JP3021291U - Bicycle gearbox - Google Patents

Abstract

(57) An object of the present invention is to provide a transmission gear set that can assist when a chain rapidly moves to a gear having a different diameter due to a gear change so that the movement can be reliably and smoothly achieved. SOLUTION: A large gear 1, a middle gear 2 and a small gear 3 provided on the same shaft are provided, and an inner side surface 10 facing the middle gear 2 of the large gear 1 is changed from a small gear 3 to a middle gear 2 by a gear change. Is provided with a projection formed on an arcuate convex surface for assisting the movement of the chain to the. Further, in the vicinity of the guide claw 12 on the inner side surface 10 facing the middle gear 2 of the large gear 1, the guide claw 12 is connected to the coupling link plate of the chain when the chain is moved from the gear having a large diameter to the gear having a small diameter by gear change. Protrusions 13 are provided to prevent hooking.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a transmission gear set for a bicycle in which a plurality of gears having different diameters are provided on the same shaft, and particularly when the chain is rapidly moved to a gear having a different diameter by a gear change, the movement thereof is ensured. The present invention also relates to a variable speed gear set for a bicycle, which has an auxiliary effect that can be achieved smoothly.

[0002]

[Prior art]

 A well-known bicycle speed change gear set is generally constructed by mounting a plurality of gears having different diameters on the same shaft in order according to the diameter size. Then, the transmission moves the chain from the small gear to the large gear or from the large gear to the small gear to achieve the purpose of speed change.

Further, in a conventional bicycle transmission gear set, for example, a bicycle transmission gear set having three gears of different sizes, large, medium and small, when a chain is moved from a small gear to a middle gear and engaged with the chain. In order to prevent the chain from slipping between the gears and causing friction, and to facilitate the movement of the chain, a guide claw is provided on the inner surface facing the small gear of the middle gear. When the chain moves, the joint link plate of the chain hits the guide claw to engage the middle gear without the chain coming off. Further, such guide claws are also provided on the inner surface facing the middle gear of the large gear to achieve the same purpose.

[0004]

[Problems to be solved by the device]

 In the conventional shift gear set described above, for example, a bicycle shift gear set having three gears of different sizes, large, medium and small, one point in Fig. 6 is shown when the chain rapidly moves from the small gear to the middle gear. As indicated by the chain line, the chain excessively extends in the lateral direction rather than the large gear, and it often slides to cause friction without being caught by the middle gear, producing friction noise and becoming noise. Therefore, it is difficult to move the chain from the small gear to the middle gear rapidly and accurately to engage the chain.

Further, the guide claws have an effect of assisting the movement of the chain, but when the timing of gear change is inappropriate, the chain is loose, or the guide claws are worn. If so, the joint link plate of the chain will not accurately hit the guide claws, making it difficult to move the chain.

Furthermore, when the chain moves from the gear with the large diameter to the gear with the small diameter, a condition occurs in which the coupling link plate of the chain is caught by the guide claws and the chain cannot move to the gear with the small diameter. However, it may cause a gear change malfunction.

The present invention has been developed to overcome the above-mentioned drawbacks of the prior art in a bicycle transmission gear set, which is configured by sequentially mounting a plurality of gears having different diameters on the same shaft according to the diameter size. When the chain is rapidly moved from the small gear to the middle gear, the chain guides in the right direction without excessively extending laterally from the large gear and engages with the middle gear quickly and accurately. An object is to provide a variable speed gear set for a bicycle that can be used.

Another object of the present invention is to provide a transmission gear set for a bicycle, which can surely achieve the operation when moving a chain from a small gear to a large gear.

The present invention further provides a bicycle shift gear set in which a guide claw is provided on an inner surface of a large-diameter gear adjacent to a small-diameter gear, and a chain from the large-diameter gear to the small-diameter gear is chained. An object of the present invention is to provide a transmission gear set for a bicycle, which retains the effect of assisting the movement of the gears of the guide claws when moving the gears and does not catch the guide claws on the joint link plate of the chain.

[0010]

[Means for Solving the Problems]

 According to one aspect of the present invention, there is provided a bicycle transmission gear set for a bicycle, comprising at least a large gear, a middle gear, and a small gear provided on the same shaft. The feature is that the inner surface of the large gear facing the middle gear is provided with a protrusion that assists the chain movement from the small gear to the middle gear by a gear change.

Further, in another aspect, the bicycle speed change gear set of the present invention has a large gear and a small gear that are provided on at least the same shaft, and has a surface facing the small gear of the large gear. In a bicycle transmission gear set that has a guide claw, the guide claw is connected to the chain joint when the chain is moved from the large gear to the small gear due to a gear change near the guide claw on the inner surface facing the small gear of the large gear. It is characterized in that a protrusion is provided to prevent the link plate from being caught.

Further, the bicycle transmission gear set of the present invention is, in still another aspect, a bicycle transmission gear set having a large gear and a small gear provided on at least the same shaft. Near the bottom of the tooth groove of the inner surface facing the small gear, a protruding auxiliary guide claw that assists the chain change from the small gear to the large gear by the gear change is provided. It is characterized by forming a gap with the inner surface of the large gear to which the joint link plate of the chain fits.

[0013]

[Embodiment]

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 discloses an example of a set of three gears. However, the technology of the present invention and its features are not limited to those including a set of three gears.

First, as shown in FIGS. 1 and 2, the bicycle gearshift gear according to the present embodiment has a large gear 1 and a middle gear 1 arranged in order on the same axis according to the size of the diameter (or the number of teeth). It is composed of a gear 2 and a small gear 3. The large gear 1 is provided with an arcuate projection 11 projecting from the inner side surface 10 at a position near the tooth root of the gear on the inner side surface 10 facing the middle gear 2. At the same time, an auxiliary guide claw 12 that vertically protrudes from the inner side surface 10 and assists the chain movement due to the gear change from the small diameter gear to the large diameter gear is provided slightly below the bottom of the tooth groove. An auxiliary protrusion 13 is separately provided at a position of about 1 pitch from the direction opposite to the forward direction of the gear from the claw 12. The above-mentioned projection 11 and auxiliary projection 13 are both formed in an arc shape and project from the inner surface of the gear, and the auxiliary guide claw 12 projects from the inner surface of the gear as disclosed in FIG. Between the bottom outer side (side facing the gear) and the inner side 10 of the gear, there is provided a gap G into which the joint link plate of the chain fits.

The protrusion 11, the auxiliary protrusion 13 and the guide claw 12 are formed by press molding from the outer surface of the gear by using the gear manufacturing material itself when molding the gear, or the protrusion member or the guide claw member. Is manufactured separately, and is joined and fixed to the side surface of the gear by means of welding or the like. The heights of the protrusion 11 and the auxiliary protrusion 13 are the same as those of the auxiliary guide claw 12 or are formed such that the apex thereof is slightly higher than the auxiliary guide claw 12.

Further, as disclosed in FIG. 1, a columnar protrusion 20 protruding from the inner side surface is provided below a slight bottom of the tooth groove on the inner side surface facing the small gear 3 of the middle gear 2. The guide claw 20 is provided below the bottom of the tooth groove at a position where the gear of the protrusion 20 is located at about 1 pitch in the reverse direction of the forward direction. The shapes, heights, and molding methods of the protrusion 20 and the auxiliary claw 21 are the same as those of the auxiliary protrusion 13 and the auxiliary guide claw 12 provided on the large gear, and thus the description thereof will be omitted.

The protrusion 11 of the large gear 1 and the other auxiliary protrusion 13 or the protrusion 20 of the middle gear 2 are provided for different purposes respectively, and the protrusion 11 of the large gear 1 contacts the chain. It is provided for the purpose of preventing the chain from excessively extending laterally toward the large gear when the chain is rapidly moved from the small gear to the middle gear.

In addition, the projection 13 of the large gear 1 or the projection 20 of the middle gear 2 has guide claws for connecting the chain link plate of the chain when the chain is rapidly moved from a gear having a large diameter to a gear having a small diameter. It is provided for the purpose of preventing hooking. Since both parties do not depend on each other, any one of them may be selected and provided, or both may be provided.

Although one embodiment of the present invention has been described above, in practice, many design changes are made for the same technical purpose as the above embodiment, and the chain is moved by a gear change. It is possible to strengthen the auxiliary effect that makes the operation reliable and smooth. For example, as disclosed in FIG. 9, by providing a cutting portion T on the side surface of the gear tooth at the position where the auxiliary guide claw is provided, a gap formed between the joint link plate of the chain and the auxiliary guide claw is provided. The engagement facilitates movement of the chain, while at the same time the presence of the cutting portion T allows the chain to more easily mesh with the teeth of the gear having the cutting portion T. According to the experiment by the present inventor, by arranging these, the chain can be more completely moved by the gear change.

Therefore, the above is only one embodiment of the present invention and does not limit the scope of the claims. Any design changes that can be made based on the purpose of the present invention and its effects shall fall within the scope of the claims.

Next, the operation of the above-described embodiment of the present invention will be described. As shown in FIGS. 5 and 6, when the chain 4 is engaged by the small gear 3 that rotates when the bicycle is driven, and the driver rapidly operates the transmission (not shown) to perform the gear change. That is, when the small gear 3 is changed to the middle gear 4 as shown in FIG. 5, in the conventional gear set, as shown by the chain line in FIG. Since the chain 4 excessively extends in the lateral direction, the engagement operation of the chain 4 with the middle gear is not reliably performed. Therefore, the chain 4 slides and hits the inner surface of the large gear 1 to generate noise due to friction.

However, in this embodiment, since the projection 11 is provided at a position near the tooth base of the large gear 1, the joint link plate (inner or outer plate) of the chain 4 can be changed. In such an operation, the protrusion 11 has a function of preventing the lateral extension of the chain 4 and guiding the chain 4 so that the chain 4 can be properly moved, and the chain 4 performs an accurate operation according to the gear change operation. 6. Engage with the teeth of the middle gear, as shown by the alternate long and short dash line in FIG.

When the chain 4 is guided from the small gear 3 to the middle gear 2 by the gear change operation, the joint link plate 40 of the chain 4 is attached to the auxiliary guide claw 21 of the middle gear 2 as shown in FIG. By fitting in the gap G provided, there is no possibility of the chain 4 slipping off, and the movement operation of the chain 4 to the middle gear 2 is surely achieved. Even when the chain 4 moves from the middle gear 2 to the large gear 1, the guide action exerted by the auxiliary guide claw 12 of the large gear 1 is the same as that described above, and therefore its description is omitted.

Further, as shown in FIG. 5 and FIG. 6, the chain 4 is engaged by the middle gear 2 that rotates when the bicycle is driven, and the driver rapidly operates the transmission (not shown). When the gear is changed and the chain is moved from the middle gear 2 to the small gear 3 as shown in FIG. 7, the joint link plate of the chain 4 comes into contact with the protrusion 20 first as shown in FIG. The link plate does not get too close to the auxiliary guide claws 21 and get caught. Therefore, the chain 4 moves smoothly and engages with the small gear 3. Similarly, the protrusion 13 of the large gear 1 prevents the auxiliary guide claw 12 from being caught when the chain 4 moves from the large gear 1 to the middle gear 2.

As described above, the protrusions 11 provided on the large gear 1 of the present embodiment can reliably and smoothly move the chain 4 even if the chain 4 is rapidly moved from the small gear 3 to the middle gear 2. Further, since the inner guide surfaces of the large gear 1 and the middle gear 2 are formed with auxiliary guide claws 12 and 21 each having a gap G at the outer bottom, the chain 4 has a small diameter. The movement to a gear with a large diameter is very reliably performed.

Since the middle gear 2 has the protrusion 20 formed in the vicinity of the auxiliary guide claw 21, the joint link plate of the chain 4 assists when the chain 4 is moved from the gear having a large diameter to the small gear 3. Does not get caught on the guide claws. Therefore, the small gear 3 can be smoothly moved into engagement with the small gear 3, and the drawbacks of the known technique can be sufficiently solved. The auxiliary projection 13 formed in the vicinity of the auxiliary guide claw 12 of the large gear 1 also has the same effect.

[Brief description of drawings]

FIG. 1 is a diagram showing an inner surface of a bicycle transmission gear set according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a part of a circle II in FIG.

FIG. 3 is a perspective view of a portion of a circle III in FIG.

FIG. 4 is a view showing a cross section taken along line IV-IV of FIG. 3.

FIG. 5 is a diagram showing a state in which the chain moves from the small gear to the middle gear in the embodiment of the present invention.

6 is a development view of the chain moving operation by gear change, as viewed from the direction of arrow VI in FIG.

FIG. 7 is a diagram showing a state of movement of the chain from the middle gear to the small gear in the embodiment of the present invention.

8 is a development view showing the movement operation of the chain due to a gear change, as viewed from the direction of arrow VIII in FIG.

FIG. 9 is a perspective view showing a state in which cutting portions T for further improving the action of the guide claws are formed on the teeth of the gear in the embodiment of the present invention.

[Explanation of symbols]

 1 Large Gear 2 Medium Gear 3 Small Gear 4 Chain 10 Inner Side of Large Gear 11 Large Gear Projection 12 Large Gear Auxiliary Guide Claw 13 Large Gear Auxiliary Projection 20 Medium Gear Projection 21 Medium Gear Auxiliary Guide Claw 40 Chain Joint link plate G Gap between auxiliary guide claws T Cutting part

Claims (7)

[Scope of utility model registration request] 1. A bicycle transmission gear set having a large gear, a middle gear, and a small gear provided on at least the same shaft, wherein a gear change is made on an inner surface of the large gear facing the middle gear. A shift gear set for a bicycle, comprising a protrusion for assisting chain movement from the small gear to the middle gear. 2. A bicycle speed change gear set, comprising: a large gear and a small gear provided on at least the same shaft, wherein a guide claw is provided on a surface of the large gear facing the small gear. A protrusion that prevents the guide claw from catching the joint link plate of the chain when the chain is moved from the large gear to the small gear due to a gear change, in the vicinity of the guide claw on the inner surface of the large gear facing the small gear. A transmission gear set for a bicycle, characterized by being provided with. 3. The shift gear set for a bicycle according to claim 1, wherein the protrusion is formed in an arcuate convex surface. 4. The shift gear set for a bicycle according to claim 2, wherein the protrusion is provided below the tooth groove bottom of the large gear at a pitch of 1 pitch from the guide claw. 5. The bicycle transmission gear set according to claim 4, wherein the protrusion is formed at substantially the same height as the guide claw. 6. A bicycle speed change gear set having a large gear and a small gear provided on at least the same shaft, wherein a gear is provided on an inner side surface of the large gear facing the small gear, in the vicinity of a tooth groove bottom portion of the gear. A protrusion-shaped auxiliary guide claw for assisting the chain movement from the small gear to the large gear due to a change is provided, and the auxiliary guide claw is a joint link plate of the chain between the outer bottom portion and the inner side surface of the large gear. A transmission gear set for a bicycle, characterized in that it forms a gap for fitting with each other. 7. A cutting portion on a side surface of a tooth of the large gear is formed to enhance an effect of guiding the chain movement of the auxiliary guide claw from the small gear to the large gear due to a gear change. The bicycle transmission gear set according to claim 6.