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Itabashi-ku, Japan

Matsuzaki Y.,University of Tokyo | Kadota Y.,University of Tokyo | Uzuka K.,TOK Bearing Co. | Suenaga H.,University of Tokyo | And 2 more authors.
Key Engineering Materials | Year: 2012

This paper proposes a miniaturized non-contact actuation mechanism for a surgical device for bone extension operation. This device is embedded inside the body, and the device controls the gap between the bones cut by the operation. A screw-nut mechanism was used for extension and the screw shaft was turned by a cyloidal reducer. A permanent magnet was attached to the ring gear of this cycloidal reducer, and the force applied to the ring gear magnet was controlled by permanent magnets from outside of the device without direct mechanical contact. The outside magnets were attached at the ends of two bars, which were turned by two stepping motors. Combination of repulsive force and attractive force was selected in a sequence so as to realize the wobbling motion of the ring gear. The dimensions of the device were 7 mm in diameter and 39.7 mm in length. The output thrust was 2.1 N. © (2012) Trans Tech Publications, Switzerland. Source

Miyake M.,Okayama University | Suzumori K.,Okayama University | Uzuka K.,TOK Bearing Co.
Journal of Robotics and Mechatronics | Year: 2012

The purpose of this work is to develop a thin, electromagnetic wobble motor with a large amount of torque, a motor thinner than conventional ones and able to be applied to portable electric equipment. We have developed a basic model of the motor 30 mm in diameter and 5 mm in thickness. In this paper, the basic structure and control method are first presented. Next, the design of the electromagnets and the three types of gear pairs, which have different pressure angles for the reduction mechanism, are presented. Finally, the motor drive experiments are performed using two types of drive: one is a two-phase drive, and the other is a four-phase drive. Three types of gear pairs are also shown. The motor works successfully, and its great potential to be mounted in thin, portable equipments is confirmed. Source

Uchiho T.,University of Tokyo | Uzuka K.,TOK Bearing Co. | Suenaga H.,University of Tokyo | Morita T.,University of Tokyo
Japanese Journal of Applied Physics | Year: 2014

A noncontact detectable force sensor is a promising technique for monitoring the defects of a structural object, such as buildings and bridges, and medical surgery devices. In this study, the noncontact detectable force sensor with an AT-cut quartz crystal resonator and a pair of spiral coils is proposed. The thickness-shear mode is excited with energy trapping excitation. The resonant frequency of this vibration mode is a function of the applied external force because of the nonlinear elastic module. Then, from the resonant frequency change of the quartz crystal, the input force can be measured. Admittance characteristics of this sensor contained series and parallel resonance. We confirmed that noncontact detection of the resonant frequency change is possible by using two facing spiral coils. The coil gap effect could be eliminated by calculating the difference between the series and parallel resonant frequencies. © 2014 The Japan Society of Applied Physics. Source

Kadota Y.,University of Tokyo | Inoue K.,University of Tokyo | Uzuka K.,TOK Bearing Co. | Suenaga H.,University of Tokyo | Morita T.,University of Tokyo
IEEE/ASME Transactions on Mechatronics | Year: 2013

Noncontact operation of a cycloid motor by means of a magnetic force has been realized. The fabricated motor has a cycloid reduction system with an internal gear as a stator and an external gear as a rotor. A cylindrical permanent magnet encloses the internal gear. The internal gear generates a wobbling motion due to attractive and repulsive magnetic forces produced by external permanent magnets. An output shaft attached to an external gear is rotated by the wobbling motion of the internal stator gear. This motor can be operated by means of magnetic fields applied to one side of the device. This feature allows the device to be used in medical procedures such as bone distraction osteogenesis, in which the actuator must be inside the human body for a long period of time. Such noncontact operation of the actuator reduces the burden on the patient. The fabricated motor exhibited a maximum torque of 4.1 mN·m and a maximum linear output of 4.9 N using a screw-nut system when the gap between the outer magnets and the motor was 2 mm. © 1996-2012 IEEE. Source


Tok Bearing Co. | Date: 2003-10-28

(Based on Use in Commerce) Machine parts, namely bearings, rollers, one-way clutches, torque limiters and rotary dampers. (Based on 44(e) Mechanical parts for land vehicles, namely bearings, rollers, one-way clutches, torque limiters, rotary dampers. (Based on Use in Commerce) Parts for non-metal window frames, namely non-metal window pullers; parts for non-metal doors, namely non-metal sliding door wheels and non-metal rollers for sliding doors.

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