Teijin Seiki Co., Ltd.

Teijin Seiko Co., Ltd.

Masataka Hashimoto

Michiyoshi Iwata

Kazuyuki Matsumoto

Osamu Nohara

Hong You Wang

When the load acting on a fluid motor ( ) increases, a changeover valve ( ) starts to be changed over toward a low-speed position L, but at this time an additional pilot fluid whose pressure is determined by the amount of fluid flowing into or out of a second passage ( ) through first and second notches functions as a pressure regulator for a spool ( ), and lowers the pressure within the second passage ( ) without lowering the pressure within a high pressure-side main circuit ( ), thereby tilting a swash plate ( ) from a position of high-speed rotation to a position of low-speed rotation.

Drive circuit for fluid motor

A planetary gear apparatus comprising an inner tooth gear having an inner peripheral portion formed with a plurality of inner teeth each in the form of a semi-circular cross-section shape and an outer tooth gear positioned within the inner tooth gear and having an outer peripheral portion formed with a plurality of outer teeth each in the form of a wave shape. The outer tooth gear has a center axis offset at an offset amount from the center axis of the inner tooth gear, and revolvable while being held in sliding and meshing contact with the inner tooth gear with the center axis of the outer tooth gear moving on a revolution orbit encircling and spaced from the center axis of the inner tooth gear at a distance equal to the offset amount. The outer teeth of the outer tooth gear have their respective tooth profiles each including deddendum and addendum portions, and a pair of tooth engaging portions each connected at its deddendum side end with the deddendum portion and at its addendum side end with the addendum portion. In the planetary gear apparatus, each of the tooth engaging portions of the tooth profiles has an epitrochoidal tooth surface extending on a theoretical epitrochoid curve having a central point coincident wit the center axis of the outer tooth gear, and the epitrochoidal tooth surfaces of the outer teeth are partly continually held in pressing contact with the inner teeth of the inner tooth gear even under the state that no load torque is applied to the outer tooth gear. The deddendum and addendum portions of the tooth profile of the outer tooth are closer to the center axis of the outer tooth gear than the theoretical epitrochoid cure, thereby making it possible to have the deddendum and addendum portions held out of contact with the inner teeth of the inner tooth gear even under the state that a certain load torque is exerted on the outer tooth gear.

Outer tooth profile of planetary gear apparatus

A robot arm drive apparatus of an industrial robot comprising: an electric motor having a drive shaft; a first robot member having the electric motor mounted thereon; a second robot member rotatably supported on the first robot member; and reduction gears for reducing rotation of the electric motor and then transmitting to the second robot member; the reduction gears comprising a planetary reduction gear and furthermore an additional reduction gear which is purposely provided so that the number of rotations of the electric motor, at which the resonance of a drive system comprising the electric motor, the second robot member and the reduction gear means occurs, is shifted from a predetermined operational region of the electric motor. The planetary reduction gear comprises an input shaft having a cam surface and connected with the additional reduction gear, an external gear, an internal gear held in mesh with the external gear and different in number of teeth from the external gear, the external gear being connected to the cam surface of the input shaft in such a manner that differential motion between the external gear and the internal gear is developed.

Growing community of inventors

Gifu, Japan

Masataka Hashimoto