Novel crank assembly for bicycle

Abstract

The invention discloses a novel crank assembly for a bicycle, which comprises a transmission shaft inserted into a five-way structure of the bicycle in a penetrating manner; the non-driving end of the transmission shaft is provided with a locking part used for being fixedly connected with a non-driving side crank, and the driving end of the transmission shaft is provided with an axial screw hole. The side crank structure comprises a crank arm, and a compensation sleeve, a gap adjusting bolt, a guide sleeve and a connecting sleeve which are respectively arranged in a sleeve hole of the crank arm, the compensation sleeve is arranged at the driving end of the transmission shaft in a sleeving mode, and one end face of the compensation sleeve is used for abutting against a bearing of a five-way structure. The inner wall of the guide sleeve is matched with the compensation sleeve through threads and used for driving the compensation sleeve and the connecting sleeve to move axially. According to the technical scheme, the structure is simple, assembling is easy, the sediment invasion path can be effectively blocked, the axial fit clearance is eliminated, and therefore the defects that in the prior art, due to the fact that an adjusting component is completely exposed, stability is poor, and maintenance is difficult are overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of bicycles, and particularly relates to a novel crank assembly for bicycles. Background Art

[0002] Currently, connection head structures are respectively designed at the left and right free ends of the conventional bicycle crank; during the actual installation process, the transmission shaft first passes through the bottom bracket structure of the frame, and then the drive-side crank and the non-drive-side crank are installed at the left and right connection head positions for limit fixation. Finally, in order to be compatible with the width specifications of the bottom bracket, adjustment components such as preload rings and thickness adjustment washers are often used to fill the clearance play existing between the left and right cranks and the bottom bracket structure bearings, so as to ensure the centering symmetry of the left and right cranks and prevent the left and right end cranks from shaking and making abnormal noises.

[0003] However, such crank assemblies with preload rings and washers have a series of problems: First, the traditional preload rings and washers are completely exposed between the crank and the bottom bracket structure, and their installation positions are outside the crank arms; since the exposed surfaces are directly in contact with the external environment, in rainy days or when facing sandy road sections, etc., sediment and water are easily attached to the preload rings and washers; as the rider continues to ride, due to the axial shaking effect, sand grains are easily intruded into the gaps between the two fittings to form a "washer effect", forcibly enlarging the mating clearance between the crank and the bottom bracket bearing, and then gradually there will be clearance play, resulting in axial instability of the transmission shaft and shaking abnormal noises. It can be seen that the preload rings and washer structures with a completely exposed design are prone to direct contact with external pollutants during the riding process, damaging the product stability and service life. Second, since the installation positions of the left and right cranks on the transmission shaft are fixed according to the designed positions of the connection heads first, and then in order to adapt to the width specifications of the bottom bracket and ensure the centering symmetry of the left and right cranks, the left and right cranks need to independently adjust the preload rings and washer thicknesses respectively. However, this kind of assembly fine-tuning usually requires professional operators. It is cumbersome and difficult for users to assemble by themselves, and even if the assembly is completed, it is easy to produce errors and cause asymmetric installation, which will further lead to inconsistent distances between the left and right cranks and the middle bottom bracket, that is, the asymmetric left and right cranks are likely to cause significantly different forces on the left and right feet during riding, and the riding posture will shift, and over time, sports injuries will occur. Third, the installation positions of the preload rings and adjustment washers result in extremely small space for users to adjust, and the clearance adjustment is time-consuming, laborious and inconvenient.

[0004] Therefore, the existing novel crank assemblies for bicycles urgently need to be improved. Summary of the Invention

[0005] The object of the present invention is to overcome the above-mentioned defects or problems in the background art, and to provide a novel crank assembly for a bicycle, which not only has a simple structure and is easy to assemble, but also can effectively block the intrusion path of sediment and eliminate the axial fit clearance, thereby solving the defects such as poor stability and difficult maintenance caused by the complete exposure of the adjusting components in the prior art. To achieve the above object, the present invention adopts the following technical solutions:

[0006] A novel crank assembly for a bicycle, characterized in that it comprises: a transmission shaft which is inserted through the bottom bracket structure of the bicycle; a locking portion for fixedly connecting the non-driving side crank is provided at the non-driving end of the transmission shaft, and an axial screw hole is provided at the driving end of the transmission shaft; a side crank structure, including a crank arm and a compensation sleeve, an adjustment bolt, a guiding sleeve and a connecting sleeve which are respectively built in the sleeve hole of the crank arm; the compensation sleeve is sleeved on the driving end of the transmission shaft, and one end face of the compensation sleeve is used to abut against the bearing of the bottom bracket structure; the inner wall of the guiding sleeve is in threaded cooperation with the compensation sleeve and is used to drive the compensation sleeve and the connecting sleeve to axially displace; the inner wall of the connecting sleeve and the outer wall of the compensation sleeve are respectively provided with mutually adapted inclined surfaces, and the inclination directions of the inclined surfaces extend outward from the guiding sleeve towards the bottom bracket structure; wherein, the guiding sleeve rotates and its end face abuts against the end face of the connecting sleeve, so as to drive the compensation sleeve to translate and abut against the bearing surface of the bottom bracket structure, and to push the connecting sleeve to axially move under the limited state of the compensation sleeve, so that the connecting sleeve restricts the compensation sleeve from retreating in the radial and axial directions through the inclined surface; the adjustment bolt is screwed into the axial screw hole of the transmission shaft and acts on the compensation sleeve to limit the axial retreat and / or circumferential movement of the compensation sleeve.

[0007] Preferably, a tightening base sleeve is provided on a part of the compensation sleeve that protrudes out of the sleeve hole of the crank arm, and the tightening base sleeve is driven by an axial force to abut against the bearing surface of the bottom bracket structure; a ring groove is recessed in the tightening base sleeve towards the axis direction.

[0008] Preferably, the adjustment bolt and the compensation sleeve are located inside the guiding sleeve, and the adjustment bolt is located between the guiding sleeve and the compensation sleeve; a double-sided ring is provided at the free end position of the adjustment bolt away from the axial screw hole, and the double-sided ring extends outward along the radial direction of the adjustment bolt, so as to act on the guiding sleeve to abut and drive it to rotate synchronously when the adjustment bolt is reversed and retracted, so that the guiding sleeve is disengaged from the end face of the connecting sleeve.

[0009] Preferably, the double-sided ring includes a forward end face acting on the compensation sleeve and a reverse end face acting on the guiding sleeve, and the forward end face and the reverse end face are parallel to each other.

[0010] Preferably, the guiding sleeve further includes a locking ring formed on the inner wall position, the outer diameter of the double-sided ring is larger than the inner diameter of the locking ring and their axes coincide; the locking ring is used to act against the reverse end face of the double-sided ring to make the guiding sleeve move synchronously with the clearance adjusting bolt.

[0011] Preferably, the compensating sleeve includes a locking sleeve, an inclined base sleeve and the abutting base sleeve formed in sequence from left to right towards the transmission shaft; wherein, the guiding sleeve is configured to be in threaded fit with the locking sleeve; the inclined base sleeve is configured as a spline sleeve, and the inner wall of the connecting sleeve is sleeved on the inclined base sleeve and connected by splines to form an anti-rotation constraint, and their inclined surfaces cooperate with each other.

[0012] Preferably, a transition groove is recessed at the connection position between the locking sleeve and the inclined base sleeve.

[0013] Preferably, a coaxial receiving ring is further formed on the side of the connecting sleeve, and the receiving ring is located between the connecting sleeve and the five-way structure; the receiving ring corresponds to the abutting base sleeve, and its inner diameter is larger than the outer diameter of the abutting base sleeve; the receiving ring is used to cooperate with the limiting ring to constrain the chainring between the crank arm and the five-way structure and form an axial gap between the chainring and the five-way structure.

[0014] Preferably, the side crank structure further includes a cover screwed on the outside of the connecting sleeve, and the cover is located on the side away from the five-way structure; a stop ring is formed on the outer wall of the connecting sleeve, and the crank arm is sleeved on the connecting sleeve and located between the connecting sleeve and the cover to perform axial constraint and limit through the cooperation of the cover and the connecting sleeve.

[0015] Preferably, the non-driving side crank and the crank arm are respectively at equal distances from the five-way structure and are symmetrically arranged at the left and right ends of the five-way structure.

[0016] As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention provides a novel crank assembly for a bicycle, which not only has a simple structure and is easy to assemble, but also can effectively block the path of sediment intrusion and eliminate the axial fit clearance, thereby solving the defects such as poor stability and difficult maintenance caused by the complete exposure of the adjusting components in the prior art. The present invention mainly designs a side crank structure, which has many functions. First, it has the functions of resisting sediment and preventing loosening. Since the traditional preloading ring and adjusting washer are completely exposed between the crank arm and the bottom bracket structure, sediment and water flow are easy to invade the bottom bracket system through the gaps, resulting in an enlarged gap and a decrease in stability. By placing the main structures of the compensation sleeve, the gap adjusting bolt, the guiding sleeve and the connecting sleeve inside the sleeve hole of the crank arm, a hidden adjusting structure that is not exposed is formed, significantly blocking the path of sediment invading the core adjusting area. Compared with the traditional exposed design, the long-term stability is significantly improved, and the product experience is better. Second, the double limiting mechanism improves the reliability. The inclined surfaces of the connecting sleeve and the compensation sleeve adopt an inclined surface matching method, and the radial and axial forces generated thereby can effectively limit the compensation sleeve beside the bearing of the bottom bracket structure, effectively preventing the compensation sleeve from retreating axially. In this way, the first limit of the compensation sleeve is realized; secondly, the gap adjusting bolt is screwed into the axial screw hole at the driving end, and the axial displacement is directly applied to the compensation sleeve by screwing the gap adjusting bolt, so as to realize the second limit of the compensation sleeve to eliminate the axial fit clearance. Such a double limiting mechanism can greatly avoid the instability and abnormal noise of the transmission shaft caused by the loosening, backward movement and self-rotation of the compensation sleeve. Third, it is convenient to adjust. If the user needs to adjust the axial clearance to ensure centering, simply controlling the gap adjusting bolt and the guiding sleeve can perform fine adjustment by themselves, and the maintenance is convenient and very easy.

[0018] (2) In this technical solution, the tightening base sleeve is arranged to protrude from the sleeve hole of the crank arm, and a ring groove is recessed in the tightening base sleeve towards the axis direction; thus, in a riding scenario, if there are external objects, fluids such as sediment or water sprayed onto the crank assembly, these objects and fluids are not easily attached to the surface of the crank assembly but mostly will be collected into the ring groove, and with continuous riding, a centrifugal force will be generated, effectively throwing them all out of the ring groove for emptying. In this way, this product has a certain self-cleaning effect, and even if there is accumulation, there is no need to disassemble the entire crank structure. Simply spraying the ring groove with a spray gun can quickly complete the cleaning. Therefore, compared with the traditional completely exposed preloading ring and washer, the exposed area is reduced by more than 80%, and self-cleaning is achieved through the action of centrifugal force, significantly reducing the impact of sediment accumulation on the adjusting area.

[0019] (3) In this technical solution, when it is necessary to loosen and disassemble the crank arm, the disassembly efficiency is extremely high; only by controlling the adjusting bolt to reverse and retreat, the reverse end face of the double-sided ring can directly abut against the locking ring on the inner wall of the driving sleeve, driving the driving sleeve to rotate synchronously and disengage from the end face of the connecting sleeve. Without applying an additional rotational force to the driving sleeve, it will rotate synchronously following the movement. This linkage mechanism reduces the disassembly steps, eliminates the need for additional tools or step-by-step operations, and makes the entire side crank structure extremely easy to disassemble, with convenient and fast disassembly and assembly, and significantly improved maintenance efficiency.

[0020] (4) In this technical solution, the forward end face and the reverse end face of the double-sided ring are parallel, ensuring that the force transmission direction is consistent when the adjusting bolt is tightened or retreated, avoiding eccentric wear caused by end face inclination and extending the service life of the components. Secondly, the parallel end face design makes the acting forces of the adjusting bolt on the compensation sleeve and the driving sleeve evenly distributed during axial movement, avoiding the problem of local stress concentration caused by inclined plane contact and improving the adjustment stability.

[0021] (5) In this technical solution, a transition groove is recessed at the connection position between the locking nut sleeve and the inclined base sleeve. This transition groove can store air to avoid the vacuum adsorption effect during the locking process; and this design significantly reduces the disassembly resistance of the compensation sleeve and the driving sleeve, saving time and effort during maintenance and making the operation easy.

[0022] (6) In this technical solution, the receiving ring of the connecting sleeve cooperates with the limiting ring to constrain the chainring between the crank arm and the bottom bracket structure, forming an axial clearance. This design enables the chainring to have no axial movement during high-speed cycling, improving the transmission efficiency and reducing the risk of chain dropping at the same time.

[0023] (7) The non-driving side crank is fixed to the non-driving side of the transmission shaft through the locking part; in the traditional solution, it is necessary to separately adjust the preloading rings and washers on both the left and right sides to ensure centering, with complex operations and easy to generate errors. This technical solution can synchronously ensure the symmetry of the non-driving side crank and the driving side crank relative to the bottom bracket structure through a single-side adjustment design (only the driving side needs to be adjusted), reducing the installation error rate and avoiding the risk of riding posture deviation and sports injuries caused by asymmetry between the left and right cranks. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present invention;

[0026] Figure 2It is a structural schematic diagram of a state where the crank structure and the transmission shaft are detached from each other in an embodiment of the present invention;

[0027] Figure 3 It is an overall cross-sectional schematic diagram of an embodiment of the present invention;

[0028] Figure 4 for Figure 3 A partial enlarged view of

[0029] Figure 5 It is a cross-sectional schematic diagram of the crank structure and the transmission shaft in the assembly state according to an embodiment of the present invention;

[0030] Figure 6 It is an exploded schematic diagram of an embodiment of the present invention;

[0031] Figure 7 It is a schematic structural diagram of a gap adjusting bolt and a compensating sleeve according to an embodiment of the present invention.

[0032] The following are the descriptions of the reference numerals:

[0033] 1. Transmission shaft; 2. Side crank structure; 21. Crank arm; 22. Compensating sleeve; 221. Tightening base sleeve; 222. Locking screw sleeve; 223. Inclined base sleeve; 224. Transition groove; 22a. Annular groove; 23. Adjustment bolt; 231. Double-sided ring; 23a. Positive end face; 23b. Reverse end face; 24. Guide sleeve; 241. Locking ring; 25. Connecting sleeve; 251. Stop ring; 252. Receiver ring; 253. Limiting ring; 26. Cover; 3. Non-driving side crank; 4. Chainring. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are preferred embodiments of the present invention and should not be regarded as excluding other embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the claims, description and the above-mentioned drawings of the present invention, unless otherwise clearly defined, the use of terms such as "first", "second" or "third" etc. are for distinguishing different objects rather than for describing a specific order.

[0036] In the claims, description and above-mentioned drawings of the present invention, unless otherwise clearly defined, for orientation terms, such as the use of terms "center", "lateral", "longitudinal", "horizontal", "vertical", "top", "bottom", "inner", "outer", "upper", "lower", "front", "rear", "left", "right", "clockwise", "counterclockwise", etc. to indicate the orientation or positional relationship are based on the orientation and positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, so it should not be construed as limiting the specific protection scope of the present invention.

[0037] In the claims, description and above-mentioned drawings of the present invention, unless otherwise clearly defined, if the terms "fixed connection" or "fixedly connected" are used, they should be understood in a broad sense, that is, any connection method without displacement relationship and relative rotation relationship between the two, that is, including non-removable fixed connection, removable fixed connection, being integrated as a whole, and being fixed by other devices or elements.

[0038] In the claims, description and above-mentioned drawings of the present invention, if the terms "comprising", "having" and their variants are used, they are intended to mean "including but not limited to".

[0039] Please refer to Figures 1 to 7 。

[0040] The present invention provides a novel crank assembly for a bicycle.

[0041] The crank assembly includes a drive shaft 1 and a non-drive side crank 3 and a side crank structure 2 provided at the left and right ends of the drive shaft 1; wherein, it includes:

[0042] Refer to Figures 1 to 3

[0043] The drive shaft 1 is a hollow drive shaft 1 with a hollow interior; it penetrates through the bottom bracket structure of the bicycle and is connected by insertion. Both shaft ends (non-drive end, drive end) of the drive shaft 1 protrude from the bottom bracket structure (not shown in the figure) and are located on its left and right sides; a locking portion for fixedly connecting the non-drive side crank 3 is provided at the non-drive end of the drive shaft 1, and the locking portion is mainly a spline connector or a keyway, etc. The non-drive side crank 3 is sleeved on the locking portion for pre-positioning, and then the non-drive side crank 3 is completely fixed on the drive shaft 1 by fixing methods such as interference fit, external gluing or bolt tightening, etc., so that the axial movement and circumferential rotation of the non-drive side crank 3 are completely locked and limited, and thus it can only rotate synchronously with the drive shaft 1; and an axial screw hole is provided at the drive end of the drive shaft 1, the axial screw hole extends along the axis of the drive shaft 1, and its axis coincides with the axis of the drive shaft 1.

[0044] Refer to Figures 3 to 7 ,

[0045] A side crank structure 2, which is mainly arranged at the driving end of the transmission shaft 1; the whole side crank structure 2 includes a crank arm 21 and a compensation sleeve 22, an adjusting bolt 23, a guiding sleeve 24 and a connecting sleeve 25 which are respectively arranged in the sleeve hole of the crank arm 21, that is, the compensation sleeve 22, the adjusting bolt 23, the guiding sleeve 24 and the connecting sleeve 25 are all located in the sleeve hole of the crank arm 21 to form a non-exposed hidden adjustment structure, so as to block the path of sediment invading the core adjustment area, and it is less likely to be affected by external factors such as sediment and water, improving the long-term stability.

[0046] In this embodiment, the compensation sleeve 22 is sleeved on the driving end of the transmission shaft 1, and one end face of the compensation sleeve 22 is used to abut against the bearing of the bottom bracket structure (in the prior art, two bearings, left and right, are installed on both sides inside the bottom bracket structure to ensure that when riding, the crank bears the alternating pedaling forces from both left and right sides. The two bearings can evenly distribute the radial and axial loads, avoid overloading of a single bearing, and reduce the risk of wear and deformation). The guiding sleeve 24 is in threaded fit with the compensation sleeve 22 (the inner wall of the guiding sleeve 24 and the outer wall of the compensation sleeve 22 have threads), and is used to drive the axial displacement of the compensation sleeve 22 and the connecting sleeve 25; the inner wall of the connecting sleeve 25 and the outer wall of the compensation sleeve 22 are respectively provided with mutually adapted inclined surfaces, and the inclined directions of the inclined surfaces extend outward from the guiding sleeve 24 towards the bottom bracket structure.

[0047] Specifically, in this embodiment, the guiding sleeve 24 moves axially along the compensation sleeve 22 by rotating on the compensation sleeve 22, and its end face abuts against the end face of the connecting sleeve 25; as it continues to move, the connecting sleeve 25 comes into contact with the inclined surface of the compensation sleeve 22 to drive the compensation sleeve 22 to translate and abut against the bearing surface of the bottom bracket structure. At this time, in the limited state where the compensation sleeve 22 is held, the guiding sleeve 24 continues to rotate to push the connecting sleeve 25 to move axially. The inclined surface of the connecting sleeve 25 and the inclined surface of the compensation sleeve 22 continue to interact with each other, and the inner wall of the connecting sleeve 25 will be affected by the outer wall of the compensation sleeve 22 and radially deform and expand to generate a radial binding force, realizing that the inclined surface of the connecting sleeve 25 restricts and inhibits the compensation sleeve 22 from retracting in the radial and axial directions, and completing the first constraint on the compensation sleeve 22 (radial and axial constraints).

[0048] In this embodiment, the adjusting bolt 23 is screwed into the axial screw hole of the transmission shaft 1, and it moves axially by screwing and acts on the compensation sleeve 22 to further limit the axial retraction and circumferential movement of the compensation sleeve 22. The adjusting bolt 23 provides a second limit (axial tightening), realizing a double limit mechanism to prevent the compensation sleeve 22 from retracting and rotating.

[0049] In this embodiment, the clearance adjusting bolt 23 and the compensation sleeve 22 are located inside the guiding sleeve 24, and the clearance adjusting bolt 23 is located between the guiding sleeve 24 and the compensation sleeve 22; at the free end position of the clearance adjusting bolt 23 away from the axial screw hole, there is a double-sided ring 231, and the double-sided ring 231 includes a forward end face 23a acting on the compensation sleeve 22 and a reverse end face 23b acting on the guiding sleeve 24, and the forward end face 23a and the reverse end face 23b are parallel to each other. Moreover, the double-sided ring 231 extends outward along the radial direction of the clearance adjusting bolt 23 for when the clearance adjusting bolt 23 is reversed and retracted, the reverse end face 23b acts on and tightly abuts against the guiding sleeve 24 to drive it to rotate synchronously, so that the guiding sleeve 24 rotates and retracts synchronously with the compensation sleeve 22, and further the guiding sleeve 24 disengages from the end face of the connecting sleeve 25, loosening the inclined surface fit and canceling the axial and radial binding forces.

[0050] In this embodiment, the guiding sleeve 24 further includes a locking ring 241 formed at the inner wall position, the outer diameter of the double-sided ring 231 is larger than the inner diameter of the locking ring 241 and their axes coincide; the locking ring 241 is used to act and tightly abut against the reverse end face 23b of the double-sided ring 231 so that the guiding sleeve 24 moves synchronously with the clearance adjusting bolt 23. Secondly, the locking ring 241 can also be adapted to a special tool, that is, by rotating the special tool, the guiding sleeve 24 can be driven to rotate synchronously.

[0051] In this embodiment, the compensation sleeve 22 includes a locking sleeve 222, an inclined base sleeve 223 and a pressing base sleeve 221 integrally formed and sequentially formed from left to right towards the transmission shaft 1, the inclined base sleeve 223 is located between the pressing base sleeve 221 and the locking base sleeve, and the pressing base sleeve 221 is close to the five-way structure; wherein, the pressing base sleeve 221 is arranged to expose the sleeve hole of the crank arm 21, and the pressing base sleeve 221 belongs to a partial structure of the compensation sleeve 22; the pressing base sleeve 221 is driven by an axial force to abut against the bearing surface of the five-way structure; the pressing base sleeve 221 is concavely provided with an annular groove 22a towards the axial direction. In a riding scenario, if external objects such as sediment or water, fluids, etc. are sprayed onto the crank assembly, these objects and fluids are not easily attached to the surface of the crank assembly and most will be collected into the annular groove 22a, and with continuous riding, a centrifugal force will be generated, effectively throwing them all out of the annular groove 22a for evacuation. Thus, this product achieves a certain self-cleaning effect through the annular groove 22a, and even if there is a buildup and it cannot be cleaned, simply spraying the annular groove 22a with a spray gun can quickly complete the cleaning.

[0052] In this embodiment, the guiding sleeve 24 is configured to be threadedly engaged with the locking sleeve 222; the inclined base sleeve 223 is configured as a spline sleeve, and the inner wall of the connecting sleeve 25 is sleeved on the inclined base sleeve 223 for spline connection to form an anti-rotation constraint, and their inclined surfaces cooperate with each other.

[0053] In this embodiment, a transition groove 224 is recessed at the connection position between the locking sleeve 222 and the inclined base sleeve 223. The transition groove 224 can store a certain amount of air to avoid the vacuum adsorption effect during the locking process, thereby preventing resistance from occurring when the disassembly compensation sleeve 22 and the guiding sleeve 24 are removed.

[0054] In this embodiment, the distances from the non-driving side crank 3 and the crank arm 21 to the bearings of the bottom bracket structure are equal respectively, so as to be symmetrically arranged at the left and right ends of the bottom bracket structure. The non-driving side crank 3 is installed on the locking portion of the transmission shaft 1 and cannot move, so that the clearance between the non-driving side crank 3 and the bottom bracket structure always remains at a certain value. In this way, as long as the clearance between the crank arm 21 and the bearings of the bottom bracket structure is adjusted unilaterally, the crank arm 21 and the non-driving side crank 3 can remain symmetrical with the bottom bracket structure as the center. And the side crank structure 2 of this embodiment is a single-sided adjustment structure. When the clearance needs to be reduced in daily use, the user only needs to simply fine-tune the clearance adjusting bolt 23, and it is very easy to ensure the symmetry of the two side cranks. The daily fine-tuning function of the clearance adjusting bolt 23 is applicable to the one-way reduction of the axial clearance. The user can easily control the rotation of the clearance adjusting bolt 23 to achieve neutral fine-tuning, which is simple and fast; and when the clearance needs to be increased in daily use, the user only needs to control the clearance adjusting bolt and the guiding sleeve to rotate in the opposite direction to re-adjust the initial mating position between the guiding sleeve and the compensation sleeve, and the adjustment can be completed; the neutral adjustment does not require professional operation and is not restricted by space obstacles.

[0055] In this embodiment, a part of the connecting sleeve protrudes out of the sleeve hole of the crank arm 21, and this protruding part is the receiving ring 252, on the side of the receiving ring 252 close to the bottom bracket structure; the receiving ring 252 is used for sleeving and placing the chainring 4. The diameter of the receiving ring 252 is larger than that of the abutting base sleeve 221, and the inner wall surface of the receiving ring 252 corresponds to the outer wall surface of the abutting base sleeve 221; the inner wall surface of the receiving ring 252 is configured as a threaded wall. When the chainring 4 is placed on the receiving ring 252, a limiting ring 253 is sleeved on the transmission shaft 1 and forms a threaded connection with the threaded wall of the receiving ring 252. As the thread is locked, the limiting ring 253 presses and limits the chainring 4, so as to constrain the chainring 4 between the crank arm 21 and the bottom bracket structure, and form an axial clearance between the chainring 4 and the bottom bracket structure to ensure that the chainring 4 will not contact the bottom bracket structure. In this embodiment, although the limiting ring 253 is also located between the transmission shaft 1 and the bottom bracket structure, after the locking is completed, the limiting ring 253 will never contact the bottom bracket structure including the bearings therein, and only the abutting base sleeve 221 will contact the bearings.

[0056] In this embodiment, the side crank structure 2 further includes a cover 26 screwed to the outside of the connecting sleeve 25, and the cover 26 is located on the side away from the bottom bracket structure; a stop ring 251 is formed on the outer wall of the connecting sleeve 25, and the crank arm 21 is sleeved on the connecting sleeve 25 and located between the connecting sleeve 25 and the cover 26, so as to perform axial restraint and limit through the cooperation of the cover 26 and the connecting sleeve 25.

[0057] In this embodiment, the outer diameter of the cover 26 has an external thread, and an internal thread is formed on the inner wall of the other side of the connecting sleeve 25 away from the bottom bracket structure. Therefore, during installation, the cover 26 is sleeved on the guide sleeve 24 and screwed to the connecting sleeve 25, and can also provide a certain limit to the guide sleeve 24. In this way, when the guide sleeve 24 becomes loose and moves backward, it can be restrained by the cover 26. After the cover 26 is locked, it will also abut against the crank arm 21 and cooperate with the stop ring 251 to lock the crank arm 21 and the connecting sleeve 25, preventing the crank arm 21 from detaching from the connecting sleeve 25.

[0058] In this embodiment, the driving-side free end of the transmission shaft 1, the inner wall surface of the compensation sleeve 22, the outer wall surface of the inclined base sleeve 223 of the compensation sleeve 22, the inner wall surface of the guide sleeve 24, and the inner wall surface of the outer wall surface of the guide sleeve 24 and the crank arm 21 are all configured in a spline shape. In this way, after the installation of each component is completed, the circumferential rotation will be restricted; therefore, as long as the crank arm 21 rotates, it will drive each component to rotate synchronously.

[0059] The working principle and installation process of the present invention:

[0060] During installation,

[0061] First, install the non-driving-side crank 3 on the locking portion of the non-driving side of the transmission shaft 1; see Figure 2 , and then, set the entire side crank structure 2 beside the driving side of the transmission shaft 1 and prepare for installation.

[0062] Second, see Figures 2 to 4 , first move the entire side crank structure 2 close to the driving side of the transmission shaft 1, and then control the crank arm 21 to be sleeved on the driving side, so that the compensation sleeve 22 is sleeved and connected to the transmission shaft 1. At this time, the entire side crank structure 2 is pre-positioned on the transmission shaft 1;

[0063] Third, see Figure 4, first, act on the locking ring 241 of the guiding sleeve 24 through a tool, and rotate the locking ring 241 to drive the inner wall of the guiding sleeve 24 to be screwed with the locking sleeve 222 of the compensation sleeve 22; as the rotational force continues to be applied, the guiding sleeve 24 moves axially along the compensation sleeve 22, and its end face abuts against the end face of the connecting sleeve 25, driving the inclined surface of the inner wall of the connecting sleeve 25 to contact the inclined surface of the inclined base sleeve 223 of the compensation sleeve 22, so as to drive the compensation sleeve 22 to translate until the abutting base sleeve 221 of the compensation sleeve 22 abuts against the bearing surface of the five-way structure (not shown in the figure) for positioning. At this time, the compensation sleeve 22 is in a limited state;

[0064] Fourth, continue to apply a rotational force to the locking ring 241. The force exerted by the guiding sleeve 24 on the connecting sleeve 25 gradually increases. The guiding sleeve 24 pushes the connecting sleeve 25 to move axially, so that the inclined surface of the connecting sleeve 25 and the inclined surface of the inclined base sleeve 223 continue to interact with each other. As a result, the inner wall of the connecting sleeve 25 is radially deformed and expanded under the influence of the outer wall of the compensation sleeve 22 to generate a radial binding force, realizing the radial and axial limitation and suppression of the compensation sleeve 22 from retracting and rotating, and completing the first constraint on the compensation sleeve 22 (radial and axial constraints), that is, the inclined base sleeve 223 of the compensation sleeve 22 is simultaneously subjected to a radial force and an axial force;

[0065] Fifth, act on the adjusting bolt 23 through a tool; rotate the tool to control the rotation of the adjusting bolt 23, and the adjusting bolt 23 starts to move along the axial direction of the transmission shaft 1 until the positive end face 23a of the double-sided ring 231 of the adjusting bolt 23 acts on the locking sleeve 222 of the compensation sleeve 22, so that the compensation sleeve 22 is secondarily subjected to an axial binding force, that is, the locking sleeve 222 of the compensation sleeve 22 is subjected to an axial force, completing the double limiting and suppression of the whole compensation sleeve 22, effectively preventing the compensation sleeve 22 from retracting and circumferentially moving from the transmission shaft 1. At this time, the crank arm 21 is fixed to the driving side of the transmission shaft 1 and maintains a certain gap relative to the five-way structure.

[0066] When it is necessary to loosen and disassemble the crank arm 21, only the adjusting bolt 23 needs to be loosened. The adjusting bolt 23 undergoes axial displacement, and the reverse end face 23b of its double-sided ring 231 abuts against the driving sleeve 24. The driving sleeve 24 does not require a rotational force and will rotate synchronously under the action of the adjusting bolt 23. In this way, both the driving sleeve 24 and the adjusting bolt 23 are finally completely loosened, and the crank arm 21 can be disassembled; only by rotating the adjusting bolt 23 can rapid disassembly be achieved, without loosening the adjusting bolt 23 and the driving sleeve 24 one by one. Therefore, the present invention has low cost and can be quickly assembled. By replacing the traditional preloading ring and adjusting washer with the compensation sleeve 22, the path of sediment intrusion is blocked and the axial fit clearance is eliminated, solving the problems caused by the traditional preloading ring and thickness adjusting washer used in the existing crank assembly. The present invention not only reduces the manufacturing cost and simplifies the assembly process, but also effectively blocks the path of sediment intrusion and eliminates the axial fit clearance, thereby solving the defects such as poor stability and difficult maintenance caused by the complete exposure of the adjusting components in the prior art. The present invention mainly designs a side crank structure 2, which has many functions. First, it has the functions of resisting sediment and preventing loosening. Since the traditional preloading ring and adjusting washer are completely exposed between the crank arm 21 and the bottom bracket structure (not shown in the figure), sediment and water flow are easy to invade the bottom bracket system through the gaps, resulting in an enlarged gap and a decrease in stability. By placing the main structures of the compensation sleeve 22, adjusting bolt 23, driving sleeve 24 and connecting sleeve 25 inside the sleeve hole of the crank arm 21 to form a non-exposed hidden adjustment structure, the path of sediment intrusion into the core adjustment area is significantly blocked. Compared with the traditional exposed design, the long-term stability is significantly improved and the product experience is better. Second, the double limiting mechanism improves the reliability. The inclined surfaces of the connecting sleeve 25 and the compensation sleeve 22 adopt an inclined surface matching method, and the radial and axial forces generated in this way can effectively limit the compensation sleeve 22 beside the bottom bracket structure bearing, effectively preventing the compensation sleeve 22 from retreating axially. In this way, the first limit of the compensation sleeve 22 is achieved; secondly, the adjusting bolt 23 is screwed into the axial screw hole at the driving end, and the axial displacement is realized by screwing the adjusting bolt 23 to directly abut against the compensation sleeve 22. In this way, the second limit of the compensation sleeve 22 is achieved to eliminate the axial fit clearance. In this way, the double limiting mechanism can greatly avoid the instability and abnormal noise of the transmission shaft caused by the loosening, backward movement and self-rotation of the compensation sleeve 22. Third, it is convenient to adjust. If the user needs to adjust the axial clearance to ensure centering, simply controlling the adjusting bolt 22 and the driving sleeve 24 can perform self-adjustment, which is convenient and very easy to maintain.

[0067] The description of the above-mentioned specification and embodiments is used to explain the protection scope of the present invention, but does not constitute a limitation on the protection scope of the present invention. Modifications, equivalent replacements or other improvements to the embodiments of the present invention or some of its technical features that can be obtained by those of ordinary skill in the art through logical analysis, reasoning or limited experiments in combination with common general knowledge, ordinary technical knowledge in this field and / or the prior art shall be included within the protection scope of the present invention.

Claims

1. A new crank assembly for a bicycle, characterized in that: include: A transmission shaft is inserted through the five-way structure of the bicycle; the non-driving end of the transmission shaft is provided with a locking portion for fixing the non-driving side crank, and the driving end of the transmission shaft is provided with an axial screw hole; The side crank structure comprises a crank arm and a compensation sleeve, a clearance adjustment bolt, a guide sleeve and a connecting sleeve respectively built into the sleeve holes of the crank arm; the compensation sleeve is sleeved on the driving end of the transmission shaft, and one end face of the compensation sleeve is used to support the bearing of the five-way structure; the inner wall of the guide sleeve is threadedly matched with the compensation sleeve, and is used to drive the axial displacement of the compensation sleeve and the connecting sleeve; the inner wall of the connecting sleeve and the outer wall of the compensation sleeve are respectively provided with mutually matching inclined surfaces, and the inclination direction of each inclined surface extends outward from the guide sleeve toward the five-way structure; wherein the guide sleeve rotates and its end face abuts against the end face of the connecting sleeve, so as to drive the compensation sleeve to translate and support the bearing surface of the five-way structure, and to push the connecting sleeve to move axially in the limiting state of the compensation sleeve, so that the connecting sleeve limits the retreat of the compensation sleeve in the radial and axial directions through the inclined surface; The gap adjustment bolt is threadedly connected to the axial screw hole of the transmission shaft and acts on the compensation sleeve to limit the axial retreat and / or circumferential movement of the compensation sleeve.

2. A novel crank assembly for a bicycle as claimed in claim 1, characterized in that: The sleeve hole of the crank arm exposed outside the compensation sleeve has a tightening base sleeve, and the tightening base sleeve is driven by the axial force to support the bearing surface of the five-way structure; the tightening base sleeve is concavely provided with an annular groove toward the axial direction.

3. A new crank assembly for a bicycle as claimed in claim 2, characterized in that: The adjusting bolt and the compensating sleeve are located on the inner side of the guide sleeve, and the adjusting bolt is located between the guide sleeve and the compensating sleeve; the free end of the adjusting bolt away from the axial screw hole has a double-sided ring, and the double-sided ring extends outward along the radial direction of the adjusting bolt, so that when the adjusting bolt is reversed and retreated, it acts on the guide sleeve to tighten and drive it to rotate synchronously, so that the guide sleeve is separated from the end face of the connecting sleeve.

4. A new crank assembly for a bicycle as claimed in claim 3, characterized in that: The double-sided ring comprises a positive end face acting on the compensation sleeve and a negative end face acting on the guide sleeve, and the positive end face and the negative end face are parallel.

5. A novel crank assembly for a bicycle as claimed in claim 4, characterized in that: The guide sleeve also includes a locking ring formed on the inner wall, the outer diameter of the double-sided ring is larger than the inner diameter of the locking ring and the axes of the two coincide with each other; the locking ring is used to act and tighten with the reverse end face of the double-sided ring so that the guide sleeve and the gap adjustment bolt move synchronously.

6. A new crank assembly for a bicycle as claimed in claim 2, characterized in that: The compensating sleeve includes a locking nut, an inclined base sleeve and a tightening base sleeve which are formed in sequence from left to right toward the transmission shaft; wherein the guide sleeve is arranged on the locking nut and threadedly cooperates with each other; the inclined base sleeve is configured as a spline sleeve, and the inner wall of the connecting sleeve is sleeved on the inclined base sleeve and splined to form a rotation-stopping constraint, and the inclined surfaces of the two cooperate with each other.

7. A new crank assembly for a bicycle as claimed in claim 6, characterized in that: A transition groove is formed at a connection position between the locking screw sleeve and the inclined base sleeve.

8. A novel crank assembly for a bicycle as claimed in claim 6, characterized in that: A coaxial receiving ring is also formed on the side of the connecting sleeve, and the receiving ring is located between the connecting sleeve and the five-way structure; the receiving ring corresponds to the abutment base sleeve, and its inner diameter is larger than the outer diameter of the abutment base sleeve; the receiving ring is used to cooperate with a limiting ring to constrain the chainring between the crank arm and the five-way structure, and to form an axial gap between the chainring and the five-way structure.

9. A novel crank assembly for a bicycle as claimed in claim 1, characterized in that: The side crank structure also includes a cover screwed to the outside of the connecting sleeve, and the cover is located on the side away from the five-way structure; a stop ring is formed on the outer wall of the connecting sleeve, and the crank arm is sleeved on the connecting sleeve and is located between the connecting sleeve and the cover, so as to cooperate with the connecting sleeve to perform axial constraint and limitation.

10. A novel crank assembly for a bicycle as claimed in claim 1, characterized in that: The non-driving side crank and the crank arm are equidistant from the five-way structure so as to be symmetrically arranged at the left and right ends of the five-way structure.

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