A speed change mechanism and a vehicle that achieve automatic gear shifting by using the output speed

Abstract

The present invention discloses a speed change mechanism and a vehicle that achieve automatic gear shifting by using the output speed, which relates to the field of speed change devices. The key points of its technical solution include a power output unit; a power input unit, the power input unit includes a first input member and a second input member, and the rotational speed of the second input member is higher than that of the first input member; a second clutch assembly; a centrifugal drive assembly for controlling the second clutch assembly is provided on the power output unit; when the rotational speed of the power output unit is lower than the set value, the centrifugal drive assembly restricts the second clutch assembly, so that the rotational speed of the second input member cannot be transmitted to the power output unit through the second clutch assembly; after the rotational speed of the power output unit reaches the set value, the centrifugal drive assembly releases the second clutch assembly, so that the rotational speed of the second input member is transmitted to the power output unit through the second clutch assembly. The present invention uses the output speed to achieve automatic gear shifting, which can improve the riding experience, reduce the gear shifting frequency, and extend the service life.

Description

Technical Field

[0001] The present invention relates to the field of speed change devices, and more particularly, to a speed change mechanism and a vehicle that use the output speed to achieve automatic shifting. Background Art

[0002] Generally, an internal speed change mechanism uses centrifugal force to achieve automatic speed change. When a certain pedaling frequency speed is reached, the centrifugal blocks are thrown away to achieve automatic upshifting. When the pedaling frequency speed drops below the speed change point, the centrifugal blocks will contract to achieve automatic downshifting, as shown in the Chinese patent with the authorization announcement number CN208882034U.

[0003] However, for a vehicle using the above speed change mechanism, when the vehicle is traveling at a high speed (greater than the speed change point), if the rider does not want to pedal, or does not need to pedal during downhill, the speed change mechanism will automatically downshift due to the decrease in the rider's pedaling frequency speed; when the vehicle remains at a high speed (greater than the speed change point) after coasting for a certain distance, when the rider pedals again, it is necessary to reach the speed change point within a short time to make the speed change mechanism automatically upshift. In this case, the automatic downshifting of the speed change mechanism will affect the riding experience, and the increase in the shifting frequency is likely to cause failures of the speed change mechanism and affect its service life. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, one of the purposes of the present invention is to provide a speed change mechanism that uses the output speed to achieve automatic shifting, which uses the output speed to achieve automatic shifting, can improve the riding experience, reduce the shifting frequency, and extend the service life.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A speed change mechanism that uses the output speed to achieve automatic shifting, comprising:

[0007] A power output unit;

[0008] A power input unit, the power input unit includes a first input member and a second input member, and the rotational speed of the second input member is higher than that of the first input member;

[0009] A first clutch assembly carried between the first input member and the power output unit;

[0010] A second clutch assembly carried between the second input member and the power output unit;

[0011] A centrifugal drive assembly for controlling the second clutch assembly is provided on the power output unit;

[0012] Among them, when the rotation speed of the power output unit is lower than the set value, the centrifugal drive assembly limits the second clutch assembly so that the rotation speed of the second input member cannot be transmitted to the power output unit through the second clutch assembly; after the rotation speed of the power output unit reaches the set value, the centrifugal drive assembly releases the second clutch assembly so that the rotation speed of the second input member is transmitted to the power output unit through the second clutch assembly.

[0013] Furthermore, the power input unit includes a set of planetary gear assemblies, or a plurality of sets of planetary gear assemblies connected for transmission.

[0014] By using a set of planetary gear assemblies, the shifting between two gears can be achieved, and by providing multiple sets of connected transmission planetary gear assemblies, the number of gears of the speed change mechanism can be increased.

[0015] Furthermore, the second clutch assembly includes a pawl and a ratchet; the centrifugal drive assembly includes a centrifugal block and a limit plate, the centrifugal block is provided with a shaft connected to the power output unit, and the limit plate is provided with a release groove that cooperates with the pawl; the centrifugal block can drive the limit plate to rotate, so that the pawl is embedded in the release groove and engages with the ratchet.

[0016] Furthermore, the centrifugal block is provided with a swing arm, the swing arm is provided with a driving rod, and the limiting plate is provided with a driving hole that cooperates with the driving rod.

[0017] Furthermore, the centrifugal block and the swing arm are connected via a pin, and the positions of the pin relative to the centrifugal block and the swing arm along the circumferential direction are fixed.

[0018] Furthermore, the centrifugal drive assembly includes a plurality of centrifugal blocks uniformly distributed along the circumferential direction, and only one of the centrifugal blocks is provided with an elastic reset member connected to the power output unit.

[0019] Taking into account the influence of raw materials and processing technology, there will inevitably be differences even between elastic return parts of the same specifications. If multiple elastic return parts are used, it may affect the resetting of the limit plate. However, setting only one elastic return part can avoid the above problem and ensure the smooth resetting of the limit plate.

[0020] Furthermore, the power output unit includes a housing and a positioning plate fixedly connected to the housing; the second clutch assembly also includes a pawl seat fixedly connected to the positioning plate.

[0021] Furthermore, two ends of the shaft rod are respectively connected to the housing and the positioning plate.

[0022] Furthermore, the centrifugal block is radially arranged outside the second clutch assembly.

[0023] By adopting the above solution, the centrifugal blocks are arranged radially outside the second clutch assembly, which can reduce the axial dimension of the speed change mechanism.

[0024] Another object of the present invention is to provide a vehicle, which includes the above speed change mechanism.

[0025] The above speed change mechanism can be applied to bicycles, electric assist bicycles or other vehicles that require speed change.

[0026] In summary, the present invention has the following beneficial effects:

[0027] 1. Using the output speed to achieve automatic shifting can improve the riding experience, reduce the shifting frequency, and extend the service life;

[0028] 2. Only one elastic reset member is used for multiple centrifugal blocks, which can ensure the smooth reset of the limit plate. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the overall structure of the speed change mechanism for realizing automatic shifting by using the output speed in Embodiment 1;

[0030] Figure 2 It is a cross-sectional view of the speed change mechanism for realizing automatic shifting by using the output speed in Embodiment 1;

[0031] Figure 3 It is a schematic diagram of the structure of the centrifugal drive assembly in Embodiment 1;

[0032] Figure 4 It is a schematic diagram of the structure of the ratchet wheel and the gear ring in Embodiment 1.

[0033] In the figure: 1, main shaft; 2, housing; 31, planet carrier; 311, tooth piece; 32, planet gear; 33, sun gear; 34, gear ring; 341, second protrusion; 4, first clutch assembly; 51, ratchet pawl seat; 52, ratchet pawl; 53, ratchet wheel; 531, first protrusion; 6, positioning plate; 61, relief sink; 71, centrifugal block; 72, shaft rod; 73, torsion spring; 74, stud; 75, swing arm; 751, drive rod; 76, limit plate; 761, release groove; 762, drive hole; 81, first bearing; 82, second bearing; 83, third bearing. Detailed Description of the Invention

[0034] The present invention will be further described in detail below with reference to the accompanying drawings.

[0035] This specific embodiment is only an interpretation of the present invention and does not limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.

[0036] Embodiment:

[0037] A speed-changing mechanism that realizes automatic gear shifting by using the output speed. Refer to Figure 1 and Figure 2 , which includes a power output unit and a power input unit; the power input unit includes a first input member and a second input member, and the rotational speed of the second input member is higher than that of the first input member; a first clutch assembly is arranged between the first input member and the power output unit, a second clutch assembly is arranged between the second input member and the power output unit, and a centrifugal drive assembly for controlling the second clutch assembly is arranged on the power output unit; wherein, when the rotational speed of the power output unit is lower than the set value, the centrifugal drive assembly restricts the second clutch assembly, so that the rotational speed of the second input member cannot be transmitted to the power output unit through the second clutch assembly. At this time, the rotational speed of the first input member is transmitted to the power output unit through the first clutch assembly; after the rotational speed of the power output unit reaches the set value, the centrifugal drive assembly releases the second clutch assembly, so that the rotational speed of the second input member is transmitted to the power output unit through the second clutch assembly. At this time, the rotational speed of the power output unit is greater than that of the first input member, making the first clutch assembly in an overrunning state.

[0038] Refer to Figure 1 and Figure 2 , specifically, in this embodiment, the power input unit includes a main shaft 1 and a planetary gear assembly sleeved on the main shaft 1; the first input member is the planet carrier 31 in the planetary gear assembly, the second input member is the ring gear 34 in the planetary gear assembly, a sun gear 33 is fixedly arranged on the main shaft 1, and planet gears 32 are arranged on the planet carrier 31; a toothed plate 311 is arranged on the planet carrier 31, and the toothed plate 311 is used for inputting rotational speed. Then, the toothed plate 311 drives the planet carrier 31 to rotate, the sun gear 33 remains stationary, and the ring gear 34 is driven to rotate through the planet gears 32. Therefore, the rotational speed of the ring gear 34 is greater than that of the planet carrier 31; in this embodiment, a set of planetary gear assemblies can realize the transformation of two gears. If more gear transformations are to be realized, a connection and transmission method using multiple sets of planetary gear assemblies can be adopted to achieve it; of course, in other alternative embodiments, the planetary gear assembly can also be replaced by other structures, which is not limited here.

[0039] Refer to Figure 1 and Figure 2, in this embodiment, the power output unit includes a housing 2, a second bearing 82 is provided between the planet carrier 31 and the housing 2, a third bearing 83 is provided between the ring gear 34 and the housing 2, and two first bearings 81 are provided between the main shaft 1 and the planet carrier 31; in this embodiment, the first clutch assembly 4 is a ratchet and pawl assembly, and the planet carrier 31 can drive the housing 2 to rotate through the ratchet and pawl assembly. When the rotational speed of the housing 2 is greater than that of the planet carrier 31, the ratchet and pawl assembly is in an overrunning state; of course, in other alternative embodiments, the first clutch assembly 4 can also be replaced by other overrunning clutches such as one-way bearings, which is not limited herein.

[0040] Referring to Figures 1 to 4 , in this embodiment, the second clutch assembly is also a ratchet and pawl assembly, which specifically includes a pawl seat 51, a pawl 52, a spring ring, and a ratchet 53; the housing 2 is fixedly connected with a positioning plate 6, and the pawl seat 51 is fixedly connected to the end face of the positioning plate 6; the ratchet 53 and the ring gear 34 can be circumferentially linked. When the second clutch assembly is in the engaged state, the ring gear 34 can drive the housing 2 to rotate through the second clutch assembly and the positioning plate 6; in this embodiment, the positioning plate 6 cooperates with the housing 2 to form a cavity inside for accommodating each component; in other alternative embodiments, the second clutch assembly can also be replaced by other clutch structures, which is not limited herein.

[0041] Referring to Figure 2 and Figure 3 , the centrifugal drive assembly includes a centrifugal block 71 and a limiting plate 76. A shaft rod 72 connected to the power output unit is penetrated through the centrifugal block 71, and a release groove 761 cooperating with the pawl 52 is formed on the limiting plate 76; when the centrifugal block 71 is in the contracted state, the inner side wall of the limiting plate 76 contacts the pawl 52, so that the engaging end of the pawl 52 cannot bounce up to engage with the ratchet 53, and thus the second clutch assembly cannot achieve transmission under the limiting action of the centrifugal drive assembly; after the centrifugal block 71 swings out, it drives the limiting plate 76 to rotate, making the release groove 761 opposite to the pawl 52. Then, the engaging end of the pawl 52 bounces up and is embedded in the release groove 761 and engages with the ratchet 53, and the second clutch assembly can achieve transmission after being released by the centrifugal drive assembly.

[0042] Referring to Figure 2 and Figure 3, in this embodiment, the centrifugal blocks 71 are arranged radially outside the second clutch assembly, so as to reduce the axial dimension; specifically, one end of the shaft rod 72 is embedded in the inner end wall of the housing 2, and the other end is embedded in the positioning plate 6; a swing arm 75 is arranged on the centrifugal block 71, a driving rod 751 is arranged on the swing arm 75, a driving hole 762 matching with the driving rod 751 is formed on the limiting plate 76, and the driving hole 762 is an oblong hole; a relief counterbore 61 matching with the swing arm 75 is formed on the positioning plate 6, so as to reduce the axial dimension; the centrifugal block 71 and the swing arm 75 are connected by a pin 74, and the positions of the pin 74 relative to the centrifugal block 71 and the swing arm 75 in the circumferential direction are both fixed and unchanged, then the centrifugal block 71 can drive the swing arm 75 to deflect through the pin 74; after the swing arm 75 deflects, the driving rod 751 contacts the inner wall of the driving hole 762, driving the limiting plate 76 to rotate.

[0043] Referring to Figure 2 and Figure 3 , the centrifugal drive assembly includes a plurality of centrifugal blocks 71 evenly distributed in the circumferential direction, and an elastic resetting member connected to the power output unit is arranged on only one of the centrifugal blocks 71; in this embodiment, the number of the centrifugal blocks 71 is two, and the elastic resetting member is a torsion spring 73; the torsion spring 73 is sleeved on the shaft rod 72, one end of which is connected to the centrifugal block 71, and the other end is embedded in the positioning plate 6; the elastic force of the torsion spring 73 can reset the centrifugal block 71 to the contracted state, and only setting one torsion spring 73 can ensure the smooth resetting of the limiting plate 76; in this embodiment, the inner side wall of the housing 2 plays a radial limiting role on the centrifugal block 71. In other alternative embodiments, a separate ring plate can also be provided to radially limit the centrifugal block 71, which is not limited here.

[0044] Referring to Figure 2 and Figure 4 , in this embodiment, the gear ring 34 includes two inner circumferential side walls with different inner diameters, an internal tooth matching with the planet gear 32 is arranged on one of the inner circumferential side walls, and a plurality of second protrusions 341 are evenly arranged on the other inner circumferential side wall; a plurality of first protrusions 531 are evenly arranged on the outer circumferential side wall of the ratchet wheel 53, and the contact between the first protrusions 531 and the second protrusions 341 can realize the circumferential linkage between the ratchet wheel 53 and the gear ring 34, and the linkage between the ratchet wheel 53 and the gear ring 34 through the first protrusions 531 and the second protrusions 341 can provide buffering during gear shifting and improve the riding experience.

[0045] The working principle is as follows:

[0046] The rotational speed of the pedal power is transmitted to the tooth piece 311, the tooth piece 311 drives the planet carrier 31 to rotate, the sun gear 33 is fixed, the planet carrier 31 drives the gear ring 34 to rotate through the planet gear 32, and the rotational speed of the gear ring 34 is greater than that of the planet carrier 31.

[0047] When in low gear: The centrifugal block 71 is in a contracted state, and the pawl 52 in the second clutch assembly cannot be engaged with the ratchet wheel 53 under the restriction of the limit plate 76, so the rotation speed of the gear ring 34 cannot be transmitted to the housing 2 through the second clutch assembly; at this time, the planet carrier 31 drives the housing 2 to rotate through the first clutch assembly 4 to achieve power output.

[0048] When in high gear: After the rotation speed of the housing 2 reaches the shift point, the centrifugal block 71 rotates to the thrown-open state under the action of centrifugal force, and drives the limit plate 76 to rotate through the swing arm 75, so that the pawl 52 in the second clutch assembly is opposite to the release groove 761; after the engaging end of the pawl 52 bounces up and is embedded in the release groove 761 and engages with the ratchet wheel 53, the second clutch assembly can realize transmission at this time, and the rotation speed of the gear ring 34 is transmitted to the housing 2 through the second clutch assembly to achieve power output; at this time, the rotation speed of the housing 2 is greater than the rotation speed of the planet carrier 31, and the first clutch assembly 4 is in an overrunning state.

[0049] Using the housing 2 as the power output unit to control the centrifugal drive assembly, if the rotation speed of the housing 2 is greater than the shift point, and the rider does not want to pedal, or does not need to pedal during downhill, the transmission mechanism will still remain in the high gear state. When the rider pedals again, there is no need to change the pedaling frequency to shift gears, thus improving the riding experience. Moreover, the gear position of the transmission mechanism will not change during this process, which can reduce the shifting frequency and extend the service life of the transmission mechanism.

[0050] Embodiment 2:

[0051] A vehicle, which includes the transmission mechanism in Embodiment 1.

[0052] The vehicle in this embodiment can be a bicycle, an electric assist bicycle or other vehicles that require shifting.

Claims

1. A speed change mechanism that realizes automatic gear shifting by using the output speed, comprising: A power output unit; A power input unit, the power input unit includes a first input member and a second input member, and the rotational speed of the second input member is higher than that of the first input member; A first clutch assembly carried between the first input member and the power output unit; A second clutch assembly carried between the second input member and the power output unit; It is characterized in that: A centrifugal drive assembly for controlling the second clutch assembly is provided on the power output unit; Wherein, when the rotational speed of the power output unit is lower than the set value, the centrifugal drive assembly restricts the second clutch assembly, so that the rotational speed of the second input member cannot be transmitted to the power output unit through the second clutch assembly; after the rotational speed of the power output unit reaches the set value, the centrifugal drive assembly releases the second clutch assembly, so that the rotational speed of the second input member is transmitted to the power output unit through the second clutch assembly; The power input unit includes a main shaft and a planetary gear assembly sleeved on the main shaft; the first input member is the planet carrier in the planetary gear assembly, the second input member is the gear ring in the planetary gear assembly, a sun gear is fixedly arranged on the main shaft, and planet gears are arranged on the planet carrier; The power output unit includes a housing and a positioning plate fixedly connected to the housing; The second clutch assembly is a ratchet and pawl assembly, including a pawl seat, a pawl, a spring ring and a ratchet; the pawl seat is fixedly connected to the positioning plate, and the ratchet and the gear ring can be circumferentially linked; The centrifugal drive assembly includes a centrifugal block, a shaft rod and an elastic reset member; both ends of the shaft rod are respectively connected to the housing and the positioning plate; the elastic reset member is a torsion spring, the torsion spring is sleeved on the shaft rod, one end of which is connected to the centrifugal block, and the other end is embedded in the positioning plate; The centrifugal block is arranged radially outside the second clutch assembly.

2. The speed change mechanism for automatic gear shifting using the output speed according to claim 1, wherein: The power input unit includes a set of planetary gear assemblies, or multiple sets of connected and transmitted planetary gear assemblies.

3. The speed change mechanism for automatically shifting gears by using the output speed according to claim 1, wherein: The centrifugal drive assembly further includes a limit plate, and a release groove for cooperating with the pawl is provided on the limit plate; the centrifugal block can drive the limit plate to rotate, so that the pawl is embedded in the release groove and meshes with the ratchet.

4. The speed change mechanism for automatic gear shifting using the output speed according to claim 3, characterized in that: A swing arm is arranged on the centrifugal block, a driving rod is arranged on the swing arm, and a driving hole for cooperating with the driving rod is provided on the limit plate.

5. The speed change mechanism for automatic gear shifting using the output speed according to claim 4, characterized in that: The centrifugal block and the swing arm are connected by a pin, and the position of the pin relative to the centrifugal block and the swing arm in the circumferential direction is fixed and unchanged.

6. The speed change mechanism for automatic gear shifting using the output speed according to claim 3, wherein: The centrifugal drive assembly includes a plurality of centrifugal blocks evenly distributed in the circumferential direction, and only one of the centrifugal blocks is provided with an elastic reset member connected to the power output unit.

7. A vehicle, characterized in that: Including the speed change mechanism according to any one of claims 1-6.

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