JPH07269679A - Crank pulley - Google Patents

Abstract

PURPOSE:To reduce noise emitted forward of a crank pulley by providing a layer in which noise insulation boards are laminated with an elastic material held therebetween. CONSTITUTION:Asphalt pitch 2 is filled between arms, and a front face is closed by an iron plate 3, and an iron plate 5 is stuck through a rubber frame 6 on the closed front face, thereby forming an air chamber 7 surrounded by the rubber frame 6 between the iron plate 3 and the iron plate 5. The formed crank pulley is fixed at the tip of a crankshaft 9 projecting forward from a timing gear cover 8 through a pulley set bolt 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crank pulley attached to the tip of a crank shaft of an engine.

[0002]

2. Description of the Related Art As shown in FIG.
A crank pulley P is attached to a tip end portion of a crank shaft 9 protruding from the timing gear cover 8, and a generator, a cooling fan, and the like are belt-driven via the crank pulley P. During operation of the engine, noise is generated from beginning to end from the crank pulley P and the timing gear cover 8 as well as the body of the engine E, and the noise causes a noise between the crank pulley P and the timing gear cover 8. Resonance occurs at these points, and those noises are radiated forward (in the direction in which the crankshaft protrudes). Therefore, conventionally, for example, as shown in FIG. 9a, a rubber member having a vibration damping function in a front space of a crank pulley body 1 in which a rim 1a and a boss 1b are connected at a rear side via a disk-shaped arm 1c. While filling 14
The front surface of the crank pulley body 1 is closed by a sound insulation plate 15 made of an elastic material such as synthetic resin, or as shown in FIG. 9b.
A technique for reducing the noise radiated to the front surface of the crank pulley P by attaching a metal plate 17 wrapped with an elastic material 16 to the front surface except for the central portion of
No. 185455), and as shown in FIG. 10, the sound insulation plate 15 is provided on the front and rear surfaces of the crank pulley body 1.
Elastically supporting the crank pulley P as described above.
To reduce the noise radiated to the front of the vehicle (Actual development 55-
Disclosed in Japanese Patent No. 104733) is known.

[0003]

In the former type shown in FIG. 9a, the sound insulating plate 15 is directly attached to the crank pulley body 1 by the bolts 18, so that the crank pulley body 1
Vibration is directly transmitted to the sound insulation plate 15, and noise is radiated from the sound insulation plate 15 to the front surface, and noise from the timing gear cover arranged behind the crank pulley with the closed surface on the rear side and However, a reduction effect cannot be expected for the resonance sound caused by the noise. In the latter shown in FIGS. 9b and 10, the central portion is opened and the pulley set bolt 10 is exposed, so that the noise generated from the central portion that accounts for most of the noise generated from the crank pulley body 1 is reduced. Is not effective, and if the central part is closed, the attachment / detachment operation cannot be performed. Particularly, in the structure of FIG. 10, the structure for elastically supporting the sound insulating plate is unstable and poor in durability, and cannot be put to practical use as a crank pulley rotating at a high speed.

[0004]

SUMMARY OF THE INVENTION The present invention provides a crank pulley effective not only for reducing the noise generated from the crank pulley itself but also for reducing the noise radiated from the rear. Is a front surface of the crank pulley having a through portion in the front-rear direction between the rim and the boss, and is completely closed by a removable metal plate to form a space opened rearward through the through portion, A sound-insulating layer is provided by filling the space with a sound-absorbing material, and attaching a sound-insulating plate on the front surface of the metal plate with at least the entire periphery being sandwiched with an elastic material. Further, as a specific configuration of the sound insulation layer,
Bolt the metal plate from the front side, form a hole for rotating the bolt head in the sound insulation plate, sandwich an elastic material around the hole, or between the closing surface and the sound insulation plate,
A closed air chamber surrounded by a rubber frame is formed.

[0005]

The noise from the rear is absorbed by the filled sound absorbing material, and the noise generated by the crank pulley and the noise leaking from the sound absorbing material are attenuated by the sound insulating layer formed between the metal plate and the sound insulating plate. , Finally, it is cut with a sound insulation board.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a crank pulley according to the present invention will be described with reference to the drawings. In FIG. 1 in which the constituent members are shown separately, 1 is a crank pulley body, and the crank pulley body 1 includes a rim 1a having a belt groove on the outer periphery,
A boss 1b arranged on the central axis of the rim 1a is connected by cross-shaped arms 1c, 1c ..., And the boss 1b has a shape which is displaced rearward. Further, screw holes 1d, 1d, ... Are formed in the front surface corresponding to the connection portion with the arms 1c, 1c, .. Reference numeral 2 is an aspitch as a sound absorbing material, and this aspitch 2 has an outer shape and a thickness adapted to the inner circumference of the rim 1a so as to match the space shape surrounded by the rim 1a, and a through hole corresponding to the boss 1b at the center. It has a hole 2a, and is punched into a shape having concave portions 2b, 2b, ... Corresponding to the arms 1c, 1c. 3 is an iron plate having the same diameter as the outer circumference of the rim 1a, and bolt insertion holes 3a, 3a ... Are formed at positions corresponding to the screw holes 1d, 1d.
It is tightly fixed to the front surface of the rim 1a through the bolts 4, 4 ...

Reference numeral 5 denotes an iron plate as a sound insulating plate, which has the same diameter as the iron plate 3 and is provided at the positions corresponding to the bolt insertion holes 3d, 3d ...
a ... Is cut out. Reference numeral 6 denotes a rubber frame as an elastic material, which is formed by cutting out a shape in which a ring portion along the entire peripheral edge of the iron plate 5 and a ring portion surrounding each outer periphery of the round window 5a are integrally connected.

Explaining an example of assembling the above-mentioned members, first, the space between the arms 1c and 1c surrounded by the rim 1a of the crank pulley main body 1 is pushed and filled with the aspitch 2, while the iron plate 3 and Rubber frame 6 between the iron plate 5
And the iron plates 3 and 5 and the rubber frame 6 are vulcanized and bonded.
Since the aspitch has elasticity, when it is pushed into the space, it is transformed into the shape of the space and filled without any gap. The front surface of the crank pulley body 1 is provided with an iron plate 3 through the rubber frame 6.
And the iron plate 5 are attached to each other, and the iron plate 3 having a sound insulating layer formed on the front surface (hereinafter referred to as a sound insulating iron plate layer) is brought into close contact with the surface, and is fastened and fixed with bolts 4, 4 ... As a result, the aspitch 2 has the arms 1c, 1c, ... And the iron plate 3
The iron plate 3 and the iron plate 5 are joined together only through the rubber frame 6 because they are sandwiched by and, and the air chamber 7 as a sound insulating layer is formed between the iron plates 3 and 5 of the sound insulating iron plate. (See Figure 2). The thickness of the iron plate 3 and the rubber frame 6 is 1.5, respectively.
mm, the thickness of the iron plate 5 is 1 mm. In the crank pulley P configured in this way, the bolts 4, 4 ... Are removed, the soundproof iron plate is once separated from the pulley body 1, and the front side is opened.
As shown in FIG. 2 showing the mounted state, the timing gear cover 8
The boss 1 is attached to the tip of the crankshaft 9 protruding from the front.
b is fitted and fixed with the pulley set bolt 10, and the removed sound insulating iron plate layer is attached. Reference numeral 11 shown in the drawing is an oil seal.

During operation of the engine, the crankshaft 9
Since vibration is caused by the action of twisting, bending, etc., particularly near the oil seal 11 of the timing gear cover 8 violently vibrates, and noise is also emitted from the crank pulley body 1. Secondary noise is also generated from the space between these noise sources due to the resonance phenomenon. Since the rear of this noise source is blocked by the main body of the engine E, most of the noise is emitted toward the front. The noise and resonance sound generated near the oil seal 11 of the timing gear cover 8 and the rear portion of the crank pulley P are attenuated and absorbed by the sound absorbing material composed of the aspitch 2, and also the noise and resonance sound generated by the crank pulley P and the aspitch 2 are absorbed and absorbed. The noise that could not be cut is reduced in the air chamber of the soundproof iron plate layer and cut by the iron plate, and the radiation sound to the front is drastically reduced.

The noise levels of the engine equipped with the crank pulley of the above-described embodiment and the engine equipped with the crank pulley in which the sound absorbing material and the sound insulating plate are omitted from the crank pulley are compared. The results are shown in Fig. 3. From this result, it can be confirmed that the reduction effect of 2.5 to 3.5 db is exerted over the entire range of the rotation number used. Also on the side, 1.5
A reduction effect of ~ 2db was observed. It was also found that the sound absorption effect is more remarkable as the penetration area in the front-rear direction between the rim and the boss is wider, and in order to enhance the sound insulation effect, it is effective to widen the air chamber.

In the above embodiment, the crank pulley main body has the columnar arms in the cross direction, but the number of columnar arms is not limited to four, and if the number is two or more, the number and The shape can be freely selected. For example, as shown in Figure 4,
A rim 1a having a belt groove on the outer periphery and a boss 1b arranged on the central axis of the rim 1a are connected by a disc-shaped arm 1c, and the arm 1c has through holes 12, 1 for reducing the weight.
In the crank pulley main body 1 in which 2 ... Is formed, the arm 1c can be filled by sandwiching the arm 1c from both the front and back sides with the aspitch 2, 2 as a sound absorbing material. In this case, the protrusion 2 corresponding to the through holes 12, 12, ...
. are provided, and the protrusions 2c, 2c ... Are inserted into the through holes 12, 12 ..
If it is adhered to the asphalt 2, the aspit 2 is securely held. Further, as shown in the same drawing, the shape of the rubber frame can be simplified by using a countersunk bolt to reduce the size of the round window 5a formed in the iron plate 5 or by interposing a set of large and small rubber frames 6. .

The present invention does not matter how the metal plate is attached so long as it can be attached and detached. The metal plate can be tightened with bolts from the rear. As shown in FIG. Bolt insertion hole 1 that penetrates 1a in the front-back direction
If e is provided and a screw hole is formed in the iron plate 3 so that the bolt head is not exposed to the front, it is not necessary to form a hole for exposing the bolt head in the iron plate 5, which is a sound insulating plate, and the air chamber The area of 7 can be expanded.
In the above embodiment, the air chamber 7 is provided between the metal plate 3 and the metal plate 5.
However, as illustrated in FIG. 6, the case where the air chamber is not formed at all by interposing the rubber plate 13 on the entire surface,
As shown in FIG. 4, even when a small hole is provided in the rubber plate 13 to form a large number of independent small air chambers 7, 7 ,.

In the crank pulley of the present invention, the pulley set bolt can be rotated by removing the sound insulating iron plate layer, which is convenient for replacement and maintenance. In the present invention, the sound absorbing material is preferably aspitch considering heat resistance, but it is also possible to use foamed urethane having excellent heat resistance other than aspitch, and a metal plate other than iron is used as the sound insulating plate. Alternatively, the rubber frame or the rubber plate and the metal plate may be bonded with a general adhesive. Although rubber is most suitable as the elastic material, it is conceivable to use a material other than rubber by developing new materials in the future.

[0014]

According to the present invention, the sound insulation and the sound insulation are performed very efficiently by arranging the sound absorption material and the sound insulation material reasonably and by closing the entire front side with the sound insulation iron plate layer. The amount of noise radiation to is reduced dramatically. Further, since the sound insulating iron plate layer with the front surface closed is removable, the crank pulley can be easily removed, and there is no inconvenience in terms of maintenance.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a crank pulley according to the present invention separately shown for each member.

FIG. 2 is an explanatory diagram of how the crank pulley is mounted.

FIG. 3 is a graph showing a comparative example of noise levels.

FIG. 4 is an explanatory diagram of a modification example.

FIG. 5 is an explanatory diagram of a modification example.

FIG. 6 is an explanatory diagram of a modification example.

FIG. 7 is an explanatory diagram of a modification example.

FIG. 8 is an explanatory diagram illustrating the appearance of the engine.

FIG. 9 is an explanatory diagram of a conventional example for both a and b.

FIG. 10 is an explanatory diagram showing another conventional example.

[Explanation of symbols]

1 ... Crank pulley body, 1a .. Rim, 1b .. Boss, 1c .. Arm, 1d .. Screw hole, 1e .. Bolt insertion hole, 2 ... Aspitch, 2a .. Through hole, 2b .. 2c ··· Protrusions ··· Iron plates 3a · · Bolt insertion holes 3b · · Screw holes 4 · · Bolts 5 · · Iron plates 5a
..Round window, 6 ... Rubber frame, 7 ... Air chamber, 8 ... Timing gear cover, 9 ... Crankshaft, 10 ... Pulley set bolt, 11 ... Oil seal, 12 ...・ Rubber plate, 14 ・ ・ Rubber member, 15 ・ ・ Sound insulation plate, 16 ・ ・ Elastic material, 17 ・ ・ Metal plate, 18 ・ ・ Bolt, E ・ ・ Engine, P ・ ・ Crank pulley

Claims (3)

[Claims] 1. A front surface of a crank pulley having a through portion in the front-rear direction between a rim and a boss is entirely covered with a removable metal plate to form a space open rearward through the through portion. A crank pulley having a sound-insulating layer formed between the metal plate and the sound-insulating plate by filling the space with a sound-absorbing material, sandwiching at least the entire periphery of the front surface of the metal plate with an elastic material, and adhering the sound-insulating plate. . 2. The sound insulation layer is formed by bolting a metal plate from the front side, forming a hole for exposing the bolt head in the sound insulation plate, and surrounding the hole between the metal plate and the sound insulation plate. The crank pulley according to claim 1, further comprising an elastic material sandwiched between the crank pulley and the crank pulley. 3. The crank pulley according to claim 1, wherein in the sound insulation layer, an air chamber having a closed structure surrounded by a rubber frame is formed between the closed surface and the sound insulation plate.