Ntn Corporation

Honda Motor Co., Ltd.

Keisuke Kazuno

Isamu Yoshida

Morihisa Yoshioka

Takaaki Ohnishi

Kensuke Funada

Kunimichi Hatano

Koji Sato

Yoshinori Ikeda

Koji Tateishi

Hiroshi Nakano

Hirakazu Yoshida

Kiyohito Ishikawa

An electric linear actuator has a housing, an electric motor, a speed reduction mechanism and a ball screw mechanism. The ball screw mechanism has a nut and screw shaft. A blind bore is formed on the housing. The blind bore contains an end of the screw shaft. An anti-rotation mechanism for the screw shaft has a sleeve and guide pin. The sleeve is press-formed from steel sheet and fit into the blind bore of the housing. The guide pin is mounted on the end of the screw shaft, via a through aperture formed in the screw shaft. The guide pin axially movably engages the sleeve.

Electric linear actuator

An electric linear actuator has a housing, an electric motor mounted on the housing, a speed reduction mechanism, and a ball screw mechanism. The ball screw mechanism has a nut and screw shaft. Both have helical screw grooves. The screw shaft is inserted into the nut, via a large number of balls. A sleeve is secured on the housing to prevent rotation of the screw shaft relative to the housing. At least one axially extending recessed groove is formed on the inner circumference of the sleeve. At least one guide pin, mounted on the end of the screw shaft, engages the recessed groove. A tapering chamfered portion is formed on the end of the nut.

An electric brake device, in which the rotational drive force of an electric motor () drives a first slave piston and a second slave piston housed in a cylinder body and thereby generates brake fluid pressure, an actuator housing () is coupled to the cylinder body, and the mechanism housing part () and a brake fluid encapsulating part in the cylinder body are partitioned by a sealing member, the actuator housing having a mechanism housing part () for housing an actuator mechanism () for converting the rotational drive force of the electric motor () into the linear drive force for the first slave piston and the second slave piston; wherein the electric brake device is characterized in being provided with an interconnecting hole () for interconnecting the mechanism housing part () and the atmosphere.

Electric brake device

An electrically driven linear actuator with a smooth motion of a ball screw provides an even load distribution as well as a stable motion of the balls and has an electric motor () mounted on a housing (). A nut (or), adapted to mate with the screw shaft (), has a pair of supporting portions () at an axially central position on the outer circumferential surface of the nut (or) to engage one end of a link (). The nut () is formed with a screw groove (). Oval bridge windows () are formed in the nut (or) through a wall with a portion of the screw groove () cut out over a distance of at least two pitches of the screw grooves (). A bridge member (), forming the circulating member, is fitted in each of the bridge windows ().

Electrically driven linear actuator

A ball screw shaft supporting structure of a ball screw rotationally supported by a housing via supporting bearings has a screw shaft formed, on its outer circumference, with a fitting portion and a positioning shoulder. An inner ring of the supporting bearing is press fit onto the fitting portion via a predetermined interference. A steel spacer ring is fit onto the fitting portion from the outer side of the supporting bearing with the inner side of the inner ring abutted against the shoulder. A caulking portion is formed on the end of the fitting portion by plastically deforming the end of the fitting portion radially outward. The inner ring is axially immovably secured on the screw shaft by the caulking portion via, the spacer ring.

Supporting structure of ball screw shaft

A ball screw, which improves its durability under circumstances where a radial load and a moment load are applied to it, has a screw shaft () formed with a helical screw groove () on its outer circumferential surface. A nut () is adapted to mate with the screw shaft (). The nut () is formed with a helical screw groove () on its inner circumferential surface. The nut helical screw groove () corresponds to the screw shaft screw groove (). A number of balls () are rollably contained within a ball rolling passage formed by the oppositely arranged screw grooves (). Bridge members (), each formed with a connecting groove () on its inner circumferential surface, connect the screw grooves () of the nut (). A contact angle (&#x3b1;) between each ball () and one or both the screw grooves () is set within a range of about 20&#x2dc;40&#xb0;.

Ball screw

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 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

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.

Growing community of inventors

Iwata, Japan

Keisuke Kazuno