Damper and rear derailleur

Abstract

A damper and a rear derailleur. The damper comprises: a housing (21); a spindle (22), rotatably connected to the housing (21) around its own axis; a tension elastic member (23), provided between the spindle (22) and the housing (21); a sleeve (24), the space between the inner peripheral surface thereof and the outer peripheral surface of the spindle (22) being filled with damping grease capable of providing a viscous damping effect; and a locking spring (25), which is provided with a fixed end (251) and a free end (252) and helically extends from the fixed end (251) to the free end (252) in the axial direction of the spindle (22). When the sleeve (24) rotates relative to the housing (21) in a first rotational direction, the locking spring (25) retracts in the radial direction so as to tightly grip the sleeve (24) or the locking spring (25) expands in the radial direction so as to tightly press against the inner peripheral surface of the housing (21), thereby hindering the fixed end (251) and the sleeve (24) from keeping rotating in the first rotational direction.

Description

Dampers and rear derailleur

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese patent applications filed on April 17, 2025, with application number 2025104861239 entitled "Clamping Damper and Rear Derailleur" and application number 2025207332105 entitled "Narrowing Tensioner Roller Damper Damping Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of bicycle technology, and in particular to dampers and rear derailleurs. Background Technology

[0004] When a bicycle experiences severe bumps, the tensioner pulley tends to move rapidly toward the slack chain due to vertical inertia, which can easily cause the chain to fall off. This is especially noticeable on mountain bikes. To address this issue, dampers were developed to prevent the tensioner pulley from jumping abnormally.

[0005] Application content

[0006] This application aims to at least partially solve one of the technical problems existing in the related art. To this end, this application proposes a damper with significant damping effect and low requirements for subsequent maintenance, processing and installation accuracy.

[0007] This application also proposes a rear derailleur with the aforementioned damper.

[0008] A damper according to a first aspect embodiment of this application, having opposite first and second rotational directions, includes: a housing; a main shaft rotatably connected to the housing about its own axis, the main shaft being actuable in either the first or second rotational direction; a tensioning elastic element disposed between the main shaft and the housing, the tensioning elastic element being configured to apply a torque to the main shaft rotating in the second rotational direction; a sleeve located within the housing and rotatably fitted onto the main shaft, the inner circumferential surface of the sleeve and the outer circumferential surface of the main shaft being filled with damping grease capable of producing viscous damping; and a locking spring fitted outside the sleeve and located between the sleeve and the housing, the locking spring having a fixed end and a free end and extending helically from the fixed end about the axis of the main shaft to the free end, the wire diameter of the locking spring being smaller than that of the main shaft. The distance between the outer circumferential surface of the sleeve and the inner circumferential surface of the housing; the fixed end is mounted on the housing, the free end surrounds the outer circumferential surface of the sleeve, the inner diameter of the locking spring in its natural state is equal to the outer circumferential surface diameter of the sleeve, and when the sleeve rotates relative to the housing in a first rotational direction, the locking spring contracts radially to hold the sleeve tightly and prevent the sleeve from continuing to rotate in the first rotational direction; or, the fixed end is mounted on the sleeve, the free end extends outward against the inner circumferential surface of the housing, the outer diameter of the locking spring in its natural state is equal to the inner circumferential surface diameter of the housing, and when the sleeve rotates relative to the housing in a first rotational direction, the locking spring expands radially to tighten against the inner circumferential surface of the housing and prevent the fixed end and the sleeve from continuing to rotate in the first rotational direction.

[0009] It has at least the following beneficial effects: The damper's main shaft is configured as the swing center of the tensioner wheel. The main shaft rotates around its own axis and is connected to the housing. A tensioning elastic element is provided between the main shaft and the housing. The tensioning elastic element can apply a torque to the main shaft in the second rotation direction, that is, apply a tensioning force to the tensioner wheel and the chain. Under normal bicycle riding conditions, the tensioning elastic element is sufficient to meet the tensioning wheel's chain tensioning needs. A sleeve is rotatably fitted around the main shaft. The inner circumferential surface of the sleeve and the outer circumferential surface of the main shaft are filled with damping grease that can produce viscous damping. A locking mechanism is provided between the sleeve and the housing. The spring, specifically the locking spring, extends spirally from a fixed end around the axis of the main shaft to a free end. The fixed end is mounted on the housing, and the free end encircles the outer circumference of the sleeve; alternatively, the fixed end is mounted on the sleeve, and the free end extends outward against the inner circumference of the housing. When the bicycle experiences severe bumps, if the tensioner wheel tends to move rapidly towards the direction of the slack chain, it needs to drive the main shaft to rotate rapidly in the first rotation direction. Due to the significant viscous damping effect generated by the damping grease under rapid tension and impact, the main shaft can drive the sleeve to rotate in the first rotation direction through the damping grease. After a small rotation, the locking spring can quickly grip the sleeve or push it outward against the inner circumference of the housing to prevent the sleeve from continuing to rotate in the first rotation direction, generating significant damping. This, in turn, prevents the main shaft and tension wheel from continuing to rotate, preventing chain slippage. If the tension wheel has a tendency to move rapidly towards the chain tensioning direction, it will cause the sleeve to rotate with the main shaft in the second rotation direction. The locking spring will gradually disengage from the outer circumference of the sleeve or the inner circumference of the housing, allowing the sleeve to rotate smoothly with the main shaft with minimal resistance. The tension of the chain itself will then hinder the tension wheel. Continued operation will prevent chain slippage. When the rear derailleur is shifting gears normally, the tension wheel and the main shaft rotate synchronously and uniformly in either the first or second rotation direction. The speed is much lower than when a bicycle encounters a bump. When the damping grease is subjected to slow pulling and impact, the viscous damping effect is small, and the sleeve hardly follows the rotation of the main shaft. The resistance to gear shifting is very small and will not affect the normal shifting of the rear derailleur. The unidirectional damping effect of the damper is obvious, and the damping response is rapid. The ingenious structural design requires low precision in later maintenance, processing, and installation.

[0010] According to some embodiments of this application, the spindle is fixedly installed with an outwardly protruding expansion sleeve at the position corresponding to the sleeve, the sleeve is rotatably sleeved on the expansion sleeve, and the damping grease is filled between the outer peripheral surface of the expansion sleeve and the inner peripheral surface of the sleeve.

[0011] According to some embodiments of this application, the sleeve is stepped and has a stepped end face and two inner circumferential surfaces with different inner diameters. A first sealing ring is provided between the outer circumferential surface of the expanding sleeve and one of the inner circumferential surfaces of the sleeve, and a second sealing ring is provided between the outer circumferential surface of the spindle and the other inner circumferential surface of the sleeve. The first sealing ring, the stepped end face, the two inner circumferential surfaces of the sleeve, the second sealing ring, the outer circumferential surface of the spindle, the end face of the expanding sleeve facing the stepped end face, and the outer circumferential surface of the expanding sleeve enclose a ring-shaped cavity, which is configured to be filled with the damping grease.

[0012] According to some embodiments of this application, the expanding sleeve is provided with a first sealing groove along the circumference, the main shaft is provided with a second sealing groove along the circumference, and the first sealing ring and the second sealing ring are respectively constrained in the first sealing groove and the second sealing groove.

[0013] According to some embodiments of this application, the spindle has a groove along the circumference, and a retaining spring is installed in the groove. The retaining spring and the end face of the expanded sleeve facing the stepped end face together constrain the axial position of the sleeve relative to the spindle.

[0014] According to some embodiments of this application, the housing includes a rotating sidewall, an end cap disposed at one end of the rotating sidewall, and a middle shell disposed inside the rotating sidewall. The main shaft is rotatably connected to the end cap, the locking spring is located between the rotating sidewall and the sleeve, and the fixed end is mounted on the middle shell or the sleeve.

[0015] According to some embodiments of this application, one end of the spindle is stopped by the end cap in the axial direction, and the stepped end face is stopped by the middle shell in the axial direction. The end cap and the middle shell together constrain the axial position of the spindle.

[0016] According to some embodiments of this application, a rotating cover is driven to one end of the main shaft away from the end cover, the rotating cover is inserted into the other end of the rotating sidewall, the tensioning elastic element is a torsion spring, and the two torsion arms of the tensioning elastic element are respectively connected to the rotating cover and the middle shell.

[0017] According to some embodiments of this application, a rotating cover is installed at one end of the main shaft, the tensioning elastic element is a torsion spring and is axially disposed between the rotating cover and the housing, the tensioning elastic element is configured to apply a torque to the rotating cover in a second rotation direction, the damper further includes an expanding sleeve located between the main shaft and the sleeve, the expanding sleeve is kinetically connected to the rotating cover, the expanding sleeve is rotatably connected to the housing about its own axis, the main shaft, the tensioning elastic element and the expanding sleeve are arranged sequentially from the inside to the outside, the sleeve is rotatably sleeved on the outside of the expanding sleeve, and the inner circumferential surface of the sleeve and the outer circumferential surface of the expanding sleeve are filled with the damping grease that can produce a viscous damping effect.

[0018] According to some embodiments of this application, a third sealing ring is provided between the end of the expanding sleeve away from the rotating cover and the sleeve, and a fourth sealing ring is provided between the end of the expanding sleeve near the rotating cover and the sleeve. The third sealing ring, the outer circumferential surface of the expanding sleeve, the fourth sealing ring and the inner circumferential surface of the sleeve form an annular cavity, and the annular cavity is configured to be filled with the damping grease.

[0019] According to some embodiments of this application, a first expansion shoulder is provided circumferentially towards the sleeve at one end away from the rotating cover on the outer circumferential surface of the expansion sleeve, and a second expansion shoulder is provided circumferentially towards the expansion sleeve at one end near the rotating cover on the inner circumferential surface of the sleeve, and both the first expansion shoulder and the second expansion shoulder are located in the annular cavity.

[0020] According to some embodiments of this application, the outer circumferential surface of the expanded diameter sleeve is provided with a third sealing groove along the circumferential direction, and the inner circumferential surface of the sleeve is provided with a fourth sealing groove along the circumferential direction. The third sealing ring and the fourth sealing ring are respectively constrained within the third sealing groove and the fourth sealing groove.

[0021] According to some embodiments of this application, a limiting pin is detachably installed on the housing, and the spindle is provided with an annular limiting groove along the circumferential direction. The limiting pin is inserted into the limiting groove to constrain the axial position of the spindle.

[0022] According to some embodiments of this application, the housing includes an outer cylindrical shell and an end shell. The rotating cover is inserted into one end of the outer cylindrical shell, and the end shell is connected to the other end of the outer cylindrical shell. The locking spring is located between the outer circumferential surface of the sleeve and the inner circumferential surface of the outer cylindrical shell. The wire diameter of the locking spring is smaller than the distance between the outer circumferential surface of the sleeve and the inner circumferential surface of the outer cylindrical shell. The main shaft is rotatably connected to the end shell. The end shell and the rotating cover together constrain the axial position of the expanded diameter sleeve and the sleeve. The fixed end is mounted on the end shell.

[0023] According to some embodiments of this application, the rotating cover is provided with a second external spline, and the expanding sleeve is provided with a second internal spline, wherein the second external spline and the second internal spline are connected in a mating manner.

[0024] According to some embodiments of this application, a first external spline is provided at one end of the spindle near the rotating cover, and a first internal spline is provided at the rotating cover. The first external spline and the first internal spline are connected in a mating manner. A threaded hole is provided at one end of the spindle near the rotating cover along its own axis. The threaded hole is fastened to the rotating cover by a fastener.

[0025] A rear derailleur according to a second aspect of this application includes: a main body; a damper according to the first aspect of this application, wherein the housing is mounted on the main body; and a chain guide assembly including a guide plate and a guide wheel and a tension wheel rotatably mounted on the guide plate, wherein the guide plate is fixedly connected to the rotating cover, and the tensioning elastic element is configured to apply a tensioning force to the tension wheel.

[0026] It has at least the following beneficial effects: This rear derailleur has all the beneficial effects brought about by the above-mentioned damper, which will not be repeated here.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0029] Figure 1 is a structural schematic diagram of the rear derailleur in one of the embodiments of this application from one perspective;

[0030] Figure 2 is a structural schematic diagram of the rear derailleur in another perspective of an embodiment of this application;

[0031] Figure 3 is a cross-sectional view of the rear derailleur in the first embodiment of this application;

[0032] Figure 4 is an exploded view of the damper in the first embodiment of this application;

[0033] Figure 5 is an exploded view of the spindle and sleeve in the first and second embodiments of this application;

[0034] Figure 6 is a schematic diagram of the cooperation between the housing and the locking spring in the first embodiment of this application;

[0035] Figure 7 is a cross-sectional view of the rear derailleur in the second embodiment of this application;

[0036] Figure 8 is an exploded view of the damper in the second embodiment of this application;

[0037] Figure 9 is a schematic diagram of the fit between the sleeve and the locking spring in the second embodiment of this application;

[0038] Figure 10 is a schematic diagram of the damper in the third embodiment of this application;

[0039] Figure 11 is a cross-sectional view of Figure 10;

[0040] Figure 12 is a magnified view of part A in Figure 11;

[0041] Figure 13 is a magnified view of part B in Figure 11;

[0042] Figure 14 is a schematic diagram of the decomposition of Figure 10;

[0043] Figure 15 is an exploded view of the expansion sleeve and the sleeve in the third embodiment of this application;

[0044] Figure 16 is an exploded view of the main shaft, rotating cover and expanding sleeve in the third embodiment of this application.

[0045] Reference numerals: Main body 1, damper 2, housing 21, rotating side wall 211, end cap 212, middle shell 213, outer cylinder shell 214, end shell 215, main shaft 22, second sealing groove 221, retaining groove 222, retaining spring 223, first external spline 224, limiting groove 225, threaded hole 226, tensioning elastic element 23, sleeve 24, stepped end face 241, first inner circumferential surface 242, second inner circumferential surface 243, second expansion shoulder 244, fourth sealing groove 245, lock 25. Tight spring, 251. Fixed end, 252. Free end, 26. Expanding sleeve, 261. First sealing groove, 262. First expansion shoulder, 263. Second sealing groove, 264. Second inner spline, 27. Rotating cover, 271. First inner spline, 272. Second outer spline, 28. Annular chamber, 281. First sealing ring, 282. Third sealing ring, 283. Fourth sealing ring, 284. Limiting pin, 29. Chain guide assembly, 31. Guide plate, 32. Guide wheel, 33. Detailed Implementation

[0046] In the description of this application, it should be understood that the orientation descriptions, such as the first rotation direction, the second rotation direction, the axial direction, the radial direction, etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] In the description of this application, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0048] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0049] Currently, some dampers use hydraulic damping, which has a relatively complex structure and requires high sealing performance of each component, thus demanding high precision in machining and installation. Other dampers use a combination of elastic elements and one-way bearings for damping. When dealing with fast and severe bumps, the damping spring needs to be subjected to a certain degree of impact before it can react and implement reverse damping. The reverse damping effect is often proportional to the stroke of the damping spring, resulting in a delayed response and an ineffective way to prevent chain slippage. While one-way bearings can provide smooth rotation and damped rotation for free rotation and locked rotation respectively, under frequent start-stop or high-load conditions, the rollers, ratchet teeth, and other parts of the one-way bearing are prone to wear or pitting due to impact loads. Regular maintenance is required to ensure lubrication, which demands a high level of professional operation from the rider.

[0050] Referring to Figures 1 to 16, this application discloses a damper, the damper 2 including a housing 21, a main shaft 22, a tensioning elastic element 23, a sleeve 24 and a locking spring 25.

[0051] Referring to Figures 3, 4, 7, 8, and 11, the main shaft 22 is rotatably connected to the housing 21 about its own axis. The main shaft 22 can be actuated in a first rotation direction or a second rotation direction, wherein the first rotation direction and the second rotation direction are opposite. The tensioning elastic element 23 is disposed between the main shaft 22 and the housing 21. Referring to Figures 1 and 2, the tensioning elastic element 23 is configured to apply a torque to the main shaft 22 rotating in the second rotation direction, that is, to apply a tensioning force to the tensioning wheel 33.

[0052] Referring to Figures 3, 5, 7 and 11, the sleeve 24 is located inside the housing 21 and rotatably mounted on the main shaft 22. The inner circumferential surface of the sleeve 24 and the outer circumferential surface of the main shaft 22 are filled with damping grease that can produce viscous damping. When subjected to rapid tensile impact, the damping grease can produce a large viscous damping effect, while when subjected to slower tensile impact, the viscous damping effect is smaller.

[0053] Referring to Figures 3, 4, 7, 8, 11, and 14, the housing 21 has a cylindrical inner circumferential surface. The locking spring 25 is sleeved outside the sleeve 24 and located between the sleeve 24 and the housing 21. The locking spring 25 has a fixed end 251 and a free end 252, and extends spirally from the fixed end 251 to the free end 252 around the axis of the main shaft 22. The wire diameter of the locking spring 25 is smaller than the distance between the outer circumferential surface of the sleeve 24 and the inner circumferential surface of the housing 21.

[0054] Regarding the connection relationship of the locking spring 25, this application has two implementation methods.

[0055] In the first and third embodiments, referring to Figures 3, 4, 6, 11, and 14, the fixed end 251 is mounted on the housing 21, and the free end 252 surrounds the outer circumferential surface of the sleeve 24. The inner diameter of the locking spring 25 in its natural state is equal to the outer circumferential surface diameter of the sleeve 24. It should be noted that, considering the actual manufacturing precision and consistency of the locking spring 25, in its natural state, the inner diameter of at least a portion of the helical section of the locking spring 25 does not exceed the outer circumferential surface diameter of the sleeve 24, so as to maintain the surrounding pressure applied by the locking spring 25 to the outer circumferential surface of the sleeve 24.

[0056] When the sleeve 24 rotates relative to the housing 21 in the first rotation direction, the frictional action exerted by the sleeve 24 on the locking spring 25 forces the free end 252 to rotate slightly in the first rotation direction and causes the locking spring 25 to contract radially. The reaction is very rapid, so that the locking spring 25 clamps the sleeve 24. The pressure between the locking spring 25 and the sleeve 24 increases significantly. The locking spring 25 is hindered in the radial direction by the sleeve 24 and cannot contract or rotate further. The frictional force exerted by the locking spring 25 on the sleeve 24 also increases significantly, thereby preventing the sleeve 24 from continuing to rotate in the first rotation direction.

[0057] When the sleeve 24 rotates relative to the housing 21 in the second rotation direction, the frictional action applied by the sleeve 24 to the locking spring 25 forces the free end 252 to rotate slightly in the second rotation direction and causes the locking spring 25 to expand radially. The response is very rapid, so that the locking spring 25 gradually loosens the outer circumferential surface of the sleeve 24. Since the wire diameter of the locking spring 25 is smaller than the distance between the outer circumferential surface of the sleeve 24 and the inner circumferential surface of the housing 21, the locking spring 25 has sufficient radial expansion space. The pressure between the locking spring 25 and the sleeve 24 is significantly reduced, allowing the sleeve 24 to rotate smoothly with very little resistance.

[0058] In the second embodiment, referring to Figures 7, 8 and 9, the fixed end 251 is mounted on the sleeve 24, and the free end 252 extends outward against the inner circumferential surface of the housing 21. The outer diameter of the locking spring 25 in its natural state is equal to the inner circumferential surface diameter of the housing 21. It should be noted that, considering the actual manufacturing precision and consistency of the locking spring 25, in its natural state, the outer diameter of at least a portion of the helical section of the locking spring 25 is not less than the inner circumferential surface diameter of the housing 21, so as to maintain the outward supporting pressure applied by the locking spring 25 to the inner circumferential surface of the housing 21.

[0059] When the sleeve 24 rotates relative to the housing 21 in the first rotation direction, the fixed end 251 follows the sleeve 24 and rotates slightly in the first rotation direction, forcing the locking spring 25 to expand radially. The reaction is very rapid, so that the locking spring 25 is stretched outward against the inner circumferential surface of the housing 21. The pressure between the locking spring 25 and the inner circumferential surface of the housing 21 increases significantly. However, the locking spring 25 is hindered in the radial direction by the inner circumferential surface of the housing 21 and cannot expand or rotate further. Since the fixed end 251 is fixedly connected to the sleeve, the fixed end 251 also prevents the sleeve 24 from continuing to rotate in the first rotation direction.

[0060] When the sleeve 24 rotates relative to the housing 21 in the second rotation direction, the fixed end 251 follows the sleeve 24 and rotates slightly in the second rotation direction, forcing the locking spring 25 to contract radially. The response is very rapid, so that the locking spring 25 releases the inner circumferential surface of the housing 21 inward. Since the wire diameter of the locking spring 25 is smaller than the distance between the outer circumferential surface of the sleeve 24 and the inner circumferential surface of the housing 21, the locking spring 25 has sufficient radial contraction space. The pressure between the locking spring 25 and the housing 21 is significantly reduced, allowing the locking spring 25 to rotate smoothly with the sleeve 24 with very little resistance.

[0061] In the first, second, and third embodiments, as long as the sleeve 24 rotates a very small angle relative to the housing 21 in the first rotation direction, the locking spring 25 can react quickly to achieve reverse damping. When the sleeve 24 rotates relative to the housing 21 in the second rotation direction, the locking spring 25 provides very little resistance to the sleeve 24, thus achieving unidirectional damping.

[0062] Referring to Figures 1, 2, 3 and 10, the damper 2 is applied to the rear derailleur. The main shaft 22 of the damper 2 is configured as the swing center of the tension wheel 33. The tensioning elastic element 23 can apply a torque to the main shaft 22 in the second rotation direction. Under normal bicycle riding conditions, the tensioning elastic element 23 is sufficient to meet the needs of the tension wheel 33 to tension the chain.

[0063] When the bicycle experiences severe bumps, if the tensioner 33 tends to move rapidly toward the direction of slack chain, it needs to drive the main shaft 22 to rotate rapidly in the first rotation direction. Due to the rapid pulling and impact of the damping grease, a large viscous damping effect is generated. The main shaft 22 can drive the sleeve 24 to rotate in the first rotation direction through the damping grease. After experiencing a small rotation amplitude, the locking spring 25 can quickly hold the sleeve 24 or push it outward against the inner circumference of the housing 21 to prevent the sleeve 24 from continuing to rotate in the first rotation direction, generating a large damping, thereby preventing the main shaft 22 and the tensioner 33 from continuing to rotate and preventing the chain from falling off.

[0064] If the tension wheel 33 has a tendency to move rapidly toward the direction of tensioning the chain, it will drive the sleeve 24 to rotate along the second rotation direction with the main shaft 22. The locking spring 25 will gradually disengage from the outer circumferential surface of the sleeve 24 or the inner circumferential surface of the housing 21, so that the sleeve 24 can rotate smoothly with the main shaft 22 with very little resistance. The tension of the chain itself will prevent the tension wheel 33 from continuing to move, and there will be no chain drop.

[0065] When the rear derailleur is shifting gears normally, the tension wheel 33 and the main shaft 22 rotate synchronously and uniformly in the first or second rotation direction. The speed is much smaller than when a bicycle encounters a bump. When the damping grease is subjected to a relatively slow pulling impact, the viscous damping effect is small. The sleeve 24 hardly follows the rotation of the main shaft 22, and the resistance to the gear shifting operation is very small. It will not affect the normal gear shifting of the rear derailleur. The unidirectional damping effect of the damper 2 is obvious, and the damping response is fast. The structure is ingeniously designed and has low requirements for later maintenance, processing and installation precision.

[0066] In the first and second embodiments of this application, referring to Figures 3, 5, and 7, a protruding expansion sleeve 26 is fixedly installed on the spindle 22 at the position corresponding to the sleeve 24. The sleeve 24 is rotatably fitted onto the expansion sleeve 26. Damping grease is filled between the outer circumferential surface of the expansion sleeve 26 and the inner circumferential surface of the sleeve 24. The expansion sleeve 26 has a larger outer diameter than the spindle 22, effectively increasing the contact area with the damping grease and enabling the damping grease to produce a greater viscous damping effect. It can be understood that the expansion sleeve 26 can be integrally formed with the spindle 22 through a rubber injection molding process, or it can be fixedly inserted into the spindle 22.

[0067] Referring to Figures 3, 5, and 7, in some embodiments, the sleeve 24 is stepped and has a stepped end face 241 and two inner circumferential surfaces with different inner diameters. The two inner circumferential surfaces with different inner diameters are a first inner circumferential surface 242 and a second inner circumferential surface 243, respectively. The outer ring of the stepped end face 241 is connected to the first inner circumferential surface 242, and the inner ring is connected to the second inner circumferential surface 243. A first sealing ring 281 is provided between the outer circumferential surface of the expanded diameter sleeve 26 and the first inner circumferential surface 242, and a second sealing ring 282 is provided between the outer circumferential surface of the main shaft 22 and the second inner circumferential surface 243.

[0068] The first sealing ring 281, the first inner circumferential surface 242, the stepped end face 241, the second inner circumferential surface 243, the second sealing ring 282, the outer circumferential surface of the main shaft 22, the end face of the expansion sleeve 26 facing the stepped end face 241, and the outer circumferential surface of the expansion sleeve 26 enclose to form an annular cavity 28. The annular cavity 28 is configured to be filled with damping grease to further increase the contact area between the damping grease and the main shaft 22, the sleeve 24, and the expansion sleeve 26.

[0069] Understandably, the expansion sleeve 26 and the main shaft 22 have good sealing properties, and the damping grease will not seep into the space between the expansion sleeve 26 and the main shaft 22.

[0070] In some embodiments, referring to Figures 3, 5 and 7, the expanded diameter sleeve 26 is provided with a first sealing groove 261 along the circumference, and the main shaft 22 is provided with a second sealing groove 221 along the circumference. The first sealing ring 281 and the second sealing ring 282 are respectively constrained in the first sealing groove 261 and the second sealing groove 221, which can effectively prevent the first sealing ring 281 and the second sealing ring 282 from slipping and shifting, thereby realizing the sealing function of the annular cavity 28.

[0071] Referring to Figures 4 and 9, in some embodiments, the spindle 22 has a groove 222 along the circumference, and a retaining spring 223 is installed in the groove 222. Referring further to Figures 3 and 7, the retaining spring 223 and the end face of the expansion sleeve 26 facing the stepped end face 241 together constrain the axial position of the sleeve 24 relative to the spindle 22, which facilitates the pre-assembly connection between the sleeve 24, the expansion sleeve 26 and the spindle 22, and then the whole assembly is installed into the housing 21.

[0072] It should be noted that there is a gap between the stepped end face 241 and the end face of the expanded sleeve 26 facing the stepped end face 241, which can be filled with damping grease, forming part of the annular chamber 28.

[0073] Referring to Figures 3 and 7, the housing 21 includes a rotating sidewall 211, an end cap 212 disposed at one end of the rotating sidewall 211, and a middle shell 213 disposed inside the rotating sidewall 211. The main shaft 22 is rotatably connected to the end cap 212. The inner circumferential surface of the rotating sidewall 211 is cylindrical. The locking spring 25 is located between the rotating sidewall 211 and the sleeve 24.

[0074] In the first embodiment, the fixed end 251 of the locking spring 25 is mounted on the middle shell 213; in the second embodiment, the free end 252 of the locking spring 25 is pushed outward against the inner circumferential surface of the rotating side wall 211.

[0075] Referring to Figures 3 and 7, one end of the main shaft 22 is stopped by the end cap 212 in the axial direction, and the stepped end face 241 of the sleeve 24 is stopped by the middle shell 213 in the axial direction. Since the snap ring 223 and the end face of the expansion sleeve 26 facing the stepped end face 241 jointly constrain the axial position of the sleeve 24 relative to the main shaft 22, the end cap 212 and the middle shell 213 jointly constrain the axial position of the main shaft 22. By reasonably designing the distance between the end cap 212 and the middle shell 213, sufficient clearance can be ensured between the stepped end face 241 and the end face of the expansion sleeve 26 facing the stepped end face 241.

[0076] In some embodiments of this application, referring to Figures 3, 4, 7 and 8, the end of the main shaft 22 away from the end cover 212 is connected to the rotating cover 27. The rotating cover 27 is inserted into the other end of the rotating side wall 211 to achieve the airtightness of the housing 21. The tensioning elastic element 23 is a torsion spring. The two torsion arms of the tensioning elastic element 23 are respectively connected to the rotating cover 27 and the middle housing 213. The tensioning elastic element 23 applies a torque to the rotating cover 27 in the second rotation direction to apply the tensioning chain force to the tensioning wheel 33.

[0077] Referring to Figure 2, the rotating cover 27 is configured as an intermediate component for the transmission between the tension wheel 33 and the main shaft 22, receiving the oscillating power transmitted from the tension wheel 33 to the main shaft 22, and the damping force transmitted from the main shaft 22 to the tension wheel 33.

[0078] In the third embodiment of this application, referring to Figures 10, 11 and 16, a rotating cover 27 is installed at one end of the main shaft 22. The tensioning elastic element 23 is a torsion spring and is axially disposed between the rotating cover 27 and the housing 21. The tensioning elastic element 23 is configured to apply a torque to the rotating cover 27 in the second rotation direction. The damper 2 also includes an expanding sleeve 26 located between the main shaft 22 and the sleeve 24. The expanding sleeve 26 is connected to the rotating cover 27 in a transmission manner. The expanding sleeve 26 is rotatably connected to the housing 21 about its own axis. The main shaft 22, the tensioning elastic element 23 and the expanding sleeve 26 are arranged sequentially from the inside to the outside. The sleeve 24 is rotatably sleeved on the outside of the expanding sleeve 26. The inner circumferential surface of the sleeve 24 and the outer circumferential surface of the expanding sleeve 26 are filled with damping grease that can produce viscous damping effect.

[0079] Referring to Figures 10, 11, and 14, since the tensioning elastic element 23, the expanding sleeve 26, the sleeve 24, and the locking spring 25 are arranged radially around the main shaft 22, the axial dimension of the main shaft 22 can be designed to be smaller. This reduces the width of the damper 2 and the rear derailleur, forming a narrow structure, reducing the risk of mechanical interference or component collisions. It also increases the gap between the rear derailleur and the freewheel assembly, expanding the space for routine maintenance operations such as chain disassembly and guide wheel cleaning.

[0080] In some embodiments, referring to Figures 11 and 15, a third sealing ring 283 is provided between the end of the expanding sleeve 26 away from the rotating cover 27 and the sleeve 24, and a fourth sealing ring 284 is provided between the end of the expanding sleeve 26 near the rotating cover 27 and the sleeve 24. The third sealing ring 283, the outer peripheral surface of the expanding sleeve 26, the fourth sealing ring 284 and the inner peripheral surface of the sleeve 24 enclose to form an annular cavity 28, which is configured to be filled with damping grease, thereby achieving a seal on the damping grease.

[0081] In some embodiments, referring to Figures 11 and 12, a first expansion shoulder 262 protrudes circumferentially toward the sleeve 24 at one end of the outer circumferential surface of the expansion sleeve 26 away from the rotating cover 27. Referring to Figures 11 and 13, a second expansion shoulder 244 protrudes circumferentially toward the expansion sleeve 26 at one end of the inner circumferential surface of the sleeve 24 near the rotating cover 27. The protrusion height of the second expansion shoulder 244 can be consistent with the protrusion height of the first expansion shoulder 262. Both the first expansion shoulder 262 and the second expansion shoulder 244 are located within the annular chamber 28, thereby ensuring the minimum radial thickness of the annular chamber 28. Moreover, the damping grease distributed between the outer circumferential surface of the expansion sleeve 26 and the inner circumferential surface of the sleeve 24 is relatively uniform, improving the damping effect.

[0082] Referring to Figures 12 and 13, the outer circumferential surface of the expanded sleeve 26 is provided with a third sealing groove 263, and the inner circumferential surface of the sleeve 24 is provided with a fourth sealing groove 245. The third sealing ring 283 and the fourth sealing ring 284 are respectively constrained within the third sealing groove 263 and the fourth sealing groove 245, which can effectively prevent the third sealing ring 283 and the fourth sealing ring 284 from slipping and shifting, thereby achieving good sealing performance of the annular chamber 28.

[0083] In some embodiments, referring to Figures 11, 14 and 16, a limiting pin 29 is detachably installed on the housing 21, and the spindle 22 has an annular limiting groove 225 along the circumferential direction. The limiting pin 29 is inserted into the limiting groove 225 to constrain the axial position of the spindle 22. Specifically, the spindle 22 can be inserted into the housing 21 first, and then the limiting pin 29 can be inserted to constrain the axial position of the spindle 22, so that the finally assembled spindle 22 and rotating cover 27 will not deviate along the axial direction of the spindle 22.

[0084] The limiting pin 29 can be inserted into the housing 21 along the axial direction perpendicular to the main shaft 22 and fastened to the housing 21 by threads to achieve a detachable connection.

[0085] In some embodiments, referring to Figures 10, 11, and 14, the housing 21 includes an outer cylindrical shell 214 and an end shell 215. The outer cylindrical shell 214 is cylindrical, and its inner circumferential surface is cylindrical. A rotating cover 27 is inserted into one end of the outer cylindrical shell 214, and the end shell 215 is connected to the other end of the outer cylindrical shell 214. A locking spring 25 is located between the outer circumferential surface of the sleeve 24 and the inner circumferential surface of the outer cylindrical shell 214. The wire diameter of the locking spring 25 is smaller than the distance between the outer circumferential surface of the sleeve 24 and the inner circumferential surface of the outer cylindrical shell 214, ensuring that the locking spring 25 has sufficient radial expansion space when it disengages from the outer circumferential surface of the sleeve 24.

[0086] Referring to Figure 11, the spindle 22 is rotatably connected to the end shell 215, and the fixed end 251 is installed on the end shell 215. The end shell 215 and the rotating cover 27 together constrain the axial position of the expanding sleeve 26 and the sleeve 24, preventing the expanding sleeve 26 and the sleeve 24 from shifting axially along the spindle 22.

[0087] Referring to Figures 10 and 16, the rotating cover 27 is provided with a second external spline 272, and the expanding sleeve 26 is provided with a second internal spline 264. The second external spline 272 and the second internal spline 264 are connected in a mating manner. The rotating cover 27 transmits rotational power to the expanding sleeve 26 through the second external spline 272, which facilitates the assembly between the expanding sleeve 26 and the rotating cover 27.

[0088] In the first, second, and third embodiments, referring to Figures 4, 8, 10, and 16, a first external spline 224 is provided on the end of the spindle 22 near the rotating cover 27, and a first internal spline 271 is provided on the rotating cover 27. The first external spline 224 and the first internal spline 271 are connected in a mating manner, and the rotating cover 27 transmits rotational power to the spindle 22 through the first internal spline 271. The spline connection structure facilitates the insertion and assembly between the spindle 22 and the rotating cover 27. A threaded hole 226 is provided on the end of the spindle 22 near the rotating cover 27 along its own axis. The threaded hole 226 is fastened to the rotating cover 27 by fasteners to achieve axial locking constraint between the two.

[0089] Referring to Figures 1 and 2, this application also discloses a rear derailleur, comprising: a main body 1, a damper 2 as described in the above embodiments, and a chain guide assembly 3.

[0090] The housing 21 is mounted on the main body 1. The chain guide assembly 3 includes a guide plate 31 and a guide wheel 32 and a tension wheel 33 rotatably mounted on the guide plate 31. The guide plate 31 is fixedly connected to the rotating cover 27. The tensioning elastic element 23 is configured to apply a torque to the main shaft 22 in the second rotation direction. The main shaft 22 is the swing center of the tension wheel 33, that is, the tensioning elastic element 23 is configured to apply a tensioning force to the tension wheel 33.

[0091] This rear derailleur has a significant one-way damping effect and a rapid damping response, which can effectively prevent the chain from falling off. It will not affect the normal shifting and gear changing operation of the bicycle. The structure is ingeniously designed and has low requirements for later maintenance, processing and installation precision.

[0092] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] Of course, this application is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of this application. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. Damper, wherein, Having opposite first and second rotational directions, including: case; A main shaft is rotatably connected to the housing about its own axis, and the main shaft can be actuated in a first rotational direction or a second rotational direction; A tensioning elastic element is disposed between the main shaft and the housing, and the tensioning elastic element is configured to apply a torque to the main shaft in a second rotational direction; A sleeve is located inside the housing and rotatably mounted on the main shaft. The inner circumferential surface of the sleeve and the outer circumferential surface of the main shaft are filled with damping grease that can produce viscous damping effect. A locking spring is sleeved outside the sleeve and located between the sleeve and the housing. The locking spring has a fixed end and a free end and extends spirally from the fixed end to the free end around the axis of the main shaft. The wire diameter of the locking spring is smaller than the distance between the outer circumferential surface of the sleeve and the inner circumferential surface of the housing. The fixed end is mounted on the housing, the free end surrounds the outer circumferential surface of the sleeve, the inner diameter of the locking spring in its natural state is equal to the outer circumferential diameter of the sleeve, and when the sleeve rotates relative to the housing in the first rotation direction, the locking spring contracts radially to hold the sleeve tightly and prevent the sleeve from continuing to rotate in the first rotation direction. Alternatively, the fixed end is mounted on the sleeve, and the free end extends outward against the inner circumferential surface of the housing. The outer diameter of the locking spring in its natural state is equal to the inner circumferential diameter of the housing. When the sleeve rotates relative to the housing in a first rotational direction, the locking spring expands radially to tighten against the inner circumferential surface of the housing and prevent the fixed end and the sleeve from continuing to rotate in the first rotational direction.

2. The damper according to claim 1, wherein, The main shaft is fixedly installed with an outwardly protruding expansion sleeve at the position corresponding to the sleeve. The sleeve is rotatably sleeved on the expansion sleeve. The damping grease is filled between the outer circumferential surface of the expansion sleeve and the inner circumferential surface of the sleeve.

3. The damper according to claim 2, wherein, The sleeve is stepped and has a stepped end face and two inner circumferential surfaces with different inner diameters. A first sealing ring is provided between the outer circumferential surface of the expanding sleeve and one of the inner circumferential surfaces of the sleeve. A second sealing ring is provided between the outer circumferential surface of the spindle and the other inner circumferential surface of the sleeve. The first sealing ring, the stepped end face, the two inner circumferential surfaces of the sleeve, the second sealing ring, the outer circumferential surface of the spindle, the end face of the expanding sleeve facing the stepped end face, and the outer circumferential surface of the expanding sleeve enclose a ring-shaped cavity, which is configured to be filled with the damping grease.

4. The damper according to claim 3, wherein, The expanding sleeve has a first sealing groove along its circumference, and the main shaft has a second sealing groove along its circumference. The first sealing ring and the second sealing ring are respectively constrained within the first sealing groove and the second sealing groove.

5. The damper according to claim 3, wherein, The main shaft has a groove along its circumference, and a retaining spring is installed in the groove. The retaining spring and the end face of the expanded sleeve facing the stepped end face together constrain the axial position of the sleeve relative to the main shaft.

6. The damper according to claim 5, wherein, The housing includes a rotating sidewall, an end cap disposed at one end of the rotating sidewall, and a middle shell disposed inside the rotating sidewall. The main shaft is rotatably connected to the end cap. The locking spring is located between the rotating sidewall and the sleeve. The fixed end is installed on the middle shell or the sleeve.

7. The damper according to claim 6, wherein, One end of the spindle is stopped by the end cap in the axial direction, and the stepped end face is stopped by the middle shell in the axial direction. The end cap and the middle shell together constrain the axial position of the spindle.

8. The damper according to claim 7, wherein, The main shaft is driven to a rotating cover at one end away from the end cover. The rotating cover is inserted into the other end of the rotating side wall. The tensioning elastic element is a torsion spring. The two torsion arms of the tensioning elastic element are respectively connected to the rotating cover and the middle shell.

9. The damper according to claim 1, wherein, A rotating cover is installed at one end of the main shaft. The tensioning elastic element is a torsion spring and is axially disposed between the rotating cover and the housing. The tensioning elastic element is configured to apply a torque to the rotating cover in a second rotation direction. The damper also includes an expanding sleeve located between the main shaft and the sleeve. The expanding sleeve is kinetically connected to the rotating cover and rotatably connected to the housing about its own axis. The main shaft, the tensioning elastic element, and the expanding sleeve are arranged sequentially from the inside to the outside. The sleeve is rotatably sleeved on the outside of the expanding sleeve. The inner circumferential surface of the sleeve and the outer circumferential surface of the expanding sleeve are filled with damping grease that can produce viscous damping effect.

10. The damper according to claim 9, wherein, A third sealing ring is provided between the end of the expanding sleeve away from the rotating cover and the sleeve, and a fourth sealing ring is provided between the end of the expanding sleeve near the rotating cover and the sleeve. The third sealing ring, the outer circumferential surface of the expanding sleeve, the fourth sealing ring and the inner circumferential surface of the sleeve form an annular cavity, which is configured to be filled with the damping grease.

11. The damper according to claim 10, wherein, On the outer circumferential surface of the expanding sleeve, a first expanding shoulder protrudes circumferentially towards the sleeve at one end away from the rotating cover, and on the inner circumferential surface of the sleeve, a second expanding shoulder protrudes circumferentially towards the expanding sleeve at one end near the rotating cover. Both the first expanding shoulder and the second expanding shoulder are located within the annular cavity.

12. The damper according to claim 11, wherein, The outer circumferential surface of the expanded sleeve is provided with a third sealing groove, and the inner circumferential surface of the sleeve is provided with a fourth sealing groove. The third sealing ring and the fourth sealing ring are respectively constrained within the third sealing groove and the fourth sealing groove.

13. The damper according to claim 9, wherein, A limiting pin is detachably installed on the housing, and the main shaft has an annular limiting groove along its circumference. The limiting pin is inserted into the limiting groove to constrain the axial position of the main shaft.

14. The damper according to claim 9, wherein, The housing includes an outer cylindrical shell and an end shell. The rotating cover is inserted into one end of the outer cylindrical shell, and the end shell is connected to the other end of the outer cylindrical shell. The locking spring is located between the outer circumferential surface of the sleeve and the inner circumferential surface of the outer cylindrical shell. The wire diameter of the locking spring is smaller than the distance between the outer circumferential surface of the sleeve and the inner circumferential surface of the outer cylindrical shell. The main shaft is rotatably connected to the end shell. The end shell and the rotating cover together constrain the axial position of the expanded diameter sleeve and the sleeve. The fixed end is installed on the end shell.

15. The damper according to claim 9, wherein, The rotating cover is provided with a second external spline, and the expanding sleeve is provided with a second internal spline. The second external spline and the second internal spline are connected in a mating manner.

16. The damper according to claim 8, 9 or 15, wherein, The spindle is provided with a first external spline at one end near the rotating cover, and the rotating cover is provided with a first internal spline. The first external spline and the first internal spline are connected in a mating manner. The spindle is provided with a threaded hole along its own axis at one end near the rotating cover, and the threaded hole is fastened to the rotating cover by a fastener.

17. Rear derailleur, wherein, include: main body; The damper as described in any one of claims 8 to 16, wherein the housing is mounted on the body; A chain guide assembly includes a guide plate and a guide wheel and a tension wheel rotatably mounted on the guide plate. The guide plate is fixedly connected to the rotating cover, and the tensioning elastic element is configured to apply a tensioning force to the tension wheel.

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