Rear derailleur with damping function

Abstract

A rear derailleur with damping function, comprising: a fixed portion having a frame connecting portion and a first pivoting portion connected thereto; a connecting rod assembly comprising a first connecting rod and a second connecting rod, one end of the first connecting rod and one end of the second connecting rod each pivotally connected to the first pivot portion; a movable portion having a second pivot portion and a seat connected thereto, the other end of the first connecting rod and the other end of the second connecting rod being pivotally connected to the second pivot portion, such that the first pivot portion, the connecting rod assembly, and the second pivot portion form a four-bar linkage, and the seat has a shaft hole; a chain guide portion having a shift rocker and a shaft member connected thereto, the shift rocker being rotatably coupled to a guide pulley and a tension pulley, and the shaft member being passed through the shaft hole; an elastic member located between and connected to the seat and the chain guide portion, providing a biasing force for rotating the chain guide portion; and a damping assembly comprising an inner ring, an outer ring, a plurality of first damping discs, a plurality of second damping discs, and at least one one-way bearing, wherein the inner ring is located in the outer ring, the outer surface of the inner ring is combined with the first damping discs, the outer ring is fixed to the seat, the inner surface of the outer ring is combined with the second damping discs, the first damping discs and the second damping discs are arranged alternately and at a distance from each other, a damping material is filled in the space between the first damping discs and the second damping discs, the at least one one-way bearing is snapped into the inner surface of the inner ring and engaged with the shaft member, and the shaft member is freely rotatable relative to the inner ring in a first direction via the at least one one-way bearing; wherein, when the shaft member of the chain guide portion drives the first damping discs of the inner ring for rotation in a second direction opposite to the first direction via the at least one one-way bearing, the damping material provides damping upon rotation of the first damping discs relative to the second damping discs.

Description

Field of the InventionThe present invention relates to a bicycle transmission, and more particularly to a transmission having a damping function.Prior ArtAs bicycles have become more widely used, they have evolved from a simple means of transportation to an important part of recreational design. In recent years, bicycles with shifting functions such as mountain bikes and racing bicycles have come on the market according to increasing market demand.As a rule, in a bicycle, a torsion spring in the derailleur mechanism ensures that the chain remains tensioned by a biasing force acting in the direction of rotation and that smooth driving is thus ensured. When driving on forest roads or uneven terrain, however, obstacles such as stones or unevenness may cause the torsion spring of the gearshift mechanism not to return immediately to its initial position as a result of vibrations. In such cases, the prestressing force can temporarily be omitted or reduced, as a result of which the chain is no longer sufficiently tensioned and problems such as chain strike, chain shedding, gear jumps or lost motion can occur.Therefore, the conventional transmission mechanisms for bicycles have not yet been matured and need improvement.Object of the InventionThe object of the present invention is to provide a derailleur with damping function to avoid problems such as chain shedding, gear jumps or lost motion during bicycle travel on uneven terrain.To achieve the above object, the present invention provides a derailleur with a damping function, including a fixed portion, a connecting rod assembly, a movable portion, a chain guide portion, an elastic member, and a damping assembly, the fixed portion having a frame connecting portion and a first pivot portion connected thereto, the connecting rod assembly including a first connecting rod and a second connecting rod, and one end of the first connecting rod and one end of the second connecting rod are each pivotally connected to the first pivot portion, the movable portion having a second pivot portion and a seat connected thereto, the other end of the first connecting rod and the other end of the second connecting rod are each pivotally connected to the second pivot portion, such that the first pivot portion, the connecting rod assembly, and the second pivot portion form a four-bar linkage, and the seat has a shaft hole, wherein the chain guide portion has a shift rocker and a shaft member connected thereto, the shift rocker is rotatably hinged to a guide roller and a tension roller, and the shaft member is passed through the shaft hole, wherein the elastic member is located between and connected to the seat and the chain guide portion and provides a biasing force for rotating the chain guide portion, wherein the damper assembly includes an inner ring, an outer ring, a plurality of first damper plates, a plurality of second damper plates, and at least one one one-way bearing, the inner ring is located in the outer ring, the outer surface of the inner ring is combined with the first damper plates, the outer ring is fixed to the seat, the inner surface of the outer ring is combined with the second damper plates, the first damper plates and the second damper plates are alternately and spaced apart from each other, a damping material filled in the space between the first damping plates and the second damping plates, the at least one one one-way bearing being snapped into the inner surface of the inner ring and engaged with the shaft member, and the shaft member being freely rotatable relative to the inner ring in a first direction via the at least one one one-way bearing, wherein when the shaft member of the chain guide portion drives the first damping plates of the inner ring to rotate in a second direction opposite to the first direction via the at least one one one-way bearing, the damping material provides damping upon rotation of the first damping plates relative to the second damping plates.The advantageous effects of the present invention consist in that the switching mechanism with damping function generates a damping effect by the interaction of the damping arrangement and the at least one one one-way bearing. When bicycling on uneven terrain, the shaft member drives the first cushion disks through the at least one one one-way bearing to be rotated relative to the second cushion disks. The damping material thereby brings about a damping during the rotation of the first damping disks relative to the second damping disks, whereby the speed and amplitude of the rotation of the shifting rocker of the chain guide section in the second direction carried out about the shaft element is slowed down and the chain, which is set in vibration by external influences, can thus quickly return to its initial position, which minimizes the risk of a chain shedding due to inadequate chain tension.Brief Description of the DrawingsFIG. 1 shows a front view of a preferred exemplary embodiment of the derailleur with damping function according to the invention; FIG. 2 shows a top view of the preferred exemplary embodiment of the derailleur according to the invention with damping function; FIG. 3 shows an exploded view of the preferred exemplary embodiment of the derailleur with damping function according to the invention; FIG. 4 is an exploded view of the chain guide portion of the preferred embodiment of the damper transmission according to the present invention; FIG. 5 shows an exploded view of the damping arrangement of the preferred exemplary embodiment of the derailleur with damping function according to the invention; FIG. 6 shows an exploded view of the damping arrangement of the preferred exemplary embodiment of the derailleur with damping function according to the invention from another perspective; FIG. 7 is a sectional view taken along line 7- 7 of FIG. 1 ; FIG. 8 shows an enlarged partial view of the region marked A in FIG. 6 ; FIG. 9 is a sectional view taken along section line 9-9 of FIG. 2.DETAILED DESCRIPTION OF THE EMBODIMENTTo better illustrate the present invention, a preferred exemplary embodiment is explained in detail below with reference to FIGS. 1 to 3. Reference is made to Figures 1 to 3 which show a preferred embodiment of the damping action derailleur 100 according to the invention. The transmission with damper function 100 includes a fixed portion 10, a connecting rod assembly 20, a movable portion 30, a chain guide portion 40, an elastic member 50, and a damper assembly 60.The fixed portion 10 is for combining with a bicycle frame and is located on the outside of the rear chainring assembly of a bicycle. As shown in FIG. 1, the fixed portion 10 includes a frame connecting portion 14 and a first pivot portion 12 connected thereto, the frame connecting portion 14 being for connection to the bicycle frame, the first pivot portion 12 having opposite first pivot ends 12 a, and the first pivot ends 12 abeing pivotally connected to the connecting rod assembly 20, respectively.One end of the connecting rod assembly 20 is pivotally connected to the fixed portion 10, while the movable portion 30 is pivotally connected to the other end of the connecting rod assembly 20. The connecting rod assembly 20 comprises a first connecting rod 22 and a second connecting rod 24, wherein one end of the first connecting rod 22 and one end of the second connecting rod 24 are each pivotably connected to the first pivoting portion 12 of the fixed portion 10 and the other ends of the first connecting rod 22 and the second connecting rod 24 are each pivotably connected to the second pivoting portion 32 of the movable portion 30, such that the first pivoting portion 12, the connecting rod assembly 20 and the second pivoting portion 32 form a four-bar linkage.Reference is made to FIGS. 1, 2 and 7. The movable portion 30 includes a second pivot portion 32 and a seat 34 connected thereto, the second pivot portion 32 having opposite second pivot ends 32 a, the second pivot ends 32 abeing pivotally connected to the link rod assembly 20, respectively, the seat 34 having a shaft hole 342, and a first chamber 344 being provided on a side of the seat 34 facing the shift rocker 42. The chain guide portion 40 includes a shift link 42 and a shaft member 44 connected thereto, the shaft member 44 passing through the shaft hole 342. The damper assembly 60 includes an outer housing 68, wherein the outer housing 68 is combined with the side of the seat 34 opposite the rocker arm 42, a second chamber 69 is provided in the outer housing 68, and the shaft hole 342 is continuously connected to the first chamber 344 and the second chamber 69. In assembly, the resilient member 50 is fitted onto the shaft member 44 and is located in the first chamber 344, with one end of the resilient member 50 being combined with the rocker arm 42 while the other end being combined with one side of the seat 34. Here, the elastic member 50 is a torsion spring that applies a biasing force to the shaft member 44 along a first direction D 1 (see FIG. 4 ). The first direction D 1 is a rotational direction in which the axis of the shaft member 44 serves as a fulcrum. Other elastic members that can provide a biasing force may be used alternatively to the torsion spring in the present preferred embodiment.Reference is made to FIGS. 4 and 7. The shift link 42 of the chain guide portion 40 is rotatably linked to a guide pulley 422 and a tension pulley 424, wherein the shaft member 44 connected to the shift link 42 includes a base shaft 442 and a pivot axis 446, the base shaft 442 is combined with the shift link 42 and includes a shaft rod 442 a, a screw hole 442 band an adjuster 442 c, the shaft rod 442 ais rotatably passed through the shaft hole 342, the screw hole 442 bis located at the outer end of the base shaft 442, and the adjuster 442 cis located at the inner end of the base shaft 442 and includes a plurality of adjustment holes 443 c therearound. One end of the elastic member 50 may be optionally combined with one of the adjustment holes 443 cto adjust the position of one end of the elastic member 50 and thus change the initial biasing force of the elastic member 50. The pivot shaft 446 has a first portion 446 a, a flange 446 band a second portion 446 carranged coaxially in sequence and connected to each other, the first portion 446 ais a threaded rod and inserted into the shaft hole 342 and screwed into the screw hole 442 bof the base shaft 442, the flange 446 bextends radially to the pivot shaft 446 and abuts on the periphery of one end of the shaft hole 342, and the outer end of the second portion 446 ccomprises a tool hole 446 d. A tool suitable for rotating the pivot axis 446 can be attached to the tool hole 446 d.Reference is made to Figures 4 to 9. The damper assembly 60 includes three one-way bearings 65, an inner ring 61, an outer ring 62, a plurality of first damper plates 63 and a plurality of second damper plates 64, the one-way bearings 65 being fitted on the shaft member 44 and locked to the inner surface of the inner ring 61, the outer surface of the inner ring 61 being combined with the first damper plates 63, the inner ring 61 being located in the outer ring 62, and the inner surface of the outer ring 62 being combined with the second damper plates 64 and fixed to the seat 34.In detail, the one-way bearings 65 are plugged onto the second section 446 cof the pivot axis 446 and each have a first latching groove 652. The inner surface of the inner ring 61 is provided with a first snap block 612 that is snap-fitted into the first snap grooves 652 to house the one-way bearings 65, the inner ring 61, and the first cushion washers 63 in the second chamber 69. The inner peripheries of the one-way bearings 65 are freely rotatable in the first direction D 1 relative to the outer peripheries thereof, so that the shaft member 44 is freely rotatable in the first direction D 1 relative to the inner ring 61 via the one-way bearings 65. In other preferred embodiments, the number of the one-way bearings 65 may also be selected as needed to be one or more than three.The first cushion washers 63 and the second cushion washers 64 are alternately and spaced apart from each other, the first cushion washers 63 are provided with second snap blocks 632, the outer surface of the inner ring 61 is provided with second snap grooves 614, and the second snap blocks 632 are snap-fitted into the corresponding second snap grooves 614, whereby the first cushion washers 63 are fixed to the inner ring 61, the second cushion washers 64 are provided with third snap blocks 642, the inner surface of the outer ring 62 is provided with third snap grooves 622, and the third snap blocks 642 are snap-fitted into the corresponding third snap grooves 622, whereby the second cushion washers 64 are fixed to the outer ring 62. When the shaft member 44 rotates in the first direction D 1, the first cushion disks 63 are not driven by the shaft member 44 to rotate relative to the second cushion disks 64 in the first direction D 1. Accordingly, when the bicycle chain engages with the guide roller 422 and the tension roller 424 of the ratchet 42, the ratchet 42 is rotated in the first direction D 1 by the biasing force of the elastic member 50 provided along the first direction D 1, thereby ensuring the chain tension.The direction of the axis of the shaft member 44 is defined as an axial direction L, the inner surface of the outer ring 62 has a first annular groove 624 on two sides along the axial direction L, the outer surface of the inner ring 61 has a second annular groove 616 on two sides along the axial direction L, and the first annular grooves 624 and the corresponding second annular grooves 616 are opposed to each other. The damping assembly 60 includes two seals 67 and a damping material 66, wherein a respective seal 67 is annular and has an inner edge 672 and an outer edge 674, the outer edge 674 and the inner edge 672 of one of the seals 67 are respectively snapped into one of the first annular grooves 624 and one of the second annular grooves 616, the outer edge 674 and the inner edge 672 of another seal 67 are respectively snapped into another first annular groove 624 and another second annular groove 616, and the seals are slidably disposed between the inner ring and the outer ring. The damping material 66 is filled in the space between the first damping disks 63 and the second damping disks 64, and is sealed between the outer ring 62 and the inner ring 61 by the seals 67. The damping material may be oil or a liquid having a high viscosity coefficient.When the bicycle chain is vibrated by an external force or the chain guide portion 40 is influenced by vibrations or external forces and the shift lever 42 vibrates downward due to inertia, the shaft member 44 of the chain guide portion 40 drives the first cushion plates 63 of the inner ring 61 to rotate in a second direction D 2 opposite to the first direction D 1 via the one-way bearings 65, the second direction D 2 also being a rotational direction in which the axis of the shaft member 44 serves as a fulcrum. In this case, the shaft member 44 drives the first cushion plates 63 to rotate relative to the second cushion plates 64 via the one-way bearings 65, and the rotation of the first cushion plates 63 relative to the second cushion plates 64 is damped by the damping material 66, whereby the speed and amplitude of the rotation of the shift link 42 of the chain guide portion 40 performed around the shaft member 44 in the second direction D is slowed down, and thus the chain vibrated by external influences can quickly return to its original position, which minimizes the risk of chain shedding due to insufficient chain tension.In the preferred embodiment, the damping force of the damping material 66 may be adjusted in various ways to meet different application requirements. Specifically, the damping effect can be influenced by the number of the first damping disks 63 and second damping disks 64. Additionally, the damping material 66 may be replaced with fluids having different viscosity coefficients to further optimize the damping assembly 60.In summary, it can be stated that, when a bicycle runs on forest roads or rough terrain, in the derailleur with damping function 100, a damping effect is generated by the cooperation of the damping arrangement 60 and the one-way bearings 65 in order to prevent the shifting link 42 from being overturned by external forces during the swinging or swinging of the chain, which could otherwise result in the shifting link 42 not being able to be reset in time by the biasing force of the elastic element 50 and the chain jumping off due to insufficient tension. With the present invention, the position of the switching rocker 42 can be promptly restored by the elastic member 50 to maintain the chain tension. This construction can ensure a stable engagement between the chain and the sprocket, thereby significantly reducing the risk of malfunctions of the bicycle due to a chain shedding.The foregoing description is only illustrative of a preferred embodiment of the invention and is not intended to limit the claims. All equivalent changes and modifications that can be made according to the description and drawings of the invention by a person skilled in the art fall within the scope of protection of the present invention.List of reference characters100 A transmission with damping function 10 fixed portion 12 first pivot portion 12 afirst pivot end 14 frame connection portion 20 link assembly 22 first link 24 second link 30 movable portion 32 second pivot portion 32 asecond pivot end 34 seat 342 shaft hole 344 first chamber 40 chain guide portion 42 shift lever 422 guide roller 424 tension roller 44 shaft member 442 base shaft 442 ashaft rod 442 bscrew hole 442 c adjuster 443 cadjustment hole 446 pivot axis 446 afirst portion 446 b flange 446 csecond portion 446 dtool hole 50 elastic member 60 damping assembly 61 inner ring 612 first ratchet block 614 second ratchet groove 616 second annular groove 62 outer ring 622 third ratchet groove 624 first annular groove 63 first damping disk 632 second ratchet block 64 second damping disk 642 third ratchet block 65 one-way bearing 652 first Locking groove 66 Damping material 67 Seal 672 Inner edge 674 Outer edge 68 Outer housing 69 Second chamber D 1 First direction D 2 Second direction L Axial direction

Claims

A derailleur with damping function, comprising: a fixed portion having a frame connecting portion and a first pivoting portion connected thereto; a connecting rod assembly comprising a first connecting rod and a second connecting rod, one end of the first connecting rod and one end of the second connecting rod each being pivotally connected to the first pivoting portion; a movable portion having a second pivoting portion and a seat connected thereto, the other end of the first connecting rod and the other end of the second connecting rod each being pivotally connected to the second pivoting portion such that the first pivoting portion, the connecting rod assembly, and the second pivoting portion form a four bar linkage, and the seat has a shaft hole; a chain guide portion having a shift link and a shaft member connected thereto, the shift link being rotatably linked to a guide roller and a tension roller, and the shaft member being passed through the shaft hole; an elastic member that is located between and connected to the seat and the chain guide portion and provides a biasing force for rotating the chain guide portion; and a damping assembly comprising an inner ring, an outer ring, a plurality of first damping disks, a plurality of second damping disks, and at least one one-way bearing, wherein the inner ring is located in the outer ring, the outer surface of the inner ring is combined with the first damping disks, the outer ring is fixed to the seat, the inner surface of the outer ring is combined with the second damping disks, the first damping disks and the second damping disks are arranged alternately and spaced apart from each other, a damping material is filled into the space between the first damping disks and the second damping disks, the at least one one-way bearing is snapped into the inner surface of the inner ring and engaged with the shaft element, and the shaft element is freely rotatable relative to the inner ring in a first direction via the at least one-way bearing; wherein, when the shaft member of the chain guide portion drives, via the at least one one-way bearing, the first cushion plates of the inner ring for rotation in a second direction opposite the first direction, the cushion material provides damping upon rotation of the first cushion plates relative to the second cushion plates.The derailleur with damping function according to claim 1, wherein the inner surface of the inner ring is provided with a first locking block, the at least one one-way bearing is provided with a first locking groove, and the first locking block is locked into the first locking groove.The derailleur with damping function according to claim 2, wherein the outer surface of the inner ring is provided with a second locking groove, a respective first damping disc is provided with a second locking block, and the second locking blocks are locked into the second locking groove.The transmission with damping function according to claim 3, wherein the inner surface of the outer ring is provided with a third detent groove, a respective third damping disk is provided with a third detent block, and the third detent blocks are detented in the third detent groove.The derailleur with damping function according to claim 1, wherein the damping arrangement comprises two seals, a respective seal being annular and having an inner edge and an outer edge.The transmission with damping function according to claim 5, wherein the direction of the axis of the shaft member is defined as an axial direction, the inner surface of the outer ring has a first annular groove on two sides along the axial direction, the outer surface of the inner ring has a second annular groove on two sides along the axial direction, and the first annular grooves and the corresponding second annular grooves are opposed to each other, the outer edge and the inner edge of one of the seals are respectively snapped into one of the first annular grooves and one of the second annular grooves, the outer edge and the inner edge of another seal are respectively snapped into another first annular groove and another second annular groove, and the seals are slidably disposed between the inner ring and the outer ring.The derailleur with damping function according to claim 1, wherein a first chamber is provided on the side of the seat facing the shift arm and the first chamber surrounds the shaft hole, wherein the damping arrangement comprises an outer housing, the outer housing is combined with the side of the seat facing away from the shift arm, a second chamber is provided in the seat, and the shaft hole is continuously connected to the first chamber and the second chamber.The transmission with damping function according to claim 7, wherein the elastic member is a torsion spring and is located in the first chamber, one end of the elastic member is combined with the shift rocker and the other end is combined with the seat.The derailleur with damping function according to claim 7, wherein the shaft member comprises a base shaft and a pivot axis, the base shaft is combined with the shift rocker and has a shaft rod, the shaft rod is rotatably passed through the shaft hole, and the outer end of the base shaft is provided with a screw hole, the pivot axis has a first portion, a flange, and a second portion that are successively arranged coaxially and connected to each other, the first portion is a threaded rod and inserted into the shaft hole, the flange abuts the periphery of an end of the shaft hole, and the outer end of the second portion has a tool hole.Switching mechanism with damping function according to Claim 9, in which the at least one one one-way bearing is plugged onto the second section of the pivot axis.

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