METHOD FOR OPERATING A DRIVE ARRANGEMENT, DRIVE ARRANGEMENT AND VEHICLE

Description

State of the art

[0001] The invention relates to a method for operating a drive arrangement, in particular for a vehicle, according to the preamble of claim 1, a drive arrangement, in particular for a vehicle, having features of claim 8, and a vehicle having features of claim 9.

[0002] In drive arrangements with an electric machine, it is generally intended that this can be coupled to and uncoupled from an output element, e.g. an output shaft. For such a coupling process, the speeds of the electric machine and the output element must be coordinated with one another. The uncoupled electric machine is generally stationary and not rotating. For the coupling process, the electric machine must be accelerated to a certain speed. During the coupling process, a tooth-on-tooth position occurs between the coupling elements, in which the teeth of the respective gears collide before the gears engage.

[0003] Such a tooth-on-tooth position leads to increased wear and power losses during a coupling process and is therefore undesirable.

[0004] DE 10 2013 204 227 A1 discloses a drive train and a method for performing a load change with a positive shifting element, wherein tooth-on-tooth positions are to be avoided. The drive train has an electric machine, a drive shaft, two gear ratios, an intermediate shaft, an output differential, a positive shifting element, and a frictional shifting element. During a shifting operation from one gear ratio to another, the positive shifting element is moved from one gear ratio (e.g., gear position A) to a neutral position, and the frictional shifting element is coupled to the other gear ratio by closing. When the frictional shifting element is closed, the positive shifting element can be coupled to the other gear ratio (e.g., gear position B).To release a tooth-on-tooth position, the frictional switching element can be opened slightly if necessary to allow engagement.

[0005] The disadvantage is that such a drive train has a complex structure with many components, such as two different shifting elements, which increases the drive system's susceptibility to malfunctions and errors. The use of a friction-locking shifting element, in particular, leads to significant wear.

[0006] DE 199 15 200 B4 discloses a method for shifting a transmission, wherein the transmission is designed as a CVT transmission and comprises a drive shaft and a clutch device designed as a claw clutch with shifting elements that can be brought into positive engagement. A first shifting element is coupled to the drive shaft in a rotationally fixed manner, wherein the drive shaft can be coupled to a second shifting element in a rotationally fixed manner during a clutching operation and can be decoupled from the second shifting element during a clutching operation. This document also discloses the use of a rotation sensor that outputs a pulse signal when a tooth of a gearing is moved past the rotation sensor.A relative angular position is determined from absolute values ​​of the angular positions of the switching elements with the aid of a count of the tooth pulses, starting from a state in which the claw of a first switching element is opposite a gap of the corresponding second switching element.

[0007] US 5 715 901 A discloses a drive arrangement for a vehicle, comprising an electric machine with a rotor shaft, a drive shaft, wherein the drive shaft is coupled to the rotor shaft of the electric machine such that the drive shaft can be driven by means of the electric machine, a coupling element and a transmission gear arranged on an output shaft, wherein the transmission gear is coupled to the coupling element such that the transmission gear can be driven by means of the coupling element, and a coupling device with a coupling element, wherein the coupling element is coupled to the drive shaft in a rotationally fixed manner,wherein the drive shaft can be coupled to the coupling element in a coupling process in a rotationally fixed manner and can be uncoupled from it in a decoupling process, and wherein during the coupling process a toothing of the coupling element and a toothing of the coupling element are brought into positive engagement with one another.

[0008] DE 10 2009 054 459 A1 discloses a detection device for detecting a differential position between two corresponding claws of two clutch elements, which is necessary during meshing in order to prevent a tooth-on-tooth position. Two Hall sensors are provided as the detection device, with each Hall sensor assigned to the claws of one of the two clutch elements. The signals from the Hall sensors are summed in an evaluation unit, with the respective alternating current component of the signals serving as a measure of the overlap of the corresponding claws.

[0009] DE 100 60 688 A1 discloses a method for engaging a positive-locking clutch, in which the relative rotational angle positions of the clutch halves are detected to prevent a tooth-to-tooth position of the clutch halves. Rotation angle sensors can be assigned to the shafts involved, which can be converted into the rotation angle of the clutch halves, taking into account the intermediate gear stages. Disclosure of the invention

[0010] According to the invention, a method for operating a drive arrangement, in particular for a vehicle, is proposed. The drive arrangement comprises an electric machine with a rotor shaft and a drive shaft. The drive shaft can be designed as an intermediate shaft. The drive shaft is coupled to the rotor shaft of the electric machine in such a way that the drive shaft can be driven (rotationally) by the electric machine.

[0011] The drive shaft is coupled in particular in a rotationally fixed manner or by means of a toothing (e.g. a spur gear stage) to a drive, in particular an electrical machine (electric motor).

[0012] The drive assembly further comprises a coupling element. This can be, for example, a toothing or gear / pinion coupled to an output shaft, an intermediate shaft, or a loose wheel arranged on the drive shaft.

[0013] The drive assembly further comprises a transmission gear arranged on an output shaft. The transmission gear is coupled to the coupling element in such a way that the transmission gear can be driven (rotationally) by means of the coupling element. The output shaft can be designed in the form of a differential with two output shafts.

[0014] The drive assembly further comprises a clutch device (clutch) with a clutch element (e.g., a movable or axially displaceable shift sleeve), wherein the clutch element is rotationally fixedly coupled to the drive shaft. The clutch element is rotationally fixedly coupled to the drive shaft, in particular by means of a gear arranged on the drive shaft or a guide hub with a toothing arranged on the drive shaft. The clutch element is displaceable, in particular, axially (i.e., along the longitudinal direction of the drive shaft or parallel to the central longitudinal axis of the drive shaft).

[0015] The drive shaft can be coupled to the coupling element in a rotationally fixed manner during a coupling process and decoupled from it during a decoupling process. During the coupling process, a toothing (in particular an internal toothing) of the coupling element and a toothing (in particular an external toothing) of the coupling element are brought into positive engagement with one another. For this purpose, the coupling element is displaced axially, in particular. In particular, the coupling element runs with its internal toothing on a corresponding external toothing of the guide hub or gear. The coupling element can rotate freely relative to the drive shaft, in particular in the decoupled state.

[0016] The drive assembly further includes a rotation sensor. The rotation sensor outputs a pulse signal when a tooth of a gear set on the transmission gear or a tooth of a sensor wheel non-rotatably coupled to the output shaft passes the rotation sensor (due to rotation of the transmission gear or the sensor wheel).

[0017] According to the invention, the absolute position of the transmission gear is redetermined from an absolute position of the rotor shaft of the electric machine, a transmission ratio between the coupling element and the rotor shaft, and a transmission ratio between the coupling element and the transmission gear in a coupled state of the coupling device (i.e., when the coupling element, the coupling element, and the drive shaft are rotationally fixedly coupled). For this purpose, the electric machine can comprise a sensor for determining the absolute position of the electric machine or the rotor (rotor shaft) of the electric machine. The transmission ratio refers to the ratio between the number and / or size of the teeth of two gear sets. This process can be referred to as restoring the absolute position of the transmission gear.

[0018] The rotation sensor is used in particular to detect a relative position of the transmission gear or sensor wheel.

[0019] In this case, detection means detecting the teeth of the gear wheel or the teeth of the encoder wheel rotating past the rotation sensor.

[0020] In this case, a relative position of the transmission gear or sensor wheel refers to the position of the teeth of the gearing of the transmission gear or sensor wheel, particularly in relation to the rotation sensor. In other words, it can be determined whether or not a tooth of the transmission gear or sensor wheel is located below the rotation sensor (or within its detection range).

[0021] The rotation sensor can be designed as a wheel speed sensor. In particular, the relative position of the transmission gear can be determined from the relative position of the sensor wheel by means of a conversion, and vice versa.

[0022] In this case, an absolute position of the transmission gear or the sensor wheel is determined depending on a previously stored absolute position of the transmission gear or sensor wheel and a counting of the pulse signals output by means of the rotation sensor.

[0023] In this case, an absolute position of the transmission gear or sensor wheel refers to the position of a specific tooth of the gearing of the transmission gear or sensor wheel, particularly in relation to the rotation sensor. In other words, it is possible to determine the rotational position of a specific tooth of the gearing of the transmission gear or sensor wheel.

[0024] It is conceivable that the absolute position of the transmission gear can be determined from the absolute position of the sensor wheel by means of conversion and vice versa.

[0025] The rotation sensor can be designed as a Hall sensor, for example, but other speed sensors are also conceivable.

[0026] The proposed design has the advantage, among other things, that the rotational speed of the electric motor can be synchronized during a clutch engagement using the pulse signal from the rotation sensor in such a way that a tooth-on-tooth position can be avoided or the period during which a tooth-on-tooth position occurs (tooth-on-tooth time) can be reduced. This reduces wear and minimizes power losses associated with the tooth-on-tooth position.

[0027] A tooth-on-tooth position refers to a position of two gears in which the teeth of both gears, particularly their radial surfaces, are in contact with each other, thus preventing meshing between the two gears. By reducing the tooth-on-tooth time, the coupling time of the entire coupling process can be reduced.

[0028] According to a further development, the absolute position of the transmission gear or the sensor wheel can be stored after at least one rotation cycle (in particular after several rotation cycles, in particular after each rotation cycle). The rotation cycle can correspond to one revolution of the transmission gear or the sensor wheel. The already stored absolute position can be overwritten with a new absolute position. Storing several absolute positions, in particular those determined one after the other, is also conceivable.

[0029] According to a further development, a relative position of the clutch element (i.e., the position of the teeth of the clutch element's gearing relative to the rotor shaft of the electric machine) can be determined from the absolute position of the rotor shaft of the electric machine. In particular, the transmission ratio between the rotor shaft and the clutch element can be used for this purpose.

[0030] According to a further development, a relative position of the coupling element (i.e., the position of the teeth of the coupling element's toothing relative to the toothing of the transmission gear) can be determined from the absolute position of the transmission gear. For this purpose, the transmission ratio between the transmission gear and the coupling element can be used, in particular.

[0031] According to a further development, the coupling process can be carried out depending on the relative position of the coupling element and / or the relative position of the coupling element. This can prevent the tooth-on-tooth position between the teeth of the coupling element and the coupling element, or at least shorten the corresponding tooth-on-tooth time.

[0032] According to a further development, the relative position of the clutch element can be adjusted before a clutch engagement by energizing the electric motor and / or increasing the speed of the rotor shaft (accelerating the rotor shaft). This can be done particularly when a vehicle with the drive assembly is stationary, i.e., when the transmission gear is not rotating.

[0033] According to a further development, the relative position of the clutch element can be adjusted depending on the relative position of the coupling element. The relative position of the coupling element does not change when the vehicle with the drive assembly is stationary, i.e., when the transmission gear is not rotating. The relative position of the clutch element can be adjusted or adapted to the relative position of the coupling element such that a clutch operation can be performed with a non-rotating transmission gear (e.g., when the vehicle with the drive assembly is stationary) without a tooth-on-tooth position or without a tooth-on-tooth time.

[0034] According to the invention, a drive arrangement, in particular for a vehicle, is proposed, wherein the drive arrangement is configured to be operated according to a method as described above. Regarding the advantages achievable thereby, reference is made to the relevant explanations of the method. The measures described in connection with the method can be used to further refine the drive arrangement.

[0035] The drive arrangement can, for example, be designed as an electric axle (E-axle) or form part of an E-axle.

[0036] According to the invention, a vehicle, in particular a motor vehicle, is proposed with a drive arrangement according to the above statements. Regarding the advantages achievable thereby, reference is made to the relevant statements regarding the drive arrangement. The measures described in connection with the drive arrangement or the method and / or those explained below can be used to further configure the vehicle.

[0037] An embodiment of the invention is explained below with reference to the accompanying drawings. They show: Figure 1 shows a schematic sectional view of a drive arrangement; Figure 2 shows a section of the schematic sectional view from Figure 1 ; Figure 3 shows a section of a schematic representation of the toothing of a coupling element, a coupling element and a guide hub before a coupling process; Figure 4 shows a schematic representation of the toothing according to Figure 3during the coupling process; Figure 5 a schematic representation of the gearing according to Figure 3 after the coupling process; and Figure 6 shows a schematic representation of a pulse signal output by means of a rotation sensor in comparison with a tooth position of a transmission gear and a coupling element.

[0038] Here, the method is explained using the drive assembly 10 shown in the figures as an example. The method is not limited to the drive assembly 10 shown, but can also be carried out on other drive assemblies with a clutch.

[0039] Figure 1 shows a schematic sectional view of the drive arrangement 10 and Figure 2 shows a section of the schematic sectional view according to Figure 1 .

[0040] The drive assembly 10 has a drive shaft 16. A gear 11 is arranged on the drive shaft 16 in a rotationally fixed manner. The drive shaft 16 is coupled to a rotor shaft 14 of an electric machine 12 by means of the gear 11, so that the electric machine 12 can drive the drive shaft 16.

[0041] In this case, the drive shaft 16 is designed as an intermediate shaft. An idler gear 13 is arranged on the drive shaft 16, which meshes with a gear 20 of an output shaft 19. A coupling element 18 is arranged on the idler gear 13 in a rotationally fixed manner. A sensor gear (not shown) can be arranged on the output shaft 19.

[0042] In the present case, the output shaft 19 is designed in the form of a differential 21 and two output shafts 17 coupled to the differential 21 (shown only schematically).

[0043] The drive arrangement 10 has a coupling device 22 with a coupling element 24. The coupling element 24 has a toothing 26 (internal toothing) and the coupling element 18 has a toothing 28 (external toothing) (see Fig.1 to 3 ).

[0044] A guide hub 25 with a toothing 27 (external toothing) is arranged on the drive shaft 16 in a rotationally fixed manner (cf. Fig.1 to 3 ). The coupling element 24 is arranged on the guide hub 25 in a rotationally fixed manner, wherein the (internal) toothing 26 of the coupling element 24 and the (external) toothing 27 of the guide hub 25 are in engagement with one another.

[0045] The clutch element 24 is designed to be axially displaceable. In other words, the clutch element 24 can be moved parallel to the central longitudinal axis 29 of the drive shaft 16. For this purpose, the clutch device 22 in the example has a shift fork 31, which can be driven or moved axially, i.e., parallel to the central longitudinal axis 29 of the drive shaft 16, by means of an electric drive 32.

[0046] The Figure 1 and 2 The drive arrangement 10 shown is in a state before a coupling process (coupling element 18 and coupling element 24 not (yet) coupled to one another).

[0047] The drive arrangement further comprises a rotation sensor 30 (cf. Figure 1 ).

[0048] Figure 3 shows a section of a schematic representation of the toothing 28 of the coupling element 18, the toothing 26 of the coupling element 24 and the toothing 27 of the guide hub 25 before the coupling process.

[0049] Before the coupling process, the toothing 26 of the coupling element 24 is arranged at a distance from the toothing 28 of the coupling element 18.

[0050] Figure 4 shows a schematic representation of the gears 26, 27, 28 according to Figure 3 during the clutch operation. In the example, the shift fork 31 (see Fig. 1 and 2 ) the coupling element 24 in the direction of the coupling element 18 (in Figure 4 to the left).

[0051] Depending on the relative position of the coupling element 24 and the coupling element 18, the teeth 28, 26 of the coupling element 24 and the coupling element 18 engage directly or, as in Fig. 4 shown, initially to a tooth-on-tooth position of the gears 26, 28. The Fig. 4The tooth-on-tooth position shown prevents engagement until the tooth-on-tooth position is overcome and the two gear teeth 28.26 can engage.

[0052] The tooth-to-tooth time can be reduced or prevented by performing the coupling process depending on the relative position of the toothing 26 of the coupling element 24 and / or the toothing 28 of the coupling element 18. The relative position of the toothing 26 of the coupling element 24 can be specifically adjusted by means of the electric machine 12.

[0053] Figure 5 shows a schematic representation of the gears 26, 27, 28 according to Figure 3 After the coupling process, the teeth 28 of the coupling element 18 and the teeth 26 of the coupling element 24 are now engaged with each other. Thus, the coupling element 18 and the coupling element 24 are coupled together in a rotationally fixed manner.

[0054] Figure 6shows, by way of example, a schematic representation of a pulse signal 34 output by means of the rotation sensor 30 in comparison to a tooth position of a transmission gear 20 and a coupling element 18.

[0055] As soon as a tooth 36 of the gearing of the gear wheel 20 is passed under the rotation sensor 30 (in Figure 6 indicated by an arrow pointing to the left), the rotation sensor generates a pulse 38. A plurality of pulses 38 in a time-dependent manner (in Figure 6 indicated by an arrow pointing to the right) results in a pulse signal 34. The pulses 38 correspond to the teeth 36 of the gearing of the gear wheel 20.

[0056] Thus, the relative position of the gear wheel 20 can be determined from the pulse signal 34 shown.

[0057] The transmission gear 20 is coupled to the coupling element 18 via the idler gear 13. Accordingly, the position of the teeth 40 of the toothing 28 of the coupling element 18 depends on the position of the teeth 36 of the toothing of the transmission gear 20.

[0058] Thus, the relative position of the coupling element 18 depends on the relative position of the transmission gear 20. Thus, the relative position of the coupling element 18 can be determined by means of a transmission ratio between the transmission gear 20 and the coupling element 18 and the relative position of the transmission gear 20, which can be determined from the pulse signal 34.

[0059] In this case, the different number and size of the teeth 36 of the gearing of the gear wheel 20 compared to the teeth 40 of the gearing 28 of the coupling element 18 determine the transmission ratio. The different number and size of the teeth 36 and 40 are in Figure 6indicated by rectangles of different sizes and their different numbers.

[0060] Accordingly, the relative position of the coupling element 18 and thus the position of its teeth 40 can be determined from the pulse signal 34 by means of the transmission ratio between the gear wheel 20 and the coupling element 18.

Claims

1. Method for operating a drive arrangement (10), in particular for a vehicle, comprising - an electric machine (12) with a rotor shaft (14), - a drive shaft (16), wherein the drive shaft (16) is coupled to the rotor shaft (14) of the electric machine (12) in such a way that the drive shaft (16) can be driven by means of the electric machine (12), - a coupling element (18), - a transmission gearwheel (20) which is arranged on an output shaft (19), wherein the transmission gearwheel (20) is coupled to the coupling element (18) in such a way that the transmission gearwheel (20) can be driven by means of the coupling element (18), - a clutch device (22) with a clutch element (24), wherein the clutch element (24) is coupled rotationally conjointly to the drive shaft (16), - wherein the drive shaft (16) can be coupled rotationally conjointly to the coupling element (18) in a coupling operation and can be decoupled therefrom in a decoupling operation, - wherein, during the coupling operation, a toothing (26) of the clutch element (24) and a toothing (28) of the coupling element (18) are brought into engagement with one another in a form-fitting manner, - a rotation sensor (30), wherein the rotation sensor (30) outputs a pulse signal (34) when a tooth (36) of a toothing of the transmission gearwheel (20) or a tooth of an encoder wheel coupled rotationally conjointly to the output shaft (19) is caused to pass the rotation sensor (30), - wherein an absolute position of the transmission gearwheel (20) is determined according to a previously stored absolute position of the transmission gearwheel (20) and counting of the pulse signals output by means of the rotation sensor (30), wherein the absolute position of the transmission gearwheel (20) is determined anew from an absolute position of the rotor shaft (14) of the electric machine (12), a transmission ratio between the clutch element (24) and the rotor shaft (14) and a transmission ratio between the coupling element (18) and the transmission gearwheel (20) in a coupled state of the clutch device (22).

2. Method according to Claim 1, characterized in that the absolute position of the transmission gearwheel (20) or the encoder wheel is stored after at least one rotation cycle, wherein the rotation cycle corresponds to a revolution of the transmission gearwheel or the encoder wheel.

3. Method according to Claim 1, characterized in that a relative position of the clutch element (24) is determined from the absolute position of the rotor shaft (14) of the electric machine (12), in particular via the transmission ratio between the rotor shaft (14) and the clutch element (24).

4. Method according to one of preceding Claims 1 and 3, characterized in that a relative position of the coupling element (18) is determined from the absolute position of the transmission gearwheel (20), in particular via the transmission ratio between the transmission gearwheel (20) and the coupling element (18).

5. Method according to Claim 4, characterized in that the coupling operation is carried out according to the relative position of the coupling element (18) and / or the relative position of the clutch element (24).

6. Method according to one of Claims 3 to 5, characterized in that the relative position of the clutch element (24) is set before a coupling operation by means of electrical energization of the electric machine (12) and / or increasing of a rotational speed of the rotor shaft (14).

7. Method according to Claim 6, characterized in that the relative position of the clutch element (24) is set according to the relative position of the coupling element (18).

8. Drive arrangement (10), in particular for a vehicle, characterized in that the drive arrangement (10) is configured to be operated according to a method according to one of Claims 1 to 7.

9. Vehicle, in particular a motor vehicle, having a drive arrangement according to Claim 8.