Pulley for a continuously variable transmission

Patent metadata

Field	Value
Publication number	US-10767745-B2
Application number	US-201815871459-A
Country	US
Kind code	B2
Filing date	Jan 15, 2018
Priority date	Jan 16, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A pulley for a CVT has a fixed sheave, a movable sheave, a spider, a biasing member biasing the movable sheave axially away from the fixed sheave, at least one centrifugal actuator and at least one roller assembly. The at least one centrifugal actuator has an arm pivotally connected to one of the movable sheave and the spider. The arm has a thrust portion pushing against a track portion of a roller of the at least one roller assembly upon rotation of the CVT, the roller being rotationally connected to another one of the movable sheave and the spider. The roller receives the thrust portion of the arm on the track portion thereof such that the thrust portion of the arm remains in contact with the track portion of the roller. The arm and the roller thereby transfer axial and rotational forces between the spider and the movable sheave.

First claim

What is claimed is:

1. A pulley for a continuously variable transmission comprising:
a fixed sheave having an axis of rotation;
a movable sheave axially movable relative to the fixed sheave;
a spider axially fixed relative to the fixed sheave and rotationally fixed relative to the movable sheave, the movable sheave being disposed axially between the spider and the fixed sheave;
a biasing member biasing the movable sheave axially away from the fixed sheave;
at least one centrifugal actuator comprising an arm pivotally connected to one of the movable sheave and the spider, the arm pivoting away from the one of the movable sheave and the spider as a speed of rotation of the pulley increases, the arm having a thrust portion, the arm having a first outer profile at the thrust portion; and
at least one roller assembly comprising a roller rotationally connected to another one of the movable sheave and the spider, the roller having a track portion having a second outer profile complementary to the first outer profile, the thrust portion of the arm of the at least one centrifugal actuator pushing against the track portion of the roller of the at least one roller assembly as the arm pivots away from the one of the movable sheave and the spider, thereby moving the movable sheave axially toward the fixed sheave, the roller receiving the thrust portion of the arm on the track portion such that the thrust portion of the arm remains in contact with the track portion of the roller, the arm and the roller thereby transferring axial and rotational forces between the spider and the movable sheave, a cross section of the first outer profile of the thrust portion of the arm, taken along a first plane parallel to a pivot axis of the arm, being convex, and a cross section of the second outer profile of the track portion of the roller, taken along a second plane containing a rotation axis of the roller, being concave.

2. The pulley of claim 1 , wherein the thrust portion of the arm has at least one contact point with the track portion of the roller.

3. The pulley of claim 2 , wherein the thrust portion of the arm has two contact points with the track portion of the roller.

4. The pulley of claim 1 , wherein the thrust portion of the arm remains generally centered on the track portion of the roller.

5. The pulley of claim 1 , wherein:
the cross section of the first outer profile of the thrust portion of the arm, taken along the first plane parallel to the pivot axis of the arm, has a generally parabolic shape; and
the cross section of the second outer profile of the track portion of the roller, taken along the second plane containing the rotation axis of the roller, has a generally parabolic shape.

6. The pulley of claim 1 , wherein each of the at least one roller assembly further comprises an axle extending through the roller for connecting the at least one roller assembly to the other one of the moveable sheave and the spider.

7. The pulley of claim 6 , wherein for each of the at least one roller assembly:
the axle is a hollow axle having a threaded inner portion; and
at least one screw engages the threaded inner portion of the axle for connecting the axle to the other one of the moveable sheave and the spider.

8. The pulley of claim 6 , wherein for each of the at least one roller assembly:
the axle has a threaded outer portion; and
a nut engages the threaded outer portion of the axle for connecting the axle to the other one of the moveable sheave and the spider.

9. The pulley of claim 1 , wherein the arm comprises a hollow cylindrical portion perpendicularly connected to the thrust portion.

10. The pulley of claim 9 , further comprising a pin extending through the hollow cylindrical portion of the arm for pivotally connecting the arm to the one of the moveable sheave and the spider.

11. The pulley of claim 1 , wherein the thrust portion of the arm is longitudinally curved.

12. The pulley of claim 1 , wherein the thrust portion has an end portion engaging the track portion of the roller when the arm is fully pivoted away from the one of the movable sheave and the spider.

13. The pulley of claim 12 , wherein the spider defines an aperture, and the end portion of the arm extends through the aperture at least when the movable sheave is fully axially moved away from the fixed sheave.

14. The pulley of claim 1 , further comprising a damper connecting the fixed sheave to the spider and transferring the rotational forces between the fixed sheave and the spider.

15. The pulley of claim 1 , wherein the arm is pivotally connected to the movable sheave, and the roller is rotationally connected to the spider.

16. The pulley of claim 1 , wherein:
the at least one centrifugal actuator is three centrifugal actuators disposed at 120 degrees from each other;
the at least one roller assembly is three roller assemblies disposed at 120 degrees from each other; and
each of the three centrifugal actuators is aligned with a corresponding one of the three roller assemblies.

17. The pulley of claim 1 , further comprising:
a fixed sheave shaft connected to the fixed sheave; and
a movable sheave shaft connected to the movable sheave, the fixed sheave shaft being disposed at least in part inside the movable sheave shaft;
wherein the movable sheave shaft is disposed at least in part inside the biasing member; and
wherein the biasing member is disposed at least in part inside the spider.

18. A continuously variable transmission comprising:
the pulley according to claim 1 , the pulley being a primary pulley;
a secondary pulley having:
a fixed sheave; and
a movable sheave axially movable relative to the fixed sheave; and

a drive belt looped around the fixed and movable sheaves.

19. A vehicle comprising:
a frame;
a motor connected to the frame;
the continuously variable transmission of claim 18 , the primary pulley being operatively connected to and driven by the motor;
a driven shaft connected to and driven by the secondary pulley; and
at least one ground engaging member operatively connected to the driven shaft.

Assignees

• Brp Rotax Gmbh & Co Kg

Inventors

• Zauner Gunther
• Schneck Thomas

Classifications

• F16H55/56

  of which the bearing parts are relatively axially adjustable · CPC title

• F16H9/18

  only one flange of each pulley being adjustable · CPC title

• F16H55/563 Primary

  actuated by centrifugal masses · CPC title

• B62M27/02

  power driven · CPC title