Bottom-bracket gear

Abstract

An arrangement for actuating a shift element for a bottom bracket gearbox (1) includes a shift ring (4) rotatably mounted in a housing (3) and assigned to a gearbox component. A shift pawl (5) for locking or releasing the shift ring (4) is assigned to the shift ring (4) for shifting a gear stage. A support region mechanically reinforces the housing (3) and is provided at least along a contact region (14) between an inner wall (8) of the housing (3) and an outer circumference of the shift ring (4). The contact region (14) is defined by reaction forces (16) acting when the shift ring (4) is locked.

Claims

1. An arrangement for actuating a shift element for a bottom bracket gearbox (1), comprising: a shift ring (4) rotatably mounted in a housing (3) and assigned to a gearbox component; a shift pawl (5) for locking or releasing the shift ring (4), the shift pawl (5) assigned to the shift ring (4) for shifting a gear stage, wherein a support region mechanically reinforces the housing (3), the support region provided at least along a contact region (14) between an inner wall (8) of the housing (3) and an outer circumference of the shift ring (4), the contact region (14) defined by reaction forces (16) acting when the shift ring (4) is locked.

2. The arrangement of claim 1, wherein the support region comprises a sleeve (18) fastened on the inner wall (8) of the housing (3), the sleeve (18) closed over a circumference of the sleeve (18).

3. The arrangement of claim 2, wherein the sleeve (18) is press-fit or thermally integrated into the housing (3).

4. The arrangement of claim 2, further comprising an acoustic damping region provided between the sleeve (18) and the inner wall (8) of the housing (3).

5. The arrangement of claim 4, wherein the acoustic damping region between the sleeve (18) and the inner wall (8) of the housing (3) comprises an elastomer vulcanized directly onto the sleeve (18).

6. The arrangement of claim 2, wherein a central axis of an inner contour of the sleeve (18) is situated with respect to the shift ring (4) coaxially or off-center by an average play between the shift ring (4) and the inner wall (8) of the housing (3).

7. The arrangement of claim 1, wherein the support region comprises a coating provided on the inner wall (8) of the housing (3), the coating increases a surface hardness of the inner wall (8) of the housing (3).

8. The arrangement of claim 1, wherein the support region comprises a ring segment-shaped push-in element (9).

9. The arrangement of claim 8, wherein the push-in element (9) is made of hardened spring steel.

10. The arrangement of claim 8, further comprising an acoustic damping region provided between the push-in element (9) and the inner wall (8) of the housing (3).

11. The arrangement of claim 10, wherein the acoustic damping region between the sleeve (18) and the inner wall (8) of the housing (3) comprises an elastomer vulcanized directly onto the push-in element (9).

12. The arrangement of claim 8, wherein a central axis of an inner contour of the sleeve (18) is situated with respect to the push-in element (9) coaxially or off-center by an average play between the shift ring (4) and the inner wall (8) of the housing (3).

13. The arrangement of claim 8, wherein dimensions of the push-in element (9) are selected such that at least the contact region (14) between outer toothing (6) of the shift ring (4) and the inner wall (8) of the housing (3) is covered, and the contact region (14) arises at an angle of ninety degrees away from a touch region (15) between the shift pawl (5) and the outer toothing (6) of the shift ring (5) when the shift pawl (5) is engaged.

14. The arrangement of claim 13, wherein end portions (10, 11) of the push-in element (9) are bent and are fastenable in corresponding retaining grooves (12, 13) in the inner wall (8) of the housing (3).

15. The arrangement of claim 14, wherein the retaining grooves (12, 13) and the end portions (10, 11) of the push-in element (9) are formed at a predetermined wedge angle () to an inner radius of the inner wall (8) of the housing (3).

16. The arrangement of claim 1, wherein: the shift element comprises a brake shift element; the shift ring (4) comprises a rotatably mounted brake ring; the shift pawl (5) comprises a brake pawl rotatably mounted via a pin (19); and the brake ring is lockable in one direction of rotation via the brake pawl.

17. A bottom bracket gearbox (1), comprising at least one of the arrangement of claim 1.

18. A bicycle or pedelec (2), comprising the bottom bracket gearbox (1) of claim 17.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Example aspects of the present invention are explained in greater detail in the following with reference to the drawings, wherein:

(2) FIG. 1 shows a schematic sectional view of an arrangement according to example aspects of the invention in a bottom bracket gearbox of a bicycle or pedelec;

(3) FIG. 2 shows a schematic sectional view of the arrangement with a push-in element as a support region on an inner wall of the housing;

(4) FIG. 3 shows a schematic part view according to FIG. 2 of the arrangement with an alternative example embodiment of a fastening of the push-in element on the housing; and

(5) FIG. 4 shows a schematic part view according to FIG. 2 of the arrangement with yet another alternative example embodiment of the fastening of the push-in element on the housing.

DETAILED DESCRIPTION

(6) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(7) In FIGS. 1 through 4 various views of an arrangement according to aspects of the invention in a bottom bracket gearbox 1 of a bicycle or pedelec 2 are shown as examples. It is apparent from the part view that the bottom bracket gearbox 1 in a planetary gear set design is arranged in a housing, or bottom bracket housing 3, of the bicycle or pedelec 2. The arrangement is used to actuate a brake shift element, which is shown by way of example, in the form of a shift element of the bottom bracket gearbox 1.

(8) The shift element, or brake shift element, has a brake ring 4, which is rotatably mounted in the housing 3, in the form of a shift ring. The brake ring 4 is locked in one direction of rotation or is released in both directions of rotation via a preferably single brake pawl 5 in the form of a shift pawl. The shift pawl 5, which is rotatably mounted in the housing 3 via a pin 19, is actuated by a shift drum 17 which is rotatably mounted in the housing 3. When the brake ring 4 is in the locked state in which the brake pawl 5 engages into an outer toothing 6 of the brake ring 4, a predetermined gear stage in the bottom bracket gearbox 1 is shifted. The brake ring 4 is radially guided and supported in a floating manner in the housing 3 over the outer circumference of the brake ring 4 and an inner diameter in the housing 3.

(9) As is apparent, in particular, from FIGS. 1 and 2, at least the lower region of the brake ring 4 is located directly in an oil sump 7 containing preferably low-viscosity oil, as a result of which the tribological contact region between the brake ring 4 and an inner wall 8 of the housing 3 is supplied with oil.

(10) In order to reduce the wear and the elastic, or plastic, flexibility at the inner wall 8 of the housing 3, which is preferably made of aluminum, a support region which mechanically reinforces the housing 3 is provided at least along a contact region 14 between the inner wall 8 of the housing 3 and an outer circumference, or the outer toothing 6, of the brake ring 4 due to a reaction force 16 acting when the brake ring 4 is locked. The contact region 14, or the support region, is indicated in FIG. 1 by a dashed line on the circumferential region of the brake ring 4.

(11) The indicated contact region 14 results due to the reaction forces 16 acting on the brake ring 4 and on the brake pawl 5 when the preferably single brake pawl 5 engages into the outer toothing 6 of the brake ring 4.

(12) The contact region 14 is located circumferentially approximately ninety degrees (90) away from the touch region 15 between the outer toothing 6 of the brake ring 4 and the engaged brake pawl 5. The reaction forces 16, which act on the brake pawl 5 and on the inner wall 8 of the housing 3, are indicated by arrows in FIG. 1. The reaction forces on the brake pawl 5 are transmitted via the pin 19 into the housing 3.

(13) Therefore, it is apparent that the reaction forces 16 on the brake ring 4 during locking contact are pressed by the brake pawl 5 against the housing 3 for force compensation and, in fact, opposite the touch region 15 between the brake ring 4 and the preferably single brake pawl 5. This means that the brake ring 4 is always supported at the identical, locally delimited location on the inner wall 8 of the housing 3. The support region on the housing 3 according to example aspects of the invention is provided precisely at this contact region 14.

(14) As the housing-side support region which increases the mechanical hardness of the housing 3, a closed sleeve 18 is provided on the housing wall 8 of the housing 3, the sleeve 18 being positioned with respect to the brake ring 4 coaxially or off-center by the average play between the brake ring 4 and the inner wall 8. The sleeve 18 is indicated in FIGS. 1 and 2. The prepositioning of the sleeve 18 off-center by the average play between the brake ring 4 and the inner wall 8 has the advantage that the brake ring 4, when rotationally fixed by the engaged brake pawl 5, is situated centrally with respect to the rotation axis of the bottom bracket gearbox 1.

(15) In FIGS. 2 through 4 a preferred example embodiment of the provided support region in the form of a ring segment-shaped push-in element 9 more or less in the form of a spring clamp or the like is shown as an example.

(16) The push-in element 9 extends symmetrically along the contact region 14 between the brake ring 4 and the inner wall 8 of the housing 3. In order to secure the push-in element 9, the end portions 10, 11 thereof are correspondingly bent in order to be secured directly in the housing 3 in assigned retaining grooves 12, 13. Preferably, the push-in element 9 is elastic, so that a preloading wedging of the push-in element 9 in the two retaining grooves 12, 13 can be achieved. The push-in element 9 therefore extends along the contact region 14 and covers the contact region 14 completely.

(17) According to example aspects the invention, the push-in element 9, or the spring clamp, when not installed, has a pre-curvature which is adapted specifically to the installed state, so that the spring clamp, when installed and elastically bent upwards, has the necessary curvature at the inner wall 8 of the housing 3 and an elastic springing with respect to the retaining grooves 12, 13 in order to be retained at the housing 3 in a friction-locking and/or interlocking manner depending on the shape of the groove.

(18) As is apparent, in particular, from FIG. 3, the retaining grooves 12, 13 are formed at a predetermined wedge angle to the inner radius of the inner wall 8 of the housing 3, so that the end portions 10, 11 of the push-in element 8, which are bent at the corresponding angle , are retained with an appropriate preload.

(19) FIG. 4 shows an example embodiment in which the end portions 10, 11 are bent twice and the retaining grooves 12, 13 are correspondingly adapted to the twice-bent end portions 10, 11, such that, in addition to the friction-locking fastening, an interlocking fastening of the end portions 10, 11 of the push-in element 9 in the retaining grooves 12, 13 is also achieved.

(20) Regardless of the particular example embodiment of the retaining grooves 12, 13, the retaining grooves 12, 13 may be introduced into the housing 3 in the casting process. It is also conceivable that the retaining grooves 12, 13 are produced by machining the housing 3. The push-in element 9 is installed either by being inserted axially into the retaining grooves 12, 13 of the housing 3 or by being snapped in radially from the outside. The push-in element 9 is secured against migrating laterally outward via a cover, or the like, which has been screwed onto the housing 3.

(21) As an alternative or in addition to the push-in element 9 in the form of a support region, the sleeve 18, which is shown, or a bore can be provided directly in the housing 3, which is made of an aluminum alloy, and the inner surface of the housing bore can be in the form of a coating which has been hardened on the surface or provided via hard anodizing.

(22) Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE CHARACTERS

(23) 1 bottom bracket gearbox 2 bicycle or pedelec 3 housing, or bottom bracket housing 4 shift ring, or brake ring 5 shift pawl, or brake pawl 6 outer toothing 7 oil sump 8 inner wall of the housing 9 push-in element 10 end portion of the push-in element 11 end portion of the push-in element 12 retaining groove in the housing 13 retaining groove in the housing 14 contact region, or support region, between brake ring and housing 15 touch region between outer toothing and brake pawl 16 reaction force 17 shift drum 18 sleeve 19 pin wedge angle of the retaining groove