# US 11,441,626 B2 · Electric linear actuator and electric brake device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,626 B2 - Document ID: US11441626B2 - Status: Granted - Kind: B2 - Application number: 16/517,065 - Filed: 2019-07-19 - Published: 2019-11-07 - Granted: 2022-09-13 - Earliest claimed: 2017-01-26 - Assignees: Ntn Corporation - Applicants: Ntn Corporation - Inventors: Yui Masuda - Web page: https://patentgrep.com/patent/US11441626B2 ## CPC - B60T 13/741: {acting on an ultimate actuator} - F16D 65/18: adapted for drawing members together {, e.g. for disc brakes} - B60T 8/32: responsive to a speed condition, e.g. acceleration or deceleration ({using electrical circuitry or regulation means B60T8/17} ; B60T8/28 takes precedence; electric devices on electrically propelled vehicles indicating the wheel slip B60L3/10; measuring linear or angular speed per se G01P3/00) - H02K 7/06: Means for converting reciprocating motion into rotary motion or vice versa - H02K 7/102: with friction brakes - H02P 15/00: Arrangements for controlling dynamo-electric brakes or clutches (vector control H02P21/00) - H02P 27/04: using variable-frequency supply voltage, e.g. inverter or converter supply voltage - F16D 2066/005: {Force, torque, stress or strain} - F16D 2121/24: using motors - H02P 2201/07: DC-DC step-up or step-down converter inserted between the power supply and the inverter supplying the motor, e.g. to control voltage source fluctuations, to vary the motor speed - H02P 2201/09: Boost converter, i.e. DC-DC step up converter increasing the voltage between the supply and the inverter driving the motor - 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 - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract Provided is an electric linear motion actuator that enables size reduction and cost reduction while increasing the instantaneous output of an electric motor. A control device (2) of the electric linear motion actuator includes: a motor driver (24) configured to control power supplied to a coil (4b) of an electric motor (4); a power storage unit (21) connected to a power supply device (3) and the motor driver (24); a current flow direction restriction unit (20) disposed between the power supply device (3) and the power storage unit (21), which causes current to pass only in a direction in which power is supplied from the power supply device (3); and a step-up unit (19) configured to step up voltage of the power supply device (3) and provide the stepped-up voltage to the power storage unit (21). ## Claims ### Claim 1 An electric linear motion actuator comprising: an electric motor; a linear motion mechanism configured to convert rotational motion of the electric motor into linear motion of a linear motion unit via a rotation input/output shaft; and a control device connected to a power supply device for DC power, the control device being configured to drive the electric motor, wherein the control device includes, a motor driver configured to control power to be supplied to a coil of the electric motor, a power storage unit connected between the power supply device and the motor driver, a current flow direction restriction unit disposed between the power supply device and the power storage unit, the current flow direction restriction unit being configured to cause current to pass only in a direction in which power is supplied from the power supply device, and a step-up unit configured to step up voltage from the power supply device and provide the stepped-up voltage to the power storage unit, wherein the step-up unit includes: a constant current restriction section configured to restrict, when output current to be outputted from the step-up unit is greater than a set value, the output current to the set value or smaller; and a constant voltage restriction section configured to cause the step-up unit to output predetermined voltage when the output current to be outputted from the step-up unit is less than or equal to the set value, and wherein output power, of the step-up unit, restricted by the constant current restriction section or the constant voltage restriction section is smaller than maximum power, the maximum power being the largest consumption power of the electric motor. ### Claim 2 (depends on 1) The electric linear motion actuator as claimed in claim 1, wherein the power storage unit is a capacitor. ### Claim 3 (depends on 1) An electric brake apparatus comprising: the electric linear motion actuator as claimed in claim 1; a brake rotor linked to and rotate with a wheel; and a friction member configured to be brought into contact with the brake rotor so as to generate braking force, wherein the linear motion mechanism includes a friction member actuator, the friction member actuator being configured to convert the output of the electric motor into pressing force of the friction member, and the control device drives the electric motor so as to control the braking force, the braking force being generated when the friction member is brought into contact with the brake rotor. ### Claim 4 (depends on 3) The electric brake apparatus as claimed in claim 3, the electric brake apparatus further comprising a vehicle speed estimation device configured to estimate a speed of a vehicle to which the electric brake apparatus is mounted, wherein, in a case where the speed estimated by the vehicle speed estimation device falls within a predetermined range, the control device sets output voltage from the step-up unit so as to increase as the estimated speed increases. ### Claim 5 An electric linear motion actuator comprising: an electric motor; a linear motion mechanism configured to convert rotational motion of the electric motor into linear motion of a linear motion unit via a rotation input/output shaft; and a control device connected to a power supply device for DC power, the control device being configured to drive the electric motor, wherein the control device includes, a motor driver configured to control power to be supplied to a coil of the electric motor, a power storage unit connected between the power supply device and the motor driver, a current flow direction restriction unit disposed between the power supply device and the power storage unit, the current flow direction restriction unit being configured to cause current to pass only in a direction in which power is supplied from the power supply device, and a step-up unit configured to step up voltage from the power supply device and provide the stepped-up voltage to the power storage unit, the electric linear motion actuator further comprising: an angle estimation device configured to estimate a rotation angle of the electric motor; and an angular speed estimation unit configured to estimate an angular speed of the electric motor based on the rotation angle estimated by the angle estimation device, wherein the control device further includes, a voltage estimation unit configured to estimate voltage of the power storage unit, and an electric motor output restriction section configured to restrict an output for the electric motor based on the angular speed estimated by the angular speed estimation unit, the electric motor output restriction section being configured to set a maximum output for the electric motor to be larger when the voltage estimated by the voltage estimation unit is larger. ### Claim 6 (depends on 5) The electric linear motion actuator as claimed in claim 5, wherein the power storage unit is a capacitor. ### Claim 7 (depends on 5) An electric brake apparatus comprising: the electric linear motion actuator as claimed in claim 5; a brake rotor linked to and rotate with a wheel; and a friction member configured to be brought into contact with the brake rotor so as to generate braking force, wherein the linear motion mechanism includes a friction member actuator, the friction member actuator being configured to convert the output of the electric motor into pressing force of the friction member, and the control device drives the electric motor so as to control the braking force, the braking force being generated when the friction member, and the control device drives the electric motor so as to control the braking force, the braking force being generated when the friction member is brought into contact with the brake rotor.