JPH037617Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mounting structure for a centrifugal clutch suitable for use in small engine units particularly installed in motorcycles, tricycles, etc.

Although it is desirable to keep the total width of the engine unit as small as possible due to space layout, in the case of an engine unit with a built-in centrifugal clutch,
There were issues such as the space to accommodate the clutch spring coil diameter and the thickness of the clutch inner and collar in the direction of the crankshaft to prevent the clutch inner from falling over, so it was necessary to reduce the overall width of the engine unit while maintaining the performance of the centrifugal clutch. It's difficult. Therefore, it is also possible to use the side surface of the flywheel as a clutch inner and attach the clutch weight directly to the side surface of the flywheel. However, the shoe of the clutch weight is generally processed with the clutch weight attached to the clutch inner, and machining the shoe with the clutch weight attached to the flywheel inevitably results in high costs.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a mounting structure for a centrifugal clutch that can reduce the overall width of an engine unit while maintaining the performance of the centrifugal clutch. be.

In order to achieve the above object, the present invention provides a flywheel and a clutch inner of a centrifugal clutch adjacent to each other on a crankshaft, an opening is formed in the side surface of the flywheel, and a part of the clutch inner is engaged with this opening. The present invention is also characterized in that a mounting portion between the opening arm and the clutch inner, which is provided with a shoe that expands due to centrifugal force and connects to the clutch outer, is located within the opening.

Hereinafter, a case will be described in which a preferred embodiment of the present invention is applied to an engine unit of a motorized bicycle.

Figure 1 shows a left side view of the main parts of a motorized bicycle.
Figure 2 is a cross-sectional plan view of the main parts of the engine unit.
FIG. 3 shows a left side cross-sectional view of the same essential parts.

The body frame 2 of the motorized bicycle 1 includes a seat post 5 with a saddle 3 attached to its upper end and a pipe material 4 welded to its lower end, and the rear end of an upper down tube 6 extending rearward from the head tube is connected to the seat post. The rear ends of the lower down tubes 7 are connected to the pipe materials 4 at the intermediate portions of the pipes 5, respectively.

A bifurcated rear fork 8 extends rearward from the pipe material 4, and a rear wheel 9 is supported at the rear end of the rear fork 8.

A drive shaft 11 is inserted into the pipe material 4 in the left and right direction, and pedals 12 are provided at both left and right ends of the drive shaft 11, respectively.
A drive sprocket 13 is installed on the drive shaft 11 near the pedal 12 on the right side, and a chain 15 is hung over the drive sprocket 13 and the driven sprocket 14 provided on the rear wheel 9 side.
The motorized bicycle 1 can be freely moved forward by the rotation of the motorized bicycle 1.

A fuel tank 21 is disposed in front of the lower part of the seat post 5 between the upper down tube 6 and the lower down tube 7, and an oil tank 23 is disposed between the lower part of the seat post 5 and the rear fender 22.
An electrical component box 24 is arranged below the rear of the lower down tube 7.

The engine unit 31 is provided below the rear end of the lower down tube 7 and the front part of the rear fork 8, and in this embodiment is a two-cycle engine and includes a drive roller 32 that can be freely pressed against the rear tire 9a.

As shown in FIGS. 2 and 3, the engine unit 31 includes a cylinder head 34 fitted with a plug 33, a cylinder block 36 fitted with a piston 35, and a crankshaft 38 connected to the piston 35 via a connecting rod 37. The crankshaft 38 is supported by left and right crankcases 41 and 42, and a crankcase cover 43 is attached to the left crankcase 41 to define a mission chamber 44. A reduction mechanism 45, a centrifugal clutch 46, and an ACG 47 are installed inside.

The drive roller 32 is rotatably supported by the rear part of the left crankcase 41 and the rear part of the crankcase cover 43, and is attached to the right end of the drive shaft 51 parallel to the crankshaft 38 so as to rotate together with the drive shaft 51.

An engine hanger 52 is provided to protrude upward from the front part of the crankcase cover 43, and the engine hanger 52 and the pipe material 4 are pivotally connected via a support shaft 53.

A cam 55 is disposed below the front of the rear fork 8 and can be rotated via a wire 54 by operating an operating section provided on the handle, and a portion deviated from the center of the cam 55 is connected to the rear end of the crankcase cover 43. is connected via the rod 56, and the cam 55 is rotated by operating the operating section, and the support shaft 53 is connected via the rod 56.
The rear part of the engine unit 31 is swung up and down using the fulcrum as a fulcrum, and the drive roller 32 is freely pressed against the rear tire 9a.

An oil pump 61 is attached to the rear upper surface of the crankcase cover 43, and a drive gear 62 of the oil pump 61 and an oil pump drive gear 63 of the drive shaft 51 are engaged with each other, so that a portion of the drive shaft 51 closer to the left crankcase 41 An input gear 64 is attached to the input gear 64 so as to rotate integrally with the drive shaft 51.

A support plate 71 is provided on a portion of the crankshaft 38 exposed from the left crankcase 41 to the crankcase cover 43 side so as to rotate integrally with the crankshaft 38.
and fix the crankshaft 38 on the left side of the support plate 71.
A distance collar 72 is fitted into the portion so as to rotate integrally with the crankshaft 38.

Approximately on the right half of the distance collar 72, a ratchet wheel 7 is rotatably mounted via a needle bearing 73.
4 is installed, and the sun gear 7 is rotatably mounted on the left half of the road.
Fit 5.

At both ends of the support plate 71, claws 76 which can be freely engaged and disengaged from the ratchet wheel 74 are provided and biased toward the ratchet wheel 74, and the ratchet wheel 74 is rotated counterclockwise as shown in FIG. The ratchet wheel 74 and pawl 76 are formed so as to engage with each other when moved.

A gear 81 that meshes with the input gear 64 is fitted to the left end of the ratchet wheel 74 so as to rotate integrally with the ratchet wheel 74, and a planetary gear 83 is rotatably connected to the left side of the gear 81 via a pin 82. Install.

The planetary gear 83 is connected to the left crankcase 4.
Ring gear 84 installed non-rotatably at joint part 1
The sun gear 75, the gear 81, the planetary gear 83, and the ring gear 84 constitute a speed reduction mechanism 45.

A cylindrical portion 9 of a required diameter is provided at the left end of the sun gear 75.
1a to the sun gear 75.
Install it so that it rotates integrally with the

A collar 92 is fitted to the crankshaft 38 portion on the left side of the distance collar 72.
A clutch inner 93 and a flywheel 94 are fitted to the left side of the flywheel 2, and the clutch inner 93 is connected to the base of the side surface 94a of the flywheel 94 via a nut 95 and a holding member 96 from the left side of the flywheel.
The pin 97 implanted in the crankshaft 38 is fitted into the keyway of the flywheel 94, and the flywheel 94 is secured to the crankshaft 38.
A bearing 9 is formed to rotate integrally with the crankshaft 38, and the left end of the crankshaft 38 is assembled into the crankcase cover 43.
Supported by 8.

A cylindrical portion 94b extending leftward is formed on the outer periphery of the flywheel 94, a rotor 101 is disposed on the inner peripheral surface of the cylindrical portion 94b, and the crankcase cover 4
The stator 102 and the rotor 101 fixedly attached to
and form ACG47.

The side surface 94a of the flywheel 94 is provided with openings 103, 103 extending a required length in the circumferential direction around the crankshaft 38.

As shown in a plan view in FIG. 4a and in a cross-sectional view in FIG. base 93a of
and the flywheel 9 from both ends of the base 93a.
It consists of mounting steps 114, 114 that are bent into a step shape toward the 4 side and slightly intrude into the opening 103, projecting pieces 115, 115 protruding from the base 93a toward the flywheel 94 side, and the mounting steps. Part 11
Projecting pieces 116, 116 protruding toward the flywheel 94 from 4, 114 are engaged with the peripheries of the openings 103, 103 of the flywheel 94, respectively, so that the clutch inner 93 is formed to rotate together with the flywheel 94.

A mounting hole 117 is formed in the mounting step 114, and a pair of opening arms 121, 121 are pivotally mounted via a support shaft 118 inserted through the mounting hole 117.

The opening arms 121, 121, as shown in a plan view in FIG. 5a and in a sectional view in FIG.
Shoe 12 that can be freely joined to the cylindrical portion 91a of 1
2, and a coil spring 123 is stretched between the base of one opening arm 121 and the middle part of the other opening arm 121, so that the normally opening arm 12
1, 121 in the direction of diameter reduction. When the clutch inner 93 reaches a predetermined rotational speed, the opening arms 121, 121 expand outward in diameter, and the shoes 122, 122 are formed to be joined to the cylindrical portion 91a, and a portion of the spring 123 is shown in FIG. into the opening 103 as shown in FIG.

the clutch inner 93, the opening arm 121,
A centrifugal clutch 46 is composed of a coil spring 123, a clutch outer 91, etc., and 131 in the drawing is a bistar.

Next, the action and effect will be explained.

When the motorized bicycle 1 is moved forward by rotating the pedals 12, the cam 55 is rotated by operating the operating section of the handlebar, and the rear part of the engine unit 31 is swung downward by its own weight, and the driving roller 3 is rotated.
2 and the rear tire 9a are separated. Due to the separation between the drive roller 32 and the rear tire 9a, the connection between the engine unit 31 and the rear wheel 9 is cut off, and the motorized bicycle 1 is moved forward by rotation of the pedals 12, similar to a bicycle.

When moving the motorized bicycle 1 forward using engine power, the motorized bicycle 1 is first moved forward at a predetermined speed by rotating the pedals 12, and when the predetermined speed is reached, the cam 55 is rotated by operating the operating section of the handlebar. Then, the rear part of the engine unit 31 is swung upward via the rod 56, and the drive roller 32 is pressed against the rear tire 9a.

The drive shaft 51 rotates due to the pressure of the drive roller 32 against the rear tire 9a, and the input gear 64 and oil pump drive gear 63 rotate. The drive gear 62 is rotated by the rotation of the oil pump drive gear 63,
The oil pump 61 is driven.

The rotation of the input gear 64 causes the gear 81 to rotate counterclockwise in FIG. 3, causing the ratchet wheel 74 to rotate counterclockwise. The engine 39 is rotated counterclockwise and started. In this case gear 81
Due to the rotation, the planetary gear 83 rotates and revolves around its axis, causing the sun gear 75 to rotate counterclockwise.
The clutch outer 91 is rotated integrally with the sun gear 75, but when the rotational speed of the crankshaft 38 is below a predetermined rotation speed, the opening arms 121, 121 are in a reduced diameter state and the connection between the clutch inner 93 and the clutch outer 91 is cut off. And the clutch outer 91 simply rotates idly.

When the engine 39 starts and the crankshaft 38 reaches a predetermined rotational speed or higher, the opening arms 121, 121 expand in diameter, the shoe 122 joins the cylindrical portion 91a, the clutch outer 91 rotates together with the clutch inner 93, and the clutch outer 91 and sun gear rotate. 75 rotates counterclockwise integrally with the crankshaft 38.

The rotation of the sun gear 75 causes the planetary gear 83 to
rotates in the clockwise direction and revolves in the counterclockwise direction, rotates the gear 81, and rotates the planetary gear 83.
The engine power decelerated by the revolution of the gear 8
1. The power is transmitted to the rear wheel 9 via the input gear 64 and the drive roller 32, and the motorized bicycle 1 is moved forward by the engine power. In this case, the ratchet wheel 7 is integrated with the gear 81.
4 is rotating counterclockwise, but the rotational speed of the pawl 76 and the support plate 71 is the rotational speed of the crankshaft 38, which is higher than the rotational speed of the pawl wheel 74, so the pawl 76 rotates counterclockwise. The ratchet wheel 7 without engagement.
4. Rotate while sliding on top. Note that when the rotational speed of the ratchet wheel 74 due to the rotation of the rear wheel 9 becomes greater than the rotational speed of the crankshaft 38, that is, during deceleration, the ratchet wheel 74 engages with the pawl 76, and engine braking is applied to the rear wheel 9. .

In the above, the mounting step part 1 of the clutch inner 93
14. Since the support shaft 118, coil spring 123, etc. are located within the opening 103 of the flywheel 94, and the space in the thickness direction of the flywheel side surface 94a is effectively utilized, the horizontal width of the engine unit 31 is reduced accordingly. be able to.

Furthermore, a portion of the clutch inner 93 is provided to protrude toward the flywheel 94 side to form protrusions 115 and 116, and these protrusions are engaged with the periphery of the opening 103, so that the clutch inner 93 and the flywheel 94 can be easily connected. Can be integrated.

From this, the base 93a of the clutch inner 93
Tighten together with the base of the flywheel side surface 94a,
Since the base of the flywheel side surface 94a is used as a mounting surface for the clutch inner 93, there is no risk of the clutch inner 93 falling with respect to the crankshaft 38, and therefore the thickness of the clutch inner 93 can be made as small as possible, and the centrifugal clutch 46 and engine unit can be easily mounted. The horizontal width of 31 can be further reduced.

When applied to a conventional engine unit, it is only necessary to form an opening 103 on the flywheel side surface 94a and a mounting step 114 on the clutch inner 93, so that the present invention can be easily applied to a conventional engine unit.

As is clear from the above explanation, according to the present invention,
It exhibits many excellent effects, such as being able to reduce the overall width of the engine unit while maintaining the performance of the centrifugal clutch, and having a simple structure that can be easily applied to conventional engines.

[Brief explanation of the drawing]

Figure 1 is a left side view of the main parts of the motorized bicycle, Figure 2 is a sectional plan view of the main parts of the engine unit, and Figure 3 is a sectional plan view of the main parts of the engine unit.
The figure is a sectional left side view of the same essential part, FIG.
FIG. 5a is a plan view of the centrifugal clutch, and FIG. 5b is a cross-sectional view taken along the line bb--b at a. In the drawing, 9a is a rear tire, 31 is an engine unit, 32 is a drive roller, 38 is a crankshaft, 47 is an ACG, 91 is a clutch outer, 93
is clutch inner, 94 is flywheel, 10
3 is an opening, 121 is an opening arm, and 123 is a coil spring.

Claims (1)

[Scope of utility model registration request] The flywheel and the clutch inner of the centrifugal clutch are provided adjacent to each other on the crankshaft, and an opening is formed in the side surface of the flywheel, and a portion of the clutch inner is engaged with this opening, and is expanded by centrifugal force to the clutch outer. 1. A mounting structure for a centrifugal clutch, characterized in that a mounting portion between an opening arm and a clutch inner including a shoe to be joined is located within the opening.