Tandem axle disconnect with synchronized overdrive

Patent metadata

Field	Value
Publication number	US-9656545-B2
Application number	US-201414478694-A
Country	US
Kind code	B2
Filing date	Sep 5, 2014
Priority date	Sep 10, 2013
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

A torque transfer assembly for a tandem axle drive train, having a first synchronizer assembly including a first portion arranged to non-rotatably connect to a power input shaft arranged to receive torque from an engine, a second synchronizer assembly, an overdrive gear assembly engageable with the first synchronizer assembly, and an inter-axle differential gear (IAD) arranged to engage first and second power shafts, and engaged with the second synchronizer assembly. In a differential mode, a first torque path is formed from the power input shaft to a first axle through the first synchronizer, the power shafts, the IAD and second synchronizer, and a second torque path is formed from the power input shaft to a second axle through the first synchronizer, the power shafts, and the IAD, and, in overdrive mode, a third torque path is formed from the power input shaft to the first axle through the first synchronizer.

First claim

What is claimed is:

1. A torque transfer assembly for a tandem axle drive train having a first axle, a second axle, and a power input shaft arranged to receive torque from an engine, comprising:
a first synchronizer assembly including a first portion arranged to non-rotatably connect to the power input shaft;
a second synchronizer assembly having a second portion and a third portion;
an overdrive gear assembly; and,
an inter-axle differential gear:
connected with first and second power shafts; and,
connected with said second portion of said second synchronizer assembly;

wherein:
in a differential mode for said torque transfer assembly:
a first torque path is formed from said power input shaft to the first axle through said first synchronizer assembly, said first power shaft, said inter-axle differential gear, and said second power shaft; and,
a second torque path is formed from said power input shaft to the second axle through said first synchronizer assembly, said first power shaft, said inter-axle differential gear, and said second synchronizer assembly; and,

in an overdrive mode for said torque transfer assembly, a third torque path is formed from said power input shaft to said first axle through said first synchronizer assembly and said overdrive gear assembly and said third portion of said second synchronizer assembly is rotatable relative to said first and second power shafts.

2. The torque transfer assembly of claim 1 , wherein said first portion is axially displaceable between first and second positions in said differential and overdrive modes, respectively.

3. The torque transfer assembly of claim 1 , wherein in said overdrive mode, said input power shaft is rotatable with respect to said first power shaft.

4. The torque transfer assembly of claim 3 , wherein in said overdrive mode, an entirety of the torque received from the engine is transmitted through said third torque path.

5. The torque transfer assembly of claim 1 , wherein:
said first synchronizer assembly includes a second portion non-rotatably connected to said first power shaft; and,
in said differential mode, said first portion is axially displaceable to non-rotatably connect to said second portion.

6. The torque transfer assembly of claim 1 , wherein:
said first synchronizer assembly includes a second portion;
said overdrive gear assembly includes a first gear non-rotatably connected to said second portion; and,
in said overdrive mode, said first portion is axially displaceable to non-rotatably connect to said second portion.

7. The torque transfer assembly of claim 6 , further comprising:
a pinion shaft including:
a second gear engaged with the first gear; and,
a third gear arranged to engage a differential gear for said second axle, wherein:

the pinion shaft and the first, second, and third gears are included in the third torque path.

8. The torque transfer assembly of claim 1 , wherein:
said second synchronizer assembly includes:
a second portion non-rotatably connected to a third portion; and,
a fourth portion connected with said inter-axle differential gear; and,
said third portion is included in said second torque path.

9. The torque transfer assembly of claim 8 , further comprising:
a pinion shaft engaged with the third portion and including a gear arranged to engage a differential gear for said second axle, wherein:
the third portion and the pinion shaft are included in the second torque path.

10. The torque transfer assembly of claim 8 , wherein
for said differential mode, said second portion of said second synchronizer assembly is axially displaceable to non-rotatably connect to said fourth portion; or,
in said overdrive mode, said second portion is axially displaceable such that said second portion is rotatable with respect to said fourth portion.

11. The torque transfer assembly of claim 8 , wherein:
said inter-axle differential gear includes:
a first gear non-rotatably connected to said first power shaft;
a second gear connected with said first gear and said fourth portion; and,
a third gear connected with said first gear and said second power shaft;

said first torque path includes said third gear; and,
said second torque path includes said second gear.

12. The torque transfer assembly of claim 1 , further comprising:
a third synchronizer assembly axially displaceable to initiate a differential lock mode for said torque transfer assembly, wherein,
in said differential lock mode, rotation of said first axle is locked to rotation of said second axle.

13. The torque transfer assembly of claim 12 , wherein:
said second synchronizer assembly includes a second portion included in said second torque path;
said inter-axle differential gear includes a first gear non-rotatably connected to said first power shaft; and,
in said differential lock mode, said second portion, said first gear, and said second power shaft are non-rotatably connected.

14. The torque transfer assembly of claim 13 , wherein:
said first synchronizer assembly includes a third portion non-rotatably connected to said first power shaft;
said second synchronizer assembly includes:
a fourth portion non-rotatably connected to said second portion; and,
a fifth portion engaged with said inter-axle differential gear;

said third synchronizer assembly is non-rotatably connected to said first power shaft; and, for said differential lock mode:
said first portion is axially displaceable to non-rotatably connect to said third portion;
said fourth portion is axially displaceable to non-rotatably connect to said fifth portion; and,
said third synchronizer assembly is axially displaceable to non-rotatably connect to said second portion.

15. A torque transfer assembly for a tandem axle drive train having a power input shaft arranged to receive torque from an engine, a first axle, and a second axle, comprising:
a first synchronizer assembly including:
a first portion arranged to non-rotatably connect to the power input shaft and arranged to receive torque from the engine;
a second portion non-rotatably connected to a first power shaft; and,
a third portion;

a second synchronizer assembly including:
a fourth portion arranged to transmit torque to the first axle;
a fifth portion non-rotatably connected to the fourth portion; and,
a sixth portion;

an overdrive gear assembly engagable with said third portion; and,
an inter-axle differential gear:
including a first gear non-rotatably connected to said first power shaft;
connected with said sixth portion; and,
connected with a second power shaft, said second power shaft arranged to transmit torque to a second axle for said tandem axle drive train, wherein:
for a differential mode for said torque transfer assembly:
torque from said power input shaft is transmittable to said first and second axles;
said first portion is displaceable to non-rotatably connect to said second portion;
said fifth portion is displaceable to non-rotatably connect to said sixth portion; and,
said third portion is rotatable with respect to said first portion; and, for an overdrive mode for said torque transfer assembly:
said first portion is displaceable to non-rotatably connect to said third portion;
said fourth portion is axially displaceable such that said fourth portion is rotatable with respect to said sixth portion; and,
said input power shaft is rotatable with respect to said first power shaft.

16. The torque transfer assembly of claim 15 , wherein:
in said differential mode for said torque transfer assembly:
a first

Assignees

• Schaeffler Technologies Gmbh & Co Kg
• Schaeffler Technologies Ag

Inventors

• Dubey Rohan
• Claassen Michael

Classifications

• B60K17/36 Primary

  for driving tandem wheels · CPC title

• B60K23/08

  for changing number of driven wheels {, for switching from driving one axle to driving two or more axles (B60K17/3515 takes precedence)} · CPC title

• F16H2048/02

  Transfer gears for influencing drive between outputs · CPC title

• F16H48/05

  Multiple interconnected differential sets · CPC title