Speed ​​sprocket

Abstract

The present invention relates to a speed-changing sprocket, wherein: the sprocket fixing plate is circular and provided with a plurality of elliptical holes, a circular rack with a variable opening diameter is movably mounted on the periphery, and the protruding portion of the rack is movably mounted at the elliptical hole position of the sprocket fixing plate by means of screws; a guide rail, an adjusting rod and an adjusting screw are arranged on the sprocket fixing plate, and two adjusting rods are forked, one end of the forked rods is respectively connected to the screws in the elliptical holes, and the crossed end is connected to the adjusting screw; the adjusting screw is inserted into the elliptical hole at the intersection of the two adjusting rods, and the other end is inserted into the guide rail and moves along the guide rail; when the adjusting screw moves to the left, the adjusting rod is pulled and the screw is driven to move inward along the elliptical hole, and the two end faces of the rack are close to reduce the diameter of the rack, and when the adjusting screw moves to the right, the two end faces of the rack are separated and the screw is driven to move outward in the elliptical hole to increase the diameter of the rack. The present invention utilizes the deformation of the material to change the diameter of the sprocket.

Description

Technical Field

[0001] The invention belongs to the category of electromechanical devices, and in particular relates to a speed-changing sprocket for changing the diameter of a bicycle sprocket. Background Art

[0002] In the field of bicycles, the requirements for speed change are very high. A good speed change system often requires more than a dozen gears, and the speed ratio of each gear is very small.

[0003] In order to achieve speed change, the structure requires not only adding sprockets or flywheels, but also a derailleur mechanism to shift the chain from one wheel to another. If a sprocket is added, a chain derailleur mechanism to shift the sprocket is required; if a flywheel is added, a chain derailleur mechanism to shift the flywheel is required. If both sprockets and flywheels are added, two sets of derailleur mechanisms are required. In this way, the speed change system becomes very complicated.

[0004] To make the speed change structure simpler, current bicycle speed change systems generally use a sprocket, a plurality of flywheels and a flywheel chain shifting mechanism. However, in order to realize more than ten gears of speed change, more than ten flywheels are needed, and the structure of such a speed change system is also very complicated.

[0005] If a sprocket has two different diameters, it means that the sprocket can have two speeds. If such a sprocket is applied to the speed change system of a bicycle, the number of flywheels used to achieve the same number of speed changes can be reduced by half, so the speed change system will be much simpler.

[0006] In view of this, technicians in this field are committed to developing a speed-changing sprocket that can change the diameter of a bicycle sprocket, which is not only theoretically feasible, but also actually possible to achieve such a speed-changing sprocket. Summary of the invention

[0007] The task of the present invention is to provide a speed-changing sprocket, in which the sprocket is made into a circular open rack, and the deformation property of the material is used to change the diameter of the circle, so that a sprocket has two different diameters, so that speed change can be achieved by changing the sprocket diameter rather than by changing the sprocket, thereby solving the problems existing in the above-mentioned prior art.

[0008] The technical solution of the present invention is as follows:

[0009] A speed-changing sprocket comprises a rack, a sprocket fixing plate, a guide rail, a ratchet, an overrunning clutch, an adjusting rod, an adjusting screw and a screw;

[0010] The sprocket fixing plate is circular and is provided with a plurality of elliptical holes near the outer ring of the sprocket fixing plate. A circular rack with a variable opening diameter is movably installed on the periphery of the sprocket fixing plate. A plurality of rack protrusions are provided on the inner surface of the rack. Each rack protrusion is movably installed at the position of the elliptical hole of the sprocket fixing plate by a screw, and the screw can slide in the elliptical hole.

[0011] The guide rail, adjusting rod and adjusting screw are arranged on the sprocket fixing plate, the guide rail is elliptical and arranged at the middle circle of the sprocket fixing plate, the two adjusting rods are forked, the forked ends of the two adjusting rods are respectively connected to the screws arranged in the elliptical hole at the opening of the rack, and the crossed ends of the two adjusting rods are connected to the adjusting screw; one end of the adjusting screw is inserted into the elliptical hole at the intersection of the two adjusting rods arranged on the sprocket fixing plate, and the other end of the adjusting screw is inserted into the guide rail and moves along the guide rail; when the adjusting screw moves to the left, the adjusting rod is pulled and the screw is driven to move inward along the elliptical hole, and the two end faces of the rack are close to reduce the diameter of the rack, and when the adjusting screw moves to the right, the two end faces of the rack are separated and the screw is driven to move outward in the elliptical hole to increase the diameter of the rack;

[0012] The rotating shaft of the pawl is installed on the sprocket fixing plate, and the overrunning clutch is arranged at the center of the guide rail. When the sprocket rotates, the guide rail, the adjusting screw and the sprocket are driven to rotate together through the pawl. The diameter of the sprocket remains unchanged during riding. When pedaling backwards, the sprocket reverses and drives the adjusting screw to rotate together. Under the action of the overrunning clutch, the guide rail does not rotate, and the adjusting screw moves relatively in the guide rail. The guide rail drives the adjusting screw to move radially along the sprocket fixing plate in the elliptical hole, thereby changing the diameter of the sprocket.

[0013] According to a speed-changing sprocket of the present invention, the sprocket is made into a circular open rack, and the deformation property of the material is used to change the diameter of the circle, so that one sprocket has two different diameters, so that the speed of the bicycle can be changed by changing the sprocket diameter rather than by changing the sprocket.

[0014] The speed-changing sprocket of the present invention utilizes the deformation of materials to change the diameter of the sprocket. An open circular rack with a variable diameter is movably mounted on a circular fixed plate to form a sprocket with a variable diameter. Two adjusting rods, an adjusting screw and a guide rail are used to adjust the diameter of the sprocket. When riding, the adjusting screw is moved in the guide rail by pedaling backwards, thereby changing the diameter of the sprocket.

[0015] The speed change sprocket of the present invention is not only feasible in theory, but also can be manufactured in practical applications, so that the speed change system has a simple and practical structure and is convenient for speed change. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1It is a structural schematic diagram of a speed-changing sprocket of the present invention.

[0017] Figure 2 It is a structural schematic diagram of the sprocket fixing plate in the speed change sprocket.

[0018] Figure 3 It is an enlarged schematic diagram of the guide rail, adjusting rod and adjusting screw in the speed change sprocket.

[0019] Figure 4 It is a schematic diagram of the structure of a 37-tooth speed change sprocket of the present invention.

[0020] Figure 5 Yes Figure 4 Schematic diagram of the speed change sprocket structure from 37 teeth to 36 teeth.

[0021] Figure 6 Yes Figure 4 Schematic diagram of the speed change sprocket structure from 37 teeth to 38 teeth.

[0022] Reference numerals:

[0023] 1 is a rack, 2 is a sprocket fixing plate, 3 is a guide rail, 4 is a ratchet, 5 is an overrunning clutch, 6 is an adjusting rod, 7 is an adjusting screw, 8 is a screw, and 11 is a protruding portion of the rack. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0025] See also Figures 1 to 3 The present invention provides a speed-changing sprocket, which is mainly composed of a rack 1, a sprocket fixing plate 2, a guide rail 3, a pawl 4, an overrunning clutch 5, an adjusting rod 6, an adjusting screw 7 and a screw 8.

[0026] The sprocket fixing plate 2 is circular, and a plurality of elliptical holes are arranged near the outer ring of the sprocket fixing plate 2. An open circular rack 1 with a variable diameter is movably installed on the periphery of the sprocket fixing plate 2. A plurality of rack protrusions 11 are arranged on the inner surface of the rack 1. Each rack protrusion 11 is movably installed at the position of the elliptical hole of the sprocket fixing plate 2 by means of a screw 8, and the screw 8 can slide in the elliptical hole.

[0027] The guide rail 3, the adjusting rod 6 and the adjusting screw 7 are arranged on the sprocket fixing plate 2. The diameter of the sprocket can be adjusted by using two adjusting rods 6, one adjusting screw 7 and one guide rail 3. The guide rail 3 is elliptical and is arranged at the middle circle of the sprocket fixing plate 2. The two adjusting rods 6 are forked, and the forked ends of the two adjusting rods 6 are respectively connected to the screws 8 located at the opening of the rack 1, and the screws 8 are arranged in the elliptical holes; the crossed ends of the two adjusting rods 6 are connected to the adjusting screw 7. One end of the adjusting screw 7 is inserted into the elliptical hole on the sprocket fixing plate 2, and the elliptical hole is arranged at the intersection of the two adjusting rods 6; the other end of the adjusting screw 7 is inserted into the guide rail 3 and moves along the guide rail.

[0028] When the adjusting screw 7 moves to the left, the adjusting rod 6 is pulled and the screw 8 is driven to move inward along the elliptical hole, at which time the two end faces of the rack 1 are close to each other and the rack diameter is reduced. When the adjusting screw 7 moves to the right, the two end faces of the rack 1 are separated, driving the screw 8 to move outward in the elliptical hole, and at this time the rack diameter is increased.

[0029] The rotating shaft of the ratchet 4 is mounted on the sprocket fixing plate 2. The overrunning clutch 5 is arranged at the center of the guide rail 3. When the sprocket rotates, the guide rail 3, the adjusting screw 7 and the sprocket are driven to rotate together through the ratchet 4, and the diameter of the sprocket remains unchanged during riding; when the pedal is reversed, the sprocket reverses and drives the adjusting screw 7 to rotate together, and the guide rail 3 does not rotate under the action of the overrunning clutch 5, and the adjusting screw 7 moves relatively in the guide rail 3, and the guide rail 3 drives the adjusting screw 7 to move radially in the elliptical hole of the sprocket fixing plate 2, thereby changing the diameter of the sprocket.

[0030] See also Figure 4 , Figure 5 and Figure 6 , the three figures show the rack profiles of three sprockets of different diameters for the same circular open rack with 36 teeth. Figure 4 The rack shown is a non-deformed rack with a diameter corresponding to 37 teeth and a notched rack. Figure 5 The rack in the middle is compressed, the gap is just closed, and the diameter is a rack with 36 teeth. Figure 6 Indicates that the rack has deformed and the diameter has increased to the equivalent of an open rack with 38 teeth. Figure 5 The diameter of the sprocket when the rack is shown is the same as that of a normal sprocket. As for the diameter of the rack equivalent to 38 teeth, it is different from that of a normal 38-tooth sprocket because it only has 36 teeth, so only 36 pitches. In order to mesh accurately with the chain, the total length of the pitch of these 36 teeth should be equal to the length of the 38 pitches of a normal 38-tooth sprocket. Therefore, the distance between the centers of two adjacent tooth grooves at the notch should be equal to the length of three normal sprocket pitches. This means that its diameter is different from the diameter of a normal 38-tooth sprocket.

[0031] like Figure 1 As shown in the figure, the eight protrusions 11 on the rack 1 are used to movably mount the rack 1 on the sprocket fixing plate 2 by screws 8, so that the rack 1 becomes a sprocket with a certain strength. Since the rack 1 is installed at different positions, the rack 1 can be made into a sprocket with 36 teeth and 38 teeth respectively.

[0032] like Figure 3 As shown in , nine elliptical holes are provided on the sprocket fixing plate 2. The eight elliptical holes near the outside of the sprocket fixing plate 2 correspond to the eight protrusions 11 on the rack 1. The rack 1 and the sprocket fixing plate 2 are movably mounted by screws 8. The so-called "movably mounted" means that the screws are not fixed to the fixing plate and can slide in the hole. When the rack 1 is deformed and pushes all eight screws 8 to slide to the outermost end of the hole and fits tightly against the hole wall, the diameter of the sprocket is the largest, corresponding to a sprocket with 38 teeth. Conversely, when the screw 8 is positioned close to the innermost part of the hole, the diameter of the sprocket is the smallest, and this is a sprocket with 36 teeth. Therefore, the screws are not fixed, but pressed.

[0033] To adjust the positions of the eight screws 8 in the eight elliptical holes, the ninth elliptical hole needs to be used, which is arranged at the intersection of the two adjusting rods 6. The adjustment is completed by the two adjusting rods 6, an adjusting screw 7 and a guide rail 3.

[0034] The two adjusting rods 6 are in a forked shape, and one end of the forked ends of the two adjusting rods 6 is respectively connected to the screws 8 at the opening of the rack 1, and the other ends of the two adjusting rods 6 are connected to the adjusting screw 7. One end of the adjusting screw 7 is inserted into the ninth elliptical hole on the sprocket fixing plate 2, and the other end of the adjusting screw 7 is inserted into the guide rail 3, and can move along the guide rail 3. When the adjusting screw 7 moves to the left, the adjusting rod 6 is pulled, and the eight screws 8 are driven to move inward along the eight elliptical holes, and the two end faces of the rack 1 are close, and the diameter of the rack 1 is reduced. When the adjusting screw 7 moves to the right, the two end faces of the rack 1 are separated, driving the eight screws 8 to move outward in the eight elliptical holes, and the diameter of the rack 1 is increased.

[0035] like Figure 3 As shown in , the adjusting screw 7 is at the leftmost end of the elliptical hole, at which time the two end faces of the rack 1 are just in contact, and the diameter of the rack 1 is the smallest, corresponding to a sprocket with 36 teeth. When the adjusting screw 7 moves to the rightmost end of the elliptical hole, it is equivalent to a sprocket with 38 teeth.

[0036] The movement of the adjusting screw 7 is driven by the guide rail 3. As long as there is relative movement between the adjusting screw 7 and the guide rail 3, the guide rail 3 will push the adjusting screw 7 to move in the ninth elliptical hole. The adjustment process is as follows: the rotating shaft of the ratchet 4 is installed on the sprocket fixing plate 2. When the sprocket rotates, the ratchet 4 drives the guide rail 3, the adjusting screw 7 and the sprocket to rotate together. At this time, the adjusting screw 7 and the guide rail 3 are relatively stationary, so the diameter of the sprocket does not change when the bicycle is riding. When the diameter of the sprocket needs to be changed, just pedal the bicycle backwards. When pedaling backwards, the sprocket rotates backwards, driving the adjusting screw 7 to rotate together. Due to the effect of the overrunning clutch 5, the guide rail 3 does not rotate at this time, so the adjusting screw 7 produces relative movement in the guide rail 3, and the guide rail 3 drives the adjusting screw 7 to move radially along the sprocket fixing plate 2 in the ninth elliptical hole, thereby changing the diameter of the sprocket.

[0037] like Figure 1 As shown in , the guide rail 3 is approximately elliptical. When the adjusting screw 7 is located at the minor axis of the ellipse of the guide rail 3, the adjusting screw 7 is close to the left side of the ninth elliptical hole of the sprocket fixing plate 2, and the corresponding sprocket is a sprocket with 36 teeth. When the foot is stepped backwards by 90°, since the guide rail 3 does not move, the adjusting screw 7 rotates to the major axis of the ellipse and moves to the rightmost end of the ninth elliptical hole at the same time, and the sprocket is equivalent to a sprocket with 38 teeth. When the foot is stepped backwards by 90° again, the adjusting screw 7 returns to the minor axis of the guide rail 3, and the sprocket becomes a sprocket with 36 teeth again.

[0038] The specific number of teeth and the variation of the rack of the speed-changing sprocket of the present invention can be designed as required.

[0039] In summary, the speed-changing sprocket of the present invention utilizes the deformation of the material to change the diameter of the sprocket, and an open circular rack with a variable diameter is movably mounted on a circular fixed plate to form a sprocket with a variable diameter, and then two adjustment rods, an adjustment screw and a guide rail are used to adjust the diameter of the sprocket. When riding, the adjustment screw is moved in the guide rail by pedaling backwards, thereby changing the diameter of the sprocket. The structure is simple, practical, and convenient for speed change.

[0040] Of course, those skilled in the art should realize that the above embodiments are only used to illustrate the present invention, and are not used to limit the present invention. As long as they are within the essential spirit of the present invention and within the scope of changing the number of sprocket teeth by deforming the material, any changes or modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims

1. A speed change sprocket, characterized in that: It comprises a rack (1), a sprocket fixing plate (2), a guide rail (3), a ratchet (4), an overrunning clutch (5), an adjusting rod (6), an adjusting screw (7) and a screw (8); The sprocket fixing plate (2) is circular and is provided with a plurality of elliptical holes near the outer ring of the sprocket fixing plate. A circular rack (1) with a variable opening diameter is movably mounted on the periphery of the sprocket fixing plate (2). The inner surface of the rack (1) is provided with a plurality of rack protrusions (11). Each rack protrusion (11) is movably mounted at the position of the elliptical hole of the sprocket fixing plate (2) by means of a screw (8), and the screw (8) is slidable in the elliptical hole. The guide rail (3), the adjusting rod (6) and the adjusting screw (7) are arranged on the sprocket fixing plate (2); the guide rail (3) is elliptical and is arranged at the middle circle of the sprocket fixing plate (2); the two adjusting rods (6) are forked; one end of the forked adjusting rods (6) is respectively connected to a screw (8) arranged in an elliptical hole at the opening of the rack (1); one end of the two adjusting rods (6) is connected to the adjusting screw (7); one end of the adjusting screw (7) is inserted into the sprocket fixing plate The other end of the adjusting screw (7) is inserted into the guide rail (3) and moves along the guide rail in the elliptical hole provided on the plate (2) and located at the intersection of the two adjusting rods (6); when the adjusting screw (7) moves to the left, the adjusting rod (6) is pulled and the screw (8) is driven to move inward along the elliptical hole, and the two end faces of the rack (1) are brought close to reduce the diameter of the rack; when the adjusting screw (7) moves to the right, the two end faces of the rack (1) are separated and the screw (8) is driven to move outward in the elliptical hole to increase the diameter of the rack; The rotating shaft of the ratchet (4) is mounted on the sprocket fixing plate (2), and the overrunning clutch (5) is arranged at the center of the guide rail (3). When the sprocket rotates, the ratchet (4) drives the guide rail (3), the adjusting screw (7) and the sprocket to rotate together. The diameter of the sprocket remains unchanged during riding. When pedaling backward, the sprocket rotates backward and drives the adjusting screw (7) to rotate together. Under the action of the overrunning clutch (5), the guide rail (3) does not rotate, and the adjusting screw (7) moves relatively in the guide rail (3). The guide rail (3) drives the adjusting screw (7) to move in the radial direction of the sprocket fixing plate (2) in the elliptical hole, thereby changing the diameter of the sprocket.

Images