Motor-built-in photographic lens

Claim 2

An arrangement for operating a diaphragm device within a lens barrel having an optical axis comprising: a stepping motor including a plurality of ring-shaped field yokes each having pole teeth extending substantially parallel to the optical axis and spaced relative to the teeth of another yoke; a plurality of field coils fixedly mounted on said yokes; a ring-like permanent magnet positioned on the outer periphery of said yoke and rotatable stepwise relative to said yoke of energization of said field coils; said ring-like permanent magnet being made of plastic magnetic material; a diaphragm blade operating member arranged for operating diaphragm blades of the diaphragm device; a drive connection for transmitting stepwise rotation of said ring-like permanent magnet to said diaphragm blade operating member; and said drive connection having a guide groove formed in said ring-like permanent magnet and an arm extending from said operating member, said arm being engageable with said guide groove to integrally connect said permanent magnet and said operating member.

Claim 3

A lens barrel, having a diaphragm unit, comprising: (a) a yoke construction having an aperture through which light passes, said yoke construction being formed in a substantially cylindrical shape and having a magnetic pole region provided at a peripheral surface; (b) a magnetic rotor having an aperture through which light passes, said magnetic rotor being formed in a cylindrical shape with a plastic magnet and being so provided to overlap said yoke construction in a radial direction, wherein a magnetized region of said magnetic rotor is formed with N-poles and S-poles alternatingly positioned at a peripheral surface of said magnetic rotor opposite to said magnetic pole region of said yoke construction; (c) an exciting coil assembled to said yoke construction for receiving a supply of current and causing said yoke construction to generate electromagnetic power for driving said magnetic rotor; (d) said diaphragm unit being drivenly connected to said magnetic rotor; and (e) bearing means having a plurality of bearing balls for rotatably supporting said magnetic rotor, said bearing balls being supported by a receiving groove directly molded in a peripheral surface of said magnetic rotor and in a peripheral direction, wherein said receiving groove is formed at the peripheral surface of said magnetic rotor opposite to said yoke construction and at such a position as deviating in a radial direction from said magnetic pole region of said yoke construction.

Claim 4

A lens barrel, having a diaphragm unit, comprising: (a) a yoke construction having an aperture through which light passes, said yoke construction being formed in a substantially cylindrical shape and having a magnetic pole region provided at a peripheral surface; (b) a magnetic rotor having an aperture through which light passes, said magnetic rotor being formed in a cylindrical shape with a plastic magnet and being so provided to overlap said yoke construction in a radial direction, wherein a magnetized region of said magnetic rotor is formed with N-poles and S-poles alternatingly positioned at a peripheral surface of said magnetic rotor opposite to said magnetic pole region of said yoke construction; (c) an exciting coil assembled to said yoke construction for receiving a supply of current and causing said yoke construction to generate electromagnetic power for driving said magnetic rotor; (d) said diaphragm unit being drivenly connected to said magnetic rotor; and (e) bearing means having a plurality of bearing balls for rotatably supporting said magnetic rotor, said bearing balls being supported by a receiving groove directly molded in a peripheral surface of said magnetic rotor and in a peripheral direction, wherein said receiving groove is formed at the peripheral surface of said magnetic rotor opposite to said yoke construction and at such a position as deviating in a radial direction from said magnetic pole region of said yoke construction.

Claim 5

A lens mounting according to claim 2, wherein said magnetic rotor further comprises a groove formed directly therein by molding for connection with said diaphragm unit, said groove being formed in a radial direction of said magnetic rotor.

Claim 6

A lens barrel which comprises a yoke construction having an aperture through which light passes, a magnetic rotor having an aperture through which light passes, and an exciting coil being assembled to said yoke construction for receiving a supply of current and causing said yoke construction to generate electromagnetic power for driving said magnetic rotor, and for driving a diaphragm unit built therein in response to a rotation of said magnetic rotor, wherein: (a) said diaphragm unit at least includes: (a-1) a plurality of diaphragm blades each having first and second pivot pins mounted at deviated positions on opposing planes thereof; (a-2) a fixed member for supporting each of said first pivot pins at one of said opposing planes of said plurality of diaphragm blades and enabling said diaphragm blades to swing about said first pivot pins, said fixed member having an aperture through which light passes; and (b) said magnetic rotor being formed by molding with a plastic magnet and having a groove which is formed simultaneously by said molding, said magnetic rotor having each of said second pivot pins at the other of said opposing planes of said plurality of diaphragm blades inserted therein, wherein said plurality of diaphragm blades swing in response to a rotation of said magnetic rotor for varying a diaphragm aperture formed by said diaphragm blades.

Claim 7

A lens barrel which comprises a yoke construction having an aperture through which light passes, a magnetic rotor having an aperture through which light passes, and an exciting coil being assembled to said yoke construction for receiving a supply of current and causing said yoke construction to generate electromagnetic power for driving said magnetic rotor, and for driving a diaphragm unit built therein in response to a rotation of said magnetic rotor, wherein: (a) said diaphragm unit at least includes: (a-1) a plurality of diaphragm blades each having first and second pivot pins mounted at deviated positions on opposing planes thereof; (a-2) a fixed member for supporting each of said first pivot pins at one of said opposing planes of said plurality of diaphragm blades and enabling said diaphragm blades to swing about said first pivot pins, said fixed member having an aperture through which light passes; and (b) said magnetic rotor being formed by molding with a plastic magnet and having a groove which is formed simultaneously by said molding, said magnetic rotor having each of said second pivot pins at the other of said opposing planes of said plurality of diaphragm blades inserted therein, wherein said plurality of diaphragm blades swing in response to a rotation of said magnetic rotor for varying a diaphragm aperture formed by said diaphragm blades.