VARIABLE RATIO ROTARY MOTION TRANSMITTING DEVICE

• US 3,820,416 A
• Filed: 01/05/1973
• Issued: 06/28/1974
• Est. Priority Date: 01/05/1973
• Status: Expired due to Term

• Current Assignee: NSK Limited
• Original Assignee: Kraus C
• Inventors: KRAUS C
• Application Number:
  US05/321,452
• Time in Patent Office: 539 Days
• US Class Current: 475/185
• CPC Class Codes: F16H 15/38 with two members B having hollow toroid surfaces opposite to each other, the member or members A being adjustably mounted between the surfaces
• CPC Class Codes: F16H 2015/383 with two or more sets of toroid gearings arranged in parallel

Abstract

A variable ratio rotary motion transmitting device having a toric input and output traction disc disposed at opposite sides of an intermediate traction disc and coupled to input and output shafts. The intermediate traction disc has a toric surface formed at each side corresponding to the toric surfaces formed on the facing input and output traction discs. Motion transmitting means are disposed between the output and input traction discs and the intermediate traction disc and engage the toric surfaces at variable circles of contact.

Claims

1. A variable ratio rotary motion transmitting device, comprising coaxial input and output shafts, an input toric traction disc mounted for rotation with the input shaft and an output toric traction disc mounted for rotation about the axis of the input and output shafts, an intermediate traction disc disposed between the input and output traction discs, said intermeDiate traction disc having toric surfaces respectively facing a corresponding toric surface of the adjacent input and output traction discs, motion transmitting means disposed between and engaging the toric surfaces of said input and intermediate traction discs and said intermediate and output traction discs, respectively, for the transmission of motion from the input to the intermediate traction disc and from the intermediate traction disc to the output traction disc at variable circles of contact, means for forcing said input and output traction discs toward each other to cause frictional engagement between the motion transmitting means and the traction discs and means for coupling said output traction disc with said output shaft.

2. A rotary motion transmitting device as claimed in claim 1, wherein at least the motion transmitting means disposed between the intermediate and the output traction discs are traction rollers causing rotation of the intermediate and output traction discs in opposite directions and means are provided for selectively coupling said output shaft with either one of said intermediate and output traction discs.

3. A rotary motion transmitting device as claimed in claim 2, wherein said intermediate and said output traction discs are mounted on concentric shafts, the intermediate traction disc shaft extending through the output traction disc shaft, and said means for selectively coupling the output shaft with either one of the intermediate and output traction discs are clutches adapted to couple said output shaft to either one of said concentric shafts.

4. A rotary motion transmitting device as claimed in claim 3, wherein a planetary speed reduction drive is associated with each of said concentric shafts, each of said planetary speed reduction drives having a sun member formed by one of said concentric shafts and its drive rim connected to one of said clutches.

5. A rotary motion transmitting device as claimed in claim 4, wherein said planetary speed reduction drives are friction roller planetary drives.

6. A rotary motion transmitting device as claimed in claim 1, wherein a hydraulically operated drive clutch is associated with the input shaft for connecting the input shaft to a motor and wherein hydrostatic axial thrust bearings are provided for axially supporting the input and output traction discs, said hydraulically operated clutch being supplied by the same source of hydraulic pressure as the axial thrust bearings to permit engagement of the drive clutch only when pressurized fluid is also supplied to axial thrust bearings.