Harmonic Drive Systems Inc.

Nissan Motor Company Limited

Hitachi Automotive Systems, Ltd.

Sumitomo Metal Industries, Inc.

Harminic Drive Systems Inc.

Yoshihide Kiyosawa

Jun Handa

Noboru Takizawa

Xin Yue Zhang

Masaru Kobayashi

Norio Shirokoshi

Akio Ikeda

Yuya Murayama

XinYue Zhang

Yoshiaki Tanaka

Ryosuke Hiyoshi

Yoshihiko Yamada

Shoichi Ishikawa

Hiroaki Kimura

Kishiro Nagai

Junichiro Onigata

Tatsuro Hoshina

Hideo Asawa

Hiroki Hanaoka

Shoji Kuwana

Hiroshi Yamazaki

Daisuke Orii

Sotaro Miyake

Keiji Ueura

Yoshitomo Mizoguchi

Harushige Aoyagi

Toshimi Yamagishi

Junichi Kurogi

Shunichi Tezuka

Hideo Yasue

Manabu Kino

Satoshi Kishi

Kazuo Tanaka

Takahiro Oukura

Yoshito Yamamoto

Jun Sakata

Toshiaki Misawa

Hiroshi Takizawa

Yu Nakagawa

Sohei Beppu

A wave bearing of a space strain wave gearing device comprises an inner ring formed from a bearing steel, an outer ring formed from a martensitic stainless steel, and balls formed from ceramics. On the inner ring formed from a bearing steel, a ceramic coating formed by an AD method is formed as a rust-preventive coating. In the space strain wave gearing device that adopts solid lubrication (powder lubrication), it is possible to reliably prevent rust from developing on the inner ring formed from a bearing steel of the wave bearing. In a space environment where the temperature greatly changes, appropriate setting of the linear expansion coefficients of the inner ring, the outer ring, and the balls enables a change in the radial gap of the wave bearing to be suppressed to a range that does not interfere with practical use.

Space rolling bearing and space strain wave gearing device

A lubrication mechanism of a strain wave gearing is disposed in an interior space of an externally toothed gear and comprises a powder-accommodating bag that stores solid lubricant powder. A diaphragm of the externally toothed gear is repeatedly deflected during the driving of the strain wave gearing. Vibration or deflection is repeatedly imparted to the powder-accommodating bag and the solid lubricant powder is discharged from a powder discharge hole formed in the powder-accommodating bag into the interior space. A site to be lubricated is lubricated with the solid lubricant powder discharged into the interior space. Harmful effects due to a large amount of the solid lubricant powder being supplied to the site to be lubricated at one time can be resolved, and a necessary amount of the solid lubricant powder can be continuously supplied to the site to be lubricated.

Lubrication method for gear device

A three-dimensional tooth profile of internal teeth in a strain wave gearing is a basic internal-teeth tooth profile at an internal-teeth outer end, and is a reduced tooth profile, in which the basic internal-teeth tooth profile is proportionally reduced only in the lateral direction, at other tooth-trace-direction positions. A three-dimensional tooth profile of external teeth is a basic external-teeth tooth profile at an external-teeth outer end, and is an increased tooth profile, in which the basic external-teeth tooth profile is proportionally increased only in the lateral direction, at other tooth-trace-direction positions. Tooth cutting process becomes easier than when only the external teeth employ a three-dimensional tooth profile. Since the tooth profiles, which are proportionally reduced and increased only in the lateral direction along the tooth trace direction, are employed, it is further easier in tooth cutting process.

Strain wave gearing provided with three-dimensional tooth profile

Speed reducer

A cup-type strain wave gearing having a unit structure and having: a stationary-side part including a unit housing and an internally toothed gear; a driving-side part including an output member and an externally toothed gear; and a sliding bearing supporting the stationary-side part and the driving-side part in the radial direction and the thrust direction in a state in which relative rotation is possible. The sliding bearing has a cylindrical bushing accommodated in a radial gap, and annular bushings accommodated respectively in thrust gaps. Thus, it is possible to provide an advantageous strain wave gearing having a unit structure that is more lightweight and compact than when a rolling bearing is used.

Strain wave gearing having unit structure

In a unit-type strain wave gearing, a rotating-side member, which is constituted by a second internally toothed gear and an output shaft is supported, via a first sliding bearing and a second sliding bearing, on a fixed-side member so as to be capable of relative rotation, the fixed-side member being constituted by a unit housing and a first internally toothed gear. Sliding bearing surfaces of the first sliding bearing and sliding bearing surfaces of the second sliding bearing are defined by a conic surface having a central axis line as a center line. It is possible to realize a unit-type strain wave gearing which is advantageous in making smaller and more compact than when a roller bearing is used. It is also easier to adjust the gap between the sliding bearing surfaces because a radial sliding bearing having no function to adjust the radial gap is obviated.

Unit-type strain wave gearing

An externally toothed gear of a dual-type strain wave gearing is provided with first and second external teeth having different teeth numbers, and a gap formed between these teeth as a cutter clearance area for tooth cutters. The maximum width Lof the gap is 0.1 to 0.3 times the width L of the externally toothed gear. The depth from the tooth top land of the first external teeth to the deepest part of the gap is 0.9 to 1.3 times the depth of the first external teeth, and the depth from the tooth top land of the second external teeth to the deepest part of the gap is 0.9 to 1.3 times the depth of the second external teeth. The tooth bottom fatigue strength of the externally toothed gear provided with differing numbers of first and second external teeth is increased.

Dual-type strain wave gearing

A rotary actuator has a hollow motor and hollow reduction gears arranged coaxially on either side of the hollow motor. A rotary shaft is arranged so as to pass through a hollow motor shaft of the hollow motor. The hollow reduction gears have hollow input shafts connected to the shaft ends on either sides of the hollow motor shaft. The hollow reduction gears have hollow output shafts connected to sections of the rotary shaft protruding from both ends of the hollow motor shaft. The connection position of the hollow output shaft with respect to the rotary shaft can be adjusted in the rotational direction. A load is rotationally driven by the rotary shaft. By increasing the axial length of the hollow motor, it is possible to obtain a small-diameter rotary actuator having a rotational output with large torque.

Rotary actuator and linear actuator

A silk hat-type strain wave gear device has a crossed roller bearing for supporting an internal gear and an external gear so as to allow relative rotation. A first gap part between the inner and outer rings of said bearing is sealed by an oil seal and a second gap part thereof is in communication with a gear-side gap part on the outside of the external gear. A bearing seal separates the second gap part from the gear-side gap part. The bearing seal prevents excessive inflow of lubricant from the gear-side gap part into the second gap part. Excess lubricant that has flowed into the bearing can flow back from the second gap part to the gear-side gap part. Excess lubricant in the bearing is prevented from leaking through the oil seal to the outside.

Silk hat-type strain wave gear device

A variable compression ratio mechanism for an internal combustion engine includes a gear reducer that varies an engine compression ratio. The gear reducer includes an input-side member connected to a rotation shaft of the actuator; an output-side member that transmits a reduced rotation of the actuator to the control shaft; a fixed member fixed to a housing of the actuator; and an intermediate member that transmits torque from the input-side member to the output-side member and the fixed member, and has a first gear portion engaged with the fixed member and a second gear portion engaged with the output-side member. A ratio of a number of teeth of the fixed gear portion to a number of teeth of the first gear portion is higher than a ratio of a number of teeth of the output-side gear portion to a number of teeth of the second gear portion.

Variable compression ratio mechanism for internal combustion engine

A variable compression ratio mechanism for an internal combustion engine includes a gear reducer that varies an engine compression ratio. The gear reducer includes an input-side member connected to a rotation shaft of an actuator; an output-side member that transmits a reduced rotation of the actuator to the control shaft; a fixed member fixed to a housing of the actuator; and an intermediate member that transmits torque from the input-side member to the output-side member and the fixed member, and has a first gear portion engaged with the fixed member and a second gear portion engaged with the output-side member. A ratio of a number of teeth of the fixed gear portion to a number of teeth of the first gear portion is lower than a ratio of a number of teeth of the output-side gear portion to a number of teeth of the second gear portion.

A relieving portion is formed between a first external tooth portion and a second external tooth portion in the external teeth of a flexible externally toothed gear of a flat strain wave gearing. The length Lof the relieving portion in the tooth trace direction is within the range of 0.1 to 0.5 of the tooth width L of the external teeth. The maximum relieving amount t from the tooth top land of an external tooth in the relieving portion is 3.3&#xd7;10&#x3c;t/PCD&#x3c;6.3&#xd7;10where the PCT is defined as the pitch circle diameter of the external teeth. The tooth face load distribution of the external tooth in the tooth trace direction can be equalized, and a flat strain wave gearing having a high transmitted-load capacity can be achieved.

Flat strain wave gearing

An externally toothed gear of a dual-type strain wave gearing is provided with first and second external teeth having different teeth numbers, and is flexed into an ellipsoidal shape by a wave generator. When the theoretical values of the radial flexing amounts at major-axis positions of the first and second external teeth flexed into the ellipsoidal shape are expressed by d1=m1n1 and d2=m2n2 (m1 and m2 represent the modules of the first and second external teeth, and n1 and n2 represent positive integers), the radial flexing amounts of the first and second external teeth flexed by the wave generator satisfy d1a=&#x3c9;d1 and d2a=&#x3c9;d2, where 1.25&#x2264;&#x3c9;&#x2264;3. Accordingly, a dual-type strain wave gearing can be achieved with which the first and second external teeth having different numbers can be suitably flexed to form excellent mating states with respective internally toothed gears.

An externally toothed gear of a dual-type strain wave gearing is provided with first and second external teeth having different tooth numbers, and is flexed into an ellipsoidal shape by a wave generator. When the theoretical values of the radial flexing amounts at major-axis positions of the first and second external teeth flexed into the ellipsoidal shape are expressed by d=mnand d=mn(mand mrepresent the modules of the first and second external teeth, and nand nrepresent positive integers), the radial flexing amount of the first and second external teeth flexed by the wave generator satisfies d=(d+d)/&#x3c9;(1.4&#x2264;&#x3c9;&#x2264;2.6). Accordingly, a dual-type strain wave gearing can be achieved with which the first and second external teeth having different numbers can be suitably flexed to form excellent mating states with respective internally toothed gears.

Growing community of inventors

Azumino, Japan

Yoshihide Kiyosawa