Straddle-type vehicle

• US 8,535,186 B2
• Filed: 08/30/2007
• Issued: 09/17/2013
• 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)
• Inventors: Asaoka, Ryousuke
• Primary Examiner(s): Rivera, William A
• Assistant Examiner(s): LIU, HENRY Y
• Application Number:
  US11/848,072
• Publication Number:
  US 20080053731A1
• Time in Patent Office: 2,210 Days
• Field of Search: 474/11, 474/12, 474/18, 474/28, 474/33, 474/45, 474/46, 474/48, 474/69, 474/70, 474/72, 477/39, 477/41, 477/44, 477/45, 477/48, 477/69, 701/51, 701/60, 701/61, 701/62
• US Class Current: 474/28
• 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, comprising:

an actuator;

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 the actuator, and the moving flange of the secondary sheave is biased in a direction to narrow the groove width; and

a control unit connected to the actuator, wherein the control unit

determines whether a gear change is upshift or downshift, and

controls an output of the actuator in such a manner so as to change the output of the actuator according to a sheave slide resistance at upshift when the gear change is upshift, and

controls the output of the actuator in such a manner so as to change the output of the actuator according to a sheave slide resistance at downshift when the gear change is downshift.

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. The belt type continuously variable transmission of claim 1, further including a storage unit, wherein the control unit reads a value from a map stored in the storage unit, the value corresponding to an actual flange position sensed by a sheave position sensor, and calculates a manipulation amount of the actuator in consideration of the sheave slide resistance at the actual flange position based at least partly on the value read from the map.

8. The continuously variable transmission according to claim 1, wherein the control unit determines a target speed change ratio and determines whether the gear change to the target speed ratio is upshift or downshift.

9. The continuously variable transmission according to claim 1, wherein the sheave slide resistance at downshift is lower than the sheave slide resistance at upshift.

10. A belt type continuously variable transmission, comprising:

an actuator;

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 the actuator, and the moving flange of the secondary sheave is biased in a direction to narrow the groove width;

a sheave-position sensor that senses a position of the moving flange of the primary sheave; and

a control unit connected to the actuator and to the sheave-position sensor, wherein the control unit

determines whether a gear change is upshift or downshift, and

controls an output of the actuator in such a manner so as to change the output of the actuator according to a sheave slide resistance at upshift corresponding to the moving flange position sensed by the sheave-position sensor when the gear change is upshift, and

controls the output of the actuator in such a manner so as to change the output of the actuator according to a sheave slide resistance at downshift corresponding to the moving flange position sensed by the sheave-position sensor when the gear change is downshift.

11. The continuously variable transmission according to claim 10, wherein the output of the actuator is larger in Low than in Top.

12. The continuously variable transmission according to claim 10, 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.

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

the actuator is an electric motor;

and

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

14. The continuously variable transmission according to claim 13, wherein the electric power supplied to the electric motor is controlled by a duty ratio of a pulse signal output from the control unit.

15. A straddle-type vehicle comprising the continuously variable transmission according to claim 10.

16. The belt type continuously variable transmission of claim 10, further including a storage unit, wherein the control unit reads a value from a map stored in the storage unit, the value corresponding to the moving flange position, and calculates a manipulation amount of the actuator in consideration of the sheave slide resistance at the moving flange position based at least partly on the value read from the map.

17. The continuously variable transmission according to claim 10, wherein the control unit determines a target speed change ratio and determines whether the gear change to the target speed ratio is upshift or downshift.

18. The continuously variable transmission according to claim 10, wherein the sheave slide resistance at downshift is lower than the sheave slide resistance at upshift.