Controller of toroidal continuously variable transmission

Patent metadata

Field	Value
Publication number	US-10508735-B2
Application number	US-201616082586-A
Country	US
Kind code	B2
Filing date	Mar 7, 2016
Priority date	Mar 7, 2016
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

A controller of a toroidal continuously variable transmission comprises a position control unit which outputs a driving signal to a hydraulic actuator to control a roller position. The hydraulic actuator includes a biasing mechanism which forcibly keeps the roller position at a predetermined position in a case where the driving signal meets a predetermined condition. The position control unit is configured to perform a start-up control during start-up of the toroidal continuously variable transmission. During the start-up control, the position control unit is configured to output the driving signal to reciprocate a spool of the hydraulic actuator in a case where a temperature of hydraulic oil supplied to the hydraulic actuator is lower than a reference temperature, and output the driving signal which meets the predetermined condition in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature thereafter.

First claim

The invention claimed is:

1. A controller of a toroidal continuously variable transmission in which a transmission ratio is continuously changed depending on a roller position of a power roller, the controller comprising:
a hydraulic actuator which changes the roller position; and
a position control unit which outputs a driving signal to the hydraulic actuator to control the roller position,
wherein the hydraulic actuator includes a biasing mechanism which forcibly keeps the roller position at a predetermined position in a case where the driving signal meets a predetermined condition,
wherein the position control unit is configured to perform a start-up control during start-up of the toroidal continuously variable transmission, and
wherein during the start-up control, the position control unit is configured to
output the driving signal to reciprocate a spool of the hydraulic actuator in a case where a temperature of hydraulic oil supplied to the hydraulic actuator is lower than a reference temperature, and
output the driving signal which meets the predetermined condition to keep the roller position at the predetermined position in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature thereafter.

2. The controller of the toroidal continuously variable transmission according to claim 1 , further comprising:
a position estimation unit which estimates the roller position based on an output value of the driving signal,
wherein during start-up of the toroidal continuously variable transmission, the position control unit is configured to perform the start-up control before the position control unit performs a normal control in which an output value of the driving signal is derived based on a deviation between a command value of the roller position and an estimated value of the roller position which is estimated by the position estimation unit, and
wherein the position estimation unit is configured to set the predetermined position to an initial value of the estimated value, when the start-up control is terminated and the normal control is initiated.

3. The controller of the toroidal continuously variable transmission according to claim 2 ,
wherein during the start-up control, the position control unit is configured to continue to output the driving signal which meets the predetermined condition until a standby time required for the spool to reach the predetermined position passes, in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature after the position control unit output the driving signal to reciprocate the spool of the hydraulic actuator.

4. The controller of the toroidal continuously variable transmission according to claim 2 ,
wherein during the start-up control, the position control unit is configured to continue to output the driving signal which meets the predetermined condition until the temperature of the hydraulic oil becomes equal to or higher than a second reference temperature higher than the reference temperature, in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature after the position control unit output the driving signal to reciprocate the spool of the hydraulic actuator.

5. The controller of the toroidal continuously variable transmission according to claim 2 ,
wherein during the start-up control, the position control unit is configured to output a pulse signal as the driving signal in a case where the temperature of the hydraulic oil supplied to the hydraulic actuator is lower than the reference temperature, and to set a wave height of the pulse signal to a smaller value as the temperature of the hydraulic oil is higher.

6. The controller of the toroidal continuously variable transmission according to claim 2 ,
wherein the predetermined condition is a condition in which an output value of the driving signal is a zero value or a negative value, and
wherein the biasing mechanism is a safety mechanism which forcibly returns the roller position to a lower limit point, in a case where the driving signal meets the predetermined condition.

7. The controller of the toroidal continuously variable transmission according to claim 1 ,
wherein during the start-up control, the position control unit is configured to continue to output the driving signal which meets the predetermined condition until a standby time required for the spool to reach the predetermined position passes, in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature after the position control unit output the driving signal to reciprocate the spool of the hydraulic actuator.

8. The controller of the toroidal continuously variable transmission according to claim 7 ,
wherein during the start-up control, the position control unit is configured to continue to output the driving signal which meets the predetermined condition until the temperature of the hydraulic oil becomes equal to or higher than a second reference temperature higher than the reference temperature, in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature after the position control unit output the driving signal to reciprocate the spool of the hydraulic actuator.

9. The controller of the toroidal continuously variable transmission according to claim 7 ,
wherein during the start-up control, the position control unit is configured to output a pulse signal as the driving signal in a case where the temperature of the hydraulic oil supplied to the hydraulic actuator is lower than the reference temperature, and to set a wave height of the pulse signal to a smaller value as the temperature of the hydraulic oil is higher.

10. The controller of the toroidal continuously variable transmission according to claim 7 ,
wherein the predetermined condition is a condition in which an output value of the driving signal is a zero value or a negative value, and
wherein the biasing mechanism is a safety mechanism which forcibly returns the roller position to a lower limit point, in a case where the driving signal meets the predetermined condition.

11. The controller of the toroidal continuously variable transmission according to claim 1 ,
wherein during the start-up control, the position control unit is configured to continue to output the driving signal which meets the predetermined condition until the temperature of the hydraulic oil becomes equal to or higher than a second reference temperature higher than the reference temperature, in a case where the temperature of the hydraulic oil has become equal to or higher than the reference temperature after the position control unit output the driving signal to reciprocate the spool of the hydraulic actuator.

12. The controller of the toroidal continuously variable transmission according to claim 11 ,
wherein during the start-up control, the position control unit is configured to output a pulse signal as the driving signal in a case where the temperature of the hydraulic oil supplied to the hydraulic actuator is lower than the reference temperature, and to set a wave height of the pulse signal to a smaller value as the temperature of the hydraulic oil is higher.

13. The controller of the toroidal continuously variable transmission according to claim 11 ,
wherein the predetermined condition is a condition in which an output value of the driving signal is a zero value or a negative value, and
wherein the biasing mechanism is a safety mechanism which forcibly returns the roller position to a l

Assignees

• Kawasaki Heavy Ind Ltd

Inventors

• Nakashima Kenichi
• Goi Tatsuhiko
• Watanabe Koji

Classifications

• F16H61/0213 Primary

  characterised by the method for generating shift signals · CPC title

• B60W10/06

  including control of combustion engines · CPC title

• F16H61/0267 Primary

  Layout of hydraulic control circuits, e.g. arrangement of valves · CPC title

• F16H61/02

  characterised by the signals used · CPC title

• B60W20/30

  Control strategies involving selection of transmission gear ratio {(control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H)} · CPC title