Torque split infinitely variable transmission

• US 6,723,016 B2
• Filed: 09/26/2002
• Issued: 04/20/2004
• Est. Priority Date: 09/27/2001
• Status: Expired due to Fees

• Current Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Original Assignee: Jatco Limited (Nissan Motor Co., Ltd.)
• Inventors: Sumi, Yasuo
• Primary Examiner(s): PANG, ROGER L
• Application Number:
  US10/254,870
• Publication Number:
  US 20030060318A1
• Time in Patent Office: 572 Days
• Field of Search: 475/211, 475/215, 475/216, 475/217, 475/218
• 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

Abstract

In an infinitely variable transmission with a continuously variable transmission (CVT), a planetary gearset, a power recirculation mode clutch, and a direct mode clutch, a torque split mode reduction gear and clutch device is connected to a unit input shaft and located parallel to a power recirculation mode reduction gear and clutch device. The power recirculation mode clutch is provided for inputting a torque greater than a torque through the unit input shaft into the CVT with the power recirculation mode clutch engaged. The torque split mode clutch is provided for inputting a torque smaller than the torque through the unit input shaft into the CVT with the torque split mode clutch engaged. The power recirculation mode clutch, the direct mode clutch, and the torque split mode clutch are selectively engaged and disengaged for establishing either of a power recirculation mode, a direct mode, and a torque split mode.

Claims

1. A torque split infinitely variable transmission comprising:

a continuously variable transmission connected to a unit input shaft of the infinitely variable transmission;

a power recirculation mode reduction gear unit connected to the unit input shaft;

a torque split mode reduction gear unit connected to the unit input shaft;

a planetary gearset comprising;

a first member coupled to an output shaft of the continuously variable transmission;

a second member coupled to a common output shaft common to the power recirculation mode reduction gear unit and the torque split mode reduction gear unit; and

a third member coupled to a unit output shaft of the infinitely variable transmission;

a power recirculation mode clutch interleaved between an output member of the power recirculation mode reduction gear unit and the common output shaft, for inputting a torque greater than a torque through the unit input shaft into the continuously variable transmission when the power recirculation mode clutch is engaged;

a torque split mode clutch interleaved between an output member of the torque split mode reduction gear unit and the common output shaft, for inputting a torque smaller than the torque through the unit input shaft into the continuously variable transmission when the torque split mode clutch is engaged;

a direct mode clutch interleaved between the output shaft of the continuously variable transmission and the unit output shaft of the infinitely variable transmission, for inputting the torque through the unit input shaft into the continuously variable transmission when the direct mode clutch is engaged; and

the power recirculation mode clutch, the direct mode clutch, and the torque split mode clutch being selectively engaged and disengaged for establishing either of a power recirculation mode, a direct mode, and a torque split mode.

2. The torque split infinitely variable transmission as claimed in claim 1, wherein:

the power recirculation mode is established by engaging the power recirculation mode clutch and disengaging both the torque split mode clutch and the direct mode clutch;

the direct mode is established by disengaging both the power recirculation mode clutch and the torque split mode clutch and engaging the direct mode clutch; and

the torque split mode is established by engaging the torque split mode clutch and disengaging both the power recirculation mode clutch and the direct mode clutch.

3. The torque split infinitely variable transmission as claimed in claim 1, wherein:

the output shaft of the continuously variable transmission and the power recirculation mode reduction gear unit are connected in parallel with each other;

a torque split mode reduction gear and clutch device, including the torque split mode reduction gear unit and the torque split mode clutch, is arranged parallel to a power recirculation mode reduction gear and clutch device, including the power recirculation mode reduction gear unit and the power recirculation mode clutch.

4. The torque split infinitely variable transmission as claimed in claim 1, wherein:

a ratio R3/R13 of a reduction ratio R3 of the power recirculation mode reduction gear unit to a reduction ratio R13 of the torque split mode reduction gear unit is set to be equal to a ratio VLow/VHigh of a maximum transmission ratio VLow of the continuously variable transmission to a minimum transmission ratio VHigh of the continuously variable transmission.

5. The torque split infinitely variable transmission as claimed in claim 1, wherein:

the continuously variable transmission comprises a toroidal continuously variable transmission, which has input and output disks coaxially arranged and opposing each other and a direction of rotation of the output disk is reversed relative to a direction of rotation of the input disk.

6. A torque split infinitely variable transmission comprising:

a continuously variable transmission connected to a unit input shaft of the infinitely variable transmission;

a power recirculation mode reduction gear unit connected to the unit input shaft;

a torque split mode reduction gear unit connected to the unit input shaft;

a planetary gearset comprising;

a sun gear coupled to an output shaft of the continuously variable transmission;

a single-planet-pinion carrier coupled to a common output shaft common to the power recirculation mode reduction gear unit and the torque split mode reduction gear unit; and

a ring gear coupled to a unit output shaft of the infinitely variable transmission;

a power recirculation mode clutch provided in a power transmission line extending from the unit input shaft to the single-planet-pinion carrier of the planetary gearset, for inputting a torque greater than a torque through the unit input shaft into the continuously variable transmission when the power recirculation mode clutch is engaged;

a torque split mode clutch provided in the power transmission line extending from the unit input shaft to the single-planet-pinion carrier, for inputting a torque smaller than the torque through the unit input shaft into the continuously variable transmission when the torque split mode clutch is engaged;

a direct mode clutch provided in a power transmission line extending from the output shaft of the continuously variable transmission to the unit output shaft of the infinitely variable transmission, for inputting the torque through the unit input shaft into the continuously variable transmission when the direct mode clutch is engaged; and

the power recirculation mode clutch, the direct mode clutch, and the torque split mode clutch being selectively engaged and disengaged for establishing either of a power recirculation mode, a direct mode, and a torque split mode.

7. A torque split infinitely variable transmission comprising:

a continuously variable transmission connected to a unit input shaft of the infinitely variable transmission;

a power recirculation mode reduction gear unit connected to the unit input shaft;

a torque split mode reduction gear unit connected to the unit input shaft;

a planetary gearset comprising;

a sun gear coupled to an output shaft of the continuously variable transmission;

a single-planet-pinion carrier coupled to a common output shaft common to the power recirculation mode reduction gear unit and the torque split mode reduction gear unit; and

a ring gear coupled to a unit output shaft of the infinitely variable transmission;

a power recirculation mode clutch provided in a power transmission line extending from the unit input shaft to the single-planet-pinion carrier of the planetary gearset, for inputting a torque greater than a torque through the unit input shaft into the continuously variable transmission when the power recirculation mode clutch is engaged;

a torque split mode clutch provided in the power transmission line extending from the unit input shaft to the single-planet-pinion carrier, for inputting a torque smaller than the torque through the unit input shaft into the continuously variable transmission when the torque split mode clutch is engaged;

a direct mode clutch provided in a power transmission line extending from the output shaft of the continuously variable transmission to the unit output shaft of the infinitely variable transmission, for inputting the torque through the unit input shaft into the continuously variable transmission when the direct mode clutch is engaged;

the power recirculation mode clutch, the direct mode clutch, and the torque split mode clutch being selectively engaged and disengaged for establishing either of a power recirculation mode, a direct mode, and a torque split mode;

a reduction gearset comprising;

an output gear of the continuously variable transmission, coaxially arranged with and rotatably supported on the unit input shaft;

a counter gear whose rotation axis is parallel to the unit input shaft; and

a gear fixed onto the output shaft of the continuously variable transmission, and meshingly engages via the counter gear with the output gear of the continuously variable transmission, and coaxially arranged with the sun gear of the planetary gearset;

the power recirculation mode reduction gear unit comprising;

a first input gear coaxially arranged with the unit input shaft; and

a first output gear in meshed-engagement with the first input gear and coaxially arranged with the single-planet-pinion carrier, the first input gear and the first output gear being provided in the power transmission line extending from the unit input shaft to the single-planet-pinion carrier; and

the torque split mode reduction gear unit comprising;

a second input gear coaxially arranged with the unit input shaft and parallel to the first input gear; and

a second output gear in meshed-engagement with the second input gear and coaxially arranged with the single-planet-pinion carrier and parallel to the first output gear, the second input gear and the second output gear provided in the power transmission line extending from the unit input shaft to the single-planet-pinion carrier.

8. The torque split infinitely variable transmission as claimed in claim 7, wherein:

a first revolution synchronous point for switching between the power recirculation mode and the direct mode is set as a mode switching point corresponding to a maximum transmission ratio VLow of the continuously variable transmission that satisfies a first expression VLow=R3/R1, where R3 is a reduction ratio of the power recirculation mode reduction gear unit and R1 is a reduction ratio of the reduction gearset; and

a second revolution synchronous point for switching between the direct mode and the torque split mode is set as a mode switching point corresponding to a minimum transmission ratio VHigh of the continuously variable transmission that satisfies a second expression VHigh=R13/R1, where R13 is a reduction ratio of the torque split mode reduction gear unit and R1 is the reduction ratio of the reduction gearset.