Abstract: A transmission for a bicycle includes an input shaft (1) which is rotationally fixable to a crankshaft (2), and an output shaft (3) which is rotationally fixable to an output gear. The transmission includes at least three planetary transmissions which are operatively connected to the input shaft and to the output shaft. A single one of the planetary transmissions includes a stepped planetary gear (4) with a first gear teeth section (5) having a first diameter and a second gear teeth section (6) having a second diameter.

Abstract: A number of variations may include a product that may comprise a gear set, and first, second and third mechanical mechanisms. Each mechanical mechanism may alternatively be open or closed and each may be connected to the gear set. The mechanical mechanisms may be variously open or closed providing a number of gear ratios through the gear set. A fourth mechanical mechanism or a fixed connection may be included. A mode of operation may be provided where the first, second and third mechanical mechanisms are open, and the fourth mechanical mechanism may be closed or the fixed connection may be provided.

Abstract: To simplify the hydraulic pressure supply passage to each clutch, an multistage automatic transmission comprises an input part and output part, three clutches, two brakes, and four planetary gear sets, where the first and fourth sets are of a single pinion type and the second and third of a double pinion type. The input and output parts and the planetary gear sets connect to each other and the clutches and brakes decouple components in such a way that enlargement as a whole of the transmission and the deterioration of the responsiveness of the shift control are controlled.

Abstract: A clutch assembly is disclosed that combines a positively engaging dog clutch and one way clutch. The two devices are design such that the one way clutch never interferes with the engagement or disengagement of the dog clutch. In one embodiment, the one way clutch transmits torque in particular rotational positions and the dog teeth are circumferentially placed such that they do not engage in any of these positions. In another embodiment, the dog clutch piston, to which the teeth are secured, is permitted to rotate enough to accommodate any interference between dog teeth during engagement. In either embodiment, the teeth faces that transmit torque in the same direction as the one way clutch may be angled such that torque in that direction tends to disengage the dog clutch.

Abstract: A transmission is provided having an input member, an output member, a plurality of planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. One of the plurality of torque transmitting devices is an integrated friction launch clutch. A one-way clutch is in series relationship with the launch clutch and is configured to disconnect the launch clutch from at least one of the plurality of planetary gear sets. The torque transmitting devices include clutches and brakes actuatable in combinations of two to establish at least ten forward gear ratios and one reverse gear ratio.

Abstract: A multi-ratio transmission system with parallel vertical and coaxial planet gears is provided, including: multiple planet gear sub-systems, a coupling assembly, a setting element, a setting element controller, an annular gear, a cylindrical casing, a sprocket and a central axle. The planet gear sub-systems are disposed coaxially in series along a first axis. Each of the planet gear sub-system includes a sun gear and at least one planet gear. The coupling assembly transmits the rotation between every two adjacent planet gear sub-systems. The setting element optionally engages with the sun gear. The annular gear is engaged to the planet gear and is installed onto a one-way clutch. The cylindrical casing encloses the planet gear sub-systems. The sprocket is installed onto the one-way clutch for connecting an external transmission system. The central axle enables the hollowed tube of the setting element controller to rotate around the central axle.

Abstract: A planetary gear mechanism for a bicycle, and more particularly to a planetary gear mechanism comprising a first planetary mechanism connected coaxially in series to a second planetary mechanism, which second planetary mechanism is connected coaxially in series to a third planetary mechanism, the second planetary mechanism output is a step up in speed from the first planetary mechanism output, the third planetary mechanism output is a step up in speed from the second planetary mechanism output.

Abstract: A transmission has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices include clutches and brakes. The torque transmitting devices are each selectively engageable in combinations of at least two to establish at least ten forward speed ratios and at least one reverse speed ratio.

Abstract: A transmission is provided having a stationary member, an input member, an output member, four planetary gear sets, a plurality of coupling members and five torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The five torque transmitting mechanisms are selectively engageable to interconnect one of the first, second, and third members with another of the first, second, third members, and a stationary element. The torque transmitting mechanisms are selectively engageable in combinations of at least three to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. A first of the five torque-transmitting mechanisms is a selectable one-way clutch engageable to interconnect the third member of the fourth planetary gear set with the stationary member.

Abstract: A transmission is disclosed having an input member, an output member, and first, second, third and fourth planetary gear sets each having first, second and third members. A plurality of interconnecting members continuously interconnect one of the first, second and third members of one of the planetary gear sets with one of the first, second and third members of another of the planetary gear sets. Five torque-transmitting mechanisms are selectively engageable in combinations of at least three to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. The first of the five torque-transmitting mechanisms is a selectable one-way clutch engageable to interconnect the third member of the first planetary gear set with the stationary member.

Abstract: A transmission has four planetary gear sets, four interconnecting members and six torque-transmitting mechanisms selectively engageable in different combinations of three to establish at least eight forward speed ratios. A first of the six torque-transmitting mechanisms is selectively engageable to connect the second member of the first planetary gear set to the stationary member. A second of the six torque-transmitting mechanisms is selectively engageable to connect the input member for common rotation with the second member of the third planetary gear set. At least one of the first and the second of the six torque-transmitting mechanisms is a selectable one-way clutch configured to have a first operating mode and a second operating mode, either of which modes may be selected.

Abstract: An automatic transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may be either clutches or brakes.

Abstract: A multi-speed transmission for a vehicle is provided with a selectable one-way braking clutch (SOWBC). The transmission has an input member connected for common rotation with one of the members of four planetary gear sets and an output member connected for common rotation with another of the members of the planetary gear sets. Four interconnecting members connect different members of the planetary gear sets for common rotation. A first brake is selectively engagable to ground the first member of the first planetary gear set to the stationary member. A first, a second, and a third rotating clutch are each selectively engagable to connect a different respective pair of the members of the planetary gear sets for common rotation. A selectable one-way braking clutch is configured to brake in one rotational direction and is selectively reversible to brake in an opposite rotational direction, and freewheels in some speed ratios.

Abstract: The present invention relates to a bicycle drive unit that moves forward and backward and idles upon clockwise and counterclockwise pedaling, comprising: a drive shaft having one end located in an inner bearings of an internal bearing housing integrally formed with a rotary plate and the other end fixed to a clockwise one-way clutch and the inner wheel of a counterclockwise one-way clutch by means of a sunk key; a counterclockwise one-way clutch having a central gear press-fitted on its outer wheel; a ring gear engaged with the turnabout gear; a gear flange connected to a ring gear by means of a locking screw; a bearing housing of a dual structure consisting of an outer bearing housing having outer bearings; a brace attached to the outer circumference of the outer bearing housing by means of the locking screw; a detent pin unit for curving the internal bearing housing and the rotary plate; and a bicycle backward movement control unit having a hand lever and a detent latch.

Abstract: The output rotation of an engine is transmitted to a drive member when a vehicle starts moving, and the drive member is connected to a carrier of a speed-increasing planetary gear via a start clutch. Upon engagement of the start clutch, the rotation of the drive member is accelerated by the speed-increasing planetary gear and then transmitted to an input shaft that is directly connected to a ring gear. Such rotation transmitted to the input shaft is shifted to a plurality of speeds and transmitted to an output shaft by using a plurality of friction engagement elements to selectively connect or fix elements of a single planetary gear set and a multiple planetary gear set that is connected to the output shaft.

Abstract: The present invention relates to a bicycle drive unit of multiple pedaling modes, comprising a drive shaft on one side having a counterclockwise one-way clutch and a clockwise one-way clutch coupled thereto by means of sunk keys and the drive shaft is engaged with a ring gear having an outer circumference attached to a chain sprocket; a plurality of hollow turnabout gears engaged with the central gear of the drive shaft; a drive shaft on the other side having one side rotatably inserted into an inner bearing housing that is integrally formed with the rotary plate and the other side coupled to the inner wheels of the clockwise one-way clutch and the counterclockwise one-way clutch by means of the sunk keys and a plurality of turnabout gears, a two-way turnabout gear and a hollow turnabout gear.

Abstract: A power train of a 7-speed transmission for a vehicle is provided which comprises a first, a second, and a third single-pinion planetary gear set on an input shaft. A first ring gear and a second planetary carrier, a second ring gear and a third planetary carrier, a third ring gear and a first planetary carrier are respectively fixedly connected. A first brake selectively connects a first sun gear to a transmission case, a second sun gear is fixedly connected to the input shaft to operate always as an input element, and a third brake selectively connects a third sun gear to the transmission case.

Abstract: A powertrain includes a power transmission having an input shaft continuously connected directly between an engine and a planetary gear member of a first planetary gearset. Another member of the planetary gearset is selectively grounded by a torque transmitting mechanism to establish a reaction member during the launch of a vehicle incorporating the powertrain. The reaction member is established during both the lowest forward drive ratio and the reverse drive ratio. A third member of the planetary gearset transmits the torque from the input shaft, as modified by the planetary gearset, to other planetary gearsets in down stream power flow arrangement with the first planetary gearset.

Abstract: A planet gear carrier for a bicycle hub transmission comprises a first carrier member including a first carrier member axle opening for receiving an axle therethrough. The first carrier member includes plurality of first planet gear openings disposed on a first side of the first carrier member and a plurality of second planet gear openings disposed on a second side of the first carrier member. A separate second carrier member is fastened to the first side of the first carrier member, wherein the second carrier member has a second carrier member axle opening for receiving the axle therethrough. A separate third carrier member is fastened to the second side of the first carrier member, wherein the third carrier member has a third carrier member axle opening for receiving the axle therethrough.

Abstract: A shift control apparatus for a hub transmission includes an axle defining an axle axis; a pawl support rotating member rotatably supported around the axle axis; a pawl rotatably supported to the pawl support rotating member; a biasing mechanism for biasing the pawl in a radial direction; and a pawl control rotating member for controlling a radial position of the pawl. One of the pawl support rotating member and the pawl control rotating member includes a location for coupling to a shift control mechanism, and the other one of the pawl support rotating member and the pawl control rotating member includes a location for coupling to an actuating member. A spring is provided for biasing the pawl support rotating member and the pawl control rotating member in a rotational direction relative to each other, and a stopper is provided for holding the pawl support rotating member and the pawl control rotating member in a rotational position relative to each other.

Abstract: An apparatus for changing the speed of bicycles, more particularly, an apparatus that changes the speed of bicycles using inner gears within a rear wheel hub and controls the inner gears by means of controllers mounted on a hub shaft. The apparatus includes: a driven sprocket receiving the driving force of a driving sprocket; a speed controlling portion, which includes a carrier that is fixed to one side of the driven sprocket, containing a plurality of planetary gears with ratchet-teeth formed along their inner circumferences; at least two sun gears for engaging each step of the planetary gears at their ratchet-teeth; a ring gear engaging the other side of the planetary gears; an output portion, including a hub shell transferring the driving force to the rear wheel by means of the carrier and the ring gear; a clutch means mounted between the carrier and the hub shell, and the ring gear and the hub shell, which selectively mediates the driving force; and a speed-change controlling portion.

Abstract: A shifting device for a multi-speed hub for a bicycle that, comprises a hub axle, a driver, a hub sleeve and an epicyclical transmission with an annulus, a plant carrier, planet wheels and a sun wheel, a control device for changing the gear ratios between the multi-speed hub and a remote control. The gear change is executed exclusively by the lifting out or engagement of pawls which can be controlled by means of a shift unit. The shift sleeve and bushing have projections and gaps and can slide under a respective foot of the pawl thereby enabling the pawls to be forcibly disengaged. An advantage of the invention is the ability to disengage the respective pawl even under load without the need to employ relatively large control forces by means of the remote control.

Abstract: A sun gear apparatus includes an axle, a sun gear rotatably supported around the axle, and a sun gear guide ring disposed between an inner peripheral surface of the sun gear and the axle. The sun gear guide ring minimizes or eliminates looseness in the coupling between the sun gear and the axle.

Abstract: A speed-changing control mechanism of a multistage speed-changing wheel hub has a planetary gear device comprising a gear support and a plurality of planetary gears. The planetary gears are respectively engaged with a ring gear and sun gears. The rotational power of a drive member is transmitted to the ring gear or the gear support via a sleeve. A speed ratio change is brought about by the action of the planetary gears and the sun gears. The power is finally transmitted to the wheel hub via the gear support or the ring gear. The planetary gears are driven by the power input source portion of the sleeve in conjunction with the action of another sleeve on the fastening shaft, thereby controlling two sets of one-way ratchet pawls opposite in direction to engage or disengage.

Abstract: A double use inner brake and an inner derailleur for bikes include a post frame, plural posts and plural brake plates in the inner brake. The post frame receives reverse direction power output from an inner gear of the inner derailleur and by pulling a hand brake to move the plural posts push the brake plates outward to produce braking function. Thus the inner brake is controlled by two kinds of braking modes.

Abstract: A bicycle shifting device includes a driver, a slave, a power transmission mechanism coupled between the driver and the slave for communicating rotational power from the driver to the slave through a plurality of power transmission paths, and a clutch for selecting one of the plurality of power transmission paths in the power transmission mechanism. A clutch actuating mechanism causes the clutch to select the one of the plurality of power transmission paths when the driver is at a predetermined rotational position.

Abstract: The invention relates to a multispeed gearshift mechanism for bicycles. The gearshift mechanism contains a shaft (1), which can be mounted, fixed against relative rotation, on a bicycle frame, an actuator (7), rotatably seated on the shaft (1), a shell (12), rotatably seated on the shaft (1), and a gearshift mechanism, which is provided with a first and a second planetary gear (15, 16) and is arranged in the shell (12) for making available several gear ratios between the actuator (7) and the shell (12). The planetary gears (15, 16) have at least respectively two sun wheels (19, 20, or respectively 22, 23), which are coaxial in relation to the shaft (1) and which can be selectively connected by means of a shifting device with the shaft (1).

Abstract: A multiple speed transmission for motor vehicles includes three simple planetary gearsets hydraulically actuated friction clutches and brakes for controlling operation of the gearsets and altering the torque delivery path between an input shaft and an output shaft. An overrunning brake is provided for operation in reverse drive to share the torque reaction with a friction brake. The transmission is suited to produce five, six or seven forward speed ratios and a reverse drive ratio.

Abstract: The invention relates to a multispeed gearshift mechanism for bicycles.

Abstract: A multi-speed drive hub for bicycles includes a hub axle, an epicyclical gear unit, a drive-side coupling gear, an output-side coupling gear, first and second tooth systems, and a spring-loaded shift link. The epicyclical gear unit is mounted concentrically on the hub axle and has a ring gear, a planet-gear carrier, a plurality of double planet gears mounted rotatably on the planet-gear carrier, and two sun gears meshing with the double planet gears. The ring gear meshes with the double planet gears. The first tooth system connects the drive-side coupling gear to one of the ring gear and the planet-gear carrier. The second tooth system connects the output-side coupling gear to one of the planet-gear carrier and the ring gear. The shift link is mounted coaxially on and slidable axially of the hub axle, and has a plurality of axially spaced radial lugs provided thereon. The drive-side and output-side coupling gears are connected to the shift link to be displaced therewith along the hub axle.

Abstract: A multiple speed bicycle of the coaster brake type has a single drive sprocket and a drive chain in longitudinal alignment with one another. A sun gear is keyed to the main drive axle of the bicycle and rotates with the main drive axle. The sun gear engages a drive gear mounted on a planet gear axle and a planet gear is mounted on the same planet gear axle. Driving and driven satellite gears are mounted on satellite gear axles that are pivotally mounted on a nonrotatable ring concentric with the main drive axle. The satellite gears have differing diameters and differing numbers of teeth, one for each GEAR of the bicycle, and are positioned radially outwardly of the planet gear, in circumferentially spaced relation to one another. The planet gear orbits the main drive axle in incremental degrees of angular rotation when the bicycle operator manipulates a remote control member on the handlebar of the bicycle to change from one preselected gear to another preselected gear.

Abstract: A self-contained change speed apparatus for use on a bicycle. It has fixed shaft, a hub body rotatably supported on the fixed shaft, a change speed device controlled to turn the hub body about the fixed shaft at one of a series of speeds, and a power input member adapted to provide driving power, A clutch is moved between an active position and a non-active position and adapted to transmit driving power from the power input member to the change speed device. A control mechanism changes the speed ratio of the change speed device, advances the clutch to the non-active position before changing the speed of the change speed device, and delays the movement of the clutch to the active position, for permitting driving power to be returned to the change speed device after a change of the speed ratio of the change speed device.

Abstract: The present invention relates to a speed-changing transmission hub for a bicycle comprising: a central shaft; a controlling device; a planetary gear system, which comprises a planet gear holder, holding several planet gears; a second ring gear; a first ring gear; and two sun gears. Variations of speed are realized by separately fixing the sun gears of different diameters. There is no switching of input and no reversal of the rotation of the sun gears. The sun gears only need to be controlled by a one-way clutch guided by the controlling device, which is mounted on the central shaft. Thereby the arrangement is simplified and its weight is reduced.

Abstract: A multi-speed power transmission has five forward speeds and one reverse speed. The forward speeds consist of three underdrives, a direct drive and one overdrive. These speed ratios are produced with a simple planetary gearset, a compound planetary gearset, three input clutches, a combining clutch, a one-way clutch and two brake assemblies. Each of the brake assemblies incorporates a friction brake and a one-way brake. The combining clutch is disengaged in the low forward and reverse ratios and is engaged to connect the ring gears of the compound set with the carrier of the simple set. The one-way clutch is disposed between the ring gears of both sets to transmit rotation therebetween in an active capacity in the low forward ratio and no load capacity in the reverse ratio. In the second through fifth forward speeds, the one-way clutch permits relative rotation between the ring gears. The ring gear of the simple planetary gearset is continuously connected with the output shaft.

Abstract: A gear transmission unit for an automatic transmission comprises: a single pinion type first planetary gear unit including a first sun gear, a first ring gear arranged concentrically with the first sun gear, and a first carrier retaining a pinion meshing with both the sun gear and the ring gear; a single pinion type second planetary gear unit including a second sun gear, a second ring gear arranged concentrically with the second sun gear and connected to the first carrier, and a second carrier retaining a pinion meshing with both the second sun gear and the second ring gear and connected to the first ring gear; and a double pinion type third planetary gear unit including a third sun gear connected to the first sun gear, a third ring gear arranged concentrically with the third sun gear, and a third carrier retaining both one pinion meshing with the third sun gear and another pinion meshing with the one pinion and the third ring gear. The first carrier is connected to the third ring gear.

Abstract: A transmission assembly having an input shaft, an output shaft as well as first and second planetary gear sets. The first and second planetary gear sets each have three gear members. Two of the gear members in each planetary gear set are a sun gear and a ring gear. As such, the sun and ring gears, one in each planetary gear set, are paired. The sun and ring gears in each of the first and second planetary gear sets are operatively connected in each respective planetary gear set through the third gear members, which are in the nature of a plurality of planet gears mounted on respective first and second carriers. In one of the planetary gear sets the planet gears are themselves compounded. One of the pairs of sun and ring gears is continuously connected, and the carrier in the first planetary gear set is selectively, and independently, connected to two gear members in the second planetary gear set. The carrier in the second planetary gear set is continuously connected to the output shaft means.

Abstract: A control system for a working apparatus such as a derailleur or self-contained change speed apparatus of a bicycle, operable by a pulling force and a restoring force. This control system comprises a first sleeve shiftable in one direction by the pulling force, and in the other direction by the restoring force; a second sleeve for transmitting a shift of the first sleeve to a controlled member of the change speed apparatus to control the controlled member, the first sleeve and the second sleeve being interlocked to be shiftable relative to each other; a clutch pawl switchable between a first position to transmit rotational drive of the bicycle to the second sleeve, and a second position to break drive transmission; and a clutch controller for switching the clutch pawl to the first position in response to a relative shift between the first sleeve and the second sleeve.

Abstract: On a multispeed bicycle wheel hub with a sun and planet gear mechanism having at least two multistage planet wheels, the planet wheels are each constructed of two parts, with a first planet wheel part having a rolling gearing segment forming one planet wheel stage and a clutch gearing segment having a clutch outside circumference gearing, as well as a second planet wheel part having at least one rolling gearing segment, each forming a planet wheel stage, as well as a receptacle opening for the clutch gearing segment of the first planet wheel part, which receptacle opening is equipped with a clutch inside circumference gearing which is engaged in the clutch outside circumference gearing. The second planet wheel part is formed by a sintered part, and the first planet wheel part is formed by a machined part, whereby the clutch outside circumference gearing has the same number of teeth and gear rim orientation as the clutch outside circumference gearing.

Abstract: A speed changing gear device for an automatic transmission, comprising a main gear assembly for providing a plurality of operating positions, and an auxiliary gear assembly for providing a direct drive position and a speed changing drive position. The main gear assembly includes a single-pinion type first planetary gear unit having a first sun gear, a first planetary gear, a first ring gear and a first carrier, and a single-pinion type second planetary gear unit having a second sun gear, a second planetary gear, a second ring gear and a second carrier. The auxiliary gear assembly includes a third planetary gear unit having a third sun gear, at least one third planetary gear, a third ring gear and a third carrier. The first carrier and second ring gear are fixed to each other, or selectively connected to each other by a first clutch. The first and second sun gears, and the first sun gear and second carrier are selectively connected to each other by a second and a third clutch, respectively.

Abstract: A planetary gear system has a first planetary gear set including a first ring gear, a first sun gear and a first planet carrier, and a second planetary gear set including a second ring gear, a second sun gear and a second planet carrier. The first and second carriers are integrated into a common carrier, and at least one long pinion is provided between the first and second planetary gear sets so as to form a third equivalent planetary gear set with the first and second ring gears. This gear system can provide at least six forward speeds, and one or two reverse speeds with a compact arrangement.

Abstract: A gear train for changing the rotational speed of an input shaft to transmit the resultant rotation to an output shaft consists of single pinion type first and third planetary gear sets and a double pinion type second planetary gear set. Ring gears of these three planetary gear sets are normally or selectively interconnected to each other, a carrier of the first planetary gear set is normally or selectively connected to a sun gear of the third planetary gear set, a sun gear of the first planetary gear set is normally or selectively connected to a sun gear of the second planetary gear set, and the sun gear of the second planetary gear set is normally or selectively connected to the carrier of the first planetary gear set, whereby at least five forward speeds and one reverse are permitted to be set.

Abstract: A first and a second rotary member such as outside or inside clutch member arranged as axially juxtaposed and radially expanded to rotate individually about a common axis in a transmission for a vehicle are separately torque-transmittingly connected with a first shaft member and a hollow second shaft member coaxially and telescopingly disposed around the first shaft member to be respectively in an individually torque-transmitting relationship by first external splines formed at an outer periphery of an end portion of the first shaft member axially extending out of an open end of the second shaft member being axially placed into engagement with first internal splines formed at an inner periphery of a central bore formed in the first rotary member, while second external splines formed at an outer periphery of an end portion of the second shaft member adjacent the open end thereof are axially placed into engagement with second internal splines formed at an inner periphery of a central bore formed in the second r

Abstract: A shifting arrangement of an overdrive position of a fourth gear is connected behind a shifting arrangement of a Simpson gear set of a first gear and/or a second gear. The connection transforms a conventional four-speed automatic transmission into a five-speed automatic transmission or a six-speed automatic transmission.

Abstract: A gear train for changing the rotational speed of an input shaft to transmit the resultant rotation to an output shaft consists of single pinion type first and third planetary gear sets and a double pinion type second planetary gear set. A sun gear of the first planetary gear system is normally or selectively connected to a carrier of the third planetary gear set, the carrier of the third planetary gear set is normally or selectively connected to a sun gear of the second planetary gear set, a carrier of the first planetary gear set is normally or selectively connected to a ring gear of the third planetary gear set, a ring gear of the first planetary gear set is normally or selectively connected to a ring gear of the second planetary gear set, the sun gear of the second planetary gear set is normally or selectively connected to a sun gear of the third planetary gear set, whereby at least five forward speeds and one reverse are permitted to be set.

Abstract: The invention relates to a drive hub for six speeds, with an integral back-pedal brake device (28, 31) for bicycles or the like. The gear system comprises two separate planetary gear units (5b, 6a, 7b and 16, 26, 27 respectively), each of which comprises one stage and of which a primary gear unit (5b, 6a, 7b) is incorporated in the drive member (5), while a secondary gear unit (16, 26, 27) is disposed in the hub sleeve (1). The coupling elements (2, 3, 23 29) of the drive hub are constructed in such a manner that lost motion positions are avoided both during driving and during braking. During braking the torque flow is always guided through the secondary gear unit (16, 26, 27) in the hill speed position by means of separate detents (23) which come into operation only during the backward rotation of the drive member (5), so that the back-pedal brake is operated with a stepped-up brake force.