A gear shifting mechanism, comprising a gear, a gear hub, a one-way clutch, and a sliding apparatus, wherein the gear comprises a body, a first convex wall and a second convex wall are disposed on an end face of the body, the first convex wall is disposed around a shaft hole of the body, a first toothed structure is disposed at an end of the first convex wall, wherein the end of the first convex wall is away from the body, the second convex wall and the first convex wall are disposed on a same side of the body, the second convex wall is disposed around the shaft hole of the body, a diameter of the second convex wall is less than that of the first convex wall, the gear hub is sleeved on the second convex wall, the one-way clutch is disposed between the gear hub and the second convex wall, an inner ring of the one-way clutch is connected to the second convex wall, and an outer ring of the one-way clutch is connected to the gear hub; the sliding apparatus comprises a supporting frame, a rolling component, and a sliding sleeve, the supporting frame is sleeved on the gear hub, the supporting frame is radially fixed to the gear hub, a second toothed structure is disposed at an end of the supporting frame, wherein the end of the supporting frame faces the first convex wall, the supporting frame is disposed with a mounting slot, the rolling component is mounted in the mounting slot, the rolling component is in contact with a surface of the gear hub, the sliding sleeve is sleeved on the supporting frame, the rolling component is confined between the sliding sleeve and the gear hub, and the sliding sleeve is configured to drive the supporting frame and the rolling component to slide on the surface of the gear hub in a direction toward the gear for meshing the second toothed structure with the first toothed structure or away from the gear for detaching the second toothed structure with the first toothed structure; and wherein the gear shifting mechanism further comprises a rotary shaft, the rotary shaft penetrates the shaft hole of the body, and the gear hub is fixedly connected to the rotary shaft; wherein the gear is sleeved on the rotary shaft by using a bearing; wherein the one-way clutch is configured such that when the second toothed structure is meshed with the first toothed structure, the gear and the rotary shaft rotate synchronously; and when the second toothed structure is detached from the first toothed structure, the gear and the rotary shaft rotate synchronously or differentially. the gear comprises a body, a first convex wall and a second convex wall are disposed on an end face of the body, the first convex wall is disposed around a shaft hole of the body, a first toothed structure is disposed at an end of the first convex wall, wherein the end of the first convex wall is away from the body, the second convex wall and the first convex wall are disposed on a same side of the body, the second convex wall is disposed around the shaft hole of the body, a diameter of the second convex wall is less than that of the first convex wall, the gear hub is sleeved on the second convex wall, the one-way clutch is disposed between the gear hub and the second convex wall, an inner ring of the one-way clutch is connected to the second convex wall, and an outer ring of the one-way clutch is connected to the gear hub; the sliding apparatus comprises a supporting frame, a rolling component, and a sliding sleeve, the supporting frame is sleeved on the gear hub, the supporting frame is radially fixed to the gear hub, a second toothed structure is disposed at an end of the supporting frame, wherein the end of the supporting frame faces the first convex wall, the supporting frame is disposed with a mounting slot, the rolling component is mounted in the mounting slot, the rolling component is in contact with a surface of the gear hub, the sliding sleeve is sleeved on the supporting frame, the rolling component is confined between the sliding sleeve and the gear hub, and the sliding sleeve is configured to drive the supporting frame and the rolling component to slide on the surface of the gear hub in a direction toward the gear for meshing the second toothed structure with the first toothed structure or away from the gear for detaching the second toothed structure with the first toothed structure; and wherein the gear shifting mechanism further comprises a rotary shaft, the rotary shaft penetrates the shaft hole of the body, and the gear hub is fixedly connected to the rotary shaft; wherein the gear is sleeved on the rotary shaft by using a bearing; wherein the one-way clutch is configured such that when the second toothed structure is meshed with the first toothed structure, the gear and the rotary shaft rotate synchronously; and when the second toothed structure is detached from the first toothed structure, the gear and the rotary shaft rotate synchronously or differentially.