Bottom bracket gearbox for a muscle-powered vehicle

Abstract

Bottom bracket gearbox for a muscle-powered bicycle or pedelec, wherein the bottom bracket gearbox comprises a drive element (1), a switching device with switching elements, an actuating unit with switching cams (41, 42, 43, 44), a planetary roller (10) with planetary gear set elements, a stationary component (3) and an output element (2), wherein the drive element (1) is mechanically operatively connected to the output element (2) by means of the planetary roller (10), at least two planetary gear set elements can be fixed to the stationary component (3) by closing one of the switching elements, one of the planetary gear set elements is formed by a sun gear (12, 17, 22, 27), a planet carrier (13, 18, 23, 28) or a ring gear (15, 20, 25, 30), the switching cams (41, 42, 43, 44) by means of the switching device so are mechanically connected to the switching elements,that the switching elements can be switched between an open and a closed switching state by adjusting the actuating unit, the planetary roller (10) provides different transmission ratios by means of a combination of switching states of the switching elements, and the switching elements comprise brake pawls (B1, B2, B3, B4) which are rotatably mounted, extend in a longitudinal direction, can be in contact at one end in a longitudinal direction with a switching cam (41, 42, 43, 44), and have a pawl at the other end in a longitudinal direction which can be coupled to one of the planetary gear set elements, characterized in that the actuating unit and the switching device are arranged such that before reaching at least one target switching state of the switching elements, an intermediate switching state is engaged which sets a transmission ratio in the planetary roller (10) that is smaller than the transmission ratio in the target switching state,in the intermediate switching state each brake pawl (B1, B2, B3, B4) is closed.

Description

Technical area

[0001] The present invention relates to a bottom bracket gear for a human-powered vehicle. Furthermore, the present invention relates to a bicycle or pedelec with the bottom bracket gear. State of the art

[0002] For example, from the publication DE 10 2019 220 044 B4, an arrangement for switching at least one brake pawl of a bottom bracket transmission is known. The brake pawls lock or release a planetary gear set element by rotating a shift drum. The geometry of the elevations of the shift gates of the shift drum results in a sequence in which the individual brake pawls are actuated during shifting. The known bottom bracket transmission has the problem that a low intermediate gear is created when shifting from a low to a high gear. This is noticeable to the user as a feeling of depressing a drive pedal.

[0003] The present invention is therefore based on the object of providing an improved bottom bracket gear which has a higher riding comfort. Description of the invention

[0004] The object is achieved by means of a bottom bracket gear having the features of claim 1. Advantageous further developments are the subject of the subclaims.

[0005] A bottom bracket gear for a human-powered vehicle has a drive element, a switching device with switching elements, an actuating unit with switching gates, a planetary roller with planetary gear set elements, a stationary component, and an output element. The vehicle can be a bicycle, an e-bike, or a pedelec. A switching element can be used to selectively establish or break a rotationally fixed connection between two elements. If a switching element is closed, the rotationally fixed connection is established. If one of the elements is a stationary component, the other element is fixed to the stationary component in the closed state. If a switching element is open, the rotationally fixed connection is broken. Then one element is separated from the other element. An open state and a closed state of the switching element form a switching state of the switching element.A non-rotatable connection between two elements is understood to be a connection in which the two elements are rigidly coupled to each other under all intended conditions of the transmission, so that they essentially have the same rotational speed. A shifting element can be a clutch, for example a frictional clutch such as a multi-disk clutch, or a positive clutch such as a claw or ratchet clutch. A shifting element can also be designed, similar to a freewheel, to establish a non-rotatable connection in only one direction of rotation.

[0006] The input element is mechanically connected to the output element via the planetary roller. If two elements are mechanically connected, they are directly or indirectly coupled to one another in such a way that a movement of one element causes a reaction in the other. For example, a mechanically connected connection can be provided by a positive or frictional connection. The mechanically connected connection can correspond to the meshing of corresponding gears of the two elements. Additional elements, such as one or more spur gear stages, can be provided between the elements.

[0007] At least two planetary gear set elements can each be secured to the stationary component by closing one of the shifting elements, for example, when a shifting element is closed. One of the planetary gear set elements is formed by a sun gear, a ring gear, or a planet carrier. The stationary component can be a housing of the bottom bracket gear. The stationary component can be formed by elements of the shifting device that are immobile relative to the housing in certain operating states of the bottom bracket gear, for example, a shift drum.

[0008] The shift gates are mechanically connected to the shift elements by means of the shifting device in such a way that the shift elements can be switched between an open and a closed switching state by adjusting the actuating unit. Adjustment can, for example, be a rotation of the actuating unit about a central axis of one of the switching contours. A shift gate can be a circumferential contour of the actuating unit against which a component of the shifting device rests. The planetary roller provides various gear ratios by means of a combination of switching states of the shift elements. The actuating unit and the shifting device are configured in such a way that, before at least one target switching state of the shift elements is reached, an intermediate switching state is engaged which sets a gear ratio in the planetary roller that is smaller than the gear ratio in the target switching state.An open state of one switching element can occur simultaneously with a closed state of another switching element. Furthermore, all switching elements can be open or closed simultaneously. For each combination of switching states of the switching elements, a specific gear ratio results for the planetary roller.

[0009] When switching from the switching states of at least two switching elements to a target switching state, the switching sequence of the switching elements results in a smaller gear ratio of the planetary roller before the target switching state is reached than the planetary roller provides in the target switching state. In other words, before the target switching state is reached, at least one intermediate switching state is brought about by the combination of respective switching states of different switching elements. A small gear ratio leads to a high speed at the output element at a specific speed at the input element. A large gear ratio leads to a speed at the output element at a specific speed at the input element that is lower than the high speed.

[0010] In one embodiment, the switching gates can be arranged relative to one another and the switching gates and the switching elements can be configured such that an adjustment of the actuating unit causes a coordinated opening and closing of the switching elements.

[0011] In one embodiment, the switching gates can be arranged relative to one another and the switching gates and the switching elements can be configured such that, in order to achieve at least one target switching state of the switching elements, switching elements are closed before switching elements are opened.

[0012] In one embodiment, the actuating unit can have at least two shift gates. Each shift gate can have at least one elevation. Elevations of different shift gates can have the same design. Elevations of different shift gates can have different designs. The switching device can be mechanically operatively connected to the shift gates. The shift gates can be rotatably mounted with respect to their central axes. For example, the shift gates have a cylindrical or elliptical shape, from which the elevations extend radially outward. One of the elevations can cause one of the switching elements to switch by rotating one of the shift gates.

[0013] The shift gates can have the same central axis. The elevations of the respective shift gates can be offset relative to elevations of other shift gates, either in the direction of rotation or opposite to it. In other words, the elevations of different shift gates can have relative positions to one another in the circumferential direction. The circumferential direction is a direction on the outer circumference of a shift gate that points in the direction of rotation. This can cause an elevation of one shift gate to open one switching element, while an elevation of another shift gate to close another switching element. This also applies if elevations of different shift gates have the same design.

[0014] In one embodiment, the elevation can have a rising flank and a falling flank. The rising flank and the falling flank can meet between two elevations of a shift gate. In this case, a rising flank is understood to mean that the distance between the flank and the central axis increases in the circumferential direction. In this case, the circumferential direction is understood to mean a circumferential direction in which a stationary component moves relative to one of the shift gates when the shift gate is rotated. In this respect, the circumferential direction points opposite to the direction of rotation of the shift drum. In this case, a falling flank is understood to mean that the distance between the flank and the central axis decreases in the circumferential direction. In this case, the circumference of a shift gate is used as much as possible to form the flanks. This leads to a flat gradient of the flanks.This results in a low torque required for the corresponding formwork to push a rising flank under a pressure piece until the pressure piece touches the tip of the elevation.

[0015] At the transition from the rising flank to the falling flank, a peak is formed in the circumferential direction. The peak can have the greatest radial distance from the center axis. The peak can have a radius whose center lies on the center axis. Rising flanks and falling flanks can be designed the same for all elevations. Peaks can have different circumferential extensions for elevations of different shift gates.

[0016] Relative to a center of the tip in the circumferential direction, the rising flank can be designed symmetrically to the falling flank. This has manufacturing advantages. In the circumferential direction between the falling flank and the rising flank, a depression can form. The depression can be formed as a radius. This has manufacturing advantages. The depression can extend over a certain circumference of the switching contour and run concentrically to the central axis in an area with a radius. This has advantages with regard to the strength of the switching gate if, for example, this is formed on a shift drum. Depressions can be designed differently for different switching gates. For example, depressions on different switching gates can extend different distances in the circumferential direction.

[0017] In one embodiment, the rising edge and the falling edge of a protrusion can have a switching reference point. Contact of the switching device with the switching reference point can cause a switching element to switch. Contact of the switching reference point of the falling edge can cause one of the switching elements to close. In this respect, the actuating device and the switching device can be designed such that, upon rotation of the actuating device, the switching device first comes into contact with a switching reference point of a falling edge of a protrusion before it comes into contact with the switching reference point of a rising edge of another protrusion. The falling edge can be formed steeper than the rising edge. This can ensure that, at the same rotation speed of the protrusions about the central axis, the closing of the switching element is carried out faster than the opening of a switching element.

[0018] In one embodiment, the number of elevations of a shift gate can be determined according to the formula N=2 s-adepend on the number of shift gates present. Furthermore, the number of projections can be different for each shift gate. Where “N” can be the number of projections on a shift gate. “s” can be the number of shift gates. The shift gates can be numbered consecutively. Each shift gate can be assigned a number. The shift gate with the lowest number can have the largest number “N” of projections. “a” can be a consecutive integer number of a shift gate. For “a” 1 ≤ a ≤ s can apply. For example, if two shift gates are present, according to the formula the first shift gate can have two projections and the second shift gate can have one projection. For example, if three shift gates are present, according to the formula the first shift gate can have four projections, the second shift gate two projections and the third shift gate one projection.For example, if there are four shift gates, according to the formula the first shift gate can have eight elevations, the second shift gate four elevations, the third shift gate two elevations and the fourth shift gate one elevation.

[0019] Each protrusion of a shift gate, together with every second protrusion of the shift gate with the number "a" one lower, can change a shift state for a new target shift state. For example, if two shift gates are present, each protrusion of the second shift gate can participate in switching the planetary gear set to a new target shift state with every second protrusion of the first shift gate. Conversely, every protrusion of the first shift gate can participate in switching the planetary gear set to a new target state.

[0020] In one embodiment, the elevation can have a gradient in a circumferential direction that continuously decreases until its maximum extension in the radial direction. The elevation can be convex, at least in sections. This results in a slow crossing of the switching reference point and a smooth switching of the switching state.

[0021] In one embodiment, the shifting elements can be formed by brake pawls. The brake pawls can be rotatably mounted on a bearing point. The brake pawls can extend in a longitudinal direction. The brake pawls can be in contact with a shift gate at one end in the longitudinal direction. For this purpose, the brake pawls can each have a pressure piece. At the other end in the longitudinal direction, the brake pawl can have a pawl that can be coupled to a planetary gear set element. When the brake pawl is coupled to a planetary gear set element, the brake pawl can be closed and the planetary gear set element can be fixed.

[0022] The bearing point can be located between the pressure piece and the pawl, for example, centrally. This can result in a rocker arm geometry. This allows a rising flank of a protrusion to open a brake pawl. The bearing point can be located longitudinally outside the pressure piece and the pawl. This can result in a finger follower geometry. This allows a rising flank of a protrusion to close a brake pawl. Multiple brake pawls, each in contact with different shift gates, can be designed identically. This reduces the cost of the bottom bracket transmission.

[0023] A brake pawl can be designed as a pressure brake pawl. A planetary gear set element can be connected to a locking toothing in a rotationally fixed manner, for example, by means of a freewheel, or can be connected in a rotationally fixed manner. In this case, an end face of the pawl, which faces longitudinally away from the pressure piece with respect to the bearing point, can engage with the locking toothing. The planetary gear set element is then coupled to the brake pawl, and the planetary gear set element is fixed. Alternatively, the pawl can be designed as a hook, and a surface facing the pressure piece can engage with the locking toothing.

[0024] The switching reference point described above can be shifted by adjusting the geometry of a brake pawl, for example, by shortening the pressure piece or positioning the brake pawl pawl closer to the locking toothing, so that it is located closer to the peak of the elevation on the rising flank and the falling flank by changing the outer diameter of the locking toothing. Furthermore, the switching reference point can be shifted on the rising flank and the falling flank by changing the outer diameter of the locking toothing. The switching reference point can be defined on the flanks so that a small distance results between the pawl and the locking toothing when the brake pawl is open.

[0025] In one embodiment, several brake pawls can be mounted so they can rotate about a common axis of rotation. The axis of rotation can be parallel to the center axis of the shift gates.

[0026] In one embodiment, the switching device can have a first brake pawl, a second brake pawl, a third brake pawl, and a fourth brake pawl. The actuating unit can have a first shift gate, a second shift gate, a third shift gate, and a fourth shift gate, each with at least one elevation. The first brake pawl can be mechanically operatively connected to the first shift gate. The second brake pawl can be mechanically operatively connected to the second shift gate. The third brake pawl can be mechanically operatively connected to the third shift gate. The fourth brake pawl can be mechanically operatively connected to the fourth shift gate.

[0027] The planetary roller may include a first planetary gear set with a first sun gear, a first planet carrier, and a first ring gear. The planetary roller may include a second planetary gear set with a second sun gear, a second planet carrier, and a second ring gear. The planetary roller may include a third planetary gear set with a third sun gear, a third planet carrier, and a third ring gear. The planetary roller may include a fourth planetary gear set with a fourth sun gear, a fourth planet carrier, and a fourth ring gear. The planetary roller may include a first one-way clutch, a second one-way clutch, a third one-way clutch, and a fourth one-way clutch. These components may be coaxial with the input member.

[0028] Furthermore, the switching device can have a first locking toothing, a second locking toothing, a third locking toothing, and a fourth locking toothing. The second sun gear can be rotationally fixed to the first locking toothing. The second ring gear can be rotationally fixed to the second locking toothing. The third sun gear can be rotationally fixed to the third locking toothing. The fourth ring gear can be rotationally fixed to the fourth locking toothing. The second sun gear can be lockable to the stationary component by means of the first brake pawl. The second ring gear can be lockable to the stationary component by means of the second brake pawl. The third sun gear can be lockable to the stationary component by means of the third brake pawl. The fourth ring gear can be lockable to the stationary component by means of the fourth brake pawl.In this respect, the second sun gear, the second ring gear, the third sun gear and the fourth ring gear can serve as the planetary gear set elements.

[0029] The first sun gear can be rotationally fixedly connected to the second planet carrier. The first planet carrier can be rotationally fixedly connected to the input element. The first planet carrier can be rotationally fixedly connected to the second sun gear by means of the first one-way clutch. The first ring gear can be rotationally fixedly connected to the third planet carrier. The first ring gear can be rotationally fixedly connected to the second ring gear by means of the second one-way clutch. The third sun gear can be rotationally fixedly connected to the third ring gear by means of the third one-way clutch. The third sun gear can be rotationally fixedly connected to the fourth planet carrier by means of the third one-way clutch. The fourth sun gear can be rotationally fixedly connected to the output element. The fourth sun gear can be rotationally fixedly connected to the fourth ring gear by means of the fourth one-way clutch.

[0030] The first one-way clutch can be locked when the first brake pawl is open. The second one-way clutch can be locked when the second brake pawl is open. The third one-way clutch can be locked when the third brake pawl is open. The fourth one-way clutch can be locked when the fourth brake pawl is open. The inverse relationship between the switching states of the one-way clutches and the switching states of the brake pawls can apply.

[0031] In one embodiment, the actuating unit can have a locking gate for locking the shift gates in predetermined angular positions. For example, the locking gate can have sixteen locking protrusions. The locking protrusions can be evenly distributed in the circumferential direction. A spring-loaded locking mechanism can be configured to engage between the locking protrusions. The locking mechanism can be a ball lock. Particularly in the embodiment with four shift gates, a locking option is available for every possible shifting state. This leads to reliable operation of the bottom bracket gear.

[0032] In one embodiment, the actuating unit can have a common shift drum that forms the shift gates. The shift drum can form the locking gate. Different shift gates and the locking gate can be provided on different shift drums. The different shift drums can be connected to one another in a rotationally fixed manner. The shift drum can be mounted rotatably with respect to its central axis.

[0033] In one aspect, a bicycle or pedelec has a bottom bracket gear according to one of the preceding embodiments, which is driven by a drive device and drives an output device. The drive device can be mechanically operatively connected to the drive element of the bottom bracket gear. The output element of the bottom bracket gear can be mechanically operatively connected to the output device. The drive device can have a pedal crank. The drive device can have an electric motor. The output device can have a chain output or belt output. Short description of the characters Fig. 1 shows a sectional view of a schematic diagram of an embodiment of a shift gate of a shift drum. Fig. 2 shows a diagram of an embodiment of a planetary roller. Fig. 3 shows an embodiment of a shift drum. Fig. 4 shows a sectional view of an embodiment of a bottom bracket gear. Fig. 5 shows an embodiment of a second brake pawl in a sectional view. Fig. 6 shows a circuit diagram of an embodiment of the bottom bracket gear. Detailed description of embodiments

[0034] Fig. Figure 1 shows a sectional view of a schematic diagram of an embodiment of a shift gate 41, 42, 43, 44 of a shift drum 52 for a bottom bracket transmission. The bottom bracket transmission provides various gear ratios and has a shifting device. Several of the shift gates 41, 42, 43, 44 are arranged on the shift drum 52, and the shifting device can be configured such that when switching to a different gear ratio than the target shifting state, an intermediate shifting state is usually engaged that has a lower gear ratio than the target shifting state. Fig. 1 is described in more detail below.

[0035] Fig. Figure 2 shows a diagram of an embodiment of a planetary roller 10 of a bottom bracket gear. The bottom bracket gear comprises a drive element 1, a switching device, an actuating unit, the planetary roller 10, a stationary component 3 and an output element 2. The stationary component 3 is in this case connected by means of a Fig. 2 not shown shift drum 52 and a housing. The drive element 1, the planetary roller 10 and the output element 2 are arranged coaxially to each other. The actuating unit comprises the shift drum 52. The shift drum 52 is arranged axially parallel to the drive element 1. The drive element 1 is mechanically connected to the output element 2 by means of the planetary roller 10. The drive element 1 can be Fig. 2 can be driven by muscle power and by an electric drive unit.

[0036] The planetary roller 10 has a first planetary gear set 11 with a first sun gear 12, a first planet carrier 13, a number of first planet gears 14, and a first ring gear 15. The planetary roller 10 also has a second planetary gear set 16 with a second sun gear 17, a second planet carrier 18, a number of second planet gears 19, and a second ring gear 20. The planetary roller 10 also has a third planetary gear set 21 with a third sun gear 22, a third planet carrier 23, a number of third planet gears 24, and a third ring gear 25. The planetary roller 10 also has a fourth planetary gear set 26 with a fourth sun gear 27, a fourth planet carrier 28, a number of fourth planet gears 29, and a fourth ring gear 30. One of the sun gears 12, 17, 22, 27, the planet carrier 13, 18, 23, 28 and the ring gears 15, 20, 25, 30 each form a planetary gear set element.Some of the planetary gear set elements may be connected to each other in a rotationally fixed manner.

[0037] The planetary roller 10 further comprises a first one-way clutch F1, a second one-way clutch F2, a third one-way clutch F3, and a fourth one-way clutch F4. Each of the one-way clutches F1, F2, F3, F4 connects two planetary gear set elements to one another in a rotational direction. These two planetary gear set elements are rotatable relative to one another in the opposite direction of rotation. The shifting device comprises a first brake pawl B1, a second brake pawl B2, a third brake pawl B3, and a fourth brake pawl B4, each forming a shifting element. A planetary gear set element can be secured to the stationary component 3 by means of one of the brake pawls B1, B2, B3, B4. Thus, the present planetary roller 10 provides sixteen transmission ratios or gears.

[0038] Fig. 3 shows an embodiment of a shift drum 52. The shift drum 52 has a first shift gate 41, a second shift gate 42, a third shift gate 43, and a fourth shift gate 44. The shift drum 52 also has a locking gate 51. The first shift gate 41 has eight elevations 45, the second shift gate 42 has four elevations 46, the third shift gate 43 has two elevations 47, the fourth shift gate 44 has one elevation 48, and the locking gate 51 has sixteen locking elevations.

[0039] The elevations 45, 46, 47, 48 of the first to fourth switching contours 41, 42, 43, 44 differ in that the tip of an elevation 45, 46, 47, 48 of a switching contour 41, 42, 43, 44 is wider the fewer elevations 45, 46, 47, 48 the respective switching contour 41, 42, 43, 44 has. For example, the tip of the elevation 48 of the fourth switching contour 44 extends in the circumferential direction over almost half the circumference of the fourth switching contour 44. In contrast, the tip of the elevation 45 of the first switching contour 41 extends only very briefly in the circumferential direction. In addition, the elevations 45, 46, 47, 48 of the first to fourth switching contours 41, 42, 43, 44 differ in that a valley between elevations 45, 46, 47, 48 of one of the switching contours 41, 42, 43, 44 is wider, the fewer elevations 45, 46, 47, 48 the respective switching contour 41, 42, 43, 44 has.A rising edge 49 and a falling edge 50 are identical for each elevation 45, 46, 47, 48, regardless of which switching contour 41, 42, 43, 44 the elevation 45, 46, 47, 48 is formed on.

[0040] The first shift gate 41 is in Fig. 3 is arranged on the left side of the shift drum 52. The left side is the left side in the direction of travel, opposite a side on which a chainring or pulley for driving a rear tire of a bicycle is arranged. The second shift gate 42, the third shift gate 43, the locking gate 51, and the fourth shift gate 44 are arranged in this order to the right of the first shift gate 41.

[0041] Fig. 4 shows a sectional view of an embodiment of a bottom bracket transmission. The shift drum 52 is rotatably mounted in the housing with respect to its central axis. The first brake pawl B1, the second brake pawl B2, the third brake pawl B3, and the fourth brake pawl B4 are arranged in this order in the figure from left to right. The first brake pawl B1, the second brake pawl B2, the third brake pawl B3, and the fourth brake pawl B4 are rotatably mounted on the bearing pin 4 with a common axis of rotation. The first brake pawl B1 is in contact with the first shift gate 41. The second brake pawl B2 is in contact with the second shift gate 42. The third brake pawl B3 is in contact with the third shift gate 43. The fourth brake pawl B4 is in contact with the fourth shift gate 44.

[0042] Fig. Figure 5 shows an embodiment of the second brake pawl B2 in a sectional view. It shows a section through the second shift gate 42 with four elevations 46. In this case, all brake pawls B1, B2, B3, and B4 have the same geometric design.

[0043] A protrusion 46 of the second shift gate 42 is moved by rotation of the shift drum 52. If a protrusion 46 hits a pressure piece of the brake pawl B2, i.e. the Fig. 5 lower end of the brake pawl B2, the brake pawl B2 is rotated clockwise around the central axis of the bearing pin 4, which thus forms the axis of rotation of the brake pawl B2. This causes the pawl of the brake pawl B2 to move, i.e. a Fig. 5 upper end of the brake pawl B2, away from the second ring gear 20. When the pressure piece touches the tip of the protrusion 46, the pawl is moved out of the area of ​​the teeth of a locking toothing 31, which is rotationally fixedly connected to the second ring gear 20. The second ring gear 20 can then rotate freely. Thus, by rotating the shift drum 52 in one direction of rotation, a higher gear can be engaged in the bottom bracket transmission. By rotating the shift drum 52 in the opposite direction of rotation, a lower gear can be engaged in the bottom bracket transmission.

[0044] In reverse order, when the pressure piece leaves the peak of the elevation 46 and approaches a depression, the pawl of the brake pawl B2 is moved into the area of ​​the teeth of the locking toothing 31. This causes the brake pawl B2 to rotate counterclockwise. When the pawl makes contact with the teeth of the locking toothing 31, the clockwise rotation of the second ring gear 20 is blocked. The pawl is then coupled to the locking toothing 31, and the second ring gear 20 is fixed for clockwise rotation on the shift drum 52 in the housing.

[0045] In Fig. 1 shows elevations 45, 46, 47, 48 arranged side by side in the direction of rotation. The arrow in Fig. 1 indicates the direction of rotation of the shift drum 52. The direction of rotation points opposite to the direction of rotation of the shift drum 52. The brake pawls B1, B2, B3, B4 move in the direction of rotation along the shift gates 41, 42, 43, 44. The elevations 45, 46, 47, 48 each have a switching reference point that causes one of the brake pawls B1, B2, B3, B4 to switch from a closed state to an open state, or vice versa, as soon as the pressure piece makes contact with the switching reference point. The elevations 45, 46, 47, 48, the shift gates 41, 42, 43, 44, and the switching device are designed such that, in order to achieve the target switching states of the switching elements, the switching elements are closed before the switching elements are opened.

[0046] The elevations 45, 46, 47, 48 have a rising flank 49 and a falling flank 50. Falling flanks 50 and rising flanks 49 are arranged alternately in the direction of rotation. In the present case, the rising flank 49 of one of the elevations 45, 46, 47, 48 of one of the switching gates 41, 42, 43, 44 and the falling flank 50 of one of the elevations 45, 46, 47, 48 of another of the switching gates 41, 42, 43, 44 are arranged in the circumferential direction in such a way that the switching reference point on the falling flank 50 comes into contact with the pressure piece of a brake pawl B1, B2, B3, B4 before the switching reference point of the rising flank 49 comes into contact with the pressure piece of another brake pawl B1, B2, B3, B4.

[0047] In this case, the switching reference point for switching to the closed state is provided on the falling edge 50 near the tip of one of the elevations 45, 46, 47, 48. The switching reference point for switching to the open state is provided on the rising edge 49 near the tip of one of the elevations 45, 46, 47, 48.

[0048] The falling flank 50 of one elevation 45, 46, 47, 48 and the rising flank 49 of another elevation 45, 46, 47, 48 of the same switching contour 41, 42, 43, 44 meet centrally between the two elevations 45, 46, 47, 48. The falling flank 50 and the rising flank 49 form a depression formed by a radius between the falling flank 50 and the rising flank 49. The elevation 45 has a peak formed between the rising flank 49 and the falling flank 50. The peak has an outer contour that is circular and concentric with the rotational axis of the switching drum 52.

[0049] The elevations 45, 46, 47, 48 have a gradient in the circumferential direction that continuously decreases in the radial direction up to their maximum extension. The elevations 45, 46, 47, 48 are designed symmetrically with respect to a radial direction extending from the rotational axis of the shift drum 52 toward the tip.

[0050] Fig. Figure 6 shows a shift diagram of an embodiment of the bottom bracket gear. In this case, the bottom bracket gear has sixteen gears. The first gear V1 has the highest gear ratio. A specific force on the input element 1 results in a force on the output element 2 that is greater than the force on the input element 1. The sixteenth gear V16 has the smallest gear ratio. By means of the sixteenth gear V16, a specific force on the input element 1 results in a force on the output element 2 that is smaller than the force on the input element 1. The speed at the output element 2 increases relative to the speed at the input element 1.

[0051] Fig. 6 shows that the first brake pawl B1, the second brake pawl B2 and the third brake pawl B3 are in the closed state when the planetary roller 10 provides the eighth gear V8. The fourth brake pawl B4, however, is in the open state for the eighth gear V8. For a target switching state of the switching device for the ninth gear V9, the first brake pawl B1, the second brake pawl B2 and the third brake pawl B3 are in the open state. The fourth brake pawl B4, however, is in the closed state. According to the design of the switching contours 41, 42, 43, 44 with the elevations 45, 46, 47, 48, which are described with reference to Fig. As described in Figure 5, when switching to the target switching state V9, the fourth brake pawl B4 is first closed. This achieves an intermediate switching state in which all brake pawls B1, B2, B3, and B4 are in the closed state. This intermediate switching state corresponds to the sixteenth gear V16. The individual planetary gear set elements rotate in a direction in which the first one-way clutch F1, the second one-way clutch F2, the third one-way clutch F3, and the fourth one-way clutch F4 rotate freely.

[0052] By referring to Fig.1, whereby a brake pawl B1, B2, B3, B4 is closed before another brake pawl B1, B2, B3, B4 is opened, an intermediate shift state does not provide a higher gear ratio or a lower gear than the target shift state. For most target shift states, an intermediate shift state provides a lower gear than the target shift state. For the target shift states of gears one to three V1, V2, V3, the fourth gear V4 results as the intermediate shift state. For gears five to seven V5, V6, V7, the eighth gear V8 results as the intermediate shift state. For gears nine to fifteen V9, V10, V11, V12, V13, V14, V15, the sixteenth gear V16 results as the intermediate shift state.

[0053] As a result, the user must apply greater force to the drive element in the intermediate shift state than in the target shift state in order to move the vehicle at a constant speed, for example when climbing a hill. However, the intermediate shift state is only engaged for a very short period of time, so the user hardly notices the increased force required. This prevents a lower gear from being engaged in an intermediate shift state than in the target shift state. A lower gear in an intermediate shift state gives the user the feeling of pedaling the bicycle without any noticeable resistance. This negatively impacts the user's riding experience and riding safety and is avoided with the described embodiment. Reference symbol 1 drive element 2 output element 3 Stationary component 4 bearing bolts 10 planetary roller 11, 16, 21, 26 planetary gear set 12, 17, 22, 27 sun gear 13, 18, 23, 28 planet carriers 14, 19, 24, 29 planetary gear 15, 20, 25, 30 ring gear 31 locking teeth 41 First shift gate 42 Second shift gate 43 Third shift gate 44 Fourth shift gate 45, 46, 47, 48 Survey 49 Rising Flank 50 Falling Edge 51 locking mechanism 52 shift drum B1 First brake pawl B2 Second brake pawl B3 Third brake pawl B4 Fourth brake pawl F1 First freewheel clutch F2 Second overrunning clutch F3 Third overrunning clutch F4 Fourth overrunning clutch QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 220 044 B4

[0002]

Claims

[1] Bottom bracket gear for a vehicle that can be operated with muscle power, wherein the bottom bracket gear comprises a drive element (1), a switching device with switching elements, an actuating unit with switching gates (41, 42, 43, 44), a planetary roller (10) with planetary gear set elements, a stationary component (3) and an output element (2), wherein the drive element (1) is mechanically operatively connected to the output element (2) by means of the planetary roller (10), at least two planetary gear set elements can be fixed to the stationary component (3) by closing one of the switching elements, one of the planetary gear set elements is formed by a sun gear (12, 17, 22, 27), a planet carrier (13, 18, 23, 28) or a ring gear (15, 20, 25, 30), the switching gates (41, 42, 43, 44) are mechanically connected to the switching elements by means of the switching device in such a way that the switching elements can be switched between an open and a closed switching state by adjusting the actuating unit, the planetary roller (10) provides different gear ratios by means of a combination of switching states of the switching elements, and the actuating unit and the switching device are arranged such that, before at least one target switching state of the switching elements is reached, an intermediate switching state is engaged which sets a transmission ratio in the planetary roller (10) which is smaller than the transmission ratio in the target switching state. [2] Bottom bracket gear according to claim 1, characterized bythat the switching gates (41, 42, 43, 44) are arranged relative to one another and the switching gates (41, 42, 43, 44) and the switching elements are designed in such a way that an adjustment of the actuating unit causes a coordinated opening and closing of the switching elements. [3] Bottom bracket gear according to claim 2, characterized by that in order to achieve at least one target switching state of the switching elements, switching elements are closed before switching elements are opened. [4] Bottom bracket gear according to claim 1-3, characterized by , that the actuating unit has at least two switching gates (41, 42, 43, 44) each with at least one elevation (45, 46, 47, 48), wherein the switching gates (41, 42, 43, 44) are rotatably mounted with respect to their central axes, and one of the elevations (45, 46, 47, 48) causes one of the switching elements to switch over by means of a rotation of one of the switching gates (41, 42, 43, 44). [5] Bottom bracket gear according to claim 4, characterized by , that the elevation (45, 46, 47, 48) has a rising flank (49) and a falling flank (50), and the rising flank (49) and the falling flank (50) meet between two elevations (45, 46, 47, 48) of a switching gate (41, 42, 43, 44). [6] Bottom bracket gear according to claim 5, characterized by , that the rising edge (49) and the falling edge (50) each have a switching reference point which, when contacted with the switching device, causes the switching of a switching element, and touching the switching reference point of the falling edge (50) causes one of the switching elements to close. [7] Bottom bracket gear according to one of claims 2-6, characterized by , that the number of elevations (45, 46, 47, 48) of a switching gate (41, 42, 43, 44) according to the formula N=2 s-adepends on the number of existing switching gates (41, 42, 43, 44) and is different for each switching gate (41, 42, 43, 44), whereby “N” is the number of elevations (45, 46, 47, 48) of a switching gate (41, 42, 43, 44), “s” is the number of switching gates (41, 42, 43, 44), and “a” is a consecutive integer number of a switching gate (41, 42, 43, 44) and 1 ≤ a ≤ s. [8] Bottom bracket gear according to one of claims 2-7, characterized by that the elevation (45, 46, 47, 48) has a gradient in the circumferential direction which continuously decreases up to its maximum extension in the radial direction. [9] Bottom bracket gear according to one of the preceding claims, characterized bythat the switching elements are formed by brake pawls (B1, B2, B3, B4) which are rotatably mounted, extend in a longitudinal direction, can be in contact with a switching gate (41, 42, 43, 44) at one end in the longitudinal direction, and have a pawl at the other end in the longitudinal direction which can be coupled to one of the planetary gear set elements. [10] Bottom bracket gear according to claim 9, characterized by that several brake pawls (B1, B2, B3, B4) are rotatably mounted around a common axis of rotation. [11] Bottom bracket gear according to one of claims 9 to 10, characterized by , that the switching device comprises a first brake pawl (B1), a second brake pawl (B2), a third brake pawl (B3) and a fourth brake pawl (B4), the planetary roller (10) comprises a first planetary gear set (11) with a first sun gear (12), a first planetary carrier (13) and a first ring gear (15), a second planetary gear set (16) with a second sun gear (17), a second planetary carrier (18) and a second ring gear (20), a third planetary gear set (21) with a third sun gear (22), a third planetary carrier (23) and a third ring gear (25), and a fourth planetary gear set (26) with a fourth sun gear (27), a fourth planetary carrier (28) and a fourth ring gear (30), a first one-way clutch (F1), a second one-way clutch (F2), a third one-way clutch (F3) and a fourth one-way clutch (F4), the actuating unit has a first switching gate (41), a second switching gate (42), a third switching gate (43) and a fourth switching gate (44), each with at least one elevation (45, 46, 47, 48), and the first one-way clutch (F1) is locked when the first brake pawl (B1) is open, the second one-way clutch (F2) is locked when the second brake pawl (B2) is open, the third one-way clutch (F3) is locked when the third brake pawl (B3) is open and the fourth one-way clutch (F4) is locked when the fourth brake pawl (B4) is open. [12] Bottom bracket gear according to one of the preceding claims, characterized by that the actuating unit has a locking gate (51) for locking the switching gates (41, 42, 43, 44) in predetermined angular positions. [13] Bottom bracket gear according to one of the preceding claims, characterized by that the actuating unit has a common shift drum (52) which forms the shift gates (41, 42, 43, 44). [14] Bicycle or pedelec with a bottom bracket gear according to one of the preceding claims, which is driven by a drive device and drives an output device.

Images