Electric continuously variable transmission

• US 6,371,878 B1
• Filed: 08/22/2000
• Issued: 04/16/2002
• Est. Priority Date: 08/22/2000
• Status: Expired due to Term

• Current Assignee: New Venture Gear, Incorporated (Magna International Incorporated)
• Original Assignee: New Venture Gear, Incorporated (Magna International Incorporated)
• Inventors: Bowen, Thomas C.
• Primary Examiner(s): ESTREMSKY, SHERRY LYNN
• Application Number:
  US09/643,238
• Time in Patent Office: 602 Days
• Field of Search: 475/5, 180/65.2, 180/65.7
• US Class Current: 475/5
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/383 One-way clutches or freewheel devices
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: F16H 2037/102 the input or output shaft of the transmission is connected or connectable to two or more differentials
• CPC Class Codes: F16H 3/727 with at least two dynamo electric machines for creating an electric power path inside the gearing, e.g. using generator and motor for a variable power torque path special adapted for a hybrid electric vehicle B60K6/20
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/91 Orbital, e.g. planetary gears
• CPC Class Codes: Y10S 903/913 One way
• CPC Class Codes: Y10S 903/916 with plurality of drive axles
• CPC Class Codes: Y10S 903/918 Continuously variable

Abstract

An electric continuously variable transmission includes first and second planetary splitters each having a corresponding electric motor/generator. Both planetary splitters are integrally linked to an input shaft which transfers torque and rotational motion from a combustion engine. The electric motor/generators switch between driving its corresponding planetary splitter and being driven by its corresponding planetary splitter to generate various ranges, providing variable transmission speed ratios. A lock-up clutch may be selectively engaged producing an overdrive range for cruising speeds. The electric continuously variable transmission drives a first differential which further drives a pair of wheels. A controller and battery are also provided for respectively managing the various electric motor/generators and either storing or providing energy for the system. Implementation of the electric continuously variable transmission in a hybrid vehicle is also possible with the addition of a second differential and a third electric motor/generator for driving the second differential.

Claims

1. A continuously variable transmission comprising:

first and second planetary splitters;

an input shaft in mechanical communication with each of said first and second planetary splitters;

an output shaft in mechanical communication with each of said first and second planetary splitters;

a first electric motor/generator for selectively driving or generating electrical energy from said first planetary splitters; and

a second electric motor/generator for selectively driving or generating electrical energy from said second planetary splitter;

wherein a low speed range operating mode is achieved through said second electric motor/generator generating electrical energy and feeding said electrical energy to said first electric motor/generator, a mid speed range operating mode is achieved through said first electric motor/generator generating electrical energy and feeding said electrical energy to said second electric motor/generator, and a high speed range is achieved through a lock-up clutch locking a component of said first planetary splitter and said second electric motor/generator generating electrical energy and feeding said electrical energy to said first electric motor/generator.

2. The continuously variable transmission of claim 1 wherein said output shaft is driven by a ring gear of said first planetary splitter and a carrier of said second planetary splitter.

3. The continuously variable transmission of claim 1 further comprising a controller for managing driving and generating modes of each of said first and second electric motor/generators.

4. The continuously variable transmission of claim 1 further comprising a battery for powering either of said first and second electric motor/generators.

5. A continuously variable transmission comprising:

a first and second planetary splitters;

a lock-up clutch in mechanical communication with said first planetary splitter;

an input shaft in mechanical communication with each of said first and second planetary splitters;

an output shaft in mechanical communication with each of said first and second planetary splitters;

a first electric motor/generator for selectively driving or generating electrical energy from said first planetary splitter; and

a second electric motor/generator for selectively driving or generating electrical energy from said second planetary splitter.

6. A continuously variable transmission comprising:

first and second planetary splitters;

an input shaft in mechanical communication with each of said first and second planetary splitters, wherein said input shaft drives a carrier of said first planetary splitter and a sun gear of said second planetary splitter;

an output shaft in mechanical communication with each of said first and second planetary splitters;

a first electric motor/generator for selectively driving or generating electrical energy from said first planetary splitter; and

a second electric motor/generator for selectively driving or generating electrical energy from said second planetary splitter.

7. A hybrid vehicle comprising:

a combustion engine;

a continuously variable transmission operably attached to said combustion engine, and continuously variable transmission including;

first and second planetary splitters;

an input shaft in mechanical communication with each of said first and second planetary splitters;

an output shaft in mechanical communication with each of said first and second planetary splitters;

a first electric motor/generator for selectively driving or generating electrical energy from said first planetary splitter;

a second electric motor/generator for selectively driving or generating electrical energy from said second planetary splitter;

a first differential driven by said continuously variable transmission wherein said first differential drives a first pair of wheels;

a second differential connected to a second pair of wheels for driving said second pair of wheels;

a third electric motor/generator for driving said second differential; and

a battery for powering said first, second and third electric motor/generators and for storing energy produced by said first, second and third motor/generators when said first, second and third electric motor/generators are selectively operated in a power generation mode.

8. The hybrid vehicle of claim 7, further comprising a controller for managing said first, second and third electric motor/generators.

9. The hybrid vehicle of claim 7 wherein said input shaft drives a carrier of said first planetary splitter and a sun gear of said second planetary splitter.

10. The hybrid vehicle of claim 7 wherein said output shaft is driven by a ring gear of said first planetary splitter and a carrier of said second planetary splitter.

11. The hybrid vehicle of claim 7 further comprising a parking mechanism for engaging said output shaft.

12. A hybrid vehicle comprising:

a combustion engine;

a continuously variable transmission operably attached to said combustion engine, said continuously variable transmission including;

first and second planetary splitters;

an input shaft in mechanical communication with each of said first and second planetary splitters;

an output shaft in mechanical communication with each of said first and second planetary splitters;

a first electric motor/generator for selectively driving or generating electrical energy from said first planetary splitter;

a second electric motor/generator for selectively driving or generating electrical energy from said second planetary splitter; and

a first differential driven by said continuously variable transmission wherein said first differential drives a first pair of wheels;

wherein a low speed range operating mode is achieved through said second electric motor/generator generating electrical energy and feeding said electrical energy to said first electric motor/generator, a mid speed range operating mode is achieved through said first electric motor/generator generating electrical energy and feeding said electrical energy to said second electric motor/generator, and a high speed range operating mode is achieved through a lock-up clutch locking a component of said first planetary splitter and said second electric motor/generator generating electrical energy and feeding said electrical energy to said first electric motor/generator.

13. A transmission for a hybrid vehicle having an internal combustion engine and a driveline, comprising:

an input shaft adapted to be selectively driven by the engine;

an output shaft adapted to drive the driveline;

a first planetary gearset having a first sun gear, a first ring gear, and a set of first planet gears meshed with said first sun gear and said first ring gear, said planet gears rotatably supported on a first carrier that is fixed to said input shaft;

a second planetary gearset having a second sun gear fixed to said input shaft, a second ring gear, and a set of second planet gears meshed with said second sun gear and second ring gear, said second planet gears rotatably supported from a second carrier fixed to said first ring gear and said output shaft;

a first motor/generator for selectively driving or generating electrical energy from said first sun gear;

a second motor/generator for selectively driving or generating electrical energy from said second ring gear;

an input clutch for selectively coupling the engine to said input shaft;

a brake for selectively braking rotation of said first sun gear; and

a control system for controlling actuation of said first and second motor/generators, said input clutch and said brake.