Method for operating electric locking actuator, electric locking actuator for parking brake function of motor vehicle, and wheel brake having electric parking brake function

Abstract

The invention relates to a method for operating a locking actuator (34) for a parking brake function, comprising: a ratchet wheel (38); -a parking pawl (46); -a parking pawl actuator (42) for displacing the parking pawl (46) from the reference position in the direction of the ratchet (38) by means of an actuating force; -a reverse spring (54) which urges or pulls the parking pawl (46) in the direction of the reference position, with the following steps:-rotating the ratchet wheel (38) in a first direction of rotation (74) until the parking pawl (46) is free; displacing the parking pawl (46) with a checking force (78) less than the actuating force; checking the rotational degree of freedom of the ratchet (38).

Description

A method for operating an electric locking actuator, an electric locking actuator for use in a vehicle parking brake function, and a wheel brake having an electric parking brake function. Technical Field

[0001] This invention relates to a novel method for operating an electric locking actuator for the parking brake function of a wheel brake, according to the preamble of claim 1. Furthermore, an electric locking actuator for the parking brake function of a wheel brake is also proposed, as well as a novel electrically operable wheel brake for a motor vehicle. Background Technology

[0002] Known electric drive actuators for commercially available electric parking brakes used in wheel brakes are systematically defined as autonomous, and to achieve the electric parking brake function, they are equipped with a separate electric motor actuator (electric motor drive assembly). This electric motor actuator is designed to automatically lock in the absence of current during parking by structural measures and by means of internal friction in the parking brake actuator drive chain. Therefore, in a motor vehicle wheel braking system that combines running brake and electric parking brake (EPB) functions, in addition to the parking brake electric motor drive configured to automatically lock in the absence of current, there is a subordinate running brake actuator whose drive system is defined as being in the released state in the absence of current, without structural self-locking. Here, the running brake actuation system is typically configured as a hydraulic piston cylinder assembly.

[0003] In contrast, DE 196 15 186 C1 proposes a particularly efficient and rationally designed all-electric operable wheel brake, which is a disc brake type with an electric motor drive actuation system for electric running braking and electric parking braking functions, wherein the same drive system of the electric motor drive actuation system is constructed to be electrically inhibited and is used for all braking functions.

[0004] The scheme disclosed in DE 10 2018 109 465 A1 is not integrated into the wheel brakes, and the actuation system lacks brake clamping force generation. Instead, an automatically decelerating motor vehicle drive chain, employing an improved method and including a space-saving installation structure, is proposed for determining the state of a spindle-driven transmission lock. Its locking kinematics are configured such that the transmission lock automatically engages or disengages from the parking lock wheel in a form-locking manner by means of an electric motor, i.e., when the spindle-type parking lock actuator is actuated. To determine the additional state between the engaged and disengaged parking pawls, the axial displacement position of the spindle is sensed and detected here by a measuring coil.

[0005] The scheme in DE 10 2018 118 258 A1 is to some extent consistent with the transmission mechanism locking technology according to DE102018109465 A1, except that, as a replacement for the measuring coil, an axially oriented inner hole is assigned to the spindle drive so that an inductive sensor can be set up in a space-saving manner for sensing detection.

[0006] An electromechanical wheel brake is known from DE 10 2020 213 916 A1, having a brake housing module and an adjustment motor module electrically or electronically driven by a control unit, having a drive and transmission mechanism transmission system, wherein at least one adjustment element is provided, which is designed and set by means of a transmission element to act on at least one associated vehicle friction lining so as to engage in releasable frictional cooperation with a rotatably supported brake rotor.

[0007] Figure 3 of EP 1 032 773 B1 shows an electric parking lock with shape-locking non-electric locking for an electric combination disc brake configuration, wherein the electric disc brake system of this combination suffers from a lack of adequate diagnostic capabilities. Summary of the Invention

[0008] The objective of this invention is to provide an improved method for operating a locking actuator for a parking brake function or for operating a parking lock, which offers enhanced safety. Furthermore, an improved locking actuator for a parking brake function and an improved electrically operable wheel brake are also proposed. Addressing the shortcomings of the prior art, the objective of this invention is to propose a novel and improved method for operating an electrically locking actuator for the electric parking brake function of a wheel brake. Additionally, a novel electrically locking actuator for the parking brake function of a motor vehicle's wheel brake is also desired. A novel electrically combined-operated wheel brake for a motor vehicle with an electric parking brake function is also proposed.

[0009] According to the integrated wheel braking system or parking brake operation method proposed in this invention, which has an electric locking actuator for parking brake function, to activate the electric parking brake, one or more brake pads are pressed against their respective brake rotors (brake drums or brake discs) by an electric motor having a transmission mechanism (actuator) and an adjustment device (preferably a spreading device with a predetermined preset braking clamping force), and the clamping / holding force is locked and held in a form-locking manner in the absence of current. Therefore, when parking, the preset clamping force flow of the friction brake is "self-closed" and also locked in a form-locking manner. In other words, the wheel brake is of the friction brake type, which is to some extent "self-tensioned or pre-tensioned" by the actuator force, and the electric motor or transmission mechanism is locked in a form-locking manner by an electrically switchable, i.e., electrically responsive parking pawl or parking brake pawl, without the need to apply current when parking. By definition, the parking pawl is switchably and form-locked into an actuator drivetrain that exists in the form of a ratchet or gear with barbed teeth. This engagement occurs precisely when the switchable parking pawl of the wheel brake is aligned with the cavity between the two protrusions—that is, the cavity between the two ratchet / gear teeth—provided it is correctly positioned, controlled, or adjusted. This ensures that the holding force is borne by the parking pawl during parking, and that the parking pawl simultaneously remains automatically in the locked position.

[0010] The parking brake is released when the ratchet is moved in the tension direction by the electric motor and the parking pawl is pushed out of its form-locked engagement, i.e., becomes free. For this purpose, a mechanical return mechanism acts on the parking pawl, which preferably has at least one elastic element (e.g., an elastic tension spring and / or compression spring), which can be configured as a counter-spring. Particularly preferred is that the elastic element is provided with a predetermined elastic preload, and with this preload substantially loads or holds the parking pawl in the unoperated released position. Therefore, the (elastically preloaded) counter-spring can be provided and configured to push the parking pawl back to its unoperated initial position when the parking brake is released, as the profile of the ratchet's barbs allows or releases the necessary free space for the pawl's return movement.

[0011] As described above, activating and deactivating the parking brake within the parking operation framework is generally desirable and is achieved satisfactorily in interference-free and trouble-free operation. However, the present invention also includes an important safety measure to avoid interference, in case of malfunction (e.g., due to the breakage of the reverse spring 54), as a countermeasure. This is because, without a safety measure, the spring breakage mentioned in the example could lead to unintended locking of the wheel brakes while the vehicle is in motion. This is especially true during electric motor-controlled running / service braking, where the brake pads are clamped relative to the brake rotor by the electric motor, transmission mechanism, and spreading unit, i.e., spread out, for example, inside the brake drum. Therefore, the present invention also identifies and avoids the dangers posed by defective conditions (unintended locking / locking problems) by means of a special inspection method. This is because, during vehicle operation, each running wheel brake must be indicated as being in a released state without current, and any inhibition of the brake operating mechanism must be eliminated and prevented during vehicle operation (during running / service braking). To reduce the load on the brakes, the electric motor or the expansion unit is retracted, and the brake pads are returned to their unbraked initial position or brake-ready position in a resilient manner via one or more brake pads.

[0012] Especially from a Failure Mode and Effects Analysis (FMEA) perspective, i.e., in the event of a defective return mechanism in the electrically switchable parking pawl (e.g., due to environmental influences, wear, jamming, damage, or fatigue (fracture or missing) of the elastic element / reverse spring), it is conceivable that the parking pawl might engage uncontrollably and automatically in a form-locking manner without requiring a parking brake request from the vehicle driver or an automatically requested electric parking brake operation. Therefore, under certain boundary conditions, such as vibration or shock (which may occur during vehicle use) accompanied by system defects, there is essentially a potential for unintended parking pawl engagement. However, undesirable and additionally form-locking parking brake engagement could fundamentally jeopardize the vehicle's driving safety during operation, which is efficiently, safely, and sustainably eliminated by this invention.

[0013] This invention therefore makes a significant contribution to the electric automation (status) monitoring of electric wheel brakes in passenger vehicles, thereby making a special contribution to improving vehicle driving safety. To this end, through system construction and methods, it avoids certain issues in principle, thus constituting a safety system that ensures safety during vehicle operation. It will not happenRandom or otherwise unexpected parking brake lock-up of wheel brakes can lead to undesirable effects, such as undesirable friction application, undesirable braking torque, undesirable continuous braking, or undesirable wheel lock-up. With this invention, vehicle driving stability is safely established in all situations, and the state of the wheel brakes / parking brakes is safely, electrically, and preferably automatically detected. Information regarding the identified (parking) brake state or the corresponding parking pawl is located in a connected control and / or regulation unit (e.g., EPB + ESC-ECU) and can be configured, respectively, according to their respective (software) configurations, such as for electric automation, particularly driverless vehicle control, further processing supported by EDV, and / or operation via services, thus requiring integration by the vehicle manufacturer, communication, and sharing with third parties as desired.

[0014] Regarding this method, the task is solved according to the present invention by a method having the features of claim 1. The method is for a locking actuator operating a parking brake function, the actuator comprising a ratchet or parking lock wheel, a parking pawl and a parking pawl actuator for actuatingly displacing the parking pawl from a reference position toward the ratchet, and a reverse spring that pushes or pulls the parking pawl toward the reference position. The method includes the following steps: rotating the ratchet in a first rotational direction until the parking pawl is free; displacing the parking pawl using a checking force less than the actuating force; and checking the rotational freedom of the ratchet.

[0015] In summary, this invention presents for the first time a particularly innovative, safe, rationalized (synergistic), and efficient brake-by-wire solution that meets all legal requirements and FMEA specifications for electric combined passenger car wheel brakes (passenger car service brake + integrated parking brake), and can be implemented without a hybrid power supply. This is because only a single electric motor-based actuator is needed to generate the electric braking clamping force for each wheel (for both service and parking brake functions). This actuator defines the same electric motor drive unit (MGU) for all braking functions (service and parking brake functions), and this drive unit is structurally configured to be substantially non-self-locking. In other words, it rationalizes the complex hydraulic braking and the non-electrically self-locking electric parking brake motor drive unit compared to, for example, the currently common hydraulic combined passenger car wheel brakes (drum brakes or disc brakes) with integrated electric parking brakes. According to the present invention, more value is systematically created, previously necessary hardware expenses are reduced, environmental friendliness and sustainability are promoted, and weight savings and rationalization synergies are released incidentally, which are in the best interests of all automotive customers, shareholders and stakeholders.

[0016] The ratchet or parking lock wheel has multiple barbed teeth, with the parking pawl engaging the teeth of the ratchet to perform the parking brake function.

[0017] The state of the ratchet being free means that the parking pawl does not contact or restrict the rotational movement of the ratchet when it is rotating.

[0018] The advantageous features, effects, and designs of the invention are shown in the dependent claims and the description based on the accompanying drawings.

[0019] This invention is based on the consideration that accidental locking of the parking pawl during driving must be absolutely prevented. The integrity of the reverse spring should be guaranteed at every moment during vehicle operation.

[0020] As is now recognized, this can be achieved by checking the remaining spring force. This ensures that the parking pawl will remain in the unlocked position, even under vibration or impact.

[0021] Advantageously, when checking the rotational freedom of the ratchet, the ratchet rotates at least once in a second rotational direction opposite to the first rotational direction. This reliably checks whether the parking pawl is engaged with the ratchet.

[0022] In an advantageous embodiment of the method, the ratchet rotates at least once in both rotational directions.

[0023] The rotation of the ratchet is preferably controlled by torque limiting. The actuator motor torque can be so large that it could potentially press the protruding pawl against the parking lock wheel and cause it to break. This torque limiting ensures the mechanical integrity of the parking pawl and ratchet in the event of a defective reverse spring.

[0024] When the ratchet has free rotation, the power supply to the parking pawl actuator is terminated. The function of the reverse spring has been successfully verified, and the parking brake can continue to operate safely.

[0025] In a preferred embodiment of this method, if the free rotation of the ratchet cannot be determined or verified, it is checked again for rationalization. If the free rotation still cannot be determined or verified, the wheel brake is reported as defective. The vehicle is then driven using only three brakes. The vehicle manufacturer or customer preferably decides on the next steps.

[0026] In a preferred embodiment, the height of the inspection force is equivalent to the force required to guarantee the vibration. The resulting force is equivalent to the mechanical impact of the maximum defined vibration requirement. Preferably, this is equivalent to a 50g impact in the parking pawl actuation direction. The spring force should be greater than this force in all cases.

[0027] Regarding the locking actuator for the parking brake function, the above-mentioned task is solved according to the present invention by a parking brake function locking actuator having the features of claim 7. This parking brake function locking actuator includes a ratchet, a parking pawl, a parking pawl actuator for power-displacement of the parking pawl from a reference position toward the ratchet, a reverse spring that pushes or pulls the parking pawl toward the reference position, and a control and / or adjustment unit configured to perform the method described above.

[0028] In a preferred embodiment, the parking brake locking actuator is electrically constructed to have at least one coil, which is powered by an actuation current to displace the parking pawl. The actuation current is accordingly chosen to be sufficiently large to apply the desired actuating force to the parking pawl.

[0029] In a further preferred embodiment, the parking brake function locking actuator can be designed according to hydraulic or pneumatic working principles, and hydraulically or pneumatically operate the parking pawl.

[0030] In a preferred embodiment, the reverse spring is a compression spring / pressure spring.

[0031] The parking brake locking actuator preferably has a housing, through which a reverse spring configured as a compression spring is supported on the bottom of the housing. The bottom has an opening through which the parking pawl can be axially displaced.

[0032] Regarding electrically operable wheel brakes, the above-mentioned task is solved according to the present invention by the parking brake function locking actuator described above. The wheel brake can be constructed as a drum brake or a disc brake.

[0033] A particular advantage of this invention is that the reliable parking brake function of an electrically operable wheel brake can be determined by the method described. The function or integrity of the reverse spring can be checked without measuring the inductance of the coil. Under suitable conditions, the movement of the parking pawl can be detected by measuring the inductance in the coil. However, this is very complex in terms of development and implementation.

[0034] The proposed, more economical solution prevents unintended brake lock-up during driving, which could lead to safety-critical driving situations. This method can be applied to various electrically operated wheel brakes with locking actuators for parking brake functions. Attached Figure Description

[0035] Examples of embodiments of the present invention are illustrated with reference to the accompanying drawings. In the drawings, several strongly schematic diagrams are shown: Figure 1 schematically illustrates a preferred embodiment of a drum wheel braking system, in which electric operation and a parking brake are combined, including a parking brake function lock-up actuator; Figure 2 shows a method flowchart in the preferred embodiment; Figure 3 schematically shows the parking brake function lock-up actuator in a first method step; Figure 4 schematically shows the parking brake function lock-up actuator in a second method step; Figure 5 schematically shows the parking brake function lock-up actuator in a third method step; and Figure 6 schematically shows the parking brake function lock-up actuator in a fourth method step. Detailed Implementation

[0036] In the accompanying drawings, the same parts, components or features are indicated by the same reference numerals.

[0037] The combined electric vehicle wheel braking system / wheel brake 2 schematically shown in Figure 1 is a drum brake type, essentially having one, two or more brake shoes or brake pads 6, which are brought into frictional engagement with the allocated brake rotor, particularly to the system of brake drums (not shown), by means of an adjustment unit or a spreading unit 10 to measure or apply a preset force / clamping force to realize a running brake request or a stationary brake request. The locking actuator 38 for parking brake function according to the invention is therefore also applicable to wheel braking systems defining one or more brake discs (not shown). Here, the (brake) clamping force or brake load can be sensed by means of a braking force sensor and / or a braking torque sensor (hereinafter referred to as brake load sensor 14) via a control and / or adjustment unit 48. The load, obtained directly or indirectly, or determined as information, is used in the electric control and / or adjustment unit 48 of the wheel brake for tension control and / or adjustment, and for monitoring wheel braking function. The application of this brake load information can therefore essentially relate to both parking brake function and running brake / service brake function.

[0038] The electrically operable wheel brake 2 has an electric motor 18 for generating the motor clamping force. The electric motor 18 drives a motor shaft 26, which is coupled to the expansion unit 10 via a transmission mechanism 30. Motor position sensors 22 (referred to as MOPS) with a preferably redundant design are used for motor monitoring, control, and / or regulation. In the context of this invention, the concept of motor position can simultaneously refer to the current motor speed, the rotational position of the motor shaft, and the number of rotations of the motor shaft performed from the reference position in one or another rotational direction 74, 90.

[0039] The electrically operable wheel brake 2 further includes a locking actuator for the parking brake function 38. At least one electrically operated switching module or the entire locking actuator may exist as a separately represented sub-component within its own housing 62. The locking actuator for the parking brake function 38 includes, on one hand, a substantially co-rotatable ratchet 38, which may be connected to the motor shaft 26 in a non-rotatable manner, or elsewhere in or within the transmission mechanism. It is substantially sufficient if the ratchet 38 is present on the transmission shaft as a subsequent transmission mechanism component, and the transmission shaft participates in the transmission power flow of the actuation system via at least one engaging transmission mechanism.

[0040] Furthermore, the locking actuator of the parking brake function 38 includes a parking pawl actuator 42 for the parking pawl 46. In a preferred illustrated embodiment, the parking pawl 46 is rotatably fixed in a bearing within the wheel brake housing, anchor, or bracket. Here, the parking pawl 46 is translationally movable relative to the wheel brake. Thus, the illustrated parking pawl actuator has a switching position for laterally movable, as needed, the parking pawl 46 from a rear reference position to a forward extended engagement position, in which the parking pawl 46 engages the ratchet 38 and locks it in a manner that prevents relative rotation. For a kinematic alternative design, the unillustrated parking pawl may exist in a relatively oscillating manner relative to the ratchet 38, resulting in a restricted oscillating motion that can be performed for electric switching.

[0041] The parking pawl actuator 42 has at least one electric coil 44 addressed by the control and / or adjustment unit 42, which is used for electric switching, i.e. for the kinematic movement, displacement or oscillation of the parking pawl 46, and is powered by a short current pulse to define a preset actuation current.

[0042] The positional change caused by the current pulse and the parking pawl 46, which is rotatably supported, engage in a form-locking manner with the corresponding cavity of the ratchet 38, thus holding the wheel brake in its clamped position. This is because the electric actuation system is locked to prevent release due to the rotation of the ratchet 38, which in turn causes the actuation system, motor shaft 26, etc., to form-lock without electrical suppression. Therefore, the wheel brake is held in parking brake function by its clamping force in a form-locking manner without current. The tension position of the brake pads 6 and their pressure against the brake rotor / brake drum are thus fixed in a form-locking manner without electrical interference. The parking brake function is thus achieved.

[0043] In such an electrically operable wheel brake 2, it is important that the resistance to the rotation of the ratchet 38 reliably functions, thereby ensuring reliable parking of the vehicle and preventing accidental release of the brake. It is also important that the parking pawl 46 does not accidentally, for example, engage the ratchet 38 while the vehicle is in motion, which would cause the brake to lock. The locking actuator for the parking brake function 34 is equipped with an electrically controlled and / or regulating unit 48, which oversees the wheel brake, particularly its parking brake function, i.e., release and operation, respectively controlled or regulated. For this purpose, the control and / or regulating unit 48 is substantially electrically connected to the sensors, the electric motor 18, the motor position sensor 22, and the parking pawl actuator 42. The electrically controlled and / or regulating unit 48 is further designed, suited, and intended to perform the operating methods explained in detail below.

[0044] According to the method of the invention, an example of its design is described in more detail below in connection with Figures 4-6, further ensuring that the unoperated actuator drive chain and the unoperated parking pawl 46 are always kept in their unlocked position, so that the essentially released brakes are satisfied as the initial prerequisite or requirement of the electric passenger vehicle wheel brakes from the operating braking type.

[0045] In Figure 2, the method is represented in a flowchart in a preferred embodiment. Figure 3 shows a switchable locking actuator 34 for the parking brake function, shown as a component / module within its own housing 62, in a state in which the parking brake is activated. For this purpose, the parking pawl 46 engages the ratchet 38 in a form-locking manner. To make this possible, the electric locking actuator of the parking brake function 34 has a parking pawl actuator 42 and its electromagnetic coil 44, which is powered by a predetermined current greater than or equal to the actuation current for shifting the magnetic anchor of the parking pawl 46 from a reference position to the engagement position shown in Figure 3. The locking actuator of the parking brake function 34 also has at least one return elastic element. The elastic element is substantially arbitrary in construction. For example, the elastic element is constructed as a reverse spring 54 for moving the parking pawl 46 to the reference position when the operated parking brake is released, and substantially maintaining the parking pawl 46 in its reference position (i.e., the released position) when the coil 44 is de-energized. For example, the resilient element is tensioned between the parking pawl 46 and the housing 62 with a defined elastic preload. In a design that functions as a reverse spring 54, the resilient element can, on one hand, sit on the bottom 58 of the housing 62, where an opening 66 can further be designed as an outlet for the parking pawl 46. Ultimately, it can be understood that the resilient element, on the other hand, sits within, on, or on the seat of the parking pawl 46.

[0046] The method explained below is preferably performed during the release of the parking brake. For example, the vehicle is parked and the driver desires, preferably automatically, to proceed.

[0047] In the first method step 70 (see Figure 2), as shown in Figure 4, the ratchet 38 is electrically rotated in the first rotation direction 74 via an electric control and / or adjustment unit 48 until the parking pawl 46, without its form-locking barb, is laterally free and not engaged with the ratchet 38, automatically disengaging from its form-locking-rotational fixed engagement with the ratchet 38. This example is based on a spring-loaded elastic element that substantially permanently loads the parking pawl with a defined preload force, and the line of action of the spring preload force always points in the release direction. Therefore, the permanent spring force / preload of the elastic element serves as a return mechanism. In parallel or simultaneously with this, the parking pawl actuator 42 is powered with a current less than the actuation current. The actuating current is a current that energizes coil 44, the magnitude of which is set such that the electromagnetic actuating force applied by parking pawl actuator 42 is sufficient to overcome the predetermined preload applied by the elastic element, i.e., to cause parking pawl 46 to shift in the engagement direction under the electromagnetically applied force, thereby engaging with ratchet 38 in a form-fit manner. It is understood that the electric control and / or regulating unit 48 observes and / or monitors different applied electric currents (electric motor, coil, etc.). This thus enables the functional and / or position sensing of parking pawl 46. Regarding electric motor 18, monitoring of motor current may also be present, which may further include monitoring due to the rotation direction switching to the first or second polarity.

[0048] During a small (check) power supply, two opposing, competing forces act on the parking pawl 46: 1. an electromagnetic check force 78 generated by the relatively small energization of the parking pawl actuator 42, and 2. a spring force 82 acting in opposite directions on the parking pawl 46 by the elastic element / reverse spring 54. Since the check current (which is related to the check force 78) is set to be less than the actuation current, the parking pawl 46 should not move toward the engagement direction of the ratchet 38 when the reverse spring 54 is present and properly preloaded. Only in the event of a malfunction, such as poor movement of the pawl actuator, complete absence of the elastic element, breakage of the elastic element, wear or jamming of the elastic element, or a malfunction with similar symptoms (resulting in insufficient holding force applied by the elastic element / reverse spring 54), may the parking pawl 46 shift toward the engagement direction of the ratchet 38 or be in an undesirable form-fit engagement state during the energization of the parking pawl actuator 42.

[0049] It has been recognized that the driving force required to move the parking pawl 46 from its stationary state is greater than the driving force sufficient to allow the moving parking pawl 46 to continue its uniform movement after static friction has been overcome (the difference between static and dynamic friction should be considered as an improvement). Therefore, it is suggested that the so-called "release force" be considered. Furthermore, it should be noted that the above-mentioned phenomena and stick-slip effects can be automatically detected by further improved control and regulation, i.e., by automatic detection, for example, in conjunction with a correspondingly further improved electronic control and / or regulation unit 48, thereby automatically identifying and learning interference effects or hindrances during the process and storing them in a microprocessor / memory, so that the corresponding interferences can be automatically filtered out or compensated for in future repeated actuation processes without departing from the invention.

[0050] In the second method step 86, shown in Figure 5, the uninterrupted rotational freedom of the ratchet 38 is checked or tested (verified) to verify the parking pawl function. Thus, an operational method for automatically electrical or electronic verification of the proper functioning of the parking brake is defined. The coil 44 of the parking pawl actuator 42 checks the current supply via a control and / or regulating unit 48. The electric motor 18 is powered in reverse via the control and / or regulating unit 48, causing the ratchet 38 to rotate in a second rotation direction 90, precisely opposite to the first rotation direction 74 defined. Automated I / O control via the electric control and / or regulating unit 48 occurs as follows: the spring force F_spring applied to the parking pawl 46 with a fully elastically preloaded elastic element / reverse spring 54—as can be seen—is always greater than the force F_coil generated by checking the current, resulting in the parking pawl 46 shifting little or no noticeably toward the ratchet 38. Because the parking pawl 46 moves toward the ratchet 38 with little or no impact, no inhibition by shape closure occurs, so the wheel brake can be released and the ratchet 38 can rotate freely and unimpeded in the second direction 90.

[0051] With the help of the motor position sensor 22 (referred to as MOPS), the rotation of the ratchet 38 is monitored and captured by the motor control system implemented in the control and / or adjustment unit 48, so that the motor automatically verifies whether it has rotated freely.

[0052] In step 94 of the third method shown in Figure 6, if the rotational freedom of the ratchet 38 is determined, the actuation current is reduced to zero.

[0053] According to the invention, preferably, the method according to the invention and the electric locking actuator according to the invention are present in light passenger vehicles for electric parking brake applications, or preferably in motor vehicle drum brakes. Here, virtually any type of drum brake can be used, such as, in particular, a single-acting drum brake, but a servo drum brake, especially a dual-servo drum brake, is particularly preferred. Alternatively, the invention can be present in motor vehicle disc brakes. Here, caliper disc brakes with or without hammer-shaped friction pads are primarily provided, as are proven pin-slip disc brake types.

[0054] In particular, for heavy and medium-sized passenger vehicle applications, such as SUVs, flatbed trucks, vans, motorhomes or similar applications, an alternative solution can be provided if the present invention exists in the form of a centrally integrated "drum-in-hat" automotive drum brake combined with an automotive disc brake as the operating brake.

[0055] List of reference numerals

[0056] 2. Electrically operated wheel brakes

[0057] 6 Brake pads 10 support unit

[0058] 14 Braking force / braking load sensor

[0059] 18 Electric motors

[0060] 22 Motor position sensor

[0061] 26 motor shafts

[0062] 30 Transmission Mechanism

[0063] 34 Locking actuator for parking brake function

[0064] 38. Ratchet

[0065] 42 Parking Pad Actuator

[0066] 44 coils

[0067] 46 Parking Pad

[0068] 48 Control and / or regulation unit

[0069] 50 Methods and Steps

[0070] 54 Reverse Spring

[0071] 58 Bottom

[0072] 62. Shell

[0073] 66 Opening

[0074] 70 Methods and Steps

[0075] 74 First direction of rotation

[0076] 78. Inspection capacity

[0077] 82 Spring force

[0078] 86 Methods and Steps

[0079] 90 Second rotation direction

[0080] 94 Third Method Steps

Claims

1. A method for operating an electric locking actuator (34) for a parking brake function, the electric locking actuator comprising: - a ratchet (38); - a parking pawl (46); - a parking pawl actuator (42) that uses an actuating force to displace the parking pawl (46) from a reference position toward the ratchet (38); - an elastic element, particularly a reverse spring (54), which pushes or pulls the parking pawl (46) toward the reference position; and a control and / or adjustment unit (48) having electronic components, characterized in that: The process includes the following steps: - rotating the ratchet (38) in the first rotation direction (74) until the parking pawl (46) is free; - displacing the parking pawl (46) using a check force (78) less than the actuation force; - checking the rotational freedom of the ratchet (38).

2. The method according to claim 1, characterized in that, When checking the rotational degree of freedom of the ratchet (38), the ratchet (38) is rotated at least once in a second rotational direction (90) opposite to the first rotational direction (74).

3. The method according to claim 1 or 2, characterized in that, The ratchet (38) is rotated in a torque-limited manner.

4. The method according to one or more of the preceding claims, characterized in that, With the rotational degree of freedom of the ratchet (38) present, the actuation of the parking pawl actuator (42) is terminated.

5. The method according to one or more of the preceding claims, characterized in that, The magnitude of the inspection force is equivalent to the vibration requirement to be guaranteed.

6. The method according to one or more of claims 1-5, characterized in that, The method is configured to perform a software-supported, and particularly automated, and especially self-executing, functional check on the correct function of the electric parking brake for use with either a preferred electric motor vehicle drum brake or a preferred electric motor vehicle disc brake.

7. A locking actuator (34) for a parking brake function, comprising: - a ratchet (38); - a parking pawl (46); - a parking pawl actuator (42) which uses an actuating force to move the parking pawl (46) from a reference position toward the ratchet (38); - an elastic element, particularly a reverse spring (54), which pushes or pulls the parking pawl (46) toward the reference position; and - an electronic control and / or adjustment unit (48).

8. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The electronic control and / or regulation unit (48) is designed and configured to perform the operating method according to any one of claims 1-5.

9. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The parking pawl actuator (42) is electrically connected to the control and / or regulation unit (48) and is configured with at least one coil (44) which is powered by the control and / or regulation unit (48) with an actuation current to displace the parking pawl (46).

10. The locking actuator (34) for parking brake function according to one or more of claims 1-9, characterized in that, The elastic element exists in the form of a specified preload, so that the parking pawl (46) is continuously loaded with preload through the elastic element.

11. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The elastic element is constructed as a compression spring.

12. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The parking pawl actuator (42) exists as a separately formed sub-component within its own housing (62).

13. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The elastic element is elastically tensioned between the bottom (58) of the housing (62) and the parking pawl.

14. The locking actuator (34) for parking brake function according to one or more of the preceding claims, characterized in that, The parking pawl actuator (42) is integrated on or in the motor drive mechanism assembly (MGU) of the electric brake actuator of the wheel brake (2).

15. A wheel brake (2) comprising a locking actuator (34) for parking braking function according to one or more of the preceding claims 7-14.

16. The wheel brake (2) according to claim 15, characterized in that, The wheel brake (2) is constructed as a motor vehicle drum brake.

17. The wheel brake (2) according to claim 15, characterized in that, The wheel brake (2) is configured as a motor vehicle disc brake.

18. The wheel brake (2) according to one or more of claims 15-17, characterized in that, The wheel brake (2) is constructed as an integrated drum brake for electric parking braking, combined with a disc brake for service.

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