High-safety ratchet wheel structure of bicycle

Abstract

The utility model relates to a high-safety ratchet wheel structure of a bicycle, which comprises a ratchet wheel fixed with a shaft hole end of a hub shell, pawls uniformly distributed on a flywheel shaft end in the hub shell, and independent curved reeds abutted against ventral surfaces of the pawls, the number of the pawls is equal to that of the reeds, and the pawls are in one-to-one correspondence with the reeds. Three acute-angle-shaped ratchets meshed with inner teeth of the ratchet wheel are arranged on the back face of the outer side of the pawl, the reed is provided with a short reed foot making contact with the flywheel shaft, a long reed foot facing the ventral face of the pawl and an arc-shaped bent part connecting the short reed foot and the long reed foot, and a folded edge inclining towards one side of the short reed foot is arranged at the end of the long reed foot. And the bending part of the folding edge is propped against the ventral surface of the pawl. The pawls are in one-to-one correspondence through the independent curved reeds, the pawls do not influence one another, the three ratchets are arranged on the back face of the outer side of each pawl, the contact area between the pawls and the ratchet wheel is increased, the meshing stability of the pawls and the ratchet wheel is improved, the pawls are prevented from slipping off from the ratchet wheel, and the continuity and safety of riding are guaranteed.

Description

Technical Field

[0001] The utility model belongs to the field of bicycle transmission, in particular to a high-safety ratchet structure for a bicycle. Background Art

[0002] The bicycle hub is a key component of a bicycle. The spokes support the rim, maintaining the wheel's shape and allowing it to roll stably on the ground. The internal rotating structure of the hub allows the axle and housing to rotate relatively freely, allowing the wheel to rotate smoothly around the axle. The hub consists of the hub shell, the axle core structure at the center of the hub, the rotating structure between the central axle and the hub shell, and the ratchet structure.

[0003] There are many types of ratchet structures in the hub. The most common one is the spring pawl ratchet structure, which consists of a ratchet, a pawl and a spring. The ratchet is usually installed on the hub shaft or on a component connected to the shaft, and the pawl engages with the ratchet tooth groove through the force of the spring.

[0004] However, in the current transmission structure, the end position of the pawl is often used to abut against the teeth on the inner ring surface of the ratchet to transmit power, and the contact area is relatively small. During the operation of the bicycle, especially when subjected to large forces, such as when the rider pedals hard to accelerate, climbs a slope, or rides on rough roads, the pawl can easily slip off the inner teeth of the ratchet, resulting in interruption of the bicycle's power transmission and affecting the continuity and safety of riding.

[0005] The pawl is controlled by a ring-shaped steel wire spring, which acts as an elastic element. The pawl's position is affected by this spring. If the spring's force decreases, the engagement between the pawl and the ratchet wheel weakens. Under rapid wheel rotation or high impact, the pawl could disengage from the ratchet teeth. Once the pawl disengages, the hub will briefly spin, causing the wheel to lose power. When the pawl reengages the ratchet teeth, it may jump, causing the hub to rotate unsteadily. This can cause noticeable wheel jerking during riding, impacting the ride experience. It can also cause additional wear on other internal hub components, shortening the lifespan of the hub. Summary of the Invention

[0006] The utility model solves the defect that the existing pawl and ratchet adopt a top-to-top transmission mode, which has a small contact area and causes the pawl to easily slip off the ratchet, resulting in interruption of power transmission and affecting the continuity and safety of riding. The utility model provides a high-safety ratchet structure for bicycles, in which three claw teeth are arranged on the back of the pawl, and the three claw teeth are engaged with the gear teeth of the ratchet, thereby increasing the contact area between the pawl and the ratchet, thereby improving the meshing stability of the pawl and the ratchet, preventing the pawl from slipping off the ratchet, and ensuring the continuity and safety of riding.

[0007] The utility model also solves the problem in the prior art that all pawls are controlled by an annular steel wire spring as an elastic member, and the pawl is greatly affected by the annular steel wire spring. The pawl is easily separated from the ratchet and jumps teeth due to the decrease in the elastic force of the annular steel wire spring. A high-safety ratchet structure for bicycles is provided, which adopts an independent curved spring leaf as the pawl supporting elastic member. One spring leaf only acts on one pawl, and there is no influence between the spring leaves, thereby ensuring the engagement of the pawl and the ratchet, and improving the safety of the ratchet structure.

[0008] The specific technical solution of the utility model is: a high-safety ratchet structure for a bicycle, comprising a ratchet fixed to the shaft hole end of a hub shell, pawls evenly distributed on the flywheel shaft end in the hub shell, and an independent curved reed abutting the ventral surface of the pawl, the number of pawls and reeds being equal, the pawls and reeds corresponding one to one, the outer back surface of the pawl being provided with three acute-angled ratchet teeth meshing with the inner teeth of the ratchet, the reed having a short reed foot in contact with the flywheel shaft, a long reed foot facing the ventral surface of the pawl, and an arc-shaped bent portion connecting the short reed foot and the long reed foot, the end of the long reed foot being provided with a folded edge inclined toward one side of the short reed foot, the bent portion of the folded edge abutting the ventral surface of the pawl.

[0009] The pawls are matched one by one and supported independently by independent curved springs. The pawls will not affect each other. Even if one of the springs has a problem, it will not affect the normal transmission of other pawls. Three ratchet teeth are set on the outer back of the pawl, and the ratchet teeth are acute-angled, thereby increasing the contact area between the pawl and the inner teeth of the ratchet wheel, improving the engagement stability of the pawl and the ratchet wheel, and preventing the pawl from slipping off the ratchet wheel, ensuring the continuity and safety of riding. A folded edge is set at the end of the reed, and the bent part generated by the folded edge contacts the ventral surface of the pawl, thereby reducing the friction between the reed and the pawl, improving the flexibility of the pawl rotation, and avoiding the scratches and friction stress caused by the reed on the pawl.

[0010] Preferably, the inner teeth of the ratchet are triangular oblique teeth, and the ratchet teeth of the pawl are triangular oblique teeth. The tooth top angle of the inner teeth of the ratchet is 90°, and the tooth groove angle is 84°. The tooth top angle of the ratchet teeth of the pawl is 84°, and the tooth groove angle is 90°. One side of the ratchet teeth is the transmission contact surface, and the transmission contact surfaces of the three ratchet teeth on the pawl are spaced 6° apart from each other.

[0011] Preferably, the pawl includes a cylindrical rotating portion, wherein the inner ventral surface of the pawl, where it contacts the spring, is a concave arc surface, and the axis of the rotating portion is located outside the circle of the pawl's arc surface. The arc surface at the contact point between the pawl and the spring optimizes the direction of the force exerted by the spring on the pawl, thereby facilitating the pawl's rebound.

[0012] Preferably, the central angle of the arc-shaped curved portion is 304°, and the inward inclination angle of the folded edge relative to the long spring leg is 60°.

[0013] Preferably, six mounting grooves are provided at the shaft end of the flywheel shaft, each mounting groove includes a pawl groove and a reed groove, the pawl groove and the reed groove are both circular with openings, the radius of the circle where the center of the pawl groove is located is larger than the radius of the circle where the center of the reed groove is located, and the opening of the pawl groove and the opening of the reed groove are opposite to each other.

[0014] Preferably, the two sides of the opening of the mounting groove are parallel straight edges, the central angle of the pawl groove is 250°, the central angle of the reed groove is 252°, the bottom of the mounting groove is between the pawl groove and the reed groove, and the bottom of the groove is inclined relative to the line between the center of the pawl groove and the center of the reed groove, with an inclination angle of 7°, and the end facing the pawl groove is higher than the end facing the reed groove.

[0015] Preferably, the six mounting slots are divided into two groups, each group including three mounting slots evenly spaced at 120° intervals, the interval angles between adjacent mounting slots are 57° and 63° respectively, the interval angle between the mounting slots on the reed slot side is 57°, and the interval angle between the mounting slots on the pawl slot side is 63°.

[0016] Preferably, a relief groove is provided on the axial end surface of the flywheel shaft corresponding to the mounting groove. The relief groove has a depth of 0.1 mm and comprises a relief groove bottom that coincides with the bottom of the mounting groove, a first arcuate segment that coincides with the arc of the pawl groove, and a second arcuate segment that coincides with the arc of the reed groove. The first arcuate segment, the relief groove bottom, and the second arcuate segment are connected by an arc-shaped transition. The relief groove is provided at the end of the flywheel shaft to reduce the contact area between the pawl and the reed relative to the flywheel shaft, thereby reducing rotational resistance.

[0017] Preferably, a flange is provided at the end of the flywheel shaft. The flange's outer diameter is larger than the diameter of the pawl's closest point to the flywheel shaft's axis. A clearance notch is provided on the flange corresponding to the pawl and spring. A plastic retaining ring is positioned within a gap formed between the inner surface of the flange and the sides of the pawl and spring. The clearance notch facilitates installation of the pawl and spring, while the plastic retaining ring prevents the pawl and spring from falling out, enhancing safety.

[0018] The beneficial effects of the present utility model are as follows: the pawls are respectively supported and correspond to independent curved springs one by one, the pawls will not affect each other, and even if one of the springs has a problem, it will not affect the normal transmission of other pawls; three ratchet teeth are arranged on the outer back side of the pawl, and the ratchet teeth are acutely angled, thereby increasing the contact area between the pawl and the inner teeth of the ratchet wheel, improving the meshing stability of the pawl and the ratchet wheel, avoiding the pawl from slipping off the ratchet wheel, and ensuring the continuity and safety of riding; a folded edge is arranged on the end of the spring, and the bent portion generated by the folded edge contacts the ventral surface of the pawl, thereby reducing the friction between the spring and the pawl, improving the flexibility of the pawl rotation, and avoiding the scratching and friction stress generated by the spring on the pawl. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of the utility model;

[0020] Figure 2 This is a schematic diagram of the cooperation between a pawl and a spring in the utility model;

[0021] Figure 3 This is a schematic diagram of a reed structure of the utility model;

[0022] Figure 4 This is a schematic diagram of the installation position structure of a pawl and a spring in the utility model;

[0023] Figure 5 This is a schematic diagram of the flywheel shaft structure of the utility model;

[0024] In the figure: 1. ratchet, 2. pawl, 3. reed, 4. flywheel shaft, 5. rotating part, 6. ratchet, 7. belly, 8. folded edge, 9. short reed foot, 10. arc-shaped bending part, 11. long reed foot, 12. pawl groove, 13. avoidance groove, 14. reed groove, 15. mounting groove, 16. retaining edge. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to specific embodiments and in conjunction with the accompanying drawings. Example

[0026] like Figure 1As shown, a high-safety ratchet structure for a bicycle comprises a ratchet 1 fixed to the shaft hole end of a hub shell, a pawl 2 evenly distributed on the end of a flywheel shaft 4 in the hub shell, and an independent curved reed 3 abutting against the ventral surface 7 of the pawl, wherein the number of the pawls is equal to the number of the reeds, and the pawls and reeds correspond one to one, and the outer back surface of the pawl is provided with three acute-angled ratchet teeth 6 meshing with the inner teeth of the ratchet; the reed comprises a short reed foot 9 in contact with the flywheel shaft, a long reed foot 11 facing the ventral surface of the pawl, and an arc-shaped bent portion 10 connecting the short reed foot and the long reed foot, the length of the long reed foot being greater than that of the short reed foot, and the end of the long reed foot is provided with a folded edge 8 tilted toward one side of the short reed foot, and the bent portion of the folded edge abuts against the ventral surface of the pawl.

[0027] like Figure 2 As shown, the pawl includes a cylindrical rotating portion 5. The inner ventral surface of the pawl, where it contacts the leaf spring, is a concave arc surface. The axis of the rotating portion is located outside the circle of the pawl's arc surface. The ratchet wheel's internal teeth are triangular and helical, and the pawl's ratchet teeth are triangular and helical. The ratchet wheel's internal teeth have a 90° top angle and an 84° tooth groove angle, while the pawl's ratchet teeth have a 84° top angle and a 90° tooth groove angle. One side of the ratchet teeth serves as a transmission contact surface. The transmission contact surfaces of the three ratchet teeth on the pawl are inclined 6° apart, with the ends gradually converging inward.

[0028] like Figure 3 As shown, the central angle of the arc-shaped curved portion of the reed is 304°, and the inward inclination angle of the folded edge relative to the long reed leg is 60°.

[0029] like Figure 4 Figure 5 As shown, six mounting slots 15 are provided at the end of the flywheel shaft. Each mounting slot includes a pawl slot 12 and a reed slot 14. The pawl slot and the reed slot are both circular with an opening. The radius of the circle containing the center of the pawl slot is greater than the radius of the circle containing the center of the reed slot. The opening of the pawl slot and the opening of the reed slot are opposite each other. The opening of the mounting slot is flanked by parallel straight edges. The central angle of the pawl slot is 250°, and the central angle of the reed slot is 252°. The bottom of the mounting slot is located between the pawl slot and the reed slot. The bottom is inclined relative to the line connecting the center of the pawl slot and the center of the reed slot at an angle of 7°, with the end facing the pawl slot being higher than the end facing the reed slot. The 6 mounting slots are divided into two groups, each group includes 3 mounting slots evenly spaced at 120° intervals. The interval angles between adjacent mounting slots are 57° and 63° respectively. The interval angle between the mounting slots on the reed slot side is 57°, and the interval angle between the mounting slots on the pawl slot side is 63°.

[0030] A relief groove 13 is provided on the axial end face of the flywheel shaft corresponding to the mounting groove. The relief groove has a depth of 0.1 mm and comprises a relief groove bottom that coincides with the bottom of the mounting groove, a first arcuate segment that matches the arc of the pawl groove, and a second arcuate segment that matches the arc of the spring groove. The first arcuate segment, the relief groove bottom, and the second arcuate segment are connected by an arc-shaped transition. A rib 16 is provided at the end of the flywheel shaft. The rib's outer diameter is larger than the diameter of the pawl closest to the flywheel shaft's axis. Relief notches are provided on the rib corresponding to the pawl and spring. A gap is formed between the inner surface of the rib and the side edges of the pawl and spring, and a plastic retaining ring is provided in this gap. The rotating part of the pawl is arranged in the pawl groove, the arc-shaped curved part of the spring is arranged in the spring groove, the end of the pawl is biased to one side of the spring, the short spring foot of the spring is in contact with the bottom plane of the installation groove, and the bent part of the folded edge at the end of the long spring foot is in contact with the ventral surface of the pawl.

[0031] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation of the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A high-safety ratchet structure for a bicycle, characterized in that: The invention comprises a ratchet (1) fixed to the shaft hole end of the hub shell, a pawl (2) uniformly distributed on the flywheel shaft end in the hub shell, and an independent curved reed (3) abutting the ventral surface of the pawl, wherein the number of the pawl and the reed is equal, and the pawl and the reed correspond to each other one by one, and the outer back of the pawl is provided with three acute-angled ratchet teeth (6) meshing with the inner teeth of the ratchet. The reed has a short reed foot (9) in contact with the flywheel shaft, a long reed foot (11) facing the ventral surface of the pawl, and an arc-shaped curved portion (10) connecting the short reed foot and the long reed foot, and the end of the long reed foot is provided with a folded edge (8) tilted toward one side of the short reed foot, and the bent portion of the folded edge abuts the ventral surface of the pawl.

2. A high-safety ratchet structure for a bicycle according to claim 1, characterized in that: The inner teeth of the ratchet are triangular and oblique, and the ratchet teeth of the pawl are triangular and oblique. The tooth top angle of the inner teeth of the ratchet is 90°, and the tooth groove angle is 84°, while the tooth top angle of the ratchet teeth of the pawl is 84°, and the tooth groove angle is 90°. One side of the ratchet teeth is the transmission contact surface, and the transmission contact surfaces of the three ratchet teeth on the pawl are spaced 6° apart from each other.

3. The high-safety ratchet structure for a bicycle according to claim 1, characterized in that: The pawl comprises a cylindrical rotating portion (5), the portion where the inner ventral surface of the pawl contacts the spring sheet is a concave arc surface, and the axis of the rotating portion is located outside the circle where the pawl arc surface is located.

4. The high-safety ratchet structure for a bicycle according to claim 1, characterized in that: The central angle of the arc-shaped bending portion is 304°, and the inward inclination angle of the folded edge relative to the long spring leg is 60°.

5. A high-safety ratchet structure for a bicycle according to claim 1, 2, 3 or 4, characterized in that: Six mounting grooves (15) are provided at the shaft end of the flywheel shaft, each mounting groove including a pawl groove (12) and a reed groove (14), the pawl groove and the reed groove both being circular with openings, the radius of the circle where the center of the pawl groove is located being larger than the radius of the circle where the center of the reed groove is located, and the opening of the pawl groove and the opening of the reed groove are opposite to each other.

6. A high-safety ratchet structure for a bicycle according to claim 5, characterized in that: The two sides of the opening of the mounting groove are parallel straight edges, the central angle of the pawl groove is 250°, the central angle of the reed groove is 252°, and the bottom of the mounting groove is between the pawl groove and the reed groove. The bottom of the groove is inclined relative to the line between the center of the pawl groove and the center of the reed groove, with an inclination angle of 7°, and the end facing the pawl groove is higher than the end facing the reed groove.

7. A high-safety ratchet structure for a bicycle according to claim 6, characterized in that: The 6 mounting slots are divided into two groups, each group includes 3 mounting slots evenly spaced at 120° intervals. The interval angles between adjacent mounting slots are 57° and 63° respectively. The interval angle between the mounting slots on the reed slot side is 57°, and the interval angle between the mounting slots on the pawl slot side is 63°.

8. The high-safety ratchet structure for a bicycle according to claim 5, characterized in that: An avoidance groove (13) is provided on the axial end surface of the flywheel shaft corresponding to the mounting groove, the avoidance groove has a depth of 0.1 mm, and the avoidance groove has an avoidance groove bottom that coincides with the groove bottom of the mounting groove, a first arc segment that coincides with the circular arc of the pawl groove, and a second arc segment that coincides with the circular arc of the reed groove, and the first arc segment, the avoidance groove bottom, and the second arc segment are connected and transitioned by an arc.

9. A high-safety ratchet structure for a bicycle according to claim 1, 2, 3 or 4, characterized in that: A rib (16) is provided at the end of the flywheel shaft, the outer diameter of the rib being larger than the diameter of the portion of the pawl closest to the axis of the flywheel shaft, and an avoidance recess is provided on the rib corresponding to the position of the pawl and the spring; a gap is formed between the inner surface of the rib and the side edge of the pawl and the side edge of the spring, and a plastic retaining ring is provided in the gap.

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