Freewheel of a Vehicle

Abstract

A freewheel of a vehicle, in particular a two-wheeler, includes (i) a first shaft, (ii) a second shaft having a first gear cog, (iii) a freewheel element having a second gear cog, and (iv) a friction element. The first gear cog and the second gear cog are configured to, when engaged with each other, effect a torque transfer between the second shaft and the freewheel element. The freewheel element is arranged to be displaceable in an axial direction on the first shaft. The freewheel element is arranged to be non-rotatable relative to the first shaft in the circumferential direction. The freewheel element and the friction element are connected to one another by way of a helical mechanism which is configured to effect a translational displacement of the freewheel element and the friction element relative to one another when the freewheel element and friction element rotate relative to one another.

Claims

1. A freewheel of a vehicle, comprising: a first shaft; a second shaft including a first gear cog; a freewheel element including a second gear cog; and a friction element, wherein the first gear cog and the second gear cog are configured to, when engaged with each other, effect a torque transfer between the second shaft and the freewheel element, wherein the freewheel element is arranged to be displaceable in the axial direction on the first shaft, wherein the freewheel element is arranged to be non-rotatable relative to the first shaft in the circumferential direction, and wherein the freewheel element and the friction element are connected to each other by way of a helical mechanism which is configured to effect a translational displacement of the freewheel element and the friction element relative to each other during relative rotation of the freewheel element and the friction element.

2. The freewheel according to claim 1, wherein the helical mechanism includes a thread.

3. The freewheel according to claim 2, wherein the thread is designed not to be self-inhibiting.

4. The freewheel according to claim 1, further comprising a return element which is arranged and configured to apply a return force to the freewheel element, wherein: the return force is oriented towards the first gear cog of the second shaft.

5. The freewheel according to claim 4, wherein the force closure, the helical mechanism, and the return element are designed such that a disengaging force caused by the force closure and the helical mechanism when the freewheel element and the friction element rotate relative to one another is greater than the return force of the return element.

6. The freewheel according to claim 1, wherein the return element is an axial spring disc.

7. The freewheel according to claim 1, wherein a predetermined friction closure in the circumferential direction is formed between the second shaft and the friction element.

8. The freewheel according to claim 7, wherein: the force closure between the second shaft and the friction element includes a friction force in the circumferential direction, and/or the force closure between the second shaft and the friction element includes a magnetic force.

9. The freewheel according to claim 1, further comprising a stop configured to limit the translational displacement of the freewheel element relative to the friction element.

10. The freewheel according to claim 9, wherein the reset member is arranged between the stop and the freewheel element.

11. The freewheel according to claim 9, wherein the stop is designed such that, when the freewheel element adjoins the stop, the gear cogs are completely disengaged from one another.

12. The freewheel according to claim 1, wherein the helical mechanism is designed such that the corresponding relative translational displacement during relative rotation in the freewheel direction disengages the tooth engagement of the gear cog and, during relative rotation in the locking direction, engages the tooth engagement of the gear cogs.

13. The freewheel according to claim 1, wherein the friction element is attached to the second shaft in an axially non-displaceable manner.

14. The freewheel according to claim 1, wherein the freewheel element is attached to the first shaft in an axially displaceable manner and in a non-rotatable manner in the circumferential direction by way of a radial gear cog.

15. A vehicle, comprising a freewheel according to claim 1.

16. The vehicle according to claim 15, further comprising: a drive unit connected to the second shaft, and a crank drive connected to the first shaft.

17. The freewheel according to claim 1, wherein the vehicle is a two-wheeler.

18. The vehicle according to claim 15, wherein the vehicle is an electric bike.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The disclosure is described in the following with reference to exemplary embodiments in conjunction with the drawings. In the drawings, functionally identical components are identified with respectively identical reference characters. Shown are:

[0029] FIG. 1 a simplified schematic view of a vehicle comprising a freewheel according to a preferred embodiment of the disclosure,

[0030] FIG. 2 a detailed sectional view of a drive of the vehicle of FIG. 1, and

[0031] FIG. 3 a perspective view of the drive shown in FIG. 2.

DETAILED DESCRIPTION

[0032] FIG. 1 shows a simplified schematic view of a vehicle 100 comprising a freewheel 1 according to a preferred embodiment of the disclosure. The vehicle 100 is a vehicle 100 that can be operated with muscle power and/or motor power, in detail an electric bike.

[0033] The vehicle 100 comprises a drive unit 102 having a motor, in particular an electric motor. The motor can be powered using electrical energy by means of an electrical energy storage means 109 of the vehicle 100.

[0034] The drive unit 102 is arranged in the area of a bottom bracket of the electric bike 100. A motor torque generated by the motor can be used to provide motorized support for the pedaling force generated by the muscle power of a rider of the electric bike 100.

[0035] The muscle power of the driver can in this case be applied to a crankshaft (not shown) via a crank drive 104 which has cranks. The crankshaft is in this case arranged coaxially to a first shaft 2 and is in particular connected to the first shaft 2 in a torque transmitting manner. The first shaft 2 extends along a crank axis 15 and is arranged coaxially to a second shaft 3 (see FIGS. 2 and 3). The second shaft 3 is connected to the drive unit 102 in a torque transmitting manner. The second shaft 3 is a gear, to which, e.g., a torque from another gear, e.g. a transmission, of the drive unit 2 can be transferred.

[0036] The drive unit 102 can in this case drive the second shaft 3 by means of the generated motor torque. The second shaft 3 is arranged coaxially to the first shaft 2. A bearing 50 is in this case arranged between the first shaft 2 and the second shaft 3 to enable relative rotation. The bearing 50 can, e.g., be axially fixed to the first shaft 2 in an axially non-rotatable manner by means of a securing ring 51.

[0037] A freewheel 1 is provided between the first shaft 2 and the second shaft 3, which can produce or interrupt a torque transfer between the first shaft 2 and the second shaft 3, depending on the relative direction of rotation of the first shaft 2 and the second shaft 3.

[0038] The exact operation and design of the freewheel 1 is described in detail hereinafter with respect to FIGS. 2 and 3.

[0039] The freewheel 1 comprises a freewheel element 4 and a friction element 5, which are arranged substantially coaxially to the first 2 and second shaft 3.

[0040] The freewheel element 4 is in this case designed to be disc-shaped and is arranged directly on an outer circumference of the first shaft 2. By means of radial gear cogs 8 which can, e.g., be arranged in the form of a helical toothed spline shaft connection, the freewheel element 4 is arranged on the first shaft 2 to be displaceable in the axial direction und unable to rotate in the circumferential direction.

[0041] The freewheel element 4 comprises second front gear cogs 12 on a front axial face. First front gear cogs 11 are formed on the second shaft 3, in particular on a radially outwardly projecting flange of the second shaft 3. The first front gear cogs 11 and the second front gear cogs 12 are configured to effect torque transfer when engaged with each other.

[0042] In other words, when the freewheel element 4 is displaced to the right (in the direction indicated by arrow A in FIG. 2) towards the first front gear cogs 11 until the two front gear cogs 11, 12 engage with each other, a torque transfer between the second shaft 3 and the freewheel element 4 is enabled. The radial gear cogs 8 between the freewheel element 4 and the first shaft 2 thus also enables torque transfer between the first shaft 2 and the second shaft 3 via the freewheel element 4. This state in which the two front gear cogs 11, 12 engage with each other will be referred to as the engaged state of the gear cogs.

[0043] When the freewheel element 4 is displaced to the left (away from the first front gear cog 11 in the direction indicated by arrow B) in FIG. 2) until the two front gearings 11, 12 no longer engage with each other, the torque transfer between the second shaft 3 and the freewheel element 4, and thus also between the first shaft 2 and the second shaft 3, is interrupted. This state in which the two front gear cogs 11, 12 do not engage with each other will be referred to as the disengaged state of the gear cog.

[0044] The engagement and disengagement of the gear cog is therefore caused by the translational displacement of the freewheel element 4 along the axial direction relative to the second shaft 3, and in particular also relative to the first shaft 2.

[0045] This translational displacement of the freewheel element 4 is in this case effected as a function of a relative rotation of the first shaft 2 and the second shaft 3 in a specific rotational apparatus and by the friction element 5, as described hereinafter.

[0046] The friction element 5 is designed as a hollow shaft, or substantially sleeve-shaped, and is arranged radially outside of the first shaft 2 and a part of the freewheel element 4. The friction element 5 is in this case attached to the second shaft 3 in an axially non-rotatable manner, in which case relative rotation between the friction element 5 and the second shaft 3 is possible. In this case, however, a predetermined friction closure in the circumferential direction in the form of a friction closure formed between the friction element 5 and the second shaft 3, which closure causes the friction element 5 to rotate with the second shaft 3 if the friction closure is not overcome.

[0047] The freewheel 1 also comprises a helical mechanism 6, which is formed between the freewheel element 4 and the friction element 5. In the exemplary embodiment shown, the helical mechanism 6 in this case comprises a thread between a radially inner side of the friction element 5 and a radially outer side of the freewheel element 4. The thread of the helical mechanism 6 is in this case designed such that, during relative rotation of the first shaft 2 in the locking direction C, it causes the gear cog to engage, i.e., the tooth engagement of the two front gear cogs 11, 12 by displacing the freewheel element 4 in the direction of arrow A (see FIG. 2). In a similar manner, during relative rotation of the first shaft 2 in the opposite freewheel direction D, the disengagement of the gear cog, i.e., the release of the tooth engagement of the two front gear cogs 11, 12 is effected by displacing the freewheel element 4 in the direction of arrow B.

[0048] The freewheel 1 in this case also comprises a stop 7, which limits the axial displacement of the freewheel element 4 relative to the friction element 5. The stop 7 is formed on the second shaft 2.

[0049] When the freewheel element 4 is displaced far enough that the stop 7 is reached, the friction closure between the friction element 5 and the second shaft 3 is overcome during further relative rotation of the first shaft 2 in the freewheel direction D so that the friction element 5 and the second shaft 3 rotate relative to each other.

[0050] The freewheel further comprises a return element 9, which is arranged in the axial direction between the stop 7 and the freewheel element 4. The return element 9 is in this case designed as an axial spring disc. In detail, the return element 9 comprises a disk-shaped base region that adjoins the stop 7 and a plurality of spring fingers protruding from the base region radially inward and towards the freewheel element 4 that adjoin the freewheel element 4.

[0051] The return element 9 is in this case configured to apply a return force 90 on the freewheel element 4 by means of a spring force of the spring fingers. The freewheel element 4 is thereby pushed by the return element 9 towards the first front gear cogs 11 at any time.

[0052] The components of the freewheel 1, in detail the return element 9, the helical mechanism 6, and the force closure between the second shaft 3 and the friction element 5, are in this case designed such that a disengaging force is generated by the helical mechanism 6 and the force closure when the freewheel element 4 and friction element 5 rotate relative to one another in the freewheel direction, which force disengages the two gear cogs 11, 12 and which is greater than the return force 90. As a result, it is reliably ensured that the interruption of the torque transfer by the freewheel 1 when the freewheel element 4 and the friction element 5 rotate relative to one another in the freewheel direction.

[0053] If, in the disengaged state of the two gear cogs 11, 12, i.e., if they are not engaged with one another, the relative rotation of the freewheel element 4 and the friction element 5 stops, so the disengaging force of the helical mechanism 6 and force closure is also stopped. In this case, the return force 90 of the return element 9 causes the freewheel element 4 to be moved immediately towards the first gear cogs 11 such that the two gear cogs 11, 12 are immediately re-engaged with one another.

[0054] The movement of the freewheel element 4 by the return force 90 of the return element 9 is enabled by the thread of the helical mechanism 6 being designed not to be self-inhibiting. The return element 9 can thereby displace the freewheel element 4 axially relative to the friction element 5 when a disengaging force is no longer present.

[0055] By immediately re-engaging the front gear cogs 11, 12 immediately after the end of the rotation in the freewheeling direction, the torque transfer can be automatically restored, whereby a particularly low reaction time of the freewheel 1 can be provided.

[0056] It should be noted that, further preferably, a freewheel 1 can also be provided without the described reset element 9. Such a freewheel 1 is characterized by a particularly simple and inexpensive design. Preferably, a securing ring (not shown) can in this case be used as a stop 7. The locking of the freewheel 1 is in this case achieved by the front gear cogs 11, 12 being re-engaged by moving the freewheel element 4 by means of the helical mechanism 6.