TWI677453B - Bevel gear device of transmission shaft - Google Patents

Abstract

An umbrella gear device for a transmission shaft is suitable for connecting the transmission shaft and a hub of a bicycle, and the hub is sleeved on a shaft. The umbrella gear device includes an umbrella gear unit and a dry bearing unit. The umbrella tooth unit has an umbrella tooth for engaging the transmission shaft, and a unidirectional transmission coupling group for unidirectional transmission of the rotation of the hub. The ratio of the diameter of the shaft to the maximum outer diameter of the bevel is 0.164 ~ 0.24. By setting the umbrella teeth and the unidirectional transmission coupling group respectively at both ends of the umbrella tooth unit, the transmission shaft can be connected, and the hub can be driven to rotate in one direction. The umbrella tooth unit can be universally used with the shaft transmission system components on the market and can effectively reduce the volume and weight while maintaining the required speed ratio.

Description

Bevel gear device of transmission shaft

The invention relates to a bevel gear device for a transmission shaft, in particular to a bevel gear device for a transmission shaft of a bicycle.

Traditional bicycles are equipped with a chain and a chainring to drive the bicycle body forward. Referring to FIG. 1, in recent years, there is a design using a transmission shaft 91 and a gear 92. The transmission shaft 91 cooperates with the gear 92 to drive a hub 93 of a bicycle. Wherein, the transmission shaft 91 has a gear portion 911 that meshes with the gear 92. When the transmission shaft 91 is driven to rotate by a transmission element such as a crank of a bicycle, the hub 93 can be driven through the gear portion 911 and the gear 92 Rotate to achieve the purpose of advancing the bicycle body, thereby replacing the traditional chain and chainring. However, the gear 92 generally needs a locking structure to cooperate with the hub 93. Therefore, the gear 92 needs a certain volume, and the large volume will increase the weight, which not only increases the manufacturing cost but also the overall weight. Therefore, this case is aimed at The gear 92 element matched with the transmission shaft 91 is researched and improved.

It is therefore an object of the present invention to provide a bevel gear device for a transmission shaft that overcomes at least one of the disadvantages of the prior art.

Therefore, the bevel gear device of the drive shaft of the present invention is suitable for connecting the drive shaft and a hub of a bicycle, and the hub is sleeved on a shaft of the bicycle. The bevel gear device of the drive shaft includes an umbrella gear unit, and One dry-type bearing unit.

The bevel gear unit has an opposite first end and a second end, an bevel gear located on the first end and adapted to engage the transmission shaft, and a bevel gear located on the second end and adapted to be unidirectional A unidirectional transmission coupling group for driving the rotation of the hub. The ratio of the diameter of the shaft to the maximum outer diameter of the bevel is 0.164 ~ 0.24. The dry-type bearing unit is installed in the bevel gear unit and is used for smoothly rotating the bevel gear unit.

The effect of the present invention is that the umbrella teeth and the one-way transmission coupling group are respectively provided at two opposite ends of the umbrella tooth unit, so that the transmission shaft can be connected and the hub can be driven to rotate in one direction. The ratio of the diameter of the shaft to the maximum outer diameter of the umbrella teeth is limited, which meets the required transmission ratio and the size of the umbrella teeth structure. Therefore, the umbrella tooth unit can not only be used in common with the shaft drive system components on the market, but also maintain Under the required speed ratio, it can effectively reduce the volume and weight. The dry bearing unit enables the present invention to achieve the function of installing the bevel gear unit without additional design of a locking structure or element, and allows the bevel gear unit to rotate smoothly, and the bevel gear unit can also smoothly drive the hub to rotate , So that the power transmission performance is good.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are represented by the same numbers.

Referring to FIGS. 2, 3 and 4, a first embodiment of an umbrella gear device of a transmission shaft 11 according to the present invention is suitable for connecting the transmission shaft 11 and a hub 12 of a bicycle, and one end of the transmission shaft 11 is adjacent to a bicycle The other end of the crank (not shown) is far from the crank and has a coupling portion 111, which includes an umbrella tooth 112. The hub 12 includes a body portion 121 and a shaft portion 122. The main body 121 has an end surface 123 and a plurality of ratchet teeth 124. The shaft portion 122 extends axially from an end surface 123 of the main body portion 121. The bicycle also includes a shaft 13, which is assembled on the rear frame, and the hub 12 is sleeved on the shaft 13 and can rotate relative to the shaft 13. The body portion 121 and the shaft portion of the hub 12 122 surrounds the shaft 13. The umbrella tooth device includes an umbrella tooth unit 2, a dry bearing unit 3, and an end cover 4.

The bevel tooth unit 2 is adapted to be assembled with the hub 12 and includes a sleeve 21 having a first end portion 201 and a second end portion 202 opposite to each other, a first end portion 201 and suitable for engagement. The umbrella teeth 22 of the coupling portion 111 of the transmission shaft 11 and a unidirectional transmission coupling group 23 located on the second end portion 202 and adapted to unidirectionally transmit the rotation of the hub 12.

The sleeve 21 is axially sleeved on the shaft portion 122 of the hub 12 and has an inner peripheral surface 211 surrounding the shaft portion 122. The number of teeth of the umbrella teeth 22 is matched with the number of teeth of the umbrella teeth 112 of the joint portion 111. The number of teeth of the umbrella teeth 22 is preferably 14 to 24, and more preferably 15 to 20. The result of this range The size of the umbrella teeth 22 can be matched with the matching number of teeth, modulus, and speed ratio. The required gear ratio can be provided by the above-mentioned appropriate number of 22 teeth of the umbrella. Preferably, the ratio (ie, d1 / d2) of the diameter d1 of the shaft 13 and the maximum outer diameter d2 of the umbrella tooth 22 is 0.164 to 0.24. More preferably, the ratio is 0.188 to 0.237. By designing the above ratio and the number of teeth of the umbrella teeth 22, the maximum outer diameter of the umbrella teeth 22 is smaller than the maximum outer diameter of the existing umbrella teeth assembled there. Therefore, the overall size and weight of the umbrella teeth unit 2 of the present invention are small. light.

The one-way transmission coupling group 23 has a plurality of groove surfaces 232 formed on the outer peripheral surface of the sleeve 21 and respectively defining a groove 230, and a plurality of groove surfaces 232 arranged at equal angular intervals and installed on the groove surfaces 232, respectively. Pawl 231. The pawls 231 are adapted to mesh with the ratchet teeth 124 of the wheel hub 12 to drive the wheel wheel 12 to rotate in one direction only in the direction of advancing the bicycle. It is worth mentioning that when the present invention is implemented, the positions of the pawl and the ratchet teeth are interchangeable, that is, the body portion 121 of the hub 12 may be provided with a plurality of pawls, and the one-way transmission coupling group 23 has a number of Ratchet teeth formed on the sleeve 21, at this time, the sleeve 21, the umbrella teeth 22 and the ratchet teeth can be connected into a whole. On the other hand, the ratchet teeth can also constitute a component and be assembled on the sleeve 21, so that the one-way transmission coupling group 23 can also drive the hub 12 in one direction.

It is worth mentioning that the sleeve 21 and the umbrella teeth 22 of the umbrella tooth unit 2 of the first embodiment are integrally connected with the groove surfaces 232, and the pawls 231 are installed in the groove 230. And other components have good coaxiality.

The dry-type bearing unit 3 is installed in the bevel tooth unit 2 and includes a first bearing 31 and a second bearing 32 which are sleeved around the shaft portion 122 of the hub 12. The first bearing 31 is disposed at the end surface 123 of the body portion 121 and the inner peripheral surface 211 of the sleeve 21, and has a stop portion 311 located on the end surface 123. The stop portion 311 connects the end surface 123 and The bevel tooth units 2 are spaced apart. The second bearing 32 is located between the shaft portion 122 of the hub 12 and the inner peripheral surface 211 of the sleeve 21 to separate the shaft portion 122 from the bevel gear unit 2. With the dry bearing unit 3, the umbrella tooth unit 2 can be smoothly rotated after being driven. Moreover, the advantage of using a dry bearing instead of other types of bearings (such as ball bearings) is that the dry bearing structure is small and can be matched with the bevel gear unit 2 of the present invention having a small volume and an outer diameter, which is suitable for precision applications such as bicycles. , Small scale device. Dry bearings have good self-lubricating properties. They are oil-free bearings and are easy to use.

The end cover 4 is coupled to the vicinity of the first end portion 201 of the umbrella tooth unit 2 and surrounds the shaft portion 122 of the hub 12 to position the relative position between the umbrella tooth unit 2 and the hub 12 so that the umbrella teeth After the unit 2 is sleeved on the shaft portion 122, it will not be displaced due to vibration caused by the operation to avoid affecting the transmission efficiency.

In use, the user pedals the pedal of the bicycle in a forward direction and rotates the transmission shaft 11 around its own central axis through a crank, so that the umbrella tooth unit 2 can be driven through the umbrella teeth 112 of the coupling portion 111 Rotate, thereby driving the hub 12 to rotate, so as to drive the bicycle forward. When the user depresses and rotates the pedal in the backward direction, although the umbrella tooth unit 2 will be driven to rotate in the reverse direction, because the pawl 231 of the one-way transmission coupling group 23 and the ratchet tooth 124 of the hub 12 are matched, The bevel gear unit 2 only idles, does not drive the hub 12 to rotate, and does not cause the bicycle to retreat.

In summary, the umbrella teeth 22 and the one-way transmission coupling group 23 are respectively provided at two opposite ends of the umbrella tooth unit 2, and are connected to the transmission shaft 11 through the umbrella teeth 22 on the one hand, and on the other hand through the single The drive coupling group 23 drives the hub 12 to rotate in one direction, and since the pawl 231 and the ratchet teeth 124 of the hub 12 of the one-way transmission coupling group 23 are the same as the general specifications of the axle transmission system of a common bicycle, the umbrella gear device It can be directly assembled on a commercially-available wheel hub 12, so there is no need to specially develop wheel sets or other parts with special specifications. Matching the umbrella teeth 22 has an appropriate number of teeth, and the ratio of the diameter of the shaft 13 to the maximum outer diameter of the umbrella teeth 22 is limited, which meets the required transmission ratio and the structure size of the umbrella teeth 22, so that the invention can maintain Under the required speed ratio, it can effectively reduce the volume and weight. The dry bearing unit 3 enables the present invention to achieve the function of installing the umbrella tooth unit 2 without additional design of a locking structure or element, so that the umbrella tooth unit 2 and the hub 12 are firmly combined, and the umbrella tooth unit 2 can rotate smoothly. The umbrella tooth unit 2 can also smoothly drive the hub 12 to rotate, so that the power transmission efficiency is good.

5 and 6, a second embodiment of a bevel gear device of a transmission shaft of the present invention has substantially the same structure as the first embodiment, except that the bevel gear unit 2 of the second embodiment is assembled by several components. It is formed and includes a mandrel 24 having the first end portion 201, a mounting seat 25 for the mandrel 24 to be inserted and extended and having the second end portion 202, and a plurality of fixing members 26. The umbrella tooth 22 is formed at a first end portion 201 of the core shaft 24, and the one-way transmission coupling group 23 is located at a second end portion 202 of the mounting seat 25. The mounting seat 25 has a surrounding wall 251 that defines an installation space 250 for the mandrel 24 to extend into. The surrounding wall 251 has an inner peripheral surface 252 surrounding the mandrel 24, and an opposite side to the inner wall. An outer peripheral surface 253 of the peripheral surface 252 and the surrounding wall 251 are formed with a plurality of screw holes 254 extending from the outer peripheral surface 253 to the inner peripheral surface 252 and communicating with the installation space 250. The fixing members 26 are screws and are respectively locked through the screw holes 254. One end of the fixing member 26 abuts against the surface of the mandrel 24 to fix the mandrel 24 and the mounting seat 25.

In the second embodiment, the two components of the core shaft 24 and the mounting base 25 are assembled and assembled, and the umbrella shaft 22 and the one-way transmission coupling group 23 are provided on the core shaft 24 and the mounting base 25, respectively. The transmission shaft 11 (FIG. 2) and the hub 12 are connected to achieve the same effect as the first embodiment. In addition, the two-piece component has the advantages of easy processing and mass production. When manufacturing, the mandrel 24 can facilitate the positioning of the fixture to form the umbrella teeth 22.

Referring to FIG. 7, a third embodiment of a bevel gear device of a transmission shaft of the present invention has substantially the same structure as the first embodiment, except that the sleeve 21 of the third embodiment includes a main body section 212, and A mandrel section 213 extending forward from the main body section 212 and having an outer diameter smaller than that of the main body section 212. The main body section 212 has the second end portion 202, and the mandrel section 213 has the first end portion 201. The umbrella teeth 22 are fixed on the mandrel section 213 of the sleeve 21 by a tight fit.

However, the above are only examples of the present invention. When the scope of implementation of the present invention cannot be limited in this way, any simple equivalent changes and modifications made in accordance with the scope of the patent application and the content of the patent specification of the present invention are still Within the scope of the invention patent.

11‧‧‧Drive shaft

111‧‧‧Combination

112‧‧‧ Umbrella teeth

12‧‧‧ Wheel

121‧‧‧Body

122‧‧‧ Shaft

123‧‧‧face

124‧‧‧ Ratchet

13‧‧‧ shaft

2‧‧‧ Umbrella tooth unit

201‧‧‧ the first end

202‧‧‧Second end

21‧‧‧ sleeve

211‧‧‧Inner peripheral surface

212‧‧‧Main section

213‧‧‧ mandrel section

22‧‧‧ Umbrella teeth

23‧‧‧Unidirectional Transmission Coupling Group

230‧‧‧ groove

231‧‧‧ pawl

232‧‧‧Slotted surface

24‧‧‧ mandrel

25‧‧‧Mount

250‧‧‧ installation space

251‧‧‧wall

252‧‧‧Inner peripheral surface

253‧‧‧outer surface

254‧‧‧Screw holes

26‧‧‧Fixed parts

3‧‧‧ dry bearing unit

31‧‧‧First bearing

311‧‧‧block

32‧‧‧Second bearing

4‧‧‧ end cap

d1‧‧‧ diameter of shaft

d2‧‧‧ maximum outer diameter

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a perspective view illustrating a known transmission shaft and a gear; FIG. 2 is an umbrella of the transmission shaft of the present invention A three-dimensional combined view of the first embodiment of one of the tooth devices; FIG. 3 is an exploded perspective view of the first embodiment; FIG. 4 is an incomplete cross-sectional combined view of the first embodiment; An exploded perspective view of a second embodiment of a bevel gear device of a transmission shaft of the invention; FIG. 6 is an incomplete sectional and combined view of one of the second embodiment; and FIG. 7 is a view of a bevel gear device of a transmission shaft of the invention A perspective exploded view of some elements of a third embodiment.

Claims (11)

An umbrella gear device of a transmission shaft is suitable for connecting the transmission shaft and a hub of a bicycle, and the hub is sleeved on a shaft of the bicycle. The umbrella gear device of the transmission shaft includes: an umbrella gear unit with opposite A first end portion and a second end portion, a bevel tooth located on the first end portion and adapted to engage the transmission shaft, and a one-way position located on the second end portion and adapted to unidirectionally drive the hub to rotate A transmission coupling group, the ratio of the diameter of the shaft to the maximum outer diameter of the bevel gear is 0.164 ~ 0.24; and a dry bearing unit is installed in the bevel gear unit and used to make the bevel gear unit rotate smoothly; the hub includes A body portion having an end surface and a shaft portion extending axially from the end surface of the body portion and surrounding the shaft, wherein the bevel gear unit is adapted to be sleeved on the shaft portion, and the dry bearing unit includes a ring A first bearing and a second bearing covering the shaft portion, the first bearing has a stop portion that separates the end surface from the bevel gear unit, and the second bearing separates the bevel gear unit from the shaft portion . The bevel gear device for a transmission shaft according to claim 1, wherein the bevel gear unit includes a sleeve having the first end portion and the second end portion, and the one-way transmission coupling group has a plurality of slotted surfaces or Several ratchet teeth, the sleeve and the umbrella teeth are connected to the groove surface as a whole, or the sleeve and the umbrella teeth are connected to the ratchet teeth as a whole. The bevel gear device of the transmission shaft according to claim 1, wherein the bevel gear unit includes a mandrel having the first end portion, and a mandrel through which the mandrel penetrates and extends and has the second end portion. The mounting seat, the umbrella teeth are formed on the mandrel, and the one-way transmission coupling group is located on the mounting seat. The bevel gear device of a transmission shaft according to claim 3, wherein the mounting seat has a surrounding wall defining an installation space into which the mandrel extends, and the surrounding wall has an inner peripheral surface surrounding the mandrel. And an outer peripheral surface opposite to the inner peripheral surface, and the surrounding wall is formed with at least one screw hole extending from the outer peripheral surface to the inner peripheral surface and communicating with the installation space, the bevel tooth unit further includes at least one via the At least one screw hole is locked into the fixing member for fixing the mounting seat and the mandrel. The bevel gear device of a transmission shaft according to claim 1, wherein the one-way transmission coupling group has a plurality of ratchet teeth. The bevel gear device of a transmission shaft according to claim 1, wherein the one-way transmission coupling group has a plurality of detents. The bevel gear device of the transmission shaft according to claim 1, further comprising an end cover adjacent to the first end portion of the bevel gear unit and used for positioning a relative position between the bevel gear unit and the hub. The bevel gear device of the transmission shaft according to claim 1, wherein a ratio of a diameter of the shaft to a maximum outer diameter of the bevel gear is more preferably 0.188 to 0.237. The bevel gear device of the transmission shaft according to claim 1, wherein the number of teeth of the bevel gear of the bevel gear unit is 14 to 24. The umbrella tooth device of the transmission shaft according to claim 8 or 9, wherein the number of teeth of the umbrella tooth of the umbrella tooth unit is more preferably 15 to 20. The bevel gear device for a transmission shaft according to claim 2, wherein the sleeve includes a main body section having the second end portion, and a mandrel section connected to the main body section and having an outer diameter smaller than the main body section, the The mandrel section has the first end portion, and the umbrella teeth are fixed to the mandrel section.