Bistable Brake

• US 10,612,610 B2
• Filed: 04/12/2018
• Issued: 04/07/2020
• Est. Priority Date: 04/12/2018
• Status: Active Grant

• Current Assignee: Warner Electric Do Brasil LTDA (Regal Rexnord Corp.)
• Original Assignee: Warner Electric Do Brasil LTDA (Regal Rexnord Corp.)
• Inventors: Silvestrini, Richard Larry, Nyquist, Stephen E., Uffelman, Bradley Lyn
• Primary Examiner(s): Rodriguez, Pamela
• Application Number:
  US15/951,712
• Publication Number:
  US 20190316642A1
• Time in Patent Office: 726 Days
• Field of Search: 188171, 188161, 188163, 188164, 188173
• CPC Class Codes: F16D 2121/14 Mechanical
• CPC Class Codes: F16D 2121/20 using electromagnets
• CPC Class Codes: F16D 2121/22 for releasing a normally applied brake
• CPC Class Codes: F16D 2129/08 Electromagnets
• CPC Class Codes: F16D 2200/0021 Steel
• CPC Class Codes: F16D 2200/0052 Carbon
• CPC Class Codes: F16D 55/02 with axially-movable discs or pads pressed against axially-located rotating members
• CPC Class Codes: F16D 55/08 Mechanically-actuated brakes
• CPC Class Codes: F16D 55/22 by clamping an axially-located rotating disc between movable braking members, e.g. movable brake discs or brake pads
• CPC Class Codes: F16D 55/30 mechanically actuated
• CPC Class Codes: F16D 63/002 Brakes with direct electrical or electro-magnetic actuation
• CPC Class Codes: F16D 65/18 adapted for drawing members together , e.g. for disc brakes
• CPC Class Codes: F16D 65/186 with full-face force-applying member, e.g. annular

Abstract

An electromagnetic brake is provided in which short duration current pulses move the brake between engaged and disengaged states. A first current pulse having a first polarity is delivered to a conductor within a field shell when the brake is engaged and establishes an electromagnetic circuit including the field shell and an armature plate that urges the armature plate away from a rotating friction plate and towards the field shell to disengage the brake. A magnetic circuit is maintained after termination of the first current pulse due to a remanence in at least one of the armature plate and the field shell. A second current pulse having a second polarity opposite the first polarity delivered to the conductor when the brake is disengaged weakens the magnetic circuit thereby allowing a spring to move the armature plate away from the field shell and towards the friction plate to engage the brake.

Claims

1. A brake, comprising:

a friction plate configured for coupling to a shaft for rotation with the shaft about an axis of rotation;

a pressure plate disposed about the axis on a first side of the friction plate and fixed against rotation;

an armature plate disposed about the axis on a second side of the friction plate;

a field shell disposed about the axis on an opposite side of the armature plate relative to the friction plate;

a spring biasing the armature plate in a first axial direction towards the friction plate and away from the field shell to engage the brake; and

,

a conductor disposed within the field shell

wherein delivery of a first current pulse having a first polarity to the conductor when the brake is engaged establishes an electromagnetic circuit including the armature plate and the field shell that urges the armature plate in a second axial direction away from the friction plate and towards the field shell to disengage the brake, a magnetic circuit including the armature plate and the field shell is maintained after termination of the first current pulse due to a remanence in at least one of the armature plate and the field shell, the magnetic circuit generating an attractive force greater than a biasing force of the spring, and delivery of a second current pulse having a second polarity opposite the first polarity to the conductor when the brake is disengaged weakens the magnetic circuit thereby allowing the spring to move the armature plate in the first axial direction away from the field shell and towards the friction plate to engage the brake.

2. The brake of claim 1 wherein a magnitude of the second current pulse is less than a magnitude of the first current pulse.

3. The brake of claim 1 wherein the at least one of the armature plate and the field shell has a content of at least 0.35 percent by weight of carbon or a carbon equivalent.

4. The brake of claim 3 wherein both of the armature plate and the field shell have a content of at least 0.35 percent by weight of carbon or a carbon equivalent.

5. The brake of claim 1 wherein said pressure plate is coupled to said field shell.

6. The brake of claim 1 wherein said spring is disposed between said field shell and said armature plate.

7. A brake, comprising:

a friction plate configured for coupling to a shaft for rotation with the shaft about an axis of rotation;

a pressure plate disposed about the axis on a first side of the friction plate and fixed against rotation;

an armature plate disposed about the axis on a second side of the friction plate;

a field shell disposed about the axis on an opposite side of the armature plate relative to the friction plate;

a spring biasing the armature plate in a first axial direction towards the friction plate and away from the field shell to engage the brake; and

,

a conductor disposed within the field shell

a controller configured to

deliver a first current pulse to the conductor when disengaging the brake, the first current pulse having a first polarity and configured to establish an electromagnetic circuit including the armature plate and the field shell that urges the armature plate in a second axial direction away from the friction plate and towards the field shell, a magnetic circuit including the armature plate and the field shell maintained after termination of the first current pulse due to a remanence in at least one of the armature plate and the field shell, the magnetic circuit generating an attractive force greater than a biasing force of the spring; and

,

deliver a second current pulse to the conductor when engaging the brake, the second current pulse having a second polarity opposite the first polarity and configured to weaken the magnetic circuit thereby allowing the spring to move the armature plate in the first axial direction away from the field shell and towards the friction plate.

8. The brake of claim 7 wherein a magnitude of the second current pulse is less than a magnitude of the first current pulse.

9. The brake of claim 7 wherein the at least one of the armature plate and the field shell has a content of at least 0.35 percent by weight of carbon or a carbon equivalent.

10. The brake of claim 9 wherein both of the armature plate and the field shell have a content of at least 0.35 percent by weight of carbon or a carbon equivalent.

11. The brake of claim 7 wherein said pressure plate is coupled to said field shell.

12. The brake of claim 7 wherein said spring is disposed between said field shell and said armature plate.

13. A brake, comprising:

a friction plate configured for coupling to a shaft for rotation with the shaft about an axis of rotation;

a pressure plate disposed about the axis on a first side of the friction plate and fixed against rotation;

an armature plate disposed about the axis on a second side of the friction plate;

a field shell disposed about the axis on an opposite side of the armature plate relative to the friction plate;

a spring biasing the armature plate in a first axial direction towards the friction plate and away from the field shell to engage the brake; and

,

a conductor disposed within the field shell

wherein at least one of the armature plate and the field shell has a remanence that generates, after the brake is disengaged by providing a current pulse to the conductor and following termination of the current pulse, an attractive force between the armature plate and the field shell greater than a biasing force of the spring.

14. The brake of claim 13 wherein the at least one of the armature plate and the field shell has a content of at least 0.35 percent by weight of carbon or a carbon equivalent.

15. The brake of claim 13 wherein both of the armature plate and the field shell have a content of at least 0.35 percent by weight of carbon or a carbon equivalent.