Shift device for a transmission of a motor vehicle

Description

[0001] The invention relates to a switching device for a transmission of a motor vehicle, in particular a motor vehicle, according to the preamble of patent claim 1.

[0002] DE 10 2018 214 082 A1 discloses a claw for a clutch assembly in which the claw has a sensor contour on its outer circumference that extends in the circumferential direction. The extension of the sensor contour in the radial direction of the claw continuously changes in the circumferential direction within its rotational speed detection range, so that an outer contour of the rotation detection range does not have a region with a constant distance from the central axis.

[0003] DE 20 2011 050731 U describes a device for the synchronized switching of a positive-locking clutch, which has means for determining the angle of rotation between the first and the switching element of the clutch.

[0004] Such a shifting device for a transmission of a motor vehicle is already known, for example, from DE 10 2010 043 592 A1. The shifting device has at least one unsynchronized claw shifting element, i.e. an unsynchronized, positive-locking shifting element, which comprises two shifting parts rotatable relative to one another about a rotational axis. The shifting parts each have a shifting toothing. The shifting teeth face one another, for example, along the rotational axis. The shifting parts are displaceable relative to one another along the rotational axis between at least one coupling position and at least one decoupling position. In the coupling position, the shifting teeth engage with one another, so that in the coupling position the shifting teeth interact in a positive-locking manner. As a result, the shifting parts are connected to one another in a rotationally fixed manner. In the decoupling position, the shifting teeth are decoupled from one another.This means that in the uncoupling position the switching teeth do not mesh and therefore do not interact, so that in the uncoupling position the switching parts can rotate relative to each other around the axis of rotation.

[0005] The object of the present invention is to further develop a circuit device of the type mentioned at the outset and to create a method for operating the circuit device so that a particularly advantageous circuit can be realized.

[0006] This object is achieved by a circuit device having the features of patent claim 1. A further development of the invention is specified in dependent claim 2.

[0007] In order to further develop a switching device of the type specified in the preamble of patent claim 1 such that a particularly advantageous switching of the claw switching element, also simply referred to as a switching element, can be realized, in particular from the uncoupling position into the coupling position, a detection device, in particular an electrical or electronic one, is provided according to the generic type, by means of which rotational positions into which at least one of the switching parts can be rotated about the rotational axis relative to the other switching part, in particular in the uncoupling position, can be detected. In other words, in the uncoupling position, one switching part can be rotated about the rotational axis relative to the other switching part and thereby moved into the rotational positions, thus assuming the rotational positions relative to the other switching part.It is conceivable that the other switching part is fixed in a rotationally fixed manner to a housing of the transmission both in the uncoupled position and in the coupled position, in particular permanently, so that the other switching part cannot rotate about the axis of rotation relative to the housing. This means in particular that in the coupled position one switching part is fixed in a rotationally fixed manner to the housing via the other switching part. In the uncoupled position one switching part can be rotated about the axis of rotation relative to the other switching part and relative to the housing. Thus in the uncoupled position one switching part can be rotated about the axis of rotation relative to the housing and relative to the other switching part and thus moved into the rotational positions.In particular, by detecting the rotational positions, it is possible to determine or set the rotational positions of one switching part in relation to the other switching part and / or the housing, so that, based on the respective detected rotational position, a respective position, also referred to as the relative position or orientation, of one switching part relative to the other switching part can be determined or detected. In particular, the respective rotational position can be determined or detected as the respective position of one switching part relative to the other switching part, so that, for example, by detecting the respective rotational position, the respective position or orientation of one switching part relative to the other switching part is known.In particular, the detection device is designed to detect a rotational speed of one switching part, which rotates at the rotational speed about the rotational axis relative to the other switching part, particularly in the uncoupling position. Thus, it is conceivable that the detection device is a rotational speed detection system by means of which the rotational speed and thus the rotational positions of one switching part can be detected, i.e., measured.

[0008] Furthermore, according to the generic design, the switching device comprises an electronic computing device, also referred to as an electronic control device, which is designed to move the switching elements from the uncoupling position to the coupling position depending on the detected rotational positions. This allows the claw switching element, also referred to as a positive-locking switching element, to be switched without a so-called tooth-on-tooth position occurring. In other words, the switching elements can be moved from the uncoupling position to the coupling position without a so-called tooth-on-tooth position occurring.The invention is based in particular on the following findings: Conventionally, claw shift elements are synchronized by a pre-synchronization, particularly designed as a friction synchronization, in order to reduce or eliminate a differential speed between the shifting parts of the claw shift elements, whereupon the shift teeth can be engaged. This can lead to increased wear and possibly also to ratcheting, i.e., unwanted noises and thus a loss of comfort, particularly due to a tooth-on-tooth position.

[0009] The invention now makes it possible, on the one hand, to use the unsynchronized claw shift element, meaning at least to dispense with frictional synchronization of the claw shift element. On the other hand, the invention makes it possible to avoid tooth-on-tooth positions, particularly when moving the shifting parts from the uncoupled position to the coupled position, since the rotational positions, also referred to as angle of rotation positions, are detected, and to move the shifting parts from the uncoupled position to the coupled position depending on the detected angle of rotation positions. By taking the rotational positions into account, the electronic computing device can move the shifting parts from the uncoupled position to the coupled position in such a way that a tooth-on-tooth position does not occur, thus preventing increased wear and unwanted noise.The movement of the switching parts from the uncoupling position to the coupling position is also referred to as the engagement of the switching parts or of the claw switching element, which is also simply referred to as the claw. In particular, it is possible to specifically control the engagement of the claw depending on the detected rotational positions (rotational angle positions). In particular, in conjunction with a sufficiently accurate torque or speed sensor for detecting the rotational positions, such as an electric motor, and a suitable claw geometry, such as a catch and locking tooth design, a locking tooth or a first of the switching parts and / or the second switching part can be specifically controlled in order to avoid a tooth-on-tooth position when the claw engages and the resulting undesirable phenomena such as ratcheting, loss of comfort or unwanted noise.

[0010] Unsynchronized dog-type shift elements are cost-effective, space-saving, and technologically simple, as pre-synchronization, in particular frictional pre-synchronization, can be omitted. Particularly in a transmission for an electrified drive with an electric machine as the prime mover, where, for example, the first shifting part or the second shifting part, in particular one shifting part, is connected to the electric machine, in particular to a rotor of the electric machine, in particular in a rotationally fixed manner, the engagement of the dog, also known as the meshing process, can be controlled by means of the electric machine. Compared to an internal combustion engine, an electric machine can be controlled quickly and easily and can also be controlled to a speed of zero, so that synchronization of the dog is no longer necessary. As a result, meshing can be carried out with a high level of shifting comfort.

[0011] The motor vehicle is preferably driven, in particular purely electrically, so that the transmission is preferably a transmission of a vehicle that is driven, in particular purely electrically. The shifting parts are also referred to, for example, as shifting element halves. The respective shifting toothing has teeth, which are also referred to as claw teeth. It is conceivable that respective tooth ends of the claw teeth of the respective shifting part are directed axially, i.e. along the axis of rotation, towards the other, opposite shifting part, so that it is preferably provided that the shifting parts are arranged next to one another or one after the other in the axial direction, i.e. along the axis of rotation.Thus, the switching teeth of one switching part preferably face the other switching part, and the switching teeth of the other switching part face axially toward the one switching part, in particular such that the switching teeth of one switching part face axially toward the switching teeth of the other switching part, and the switching teeth of the other switching part face axially toward the switching teeth of the one switching part. Respective lengths of the respective claw teeth of the respective switching teeth extend, for example, for each switching part, axially from a specific, common axial reference plane to the respective tooth ends at which the respective teeth of the respective switching teeth end.

[0012] If the switching parts are in the coupling position, the claw switching element is in a closed state. It is preferably provided that, in the closed state of the claw switching element, the respective teeth of the respective switching toothing engage with claw gaps, also referred to as gaps or tooth spaces, of the respective other switching toothing, wherein the respective claw gaps of the respective switching toothing are arranged between the respective teeth of the respective switching toothing, in particular in the circumferential direction of the respective switching part extending around the rotational axis.

[0013] Furthermore, it is preferably provided that at least one of the claw teeth of the respective switching toothing is designed as a catch tooth, the length of which, in particular, is axial and thus runs along the axis of rotation and is greater than the lengths of other claw teeth of the respective switching toothing designed as locking teeth.

[0014] It has also proven particularly advantageous if the detection device comprises at least one sensor element and at least one transmitter element connected in a rotationally fixed manner to one switching part. The transmitter element is preferably a transmitter wheel. The sensor element is also referred to, for example, as a sensor. For example, the sensor element is connected in a rotationally fixed manner to the housing and / or in a rotationally fixed manner to the other switching part. Because the transmitter element is connected in a rotationally fixed manner to one switching part, the transmitter element can rotate with the one switching part about the rotation axis relative to the sensor element and in particular relative to the other switching part or to the housing. The transmitter element has transmitter segments.The sensor segments are arranged, for example, consecutively in the circumferential direction of the sensor element running around the rotational axis and, in particular, are spaced apart from one another such that a sensor gap, also simply referred to as a gap, is arranged between each two adjacent sensor segments. The sensor segments can be detected by means of the sensor element (sensor), so that the rotational positions of one switching part can be detected by detecting the sensor segments. In other words, for example, the respective rotational position is characterized by at least one of the sensor segments, so that the rotational positions can be detected by detecting the sensor segments, in particular as in a crankshaft sensor. The sensor element is designed, for example, to provide a signal, in particular an electrical signal, which characterizes the detected sensor segments and thus the rotational positions.For example, each sensor segment generates a respective pulse of the signal or sensor, so that the signal has a pulse for each sensor segment. Based on the signal pulses, the sensor segments and thus the rotational positions can be detected or determined. Thus, the sensor segments are also referred to as pulse-generating segments or pulse-generating sensor segments of the sensor element, in particular the sensor wheel.

[0015] According to the invention, it is provided that a number of the pulse-generating segments of the transmitter element corresponds at least to the sum of a number of teeth of the switching toothing of one switching part and a number of tooth gaps of the switching toothing of one switching part.

[0016] The feature that the electronic computing device is designed to move the switching parts from the uncoupling position into the coupling position depending on the detected rotational positions is to be understood in particular as meaning that the electronic computing device is designed to cause the switching parts to move from the uncoupling position into the coupling position. For this purpose, at least one of the switching parts or an actuator is controlled by means of the electronic computing device. Furthermore, it is preferably provided that the electronic computing device is designed to move the switching parts from the coupling position into the uncoupling position, thus causing the switching parts to move from the coupling position into the uncoupling position. Moving the switching parts from the uncoupling position into the coupling position is also referred to as engaging the claw switching element.Moving the switching components from the coupling position to the decoupling position is also referred to as disengaging the claw switching element. This allows the claw switching element to be engaged and disengaged using the electronic control unit.

[0017] As already indicated above, it is preferably provided that the first switching part and / or the second switching part, in particular with regard to the switching parts, exclusively one of the switching parts, is drivingly connected to an output of an electric machine or the aforementioned electric machine. This can be understood in particular to mean that the first and / or second switching part, in particular the one switching part, is rotationally fixedly connected to the output, in particular to a shaft, of the electric machine.

[0018] The claw shift element can be engaged with a high degree of shifting comfort, especially when the number of pulses, i.e., the number of encoder segments, is at least as high as the combined number of teeth and tooth gaps of the shift toothing of one shifting part. This results in what is known as absolute resolution, allowing the rotational positions of one shifting part to be detected with particular precision. For example, if the shift toothing has 60 teeth and thus 60 tooth gaps, the number of encoder segments is preferably 120, so the number of pulses is also 120.

[0019] In a further embodiment of the invention, the number of sensor segments is at least twice the previously described total. Thus, it is preferably provided that the number of sensor segments is at least four times the number of teeth of the switching gearing of one switching part.

[0020] According to the present invention, it is provided that the encoder element has a defect, also referred to as a missing gap, at which a first width of a first gap between two adjacent encoder segments of the encoder element, running in the circumferential direction of the encoder element around the rotational axis, is greater than second widths of second gaps running in the circumferential direction of the encoder element or all other gaps between adjacent encoder segments of the encoder element. Based on the defect, one of the rotational positions can be detected as a reference position or reference position, from which the other rotational positions can advantageously be detected or determined, in particular such that the claw switching element is only engaged, for example, in those rotational positions in which a tooth-on-tooth position does not occur.

[0021] Furthermore, it is preferably provided that a locking tooth is arranged between each two fangs.

[0022] Furthermore, it can preferably be provided that the claw shift element is designed as a claw brake, with the sensor connected to the other shifting part, which is permanently connected to the transmission housing, and the sensor element being permanently connected to the one, movable shifting part. This is advantageous in that, with the shifting part fixed to the housing, the meshing process can be controlled particularly precisely, since the sensor then has a zero speed and thus does not rotate about the rotational axis relative to the housing.

[0023] In a further embodiment of the invention, it is conceivable for the claw shift element to be designed as a claw clutch, wherein, for example, the other shifting part is connected in an output- or rotationally fixed manner to vehicle wheels or to at least or precisely one vehicle wheel of the motor vehicle. This allows a rotational speed of the other shifting part to be determined and thus known, wherein the rotational speed of the other shifting part can be determined from a speed of the motor vehicle, which is driven at this speed, for example, along a ground.

[0024] In a further embodiment, it is conceivable that the electronic computing device has or carries out a routine for a pulse assignment after the motor vehicle has been started with the claw switching element open for an assignment of angular positions or rotational positions to the pulses.

[0025] In a further embodiment of the invention, it is conceivable that the control device has a learning routine, in particular for implementation in the end-of-line test after and / or during vehicle production (EOL test (end-of-line test)) or after gearbox replacement during operation of the motor vehicle, which, when the claw switching element (switching element) is engaged, serves to assign for each pulse whether meshing can take place or not.

[0026] In a further embodiment, as an alternative to the teach-in routine, it is provided that the sensor wheel has a marking, notch, or the like, so that the angular position of the sensor wheel's faulty pulse relative to the sensor has the same fixed value in every production transmission. For example, if the sensor wheel has a marking and there is a requirement that the sensor wheel must always be installed in the same angular position, the teach-in routine can be omitted. In particular, it is conceivable that the pulse assignment routine, also referred to as teach-in, be performed in each newly installed transmission before the teach-in routine.

[0027] The missing point is also referred to as a missing pulse, whereby it is conceivable that exactly one or more missing points or missing pulses are provided. The sensor gap at the missing point, which is larger or wider than the other sensor gaps, means that two neighboring pulses of the signal are further apart from each other than the other neighboring pulses, so that the sensor gap or the missing pulse can be detected. All pulses following the missing pulse can be provided with an index so that a respective angular position or the respective rotational position of a switching part, which is connected in a rotationally fixed manner to a shaft, for example, can be determined. The number of pulses, which are generated, for example, by magnetized pole wheels or by teeth, is preferably considerably higher than the number of claw teeth, at least by a factor of four.Through targeted installation and / or a learning routine, the indices of the pulses or the indices of the areas between two pulses are assigned whether this corresponds to a gap or a tooth-on-tooth position. Using this information and a highly accurate speed sensor, the claw can be held in the gap position for engagement or meshing, thus avoiding a tooth-on-tooth position.

[0028] The drawing shows in the only figure a partial schematic representation of an embodiment of a switching device for a transmission of a motor vehicle according to the present invention.

[0029] The only figure shows a detail in a schematic representation of a shifting device 10 for a transmission of a motor vehicle, in particular a car. The transmission has a housing 12, which is shown particularly schematically in the figure. The shifting device 10 comprises at least one unsynchronized claw shift element 14, which is also simply referred to as a shift element or claw. For example, the motor vehicle comprises an electric machine, by means of which the motor vehicle can be driven, in particular purely electrically, in particular such that at least or exactly two vehicle wheels of the motor vehicle can be driven by means of the electric machine. The electric machine has a stator and a rotor which is rotatable relative to the stator and via which the motor vehicle can be driven. The claw shift element 14 has a first switching part 16 and a second switching part 18. As shown in Fig.As illustrated by a dashed arrow 20, the switching part 18 is rotatable about a rotation axis 22 relative to the switching part 16 and relative to the housing 12. In particular, it is conceivable that the switching part 16 is fixed to the housing 12 in a rotationally fixed manner and thus cannot be rotated about the rotation axis 22 relative to the housing 12. In particular, it is conceivable that the switching part 18 is connected to the rotor of the electric machine in a rotationally fixed manner.

[0030] The switching part 16 has a first switching toothing 24 with first teeth 26 and first tooth gaps 28 arranged between the teeth 26. The switching part 18 has a second switching toothing 30 with second teeth 32 and second tooth gaps 34 arranged between the teeth 32. It can be seen that the respective teeth 26 and 32 have respective lengths running parallel to the axis of rotation 22. The length of the teeth designated Z1 in the figure is greater than the length of the teeth designated Z2 in the figure, with the respective tooth Z1 also being referred to as a catch tooth and the respective tooth Z2 also being referred to as a locking tooth. For example, the claw switching element 14 and the switching toothings 24 and 30 are designed as described in DE 10 2012 043 592 A1.

[0031] The figure shows that the switching teeth 24 face the switching teeth 30 axially, i.e. along the axis of rotation 22, and the switching teeth 30 face the switching teeth 24 axially. The switching parts 16 and 18 are displaceable relative to one another along the axis of rotation 22 between at least one coupling position and at least one decoupling position shown in the figure. In the coupling position, the switching teeth 24 and 30 engage with one another, whereby the switching parts 16 and 18 are positively connected to one another in a rotationally fixed manner. In the decoupling position, the switching teeth 24 and 30 are decoupled from one another. This means that the switching teeth 24 and 30 do not engage with one another in the decoupling position, so that in the decoupling position the switching parts 16 and 18 can rotate relative to one another about the axis of rotation 22.A movement of the switching parts 16 and 18 from the uncoupling position into the coupling position is also referred to as meshing or meshing process or engagement of the claw switching element 14.

[0032] In order to be able to engage the claw switching element 14 particularly advantageously, the switching device 10 comprises a detection device 36, by means of which rotational positions into which the switching part 18 can be rotated about the rotational axis 22 relative to the switching part 16 and relative to the housing 12 can be detected or are detected. Furthermore, an electronic computing device 38, shown particularly schematically in the figure, is provided, by means of which the switching parts 16 and 18 can be moved from the uncoupling position into the coupling position depending on the detected rotational positions.

[0033] The detection device 36 has a sensor element 40, which is shown particularly schematically in the figure and is designed as a sensor wheel. The sensor element 40 and thus the pole pairs 42 (per tooth 32 and per tooth gap 34) are connected in a rotationally fixed manner to the switching part 18. The detection device 36 also comprises a sensor element 44, also simply referred to as a sensor, which is rotationally fixedly connected to the housing 12 and / or to the switching part 16. The pole pairs 42 are sensor segments of the sensor element 40 and can be detected by means of the sensor element 44. The sensor element 44 provides a signal 46, for example in the form of a raw signal, in particular an electrical signal, which has, in particular precisely, one pulse P for each detected pole pair 42.The encoder element 40 has a defect F, also referred to as a missing gap, at which a first width of a first gap between two adjacent pole pairs 42, extending in the circumferential direction of the encoder element 40 around the rotation axis 22, is greater than second widths of second gaps between adjacent pole pairs 42, extending in the circumferential direction of the encoder element. In the signal 46, the defect F is characterized in that a first distance between two adjacent pulses P of the signal 46 is greater than second distances between other pulses P of the signal 46. The defect F thus characterizes one of the rotational positions, so that this one rotational position can be used as a reference position or reference position. The reference position is thus known, for example, and thus a known position of the switching part 18 relative to the switching part 16.Starting from the reference position, those rotational positions can be determined or identified in which tooth-on-tooth positions do not occur when the claw engages. This allows the claw switching element 14 to be engaged particularly advantageously. List of reference symbols

[0034] 10Switching device 12Housing 14Switching element 16Switching part 18Switching part 20Arrow 22Rotation axis 24Switching toothing 26Tooth 28Tooth gap 30Switching toothing 32Tooth 34Tooth gap 36Detection device 38Electronic computing device 40Sensor element 42Pole pair 44Sensor element 46Signal FDefect point PPulse Z1Tooth Z2Tooth

Claims

1. Shifting device (10) for a transmission of a motor vehicle, having at least one unsynchronized claw shifting element (14) comprising two shifting parts (16, 18) which can be rotated relative to one another about an axis of rotation (22) and each have shifting teeth (24, 30) and are displaced relative to one another along the axis of rotation (22) between at least one coupling position, in which the shifting teeth (24, 30) engage with one another, as a result of which the shifting parts (16, 18) are connected to one another for conjoint rotation, and at least one decoupling position, in which the shifting teeth (24, 26) are decoupled from one another, as a result of which the shifting parts (16, 18) can be rotated relative to one another about the axis of rotation (22), wherein the shifting device has: - a detection device (36) by means of which rotational positions, in which at least one of the shifting parts (16, 18) can be rotated about the axis of rotation (22) relative to the other shifting part (16), can be detected, and - an electronic computing device (38) which is designed to move the shifting parts (16, 18) from the decoupling position to the coupling position depending on the detected rotational positions, wherein the detection device (36) comprises at least one sensor element (44) and at least one transmitter element (40) which is connected for conjoint rotation with one shifting part (18) and can thereby rotate with this one shifting part (18) about the axis of rotation (22) relative to the sensor element (44) and which has transmitter segments (42) which can be detected by means of the sensor element (44), so that the rotational positions of this one shifting part (18) can be detected by detecting the transmitter segments (42), characterized in that a number of the transmitter segments (42) corresponds at least to the sum of a number of teeth (32) of the shifting teeth (30) of this one shifting part (18) and a number of gaps (34) in the teeth of the shifting teeth (30) of this one shifting part (18), wherein the transmitter element (40) has a defect (F) at which a first width of a first gap between two adjacent transmitter segments (42) of the transmitter element (40) extending in the circumferential direction of the transmitter element (40) which extends about the axis of rotation (22) is greater than second widths of second gaps between adjacent transmitter segments (42) of the transmitter element (40) extending in the circumferential direction of the transmitter element (40).

2. Shifting device (10) according to claim 1, characterized in that the number of transmitter segments (42) is at least twice as large as the sum.