Computing device and method for determining a force acting on at least one transmission of an electric brake pressure increasing device of a vehicle from the outside

Abstract

The present vehicle relates to a computing device and a method for determining a force (F gear ) acting from the outside on at least one transmission (10) of an electric brake pressure increasing device of a vehicle, the method having the following steps: determining the force (F gear ) acting from the outside on at least one transmission (10) of an electric brake pressure increasing device at least in the case of taking into account at least one first sensor signal of at least one first sensor on a rotational angle of a rotor of an electric machine of the electric brake pressure increasing device from an initial position of the rotor and at least one second sensor signal of at least one second sensor on a piston adjustment travel (x2) of an adjustable piston (12) of the electric brake pressure increasing device connected to the rotor by means of the at least one transmission (10) from a piston initial position of the piston (12).

Description

Technical Field

[0001] This invention relates to a computing device for an electric brake pressure amplification device for a vehicle. It also relates to an electric brake pressure amplification device for a vehicle. Furthermore, it relates to a method for determining the force acting externally on at least one transmission device of the electric brake pressure amplification device for a vehicle. Background Technology

[0002] Electric brake pressure amplification devices are known from the prior art, such as the electromechanical brake force amplifier disclosed in DE 602 04 570 T2, which are equipped with a transmission device through which the adjustable piston of the corresponding electric brake pressure amplification device is connected to the motor of the same brake pressure amplification device. The brake pressure should be increased in at least one part of the braking system of the vehicle equipped with such an electric brake pressure amplification device. Summary of the Invention

[0003] The present invention provides a computing device for an electric braking pressure amplification device for a vehicle according to the present invention, an electric braking pressure amplification device for a vehicle according to the present invention, and a method according to the present invention for determining the force acting from the outside on at least one transmission device of the electric braking pressure amplification device for a vehicle.

[0004] This invention provides an advantageous possibility for determining the force acting externally on at least one transmission element of an electric brake pressure amplification device. In particular, the time profile of the force acting externally on at least one transmission element can be determined with significantly improved time resolution compared to the prior art using this invention. As will become clear from the following description, the force acting externally on at least one transmission element can be determined using a measurement frequency above 1000 Hz while maintaining reliable measurement accuracy. In contrast, pressure measurements performed using pressure sensors installed in the vehicle's own braking system are conventionally limited to a maximum measurement frequency of less than or equal to 100 Hz. Therefore, with this invention, the peak force of the force acting externally on at least one transmission element can also be detected, while the pressure peak (which frequently triggers the force peak) cannot be reliably measured using pressure sensors according to the prior art. Therefore, this invention enables a more reliable and accurate examination of the cause of the force peak triggering the force acting externally on at least one transmission element. This invention can therefore be used to extend the service life of an electric brake pressure amplification device by improving the protection of the transmission element of at least one electric brake pressure amplification device.

[0005] As will become clear from the following description, implementation / fulfillment of the present invention generally does not require an additional sensor system on a vehicle equipped with a corresponding electric brake pressure amplification device. Instead, implementation / fulfillment of the invention is possible by means of a simple design / programming of the electronic devices used for this purpose. Therefore, the use of the invention is not or almost not associated with additional costs.

[0006] In an advantageous embodiment of the computing device, the electronic device is designed and / or programmed such that the force acting externally on at least one drive of the electric brake pressure amplification device can be determined by means of the electronic device, taking into account at least one first sensor signal output by at least one motor current sensor. Because in many conventional electric brake pressure amplification devices, the motor is typically already equipped with its own motor current sensor, in the embodiment of the computing device described herein, it is not necessary to expand the sensor system to provide at least one first sensor signal.

[0007] Preferably, the electronic device is designed and / or programmed such that, with the aid of the electronic device, the adjustment stroke of the transmission component whose rotational motion by means of the rotor can be converted into at least linear motion from its initial position can be determined, taking into account at least one first sensor signal output by at least one motor current sensor, through which the motor force can be transmitted from the rotor to the adjustable piston via the transmission component. With the aid of the electronic device, together with taking into account the determined adjustment stroke of the transmission component, the force acting externally on at least one transmission component of the electric braking pressure amplification device can be determined. As will become clear from the following description, the process described herein can be performed with the aid of a relatively low-cost electronic device that requires relatively little structural space.

[0008] Advantageously, the electronic device is designed and / or programmed such that the force acting externally on at least one transmission device of the electric brake pressure amplification device can be determined electronically, taking into account at least one second sensor signal output by at least one rod-type stroke sensor. Electric brake pressure amplification devices equipped with their own rod-type stroke sensors are already relatively common in the prior art. Therefore, in the embodiment of the computing device described herein, it is not necessary to expand the sensor system of the corresponding electric brake pressure amplification device in order to provide at least one second sensor signal.

[0009] In a preferred embodiment, the electronic device is designed and / or programmed such that, by means of the electronic device, the piston adjustment stroke of the adjustable piston from its initial position can be read or determined, taking into account at least one second sensor signal output by at least one rod-type stroke sensor. If necessary, the force acting externally on at least one transmission device of the electric brake pressure amplification device can be determined by means of the electronic device, taking into account the read or determined piston adjustment stroke. The process described in this paragraph can also be performed using relatively low-cost electronic devices that require less structural space.

[0010] In particular, electronic devices can be designed and / or programmed to enable electronic devices to respond to F gear =c gear (x2-x1) Determine the force F acting externally on at least one transmission device of the electric braking pressure amplification device. gear Where x2 is the read or determined piston adjustment stroke of the adjustable piston, x1 is the determined adjustment stroke of the transmission component, and c gear It is a constant value stored in the storage unit of the computing device. Therefore, in order to determine the force F acting on at least one transmission device from the outside... gear The calculation steps to be performed are relatively simple.

[0011] alternative location, c gear It can also be achieved by using electronic devices to consider at least one provided sensor value and c, taking into account at least one physical parameter. gear The value determined in the case of a function stored in a storage unit in relation to at least one physical parameter. As at least one physical parameter, the temperature present in at least one portion of the volume of the electric braking pressure amplification device, for example, can be determined by c. gear The values ​​are considered together. Therefore, the effect of strong temperature fluctuations on the elasticity or rigidity of the transmission may not or almost will not affect the determination of the force F acting on at least one transmission from the outside. gear Error in time.

[0012] In another advantageous embodiment of the computing device, the electronic device is additionally designed and / or programmed such that, by means of the electronic device, it can identify whether the brake control element connected to the hydraulic system equipped with the electric brake pressure amplification device is stuck, based on the force acting from the outside on at least one transmission device of the electric brake pressure amplification device, and can output corresponding information if necessary. Therefore, the present invention can also be used to warn the driver of a vehicle in advance of the sticking of the vehicle's brake control element (such as, in particular, the vehicle's brake pedal).

[0013] The aforementioned advantages are also achieved in an electric brake pressure amplification device for vehicles, which includes a corresponding computing device, a motor and an adjustable piston connected to the rotor of the motor via at least one transmission device, at least one first sensor by means of which provides an electronic device with a signal regarding the rotation angle of the rotor from its initial position to the computing device, and at least one second sensor by means of which provides an electronic device with a signal regarding the piston adjustment stroke of the adjustable piston from its initial position. The electric brake pressure amplification device can, for example, be a pre-mounted or pre-positionable electromechanical brake force amplifier in the vehicle's master brake cylinder. However, the electric brake pressure amplification device can also be an electric piston cylinder device integrated / integrable into a hydraulic system (such as, in particular, an IPB, integrated power brake) or a BWA device (brake-by-wire actuator). The embodiments listed herein for electric brake pressure amplification devices are not to be construed as definitive.

[0014] Furthermore, the aforementioned advantages are provided by the method for calculating the force on at least one transmission device of the electric brake pressure amplification device acting externally on the vehicle. It is explicitly indicated that this method can be improved based on the above-described embodiments of the computing device and / or the electric brake pressure amplification device. Attached Figure Description

[0015] Further features and advantages of the invention will then be described with reference to the accompanying drawings. Wherein:

[0016] Figure 1 shows a schematic diagram of the transmission device of the vehicle's electric brake pressure amplification device and a flowchart illustrating an implementation method for determining the force acting externally on at least one transmission device; and

[0017] Figure 2 A schematic diagram illustrating an embodiment of a vehicle's computing device or an electric brake pressure amplification device interacting with it is shown. Detailed Implementation

[0018] Figure 1a and Figure 1b A schematic diagram of the transmission device for an electric brake pressure amplification device in a vehicle is shown, along with a flowchart illustrating an implementation method for determining the force acting from the outside on at least one transmission device.

[0019] It is explicitly stated that the feasibility of the further described method is not limited to a specific type of electric brake pressure amplification device, nor is it limited to vehicles / motor vehicles of a particular type / motor model equipped with an electric brake pressure amplification device. Furthermore, in Figure 1aThe transmission device 10 schematically shown can be understood as (almost) any transmission device or similar device capable of adjusting the adjustable piston 12 of the electric brake pressure amplification device (not shown) via a motor, such that the adjustable piston 12 is connected / can be connected to the rotor of the motor at least via the transmission device 10. The adjustable piston 12 may also be connected to the transmission device 10 via at least one mechanical component, such as a platform. This is merely an example. Figure 1a The transmission device 10 is the transmission device 10 of the electromechanical braking power amplifier, and the adjustable piston 12 of the electromechanical braking power amplifier can be referred to as the valve body or the booster.

[0020] The force F acting on at least one transmission device 10 from the outside can be determined by the method described herein. gear This can be understood as the force F acting externally on the device increasing the electric braking pressure. gear For example, especially pressure. In the method described herein, the force F acting externally on at least one transmission device 10 is determined, taking into account at least one first sensor signal and at least one second sensor signal. gear .

[0021] At least one first sensor signal can be understood as a signal output by at least one first sensor regarding the (current) rotation angle of the rotor of the motor of the electric brake pressure amplification device from its initial position. Specifically, the rotor may exist in its initial position during the motor's deactivated / unenergized mode. A force F is applied externally to at least one transmission device 10 of the electric brake pressure amplification device. gear For example, it can be determined together considering at least one first sensor signal output by at least one motor current sensor (as at least one first sensor). The current intensity of the supply current guided through at least one winding of the motor, read from at least one first sensor signal of at least one motor current sensor, typically causes a corresponding rotation angle of the rotor from its initial position. This can also be described as such that the rotation angle of the rotor from its initial position is typically a function of the current intensity of the motor's supply current. (This, however, is not a prerequisite in principle.) The current intensity of the motor's supply current can be measured with relatively high measurement accuracy / resolution, therefore, the rotation angle of the rotor from its initial position can also be determined relatively accurately. Furthermore, even low-cost motor current sensors can typically measure the current intensity of the supply current at a measurement frequency of at least 1000 Hz.

[0022] The (current) rotation angle of the rotor from its initial position typically corresponds to the (current) adjustment stroke x1 of the transmission component 14 of the transmission device 10. The transmission component can be converted / can be converted into linear motion by means of the rotor's rotational movement, and the motor force of the motor is transmitted / can be transmitted from the rotor to an adjustable piston 12 connected to the rotor via at least one transmission device 10. The adjustment stroke x1 of the transmission component 14 refers to the adjustment stroke x1 of the transmission component 14 from its initial position. In particular, the transmission component 14 can be in its initial position when the rotor is in its initial position.

[0023] Therefore, the embodiment of the method described herein has method step S1, in which the adjustment stroke x1 of the transmission component 14 of the transmission device 10 from its initial position is determined, taking into account at least one first sensor signal output by at least one motor current sensor. Because electric brake pressure amplification devices typically have their own motor current sensor for determining / measuring the current intensity of the supply current of the motor of the electric brake pressure amplification device, the feasibility of method step S1 in such electric brake pressure amplification devices does not require an additional sensor system. Due to the relatively high measurement accuracy / resolution of at least one motor current sensor, the adjustment stroke x1 of the transmission component 14 of the transmission device 10 from its initial position can typically be determined with a measurement accuracy / resolution of approximately 1 µm. Accordingly, the adjustment stroke x1 of the transmission component 14 of the transmission device 10 from its initial position can be continuously re-determined while reliably maintaining a "measurement frequency" of at least 1000 Hz.

[0024] At least one second sensor signal can be understood as a signal output by at least one second sensor regarding the (current) piston adjustment stroke x2 of the adjustable piston 12 connected to the rotor via at least one transmission device 10 from its initial piston position. The adjustable piston 12 may also be in its initial piston position at least with the rotor in its initial posture and without any external force acting on the transmission device 10. Advantageously, the force F acting externally on the at least one transmission device 10 can be determined by taking into account the at least one second sensor signal output by at least one rod-type stroke sensor (as at least one second sensor). gear In a conventional manner, electric brake pressure amplification devices typically have their own rod-type stroke sensor for determining / measuring the piston adjustment stroke x2 of the adjustable piston 12. Therefore, relatively little expansion of the sensor system of the corresponding electric brake pressure amplification device is required to determine / measuring the piston adjustment stroke x2 of the adjustable piston 12.

[0025] In the embodiments described herein, in method step S2, the piston adjustment stroke x2 of the adjustable piston 12 from its initial position is read or determined, taking into account at least one second sensor signal output by at least one lever-type stroke sensor. The piston adjustment stroke x2 of the piston 12 from its initial piston posture can typically be determined with a measurement accuracy / resolution of approximately 1 μm using at least one lever-type stroke sensor. Furthermore, even low-cost lever-type stroke sensors can have a measurement frequency of at least 1000 Hz. Method step S2 can be optionally performed before, after, simultaneously with, or concurrently with method step S1.

[0026] In method step S3, performed according to method steps S1 and S2 in the embodiment of the method described herein, a force F is applied externally to at least one transmission device 10 of the electric braking pressure amplification device. gear It is determined, at least taking into account the determined adjustment stroke x1 of the transmission component 14 and the output or determined piston adjustment stroke x2 of the adjustable piston 12. For example, the force F acting externally on at least one transmission component 10 of the electric brake pressure amplification device. gear It can be determined according to the following formula (Formula 1): (Formula 1) F gear = c gear (x2– x1)

[0027] Where c gear It is a constant value reflecting the bending stiffness of the transmission device 10 or a value determined according to at least one physical parameter. gear For example, it can be in the range of 5 kN / mm to 25 kN / mm.

[0028] Typically, the transmission device 10 of the electric braking pressure amplification equipment is relatively robust to changes in environmental parameters, such as temperature fluctuations. Therefore, for c gear A constant value stored in a memory cell (such as EEPROM) can typically be used. gear The constant value can be measured and stored specifically for the device after the electric braking pressure is increased in the factory.

[0029] Alternatively, c can also be stored on the storage unit. gearA function relating to at least one physical parameter, such as the temperature in at least one portion of the volume of an electric braking pressure amplification device. The method described herein may therefore also have (optionally) sub-steps S3a and S3b of method step S3. In sub-step S3a, at least one physical parameter may be measured. Subsequently, in sub-step S3b, c may be calculated using a stored function based on at least one measured sensor value for at least one physical parameter. gear The (current) value.

[0030] The method described herein has the advantage that all its steps S1 to S3 can be executed relatively quickly. Therefore, the force F acting externally on at least one transmission device 10 of the electric brake pressure amplification device... gear The frequency that can be continuously redefined using the methods described herein is (essentially) limited only by the achievable measurement frequencies of at least one motor current sensor and at least one rod-type stroke sensor. However, at least one motor current sensor and at least one rod-type stroke sensor can have measurement frequencies significantly higher than the highest achievable measurement frequency for pressure measurements performed using at least one pressure sensor. This is even though low-cost motor current sensors and rod-type stroke sensors typically have measurement frequencies of at least 1000 Hz (Hertz) during periods when pressure measurements are generally performed only at a maximum measurement frequency of less than or equal to 100 Hz (Hertz).

[0031] Therefore, the force F acting externally on at least one transmission device 10 of the electric brake pressure amplification device gear The force F can be readily determined at a frequency of at least 1000 Hz using the method described herein. This ensures the determination / tracking of the force F acting externally on at least one transmission device 10 of the electric braking pressure amplification device. gear The force curve over time has an advantageous high time resolution. Due to the aforementioned relatively high measurement accuracy / resolution of both low-cost motor current sensors and rod-type stroke sensors, the force F acting externally on at least one transmission device 10 of the electric braking pressure amplification device... gear It can be determined with additional precision using the methods described herein.

[0032] It is also indicated here that the influence of sensor noise and its correlation with external parameters, such as air humidity, are minimal, as is the force F acting externally on at least one transmission device 10 of the electric braking pressure amplification device. gear It can be determined with the desired high precision.

[0033] Force F gear The force value or force F is determined by the method described herein. gearThe force curve over time determined by the method described herein can be used to improve the function performed by at least one additional braking system component of a braking system equipped with an electric brake pressure amplification device and / or a braking system using an electric brake pressure amplification device. In this way, the service life of the electric brake pressure amplification device and / or at least one additional braking system component can be extended. For example, in (optional) method step S4, the force F acting from the outside on at least one transmission device 10 of the electric brake pressure amplification device can be used to... gear Check whether the brake control element connected to the hydraulic system equipped with the electric brake pressure amplification device is stuck. If necessary, i.e., if the brake control element is found to be stuck, then the corresponding information can be output.

[0034] Figure 2 A schematic diagram illustrating an embodiment of a vehicle's computing device or an electric brake pressure amplification device interacting with it is shown.

[0035] For example only, in Figure 2 In this embodiment, the electric brake pressure amplification device 20 is a front-mounted / potentially front-mounted electromechanical brake force amplifier in the vehicle's master brake cylinder 22. However, it is indicated that the availability of the computing device 24, further described, is not limited to this type of electric brake pressure amplification device 20. Accordingly, the availability of the computing device 24 is also not limited to vehicles / motor vehicles of a specific vehicle type / motor type equipped with a corresponding electric brake pressure amplification device. The fact that the master brake cylinder 22, located behind the electromechanical brake force amplifier, is constructed with a rod piston 22a and a floating piston 22b should not be interpreted as necessary.

[0036] Figure 2 The electric brake pressure amplification device 20 has an adjustable piston 12, which is connected to the rotor of the motor 26 via at least one transmission device 10. For example, the adjustable piston 12 is a valve body (assistive element). The transmission device 10 is configured with at least one transmission component 14, which is connected / can be connected to the rotor, such that the transmission component 14 is at least converted / can be converted into linear motion by means of the rotational motion of the rotor. This is merely an example. Figure 2 The transmission component 14 of the electric brake pressure amplification device 20 is a main shaft 14, with a main shaft nut 28 engaged with it, causing the main shaft nut 28 to rotate along with the rotor's rotational motion, thus converting the main shaft 14 into its linear motion. Furthermore, Figure 2 The electric brake pressure amplification device 20 is also optionally equipped with an output piston 30, a reaction disc 32, and an input rod 34.

[0037] The computing device 24 has at least one electronic device 24a, which can be integrated, in particular, into the control electronics of the electric brake pressure amplification device 20. Alternatively, the electronic device 24a can also be constructed separately from the control electronics of the electric brake pressure device 20.

[0038] Electronic device 24a is designed and / or programmed to determine / determine the force acting externally on at least one transmission device 10 of the electric brake pressure amplification device 20. The force acting externally on at least one transmission device 10 is determined by taking into account at least one first sensor signal (not shown) regarding the rotation angle of the rotor of motor 26 from its initial rotor posture and at least one second sensor signal (not shown) regarding the piston adjustment stroke of adjustable piston 12 from its initial piston position. Examples of at least one first sensor and at least one second sensor have been mentioned above.

[0039] The electronic device 24a may in particular be designed and / or programmed to perform at least one of the steps of the above-described process or method.

Claims

1. A computing device (24) for an electric brake pressure amplification device (20) for a vehicle, characterized in that... An electronic device (24a) is designed and / or programmed such that, by means of the electronic device (24a), at least considering at least one first sensor signal of at least one first sensor regarding the rotation angle of the rotor of the motor (26) of the electric braking force amplifying device (20) from the initial posture of the rotor, and at least one second sensor signal of at least one second sensor regarding the piston adjustment stroke (x2) of the adjustable piston (12) of the electric braking force amplifying device (20) connected to the rotor via at least one transmission device (10) from the initial piston position of the piston (12), the force (F) acting externally on the at least one transmission device (10) of the electric braking force amplifying device (20) can be determined. gear ).

2. The computing device (24) according to claim 1, wherein, The electronic device (24a) is designed and / or programmed such that the force (F) acting from the outside on at least one transmission device (10) of the electric brake pressure amplification device (20) gear The information can be determined by means of the electronic device (24a) taking into account the signal of the at least one first sensor output by at least one motor current sensor.

3. The computing device (24) according to claim 2, wherein, The electronic device (24a) is designed and / or programmed such that: with the aid of the electronic device (24a), taking into account the at least one first sensor signal output by the at least one motor current sensor, the adjustment stroke (x1) of the transmission component (14) of the transmission device (10), whose rotational motion by means of the rotor can be at least converted into linear motion, from the initial position of the transmission component (14), can be determined, and the motor force can be transmitted from the rotor to the adjustable piston (12) through the transmission component; and with the aid of the electronic device (24a), together taking into account the determined adjustment stroke (x1) of the transmission component (14), the force (F) acting externally on the at least one transmission component (10) of the electric brake pressure amplification device (20) can be determined. gear ).

4. The computing device (24) according to any one of the preceding claims, wherein, The electronic device (24a) is designed and / or programmed such that the force (F) acting from the outside on at least one transmission device (10) of the electric braking pressure amplification device (20) gear It can be determined by means of the electronic device (24a), taking into account the signal of the at least one second sensor output by at least one rod-type stroke sensor.

5. The computing device (24) according to claim 4, wherein, The electronic device (24a) is designed and / or programmed such that, with the aid of the electronic device (24a), the piston adjustment stroke (x2) of the adjustable piston (12) from its initial piston position can be read or determined from the at least one second sensor signal output by the at least one rod-type stroke sensor, and, with the aid of the electronic device (24a), the force (F) acting externally on the at least one transmission device (10) of the electric brake pressure amplification device (20) can be determined from the same consideration of the read or determined piston adjustment stroke (x2). gear ).

6. The computing device (24) according to claims 3 and 5, wherein, The electronic device (24a) is designed and / or programmed such that, by means of the electronic device (24a), according to F gear =c gear (x2-x1) can determine the force F acting from the outside on at least one transmission device (10) of the electric brake pressure amplification device (20). gear , Wherein, x2 is the read or determined piston adjustment stroke of the adjustable piston (12), x1 is the determined adjustment stroke of the transmission component (14), and c gear It is a constant value stored in the storage unit of the computing device (24a).

7. The computing device (24) according to claims 3 and 5, wherein, The electronic device (24a) is designed and / or programmed such that, by means of the electronic device (24a), according to F gear =c gear (x2-x1) can determine the force F acting from the outside on at least one transmission device (10) of the electric brake pressure amplification device (20). gear , Wherein, x2 is the read or determined piston adjustment stroke of the adjustable piston (12), x1 is the determined adjustment stroke of the transmission component (14), and c gear It is by means of the electronic device (24a) that at least one provided sensor value and c are considered in consideration of at least one physical parameter. gear The value determined in the case of a function stored on the storage unit in relation to the at least one physical parameter.

8. The computing device (24) according to any one of the preceding claims, wherein, The electronic device (24a) is additionally designed and / or programmed such that, by means of the electronic device (24a), the force (F) acting from the outside on at least one transmission device (10) of the electric braking pressure amplification device (20) is applied. gear It can identify whether the brake control element connected to the hydraulic system equipped with the electric brake pressure amplification device (20) is stuck, and can output the corresponding information when necessary.

9. An electric brake pressure amplification device (20) for a vehicle, comprising: The computing device (24) according to any one of the preceding claims; The motor (26) and the adjustable piston (12) connected to the rotor of the motor (26) via the at least one transmission device (10). The at least one first sensor, by means of which at least one first sensor signal relating to the rotation angle of the rotor from the initial posture of the rotor can be provided to the electronic device (24a) of the computing device (24); and At least one second sensor, by means of which the at least one second sensor signal is provided to the electronic device (24a) regarding the piston adjustment stroke (x2) of the adjustable piston (12) from the initial position of the piston.

10. The electric brake pressure increasing device (20) according to claim 9, wherein, The electric brake pressure amplification device (20) is an electromechanical brake force amplifier (20) that is located in front of or can be located in front of the main brake cylinder (22) of the vehicle.

11. A force (F) on at least one transmission device (10) of an electric braking pressure amplification device (20) acting externally on a vehicle. gear The method, characterized by the following steps: Taking into account at least one first sensor signal from at least one first sensor regarding the rotation angle of the rotor of the motor (26) of the electric braking force amplifying device (20) from the initial posture of the rotor, and at least one second sensor signal from at least one second sensor regarding the piston adjustment stroke (x2) of the adjustable piston (12) of the electric braking force amplifying device (20) connected to the rotor via the at least one transmission device (10) from the initial piston position of the piston (12), the force (F) acting externally on the at least one transmission device (10) of the electric braking force amplifying device (20) is determined (S3). gear ).

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