JP2010076512A - Driving structure for cycles - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving structure for cycles that lightens burden on feet of a rider and is superior in durability. <P>SOLUTION: A driving structure 10 for cycles has a function for crank arms 15 and 16 to periodically expand and contract in radius directions of rotating pedals 17 and 18, respectively, when the pedals 17 and 18 are pumped and rotated. The crank arms 15 and 16 have cylindrical fixed arms 15b and 16b, respectively, mounted to a crank shaft 12, cylindrical movable arms 15a and 16a slidably inserted in the fixed arms 15b and 16b, respectively, in their axial directions, pedals 17 and 18 pivoted on ends of the movable arms 15a and 16a, respectively, rotating rods rotatably held axially in the movable arms 15a and 16a, screw mechanisms for screwing the rotating rods and each of the fixed arms 15b and 16b together, and reversing mechanisms for normally or reversely rotating the rotating rods every time the crank shaft 12 rotates 180° because the pedals 17 and 18 are pumped. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a driving structure used for a portion that transmits a driving force generated by a pedal depression of a bicycle to a crankshaft.

  Conventionally, the distance between the crankshaft and the pedal spindle (crank arm length) periodically expands and contracts as the pedal is stepped on while riding to reduce the burden on the rider's leg when riding a bicycle. A mechanism has been proposed (see, for example, Patent Documents 1 and 2). The drive mechanism described in Patent Documents 1 and 2 has a function in which the crank arm extends in a region where the maximum stepping force can be exerted within the pedal rotation range during traveling of the bicycle, and the crank arm contracts in other regions. It has.

JP 2005-271894 A JP 7-89477 A

  The “bending and stretching crank mechanism” described in Patent Document 1 is provided with a complicated rotation transmission mechanism including a pair of sprockets and a chain in a portion corresponding to a crank arm of a conventional bicycle. Therefore, the effect of reducing the physical burden on the passenger who rides the pedal is low. In addition, when used for a long period of time, the chain in the rotation transmission mechanism may extend and come off from the sprocket, which requires maintenance.

  The “bicycle drive device” described in Patent Document 2 is simpler than the “bend-extend crank mechanism” described in Patent Document 1, but as the crank arm rotates, the driven pin and the roller of the expansion / contraction section guide the expansion / contraction guide. Since the structure moves in the groove, the pedal depression force of the passenger may be consumed by friction. Further, noise generated from a roller or the like moving in the guide groove of the telescopic guide cannot be ignored. Furthermore, if the telescopic guide is deformed or the driven pin or the roller is worn during long-term use, a great burden is imposed on the rotation of the pedal.

  The problem to be solved by the present invention is to provide a bicycle drive structure that can reduce a burden of leg force of a passenger and is excellent in durability.

The bicycle drive structure of the present invention is a bicycle drive structure in which the crank arm periodically expands and contracts in the rotational radial direction as the pedal is depressed and rotated during traveling.
The crank arm is pivotally supported on the distal end side of the movable arm, a cylindrical fixed arm attached to the crankshaft, a cylindrical movable arm inserted in the fixed arm so as to be slidable in the axial direction. The pedal, a rotating rod that is rotatably held on a substantially axial center of the movable arm, a screw mechanism that screws the rotating rod and the fixed arm within the fixed arm, and a stepping operation of the pedal. Along with this, there is provided a reversing mechanism for rotating the rotating rod forward and reverse each time the crankshaft rotates 180 degrees.

  With such a configuration, each time the crankshaft rotates 180 degrees as the pedal is depressed, the reversing mechanism causes the rotating rod in the movable arm to rotate forward and backward, thereby fixing it via the screw mechanism. Since the rotating rod screwed with the arm advances and retreats in the axial direction within the fixed arm, the entire crank arm periodically expands and contracts in the direction of the rotating radius. Therefore, the crank arm extends in a range where the pedal rotates from the rearmost position to the foremost position with reference to the traveling direction of the bicycle, and the crank arm contracts in a range where the pedal rotates from the frontmost position to the rearmost position. If the reversing mechanism is set in this way, the burden of leg strength can be reduced. Note that the relationship between the rotation range of the pedal and the expansion and contraction of the crank arm is not limited to the above, and can be set according to individual differences in the region where the leg force is applied.

  In addition, it is provided with a rotation rod that is rotatably held in the movable arm and screwed to the fixed arm, and a reverse rotation mechanism that rotates the rotation rod forward and backward according to the rotation of the crankshaft. Since it does not require a chain that easily stretches over time, or a rail or roller that easily wears, it has excellent durability.

  Here, the reversing mechanism is provided on the rotating rod in a state where it can mesh with the first stage gear at a symmetrical position across the rotation center of the first stage gear and the first stage gear rotating in conjunction with the rotation of the pedal. Two final gears, and a region of less than 180 degrees along the rotation direction on the gear surface of the first gear is a toothed region that can be meshed, and the remaining region is a toothless region that is not meshable. Is desirable.

  With this configuration, every time the pedal rotates 180 degrees with respect to the movable arm, the first gear also rotates 180 degrees, and the meshing area of the gear surface of the first gear alternates between the two final gears provided on the rotating rod. Rotating rod rotates forward and backward by meshing with. In other words, the meshing area of the first stage gear is alternately meshed with the two last stage gears so that the rotating rod is rotated forward and reverse, so that the reversing operation can be reliably performed according to the rotation of the pedal, and the durability is improved. Is also excellent.

  On the other hand, as the reversing mechanism, a first-stage gear that rotates in conjunction with the rotation of the pedal, two middle-stage gears that can mesh with the first-stage gear at 180 ° opposed positions across the rotation center of the first-stage gear, Two final gears provided on the rotating rod in a state of meshing with the middle gear, respectively, and a region of less than 180 degrees along the rotation direction on the gear surface of the first gear is set as a toothed region that can be meshed. The remaining region can be a toothless region that cannot be meshed.

  With such a configuration, by rotating the intermediate rod between the first gear and the final gear, and changing the gear ratio of these gears, the rotation amount of the rotating rod while the pedal rotates 180 degrees Therefore, the degree of freedom in design when setting the amount of expansion and contraction of the crank arm that expands and contracts by the rotation of the rotating rod is increased.

  Next, if a pedal holding means is provided to keep the posture of the pedal substantially constant, a predetermined rule between the rotational movement of the crank arm and the expansion and contraction movement due to the idling of the pedal while stopping or parking the bicycle, etc. It is possible to prevent the characteristics from breaking.

  Here, as the pedal holding means, a flexible tension transmitting member having both ends locked to the rotating parts of the left and right pedals, and a bicycle for holding the central portion of the tension transmitting member movably And a pulley rotatably supported on a part of the pulley. With such a configuration, the left and right pedals are restrained from each other by the tension transmission member, so that it is possible to prevent the pedals from idling while stopped or parked. Further, since the tension transmitting member reciprocates in the longitudinal direction via the pulley in accordance with the crank movement of the left and right pedals, there is no problem in the operation of depressing the traveling pedal.

  On the other hand, as the pedal holding means, a weight can be provided at a position lower than the rotation center of the pedal. With such a configuration, since the pedal is held in a constant posture by the vertically downward gravity acting on the weight, it is possible to prevent the pedal from idling other than during traveling.

  According to the present invention, it is possible to provide a bicycle drive structure that can reduce the burden on the leg strength of the passenger and is excellent in durability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a plan view showing a bicycle drive structure according to the first embodiment of the present invention, FIG. 2 is a right side view of the bicycle drive structure shown in FIG. 1, and FIG. 3 is a right side of the bicycle drive structure shown in FIG. FIG. 4 is a schematic view showing the rotation locus of the right pedal shown in FIG. 3.

  As shown in FIGS. 1 and 2, the bicycle drive structure 10 of the present embodiment is accompanied by the stepping rotation of the left and right pedals 17 and 18 when the bicycle (not shown) is traveling in the direction of arrow R. When the crankshaft 12 rotates in the direction of the arrow 12R, the left and right crank arms 15 and 16 have a function of periodically expanding and contracting in the rotational radius direction. That is, when the movable arms 15a and 16a constituting the crank arms 15 and 16 come out and enter along the axial direction from the fixed arms 15b and 16b, respectively, the entire crank arms 15 and 16 expand and contract.

  As shown in FIG. 3, when the right pedal 17 and the crank arm 15 are rotated in the direction of the arrow by the stepping action of the passenger (not shown), the traveling direction of the bicycle (the direction of the arrow R) is used as a reference. When the pedal 17 is in the foremost position (3 o'clock position), the crank arm 15 extends to the longest, and when the pedal is in the final position (9 o'clock position), the crank arm 15 contracts to the shortest. That is, the crank arm 15 is continuously extended while the pedal 17 rotates from the rearmost position (9 o'clock position) to the foremost position (3 o'clock position), and the pedal 17 is moved to the foremost position (3 o'clock position). ) To the rearmost position (9 o'clock position), the crank arm 15 continuously contracts. Therefore, as shown in FIG. 4, the rotation locus Q of the pedal 17 draws a substantially heart shape in the horizontal direction. The same applies to the left pedal 18 and the crank arm 16.

  Next, the structure near the right pedal and crank arm will be described with reference to FIGS. 5 is an exploded sectional view showing a part of the bicycle drive structure shown in FIG. 1, FIG. 6 is a sectional view showing a state where the right crank arm is extended in the bicycle drive structure shown in FIG. 1, and FIG. 8 is a cross-sectional view taken along the line AA in FIG. 5, FIG. 9 is a cross-sectional view taken along the line BB in FIG. 5, and FIG. 10 is a cross-sectional view taken along the line CC in FIG. FIG. 11 is a view of the first gear shown in FIG. 6 as viewed from the bearing side. Since the structure near the left pedal and crank arm is mirror-symmetrical with the right structure, only the right structure will be described below.

  As shown in FIG. 5, the crank arm 15 has a cylindrical fixed arm 15b fixed to the right end of the crankshaft 12, and a cylindrical shape inserted into the fixed arm 15b so as to be slidable along the axial direction. Movable arm 15a, and a pedal 17 pivotally supported via a pedal shaft 17a on the distal end side of the movable arm 15a. Like a general bicycle, the crankshaft 12 is rotatably supported by the bottom bracket 11, and a chain 14 for driving rear wheels is hung on a chain ring 13 attached to the right side of the crankshaft 12.

  The fixed arm 15b has a base end detachably fixed to the right end of the crankshaft 12 using a screw 32, and a female screw portion 21 and two groove portions 22 are formed on the inner peripheral surface thereof. Yes. As shown in FIG. 8, the two groove portions 22 are formed in parallel to the axis at positions facing each other across the axis of the fixed arm 15b. On the other hand, as shown in FIG. 10, two protrusions 27 are formed on the outer peripheral surface of the movable arm 15 a so as to be slidably inserted into the two grooves 22. These protrusions 27 are also formed in parallel with the axis at positions facing each other across the axis of the movable arm 15a.

  As shown in FIG. 5, an outer periphery of a short cylindrical rotary slider 25 integrally formed at the tip of the rotary rod 24, which is rotatably held on a substantially axial center in the movable arm 15a. A male thread portion 26 is formed on the inner surface. Further, a locking mechanism for preventing the rotating rod 24 from moving in the axial direction in the movable arm 15a is provided in a portion where the rotating rod 24 penetrates the proximal end wall portion 15x of the movable arm 15a. . As shown in FIG. 6, this locking mechanism has a flange-shaped enlarged diameter portion 24f formed on the outer periphery of the rotating rod 24, and the enlarged diameter portion 24f is rotatably held. The locking groove 15t is formed in the inner periphery of the through hole 15s along the circumferential direction.

  As shown in FIG. 6, the rotary slider 25 is inserted into the fixed arm 15b, the male screw portion 26 on the outer periphery of the rotary slider 25 is screwed to the female screw portion 21 on the inner periphery of the fixed arm 15b, and the protrusion of the movable arm 15a. When the rotary rod 24 is rotated forward and backward with the portion 27 fitted in the groove 22 of the fixed arm 15b, the movable arm 15a enters and exits the fixed arm 15b. In this case, since the protrusion 27 of the movable arm 15a is fitted in the groove 22 of the fixed arm 15b, the movable arm 15a can slide only in the axial direction with respect to the fixed arm 15b. In the present embodiment, the male screw portion 26 and the female screw portion 21 constitute a “right screw type” screw mechanism.

  As shown in FIG. 10, the ball 23 is accommodated in a recess 15d provided in the vicinity of the distal end opening of the inner periphery of the fixed arm 15b, and the ball 23 is rotated by the recess 15d and the groove 15c of the outer periphery of the movable arm 15a. It is held freely. The ball 23 exhibits a bearing function when the movable arm 15a advances from the fixed arm 15b in a state where a strong stepping force is applied to the pedal 17.

  As shown in FIGS. 6 and 7, a reversing mechanism 19 is provided at a connecting portion between the pedal shaft 17a and the movable arm 15a. The reversing mechanism 19 has a function of rotating the rotating rod 24 forward and backward every time the crankshaft 12 rotates 180 degrees as the pedal 17 is depressed. Normally, the reversing mechanism 19 is covered with a removable cover 19a.

  The reversing mechanism 19 is positioned at 180 degrees across the first stage gear 28 attached to the pedal shaft 17a so as to rotate in conjunction with the rotation of the pedal 17, and the rotation center of the first stage gear 28 (axial center of the pedal shaft 17a). Are provided with two middle gears 29 and 30 that can mesh with the first gear 28, and two final gears 24a and 24b provided on the rotating rod 24 in mesh with the middle gears 29 and 30, respectively. . As shown in FIG. 11, a toothed region 28b that can be meshed with a region of less than 180 degrees along the rotation direction is formed on the gear surface of the first stage gear 28, and the remaining region (region indicated by an arrow line 28R: , A region where the angle exceeds 180 degrees and is less than 190 degrees).

  As shown in FIG. 7, the pedal shaft 17a and the support shafts 29a, 30a of the middle gears 29, 30 are rotatably supported by a bearing 31 fixed to the movable arm 15a. The toothed region 28b of the first gear 28 is a bevel gear, and the middle gears 29 and 30 are integrally provided with bevel gear portions 29b and 30b and spur gear portions 29s and 30s around the support shafts 29a and 30a. The final stage gears 24a and 24b are spur gears. The final gears 24a and 24b are provided at positions where they mesh with the spur tooth portions 29s and 30s of the middle gears 29 and 30, respectively.

  Here, the function of the reversing mechanism 19 will be described with reference to FIGS. 3, 4, 6, 7, and 11. As shown in FIG. 3, when the pedal 17 is in the foremost position (3 o'clock position shown by the solid line in FIG. 3), the crank arm 15 extends to the maximum, and the inside is in the state of FIG. That is, the movable arm 15a advances from the fixed arm 15b, and the rotary slider 25 is located near the tip opening of the fixed arm 15b. Further, as shown in FIG. 11, the first stage gear 28 interlocked with the pedal shaft 17a is in a state in which the toothed region 28b faces upward and the toothless region 28a faces downward. At this time, the entire length of the crank arm 15 corresponds to the length indicated by the arrow S2 in FIG.

  In the state of FIG. 6, when the pedal 17 is depressed, the crank arm 15 and the crankshaft 12 rotate in the direction of the arrow 12 </ b> R, while the pedal 17 always maintains the same posture, so the pedal 17 is relative to the crank arm 15. Will rotate in the direction of the arrow line 17R. Accordingly, the toothed region 28b of the first gear 28 meshes with the bevel tooth portion 30b of the middle gear 30 to rotate the middle gear 30, and this rotation is transmitted to the last gear 24b meshed with the spur tooth portion 30S. At the same time, the rotary slider 25 rotates in the direction of the arrow 24S. In the above process, the toothless region 28a of the first gear 28 faces the bevel tooth portion 29b of the middle gear 29 and is in a non-meshing state, so that the middle gear that is reversely driven by the last gear 24a of the rotating rod 24. The rotation of 29 is not hindered.

  Thus, when the pedal 17 rotates from the state shown in FIG. 6 toward the state shown in FIG. 7, the rotary slider 25 rotates in the direction of the arrow 24S together with the rotary rod 24, and the crankshaft moves along the inner peripheral surface of the fixed arm 15b. Therefore, the movable arm 15a is drawn into the fixed arm 15b along the axis. As shown in FIG. 3, when the pedal 17 rotates to the rearmost position (9 o'clock position indicated by a two-dot chain line in FIG. 3), the entire crank arm 15 is contracted to the shortest. The entire length of the crank arm 15 at this time corresponds to the length of the arrow line S1 in FIG.

  Thereafter, when the pedal 17 rotates from the state of FIG. 7 toward the state of FIG. 6, the crank arm 15 and the crankshaft 12 rotate in the direction of the arrow 12R, while the pedal 17 always maintains the same posture. Rotates relative to the crank arm 15 in the direction of the arrow 17R. Accordingly, the toothed region 28b of the first gear 28 meshes with the bevel tooth portion 29b of the middle gear 29 to rotate the middle gear 29, and this rotation is transmitted to the final gear 24a meshed with the spur tooth portion 29s, so that the rotating rod 24 At the same time, the rotary slider 25 rotates in the direction of the arrow line 24L. In the above process, the toothless region 28a of the first gear 28 faces the bevel tooth portion 30b of the middle gear 30 and is in a non-meshing state, so that the middle gear that is reversely driven by the last gear 24b of the rotating rod 24. The rotation of 30 is not hindered.

  Thus, when the pedal 17 rotates from the state shown in FIG. 7 toward the state shown in FIG. 6, the rotary slider 25 rotates in the direction of the arrow 24L together with the rotary rod 24, and the crankshaft moves along the inner peripheral surface of the fixed arm 15b. Therefore, the movable arm 15a advances from the fixed arm 15b along the axis. As shown in FIG. 3, when the pedal 17 rotates to the foremost position (position at 3 o'clock indicated by a solid line in FIG. 3), the entire crank arm 15 is extended to the maximum.

  In this way, each time the crankshaft 12 rotates 180 degrees as the pedal 17 is depressed, the reversing mechanism 19 causes the rotating rod 24 in the movable arm 15a to rotate forward and backward, thereby causing a screw mechanism (male screw). Since the rotating rod 24 screwed with the fixed arm 15b via the portion 26 and the female screw portion 21) moves forward and backward in the axial direction within the fixed arm 15b, the entire crank arm 15 periodically expands and contracts in the rotational radius direction. . Therefore, in the rotation range where a large leg force is applied when the pedal 17 is depressed (range around 3 o'clock shown in FIG. 3), the crank arm 15 is kept in the extended state, and the rotation range where almost no leg force is applied (around 9 o'clock shown in FIG. 3). If the reversing mechanism 19 is set so that the crank arm 15 is kept in the contracted state, the burden of leg force can be reduced.

  Further, the bicycle drive structure 10 of the present embodiment includes a rotating rod 24 that is rotatably held in the movable arm 15a and screwed to the fixed arm 15b, and a rotating rod 24 according to the rotation of the crankshaft 12. By providing the reverse rotation mechanism 19 for normal rotation and reverse rotation, a chain that easily stretches over a long period of use, a rail or a roller that causes wear, and the like are unnecessary, and therefore, it has excellent durability.

  Furthermore, in the bicycle drive structure 10, the reversing mechanism 19 can mesh with the first gear 28 that rotates in conjunction with the rotation of the pedal 17 and the first gear 28 at a position 180 degrees across the rotation center of the first gear 28. Two middle gears 29, 30 and two final gears 24a, 24b provided on the rotating rod 24 in mesh with the middle gears 29, 30, respectively, and the rotational direction of the gear surface of the first gear 28 An area of less than 180 degrees along the axis is a toothed area 28b that can be meshed, and the remaining area (area indicated by arrow 28R: for example, an area that exceeds 180 degrees and is less than 190 degrees) cannot be meshed 28a.

  Thus, since the intermediate gears 29 and 30 are interposed between the first gear 28 and the final gears 24a and 24b, by changing the gear ratio of these gears 28, 24a, 24b, 29 and 30, It is possible to finely change the amount of rotation of the rotating rod 24 while the pedal 17 rotates 180 degrees. Therefore, the degree of freedom in design when setting the expansion / contraction amount of the crank arm 15 that expands and contracts by the rotation of the rotating rod 24 is also high.

  Next, a second embodiment of the present invention will be described based on FIG. FIG. 12 is a sectional view showing a bicycle drive structure according to the second embodiment. In FIG. 11, the portions denoted by the same reference numerals as those in FIGS. 1 to 10 are portions having the same functions as the components of the bicycle drive structure 10 described above, and the description thereof is omitted.

  In the bicycle drive structure 40 shown in FIG. 11, the reversing mechanism 39 meshes with the first-stage gear 28 that rotates in conjunction with the rotation of the pedal 17 and the first-stage gear 28 at symmetrical positions across the rotation center of the first-stage gear 28. Two final gears 37 and 38 provided on the rotating rod 24 in a possible state are provided. A base end portion of the pedal shaft 17 a of the pedal 17 is pivotally supported by the movable arm 15 a via a bearing 35. In the present embodiment, the first gear 28 interlocked with the pedal shaft 17a is set in a state in which the toothless region 28a faces upward and the toothed region 28b faces downward, unlike the state shown in FIG. .

  With such a configuration, each time the pedal rotates 180 degrees with respect to the movable arm 15a, the first stage gear 28 also rotates 180 degrees, and the toothed region 28b of the gear surface of the first stage gear 28 is provided on the rotary rod 24. Since the two final gears 37 and 38 are alternately meshed, the rotating rod 24 repeats normal rotation and reverse rotation every time the pedal rotates 180 degrees. That is, the rotating rod 24 is rotated forward and backward by alternately engaging the toothed region 28b of the first gear 28 with the two final gears 37 and 38, so that the reversing operation is reliably performed according to the rotation of the pedal 17. It can be done and has excellent durability.

  Further, the reversing mechanism 39 has a simple structure including the first-stage gear 28 and the two final-stage gears 37 and 38, and at least a part of the first-stage gear 28 can be disposed in the movable arm 15a. Therefore, it is possible to reduce the size and weight. Other structures and functions are the same as those of the bicycle drive structure 10 described above.

  Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a partially omitted side view of a bicycle using the bicycle drive structure according to the third embodiment of the present invention, and FIG. 14 is a schematic view showing the function of the bicycle drive structure shown in FIG. In FIGS. 13 and 14, the parts denoted by the same reference numerals as those in FIGS. 1 to 10 are parts having the same functions as the constituent parts of the bicycle drive structure 10 described above, and the description thereof is omitted.

  As shown in FIGS. 13 and 14, the automobile drive structure 50 used in the bicycle BY has a wire 49 and a plurality of pulleys 45 and 46 as pedal holding means for preventing the right pedal 17 and the left pedal 18 from slipping. , 47 are provided. Both ends of the wire 49 are engaged with connecting portions 17c and 18c provided on the rotating portion 17b of the right pedal 17 and the rotating portion 18b of the left pedal 18 via springs 49s. The plurality of pulleys 45, 46, and 47 are pivotally supported by a part of the bicycle BY so as to hold the central portion of the wire 49 so as to be movable. The two pulleys 45 and 46 are rotatably attached to a support shaft 43 disposed coaxially with the rear wheel axle on the left and right sides of the rear wheel axle (not shown) of the bicycle BY, and a column 42 that supports the saddle 41 and a rear side. A pulley 47 is rotatably attached to a support shaft 48 provided near the upper end of a support member 44 that connects the wheel axle. Furthermore, as shown in FIG. 14, the wire 49 is stretched around the two pulleys 45 and 46 and the one pulley 47 so as to form a substantially W shape.

  With such a configuration, the right pedal 17 and the left pedal 18 are restrained by the wire 49, so that the left and right pedals 18 and 17 are idled while stopped or parked, and the crank arm 15 set in advance is set. , 16 can be prevented from breaking the regularity of the rotational motion and the expansion and contraction motion. On the other hand, as the left and right pedals 18 and 17 are cranked, the wire 49 reciprocates in the longitudinal direction via the pulleys 45, 46 and 47, so that there is no problem in the stepping operation of the left and right pedals 18 and 17 during travel. .

  Further, since springs 49 s are arranged between both ends of the wire 49 and the connecting portions 17 c and 18 c of the right pedal 17 and the left pedal 18, the right pedal 17 and the left pedal 18 are against the tension of the wire 49. And can be rotated slightly. Accordingly, it is possible to cope with a change in posture of the left and right pedals 18 and 17 that is required when the vehicle is depressed during traveling. In this embodiment, the wire 49 is used as a flexible tension transmission member, but the present invention is not limited to this, and for example, a chain, a wire, a string-like body, or the like can also be used. Further, since the positions of the pulleys 45, 46, 47 are not limited, the pulleys 45, 46, 47 can be attached to a place other than the position shown in FIG.

  The present invention can be widely used as a drive mechanism for various bicycles such as light vehicles, utility vehicles, and sports vehicles.

It is a top view which shows the drive structure for bicycles which is 1st Embodiment of this invention. It is a right view of the drive structure for bicycles shown in FIG. It is a side view which shows the expansion-contraction state of the right pedal of the drive structure for bicycles shown in FIG. It is the schematic which shows the rotation locus | trajectory of the right pedal shown in FIG. FIG. 2 is an exploded sectional view showing a part of the bicycle drive structure shown in FIG. 1. FIG. 2 is a cross-sectional view showing a state where a right crank arm is extended in the bicycle drive structure shown in FIG. 1. It is sectional drawing which shows the state which the crank arm shown in FIG. 6 contracted. It is sectional drawing in the AA of FIG. It is sectional drawing in the BB line of FIG. It is sectional drawing in the CC line of FIG. It is the figure which looked at the first stage gear shown in FIG. 6 from the bearing side. It is sectional drawing which shows the drive structure for bicycles which is 2nd Embodiment of this invention. It is a partially omitted side view of a bicycle using a bicycle drive structure according to a third embodiment of the present invention. It is the schematic which shows the function of the drive structure for bicycles shown in FIG.

Explanation of symbols

10, 40, 50 Bicycle drive structure 11 Bottom bracket 12 Crankshaft 13 Chain ring 14 Chain 15, 16 Crank arm 15a, 16a Movable arm 15b, 16b Fixed arm 15c, 22 Groove 15d Recess 15s Through hole 15t Locking groove 15x Base Wall portion 17 Right pedal 18 Left pedal 17a, 18a Pedal shaft 17b, 18b Rotating portion 17c, 18c Connection portion 19 Reversing mechanism 19a, 20a Cover 21 Female thread portion 23 Ball 24 Rotating rod 24a, 24b, 37, 38 Final gear 24f Expanded portion 25 Rotating slider 26 Male screw portion 27 Projection portion 28 First gear 28a Toothless region 28b Toothed region 29, 30 Middle gear 29a, 30a Support shaft 29b, 30b Bevel tooth portion 29s, 30s Flat tooth portion 31, 35 Bearing 32 Nut 41 Dollar 42 struts 43 and 48 support shaft 44 rotational locus R traveling direction of the support member 45, 46, 47 pulley 49 wire 49s spring BY bicycle Q pedal

Claims (6)

A driving structure for a bicycle in which a crank arm periodically expands and contracts in the direction of the rotation radius as the pedal is depressed during traveling,
The crank arm is pivotally supported on the distal end side of the movable arm, a cylindrical fixed arm attached to the crankshaft, a cylindrical movable arm inserted in the fixed arm so as to be slidable in the axial direction. A pedal, a rotating rod rotatably held on a substantially axial center of the movable arm, a screw mechanism for screwing the rotating rod and the fixed arm, and the crankshaft as the pedal is depressed. A bicycle drive structure, comprising: a reversing mechanism for rotating the rotating rod forward and reverse each time the motor rotates 180 degrees.   As the reversing mechanism, the first stage gear that rotates in conjunction with the rotation of the pedal, and two rotating gears provided on the rotating rod in a state of being able to mesh with the first stage gear at symmetrical positions across the rotation center of the first stage gear. A final gear is provided, and an area of less than 180 degrees along the rotation direction on the gear surface of the initial gear is set as a toothed area that can be meshed, and the remaining area is a non-meshable toothless area. Bicycle drive structure.   As the reversing mechanism, a first-stage gear that rotates in conjunction with the rotation of the pedal, two middle-stage gears that can mesh with the first-stage gear at positions 180 degrees across the rotation center of the first-stage gear, and the middle-stage gear Two final gears provided on the rotating rod in a state of meshing with each other, and a region of less than 180 degrees along the rotation direction on the gear surface of the first gear is set as a toothed region capable of meshing, and the remaining The bicycle drive structure according to claim 1, wherein the region is a toothless region incapable of meshing.   The bicycle drive structure according to any one of claims 1 to 3, further comprising pedal holding means for keeping the posture of the pedal substantially constant.   As the pedal holding means, a flexible tension transmitting member having both ends locked to the left and right pedals, and a pivotable shaft on a part of the bicycle to hold the tension transmitting member movably The bicycle drive structure according to claim 4, further comprising a supported pulley.   The bicycle drive mechanism according to claim 4, wherein a weight is provided at a position lower than a rotation center of the pedal as the pedal holding means.

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