JPH0714720B2 - Continuously variable transmission for bicycles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a continuously variable transmission for a bicycle, which is mounted on a bicycle and is capable of continuously shifting in accordance with the amount of eccentricity.

[Prior Art] Generally, a transmission of this type is configured to continuously transmit a speed change by a pawl color feed that meshes with a ratchet gear. This is because when a ratchet pawl sequentially enters a drive range in an eccentric state, Is added, or due to a difference in speed between a plurality of ratchet pawls in the drive range, a gap is generated between the tooth tips of the ratchet claws, which causes rattling of transmission power, so-called pulsation.

For this reason, Japanese Patent Laid-Open No. 61-184192 has been proposed to reduce pulsation. This is to reduce the pulsation of power transmission by providing a plurality of sets of ratchet gears and ratchet pawls in parallel to greatly increase the number of ratchet pawls.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, since it is necessary to provide a plurality of sets of ratchet gears and ratchet pawls in parallel, there is a problem in terms of handling and cost due to the large size and complicated structure. It was

Therefore, an object of the present invention is to provide a continuously variable transmission for a bicycle, the structure of which is simplified and the pulsation of power transmission can be prevented.

[Means for Solving the Problems] The present invention relates to an input side rotating member, an output side rotating member such as a ratchet gear to which rotation is transmitted by meshing with the input side rotating member, and a circumference of the input side rotating member. A plurality of rows arranged in the same direction, each of which is provided with a ratchet pawl rotatably provided on its base side via a spring wound around a pivot provided on the input side rotation member, and the input side rotation member and the ratchet gear. In a continuously variable transmission for a bicycle in which and are relatively eccentrically moved to change gears, on the base side of the ratchet pawl,
A long hole for loosely inserting the pivot shaft is formed along the meshing direction with the ratchet gear, and a cushioning means for urging the ratchet pawl in the meshing direction by elastic restoring force at the time of rotation transmission is provided. .

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 11 show the first embodiment, and FIGS.
In the figure, 1 is a main pipe of a bicycle frame, 2 is a vertical pipe, 3 is a chain stay, 4 is a hanger rag formed integrally with the bicycle frame, 5 is a clamp shaft, and 6 is fixed to a crank shaft 5 thereof through a lock nut 7. Crank arm, 8 is rear wheel, 9 is rear wheel hub axle, 10 is rear wheel sprocket, and 11 is chain.

Reference numeral 12 denotes a hollow cylindrical case that is an input side rotating member. The hollow cylindrical case 12 has its center portion fixed to the crankshaft 5 by the lock nut 7, and the crank arm 6 is integrated with the hollow cylindrical case 12. Is formed in. In this case, the crank arm 6 and the hollow cylindrical case 12 may be formed separately, and the hollow cylindrical case 12 may be fixed to the crankshaft 5 via the crank arm 6. 13 is a plurality of teeth 14
Ratchet pawl having a hollow cylindrical case 12
And a lid 12A of the case 12 in the cylindrical portion 15
Ratchet pawls 13 are arranged in parallel at equal intervals, and each ratchet pawl 13 is rotatably provided by a pivot 16 at a base end, and a spring wound around the pivot 16 provided in a hollow cylindrical case 12.
It is urged toward the center of the hollow cylindrical case 12 by 17. In addition, as shown in FIGS.
Reference numeral 16 is a long hole 13T provided along the length direction of each ratchet pawl 13 which is a direction of meshing with a ratchet gear described later.
The support shaft 16A is provided in the hollow cylindrical case 12 positioned behind the ratchet pawl 13 while being loosely inserted in the support shaft 1.
A coiled spring 17A for urging the base end of the ratchet pawl 13 forward along the elongated hole 13T, which is the direction of engagement with the ratchet gear, is wound around 6A.
_Make up _one . Further, a receiving surface 18 having no tooth portion 14 is formed at the end of the tooth portion 14 of each ratchet pawl 13 on the case 12 side,
This receiving surface 18 is slidably guided on the peripheral surface of a disk-shaped guide portion 19 having a circular orbit 19A having the same diameter as a ratchet gear described later, which is integrally formed on the inner surface of the hollow cylindrical case 12. ing. Reference numeral 20 denotes a retaining ring of a bearing 21 that rotatably supports the crankshaft 5 in the hanger lug 4, and a retaining ring nut 22 is screwed to the retaining ring 20. 23 is the end of the hanger lug 4 and a hanger stop nut
It is a disc-shaped fixed cam that is fixedly sandwiched between 22 and is arranged so that an eccentric cam 25, which is an eccentric moving body, can rotate along an annular flange portion 24 formed on the peripheral edge of the fixed cam 23. Has been done. The eccentric cam 25 has a cam presser 26A at one end.
A wire reel 26 provided via the above is rotatably fitted to the annular flange portion 24. Also, the eccentric cam
Numeral 25 is adapted to rotate while being guided by the fixed cam 23 about an obliquely lower position on the rear side of the center A of the crankshaft 5 as a center B, and an arc surface 27 centered on the point B.
Is formed in the eccentric cam 25.
The crankshaft 5 is inserted through 28. 29 is the eccentric cam
A ratchet gear serving as an output side rotating member rotatably provided on a circular cam surface 30 formed on the outer periphery of 25 via a bearing 31, and a cam holder 26 of the ratchet gear 29.
A sprocket 32 is screwed and fixed to the end portion on the A side. 33
Is a retaining ring of the bearing 31, 34 is a ratchet gear
Collar between the teeth 29A of 29 and the sprocket 32, 36
Is a circular restricting portion that guides each ratchet pawl 13.

An eccentric amount adjusting mechanism 37 is connected to the cam retainer 26A. In this embodiment, in the eccentricity adjusting mechanism 37, a wire reel 40 having a manual operation lever 39 is rotatably supported by a disc-shaped receiver 38 fixed to the upper side of the main pipe 1, and the wire reel 40 One end of the pair of wires 41, 42 is fixed above and below via the pins 43, 44, and the other end of the wires 41, 42 is fixed above and below the rear side of the wire reel 26 via the pins 43A, 44A. The pins 43, 44, 43A, 44A are fitted and fixed in the holes 45 of the wire reels 26, 40 with the wires 41, 42 fixed.

Further, the receiving surface 18 of the ratchet pawl 13 and the disc-shaped guide portion
The structure of the disc-shaped guide portion 19 will be described.
Has a circular orbit 19A having the same diameter as the ratchet gear 29 and is formed integrally with the inner surface of the hollow cylindrical case 12 concentrically with the crankshaft 5 or by fastening with screws or the like. On the other hand, the ratchet pawl 13 has a receiving surface 18 formed at the inner surface side end of the hollow cylindrical case 12 over the entire length, and the receiving surface 18 is formed.
Reference numeral 18 has a front receiving surface 18A extending up to the front of the gear 14 of the ratchet pawl 13.

Further, at the end portion of the ratchet gear 29 on the side of the disc-shaped guide portion 19, a disc regulating portion 36 made of a ring body having substantially the same diameter as that of the ratchet gear 29 is integrally and concentrically fixed. When the ratchet pawl 13 therein engages with the ratchet gear 29, the receiving surface 18 of the ratchet pawl 13 has the circular restricting portion 36.
Engaged with the ratchet pawl 13 gear 14 and ratchet gear
It is formed so as to regulate the meshing depth of the 29 teeth 29A.

Next, the operation of the apparatus of this embodiment configured as described above will be described. First, when the crank arm 6, the crankshaft 5, and the hollow cylindrical case 12 are integrally rotated via the crank pedal 46, the ratchet gear 29 is rotated via the ratchet pawl 13 mounted on the hollow cylindrical case 12, The sprocket 32 rotates integrally with the ratchet gear 29, and the rotation of the sprocket 32 is transmitted to the rear wheel 8 by the chain 11 via the rear wheel sprocket 10.

FIGS. 7A and 7B show the case where the ratchet gear 29 is located at the center of the hollow cylindrical case 12 and the eccentricity is o,
At this time, the ratchet gear 29 and the disc-shaped guide portion 19 are concentric with each other, and all the ratchet pawls 13 are engaged with the ratchet gear 29, and the receiving surface 18 of the ratchet pawl 13 and the disc on the hollow cylindrical case 12 side. It is held at a constant inclination angle by sliding contact with the guide portion 19. As a result, the gear ratio between the crankshaft 5 and the sprocket 32 is 1: 1. From this state, lever 39
When the wire reel 40 is moved forward by manual operation, the wire reel 40 rotates clockwise through the disc-shaped receiver 38, and accordingly, the pair of wires 41, 42 and the pins 43, 44, 43A, 44A. The connected wire reel 26 rotates clockwise along the annular flange portion 24 of the fixed cam 23. . As a result, the eccentric cam 25 rotates integrally with the wire reel 26 about the point B,
As a result, the ratchet gear 29 provided concentrically with the eccentric cam 25 is located at the center of the hollow cylindrical case 12, that is, the crankshaft 5.
Move eccentrically to. In this case, the eccentric cam 25
The arcuate surface 27 of 28 and the crankshaft 5 are guided in sliding contact with each other, and the movement locus of the center A of the crankshaft 5 virtually obtained by the rotation of the eccentric cam 25 is an arc from point A to point A '. It becomes C.

FIGS. 9 (A) and 9 (B) show the case where the eccentric amount of the hollow cylindrical case 12 with respect to the ratchet gear 29 is in the maximum eccentric state, and at this time, the eccentric cam 25 has a center hole 28 centered at the point B.
Ratchet gear 29 that rotates clockwise to the position where the left end of the contact with the crankshaft 5 and moves integrally with the eccentric cam 25
Pushes the two ratchet pawls 13A, 13B in the drive range D. As a result, the ratchet pawls 13A, 13B mesh with the ratchet gear 29 by the biasing force of the spring 17, and the other ratchet pawls 13 are separated from the ratchet gear 29 by the sliding contact between the receiving surface 18 and the disc-shaped guide portion 19. Will be guided in.

The ratchet pawls 13A, 13B in the drive range D have the maximum speedup rate, so the ratchet gear 29 is rotated by the ratchet pawls 13A, 13B at an increased speed, and the other ratchet pawls 13 are rotated.
Disengages from ratchet gear 29. Also ratchet claws
The ratchet pawls 13 that are sequentially accelerated such that the ratchet pawls 13 adjacent to 13A and 13B move out of the drive range D and the adjacent ratchet pawls 13 enter the drive range D to accelerate the ratchet gear 29.
A and 13B take turns.

FIGS. 8 (A) and 8 (B) show the case where the eccentricity of the hollow cylindrical case 12 with respect to the ratchet gear 29 is in the middle of the maximum stage from o. At this time, the eccentric cam 25 is centered on the point B. The ratchet claws 13A, 13B, 13C in the drive range D mesh with the ratchet gear 29 so that the other ratchet claws 13 can rotate. All are out of ratchet gear 29. In this case, the inclination angles of the three ratchet pawls 13A, 13B, 13C are smaller than the inclination angles of the ratchet pawls 13A, 13B shown in FIGS. 7 (A) and (B). That is, a gear is virtually formed in the hollow cylindrical case 12 by the ratchet pawls 13A, 13B, 13C in the driving range D, and the diameter of this gear is changed by the operation of the lever 39 to rotate the eccentric cam 25. Ratchet claws performed by 13
The gear ratio (speed increase ratio) of the ratchet gear 29 changes continuously according to the change of the inclination angles of A, 13B, and 13C.

At the time of eccentricity shown in FIGS. 8 and 9, the drive range D
The ratchet pawls 13A, 13B, 13C in the inside move rearward while accumulating a restoring force in the spring 17A by the meshing load with the ratchet gear 29, and the pivot 16 is positioned in the front side of the slot 13T. On the other hand, since the ratchet pawls 13A, 13B, 13C outside the driving range D are not subjected to the meshing load with the ratchet gear 29, the ratchet pawls 13A, 13B, 13C are in the state of being moved forward by the bias of the spring 17A, and the pivot 16 Is located behind the slot 13T.
Then, the ratchet pawls 13A, 13B, 13C in the drive range D are sequentially replaced with the rotation of the hollow cylindrical case 12 which is the input side rotating member, but the ratchet pawl 13 enters the drive range D for the first time as the ratchet gear 29. When meshed, the meshing load may be instantaneously transmitted to the hollow cylindrical case 12 and may be transmitted to the pedal side as pulsation. However, in the present embodiment, the base side of the ratchet pawl 13 is formed with a long hole 13T into which the pivot 16 is loosely inserted along the meshing direction with the ratchet gear 29, and the ratchet is elastically restored during rotation transmission. nail
Since the cushioning means SA ₁ for urging 13 in the meshing direction is provided and the cushioning means SA ₁ is constituted by the spring 17A, the meshing load is not directly transmitted to the hollow cylindrical case 12 and is a long hole.
It is absorbed by the spring 17A via 13T, and thus the pulsation of power transmission is well prevented. Further, from the speed difference between the plurality of ratchet pawls 13A, 13B, 13C in the drive range D, each ratchet pawl 13A, 1
A gap is created between the tooth tips of 3B and 13C, which may cause a shock during rotation. However, the buffer means SA
_{By 1} , the gap is absorbed by the movement of the ratchet pawls 13A, 13B, 13C through the long hole 13T, and the shock is satisfactorily prevented. Also, each ratchet claw 13A, 13B, 13C
Is urged by the spring 17A in the circumferential direction of the ratchet gear 29, so that the problem of the meshing state with the ratchet gear 29 is elastically eliminated.

During the eccentric movement, the engagement / disengagement state of the ratchet pawl 13 and the ratchet gear 29 is as shown in FIGS. 7 (A), 8 (A), and 9 (A). The ratchet pawls 13A, 13B, 13C in the area D are in a state in which the receiving surface 18 and the circular orbit 19A are disengaged and the tooth portions 14 of the ratchet pawls 13A, 13B, 13C are in mesh with the ratchet gear 29. Ratchet claw
The ratchet claw 13 is disengaged from the ratchet gear 29 in a state where the receiving surface 18 and the circular orbit 19A are engaged and held at a substantially constant inclination angle. On the other hand, when the ratchet pawl 13 comes out of the driving range D, the tip portion 18A of the ratchet pawl 13 engages with the circular orbit 19A prior to the disengagement of the tooth portion 14 of the ratchet pawl 13 and the ratchet gear 29 from the tip of the ratchet pawl 13. Guides the ratchet gear 29 in the tangential direction of the ratchet gear 29, and when it enters the drive range D, the ratchet pawl 13 is guided in the tangential direction of the ratchet gear 29 with the front receiving surface 18A engaged with the circular track 19A. While meshing smoothly.

Further, as shown in FIG. 5, when the ratchet pawl 13 is disengaged from the receiving surface 18 and the circular track 19A, the tooth portion 14 of the ratchet pawl 13 and the tooth 29A of the ratchet gear 29 are engaged. The receiving surface 18 is engaged with the circular restricting portion 36 to restrict the engagement depth between the teeth 14 and 29A. That is, in the meshing state of both teeth 14 and 29A, an appropriate clearance is always formed between the crest of the tooth 14 and the trough of the tooth 29A and the crest of the valley 29A of the tooth 14 so that the teeth 14 and 29A are mutually separated. Can effectively suppress the friction.

FIGS. 12 to 15 show a second embodiment, and the description will be made by using the same reference numerals for the same parts as those in the above embodiment.
The pivot 16 is loosely inserted in the elongated hole 13T of the outer cylinder 16B, and the outer cylinder 16B is externally mounted on the pivot 16, and the outer peripheral surface of the outer cylinder 16B and the elongated hole 13T.
An elastic body 17B made of rubber or the like is fitted between the inner peripheral surface of the
The elastic body 17B constitutes the buffer means SA ₂ . Then, the ratchet pawl 13 enters the driving range D and a meshing load with the ratchet gear 29 is applied for the first time, and at the time of this rotation transmission, the ratchet pawl 13 moves rearward while accumulating a restoring force in the elastic body 17B, and the meshing load. Is absorbed by the elastic body 17B. Also, each ratchet pawl 13A, 13B,
Similarly, the gap between the tooth tips of 13C is also absorbed by the elastic body 17B, and the pulsation of power transmission is satisfactorily prevented.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, it goes without saying that the transmission can be applied to various types having a ratchet pawl.

[Advantages of the Invention] According to the present invention, an input side rotating member, an output side rotating member such as a ratchet gear to which rotation is transmitted by meshing with the input side rotating member, and a plurality of rows arranged in the circumferential direction of the input side rotating member. And a ratchet pawl rotatably provided on each base side via a spring wound around a pivot provided on the input side rotation member, and the input side rotation member and the ratchet gear are relatively provided. In a continuously variable transmission for a bicycle that is eccentrically moved to change gears, on the base side of the ratchet pawl,
A long hole for loosely inserting the pivot is formed along the meshing direction with the ratchet gear, and buffer means for urging the ratchet pawl in the meshing direction by elastic restoring force during transmission of rotation is provided. It is possible to provide a continuously variable transmission for a bicycle in which the pulsation is absorbed by the buffering means, the structure thereof is simplified, and the pulsation of power transmission can be satisfactorily prevented.

[Brief description of drawings]

1 to 11 show a first embodiment of the present invention, in which FIG. 1 is an overall longitudinal sectional view, FIG. 2 is a perspective view, FIG. 3 is an exploded perspective view, and FIGS. 6 is a sectional view showing the guide state of the ratchet pawl, FIG. 6 is a perspective view of the ratchet pawl, FIGS. 7 (A) and (B) are sectional views showing a state of eccentricity o, and FIGS. 8 (A) and (B) are eccentricity amounts.
9A and 9B are sectional views showing the state of maximum eccentricity e, FIG. 10 is a perspective view showing an eccentricity adjusting mechanism, and FIG. State of use, Figures 12 to 15
FIG. 12 shows a second embodiment, FIG. 12 is a longitudinal sectional view, FIG. 13 is a perspective view, FIG. 14 is a sectional view of a ratchet pawl, and FIG. 15 is a sectional view of essential parts. 12 …… Input side rotating member 13 …… Ratchet claw 13T …… Long hole 16 …… Pivot 17 …… Spring 29 …… Output side rotating member SA ₁ , SA ₂ …… Cushioning means

Claims (1)

[Claims] 1. An input side rotating member, an output side rotating member such as a ratchet gear to which rotation is transmitted by meshing with the input side rotating member, and a plurality of rows arranged in the circumferential direction of the input side rotating member. A ratchet pawl whose base side is rotatably provided via a spring wound around a pivot provided on the input side rotating member, and relatively eccentrically moves the input side rotating member and the ratchet gear. In a continuously variable transmission for a bicycle that is capable of shifting, a long hole is formed on the base side of the ratchet pawl so as to loosely insert the pivot along the meshing direction with the ratchet gear, and is elastic during rotation transmission. A continuously variable transmission for a bicycle, comprising a cushioning means for urging the ratchet pawl in the meshing direction by a restoring force.