TWI880659B - Improved shift-up structure of bicycle sprocket - Google Patents

Abstract

An improved shift-up structure of bicycle sprocket comprises: a sprocket body having a plurality of engaging teeth arranged around an outer peripheral surface thereof; a shifting promoting portion provided on the sprocket body and adjacent to an outer peripheral surface of the sprocket for promoting a chain to move from the sprocket body to an adjacent smaller sprocket body; the shifting promoting portion comprising a shifting promoting tooth and a shifting promoting recess; the top end of the shifting promoting tooth having a shifting tooth top surface; the shifting promoting recess communicating with the shifting promoting tooth; and a lift-off tooth provided on the outer peripheral surface of the sprocket body and adjacent to the shifting promoting tooth for preventing the chain from moving from the sprocket body to the adjacent smaller sprocket body; the top end of the lift-off tooth having a lift-off tooth top surface; wherein the height of the lift-off tooth top surface is smaller than the height of the shifting tooth top surface; the thickness of the lift-off tooth top surface is smaller than the thickness of the shifting tooth top surface; and the width of the lift-off tooth top surface is smaller than the width of the shifting tooth top surface.

Description

Improvement of bicycle gear upshift structure

The present invention relates to a bicycle gear, and in particular to an improved bicycle gear upshift structure that can limit the upshift position of the chain.

According to the current bicycle, the speed can be changed through gears of different sizes when riding. Basically, the front and rear gearshifters are combined with gears of different sizes to change the transmission ratio of the chain between the gears. This design allows the rider to adjust the speed of the pedals under different conditions to cope with different speeds and terrains.

Generally speaking, one of the most common ways to change gears is through a rear derailleur and a cassette. The rear wheel of a bicycle is usually equipped with multiple sprockets, each with a different number of teeth, and a rear derailleur located on the rear wheel frame. The function of the rear derailleur is to change the size of the rear sprocket connected by the chain. Without changing the front sprocket, a larger rear sprocket provides a lower gear ratio, making it easier for the rider to go uphill. A smaller rear sprocket provides a higher gear ratio, suitable for fast and flat roads.

However, when the chain moves on the rear gear, problems often occur. For example, when the chain shifts from a larger gear to a smaller gear, it is easy for the chain to take a while to switch from one gear to another during the gear shifting process due to the gear structure. A known gear structure discloses that at least one upshift promotion area and at least one upshift promotion tooth are provided on the gear, so that the chain can move along the upshift promotion area to the adjacent gear through the upshift promotion tooth; however, there is no corresponding restriction structure before and after the upshift promotion tooth, so that the chain may still not be upshifted from the upshift promotion tooth, and the maximum upshift benefit cannot be achieved. Therefore, how to ensure that the chain can upshift when the upshifting gear is used is an urgent issue that needs to be solved by industry players and researchers in related fields.

The main purpose of the invention is to provide an improvement in the gear upshifting structure of a bicycle, which can limit the chain to upshift in the upshifting promotion area, thereby maximizing the upshifting effect.

In order to achieve the above-mentioned invention purpose, the present invention provides an improvement of a bicycle gear upshift structure, comprising: a gear body, having a plurality of meshing teeth surrounding the outer circumference of the gear body; an upshift promotion part, disposed on the gear body and adjacent to the outer circumference of the gear, for promoting a chain to move from the gear body to an adjacent smaller gear body; The gear promotion part includes a gear-up promoting tooth and a gear-up promoting groove; the top end of the gear-up promoting tooth has a gear-up tooth top surface; the gear-up tooth top surface has a first height relative to the bottom of the gear-up promoting tooth, the gear-up tooth top surface has a first thickness along the circumferential direction of the gear plate body, and the gear-up tooth top surface has a first width along the axial direction of the gear plate body; the gear-up promoting groove The groove is connected to the upshift promotion tooth; and an upshift resistance tooth is arranged on the outer peripheral surface of the gear plate body and adjacent to the upshift promotion tooth, so as to prevent the chain from moving from the gear plate body to the adjacent smaller gear plate body; the top end of the upshift resistance tooth has a top surface of the upshift resistance tooth; the top surface of the upshift resistance tooth has a second height relative to the bottom of the upshift resistance tooth, and the top surface of the upshift resistance tooth is along the outer peripheral surface of the gear plate body. The circumferential direction has a second thickness, and the top surface of the lifting resistance tooth has a second width along the axial direction of the gear plate body; wherein the second height of the top surface of the lifting resistance tooth is less than the first height of the top surface of the gear shifting tooth; the second thickness of the top surface of the lifting resistance tooth is less than the first thickness of the top surface of the gear shifting tooth; the second width of the top surface of the lifting resistance tooth is less than the first width of the top surface of the gear shifting tooth.

In one embodiment, the gear disc body has a first side surface and a second side surface respectively on two opposite sides along the axis; the distance between the top surface of the lift-blocking tooth and the first side surface is smaller than the distance between the top surface of the lift-blocking tooth and the second side surface.

In one embodiment, the distance between the top surface of the upshift tooth and the first side surface is greater than the distance between the top surface of the upshift tooth and the second side surface.

In one embodiment, the lift-blocking tooth has a first section and a second section; the first section is connected to the first side of the gear body; the second section is connected to the second side of the gear body; the first section has a first slope relative to the axial direction of the gear body, the second section has a second slope relative to the axial direction of the gear body, and the first slope is greater than the second slope.

In one embodiment, the lift-blocking tooth has a driving surface and a driven surface respectively on two opposite sides along the circumferential direction of the gear plate body; the driving surface and the driven surface are respectively connected to the opposite ends of the top surface of the lift-blocking tooth, and the driven surface is closer to the upshifting promotion tooth than the driving surface; wherein the driving surface has a first curvature, the driven surface has a second curvature, and the first curvature is greater than the second curvature.

In one embodiment, one end of the upshift promotion groove extends below the upshift resistance tooth, and the upshift resistance tooth is not connected to the upshift promotion groove.

In one embodiment, the gear plate body defines a tooth root circle, which is a virtual circle passing through the tooth roots of the meshing teeth; the first height is the distance between the top surface of the upshift tooth and the tooth root circle; the second height is the distance between the top surface of the resistance tooth and the tooth root circle.

In one embodiment, the top surface of the upshift-blocking tooth is offset away from the upshift-facilitating tooth.

The following is a list of preferred embodiments based on the purpose, efficacy and structural configuration disclosed by the present invention, and is described in detail with accompanying drawings.

10: Gear body

11: Base

12: clench teeth

13: First side

14: Second side

20: Shift-up promotion department

21: Upshift promotion gear

210: Top surface of upshift gear

22: Upshift promotion groove

220: Lateral concave surface

221: bottom concave surface

30: Block the ascending teeth

31: Top surface of the tooth that blocks the rise

32: Driving surface

33: Driven side

34: First section

35: Second section

R1: tooth root circle

R2: Tooth top circle

H1: First height

H2: Second height

D1: First thickness

D2: Second thickness

W1: First width

W2: Second width

Figure 1 is a front view of a preferred embodiment of the present invention.

Figure 2 is a partially enlarged front view of a preferred embodiment of the present invention.

Figure 3 is a partially enlarged three-dimensional diagram of a preferred embodiment of the present invention.

Figure 4 is a partially enlarged top view of a preferred embodiment of the present invention.

Figure 5 is a cross-sectional view of the upshift promoting tooth of a preferred embodiment of the present invention.

Figure 6 is a cross-sectional view of the lift-blocking tooth of a preferred embodiment of the present invention.

The following descriptions with reference to the various figures are preferred embodiments of the present invention. It should be understood that the figures and descriptions are for illustrative purposes only and are not intended to limit the present invention. In addition, the terms "upper" and "lower", "left" and "right", "front" and "back", "first" and "second" described in the specification are used to clearly explain the relative positions between components or mechanisms and are not intended to be limiting.

Please refer to FIG. 1 and FIG. 2, the improvement of the gear upshift structure of a bicycle provided by a preferred embodiment of the present invention mainly includes a gear body 10, at least one upshift promotion part 20 and at least one upshift resistance tooth 30. The gear body 10 has an annular base 11 and a plurality of engagement teeth 12, and the engagement teeth 12 extend outwardly along the radial direction of the base 11 and are arranged in an annular shape on the outer peripheral surface of the gear body 10 for engagement with a chain (not shown). The gear body is defined by a tooth root circle R1 and a tooth top circle R2. The tooth root circle R1 is defined as a virtual circle passing through the tooth root of each of the engaging teeth 12. The tooth top circle R2 is defined as a virtual circle passing through the tooth top of each of the engaging teeth 12. The gear plate body 10 has a first side surface 13 and a second side surface 14 on two opposite sides along the axial direction. When the gear plate body 10 is installed in a gear plate assembly, the first side surface 13 faces an adjacent smaller gear plate (not shown), and the second side surface 14 faces away from the adjacent smaller gear plate.

The upshift promotion part 20 is arranged at the edge of the gear body 10 to promote the upshifting action of the chain moving from the gear body 10 to the adjacent smaller gear. In this embodiment, the gear body 10 has three upshift promotion parts 20. The upshift promotion part 20 includes at least one upshift promotion tooth 21 and an upshift promotion groove 22. The upshift promotion tooth 21 is arranged on the outer peripheral surface of the gear body 10, replacing one of the engagement teeth 12. The top end of the upshift promotion tooth 21 has an upshift tooth top surface 210, and the upshift tooth top surface 210 is located on the tooth top circle R2, and has a first height H1 between the upshift tooth top surface 210 and the tooth root of the upshift promotion tooth 21, which represents the vertical distance from the upshift tooth top surface 210 to the tooth root circle R1; the upshift tooth top surface 210 is located on the tooth top circle R2, and has a first height H1 between the upshift tooth top surface 210 and the tooth root circle R1; The main body 10 has a first thickness D1 in the circumferential direction, which represents the length of the upshift tooth top surface 210 extending along the arc of the tooth top circle R2; the upshift tooth top surface 210 has a first width W1 in the axial direction of the gear plate main body 10, which represents the length of the upshift tooth top surface 210 extending along the axial direction of the gear plate main body 10. The distance between the upshift tooth top surface 210 of the upshift promotion tooth 21 and the first side surface 13 is greater than the distance between the upshift tooth top surface 210 and the second side surface 14, so that the upshift tooth top surface 210 of the upshift promotion tooth 21 is offset toward the second side surface 14. Thereby, the chain can more easily complete the upshifting action from the upshifting promotion tooth 21. The upshifting promotion groove 22 is provided on the gear body 10 and adjacent to the outer peripheral surface of the gear body 10, and is connected to the upshifting promotion tooth 21. Specifically, the upshifting promotion groove 22 is formed on the first side surface 13 of the gear body 10 and is recessed in a direction toward the second side surface 14. It is used to reduce the interference between the gear body 10 and the chain during the upshifting of the chain from the gear body 10 to the adjacent smaller gear body. The upshift promotion groove 22 has a side concave surface 220 and a bottom concave surface 221, the side concave surface 220 is connected to the bottom concave surface 221, and the bottom concave surface 221 is farther from the upshift tooth top surface 210 than the side concave surface 220. The side concave surface 220 is generally parallel to the first side surface 13, and the bottom concave surface 221 is inclined relative to the first side surface 13. Thereby, the chain can be guided from the upshift promotion tooth 21 to the adjacent smaller gear plate body by the side concave surface 220 and the bottom concave surface 221 of the upshift promotion groove 22. Among them, one end of the upshift promotion groove 22 extends to the bottom of the lifting resistance tooth 30, and is not connected to the lifting resistance tooth 30.

The anti-lift tooth 30 is disposed on the outer circumference of the gear plate body 10, adjacent to the upshift promotion tooth 21 of the upshift promotion part 20, and there is no other tooth between the anti-lift tooth 30 and the upshift promotion tooth 21. In this embodiment, the number of the anti-lift tooth 30 is three, corresponding to the three upshift promotion parts 20. The anti-lift tooth 30 is used to limit the chain to perform upshifting only in the upshift promotion part 20. Specifically, the anti-lift tooth 30 has a top surface 31 of the anti-lift tooth, a driving surface 32, a driven surface 33, a first cut surface 34 and a second cut surface 35. The top surface 31 of the lifting resistance tooth is located at the top end of the lifting resistance tooth 30, adjacent to the tooth top circle R2, and the top surface 31 of the lifting resistance tooth has a second height H2 relative to the tooth root of the lifting resistance tooth 30, which represents the vertical distance from the top surface 31 of the lifting resistance tooth to the tooth root circle R1. The second height H2 of the top surface 31 of the lifting resistance tooth is less than the first height H1 of the top surface 210 of the gear shifting tooth. The top surface 31 of the lifting resistance tooth has a second thickness D2 along the circumferential direction of the gear plate body 10, which represents the length of the top surface 31 of the lifting resistance tooth extending in the arc direction along the tooth top circle R2. The second thickness D2 of the anti-lift tooth top surface 31 is less than the first thickness D1 of the upshift tooth top surface 210. The anti-lift tooth top surface 31 has a second width W2 along the axial direction of the gear plate body 10, which represents the length of the anti-lift tooth top surface 31 extending along the axial direction of the gear plate body 10. The second width W2 of the anti-lift tooth top surface 31 is less than the first width W1 of the upshift tooth top surface 210. The distance between the top surface 31 of the lift-blocking tooth 30 and the first side surface 13 is smaller than the distance between the top surface 31 of the lift-blocking tooth 30 and the second side surface 14, so that the lift-blocking tooth 30 is offset toward the first side surface 13. Moreover, in this embodiment, the top surface 31 of the lift-blocking tooth is offset in a direction away from the upshift promoting tooth 21.

The driving surface 32 and the driven surface 33 are located on opposite sides of the lift-resistance tooth 30 along the circumferential direction of the gear plate body 10, and are respectively connected to opposite ends of the lift-resistance tooth top surface 31. The driven surface 33 is closer to the upshift promotion tooth 21 relative to the driving surface 32. The driving surface 32 has a first curvature, which represents the degree of curvature of the driving surface 32; the driven surface 33 has a second curvature, which represents the degree of curvature of the driven surface 33. In this embodiment, the first curvature is greater than the second curvature, which means that the driving surface 32 is more curved than the driven surface 33.

The first section 34 and the second section 35 are located at opposite sides of the lift-blocking tooth 30 along the axial direction of the gear plate body 10, and are respectively connected to opposite ends of the lift-blocking tooth top surface 31. The first section 34 is connected to the first side surface 13, and the second section 35 is connected to the second side surface 14. The first section 34 has a first slope, which represents the degree of inclination of the first section 34 relative to the axial direction of the gear plate body 10. The second section 35 has a second slope, which represents the degree of inclination of the second section 35 relative to the axial direction of the gear plate body. In this embodiment, the first slope of the first section 34 is greater than the second slope of the second section 35, or it can be said that the first section 34 is more perpendicular to the axial direction of the gear plate body 10 than the second section 35.

According to the above structure, when the chain moves to the position of the lift-blocking tooth 30, since the lift-blocking tooth 30 is offset toward the first side surface, the top surface 31 of the lift-blocking tooth is smaller, the driven surface 33 is raised relative to the driving surface 32, and the second section 35 is flatter than the first section 34, so the main part of the chain will fall on the back side of the lift-blocking tooth 30 and cannot be shifted by the rear gearshift, so that the chain can only perform the upshift action when it moves to the next group of the upshift promotion part 20. Therefore, the lift-blocking tooth 30 can limit the chain to perform the upshift action only at the upshift promotion part 20.

In summary, the improvement of the bicycle gear upshift structure provided by the present invention can effectively restrict the chain from upshifting at the upshift-resistance tooth through the structure of the upshift-resistance tooth adjacent to the upshift-promoting tooth, thereby restricting the chain from upshifting at the upshift-promoting portion, thereby maximizing the upshifting efficiency.

The above embodiments are only for illustrative purposes to illustrate the technology and its effects of the present invention, and are not intended to limit the present invention. Any person skilled in the art may modify and change the above embodiments without violating the technical principles and spirit of the present invention. Therefore, the scope of protection of the present invention shall be as described below in the scope of the patent application.

10: Gear plate body

11: Base

12: Teeth clenching

20: Shift-up promotion department

21: Upshift promotion gear

22: Upshift promotion groove

30: Block the ascending teeth

R1: tooth root circle

R2: Tooth top circle

Claims (6)

An improvement of a gear upshifting structure of a bicycle comprises: a gear body having a plurality of meshing teeth surrounding the outer circumference of the gear body; an upshifting promotion part arranged on the gear body and adjacent to the outer circumference of the gear body, for promoting a chain to move from the gear body to an adjacent smaller gear body; the upshifting promotion part comprises an upshifting promotion tooth and an upshifting promotion groove; the top end of the upshifting promotion tooth has an upshifting tooth top surface; the The top surface of the upshift tooth has a first height relative to the bottom of the upshift promotion tooth, the top surface of the upshift tooth has a first thickness along the circumferential direction of the gear plate body, and the top surface of the upshift tooth has a first width along the axial direction of the gear plate body; the upshift promotion groove is connected to the upshift promotion tooth; and a gear stopper is arranged on the outer circumferential surface of the gear plate body and adjacent to the upshift promotion tooth to prevent the chain from moving from the gear plate body to the adjacent smaller tooth The tooth plate body; the top end of the anti-lift tooth has a top surface of the anti-lift tooth; the top surface of the anti-lift tooth has a second height relative to the bottom of the anti-lift tooth, the top surface of the anti-lift tooth has a second thickness along the circumferential direction of the tooth plate body, and the top surface of the anti-lift tooth has a second width along the axial direction of the tooth plate body; wherein the second height of the top surface of the anti-lift tooth is less than the first height of the top surface of the gear-up gear; the second thickness of the top surface of the anti-lift tooth is less than the top surface of the gear-up gear. The first thickness of the gear plate; the second width of the top surface of the lifting resistance tooth is smaller than the first width of the top surface of the gear shifting tooth; wherein the gear plate body has a first side surface and a second side surface respectively on two opposite sides along the axis; the distance between the top surface of the lifting resistance tooth and the first side surface is smaller than the distance between the top surface of the lifting resistance tooth and the second side surface; wherein the distance between the top surface of the gear shifting tooth and the first side surface is greater than the distance between the top surface of the gear shifting tooth and the second side surface. The improvement of the gear upshift structure of a bicycle as described in claim 1, wherein the gear upshift resistance has a first section and a second section; the first section is connected to the first side of the gear body; the second section is connected to the second side of the gear body; the first section has a first slope relative to the axial direction of the gear body, the second section has a second slope relative to the axial direction of the gear body, and the first slope is greater than the second slope. The improvement of the gear upshift structure of a bicycle as described in claim 1, wherein the lift-resistance tooth has a driving surface and a driven surface respectively on two opposite sides along the circumferential direction of the gear body; the driving surface and the driven surface are respectively connected to the opposite ends of the top surface of the lift-resistance tooth, and the driven surface is closer to the upshift promotion tooth than the driving surface; wherein the driving surface has a first curvature, the driven surface has a second curvature, and the first curvature is greater than the second curvature. An improvement of the upshifting structure of a bicycle gear as described in claim 1, wherein one end of the upshifting promotion groove extends below the upshifting resistance tooth, and the upshifting resistance tooth is not connected to the upshifting promotion groove. The improvement of the bicycle gear shifting structure as described in claim 1, wherein the gear body defines a tooth root circle, which is a virtual circle passing through the tooth roots of the engaging teeth; the first height is the distance between the top surface of the shifting tooth and the tooth root circle; the second height is the distance between the top surface of the lifting resistance tooth and the tooth root circle. An improvement in the bicycle gear upshift structure as described in claim 1, wherein the top surface of the upshift-resisting tooth is offset in a direction away from the upshift-promoting tooth.

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