JPH06255561A - Automatic gear for bicycle - Google Patents

Abstract

PURPOSE: To realize automatic transmission similar to feeling of a body by moving a dynamometer on an output shaft in accordance with a torque at a transmission shaft so as to select one of plural transmission gears by a transmission unit in accordance with the moving position of the dynamometer to directly measure the stepping force of a pedal. CONSTITUTION: Plural driving wheels 6a to 6d of different diameters are fixed to a driving shaft 3 integrally rotating with a pedal shaft 4. Plural transmission gears respectively engaged with the wheels 6a to 6d are fitted to a transmission shaft 10 disposed at a position separated from a driving shaft 3 via a clutch panel 15. In addition, the torque of the shaft 100 is transmitted to an output shaft 20 disposed coaxially with this via a spiral spring and a dynamometer 22 is moved stepwise on the shaft 20 in accordance with this torque. Then, one of the gears 12a to 12d is selected by a transmission unit 46 in accordance with this the moving position of the dynamometer 22. Thus, the stepping force of a pedal is directly measured to attain automatic transmission similar to feeling of a body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bicycle automatic transmission and, more particularly, to an automatic transmission capable of automatically changing a gear ratio between a drive shaft and a transmission shaft in accordance with a rotational force of the transmission shaft. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, as a bicycle automatic transmission, for example, one disclosed in Japanese Patent Laid-Open No. 63-137090 is known. This automatic transmission comprises a plurality of ratchet pawls provided on the inner periphery of an input side rotating member integrally formed with a sprocket, and a ratchet gear fixed to the hub of a wheel and located on the center side of the input side rotating member. Is equipped with the
The speed is automatically changed steplessly according to the amount of eccentricity.

[0003]

However, in the above-mentioned conventional automatic transmission, the structure is such that the gear is changed based on the tension of the chain applied to the sprocket.
There is a problem that the pedaling force from the pedal does not appear as the change of the eccentricity when the slack of the chain is taken into consideration.

[0004]

In view of the above, an automatic gear shift device for a bicycle according to the present invention is designed to directly measure the pedaling force of a pedal so that the automatic gear shift can be performed in a more realistic manner.

That is, the automatic transmission for a bicycle according to the present invention includes a drive shaft that is rotatably mounted on a bicycle chassis and rotates integrally with a pedal shaft, and a plurality of drive wheels that are fixed to the drive shaft and have different diameters. And a transmission shaft arranged at a position distant from the drive shaft and rotatably attached to the chassis of the bicycle, and attached to the transmission shaft via a clutch plate and meshes with the plurality of drive wheels. A plurality of transmission gears, an output shaft coaxially arranged with the transmission shaft, one end of which is supported by a bicycle chassis and the other end of which is supported by one end of the transmission shaft, and which transmits a rotational force to a chain sprocket, A dynamometer that transmits the rotational force of the transmission shaft to the output shaft via an elastic member and moves stepwise on the output shaft according to the magnitude of the rotational force of the transmission shaft, and this dynamometer is a switching lever. And a transmission unit that selects one of the transmission gears according to the moving position of the dynamometer, and connects a clutch plate to the transmission gear selected by the transmission unit to rotate the transmission gear on a transmission shaft. And a switching drive mechanism for transmission.

[0006]

According to the above-mentioned means, the pedaling force when pedaling is transmitted from the drive shaft to the transmission shaft via the drive wheel and the transmission gear. At this time, the rotational force from the transmission gear to which the clutch plate is connected is transmitted to the transmission shaft.
The rotational force of the transmission shaft is transmitted to the output shaft via the dynamometer, causing the chain sprocket to rotate. On the other hand, the dynamometer moves on the output shaft according to the magnitude of the rotational force of the transmission shaft, and drives the transmission unit according to the amount of movement. Then, the transmission gear connected to the clutch plate is switched by the mode switching from the transmission unit, and the gear ratio is automatically changed. In this way, the dynamometer constantly measures the rotational force of the transmission shaft, and switches the gear ratio between the drive shaft and the transmission shaft wheel to an appropriate one that matches the user's experience.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of an automatic transmission for a bicycle according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a schematic explanatory view showing an arrangement location of the automatic transmission D, and FIG. 2 is a schematic plan view of the automatic transmission D. In this figure, reference numerals 2a and 2b are left and right side walls of a chassis 1 which constitutes the automatic transmission D, 3 is a drive shaft rotatably attached to the left and right side walls 2a and 2b, and 4 is both ends of the drive shaft 3. It is a pedal shaft connected to the section, and transmits the pedaling force to the drive shaft 3 when the pedal 5 is pedaled. On one side of the drive shaft 3, four drive wheels 6a, 6b, 6c, 6d having different diameters are sequentially arranged from the larger one. These drive wheels 6a, 6b, 6
The centers of c and 6d are fixed to the drive shaft 3,
As the drive shaft 3 rotates, it rotates with it. Each of the drive wheels 6a, 6b, 6c, 6d has a structure in which a large number of rollers 7 are arranged on the outer periphery thereof.

On the other hand, a transmission shaft 10 is arranged in parallel with the drive shaft 3 at a front position away from the drive shaft 3. The transmission shaft 10 has one end rotatably attached to the left side wall 2a of the chassis 1 and the other end rotatably attached to a vertical wall 11 provided upright in the center of the chassis 1. Further, transmission gears 12a, 12b, 12c, 12d are also arranged on the transmission shaft 10 at positions corresponding to the drive wheels 3.
The transmission gears 12a, 12b, 12c, 12d are attached to the transmission shaft 10 via bearings 13, respectively. In addition, these transmission gears 12a, 12b,
12c and 12d are arranged in order from the smallest diameter, and by engaging with the rollers 7 of the drive wheels 6a, 6b, 6c and 6d, the drive wheels 6a, 6b, 6c and 6d are rotated. All transmission gears 12a, 12b, 12c,
12d will rotate. Further, a plurality of grooves 14 are cut on the circumferential surface of the transmission shaft 10 in the axial direction, and the clutch plate 15 slidingly moving in the grooves 14 is a bearing 13 of each of the transmission gears 12a, 12b, 12c, 12d. It is provided adjacent to the neighborhood. Therefore, the clutch plate 15 slides to move the transmission gears 12a, 12b, 1
2c, 12d, the transmission gears 12a, 12b,
The rotational force of 12c and 12d is transmitted to the transmission shaft 10 through the clutch plate 15.

In this embodiment, an output shaft 20 is arranged coaxially with the transmission shaft 10. The output shaft 20 has one end rotatably supported by the right side wall 2b of the chassis 1 and the other end connected to the end of the transmission shaft 10 by a bearing 21. And, a dynamometer 22 is arranged in the vicinity of a connecting portion between the transmission shaft 10 and the output shaft 20,
Transmission of power from the transmission shaft 10 to the output shaft 20 and transmission gears 12a, 12b, 12c, 1 connected to the transmission shaft 10.
The selection of 2d is made by this dynamometer 22.

As shown in FIGS. 3 and 4, the dynamometer 22 has a space between an inner cylindrical body 23 fixed to the tip of the transmission shaft 10 and a collar 24 extending from the end of the output shaft 20. A spiral spring 25 as an elastic member is provided in the, and the magnitude of the rotational force is measured by twisting the spiral spring 25. The spiral spring 25, as shown in FIG.
One end is fixed to the inner wall of the inner tubular body 23 and the other end is fixed to the outer wall of the collar 24, and the outer wall of the outer wall is wound so as to be arranged in the space between the inner wall and the outer wall. Further, a stepped locking step portion 26 extending along the circumference is formed on the other end side of the inner cylindrical body 23. A pair of the locking step portions 26 are provided at opposite positions on the circumference, the number of steps corresponds to the number of the drive wheels 6 and the transmission gears 12, and the engaging recessed portions 27 are formed for each step. is doing. It should be noted that the adjacent engaging recesses 27 are separated by smooth wave-shaped peaks.

On the other hand, an outer cylinder 28 is arranged on the output shaft 20 so as to surround the inner cylinder 23. Output shaft 20
An axial groove 29 is formed on the circumferential surface of the outer cylindrical body 28. One end 28a of the outer cylindrical body 28 is slidably attached to the groove 29, and the other end side of the outer cylindrical body 28 has the above-mentioned engagement. A pair of locking claws 30 are provided facing inward so as to ride over each wave peak of the stop 26 and engage with the engaging recess 27. A coil spring 31 is mounted on the outer periphery of the output shaft 20 between the collar 24 and one end portion 28a of the outer tubular body 28 to constantly urge the outer tubular body 28 toward the right side wall 2b.
Further, an output gear 31 is attached to the end of the output shaft 20, and an output ring 34 attached to the end of the drive shaft 3 via a bearing 33 is engaged with the output gear 31 to output the output wheel 3.
5 is fixed, and the drive shaft 3 transmitted to the output shaft 20.
Is transmitted to the sprocket 36 via the output gear 32 and the output wheel 35 to rotate the chain 8 wound around the sprocket 36.

Therefore, in the dynamometer 22 having the above-described structure, when the rotational force is transmitted from the drive shaft 3 to the transmission shaft 10 via the drive wheel and the transmission gear, the rotational force is transferred to the inner cylinder. It is transmitted to the spiral spring 25 through the body 23. At this time, since the rotational force of the transmission shaft 10 that rotates the output shaft 20 varies depending on the pedaling force of the pedal 5 and the resistance force that enters the output shaft 20 through the sprocket 36, the swirl depends on the magnitude of this rotational force. The torsional strength of the spring 25 is different, and the sliding position of the outer cylinder 28 is also different depending on the torsional strength. That is, when the transmission shaft 10 is rotated, the spiral spring 25 is not twisted and the output shaft 2
When 0 rotates, the outer cylinder body 28 holds the position shown in FIG. 4, but when the spiral spring 25 is twisted due to the resistance force of the output shaft 20 or the like, the outer shaft body 28 is attached to the output shaft 20 relative to the transmission shaft 10. Since the rotation is delayed, the locking claw 30 of the outer cylinder 28 rides over one wave peak of the locking step 26. As a result, the outer cylinder 28 is pulled along the output shaft 20 against the coil spring 31 and slides, and the locking claw 30 engages with the next engagement recess 27 of the locking step 26. become. As the resistance force of the output shaft 20 increases and the rotational force of the transmission shaft 10 increases, the torsion of the spiral spring 25 increases, so that the sliding distance of the outer cylindrical body 28 increases and the locking claw 30 engages. It engages with the engaging recess 27 at a higher position of the stop 26. In this way, the above-described operation is repeated until the rotational force of the transmission shaft 10 and the resistance force of the output shaft 20 are in equilibrium, and finally the rotational force on the transmission shaft 10 side is changed to the output shaft 20 side. When the rotations of the two are completely transmitted to each other and their rotations are synchronized, the position of the outer cylindrical body 28 is held and the transmission shaft 10 and the output shaft 20 start rotating together.

On the other hand, when the output shaft 20 starts to rotate and the rotational force of the transmission shaft 10 becomes smaller than that when the output shaft 20 is started, the spiral spring 25 instantaneously returns in the returning direction, so that the transmission shaft 10 moves. There is a delay in rotation. As a result, the elastic force of the coil spring 31 causes the outer cylindrical body 28 to slide along the output shaft 20 in the direction in which the outer cylindrical body 28 is pushed back. This time, contrary to the above, the locking claw 30 of the outer cylindrical body 28 causes the locking step portion 26 to move. One wave peak is returned to engage with the engaging recess 27 on the front side. The same operation is repeated until the transmission shaft 10 and the output shaft 20 are balanced, and the transmission shaft 10 and the output shaft 20 rotate together at the position where the forces of both shafts are balanced.

The dynamometer 22 has a spiral spring 25.
A delay ratchet 40 is disposed adjacent to the. This delay ratchet 40, as shown in FIG.
It is composed of a stopper portion 41 provided at equal intervals on the outer peripheral surface of the collar 24 of 0, and an arm member 42 attached to the inner peripheral surface of the inner cylindrical body 23 of the transmission shaft 10. The arm member 42 has a first arm 42a that is axially supported by the inner peripheral surface and has a tip portion curved toward the inner peripheral surface of the inner cylindrical body 23, and a tip portion that is pivotally supported by an intermediate portion of the first arm 42a. The second arm 42b is slightly curved toward the outer peripheral surface of the collar 24.
The second arm 42b is composed of a leaf spring, and the tip end portion of the second arm 42b is elastically bent and deformed by being pressed against the stopper portion 41, and the tip end portion of the first arm 42a is moved to the inner peripheral surface of the inner cylindrical body 23. Press against. Therefore, the arm member 42 includes the first arm 42a and the second arm 42b.
By thrusting and on the inner cylindrical body 23 and the collar 24, the integral rotation of the transmission shaft 10 and the output shaft 20 is ensured.

A circumferential groove 37 is cut on the outer circumference of one end of the above-mentioned outer cylinder, and one end of a switching lever 38 is rotatably connected to the circumferential groove 37. This switching lever 38
Are designed to move together with the sliding movement of the outer cylinder 28. On the other hand, the transmission unit 46 is connected to the other end of the switching lever 38. This transmission unit 46
Is, as shown in FIGS. 7 and 8, the switching lever 38.
The other end of which is connected and which rotates according to the amount of movement of the switching lever 38, a gear group 48 provided at the upper end of this rotation shaft 47, and a left and right switching operation by rotation of this gear group 48. A pair of ratchets 49a, 49b,
It is composed of four switching rods 50a, 50b, 50c, 50d arranged between the left and right ratchets 49a, 49b. The gear group 48 includes a main gear 48a that rotates integrally with the rotating shaft 47, and main gears 48a that are located on the left and right sides of the main gear 48a.
It is composed of a pair of auxiliary gears 48b and 48c that rotate in association with a. The auxiliary gears 48b and 48c and the ratchet 4
9a and 49c are coaxial, and auxiliary gears 48b and 48
As c rotates, ratchets 49a and 49b also move in the same manner. As shown in FIG. 8, each of the left and right ratchets 49a and 49b has four sheets in the vertical direction, and each ratchet 49a, 49b is arranged with a predetermined angle difference.
Further, each ratchet 49a, 49b has a substantially arcuate shape, but the arcuate directions are left and right opposite.

The switching rods 50a, 50b, 50c, 50
d is arranged in a state where four ratchets 49a and 49b are overlapped with each other in the vertical direction, and triangular locking projections 5 are provided near the ratchets 49a and 49b.
1a, 51b, 51c and 51d are provided respectively. The locking projections 51a, 51b, 51c and 51d have switching rods 50a, 50b, 50c and 50 each having a triangular top.
While being swingably supported by d, the other tops thereof project on both sides of the switching rods 50a, 50b, 50c, 50d. Therefore, as shown in FIGS. 7 and 9, by pushing out the left and right protruding portions of the locking projections at the tips of the ratchets 49a and 49b, it is possible to push out only one selected switching rod forward. it can. In addition, each switching rod 50
A coil spring 52 is bridged between a, 50b, 50c, 50d and the chassis 1, and the ratchets 49a, 49b and the locking projections 51a, 51b, 51c, 5 are provided.
When the engagement with 1d is released, the switching rods 50a, 50b, 50c, 50d are pulled back by the action of the coil spring 52, and at the same time, the locking projections 51a, 51b, 51c, 51d are elastically returned to their home positions. In addition, ratchet 4
The switching rod 50 has 9a and 49b on the left and right respectively.
This is because it corresponds to both the case of switching a, 50b, 50c, and 50d from top to bottom and the case of switching from bottom to top.

The switching rods 50a, 50b, 50c, 50
As shown in FIGS. 1 and 2, the tip portion of d has the drive wheels 6a, 6b, 6c, 6d and the transmission gears 12a, 12b,
It extends to the vicinity of the meshing portion with 12c and 12d. Further, the lengths of the tip portions are different from each other, gradually increasing from the top to the bottom, and the operation rods 54a, 54b, 54c, 54d are pivotally supported on the tip portions.
The operating rods 54a, 54b, 54c, 54d are connected to the above-mentioned clutch plate 15 via connecting rods 55a, 55b, 55c, 55d which are erected vertically, and the switching rods 50a, 50b, 50c, 50d. When is extended, the coupling plate 55a, 55b, 55c, 55d is rotated to slide the clutch plate 15 along the transmission shaft 10, and the clutch plate 15 is connected to a predetermined transmission gear 12 to connect the transmission shaft 10 to the transmission shaft 10. The driving force can be transmitted. Reference numeral 56 is an auxiliary spring for disengaging the clutch plate 15, and 57 is a reinforcement.

Next, the operation of the automatic transmission D having the above structure will be described. The automatic transmission D is held in the state shown in FIG. 1 when the bicycle is stopped.
When the user tries to start the bicycle by pedaling on the pedal 5, the pedaling force is transmitted to the drive shaft 3 through the pedal shaft 4 to rotate the four drive wheels 6a, 6b, 6c, 6d. The transmission gears 12a, 12b, 12c, 12d rotate because they are engaged with the drive wheels 6a, 6b, 6c, 6d, but as shown in FIG. 2, they are initially connected to the clutch plate 15. The rotational force of the transmission gear 12a is transmitted to the transmission shaft 10. Then, as the transmission shaft 10 rotates, the remaining three transmission gears 12b, 12c, 12d run idle. The rotational force of the transmission shaft 10 is the vortex spring 2 of the dynamometer 22.
5 is measured, but output shaft 2 as at the start
When the resistance force on the 0 side is large, the rotational force of the transmission shaft 10 is not transmitted to the output shaft 20 as it is, the torsion of the spiral spring 25 becomes strong, and the inner cylindrical body 26 rotates together with the transmission shaft 10. As a result, the outer cylindrical body 28 slides along the output shaft 20 against the coil spring 31, and the locking claw 30 goes over one wave crest of the locking step portion 26 and engages with the next engaging recess 27. To do. Therefore, the switching lever 38 also slides together with the outer cylindrical body 28 to rotate the rotating shaft 47 accordingly. The gear groups 48 are driven in accordance with the movement of the rotary shaft 47, and as shown in FIG. 7, the ratchets 49a and 49b.
Rotate in the direction of the arrow. As a result, the ratchets 49a and 49b are disengaged from the locking projections 51a of the switching rod 50a, so that the switching rod 50a moves to the coil spring 5a.
While being returned by the return force of 2, the operating rod 54a returns to the spring and rotates to disconnect the clutch plate 15 from the transmission gear 12a. On the other hand, this time, the ratchets 49a and 49b are engaged with the locking projections 51b of the switching rod 50b to push out the switching rod 50b. Therefore, the adjacent operating rod 54b rotates to connect the clutch plate 15 to the transmission gear 12b, so that the driving force from the drive wheel 6b is transmitted to the transmission shaft 10 via the transmission gear 12b this time. Become. In this case, the gear ratio between the drive wheel and the transmission gear is different from that at the time of star, and the diameter of the drive wheel 6b is smaller, while the diameter of the transmission gear 12b is oppositely larger. Even if the user pedals with pedaling force, a large rotational force can be applied to the transmission shaft 10. Especially at the start, pedal 5 with great pedaling force
Since a large rotational force is applied to the transmission shaft 10 by rowing, the locking claw 30 of the outer cylindrical body 28 instantaneously overcomes a plurality of wave crests of the locking step portion 26 and is at the highest engaging concave portion. Engage with 27. As a result, mode selection in the transmission unit 46 and switching of the transmission gears from 12a to 12d through 12b and 12c are instantaneously performed, and the bicycle is rowed with the foot load on the pedal 5 being most reduced. be able to.

Once the bicycle has started, the output shaft 20
Since the resistance force on the side is reduced, the rotational force of the transmission shaft 10 can be smaller than that at the start. Therefore, spiral spring 2
The twist of 5 is released a little from the state at the start, and the rotation of the transmission shaft 10 is delayed. Therefore, the outer cylindrical body 2
8 is slid along the output shaft 20 in the opposite direction to the above by the elastic force of the coil spring 31, and the engagement between the locking claw 30 and the engagement recess 27 is deviated by one. Then, the ratchets 49a and 49b are rotated in the opposite direction to the direction described above via the switching lever 38 to extend the switching rod one step lower to switch the transmission gears. As a result, when the bicycle starts running, the transmission gear is automatically switched to 12b or 12c, and the pedal 5 can be pedaled in a state of a gear combination that is lighter than that at the start.

When running on a flat road is changed to running on a slope, a load is applied to the pedal 5, so that the rotational force of the transmission shaft 10 increases. As a result, since the transmission gear is automatically switched to 12d and the combination of the lightest gears is achieved, even if the pedal 5 is pedaled with the same pedaling force as before, a large rotational force can be transmitted to the transmission shaft 10. , You can climb the slope easily.

Further, when the left and right pedals 5 are alternately rowed, when the driving force is transferred from one pedal to the other pedal, a state occurs in which the driving force is not momentarily applied.
At that time, in order to prevent the above-described delay ratchet 40 from operating and instantaneously releasing the spiral spring 25 of the dynamometer 22, the combination of the transmission gears connected to the transmission shaft 12 up to that time is prevented. Can be held.

Since the above-described automatic transmission device D has a structure additionally provided at the base of the pedal shaft 4 unlike the case where the automatic transmission device D is provided at the rear wheel of the bicycle, it is attached to an existing bicycle by a simple modification. be able to. In addition, by appropriately selecting the strength of the spiral spring 25, it is possible to perform automatic gear shifting suitable for the rider.

[0023]

As described above, according to the automatic transmission for a bicycle according to the present invention, the dynamometer is arranged between the transmission shaft and the output shaft, and the rotational force of the transmission shaft when pedaling is pedaled. Since the gear of the transmission shaft is automatically switched according to the size of the, there is an effect that traveling suitable for the experience can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an outline of an automatic transmission for a bicycle according to the present invention.

FIG. 2 is a plan view of the automatic transmission.

FIG. 3 is a perspective view of a dynamometer.

FIG. 4 is a sectional view taken along the line AA in FIG.

5 is a sectional view taken along line BB in FIG.

6 is a cross-sectional view taken along the line CC of FIG.

FIG. 7 is a plan view of a transmission unit.

8 is a cross-sectional view taken along line DD in FIG. 7.

FIG. 9 is an explanatory diagram showing the operation of the transmission unit.

[Explanation of symbols]

 1 chassis 3 drive shaft 4 pedal shaft 6a, 6b, 6c, 6d drive wheel 10 transmission shaft 12a, 12b, 12c, 12d transmission gear 15 clutch plate 20 output shaft 22 dynamometer 25 spiral spring (elastic member) 38 switching lever 46 speed change unit

Claims (1)

[Claims] 1. A drive shaft that is rotatably attached to a chassis of a bicycle and rotates integrally with a pedal shaft, a plurality of drive wheels having different diameters fixed to the drive shaft, and a drive shaft that is separated from the drive shaft. A transmission shaft disposed and rotatably attached to the bicycle chassis; a plurality of transmission gears that are attached to the transmission shaft via a clutch plate and that respectively engage with the plurality of drive wheels; and coaxial with the transmission shaft. An output shaft that is disposed above and has one end supported by a bicycle chassis and the other end supported by one end of a transmission shaft, and an output shaft that transmits a rotation force to a chain sprocket, and the rotation force of the transmission shaft through an elastic member. A dynamometer that transmits to the output shaft and moves stepwise on the output shaft according to the magnitude of the rotational force of the transmission shaft, and this dynamometer is connected by a switching lever and the moving position of the dynamometer A transmission unit for selecting one of the transmission gears according to the above, and a switching drive mechanism for connecting a clutch plate to the transmission gear selected by the transmission unit and transmitting the rotation of the transmission gear to the transmission shaft. An automatic transmission for a bicycle, comprising: