초록 ▼

A metrology apparatus including a body and a first member rotatable relative to the body about a first axis of rotation, said first axis being defined by first bearing and a first motor for actuating rotation of the first member relative to the body about the first axis of rotation. A surface sensin

A metrology apparatus including a body and a first member rotatable relative to the body about a first axis of rotation, said first axis being defined by first bearing and a first motor for actuating rotation of the first member relative to the body about the first axis of rotation. A surface sensing device is attachable to the first member such that the surface sensing device can move with the first member, relative to the body. The first motor may include a first magnet and at least one metal coil spaced apart along the first axis and mounted such that the first magnet and the at least one metal coil are moveable relative to one another.

대표청구항 ▼

1. A metrology apparatus comprising: a body and a member mounted to the body by mechanical bearing assemblies such that the member is rotatable relative to the body about an axis of rotation;a motor for actuating rotation of the member relative to the body about the axis of rotation;wherein a surfac

1. A metrology apparatus comprising: a body and a member mounted to the body by mechanical bearing assemblies such that the member is rotatable relative to the body about an axis of rotation;a motor for actuating rotation of the member relative to the body about the axis of rotation;wherein a surface sensing device is attachable to the member such that the surface sensing device rotates with the rotation of the member, relative to the body;wherein the motor comprises a magnet and at least one metal coil spaced apart along the axis and mounted such that the magnet and the at least one metal coil are moveable relative to one another; andwherein the motor is arranged such that when it actuates rotation of the member relative to the body, substantially no radial forces from the motor act on the mechanical bearing assemblies such that the location of the axis remains substantially fixed. 2. A metrology apparatus according to claim 1, wherein the motor comprises first and second magnets, the second magnet spaced apart from the first magnet along the axis by a spacer and the at least one metal coil is provided between the first magnet and the second magnet. 3. A metrology apparatus according to claim 2, comprising two rings of magnets spaced apart along the axis by the spacer and, between the rings of magnets, a ring of coils suspended such that the magnets and the coils are relatively movable. 4. A metrology apparatus according to claim 3, wherein each ring of magnets comprises alternating north and south poles. 5. A metrology apparatus according to claim 4, wherein north poles of the magnets of one of the rings face and are axially aligned with south poles of magnets of the other ring. 6. A metrology apparatus according to claim 2, wherein the first and second magnets produce a magnetic field across the coil acting predominantly in a direction parallel with the axis. 7. A metrology apparatus according to claim 2, wherein the first magnet and the second magnet are fixed relative to one another to form a magnet assembly and one of the magnet assembly and the at least one metal coil forms the stator of the motor and the other of the magnet assembly and the at least one metal coil forms the rotor of the motor. 8. A metrology apparatus according to claim 1 wherein the motor further comprises magnetisable material, the magnetisable material spaced apart from the magnet along the axis by a spacer and the at least one metal coil is provided between the magnet and the magnetisable material. 9. A metrology apparatus according to claim 8, wherein the magnetisable material is a plate and the magnet and the plate are fixed relative to one another to form a magnet assembly and one of the magnet assembly and the at least one metal coil forms the stator of the motor and the other of the magnet assembly and the at least one metal coil forms the rotor of the motor. 10. A metrology apparatus according to claim 9, wherein the at least one metal coil is fixed to the magnetisable material such that the magnet is moveable relative to the metal coil and the magnetisable material. 11. A metrology apparatus according to claim 1, wherein one of the magnet and at least one metal coil is attached to the member. 12. A metrology apparatus according to claim 1, wherein the motor is a frameless motor. 13. A metrology apparatus according to claim 1, wherein the motor is an ironless-core motor. 14. A metrology apparatus according to claim 1, wherein the axis of rotation is a continuous rotary metrology axis. 15. A metrology apparatus according to claim 1, wherein a position of the motor is servoed. 16. A metrology apparatus according to claim 1, wherein the motor is a direct drive motor. 17. A metrology apparatus according to claim 1, comprising a probe apparatus. 18. A metrology apparatus according to claim 1, further comprising a second member rotatable about a second axis of rotation, said rotation actuated by a second motor. 19. A metrology apparatus according to claim 18 wherein the second axis of rotation is at least one of transverse to the axis of rotation and offset from the axis of rotation. 20. A metrology apparatus according to claim 18, wherein the second motor comprises an ironless core motor. 21. A metrology apparatus according to claim 1, wherein the surface sensing device attachable to the member is a probe. 22. A metrology apparatus according to claim 1, wherein each one of the bearing assemblies comprises a male bearing part that is accommodated in a female bearing part. 23. A metrology apparatus according to claim 1, wherein the member is a spindle and one of the bearing assemblies is provided as each end of the spindle. 24. A metrology apparatus according to claim 1, wherein each one of the bearing assemblies comprises a ball and a support having an aperture for receiving the ball. 25. A metrology apparatus comprising a body and a member mounted to the body by mechanical bearing assemblies that the member is rotatable moveable with respect to the body under the control of a motor, the member attachable to a surface sensing device such that the surface sensing device rotates with a rotation of the member relative to the body, the motor comprising a rotor connected with the member and a stator connected with the body, one of the rotor and the stator comprising a magnetic assembly for establishing a magnetic field that acts on the other of the stator or rotor predominantly in a direction substantially parallel with an axis of rotation of the rotor, and at least one coil on the other one of the stator and rotor, which, when carrying an electric current, generates a magnetic field that cooperates with the magnetic field established by the magnetic assembly to cause rotation of the rotor, the rotor and the stator spaced apart in an axial direction, wherein the pancake motor is arranged such that when it actuates rotation of the member relative to the body, substantially no radial forces from the pancake motor act on the mechanical bearing assemblies such that the location of the axis remains substantially fixed. 26. A metrology apparatus according to claim 25, wherein the magnetic assembly comprises at least one pair of magnets, the magnets of the pair spaced apart in the axial direction, the at least one coil mounted for relative movement between the magnets. 27. A metrology apparatus according to claim 26, wherein the magnet assembly comprises a plurality of pairs of magnets, magnets of each pair spaced apart and aligned in the axial direction, the north pole of one magnet of the pair facing the south pole of the other magnet of the pair. 28. A metrology apparatus according to claim 27, comprising a plurality of coils, each coil, when carrying an electric current, generates a magnetic field through the coil in the axial direction. 29. A metrology apparatus comprising a body and a member movable mounted to the body by mechanical bearing assemblies such that the member is rotatable with respect to the body under control of a pancake motor, the member attachable to a surface sensing device such that the pancake motor provides direct-drive to the surface sensing device for rotating the surface sensing device relative to the body, an axis about which the surface sensing device rotates being defined by the mechanical bearing assemblies, wherein the pancake motor is arranged such that when it actuates rotation of the member relative to the body, substantially no radial forces from the pancake motor act on the mechanical bearing assemblies such that the location of the axis remains substantially fixed. 30. A metrology apparatus comprising: a body and a member mounted to the body by mechanical bearing assemblies such that the member is rotatable relative to the body about an axis of rotation;a motor for actuating rotation of the member relative to the body about the axis of rotation, the motor comprising at least one magnet for generating a magnetic field that acts on at least one coil predominately in an axial direction;wherein a surface sensing device is attachable to the member such that the surface sensing device rotates with the rotation of the member relative to thewherein the motor is arranged such that when it actuates rotation of the member relative to the body, substantially no radial forces from the motor act on the mechanical bearing assemblies such that the location of the axis remains substantially fixed.