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公开(公告)号：US10935121B2
公开(公告)日：2021-03-02
申请号：US16611248
申请日：2017-06-16
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Masaru Kobayashi
Abstract: A strain wave gearing has a rigid internally toothed gear, a flexible externally toothed gear, and a sliding-contact type wave generator. The wave generator has: a plurality of gear pressing members that flexes the externally toothed gear in the radial direction at positions at equal angular intervals in the circumferential direction to form plurality of meshing portions which mesh with the internally toothed gear; and piezoelectric elements that generate ultrasonic vibration of 20 kHz to 80 kHz in the gear pressing members in the radial direction. Ultrasonic vibration is applied at contact sites where the gear pressing members and the externally toothed gear contact each other. As a result of a squeeze film effect, the apparent friction coefficient of each contact surface at the contact sites can be greatly reduced and rotational torque, of the wave generator can be reduced.
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公开(公告)号：US20210018081A1
公开(公告)日：2021-01-21
申请号：US16907477
申请日：2020-06-22
Applicant: Harmonic Drive Systems Inc.
Inventor： Takeo KODAIRA
Abstract: A strain wave gearing has a cup-shaped externally toothed gear that is provided with a body formed with external teeth, a diaphragm extending from an end of the body, and a rigid boss integrally formed in the diaphragm. The ratio B/A is set equal to or less than 0.59 where A is the reference pitch circle diameter of the external teeth and B is the outer diameter of the boss. The radial length from the inner peripheral edge of the diaphragm to the outer peripheral edge thereof in the present externally toothed gear is large. This enables to reduce bending stress generated in each part of the externally toothed gear due to coning, and a meshing state of the external teeth with the internal teeth in the tooth trace direction can also be improved, whereby further flattening of the externally toothed gear can be realized.
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公开(公告)号：US10883592B2
公开(公告)日：2021-01-05
申请号：US16477227
申请日：2017-12-08
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Norio Shirokoshi
Abstract: A strain wave gearing has a rigid internally toothed gear, a flexible externally toothed gear, and a wave generator. Before being flexed by the wave generator, the externally toothed gear has a cylindrical body part, an inside diameter of which is such that the inside diameter D is smallest at a rear end thereof and increases gradually from the rear end to an opening end thereof. After being flexed by the wave generator, D1≤D is satisfied where D1 is the minor diameter of an elliptical inner circumferential surface of the opening end of the cylindrical body part. The externally toothed gear, which is provided with such a tapered cylindrical body part, is suitable for manufacturing by die molding such as casting, and can also alleviate excessive uneven contact thereof with a wave bearing.
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公开(公告)号：US10801585B2
公开(公告)日：2020-10-13
申请号：US15766534
申请日：2015-11-06
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Masaru Kobayashi , Tatsuro Hoshina
Abstract: The flexible external gear of a strain wave gearing is provided with: a cylindrical body part capable of flexing in the radial direction; external teeth formed on the outer circumferential surface thereof with a constant pitch; and grooves formed on the inner circumferential surface of the cylindrical body section along the circumferential direction thereof with the same pitch as the external teeth. The grooves are grooves with a wave-shaped cross-sectional shape having the center line of the tooth crest of the external tooth as the center and extend in the width direction of the external teeth. It is possible to increase the tooth bottom fatigue strength of the flexible external gear by increasing the tooth bottom thickness, while maintaining ease of flexing and a tooth shape that can withstand tangential forces due to meshing.
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公开(公告)号：US10788115B2
公开(公告)日：2020-09-29
申请号：US16068383
申请日：2016-01-15
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Shoichi Ishikawa
Abstract: In a strain wave gearing, the addendum tooth profile of an internal gear is defined by the formula a and that of an external gear is by the formula b at a principal cross-section located at a tooth-trace-direction center of the external gear, on the basis of a movement locus (Mc) of κ=1 of the teeth of the external gear with respect to those of the internal gear in the principle cross-section taken at the center of the tooth trace of the external gear obtained when the tooth meshing is approximated by rack meshing. It is possible to avoid superimposition of flexion-induced bending stresses and tensile stresses caused by load torque at the major-axis locations of the external gear, and the transmission torque capacity of a strain wave gearing can be improved.
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Patent Agency Ranking
公开(公告)号：US20200284332A1
公开(公告)日：2020-09-10
申请号：US16305598
申请日：2016-07-30
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Masaru KOBAYASHI
Abstract: A wave bearing of a wave generator of a strain wave gearing is provided with steel or stainless steel cylindrical hollow rollers between an inner-race-side raceway surface and an outer-race-side raceway surface, the hollow rollers serving as rolling elements. The ratio Di/Do of the inner diameter Di to the outer diameter Do of the hollow rollers is set to 0.95 or more. The relative radius of curvature of hollow rollers that have been flexed into an ellipsoidal shape increases with respect to the inner-race raceway surface and the outer-race raceway surface with which the hollow rollers are in contact, and the Hertz maximum contact stress is reduced. The hardness of the hollow rollers, the inner-race raceway surface, and the outer-race raceway surface can be reduced.
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公开(公告)号：US10753427B2
公开(公告)日：2020-08-25
申请号：US16091203
申请日：2016-05-11
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Hiroshi Nakagawa , Daisuke Yaguchi
Abstract: A rotary actuator has: one motor, two strain wave reduction gears disposed symmetrically on both sides of the motor, and one output shaft. The output rotation of the motor is reduced in speed at the same reduction ratio by the two strain wave reduction gears and is outputted from the output shaft to a load side. The first and second externally toothed gears of the first and second strain wave reduction gears are flexed into ellipsoidal shapes with 90 degrees shifted in phase, and are meshed with first and second internally toothed gears. The angle transmission errors of the first and second strain wave reduction gears transmitted to the output shaft are reduced by cancelling each other out in the output shaft. Reduced-speed output rotation that has the reduced angle transmission errors is outputted to the load side from the output shaft.
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公开(公告)号：US10718419B2
公开(公告)日：2020-07-21
申请号：US15528706
申请日：2014-11-28
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Masaru Kobayashi
IPC: F16H49/00 , F16H57/04 , C10M103/00 , C10M103/02 , C10M103/06 , C10M171/06 , F16H1/32 , C10N20/06 , C10N30/06 , C10N40/04 , C10N50/08 , F16J15/50
Abstract: A strain wave gearing has contact parts which are the portions to be lubricated other than the teeth of an externally toothed gear and an internally toothed gear, the contact parts being respectively lubricated with an inorganic lubricating powder having a lamellar crystal structure. The lubricating powder, during the operation of the strain wave gearing, is crushed between the contact surfaces of each of the contact parts to move and adhere to the contact surfaces, thereby forming thin surface films thereon. Additionally, the powder is thinly spread by pressure and reduced into finer particles to change into a shape which facilitates intrusion into the space between the contact surfaces. By both the fine particles having changed in shape and the surface films, the lubrication of the contact parts is maintained. Neither the fine particles nor the surface films are viscous.
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公开(公告)号：US20200173532A1
公开(公告)日：2020-06-04
申请号：US16640197
申请日：2017-09-07
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Norio SHIROKOSHI
Abstract: A strain wave gearing has a wave generator that is provided with a rigid cam plate and a wave bearing. The wave bearing is mounted between the elliptical outer peripheral surface of the rigid cam plate and the inner peripheral surface of an externally toothed gear so as to support the rigid cam plate and the externally toothed gear in a relatively rotatable state. The wave bearing is a full complement ball bearing provided with inner and outer races which are flexible in a radial direction. Since the wave bearing is not provided with a retainer and the number of balls inserted in a ball raceway is not restricted by partition walls of such a retainer, the maximum number of balls can be mounted. Thus, the wave bearing with a large load capacity can be realized, and reliability during high-load operation of the strain wave gearing is enhanced.
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公开(公告)号：US20200056653A1
公开(公告)日：2020-02-20
申请号：US16346941
申请日：2018-08-30
Applicant: HARMONIC DRIVE SYSTEMS INC.
Inventor： Hiroaki KIMURA , Jun HANDA
Abstract: 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. Where L1 is the maximum width of the gap, t1 is a depth from the tooth top land of the first external teeth to the deepest part of the gap, h1 is the tooth depth of the first external teeth, t2 is a depth from the tooth top land of the second external teeth to the deepest part, and h2 is the tooth depth of the second external teeth, any one of the following conditions 1 to 3 is satisfied: L1=0.1L−0.35L, t1=0.9h1−1.3h1, and t2=0.3h2−0.9h2 Condition 1: L1=0.1L−0.35L, t1=0.3h1−0.9h1, and t2=0.9h2−1.3h2 Condition 2: L1=0.1L−0.35L, t1=0.3h1−0.9h1, and t2=0.3h2−0.9h2 Condition 3: It is possible to obtain a dual-type strain wave gearing in which wear resistance and tooth bottom fatigue strength are increased.
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