Improved actuation of electromechanical parking brakes, especially for motor vehicles

Abstract

The invention relates to an improved actuation of an electromechanical parking brake, in particular for a motor vehicle. A method for actuating an electromechanical parking brake, in particular for a motor vehicle, is proposed, comprising the following method steps: recognition of a user-side actuation request (11), preferably by means of a switch unit; establishment of a predefined clamping force (07) via a drive mechanism by moving at least one brake pad into a holding position relative to a brake disc or brake drum; activation of a locking mechanism (12) for fixing the brake pad in the holding position, preferably by means of a click-in in a ratchet wheel; elimination, in particular gradual reduction, of the clamping force provided by the drive mechanism (13); output of an actuation confirmation (14) to the user, preferably by means of an optical and / or acoustic output unit (01).

Description

Technical Field

[0001] This invention relates to a method for operating an electromechanical parking brake, particularly for motor vehicles. Furthermore, the invention relates to a controller for controlling the electromechanical parking brake. The invention also relates to an electromechanical parking brake. Background Technology

[0002] Electromechanical braking systems (EMBs) for motor vehicles are known. Here, by means of an electric drive mechanism, such as an electronically commutated motor (EC machine), brake pads are moved or shifted toward the brake disc or brake drum via a reduction gear and a rotary translational gear, such as a ball screw drive (KGT), to generate friction and thus braking force or deceleration. Conversely, brake pads can be moved or shifted away from the brake disc or brake drum to reduce or eliminate friction and the resulting deceleration. By adjusting the electric drive mechanism, the vehicle can thus generate and eliminate braking force according to the driver's expectations.

[0003] Furthermore, it is known that electromechanical braking systems are implemented with minimal or no self-locking. The aim is that, in the event of a malfunction in the electromechanical mechanism, the corresponding brake releases the braked wheels and allows continued driving, possibly with a warning to the driver or user regarding the malfunction or failure of the electromechanical brake. Additionally, it is known from the prior art that electromechanical braking devices can also function as parking brakes or vehicle parking brakes. Because parking brake or vehicle parking brake functions must be performed or maintained without energy, in the prior art, a target clamping force is set between the brake pads and the brake disc / drum by the electromechanical braking device, and then the mechanical action path from the electric drive mechanism to the clamping mating parts, i.e., to the brake pads and brake disc / drum, is locked. This locking can be based on friction or by means of form-locking.

[0004] DE 198 54 105 A1 is known from the prior art. It describes a method for a user to operate an electric parking brake, wherein an adjustment command for tightening or loosening the parking brake is output by means of an unlocked pulse sensor, such as a button. The execution of the command and / or the system's prescribed function or malfunction in the state of the parking brake is fed back and signaled by means of an electrically operable, for example, bistable, display element that is held in the corresponding switching position without consuming energy.

[0005] Because electromechanical drive mechanisms are commonly found in both service and parking brakes in electromechanical braking systems, the brake pads may have very different initial positions relative to the brake disc or drum at the time of the user's request to operate or activate the parking brake. This results in the components involved, such as the drive mechanism, being subjected to excessively high loads and consuming too much energy during the statically preset movement of the brake pads used to activate or operate the electromechanical parking brake, and also leads to the parking brake operation or activation ending at different speeds. Therefore, in addition to causing discomfort to the user when operating or activating the parking brake at significantly different speeds, it can also lead to unnecessary or excessive wear on the components and parts of the electromechanical parking brake. Summary of the Invention

[0006] In this context, the objective of the present invention is to overcome the shortcomings of the prior art, and in particular to achieve improvements in the operation of electromechanical parking brakes.

[0007] The method for operating an electromechanical parking brake according to the present invention allows for dynamic design of the operation, i.e., without pre-setting the operation or individual operation steps themselves, but rather pre-setting a time or duration (i.e., a time period), and furthermore, the operation ends, and feedback must be output to the user. This enables the actual operation or activation of the electromechanical parking brake to be performed optimally and resource-efficiently or material-efficiently within the available time period between the operation request and the output of operation confirmation. Furthermore, it achieves the particular advantage that the user or user always receives operation confirmation output according to the user-side operation request after a fixed time period, thereby establishing a correspondingly high level of trust among the user in the safe and reliable braking effect of the electromechanical parking brake.

[0008] The method according to the invention for operating an electromechanical parking brake, particularly for motor vehicles, includes the following steps, which are preferably, but not necessarily, performed in the order mentioned below:

[0009] Identify the control requirements for operating the electromechanical parking brake, preferably on the user side and preferably implemented through a switching unit.

[0010] The driving mode indicated by "P" at the driving mode selection unit can be understood as the operation of the switch unit. Alternatively, in addition to activating the switch unit, the operation request for the electromechanical parking brake can also be triggered by other user-side actions that do not directly require activation of the parking brake switch unit. For example, it could be triggered by the driver unlocking the door, opening the driver's door, or leaving the driver's seat. It is also possible that, within the scope of the automatic parking or parking exit process, the operation request is automatically generated after reaching the final parking position.

[0011] A preset clamping force is established via a preferred electromechanical drive mechanism by moving at least one brake pad relative to the brake disc or brake drum to a holding position. A locking mechanism is activated to secure the brake pad in the holding position, preferably by the engagement of a pawl in a ratchet. The clamping force provided by the drive mechanism is then eliminated, particularly gradually reduced. Eliminating the clamping force provided by the drive mechanism is preferably achieved by eliminating or reducing the motor torque of the drive mechanism. Operation confirmation is preferably output to the user via an optical and / or acoustic output unit.

[0012] According to the present invention, regardless of the initial state of the electromechanical parking brake, an operation confirmation is output after a fixed period of time based on the operation requirements, wherein, at the time of output or at the point of output, the locking mechanism is activated and / or the clamping force of the drive mechanism is eliminated. Therefore, it is particularly advantageous to achieve not only a constant, especially a constant and rapid, feedback output to the user through successful activation or operation of the parking brake, but also to execute each operation step optimally or at least suitably according to the initial state of the electromechanical parking brake.

[0013] In an advantageous first embodiment of the method, it can be stipulated that, prior to output control confirmation, the locking mechanism is checked over a fixed period of time, particularly by examining the motion state of the drive mechanism. As already implemented above, a suitable electric motor can be used as the drive mechanism. If the locking mechanism is activated and thus the electromechanical parking brake is actuated, an equilibrium state is formed when or after the clamping force is reduced by the drive mechanism. Once this equilibrium state is reached, no further movement can be provided on the drive mechanism side. Thus, it can be reliably determined, through the motion state of the drive mechanism, whether the parking brake is correctly actuated and whether the locking mechanism is activated.

[0014] For example, the movement of the drive mechanism can be identified by assessing the voltage and current states on the corresponding motor. Additional or alternative sensor devices may also be provided to detect and inspect the movement state of the drive mechanism.

[0015] Another advantageous design of this method is that the establishment of the preset clamping force and / or the activation of the locking mechanism can be performed energy-optimally, especially as quickly as possible. From the point when the locking mechanism is activated and the clamping force from the drive mechanism is completely eliminated, the electric drive is no longer operated, and therefore no current and electrical energy are required. Therefore, it may be particularly advantageous, for energy-optimal activation of the electromechanical parking brake, to perform the establishment of the preset clamping force and the activation of the locking mechanism, as well as the elimination or reduction of the clamping force if necessary, as quickly as possible. This results in the establishment of the preset clamping force, the activation of the locking mechanism, and the subsequent elimination of the clamping force occurring at a time when the parking brake is operated, even if the clamping force is already partially or completely present in the initial state, for example when the service brake pedal is actuated. This ensures that the establishment of the preset clamping force, the activation of the locking mechanism, and the subsequent elimination of the clamping force have already ended significantly before the end of the fixed time period. In this case, according to the invention, the operation confirmation is still output only after the fixed time period has expired, so that if the output is performed too quickly or too early, the user will not be disturbed by successful operation.

[0016] Conversely, a fixed time period can be preset or defined so that clamping force can be established from a fully open electromechanical brake even in the initial state, activating the locking mechanism, and the clamping force can be released if necessary before output operation confirmation. Other influencing factors, such as the operating temperature and / or voltage level of the electromechanical parking brake, can also be considered here to ensure reliable and safe activation within the fixed time period under any circumstances.

[0017] In another equally advantageous embodiment, the load for establishing the preset clamping force and / or activating the locking mechanism can be optimized, particularly to make full use of the available fixed time period. This advantageously allows for the activation or actuation of the parking brake, taking into account the corresponding initial state of the electromechanical parking brake, so that the entire available time period or individual intervals are utilized as fully as possible. This avoids large loads on the drive mechanism, especially on the motor side. The rotational speed can be increased accordingly slowly and then decreased slowly after reaching the preset clamping force. Furthermore, this avoids high acceleration on the locking mechanism side. The current required to operate the locking mechanism can be adjusted accordingly so that the movable part of the locking mechanism does not rigidly move into the mechanical end stop.

[0018] As described above, another particularly advantageous design of this method can specify that the operation of the drive mechanism and / or the locking mechanism is determined or optimized based on the initial state of the electromechanical parking brake and taking into account the time period. For example, when all available fixed time periods should be fully utilized, the initial state can be detected, and the drive mechanism for establishing and disengaging the clamping force and the locking mechanism can be operated in an optimized manner based on the initial state, such as energy-optimized and load-optimized.

[0019] As already mentioned, an advantageous implementation of this method can be to determine the initial state of the parking brake by determining the position of the drive mechanism and / or at least one brake pad and / or the level of the supply voltage to the parking brake and / or the temperature of the parking brake. Regarding the temperature of the parking brake, it is particularly advantageous to detect the operating temperature of the electromechanical mechanism.

[0020] The aforementioned indicators are particularly well-suited for detecting, or at least approximating, the initial state as accurately as possible, based on static conditions and the dynamically variable characteristics of the electromechanical parking brake. Therefore, based on the detection and evaluation of these characteristics and measurements, the activation of the parking brake and the various methodological steps, given the initial state, can be advantageously optimized or adapted to ensure that activation is still complete at the end of a fixed time period and that operational confirmation can be output.

[0021] The present invention also relates to a controller for controlling an electromechanical parking brake, comprising a switching unit connected to a user-side operation request for the parking brake, an optical and / or acoustic output unit for outputting operation confirmation to the user via operation of the parking brake, and at least one connection to a sensor device for identifying and / or monitoring the state of the parking brake. According to the invention, the controller is designed to activate the parking brake and, after a fixed period of time, generate an operation confirmation output based on the operation request, wherein, upon outputting the operation confirmation, a locking mechanism is activated and / or the clamping force of the drive mechanism is eliminated. The controller according to the invention ensures, on the one hand, that the parking brake is activated or operated, and on the other hand, reliably and understandably outputs operation confirmation to the user after a fixed time or a fixed period of time.

[0022] This makes it particularly advantageous to optimize the parking brake based on its initial state while adhering to or maintaining a fixed time period.

[0023] In an advantageous implementation of the controller, it may be specified that the controller is designed to perform a method according to one of the above-described embodiments.

[0024] The invention also includes an electromechanical parking brake, particularly for motor vehicles, wherein the electromechanical parking brake includes a controller according to one of the embodiments described above. As described above, the parking brake according to the invention generates and outputs constant feedback (in the form of operation confirmation) that is particularly advantageous to the user, wherein the possibility of optimally executing the activation of the parking brake and, in particular, relating it to the initial state is simultaneously provided. Attached Figure Description

[0025] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention and with reference to the accompanying drawings.

[0026] Figure 1 The process for activating the electromechanical parking brake over time, according to different implementation methods, is shown.

[0027] The same elements or elements with the same function are given the same reference numerals in the drawings. Detailed Implementation

[0028] Figure 1 A time-resolved flowchart for operating or activating an electromechanical parking brake is shown. Time axis 10 shows the states, characteristics, and method steps present at specific points in time. At time t1, the optical output unit 01, exemplarily shown with a common parking brake symbol, is not activated, i.e., it is not turned on or illuminated from behind. The first function curve symbolizes the state of output unit 01 or the function curve of the output unit during the time period between time t1 and time t10.

[0029] As can be seen, by activating or illuminating the optical output unit 01 from behind, an operation confirmation is output to the user at a fixed time point t10. Therefore, a fixed time period t10-t1 is preset, during which the parking brake is activated and an operation confirmation is output. The electromechanical parking brake is activated upon receiving the user's operation request 03. Figure 1 As can be seen in the function curve shown in the signal sequence at the bottom of the time diagram, at time point t1, operation requirement 11 is implemented through a switching unit not shown in detail. Similarly, in Figure 1 The diagram shows the first clamping force curve 04, the second clamping force curve 05, and the third clamping force curve 06. In the first clamping force curve 04 and the second clamping force curve 05, at time point t1, a clamping force already exists between the brake pads and the brake disc or brake drum. This state occurs, for example, when the parking brake is operated or activated, if the user or driver is still operating the brake pedal of the service brake.

[0030] The first clamping force curve 04 shows the clamping force being increased to the preset clamping force 07 as quickly as possible. Even when... Figure 1When not shown, the locking mechanism 12 may be activated at time point t3 when the maximum value or preset clamping force 07 is reached. In this case, the drive mechanism is completely disabled for a very short time after the clamping force decreases again and the locking mechanism assumes the holding of the clamping force. Therefore, energy-optimized activation of the parking brake can be achieved even when the fixed time period t10-t1 has not expired or been exhausted after activation.

[0031] The second clamping force curve 05 illustrates an alternative design for activating the parking brake. In the second clamping force curve 05, the clamping force is increased with optimized load, while avoiding high acceleration on the drive mechanism side. The rotational speed of the drive mechanism is increased slowly until the rated clamping force or the preset clamping force 07 is reached.

[0032] In the third clamping force curve 06, similar to the first clamping force curve 04, but starting from the "fully open" electromechanical brake / service brake, the clamping force increases rapidly and energy-optimized until the preset clamping force 07 is reached at time point t4.

[0033] Curve 08, showing the activation of the locking mechanism, indicates that... Figure 1 In the example, the locking mechanism 12 is activated at time point t4, and thus the brake pad is preferably initialized by the pawl engaging the ratchet in the holding position. As mentioned above, regarding the first clamping force curve 04, this activation can also occur at time point t3 in the locking mechanism activation curve 08.

[0034] Between time points t4 and t8, the clamping force 13 on the drive mechanism side is eliminated, particularly gradually reduced. This reduction in clamping force is advantageously achieved by reducing or eliminating the motor torque of the drive mechanism. After an equilibrium is reached between the locking mechanism and the clamping mating parts (i.e., brake pads and brake discs or brake pads and brake drums), for example, at time point t9, a sensor can detect whether there is still movement on the drive mechanism side or whether the drive mechanism is stationary. This allows for the examination of the drive mechanism's motion state.

[0035] At time point t10 (which is fixed as the distance from time point t1 and is unchangeable or constant as the time period t10-t1), output unit 01 is activated according to the function curve of output unit 02, and thus outputs the operation of the parking brake or output operation confirmation 14 to the user.

[0036] With the help of Figure 1It can be seen that there are different possibilities to change the clamping force curves 04, 05, and 06 within the fixed time period t10-t1, while simultaneously ensuring that at time point t10, after the parking brake is activated, a reliable operational confirmation can be output. In particular, the initial state (which is shown at time point t1, for example, through different initial points of the first clamping force curve 04 and the third clamping force curve 06) can be taken into account so as to adapt the clamping force by means of specific optimizations, such as load optimization, energy optimization, or otherwise, and thus adapt the clamping force curves accordingly.

[0037] For example, by determining and / or considering the position of the drive mechanism and / or brake pads and / or the level of the supply voltage of the parking brake and / or the temperature of the parking brake, especially the operating temperature of the electromechanical mechanism, the initial state of the clamping force at time point t1 can be determined and / or approximated.

Claims

1. A method for operating an electromechanical parking brake, particularly for motor vehicles, comprising the steps of: - Identify the preferred operation requirements on the user side implemented via the switching unit (11). - A preset clamping force is established via a drive mechanism by moving at least one brake pad relative to the brake disc or brake drum to a holding position (07). - Activate the locking mechanism (12) to secure the brake pad in the holding position, preferably by means of the pawl engaging in the ratchet; - Eliminate, and in particular gradually reduce, the clamping force provided by the drive mechanism (13); - Preferably, the operation confirmation (14) is output to the user via an optical and / or acoustic output unit (01). Its features are, Regardless of the initial state of the electromechanical parking brake, after a fixed time period (t10-t1), the operation confirmation (14) is output according to the operation requirement (11), wherein, at the time of the output, the locking mechanism is activated and / or the clamping force of the drive mechanism is eliminated.

2. The method according to claim 1, characterized in that, Before outputting the operation confirmation (14), the locking mechanism is checked, especially by checking the motion state of the drive mechanism, during the fixed time period (t10-t1).

3. The method according to claim 1 or 2, characterized in that, The establishment of the preset clamping force (07) and / or the activation of the locking mechanism (12) and / or the elimination of the clamping force (13) are performed in an optimized, especially as quickly as possible, manner.

4. The method according to any one of the preceding claims, characterized in that, The establishment of the preset clamping force (07) and / or the activation of the locking mechanism (12) and / or the removal of the load by the clamping force (13) are performed in an optimized manner, especially with full utilization of the available partial range.

5. The method according to any one of the preceding claims, characterized in that, The operation of the drive mechanism and / or the operation of the locking mechanism are determined or optimized based on the initial state of the electromechanical parking brake and taking into account the fixed time period (t10-t1).

6. The method according to any one of the preceding claims, characterized in that, The initial state of the parking brake is determined by determining the position of the drive mechanism and / or the brake pads and / or the level of the power supply voltage of the parking brake and / or the temperature of the parking brake.

7. A controller for controlling an electromechanical parking brake, comprising a connection to a switching unit for a user-side operation request of the parking brake and an optical and / or acoustic output unit (01) for outputting operation confirmation (14) to the user by operating the parking brake, and a connection to at least one sensor device for identifying and / or monitoring the state of the parking brake. Its features are, The controller is designed to activate the parking brake and, after a fixed time period (t10-t1), generate the operation confirmation (14) output according to the operation requirement (11), wherein, when the operation confirmation (14) is output, the locking mechanism is activated and / or the clamping force of the drive mechanism is eliminated.

8. The controller according to claim 7, characterized in that, The controller is designed to perform the method according to any one of claims 1 to 6.

9. An electromechanical parking brake, particularly for motor vehicles, characterized in that, The parking brake has a controller according to claim 7 or 8.

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