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US 6,682,220 B2Granted
Lightweight bearing and wave gear drive
AssigneeHarmonic Drive Systems Inc.
InventorMasaru Kobayashi
Life of this patent
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AssigneeHarmonic Drive Systems Inc.
InventorMasaru Kobayashi
Estimating the term…
A lightweight bearing and wave gear drive are provided. An outer or inner bearing ring of the bearing has fixing holes to enable the ring to be attached to another member. The parts of the bearing on which raceway surfaces are formed are made of an iron-based material, while the main bearing ring member is formed of a lightweight material that is lighter than the iron-based material. Surface portions that constitute fixing bolt seats are plated to increase the strength of such portions. The wave gear drive includes a rigid internal gear, a flexible external gear located inside the internal gear, and a wave generator located inside the external gear. The internal and external gears are coupled by the lightweight bearing in a way that allows the gears to rotate relative to each other.
A lightweight bearing in which at least an outer or inner bearing ring has fixing holes formed therein for fixing the ring to another member, the bearing ring comprising:
Dependencies are inferred from the claim text.
From the US filing history. Foreign family members aren’t listed.
No references of this kind are recorded.
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Raceways; Race rings: divided or split, e.g. comprising two juxtaposed rings
Other gearings: wave gearings, e.g. harmonic drive transmissions
Cooling or heating: metallic
Machine element or mechanism: gearing
Term ended 21 May 2022 (estimated)
1. Field of the Invention
The present invention relates to a lightweight bearing, and to a wave gear drive in which a rigid, circular internal gear and a flexible, circular external gear are coupled by the lightweight bearing so that the gears can rotate relative to each other.
2. Description of the Prior Art
FIG. 1 is a cross-sectional diagram of a cup-shaped wave gear drive unit according to the present invention.
FIG. 2 is a diagram for explaining the cup-shaped wave gear drive unit of FIG. 1.
A wave gear drive unit that applies the present invention will now be described, with reference to FIG. 1, which is a cross-sectional diagram of a cup-shaped wave gear drive unit according to the present invention, and FIG. 2, which shows the configuration of the wave gear drive. The wave gear drive 110 of the wave gear drive unit 100 includes a circular, rigid internal gear 120 having internal teeth 123 provided on its inner peripheral surface, a cup-shaped, flexible external gear 130 disposed inside the rigid internal gear 120, and an elliptical wave generator 140 disposed inside the flexible external gear 130. The flexible external gear 130 and rigid internal gear 120 are rotatably supported by a cross-roller bearing 150 in a way that enables the gears 130 and 120 to rotate relative to each other. The rigid internal gear 120 is a composite part consisting of a cylindrical main gear member 121 and a teeth formation member 122 integrally affixed to an inside peripheral edge of the main gear member 121. Internal teeth 123 are provided on an inner peripheral surface of the teeth formation member 122.
The cup-shaped flexible external gear 130 includes a cylindrical body 131, external teeth 132 formed on an outer periphery around an opening at one end of the body 131, a circular diaphragm 133 formed integrally at an opening at the other end of the body 131, and a thick, annular boss 134 formed integrally with the diaphragm 133. The wave generator 140 comprises a rigid, elliptical cam plate 141 and a ball bearing 142 mounted on an outer periphery of the rigid cam plate 141. The rigid cam plate 141 has an axial hole 143 for coupling to a motor output shaft (not shown).
The cross-roller bearing 150 includes an outer ring 151, an inner ring 155, and a plurality of rollers 160 disposed in a circular raceway provided between the outer and inner rings 151 and 155. The outer ring 151 is a composite part consisting of an annular outer-ring body member 152 and an annular outer-ring raceway formation member 153 on an inside of the member 152. An inner peripheral surface of the outer-ring raceway formation member 153 is formed as a V-shaped raceway surface. The outer ring 151 thus configured is attached to a circular end face of the rigid internal gear 120 by bolts 154.