Control device and method for activating an electric brake booster of a vehicle brake system

Abstract

The invention relates to a control device (14) for an electric brake booster (10) of a vehicle brake system and to a method for activating an electric brake booster (10) of a vehicle brake system by ascertaining whether a motor force transmission element (20) is in its second initial position when an electric motor (16) is in its inactive mode, the motor force transmission element can be adjusted not only by operation of the motor (16), but also by a driver braking force transmission element (18) which is adjusted from a first initial position thereof by at least a predetermined threshold travel ([Delta] smax), the motor (16) being transferred into an initial operation during which a rotor of the motor (6) is rotated and operated if necessary, and the driver braking force transmission element (18) being adjusted from a second initial position of the motor (16) by at least a predetermined threshold travel ([Delta] smax). And determining at least once by means of at least one motor control signal (16s) of at least one motor sensor (16a) of the electric machine (16) whether a motor torque of the electric machine (16) exceeds a predetermined limit motor torque and / or whether a gradient of the motor torque exceeds a predetermined limit gradient, and wherein the gradient of the motor torque exceeds a predetermined limit gradient, the initial operation ends if the motor torque of the motor (16) exceeds a limit motor torque and / or the gradient of the motor torque exceeds a limit gradient.

Description

Technical Field

[0001] The invention relates to a control device for an electric brake booster of a vehicle brake system and an electric brake booster for a vehicle brake system, which is connected or can be connected upstream of a master brake cylinder of the vehicle brake system. In addition, the invention relates to a method for activating an electric brake booster of a vehicle brake system. Background Art

[0002] From the prior art, for example DE 10 2020 209 754 A1, an electric brake booster is known, which is connected or can be connected upstream of a master brake cylinder of a vehicle brake system. This electric brake booster has a driver brake force transmission element, by which the driver brake force applied to the brake actuating element can be transmitted to at least one adjustable piston of the master brake cylinder. In addition, this electric brake booster includes an electric motor and a motor force transmission element, which can be adjusted not only by the operation of the electric motor, but also by the driver brake force transmission element that is adjusted by at least one predefined threshold stroke, so that the driver brake force transmitted to the at least one adjustable piston of the master brake cylinder can be amplified by the motor force of the electric motor. Summary of the invention

[0003] The present invention provides a control device for an electric brake booster for a vehicle brake system having the features of claim 1, an electric brake booster for a vehicle brake system having the features of claim 6 (which is pre-connected or can be pre-connected to a master brake cylinder of the vehicle brake system), and a method for activating an electric brake booster for a vehicle brake system having the features of claim 7.

[0004] Advantages of the present invention

[0005] The present invention provides an advantageous possibility for activating an electric brake booster of a vehicle brake system in situations in which the driver of a vehicle equipped with the vehicle brake system has already actuated a brake actuating element / brake pedal of the vehicle before activating / starting the motor of the brake booster. To this end, the present invention provides an actuation of the motor which, in these situations, enables an early and reliable "catch-up" of the motor force transmission element of the brake booster by initial operation of the motor by means of the actuation. As will become apparent from the following description, the "catch-up" of the motor force transmission element, which has already been adjusted from its powerless initial position at the time of activating / starting the motor, can also be used additionally for initializing a travel sensor, by means of which current position information about the motor force transmission element, the driver's brake force transmission element of the brake booster and / or other force transmission elements downstream of the motor force transmission element and the driver's brake force transmission element can be determined respectively. The present invention can therefore also be used to reduce the requirements on the sensor system of the brake booster used. The present invention thus makes it possible to equip a plurality of brake booster types with a sensor system that is inexpensive and requires little structural space.

[0006] In a preferred embodiment of the control device, the electronic device is additionally designed and / or programmed to estimate or read from at least one motor sensor signal the cumulative rotation angle of the rotor from its rotor initial position to the position of the rotor at an identification time point (at which identification time point it can be identified by means of the electronic device that the motor torque of the motor exceeds the limit motor torque and / or the gradient of the motor torque exceeds a preset limit gradient) during initial operation based on the control of the motor by means of the electronic device, and to determine, taking into account at least the cumulative rotation angle, a first position description of a first position of the driver brake force transmission element at the identification time point and / or of a first adjustment stroke of the driver brake force transmission element adjusted from its first initial position at the identification time point, a second position description of a second position of the motor force transmission element at the identification time point and / or of a second adjustment stroke of the motor force transmission element adjusted from its second initial position at the identification time point, and / or a third position description of a third position of a further force transmission element arranged downstream of the driver brake force transmission element and the motor force transmission element at the identification time point and / or of a third adjustment stroke of the further force transmission element adjusted from its third initial position at the identification time point. The specific embodiment of the control device described here is therefore advantageously suitable for initializing the travel sensor.

[0007] In particular, the electronic device can be designed and / or programmed to determine the first position specification, the second position specification and / or the third position specification while taking into account the accumulated rotation angle and additionally taking into account at least one travel sensor signal of at least one travel sensor associated with the driver brake force transmission element, the motor force transmission element and / or the further force transmission element. As is clear from the following description, the additional joint consideration of at least one travel sensor signal allows a more precise determination of the first position specification, the second position specification and / or the third position specification. This advantage is ensured even when at least one travel sensor signal is measured by means of at least one travel sensor, which respectively outputs a travel sensor signal that changes periodically as a function of a first adjustment travel of the driver brake force transmission element from its first initial position, a second adjustment travel of the motor force transmission element from its second initial position and / or a third adjustment travel of the further force transmission element from its third initial position. Therefore, the embodiment of the control device described here can also interact with travel sensor types that can be manufactured inexpensively and can be easily installed.

[0008] In a further advantageous embodiment of the control device, the electronic device is designed and / or programmed to determine an initial travel difference between a first adjustment travel of the driver's brake force transmission element from its first initial position and a second adjustment travel of the motor force transmission element from its second initial position by means of the first position specification and the second position specification. Thus, a brake booster interacting by means of the embodiment of the control device described here does not require a travel difference sensor, which can only be installed with great effort because it is used as a sensor of the movement of the cable that needs to be moved.

[0009] Preferably, the electronic device is further designed and / or programmed to operate the electric motor in a travel difference control mode after the initial operation is completed, during which the electric motor force transmission element can be adjusted by means of the operated electric motor so that a newly adjusted actual travel difference between a first adjustment travel of the driver brake force transmission element from its first initial position and a newly adjusted second adjustment travel of the electric motor force transmission element from its second initial position corresponds to a preset target travel difference. Thus, the advantageously improved control device can be well used for travel difference control.

[0010] During initial operation, the rotor of the electric machine can be set, for example, in a rotational motion at a constant speed from its rotor initial position. This enables reliable "catch-up" of the motor force transmission element that has been adjusted from its second initial position while the motor is in its inactive mode.

[0011] An electric brake booster for a vehicle brake system also achieves the advantages explained above, which is arranged or can be arranged upstream of a master brake cylinder of the vehicle brake system and is equipped with such a control device, an electric motor that can be controlled by means of the control device, a driver brake force transmission element that can be adjusted from its first initial position by means of the driver brake force, and an electric force transmission element that can be adjusted from its second initial position by means of operation of the electric motor and by means of the driver brake force transmission element that can be adjusted from its first initial position by at least a threshold travel.

[0012] Furthermore, a corresponding method for activating an electric brake booster of a vehicle brake system also offers the above-mentioned advantages. It is expressly pointed out that the method can be improved according to the above-mentioned specific embodiment of the control device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Further features and advantages of the invention are explained below with reference to the accompanying drawings.

[0014] Figure 1 A schematic diagram of an electric brake booster is shown for explaining the mode of operation of an embodiment of the control device; and

[0015] Figure 2a and 2b A flow chart and a coordinate system are shown for explaining a specific embodiment of a method for activating an electric brake booster of a vehicle system. DETAILED DESCRIPTION

[0016] Figure 1 A schematic diagram of an electric brake booster is shown to explain the mode of operation of an embodiment of the control device.

[0017] Figure 1 The schematically shown electric brake booster 10 is / can be connected upstream of a master brake cylinder 12 of a vehicle brake system (not shown in detail). The usability of the control device 14 interacting with the brake booster 10 is neither limited to a particular brake booster type of brake booster 10 nor to a particular brake system type of a vehicle brake system or to a specific vehicle type / motor vehicle type of a vehicle / motor vehicle equipped with a vehicle brake system. Alternatively, the control device 14 can interact with (almost) every brake booster type that includes at least one electric motor 16 that can be controlled by the control device 14, a driver brake force transmission element 18 and an electric motor force transmission element 20. The brake booster 10 can be, in particular, an electromechanical brake booster 10. The control device 14 can optionally be a component of the brake booster 10 or a device that can be operated outside the brake booster 10.

[0018] Driver brake force transmission element 18 is understood to be a component of brake booster 10 which transmits the driver brake force F driver The first (forceless) initial position of the driver braking force transmission element 18 is set / adjustable. For this purpose, the driver braking force transmission element 18 is connected / connectable to the brake actuating element 22 (directly or indirectly), so that the driver braking force F applied by the driver of the vehicle / motor vehicle to the brake actuating element 22 is driver The brake force transmission element 18 is transmitted / transmittable to the driver, while the driver's brake force transmission element 18 is in its first initial position when the driver does not operate the brake actuating element 22. The driver's brake force transmission element 18 can be, in particular, an input rod 18. The brake actuating element 22 can be, for example, a brake pedal 22.

[0019] The electromechanical force transmission element 20 is a component of the brake booster 10 which is connected (directly or indirectly) to the motor 16 so that the electromechanical force transmission element 20 is operated by the motor 16 due to the motor force F transmitted to the electromechanical force transmission element 20. motor The motor force transmission element 20 is usually connected to the motor 16 via a transmission device (not shown). The motor force transmission element 20 can be, for example, a valve body (Boost Body) 20. However, when the driver brake force transmission element 18 (via the driver brake force F driver ) from its first initial position at least by a preset threshold travel Δs max During adjustment, the electric force transmission element 20 can also be adjusted together with the driver brake force transmission element 18, which is also adjusted in the direction of the master brake cylinder 12. Thus, at least one adjustable piston (not shown) of the master brake cylinder 12 can be adjusted by means of the driver brake force F driver And with the help of motor force F motor Only when the motor force F motor is equal to zero, and the first adjustment travel of the driver braking force transmission element 18 from its first initial position is less than the threshold travel Δs max The motor force transmission element 20 is usually in its second initial position only when the driver brakes the force transmission element 18 from its first initial position by a threshold travel Δs max The adjustment starts with the joint adjustment movement of the motor force transmission element 20. Figure 1 Stops 24 a and 24 b , which are only schematically shown in FIG. 2 , may be formed on driver braking force transmission element 18 and / or on electric motor force transmission element 20 .

[0020] Optionally, brake booster 10 may also have at least one further force transmission element 26, for example an output rod 26, which is arranged downstream of driver brake force transmission element 18 and motor force transmission element 20, so that further force transmission element 26 is further transmitted to the driver brake force F driver and / or motor force F motor Adjustment can be made in the direction of the master brake cylinder 12. If necessary, a (powerless) third initial position is also defined for the further force transmission element 26, at which the driver's braking force F driver and motor force F motor =0, the further force transmission element 26 is in this third initial position. The additional element 28, for example, in particular the reaction disk 28, may also be arranged between the driver brake force transmission element 18, the motor force transmission element 20 and the further force transmission element 26, so that the driver brake force F driver and motor force F motor “Additive to” the further force-transmitting element 26 .

[0021] Typically, the brake booster 10 also has at least one travel sensor 18a and 20a of its driver brake force transmission element 18 and / or of its motor force transmission element 20, which is designed to output at least one travel sensor signal 18s and 20s, respectively, which varies as a function of a first adjustment travel of the driver brake force transmission element 18 from its first initial position and / or as a function of a second adjustment travel of the motor force transmission element 20 from its second initial position. Optionally, at least one further travel sensor 26a can also be arranged on the brake booster 10 for the further force transmission element 26, by means of which at least one travel sensor signal 26s can be outputted which varies as a function of a third adjustment travel of the further force transmission element 26 from its third initial position. It is expressly pointed out that at least one travel sensor 18a, 20a and 26a can also be designed to output a travel sensor signal 18s, 20s or 26s which varies periodically as a function of the respective adjustment travel of the associated force transmission element 18, 20 or 26 from its initial position. This type of travel sensor is also referred to as a "periodic travel sensor". The electric machine 16 is usually also equipped with at least one electric machine sensor 16 a , such as a rotor position sensor, a rotational speed sensor and / or a motor current sensor.

[0022] The control device 14 has an electronic device 14a, which is designed and / or programmed to detect, at least with the aid of at least one travel sensor signal 18s, 20s and 26s, whether the motor force transmission element 20 is adjusted from its second initial position, although the motor 16 is in its inactive mode, at least during the inactive mode of the motor 16. A particularly advantageous processing method for detecting whether the motor force transmission element 20 is adjusted from its second initial position, although the motor 16 is in its inactive mode, is also discussed below. The inactive mode can be understood as a non-energized mode and / or a shutdown mode of the motor 16, in which the motor 16 is located before the motor 16 is activated / started. In particular, while the motor 16 is in its inactive mode, the (not shown) rotor of the motor 16 can be in its non-energized rotor initial position relative to the stator of the motor 16, i.e., in the position in which the rotor (usually) is located before the motor 16 is activated / started. Since the electronic device 14a is designed to control the electric motor 16 by means of at least one control signal 14s, the electronic device 14a usually automatically has information whether the electric motor 16 is in its inactive mode. However, the electronic device 14a can also be designed / programmed to determine or verify that the electric motor 16 is possibly in its inactive mode by means of at least one motor sensor signal 16a.

[0023] If the electronic device 14a detects that the motor force transmission element 20 was adjusted from its second initial position while the motor 16 was in its inactive mode, the electronic device 14a is designed / programmed to transfer the motor 16 into a so-called initial operation by means of at least one control signal 14s. The initial operation to which the motor 16 can be transferred by means of the electronic device 14a is to be understood as an operation of the motor 16 during which the rotor is set into a rotational movement from its currentless rotor initial position, which can be described as a "catch-up movement" of the rotor relative to the motor force transmission element 20 that has been adjusted from its second initial position. In particular, during the initial operation of the motor 16, the rotor can be set into a rotational movement at a constant speed from its currentless rotor initial position.

[0024] Furthermore, the electronic device 14a is designed / programmed to check, by means of at least one motor sensor signal 16a, whether the motor torque of the motor 16 exceeds a predefined limiting motor torque and / or whether the gradient of the motor torque exceeds a predefined limiting gradient. The motor torque of the motor 16 remains relatively low as long as the rotor of the motor 16 during its “catch-up movement” only “follows” the motor force transmission element 20 adjusted from its second initial position. The motor torque of the motor 16 increases significantly only when the rotor of the motor 16 “catches up” with the motor force transmission element 20, since, starting from this operating point of the motor 16, a significant counterpressure in the master brake cylinder 12 opposes further rotational movement of the rotor of the motor 16. By monitoring the motor torque of the motor 16 and / or the gradient of the motor torque, the electronic device 14a can identify and detect an operating point of the motor 16 in which the motor 16 “catches up” with the motor force transmission element 20.

[0025] Therefore, the electronic device 14a is also designed / programmed to (directly / immediately) end the initial operation of the motor 16 from the time of recognizing that the motor torque of the motor 16 exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient. Therefore, when the motor torque of the motor 16 exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient, the initial operation of the motor 16 ends (directly / immediately).

[0026] Thus, the configuration / programming of the control device 14 / its electronic system 14a described here always enables a regular “follow-up” of the rotor of the electric motor 16 when the electric motor 16 is already adjusted from its second starting position due to the actuation of the brake actuating element 22 by the driver of the vehicle / motor vehicle, even though the electric motor 16 is in its inactive mode. Thus, the control device 14 / its electronic system 14a can advantageously react to an actuation of the brake actuating element 23 which has already occurred before the activation / startup of the electric motor 16 of the brake booster 10. The “follow-up” of the rotor of the electric motor 16 as a reaction to the electric motor force transmission element 20 being adjusted from its second starting position (substantially) does not trigger a haptically perceptible reaction to the actuation of the brake actuating element 22 by the driver. As a result, the driver is also not irritated by a change in the properties / stiffness of the brake actuating element 22 which is perceptible to the driver.

[0027] Preferably, the electronic device 14a is additionally designed and / or programmed to determine the cumulative rotation angle of the rotor from its non-energized rotor initial position to the position of the rotor at an identification time point, at which the electronic device 14a identifies that the motor torque of the motor 16 exceeds the limit motor torque and / or the gradient of the motor torque exceeds a preset limit gradient. Determining the cumulative rotation angle can optionally be estimating the cumulative rotation angle during initial operation by controlling the motor 16 by the electronic device 14a or reading the cumulative rotation angle by means of at least one motor sensor signal 16s. In particular, the cumulative rotation angle can be determined by adding the number of revolutions of the rotor when "following". Therefore, the design / programming of the electronic device 14a described here provides a program, by which it can also be identified how far the rotor must "follow" the motor force transmission element 20 that has been adjusted from its second initial position before activating / starting the motor 16.

[0028] Thus, the correspondingly designed / programmed electronic device 14a can also use the accumulated rotation angle to determine a first position statement about the first position of the driver's brake force transmission element 18 at the recognition time and / or about the first adjustment path of the driver's brake force transmission element 18 adjusted from its first initial position at the recognition time, a second position statement about the second position of the motor force transmission element 20 at the recognition time and / or about the second adjustment path of the motor force transmission element 20 adjusted from its second initial position at the recognition time, and / or a third position statement about the third position of the further force transmission element 26 at the recognition time and / or about the third adjustment path of the further force transmission element 26 adjusted from its third initial position at the recognition time. If the initial operation of the electric motor 16 ends / decelerates (almost) directly / immediately at the recognition time, the first position statement, the second position statement and / or the third position statement can each also be interpreted as a current position statement, whose value is valid even after the initial operation of the electric motor 16 ends / is interrupted. Thus, the embodiment of control device 14 / its electronic system 14a described here also enables travel sensor initialization in the event of an actuation of brake actuating element 22 by the driver before activation / starting of electric motor 16. Furthermore, the procedure executed by control device 14 / its electronic system 14a for initializing the travel sensor system of brake booster 10 does not require any expansion / modification of the sensor system of brake booster 10. Of course, the procedure can also be used in other cases, which are however not discussed here.

[0029] Optionally, the electronic device 14a can also be designed / programmed to determine the first position information, the second position information and / or the third position information while taking into account the accumulated rotation angle and additionally taking into account the at least one travel sensor signal 18s, 20s and 26s. This also applies to the case where the at least one travel sensor 18a, 20a and 26a is each designed as a "periodic travel sensor" to output a travel sensor signal 18s, 20s or 26s that changes periodically as a function of a first adjustment travel of the driver brake force transmission element 18 from its first initial position, as a function of a second adjustment travel of the motor force transmission element 20 from its second initial position and / or as a function of a third adjustment travel of the further force transmission element 26 from its third initial position. Thus, the control device 14 can interact with a sensor type that can be installed relatively inexpensively and relatively simply as the at least one travel sensor 18a, 20a and 26a. As will be further explained below using examples, the control device 14 / its electronic device 14a can determine the first position statement, the second position statement and / or the third position statement more accurately and more reliably using a program executable therewith than would be possible using only at least one such travel sensor 18a, 20a and 26a.

[0030] As an advantageous development, the electronic device 14a can additionally be designed and / or programmed to determine, with the aid of the first position information and the second position information, an initial travel difference Δs between a first adjustment travel of the driver's brake force transmission element 18 from its first initial position and a second adjustment travel of the motor force transmission element 20 from its second initial position at the identification time. It is thus possible to dispense with equipping the brake booster 10 with a travel difference sensor, which as a motion sensor can usually only be installed with difficulty due to the need for at least one moving cable. This contributes to cost savings and to miniaturization of the brake booster 10 interacting with the control device 14.

[0031] Furthermore, the electronic device 14a can additionally be designed and / or programmed to operate the electric motor 16 in a travel difference control mode by means of at least one control signal 14s after the initial operation has ended, during which the motor force transmission element 20 is adjusted / adjustable by means of the electric motor 16 operated in the travel difference control mode so that a newly adjusted actual travel difference between a first adjustment travel of the driver's brake force transmission element 18 from its first initial position and a newly adjusted second adjustment travel of the motor force transmission element 20 from its second initial position corresponds to a predefined target travel difference. After the travel sensor is initialized, the electric motor 16 can thus be further operated by the electronic device 14a so that the driver who actuates the brake actuating element 22 has a pleasant and standard brake actuation feel / pedal feel.

[0032] Figure 2a and 2b A flow chart and a coordinate system are shown for explaining a specific embodiment of a method for activating an electric brake booster of a vehicle system.

[0033] The method described below can be used, for example, Figure 1 The method is performed by means of the brake booster explained above. However, it should be pointed out that the feasibility of the method is not limited to this type of brake booster. Alternatively, the method can be performed with the aid of (almost) any brake booster that is pre-placed / can be pre-placed on a master brake cylinder of a vehicle brake system and is equipped with an electric motor, a driver brake force transmission element that is adjusted / adjustable from its first initial position by means of the driver's brake force, and an electric force transmission element that is adjusted / adjustable from its second initial position by means of the operation of the electric motor and by means of a driver brake force transmission element that is adjusted from its first initial position at least by a preset threshold stroke. The electric force transmission element can, for example, be connected to the electric motor via a transmission. The characteristics of the driver brake force transmission element and the electric force transmission element have been described above. In addition, the feasibility of the method is neither limited to a specific brake system type of a vehicle brake system nor to a specific vehicle type / motor vehicle type of a vehicle / motor vehicle equipped with a vehicle brake system.

[0034] At the beginning of the method, method step S1 is performed before the electric motor of the brake booster is activated / started. In method step S1, it is determined whether the motor force transmission element is in its second initial position while the motor is in its inactive mode. Optionally, method step S0 can also be performed before method step S1, in which it is determined / verified whether the motor is actually in its inactive mode. For this purpose, for example, it can be checked with the aid of at least one motor sensor signal of at least one motor sensor of the motor, for example, in particular a rotor position sensor of the motor, whether the rotor of the motor is in its non-energized rotor initial position relative to the stator of the motor.

[0035] To carry out method step S1, at least one travel sensor signal of at least one travel sensor of the motor force transmission element and / or the driver brake force transmission element is evaluated. In particular, at least one travel sensor signal of at least one "periodic travel sensor" can be evaluated, which periodically outputs a travel sensor signal that changes periodically as a function of a first adjustment travel of the driver brake force transmission element from its first initial position, as a function of a second adjustment travel x of the motor force transmission element from its second initial position, and / or as a function of a third adjustment travel of a further force transmission element downstream of the driver brake force transmission element and the motor force transmission element from its third initial position. This is accomplished by Figure 2bA coordinate system is shown, the abscissa of which shows the second adjustment travel x of the motor force transmission element, and the ordinate of which shows the (second) value I of the (second) travel sensor signal of the (second) travel sensor associated with the motor force transmission element.

[0036] If the first travel sensor associated with the driver brake force transmission element and the second travel sensor associated with the motor force transmission element are each a "periodic travel sensor", then in method step S1 it can be checked whether a first value of a first travel sensor signal of the first travel sensor is within a first comparison value range predefined for bringing the driver brake force transmission element into its first initial position and at the same time whether a second value I of a second travel sensor signal of the second travel sensor is also within a second comparison value range predefined for bringing the motor force transmission element into its second initial position. If the associated force transmission element is still adjusted from its associated initial position (see Figure 2b ), then in each case a "periodic travel sensor" is used for the first travel sensor and the second travel sensor, a single value of one of the two travel sensor signals can also be within the associated comparison value range. However, in the case of using two "periodic travel sensors", both values ​​of the travel sensor signals of these travel sensors are usually only within the comparison value range at the same time, as long as the driver brake force transmission element and the electric motor force transmission element are also held together in their initial position.

[0037] If it is determined in method step S1 that the motor force transmission element is adjusted from its second starting position despite the motor being in its inactive mode, the method continues with at least method steps S2 and S3. Otherwise, the method may end and may start again with method step S1 before later activation / later start of the motor.

[0038] As method step S2, the motor is transferred to an initial operation and operated, during which the rotor of the motor rotates from its initial position. During the initial operation, method step S3 is also performed at least once, in which it is determined by means of at least one motor sensor signal whether the motor torque of the motor exceeds a preset limit motor torque and / or whether the gradient of the motor torque exceeds a preset limit gradient. If it is detected that the motor torque of the motor exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient, method step S2 / initial operation is ended / interrupted (directly / immediately).

[0039] Therefore, the execution of method steps S1 to S3 also enables a procedure for advantageously "following up" or "catching up" with the motor force transmission element which has already been adjusted from its second initial position before the activation / start of the electric motor. By (almost) directly / immediately ending / interrupting the initial operation of the electric motor, it is also ensured that the driver brake force transmission element and the motor force transmission element are also (essentially) in the same position after the end of the initial mode as at the detection time point at which it was detected that the motor torque of the electric motor exceeded the limit motor torque and / or the gradient of the motor torque exceeded the limit gradient. This can be advantageously used for initializing the travel sensor, as will become clear from the subsequent description.

[0040] Therefore, as an advantageous development, the cumulative rotation angle of the rotor from its initial position to the position of the motor at the identification time can be determined in method step S4. In method step S4, the cumulative rotation angle can optionally be estimated by controlling the motor during initial operation or read from at least one motor signal.

[0041] In a further method step S5, the accumulated rotational angle can be used to determine a first position statement about a first position of the driver brake force transmission element at the time of identification and / or about a first adjustment path of the driver brake force transmission element adjusted from its first initial position at the time of identification, a second position statement about a second position of the motor force transmission element at the time of identification and / or about a second adjustment path x of the motor force transmission element adjusted from its second initial position at the time of identification, and / or a third position statement about a third position of the further force transmission element at the time of identification and / or about a third adjustment path of the further force transmission element adjusted from its third initial position at the time of identification. Optionally, the first position statement, the second position statement and / or the third position statement can be determined taking into account the accumulated rotational angle and taking into account additionally at least one travel sensor signal of at least one travel sensor associated with the driver brake force transmission element, the motor force transmission element and / or the further force transmission element.

[0042] If the second travel sensor signal is used Figure 2b As can be seen from the value I plotted in the coordinate system of , the second travel sensor signal varies with a period π, which is only 10 mm by way of example. Therefore, the measured value I of the second travel sensor signal at the identification time point (or immediately after the identification time point) is measured For all second adjustment travels x of the motor force transmission element, the following applies: x=f(I measured )+n*π, where n={0, 1, 2, 3...}.

[0043] for Figure 2bFor example, this applies to second adjustment travels x of approximately 3 mm, 13 mm, 23 mm, 33 mm, ... However, with the aid of the accumulated rotation angle (determined in method step S4), an estimated value x of the second adjustment travel x can be estimated when performing method step S5. estimated Typically, the estimated value x of the second adjustment stroke x estimated by means of the accumulated rotation angle is estimated is greater than the current / actual second adjustment travel x of the motor force transmission element from its second initial position at the recognition time (or immediately after the recognition time). exact , since the transmission stiffness of the transmission, via which the electromechanical force transmission element is mostly connected to the motor, and the time period for detecting the exceeding of the limiting motor torque and / or limiting gradient contribute to the (minimum) increase in the accumulated rotation angle determined in method step S4. It can therefore be inferred that the current second adjustment path x of the electromechanical force transmission element from its second initial position exact is smaller than the estimated value x estimated by the cumulative rotation angle estimated , but with the estimated value x estimated The distance is d<<π. With the processing method described here, it is possible to estimate the value x estimated It is recognized that the measured value I of the second travel sensor signal measured It is located within "which cycle π" of the second stroke sensor.

[0044] By means of the second adjustment path x of the electromechanical force transmission element adjusted from its second starting position at the identification time, for example by means of the current second adjustment path x exact It is also possible to determine a first adjustment travel of the driver's brake force transmission element adjusted from its first initial position at the identification time, since the relationship between the second adjustment travel x and the first adjustment travel is usually known due to the knowledge of at least one mechanical stop on the driver's brake force transmission element and / or the motor force transmission element. For example, as the first adjustment travel of the driver's brake force transmission element adjusted from its first initial position at the identification time, the second adjustment travel x of the motor force transmission element adjusted from its second initial position at the identification time and the threshold travel Δs max Alternatively, a corresponding first adjustment stroke which is greater than the estimated value x estimated by means of the accumulated rotation angle may be selected from the set of first adjustment strokes corresponding to the measured values ​​of the first stroke sensor signal. estimated , but with the estimated value x estimated The distance is less than the threshold travel Δs max Thus, a third adjustment path of the force transmission element adjusted from its third starting position at the identification time can also be calculated.

[0045] In (optional) method step S6, an initial stroke difference between a first adjustment stroke of the driver's brake force transmission element from its first initial position and a second adjustment stroke of the motor force transmission element from its second initial position can be determined with the aid of the first position specification and the second position specification. In a further (optional) method step S7, the motor can be operated in a stroke difference adjustment operation after the initial operation is completed, during which the motor force transmission element is adjusted with the aid of the running motor so that the newly adjusted actual stroke difference between the first adjustment stroke of the driver's brake force transmission element from its first initial position and the newly adjusted second adjustment stroke of the motor force transmission element from its second initial position corresponds to a preset target stroke difference. Thus, a normal adjustment based on a specific initial stroke difference can be performed with the aid of method step S7. In order to ensure a fast adjustment of the target stroke difference, the speed of the motor can also be preset depending on the position. The motor can, for example, be controlled at its maximum speed at an initial stroke difference between 4 mm and 12 mm and decelerated to a more sensitive speed when the newly adjusted actual stroke difference approaches the desired target stroke difference.

Claims

1. A control device (14) for an electric brake amplifier (10) of a vehicle brake system, comprising: An electronic device (14a) by means of which, based on at least one motor sensor signal (16s) of at least one motor sensor (16a) of a motor (16) of the brake force amplifier (10) arranged upstream of the master brake cylinder (12), it is possible to detect that the motor torque of the motor (16) exceeds a preset limit motor torque and / or that the gradient of the motor torque exceeds a preset limit gradient; It is characterized in that By means of the electronic device (14a), at least based on at least one travel sensor signal (20s) of at least one travel sensor (20a) of the motor force transmission element (20) of the brake booster (10) and / or at least one travel sensor signal (18s) of at least one travel sensor (18a) of the driver brake force transmission element (18) of the brake booster (10), it is possible to recognize that when the motor (16) is in its inactive mode, the motor force transmission element (20) is adjusted from its second initial position, the motor force transmission element being able to be adjusted both by the operation of the motor (16) and by at least a preset threshold travel (Δs) from its first initial position. max ) to adjust the driver braking force transmission element (18); The electric motor (16) is switched to an initial operation and operated, if necessary by means of the electronic device (14a), during which the rotor of the electric motor (16) is set into a rotational movement from its rotor initial position, and The electronic device (14a) is designed and / or programmed to terminate the initial operation of the motor (16) when the motor torque of the motor (16) exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient.

2. The control device (14) according to claim 1, wherein: The control device (14) is additionally designed and / or programmed to estimate during the initial operation or read from the at least one motor sensor signal (16s) the cumulative rotation angle of the rotor from its rotor initial position to the position of the rotor at an identification time point based on the control of the motor (16) by means of the electronic device (14a), at which point in time it is possible to identify with the aid of the electronic device (14a) that the motor torque of the motor (16) exceeds the limit motor torque and / or that the gradient of the motor torque exceeds the preset limit gradient; and Taking into account at least the accumulated rotation angle, determine: a first position specification of the first position of the driver braking force transmission element (18) at the recognition time and / or of a first adjustment path of the driver braking force transmission element (18) adjusted from its first initial position at the recognition time, a second position statement about the second position of the electromechanical force transmission element (20) at the identification time point and / or about a second adjustment path (x) of the electromechanical force transmission element (20) adjusted from its second initial position at the identification time point, and / or A third position specification of a further force transmission element (26) arranged downstream of the driver brake force transmission element (18) and the motor force transmission element (20) at the recognition time and / or a third position specification of a third adjustment path of the further force transmission element (26) adjusted from its third initial position at the recognition time.

3. The control device (14) according to claim 2, wherein: The electronic device (14a) is designed and / or programmed to determine the first position statement, the second position statement and / or the third position statement taking into account the accumulated rotation angle and additionally taking into account at least one travel sensor signal (18s, 20s, 26s) of at least one travel sensor (18a, 20a, 26a) associated with the driver brake force transmission element (18), the motor force transmission element (20) and / or the further force transmission element (26).

4. The control device (14) according to claim 2 or 3, wherein: The electronic device (14a) is additionally designed and / or programmed to determine an initial travel difference (Δs) between a first adjustment travel of the driver braking force transmission element (18) from its first initial position and a second adjustment travel (x) of the motor force transmission element (20) from its second initial position with the aid of the first position description and the second position description, and to operate the motor (16) in a travel difference adjustment operation after the initial operation is completed, during which the motor force transmission element (20) can be adjusted with the aid of the operating motor (16) so that a newly adjusted actual travel difference between the first adjustment travel of the driver braking force transmission element (18) from its first initial position and the newly adjusted second adjustment travel (x) of the motor force transmission element (20) from its second initial position corresponds to a preset target travel difference.

5. A control device (14) according to any one of the preceding claims, wherein: During initial operation of the motor (16), the rotor is set into rotational motion at a constant speed from its rotor initial position.

6. An electric brake amplifier (10) for a vehicle brake system, the electric brake amplifier being arranged in front of or being capable of being arranged in front of a master brake cylinder (12) of the vehicle brake system, comprising: A control device (14) according to any one of the preceding claims; the electric motor (16) being controllable by means of the control device (14); The driver brake force transmission element (18) can be used to transmit the driver brake force (F driver ) is adjusted from its first initial position; and The electromechanical force transmission element (20) can be moved both by the operation of the motor (16) and by moving the motor from its first initial position at least by the threshold travel (Δs max ) is adjusted from its second initial position.

7. A method for activating an electric brake booster (10) of a vehicle braking system, comprising the following steps: At least with the aid of at least one travel sensor signal (20s) of at least one travel sensor (20a) of an electromechanical force transmission element (20) of a brake booster (10) upstream of a master brake cylinder (12) and / or at least one travel sensor signal (18s) of at least one travel sensor (18a) of a driver brake force transmission element (18) of the brake booster (20), it is determined whether the electromechanical force transmission element (20) is in its second initial position (S1) when the motor (16) of the brake booster (10) is in its inactive mode, the electromechanical force transmission element being able to be moved both by the operation of the motor (16) and by a travel distance (Δs) from its first initial position at least as far as a predetermined threshold value. max ) to adjust the driver braking force transmission element (18); in, If it is determined that the motor force transmission element (20) is adjusted from its second initial position when the motor (16) is in its inactive mode, the motor (16) is transferred to an initial operation and operated (S2), during which the rotor of the motor (16) rotates from its initial position and it is determined (S3) at least once with the aid of at least one motor sensor signal (16s) of at least one motor sensor (16a) of the motor (16) whether the motor torque of the motor (16) exceeds a preset limit motor torque and / or whether the gradient of the motor torque exceeds a preset limit gradient, and The initial operation is terminated if the motor torque of the motor (16) exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient.

8. The method according to claim 7, wherein: According to the control of the motor (16), during the initial operation, the accumulated rotation angle of the rotor from its rotor initial position to the position of the rotor at an identification time point is estimated or read from the at least one motor sensor signal (16s), at which time point it is identified that the motor torque of the motor (16) exceeds the limit motor torque and / or the gradient of the motor torque exceeds the limit gradient; and Taking into account at least the accumulated rotation angle, determine: a first position specification of the first position of the driver braking force transmission element (18) at the recognition time and / or of a first adjustment path of the driver braking force transmission element (18) adjusted from its first initial position at the recognition time, a second position statement about the second position of the electromechanical force transmission element (20) at the identification time point and / or about a second adjustment path (x) of the electromechanical force transmission element (20) adjusted from its second initial position at the identification time point, and / or A third position specification of a further force transmission element (26) arranged downstream of the driver brake force transmission element (18) and the motor force transmission element (20) at the recognition time and / or a third position specification of a third adjustment path of the further force transmission element (26) adjusted from its third initial position at the recognition time.

9. The method according to claim 8, wherein: The first position statement, the second position statement and / or the third position statement are determined taking into account the accumulated rotation angle and additionally taking into account at least one travel sensor signal (18s, 20s, 26x) of at least one travel sensor (18a, 20a, 26a) associated with the driver brake force transmission element (18), the motor force transmission element (20) and / or the further force transmission element (26).

10. The method according to claim 8 or 9, wherein: An initial travel difference (Δs) between a first adjustment travel of the driver braking force transmission element (18) from its first initial position and a second adjustment travel (x) of the motor force transmission element (20) from its second initial position is determined using the first position specification and the second position specification. max ), and the motor (16) is operated in a stroke difference adjustment operation after the initial operation is completed, during which the motor force transmission element (20) is adjusted by means of the running motor (16) so that a newly adjusted actual stroke difference between a first adjustment stroke of the driver braking force transmission element (18) from its first initial position and a newly adjusted second adjustment stroke (x) of the motor force transmission element (20) from its second initial position corresponds to a preset target stroke difference.

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