JPH0467008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cooling fan for a forced air cooling engine.

(Prior art and its problems) The cooling fan of a forced air cooling engine installed in conventional vehicles, especially motorcycles, is arranged on the end face of the rotor of an alternator that is rotated by the engine, and its outer diameter is equal to that of the alternating current generator. The fins are made to have a diameter larger than that of the rotor of the machine, and a large number of fins are erected radially inward from the outer periphery of the end surface at predetermined intervals in the circumferential direction on the end surface that contacts the end surface of the rotor.
However, since the end surface of the cooling fan is formed to have a larger diameter than the opposing end surface of the rotor, when the cooling fan rotates with the rotation of the rotor, the fin-standing portion of the cooling fan, especially near the peripheral edge, may be damaged. Vibration is likely to occur, and rattling occurs between this peripheral portion and the rotor, which is likely to cause noise.

(Object of the Invention) The present invention has been made in view of the above-mentioned points, and it makes it difficult for the vibrations of the cooling fan disposed on the rotor of the generator of a vehicle to be transmitted to the rotor when the cooling fan is rotated. This invention provides a cooling fan for a forced air-cooled engine that effectively cools a rotor and the like.

(Summary of the Invention) In order to achieve the above object, the present invention provides a cooling fan on the outer end surface of the rotor of the generator, which is provided at the end of the rotating shaft driven by the engine and housed in the storage member. In a cooling fan for a forced air-cooled engine that cools the engine by air flow generated as the rotor rotates, the outer diameter of the end surface of the fan that comes into contact with the end surface of the rotor is formed to be smaller than the outer diameter of the end surface of the rotor. , a plurality of fins are erected on the peripheral edge of the end face of the fan at predetermined intervals in the circumferential direction and approximately perpendicular to the end face, and each of these fins extends radially from the peripheral edge to the end face of the rotor. An outer ring is provided that extends further outward and connects at least the outer portions of the fins with respect to the end surface of the rotor on the side opposite to the engine, and the housing member and the rotor are provided with an outer ring that connects at least the outer portions of the fins with respect to the end surface of the rotor. The present invention provides a cooling fan for a forced air-cooled engine, which is characterized by being provided with an opening through which a wind flow flows.

(Embodiment of the Invention) An embodiment of the present invention will be described below in detail based on the accompanying drawings.

As shown in FIGS. 1 and 2, for example, an alternating current generator (hereinafter simply referred to as a generator) 3 is attached to one end side of a crankshaft 2 of an engine 1 of a vehicle.
A cooling fan 5 is fixed to the end surface 4a of the rotor 4 of the generator 3 with a plurality of bolts 6.
The rotor 4 is formed in a bowl shape with an opening 4A facing the engine 1, and is housed in a crankcase 8 serving as a housing member. This crankcase 8 is also provided with an opening 8A.
1 cooling fan 5 is installed on the outer end surface 4a of this bowl-shaped rotor 4.
is fixed to. A shroud 7 is attached to the crankcase 8 on the outside of the cooling fan 5 so as to cover the engine 1 and the cooling fan 5.
A fan cover 9 having a duct 9a is fitted onto the shroud 7 from the outside.

The cooling fan 5 has a substantially disk shape with a substantially central portion slightly bulging outward so as to cover the mounting bolt 10 of the rotor 4 to the crankshaft 2.
As described above, the end surface 5a of the rotor 4 facing the cooling fan 5 is screwed at a predetermined portion with the bolt 6 to the end surface 4a of the rotor 4 facing the cooling fan 5. The end surface 5a is set to have a smaller diameter than the end surface 4a of the rotor 4, and substantially rectangular fins 5b are provided on the peripheral edge of the end surface 5a at a predetermined interval in the circumferential direction and facing outward in the radial direction. A predetermined number of holes extend substantially perpendicularly to the end surface 4a of 4. A gap portion 5A between each fin 5b in the peripheral portion of the end surface 4a of the rotor 4 corresponds to an air outlet of the cooling fan 5. The opening 4A of the rotor 4 and the air outlet 5A of the cooling fan 5 communicate with each other. The vicinity of the base of each end surface 5b' of each of these fins 5b facing the end surface 4a of the rotor 4 is in pressure contact with the end surface 4a of the rotor 4, respectively. Furthermore, an annular outer ring 11 is provided radially inward from the outer edge on the shroud 7 side end surface 5b'' of each of these fins 5b to reinforce each fin 5b.
is integrally formed of a synthetic resin member or the like.

On the other hand, an inlet 7a provided facing the cooling fan 5 of the shroud 7 attached to the crankcase 8 has a cylindrical shape with a peripheral edge 7a' projecting outward. A flange 7b is provided around the inner open end facing the cooling fan 5 so as to be able to face the cooling fan 5 with a slight gap in order to straighten the introduced outside air. A fan cover 9 having a duct 9a formed therein as described above is fitted to the outside of the peripheral edge 7a' of the intake port 7a of the shroud 7.

In this configuration, when the crankshaft 2 of the engine 1 rotates, the rotor 4 and cooling fan 5 of the generator 3 rotate together. When the cooling fan 5 rotates, outside air is introduced from the duct 9a of the fan cover 9, and the introduced outside air further passes through the inlet 7a of the shroud 7 and reaches the outlet 5A of the cooling fan 5.
It is blown out in the direction of arrow A in FIG. 1, guided along the shroud 7 to the cylinder peripheral wall 12 of the engine 1, and cooled there.

Furthermore, since the end surface 5a of the cooling fan 5 is formed to have a smaller diameter than the end surface 4a of the rotor 4, each end surface 5b' of each fin 5b extending radially outward from the peripheral edge of the end surface 5a is Since each fin 5b has a free end, that is, the portion of each fin 5b that is not connected to the peripheral edge of the end surface 5a is hollowed out, a portion of the outside air that is introduced from the outside and passes through the air outlet 5A is removed. flows in the directions of arrows B and C in the figure through these hollowed out parts, and the introduced outside air flowing in the direction of arrow B cools the engine 1 over a wide range together with the introduced outside air flowing in the direction of arrow A, Arrow C
The introduced outside air flowing in the direction is from the opening 8A of the crankcase 8, and is connected to the outer periphery of the rotor 4 and the crankcase 8.
It flows between the guide 8a protruding from the rotor 4, and further flows into the opening 4A of the rotor 4 to cool the inside of the rotor 4 and the generator 3.

That is, the outside air introduced into the shroud 7 by the rotation of the cooling fan 5 flows not only in the direction of arrow A in the figure but also in the directions of arrows B and C, and the introduced outside air flowing in the direction of arrow B flows through the guide 8a of the crankcase 8. The heat trapped near the base of the engine is guided out to cool the engine 1 together with the introduced outside air flowing in the direction of arrow A, and the introduced outside air flowing in the direction of arrow C cools the inside of the rotor 4 and generator 3, and then both are released from a duct (not shown). Exhausted. Here, the direction of movement of the outside air that has passed between each fin 5b is regulated by the outer ring 11,
It flows only in approximately three directions: the direction of arrows A, B, and C. In particular, the outer ring 11 prevents outside air from flowing in the direction opposite to the C direction. Thereby, the engine 1 and generator 3 are effectively cooled. In addition, each fin 5b protrudes from the cooling fan 5 fixed to the end surface 4a of the rotor 4, which tends to vibrate, and only the base of one side of each fin 5b is supported, so if it is left as it is, vibration will not occur. Although this is likely to occur, since the protruding portions of each fin 5b are connected by the outer ring 11, vibration of the fins 5b is effectively suppressed.

On the other hand, the rotor 4 of each fin 5b of the cooling fan 5
The rotor 4 and the fin 5b are located near the base of the side end surface 5b'.
, and a part of each tip (free end) side is in pressure contact with the end surface 4a of the rotor 4, so even when the rotor 4 and the cooling fan 5 rotate, the fins 5b do not touch other than the above-mentioned contact portion. The outside air introduced from the cooling fan 5 passes through the cooling fan 5, and the centrifugal force decreases as the mass of the peripheral edge of the cooling fan 5 decreases, and vibrations of the cooling fan 5 due to rotation are reduced. Along with this, the end surface 4a of the rotor 4
The noise generated between the cooling fan 5 and the cooling fan 5 is also reduced.

Furthermore, the annular outer ring 11 that connects one end of each fin 5b of the cooling fan 5 and the flange 7b of the intake port 7a of the shroud 7 make it possible for each fin 5b to
The occurrence of turbulent flow caused by gaps, steps, etc. between the intake port 7a of the shroud 7 and the opening end of the intake port 7a of the shroud 7 is reduced.
Accordingly, the cooling efficiency of the cooling fan 5 is improved and the noise is reduced.

(Effects of the Invention) As detailed above, according to the present invention, the amount of vibration caused by the rotation of the cooling fan that is directly transmitted to the rotor is reduced, and thereby the noise generated between the rotor and the cooling fan is reduced. is reduced, and
The flow of outside air introduced from the outside is diffused over a wide area, and the outer ring regulates the airflow, effectively cooling the engine cylinder, generator rotor, and the inside of the generator. The ring has the advantage of suppressing vibration of the fin.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of a forced air-cooled engine to which a cooling fan according to the present invention is applied, and FIG. 2 is a partially cutaway end view of FIG. 1. 1...Engine, 3...Alternator, 4...Rotor, 5...Cooling fan, 5b...Fin.

Claims (1)

[Claims] 1 Forced air cooling in which a cooling fan is installed on the outer end surface of the rotor of the generator, which is installed at the end of the rotating shaft driven by the engine and housed in the storage member, and cools the engine with the wind flow generated as the rotor rotates. In a cooling fan for an engine, the outer diameter of the end face that contacts the end face of the rotor of the fan is formed to be smaller than the outer diameter of the end face of the rotor, and a predetermined interval is provided in the circumferential direction on the periphery of the end face of the fan. None, and a plurality of fins are erected substantially perpendicularly to the end surface, and each of these fins is extended radially outward from the end surface of the rotor from the peripheral edge, and at least the end surface of the rotor is covered with the fins. An outer ring is provided to connect the outer parts on the side opposite to the engine, and an opening is provided in the storage member and the rotor through which the air flow generated from the air outlet of the fan flows. Cooling fan for air-cooled engines.