−d4) and the nominal diameter d1 satisfy a relationship:

−0.013≤(d3−d4)/d1<0

where d3 is a diameter in a first axial direction through the midpoint of the closed gap and d4 is a diameter in a second axial direction orthogonal to the first axial direction when the compression ring is inserted into an annular flexible tape and the flexible tape is drawn to close the compression ring until the closed gap becomes a predetermined gap in a case where the compression ring is attached to the cylinder.