Wrap spring park brake system, apparatus and method

Patent metadata

Field	Value
Publication number	US-9995351-B2
Application number	US-201615012412-A
Country	US
Kind code	B2
Filing date	Feb 1, 2016
Priority date	Jul 2, 2013
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

A park brake system for an electric motor actuator is provided. The system may comprise a wrap spring that may rotatably engage the shaft. In this regard, the system may be configured to exert a radial force on a shaft of the electric motor actuator to lock the actuator. Moreover, in various embodiments, the system may be bi-stable.

First claim

What is claimed is:

1. An electric motor actuator, comprising:
a shaft;
a housing;
a rotor cup rotatably installed about at least a portion of the shat;
a spring installable on the shaft, the spring comprising a first spring tang fixed to an integral portion of the housing and a movable second spring tang coupled to the rotor cup;
a magnet coupled to the rotor cup; and
a stator comprising a coil, wherein the rotor cup rotates in a first direction in response to the coil being energized and biasing the magnet, wherein the spring tightens on the shaft in response to the rotor cup rotating the second spring tang, and wherein the rotor cup rotates the second spring tang in a second direction in response to the coil being energized, allowing the spring to release tension on the shaft, the first direction being different from the second direction.

2. The electric motor actuator of claim 1 , wherein the rotor cup is installable in the housing and wherein the rotor cup is rotatable with respect to the housing.

3. The electric motor actuator of claim 1 , wherein the rotor cup is configured to surround at least a portion of the shaft.

4. The electric motor actuator of claim 1 , wherein the stator comprises a plurality of pole teeth, wherein a first portion of the plurality of pole teeth are configured to emit a first flux in response to a first condition and wherein a second portion of the plurality of pole teeth are configured to emit a second flux in response to a second condition.

5. The electric motor actuator of claim 1 , wherein the coil is energized in response to a load on the electric motor actuator being above a predetermined threshold.

6. The electric motor actuator of claim 5 , further comprising a first mechanical stop and
a second mechanical stop, the first mechanical stop and the second mechanical stop installed in the electric motor actuator to prevent the magnet from reaching a magnetically stable condition.

7. A method, comprising:
monitoring an electric motor actuator;
detecting a load on the electric motor actuator;
energizing a coil assembly in response to the load being above a predetermined threshold;
actuating a rotor cup situated in a housing in response to energizing the coil assembly in a first direction, wherein the rotor cup is coupled to a movable second spring tang of a spring and rotates the second spring tang to constrict a shaft to lock the electric motor actuator, a first spring tang being fixed to the housing and
energizing the coil assembly to cause the rotor cup to rotate the second spring tang in a second direction, allowing the spring to release tension on the shaft, the first direction being different from the second direction.

8. The method of claim 7 , wherein the predetermined threshold is time.

9. The method of claim 7 , wherein the spring is a wrap spring installed on the shaft.

10. The method of claim 7 , wherein energizing the coil assembly actuates a magnet that is coupled to the rotor cup causing the rotor cup to rotate.

Assignees

• Goodrich Corp

Inventors

• Drennen David
• Klode Harald
• Rehfus Kevin

Classifications

• F16D49/02 Primary

  shaped as a helical band or coil with more than one turn, with or without intensification of the braking force by the tension of the band or contracting member (similar clutches F16D13/08) · CPC title

• B60T1/062

  acting on transmission parts · CPC title

• F16D2121/20

  using electromagnets · CPC title

• F16D65/14

  Actuating mechanisms for brakes; Means for initiating operation at a predetermined position (brake control systems, parts thereof B60T) · CPC title

• F16D2125/18

  Mechanical mechanisms · CPC title