Gearbox capable of shifting up and down under heavy load and bicycle with gearbox

Abstract

The invention relates to the technical field of transmission systems, in particular to a gearbox capable of shifting up and down under heavy loads and a bicycle with the gearbox, the gearbox comprises a box body, a gear shifting control system, a main shaft, an auxiliary shaft, an M-gear main shaft gear, an M-gear auxiliary shaft gear and a ratchet wheel, and the gear shifting control system comprises an elastic shifting fork mechanism, a gear withdrawing piece and a gear shifting driving mechanism; the gear shifting driving mechanism comprises a gear shifting drumstick mechanism and a drumstick driving mechanism; the gear shifting drum rod mechanism comprises a shifting fork gear shifting drum and a flexible gear-withdrawing gear shifting drum; according to the gear shifting device, load unloading and gear shifting are not needed in the process that a gearbox is shifted from a high gear to a low gear, for example, a bicycle can be shifted without stopping pedaling, gear shifting and gear shifting are smooth when the gearbox is loaded, and the risk of bicycle falling caused by the fact that forward balance of the bicycle is affected by a force unloading mode of stopping pedaling and gear shifting during climbing is avoided; and the riding safety and experience feeling are greatly improved. Meanwhile, the abrasion and damage risks of the gearbox are reduced, the service life is prolonged, and the failure rate and the use cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of transmission systems, in particular to a gearbox capable of shifting up and down under heavy loads and a bicycle thereof. Background Art

[0002] In the transmission system of the gearbox, in order to realize the transmission change mechanism between different gear pairs of the gearbox, a gear shift control system is needed to shift gears. Figure 1 As shown, in existing transmissions, the shift control system's pawl is located within the countershaft. To shift gears, a cable is manually pulled to push the pawl back into the countershaft. When the transmission is loaded and a gear change is required, the pawl cannot be pulled out, forcing it to disengage. This requires stopping the pedals and forcibly pulling the pawl out of engagement, which carries the risk of the cable breaking or the pawl deforming and becoming stuck.

[0003] Based on the above-mentioned deficiencies of the gearbox, it is urgent to provide a solution to overcome the above-mentioned technical problems. Summary of the Invention

[0004] The present invention addresses the shortcomings of the prior art by providing a transmission and bicycle capable of shifting up and down even under heavy loads. This allows for smooth shifting when the transmission is loaded, avoiding the risk of a fall caused by the need to stop and pedal to shift downhill, which can affect the bicycle's forward balance. This significantly improves riding safety and the riding experience. It also reduces the risk of transmission wear and damage, prolongs its service life, lowers the failure rate, and reduces operating costs. It effectively avoids the problems of prior transmissions, such as the need to stop and pedal to shift down, cable breakage, or pawl deformation and jamming.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention provides a transmission capable of shifting up and down under heavy loads, comprising a transmission housing and a shift control system; a main shaft and a countershaft are mounted in parallel within the transmission housing; the main shaft is mounted with an M-position mainshaft gear; the countershaft is mounted with an M-position countershaft gear meshing with the M-position mainshaft gear; and a ratchet is slidably mounted on the main shaft or the countershaft to mesh with the M-position mainshaft gear or the M-position countershaft gear.

[0007] The ratchet is provided with an axially protruding backshift protrusion; the shift control system includes an elastic fork mechanism, a backshift member, and a shift drive mechanism for driving the elastic fork mechanism and the backshift member to move, and the ratchet is drivingly connected to the elastic fork mechanism;

[0008] The gear shift driving mechanism includes a gear shift drum stick mechanism and a drum stick driving mechanism for driving the gear shift drum stick mechanism to rotate;

[0009] The shift drum rod mechanism includes a shift fork shift drum and a flexible reverse shift drum; the elastic shift fork mechanism is drivingly connected to the shift fork shift drum, and the reverse member is drivingly connected to the flexible reverse shift drum;

[0010] When shifting from low gear to M gear, the drumstick driving mechanism drives the shift fork shift drum and the flexible reverse shift drum to rotate, and the shift fork shift drum and the flexible reverse shift drum respectively drive the elastic shift fork mechanism and the reverse gear member to move from a preset position to the M gear main shaft gear or the M gear countershaft gear, so that the elastic shift fork mechanism drives the ratchet to engage with the M gear main shaft gear or the M gear countershaft gear, thereby realizing the transmission upshift;

[0011] When changing from M gear to low gear, the drum stick driving mechanism drives the shift fork shift drum and the flexible return shift drum to rotate, so that the shift fork shift drum and the flexible return shift drum respectively drive the elastic shift fork mechanism and the return member away from the M gear mainshaft gear or the M gear countershaft gear to the preset position. During the continued rotation of the main shaft or countershaft, when the return member abuts against one side of the return protrusion of the ratchet, the return member abuts against the return protrusion to make the ratchet exit the M gear mainshaft gear or the M gear countershaft gear, and the elastic shift fork mechanism pulls the ratchet back to the preset position to achieve gearbox downshifting; when the return member abuts against the top of the return protrusion, the shift fork shift drum continues to rotate to drive the elastic shift fork mechanism to move. After the conflict between the return member and the return protrusion disappears, the return member moves under the drive of the flexible return shift drum until it returns to the synchronous state with the elastic shift fork mechanism and moves to the preset position.

[0012] Among them, the shift fork shift drum includes a shift fork drum rod and a shift fork shift groove arranged on the shift fork drum rod; the elastic shift fork mechanism is provided with a shift fork shift guide pin, and the shift fork shift pin is arranged in the shift fork shift groove.

[0013] Preferably, the flexible reverse gear shift drum includes a first gear shift sleeve and a first torsion spring, wherein the first gear shift sleeve is mounted on the shift fork drum rod; the first torsion spring is sleeved on the shift fork drum rod, one end of the first torsion spring abuts against the shift fork drum rod, and the other end of the first torsion spring abuts against the first gear shift sleeve;

[0014] The first shift sleeve is provided with a first shift-return groove, the shift-return member is provided with a shift-return guide pin, and the shift-return guide pin is provided in the first shift-return groove.

[0015] Furthermore, a first abutment platform is provided in the axial direction of the shift fork drum rod, and a second abutment platform is provided in the axial direction of the first shift sleeve. One end of the first torsion spring abuts against the first abutment platform, and the other end of the first torsion spring abuts against the second abutment platform.

[0016] When shifting from the low gear to the M gear, the first abutment platform abuts against the second abutment platform, so that the shift fork drum stick pushes the first shift sleeve to rotate together;

[0017] When shifting from the M gear to the low gear, the first abutment platform squeezes the first torsion spring, and the first torsion spring squeezes the second abutment platform, so that the shift fork drum stick pushes the first shift sleeve to rotate through the first torsion spring.

[0018] In another embodiment, the flexible reverse gear shift drum includes a reverse gear shift drum rod, a second shift sleeve and a second torsion spring mounted on the reverse gear shift drum rod.

[0019] One end of the second torsion spring abuts against the reverse gear shift drum rod, and the other end of the second torsion spring abuts against the second gear shift sleeve;

[0020] The second shift sleeve is provided with a second shift-return groove; the shift-return member is provided with a shift-return guide pin, and the shift-return guide pin is provided in the second shift-return groove.

[0021] Furthermore, a third abutment is provided in the axial direction of the reverse gear shift drum rod, and a fourth abutment is provided in the axial direction of the second gear shift sleeve. One end of the second torsion spring abuts against the third abutment, and the other end of the second torsion spring abuts against the fourth abutment.

[0022] When shifting from the low gear to the M gear, the third abutment abuts against the fourth abutment, so that the reverse gear shift drum rod pushes the second gear shift sleeve to rotate;

[0023] When shifting from the M gear to the low gear, the third abutment platform squeezes the second torsion spring, and the second torsion spring squeezes the fourth abutment platform, so that the reverse gear shift drum rod pushes the second gear shift sleeve to rotate through the second torsion spring.

[0024] Preferably, there are two retraction protrusions, which are arranged on both sides of the ratchet, and the retraction member is located between the two retraction protrusions;

[0025] The shift control system is provided with a shift guide rod, and the elastic fork mechanism and / or the backshift member are slidably mounted on the shift guide rod;

[0026] The ratchet is provided with a neutral positioning hole, and the main shaft is provided with an elastic positioning bead structure. When the ratchet is in neutral, the positioning beads of the elastic positioning bead structure are clamped into the neutral positioning hole.

[0027] The transmission capable of shifting up and down under heavy load is further provided with an anti-neutral gear mechanism, the anti-neutral gear mechanism comprising at least one ratchet member installed in a first gear countershaft gear on the countershaft and a reset member for resetting the ratchet member;

[0028] The pawl member is located in the first gear countershaft gear; when in use, when the countershaft drives the pawl member to rotate, the pawl member slips in the first gear countershaft gear; when the main shaft drives the first gear mainshaft gear and the first gear countershaft gear to rotate, the pawl member engages with the first gear countershaft gear, so that the pawl member drives the countershaft to rotate.

[0029] Furthermore, the secondary shaft is provided with a pawl groove, the pawl member is provided with a mounting portion that cooperates with the pawl groove, and the mounting portion is mounted in the pawl groove;

[0030] The pawl member is further provided with a pawl portion, one side of the pawl portion is provided with an arc-shaped sliding surface, and the other side of the pawl portion is provided with an engaging surface;

[0031] The pawl member is provided with a first fixing groove, the secondary shaft is provided with a second fixing groove, the reset member is an annular spring, the reset member is embedded in the first fixing groove and the second fixing groove to install the pawl member on the secondary shaft; the reset member always makes the pawl part of the pawl member tilt up and extend out of the pawl groove

[0032] The present invention also provides a bicycle comprising the above-mentioned transmission case capable of shifting up and down gears even under heavy load.

[0033] Beneficial effects of the present invention:

[0034] This transmission and bicycle capable of shifting up and down under heavy loads, and wherein when shifting from the M gear to a low gear, the retracting member, while the main shaft or countershaft continues to rotate under load, engages the retracting protrusion of the ratchet wheel to cause the ratchet wheel to retract from the M gear main shaft gear or the M gear countershaft gear. The resilient shift fork mechanism then pulls the ratchet wheel back to a preset position, thereby enabling the transmission to shift down from a high gear to a low gear without unloading the load. For example, the bicycle can be downshifted without stopping to pedal, and the circumferential driving force of the shaft rotation under load is effectively utilized to downshift. Compared to existing transmissions that require stopping to pedal to downshift, or are subject to problems such as cable breakage or pawl deformation and jamming, this transmission shifts up and down smoothly under load, avoiding the risk of falling due to the force unloading method of stopping to pedal to downshift when climbing, thereby greatly improving riding safety and riding experience. At the same time, the risk of transmission wear and damage is reduced, the service life is extended, and the failure rate and cost of use are reduced.

[0035] The gear shifting control system of this gearbox adopts a flexible backshift and shift drum to drive the backshift member to move. When the backshift member contacts the top of the backshift protrusion, the shift fork shift drum continues to rotate to drive the elastic shift fork mechanism to move to complete the next gear entry stroke. At this time, the movement of the backshift member and the elastic shift fork mechanism are separated. During the continued rotation of the main shaft or the secondary shaft, after the conflict between the backshift member and the backshift protrusion disappears, the backshift member moves to the preset position driven by the elastic force of the flexible backshift and shift drum, and returns to the synchronous state with the elastic shift fork mechanism, thereby effectively avoiding the backshift member from being stuck when it contacts the top of the backshift protrusion, ensuring smooth downshifting control of the gearbox. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Schematic diagram of the structure of the existing gearbox.

[0037] Figure 2This is a schematic diagram of the three-dimensional structure of the gearbox after the box body is hidden in the first embodiment of the present invention.

[0038] Figure 3 This is another schematic diagram of the three-dimensional structure of the gearbox after the hidden box body in the first embodiment of the present invention.

[0039] Figure 4 Schematic diagram of the three-dimensional structure of the gear shift control system, main shaft and ratchet in embodiment 1 of the present invention.

[0040] Figure 5 Schematic diagram of the decomposed structure of the gear shift control system in embodiment 1 of the present invention.

[0041] Figure 6 Schematic diagram of the exploded structure of the gear-shift drumstick mechanism in the first embodiment of the present invention.

[0042] Figure 7 This is a schematic diagram of the exploded structure of the gearbox after the box is hidden in Example 1 of the present invention.

[0043] Figure 8 for Figure 7 Schematic diagram of the enlarged structure at M in the middle.

[0044] Figure 9 Schematic diagram of the exploded structure of the secondary shaft, the pawl member and the reset member in the first embodiment of the present invention.

[0045] Figure 10 Schematic diagram of the structure of the secondary shaft, the pawl member and the reset member in the first embodiment of the present invention.

[0046] Figure 11 for Figure 10 Schematic diagram of the enlarged cross-section structure at DD in the middle.

[0047] Figure 12 for Figure 10 Schematic diagram of the enlarged cross-section structure at CC in the middle.

[0048] Figure 13 Schematic diagram of the three-dimensional structure of the pawl member and the reset member in the first embodiment of the present invention.

[0049] Figure 14 This is a schematic diagram of the three-dimensional structure of the gearbox after the box body is hidden in the second embodiment of the present invention.

[0050] Figure 15 This is a schematic diagram of the exploded structure of the gearbox with the box hidden in the second embodiment of the present invention.

[0051] Figure 16 Schematic diagram of the exploded structure of the flexible reverse gear shift drum in the second embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the embodiments and the accompanying drawings. The contents mentioned in the embodiments are not intended to limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.

[0053] Example 1.

[0054] refer to Figures 2 to 13 As shown, a transmission capable of shifting up and down under heavy loads includes a transmission housing and a shift control system 6; a main shaft 1 and a countershaft 2 are mounted in parallel within the transmission housing; the main shaft 1 is mounted with an M-position mainshaft gear 3; the countershaft 2 is mounted with an M-position countershaft gear 4 meshing with the M-position mainshaft gear 3; a ratchet 5 is slidably mounted on the main shaft 1 or the countershaft 2 and meshing with the M-position mainshaft gear 3 or the M-position countershaft gear 4;

[0055] The ratchet 5 is provided with an axially protruding back-shifting protrusion 51; the shift control system 6 includes an elastic fork mechanism 61, a back-shifting member 62, and a shift driving mechanism 63 for driving the elastic fork mechanism 61 and the back-shifting member 62 to move; the ratchet 5 is drivingly connected to the elastic fork mechanism 61;

[0056] The gear shift driving mechanism 63 includes a gear shift drum stick mechanism 631 and a drum stick driving mechanism 630 for driving the gear shift drum stick mechanism 631 to rotate;

[0057] The shift drum rod mechanism 631 includes a shift fork shift drum 632 and a flexible reverse shift drum 633; ​​the elastic shift fork mechanism 61 is drivingly connected to the shift fork shift drum 632, and the reverse member 62 is drivingly connected to the flexible reverse shift drum 633;

[0058] When shifting from low gear to M gear, the drumstick driving mechanism 630 drives the shift fork shift drum 632 and the flexible back gear shift drum 633 to rotate, and the shift fork shift drum 632 and the flexible back gear shift drum 633 respectively drive the elastic shift fork mechanism 61 and the back gear 62 to move from a preset position toward the M gear main shaft gear 3 or the M gear countershaft gear 4, so that the elastic shift fork mechanism 61 drives the ratchet 5 to engage with the M gear main shaft gear 3 or the M gear countershaft gear 4, thereby realizing the transmission upshift; at this time, the back gear 62 and the elastic shift fork mechanism 61 slide synchronously and at the same distance but do not work;

[0059] When changing from the M gear to the low gear, the drumstick driving mechanism 630 drives the shift fork shift drum 632 and the flexible backshift shift drum 633 to rotate, so that the shift fork shift drum 632 and the flexible backshift shift drum 633 respectively drive the elastic shift fork mechanism 61 and the backshift member 62 to move away from the M gear main shaft gear 3 or the M gear countershaft gear 4 to a preset position. During the continuous rotation of the main shaft 1 or the countershaft 2, when the backshift member 62 contacts one side of the backshift protrusion 51 of the ratchet 5, the backshift member 62 contacts the backshift protrusion 51. 1 so that the ratchet 5 exits the M-position mainshaft gear 3 or the M-position countershaft gear 4, and the elastic shift fork mechanism 61 pulls the ratchet 5 back to the preset position to achieve downshifting of the transmission; when the return member 62 contacts the top of the return protrusion 51, the shift fork shift drum 632 continues to rotate to drive the elastic shift fork mechanism 61 to move. After the contact between the return member 62 and the return protrusion 51 disappears, the return member 62 is driven by the flexible return shift drum 633 to move to a synchronous state with the elastic shift fork mechanism 61 and move to the preset position.

[0060] In this embodiment, the M gear is not the gear at which the transmission has the lowest speed, such as any gear from second to eighth, and is not the first gear of the transmission. The ratchet 5 can be mounted on the main shaft 1, such as in a five-speed transmission; the ratchet 5 can also be mounted on the countershaft 2, or both the main shaft 1 and the countershaft 2, such as in a seven-speed or eight-speed transmission with high gears.

[0061] This transmission can shift up and down under heavy loads. When shifting from the M gear to the low gear, the retracting member 62 is used to contact the retracting protrusion 51 of the ratchet 5 with the help of the continued rotation of the main shaft 1 or the secondary shaft 2 under the load, so that the ratchet 5 is retracted from the M gear main shaft gear 3 or the M gear secondary shaft gear 4. The elastic fork mechanism 61 is then used to pull the ratchet 5 back to the preset position, thereby realizing the transmission downshifting from high gear to low gear without unloading the load. For example, a bicycle can be downshifted without stopping to pedal, and the load rotation of the circumferential driving force of the shaft rotation under load is effectively utilized to downshift. Compared with existing transmissions that require stopping to pedal to downshift, and have problems such as cable breakage or pawl deformation and jamming, this transmission shifts up and down smoothly under load, avoids the force unloading method of stopping to pedal to downshift when climbing, which affects the forward balance of the bicycle and causes the risk of falling, and greatly improves the riding safety and experience. At the same time, it reduces the risk of wear and damage to the transmission, extends its service life, and reduces the failure rate and cost of use.

[0062] The gear shifting control system of this gearbox adopts a flexible backshift and shift drum 633 to drive the backshift member 62 to move. When the backshift member 62 contacts the top of the backshift protrusion 51, the shift fork shift drum 632 continues to rotate to drive the elastic shift fork mechanism 61 to move to complete the next gear shifting stroke. At this time, the backshift member 62 is separated from the movement of the elastic shift fork mechanism 61. During the continued rotation of the main shaft 1 or the secondary shaft 2, after the conflict between the backshift member 62 and the backshift protrusion 51 disappears, the backshift member 62 is driven by the elastic force of the flexible backshift and shift drum 633 to move to the preset position and return to the synchronous state with the elastic shift fork mechanism 61, thereby effectively avoiding the backshift member 62 from being stuck when it contacts the top of the backshift protrusion 51, ensuring smooth downshifting control of the gearbox.

[0063] In this embodiment, the shift fork shift drum 632 includes a shift fork drum rod 6321 and a shift fork shift slot 6322 disposed in the shift fork drum rod 6321. The elastic shift fork mechanism 61 is provided with a shift fork shift guide pin 611, which is disposed in the shift fork shift slot 6322. During a shift operation, the rotation of the shift fork drum rod 6321 drives the shift fork shift guide pin 611 to move in the shift fork shift slot 6322, thereby causing the elastic shift fork mechanism 61 to drive the ratchet 5 to move, thereby achieving a shift up or down operation.

[0064] In this embodiment, preferably, the flexible reverse gear shift drum 633 includes a first gear shift sleeve 6331 and a first torsion spring 6332, and the first gear shift sleeve 6331 is installed on the shift fork drum rod 6321; the first torsion spring 6332 is sleeved on the shift fork drum rod 6321, one end of the first torsion spring 6332 is in contact with the shift fork drum rod 6321, and the other end of the first torsion spring 6332 is in contact with the first gear shift sleeve 6331; the first gear shift sleeve 6331 is provided with a first reverse gear shift groove 6333, and the reverse gear member 62 is provided with a reverse gear guide pin 621, and the reverse gear guide pin 621 is provided in the first reverse gear shift groove 6333.

[0065] The flexible reverse gear shift drum 633 adopts the flexible structure of the first shift sleeve 6331 and the first torsion spring 6332. When the gearbox shifts up, the shift fork drum rod 6321 drives the first shift sleeve 6331 to rotate together; when the gearbox shifts down, the shift fork drum rod 6321 rotates to abut against the first torsion spring 6332, and the first torsion spring 6332 abuts against the first shift sleeve 6331 to rotate together; when the reverse gear member 62 contacts the top of the reverse gear protrusion 51, the shift fork drum rod 6321 rotates to abut against the first torsion spring 6332, and the first torsion spring 6332 deforms. It does not affect the continued rotation of the shift fork shift drum 632 and drives the elastic shift fork mechanism 61 to move. At this time, the shift fork drum rod 6321 is separated from the first shift sleeve 6331 in rotation, which does not affect the shifting action of the gearbox, thereby avoiding the shift fork shift drum 632 from being stuck; during the continued rotation of the main shaft 1 or the secondary shaft 2, after the abutment between the return member 62 and the return protrusion 51 disappears, the first shift sleeve 6331 rotates under the push of the first torsion spring 6332, thereby driving the return member 62 to move, so that the return member 62 and the elastic shift fork mechanism 61 return to a synchronous state.

[0066] In this embodiment, specifically, a first abutment platform 6323 is axially provided with the shift fork drum rod 6321, a second abutment platform 6334 is axially provided with the first shift sleeve 6331, one end of the first torsion spring 6332 abuts against the first abutment platform 6323, and the other end of the first torsion spring 6332 abuts against the second abutment platform 6334.

[0067] See the instructions attached Figure 6 When the shift fork drum stick 6321 rotates in the B direction, the gearbox changes from the low gear to the M gear, and the first abutment platform 6323 abuts the second abutment platform 6334, so that the shift fork drum stick 6321 pushes the first gear shift sleeve 6331 to rotate together; when the shift fork drum stick 6321 rotates in the A direction, the gearbox changes from the M gear to the low gear, the first abutment platform 6323 squeezes the first torsion spring 6332, and the first torsion spring 6332 squeezes the second abutment platform 6334, so that the shift fork drum stick 6321 pushes the first gear shift sleeve 6331 to rotate through the first torsion spring 6332. The first abutment platform 6323 is provided with a first torsion spring abutment groove 63231 for installing the end of the first torsion spring 6332, and the second abutment platform 6334 is provided with a second torsion spring abutment groove 63341 for installing the end of the first torsion spring 6332. The flexible reverse gear shift drum 633 has an ingenious structural design. After being installed with the shift fork drum rod 6321, the structure is compact and the volume is small, which is conducive to reducing the volume of the gearbox.

[0068] In this embodiment, two retraction protrusions 51 are provided, one on each side of the ratchet 5, and the retraction member 62 is located between the two retraction protrusions 51. A ratchet 5 with double-sided teeth can be provided between the two shift gear sets, and two retraction protrusions 51 can be provided on the ratchet 5, thereby enabling retraction operation of the two shift gear sets. The two sets share the same ratchet 5 and retraction member 62, resulting in a simpler structure and a significantly smaller size of the gearbox.

[0069] In this embodiment, the gear shift control system 6 is provided with a gear shift guide rod 64, and the elastic fork mechanism 61 and / or the return member 62 are slidably installed on the gear shift guide rod 64, which facilitates the installation of the elastic fork mechanism 61 and the return member 62, so that the elastic fork mechanism 61 and the return member 62 move more smoothly when shifting gears.

[0070] In this embodiment, the ratchet 5 is provided with a neutral positioning hole 52, and the main shaft 1 is provided with an elastic positioning bead structure. When the ratchet 5 is in neutral, the positioning bead of the elastic positioning bead structure is snapped into the neutral positioning hole 52. The main shaft 1 is provided with an elastic positioning bead structure. When the ratchet 5 is in neutral, the positioning bead of the elastic positioning bead structure is snapped into the neutral positioning hole 52, thereby preventing the ratchet 5 from shaking and shifting, making it more stable and reliable during use. Specifically, the elastic positioning bead structure can adopt the existing spring-abutting positioning bead structure.

[0071] In this embodiment, the elastic fork mechanism 61 can adopt an existing fork mechanism, so it is not described in detail.

[0072] In this embodiment, the drumstick driving mechanism 630 can be implemented by a gear set structure pulled by a wire or a gear set structure driven by a motor. It can be implemented by using existing mechanisms, so it is not described in detail.

[0073] In this embodiment, the transmission capable of shifting up and down under heavy load is further provided with an anti-neutral mechanism, which includes at least one ratchet member 05 mounted in the first gear layshaft gear 04 on the layshaft 2 and a reset member 06 for resetting the ratchet member 05;

[0074] The pawl member 05 is located in the first-gear countershaft gear 04; when in use, when the countershaft 2 drives the pawl member 05 to rotate, the pawl member 05 slips in the first-gear countershaft gear 04; when the main shaft 1 drives the first-gear mainshaft gear 07 and the first-gear countershaft gear 04 to rotate, the pawl member 05 engages with the first-gear countershaft gear 04, so that the pawl member 05 drives the countershaft 2 to rotate.

[0075] In actual application, when the gearbox is in normal use, when the countershaft 2 drives the pawl member 05 to rotate, the pawl member 05 slips in the first gear countershaft gear 04, and the pawl member 05 cannot engage and drive the first gear countershaft gear 04, which does not affect the transmission of other high gear gears; when the gear shift cable of the gearbox breaks, or the drumstick mechanism or slider mechanism in the gear shift control system is deformed, stuck, etc., so that the gearbox cannot be shifted, the main shaft 1 drives the first gear mainshaft gear 07 to rotate, and the first gear mainshaft gear 07 drives the first gear countershaft gear 04 to rotate, and the first gear countershaft gear 04 engages with the pawl member 05 and drives the countershaft 2 to rotate, thereby preventing the gearbox from being in neutral.

[0076] This anti-neutral mechanism ensures that the transmission is always in neutral, thus avoiding the danger of riding a bicycle in neutral, ensuring riding safety and ensuring the safety and reliability of the product. Furthermore, the pawl member 05 and reset member 06 are mounted directly on the countershaft 2 within the first gear countershaft gear 04, effectively utilizing the installation space between the first gear countershaft gear 04 and the countershaft 2, making the structure more compact, helping to reduce the overall size of the transmission and lighten the weight of the transmission and bicycle, thus possessing high practicality.

[0077] In this embodiment, the secondary shaft 2 is provided with a pawl groove 21 , and the pawl member 05 is provided with a mounting portion 051 that cooperates with the pawl groove 21 . The mounting portion 051 is mounted in the pawl groove 21 to facilitate the installation of the pawl member 05 .

[0078] The pawl member 05 is also provided with a pawl portion 052, one side of the pawl portion 052 is provided with an arcuate sliding surface 0521, and the other side of the pawl portion 052 is provided with an engaging surface 0522. Specifically, the structure of the pawl portion 052 and the mounting portion 051 is arranged so that the pawl member 05 is wedge-shaped as a whole; the arcuate sliding surface 0521 facilitates the pawl member 05 to slide out of the tooth groove of the first-gear countershaft gear 04, causing it to slip without engaging, and the engaging surface 0522 enables the pawl portion 052 to engage with the tooth groove of the first-gear countershaft gear 04, thereby driving the first-gear countershaft gear 04 and the countershaft 2 to rotate, so that the gearbox is not in a neutral state.

[0079] In actual use, the first-gear mainshaft gear 07 and the first-gear countershaft gear 04 are both set to the first gear of the transmission. When other gears, such as the second to fifth gears, can be shifted and changed normally, the rotation speed of the pawl member 05 driven by the countershaft 2 is higher than the rotation speed of the first-gear countershaft gear 04, causing the arc-shaped sliding surface 0521 of the pawl member 05 to contact the tooth groove of the first-gear countershaft gear 04, thereby slipping and idling without engaging, and does not affect the use of other gears.

[0080] In this embodiment, the pawl member 05 is provided with a first fixing groove 053, and the countershaft 2 is provided with a second fixing groove 22. The reset member 06 is an annular spring. The reset member 06 engages with the first fixing groove 053 and the second fixing groove 22 to mount the pawl member 05 on the countershaft 2. The reset member 06 holds the pawl member 05 in place, constantly tilting the pawl portion 052 of the pawl member 05 out of the pawl groove 21. When the pawl member 05 comes into contact with the first gear countershaft gear 04 and slips, the pawl member 05 is pressed downward by the first gear countershaft gear 04 and slides past it. The elasticity of the reset member 06 again tilts the pawl portion 052 out of the pawl groove 021.

[0081] The matching structure of the countershaft 2, the first-gear countershaft gear 04, the reset member 06 and the ratchet member 05 of this gearbox is easy to install and replace, and the structural design is ingenious. It reduces at least one set of gear-shift ratchet mechanisms for separating and engaging the gears of the gears, reduces the space occupied by the internal space of the gearbox, and makes the gearbox smaller, lighter and safer.

[0082] Example 2.

[0083] refer to Figures 14 to 16 As shown, the difference between the second embodiment and the first embodiment is that the flexible reverse gear shift drum 633 includes a reverse gear shift drum rod 01, a second shift sleeve 02 and a second torsion spring 03 installed on the reverse gear shift drum rod 01,

[0084] One end of the second torsion spring 03 abuts against the reverse gear shift drum rod 01, and the other end of the second torsion spring 03 abuts against the second gear shift sleeve 02; the second gear shift sleeve 02 is provided with a second reverse gear shift groove 04; the reverse gear member 62 is provided with a reverse gear guide pin, and the reverse gear guide pin is provided in the second reverse gear shift groove 04.

[0085] In this embodiment, the flexible reverse gear shift drum 633 uses an independent reverse gear shift drum stick 01 to control and drive the reverse gear member 62. When shifting gears, the drum stick driving mechanism 630 controls the rotation of the shift fork drum stick 6321 and the reverse gear shift drum stick 01 to respectively drive the elastic shift fork mechanism 61 and the reverse gear member 62 to move synchronously. When the reverse gear member 62 contacts the top of the reverse gear protrusion 51, the shift fork drum stick 6321 and the reverse gear shift drum stick 01 move independently and will not affect the shift fork drum stick 6321 driving the elastic shift fork mechanism 61 to move, thereby preventing the shift fork shift drum 632 from getting stuck and not affecting the gear shifting action of the transmission.

[0086] In this embodiment, the reverse gear shift drum rod 01 is axially provided with a third abutment 011, and the second gear shift sleeve 02 is axially provided with a fourth abutment 021. One end of the second torsion spring 03 abuts against the third abutment 011, and the other end of the second torsion spring 03 abuts against the fourth abutment 021. When shifting from low gear to M gear, the third abutment 011 abuts against the fourth abutment 021, so that the reverse gear shift drum rod 01 pushes the second gear shift sleeve 02 to rotate. When the gearbox shifts from M gear to low gear, the third abutment 011 squeezes the second torsion spring 03, and the second torsion spring 03 squeezes the fourth abutment 021, so that the reverse gear shift drum rod 01 pushes the second gear shift sleeve 02 to rotate through the second torsion spring 03. The structural design of this flexible reverse gear shift drum 633 is ingenious. It is designed independently from the shift fork drum rod 6321. When shifting up or down, the flexible reverse gear shift drum 633 and the shift fork drum rod 6321 cooperate with each other.

[0087] In this embodiment, the drumstick driving mechanism 630 can be provided with a single mechanism to simultaneously drive the flexible reverse gear shift drum 633 and the shift fork shift drum 632 to rotate, or it can be provided with two mechanisms to respectively drive the flexible reverse gear shift drum 633 and the shift fork shift drum 632 to rotate. The drumstick driving mechanism 630 can be implemented using an existing mechanism, so it will not be described in detail.

[0088] Example 3.

[0089] The present invention further provides a bicycle comprising the transmission case of the first or second embodiment that can shift up and down under heavy load.

[0090] In this example, when the transmission of the bicycle changes from the M gear to the low gear, with the help of the continued rotation of the main shaft 1 or the secondary shaft 2 under the load, the retracting member 62 is used to contact the retracting protrusion 51 of the ratchet 5 to make the ratchet 5 withdraw from the M gear main shaft gear 3 or the M gear secondary shaft gear 4, and then the elastic fork mechanism 61 is used to pull the ratchet 5 back to the preset position, thereby realizing the transmission downshifting from high gear to low gear without unloading the load. For example, the bicycle can downshift without stopping to pedal, and the circumferential driving force of the shaft rotation under load is effectively utilized to downshift. Compared with the existing transmission that requires stopping to downshift, and there are problems such as cable breakage or pawl deformation and jamming, the transmission of this bicycle can shift up and down smoothly when loaded, avoiding the force unloading method of stopping to downshift when climbing, which affects the forward balance of the bicycle and causes the risk of falling, thereby greatly improving the riding safety and riding experience. At the same time, it reduces the risk of wear and damage to the transmission, extends the service life, and reduces the failure rate and cost of use.

[0091] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are all within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A gearbox capable of shifting up and down under heavy loads, comprising a gearbox and a gearshift control system (6); a main shaft (1) and a countershaft (2) mounted in parallel in the gearbox; an M-position mainshaft gear (3) mounted on the mainshaft (1); an M-position countershaft gear (4) meshing with the M-position mainshaft gear (3) mounted on the countershaft (2); a ratchet (5) meshing with the M-position mainshaft gear (3) or the M-position countershaft gear (4) mounted on the mainshaft (1) or the countershaft (2); and characterized in that: The ratchet (5) is provided with an axially protruding backshift protrusion (51); the shift control system (6) comprises an elastic fork mechanism (61), a backshift member (62), and a shift drive mechanism (63) for driving the elastic fork mechanism (61) and the backshift member (62) to move; the ratchet (5) is drivingly connected to the elastic fork mechanism (61); The gear shift driving mechanism (63) comprises a gear shift drum stick mechanism (631) and a drum stick driving mechanism (630) for driving the gear shift drum stick mechanism (631) to rotate; The shift drum rod mechanism (631) comprises a shift fork shift drum (632) and a flexible reverse shift drum (633); the elastic shift fork mechanism (61) is drivingly connected to the shift fork shift drum (632), and the reverse shift member (62) is drivingly connected to the flexible reverse shift drum (633); When shifting from a low gear to an M gear, the drumstick driving mechanism (630) drives the shift fork shift drum (632) and the flexible backshift shift drum (633) to rotate, and the shift fork shift drum (632) and the flexible backshift shift drum (633) respectively drive the elastic shift fork mechanism (61) and the backshift member (62) to move from a preset position toward the M gear main shaft gear (3) or the M gear countershaft gear (4), so that the elastic shift fork mechanism (61) drives the ratchet (5) to engage with the M gear main shaft gear (3) or the M gear countershaft gear (4), thereby realizing the transmission upshift; When shifting from the M gear to the low gear, the drumstick driving mechanism (630) drives the shift fork shift drum (632) and the flexible backshift shift drum (633) to rotate, so that the shift fork shift drum (632) and the flexible backshift shift drum (633) respectively drive the elastic shift fork mechanism (61) and the backshift member (62) to move away from the M gear main shaft gear (3) or the M gear countershaft gear (4) to a preset position. When the main shaft (1) or the countershaft (2) continues to rotate, when the backshift member (62) contacts one side of the backshift protrusion (51) of the ratchet (5), the backshift member (62) contacts the backshift protrusion (51). 1) so that the ratchet (5) exits the M-position main shaft gear (3) or the M-position countershaft gear (4), the elastic shift fork mechanism (61) pulls the ratchet (5) back to a preset position, and the gearbox downshifts; when the backshift member (62) contacts the top of the backshift protrusion (51), the shift fork shift drum (632) continues to rotate to drive the elastic shift fork mechanism (61) to move, and after the backshift member (62) and the backshift protrusion (51) disappear, the backshift member (62) is driven by the flexible backshift shift drum (633) to move back to a synchronous state with the elastic shift fork mechanism (61) and move to a preset position.

2. A transmission capable of shifting up and down under heavy loads according to claim 1, characterized in that: The shift fork shift drum (632) comprises a shift fork drum rod (6321) and a shift fork shift groove (6322) arranged on the shift fork drum rod (6321); the elastic shift fork mechanism (61) is provided with a shift fork shift guide pin (611), and the shift fork shift pin (611) is arranged in the shift fork shift groove (6322).

3. According to claim 2, a transmission capable of shifting up and down gears under heavy load, the flexible reverse gear shift drum (633) comprises a first gear shift sleeve (6331) and a first torsion spring (6332), the first gear shift sleeve (6331) being mounted on the shift fork drum rod (6321); the first torsion spring (6332) being sleeved on the shift fork drum rod (6321), one end of the first torsion spring (6332) being in contact with the shift fork drum rod (6321), and the other end of the first torsion spring (6332) being in contact with the first gear shift sleeve (6331); The first shift sleeve (6331) is provided with a first shift-return groove (6333), the shift-return member (62) is provided with a shift-return guide pin (621), and the shift-return guide pin (621) is provided in the first shift-return groove (6333).

4. According to the transmission capable of shifting up and down under heavy loads as described in claim 3, a first abutment platform (6323) is provided axially on the shift fork drum rod (6321), a second abutment platform (6334) is provided axially on the first shift sleeve (6331), one end of the first torsion spring (6332) abuts against the first abutment platform (6323), and the other end of the first torsion spring (6332) abuts against the second abutment platform (6334); When shifting from the low gear to the M gear, the first abutment platform (6323) abuts against the second abutment platform (6334), so that the shift fork drum stick (6321) pushes the first shift sleeve (6331) to rotate together; When shifting from the M gear to the low gear, the first abutment platform (6323) squeezes the first torsion spring (6332), and the first torsion spring (6332) squeezes the second abutment platform (6334), so that the shift fork drum stick (6321) pushes the first shift sleeve (6331) to rotate through the first torsion spring (6332).

5. The transmission capable of shifting up and down under heavy load according to claim 2, characterized in that: The flexible reverse gear shift drum (633) comprises a reverse gear shift drum rod (01), a second gear shift sleeve (02) mounted on the reverse gear shift drum rod (01), and a second torsion spring (03). One end of the second torsion spring (03) abuts against the reverse gear shift drum rod (01), and the other end of the second torsion spring (03) abuts against the second gear shift sleeve (02); The second shift sleeve (02) is provided with a second shift-return groove (04); the shift-return member (62) is provided with a shift-return guide pin, and the shift-return guide pin is provided in the second shift-return groove (04).

6. According to the transmission capable of shifting up and down under heavy loads as described in claim 5, a third abutment (011) is provided axially on the reverse gear shift drum rod (01), a fourth abutment (021) is provided axially on the second gear shift sleeve (02), one end of the second torsion spring (03) abuts against the third abutment (011), and the other end of the second torsion spring (03) abuts against the fourth abutment (021); When shifting from the low gear to the M gear, the third abutment platform (011) abuts against the fourth abutment platform (021), so that the reverse gear shift drum stick (01) pushes the second gear shift sleeve (02) to rotate; when shifting from the M gear to the low gear, the third abutment platform (011) presses the second torsion spring (03), and the second torsion spring (03) presses the fourth abutment platform (021), so that the reverse gear shift drum stick (01) pushes the second gear shift sleeve (02) to rotate through the second torsion spring (03).

7. The transmission capable of shifting up and down under heavy load according to claim 1, characterized in that: There are two retraction protrusions (51), which are arranged on both sides of the ratchet (5), and the retraction member (62) is located between the two retraction protrusions (51); The shift control system (6) is provided with a shift guide rod (64), and the elastic shift fork mechanism (61) and / or the backstop (62) are slidably mounted on the shift guide rod (64); The ratchet (5) is provided with a neutral positioning hole (52), and the main shaft (1) is provided with an elastic positioning bead structure. When the ratchet (5) is in neutral, the positioning beads of the elastic positioning bead structure are snapped into the neutral positioning hole (52).

8. The transmission capable of shifting up and down under heavy load according to claim 1, characterized in that: The transmission capable of shifting up and down under heavy load is also provided with an anti-neutral gear mechanism, the anti-neutral gear mechanism comprising at least one ratchet member (05) installed in a first gear countershaft gear (04) on the countershaft (2) and a reset member (06) for resetting the ratchet member (05); The ratchet member (05) is located in the first gear countershaft gear (04); when in use, when the countershaft (2) drives the ratchet member (05) to rotate, the ratchet member (05) slips in the first gear countershaft gear (04); when the main shaft (1) drives the first gear mainshaft gear (07) and the first gear countershaft gear (04) to rotate, the ratchet member (05) engages with the first gear countershaft gear (04), so that the ratchet member (05) drives the countershaft (2) to rotate.

9. A transmission capable of shifting up and down under heavy loads according to claim 8, characterized in that: The secondary shaft (2) is provided with a pawl groove (21), the pawl member (05) is provided with a mounting portion (051) that cooperates with the pawl groove (21), and the mounting portion (051) is mounted in the pawl groove (21); The pawl member (05) is further provided with a pawl portion (052), one side of the pawl portion (052) is provided with an arc-shaped sliding surface (0521), and the other side of the pawl portion (052) is provided with an engaging surface (0522); The pawl member (05) is provided with a first fixing groove (053), the secondary shaft (2) is provided with a second fixing groove (22), the reset member (06) is an annular spring, and the reset member (06) is embedded in the first fixing groove (053) and the second fixing groove (22) to install the pawl member (05) on the secondary shaft (2); the reset member (06) always makes the pawl portion (052) of the pawl member (05) tilt up and extend out of the pawl groove (21).

10. A bicycle, characterized in that: A gearbox capable of shifting up and down under heavy loads as described in any one of claims 1 to 9.

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