JPH0796880A - Power device for engine-powered bicycle - Google Patents

Abstract

PURPOSE:To smoothly start an engine-powered bicycle with a simple and small power device by pulling a start lever so as to engage a one-way clutch in order to couple the output shaft of a transmission with a final stage spur gear, thereby it is possible to start an engine with the use of a depressing force of a bell crank. CONSTITUTION:When an engine-powered bicycle runs by the power of an engine, a pedal is depressed so as to run the bicycle. In this condition, a start lever is pulled so as to engage a jaw clutch 118 in order to transmit a power from a pedal crankshaft 11 to a large diameter spur gear 110 through a free-wheel 116, and a speed reduction shaft 109. Then, it is transmitted to a small bevel gear shaft 95 in a centrifugal automatic clutch 82 through a speed reduction part, and further, it is transmitted to the crank shaft 83 through a one-way clutch 100 and an extension shaft 90 so as to start the engine. After the engine is started, the start lever is returned so as to disengage the jaw clutch 18. A throttle valve is opened so as to increase the sped of the engine in order to engage a centrifugal automatic clutch 92, and accordingly, the power of the engine is transmitted to a rear wheel through a drive sprocket 114.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power unit for a motor-operated bicycle in which an engine is started by depressing a pedal crank.

[0002]

2. Description of the Related Art A conventional power unit for a bicycle with a motor is shown in FIG.
9 will be described with reference to FIG. 9. Reference numeral 1 in FIG. 6 is a bicycle-type vehicle body frame, and a head pipe 2 at the front end thereof has a front fork 4 pivotally supporting a front wheel 3.
A single down tube 5 extending rearward and downward is connected to the head pipe 2, and a saddle tube 7 extending upward via a bracket 6 is connected to a rear end portion of the down tube 5. A saddle 8 is supported on the upper end of the saddle tube 7.

The bracket 6 supports an engine unit 9 which will be described later.
Rear arms 10, 10 extending rearward are attached to the left and right side surfaces of the. A rear wheel 11 is supported between the rear ends of the rear arms 10 and 10.
Left and right backstays 12, 12 extend obliquely forward from the rear end portions of the backstays 0, 10.
The tip ends of 2, 2 are connected to the upper end of the saddle tube 7.

Reference numeral 13 is a rear carrier installed above the rear wheel 11, 68 is a fuel tank, and 69 is an electrical component case containing a battery and other electrical components. As shown in FIG. 8, the engine unit 9 includes a forced-air-cooled two-cycle engine 14 at the rear end of the rear wheel 11 side. The engine 14 has a crankcase 15 in the longitudinal direction of the vehicle body. A horizontally mounted cantilevered crankshaft 16 is pivotally supported. A flywheel magneto 17, a centrifugal automatic clutch 18, and a planetary gear reducer 19 are coaxially connected in this order to the front end of the crankshaft 16.

The periphery of the flywheel magneto 17, the clutch 18 and the speed reducer 19 is covered with a hollow cylindrical casing 20 connected to the crankcase 15, which constitutes a substantially cylindrical engine unit 9. ing. The planetary gear type speed reducer 19 constitutes, for example, a primary speed reducer 53 having a speed reduction ratio of 5: 1, and reduces the rotation of the crankshaft 16 to ⅕ and outputs it to the output shaft 44. ing.

A cylinder 21 is provided on the lower surface of the crankcase 15, and an air shroud 22 covering the cylinder 21 is surrounded by a fan 23 provided on the rear surface of the flywheel magnet 17 so that the outside air is blown out. Is taken in and the area around the cylinder is forcibly cooled. Further, a carburetor 26 is connected to an intake port 24 opened at the rear end surface of the crankcase 15 via a reed valve 25. The carburetor 26 is inside an air cleaner case 27 connected to the rear end of the crankcase 15. Is in communication with. And inside the air cleaner case 27,
The element 28 divides the first intake chamber 29 connected to the outside and the second intake chamber 30 connected to the carburetor 26 from the intake hole 15a on the rear surface of the crankcase 15 to the first intake chamber 30.
The outside air sucked into the intake chamber 29 of the first filter passes through the element 28, is filtered, then flows into the second intake chamber 30, and is sucked into the carburetor 26 from here.

The exhaust pipe 31 extending rearward from the rear surface of the cylinder 21 is connected to a silencer 32 attached to one rear arm 10. On the other hand, a bearing housing 20a that pivotally supports the output shaft 44 of the speed reducer 19 is attached to the front end opening of the casing 20, and the lower end of the bearing housing 20a is attached to the lower surface on the front end side of the casing 20. A gear case 33 for taking out is integrally formed. The gear case 33 is located substantially in the center of the vehicle body below the saddle 8, and a pedal crankshaft 34 is inserted in the gear case 33 in the left-right direction as shown in FIG. The gear case 33 is rotatably supported via the gear case 33.

Both ends of the pedal crank shaft 34 project outward from both sides of the gear case 33, and the pedals 36, 36 are provided at both outer ends of the pedal crank shaft 34.
Pedal cranks 37, 37 having 36 are mounted. A reduction gear shaft 38 serving as a drive shaft is coaxially supported on the outer periphery of the pedal crank shaft 34 on the one end side, and between the inner periphery of the reduction gear shaft 38 and the outer periphery of the pedal crank shaft 34. A one-way clutch 39 that transmits only the rotation from the pedal crankshaft 34 side to the reduction gear shaft 38 side is interposed in the.

A boss portion 41 of a drive sprocket 40 is spline-engaged with the outer periphery of the reduction gear shaft 38, and a chain 43 is provided between the drive sprocket 40 and the free sprocket 42 on the rear wheel 11 side. Suspended. Below the front end of the engine unit 9, an intermediate shaft 45 for transmitting the engine power output from the engine to the output shaft 44 to the reduction gear shaft 38 is arranged. A bearing 47 is provided in a tubular portion 46 that connects the gear case 33 and the bearing housing 20a.
It is pivotally supported via 47.

A reduction large diameter helical gear 48 attached to one end of the intermediate shaft 45 meshes with a reduction small diameter spur gear 49 at the front end of the output shaft 44. The reduction small diameter gear 50 formed on the other end outer peripheral surface on the opposite side meshes with the internal teeth 51 of the inner end surface of the reduction gear shaft 38, and by these meshing, for example, a secondary reduction gear having a reduction ratio of 12: 1. The output shaft 44
The rotation of is reduced to 1/12 and transmitted to the reduction gear 38. In this conventional example, the output shaft 44 and the intermediate shaft 45 constitute a power transmission mechanism,
The total reduction ratio in the meantime is 60: 1.

The output shaft 44 and the reduction small diameter spur gear 49 are provided.
A one-way clutch 52 that transmits rotation only from the output shaft 44 side to the reduction small diameter spur gear 49 side is interposed between and. In addition, a hollow cylindrical starting rotary shaft 55a parallel to the output shaft 44 is provided at the upper end of the bearing housing 20a.
Is pivotally supported. A slider 56 is fitted in the front end opening of the starting rotary shaft 55a.
A driven shaft 55b is coaxially fitted in the rear end opening of the slider 5a, and a small starting gear 57 is formed on the outer peripheral surface of the slider 56.
The boss portion 57a is rotatably mounted.

The boss portion 57a of the starting small gear 57 is
While straddling the front end of the starting rotary shaft 55a, the inner peripheral surface thereof is spline-engaged with the outer peripheral surface of the starting rotary shaft 55a, so that the starting rotary shaft 55a rotates integrally. There is. The slider 56 is interlocked with a starting lever (not shown) via a spring 58 and a wire 59 passing through the starting rotary shaft 55. When the starting lever is operated to slide the slider 56 rearward. The small starting gear 57 is adapted to mesh with the large starting gear 60 integrated with the reduction small diameter spur gear 49 against the biasing force of the return spring 70.

When the slider 56 is slid, the coil spring 61 stretched between the slider 56 and the driven shaft 55b is compressed, and the compression force causes the driven shaft 5 to move.
5b slides integrally toward the rear. A boss portion 62a of the starting small diameter gear 62 is rotatably mounted on the outer peripheral surface of the driven shaft 55b, and an interlocking shaft 63 is coaxially mounted on the boss portion 62a. The front end of 63 enters into the rear end opening of the starting rotary shaft 55a and is spline-engaged with the inner peripheral surface thereof.

The boss portion 62a of the small diameter gear 62 for starting
A one-way clutch 66 that transmits rotation only from the interlocking shaft 63 to the starting small diameter gear 62 is interposed between the interlocking shaft 63 and the interlocking shaft 63, and when the driven shaft 55b is slid backward,
The starting small diameter gear 62 is adapted to mesh with the starting large diameter gear 65 mounted between the flywheel magneto 17 and the clutch 19 against the biasing force of the return splatling 64. Gears 57, 62, starting large gears 60, 65, starting rotating shaft 55a, interlocking shaft 63
Further, the one-way clutch 66 constitutes a bypass path that bypasses the primary reduction gear unit 53.

Next, the operation of the conventional power unit for a bicycle with a motor shown in FIGS. 6 to 9 will be specifically described. (1) When stepping on the pedals 36, 36 to run as a normal bicycle, the rotational driving force transmitted to the pedal crank shaft 34 via the pedal cranks 37, 37 is transmitted to the reduction gear via the one-way clutch 39. It is transmitted to the shaft 38, and from here, the drive sprocket 40 → chain 443.
→ Transmitted to the rear wheel 11 via the free sprocket 42.

At this time, the reduction gear shaft 38 is the intermediate shaft 4
5 is linked to the output shaft 44 via the intermediate shaft 45
When the rotational force is input from the side, the one-way clutch 5
By the action of 2, the reduction small diameter spur gear 49 idles on the output shaft 44, and the rotation is not transmitted to the output shaft 44. Therefore, the primary reduction portion 53 is not dragged and rotated, and the pedal drive is not hindered. Done. (2) When traveling by engine power, the engine power decelerated to 1/5 by the output shaft 44 and taken out is transmitted to the reduction small diameter spur gear 49 via the one-way clutch 52, and Further deceleration 1 /
It is decelerated to 12, transmitted to the reduction gear shaft 38, and thereafter transmitted to the rear wheel 11 via the same route as described above.

In the two running states, the starting large diameter gear 60, the starting small diameter gear 57, the starting large diameter gear 65 and the starting small gear 62 which are integrated with the reduction small diameter gear 49 operate the starting lever. Unless they are engaged, power is not transmitted to the bypass 67. (3) On the other hand, when the engine is started, the pedal cranks 37, 37 are used as in the case of traveling as the bicycle.
By depressing, the reduction small diameter spur gear 49 is artificially forced to rotate. Then, in this state, the starter lever is operated to slide the slider 56 rearward to rotate the starter rotating shaft 55a and the coil spring 61.
The driven shaft 55b is slid rearward by the compressive force of, and the starting small diameter gear 62 on the outer peripheral surface thereof is meshed with the starting large diameter gear 65, and the starting large diameter gear 60 is formed via the reduction small diameter spur gear 49. The extracted rotational force is applied to the small diameter gear 57 for starting.
Is transmitted directly to the crankshaft 16 of the engine 14 through the starting rotary shaft 55a, the interlocking shaft 63, the one-way clutch 66, the starting small diameter gear 62, and the starting large gear 65.

When the engine 14 starts, the starting small diameter gear 62 rotates at a higher speed than the interlocking shaft 63, but the interlocking shaft 63 is provided between the starting small diameter gear 62 and the interlocking shaft 63. Since the one-way clutch 66 that allows only the rotation from the side is interposed, when the rotational force is input from the starting small diameter gear 62 side, the starting small diameter gear 62 idles on the interlocking shaft 63. , The power is not transmitted to the interlocking shaft 63.

Thus, at the time of starting, the pedal crankshaft 3
The rotational force transmitted from the fourth side to the output end of the output shaft 44 is directly transmitted to the crankshaft 16 via the bypass route 67 that bypasses the primary reduction gear unit 53, so that the primary reduction gear unit 53
Does not rotate due to being dragged, and as a result, the speed increasing ratio is 6 when viewed from the pedal crankshaft 34 side at the time of starting.
It changes from 0: 1 to 12: 1, and the pedal drive is lightened accordingly.

[0020]

The conventional power unit for a motorized bicycle shown in FIGS. 6 to 9 is equipped with an engine and can be driven by manpower and by power. In order to perform power running, when starting the engine, with the bicycle stopped, pull the starter grip with your hand or kick the kick lever with your foot to move the engine crankshaft. The pedal crankshaft is rotated either by rotating or pedaling with the foot, and the engine crankshaft is rotated while the bicycle is running, but from the viewpoint of convenience, the method of starting with the pedal is superior. As described above, while the engine is started by depressing the pedal as described above, the engine crankshaft is rotated through a bypass path that does not pass through a part of the speed reducer to start the engine.

In this case, however, the advantage of requiring less pedaling force is that it has the problem that the structure becomes complicated because the detour route is added. The present invention is proposed in view of the above-mentioned problems, and an object of the present invention is to simplify and downsize the device and reduce the manufacturing cost. It can also be mounted on a bicycle body in a normal wheel space. Further, the influence on the maneuverability can be reduced. Further, it is a point to provide a power unit for a bicycle with a motor which can improve power transmission efficiency.

[0022]

In order to achieve the above object, the present invention is a power unit for a motor-powered bicycle that is capable of manpowered traveling and engine-powered traveling, and is mounted on the vehicle body behind the front wheels. An engine having an engine crankshaft protruding rearward of the vehicle body, a speed reducer including an input shaft, a set of bevel gears, a plurality of sets of spur gears, and a hollow output shaft, an input shaft of the speed reducer, and the engine crankshaft. A centrifugal automatic clutch that connects the drive shaft, a drive sprocket that is connected to the hollow output shaft of the speed reducer, and a pedal crankshaft that penetrates the hollow output shaft of the speed reducer, and the pedal crankshaft and the drive sprocket A free wheel that transmits rotation only from the pedal crankshaft side to the drive sprocket side is interposed between and, and is supported by the hollow output shaft and the hollow output shaft of the speed reducer. A one-way clutch that transmits rotation only from the final stage spur gear side to the hollow output shaft side is interposed between the final stage spur gear of the speed machine to form a meshing clutch. Is provided on the vehicle body side so as to disengage and engage the engagement clutch by moving in the direction, and the rotation is transmitted only from the pedal crankshaft side to the engine crankshaft side between the input shaft and the output shaft of the centrifugal automatic clutch. It has a directional clutch.

Further, the present invention relates to a power unit for a bicycle with a prime mover capable of manpowered driving and power running by an engine, wherein the engine is mounted on a vehicle body rearward of the front wheels and has an engine crankshaft projecting rearward of the vehicle body. A reduction gear composed of an input shaft, a set of bevel gears, a plurality of sets of spur gears, and a hollow output shaft, a centrifugal automatic clutch connecting the input shaft of the reduction gear and the engine crankshaft, and a reduction gear of the reduction gear. A drive sprocket connected to the hollow output shaft and a pedal crankshaft penetrating the hollow output shaft of the speed reducer, and only between the pedal crankshaft side and the drive sprocket side between the pedal crankshaft and the drive sprocket. A free wheel that transmits rotation is interposed, and rotation is transmitted only from the spur gear side to the reduction shaft side between the reduction shaft of the reduction gear and the spur gear that meshes therewith. A clutch push rod for mounting and disengaging the spur gear of the reduction gear by axially moving the spur gear of the speed reducer is provided on the vehicle body side, and an input shaft and an output shaft of the centrifugal automatic clutch are provided. And a one-way clutch that transmits rotation only from the pedal crankshaft side to the engine crankshaft side.

In the power unit for the bicycle with the motor,
The speed reducer and the engine may be arranged spirally around the pedal crankshaft, and the speed reduction shaft and the engine may be changeable according to the structure of the vehicle body. In the power unit for a motor-powered bicycle, a flywheel magneto that serves as a power source for a bicycle lamp or the like may be arranged between the engine crankshaft and the centrifugal automatic clutch.

[0025]

The power unit for a motorbike according to the present invention is constructed as described above, and when driving manually, the rotary driving force generated on the pedal crankshaft by stepping on the pedal is converted into freewheel → drive sprocket → chain → free sprocket. To the rear wheels. This rotational driving force is cut off by the one-way clutch interposed between the hollow output shaft of the reduction gear and the final stage spur gear, and is not transmitted to the engine side. When the engine is running, pull the start lever and step on the pedal. When the starter lever is pulled, the one-way clutch is engaged, the hollow output shaft of the speed reducer and the final stage spur gear are connected, and the bicycle travels in the same manner as when driving manually, and the rotational driving force of the pedal crankshaft meshes. It is transmitted to the final stage spur gear via the clutch, and further, the crankshaft of the engine is rotated via the one-way clutch interposed between the speed reducer and the centrifugal automatic clutch to start the engine. When the engine starts, the input shaft of the centrifugal automatic clutch rotates at high speed, and the one-way clutch interposed in the centrifugal automatic clutch is disengaged. Here, the starting lever is returned to disengage the dog clutch. Next, open the throttle to increase the engine speed, the centrifugal automatic clutch will be activated, the rotational drive force from the engine will be decelerated through the reducer section and transmitted to the drive sprocket, and then the chain → free sprocket. After that, it is transmitted to the rear wheels. The rotation of the rear wheel at this time is blocked by the free wheel and is not transmitted to the pedal crankshaft.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power unit for a motorbike according to the present invention will be described below with reference to FIGS. FIG. 1 shows an outline of a bicycle equipped with this power unit. 1 is a bicycle body frame, 2 is a head pipe, 3 is a front wheel, 4 is a front fork, 5 is two down tubes, and 6 is a bracket. , 7 is a saddle tube, 8 is a saddle, 10 is two rear arms, 11 is a rear wheel, 12 is two backstays,
Reference numeral 31 is an exhaust pipe, 32 is a silencer, 36 is a pedal, 37 is a pedal crank, 42 is a free sprocket, 43 is a chain, 68 is a fuel tank, 80 is an engine unit (driving device) suspended on the bracket 6, and 85 is a throttle. ,
86 is a starting lever, 114 is a drive sprocket, and 115
Is the pedal crankshaft. Since these parts 1 to 68 are the same as those in the conventional example, further description will be omitted.

FIG. 2 shows an essential part of the engine unit 80, and FIG. 3 is a cross-sectional plan view seen from the direction of arrow a in FIG.
The main part is shown in cross section, and the positions of the three shafts of the reduction gear are linearly extended. The engine unit 80 is
It consists of an engine part, a clutch part, and a speed reducer part.
The clutch part and the speed reducer part are integrally housed in a casing 81 that is connected to the engine part and can be divided into a plurality of parts.

In FIGS. 2 and 3, reference numeral 82 is a forced air cooling type 2.
The body of the cycle engine, 83 is its crankshaft, 84
Is a vaporizer, and 84a is an air cleaner. Reference numeral 90 denotes an extension shaft taperly coupled to the crankshaft 83, 91 is a coupling bolt for the crankshaft, 92 is a centrifugal automatic clutch, 93 is an input inner rotor of the centrifugal automatic clutch 92, and 92 is an output outer rotor. Is an output shaft integral with the outer rotor 94, and this output shaft 95 has a small bevel gear 96 at its rear end.
Is a small bevel gear shaft.

Reference numeral 97 is a contact piece pinned to the inner rotor 93, 98 is a sleeve, 99 is a bearing interposed between the casing 81 and the small bevel gear shaft 95, and 100 is between the sleeve 98 and the small bevel gear 95. Is a one-way clutch interposed between the inner rotor 93 and the sleeve 98.
It is screwed to 0 and is further fastened together with the bolt 91.

101 is a first reduction shaft orthogonal to the small bevel gear shaft 95, 102 is a large bevel gear fixed to one end of the first reduction shaft 101 and meshes with the small bevel gear 96, and 103 is the first reduction shaft 101. A small spur gear formed at one end of the first reduction shaft, a bearing rotatably supporting both ends of the first reduction shaft 101, a second reduction shaft 105 parallel to the first reduction shaft 101, and one end of the second reduction shaft 105. Fixed to the small spur gear 103 and meshing with the small spur gear 103, 107 is a small spur gear that is formed at one end of the second reduction shaft 105, and 108 rotatably supports both ends of the second reduction shaft 105. The bearing, 109 is a hollow third reduction shaft parallel to the second reduction shaft 105 and has a flange having a meshing claw 109a on its side surface, and 110 is a large-diameter spur gear (final stage spur gear). The gear 110 is the third reduction shaft 109.
Is fitted from the outside through a one-way clutch 111 and meshes with the small diameter spur gear 107. The large-diameter spur gear 110 includes a claw 110a and an annular groove 110b.

Reference numeral 112 denotes a bearing that rotatably supports both ends of the third reduction shaft 109, 113 is a disc-shaped bracket screwed to one end of the third reduction shaft, and 114 is a first bracket via the bracket 113. 3 is a drive sprocket attached to the reduction shaft 109. A pedal crankshaft 115 is rotatably fitted in the hollow third reduction shaft 109, and one end of the pedal crankshaft 115 is connected to the drive sprocket 114 via a freewheel (one-way ratchet clutch) 116. The other end of the pedal crankshaft 115 is connected and is rotatably supported by a bearing 117.

The above three reduction shafts 101, 105, 109
Are arranged in a spiral shape as shown in FIG.
The engine unit 80 is compact so that it can be easily attached to the bicycle body. Further, the arrangement of the reduction shaft and the engine can be changed around the pedal crank shaft 115 in accordance with the structure of the bicycle body. The nail 1
09a and the claw 110a form a part of the meshing clutch 118. Further, 119 is a clutch shift of the dog clutch 118, 120 is a crank type swing shaft, and 12 is fixed to the tip of the bend of the swing shaft, and the groove 1 of the large spur gear 110 is fixed.
10b is a pin fitted to the arm, 122 is an end ring having an arm, and 123 is a bifurcated joint pinned to the arm.

When the starting lever 86 (see FIG. 1) is operated, the bifurcated joint 123 swings the end ring 122 and the swing shaft 120 by the Bowden rope, and the pin 121 slides the large spur gear 110 in the axial direction to engage the mesh. Clutch 11
8 is removable. A pedal crank 37 having a pedal 36 is mounted on both ends of the pedal crank shaft 115, and a chain 43 is suspended between the drive sprocket 114 and the free sprocket 42 of the rear wheel 11.

The one-way clutch 100 transmits rotation only from the small bevel gear shaft 95 side to the crankshaft 83 side, and the one-way clutch 111 transmits rotation only from the large spur gear 110 side to the third reduction shaft 109 side. The free wheel (one-way ratchet clutch) 116 is connected to the pedal crankshaft 11
Rotation is transmitted only from the 5 side to the drive sprocket 114 side.

Next, the operation of the power unit for the motorbike shown in FIGS. 1 to 3 will be described in detail. (1) When traveling by human power, the pedal crank shaft 11 is depressed through the pedal crank 37 by stepping on the pedal 36.
5, the rotational driving force generated at that time is transmitted to the driving sprocket 114 via the free wheel 116,
Further, it is transmitted to the rear wheel 11 via the chain 43 → free sprocket 42. At this time, the drive sprocket 114
At the same time, the third reduction shaft 109 also rotates, but the rotational driving force is blocked by the one-way clutch 111 and is not transmitted to the engine side. In addition, the rotation of the rear wheel 11 is the free wheel 1
Since it is blocked by 16 and is not transmitted to the pedal crankshaft 115, the pedal can be stopped and placed. (2) When traveling with engine power, first pull the starting lever 86 while stepping on the pedal in the same manner as above,
Drive a bicycle. When the start lever 86 is pulled, the dog clutch 118 is engaged, and the rotational driving force of the pedal crankshaft 115 changes from the freewheel 116 to the drive sprocket 114.
→ Third reduction shaft 109 → Transmitted to the large diameter spur gear 110 via the meshing clutch 118, further transmitted to the small bevel gear shaft 95 of the centrifugal automatic clutch 92 via the reduction unit, and further transmitted to the one-way clutch 100 → Extension shaft 90. The engine 82 is transmitted to the crankshaft 83 and starts.

When the engine is started, the start lever 86 is returned and the dog clutch 118 is disengaged. When the engine 82 is started, the rotational speeds of the crankshaft 83 and the extension shaft 90 become higher than the rotational speed of the small bevel gear shaft 95, so the engagement is released by the one-way clutch 100, and the pedal crankshaft 115 side is disengaged. Not transmitted. Then the throttle 85
Open to increase the engine speed. Then,
The centrifugal automatic clutch 92 is inserted, the small bevel gear shaft 95 rotates, the first reduction shaft 101 is decelerated by the small bevel gear 96 and the large bevel gear 103, and further the small spur gear 103, the large spur gear 106, and the small spur gear. From 107 and spur gear 110,
The second deceleration shaft 105 and the third deceleration shaft 109 are decelerated, the rotational driving force is transmitted to the drive sprocket 114, and after that, it is transmitted to the rear wheels 11 as in the manual traveling.

In this case, the driving force of the engine is shut off by the freewheel 116 and the pedal crankshaft 1
15 is not transmitted, and even if the driving force from the pedal crankshaft 115 is generated, it is cut off by the one-way clutch 111 and is not transmitted to the engine side. Therefore, the pedal 36 can be used freely under the same conditions as when the engine is not used.

As shown in FIG. 4, the extension shaft 90 may be equipped with a buzzer, a direction indicator, and a flywheel magneto 130 that can be used for lighting. 130a, 130b
Indicates a rotor and a coil, respectively. Further, as shown in FIG. 5, instead of the mesh clutch 118 of FIG. 3, the mesh clutch 143 is provided between the first reduction shaft 101 and the second reduction shaft 142.
May be provided.

That is, the large diameter spur gear 141 is the second reduction shaft 1
42, a spur gear portion 141 meshing with a small spur gear 144
A is provided and the one-way clutch 140 is interposed between the second reduction shaft 142 and the second reduction shaft 142. One-way clutch 140
Transmits the rotation only from the large diameter spur gear 141 to the second reduction shaft side. A compression spring 145 is provided below the large spur gear 141, and is movable between a solid line position and a two-dot chain line position as shown in FIG.

The push rod 146 is connected to a lever 148 pivotally supported by a bracket 147 fixed to the casing 81, and a roller 149 is pivotally supported at the lower end thereof. The lever 148 is connected to the starting lever 86 by a wire or the like. When traveling by human power, the large diameter large spur gear 114 is pushed down by the push rod 146 to bring the large spur gear 141 and the small spur gear 144 into a non-engaged state by changing the position from the solid line position to the two-dot chain line.

When traveling by engine power, the large spur gear 141 is moved from the position indicated by the chain double-dashed line to the position indicated by the solid line, and the pedal is depressed to drive the bicycle. Then, when the engine is started, the large diameter spur gear 141 is moved from the solid line position to the two-dot chain position to transmit the power from the engine to the second reduction shaft 142 via the one-way clutch 140.

[0042]

The power unit for a motorbike according to the present invention is constructed as described above, and the following effects can be achieved. (1) The engine can be started while stepping on the pedal like a normal bicycle, and it has a simple structure in which only a few parts are added to the power transmission device for running with engine power. The device can be simplified and downsized, and the manufacturing cost can be reduced. (2) It is possible to arrange a plurality of reduction gear shafts in a spiral shape, which makes it possible to make a power unit including an engine compact, and to change the shape so that it can be easily attached to a bicycle body. Can be mounted on the vehicle body. Further, since the mass can be concentrated and the moment of inertia can be reduced, the influence on the maneuverability can be reduced. (3) Since bevel gears and spur gears with less slippage are used as reduction gears, power transmission efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a side view schematically showing an embodiment of a power unit for a motorbike according to the present invention.

FIG. 2 is a vertical cross-sectional side view showing details of the power plant.

3 is a cross-sectional plan view seen from the direction of arrow a in FIG.

FIG. 4 is a vertical cross-sectional side view showing an embodiment in which a flywheel magneto is mounted on the power plant.

FIG. 5 A cross-sectional plan view showing another embodiment of the power plant.

FIG. 6 is a side view of a conventional motorized bicycle. .

FIG. 7 is a bottom view seen from the direction of arrow b in FIG.

FIG. 8 is a cross-sectional plan view of the power transmission device.

9 is a cross-sectional bottom view taken along the line cc of FIG.

[Explanation of symbols]

1 vehicle body 80 power unit 82 engine 83 crankshaft 90 input shaft (extension shaft) 92 centrifugal automatic clutch 95 input shaft (small diameter bevel gear) 96, 102 one set of bevel gear 100 one-way clutch 103 spur gear of reduction gear 106 〃 107 〃 110 〃 109 Reducer hollow output shaft 110 Reducer large diameter spur gear (final stage spur gear) 110b Annular groove 111 One-way clutch 114 Drive sprocket 115 Pedal crankshaft 116 Freewheel 118 Interlocking clutch 119 Clutch approaching 146 Clutch push rod

Front page continuation (72) Inventor Kazuyuki Uenoyama No. 1 Takamichi, Iwazuka-cho, Nakamura-ku, Nagoya, Aichi Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works (72) Kenji Yamazaki 49, 399 Matsunaga-cho, Fukuyama-shi, Hiroshima Yamazaki Seisakusho Co., Ltd.

Claims (4)

[Claims] 1. A power unit for a bicycle with a prime mover capable of manpower running and power running by an engine, wherein an engine mounted on a vehicle body behind a front wheel and having an engine crankshaft projecting rearward of the vehicle body, and an input shaft. A reducer consisting of a set of bevel gears, a plurality of sets of spur gears, and a hollow output shaft, a centrifugal automatic clutch connecting the input shaft of the reducer and the engine crankshaft, and a hollow output shaft of the reducer. Has a drive sprocket connected to the pedal and a pedal crankshaft penetrating the hollow output shaft of the speed reducer, and transmits rotation only from the pedal crankshaft side to the drive sprocket side between the pedal crankshaft and the drive sprocket. The hollow output shaft of the speed reducer and the final stage spur gear of the speed reducer supported by the hollow output shaft are inserted from the same end stage spur gear side. A one-way clutch that transmits rotation only to the output shaft side is interposed to form a meshing clutch, and a clutch shifter that displaces the meshing clutch by moving the final stage spur gear of the reduction gear in the axial direction is provided on the vehicle body side. A power unit for a motorbike according to claim 1, wherein a one-way clutch that transmits rotation only from the pedal crankshaft side to the engine crankshaft side is interposed between the input shaft and the output shaft of the centrifugal automatic clutch. 2. A power unit for a bicycle with a prime mover capable of manpower running and power running by an engine, wherein an engine is mounted on a vehicle body behind the front wheels and an engine crankshaft is projected rearward of the vehicle body, and an input shaft is provided. A reducer consisting of a set of bevel gears, a plurality of sets of spur gears, and a hollow output shaft, a centrifugal automatic clutch connecting the input shaft of the reducer and the engine crankshaft, and a hollow output shaft of the reducer. Has a drive sprocket connected to the pedal and a pedal crankshaft penetrating the hollow output shaft of the speed reducer, and transmits rotation only from the pedal crankshaft side to the drive sprocket side between the pedal crankshaft and the drive sprocket. A freewheel, and a one-way clutch that transmits rotation only from the spur gear side to the reduction shaft side between the reduction shaft of the reduction gear and the spur gear meshing with the reduction shaft. A clutch push rod for mounting and disengaging the spur gear of the speed reducer in the axial direction to attach / detach the mesh clutch, and the clutch push rod is provided between the input shaft and the output shaft of the centrifugal automatic clutch. A power unit for a motorized bicycle, wherein a one-way clutch that transmits rotation only from the pedal crank shaft side to the engine crank shaft side is interposed. 3. The reduction gear and the engine are arranged spirally around the pedal crankshaft, and the reduction shaft and the engine can be changed and arranged according to the structure of the vehicle body. 2. A power unit for a bicycle with a motor according to 2. 4. A flywheel magneto that serves as a power source for a bicycle lamp or the like is provided between the engine crankshaft and the centrifugal automatic clutch.
The power unit of the described bicycle with a motor.