Purely mechanical continuously variable transmission for variable-cycle bidirectional drive device for bicycle

Abstract

A purely mechanical continuously variable transmission for a variable-cycle bidirectional drive device for a bicycle. Round tubes (2) having slots at both ends are fixed to a bicycle frame (1), and the inner sides of two gear discs (5, 6) are provided with protrusions embedded in the slots of the round tubes (2), so that the gear discs can slide axially along the round tubes (2). A circular support plate (3) supports a central shaft frame (4) to rotate inside, two freely rotating screw rods (9, 10) are provided in the central shaft frame (4), small sprockets (11, 12) and small gears (8, 7) are respectively fixed on the screw rods (9, 10), a chain (13) connects the two small sprockets (11, 12) so that the two screw rods (9, 10) always rotate in the same direction, and the two screw rods (9, 10) are each provided with a nut (14, 15) fixed to a sliding block. When rotating counterclockwise, the central shaft frame (4) pushes the gear discs (5, 6) to mesh with the small gears (8, 7), driving the nuts (15, 14) to approach the small gears (8, 7); in this case, traction rods on both sides synchronously extend outwards or retract inwards.

Description

Pure mechanical stepless transmission for bicycle variable cycle bidirectional drive device TECHNICAL FIELD

[0001] The present application relates to a pure mechanical stepless transmission for bicycle variable cycle bidirectional drive device. BACKGROUND

[0002] PCT / CN2021 / 079460 discloses a bicycle variable cycle bidirectional drive device, which can realize variable speed function through the sliding of two traction rods along the radial direction of the middle shaft. TECHNICAL PROBLEM

[0003] There is a need for a pure mechanical device that can control the synchronous sliding of two traction rods rotating with the middle shaft with the force of the hand. TECHNICAL SOLUTION

[0004] Embodiment one

[0005] This embodiment includes two notched circular tubes fixed to the frame, two toothed discs with protrusions embedded in the notches of the circular tubes, and the toothed discs can slide axially along the circular tubes. There are two screw rods with opposite screw directions in the middle shaft frame, and each screw rod is fixed with a sprocket. The ring chain ensures that the two sprockets always rotate in the same direction. Each screw rod has a nut fixed with a sliding block and a traction rod, and the other end of the screw rod is fixed with a gear that can engage with the toothed disc.

[0006] Try mode two

[0007] This embodiment includes two notched circular tubes fixed to the frame, two toothed discs with protrusions embedded in the notches of the circular tubes, and the toothed discs can slide axially along the circular tubes. There is a shaft in the middle shaft frame, and the shaft has two sections of worm gears with opposite screw directions in the middle. The two sections of worm gears drive two worm gears on both sides to rotate in the same direction, and each worm gear drives a rack fixed with a traction rod to move in the opposite direction. The shaft is fixed with a gear that can engage with the toothed disc. Beneficial effects

[0008] A part of the power from the bicycle itself drives the sliding of the traction rods, and both hands only need to push the toothed disc to engage with the pinion to drive the synchronous sliding of the two traction rods. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is scheme one

[0010] Figure 2 is scheme two

[0011] Figure 3 is a view of scheme two with hidden parts Best embodiment of the present application

[0012] Two ends of the round pipe (2) with notches are fixed on the frame (1), the inner side of the two toothed discs (5, 6) has protrusions embedded in the notches of the round pipe (2), the two toothed discs (5, 6) can slide along the round pipe (2) in the axial direction. The circular support plate (3) supports the rotation of the central shaft frame (4) inside, the central shaft frame (4) has two freely rotating screw rods (9, 10) inside, the screw rod (9) has a small chain wheel (11) and a pinion (8) fixed on it respectively, the screw rod (10) has a small chain wheel (12) and a pinion (7) fixed on it, the chain (13) links the two small chain wheels (11, 12) to make the two screw rods (9, 10) always rotate in the same direction. Each of the two screw rods has a nut (14, 15) fixed with a sliding block. Assuming that the counterclockwise direction is the positive direction of riding, the rotation direction of the central shaft frame (4) at this time, the screw rod (9) is a positive thread, and the screw rod (10) is a reverse thread. When the central shaft frame (4) rotates counterclockwise, the toothed disc (5) is engaged with the pinion (8), since the toothed disc (5) cannot rotate, the pinion (8) can only rotate, and the nut (15) is pushed to the pinion (8), at this time, the two side traction rods will synchronously stretch outwards, when the nut (15) is too close to the pinion (8), the assembly (16) fixed on the nut (15) will extrude the edge of the toothed disc (5) to push it out of contact with the pinion (8). When the central shaft frame (4) rotates counterclockwise, the toothed disc (6) is engaged with the pinion (7), since the toothed disc (6) cannot rotate, the pinion (7) can only rotate, and the nut (14) is pushed to the pinion (7), at this time, the two side traction rods will synchronously contract inwards, when the nut (14) is too close to the pinion (7), the assembly (17) fixed on the nut (14) will extrude the edge of the toothed disc (6) to push it out of contact with the pinion (7). Since the bicycle variable cycle bidirectional driving device supports the reverse rotation of the central shaft frame to drive the bicycle forward, when the central shaft frame (4) rotates clockwise, starting the variable speed function will cause the function to be reversed and the self-protection device (16, 17) to be invalid, the reverse driving will cause the central shaft frame to be locked or even the parts to be damaged. In order to avoid this situation, a set of ratchet devices is added inside the pinions (7, 8) respectively, when the central shaft frame (4) rotates clockwise, the rotation of the pinions (7, 8) will not drive the two screw rods (10, 9). Embodiments of the invention

[0013] Embodiment one

[0014] Two ends of the pipe (2) are fixed on the frame (1), the two toothed discs (5, 6) have protrusions embedded in the notches of the pipe (2), and the two toothed discs (5, 6) can slide along the pipe (2) in the axial direction. The circular support plate (3) supports the rotation of the central shaft frame (4) inside, the central shaft frame (4) has two freely rotating screw rods (9, 10), the screw rod (9) has a small chain wheel (11) and a pinion (8) fixed on it, the screw rod (10) has a small chain wheel (12) and a pinion (7) fixed on it, and the chain (13) links the two small chain wheels (11, 12) to make the two screw rods (9, 10) always rotate in the same direction. Each of the two screw rods has a nut (14, 15) fixed with a sliding block. Assuming that the counterclockwise direction is the positive direction of riding, the rotation direction of the central shaft frame (4) at this time, the screw rod (9) is a positive thread, and the screw rod (10) is a reverse thread. When the central shaft frame (4) rotates counterclockwise, it pushes the toothed disc (5) to engage with the pinion (8), and since the toothed disc (5) cannot rotate, the pinion (8) can only rotate, pushing the nut (15) to move closer to the pinion (8), at this time the two side traction rods will synchronously stretch outwards, when the nut (15) is too close to the pinion (8), the assembly (16) fixed on the nut (15) will extrude the edge of the toothed disc (5) to push it out of contact with the pinion (8). When the central shaft frame (4) rotates counterclockwise, it pushes the toothed disc (6) to engage with the pinion (7), and since the toothed disc (6) cannot rotate, the pinion (7) can only rotate, pushing the nut (14) to move closer to the pinion (7), at this time the two side traction rods will synchronously contract inward, when the nut (14) is too close to the pinion (7), the assembly (17) fixed on the nut (14) will extrude the edge of the toothed disc (6) to push it out of contact with the pinion (7). Since the bicycle variable cycle bidirectional driving device supports the reverse rotation of the central shaft frame to drive the bicycle forward, when the central shaft frame (4) rotates clockwise, starting the variable speed function will cause the function to be reversed and the self-protection device (16, 17) to be invalid, and the reverse driving will cause the central shaft frame to be locked or even the parts to be damaged. In order to avoid this situation, a set of ratchet devices is added inside each pinion (7, 8), and when the central shaft frame (4) rotates clockwise, the rotation of the pinion (7, 8) will not be able to drive the two screw rods (10, 9).

[0015] Embodiment two

[0016] Two notched round tubes (102, 103) are fixed on both sides of the frame (101), two toothed discs (111, 110) have protrusions embedded in the notches of the two round tubes (102, 103) respectively, and the two toothed discs (111, 110) can slide axially along the round tubes (102, 103). The shaft (106) in the central shaft frame (105) has two opposite direction threaded worms, which respectively drive the two worm gears (108, 109) on both sides to rotate in the same direction, the two worm gears (108, 109) respectively drive the toothed racks on the outside to move in opposite directions, and the shaft is fixed with a gear (107) that can mesh with the toothed disc. The circular support plate (104) supports the rotation of the central shaft frame (105) inside. Assuming that the counterclockwise direction is the positive direction of riding, when the toothed disc (110) meshes with the gear (107) and the two worms on the shaft (106) simultaneously drive the two worm gears (108, 109) to rotate clockwise, the toothed racks on both sides shrink inward at this time. When the rotation amplitude of the worm gear (108) exceeds the range, (112) rotating with the worm gear (108) will push the toothed disc (110) out of contact with the gear (107). When the toothed disc (111) meshes with the gear (107), the two worms on the shaft (106) simultaneously drive the two worm gears (108, 109) to rotate counterclockwise, and at this time the toothed racks on both sides expand outward. When the rotation amplitude of the worm gear (109) exceeds the range, (113) rotating with the worm gear (109) will push the lower end of (114) to move inward, and the upper end of (114) will push the toothed disc (111) out of contact with the gear (107). Since the bicycle variable cycle bidirectional driving device supports the reverse rotation of the central shaft frame to drive the bicycle forward, starting the variable speed function when the central shaft frame (105) rotates clockwise will cause the function to be reversed and the self-protection device (112, 113, 114) to fail, and the reverse drive will cause the central shaft frame to be locked or even the parts to be damaged. To avoid this situation, a set of ratchet devices is added to each of the toothed discs (111, 110) inside. When the central shaft frame (105) rotates clockwise, the small gear (107) will drive the two toothed discs (111, 110) to rotate clockwise together, and the small gear (107) will not rotate. Industrial applicability

[0017] Only a small number of simple parts are used, and the efficiency of scheme one is higher, and the key parts are all inside, which is easier to seal. The volume of scheme two is smaller. Both schemes have perfect self-protection mechanisms. Free content of sequence listing

[0018] [Deleted, Rule 91, 09.09.2025]

Claims

1. Two notched pipes (2) are fixed on the frame (1), two toothed discs (5, 6) have protrusions embedded in the notches of the pipes (2), and the toothed discs (5, 6) can slide along the pipes (2) in the axial direction. A circular support plate (3) supports the rotation of the central shaft frame (4) inside, and the central shaft frame (4) has two freely rotating screws (9, 10) inside. Each screw (9) has a small chain wheel (11) and a pinion (8) fixed on it, and each screw (10) has a small chain wheel (12) and a pinion (7) fixed on it. A chain (13) links the two small chain wheels (11, 12) to make the two screws (9, 10) always rotate in the same direction. Each screw has a nut (14, 15) fixed with a sliding block.

2. Two notched pipes (102, 103) are fixed on both sides of the frame (101), two toothed discs (111, 110) have protrusions embedded in the notches of the pipes (102, 103), and the toothed discs (111, 110) can slide along the pipes (102, 103) in the axial direction. The central shaft frame (105) has a shaft (106) inside, and the shaft has two opposite direction helical gears in the middle, which drive two helical gears (108, 109) on both sides to rotate in the same direction. The shaft has a gear (107) fixed on it that can engage with the toothed disc.

3. When the nut (15) is too close to the pinion (8), the assembly (16) fixed on the nut (15) will press the edge of the toothed disc (5) to push it out of contact with the pinion (8). When the nut (14) is too close to the pinion (7), the assembly (17) fixed on the nut (14) will press the edge of the toothed disc (6) to push it out of contact with the pinion (7).

4. Each pinion (7, 8) has a set of ratchet devices inside, and when the central shaft frame (4) rotates in the opposite direction, the self-rotation of the pinion (7, 8) will not be able to drive the two screws (10, 9).

5. When the helical gear (108) rotates beyond the range, the long strip (112) rotating with the helical gear (108) will push the toothed disc (110) out of contact with the gear (107). When the helical gear (109) rotates beyond the range, the protrusion (113) rotating with the helical gear (109) will push the lower end of the long strip (114) to move inward, and the upper end of (114) will move outward to push the toothed disc (111) out of contact with the gear (107).

6. Each toothed disc (111, 110) has a set of ratchet devices inside, and when the central shaft frame (105) rotates in the opposite direction, the pinion (107) will drive the two toothed discs (111, 110) to rotate in the opposite direction, but the pinion (107) will not rotate.

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