JPH0774026B2 - 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 feed that meshes with a ratchet gear. This is because when the ratchet pawl sequentially enters the drive range in an eccentric state, the load is increased. The rattling of the power transmission causes so-called pulsation due to a cause such as a gap between the tooth tips of the ratchet claws in the driving range due to the speed difference between the ratchet claws.

This will be explained with reference to FIGS. 14 to 18.
As shown in FIG. 15, 6 in the circumference of the hollow cylindrical case A which is an input side rotating member that rotates integrally with a crank (not shown).
In the transmission in which the individual ratchet pawls B are provided, and the ratchet pawl B is meshed with the ratchet gear C that is the output side rotation member, the relation between the ratchet pawl support shaft position and the gear ratio at the time of maximum gear shifting is the 16th. It looks like the graph in the figure,
The ratchet pawl B has a hollow cylindrical case A with a rotation angle of 60 °.
Drive in sequence and the driving range is 60 °
Is.

In the graph of FIG. 16, the ratchet pawl support shaft position is based on the eccentric direction of the ratchet gear C with respect to the center of the hollow cylindrical case A (0 °), and the rotation advancing direction (+) is the opposite. It shows the relationship between the ratchet pawl support shaft position and the gear ratio in the case of (-). Ratchet claw B
When the drive range is expressed by the ratchet pawl shaft position, the relationship between the crank rotation angle and the gear ratio when the drive range is -20 ° to 40 ° is as shown in the graph in Fig. 17. , The above relationship when the driving range is -80 ° to -20 ° is as shown in the graph of Fig. 18, and the more the driving range shifts to the (+) side, the larger the pulsation becomes The pulsation is small.

The conventional transmission has a drive range of about −44 ° to 16 °. This is from the position of the ratchet pawl B _{1 to} the position of the ratchet pawl B in FIG.

In FIG. 15, the ratchet gear C is driven by the ratchet pawl B.
From the ratchet claw B ₁ to the state immediately after,
A gap t is formed between the tooth tips of the ratchet pawl B ₂ and the ratchet gear C that are meshed next. To drive the ratchet pawl B ₂ and the ratchet gear C meshed to include, but shall disappear gap t, the position of FIG. 15, towards the ratchet gear C is compared with the ratchet pawl B _2, Since the relative speed is high, the gap does not become small. However, when the crank rotates and the ratchet pawl B ₂ rotates from the (-) side toward the (+) side, the ratchet gear C and the ratchet pawl are
The difference in relative speed with B ₂ becomes smaller, and finally reverses, closing the gap t, and when the ratchet pawl B ₂ reaches the position of the ratchet pawl B ₁ , the gap t disappears and the drive state is established. Therefore, there is a speed difference between the ratchet pawls B ₁ and B ₂ to be driven, so that pulsation occurs.

The following measures can be considered to prevent such pulsation.

The first is to reduce the tooth module of each ratchet pawl to the 15th
The gap t in the figure is made small and the drive range is set to the (-) side as much as possible. Secondly, the number of ratchet pawls is increased to narrow the drive range. However, in the case of the first measure, it is difficult to reduce the size of the module due to the inconvenience such as the strength of the tooth portion or the occurrence of tooth jump, and in the case of the second measure, the drive range is on the (+) side. There is no effect unless an additional ratchet claw is added, and the device grows in size.

Then, a second measure for preventing pulsation is proposed in Japanese Patent Application Laid-Open No. 61-184192. This is to reduce the pulsation of power transmission by arranging a plurality of sets of ratchet gears and ratchet pawls side by side in the axial direction of the crankshaft to significantly increase the number of ratchet pawls.

[Problems to be Solved by the Invention] In the above-mentioned conventional technology, since a plurality of ratchet gears and ratchet pawls are arranged side by side in the axial direction of the crankshaft, the structure is large and the structure is complicated, which causes problems in handling and cost. Had.

Therefore, the present invention focuses on the first measure, makes it possible to shift the drive range to the (-) side as much as possible without reducing the module of the tooth portion of the ratchet pawl, simplify the configuration, and pulsate the power transmission. An object of the present invention is to provide a continuously variable transmission for a bicycle that can prevent the above-mentioned problems.

[Means for Solving the Problems] The present invention relates to an input side rotation member, and a plurality of ratchet pawls arranged in the circumferential direction of the input side rotation member, each base side being rotatably provided by one pivotal support. A bicycle having an output side rotating member having a ratchet gear to which rotation is transmitted by meshing with the ratchet pawl, wherein the input side rotating member and the ratchet gear are relatively eccentrically moved to shift gears. In the continuously variable transmission for use, the ratchet pawls are rotatably arranged side by side on the one pivotal support portion in a plurality of sets, and each ratchet pawl is provided with a continuous tooth portion to form the set. It is configured by arranging the tooth portions of the ratchet claw that are continuous with each other with a phase shift.

[Operation] With the above configuration, it is possible to reduce the gap between the tooth portion of the ratchet pawl and the tooth portion of the ratchet gear that enter the driving range without reducing the module of the tooth portion, and the pulsation of the transmission force generated by this gap can be reduced. To be prevented.

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

1 to 11, 1 is a main pipe of a bicycle frame, 2 is a vertical pipe, 3 is a chain stay, 4 is a hanger rag integrally formed with the bicycle frame, 5 is a crank shaft, and 6 is a crank shaft 5 thereof. A crank arm fixed via a lock nut 7, 8 is a rear wheel, 9 is a rear wheel hub axle, 10 is a rear wheel sprocket, and 11 is a 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 ratchet pawl, which is the hollow cylindrical case 12 and this case
Six sets are arranged side by side at equal intervals in the circumferential direction in the cylindrical portion 14 composed of the 12 lids 12A, and two sets are arranged in parallel in the circumferential direction, and each set has the two ratchet pawls 13 and 13A overlapped with each other. Each of the two ratchet pawls 13 and 13A of each set is provided with a plurality of continuous tooth portions 16 and 16A, respectively, which are rotatably arranged side by side by a common pivot shaft 15 which is a pivotal support portion at the base end. Is provided, and the tooth portions 16 and 16A of the ratchet pawls 13 and 13A forming this set are 1 / one of one tooth.
It is formed by shifting the phase by 2 pitches. In this case, the pivot 15 is fitted to the cap-shaped receiving metal 15A at both ends, and the receiving metal 15A is inserted into the hollow cylindrical case 12 and the lid 12A.
It is fitted in the hole 15B provided in the. Ratchet claw 1
A washer 15C is interposed between 3 and 13A. Further, each ratchet pawl 13, 13A has a tooth 16 and a cushioning member 16 such as rubber on the tooth 16A.
B is provided, and a buffer member 15D is provided at the pivotal support.
In this case, one of the cushioning members 16B is provided by the applicant in Japanese Patent Application No. 62-216040.
Of the other cushioning member 15
D has the same structure as that proposed by the applicant in Japanese Patent Application No. 62-217434. Further, a leaf spring 17 is fixed to the cylindrical portion 14, and one ratchet pawl 13 of each of the sets is connected to the other leaf piece 17B by one spring piece 17A formed on the leaf spring 17.
The other ratchet pawls 13A are biased toward the center of the hollow cylindrical case 12 by the. An engaging portion 18 is formed at the base ends of the ratchet pawl 13 and the ratchet pawl 13A, and the engaging portion 18 engages with the inner peripheral surface 19 of the hollow cylindrical case 12 so that the ratchet pawls 13 and 13A are formed. Are configured to be guided in a state in which they are stopped at the same inclination angle.

Reference numeral 20 is a stop ring of a bearing 21 that rotatably supports the crankshaft 5 in the hanger rag 4, and this stop ring
A hanger stop nut 22 is screwed onto the 20. Reference numeral 23 denotes a disc-shaped fixed cam integrally fixed to the stop ring 20, and an annular flange portion formed on the peripheral edge of the fixed cam 23.
An eccentric cam 25, which is an eccentric moving body, is provided so as to be rotatable along 24. A wire reel 26 provided on one end of the eccentric cam 25 via a cam retainer 26A is rotatably fitted to the annular flange portion 24. Further, the eccentric cam 25 is configured to rotate while being guided by the fixed cam 23 about a diagonally lower position rearward of the center A of the crankshaft 5 as a center B, and an arc centered on the point B. A center hole 28 having a surface 27 is formed in the eccentric cam 25, and the crankshaft 5 is inserted through the center hole 28. Reference numeral 29 denotes a ratchet gear rotatably provided on a circular cam surface 30 formed on the outer circumference of the eccentric cam 25 via a bearing 31, and a sprocket 32 is provided at an end of the ratchet gear 29 on the cam retainer 26A side. Are screwed and fixed, and the ratchet gear 29, the sprocket 32, and the like constitute an output side rotation member. 33 is a retaining ring of the bearing 31, 34 is a collar interposed between the tooth portion 29A of the ratchet gear 29 and the sprocket 32, and 36 and 36A are the hollow cylindrical case 12 side and the sprocket.
This is a dust intrusion prevention plate provided on 32.

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.

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 pawls 13 and 13A mounted on the hollow cylindrical case 12. Then, 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. 6A and 6B 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, one of the ratchet gear 29 and the ratchet pawls 13 and 13A is in mesh with the ratchet gear 29, and the engaging portion 18 of the ratchet pawls 13 and 13A and the inner peripheral surface 19 of the hollow cylindrical case 12 are in contact with each other.
It is held at a constant inclination angle by sliding contact with. As a result, the gear ratio between the crankshaft 5 and the sprocket 32 is 1: 1. When the lever 39 is manually moved forward from this state, the wire reel 40 is rotated clockwise through the disc-shaped receiver 38, and accordingly, the pair of wires 41, 42 and the pins 43, 4 are moved.
The wire reel 26 connected through 4,43A, 44A 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, and as a result, the ratchet gear 29 provided concentrically with the eccentric cam 25 moves to the center of the hollow cylindrical case 12, that is, the crankshaft. Move eccentrically with respect to 5. In this case, the eccentric cam 25 includes the circular arc surface 27 of the center hole 28 and the crankshaft 5.
And is 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 C from the point A to the point A '.

FIGS. 7 (A) and 7 (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. 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 sets of ratchet pawls 13DR and 13ADR in the drive range D. As a result, the ratchet pawls 13DR, 13ADR mesh with the ratchet gear 29 by the biasing force of the spring 17, and the other ratchet pawls 13, 13A are separated from the ratchet gear 29 by the sliding contact between the engaging portion 18 and the inner peripheral surface 19. You will be guided in the state.

Since the ratchet pawls 13DR and 13ADR in the drive range D have the maximum speed increasing rate, the ratchet gear 29 is rotated by the ratchet pawls 13DR and 13ADR to increase speed, and the other ratchet pawls 13 are disengaged from the ratchet gear 29. Further, the ratchet pawls 13DR and 13ADR are disengaged from the drive range D, and the adjacent ratchet pawl 13 enters the drive range D to move the ratchet gear 29.
The ratchet pawls 13DR and 13ADR, which are sequentially speed-up-driven such as speed-up driving, alternate.

That is, a gear is virtually formed in the hollow cylindrical case 12 by the ratchet pawls 13DR and 13ADR in the drive range D,
The diameter of this gear changes in accordance with the change in the inclination angle of the ratchet pawls 13DR, 13ADR that is caused as the eccentric cam 25 rotates by operating the lever 39, and the gear ratio (speed increase ratio) of the ratchet gear 29 changes. Change steplessly.

At the time of eccentricity shown in FIG. 7, two ratchet pawls 13 and 13A rotatable about a pivot 15 which is one pivot.
As one set, and the continuous tooth portions 16 and 16A are 1/2 of one tooth.
Since the phase is shifted by each pitch,
As shown in FIG. 9, one of the two sets of ratchet pawls 13DR and 13ADR in the drive range D is the tooth portion of the ratchet pawl 13DR.
When the drive is such that 16 and the tooth portion 29A of the ratchet gear 29 are normally meshed, the other set to be driven next is the gap t / between the tooth portion 16A of the ratchet pawl 13ADR and the tooth portion 29A of the ratchet gear 29. It is 2.

Therefore, the drive range is from −20 ° to 40 ° to −53 ° to 7 °
The drive range D shifts to the (−) side up to about °, and the pulsation is improved accordingly. Thus, in the above embodiment,
Rather than arranging multiple sets of ratchet gears and circumferential ratchet pawls in the axial direction of the crankshaft as in the past,
The structure is such that, for example, six ratchet pawls 13 and 13A are arranged in the circumferential direction in the same manner as in the conventional case, with two ratchet pawls 13 and 13A with the phase shift of the continuous tooth portions 16 and 16A as one set. Is simple and compact, and since it is not necessary to make the module of the tooth portions 16 and 16A small, it is possible to obtain a sufficient strength of the tooth portions 16 and 16A and to obtain a stable meshing operation without worrying about tooth skipping.

FIG. 12 and FIG. 13 show a second embodiment of the present invention. Explaining the same parts as those in the above embodiment, the description will be omitted. 51 is a chain stay of a bicycle frame, and 52 is a rear wheel hub axle.
Is fixed by a lock nut 53 via a receiving plate 51A, a rear wheel hub 54 is rotatably fitted to a rear wheel hub shaft 52 via a bearing (not shown), and a spoke is attached to the rear wheel hub 54.
55 are connected. 56 is an arm whose one end is rotatably connected to the inside of one of the chain stays 51 by a pivoting portion 57, and a plurality of discs 58 are provided with screws 59 on the inner surface of the arm 56.
It is fixed by. 60 is a bearing on the outer circumference of the disk 58
A hollow cylindrical case that is an input side rotating member rotatably provided via 61, and a sprocket 62 is concentrically and integrally screwed to the outer periphery of the hollow cylindrical case 60. The arm 56 and the disk 58 are provided with elongated holes 63 extending from the center of the disk 58 to the vicinity of the lower end, respectively.
The rear wheel hub shaft 52 is inserted through 63, the arm 56 and the chain stay 51 are connected by a tension spring 64,
The arm 56 is biased upward, and the hub shaft 52 side is held in a state of being locked to the upper end of the elongated hole 63. Long hole 63 in this case
The maximum eccentric position is maintained by the engagement of the lower end of the rear wheel hub shaft 52 side with the rear wheel hub shaft 52, and the maximum eccentricity is maintained by the engagement of the upper end of the elongated hole 63 with the rear wheel hub shaft 52 side. 65 is a ratchet pawl having a plurality of continuous teeth 66, 65A is one of the teeth 66 and one tooth
A ratchet pawl having a plurality of continuous tooth portions 66A with a 1/2 pitch phase shift. These two ratchet pawls 65, 65A
As one set, a plurality of sets of ratchet pawls 65, 65A are arranged in parallel on the inner surface side inside the cylindrical portion 60A of the hollow cylindrical case 60,
Each set of ratchet pawls 65, 65A is rotatably provided by a pivot 67 at the base end and a collar 67A mounted on the pivot 67, and is attached toward the center of the hollow cylindrical case 60 by a spring 68 wound around the pivot 67. It is energized.

On the outside of the chain stay 51, the receiving plate 51A is screw 71.
Is fixed by the rear wheel hub shaft 5 on the inner surface side of the receiving plate 51A.
An outer cylinder 72 that covers 2 is integrally formed, and an inner cylinder 73 is provided inside the outer cylinder 72.

Next, the operation of the apparatus of this embodiment configured as described above will be described. First, as shown in FIG. 13, the crank gear 75 rotates via the crank pedal 74, and the rotation of the crank gear 75 is transmitted to the sprocket 62 by the chain 76. The sprocket 62 rotates integrally with the hollow cylindrical case 60 serving as an input side rotating member via a bearing 61, and a ratchet gear that constitutes an output side rotating member via ratchet pawls 65, 65A mounted on the hollow cylindrical case 60. The 77 is rotated, and the rotation is transmitted from the ratchet gear 77 to the rear wheel hub 54. And
Ratchet pawl 65, 65A that naturally applies a large force to the pedal when starting, climbing uphill or driving on a rough road, increasing the tension of the chain 76 and propelling the ratchet gear 77
A large load is applied to the ratchet claws 65, 65A depending on the magnitude of this load with the pivot 67 as the fulcrum.
Bite to the side, which results in ratchet pawls 65,6
5A rises, and this action causes arm 56
Moves downward against the force of the spring 64 with the pivot portion 57 serving as a fulcrum, and in this embodiment, the inner cylinder 73 on the hub shaft 52 side has an elongated hole 63.
When the ratchet gear 77 and the hollow cylindrical case 60 are concentric with each other, the eccentricity of the ratchet gear 77 and the hollow cylindrical case 60 is automatically maintained in a state of o, and the rotation ratio of the sprocket 62 and the wheel 78 is 1: 1.
Becomes Next, when the force applied to the pedal is reduced, the chain
Since the tension of 76 is gradually weakened and the arm 56 moves upward with the pivoting portion 57 as a fulcrum by the restoring force of the spring 64, the hollow cylindrical case 60 gradually becomes eccentric with respect to the ratchet gear 77 and shifts ( When the inner cylinder 73 on the hub shaft 52 side engages with the lower end of the elongated hole 63, the hollow cylindrical case 60 enters the maximum eccentric state, and the gear is automatically changed at the maximum speed ratio (speed increasing ratio). It

In this embodiment, since the ratchet pawls 65, 65A have continuous tooth portions 66, 66A whose phases are out of phase with each other as in the above-mentioned embodiment, the drive range D shifts to the (-) side and pulsation is prevented accordingly. This has the same effect as the above-mentioned embodiment.

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, for example, to the crankshaft side or the rear wheel side, automatic shift or manual shift. Further, although one set of ratchet pawls has been described as two, it may be three or more, and in that case, the gap t in FIG. 9 can be further reduced, and therefore the drive range further shifts to the (-) side, resulting in good pulsation. Can be prevented.

[Advantages of the Invention] The present invention provides an input side rotating member, a plurality of ratchet pawls disposed in the circumferential direction of the input side rotating member, each base side being rotatably provided by one pivotal support, and the ratchet pawl. A continuously variable transmission for a bicycle, comprising: an output side rotating member having a ratchet gear for transmitting rotation by meshing with the input side rotating member and the ratchet gear for relative eccentric movement. In the device, each ratchet pawl is rotatably arranged side by side on the one pivotal support portion in a plurality of sets, and each ratchet pawl is provided with a continuous tooth portion so that the ratchet pawls forming the set are continuous. By arranging the tooth portions with the phases shifted from each other, it is possible to provide the bicycle continuously variable transmission in which the meshing transmission is improved, the pulsation is prevented satisfactorily, and the structure is simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 11 show a first embodiment of the present invention. FIG. 1 is an overall longitudinal sectional view, FIG. 2 is a perspective view, FIG. 3 is an exploded perspective view, FIG. 4 is a partially cutaway perspective view, FIG. 5 is a perspective view of a ratchet pawl, FIGS. 6 (A) and (B) and FIGS. 7 (A) and (B).
Is a cross-sectional view showing a change in the amount of eccentricity, FIGS. 8 and 9 are front views showing a meshing state of a ratchet pawl and a ratchet gear,
FIG. 10 is a perspective view showing an eccentricity amount adjusting mechanism, FIG. 11 is a use state diagram, FIGS. 12 and 13 show a second embodiment of the present invention, FIG. 12 is a longitudinal sectional view, and FIG. Shows a state of use, FIGS. 14 to 18 show a conventional example, and FIGS. 14 and 15 show a front view showing a meshing state of a ratchet pawl and a ratchet gear, and FIG.
FIG. 17 is a graph showing the relationship between the ratchet pawl support shaft position and the gear ratio, and FIGS. 17 and 18 are graphs showing the relationship between the crank rotation angle and the gear ratio. 12,60 …… Input side rotating member 13,13A, 65,65A …… Ratchet claw 16,16A, 66,66A …… Teeth 15,67 …… Pivot support (Axis) 29,77 …… Ratchet gear (Output Side rotating member)

Claims (1)

[Claims] 1. An input side rotating member, a plurality of ratchet pawls arranged in the circumferential direction of the input side rotating member, each base side being rotatably provided by one pivotal support, and the ratchet pawls meshing with the ratchet pawl. In the continuously variable transmission for a bicycle, which comprises an output side rotating member having a ratchet gear to which rotation is transmitted, and which shifts the input side rotating member and the ratchet gear by relatively eccentric movement. A plurality of the ratchet pawls are rotatably arranged side by side on the one pivotal support portion as a set, and each ratchet pawl is provided with a continuous tooth portion, and the ratchet pawls forming the set have continuous tooth portions. A continuously variable transmission for a bicycle, which is characterized by arranging the two with their phases shifted.