Continuously variable transmission apparatus

• US 6,932,739 B2
• Filed: 12/23/2002
• Issued: 08/23/2005
• Est. Priority Date: 12/25/2001
• Status: Expired due to Fees

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Miyata, Shinji, Hashitani, Hideki
• Primary Examiner(s): PANG, ROGER L
• Application Number:
  US10/325,900
• Publication Number:
  US 20030125154A1
• Time in Patent Office: 974 Days
• Field of Search: 477/39, 477/40, 477/41, 475/208, 475/209, 475/214, 475/215, 475/216
• US Class Current: 477/41
• CPC Class Codes: F16H 2037/0886 with switching means, e.g. to change ranges
• CPC Class Codes: F16H 2306/44 Removing torque from current gears
• CPC Class Codes: F16H 2306/52 Applying torque to new gears
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 61/08 Timing control
• CPC Class Codes: F16H 61/664 Friction gearings

Abstract

A continuously variable transmission apparatus has clutch device having a low speed clutch; a high speed clutch; and, a controller switching the transmission state into any one of a low speed mode and a high speed mode by connecting any one of the clutches, wherein timings for signaling by the controller for switching the connected and disconnected states of the clutches vary according to the switching directions of the low speed and high speed modes; and, a timing for signaling for connecting the low speed clutch with respect to the moment for signaling for cutting off the connection of the high speed clutch in order to switch the high speed mode over to the low speed mode is set earlier than a timing for signaling for connecting the high speed clutch with respect to the moment for signaling for cutting off the connection of the low speed clutch.

Claims

1. A continuosly variable transmission apparatus comprising a toroidal-type continuously variable transmission, a planetary gear mechanism and a clutch device, the clutch device comprising:

a low speed clutch connected in order to increase a speed reducing ratio and disconnected in order to decrease the speed reducing ratio;

a high speed clutch connected in order to decrease a speed reducing ratio and disconnected in order to increase the speed reducing ratio; and

,

a controller for switching over the connected and disconnected states of the respective clutches to each other, the controller switching the transmission state of the continuously variable transmission apparatus into any one of a low speed mode and a high speed mode by connecting any one of the clutches,

wherein timings for signaling by the controller for switching the connected and disconnected states of the clutches vary according to the switching directions of the low speed and high speed modes; and

, a timing for signaling for connecting the low speed clutch with respect to the moment for signaling for cutting off the connection of the high speed clutch in order to switch the high speed mode over to the low speed mode is set earlier than a timing for signaling for connecting the high speed clutch with respect to the moment for signaling for cutting off the connection of the low speed clutch in order to switch the low speed mode over to the high speed mode.

2. A continuously variable transmission apparatus, comprising:

an input shaft connected to a drive source and rotationally driven by the drive source;

an output shaft for taking out power obtained based on the rotational movement of the input shaft;

a toroidal-type continuously variable transmission;

a planetary gear mechanism;

a first power transmission mechanism for transmitting power input to the input shaft through the toroidal-type continuously variable transmission;

a second power transmission mechanism for transmitting power input to the input shaft without passing through the toroidal-type continuously variable transmission;

a controller;

the planetary gear mechanism, comprising;

a sun gear;

a ring gear disposed on the periphery of the sun gear;

a planetary gear interposed between the sun gear and the ring gear so as to be meshingly engaged with the sun gear and the ring gear; and

,

a carrier for supporting the planetary gear so as to be rotated,

wherein the power to be transmitted through the first power transmission mechanism and the power to be transmitted through the second power transmission mechanism are freely transmitted to two of the sun gear, the ring gear and the carrier, and the output shaft is connected to the remaining one of the sun gear, the ring gear and the carrier; and

a mode switching mechanism for switching the state of the power input to the input shaft when the power is transmitted through the first and second power transmission mechanisms to the planetary gear mechanism,

wherein the mode switching mechanism switches over first and second modes to each other, the first mode for transmitting the power by at least only the first power transmission mechanism, the second mode for transmitting the power by both of the first and second power transmission mechanisms,

the controller connects only one of clutches constituting the mode switching mechanism to thereby set the transmission state of the continuously variable transmission apparatus into one of a low speed mode and a high speed mode, the low speed mode being one of the first and second modes, the high speed mode being the other of the first and second modes, and

timings for signaling by the controller for switching the connection and disconnection of the clutches vary according to the switching directions of the low speed and high speed modes, a timing for signaling for connecting a low speed clutch to be connected when realizing the low speed mode with respect to the moment for signaling for cutting off the connection of a high speed clutch to be connected when realizing the high speed mode in order to switch over the high speed mode to the low speed mode is set earlier than a timing for signaling for connecting the high speed clutch with respect to the moment for signaling for cutting off the connection of the low speed clutch in order to switch over the low speed mode to the high speed mode.

3. A continuously variable transmission apparatus, comprising:

an input shaft connected to a drive source and rotationally driven by the drive source;

an output shaft for taking out power obtained based on the rotational movement of the input shaft;

a toroidal-type continuously variable transmission including an input side disk, an output side disk, power rollers interposed between the input side and output side disks so as to be swingly rotatable, and trunnions for supporting the power rollers;

a transmission control valve for shifting the trunnions;

a feedback mechanism for transmitting the shift amounts of the trunnions to the transmission control valve for feedback so that a transmission ratio between the input and output disks provide a target value;

a planetary gear mechanism including three elements, that is, a sun gear, a carrier and a ring gear;

a first power transmission system for transmitting the power input to the input shaft to the output shaft through the toroidal-type continuously variable transmission;

a second power transmission system for transmitting the power input to the input shaft to the output shaft without passing through the toroidal-type continuously variable transmission, the power to be transmitted through the first power transmission system and the power to be transmitted through the second power transmission system being joined to two of the three elements of the planetary gear mechanism, the remaining one of the three elements being connected to the output shaft;

a clutch mechanism, when advancing a vehicle, for switching over a first mode on the low speed side and a second mode on the high speed side to each other; and

,

a control device, when switching over the first and second modes to each other, for controlling the transmission control valve simultaneously with the switching operation of the clutch mechanism within the time during which the clutch mechanism is switched, thereby restricting variations in the transmission ratio of the toroidal-type continuously variable transmission,

wherein the control device, when the clutch mechanism is switched from the first mode on the low speed side to the second mode on the high speed side, starts the control of the transmission control valve later than the time when the switching operation of the clutch mechanism is started and completes the control of the transmission control valve at the time when the switching operation of the clutch mechanism is completed; and

,

when the second mode is switched over to the first mode, the control device starts the control of the transmission control valve at the time when the switching operation of the clutch mechanism is started and completes the control of the transmission control valve earlier than the time when the switching operation of the clutch mechanism is completed.