Vehicle, in particular two-wheeled vehicle, having a belt drive and a swingarm

Abstract

The invention relates to a vehicle (10), in particular a two-wheeled vehicle, comprising a frame (12), a driven wheel (14), in particular a driven rear wheel, a propulsion system (16), in particular having an electric motor (20), and a suspension (18) by means of which the wheel (14) is resiliently connected to the frame (12), wherein: a belt drive (22) is provided which is arranged to transmit a propulsion torque from the propulsion system (16) to the wheel (14) and which has an input belt pulley (36), a belt (24), a belt tensioner (28) arranged to apply a tensioning force to a slack strand (30) of the belt (24), and an output belt pulley (26) arranged concentrically with the wheel (14); the suspension (18) has a swingarm (32) mounted in a swingarm bearing (34) on the frame (12) and having a free end to which the wheel (14) is fastened and having a swingarm spring (37) for preloading the swingarm (32) in a rest position; an input belt pulley rotational axis (D36) is spaced apart from a swingarm instantaneous pivot axis (S32) about which the swingarm (32) pivots.

Description

[0001] VEHICLE, ESPECIALLY TWO-WHEEL, WITH BELT DRIVE AND SWING ARM

[0002] The invention relates to a vehicle, in particular a two-wheeler, comprising (a) a frame, (b) a driven wheel, in particular a driven rear wheel, (c) a drive, in particular an electric motor, and (d) a suspension by means of which the wheel is resiliently connected to the frame. Such a vehicle can be, for example, a bicycle, in particular an off-road bicycle, an electric bicycle or a pedelec, a motorcycle, in particular an off-road motorcycle, a three-wheeler (also called a trike), or a quad.

[0003] Particularly in off-road vehicles, to which the invention also relates, it is advantageous if the driven wheel, especially the rear wheel, has a large spring travel. In such cases, chain drives are used to transfer the drive torque of the drive to the driven wheel.

[0004] Two-wheelers with belt drives are also known, but they have no or significantly less suspension. The reason for this is that it is difficult to keep the belt tension nearly constant while the suspension travels.

[0005] The invention is based on the object of reducing disadvantages in the prior art.

[0006] The invention solves the problem by a generic vehicle, in particular an electric bicycle, which has (e) a belt drive arranged to transmit a drive torque from the drive to the rear wheel and a belt, a belt tensioner arranged to exert a tensioning force on a slack side of the belt, and a driven pulley arranged concentrically to the wheel, wherein the suspension has a swing arm which is mounted in a swing arm bearing on the frame, has a free end to which the rear wheel is attached, and has a swing arm spring for pretensioning the swing arm into a rest position, wherein a drive pulley rotation axis is spaced from a swing arm instantaneous pivot axis about which the swing arm pivots.

[0007] The feature that the rear wheel is attached to the free end is understood in particular to mean that the rear wheel is directly attached to the free end, so that the rear wheel rotation axis is immobile, in particular not pivotable, relative to the free end.

[0008] The swing arm's instantaneous pivot axis is the axis of rotation around which the drive pulley's pivot axis and / or the rear wheel's pivot axis pivot during an infinitesimal pivoting movement. If the rear wheel is pivotally mounted on the frame about multiple pivot axes, the position of the swing arm's instantaneous pivot axis changes depending on the swing arm's deflection angle. If the rear wheel is pivotally mounted on the frame about only one pivot axis, the swing arm's instantaneous pivot axis is identical to this pivot axis. According to a preferred embodiment, all pivot axes around which the rear wheel is pivotally mounted on the frame run outside the rear wheel. In other words, the rear wheel is then attached directly to the free end of the swing arm and not via an adjusting lever.

[0009] Preferably, all pivot axes around which the rear wheel is pivotally mounted run outside the rear wheel. This results in a relatively simple rear wheel mounting. Naturally, the rear wheel's rotation axis runs inside the rear wheel.

[0010] The advantage of such a vehicle is that it can be particularly quiet, especially if the drive is electric. Belt drives require the most even belt tension possible to prevent belt slippage and / or damage.

[0011] To ensure that the tension in the belt drive remains as constant as possible throughout the suspension travel, the driven wheel, particularly the rear wheel, could be mounted so that it can pivot around the drive pulley's axis of rotation. However, this type of mounting generally results in comparatively less rigid vehicles, particularly two-wheelers. Because the drive pulley's axis of rotation is spaced apart from the swing arm's instantaneous pivot axis, the connection between the swing arm and the frame can be very rigid. However, it must be accepted that the distance between the driven pulley's axis of rotation and the drive pulley's axis of rotation changes during the suspension travel. However, it has been shown that this disadvantage can be compensated for by means of a belt tensioner.

[0012] For the purposes of this description, an electric bicycle is understood to be a vehicle that is at least partially powered by muscle power, in particular by means of a pedal drive, and also has an electric motor for propulsion. The electric bicycle is preferably a two-wheeled vehicle.

[0013] Preferably, the rated continuous power of the electric motor is no more than 1000 watts, in particular no more than 500 watts, in particular no more than 300 W. Such electric motors are comparatively light, so corresponding electric bicycles are also light. The simple design of the belt tensioner is therefore particularly advantageous for such electric bicycles.

[0014] According to one embodiment, the electric bicycle is a Class 1 e-bike, which can also be called a pedal-assisted e-bike. The electric motor only assists the rider when they pedal. This electric bicycle, for example, is limited to a maximum speed of 20 miles per hour or 25 km / h.

[0015] Alternatively, the electric bike is a Class 2 e-bike and features a throttle that allows the rider to control the electric motor without pedaling. This electric bike is preferably limited to a top speed of 20 mph (20 km / h) or 25 km / h.

[0016] Alternatively, the electric bicycle is a Class 3 e-bike. Such an electric bicycle can also be called a speed pedelec; the maximum speed is preferably limited to 45 km / h. The swing arm is understood to be a structure attached to the frame that allows a pivoting movement of the driven wheel relative to the frame, but prevents a change in the angle between the drive pulley's rotational axis and the driven pulley's rotational axis. The swing arm can be a single-joint swing arm, a double-joint swing arm, or a multi-joint swing arm. Accordingly, the swing arm mounting comprises one, two, or more joints or pairs of joints.

[0017] The swingarm may be designed as a single-sided swingarm, meaning the driven wheel is attached to only one side. Alternatively, the swingarm may be designed as a fork, with the driven wheel attached to both sides.

[0018] The term "suspension" refers, in particular, to a structure that, when the driven wheel pivots relative to the frame from a rest position, generates a force that counteracts this pivoting movement. It is advantageous, but not necessary, for the suspension to also be designed to dampen this pivoting movement. For this purpose, the suspension preferably comprises a shock absorber, in particular a hydraulic shock absorber.

[0019] A belt tensioner is a device that ensures that the belt tension fluctuates less during the compression and rebound of the suspension than it would without the belt tensioner.

[0020] The belt drive is preferably constructed in such a way that a spring region, when the suspension is compressed or extended, has at least one swing arm deflection angle interval in which the length of the belt travel path changes and / or the belt tension changes and / or the deflection of the belt tensioner spring changes.

[0021] Preferably, there is exactly one belt tensioner. In particular, there is preferably no belt tensioner acting on the tight side of the belt. If there is a belt tensioner acting on the tight side of the belt, it is preferably independent of the belt tensioner acting on the slack side. This means that a movement of the belt tensioner acting on the tight side does not necessarily lead to a movement of the belt tensioner acting on the slack side.

[0022] If the swing arm is mounted so that it can pivot about only one pivot axis, the swing arm's instantaneous pivot axis is the swing arm pivot axis. Whenever reference is made to the swing arm's instantaneous pivot axis in the following, the swing arm pivot axis is always included as a special case.

[0023] Preferably, the swing arm's instantaneous pivot axis runs outside the rear wheel. This specifically means that the swing arm's pivot axis does not run through the convex hull of the rear wheel. The convex hull is the set of all points that lie on a connecting line between two points on the rear wheel. Preferably, the rear wheel is pivotably mounted exclusively about the swing arm's instantaneous pivot axis. Naturally, the rear wheel is pivotably mounted about its rear wheel rotation axis. A pivotable mounting means that this mounting does not allow a 360° rotation.

[0024] Preferably, a distance between the rear wheel rotation axis and a tensioning roller rotation axis about which the tensioning roller is rotatably mounted is smaller than a distance between the rear wheel rotation axis and the swing arm instantaneous pivot axis, preferably at least 20% smaller, in particular at least 35% smaller.

[0025] A distance between the drive pulley rotation axis and the swing arm instantaneous pivot axis is, for example, at least 35 mm, in particular at least 40 mm, in particular at least 45 mm, in particular at least 50 mm, in particular at least 55 mm, in particular at least 60 mm, in particular at least 65 mm. Alternatively or additionally, the distance between the drive pulley rotation axis and the swing arm instantaneous pivot axis is at most 105 mm, in particular at most 100 mm, in particular at most 95 mm, in particular at most 90 mm, in particular at most 85 mm, in particular at most 80 mm, in particular at most 75 mm.

[0026] According to a preferred embodiment, the belt drive has a belt guide element. The belt guide element is arranged to exert a force from the inside to the outside on one running side of the belt. Preferably, the belt guide element is arranged adjacent to the swing arm's instantaneous pivot axis. Preferably, the belt guide element exerts the force on the slack side. Such a belt guide element allows the suspension to have a long spring travel without the slack side coming into contact with the swing arm bearing.

[0027] The running side of the belt is the side that is in contact with the pulleys during operation. The running side of the belt faces inward.

[0028] While it is possible to position the swing arm's momentary pivot axis at a distance from the drive pulley's rotation axis so that contact between the slack side and the swing arm bearing is always excluded, in this case, the travel of the spring leads to a significant change in the position of the belt tensioner. This, in turn, leads to a significant fluctuation in the belt tension, which is undesirable.

[0029] The swing arm mounting preferably comprises an axle, and the swing arm's instantaneous pivot axis is a swing arm rotation axis that runs through the axle. The swing arm mounting preferably has two bearings, in particular two roller bearings, particularly preferably two ball bearings, by means of which the swing arm is mounted for rotation about the axle. It is possible, but not necessary, for the belt guide element, which in this case is preferably designed as a toothless roller, to be mounted for rotation about this axle.

[0030] It is possible, but not necessary, for the belt guide element to exert the force continuously. In particular, it is sufficient if the belt guide element exerts the force in at least one position of the swing arm. Preferably, the belt guide element exerts the force over at least 70%, in particular over 80%, of the swing arm's spring travel, preferably over the entire spring travel.

[0031] Preferably, the belt guide element is in sliding or rolling friction connection with the belt.

[0032] The belt guide element can be attached to the swing arm or the frame. Preferably, the belt guide element is attached exclusively to the swing arm. The belt tensioner is preferably attached to the swing arm. Particularly preferably, the belt tensioner is attached exclusively to the swing arm. This results in a simple and robust design. Furthermore, a particularly large suspension travel can be achieved this way. This is particularly advantageous for electric bicycles that are intended to be off-road.

[0033] It is advantageous if the belt tensioner has a tensioning pulley that presses against the back of the belt. The back of the belt is opposite the running side and therefore faces outward. The back of the belt is not in contact with the drive pulley and the driven pulley.

[0034] The belt tensioner preferably has a belt tensioner spring for generating a spring force, in particular a compressive force. The belt tensioner spring can, for example, act on a pivot arm to which the tensioning pulley is attached. Alternatively, the belt tensioner spring can be directly connected to an axis around which the tensioning pulley rotates, exerting the spring force on it.

[0035] Preferably, the belt tensioner spring is attached exclusively to the swing arm. This results in a simple and robust design. If the belt tensioner has a pivot arm to which the tension pulley is attached, this pivot arm is preferably attached exclusively to the swing arm.

[0036] The pivot arm has a pivot axis that is preferably closer to the drive pulley's rotation axis than the tensioner's rotation axis. The tensioner is then pressed toward the driven pulley.

[0037] The belt tensioner spring exerts a rest spring force when the swing arm is at its maximum extension. The belt tensioner spring also exerts a limit spring force when the swing arm is at its maximum compression. The feature that the swing arm is at its maximum extension means that no external force acts on the swing arm. The swing arm is at its maximum compression in particular when no further spring travel can be covered. This is the case, for example, if the vehicle falls onto its wheels from a great height. The belt guide element is preferably arranged such that the rest spring force deviates from the limit spring force by a maximum of 60%, in particular a maximum of 55%, in particular a maximum of 50%, in particular a maximum of 45%, in particular a maximum of 40%, in particular a maximum of 35%. The smaller the deviation, the more constant the belt tension is over the spring travel, i.e. over the swing arm deflection angle.

[0038] The swing arm deflection angle is calculated as the angle between the straight line through the driven pulley's rotational axis and the swing arm's instantaneous pivot axis in the respective swing arm deflection state, and the straight line through the driven pulley's rotational axis and the swing arm's instantaneous pivot axis with the swing arm fully extended. The smallest swing arm deflection angle is 0° by definition.

[0039] The belt drive has a drive pulley with a drive pulley diameter. The driven pulley diameter is preferably at least two and a half times, in particular at least three times, the drive pulley diameter. For example, the belt is a V-belt.

[0040] According to one embodiment, the belt is a toothed belt that meshes with the driven pulley and the drive pulley. The driven pulley has a number of teeth on the driven pulley that is preferably at least two and a half times, in particular at least three times, the number of teeth on the drive pulley. This results in a reduction gear, and the motor can operate at a high rotational frequency. This allows the motor to be designed to be particularly small and lightweight.

[0041] The belt guide element deflects the belt along a deflection section of the belt. In other words, the deflection section is the path along which the slack side extends in the area where it is deflected by the belt guide element. The deflection section consists of imaginary points that are as far away from the swing arm's instantaneous pivot axis as possible, yet have no contact with the belt and are not located outside the belt. If an area exists where the belt guide element makes contact with the belt without deflecting it, this area is not part of the deflection section.

[0042] The running path of a belt describes the curved or angled path that a flexible belt follows when it runs around pulleys or rollers in a belt drive system. The belt itself is preferably made of a flexible material such as rubber or high-performance plastics. The running path is determined by the geometric arrangement of the pulleys, their size, and the tension exerted on the belt. When a belt is placed on pulleys, it naturally takes on a curved shape due to the different circumferences of the pulleys. In addition, the running path of a belt has an essentially straight shape on the way from one pulley to another. To a good approximation, a running path can be described using a series of straight lines and circular arcs. The deflection section is the part of the running path in which the belt is deflected by the belt guide element.

[0043] The deflection section has a maximum distance from the swing arm's instantaneous pivot axis. This maximum distance may depend on the swing arm's deflection angle. However, it is advantageous if the maximum distance is the same for all swing arm deflection angles.

[0044] Preferably, the maximum distance is greater than the radius of the drive pulley, in particular the maximum distance is greater than 1.1 times the tip circle radius.

[0045] Alternatively or additionally, the maximum distance is preferably smaller than an offset between the swing arm momentary pivot axis and the drive pulley rotation axis.

[0046] Preferably, the belt guide element is arranged such that it is in contact with the belt over at least 70%, in particular at least 80%, in particular at least 90%, of a swing arm deflection angle interval. The swing arm deflection angle interval begins with the smallest possible swing arm deflection angle, which by definition is 0°, and ends with the maximum swing arm deflection angle amax. The percentages refer to the angle interval. Preferably, the maximum swing arm deflection angle amax is at least 20°, in particular at least 30°, in particular at least 35°, in particular at least 45°. Preferably, the maximum swing arm deflection angle amax is at most 60°, in particular at most 55°, in particular at least 50°.

[0047] According to an alternative embodiment, the belt guide element is arranged to exert the force from the inside outward onto the running side of the belt only when the swing arm has traversed the negative spring travel or at least a portion of the negative spring travel. The term "negative spring travel" is explained below.

[0048] The running surface of a belt is the part of the belt that is in direct contact with the pulleys or rollers in a belt drive. It is the part of the belt that transfers power or movement from the driving pulley to the driven pulley. The properties and condition of the running surface are important for the performance and longevity of the belt and the efficiency of the belt drive system. The running surface of a belt is preferably made of a durable and wear-resistant material. Common materials for belt running surfaces are rubber, synthetic compounds, or other materials such as polyurethane, which ensure good frictional contact with the pulleys. The running surface of a belt can have a profile or a specific shape that is adapted to the groove or shape of the pulleys. V-belts, for example, have a V-shaped profile and run in pulleys with V-grooves.Timing belts have a tooth profile that engages with the corresponding teeth of the pulleys.

[0049] Correct belt tension within the belt is important to ensure that the running surface of the belt has good contact with the pulleys. Insufficient tension can lead to slippage, while excessive tension can cause premature wear and increased load on the bearings. An advantage of the invention is that the belt tension can be kept within the permissible limits in every operating state of the suspension and the electric drive. According to one embodiment, the negative spring travel is at least 20%, in particular at least 25%, particularly preferably at least 29%, of the swing arm deflection angle interval. Preferably, the negative spring travel is at most 35% of the swing arm deflection angle interval. The negative spring travel is the interval of the swing arm deflection angle from 0° to the normal swing arm deflection angle.The normal swing arm deflection angle is the swing arm deflection angle that occurs when a person with the design weight sits on a seat of the vehicle. The design weight is assigned to the vehicle. Preferably, the vehicle has an associated document stating the normal weight.

[0050] Sag is an important parameter in suspension setup. It indicates the amount the suspension compresses when the weight of a rider at design weight is applied to the vehicle, especially a bicycle or motorcycle. Correct sag setting is essential for optimal handling, comfort, and control. The ideal amount of sag can vary depending on the vehicle type, intended use, rider weight, and personal preference. Typically, sag should be set to approximately 25% of the total suspension travel.

[0051] Off-road vehicles, to which the invention particularly relates, often require more negative spring travel, which is in the range of 30% to 35% of the total spring travel.

[0052] The correct adjustment of the sag, combined with consistent belt tension throughout the entire travel, is crucial for a balanced and responsive ride. This ensures that the suspension is adequately loaded, allowing the bike to confidently handle bumps, curves, and other road conditions.

[0053] The belt guide element is preferably a roller. The roller preferably has no teeth. It is advantageous if the roller is arranged coaxially with the swing arm's instantaneous pivot axis. Preferably, the diameter of the roller is at least as large as the drive pulley diameter. According to one embodiment, the belt guide element has an elastomer layer mounted radially on the outside. For example, the belt guide element has an O-ring mounted radially on the outside, which is applied to a roller body. The roller body is rotatably mounted.

[0054] Preferably, the drive comprises an electric motor and a gearbox connected to the electric motor. The gearbox preferably has a gearbox output shaft coaxially connected to the drive pulley.

[0055] When the vehicle is unloaded, the transmission output shaft is preferably located above a motor rotation axis of the electric motor. Alternatively or additionally, when the vehicle is unloaded, a driven pulley rotation axis is preferably located below the drive pulley rotation axis, in particular below the motor rotation axis.

[0056] Preferably, the swing arm's instantaneous pivot axis is located below the drive pulley's rotation axis when the vehicle is unloaded. Alternatively or additionally, the driven pulley's rotation axis is located below a straight line through the drive pulley's rotation axis and the swing arm's instantaneous pivot axis when the vehicle is unloaded.

[0057] The gear shaft is preferably not coaxial with the motor shaft of the electric motor. The gear is preferably a reduction gear. The reduction ratio is preferably at least 1:2, in particular at least 1:3. The reduction ratio is preferably at most 1:6, in particular at least 1:5.

[0058] The tension pulley has a wrap angle that generally depends on the swing arm deflection angle. A rest wrap angle, which the tension pulley has when the swing arm is at its maximum extension, preferably deviates by a maximum of 30°, in particular a maximum of 20°, in particular a maximum of 15°, preferably a maximum of 10°, from a limit wrap angle, which the tension pulley has when the swing arm is at its maximum compression. Alternatively or additionally, the rest wrap angle preferably deviates by a maximum of 30°, in particular a maximum of 20°, in particular a maximum of 15°, in particular a maximum of 10°, from an extreme wrap angle, at which the function that specifies the wrap angle as a function of the swing arm deflection angle passes through a local extremum. In this way, the belt tension changes only slightly.

[0059] Preferably, the belt tensioner is arranged such that a tensioning section angle y between the slack side in a tensioning section between the tension pulley and the belt guide element on the one hand and the straight line G on the other hand, depending on the swing arm deflection angle, assumes a minimum value of at most 15°, in particular at most 10°, in particular at most 8°, in particular at most 5°. In this way, the belt tension changes only slightly over the spring travel.

[0060] It is advantageous if the slack side in the section between the tension pulley and the belt guide element runs at a deflection angle θ to a tangent T to the underside of the driven pulley and the underside of the drive pulley. This deflection angle θ is preferably at least 5°, in particular at least 8°, and particularly preferably at least 10° for at least one swing arm deflection angle. The deflection angle θ is preferably a maximum of 25°. The deflection angle θ is therefore the angle by which the slack side is deflected from the path by the belt tensioner. In this way, a large wrap angle is achieved on the driven pulley, allowing a high torque to be transmitted.

[0061] Preferably, the suspension includes a shock absorber, particularly one with hydraulic damping. The force applied by the shock absorber is added to the spring force of the swing arm spring.

[0062] It is advantageous if, when the swing arm is in its extended position, the projection of the tension pulley's rotational axis onto the straight line through the drive pulley's rotational axis is at most 0.4 times the distance from the driven pulley's rotational axis to the swing arm's instantaneous pivot axis to the driven pulley's rotational axis. In other words, the tension pulley is closer to the driven pulley than to the drive pulley, allowing for a large wrap angle on the driven pulley.

[0063] Preferably, a clamping angle Q, which is the angle between the slack strand in the clamping section A and the straight line G through the drive pulley rotation axis Ü36 and the swing arm instantaneous pivot axis S32, is at most 13°, in particular at most 8°.

[0064] The invention is explained in more detail below with reference to the accompanying drawings.

[0065] Figure 1 shows a vehicle according to the invention in a scale view according to a first embodiment in the form of an electric motorcycle,

[0066] Figure 2a is a detailed view of the vehicle according to Figure 1,

[0067] Figure 2b shows a cross-section according to Figure 2a,

[0068] Figure 3 a schematic view of the belt drive

[0069] Figure 4a shows the running path of the belt when the swing arm is fully extended,

[0070] Figure 4b the running side of the belt according to Figure 4a, when the swing arm is completely compressed,

[0071] Figure 5a shows a section of a vehicle according to the invention in a scale view according to a second embodiment in the form of an electric bicycle,

[0072] Figure 5b shows a section of the view according to Figure 5a and

[0073] Figure 6 shows the dependence of the tension pulley wrap angle ß on the swing arm pivot angle α. Figure 1 shows a vehicle 10 according to the invention in the form of a motorcycle 11, which has a frame 12 and a driven wheel 14, in the present case in the form of a driven rear wheel, as well as a drive 16. By means of a suspension 18, the wheel 14 is resiliently mounted on the frame 12. The drive 16 has an electric motor 20. The wheel 14 is driven by the electric motor 20 by means of a belt drive 22. The electric motor has a motor rotation axis D20.

[0074] The belt drive 22 has a belt 24, a driven pulley 26 and a belt tensioner 28 for tensioning the belt 24. For this purpose, the belt tensioner 28 exerts a force on a slack strand 30.

[0075] The suspension 18 has a swing arm 32, which is attached to the frame 12 in a swing arm bearing 34. The swing arm bearing 34 enables a driven pulley rotation axis D26 to pivot along a trajectory curve B26. The swing arm 32 pivots about a swing arm instantaneous pivot axis S32. Since the swing arm 32 is mounted in a pivot bearing 35 in the embodiment shown in Figure 1, the swing arm instantaneous pivot axis is a swing arm pivot axis. The driven pulley rotation axis D26 corresponds to a wheel rotation axis D14 of the driven wheel 14. In particular, the wheel rotation axis D14 in the present case is the rear wheel rotation axis. It can be seen that the swing arm instantaneous pivot axis S32 lies outside the rear wheel 14.

[0076] The belt drive 22 has a drive pulley 36 that rotates about a drive pulley rotation axis D36. The drive pulley 36 is driven by the motor 20.

[0077] A swing arm spring 37 preloads the swing arm 32 into a rest position shown in Figure 1, in which no external forces act on the wheel 14. Such a case occurs, for example, when the vehicle 10 is hanging. In this case, the swing arm deflection angle a = ao = 0°. A straight line Ga = 0° (= Go°) through the driven pulley rotation axis D36 and the swing arm instantaneous pivot axis S32 runs in this state as shown in Figure 1. If the swing arm spring 37 compresses, this leads to the straight line Ga' through the driven pulley rotation axis D36 and the swing arm instantaneous pivot axis S32. The swing arm deflection angle a' is the angle between the straight lines Go° and Ga'. Figure 2a shows that the belt tensioner 28 can be attached to the rocker 32 and can have a tension roller 40 which presses against a belt back 42 which is opposite a running side 43.The belt tensioner 28 may have a belt tensioner spring 44 which acts on a pivot arm 46 to which the tension pulley 40 is attached.

[0078] Regardless of the other described features of the embodiment, it is advantageous if the belt tensioner spring 44 exerts a compressive force on the pivot arm 46 that runs at least substantially parallel to the slack side 30 in the region between the tensioning roller 40 and the drive pulley 36. This is understood in particular to mean that an angle between the vector of the compressive force and the slack side in this region is at most 15°, in particular 10°, preferably at most 5°.

[0079] The vehicle 10 (here: the motorcycle 11) preferably has a battery 48 connected to the motor 20 for supplying electrical energy. The drive 16 may include a transmission 50 driven by the motor 20, which in turn drives the drive pulley. A transmission rotation axis D50 preferably corresponds to the drive pulley rotation axis D36.

[0080] Figure 2b shows the view AA from Figure 2a through the one axle 52, which is rigidly attached to the frame 12. The swing arm 32 is rotatably mounted by means of two roller bearings 54.1, 54.2 and an axle 52. A shock absorber 56 of the suspension 16 can be seen behind the axle 32.

[0081] Figure 2b shows a belt guide element 58 attached to the rocker arm 32. In the present case, the belt guide element 58 is designed as a sliding element on which the belt 24 is guided. Alternatively, the belt guide element 58 can be designed as a roller. This roller can be rotatably mounted on the axle 52. The belt guide element 58 is arranged adjacent to the rocker arm's instantaneous pivot axis S32.

[0082] The following components of the embodiment of the vehicle 10 shown in Figure 1 are optional: The vehicle 10 can have a second wheel, in particular a front wheel 60, a wheel suspension 62, in particular a wheel fork and a handlebar 64 and a seat 66 for a driver.

[0083] Figure 3 shows a schematic view of a running path P of the belt 24 with the slack side 30 and a tight side 68. The drive pulley 36 has a drive pulley diameter d36, and the driven pulley 26 has a driven pulley diameter d26. Preferably, d36 / d26 > 2.

[0084] The schematically drawn belt guide element 58 causes a deflection of the belt 24. The area in which this deflection takes place is called deflection section U. This deflection section U has a distance a(a) from the swing arm instantaneous pivot axis S32, which can change with the swing arm pivot angle a, but does not have to change, and has a maximum distance a ma x. This maximum distance a max is preferably greater than 1.1 times a radius rse = dse / 2 of the drive pulley 36. It is advantageous if an offset V between the swing arm momentary pivot axis S32 and the drive pulley rotation axis D36 is greater than the maximum distance a ma x.

[0085] Figure 3 shows that the tension pulley 40 has a tension pulley wrap angle ß. The tension pulley wrap angle ß is the angle formed by the circumferential area of ​​the tension pulley 40 that is in contact with the slack side 30. The tension pulley wrap angle ß depends on the swing arm pivot angle α. The tension pulley wrap angle β at a = 0° is the rest wrap angle β0. The tension pulley wrap angle β max to the maximum swing angle a ma x is the limit wrap angle ß ma x.

[0086] The mathematical function ß(a), which specifies the tension roller wrap angle ß as a function of the swing arm pivot angle a, is shown in Figure 6 and passes through a local extremum ßext, which is called the extreme wrap angle.

[0087] It is advantageous if the tension pulley wrap angle does not change too much with varying swing angles α. Preferably, the difference between the rest wrap angle β0 and the limit wrap angle is at most 30°, preferably at most 20°, and / or the difference between the rest wrap angle β0 and the extreme wrap angle is also at most 20°, preferably at most 10°.

[0088] A tensioning section A of the running path P runs between the tensioning roller 40 and the deflection section U. The tensioning section A runs at a tensioning section angle y to the load strand 68. It is advantageous if the tensioning section angle y is at most 15°, in particular at most 10°.

[0089] The clamping angle 0 is defined as the angle between the slack side in the clamping section A and the straight line G through the drive pulley rotation axis Ü36 and the swing arm instantaneous pivot axis S32. The design is advantageous if the clamping angle 0 is at most 13°, in particular at most 8°.

[0090] The deflection section U runs at a deflection angle ö to a tangent T to the underside of the driven belt pulley 26 and the underside of the drive belt pulley 36. The greater the deflection angle ö, the more the belt tensioner 28 changes the running path P. Preferably, the deflection angle is at least ö = 10° when the rocker arm 32 is maximally compressed.

[0091] Figure 4a shows the travel path P in a scale representation in the state when the swing arm 32 is fully extended, i.e. for the swing arm pivot angle ao.

[0092] Figure 4b shows the travel path P in the state where the swing arm runs horizontally.

[0093] Figure 4c shows the travel path P in the state when the swing arm 32 is fully compressed, i.e. for the swing arm pivot angle a ma x.

[0094] Figure 5 shows a section of a vehicle 10 according to the invention in the form of a motorcycle 11, in which the swing arm spring 37 acts on a pivot lever 70. The motorcycle 11 has a battery 70 that supplies the electric motor 20 with electrical energy. A motor shaft 72 of the electric motor 20 drives the transmission 50. A transmission output shaft 74 of the transmission drives the drive pulley 36.

[0095] The belt guide element 58, which is designed as a gear but can also be designed as a roller, is in contact with a belt running surface 76 of the belt 24.

[0096] Shown is a projection p4o of a tension pulley rotation axis Ü4o onto the straight line G through the drive pulley rotation axis D36 and the swing arm instantaneous pivot axis S32. This projection p4o, i.e. a point on the straight line G, has a distance A in the extended state of the swing arm 32. P 4O-D26 to the driven pulley rotation axis D26. This distance A P 4O-D26 is preferably at most 0.4 times the distance from the driven pulley rotation axis Ü26 to the swing arm instantaneous pivot axis S32.

[0097] Figure 6 shows the relationship between the tension pulley wrap angle ß and the swing arm pivot angle α. The corresponding values ​​can be found in the following table.

[0098]

[0099] List of reference symbols

[0100] 10 Vehicle 86 Auxiliary pulley

[0101] 12 frames

[0102] 14 Wheel, rear wheel a Swing arm swivel angle

[0103] 16 Drive ao minimal swing arm swivel

[0104] 18 Suspension angle (swing arm fully extended)

[0105] 20 Motor, electric motor amax maximum swing arm swivel

[0106] 22 Belt drive angle (swing arm maximum

[0107] 24 belts spring)

[0108] 26 Driven pulley ß Tension pulley wrap¬

[0109] 28 Belt tensioner swinkel ßo Rest wrap angle

[0110] 30 Slack strand ßext Extreme wrap angle

[0111] 32 Swing arm ßmax limit wrap angle

[0112] 34 Swing arm bearing y clamping section angle

[0113] 35 pivot bearing 5 deflection angle

[0114] 36 Drive pulley cp Angle of the straight line G to the horizontal

[0115] 37 Wing spring zontalen

[0116] 38 Front wheel 0 Clamping angle a Distance from the deflection section

[0117] 40 Tension pulley for swing arm momentary

[0118] 42 Belt back swivel axis

[0119] 43 Running side amax maximum distance

[0120] 44 Belt tensioner spring A tensioning section

[0121] 46 Swivel arm d36 Drive pulley diameter

[0122] 48 Accumulator diameter d26 Driven pulley diameter

[0123] 50 gear knives

[0124] 52 axis dss belt guide diameter

[0125] 54 rolling bearings Du wheel pivot axis, rear wheel pivot

[0126] 56 shock absorber axle

[0127] 58 Belt guide element D20 Motor rotation axis

[0128] D26 Driven pulley rotating

[0129] 60 front wheel axle

[0130] 62 Wheel suspension D36 Drive pulley-

[0131] 64 Handlebar rotation axis

[0132] 66 Seat D40 Tensioner roller rotation axis

[0133] 68 Load strand F spring force

[0134] G Straight

[0135] 70 Battery H Horizontal

[0136] 72 Motor shaft L direction of rotation

[0137] 74 Gearbox output shaft P4o projection

[0138] 76 Belt running surface P Running path

[0139] 78 Electric bicycle crank S32 swing arm momentary pivot axis

[0140] 80 crank T tangent

[0141] 82 Pedals U Deflection section

[0142] 84 Pedal pulley

Claims

Patent claims 1. Vehicle (10), in particular a two-wheeler, with (a) a frame (12), (b) a driven wheel (14), in particular a driven rear wheel, (c) a drive (16), in particular with an electric motor (20), and (d) a suspension (18) by means of which the wheel (14) is resiliently connected to the frame (12), characterized by (e) a belt drive (22) which (i) is arranged to transmit a drive torque from the drive (16) to the wheel (14) and (ii) a drive pulley (36), (iii) a belt (24), (iv) a belt tensioner (28) arranged to exert a tensioning force on a slack side (30) of the belt (24), and (v) a driven pulley (26) arranged concentrically with the wheel (14), (f) wherein the suspension (18) comprises a rocker (32), (i) which is mounted in a swing arm bearing (34) on the frame (12), (ii) has a free end to which the wheel (14) is attached, and (iii) a rocker spring (37) for pre-tensioning the rocker (32) in a rest position, (g) wherein a drive pulley rotation axis (Dse) is spaced from a swing arm instantaneous pivot axis (S32) about which the swing arm (32) pivots.

2. Vehicle (10) according to claim 1, characterized in that the belt drive (22) has a belt guide element (58) which (i) is arranged adjacent to the swing arm momentary pivot axis (S32) and (ii) is arranged to exert a force from the inside outwards on a running side (43) of the belt (24).

3. Vehicle (10) according to one of the preceding claims, characterized in that (a) the belt tensioner (28) is attached exclusively to the swing arm (32), (b) has a tensioning roller (40) which presses against a belt back (42) of the belt (24) and (c) the belt tensioner (28) has a belt tensioner spring (44), in particular a compression spring, for generating a spring force (F).

4. Vehicle (10) according to one of the preceding claims, characterized in that all pivot axes about which the rear wheel (14) is pivotally mounted run outside the rear wheel (14).

5. Vehicle (10) according to claim 3 or 5, characterized in that (a) the belt tensioner spring (44) exerts a rest spring force when the rocker (32) is maximally extended and exerts a limit spring force when the rocker (32) is maximally compressed, and (b) the belt guide element (58) is arranged such that the rest spring force deviates from the limit spring force by a maximum of 60%, preferably 35%.

6. Vehicle (10) according to one of the preceding claims, characterized in that the belt drive (22) (a) has a drive pulley (36) and a driven pulley diameter (d26) is at least two and a half times, in particular at least three times, a drive pulley diameter (d36) and / or (a) the belt (24) is a toothed belt connected to the driven pulley (26) and the drive pulley (36), and a number of teeth of the driven pulley (26) is at least two and a half times, in particular at least three times, the number of teeth of the drive pulley.

7. Vehicle (10) according to one of claims 2 to 5, characterized in that (a) the belt guide element (58) causes a deflection of the belt (24) along a deflection section (U) of the belt (24) (b) the deflection section (U) in the region of the belt guide element (58) has a maximum distance (a ma x) of a swing arm momentary pivot axis (S32), the (i) is greater than the radius of the drive pulley (36), preferably greater than 1.1 times the radius of the drive pulley (36) and (ii) is smaller than an offset between the swing arm instantaneous pivot axis (S32) and the drive pulley rotation axis (D36), preferably smaller than the drive pulley diameter (dse).

8. Vehicle (10) according to one of claims 2 to 6, characterized in that (a) the belt guide element (58) is arranged to exert the force from the inside to the outside on the running side (43) of the belt (24) only when the rocker (32) is deflected by more than a predetermined rocker deflection angle, and / or (b) the belt guide element (58) is arranged such that it has contact with the belt (24) over at least 70%, in particular at least 80%, in particular 90% of a swing arm deflection angle interval.

9. Vehicle (10) according to one of claims 2 to 7, characterized in that the belt guide element (58) is a roller, wherein the roller is preferably arranged coaxially to the swing arm instantaneous pivot axis (S32) and a belt guide element diameter (dss) is at least as large as half the drive belt pulley diameter (dse), in particular at least as large as the drive belt pulley diameter (dse).

10. Vehicle (10) according to one of the preceding claims, characterized in that (a) the drive (16) comprises an electric motor (20) and a gearbox (50), and the gearbox (50) comprises a gearbox output shaft (74) which is coaxially connected to the drive pulley (36), and (b) when the vehicle is unladen (10) (i) a transmission output shaft (74) is located above a motor rotation axis of the electric motor (20) and / or (ii) a driven pulley rotation axis is located below the drive pulley rotation axis (D36), in particular below the motor rotation axis (D20), and / or (iii) the swing arm momentary pivot axis (S32) is below the drive pulley rotation axis (D36) and / or (iv) the driven pulley rotation axis (D26) lies below a straight line (G) through the drive pulley rotation axis (D36) and the swing arm instantaneous pivot axis (S32).

11. Vehicle (10) according to one of the preceding claims, characterized in that (a) the tensioning roller (40) has a tensioning roller wrap angle (ß) which depends on the swing arm deflection angle (a), (b) the rest wrap angle (ßo), when the rocker (32) is at its maximum extension, deviates by a maximum of 40°, preferably by a maximum of 27°, from a limit wrap angle (ßmax) when the rocker (32) is at its maximum compression and / or (c) Rest wrap angle (ßo) deviates by a maximum of 40°, preferably by a maximum of 27°, from an extreme wrap angle (ßext) at which the function which indicates the wrap angle as a function of the swing arm deflection angle (α) passes through a local extremum.

12. Vehicle (10) according to one of the preceding claims, characterized in that the slack side (30) assumes a position within the compression movement in which it runs in a tensioning section (A) between the tensioning roller (40) and the belt guide element (58) at a tensioning section angle (y) of at most 15°, preferably at most 10°, to the load side (68).

13. Vehicle (10) according to one of the preceding claims, characterized in that (a) the slack strand (30) in the deflection section (U) runs at a deflection angle (6) to a tangent (T) to an underside of the driven pulley (26) and an underside of the drive pulley (36), (b) the deflection angle (6) is at least 10° when the rocker arm (32) is maximally compressed, 14. Vehicle (10) according to one of the preceding claims, characterized in that the suspension (18) has a shock absorber (56), in particular with hydraulic damping.

15. Vehicle (10) according to one of the preceding claims, characterized in that in the rebounded state of the rocker (32) a projection (p4o) of the tensioning roller rotation axis (Ü4o) onto the straight line (G) through the drive pulley The rotation axis (D36) has a distance of at most 0.4 times the distance from the driven pulley rotation axis (D26) to the swing arm instantaneous pivot axis (S32) to the driven pulley rotation axis (D26).

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