Continuously variable transmission

• US 9,291,251 B2
• Filed: 11/14/2014
• Issued: 03/22/2016
• Est. Priority Date: 11/10/2010
• Status: Active Grant

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Inventors: Lohr, Charles B., Pohl, Brad P.
• Primary Examiner(s): LEWIS, TISHA D
• Application Number:
  US14/541,875
• Publication Number:
  US 20150072827A1
• Time in Patent Office: 494 Days
• US Class Current: 1/1
• CPC Class Codes: B62M 11/16 built in, or adjacent to, the ground-wheel hub
• CPC Class Codes: F16C 19/545 Systems comprising at least one rolling bearing for radial load in combination with at least one rolling bearing for axial load
• CPC Class Codes: F16H 15/50 Gearings providing a continuous range of gear ratios
• CPC Class Codes: F16H 15/503 in which two members co-operate by means of balls or rollers of uniform effective diameter, not mounted on shafts
• CPC Class Codes: F16H 15/52 in which a member of uniform effective diameter mounted on a shaft may co-operate with different parts of another member
• CPC Class Codes: F16H 2057/085 Bearings for orbital gears
• CPC Class Codes: F16H 55/32 Friction members
• CPC Class Codes: F16H 57/0484 with variable gear ratio or for reversing rotary motion
• CPC Class Codes: F16H 57/0487 Friction gearings

Abstract

Components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT) are provided. In one embodiment, a CVT has a number of spherical planets in contact with an idler assembly. Various idler assemblies can be used to facilitate to improve durability, fatigue life, and efficiency of a CVT. In one embodiment, the idler assembly has two rolling elements having contact surfaces that are angled with respect to a longitudinal axis of the CVT. In some embodiments, a bearing is operably coupled between the first and second rolling elements. The bearing is configured to balance axial force between the first and second rolling elements. In one embodiment, the bearing is a ball bearing. In another embodiment, the bearing is an angular contact bearing. In yet other embodiments, needle roller bearings are employed.

Claims

1. An idler assembly for a continuously variable transmission (CVT) having a plurality of tiltable traction planet assemblies arranged about a longitudinal axis, each traction planet assembly operably coupled to a carrier having a plurality of radially offset guide slots, the idler assembly comprising:

a first rolling element rotatable about an axis at a first speed corresponding to a tilt angle of a planet axle relative to the longitudinal axis;

a second rolling element rotatable about the axis at a second speed corresponding to the tilt angle of a planet axle relative to the longitudinal axis, each of the first rolling element and the second rolling element comprising first and second surfaces angled for contact with a traction planet, the first surface angled at a first angle and the second surface angled less than the first angle;

a first bearing interposed between the first rolling element and the second rolling element; and

a second bearing coupled to a shoulder of the first rolling element, wherein the second rolling element is axially coupled to the first rolling element with the second bearing.

2. The idler assembly of claim 1, wherein the first angle is in the range between 0 and 45 degrees.

3. The idler assembly of claim 2, wherein the first angle is in the range between 0 and 10 degrees.

4. A continuously variable transmission (CVT) comprising:

a plurality of tiltable traction planet assemblies arranged about a longitudinal axis, each tiltable traction planet assembly rotatable around an axle;

a pair of carriers, each carrier having a plurality of guide slots, wherein each axle of the plurality of tiltable traction planet assemblies is coupled to the pair of carriers, wherein rotation of at least one of the pair of carriers causes a tilt in the plurality of tillable traction planet assemblies; and

an idler assembly comprising

a first rolling element rotatable about an axis at a first speed corresponding to a tilt angle of a planet axle relative to the longitudinal axis,

a second rolling element rotatable about the axis at a second speed corresponding to the tilt angle of a planet axle relative to the longitudinal axis, each of the first rolling element and the second rolling element comprising first and second surfaces angled for contact with the plurality of traction planet assemblies, the first surface angled at a first angle and the second surface angled less than the first angle, and

a first bearing interposed between the first rolling element and the second rolling element, the first bearing positioned radially inward of the second rolling element.

5. The continuously variable transmission (CVT) of claim 4, wherein the first angle is in the range between 0 and 45 degrees.

6. The continuously variable transmission (CVT) of claim 5, wherein the first angle is in the range between 0 and 10 degrees.

7. The continuously variable transmission (CVT) of claim 4, further comprising a second bearing, the second bearing positioned axially between at least a portion of the first rolling element and at least a portion of the second rolling element.