Method for designing a parking lock device of a transmission device of a motor vehicle, control device for carrying out the method, parking lock device, transmission device, axle drive, drive train and motor vehicle each with such a control device

Abstract

Method for disengaging a parking lock device (8) of a transmission device (2) of a motor vehicle (1), which transmission device (2) has an electric machine (3), the rotor shaft (5) of which is coupled, in particular directly, to a parking lock gear (9) of the parking lock device (8), which parking lock gear (9) has a locking contour (12) and can be locked by means of engagement of a locking element (10), in particular a parking lock pawl, in the locking contour (12), wherein the parking lock gear (9) is moved into a disengagement position by means of the electric machine (3) and the locking element (10) is disengaged in the disengagement position.

Description

The invention relates to a method for configuring a parking lock device of a transmission device of a motor vehicle, which transmission device has an electric machine, the rotor shaft of which is coupled, in particular directly, to a parking lock wheel of the parking lock device, which parking lock wheel has a locking contour and can be locked by means of engagement of a locking element, in particular a parking lock pawl, in the locking contour. In addition, the invention relates to a control device for carrying out the method, a parking lock device, a transmission device, a final drive, a drive train and a motor vehicle each having such a control device.Transmission devices which have a parking lock device or are coupled to such a parking lock device which is designed to lock the transmission device are fundamentally known from the prior art. For example, the parking lock device has a parking lock wheel which provides a locking contour, for example in the form of a toothing. The parking lock gear is coupled to a transmission element of the transmission device, such that when the parking lock gear is fixed, the transmission device is locked. For this purpose, the parking lock device provides a locking element, for example a parking lock pawl, which can engage in the locking contour. For example, a tooth is formed on the locking element, which tooth can be introduced into a gap of the locking contour in order to lock a further rotational movement of the parking lock gear.Depending on the present situation, a tensioning can occur after the locking element has been inserted into the locking contour between the locking element and the parking lock wheel. If the motor vehicle is stopped, for example, on a road gradient, the parking lock device is engaged and the vehicle brake of the motor vehicle is subsequently released, this leads to a bracing occurring between the parking lock wheel and the locking element. For example, the flank of the gap of the locking contour can press against the flank of the tooth on the locking element and clamp itself. In other words, the bracing in the transmission device or in the drive train is transmitted to the parking lock device, which prevents unintentional rolling away of the motor vehicle on the roadway gradient. If the parking lock device is to be disengaged again, this is possible only with an increased exertion of force, since the clamping holds the locking element in the locking contour. An actuator which actuates the parking lock device, for example pulls the locking element out of the locking contour, must be sufficiently dimensioned for this purpose. If the locking element is pulled out of the locking contour, this additionally leads to an abrupt release of the tension, which can be perceived by users of the motor vehicle.From the prior art, approaches are known to damp such a deployment stroke, wherein a complete elimination of the deployment stroke is nevertheless not possible, so that, in particular during a deployment process at a comparatively steep road gradient, deployment remains clearly perceptible even if the deployment stroke is damped. Furthermore, the damping of the deployment stroke does not provide any advantages with regard to the actuation of the locking element.DE 10 2017 121 007 A1 and DE 10 2009 023 498 A1 each disclose a parking lock and method for actuating the same.EP 3 919 783 B1 discloses a parking lock arrangement.The invention is based on the object of specifying a method, improved in comparison with this, for disengaging a parking lock device of a transmission device of a motor vehicle, in which disengagement impacts during disengagement of the parking lock device are prevented in particular.The object is achieved by the subject matters of the independent or subordinate claims. Advantageous embodiments are the subject matter of the dependent claims.As described above, the invention relates to a method for configuring a parking lock device of a transmission device of a motor vehicle. The transmission device has an electric machine, the rotor shaft of which is coupled to a parking lock wheel of the parking lock device. The coupling of the rotor shaft to the parking lock gear can basically be designed in any desired manner, in particular can be designed directly or indirectly. In other words, the parking lock gear can be arranged on the rotor shaft itself or on or on a gear element of the gear device coupled to the rotor shaft. As described, the parking lock wheel provides the locking contour in which a locking element can engage, so that when the locking element engages in the locking contour, the transmission device is locked. The blocking element can be designed, for example, as a parking pawl.The invention is based on the finding that the parking lock gear is moved by means of the electric machine into a disengagement position and the locking element is disengaged in the disengagement position. Instead of configuring the locking element in the initial position, in particular compensating or damping it with increased force exertion by the actuator and the disengagement stroke occurring in the process or thereafter, the present invention proposes moving the parking lock gear into a defined disengagement position by means of the electric machine, which is coupled to the parking lock gear via the rotor shaft. In other words, before the locking element is actually moved out of the locking contour, the parking lock wheel is first moved into an disengagement position. For this purpose, the electric machine can apply a torque to the parking lock gear, so that the parking lock gear is rotated. The relative position between the parking lock gear and the locking element, in particular between the locking contour and the section of the locking element engaging in the locking contour, which can be referred to as engagement section, is changed by means of the electric machine. As a result, even when the parking lock device is disengaged on a steep gradient of the road, the tension in the drive train or in the transmission device can be relieved by the electric machine by moving the parking lock wheel into the disengaged position.In other words, the electric machine "holds" the prestress in the transmission device, such that at least a reduced or no bracing is present between the blocking contour and the blocking element, and the blocking element can ultimately be designed with a reduced force or without overcoming a force which holds the blocking element in the blocking contour and is caused by a bracing. Consequently, after and / or when the locking element is deployed, i.e. after the engagement has been released from the locking contour, a significantly reduced or no deployment stroke occurs, such that the deployment stroke is reduced or completely eliminated or an occurrence of the deployment stroke is reduced or completely prevented in advance.The method can provide, in particular, that the locking element does not touch the flanks of the gap of the locking contour in which the locking element is engaged when the parking ratchet wheel is in the disengaged position, but rather the flanks of the locking element are detached from the flanks of the gap. In particular, the relative position between the parking lock wheel and the locking element can be set such that the locking element is located in the gap of the locking contour in a central position and a defined intermediate space is thus taken on both sides between the flanks of the locking element and the flanks of the gap of the locking contour.In addition to the locking element described herein, which is configured as a parking pawl, a further embodiment of the locking element is also possible, for example, as a claw element. Here, the parking lock gear forms a claw toothing which can be brought into engagement with the claw element as a locking element. The locking contour then represents the claw toothing of the parking lock gear, into which the corresponding claw toothing of the locking element can be brought into engagement. By placing the parking lock gear in the disengagement position, the teeth of the locking element are released from the teeth of the parking lock gear, so that disengagement without disengagement stroke is possible. The method can provide, in particular, that the parking lock wheel is first moved into the disengagement position, in which the locking element is released from the locking contour and the locking element is subsequently disengaged.The laying-out position can alternatively be understood as the position in which an actuator can lay out the blocking element. The disengagement position can thus be reached in which the electric machine rotates the parking lock gear, specifically until the locking element can be disengaged. In this case, a comparatively low contact can remain between the flanks of the blocking element and the flanks of the blocking contour, which however only produce a very low deflection stroke. Alternatively, as already described, the parking lock wheel is set in the disengagement position such that the locking element does not have any contact with the flanks of the locking contour and can therefore be disengaged without impact.According to a development of the described method, the parking lock wheel can be rotated by a specific angle or set to a specific angular position for being moved into the disengagement position. As described at the beginning, there is a coupling between the electric machine, in particular its rotor shaft, and the parking lock gear. If the electric machine is thus controlled in order to rotate the rotor shaft by a specific angle or to set it at a specific angular position, this is also directly or indirectly associated with positioning of the parking lock gear. This allows the rotor position sensor of the electric machine, which is provided anyway for controlling the electric machine, to be used for the actuation of the parking lock device. In other words, it is possible to determine to which position or by which angle the rotor shaft must be rotated in order to achieve a corresponding position of the parking lock gear in the disengagement position by a specific angle or to a specific angular position. In this case, the determined angle or the determined angular position can be selected such that the "gap center" is reached and the blocking element is thus located centrally in the gap of the blocking contour or is generally released from the flanks of the blocking contour.As described, there is at least one indirect relationship between the orientation of the rotor shaft of the rotor of the electric machine and the parking lock gear. The relationship between the rotor position of the electric machine rotor and the angular position of the parking gear may be determined or established. For example, it can be determined in which rotor position of the rotor the parking lock wheel has a corresponding orientation, for example how the relative position between the locking contour and the locking element is configured. Such a relationship can furthermore also be established, for example it can be predefined by corresponding alignment of the parking lock gear on the rotor shaft of the electric machine. It is thus known how the parking lock gear is set, namely depending on the specific orientation of the rotor of the electric machine.This can be used to correspondingly position the rotor of the electric machine for the specific movement of the parking lock wheel into the desired disengagement position, so that for the disengagement of the parking lock device for the movement of the parking lock wheel into the disengagement position, ultimately a control of the electric machine is sufficient. For this purpose, a control device can actuate the electric machine, so that the rotor is moved into the position which corresponds to the disengagement position of the parking lock gear. By coupling the rotor to the parking lock wheel by means of the rotor shaft, the parking lock wheel is likewise moved by the movement of the rotor, such that the disengagement position can be assumed.Furthermore, in the method, it can be provided that a tooth number of the parking lock gear corresponds to an integer multiple of a pole pair number of the electric machine, wherein the disengagement position is set by a defined orientation of the rotor of the electric machine. As described, in particular a direct coupling of the parking lock gear to the rotor shaft can be provided. Likewise, the parking lock gear can be arranged via further transmission elements, for example an intermediate transmission ratio, on a shaft of the transmission device, which is however coupled to the rotor shaft. If the number of teeth of the parking ratchet wheel is adjusted to the number of pole pairs of the electric machine, it can be ensured by simple actuation of the electric machine to assume a specific position of the rotor that the parking ratchet wheel is in the disengaged position in this position.By selecting the tooth number of the parking lock gear as an integer multiple of the pole pair number, in a concrete position of the rotor of the electric machine, the gaps in the locking contour also correspond to the corresponding disengagement position, so that the locking element can then be pulled out of the locking contour without clamping. In other words, the control device controls the electric machine such that the rotor is set in the defined orientation. In this orientation, the relationship of the number of pole pairs with the number of teeth can ensure that the blocking element is correspondingly located in the gap of the blocking contour and is not in contact with the flanks of the blocking contour, but rather can be designed comparatively easily.The described method includes referencing at least one parameter of the transmission device, in particular of the electric machine and / or of the parking lock gear. Specifically, the referencing of the parameter of the transmission device can be carried out at standstill, in particular at a neutral roadway gradient. In this case, for example, the electric machine can be used to rotate the parking lock gear, in particular slightly or minimally. If the parking lock device is engaged, i.e. the locking element is engaged in the locking contour, the gap width of the locking contour can be determined by targeted rotation of the parking lock wheel. In other words, it is possible to teach into which positions the rotor of the electric machine has to be moved in order to contact the flanks of the locking contour with the locking element.The disengagement position can then be taught, namely by setting the rotor of the electric machine or of the parking lock wheel into the disengagement position such that the locking element is released from the flanks of the locking contour. As the laying-out position, for example, that position can be defined which lies between the rotor positions in which the blocking element touches the flanks of the blocking contour. As described above, this may be related via coupling of the rotor shaft to the park ratchet. For example, if the parking lock gear is directly coupled to the rotor shaft, a direct relationship can be established between the rotor position and the position of the parking lock gear. In the case of indirect coupling, for example by means of an intermediate transmission ratio, this relationship can be converted via the respective transmission ratios. If the parameter of the transmission device has been referenced, it can be stored in the control device. Subsequently, for example even when parking on high road slopes, the learned parameters can be called up and the disengagement position of the parking lock wheel can thus be assumed.In the method, it can furthermore be provided that a gradient parameter, in particular of a roadway, is determined and the direction of movement is determined in which the parking lock wheel is moved into the disengagement position. The gradient parameter can be determined, for example, by means of a control device of the transmission device or of the motor vehicle or can be supplied to the latter. For example, a corresponding sensor can be provided in the transmission device or the motor vehicle, which can evaluate the current roadway gradient. The roadway gradient determines in which direction the bracing is present in the drive train or in the transmission device. In particular, it is thereby determined on which of the two opposite flanks of the gap of the locking contour the locking element abuts with its flank. From this, it is determined in which direction the electric machine is to rotate the parking lock wheel in order to reach the disengagement position.As described, depending on the present situation in which the motor vehicle is parked and the parking lock device is engaged, it may be necessary to compensate for a greater or comparatively smaller bracing in the transmission device. For this purpose, a gradient torque can be pilot controlled by the electric machine before and / or during the movement of the parking lock gear into the disengaged position. For example, as described above, the gradient parameter may be determined that indicates which roadway gradient is present. For this purpose, limit values can be defined, so that the electric machine pre-controls a gradient torque when a specific limit value of the gradient parameter is exceeded.This allows the bracing to be at least partially reduced by the pilot-controlled gradient moment. The transfer into the laying position can then be carried out more quickly. It is particularly advantageous here that in the laying position the locking element can be placed in the gap of the locking contour such that it does not bear either on the flank caused by the clamping or on an opposite flank. In other words, on the one hand, the locking element is prevented from bearing against a first flank of the gap of the locking contour on account of the clamping and, furthermore, the parking lock wheel is prevented from being rotated too far, such that the locking element would bear against the opposite flank. In the ideal case, the blocking element is thus moved centrally out of the gap of the blocking contour when the delivery position is assumed.As described, the parking lock gear can be arranged on the rotor shaft or can be coupled to the rotor shaft by means of an intermediate transmission ratio. In principle, the arrangement of the parking lock gear in the transmission device can be selected as desired. However, it is expedient to arrange the parking lock gear as close as possible to the rotor shaft of the electric machine. When the parking lock gear is arranged on the rotor shaft, the control of the electric machine is simplified, in particular when the number of teeth or the number of gaps of the locking contour of the parking lock gear is matched to the number of pole pairs of the electric machine, specifically forms an integer multiple.In addition to the method, the invention relates to a control device for a transmission device for a motor vehicle, which is designed for disengagement of a parking lock device of the transmission device of the motor vehicle, which transmission device has an electric machine, the rotor shaft of which is coupled, in particular directly, to a parking lock wheel of the parking lock device, which parking lock wheel has a locking contour and can be locked into the locking contour by means of engagement of a locking element, in particular a parking lock pawl, wherein the control device is designed to move the parking lock wheel into a disengagement position by means of the electric machine and to disengage the locking element in the disengagement position. The control device can in particular actuate the electric machine such that the rotor shaft and thus the coupled parking lock gear are moved into the disengagement position by movement of the rotor.The invention further relates to a parking lock device comprising a control device described above. The invention further relates to a transmission device which has an electric machine and a parking lock device described above. The invention also relates to a final drive which has a control device described above and / or a transmission device described above. The invention further relates to a drive train which has a previously described control device and / or a previously described transmission device and / or a previously described final drive. In addition, the invention relates to a motor vehicle which has a previously described control device and / or a previously described transmission device and / or a previously described final drive and / or a previously described drive train.All advantages, details and features described with respect to the method can be completely transferred to the control device, the parking lock device, the transmission device, the final drive, the drive train and the motor vehicle.The invention is explained below on the basis of exemplary embodiments with reference to the figures. The figures are schematic representations and show: FIG. 1 shows a schematic illustration of a motor vehicle; FIG. 2 shows a schematic illustration of a parking lock device in a engaged position; and FIG. 3 shows a schematic illustration of a parking lock device in an disengaged position.FIG. 1 shows a schematic illustration of a motor vehicle 1, comprising a transmission device 2. the transmission device 2 can be part of a drive train of the motor vehicle 1. The transmission device 2 has an electric machine 3 which is coupled to a control device 4. The control device 4 is basically designed to carry out the method described herein, in particular to actuate the electric machine 3. For example, the control device 4 can actuate the electric machine 3 such that a rotor of the electric machine 3 and thus a rotor shaft 5 coupled to the rotor assume a defined orientation.On the rotor shaft 5, a gear element 6 is schematically shown, which is in engagement with a gear element 7 of the gear device 2. These can be gearwheels. The transmission elements 6, 7 merely represent an example of any desired coupling of the electric machine 3 to further devices of the transmission device 2, for example a shiftable transmission device. The transmission device 2 further comprises a parking lock device 8 with a parking lock wheel 9 and a locking element 10. The embodiment of the parking lock device 8 is likewise illustrated merely by way of example. Instead of the illustrated embodiment of the locking element 10 as a parking pawl, the locking element 10 can likewise be designed as a claw element. In such an embodiment, the coupling between the parking lock gear 9 and the locking element 10 can be produced by the engagement of the claw tooth arrangements. In the illustration shown, the locking element 10 has a tooth 11 which can be introduced into a locking contour 12 (cf. FIGS. 2, 3 ) of the parking lock device 8. The locking contour 12 has teeth 13 and gaps 14 arranged in the circumferential direction of the parking lock wheel 9. As described, the blocking contour 12 can also be formed by a claw toothing.FIG. 2 shows the parking lock device 8 in an engaged state, in which the tooth 11 of the locking element 10 abuts a flank of the locking contour 12, in particular the gap 14. For example, the motor vehicle 1 can be placed on a slope, wherein the locking element 10 is introduced with the tooth 11 into the gap 14. After releasing the vehicle brake, the parking lock wheel 9 braces itself with respect to the locking element 10. releasing the locking element 10 in the state shown in FIG. 2 is only possible with difficulty, since the bracing between the parking lock wheel 9 and the locking element 10, in particular between the flank of the gap 14 and the tooth 11, makes it difficult to disengage. If the blocking element 10 can be pulled out of engagement, the clamping in the transmission device 2 would then be suddenly reduced, so that a disengagement strike would occur.In order to avoid this, the control device 4 controls the electric machine 3 in such a way that the parking lock gear 9 is moved according to arrow 15 into an disengagement position shown in FIG. 3. It can be seen that the locking element 10, in particular the tooth 11, is detached from the flanks of the gap 14 in the design position, so that intermediate spaces 16 are formed between the flanks of the tooth 11 and the flanks of the gap 14. In the disengaged position reached, which is illustrated in FIG. 3, it is thus possible to disengage the locking element 11 and thus disengage the entire parking lock device 8 without a disengagement strike occurring. Furthermore, the force which must be exerted on the blocking element 10 in order to configure the blocking element 10 is significantly reduced.For this purpose, a relationship between the rotor of the electric machine 3, in particular by the coupling of the parking lock gear 9 to the rotor shaft 5, can be utilized. For example, a tooth number of the teeth 13 of the blocking contour 12 is matched to the pole pair number of the electric machine 3. In particular, the number of teeth 13 of the blocking contour 12 forms an integer multiple of the number of pole pairs of the electric machine 3.In the method described herein, it can furthermore be provided that the motor vehicle 1 has at least one gradient sensor which can determine a roadway gradient. The ascertained road gradient can be supplied to the control device 4, so that the control device 4 correspondingly actuates the electric machine 3 in order to reach the disengagement position on the part of the parking lock gear 9.A referencing of the transmission device 2 can be carried out beforehand. For this purpose, the motor vehicle can stand in a neutral position, for example, in a standstill state, wherein the control device 4 actuates the electric machine 3 such that the parking lock gear 9 is moved until the tooth 11 of the locking element 10 first abuts a first flank of the gap 14 and subsequently abuts the opposite flank of the gap 14. As a result, the gap width can be measured and at the same time the relative position between the locking element 10 and the parking lock wheel 9, in particular the locking contour 12, can be determined. This makes it possible to learn the relationship between the blocking element 10 and the blocking contour 12, so that the rotor of the electric machine 3 can subsequently be adjusted in the same way that the desired laying position can be assumed, for example into a position between the previously learned end points of the gap.In addition to the direct arrangement of the parking lock gear 9 on the rotor shaft 5 or on the rotor shaft 5, it is shown by dashed lines that the parking lock gear 9 can also be arranged at any other location of the transmission device 2 as long as there is a coupling to the rotor shaft 5, so that the disengagement position on the part of the parking lock gear 9 can be reached by means of the electric machine 3.The method thus enables the control device 4 to ascertain the direction of the gradient, for example on a roadway gradient. This results in the direction in which the parking lock wheel 9 must be rotated in order to release the prestress between the parking lock wheel 9 and the locking element 10. If the roadway gradient exceeds a specific limit value of a gradient parameter, a gradient torque can be pre-controlled by the control device 4. The gradient torque can be applied to the parking lock wheel 9, for example, by means of the electric machine 3, in order to basically release a basic amount of the clamping. As a result, the laying position can subsequently be reached more quickly. Subsequently, a movement of the parking lock wheel 9 is generated by the relationship between the locking contour 12, the parking lock wheel 9, the locking element 10, the rotor shaft 5 and the rotor of the electric machine 3 such that the locking contour 12 moves relative to the locking element 10 such that the tooth 11 is released from the flanks of the gap 14. For example, it can be provided that the tooth 11 of the locking element 10 is positioned centrally in the gap 14. Subsequently, as is represented by an arrow 17 in FIG. 3, the parking lock device 8 can be designed by moving the locking element 10 with its tooth 11 out of the gap 14 of the locking contour 12.Reference numerals denote reference numerals1 Motor vehicle 2 Transmission device 3 Electric machine 4 Control device 5 Rotor shaft 6, 7 Transmission element 8 Parking lock device 9 Parking lock gear 10 Locking element 11 Tooth 12 Locking contour 13 Tooth 14 Gap 15 Arrow 16 Intermediate space

Claims

Method for configuring a parking lock device (8) of a transmission device (2) of a motor vehicle (1), which transmission device (2) has an electric machine (3), the rotor shaft (5) of which is coupled, in particular directly, to a parking lock wheel (9) of the parking lock device (8), which parking lock wheel (9) has a locking contour (12) and can be locked by means of engagement of a locking element (10), in particular a parking lock pawl, in the locking contour (12), wherein the parking lock wheel (9) is moved by means of the electric machine (3) into a disengagement position and the locking element (10) is configured in the disengagement position, characterized in that at least one parameter of the transmission device (2), in particular of the electric machine (3) and / or of the parking lock wheel (9), is referenced.Method according to Claim 1, characterized in that the parking lock wheel (9) is rotated by a specific angle or set to a specific angular position for being moved into the disengagement position.Method according to Claim 1 or 2, characterized in that a relationship between a rotor position of the rotor of the electric machine (3) and an angular position of the parking lock gear (9) is determined or established.Method according to one of the preceding claims, characterized in that a tooth number of the parking lock gear (9) corresponds to an integer multiple of a pole pair number of the electric machine (3), wherein the disengagement position is set by a defined orientation of the rotor of the electric machine (3).Method according to one of the preceding claims, characterized in that a gradient parameter, in particular of a roadway, is determined and the direction of movement in which the parking lock wheel (9) is moved into the disengagement position is determined.Method according to Claim 5, characterized in that a gradient moment is pilot-controlled by the electric machine (3) before and / or during the movement into the laying position.Method according to one of the preceding claims, characterized in that the parking lock wheel (9) is arranged on the rotor shaft (5) or is coupled to the rotor shaft (5) by means of an intermediate transmission ratio.Control device (4) for a transmission device (2) for a motor vehicle, which is designed for disengagement of a parking lock device (8) of the transmission device (2) of the motor vehicle, which transmission device (2) has an electric machine (3), the rotor shaft (5) of which is coupled, in particular directly, to a parking lock wheel (9) of the parking lock device (8), which parking lock wheel (9) has a locking contour (12) and can be locked by means of engagement of a locking element (10), in particular a parking lock pawl, in the locking contour (12), characterized in that the control device (4) is designed for carrying out the method according to one of the preceding claims.Parking lock device (8) with control device (4) according to the preceding claim.Transmission device (2) comprising an electric machine (3), a parking lock device (8) and a control device (4) according to claim 8.Final drive comprising a control device (4) according to claim 8 and / or a transmission device (2) according to the preceding claim.Drive train, comprising a control device (4) according to Claim 8 and / or a transmission device (2) according to Claim 10 and / or a final drive according to the preceding claim.Motor vehicle (1) comprising a control device (4) according to claim 8 and / or a transmission device (2) according to claim 10 and / or a final drive according to claim 11 and / or a drive train according to the preceding claim.

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