Ntn Corporation

Fujifilm Corporation

Makoto Muramatsu

Tatsuya Yamasaki

Masaaki Eguchi

Yui Masuda

Kensuke Morita

Tomomi Goto

Makoto Yasui

Yuki Saoyama

Yuuki Saoyama

Koji Wariishi

Takayuki Norimatsu

Kazutaka Takahashi

Takayuki Kawamura

Tomoya Sakaguchi

Akira Asano

Naota Yamamoto

Mitsuo Kawamura

Kouji Tonohara

Tomoaki Goto

Norihide Sato

Hikaru Ishida

Ikuo Fujiniwa

Ken Horiuchi

Daisuke Kunimatsu

Koushirou Fujimoto

Yoshihisa Shibuya

Shinichi Yoshioka

An electric brake device includes an electric motor; a braking force application mechanism configured to apply a braking force on a vehicle wheel; a lock mechanism configured to assume one of a locked condition; a temperature sensor configured to measure an ambient temperature of a vehicle; and a freezing preventive power supply unit configured to initiate supply of an electric power to the electric motor or a drive source of the lock mechanism. The freezing preventive power supply unit interrupts the supply of the electric power to the electric motor or the drive source of the lock mechanism when the temperature detected by the temperature sensor exceeds a second preset temperature Tthat is higher than a first preset temperature T

Electric brake device

The electric linear motion actuator includes an electric motor, a drive shaft configured to be rotated by the electric motor, a rotation-to-linear motion converting mechanism configured to convert the rotational motion of the drive shaft to the axial linear motion of an axially movably supported outer ring member, and an electric locking mechanism incorporated in a reduction gear mechanism in which the rotation of a rotor shaft of the electric motor is reduced in speed and transmitted to the drive shaft. When the electric locking mechanism is energized, the power transmission path shifts to the locked state in which power cannot be transmitted, and when the electric locking mechanism is de-energized thereafter, the power transmission path is kept in the locked state. The electric locking mechanism is built in a motor case of the electric motor so that the electric motor and the electric locking mechanism are unitized.

Electric linear motion actuator and electric brake system

An electric linear motion actuator includes a locking mechanism for locking and unlocking the rotor shaft of an electric motor. The locking mechanism includes circumferentially arranged locking holes provided in a gear of a reduction gear mechanism, a locking pin moved toward and away from the locking holes, and engaged in one locking hole to lock the gear when the locking pin is moved toward the gear, and a linear solenoid for moving the locking pin toward and away from the gear. The plunger of the linear solenoid and the locking pin are formed as separate parts, and disposed coaxial with each other with their end faces axially facing each other. This prevents the moment load applied from the gear to the locking pin from acting on the plunger, thereby preventing damage to a bobbin slidably supporting the radially inner surface of the plunger.

The electric brake actuator with a parking function is provided with: detection unit which is provided in a vehicle in which the electric brake actuator is provided and is capable of detecting movement of the vehicle from a stop state; and determination unit configured to determine whether or not a locking mechanism has shifted to a parking locking state, by using a detection signal outputted from the detection unit, when the locking mechanism is driven by an actuator so as to switch from an unlocking state to the parking locking state.

Electric brake actuator with parking function

An electric linear motion actuator includes planetary rollers mounted between the radially inner surface of an outer ring member and the radially outer surface of a rotary shaft, and a carrier rotatable about the rotary shaft and including radially movable roller shafts rotatably supporting the respective planetary rollers. Elastic rings each having circumferentially separate ends are each wrapped around the roller shafts to radially inwardly bias the roller shafts, thereby bringing the respective planetary rollers into elastic contact with the radially outer surface of the rotary shaft. Each elastic ring is prevented from rotating relative to the roller shafts, thereby preventing one of the roller shafts from being axially aligned with the gap between the circumferential separate ends, causing the elastic ring to be radially compressed and thus making it impossible for the elastic rings to radially bias the roller shafts.

Electric linear motion actuator and electric disk brake system

A linear motion actuator includes an outer ring member mounted in a housing, a rotary shaft rotated by a motor, planetary rollers mounted between the outer ring member and the shaft and supported by a carrier rotatable about the shaft. A helical rib is formed on the inner surface of the outer ring member which is engaged in helical grooves formed in outer surfaces of the planetary rollers. When the shaft rotates, the planetary rollers rotate and revolve, thereby axially moving the outer ring member. Uneven axial loads applied to the planetary rollers from the outer ring member are supported by thrust bearings disposed between the planetary rollers and an inner disk of the carrier. Aligning seats are provided between each opposed pair of the planetary rollers and the thrust bearings such that the contact surfaces of the aligning seats shift relative to each other under the uneven axial loads.

A magnetic load sensor unit for use in a linear motion actuator is provided which is less likely to suffer from hysteresis errors during use while being mounted in the linear motion actuator, and which can reduce the axial length of the linear motion actuator. The magnetic load sensor unit is configured to detect the magnitude of an axial load applied to an object from the linear motion actuator. The sensor unit includes a flange member configured to be deflected when a reaction force to the axial load is received through a thrust bearing, a magnetic target which generates magnetic fields; and a magnetic sensor arranged such that its position relative to the magnetic target changes when the flange member is deflected. The flange member has an axial end surface in which a groove is formed with which rolling elements of the thrust bearing are in rolling contact.

Magnetic load sensor unit for use in a linear motion actuator, and linear motion actuator

An electric brake device includes an electric motor, a braking force application mechanism, a lock mechanism, a temperature sensor for measuring an ambient temperature of a vehicle in which the electric brake device is provided, and a freezing preventive power supply unit. The freezing preventive power supply unit initiates the supply of an electric power to the electric motor or a drive source of the lock mechanism in the event that while the braking force application mechanism applies a braking force and the lock mechanism is held in a locked condition, the temperature sensor detects a preset temperature of the electric brake device immediately before freezing.

An electric linear motion actuator includes: a rotary shaft to be driven by an electric motor; a plurality of planetary rollers kept in rolling contact with a cylindrical surface formed on an outer periphery of the rotary shaft; a carrier which retains the planetary rollers such that the planetary rollers are rotatable about axes thereof while revolving around the rotary shaft, and of which axial movement is restricted; and an outer ring member surrounding the planetary rollers and supported so as to be slidable in an axial direction. Helical ribs are formed on an inner periphery of the outer ring member; and circumferential grooves are formed on an outer periphery of each of the planetary rollers so as to be engaged with the helical ribs. A rotation of the rotary shaft is thus converted to a linear motion of the outer ring member.

Electric linear motion actuator

A parking brake has the function of monitoring a malfunction of the parking brake, thereby preventing accidents. The parking brake includes an electric motor and a linear motion mechanism which are connected together through a speed reduction mechanism. The parking brake further includes a locking pin which can be brought into engagement with the speed reduction mechanism by a solenoid. The parking brake further includes a monitor for detecting a change in reactance of the solenoid. Since the change in reactance as detected corresponds to a displacement of a plunger, it is possible to prevent accidents by monitoring deteriorated sliding properties of the locking pin based on the displacement detected.

Electric parking brake

An electric parking brake system includes an electric motor; a linear motion mechanism that converts the rotational movement of a rotor shaft of the electric motor to a linear movement of a slide member to operate a brake; a locking mechanism that fixes a position of the slide member; a control device that controls the electric motor and the locking mechanism; a brake load estimation unit that estimates a brake force; and an electric parking brake operation instruction device that is arbitrary operable. The control device automatically executes a parking brake operation when a stop state of the vehicle is detected even if the electric parking brake operation instruction device is not operated. The automatically applied parking brake force is set to a value smaller than the normal parking brake force applied by the parking brake operation instruction device.

Electric parking brake system

An electric linear motion actuator is provided which can set the clearance during normal braking operation of an electric brake system. The linear motion actuator includes a load sensor for detecting the magnitude of the load with which a friction pad is pressed against the brake disk, a temperature sensor for compensating for the influence of temperature on the load sensor, and an electronic control unit. The electronic control unit is adapted to calculate a target rotational angle from the position of the electric motor corresponding to the magnitude of the load detected by the load sensor to the position of the electric motor where the clearance is at a predetermined value, and control the electric motor to rotate the electric motor by the target rotational angle.

A disk brake system includes a disk, brake pads, and a linear motion actuator including an electric motor, a rotary shaft coupled to the motor through a reduction gear mechanism, planetary rollers formed with helical grooves in their outer surfaces, and an outer ring member having a helical rib engaged in the helical grooves. The outer ring is coupled to one of the brake pads. When the rotary shaft is rotated by the motor, the outer ring member is moved axially through the planetary rollers, and the brake pads are pressed against the disk. The linear motion actuator further includes a locking mechanism including engaging holes formed in an intermediate gear of the reduction gear mechanism at equal intervals, a locking pin, and a linear solenoid for moving the locking pin until the pin engages in one of the engaging holes, thus locking the motor.

An electric brake system is proposed which includes an electric linear motion actuator and can generate the required braking force with high accuracy. A load sensor () is provided in a motion converting mechanism of the actuator which converts the rotary motion of a rotary shaft () to which the rotation of an electric motor () is transmitted to linear motion of an outer ring member () as an output member. The load sensor () detects the pushing force with which the outer ring member () linearly drives a driven member. With this arrangement, if the driven member is a braking member of an electric brake system, it is possible to directly detect the braking force applied by the driven member and thus to accurately generate the required braking force.

Growing community of inventors

Shizuoka, Japan

Makoto Muramatsu