Abstract: The invention relates to an electromechanical disk brake which has a switchable freewheel in order to be configured as a parking brake. The switchable freewheel includes a clamping roller freewheel having rollers for locking a motor shaft of an electric motor of the brake. A locating bearing of the motor shaft of an electric motor, and the freewheel are accommodated on a cover of a housing of the electric motor, and all the electric connections of the disc brake are routed via the cover. The number of components used can be reduced considerably by the integrated design. Moreover, the positional tolerances of the freewheel in relation to the motor shaft can be reduced with the aid of the invention.

Abstract: A brake, in particular for motor vehicles, has a friction member (1) which can be pressed an actuator (15) against or released from the friction face of an element (3) which is to be braked. The brake is equipped with a particularly simple and reliable readjustment device (7) and with an emergency release device (12), wherein the readjustment device has a spindle (9) which drives an adjustable element (8) which is connected thereto, and the emergency release device (12) has two cam disks (13, 14) which are rotatable relative to one another, one (14) of which cam disks is rotationally fixedly connected to the spindle (9).

Abstract: An aircraft electric brake actuator assembly includes an actuator housing, a motor housing, an actuator, an electric motor, and an actuator brake. The actuator housing is configured to be mounted on an aircraft landing gear. The motor housing is coupled to the actuator housing and is removable therefrom. The motor housing is also accessible when the actuator housing is mounted on an aircraft. The electric motor is disposed within the motor housing and is coupled to the actuator. The actuator brake is disposed within the motor housing and is removably coupled to the motor.

Abstract: In a vehicle disk brake, a motor housing houses in a housing recess a case into which an end of an output shaft liquid-tightly protrudes, and is mounted to a caliper body. A reduction mechanism having an output rotating member is sealed in the case while part of the output rotating member fluid-tightly protrudes from the case so as to be coaxially and operatively connected to a rear portion of the screw shaft. Grease is charged into the case. Thus, the case for housing the reduction mechanism is simply configured while preventing leakage of the grease charged into the case, and mounting of the case to the caliper body is facilitated.

Abstract: A slack adjustment system for a disk brake includes a biasing member to adjust slack in a brake system. The biasing member operates independently of pressure applied to a brake actuator. A locking member prevents adjustment when adjustment is not necessary. Release of the locking member allows the biasing member to adjust a resting position of brake pads independent of driver applied brake pressure.

Abstract: A motor-driven parking brake apparatus includes a load sensor (pressure sensor) for detecting axial load of a screw shaft. The pressure sensor includes a transmission member which receives the axial load via a circular surface of a plate, and a casing which accommodates the transmission member and receives the axial load via the transmission member. This casing has a circular opening having an opening area smaller than the surface of the circular surface. The pressure sensor detects a pressure generated due to a load received from an exposed portion of the transmission member which is exposed from the circular opening. Due to characteristics of the transmission member, the load received from the exposed portion is a portion of the axial load and proportional to the axial load.

Abstract: A hydraulic modulator includes a cylinder for slidably supporting a power piston and changing the volume of a hydraulic chamber communicating with brake calipers according to the sliding of the power piston, and an electric motor for sliding the power piston through a power transmitting mechanism. The cylinder extends parallel to a rotating shaft, and a rotational motion of the electric motor is converted into a linear motion on an axis parallel to the rotating shaft. The power transmitting mechanism is provided by a ball screw mechanism composed of a ball screw nut, balls, and a ball screw shaft for converting the rotational motion of the electric motor into the linear motion of the push slider. The push slider has a head portion coming into spherical contact with the power piston. The hydraulic modulator so configured has a small size, and an improved arrangement of components.

Abstract: A disc brake with a rotatable and axially displaceable shaft for actuation, and with an actuating element. Further, a sealing means with a sealing portion is provided, which acts elastically on an associated sealing surface, with the sealing portion closing a slot between the sealing surface and the housing for sealing purposes and abutting on a stop. The stop, the sealing surface and the actuating element are designed integrally. This measure allows significantly reducing the production costs because the complexity of components is decreased and the assembly is thus simplified.

Abstract: An electro-mechanical brake achieves a safe traveling and braking with a high accuracy device for detecting a piston position at which a brake pad and a disk rotor contact each other. A pad contact position detecting device in which an electric circuit is not formed to prevent an electric current from flowing therethrough when a pad pressing force is not generated and the electric circuit is formed to enable the electric current to flow therethrough when the pad pressing force is generated is applied to the electro-mechanical brake. A pad contact position can thereby be detected accurately.

Abstract: Provided are a cable-driving apparatus that performs the function of an equalizer using a planet gear assembly, and a parking brake system using the cable-driving apparatus. The cable-driving apparatus includes a driving motor; a first planet gear assembly for reducing a rotational velocity of the driving motor; and a second planet gear assembly coupled to the first planet gear assembly, wherein a first parking brake cable is connected to a circumferential outer surface of a ring gear of the second planet gear assembly, and a second parking brake cable is connected to a circumferential outer surface of a carrier of the second planet gear assembly in an opposite direction to the first parking brake cable.

Abstract: An electric direct-acting actuator is proposed which can maintain a large power increasing function without mounting a separate speed reducer. A plurality of planetary rollers (7) are disposed between the radially outer surface of a rotor shaft (5) of an electric motor and the radially inner surface of an outer ring member (1) fixed in position around the rotor shaft (5) so as to be rotatable about the rotor shaft (5) and about their own axes when the rotor shaft (5) rotates. A helical rib is defined by a rib member (9) engaged in a helical groove (8) formed in the radially inner surface of the outer ring member (1). The helical rib is engaged in circumferential grooves (10) formed in the radially outer surface of each planetary roller (7) at the same pitch as the turns of the helical rib. Thus, the rotary motion of the rotor shaft (5) is converted to a linear motion of the planetary rollers (7), so that it is possible to ensure a large power increasing function without mounting a separate speed reducer.

Abstract: An actuating system 1 for a wheel brake system of a motor vehicle, wherein the braking action is obtained by means of a rotatable cam element 2 fixed to the motor shaft 8 of an electric motor, with said rotatable cam element 2 abutting against an actuating member 4, so as to laterally displace said actuating member 4, resulting in the braking pads 5 being pressed against the friction element or brake disk. Recovery or adjustment of the backlash or gap arising due to the wear of the brake pads. The motor-cam group or assembly is displaced so as to keep the brake pads 5 in light contact with the friction element or disk but without exerting any unwanted braking action.

Abstract: Apparatus including a brake control assembly having a brake fluid accumulator assembly. The brake fluid accumulator assembly includes a brake fluid orifice, at least one brake-fluid-accumulating piston bore, a controllable bi-directional motor, and at least one piston. The brake fluid orifice is fluidly connectable to a brake apply master cylinder and is fluidly connectable to a wheel brake. The at-least-one brake-fluid-accumulating piston bore is fluidly connected to the brake fluid orifice. The motor has a first motor driving direction and an opposite second motor driving direction. The at-least-one piston is each positioned in and slidable within a corresponding brake-fluid-accumulating piston bore and is each movable by the motor, in the first motor driving direction, to move in compression within the corresponding brake-fluid-accumulating piston bore.

Abstract: In an embodiment, an electric parking brake system is disclosed. The system may include or comprise a pair of parking cables each connected to a brake. Additionally, the system may include or comprise a motor and a drive gear. The system may also include or comprise a planetary gear unit including or comprising a sun gear connected to the drive gear, a plurality of planetary gears gearedly connected with the sun gear, an internal gear formed along a revolving path of the planetary gears, and an output carrier connected to the planetary gears. The system may further include or comprise a screw-nut unit including a screw member and a nut member screwed to the screw member, the screw-nut unit being connected to the output carrier, and the parking cables being connected to opposite ends of the screw-nut unit, respectively.

Abstract: An electric parking brake including a housing, an actuator, a gear box assembly, a driven gear, a spindle, a screw nut, an equalizer through which the spindle is penetrated and the screw nut is rotatably inserted, brake cables connected to opposite sides of the equalizer, respectively, each brake cable having a first end formed with a coupling piece for the connection of the equalizer and a second end connected to an associated one of wheel brake devices, and an emergency release device including cam units and operating levers and adapted to slacken the brake cables in an emergency release situation, so as to release the parking brake. In the case of any emergency situation, such as electric discharge of a vehicle or failure of the parking brake, the parking brake is released by a simple cable pulling action.

Abstract: A disk brake with a parking brake mechanism capable of exerting a large piston thrust required for operating a parking brake, without adversely affecting operation of a service brake. A parking brake mechanism 32, which is driven by an electric motor provided outside a housing 30, is incorporated in a caliper 14 in which a piston 26 is slidably disposed in a cylinder 24. The parking brake mechanism 32 is slidably fitted via a seal member 36 into the piston 26 and provided with a nut member 37 that is prevented from rotating relative to the piston 26 by engagement of a pin 48 and a pin hole 49; and a shaft 35 that is screwed into the nut member 37. During a service brake operation, the piston 26 alone is moved by a hydraulic pressure under a small piston thrust.

Abstract: A combined service and parking brake apparatus, having a brake unit equipped with a brake disc and at least one brake pad in which a fluid pressure actuatable brake piston is able to place the brake pad against the brake disc and having a parking brake unit which includes an electric drive unit, a transmission, and a spindle unit equipped with a nut and spindle in order to mechanically lock the brake unit in a parking brake position, and in which the electric drive unit, the transmission, and the spindle unit are situated in series on a common axis.

Abstract: An electric disc brake including friction pads to press a disc, a carrier to support the friction pads, a caliper housing supported by the carrier to be movable back and forth so as to press the friction pads, and a pressing device to press the friction pads. The pressing device includes a pressing member mounted to the caliper housing and moved back and forth to thereby press and release any one of the friction pads, a screw axis connected to the pressing member, a drive shaft constituted by a worm wheel connected to the screw axis and a worm engaged with the worm wheel and mounted across the screw axis, and a motor rotating the drive shaft forward and backward.

Abstract: An electric brake comprises an actuator module including a module housing, a reciprocating ram, and an electric motor operatively connected to the reciprocating ram for selectively extending and retracting the reciprocating ram with respect to the module housing. The ram has an inner portion of non-circular cross-section and an outer portion of circular cross-sectional, and the housing has a guideway for the ram, which guideway has an inner portion of non-circular cross-section for interacting with the inner portion of the ram to prevent rotation of the inner portion of the ram, and an outer portion of circular cross-sectional. The actuator module can be equipped with a bi-stable holding brake having a first state permitting at least retraction of the ram and a second state preventing at least retraction of the ram.

Abstract: A disc brake for a vehicle, reduced in volume by improving a driving unit thereof that presses a wedge and therefore conveniently installed in the vehicle. The disc brake includes a disc rotated along with wheels of the vehicle, inner and outer friction pads disposed at both sides of the disc, a caliper housing supporting the outer friction pad, a wedge member disposed at a rear side of the inner friction pad and formed with inclined surfaces on a rear side thereof, a supporting member formed with inclined surfaces corresponding to the inclined surfaces of the wedge member and fixed to the caliper housing, and a driving unit operating the wedge member to perform a braking operation. The driving unit includes a screw axis, a driving motor, a worm gear constituted by a worm and a worm wheel, and a moving member.

Abstract: The invention relates to a regulating device, in particular a motor vehicle parking brake with a regulating unit having a power-operated drive. To provide a regulating device which enables simple cable balancing, it is proposed that a hollow shaft be moved against a torsionally resistant stop as a function of the spring force of an elastic element, when the parking brake is released. The axial position of the stop thus ensures that an adequate cable bias force is always present.

Abstract: An electric brake assembly includes an electric motor having a rotor in which a nut of a ball screw is fitted. A brake pad is coupled through a presser member to the threaded shaft of the ball screw. A bolt is threaded into the threaded shaft. A snap ring is mounted around a large-diameter portion of the bolt with its radially outer edge pressed against the radially inner surface of the rotor of the motor so that its radially outer portion is inclined obliquely rearwardly toward its radially outer edge. When the rotor is rotated in the forward rotational direction, the threaded shaft can move forwardly to press the brake pads against the disc rotor. When the motor is deactivated, the threaded shaft cannot retract after it has abutted the snap ring because the snap ring cannot move rearwardly relative to the rotor.

Abstract: The invention relates to a brake device for braking a moving brake body (2) by means of pressing a brake element (3, 4) onto the brake body (2), wherein a conversion device (7) is provided for converting a rotational movement of a brake drive shaft (9) into a translational movement of the brake element (4) in the direction of the brake body (2), wherein a rotary percussion mechanism (8) is connected between the brake drive shaft (9) and the conversion device (7).

Abstract: An electric disk brake for a vehicle, includes an electric motor in which a brush coming into slide contact with a commutator provided on an output shaft rotatably supported in a motor housing is held by a brush holder secured to the motor housing, and a rotation angle detection sensor for detecting a rotation angle of the electric motor. A brake piston driven by the electric motor is slidably fitted to a caliper body. A detected portion to be detected by the rotation angle detection sensor housed and placed in the motor housing is provided on the output shaft in the motor housing. Thus, the rotation angle detection sensor can be provided without any special waterproof seal and with a reduced number of components.

Abstract: An electric brake actuator for the brake system of an aircraft is presented. A brake actuator includes a piston driven by a cylindrical nut and screw arrangement, driven by an appropriate motor of the actuator. Application of brake force results in a reactionary force that deflects the top cover of the actuator. The axial component of this deflection correlates directly with the brake force applied. A beam is interposed between this cover and a top cap, such that deflection of the beam correlates to applied brake face. Piezo-resistive devices are connected to the beam and, through a whetstone bridge, provide an electrical output signal correlating to applied brake force.

Abstract: The present invention relates to an automatic parking brake, including a brake piston, an auxiliary piston, a hydraulic chamber disposed between the brake piston and the auxiliary piston, a spring element, for prestressing the auxiliary piston, a spindle device connected to the auxiliary piston via a threaded connection, and a drive for the spindle device, wherein in a locked state of the parking brake, the brake piston is mechanically locked via the spindle device and the spring-loaded auxiliary piston, and in a released state of the parking brake, the auxiliary piston is blocked by means of the spring element and/or by means of the spindle device.

Abstract: A harmonic drive linear actuator includes a first annular member defining a longitudinal axis and lying on a plane, which is perpendicular to the longitudinal axis. The first member is relatively flexible along a direction parallel to the plane. A second member is substantially coaxially aligned with the first member to define opposed substantially cylindrical surfaces and are fixed for non-relative rotation about the longitudinal axis. An actuator is provided for flexing the first annular member into at least two spaced-apart points of contact between the opposed surfaces and for sequentially flexing the first member to rotate the at least two points of contact circumferentially about the axis. The first and second surfaces define cooperating thread-forms thereon, which selectively engage to effect controlled, bidirectional relative axial displacement between the members in response to sequential flexure of the first member.

Abstract: A brake, in particular for motor vehicles, has a friction member (1) which can be pressed an actuator (15) against or released from the friction face of an element (3) which is to be braked. The brake is equipped with a particularly simple and reliable readjustment device (7) and with an emergency release device (12), wherein the readjustment device has a spindle (9) which drives an adjustable element (8) which is connected thereto, and the emergency release device (12) has two cam disks (13, 14) which are rotatable relative to one another, one (14) of which cam disks is rotationally fixedly connected to the spindle (9).

Abstract: A parking-brake operating mechanism is provided with an adjusting spindle, a cam shaft to which a parking lever is connected, and a thrust transmitting assembly disposed between the cam shaft and the adjusting spindle. The thrust transmitting assembly includes a rolling roller which can roll between the cam shaft and the adjusting spindle. Rolling curved surfaces are provided respectively at the cam shaft and the adjusting spindle. The rolling roller is disposed in contact with the rolling curved surfaces.

Abstract: According to the present invention, a cartridge assembly, which is inserted into an inner cylinder of a caliper housing and generates an axial force during parking braking, is fixed by a retainer outside caliper housing. Accordingly, a space occupying member for fixing is not provided in the inner cylinder of caliper housing, and for this reason, the inner cylinder can be more simply machined. Further, when air is discharged after the cartridge assembly is inserted into the caliper housing, air can smoothly flow in the inner cylinder of the caliper housing.

Abstract: A disc brake caliper for use with a disc brake rotor having a first side and a second side. The caliper further includes a first mounting portion and a second mounting portion each positioned adjacent one side of the disc brake rotor. The caliper further includes brake pads disposed adjacent the respective mounting portions such that brake pads are on opposite sides of the disc brake rotor and in facing relationship therewith. Further, the disc caliper includes a hydraulic service brake actuator and an electric parking brake actuator, each of which is operable independently of the other. Each of the actuators are arranged for actuation against a second side of the first brake pad for displacing the first brake pad away from the first mounting portion and into engagement with the disc brake rotor. The hydraulic service brake and the electric parking brake actuators have positions of actuation on the second side of the first brake pad at positions spaced apart.

Abstract: When a vehicle is suddenly stopped by turning off an ignition key switch on a way of a slope road, a braking force maintaining control is not preformed, and it often occurs that the vehicle moves down along the slope road. To prevent such occurrence, an electro-mechanical braking device for maintaining the braking force is provided so that the vehicle is parked securely. The electro-mechanical braking device includes a parking brake mechanism for maintaining the brake force even when an ignition key switch (power supply switch) of the vehicle is turned off. When the power supply switch (ignition key switch) of the vehicle is turned off with a braking pedal being stroked or a braking operation signal being present, the parking-brake mechanism is activated (the brake force is maintained).

Abstract: The invention relates to a brake application device for vehicles, in particular rail vehicles, comprising a unit for emergency release and a unit for auxiliary release. The release units are integrated into a combined device for emergency and auxiliary release of the brakes. The combined device is electrically actuated by a common drive unit.

Abstract: The invention provides an electromechanical actuator for a vehicle brake, the actuator comprising: a motor; a screw-and-nut system having a first element, the screw or the nut, rotated by the motor; and an antirotation member preventing rotation of the second element of the screw-and-nut system, the nut or the screw, so that the second element moves linearly in response rotation of the motor so as to exert compression selectively on friction elements of the brake. According to the invention, the actuator is subdivided into a first portion comprising the screw-and-nut system, and a second portion comprising the motor, the portions being designed to be separable while the actuator is mounted on a brake.

Abstract: A parking brake assembly for an air actuated disc brake includes an operating shaft for amplifying a force supplied by an air actuator and transmitting the force to brake pads. The operating shaft is pivotable about an axis between a rest position at which a braking force is not applied and an actuated position at which the braking force is applied. An abutment surface on the operating shaft is selectively engageable by a complementary latch of the assembly to retain the operating shaft in the actuated position and thereby apply the parking brake. The abutment surface has a helical configuration.

Abstract: A disc brake for a commercial vehicle, operated pneumatically or by electric motor, comprising a brake caliper, an application device and at least one adjuster device arranged with the brake caliper, is characterized in that both adjuster elements of the at least one adjuster device are fixed in a non-rotating manner to a common connector plate in the region thereof facing the brake lining and/or a single- or multi-piece thermal insulation layer is at least partly applied to the connector plate or parts connected thereto on the side thereof facing the relevant braking lining to form a region like a pressure piece.

Abstract: The actuator comprises a tubular nut (22) coupled by means of an external thread (21) to the casing (12) of the actuator. The nut has an internal thread (23) opposite the external thread, for engaging a threaded rod (11) which is prevented from rotating with respect to the casing. A geared motor (13, 14) rotates a pinion (15) which, through two straight spur gears (161, 162), causes the nut (22) to bring about a screwing movement along a longitudinal axis (x), while the rod (11) translates rapidly in telescopic manner with respect to the casing (12). The spur gears have a pinion portion of greater diameter (161a, 162a) meshing with the pinion (15), and a splined shaft portion (161b, 162b) meshing with a pinion member (22b) integral with the nut (22).

Abstract: A linear electromechanical actuator of the screw type for a parking brake including a tubular nut (22) coupled by means of an external thread to the casing (12) of the actuator and operated to perform a screwing movement about and along a longitudinal axis (x). The nut has an internal thread (23) opposite the external thread, for engaging a threaded rod (11) which is prevented from rotating with respect to the casing. Operation of the electrical motor (13) brings about a telescopic movement of the nut (22) and the rod (11) with respect to the casing (12), with a rapid linear translation of the rod (x).

Abstract: Axial grooves 8e and circumferential groove 8f intersecting with he axial grooves are provided in a cylinder bore 8e. A fixed-side cam plate 12 has anti-rotation projections 12c, which are projected from the fixed-side cam plate 12 and inserted into the axial grooves 8e, and fastening grooves 12d, which are formed at circumferential areas of the bottom side of the fixed-side cam plate 12 at a circumferential side of each of anti-rotation projections 12c. The housing 16 has engagement ribs 16e which are projected from the housing 16 to be engaged with the axial grooves 8e, and fastening pieces 12f, which are formed at a circumferential side of each of the engagement ribs 16e, the fastening pieces 12f being fitted in the fastening grooves 12d.

Abstract: An actuating unit for an electromechanically actuatable disk brake for motor vehicles consists essentially of a drive unit (1), i.e., an electric motor (11); an actuating element (7), by means of which one (4) of two friction linings (4, 5) mounted with limited freedom of movement in a brake caliper can be brought into engagement with a brake disk (6); and a first and a second reducing gear (2, 3). An electronic controller (8), which serves to drive the electric motor (11), is assigned to the actuating unit. To realize an actuating unit of compact axial dimensions which is also optimally designed with respect to packaging, at least part of the electronic controller (8) is mounted between the electric motor (11) and the housing (25) which holds the second reducing gear (3).

Abstract: A relay switch for selectively connecting a power supply line of an inverter to a ground line is inserted between the inverter and a power source, and a power consumption unit such as a resistor element is inserted between the relay switch and ground line.

Abstract: An actuating unit is provided for an electromechanically actuated disc brake for automotive vehicles, substantially comprising a driving unit or an electric motor, an actuating element by which one of two friction linings displaceably arranged within a brake caliper is brought into engagement with a brake disc, and a reduction gear. In order to determine a reaction force occurring during actuation, a sensor device for sensing the reaction force resulting from the actuating force applied by the actuating unit is provided between the guide piece and the brake caliper or a gearbox housing connected to the brake caliper, respectively.

Abstract: A parking and emergency brake device having an actuating device (10) that is supplied with pressurized fluid wherein a piston (14) slides in a cylinder (12, 22) to axially delimits a front hydraulic pressure chamber (16) and exert a determined mechanical force on an operating member over an actuating travel and a valve (18) to selectively place the front pressure chamber (16) in communication with a pressurized hydraulic fluid supply port (20). The valve (18) is interposed between the piston (14) and the cylinder (12) to controlled by an axial movement of the piston (14) over a control travel prior to actuating travel.

Abstract: A combined service and parking brake apparatus includes a piston which forms a hydraulic chamber within a cylinder portion; a brake lining which, when pressed by the piston, brakes rotation of a disc rotor; a second piston which divides the hydraulic changer into a first hydraulic chamber and a second hydraulic chamber; a friction clutch which allows rotation of the second piston when the second piston is held at its home position and which disables rotation of the second piston when the second piston moves by a predetermined distance toward the second hydraulic chamber; an adjuster including an internal-thread portion and an external-thread portion and adapted to adjust the clearance between the pistons in accordance with the amount of wear of the brake lining; and a changeover valve for establishing and shutting off the communication between the first hydraulic chamber and the second hydraulic chamber.

Abstract: By forging a metal material, there is formed a dustproof boot 20 in which a side of an opening end portion 20b formed with a groove 34 for a dustproof boot is provided with a diameter smaller than that of a side of a piston main body 20a, and a total thereof is provided with a substantially uniform wall thickness, thereafter, by carrying out ironing from a front end of the opening end portion 20b to the piston main body side, the recess groove 34 for the dustproof boot can be formed by providing a build-up portion 20c at the opening end portion.

Abstract: A relay switch for selectively connecting a power supply line of an inverter to a ground line is inserted between the inverter and a power source, and a power consumption unit such as a resistor element is inserted between the relay switch and ground line.

Abstract: The present invention concerns a disc brake having a fixed brake disc. On each of the opposing sides of the brake disc at least one brake pad is arranged. Furthermore, the disc brake has an actuator and a clamping device. The clamping device is axially fixed in relation to the brake disc, in order to facilitate that the brake pads are given a symmetrical movement in relation to the brake disc.

Abstract: A disc brake assembly has a hub that is rotatable about an axis and at least a pair of discs supported on the hub for relative axial movement along the axis of the hub with the discs having opposite sides presenting braking surfaces. A non-rotatable support structure supports a plurality of friction elements for relative axial movement into and out of frictional braking engagement with the braking surfaces of the discs. An electric actuator is mounted on the support structure adjacent at least one of the friction elements and is operative when actuated to move the friction elements into frictional braking engagement with the braking surfaces of the discs.

Abstract: In a brake apparatus, a lead in a meshed portion between an external-thread portion (second stationary screw element) of a threaded shaft and an internal-thread portion (second movable screw element) of a nut is shorter than that in a meshed portion between an internal-thread portion (first stationary screw element) of a cylinder and an external-thread portion (first movable screw element) of a second piston. Accordingly, as the second piston and the nut move toward a control chamber while rotating in a unitary condition via a friction clutch, the second piston and the nut are united via the friction clutch, so that a contact portion between the thread surface of the second stationary screw element and the thread surface of the second movable screw element and a contact portion between the thread surface of the first stationary screw element and the thread surface of the first movable screw element push out against each other.

Abstract: An electrically driven vehicle brake comprises a brake piston, which acts on at least one friction lining and can be displaced out of an initial position into an actuation position, in which the brake piston abuts the friction lining against a rotating member of the vehicle brake which is to be connected, fixed against rotation, to a wheel of the motor vehicle, and a transmission unit, driven by an electric motor and acting on the brake piston to actuate the brake piston, wherein the electric motor is to be triggered by an electronic control unit, which is also set up to detect performance parameters of the vehicle, the electric motor and/or the vehicle brake.