Bicycle clutch sprocket
By designing a bicycle clutch sprocket, the clutch state is automatically adjusted, solving the problem of the bicycle being difficult to drive near the lowest point, improving the efficiency of climbing and rapid acceleration, and achieving higher power and speed.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANCHANG HANGKONG UNIVERSITY
- Filing Date
- 2024-07-11
- Publication Date
- 2026-07-24
AI Technical Summary
Bicycles are difficult to accelerate when the pedals are near their lowest point, especially when going uphill or accelerating rapidly.
A bicycle clutch sprocket was designed. Through the cooperation of a cylindrical cam and a spring plate, the clutch disc and the sprocket are automatically engaged or disengaged. The clutch state is automatically adjusted by the position change of the protrusion in different pedal travel areas, reducing the travel that is inconvenient to do work.
It improves the power of bicycles when climbing hills and accelerating rapidly, making pedaling easier and facilitating quick passages where it is difficult to work, thus increasing power and speed.
Smart Images
Figure CN118457796B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a bicycle clutch transmission mechanism, and more particularly to a bicycle clutch sprocket. Background Technology
[0002] Over the centuries, through continuous development and improvement, bicycles have become lightweight, agile, easy to operate, and easy to repair, making them ideal for short distances. Bicycles are inexpensive to purchase and use, and have virtually no restrictions, leading to their widespread adoption. However, when the pedals are near their lowest point, it is difficult to accelerate the bicycle.
[0003] The work done by pedaling a bicycle can be divided into four travel zones (e.g., Figure 1 As shown): 1. When the left pedal 1 is in the first travel zone 101 (i.e., 0° to 90°), the right pedal is in the third travel zone 103 (i.e., 180° to 270°), and the left pedal 1 is pressed to perform work; 2. When the left pedal 1 is in the second travel zone 102 (i.e., 90° to 180°), the right pedal is in the fourth travel zone 104 (i.e., 270° to 360°, 360° is also 0°), which is not convenient for performing work, and the foot moves along with the pedal. 3. When the left pedal 1 is in the third travel zone 103 (i.e., 180°~270°), the right pedal is in the first travel zone 101 (i.e., 0°~90°), and the right pedal is used for work. 4. When the left pedal 1 is in the fourth travel zone 104 (i.e., 270°~360°, 360° is also 0°), the right pedal is in the second travel zone 102 (i.e., 90°~180°), making it difficult to use the pedal for work, and the foot moves with the pedal. When riding uphill, it is often difficult to exert force because the pedal is near the lowest point (i.e., the pedal is in the second travel zone 102), forcing a stop. When accelerating rapidly, if the pedal is near the lowest point (i.e., the pedal is in the second travel zone 102), it is difficult to exert force for acceleration, and one can only wait for the pedal to move to the first travel zone 101 before exerting force for acceleration. If the pedal can quickly pass through this difficult travel zone near the lowest point, it will be beneficial for uphill riding and rapid acceleration. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a bicycle clutch sprocket that automatically engages or disengages the bicycle clutch disc from the sprocket, thereby improving bicycle riding efficiency, reducing the rider's operational intensity, and achieving better bicycle riding performance.
[0005] The objective of this invention is achieved as follows: A bicycle clutch sprocket includes a bicycle frame bottom bracket sleeve and a cylindrical cam on its outer side. A bottom bracket is installed inside the bottom bracket sleeve. One end of the bottom bracket has a second square shaft section and a second screw from the inside to the outside. A right crank is fitted onto the second square shaft section, and the right crank, which has a right pedal, is connected to the second square shaft section via a nut on the second screw. The other end of the bottom bracket has a splined shaft, a cylindrical shaft, a first square shaft section, and a first screw sequentially from the inside to the outside. A narrow slit with a flat rectangular cross-section is provided on the inner side of the splined shaft, and this slit radially penetrates the splined shaft. The cylindrical cam is fixedly connected to one end of the bottom bracket sleeve through a central through-hole. Symmetrical protrusions are provided on the outer periphery of the cylindrical cam, with two symmetrical protrusions respectively located in the first and third stroke areas. A clutch disc is fitted onto the splined shaft on the outer side of the bottom bracket via a spline groove, and a spline is provided in the center of the clutch disc. The clutch disc has a first tooth on its outer periphery, and symmetrical rubber pin holes on its outer ring. Threaded holes are located on the outer side of the rubber pin holes. A rubber pin is fixedly installed in the rubber pin hole on the clutch disc by a first set screw. The lower end of the rubber pin contacts the upper surface of the protrusion of the cylindrical cam. A spring plate is inserted into a narrow slot, and the round holes at both ends of the spring plate are connected to the inner side of the clutch disc by screws. A sprocket is mounted on the cylindrical shaft. The sprocket has chain teeth on its outer periphery, and a second tooth on the sprocket body that corresponds to the first tooth of the clutch disc and meshes with the first tooth. A retaining ring is mounted on the cylindrical shaft outside the sprocket and is fixedly connected to the cylindrical shaft by a second set screw. A left crank is mounted on the first square shaft section and is locked by a locking nut on the first screw. A left foot pedal is installed at the other end of the left crank.
[0006] Furthermore, the radius of the outer contour of the protrusion is 55 mm, the width L is 10 mm, and the included angle β between its two end faces is 90°.
[0007] Furthermore, the two ends of the protrusion are provided with inclined surfaces, and the angle between the inclined surfaces and the plane of the cylindrical cam is 145°.
[0008] Furthermore, the upper plane of the protrusion corresponds to the lower end of the rubber post on the clutch disc.
[0009] The working process of a bicycle clutch sprocket is as follows: 1) When the left foot pedal is at 0°, the clutch disc separates from the sprocket under the action of the spring plate. When the left foot pedal is pressed, the left crank drives the bottom shaft, clutch disc and spring plate to rotate. The rubber post is pushed up by the protrusion, which drives the clutch disc to move towards the sprocket. The clutch disc engages with the sprocket. At this time, the spring plate deforms to the maximum. Since the two symmetrical protrusions are located in the first stroke area and the third stroke area respectively, the clutch disc and sprocket remain engaged when the left foot pedal passes through the first stroke area. The left foot pedal drives the left crank, bottom shaft, clutch disc and sprocket to transmit power. 2) When the left foot pedal moves to 90°, the rubber column passes through the end of the protrusion, and under the action of the spring plate, the clutch disc moves towards the cylindrical cam. The clutch disc separates from the sprocket. Since there are no protrusions in the second and fourth stroke zones, the clutch disc remains separated from the sprocket when the left foot pedal passes through the second stroke zone. At this time, the deformation of the spring plate is minimal. The left foot pedal drives the left crank, bottom bracket, and clutch disc to rotate. Since the clutch disc is separated from the sprocket, it cannot drive the sprocket to rotate. The resistance of the left foot pedal passing through the second stroke zone is very small, and the left foot pedal quickly passes through the second stroke zone. 3) When the left pedal moves to 180°, the right pedal reaches 0°. The clutch disc separates from the sprocket under the action of the spring plate. When the right pedal is pressed, the right crank drives the bottom bracket, clutch disc, and spring plate to rotate. The rubber post is pushed up by the protrusion, which drives the clutch disc to move towards the sprocket. The clutch disc engages with the sprocket. At this time, the spring plate deforms to its maximum. Since the two symmetrical protrusions are located in the first stroke area and the third stroke area respectively, the clutch disc and sprocket remain engaged when the left pedal passes through the third stroke area. The right pedal drives the right crank, bottom bracket, clutch disc, and sprocket to transmit power. 4) When the left pedal reaches 270°, the right pedal reaches 90°. The rubber column passes through the end of the protrusion, and under the action of the spring plate, the clutch disc moves towards the cylindrical cam. The clutch disc separates from the sprocket. Since there are no protrusions in the second and fourth stroke zones, the clutch disc remains separated from the sprocket when the left pedal passes through the fourth stroke zone. At this time, the spring plate deformation is minimal. The right pedal drives the right crank, bottom bracket, and clutch disc to rotate. Since the clutch disc is separated from the sprocket, it cannot drive the sprocket to rotate. The resistance of the right pedal passing through the second stroke zone is very small. The right pedal quickly passes through the second stroke zone. When the right pedal reaches 180°, the left pedal reaches 360°. The left pedal returns to the initial position, and the process from step 1) to step 4) is repeated.
[0010] This invention features a simple structure, low cost, stable operation, and easy maintenance. Compared to traditional bicycle sprockets, it can automatically engage or disengage the clutch disc from the sprocket, allowing the pedals to quickly pass through the difficult section near the lowest point. This provides a significant advantage in climbing hills and rapid acceleration, greatly improving power and making pedaling easier and more convenient. Attached Figure Description
[0011] Figure 1 This is a diagram showing the pedal travel zone of a bicycle. Figure 2 This is a partial cross-sectional schematic diagram of the three-dimensional structure of the present invention; Figure 3 This is a three-dimensional cross-sectional schematic diagram of the connection structure between the central shaft 9 and the clutch disc 4 in this invention; Figure 4 This is a schematic diagram of the three-dimensional structure of the sprocket 3 in this invention; Figure 5This is a schematic diagram of the three-dimensional structure of the clutch disc 4 in this invention; Figure 6 This is a three-dimensional structural diagram of the cylindrical cam 6 in this invention; Figure 7 This is a schematic diagram of the three-dimensional structure of the spring sheet 7 in this invention; Figure 8 This is a schematic diagram of the three-dimensional structure of the central axis 9 in this invention.
[0012] In the diagram: 101 - First travel zone, 102 - Second travel zone, 103 - Third travel zone, 104 - Fourth travel zone; 1-Left foot pedal, 2-Left crank, 21-Right crank; 3-Sprocket, 31-Second tooth; 4-Clutch disc, 41-First tooth, 42-Spline groove, 43-Rubber post hole, 44-Threaded hole; 5-Screw, 6-Cylindrical cam, 61-Protrusion, 7-Spring plate, 71-Round hole; 8-Bottom bushing, 9-Central shaft, 91-Spline shaft, 92-Cylindrical shaft, 93-First square shaft section, 94-First screw, 95-Narrow slot, 96-Second square shaft section, 97-Second screw; 10-Rubber post, 11-First set screw, 12-Second set screw, 13-Retaining ring, 14-Locking nut. Detailed Implementation
[0013] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. See also Figures 1 to 8A bicycle clutch sprocket includes a bicycle frame bottom bracket sleeve 8 and a cylindrical cam 6 on its outer side. A bottom bracket sleeve 8 houses a bottom bracket 9. One end of the bottom bracket 9 has a second square shaft section 96 and a second screw 97 arranged from the inside to the outside. A right crank 21 is fitted onto the second square shaft section 96, and the right crank 21, which has a right pedal, is connected to the second square shaft section 96 via a nut on the second screw 97. The other end of the bottom bracket 9 has a splined shaft 91, a cylindrical shaft 92, and a first square shaft arranged sequentially from the inside to the outside. Section 93 and the first screw 94, a narrow slit 95 with a flat rectangular cross-section is provided on the inner side of the spline shaft 91, the narrow slit 95 radially penetrating the spline shaft 91; the cylindrical cam 6 is fixedly connected to one end of the five-way bushing 8 through the middle through hole, the cylindrical cam 6 has symmetrically provided protrusions 61 on its outer periphery, the two symmetrical protrusions 61 are respectively located in the first stroke area 101 and the third stroke area 103. The radius of the outer contour of the protrusion 61 is 55 mm, the width L is 10 mm, and the included angle β of its two end faces is 90°. The two ends of the protrusion 61 are provided with inclined surfaces, the angle between the inclined surfaces and the plane of the cylindrical cam is 145°. The upper plane of the protrusion 61 corresponds to the lower end of the rubber post 10 on the clutch disc 4. A clutch disc 4 is fitted onto a splined shaft 91 on the outer side of the central shaft 9 via a splined groove 42. The clutch disc 4 has a splined groove 42 in the middle, and a first tooth 41 is provided on the outer periphery of the splined groove 42. Rubber post holes 43 are symmetrically arranged on the outer ring of the first tooth 41, and threaded holes 44 are provided on the outer side of the rubber post holes 43. A rubber post 10 is fixedly installed in the rubber post holes 43 on the clutch disc 4 via a first set screw 11. The lower end of the rubber post 10 contacts the upper surface of the protrusion 61 of the cylindrical cam 6. A spring plate 7 is inserted into a narrow slot 95, and screws are used to connect the round holes 71 at both ends of the spring plate 7. 5 is connected to the inner side of the clutch disc 4; a sprocket 3 is mounted on the cylindrical shaft 92, the outer circumference of the sprocket 3 is provided with chain teeth, and the body of the sprocket 3 is provided with a second tooth 31 corresponding to the first tooth 41 of the clutch disc 4, and the second tooth 31 meshes with the first tooth 41; a retaining ring 13 is mounted on the cylindrical shaft 92 outside the sprocket 3, and the retaining ring 13 is fixedly connected to the cylindrical shaft 92 through the second set screw 12; a left crank 2 is mounted on the first square shaft section 93, and the left crank 2 is locked by the locking nut 14 on the first screw 94, and the other end of the left crank 2 is equipped with a left foot pedal 1.
[0014] The working process of a bicycle clutch sprocket is as follows: 1) When the left foot pedal 1 is at 0°, the clutch disc 4 is separated from the sprocket 3 under the action of the spring plate 7. When the left foot pedal 1 is pressed, the left crank 2 drives the central shaft 9, clutch disc 4 and spring plate 7 to rotate. The rubber column 10 is pushed up by the protrusion 61, which drives the clutch disc 4 to move towards the sprocket 3. The clutch disc 4 engages with the sprocket 3. At this time, the spring plate 7 is deformed to the maximum. Since the two symmetrical protrusions 61 are located in the first stroke area 101 and the third stroke area 103 respectively, the clutch disc 4 and the sprocket 3 remain engaged when the left foot pedal 1 passes through the first stroke area 101. The left foot pedal 1 drives the left crank 2, central shaft 9, clutch disc 4 and sprocket 3 to transmit power. 2) When the left foot pedal 1 moves to 90°, the rubber column 10 passes through the end of the protrusion 61, and under the action of the spring plate 7, the clutch disc 4 moves towards the cylindrical cam 6. The clutch disc 4 separates from the sprocket 3. Since the second stroke zone 102 and the fourth stroke zone 104 are not equipped with the protrusion 61, the clutch disc 4 remains separated from the sprocket 3 when the left foot pedal 1 passes through the second stroke zone 102. At this time, the deformation of the spring plate 7 is minimal. The left foot pedal 1 drives the left crank 2, the bottom shaft 9 and the clutch disc 4 to rotate. Since the clutch disc 4 is separated from the sprocket 3, it cannot drive the sprocket 3 to rotate. The resistance of the left foot pedal 1 is very small when passing through the second stroke zone 101. The left foot pedal 1 quickly passes through the second stroke zone 102. 3) When the left foot pedal 1 moves to 180°, the right foot pedal reaches 0°. The clutch disc 4 is separated from the sprocket 3 under the action of the spring plate 7. When the right foot pedal is pressed, the right crank 21 drives the central shaft 9, the clutch disc 4 and the spring plate 7 to rotate. The rubber column 10 is pushed up by the protrusion 61, which drives the clutch disc 4 to move towards the sprocket 3. The clutch disc 4 engages with the sprocket 3. At this time, the spring plate 7 is deformed to the maximum. Since the two symmetrical protrusions 61 are located in the first stroke area 101 and the third stroke area 103 respectively, the clutch disc 4 and the sprocket 3 remain engaged when the left foot pedal 1 passes through the third stroke area 103. The right foot pedal drives the right crank 21, the central shaft 9, the clutch disc 4 and the sprocket 3 to transmit power. 4) When the left foot pedal 1 moves to 270°, the right foot pedal reaches 90°. The rubber column 10 passes through the end of the protrusion 61, and under the action of the spring plate 7, the clutch disc 4 moves towards the cylindrical cam 6. The clutch disc 4 separates from the sprocket 3. Since the second stroke zone 102 and the fourth stroke zone 104 are not equipped with protrusion 61, the clutch disc 4 remains separated from the sprocket 3 when the left foot pedal 1 passes through the fourth stroke zone 104. At this time, the deformation of the spring plate 7 is minimal. The right foot pedal drives the right crank 21, the central shaft 9 and the clutch disc 4 to rotate. Since the clutch disc 4 is separated from the sprocket 3, it cannot drive the sprocket 3 to rotate. The resistance of the right foot pedal passing through the second stroke zone 102 is very small. The right foot pedal quickly passes through the second stroke zone 102. When the right foot pedal reaches 180°, the left foot pedal 1 reaches 360°. The left foot pedal 1 returns to the initial position, and the process from step 1) to step 4) is repeated.
[0015] This invention can automatically engage or disengage the clutch disc and sprocket, ensuring stable, safe, and reliable operation. It allows the pedals to quickly pass through the lowest point of the stroke where it is inconvenient to perform work, especially when climbing hills and accelerating rapidly, resulting in smoother riding action. It increases power by more than 50% and improves speed by 30% compared to traditional bicycles, making pedaling easy and convenient.
Claims
1. A bicycle clutch sprocket, comprising a bicycle frame bottom bracket sleeve (8) and a cylindrical cam (6) on its outer side, characterized in that, The five-way bushing (8) is fitted with a central shaft (9). One end of the central shaft (9) is provided with a second square shaft section (96) and a second screw (97) from the inside to the outside. The second square shaft section (96) is fitted with a right crank (21). The right crank (21) with the right foot pedal is connected to the second square shaft section (96) through a nut on the second screw (97). The other end of the central shaft (9) is provided with a spline shaft (91), a cylindrical shaft (92), a first square shaft section (93) and a first screw (94) from the inside to the outside. The spline shaft (91) has a narrow slit with a flat rectangular cross-section on its inner side. 95), the narrow slit (95) radially penetrates the spline shaft (91); the cylindrical cam (6) is fixedly connected to one end of the five-way bushing (8) through the middle through hole, and the cylindrical cam (6) is symmetrically provided with protrusions (61) on the outer periphery, the two symmetrical protrusions (61) are respectively located in the first stroke area (101) and the third stroke area (103); the spline shaft (91) on the outer side of the central shaft (9) is fitted with a clutch disc (4) through the spline groove (42), the clutch disc (4) is provided with a spline groove (42) in the middle, and the outer periphery of the spline groove (42) is provided with a first tooth (41), the first tooth (41) 1) Rubber post holes (43) are symmetrically arranged on the outer ring body. Threaded holes (44) are arranged on the outer side of the rubber post holes (43). A rubber post (10) is fixedly installed in the rubber post holes (43) on the clutch disc (4) by the first set screw (11). The lower end of the rubber post (10) contacts the upper surface of the protrusion (61) of the cylindrical cam (6). A spring plate (7) is inserted into the narrow slot (95). The round holes (71) at both ends of the spring plate (7) are connected to the inner side of the clutch disc (4) by screws (5). A sprocket (3) is mounted on the cylindrical shaft (92). The outer circumference of the sprocket (3) is provided with... The sprocket (3) is provided with a chain tooth, and the sprocket (3) is provided with a second tooth (31) corresponding to the first tooth (41) of the clutch disc (4), and the second tooth (31) meshes with the first tooth (41); a retaining ring (13) is fitted on the cylindrical shaft (92) on the outer side of the sprocket (3), and the retaining ring (13) is fixedly connected to the cylindrical shaft (92) through the second set screw (12); a left crank (2) is fitted on the first square shaft section (93), and the left crank (2) is locked by the locking nut (14) on the first screw (94), and a left foot pedal (1) is installed at the other end of the left crank (2).
2. The bicycle clutch sprocket according to claim 1, characterized in that, The outer contour of the protrusion (61) has a radius of 55 mm, a width L of 10 mm, and an included angle β of 90° between its two end faces.
3. The bicycle clutch sprocket according to claim 1, characterized in that, The two ends of the protrusion (61) are provided with inclined surfaces, and the angle between the inclined surfaces and the plane of the cylindrical cam (6) is 145°.
4. The bicycle clutch sprocket according to claim 1, characterized in that, The upper surface of the protrusion (61) corresponds to the lower end of the rubber post (10) on the clutch disc (4).
5. The working process of a bicycle clutch sprocket as described in claim 1, characterized in that, The steps are as follows: 1) When the left foot pedal (1) is at 0°, the clutch disc (4) is separated from the sprocket (3) under the action of the spring plate (7). When the left foot pedal (1) is stepped on, the left crank (2) drives the central shaft (9), clutch disc (4) and spring plate (7) to rotate. The rubber column (10) is lifted by the protrusion (61), which drives the clutch disc (4) to move towards the sprocket (3). The clutch disc (4) meshes with the sprocket (3). At this time, the spring plate (7) deforms to the maximum. Since the two symmetrical protrusions (61) are located in the first stroke area (101) and the third stroke area (103) respectively, the clutch disc (4) and sprocket (3) remain engaged when the left foot pedal (1) passes through the first stroke area (101). The left foot pedal (1) drives the left crank (2), central shaft (9), clutch disc (4) and sprocket (3) to transmit power. 2) When the left foot pedal (1) moves to 90°, the rubber column (10) passes through the end of the protrusion (61), and under the action of the spring plate (7), the clutch disc (4) moves towards the cylindrical cam (6), and the clutch disc (4) separates from the sprocket (3). Since the second stroke zone (102) and the fourth stroke zone (104) are not equipped with protrusions (61), the clutch disc (4) and the sprocket (3) remain separated when the left foot pedal (1) passes through the second stroke zone (102). At this time, the deformation of the spring plate (7) is minimal. The left foot pedal (1) drives the left crank (2), the central shaft (9) and the clutch disc (4) to rotate. Since the clutch disc (4) is separated from the sprocket (3), it cannot drive the sprocket (3) to rotate. The resistance of the left foot pedal (1) passing through the second stroke zone (102) is very small, and the left foot pedal (1) quickly passes through the second stroke zone (102). 3) When the left foot pedal (1) moves to 180°, the right foot pedal reaches 0°. The clutch disc (4) is separated from the sprocket (3) under the action of the spring plate (7). When the right foot pedal is pressed, the right crank (21) drives the central shaft (9), clutch disc (4) and spring plate (7) to rotate. The rubber column (10) is pushed up by the protrusion (61), which drives the clutch disc (4) to move towards the sprocket (3). The clutch disc (4) meshes with the sprocket (3). At this time, the spring plate (7) deforms to the maximum. Since the two symmetrical protrusions (61) are located in the first stroke area (101) and the third stroke area (103) respectively, the clutch disc (4) and sprocket (3) remain engaged when the left foot pedal (1) passes through the third stroke area (103). The right foot pedal drives the right crank (21), central shaft (9), clutch disc (4) and sprocket (3) to transmit power. 4) When the left foot pedal (1) moves to 270°, the right foot pedal reaches 90°. The rubber column (10) passes through the end of the protrusion (61), and under the action of the spring plate (7), the clutch disc (4) moves towards the cylindrical cam (6). The clutch disc (4) separates from the sprocket (3). Since the second stroke zone (102) and the fourth stroke zone (104) are not equipped with protrusions (61), the clutch disc (4) remains separated from the sprocket (3) when the left foot pedal (1) passes through the fourth stroke zone (104). At this time, the spring plate (7) deforms the least; the right foot pedal drives the right crank (21), the central shaft (9) and the clutch disc (4) to rotate. Since the clutch disc (4) is separated from the sprocket (3), it cannot drive the sprocket (3) to rotate. The right foot pedal has very little resistance when passing through the second stroke zone (102). The right foot pedal quickly passes through the second stroke zone (102). When the right foot pedal reaches 180°, the left foot pedal (1) reaches 360°. The left foot pedal (1) returns to the initial position and repeats the process from step 1) to step 4).