Electric actuator for S-cam brake

Patent metadata

Field	Value
Publication number	US-10001186-B2
Application number	US-201615248636-A
Country	US
Kind code	B2
Filing date	Aug 26, 2016
Priority date	Aug 26, 2016
Publication date	Jun 19, 2018
Grant date	Jun 19, 2018

Abstract

A drum brake assembly includes a brake spider having a central aperture configured to receive an axle extending therethrough and first and second brake shoes. Each of the first and second brakes shoes has a first end pivotally coupled to the brake spider. First and second cam followers are disposed at corresponding second ends of the first and second brake shoes. A camshaft has a shaft extending through a camshaft aperture in the brake spider and disposed along a rotational axis and a cam disposed at a first end of the shaft and in engagement with the first and second cam followers. An electric motor has an output shaft coupled to the camshaft. A controller is configured to drive the electric motor to cause rotation of the camshaft and move the first and second brake shoes between positions of engagement and disengagement with an associated braking surface.

First claim

What is claimed is:

1. A brake actuator assembly comprising:
a camshaft associated with a brake assembly, the camshaft having a receiving end and an actuating end, wherein the camshaft is in a first axis;
an electric motor having an output shaft, the output shaft having a motor end and a transmitting end, wherein the output shaft is in a second axis and the second axis is oriented 90 degrees from the first axis;
a drive mechanism, wherein the drive mechanism is coupled to the receiving end of the camshaft and the transmitting end of the electric motor, the drive mechanism having a first mode and second mode of operation, and
a controller configured to drive the electric motor to cause rotation of the camshaft to actuate the brake assembly via the drive mechanism, wherein the drive mechanism is driven in the second mode when the controller is capable of identifying an increase in torque in the electric motor by identifying an increase in current required by the electric motor.

2. The brake actuator assembly as in claim 1 , wherein a first mode of operation of the electric motor is a high speed, low force mode and a second mode of operation of the electric motor is a low speed, high force mode.

3. The brake actuator assembly as in claim 2 , wherein the controller places the electric motor in the first mode of operation of the electric motor until the increase in torque is identified.

4. The brake actuator assembly of claim 1 wherein the controller is configured to:
receive a command indicative of a desired brake force; and,
transmit a control signal corresponding to the desired brake force to the electric motor, the control signal configured to cause rotation of the camshaft over a distance corresponding to the desired brake force.

5. An actuator for a brake assembly, comprising:
an electric motor having an output shaft configured for coupling to an associated camshaft of the brake assembly wherein the camshaft is in a first axis and the output shaft is in a second axis, the second axis being oriented 90 degrees from the first axis; and,
a controller configured to drive the electric motor to cause rotation of the output shaft, the controller configured to:
receive a command indicative of a desired brake force;
transmit a control signal to the electric motor, the control signal configured to cause the brake assembly to actuate;
monitor a level of current required by the electric motor;
determine, responsive to the level of current, whether a brake force applied corresponds to the desired brake force; and,
maintain the applied brake force applied at the desired brake force.

6. The actuator of claim 5 wherein the controller is further configured, in determining when the brake assembly is actuated, to identify an increase in torque in the electric motor.

Assignees

• Bendix Spicer Foundation Brake

Inventors

• Kasper Phillip J
• Hutchins Christopher H
• Salvatora Randy J
• Szudy James E

Classifications

• F16D2125/52

  with non-parallel stationary axes, e.g. worm or bevel gears · CPC title

• F16D2121/24

  using motors · CPC title

• F16D65/22 Primary

  adapted for pressing members apart {, e.g. for drum brakes} · CPC title

• F16D2125/30

  acting on two or more cam followers, e.g. S-cams · CPC title

• F16D51/28

  mechanically actuated · CPC title