JPH0468164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power transmission device for a small vehicle.

[Conventional technology and its problems]

2. Description of the Related Art In small motorcycles or tricycles such as scooters, a power unit is often used as a power source, which is an integral structure of an engine and a power transmission system that transmits the driving force of the engine to a drive shaft. The above power unit usually has a built-in centrifugal clutch, and the engine's driving force is transmitted to the drive wheels only when the engine speed is higher than the idling speed, and when the engine is idling or stopped. Sometimes, the centrifugal clutch is disengaged, and power is not transmitted between the engine and the drive wheels.

Therefore, in a small vehicle equipped with the above conventional power unit, it is not possible to lock the driving wheels (so-called parking lock) by applying engine braking when the vehicle is stopped.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a power transmission device for a small vehicle that can lock the drive wheels by engine braking when the vehicle is stopped, has a simple structure, and can be manufactured at low cost. shall be.

[Means for solving problems]

In order to achieve this object, the present invention provides a latch mechanism between the clutch outer and the clutch inner that constitute the centrifugal clutch, and when the clutch outer is about to rotate relative to the clutch inner in the forward rotation direction, the clutch outer is moved toward the clutch inner. The structure is such that it engages with the

[Effect]

For example, when the vehicle is parked on a downhill slope, the drive wheel receives a force that tries to rotate it in the normal rotation direction due to gravity, but the drive wheel is in a relationship where the clutch outer engages with the clutch inner via a ratchet mechanism. Above, it is connected to the engine and locked.
Rotation is regulated.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a power unit for an automatic tricycle to which the present invention is applied, and in the figure, reference numeral 1
is the crankshaft. A drive pulley 2 is provided on the crankshaft 1 so as to rotate integrally with the crankshaft 1. Reference numeral 3 denotes an output shaft arranged parallel to the crankshaft 1, and a driven pulley 4 is rotatably arranged on the output shaft 3. An endless V-belt 5 is wound between the driving pulley 2 and the driven pulley 4.

The driven pulley 4 is composed of a fixed pulley half 6 and a movable pulley half 7. The fixed pulley half 6 is fixed to a sleeve 8 rotatably attached to the output shaft 3, and the other drive pulley The half body 7 is fixed to a cylindrical slider 9 that is attached to the outer circumference of the sleeve 8 so as to be non-rotatable and slidable in the axial direction. A spring 11 is disposed between the slider 9 and a drive plate 10 spline-fitted to the outer periphery of the sleeve 8, which causes the slider 9 and the movable pulley half 7 to move toward the right in the figure. energized.

A centrifugal clutch 12 is interposed between the output shaft 3 and the driven pulley 4. Centrifugal clutch 12
is rotatably attached to the drive plate 10 at one end and a spring (not shown) at the other end.
a clutch inner body 13 consisting of a clutch inner body 13a which is biased inward in the radial direction by a clutch inner body 13; a bottom cylindrical clutch outer 14;
It is attached to the outer periphery of the other end of the clutch inner body 13a, and when the other end of the clutch inner body 13a moves outward at a rotational speed exceeding the idling state, it comes into pressure contact with the inner periphery of the clutch outer 14, and the clutch inner 13 is It consists of a friction pad 15 that transmits rotation to the clutch outer 14. Note that 16 and 17 each indicate a nut.

The above configuration is substantially the same as the conventional configuration. The characteristic part of this embodiment is that the clutch inner 13
A latch mechanism 18 is interposed between the clutch outer 14 and the clutch outer 14, so that when the clutch outer 14 attempts to rotate relative to the clutch inner 13 in the normal rotation direction, the clutch outer 14 and the clutch inner 13 are becomes engaged.

That is, a ratchet 19 that is integrally provided with the output shaft 3 is attached to the inside of the clutch outer 14 (on the right side in the figure), and a ratchet pawl 20 is attached to the drive plate 10. A spring 21 is installed so that the pawl 20a engages with the ratchet 19.
(See Figure 2). Here, the strength of the spring 21 is such that when the engine does not reach an idling state, the pawl portion 20a can be moved radially inward and engaged with the ratchet 19, but when the engine speed reaches above idling, As shown by the two-dot chain line in FIG. 2, the strength is set to allow the radially outward movement of the pawl 20a to which centrifugal force is applied, and to release the engagement between the pawl 20a and the ratchet 19. has been done.

In addition, to provide a supplementary explanation of the power transmission system below the output shaft 3, when the forward/backward switching mechanism 31 sets the forward drive side, that is, when the slider 32 is moved to the left in the figure and meshes with the intermediate gear 33, The rotation of the output shaft 3 is caused by the intermediate gear 33 meshing with the gear formed integrally with the output shaft 3, the slider 32, the shaft 34, the gear 35 meshing with the gear integrally forming the shaft 34, etc. Drive shaft 3 through
6. On the other hand, the forward/backward switching mechanism 31
When the slider 32 is moved to the right side in the figure and meshed with the intermediate gear 37, the rotation of the output shaft 3 is
When the back gear 38 meshing with the gear integrally formed with the slider 32 moves to the right in the figure, it is connected to the back gear 38 and power is transmitted through the intermediate gear 37, shaft 34, gear 35, etc. and is transmitted to the drive shaft 36.

Next, the operation of the power transmission device will be explained.

When parking a tricycle equipped with the power unit described above on a downhill slope, the slider 32 is shifted to the forward side (to the left in the figure) by the forward/reverse switching mechanism 31. At this time, the driving wheel receives a force that tries to rotate it in the forward direction due to gravity, but the driving wheel is connected to the output shaft 3 via the gear 35, the shaft 34, the intermediate gear 33, etc. Furthermore, it is connected to the engine side via the clutch outer 14, the latch mechanism 18, the clutch inner 13, the driven pulley 4, the V-belt 5, and the drive pulley 3, and is locked by the friction of the engine, so that its rotation is regulated.

On the other hand, when parking the tricycle on an uphill slope, the forward/backward switching mechanism 31 shifts the slider 32 to the backward side (to the right in the figure) and connects the drive wheel to the output shaft 3 via the back gear 38 or the like. The rotation of the clutch can be regulated by connecting the clutch to the engine via the clutch outer 14, the latch mechanism 18, the clutch inner 13, the driven pulley 4, etc., and locking it by the friction of the engine.

Further, according to the above power transmission device, since the clutch inner 13 and the clutch outer 14 are engaged with each other by the ratchet mechanism 18 when the rotation speed is below a predetermined number, it is possible to push start the engine. That is, when the slider 32 is shifted to the forward side and the vehicle is pushed forward, the rotation of the drive wheels is caused by the drive shaft 36, the gear 35, and the shaft 3.
4 is transmitted to the output shaft 3 via the intermediate gear 33, and the rotational force is further transmitted to the crankshaft 1 via the clutch outer 14, the ratchet mechanism 18, the clutch inner 13, the driven pulley 4, the V-belt 5, and the drive pulley 2. Rotate the engine.

On the other hand, when the engine starts and enters a normal running state, the engine output is transmitted to the clutch inner 13 via the drive pulley 2, V-belt 5, etc.
Further, the power is transmitted from the clutch outer 14 to the power transmission system at a later stage to rotate the drive wheels. At this time, the ratchet mechanism 18 engages the ratchet pawl 20.
The centrifugal force acts to move the pawl portion 20a outward, so that the pawl portion 20a is in a disengaged state.

Further, when the engine is in an idling state, the ratchet mechanism 18 and the centrifugal clutch 1
2 are in a disengaged state, and only the engine and the power transmission system from there to the clutch inner 13 are rotationally driven, and friction loss to the engine is reduced.

Note that the present invention is not limited to the above-mentioned embodiments, and can be applied to a power transmission device not equipped with a reverse device or a power transmission device for an automobile.

〔Effect of the invention〕

As explained above, according to the present invention, since the ratchet mechanism is provided between the clutch outer and the clutch inner, the driving wheels can be locked by engine braking when the vehicle is stopped, and as described above, the clutch outer and the clutch inner can be locked. Since it has an extremely simple structure in which a ratchet mechanism is provided between the clutch inner and the clutch inner, it can be manufactured at low cost and has excellent effects such as being able to be pressed to start.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a power unit to which the present invention is applied, FIG. 2 is a side view illustrating a ratchet mechanism, and FIG. 3 is an enlarged sectional view of a part of the power unit. 1... Crankshaft, 2... Drive pulley, 3...
Output shaft, 4...Driven pulley, 5...V belt, 1
0... Drive plate, 12... Centrifugal clutch, 13... Clutch inner, 13a... Clutch inner body, 14... Clutch outer, 18...
...Ratchet mechanism, 19...Ratchet, 20...
...Ratchet pawl, 20a...Claw portion, 21...Spring, 31...Forward/backward switching mechanism.

Claims (1)

[Claims] 1 A drive pulley driven by an engine, a driven pulley connected to the drive pulley via an endless belt, an output shaft that rotatably supports the driven pulley, and an interposed device between the driven pulley and the output shaft. The centrifugal clutch includes a clutch inner provided to rotate integrally with the driven pulley, and a clutch inner disposed at an interval on the outer circumferential side of the clutch inner and integral with the output shaft. A clutch outer is provided so as to rotate, and a clutch inner is provided on the outer periphery of the clutch inner, and when the clutch inner reaches a predetermined number of rotations and moves radially outward, the clutch inner presses against the inner periphery of the clutch outer to transmit rotation to the clutch outer. In the power transmission device for a small vehicle, the clutch outer is connected to the clutch inner only when the clutch outer is about to rotate relative to the clutch inner in the forward direction. 1. A power transmission device for a small vehicle, characterized in that it is provided with a ratchet mechanism for aligning.