Electro-Mechanical One-Way-Clutch and Method of Operation

Patent metadata

Field	Value
Publication number	US-2016356377-A1
Application number	US-201514728181-A
Country	US
Kind code	A1
Filing date	Jun 2, 2015
Priority date	Jun 2, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A transmission utilizes an electro-magnetically actuated selectable one-way-clutch. The one-way-clutch prevents rotation of a transmission member in both directions when a current exceeds a threshold and permits rotation in only one direction otherwise. To prevent un-intended engagement, a switch interrupts the current unless a second current exceeds a threshold. In order to engage the one-way-clutch, both currents are set above their respective thresholds by a controller. In the event of a single fault such as a short circuit, the system continues to function normally. The controller may periodically test for a fault by intentionally setting one current above its threshold and the other below its threshold and determining the state of the one-way-clutch by measuring speeds of transmission elements.

First claim

What is claimed is:

1 . A transmission comprising:
a selectable one-way-clutch configured to prevent relative rotation between two transmission elements in response to a first current exceeding a first threshold; a switch configured to interrupt the first current in response to a second current not exceeding a second threshold; and a controller configured to set a state of the selectable one-way-clutch in response to manipulation of a shift lever by manipulating the first and second currents.

2 . The transmission of claim 1 wherein the selectable one-way-clutch is configured to permit relative rotation in only one direction in response to the first current being less than the first threshold.

3 . The transmission of claim 2 further comprising:
a first wire electrically connecting the controller to the selectable one-way-clutch; and
a second wire electrically connecting the switch to the controller, the first current flowing through the first and second wires.

4 . The transmission of claim 3 further comprising:
a third wire electrically connecting the switch to the controller, the second current flowing through the second and third wires.

5 . The transmission of claim 3 further comprising:
a third wire electrically connecting the switch to the controller; and
a fourth wire electrically connecting the switch to the controller, the second current flowing through the third and fourth wires.

6 . The transmission of claim 3 wherein one of the two transmission elements is a non-rotating transmission case.

7 . The transmission of claim 2 wherein the controller is programmed to:
engage the selectable one-way-clutch in response to selection of a reverse range by setting the first and second currents to levels exceeding the first and second thresholds respectively; and
dis-engage the selectable one-way-clutch in response to selection of a drive range by setting the first and second electrical currents to levels less than the first and second thresholds respectively.

8 . The transmission of claim 7 wherein the controller is further programmed to test for a fault by:
regulating one of the first and second electrical currents to a level exceeding the corresponding threshold;
regulating another of the first and second electrical currents to a level less than the corresponding threshold;
increasing a torque capacity of a friction clutch; and
setting an error code in response to a transmission speed ratio being inconsistent with the selectable one-way-clutch being disengaged.

9 . An electrically actuated clutch comprising:
first, second, third, and fourth terminals; a switch configured to establish a circuit between the first and second terminals in response to a first current between the third and fourth terminals exceeding a first threshold; and a one-way-clutch configured to preclude relative rotation between first and second races in response to a second current between the first and second terminals exceeding a second threshold.

10 . A method of operating a transmission comprising:
in response to selection of a reverse range, engaging a selectable one-way-clutch by regulating a first and a second current to levels exceeding first and second thresholds respectively; and in preparation for an upshift, dis-engaging the selectable one-way-clutch in one direction by regulating the first and second currents to levels less than the first and second thresholds respectively.

11 . The method of claim 10 wherein the upshift is a shift from a launch ratio to a next highest forward speed ratio.

12 . The method of claim 10 further comprising:
while regulating the first current to a first level exceeding the first threshold and regulating the second current to a second level less than the second threshold, increasing a torque capacity of a friction clutch; and
setting an error code in response to a transmission speed ratio being inconsistent with the selectable one-way-clutch being disengaged.

13 . The method of claim 12 wherein the friction clutch is an on-coming clutch for the upshift and the transmission speed ratio does not change in response to increasing the torque capacity.

14 . The method of claim 12 wherein the torque capacity of the friction clutch is increased while a transmission output shaft is stationary and a transmission turbine shaft slows down in response to increasing the torque capacity.

Assignees

• Ford Global Tech Llc

Inventors

• Bird Norman Jerry
• Riedle Bradley Dean
• Espinosa Ricardo Humberto

Classifications

• F16H3/66

  composed of a number of gear trains without drive passing from one train to another · CPC title

• F16D2500/1087

  Planetary gearing · CPC title

• F16D2500/50287

  Torque control · CPC title

• F16D28/00

  Electrically-actuated clutches (arrangements for synchronisation F16D23/02; clutches actuated directly by means of an electromagnet F16D27/00; automatic clutches F16D43/00 - F16D45/00; external control F16D48/00) · CPC title

• F16H61/12

  Detecting malfunction or potential malfunction, e.g. fail safe (in control of hydrostatic gearing F16H61/4192) {; Circumventing or fixing failures} · CPC title