Electromechanical brake actuator (EMB) for a friction brake of a vehicle and method for operating such a brake actuator

Abstract

The present invention relates to an electromechanical brake actuator (EMB) (100) for a friction brake of a vehicle, wherein a force path (112) of the electromechanical brake actuator (100) runs from an electric drive (104) of the electromechanical brake actuator (100) via a mechanism (106) of the electromechanical brake actuator (100) to an interface (102) of the electromechanical brake actuator (100) to the friction brake, wherein a switchable blocking path (114) branches off from the force path (112) to a fixed point (116) on a housing of the electromechanical brake actuator (100), wherein the blocking path (114) runs from the force path (112) via a force accumulator (120) and a switchable clutch (118), wherein the drive (104) is designed to, via the force path (112) at the interface (102) to build up a braking force (122), wherein the energy accumulator (120) is designed to store at least a portion of the braking force (122),when the clutch (118) is closed and the drive (104) is deactivated.,

Description

Field of the InventionThe invention relates to an electromechanical brake actuator (EMB) for a friction brake of a vehicle, to a method for operating a corresponding electromechanical brake actuator (EMB), and to a corresponding computer program product.Prior ArtAn electromechanical brake actuator can provide a braking force to a friction brake via a drive and a mechanism. As long as the braking force is requested, the drive is energized. If the drive is switched to the zero current state, the braking force falls or the braking force ceases.Therefore, an electromechanical brake actuator can have a force accumulator for a parking brake. The energy store may be, for example, a prestressed spring which is released when the vehicle is parked. As a result, a vehicle can be protected from rolling away even when the brake actuator is not powered. The energy store can be prestressed again by a reverse operation of the electromechanical brake actuator when the parking brake is released.DE 198 59 325 A1 describes an electromechanical wheel brake device which presses a friction brake lining against a brake body by means of an electric motor via a spindle drive, wherein a spindle of the spindle drive is held in a rotationally fixed manner by means of a releasable brake.Disclosure of the InventionAgainst this background, the approach presented here presents an electromechanical brake actuator (EMB) for a friction brake in a vehicle, a method for operating a corresponding electromechanical brake actuator (EMB), and a corresponding computer program product according to the independent claims. Advantageous refinements and improvements of the approach presented here are evident from the description and are described in the dependent claims.Advantages of the InventionA force path of an electromechanical brake actuator and a connected friction brake may have a high stiffness. As a result, a braking force at the friction brake can be set very directly. Due to the high rigidity, the friction brake and a mechanism arranged in the force path are elastically deformed only slightly by the braking force.The components of the mechanism and of the friction brake, like all materials, have a more or less pronounced thermal expansion. Heating during a braking process or over a plurality of braking processes can be compensated simply by tracking an operating point of the drive and of the mechanics, since a drive continuously provides a driving force or a driving torque for providing the braking force.If the friction brake is blocked after the braking process in its position reached during the braking process, a thermal shrinkage during cooling has a strong effect on a remaining braking force due to the high rigidity. As a result of the cooling, the remaining braking force falls.In the approach presented here, the braking force when the friction brake is locked is reduced in a controlled manner by storing a portion of a mechanical stress in the force path caused by the braking force in an elastic force accumulator. The energy store reduces overall rigidity of the system and changes in length due to the thermal shrinkage have less effect on the remaining braking force.The approach presented here makes it possible to block a rigid brake for use as a parking brake without any remaining braking force being reduced in an uncontrolled manner when the brake cools down.According to a first aspect of the invention, an electromechanical brake actuator (EMB) for a friction brake in a vehicle is presented, wherein a force path of the EMB runs from an electric drive of the EMB via a mechanism of the EMB to an interface of the EMB with the friction brake, wherein a switchable locking path branches off from the force path to a fixed point on a housing of the EMB, wherein the locking path runs from the force path via a force accumulator and a switchable clutch, wherein the drive is configured to build up a braking force via the force path at the interface, wherein the force accumulator is configured to store at least a portion of the braking force when the clutch is closed and the drive is deactivated.According to a second aspect of the invention, a method for operating an electromechanical brake actuator according to the first aspect is presented, wherein a braking force is built up at the interface via the force path in order to activate a parking brake function of the EMB using the drive, the clutch is closed in the locking path and the drive is deactivated, wherein at least a portion of the braking force is stored as a counterforce in the energy store.Ideas regarding embodiments of the present invention can be considered, among other things, to be based on the ideas and findings described below.An electromechanical brake actuator may be referred to as an EMB for short. The EMB can have an electric motor as drive and a gear as mechanics. The EMB may act on a disc brake or a drum brake. The disc brake and the drum brake are friction brakes. An interface to the friction brake may be arranged at an output of the transmission.The gear can be, for example, a rotational-translatory gear, i.e. convert a rotational movement of the drive into a linear movement. The rotational-translatory gear can be, for example, a spindle drive. A torque of the drive can be amplified by a transmission connected upstream.A force path depicts a force flow through the mechanism. The force path may be a virtual line. The force path connects in sequence all members of the mechanics that participate in the force flow through the mechanics. The force path can be nested, for example, by stages of the transmission. Members of the mechanism that are moved without force are not part of the force path, but can be part of at least one other path.A blocking path can likewise be a force path and can be formed by members of the mechanism. The blocking path can have a switchable clutch as the blocking element. In contrast to the actual force path, a force flow through the blocking path only occurs when the blocking path is closed, i.e. continuous. The blocking path is connected at one end to a member of the force path. At the other end, the blocking path is rigidly connected to a fixed element. Members of the blocking path between the member of the force path and the clutch are moved without force by the mechanism as long as the clutch is open. Only when the clutch is closed does a force act on the members of the locking path.A force storage device can be elastically deformed by an applied force. The deformation can be completely reversed, i.e. not plastic. The energy store has a defined spring constant. A magnitude of the force acting on the force accumulator determines an elastic deformation of the force accumulator.The locking path may branch off at any member of the force path. In this case, a torque to be blocked via the blocking path is the greater the farther the blocking path branches off from the drive.The mechanism can be moved in a forward direction by the drive when the braking force is built up. The mechanism can be moved in a rearward direction when storing the portion of the braking force counter to the forward direction until the counter force corresponds to the remaining braking force. During braking, the mechanism can be braced, since the members of the mechanism are each slightly elastically deformed by the braking force. When storing the portion of the braking force, the members of the mechanism can then be partially relaxed, i.e. partially deformed back. The rearward relaxation of the members of the force path leads to a tensioning of at least the force accumulator in the blocking path.To release the parking brake function, braking force can be built up again by the drive via the force path and the counterforce in the force accumulator can be reduced. The clutch can be opened when the counterforce is approximately reduced. The built-up braking force can be reduced by the drive in a controlled manner via the force path after the clutch has been opened. For releasing, the force path can be tensioned again in the forward direction. As a result, the clamping of the energy store is reduced and the clutch can be opened approximately without force. Subsequently, the drive can reduce the braking force in a controlled manner in order to release the friction brake.The energy store can be an elastic spring. The spring may be tensioned when the clutch is closed and the drive is deactivated. Alternatively or additionally, the energy store can comprise an elastomer. A spring can in particular consist of a metal material.The mechanism can comprise a rolling gear. The blocking path can branch off at a gearwheel of the rolling gearing, The energy store can be a torsion spring. A rolling gear can have at least one stage made of at least two gearwheels. The blocking path may be connected to one of the gears. The lock-up path to the clutch is free to rotate until the clutch is closed. When the clutch is closed, the locking path and in particular the energy accumulator is twisted or elastically deformed.The energy store can be prestressed. The energy store can have a stop which prevents relaxation beyond a specific point. The prestress allows the energy store to be deformed only when the blocking force is greater than the prestress. As a result of the prestress, an increased voltage in the force path can be maintained.The energy store can be arranged between the mechanism and the coupling. The energy store can move without force with the mechanism when the clutch is open. Only when the clutch is closed can one end of the energy accumulator be fixed and the other end moved relative thereto in order to build up the blocking force.Alternatively or additionally, the energy store can be arranged between the coupling and the fixed point. The energy store can be immovable when the clutch is open. Only when the clutch is closed can the ends of the force accumulator be moved relative to one another in order to store the blocking force.The method described further herein is preferably computer-implemented and can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example, in a driver assistance system.The approach presented here furthermore creates a control device, wherein the control device is designed to carry out, actuate or implement the steps of a variant of the method presented here in corresponding devices.The control device can be an electrical device having at least one arithmetic unit for processing signals or data, at least one memory unit for storing signals or data, and at least one interface and / or one communication interface for reading in or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a so-called system ASIC or a microcontroller for processing sensor signals and outputting data signals depending on the sensor signals. The memory unit may be, for example, a flash memory, an EPROM, or a magnetic memory unit. The interface can be designed as a sensor interface for reading in the sensor signals from a sensor and / or as an actuator interface for outputting the data signals and / or control signals to an actuator. The communication interface can be designed to read in or output the data wirelessly and / or in a wired manner. The interfaces can also be software modules which are present, for example, on a microcontroller, in addition to other software modules.A computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used for carrying out, implementing and / or controlling the steps of the method according to one of the embodiments described above is also advantageous, in particular if the program product or program is executed on a computer, in a control device or a device.It is to be understood that some of the possible features and advantages of the invention are described herein with reference to various embodiments. One skilled in the art will recognize that the features may be combined, adjusted, or interchanged as appropriate to arrive at other embodiments of the invention.BRIEF DESCRIPTION OF THE DRAWINGEmbodiments of the invention are described below with reference to the attached drawing, wherein neither the drawing nor the description should be interpreted as restricting the invention. FIG. 1 shows an illustration of an electromechanical brake actuator according to an exemplary embodiment.The figure is schematic only and not to scale. Identical reference numerals designate identical or identically acting features.Embodiments of the InventionFIG. 1 shows an illustration of an electromechanical brake actuator 100 according to an exemplary embodiment. The electromechanical brake actuator 100 is referred to for short as EMB 100. The EMB 100 acts via an interface 102 on a friction brake, not shown, of a vehicle. The friction brake can be a disk brake or a drum brake. The EMB 100 has an electric drive 104 and a mechanism 106. The drive 104 is here a rotary electric motor. The mechanism 106 comprises a reducing roller gear 108 and a rotation / translation gear 110. The rolling gear 108 here has, for example, a gear stage, but can also be multi-stage. The rotation / translation gear 110 is, for example, a spindle drive or ball screw drive.When the drive 104 drives the mechanism 106, a force path 112 is formed from the drive 104 through the mechanism 106 to the interface 102. A torque of the drive 104 is transmitted along the force path 112 or increased by a transmission ratio of the mechanism 106.A blocking path 114 branches off from the force path 112 between the interface 102 and the drive 104. The blocking path 114 is likewise part of the mechanism 106 and has a switchable coupling 118 and a spring-elastic energy store 120 between a branching point from the force path 112 and a fixed point 116 on a housing of the mechanism 106.Here, the energy accumulator 120 is arranged between the branch point and the clutch 118. The energy store 120 is thus moved without the action of force by the drive 106 as long as the clutch 118 is open. Only when the clutch 118 is closed can a force act on the energy accumulator 120, which force is stored in the energy accumulator 120 by elastic deformation of the energy accumulator 120.In the approach presented here, during a braking process, the mechanism 106 is moved by the drive 104 until a desired braking force 122 is provided at the interface 102 via the force path 112. In this case, the force accumulator 120 is moved along without the action of a force. The mechanism 106 in the force path 112 is elastically braced by the required torque or the braking force 122 itself. The friction brake is also elastically braced by the braking force.When the vehicle is stationary, the braking force 122 is maintained by the actuator 104 until a parking brake function is activated and the clutch 118 is closed. The drive 104 is then deactivated or the torque is reduced in a controlled manner. In this case, the mechanism 106 is partially relaxed and at the same time the energy store 120 is elastically braced. The mechanism 106 can only expand until a counterforce stored in the force accumulator 120 balances a remaining clamping of the mechanism 106 and the friction brake.In one exemplary embodiment, the energy store 120 is a torsion spring or a torsion rod. The energy store 120 is coupled to a gearwheel of the rolling gearing 108. The clutch 118 has a locking actuator 124 with a locking pawl mounted on the fixed point 116 and a rotatably mounted locking element 126 on the energy accumulator 120. When the clutch 118 is open, the detent 126 rotates synchronously with the gear of the rolling gear 108. When the clutch is closed, the pawl rigidly connects the detent element to the fixed point 116. When the gearwheel rotates when the clutch 118 is closed, the energy store 120 is elastically twisted or braced.When the clutch 118 is closed and the drive 104 is deactivated, the gearwheel rotates backwards until a tension of the energy store 120 corresponds to a remaining tension of the friction brake and the mechanism 106.Possible embodiments of the invention are summarized again below or presented with a slightly different word selection.An EMB with a rigidity-optimized parking brake component is presented.Electromechanical brakes (EMB) may be used as a service brake. In this case, a clamping force is provided individually for each wheel by means of an electromechanical actuator. The electromechanical actuator-generally a BLDC motor-acts on a rotation-translation transmission. By way of the translation, for example, a piston is displaced in the direction of the brake disk, as a result of which a clamping force is built up.In automatic / electronic parking brakes (APB, EPB), a clamping force is provided or released again individually for each wheel-generally only at the rear axle-by means of an electromechanical actuator. The electromechanical actuator-generally an EC motor-acts on a rotation-translation gear. By way of the translation, for example, a piston is displaced in the direction of the brake disk, as a result of which a clamping force is built up.The service brake is generally designed to be rather rigid. This has the advantage that in hydraulic systems less brake fluid has to be displaced from the master brake cylinder in the direction of the wheels. In the case of EMBs, both controllability and the energy requirement for a braking process are more favorable if the system is as stiff as possible.When locking the parking brake, a defined clamping force is locked in. If, in the further course, the brake system (in particular linings and disks) cools down, this leads to a significant loss of clamping force due to changes in length. In order that the loss of clamping force is as low as possible, brake systems which are as soft as possible are advantageous from the standpoint of the parking brake.That is to say, the service brake should be designed as stiff as possible, and the parking brake should be designed as soft as possible. At the same time, however, both functions should be accommodated in a manner which is as advantageous as possible in terms of installation space.With the concept proposed here, both functions--hard service brake and soft parking brake--are taken into account. The effects on the installation space are minimal.Motor vehicles (passenger cars) must not only be accelerated, but also decelerated. The deceleration can be effected at least partially via the drive train. In this case, the kinetic energy of the vehicle can be converted into electrical energy and fed into the vehicle battery.In order to enable high decelerations or wheel-specific decelerations, disc brakes are used, among other things. The disk rotates with the respective wheels during travel in a rotationally fixed manner. The disc is surrounded by a brake caliper provided with friction linings. The friction linings are pressed against the brake disk during braking. The vehicle decelerates by converting the motive energy into frictional heat.The higher the clamping force generated by the actuator, the higher the braking torque. The deformation of the brake caliper during the braking operation is also dependent on the clamping force provided. In a comparatively rigid caliper, the deformation will be less than in a caliper with less stiffness.The aim is firstly to design the service brake as stiff as possible, since, on the one hand, controllability is simpler than in the case of a soft system and, on the other hand, because the clamping energy (spring energy) is lower. That is, the necessary energy to be provided for a defined clamping force is lower in rigid systems, as shown in the following table.Rigidity Rigidityhard / rigidsoft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft softExample Values for Spring Constant cTarget clamping force FF=20 kNClamping travel s=F / cs 1 = F / c 1 s 1 = 0,67 mms 2 = F / c 2 s 1 = 1,00 mmClamping energyFrom the perspective of the parking brake, it is advantageous if the system is rather soft. After shutdown, the brake system cools down. In most cases, the clamping force is sufficient to hold the vehicle permanently (sufficient clamping force reserve). However, the brakes are very hot from time to time. This is not only the case after very sporting driving, but can also occur during congested driving (frequent acceleration and deceleration) and longer driving on false legs. As a result of the heat input, the components (in particular brake disc and brake pads) expand.Within the scope of service braking, this change in length is unproblematic; only the working point of the actuator shifts accordingly. From the perspective of the parking brake, however, this leads to loss of clamping force during cooling. With the same caliper values as above, this means.Rigidity Rigidityhard / rigidsoft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft soft softExample Values for Spring Constant cTarget clamping force FF=20 kNChange in length by thermal relaxation (rather worst case value)s 3 = 0,200 mmF 1 = s 3 · c 1 F 1 = 6 kNF 1 = s 3 · c 2 F 1 = 4 kNIn the approach presented here, the service brake system is designed to be rather rigid and the parking brake system is designed to be rather soft. This is achieved by making the entire actuator train from the motor, via the reduction and rotation-translation gearing (service brake functional train), up to the brake caliper itself correspondingly robust and rigid. In the parking brake function, an elasticity (spring / torsion spring) is introduced between the locking and the service brake function train. This results in an overall spring constant which results from the series connection of the service brake functional train including brake caliper and the "connectable" spring element. Switching on can be made because this spring element becomes functionally active exclusively after activation of the parking brake.In other words, a concept of an electromechanical service brake (EMB) is presented, in which two different stiffnesses are used depending on the operation (parking / service brake).A spring constant of the service brake may be greater than a spring constant of the parking brake.The operating and parking brakes may be accommodated in one unit and may share essential components in the power flow.A spring-loaded element can be connected for the parking brake.The switching on / off can be effected by means of a linear motor with bistable behavior.The switching on / off can be effected by means of an actuating drive with a rotation-translation transmission.The parking brake can be overpressed by active operation of the service brake. In this case, the parking brake actuator changes from an active position into an inactive position without the latter being actively energized.A torsion spring or a spiral spring can be operatively inserted between the locking element and the reduction gear of the service brake. The torsion spring or spiral spring can alternatively or additionally be activated between a housing and the locking element for the parking brake.The activatable spring element of the parking brake can be prestressed. The spring element can be a captive spring. The captive spring ensures that the locking element does not oscillate when the service brake is inverted rapidly. The captive spring furthermore ensures that the spring is active with a defined minimum force after activation of the parking brake has taken place.When the service brake is active, a clamping force is built up on the brake caliper via the motor (actuator of the service brake) and the subsequent reduction gear via a rotation-translation gear. For the build-up of clamping force or a reduction of clamping force, only the motor is inverted in its control direction. The locking actuator is inactive, i.e. it does not form a positive or frictional connection with the locking element. The torsion spring or the torsion rod is in the idle state, but can also be loaded with a prestress. The locking element rotates 1:1 with the corresponding part of the reduction gear. The locking element can be placed with any desired reduction stage, for example also directly in the extension of the motor shaft. Only the spring-based coupling between the locking element and the reduction gearing or rotation-translation gearing is important here. Alternatively, the locking actuator can be spring-mounted at a fixed point. Then, the locking element can be rigidly coupled to the reduction gear or the rotation-translation gear.If the service brake is inactive, a sufficient holding force has previously been actively provided via the service brake. After the desired clamping force has been reached, the locking actuator is activated in such a way that it forms a force fit or form fit with the locking element. The locking actuator is embodied to be bi-stable, for example. That is, it can be held permanently in the inactive or active position without further energy having to be supplied. Only the change from active to inactive or back takes place with energy supplied from the outside. After successful activation of the locking, the engine torque is reduced. The rotational-translation gear now acts upon the clamping force into the gear and attempts to drive the reduction gear such that the clamping force is reduced overall. Since the locking mechanism is now active, a moment is built up to the same extent via the torsion element. The torsion element is softer than the torque train via the motor and the reduction gearing and rotation-translation gearing. When changing from the service brake to the parking brake (activation of the locking element), some clamping force is lost, but the torsion element is correspondingly further tensioned. The total energy remains in the system. If changes in length now occur during the parking process as a result of thermal relaxation (brake pads and brake disc become thinner), this can be at least partially compensated for by the torsion element. If the locking actuator were effective directly on the reduction gear (without torsion element), then the loss of clamping force directly corresponds to the spring constant of the brake caliper.If, on the other hand, the locking actuator is effective via a spring element (torsion element), as indicated, then the loss of clamping force corresponds to the combination of springs (series connection of brake caliper and torsion element), which is significantly lower.In the case of a brake which is not actuated, an air gap is established between the brake linings and the brake disc. This ensures that the residual braking torque is minimized during travel. When the brake is actuated, the impressed braking force is introduced and supported via the piston, the brake linings (including lining back plates and brake disk) into the brake caliper. The brake caliper deforms in accordance with the force level and the caliper stiffness. That is, due to the deformation of the brake caliper, spring energy is stored in the brake caliper.Finally, it should be noted that terms such as "having", "comprising", etc. do not exclude other elements or steps and terms such as "a" or "an" do not exclude a plurality. Reference signs in the claims should not be regarded as limiting.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 198 59 325 A1

[0004]

Claims

Electromechanical brake actuator (EMB) (100) for a friction brake of a vehicle, wherein a force path (112) of the electromechanical brake actuator (100) runs from an electric drive (104) of the electromechanical brake actuator (100) via a mechanism (106) of the electromechanical brake actuator (100) to an interface (102) of the electromechanical brake actuator (100) to the friction brake, wherein a switchable blocking path (114) branches off from the force path (112) to a fixed point (116) on a housing of the electromechanical brake actuator (100), wherein the blocking path (114) runs from the force path (112) via a force accumulator (120) and a switchable clutch (118), wherein the drive (104) is designed to, A braking force (122) is built up at the interface (102) via the force path (112), wherein the energy store (120) is designed to store at least a portion of the braking force (122) when the clutch (118) is closed and the drive (104) is deactivated.Electromechanical brake actuator (100) according to Claim 1, in which the energy store (120) is an elastic spring, the spring being tensioned when the clutch (118) is closed and the drive (104) is deactivated.Electromechanical brake actuator (100) according to one of the preceding claims, in which the mechanism (106) comprises a rolling gear mechanism (108) and the blocking path (112) branches off at a gearwheel of the rolling gear mechanism (108), wherein the energy store (120) is a torsion spring.Electromechanical brake actuator (100) according to one of the preceding claims, in which the energy store (120) is prestressed.Electromechanical brake actuator (100) according to one of the preceding claims, in which the energy store (120) is arranged between the mechanism (106) and the clutch (118).Electromechanical brake actuator (100) according to one of Claims 1 to 4, in which the energy store (120) is arranged between the clutch (118) and the fixed point (116).Method for operating an electromechanical brake actuator (100) according to one of Claims 1 to 6, wherein, in order to activate a parking brake function of the electromechanical brake actuator (100), a braking force (122) is built up at the interface (102) via the force path (112) using the drive (104), the clutch (118) is closed in the blocking path (114) and the drive (104) is deactivated, wherein at least a portion of the braking force (122) is stored as a counterforce in the force store (120).Method according to Claim 7, in which the mechanism (106) is moved in a forward direction by the drive (104) when the braking force (122) is built up, wherein the mechanism (106) is moved in a rearward direction in the storage of the portion of the braking force (122) counter to the forward direction until the counterforce corresponds to the remaining braking force (122).Method according to one of Claims 7 to 8, in which, in order to release the parking brake function, braking force (122) is built up again by the drive (104) via the force path (112) and the counterforce in the energy store (120) is reduced, the clutch (118) being opened when the counterforce is approximately reduced, the braking force (122) which has been built up being reduced by the drive (104) in a controlled manner via the force path (112) after the clutch (118) has been opened.Control device which is designed to carry out, actuate or implement the method according to one of Claims 7 to 9 in corresponding devicesA computer program product configured to direct a processor, when executing the computer program product, to execute, implement and / or drive the method according to any one of claims 7 to 9.A machine readable storage medium having stored thereon the computer program product of claim 11.

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