Speed control system

Abstract

The utility model discloses a speed control system. Comprising a base; the input unit comprises an input shaft arranged on the base and an input gear arranged on the input shaft, and the input shaft is in transmission connection with the power source; the output unit comprises a first output gear rotationally arranged on the base, a gear set in transmission connection with the first output gear and a second output gear in transmission connection with the gear set, and the second output gear outputs power through an output shaft; the input gear is shifted through shifting of the shifting fork so that the input gear can be in transmission connection with the first output gear, any gear unit and the second output gear. Gear shifting can be achieved by pushing the input gear to transversely move to the corresponding output gear through the shifting fork, gear shifting is smooth, response is rapid, torque is high, the lower output unit is matched with a newly-designed special-shaped gear structure, the structure is simpler and more compact, cost is low, maintenance is convenient, and the service life is long.

Description

Technical Field

[0001] The utility model relates to the technical field of vehicle speed change systems, in particular to a speed change system. Background Art

[0002] A sequential manual gearbox (SMG) differs from a standard manual transmission in its operation: shifting up and down is accomplished by simply pushing and pulling the gear lever forward and backward. This design not only speeds up shifts but also significantly reduces the possibility of mis-shifting.

[0003] Traditional sequential gearboxes, such as the public patent document CN221120799U, have an input shaft and an output shaft, each of which has a number of gears whose axes are aligned with their respective axes. Among these gears, their sizes and shapes are different. Some gears contain spline teeth inside, which can mesh with the splines on the shaft and slide left and right; another part of the gears is fixed to the shaft by needle rollers to ensure that it will not slide left and right while idling. The idling gears have grooves on the sides to ensure that the dog teeth on the spline gears can slide into the grooves and engage with each other.

[0004] When in working state, the spline gear slides to the corresponding idle gear and locks it, so that the output shaft rotates with this gear and transmits power. For different gears, different spline teeth and different idle gears need to cooperate with each other. At the same time, in actual applications, a ratchet with several grooves is often required. The increase or decrease of gears is to rotate the ratchet. When the ratchet rotates, the shift mechanism stuck in the groove will move. The ratchet is used to control multiple sets of shift forks at the same time, and to engage another set of gears while one set of gears is separated, so as to achieve the effect of almost no shift gap.

[0005] The advantages of this design are smaller size, faster shifting time and better transmission efficiency, but its disadvantages are also obvious:

[0006] During the gear shifting process, it cannot skip gears like other transmissions, but can only gradually increase or decrease gears; the noise is particularly loud, and the special design of the dog clutch makes the transmission less durable; the gear shifting is uncomfortable and jerky, so it is often only suitable for racing cars.

[0007] To this end, the applicant has proposed this application, aiming to retain the advantages of the sequential gearbox while eliminating its disadvantages. Utility Model Content

[0008] The utility model discloses in view of the deficiency in the prior art, provides a variable speed system, it is through the shift fork and promotes the input gear to move horizontally to the corresponding output gear place just can realize gear shifting, gear shifting is smooth, reacts quickly, high torque, and adopts the new design of the special-shaped gear structure cooperation at the lower output unit, and the structure is simpler, and the cost is low, and the maintenance is convenient, and the structure is compact, on the basis of possessing the advantage of the sequential gearbox, and the shortcoming is eliminated.

[0009] To solve the above technical problems, the utility model solves through the following technical schemes:

[0010] A variable speed system, comprising

[0011] Base;

[0012] Input unit, it includes the input shaft who configures in the base and can rotate relative to the base and the input gear who can move horizontally and configures in the input shaft and rotates with it, the input shaft is transmission connection with power source, and

[0013] Output unit, it includes the first output gear who rotates and configures in the base, the gear set that is transmission connection with the first output gear and the second output gear that is transmission connection with the gear set, the second output gear is through the output shaft and exports power;

[0014] The gear set includes several gear units that are transmission connection in sequence, to form the gear layout that the first output gear, several gear units to the second output gear diameter reduces in turn;

[0015] The input gear is through the shift fork and is shifted to shift, to make it can be transmission connection with the first output gear, any gear unit and the second output gear.

[0016] In the above technical scheme, preferably, the first transmission tooth that rotates with it is configured on the first output gear, all the gear unit includes the main gear, the first inner tooth portion that configures on the main gear and the second transmission tooth that rotates with the main gear, and the second output gear includes the second inner tooth portion;

[0017] The first output gear and the gear unit between adjacent are transmission connection through the cooperation of the first transmission tooth and the first inner tooth portion;

[0018] The gear unit between adjacent two is transmission connection through the cooperation of the second transmission tooth and the corresponding first inner tooth portion between adjacent;

[0019] The second output gear and the gear unit between adjacent are transmission connection through the cooperation of the second transmission tooth and the second inner tooth portion.

[0020] In the above technical solution, preferably, the teeth on the first transmission tooth, the first internal tooth portion, the second transmission tooth and the second internal tooth portion are straight teeth or helical teeth.

[0021] In the above technical solution, preferably, a first support seat is arranged on the base, a first extension shaft is horizontally extended on the first output gear and passes through the first support seat, the first transmission tooth is arranged at the outer end of the first extension shaft, and a one-way bearing is arranged between the first support seat and the first extension shaft.

[0022] In the above technical solution, preferably, the base is provided with a second support seat for supporting the gear unit, the main gear is laterally extended with a second extension shaft passing through the second support seat, and the second transmission tooth is arranged at the outer end of the second extension shaft.

[0023] In the above technical solution, preferably, a one-way bearing is arranged between the second support seat and the second extension shaft;

[0024] A first circular inner cavity concentric with the main gear is formed on the side wall thereof, and the first inner tooth portion is arranged on the circular side wall of the first circular inner cavity;

[0025] A second circular inner concave cavity concentric with the second output gear is formed on the side wall of the second output gear, and the second inner tooth portion is arranged on the circular side wall of the second circular inner concave cavity.

[0026] In the above technical solution, preferably, the first output gear is concentric with the first extension shaft and the first transmission tooth;

[0027] The outer diameter of the main gear gradually decreases from close to the first output gear to away from it. The main gear, second extension shaft, and second transmission tooth on the same gear unit are concentric. The second extension shaft is concentric with the corresponding mounting hole on the second support base, so that the center heights of the mounting holes of the second support bases matched with different gear units are different.

[0028] In the above technical solution, preferably, a support shaft is arranged on the base, and a plurality of support gears meshing with the main gear of the gear unit are arranged on the support shaft.

[0029] In the above technical solution, preferably, two groups of support shafts are configured on the base, which are respectively arranged on the front side and the rear side of the gear unit;

[0030] The number of the supporting gears is consistent with the number of the main gears;

[0031] A first circular inner cavity concentric with the main gear is formed on the side wall thereof, and the first inner tooth portion is arranged on the circular side wall of the first circular inner cavity;

[0032] A second circular inner cavity concentric with the second output gear is formed on the side wall thereof, and the second inner tooth portion is provided on the circular side wall of the second circular inner cavity;

[0033] The first transmission teeth are formed on the side wall of the first output gear, and the thickness thereof is adapted to the depth of the corresponding first circular inner cavity to reduce the gap between the first output gear and the adjacent gear unit;

[0034] The second transmission teeth are formed on the side wall of the main gear, and the thickness thereof is adapted to the depth of the corresponding first circular inner cavity to reduce the gap between two adjacent gear units;

[0035] The depth of the second circular inner cavity is adapted to the thickness of the corresponding second transmission tooth, so as to reduce the gap between the gear unit and the second output gear.

[0036] In the above technical solution, preferably, the input gear is located above the first output gear, all the gear units and the second output gear;

[0037] The upper edges of the first output gear, all the gear units and the second output gear are flush with each other;

[0038] The base is provided with a connecting shaft, and the first output gear is rotatable relative to the base via the connecting shaft;

[0039] The horizontal position of the output shaft is higher than the horizontal position of the connecting shaft.

[0040] The beneficial effects of the utility model are:

[0041] The utility model can realize gear shifting by pushing the input gear to move horizontally to the corresponding output gear through the shift fork, which has smooth gear shifting, quick response and high torque. The newly designed special-shaped gear structure is used at the output unit below, which has a simpler and more compact structure, low cost, easy maintenance and long service life.

[0042] The design of the support seat or support gear can ensure the transmission stability of the transmission gear in the middle part, and the design of the helical gear helps to reduce noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of Example 1 of the present utility model.

[0044] Figure 2 This is a top view schematic diagram of Example 1 of the utility model.

[0045] Figure 3It is the cross section schematic view of the embodiment 1 of the utility model.

[0046] Figure 4 It is the first output gear schematic view of the embodiment 1 of the utility model.

[0047] Figure 5 It is the gear unit schematic view of the embodiment 1 of the utility model.

[0048] Figure 6 It is the second output gear schematic view of the embodiment 1 of the utility model.

[0049] Figure 7 It is the support seat schematic view of the embodiment 1 of the utility model.

[0050] Figure 8 It is the schematic view of the embodiment 2 of the utility model.

[0051] Figure 9 It is the overhead schematic view of the embodiment 2 of the utility model.

[0052] Figure 10 It is the cross section schematic view of the embodiment 2 of the utility model.

[0053] Figure 11 It is the first output gear schematic view of the embodiment 2 of the utility model.

[0054] Figure 12 It is the gear unit schematic view of the embodiment 2 of the utility model.

[0055] Figure 13 It is the second output gear schematic view of the embodiment 2 of the utility model.

[0056] Figure 14 It is the support shaft and support gear cooperation state schematic view of the embodiment 2 of the utility model. DETAILED DESCRIPTION

[0057] The utility model will be further described in detail in combination with the specific embodiments and the accompanying drawings: Embodiment 1

[0058] Referring to Figure 1-Figure 7 A variable speed system, including base 1, be provided with input unit and output unit on base 1, base 1 as load-bearing component, can be housing type component or only to the end of relevant shaft support component, when it is housing type component, it can include cover for accommodating relevant transmission structure in, as housing type component.

[0059] As Figure 1 The shown style is one of the implementation of base, including bottom plate 11 and at least two vertical plates 12, such as Figure 1The arrangement of four vertical panels 12 is one embodiment.

[0060] The input unit includes an input shaft 21 and an input gear 22. The input shaft 21 is connected to the power source by transmission, wherein the input shaft 21 is assembled on the base 1. As one embodiment, the input shaft 21 is passed through the vertical plate 12, such as being passed through two or more vertical plates 12, and supported by multiple vertical plates 12. At the same time, the input shaft 21 can also rotate relative to the vertical plate 12, such as directly passing the input shaft 21 through the vertical plate 12.

[0061] The input gear 22 is assembled on the input shaft 21. It can move laterally on the input shaft 21 and rotate synchronously with the input shaft 21. The lateral movement of the input gear 22 depends on the shift fork (not shown in the figure). For the shift fork, please refer to the existing design.

[0062] As for the connection method between the input shaft 21 and the input gear 22, as one embodiment, the input shaft 21 and the input gear 22 are key-connected, and the outer wall of the input shaft 21 has a plurality of axially extending key strips, and the inner hole wall of the input gear 22 has a groove body that matches the key strips. If the outer wall of the input shaft 21 is circumferentially evenly distributed with the key strips, the groove body is also circumferentially evenly distributed on the inner hole wall of the input gear 22. In this form, the inner hole wall of the input gear 22 presents an inner gear ring shape.

[0063] As for the output unit, it includes a first output gear 3, a gear group and a second output gear 4, wherein the gear group is transmission-connected to the first output gear 3, and includes several gear units 5 transmission-connected in sequence. As one embodiment, the output unit is arranged as a whole below the input unit, and is arranged in sequence by the first output gear 3, several gear units 5 and the second output gear 4, corresponding to multiple gears. When the input gear 22 is transmission-connected to the first output gear 3, it corresponds to the first gear; when the input gear 22 is transmission-connected to the gear unit 5 next to the first output gear 3, it corresponds to the second gear; and so on until the input gear 22 is transmission-connected to the second output gear 4, it corresponds to the last gear. If three gear units 5 are provided, the gear is the fifth gear; if four gear units 5 are provided, the gear is the sixth gear, and so on.

[0064] The first output gear 3 is configured on the base 1. If a connecting shaft 31 is provided on the corresponding vertical plate 12, the first output gear 3 is rotatable relative to the vertical plate 12 through the connecting shaft 31. The first output gear 3 can be fixedly connected to the connecting shaft 31, and the connecting shaft 31 is rotatably provided on the vertical plate 12; or the connecting shaft 31 is fixedly provided on the vertical plate 12, and the first output gear 3 is rotatably provided on the connecting shaft 31.

[0065] In the embodiment, the first output gear 3 is provided with a first transmission gear 32 rotating synchronously with the first output gear 3, as shown in the figure. Figure 4 As shown in the figure, the first output gear 3 is provided with a first extension shaft 33 extending laterally on the side wall of the first output gear 3, and the first transmission gear 32 is arranged at the outer end of the first extension shaft 33, so that the first transmission gear 32 rotates synchronously with the first output gear 3. The first output gear 3, the first extension shaft 33 and the first transmission gear 32 can be fixed by welding or integrally formed, etc.

[0066] In the embodiment, the first output gear 3 is concentrically arranged with the first extension shaft 33 and the first transmission gear 32.

[0067] As shown in the figure, Figure 1-3 The first support seat 6 is mounted on the bottom plate 11, and the mounting mode can be fixed by welding or fastening, etc. The first support seat 6 includes a through hole, and the first extension shaft 33 is arranged in the through hole. When the first output gear 3, the first extension shaft 33 and the first transmission gear 32 are integrally formed, the upper end of the first support seat 6 can be designed to be expandable, such as being rotatably connected to the main part of the first support seat 6, and then being locked by fastening or the like. After the upper end is opened, the first extension shaft 33 can be assembled into the through hole. When the first output gear 3, the first extension shaft 33 and the first transmission gear 32 are fixed by welding or the like, the first transmission gear 32 can be fixed on the first extension shaft 33 after the first extension shaft 33 passes through the through hole.

[0068] In the embodiment, a one-way bearing 61 is arranged between the first extension shaft 33 and the through hole wall of the first support seat 6. The outer ring of the one-way bearing 61 is matched with the hole diameter of the through hole, and the inner ring of the one-way bearing 61 is matched with the outer diameter of the first extension shaft 33. The one-way bearing 61 can be used to prevent the problem of jamming during gear shifting. The problem of jamming mainly results from the fact that the rotating speeds of different gears are not consistent during gear shifting, and the one-way bearing can effectively solve this technical problem.

[0069] The gear unit 5 includes a main gear 51, a first inner tooth part 52 and a second transmission gear 53. As one of the embodiments, as shown in the figure, Figure 5 A first circular inner cavity 54 concentric with the main gear 51 is formed on the side wall of the main gear 51, and the first inner tooth part 52 is arranged on the circular side wall of the first circular inner cavity 54. The first inner tooth part 52 of the gear unit 5 adjacent to the first output gear 3 is in transmission connection with the first transmission gear 32, as shown in the figure. Figure 3 The first transmission gear 32 is arranged at the lower part of the first circular inner cavity 54 and is in meshing engagement with the lower part of the first inner tooth part 52, so that the gear unit 5 and the first output gear 3 are in transmission connection.

[0070] As shown in the figure, Figure 5As shown, the second extension shaft 55 is horizontally extended on the side wall of the main gear 51, and the second transmission gear 53 is arranged at the outer end of the second extension shaft 55, so that the second transmission gear 53 rotates synchronously with the main gear 51, wherein the main gear 51, the second extension shaft 55 and the second transmission gear 53 can be fixed by welding or integrally formed.

[0071] As shown in the drawings, Figure 1-3 A second support seat 62 is arranged on the bottom plate 11, which can be fixed by welding or fasteners, and is used to support the gear unit 5. As an embodiment, the second support seat 62 has the same structure as the first support seat 6.

[0072] The second support seat 62 has a through hole, and the second extension shaft 55 passes through the through hole. When the main gear 51, the second extension shaft 55 and the second transmission gear 53 are integrally formed, the upper end of the second support seat 62 can be designed to be expandable, such as rotatingly connected to the main part of the second support seat 62, and then locked by fasteners. After the upper end is opened, the second extension shaft 55 can be assembled into the through hole. When the main gear 51, the second extension shaft 55 and the second transmission gear 53 are fixed by welding, the second transmission gear 53 can be fixed on the second extension shaft 55 after the second extension shaft 55 passes through the through hole.

[0073] In this embodiment, a one-way bearing 61 is arranged between the second extension shaft 55 and the through hole wall of the second support seat 62. The outer ring of the one-way bearing 61 is matched with the hole diameter of the through hole, and the inner ring of the one-way bearing 61 is matched with the outer diameter of the second extension shaft 55. The one-way bearing has the same function as the one-way bearing on the first support seat 6.

[0074] As shown in the drawings, Figure 1 , Figure 2 A plurality of gear units 5 are arranged in sequence, and each gear unit 5 is provided with a corresponding second support seat 62. The adjacent gear units 5 are connected by the cooperation of the second transmission gear 53 and the corresponding first inner tooth part 52 to form a transmission connection. Figure 3 As shown in the drawings, the second transmission gear 53 is arranged below the corresponding first circular concave cavity 54 and is engaged with the lower teeth of the corresponding first inner tooth part 52.

[0075] In this embodiment, the outer diameter of the main gear 51 gradually decreases from the first output gear 3 to the second output gear 4, that is, the diameter of the first output gear 3 is the largest, and the diameter gradually decreases from the first output gear 3 to the second output gear 4. The upper edges of the first output gear 3, the main gears 51 of all gear units 5 and the second output gear 4 are flush, so that the input gear 22 only needs to move horizontally to engage with any gear to switch different gears.

[0076] In this embodiment, the main gear 51, the second extension shaft 55 and the second transmission tooth 53 on the same gear unit 5 are concentric, and the second extension shaft 55 is concentric with the through hole on the corresponding second support seat 62, so that the center heights of the mounting holes of the second support seats 62 matched with different gear units 5 are different, such as Figure 3 shown.

[0077] The second output gear 4 is connected to the gear set in a transmission manner. Specifically, Figure 6 As shown, a second circular inner cavity 41 concentric therewith is opened on the side wall of the second output gear 4, and a second inner tooth portion 42 is provided on the circular side wall of the second circular inner cavity 41. The second transmission teeth 53 of the gear unit 5 adjacent to the second output gear 4 are transmission-connected with the second inner tooth portion 42. For example, the second transmission teeth 53 are arranged at the lower part of the second circular inner cavity 41 and mesh with the teeth at the lower part of the second inner tooth portion 42, so that the second output gear 4 and the gear unit 5 form a transmission connection relationship, as shown in FIG. Figure 3 shown.

[0078] In this embodiment, Figure 1-Figure 3 、 Figure 6 As shown, the outer side wall of the second output gear 4 is connected to an output shaft 43 that rotates synchronously with it. The output shaft 43 is rotatably installed on the corresponding vertical plate 12 to output power through the output shaft 43. The output shaft 43 and the second output gear 4 can be welded or integrally formed.

[0079] In this embodiment, the teeth on the first transmission tooth 32, the first inner tooth portion 52, the second transmission tooth 53 and the second inner tooth portion 42 are straight teeth or helical teeth, preferably helical teeth, which can further reduce the noise generated during transmission.

[0080] In this embodiment, Figure 3 As shown, the horizontal position of the output shaft 43 is higher than the horizontal position of the connecting shaft 31.

[0081] The power is input by the input shaft 21 connected to the power source, driving the input gear 22 to rotate. When the input gear 22 is connected to the first output gear 3, it is the first gear. While the first output gear 3 rotates, all the gear units 5 and the second output gear 4 rotate synchronously, and finally the power is output through the output shaft 43; when the input gear 22 is connected to any main gear 51 or the second output gear 4, it is the other gears, with the first gear of the first output gear 3 having the largest torque, and the gear increases and the torque decreases in sequence towards the second output gear 4; when the input gear 22 is not connected to the first output gear 3, any main gear 51 and the second output gear 4, it is neutral. Example 2

[0082] The main difference between this embodiment and embodiment 1 is the different support method for the gear unit 5. The rest are the same. For the description of the same parts, please refer to embodiment 1.

[0083] like Figures 8-14 As shown, a support shaft 71 is disposed on the vertical plate 12 of the base 1, and a plurality of support gears 72 meshing with the main gear 51 of the gear unit 5 are disposed on the support shaft 71. The support gears 72 can rotate along with the main gear 51 when the main gear 51 rotates. The support gears 72 can be rotatably arranged on the support shaft 71. The diameter of the support gear 72 is determined according to the size of the corresponding main gear 51. The larger the corresponding main gear 51, the smaller the corresponding support gear 72. The layout is as follows: Figure 8 、 Figure 9 、 Figure 14 shown.

[0084] As one embodiment, two sets of support shafts 71 are configured on the vertical plate 12 of the base 1, which are respectively arranged on the front side and the rear side of the gear unit 5. Figure 9 as shown to improve the support effect.

[0085] In this embodiment, the number of the supporting gears 72 on a single side is consistent with the number of the main gears 51 , ensuring that each main gear 51 can be effectively supported.

[0086] Due to the different support method of the gear unit 5, this embodiment is different from embodiment 1. The spacing between the first output gear 3 and the adjacent gear unit 5, between two adjacent gear units 5, and between the second output gear 4 and the adjacent gear unit 5 can be greatly reduced, the overall structure is more compact, and the shifting speed is faster. Figures 8-10 shown.

[0087] Specifically, such as Figure 10 、 Figure 11 As shown, the first transmission tooth 32 is formed on the side wall of the first output gear 3, and the first extension shaft 33 is no longer provided. The thickness of the first transmission tooth 32 is adapted to the depth of the corresponding first circular inner cavity 54 to reduce the gap between the first output gear 3 and the adjacent gear unit 5.

[0088] like Figure 10 、 Figure 12 As shown, the second transmission teeth 53 are formed on the side wall of the main gear 51, and the second extension shaft 55 is no longer provided. The thickness of the second transmission teeth 53 is adapted to the depth of the corresponding first circular inner cavity 54 to reduce the gap between the two adjacent gear units 5.

[0089] like Figure 10 、 Figure 13As shown, the depth of the second circular inner cavity 41 is adapted to the thickness of the corresponding second transmission tooth 53 to reduce the gap between the gear unit 5 and the second output gear 4 .

[0090] In this embodiment, similar to the one-way bearings 61 provided on the first support seat 6 and the second support seat 62 in embodiment 1, one-way bearings are provided at corresponding positions, such as between the support gear 72 and the support shaft 71 .

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A speed change system, characterized in that: include base; an input unit comprising an input shaft disposed on the base and rotatable relative to the base, and an input gear disposed on the input shaft and capable of lateral movement and synchronously rotating therewith, wherein the input shaft is transmission-connected to a power source; as well as An output unit comprising a first output gear rotatably disposed on the base, a gear set transmission-connected to the first output gear, and a second output gear transmission-connected to the gear set, wherein the second output gear outputs power via an output shaft; The gear set includes a plurality of gear units that are sequentially connected to form a gear layout with diameters decreasing sequentially from the first output gear, the plurality of gear units to the second output gear; The input gear is shifted by a shift fork so as to be in transmission connection with the first output gear, any of the gear units and the second output gear.

2. A speed change system according to claim 1, characterized in that: The first output gear is provided with a first transmission tooth that rotates synchronously therewith, and all the gear units include a main gear, a first internal tooth portion provided on the main gear, and a second transmission tooth that rotates synchronously therewith, and the second output gear includes a second internal tooth portion; The first output gear and the adjacent gear unit are connected to each other through the cooperation of the first transmission teeth and the first internal gear portion. Two adjacent gear units are connected to each other through the cooperation of the second transmission teeth and the corresponding first internal gear portions; The second output gear and the adjacent gear unit are connected in a transmission manner through the cooperation between the second transmission teeth and the second internal gear portion.

3. A speed change system according to claim 2, characterized in that: The teeth on the first transmission tooth, the first internal tooth portion, the second transmission tooth and the second internal tooth portion are straight teeth or helical teeth.

4. A speed change system according to claim 2, characterized in that: A first support seat is arranged on the base, a first extension shaft is extended transversely from the first output gear and passes through the first support seat, the first transmission tooth is arranged on the outer end of the first extension shaft, and a one-way bearing is arranged between the first support seat and the first extension shaft.

5. A speed change system according to any one of claims 2 to 4, characterized in that: The base is provided with a second support base for supporting the gear unit. A second extension shaft extending transversely from the main gear and penetrating the second support base is provided. The second transmission tooth is provided at the outer end of the second extension shaft.

6. A speed change system according to claim 5, characterized in that: A one-way bearing is disposed between the second support seat and the second extension shaft; A first circular inner cavity concentric with the main gear is formed on the side wall thereof, and the first inner tooth portion is arranged on the circular side wall of the first circular inner cavity; A second circular inner concave cavity concentric with the second output gear is formed on the side wall of the second output gear, and the second inner tooth portion is arranged on the circular side wall of the second circular inner concave cavity.

7. The speed change system according to claim 5, characterized in that: The first output gear is concentric with the first extension shaft and the first transmission tooth; The outer diameter of the main gear gradually decreases from close to the first output gear to away from it. The main gear, second extension shaft, and second transmission tooth on the same gear unit are concentric. The second extension shaft is concentric with the corresponding mounting hole on the second support base, so that the center heights of the mounting holes of the second support bases matched with different gear units are different.

8. A speed change system according to claim 2 or 3, characterized in that: A support shaft is arranged on the base, and a plurality of support gears meshing with the main gear of the gear unit are arranged on the support shaft.

9. A speed change system according to claim 8, characterized in that: The base is provided with two sets of support shafts, which are respectively arranged at the front and rear sides of the gear unit; The number of the supporting gears is consistent with the number of the main gears; A first circular inner cavity concentric with the main gear is formed on the side wall thereof, and the first inner tooth portion is arranged on the circular side wall of the first circular inner cavity; A second circular inner cavity concentric with the second output gear is formed on the side wall thereof, and the second inner tooth portion is provided on the circular side wall of the second circular inner cavity; The first transmission teeth are formed on the side wall of the first output gear, and the thickness thereof is adapted to the depth of the corresponding first circular inner cavity to reduce the gap between the first output gear and the adjacent gear unit; The second transmission teeth are formed on the side wall of the main gear, and the thickness thereof is adapted to the depth of the corresponding first circular inner cavity to reduce the gap between two adjacent gear units; The depth of the second circular inner cavity is adapted to the thickness of the corresponding second transmission tooth, so as to reduce the gap between the gear unit and the second output gear.

10. The speed change system according to claim 1, characterized in that: The input gear is located above the first output gear, all the gear units and the second output gear; The upper edges of the first output gear, all the gear units and the second output gear are flush with each other; The base is provided with a connecting shaft, and the first output gear is rotatable relative to the base via the connecting shaft; The horizontal position of the output shaft is higher than the horizontal position of the connecting shaft.

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