Improvements to the operation of electromechanical parking brakes, especially for use in automobiles.

Abstract

In particular, it enables the improvement of the operation of an electromechanical parking brake. [Solution] A method for operating an electromechanical parking brake, comprising: a method step of detecting an operation request 11 from a user side; a method step of generating a predetermined clamping force 07 by displacing at least one brake lining to a holding position relative to a brake disc or a brake drum via a drive mechanism; a method step 12 of actuating a ratchet mechanism to lock the brake lining in the holding position; and a method step 13 of releasing, in particular gradually reducing, the clamping force supplied by the drive mechanism.

Description

Technical Field

[0001] The present invention relates to a method for operating an electromechanical parking brake, which is particularly intended for use in motor vehicles. Furthermore, the present invention relates to a controller for controlling the electromechanical parking brake. The present invention also relates to an electromechanical parking brake.

Background Art

[0002] Electromechanical brake systems (EMB) for use in motor vehicles are known. In this case, an electric drive mechanism, for example in the form of an electronically commutated motor (EC machine), moves or displaces the brake lining in the direction of the brake disc or brake drum via a speed reduction device and via a rotation-to-translation transmission device such as a ball screw transmission (KGT), thereby generating friction, which in turn generates braking force or deceleration. Conversely, the brake lining can be moved or displaced away from the brake disc or brake drum to reduce or eliminate the friction and to reduce or eliminate the deceleration caused by the friction. In this way, the vehicle can generate or release braking force as required by the driver under the control of the electric drive mechanism.

[0003] Furthermore, it is known that electromechanical brake systems are designed to minimize or eliminate self-locking. The objective is to ensure that, in the event of a failure in the electrical mechanism, the corresponding brake releases the braked wheel again, allowing the vehicle to continue moving, and, in some cases, outputs a corresponding driver or user warning regarding the malfunction or failure of the electromechanical brake. In addition, it is already known from the prior art that electromechanical brake devices can be used as parking brakes or handbrakes. Since the parking brake or handbrake function must be performed or maintained without energy, the prior art involves setting a target clamping force between the brake lining and the brake disc / brake drum via the electromechanical brake device, and then locking the mechanical action path from the electric drive mechanism to the clamping partner, i.e., the mechanical action path to the brake lining and brake disc / brake drum. This lock can be achieved on a friction basis or by shape-constrained fitting.

[0004] In this regard, Patent Document 1 is known from the prior art. Patent Document 1 describes a method for operating an electric parking brake, in which an unlocked pulse generator is used to output control commands for applying or releasing the handbrake, for example, using a push button. The execution of the command, the status of the handbrake, and / or the normal or malfunctioning function of the system are fed back and signaled using an electrically operable, for example, bistable indicator element that remains in a switching position at any given time without energy consumption.

[0005] In electromechanical braking systems, the electromechanical drive mechanism is typically used for both the service brake and the parking brake. This results in significant variation in the starting position of the brake lining relative to the brake disc or brake drum when a user requests to operate or engage the parking brake. This can lead to the brake lining being statically set to operate or engage the electromechanical parking brake, potentially causing excessive load or energy consumption on involved components such as the drive mechanism, and even resulting in the parking brake being operated or engaged at different speeds. This can cause significant differences in the operating or engagement speed of the parking brake, leading to anxiety for the user or operator, and can also cause unnecessary and excessive wear on the components and parts of the electromechanical parking brake. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] German Patent Application Publication No. 19854105 [Overview of the project] [Problems that the invention aims to solve]

[0007] Against this backdrop, the objective of the present invention is to overcome the shortcomings of the prior art and, in particular, to enable improvements in the operation of electromechanical parking brakes. [Means for solving the problem]

[0008] The method for operating an electromechanical parking brake according to the present invention makes it possible to dynamically configure the operation, meaning that instead of setting individual steps for performing the operation or the operation itself, a time interval is set, which is the time or duration during which the operation must be completed and feedback output to the user must be output. This makes it possible to optimize the actual operation or performance of the electromechanical parking brake within the time interval available between the operation request and the output of the operation confirmation, in a resource-saving or material-friendly manner. Furthermore, the user always receives the operation confirmation output after the user's operation request and after a fixed time interval, resulting in the special advantage that the user gains considerable confidence that the braking action of the electromechanical parking brake has been established safely and reliably.

[0009] Furthermore, the method according to the present invention for operating an electromechanical parking brake, particularly for use in automobiles, includes the following steps, although these steps are not necessarily performed in the order listed below.

[0010] The step of detecting a user's request to operate the electromechanical parking brake via the shift unit.

[0011] The operation of the shift unit can be understood, for example, as the operation of the driving mode to "P" on the driving mode selection unit. The request to operate the electromechanical parking brake may be triggered by other user actions that do not directly presuppose the operation of the shift unit for the parking brake, instead of the operation of the shift unit. For example, the request can be triggered by the driver unbuckling their seatbelt, opening the driver's door, or leaving the driver's seat. Furthermore, within the scope of the automatic parking or exit process, the request can be automatically generated after the final parking position has been reached.

[0012] The steps include: generating a predetermined clamping force by displacing at least one brake lining to a retaining position relative to a brake disc or brake drum, preferably via an electromechanical drive mechanism; acting the ratchet mechanism to lock the brake lining in the retaining position by engaging the ratchet pawl with the pawl wheel; releasing, in particular gradually reducing, the clamping force supplied by the drive mechanism; releasing the clamping force supplied by the drive mechanism, preferably by releasing or reducing the motor torque of the drive mechanism; and outputting operational confirmation to the user, preferably via an optical and / or acoustic output unit.

[0013] In this case, according to the present invention, regardless of the starting state of the electromechanical parking brake, an operation confirmation output is generated after a fixed time interval following an operation request. In this case, it is assumed that at the time of output, or at the moment of output, the ratchet mechanism is in the operating state and / or the tightening force of the drive mechanism is released. This is particularly advantageous because it not only provides a constant, especially a consistently rapid, response to the user regarding the successful operation or activation of the parking brake, but also allows for the optimization, or at least adjustment, of each step of the operation depending on the starting state of the electromechanical parking brake.

[0014] In a first advantageous embodiment of this method, it may be considered to inspect the ratchet mechanism by inspecting the motion state of the drive mechanism in particular, within a fixed time interval and before outputting the operation confirmation. As already mentioned in the preamble above, a suitable electric motor may be used as the drive mechanism. If the ratchet mechanism is operating, and therefore the electromechanical parking brake is operated, an equilibrium state will be generated by the drive mechanism when the tightening force decreases or thereafter. Simultaneously with reaching the equilibrium state, no further movement should be applied to the drive mechanism. This makes it possible to reliably assess whether the parking brake has been operated correctly and whether the ratchet mechanism is operating, that is, through the motion state of the drive mechanism.

[0015] The motion of the drive mechanism can be identified, for example, by evaluating the voltage and current conditions in the corresponding motor. Additional or alternative sensor devices may be provided to detect and inspect the motion state of the drive mechanism.

[0016] A further advantageous embodiment of this method may consider energetically optimizing the generation of a predetermined tightening force and / or the operation of the ratchet mechanism, and especially as quickly as possible. Once the ratchet mechanism is operating and the tightening force from the drive mechanism is completely released, the motor drive is no longer controlled, and therefore no current or electrical energy is required. For this reason, in order to energetically optimize the operation of an electromechanical parking brake, it may be particularly advantageous to generate the predetermined tightening force, operate the ratchet mechanism, and optionally release or reduce the tightening force as quickly as possible. In this way, if the tightening force is already partially or completely applied in the starting position (for example, when the parking brake is operated while the service brake pedal is being operated), the generation of the predetermined tightening force, the operation of the ratchet mechanism, and the subsequent release of the tightening force may be completed well before the fixed time interval ends. In this example, according to the present invention, the operation confirmation is output only after the fixed time interval has expired, so that even if the output is made excessively quickly or prematurely, the user will not be made to feel anxious about the successful operation.

[0017] Conversely, the fixed time interval may be set or defined as follows: even in the starting state, the ratchet mechanism may be activated to generate a tightening force from a state where the electromechanical brake is completely released, and in some cases, the tightening force may be released again before an operation confirmation is output. In this case, other influencing factors such as the operating temperature and / or voltage level of the electromechanical parking brake may also be taken into consideration to ensure reliable and consistent operation within the fixed time interval in any case.

[0018] In further, equally advantageous embodiments, consideration may be given to optimizing the generation of a predetermined tightening force and / or the operation of the ratchet mechanism in terms of load, particularly by making full use of the available fixed time intervals. This is advantageous because it allows the operation or control of the parking brake to be carried out in such a way that all available time intervals or individual partial intervals are made full use of, taking into account the ever-present starting state of the electromechanical parking brake. This avoids high loads on the drive mechanism side, particularly on the electric motor side. Correspondingly, the rotational speed can be increased slowly and then decreased slowly again after reaching the predetermined tightening force. Furthermore, this achieves the avoidance of high acceleration on the ratchet mechanism side. Correspondingly, the current required to operate the ratchet mechanism can be adjusted so that the moving parts of the ratchet mechanism do not strike the mechanical end stopper.

[0019] Further, particularly advantageous embodiments of the present method, as already suggested above, may be intended to specify or optimize the control of the drive mechanism and / or the ratchet mechanism depending on the starting state of the electromechanical parking brake and taking into account the time interval. For example, if it is necessary to fully utilize the entire available fixed time interval, the starting state may be detected and, depending on this starting state, the control of the drive mechanism and the ratchet mechanism for generating and releasing the tightening force may be optimized, for example, energetically and load-wise.

[0020] Similarly, as previously suggested, an advantageous embodiment of the present method may be determining the starting state of the parking brake by determining the position of the drive mechanism and / or at least one brake lining, and / or the level of the supply voltage to the parking brake, and / or the temperature of the parking brake. With respect to the temperature of the parking brake, it is particularly advantageous to sense the operating temperature of the electronic mechanism.

[0021] The above guidelines are particularly well suited to detecting, or at least roughly understanding, the starting state, whether based on the statically given conditions of the electromechanical parking brake or its dynamically variable characteristics. Therefore, based on the detection and evaluation of such characteristics and measurements of the starting state, the operation of the parking brake and the individual method steps can be particularly advantageously optimized or adjusted, while still ensuring that the operation is completed and an operation confirmation output can be provided at the end of the fixed time interval.

[0022] The present invention also relates to a controller for controlling an electromechanical parking brake, namely a controller comprising: a connection to a shift unit for user requests to operate the parking brake; a connection to an optical and / or acoustic output unit for outputting an operation confirmation regarding the operation of the parking brake to the user; and at least one connection to a sensor means for recognizing and / or monitoring the state of the parking brake. According to the present invention, the controller is installed to activate the parking brake and generate the operation confirmation output after a fixed time interval following the operation request, in which case it is assumed that the ratchet mechanism is in the activated state and / or the tightening force of the drive mechanism is released at the time of the operation confirmation output. What is achieved through the controller according to the present invention is, on the one hand, that the parking brake is guaranteed to be in the activated or operated state, and on the other hand, that an operation confirmation is output after a fixed time or fixed time interval in a way that is reliable and understandable to the user.

[0023] This is particularly advantageous because it allows for optimization to be performed while adhering to or maintaining a fixed time interval, depending on the parking brake's release state.

[0024] In an advantageous embodiment of the controller, it may be provided that the controller is configured to carry out the method according to one of the previously described embodiments thereof.

[0025] The present invention also particularly encompasses an electromechanical parking brake for use in a motor vehicle, in which case the electromechanical parking brake comprises a controller according to one of the previously described embodiments thereof. As already mentioned above, the parking brake according to the present invention generates and outputs a constant response in the form of an operation confirmation, which is particularly advantageous for the user, and at the same time provides the possibility of carrying out the actuation of the parking brake in an optimized manner, in particular as a function of the starting state.

[0026] Further advantages, features and details of the present invention will become apparent from the following description of advantageous embodiments of the present invention and the drawings. Brief Description of the Drawings

[0027] [Figure 1] FIG. 7 is a diagram showing a time profile for actuating an electromechanical parking brake according to different embodiments. Modes for Carrying Out the Invention

[0028] In the figures, identical components or components with identical functions are provided with identical reference numerals.

[0029] FIG. 1 is a temporally resolved flowchart for the operation or actuation of an electromechanical parking brake. The time axis 10 shows the respectively prevailing states, characteristics and method steps at a certain point in time. At time t1, the optical output unit 01, which is illustrated by the general parking brake symbol, is not active, i.e. it is not powered on or its backlight is not illuminated. The first functional profile represents the state of the output unit 01 or the functional profile of the output unit in the time interval between time t1 and time t10.

[0030] By activating the optical output unit 01 or illuminating its backlight, an operation confirmation can be output to the user at a fixed time t10. This sets a fixed time interval t10-t1, during which the parking brake is activated and the operation confirmation is output. In the time chart of Figure 1, the functional transition 03 of the user's request to operate the electromechanical parking brake, shown in the lowest signal sequence, is observed to show that at time t1, the operation request 11 is made via the shift unit, which is not shown in detail. Similarly, Figure 1 shows the first tightening force transition 04, the second tightening force transition 05, and the third tightening force transition 06. In the first tightening force transition 04 and the second tightening force transition 05, a tightening force already exists between the brake lining and the brake disc or brake drum at time t1. This condition occurs, for example, when operating or activating the parking brake, if the user or driver also operates the brake pedal of the service brake.

[0031] The first tightening force transition 04 shows that the tightening force increases as quickly as possible to a predetermined tightening force 07. Even if not shown in Figure 1, the ratchet mechanism may already be activated 12 at point t3, for example, when the maximum value or the predetermined tightening force 07 is achieved. In this example, the tightening force decreases again, and after the ratchet mechanism takes over maintaining the tightening force, the drive mechanism becomes completely inactive within a short time. Therefore, even if the fixed time interval t10-t1 has not yet expired or has not been consumed after the operation is completed, energetically optimized operation of the parking brake is possible.

[0032] The second tightening force transition 05 shows an alternative configuration for activating the parking brake. In the second tightening force transition 05, the tightening force increases in an optimized manner under load, and high acceleration on the drive mechanism side is avoided. The rotational speed of the drive mechanism increases slowly until it reaches the target tightening force or a predetermined tightening force 07.

[0033] In the third tightening force transition 06, although it corresponds to the first tightening force transition 04, the tightening force increases rapidly and energetically, optimizing itself, starting from a "fully released" electromechanical brake / service brake, and reaches a predetermined tightening force 07 at time t4.

[0034] The transition 08 of the ratchet mechanism operation, in the example of Figure 1, shows that the ratchet mechanism is activated 12 at time t4, which advantageously engages the ratchet pawl with the pawl wheel, thereby initiating the locking of the brake lining in the holding position. As already mentioned above, this operation in the transition 08 of the ratchet mechanism operation may also be performed at time t3 with respect to the first tightening force transition 04.

[0035] Between time points t4 and t8, the clamping force on the drive mechanism is released, in particular, gradually reduced. The reduction in clamping force is advantageously achieved by reducing or releasing the motor torque of the drive mechanism. After equilibrium is achieved between the ratchet mechanism and its clamping partners, the brake lining and brake disc, or between the brake lining and brake drum, a sensor may be used to detect, for example, at time point t9, whether motion is still occurring on the drive mechanism side or whether the drive mechanism is not moving. This allows for inspection of the motion state of the drive mechanism.

[0036] At time t10, which is fixed as an interval from time t1 and is unchanging or constant as a time interval t10-t1, according to the function transition 02 of the output unit, the output unit 01 is activated, and therefore the operation of the parking brake is output to the user, or an operation confirmation is output 14.

[0037] As shown in Figure 1, it is recognized that there are various possibilities for changing the tightening force transitions 04, 05, and 06 over a fixed time interval t10-t1, while simultaneously ensuring that an operation confirmation can be reliably output at time t10 after the parking brake is activated. In particular, to adjust the tightening force optimally by optimizing it based on specific optimizations, such as load optimization, energy optimization, or other optimizations, and thereby adjust the tightening force transitions, the starting states illustrated as an example, with different starting points for the first tightening force transition 04 and the third tightening force transition 06 at time t1, may be considered.

[0038] The starting state of the clamping force at time t1 can be determined and / or approximated, for example, by determining and / or considering the position of the drive mechanism and / or brake lining, and / or the level of the supply voltage of the parking brake, and / or the temperature of the parking brake, in particular the operating temperature of the electronic mechanism. [Explanation of symbols]

[0039] 01 Output Unit 07 Prescribed tightening force 11 Operation request 12 Ratchet mechanism 13. Releasing the tightening force 14. Output of operation confirmation t10-t1 Fixed time interval

Claims

1. A method for operating an electromechanical parking brake, particularly for use in automobiles, comprising the following steps: - A method step for detecting a user's operation request (11) via a shift unit, - A method step of generating a predetermined clamping force (07) by displacing at least one brake lining to a holding position relative to a brake disc or brake drum via a drive mechanism, - A method step (12) in which the ratchet mechanism is activated to lock the brake lining in the holding position by engaging the ratchet pawl with the ratchet wheel, - A method step of releasing the tightening force supplied by the drive mechanism, particularly by gradually reducing it (13), - A method step of outputting operation confirmation to the user (14) via an optical and / or acoustic output unit (01), In a method that includes, Regardless of the starting state of the electromechanical parking brake, the operation confirmation output (14) is made after a fixed time interval (t10-t1) following the operation request (11), and at the time of output, the ratchet mechanism is in operation and / or the tightening force of the drive mechanism is released. A method characterized by the following:

2. The method according to claim 1, characterized in that the ratchet mechanism is inspected by inspecting the motion state of the drive mechanism in particular within the fixed time interval (t10-t1) and before the output of the operation confirmation (14).

3. The method according to claim 1 or 2, characterized in that the generation of the predetermined tightening force (07) and / or the operation of the ratchet mechanism (12) and / or the release of the tightening force (13) are performed energetically and particularly as quickly as possible.

4. The method according to any one of claims 1 to 3, characterized in that the generation of the predetermined tightening force (07) and / or the operation of the ratchet mechanism (12) and / or the release of the tightening force (13) are performed in a load-optimized manner, in particular by making full use of the available partial intervals.

5. The method according to any one of claims 1 to 4, characterized in that the control of the drive mechanism and / or the control of the ratchet mechanism is specified or optimized depending on the starting state of the electromechanical parking brake and taking into consideration the fixed time interval (t10-t1).

6. The method according to any one of claims 1 to 5, characterized in that the starting state of the parking brake is determined by determining the position of the drive mechanism and / or the brake lining, and / or the level of the supply voltage to the parking brake, and / or the temperature of the parking brake.

7. A controller for controlling an electromechanical parking brake, It includes a connection to a shift unit for user-side operation requests for the parking brake, a connection to an optical and / or acoustic output unit (01) for outputting operation confirmation regarding the operation of the parking brake to the user (14), and at least one connection to a sensor means for recognizing and / or monitoring the state of the parking brake. In the aforementioned controller, The controller is installed to activate the parking brake and generate the operation confirmation output (14) after a fixed time interval (t10-t1) following the operation request (11). At the time of the operation confirmation output (14), the ratchet mechanism is in operation and / or the tightening force of the drive mechanism is released. A controller characterized by the following features.

8. The controller according to claim 7, characterized in that the controller is installed for carrying out the method described in any one of claims 1 to 6.

9. In particular, in electromechanical parking brakes used in automobiles, An electromechanical parking brake characterized in that the parking brake has the controller described in claim 7 or 8.

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