METHOD AND DEVICE FOR ACTUATING A DOG CLUTCH OF A MANUAL TRANSMISSION OF AN ELECTRICALLY DRIVEABLE VEHICLE

Abstract

The present disclosure relates to a method and a device for actuating a dog clutch (6) of a manual transmission (2) of an electrically driveable vehicle (1), in which at least relative rotational speeds and/or rotational angle positions of a sliding sleeve (7) and of a coupling element (12) relative to each other are determined, in order to avoid a possible tooth-to-tooth position. In the case of a predicted tooth-to-tooth position, control measures are carried out, which change the relative rotational angle position of the sliding sleeve (7) and of the coupling element (12) relative to each other and/or the duration of the movement of the sliding sleeve (7) in such a way that, when an engagement position is reached, delay-free form-fitting meshing of associated sets of dog teeth (10, 13) is carried out.

Claims

1. A method for actuating a dog clutch (6) of a manual transmission (2) of an electrically driveable vehicle (1), wherein the manual transmission (2) has an input shaft (3) and an output shaft (4), wherein the input shaft (3) has a drive connection to an electric drive machine (5) of the vehicle (1), wherein a sliding sleeve (7) is co-rotationally and axially displaceably arranged on the input shaft (3) or another transmission shaft connected to the input shaft (3) and has first dog teeth (10), wherein a coupling element (12) is rotatably and axially non-displaceably arranged on the input shaft (3), wherein the coupling element is drivingly coupled with the output shaft (4) or another transmission shaft connected to the output shaft (4), wherein the coupling element (12) has second dog teeth (13), the method comprising: axially moving the sliding sleeve (7) by way of a switching element (15) actuated by an electric actuator (16) and producing a form-fitting connection to the coupling element (12) by coupling the first and second dog teeth (11, 13), and determining at least relative rotational speeds and/or rotational angle positions of the sliding sleeve (7) and of the coupling element (12) that are rotatable relative to each other, in order to produce the form-fitting connection, controlling electronically, as a function of the determined rotational speeds and/or rotational angle positions, the at least one electric drive machine (5) and/or the electric actuator (16) to avoid a tooth-to-tooth position of the first and second dog teeth (10, 13) when the sliding sleeve (7) is displaced to couple the first and second dog teeth (10, 13), wherein, to produce the form-fitting connection by coupling of the two sets of dog teeth (10, 13), at the time of the actuation of the sliding sleeve (7), starting from a defined neutral position, the rotational angle positions and the rotational speeds of the sliding sleeve (7) and of the coupling element (12) relative to each other are determined, wherein, starting from the time of the actuation of the sliding sleeve (7), calculating an anticipated engagement time relating to meshing of the dog teeth (10) of the sliding sleeve (7) in the dog teeth (13) of the coupling element (12) at a defined engagement position by using a predefined actuating speed curve and the previously determined actuating travel of the sliding sleeve (7) between its neutral position and its engagement position, calculating the anticipated rotational angle positions of the sliding sleeve (7) and of the coupling element (12) relative to each other at the engagement time, predicting a tooth-to-tooth position or no tooth-to-tooth position at the calculated engagement time by using the anticipated rotational angle positions of the sliding sleeve (7) and of the coupling element (12) relative to each other, and wherein, in the case of a predicted tooth-to-tooth position, carrying out control measures on the at least one electric drive machine (5) and/or on the electric actuator (16) actuating the sliding sleeve (7) and avoiding the tooth-to-tooth position as a result of the control measures such that when the engagement position is reached, form-fitting meshing of the sets of dog teeth (10, 13) is carried out.

2. The method according to claim 1, wherein the meshing of the sets of dog teeth is delay-free.

3. The method according to claim 1, wherein the control measures change the relative rotational angle positions of the sliding sleeve (7) and of the coupling element (12) relative to each other in such a way that when the engagement position is reached, the form-fitting meshing of the sets of dog teeth (10, 13) is carried out.

4. The method according to claim 1, wherein the control measures change the duration of the movement of the sliding sleeve (7) during the switching operation in such a way that when the engagement position is reached, the form-fitting meshing of the sets of dog teeth (10, 13) is carried out.

5. The method according to claim 1, wherein in the case of a predicted tooth-to-tooth position, the rotational speed of the at least one input shaft (3) is changed by way of changing the rotational speed of the at least one electric drive machine (5) such that the rotational angle position of the sliding sleeve (7) co-rotationally connected to the input shaft (3) permits delay-free meshing of the dog teeth of the sliding sleeve (7) and the coupling element (12) when they reach the engagement position.

6. The method according to claim 1, wherein in the case of a predicted tooth-to-tooth position, initially starting from the time of actuation of the sliding sleeve (7) a new engagement time is calculated at which the rotational angle positions of the sliding sleeve (7) and the coupling element (12) relative to each other permit the dog teeth (10, 13) to mesh.

7. The method according to claim 6, wherein a new actuating speed curve of the sliding sleeve (7) matched to the new engagement time is then calculated.

8. The method according to claim 7, wherein the sliding sleeve (7) is then displaced axially by way of the electric actuator (16) in accordance with the calculated new actuating speed curve in order, when the engagement position is reached, to mesh the dog teeth (10) of the sliding sleeve (7) without delay in the dog teeth (13) of the coupling element (12) in a form-fitting manner.

9. The method according to claim 8, wherein, starting from the time of actuation of the sliding sleeve, an actuating speed of the sliding sleeve rises linearly as the sliding sleeve approaches the engagement position.

10. The method according to claim 9, wherein, at the engagement position, the sliding sleeve engages the coupling element without delay.

11. The method according to claim 10, wherein, after engagement, the actuating speed of the sliding sleeve continues to rise linearly.

12. The method according to claim 1, wherein the meshing of the sets of dog teeth is carried out without braking the sliding sleeve.

13. The method according to claim 3, wherein the control measures also change the duration of the movement of the sliding sleeve (7) during the switching operation in such a way that when the engagement position is reached, the form-fitting meshing of the sets of dog teeth (10, 13) is carried out.

14. The method according to claim 1, wherein the time to achieve meshed engagement is shorter relative to a non-linear actuating speed curve of the sliding sleeve having braking and a neutral position state of the sliding sleeve at the engagement position.

15. The method according to claim 1, wherein an actuating speed curve of the sliding sleeve is substantially linear and constant.

16. A device (17) for actuating a dog clutch (6) of a manual transmission (2) of an electrically driveable vehicle (1), wherein the manual transmission (2) has at least one input shaft (3) and an output shaft (4), wherein the input shaft (3) has a drive connection to at least one electric drive machine (5) of the vehicle (1), the device comprising: a sliding sleeve (7) co-rotationally and axially displaceably arranged on the input shaft (3) or another transmission shaft that is connected to the input shaft (3) and has first dog teeth (10), wherein a coupling element (12) rotatably arranged on the input shaft and axially non-displaceably arranged on the input shaft (3), wherein the coupling element is drivingly coupled with the output shaft (4) or another transmission shaft that is connected to the output shaft (4); wherein the coupling element has second dog teeth (13), wherein the sliding sleeve (7) is axially movable by way of a switching element (15) which is actuated by an electric actuator (16) in order to produce a form-fitting connection to the coupling element (12), a sensor device (18) which is configured for direct and/or indirect detection of rotational angle positions and/or rotational speeds of the sliding sleeve (7) and of the coupling element (12) from sensor measured values and/or from control data of the at least one electric drive machine (5), an electronic control device (20), which is configured to evaluate the detected rotational angle position data and/or rotational speed data of the sliding sleeve (7) and of the coupling element (12) and to control the at least one electric drive machine (5) and the electric actuator (16) as a function of the rotational speed values and/or rotational angle position values.

17. A vehicle (1) having an electric drive and a device (17) for actuating the dog clutch (6) of the manual transmission (2), wherein the device (17) carries out the method according to claim 1.

18. A vehicle (1) having an electric drive the device (17) for actuating the dog clutch (6) of the manual transmission (2) according to claim 16.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present disclosure will be explained in more detail below with reference to an exemplary embodiment illustrated in the appended drawings. In the drawings:

[0044] FIG. 1 shows a schematic illustration of a commercial vehicle having a device according to the present disclosure,

[0045] FIG. 2 shows a schematic view of a dog clutch in the vehicle according to FIG. 1,

[0046] FIG. 3 shows a diagram relating to the actuation of a sliding sleeve of the dog clutch, and

[0047] FIG. 4 shows a flow chart relating to carrying out the method according to the present disclosure for actuating the dog clutch.

DETAILED DESCRIPTION

[0048] Some structural elements in the figures correspond, so that they are designated by the same reference numbers.

[0049] The commercial vehicle 1 illustrated in FIG. 1 has, as is known, two front wheels 23a, 23b, two rear wheels 24a, 24b, an electric drive machine 5 and a manual transmission 2. The manual transmission 2 has an input shaft 3 and an output shaft 4. The output shaft 4 has a drive connection to a cardan shaft 4a. The input shaft 3 has a drive connection to the electric drive machine 5 or can have a drive connection to the drive machine 5 via a clutch, not illustrated. The cardan shaft 4a has a drive connection to two rear axle shafts 22a, 22b via a differential gearbox 21, which have a respective drive connection to a rear wheel 24a, 24b. The electric drive machine 5 is assigned an engine control unit 5a, with which the drive machine 5 can be controlled. The manual transmission 2 has at least two transmission stages, which can be switched alternately by way of at least one non-synchronized dog clutch 6.

[0050] The design structure of the dog clutch 6 is illustrated schematically in FIG. 2. The dog clutch 6 in this example is designed to switch alternately between a first gear G1 and a reverse gear RG via a neutral position in the centre of the actuating travel. The idler gear 11 of the first gear G1, namely a forward gear, and the idler gear 27 of the reverse gear RG are similar in structure. The description of the method according to the present disclosure is therefore carried out only for a switching operation of the dog clutch 6 from the neutral position of the manual transmission 2 into the first gear G1. It is possible here to dispense with a comparable description of the switching of the manual transmission 2 from the neutral position into the reverse gear RG and the associated co-rotational coupling of the reverse gear idler gear 27 to the input shaft 3.

[0051] The manual transmission 2 is switched by way of a sliding sleeve 7, which, via driver toothing 8, is axially displaceably and co-rotationally arranged on the input shaft 3. The driver toothing 8 is formed on the radially inner circumference of a hollow-cylindrical main body 9 of the sliding sleeve 7, which is formed in axial toothing on the radial circumference of the input shaft 3. Formed on the radially outer circumference of the main body 9 of the sliding sleeve 7 is first switching toothing in the form of first dog teeth 10, which extends in the direction of the idler gear 11 of the first gear G1.

[0052] The first gear G1 of the manual transmission 2 is illustrated here only by an idler gear 11, which is rotatably and axially fixedly arranged on the input shaft 3. This idler gear 11 meshes with a fixed gear, not illustrated, of the first gear G1, which is co-rotationally and axially non-displaceably arranged on the output shaft 4 or on a layshaft that has a drive connection to the output shaft 4. A coupling element 12 in the form of a supporting ring is moulded onto the idler gear 11 of the first gear G1. A second set of switching teeth in the form of a second set of dog teeth 13 extends from the coupling element 12 radially inwards and axially in one piece in the direction of the sliding sleeve 7. The two sets of dog teeth, i.e. the dog teeth 10 of the sliding sleeve 7 and the dog teeth 13 on the coupling element 12 of the idler gear 11, are designed as mutually complementary sets of teeth, which can be connected to each other by a form fit and separated from each other by an axial displacement of the sliding sleeve 7.

[0053] The main body 9 of the sliding sleeve 7 additionally has a coupling point for an actuating mechanism in the form of a central guide groove 14 formed in the circumferential direction, in which one end of a switching element 15 in the form of a selector fork engages loosely so that, by way of the switching element 15, the sliding sleeve 7 is coupled with a force fit in the axial direction and rotatably in the circumferential direction. The radially outer end of the switching element 15 has a drive connection to an electric actuator 16. The electric actuator 16 has a rotary electric drive and can be formed in a known design, which is not specifically illustrated in FIG. 2. The drive connection is formed in such a way that a rotational movement of the rotary drive of the actuator 16 is converted into a translational movement of the switching element 15 while driving the sliding sleeve 7 on the input shaft 3. For the present disclosure, it is merely important that the actuator 16 is electronically controllable.

[0054] A device 17 for actuating the manual transmission 2, in particular for actuating at least one dog clutch of the design of the dog clutch 6 just described and according to FIG. 2, is illustrated highly schematically and in simplified form in FIG. 1. The device 17 has a sensor device 18 and an electronic control device 20. The sensor device 18 is designed to determine rotational speeds and rotational angle positions of the components of the dog clutch 6 that are rotatable relative to one another on the input and output side, i.e., in the present case, the sliding sleeve 7 having the first set of dog teeth 10 and the idler gear 11 of the first gear G1 having the coupling element 13 and its second set of dog teeth 13. For this purpose, the input of the sensor device 18 is connected to the engine control unit 5a, and the output has a wired or wire-free signal connection to the electronic control device 20. The arrow 28 illustrates that the sensor device 18 can also determine the aforementioned values within the manual transmission 2.

[0055] The sensor device 18 is capable of detecting rotational speeds and rotational angle positions of the input shaft 3 which, for example, are made available by the engine control unit 5a, and of providing them to the electronic control device 20 for further processing. In the electronic control device 20, the rotational speed and the rotational angle position of components that have or can have an indirect or direct drive connection to the input shaft 3, i.e., in the present case, the rotational speed and the rotational angle position of the sliding sleeve 7 with its first set of dog teeth 10, can be determined from the rotational speed data and rotational angle position data of the input shaft 3 transmitted by the engine control unit 5a.

[0056] The sensor device 18 additionally has at least one sensor 19 which, in the present case, is arranged on the output shaft 4, in order to determine the rotational speed and the rotational angle position of the output shaft 4. The sensor 19 can be, for example, a sensor element of known design, which is based on an inductive measurement principle or on the Hall effect and interacts with an incremental wheel which is fastened to the output shaft 4. In a manual transmission having a plurality of dog clutches and having further transmission shafts, there can also be further sensors for detecting rotational speeds and rotational angle positions of the components rotating relative to one another. In any case, via the rotational speed and rotational angle position of the output shaft 4, determined by the sensor 19, the rotational speed and the rotational angle position of the idler gear 11 of the first gear G1 and/or of the coupling element 12 having the second set of dog teeth 13 can be determined in the electronic sensor device 18 while taking the transmission ratio of the relevant gear into account.

[0057] The output of the electronic control device 20 has a wired or wire-free signal connection to the engine control unit 5a and to the electric actuator 16 for the actuation of the sliding sleeve 7. As a result, the electronic control device 20 is capable of influencing the rotational speed of the electric drive machine 5 via the engine control unit 5a during switching processes of the manual transmission 2. In addition, the electronic control device 20 can change the actuation of the sliding sleeve 7 with regard to the actuation time, the actuating speed and the actuating duration by controlling the electric actuator 16.

[0058] To this end, FIG. 3 shows a displacement-time diagram, in which a first actuating speed curve 26 for an exemplary time profile of the actuation of the sliding sleeve 7 during a gear change of the manual transmission 2 is illustrated. Accordingly, the axial displacement of the sliding sleeve 7 in the engagement direction of the dog clutch 6 is started at an actuation time to. At this time to, the sliding sleeve 7 is in a neutral position so, i.e. in a disengaged state of the dog clutch 6. The sliding sleeve 7 is then accelerated nonlinearly until, at an engagement time t.sub.1, it has reached an engagement position s.sub.1, that is to say that axial position in which the opposite outermost ends at the front of the dogs of the two sets of dog teeth 10, 13 to be coupled to one another are arranged on an imaginary line.

[0059] In this engagement position s.sub.1, the sliding sleeve 7 is braked virtually completely in a short time period in order to mesh the two sets of dog teeth 10, 13 in each other. As soon as the meshing process begins successfully, the actuating speed s(t) of the sliding sleeve 7 rises linearly according to the first actuating speed curve 26 until, after a comparatively long first actuating time period t, the dog clutch 6 is completely engaged in an end position s.sub.2 at an end time t.sub.2 and therefore the form-fitting connection of the dog clutch 6 has been produced. This first actuating speed curve 26 is illustrated only in simplified form and is to be understood as exemplary.

[0060] A procedure of a method according to the present disclosure, described below, permits the utilisation of a substantially linear, second actuating speed curve 25 for the displacement movement of the sliding sleeve 7 at a virtually constant actuating speed s(t). Here, after an initial short linear acceleration phase as the engagement position s.sub.1 is reached, the sliding sleeve 7 needs not to be braked or barely needs to be braked, instead the sets of dog teeth 10, 13 can be meshed in one another virtually without delay. Accordingly, as FIG. 3 shows, the dog clutch 6 is completely engaged after a detectably shorter second actuating time period t* at an earlier end time t.sub.2 of the sliding sleeve movement.

[0061] A method having the features of the present disclosure can be carried out on the vehicle 1 according to FIG. 1 and will be described below by using a flow chart illustrated in FIG. 4. The manual transmission 2 operates by way of example by using an algorithm which is completely or partly stored in the control device 20 and operated there. According to this algorithm, as FIG. 4 illustrates, the following method steps are provided:

[0062] Step S1: The method begins with the preparation of a gear change of the manual transmission 2, in which the previous gear has already been disengaged and a new gear, here the first gear G1, is to be engaged. For this purpose, the sliding sleeve 7 is set in a previously defined and stored neutral position so, from which the first gear G1 is to be engaged.

[0063] Step S2: By using the previously stored values of the first contour K.sub.1 of the first set of dog teeth 10 of the sliding sleeve 7 and the likewise stored values of the second contour K.sub.2 of the second set of dog teeth 13 of the coupling element 12 of the idler gear 11, a relative rotational angle position .sub.soll of the sets of dog teeth 10, 13 relative to each other which reliably permits meshing of the dog clutch 6 while avoiding a tooth-to-tooth position is determined.

[0064] Step S3: At a time to the actuator 16 is activated to be actuated, as a result of which the sliding sleeve 7 is set moving at an actuating speed s(t) according to the linear actuating speed curve 25. At this actuation time to the detected information from the sensor device 18, which is the rotational speed n.sub.1 and the rotational angle position .sub.1 of the sliding sleeve 7 and also the rotational speed n.sub.2 and the rotational angle position .sub.2 of the idler gear 11, is determined and, from this, the current rotational angle position (t.sub.0) of these two relative to each other at the actuation time t.sub.0 is calculated.

[0065] Step S4: By using the previously stored actuating travel s of the sliding sleeve 7 between the neutral position so and the engagement position s.sub.1 and also the actuating speed s(t) or according to the linear actuating speed curve 25, an anticipated engagement time t.sub.1 of the sliding sleeve 7 is determined.

[0066] Step S5: By using the information previously read in or determined, the anticipated rotational angle positions .sub.1 (t.sub.1), .sub.2 (t.sub.1) of the two sets of dog teeth 10, 13 and, from this, an anticipated relative rotational angle position (t.sub.1) of the two sets of dog teeth 10, 13 relative to each other at the anticipated engagement time t.sub.1 of the sliding sleeve 7 are determined. The rotational speeds n.sub.1, n.sub.2 of the sliding sleeve 7 and of the idler gear 11 can be assumed to be constant to a first approximation for the actuating time period of the sliding sleeve 7. If appropriate, rotational speed changes of the sliding sleeve 7 and/or of the idler gear 11 can be detected continuously by the sensor device 18 and extrapolated for the anticipated engagement time t.sub.1.

[0067] Step S6: The predicted relative angle position (t.sub.1) of the two sets of dog teeth 10, 13 is compared with the target rotational angle position .sub.soll. In the case of a relevant deviation which would result in an undesired tooth-to-tooth position in the engagement position s.sub.1, a countermeasure is initiated. For the countermeasure, two control interventions are available, which can be carried out individually as alternatives or together in combination.

[0068] Step S7a: A first control intervention consists in changing the actuating speed s(t) of the sliding sleeve 7 and therefore the duration of the actuation t until the engagement in such a way that the result is a new engagement time t.sub.1 of the sliding sleeve 7 at which the desired target rotational angle position .sub.soll is achieved.

[0069] Step S7b: A second control intervention consists in changing the rotational speed n.sub.1 of the sliding sleeve 7 by way of the engine control unit 5a, which brings about the desired relative target rotational angle position .sub.soll at the original or at the new engagement time t.sub.1.

[0070] Step S8: When the target rotational angle position .sub.sol is reached at the original or at the new engagement time t.sub.1, the sets of dog teeth 10, 13 are engaged and finally a following step, namely: step S9 is carried out, with: complete engagement of the dog clutch 6 until the end position s.sub.2 of the sliding sleeve movement for switching the gear is reached at an end time t.sub.2.Math. after an overall shorter actuating time period t*.

LIST OF REFERENCE SYMBOLS (CONSTITUENT PART OF THE DESCRIPTION)

[0071] 1 Vehicle, commercial vehicle [0072] 2 Manual transmission [0073] 3 Input shaft [0074] 4 Output shaft [0075] 4a Cardan shaft [0076] 5 Electric drive machine [0077] 5a Engine control unit [0078] 6 Dog clutch [0079] 7 Sliding sleeve [0080] 8 Driver toothing of the sliding sleeve [0081] 9 Main body of the sliding sleeve [0082] 10 Dog teeth on the sliding sleeve [0083] 11 Idler gear of a forward gear [0084] 12 Coupling element of the idler gear [0085] 13 Dog teeth on the coupling element [0086] 14 Guide groove of the sliding sleeve [0087] 15 Switching element, selector fork [0088] 16 Electric actuator [0089] 17 Device for actuating a dog clutch [0090] 18 Sensor device [0091] 19 Sensor of the sensor device [0092] 20 Electronic control device [0093] 21 Differential gearbox [0094] 22a First rear axle drive shaft [0095] 22b Second rear axle drive shaft [0096] 23a First front wheel [0097] 23b Second front wheel [0098] 24a First rear wheel [0099] 24b Second rear wheel [0100] 25 Linear actuating speed curve [0101] 26 Non-linear actuating speed curve [0102] 27 Idler gear of a reverse gear [0103] 28 Arrow, measured values [0104] G1 First gear of the manual transmission [0105] RG Reverse gear of the manual transmission [0106] S Position of the sliding sleeve [0107] So Neutral position of the sliding sleeve [0108] s.sub.1 Engagement position of the sliding sleeve [0109] s.sub.2 End position of the sliding sleeve [0110] s(t) Actuating speed of the sliding sleeve [0111] s Actuating travel of the sliding sleeve [0112] K.sub.1 Contour of the first set of dog teeth [0113] K.sub.2 Contour of the second set of dog teeth [0114] n.sub.1 Rotational speed of the sliding sleeve [0115] n.sub.2 Rotational speed of the idler gear of the first gear [0116] t Time [0117] t.sub.0 Actuation time [0118] t.sub.1 Engagement time [0119] t.sub.2 End time of the sliding sleeve movement [0120] t.sub.2 Earlier end time of the sliding sleeve movement [0121] t Longer actuating time period [0122] t* Shorter actuating time period [0123] .sub.1 Rotational angle position of the sliding sleeve [0124] .sub.2 Rotational angle position of the idler gear of the first gear [0125] .sub.soll Relative rotational angle position of the two sets of dog teeth relative to each other [0126] S1-S9 Method steps