Control system for a toroidal continuously variable transmission

• US 6,045,481 A
• Filed: 03/09/1999
• Issued: 04/04/2000
• Est. Priority Date: 03/10/1998
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Kumagai, Tomoharu
• Primary Examiner(s): Marmor, Charles A.
• Assistant Examiner(s): PANG, ROGER L
• Application Number:
  US09/264,893
• Time in Patent Office: 392 Days
• Field of Search: 477/37, 701/60, 701/61, 476/41, 476/42
• US Class Current: 477/37
• CPC Class Codes: F16H 61/664 Friction gearings
• CPC Class Codes: F16H 61/6648 controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: F16H 61/6649 characterised by the means for controlling the torque transmitting capability of the gearing

Abstract

A control system for a toroidal continuously variable transmission which can control the transmission ratio without installing a position detection device or an angle detection device on trunnions and secure a sufficient control response to prevent hunting of the transmission ratio. To realize this control system, an axial force calculation device M3 calculates the axial force 2Ft in the trunnion axis direction that the transmission ratio control actuators are required to generate, based on the transmission ratio i calculated by a transmission ratio calculation device M1 from the input disk revolution speed ω₁ and the output disk revolution speed ω₂, and on the input torque Ti or output torque To estimated by a torque estimation device M2. An axial force change calculation device M4 calculates the amount of change in the axial force ΔFt based on the deviation between the target transmission ratio ic and the transmission ratio i. A target axial force calculation device M5 adds the axial force 2Ft to the amount of change in the axial force ΔFt to calculate the target axial force Fc. An actuator drive device M6 drives the actuators according to the target axial force Fc to match the transmission ratio i to the target transmission ratio ic.

Claims

1. A control system for a toroidal continuously variable transmission comprising:

an input disk and an output disk which are disposed opposed to each other,

power rollers which are in abutment against said input disk and said output disk to conduct transmission of a driving force between said input disk and said output disk,

trunnions for supporting said power rollers rotatably, said trunnions being supported displaceably in the direction of an axis of said trunnions, and tiltably about said axis,

an actuator for displacing said trunnions in the direction of said axis to tilt said power rollers together with said trunnions, and

a control means for driving said actuator to control a transmission ratio between said input disk and said output disk,

wherein said control means comprises;

an input rotation speed detection means for detecting a rotation speed of said input disk,

an output rotation speed detection means for detecting a rotation speed of said output disk,

a transmission ratio calculation means for calculating said transmission ratio from the input disk rotation speed and the output disk rotation speed,

a torque estimation means for estimating one an input torque of said input disk and an output torque of said output disk,

an axial force calculation means for calculating an axial force in the trunnion axis direction that said actuator is required to generate, based on the transmission ratio calculated by said transmission ratio calculation means and the torque estimated by said torque estimation means, and

an actuator drive means for driving said actuator based on the axial force calculated by said axial force calculation means.

2. A control system for a toroidal continuously variable transmission according to claim 1, wherein said control system further includes:

an axial force change amount calculation means for calculating an amount of change in the axial force based on a deviation between a target transmission ratio and the transmission ratio calculated by said transmission ratio calculation means, and a target axial force calculation means for calculating a target axial force based on the axial force calculated by said axial force calculation means and the amount of change in the axial force calculated by said axial force change amount calculation means, and wherein, based on the target axial force calculated by said target axial force calculation means, said actuator drive means drives the actuator to converge said deviation to zero.