DE102011079009A1 - Derailleur for the gear shift of a bicycle drive and appropriately equipped gearshift - Google Patents

Abstract

There are proposed measures that simplify the switching process in a bicycle circuit and allow a very fast and precise displacement of the chain during the switching process. These measures relate to a gearshift for a bicycle drive, which is equipped with at least one chainring (1) on the bottom bracket (11) and at least one pinion (2) on the rear hub (12), wherein at least one of these two gears (1, 2) is present in multiple execution and the chainrings (1) or pinion (2) are arranged side by side in size ascending or descending sequence, with a closed chain-like transmission element (3) via a chainring (1) and a pinion (2) wherein each gearshift gear is defined by a specific combination of a chainring (1) and a pinion (2), with a tensioning device for the chain-type transmission element (3) and with at least one operable front derailleur (20, 30), with the the chain-like transmission element (3) for gear change of a chainring (1) on an adjacent chainring (1) or of a pinion (2) on an adjacent rtes pinion (2) can be relocated. Such a derailleur (30) comprises means (39) for attachment to the bicycle frame (10), guide means for the chain-like transmission element (3) which are movable relative to the arrangement of the chainrings (1) and pinion (2) and actuating means. According to the guide means of the derailleur (30) by means of an adjusting spindle (36) relative to the arrangement of the chainrings (1) or pinion (2) displaceable and the adjusting spindle (36) by means of an electric motor (38) can be driven.

Description

State of the art

The invention relates to a derailleur for the gearshift of a bicycle drive and equipped with such a derailleur gearshift.

The starting point of the present invention is a derailleur with at least one chainring on the bottom bracket and at least one pinion on the rear hub, wherein at least one of these two sprockets is present in multiple versions and the chainrings and pinions are arranged side by side in ascending or descending order of magnitude. The power transmission takes place by means of a closed chain-like transmission element which is guided via a chainring on the bottom bracket and a pinion on the rear hub. Each gearshift gear is defined by a specific combination of a chainring and a pinion. Furthermore, such a derailleur comprises a tensioning device for the chain-like transmission element and at least one operable derailleur, with which the chain-like transmission element for gear change can be shifted from one chainring to an adjacent chainring or from a pinion to an adjacent pinion. An essential part of such a derailleur are guide means for the chain-like transmission element, which are movable relative to the arrangement of the chainrings or pinions. In addition, the derailleur comprises means for attachment to the bicycle frame and actuating means.

The derailleurs known from practice derailleurs are operated purely mechanically by means of Bowden cables. The front derailleur includes a chain guide which is attached to the seat tube of the bicycle frame via a spring-loaded link mechanism. By operating the Schaltbowdenzugs this chain guide is moved substantially horizontally, relative to the arrangement of the chainrings. The chain is shifted from one chainring to an adjacent chainring. The rear derailleur, together with a chain tensioning device forms the so-called derailleur derailleur. It also comprises a spring-loaded hinge mechanism, which essentially consists of a pivoting head with pivoting arms. The pivot arms are hinged to a support head which is mounted on the bicycle frame below the rear hub. Furthermore, the rear derailleur comprises a spring-loaded chain shift rocker, which is arranged pivotably about its bearing axis on the swivel head. The chain runs over two sprockets through the shift rocker and is thus guided to the individual pinions on the rear hub. The Schaltbowdenzug the rear derailleur engages the pivot arms of the hinge mechanism. During the switching process, the pulling movement of the swivel arms is transmitted as a parallel shift on the swivel head and the chain link rocker. As a result, the chain is moved parallel and lifted to an adjacent pinion. The shift rocker with the sprocket not only serves as a chain guide but also has the function of a chain tensioner. Namely, the chain rocker arm rotates as far as its bearing axis during the switching operation against the spring force of its return spring until spring force and chain tension are in equilibrium, i. cancel each other out. As a result, the free length of the chain is adapted to the respective pinion circumference.

With the help of Schaltbowdenzüge can always be transmitted only in the pulling direction force. The switching operation in the opposite direction is made possible by a system inherent counterforce, usually the restoring force of at least one return spring. Accordingly, when operating a Schaltbowdenzugs must always be worked against this counterforce. As a result, the known derailleur, especially in conjunction with a switchable electric drive, relatively sluggish and imprecise. In addition, the operating mechanism of the known derailleur with the Schaltbowdenzüge and return springs in the hinge mechanism of the derailleur is prone to contamination and maintenance.

Disclosure of the invention

With the present invention, measures are proposed that simplify the switching process and allow a very fast and precise displacement of the chain during the switching process.

According to the invention this is achieved in that the guide means of the derailleur with the aid of an adjusting spindle relative to the arrangement of the chainrings or pinions are displaced and that the adjusting spindle by means of an electric motor is driven.

The operation of the derailleur according to the invention thus does not take place manually by means of a Bowden cable but electrically by means of an electrically driven adjusting spindle. A major advantage of this mode is that the guide means and thus the chain are always moved during the switching process with a defined force, regardless of whether is switched to a higher or a lower gear. In addition, the guide means and thus the chain can move so very quickly and position very accurately on a sprocket. The electrically driven adjusting spindle allows for very fast, precise gear changes in both directions, without the driver having to apply manual force for the operation of the derailleur. The faster and more precise the gear change, the lower the wear on the chain and sprockets. Accordingly, the inventive measures also have a positive effect on the life of the chain and sprockets.

In addition, the measures according to the invention open up the possibility of electronically controlling the switching process. The controller can be designed, for example, so that the driver only has to signal whether he wants to switch to a higher gear or back so that the derailleur or derailleurs for the chainrings and / or pinion are then automatically controlled accordingly. In this case, the driver no longer has to worry about the optimum choice of chainring / pinion combination. Furthermore, the controller may provide a switching hysteresis to assist a safe and quick gear change. In this case, the end position of the guide means for a specific gear is initially deliberately run over in order to correct the position of the guide means after the gear change against the switching direction again. On the basis of driving performance and speed, a fully automatic gear selection can be realized, which is particularly interesting for electric bicycles with motor-assisted drive and electrical system.

The measures according to the invention can be applied both to the front derailleur, with which the chain-like transmission element is displaced from one chainring to an adjacent chainring, and to the rear derailleur, which serves for displacing the chain-like transmission element from one pinion to an adjacent pinion.

A preferred embodiment of a front derailleur according to the invention comprises at least one chain guide with an inner and an outer guide element. This chain guide is slidably mounted relative to the arrangement of the chainrings on a fixable on the bicycle frame axis. In addition, it is operatively connected to a driven adjusting spindle oriented parallel to this guide axis. The Kettenleitstück can be arranged above the chainrings, so that the chain-like transmission element between the guide elements of the Kettenleitstücks is guided from above over the position of the Kettenleitstücks corresponding chainring. This embodiment of a front derailleur according to the invention is modeled on the front derailleur of a conventional derailleur. However, according to the invention, the spring-loaded linkage mechanism, via which the chain guide piece is attached to the bicycle frame, and the shift bowden cable of the conventional front derailleur are replaced by a guide shaft which can be fixed to the bicycle frame and an electrically drivable adjusting spindle.

If the gearshift is equipped with an additional tensioning device for the chain or the chain-like transmission element, the rear derailleur can be easily realized analogously to the front derailleur described above. In this case, the rear derailleur comprises at least one Kettenleitstück with an inner and an outer guide element. This chain guide is slidably mounted relative to the arrangement of the pinion on an axis fixable on the bicycle frame. In addition, it is operatively connected to a driven adjusting spindle oriented parallel to this guide axis. In principle, the Kettenleitstück can be arranged below or above the pinion, so that the chain-like transmission element between the guide elements of the Kettenleitstücks is supplied to the position of the Kettenleitstücks corresponding pinion from below or from above.

In a preferred embodiment of the invention, the rear derailleur is modeled on the rear derailleur of a conventional derailleur. In this embodiment, the rear derailleur comprises at least one deflection roller as a guide means for the chain-like transmission element. The suspension of this pulley is mounted relative to the arrangement of the pinion displaceable on a fixable on the bicycle frame axis. In addition, this suspension is operatively connected to a parallel to its guide axis aligned drivable adjusting spindle. The deflection roller is arranged in this case below the pinion, so that the chain-like transmission element is supplied to the position of the deflection roller corresponding pinion from below. It should be noted that the suspension can be realized with the at least one guide roller in the form of a pivotally mounted and spring-loaded rocker arm with two sprockets, as used in the context of conventional derailleurs as a chain guide and tensioning device. In this case, no additional tensioning device is required for the chain. Only when the gearshift comprises an additional tensioning device for the chain, the guide means of the rear derailleur can be limited to a only laterally displaceable suspension for a pulley.

In all the aforementioned embodiments, the guide means for the chain-like transmission element are slidably mounted on an axle which is fixed to the bicycle frame. For mechanical stabilization of the derailleurs, it proves to be advantageous if fixed one end of this guide shaft on the bicycle frame is and the other, free end of the guide shaft is mounted on a further sprocket, which is arranged adjacent to the outermost sprocket or sprocket, is larger than the outer sprocket and does not serve as a drive wheel.

Depending on the type of derailleur used, it may be useful or even necessary to equip the gear shift according to the invention with an independent of the derailleurs tensioning device for the chain-like transmission element. In a structurally simple and reliable embodiment of the invention, such independent tensioning device comprises at least two deflection rollers, which are mounted spaced apart in a rocker. The rocker is suspended between the bottom bracket and the rear wheel so that it is rotatable against a spring force about the suspension axis and is pivotable against a spring force about its suspension point between the two pulleys. The chain-like transmission element is guided over the two pulleys by the rocker, so that aligns the rocker depending on sprocket / pinion combination of the engaged gear until the chain tension and the spring forces of the return springs of the swing arm suspension are in balance. With this clamping device, both a length adjustment of the chain to the respective chainring / pinion combination can be realized as well as a directional compensation between the chainring on the bottom bracket and the pinion on the rear hub. The directional compensation can be further improved by the fact that the rocker of the clamping device is suspended horizontally displaceable, for example by running in a horizontally oriented rail.

As already mentioned, however, the tensioning device of the gearshift according to the invention can also be integrated in the guide means of the rear derailleur, based on the derailleur of a conventional derailleur. In this case, the chain-like transmission element is fed to the respective pinion via two pulleys, which are mounted in a spring-loaded rocker. Since the spring force of the rocker counteracts the train of the chain-like transmission element, a length compensation for the transmission element is realized on the position of the rocker and maintain a certain chain tension.

The gearshift according to the invention comprises a closed chain-like transmission element. This can be a conventional bicycle chain, for example a roller sleeve chain or a bearing collar chain. However, other transmission elements can be used in the context of the gear shift according to the invention, since the electrically driven adjusting spindle not only allows a very rapid displacement of the transmission element of a sprocket on an adjacent sprocket but also a very precise supply of the transmission element to a particular sprocket. In an advantageous embodiment of the invention, a ball wire is used as a chain-like transmission element in conjunction with appropriately designed sprockets. Such a ball wire can be pushed easier than a conventional bicycle chain laterally from and on a corresponding sprocket.

In a preferred embodiment of the invention, the actuating means for the derailleur or derailleurs comprise an operating unit for gear selection and an electronic control unit downstream of the operating unit, via which the electric motor of the at least one derailleur is driven. Thus, a switching operation according to the specifications of the driver and possibly taking into account other control parameters, such as a switching hysteresis, are executed. Depending on the design of the control gear changes can also be made automatically.

In a particularly advantageous embodiment of the invention, the control electronics automatically regulates the position of the guide means of the derailleur after each gear change, with sensor information on the chain run are taken into account.

In the case of a bicycle with electric drive, the electrical components of the gear shift according to the invention can be easily powered by the battery of the electric drive with power. In view of the fact that even bicycles without electric drive can be equipped with the gear shift according to the invention, it is advantageous if the gear shift according to the invention is equipped with its own power supply. Thus, it is proposed to couple at least one generator for supplying power to the electric motor and the control electronics to an axis of rotation, in particular to the bottom bracket axis and / or to the axis of a deflection roller. Such a generator should as far as possible also feed at least one energy store in order to also enable gear changes if there is no sufficient pedaling or chain movement.

The information transfer between the control unit, the control electronics and the electric motor and possibly the means for monitoring the chain run can be done easily via cable or wirelessly by radio.

Brief description of the drawings

As discussed above, there are several ways of teaching the present invention Invention in an advantageous manner and further develop. For this purpose, reference is made on the one hand to the claims subordinate to the independent claims and on the other hand to the following description of several embodiments of the invention with reference to FIGS.

1a shows a perspective view of a front derailleur 20 a gear shift according to the invention and

1b shows the arrangement of the front derailleur 20 on the bicycle frame 10 ;

2a illustrates the operation of the rear derailleur 30 a gear shift according to the invention with reference to a perspective view and

2 B shows the arrangement of the rear derailleur 30 on the bicycle frame 10 ;

3a shows the arrangement of a chain tensioning device according to the invention 40 on the bicycle frame 10 and

3b Illustrates the operation of the chain tensioner 40 on the basis of a schematic detail view;

4a shows a chain-like transmission element 50 and 4b shows the top view on the edge regions of a corresponding sprocket; and

5 shows the block diagram of a gear shift according to the invention 60 ,

Embodiments of the invention

In conjunction with the 1 to 4 In the following, preferred embodiments of the mechanical components of a gearshift for a bicycle drive according to the invention will be described, while with reference to the block diagram of FIG 5 the components are explained that allow actuation of the mechanical components.

The gearshift in question includes three chainrings 1 at the bottom bracket shaft 11 and eight pinions 2 at the rear hub 12 , what in the 1b and 2 B is shown. If you go from the bicycle frame 10 out, so are both the chainrings 1 as well as the pinions 2 arranged in size ascending sequence next to each other. The torque transmission between bottom bracket and rear wheel takes place with the help of a bicycle chain 3 or a closed chain-like transmission element, via a chainring 1 the bottom bracket shaft 11 and a pinion 2 the rear hub 12 is guided. This may be a conventional bicycle chain, such as a roller sleeve chain or a bearing collar chain, act or a closed ball wire 50 as he is in 4a is shown. Each sprocket and sprocket combination has a specific gear ratio that defines a gearshift gear. When switching the chain 3 shifted either from one chainring to an adjacent chainring or from one pinion to an adjacent pinion or both. For this purpose, the gearshift in question includes a front derailleur 20 and a rear derailleur 30 , The derailleurs 20 and 30 are in the 1a and 2a shown in detail. To adjust the chain length to the individual sprocket and pinion combinations, a chain tensioner is used.

The in 1a illustrated front derailleurs 20 includes a chain guide 21 with an inner guide element 211 and an outer guide member 212 as a guide for the bicycle chain. At the guide elements 211 and 212 These are two sleeves, between which the chain is guided. The chain guide 21 is on a leadership axis 22 slidably mounted. Furthermore, the front derailleur includes 20 an adjusting spindle 23 parallel to the guide axis 22 arranged and rotatable on the holder 25 the guide axis 22 is stored. The chain guide 21 is with this adjusting spindle 23 operatively connected, so that the chain guide 21 by a rotational movement of the adjusting spindle 23 along the guide axis 22 is moved without its orientation with respect to the guide axis 22 to change. The adjusting spindle 23 This is done with the help of an electric motor 24 driven, the direction of rotation via the control of the electric motor 24 is given. This allows the position of the chain guide 21 on the guide axis 22 set very precisely. At one end of the bracket 25 there is a mounting clamp 26 over which the front derailleur 20 on the bicycle frame 10 is mounted, above the bottom bracket 11 ,

The arrangement of the front derailleur 20 on the seat tube of the bicycle frame 10 is in 1b shown. As already mentioned, the gearshift in question comprises three chainrings 1 Starting from the bicycle frame 10 in ascending order on the bottom bracket shaft 11 are arranged. The derailleur 20 is so above the bottom bracket 11 on the bicycle frame 10 mounted that guide axle 22 and adjusting spindle 23 are oriented substantially perpendicular to the chain running direction and obliquely upwards, wherein the guide axis 22 to each of the three chainrings 1 has about the same distance. This is also the Kettenleitstück 21 above the chainrings 1 arranged. It can relative to the arrangement of chainrings 1 be moved and equally precisely over each of the three chainrings 1 be positioned. The chain 3 is between the guide elements 211 and 212 of the chain guide 21 from above over that chainring 1 led, the position of the chain guide 21 equivalent. Accordingly, the chain 3 by moving the chain guide 21 shifted from one chainring to an adjacent chainring and can so over all chainrings 1 be guided.

At the in 2a illustrated rear derailleur 30 The guide means for the bicycle chain also take over the function of a tensioning device at the same time. Thus, the guide means here comprise two pulleys 31 . 32 in a swingarm 33 are stored. The one end of the swingarm 33 is pivotable against a spring force on a suspension 34 attached. Since here only the inventive principle of the rear derailleur 30 to be illustrated is the swingarm 33 with the pulleys 31 . 32 shown only schematically. The suspension 34 the swingarm 33 is on a leadership axis 35 slidably mounted. Parallel to the guide axis 35 is an adjusting spindle 36 arranged and rotatable on the holder 37 the guide axis 35 stored. The suspension 34 the swingarm 33 is with this adjusting spindle 36 operatively connected, so that the swingarm 33 by a rotational movement of the adjusting spindle 36 along the guide axis 35 is moved. The adjusting spindle 36 This is done with the help of an electric motor 38 driven, the direction of rotation via the control of the electric motor 38 is given. This allows the position of the rocker 33 at the guide axis 35 set very precisely. At one end of the bracket 37 there is a mounting hole 39 for mounting the rear derailleur 30 on the bicycle frame 10 ,

The arrangement of the rear derailleur 30 on the bicycle frame 10 is in 2 B shown. As already mentioned, the gear shift in question here comprises eight pinions 2 Starting from the bicycle frame 10 in ascending order on the rear hub 12 are arranged. The derailleur 30 is below the rear wheel axle 12 mounted so that guide axle 35 and adjusting spindle 36 are oriented substantially perpendicular to the chain running direction and obliquely downwards, wherein the guide axis 35 to each of the eight pinions 2 has about the same distance. This is the swingarm 33 with the pulleys 31 and 32 below the sprocket set and can be moved along the guide axis 35 with the help of the rotary spindle 36 very precisely under each of the eight pinions 2 be positioned. The chain 3 gets the sprocket pack over the pulleys 31 and 32 in the swingarm 33 fed from below, namely that pinion 2 that is directly above the swingarm 33 located. Accordingly, the chain 3 by moving the swingarm 33 shifted from one pinion to an adjacent pinion and so can over all pinions 2 be guided. The difference in size between the pinions or chainrings when changing gear is due to the spring-loaded pivotal mounting of the rocker 33 balanced. The swingarm 33 Namely always takes the position in which the restoring force of the return spring of the rocker 33 and neutralize the chain tension.

Both front derailleur described above 20 and 30 are based on the same drive principle:
The derailleurs 20 and 30 are guided on two axes, a guide axis 22 respectively. 35 and an adjusting spindle designed as a shaft 23 respectively. 36 , The adjusting spindle 23 respectively. 36 can with the help of an electric motor 24 respectively. 38 Turned left or right, causing the with the adjusting spindle 23 respectively. 36 operatively connected guide means, ie chain guide 21 or suspension 34 with swingarm 33 , along the guide axis 22 respectively. 35 be moved forwards or backwards. Thus, the position of the guide means can be adjusted very precisely. The guide axis 22 respectively. 35 and the adjusting spindle 23 respectively. 36 are firmly connected to the bicycle frame and are oriented perpendicular to the chain running direction. They extend at approximately constant distance over all the gears, ie chainrings and pinions, so that the chain can be guided by means of the guide means on all the gears. In order to protect the circuit from dirt, accordion-like rubber cuffs can be slipped between each of the ends of the guide shaft and adjusting spindle and the guide means. To stabilize the guide axis 22 respectively. 35 and the adjusting spindle 23 respectively. 36 a dummy wheel can be added to the sprockets, which is larger than the largest chainring or the largest pinion. On this dummy wheel then the loose end of the arrangement of the guide shaft and adjusting spindle can be stored.

In the case of in 2a illustrated rear derailleur 30 the tensioning device is integrated into the guide means for the chain. The chain tensioning device can also be realized independently of the derailleurs of the gearshift. This opens up the possibility to realize the rear derailleur in the same way as in connection with 1 described front derailleur 20 ,

Such an independent chain tensioning device 40 can for example - as in 3a shown - between the bottom bracket 11 and the rear hub 12 on the bicycle frame 10 to be ordered. According to 3b includes the tensioning device 40 two pulleys 41 and 42 spaced apart in a rocker 43 are stored. This swingarm 43 is on the bicycle frame 10 suspended between bottom bracket and rear wheel, with the suspension point 44 in about the middle between the two pulleys 41 and 42 located. The suspension of the swingarm 43 includes at least two return springs, which are not shown here. That's the swingarm 43 against the spring force of a first return spring around its suspension point 44 pivotable. Besides, the swingarm is 43 against the spring force of a second return spring rotatable about the suspension axis 45 stored. The bicycle chain 3 is through the swingarm 43 over the two pulleys 41 . 42 guided. During a gear change, the swingarm 43 usually pivoted against the spring force of the first return spring to adjust the chain tension or length to the sprocket and pinion size of the inlaid gear. The pivoting movement is in 3b through the arrow 46 indicated. By a rotation of the rocker 43 against the spring force of the second return spring any offset between the selected chainring and the selected pinion can be compensated. This rotation is indicated by the arrow 47 indicated. The swingarm 43 the tensioning device 40 is also still hung horizontally displaceable, what by the arrow 48 is illustrated. This lateral displacement of the rocker 43 against the spring force of a third return spring also allows a directional compensation.

As already mentioned, the realization of the derailleur according to the invention enables a very precise positioning and guidance of the bicycle chain via a selected chainring and a selected pinion during the gear change, but also between the shifting operations. With the aid of the chain tensioning device described above, not only the free length of the chain is adapted to the selected sprocket and pinion combination but also the direction of travel to compensate for the offset between the chainring and pinion. All of these measures allow the use of a ball-studded wire rope instead of a conventional bicycle chain. Such a chain-like transmission element 50 is in 4a shown. 4b shows the view of the edge area 51 a suitably shaped sprocket. The balls and the wire rope engage in correspondingly shaped recesses in the surface of the edge region 51 and thus enable a power transmission. This special design of the ball wire 50 and the sprockets facilitate the lateral displacement of the ball wire 50 from one sprocket to an adjacent sprocket.

The block diagram of 5 illustrates the interaction of the actuating means with the mechanical components 61 the front derailleur and with the mechanical components 62 the rear derailleur of a gear shift according to the invention 60 , As mechanical components 61 and 62 Here, in particular, the guide means for the bicycle chain referred to, so for example, the slidably mounted Kettenleitstück in the case of the front derailleur and the slidably suspended rocker with the pulleys in the case of the rear derailleur. Each of the two derailleurs has its own small electric motor 63 respectively. 64 as a drive. To operate the derailleur includes the gearshift 60 Furthermore, a control unit 65 that has an electronic control system 66 is downstream. The electric motors 63 and 64 the derailleurs are via the control electronics 66 controlled according to the specifications of the user.

The functionality of the control unit 65 and the performance of the control electronics 66 are coordinated. In a particularly comfortable variant, the driver can easily specify a gear, for example by means of touch buttons, swivel handles or other donors of the control unit 65 , so the control electronics 66 then automatically identifies the appropriate chainring-sprocket combination and the electric motors 63 and 64 the front and rear derailleur so controls that the necessary switching operations are performed. For a less powerful control electronics 66 It may be necessary to specify both the front front derailleur target chainring and the rear derailleur target pinion gear selection. In order to accelerate the switching process, the control electronics can also provide a switching hysteresis, ie the crossing of the target position of the guide means for the chain. In this case, the position of the guide means is corrected automatically after the gear change against the switching direction.

In the embodiment described here, the control electronics 66 also sensor information from sensors 67 . 68 , ..., which, for example, optically monitor the chain run and compare it with stored nominal values. Based on this information, the control electronics checks 66 whether there is a need for readjustment of the guide means for the chain, and can then - if necessary - automatically correct the position of the guide means.

The electrically operated derailleurs and the other actuating means can be powered by a battery, a battery or via a dynamo with power.

In an advantageous embodiment of the invention, the gear shift is energetically self-sufficient. For example, can be used to power the in the 2a , b rear derailleur shown 30 a small generator in the axis of one of the two pulleys 31 or 32 be installed to the electric motor 38 to supply electricity. To power the in the 1a , b front derailleur shown 20 For example, a small generator can be mounted on the bottom bracket so that the bottom bracket axle passes centrally through the generator and draws its energy from the bottom bracket axle. This generator can be the electric motor 24 the front derailleur and possibly also the control unit on the handlebars with power. By additional energy storage, for example in the form of capacitors, the operability of the gearshift can be ensured, even if there is no sufficient chain movement or pedaling.

The individual components of the gear shift according to the invention can be easily connected to each other via cables and connected to a power supply. The signal transmission between the control unit on the handlebar and the two derailleurs can also be done by radio communication. The required transmitter and receiver may possibly be integrated into the other electronics of the bicycle. Since the paths of such radio links are very short, it is easy to ensure safe operation. By wireless communication between the individual components of the gearshift not only the Verschaltungsaufwand but also the weight of the gear shift according to the invention can be significantly reduced.

Claims (14)

Derailleur for the gearshift of a bicycle drive, comprising at least: - a chainring ( 1 ) on the bottom bracket shaft ( 11 ) and a pinion ( 2 ) on the rear hub ( 12 ), wherein at least one of these two gears ( 1 . 2 ) is present in multiple design and the chainrings ( 1 ) or pinion ( 2 ) are arranged side by side in ascending or descending order of magnitude, - a closed chain-like transmission element ( 3 ), which via a chainring ( 1 ) and a pinion ( 2 ), wherein each gear of the gear shift by a specific combination of a chainring ( 1 ) and a pinion ( 2 ), and - a tensioning device for the chain-like transmission element ( 3 ), and wherein the derailleur ( 20 ; 30 ) at least comprises: - means ( 26 ; 39 ) for attachment to the bicycle frame ( 10 ), - relative to the arrangement of the chainrings ( 1 ) or pinion ( 2 ) movable guide means for the chain-like transmission element ( 3 ) and - actuating means; characterized in that the guide means of the derailleur ( 20 ; 30 ) by means of an adjusting spindle ( 23 ; 36 ) relative to the arrangement of the chainrings ( 1 ) or pinion ( 2 ) are displaceable and that the adjusting spindle ( 23 ; 36 ) by means of an electric motor ( 24 ; 38 ) is drivable. Front derailleur according to claim 1, for displacing the chain-like transmission element ( 3 ) of a chainring ( 1 ) on an adjacent chainring ( 1 ), characterized in that - the guide means comprise at least one chain guide ( 21 ) with an inner and an outer guide element ( 211 . 212 ), - that the chain guide ( 21 ) relative to the arrangement of the chainrings ( 1 ) displaceable on at least one of the bicycle frame ( 10 ) fixable guide axis ( 22 ) and with a parallel to this guide axis ( 22 ) aligned drivable adjusting spindle ( 23 ) is operatively connected and - that the chain guide ( 21 ) above the chainrings ( 1 ) is arrangeable, so that the chain-like transmission element ( 3 ) between the guide elements ( 211 . 212 ) of the chain guide ( 21 ) from above the position of the chain guide ( 21 ) corresponding chainring ( 1 ) to be led. Rear derailleur according to claim 1, for displacing the chain-like transmission element from one pinion to an adjacent pinion, characterized - That the guide means comprise at least one chain guide with an inner and an outer guide member, and - That the Kettenleitstück is slidably mounted relative to the arrangement of the pinion on an at least fixed to the bicycle frame axis and is operatively connected to a parallel to this guide axis aligned drivable adjusting spindle. Rear derailleur ( 30 ) according to claim 1, for displacing the chain-like transmission element ( 3 ) of a pinion ( 2 ) on an adjacent pinion ( 2 ), characterized in that - the guide means comprise at least one deflection roller ( 31 . 32 ) for the chain-like transmission element ( 3 ), - that the suspension ( 34 . 33 ) of the pulley ( 31 . 32 ) relative to the arrangement of the pinion ( 2 ) displaceable on at least one of the bicycle frame ( 10 ) fixable guide axis ( 35 ) and with a parallel to this guide axis ( 35 ) aligned drivable adjusting spindle ( 36 ) is operatively connected and - that the deflection roller ( 31 . 32 ) below the pinion ( 2 ) is arrangeable, so that the chain-like transmission element ( 3 ) the position of the pulley ( 31 . 32 ) corresponding pinion ( 2 ) is supplied from below. Rear derailleur ( 30 ) according to claim 4, characterized in that a tensioning device is integrated in the guide means, - by the guide means two pulleys ( 31 . 32 ) in a rocker ( 33 ), and - by the rocker ( 33 ) is pivotally mounted and the bearing of the rocker ( 33 ) spring loaded is, so that about the position of the rocker ( 33 ) a length compensation of the transmission element ( 3 ) is realized. Gear change for a bicycle drive, - with at least one chainring ( 1 ) on the bottom bracket shaft ( 11 ) and at least one pinion ( 2 ) on the rear hub ( 12 ), wherein at least one of these two gears ( 1 . 2 ) is present in multiple design and the chainrings ( 1 ) or pinion ( 2 ) are arranged side by side in ascending or descending order of magnitude, - with a closed chain-like transmission element ( 3 ), which via a chainring ( 1 ) and a pinion ( 2 ), wherein each gear of the gear shift by a specific combination of a chainring ( 1 ) and a pinion ( 2 ) is defined, - with a tensioning device for the chain-like transmission element ( 3 ) and - with at least one actuatable derailleur ( 20 ; 30 ); characterized by at least one derailleur according to one of claims 1 to 5. Gearshift according to claim 6, characterized in that one end of the guide shaft of the derailleur is fixed to the bicycle frame and that the free end of the guide shaft of the derailleur is mounted on a further wheel, which is arranged next to the outermost chainring or pinion, larger than that outer chainring or pinion is and does not serve as a drive wheel. Gearshift according to one of Claims 6 or 7, with a tensioning device realized independently of the derailleurs ( 40 ) for the chain-like transmission element ( 3 ), characterized in that - the tensioning device ( 40 ) at least two spaced apart in a rocker ( 43 ) mounted pulleys ( 41 . 42 ), via which the chain-like transmission element ( 3 ), and - that the rocker ( 43 ) is suspended between the bottom bracket and the rear wheel, so that they against a spring force around the suspension axis ( 45 ) is rotatable and against a spring force about its suspension point ( 44 ) between the two pulleys ( 41 . 42 ) is pivotable. Gearshift according to claim 8, characterized in that the rocker ( 43 ) of the tensioning device ( 40 ) is suspended horizontally displaceable. Gearshift according to one of claims 6 to 9, characterized in that a ball wire ( 50 ) serves as a chain-like transmission element and that the edge regions ( 51 ) of the chainrings and pinions are shaped accordingly. Gear shift ( 60 ) according to any one of claims 6 to 10, characterized in that the actuating means comprise a control unit ( 65 ) for gear selection and that the control unit ( 65 ) an electronic control system ( 66 ), via which the electric motor ( 63 ; 64 ) of the at least one derailleur is controlled. Gear shift ( 60 ) according to claim 11, characterized in that means ( 67 . 68 , ...) are provided for monitoring the chain run and that the control electronics ( 66 ) is designed to automatically adjust the position of the guide means of the derailleur on the basis of the information thus obtained. Gearshift according to one of claims 6 to 12, characterized in that for the power supply of the electric motor and the control electronics at least one generator is arranged on a rotation axis, in particular on the bottom bracket and / or on the axis of a guide roller, which also feeds at least one energy store. Gear shift according to one of claims 11 to 13, characterized in that the information transmission between the operating unit, the control electronics, possibly the means for monitoring the chain run and the electric motor is wirelessly by radio.

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