Transmission for a motor vehicle, especially for a motorcycle

Abstract

Transmission (1) for a motor vehicle, with at least one rotatable shift drum (4), by means of which gears of the transmission (1) can be engaged and disengaged by rotating the shift drum (4), characterized by: - ​​at least one Maltese cross transmission (6), which has at least one star gear (7) with at least one groove (8) and at least one drive gear (10) having a shift bolt (11) and rotatable about an axis of rotation (12), which is translationally movable along the axis of rotation (12) relative to the star gear (7) between at least one actuation position, in which, upon a complete revolution of the drive gear (10) about the axis of rotation (12), the shift bolt (11) can be brought into engagement with the groove (8) of the star gear (7), thereby effecting a rotation of the star gear (7), and at least one decoupling position (E),in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the switching bolt (11) does not engage in the groove (8) and thus the star wheel (7) is not rotated by the drive wheel (10), whereby rotation of the switching drum (4) can be effected by rotating the star wheel (7); - a sliding cam (15) provided on the drive wheel (10); - at least one actuator (16); and- at least one pin (17) which, by means of the actuator (16), can be moved relative to the drive wheel (10) from at least one initial position (A), in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the pin (17) does not engage with the sliding cam (15) and thus a movement of the drive wheel (10) from the decoupling position (E) to the actuating position caused by the pin (17) and the sliding cam (15) does not occur, into at least one engagement position,in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the pin (17) can be brought into engagement with the sliding cam (15), thereby enabling a movement of the drive wheel (10) from the decoupling position (E) to the actuating position.

Description

The invention relates to a transmission for a motor vehicle, in particular for a motorcycle, according to the preamble of claim 1.DE 10 2014 200 829 A1 discloses a transmission for a vehicle, in particular for a motorcycle. The transmission has a drive shaft that rotates about a drive axis and an output shaft arranged parallel to the drive shaft. In addition, a radiation source for emitting electromagnetic radiation is provided. The transmission further comprises a radiation detector for detecting the radiation emitted by the radiation source.Furthermore, DE 10 2005 003 079 A1 discloses an internal combustion engine having a valve train in which functions on the valve train are actuated by at least two actuating elements which are connected to the housing of the internal combustion engine.Furthermore, U.S. Pat. No. 5,395,293 A discloses a transmission for a motor vehicle, wherein the transmission has a Maltese cross transmission.DE 32 263 11 A1 discloses a step-by-step transmission for the spindle drum of a multi-spindle lathe.WO 1997 / 002 963 A2 discloses a clutch and transmission actuation device.It is the object of the present invention to provide a transmission for a motor vehicle, so that an automated shifting of the transmission at a high shifting speed can be realized in a particularly simple manner.This object is achieved according to the invention by a transmission having the features of claim 1. Advantageous embodiments of the invention are the subject of the dependent claims.The transmission according to the invention for a motor vehicle, in particular for a motorcycle, has at least one rotatable shift drum, by means of which gears of the transmission can be engaged and disengaged by rotating the shift drum. The shift drum can have guide grooves for pins provided on shift forks. The respective pin thus engages, for example, in the respective guide groove. If the shift drum is rotated, the shift forks and shift sleeves of the transmission are thereby moved via the shift forks, wherein the gears of the transmission can be engaged and disengaged by moving the shift forks and the shift sleeves. For example, by stepwise rotation of the shift drum, for example, an initially engaged one of the gears can be disengaged and an initially disengaged further one of the gears can be engaged.In order to be able to realize an automated shifting of the transmission, which is designed as a shift transmission, for example, at a high shifting speed in a particularly simple and thus cost-effective manner, in particular with a very low construction outlay, it is provided according to the invention that the transmission comprises at least one Maltese cross transmission. The Maltese cross gear has at least one starwheel, also referred to as a Maltese cross, with at least one groove which preferably extends in a straight or linear manner. The groove is a recess of the starwheel. The starwheel is a rotatable wheel or a rotatable disc and has the groove, wherein the starwheel can have the shape of a Maltese cross. The starwheel is referred to in particular as a starwheel because, for example, the groove extends, in particular linearly, in the radial direction of the starwheel like a beam of a starwheel.The Maltese cross gear moreover has at least one drive wheel which can rotate about an axis of rotation and which has a switching bolt. Thus, the switching pin and the drive wheel are rotatable jointly or simultaneously about the axis of rotation. In other words, the switching pin can be rotated together with the drive wheel about the axis of rotation. The drive wheel and thus the switching pin can be moved in translation, i.e. displaced, along the axis of rotation relative to the starwheel between at least one actuation position and at least one decoupling position. In the actuation position, the switching pin engages with the groove of the starwheel during a complete rotation of the drive wheel about the axis of rotation. In other words, the drive wheel and thus the switching pin are in the actuating position, and during this time, if the drive wheel and thus the switching pin are rotated about the axis of rotation in such a way that the drive wheel and the switching pin execute at least one complete revolution about the axis of rotation, the switching pin engages with the groove during this complete revolution. In other words, the switching bolt engages in the groove, so that the switching bolt cooperates with the starwheel in a positive-locking manner, for example. Engagement of the switching pin in the groove of the starwheel and rotation of the drive wheel about the axis of rotation result in rotation of the starwheel, in particular in a first direction of rotation. This means that, due to the drive wheel being rotated about the axis of rotation and during which the switching bolt engages in the groove, the drive wheel drives the star wheel with it, so that the star wheel is rotated, in particular in the first direction of rotation.In the decoupling position, however, an engagement of the switching bolt in the groove and thus a rotation of the starwheel effected by the drive wheel do not occur during a complete rotation of the drive wheel and thus of the switching bolt about the axis of rotation. In other words, if the drive wheel and thus the switching pin are in the decoupling position, and if, during this, the drive wheel and the switching pin are completely rotated about the axis of rotation at least once, such that the drive wheel and the switching pin execute at least one complete rotation about the axis of rotation while they are in the decoupling position, the switching pin does not engage with the groove, such that a rotation of the starwheel caused by the drive wheel and the switching pin does not occur, even though the drive wheel is rotated about the axis of rotation.In this case, a rotation of the shift drum can be effected by rotating the starwheel. In other words, the shift drum can be driven by the starwheel and can thereby be rotated, so that the shift drum can be rotated by rotation of the starwheel. Since gears of the transmission can be engaged and disengaged by rotating the shift drum, engaging and / or disengaging at least one of the gears of the transmission can be effected by rotating the starwheel.The transmission additionally comprises a sliding gate provided on the drive wheel and thus co-rotatable with the drive wheel. Furthermore, the transmission comprises an actuator which can be operated or actuated, for example, pneumatically and / or electrically and / or hydraulically. In addition, the transmission comprises at least one pin, also referred to as a pin, an actuating pin or an actuating pin, which is movable by means of the actuator relative to the drive wheel and in this case obliquely or perpendicularly to the axis of rotation or in the radial direction of the drive wheel from at least one starting position into at least one engagement position. In the initial position, an engagement of the pin in the sliding gate and thus a movement of the drive wheel from the decoupling position into the actuation position brought about by the pin in the sliding gate are omitted in the case of a complete rotation of the drive wheel about the axis of rotation. In other words, if the pin is in the starting position, the pin does not engage in the sliding gate, even if the drive wheel and thus the sliding gate are rotated completely about the axis of rotation at least once or several times. Thus, there is also no movement or displacement of the drive wheel from the decoupling position into the actuation position when the pin is in the starting position and the drive wheel is rotated about the axis of rotation.In the engagement position, however, during a complete rotation of the drive wheel about the axis of rotation, the pin engages with the sliding gate, resulting in a movement, in particular displacement, of the drive wheel and of the switching pin, effected by means of the pin and the sliding gate from the decoupling position into the actuation position. Overall, it can be seen that a rotation of the starwheel and a rotation of the shift drum resulting therefrom can be effected in that the pin is moved by means of the actuator from the starting position into the engagement position. However, if the pin does not move from the starting position into the engagement position, i.e. if the pin is not moved from the starting position into the engagement position, the starwheel and the shift drum do not rotate by means of the drive wheel.The invention makes it possible to keep an additional construction outlay particularly low in the case of a transmission which is to be newly constructed. At the same time, the invention enables the realization of an automated shifting of the transmission at a high shifting speed. In this case, components which are already known per se are used, as a result of which the costs can be kept low and a particularly high degree of robustness can be realized.The actuator, also referred to as actuator, and the pin, also referred to as pin, form, for example, a so-called one-pin actuator, which is already known from valve drives, for example. By means of the pin and the sliding gate, a rotation of the drive wheel running about the axis of rotation can be brought about in a displacement of the drive wheel running along the axis of rotation, in particular from the decoupling position into the actuation position, in particular in that the pin engages in the sliding gate while the drive wheel rotates about the axis of rotation. The sliding gate is formed or limited, for example, along the axis of rotation or in the axial direction of the drive wheel by respective side walls and in a direction running obliquely or perpendicular to the axis of rotation or in the inward radial direction of the drive wheel by a base. The side walls are spaced apart from one another, for example, along the axis of rotation. At least one of the side walls extends in a plane which extends obliquely to the axis of rotation, in particular in such a way that a projection of the at least one side wall onto a plane in which the axis of rotation extends extends obliquely to the axis of rotation. If the drive wheel is thus rotated about the axis of rotation while the pin engages in the sliding gate, the pin comes into supporting contact with the obliquely running side wall. If the drive wheel and the sliding gate are then rotated further, the pin slides off the obliquely running side wall or vice versa, so that a force running along the axis of rotation acts from the pin on the side wall. By means of this force, the drive wheel and the sliding gate are displaced, in particular from the decoupling position into the coupling position. In other words, the supporting contact of the pin with the obliquely running side wall results in a force running along the axis of rotation, by means of which the drive wheel is displaceable or is displaced from the decoupling position into the actuating position. In this way, the drive wheel and the switching pin can be displaced in a particularly simple, space-saving and cost-effective manner. As a result, the switching pin engages in the groove of the starwheel, whereby the starwheel and as a result the drive roller are rotated. This allows a very compact construction of the transmission to be realized and at the same time a particularly high shifting speed to be ensured.By means of the invention, a transmission, which is designed, for example, as a transmission or manual transmission, can be further developed to form an automated transmission, so that the transmission according to the invention is preferably designed as an automated transmission. Conventional automated manual transmissions have an actuator with an electric motor which directly rotates the shift drum or indirectly prestresses a spring store which then rotates the shift drum. Such electromotive actuators require a large amount of installation space, so that their arrangement is very difficult and is usually not possible, in particular in the case of a motorcycle. Supplying such an electromotive actuator with electric current is very burdensome for an on-board power supply of the motor vehicle, in particular when high switching dynamics are required, in particular with regard to a peak current. In addition, an electronic control unit must be able to switch large currents, so that high costs and a high weight of such an electronic control unit also occur. The aforementioned problems and disadvantages can be avoided by means of the transmission according to the invention, since, for example, an energy required for moving the pin, with which energy the actuator is to be supplied in order to move the pin, can be kept particularly low.It has been found to be particularly advantageous if the starwheel is coupled, in particular mechanically, to the shift drum via a spring element which is designed, for example, as a torsion spring and which permits a relative rotation between the starwheel and the shift drum under the tension of the spring element. As a result, for example, when a rotation of the shift drum is not possible, a movement of the pin from the starting position into the engagement position and a displacement of the drive wheel from the decoupling position into the actuation position and an engagement of the shift bolt into the groove and a rotation of the starwheel can be permitted without excessive loads, damage or destruction of the transmission occurring. In such a case, the starwheel is simply rotated relative to the shift drum, thereby tensioning the spring element. If the drive wheel and the switching bolt are then rotated further to such an extent that the switching bolt is moved out of the groove again, then the starwheel is rotated back into a starting position by means of the tensioned spring element or by means of a spring force provided by the tensioned spring element, for example. A rotation of the shift drum can be avoided, for example, by a so-called claw-claw hit of wheels in a main transmission of the transmission, that is to say, for example, when at least one of the shift forks or at least one of the shift sleeves cannot be displaced and consequently the shift drum cannot be rotated.A further embodiment is distinguished by a fixing device by means of which the shift roller is to be secured against rotation. As a result, undefined rotational positions of the shift drum and of the starwheel can be avoided, for example, so that undesired shifting processes and excessive loads can be avoided in a simple, space-saving and cost-effective manner.In a further embodiment of the invention, the transmission comprises a return spring which is tensioned at least in the actuation position and thereby provides a spring force, by means of which the drive wheel and thus the shift bolt can be moved or displaced from the actuation position into the decoupling position. As a result, a return of the switching bolt and the drive wheel from the actuation position into the decoupling position can be realized in a simple, construction-space-efficient and cost-effective manner.In a further embodiment of the invention, the sliding gate, in particular its base, is designed to bring about a movement of the pin from the engagement position into the starting position during a complete rotation of the drive wheel about the axis of rotation. This makes it possible to avoid space-intensive, cost-intensive and weight-intensive return mechanisms for moving the pin from the engagement position into the starting position.For this purpose, the base is formed, for example, in such a way that it extends in the circumferential direction of the drive wheel and in the radial direction from the outside to the inside. As a result, for example, the pin initially located in the engagement position comes into supporting contact with the ground during a rotation of the sliding gate. During a further rotation of the sliding gate, the pin slides on the floor. Since the bottom extends in the circumferential direction of the drive wheel and from the inside to the outside in the radial direction, the pin is pressed from the inside to the outside in the radial direction of the drive wheel by means of the bottom and is thereby shifted, for example, from the engagement position into the starting position.In order to keep the installation space requirement and thus the costs and the weight of the transmission particularly low and at the same time to be able to realize very high shift speeds, it is provided in a further embodiment of the invention that the drive wheel is mechanically coupled to an output shaft, which is designed for example as a crankshaft, of a drive motor of the motor vehicle, which drive motor is designed for example as an internal combustion engine, and can thereby be mechanically driven by the drive shaft.It has been found to be particularly advantageous if the drive wheel meshes with a gear wheel that can be driven mechanically by the drive shaft. This allows particularly short switching times to be realized in a cost-effective manner. The motor vehicle has, for example, the drive motor in its completely produced state, wherein the motor vehicle can be driven by means of the drive motor.Alternatively or additionally, it is possible for the drive wheel to be drivable by means of a drive provided in addition to the drive motor. The drive can be operated, for example, by a motor and / or electrically and / or pneumatically and / or hydraulically. In order to be able to keep the installation space requirement of the drive particularly low, it is preferably provided that at least one flywheel mass is arranged in the torque and / or force flow between the drive and the drive wheel with respect to a torque and / or force flow running from the drive to the drive wheel, so that, for example, the drive wheel can be driven by the drive via the flywheel mass.In order to be able to realize a particularly advantageous shiftability of the transmission in a manner which is particularly advantageous in terms of space saving, the Maltese cross transmission in a further embodiment of the invention has a second drive wheel which has a second shift bolt and is rotatable about a second axis of rotation.The second axis of rotation can coincide with the first axis of rotation, or else the axes of rotation are off-axis from one another and thus run parallel to one another. The second drive wheel and thus the second switching pin are displaceable along the second axis of rotation relative to the starwheel between at least one second actuation position and at least one second decoupling position. In the actuation position, during a complete rotation of the second drive wheel about the second axis of rotation, the second switching pin engages with the groove of the starwheel, resulting in a rotation of the starwheel. In the decoupling position, during a complete rotation of the second drive wheel about the second axis of rotation, the second switching pin does not engage in the groove and thus a rotation of the starwheel effected by the second drive wheel.In this case, a second sliding gate is provided on the second drive wheel, and a second actuator and a second pin are also provided. The second pin is movable, in particular translationally displaceable, by means of the second actuator relative to the drive wheels from a second starting position into a second engagement position. The preceding and following embodiments relating to the first drive wheel, the first pin, the first actuator and the first switching pin can also be easily transferred to the second drive wheel, the second switching pin, the second pin and the second actuator, and vice versa. In the second starting position, an engagement of the second pin in the second displacement gate and thus a movement of the second drive wheel from the second decoupling position into the second actuation position brought about by the second pin and the second displacement gate are omitted in the case of a complete rotation of the second drive wheel about the second axis of rotation. In the second engagement position, however, during a complete rotation of the second drive wheel about the second axis of rotation, the second pin engages with the second sliding gate, resulting in a movement of the second drive wheel and thus of the second switching bolt from the second decoupling position into the second actuation position. Thus, a rotation of the starwheel and a rotation of the shift drum can be effected by moving the second pin from the second initial position to the second engaged position.In order to be able to realize a particularly advantageous shiftability of the transmission in a manner which is advantageous in terms of installation space, it is provided in a further embodiment of the invention that the drive wheels rotate in opposite directions to one another during operation of the transmission, that is to say when the drive wheels rotate about the respective axes of rotation. As a result, a rotation of the starwheel in the first rotational direction can be effected by means of the first drive wheel and by means of the first switching pin, and a rotation of the starwheel in a second rotational direction opposite the first rotational direction can be effected by means of the second drive wheel and by means of the second switching pin. As a result, an upshift of the transmission can be effected, for example, by means of the first drive wheel and by means of the first shift bolt, wherein a downshift of the transmission can be effected, for example, by means of the second drive wheel and by means of the second shift bolt. This can be realized in a particularly space-efficient, weight-efficient and cost-effective manner.Finally, it has been shown to be particularly advantageous if the drive wheels mesh directly with one another, in particular via respective toothings. This makes it possible to realize in a particularly simple manner that the first drive wheel rotates in a first wheel rotational direction, while the second drive wheel rotates in a second wheel rotational direction opposite the first wheel rotational direction. In other words, because the drive wheels mesh directly with one another, a particularly advantageous reversal of the direction of rotation of the second drive wheel relative to the first drive wheel can be realized, so that the number of parts, the costs and the weight can be kept particularly low.Further details of the invention will become apparent from the following description of a preferred exemplary embodiment with the associated drawings. The following shows: FIG. 1 shows a schematic side view of a transmission according to the invention for a motor vehicle, in particular a motorcycle; FIG. 2 shows a schematic front view of a portion of the transmission; and FIG. 3 shows a detail of a further schematic front view of the transmission.In the figures, identical or functionally identical elements are provided with identical reference symbols.FIG. 1 shows a schematic side view of a section of a transmission 1 for a motor vehicle, in particular for a motorcycle. The motor vehicle has, in its completely produced state, the transmission 1 and at least or exactly one drive motor, by means of which the motor vehicle can be driven via the transmission 1. In particular, at least or exactly one wheel of the motor vehicle can be driven by the drive motor via the transmission 1. For this purpose, the drive motor has an output shaft, which is designed, for example, as a crankshaft and via which the drive motor can provide torques for driving the motor vehicle or the wheel. The drive motor is also referred to as a motor and is designed, for example, as an internal combustion engine, which is also referred to as an internal combustion engine. In particular, the internal combustion engine can be designed as a reciprocating piston engine or reciprocating piston engine.The motorcycle is also referred to as a motorcycle and is, for example, a single-track motor vehicle which has exactly two wheels arranged one behind the other in the longitudinal direction of the vehicle. As will be explained in more detail below, the transmission 1 can be designed as an automated transmission. The transmission 1 has a housing 2 which is illustrated particularly schematically and only in a detail in FIG. 1 and is also referred to as a transmission housing. The transmission housing delimits or forms a receiving space 3, in which transmission elements of the transmission 1 can be accommodated.The transmission 1 furthermore comprises at least or exactly one shift drum 4, which is rotatable relative to the housing 2 about an axis of rotation 5, also referred to as shift drum axis of rotation. By rotating the shift drum 4 about the axis of rotation 5 relative to the housing 2, gears of the transmission 1 can be engaged and disengaged. For this purpose, the shift drum 4 has grooves, not shown in FIG. 1, in which pins of shift forks engage, for example. By rotating the shift drum 4 about the axis of rotation 5 relative to the housing 2, the shift forks can be displaced, in particular relative to the housing 2, so that respective shift muffles, in particular relative to the housing 2, can be displaced by means of the shift forks. As a result, the gears of the transmission 1 can be engaged and disengaged.In order to be able to realize an automated shifting of the transmission 1 at high shifting speeds in a manner which is particularly cost-effective and space-efficient, the transmission 1 has a Maltese cross transmission 6. The Maltese cross-gear 6 can be seen particularly well when viewed together with FIG. 2. The Maltese cross gear 6 has at least or exactly one star wheel 7, which has a plurality of grooves 8 spaced apart from one another in the circumferential direction of the star wheel 7 and also referred to as recesses. The grooves 8 are formed in the present case as through-openings which completely penetrate the star wheel 7 in the axial direction of the star wheel 7. In particular, the respective groove 8 is a slot which is bounded inward in the radial direction of the starwheel 7 and is bounded outward in the radial direction of the starwheel 7. In other words, the respective groove in the radial direction of the starwheel 7 towards the outside is not bounded by a wall region of the starwheel 7. The grooves 8 are arranged uniformly distributed in the circumferential direction of the starwheel 7. In addition, the respective groove 8 has a straight or linear course which runs in the radial direction of the starwheel 7. The starwheel 7 is rotatable relative to the housing 2 about an axis of rotation 9 which coincides with the axis of rotation 5 and is also referred to as the starwheel axis of rotation.The Maltese cross transmission 6 furthermore has a first drive wheel 10 which has at least or exactly one first shift bolt 11. The drive wheel 10 is rotatable relative to the housing 2 about an axis of rotation 12, also referred to as the drive wheel axis of rotation or first drive wheel axis of rotation, wherein the axis of rotation 12 is arranged off-axis to the axes of rotation 5 and 9 and thus runs parallel to the axes of rotation 5 and 9. In other words, the rotation axis 12 does not coincide with the rotation axes 5 and 9. The drive wheel 10 and thus the switching pin 11 are translationally movable along the axis of rotation 12 relative to the starwheel 7 between at least one decoupling position E shown in FIG. 1 and at least one actuating position not shown in the figures along the axis of rotation 12 and are thus displaceable. This means that the drive wheel 10 is displaceable relative to the starwheel 7 between the decoupling position E and the actuation position along a displacement direction which coincides with the axis of rotation 12 and is illustrated in FIG. 1 by a double arrow 13.In the following, one of the grooves 8 is denoted by N 1 in order to be able to unambiguously distinguish the groove N 1 from the other remaining grooves 8. If the drive wheel 10 and the switching pin 11 are in the decoupling position E, while the drive wheel 10 is rotated about the axis of rotation 12 relative to the housing 2, the switching pin 11 does not engage with the grooves 8 of the starwheel 7, so that no interaction of the switching pin 11 with the starwheel 7 is obtained. As a result, the starwheel 7 is not rotated by means of the shift bolt 11. In other words, during a complete rotation of the drive wheel 10 about the axis of rotation 12, the switching pin 11 does not engage in the respective groove 8 and thus a rotation of the starwheel 7 effected by the drive wheel 10.However, if the drive wheel 10 and thus the switching pin 11 are in the actuation position, while the drive wheel 10 and thus the switching pin 11 are rotated about the axis of rotation 12, in particular in such a way that the drive wheel 10 and thus the switching pin 11 are rotated at least a complete time about the axis of rotation 12, the switching pin 11 comes into engagement with the groove N 1, for example. The switching pin 11 thus interacts in a form-fitting manner with the starwheel 7 such that the starwheel 7 is rotated about the axis of rotation 9 in a first direction of rotation 14 illustrated by an arrow in FIG. 2. In other words, in the actuating position, during a complete rotation of the drive wheel 10 about the axis of rotation 12, the switching pin 11 engages with one of the grooves 8, for example with the groove N 1, resulting in a rotation of the starwheel 7 about the axis of rotation 9 in the first direction of rotation. If a rotation of the shift drum 4 about the axis of rotation 5 is not prevented or prevented, then the shift drum 4 is rotated about the axis of rotation 5 relative to the housing 2 in the first direction of rotation by rotating the starwheel 7 in the first direction of rotation, whereby, for example, an initially engaged first of the gears is disengaged and an initially disengaged second of the gears is engaged.In order to be able to realize the displacement of the drive wheel 10 along the axis of rotation 12 and consequently a rotation of the star wheel 7 in a particularly simple manner which is cost-effective and space-effective, a displacement gate 15 provided on the drive wheel 10, an actuator 16 and a pin 17 also referred to as a pin are provided. The pin 17 is movable by means of the actuator 16 in translation relative to the housing 2 along a direction of movement illustrated in FIG. 1 by a double arrow 18 from an initial position A shown in FIG. 1 into an engagement position not shown in the figures. The direction of movement illustrated by the double arrow 18 extends obliquely or in the present case perpendicularly to the axis of rotation 12.In the initial position A, even in the case of a complete rotation of the drive wheel 10 about the axis of rotation 12, the pin 17 does not engage in the displacement gate 15 and thus a translatory movement of the drive wheel 10 from the decoupling position E into the actuation position brought about by the pin 17 and the displacement gate 15. In other words, if the pin 17 is in the starting position A, while the drive wheel 10 is moved completely about the axis of rotation 12 relative to the housing 2 at least once or several times, the pin 17 does not engage with the sliding gate 15, so that the drive wheel 10 is not displaced, in particular not from the decoupling position E into the actuation position.In the engagement position, however, during a complete rotation of the drive wheel 10 about the axis of rotation 12, the pin 17 engages with the sliding gate 15, resulting in a movement of the drive wheel 10 from the decoupling position E into the actuation position. In other words, if the pin 17 is in the engagement position, while the drive wheel 10 and thus the switching pin 11 are completely rotated about the axis of rotation 12 at least once or several times, the pin 17 comes into engagement with the sliding gate 15, so that the pin 17 and the sliding gate 15 convert the rotation of the drive wheel 10 about the axis of rotation 12 into a translatory movement of the drive wheel 10 from the decoupling position E into the actuation position. For this purpose, at least one wall region 19 of a side wall 20 of the sliding gate 15 runs obliquely to a drive wheel rotational direction, in which the drive wheel 10 is rotated about the rotational axis 12 during operation of the transmission 1. Thus, when the drive wheel 10 is rotated in the drive wheel rotation direction about the rotation axis 12 relative to the housing 2, the pin 17 located in the engaged position comes into abutment with the wall portion 19, and as a result, the wall portion 19 slides off the pin 17, resulting in a force acting on the drive wheel 10 and running along the rotation axis 12. The force points, for example, in the direction of the switching bolt 11, so that the drive wheel 10 is displaced from the decoupling position E into the actuation position. Overall, it can be seen that a rotation of the starwheel 7 in the first direction of rotation can be effected in a particularly simple, space-saving, weight-saving and cost-effective manner by the pin 17 being moved by means of the actuator 16 from the starting position A into the engagement position.The starwheel 7 is coupled to the shift drum 4 via a spring element which is also referred to as a decoupling spring and which, under the tension of the spring element 21, permits a relative rotation between the starwheel 7, which is also referred to as a Maltese cross, and the shift drum 4. If, for example, the pin 17 is moved from the starting position A into the engagement position while the shift drum 4 is secured against rotation in the first rotational direction relative to the housing 2, the Maltese cross can nevertheless be rotated in the first rotational direction relative to the shift drum 4, since this is permitted by the spring element 21. As a result, the spring element 21 is tensioned. If the switching bolt 11 moves out of the groove N 1 again, the spring element 21 can at least partially be relaxed. As a result, the Maltese cross is rotated in a second rotational direction 22, illustrated by an arrow in FIG. 2 and opposite the first rotational direction, so that the Maltese cross is rotated back. If the Maltese cross is rotated in the first direction of rotation by means of the switching bolt 11 in the described manner, the Maltese cross is thereby rotated, for example, from a first position shown in FIG. 2 into a second position, wherein the Maltese cross is rotated, for example, by at least or exactly 60 degrees. If the shift drum 4 is secured against co-rotation with the Maltese cross so that the spring element 21 is tensioned, then the Maltese cross is rotated back from the second position into the first position by relaxing the spring element 21.If, however, the shift drum 4 is not secured against rotation, the shift drum 4 is rotated together with the Maltese cross, in particular via the spring element 21. Thus, the fixing element 23 can also be rotated about the axis of rotation 5 or 9 with the shift drum 4. Via the fixing element 23, the switching roller 4 can be driven by the Maltese cross and thus rotated about the axis of rotation 5.The fixing element 23 has successive recesses 24 in the circumferential direction of the fixing element 23. The fixing element 23 is part of a fixing device 25 which comprises the fixing element 23 and a further fixing element in the present case in the form of a locking lever 26. The locking lever 26 is held at least indirectly, in particular directly, pivotably on the housing 2 and is supported on the housing 2 for example via a spring element 27. The locking lever 26 can engage in the respective recess 24 of the fixing element 23, as a result of which the fixing element 23 can interact with the locking lever 26 in a positive-locking manner. As a result, the fixing element 23 and, via the latter, the shift drum 4 are secured against undesired rotations relative to the housing 2 about the axis of rotation 5.The transmission 1 furthermore has a return spring 28 which can be seen particularly well from FIG. 1 and which is supported on the one hand at least indirectly, in particular directly, on the drive wheel 10 and on the other hand, for example at least indirectly, in particular directly, on the housing 2. By moving the drive wheel 10 from the decoupling position E into the actuation position, the return spring 28 is tensioned, in particular compressed, so that the return spring 28 provides a spring force at least in the actuation position. The drive wheel 10 is held in the actuation position, for example, counter to the spring force provided by the return spring 28, in that the pin 17 engages in the sliding gate 15. Alternatively or additionally, the switching bolt 11 has a collar 29. If the drive wheel 10 is rotated with the switching pin 11 while the drive wheel 10 is in the actuation position, the switching pin 11 that can be seen particularly well from FIG. 2 is moved along its radial direction and in the process in the radial direction of the Maltese cross from the outside inward into the respective groove 8, for example into the groove N 1. Then, for example, the collar 29 engages behind the Maltese cross or at least one wall region of the Maltese cross at least partially delimiting the groove N 1, whereby the collar 29 is or is supported along its axial direction and in the process in the direction of the drive wheel 10 on the Maltese cross. As a result, for example, the drive wheel 10 is held in the actuating position counter to the spring force provided by the return spring 28.After the Maltese cross has been rotated into the second position, the switching pin 11 is moved out of the groove N 1 from the inside outwards by further rotation of the drive wheel 10 in the radial direction of the Maltese cross. As a result, the switching bolt 11 no longer positively interacts with the Maltese cross and the return spring 28 can at least partially tension. As a result, the drive wheel 10 is moved back from the actuation position into the decoupling position E by means of the spring force provided by the return spring 28. If the drive wheel 10 is then moved again from the decoupling position E into the actuation position, for example, the switching bolt 11 can then engage in the correspondingly next one of the grooves 8 and so on. This next groove is denoted in FIG. 2 by N2, for example.The sliding gate 15 preferably has a base 30, which extends at least in a partial region in the radial direction of the drive wheel 10 from the inside to the outside. The pin 17 initially located in the engagement position can thus come into supporting contact with the mentioned partial region of the base 30, so that the pin 17 slides off the partial region. This results in a force pointing in the direction of the actuator 16 and acting on the pin 17, by means of which the pin 17 is displaced from the engagement position back into the starting position A.It can be seen particularly well from FIGS. 1 and 2 that the drive wheel 10 is designed as a gearwheel which has a toothing 31, in particular in the form of an external toothing. In this case, the transmission 1 additionally comprises a further gearwheel 32 which can be driven mechanically by the output shaft and which has a further toothing 33. The tooth arrangements 31 and 33 are in engagement with one another, so that the drive wheel 10 meshes with the gearwheel 32. As a result, the drive wheel 10 can be mechanically driven by the output shaft via the gearwheel 32, with the result that particularly high switching times can be realized in a manner which is cost-effective and space-saving.In order to be able to rotate the Maltese cross both in the first rotational direction and in the second rotational direction, as a result of which, for example after a shift from the first gear into the second gear, it is possible to shift immediately from the second gear back into the first gear again, the Maltese cross transmission 6 comprises a second drive wheel 34 which has a second shift bolt 35. The above and following embodiments relating to the drive wheel 10 and the shift bolt 11 can also be easily transferred to the drive wheel 34 and the shift bolt 35. The drive wheel 34 is rotatable relative to the housing 2 about a second axis of rotation 36, also referred to as a second axis of rotation of the drive wheel, wherein the axes of rotation 12 and 36 are spaced apart from one another or are de-aligned from one another and run parallel to one another. The drive wheel 34 and with it the switching bolt 35 can be moved translationally, i.e. displaced, relative to the housing 2 along the axis of rotation 36 between a second actuation position and a second decoupling position. In the second actuation position, during a complete rotation of the second drive wheel 34, the second switching bolt 35 engages with the respective groove 8 of the Maltese cross, resulting in a rotation of the Maltese cross in the second rotational direction. In the second decoupling position, however, an engagement of the second switching pin 35 in the respective groove 8 and thus a rotation of the Maltese cross (star wheel 7) effected by the second drive wheel 34 are omitted even in the case of a complete rotation of the second drive wheel 34 about the second axis of rotation 36.If, for example, the Maltese cross is in the first position shown in FIG. 2, and if the drive wheel 34 and thus the switching bolt 35 are rotated about the axis of rotation 36 relative to the housing 2, while the drive wheel 34 and the switching bolt 35 are in the second actuation position, the switching bolt 35 comes into engagement with the groove N 2. As a result, the starwheel 7 is rotated in the second direction of rotation, in particular by 60 degrees, whereby, for example, the Maltese cross is rotated from the first position shown in FIG. 2 into a second position.In the described manner, the Maltese cross can be rotated in the first rotational direction, for example by means of the drive wheel 10, until the Maltese cross assumes such a position in which the switching bolt 35 can engage in the groove N 1 when the drive wheel 34 is in the second actuation position. The same applies to the groove N 2 with respect to the shift pin 11. In particular, it can be seen that the Maltese cross can be rotated by means of the drive wheels 10 and 34 particularly according to requirements and in a manner that is simple in terms of installation space, weight and cost-effective in the first direction of rotation and in the second direction of rotation, in order thereby to be able to rotate the shift drum 4 according to requirements in the first direction of rotation and in the opposite second direction of rotation.During the above-described operation of the transmission 1, the drive wheel 10 rotates about the rotation axis 12 in the aforementioned first rotational direction, for example. the drive wheel 34 rotates in the opposite direction to the drive wheel 10, so that, for example, the drive wheel 34 rotates in a second rotational direction of the drive wheel opposite to the first rotational direction. For this purpose, it is provided, for example, that the drive wheel 34 is also designed as a gearwheel which has a toothing 37 designed, in particular, as an external toothing. In this case, for example, the drive wheels 10 and 34 mesh directly with one another via their tooth arrangements 31 and 37.The respective drive wheel 10 or 34 and thus the respective switching bolt 11 or 35 are rotatable about the rotational axis 12 or 36 and are thereby movable into different rotational positions or rotational positions. In this case, for example, a position sensor 39 is provided, by means of which at least one of the rotational positions of the drive wheel 34 or of the switching bolt 35 can be detected. Alternatively or additionally, a position sensor, not shown in the figures, is assigned to the drive wheel 10, by means of which at least one of the rotational positions of the drive wheel 10 or of the switching bolt 11 can be detected.A shifting process of the transmission 1 is described below, wherein, for example, the Maltese cross is rotated from the first position into the second position within the scope of the shifting process. The starting position is that the internal combustion engine is running, as a result of which, for example, the gearwheel 32 rotates in a gearwheel rotational direction illustrated by an arrow 38 in FIG. 2, the drive wheel 10 rotates in the first drive wheel rotational direction and the drive wheel 34 rotates in the second drive wheel rotational direction. For example, the first gear is engaged and the shift drum 4 is held in place by means of the locking star (fixing element 23) and by means of the spring-loaded locking lever 26, i.e. secured against rotation relative to the housing 2 and thereby held, for example, in a rotational position shown in FIGS. 2 and 1. A shift request of the driver of the motor vehicle activates the actuator 16 designed as a one-pin actuator. The shift request is triggered, for example, by the driver actuating an operating element designed, for example, as a rocker, for example, as a rocker switch, and thereby moving, in particular pivoting, from a first position into a second position, for example. The operating element is arranged, for example, on a steering handle of the motor vehicle, which steering handle is in particular designed as a steering wheel or steering wheel. By activating the actuator 16, the pin 17 is moved by means of the actuator 16 from the starting position A into the engagement position, whereby the pin 17 is moved into the sliding gate 15, also referred to as sliding groove, of the drive wheel 10. As a result, the drive wheel 10 is displaced during its rotation so far along the axis of rotation 12 that the drive wheel 10 comes from the decoupling position E into the actuation position. As a result, the switching pin 11 engages in the groove N1 of the Maltese cross as the drive wheel 10 continues to rotate. When the drive wheel 10 continues to rotate, the pin 17 is pushed back by the displacement link 15, in particular by its contour or by its base 30, and is thus displaced back into the starting position A, and the drive wheel 10 is held by the collar 29 of the shift bolt 11 on or in the Maltese cross of the Maltese cross transmission 6. After the Maltese cross and with it for example the shift drum 4 have rotated in the first direction of rotation for example by 60 degrees, the shift pin 11 leaves the groove N 1 of the Maltese cross and the drive wheel 10 is moved back with the shift pin 11 and the sliding gate 15 by means of the return spring 28 into the decoupling position E. After a corresponding rotation of the shift drum 4, the latter is retained again by means of the retaining star and by means of the retaining lever 26, that is to say secured relative to the housing 2, and the shifting process is concluded.If the shift drum 4 cannot be rotated or cannot be rotated completely, for example, due to a claw-claw hit of wheels of a main transmission of the transmission 1, the decoupling spring between the shift drum 4 and the Maltese cross prevents damage to mechanical components, and the shift operation is not carried out, and the shift drum 4 is returned to a clear position or held there again by the locking star and the locking lever 26.By means of the drive wheel 10, the transmission 1 is shifted up, for example. By means of the drive wheel 34, the transmission 1 is shifted back, for example. Both drive wheels 10 and 34 are coupled to each other by their respective wide gear teeth 31 and 37 such that the drive wheels 10 and 34 are engaged with each other via their gear teeth 31 and 37. The toothings 31 and 37 are so wide or so long in the axial direction of the respective drive wheel 10 or 37 that the toothings 31 and 37 remain in engagement with one another even when one of the drive wheels 10 and 34 is in its decoupling position E and the respective other drive wheel 34 or 10 is in its actuation position.List of reference characters1 Transmission 2 Housing 3 Receiving space 4 Shift roller 5 Axis of rotation 6 Maltese cross transmission 7 Starwheel 8 Groove 9 Axis of rotation 10 Drive wheel 11 Shift pin 12 Axis of rotation 13 Double arrow 14 First direction of rotation (arrow for illustration) 15 Sliding gate 16 Actuator 17 Pin 18 Double arrow 19 Wall region 20 Side wall 21 Spring element 22 Second direction of rotation (arrow for illustration) 23 Fixing element 24 Recess 25 Fixing device 26 Locking lever 27 Spring element 28 Return spring 29 Collar 30 Base 31 Toothing 32 Gearwheel 33 Toothing 34 Second drive wheel 35 Second shift pin 36 Second axis of rotation 37 Toothing 38 Arrow 39 Position sensor A Starting position E Decoupling position N 1 Groove N 2 Groove

Claims

Transmission (1) for a motor vehicle, having at least one rotatable shift drum (4) by means of which gears of the transmission (1) can be engaged and disengaged by rotating the shift drum (4), characterized by: - at least one Maltese cross transmission (6) which has at least one starwheel (7) having at least one groove (8) and at least one drive wheel (10) which has a shift pin (11) and is rotatable about an axis of rotation (12) and can be moved translationally along the axis of rotation (12) relative to the starwheel (7) between at least one actuating position in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the shift pin (11) can be brought into engagement with the groove (8) of the starwheel (7), as a result of which a rotation of the starwheel (7) can be effected, and at least one decoupling position (E), in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the switching pin (11) does not engage in the groove (8) and thus a rotation of the starwheel (7) effected by the drive wheel (10), wherein a rotation of the switching roller (4) can be effected by rotating the starwheel (7); a sliding gate (15) provided on the drive wheel (10); at least one actuator (16); and - at least one pin (17), which can be moved by means of the actuator (16) relative to the drive wheel (10) from at least one starting position (A), in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), an engagement of the pin (17) in the sliding gate (15) and thus a movement of the drive wheel (10) from the decoupling position (E) into the actuation position, effected by the pin (17) and the sliding gate (15), into at least one engagement position, in which, during a complete rotation of the drive wheel (10) about the axis of rotation (12), the pin (17) can be brought into engagement with the sliding gate (15), as a result of which a movement of the drive wheel (10) from the decoupling position (E) into the actuation position can be effected.Transmission (1) according to Claim 1, characterized in that the starwheel (7) is coupled to the shift drum (4) via a spring element (21) which, under the tension of the spring element (21), permits a relative rotation between the starwheel (7) and the shift drum (4).Transmission (1) according to Claim 2, characterized bya fixing device (25), by means of which the shift drum (4) can be secured against rotation.Transmission (1) according to one of the preceding claims, characterized bya return spring (28), which is tensioned at least in the actuation position and thereby provides a spring force, by means of which the drive wheel (10) can be moved from the actuation position into the decoupling position (E).Transmission (1) according to one of the preceding claims, characterized in that the sliding gate (15) is designed to bring about a movement of the pin (17) from the engagement position into the starting position (A) during a complete rotation of the drive wheel (10) about the axis of rotation (12).Transmission (1) according to one of the preceding claims, characterized in that the drive wheel (10) is mechanically coupled to an output shaft of a drive motor of the motor vehicle and can thereby be driven mechanically by the output shaft and / or in that the drive wheel (10) can be driven by means of a drive provided in addition to the drive motor.Transmission (1) according to Claim 6, characterized in that the drive wheel (10) meshes with a gearwheel (32) which can be driven mechanically by the output shaft.Transmission (1) according to one of the preceding claims, characterized in that the Maltese cross transmission (6) has a second drive wheel (34) which has a second switching pin (35) and can be rotated about a second axis of rotation (36) and which can be moved in translation along the second axis of rotation (36) relative to the star wheel (7) between at least one second actuating position in which, in the case of a complete rotation of the second drive wheel (34) about the second axis of rotation (36), the second switching pin (35) can be brought into engagement with the groove (8) of the star wheel (7), as a result of which a rotation of the star wheel (7) can be effected, and at least one second decoupling position, in which, during a complete rotation of the second drive wheel (34) about the second axis of rotation (36), the engagement of the second switching pin (35) in the groove (8) and thus a rotation of the starwheel (7) effected by the second drive wheel (34) are omitted, wherein a second sliding gate is provided on the second drive wheel (34), and wherein a second actuator is provided a second pin which is movable by means of the second actuator relative to the drive wheels (10, 34) from a second starting position, in which, during a complete rotation of the second drive wheel (34) about the second axis of rotation (36), the engagement of the second pin in the second sliding gate and thus a movement of the second drive wheel (34) effected by the second pin and the second sliding gate from the second decoupling position into the second actuating position are omitted, into a second engaging position, in which, during a complete rotation of the second drive wheel (34) about the second axis of rotation (36), the second pin can be brought into engagement with the second sliding gate, as a result of which a movement of the second drive wheel (34) from the second decoupling position into the second actuation position can be effected.Transmission (1) according to Claim 8, characterized in that the drive wheels (10, 34) rotate in opposite directions during operation of the transmission (1), with the result that the first drive wheel (10) can be used to effect a rotation of the starwheel (7) in a first rotational direction (14) and the second drive wheel (34) can be used to effect a rotation of the starwheel (7) in a second rotational direction (22) which is opposite the first rotational direction (14).Transmission (1) according to Claim 8 or 9, characterized in that the drive wheels (10, 34) mesh directly with one another.

Images