System and method for multiplexing gear engagement control and providing fault protection in a toroidal traction drive automatic transmission

Patent metadata

Field	Value
Publication number	US-9267582-B2
Application number	US-201314076869-A
Country	US
Kind code	B2
Filing date	Nov 11, 2013
Priority date	Dec 16, 2009
Publication date	Feb 23, 2016
Grant date	Feb 23, 2016

Abstract

An apparatus for multiplexing gear engagement control in an automatic transmission is provided. At least two friction engagement devices are configured to selectively engage and disengage a different gear ratio of the transmission. A trim system is configured to selectively supply engagement and disengagement pressures to at least one fluid passageway. A first control valve is fluidly coupled directly to the at least one fluid passageway and directly to each of the at least two friction engagement devices. The first control valve is configured to selectively route the engagement and disengagement pressures through the first control valve directly to the at least two friction devices.

First claim

What is claimed is:

1. An apparatus for multiplexing gear engagement control in an automatic transmission operable in a plurality of operating modes, the apparatus comprising:
a first and a second friction engagement device, each of the first and second friction engagement devices selectively engageable and disengageable to select a different gear ratio of the transmission,
a trim system configured to selectively supply fluid at one of (i) an engagement pressure and (ii) a disengagement pressure to a first fluid passageway and a second fluid passageway in one of the plurality of operating modes, and
a first control valve fluidly coupled directly to the first fluid passageway and the second fluid passageway and directly to the first friction engagement device and the second friction engagement device,
wherein the first control valve is configured to contemporaneously route fluid at the engagement pressure to the first friction engagement device to engage the first friction engagement device and to the second friction engagement device to engage the second friction engagement device in a fault condition occurring during a transition between the plurality of operating modes of the transmission.

2. The apparatus of claim 1 , wherein the first control valve is configured to (i) selectively route fluid at the engagement pressure to the first friction engagement device to the engage the first friction engagement device in one of the plurality of operating modes, and (ii) contemporaneously route fluid at the disengagement pressure to the second friction engagement device to disengage the second friction engagement device in the one of the plurality of operating modes.

3. The apparatus of claim 2 , further comprising a second control valve fluidly coupled directly to each of the first and second fluid passageways, the second control valve configured to selectively route the engagement pressure in one of the first and second fluid passageways and the disengagement pressure in one of the first and second fluid passageways through the second control valve to the first control valve for further selective routing by the first control valve to each of the first and second friction engagement devices.

4. The apparatus of claim 3 , further comprising a third friction engagement device selectively engageable and disengageable to select another different gear ratio of the transmission,
wherein the second control valve is fluidly coupled directly to the third friction engagement device, and wherein the second control valve is configured to selectively route one of the engagement and disengagement pressures in the second fluid passageway through the second control valve directly to the third friction engagement device.

5. The apparatus of claim 4 , wherein the first control valve comprises a first spool having a stroked position and a de-stroked position and the second control valve comprises a second spool having a stroked position and a de-stroked position, and wherein the first and second control valves are together configured to supply the engagement pressure in at least one of the first and second fluid passageways to at least one of the first, second, and third friction engagement devices to thereby engage the at least one of the first, second, and third friction engagement devices in all possible position combinations of the first and second spools.

6. The apparatus of claim 5 , wherein the first spool of the first control valve has a stroked position in the fault condition, and wherein the second spool of the second control valve has a de-stroked position in the fault condition.

7. The apparatus of claim 5 , wherein the second control valve is fluidly coupled directly to a first main pressure fluid passageway and also directly to a third fluid passageway, the second control valve configured to selectively route pressure in the first main pressure fluid passageway to the third fluid passageway.

8. The apparatus of claim 6 , wherein the second control valve routes fluid at the disengagement pressure to the third friction engagement device to disengage the third friction engagement device in the fault condition.

9. The apparatus of claim 7 , wherein the second control valve is fluidly coupled directly to a second main pressure fluid passageway, the second control valve configured to selectively route pressure in the second main pressure fluid passageway to the third fluid passageway.

10. The apparatus of claim 9 , wherein the automatic transmission is a toroidal traction drive transmission further comprising a variator and a variator control system for controlling operation of the variator, and wherein the second control valve is configured to selectively route pressure in the first and second main pressure fluid passageways to a component of the variator control system via the third fluid passageway.

11. An apparatus for multiplexing gear engagement control in an automatic transmission operable in a plurality of operating modes, the apparatus comprising:
a first control valve fluidly coupled to a first fluid passageway, a second fluid passageway, a first friction engagement device, and a second friction engagement device,
wherein the first control valve is configured to contemporaneously route fluid at (i) an engagement pressure to the first friction engagement device to engage the first friction engagement device and (ii) a disengagement pressure to the second friction engagement device to disengage the second friction engagement device in a fault condition occurring during a transition between the plurality of operating modes of the transmission.

12. The apparatus of claim 11 , further comprising a second control valve fluidly coupled directly to each of the first and second fluid passageways, the second control valve configured to selectively route the engagement pressure in one of the first and second fluid passageways and the disengagement pressure in one of the first and second fluid passageways through the second control valve to the first control valve for further selective routing by the first control valve to each of the first and second friction engagement devices.

13. The apparatus of claim 12 , wherein the second control valve is fluidly coupled directly to a third friction engagement device, and wherein the second control valve is configured to selectively route one of the engagement and disengagement pressures in the second fluid passageway through the second control valve directly to the third friction engagement device.

14. The apparatus of claim 13 , wherein the first control valve comprises a first spool having a stroked position and a de-stroked position and the second control valve comprises a second spool having a stroked position and a de-stroked position, and wherein the first and second valves are together configured to supply the engagement pressure in at least one of the first and second fluid passageways to at least one of the first, second, and third friction engagement devices to thereby engage the at least one of the first, second, and third friction engagement devices in all possible position combinations of the first and second spools.

15. The apparatus of claim 14 , wherein the first spool of the first control valve has a de-stroked position in the fault condition, and wherein the second spool of the second control valve has a de-stroked position in the fault condition.

16. The apparatus of claim 15 , wherein the second control valve is configured to route fluid at the engagement pressure to the third friction engagement device to engage the third friction engagement device in the fault cond

Assignees

• Long Charles F
• Weber Darren J
• Fuller John William Edward
• Allison Transm Inc

Inventors

• Long Charles F
• Weber Darren J
• Fuller John William Edward

Classifications

• F16H61/664

  Friction gearings · CPC title

• F16D2048/0209

  characterised by fluid valves having control pistons, e.g. spools · CPC title

• F16H61/0206 Primary

  Layout of electro-hydraulic control circuits, e.g. arrangement of valves · CPC title

• F16D48/062

  of a clutch system with a plurality of fluid actuated clutches · CPC title

• F16D48/02 Primary

  Control by fluid pressure · CPC title