JPS6147348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power transmission device for an internal combustion engine suitable for vehicles such as light motorcycles.

More specifically, in a power transmission device in which a planetary gear type automatic transmission consisting of a combination of a planetary gear mechanism and a centrifugal force expansion clutch for speed change provided in parallel with the mechanism is disposed on the drive shaft of an internal combustion engine, The centrifugal force expansion type clutch for speed change is provided in the internal space formed by the plurality of inner members of the centrifugal force expansion type clutch for starting that connects and disconnects the drive shaft and the planetary gear type automatic transmission, and one The present invention relates to a power transmission device for an internal combustion engine, in which two clutches are accommodated in a clutch space, thereby making effective use of dead space and reducing the axial width of the device.

Various mechanisms and structures are known as power transmission devices for vehicles, but an automatic transmission mechanism that can automatically shift from first to second or higher speeds as the rotational speed of the internal combustion engine increases. In a power transmission device equipped with a power transmission device, the number of parts increases due to the need for clutches for starting and gear shifting, and the structure becomes complicated as a result.As a result, the device inevitably becomes larger. It is. Among the various types of vehicles that require a power transmission device equipped with an automatic transmission mechanism, there are light motorcycles that are lightweight and compact, and the automatic transmission mechanism makes them easy to drive even by those who are not proficient in driving. This is useful for motorcycles of this type that are required to be able to

However, since the body of a light motorcycle is made as compact as possible, there is not a lot of space for assembling various necessary parts and equipment, and the overall device tends to be large. When manufacturing a power transmission device, it is required to miniaturize it so that it can be sufficiently assembled into a limited space, and this challenge is imposed on the design.

The present inventors have made the present invention in view of the above points, and have made the present invention so that it is suitable for application mainly to light motorcycles.

An object of the present invention is to provide a planetary gear type automatic transmission for an internal combustion engine, which is a combination of a planetary gear mechanism consisting of a ring gear, a planet gear, and a sun gear, and a centrifugal force expansion clutch for speed change provided in parallel with the planetary gear mechanism. In the power transmission device disposed on the drive shaft, a centrifugal force expansion type clutch for starting is provided to connect and disconnect the drive shaft and the planetary gear type automatic transmission, and a plurality of centrifugal force expansion type clutches for starting are provided. A power transmission device for an internal combustion engine is provided, in which the centrifugal clutch for speed change is provided in an internal space formed by an inner member of the present invention.

Therefore, the object of the present invention is that although two centrifugal clutches are used, one for starting and one for shifting, the centrifugal clutch for shifting is housed in a dead space inside the centrifugal clutch for starting, so that the clutch space is reduced. To provide a power transmission device for an internal combustion engine, which requires only one clutch, makes effective use of dead space, and is designed to reduce the size of the device, particularly the width in the axial direction.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an overall sectional view of a power transmission device according to the present invention, and FIG. 5 shows a schematic structure thereof in a line diagram.

This power transmission device is used in lightweight and compact light motorcycles. 10 is an internal combustion engine consisting of a piston 10a, etc., and the internal combustion engine 10
A crankshaft, ie, a drive shaft 11, is supported by a bearing 12 at its base, and its front end extends into a case 13. Inside the case 13, a starter shaft 14 is rotatably supported by a shaft support 13a, and the drive shaft 11
The spiral spring 1 is placed on the outer periphery of the end.
5 has one end on the case 13 side, and the other end on the starter shaft 1
It is fixed and provided on the 4th side. The starter shaft 14 has a sprocket portion 14a on which a chain 16 is installed, and the chain 16 is connected to a foot pedal provided outside the vehicle body, and when the pedal is stepped on, the chain 16, the sprocket portion 14a, and the starter shaft 14 are rotated. The spring 15 is wound up and elastic force for starting the internal combustion engine is stored. One end of the starter shaft 14 is formed to have a large diameter, and a ratchet 14b is formed on the outer peripheral surface of the end. A pawl body 19 pivotally supported by a pin 18 on a drive plate 17, which will be described later and is integrated with the drive shaft 11, is attached to this ratchet 14.
When the starter shaft 14 is rotated by the release of the elastic force of the spiral spring 15, the rotational force is transmitted to the drive plate 17 and the drive shaft 11 by the meshing of the ratchet 14b and the pawl 19, The internal combustion engine 10 starts at the rotation speed of .

After the internal combustion engine 10 is started, the drive shaft 11 and drive plate 17 rotate at high speed, so the claw body 19 rotates outward around the pin 18 due to centrifugal force, and when separated from the ratchet 14b, the drive shaft 11 rotates. guarantee.

In this way, in this embodiment, the internal combustion engine is connected to the spiral spring 1.
Although the present invention is configured to start by artificially releasing the stored power in step 5, it is also possible to adopt a starting method using a kick starter or a starting motor as in a general motorcycle.

The drive plate 17 is fixedly integrated with the tip of the drive shaft 11 by screwing a nut 17a. An inner member 21 of a starting centrifugal clutch 20 is rotatably supported by a pin 23 on the outer periphery of the inner surface of the drive plate 17, which is perpendicular to the drive shaft 11. This arc-shaped inner portion 21 is normally closed inward by a spring 24. The outer member 22 of the starting centrifugal clutch 20 has a drum shape with an open end on the drive plate 17 side and a closed end on the other end. In the above, two inner members 21 are provided within the outer member 22, and the outer surface of the inner member 21 has a shape that conforms to the inner surface shape of the outer member 22. A planetary gear mechanism 28 consisting of a ring gear 25, a planet gear 26, and a sun gear 27 is disposed in close contact with the inner surface of the closed end of this drum-shaped outer member 22, and this mechanism 28
As shown in the figure, three planet gears 26 are provided circumferentially at equal angular intervals. A through hole 27a is formed in the sun gear 27 located at the center, and the drive shaft 11 is inserted through the hole 27a. As shown in FIG. 1, the ring gear 25 located at the outermost periphery is fixed and integrated with the outer member 22 of the starting clutch 20.

Therefore, the planetary gear mechanism 28 serves as the starting clutch 20.
The power of the drive shaft 11 is input to the planetary gear mechanism 28 from the ring gear 25 .

Each of the three planet gears 26 is rotatably supported by a pin 31 on a carrier plate 30, and an output shaft 32 is provided at the center of the carrier plate 30.
Connect and secure the ends. The output shaft 32 is formed into a hollow cylindrical shape and is loosely fitted around the outer periphery of the drive shaft 11.
A sprocket 33, which is a power take-off member, is attached to the other end. A chain 34 connected to a drive wheel of a motorcycle is installed on a sprocket 33.

The end of a cylindrical member 35 loosely fitted to the outer periphery of the output shaft 32 is connected to the sun gear 27, and the cylindrical member 35 is rotatably inserted into the inner diameter hole of the outer member 22 of the starting centrifugal clutch 20 in the same manner as the output shaft 32. The clutch plate 41 of the one-way clutch 40 shown in FIG.
to be fixed. In addition to this clutch plate 41, the one-way clutch 40 includes a pawl body 42 and a ratchet plate 43.
It is rotatably supported at a. As shown in FIG. 1, the ratchet plate 43 is attached to the inner surface of the case 13, which is a stationary member, with bolts 45.
Further, the inner peripheral surface thereof is provided with oblique teeth 43a that are inclined in one direction, and the oblique teeth 43a are covered with an elastic member such as rubber. Clutch plate 4 in direction A in Fig. 4
1 rotation is shown by the chain line between the claw body 42 and the oblique teeth 43a.
Rotation in the direction B, which is opposite to this, is permitted because the pawl body 42 separates from the oblique tooth 43a.

The carrier plate 30 supports the planet gear 26 of the planetary gear mechanism 28 and is connected thereto.
An inner member 51 of a speed change centrifugal clutch 50 is pivotally supported by a pin 53 on the surface opposite to the planetary gear mechanism 28, and this arc-shaped inner member 51 is supported by a spring 5.
4, normally closed inward. The outer member 52 of the speed change centrifugal clutch 50 is attached to the drive plate 17 on the inner diameter side of the inner member 21 of the starting centrifugal clutch 20, that is, the two inner members 2
The drive plate 17 is fixedly integrated within the internal space formed by the drive plate 17, and is attached to the drive plate 17 in a ring shape. As described above, the centrifugal clutch 50 for speed change is provided on the drive shaft 11 so as to face the planetary gear mechanism 28 in the axial direction, and its mounting position is inside the centrifugal clutch 20 for starting, and the internal space of the centrifugal clutch 20 for starting. A centrifugal clutch 50 for speed change is incorporated into. As will become clear from the description below, this transmission clutch 50 is connected to the planetary gear mechanism 28.
Together, they constitute a planetary gear type automatic transmission.

Next, we will discuss the operation.

As described above, after the internal combustion engine 10 is started by releasing the elastic force of the spiral spring 15, when the rotational speed of the internal combustion engine 10 exceeds the idle rotational speed and reaches a predetermined value, the drive shaft 11
The inner member 21 of the starting clutch 20, which is connected via the drive plate 17, expands outward due to centrifugal force and comes into pressure contact with the outer member 22, thereby establishing the connection of the starting clutch 20. The planetary gear mechanism 2 integrated with the outer member 22 through this connection
The ring gear 25 of No. 8 rotates at the same speed and in the same direction as the drive shaft 11. This direction of rotation is defined as direction C as shown in FIG. As the ring gear 25 rotates in the C direction, the planet gear 26 attempts to rotate in the E direction while revolving on the sun gear 27 in the D direction, and as a result, a rotational force is generated in the sun gear 27 in the F direction.
Clutch plate 4 of a one-way clutch 40 connected to the sun gear 27 via the cylindrical member 35
1, a rotational force is generated in the A direction in FIG. 4, which is the same as the F direction (the front and back surfaces are reversed in FIGS. 3 and 4), but the clutch plate 41 cannot rotate in this A direction as described above. That is, the sun gear 27 cannot rotate and is in a stationary state. Therefore, the planet gear 26 rotates in the E direction while revolving in the D direction on the sun gear 27 which remains stationary, the revolution movement is slower than the rotation of the ring gear 25, and the revolution speed of the planet gear 26 is lower than the rotation speed of the ring gear 25. slow.

This revolving motion of the planet gear 26 is taken out to the output shaft 32 via the carrier plate 30, and drives the drive wheels of the motorcycle to the sprocket 33.
is driven in first gear.

When the rotational speed of the internal combustion engine 10 increases, the revolution speed of the planet gear 26 increases accordingly, and the inner member 51 of the centrifugal clutch 50 for speed change, which is rotatably connected to the carrier plate 30 that supports the planet gear 26, increases. When this speed reaches a predetermined value, it is diffused outward by centrifugal force and comes into pressure contact with the outer member 52, and the transmission clutch 50 is connected. The outer member 52 is fixed to the drive plate 17 attached to the drive shaft 11, and the inner member 51 is attached to the carrier plate 30 connected to the output shaft 32. Therefore, when the gear change clutch 50 is connected, the outer member 52 is fixed to the drive plate 17 attached to the drive shaft 11. Since it is directly connected to the output shaft 32, the rotational speed of the output shaft 32 is increased to the same speed as the drive shaft 11, and the speed increase of the output shaft 32 puts the motorcycle in a second speed state.

In this case, the planet gear 26 begins to revolve in the D direction at the same speed as the ring gear 25, which continues to rotate in the C direction, and stops rotating. Therefore, sun gear 2
7 receives a rotational force in the direction G, which is opposite to that at first speed, and since the clutch plate 41 can rotate in this direction, which is the direction B in FIG. 4, the drive shaft 11
When the output shaft 32 and the output shaft 32 are directly connected, the planet gear 26 can revolve without any problem at the same revolution speed as the rotation speed of the ring gear 25. When such a motorcycle is in second gear, the power of the drive shaft 11 is input to the output shaft 32 from both the shift clutch 50 and the planetary gear mechanism 28, and in the power transmission path, the power of the drive shaft 11 is input to the output shaft 32 from both the shift clutch 50 and the planetary gear mechanism 28. 28 are in parallel.

As is clear from the above description, according to the present invention, the centrifugal force expansion type clutch for speed change is provided in the internal space formed by the plurality of inner members of the centrifugal force expansion type clutch for starting. This makes it possible to accommodate two clutches in the same space as the other one, achieving effective use of dead space, and reducing the size of the power transmission system, especially compared to the case where two clutches are arranged axially. It becomes possible to achieve a reduction in the width dimension in the direction, and it becomes possible to solve the design problems mainly required for light motorcycles and meet the demands.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and Fig. 1 is a sectional view showing the entire device, Fig. 2 is a composite view of several parts broken in the axial direction, and Fig. 3 is a view taken from the arrow 3 in Fig. 1. FIG. 4 is a diagram of the one-way clutch seen from the direction of arrow 4 in FIG. 1, and FIG. 5 is a schematic diagram showing the power transmission system in line. In the drawing, 10 is an internal combustion engine, 11 is a drive shaft, and 2
0 is a centrifugal clutch for starting, 28 is a planetary gear mechanism,
32 is an output shaft, and 50 is a centrifugal clutch for speed change.

Claims (1)

[Claims] 1. A planetary gear type automatic transmission consisting of a planetary gear mechanism consisting of a ring gear, a planet gear, and a sun gear, and a centrifugal force expansion clutch for speed change installed in parallel with the planetary gear mechanism is mounted on the drive shaft of an internal combustion engine. In the arranged power transmission device, a plurality of inner members of a starting centrifugal force expansion type clutch that connects and disconnects the drive shaft and the planetary gear type automatic transmission are pivotally connected to a drive plate fixed to an end of the drive shaft. At the same time, a cylindrical outer member having an inner surface shape conforming to the outer surface of the inner member is provided radially outward of the inner member, and the internal space formed by the plurality of inner members of the centrifugal force expansion type clutch for starting is provided. A power transmission device for an internal combustion engine, comprising: an outer member of the centrifugal force expansion type clutch for speed change.