Ntn Corporation

Masahiro Nobutomo

Isamu Yoshida

Takayuki Owada

Kiyotake Shibata

Morihisa Yoshioka

Koji Tateishi

Hiromitsu Kondo

Michiyoshi Ishimaru

Hiroshi Yamada

Tokumasa Nakamura

A belt type infinite variable-speed drive using a ball-screw mechanism is compact and noise-free. A nut of the ball-screw mechanism is fixed to a casing and a threaded shaft is rotatably coupled to a movable pulley member through a ball bearing so that ball circulating portions on the nut will not rotate while the movable pulley member is movable axially. Also, the ball circulating portions, which are low in load bearing capacity, are oriented in such a direction that a load hardly acts on the ball-screw mechanism. This makes it possible to compactly and rationally design a belt type infinite variable-speed drive and to suppress noise due to vibration of balls in the ball circulating portions.

Belt type infinite variable-speed drive

An injection unit driving device or an mold-clamping unit driving device having a ball screw having a long life. Of the parts of the ball screw, only the balls are subjected to carburizing/nitriding treatment, while the threaded shaft and the nut are subjected to conventional hardening.

Driving device for injection molding machine

A plurality of balls,are disposed for rolling and circulation in a spiral calculation passage defined between a spiral screw groove surface,formed on the outer periphery of a screw shaft,and a spiral screw groove surface,formed on the inner periphery of a ball nut,. The opposite ends of the ball nut are each formed with a seal mounting portion,, in which a seal member,made of solid lubricating composition is mounted, sealing off the ball nut,. The ball nut,has lubricating grease G sealed therein.

Ball screw with lubricating grease and seal member of solid lubricating composition

A ball screw for a vacuum apparatus which includes a screw shaft having a spiral inner raceway formed on an outer peripheral surface thereof, a ball nut having a spiral outer raceway formed on an inner peripheral surface thereof, a plurality of balls disposed in a spiral space defined between the inner raceway and the outer raceway, and circulating members connecting ends of the spiral space to each other to define a continuous ball circulating passage. The plurality of balls are first balls formed of high polymer material containing polytetrafluoroethylene as a main component and second balls formed of either a metallic material or a ceramic material. The first balls circulate through the circulating passage together with the second balls. The second balls have lubricating films of crystalline polytetrafluoroethylene formed on the surface thereof.

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Shizuoka, Japan

Masahiro Nobutomo