Shift drum mechanism, shift transmission having a shift drum mechanism, and single-track vehicle having such a shift transmission having said shift drum mechanism

Abstract

The invention relates to a shift drum mechanism for actuating a form-fitting element for shifting a shift stage in a manual transmission, having a shift shaft (1) which is rotatable about a shift axis (2), and having a shift drum (5) arranged concentrically with respect to the shift axis, wherein the shift drum (5) has at least one shifting groove (6, 7, 8) which runs in a shift drum circumferential direction (9) at least in some sections around the latter and is designed as a shifting gate which has a shifting gradient (31) at least in some sections, which is designed to generate an axial shifting movement in the axial direction (21) on the basis of a rotational movement of the shift drum (5) about the shifting axis (2), wherein, in relation to a torque transmission direction from the shift shaft (1) to the shift drum (5), a shifting jerk decoupling device (11) is arranged between them, and wherein the shift drum (5) and the shift shaft (1) are coupled to one another by means of said shifting jerk decoupling device (11) in order to transmit torque.

Description

[0001] Shift drum mechanism, manual transmission with shift drum mechanism and single-track vehicle with such a manual transmission with this shift drum mechanism

[0002] The invention relates to a shift drum mechanism, a manual transmission with such a shift drum mechanism, and a single-track vehicle with such a manual transmission with this shift drum mechanism. A shift fork and shift arrangement for a gear-change transmission are known from DE 10 2021 100 861 A1.

[0003] The invention is described below with reference to an unsynchronized, manually and sequentially shifted motorcycle transmission; this is not to be understood as a restriction of the invention to such an application. In such a manual transmission, which has several gear stages with different gear ratios to represent different gear ratios, a shift shock can occur when changing gears, i.e. when switching from one gear stage to another. Such a shift shock is caused by the existing difference in speed between the current gear and the gear to be engaged, which is also necessary for a quick gear change. During a shift shock, forces oppose a shifting movement, i.e. the movement of an actuating device for engaging the gear.Forces opposing the movement of the shift mechanism are undesirable, as they can lead to additional component stress and a loss of comfort. The cause of this undesirable reaction is what is known as shift claw impact. In such an unsynchronized transmission, gear changes occur by disengaging (disengaging the previously engaged gear) and engaging (engaging the new gear) using positive shifting elements, known as claw clutches. The beveled edges of the claws of the claw clutch being engaged can collide, creating an impulse that opposes the actuation (engagement) both in terms of effect and direction of movement.The energy transferred depends, among other things, on the rigidity and inertia of the individual components in the gearshift mechanism. In a mechanical motorcycle transmission, this includes the components of the foot shift lever, transmission components, shift drum, and the shift fork for engaging the respective dog clutch. Due in particular to the dynamic nature of a motorcycle transmission, these reactive forces can exceed the actuation forces required to engage the gear and lead to excessive stress on individual components of the gearshift mechanism and the transmission. This reactive effect can occur equally during both upshifts and downshifts.

[0004] Against this background, it is an object of the invention to provide a shift drum mechanism that relieves at least parts of the shifting device of such forces, or to provide a motorcycle transmission with such a shift drum mechanism, or to provide a single-track vehicle, in particular a motorcycle, with such a motorcycle transmission. These objects are achieved by a shift drum mechanism according to claim 1, a manual transmission according to claim 11, and a single-track vehicle according to claim 13.

[0005] In other words, the invention describes, among other things, a technical measure that reduces the maximum level of feedback when engaging a gear in an unsynchronized manual transmission. The invention is described independently of the actuation of a shifting element in the manual transmission; in particular, in a motorcycle transmission, a so-called shift fork is used to actuate the shifting element to shift a gear. Such a shift element is therefore arranged on a transmission shaft and designed to establish a positive connection. In particular, when the manual transmission is operated manually, such a shift fork can be actuated via the driver's foot, which applies the actuating force to a foot shift lever, and further via a shift drum and another mechanism.

[0006] Regardless of the actuation (manual, motorized), the invention is also applicable if the switching force is applied by motor, in particular electrically, pneumatically, hydraulically or by means of a spring device.

[0007] For the purposes of the invention, a shift drum mechanism is understood to be a mechanism for actuating a positive-locking element for shifting a gear in a manual transmission. Furthermore, such a mechanism is understood to be a mechanism which transmits a preferably manually or preferably motor-specified shift command for changing, or engaging or disengaging, a gear in a manual transmission to a shift element. Such a shift drum mechanism has a rotatable shift shaft, wherein this shift shaft is rotatable about a shift axis or an axis that is, in particular, axially parallel to the shift axis, and in particular this shift shaft has at least one or more bearing points for rotatably supporting it about such an axis. In figurative geometric terms, the shift axis can be understood as a longitudinal axis of the shift drum mechanism.In addition to the selector shaft, the shift drum mechanism also has a transmission drum; in a preferred embodiment of the invention, this can be designed as a transmission drum. The transmission drum is arranged concentrically to the shift axis; if the transmission drum is not designed as a transmission drum, the transmission drum can also be rotatably mounted about an axis parallel to the shift axis, which axis is not necessarily arranged concentrically to the shift axis. A basic idea of ​​the invention is to decouple the selector shaft and the transmission drum from one another, at least to a certain extent. In this sense, decoupling is understood to mean a force limitation during the power transmission from the selector shaft to the transmission drum, or vice versa.

[0008] If the transfer roller is not directly designed as a shift roller, the transfer roller is configured to transfer the rotational movement applied to the shift shaft for shifting a gear to the shift roller. Preferably, the transfer roller is mechanically coupled to the shift roller, preferably kinematically positively coupled, and more preferably, such a coupling takes place with a shaft, preferably with a linkage, and particularly preferably with at least two gears.In particular, in an embodiment in which the transfer roller is designed as a shift roller, a particularly compact design of the shift roller mechanism is enabled, and in particular in an embodiment in which the movement is transmitted from the shift shaft to the transfer roller and from there to the shift roller, which is then designed in particular as a separate component from the transfer roller, a geometric separation of the shift roller from the shift shaft is enabled. In an embodiment of the invention in which such a separation of the shift roller from the shift shaft is carried out, the axis about which the shift roller is rotatably mounted can deviate from the shift axis, thus enabling a flexible arrangement.

[0009] The mechanical principle of such a shift drum as such is known, in particular from a motorcycle transmission or a sequentially shiftable transmission. The invention aims at mechanically decoupling such a shift drum. In particular for translating a rotary movement into a longitudinal movement, as is regularly advantageous for actuating a shifting element such as a dog clutch or a sliding gear, such a shift drum has at least one shift groove or a correspondingly shaped raised area. Such a shift groove or raised area runs in a shift drum circumferential direction, at least in sections, around this shift drum and is accordingly designed as a shift gate which has a shift gradient at least in sections.The shift groove or raised area is thus designed to generate an axial shift movement, i.e., a movement along the shift axis or along the rotational axis of the shift drum due to a rotational movement of the shift drum about the corresponding axis. A transmission element or such a shift fork engages in the shift groove to transmit this shift movement to a shift fork.

[0010] In a first embodiment of the invention, the transfer roller is not designed as a shift roller, but is preferably directly or indirectly kinematically coupled to such a roller for movement transmission. In this first embodiment, this transfer roller is kinematically coupled to the shift roller, such coupling preferably taking place by means of gears or preferably another suitable transmission mechanism, such as preferably at least one shaft or preferably a linkage. In particular, in this first embodiment of the invention, the transfer roller is preferably permanently mechanically coupled to the shift roller and can be arranged geometrically remote from it or independent of its position; the decoupling of a shift pulse is then achieved by the shift pulse decoupling device between the shift shaft and the transfer roller.

[0011] In a second embodiment of the invention, the transfer roller is designed as a shift roller. In particular, such a second embodiment enables a direct transmission of the movement required for shifting a gear from the shift shaft to the shift roller by means of the shift shock decoupling device.

[0012] According to a basic idea of ​​the invention, with respect to a transmission direction from the selector shaft to the transmission roller, which, as explained, can be designed as a selector roller, a shifting impulse decoupling device is arranged between the selector shaft and the transmission roller. In other words, a transmission of force from the selector shaft to the transmission roller, and preferably also vice versa, takes place by means of this shifting impulse decoupling device, wherein the shifting impulse decoupling device is to be understood in the sense of the invention as a force-limiting device and thus the force that can be transmitted between the selector shaft and the transmission roller is limited. In particular, by means of such a configuration of the shifting roller mechanism, it is prevented that large forces, in particular those that could damage the mechanical components of the shifting roller mechanism or other transmission components, are transmitted from the latter.Further preferably, the switching shock decoupling device is designed as a reversible force limiting device, so that it is preferably deflected from an initial position when a switching shock occurs and thus prevents a harmful effect of the switching shock and after the switching shock, the switching shock decoupling device returns to its initial position.

[0013] In a preferred embodiment, the shift drum mechanism has at least one shift drum coupling element, which is connected in a rotationally fixed manner to the transfer drum. Furthermore, the shift drum mechanism has at least one shift shaft coupling element, which is connected in a rotationally fixed manner to the shift shaft. In particular, to decouple the shift drum mechanism, i.e., to prevent the transmission of forces caused by a shift shock, which could directly or indirectly lead to damage, a decoupling spring device is provided to connect these elements. This decoupling spring device has at least one decoupling spring. This at least one decoupling spring device is configured to apply a decoupling spring force. The decoupling spring force prestresses the shift drum and shift shaft coupling elements against each other.The effective direction of the decoupling spring force is preferably aligned at least partially or preferably completely orthogonal to the shift axis, and more preferably, the effective direction of the decoupling spring force is aligned at least partially or preferably completely parallel to the shift axis, or in the direction thereof. In particular, such an orthogonal alignment of the effective direction of the decoupling spring force enables a design of the shift drum mechanism with a small installation space requirement in the direction of the shift axis. In particular, such an axis-parallel alignment of the effective direction of the decoupling spring force to the shift axis enables a design of the shift drum mechanism with a small installation space requirement orthogonal to the shift axis.

[0014] It is further proposed that the shift drum coupling element has a shift drum decoupling surface and the shift shaft coupling element has a shift shaft decoupling surface. In the context of the invention, these surfaces are understood to be those surfaces of the shift drum coupling element and the shift shaft coupling element which contact each other at least indirectly or preferably directly under the action of the decoupling spring force and are thus decisive for providing the decoupling functionality in this embodiment. In particular, when providing the decoupling, the shift shaft decoupling surface and the shift drum decoupling surface slide against each other. The shift shaft coupling element and the shift drum coupling element contact each other at least at certain points and thus at a so-called engagement contact point, which lies on these decoupling surfaces (shift shaft decoupling surface, shift drum decoupling surface).Preferably, the shift drum coupling element and the shift shaft coupling element contact each other at least along an engagement contact line or, more preferably, within an engagement contact surface. At least one of these decoupling surfaces, but preferably both, have a surface normal at this at least one engagement contact point, a so-called decoupling surface normal, which is inclined relative to the shift axis. More preferably, this decoupling surface normal is inclined relative to the shift axis in such a way that a rotational movement of the transfer drum, particularly when designed as a shift drum, relative to the shift shaft about the shift axis, causes a movement of the shift shaft coupling element relative to the shift drum coupling element, particularly in the direction of the shift axis, and a change in the decoupling spring force, particularly an increase thereof.In other words, when the decoupling spring force is aligned parallel to the axis, one of the coupling elements (shift shaft coupling element, shift drum coupling element) displaces the other in the longitudinal direction, specifically in the direction of the shift axis. Furthermore, this displacement occurs against the decoupling spring force, and the transmission of a rotational movement from one coupling element to the other does not occur.

[0015] In one embodiment, the shift drum coupling element or the shift shaft coupling element can be designed as a type of ramp, or inclined plane, in the region of the respective decoupling surface, and the other coupling element contacts this region, i.e., the so-called ramp region. Preferably, this other coupling element is designed to be opposite to the ramp region in terms of its geometric design or, more preferably, has a spherical shape relative to it, in order to enable good contact between the shift shaft and shift drum elements.As explained, in such an embodiment, the decoupling spring force counteracts the above-explained movement of the coupling elements (shift shaft coupling element, shift drum coupling element), i.e., in particular, a movement of one of these elements in the direction of the shift axis. The geometric design of this ramp region determines how strongly the decoupling spring force counteracts such a movement. Particularly with such a design of the shift drum mechanism, the decoupling function can be influenced by the geometric design of the shift shaft and shift drum coupling element, as well as by the decoupling spring.

[0016] In a further preferred embodiment, a plurality of such shift drum coupling elements and shift shaft coupling elements are provided, but at least two of each. Further preferably, each such shift drum coupling element contacts at least one such shift shaft coupling element. In particular, improved decoupling functionality can be achieved by using a plurality of such coupling elements, and operational reliability is further improved by a plurality of redundant elements.

[0017] In a preferred embodiment, at least two selector shaft coupling elements are arranged spaced apart from one another along the selector axis. These selector shaft coupling elements are further preferably arranged mirror-inverted to one another. In particular, such an arrangement of the selector shaft coupling elements cancels out the forces occurring at one of these selector shaft coupling elements when providing the decoupling functionality and those occurring at the other of these selector shaft coupling elements.

[0018] In a preferred embodiment, the at least one decoupling spring is arranged geometrically between these at least two selector shaft coupling elements, which are further preferably arranged mirror-symmetrically to one another. Such a geometric arrangement, in particular, enables a space-saving design.

[0019] In a preferred embodiment, at least two shift drum coupling elements are arranged spaced apart along the shift axis, i.e., at a distance from one another. Preferably, the at least two shift drum coupling elements are arranged mirror-symmetrically to one another. Such an arrangement, in particular, enables a space-saving design.

[0020] In a preferred embodiment, the at least one decoupling spring is arranged geometrically between these at least two shift drum coupling elements.

[0021] In a preferred embodiment of the invention, the selector shaft coupling element has at least one decoupling ramp region. The decoupling ramp region is preferably delimited at least in sections by the selector shaft decoupling surface. Further preferably, the selector shaft coupling element has a plurality of such decoupling ramp regions. Further preferably, at least one of the selector drum coupling elements has at least one decoupling engagement region. The decoupling engagement region is preferably delimited at least in sections by the selector drum decoupling surface. Preferably, the selector drum coupling element has a plurality of such decoupling engagement regions. Further preferably, at least one of these decoupling engagement regions projects in the direction of the selector axis, in particular in the longitudinal direction, into the decoupling ramp region and thus into the selector shaft coupling element.Furthermore, in such a configuration, the shift drum coupling element and the shift shaft coupling element preferably overlap at least in sections in the direction of the shift axis, i.e. in the longitudinal direction.

[0022] In a preferred embodiment, two mutually symmetrical shift drum coupling elements and preferably two mutually symmetrical shift shaft coupling elements are provided. Preferably, the at least one decoupling spring is arranged coaxially to the shift axis, in particular with respect to the decoupling spring force applied by this decoupling spring; in particular in such an embodiment, the effective direction of the decoupling spring force is axially parallel to the shift axis. Further preferably, the decoupling spring is arranged such that the decoupling spring force forces the two shift shaft coupling elements away from one another. Preferably, the decoupling spring is designed as a compression spring, thus in particular pressing them apart, and wherein the decoupling spring force preloads the shift shaft coupling elements against the shift drum elements. In particular, such an embodiment enables a space-saving design.

[0023] Furthermore, a manual transmission is proposed, in particular a transmission shiftable in individual, discrete shift stages, so-called gears, which are predetermined in particular by gearwheels. In this manual transmission, a shift drum mechanism is provided in one of the previously explained embodiments for changing at least individual gears or shift stages. Furthermore, the proposed manual transmission has at least one transmission input shaft and at least one transmission output shaft. In particular, this manual transmission has at least two selectively shiftable shift stages for power transmission, so-called gears. Preferably, at least one of these shift stages, and preferably several, can be shifted by means of a positive-locking mechanism. Such a positive-locking mechanism can preferably be designed as a dog clutch and more preferably as a sliding gear or the like.Further preferably, the proposed shift drum mechanism is provided for transmitting an actuating force to or toward this positive-locking mechanism. This actuating force can preferably be provided directly by a vehicle operator using an actuating device, in particular by foot or hand actuation, and furthermore, such an actuating force can be provided by a motorized actuator, particularly in the case of a partially or fully automated manual transmission. The application of the proposed shift drum mechanism is particularly advantageous, particularly in the configuration as a manual transmission with an actuator for providing the actuating force, thus preferably as an automated manual transmission or at least as a manual transmission with an automated operating mode.As explained, a motorized drive for the shift shaft is necessary to implement an automated shifting system. Such a motorized drive, in particular an actuator, is directly or indirectly coupled to the shift shaft and typically exhibits a high mass inertia compared to manual actuation of this shift shaft (foot or hand shift lever). In particular, the combination of this mass inertia and the high acceleration caused by a shift shock can lead to high forces in the shift mechanism, and these high forces are avoided or at least reduced by the proposed shift drum mechanism.

[0024] Furthermore, this actuating force for a gear change is applied to this shift shaft. In particular, the proposed shift drum mechanism results in a decoupling of the actuating device or actuator from feedback effects on the shift drum mechanism, thus achieving a particularly reliable manual transmission.

[0025] In a preferred embodiment, the manual transmission is designed as a partially or preferably completely unsynchronized manual transmission. Further preferably, at least one such positive-locking mechanism, preferably a plurality of such positive-locking mechanisms, comprises a sliding sleeve with a dog clutch or a sliding gear, wherein, to engage or disengage an unsynchronized gear, a displacement of such a sliding sleeve or such a sliding gear is carried out by means of the proposed shift drum mechanism and a further mechanism, in particular with one or more shift forks or the like. In particular, such an embodiment enables a comfortably shiftable manual transmission to be realized.

[0026] Furthermore, a single-track vehicle, in particular a motorcycle or the like, with a manual transmission in one of the previously described embodiments is proposed.

[0027] In the following, individual features and embodiments of the invention are explained in more detail with reference to the figures, the representations are at least partially simplified and furthermore, other combinations of features than those shown are also possible in principle, in which:

[0028] Fig. 1 : a three-dimensional sectional view of a shift drum mechanism, Fig. 2: a three-dimensional view of the shift shaft with shift drum,

[0029] Fig. 3: a three-dimensional representation of the selector shaft without a selector drum but with a decoupling spring device, Fig. 4: a highly schematic partial representation of an operating principle of an embodiment of the selector drum mechanism in the initial state,

[0030] Fig. 5: a highly schematic partial representation of an operating principle of an embodiment of the shift drum mechanism in the decoupling state,

[0031] Fig. 6: a three-dimensional view of a gear set of a manual transmission with shift drum mechanism,

[0032] Fig. 7: Schematic representation of an embodiment in which the transfer roller is not designed as a switching roller.

[0033] Figure 1 shows a three-dimensional sectional view of the proposed shift drum mechanism in one embodiment for actuating a motorcycle transmission. The shift drum mechanism shown is designed to actuate several positive-locking elements (not shown) by means of so-called shift forks (not shown) for shifting gears, i.e., different gear ratios, in a motorcycle transmission. The shift drum mechanism has a shift shaft 1, which consists of several components, including a shift force transducer 3 for receiving an actuating movement and actuating force from an actuating lever (not shown) or an actuating actuator (not shown). The shift shaft 1 is rotatably mounted about a shift axis 2; a shift shaft bearing 4 is shown from the bearing for supporting the shift shaft 1 in the motorcycle transmission.Furthermore, the shift drum mechanism has a shift drum 5 arranged concentrically to the shift axis 2, which transfers the shifting movement to the shift fork (not shown). In the illustrated embodiment, the transfer drum is therefore designed as a shift drum 5. The illustrated shift drum 5 has three shift grooves 6, 7, 8, which extend at least partially around the shift drum 5 in a shift drum circumferential direction 9 and are designed as shift gates. The shift gates each have, at least in sections, a shift pitch, which leads to the generation of an axial shifting movement due to a rotational movement of the shift drum 5 about the shift axis 2, i.e., to the translation of the rotational movement about the shift axis into a movement in the longitudinal direction 10.It is further proposed that, with respect to a torque transmission direction from the selector shaft 1 to the selector drum 5, a shift shock decoupling device 11 be arranged between them, and wherein the selector drum 5 and the selector shaft 1 are coupled to one another by means of this shift shock decoupling device 11. Furthermore, the shift shock decoupling device 11 can be understood as a type of overload clutch; if a shift shock occurs which exceeds a certain force value, as can be the case with incorrect operation of the shift drum mechanism, the shift shock decoupling device 11 decouples the selector shaft 1 from the selector drum 5, and this shift shock is then no longer transmitted.

[0034] The shifting impulse decoupling device 11 has two shifting drum coupling elements 12, 13, which are rotationally connected to the shifting drum 5, and two shifting shaft coupling elements 14, 15, which are rotationally connected to the shifting shaft 1. Furthermore, the shifting impulse decoupling device has a decoupling spring device 16, which has a decoupling spring 17, which is designed as a spiral spring and which applies the decoupling spring force, i.e., a force in the direction along the shifting axis 2. The decoupling spring force thus prestresses the shifting drum coupling elements 12, 13 and the shifting shaft coupling elements 14, 15 against each other.

[0035] Figure 2 shows the shift drum mechanism in a three-dimensional, uncut view. As in the embodiment shown in Figure 1, the transfer drum in this embodiment is also designed as a shift drum 5. The three shift grooves 6, 7, 8 and their shift pitch, as well as their course around the shift drum 5, are clearly visible on the shift drum 5.

[0036] Figure 3 shows a three-dimensional representation of the shift drum mechanism known from Figure 2 without the shift drum 5 (not shown in Figure 3), clearly illustrating the decoupling of the shift shaft 1 from the shift drum (5, not shown) by means of the shift shaft decoupling device 11. The shift drum coupling elements 12, 13 have 10 recesses with shift drum decoupling surfaces in the longitudinal direction, and the shift shaft coupling elements 14, 15 engage in these recesses with their shift shaft decoupling surfaces. The decoupling spring 17 preloads the shift shaft coupling elements along the shift axis against the shift drum coupling elements, so that they contact each other in pairs (12 / 14 or 13 / 15) at the engagement contact points on these decoupling surfaces.

[0037] As shown, the decoupling surfaces are inclined relative to the shift axis, at least where the shift drum and shift shaft coupling elements contact each other. A rotational movement of the shift drum (not shown) is transmitted directly to the shift drum coupling elements 12, 13 which are connected to it in a rotationally fixed manner; such a rotational movement can be caused, for example, by a shift shock. The shift shaft coupling elements 14, 15 are in engagement with the shift drum coupling elements 12, 13, so that the rotational forces are transmitted to them. The shift shaft 1, to which the shift shaft coupling elements 14, 15 are connected in a rotationally fixed manner, is not freely rotatable during normal operation of the shift drum mechanism, since the shift shaft 1 is kinematically coupled to a shift lever (not shown) or a shift actuator (not shown) via the shift force transducer 3.By means of the shifting shaft decoupling device, the shifting shaft coupling elements 14, 15 are displaced toward each other on the shifting shaft, compressing the decoupling spring 17 without excessive forces being transmitted through this shifting drum mechanism. Ultimately, the shifting drum 5 (not shown) and with it the shifting drum coupling elements 12, 13 rotate relative to the shifting shaft 1 about the shifting axis, resulting in a movement of the shifting shaft coupling elements 14, 15 relative to the shifting drum coupling elements 12, 13. The movement of the shifting shaft coupling elements along the shifting axis 2 leads to a change in the decoupling spring force.

[0038] Figures 4 and 5 show a partial representation of the operating principle of an embodiment of the shift drum mechanism in one representation plane. In particular, this representation shows the decoupling function of the relay drum, which is embodied here as shift drum 5, with respect to the shift shaft 1. Figure 4 shows an initial state (no shift shock) and Figure 5 shows a decoupling state (shift shock decoupled). The decoupling spring 17 is arranged concentrically to the shift axis 2. A shift shock on the shift drum 5 leads to a movement of the shift drum coupling element 12, which is connected in a rotationally fixed manner to the shift drum 5, in the representation plane in direction 20, i.e., to a rotation about the shift axis 2. The shift drum coupling element 12 and the shift shaft coupling element 14 contact each other at contact point 18.The contact surface of the selector shaft coupling element 14 is inclined relative to the selector axis 2, as can be seen in particular from the surface normal 19. Furthermore, the switching gradient 31 resulting from the inclination relative to the selector axis 2 can be seen in this planar representation. The decoupling spring 17 tensions the selector shaft coupling element 14 against the selector drum coupling element 12 by means of the decoupling spring force. Due to the switching impulse, the selector shaft coupling element deviates in the linear direction of movement 21 and tensions the decoupling spring 17. Due to this movement of the selector shaft coupling element in the linear direction of movement 21, the switching impulse is not transmitted to the selector shaft as an angular momentum, and thus a switching impulse decoupling of the selector shaft 1 from the selector drum 5 is achieved.The displacement path, in particular the rotational path (direction 20) of the shift drum coupling element 12 relative to the shift shaft coupling element 14, can be limited by a rotational path stop. When the shifting impulse subsides, the shift drum coupling element 12 and the shift shaft coupling element 14 each return to their initial positions, and a new shifting impulse can be decoupled. Figure 5 shows how the shift drum coupling element is moved out of its initial position (Figure 4), thereby displacing the shift shaft coupling element 14 in the linear direction of movement 21, and thus compressing the decoupling spring 17.

[0039] Figure 6 shows a three-dimensional representation of a straight-toothed 6-speed manual transmission, without a transmission housing. The gears intended for power transmission are designed as straight-toothed gears 25-30. To establish the rotationally fixed connections for the gears, this manual transmission does not have any synchronizers and is therefore designed as an unsynchronized 6-speed manual transmission. Shifting (engaging / disengaging different gears) is achieved by moving sliding gears using the shift forks 22, 23 shown.When shifting, the gear to be disengaged is decoupled by moving a sliding gear, breaking the existing claw contact (gear to be disengaged / transmission shaft). The gear to be engaged is then coupled by moving another or the same sliding gear, thus establishing a new claw contact (gear to be engaged / transmission shaft). The sliding gears are shifted by shift forks 22, 23, which engage in a groove of the sliding gear to be shifted. Each shift fork is designed to shift a maximum of two gears.

[0040] The shift forks 22, 23 are driven via a curved path, i.e., the so-called shift grooves, which are provided in the circumferential direction on the rotatable shift drum 5 of the proposed shift drum mechanism. In the illustrated embodiment, the transfer drum is designed as a shift drum 5. A shift increment between two gears is typically 60°, in particular based on the rotational path of the shift drum about its axis of rotation, in this case the shift axis. The shift drum mechanism and thus the shift drum 5 are driven by means of a stepping mechanism on the shift shaft 1, with the movement being transmitted from the latter to the shift drum 5 via the decoupling device. The stepping mechanism can, as explained, be operated manually by hand or, more usually, by foot, or, in addition to or as an alternative to this manual operation, a motor drive, preferably an electric motor drive, can be provided.

[0041] The proposed shift drum mechanism can be used with straight and helical gears, regardless of the number of gears; furthermore, such a shift drum mechanism can also be applied analogously to other types of shift kinematics. Figure 7 shows a highly schematic partial view of an embodiment in which the transfer drum is not designed as a shift drum 5. Rather, the transfer drum, which is rotatable about the shift axis 2 and concentric with it, transfers the actuating force applied by the foot lever 32 for changing gears to the shift drum 5 with the aid of a stepping mechanism 34 via the transmission gears 34. In an automated manual transmission, a shift actuator (not shown) can be provided instead of the foot lever 32.

[0042] The shift drum 5 is mounted for rotation about the axis 33; this axis 33 is aligned parallel to the shift axis 2 but not concentric with it. The shift drum 5 shown in this figure has two shift grooves 6 and 7, into which the shift forks 22 and 23 engage. A rotational movement of the shift drum 5 about its axis of rotation 33 leads to a displacement of these shift forks 22, 23, depending on the design of the shift grooves 6, 7, in a direction parallel to this axis of rotation 33. This displacement allows gears to be engaged or disengaged in a manual transmission (not shown).

[0043] A shifting impulse applied to the shift drum 5 by at least one of the shift forks 22, 23 can lead, via the respective shifting groove 6, 7, to a rotational movement of the shift drum 5 about its rotational axis 33, which is transmitted via the transmission gears 34 in the direction of the foot lever 32. In the shifting impulse decoupling device 11, which is arranged concentrically to the shifting axis 2 and geometrically integrated into the transfer drum, the foot lever 32 is decoupled from this shifting impulse, provided the shifting impulse exceeds a limit value predetermined by the design of the shifting impulse decoupling device 11.

Claims

Claims 1. A shifting mechanism for actuating a positive-locking element for shifting a gear in a manual transmission, comprising a shift shaft (1) which is rotatable about a shift axis (2) and comprising a transfer roller arranged concentrically to the shift axis (2), wherein the transfer roller is configured directly or indirectly to transfer an actuating movement to a shift drum (5) or is designed as such a shift drum (5), and wherein such a shift drum (5) has at least one shift groove (6, 7, 8) which runs at least partially around the shift drum (5) in a shift drum circumferential direction (9) and is designed as a shift gate which has at least partially a shift pitch (31) which is designed to generate an axial shift movement in the axial direction (21) due to a rotational movement of the shift drum (5) about its axis of rotation (2,33) and wherein, with respect to a torque transmission direction from the selector shaft (1) to the transfer roller, a switching impulse decoupling device (11) is arranged between this selector shaft (1) and this transfer roller, and wherein the transfer roller and the selector shaft (1) are coupled to one another by means of this switching impulse decoupling device (11) for torque transmission.

2. Shift drum mechanism for actuating a positive locking element for shifting a gear in a manual transmission, with the shift shaft (1) which is rotatable about the shift axis (2) and with the transfer drum which is arranged concentrically to the shift axis and is designed as a shift drum (5), wherein the shift drum (5) has at least one such shift groove (6, 7, 8) which is designed as a shift gate and is configured to generate an axial shifting movement, wherein, with respect to a torque transmission direction from the shift shaft (1) to the shift drum (5), the shift shock decoupling device (11) is arranged between the shift shaft 1 and the shift drum (5), and wherein the shift drum (5) and the shift shaft (1) are coupled to one another by means of the shift shock decoupling device (11) for torque transmission.

3. Shift drum mechanism according to claim 1 or 2, characterized in that the shifting shock decoupling device (11) has at least one shifting drum coupling element (12, 13), which is rotationally connected to the transfer drum, and at least one shifting shaft coupling element (14, 15), which is rotationally connected to the shifting shaft (1), and with a decoupling spring device (16), which has at least one decoupling spring (17) and which applies a decoupling spring force which prestresses the at least one shifting drum (12, 13) and the at least one shifting shaft coupling element (14, 15) against each other, and that the at least one shifting drum coupling element (12, 13) has a shifting drum decoupling surface and the at least one shifting shaft coupling element (14, 15) has a shifting shaft decoupling surface, and that at least two of these coupling elements (12, 13, 14,15) at at least one engagement contact point (18) on these decoupling surfaces, and that at least one of the decoupling surfaces in at least one such engagement contact point (18) has a surface normal, so-called decoupling surface normal (19), which is inclined relative to the switching axis (2), so that a rotational movement of the transfer roller relative to the switching shaft (1) about the switching axis (2) causes a movement of the at least one switching shaft coupling element (14, 15) relative to the at least one switching drum coupling element (12, 13) and a change in the decoupling spring force.

4. Shift drum mechanism according to claim 3, characterized in that at least two shift drum coupling elements (12, 13) and at least two shift shaft coupling elements (14, 15) are present.

5. Shift drum mechanism according to claim 4, characterized in that at least two shift shaft coupling elements (14, 15) are arranged spaced apart from one another along the shift axis (2).

6. Shift drum mechanism according to claim 4, characterized in that the at least one decoupling spring (17) is arranged geometrically between these at least two shift shaft coupling elements (14, 15).

7. Shift drum mechanism according to one of claims 4 to 6, characterized in that at least two shift drum coupling elements (12, 13) are arranged spaced apart from one another along the shift axis (2).

8. Shift drum mechanism according to claim 7, characterized in that the at least one decoupling spring (17) is arranged geometrically between these at least two shift drum coupling elements (12, 13).

9. Shift drum mechanism according to one of claims 1 to 8, characterized in that at least one of the shift shaft coupling elements (14, 15) has at least one decoupling ramp region which is at least partially delimited by the shift shaft decoupling surface and that at least one of the shift drum coupling elements (12, 13) has at least one decoupling engagement region which is at least partially delimited by the shift drum decoupling surface and that the at least one decoupling engagement region projects into the shift shaft coupling element (14, 15) in the direction of the shift axis in the decoupling ramp region.

10. Shift drum mechanism according to claim 8, characterized in that two mutually symmetrical shift drum coupling elements (12, 13) and two mutually symmetrical shift shaft coupling elements (14, 15) are present and that the decoupling spring (17) is arranged coaxially to the shift axis (2) with respect to the decoupling spring force applied by it and that the decoupling spring force forces the two shift shaft coupling elements (14, 15) away from one another and prestresses each against the shift drum coupling elements (12, 13).

11. Manual transmission with a shift drum mechanism according to one of the preceding claims, characterized in that this manual transmission has at least one transmission input shaft and at least one transmission output shaft and that this manual transmission has at least two selectively switchable shift stages for power transmission from the transmission input shaft to the transmission output shaft, and that at least one of these shift stages is switchable by means of a form-locking mechanism and that this shift drum mechanism is provided for transmitting an actuating force to this form-locking mechanism.

12. Manual transmission according to claim 11, characterized in that the manual transmission is designed as an unsynchronized manual transmission and that the positive locking mechanism has a sliding sleeve with a claw coupling section, or a sliding gear with such a section.

13. Single-track vehicle with a manual transmission according to one of claims 11 or 12.

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