WO1997027099A1

WO1997027099A1 - Bicycle chain drive with a derailleur

Info

Publication number: WO1997027099A1
Application number: PCT/EP1997/000272
Authority: WO
Inventors: Robert Schmitt
Original assignee: Robert Schmitt
Priority date: 1996-01-25
Filing date: 1997-01-21
Publication date: 1997-07-31

Abstract

The invention concerns a bicycle chain drive or the like with a derailleur, comprising a first sprocket arrangement (2), disposed on a tread crank axle, and a second sprocket assembly (4), disposed on a wheel axle. The sprocket assemblies (2, 4) can be drivingly interconnected by means of a driving chain (6). At least one of the sprocket assemblies comprises several sprockets with which an adjustable chain-guide element is associated for throwing the driving chain over from one sprocket to the other. In order to compensate a lateral deflection of the chain in extreme change-over conditions and so reduce wear on the chain and sprockets, at least one (2) of the sprocket assemblies (2, 4) is disposed so as to be displaceable in the direction of its sprocket axis and is connected to actuating means so that it can be moved into different operating positions and locked in these positions. The actuating means for the displaceable sprocket assembly (2) are preferably formed by a hydraulic actuator to which the rider can apply pressure medium and control.

Description

Bicycle chain drive with a derailleur system

The present invention relates to a bicycle chain drive or the like with a derailleur system, comprising a first sprocket arrangement arranged on a pedal crankshaft and a second sprocket arrangement arranged on a wheel axle, which can be connected to one another via a drive chain, at least one of the sprocket arrangements is designed as a multiple sprocket and is associated with an adjustable chain guide element for throwing the drive chain from one sprocket to another.

At this point, it should be expressly pointed out that the term "chain drive" also includes equivalent drives, for example belt drives, the term "chain", for example, using "flat belts", "V-belts" or "toothed belts", the term "sprocket" would accordingly be replaced by "belt pulley". Bicycle chain drives of this type allow the drive ratio to be changed in stages and to be adapted to the respective driving conditions, for example road gradients. The different sprockets of a multiple sprocket have different diameters and numbers of teeth, so that different transmission ratios can be produced by throwing the drive chain from one sprocket to the other. Such bicycle chain drives are generally known.

A disadvantage of conventional bicycle chain drives of the type mentioned in the preamble of claim 1 is seen in the fact that the two sprockets over which the drive chain runs are in alignment with one another and the drive chain in the one with only one or with a few switching states Sprockets defined level runs. In all other circuit states, the drive chain is deflected from the plane defined by a first ring gear to another plane defined by the second ring gear. In the case of a bicycle chain drive in which, for example, the rear sprocket arrangement assigned to the wheel has seven or more sprockets, which is quite common, in extreme cases in which the largest or the smallest transmission ratio has been selected, there are very strong deflections which affect the drive ¬ adversely affect drive conditions. The deflection of the drive chain leads on the one hand to increased wear of the drive chain itself, ie in particular to a knocking out of the joints connecting the individual chain links, but on the other hand also to increased wear of the sprockets. This deflection also increases the running resistance of the drive chain and thus the resistance that the cyclist has to overcome. Another not to be neglected point is that a strongly deflected drive chain causes considerable running noise, which is also unpleasant in the long run.

It is the object of the present invention to provide a bicycle chain drive of the type mentioned in the preamble of claim 1, in which the disadvantages caused by a deflection of the drive chain can be eliminated.

This object is achieved by the features described in claim 1.

It is provided according to the invention that at least one of the sprocket assemblies is arranged so as to be adjustable in the direction of its sprocket axis and is connected to actuating means for adjusting the same in different operating positions and for locking in these operating positions. The cyclist thus has the possibility of displacing the adjustable sprocket arrangement in such a way that the sprocket over which the drive chain runs is aligned completely or at least largely in alignment with the sprocket receiving the drive chain of the other sprocket arrangement, so that a deflection of the drive chain can be avoided entirely or largely.

In order to keep the adjustment paths of the toothed ring arrangements small, it can be provided that both toothed ring arrangements are adjustable. In terms of construction and in terms of operation, however, it is simpler to make one of the two sprocket arrangements adjustable and to make the adjustment travel so large that the sprockets carrying the drive chain can be aligned with one another in all circuit positions. It is conceivable that the adjustable toothed ring arrangement can be axially adjusted together with the respectively assigned pedal crankshaft or wheel axle, the pedal crank or the wheel axle then being connected to the actuating means. Such a constructive solution is shown schematically in one embodiment.

In a preferred embodiment, however, it is provided that the adjustable toothed ring arrangement is axially displaceably mounted on the associated pedal crankshaft or wheel axle and is then connected directly to the actuating means. Such a constructive solution is described in detail using an exemplary embodiment.

Different solutions can again be found for the actuating means for adjusting a toothed crane. In a favorable solution, which is described on the basis of the detailed exemplary embodiment, it is provided that the actuating means comprise a hydraulic actuator which is controllable by the driver and is connected to a pressure medium source. By means of a hydraulic actuator, the distance between the driver-side input end and the ring gear-side output end of the actuator can be bridged in a particularly simple manner. In another embodiment of the invention, the actuating means can comprise a mechanical actuator that can be actuated by the driver, for example a Bowden cable that is used in bicycle technology. Furthermore, an electromechanical actuator known and customary in remote control technology can also be used, as need not be explained in more detail.

In conventional bicycle chain drives with a chain shift, both sprocket arrangements are generally Multiple sprockets, wherein, for example, the front sprocket arrangement assigned to the pedal crank can have three sprockets, the rear sprocket arrangement assigned to the drive wheel can have seven or more sprockets. In this case, the adjustable ring gear arrangement is a multiple ring gear. In order not to change the shift position selected for this multiple sprocket during the axial adjustment of this multiple sprocket for the purpose of compensating for a drive chain deflection, the invention provides that the chain guide element assigned to the multiple sprocket is coupled to the adjustable sprocket arrangement in such a way that it the adjustment movement of the same is always taken along.

In a bicycle chain drive in which both sprocket assemblies are designed as multiple sprockets, it is further provided according to the invention that the multiple sprockets each have the same axial sprocket spacing, that one of the two sprocket arrangements is adjustable, and that this sprocket arrangement from an initial position, in which the outer ring gear of this ring gear arrangement is aligned with the inner ring gear of the other ring gear arrangement, in the same steps corresponding to the ring gear spacing, to an end position, in which the inner ring gear of the adjustable ring gear arrangement with the outer ring gear of the other Gear arrangement is aligned, is adjustable. In this way, an adjustment position for the adjustable sprocket can be found for all circuit arrangements, in which the two sprockets carrying the drive chain and, at the same time, a certain number of further sprockets are aligned with one another.

In a preferred embodiment of the invention, the ring gear arranged on the pedal crankshaft is slidably mounted on this; According to a constructive embodiment, it is provided that a pedal crank housing is fixedly arranged on the bicycle frame, in which the pedal crankshaft is rotatably and axially immovably mounted, the sprocket arrangement being arranged on a section of the pedal crankshaft located outside the pedal crankcase in a rotationally fixed and axially displaceable manner ¬ is arranged, and that the ring gear arrangement is connected via a rotary bearing with the actuating means for the axial adjustment of this ring gear arrangement. In one embodiment of the invention, the actuating means comprise an axially adjustable hydraulic actuator, the movable actuator of which is coupled to the ring gear arrangement. This hydraulic actuator preferably has at least one actuating piston which is acted upon on two sides, which is displaceably arranged in an associated cylinder formed in the bottom bracket housing, and the piston rod which is led out of the bottom bracket housing is coupled to the ring gear arrangement. By acting on one or the other side of the actuating piston, it is adjusted in one or the other direction. Another solution provides that the actuating piston can be acted upon on one side, the resetting being carried out via spring means.

In order to rule out tilting of the ring gear arrangement on the pedal crankshaft, it is provided according to the invention that the hydraulic actuator comprises a plurality of actuating pistons which are arranged uniformly around the pedal crankshaft and which are hydraulically connected in parallel with one another. Such an arrangement is described in more detail using the detailed exemplary embodiment. According to one embodiment of the invention, the hydraulic actuator is coupled to the ring gear arrangement in such a way that the hydraulic actuator is coupled to a ring element arranged coaxially to the pedal crankshaft outside the bottom bracket shell, which in turn is axially connected to the ring gear arrangement via a ring bearing fixed but rotatably connected. In this way, the connection is established between the actuator, which is fixed in the bicycle frame with respect to the pedal crank axis, and the rotatable ring gear arrangement.

It is further provided according to the invention that the chain guide element is arranged on an arm connected to the movable adjusting element of the actuator and carried by it in the direction of the axial adjustment, this chain guide element itself relative to the arm essentially parallel to the axial adjustment by means of a gear shift lever is arranged adjustable, as will be explained in more detail with reference to the embodiment.

In order to make it clear to the driver whether and how far the drive chain is laterally deflected after a switching operation, ie by what amount and in which direction the adjustable sprocket arrangement has to be adjusted, sensors are provided according to the invention which determine the position of the drive chain can grasp on the respective multiple toothed rings; Furthermore, a display device is provided which evaluates the signals from the sensors and which shows the deviation of the adjustable sprocket arrangement both in terms of its size and in terms of its direction from a position in which the two sprockets carrying the drive chain are aligned. The driver then adjusts the adjustable sprocket Order in the specified direction until the deviation is zero.

Since the position of the drive chain on the respective multiple sprocket is also represented, for example, by the position of the assigned chain guide elements or the associated switching elements that can be actuated by the driver, the sensors can also detect the respective position of the chain guide elements or switching elements .

In a further embodiment, a control device can also be provided which generates a deviation signal from the signals from the sensors and which controls the actuating means for the adjustable ring gear arrangement in such a way that the deviation becomes zero.

The pressure medium source for a hydraulic actuator comprises, for example, a pressure medium container which is connected to the hydraulic actuator via at least one pressure line. The pressure in the pressure medium container can be generated, for example, by a pump driven by the driver himself or in any other way. The pressure line can be connected, for example, via a valve which can be controlled by the driver to one or the other side of an actuating piston which can be acted upon on two sides.

In a preferred embodiment of the invention it is provided that the pressure medium source comprises a displacement piston which can be actuated by the driver and which is displaceable in a cylinder and separates two cylinder spaces from one another in this cylinder, each of the cylinder spaces via ^" a pressure line with a cylinder chamber of the double-acting actuator piston is connected. The displacement piston can be actuated, for example, by a turning handle of the bicycle handlebar.

As described above, the adjustment of the adjustable toothed ring arrangement can be automated in such a way that it is automatically correctly aligned. However, the configuration described above with sensors and a separate control device is structurally very complex and generally does not cope with the rough operation, particularly of mountain bikes. It is therefore a further object of the present invention to provide an automatic adjustment of the adjustable ring gear arrangement which is structurally simple and robust in operation. This object is achieved according to a further embodiment of the invention in that the actuating means for the adjustable sprocket arrangement are directly coupled to the circuit means for the chain guide elements of the sprocket arrangements in such a way that each time the drive chain is shifted from one sprocket to another, the adjustable one Sprocket arrangement is adjusted by a corresponding amount in order to compensate for the lateral chain deflection. If only one sprocket arrangement is designed as a multiple sprocket, it is sufficient to adjust the adjustable sprocket arrangement in each case by an amount corresponding to the shifting path in order to compensate for the lateral deflection of the chain caused by the shifting.

For the generally present case that both toothed ring arrangements are designed as multiple toothed rings and that one of the toothed ring arrangements is adjustable, according to a further embodiment of the invention seen that the switching means of both gear ring arrangements are each coupled to the actuating means for the adjustable ring gear arrangement in such a way that the switching movements of the switching means can be transmitted to the actuating means in a manner superimposed on one another. Simple mechanical or hydraulic devices, for example, are conceivable for such a superimposed transmission of the circuit movements, as will be explained with reference to exemplary embodiments. Such an arrangement ensures that the actual net chain deflection caused by the superimposed shifting movements of both sprocket arrangements is compensated for.

In the event that the actuating means for the adjustable ring gear arrangement comprises a double-acting hydraulic actuator, as stated above as a preferred embodiment, it is provided in a further embodiment of the invention that the circuit means for the first and second ring gear assemblies are each connected to a double-acting hydraulic control cylinder, one cylinder chamber of each control cylinder being connected to one cylinder chamber of the hydraulic actuator, the other cylinder chamber of each control cylinder being connected to the other cylinder chamber of the actuator, and that being connected to the cylinder chambers of the two control cylinders connected to the same cylinder chamber of the actuator are each connected hydraulically to one another. With such an arrangement, the circuit movements for the two ring gear arrangements can be superimposed in the sense described above. The movable elements of each control cylinder, for example the piston rods, are each mechanical with a movable element the associated circuit means, for example a Bowden cable or connected to the associated chain guide element.

The control cylinders are preferably attached to a common carrier housing, in which the cylinder chambers of the control cylinders are interconnected lines and which can be connected to the cylinder chambers of the actuator via supply lines.

In order to compensate for leakage losses in the hydraulic circuits assigned to the two cylinder chambers of the hydraulic actuator, these are each connected to a reservoir for a hydraulic fluid via a connecting line and a check valve arranged therein and opening towards the hydraulic circuit. If hydraulic fluid is lost in one of the hydraulic circuits, the missing amount of hydraulic fluid is automatically drawn in via the check valve, so that the hydraulic circuits are always completely filled.

In the case of a mechanical solution for the automatic adjustment of the adjustable ring gear arrangement, the actuating means for the adjustable ring gear arrangement preferably comprise a multi-stage cam disk, or the like, associated with the circuit means for the ring gear arrangements, or the like, via which the adjustable ring gear arrangement counteracts the force of a return spring is adjusted, as will be explained using an exemplary embodiment. Several exemplary embodiments of the invention are shown in the drawing and described in more detail below. Show it:

Fig. La to le schematically different Schaltungs¬ positions for a derailleur with two multiple sprockets;

2 schematically shows an arrangement with a toothed ring fixedly arranged on a displaceable pedal crankshaft;

FIGS. 3a and 3b show an arrangement with a multiple toothed ring mounted displaceably on an axially fixed pedal crankshaft in a side sectional view and a front view;

Fig. 4 is a schematic representation of a

Pressure medium source;

5 schematically shows an arrangement for detecting the switching position of a multiple toothed ring,

6 schematically shows a hydraulic actuating device for the adjustable ring gear arrangement;

Fig. 7 is a constructive perspective

Design of the control cylinder of the actuator of Fig. 6; 8 schematically shows a mechanical actuation device for the adjustable ring gear arrangement.

1 a schematically shows a derailleur for a bicycle with a front multiple sprocket 2 assigned to the pedal crankshaft, which has three usable sprockets, and with a rear multiple sprocket 4 assigned to the drive wheel, which has eight usable sprockets. Fig. La shows the usual arrangement for this case with axially immovable Mehrfach¬ sprockets, the inner ring gear 2 near the bicycle frame of the front multiple sprocket has the smallest diameter, followed by a central sprocket 2_ with a medium diameter and an outer tooth ¬ wreath 2 .. with the largest diameter. In the rear sprocket arrangement 4, the diameter of the usable sprockets decreases in steps from the inner sprocket 4 ₁ to the outer sprocket 4 _fi , as can be seen in FIG.

In conventional arrangements of this type, both multiple sprockets 2, 4 are arranged axially fixed, in general in such a way that the central sprocket 2_ of the front sprocket arrangement 2 with a central sprocket, for example 4th , the rear sprocket assembly 4 is aligned. In this way it is achieved that the greatest possible lateral deflection of the drive chain 6 can correspond approximately to half the axial extent of the rear sprocket arrangement 4. Fig. La shows a Schaltungs¬ position in which the drive chain 6 forward over the intermediate sprocket 2 and rear ₂ runs over the alignment with this ring gear 4 and is therefore not deflected seit¬ Lich. Fig. Lb shows in the left diagram of an image Schaltungsstel¬ lung, wherein the drive chain forward, 6 runs over the sprocket mittle¬ ren 2_ far back over the outer ring gear 4 _7. Without an axial displacement of one of the two sprockets, the drive chain 6 is laterally deflected by an amount which corresponds to three times the distance (equal to a) between the rear sprockets. The disadvantages associated with such a deflection have been described above. The right schematic diagram of FIG. 1b shows the same circuit arrangement as the left schematic diagram, but the front sprocket arrangement 2 has been axially displaced outward so that its central sprocket 2_ is aligned with the rear sprocket 4_. This corresponds to an adjustment by three times the distance a between the rear sprockets. A lateral deflection of the drive chain 6 is excluded by the adjustment of the front sprocket arrangement 2 to the outside.

1c shows a circuit position in a left-hand diagram, in which the drive chain 6 runs over the middle sprocket 2 ₂ at the front and over the inner sprocket 4 at the rear. The lateral deflection of the drive chain 6 in turn corresponds to three times the distance a of the rear sprockets. The right schematic diagram of FIG. 1 c shows the state in which the front multiple ring gear 2 has been adjusted inwards by an amount, in which the middle ring gear 2 ₂ of the front multiple ring gear 2 with the inner ring gear 4 of the rear multiple ring gear 4 is aligned so that the drive chain 6 is no longer deflected laterally.

Fig. Id shows an example of the case of the smallest possible translation, in which the drive chain 6 over the front the inner ring gear 2 .. and behind the inner ring gear 4- runs. The diagram on the left shows the case in which the front multiple sprocket 2 assumes a central position, so that the drive chain 6 is laterally deflected by an amount which corresponds to twice the distance a between the rear sprockets . Id is the front multiple sprocket 2 adjusted so far inward that the inner sprocket 2nd of the front multiple sprocket is aligned with the inner sprocket 4- of the rear multiple sprocket, so that the drive chain 6 runs in one plane without lateral deflection .

Fig. Le finally shows a case in which the drive chain 6 is guided in the front over the inner ring gear 2 ₁ and in the rear over the outer ring gear. As can be seen in the diagram on the left, the drive chain 6 is laterally deflected in this case by an amount which corresponds to five times the distance a of the rear sprockets. The diagram on the right shows a state in which the front sprocket arrangement 2 is adjusted outward to its outer end position, the inner sprocket 2. being aligned with the outer sprocket 4 _{g of} the rear sprocket arrangement 4, so that the drive chain 6 again without Deflection runs in one plane.

It can be seen that, in order to avoid any lateral chain deflection, the front sprocket arrangement 2 between an inner end position, in which the outer sprocket 2nd, is flush with the inner sprocket 4- of the rear multiple sprocket, up to the position shown in FIG. le, right schematic diagram shown outer end position must be adjustable. As can be seen in FIG. 1, the distance between the front sprockets has been chosen equal to the distance between the rear sprockets. In this way, with each axial position of the front sprocket arrangement 2, its sprockets are aligned with three sprockets of the rear multiple sprocket 4, so that three switching positions are possible without axial adjustment of the front multiple sprocket, in which the drive chain 6 is not deflected.

The axial adjustment of the front multiple ring gear 2 can be carried out continuously or in fixed steps. The required axial positions of the front multiple sprocket 2 are indicated by the dashed lines and denoted at the top of the diagrams by the numbers 0 to 9, which indicate the respective position of the middle sprocket 2_. In the case of an arrangement with three front sprockets and eight rear sprockets, ten different axial positions of the front, adjustable multiple sprocket 2 result.

2 schematically shows a bottom bracket arrangement 10 in which a bottom bracket shaft 12 is rotatably supported by ball bearings 14 in a bottom bracket sleeve 16, which in turn is arranged in a bottom bracket housing 20 so as to be displaceable in the axial direction 18. A ring gear, preferably a multiple ring gear 22, is fixed on the pedal crankshaft 12 in a rotationally fixed and axially immovable manner. A mechanical actuator 24 comprises a Bowden cable 26, the sleeve 28 of which is firmly connected to the pedal crankshaft 12 and the inner cable 30 of which is supported on the bottom bracket housing 20. The Bowden cable 26 can be refined by the driver in the switching area arranged in the Mechanism actuated and the pedal crankshaft 12 with the multiple sprocket 22 arranged thereon are axially adjusted to compensate for lateral deflection of the drive chain.

3 shows a pedal crank arrangement 40, the pedal crank shaft 42 of which is rotatably supported by ball bearings 44 in a bottom bracket sleeve 46, which in turn is arranged axially fixed in a bottom bracket housing 50 mounted on the bicycle frame 48.

A multiple toothed ring 52 is displaceable in the axial direction 54, but is arranged on the pedal crankshaft 42 in a rotationally fixed manner. For this purpose, the pedal crankshaft 42 has, for example in the area in which the multiple toothed ring 52 is displaceable, a radially toothed or polygonal outer profile (not shown) to which a corresponding inner profile of the central receiving opening 56 of the multiple toothed ring 52 corresponds. As can be seen in FIG. 3, the bottom bracket sleeve 46 is received in a central receiving opening 58 of the bottom bracket housing 50, the outer ring of the right-hand ball bearing 44 in FIG. 3 being located via an axially acting spring arrangement 60, for example a telescopic spring arrangement on an end flange 62 of the Bottom bracket housing 50 is supported, and the outer ring of the left ball bearing 44 in FIG. 3 is held in the bottom bracket housing 50 by means of a retaining bushing 64.

The actuating means for adjusting the multiple toothed ring 52 comprise a hydraulic actuator which is generally designated 66 and which, in the exemplary embodiment shown, comprises three cylinders 70-, 70_, 70 .., which are arranged uniformly around the pedal crank axis 68 and are formed in the bottom bracket housing 50 (see also FIG. 3b), of which only the cylinder 70 is visible in FIG. 3a. In each of the cylinders 70 to 70, a double-acting actuating piston is slidably arranged, of which for the sake of simplicity only the piston 72 in the cylinder 70 is shown and described. The actuating piston 72 separates two cylinder chambers 74 and 76 from one another in the cylinder 70, which can optionally be pressurized with pressure medium, the other cylinder chamber then being connected to a pressure medium return. As can be seen in FIG. 3, the cylinders 70 to 70 are closed on the inside by a screw-on cover 77, for example, which contains supply channels for supplying the cylinder chambers 74, 76. A first supply channel 78, which can be connected to the pressure medium source, opens into an annular channel 80 for supplying the cylinder chamber 74, while a second supply channel 82 opens into an annular channel 84 for supplying the cylinder chamber 76. By means of a valve, not shown, the respective cylinder chambers 74 or 76 can be pressurized with pressure medium and the actuating pistons 72 can be actuated.

The piston rods 84 of the respective actuating cylinders 72 are led out of the bottom bracket housing 50 on the right in FIG. 3a and are coupled to a ring element 86 arranged coaxially to the crankshaft 68, which in turn is rotatably connected to the multiple ring gear 52 via an annular bearing 88 is. By adjusting the adjusting pistons 72, the multiple toothed ring 52 can be adjusted in the direction of the arrow 54.

An arm 90 is fixedly connected to the ring element 86, on which an adjustable chain guide element 94 is arranged in the direction of the arrow 92. The chain guide The driving element 94 can be adjusted in a manner known per se by the driver by means of a circuit device located in the grip area thereof in order to transfer the drive chain from one sprocket to the other.

When the multiple sprocket 52 is adjusted in the direction of the arrow 54 for the purpose of compensating for the lateral chain deflection, the arm 90 and thus the chain guide element 94 are always carried along, so that the arrangement of the drive chain on the multiple sprocket 52 is not changed during this adjustment movement, as is the case is shown in dashed lines in Fig. 3a.

FIG. 4 schematically shows a pressure medium source of the type that can be used, for example, for the arrangement shown in FIG. 3. It comprises a displacer piston 96 which can be actuated by the driver and which is displaceable in a cylinder 98 and in this separates two cylinder spaces 98a and 98b from one another; each of the cylinder spaces 98a and 98b is connected via a pressure medium line 100a and 100b to a cylinder chamber 74 and 76 of the actuating piston 72, which can be acted upon on both sides. The cylinder 98 and the cylinder 70 of the hydraulic actuator 66 form a closed system which is completely filled with pressure medium. By displacing the displacement piston 96, pressure medium is supplied to one cylinder chamber of the cylinder 70, while the other cylinder chamber is relieved.

Since the pressure medium is incompressible, the hydraulic actuator 66 follows the movements of the displacement piston 96 without delay. It goes without saying that the volumes and the adjustment paths of the cylinder 98 on the one hand and the cylinder 70 on the other are coordinated. The displacer piston 96 can be actuated via the piston rod 102b emerging from the cylinder 98 at the end.

It should be pointed out that in the illustrated embodiment, the cylinder 70 of the actuator 66, on the one hand, and the cylinder 98 of the pressure medium source, on the other hand, each have corresponding cylinder chambers connected to one another with or without a piston rod, so that, for example, the larger displacement path in the cylinder space for a certain displacement 98b corresponds to the larger adjustment path when the cylinder chamber 76 is acted upon and vice versa.

An alternative to the arrangement shown in FIG. 4 is, for example, a pressure medium container, which is provided by the driver e.g. is actuated via the pedal crank pump under pressure, the cylinder chambers 72 and 76 of the hydraulic actuator 66 optionally via controllable valves with a pressure line branching from the pressure medium container or with a return line can be connected, as was not shown in detail.

A further alternative for the pressure medium source provides, for example, two displacement pumps which can be actuated by the driver with successive actuation strokes, each of which is connected to a cylinder chamber of the actuator 66; by actuating a pump, the actuating piston is displaced in one direction, whereby the other pump is reset. The pumps or their actuating means can be locked in order to hydraulically clamp the actuating piston in its respective position. 5 shows a device for detecting the respective switching position of the drive chain on a multiple sprocket. A sensor 106 arranged on the bicycle frame 104 (or on the bicycle handlebar) interacts with an encoder 108 which is adjusted in accordance with the adjustment of the chain guide element 94 (see FIG. 3). 5, the transmitter 108 is fastened to the movable cable pull of a Bowden cable 110, which is used to actuate the chain guide element 94. It is understood that the transmitter could also be arranged, for example, on the chain guide element 94 itself or on a switching element connected to the Bowden cable 110, since the positions thereof are each representative of the selected switching position of the drive chain on a multiple sprocket.

The sensor 106 generates a signal corresponding to the position of the transmitter 108, which is made visible, for example, in a display device or evaluated in a control device for automatically actuating the actuating means for adjusting the multiple toothed crane.

6 schematically shows a hydraulic actuating device 120 for the adjustable sprocket arrangement 122. It is the front, triple sprocket of a conventional bicycle chain gearshift. A chain guide element 124 serves to transfer the chain from one sprocket of the sprocket arrangement 122 to the other, as is generally known and is therefore not shown in more detail.

The ring gear arrangement 122 is in the direction of the double arrow 126 on a bottom bracket shaft slidable, according to the embodiment of FIG. 3rd

The actuating means for adjusting the sprocket arrangement 122 comprise a hydraulic actuator 128 which, according to the embodiment of FIG. 3, cylinders 130, 130 and 130 arranged uniformly around the pedal crank axis. includes. In the cylinders 130 ₁ , 130-, 130, double-acting, ie double-acting actuating pistons 132, 132 _? and 132 .. are arranged, the piston rods of which are each connected to a ring element 134 which is displaceably arranged on the pedal crank axis and carries the ring gear arrangement 122. This arrangement essentially corresponds to the arrangement shown in FIG. 3 and therefore does not need to be explained again.

The piston 136 of a first double-acting control cylinder 138 is mechanically connected to an adjustable component of the circuit arrangement for one of the ring gear arrangements, for example the front ring gear arrangement 122, so that it is adjusted in the direction of the double arrow 140 during the switching process. The arrangement is such that when the chain guide element 124 is adjusted in the direction of arrow 142, ie from the smaller sprocket to the larger sprocket, the piston 136 is adjusted in the direction of arrow 144. A pressure fluid is pressed from the left piston chamber 146 via the supply line 149 into the upper piston chambers 150 ^ 150 ₂ , 150 _{3 of} the cylinders 130 ^ 130 ₂ , 130, so that the ring gear 122 is adjusted in the direction of the arrow 148. The adjustment path corresponds in each case to the lateral deflection of the chain as a result of the switching operation, so that this is compensated for. The from the piston 132., 132 ₂ , 132., displaced hydraulic fluid is pressed via the return supply line 150 into the right piston chamber 152 of the control cylinder 138.

The piston 154 of the second control cylinder 156 is mechanically connected to a movable component of the circuit arrangement for the second, in this case rear sprocket arrangement 158 and is carried in the direction of the double arrow 159 when the rear sprocket arrangement is switched. The arrangement is such that when the chain is shifted in the direction of arrow 162, ie from the smaller sprocket to the larger sprocket of the sprocket arrangement 158, the piston 154 is adjusted in the direction of the arrow 162, with pressure fluid from the right cylinder chamber 164 into the upper cylinder chambers 150 ., 150 ₂ , 150 _{3 is} pressed so that the adjustable sprocket arrangement 122 is adjusted in the direction of the arrow 148, with which the lateral chain design occurring as a result of the switching process is compensated. The pressure fluid displaced by the actuating pistons 132, 132 ₂ , 132 ₃ is pressed into the left cylinder chamber 166 via the return supply line 150.

As can be seen in FIG. 6, the left cylinder chamber 146 and the right cylinder chamber 164 are connected to one another via a connecting line 168; the right cylinder chamber 152 and the left cylinder chamber 166 are likewise connected to one another via the branch 170 of the supply line 150. This arrangement makes it possible to superimpose the movements of the pistons 136 and 154, even if they are opposite to each other. If, for example, the front sprocket arrangement 122 on the one hand and the rear sprocket arrangement 158 on the other hand in the same direction are switched, which requires an opposite adjustment of the actuating device 120, then the pressure fluid displaced by one of the pistons 136, 154 can be pressed directly into the other control cylinder via the connecting line 168 or the branch 170, so that the hydraulic actuator 128 performs no or only a net adjustment movement.

The supply lines 149 and 150 of the hydraulic actuator 120 are connected to a reservoir 197 via connecting lines 195 and 196, respectively. A check valve 198 and 199 opening towards the associated hydraulic circuit is arranged in the connecting lines 195 and 196, respectively. If a loss of hydraulic fluid occurs in one of the hydraulic circuits, for example due to leakage, the respective hydraulic circuit sucks in fluid via the opening check valve, so that the circuit always remains filled.

7 shows a structural design of the control cylinders 138 and 156. The two control cylinders 138, 156 are fastened on a carrier housing 174 arranged between them. The connecting line 168 and the region of the branch 170 with the line sections leading to the cylinders 138, 156 are formed in the carrier housing. Two connection openings 176, 178 serve to connect the supply lines 149 and 150, respectively. The carrier housing 174 is fastened to a tube 182 of the bicycle frame by means of a clamp 180. The piston rods 184 and 186 are received in sleeves 188 and 190 via spring means (not shown), and the clamping jaws formed thereon each on one of the Bowden cables 192 and 194, respectively, which are connected to the switching devices for the ring gear assemblies are connected, are clamped. The springs arranged in the sleeves 88 and 90 serve to elastically compensate for inaccuracies in the adjustment, an elongation of the Bowden cables or also different switching paths of the two switching devices.

8 schematically shows an embodiment of the invention in which the actuating means for the adjustable toothed ring arrangement are designed mechanically. The ring gear arrangements 222 and 258 essentially correspond to the ring gear arrangements of FIG. 6.

The front sprocket arrangement 222 is adjustable in the direction of the double arrow 226. A control cam 250 is connected via schematically illustrated connecting means 252 to adjustable components, for example a Bowden cable of the actuating device for the rear sprocket arrangement 258, and is adjustable in this way in the direction of the double arrow 254. In this way, corresponding to the number of eight sprockets of the rear sprocket arrangement 258, eight cam stages 256 can be aligned in succession with a cam follower 259, so that the front sprocket 222 can be adjusted to eight different positions. The front sprocket arrangement 222 is held in contact with the respectively aligned cam step 256 via spring means 260.

The control cam 250 is also connected in the direction of the double arrow 264 by means of connecting means 262 which are mechanically connected to adjustable components of the circuit device for the front sprocket arrangement 222 corresponding to the number of sprockets of the front sprocket assembly 222 (three sprockets) from the normal position shown by solid lines in two further positions 256 'and / or 256 "adjustable to compensate for the lateral chain deviation when switching the front sprocket assembly 222.

In this way, the switching movements of the switching devices for the front or rear sprocket arrangement can be superimposed on one another.

Claims

claims

1. Bicycle chain drive or the like with a chain circuit, comprising a first sprocket arrangement arranged on a pedal crankshaft and a second sprocket arrangement arranged on a wheel axle, which can be connected to one another via a drive chain, at least one of the sprocket arrangements being designed as a multiple sprocket, and wherein This is assigned a chain guide element adjustable via switching means for throwing the drive chain from one sprocket to another, characterized in that at least one (2) of the sprocket arrangements (2, 4) is arranged so as to be adjustable in the direction of its sprocket axis and is connected to actuating means for adjusting the same in different desired operating positions and for locking in these operating positions.

2. Bicycle chain drive according to claim 1, characterized in that the adjustable ring gear arrangement (22) with the associated pedal crankshaft (12) or wheel axis together axially adjustable and the pedal crankshaft (12) or wheel axis with the actuating means (26 ) connected is.

3. Bicycle chain drive according to claim 1, characterized in that the adjustable ring gear arrangement (52) on the associated pedal crank shaft (42) or wheel axle is axially displaceably mounted and is directly connected to the actuating means (72).

4. Bicycle chain drive according to one of claims 1 to 3, characterized g e k e n n z e i c h n e t that the actuating means comprise a hydraulic actuator (66) connected to a pressure medium source and controllable by the driver.

5. Bicycle chain drive according to one of claims 1 to 3, characterized in that the actuating means (26) comprise a mechanical actuator (28, 30) which can be actuated by the driver.

6. Bicycle chain drive according to one of claims 1 to

5, in which the adjustable sprocket arrangement is a multiple sprocket, characterized in that the chain guide element (94) assigned to the multiple sprocket (52) is coupled to the adjustable sprocket arrangement (52) in such a way that it is carried along during the adjustment movement of the sprocket arrangement .

7. Bicycle chain drive according to one of claims 1 to

6, in which both sprocket arrangements are designed as multiple sprockets, characterized in that the multiple sprockets (2, 4) each have the same axial sprocket spacing (a) that a first (2) of the sprocket arrangements is adjustable, and that this sprocket arrangement (2) is in the same position from an initial position in which the outer sprocket (2,) of this sprocket arrangement is aligned with the inner sprocket (4.) of the other sprocket arrangement (4), steps corresponding to the toothed ring distance (a) into an end position in which the inner ring gear (2.) of the adjustable ring gear arrangement (2) with the outer ring gear (4g) of the other ring gear arrangement (4) is aligned, adjustable.

8. Bicycle chain drive according to one of claims 1 and 3 to 7, in which a toothed ring arrangement arranged on the pedal crank shaft is slidably mounted thereon, characterized in that a pedal crankcase (50) is located on the bicycle frame (48) ) is fixedly arranged, in which the pedal crankshaft (42) is rotatably and axially non-displaceably mounted, the toothed ring arrangement (52) on a section of the pedal crankshaft (42) located outside the pedal crankcase (50) is rotationally fixed and axially displaceable, and that the ring gear arrangement (52) is connected via a rotary bearing (88) to the actuating means (72) for the axial adjustment of the ring gear arrangement (52).

9. Bicycle chain drive according to claim 8, characterized in that an axially adjustable hydraulic actuator (66) is provided in the pedal crank housing (50), the movable adjusting element (84) of which is coupled to the ring gear arrangement (52).

10. Bicycle chain drive according to claim 9, characterized in that the hydraulic actuator (66) has at least one two-sided actuated piston (72), which is formed in a bottom bracket housing (50) in the associated cylinder (70). ) is arranged displaceably, and its piston rod (84) led out of the bottom bracket housing (50) is coupled to the ring gear arrangement (52). -SO-

11. Bicycle chain drive according to claim 10, characterized in that the hydraulic actuator (66) comprises a plurality of cylinders (70. 7 ^§ o '^ ₃ ^ arranged uniformly around the pedal crankshaft (42) and associated actuating pistons, which are hydraulically parallel are switched.

12. Bicycle chain drive according to one of the claims

9 to 11, characterized in that the hydraulic actuator (66) is coupled to a ring element (86) which is arranged coaxially to the pedal crankshaft (42) outside the bottom bracket shell (50) and which is axially connected to the ring gear arrangement (52) via a ring bearing (88) fixed but rotatably connected.

13. Bicycle chain drive according to one of the claims

9 to 12, in which the adjustable toothed ring arrangement is a multiple toothed ring, characterized in that the chain guide element (94) is connected to the movable adjusting element (84) of the actuator (66), in the direction of the axial one Adjustment entrained arm (90) is arranged, wherein the chain guide element (94) relative to the arm (90) is arranged substantially parallel (92) for the axial adjustment of the multiple sprocket by means of a gear lever or the like.

14. Bicycle chain drive according to one of the claims

1 to 13, characterized in that sensors (108) for detecting the switching position a drive chain is provided on the associated multiple sprocket (52), and that a display device is provided which indicates the deviation of the adjustable sprocket arrangement (52) from a position in which the two sprockets carrying the drive chain are aligned.

15. Bicycle chain drive according to claim 14, characterized in that the sensors (108) detect the respective position of the chain guide element (94) of a multiple sprocket or the switching elements for the same.

16. Bicycle chain drive according to claim 14 or 15, characterized in that a control device is provided which generates a deviation signal from the signals from the sensors (108), and which controls the actuating means for the adjustable ring gear arrangement (52) in this way that the deviation becomes zero.

17. Bicycle chain drive according to one of the claims

4 to 16, characterized in that the pressure medium source comprises a pressure medium container which is connected to the hydraulic actuator (66) via at least one pressure line.

18. Bicycle chain drive according to claim 17 and one of claims 10 to 16, characterized in that the pressure medium source comprises a displacer piston (96) which can be actuated by the driver and which can be displaced in a cylinder (98) and two cylinder spaces therein (98a, 98b) separates from one another, each of the cylinder spaces being connected via a pressure medium line (100a, 100b) to a cylinder chamber (74, 76) of the actuating piston (72) acted upon on two sides.

19. Bicycle chain drive according to one of claims 1 to 18, characterized in that the actuating means for the adjustable sprocket assembly are coupled to the circuit means for the chain guide elements of the sprocket assemblies in such a way that with each further switching of the drive chain from one sprocket to another adjustable sprocket arrangement is adjusted by a corresponding amount in the sense of compensating the lateral chain deflection.

20. Bicycle chain drive according to claim 19, wherein both sprocket assemblies are designed as a multiple sprocket and one of the sprocket assemblies is adjustable, characterized in that the switching means of both sprocket assemblies with the actuating means for the adjustable sprocket arrangements of the switching means are superimposed on one another are transferable to the actuating means.

21. Bicycle chain drive according to claim 19 or 20, in which the actuating means for the adjustable ring gear arrangement comprise a double-acting hydraulic actuator, characterized in that the switching means for the first and the second ring gear Order are each connected to a double-acting hydraulic control cylinder, with one cylinder chamber of each control cylinder being connected to a cylinder chamber of the hydraulic actuator, the other cylinder chamber of each control cylinder being connected to the other cylinder chamber of the actuator, and that with the cylinder chambers of the two control cylinders connected to the same cylinder chamber of the actuator are each hydraulically connected to one another.

22. Bicycle chain drive according to claim 21, characterized in that the movable elements of each control cylinder are each mechanically connected to a movable element of the associated circuit means or the associated chain guide element.

23. Bicycle chain drive according to claim 21 or 22, characterized in that the control cylinders are fastened to a common carrier housing, in which the cylinder chambers of the control cylinders are interconnected lines and which can be connected via supply lines to the cylinder chambers of the actuator.

24. Bicycle chain drive according to one of claims 21 to 23, characterized in that the hydraulic circuits assigned to the two cylinder chambers of the hydraulic actuator's actuator are each connected via a connecting line and one arranged therein to the hydraulic one Circularly opening check valve are connected to a reservoir for a hydraulic fluid.

25. Bicycle chain drive according to claim 19 or 20, characterized in that the actuating means for the adjustable Zahnkranz¬ arrangement each associated with a switching means for the sprocket assemblies, mechanically connected to this multi-stage cam or the like on the adjustable sprocket assembly against the Force of a return spring is adjustable.