Continuously variable transmission

Patent metadata

Field	Value
Publication number	US-9574642-B2
Application number	US-201414519672-A
Country	US
Kind code	B2
Filing date	Oct 21, 2014
Priority date	Oct 14, 2008
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable accessory drives (CVAD). In one embodiment, a skew-based control system is adapted to facilitate a change in the ratio of a CVAD. In another embodiment, a skew-based control system includes a skew actuator coupled to a carrier member. In some embodiments, the skew actuator is configured to rotate a carrier member of a CVT. Various inventive traction planet assemblies can be used to facilitate shifting the ratio of a CVT. In some embodiments, the traction planet assemblies include legs configured to cooperate with the carrier members. In some embodiments, a traction planet assembly is operably coupled to the carrier members. Embodiments of a shift cam and traction sun are adapted to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces for a CVT are disclosed.

First claim

What we claim is:

1. A method for controlling a continuously variable accessory drive (CVAD) with a continuously variable transmission (CVT) coupled to a prime mover and a load, the CVT having a plurality of traction planets, each traction planet adapted to rotate about a tiltable axis, the method comprising:
a) receiving a desired tilt angle set point for the plurality of traction planets in the CVT;
b) determining a command signal for a skew actuator, the skew actuator comprising a hydraulic piston coupled to the CVAD, the hydraulic piston operably coupled to a first carrier member of the CVAD, the first carrier member comprising a plurality of radially offset slots formed in the first carrier member and arranged angularly about a longitudinal axis of the CVAD;
c) applying the command signal to the skew actuator, wherein applying the command signal to the skew actuator causes the first carrier member to rotate about the longitudinal axis to apply a skew condition to tilt the axes of the plurality of traction planets;
d) measuring the tilt angle for the plurality of traction planets in the CVT;
e) comparing the measured tilt angle to the desired tilt angle; and
f) repeating step b) through step e) until the measured tilt angle is substantially equal to the desired tilt angle.

2. The method of claim 1 , wherein applying the command signal to the skew actuator applies a relative motion between the first carrier member and a second carrier member of the CVAD.

3. The method of claim 1 , wherein measuring the tilt angle for the plurality of traction planets comprises using a proximity sensor.

4. A continuously variable transmission (CVT) system for use in a continuously variable accessory drive (CVAD), comprising:
an input driver for receiving power from an input shaft coupled to an external source;
a first traction ring coupled to the input driver for receiving power;
a variator assembly coupled to the first traction ring for receiving power from the first traction ring, the variator assembly;
a second traction ring coupled to the variator assembly for receiving power from the variator assembly;
a planetary gear assembly coupled to the second traction ring and further coupled to an output shaft; and
a controller operable to:
a) receive a desired tilt angle for a plurality of traction planet assemblies in the CVT;
b) determine a command signal for a skew actuator, the skew actuator comprising a hydraulic piston coupled to the CVAD, the hydraulic piston operably coupled to a first carrier member of the CVAD, the first carrier member comprising a plurality of radially offset slots formed in the first carrier member and arranged angularly about a longitudinal axis of the CVAD;
c) apply the command signal to the skew actuator, wherein applying the command signal to the skew actuator causes the first carrier member to rotate about the longitudinal axis to apply a skew condition to tilt the axes of the plurality of traction planet assemblies;
d) measure the tilt angle for the plurality of traction planet assemblies in the CVT;
e) compare the measured tilt angle to the desired tilt angle; and
f) repeat step b) through step e) until the measured tilt angle is substantially equal to the desired tilt angle.

5. The CVT system of claim 4 , wherein the output shaft is coupled to a ring gear of the planetary gear assembly.

6. The CVT system of claim 4 , wherein a planetary sun driver is coupled to a sun gear of the planetary gear assembly.

7. The CVT system of claim 6 , wherein an axial force generator is coupled to the second traction ring and further coupled to the planetary sun driver.

8. The CVT system of claim 4 , wherein the skew actuator comprises a servo motor.

9. The CVT system of claim 4 , wherein the skew actuator comprises an electro-hydraulic actuator.

Assignees

• Fallbrook Ip Co Llc

Inventors

• Pohl Brad P
• Thomassy Fernand A
• Lohr Charles B
• Mcbroom Scott T

Classifications

• F16H15/42

  in which two members co-operate by means of rings or by means of parts of endless flexible members pressed between the first mentioned members · CPC title

• F16H15/50

  Gearings providing a continuous range of gear ratios · CPC title

• Y02T10/76

  Cross-Sectional Technologies · mapped topic

• F16H15/503 Primary

  in which two members co-operate by means of balls or rollers of uniform effective diameter, not mounted on shafts · CPC title

• Y10T477/619

  Cross-Sectional Technologies · mapped topic