JPS5913139A - Centrifugal multiple disc clutch - Google Patents

Abstract

PURPOSE:To restrain fluctuations in the speed of rotation of a stool by providing a plate spring as a clutch spring for urging the end of either of a clutch plate and a friction plate in the direction of disengaging a clutch and applying substantially tertiary curve-like deflection and load characteristic to the plate spring. CONSTITUTION:In the multiple disc clutch 26, when the rotation of a clutch housing 60 is promoted with the rotation of an engine, a weight 82 is moved outward against a return spring 90 by centrifugal force, which moves a clutch plate 72a to the left with the operation of a cam surface 80. The whole of the clutch plate 72 and a friction plate 74 is moved to the left while a plate spring 84 is deformed, until the clutch 72 and the friction plate 74 are brought into contact with each other to be in the state of clutch connection. In this case, the plate spring 84 is formed in such a manner that load F is substantially constant within a fixed range of deflection having a change characteristic of load F to substantially tertiary curve-like deflection shown by a curve A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a centrifugal multi-plate clutch in which a plurality of clutch plates and friction plates are arranged alternately.

In order to downsize the clutch, there is a multi-disc clutch in which a plurality of clutch plates and friction plates are alternately arranged. Although such a multi-disc clutch can obtain a large torque capacity despite its small outer diameter, the shock at the time of clutch engagement tends to be larger than that of a single-disc clutch.

On the other hand, in a centrifugal clutch, the pressing force of the clutch plate and the friction plate, that is, the friction surface pressure is obtained by the balance between the centrifugal force acting on the weight and the spring force of the clutch spring.

However, when a multi-disc centrifugal clutch is constructed, as mentioned above, multi-disc clutches tend to engage suddenly, resulting in increased friction plate wear and variations in the dimensional accuracy of each component. However, there is a problem in that the stall rotational speed (the rotational speed at which the clutch starts to engage and can transmit a predetermined torque) varies greatly. That is, in the conventional clutch spring, a cylindrical coil spring is used for the clutch spring that presses one end plate of the clutch plate and the friction plate. This coil spring has a linear deflection-load characteristic, so
This is because if the amount of deflection of the spring changes slightly due to wear of the friction plates or variations in component dimensions, the load, that is, the friction surface pressure will change significantly. Therefore, when this clutch is applied to a vehicle such as a motorcycle, a problem arises in that the engine speed at which the vehicle can start (stall speed) varies greatly from vehicle to vehicle.

Furthermore, when a coil spring is used as the clutch spring, there are problems in that the fill spring is deformed by centrifugal force when the clutch rotates, changing the spring characteristics, and the structure becomes complicated, making assembly difficult.

The present invention was developed in view of these circumstances, and it is possible to reduce fluctuations in stall rotational speed due to variations in component dimensions and changes in the amount of wear of friction plates, and also to reduce changes in spring characteristics due to centrifugal force during rotation. The purpose of the present invention is to provide a centrifugal multi-disc clutch that has no problems, has a simple structure, and is easy to assemble.

In order to achieve this object, the present invention locks one of a plurality of clutch plates and friction plates to a clutch housing and the other to a clutch post, and applies centrifugal force of a weight to one end plate of the clutch plates and friction plates. In a centrifugal multi-disc clutch in which one end plate is pressed by a clutch spring and the other end plate is pressed by a clutch spring, the clutch spring is a disc spring, and the disc spring has an approximately zero load change within a predetermined deflection range. It has cubic curve-like deflection and load characteristics. The present invention will be described in detail below based on the illustrated embodiments.

Fig. 1 is a sectional view of a power transmission device for a motorcycle to which the present invention is applied, Fig. 2 is an enlarged view of its clutch, and Fig. 3 is a clutch post and clutch housing of this clutch.
The arrow view and FIG. 4 are diagrams showing the strain/load characteristics of the disc spring.

In FIG. 1, reference numeral 10 denotes an engine unit, which includes an engine 12 and a power transmission device 14 formed integrally with the engine 12. 16 is a piston, and 18 is a crankshaft.

A driven shaft 22 and a rear wheel shaft 24 are held in a case 20 of the power transmission device 14 in parallel with the crankshaft 18 . A dry multi-plate clutch 26 according to the present invention is attached to the shaft end of the driven shaft 22. The rotation of the crankshaft 18 is transmitted to the clutch 26 by a V-belt type continuously variable transmission 28. This clutch 26 is of an automatic centrifugal type as will be described later, and is automatically engaged as the rotational speed of the engine 12 increases.
, the rotation of the crankshaft 18 is transmitted to the driven shaft 22. The rotation of the driven shaft 22 is controlled by the cutter shaft 24.3 through reduction gears 30.32. will be communicated to. This rear wheel shaft 24 has a rear wheel (
(not shown) is attached. .

Next, the V-belt type continuously variable transmission 28 will be explained. This transmission 28 consists of a drive sheave 34 attached to the crankshaft 18, a driven sheave 136 attached to the driven shaft 12, and both sheaves 34 and 36. A belt 38 is provided.

The drive sheave 34 has rigid teeth 34a facing each other.
and a movable disk 34b that slides in the axial direction on the crankshaft 18, both disks 34 a%/J 31
41:38 V-belt clamps are held between b. A spider 40 fixed to the crankshaft 18 is located on the outside of the movable disk 34b, and the radially extending arms of the spider 40 are attached to the crankshaft 18 on the outside of the movable disk 34b.
It engages with a sliding groove 42 formed parallel to the . A ball 4 is disposed between the spider 40 and the outer surface of the movable disk 34b.
4 is held and the ball 44 moves in the radial direction, the ball 44 is guided by the spider 40 and moves toward the movable disk 34b.
is slid toward the fixed disk 34a.

The driven sea 136 has a fixed disk 36a and a movable disk 3.
6b. The fixed disk 36a is fixed to one end of a cylinder 469 rotatably held on the axis of the driven shaft 22. At the other end of this cylinder 46 is a clutch 26 which is located behind the cylinder 46.
A clutch housing 60 is fixed. The movable disk 36b is fixed to a cylindrical sliding member 48 that slides on a cylinder 46, and a coil spring 50 is compressed between the disk 36b and the clutch housing 5.0.

, 5.2 is the length formed in the axial direction of the sliding member 48)
..., groove, 54 A roller that is held in the cylinder 46 and moves within this long groove 52, and this roller 54 is connected to the sliding member 48.
The rotation of the cylinder 46 is transmitted to.

As a result, when the crankshaft 18 rotates at a low speed, the centrifugal force acting on the ball 44 of the driving sheave 34 is small, so the spring force of the spring 50 of the driven sheave 36 overcomes the centrifugal force of the ball 44, and the movable disc 36b approaches the fixed disk 36a. In other words, the reduction ratio becomes larger. Further, as the rotation of the crankshaft 18 increases, the centrifugal force of the ball 44 increases, and when this centrifugal force or the spring force of the spring 50 is overcome, the driving sheave 3
No. 4 movable disk 34b approaches fixed disk 34a. Along with this, the movable disk 36b of the driven sheave 36
pushes the spring 50 and moves away from the fixed disk 36a. Therefore, the reduction ratio becomes smaller.

Next, the dry type multi-disc clutch 26 will be explained. This clutch 2
6 is a clutch housing 60 fixed to the FI cylinder 48
and a clutch boss 62 fixed to the shaft end of the driven shaft 22. The peripheral edge of the clutch boss 62 is connected to the driven shaft 2.
2 and is a cylindrical portion 64 that protrudes toward the clutch housing 60 side substantially parallel to the clutch housing 60 side. On the outer periphery of this cylindrical portion 64, a third
As shown in the figure, a large number of grooves 66 are formed parallel to the driven shaft 22. Further, this cylindrical portion 64 has a bottom of the groove 66,
A plurality of ventilation holes 68 are formed to communicate with the inner surface of the cylindrical portion 64, and the ventilation holes 68 are also open on the side surface of the clutch boss 62.

The clutch housing 60 is provided with a cylindrical portion 70 on its peripheral edge, this cylindrical portion 70 protrudes in parallel with the cylindrical portion 64 of the boss 62, and a plurality of clutch plates 7 are arranged between the two cylindrical portions 70, 62.
2 and a housing portion 76 for the friction plate 74 are formed. These clutch plates 72 and friction plates 74 are arranged alternately so that grooves 78 formed on the inner circumferential surface of the cylindrical portion 70 engage with grooves 66 of the boss 62, respectively. A plurality of cylindrical weights 82 are arranged between a clutch plate 72a serving as one end plate located on the bottom side of the housing portion 76 and a cam surface 80 formed at the bottom of the clutch housing 60. There is. This cam surface 80 moves the weight 82 toward the clutch plate 72 when the weight 82 moves radially outward due to centrifugal force. The inner peripheral edge of a disc spring 84 is in contact with the clutch plate 72b serving as the other end plate on the opening side of the housing part 76, and the outer peripheral edge of the disc spring 84 is fixed to the inner surface of the cylindrical part 70 of the clutch housing 60. It is in contact with the city ring 86. Note that this clutch plate 72b comes into contact with a step 88 formed in the groove 78 (the second
(upper side of the figure), inward movement of the accommodating portion 76 is restricted.

As shown by curve A in FIG. 4, the disk spring 84 has a substantially cubic curve-like change characteristic of load F with respect to strain X, and within a predetermined strain range a, load F is approximately constant. In Fig. 4, the strain/load characteristics of a conventional coil spring are shown by a broken line B. In addition, the cam surface 80 on which the weight 82 rolls has a structure in which the weight 82 rotates when the rotation speed exceeds a predetermined rotation speed.
A stopper 80 that restricts the displacement of this weight 82 by contacting the stopper 80
a is formed. The weight 82 is this stopper, 80a
If the deflection, M, of the disc spring 84 when it hits is set at the end of the deflection range a, and the deflection X(S) at the stall rotational speed is set at the front end, the clutch 26 can be used in the range a. Therefore, the load F1, that is, the friction surface pressure becomes constant.

Further, a return spring 90 is compressed between the clutch plates 72a and 72b at both ends, as shown in the lower side of FIG. The clutch plate 72a has this return spring! -90 guide bin 9
2 is fixed.

A fan 94 is formed in the clutch housing 60 and is located on the inner diameter side of the housing portion 76 and projects toward the clutch boss 62 side. Further, the clutch boss 62 is formed with a large number of air inflow holes 96 located on the inner diameter side of the seventh hole 94.

Next, the operation of this embodiment will be explained. When the engine 12 is running at a low speed, the reduction ratio of the transmission 28 is large and the driven sheave 36 and clutch housing 6o also rotate at a low speed. For this reason, the weight 8
Since the centrifugal force of 2 is small, the clutch plate 72a is returned to the weight 82 side by the return spring 92 (the upper state in FIG. 2). As a result, the clutch plate 72 and the friction plate 74 are separated, and the clutch 2
6 can be cut. In this state, the fan 94 sucks air from the air inflow hole 96 and sends it in the radial direction. In other words, part of this air is between the ventilation holes 68 and the grooves 66,
It flows into the housing part 70 through the space between the housing 6o and the boss 62, cools the clutch plate 72 and the friction plate 74, and then flows out through the groove 78. Further, a part of the air sent by the fan 94 flows out through the ventilation hole 68.

As the rotation of the engine 12 increases, the rotation of the housing 60 also increases. Therefore, the centrifugal force of the weight 82 increases, and when this centrifugal force finally overcomes the spring force of the return spring 90, the clutch plate 72a moves to the left in FIG. Contact pressure increases. When the rotational speed further increases, the entire clutch plate 72 and friction plate 74 become disc springs 84.
while deforming it, it moves toward the disc spring 84 side. Therefore, the spring force of the meter spring 84 becomes the contact pressure between the clutch plate 72 and the friction plate 74. When the rotational speed further increases, the clutch 26 is fully connected, but the heat generated in the clutch plate 72 and friction plate 74 due to slippage after the clutch 26 starts to engage is forcibly dissipated by the air sent to the fan 94. be done.

Therefore, the friction coefficient of the friction plate 74 does not change due to heat, and stable clutch engagement/disconnection characteristics can be obtained, and burnout of the friction plate can be prevented.

When the clutch housing 60 reaches the stall rotational speed, the deflection X of the disc spring 84 becomes x (S), and the clutch 26 starts to be connected. When the engine speed reaches a sufficiently high predetermined speed, the weight 82 hits the stopper 80a (11) on the cam surface 80, and the strain X in the disc spring 84 becomes X1.
It becomes M1. Since this strain xIMl is within the range a where the load F is approximately constant, the friction surface pressure is also constant.

Therefore, even if the engine speed increases thereafter, the clutch 26
The transmitted torque will not increase thereafter. That is, the stopper 80
a has the effect of limiting the maximum value of the transmitted torque. Therefore, it is possible to prevent excessive torque from being applied to the rear wheel drive system due to a sudden start or the like.

Further, even if the friction plate 74 wears out and the deflection X of the disc spring 84 decreases, there is almost no change in the load just before the range a.

Therefore, fluctuations in stall rotational speed are also small. Furthermore, even if there are variations in the dimensions of the parts, if the spring characteristics of the disc spring 84 are sufficiently quality controlled, the structure is simple and easy to assemble because it is simply fixed within the ring 60 with the retaining ring 86.

In this embodiment, the present invention is applied to a dry type clutch, but the present invention also includes an application to a wet type clutch.

(12) As described above, in the present invention, the clutch spring is a disc spring, and the disc spring has a force of approximately 3.5 cm, in which the change in load becomes approximately zero within a predetermined range a.
It has a deflection-load characteristic of the following curve. Therefore, by setting the area near the front end of this range a (X[F]) to correspond to the stall rotation speed, fluctuations in the stall rotation speed can be minimized even with variations in component dimensions and increased friction plate wear. Furthermore, the structure is simple and the assembly is easy.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an embodiment to which the present invention is applied, Fig. 2 is a cross-sectional view of the clutch, Fig. 3 is a view of the multi-latch housing and clutch boss in the direction of the ■ arrow, and Fig. 4 is a disc spring deflection diagram. It is a load characteristic diagram. 26...Clutch, 72...Clutch plate, 72a
s72b...clutch plate as end plate, 74...friction plate, 82...weight, 84...disc spring. □ Patent applicant Yamaha Motor Co., Ltd.: Agent Patent attorney Fumio Yamada Figure 4 11: Procedural amendment dated August 6, 1932 Kazuo Wakasugi, Commissioner of the Patent Office'1. Display of the case 1982 Patent Application No. 122435 2, Title of the invention Far-end type multi-plate &7793, Person making the amendment Relationship to the case Patent applicant 7 Rigana Address 2500 Shingai, Iwata City, Shizuoka Prefecture Name ( Name) (AO7) Yamaha Motor Co., Ltd. Representative Hisao Koike 4° Representative Person 〒1osm Story 03 (591) 75
565. Date of amendment order Vol. 6. Number of inventions increased by amendment 07. Specification subject to amendment" Chen Li 8. Contents of amendment The application and specification shall be inscribed as shown in the attached sheet.

Claims (1)

[Claims] One of a plurality of clutch plates and friction plates is locked to a clutch housing and the other to a clutch boss, and one end plate of these clutch plates and friction plates is pressed by displacement due to centrifugal force of a weight, while the other end is pressed. In a centrifugal multi-plate clutch in which a plate is pressed by a clutch spring, the clutch spring is a disc spring, and the disc spring has deflection/load characteristics in the form of a substantially cubic curve in which the load change is approximately zero within a predetermined deflection range. A centrifugal multi-disc clutch featuring the following features: