CAGE FREEWHEEL

Abstract

A cage freewheel for installing in the clamping gap between a shaft and a hub, in particular in the drive of an e-bike, having a sprag cage which, in one embodiment, is fitted continuously in the circumferential direction with sprags arranged pivotably in the sprag cage, with the sprags being loaded resiliently in the engagement direction. Here, a bearing disk is arranged axially adjacent to the sprag cage. In a further embodiment, the cage ring is fitted consecutively in the circumferential direction both with bearing rollers (4) and with sprags (5). In addition, a shaft and hub arrangement and to an e-bike drive having a cage freewheel with the abovementioned features is also provided.

Claims

1. A cage freewheel for installing in a clamping gap between a shaft and a hub, the cage freewheel comprising: a sprag cage (3) which is configured to fit in a circumferential direction in the clamping gap; sprags (5) arranged pivotably in the sprag cage (3), with the sprags (5) being loaded resiliently in an engagement direction; and a bearing disk (7) arranged axially adjacent to the sprag cage (3).

2. The cage freewheel as claimed in claim 1, wherein the sprag cage (3) is continuously fitted in the circumferential direction with the sprags (5) arranged pivotably in the sprag cage (3).

3. The cage freewheel as claimed in claim 2, wherein bearing disk (7) and the sprag cage (3) are connected via a latching connection intermeshing at least in sections with a form-fit.

4. The cage freewheel as claimed in claim 3, wherein the bearing disk (7) is rotatable relative to the sprag cage (3) and is locked in an axial direction.

5. The cage freewheel as claimed in claim 3, wherein the latching connection has a dovetail-shaped, hook-shaped or mushroom-shaped latching profile extending in the circumferential direction.

6. The cage freewheel as claimed in claim 5, wherein the latching profile is comprises a concentric and continuous ring or ring that is interrupted in sections.

7. The cage freewheel as claimed in claim 5, wherein the latching connection has a recess which is formed in the bearing disk (7) and runs continuously in the circumferential direction of the bearing disk (7) or is segmented in the circumferential direction.

8. The cage freewheel as claimed in claim 5, wherein the latching profile is formed on the sprag cage (3) and grips behind a recess of the bearing disk (7) radially from an inside outward.

9. The cage freewheel as claimed in claim 2, wherein the bearing disk (7) is configured to be fixed to the shaft or hub and is rotatable in relation to a respective other of the shaft or the hub.

10. The cage freewheel as claimed in claim 2, wherein the bearing disk (7) comprises a plain bearing.

11. The cage freewheel as claimed in claim 2, wherein the sprags (5) are mounted captively in the sprag cage (3).

12. A shaft and hub arrangement, comprising: a hub (2); a shaft (1) which is rotatable relative to the hub; a cage freewheel arranged in a clamping gap between the shaft and the hub, the cage freewheel including a sprag cage (3) which is located in a circumferential direction in the clamping gap, sprags (5) arranged pivotably in the sprag cage (3), with the sprags (5) being loaded resiliently in an engagement direction, and a bearing disk (7) arranged axially adjacent to the sprag cage (3); and on one side adjacent to the cage freewheel there is a rolling contact bearing or plain bearing configured as a radial bearing and via which the shaft (1) and the hub (2) are mounted against each other.

13. The shaft and hub arrangement as claimed in claim 12, wherein the bearing disk (7) of the cage freewheel is fixed to the shaft (1) or the hub (2) and is rotatable in relation to an other of the shaft or the hub.

14. The cage freewheel as claimed in claim 1, wherein the sprag cage (3, 13) is fitted consecutively in the circumferential direction with bearing rollers (4) and with sprags (5), and the sprags (5) are loaded resiliently in the engagement direction.

15. The cage freewheel as claimed in claim 14, wherein the freewheel cage (3, 13) has at least one axially projecting protrusion (3b, 13b) which engages with a form-fit in the axially adjacent bearing disk (7, 17) fixed in an axial direction, and is rotatable in relation thereto, but is locked in an axial direction.

16. The cage freewheel as claimed in claim 15, wherein the at least one axial protrusion (3b, 13b) of the freewheel cage (3, 13) has a dovetail-shaped, hook-shaped or mushroom-shaped cross section and grips radially behind a corresponding recess (7a, 17a) of the bearing disk (7, 17).

17. The cage freewheel as claimed in claim 16, wherein the at least one axial protrusion (3b, 13b) of the freewheel cage (3, 13) comprises a concentric and continuous ring or ring which is interrupted in sections.

18. The cage freewheel as claimed in claim 16, wherein the recess (7a, 17a) in the bearing disk (7, 17) runs continuously in the circumferential direction or is segmented in the circumferential direction.

19. The cage freewheel as claimed in claim 16, wherein the at least one axial protrusion (3b, 13b) of the freewheel cage (3, 13) grips behind the recess (7a, 17a) in the bearing disk (7, 17) radially from an inside outward.

20. The cage freewheel as claimed in claim 15, wherein the bearing disk (7, 17) is fixed to an adjacent shaft part or hub part (1, 2) and is rotatable in relation to an other of the shaft or the hub.

21. The cage freewheel as claimed in claim 15, wherein the bearing disk (7, 17) comprises a plain bearing.

22. The cage freewheel as claimed in claim 20, wherein the bearing disk (7, 17) is mounted rotatable on the shaft part or the hub part (1 or 2) via a rolling contact bearing.

23. The cage freewheel as claimed in claim 14, wherein the spring loading of the sprags (5) is provided via a spring ring (6) which is arranged concentrically with respect to the freewheel cage (3, 13) and loads the sprags (5) in the engagement direction by spring tongues (6a) of the spring ring.

24. The cage freewheel as claimed in claim 14, wherein the bearing rollers (4) and the sprags (5) are mounted captively in the freewheel cage (3, 13).

25. The cage freewheel as claimed in claim 14, wherein the freewheel cage (3, 13) has a concentrically arranged supporting ring (23, 33) configured for additionally mounting the sprags (5) and the bearing rollers (4).

26. An e-bike drive comprising: a drive shaft (1) with a bottom bracket (42), a sprocket (40), and a crankset (41), the drive shaft (1) being connected via a freewheel to a gearwheel (43) which, in turn, is attached via a reduction gearing (44) to an electric motor (45), the freewheel having a freewheel cage (3) which is fitted consecutively in a circumferential direction both with bearing rollers (4) and with sprags (5), and the sprags are loaded resiliently in a cranking direction, and the freewheel cage (3) has at least one axially projecting protrusion (3b) which engages in a form-fitting manner in an axially adjacent bearing disk (7) fixed in an axial direction, and is rotatable in relation thereto, but is locked in the axial direction.

27. The e-bike drive as claimed in claim 26, wherein the at least one axial protrusion (3b, 13b) of the freewheel cage (3, 13) has a dovetail-shaped, hook-shaped or mushroom-shaped cross section and grips radially behind a corresponding recess (7a, 17a) of the bearing disk (7, 17).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Further details and features of the invention emerge from the description below of four exemplary embodiments with reference to the drawings, in which:

[0035] FIG. 1 shows a shaft and hub arrangement with a cage freewheel which is installed in the clamping gap between a shaft and a hub, and with a rolling contact bearing on one side, in radial section;

[0036] FIG. 2 shows a first exemplary embodiment of a cage freewheel with a latched bearing disk in a radial bearing embodiment in a perspective view;

[0037] FIG. 3 shows the cage freewheel from FIG. 2 in a radial section;

[0038] FIG. 4 shows a second exemplary embodiment of a cage freewheel with a latched bearing disk in a radial/axial bearing embodiment in a perspective view;

[0039] FIG. 5 shows the cage freewheel from FIG. 4 in a radial section;

[0040] FIG. 6 shows a third exemplary embodiment of a cage freewheel with a latched bearing disk in a radial bearing embodiment in a perspective view;

[0041] FIG. 7 shows the cage freewheel from FIG. 6 in a radial section;

[0042] FIG. 8 shows a fourth exemplary embodiment of a cage freewheel with a latched bearing disk in a radial/axial bearing embodiment in a perspective view;

[0043] FIG. 9 shows the cage freewheel from FIG. 8 in a radial section;

[0044] FIG. 10 shows a first variant of a cage freewheel, which is fitted consecutively with sprags and bearing rollers, according to the second embodiment with a separated illustration of its components in a perspective view;

[0045] FIG. 11 shows the same components according to FIG. 10 in a radial section;

[0046] FIG. 12 shows the assembled cage ring according to FIGS. 10 and 11 in a shaft/hub connection;

[0047] FIG. 13 shows a second variant of a cage freewheel according to the second embodiment with a separated illustration of its components in a perspective view;

[0048] FIG. 14 shows the same components according to FIG. 13 in a radial section;

[0049] FIG. 15 shows the assembled cage ring according to FIGS. 13 and 14 in a shaft/hub connection;

[0050] FIG. 16 shows a third variant of a cage freewheel according to the second embodiment with a separated illustration of its components in a perspective view;

[0051] FIG. 17 shows the same components according to FIG. 16 in a radial section;

[0052] FIG. 18 shows the assembled cage ring according to FIGS. 16 and 17 in a shaft/hub connection;

[0053] FIG. 19 shows a fourth variant of a cage freewheel according to the second embodiment with a separated illustration of its components in a perspective view with a protrusion in segmented form on the cage ring;

[0054] FIG. 20 shows the same components according to FIG. 19 in a radial section;

[0055] FIG. 21 shows the assembled cage ring according to FIGS. 19 and 20 in a shaft/hub connection;

[0056] FIG. 22 shows a modification of the fourth variant with a segmented recess on the bearing disk;

[0057] FIG. 23 shows a further modification of the fourth variant, in which both the protrusion on the cage ring and the recess on the bearing disk are in segmented form, and

[0058] FIG. 24 shows an e-bike drive which is fitted with the cage freewheel according to FIGS. 10 to 23.

DETAILED DESCRIPTION

[0059] FIG. 1 shows a shaft and hub arrangement with a hub 2, a shaft 1 which is rotatable relative thereto with a cage freewheel 3 arranged in the clamping gap between shaft and hub (see FIGS. 5 and 6). The bearing disk 7 which is connected rotatable to the cage freewheel 3 but axially rigidly to the hub 2 is inserted into a corresponding receptacle of the hub 2 and is mounted in a sliding manner in relation to the shaft. Furthermore, in this example, the bearing disk permits an axial mounting of the cage freewheel in order therefore to secure the sprag cage against tilting, by locking in the axial direction. In this embodiment, the radial mounting is formed by the interaction of rolling contact bearing 4 and bearing disk 7. Despite the use of only one rolling contact bearing 4, mounting of the cage freewheel on both sides is therefore obtained via the rolling contact bearing 4 and the bearing disk 7.

[0060] FIG. 2 shows a cage freewheel which has a sprag cage 3 in the form of a flat cylindrical ring with a multiplicity of pockets which are consecutive in the circumferential direction. The cage freewheel is arranged between a shaft part and a hub part (not shown in this illustration). Sprags 5 are inserted into the pockets of the sprag cage 3. The sprags 5 can carry out a slight tilting movement in a manner known per se in their pockets and can thereby bring about a transmission of torque between the shaft part and the hub part in the blocking direction. In order to transmit high torques, the sprag cage 3 is fitted with as many sprags 5 as possible.

[0061] The sprags 5 of a sprag freewheel, which are frequently also referred to as clamping pieces, are, owing to the design, noncircular, i.e. have a long and a short direction of transverse extent. In their long transverse extent, the sprags are designed such that they clamp upon engagement in the annular gap formed by the outer surface of the shaft part and the inner running surface of the hub part.

[0062] So that the sprags 5 reliably engage, they are loaded or pretensioned in the engagement direction by an annular encircling spring ring 6, here in the form of a spiral spring placed in the circumferential direction about the row of sprags. For this purpose, the sprags have, on their outer contour surface, an encircling groove into which the spring ring 6 is placed.

[0063] The invention would also be able to be realized with other cage constructions, for example with clamping pieces spring-mounted individually or spring-mounted with an encircling sheet metal spring.

[0064] The sprag cage 3 has, on a side edge, an axially and radially projecting first latching element 3a which is hook-shaped in profile (see FIG. 3). The first latching element 3a corresponds in sections to a second latching element 7a on the bearing disk 7, said latching element 7a forming a recess or an undercut behind which the first latching element 3a can latch and grips therebehind from the outside inward. The two corresponding latching elements 3a, 7a can therefore latch together and form a latching connection between bearing disk 7 and the sprag cage 3, said latching connection intermeshing in a form-fitting manner.

[0065] The latching element 3a is in segmented form here, i.e. is interrupted in sections in the circumferential direction. The latching element 3a can thereby snap resiliently more easily into place in relation to the latching element 7a of the bearing disk 7.

[0066] The latching element 3a is designed here as a latching hook with a protrusion. The latter is pressed slightly inward, during the mounting of the bearing disk 7, until it latches behind the latching element 7a, which is likewise designed as a latching hook. This embodiment of a latching connection between sprag cage 3 and bearing disk 7 can be mounted in a simple manner, which is advantageous for a multiplicity of applications.

[0067] On its outer circumference, the bearing disk forms a sliding surface in relation to the hub part. The function as a radial bearing is thereby provided. Within the scope of the invention, a kinematic reversal of the bearing function, i.e. a sliding mounting in relation to the shaft part, would also be possible.

[0068] FIGS. 4 to 9 each show modified exemplary embodiments. To avoid repetitions, only the essential differences over the exemplary embodiment shown in FIG. 2 will be discussed below. Identical or corresponding elements are provided here with the same reference signs.

[0069] FIG. 4 shows a further exemplary embodiment of a cage freewheel. It is seen that the bearing disk has a region 7b, which extends in the radial direction, in the manner of a flange (see FIG. 5). The bearing disk 7 can be connected via said flange region 7b to the shaft part in an axially nondisplaceable, and preferably also rotationally fixed manner. In this exemplary embodiment, not only is mounting in the radial direction obtained, but so too is axial mounting, by means of the bearing disk 7.

[0070] The latching connection between sprag cage 3 and bearing disk 7 is form-fitting in the axial direction, but rotatable in the circumferential direction. This has the advantage that an effective fixing of the cage ring is produced and no further axial support is necessary.

[0071] FIG. 6 shows a further exemplary embodiment of a cage freewheel, in which the bearing disk 7 has the function of a radial bearing. It is essential in this embodiment that the bearing disk 7 has an axially and radially projecting, encircling latching element 3a on a side edge (see FIG. 6). Said latching element 7a corresponds in sections to a latching element 3a of the sprag cage 3 and grips behind said latching element from the inside outward. A latching connection between bearing disk 7 and the sprag cage 3, which latching connection intermeshes in a form-fitting manner, is therefore formed.

[0072] The latching element 3a is also in segmented form, i.e. interrupted in sections, on the sprag cage 3 in this case. By this means, the protrusion 7a can snap resiliently into place more easily in relation to the latching element 3a of the sprag cage 3.

[0073] The latching element 7a is designed here as a latching hook with a protrusion. During the mounting on the sprag cage 3, the latter presses its segmented latching element 3a slightly inward until it latches behind the latching element 3a, which is likewise designed as a latching hook. This embodiment of a latching connection between sprag cage 3 and bearing disk 7 can be mounted in a simple manner, which is advantageous for a multiplicity of applications. In this example, the bearing disk has an additional bevel which is intended to permit easier mounting.

[0074] FIG. 8 shows a further exemplary embodiment of a cage freewheel. It is seen that the bearing disk has a region 7b extending in the radial direction (see FIG. 9) which has an increased outside diameter in relation to the freewheel cage. Since said region of the bearing disk 7 that is of increased diameter is accommodated in a corresponding recess on the hub, the bearing disk 7 can be connected to the hub part in a nondisplaceable, and preferably also rotationally fixed manner. The bearing disk 7 here has the effect of axial mounting in addition to a sliding mounting in the radial direction. As can be seen in the exemplary embodiment in FIG. 6, the bearing disk 7 likewise has an additional bevel for easy mounting.

[0075] The latching element 3a of the sprag cage is again in segmented form here, i.e. interrupted in sections. The protrusion 3a can thereby snap resiliently into place more easily in relation to the latching element 3a of the bearing disk 7.

[0076] As can be seen in the exemplary embodiment in FIG. 6, the latching element 3a likewise has a latching hook with a protrusion. The latter, during the mounting of the bearing disk, is pressed slightly inward until it latches on the bearing disk 7 behind the latching element 7a, which is likewise designed as a latching hook, and grips behind the latter from the inside outward. This embodiment of a latching connection between sprag cage 3 and bearing disk 7 can be mounted in a simple manner, which is advantageous for a multiplicity of applications.

[0077] All of the exemplary embodiments are distinguished by minimal construction space since, by means of the form-fitting connection between cage ring and bearing disk and the design of the bearing disk 7 as a radial and optionally axial plain bearing, a second rolling contact bearing for the mounting of shaft and hub against each other can be dispensed with.

[0078] In the second embodiment according to FIG. 10, an inner shaft part 1 and an outer hub part 2 are seen, between which the cage freewheel is intended to be installed. The latter consists of the actual cage ring 3 in the form of a flat cylindrical ring with a multiplicity of windows 3a which are consecutive in the circumferential direction. Cylindrical bearing rollers 4 or sprags 5 can be inserted into the windows 3a. While the bearing rollers 4 take on the function of a roller bearing, the sprags 5 can carry out a slight tilting movement in a manner known per se in their windows and can thereby bring about a transmission of torque between shaft part 1 and hub part 2. In order to transmit high torques, the ring 3 is fitted with as many sprags 5 as possible, while, in the case of the bearing rollers 4, the minimum number of three bearing rollers is frequently sufficient.

[0079] So that the sprags 5 reliably engage, they are each loaded in the engagement direction by springs. In the exemplary embodiment, this is undertaken by an annular encircling spring ring 6 which has a spring tongue 6a in each case in the region of the sprags 5.

[0080] The sprags 5 of a sprag freewheel, which are frequently also referred to as clamping pieces, are caused by the design to be noncircular, i.e. have a long and a short direction of transverse extent. In their long transverse extent, the sprags are somewhat wider than the diameter of the bearing rollers 4, and therefore they are clamped upon engagement in the annular gap formed by the outer surface of the shaft part 1 and the inner running surface of the hub part 2. In their short direction of transverse extent, the sprags 5 are somewhat narrower than the diameter of the bearing rollers 4, and therefore, when spring-mounted in the engagement direction against the running surfaces of the annular gap, they run along said running surfaces.

[0081] It is now essential that the cage ring 3 has, on a side edge, an axially and radially projecting, encircling ring 3b (see FIG. 11). Said projecting ring 3b corresponds to a recess 7a in the form of an undercut in an axially adjacent bearing disk 7. Said bearing disk 7 is connected to the hub part 2 in an axially nondisplaceable, and preferably also rotationally fixed manner. On its inner circumference, it forms a sliding surface in relation to the shaft part 1.

[0082] FIG. 12 shows the cage ring in the installed state. It is seen in particular that the axial protrusion 3b of the cage ring that brings about the undercut is positioned virtually at the outer circumference of the cage ring in such a manner that the spring ring 6 runs inside the cage ring 3.

[0083] The form-fitting engagement between the axially and radially protruding protrusion 3b of the cage ring 3, which protrusion engages in a form-fitting manner in the axial direction, but movable in the circumferentially direction, in the recess 7a of the bearing disk 7, which is fixed in the axial direction, has the advantage that an effective fixing of the cage ring in both axial directions is produced, i.e. no further axial support is necessary on the other side of the cage ring.

[0084] FIGS. 13 to 15 show a second alternative of the cage ring. It essentially consists of the same parts, only the cage ring 13 and the recess 17a of the bearing disk 17 has a somewhat smaller diameter than in the first alternative. As a result, the cage ring 13 no longer runs on the outside, but rather on the inside of the spring ring 6, see FIG. 15.

[0085] Said inner position of the cage ring 13 is appropriate whenever the latter is intended to revolve with the shaft 1, rather than with the hub 2. In this case, the bearing disk 17 can be fixed to the shaft, where it is rotatable on its outer circumference relative to the hub 5.

[0086] In addition, in the second exemplary embodiment, the form-fitting engagement between the protrusion 13b and the recess 17a is not designed, as in the first exemplary embodiment, in the form of a dovetail, but rather in the form of a hook. For this purpose, the protrusion 13b has a conically running outer sliding surface, with which it slides along the inner circumference of the recess 17a upon latching into place on a corresponding sliding surface. The protrusion 13b which is designed in the manner of a latching hook is pressed slightly inward here until it latches into place behind the undercut formed by the recess 17a. This embodiment of a latching connection between cage ring 13 and bearing disk 17 is easier to mount and more difficult to dismount than the connection in the first exemplary embodiment, and this is advantageous for a multiplicity of applications.

[0087] FIGS. 16 to 18 and 19 to 21 describe a third and fourth alternative for the design of the cage ring. It differs from the previously described examples only in that it does not function with a single cage ring 3 or 13, but also with an additional supporting ring 23 or 33. Said supporting ring 23 or 33 is constructed similarly to the cage ring 3 or 13, i.e. in particular it contains the windows 23a or 33a necessary for receiving the bearing rollers and sprags. Said supporting ring assists the captive holding of the sprags 5 and bearing rollers 4 in the cage ring 3 or 13 and brings about a synchronization of the engagement movement of the sprags 5.

[0088] In the design according to FIGS. 16 to 18, the supporting ring 23 is arranged outside the cage ring 3, whereas the supporting ring 33 in the design according to FIGS. 19 to 21 is arranged inside the cage ring 13, see in particular FIGS. 18 and 21.

[0089] In both cases, the spring ring 6 is arranged between the cage ring 3 or 13 and the supporting ring 23 or 33.

[0090] The cage ring 3 or 13, the spring ring 6 and also the supporting ring 23 or 33 can be composed of metal or plastic.

[0091] It also lies within the scope of the invention to work not with closed rings, but rather with open, radially elastic rings.

[0092] As can be seen in FIG. 19, in the exemplary embodiment shown there the protrusion 3b on the cage ring 3 is designed as a segmented ring, i.e. ring which is interrupted in sections. The protrusion 3b can thereby snap resiliently into place more easily in relation to the recess 17a on the bearing disk 17.

[0093] In the variant shown in FIG. 22, instead of the protrusion 3b on the cage ring 3, the recess 17a on the bearing disk 17 or a projecting edge of the bearing disk 17 forming the undercut, is in segmented form, i.e. is interrupted in sections, while the protrusion 3b is designed as in FIG. 10 as a continuous ring. As explained, the recess 17a which is undercut in segmented form has advantages in terms of production when the bearing disk 17 is produced as a sintered part or injection molded part.

[0094] Finally, FIG. 23 illustrates a combined variant in which both the protrusion 3b on the cage ring 3 and the recess 17a on the bearing disk 17 are in segmented form.

[0095] All of the exemplary embodiments are distinguished by minimal construction space since, because of the form-fitting connection between cage ring and bearing disk, no further axial securing of the freewheel is required.

[0096] FIG. 24 shows an e-bike drive with the housing removed. It shows the drive shaft 1, frequently also referred to as bottom bracket shaft, which is connected rigidly to a sprocket 40 and a bottom bracket set 41 consisting of two end cranks with pedals.

[0097] A bottom bracket 42 via which the drive shaft is mounted in the frame of the bicycle is also seen.

[0098] In addition, the bottom bracket shaft 1 is drivable by an electric motor 45 via a helically toothed gearwheel 43 and a reduction gearing 44.

[0099] For this purpose, the gearwheel 43 is connected to the hub part 2 from FIGS. 10-12 and, with said hub part 2, surrounds the cage freewheel 3 described in FIGS. 10-12. The bearing disk 7 which is connected rotatably, but axially rigidly to the cage freewheel 3 is pressed into the corresponding receptacle in the hub part 2 and mounted in a sliding manner in relation to the bottom bracket shaft 1.