Continuously variable transmission apparatus

• US 6,991,575 B2
• Filed: 02/13/2004
• Issued: 01/31/2006
• Est. Priority Date: 02/14/2003
• Status: Expired due to Fees

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Inoue, Eiji
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US10/777,970
• Publication Number:
  US 20040204283A1
• Time in Patent Office: 718 Days
• Field of Search: 475/216, 475/208
• US Class Current: 475/216
• CPC Class Codes: F16H 2037/0886 with switching means, e.g. to change ranges
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member
• CPC Class Codes: F16H 61/12 Detecting malfunction or potential malfunction, e.g. fail safe in control of hydrostatic gearing F16H61/4192; Circumventing or fixing failures
• CPC Class Codes: F16H 61/6648 controlling of shifting being influenced by a signal derived from the engine and the main coupling

Abstract

A continuously variable transmission apparatus having input and output shafts, a toroidal-type continuously variable transmission unit (CVT unit), a gear-type differential unit with gears, and a control unit, the CVT unit has; input and output side disks, power rollers, input and output side rotation sensors, wherein the differential unit has; a first input portion and a second input portion, and wherein the control unit regulates the transmission ratio of the CVT unit so as to change relative displacement speeds of the gears of the differential unit to thereby convert the rotational state of the output shaft to forward and backward rotations with a stationary state being interposed therebetween, with the input shaft being kept rotating in one direction, and to calculate a rotational speed of the output shaft based on rotational speeds of the input and output side disks and a gear ratio of the differential unit.

Claims

1. A continuously variable transmission apparatus having an input shaft, an output shaft, a toroidal-type continuously variable transmission unit, a gear-type differential unit in combination with a plurality of gears, and a control unit for controlling a change in transmission ratio of the toroidal-type continuously variable transmission unit, wherein

the toroidal-type continuously variable transmission unit has;

an input side disk rotatably driven by the input shaft,

an output side disk supported coaxially with the input side disk and rotatably relative to the input side disk,

a plurality of power rollers interposed between the input side disk and the output side disk,

an input side rotation sensor for measuring a rotational speed of the input side disk, and

an output side rotation sensor for measuring a rotational speed of the output side disk,

wherein the differential unit has;

a first input portion rotated together with the input side disk by the input shaft, and

a second input portion connected to the output side disk, whereby a rotation according to a difference in speed between the first and second input portions is taken to be transmitted to the output shaft, and

wherein the control unit regulates the transmission ratio of the toroidal-type continuously variable transmission unit so as to change relative speeds of the plurality of gears constituting the differential unit to thereby convert the rotational state of the output shaft to forward and backward rotations with a stationary state being interposed therebetween, with the input shaft being kept rotating in one direction, and to calculate a rotational speed of the output shaft based on a rotational speed of the input side disk obtained by the input side rotation sensor and a rotational speed of the output side disk obtained by the output side rotation sensor, and a gear ratio of the differential unit.

2. A continuously variable transmission apparatus as set forth in claim 1, wherein the control unit further regulates a torque which passes through the toroidal-type continuously variable transmission unit to be transmitted to the output shaft according to the rotational speed of the output shaft so calculated by changing the transmission ratio of the toroidal-type continuously variable transmission unit.