Harmonic Drive Systems Inc.

Harmonic Drive Aktiengesellschaft

Yoshihiro Tanioka

Masaru Kobayashi

Norio Shirokoshi

Kiyoto Kobayashi

Hiroshi Kameda

Harushige Aoyagi

Hiroshi Nakagawa

An actuator has a motor and a wave gear reduction drive in which a wave generator is coaxially connected to an output shaft protruding forward from a front surface thereof. A shaft portion of the output shaft coaxially extends through inside a cylindrical trunk in the flexible internal gear of the wave gear reduction drive, and a magnetic encoder for detecting the rotation of the output shaft is mounted on the shaft portion. Since the dead space inside the cylindrical trunk is used as the space for disposing the magnetic encoder, an entire length can be reduced in comparison with an actuator in which the motor, the wave gear reduction drive, and the encoder are arranged in the axial direction.

Actuator having wave gear reduction drive

A rigid internal gearof the wave gear device is composed by integrating a tooth-forming ringformed with internal teeth, and a main gear ringinto a single body. The tooth-forming ringis manufactured from a ferrous or copper material that has superior strength and abrasion resistance, while the main gear ringis manufactured from a lightweight material, such as an aluminum alloy. The outer circumferential surface of the tooth-forming ringis aluminized to form a dispersed aluminum coatingbefore the tooth-forming ringis cast within the main gear ringso as to integrate the main gear ringand the tooth-forming ringBoth parts are reliably integrated so that a large amount of torque can be transmitted, whereby realizing a rigid internal gear that is lighter than conventional models.

Method of manufacturing a rigid internal gear of a wave gear device

A flexible external gear of a silk hat shaped wave gear device has an annular body, external teeth formed on an outer circumferential portion of a first opening of the body, a circular diaphragm connected to a second opening portion of the body, and a circular boss connected to an outer circumferential end of the diaphragm. The shape of a connected portion of the diaphragm and the body is defined by a curved portion whose diameter decreases gradually from the diaphragm toward the body when viewed along a device axis. Since the body is wider on the diaphragm side, the wave generatorcan be easily fitted into the flexible external gear from the diaphragm side.

Silk hat shaped wave gear device

A lightweight wave gear device has a similar engagement rigidity, tooth surface hardness, and abrasion resistance as when a ferrous material is used. A cup-shaped wave gear device has a rigid internal gear that is formed of a lightweight alloy, such as an aluminum alloy, and internal teeth are formed with a height that is 1.1 to 1.3 times the height used for internal gears that are made of a ferrous material. A hard, electrolessly plated coating is also formed on the tooth surface of the internal teeth . By doing so, a lightweight wave gear device can be obtained with a similar engagement rigidity, tooth surface strength, and abrasion resistance to a wave gear device that has a rigid internal gear formed of a ferrous material.

Growing community of inventors

Nagano-ken, Japan

Yoshihiro Tanioka