Ntn Corporation

Ntn Toyo Bearing Co., Ltd.

Isamu Yoshida

Morihisa Yoshioka

Yoshinori Ikeda

Keisuke Kazuno

Koji Tateishi

Masahiro Nobutomo

Kiyotake Shibata

Kei Kimata

Yoshinobu Yasuda

Takayuki Owada

Masahiro Saruta

Koji Sato

Kiyoshige Yamauchi

Masaaki Toda

A ball screw in a continuously variable speed transmission has an axially immovable pulley half () and axially movable pulley half () both mounted on a rotary shaft (). The axially movable pulley half () is moved by a ball screw () so as to infinitely vary the belt wrapping radius and thus the transmission speed. A nut (), forming one part of the ball screw (), is immovably secured in both axial and rotational directions. A screw shaft (), forming the other part of the ball screw (), is movable in both axial and rotational directions. The screw shaftis connected to the axially movable pulley half (). The axially movable pulley half () is axially moved by rotating the screw shaft ().

Ball bearing and a continuously variable speed transmission of belt type

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

A ball screw mechanism comprises a screw shaft, a nut and balls. The nut has a cylindrical portion in the axial middle on the outer peripheral surface thereof that becomes a fitting surface for fitting in a sleeve, and small diameter step portions in the opposite axial sides on the outer peripheral surface thereof that become non-fitting surfaces not fitting in the sleeve. A portion of a wheel steering shaft is provided with the screw shaft, and a plurality of balls are disposed in a rolling way defined between a thread groove formed in the outer periphery of the screw shaft and a thread groove formed in the inner periphery of the nut.

Ball screw and wheel steering device having the same

A portion of a steering shaft capable of being advanced and retracted defines a ball screw shaft of a ball screw mechanism A motor rotor of an electrically driven motor for providing a steering assist force is externally mounted on a rotary nut Mounting of the motor rotor onto the rotary nut is carried out so that the both can be adjustably aligned. By way of example, the rotary nut has an outer peripheral surface formed with an annular protrusion of a arcuate longitudinal sectional shape, having a surface thereof formed with a plurality of axially extending surface indentations arranged side by side in a direction circumferentially of the rotary nut

Powered steering device and ball screw mechanism therefor

To provide a wheel steering apparatus capable of exhibiting a stabilized vehicle steerability without transmitting an external disturbance torque to a motor rotor even when the wheel receives an axially acting external force, this wheel steering apparatus includes a reciprocatingly movable rod drivingly connected with a support member for steerably supporting a wheel and a ball screw mechanism for reciprocatingly moving the rod in response to rotation of a drive motor In a rotational transmission system for transmitting rotation of the drive motor to a nut member of the ball screw mechanism a clutch assembly defining a reverse input limiting means is provided for preventing a rotar of the drive motor from being rotated by the external force acting on the wheel This clutch assembly used is of a design wherein although rotation can be transmitted from an input shaft to an output shaft, no rotation is transmitted from the output shaft to the input shaft.

Wheel steering apparatus

An electrically powered steering device comprises a ball screw mechanism for transmitting a steering force from a steering wheel to steerable vehicle wheels. The ball screw mechanism includes a rotary nut having a nut body in which a circulating passage is formed so as to extend axially thereof, and end caps and secured respectively to opposite ends of the nut body . Each of the end caps and has defined therein respective guideways and for balls that communicate opposite ends of the circulating tunnel with a ball rolling passage . The end caps and and the nut body are made of a sintered alloy. The nut body has an outer periphery of one end thereof that is axially progressively reduced in diameter to define a tapered surface.

Electrically powered steering device

A ball screw ( ) includes a bridge member ( ) fitted to a rotary nut ( ) and provided with a plurality of connecting grooves ( ). Each connecting groove ( ) connects neighboring convolutions of an inner spiral groove ( ) of the rotary nut ( ). The ball screw ( ) is used as a mechanism for transmitting rotation of a rotor ( ) of a motor ( ) to a steering shaft ( )in an electrically powered steering device.

Ball screw and electrically powered steering device having the ball screw

A ball screw mechanism ( ) compact in size, employing a minimized number of component parts and having a high load capacity includes a rotary nut ( ) having an internally threaded helical groove ( ) and a mounting hole ( ) both defined therein, and a simplified bridge member ( ) mounted in the rotary nut ( ). The bridge member ( ) has a plurality of connecting grooves ( ) defined on an inner surface thereof each operable to communicate neighboring convolutions of the internally threaded helical groove ( ). The bridge member ( ) has its opposite side edges formed with respective guide walls ( ) protruding in a direction radially outwardly of the rotary nut ( ) that are crimped to allow the bridge member ( ) to be fixedly retained within the mounting hole ( ).

Ball screw mechanism and electrically powered steering device utilizing the same

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 fuel flow rate measuring device comprising a control rod axially movable in proportion to the rate of flow of air flowing through a suction pipe, a ball disposed in a taper bore and adapted to be moved in the taper bore by the control rod, the taper bore and the ball cooperating with each other to define a clearance which is variable in proportion to the rate of flow of the air, and a pressure regulator provided between a fluid inlet and outlet for keeping constant the fluid pressure difference across the clearance defined by the taper bore and ball.

Growing community of inventors

Iwata, Japan

Isamu Yoshida