CN107524770B

CN107524770B - Speed change mechanism

Info

Publication number: CN107524770B
Application number: CN201710967971.7A
Authority: CN
Inventors: 梁建
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-10-18
Filing date: 2017-10-18
Publication date: 2024-06-21
Anticipated expiration: 2037-10-18
Also published as: CN107524770A

Abstract

The invention discloses a speed change mechanism, which belongs to a gear mechanism comprising two parallel and opposite first shafting, wherein the first shafting comprises a plurality of transmission mechanisms, each transmission mechanism comprises a shaft, a chain wheel is sleeved on each shaft, a first connecting sleeve is arranged between each shaft and each chain wheel, each shaft and each first connecting sleeve are in clearance fit with each chain wheel, and each shaft and each first connecting sleeve are in key connection with each chain wheel; two adjacent transmission mechanisms on the first shafting are connected through a second connecting sleeve, the second connecting sleeve is in clearance fit with the shaft, and the second connecting sleeve is in key connection with the shaft; the chain wheels on the two first shaft systems are respectively connected through a plurality of chains; the invention has reasonable design and convenient manufacture, and can solve the problems of large volume, few gears and high manufacturing precision requirement of the existing speed change mechanism.

Description

Speed change mechanism

Technical Field

The invention relates to the field of transmission equipment, in particular to a speed change mechanism.

Background

The existing parallel shaft gear speed change mechanism has the problems of large volume, small torque and few gear numbers; meanwhile, the existing planetary gear speed change mechanism has the problems of complex structure and high processing precision requirement.

Disclosure of Invention

In order to solve the problems, the invention provides a speed change mechanism.

In order to achieve the above purpose, the invention adopts the following technical scheme: the speed change mechanism comprises two first shaft systems which are parallel to each other and opposite to each other, wherein each first shaft system comprises a plurality of transmission mechanisms, each transmission mechanism comprises a shaft, a sprocket wheel is sleeved on each shaft, a first connecting sleeve is arranged between each shaft and each sprocket wheel, each shaft is in clearance fit with each first connecting sleeve, each first connecting sleeve is in key connection with each sprocket wheel; two adjacent transmission mechanisms on the first shafting are connected through a second connecting sleeve, the second connecting sleeve is in clearance fit with the shaft, and the second connecting sleeve is in key connection with the shaft; the chain wheels on the two first shaft systems are respectively connected through a plurality of chains.

Preferably, the speed change mechanism further comprises a second shaft system and a third shaft system, the second shaft system comprises two transmission mechanisms, the two transmission mechanisms are connected through a second connecting sleeve, the third shaft system comprises two transmission mechanisms, the two transmission mechanisms are connected through a second connecting sleeve, the second shaft system is respectively connected with one ends of the two first shaft systems through two chains, and the third shaft system is respectively connected with the other ends of the two first shaft systems through two chains.

Preferably, the end face of the chain wheel is provided with a ring sleeve, the ring sleeve is coaxial with the chain wheel, and the ring sleeve is in clearance fit with the shaft.

Preferably, the shaft is connected with the first connecting sleeve and/or the shaft is connected with the second connecting sleeve and/or the first connecting sleeve is connected with the chain wheel through a spline.

Preferably, the chain comprises a chain sheet, pins and rollers, a circle of chain teeth is arranged on the side face of the chain wheel, limiting blocks are arranged on the two end faces of the chain wheel in a right-angled mode, a circle of limiting blocks are arranged along the circumferential direction of the chain wheel, the chain sheet is provided with protruding portions, the chain and the chain wheel are meshed, the chain is consistent with the meshing mode of the chain teeth, a plurality of limiting faces are arranged on the two limiting blocks in a right-angled mode, the plurality of limiting faces are evenly distributed along the circumferential direction of the chain wheel, the plurality of limiting faces are arranged adjacently in sequence, the protruding portions are provided with matching faces, the matching faces are right opposite to the limiting faces, and the limiting faces and the matching faces limit the chain to move along the axial direction of the chain wheel.

Preferably, the limiting surface and/or the mating surface is/are inclined, and the limiting surface and/or the mating surface is/are non-parallel and non-perpendicular to the sprocket axis.

Further, the limiting surface is a plane, a plurality of limiting surfaces are arranged on the limiting block in a regular polygon, and the limiting surface inclines back to the axis of the chain wheel.

Preferably, when the number of the limiting surfaces is infinite, the plurality of limiting surfaces form a conical surface, the conical surface is coaxial with the sprocket, and the large end of the conical surface faces outwards or the small end of the conical surface faces outwards, namely, the axial cross sections of the two limiting surfaces are in a V shape or an inverted V shape.

Preferably, when the chain moves in the axial direction of the chain wheel, the matching surface is in point contact with the limiting surface; for example, the protruding portion is spherical or ellipsoidal, at this time, the mating surface is spherical or ellipsoidal, and the two mating surfaces are respectively contacted with the two limiting surfaces, so that the chain is constrained by the limiting block in the axial direction of the chain wheel and cannot swing.

Preferably, when the chain moves in the axial direction of the sprocket, the mating surfaces are in line contact with the limiting surfaces, for example, the protruding portion is conical or trapezoidal or cylindrical, at this time, the mating surfaces are conical or planar or cylindrical, and the two mating surfaces are in contact with the two limiting surfaces, so that the chain is constrained by the limiting blocks in the axial direction of the sprocket, and cannot swing.

Preferably, the mating surface is in surface contact with the limiting surface when the chain moves in the axial direction of the sprocket.

Of course, the limiting surface may be in other shapes, for example, the axial section of the limiting surface is a groove, and the mating surface is a protrusion adapted to the groove; otherwise, the axial section of the limiting surface is a bulge, and the matching surface is a groove which is matched with the bulge in the direction.

Further, the matching surfaces are symmetrically arranged at the upper end and the lower end of the protruding part, and the two matching surfaces are symmetrical relative to the movement direction of the chain piece.

Preferably, when the limiting block is a solid disc, the ring sleeve can be a limiting block, and the limiting block is provided with a through hole in clearance fit with the shaft.

Preferably, the protruding portion is provided inside the chain piece or the protruding portion is provided outside the chain piece.

Preferably, the limiting block is independent of the sprocket.

Further, the limiting block can be arranged on a shaft connected with the chain wheel or arranged at the position of the inclusion part of the chain wheel and the chain or arranged at the position close to the inclusion part of the chain wheel and the chain.

The beneficial effects of the invention are as follows:

1. through the arrangement of the limiting block and the protruding part, the chain cannot swing along the axial direction of the chain wheel on the chain wheel, and the chain can be effectively prevented from sliding off;

2. The limiting block is provided with a circle along the circumference of the chain wheel, and the limiting block and the chain wheel are coaxially arranged, so that the limiting block is convenient to process and manufacture, the chain transmission is stable, and the blocking phenomenon of the limiting block and the protruding part is avoided;

3. the limiting surface is a conical surface, the protruding part is spherical, conical or trapezoidal, and the limiting surface has the advantages of convenient processing and manufacturing and less restriction on the shape of the protruding part;

4. the limiting surface is arranged in a plane perpendicular to the axis of the chain wheel, and the limiting surface is convenient to process and manufacture and has the function of less restriction on the shape of the protruding part;

5. the arrangement of the protruding parts with the symmetrical structures can ensure that the chain can be restrained on two chain wheels when the two sides of the chain are meshed with the chain wheels at the same time;

6. The limiting block and the protruding part are arranged, so that friction between the limiting block and the protruding part is avoided, and friction between the existing chain piece and the side face of the sprocket can be solved;

7. the speed change mechanism adopting chain transmission has the advantages of small volume, multiple gears and large torque.

Drawings

FIG. 1 is a schematic diagram of a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a transmission mechanism;

FIG. 4 is a schematic view of an axle construction;

FIG. 5 is a schematic view of a first coupling sleeve structure;

fig. 6 is a schematic diagram of a second connecting sleeve structure;

FIG. 7 is a schematic view of a collar and sprocket construction;

FIG. 8 is a schematic view of a chain and sprocket of the present invention;

FIG. 9 is a schematic view of a chain configuration;

FIG. 10a is a schematic view of a chain and sprocket configuration with fifteen bit faces;

FIG. 10b is a schematic view of a chain and sprocket with conical surfaces on the limiting surfaces and spherical protrusions;

FIG. 11 is a schematic view of another structure of a chain and a sprocket with a conical limiting surface and spherical protruding parts;

FIG. 12 is a schematic view of a chain and sprocket with conical limiting surfaces and ellipsoidal projections;

FIG. 13 is a schematic view of another structure of a chain and sprocket with a conical limiting surface and an ellipsoidal protruding part;

FIG. 14 is a schematic view of a chain and sprocket with tapered limiting surfaces and tapered protrusions;

FIG. 15 is a schematic view of another structure of a chain and a sprocket with a conical limiting surface and conical protruding parts;

FIG. 16 is a schematic view of a chain and sprocket with tapered limiting surfaces and trapezoidal protrusions;

FIG. 17 is a schematic view of another structure of a chain and a sprocket with a conical limiting surface and trapezoidal protruding parts;

FIG. 18 is a schematic view of a chain and sprocket configuration with grooves on the limit surfaces and protrusions protruding;

FIG. 19 is a schematic view of a chain and sprocket configuration in which the spacer blocks are disc-shaped;

FIG. 20 is a schematic view of a chain, sprocket with symmetrical projections;

FIG. 21 is a schematic view of a chain and sprocket with the projections on the inside of the chain;

FIG. 22 is a schematic view of a chain and sprocket construction with the stop block independent of the sprocket.

In the figure: 1-chain, 11-chain piece, 12-pin, 13-roller, 2-sprocket, 3-stopper, 4-protruding portion, 5-axle, 6-first adapter sleeve, 7-second adapter sleeve, 8-ring cover.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent.

Embodiment one:

As shown in fig. 1, a speed change mechanism comprises two first shafting systems which are parallel and opposite to each other, wherein the first shafting systems comprise a plurality of transmission mechanisms shown in fig. 3, each transmission mechanism comprises a shaft 5 shown in fig. 4, a chain wheel 2 is sleeved on each shaft 5, a first connecting sleeve 6 shown in fig. 5 is arranged between each shaft 5 and each chain wheel 2, each shaft 5 and each first connecting sleeve 6 are in clearance fit, each first connecting sleeve 6 and each chain wheel 2 are in key connection, and each shaft 5 and each first connecting sleeve 6 are in key connection; two adjacent transmission mechanisms on the first shafting are connected through a second connecting sleeve 7 shown in fig. 6, the second connecting sleeve 7 is in clearance fit with the shaft 5, and the second connecting sleeve 7 is in key connection with the shaft 5; the chain wheels 2 on the two first shaft systems are respectively connected through a plurality of chains 1.

As shown in fig. 7, the end face of the sprocket 2 is provided with a ring sleeve 8, the ring sleeve 8 is coaxial with the sprocket 2, and the ring sleeve 8 is in clearance fit with the shaft 5.

The shaft 5 is connected with the first connecting sleeve 6 and/or the shaft 5 is connected with the second connecting sleeve 7 and/or the first connecting sleeve 6 is connected with the chain wheel 2 through a spline.

As shown in fig. 8 and 9, the chain 1 includes a chain piece 11, pins 12 and rollers 13, a circle of sprocket is arranged on the side surface of the chain wheel 2, the chain 1 and the chain wheel 2 are meshed, the chain is consistent with the sprocket in a meshing mode, limiting blocks 3 are arranged on two end surfaces of the chain wheel 2 in a facing manner, the limiting blocks 3 are circumferentially provided with a circle along the chain wheel 2, a plurality of limiting surfaces are arranged on the two limiting blocks 3 in a facing manner, the plurality of limiting surfaces are uniformly distributed along the circumferential direction of the chain wheel 2, the plurality of limiting surfaces are sequentially arranged adjacently, protruding portions 4 are arranged on the outer side of the chain piece 11, the protruding portions 4 are provided with matching surfaces, the matching surfaces are opposite to the limiting surfaces, and the limiting surfaces and the matching surfaces limit the chain 1 to move along the axial direction of the chain wheel 2.

The limiting surface and/or the matching surface are/is inclined surfaces, and the limiting surface and/or the matching surface are not parallel and not perpendicular to the axis of the chain wheel.

The limiting surfaces are all planes, the limiting surfaces are regular polygons and are arranged on the limiting block 3, the limiting surfaces are inclined back to the axis of the chain wheel 2, and fifteen limiting surfaces are arranged in the drawing as shown in fig. 10 a.

The plurality of limiting surfaces form a conical surface, the conical surface is provided with a large end and a small end, and the matching surface and the limiting surfaces can be in point contact or line contact or surface contact.

Specifically, as shown in fig. 10b, when the small end of the limiting surface faces outwards, the protruding portion 4 is spherical, at this time, the mating surfaces are spherical, and the two mating surfaces are in point contact with the two limiting surfaces, so that the chain 1 is constrained by the limiting surfaces located inside the two mating surfaces in the axial direction of the sprocket 2, and cannot swing.

As shown in fig. 11, when the large end of the limiting surface faces outwards, the protruding portion 4 is spherical, at this time, the mating surfaces are spherical, and the two mating surfaces are in point contact with the two limiting surfaces, so that the chain 1 is restrained by the limiting surfaces located outside the two mating surfaces in the axial direction of the sprocket 2, and cannot swing.

As shown in fig. 12, when the small end of the limiting surface faces outwards, the protruding portion 4 is ellipsoidal, at this time, the mating surfaces are ellipsoidal, and the two mating surfaces are in point contact with the two limiting surfaces, so that the chain 1 is constrained by the limiting surfaces located inside the two mating surfaces in the axial direction of the sprocket 2, and cannot swing.

As shown in fig. 13, when the large end of the limiting surface faces outward, the protruding portion 4 is ellipsoidal, and at this time, the mating surfaces are ellipsoidal, and the two mating surfaces are in point contact with the two limiting surfaces, so that the chain 1 is constrained by the limiting surfaces located outside the two mating surfaces in the axial direction of the sprocket 2, and cannot swing.

As shown in fig. 14, when the small end of the limiting surface faces outwards, the protruding portion 4 is tapered, and at this time, the mating surfaces are tapered surfaces, and the two mating surfaces are in contact with the two limiting surface lines, so that the chain 1 is restrained by the limiting surfaces located inside the two mating surfaces in the axial direction of the sprocket 2 and cannot swing.

As shown in fig. 15, when the large end of the limiting surface faces outward, the protruding portion 4 is tapered, and the mating surfaces are tapered, and the two mating surfaces are in contact with the two limiting surface lines, so that the chain 1 is restrained by the limiting surfaces located outside the two mating surfaces in the axial direction of the sprocket 2 and cannot swing.

As shown in fig. 16, when the small end of the limiting surface faces outwards, the protruding portion 4 is trapezoidal, at this time, the mating surface is a trapezoidal inclined surface, and the two mating surfaces are in contact with the two limiting surface lines, so that the chain 1 is restrained by the limiting surface located at the inner side of the two mating surfaces in the axial direction of the sprocket 2, and cannot swing.

As shown in fig. 17, when the large end of the limiting surface faces outward, the protruding portion 4 is trapezoidal, and at this time, the mating surfaces are trapezoidal inclined surfaces, and the two mating surfaces are in contact with the two limiting surface lines, so that the chain 1 is restrained by the limiting surface located outside the two mating surfaces in the axial direction of the sprocket 2 and cannot swing.

Of course, the protruding portion 4 may also be cylindrical, the axis of the cylindrical shape is parallel to the limiting surface, and the mating surface is a cylindrical side surface, and the mating surface contacts with the limiting surface line.

Of course, when the chain 1 moves in the axial direction of the sprocket 2, the mating surface is in surface contact with the limiting surface.

The limiting surface may also be a groove, the opening of the groove faces the direction of the sprocket, and the mating surface is a protrusion adapted to the groove, as shown in fig. 18.

Meanwhile, the limiting block 3 may be a disc, the limiting block 3 is a solid disc, a hole through which the shaft system passes is formed in the middle of the disc, as shown in fig. 19, a schematic structural diagram of the chain 1 and the chain wheel 2 when the limiting block 3 is in a solid disc shape, the limiting surface is a conical surface, and the limiting block is trapezoid is given in the figure, and the different structures of the chain 1 and the chain wheel 2 are suitable for the situation that the limiting block 3 is in a solid disc shape.

As shown in fig. 20, in order to ensure that both sides of the chain 1 are simultaneously meshed with the sprocket 2 and that the movement of the chain 1 in the axial direction of the sprocket 2 does not occur, the upper and lower ends of the protruding portion 4 are symmetrically provided with the mating surfaces, and the two mating surfaces are symmetrical with respect to the movement direction of the chain piece 11; of course, fig. 12 shows only one schematic configuration of the chain 1 and sprocket 2 when the protruding portion 4 is isosceles trapezoid, and the different configurations of the chain 1 and sprocket 2 described above are applicable to the symmetrical configuration of the protruding portion 4.

The protruding portion 4 is disposed inside the chain 11, and the protruding portion 4 is disposed inside the chain 11 as shown in fig. 21, and the chain 1 and the sprocket 2 are shown in schematic structural drawings, and the different structures of the chain 1 and the sprocket 2 described above are applicable to the structure in which the protruding portion 4 is disposed inside the chain 11.

The limiting block 3 is independent of the chain wheel 2 and is used for reducing the volume and the weight of the limiting block 3 when the chain wheel 2 is large in size.

The limiting block 3 can be arranged on a shaft 5 connected with the chain wheel 2

The limiting block 3 is arranged at the position where the chain wheel 2 and the chain 1 are included, as shown in fig. 22, the limiting block 3 is arranged on another shaft which is parallel to the axis of the chain wheel 2, and the limiting block 3 is provided with fifteen limiting surfaces.

The limiting block 3 is arranged at a position close to the inclusion position of the chain wheel 2 and the chain 1.

When the chain is used, the chain 1 is meshed with the chain wheel 2, the transmission mechanism transmits the torque of the shaft 5 through the chain 1, and when the torque needs to be transmitted, the first connecting sleeve 6 is respectively connected with the shaft 5 and the chain wheel 2 by sliding the first connecting sleeve 6, so that the torque of the shaft 5 can be transmitted to the chain 1 through the chain wheel 2; when the transmission torque is not needed, the first connecting sleeve 6 is respectively separated from the shaft 5 and the chain wheel 2 by sliding the first connecting sleeve 6, at the moment, only the annular sleeve 8 is arranged between the shaft 5 and the chain wheel 2, the annular sleeve 8 is in clearance fit with the shaft 5, and the torque of the shaft 5 cannot be transmitted to the chain wheel 2, so that the effect of not transmitting the torque is achieved; simultaneously, the transmission mechanism on the same shaft system can be on and off at different positions through the second connecting sleeves 7 on the two shafts 5 which are adjacent and coaxial in a sliding manner, and meanwhile, the first connecting sleeve 6 between the shaft 5 and the chain wheel 2 on any transmission mechanism can be slid, so that the chain wheel 2 on the transmission mechanism does not transmit torque to the transmission mechanism connected with the chain wheel through the chain 1, different torque transmission routes are achieved, and the transmission mechanism is matched with the chain wheels with different diameter specifications, so that different transmission ratios are realized, and the speed change effect is realized. The protruding portion 4 outside the chain piece 11 is limited by the limiting block 3 on the end face of the chain wheel 2, the chain 1 cannot swing in the axial direction of the chain wheel 2, and the situation that the chain 1 falls off from the axial direction of the chain wheel 2 does not occur.

Embodiment two:

It differs from embodiment one in that: as shown in fig. 2, the speed change mechanism further includes a second shaft system and a third shaft system, the second shaft system includes two transmission mechanisms, the two transmission mechanisms are connected through a second connecting sleeve 7, the third shaft system includes two transmission mechanisms, the two transmission mechanisms are connected through a second connecting sleeve 7, the second shaft system is respectively connected with one ends of the two first shaft systems through two chains 1, and the third shaft system is respectively connected with the other ends of the two first shaft systems through two chains 1.

In this embodiment, the second axis and the third axis are respectively used as a torque input and a torque output, and function in flexibly arranging the input and output shafts.

Of course, the present invention is capable of other various embodiments and its several details are capable of modification and variation in light of the present invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A shift control method characterized by: the novel gear shifting mechanism comprises a gear shifting mechanism, the gear shifting mechanism comprises two first shaft systems which are parallel to each other and opposite to each other, the first shaft systems comprise a plurality of transmission mechanisms, each transmission mechanism comprises a shaft (5), a chain wheel (2) is sleeved on each shaft (5), a first connecting sleeve (6) is arranged between each shaft (5) and each chain wheel (2), each shaft (5) is in clearance fit with each first connecting sleeve (6), each first connecting sleeve (6) is in key connection with each chain wheel (2), each chain wheel (2) is provided with a ring sleeve (8) on the end face, each ring sleeve (8) is coaxial with each chain wheel (2), and each ring sleeve (8) is in clearance fit with each shaft (5); two adjacent transmission mechanisms on the first shafting are connected through a second connecting sleeve (7), the second connecting sleeve (7) is in clearance fit with the shaft (5), and the second connecting sleeve (7) is in key connection with the shaft (5); the chain wheels (2) on the two first shaft systems are respectively connected through a plurality of chains (1);

When the chain is used, the chain (1) is meshed with the chain wheel (2), the transmission mechanism transmits the torque of the shaft (5) through the chain (1), and when the torque needs to be transmitted, the first connecting sleeve (6) is respectively connected with the shaft (5) and the chain wheel (2) by sliding the first connecting sleeve (6), so that the torque of the shaft (5) can be transmitted to the chain (1) through the chain wheel (2); when the transmission torque is not needed, the first connecting sleeve (6) is respectively separated from the shaft (5) and the chain wheel (2) by sliding the first connecting sleeve (6), at the moment, only the annular sleeve (8) is arranged between the shaft (5) and the chain wheel (2), the annular sleeve (8) is in clearance fit with the shaft (5), and the torque of the shaft (5) cannot be transmitted to the chain wheel (2), so that the effect of not transmitting the torque is achieved; the transmission mechanism on the same shaft system is clutched at different positions through the second connecting sleeves (7) on the two shafts (5) which are adjacent and coaxial in a sliding manner, and meanwhile, the first connecting sleeve (6) between the shaft (5) and the chain wheel (2) on any transmission mechanism can be slid, so that the chain wheel (2) on the transmission mechanism does not transmit torque to the transmission mechanism connected with the chain wheel through the chain (1), different torque transmission routes are achieved, and the transmission mechanism is matched with the chain wheels with different diameter specifications through the chain wheels, so that different transmission ratios are achieved, and speed change is achieved.

2. The shift control method according to claim 1, characterized in that: the two transmission mechanisms are connected through a second connecting sleeve (7), the two transmission mechanisms are connected through the second connecting sleeve (7), the second shaft system is connected with one ends of the two first shaft systems through two chains (1), and the third shaft system is connected with the other ends of the two first shaft systems through the two chains (1).

3. The shift control method according to claim 1, characterized in that: the chain (1) comprises a chain sheet (11), pins (12) and rollers (13), a circle of chain teeth is arranged on the side face of the chain wheel (2), limiting blocks (3) are arranged on the two end faces of the chain wheel (2) in a right-angle mode, the limiting blocks (3) are circumferentially arranged in a circle along the chain wheel (2), a plurality of limiting faces are arranged on the two limiting blocks (3) in a right-angle mode and uniformly distributed along the circumference of the chain wheel (2), the plurality of limiting faces are sequentially arranged adjacently, protruding portions (4) are arranged on the chain sheet (11), the protruding portions (4) are provided with matching faces, the matching faces are right-angle to the limiting faces, and the limiting faces and the matching faces limit the chain (1) to move along the axial direction of the chain wheel (2).

4. The shift control method according to claim 3, characterized in that: the limiting surface and/or the matching surface are/is inclined surfaces, and the limiting surface and/or the matching surface are not parallel and are not perpendicular to the axis of the chain wheel (2).

5. The shift control method according to claim 3, characterized in that: the limiting surfaces form conical surfaces, the limiting surfaces are provided with a circle along the circumferential direction of the chain wheel (2), and the conical surfaces are coaxial with the chain wheel (2).

6. The shift control method according to claim 5, characterized in that: the matching surface is in point contact or line contact with the limiting surface.

7. The shift control method according to claim 4, characterized in that: the matching surface is in surface contact with the limiting surface.

8. The shift control method according to claim 5, characterized in that: the limiting surface is a groove or a bulge, and the matching surface is a bulge or a groove matched with the groove or the bulge.

9. The shift control method according to claim 4, characterized in that: the limiting surface is a plane, and the limiting surface is inclined back to the axis of the chain wheel (2).

10. The shift control method according to any one of claims 3 to 9, characterized in that: the upper end and the lower end of the protruding part (4) are symmetrically provided with the matching surfaces, and the two matching surfaces are symmetrical relative to the movement direction of the chain piece (11).