# US 10,479,342 B2 · Electrically powered brake device

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- Number: US 10,479,342 B2
- Document ID: US10479342B2
- Status: Granted
- Kind: B2
- Application number: 15/825,936
- Filed: 2017-11-29
- Published: 2018-03-22
- Granted: 2019-11-19
- Earliest claimed: 2015-06-01
- Assignees: Ntn Corporation
- Applicants: Ntn Corporation
- Inventors: Yui Masuda; Tatsuya Yamasaki
- Web page: https://patentgrep.com/patent/US10479342B2

## CPC

- B60T 17/221: {Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems (hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M)}
- B60T 7/042: {by electrical means, e.g. using travel or force sensors}
- B60T 8/171: Detecting parameters used in the regulation; Measuring values used in the regulation
- B60T 8/172: Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters {(B60T8/17551 takes precedence)}
- B60T 8/3255: {Systems in which the braking action is dependent on brake pedal data}
- B60T 13/74: with electrical assistance or drive
- B60T 13/741: {acting on an ultimate actuator}
- B60T 17/22: Devices for monitoring or checking brake systems; Signal devices
- F16D 55/00: Brakes with substantially-radial braking surfaces pressed together in axial direction, e.g. disc brakes (similar clutches F16D13/38)
- F16D 55/226: in which the common actuating member is moved axially {, e.g. floating caliper disc brakes}
- F16D 65/18: adapted for drawing members together {, e.g. for disc brakes}
- F16D 65/183: {with force-transmitting members arranged side by side acting on a spot type force-applying member}
- F16D 66/00: Arrangements for monitoring working conditions, e.g. wear, temperature
- B60T 2220/04: Pedal travel sensor, stroke sensor; Sensing brake request
- F16D 2066/005: {Force, torque, stress or strain}
- F16D 2121/24: using motors
- F16D 2125/40: Screw-and-nut
- F16D 2125/50: with parallel non-stationary axes, e.g. planetary gearing
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES

## Abstract

The electric brake device includes an electric motor, a friction member operator, a friction member, a brake rotor, and a control device. A braking force estimator provided in the control device includes: a direct estimator configured to convert output of a braking force sensor which detects a load or displacement corresponding amount, to a braking force; and an indirect estimator configured to estimate the braking force on the basis of information other than output of the braking force sensor. A range in which the braking force is estimated by the direct estimator is a specified low-braking-force range, and in a range beyond this range, estimation of the braking force is performed by the indirect estimator.

## Claims

### Claim 1

An electric brake device comprising:
a brake rotor;
a friction member;
a friction member operator configured to bring the friction member into contact with the brake rotor;
an electric motor configured to drive the friction member operator;
a rotation angle estimator configured to estimate a motor rotation angle of the electric motor;
a braking force estimator configured to estimate a braking force; and
a control device configured to control the braking force by use of the electric motor so as to achieve a target braking force,
wherein the braking force estimator includes:
a direct estimator configured to convert, into an estimated braking force, output of a braking force sensor which detects a load or displacement corresponding amount acting on one of the friction member, the friction member operator, and a member supporting the friction member or the friction member operator; and
an indirect estimator configured to estimate the braking force on the basis of information other than the output of the braking force sensor, and
wherein a range below a predetermined threshold value in which the braking force is only estimated by the direct estimator is a specified low-braking-force range, and in a specified high-braking-force range above the predetermined threshold value and beyond the specified low-braking-force range, estimation of the braking force is only performed by the indirect estimator.

### Claim 2 (depends on 1)

The electric brake device as claimed in claim 1, wherein
the indirect estimator estimates the braking force, using a specified relationship between the motor rotation angle and the braking force, on the basis of the motor rotation angle detected by the rotation angle estimator.

### Claim 3 (depends on 1)

The electric brake device as claimed in claim 1, wherein
the indirect estimator estimates the braking force, using a specified relationship between motor current of the electric motor and the braking force, on the basis of a value of the motor current detected by a current sensor.

### Claim 4 (depends on 1)

The electric brake device as claimed in claim 1, wherein
the braking force sensor detects an amount of displacement of one of the friction member, the friction member operator, and the member supporting the friction member or the friction member operator due to a contact force between the friction member and the brake rotor.

### Claim 5 (depends on 1)

The electric brake device as claimed in claim 1, further comprising a calibrator configured to perform calibration for the indirect estimator on the basis of a relationship between the estimated braking force estimated by the direct estimator and at least one of the motor rotation angle and motor current of the electric motor.

### Claim 6 (depends on 5)

The electric brake device as claimed in claim 5, wherein
when a speed of a vehicle to which the electric brake device is mounted is equal to or smaller than a predetermined value, the electric motor is activated not depending on a command from an operator of the vehicle, and calibration for the indirect estimator is performed on the basis of the calibrator.