Integrated torque limiter/no-back device

Patent metadata

Field	Value
Publication number	US-9255632-B2
Application number	US-201213478172-A
Country	US
Kind code	B2
Filing date	May 23, 2012
Priority date	May 23, 2012
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

An integrated torque limiter/no-back device for use in an actuator with an input shaft, an output and gear reduction. The device includes an input ramp to receive torque from the input shaft; a combined ramp to transfer torque; an output ramp to transfer torque to the gear reduction; one or more balls between the input ramp and the combined ramp and between the combined ramp and the output ramp to transfer torque; and a brake for causing torque to be grounded and for preventing backdriving of the input shaft by preventing movement of one or more of the input ramp, the combined ramp and the output ramp when a torque threshold has been met. The input ramp and the output ramp are a no-back ramp and a torque limiter ramp, respectively, and the device also includes a pin between the combined ramp and one or more of the no-back ramp and the gear reduction for transferring torque.

First claim

The invention claimed is:

1. An integrated torque limiter/no-back device for use in an actuator with an input shaft driven by a power drive unit, an output and gear reduction for transmitting rotary motion from the input shaft to the output, the device comprising:
an input ramp, wherein the input shaft transfers torque to the input ramp, and wherein the input ramp is one of a no-back ramp and a torque limiter ball ramp;
a combined ramp to transfer torque, wherein the combined ramp comprises:
a unitary body having a first face and a second face opposite the first face;

an output ramp to transfer torque to the gear reduction, wherein the output ramp is the other of the no-back ramp and the torque limiter ball ramp;
one or more balls between the input ramp and the first face of the unitary body to transfer torque from the input ramp to the combined ramp;
one or more balls between the output ramp and the second face of the unitary body to transfer torque from the combined ramp to the output ramp;
a pin extending from the combined ramp to the output ramp for transferring torque;
a brake for causing torque to be grounded by preventing movement of one or more of the input ramp, the combined ramp and the output ramp when a torque threshold has been met; and
a second brake for preventing backdriving of the input shaft by preventing movement of one or more of the torque limiter ball ramp, the combined ball ramp and the no-back ball ramp when the torque threshold has been met.

2. The integrated torque limiter/no-back device of claim 1 , wherein the pin connects the combined ramp and one or more of the no-back ramp and the gear reduction to transfer torque between the no-back ramp and/or the gear reduction and the combined ramp when the torque threshold has not yet been met.

3. The integrated torque limiter/no-back device of claim 1 , wherein the first brake engages one or more of the torque limiter ball ramp and the combined ball ramp to perform a torque limiting function, and the second brake engages one or more of the no-back ball ramp and the combined ball ramp to perform a no-back function.

4. The integrated torque limiter/no-back device of claim 1 , wherein the first brake and the second brake comprise one of brake plates and a cone brake.

5. The integrated torque limiter/no-back device of claim 1 , wherein the torque limiter ramp is the input ramp.

6. The integrated torque limiter/no-back device of claim 1 , wherein when the torque threshold has been met, the torque limiter ramp engages the brakes, and any additional torque is not transferred to the gear reduction.

7. An actuator comprising:
an input shaft driven by a power drive unit;
an output;
a gear reduction for transmitting rotary motion from the input shaft to the output; and
an integrated torque limiter/no-back device to ground additional torque from the power drive unit when engaged and to prevent backdriving of the input shaft, wherein the integrated torque limiter/no-back device comprises:
an input ramp, wherein the input shaft transfers torque to the input ramp, and wherein the input ramp is one of a no-back ramp and a torque limiter ball ramp;
a combined ball ramp that transmits torque, wherein the combined ball ramp comprises:
a unitary body having a first face and a second face opposite the first face;

one or more balls between the input ramp and the first face to transfer torque from the input ramp to the combined ball ramp;
an output ramp that transfers torque to the gear reduction, wherein the output ramp is the other of the no-back ramp and the torque limiter ball ramp;
one or more balls between the output ramp and the second face to transfer torque from the combined ball ramp to the output ramp; and
a first brake to prevent movement of one or more of the torque limiter ball ramp, the combined ball ramp, and the no-back ball ramp when a torque threshold has been met;
and a second brake to prevent movement of one or more of the torque limiter ball ramp, the combined ball ramp and the no-back ball ramp when the torque threshold has been met.

8. The actuator of claim 7 , wherein the input ramp is the torque limiter ball ramp and the output ramp is the no-back ramp, and wherein the integrated torque limiter/no-back device further comprises:
a pin that connects the combined ball ramp to the no-back ball ramp and the gear reduction, wherein the no-back ball ramp connects to the gear reduction.

9. The actuator of claim 7 , wherein the first brake engages one or more of the torque limiter ball ramp and the combined ball ramp to perform a torque limiting function, and the second brake engages one or more of the no-back ball ramp and the combined ball ramp to perform a no-back function.

10. The actuator of claim 7 , wherein the first brake and the second brake comprise one of brake plates and a cone brake.

11. A method of limiting torque and backdriving through an actuator, the method comprising:
receiving input torque at an input shaft;
transmitting the input torque through an integrated torque limiter/no-back device, wherein the integrated torque limiter/no-back device comprises:
an input ramp, wherein the input shaft transfers torque to the input ramp, and wherein the input ramp is one of a no-back ramp and a torque limiter ball ramp;
a combined ramp to transfer torque, wherein the combined ramp comprises:
a unitary body having a first face and a second face opposite the first face;

an output ramp to transfer torque to the gear reduction, wherein the output ramp is the other of the no-back ramp and the torque limiter ball ramp;
one or more balls between the input and the first face of the unitary body to transfer torque from the input ramp to the combined ramp;
one or more balls between the output ramp and the second face of the unitary body to transfer torque from the combined ramp to the output ramp;
a pin extending from the combined ramp to the output ramp for transferring torque;
a first brake for causing torque to be grounded by preventing movement of one or more of the input ramp, the combined ramp and the output ramp when a torque threshold has been met; and
a second brake for preventing backdriving of the input shaft by preventing movement of one or more of the torque limiter ball ramp, the combined ball ramp and the no-back ramp when the torque threshold has been met;

sensing torque transferred through the one or more balls between the torque limiter ramp and the combined ramp;
engaging the torque limiter when the torque transferred between the torque limiter ramp and the combined ramp reaches the torque threshold, causing the torque limiter ramp and the combined ramp to separate and engage the first brake;
sensing torque transferred between the no-back ramp and the combined ramp; and
engaging the no-back device when the torque transferred between the no-back ramp and the combined ramp reaches the torque threshold, causing the pin to disengage one of the no-back ramp and combined ramp, causing the torque to be transferred through the one or more balls and force the no-back ramp and the combined ramp to separate and engage the second brake.

Assignees

• Finney Adam M
• Hamilton Sundstrand Corp

Inventors

• Finney Adam M

Classifications

• F16D43/218

  with conical friction surfaces · CPC title

• F16H35/10 Primary

  Arrangements or devices for absorbing overload or preventing damage by overload · CPC title

• F16D2125/38

  with plural cam or ball-ramp mechanisms arranged concentrically with the brake rotor axis · CPC title

• B64D2045/001

  for indicating symmetry of flaps deflection · CPC title

• F16D43/215

  with flat friction surfaces, e.g. discs · CPC title