Straddle-Type Vehicle

• US 20080053731A1
• Filed: 08/30/2007
• Published: 03/06/2008
• Est. Priority Date: 09/01/2006
• Status: Active Grant

• Current Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation)
• Original Assignee: Yamaha Hatsudoki Kabushiki Kaisha (Yamaha Corporation), Yamaha Motor Company Limited (Yamaha Corporation)
• Inventors: ASAOKA, Ryousuke
• Granted Patent: US 8,535,186 B2
• Time in Patent Office: Days
• US Class Current: 180/220
• CPC Class Codes: F16H 61/66259 using electrical or electronical sensing or control means

Abstract

A continuously variable transmission configured to reduce response delay and hunting due to overshooting. The continuously variable transmission is electronically controlled by a control unit. The control unit is connected to an actuator for moving a moving flange of a primary sheave and controls the output of the actuator in such a manner as to vary between upshift and downshift of the continuously variable transmission.

Claims

1. A belt type continuously variable transmission electronically controlled by a control unit, comprising:

a primary sheave and a secondary sheave each having a V-groove and a belt wound around the V-grooves of the sheaves, wherein groove widths of the sheaves are varied to control a speed change ratio steplessly, wherein

the primary sheave and the secondary sheave each have a fixed flange and a moving flange mounted on a rotation shaft;

the groove width of the primary sheave is adjusted by controlling movement of the moving flange of the primary sheave by an actuator, and the moving flange of the secondary sheave is biased in a direction to narrow the groove width;

the actuator is connected to the control unit; and

the control unit controls output of the actuator in such a manner as to change the output of the actuator between upshift and downshift of the continuously variable transmission.

2. The continuously variable transmission according to claim 1, wherein the output of the actuator is larger for upshift than for downshift.

3. The continuously variable transmission according to claim 1, further comprising:

a storage unit connected to the control unit that stores specified relative moduli corresponding to moving flange positions of the primary sheave,

wherein the output of the actuator is controlled according to an actuator manipulation amount calculated by multiplying a command value to the actuator by a relative modulus.

4. The continuously variable transmission according to claim 1, wherein

the actuator is an electric motor;

and

the output of the electric motor is controlled by electric power supplied to the electric motor.

5. The continuously variable transmission according to claim 4, wherein the electric power supplied to the electric motor is controlled by a duty ratio of a pulse signal output from the control unit.

6. A straddle-type vehicle comprising the continuously variable transmission according to claim 1.

7. A belt type continuously variable transmission electronically controlled by a control unit, comprising:

a primary sheave and a secondary sheave each having a V-groove and a belt wound around the V-grooves of the sheaves, wherein groove widths of the sheaves are varied to control a speed change ratio steplessly, wherein

the primary sheave and the secondary sheave each have a fixed flange and a moving flange mounted on a rotation shaft;

the groove width of the primary sheave is adjusted by controlling movement of the moving flange of the primary sheave by an actuator, and the moving flange of the secondary sheave is biased in a direction to narrow the groove width;

the actuator is connected to the control unit;

the control unit is connected to a sheave-position sensor that senses the position of the moving flange of the primary sheave; and

the control unit controls output of the actuator in such a manner as to change the output of the actuator according to the moving flange position sensed by the sheave-position sensor.

8. The continuously variable transmission according to claim 7, wherein the output of the actuator is larger in Low than in Top.

9. The continuously variable transmission according to claim 7, further comprising:

a storage unit connected to the control unit that stores specified relative moduli corresponding to moving flange positions of the primary sheave; and

the output of the actuator is controlled according to an actuator manipulation amount calculated by multiplying a command value to the actuator by a relative modulus.

10. The continuously variable transmission according to claim 7, wherein

the actuator is an electric motor;

and

the output of the electric motor is controlled by electric power supplied to the electric motor.

11. The continuously variable transmission according to claim 10, wherein the electric power supplied to the electric motor is controlled by a duty ratio of a pulse signal output from the control unit.

12. A straddle-type vehicle comprising the continuously variable transmission according to claim 7.

13. A method for reducing response delay and hunting in a continuously variable transmission comprising:

calculating a target speed change ratio;

calculating a target flange position of a moving flange of a primary sheave to achieve the target speed change ratio;

detecting an actual flange position of the moving flange;

calculating an actuator manipulation amount from deviation of the actual flange position from the target flange position, and from a relative modulus corresponding to a flange position;

converting the actuator manipulation amount to power that is supplied to an electric motor;

converting the power that is supplied to the electric motor to mechanical energy that moves the moving flange to the target flange position.

14. The method according to claim 13, wherein:

when a gear change is upshift, the relative modulus is read from an upshift modulus map, and when the gear change is downshift, the relative modulus is read from a downshift modulus map.

15. The method according to claim 13, wherein the relative modulus corresponds to the actual flange position.

16. The method according to claim 13, wherein the relative modulus corresponds to the target flange position.

17. The method according to claim 13, wherein the actuator manipulation amount is calculated by multiplying a command value determined from the deviation of the actual flange position from the target flange position by the relative modulus.

18. The method according to claim 17, wherein the command value for an upshift gear change is positive, and wherein the command value for a downshift gear change is negative.

19. The method according to claim 18, wherein the relative modulus is read from an upshift modulus map when the command value is positive, and wherein the relative modulus is read from a downshift modulus map when the command value is negative.

20. A control unit for a continuously variable transmission implementing the method of claim 13.