JPS6189192A - Power transmission gear for motor bicycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a motorized bicycle whose engine is started by depressing a pedal crank, and particularly to a power transmission device thereof.

[Technical background of the invention and its problems] - In a motorized bicycle with an engine mounted on a bicycle-type body frame, when running on engine power, the power extracted to the crankshaft is usually decelerated in multiple stages. The signal is transmitted to the drive shaft in a state in which the signal is adjusted, and is further transmitted to the rear wheels via an appropriate transmission means.

In such motorized bicycles, the engine is started by using a pedal crank, that is, by rotating the drive shaft with the pedal crank, and transmitting the power to the crankshaft through the aforementioned multi-stage reduction section. If this is done, the rotation of the drive shaft will be accelerated at the time of starting, which will cause problems such as increased pedal drive.

Therefore, it is conceivable to provide a path that directly transmits the rotational driving force of the drive shaft to the crankshaft without passing through the deceleration part at the time of starting, but if this is done, the power transmission device will not work at all when driving with engine power. Since another path is added, the structure of the power transmission device becomes complicated and costs increase, and the entire device becomes heavy and large.Therefore, there is a desire to make the engine area as compact as possible. This is not desirable for motorized bicycles.

[Purpose of the invention]

The present invention was made based on these circumstances, and
To provide a power transmission device for a motorized bicycle, which allows light pedal driving when starting an engine, makes the entire device smaller and lighter, and simplifies the structure.

[Summary of the invention]

That is, the power transmission device of the present invention that achieves the above object bypasses a part of the reduction unit to transmit the rotational driving force of the drive shaft at the time of engine startup in which power is transmitted from the drive shaft side to the crankshaft side. The feature is that a detour route is provided to transmit the information to the crankshaft side.

[Embodiments of the invention]

The present invention will be described below based on an embodiment shown in the drawings.

Reference numeral 1 in FIG. 3 denotes a bicycle-type body frame, and a front foot 4 on which a front wheel 3 is pivotally supported is pivotally supported on a head pipe 2 at the front end of the frame. A down tube 5 extending rearward and downward is connected to the head vibe 2, and a saddle tube 7 extending upward is connected to the rear end of the down tube 5 via a bracket 6. A saddle 8 is supported at the upper end of the saddle tube 7. Further, an engine unit 9, which will be described later, is supported by the bracket 6, and rear arms 10 and 10 extending rearward are provided on the left and right sides of the engine unit 9.
is installed. A rear wheel 11 is supported between the 1st and 2nd ends of the rear arms 10, 10, and left and right backstays 12.12 are led out diagonally forward from the rear ends of the rear arms 10.10. The leading ends of these backstays 12 and 12 are connected to the upper end of the saddle tube 7.

Note that reference number 13 in FIG. 3 indicates a carrier installed above the rear wheel 11.

By the way, as shown in FIG. 1, the engine unit 9 is equipped with a forced air-cooled two-stroke engine 14 at the rear end on the rear wheel 11 side. A cantilevered crankshaft 16 placed horizontally along the direction is pivotally supported. A flywheel magnet is attached to the front end of the crankshaft 16.
17, a centrifugal automatic clutch 18 and a planetary gear reducer 19 are coaxially connected in this order. These flywheel magneto-11, clutch 18 and reducer 1
The periphery of the engine unit 9 is integrally covered by a hollow cylindrical casing 20 that is connected to the crankcase 15, thereby creating a substantially cylindrical engine unit 9. The above-mentioned 'Fi star gear type reduction gear (geo 19) has a primary reduction part 53 with a reduction ratio of 5:1 at the bottom of the groove, and reduces the rotation of the crankshaft 16 to 115 and outputs it to the output shaft 44. A cylinder 21 is protruded from the lower surface of the crankcase 15, and a fan 23 protruding from the rear surface of the flywheel magneto 17 is installed in an air shroud 22 surrounding the cylinder 21. The outside air taken in is blown, and the area around the cylinder is forcibly cooled.Furthermore, an air intake port 24, which has v: and j:0 on the end face of the crankcase 15, is connected through a reed valve 25. A vaporizer 26 is connected to the
This carburetor 26 is communicated with an air cleaner case 27 connected to the rear end of the crankcase 15. The inside of the air cleaner case 27 is divided by the element 28 into a first intake chamber 29 connected to the outside air and a second intake chamber 30 connected to the carburetor 2G. The outside air sucked into the intake chamber 29 of No. 1 passes through Niremen 1 to 28! ! After being evaporated, it flows into the second intake chamber 30 and is sucked into the vaporizer 26 from there.

Note that an exhaust pipe 31 led out rearward from the rear surface of the cylinder 21 is connected to a silencer 32 attached to one rear arm 10.
It is connected to the.

On the other hand, at the front end opening of the casing 20, a reduction gear 1 is provided.
A bearing housing 20a that pivotally supports the output shaft 44 of No. 9 is attached, and a gear case 33 that projects from the lower surface of the front end side of the casing 20 is integrally formed at the lower end of the bearing housing 20a. The gear case 33 is located just below the saddle 8 [approximately at the center of the I body;

As shown in FIG. 2, a pedal crankshaft 34 is inserted through the pedal crankshaft 34 in the left-right direction and is rotatably supported via bearings 35 and 35. Both ends of the pedal crankshaft 34 are led out from both sides of the gear case 33, and pedal cranks 37, 37 with pedals 36, 36 are attached to both ends.
is installed. A reduction gear shaft 38 serving as a drive shaft is coaxially supported on the outer periphery of one end of the pedal crankshaft 34, and there is a gap between the inner periphery of the reduction gear shaft 38 and the outer periphery of the pedal crankshaft 34. is pedal crank f@3
A one-sided clutch 39 is interposed that allows only power transmission from the 4 side to the reduction gear shaft 38 side. Further, a boss portion 41 of the drive sprocket 40 is provided on the outer periphery of the reduction gear shaft 38.
is spline engaged, and this drive sprocket 4
A chain 43 is wound L times between the rear wheel 11 and the free sprocket 42 of the rear wheel 11.

An intermediate shaft 45 that transmits the engine power output to the output shaft 44 to the reduction gear shaft 38 is disposed below the front end of the engine unit 0.
is rotatably supported via bearings 47 and 47 in a cylindrical portion 46 connecting the gear case 33 and the bearing housing 20a. , a reducing spur gear 49 on the front end of the output shaft 44 meshes with the reducing spur gear 49, and a reducing bevel gear 5o formed on the outer peripheral surface of the other end on the opposite side meshes with the internal teeth 51 on the inner end surface of the reduction gear shaft 38. Due to these meshes, for example, the reduction ratio becomes 1.
A 2:1 secondary speed reduction section 54 is configured, and the rotation of the output shaft 44 is reduced by 1/124 and transmitted to the reduction gear shaft 38. Therefore, in the case of this embodiment, the output sum 44 and the intermediate shaft 45 constitute a power transmission structure, and the absolute reduction ratio therebetween is 60:1.

Note that a one-sided clutch 52 is interposed between the output shaft 44 and the reduction spur gear 49, which allows power to be transmitted only from the output @44 side to the four reduction spur gears.

By the way, a hollow cylindrical starting rotating shaft 55a is supported in parallel with the output shaft 44 at the upper end of the bearing housing 20a. A slider 56 is fitted into the front end opening of the starting rotation shaft 55a, and a driven shaft 55b is coaxially fitted into the rear end opening of the starting rotation shaft 55a. A boss portion 57a of a small starting gear 57 is rotatably attached to the outer peripheral surface of the slider 56. The boss portion 57a + of the starting small gear 57 is straddled over the front end of the starting rotating shaft 55a, and its inner circumferential surface is spline-engaged with the outer circumferential surface of the starting rotating shaft 55a. It is linked to a starting lever (not shown) via a wire 59 inserted through the rotating shaft 55a.
When the starting lever is slid backward by operating the starting lever, the small starting gear 51 resists the biasing force of the return spring 70 and meshes with the large starting gear Go, which is integrated with the reducing spur gear 49. ing. Moreover, when the slider 56 is slid, this slider 5G and the driven shaft 5
5b is compressed, and this compressive force causes the driven shaft 55b to integrally slide rearward. A boss portion 62a of a small starting gear 62 is rotatably mounted on the outer peripheral surface of the subordinate eight shaft 55b, and an interlocking shaft 63 is coaxially mounted on the boss portion 62a. The front end of 63 enters into the step end opening of the starting rotary shaft 55a and is spline-engaged with the inner circumferential surface thereof. and,
A one-sided clutch 66 that allows power transmission only from the interlocking shaft 63 side is interposed between the boss portion 62a of the starting small gear 62 and the interlocking shaft 63. Therefore, the driven shaft 5
5b is slid rearward, the starting small gear 62 resists the urging force of the return spring 64 and meshes with the starting large gear 65 mounted between the flywheel magneto 17 and the clutch 19. By means of the starting small gears 57 and 62, the starting large gears Go and 65, the starting rotating shaft 55a1 interlock @ 63, and the one-sided clutch 66, a detour route 67 that bypasses the -th gear reduction section 53 is created. has been completed.

Note that the reference number 68 in FIG. 3 indicates a fuel tank, and the reference numeral 69 indicates an electrical equipment case containing a battery and various other electrical parts (not shown).

Next, the effect of the above combination will be explained.

When riding the pedals 36.36 as a normal bicycle, the rotational driving force transmitted to the pedal crankshaft 34 through the pedal cranks 37.37 is transferred to the one-way clutch 3.
9 to the reduction gear shaft 38, and from there to the drive sprocket 40. It is transmitted to the rear wheel 11 through the chain 43 and free sprocket 42. Note that at this time, the reduction gear lN138 is interlocked with the output shaft 44 via the intermediate shaft 45, but when rotational force is input from the intermediate shaft 45 side, the reduction spur gear is rotated by the action of the one-way clutch 52. 49 idles on the output shaft 44 and no power is transmitted to the output shaft 44, so that the -th gear reduction section 53 is not dragged and rotated, and the pedal can be driven easily.

In addition, when traveling by engine power, the output shaft 44
The engine power extracted after being decelerated to 1.75 is
The signal is transmitted to the reducing spur gear 49 via the one-way clutch 52, and is further transmitted to the reducing spur gear 49 by the secondary reduction unit 54.
12 and is transmitted to the reduction gear shaft 38, and thereafter transmitted to the rear wheel 11 in the same manner as described above.

Note that in both of these running conditions, the reduction spur gear 49
(18 driving large gear 60 and starting small gear 57)
Further, since the large starting gear 65 and the small starting gear 62 do not mesh unless the starting lever is operated, no power is transmitted to the detour route 67.

On the other hand, to start the engine, the reduction spur gear 49 is forced to rotate by depressing the pedal crank 37° 37, as in the case of traveling as a bicycle. Then, in this state, operate the start lever and move slider 5.
6 slides backward, the starting small gear 57 meshes with the starting large gear 60 and the starting rotating shaft 55a rotates, and at the same time, the driven shaft 55b slides backward under the compressive force of the coil spring 61. The starting small gear 62 on the outer peripheral surface meshes with the starting human gear 65. Therefore, the rotational force taken out to the starting large gear 60 through the reducing spur gear 49 is transferred from the starting small gear 57 to the starting rotating shaft 55.
a, interlocking shaft 63. One-way clutch 66, starting small gear 6
2 and v) It is directly transmitted to the crankshaft 1G of the engine 14 via the user tooth width 65.

Note that when the engine 14 starts, the starting pinion 62 rotates at a higher speed than the interlocking shaft 63, but there is a gap between the starting pinion 62 and the interlocking shaft 63 from the interlocking shaft 63 side. Since a one-way clutch 66 that only allows power transmission is interposed, when rotational force is input from the starting pinion 62 side, the starting pinion 62 idles on the interlocking shaft 63 and the interlocking stops. No power is transmitted to the shaft 63, which is safe.

According to such an embodiment of the present invention, at the time of starting, the rotational force transmitted from the pedal crankshaft 34 side to the output end of the output shaft 44 is transferred to the detour path 6 that bypasses the -th order reduction section 53.
7 directly to the crankshaft 16, the -th order reduction unit 53 is not used and rotates, and as a result, when starting, the speed increasing ratio is 60 when viewed from the pedal crankshaft 34 side. :1 to 12:1, so
Therefore, the pedal can be driven more easily.

Moreover, according to the above configuration, the power transmission path from the output end of the output shaft 44 to the reduction gear shaft 38 is the same as when driving, so the number of shafts and gears does not increase significantly. The housing 20a and the area around the casing 20 can be made more compact, and the number of parts can be reduced due to the sharing of the power transmission path, so the structure can be simplified accordingly, contributing to cost reduction. do.

In the above-described embodiment, the -order reduction section is bypassed, but depending on the case, the secondary reduction section may be bypassed, and the configurations of the -order and secondary reduction section may, of course, be changed. The configuration of the detour route is also not limited to the above embodiment, and can be implemented with various modifications.

〔Effect of the invention〕

According to the present invention described in detail above, at the time of starting, the rotational force on the drive shaft side is transmitted to the crankshaft side of the engine through a detour route that bypasses a part of the reduction section.
All the reduction parts inside are not dragged and rotated, and as a result, when starting η'-3, the lid speed ratio decreases when viewed from the drive shaft side, so the pedal drive must be reduced accordingly. can be done.

Moreover, since part of the power transmission path is the same as the 11th gear, there is no need to significantly increase the number of axes or gears.

Therefore, the entire device can be made more compact, and the number of parts can be reduced, so the structure can be simplified accordingly, which has the advantage of contributing to cost reduction.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is an overall sectional view, FIG. 2 is a sectional view taken along line II-IF in FIG. 1, FIG. 3 is a side view of a moped bicycle, and FIG. FIG. 4 is a view in the direction of the arrows ``■'' in FIG. 3. 8... Saddle, 14... Engine, 1G... Crankshaft, 44, 45... Power transmission mechanism (output shaft, intermediate shaft), 33... Gear case, 37... Pedal crank, 38... Drive shaft, 53, 54... Reduction section (-large reduction section, secondary reduction section), 67... Detour route.

Claims (1)

[Claims] A gear case located below the saddle pivotally supports a drive shaft that is artificially rotationally driven by a pedal crank, and this drive shaft and the engine crankshaft are connected to the rotation of the crankshaft. When starting the engine, depressing the pedal crank causes the engine to move from the drive shaft side to the crankshaft side. A motorized bicycle that transmits power and starts the engine with this pedal crank, and when power is transmitted from the drive shaft side to the crankshaft side, the rotational driving force of this drive shaft is transferred to the reduction section. A power transmission device for a motorized bicycle, characterized in that a detour route is provided for transmitting power to a crankshaft side by detouring a part of the power.