CN115929867A - Compact bicycle center shaft gearbox with load speed change function and gear shifting method thereof - Google Patents

Abstract

The invention relates to a bicycle speed changer in a vehicle, in particular to a compact bicycle middle shaft gearbox with load speed change and a gear shifting method thereof, wherein the compact bicycle middle shaft gearbox comprises a box type speed changer and a gear shifting device, one of main shaft gears is a direct drive gear, and an output chain wheel is fixed on the direct drive gear; at least one of the driving ratchet wheel and the driven ratchet wheel is a double-ratchet wheel, two main shaft gears or two auxiliary shaft gears with single ratchets are arranged on two sides of the double-ratchet wheel, the double-ratchet wheel moves left and right on the main shaft or the auxiliary shaft and is meshed with or separated from the two main shaft gears or the two auxiliary shaft gears of the single ratchets respectively through the ratchets on the two sides; the gear shifting deflector rod and the shifting fork are elastic connecting pieces, and the compact bicycle speed changer adopting the technical scheme has a compact structure, can directly shift forward and backward, and is stable in operation.

Description

Compact bicycle center shaft gearbox with load speed change function and gear shifting method thereof

Technical Field

The invention relates to a bicycle speed changer in a vehicle, in particular to a compact bicycle bottom bracket bearing speed changing box with load speed changing and a gear shifting method thereof.

Background

A bicycle is also called a bicycle or a bicycle. At present, the transmission speed ratio of a bicycle is fixed and the speed ratio is adjustable, most of bicycle speed ratio-adjustable bicycles adopt a plurality of flywheel fluted discs with different tooth numbers fixedly arranged on a flywheel, and a chain adjusting sprocket wheel is combined with the flywheel fluted discs with different tooth numbers to realize different transmission speed ratios.

The existing speed-changing bicycle speed changer generally adopts a structure with a plurality of chain discs, and the chain is matched and connected with different chain discs by adjusting the position of the chain, so that the mode is relatively troublesome in gear shifting, and the gear shifting is required to be carried out when the bicycle runs, so that the gear shifting failure often occurs, and the abrasion to the chain is large; there are also individual speed-changing bicycle speed-changing devices using a gear box, for example, chinese patent CN205168799U discloses a speed-changing device in a center shaft type bicycle, which is characterized in that a first groove is provided between two second transmission gears of each planetary gear set, and a first protrusion capable of being embedded into the first groove is provided on an inner circumferential surface of a ring gear, so that six ring gears can be fixed on a planetary gear fixing frame. The existing speed changer is mostly driven by common gears and also driven by planet gears, and the speed changer is generally provided with a plurality of meshes. Because the structure of derailleur is more complicated, the part is many, needs the precision fit between each part for the volume of derailleur also is difficult to dwindle. Meanwhile, when the transmission shifts gears, the transmission needs to enter a neutral gear first and then shift gears, and the operation is complex. In addition, certain potential safety hazards exist in neutral gear, and partial safety accidents occur due to the fact that the vehicle enters the neutral gear.

Meshing is an important component of a transmission, and the existing meshing structure is complex: a ring is arranged beside each transmission gear of each gear, a conical surface for friction is arranged on each gear, a meshing sleeve is arranged between the two rings, and structures such as a sliding block, a spring ring and the like need to be arranged between the meshing sleeve and the rings. When the gear is shifted, the neutral gear is firstly shifted, and then the gear is shifted; when the gear is shifted, the ring and the transmission gear can be meshed with the meshing sleeve under the action of friction force, and then gear shifting is completed. CN203098620U discloses an automobile transmission device, which comprises a gear hub, a ring, a meshing sleeve, and a sliding block for driving the meshing sleeve to push the ring to slide when shifting gears, wherein the ring is provided with a groove matched with the sliding block, the sliding block is located in the groove when in neutral, an elastic body is attached to the side surface of the sliding block, and the end surface of the elastic body is in contact with the groove surface of the groove. The utility model discloses a motor transmission ware that provides makes slider and ring be non-rigid contact when shifting, can reduce the noise of shifting, can avoid ring and keep off the continuous friction of gear wheel when picking simultaneously.

The current compact bicycle speed changer has the defects of non-compact gear shifting structure and incapability of realizing better direct gear shifting and gear backing.

Disclosure of Invention

The invention aims to provide a compact bicycle bottom bracket bearing gearbox with load speed change, which has compact structure, can directly shift into and shift out, has stable operation and overcomes the defects of the prior compact bicycle speed changer that the gear shifting structure is not compact and the gear shifting can not be better shifted and shifted.

In order to achieve the purpose, the compact bicycle center shaft gearbox with load speed change comprises a box type speed change device and a gear shift device, wherein the box type speed change device comprises a box body, a main shaft, an auxiliary shaft and an output chain wheel, a plurality of main shaft gears and driving ratchet wheels are arranged on the main shaft, a plurality of auxiliary shaft gears and driven ratchet wheels are arranged on the auxiliary shaft, a shifting groove is formed in the middle of each driving ratchet wheel and each driven ratchet wheel, and the main shaft gears and the auxiliary shaft gears are mutually matched and meshed; the gear shifting device comprises a gear shifting drum wheel, a gear shifting driving lever and a gear shifting fork, the gear shifting drum wheel is rotationally fixed on a box body, two ends of a main shaft and two ends of an auxiliary shaft are arranged on the box body through bearings, the gear shifting driving lever can be movably fixed on the box body in a left-right moving mode, a gear shifting drum wheel groove is formed in the circumferential surface of the gear shifting drum wheel, the gear shifting fork comprises a lower shifting fork part and an upper shifting fork connecting part, the shifting fork part is clamped in a shifting groove in the middle of the ratchet wheel, the front end of the gear shifting driving lever is movably fixed in the gear shifting drum groove, the rear end of the gear shifting driving lever is movably connected with the shifting fork connecting part, one of the main shaft gears is a direct-drive gear, and the output chain wheel is fixed on the direct-drive gear; at least one of the driving ratchet wheel and the driven ratchet wheel is a double-ratchet wheel, two main shaft gears or two auxiliary shaft gears with single ratchet are arranged on two sides of the double-ratchet wheel, the double-ratchet wheel moves left and right on the main shaft or the auxiliary shaft and is respectively meshed with or separated from the two main shaft gears or the two auxiliary shaft gears of the single ratchet through the ratchets on the two sides; and the shifting deflector rod and the shifting fork are elastic connecting pieces.

By adopting the technical scheme, because one of the main shaft gears is a direct drive gear, the output chain wheel is fixed on the direct drive gear, the compact transmission relatively existing reduces the gear pair, so that the gear shifting structure is more compact, and meanwhile, the gear shifting deflector rod and the connecting piece of the shifting fork are elastic connecting pieces, so that when the gear is shifted or shifted, rigid contact between ratchets is avoided when the ratchets corresponding to the ratchets of the main shaft gear or the auxiliary shaft gear are combined, the gear beating and clamping stagnation phenomena can not occur, the direct shift can be better, and the mature shift drum technology can also ensure the defect that the existing compact transmission is easy to shift automatically under the condition of poor riding road conditions.

Furthermore, the limiting elastic connecting piece adopts a simple and practical metal elastic piece, the upper end of the metal elastic piece is fixedly connected to the gear shifting lever, and the lower end of the metal elastic piece movably clamps the gear shifting fork.

In the same way, the elastic connecting piece is limited to be a torsion spring, the torsion spring comprises a torsion spring body and a torsion spring output end, the torsion spring body is fixedly connected to the gear shifting lever, and the gear shifting lever is movably clamped by the torsion spring output end.

Furthermore, other specific structures except for the shift drum wheel in the gear shifting device are specifically limited, namely the gear shifting device further comprises a fixing plate and a shifting fork guide rod, the fixing plate is fixed on the box body, the shifting fork guide rod is fixed on the fixing plate or directly fixed on the box body, the shifting fork connecting part is a hollow tube, and the hollow tube is movably sleeved on the shifting fork guide rod.

Still further, a five-gear transmission adopting the technical scheme is limited, wherein a first-gear main shaft gear, a fifth-gear main shaft gear, a third-gear main shaft gear, a fourth-gear main shaft gear and a direct-drive gear are arranged on the main shaft from left to right, a first double-ratchet wheel is arranged between the fifth-gear main shaft gear and the third-gear main shaft gear, and second double-ratchet wheels are arranged between the fourth-gear main shaft gear and the direct-drive gear, wherein the first-gear main shaft gear is fixedly connected to the main shaft, the fifth-gear main shaft gear, the third-gear main shaft gear, the fourth-gear main shaft gear and the direct-drive gear are freely sleeved on the main shaft, and the first double-ratchet wheel and the second double-ratchet wheel are slidably sleeved on the main shaft; the first-gear counter shaft gear, the fifth-gear counter shaft gear, the third-gear counter shaft gear, the fourth-gear counter shaft gear and the reverse gear are arranged on the counter shaft from left to right, a single ratchet wheel is arranged between the first-gear counter shaft gear and the fifth-gear counter shaft gear, the first-gear counter shaft gear is sleeved on the single ratchet wheel in an empty mode, and the fifth-gear counter shaft gear, the third-gear counter shaft gear, the fourth-gear counter shaft gear and the reverse gear are all fixedly connected to the counter shaft.

The five-gear gearbox structure is characterized in that the number of the shift deflector rods and the number of the shift forks are three, wherein the first shift deflector rod controls the first double-ratchet wheel, the second shift deflector rod controls the second double-ratchet wheel, and the third shift deflector rod controls the single-ratchet wheel.

The ratchet teeth are limited to be helical teeth, and under the thrust of the tooth roots of the helical teeth, due to the angle of the ratchet teeth, when the working surface of the ratchet teeth is stressed, the direction of the force faces the root of the ratchet teeth, so that the gear ratchet and the sleeve ratchet are automatically clamped, and the torque is transmitted;

according to the invention, the technical effect that the gear and the ratchet wheel are connected in a matched manner in the way is as follows: (1) When clamping is needed, the ratchet wheel ratchet and the gear ratchet are easy to engage and can be prevented from falling off; (2) When the speed difference exists, the ratchet wheel ratchet and the gear ratchet are easy to disengage. The specific reasons are: due to the ratchet angle, when the working surface of the ratchet is stressed, the direction of the force faces to the root of the ratchet, so that the ratchet of the ratchet wheel and the ratchet of the gear are automatically clamped, and the torque is transmitted. Because the back of the tooth angle of the ratchet is gentle, the moment can not be transferred, and when the back of the tooth of the ratchet is stressed, the direction of the force is far away from the tooth root, so that the ratchet of the ratchet wheel and the ratchet of the gear are far away from each other, and the ratchet of the gear is automatically separated.

Another object of the present invention is to provide a specific shifting method for a five-speed compact bicycle transmission, comprising 1) when the initial position is first speed, the shift drum controls a third shift lever to drive a single ratchet wheel to move left, and the ratchet on the left of the single ratchet wheel is engaged with the ratchet on the right of a first-speed countershaft gear; other ratchet wheels are in a separation state, the main shaft drives a first-gear main shaft gear to rotate, the first-gear main shaft gear drives a first-gear auxiliary shaft gear, an auxiliary shaft and a reverse gear to rotate, the reverse gear drives a direct-drive gear sleeved on the main shaft to rotate, and an output chain wheel rotates;

2) When the gear is shifted from the first gear to the second gear, the gear shifting drum wheel is rotated, the third gear shifting rod drives the single ratchet wheel to move rightwards, and the ratchet on the left side of the single ratchet wheel is separated from the ratchet on the right side of the first gear counter shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move on the right, and the ratchet on the right of the second double-ratchet wheel is meshed with the ratchet on the left of the direct drive gear; the power directly rotates through an output chain wheel fixed on the direct drive gear, and the first double-ratchet wheel and the single-ratchet wheel are both in a ratchet separation state;

3) When the gear is shifted from the second gear to the third gear, the gear shifting drum wheel is rotated, the third gear shifting driving lever does not move in a displacement mode, the second gear shifting driving lever drives the second double-ratchet wheel to move leftwards, and the ratchet on the right side of the second double-ratchet wheel is separated from the ratchet on the left side of the direct drive gear; meanwhile, the first gear shifting driving lever drives the first double-ratchet wheel to move rightwards, the ratchet on the right side of the first double-ratchet wheel is meshed with the ratchet on the left side of the three-gear main shaft gear, the three-gear main shaft gear drives the three-gear auxiliary shaft gear to rotate, the three-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear sleeved on the main shaft to rotate, and the output chain wheel rotates;

4) When the gear is shifted from the third gear to the fourth gear, the gear shifting drum wheel is rotated, the first gear shifting deflector rod drives the first double-ratchet wheel to move leftwards, and the ratchet on the right of the first double-ratchet wheel is separated from the ratchet on the left of the third-gear main shaft gear; meanwhile, the second gear shifting deflector rod drives the second double-ratchet wheel to move leftwards, the ratchet positioned on the left side of the second double-ratchet wheel is meshed with the ratchet positioned on the right side of the four-gear main shaft gear, the four-gear main shaft gear drives the four-gear auxiliary shaft gear to rotate, the four-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct drive gear sleeved on the main shaft to rotate, and the output chain wheel rotates;

5) When the gear is shifted from the fourth gear to the fifth gear, the gear shifting drum wheel is rotated, the second gear shifting deflector rod drives the second double-ratchet wheel to move rightwards, and the ratchet on the left side of the second double-ratchet wheel is separated from the ratchet on the right side of the fourth-gear main shaft gear; meanwhile, the first gear shifting deflector rod drives the first double-ratchet wheel to move leftwards, and the ratchet on the left side of the first double-ratchet wheel is meshed with the ratchet on the right side of the fifth-gear main shaft gear; the five-gear main shaft gear drives the five-gear auxiliary shaft gear to rotate, the five-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear which is sleeved on the main shaft in a hollow mode to rotate, and the output chain wheel rotates;

6) When the gear is shifted down from the fifth gear to the fourth gear, the gear shifting drum wheel is rotated reversely, the first gear shifting deflector rod drives the first double-ratchet wheel to move rightwards, and the ratchet on the left of the first double-ratchet wheel is separated from the ratchet on the right of the fifth-gear main shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move leftwards, and the ratchet on the left side of the second double-ratchet wheel is meshed with the ratchet on the right side of the fourth-gear main shaft gear; the four-gear main shaft gear drives the four-gear auxiliary shaft gear to rotate, the four-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear which is sleeved on the main shaft in a hollow mode to rotate, and the output chain wheel rotates;

7) When the gear is shifted down from the fourth gear to the third gear, the gear shifting drum wheel is rotated reversely, the second gear shifting deflector rod drives the second double-ratchet wheel to move rightwards, and the ratchet on the left of the second double-ratchet wheel is separated from the ratchet on the right of the fourth-gear main shaft gear; meanwhile, the first gear shifting driving lever drives the first double-ratchet wheel to move rightwards, and the ratchet on the right side of the first double-ratchet wheel is meshed with the ratchet on the left side of the third-gear main shaft gear; the three-gear main shaft gear drives the three-gear auxiliary shaft gear to rotate, the three-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear sleeved on the main shaft to rotate, and the output chain wheel rotates;

8) When the gear is shifted from the third gear to the second gear, the gear shifting drum wheel is rotated reversely, the first gear shifting driving lever drives the first double-ratchet wheel to move leftwards, and the ratchet on the right side of the first double-ratchet wheel is separated from the ratchet on the left side of the third-gear main shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move rightwards, and the ratchet on the right side of the second double-ratchet wheel is meshed with the ratchet on the left side of the direct drive gear; the direct drive gear directly rotates through an output chain wheel fixed on the direct drive gear.

9) When the gear is shifted down from the second gear to the first gear, the gear shifting drum wheel is rotated reversely, the second gear shifting deflector rod drives the second double-ratchet wheel to move leftwards, and the ratchet on the right side of the second double-ratchet wheel is separated from the ratchet on the left side of the direct drive gear; meanwhile, the third shift deflector rod drives the single ratchet wheel to move leftwards, the ratchet positioned on the left side of the single ratchet wheel is meshed with the ratchet on the right side of the first-gear counter shaft gear; the first-gear main shaft gear drives the first-gear auxiliary shaft gear to rotate, the first-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear sleeved on the main shaft to rotate, and the output chain wheel rotates;

10 In different initial states, the ratchet engagement position corresponds to the specific state described above.

The gear shifting method adopting the technical scheme is simple to operate, the gear shifting operation is firstly carried out in the gear shifting process, and the first gear engagement is automatically disengaged after the second gear shifting is finished. The gear shifting mode can shift under the condition of load, and the gear shifting at any time is realized. Meanwhile, the gear shifting process is simple to operate, and the safety during gear shifting is greatly improved. And the process time of the gear shifting is short, and the gear shifting is realized by shifting the gear shifting drum.

When the gear is shifted, the gear of the gear drives the ratchet wheel of the gear to rotate, and when the gear is shifted, the force bearing surface of the ratchet wheel is changed into a tooth back due to the high rotating speed of the ratchet wheel of the gear, the direction of the force generated by the tooth back is far away from the tooth root, and the gear of the gear can be pushed to the direction far away from the ratchet wheel of the first gear.

The tooth profile of the ratchet teeth mentioned in the present invention is the same as the "ratchet teeth" in the so-called "ratchet teeth", that is: the angles of the two flanks are different, so that only one of them can transmit torque. The orientation of the ratchet arrangement of the present invention differs from conventional approaches: the ratchet teeth are annular, but the direction of the tooth tips is towards the side, and the specific angle is based on the torque which can be transmitted between the sleeve and the gear.

Compared with the prior art, the technical scheme has the advantages that firstly, the shifting fork is driven by the elastic sheet or the torsion spring on the shifting lever, so that the gear hitting or the clamping caused by the hard contact of the ratchet is avoided; and secondly, the foot falling habit of the bicycle rider is facilitated. Because the elastic sheet or the torsional spring on the shifting lever drives the shifting fork to control the ratchet wheel to be meshed with the lateral ratchet of the gear, when the reversing pin reverses the main shaft, the tooth backs between the ratchet wheel and the lateral ratchet of the gear have mutual thrust, and the elastic sheet or the torsional spring can enable the ratchet wheel controlled by the shifting fork to be separated from the gear in the axial direction through deformation; thirdly, the gear shifting device has a static gear shifting function, and even if the gear shifting device does not rotate, due to the deformation function of the elastic sheet or the torsion spring on the shifting lever, the gear can be switched to other gears at any gear; and fourthly, gear shifting is carried out under load, and when the gear is shifted up, the high gear is automatically separated from the low gear after entering the gear according to the speed difference principle. During gear reduction, gear reduction can be performed in advance and step by step, even when the high gear runs, the shift lever can be shifted to the low gear, at the moment, the elastic piece and the torsion spring on the low gear shift lever deform, the ratchet wheel and the lateral ratchet of the gear at the low gear are in a half-clutch state, when stepping is stopped and started, the load is 0, the inertia of the gear at the high gear is disengaged and separated from the ratchet wheel, and when stepping is performed again, the ratchet wheel at the low gear and the lateral ratchet of the gear are immediately combined to transmit torque.

Drawings

FIG. 1 is a schematic view of the construction of a spindle;

FIG. 2 is a schematic view of a lay shaft;

FIG. 3 is an assembled view of the main shaft with the main shaft gear assembled and the countershaft with the shift drum assembled;

FIG. 4 is an assembled schematic view of the main shaft assembled with the output sprocket and the auxiliary shaft assembled with the main shaft gear;

FIG. 5 is a rear view of the structure of FIG. 4;

FIG. 6 is a schematic structural view of a direct drive gear;

FIG. 7 is a schematic structural view of gears including a first-gear main shaft gear, a third-gear main shaft gear, a fourth-gear main shaft gear, a fifth-gear main shaft gear, and a first-gear counter shaft gear; a reverse gear; a third-gear counter shaft gear; a fourth-gear counter shaft gear; a fifth-gear counter shaft gear;

FIG. 8 is a schematic view of the ratchet wheel configuration; the ratchet wheel comprises a first double-ratchet wheel; a second double ratchet; a single ratchet wheel;

FIG. 9 is an enlarged view of the metal spring plate of the elastic connecting member;

fig. 10 is an enlarged schematic view showing a structure in which the elastic connection member is a torsion spring.

In the figure identification, 1 is a main shaft; 11 is a first-gear main shaft gear; 12 is a direct drive gear; 13 is a three-gear main shaft gear; 14 is a four-speed spindle gear; 15 is a five-speed main shaft gear; 18 is a first double ratchet; 19 is a second double ratchet;

2 is a secondary shaft; 21 is a first gear counter gear; 22 is a reverse gear; 23 is a three-speed counter gear; 24 is a four-speed counter gear; 25 is a five speed counter gear; 28 is a single ratchet;

3 is an output sprocket;

4 is a shift drum; 41 is a first shift lever; 42 is a second shift lever; 43 is a third shift lever; 44 is a shift drum groove; 45 is a shift fork; 453 is a metal dome; 454 is a compression spring; 455 is a fork guide bar; 456 is a torsion spring body; 457 is the torsion spring output end;

51 is an upper fixing plate; 52 is a lower fixing plate; 53 is a positioning plate;

Detailed Description

The technical solution of the present invention is further explained below with reference to the accompanying drawings and examples.

In a first embodiment, as shown in fig. 1 to 9, a compact bicycle middle shaft gearbox with load speed change comprises a box type speed change device and a gear shift device, wherein the box type speed change device comprises a box body, a main shaft 1, a counter shaft 2 and an output chain wheel 3, the gearbox is a five-gear gearbox, five driving gears of a first-gear main shaft gear 11, a fifth-gear main shaft gear 15, a third-gear main shaft gear 13, a fourth-gear main shaft gear 14 and a direct drive gear 12 are arranged on the main shaft from left to right, a first double ratchet 18 is arranged between the fifth-gear main shaft gear and the third-gear main shaft gear, a second double ratchet 19 is arranged between the fourth-gear main shaft gear 14 and the direct drive gear 12, wherein the first-gear main shaft gear is fixedly connected to or integrally formed with the main shaft, the fifth-gear main shaft gear 15, the third-gear main shaft gear 13, the fourth-gear main shaft gear 14 and the direct drive gear 12 are freely sleeved on the main shaft 1, and the first double ratchet 18 and the second double ratchet 19 are slidably sleeved on the main shaft 1; five countershaft gears including a first-gear countershaft gear 21, a fifth-gear countershaft gear 25, a third-gear countershaft gear 23, a fourth-gear countershaft gear 24 and a reverse gear 22 are arranged on the countershaft 2 from left to right, a single ratchet wheel 28 is arranged between the first-gear countershaft gear 21 and the fifth-gear countershaft gear 25, the first-gear countershaft gear 21 is sleeved on the countershaft 2 in an empty mode, the fifth-gear countershaft gear 25, the third-gear countershaft gear 23, the fourth-gear countershaft gear 24 and the reverse gear 22 are fixedly connected to the countershaft 2, and the main shaft gear and the countershaft gears are meshed in a matched mode; a shifting groove is arranged between the two driving ratchets, namely the first double-ratchet wheel 18 and the second double-ratchet wheel 19, and the driven ratchet wheel, namely the single-ratchet wheel 28; the ratchet teeth are all helical teeth.

The gear shifting device comprises a gear shifting drum wheel 4, a first gear shifting rod 41, a second gear shifting rod 42, a third gear shifting rod 43, three gear shifting rods and three gear shifting forks 45, an upper fixing plate 51, a lower fixing plate 52 and a shifting fork guide rod 455 which correspond to the gear shifting rods, wherein the gear shifting drum wheel is rotationally fixed on a box body, two ends of a main shaft and an auxiliary shaft are installed on the box body through bearings, the gear shifting rods can be movably fixed on the box body in a left-right mode, the rotating center line of the gear shifting drum wheel is parallel to the rotating center line of the auxiliary shaft, the upper fixing plate 51 and the lower fixing plate 52 are fixed on the box body under the condition that the rotation of gears is not prevented, the shifting fork guide rod 455 is fixed on the upper fixing plate 51 and the lower fixing plate 52, the shifting fork connecting portion 452 is a hollow pipe, and the hollow pipe is movably sleeved on the shifting fork guide rod 455. Two ends of the main shaft 1 and the auxiliary shaft 2 are arranged on the box body through bearings, and three shift deflector rods, namely a first shift deflector rod 41, a second shift deflector rod 42 and a third shift deflector rod 43, are movably fixed on the box body in a manner of moving left and right;

the gear shifting drum wheel groove 44 is arranged on the circumferential surface of the gear shifting drum wheel 4, the gear shifting fork comprises a lower-section shifting fork part 451 and an upper-section shifting fork connecting part 452, the shifting fork part 451 is clamped in the shifting groove in the middle of the ratchet wheel, the front ends of the three shifting shift levers of the first shifting lever 41, the second shifting lever 42 and the third shifting lever 43 are movably fixed in the gear shifting drum wheel groove 44, the rear ends of the three shifting lever of the first shifting lever 41, the second shifting lever 42 and the third shifting lever 43 are elastically movably connected at the shifting fork connecting part 452, namely, the connecting parts of the shifting lever and the shifting fork are elastic connecting parts, in the embodiment, the elastic connecting parts are metal elastic sheets 453, the upper end of the metal elastic sheet 453 is connected with the gear shifting lever 42, and the lower end of the metal elastic sheet 453 is connected with the gear shifting fork.

In the second embodiment, as shown in fig. 10, in the above technical solution, the elastic connecting member is a torsion spring, the torsion spring includes a torsion spring body 456 and a torsion spring output end 457, the torsion spring body 456 is fixedly connected to the shift lever 42, and the torsion spring output end 457 clamps the shift fork.

In addition, by adopting the technical scheme of the invention, the shift deflector rod and the shifting fork guide rod can be movably fixed on the box body in a left-right movement mode, the positions of the shift deflector rod and the shifting fork guide rod are not fixed by a fixing plate, and only the shift deflector rod and the shifting fork guide rod can be ensured to move only in a left-right direction but not in an up-down and front-back movement mode.

The invention relates to a gear shifting method of a compact bicycle center shaft gearbox with load speed change,

1) When the gearbox is in the neutral position, the first double-ratchet wheel, the second double-ratchet wheel and the single-ratchet wheel are all in a separated state with the corresponding gear;

2) When the gear is shifted from the neutral gear to the first gear, the gear shifting drum wheel 4 controls the third gear shifting rod 43 to drive the single-ratchet wheel 28 to move leftwards, and the ratchet on the left side of the single-ratchet wheel 28 is meshed with the ratchet on the right side of the first-gear counter shaft gear 21; other ratchet wheels are in a separated state, the main shaft 1 drives the first-gear main shaft gear 11 to rotate, the first-gear main shaft gear 11 drives the first-gear auxiliary shaft gear 21, the auxiliary shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct-drive gear which is sleeved on the main shaft 1 to rotate, and the output chain wheel 3 rotates;

3) When the gear is shifted from the first gear to the second gear, the gear shifting drum wheel 4 is rotated, the third gear shifting deflector rod 43 drives the single-ratchet wheel 28 to move rightwards, and the ratchet on the left side of the single-ratchet wheel 28 is separated from the ratchet 21 on the right side of the first-gear counter shaft gear; meanwhile, the second shift driving lever 42 drives the second double-ratchet wheel 19 to move towards the right, and the ratchet on the right of the second double-ratchet wheel 19 is meshed with the ratchet on the left of the direct drive gear 12; the power directly rotates through an output chain wheel fixed on the direct drive gear, and the first double-ratchet wheel and the single-ratchet wheel are both in a ratchet separation state;

4) When the gear is shifted from the second gear to the third gear, the gear shifting drum wheel 4 is rotated, the second gear shifting deflector rod 43 drives the second double-ratchet wheel 19 to move leftwards, and the ratchet on the right side of the second double-ratchet wheel 19 is separated from the ratchet on the left side of the direct drive gear 12; meanwhile, the first shift deflector rod 41 drives the first double-ratchet wheel 18 to move rightwards, the ratchet on the right of the first double-ratchet wheel 18 is meshed with the ratchet on the left of the third-gear main shaft gear 13, the third-gear main shaft gear 13 drives the third-gear counter shaft gear 23 to rotate, the third-gear counter shaft gear 23 drives the counter shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct drive gear 12 which is sleeved on the main shaft 1 to rotate, and the output chain wheel 3 rotates;

5) When the gear is shifted from the third gear to the fourth gear, the gear shifting drum wheel 4 is rotated, the first gear shifting poking rod 41 drives the first double-ratchet wheel 18 to move leftwards, and the ratchet on the right side of the first double-ratchet wheel 18 is separated from the ratchet on the left side of the third-gear main shaft gear 13; meanwhile, the second shift driving lever 42 drives the second double-ratchet wheel 19 to move leftwards, the ratchet on the left side of the second double-ratchet wheel 19 is meshed with the ratchet on the right side of the fourth-gear main shaft gear 14, the fourth-gear main shaft gear 14 drives the fourth-gear counter shaft gear 24 to rotate, the fourth-gear counter shaft gear 24 drives the counter shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct drive gear 12 which is sleeved on the main shaft to rotate, and the output chain wheel 3 rotates;

6) When the gear shifting drum 4 is rotated in a state of shifting from the fourth gear to the fifth gear, the second gear shifting rod 42 drives the second double-ratchet wheel 19 to move rightwards, and the ratchet on the left side of the second double-ratchet wheel 19 is separated from the ratchet on the right side of the fourth-gear main shaft gear 14; meanwhile, the first shift driving lever 41 drives the first double-ratchet wheel 18 to move leftward, and the ratchet on the left of the first double-ratchet wheel 18 is meshed with the ratchet on the right of the fifth-gear main shaft gear 15; the five-gear main shaft gear 15 drives the five-gear auxiliary shaft gear 25 to rotate, the five-gear auxiliary shaft gear 25 drives the auxiliary shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct-drive gear 12 which is sleeved on the main shaft 1 to rotate, and the output chain wheel 3 rotates;

7) When the gear is shifted down from the fifth gear to the fourth gear, the gear shifting drum 4 is rotated reversely, the first gear shifting rod 41 drives the first double-ratchet wheel 18 to move rightwards, and the ratchet on the left side of the first double-ratchet wheel 18 is separated from the ratchet on the right side of the fifth-gear main shaft gear 15; meanwhile, the second shift driving lever 42 drives the second double-ratchet wheel 19 to move leftwards, and the ratchet on the left side of the second double-ratchet wheel 19 is meshed with the ratchet on the right side of the fourth-gear main shaft gear 14; the four-gear main shaft gear 14 drives the four-gear auxiliary shaft gear 24 to rotate, the four-gear auxiliary shaft gear 24 drives the auxiliary shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct-drive gear 12 which is sleeved on the main shaft 1 to rotate, and the output chain wheel 3 rotates;

8) When the gear is shifted down from the fourth gear to the third gear, the gear shifting drum wheel 4 is rotated reversely, the second gear shifting rod 43 drives the second double-ratchet wheel 19 to move rightwards, and the ratchet on the left side of the second double-ratchet wheel 19 is separated from the ratchet on the right side of the fourth-gear main shaft gear 14; meanwhile, the first shift deflector rod 41 drives the first double-ratchet wheel 18 to move rightward, and the ratchet on the right side of the first double-ratchet wheel 18 is meshed with the ratchet on the left side of the third-gear main shaft gear 13; the three-gear main shaft gear 13 drives the three-gear auxiliary shaft gear 23 to rotate, the three-gear auxiliary shaft gear 23 drives the auxiliary shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct-drive gear 12 which is sleeved on the main shaft 1 to rotate, and the output chain wheel rotates;

9) When the gear is shifted down from the third gear to the second gear, the gear shifting drum 4 is rotated reversely, the first gear shifting deflector rod 41 drives the first double-ratchet wheel 18 to move leftwards, and the ratchet on the right side of the first double-ratchet wheel 18 is separated from the ratchet on the left side of the third-gear main shaft gear 13; meanwhile, the second shift deflector rod 42 drives the second double-ratchet wheel 19 to move rightwards, and the ratchet on the right side of the second double-ratchet wheel 19 is meshed with the ratchet on the left side of the direct drive gear 12; the direct drive gear 12 directly rotates through the output chain wheel 3 fixed on the direct drive gear 12.

10 When the gear shift drum 4 is rotated reversely in a downshift state from the second gear to the first gear, the second shift lever 42 drives the second double-ratchet wheel 19 to move leftward, and the ratchet teeth on the right side of the second double-ratchet wheel 19 are separated from the ratchet teeth on the left side of the direct drive gear 12; at the same time, the third shift lever 43 drives the single ratchet 28 to move leftward, the ratchet teeth on the left side of the single ratchet wheel 28 are meshed with the ratchet teeth on the right side of the first-gear counter shaft gear 21; the first-gear main shaft gear 21 drives the first-gear auxiliary shaft gear 21 to rotate, the first-gear auxiliary shaft gear 21 drives the auxiliary shaft 2 and the reverse gear 22 to rotate, the reverse gear 22 drives the direct-drive gear 12 which is sleeved on the main shaft 1 to rotate, and the output chain wheel 3 rotates;

11 When a downshift from first gear to neutral gear occurs, the shift drum 4 is rotated in reverse, and the first double-ratchet 18, the second double-ratchet 19, and the shift drum are still in the disengaged state; the gear shifting drum wheel 4 controls the third gear shifting deflector rod 43 to drive the single ratchet wheel 28 to move rightwards, and the single ratchet wheel 28 is in a separation state;

12 In different initial states, the ratchet engagement position corresponds to the specific state described above. The description of the embodiments is only for the purpose of helping to understand the method of the present invention and its core idea, and it should be noted that it is obvious to those skilled in the art that several modifications and modifications can be made to the invention without departing from the principle of the present invention, such as simply changing the length of the bushing and the tooth flank inclination angle, the number of teeth of the gear ratchet and the number of teeth of the sleeve ratchet, and these modifications and modifications also fall within the protection scope of the claims of the present invention.

Claims (8)

1. A compact bicycle middle shaft gearbox with load speed change comprises a box type speed change device and a gear shifting device, wherein the box type speed change device comprises a box body, a main shaft, an auxiliary shaft and an output chain wheel, a plurality of main shaft gears and driving ratchet wheels are arranged on the main shaft, a plurality of auxiliary shaft gears and driven ratchet wheels are arranged on the auxiliary shaft, a shifting groove is formed in the middle of each driving ratchet wheel and each driven ratchet wheel, and the main shaft gears and the auxiliary shaft gears are mutually matched and meshed; the gear shifting device comprises a gear shifting drum, a gear shifting driving lever and a gear shifting fork, wherein the gear shifting drum is rotationally fixed on the box body, two ends of a main shaft and an auxiliary shaft are installed on the box body through bearings, the gear shifting driving lever can move left and right and is fixed on the box body, the rotating central line of the gear shifting drum is parallel to the rotating central line of the auxiliary shaft, a gear shifting drum groove is formed in the circumferential surface of the gear shifting drum, the gear shifting fork comprises a shifting fork part of a lower section and a shifting fork connecting part of an upper section, the shifting fork part is clamped in a shifting groove in the middle of a ratchet wheel, the front end of the gear shifting driving lever is movably fixed in the gear shifting drum groove, and the rear end of the gear shifting driving lever is movably connected with the shifting fork connecting part and is characterized in that: one of the main shaft gears is a direct-drive gear, and the output chain wheel is fixed on the direct-drive gear; at least one of the driving ratchet wheel and the driven ratchet wheel is a double-ratchet wheel, two main shaft gears or two auxiliary shaft gears with single ratchet are arranged on two sides of the double-ratchet wheel, the double-ratchet wheel moves left and right on the main shaft or the auxiliary shaft and is respectively meshed with or separated from the two main shaft gears or the two auxiliary shaft gears of the single ratchet through the ratchets on the two sides; and the shifting deflector rod and the shifting fork are elastic connecting pieces.

2. The compact, variable speed, bicycle bottom bracket bearing gear box of claim 1, wherein: the elastic connecting piece is a metal elastic piece, the upper end of the metal elastic piece is fixedly connected to the gear shifting lever, and the lower end of the metal elastic piece movably clamps the gear shifting lever.

3. The compact, variable speed, bicycle bottom bracket bearing gear box of claim 1, wherein: the elastic connecting piece is a torsion spring, the torsion spring comprises a torsion spring body and a torsion spring output end, the torsion spring body is fixedly connected to the gear shifting lever, and the gear shifting lever is movably clamped by the torsion spring output end.

4. The compact, variable speed, bicycle bottom bracket bearing gear box of claim 1, wherein: the shifting device further comprises a fixing plate and a shifting fork guide rod, the fixing plate is fixed on the box body, the shifting fork guide rod is fixed on the fixing plate or directly fixed on the box body, the shifting fork connecting portion is a hollow tube, and the hollow tube is movably sleeved on the shifting fork guide rod.

5. A load shifting, compact bottom bracket bearing on a bicycle as defined in claim 2 or 3, wherein: the gearbox is a five-gear gearbox, a first-gear main shaft gear, a fifth-gear main shaft gear, a third-gear main shaft gear, a fourth-gear main shaft gear and a direct-drive gear are arranged on the main shaft from left to right, a first double-ratchet wheel is arranged between the fifth-gear main shaft gear and the third-gear main shaft gear, second double-ratchet wheels are arranged between the fourth-gear main shaft gear and the direct-drive gear, the first-gear main shaft gear is fixedly connected to the main shaft, the fifth-gear main shaft gear, the third-gear main shaft gear, the fourth-gear main shaft gear and the direct-drive gear are sleeved on the main shaft in an empty mode, and the first double-ratchet wheel and the second double-ratchet wheel are sleeved on the main shaft in a sliding mode; the auxiliary shaft is provided with a first-gear auxiliary shaft gear, a fifth-gear auxiliary shaft gear, a third-gear auxiliary shaft gear, a fourth-gear auxiliary shaft gear and a reverse gear from left to right, a single-ratchet wheel is arranged between the first-gear auxiliary shaft gear and the fifth-gear auxiliary shaft gear, the first-gear auxiliary shaft gear is sleeved on the auxiliary shaft in a free mode, and the fifth-gear auxiliary shaft gear, the third-gear auxiliary shaft gear, the fourth-gear auxiliary shaft gear and the reverse gear are fixedly connected to the auxiliary shaft.

6. The compact, variable speed, bicycle bottom bracket bearing gear box of claim 5, wherein: the shift deflector rod and the shift fork are three, wherein the first shift deflector rod controls the first double-ratchet wheel, the second shift deflector rod controls the second double-ratchet wheel, and the third shift deflector rod controls the single-ratchet wheel.

7. The compact, variable speed, bicycle bottom bracket bearing gear box of claim 6, wherein: the ratchet teeth are all helical teeth.

8. The method of claim 7,

1) When the gearbox is in the neutral position, the first double-ratchet wheel, the second double-ratchet wheel and the single-ratchet wheel are all in a separated state with the corresponding gear;

2) When the gear is shifted from the neutral gear to the first gear, the gear shifting drum wheel controls the third gear shifting deflector rod to drive the single ratchet wheel to move leftwards, the ratchet on the left of the single ratchet wheel is meshed with the ratchet on the right of the first-gear counter shaft gear; the other ratchet wheels are in a separated state, the main shaft drives the first-gear main shaft gear to rotate, the first-gear main shaft gear drives the first-gear auxiliary shaft gear, the auxiliary shaft and the reverse gear to rotate, and the reverse gear drives the direct-drive gear on the main shaft to rotate so as to realize the rotation of the output chain wheel;

3) When the gear is shifted from the first gear to the second gear, the gear shifting drum wheel is rotated, the third gear shifting deflector rod drives the single-ratchet wheel to move rightwards, and the ratchet on the left side of the single-ratchet wheel is separated from the ratchet on the right side of the first-gear counter shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move to the right, and the ratchet on the right of the second double-ratchet wheel is meshed with the ratchet on the left of the direct drive gear; the power directly rotates through an output chain wheel fixed on the direct drive gear, and the first double-ratchet wheel and the single-ratchet wheel are both in a ratchet separation state;

4) When the gear is shifted from the second gear to the third gear, the gear shifting drum wheel is rotated, the second gear shifting deflector rod drives the second double-ratchet wheel to move leftwards, and the ratchet on the right of the second double-ratchet wheel is separated from the ratchet on the left of the direct drive gear; meanwhile, the first gear shifting deflector rod drives the first double-ratchet wheel to move rightwards, the ratchet on the right side of the first double-ratchet wheel is meshed with the ratchet on the left side of the third-gear main shaft gear, the third-gear main shaft gear drives the third-gear auxiliary shaft gear to rotate, the third-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct drive gear on the main shaft to rotate, and the output chain wheel rotates;

5) When the gear is shifted from the third gear to the fourth gear, the gear shifting drum wheel is rotated, the first gear shifting driving lever drives the first double-ratchet wheel to move leftwards, and the ratchet on the right side of the first double-ratchet wheel is separated from the ratchet on the left side of the third-gear main shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move leftwards, the ratchet positioned on the left side of the second double-ratchet wheel is meshed with the ratchet on the right side of the fourth-gear main shaft gear, the fourth-gear main shaft gear drives the fourth-gear counter shaft gear to rotate, the fourth-gear counter shaft gear drives the counter shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear on the main shaft to rotate, and the output chain wheel rotates;

6) When the gear is shifted from the fourth gear to the fifth gear, the gear shifting drum wheel is rotated, the second gear shifting deflector rod drives the second double-ratchet wheel to move rightwards, and the ratchet on the left side of the second double-ratchet wheel is separated from the ratchet on the right side of the fourth-gear main shaft gear; meanwhile, the first gear shifting deflector rod drives the first double-ratchet wheel to move leftwards, and the ratchet on the left side of the first double-ratchet wheel is meshed with the ratchet on the right side of the fifth-gear main shaft gear; the five-gear main shaft gear drives the five-gear auxiliary shaft gear to rotate, the five-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct drive gear on the main shaft to rotate, and the output chain wheel rotates;

7) When the gear is shifted down from the fifth gear to the fourth gear, the gear shifting drum wheel is rotated reversely, the first gear shifting deflector rod drives the first double-ratchet wheel to move rightwards, and the ratchet on the left of the first double-ratchet wheel is separated from the ratchet on the right of the fifth-gear main shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move leftwards, and the ratchet on the left side of the second double-ratchet wheel is meshed with the ratchet on the right side of the fourth-gear main shaft gear; the four-gear main shaft gear drives the four-gear auxiliary shaft gear to rotate, the four-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct drive gear on the main shaft to rotate, and the output chain wheel rotates;

8) When the gear is shifted down from the fourth gear to the third gear, the gear shifting drum wheel is rotated reversely, the second gear shifting deflector rod drives the second double-ratchet wheel to move rightwards, and the ratchet on the left of the second double-ratchet wheel is separated from the ratchet on the right of the fourth-gear main shaft gear; meanwhile, the first gear shifting driving lever drives the first double-ratchet wheel to move rightwards, and the ratchet on the right side of the first double-ratchet wheel is meshed with the ratchet on the left side of the third-gear main shaft gear; the three-gear main shaft gear drives the three-gear auxiliary shaft gear to rotate, the three-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear on the main shaft to rotate, and the output chain wheel rotates;

9) When the gear is shifted from the third gear to the second gear, the gear shifting drum wheel is rotated reversely, the first gear shifting driving lever drives the first double-ratchet wheel to move leftwards, and the ratchet on the right side of the first double-ratchet wheel is separated from the ratchet on the left side of the third-gear main shaft gear; meanwhile, the second gear shifting driving lever drives the second double-ratchet wheel to move rightwards, and the ratchet on the right side of the second double-ratchet wheel is meshed with the ratchet on the left side of the direct drive gear; the direct drive gear directly rotates through an output chain wheel fixed on the direct drive gear.

10 When the gear is shifted down from the second gear to the first gear, the gear shifting drum wheel is rotated reversely, the second gear shifting deflector rod drives the second double-ratchet wheel to move leftwards, and the ratchet on the right side of the second double-ratchet wheel is separated from the ratchet on the left side of the direct drive gear; meanwhile, the third gear shifting deflector rod drives the single ratchet wheel to move leftwards, the ratchet positioned on the left side of the single ratchet wheel is meshed with the ratchet on the right side of the first-gear counter shaft gear; the first-gear main shaft gear drives the first-gear auxiliary shaft gear to rotate, the first-gear auxiliary shaft gear drives the auxiliary shaft and the reverse gear to rotate, the reverse gear drives the direct-drive gear on the main shaft to rotate, and the output chain wheel rotates;

11 When a downshift from a first gear to a neutral gear is performed, the shift drum is rotated in reverse, and the first double-ratchet wheel, the second double-ratchet wheel and the shift drum are still in a disengaged state; the gear shifting drum wheel controls the third gear shifting deflector rod to drive the single ratchet wheel to move rightwards, and the single ratchet wheel is in a separated state;

and circulating, wherein in different initial states, the ratchet wheel combination positions correspond to different specific states.

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