Abstract: Provided are an actuator for a link mechanism for an internal combustion engine and a wave gear speed reducer, which improve both input efficiency and driving efficiency. According to the invention, the wave gear speed reducer is configured so that a flexible external gear is bent into an elliptical shape using a wave generating device rotated by an input shaft to partially engage external teeth of the flexible external gear with internal teeth of an internal gear portion, and further configured so that an engaging part between the flexible external gear and the internal gear portion is rotated. The external teeth are larger in curvature than the internal teeth in a contact portion between the internal and external teeth.

Abstract: Provided is an actuator for a link mechanism for an internal combustion engine, which can be prevented from being increased in size in an axial direction. The actuator for a link mechanism for an internal combustion engine of the present invention includes: a wave gear type speed reducer configured to reduce a rotation speed of an electric motor, and to transmit the rotation speed to the control shaft; and a housing to which the electric motor and the wave gear type speed reducer are fixed, the wave gear type speed reducer including: an inner gear, which is fixed to the housing, has inner teeth meshed with the flexible outer gear, and is made of an iron-based metal material, the actuator including a stopper mechanism, which is provided to each of the inner gear and the control shaft, and is configured to restrict relative rotation of a predetermined amount or more when the inner gear and the control shaft are held in abutment against each other.

Abstract: Provided is an actuator of a link mechanism for an internal combustion engine, in which a speed reducer is sufficiently lubricated. The actuator includes an oil passage formed in a control shaft for changing the posture of a control link and configured to feed lubricant oil to the speed reducer; and an open portion which opens to face the speed reducer in one end side located on the speed reducer side, and which is in communication with the oil passage in the other end side. An inner diameter of the one end side of the open portion is larger than an outer diameter of one end side of the oil passage.

Abstract: Provided is an actuator for a link mechanism for an internal combustion engine, which can be prevented from being increased in size in an axial direction. The actuator for a link mechanism for an internal combustion engine of the present invention includes: a wave gear type speed reducer configured to reduce a rotation speed of an electric motor, and to transmit the rotation speed to the control shaft; and a housing to which the electric motor and the wave gear type speed reducer are fixed, the wave gear type speed reducer including: an inner gear, which is fixed to the housing, has inner teeth meshed with the flexible outer gear, and is made of an iron-based metal material, the actuator including a stopper mechanism, which is provided to each of the inner gear and the control shaft, and is configured to restrict relative rotation of a predetermined amount or more when the inner gear and the control shaft are held in abutment against each other.

Abstract: Provided is an actuator of a link mechanism for an internal combustion engine, in which a speed reducer is sufficiently lubricated. The actuator includes an oil passage formed in a control shaft for changing the posture of a control link and configured to feed lubricant oil to the speed reducer; and an open portion which opens to face the speed reducer in one end side located on the speed reducer side, and which is in communication with the oil passage in the other end side. An inner diameter of the one end side of the open portion is larger than an outer diameter of one end side of the oil passage.

Abstract: An electric motor includes a motor casing formed with a shaft insertion hole and a motor output shaft extending in the shaft insertion hole and projecting to a speed reducing mechanism. An annular oil seal is disposed between the shaft insertion hole and the motor output shaft and the annular oil seal includes an annular seal retainer buried in the annular oil seal for reinforcement. A C-shaped stopper member extending circumferentially from a first end to a second end spaced from the first end, is held in a holding portion or a fitting groove of the shaft insertion hole, and arranged to prevent movement of the oil seal toward the speed reducing mechanism. The stopper member includes a plurality of beam segments confronting the seal retainer from an axial direction of the motor output shaft.

Abstract: An electric motor includes a motor casing formed with a shaft insertion hole and a motor output shaft extending in the shaft insertion hole and projecting to a speed reducing mechanism. An annular oil seal is disposed between the shaft insertion hole and the motor output shaft and the annular oil seal includes an annular seal retainer buried in the annular oil seal for reinforcement. A C-shaped stopper member extending circumferentially from a first end to a second end spaced from the first end, is held in a holding portion or a fitting groove of the shaft insertion hole, and arranged to prevent movement of the oil seal toward the speed reducing mechanism. The stopper member includes a plurality of beam segments confronting the seal retainer from an axial direction of the motor output shaft.