JP2002295523A - Automatic centrifugal clutch for start - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save energy and improve productivity by forming a wall thickness of the clutch housing into a thin shape to implement extensive miniaturization in an automatic centrifugal clutch for start in which a plurality of clutch plates are alternately laminated and pressed each other to be set to a clutch engagement state by increasing centrifugal force acting on a weight provided in a clutch housing. SOLUTION: The clutch housing is formed by press molding to a plate. During the press molding, an opening for installation of the weight is simultaneously formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an engine for automatically controlling the output of a crankshaft of an internal combustion engine mounted in a vehicle to a cut-off state at a low speed above a predetermined rotation speed and a connection state at a high speed by a centrifugal force acting on a weight. The present invention relates to an automatic centrifugal clutch for starting that is selectively switched.

[0002]

2. Description of the Related Art In a conventional automatic centrifugal clutch for starting (Japanese Patent Publication No. 2-29892), a bowl-shaped clutch housing integrally fitted to a crankshaft of an internal combustion engine is made of steel. Since it is a cast product, it has low mass productivity and is thick, and when it is made of light alloy, it is made of die-cast, so the mold cost is high and it is thick. And it is difficult to reduce the weight and cost.

[0003]

SUMMARY OF THE INVENTION The invention of the present application relates to an improvement of an automatic centrifugal clutch for starting which overcomes such difficulties. The invention according to claim 1 is connected to a crankshaft of an internal combustion engine. The plurality of clutch plates respectively engaged with the clutch housing and the driven member are alternately overlapped, and the plurality of clutch plates are pressed against each other by an increase in centrifugal force acting on a weight provided in the clutch housing. In the starting automatic centrifugal clutch which is brought into the clutch connected state, the clutch housing is formed by press-forming a plate material, and at the time of this press-forming, the opening for mounting the weight is simultaneously formed. It is characterized by having.

According to the first aspect of the present invention, since the clutch housing is formed by press-forming a plate material, the thickness of the clutch housing becomes extremely thin, so that the weight can be significantly reduced. Since it does not rely on casting or die casting, it is possible to save energy and improve productivity.

[0005] Further, since the openings for attaching the weights are simultaneously formed at the time of press molding, the number of processing steps can be reduced, and the cost can be greatly reduced.

According to a second aspect of the present invention, the bearing for supporting the swinging shaft of the weight is constituted by a clutch housing main body and a cut and raised piece cut and raised from the clutch housing. Since the raised piece is formed at the same time as the clutch housing press molding, the number of parts and the number of processing steps of the automatic centrifugal clutch for starting are further reduced, and further reduction in weight and cost can be achieved.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention shown in FIGS. 1 to 7 will be described below.

As shown in FIGS. 1 and 2, a main body of a single-cylinder OHC four-stroke cycle internal combustion engine 0 mounted on a motorcycle (not shown) has a cylinder hole 5 substantially in front (in FIG. (Upper in FIG. 2) a cylinder block 1 oriented in the horizontal direction, a cylinder head 2 arranged at the front end of the cylinder block 1, and the cylinder block 1
A right crankcase 3 and a left crankcase 4 arranged at the rear end of the right and left crankcases. The right and left right crankcases 3 and the left crankcase 4 are mutually connected by bolts (not shown). The bolts 6 are screwed into the right crankcase 3 and the left crankcase 4 through the cylinder head 2 and the cylinder block 1 from the front of the vehicle body, and the cylinder block 1, the cylinder head 2, the right crankcase 3, and The left crankcase 4 is integrally connected.

As shown in FIG. 2, a piston 7 is slidably fitted in a cylinder hole 5 of the cylinder block 1, and a right and left crankcase 3 and a left crankcase 4 have a vehicle width. Crankshaft 8 oriented in the direction
Is rotatably supported via a ball bearing 9, and the piston 7 and the crank shaft 8 are connected to each other by a connecting rod.
The crankshaft 8 is rotated clockwise in FIG. 1 in conjunction with the reciprocation of the piston 7.

Further, a main shaft 11 and an output shaft 12 are rotatably supported by the right crankcase 3 and the left crankcase 4 in parallel with the crankshaft 8 (FIG. 1). The automatic centrifugal clutch 13 for starting shown in FIG. 3 is disposed, and a switching clutch 36 shown in FIG. 3 is disposed at the right end of the main shaft 11, and a gear (not shown) is mounted on the main shaft 11 and the output shaft 12. A drive sprocket (not shown) is attached to the left end of the output shaft 12 protruding leftward from the left crankcase 4, and a driven sprocket (not shown) is integrated with a rear axle integrated with a rear wheel (not shown). And an endless chain (not shown) is bridged between the drive sprocket and the driven sprocket.
And when the switching clutch 36 is connected,
By selective engagement of the gears of the main shaft 11 and the output shaft 12, a rear wheel (not shown) is rotationally driven at a predetermined gear ratio.

In the automatic centrifugal clutch 13 for starting, FIG.
As shown in FIG. 4, a centrifugal clutch inner 14 is rotatably fitted to the right side of the crankshaft 8, and is located near the outer end of the centrifugal clutch inner 14 and has a clutch center at the right end of the crankshaft 8. 15 is splined,
A clutch center 15 is integrally connected to the crankshaft 8 by a nut 16 screwed to the right end of the crankshaft 8.
The inner peripheral surface 14b of the circular concave portion of the outer disk portion 14a of the centrifugal clutch inner 14, and the outer peripheral surface 15 of the clutch center 15
As shown in FIGS. 3 and 6, a retainer 18 of a one-way clutch 17 is interposed between the
As shown in FIG. 6, the roller holding holes 18a are formed at regular intervals in the circumferential direction.
The roller 19 is loosely fitted to the roller 8a, and a clutch cam concave surface 15b is formed on the outer peripheral surface 15a of the clutch center 15, as shown in FIGS.

As shown in detail in FIG. 7, the clutch cam concave surface 15b is gently inclined radially from the bottom in the clockwise direction, and is inclined in the counterclockwise direction from the bottom. When the clutch center 15, that is, the crankshaft 8 rotates clockwise in FIG. 6 (the single-cylinder OHC four-stroke cycle internal combustion engine 0 rotates forward), the rotational torque of the clutch center 15 decreases. When the clutch center 15 rotates counterclockwise in FIG. 6 (the single-cylinder OHC four-stroke cycle internal combustion engine 0 reverses) without being transmitted to the centrifugal clutch inner 14, the rotational torque of the clutch center 15 is applied to the centrifugal clutch inner 14. When transmitted or when the centrifugal clutch inner 14 rotates clockwise in FIG. Torque clutch center
15 to be transmitted.

The clutch center 15 and the retainer
A positioning ring-shaped spring 20 is interposed between the clutch center 18 and the spring force of the spring 20 so that the roller holding hole 18a of the retainer 18 can return to a position facing the bottom of the clutch cam concave surface 15b of the clutch center 15. It has become.

Further, a steel bowl-shaped clutch housing 21 is integrally joined to the outer peripheral surface of the right side of the clutch center 15 by welding, and the clutch housing 21 is a press-formed product.

The outer peripheral portion 21b of the disc-shaped portion 21a of the clutch housing 21 formed by the press molding is bent substantially to the left at a right angle in cross section with respect to the disc-shaped portion 21a. As shown, overhangs 21c are formed at equal intervals in the circumferential direction, and an opening 21d is formed at a position near the center of every other overhang 21c among the overhangs 21c, An engaging claw 21 e for holding the support ring 25 is cut and raised in the middle of the opening 21 d to be opened, and the disc-shaped portion 21 of the clutch housing 21 is cut.
a, the outer peripheral portion 21b, the overhang portion 21c, the opening 21d, and the locking claw 21e are formed at the same time when the clutch housing 21 is pressed.

The disk-shaped portion 2 of the clutch housing 21
Clutch center 15 and nut located at the center of 1a
A cover 22 for covering the clutch housing 21 is integrally attached to the disc-shaped portion 21a of the clutch housing 21 with bolts 23, and a weight cam 24 is loosely fitted into an opening 21d of the clutch housing 21. The weight cam 24 is pivotally supported by a support ring 25 sandwiched between the portion 21a and the locking claw 21e.

Further, as shown in FIG. 6, a large number of engaging recesses 14c are formed in the outer peripheral portion 14a of the centrifugal clutch inner 14 at equal intervals in the circumferential direction. Clutch plate in mating recess 14c
26 are fitted with the inner peripheral projections 26a. Friction plates 27 are integrally attached to both side surfaces of the clutch plate 26.

Further, as shown in FIG. 3, the outer peripheral projections 28a of the two pressure plates 28 are provided on the overhanging portions 21c of the clutch housing 21.
And the two pressure plates 28
Among them, a guide pin 29 is integrally caulked in several places in the circumferential direction on the right pressure plate 28 toward the left, and the tip of the guide pin 29 is loosely fitted to the left pressure plate 28. And a coil spring is attached to the guide pin 29.
The spacer 30 is integrally crimped to the left side surface of the right pressure plate 28 at several places in the circumferential direction. The inner surface of the overhang portion 21c of the clutch housing 21 functions as a stopper, and the pressure plate 28 rotates integrally with the clutch housing 21.

When the crankshaft 8 and the clutch center 15 are stopped or rotating at a predetermined rotational speed or less, a large centrifugal force does not act on the weight cam 24, and the clutch plate 26 and the pressure plate 28 As shown in FIG. 3, the clutches are separated from each other and the clutch is disconnected.

Further, when the crankshaft 8 and the clutch center 15 rotate clockwise in FIG. 5 and FIG. 6 at a predetermined rotational speed or more, the weight cam shown in FIG. 4 swings in the clockwise direction and tilts as shown in FIG. 4. The right pressure plate 28 is pushed leftward by the tilt of the weight cam 24, and the clutch plate 26 and the pressure plate
28 is pressed against each other via a friction plate 27, and the rotational torque of the crankshaft 8, that is, the clutch center 15 is transmitted to the centrifugal clutch inner 14 by the frictional force of the pressing.

Further, an output gear 33 is formed integrally with the left end of the centrifugal clutch inner 14, and a serration gear 34 is disposed adjacent to the output gear 33. The formed gear 38 is meshed with the output gear 33 and the serrated gear 34, and the serrated gear 34 is constantly pressed against the power non-transmission side gear of the gear 38 of the switching clutch 36 by the spring force of the spring 35,
Backlash is removed.

Further, a kick starter gear (not shown) or an output gear of a starter motor (not shown) is meshed with the output gear 33 integrated with the centrifugal clutch inner 14, so that a kick pedal (not shown) is depressed or the starter motor is started. 5, a clockwise torque is applied to the output gear 33, the one-way clutch 17 is connected, and the crankshaft 8 is driven to rotate clockwise in FIG.
The single cylinder OHC 4-stroke cycle internal combustion engine 0 is started.

Since the embodiment shown in FIGS. 1 to 7 is constructed as described above, when the crankshaft 8 is stopped or is rotating at a predetermined rotational speed or less, a large centrifugal force is applied to the weight cam 24. The force does not work, and the automatic centrifugal clutch 13 for starting is in a disconnected state.

When the rotation speed of the crankshaft 8 exceeds a predetermined rotation speed, the pressure plate 28 is pressed against the clutch plate 26 by the centrifugal force acting on the weight cam 24, and the starting automatic centrifugal clutch 13 is connected. The torque of the crankshaft 8 is transmitted to the clutch outer 37 of the switching clutch 36.

The clutch housing 21 of the starting automatic centrifugal clutch 13 is formed by stamping and pressing a steel plate.
A disk-shaped portion 21a, an outer peripheral portion 21b of the clutch housing 21,
Since the overhang portion 21c, the opening 21d, and the locking claw 21e are simultaneously and integrally formed, a large number of complicated molds are not required, the number of parts and the number of processing steps can be reduced, and the clutch housing 21 is formed of a thin copper plate. As a result, the productivity that can be configured can be increased, so that the weight can be reduced and the cost can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is an external view of a single-cylinder OHC four-stroke cycle internal combustion engine provided with an automatic centrifugal clutch for starting according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part of the internal combustion engine.

FIG. 3 is a longitudinal sectional view of an automatic centrifugal clutch for starting according to an embodiment of the present invention.

FIG. 4 is an operation explanatory view of the automatic centrifugal clutch for starting.

FIG. 5 is a front view of a housing of the automatic centrifugal clutch for starting.

FIG. 6 is a cross-sectional view of a housing of the automatic centrifugal clutch for starting.

FIG. 7 is a partially enlarged sectional view of a one-way clutch of the automatic centrifugal clutch for starting.

[Explanation of symbols]

0 ... single cylinder OHC 4-stroke cycle internal combustion engine, 1 ...
Cylinder block, 2 ... cylinder head, 3 ... right crankcase, 4 ... left crankcase, 5 ... cylinder bore, 6 ... bolt, 7 ... piston, 8 ... crankshaft, 9 ...
Ball bearing, 10 connecting rod, 11 main shaft, 12 output shaft, 13 automatic centrifugal clutch for starting, 14 centrifugal clutch inner, 14a outer disk portion, 14b inner circumferential surface of circular recess, 14c engagement Recessed part, 15: clutch center, 15a: outer peripheral surface, 15b: concave surface of clutch cam, 16: nut, 17: one-way clutch, 18: retainer, 18a: roller holding hole, 19: roller, 20: spring, 21: clutch housing, 21a: disk-shaped part, 21b: outer peripheral part, 21c ...
Overhang, 21d ... opening, 21e ... locking claw, 22 ... cover,
23… bolt, 24… weight cam, 25… support ring, 26…
Clutch plate, 26a ... circumferential projection, 27 ... friction plate, 28 ...
Pressure plate, 28a: outer peripheral projection, 29: guide pin, 30: coil spring, 31: spacer, 33: output gear, 34: serration gear, 35: spring, 36: switching clutch, 37: clutch outer, 38: gear .

[Procedure amendment]

[Submission date] April 4, 2001 (2001.4.4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

As shown in FIGS. 1 and 2, a main body of a single-cylinder OHC four-stroke cycle internal combustion engine 0 mounted on a motorcycle (not shown) has a cylinder hole 5 substantially in front (in FIG. (Upper in FIG. 2) a cylinder block 1 oriented in the horizontal direction, a cylinder head 2 arranged at the front end of the cylinder block 1, and the cylinder block 1
Right more becomes crankcase 3 and leftward crankcase 4 left split disposed at the rear end of the right side crankcase 3 and leftward crankcase 4 of the right and left split are coupled to each other by not shown bolts At the same time, the right crankcase 3 and the left crankcase 4 pass through the cylinder head 2 and the cylinder block 1 from the front of the vehicle body.
The cylinder block 1, the cylinder head 2, the right crankcase 3, and the left crankcase 4 are integrally connected to each other by bolts 6 screwed to the cylinder block 1.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

A main shaft 11 and an output shaft 12 are rotatably supported by the right crankcase 3 and the left crankcase 4 in parallel with the crankshaft 8 (FIG. 1). 3 is disposed, and a switching clutch 36 shown in FIG. 3 is disposed at the right end of the main shaft 11, and a gear (not shown) is connected to the main shaft 11 and the output shaft 12. is provided, it is shown to the left end of the output shaft 12 protruding from the left crankcase 4 to the left
No drive sprocket is mounted integrally driven sprocket (not shown) to the rear axle of the wheel integral after (not shown) is integrally attached to an endless chain to the drive sprocket and the driven sprocket (not shown) is passed rack Automatic centrifugal clutch for starting 13
And when the switching clutch 36 is connected,
By selective engagement of the gears of the main shaft 11 and the output shaft 12, a rear wheel (not shown) is rotationally driven at a predetermined gear ratio.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Kaneshiro 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Masashi Rikui 1-4-1 Chuo, Wako-shi, Saitama No. F-term in Honda R & D Co., Ltd. (reference) 3J068 AA01 AA05 BA13 BB05 CA03 CB03 GA19

Claims (2)

[Claims] A clutch housing connected to a crankshaft of an internal combustion engine and a plurality of clutch plates respectively engaged with a driven member are alternately overlapped, and a centrifugal force acting on a weight provided on the clutch housing is reduced. In the starting automatic centrifugal clutch in which the plurality of clutch plates are pressed against each other by the increase to be in a clutch connected state, the clutch housing is configured by performing press forming on a plate material. An automatic centrifugal clutch for starting, characterized in that a weight mounting opening is formed simultaneously. 2. A bearing portion for supporting a swing shaft of the weight is constituted by the clutch housing main body and a cut-and-raised piece cut and raised from the clutch housing,
2. The automatic centrifugal clutch for starting according to claim 1, wherein said cut-and-raised pieces are formed simultaneously with said clutch housing press molding.