Hollow-type strain wave gearing unit

Patent metadata

Field	Value
Publication number	US-9382993-B2
Application number	US-201314398749-A
Country	US
Kind code	B2
Filing date	Jun 20, 2013
Priority date	Jun 20, 2013
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A hollow-type strain wave gearing unit ( 1 ) has a sealing member ( 14 ) for sealing a gap ( 15 ) opening to the inner peripheral surface of a unit hollow portion ( 5 ) passing through in an axis ( 1 a ) direction. The gap ( 15 ) includes a gap section ( 15 b ) between an outer peripheral side end race ( 48 b ) on the wave generator side and a boss side end face ( 108 ), both faces opposing each other in the axis ( 1 a ) direction, and the sealing member ( 14 ) is assembled therein. The gap section ( 15 b ) is formed in a state partially entering the inside of the inner ring ( 11 b ) of the second bearing ( 11 ) supporting the wave generator ( 4 ). It is possible to realize a hollow-type strain wave gearing unit with a sealing mechanism that is suitable for increasing the inner diameter of the unit hollow portion and for reducing the unit axial length.

First claim

The invention claimed is:

1. A hollow-type strain wave gearing unit, comprising:
a rigid internally-toothed gear;
a cup-shaped flexible externally-toothed gear inside the rigid internally-toothed gear, and capable of meshing with the rigid internally-toothed gear;
a wave generator disposed inside the flexible externally-toothed gear and flexes the externally-toothed gear into an ellipsoidal shape to mesh partially with the rigid internally-toothed gear;
a boss side hollow part extending and passing through a boss in an axis direction, the boss defining a center portion of a cup bottom of the flexible externally-toothed gear;
a wave generator side hollow part extending and passing through the wave generator in the axis direction; and
an annular sealing member for sealing an annular gap opening to an inner peripheral surface of a unit hollow portion, the unit hollow portion extending in the axis direction and the unit hollow portion being defined by the boss side hollow part and the wave-generator side hollow part, wherein
the gap is formed between a boss side end face that is formed on a side of the boss, and a wave generator side end face that is formed on a side of the wave generator and faces the boss side end surface in the axis direction,
the wave generator side end face has an annular inner peripheral side end face, and an annular outer peripheral side end face that is positioned set back in the axis direction from the inner peripheral side end face with respect to the boss side end face, and
the sealing member is assembled in an annular gap section formed between the outer peripheral side end face and the boss side end face in the gap.

2. The hollow-type strain wave gearing unit according to claim 1 , wherein
the wave generator has a hollow rotation shaft defining the wave generator side hollow part,
the hollow rotation shaft has a first shaft end portion located on an opening side of the flexible externally-toothed gear, and the first shaft end portion is supported rotatably by the rigid internally-toothed gear via a first bearing,
a second bearing is arranged inside the flexible externally-toothed gear and is held by a bearing holder fixed to the boss,
the hollow rotation shaft has a second shaft end portion supported rotationally by the flexible externally-toothed gear via the second bearing,
the bearing holder has an annular boss fixing portion fixed to the boss, and a center through hole of the boss fixing portion is the boss side hollow part,
an end face of the boss fixing portion is the boss side end face,
a shaft end face of the second shaft end of the hollow rotation shaft is the wave generator side end face,
the gap section where the sealing member is assembled is formed in a state in which a part of the gap section enters an inside of an inner ring of the second bearing.

3. The hollow-type strain wave gearing unit according to claim 2 , wherein
the rigid internally-toothed gear has a first shaft end face on a side of the first shaft end portion and the first shaft end face is integrally formed with a first unit end plate,
the first bearing is mounted between an inner peripheral surface of the first unit end plate and an outer peripheral surface of the first shaft end portion,
a gap is formed between the inner peripheral surface of the first unit end plate and the outer peripheral surface of the first shaft end portion and is sealed by an annular oil seal arranged outer side in the axis direction of the first bearing,
a second unit end plate is fixed to a portion of the boss on an opposite side to the bearing holder,
the second unit end plate is supported rotatably by the rigid internally-toothed gear via a unit bearing,
one of inner and outer rings of the unit bearing is integrally formed on the second unit end plate, and
a gap between the inner and outer rings of the unit bearing is sealed by an annular second oil seal.

Assignees

• Harmonic Drive Systems

Inventors

• Murayama Yuya
• Kiyosawa Yoshihide

Classifications

• F16H2057/02073

  Reduction gearboxes for industry · CPC title

• F16H57/029

  characterised by means for sealing the gearboxes, e.g. to improve airtightness · CPC title

• F16H49/001 Primary

  Wave gearings, e.g. harmonic drive transmissions · CPC title

• F16H1/32

  in which the central axis of the gearing lies inside the periphery of an orbital gear · CPC title

• F16H1/02

  without gears having orbital motion · CPC title