Electromechanical actuator for vehicle brake and braking system comprising such an actuator

Patent metadata

Field	Value
Publication number	US-9638278-B2
Application number	US-201414541801-A
Country	US
Kind code	B2
Filing date	Nov 14, 2014
Priority date	Nov 20, 2013
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

The invention relates to an electromechanical actuator for a vehicle brake comprising a body ( 4 ) in which are arranged an electric motor ( 5 ) and a threaded plunger cooperating via a helical link with a nut ( 8 ) driven in rotation by the electric motor ( 5 ). According to the invention, the nut ( 8 ) is mounted to move axially in the body ( 4 ) of the actuator between a rest position towards which the nut ( 8 ) is pushed back by elastic means, and an active position towards which the nut is displaced against the elastic means when a braking force is applied, the actuator further comprising means for detecting the axial displacement of the nut.

First claim

The invention claimed is:

1. An electromechanical actuator for vehicle brake comprising:
a body ( 4 ) in which are arranged an electric motor ( 5 ) and a plunger ( 6 ) mounted to slide along a sliding axis (X) by protruding from the body ( 4 ) of the actuator so as to selectively apply a braking force onto friction members ( 2 ) of the brake, the plunger being threaded and cooperating via a helical link with a nut ( 8 ) driven in rotation by the electric motor ( 5 ),
wherein the nut ( 8 ) is mounted to move axially in the body ( 4 ) of the actuator between a rest position towards which the nut ( 8 ) is pushed back by elastic means, and an active position towards which the nut is displaced against the elastic means when a braking force is applied, the actuator further comprising means for detecting the axial displacement of the nut,
wherein the elastic means comprise a calibrated compression spring ( 27 ) extending between the body ( 4 ) and a bearing plate ( 20 ) which extends around the nut by being secured axially to the nut ( 8 ) while being free in rotation with respect to the nut,
wherein the detection means comprise at least one contactor ( 30 ) suitable for detecting an axial displacement of the bearing plate ( 20 ), and
wherein the at least one contractor comprises a plurality of contactors ( 30 ) distributed in a first network ( 43 ) of contactors ( 30 ) connected in parallel and a second network ( 44 ) of contactors ( 30 ) connected in parallel.

2. A braking system of a vehicle comprising at least one wheel equipped with a brake provided with an electromechanical actuator according to claim 1 , the braking system further comprising control means ( 40 ) connected to the actuator and comprising electrical measurement means ( 41 ) connected to the contactor and suitable for detecting whether a braking force is actually applied by the actuator.

3. The braking system of a vehicle according to claim 2 , in which the measurement means comprise a first measurement resistor ( 48 ) connected to the first network ( 43 ) of contactors ( 30 ) and a second measurement resistor ( 49 ) connected to the second network ( 44 ) of contactors ( 30 ).

4. The braking system of a vehicle according to claim 3 , in which the control means ( 40 ) are suitable for detecting a fault on one of the networks of contactors when the voltages measured by the measurement means at the terminals of the first measurement resistor ( 48 ) and of the second measurement resistor ( 49 ) are different.

5. The braking system of a vehicle according to claim 4 , in which the control means ( 40 ) are suitable for detecting an open circuit fault on one of the networks or a fault of a holding spring ( 33 ) arranged to keep a contactor ( 30 ) in closed position when no braking force is applied.

6. The electromechanical actuator according to claim 1 , in which the bearing plate ( 20 ) bears via an abutment against a toothed wheel secured to the nut.

7. The electromechanical actuator according to claim 6 , in which the abutment is a thrust ball bearing.

Assignees

• Messier Bugatti Dowty
• Messier-Bugarri-Dowty

Inventors

• Selles Franck
• Evenor Eric
• Richard Nathanael

Classifications

• B60T13/741

  acting on an ultimate actuator · CPC title

• F16D2125/48

  with parallel stationary axes, e.g. spur gears · CPC title

• F16D2066/006

  without direct measurement of the quantity monitored, e.g. wear or temperature calculated form force and duration of braking · CPC title

• F16D65/18

  adapted for drawing members together {, e.g. for disc brakes} · CPC title

• B64C25/44

  Actuating mechanisms · CPC title