Method of controlling clamping of wedge-actuated CVT and powertrain with wedge-actuated CVT

Patent metadata

Field	Value
Publication number	US-10473213-B2
Application number	US-201715829294-A
Country	US
Kind code	B2
Filing date	Dec 1, 2017
Priority date	Dec 1, 2017
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A method of controlling a continuously variable transmission includes monitoring powertrain operating conditions, and calculating, via an electronic controller, a commanded clamping force based on the powertrain operating conditions, wherein the commanded clamping force includes a commanded clamping force of an input pulley and a commanded clamping force of an output pulley on the endless rotatable device. The method also includes activating, via the electronic controller, at least one of the input actuator and the output actuator such that an axial component of the input wedge force and the axial force of the input actuator together provide the commanded clamping force of the input pulley, and an axial component of the output wedge force and the axial force of the output actuator together provide the commanded clamping force of the output pulley.

First claim

The invention claimed is:

1. A method of controlling a continuously variable transmission (CVT) included in a powertrain; wherein the CVT includes:
an input wedge component mounted on an input shaft, wherein the input wedge component is configured to provide an input wedge force on an input movable sheave of an input pulley when a direction of drive torque on the input shaft is in a forward drive direction;
an output wedge component mounted on an output shaft, wherein the output wedge component is configured to provide an output wedge force on an output movable sheave of an output pulley when a direction of load torque on the output shaft is opposite to the forward drive direction, the output pulley connected with the input pulley via an endless rotatable device;
an input actuator operable to provide an axial force on the input movable sheave; and
an output actuator operable to provide an axial force on the output movable sheave;
the method comprising:
monitoring powertrain operating conditions;
calculating, via an electronic controller, a commanded clamping force based on the powertrain operating conditions, wherein the commanded clamping force includes a commanded clamping force of the input pulley on the endless rotatable device, and a commanded clamping force of the output pulley on the endless rotatable device;
calculating an axial component of the input wedge force of the input wedge component based on estimated drive torque on the input shaft, an angle of a wedge surface of the input wedge component that interfaces with the input movable sheave, an angle of a pulley surface of the input movable sheave, and an outer radius of the input wedge component; and
activating, via the electronic controller, at least one of the input actuator and the output actuator such that the axial component of the input wedge force and the axial force of the input actuator together provide the commanded clamping force of the input pulley, and an axial component of the output wedge force and the axial force of the output actuator together provide the commanded clamping force of the output pulley.

2. The method of claim 1 , wherein the powertrain includes an engine operable to provide drive torque on the input shaft, and an electric machine operatively connected to the engine; and
wherein monitoring powertrain operating conditions includes monitoring at least one of engine torque and a mode of operation of the electric machine.

3. The method of claim 2 , wherein the powertrain includes a gearing arrangement connected between the engine and the input shaft and operable to reverse a direction of drive torque on the input shaft during a reverse operating mode; and
wherein monitoring powertrain operating conditions includes monitoring the direction of the drive torque on the input shaft.

4. The method of claim 1 , wherein monitoring powertrain operating conditions includes monitoring a position of a gear shift lever.

5. The method of claim 1 , wherein monitoring powertrain operating conditions includes monitoring a braking and deceleration of a vehicle propelled by the powertrain.

6. The method of claim 1 , wherein the input wedge force is measured via a force sensor mounted on the wedge surface of the input wedge component that interfaces with the input movable sheave of the input pulley.

7. The method of claim 1 , wherein the angle of the wedge surface varies along a length of the wedge surface; and
wherein activating the at least one of the input actuator and the output actuator includes positioning differently angled portions of the wedge surface against a ramp surface of the movable input sheave to control the axial component of the input wedge force.

8. The method of claim 1 , wherein monitoring powertrain operating conditions includes monitoring one or more of torque on the input shaft, torque on the output shaft, rotational speed of the input shaft, rotational speed of the output shaft, position of the endless rotatable device on the input pulley, position of the endless rotatable device on the output pulley, and transmission slip.

9. The method of claim 1 , wherein at least one of the input actuator and the output actuator is a hydraulic actuator; and further comprising:
monitoring hydraulic pressure supplied to the hydraulic actuator.

10. The method of claim 1 , wherein at least one of the input actuator and the output actuator is an electric linear screw; and further comprising:
adjusting a position of the linear screw.

11. A powertrain comprising:
a continuously variable transmission (CVT) that includes:
an input wedge component mounted on an input shaft; wherein the input wedge component is configured to provide an input wedge force on an input movable sheave of an input pulley when a direction of drive torque on the input shaft is in a forward drive direction;
an output wedge component mounted on an output shaft; wherein the output wedge component is configured to provide an output wedge force on an output movable sheave of an output pulley when a direction of load torque on the output shaft is opposite to the forward drive direction, the output pulley connected with the input pulley via an endless rotatable device;
an input actuator operable to provide an axial force on the input movable sheave; and
an output actuator operable to provide an axial force on the output movable sheave; and

an electronic controller operatively connected to the CVT and configured to:
monitor powertrain operating conditions;
calculate a commanded clamping force based on the powertrain operating conditions; wherein the commanded clamping force includes a commanded clamping force of the input pulley on the endless rotatable device, and a commanded clamping force of the output pulley on the endless rotatable device;
calculate an axial component of the input wedge force of the input wedge component based on estimated drive torque on the input shaft, an angle of a wedge surface of the input wedge component that interfaces with the input movable sheave, an angle of a pulley surface of the input movable sheave, and an outer radius of the input wedge component; and
activate at least one of the input actuator and the output actuator such that the axial component of the input wedge force and the axial force of the input actuator together provide the commanded clamping force of the input pulley, and an axial component of the output wedge force and the axial force of the output actuator together provide the commanded clamping force of the output pulley.

12. The powertrain of claim 11 , wherein:
the powertrain includes an engine operable to provide drive torque on the input shaft, and an electric machine operatively connected to the engine; and
the powertrain operating conditions monitored by the controller include at least one of engine torque and a mode of operation of the electric machine as a generator during engine braking.

13. The powertrain of claim 12 , wherein:
the powertrain includes a gearing arrangement connected between the engine and the input shaft and operable to reverse the direction of drive torque on the input shaft during a reverse operating mode; and
the powertrain operating conditions monitored by the controller include the direction of drive torque on the input shaft.

14. The powertrain of claim 11 , wherein:
the powertrain includes a gear shift lever; and
the powertrain operating conditions monitored by the controller include a position of the gear shift lever.

15. The powertrain of claim 11 , further comprising:
a force sensor mounted on the wedge surface of the input wedge component that inte

Assignees

• Gm Global Tech Operations Llc

Inventors

• Huang Ying
• Lee Chunhao J
• Yao Jian
• Duan Chengwu

Classifications

• F16H2059/183

  Rate of change of accelerator position, i.e. pedal or throttle change gradient · CPC title

• F16H63/065

  hydraulic actuating means · CPC title

• F16H63/062

  electric or electro-mechanical actuating means · CPC title

• B60W10/107

  with endless flexible members · CPC title

• B60K6/543

  the transmission being a continuously variable transmission · CPC title