Bicycle gear shifting device

Abstract

A bicycle gear shifting device (10) comprises a first body associated with a bicycle frame, a second body (36) connected to the first body and movable with respect to the first body, a rocker arm (20) rotatably connected to the second body at a rotation axis (X), a shaft (23) coaxially extending with the rotation axis (X) and fixedly associated with the rocker arm. A one-way rotation device (80) is arranged between the shaft and the second body to allow the shaft to rotate with respect to the second body about the rotation axis (X) only in a first rotation direction. A first elastic element (40) is associated with both the second body and the rocker arm to urge the rocker arm to rotate about the rotation axis (X) in the first rotation direction. A damping device (50) is arranged between the shaft and the one-way rotation device to generate a friction force when the rocker arm moves about the rotation axis (X) in a second rotation direction opposite to the first rotation direction. The damping device comprises a friction surface (52) axially extending along a direction parallel to the rotation axis (X) and in contact with the one-way rotation device.

Description

TECHNICAL FIELD

[0001] The present invention relates to a bicycle shifting device, preferably to a shifting device for a racing bicycle. BACKGROUND

[0002] In the present description, the shifting device specifically referred to is a rear shifting device. This shifting device causes the chain to move between different sprocket wheels of a sprocket wheel assembly associated with the rear wheel of the bicycle.

[0003] In addition to the function of correctly moving the chain, the rear shifting device also performs the function of keeping the chain correctly tensioned when engaged by any different sprocket wheel and during shifting, to prevent the chain from falling.

[0004] The rear shifting device generally comprises a first body associated with the frame of the bicycle and a second body supporting a rocker arm. The latter comprises an inner plate, an outer plate and a pair of gears arranged between the inner plate and the outer plate and configured to engage the chain.

[0005] In the present description, the terms "inner plate" and "outer plate" respectively refer to: the plate of the rocker arm which, when the rocker arm is installed on the bicycle, faces the wheel of the bicycle; and the plate of the rocker arm which, in the aforementioned installation conditions, is arranged more externally with respect to the wheel of the bicycle.

[0006] The second body is connected to the first body by a pair of articulated connecting rods, to form an articulated quadrilateral actuation linkage. This linkage is mechanically actuated by a sheathed cable or electrically actuated by an electric motor.

[0007] Upon actuation of the aforementioned linkage, the second body moves with respect to the first body, thereby moving the rocker arm to the sprocket wheel selected by the rider and engaging the chain on such sprocket wheel.

[0008] The rocker arm is rotatably connected to the second body at a predetermined rotation axis.

[0009] In the present description and in the appended claims, the term "axial" or "axially" is used to indicate a direction which coincides or is parallel to the aforementioned rotation axis, the term "circumferential" or "circumferentially" is used to indicate a direction of rotation around the aforementioned rotation axis, while the term "radial" or "radially" is used to indicate a direction which passes through and is perpendicular to the aforementioned rotation axis.

[0010] A resilient element, typically a torsion spring, urges the rocker arm to rotate around such rotation axis in a direction hereinafter indicated as "chain tensioning direction". When the outer plate of the rocker arm installed on the bicycle is viewed from the front, the chain tensioning direction corresponds to the direction of rotation of the rocker arm around the aforementioned rotation axis in a clockwise direction.

[0011] During the shifting operation and / or during travel, especially in the case of irregular road surfaces, the rocker arm oscillates about the aforementioned rotation axis. In this oscillation forward, the rocker arm moves in a rotation direction opposite to the chain tensioning direction, causing the chain to momentarily loosen and thus causing the risk of chain drop.

[0012] To dampen the oscillation of the rocker arm, it is known to provide a one-way damping device between the rocker arm and the second body. This damping device is configured to exert a friction force on the rocker arm when the latter moves about the rotation axis in a rotation direction opposite to the chain tensioning direction, and to allow the rocker arm to rotate freely in the chain tensioning direction.

[0013] US 9475547 with reference to which Figure 7 An embodiment of a bicycle rear shifting device is described, comprising a one-way rotation device constituted by a one-way roller bearing 246 and a damping device 238 comprising a friction element 250 having an annular shape and operatively arranged between a shaft 240, fixedly connected to the rocker arm, and the one-way roller bearing 246. The friction element 250 comprises a frustoconical or wedge-shaped friction surface which interacts with a sleeve 248, fixedly connected to the inner ring of the one-way roller bearing 246. An adjustment element 277 acts on the friction element 250, said element 277 being screwed onto the shaft 240 and exerting an axial preloading force on the friction element 250.

[0014] The Applicant has observed that, due to the frustoconical or wedge-shaped friction surface of the friction element 250, this element exerts a thrust on the sleeve 248 having both a radial component and an axial component.

[0015] The Applicant has identified a series of drawbacks of the aforementioned bicycle shifting device.

[0016] First of all, due to the aforementioned axial component, only a fraction of the axial preloading force exerted by the adjustment element 277 on the friction element 250 is converted into a radial thrust acting on the inner ring of the one-way roller bearing 246. Furthermore, since the aforementioned radial thrust is generated only by the axial preloading force generated by the adjustment element 277, it is necessary to act on such adjustment element 277 to compensate for possible reductions in the amount of radial thrust due to wear of the components or dimensional tolerances of the parts. Moreover, it is necessary to block the axial movement of the sleeve 248 to generate a sufficient radial thrust on the inner ring of the one-way roller bearing 246. Finally, it is difficult to prevent a fraction of the friction force from also acting on the interface between the shaft 240 and the element 250, and this makes the performance of the system inefficient and unstable.

[0017] According to the Applicant, the aforementioned drawbacks, if not properly taken into account, can lead over time to the shifting device no longer having optimal operating efficiency and performance stability in response to stresses which tend to move the rocker arm in a rotation direction opposite to the chain tensioning direction. SUMMARY

[0018] The problem underlying the present application is to make a bicycle shifting device which comprises damping means which ensure greater efficiency and performance stability over time with respect to the devices described with reference to the prior art.

[0019] The present application therefore relates to a bicycle shifting device comprising: - a first body configured to be associated with a bicycle frame; - a second body connected to said first body and movable with respect to said first body; - a rocker arm rotatably connected to said second body at a rotation axis; - a shaft extending coaxially to said rotation axis and fixedly associated with said rocker arm; - one-way rotation means operatively arranged between said shaft and said second body and configured to allow the rotation of said shaft about said rotation axis with respect to the second body only in a first rotation direction; - a first elastic element associated with the second body and the rocker arm and configured to push said rocker arm to rotate about said rotation axis in said first rotation direction; - damping means operatively arranged between said shaft and said one-way rotation means and configured to generate a friction force when said rocker arm moves about said rotation axis in a second rotation direction opposite to said first rotation direction; characterized in that said damping means comprise at least one friction surface which extends axially along a direction substantially parallel to the rotation axis and is in contact with said one-way rotation means.

[0020] Providing a friction surface which extends axially along a direction substantially parallel to the rotation axis of the rocker arm causes the generation of a friction force between the damping means and the one-way rotation means which has only a circumferential component and causes the damping means to exert on the one-way rotation means a thrust force which has only a radial component, i.e. without an undesirable axial component.

[0021] The operating efficiency of the shifting device is therefore improved since, once a certain radial preload has been exerted on the one-way rotation means by the damping means, the entire preload force is converted into a radial thrust force acting on the one-way rotation means.

[0022] During the service life of the shifting device, possible dimensional deviations from the design dimensions due to wear of the shifting device components or their dimensional tolerances can be automatically compensated by the damping device, which adjusts itself by suitably varying the radial thrust exerted on the one-way rotation device. Advantageously, therefore, the performance of the shifting device has stability over time. It is therefore easier to provide and accurately control the behavior of the shifting device in response to stresses that tend to move the rocker arm in a rotation direction opposite to the chain tensioning direction.

[0023] In the following, preferred and / or optional features of the bicycle shifting device according to the present application are described. These features can be provided individually or in combination with each other, unless explicitly stated otherwise.

[0024] Preferably, the damping device comprises at least two friction surfaces. For example, there can be two, three or four friction surfaces.

[0025] In the case of two friction surfaces, these are preferably arranged on opposite sides with respect to the rotation axis, i.e. at about 180° from each other.

[0026] In the case of three surfaces, these are preferably arranged at about 120° from each other.

[0027] In the case of four friction surfaces, these are preferably arranged at about 90° from each other.

[0028] In all the above cases, the damping device acts on the one-way rotation device in a balanced manner around the rotation axis.

[0029] Preferably, the aforementioned friction surfaces are defined on respective jaws.

[0030] Preferably, each of the at least two friction surfaces extends circumferentially around the rotation axis for an arc of circumference centered on the rotation axis and having a central angle less than 180°.

[0031] Preferably, the central angle is comprised between 80° and 160°, more preferably between 110° and 140°, even more preferably, the central angle is equal to about 125°.

[0032] Preferably, the damping device comprises at least one thrust member configured to push the at least one friction surface against the one-way rotation device with a predetermined load.

[0033] Such a thrust member determines a preloading force, which in turn determines the value of the radial thrust exerted by the damping device on the one-way rotation device, thereby determining the degree of damping action.

[0034] Moreover, the thrust member is able to restore possible dimensional deviations from the design size due to wear or dimensional tolerances, thus contributing to the automatic compensation described above.

[0035] The provision of the thrust member described above allows to define the desired thrust in the assembly step of the shifting device, making any post-sale maintenance intervention aimed at adjusting the thrust exerted by the damping device on the one-way rotation device superfluous and / or unnecessary. Such intervention would indeed be cumbersome, as it would require the complete disassembly of the rocker arm, of the first elastic element and of the damping device.

[0036] In a first embodiment of the application, and in the case where such a shifting device comprises two friction surfaces arranged on opposite sides with respect to the rotation axis, said at least one thrust member comprises a second elastic element housed in a through hole formed in said shaft, the through hole being along a direction perpendicular to said rotation axis.

[0037] Preferably, said second elastic element is arranged in a radially internal position with respect to said two friction surfaces.

[0038] The second elastic element crosses the shaft and, at its two ends, pushes the two opposite friction surfaces against the one-way rotation device with the same force. The radial thrust exerted on the friction surfaces is therefore counteracted by the opposite friction surfaces through the second elastic element.

[0039] Preferably, the second elastic element is a helical spring.

[0040] In this case, therefore, the radial thrust is only a function of the elastic constant of the helical spring. In the assembly step of the shifting device, it will be possible to select among the various possible available springs a spring having an elastic constant suitable for exerting the desired radial thrust on the one-way rotation device.

[0041] Preferably, the two friction surfaces are formed on respective jaws provided with respective seats configured to house respective ends of the second elastic element.

[0042] Such seats contribute to prevent unwanted axial movements of the second elastic element, thus ensuring that the entire preload force exerted by the thrust member is converted into radial thrust.

[0043] In a second embodiment of the application, and independently of the number of friction surfaces provided, said at least one thrust member comprises at least one coil spring or at least one helical spring arranged between said shaft and said at least one friction surface.

[0044] Moreover, in this case the radial thrust is only a function of the spring's elastic constant. However, in this case the radial thrust exerted on the friction surface is counteracted by the shaft.

[0045] In the assembly step of the shifting device, in this case it will also be possible to select among the various possible available springs a spring having an elastic constant suitable for exerting on the one-way rotation device the desired radial thrust.

[0046] In some embodiments of the shifting device of the present application, the damping device comprises an adjustment device configured to adjust said predetermined load.

[0047] In a first embodiment of said adjustment device, the adjustment device comprises at least one first spacing element having a predetermined thickness.

[0048] Such adjustment device can be arranged between said at least one thrust member and said at least one friction surface or between said at least one thrust member and said shaft, or both between said at least one thrust member and said at least one friction surface and between said at least one thrust member and said shaft.

[0049] For example, the first spacing element can be a washer having a calibrated thickness. In the assembly step of the shifting device, it will be possible to select among the various possible available spacing elements having different thicknesses a spacing element having a thickness suitable for exerting on the one-way rotation device the desired radial thrust.

[0050] In another embodiment of said adjustment device, the adjustment device comprises a preloading device comprising a thrust pin movable within a first hole extending in said shaft along a first direction perpendicular to the rotation axis and exerting a thrust on at least one thrust plate movable within a second hole connected to said first hole and extending in said shaft along a second direction perpendicular to the rotation axis.

[0051] Preferably, the second hole is arranged in a radially internal position with respect to said at least one thrust member.

[0052] The preloading device makes it possible to adjust the preloading force exerted by the damping device on the one-way rotation device as a function of needs.

[0053] Preferably, the first hole and the second hole are substantially perpendicular.

[0054] More preferably, said thrust pin comprises a substantially wedge-shaped end.

[0055] Even more preferably, said at least one thrust plate comprises a substantially wedge-shaped end portion which abuts against a substantially wedge-shaped end portion of said thrust pin.

[0056] Preferably, the aforesaid wedge-shaped surfaces are inclined at about 45° with respect to the rotation axis, but they can also be inclined at different angles, including between 15° and 75°. In this way, the movement of the pin along its axis is converted into a radial movement of the thrust plate, and the choice of the angle of inclination provides for greater or lesser sensitivity of the adjustment.

[0057] Preferably, the axis of the pin is substantially perpendicular to the rotation axis.

[0058] In a further embodiment of said adjustment device, the adjustment device comprises a second spacing element having a predetermined thickness, which is housed in a through hole formed in said shaft in a direction perpendicular to said rotation axis and is arranged in a radially internal position with respect to said at least two friction surfaces.

[0059] Preferably, said at least one thrust member comprises a plurality of disc springs housed in a bushing housed in said through hole and arranged on opposite sides with respect to said second spacing element.

[0060] In this case, the radial thrust exerted on the friction surfaces is counteracted by the second spacing element and by the disc springs by the opposite friction surfaces. The radial thrust exerted by the damping device on the one-way rotation device is therefore a function of the elastic constant of the disc springs and of the thickness of the second spacing element. In the assembly step of the gear shift device, it is therefore necessary to appropriately select among the various springs and among the various spacing elements those springs and spacing elements having a certain elastic constant and a certain thickness, respectively, suitable for exerting the desired radial thrust on the one-way rotation device.

[0061] In a preferred embodiment of the application, said shaft comprises an enlargement in a radially internal position with respect to said damping device.

[0062] Preferably, said enlargement comprises at least one flat surface.

[0063] Preferably, said enlargement comprises a flat surface facing the respective friction surface.

[0064] Preferably, said adjustment device is arranged at said enlargement. The through holes configured to house the aforesaid coil springs and / or disc springs and / or second spacing elements are therefore formed on said enlargement and open onto the two opposite flat surfaces of such enlargement.

[0065] In the case where the enlargement of the shaft does not have the aforesaid through holes, the flat portion defines an abutment surface for the end portion of the thrust member opposite to the end portion exerting the thrust on the friction surface.

[0066] In a preferred embodiment of the application, the one-way rotation device comprises a radial bearing having an outer ring fixedly associated with said second body and an inner ring operatively associated with said at least one friction surface.

[0067] Preferably, the radial bearing is a roller bearing, so as to contain the radial dimension of the bearing.

[0068] In a first preferred embodiment of the application, the damping device is arranged at least partially in a radially internal position with respect to said inner ring. In this case, the shifting device has a small axial dimension.

[0069] Preferably, the damping device is arranged completely in a radially internal position with respect to said inner ring.

[0070] In a second preferred embodiment of the application, the damping device is arranged at least partially in a radially internal position with respect to said annular element, fixedly associated with said inner ring and axially adjacent.

[0071] Preferably, in this case, the shifting device comprises a self-lubricating bushing arranged between said shaft and said inner ring.

[0072] This bushing ensures the precise centring of the shaft with respect to the one-way rotation device and, consequently, with respect to the damping device, without generating undesired additional friction (i.e. further friction with respect to the friction force generated by the friction surface) between the damping device and the radial bearing.

[0073] Preferably, the annular element has a diameter greater than the diameter of the inner ring of the radial bearing.

[0074] Preferably, the annular element is arranged axially between the inner ring of the radial bearing and the rocker arm.

[0075] In a preferred embodiment of the shifting device of the application, the shifting device comprises a pair of axially abutment surfaces arranged on opposite sides with respect to said damping device and configured to prevent the axial movement of said damping device, in particular of the friction surface.

[0076] Preferably, a first surface of said axially abutment surfaces is made in a single piece with the shaft.

[0077] Preferably, the first axially abutment surface is axially adjacent to the enlarged portion of the shaft, more preferably, the first axially abutment surface is arranged between the enlarged portion of the shaft and the rocker arm.

[0078] In some embodiments, the first axially abutment surface is substantially formed at the middle of the shaft.

[0079] The other of the aforesaid axial abutment surfaces can be defined by the interface surface between the inner ring of the radial bearing and the aforesaid annular element, when provided, or, when the aforesaid annular element is not provided and the damping device is housed within the inner ring of the radial bearing, by a flange associated with the following end of the shaft, opposite the end associated with the rocker arm.

[0080] Preferably, said first elastic element comprises a helical return spring.

[0081] The damping device can be arranged at least partially in a radially internal position with respect to said return spring. This arrangement can allow the axial dimension of the shifting device to be kept small.

[0082] Preferably, the damping device is arranged completely in a radially internal position with respect to said return spring.

[0083] The damping device can also be arranged at least partially in an axially adjacent position with respect to said return spring. This is the case, for example, when the damping device is arranged at least partially in a radially internal position with respect to the inner ring of the radial bearing, which is arranged at least partially in an axially adjacent position with respect to the return spring. BRIEF DESCRIPTION OF DRAWINGS

[0084] Further features and advantages of the present application will become apparent from the detailed description of preferred embodiments of the present application, which is made with reference to the accompanying drawings, given by way of example only and in which:

[0085] - Figure 1 is a perspective view of a first preferred embodiment of a bicycle shifting device according to the present application;

[0086] - Figure 2 is an exploded perspective view of a portion of the bicycle shifting device of Figure 1 ;

[0087] - Figure 3 is a longitudinal sectional view of a portion of the bicycle shifting device of Figure 2 ;

[0088] - Figure 4 is an exploded perspective view of a portion of a second preferred embodiment of a bicycle shifting device according to the present application;

[0089] - Figure 5 is a longitudinal sectional view of a portion of the bicycle shifting device of Figure 4 ;

[0090] - Figure 6is a longitudinal sectional view of some components which are part of a third preferred embodiment of a bicycle shifting device according to the present application;

[0091] - Figure 7 is a cross-sectional view of the components shown in Figure 6 taken in the VII-VII plane according to Figure 6 ;

[0092] - Figure 8 is a longitudinal sectional view of some components which are part of a fourth preferred embodiment of a bicycle shifting device according to the present application;

[0093] - Figure 9 is a cross-sectional view of the components shown in Figure 8 taken in the IX-IX plane according to Figure 8 ;

[0094] - Figure 10 is a longitudinal sectional view of some components which are part of a fifth preferred embodiment of a bicycle shifting device according to the present application;

[0095] - Figure 11 is an exploded perspective view of some components which are part of a bicycle shifting device according to Figure 10 ;

[0096] - Figure 12 is a longitudinal sectional view of some components which are part of a sixth preferred embodiment of a bicycle shifting device according to the present application;

[0097] - Figure 13 is an exploded perspective view of some components which are part of a bicycle shifting device according to Figure 12 ; DETAILED DESCRIPTION

[0098] In the drawings, reference number 10 indicates a bicycle shifting device according to a first preferred embodiment of the present application. Figures 1 to 3

[0099] In particular, the shifting device is a rear shifting device, i.e. a shifting device configured to be mounted on a bicycle frame (not shown) so that a chain (not shown) moves between different sprockets (not shown) of a sprocket assembly associated with a rear wheel of the bicycle.

[0100] The movement of the chain is actuated by the movement of the rocker arm 20. This movement is the result of the movement of the actuation linkage 30.

[0101] ​The shifting device 10 can be mechanically actuated (via a sheathed cable) or motorized (via an electric motor). The accompanying drawings, by way of a non-limiting example, illustrate a motorized shifting device in which movement of the rocker arm 20 occurs via a motor component 32, which is appropriately driven, typically electrically. Once the motor component 32 is driven, the actuating linkage 30 deforms and the rocker arm 20 moves.

[0102] The actuating linkage 30 is a hinged quadrilateral linkage, preferably a hinged parallelogram linkage. This linkage includes a first body 34, a second body 36, and a pair of hinged links 38. The first body is configured to be associated with the bicycle frame, the second body is configured to support the rocker arm 20, and the pair of hinged links connects the first body 34 and the second body 36. Referring to the relative position of the links 38 with respect to the bicycle frame, these links are also referred to as the "inner link" and the "outer link," respectively.

[0103] The rocker arm 20 is associated with the second body 36.

[0104] In the example shown here, the motor component 32 is housed within the first body 34 and drives the actuating linkage 30 to deform, lengthening or shortening the diagonal of the hinged quadrilateral. Specifically, this lengthening of the diagonal is used to perform upward shifting (towards a sprocket with a larger diameter), while the shortening of the diagonal is used to perform downward shifting (towards a sprocket with a smaller diameter).

[0105] When the actuating linkage 30 deforms, the second body 36 moves relative to the first body 34, the rocker arm 20 moves to the sprocket selected by the rider, and the chain is engaged by such sprocket.

[0106] The rocker arm 20 includes a pair of opposing plates 22, namely an inner plate and an outer plate, and a pair of gears 24a and 24b arranged between the inner plate 22 and the outer plate 22 and configured as a meshing chain. The outer plate 22 is adjacent to the second body 36.

[0107] The rocker arm 20 is rotatably connected to the second body 36 at a predetermined axis of rotation X, which is substantially perpendicular to the planar extension of the outer plate 22.

[0108] Shaft 23 is fixedly associated with the outer plate 22 of rocker arm 20. Such shaft 23 extends coaxially with the axis of rotation X via second body 36 and is configured to rotate about the axis of rotation X relative to second body 36 as a unit with rocker arm 20.

[0109] like Figure 2 and Figure 3 As shown, the fixing element 62 is connected to the outer plate 22 of the rocker arm 20. The fixing element 62 can be co-molded, glued, interference-fitted, or otherwise conventionally attached to the outer plate 22.

[0110] The fixing element 62 has a hole 63 which extends coaxially with the rotation axis X.

[0111] The end 23a of the shaft 23 passes through a through hole 22a formed in the outer plate 22 and is housed in the hole 63 of the fixing element 62, for example by interference or by screwing.

[0112] The opposite end 23b of the shaft 23 passes through a through hole 36a formed in the second body 36 and is coupled with an annular nut 37a. In Figures 1 to 3 In the non-limiting example shown, the through hole 36a is formed in an insert 36c which is co-moulded with the second body 36.

[0113] A support bearing 37 is arranged between the end 23b and a corresponding end of the second body 36. This support bearing 37 is housed in a seat 36b of the second body 36 which is coaxial with the rotation axis X. In Figures 1 to 3 In the non-limiting example shown, the seat 36b is formed in an end of the insert 36c.

[0114] The annular nut 37a prevents the support bearing 37 from coming out of the seat 36b and axially locks the shaft 23. This annular nut can be replaced by a Seeger ring.

[0115] The shifting device 10 also comprises a cover 70 which is removably associated with the second body 36 by snap coupling, or screw coupling, or interference coupling, or by means of screws, gluing or other means which are conventional per se. This cover 70 is arranged above the end 23b of the shaft 23, thereby also covering the support bearing 37.

[0116] In Figures 1 to 3 The elastic element which in the embodiment shown is a helical return spring 40 is associated with the second body 36 and with the rocker arm 20 to push the rocker arm 20 to rotate about the rotation axis X in a chain tensioning direction. In Figure 1 corresponding to a front view of the outer plate 22 of the rocker arm 20 mounted on a bicycle, this chain tensioning direction corresponds to the direction of rotation of the rocker arm 20 in the clockwise direction.

[0117] As Figure 3 shown, the helical return spring 40 is housed in a seat 42 which is formed in the second body 36.

[0118] A one-way rotation device 80 is operatively arranged between the shaft 23 and the second body 36. This one-way rotation device 80 is configured to allow the shaft 23 to rotate with respect to the second body 36 only in the chain tensioning direction.

[0119] Specifically, the unidirectional rotating device 80 includes a radial bearing having an outer ring 82 and an inner ring 84, the outer ring being fixedly associated with the second body 36. Figures 1 to 3 In the unrestricted example shown, the outer ring 82 is fixedly associated with the insert 36c.

[0120] The radial bearing is preferably a roller bearing.

[0121] A damping device 50 is operatively arranged between the shaft 23 and the unidirectional rotating device 80. This damping device 50 is configured such that when the rocker arm 20 rotates about the axis of rotation X in a direction opposite to the chain tension direction (i.e., referring to…),… Figure 1 When moving in the counterclockwise rotation direction, a frictional force is applied to the rocker arm 20.

[0122] like Figure 2 As shown, the damping device 50 includes two friction surfaces 52 that extend axially in a direction substantially parallel to the axis of rotation X.

[0123] The two friction surfaces 52 are arranged on opposite sides relative to the axis of rotation X, i.e., at approximately 180° to each other.

[0124] Each friction surface 52 is defined on the gripper 54.

[0125] In the example shown here, the gripper 54 has the shape of a cylindrical cap, which has cylindrical surfaces defining a friction surface 52 and a flat base surface 53. Specifically, the gripper 54 is formed in any cross-section (i.e., in a section taken according to a plane perpendicular to the axis of rotation X) into a segment similar to the following: the segment is defined by an outer circumferential arc and a chord of the outer circumference. The friction surface 52 is defined at the aforementioned outer circumferential arc, while the flat surface 53 is defined at the aforementioned outer circumferential chord.

[0126] The friction surface 52 extends circumferentially around the rotation axis X in a certain outer arc, which has a center on the rotation axis X and has a central angle of less than 180°. The central angle is preferably between 80° and 160°, more preferably between 110° and 140°, and even more preferably equal to about 125°.

[0127] The friction surface 52 acts directly or indirectly on the inner ring 84 of the radial bearing to prevent the inner ring from rotating.

[0128] The friction surface 52 is preferably provided with knurling and / or ribs to deliver possible lubricant for internal components and to prevent such lubricant from flowing to the outermost part of the surface 52, which, on the other hand, must generate friction.

[0129] exist Figures 1 to 3In the example shown, the inner ring 84 of the radial bearing is operatively associated with the friction surface 52 by means of an annular element 86 fixedly associated with the inner ring 84. The annular element 86 thus forms part of the one-way rotation device 80.

[0130] The annular element 86 is axially adjacent to the inner ring 84. In particular, it is arranged axially between the inner ring 84 of the radial bearing and the rocker arm 20.

[0131] The annular element 86 has a diameter greater than that of the inner ring 84. The inner ring 84 is thus connected to the annular element 86 by means of a flat annular interface surface 85 extending perpendicularly to the rotation axis X. This annular interface surface 85 defines, as described below, an axial abutment surface for the jaw 54.

[0132] A washer 88 is arranged between the annular interface surface 85 of the radial bearing and the outer ring 82 and acts as a spacer.

[0133] In this embodiment of the shifting device 10 of the application, the damping device 50 is arranged in a radially internal position with respect to the annular element 86.

[0134] The shaft 23 comprises a cylindrical portion 23c adjacent to the end portion 23b and arranged in a radially internal position with respect to the inner ring 84, and an enlarged portion 23d adjacent to the end portion 23a and arranged in a radially internal position with respect to the annular element 86.

[0135] A self-lubricating bushing 83 is preferably arranged between the cylindrical portion 23c of the shaft 23 and the inner ring 84. This self-lubricating bushing 83 supports the shaft 23 to ensure a predetermined radial clearance with respect to the inner ring 84. This radial clearance is suitable to avoid galling of the shaft 23, which is subjected to torsional-flexural loads induced by the rocker arm 20.

[0136] In fact, the self-lubricating bushing 83 performs the same function as the support bearing 37. There are thus embodiments that provide only the self-lubricating bushing 83 without the support bearing 37, embodiments that provide only the support bearing 37 without the self-lubricating bushing 83, and embodiments that provide both the self-lubricating bushing 83 and the support bearing 37 (similar to the one shown in Figures 1 to 3 ).

[0137] The enlarged portion 23d comprises two opposite flat surfaces 23e, each of which faces a respective jaw 54.

[0138] The damping device 50 comprises a thrust member 56 arranged between the shaft 23 and the respective jaw 54 and configured to push the jaw 54 against a radially internal cylindrical surface 86a of the annular element 86 with a predetermined load (pre-load).

[0139] The thrust member 56 comprises a disc spring or a coil spring. In the non-limiting example illustrated, a plurality of disc springs 57 is provided at each jaw 54. Figure 2

[0140] In the non-limiting example illustrated, the damping device 50 further comprises an adjustment device 58 configured to adjust the aforesaid predetermined load. In a variant not illustrated, the adjustment device 58 can be omitted. Figures 1 to 3

[0141] The adjustment device 58 comprises a spacing element 59 having a predetermined thickness, for example a washer having a calibrated thickness. In particular, in the non-limiting example illustrated, two washers are provided at each thrust member 56. Figures 1 to 3

[0142] Each of the two opposite flat surfaces 23e of the enlargement 23d defines an abutment surface for the end of the thrust member 56 opposite to the end exerting the thrust on the jaw 54.

[0143] In the non-limiting example illustrated, two washers are arranged between the thrust member 56 and the jaw 54, in particular between the plurality of disc springs 57 and the flat surface 53 of the jaw 54. Such washers can also or only be arranged between the flat surface 23e of the shaft 23 and the end of the thrust member 56 adjacent to it. Figure 2 A substantially cylindrical seat 53a is formed on the flat surface 53 of each jaw 54, said seat being configured to house a washer and preferably at least part of a disc spring 57, so as to prevent unwanted axial movements of the disc spring.

[0144] The axial abutment surface 51a is made in a single piece with the shaft 23 in a position axially adjacent to the enlargement 23d and is arranged between the enlargement 23d and the rocker arm 20. As

[0145] Figure 2 As illustrated, the axial abutment surface 51a is arranged between the enlargement 23d and the end 23a of the shaft 23 and cooperates with the annular interface surface 85 to keep the jaw 54 in a predetermined axial position. Figure 3 The jaw 54 has two opposite axial abutment surfaces 54a configured to be axially contained by the axial abutment surfaces 51a, 85, with suitable clearances that prevent the sliding of the axial abutment surfaces 54a.

[0146] In the non-limiting example illustrated, the damping device 50 further comprises an adjustment device 58 configured to adjust the aforesaid predetermined load. In a variant not illustrated, the adjustment device 58 can be omitted.

[0147] Figures 1 to 3 ​​​​​In the non-limiting example shown, the damping device 50 and the annular element 86 are arranged entirely in a radially internal position with respect to the helical return spring 40.

[0148] Figure 4 and Figure 5 A second preferred embodiment of the bicycle shifting device 10 according to the present application is shown.

[0149] Figure 4 and Figure 5 The components of the bicycle shifting device 10 of Figures 1 to 3 The components of the bicycle shifting device 10 of

[0150] Figure 4 and Figure 5 The bicycle shifting device 10 of Figures 1 to 3 The bicycle shifting device 10 of Figure 2 The washer shown in Figure 4 and Figure 5 The embodiment of Figure 2 The embodiment of

[0151] The thrust pin 159 is movable inside a hole 23f which extends in the shaft 23 at the enlarged portion 23d of the shaft.

[0152] The hole 23f extends along a direction perpendicular to the rotation axis X and opens into a surface 23g of the enlarged portion 23d which connects two opposite flat surfaces 23e.

[0153] Each thrust plate 160 is movable inside a respective hole 23h which extends in the shaft 23 at the enlarged portion 23d of the shaft.

[0154] Each hole 23h extends along a direction perpendicular to the rotation axis X and opens into one of the two opposite flat surfaces 23e.

[0155] Each hole 23h is connected to the hole 23f.

[0156] The two holes 23h are substantially aligned and can be connected together to define a single through hole 23h.

[0157] The thrust pin 159, when thrust inside the hole 23f and in contact with the two thrust plates 160, causes the thrust plates to move in the respective holes 23h.

[0158] The first hole 23f and each second hole 23h are substantially perpendicular to each other.

[0159] The thrust pin 159 and each thrust plate 160 comprise respective substantially wedge-shaped end portions 159a, 160a configured to abut each other. Preferably, the aforesaid substantially wedge-shaped surfaces 159a, 160a are inclined by about 45° with respect to the rotation axis X, but they can also be inclined by different angles, including angles comprised between 15° and 75°. The choice of this angle determines the adjustment sensitivity.

[0160] The thrust pin 159 is actuated by a pin 161 screwed into the first hole 23f. The pin 161 is fitted with a shaped recess 161a configured to be coupled with a tool (not shown) to be used for the initial adjustment of the derailleur 10. In the example shown, the shaped recess 161a is hexagonal and is configured to be coupled with a corresponding tool, for example a hexagonal wrench. Figure 4

[0161] Each hole 23h and each thrust plate 160 are arranged in an internal position with respect to the respective thrust member 56, which in this case also comprises a plurality of disc springs 57.

[0162] Since no washer is provided, each substantially cylindrical base 53a of the jaw 54 is configured to house at least a portion of the disc spring 57.

[0163] Figure 6 and Figure 7 A portion of a third preferred embodiment of a bicycle derailleur 10 according to the present application is shown. The parts not shown are the same as those shown in Figures 1 to 3

[0164] Figure 6 and Figure 7 The parts of the bicycle derailleur 10 according to Figures 1 to 3 are similar or functionally equivalent to those of the bicycle derailleur 10 according to

[0165] Figure 6 and Figure 7 The bicycle derailleur 10 according to Figures 1 to 3 differs from the bicycle derailleur 10 according to

[0166] In Figure 6 and​​Figure 7 In the non-limiting example shown, the elastic element 256 is a helical spring.

[0167] The bushing 224 is arranged between the through hole 223i and the elastic element 256. The bushing 224 helps to prevent unwanted axial movements of the helical spring.

[0168] The elastic element 256 is arranged in a radially internal position with respect to the two opposite jaws 54.

[0169] Therefore, the elastic element 256 passes through the shaft 23 and pushes, at its two ends, the two jaws 54, thereby pressing the two opposite friction surfaces 52 against the radially internal surface 86a of the annular element 86 with the same force.

[0170] Each jaw 54 is provided with a respective substantially cylindrical seat 53a configured to house a respective end of the elastic element 256.

[0171] Figure 8 and Figure 9 A portion of a fourth preferred embodiment of the bicycle shifting device 10 according to the present application is shown. The parts not shown are identical to those shown in Figures 1 to 3 .

[0172] Figure 8 and Figure 9 The parts of the bicycle shifting device 10 according to Figures 1 to 3 that are similar or functionally equivalent to those of the bicycle shifting device 10 according to are indicated with the same reference numbers and, for their description, reference should be made to what has already been described above.

[0173] Figure 8 Figure 9 The bicycle shifting device 10 according to Figures 1 to 3 differs from the bicycle shifting device 10 according to mainly in that the adjustment device 58 comprises a spacing element 358 having a predetermined thickness and housed in a through hole 223i made in the shaft 23 along a direction perpendicular to the rotation axis X. In particular, the through hole 223i is made at the enlarged portion 23d of the shaft 23 and opens onto two opposite flat surfaces 23e.

[0174] Figure 8 Moreover, in the non-limiting example shown, the thrust member 56 comprises a plurality of disc springs 56 arranged on opposite sides with respect to the spacing element 358. The disc springs 57 are at least partially housed in the through hole 223i. Figure 9

[0175] ​The bushing 224 is arranged between the through hole 223i and the spacer element 358. The disc spring 57 is housed at least partially inside the bushing 224. The bushing 224 helps to prevent unwanted axial movements of the disc spring 57.

[0176] The spacer element 358 and the disc spring 57 are arranged in a radially inner position with respect to the two opposite jaws 54.

[0177] The set of disc springs 57 pushes the two opposite jaws 54 so that the two opposite friction surfaces 52 press against the one-way rotation device 80 with the same force.

[0178] Each jaw 54 is provided with a respective substantially cylindrical seat 53a configured to house a portion of the disc spring 57.

[0179] The substantially cylindrical seat 53a helps to prevent unwanted axial movements of the disc spring 57.

[0180] Figure 10 A fifth preferred embodiment of the bicycle shifting device 10 according to the present application is shown. Figure 11 A portion of this embodiment is shown.

[0181] Figure 10 The components of the bicycle shifting device 10 of Figure 11 are similar or functionally equivalent to those of the bicycle shifting device 10 of Figures 1 to 3 and for the description of these components reference should be made to what has been described above.

[0182] Figure 10 The bicycle shifting device 10 of Figure 11 differs from the bicycle shifting device 10 of Figures 1 to 3 mainly in that the damping device 50 is arranged in a radially inner position with respect to the inner ring 84 of the radial bearing of the one-way rotation device 80. Therefore, in this case, the annular element 86 is not provided.

[0183] Therefore, the friction surfaces 52 of the jaws 54 directly exert a thrust force on the inner ring 84 of the radial bearing.

[0184] Also in this case, the radial bearing is preferably a roller bearing.

[0185] As shown in Figure 10 , a fixing element 462, provided with a threaded shank 463 and a head 464, is fixed to the outer plate 22 of the rocker arm 20.

[0186] The shank 463 extends coaxially to the rotation axis X and passes through a through hole 22a of the outer plate 22.

[0187] The head 464 is configured to be housed in axial abutment in a housing seat provided in the outer plate 22.

[0188] The fixing element 462 can be joined to the outer plate 22 by co-moulding, gluing, interference fitting or in any other manner which is conventional per se.

[0189] The end 23a of the shaft 23 has a threaded blind hole 423a in which the threaded shank 463 of the fixing element 462 is screwed.

[0190] The shaft 23 can thus be rotated with the rocker arm 20 as a unit with respect to the second body 36 about the rotation axis X.

[0191] The shaft 23 comprises an end 23a and an enlarged portion 23d. In this case, the cylindrical portion 23c shown in the previous figures is not provided.

[0192] The damping device 50 is arranged at the enlarged portion 23d and between the enlarged portion 23d itself and the inner ring 84 of the radial bearing.

[0193] Similarly to the shift device 10 of Figures 1 to 3 , Figure 10 and Figure 11 the damping device 50 of the shift device comprises two friction surfaces 52 which extend axially along a direction substantially parallel to the rotation axis X and which extend circumferentially about the rotation axis X for an arc of circumference having a centre on the rotation axis X and having a central angle which is less than 180°, preferably comprised between 80° and 160°, more preferably between 110° and 140°, even more preferably equal to about 125°.

[0194] The two friction surfaces 52 are arranged on opposite sides with respect to the rotation axis X, i.e. at about 180° from each other.

[0195] Each friction surface 52 is defined on a respective jaw 54 which is identical to the one described previously.

[0196] The helical return spring 40 is axially adjacent to the inner ring 84. In particular, the helical return spring 40 is arranged axially between the inner ring 84 of the radial bearing and the rocker arm 20. The damping device 50 is thus in axially adjacent position with respect to the helical return spring 40.

[0197] Similarly to the shift device 10 of Figures 1 to 3 , the enlarged portion 23d comprises two opposite flat surfaces 23e, each facing a respective jaw 54.

[0198] Figure 10 and Figure 11The shifting device 10 includes a pair of axially adjacent surfaces 451a, 451b, which are arranged on opposite sides of the damping device 50 and are configured to prevent axial movement of the gripper 54.

[0199] The axially abutting surface 451a is manufactured as a single piece with the shaft 23. Specifically, this axially abutting surface is arranged between the enlarged portion 23d and the end portion 23a. Figure 10 and Figure 11 In the unrestricted example shown, the axially adjacent surface 451a is formed substantially at the middle of the shaft 23.

[0200] On the other hand, the axially adjacent surface 451b is defined by a flange 452, which is associated with a surface of the enlarged portion 23d of the shaft 23, opposite the surface facing the end portion 23a. Figure 10 In the non-restricted example shown, flange 452 is secured to shaft 23 by screw 451c.

[0201] The gripper 54 has two opposite axially abutting surfaces 54a, which are axially accommodated between axially abutting surfaces 451a, 451b with a suitable gap to prevent these axially abutting surfaces 54a from sliding.

[0202] Figure 12 A sixth preferred embodiment of the bicycle shifting device 10 according to the present invention is shown. Figure 13 A portion of this embodiment is shown.

[0203] Figure 12 and Figure 13 The bicycle shift mechanism 10 and Figure 10 and Figure 11 The components of the bicycle shift mechanism 10 that are similar to or functionally equivalent to those components are indicated by the same reference numerals, and the description of these components should refer to the description already provided above.

[0204] Figure 12 and Figure 13 Bicycle shift mechanism 10 and Figure 10 and Figure 11 The main difference in the bicycle shifting device 10 is that the adjustment device 58 includes a preload device 158, which includes a thrust pin 159 and a pair of opposing thrust plates 160.

[0205] Preloading device 158 is exactly the same as the reference above. Figure 4 and Figure 5 The preloading device described in the second embodiment of the shifting device 10 shown.

[0206] Of course, the person skilled in the art can make various modifications and variants to the various embodiments of the bicycle shifting device described above, in order to meet specific and contingent requirements, all of which, in any case, are within the scope of protection of the present application, as defined by the claims appended hereto.

[0207] In particular, Figure 10 and Figure 11 The damping device 50 shown in Figure 6 and Figure 7 may be replaced by the damping device 50 shown in Figure 8 and Figure 9 Generally, the person skilled in the art can combine the features of the different embodiments of the application described and shown herein, as required.

[0208] Although the radial bearing shown in Figures 10 to 13 is axially adjacent to the helical return spring 40, there are embodiments in which the radial bearing is radially inner with respect to the helical return spring 40, thus providing a damping device 50 with low radial bulk or a helical return spring 40 with increased diameter, thereby making the shifting device 10 more axially compact.

Claims

1. A bicycle gear shifting device (10), comprising: - First body (34), the first body (34) is configured to be associated with a bicycle frame; - A second body (36), which is connected to the first body (34) and is movable relative to the first body (34); - A rocker arm (20) rotatably connected to the second body (36) about a rotation axis (X); - A shaft (23), which extends coaxially with the rotation axis (X) and is fixedly associated with the rocker arm (20); - A one-way rotating device (80) is operatively arranged between the shaft (23) and the second body (36) and is configured to allow the shaft (23) to rotate about the axis of rotation (X) only in a first rotational direction relative to the second body (36); - A first elastic element (40), associated with the second body (36) and the rocker arm (20), and configured to push the rocker arm (20) to rotate about the axis of rotation (X) in the first rotational direction; and - Damping device (50), which is operatively arranged between the shaft (23) and the one-way rotating device (80) and is configured to generate friction when the rocker arm (20) moves about the axis of rotation (X) in a second rotation direction opposite to the first rotation direction; The damping device (50) is characterized in that it includes at least two friction surfaces (52) that extend axially in a direction substantially parallel to the axis of rotation (X) and are in contact with the unidirectional rotation device (80).

2. The shifting device (10) according to claim 1, wherein, Each of the at least two friction surfaces (52) extends circumferentially around the axis of rotation (X) in an arc of a certain outer circumference, the center of the outer circumference arc being on the axis of rotation (X) and having a central angle of less than 180°.

3. The shifting device (10) according to claim 1, wherein, The damping device (50) includes at least one thrust member (56) configured to push the at least one friction surface (52) against the unidirectional rotating device (80) under a predetermined load.

4. The shifting device (10) according to claim 3, wherein, The at least one thrust member (56) includes a second elastic element (256) which is received in a through hole (223i) formed in the shaft (23) in a direction perpendicular to the axis of rotation (X), and the second elastic element (256) is arranged at a radially inward position relative to the at least two friction surfaces (52).

5. The shifting device (10) according to claim 3, wherein, The at least one thrust member (56) includes at least one disc spring (57) or at least one helical spring arranged between the shaft (23) and the at least one friction surface (52).

6. The shifting device (10) according to claim 3, wherein, The damping device (50) includes an adjustment device (58) configured to adjust the predetermined load.

7. The shifting device (10) according to claim 6, wherein, The adjusting device (58) includes at least one first spacer element (59) having a predetermined thickness. The at least one first spacer element (59) and the at least one thrust member (56) are respectively arranged between the at least one friction surface (52) and the shaft (23).

8. The shifting device (10) according to claim 6, wherein, The adjusting device (58) includes a preloading device (158) comprising a thrust pin (159) movable in a first hole (23f) extending in the shaft (23) in a first direction perpendicular to the axis of rotation (X), and the thrust pin (159) applying a thrust on at least one thrust plate (160) movable in a second hole (23h) connected to the first hole (23f) and extending in the shaft (23) in a second direction perpendicular to the axis of rotation (X), wherein the second hole (23h) is arranged at a radially inward position relative to the at least one thrust member.

9. The shifting device (10) according to claim 6, wherein, The adjusting device (58) includes a second spacer element (358) having a predetermined thickness, the second spacer element (358) being received in a through hole (223i) formed in the shaft (23) in a direction perpendicular to the axis of rotation (X), and the second spacer element (358) being arranged at a radially inward position relative to the at least two friction surfaces (52). The at least one thrust member (56) includes a plurality of disc springs (57) housed inside a bushing (224) which is housed in the through hole (223i) and the plurality of disc springs (57) are arranged on opposite sides of the second spacer element (358).

10. The shifting device (10) according to claim 3, wherein, The shaft (23) includes an enlargement (23d) at a radially inward position relative to the damping device (50), the enlargement (23d) including at least one flat surface (23e).

11. The shifting device (10) according to claim 10, wherein, The damping device (50) includes an adjusting device (58) configured to adjust the predetermined load. The adjustment device (58) is arranged at the enlarged portion (23d).

12. The shifting device (10) according to claim 1, wherein, The unidirectional rotating device (80) includes a radial bearing having an outer ring (82) and an inner ring (84), the outer ring (82) being fixedly associated with the second body (36), and the inner ring (84) being operatively associated with the at least one friction surface (52). The damping device (50) is at least partially arranged in a radially inward position relative to the inner ring (84), or in a radially inward position relative to the annular element (86), which is fixedly associated with and axially adjacent to the inner ring (84).

13. The shifting device (10) according to claim 1, comprising a pair of axially abutting surfaces (51a, 85; 451a, 451b) arranged on opposite sides of the damping device (50), and the axially abutting surfaces (51a, 85; 451a, 451b) configured to prevent axial movement of the damping device (50).

14. The shifting device (10) according to claim 1, wherein, The first elastic element (40) includes a helical return spring, and The damping device (50) is at least partially arranged in a radially inward position relative to the return spring, or arranged in an axially adjacent position relative to the return spring.

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