WO2012025876A9

WO2012025876A9 - Freewheeling clutches

Info

Publication number: WO2012025876A9
Application number: PCT/IB2011/053692
Authority: WO
Inventors: Rudi Hoebel; Reinhard Müller
Original assignee: Clean Mobile Ag
Priority date: 2010-08-23
Filing date: 2011-08-23
Publication date: 2012-04-19
Also published as: WO2012025876A3; WO2012025876A2; WO2012025782A1

Abstract

The application discloses a freewheeling clutch which com- prises an input ring, at least three clamping elements and an output ring, the clamping elements being supported rotatably around shafts that are provided on the input ring. The clamping elements are rotatable into a freewheeling position in which the clamping elements are essentially detached from a friction surface of the output ring and a friction surface of the input ring. The clamping elements are rotatable into a predetermined first clamping position, wherein the clamping elements wedge against the friction surface of the input ring and against the friction surface of the output ring. Moreover, the clamping elements are rotatable into a predetermined second clamping position, wherein the clamping elements wedge against the friction surface of the input ring and against the friction surface of the output ring. A transmission of torque from the input ring to the output ring in the first clamping position is opposite to a transmission of torque in the second clamping position.

Description

FREEWHEELING CLUTCHES

In a freewheeling clutch, force is transmitted from a power shaft to a load shaft in primarily one transmission direction only. Particularly in vehicles with pedal drive only and ancillary pedal drive, power transmission from the freewheel is generally from an inner to an outer shaft. Here freewheels with pawls are particularly common, the pawls being designed as detents or teeth. However, so-called "noiseless"

freewheels with clamping rollers or clamping bodies are also used .

An object of this application is to provide improved

freewheeling clutches such as a pawl-less freewheeling clutch and a switchable freewheeling clutch.

According to a first aspect of the application, a

freewheeling clutch is disclosed which comprises an input ring, at least three clamping elements and an output ring, the clamping elements are supported rotatably around shafts that are provided on the input ring. The input ring may be designed as an inner ring and the output ring as an outer ring. In this case, the clamping elements take a particularly simple for, but a kinematic reversal in which the input ring ring is designed as outer ring and the output ring is designed as inner ring is also possible.

The input ring may comprise a first box, and a second box between which the clamping elements are arranged. The provision of a first and a second box facilitates the assembly of the freewheeling device. For example, the clamping elements can be arranged between the first and the second box at the mounting location.

The clamping elements may be provided in pockets or openings or the input ring wherein the shaft is provided in the openings. The openings enclose the respective shafts and clamping elements.

The clamping elements are rotatable into a freewheeling position in which the clamping elements are essentially detached from a friction surface of the output ring and a friction surface of the input ring. Advantageously, the clamping elements are not in contract with the friction surface of the output ring such that there is no additional friction and the freewheeling device is not engaged accidentally.

The clamping elements are rotatable in a first direction relative to the freewheeling position into a predetermined first clamping position. In this first clamping position the clamping elements wedge against the friction surface of the input ring and against the friction surface of the output ring such that there is a friction lock between the input ring and the clamping element and between the clamping element and the output ring.

The clamping position can cause a Hertzian stress which in turn can cause a slight deformation of contact surfaces of the clamping element with the input ring and with the output ring as well as of the corresponding friction or contact surfaces of the input ring and the output ring. Also, the shafts on which the clamping elements are supported can in general be slightly deformed. Thus, the wedging of the clamping ele- merits creates a locking connection between the input ring and the output ring with a force transmission by friction.

The clamping elements are furthermore rotatable in a second direction into a predetermined second clamping position, wherein the second direction is opposite to the first direction. In the second clamping position, the clamping elements wedge against the friction surface of the input ring and against the friction surface of the output ring. A transmission of torque from the input ring to the output ring in the first clamping position is opposite to a transmission of torque from the input ring to the output ring in the second clamping position.

By providing two clamping positions according to the application, a motor can be controlled to engage the freewheeling clutch in a desired direction by applying an appropriate torque impulse in the desired direction. The input wheel may also be driven by pedal power in which case the appropriate torque impulse is determined by the driver.

According to the application, at least one clamping element may comprise a first clamping portion and a second clamping portion, the first clamping portion being located on a first side of a plane that is perpendicular to a shaft on which the clamping element is supported and the second portion being on a second side of the plane that is perpendicular to the shaft. A centre of gravity of the first clamping portion is further away from a friction surface of the clamping element than a centre of gravity of the second clamping portion.

According to the application, the second clamping portion may serve as a counterweight which moves a centre of gravity closer to the shaft. Thereby, a required torque impulse to engage the freewheeling device is increased such that the freewheeling device is not engaged accidentally. Specifically, a centre of gravity of the second clamping portion may even be on an opposite side as the centre of gravity of the first clamping portion relative to the shaft.

Furthermore, grooves may be provided in the friction surfaces of the clamping elements and an elastic ring be provided in the grooves. This provides a simple means to create a restoring force that moves the clamping elements back to the freewheeling position. The grooves are essentially shaped as arc segments .

Specifically, four clamping elements may be provided, which are arranged in regular distances along a perimeter. Thereby, a friction surface can be provided which is larger than for only three clamping elements. The symmetric distribution provides an even distribution of the loads.

For example, the elastic ring may be provided as a snap ring, a rubber ring or a coil spring.

According to a different embodiment, springs are attached at two opposite sides of at least one clamping element and to the input ring or to at least one of the boxes . The springs may be coil spring or also torsion springs, for example. The springs may be shaped so as to provide a predetermined restoring counter force.

The application also discloses a clamping element for a freewheeling device according to the first aspect of the application which comprises a first clamping portion and a second clamping portion. The second clamping portion comprising a counterweight and the clamping element furthermore comprises a borehole which extends from one lateral surface of the clamping element to an opposite lateral surface of the clamping element. A centre of mass of the first clamping portion is on the side of a friction surface of the clamping element with respect to the borehole and a centre of mass of the counterweight is further away from or even opposite to the friction surface with respect to the borehole.

A guiding groove may be provided on a side of the friction surface of the clamping element to take up an elastic ring.

The application furthermore discloses a method for control- ling a motor with a motor controller for engaging a free- wheeling clutch according to the first aspect of the applica- tion from a freewheeling position in a desired sense of rota- tion. The method comprises receiving a selection of a desired sense of rotation, for example though a driver selection via a lever or the like. A torque impulse of a first predeter- mined height and a first predetermined duration is applied to an inner ring of the freewheeling clutch in the desired sense of rotation such that clamping elements of the freewheeling clutch wedge against an inner ring and against an outer ring of the freewheeling clutch. Thereby, torque can be transmit- ted from the input ring to the output ring via the clamping elements .

The application discloses as well a method for controlling a motor with a motor controller for disengaging a freewheeling clutch according to the first aspect of the application from an engaged position. The method comprises receiving a command for disengagement of the freewheeling clutch and applying a torque impulse of a second predetermined height and a second predetermined duration to an inner ring of the freewheeling clutch in a counter direction to the current applied torque such that clamping elements are released from an inner ring and from an outer ring of the freewheeling clutch.

The height and duration of the torque impulses may be different for engagement and disengagement and they may be stored in a computer readable memory of the motor controller.

According to a second aspect of the application, a

freewheeling device is disclosed that comprises an inner ring which is mounted on a drive shaft of a vehicle and drives the freewheeling device. Provided on the outside of the inner ring is one or more rotating elements. These rotating elements may be provided as fixed wedges mounted on the drive shaft or on the inner ring, but can also be provided as movable rollers or balls contained in a cage of the inner ring. In such an arrangement, the rollers or balls can be supported on an axle .

Furthermore, the freewheeling device has an outer ring which surrounds the inner ring and a freewheel body or freewheel ring which is positioned in the space between the inner ring and the outer ring, wherein the freewheel body comprises a plurality of movable clamping parts which are preferably of identical construction and designed to move linearly against an elastic spring force when the inner ring is rotated. A spring element is provided to generate the elastic spring force. The rotating elements are able to apply a radially outward acting force on the clamping parts. The abovementioned linear movement of the clamping parts comprises a translational movement of the clamping elements away from the inner ring and towards the outer ring or towards the inner ring and away from the outer ring. According to the application, this linear movement is different from a purely rotational motion of the clamping parts around an axis that is fixed to the outer ring or to the inner ring in which only portions of the clamping elements are moved away or towards the outer ring. However, a rotational motion of the clamping parts may be superimposed to the linear motion as well.

According to a further configuration, the spring element comprises in particular a closed rotating ring which holds the clamping parts in place. The closed ring disclosed in the application can be realised in various ways. According to a first embodiment, the closed rotating ring of the spring element is designed as an elastic ring and, in addition, the clamping parts have a region for receiving the elastic ring that can be designed as a groove with a semi-circular section and is located on the outside of the clamping parts.

According to a second embodiment the closed rotating ring of the spring device is designed as a cylinder, wherein the spring device also comprises elastic plates which are provided around the circumference of the cylinder. The clamping parts are provided on the elastic plates. In this arrangement the cylinder can, in particular, be positioned on the drive shaft such that it is supported by it.

According to a further configuration, a tension of the elastic plates increases from a raised or completely released position of the freewheel body to a clamped position of the freewheel body. Also according to this further configuration, the clamping parts move from the raised to the clamped position against the spring force of the elastic plates. This raised position refers in particular to the idle position in which there is a gap between the clamping parts and the outer ring of the freewheel which prevents the clamping parts coming into contact with the outer ring.

The freewheeling device may, in particular, be of symmetrical construction wherein the number of rotating wedges

corresponds to the number of clamping parts.

According to one embodiment of the application the

freewheeling device has clamping segments on which the clamping parts are provided, wherein the clamping segments each have a flat supporting region which is supported on one of the rotating wedges when the freewheeling device is assembled.

The aforementioned radial movement of the clamping parts involves a translational movement of the clamping parts. This means in particular that, in contrast to a freewheel which comprises clamping parts positioned such that they are able to rotate, the movement of the clamping parts is not simply a rotational movement. Advantages of the configuration

disclosed in the application are the smaller space

requirement due to the translational movement of the clamping parts and the creation of a large contact surface between the clamping parts and the inner wall of the outer ring.

According to a further configuration, the clamping parts each have an essentially wedge-shaped clamping region, wherein the radially inward facing side of the clamping regions of the clamping parts are matched to the shape of the rotating edges and the radially outward facing side are matched to the shape of the inner wall of the outer ring.

The shapes of the clamping parts and the rotating wedges can in particular be matched such that the clamping parts are extended in a wedge shape in a drive direction, while the rotating wedges on the inner ring are extended in a wedge shape counter to this drive direction. In this arrangement the inside of the clamping parts matches with the rotating wedges in such a manner as to permit the rotating wedges to move along the inside of the clamping parts, wherein the rotating wedges are in contact with the inside of the clamping parts. According to a further configuration, the clamping parts are shaped such that the clamping regions are curved, resulting in crescent-shaped clamping parts.

Moreover, the shapes of the clamping parts and the inside of the outer ring can be matched such that in a clamped position the clamping parts are in contact with areas of the inside of the outer ring. Furthermore, the surfaces of the clamping parts and/or the outer rings can be roughened. In addition, teething can be provided on the outside of the clamping bodies and/or on the inner wall of the outer ring such that the clamping body is able to engage in the inner wall of the outer ring.

According to a further configuration, the rotating wedges and the inner wall of the outer ring are shaped such as to create a self-locking connection between the inner ring and the outer ring when the freewheeling device is blocked or in a clamped position. Specifically, the self-locking connection implies a friction lock between an inner surface of the outer ring and the at least one clamping element and a form fit between the inner ring or the rotating wedges on the inner ring and the clamping element.

A further embodiment discloses a dual-action freewheel with a first clamped position in a first drive direction and a second clamped position in a second, opposing drive

direction .

In this embodiment in the first blocked position of the freewheeling device the rotating wedges and the inner wall of the outer ring are shaped such as to create a self-locking connection between the inner ring, a first subset of the clamping parts and the outer ring. In this arrangement, every other clamping part advantageously engages with the outer ring. In a second blocked position a self-locking connection is created between the inner ring, a second subset of the clamping parts and the outer ring. The clamping parts engaged in the second blocked position are advantageously those raised off the outer ring in the first blocked position and vice versa. In this arrangement, the first clamped position provides drive in a first drive direction and the second clamped position provides drive in a second drive direction.

In a further configuration the outer ring is connected to an output shaft which is positioned concentrically in relation to and at least partially encompasses the drive shaft. An output means such as a sprocket or rim flange, for example, is mounted on the output shaft. In addition, the output shaft can be connected to a further drive via a further freewheel, for example. To this end the output shaft can be designed such that it is positioned around an inner ring of the further freewheel such that in the further freewheel too the inner ring is located inside an outer ring wherein the outer ring is designed as a part of the output shaft.

In a further configuration the rotating wedges comprise - in drive direction - a perpendicular section, a slanted section and a curved outer surface. The slanted section supports clamping in a clamped position. According to the application, the outer ring can also comprise a circular recess to receive an output bearing on the output side of the freewheel body. This makes optimum use of the lateral space whilst at the same time enabling the output bearing to have a larger radius .

A freewheeling device design with four moving clamping parts is particularly advantageous. This means on one hand that the clamping parts can be large enough to ensure sufficient space on the inside of the clamping parts to enable the clamping wedges to engage while on the other the clamping parts have greater freedom of movement than in an arrangement with only two clamping parts, for example, thereby preventing the clamping parts from jamming. The application also covers freewheeling devices with two, three, five or more clamping parts. According to the application, the number of moving clamping parts usefully corresponds to the number of rotating wedges .

The application furthermore discloses a gearbox which comprises a gearset and a freewheeling clutch according to the first or second aspect of the application. Gears of the gearset are connected to the input ring and/or the output ring of the freewheeling clutch. Herein, connected means a connection via transmission elements such as shafts and gear meshings or also chains/pulleys. The application also discloses a drivetrain which an electric motor, a motor controller, and the aforementioned gearbox. The electric motor is connected to an input shaft of the gearbox and the input shaft of the gearbox is connected to an input ring or, specifically, an inner ring of the freewheeling clutch. The motor controller is adapted to engage or to disengage the freewheeling clutch.

The application discloses moreover an electric bicycle with the aforementioned drivetrain, wherein an output shaft of the gearbox is connected to at least one wheel of the electric bicycle .

Moreover, the application discloses a bicycle with a

freewheeling device according to the first or the second aspect of the application, wherein the drive shaft is designed as a crankshaft on which regions are provided for receiving pedal cranks and wherein a region for receiving an output means is provided on the output shaft.

The application discloses a gear with a freewheeling device according to the application and a bicycle with a

freewheeling device according to the application, wherein the drive shaft is designed as a crankshaft on which regions are provided for receiving pedal cranks and wherein a region for receiving an output means is provided on the output shaft. For example, an output toothed wheel can be provided on the output shaft.

The drive shaft on which the freewheel according to the application is mounted can also be designed as the output shaft of a motor or, alternatively, a second drive shaft can be provided on which is mounted a freewheel according to the application .

The application further discloses an electrically operated vehicle with a freewheeling device in which the drive shaft is designed as a crankshaft on which are provided regions for receiving pedal cranks and wherein the output shaft is connected to an electric motor - where appropriate by a further freewheel.

The embodiments according to the application are described in greater detail below with reference to the attached figures.

Fig. 1 shows a freewheel unit with a freewheel according to a first embodiment,

Fig. 2 shows the freewheel illustrated in Fig. 1 in a

raised or freewheel position,

Fig. 3 shows the freewheel illustrated in Fig. 1 in a

clamped position,

Fig. 4 shows a freewheel according to a second embodiment in a raised position,

Fig. 5 shows the freewheel illustrated in Fig. 4 in a

clamped position,

Fig. 6 shows a further embodiment of a freewheel according to the application according to the application, Fig. 7 shows an embodiment of a freewheel with two clamped positions according to the application in a first clamped position,

Fig. 8 shows the embodiment illustrated in Fig. 7 in a raised position,

Fig. 9 shows the embodiment illustrated in Fig. 7 in a second clamped position,

Fig. 10 shows a further embodiment of a freewheel with two clamped positions according to the application, Fig. 11 shows a gear of an electric bicycle with two freewheels according to the application,

Fig. 12 shows a partial view of a bidirectional freewheeling clutch,

Fig. 13 shows a view of the bidirectional freewheeling

clutch,

Fig. 14 shows a clamping element of the bidirectional freewheeling clutch,

Fig. 15 shows a first cross section through a second embod- iment of a bidirectional freewheeling clutch, and

Fig. 16 shows a second cross section through the bidirectional freewheeling clutch of Fig. 15,

Fig. 17 illustrates a torque on an outer ring in a freewheeling position and in an engaged position in a first sense of rotation, and

Fig. 18 illustrates a torque on an outer ring in a freewheeling position and in an engaged position in a second sense of rotation,

Fig. 19 shows a freewheeling device according to the first aspect of the application in which the input ring is an outer ring and the output ring is an inner ring,

Fig. 20 shows a three-wheeled bicycle with freewheeling clutches according to the application.

Fig. 1 shows an exploded drawing of a freewheel unit 10 with a freewheel 11 according to the application. Seen from left to right, the freewheel unit 10 comprises a crankshaft 13, a freewheel ring 15, an output bearing 17 and an output shaft 20 on which is mounted an outer ring 19. An arrow 22

indicates the drive direction of the freewheel unit. An axis of rotation 23 is also indicated. Provided around the circumference of the crankshaft 13 is an inner ring 21. In turn provided on the inner ring 21 are four rotating wedges, two of which are shown in Fig. 1. The rotating wedges each take up a quarter of the circumference of the inner ring. Each of the rotating wedges has a curved outer surface 24 abutting a step consisting of a slanted section 25 and a perpendicular section 26. The width of the rotating wedges increases along the curved surface 24 counter to the drive direction 22.

The freewheel ring 15 comprises four clamping segments 28, 29, 30, 31 of identical construction. The bearing 17 shown in Fig. 1 is described below in its assembled state. The clamping segments 28, 29, 30, 31 each have a wedge-shaped clamping part 32 which is mounted on a flat supporting region 33, wherein the flat supporting region 33 is oriented in a plane perpendicular to the axis of rotation 23. The wedge- shaped clamping part 32 comprises an outside in the form of a segment of a body of rotation and an inside whose distance from the outside of the clamping part 32 increases in the drive direction 22 such that the clamping part 32 tapers off in a wedge shape counter to the drive direction 22. Lateral walls connect the insides and outsides of the clamping segments 28, 29, 30, 31. The lateral walls of the clamping segments 28, 29, 30, 31 are shaped such as to create a gap 34 between the clamping segments which enlarges outwards in a wedge shape .

Set into the outside of the clamping segments 28, 29, 30, 31 is a semi-circular groove 35 in which is provided an elastic ring 36. The elastic ring 36 is preferably designed as a closed annular spring. The flat supporting regions 33 of the clamping segments 28, 29, 30, 31 are limited by an inner circumference with a radius greater than the radius of the crankshaft 13.

The rotating wedges located on the crankshaft 13 sit on the flat supporting region 33 of the clamping segments 28, 29,

30, 31 of the freewheel ring 15 such that the freewheel ring 15 is held in place laterally by the rotating wedges from the side of the inner ring 21. The outer ring 19 mounted on the drive-side end of the output shaft 20 encompasses the freewheel ring radially and on the output side. Furthermore, the output shaft 20 is designed as a hollow shaft which encompasses the output side of the crankshaft. Set into the outer ring 19 is a circular recess 37 in which the output bearing 17 is located. Provided on an output-side end of the output shaft 20 is a hexagonal section 38 for mounting an output means such as a cog or toothed wheel, for example. Here the term "drive-side" refers to the side of the inner ring 21 and the term "output-side" to the side of the hexagonal section 38 or the side of the output means not shown here.

Also provided at the ends of the crankshaft 13 are square sections 39, 40 for mounting pedal cranks.

Fig. 2 shows a section through the freewheel 11 in a raised position in which there is a gap between the clamping parts 32 of the clamping segments 28, 29, 30, 31 and the outer ring 19. In Figs. 2 and 3 the plane of intersection lies

perpendicular to the shaft 23 and immediately before the freewheel ring 15 on the drive side. All four rotating wedges 42, 43, 44, 45 can be seen in the view shown in Fig. 2. If the crankshaft 13 is rotated in the drive direction 22, the rotational movement of the crankshaft 13 is transmitted via the rotating wedges 42, 43, 44, 45 to the freewheel ring 15. This creates a centrifugal force which presses the clamping segments 39, 40, 41, 42 of the freewheel ring 15 outwards against the force of the elastic ring 36 such that the gap 46 between the clamping segments 39, 40, 41, 42 and the outer ring 19 of the freewheel 11 closes and the clamping parts 32 of the clamping segments 39, 40, 41, 42 engage with the outer ring 19. At the same time the rotating wedges 42, 43, 44, 45 move further forward in relation to the freewheel ring 15 in the drive direction 22 and press the clamping segments 39, 40, 41, 42 outwards.

If the rotation speed of the crankshaft 13 is greater than the rotation speed of the output shaft, the rotating wedges move further forward in the drive direction until a clamped position as shown in Fig. 3 is achieved. In the clamped position the centrifugal force presses the outside of the clamping segments 29, 30, 31, 32 against an inside of the outer ring 19. This creates a friction connection between the outsides of the clamping segments 29, 30, 31, 32 and the inside of the outer ring 19. The movement of the crankshaft 13 transmits a torque from the crankshaft 13 via the rotating wedges to the freewheel ring 15. This torque is transmitted from the outside of the clamping segments 29, 30, 31, 32 via the friction connection to the outer ring 19 and the output shaft 20 connected to it. If, in contrast, the rotation speed of the crankshaft 13 is less than the rotation speed of the output shaft the rotating wedges move forward counter to the drive direction. Due to friction with the crankshaft 13 the rotation speed of the freewheel ring reduces such that the freewheel ring 15 is once again raised off the inside of the outer ring 19. If the freewheel ring is in the clamped position shown in Fig. 3, a detaching force is required to release the clamped position again. The detaching force can be applied by holding the crankshaft in place or by moving it counter to the drive direction, for example.

According to the application the friction surfaces of the clamping bodies are raised off the outer ring when

freewheeling and friction losses are thus significantly lower than with a ratchet, for example. In contrast to the clamping body-type freewheel there is no need for rotationally supported clamping bodies. This design is particularly simple and robust as well as offering low-friction and low-noise operation. When the crankshaft is moved by the pedals, friction may occur intermittently between the outer surfaces of the clamping parts and the outer ring until the clamped position is released by an increase in motor speed. This effect may be advantageous for mixed pedal-/motor-operation because it gives the driver a better feel for the motor output being exerted at a given time and thus makes the transition from pedal to motor operation more even.

According to the application the outer surfaces of the clamping bodies are positioned parallel to the circumference of the outer ring. As a result, in the clamped position a region of the outside of the clamping bodies sits on the inside of the outer ring, thereby creating a large contact surface . In applications which require a centrifugal clutch and a freewheel, a freewheel according to the application can perform the role of both devices.

Instead of the four clamping segments of identical

construction shown in Fig. 1, all the embodiments can also comprise two, three or more than four clamping segments of identical construction. In such cases a corresponding number of rotating wedges is then mounted on the inner ring. The elastic ring can be made of rubber or as a wire spring or metal strip, for example. The elastic ring is inserted into a circular receiving region which can be located on the outside of the clamping segments, on the inside of the clamping segments or in the region between them. Mounting the ring on the outside in this manner produces a particularly simple and stable design. In contrast, mounting the elastic ring further inside produces a large contact surface on the outside as there is no longer any need for a groove to receive the elastic ring on the outside.

In an alternative embodiment to Fig. 1, clamping parts are provided on either side of the flat regions and two inner rings, each bearing rotating wedges, are provided on the crankshaft. The rotating wedges then engage in the clamping segments on either side of the flat region such that the clamping segments are held from both sides. This embodiment requires more space. However, it also reduces the lateral friction losses of the freewheel body and offers good lateral guidance for the freewheel body.

The output bearing can also be provided at another point on the crankshaft . However, it is preferable to locate the output bearing inside the outer ring rather than inside the output shaft since the output bearing can then be larger. When located between the freewheel body and the outer ring, the output bearing is also held laterally such that no separate means of holding the output bearing laterally is required. However, such a holding means may also be provided in order to improve lateral stability.

Designing the output bearing as a ball or rolling bearing offers low friction losses. In a cost-effective alternative an oil lubricated slide ring can also be used as the output bearing .

The application specifies a method for constructing a freewheel unit. To this end the outer ring 19 is provided with the circular recess 37 and the output shaft 20. The outer ring 19 can be produced by means of milling or casting, for example. The output bearing 17 is inserted into the circular recess 37. The freewheel ring 15 assembled by providing the four clamping segments 28, 29, 30, 31 of identical design und inserting the elastic ring 36 into the semi-circular groove 35 in the clamping segments 28, 29, 30, 31. The assembled freewheel ring 15 is also inserted into the circular recess 37. Furthermore, the crankshaft 13 is passed through the freewheel ring 15, the output bearing 17, the outer ring 19 and the output shaft. Alternatively it is possible to first place the freewheel ring 15 and the output bearing 17 on the crankshaft 13 and then introduce the crankshaft 13 into the outer ring 19 together with the freewheel ring 15 and the output bearing 17.

Figs. 4 and 5 show a further embodiment of a pawl-less freewheel according to the application wherein Fig. 4 shows the freewheel in a raised position and Fig. 5 shows it in a clamped position. Here the hatching of the inner ring 21 is omitted in the interests of clarity and parts located behind the inner ring in the direction of viewing are indicated by means of broken lines.

Six clamping segments 50, 51, 52, 53, 54, 55 are mounted at regular intervals along a cylinder 70 positioned on the drive shaft 13. The six clamping segments 50, 51, 52, 53, 54, 55 each comprise clamping parts 32' which are mounted on elastic mounting plates 56, 57, 58, 59, 60, 61 which project radially from the drive shaft. The six clamping parts 32' each have a curved inside in which engages a rotating wedge 63, 64, 65, 66, 67, 68. The rotating wedges 63, 64, 65, 66, 67, 68 are mounted on an inner disk 21 which is provided on a drive shaft.

Moreover, the six clamping parts 32' each have a curved outside which is connected in a friction fit to an outer ring 19 in the clamped position shown in Fig. 5. The six elastic mounting plates 56, 57, 58, 59, 60, 61 are shaped such that in the clamped position they have a tension greater than the tension of the elastic mounting plates 56, 57, 58, 59, 60, 61 in the raised position shown in Fig. 4 in which the elastic mounting plates 56, 57, 58, 59, 60, 61 are raised from the inner wall of the outer ring 19.

The cylinder 70 may also be located a distance from the output shaft 13. The mounting plates may also have a curve different to that shown in Figs. 4 and 5. In particular, the mounting plates 56, 57, 58, 59, 60, 61 can also be shaped such that they are flat in the raised position and curved in the clamped position. The cylinder 70 and the clamping segments 50 - 55 are preferably made of metal. Fig. 6 shows a further embodiment of a freewheel 11' ' according to the application. This embodiment is similar to the embodiment shown in Figs. 1 to 3 and elements which are the same are not explained separately here.

In contrast to the embodiment shown in Figs. 1 to 3, rotating rollers 44', 45', 42', 43' rather than rotating wedges are provided between the inner ring 21 ' and each of the clamping parts 28, 29, 30, 31. The rotating rollers are provided in cages 71 in the inner ring 21 ' .

By moving the inner ring in the drive direction 22, the clamp bodies 32 ' are pressed outwards into the clamped position by the rotating rollers 42', 43', 44', 45' if the inner ring 21' moves faster in the drive direction 22 than the outer ring 19. Using the rotating rollers the clamped position can be released again with particular ease such that the clamping parts are raised off the inner wall of the outer ring. By shaping the inner ring 21' and the clamping segments 28 to 31 appropriately or guiding or supporting the rotating rollers it is possible to ensure that the rotating rollers 42' to 45' are held in the cages 71 in the inner ring 21' and do not fall out of the cages 71.

Figs. 7 to 9 show a further embodiment of a pawl-less freewheel 11' ' ' according to the application. The following describes those features which are different from the first embodiment in Figs. 1 to 3.

As in the first embodiment, four clamping segments 28', 29', 30', 31' are provided which are held together by an elastic ring 36. According to the embodiment shown in Fig. 7 the clamping parts 32 of clamping segments 29' and 31', which are

positioned opposite one another in relation to axis of rotation 23, are shaped such that they taper in a wedge shape counter to a first drive direction 22. In contrast, the clamping parts 32 of clamping segments 28' und 30', which are positioned opposite one another in relation to axis of rotation 32, are shaped such that they taper in a wedge shape counter to a second drive direction 22', wherein the second drive direction 22 ' runs counter to the first drive direction 22.

Furthermore, four rotating wedges 42', 43', 44', 45' are provided on the inner ring 21. The rotating wedges 43' and 44', which are positioned opposite one another in relation to axis of rotation 23, are designed such that their width increases counter to the first drive direction 22. In contrast, the rotating wedges 42' and 45', which are

positioned opposite one another in relation to axis of rotation 23, are designed such that their width increases counter to the second drive direction 22' .

The embodiment illustrated in Figs. 7 to 9 provides a freewheel which works in two opposing drive directions. A freewheel of this type which works in two drive directions is particularly advantageous for small vehicles which have both a pedal drive and a motor and which also have a reverse gear. Such small vehicles generally have three or more wheels and may, for example, be used for transporting loads, as taxis or also for elderly and disabled people. Fig. 7 shows the freewheel 11 ' ' ' in a raised position in which the clamping bodies 32 are raised off the outer ring 19. This is particularly the case when the pedals are stationary or when the rotation of the crankshaft 13 falls below a minimum speed.

Fig. 8 shows a first clamped position of the freewheel 11' ' ' which is achieved when the rotation of the crankshaft 13 in the first drive direction 22 exceeds a minimum speed and the crankshaft 13 turns more quickly in the second drive

direction 22 than the outer ring 19. In the first clamped position the clamping parts 32 of opposing clamping segments 29' and 31' engage with the outer ring 19. Moreover, the clamping part 32 of clamping segment 29' is engaged with rotating wedge 45' and the clamping part 32 of the opposing clamping segment 31' is engaged with opposing rotating wedge 43'. In contrast, the clamping parts 32 of the opposing clamping segments 30' and 28' are raised off the outer ring 19.

Fig. 9 shows a second clamped position of the freewheel 11' ' ' which is achieved when the rotation of the crankshaft 13 in the second drive direction 22 ' falls below a minimum speed and the crankshaft 13 rotates more quickly in the second drive direction 22' than the outer ring 19. In the second clamped position the clamping parts 32 of opposing clamping segments 28' and 30' are engaged with the outer ring 19.

Moreover, the clamping part 32 of clamping segment 28 ' is engaged with rotating wedge 42' and clamping part 32 of opposing clamping segment 30' is engaged with opposing rotating wedge 44' . In contrast, the clamping parts 32 of opposing clamping segments 29' and 31' are raised off the outer ring 19. As is shown in Figs. 8 and 9 the outsides of the clamping parts 32 are shaped such that they sit essentially on the outer ring 19 in a clamped position. Furthermore, the outsides of the clamping parts 32 are shaped such that in a clamped position of the freewheel 11' ' ' there is a gap 73 on the side opposite the drive direction 22, 22'. This means that the clamped position can be released more easily.

The dual-action freewheel according to Figs. 7 to 9 is particularly cost-effective and space-saving and eliminates the need to fit a costly switchable freewheel. In the embodiment according to Fig. 6, too, the clamping parts are shaped such that they taper in a wedge shape alternately in first drive direction 22 and in an opposite, second drive direction 23.

According to a further embodiment, a dual-action freewheel can also be designed such that a first row of clamping parts and a first row of rotating wedges are provided in a first plane and a second row of clamping parts and a second row of rotating wedges are provided in a second plane such that the first row of clamping parts tapers in a wedge shape counter to the first drive direction 22 and the second row of clamping parts tapers in a wedge shape counter to the second drive direction 22'. In such an arrangement, pairs of oppositely shaped clamping parts can be positioned on a common clamping segment or on separate clamping segments.

An arrangement with two rows of clamping segments and two rows of rotating wedges is more costly than the embodiment shown in Figs. 7 to 9 and requires more lateral space. It ha the advantage, however, of having twice as many clamping parts engaged with the outer ring 19 in each clamped

position .

The two-row arrangement is also particularly suited to the provision of a dual-action freewheel based on the embodiment shown in Figs . 4 and 5. According to the embodiment shown in Figs. 4 and 5, the clamping segments 50 to 55 must move counter to the drive direction to switch from the raised position to the clamped position. In case of opposite drive directions it would therefore be necessary to provide additional play between the clamping segments if clamping segments in opposite directions are provided in the same plane . Nevertheless, it is also possible, based on the embodiment shown in Figs. 4 and 5, to provide a dual-action freewheel in which the clamping segments lie in the same plane. A

freewheel 11' ' ' ' of this type is shown in Fig. 10. The freewheel 11' ' ' ' is shown in the clamped position in the second drive direction 22'. As shown in Fig. 10, two rotating wedges 61, 63; 64, 65; 66, 67 designed in different

directions can be made from one part. Similarly, the rotating wedges can also be made as part of the inner ring 21 and the inner ring 21 can be made as part of the crankshaft.

Fig. 11 shows a drive unit 75 of a bicycle with a gear 78 in which are mounted two freewheels 76, 77 according to the application. The drive unit 75 comprises a housing 91 from which extends a crankshaft 79 on which are provided regions for receiving pedal cranks 80, 81. Furthermore, the gear comprises an electric motor 82 which is connected to an output shaft 83, wherein the output shaft 83 of the electric motor 82 is supported on a ball bearing 84. For reasons of clarity Fig. 11 shows no further ball or roller bearings.

Provided on the output shaft 83 of the motor is a first freewheel 76 according to the application. An outer ring 85 of the first freewheel 76 is designed as a component of a hollow shaft 86 which is positioned concentrically about the output shaft 83 of the motor 82. Provided on the hollow shaft 86 is an output toothed wheel 87. The output toothed wheel 87 engages in a second toothed wheel 88 provided on a second hollow shaft 89. The second hollow shaft 89 is positioned concentrically around the crankshaft 79. The second freewheel 77 according to the application is positioned on the

crankshaft 79. An outer ring 90 of the second freewheel 77 is shaped as a component of the second hollow shaft 89. The second hollow shaft 89 extends from the housing 91.

Positioned outside the housings 91 is a third toothed wheel 92 for transmitting a drive torque to a drive chain

positioned on the second hollow shaft 79 which is not shown here.

The gear 78 is preferably designed as a reduction gear in which the first toothed wheel 87 has fewer teeth than the second toothed wheel 88. In further configurations of the gear, for example, it is possible to provide a chain for the transmission of torque between the toothed wheels and/or for the gear to have several reduction stages. As indicated schematically in Fig. 11, the output toothed wheel 92 is connected via an output means such as chain with a drive sprocket of a drive wheel of a vehicle. Further aspects of a freewheeling device according to the second aspect of the application are provided in the item list below.

Freewheeling device with the following features:

an inner ring wherein one or more rotating elements are provided on the inner ring,

an outer ring which surrounds the inner ring, a freewheel body which is located in the space between the inner ring and the outer ring, wherein the freewheel body comprises a plurality of movable clamping parts which are designed to move radially outwards against an elastic spring force when the inner ring is rotated, wherein a spring element is provided to generate the elastic spring force, wherein the rotating elements are able to apply a radially outward acting force on the clamping parts.

Freewheeling device according to item 1, wherein the radial movement of the clamping parts involves a translational movement of the clamping parts.

Freewheeling device according to one of items 1 to 2 , wherein the clamping parts each have an essentially wedge-shaped clamping region, wherein the radially inward facing side of the clamping regions matches with the shape of the rotating wedges and the radially outward facing side of the clamping regions matches with the shape of the inner wall of the outer ring.

Freewheeling device according to item 3, wherein the clamping regions are crescent-shaped. Freewheeling device according to one of items 1 to 4 , wherein the clamping regions, the rotating wedges and the inner wall of the outer ring are shaped such that when the freewheeling device is blocked a self-locking connection is created between the inner ring and the outer ring.

Freewheeling device according to one of items 1 to 5, wherein the clamped regions, the rotating wedges and the inner wall of the outer ring are shaped such that in a first blocked position of the freewheeling device a self-locking connection is created between the inner ring, a first subset of the clamping parts and the outer ring,

and that in a second blocked position a self-locking connection is created between the inner ring, a second subset of the clamping parts and the outer ring, wherein second subset of clamping parts is different from the first subset of clamping parts.

Freewheeling device according to one of items 1 to 6, wherein the spring element has a closed rotating ring.

Freewheeling device according to item 7, wherein the closed rotating ring of the spring element is designed as an elastic ring and wherein the clamping parts have a region for receiving the elastic ring.

Freewheeling device according to item 8, wherein the receiving region for the elastic ring is designed as a groove with a semi-circular section which is located on the outside of the clamping parts. Freewheeling device according to one of items 8. to 9., wherein the freewheeling device has clamping segments on which the clamping parts are provided, wherein a flat supporting region of each of the clamping segments sits on one of the rotating wedges.

Freewheeling device according to item 7., wherein the closed rotating ring of the spring device is designed as a cylinder, wherein the spring device also has elastic plates which are provided on the circumference of the cylinder and wherein the clamping parts are provided on the elastic plates.

Freewheeling device according to item 11., wherein a tension of the elastic plates increases from a raised position of the freewheel body to a clamped position of the freewheel body.

Freewheeling device according to one of items 1 to 12, wherein the outer ring is connected to an output shaft of a vehicle and said output shaft is positioned concentrically in relation to a drive shaft of the vehicle and encompasses the drive shaft of the vehicle at least partially.

Freewheeling device according to one of items 1. to 13., wherein there are four movable clamping parts .

Freewheeling device according to one of items 1 to 13, wherein there are two, three, five or more movable clamping parts. Freewheeling device according to one of items 1. to 15., wherein the number of movable clamping parts corresponds to the number of rotating wedges.

Gear with a freewheeling device according to one of items 1. to 16.

Bicycle with a freewheeling device according to one of items 1 to 16, wherein the drive shaft is designed as a crankshaft on which regions are provided for receiving pedal cranks and wherein a region for receiving an output means is provided on the output shaft.

Bicycle with a freewheeling device according to one of items 1 to 16, wherein the drive shaft is designed as an output shaft and wherein an output toothed wheel is provided on the output shaft.

Electrically operated vehicle with a freewheeling device according to one of items 1 to 16, wherein the drive shaft is designed as a crankshaft on which are provided regions for receiving pedal cranks and wherein the output shaft is connected to an electric motor. Figure 12 shows a freewheel arrangement 111 according to the first aspect of the application. The freewheeling arrangement 111 comprises a bidirectional freewheeling clutch 110 which is shown partially in Fig. 12. Furthermore, the freewheeling arrangement comprises a solid shaft 113 and a hollow shaft 112, which is supported on the solid shaft 113. A first inner box 114 and a second inner box 115 of the freewheeling clutch 110 are arranged concentrically around the hollow shaft 112. Four identically designed clamping elements 116, 117, 118, 119 are provided between the first inner box 114 and the second inner box 115. Each of the clamping elements 116, 117, 118, 119 is rotatable around a corresponding axis which can be best seen in Fig. 14. An elastic band 120 is provided in grooves 121, which are located in the other surfaces of the clamping elements 116, 117, 118, 119. Four openings 122 are provided in the first inner box 114 and four openings 123 are provided in the second inner box. The four clamping elements 116, 117, 118, 119 are provided in corresponding openings 122, 123. The openings 122, 123 are formed such that the clamping elements 116, 117, 118, 119 are rotatable around their respective axes by a predetermined maximum angle.

The inner boxes 114, 115 define an inner ring of the freewheeling clutch 110. Bearings provide a predetermined distance between the inner boxes 114, 115 and an outer ring 125. Those bearings are not shown. The bearings may be realized as ball bearings or roller bearings, for example. The bearings can be provided between the inner boxes 114, 115 and the outer ring 125 or on the outside of the outer ring 125. While a bearing placement between the inner boxes 114, 115 and the outer ring 125 allows to fix the distance between the inner boxes 114, 115 and the outer ring more easily, a bearing placement on the outside of the outer ring 125 avoids a remaining friction of the bearings when the outer ring 125 is not driven.

Fig. 13 shows a second view of the freewheeling arrangement 111. In the view of Fig. 13, an outer ring 125 of the bidi- rectional freewheeling clutch 110 is shown. The outer ring is provided around the inner boxes 114, 115 and the clamping elements 116, 117, 118, 119 such that, in a freewheeling position, a small gap is left between the clamping elements 116, 117, 118, 119 and an inner surface of the outer ring 125. Furthermore, a second hollow shaft 126 is shown, which is also supported on the solid shaft 113. For reasons of clarity, an outer casing of the bidirectional freewheeling clutch 112 is not shown in Figs. 12 and 13.

Fig. 14 shows a clamping element 116. The clamping element 116 comprises a first clamping portion 128 and a second clamping portion. The first clamping portion 128 comprises a friction foot portion 130 and a support portion 131. The second clamping portion comprises a friction foot portion 132 and a counterweight portion 133. A bore hole 134 that is provided in the clamping element 116 extends through the clamping element 116 from a surface of the support portion 131 to a surface of the counterweight portion 133 which is opposite the surface of the support portion 131. A shaft through the borehole 134, which is not shown in Fig. 14, supports the clamping element 116. A centre of mass of the support portion 128 lies essentially on an axis 135 through the bore hole 134 while a centre of a mass of the counterweight portion 133 lies essentially opposite to a side of the friction foot portion 132 with respect to the axis 135. According to the application, the counter- weight portion 133 is provided for moving the centre of mass of the clamping element 116 closer to the axis 135. Thereby, a required torque impulse to trigger an engagement of the freewheeling clutch 110 is increased and an accidental engagement or disengagement of the freewheeling clutch is avoided.

Figs. 15 and 16 show cross sections of a second embodiment of a bidirectional freewheeling clutch 110'. The cross sections of Fig. 15 and 16 are in parallel planes which are perpendicular to an input shaft 113' . In the embodiment of Figs. 15 and 16, springs 136 are provided, which are fixed to the inner box 114' and the respective clamping elements 116', 117', 118', 119'. Broken lines in Figs. 15 and 16 indicate the wedging positions of the clamping elements 116', 117', 118', 119' . For simplicity, in Fig. 16 the wedging position is only shown for the clamping element 119'. The inner box 114' is fixed to the input shaft 113', for example by a feather key and groove connection. By way of example, a sense of rotation of the input shaft 113' is indicated by arrows 137, a rotational motion of the clamping elements 116', 117', 118', 119' is indicated by arrows 138, a tilting motion of the clamping elements 116', 117', 118', 119' is indicated by arrows 139 and a sense of rotation of an outer ring 125' is indicated by an arrow 140.

Fig. 16 shows a second cross section of the freewheeling clutch 110', wherein a direction of view along an axis of the input shaft 113' is opposite to a direction of view of Fig. 15. The form of the openings 122 is adapted such that the counterweight portion 129 of the clamping elements 116', 117', 118', 119' can move around a shaft 141 for at least a predetermined angle. By way of example, a torque flow from the second inner box 115' through the clamping element 119' to the outer ring 125' is indicated by arrows 100.

A functioning of the freewheeling clutch 110' is now ex- plained with respect to Figs. 15 and 16. The functioning of the freewheeling clutch 110 of Figs. 12 to 14 is similar. Different from the freewheeling clutch 110', a restoring force is provided by springs 36 instead of an elastic band 120.

If it is decided that the freewheeling clutch 110' is to be engaged in a desired direction, a motor controller commands a motor to apply a torque impulse of sufficient magnitude in the desired sense of rotation to the clamping elements via the input shaft 113' and the inner box 14' and the shafts 141. The clamping elements 116', 117', 118', 119' tilt in the opposite direction of the torque impulse against the restoring force of the spring 136 until the clamping elements 116', 117', 118', 119' wedge against the inner wall of the outer ring 125' in a wedging position. In the wedging positions, the clamping elements 116', 117', 118', 119' exert a Hertzian stress against the inner wall of the outer ring 125' at a first contact area. Furthermore, the clamping elements 116', 117', 118', 119' exert a Hertzian stress against an outer wall of the second inner box 115' in a second contact area. An input torque is transmitted essentially via the second contact areas, the clamping elements and 116', 117', 118', 119' and the first contact areas such that the torque flow essentially bypasses the shafts 141. When the clamping elements 116', 117', 118', 119' are wedged against the inner wall of the outer ring 125' , a torque of the input shaft 113' is transmitted to the outer ring 125' via the clamping elements 116', 117', 118', 119'. If it is decided that the freewheeling clutch 110' is to be disengaged, the motor controller commands the motor to apply a torque impulse of sufficient magnitude in the current sense of rotation. The clamping elements 116', 117', 118', 119' are released from their wedging positions and the restoring force of the spring 136 moves the clamping elements 116', 117', 118', 119' back into freewheeling positions. In the freewheeling positions of the clamping elements 116', 117', 118', 119' there is essentially no contact between the clamping elements 116', 117', 118', 119' and the inner wall of the outer ring 125' and there is essentially no torque transfer from the input shaft 113' to the outer ring 125' of the freewheeling clutch 110' .

The output torque from the outer ring 125' is transferred to other driven elements, for example by connecting a hollow shaft to the outer ring 125' or by providing a tooth gear or a belt pulley on the outer ring 125' . A decision to engage or disengage the freewheeling clutch may be triggered by a driver action, for example by turning a handle or the like.

Figs. 17 and 18 indicate a torque on an outer ring 125, 125' in a freewheeling position and in engaged positions in a first and a second sense of rotation. The torque is indicated on a vertical axis in arbitrary units and the time is indicated on a horizontal axis in arbitrary units. The first sense of rotation is indicated by positive torque values and the second sense of rotation by negative torque values.

During a first time interval 151 of Fig. 17, the freewheeling clutch 110 or 110' is in a freewheeling position and essentially no torque is transferred to the outer ring 125 or 125' . During a second time interval 152, a torque impulse 153 is applied to the input shaft 113 or 113' in the first sense of rotation and the freewheeling clutch 110 or 110' is engaged in the first sense of rotation. During a third time interval 154, the freewheeling clutch 110 or 110' is engaged and a variable torque is transmitted to the outer ring 125 or 125' according to the output of the motor. During a fourth time interval 155, a torque impulse 156 is applied in a sense opposite to the first sense of rotation. During a fifth time interval 157, the freewheeling clutch 110 or 110' is disengaged and in the freewheeling position again and essentially no torque is transferred to the outer ring 125 or 125'.

During a first time interval 158 of Fig. 18, the freewheeling clutch 110 or 110' is in a freewheeling position and essentially no torque is transferred to the outer ring 125 or 125' . During a second time interval 159, a torque impulse 160 is applied to the input shaft 113 or 113' in the second sense of rotation and the freewheeling clutch 110 or 110' is en- gaged in the second sense of rotation. During a third time interval 161, the freewheeling clutch 110 or 110' is engaged and a variable torque is transmitted to the outer ring 125 or 125' according to the output of the motor. During a fourth time interval 162, a torque impulse 163 is applied in a sense opposite to the second sense of rotation. During a fifth time interval 164, the freewheeling clutch 110 or 110' is disengaged and in the freewheeling position again and essentially no torque is transferred to the outer ring 125 or 125'. Fig. 19 shows a further embodiment of a freewheeling clutch 110''. The freewheeling clutch 110' comprises clamping elements 116", 117", 118", 119" which have a tooth shaped cross section. An elastic ring 120' for returning the clamping elements 116", 117", 118", 119" to a freewheeling po- sition is indicated by a dashed line. Different from the embodiments of Figs. 12 to 16, the shafts 141' on which the clamping elements 116", 117", 118", 119" are rotatably fixed are connected to an outer ring 125' ' . In a first engaged position, a first extension 142 of a clamping element 116'', 117'', 118'', 119'' wedges against an inner ring 115' ' and torque is transmitted in a first sense of rotation. By way of example, a torque flow in the first sense of rotation via the clamping element 119'' is indicated by arrows 110.

In a second engaged position, a second extension 143 of a clamping element 116'', 117'', 118'', 119'' wedges against an inner ring 115' ' and torque is transmitted in a second sense of rotation.

Further embodiments and features of the second aspect of the current application are disclosed in the following item list.

Fig. 20 shows a schematic diagram of a three-wheeled electric bicycle 165 with a gearbox 166 that comprises a first freewheeling device 167 according to the first aspect of the application and a second freewheeling device 168 according to the second aspect of the application. The electric bicycle 165 comprises among others two steerable front wheels 169, 170, the gearbox 166, and a driven rear wheel 171. The gearbox comprises an electric motor 172 with a motor

controller which is connected to a first reduction stage of a three stage reduction gearset.

In Fig. 20, chains between gear wheels of the reduction gearset as well as between an output gear and a gear of the driven rear wheel 171 are indicated by arrows. The

freewheeling device 167 according to the first aspect of the application is provided between the third reduction stage and a hollow shaft 173. The freewheeling device 168 according to the second aspect of the application is provided between a crank shaft 174 and the hollow shaft 173. Pedals 175, 176 are attached to cranks of the crankshaft 174 on both sides of the three-wheeled electric bicycle 165.

According to the embodiment of Fig. 20, both freewheeling clutches 167 and 168 are designed such that an inner ring is an input ring and an outer ring is an output ring. Herein, the input source of the input rings are provided by the electric motor and by the pedal power of a bicycle rider, respectively .

Further aspects of a freewheeling device according to the first aspect of the application are provided in the following item list.

1. A freewheeling clutch comprising

an input ring, at least three clamping elements and an output ring, the clamping elements being supported ro- tatably around shafts that are provided on the input ring,

wherein the clamping elements are rotatable into a freewheeling position in which the clamping elements are essentially detached from a friction surface of the output ring and a friction surface of the input ring,

wherein the clamping elements are rotatable into a predetermined first clamping position, the clamping elements wedging against the friction surface of the input ring and against the friction surface of the output ring,

and wherein the clamping elements are rotatable into a predetermined second clamping position, the clamping elements wedging against the friction surface of the input ring and against the friction surface of the output ring in the predetermined second clamping position, wherein a transmission of torque from the input ring to the output ring in the first clamping position is opposite to a transmission of torque in the second clamping position.

Freewheeling clutch according to item 1,. wherein at least one clamping element comprises a first clamping portion and a second clamping portion, the first clamping portion being located on a first side of a shaft on which the clamping element is supported and the second portion being on a second side of, wherein a centre of gravity of the first clamping portion is further away from a friction surface of the clamping element than a centre of gravity of the second portion.

Freewheeling clutch according to one of the preceding items, wherein grooves are provided in the friction surfaces of the clamping elements and wherein an elastic ring is provided in the grooves.

Method for controlling a motor with a motor controller for engaging a freewheeling clutch according to one of the preceding items in a desired sense of rotation, the method comprising

receiving a selection of a desired sense of rotation,

applying a torque impulse of a first predetermined height and a first predetermined duration to an inner ring of the freewheeling clutch in the desired sense of rotation such that clamping elements of the freewheeling clutch wedge against an inner ring and against an outer ring of the freewheeling clutch .

Method for controlling a motor with a motor controller for disengaging a freewheeling clutch according to one of the preceding items, the method comprising

receiving a command for disengagement of the freewheeling clutch,

applying a torque impulse of a second predetermined height and a second predetermined duration to an inner ring of the freewheeling clutch in a coun- terdirection to the current applied torque such that clamping elements are released from an inner ring and from an outer ring of the freewheeling clutch .

Advantageously, a load carrier, a carrier for a current generating engine or for an electric battery may be supported on the two steered wheels 169, 170. With the freewheeling device 167 according to the first aspect of the application, the three-wheeled bicycle 165 can be driven forwards and backwards by changing the sense of revolution of the motor 172. The freewheeling device 168 may also be of a type according to the first aspect of the application such that forward and backward pedalling is possible.

Claims

GLAIRS

1. A freewheeling clutch comprising

an input ring, at least three clamping elements and an output ring, the clamping elements being supported rotatably around shafts that are provided on the input ring,

wherein the clamping elements are rotatable into a freewheeling position in which the clamping elements are essentially detached from a friction surface of the output ring and a friction surface of the input ring, wherein the clamping elements are rotatable into a predetermined first clamping position, the clamping elements wedging against the friction surface of the input ring and against the friction surface of the output ring,

2. Freewheeling clutch according to claim 1, .wherein at

least one clamping element comprises a first clamping portion and a second clamping portion, the first clamping portion being located on a first side of a shaft on which the clamping element is supported and the second portion being on a second side of, wherein a centre of gravity of the first clamping portion is further away from a friction surface of the clamping element than a centre of gravity of the second portion.

Freewheeling clutch according to claim 1, wherein grooves are provided in the friction surfaces of the clamping elements and wherein an elastic ring is provided in the grooves .

Method for controlling a motor with a motor controller for engaging a freewheeling clutch according to claim 1 in a desired sense of rotation, the method comprising receiving a selection of a desired sense of

rotation,

applying a torque impulse of a first predetermined height and a first predetermined duration to an inner ring of the freewheeling clutch in the desired sense of rotation such that clamping elements of the freewheeling clutch wedge against an inner ring and against an outer ring of the freewheeling clutch.

Method for controlling a motor with a motor controller for disengaging a freewheeling clutch according to claim 1, the method comprising

receiving a command for disengagement of the freewheeling clutch,

applying a torque impulse of a second predetermined height and a second predetermined duration to an inner ring of the freewheeling clutch in a

counterdirection to the current applied torque such that clamping elements are released from an inner ring and from an outer ring of the freewheeling clutch.

Freewheeling device with the following features: an inner ring wherein one or more rotating elements are provided on the inner ring,

an outer ring which surrounds the inner ring, a freewheel body which is located in the space between the inner ring and the outer ring, wherein the freewheel body comprises a plurality of movable clamping parts which are linearly moveable against an elastic spring force when the inner ring is rotated, wherein at least one spring element is provided to generate the elastic spring force, wherein the rotating elements are configured to apply a radially outward acting force on the clamping parts.

7. Freewheeling device according to claim 6, wherein the clamping parts have an essentially wedge-shaped clamping region, wherein the radially inward facing side of the clamping regions matches with the shape of the rotating wedges and the radially outward facing side of the clamping regions matches with the shape of the inner wall of the outer ring.

8. Freewheeling device according to claim 7, wherein the clamping regions, the rotating wedges and an inner wall of the outer ring are shaped such that when the

freewheeling device is blocked, a self-locking connection is created between the inner ring and the outer ring.

9. Freewheeling device according to claim 7, wherein the clamping regions, the rotating wedges and the inner wall of the outer ring are shaped such that in a first blocked position of the freewheeling device a self-locking connection is created between the inner ring, a first subset of the clamping parts and the outer ring, and that in a second blocked position a self-locking connection is created between the inner ring, a second subset of the clamping parts and the outer ring, wherein second subset of clamping parts is different from the first subset of clamping parts.

10. Gearbox, the gearbox comprising a gearset and a

freewheeling clutch according to one of claims 1 to 3 or according to one of claims 6 to 7, wherein gears of the gearset are connected to the input ring and/or the output ring of the freewheeling clutch.

11. Drivetrain, the drivetrain comprising an electric motor, a motor controller, and a gearbox according to claim 10, wherein the electric motor is connected to an input shaft of the gearbox and wherein the input shaft of the gearbox is connected to an input ring of the freewheeling clutch and wherein the motor controller is adapted to engage or to disengage the freewheeling clutch.

-i-9-12. Electric bicycle with a drivetrain according to claim 11, wherein an output shaft of the gearbox is connected to at least one wheel of the electric bicycle.

·ϋ·13. Bicycle with a freewheeling device according to one of the claims 1 to 3 or one of claims 6 to 7, wherein the drive shaft is designed as a crankshaft on which regions are provided for receiving pedal cranks and wherein a region for receiving an output means is provided on the output shaft.