Thick and thin fluted disc

Abstract

A thick and thin fluted disc comprises a disc body unit, a thin tooth unit and a thick tooth unit. The thin tooth unit comprises a plurality of thin convex teeth, a plurality of front side tooth bottoms and a plurality of rear side tooth bottoms which are arranged among the thin convex teeth in a staggered mode, a thin tooth back face flush with one disc body back face of the disc body unit, and a thin tooth front face. Each thin convex tooth is provided with a driving surface, a slipping surface and a tooth top surface, wherein the slipping surface and the driving surface are asymmetrical in shape. Each rear tooth bottom is provided with a first chamfer connected with the front face of the thin tooth and a second chamfer connected with the back face of the thin tooth. The thick tooth unit comprises a plurality of thick convex teeth and a plurality of grooves connected among the thick convex teeth, each thick convex tooth is integrally formed on the thin tooth front surface of the thin convex tooth behind the rear side tooth bottom, the width of the thick convex tooth is equal to the width of the groove, and the thickness of the thick convex tooth accounts for 30-50% of the thickness of the thin convex tooth. When a chain is driven, the guiding and correcting effects can be achieved.

Description

Technical Field

[0001] The present invention relates to a chainring, and in particular to a thick-thin chainring used for bicycles or motorcycles. Background Art

[0002] A conventional transmission system for a bicycle or motorcycle typically includes at least two sprockets spaced apart from each other, and a chain meshed with the sprockets. Each sprocket includes a plurality of protruding teeth formed on its periphery. The chain comprises a plurality of inner chain plates, a plurality of outer chain plates, a plurality of chain rollers disposed between the inner chain plates, and a plurality of chain axles connecting the inner and outer chain plates. The inner chain plates and the chain rollers define a plurality of meshing spaces.

[0003] During transmission, the sprocket rotates in a transmission direction to engage and drive the chain. However, since the sprocket lacks any guide design, the protruding teeth can easily collide with or even get stuck on the ends of the inner link plates when engaging with the meshing space, causing unusual noises and even preventing smooth engagement. Therefore, improvements are needed. Summary of the Invention

[0004] An object of the present invention is to provide a thick-thin gear disc that can overcome at least one disadvantage of the prior art.

[0005] The thick-thin toothed disc of the present invention rotates in a transmission direction and comprises a disc body unit, a thin toothed unit and a thick toothed unit.

[0006] The disc unit includes a disc back surface and a disc front surface which are spaced apart from each other.

[0007] The thin-tooth unit is arranged along the periphery of the disk unit and includes a plurality of thin convex teeth, a plurality of front tooth bottoms and a plurality of rear tooth bottoms that are staggered and connected between the thin convex teeth, a thin tooth back side that is flush with the back side of the disk body and is located on the same plane, and a thin tooth front side relative to the thin tooth back side. Each of the thin convex teeth has a driving surface along the transmission direction, a slip surface opposite to the transmission direction, and a tooth top surface located on the top side and connecting the driving surface and the slip surface. The driving surface has a front fillet portion that is smoothly connected to the tooth top surface. The shapes of the driving surface and the slip surface are asymmetrical. Each of the rear tooth bottoms has a first chamfer connected to the thin tooth front side, and a second chamfer connected to the thin tooth back side and corresponding to the first chamfer.

[0008] The thick tooth unit is arranged along the periphery of the disc unit and includes several thick convex teeth and several grooves connected between the thick convex teeth. Each of the thick convex teeth is arranged on the thin convex tooth behind the rear tooth bottom and is formed on the thin tooth front face of the thin tooth unit. The width of the thick convex tooth is equal to the width of the groove, and the thickness of each of the thick convex teeth accounts for 30 to 50% of the thickness of the thin convex tooth.

[0009] Furthermore, the thick-tooth unit further includes a thick-tooth front surface that is flush with the front surface of the disc body and located on the same plane, and the distance between the thick-tooth front surface and the thin-tooth front surface is equal to the width of the groove.

[0010] Furthermore, the radius of the front rounded corner of the driving surface is 6 to 14 mm.

[0011] Furthermore, the angle of the first chamfer is 15° to 40°, and the angle of the second chamfer is 15° to 40°.

[0012] Furthermore, the thick protruding tooth has a top edge, which is lower than the tooth top surface of the thin protruding tooth and extends in an inclined and decreasing manner toward the tooth top surface.

[0013] Furthermore, the slip surface has a rear fillet portion smoothly connected to the tooth top surface, and the radius of the rear fillet portion is 2 to 6 mm.

[0014] Furthermore, the slip surface is an inclined straight surface, which is gradually extended from the tooth top surface toward the rear tooth bottom.

[0015] Furthermore, a line connecting the centers of two adjacent front tooth bottoms and the rear tooth bottoms is defined as a pitch diameter, and an angle between the slip surface and the pitch diameter is 45° to 55°.

[0016] Furthermore, the included angle between the slip surface and the pitch diameter is 48° to 54°.

[0017] Furthermore, the driving surface has a limiting protrusion connected to the rear tooth bottom or the front tooth bottom and protruding toward the transmission direction.

[0018] The effect of the present invention is that the above-mentioned design can increase the stability of engagement with the chain, thereby improving transmission efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features and effects of the present invention will be clearly presented in the embodiments with reference to the accompanying drawings, in which:

[0020] Figure 1 is a perspective view illustrating a first embodiment of the thick-thin gear wheel of the present invention;

[0021] Figure 2 is an incomplete enlarged perspective view illustrating the first embodiment;

[0022] Figure 3 is an incomplete enlarged front view illustrating the first embodiment;

[0023] Figure 4 is an incomplete enlarged back view illustrating the first embodiment;

[0024] Figure 5 It is along Figure 3 A sectional view taken along line VV in FIG.

[0025] Figure 6 is an incomplete exploded cross-sectional view illustrating a state in which the first embodiment is engaged with a chain;

[0026] Figure 7 is an incomplete enlarged perspective view illustrating a second embodiment of the thick-thin gear wheel of the present invention; and

[0027] Figure 8 It is an incomplete enlarged front view illustrating the second embodiment. DETAILED DESCRIPTION

[0028] Before the present invention is described in detail, it should be noted that similar components are denoted by the same reference numerals in the following description.

[0029] See Figure 1 A first embodiment of the thick-thin chainring of the present invention is applied to a transmission system of a bicycle or motorcycle, and can rotate about an axis 10 in a transmission direction 11. The thick-thin chainring includes a plate body unit 2, a thin tooth unit 3, and a thick tooth unit 4.

[0030] See Figures 2 to 5 The disk unit 2 is generally in the shape of a circular flat plate, and includes a disk back 21 and a disk front 22 spaced apart from each other.

[0031] The thin tooth unit 3 is arranged along the periphery of the disk unit 2 and includes a plurality of thin protruding teeth 31 arranged at equal angles, a plurality of front tooth bottoms 32 and a plurality of rear tooth bottoms 33 arranged in an alternating manner and connected between the thin protruding teeth 31, a thin tooth back surface 35 located flush with the back surface 21 of the disk body and on the same plane, and a thin tooth front surface 36 opposite to the thin tooth back surface 35.

[0032] Each thin tooth 31 has a driving surface 311 oriented along the transmission direction 11, a run-off surface 312 oriented opposite the transmission direction 11 and asymmetrically shaped relative to the driving surface 311, a tooth top surface 313 located on the top side and connecting the driving surface 311 and the run-off surface 312, a tooth tip back surface 314 extending from one curved edge of the tooth top surface 313 to the thin tooth back surface 35, and a tooth tip front surface 315 extending from another curved edge of the tooth top surface 313 to the thin tooth front surface 36. The driving surface 311 has a front fillet 316 smoothly connected to the tooth top surface 313, with a radius of approximately 6 to 14 mm. The run-off surface 312 has a rear fillet 317 smoothly connected to the tooth top surface 313, with a radius of approximately 2 to 6 mm. The front tooth bottom 32 is located in front of the thin protruding tooth 31 along the transmission direction 11, while the opposite side is the rear tooth bottom 33. Each rear tooth bottom 33 has a first chamfer 331 connected to the thin tooth front face 36 and a second chamfer 332 connected to the thin tooth back face 35 and corresponding to the first chamfer 331. The angles of the first chamfer 331 and the second chamfer 332 are each approximately 15° to 45°, preferably 15° to 40°.

[0033] The thick tooth unit 4 is arranged along the periphery of the disc unit 2 and comprises a plurality of thick protruding teeth 41 arranged at equal angles, a plurality of thick tooth bases 42 connecting the thick protruding teeth 41, a plurality of grooves 43 defined by the thick protruding teeth 41 and the thick tooth bases 42, and a thick tooth front face 44 flush with the disc front face 22. Each thick protruding tooth 41 is positioned on a thin protruding tooth 31 behind the rear tooth base 33 and is integrally formed with the thin tooth front face 36. Each thick protruding tooth 41 has a top edge 411 that is lower than the tooth top face 313 of the thin protruding tooth 31. The width of the top edge 411 decreases gradually toward the tooth top face 313 and smoothly connects to the tooth tip front face 315. The thickness of the thick protruding tooth 41, viewed along the transmission direction 11, accounts for 30-50% of the thickness of the thin protruding tooth 31. Viewed along the axis 10 , the width of the thick protruding tooth 41 is equal to the width of the groove 43 , that is, the distance between the thick tooth front face 44 and the thin tooth front face 36 is equal to the width of the groove 43 .

[0034] See Figure 2 、 Figure 5 and Figure 6During use, the thick and thin toothed disc rotates along the transmission direction 11, adapted to engage and drive a chain 9. The chain 9 comprises a plurality of inner chain links 91 and a plurality of outer chain links 92, which are interlaced and pivotally connected. Each inner chain link 91 has two parallel inner chain plates 911 and two chain rollers 912 spaced apart and disposed between the inner chain plates 911. Each inner chain plate 911 has two inclined guides 913 formed on the inner sides of both ends. Each outer chain link 92 has two parallel outer chain plates 921, which are staggered and disposed between the outer sides of the two inner chain links 91, and two chain shafts 922 spaced apart and serially connecting the outer chain plates 921 and the inner chain plates 911. A meshing space 93 is defined between the inner chain plates 911 and the chain rollers 912.

[0035] When the thick-thin sprocket is in operation, the thin convex teeth 31 and the thick convex teeth 41 are inserted into the meshing space 93. When inserted, the first chamfer 331 and the second chamfer 332 can be used to contact the corresponding inclined guide portion 913 of the inner chain plate 911, thereby guiding and engaging in advance to avoid the chain 9 from deviating and causing wear, thereby reducing abnormal noise during engagement. In addition, the thick convex teeth 41 will also touch the inner side of the corresponding outer chain plate 921 in advance, guiding the chain 9 in advance, and improving the engagement strength and stability, which not only avoids the chain from falling off, but also makes the transmission smoother.

[0036] See Figure 7 and Figure 8 The structure of a second embodiment of the thick-thin toothed disc of the present invention is substantially the same as that of the first embodiment, with the difference being that the driving surface 311 of each thin tooth 31 has a stopper protrusion 318 connected to the rear tooth bottom 33 or the front tooth bottom 32 and protruding in the transmission direction 11. The stopper protrusion 318 is designed to preemptively contact the chain roller 912 during engagement and guide the chain roller 912 to the corresponding front tooth bottom 32 or rear tooth bottom 33. This effectively shortens the impact and running-in during initial engagement with the chain roller 912, reducing friction, lowering noise, and extending service life. Furthermore, during transmission, the drive roller 912 is more firmly engaged, effectively achieving labor-saving transmission efficiency.

[0037] Furthermore, the slip surface 312 of the second embodiment is an inclined straight surface, extending gradually from the tooth top surface 313 toward the rear tooth bottom 33. The line connecting the centers O of two adjacent front tooth bottoms 32 and rear tooth bottoms 33 is defined as a pitch diameter P. The angle θ between the slip surface 312 and the pitch diameter P is 45° to 55°, preferably 48° to 54°. The angled design of the slip surface 312 not only creates a larger space for the chain roller 912 to slide smoothly, but also saves material, achieving a lightweight design.

[0038] In summary, the design of the thick and thin sprockets of the present invention can have a guiding and correcting effect, can improve the stability of engagement with the chain 9, and can reduce friction noise and improve transmission efficiency, thus truly achieving the purpose of the present invention.

[0039] However, the above description is merely an embodiment of the present invention and should not be used to limit the scope of implementation of the present invention. All simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still within the scope of the patent of the present invention.

Claims

1. A thick and thin toothed disc, rotating in a transmission direction, and comprising: A tray unit, comprising a tray back and a tray front spaced apart, characterized in that ； A thin tooth unit is arranged along the periphery of the disc unit and includes a plurality of thin convex teeth, a plurality of front tooth bottoms and a plurality of rear tooth bottoms arranged in a staggered manner and connected between the thin convex teeth, a thin tooth back surface located flush with the back surface of the disc body and on the same plane, and a thin tooth front surface relative to the thin tooth back surface, the thin convex teeth have a driving surface along the transmission direction, a slip surface opposite to the transmission direction, and a tooth top surface located on the top side and connecting the driving surface and the slip surface, the driving surface has a front fillet portion smoothly connected to the tooth top surface, the driving surface and the slip surface are asymmetrical in shape, the rear tooth bottom has a first chamfer connected to the thin tooth front surface, and a second chamfer connected to the thin tooth back surface and corresponding to the first chamfer; and A thick tooth unit is arranged along the periphery of the disc unit and includes several thick convex teeth and several grooves connected between the thick convex teeth. The thick convex teeth are arranged on the thin convex teeth behind the rear side tooth bottom and are formed on the thin tooth front face of the thin tooth unit. The width of the thick convex teeth is equal to the width of the groove, and the thickness of the thick convex teeth accounts for 30 to 50% of the thickness of the thin convex teeth.

2. The thick and thin toothed disc according to claim 1, characterized in that: The thick tooth unit further comprises a thick tooth front face which is flush with the front face of the disc body and is located on the same plane. The distance between the thick tooth front face and the thin tooth front face is equal to the width of the groove.

3. The thick and thin toothed disc according to claim 1, characterized in that: The radius of the front rounded corner of the driving surface is 6 to 14 mm.

4. The thick and thin toothed disc according to claim 1, characterized in that: The angle of the first chamfer is 15° to 40°, and the angle of the second chamfer is 15° to 40°.

5. The thick and thin toothed disc according to claim 1, characterized in that: The thick protruding tooth has a top edge, which is lower than the tooth top surface of the thin protruding tooth and extends obliquely and gradually toward the tooth top surface.

6. The thick-thin toothed disc according to claim 1 or 3, characterized in that: The slip surface has a rear fillet portion smoothly connected to the tooth top surface, and the radius of the rear fillet portion is 2-6 mm.

7. The thick-thin toothed disc according to claim 1, characterized in that: The slip surface is an inclined straight surface, which is gradually extended from the tooth top surface toward the rear tooth bottom.

8. The thick-thin toothed disc according to claim 7, characterized in that: A line connecting the centers of two adjacent front tooth bottoms and the rear tooth bottoms is defined as a pitch diameter, and an angle between the slip surface and the pitch diameter is 45° to 55°.

9. The thick-thin toothed disc according to claim 8, characterized in that: The included angle between the slip surface and the pitch diameter is 48° to 54°.

10. The thick-thin toothed disc according to claim 1, characterized in that: The driving surface has a limiting protrusion connected to the rear side tooth bottom or the front side tooth bottom and protruding toward the transmission direction.

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