TWI858181B - Larger and smaller chain wheels of a multiple chain wheel arrangement - Google Patents

Abstract

The invention relates to improved embodiments of shift channels on multiple arrangements of chain wheels for mounting on a bicycle rear wheel hub. In particular, the previously existing drawbacks, which in connection with known shift channels may lead to faulty gear shifting and the chain dropping out, are remedied.

Description

Larger sprocket and smaller sprocket in a multi-sprocket configuration

The concept of roller chains switching between sprockets of a multi-sprocket arrangement for gear changes is well known. In order to ensure that the chain shifting is smooth, seamless and stable, recesses are provided on the sprockets as components of shifting channels, which provide space for the chain plates of the roller chain. The shifting channels are arranged at specific circumferential positions so that a roller chain that leaves a sprocket can also smoothly reengage on the sprocket to which the roller chain has switched.

It is a shifting channel used to shift the roller chain from a smaller starting sprocket to a larger target sprocket in inward shifting, and from a larger starting sprocket to a smaller target sprocket in outward shifting.

Based on how the segments of the roller chain successively contact or engage with the teeth on one of the sprockets that follow in the opposite direction to the driving rotation direction, how they engage with the teeth on the target sprocket in the inward shift and how they engage with the teeth on the starting sprocket in the outward shift, the inward shift path can be particularly clearly distinguished from the outward shift path.

The inner edge of the notch of the shift channel has a spiral orientation and corresponds to the switching direction.

In most cases, the recess begins already on the radial outer tooth profile, corresponding to the deflection movement of the section of the chain link extending between adjacent sprockets during the switching operation.

For the inward shifting channel used to shift the chain from the adjacent smaller sprocket to the larger sprocket, a spiral directed radially outward is provided opposite to the driving rotation direction. The lead-in side of the inward shifting channel is located radially inwardly and the lead-out side of the inward shifting channel is located radially outwardly. The inward shifting channel can also be regarded as and referred to as an ascending shifting channel.

For the outward displacement channel used to shift the chain from the adjacent larger sprocket to the smaller sprocket, a spiral directed radially inward is provided opposite to the driving rotation direction. The lead-in side of the inward displacement channel is located radially outside, and the lead-out side of the outward displacement channel is located radially inside. The inward displacement channel can also be regarded as and called a descending displacement channel.

The position of the displacement channel in the circumferential direction is based on the fact that the roller chain links also have to reengage well on the teeth on the target pinion, i.e. the teeth can fit well into the intermediate cavity between a pair of inner or outer chain links. This corresponds to the phase conditions to be observed, i.e. the phase relationship between adjacent sprockets in which the chain displacement should take place. For a straight line extension from the starting sprocket to the target sprocket, the phase condition should correspond to a distance condition according to which the distance between the geometric axis of the last chain pin still in the tooth gap of the chain link on the starting sprocket and the geometric axis of the first chain pin of the chain link caught between two teeth on the target sprocket should be approximately an integer multiple of the chain pitch.

If the radial position of the chain pin mentioned is changed radially inwards or radially outwards by a corresponding construction of the teeth on the sprocket, the phase relationship can be changed, for example, as disclosed in patent DE 10 2015 219 522 A1 (applicant's internal file number 20206).

Another way to change the phase condition is to change the straight extension of the chain to an arc extension.

The sprocket disclosed in DE 102012023819 has an even number of teeth and coarse teeth and fine teeth alternating along the circumference. The concepts of "coarse" and "fine" are relative to the dimensions in the direction parallel to the rotation axis of the sprocket.

In addition to the necessary even number of teeth, the coarse teeth on the sprocket must be synchronized with the outer chain link, and the fine teeth on the sprocket must be synchronized with the inner chain link. Therefore, the term "XSync" is also used for this type of sprocket.

Synchronism must be maintained even after the switching process and between the teeth on the target sprocket and the roller chain.

For example, EP 0313345 discloses a shifting channel for inward switching for switching to an adjacent larger chain wheel. Based on the ratio of the number of teeth and the ratio of the diameter of the adjacent chain wheels, the recess extends to the tooth tip. This is due to the fact that the outer contour of the chain plate in its end position in the shifting channel projects radially outwards beyond the outer contour of the tooth.

Two situations are distinguished regarding how the outer chain plate is positioned relative to the first engagement tooth.

In one case, the outer link plate is positioned near the first engagement tooth on the outward side, and the first engagement tooth enters the middle cavity of a pair of outer link plates of the roller chain. The first engagement tooth has an engagement chamfer on the inward side, wherein the tooth tip of the first engagement tooth is offset to the outward side.

In the opposite case, the inner link of the roller chain is positioned near the first engagement tooth on the outward side and passes through this first engagement tooth on the outward side. After this first link has passed, the next outer link link of the roller chain engages with the second engagement tooth that follows in the opposite direction of rotation of the sprocket, wherein this second engagement tooth enters the middle cavity of a pair of outer links.

In certain embodiments of the displacement channel, the convex end piece of the outer chain plate of the chain, which is located in front opposite to the driving rotation direction, already comes into contact with the unloaded tooth flank on the first engaging tooth before the inner chain plate passes through. In combination with this contact, a lifting of the outer chain plate can be achieved, wherein the outer chain plate is lifted to a position with a larger radius. This contact can be achieved because, for the outer chain plate, the recess provides space for the inward displacement of the outer chain plate on the spatially predetermined tooth following the first engaging tooth in the driving rotation direction.

EP 0642972 discloses a shift channel for outward switching, which is used for switching to an adjacent smaller chain wheel, wherein a chamfer inclined relative to the circumferential direction is used. A passage tooth for the inner chain plate link to pass outward is provided on the outward side of the larger chain wheel, and a shift channel extends radially inward from the passage tooth.

If the difference in the number of teeth between the starting sprocket and the target sprocket is greater, the recess used in this case has a greater longitudinal extension along the helix. In this case, the entire outer chain plate or even a partial section of an adjacent outer chain plate is accommodated in the recess when viewed in a direction parallel to the axis of rotation.

EP 3009339 discloses such a notch.

Besides the desired effect of providing space for the chain plates of the roller chain during the shifting process to the adjacent sprocket, the notch in the shift channel also has an unexpected effect.

The notches as an essential component of the displacement channel reduce the cross-section on the teeth, which necessarily leads to a reduction in the load that can be transmitted via these cross-sections. In addition, the contact surface on the loaded flanks of the teeth between the rollers of the roller chain and on the teeth of the sprocket is reduced, so the pressure per unit area increases, which has an adverse effect on the wear characteristics.

The inward shifting channel has space-giving teeth as an integral component to provide space for the chain.

In certain cases, the space provided can have a negative effect. Negative effects can occur both during the rotational movement of the sprocket in the drive rotational direction and during the rotational movement of the sprocket opposite to the drive rotational direction.

During rotational movement opposite to the drive rotational direction, the chain may come off which needs to be prevented.

During the rotational movement in the drive rotational direction, an undesired outward displacement of the roller chain can occur at positions where the phase conditions/distance conditions to be observed with regard to the chain displacement of the roller chain are not met and problems arise.

In the outward displacement channel, undesired roller chain displacement can also occur during the inward displacement of the roller chain, where the phase conditions/distance conditions are not met and problems arise.

The prior art has disclosed a solution to this problem as shown in FIG3 , but this solution still has the problem of low strength and a problem of higher unit area pressure on the smaller surface where the roller of the roller chain contacts the loaded tooth flank of the pinion gear.

On an Xsync sprocket, the roller chain links need to be synchronized with the coarse and fine teeth.

On the one hand, this creates limitations, but on the other hand it opens up some possibilities for the design of sprockets using XSync.

For example, when switching inwards to an XSync sprocket, it is not necessary to switch by raising the outer chain plate and then passing the inner chain plate. On the other hand, the depth of the outward recess of the spatially given tooth can be reduced. EP 3009339 discloses such a construction scheme.

EP 3009339 has proposed that: on the inward displacement channel, the depth of the recess extending to the tooth tip on the space-given tooth is only sufficient to accommodate the section of the inner link plate that is positioned next to the space-given tooth on the outward side. There is not enough space to accommodate the outer link plate of the roller chain. Therefore, the tooth tip of the space-given tooth is thicker in the axial direction, and there is still enough space on the tooth tip of the space-given tooth along the axial direction to form an inward centering chamfer. This centering chamfer is used to achieve reliable engagement of the space-given tooth in the middle cavity between a pair of inner link plates of the chain, thereby preventing the entire inner link plate link from passing through this space-given tooth outwardly in the case of reverse pedaling. Otherwise, passing the given tooth outwards will cause the chain to jump off the sprocket during reverse pedalling.

However, practice has shown that the axial extension of the chamfer is not sufficient to prevent the chain from jumping in all cases.

The solution of the present invention to this problem is that the recess does not extend to the tooth tip, but a protrusion is provided in the recess, which extends approximately to the level of the original material plane, that is, the level of the flat surface on the outward side of the sprocket.

In this embodiment of the invention, the larger and smaller of the adjacent sprockets have an even number of teeth, and the coarse teeth and the fine teeth alternate along the circumference, as disclosed in DE 102012023819. However, the concept of the invention is not limited to this.

It is also possible to adopt the larger target sprocket as an XSync sprocket, but the adjacent smaller sprocket is not an XSync sprocket solution. Therefore, even in the specific case where there are outer chain plate links adjacent to the protrusions on the teeth, the protrusions in the recess can be used to support the outer chain plate radially and achieve synchronization of the chain with the teeth on the larger sprocket.

The concept of the present invention can also be applied to a chain wheel without coarse and fine teeth. In this case, during the inward switching process, the switching achieved through the inner chain plate passage on the first sharp tooth is deliberately abandoned by adopting a corresponding tooth design. In this way, one of the two switching schemes is abandoned. On the other hand, it has advantages in preventing the chain from falling off during reverse pedaling and preventing accidental outward switching.

1:Multiple sprocket configuration

2: Sprocket

3: Larger sprocket

4: Smaller sprocket

5: Inward

6: Outward

7: Flat surface

8: Starting sprocket

9: Target sprocket

10: Shift channel

11: Introduction side

12: Lead-out side

13: Notch

14: protrusion; bulge

14a: Contact surface

15: Inward shift channel

16: Outward shift channel

17: Push and chamfer

18: Splice

19: Bridge Department

20: Roller chain

21: outer chain link; link; segment

22: Inner chain link; link; segment

23: External chain plate pair

24: Inner chain plate pair

25: Chain roller

26: Chain pin

27: Outer chain plate

28: Inner chain plate

29: Inner surface

30: Teeth

31: Loading the Teeth and Belly

32: Non-loaded abdomen

33: Tooth tip

36: Coarse teeth

37: Thin teeth

38: Tooth root

40: First engagement tooth; first switching tooth

41: Second engagement tooth; second switching tooth

42: Chamfering

43: Space given teeth

44: Centering chamfer

45: Access teeth

D: Drive rotation direction

The present invention is now described in conjunction with an embodiment.

Figure 1: A bicycle in which the multi-pinion configuration of the present invention can be applied

Figure 2: Roller chain for bicycles

Figure 3: Shift channel in prior art

Figure 4: A view of the multi-sprocket configuration of the present invention viewed from the outside

Figure 5: A partial view of the multi-sprocket configuration in Figure 1 showing the two shifting channels in better detail

Figure 6: A view of the multi-sprocket configuration of the present invention viewed from the inside

Figure 7: A partial view of the multi-sprocket configuration in Figure 3, showing the tooth design in better detail

Figure 8: A perspective view of the multi-sprocket configuration of the present invention as shown in Figure 2, viewed obliquely along the driving rotation direction D Figure

Figure 9: Perspective view of the detail in Figure 3, viewed obliquely along the driving rotation direction D

Figure 10: A perspective view of the multi-sprocket configuration of the present invention as shown in Figure 4, viewed from an angle opposite to the driving rotation direction D

Figure 11: Perspective view of the detail in Figure 5, viewed from an angle opposite to the driving rotation direction D

Figure 12: A perspective view of the multi-sprocket configuration (1) of the present invention as shown in Figure 6, viewed from an angle opposite to the driving rotation direction D

Figure 13: Perspective view of the detail in Figure 12, viewed from an angle opposite to the driving rotation direction D

Figure 14: A partial view of the sprocket (3) of an alternative embodiment including an outward displacement channel (16) viewed from the outside

Figure 15: A perspective view of the multi-sprocket configuration (1) of the present invention as shown in Figure 14, viewed obliquely along the driving rotation direction D

Figure 16: A perspective view of the multi-sprocket configuration of the present invention as shown in Figure 14, viewed from an angle opposite to the driving rotation direction D

FIG. 1 shows a mountain bike including a chain-type derailleur, a rear multiple sprocket arrangement on the rear wheel, and a single front sprocket.

FIG. 2 shows a roller chain (20) conventional for bicycles, having an outer chain link (21) including an outer chain pair (23), an inner chain link (22) including an inner chain pair (24), a chain roller (25) and a chain pin (26), and adapted to work with the multi-sprocket arrangement of the present invention.

The multi-sprocket arrangement (1) according to FIG. 4 rotates in the driving rotation direction D under driving conditions, wherein the segments (21, 22) of the roller chain (20) not shown successively engage with the teeth (30) on one of the sprockets (3, 4) which are consecutive and opposite to the driving rotation direction D.

On the larger of the sprockets (3, 4) several notches (13) of the shift channel (10) can be seen, which provide space for the roller chain (20) which switches from one of the sprockets (3, 4) to the adjacent sprocket. The inner edge of the notch (13) has a spiral orientation, corresponding to the switching direction. For the shift channel for shifting the chain from the adjacent smaller sprocket (4) inwardly to the larger sprocket (3), an outwardly oriented spiral is provided opposite to the drive rotation direction D. As for the displacement channel (10) for displacing the roller chain (20) outward from the adjacent larger sprocket (3) to the smaller sprocket (4), an inwardly directed spiral is provided opposite to the driving rotation direction D.

In a preferred embodiment of the present invention, a larger sprocket (3) comprising 52 teeth (30) and a smaller sprocket (4) comprising 42 teeth (30) are provided. The difference in the number of teeth is 10, wherein the number of teeth 42 and 52 cannot be divided by 10 without remainder. This results in that the total of 5 inward displacement channels (15) and 5 outward displacement channels (16) clearly shown in FIG. 4 are similar, but cannot adopt the same construction scheme. Each displacement channel (10) adopts a different construction scheme.

The left side of FIG. 5 shows an outward displacement channel (16) for the outward displacement of the roller chain (20), and the right side of FIG. 5 shows an inward displacement channel (15) for the inward displacement of the roller chain (20).

In the case where the difference in the number of teeth between the two sprockets (3, 4) is also equal to the common divisor of the two numbers of teeth, i.e. when the sprockets have, for example, 40 and 50 teeth, the same type of shifting channels, i.e. 5 inward shifting channels (15) (upward shifting channels) and 5 outward shifting channels (16) (downward shifting channels), can be identical.

The position of the displacement channel (10) in the circumferential direction is generated as follows: the roller chain links (21, 22) also need to be well re-engaged on the tooth (30) on the target sprocket (9), that is, the tooth (30) can well enter the intermediate cavity between a pair of inner chain links or outer chain plates (24, 23). This corresponds to the phase conditions to be followed between adjacent sprockets (3, 4) where the displacement of the roller chain (20) should occur.

The inward displacement channel (15) extends radially outward from its radially inward lead-in side (11) to its lead-out side (12), which can be clearly seen in the figure at the edge of the recess (13) which is an essential component of the displacement channel. Due to the tilting of the roller chain (20) during the switching process from the smaller sprocket (4) to the larger sprocket (3), the depth of the recess (13) generally increases from the lead-in side (11) toward the lead-out side (12). In contrast, the inner chain plate (28) of the roller chain is not covered by the outer chain plate (27) at the position of the link (18) adjacent to the tooth during the outward displacement of the roller chain.

The inward (dorsal) side (5) of the larger sprocket (3) can be seen particularly clearly in Figure 6. Coarse and fine teeth (36, 37) follow alternately on the periphery, which requires an even number of teeth.

The coarse teeth (36) have a relatively coarse dimension in the direction parallel to the rotation axis on the inner side (5), so that although these coarse teeth (36) can enter the middle cavity between a pair of outer plates (23) located on the outer plate link (21), they do not fit on a pair of inner plates (24) located on the inner plate link (22). The coarse teeth (36) provide good guidance for the outer plate link (21) in the direction parallel to the rotation axis D.

The fine teeth (37) have a relatively fine dimension in a direction parallel to the rotation axis. They are adapted to be engaged on a pair of inner plates (24) located on the inner plate link (22). The fine teeth (37) provide good guidance for the inner plate link (22) in a direction parallel to the rotation axis D.

FIG. 5 shows the first engagement teeth (40) and the inward displacement channel (15) for the roller chain (20) to be displaced inwardly, and the inner chain plate passage teeth (45) of the outward displacement channel (16) for the roller chain (20) to be displaced outwardly.

In addition to the coarse and fine teeth (36, 37), FIG. 7 also shows the inward side (5) of the spatially set tooth (43) with a centering chamfer (44), the inward side (5) of the first switching tooth (40) with an engagement chamfer (42), and the inward side of the second engagement tooth (41).

FIG9 is a detailed view of the side view shown in FIG8, from which more details of the displacement channel (10) can be seen, in particular, two tabs (18), a bridge portion and a push chamfer (17).

Combining Figures 5 and 7, the operation of the inward switching process achieved by the sprocket (3, 4) of the present invention can be particularly clearly seen.

During the inward switching process, the chain links (21, 22) are first deflected radially inwardly on the outside in a manner passing by the tooth (30). They are also deflected in a manner passing by the spatially predetermined tooth (43), and then the inner outer chain plate (27) passes over the tooth tip (33) of the first engagement tooth (40) and slides radially inwardly on the inner side of the first engagement tooth (40), whereby contact is made with the engagement chamfer (42) provided on the inner side of the first engagement tooth (40). The engagement chamfer (42) is inclined and is more outward at the tooth tip (33) and further radially inwardly positioned more inwardly at the first engagement tooth (40).

The protrusion on the tooth tip of the space-giving tooth allows the inner plate links to pass radially inwards, while the outer plate links cannot. In this way, the protrusion realizes a softening function, which prevents the accidental introduction of outward switching operations on the inward displacement channel. The tooth tip of the space-giving tooth sinks into the intermediate cavity between a pair of outer plates and centers the outer plate links relative to the tooth row on the sprocket.

According to the spatially defined tooth (43) of the present invention, several functions are realized.

It provides space for the roller chain links to approach the larger sprocket (3).

It prevents the following situation: after the inner chain plate passes over the first switching tooth (40), the second switching tooth (41) following the first switching tooth (40) in the opposite direction of the driving rotation direction D engages with the outer chain plate link (21).

It prevents the chain from jumping during reverse pedaling.

It prevents the introduction of outward switching operations on the inward shift channel (15).

Before the outward switching operation is introduced, the chain link is engaged with the larger chain wheel (3), wherein the tooth (30) enters the middle cavity between the chain plate pair (23, 24).

At the start of the outward switching operation, the links continue to deflect radially inwards, but begin to move outwards in a manner passing by the teeth. As the first link, the inner plate link (22) is deflected in a manner passing by the passage teeth (45).

The subsequent links also require space because they have not yet moved sufficiently in an outward direction away from the larger sprocket (3). As shown in Figure 5, the necessary space is also provided on the larger sprocket on the outward side by the notch (13) of the outward displacement channel (16).

When the preferred embodiment's 42 vs. 52 tooth ratio is combined with the Xsync teeth on these sprockets, the roller chain from the smaller sprocket toward the outward shifting channel on the larger sprocket as shown on the left side of Figure 5 needs to be prevented from getting stuck on the larger sprocket (3) despite having room on the access teeth (45).

The tooth on the larger sprocket (3) that follows the passage tooth (45) opposite to the drive rotation direction D requires engagement of the outer plate link (21) because it is a coarse tooth (36). The further subsequent tooth opposite to the drive rotation direction is also provided with a push-out chamfer (17) for the push-out link, so that the chain is not radially driven outwards by the edge that would otherwise be present on the outer circumference of the unloaded tooth flank (32) of the tooth and on the tooth root (38). The push chamfer (17) shown in FIGS. 5 and 9 starts on the flat surface (7) and inclines away from this flat surface (7) in its extension to the outer contour of the tooth on the unloaded tooth flank (32), to the tooth root (38) or to the tooth tip (33).

If the smaller sprocket is not an Xsync sprocket, i.e. does not have coarse teeth, then, subject to additional conditions (e.g. an odd number of teeth on the smaller sprocket (4)), the roller chain (20) engages on the tooth that follows the passage tooth (45) on the larger sprocket (3) in the opposite direction to the drive rotation direction D. In this case, the push chamfer (17) is also not required.

During the reverse pedaling process, the chain links (21, 22) that follow one another along the driving rotation direction D move radially inward one after another, wherein the teeth start from the tooth tips (33) and enter the middle cavity of each chain plate pair (23, 24).

In larger sprockets, the inclination of the chain towards the front sprocket is particularly pronounced, so there is a tendency for the inner chain link (22) to pass through a tooth (30) to the outside, which can lead to an accidental switch to an adjacent smaller sprocket (4) or even a chain jump, and needs to be avoided. For example, the tooth with a notch on the outside of the spatially set tooth (43) provides an excellent prerequisite for this misoperation.

In the case of the space-giving tooth (43) of the present invention, the tooth tip (33) is staggered outward and can still well enter the space between a pair of chain plates (23, 24). Subsequently, the inner chain plate on the inward side slides radially inward on the centering slope provided on the space-giving tooth on the inward side, and the inner chain plate is centered relative to the tooth row on the sprocket.

In the embodiment of the present invention shown, the radially outer inward side of the inner link plate link (22) of the roller chain (20) is axially supported on the protrusion (14), and the radially inner inward side of the inner link plate can still be fully immersed in the recess in the inward direction due to possible torsion in the roller chain (20).

In a further embodiment of the present invention with a tooth number difference of more than 10, the radially inner edge of the protrusion 14 can be positioned further radially outward, and the chain plate has sufficient space, so it is no longer necessary to twist the chain.

Figures 14 to 16 show another construction scheme of the outward displacement channel according to the present invention.

The displacement channel has an outward notch, a passage tooth (45) on the radially outer introduction side (11), and a protrusion (14) on the tooth tip (33) of the passage tooth (45).

The radially outer edge of the outlet side (12) of the recess (13) is located radially inwardly relative to the tooth (30) following the passage tooth (45) in the opposite direction to the drive rotation direction D.

In this embodiment of the invention, the larger and smaller of the adjacent sprockets have an even number of teeth, and the coarse teeth and the fine teeth alternate circumferentially ("Xsync"), as disclosed in DE 102012023819. However, the concept of the invention is not limited thereto.

It is also possible to adopt the larger target sprocket as an XSync sprocket, but the adjacent smaller sprocket is not an XSync sprocket solution. Therefore, even in the specific case where there are outer chain plate links adjacent to the protrusions on the teeth, the protrusions in the recess can be used to support the outer chain plate radially and achieve synchronization of the chain with the teeth on the larger sprocket.

The concept of the present invention can also be applied to a chain wheel without coarse and fine teeth. In this case, during the inward switching process, the switching achieved through the inner chain plate channel on the first sharp tooth is deliberately abandoned by adopting a corresponding tooth design. In this way, one of the two switching schemes is abandoned. On the other hand, it is advantageous in preventing the chain from falling off during reverse pedaling and preventing accidental outward switching.

The invention has been described above using the largest sprocket in a multiple configuration of rear sprockets as an example. Due to its nature, it is not necessary to provide a switching aid on such a sprocket to shift the roller chain to an adjacent larger sprocket. However, the characteristics described are applicable to sprockets adjacent to a larger sprocket, because only when the difference in the number of teeth is 1 to 2 teeth is it necessary to provide a switching aid on the corresponding sprocket, and it is necessary to shift the chain from the sprocket to the adjacent larger sprocket. This is not the case in the present case.

3: Larger sprocket

4: Smaller sprocket

15: Inward shift channel

16: Outward shift channel

Claims (17)

A multi-sprocket arrangement (1) comprises a larger sprocket (3) and a smaller sprocket (4), the multi-sprocket arrangement being used for being mounted on the rear wheel of a bicycle, wherein the larger sprocket (3) is arranged on an inner side (5) relative to the smaller sprocket (4) and the smaller sprocket (4) is arranged on an outer side (6) relative to the larger sprocket (3) when viewed along the axial direction. The larger sprocket and the smaller sprocket have: a plurality of teeth (30) including tooth tips (33) located on the radial outer periphery of the sprockets (3, 4) for engaging with the links (21, 22) of the roller chain (20); a flat surface (7) located on the outer side of the sprockets (3, 4); and a flat surface (7) for switching from the smaller sprocket (4) to the larger sprocket (3) in the inward direction. The invention relates to an inward displacement channel (15) that cooperates with the roller chain (20) of the larger sprocket (3); wherein the inward displacement channel (15) includes: a notch (13) located on the outward side (6) of the larger sprocket (3), the notch extending on its radially outer introduction side (11) to a spatially given tooth (43); and an inward first engagement tooth (40) located on the larger sprocket (3). The invention relates to a first engaging chamfer (42) on the side (5), wherein the first engaging tooth closely follows the spatially given tooth (43) in a direction opposite to the driving rotation direction (D); the invention is characterized in that a protrusion (14) located on the spatially given tooth (43) is provided in the recess (13), and the protrusion (14) rises substantially to a plane through which the flat surface (7) passes relative to the recess (13) in an outward direction. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the protrusion (14) has a contact surface (14a) for contacting the inner chain plate (28) of the roller chain (20), and a contact force is generated in the contact surface to act axially on the roller chain (20) to axially push the roller chain (20) outward. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the space-given tooth (43) has a centering chamfer (44) located on the inner side (5) for cooperating with the inner surface (29) of an inner chain plate (28) of the inner chain plate pair of the roller chain (20), the inner chain plate pair of the inner chain plate pair of the roller chain (20) The inner surface of the inner chain plate is opposite to the inner surface (29) of the other inner chain plate (28) of the inner chain plate pair (24); therefore, the space-given tooth (43) reliably enters the middle cavity between the inner chain plate pair (24) along the radial direction, and the inner chain plate link (22) is centered relative to the sequence of the teeth (30) on the larger chain wheel (3). The larger sprocket (3) and the smaller sprocket (4) of the multi-sprocket arrangement (1) of claim 3, wherein the centering chamfer is configured such that during reverse pedaling, the teeth (30) that are successively engaged with the teeth (30) on the larger sprocket (3) in the opposite direction of the driving rotation direction (D) reliably enter the middle cavity between the chain plate pair (23, 24) along the radial direction, thereby preventing the chain from falling off; and/or, In the rotational movement along the driving rotational direction (D), the teeth (30) that are successively engaged with the teeth (30) on the larger sprocket (3) reliably enter the middle cavity between the chain plate pair (23, 24) of the roller chain (20) along the radial direction without being displaced in the outward direction, and the roller chain (20) does not accidentally switch from the larger sprocket (3) to the smaller sprocket (4). A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the depth of the section of the recess connected inwardly to the protrusion is less than the depth of the section of the recess connected to the given tooth in the space along the rotational direction, and a tab (18) is formed to provide space for the inner chain plate (28). A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1 or 2, wherein the outward side of the first engagement tooth has a substantially flat surface extending substantially in the plane of the flat surface (7) for achieving contact with the outer side of the inner chain link (22) of the roller chain (20). A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the difference between the number of teeth on the larger sprocket (3) and the number of teeth on the smaller sprocket (4) is at least 10. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the larger sprocket (3) has an even number of teeth (30), and the teeth (30) are alternately implemented as coarse teeth and fine teeth along the axial direction. A larger sprocket (3) and a smaller sprocket (4) of the multi-sprocket arrangement (1) of claim 1, wherein the tooth tip has a supporting surface capable of contacting an outer chain plate (27) of the roller chain (20) to support the outer chain plate in a radial direction. A larger sprocket (3) and a smaller sprocket (4) of the multi-sprocket arrangement (1) of claim 1, wherein the larger sprocket (3) has 52 teeth. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 1, wherein the smaller sprocket has an even number of teeth, and the teeth are alternately implemented as coarse teeth and fine teeth along the axial direction. A multi-sprocket arrangement (1) having a larger sprocket (3) and a smaller sprocket (4), the multi-sprocket arrangement being used for being mounted on the rear wheel of a bicycle, wherein the larger sprocket (3) is arranged on an inner side (5) relative to the smaller sprocket (4) and the smaller sprocket (4) is arranged on an outer side (6) relative to the larger sprocket (3) when viewed along the axial direction, and the larger sprocket and the smaller sprocket of the multi-sprocket arrangement have: a plurality of radially outer circumferences of the sprockets (3, 4) a tooth portion (30) including a tooth tip (33) for engaging with a link (21, 22) of a roller chain (20); a flat surface (7) located on the outward side of the sprockets (3, 4); an outward displacement channel (16) for cooperating with the roller chain (20) switching from the larger sprocket (3) to the smaller sprocket (4) in an outward direction; wherein the outward displacement channel (16) includes: a notch (13) located on the outward side (6) of the larger sprocket (3); and a passage tooth (45) located on the radially outer leading side (11) of the outward displacement channel (16); characterized in that a protrusion (14) is provided on the outer side of the tooth (30) following the passage tooth (45) in the opposite direction to the driving rotation direction (D) in the recess (13); wherein the protrusion (14) rises substantially to a plane through which the flat surface (7) passes relative to the recess (13) in the outward direction, and forms a bridge portion (19) following the outer contour of the tooth root. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 12, wherein the difference between the number of teeth on the larger sprocket (3) and the number of teeth on the smaller sprocket (4) is at least 10. A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 12 or 13, wherein the depth of the recess (13) at the passage tooth (45) is less than the depth of the section of the recess (13) extending radially inward from the tooth portion (30) following the passage tooth (45) in the opposite direction to the driving rotation direction (D), thereby forming a tab (18). A larger sprocket (3) and a smaller sprocket (4) of a multi-sprocket arrangement (1) as claimed in claim 12, wherein a protrusion (14) is provided outwardly on the tooth tip (33) of the passage tooth (45), which rises substantially to the plane through which the flat surface (7) passes. The larger sprocket (3) and the smaller sprocket (4) of the multi-sprocket arrangement (1) of claim 12, wherein a plurality of teeth (30) following the passage teeth (45) in the opposite direction to the driving rotation direction (D) are provided with a push chamfer (17) on the outward side, so that no radially acting support point is generated against the outer periphery of the outer chain plate (27). A larger sprocket (3) and a smaller sprocket (4) of the multi-sprocket arrangement (1) of claim 12, wherein the larger sprocket (3) has 52 teeth.

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