JPH0417870Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a power transmission mechanism for small vehicles such as motorcycles and tricycles, and particularly relates to a centrifugal clutch in the power transmission mechanism.

Conventional technology Transmission pulleys, chain sprockets, gears,
A power input member such as an input shaft, a power output member such as an output shaft, a gear, a chain sprocket, a transmission pulley, a clutch inner integrally connected to one of these members, and a clutch inner integrally connected to the other member. It is located between the connected bottomed cylindrical clutch outer, the clutch inner and the clutch outer, and as the rotational speed of the power input member increases, the clutch inner and the clutch outer are integrally connected to generate power. A centrifugal clutch is known, which consists of a friction transmission member that transmits the oscillation force, and in which all the members rotate on the same axis. In such a centrifugal clutch, rotation of the power input member causes the clutch inner or clutch outer to rotate,
When the rotational speed increases, the centrifugal force acting on the centrifugal weight causes the clutch inner and clutch outer to be integrally connected via the friction transmission member.
The outer clutch or inner clutch rotates, and the power output member integrally connected to the outer clutch or inner clutch rotates.

Problems that the invention aims to solve: However, when the vehicle starts, frictional heat is generated at the frictional contact area before the clutch inner and clutch outer are connected together (the so-called half-clutch state). If the condition continues, the temperature of the centrifugal clutch will rise.

The present invention was devised against this technical background, and its purpose is to forcefully cool the outside air by directly passing it through the friction contact part of the centrifugal clutch, and to cool the air after passing through it. Cooling air is discharged near the wrapping portion of the V-belt to cool the wrapping portion and remove dust at the wrapping portion.

Means and Effects for Solving the Problems In accordance with the above object, the present invention provides a power input member connected to a V-belt type power transmission device that transmits power from an engine mounted on a small vehicle, a power output member, A clutch plate integrally coupled to the power input member, a bottomed cylindrical clutch outer integrally coupled to the power output member, and located between the clutch outer and the clutch plate, In a centrifugal clutch comprising a friction transmission member that integrally connects the clutch outer and the clutch plate to transmit power as the rotational speed of the member increases, and in which all the members rotate on the same axis, the V-belt The output pulley and the friction transmission member of the power transmission device are provided adjacent to each other, and a plurality of openings are formed in the bottom wall of the clutch outer, and the clutch outer is located between the clutch outer and the clutch plate, and the clutch outer is provided with a friction transmission member adjacent to the output pulley. A plurality of blades oriented in a substantially radial direction are integrally provided on the clutch plate integrally connected to the member, and cooling air generated by the blades is applied to the friction portion between the clutch outer and the friction transmission member. The centrifugal clutch is configured such that the power generated by the internal combustion engine is discharged near the output pulley of the V-belt power transmission device after passing through the V-belt power transmission device. The power is transmitted to the input member through the transmission device, and the rotation of the input member rotates the clutch plate provided with the blades, and outside air is supplied between the clutch outer and the clutch plate through the opening formed in the bottom wall of the clutch outer. is introduced, the friction contact part is directly exposed to the cooling air and cooled, and the cooling air after passing through the part is discharged near the output side pulley of the V-belt type power transmission device. cooling and removing dust that adheres to and moves on the belt in this area.

Embodiment Hereinafter, an embodiment of the present invention shown in FIGS. 1 to 4 will be described. FIG. 1 shows a unit swing type power unit 10 of a tricycle as a sectional view. In power unit 10,
The engine 12 and the transmission case 14 are integrally formed. Inside the transmission case 14, a crankshaft 16, a main shaft 18, a subshaft 20, a left axle 22, and a right axle 24 are arranged in order from the front.

A V-belt type power transmission mechanism is provided to transmit the power of the crankshaft 16 to an inner cylinder 38, which is a power input member described later. 26, an output side variable pulley 32 on the main shaft 18, and a V-belt 28 spanned between these pulleys 26, 32. A centrifugal clutch 30 including a variable pulley 32 is disposed on the main shaft 18, the detailed structure of which is shown in FIG.

An inner cylinder 38 is rotatably supported on the main shaft 18 via a needle bearing 34 and a ball bearing 36, and a fixed pulley half 33A is fixed to one end of the inner cylinder 38. An outer cylinder 40 is fitted onto the outer periphery of the inner cylinder 38 so as to be slidable in the axial direction, and a movable pulley half 33B is fixed to one end of the outer cylinder 40. The outer cylinder 40 includes an elongated hole 42 extending in the axial direction, and a guide pin 44 press-fitted into the inner cylinder 38 is located in the elongated hole 42 . Therefore, the outer cylinder 40 can be guided by the guide pin 44 and reciprocated in the axial direction. A cylindrical cover 46 is fitted onto the outer cylinder 40 via an O-ring, and the elongated hole 42 is oil-tightly covered by the cylindrical cover 46. One end portion of the cylindrical cover 46 is folded back toward the outside, and the folded portion supports one end of the compression coil spring 48 . The other end of this compression coil spring 48 is
It is supported by a clutch plate 52 described later,
The elastic force acts on the movable pulley half 33B through the cylindrical cover 46, urging the member 33B toward the fixed pulley half 33A.

Then, the other end of the inner cylinder 38 (variable pulley 32
A clutch plate 52 of the clutch inner 50 and a wing body 54 that covers one side of the clutch plate 52 are fixed with a nut 51 to the end (on the side to which no mark is attached). The wing body 54 is formed of a dish-shaped wing base plate 56 and a large number of wing pieces 58 protruding from its outer peripheral edge (see FIGS. 3 and 4. However, FIG. FIG. 4 is a single-piece view of the wing body 54, and FIG. 4 is a sectional view taken along the line - The wing piece 58 is the third
As shown in the figure, it is oriented almost radially, but
Strictly speaking, it is oriented in a direction inclined by a small angle .degree. with respect to the radial direction line R.

On the other hand, a clutch weight 62 is swingably supported by the clutch plate 52 via a support pin 60, and centrifugal force generated by the rotation of the clutch plate 52 causes a centrifugal force to be applied to the outer periphery of the clutch weight 62. The clutch shoe 64 is in contact with the inner circumferential surface of a clutch outer 66 having a cylindrical shape with a bottom. The clutch outer 66 is spline-engaged with the main shaft 18 and is prevented from coming off the main shaft 18 by a nut 70. Also,
A plurality of openings 68 are provided in the bottom wall of the clutch outer 66.
is formed.

The centrifugal clutch 30 of this embodiment is constructed as described above, and when the engine 12 is in operation,
While the crankshaft 16 is rotating at low speed (during idling), the variable pulley 26 and the V-belt 2
The variable pulley 32 which is driven and rotated via the variable pulley 32, the inner cylinder 38 which rotates together with the variable pulley 32, and the clutch plate 52 also rotate at a low speed, so that the clutch shoe 64 of the clutch weight 62 contacts the clutch outer 66. The clutch outer 66 and the main shaft 18 that mesh with the clutch outer 66 do not rotate, and the vehicle remains stopped. During this time, the wing body 54 is also rotating together with the clutch plate 52, and since the wing body 54 rotates in the direction of arrow A in FIG. An air flow like this is generated, and external air is taken into the clutch outer 66 through the opening 68 of the clutch outer 66. After the air flows toward the outer periphery of the wing base 56, the clutch outer 66
It flows in the axial direction along the inner surface of the cylindrical wall and is discharged near the variable pulley 32 (see arrow B in FIG. 2).

Next, when starting the vehicle, the crankshaft 16
When the rotational speed of the crunch inner 50 increases and accordingly the rotational speed of the crunch inner 50 increases to a certain stage,
The clutch weight 62 swings around the support pin 60, and the clutch shoe 64 comes into sliding contact with the cylindrical wall of the clutch outer 66. clutch weight 62
While there is a rotational speed difference between the clutch outer 66 and the clutch outer 66 (half-clutched state), the clutch 64 makes frictional sliding contact with the inner surface of the cylindrical wall of the clutch outer 66, so frictional heat is generated at the sliding contact. As mentioned above, due to the air flow, the generated frictional heat is dispelled, effectively suppressing the temperature rise of the clutch inner 50 and clutch outer 66, and as a result, the friction of the clutch shoe 64 is suppressed, improving its durability. improves.

When the rotational speed of the clutch inner 50 further increases, the clutch weight 62 comes into contact with the clutch outer 66 at its clutch shoe 64 portion under strong pressure, and eventually the rotational speed difference between the clutch inner 50 and the clutch outer 66 disappears. ,
Both rotate integrally, and the power of the engine 12 is transmitted to the main shaft 18, the counter shaft 20, the left vehicle 22, and the right vehicle 2.
4 and is transmitted to the rear wheels. Even in this running state, the air flow (arrow B) exists and cools the friction negotiation part, but in addition, the blades 58 function as heat radiators, and the friction transmitted to the clutch weight 62 and clutch plate 52 is Heat is dissipated effectively.

The cooling air that has passed through the frictional contact between the clutch shoe 64 attached to the clutch plate 52 and the clutch outer 66 is discharged to the vicinity of the output variable pulley 32 of the V-belt type power transmission device as described above. It is possible to cool the part, that is, the part where the belt is wound, and to blow off and remove the dust that is attached to and moves on the belt.

In the above embodiment, the variable pulley 32 and the main shaft 18 are used as a power input member and a power output member, respectively, but depending on the structure of the centrifugal clutch, both may be used as a power output member and a power input member, respectively. It is also possible to do so. In that case,
The blade pieces are attached to the clutch outer that rotates together with the power input member.

Effects of the Invention As is clear from the above explanation, the centrifugal clutch of the present invention is located between the clutch outer, which has a bottomed cylindrical shape with a plurality of openings in its bottom wall, and the clutch plate, and is connected to the power input member. Since a plurality of blades are provided on the integrally connected clutch plate, when the power input member rotates, external air is introduced into the inside of the centrifugal clutch through the opening by the action of the blades, and the friction area between the clutch outer and the friction transmission member is The external cooling air comes into direct contact with the friction area, ensuring that this friction area is cooled.

In addition, in the present invention, since a plurality of blades are provided on the clutch plate that is integrated with the power input member, the blades are always present not only when the clutch is disengaged but also when the clutch is in a half-clutch state where the frictional parts need to be sufficiently cooled. Since the clutch rotates and generates cooling air, the clutch can be sufficiently cooled and friction at friction parts can be suppressed more reliably. Furthermore, since there is pulsation in the engine, the V-belt cannot rotate at a constant speed or constant acceleration, and is constantly accelerated and decelerated, causing slips on the contact surface between the belt and the pulley. Similar to the friction transmission member of the clutch, heat generation occurs due to sliding friction, but the heat generating part (pulley) of the belt is adjacent to the friction transmission member of the clutch.
Since the wind passing through the friction contact portion of the clutch is cooled by contact with the heat generating portion of the belt and is discharged, heat generation in this portion can be suppressed and friction can be reduced.

Further, as described above, slips always occur on the contact surfaces between the belt and the pulley, and dust is generated due to friction, but when this dust moves with the belt, slips are more likely to occur, resulting in a problem of reduced transmission efficiency.

However, in the present invention, the cooling air hits the pulley and blows away the moving dust adhering to the belt, so the above-mentioned problems can be avoided.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a tricycle engine equipped with a centrifugal clutch according to an embodiment of the present invention, Fig. 2 is an enlarged view of its main parts, and Fig. 3 is a front view of a wing body that is a part of the centrifugal clutch. FIG. 4 is a sectional view taken along the - line in FIG. 3. 10...power unit, 12...engine,
18...Main shaft, 30...Centrifugal clutch, 32...
Variable pulley, 54... Wing body, 58... Wing piece, 6
2...Clutch weight, 64...Clutch shoe, 66...Clutch outer, 68...Opening.

Claims (1)

[Scope of utility model registration request] A power input member connected to a V-belt type power transmission device that transmits power from an engine mounted on a small vehicle, a power output member, a clutch plate integrally connected to the power input member, and a clutch plate connected to the power output member. A bottomed cylindrical clutch outer that is integrally connected is located between the clutch outer and the clutch plate, and integrally connects the clutch outer and the clutch plate as the rotational speed of the power input member increases. In a centrifugal clutch, which consists of a friction transmission member that transmits power, and in which all the members rotate on the same axis,
an output pulley and a friction transmission member of the V-belt type power transmission device are provided adjacent to each other, a plurality of openings are formed in the bottom wall of the clutch outer, and the clutch outer is located between the clutch outer and the clutch plate; A plurality of blades oriented in a substantially radial direction are integrally provided on the clutch plate integrally connected to the power input member, and cooling air generated by the blades connects the clutch outer and the friction transmission member. A centrifugal clutch characterized in that it is configured to directly touch and pass through a frictional part and then be discharged near an output pulley of the V-belt type power transmission device.