CROSS-REFERENCE TO RELATED APPLICATION

The present application is related and has right of priority to German Patent Application No. 10 2023 204 592.3 filed on May 17, 2023, the entirety of which is incorporated by reference for all purposes.

FIELD OF THE INVENTION

The present invention relates generally to a bottom bracket planetary gear mechanism for a bicycle or a pedelec with a gear mechanism input shaft as drive and a gear mechanism output shaft as output, with a multi-step main gear mechanism and with at least one gear mechanism shifting group. Furthermore, the invention relates generally to a bicycle or pedelec with the bottom bracket gear mechanism.

BACKGROUND

For example, document DE 10 2018 208 380 A1 has disclosed a 16-gear bottom bracket gear mechanism of planetary design for a bicycle or a pedelec with a four-gear main gear mechanism which is assigned a front-mounted gear set and a rear-mounted gear set each with two gear stages.

SUMMARY OF THE INVENTION

The present invention is directed to a bottom bracket gear mechanism, and a bicycle or pedelec with such bottom bracket gear mechanism, where the bottom bracket gear mechanism has as little structural complexity as possible with properties which are improved in comparison with the prior art.

A bottom bracket planetary gear mechanism for a bicycle or a pedelec is proposed. The gear mechanism includes a gear mechanism input shaft as a drive, a gear mechanism output shaft as an output, a multi-step main gear mechanism, and at least one gear mechanism shifting group. The gear mechanism shifting group has two planetary gear sets including a first planetary gear set and a second planetary gear set. The gear mechanism shifting group also has three shifting elements, including a first shifting element, a second shifting element, and a fifth shifting element. A second element of a first planetary gear set is connected to the first shaft, a first element of the first planetary gear set is connected via a fourth shaft to a first element of the second planetary gear set, and a third element of the first planetary gear set is fixable via a second shaft and via a first shifting element as a brake. The third element of the first planetary gear set is connected via the second shaft to a second element of the second planetary gear set. A third element of the second planetary gear set is fixable via a third shaft and a second shifting element as a brake. A fifth shifting element as a clutch or freewheel is provided to block the first planetary gear set and the second planetary gear set in order to connect two of the four shafts, and in each case, at least two of the six elements of the two planetary gear sets to one another.

By way of the above-described attachment of the gear mechanism shifting group, a particularly simple and compact construction in the bottom bracket gear mechanism is realized in the case of the proposed bottom bracket gear mechanism with only two provided planetary gear sets and only three provided shifting elements in the case of the gear mechanism shifting group. This is accompanied by particularly low component loads and an advantageously high degree of toothing efficiency on account of the geometric transmission ratio in the case of the bottom bracket gear mechanism.

For the mechanical connection of elements of the two planetary gear sets in the case of the gear mechanism shifting group, only four further shafts or shaft-like elements are preferably used in addition to drive and output, where the term “shaft” is not to be understood as exclusively meaning a cylindrical, rotatably mounted machine element for the transmission of torques, but rather general connecting elements which connect the individual gear set elements to one another for the transmission of torque are also to be understood by this.

The axial sequence of main gear mechanism and gear mechanism shifting group are swappable in the case of the proposed bottom bracket gear mechanism. Accordingly, the gear mechanism shifting group is connected upstream or downstream of the main gear mechanism between the gear mechanism input shaft and the gear mechanism output shaft. In the case of the gear mechanism shifting group being arranged connected upstream, a pedal crank, connected to the gear mechanism input shaft, of the bottom bracket gear mechanism is connected to the first shaft as it were as gear mechanism input shaft of the gear mechanism shifting group, and the fourth shaft of the gear mechanism shifting group is connected on the input side to the multi-step main gear mechanism. It is possible that the gear mechanism input shaft and the first shaft are configured in one part or in multiple parts. In the case of the gear mechanism shifting group being arranged connected downstream, the first shaft is connected on the output side to the main gear mechanism, and the fourth shaft of the gear mechanism shifting group is connected to the gear mechanism output shaft. It is possible that the gear mechanism output shaft and the fourth shaft are configured in one part or in multiple parts.

In order to block the two planetary gear sets in the case of the gear mechanism shifting group of the proposed bottom bracket gear mechanism, in each case two of the four provided shafts are connectable to one another via the fifth shifting element in order to connect at least two elements of the planetary gear sets, with the result that, by different arrangement variants of the fifth shifting element, six blocking variants of identical action are possible. For example, the third shaft, in the case of a first arrangement variant of the fifth shifting element, is connectable as a first blocking variant to the fourth shaft. It is also possible that the second shaft, in the case of a second arrangement variant of the fifth shifting element, is connectable as a second blocking variant to the fourth shaft. Furthermore, the second shaft, in the case of a third arrangement variant of the fifth shifting element, is connectable as a third blocking variant to the third shaft. In addition, it is possible that the first shaft, in the case of a fourth arrangement variant of the fifth shifting element, is connectable as a fourth blocking variant to the second shaft. As a fifth blocking variant, the first shaft, in the case of a fifth arrangement variant of the fifth shifting element, is connectable to the fourth shaft. Finally, the first shaft, in the case of a sixth arrangement variant of the fifth shifting element, is connectable as a sixth blocking variant to the third shaft.

In the case of the proposed bottom bracket gear mechanism, a multi-step main gear mechanism of any desired configuration of planetary design with at least one further planetary gear set and at least two further shifting elements is used. The main gear mechanism is preferably a four-gear gear mechanism, and accordingly has two further planetary gear sets, namely a third and fourth planetary gear set with four further shifting elements.

Within the context of a first embodiment of the main gear mechanism, a second element of the fourth planetary gear set is connected to the gear mechanism input shaft or to the fourth shaft of the gear mechanism shifting group, a first element of the fourth planetary gear set is connected to a second element of the third planetary gear set, and a third element of the fourth planetary gear set is connected to the gear mechanism output shaft or to the first shaft of the gear mechanism shifting group. A first element of the third planetary gear set is fixable via a third shifting element as a brake, and is connectable to the gear mechanism input shaft or to the fourth shaft of the gear mechanism shifting group via a sixth shifting element as a clutch or freewheel. A third element of the third planetary gear set is fixable via a fourth shifting element as a brake, and is connectable to the gear mechanism output shaft or to the first shaft of the gear mechanism shifting group via a seventh shifting element as a clutch or freewheel.

Within the context of a second embodiment of the main gear mechanism, a second element of the third planetary gear set is connected to the gear mechanism input shaft or to the fourth shaft of the gear mechanism shifting group, a first element of the third planetary gear set is connected to a second element of the fourth planetary gear set, and a third element of the third planetary gear set is connected to the gear mechanism output shaft or to the first shaft of the gear mechanism shifting group. A third element of the fourth planetary gear set is fixable via a fourth shifting element as a brake, and is connectable to the gear mechanism input shaft or to the fourth shaft of the gear mechanism shifting group via a seventh shifting element as a clutch or freewheel. A first element of the fourth planetary gear set is fixable via a third shifting element as a brake, and is connectable to the gear mechanism output shaft or to the first shaft of the gear mechanism shifting group via a sixth shifting element as a clutch or freewheel.

One preferred embodiment of the invention provides that at least one of the provided planetary gear sets is a minus planetary gear set, which results in an arrangement which is particularly favorable in terms of installation space. It is also conceivable that one of the planetary gear sets is a plus planetary gear set.

A minus planetary gear set is preferably transferrable into a plus planetary gear set if the planetary gear carrier attachment and ring gear attachment on this gear set are swapped with one another, and the magnitude of the stationary gear ratio is increased by 1. On its planetary carrier, a minus planetary gear set has rotatably mounted planetary gears which mesh with the sun gear and the ring gear of this planetary gear set, with the result that, in the case of a fixed planetary gear carrier and a rotating sun gear, the ring gear rotates in an opposite direction to the sun gear rotational direction. On its planetary gear carrier, a plus planetary gear set has rotatably mounted inner and outer planetary gears which are in tooth engagement with one another, the sun gear of this planetary gear set meshing with the inner planetary gears, and the ring gear of this planetary gear set meshing with the outer planetary gears, with the result that, in the case of a fixed planetary gear carrier and a rotating sun gear, the ring gear rotates in a rotational direction which is identical to the sun gear rotational direction.

For a person skilled in the art, this means that, for an individual gear set that is a minus planetary gear set, the first element or gear set element is a sun gear, the second element is a planetary gear carrier or spider, and the third element is a ring gear. Furthermore, this means that, for an individual gear set which is a plus planetary gear set, the first element is a sun gear, the second element is a ring gear, and the third element is a planetary gear carrier or spider.

Furthermore, it is conceivable in the case of the proposed bottom bracket gear mechanism that multi-step planets are used both in the case of a minus planetary gear set and in the case of a plus planetary gear set. In the case of a minus multi-step planetary gear set, the assignment of the elements or the gear set elements is maintained as in the case of a conventional minus planetary gear set. In the case of a plus multi-step planetary gear set, it is provided that the first element is a first sun gear, the second element is a second sun gear and the third element is a planetary gear carrier, or that the first element is a first ring gear, the second element is a second ring gear, and the third element is a planetary gear carrier.

Within the context of the present invention, it is provided in the case of the proposed bottom bracket gear mechanism with the main gear mechanism and the gear mechanism shifting group that the first shifting element, the second shifting element, the third shifting element and the fourth shifting element are each a positively locking brake, and that the fifth shifting element, sixth shifting element and the seventh shifting element are each a freewheel.

The shifting elements which are brakes are preferably positively locking shifting elements, for example inexpensive shifting claws or the like, for example with a toothed brake ring and a corresponding shifting pawl. Brakes as shifting elements have the advantage that they are readily reached from the outside for actuation. Since the provided freewheels are used as clutches, it is advantageous if the brakes are, for example, brakes which act on one side, in order to prevent blocking of the gear mechanism in the case of a rotational directional reversal at the drive or at the output. Non-actively switchable or actuable freewheels are preferably used as freewheels. This has the advantage that no switching actuation is required in the case of the passive switching elements. The non-actuable freewheel transmits a torque when it locks in the locking direction state. In the opposite rotational direction, no torque is transmitted, since the freewheel does not lock in the overrunning drive state. It is conceivable, however, that actively switchable freewheels or else actively switchable freewheel brakes are also used.

In order to further optimize the actuation of the proposed bottom bracket gear mechanism, it is provided that at least one torque sensor or the like is provided on the drive and/or on the output.

In order to electrically assist the drive in the case of the proposed bottom bracket gear mechanism, at least one electric machine or the like is connected or connectable or couplable fixedly or releasably to the drive or to the pedal crank shaft or gear mechanism input shaft and/or to the output or to the gear mechanism output shaft. The electric machine is preferably axially parallel to the pedal crank shaft or gear mechanism input shaft, while the planetary gear sets are arranged coaxially with respect to the pedal crank shaft or gear mechanism input shaft.

A further aspect of the present invention claims a bicycle or pedelec with the above-described bottom bracket gear mechanism. This results in the advantages which have already been described and further advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following text, the present invention will be explained further on the basis of the drawings, in which:

FIG. 1 shows a diagrammatic or schematic outline view of a first embodiment of a bottom bracket gear mechanism according to the invention on a bicycle or a pedelec with a gear mechanism shifting group which is connected downstream of a main gear mechanism, with a first blocking variant in the case of the first two planetary gear sets;

FIG. 2 shows a diagrammatic outline view of a second embodiment of the bottom bracket gear mechanism with the gear mechanism shifting group which is connected upstream of the main gear mechanism, with the first blocking variant in the case of the first two planetary gear sets;

FIG. 3 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a second blocking variant in the case of the first two planetary gear sets;

FIG. 4 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a third blocking variant in the case of the first two planetary gear sets;

FIG. 5 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a fourth blocking variant in the case of the first two planetary gear sets;

FIG. 6 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a fifth blocking variant in the case of the first two planetary gear sets;

FIG. 7 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a sixth blocking variant in the case of the first two planetary gear sets;

FIG. 8 shows a shifting pattern with the three shiftable gears of the gear mechanism shifting group in the case of the bottom bracket gear mechanism;

FIG. 9 shows a diagrammatic outline view of a planetary gear set as a minus planetary gear set;

FIG. 10 shows a diagrammatic outline view of a planetary gear set as a plus planetary gear set;

FIG. 11 shows a diagrammatic outline view of a planetary gear set as a minus multi-step planetary gear set;

FIG. 12 shows a diagrammatic outline view of a planetary gear set as a plus multi-step planetary gear set with two sun gears;

FIG. 13 shows a diagrammatic outline view of a planetary gear set as a plus multi-step planetary gear set with two ring gears;

FIG. 14 shows a diagrammatic outline view of the bottom bracket gear mechanism with a first embodiment of the main gear mechanism, as four-gear gear mechanism, which is connected upstream of the gear mechanism shifting group;

FIG. 15 shows a diagrammatic outline view of the bottom bracket gear mechanism with planetary gear sets which are swapped in an axial sequence in the case of the first embodiment of the main gear mechanism, as four-gear gear mechanism, which is connected upstream of the gear mechanism shifting group;

FIG. 16 shows a diagrammatic outline view of the bottom bracket gear mechanism with a second embodiment of the main gear mechanism, as four-gear gear mechanism, which is connected upstream of the gear mechanism shifting group;

FIG. 17 shows a shifting pattern of the bottom bracket gear mechanism according to FIGS. 14-16;

FIG. 18 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 1 with a torque sensor (indicated by way of example) at the drive;

FIG. 19 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 18 with an electric machine which is arranged by way of example at the drive;

FIG. 20 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 18 with an electric machine which is arranged by way of example at the output; and

FIG. 21 shows a diagrammatic outline view of the bottom bracket gear mechanism according to FIG. 18 with a freewheel which is provided between the pedal crank shaft and the gear mechanism input shaft.

DETAILED DESCRIPTION

Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

FIGS. 1-21 show different design variants or embodiments, or shifting patterns of a bottom bracket gear mechanism according to the invention of planetary design, merely by way of example. FIG. 1 shows by way of example a bicycle or pedelec 1 (indicated merely diagrammatically) with the bottom bracket gear mechanism.

The bottom bracket gear mechanism is shown in a housing or bottom bracket housing 2 with a pedal crank shaft or pedal crank with pedals, the pedal crank shaft being connected to a gear mechanism input shaft WAn. Furthermore, the bottom bracket gear mechanism includes a gear mechanism output shaft WAb as output with a chain sprocket or belt pulley (not shown further). Furthermore, a multi-step main gear mechanism 3 and a gear mechanism shifting group 4 are provided. The gear mechanism shifting group 4 has a first planetary gear set RS1 and a second planetary gear set RS2, and three shifting elements B1, B2, K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI. The main gear mechanism 3 and the gear mechanism shifting group 4 form two sub-gear mechanisms.

Independently of the respective embodiments, it is provided that a second element of a first planetary gear set RS1 is connected to a first shaft W1, with the first shaft W1 being connected to the gear mechanism input shaft WAn when the gear mechanism shifting group 4 is connected upstream or being connected on the output side to the main gear mechanism 3 when the gear mechanism shifting group 4 is connected downstream. A first element of the first planetary gear set RS1 is connected via a fourth shaft W4 to a first element of the second planetary gear set RS2, with the fourth shaft W4 being connected to the gear mechanism output shaft WAb in the case of a downstream connected gear mechanism shifting group 4 or being connected on the input side to the main gear mechanism 3 in the case of an upstream connected gear mechanism shifting group 4. A third element of the first planetary gear set RS1 is fixable on the housing 2 via a second shaft W2 and via a first shifting element B1 which is a brake, with the third element of the first planetary gear set RS1 being connected via the second shaft W2 to a second element of the second planetary gear set RS2. A third element of the second planetary gear set RS2 is fixable on the housing 2 via a third shaft W3 and a second shifting element B2 which is a brake. A fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, which is a clutch or freewheel, for connecting two of the four shafts W1, W2, W3, W4 is provided to block the first planetary gear set RS1 and the second planetary gear set RS2.

In FIGS. 1-7, each of the two provided planetary gear sets RS1, RS2 is a minus planetary gear set, where minus planetary gear sets are favorable in terms of installation space. It is provided that in each case, a sun gear SR1, SR2 is provided as the first element, a planetary gear carrier PT1, PT2 is provided as the second element, and a ring gear HR1, HR2 is provided as the third element of the planetary gear sets RS1, RS2.

FIG. 1 shows a first embodiment of the bottom bracket gear mechanism, in the case of which the gear mechanism shifting group 4 is connected downstream of the multi-step main gear mechanism 3, and a first blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 is shown, in which the third shaft W3 is connectable to the fourth shaft W4 in the case of a first arrangement variant of the fifth shifting element K1^I.

In detail, it is provided in the case of the first embodiment according to FIG. 1 that the planetary gear carrier PT1 of the first planetary gear set RS1 is connected to the first shaft W1 which is connected on the output side to the main gear mechanism 3, that the sun gear SR1 of the first planetary gear set RS1 is connected via the fourth shaft W4 to the sun gear SR2 of the second planetary gear set RS2, that the fourth shaft W4 is connected to the gear mechanism output shaft WAb, that the ring gear HR1 of the first planetary gear set RS1 is fixable on the housing 2 via the second shaft W2 and via the first shifting element B1 which is a brake, that the ring gear HR1 of the first planetary gear set RS1 is connected via the second shaft W2 to the planetary gear carrier PT2 of the second planetary gear set RS2, that the ring gear HR2 of the second planetary gear set RS2 is fixable on the housing 2 via the third shaft W3 and the second shifting element B2 which is a brake, and that, within the context of a first blocking variant, the ring gear HR2 of the second planetary gear set RS2 is connectable via the fifth shifting element K1^Iin the first arrangement variant to the sun gear SR2 of the second planetary gear set RS2 and to the sun gear SR1 of the first planetary gear set RS1.

FIG. 2 shows a second embodiment of the bottom bracket gear mechanism, in the case of which the gear mechanism shifting group 4 is connected upstream of the multi-step main gear mechanism 3, the first blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 is also shown.

In detail, it is provided in the case of the second embodiment according to FIG. 2 that the planetary gear carrier PT1 of the first planetary gear set RS1 is connected via the first shaft 1 or directly to the gear mechanism input shaft Wan, that the sun gear SR1 of the first planetary gear set RS1 is connected via the fourth shaft W4 to the sun gear SR2 of the second planetary gear set RS2, that the fourth shaft W4 is connected on the input side to the main gear mechanism 3, that the ring gear HR1 of the first planetary gear set RS1 is fixable on the housing 2 via the second shaft W2 and via the first shifting element B1 which is a brake, that the ring gear HR1 of the first planetary gear set RS1 is connected via the second shaft W2 to the planetary gear carrier PT2 of the second planetary gear set RS2, that the ring gear HR2 of the second planetary gear set RS2 is fixable on the housing 2 via the third shaft W3 and the second shifting element B2 which is a brake, and that, within the context of a first blocking variant, the ring gear HR2 of the second planetary gear set RS2 is connectable via the fifth shifting element K1^Iin the first arrangement variant to the sun gear SR2 of the second planetary gear set RS2 and to the sun gear SR1 of the first planetary gear set RS1.

FIG. 3 shows a second blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 by way of example on the basis of the first embodiment of the bottom bracket gear mechanism, in the case of which, in the case of a second arrangement variant of the fifth shifting element K1^II, the second shaft W2 is connectable to the fourth shaft W4. In detail, the result is that, within the context of the second blocking variant, the ring gear HR1 of the first planetary gear set RS1 and the planetary gear carrier PT2 of the second planetary gear set RS2 are connectable via the fifth shifting element K1^IIin the second arrangement variant to the sun gear SR2 of the second planetary gear set RS2 and to the sun gear SR1 of the first planetary gear set RS1.

FIG. 4 shows a third blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 by way of example on the basis of the first embodiment of the bottom bracket gear mechanism, in the case of which, in the case of a third arrangement variant of the fifth shifting element K1^III, the second shaft W2 is connectable to the third shaft W3. In detail, the result is that, within the context of the third blocking variant, the ring gear HR2 of the second planetary gear set RS2 is connectable via the fifth shifting element K1^IIIin the third arrangement variant to the planetary gear carrier PT2 of the second planetary gear set RS2 and the ring gear HR1 of the first planetary gear set RS1.

FIG. 5 shows a fourth blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 by way of example on the basis of the first embodiment of the bottom bracket gear mechanism, in the case of which, in the case of a fourth arrangement variant of the fifth shifting element K1^IV, the first shaft W1 is connectable to the second shaft W2. In detail, the result is that, within the context of the fourth blocking variant, the planetary gear carrier PT1 of the first planetary gear set RS1 is connectable via the fifth shifting element K1^IVin the fourth arrangement variant to the ring gear HR1 of the first planetary gear set RS1 and to the planetary gear carrier PT2 of the second planetary gear set RS2.

FIG. 6 shows a fifth blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 by way of example on the basis of the first embodiment of the bottom bracket gear mechanism, in the case of which, in the case of a fifth arrangement variant of the fifth shifting element K1^V, the first shaft W1 is connectable to the fourth shaft W4. In detail, the result is that, within the context of the fifth blocking variant, the sun gear SR1 of the first planetary gear set RS1 and the sun gear SR2 of the second planetary gear set RS2 are connectable via the fifth shifting element K1^Vin the fifth arrangement variant to the planetary gear carrier PT1 of the first planetary gear set RS1.

FIG. 7 shows a sixth blocking variant of the two planetary gear sets RS1 and RS2 in the case of the gear mechanism shifting group 4 by way of example on the basis of the first embodiment of the bottom bracket gear mechanism, in the case of which, in the case of a sixth arrangement variant of the fifth shifting element K1^VI, the first shaft W1 is connectable to the third shaft W3. In detail, the result is that, within the context of the sixth blocking variant, the planetary gear carrier PT1 of the first planetary gear set RS1 is connectable via the fifth shifting element K1^VIin the sixth arrangement variant to the ring gear HR2 of the second planetary gear set RS2.

FIG. 8 shows a shifting pattern for the gear mechanism shifting group 4 as a three-gear gear mechanism. The result of this is that three gears V1, V2, V3 are realized by way of the gear mechanism shifting group. The shifting elements B1, B2, K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIused for the respective gear V1, V2, V3 are indicated in the shifting pattern. Here, an “X” at the freewheel K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIas a shifting element in the shifting pattern means that the freewheel locks. This functions automatically without external actuation. Furthermore, an “X” at a brake B1, B2 as a shifting element in the shifting pattern means that the brake B1, B2 is closed. This functions via a suitable actuator system.

In detail, the result from the shifting pattern according to FIG. 8 is that, in order to shift a first gear V1, the first shifting element B1 as a brake and the second shifting element B2 as a brake are open, and the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, which is a freewheel, locks. In order to shift a second gear V2, the first shifting element B1 as a brake is open and the second shifting element B2 as a brake is closed, and the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, which is a freewheel, is not locking. In order to shift a third gear V3, the first shifting element B1 as a brake is closed and the second shifting element B2 as a brake is open, and the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, which is a freewheel, is not locking.

FIG. 9 shows by example a minus planetary gear set, in the case of which the first element is a sun gear 1-SR, the second element is a planetary gear carrier 2-PT, and the third element is a ring gear 3-HR.

FIG. 10 shows by example a plus planetary gear set, in the case of which the first element is a sun gear 1-SR, the second element is a ring gear 2-HR, and the third element is a planetary gear carrier 3-PT.

FIG. 11 shows by example a minus multi-step planetary gear set, in the case of which the first element is a sun gear 1-SR, the second element is a planetary gear carrier 2-PT, and the third element is a ring gear 3-HR.

FIG. 12 shows by example a plus multi-step planetary gear set, in the case of which the first element is a first sun gear 1-SRA, the second element is a second sun gear 2-SRB, and the third element is a planetary gear carrier 3-PT.

FIG. 13 shows by example a further embodiment of a plus multi-step planetary gear set, in the case of which the first element is a first ring gear 1-HRA, the second element is a second ring gear 2-HRB, and the third element is a planetary gear carrier 3-PT.

The possible embodiments which are shown in FIGS. 9-13 on the basis of a planetary gear set are transferrable to the specific planetary gear sets RS1, RS2, RS3, RS4 of the bottom bracket gear mechanism according to the invention.

FIGS. 14-16 show by example two different embodiments of the main gear mechanism 3, as a four-gear gear mechanism, which is connected upstream of the gear mechanism shifting group 4. It is readily possible, however, that the main gear mechanism 3 is connected downstream of the gear mechanism shifting group 4. The main gear mechanism 3 preferably includes a third planetary gear set RS3 and a fourth planetary gear set RS4, and four shifting elements B3, B4, K2, K3.

The two illustrations of a first embodiment according to FIG. 14 and according to FIG. 15 differ merely in that the axial sequence of the third planetary gear set RS3 and the fourth planetary gear set RS4 are swapped.

In the case of the first and second embodiment of the main gear mechanism 3 according to FIGS. 14-16, each of the provided planetary gear sets RS1, RS2, RS3, RS4 of the main gear mechanism 3 and the gear mechanism shifting group 4 in the proposed bottom bracket gear mechanism is configured as a minus planetary gear set, which is favorable in terms of installation space. It is provided here that in each case, a sun gear SR1, SR2, SR3, SR4 is the first element, a planetary gear carrier PT1, PT2, PT3, PT4 is the second element, and a ring gear HR1, HR2, HR3, HR4 is the third element of each of the planetary gear sets RS1, RS2, RS3, RS4.

In the case of the first embodiment of the main gear mechanism according to FIGS. 14-15, it is provided in detail that a planetary gear carrier PT4 of the fourth planetary gear set RS4 is connected to the gear mechanism input shaft WAn, that a sun gear SR4 of the fourth planetary gear set RS4 is connected via a seventh shaft W7 to a planetary gear carrier PT3 of the third planetary gear set RS3, that a ring gear HR4 of the fourth planetary gear set RS4 is connected to the first shaft W1 of the gear mechanism shifting group 4, that a sun gear SR3 of the third planetary gear set RS3 is fixable on the housing 2 via a fifth shaft W5 and via a third shifting element B3 which is a brake, and the sun gear SR3 of the third planetary gear set RS3 is connectable via a sixth shifting element K2 which is a clutch or freewheel to the gear mechanism input shaft WAn. A ring gear HR3 of the third planetary gear set RS3 is fixable on the housing 2 via a sixth shaft W6 and via a fourth shifting element B4 which is a brake, and the ring gear HR3 of the third planetary gear set RS3 is connectable via a seventh shifting element K3 which is a clutch or freewheel to the first shaft W1 of the gear mechanism shifting group 4. The attachments of the first and second planetary gear sets RS1, RS2 of the gear mechanism shifting group 4 have already been described.

In the case of the second embodiment of the main gear mechanism 3 according to FIG. 16, it is provided in detail that the planetary gear carrier PT3 of the third planetary gear set RS3 is connected to the gear mechanism input shaft WAn, that the sun gear SR3 of the third planetary gear set RS3 is connected via an eighth shaft W8 to the planetary gear carrier PT4 of the fourth planetary gear set RS4, that the ring gear HR3 of the third planetary gear set RS3 is connected to the first shaft W1 of the gear mechanism shifting group 4, that the ring gear HR4 of the fourth planetary gear set RS4 is fixable on the housing 2 via a seventh shaft W7 and via a fourth shifting element B4 which is a brake, and the ring gear HR4 of the fourth planetary gear set RS4 is connectable to the gear mechanism input shaft WAn via a seventh shifting element K3 which is a clutch or freewheel. The sun gear SR4 of the fourth planetary gear set RS4 is fixable on the housing 2 via a sixth shaft W6 and via a third shifting element B3 which is a brake, and the sun gear SR4 of the fourth planetary gear set RS4 is connectable via a sixth shifting element K2 which is a clutch or freewheel to the first shaft W1 of the gear mechanism shifting group 4. The attachments of the first and second planetary gear sets RS1, RS2 of the gear mechanism shifting group 4 have already been described.

FIG. 17 shows by example a shifting pattern for the embodiments of the bottom bracket gear mechanism according to the invention which are shown in FIGS. 14-16. The fact that the gear mechanism shifting group 4 has three gears and the main gear mechanism 4 has four gears results in a total of 3×4=12 shiftable gears G1 to G12. The shifting elements B1, B2, B3, B4, K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, K2, K3 used for the respective gear G1 to G12 are specified in the shifting pattern. Here, an “X” in the case of a freewheel K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VI, K2, K3 as a shifting element in the shifting pattern means that the freewheel locks. This functions automatically without external actuation. Furthermore, an “X” in the case of a brake B1, B2, B3, B4 as a shifting element in the shifting pattern means that the brake B1, B2, B3, B4 is closed. This functions via a suitable actuator system.

In detail, the result from the shifting pattern according to FIG. 17 is that, in order to realize a first gear G1, the first shifting element B1 which is a brake, the second shifting element B2 which is a brake, the third shifting element B3 which is a brake, and the fourth shifting element B4 which is a brake are all open, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel, the sixth shifting element K2 which is a freewheel, and the seventh shifting element K3 which is a freewheel, are all locking. In order to realize a second gear G2, the first shifting element B1 which is a brake, the second shifting element B2 which is a brake, and the fourth shifting element B4 which is a brake are all open, the third shifting element B3 which is a brake is closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the seventh shifting element K3 which is a freewheel are each locking, and the sixth shifting element K2 which is a freewheel is not locking. In order to realize a third gear G3, the first shifting element B1 which is a brake, the second shifting element B2 which is a brake, and the third shifting element B3 which is a brake are all open, the fourth shifting element B4 which is a brake is closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the sixth shifting element K2 which is a freewheel are locking, and the seventh shifting element K3 which is a freewheel is not locking. In order to realize a fourth gear G4, the first shifting element B1 which is a brake and the second shifting element B2 which is a brake are open, the third shifting element B3 which is a brake and the fourth shifting element B4 which is a brake are both closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel is locking, and the sixth shifting element K2 which is a freewheel and the seventh shifting element K3 which is a freewheel are not locking. In order to realize a fifth gear G5, the first shifting element B1 which is a brake, the third shifting element B3 which is a brake, and the fourth shifting element B4 which is a brake are all open, the second shifting element B2 which is a brake is closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel is not locking, and the sixth shifting element K2 which is a freewheel and the seventh shifting element K3 which is a freewheel are both locking. In order to realize a sixth gear G6, the first shifting element B1 which is a brake and the fourth shifting element B4 which is a brake are both open, the second shifting element B2 which is a brake and the third shifting element B3 which is a brake are both closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the sixth shifting element K2 which is a freewheel are both not locking, and the seventh shifting element K3 which is a freewheel is locking. In order to realize a seventh gear G7, the first shifting element B1 which is a brake and the third shifting element B3 which is a brake are both open, the second shifting element B2 which is a brake and the fourth shifting element B4 which is a brake are both closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the seventh shifting element K3 which is a freewheel are both not locking, and the sixth shifting element K2 which is a freewheel is locking. In order to realize an eighth gear G8, the first shifting element B1 which is a brake is open, the second shifting element B2 which is a brake, the third shifting element B3 which is a brake, and the fourth shifting element B4 which is a brake are closed, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel, the sixth shifting element K2 which is a freewheel, and the seventh shifting element K3 which is a freewheel are not locking. In order to realize a ninth gear G9, the first shifting element B1 which is a brake is closed, the second shifting element B2 which is a brake, the third shifting element B3 which is a brake, and the fourth shifting element B4 which is a brake are open, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel is not locking, and the sixth shifting element K2 which is a freewheel and the seventh shifting element K3 which is a freewheel are both locking. In order to realize a tenth gear G10, the first shifting element B1 which is a brake, and the third shifting element B3 which is a brake are closed, the second shifting element B2 which is a brake, and the fourth shifting element B4 which is a brake are open, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the sixth shifting element K2 which is a freewheel are not locking, and the seventh shifting element K3 which is a freewheel is locking. In order to realize an eleventh gear G11, the first shifting element B1 which is a brake, and the fourth shifting element B4 which is a brake are closed, the second shifting element B2 which is a brake, and the third shifting element B3 which is a brake are open, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel and the seventh shifting element K3 which is a freewheel are not locking, and the sixth shifting element K2 which is a freewheel is locking. In order to realize a twelfth gear G12, the first shifting element B1 which is a brake, the third shifting element B3 which is a brake, and the fourth shifting element B4 which is a brake are closed, the second shifting element B2 which is a brake is open, the fifth shifting element K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIwhich is a freewheel, the sixth shifting element K2 which is a freewheel, and the seventh shifting element K3 which is a freewheel are not locking.

FIG. 18 shows one embodiment of the bottom bracket gear mechanism according to the invention on the basis of the first embodiment, in the case of which a torque sensor 5 is connected or connectable to the pedal crank shaft or to the gear mechanism input shaft WAn. For example, a disk-shaped torque sensor 5 is arranged on the gear mechanism input. The torque sensor 5 can also be configured in a different way, however.

FIGS. 19 and 20 each show one embodiment of the bottom bracket gear mechanism according to the invention on the basis of the first embodiment with an additional electric machine EM. The electric machine EM is attached to the pedal crank shaft WAn, as is indicated in FIG. 19. It is also conceivable that the electric machine EM is attached to the gear mechanism output shaft WAb, as is shown in FIG. 20. The electric machine EM is preferably arranged axially parallel to the pedal crank shaft or gear mechanism input shaft Wan. A coaxial arrangement of the electric machine EM with respect to the pedal crank shaft would also be possible, however. Regardless of this, it is advantageous for the electric machine EM to be attached via a freewheel F0 or the like, in order that no losses are caused by the corotating electric machine EM in the case of operation without the electric machine EM.

FIG. 21 shows one embodiment of the bottom bracket gear mechanism according to the invention on the basis of the first embodiment with an additional freewheel F1 between the pedal crank shaft and the gear mechanism input shaft WAn. In this way, in the case of pedaling interruption, the freewheel opens and decouples the pedal crank shaft from the inertial masses of the gear mechanism gear set and, in particular, the electric machine EM, with the result that no mass forces are perceptible at the pedal.

Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

LIST OF DESIGNATIONS

- 1 Bicycle or pedelec
- 2 Housing or bottom bracket housing
- 3 Multi-step main gear mechanism
- 4 Gear mechanism shifting group
- 5 Torque sensor
- EM Electric machine
- F0 Freewheel for electric machine
- F1 Additional freewheel
- SR1 Sun gear of the first planetary gear set
- PT1 Planetary gear carrier of the first planetary gear set
- HR1 Ring gear of the first planetary gear set
- SR2 Sun gear of the second planetary gear set
- PT2 Planetary gear carrier of the second planetary gear set
- HR2 Ring gear of the second planetary gear set
- SR3 Sun gear of the third planetary gear set
- PT3 Planetary gear carrier of the third planetary gear set
- HR3 Ring gear of the third planetary gear set
- SR4 Sun gear of the fourth planetary gear set
- PT4 Planetary gear carrier of the fourth planetary gear set
- HR4 Ring gear of the fourth planetary gear set
- SRA First sun gear in the case of a plus multi-step gear set
- SRB Second sun gear in the case of a plus multi-step gear set
- HRA First ring gear in the case of a plus multi-step gear set
- HRB Second ring gear in the case of a plus multi-step gear set
- RS1 First planetary gear set
- RS2 Second planetary gear set
- RS3 Third planetary gear set
- RS4 Fourth planetary gear set
- WAn Pedal crank shaft
- WAb Gear mechanism output shaft
- W1 First shaft
- W2 Second shaft
- W3 Third shaft
- W4 Fourth shaft
- W5 Fifth shaft
- W6 Sixth shaft
- W7 Seventh shaft
- W8 Eighth shaft
- V1 First gear in the gear mechanism shifting group
- V2 Second gear in the gear mechanism shifting group
- V3 Third gear in the gear mechanism shifting group
- G1 First gear of the bottom bracket gear mechanism
- G2 Second gear of the bottom bracket gear mechanism
- G3 Third gear of the bottom bracket gear mechanism
- G4 Fourth gear of the bottom bracket gear mechanism
- G5 Fifth gear of the bottom bracket gear mechanism
- G6 Sixth gear of the bottom bracket gear mechanism
- G7 Seventh gear of the bottom bracket gear mechanism
- G8 Eighth gear of the bottom bracket gear mechanism
- G9 Ninth gear of the bottom bracket gear mechanism
- G10 Tenth gear of the bottom bracket gear mechanism
- G11 Eleventh gear of the bottom bracket gear mechanism
- G12 Twelfth gear of the bottom bracket gear mechanism
- B1 First shifting element which is a brake
- B2 Second shifting element which is a brake
- B3 Third shifting element which is a brake
- B4 Fourth shifting element which is a brake
- K1^I, K1^II, K1^III, K1^IV, K1^V, K1^VIFifth shifting element which is a clutch or freewheel
- K2 Sixth shifting element which is a clutch or freewheel
- K3 Seventh shifting element which is a clutch or freewheel
- 1-SR First element as sun gear
- 2-PT Second element as planetary gear carrier
- 2-HR Second element as ring gear
- 3-HR Third element as ring gear
- 3-PT Third element as planetary gear carrier
- 1-SRA First element as first sun gear
- 2-SRB Second element as second sun gear
- 1-HRA First element as first ring gear
- 2-HRB First element as second ring gear