Concentricity measuring apparatus and method, squareness measuring apparatus and method, and concentricity-squareness measuring apparatus and method

A method for measuring concentricity of two holes in a cylindrical member, the cylindrical member having the two holes at both ends and a partition wall between the two holes, comprising:

• supporting the cylindrical member and rotating the cylindrical member about one of the two holes;
• and measuring the concentricity of a longitudinal center line of the other hole to a longitudinal center line of the one hole, by measuring a relative position of the inner circumferential surface of the other hole to the longitudinal center line of the one hole over the whole inner circumferential surface of the other hole, while the cylindrical member is rotated by a rotation unit.

A squareness measuring apparatus for measuring squareness of at least one end surface of a partition wall between two holes in a cylindrical member to a longitudinal center line of at least one of the two holes, the cylindrical member having the two holes at both ends and the partition wall between the two holes, comprising:

• a rotation unit configured to rotate the cylindrical member about the one hole;
• and a squareness measuring unit configured to measure the squareness of the at least one end surface of the partition wall to the longitudinal center line of the other hole in the other hole, by measuring a relative position of the at least one end surface of the partition wall along the longitudinal center line of the other hole in the other hole over the whole circumference of the at least one end surface of the partition wall, while the cylindrical member is rotated by the rotation unit.

A method for measuring squareness of at least one end surface of a partition wall between two holes in a cylindrical member to a longitudinal center line of at least one of the two holes, the cylindrical member having the two holes at both ends and the partition wall between the two holes, comprising:

• supporting the cylindrical member and rotating the cylindrical member about the one hole;
• and measuring the squareness of the at least one end surface of the partition wall in the other hole to the longitudinal center line of the other hole, by measuring a relative position of the at least one end surface of the partition wall in the other hole along the longitudinal center line of the other hole over the whole circumference of the at least one end surface of the partition wall, while the cylindrical member is rotated by a rotation unit.

A method for measuring concentricity of two holes in a cylindrical member, the cylindrical member having the two holes at both ends and a partition wall between the two holes, and for measuring squareness of at least one end surface of the partition wall to a longitudinal center line of at least one of the two holes, comprising:

• supporting the cylindrical member and rotating the cylindrical member about one of the two holes;
• measuring the concentricity of a longitudinal center line of the other hole of the cylindrical member to a longitudinal center line of the one hole, by measuring a relative position of an inner circumferential surface of the other hole to the longitudinal center line of the one hole over the whole inner circumferential surface of the other hole, while the cylindrical member is rotated by the rotation unit;
• and measuring the squareness of the at least one end surface of the partition wall to the longitudinal center line of the other hole in the other hole, by measuring a relative position of the at least one end surface of the partition wall along the longitudinal center line of the other hole in the other hole over the whole circumference of the at least one end surface of the partition wall, while the cylindrical member is rotated by the rotation unit.