# US 9,501,063 B2 · Electric linear motion actuator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,501,063 B2 - Document ID: US9501063B2 - Status: Granted - Kind: B2 - Application number: 14/648,722 - Filed: 2013-11-12 - Published: 2015-11-05 - Granted: 2016-11-22 - Earliest claimed: 2012-12-03 - Assignees: Ntn Corporation - Applicants: Yui Masuda - Inventors: Yui Masuda - Web page: https://patentgrep.com/patent/US9501063B2 ## CPC - G05D 3/12: using feedback - F16D 65/18: adapted for drawing members together {, e.g. for disc brakes} - G05B 19/19: characterised by positioning or contouring control systems, e.g. to control position from one programmed point to another or to control movement along a programmed continuous path - H02K 7/06: Means for converting reciprocating motion into rotary motion or vice versa - H02K 11/24: Devices for sensing torque, or actuated thereby (H02K11/27 takes precedence) - H02P 3/26: by combined electrical and mechanical braking - H02P 6/006: {Controlling linear motors} - H02P 6/16: Circuit arrangements for detecting position - F16D 2121/24: using motors - F16D 2125/40: Screw-and-nut - F16D 2125/50: with parallel non-stationary axes, e.g. planetary gearing - F16D 2127/06: Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms - F16D 2129/08: Electromagnets - F16H 25/20: Screw mechanisms (with automatic reversal F16H25/12) - G05B 2219/43194: Speed steps, switch over as function of position - G05B 2219/49141: Detect near collision and slow, stop, inhibit movement tool - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES - F16D: COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - 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 - F16H: GEARING ## Abstract An electric linear motion actuator includes an electric motor, a motion converting mechanism that converts the rotational motion of the electric motor into a linear motion of a linear moving member, a load sensor that detects the magnitude of the load applied to the brake disk from the linear moving member, and a controller that performs feedback control on the electric motor based on the difference between the load detected by the load sensor and a load command value. The controller reduces the number of revolutions of the electric motor when the linear moving member moves into a predetermined zone immediately before the position where the clearance between the linear moving member and the brake disk becomes zero. ## Claims ### Claim 1 An electric linear motion actuator comprising: an electric motor; a linear moving member capable of moving between a standby position where the linear moving member is spaced apart from a target with a predetermined clearance between the linear moving member and the target and a load applying position where the linear moving member contacts the target to apply a load to the target; a motion converting mechanism that converts a rotational motion of the electric motor into a linear motion of the linear moving member; a load sensor that detects a magnitude of the load applied to the target from the linear moving member; and a controller configured to perform a feedback control in which based on a difference between the load detected by the load sensor and a load command value, the electric motor is controlled so that the load applied from the linear moving member to the target becomes equal to the load command value, wherein the controller comprises an overshoot suppression control means configured to reduce a number of revolutions of the electric motor when the linear moving member moves from the standby position toward the load applying position to apply a load to the target and moves into a predetermined zone immediately before the position where the clearance between the linear moving member and the target becomes zero. ### Claim 2 (depends on 1) The electric linear motion actuator of claim 1, further comprising a rotation angle sensor that detects a rotation angle of the electric motor; wherein the overshoot suppression control means is configured to determine whether the linear moving member has moved into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero, on the basis of the rotation angle of the electric motor detected by the rotation angle sensor. ### Claim 3 (depends on 2) The electric linear motion actuator of claim 2, wherein the overshoot suppression control means is configured to calculate a range of the rotation angle of the electric motor corresponding to the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero, based on a magnitude of a predetermined load detected by the load sensor while the linear moving member is applying a load to the target, and with reference to a rotation angle of the electric motor detected by the rotation angle sensor when the magnitude of the predetermined load is detected by the load sensor; and the overshoot suppression control means is further configured to determine that the linear moving member has moved into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero, when the rotation angle of the electric motor detected by the rotation angle sensor moves within the range of the rotation angle. ### Claim 4 (depends on 1) The electric linear motion actuator of claim 1, wherein the overshoot suppression control means is configured to change a voltage applied to the electric motor such that the number of revolutions of the electric motor decreases, when the linear moving member moves into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero. ### Claim 5 (depends on 1) The electric linear motion actuator of claim 1, wherein the overshoot suppression control means is configured to reduce a voltage to be applied to the electric motor to a predetermined value, when the linear moving member moves into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero. ### Claim 6 (depends on 1) The electric linear motion actuator of claim 1, wherein the overshoot suppression control means is configured to perform feedback control on the electric motor in which based on a difference between the number of revolutions of the electric motor and a predetermined small number of revolutions, the number of revolutions of the electric motor is reduced to the predetermined small number of revolutions, when the linear moving member moves into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero. ### Claim 7 (depends on 1) The electric linear motion actuator of any one of claim 1, wherein the electric motor is configured to be driven by a pulse voltage generated by repeatedly and discontinuously applying a constant voltage; and the overshoot suppression control means is configured to reduce a ratio of a turned-on time during which the constant voltage is being applied to a sum of the turned-on time and a turned-off time during which the constant voltage is not being applied, when the linear moving member moves into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero. ### Claim 8 (depends on 1) The electric linear motion actuator of claim 1, wherein the electric motor is driven by a pulse voltage generated by being repeatedly turned on and turned off; and the overshoot suppression control means is configured to reduce a pulse amplitude of the pulse voltage, which is applied to the electric motor, when the linear moving member moves into the predetermined zone, which is immediately before the position where the clearance between the linear moving member and the target becomes zero.