LOCKING MECHANISM, ELECTRIC MOTOR DRIVE UNIT, VEHICLE AND METHOD FOR LOCKING A SHAFT OF A DRIVETRAIN

Description

[0001] The invention relates to a locking mechanism, an electric motor drive unit, a vehicle and a method for locking a shaft of a drive train.

[0002] A locking mechanism between a locking actuator and a lockable shaft of a drive train is known from the publications CN 112922980 A and KR 20190074644 A.

[0003] One of the problems underlying the invention is to provide an improved locking mechanism, particularly for a vehicle.

[0004] This problem is solved by a locking mechanism proposed and protected according to claim 1.

[0005] A locking mechanism, particularly for a vehicle or a vehicle parking lock, is proposed between a locking actuator and a lockable shaft of a drive train.

[0006] A positive locking element is proposed which can be electrically actuated in an axial stroke movement and along the shaft, which can be joined at least sectionally to a shaft-side complement within a positive locking area in order to lock the shaft, and which, in a state in contact with the shaft-side complement at its end face, can be pre-tensioned along the shaft by means of at least one elastic force transmission means against the shaft-side complement.

[0007] In this case, the positive locking element can be supported against a housing section of an electric motor drive unit in a locking state of the shaft, in which the positive locking element and the shaft-side complement interlock in the positive locking area of ​​the locking mechanism, and on which the locking actuator can be attached.

[0008] The locking mechanism has a play in the positive locking area and in the circumferential direction of the shaft between the positive locking element and the shaft-side complement, which, in conjunction with the aforementioned preload of the positive locking element against the shaft-side complement, enables the positive locking element to engage with the shaft-side complement or to join the positive locking element with the shaft-side complement.

[0009] The locking actuator has an electric drive with a stator which drives an internal rotor with permanent magnets, the rotor being designed in the form of a threaded nut of a screw drive which, depending on its direction of rotation, can be moved in the longitudinal direction along a threaded spindle with which it interacts.

[0010] The positive locking element is connected to the movement mechanism of the locking actuator, which causes the axial stroke movement, via at least one elastic force transmission means.

[0011] A shaft-side complement is understood to be a shaft-side counterpart to the positive locking element, which is designed or formed in a manner correspondingly complementary to the positive locking element in the positive locking area. This can be a correspondingly shaped section of the shaft itself or a separate, correspondingly shaped element joined to the shaft, which interacts positively with the positive locking element.

[0012] An elastic force transmission means is understood to be a mechanical energy storage device for the elastic preloading of the positive locking element against the shaft-side complement, for example in the form of at least one separate spring or spring element and / or in the form of at least one spring element section integrated into the positive locking element.

[0013] This energy storage device pre-tensions the positive locking element against its shaft-side complement until the shaft assumes a suitable orientation relative to the positive locking element for a positive lock. As soon as such an orientation is achieved, this energy storage device presses the positive locking element into the shaft-side complement to engage it, thus locking the shaft.

[0014] The proposed locking mechanism allows for a compact, space-saving and cost-effective design within a powertrain, especially in a vehicle.

[0015] Furthermore, the proposed locking mechanism can be implemented in an energy-efficient manner, as the aforementioned preload does not require high actuating forces from the actuator. When the positive locking element engages with its shaft-side complement, only the positive locking element itself is moved, and not the drive train component to be locked.

[0016] In In one embodiment, the shaft-side complement is arranged in the region of one end of the shaft. The locking actuator can be mounted at the end of the shaft and opposite it on the housing section.

[0017] In In another embodiment, the positive locking element is also arranged coaxially to the shaft. This enables a particularly compact design of an electric motor drive unit, especially in a vehicle, that incorporates such a locking mechanism.

[0018] The positive locking element can be formed in the shape of a closed, circumferential, ring-shaped element, which can advantageously be arranged coaxially to the lockable shaft.

[0019] The positive locking element has an internal profile which, in the positive locking area, interacts positively with a profile of the shaft-side complement that is complementary to the internal profile.

[0020] Furthermore, the positive locking element has an external profile that is formed to complement a guide section. This guide section can be a section of the locking actuator itself, which is attached to, or can be attached to, or fastened to, the housing section. Alternatively, the guide section can be formed on, integrated into, or can be integrated into the housing section itself. This guide section longitudinally guides the positive locking element for the axial stroke movement along the shaft. Thus, depending on the implementation of this guide section, the positive locking element can be supported either directly or indirectly by the aforementioned housing section.

[0021] InIn another embodiment, the positive locking element can be supported against a housing section of an electric motor housing or a (reduction) gearbox housing. The locking mechanism can advantageously be integrated into the electric motor housing or (reduction) gearbox housing.

[0022] Furthermore, an electric motor drive unit with a locking mechanism of the type described above is proposed (claim 9).

[0023] Furthermore, a vehicle with such an electric motor drive unit or a locking mechanism of the type described above is proposed (claim 10).

[0024] The term "vehicle" refers to any type of vehicle or motor vehicle that is electrically powered, but especially passenger cars and / or commercial vehicles. These are preferably semi-autonomous and especially fully autonomous vehicles.

[0025] Furthermore, a method for locking a shaft of a drive train, in particular of a vehicle, with a locking mechanism of the type described above is proposed (claim 11).

[0026] In this method, the positive locking element is brought into engagement with the shaft-side complement by utilizing the play in motion and up to a maximum rotational speed of the shaft that depends on the play in motion, by moving the positive locking element in a state where its end face rests against the shaft-side complement, longitudinally along the shaft via at least one elastic force transmission means with a definable force against the shaft-side complement.

[0027] Complement and is pre-tensioned until it clicks into place.

[0028] In one version, a wave of the vehicle rolling from a standstill is locked up to a maximum speed of the vehicle that depends on the movement range.

[0029] Only a relatively small force is required from the locking actuator to create the preload. The applied preload force only needs to be sufficient to bring the positive locking element – ​​utilizing the aforementioned play – into positive engagement with the shaft-side complement within a timeframe dependent on the rotational speed of the shaft or vehicle speed.

[0030] In this process, only the positive locking element of the locking actuator is moved, and not the drive shaft to be locked.

[0031] The invention will now be explained in detail with reference to the figures. Further advantageous embodiments of the invention will become apparent from the dependent claims and the subsequent description of preferred embodiments. These are shown, in part schematically: Fig. 1 shows a proposed locking mechanism in a perspective sectional view; Fig. 2 shows the mechanism in Fig. 1 The locking mechanism shown is depicted in a planar sectional view; Fig. 3den in Fig. 1 The locking mechanism shown is shown in a further, planar sectional view; Fig. 4 shows a positive locking area of ​​the proposed locking mechanism; and Fig. 5 shows an electric motor drive unit of a drive train.

[0032] Fig. 1 Figure 1 illustrates a locking mechanism 2 in which a locking actuator 4 interacts with a lockable shaft 6, for example in the form of a hollow shaft of a drive train.

[0033] The locking actuator 4 comprises a positive locking element 8, which can be electrically actuated in an axial stroke movement in the longitudinal direction X - X and along the shaft 6.

[0034] Fig. 2Figure 8 shows this positive locking element in a state in which it is not engaged with the shaft 6. The shaft 6 is therefore not locked.

[0035] Fig. 3 In contrast, this positive locking element 8 is shown in a state operatively connected or joined with the shaft 6, in which the positive locking element 8 and the shaft 6 interlock in a positive locking area FB, i.e. sectionally, so that the shaft 6 is locked.

[0036] The positive locking element 8 is formed as a closed, circumferential, ring-shaped element with a circumferential recess or opening provided for positive locking. Within this recess, radial, inwardly projecting, rib-, tooth-, or claw-like positive locking elements are formed – distributed around its circumference and at regular intervals – which form an internal profile IP of the positive locking element 8 and which can be positively engaged with a shaft-side complement in the positive locking area FB.

[0037] The shaft-side complement is formed in or on the shaft 6 itself in a region of the end of the shaft 6 facing the locking actuator 4, namely in the form of a shaft outer profile 10 that is complementary to the inner profile IP.

[0038] The positive locking element 8 and the shaft 6 interlock in a form-locking manner, similar to a spur gear toothing.

[0039] For the axial stroke movement in the longitudinal direction X - X, the positive locking element 8 is guided along the shaft 6, or in its longitudinal direction X - X, by means of, for example, three radially projecting, outwardly extending, claw-like positive locking elements, which are uniformly spaced apart and formed on or out of its outer circumference, in a corresponding or complementary guide section 14. These claw-like positive locking elements form an outer profile AP of the positive locking element 8.

[0040] The guide section 14 is, for example, designed as a section of the locking actuator 4 and as such is attached, for example, to a housing section EM-G of an electric motor EM of an electric motor drive unit EM-AE (see Fig. 5The positive locking element 8 is supported against the housing section EM-G of the electric motor EM via this guide section 14 when the shaft 6 is locked. Thus, when the shaft 6 is locked, both static and dynamic torque loads from the drive train are transferred via this guide section 14 into the housing section or the housing EM-G of the electric motor EM.

[0041] Fig. 5 Figure 1 illustrates such an electric motor drive unit EM-AE of a powertrain, in particular of a vehicle, which includes the electric motor EM, a reduction gear RG and the proposed locking mechanism 2.

[0042] The locking actuator 4 is located opposite the end of the shaft 6 and is arranged coaxially to it, and is attached to the housing section EM-G of the electric motor EM (see also Figs. 1 to 3The proposed locking mechanism 2 is thus advantageously integrated into the electric motor EM. The locking actuator 4 is integrated into the electric motor housing EM-G. With regard to the aforementioned vehicle, the Fig. 5 thus a parking lock integrated into the EM electric motor.

[0043] The positive locking element 8 is connected to an electric drive EA of the locking actuator 4 via, for example, three screw fenders 12 aligned in the longitudinal direction X - X and elastically in the longitudinal direction X - X. These individual screw fenders 12 (mechanical energy storage devices) are guided by an associated pin element 26 and spaced uniformly apart from each other in the circumferential direction of the positive locking element 8. These individual pin elements 26 connect the positive locking element 8 to a closed, circumferential, annular, offset disc element 24 with a circumferential recess, spaced in the longitudinal direction X - X from the positive locking element 8. These helical springs 12 are arranged with a certain preload between this disc element 24 and the positive locking element 8. The pin elements 26 extend through the disc element 24 into the positive locking element 8, in which they are anchored.

[0044] The electric drive EA of the locking actuator 4 has a stator 18 which drives an internal rotor 16 with permanent magnets. The rotor 16 is designed in the form of a nut or threaded nut of a screw drive, which, depending on its direction of rotation (clockwise or counterclockwise), is movable in the longitudinal direction X - X along a threaded spindle 20 – advantageously hollow – with which it interacts, relative to the shaft end. This screw drive converts a rotational movement of the rotor 16 into an axial movement of the rotor 16 in the longitudinal direction X - X.

[0045] The threaded spindle 20 is connected to a housing G of the locking actuator 4 in a region at its end furthest from the shaft end and is stationary relative to it. The threaded spindle 20 extends through the recess of the disk element 24 and into a region in front of the positive locking element 8.

[0046] An axial bearing 22 is arranged between the rotor 16 and the disk element 24, through which the rotor 16 interacts with the disk element 24, which is only movable in the longitudinal direction X - X. The axial bearing 22 enables low-friction rotary movement of the rotor 16 relative to the disk element 24, which thereby performs a translational movement in the longitudinal direction X - X.

[0047] A disc-shaped in the Figs. 1 to 3 The element PCB shown illustrates a printed circuit board (PCB) for controlling the electric drive EA.

[0048] Fig. 4 The diagram schematically illustrates the functional connection between the locking actuator 4 and the shaft 6. The locking actuator 4 has an axially elastic section A ae in the longitudinal direction X - X and a torsionally elastic or torsionally flexible section A te.

[0049] Regarding the Figs. 1 to 3This axially elastic section A ae is implemented by the individual energy storage elements 12. These individual axially elastic energy storage elements 12 reduce axial impact loads or impacts in the longitudinal direction X - X associated with the joining process. Section A te, on the other hand, is implemented by the positive locking element 8.

[0050] Dynamic torque loads in the form of torque peaks of a drive train manifest themselves with respect to the locking mechanism 2 in the form of shock loads in the transverse direction Y - Y or Z - Z, which act on the locking actuator 4 or its positive locking element 8.

[0051] Fig. 4further illustrates the positive locking area FB between the positive locking element 8 and the shaft 6, as well as a movement clearance BS underlying this positive locking area FB between the inner profiling IP of the positive locking element 8 and the shaft-side profiling or shaft outer profiling 10, namely in the circumferential direction of the shaft 6.

[0052] This movement BS enables the shaft 6 to be locked by the positive locking element 8 as soon as the shaft 6 achieves a corresponding alignment to the positive locking element 8, which is necessary for a positive locking or joining of the joining elements 6, 8.

[0053] In the context of the aforementioned vehicle, this means that the vehicle can be locked or blocked in a parking situation where the vehicle is stationary, for example at the request of the driver.

[0054] If, in this parking situation, the orientation of shaft 6 is not such that it allows locking by the positive locking element 8, the positive locking element 8, in a state where its end face rests against shaft 6, can be pre-tensioned lengthwise to shaft 6 via the three coil springs 12 with a definable force to engage the shaft 6. If the shaft 6 is then rotated slightly further, the positive locking element 8 engages with the shaft 6 as soon as an orientation of the shaft 6 is achieved that allows engagement. Such further rotation of the shaft 6 in the parking situation can be initiated by the vehicle system.

[0055] However, the movement game BS also enables the following emergency scenario in case of a fault, in which the electric motor EM of the electric motor drive unit EM-AE fails.

[0056] If the electric motor EM of the electric motor drive unit EM-AE fails during driving in the aforementioned vehicle and the vehicle is subsequently braked to a standstill on a road with an incline, then the previously described locking mechanism 2 enables a locking or blocking of the vehicle as it rolls forward from a standstill, up to a maximum rotational speed of the shaft 6 or maximum speed of the vehicle, which depends on the movement clearance BS.

[0057] The positive locking element 8 is brought into engagement with the shaft 6 by utilizing the clearance BS and up to the maximum rotational speed of the shaft 6 or the maximum speed of the vehicle, which depends on the clearance BS. This is achieved by pre-tensioning the positive locking element 8, in a state where its end face rests against the shaft 6, along the shaft 6 via the three coil springs 12 with a definable force until it engages. The engagement occurs as soon as the shaft 6 achieves a corresponding alignment with the positive locking element 8.

[0058] Although the preceding description explains exemplary embodiments, it should be noted that a multitude of variations are possible. Furthermore, it should be emphasized that the exemplary embodiments are merely examples and are not intended to restrict the scope of protection, applications, or structure in any way. Rather, the preceding description provides the skilled person with a guideline for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as defined by the claims and these equivalent combinations of features.

Claims

1. Blocking mechanism (2), in particular for a vehicle, which comprises a blocking actuator (4) and a blockable shaft (6) of a drivetrain and is arranged between the blocking actuator (4) and the blockable shaft (6), in the case of which a form-fitting element (8), which can be electrically actuated in an axial stroke movement (X - X) and longitudinally in relation to the shaft (6), can, in a state in which said form-fitting element bears against an end face of a shaft-mounted complement (10) to which the form-fitting element (8) can be partially form-fittingly coupled, be biased longitudinally in relation to the shaft (6) against the shaft-mounted complement (10) by means of at least one elastic force transmission means (12) so as to be able to enter a latching engagement, wherein, in a blocked state of the shaft (6), in which the form-fitting element (8) and the shaft-mounted complement (10) engage in one another in a form-fitting region (FB) of the blocking mechanism (2), the form-fitting element (8) can be supported against a housing portion (EM-G) of an electric motor drive unit (EM-AE), on which the blocking actuator (4) can be mounted, wherein, in the form-fitting region (FB) and in the circumferential direction of the shaft (6), the blocking mechanism (2) has a movement clearance (BS) between the form-fitting element (8) and the shaft-mounted complement (10), characterized in that the blocking actuator (4) has an electric drive (EA) with a stator (18), which drives a rotor (16) lying inside it by means of permanent magnets, wherein the rotor (16) is in the form of a threaded nut of a screw drive (ST) which can be moved along a threaded spindle (20), with which it interacts, in the longitudinal direction (X - X), depending on its direction of rotation, wherein the form-fitting element (8) is attached to the movement mechanism of the blocking actuator (4) via the at least one elastic force transmission means (12), which movement mechanism brings about the axial stroke movement (X - X).

2. Blocking mechanism (2) according to Claim 1, wherein the shaft-mounted complement (10) is arranged in the region of an end of the shaft (6).

3. Blocking mechanism (2) according to Claim 2, wherein the blocking actuator (4) can be mounted on the end of the shaft (6) and thus in a manner situated opposite the housing portion (EM-G).

4. Blocking mechanism (2) according to Claim 3, wherein the form-fitting element (8) is arranged coaxially with the shaft (10).

5. Blocking mechanism (2) according to one of the preceding claims, wherein the form-fitting element (8) is shaped in the form of an annular element that runs around in closed fashion.

6. Blocking mechanism (2) according to one of the preceding claims, wherein the form-fitting element (8) has an inner profiling (IP) which form-fittingly interacts with a complementary profiling (10) of the shaft-mounted complement in the form-fitting region (FB).

7. Blocking mechanism (2) according to one of the preceding claims, wherein the form-fitting element (8) has an outer profiling (AP) which is complementary to a guide portion (14) of the blocking actuator (4) or of the housing portion (EM-G), via which guide portion the form-fitting element (8) is longitudinally guided for the axial stroke movement (X - X) and via which guide portion the form-fitting element (8) can be indirectly or directly supported against the housing portion (EM-G).

8. Blocking mechanism (2) according to one of the preceding claims, wherein the form-fitting element (8) can be supported against a housing portion of an electric motor housing (EM-G) or of a (reduction) gear housing (RG-G).

9. Electric motor drive unit (EM-AE) having a blocking mechanism (2) according to one of the preceding claims.

10. Vehicle having an electric motor drive unit (EM-AE) according to Claim 9 or a blocking mechanism (2) according to one of Claims 1 to 8.

11. Method for blocking a shaft (6) of a drivetrain, in particular of a vehicle, by means of a blocking mechanism (2) according to one of the preceding Claims 1 to 8, in the course of which method the form-fitting element (8) is brought into latching engagement with the shaft-mounted complement (10), utilizing the movement clearance (BS), up to a maximum rotational speed of the shaft (6) that depends on the movement clearance (BS), in that the form-fitting element (8), in a state in which it bears against an end face of the shaft-mounted complement (10), is biased longitudinally in relation to the shaft (6) and with a definable force against the shaft-mounted complement (10) via the at least one elastic force transmission means (12) until a latching engagement is obtained.

12. Method according to Claim 11, in the course of which, if the vehicle starts to move from a stationary position, a shaft (6) of the vehicle is blocked up to a maximum speed of the vehicle that depends on the movement clearance (BS).