JPH02231B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a continuously variable transmission for a bicycle, which is suitable as a transmission mounted on the crankshaft of a bicycle.

(Prior art) As this type of continuously variable transmission, for example,
This was disclosed in Publication No. 54-93754.

(Problems to be Solved by the Invention) This continuously variable transmission uses a planetary gear device to increase speed, and the speed increase depends on the ratio of the diameter of the planetary gear and the diameter of the sun gear. Furthermore, the transmission force has a property that the more planetary gears are used, the smaller the pulsation becomes.

However, when all the planet gears and sun gears are arranged on the same plane as in the conventional continuously variable transmission described above, as shown in Fig. 6 a, b, and c, it is necessary to increase the number of planet gears P. , because the diameter of the sun gear S becomes larger, the speed increasing ratio becomes smaller, and if the diameter of the planetary gear P is made larger than the diameter of the sun gear S to increase the speed, the number of planetary gears P becomes smaller. There is a problem in that the pulsation becomes larger as the pulsation becomes smaller.

The present invention has been made to solve the above-mentioned problems, and by providing two stages of planetary gear speed increasers, the diameter of the first stage sun gear can be made relatively large, and the number of planetary gears can be increased. The purpose is to increase the speed, reduce the pulsation of the transmission force, and obtain a sufficient speed increase ratio for the automobile.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, a carrier integrated with a sprocket is rotatably provided in the rear wheel hub of a bicycle, and a plurality of planetary nuclei are rotatably mounted on this carrier. The planetary gears are fitted in each of these planetary cores via one-way clutches so that they can rotate in only one direction, and a circular shape that guides a rocking pin protruding from the eccentric position of the planetary core. A raceway is provided on the rear wheel hub shaft such that the amount of eccentricity thereof can be adjusted freely, and a first sun gear that meshes with each of the planetary gears is rotatably provided on the rear wheel hub shaft.
Multiple planetary gears are rotatably supported on the sun gear,
These planetary gears mesh with internal gears formed on the carrier, and second sun gears meshing with these planetary gears are integrally formed on the rear wheel hub to constitute a continuously variable transmission for a bicycle.

(Function) As described above, in the present invention, by providing the planetary gear speed increaser in two stages, the diameter of the first stage sun gear is made relatively large, and the number of planetary gears used is increased. In addition to reducing the pulsation of the transmission force, it is possible to obtain a sufficient speed increase ratio for the bicycle.

(Example) An example of the present invention will be described below with reference to the drawings. In the figure, 1 (see Figure 7) is the main pipe of the bicycle frame, 2 is the vertical pipe, 3 is the chain stay,
4 is a crankshaft, 5 is a crank gear fixed to the crankshaft 4, 6 is a crank arm that fits on the crankshaft 4, and 7 is a lock nut 8 attached to the chain stay 3.
9 is a rear wheel hub rotatably fitted to the rear wheel hub shaft 7 via bearings 10 and 11; 12 is a spoke;
3 (see FIG. 7) is a rear wheel, 14 is a rear wheel sprocket, and 15 is a chain.

In this embodiment, the chain 15 of the rear wheel hub 9
The side flange 9a is formed into a large diameter disk shape, and the second sun gear 16 is attached to the rear wheel hub 9 at the center thereof.
A first sun gear 17 having a larger diameter than the second sun gear 16 is rotatably provided on the rear wheel hub axle 7 via a bearing 18 on the outside of the second sun gear 16. On the same circumference of the inner surface of the sun gear 17, a plurality of shafts 19 (four in this embodiment) are protruded at positions equally divided around the circumference, and these shafts 19 mesh with the second sun gear 16, respectively. A planetary gear 20 is rotatably provided. Note that 21 is a ring-shaped shaft holding plate provided in an annular recessed portion of the flange 9a of the rear wheel hub 9 to hold the protruding end portion of the shaft 19. Further, this shaft holding plate 21 is connected to the first sun gear 17.
It may be formed integrally with.

Also, the rear wheel hub shaft 7 outside the first sun gear 17
, the center O ₁ of the rear wheel hub shaft 7 as shown in FIG.
A fixed eccentric cam ₂₂ whose center O 2 is eccentric by l ₁ with respect to the fixed eccentric cam 22 is integrally formed, and an eccentric shifter 23 in the form of a hollow disk whose center O ₂ is eccentric by l ₂ with respect to the fixed eccentric cam 22 is operated. A ring-shaped circular raceway 25 is attached to the outer periphery of the eccentric shifter 23 and is fixed integrally with the wire reel 24 and rotatably fitted to the outer periphery of the fixed eccentric cam 22, and has an annular groove 25a formed on one side. It is rotatably fitted via a ball bearing 26.

Then, a disk-shaped case 27 that covers the outer surfaces of the fixed eccentric cam 22, reel 24, eccentric shifter 23, and circular track 25 is fitted onto the rear wheel hub shaft 7 between the fixed eccentric cam 22 and the lock nut 8. and fix it. Note that 28 is an operating wire wound around the reel 24.

Further, a hollow wheel-shaped carrier 29 having the rear wheel sprocket 14 integrally provided on the outer periphery is inserted between the ring-shaped protrusion 9b of the flange 9a of the rear wheel hub 9 and the outer periphery of the case 27, respectively. An internal gear 29a, which is rotatably provided via ball bearings 30 and 31 and formed on the inner peripheral part of this carrier 29, is meshed with the planetary gear 20, and an internal gear 29a is provided on the same circumference of the inner wall plate part of the carrier 29. A plurality of (seven in this embodiment) shafts 32 are provided protrudingly arranged at equal positions on the circumference, and stepped cylindrical planetary nuclei 33 are rotatably fitted onto these shafts 32 via bearings 34, respectively. A ring-shaped planetary gear 36 is fitted onto the outer periphery of each of these planetary cores 33 via a one-way clutch 35 so that it can rotate in only one direction.

The one-way clutch 35 may be of any type, but in this embodiment, as shown in FIG.
a, and a pawl 35b is provided on the outer periphery of the planetary core 33 to engage with the ratchet 35a to prevent rotation in only one direction, and the pawl 35b engages with the ratchet 35a by a spring (not shown). It is energized like this.

Further, a swinging pin 37 parallel to the shaft 32 is protruded at an eccentric position with respect to the shaft 32 on the outer surface of each planetary core 33, and the swinging pin 37 is inserted into the annular groove of the circular raceway 25 through a slider 38. 25a so as to be slidable. Note that 39 is a cover ring that encloses the ball bearing 31 inserted between the case 27 and the carrier 29.

Next, the operation of the apparatus of the present invention constructed as described above will be explained. Figures 1 to 4 show that the eccentricity l (see Figure 2) of the eccentric shifter 23 with respect to the rear wheel hub shaft 7 is l ₁
+l ₂ is the state of maximum eccentricity. And now l ₁ = l ₂
Then, from the state shown in Fig. 2, the operating wire 2
8 to rotate the eccentric shifter 23 approximately 180 degrees, the amount of eccentricity of the circular orbit 25 with respect to the rear hub axle 7 becomes O as shown in FIG. That is, by arbitrarily operating the eccentric shifter 23 within the range shown in FIGS. 4 and 5, the amount of eccentricity of the circular track 23 with respect to the rear wheel hub shaft 7 can be set steplessly to an arbitrary amount. can.

Next, the operation of the continuously variable transmission mechanism is shown in Figures 4 and 5.
The diagram will be explained.

When the crank arm 6 is rotated in the direction of the arrow P in FIG. 7 with eccentricity O in FIG. Rotate in the direction of. Sprocket 14 and carrier 2
As a result, each planetary core 33 and planetary gear 36 are also connected to the carrier 29 via the shaft 32.
rotates with. However, in this case, the swing pin 37 protruding from the planetary core 33 is inserted into the shaft 7 via the slider 38.
Since it rotates while being fitted in the circular orbit 25 concentric with , the center O ₁ of the shaft 7 and the center O ₄ of the shaft 32,
The angle θ between the swing pin 37 and the center O ₅ remains unchanged. Therefore, the planetary core 33 does not rotate at all with respect to the carrier 29.

However, each planetary gear 36 is connected to the first sun gear 1
7, each planetary gear 36 is in mesh with the third sun gear 36 due to the load resistance of the first sun gear 17.
It attempts to rotate clockwise as shown by arrow Q in the figure, but this rotation is caused by the ratchet 35a and pawl 35b.
This is prevented by the action of a one-way clutch 35 consisting of. Therefore, the first sun gear 17 is rotated integrally with the rear wheel sprocket 14 in the same direction as indicated by arrow P in FIG. 5 by the planetary gear 36 which rotates integrally with the carrier 29. Therefore, the transmission ratio of the first sun gear 17 to the sprocket 14 in this case is 1:1.

Therefore, if the first sun gear 17 rotates, the shaft 1
9, the four planetary gears 20 are connected to the arrow R in FIG.
It revolves together with the first sun gear 17 as shown in FIG. In this case, each planetary gear 20 meshes with an internal gear 29a formed on the carrier 29, but at this time, the carrier 29 is also rotating integrally with the first sun gear 17, so the planetary gear 20 cannot rotate on its own axis. First, since the second sun gear 16 meshing with each planetary gear 20 also rotates together with the rear wheel sprocket 14. Therefore, the speed ratio of the second sun gear 16 to the sprocket 14 in this case is also 1:1. When the second sun gear 16 rotates, the rear wheel hub 9 also rotates, so that the rear wheel 13 is driven at the same time. (See Fig. 7) Next, when the eccentric shifter 23 is placed in the eccentric state shown in Figs. As shown, the carrier 29 rotates together with the sprocket 14, and as a result, each planetary core 33 also rotates together with the shaft 32, but in this case, each swing pin 37
The circular track 25 is fitted through the slider 38.
Since the angle θ is eccentric with respect to the rear wheel hub shaft 7, the angle θ changes from θ ₁ to _{θ 7} as shown in FIG. Therefore, each planetary nucleus 33 is a carrier 29
It also rotates from time to time.

In other words, in this case, θ ₁ is the minimum and θ ₄ is the maximum, and between θ ₁ and θ ₄ , there is a relationship of θ ₁ < θ ₂ < θ ₃ < θ ₄ , so between θ ₁ and θ ₄ Since rotation occurs in the planetary gear 36 in the direction of arrow S shown in FIG. The first sun gear 17 is rotated at higher speed than the carrier 29 as shown by arrow T in FIG. In this case, since there are seven planetary gears 36 in this embodiment, gears 36 that are not in the rotation speed increasing range are not accelerated, but due to the action of the one-way clutch 35, among the seven planetary gears 36, At that time, only one planetary gear 36 in the highest speed increasing range is the first sun gear 17.
The remaining six planet gears 36 are rotated by the sun gear 17. That is, at this time, the ratchet 3 of the gear 36
5a will slide and rotate with respect to the pawl 35b.

FIG. 8 shows the speed increasing characteristics of a set of speed increasing planetary gears of the device of the present invention, with the ordinate representing the speed increasing gear ratio and the abscissa representing the rotation angle of the first sun gear 17. .

As can be seen from this, in order to minimize variations in the speed ratio, it is preferable to use a large number of planetary gears 36. Since seven planetary gears 36 are used in this embodiment, the drive angle range of each planetary gear 36 with respect to the first sun gear 17 is about 51 degrees. Therefore, as seen from FIG. 8, in this embodiment, it is possible to obtain rotational driving force with almost no pulsation even during speed increase.

If the first sun gear 17 described above rotates at an increased speed as indicated by the arrow T in FIG.
Since the revolution speed of the planetary gear 20 in the direction of arrow R in the figure is greater than the rotation speed of the internal gear 29a integrated with the carrier 29 in the direction of arrow P, each planetary gear 20
rotates in the direction of arrow U, causing the second sun gear 16 meshing therewith to rotate in the direction of arrow V at a higher speed than the first sun gear 17. Therefore, the speed increasing ratio increases further. This rotation is then transmitted to the rear wheel 13 (see FIG. 7) via the rear wheel hub 9 and spokes 12.

Further, in the above explanation, the case of the minimum speed increasing ratio and the case of the maximum speed increasing ratio have been explained, but by setting the rotational operation amount of the eccentric shifter 23 to an arbitrary amount in the middle, the device of the present invention can be used. According to this, it is obvious that any speed ratio can be obtained steplessly.

(Effect of the invention) Next, the effects of the device of the present invention will be explained.

This type of continuously variable transmission uses a planetary gear system to increase speed, and its speed increase ratio is determined by the ratio of the diameter of the planetary gear to the diameter of the sun gear, and the transmission force is determined by the ratio of the diameter of the planetary gear to the diameter of the sun gear. There is a property that the larger the number of used, the smaller the pulsation becomes.

However, when all the planetary gears and the sun gear are arranged on the same plane as in a known continuously variable transmission, the planetary gear P
If the number of gears is increased, the diameter of the sun gear S becomes larger, so the speed increasing ratio becomes smaller, and if the diameter of the planetary gear P is made larger compared to the diameter of the sun gear S, the speed increasing ratio becomes larger. However, in the continuously variable transmission of the present invention, by providing a speed increasing device using planetary gears in the second stage, the number of planetary gears P decreases and the pulsation increases. By increasing the diameter of the sun gear and increasing the number of planetary gears used, it is possible to reduce the pulsation of the transmission force, and it has the excellent effect of easily obtaining a sufficient speed increase ratio for a bicycle. can get

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the device of the present invention, and FIG.
Front view shown in partial cross section along line A-A in the figure, No. 3
The figure is a front view shown in cross section taken along line B-B in Figure 1;
Figures 4 and 5 are explanatory diagrams of its operation, Figures 6a, b, and c are explanatory diagrams showing various combinations of planetary gears and sun gears, and Figure 7 is a side view of a bicycle attached to the device of the present invention. , FIG. 8 is a speed increase characteristic diagram of the device of the present invention. 4...Crankshaft, 5...Crank gear, 6...
... Crank arm, 7 ... Rear wheel hub axle, 9 ... Rear wheel hub, 13 ... Rear wheel, 14 ... Rear wheel sprocket, 15 ... Chain, 16 ... Second sun gear,
17...First sun gear, 20...Planetary gear, 22
... Fixed eccentric cam, 23 ... Eccentric shifter, 24
... Reel, 25 ... Circular orbit, 27 ... Case, 28 ... Operation wire, 29 ... Carrier,
32... shaft, 33... planetary nucleus, 35... one-way clutch, 36... planetary gear, 37... rocking pin,
38... Slider.

Claims (1)

[Claims] 1 A rotatable carrier integrated with a sprocket is provided on the rear wheel hub of a bicycle, a plurality of planetary nuclei are rotatably supported on this carrier, and a planetary gear is connected to each of these planetary nuclei in one direction via a one-way clutch. A circular track for guiding a swing pin protruding from an eccentric position of the planetary core is provided so that the amount of eccentricity can be freely adjusted with respect to the rear wheel hub shaft, and meshes with each of the planetary gears. A first sun gear is rotatably provided on the rear wheel hub axle, a plurality of planetary gears are rotatably supported on the first sun gear, and these planetary gears are meshed with an internal gear formed on the carrier. A continuously variable transmission device for a bicycle, characterized in that a second sun gear meshing with each of these planetary gears is integrally formed on a rear wheel hub.