Harmonic Drive Systems Inc.

Harmonic Ad, Inc.

Naomi Shirasawa

Norio Shirokoshi

Noboru Takizawa

Masashi Horiuchi

Hideo Asawa

Akihiro Yokoyama

A unit type wave gear device () has a unit housing (), one end of which is defined by a two-stage cross roller bearing (). The two-stage cross roller bearing () has: an inner cross roller bearing formed by an inner ring (), an intermediate ring (), and inner rollers () inserted into an inner track (); and has an outer cross roller bearing formed by an outer ring (), the intermediate ring (), and outer rollers () inserted into an outer track (). A flexible externally-toothed gear () affixed to the intermediate ring () is rotatably supported by the unit housing () via the outer cross roller bearing. An input shaft () affixed to the inner ring () and a wave generator () affixed to the input shaft () are rotatably supported by the intermediate ring () via the inner cross roller bearing. A unit type wave gear device can be realized in which the number of components are reduced and a large moment load is applied.

Unit type wave gear device

In a brake-equipped retracting mechanism, rotational force of a motor is used to open a liquid crystal display device from a retracted position to an open position, a power spring is wound up in conjunction with this opening operation, and elastic restoring force thereof is used to return the liquid crystal display device from the open position to the retracted position. A rope for developing a greater or smaller tensile force in conjunction with opening and closing of the liquid crystal display device is wound around a slip clutch linked to a reducer input shaft, whereby braking force for preventing the liquid crystal display device from an abrupt return is applied to the reducer input shaft. The braking force gradually decreases as the liquid crystal display device returns to the retracted position, and the liquid crystal display device can therefore be returned at a substantially constant speed.

Brake-equipped retracting mechanism for retractable member

A two-stage cross roller bearing () includes a first cross roller bearing () and a second cross roller bearing () that are disposed concentrically along a plane that is perpendicular to the bearing axis. The inner ring of the first cross roller bearing () and the outer ring of the second cross roller bearing () are formed of a single ring-shaped member (), with an inner ring-side raceway groove () of the first cross roller bearing being formed on the circular outer circumferential surface of the ring-shaped member and an outer ring-side raceway groove () of the second cross roller bearing being formed on the circular inner circumferential surface of the ring-shaped member. A small, compact, and flat multistage cross roller bearing is realized.

Multi-stage cross roller bearing

A planetary gear device includes a first, a second, and a third ring-shaped member that are concentrically arranged in that order from the inside. A sun gear is coaxially fixed to an end surface of the first ring-shaped member, planet shafts of planet gears are supported on an end surface of the ring-shaped member, and an internal gear is coaxially fixed to an end surface of the third ring-shaped member. A first cross roller bearing is formed between the first and second ring-shaped members and a second cross roller bearing is formed between the second and third ring-shaped members. Each member is arranged concentrically on a plane that is perpendicular to the device axis, so that a planetary gear device that is extremely slim in the device axial direction can be realized. Since the respective gear parts can be accessed from both sides in the device axial direction, the input and output can be laid out with great freedom.

Planetary gear device

A silk hat flexible engagement gear device (,) has first and second end plates (,) and an input shaft (,) is rotatably supported, with their ends supported, between the tow end plates. An annular body (,) of a silk hat flexible external gear (,) is disposed on the outer circumference of the input shaft (,). A cross roller bearing (,) and a rigid internal gear (,) which also function as a device housing are arranged on the outer circumference. An cylindrical boss (,) of the flexible external gear is held between the outer race (,) of the cross roller bearing and the second end plate (,) and these three members are coupled with one another by means of second fixing bolts (,). An additional member which is used as a device housing is not necessary. The members are temporarily fixed and fastened and, further, attached to a housing on the motor side or on the load side by the fixing bolts (,). Therefore, the number of components of the device can be reduced, whereby making the device small and compact.

Silk hat flexible engagement gear device

A cup-type wave gear device,comprises a cup-shaped flexible external gear,which has a boss,formed at its outer circumferential surface with an external thread,. An output shaft,is formed on Its end surface with an annular recess whose inner circumferential surface is formed with an internal thread,. The external thread,of the boss,is screwed into the internal thread,of the output shaft,. Further, driving pins,are used to fasten the boss,to the output shaft,. Whereby, the flexible external gear,is fixedly connected to the output shaft,The fastening torque between the boss and the output shaft can be increased in comparison with the conventional case where fastening bolts are used to connect these parts.

Cup-type wave gear device

A wave gear drive (1) has first and second end plates (2) and (3) arranged to rotate relative with each other by means of a cross roller bearing (4) positioned between the plates (2, 3). An inner race (41) of the cross roller bearing (4) is formed integrally on a circumferential Inner surface with an internal gear (11). The inner race (41) is directly fastened to the first end plate (2), while an outer race (44) of the cross roller bearing (4) is fastened to the second end plate in a manner such that a circular boss (17) of a flexible external gear is held between the outer race (44) and the second end plate (3). The internal teeth (11) are positioned approximately at a radially inner side of a raceway (47) of the cross roller bearing (4). Thus, the wave gear drive (1) is small and compact, and the rigidity is increased.

Wave gear drive

Flat wave gear drive

A wave gear device has a circular spline, a flexspline arranged within the circular spline, and a wave generator disposed within the flexspline for deflecting the flexspline in radial direction for partially engaging external tooth formed on the flexspline with internal gear teeth formed on the circular spline and shifting an engaging position in circumferential direction to cause relative rotation depending upon difference in number of teeth of the internal gear teeth and the external gear teeth between the circular spline and the flexspline. The circular spline has an annular rigid teeth portion formed with the internal gear teeth along the inner periphery thereof, a fastening portion to be rigidly secured on one of a device housing and a supporting member rotatably supported in the device housing, and a connecting portion connecting the rigid teeth portion and the fastening portion. The connecting portion has a low rigidity at least in one of a direction of an axis of the device and a direction perpendicular to the axis, in comparison with that of the rigid teeth portion.

Growing community of inventors

Nagano-ken, Japan

Naomi Shirasawa