Variable speed pulley

• US 4,789,378 A
• Filed: 06/29/1987
• Issued: 12/06/1988
• Est. Priority Date: 06/30/1986
• Status: Expired due to Fees

• Current Assignee: Mitsuboshi Belting Limited
• Original Assignee: Mitsuboshi Belting Limited
• Inventors: Takano, Hiroshi, Hashimato, Yasuhiro
• Primary Examiner(s): Bui, Thuy M.
• Application Number:
  US07/067,691
• Time in Patent Office: 526 Days
• Field of Search: 474/8, 474/11, 474/13-15, 474/69-70, 474/17-19, 474/28
• US Class Current: 474/13
• CPC Class Codes: F16H 55/563 actuated by centrifugal masses
• CPC Class Codes: F16H 61/66245 using purely mechanical sensing or control means

Abstract

A variable speed pulley having rearrangement structure for causing uniform distribution of a plurality of force applying elements utilized to control the width of the pulley groove as a function of the centrifugal forces developed during changes in the speed of the pulley. The rearrangement structure includes a coil spring connected in the structure to permit relative rotational movement between the fixed and movable pulley sheave halves as a result of changes of the force applied to the movable pulley sheave half during driving operation of the pulley. The rearrangement structure effectively minimizes vibration and noise by providing improved uniformity in the distribution of the force applying elements both in the steady state and speed and force changing conditions of the pulley.

Claims

1. A variable speed pulley comprising:

a first sheave half;

means for fixedly mounting the first sheave half on a rotatable shaft defining an axis of rotation;

a second sheave half;

means for coaxially movably mounting said second sheave half on said shaft adjacent said first sheave half to define a belt receiving groove therebetween;

biasing means for biasing said second sheave half axially of the shaft to vary the width of said belt receiving groove; and

urging means for urging said second sheave half axially of the shaft against the biasing force of said biasing means with a force proportional to the speed of rotation of said shaft to vary the width of said belt receiving groove, said urging means comprising

means movable with said second sheave half defining a fixed surface,

means fixedly associated with said shaft defining a fixed surface,

force applying means extending between said movable surface and said movable surface and having a variable extension parallel to said shaft axis proportional to the centrifugal force acting thereon as a result of said speed of rotation of the shaft, and

rearrangement means for varying the arrangement of said force applying means as an incident of a relative movement between said first and second sheave halves angularly about said axis of rotation.

2. The variable speed pulley of claim 1 wherein said means for biasing said second sheave half comprises means for biasing said second sheave half toward said first sheave half to reduce the width of said belt receiving groove, and said means for urging said second sheave half axially of the shaft comprises means for urging said second sheave half away from said first sheave half to increase the width of said belt receiving groove.

3. The variable speed pulley of claim 1 wherein said force applying means comprises a plurality of small discrete elements.

4. The variable speed pulley of claim 1 wherein said force applying means comprises a plurality of small spherical elements having a friction-reducing coating.

5. The variable speed pulley of claim 1 wherein said rearrangement means comprises spring means for permitting resilient rotational repositioning of said second sheave half on said shaft.

6. The variable speed pulley of claim 1 wherein said rearrangement means comprises spring means for permitting

resilient rotational repositioning of said second sheave half on said shaft as a result of a change in force applied to said second sheave half by a belt in said groove.

7. A variable speed pulley comprising:

a stationary pulley sheave half mounted fixedly to a shaft;

a movable pulley sheave half mounted for rotative and axial movement on the shaft adjacent said stationary pulley sheave half and defining therewith a belt receiving groove;

wall means fixedly mounted to the shaft, said wall means and movable pulley sheave half defining therebetween a chamber;

small spheres in said chamber; and

means for causing said sheave halves to impart distributing forces to said spheres as an incident of rotative movement of said movable sheave half on the shaft.

8. The variable speed pulley of claim 7 wherein said means for causing said sheave halves to impart distributing forces comprises spring means disposed radially inwardly of said chamber.

9. The variable speed pulley of claim 7 wherein said chamber comprises an annular chamber disposed coaxially of the shaft.

10. The variable speed pulley of claim 7 wherein said means for causing said sheave halves to impart distributing forces comprises a helical spring coaxial of the shaft and having opposite ends fixed to said fixed and movable pulley sheave halves respectively.

11. A variable speed pulley comprising:

a first sheave half;

means for fixedly mounting the first sheave half on a rotatable shaft defining an axis of rotation;

a second sheave half;

means for coaxially movably mounting said second sheave half on said shaft adjacent said first sheave half to define a belt receiving groove therebetween;

biasing means for biasing said second sheave half axially of the shaft to vary the width of said belt receiving groove; and

urging means for urging said second sheave half axially of the shaft against the biasing force of said biasing means with a force proportional to the speed of rotation of said shaft to vary the width of said belt receiving groove,

said urging means comprising

means movable with said second sheave half defining a movable surface,

means fixedly associated with said shaft defining a fixed surface and defining with said movable surface a variable volume space,

a plurality of small rounded elements disposed in said space between said movable surface and said fixed surface and having a variable extension parallel to said shaft axis proportional to the centrifugal force acting thereon as a result of said speed of rotation of the shaft, and

spring means for varying the arrangement of said force applying means as an incident of a relative movement between said first and second sheave halves about said axis of rotation.

12. The variable speed pulley of claim 11 wherein said plurality of rounded elements occupies substantially 80% of said variable volume space when said space defines its minimum volume.

13. The variable speed pulley of claim 11 wherein said space comprises an annular space having an isosceles triangular cross section at its minimum volume.

14. The variable speed pulley of claim 11 wherein all of said rounded elements are similar in shape.

15. The variable speed pulley of claim 11 wherein said rounded elements have different shapes.

16. The variable speed pulley of claim 11 wherein lubricating means is provided for lubricating said rounded elements.

17. The variable speed pulley of claim 11 wherein said rounded elements are formed of metal.

18. The variable speed pulley of claim 11 wherein said space comprises an annular space having a trapezoidal cross section at greater than minimum volume thereof.

19. The variable speed pulley of claim 11 wherein said surfaces defining said space comprise planar surfaces.

20. The variable speed pulley of claim 11 wherein said rounded elements are spherical and have a diameter in the range of approximately 11 to 6 mm.

21. The variable speed pulley of claim 11 wherein said rounded elements are spherical and have a diameter in the range of approximately 2 to 4 mm.

22. The variable speed pulley of claim 11 wherein said rounded elements are provided with a coating for reducing friction therebetween.

23. The variable speed pulley of claim 11 wherein said means for biasing said second sheave half comprises means for biasing said second sheave half toward said first sheave half to reduce the width of said belt receiving groove, and said means for urging said second sheave half axially of the shaft comprises means for urging said second sheave half away from said first sheave half to increase the width of said belt receiving groove.