Hybrid powertrain unit for motor vehicles with a variable transmission device between the electric machine and the differential

Patent metadata

Field	Value
Publication number	US-9649927-B2
Application number	US-201514800137-A
Country	US
Kind code	B2
Filing date	Jul 15, 2015
Priority date	Jul 29, 2014
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

A hybrid powertrain unit comprises an engine and a gearbox device with a primary shaft connectable to a shaft of the engine via a clutch device. The gearbox device comprises a secondary shaft with an output pinion meshing with a first crown wheel of a differential, the casing of which is rigidly connected to a casing of the gearbox device. The unit comprises an electric machine configured to operate as an electric motor and as an electric generator, and having a shaft connected by a transmission to a second crown wheel of the differential. In the transmission, arranged between the electric machine shaft and the second crown wheel is an engagement device that can be operated via an electronically controlled actuator. The transmission that connects the electric machine shaft to said second crown wheel includes an auxiliary shift device configured for providing at least two different selectable transmission ratios.

First claim

What is claimed is:

1. A hybrid powertrain unit for a motor vehicle, comprising:
an internal-combustion engine; and
a gearbox device including:
at least one primary shaft, that can be connected to crankshaft of the internal-combustion engine by a clutch device,
at least one secondary shaft, an axis of which is parallel to, and spaced apart from, an axis of said at least one primary shaft and which carries an output pinion;
a plurality of pairs of gears corresponding to a plurality of forward gear ratios, in which one of the gears of each pair of the plurality of pairs of gears is rigidly connected in rotation with respect to one of said at least one primary and secondary shafts and the other is freely rotatable with respect to the other of said at least one primary and secondary shafts; and
a plurality of gear-selection devices for coupling in rotation each of said freely rotatable gears with the shaft on which it is mounted;
a differential, having a first crown wheel meshing with said output pinion of said at least one secondary shaft of the gearbox device;
an electric machine adapted to operate both as an electric motor and as an electric generator and having a casing rigidly connected to a supporting structure of said powertrain unit, and a shaft connected by a connecting transmission to a second crown wheel of said differential;
an engagement device arranged, in said connecting transmission, between the shaft of the electric machine and the second crown wheel of the differential; and
an actuator arrangement for actuating said engagement device,
wherein said connecting transmission includes an auxiliary shift device configured for providing at least two different selectable transmission ratios, and said auxiliary shift device comprises an epicyclic gear train, including:
a sun gear, an outer ring gear, a plurality of planet gears meshing around the sun gear and within the outer ring gear, and a planet carrier carrying the plurality of planet gears,
said sun gear being connectable in rotation with said second crown wheel of the differential,
said planet carrier being connected to the shaft of said electric machine, and
said outer ring gear being axially movable between a first operating position in which it is connected in rotation with the planet carrier and a second operating position in which it is blocked on supporting structure of the powertrain unit; and
a device for selection of a transmission ratio for displacing selectively the outer ring gear between its two operating positions.

2. The unit according to claim 1 , wherein said auxiliary shift device is set between said engagement device and the shaft of the electric machine.

3. The unit according to claim 1 , wherein said auxiliary shift device is provided with an electronically controlled actuator for selection of the transmission ratio.

4. The unit according to claim 1 , wherein said planet carrier is connected to the shaft of the electric machine via a pair of gears.

5. The unit according to claim 1 , wherein the shaft of the electric machine is connected to the crankshaft of the internal-combustion engine at an end thereof opposite to an end connected to the gearbox device.

6. The unit according to claim 5 , wherein the shaft of the electric machine is connected to the crankshaft by a belt transmission including an endless belt engaged on a first pulley connected to the shaft of the electric machine and on a second pulley connected to the crankshaft of the internal-combustion engine.

7. The unit according to claim 6 , wherein set between one of said first and second pulleys of said belt transmission is a further engagement device.

8. The unit according to claim 6 , wherein said belt transmission that connects the shaft of the electric machine to the crankshaft of the internal-combustion engine also controls one or more auxiliary devices of the motor vehicle, the one or more auxiliary devices including one or more of a compressor of an air-conditioning system and a source of negative pressure for a braking system.

9. The unit according to claim 1 , wherein the shaft of the electric machine has an axis parallel to, and spaced apart from, axes of two output shafts of the differential.

10. The unit according to claim 1 , wherein said engagement device is a clutch engagement device and the actuator arrangement comprises an electromagnetic or electrohydraulic actuator and an electronic unit for controlling said actuator.

Assignees

• Fiat Ricerche

Inventors

• Piazza Andrea
• Garabello Marco
• Pregnolato Gianluigi
• Pesola Fabio

Classifications

• B60K6/48

  Parallel type · CPC title

• Y10S903/951

  Assembly or relative location of components · CPC title

• B60K2006/4841

  the gear provides shifting between multiple ratios · CPC title

• B60K2006/4808

  Electric machine connected or connectable to gearbox output shaft · CPC title

• B60K6/547

  the transmission being a stepped gearing · CPC title