JP3079868B2 - Crank pulley - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crank pulley used for an internal combustion engine.

[0002]

2. Description of the Related Art A general crank pulley is disclosed in
As described in Japanese Patent Application Publication No. 1157956, a hub portion, a mounting boss portion extending from the center portion of the hub portion to the crankshaft side, and extending from a peripheral portion of the hub portion to the opposite side of the crankshaft. It is formed from a cylindrical pulley part, and a driving belt is hung on the outer periphery of the pulley part. This crank pulley has a shape in which a central portion that is considered unnecessary is omitted in a concave shape in order to reduce the weight.

In recent years, it has become common to provide a vehicle with a power steering, an air conditioner, and the like. In such a case, it is necessary to attach a pulley for driving the power steering to a crank pulley. Are arranged at equal angular intervals on the hub portion of the crank pulley.

[0004]

In a crankshaft to which such a crank pulley is attached, a vertical bending vibration occurs at the time of an explosion in each cylinder of the internal combustion engine. It is displaced and then displaced downward by reaction. This vertical movement gives a bending moment in the front-rear direction to the upper half and the lower half of the crank pulley at the rotation position at this time.

Accordingly, the upper half and the lower half of the crank pulley vibrate back and forth with the upper and lower tangents of the boss perpendicular to the cylinder axis as nodes, and this vibration noise is generated by the hub and the pulley. In the recessed space, which results in relatively loud noise.

Accordingly, it is an object of the present invention to provide a crank pulley for an internal combustion engine which can significantly reduce such noise without increasing the cost.

[0007]

A crank pulley according to the present invention comprises a hub, a mounting boss extending from a central portion of the hub toward the crankshaft, and an anti-crank from a peripheral portion of the hub. A substantially cylindrical pulley portion extending to the shaft side, and a plurality of pedestals arranged at equal angular intervals on the hub portion for attaching other pulleys and the like, when a predetermined cylinder of the internal combustion engine explodes. Wherein at least one of the pedestals is located on a tangent to at least one of the bosses perpendicular to the axis of the cylinder.

[0008]

The above-mentioned crank pulley is provided at equal angular intervals on a hub portion for mounting another pulley on at least one tangent of a boss portion perpendicular to the axis of the cylinder when the predetermined cylinder of the internal combustion engine explodes. Since at least one of the plurality of pedestals arranged at the position is located, at the time of the explosion of this cylinder, at least one of the two tangents of the boss portion that serves as a node of the vibration of the crank pulley, The second moment of area can be considerably increased.

[0009]

FIG. 1 is a front view showing a first embodiment of a crank pulley of an internal combustion engine according to the present invention, and FIG.
It is a P sectional view. This embodiment shows a case where the internal combustion engine is an in-line four-cylinder engine. In these figures, reference numeral 1 denotes a circular hub portion, and reference numeral 2 denotes a boss portion extending from a central portion thereof mainly to the crankshaft side. At the center of the boss portion 2, a shaft hole 2b having a keyway 2a and fitted to a crankshaft is formed. A substantially cylindrical pulley portion 3 on which a drive belt is hung extends around the hub portion 1 on the side opposite to the crankshaft. A drive belt is fitted on the outer peripheral portion of the pulley portion 3 to prevent the belt from slipping in the width direction.
The V-shaped groove 3a is formed, and a rubber damper member 3b that makes it difficult to transmit engine vibrations and the like to the drive belt is disposed inside the V-shaped groove 3a.

The hub 1 is provided with four pedestals 4a, 4b, 4c, 4d each having a threaded hole for mounting other pulleys for driving a power steering, an air conditioner, and the like. They are arranged at angular intervals. 5 is a pedestal 4a, 4b, 4c, 4d and a pulley 3
And a rib for connecting.

The positions of the key grooves of the crankshaft and the crank pulley determine the rotational positional relationship between the two. In this embodiment, the position of the key groove 2a of the crank pulley in FIG. It corresponds to the crank angle at the top dead center, and the axis A passing through the center and the center of the shaft hole 2b is parallel to the axis of each cylinder. The pedestals 4a, 4b, 4c, and 4d are arranged at an angle of 45 degrees with respect to the axis A. In particular, the pedestals 4a, 4b
Is located on the tangent line C above the boss portion 2 of the crank pulley perpendicular to the axis A, that is, the axis of each cylinder, and the pedestals 4c and 4d are located on the lower side of the similar boss portion 2. It is located on tangent D.

When a bending vibration occurs in the crankshaft due to the explosion of each cylinder, the crank pulley side end moves up and down, and this gives a bending moment in the longitudinal direction to the crank pulley. Due to this bending moment, the upper half of the crank pulley vibrates back and forth at this rotational position with the tangent C on the upper side of the boss portion 2 perpendicular to the axis of the exploding cylinder as a node, and the lower half has the same structure. Vibration is similarly made with the tangent line D below the boss 2 as a node. In the prior art, such consideration is not made for the arrangement of the pedestal, for example,
When a vibration node is formed between the pedestal and the boss, as shown in FIG. 2, the second moment of area of the crank pulley in the front-rear direction at this portion is considerably small, and the amplitude of the vibration becomes large. Vibration noise is amplified in the concave space formed by the hub portion 1 and the pulley portion 3, and very loud noise is generated. In this embodiment, since the two pedestals are arranged on the tangents C and D at the time of the explosion of the specific cylinder, the second moment of area of the crank pulley in this direction in the front-rear direction at this position becomes very large. The amplitudes of the vibrations in the upper and lower halves described above can be made very small, thereby significantly reducing the noise generated.

This embodiment shows a case where the internal combustion engine is an in-line four-cylinder engine, as described above, whereby explosions of cylinders other than the specified cylinder are executed at every 180 ° crank angle. Therefore, in the case of any cylinder explosion, the two tangents C,
Since two pedestals are always located on D, noise due to vibration of the crank pulley when all cylinders explode can be considerably reduced.

FIG. 3 is a front view showing a second embodiment of the crank pulley of the internal combustion engine according to the present invention. Only the differences from the first embodiment shown in FIGS. 1 and 2 will be described below. In the crank pulley of this embodiment, three pedestals 4a ', 4
b ′ and 4c ′ are arranged at equal angular intervals of 120 °. In particular, the pedestal 4a 'is located on the tangent line C above the boss 2 perpendicular to the axis of this cylinder when the specific cylinder explodes.

The crank pulley having such a structure has an 18
When used in an in-line four-cylinder internal combustion engine in which an explosion is performed at every 0 ° crank angle, the pedestal 4a 'is located on the tangent to the upper or lower boss portion 3 when each cylinder explodes. And the second moment of area at that portion becomes large, suppressing the vibration of the upper half or the lower half of the crank pulley, thereby reducing the noise. In this case, if one pedestal is at the above-mentioned position, it is obvious that the number of other pedestals arranged at equal angular intervals with respect to this can be arbitrarily selected. This crank pulley is also effective for an in-line six-cylinder internal combustion engine in which an explosion is performed every 120 ° crank angle. In this case,
At the time of the explosion of the specific cylinder, the pedestal 4a ′ suppresses the vibration of the upper half of the crank pulley.
Similarly, in the case of any cylinder explosion, one pedestal always locates the vibration of the upper half of the crank pulley at the node,
This vibration can be suppressed to reduce noise at this time.

In the second embodiment, the axis A and the pedestal 4a '
Can be arbitrarily selected, and in particular, is set to 30 °, and the three pedestals 4a ′, 4
By providing three new pedestals that are symmetrical with respect to the axis A with respect to b ′, 4c ′ and the axis A, when the internal combustion engine is an in-line six-cylinder engine, when each cylinder explodes, a boss portion serving as a node of vibration of the crank pulley Two pedestals are always located on the two tangents, and the noise generated at this time can be considerably reduced.

FIG. 4 is a front view showing a third embodiment of the crank pulley of the internal combustion engine according to the present invention. Only the differences from the first embodiment shown in FIGS. 1 and 2 will be described below. Two pedestals 4a, 4d, 4b, and 4c adjacent to each other in the direction of the axis A among the pedestals 4a, 4b, 4c, and 4d in the present embodiment.
Are connected to each other by a rib 6. Also each pedestal 4
The ribs 5 ′ connecting the a, 4 b, 4 c, 4 d and the pulley section 3 extend in the same direction as the rib 6.
With this structure, the above-described vibration of the crank pulley when the internal combustion engine is an in-line four-cylinder engine is suppressed in the same manner as in the first embodiment.
Can be suppressed.

FIG. 5 shows a fourth embodiment in which a cover is provided on the crank pulley of the first embodiment, and FIG. 6 is a sectional view taken along line QQ. This cover is intended to cover the concave space formed by the hub portion 1 and the rib portion 3 and to prevent the vibration noise of the crank pulley amplified in this space. As shown in these figures, the crank pulley is connected to the crankshaft 1 by bolts 7.
0 end. The bolt 7 has a head 7a protruding from the end face of the pulley portion 3 of the crank pulley, and a rubber cover 8 penetrated by the head 7a is formed at the edge of the pulley portion 3. It fits into the chip. As shown in FIG. 5, the cover 8 is formed with cuts such that the pedestals 4a, 4b, 4c, 4d and the ribs 5 are exposed.

The head 7a of the bolt 7 has a hexagonal cross-section at the tip, so that the bolt 7 can be tightened with a spanner or the like. The portion in contact with the cover 8 has a circular cross section having a diameter equal to or longer than the diagonal line of the above-described hexagonal cross section, and the through hole 8a of the cover 8 has a circular shape having the same diameter.

As described above, by protruding the head 7a of the bolt 7 from the cover 8, during inspection of the internal combustion engine,
Without removing the cover 8, the piston position of each cylinder can be estimated from the rotational position of the head 7a.
General bolts have a hexagonal cross-section over the entire head, so if you form a through hole in the cover to match it,
There is no guarantee that the notch in the cover will match the position of the pedestal and ribs after bolting, so that the through hole in the cover must be circular with a diameter at least as long as the diagonal of the hexagonal cross section of the bolt head. In addition, a gap is formed between the bolt head and the through hole, and there is a problem that the soundproofing effect of the cover is reduced. However, this problem can be solved by forming the bolt 7 and the cover 8 as in the present embodiment. Further, as shown in the figure, a ring-shaped notch is provided at a portion of the head 7a of the bolt 7 which is in contact with the cover 8 so that the through hole 8a of the cover 8 fits into this notch, thereby providing a more soundproof effect. Is improved.

[0021]

As described above, according to the crank pulley of the present invention, when a predetermined cylinder of an internal combustion engine explodes, another pulley or the like is placed on at least one tangent to a boss portion perpendicular to the axis of the cylinder. Since at least one of the plurality of pedestals arranged at equal angular intervals is located on the hub portion for mounting, at the time of this cylinder explosion, at least two tangents of the boss portion which becomes a node of vibration of the crank pulley. On the one hand, the second moment of area of the crank pulley in the front-rear direction can be significantly increased, the amplitude of this vibration is reduced, and the noise generated thereby can be significantly reduced. The present invention can reduce the vibration without losing the function of the pedestal itself for attaching another pulley or the like by specifying the position of the pedestal that is generally provided, so that a new vibration reducing member is provided. There is no need to provide

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of a crank pulley according to the present invention.

FIG. 2 is a sectional view taken along line PP of FIG. 1;

FIG. 3 is a front view showing a second embodiment of the crank pulley according to the present invention.

FIG. 4 is a front view showing a third embodiment of the crank pulley according to the present invention.

FIG. 5 is a front view showing a fourth embodiment of the crank pulley according to the present invention.

FIG. 6 is a sectional view taken along line QQ of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hub part 2 ... Boss part 3 ... Pulley part 4a, 4b, 4c, 4d, 4a ', 4b', 4c '... Pedestal 6 ... Rib 7 ... Bolt 8 ... Cover 10 ... Crankshaft

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 61-11756 (JP, U) Japanese Utility Model Showa 58-18031 (JP, U) Japanese Utility Model Showa 60-7359 (JP, U) Japanese Utility Model Hei 1 163237 (JP, U) Hira 2-62137 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16F 15/26 F16H 55/36

Claims (1)

(57) [Claims] 1. A hub portion, a mounting boss portion extending from a center portion of the hub portion to the crankshaft side, and a substantially cylindrical pulley extending from a peripheral portion of the hub portion to a side opposite to the crankshaft. Part, a plurality of pedestals arranged at equal angular intervals on the hub part for attaching other pulleys and the like,
A crank pulley, wherein when a predetermined cylinder of the internal combustion engine explodes, at least one of the pedestals is located on a tangent to at least one of the bosses perpendicular to the axis of the cylinder.