JPH10252867A - Crank pulley with noise insulating cover - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crank pulley with noise insulating cover, which can be stably installed without using an installation bolt and in which a noise insulating cover to be easily connected and disconnected is installed. SOLUTION: A crank pulley 1 is fixed to a crank shaft 7 by a fixing bolt 6, and while a noise insulating cover 2 is installed so as to cover the fixed bolt 6 part. The noise insulating cover 2 is provided with a male thread 25 over the outer peripheral edge thereof, and on the other hand, the crank pulley 1 is provided with a female thread 15 over the whole circumference of the inner peripheral edge thereof. The peripheral edge of the noise insulating cover 2 is screwed with the crank pulley 3. Screwing direction of the male thread 25 and the female thread 15 are desirably provided so that the fastening direction thereof is opposite to the rotating direction of the crank pulley 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulation cover for insulating noise generated from a crank pulley portion of an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, there has been an increasing need to reduce noise during operation of internal combustion engines used for passenger cars, industrial vehicles and the like. Noise in an internal combustion engine comes from various parts. In particular, the noise generated from the fixing bolt portion that fixes the crank pulley to the crankshaft is very loud. Therefore, it has been proposed to mount a sound insulation cover on the end face of the crank pulley in order to isolate the sound generated from the fixing bolt.

For example, as shown in FIGS. 6 and 8, the conventional sound insulating cover 8 has a structure in which ring-shaped rubber sheets 82 and 83 are attached to the front and back surfaces of an outer peripheral portion of a vibration-isolating steel plate 81, respectively. ing. As shown in FIG. 6, the rubber sheets 82 and 83 are provided with four bolt holes 84 in which the mounting bolts 88 are inserted.

On the other hand, as shown in FIG. 7, the crank pulley 9 to which the sound insulating cover 8 is mounted has a mounting screw hole 94 at a position corresponding to the bolt hole 84. When mounting the sound insulation cover 8 on the crank pulley 9, as shown in FIG.
Is attached to the front surface 91 of the crank pulley 9, the mounting bolt 88 is mounted on the mounting screw hole 94 via the bolt hole 84, and the bolt is tightened.

Thus, the fixing bolt 6 for fixing the crank pulley 9 to the crankshaft 7 is covered by the sound insulating cover 8. The crank pulley 9 equipped with the sound insulating cover 8 can significantly reduce the noise during operation of the internal combustion engine as compared with a state in which the sound insulating cover 8 is not installed.

[0006]

However, the conventional crank pulley 9 with a sound insulating cover has the following problems. That is, when the sound insulation cover 8 is mounted on the crank pulley 9 using the mounting bolts 88, it is necessary to use at least four mounting bolts 88 in order to obtain a stable mounting state. This not only leads to an increase in the number of parts, but also deteriorates serviceability during maintenance.

More specifically, when it is necessary to perform cranking (operation for manually rotating the crankshaft), for example, all four bolts are removed and the sound insulating cover 8 is removed.
Need to be removed. For this reason, the serviceability is greatly deteriorated as compared with the crank pulley 9 without the sound insulation cover 8. Therefore, a sound insulation cover to be attached to the crank pulley 9 is required to be easily removable.

Further, the sound insulation cover 8 with the mounting bolt 88 is provided.
Are fixed via rubber sheets 82 and 83, respectively, so that the mounting bolt 88 and the vibration isolating steel plate 81 do not directly contact with each other, and the vibration isolating steel plate 81 and the crank pulley 9 do not directly contact each other. This is to prevent the transmission of vibrations by preventing so-called metal touch between metals.

Although the interposition of the rubber sheets 82 and 83 is effective in preventing the above-mentioned vibration transmission, it has a problem that the mounting bolt 88 is loosened. That is, the rubber sheets 82 and 83 oppose the pressing force of the mounting bolt 88 by their own elastic force, and maintain the tightened state of the mounting bolt 88. However, the rubber sheet 8
In Nos. 2 and 83, the elastic force is reduced by the action of the compressive stress for a long period of time, so that a state is obtained in which the rubber is soaked.
Therefore, the pressing force of the mounting bolt 88 is reduced, and the mounting bolt 88 is gradually loosened due to rotation of the crank pulley 9 or the like.

The present invention has been made in view of such a conventional problem, and has a sound insulation cover which can be stably mounted without using a mounting bolt and which can be easily attached and detached.
An object of the present invention is to provide a crank pulley with a sound insulation cover.

[0011]

According to a first aspect of the present invention, there is provided a crank pulley which is fixed to a crankshaft by a fixing bolt and has a sound insulating cover attached so as to cover the fixing bolt portion. An external thread is provided on the entire circumference, while a female thread is provided on the inner circumference of the crank pulley, and the outer edge of the sound insulating cover is screwed to the crank pulley. In a crank pulley with a sound insulation cover.

The most remarkable point in the present invention is that the sound insulation cover is provided with the male thread and the crank pulley is provided with the female thread, so that the sound insulation cover itself can be used without using a mounting bolt or the like. It is screwed to the crank pulley.

The sound insulation cover is obtained by, for example, shaping a steel material, an aluminum material, and other vibration-proof materials excellent in a vibration-proof function into a disk shape. Then, the external thread is threaded on the outer peripheral edge as described above. Further, a projection or a concave portion for rotating the sound insulating cover is provided on the front side surface. For example, it is a concave portion for a tool described later. The internal thread of the crank pulley is provided corresponding to the external thread of the sound insulation cover.

Next, the operation of the present invention will be described. As described above, the crank pulley with a sound insulation cover of the present invention
The entire outer periphery of the sound insulation cover is screwed into the crank pulley. Therefore, the engagement between the sound insulation cover and the crank pulley can be made stronger than in a method in which several points are pressed and fixed with bolts. Further, it is not necessary to use a plurality of mounting bolts as in the related art. Therefore, not only the number of parts can be reduced, but also the problem caused by the loosening of the mounting bolt as in the related art can be surely avoided.

The sound insulation cover can be easily attached to and detached from the crank pulley by rotating the sound insulation cover itself. Therefore, when performing, for example, cranking during maintenance, the sound insulation cover can be quickly removed, and good serviceability can be obtained.

Therefore, the crank pulley with the sound insulating cover of the present invention can not only reduce the noise as the original object, but also maintain a stable mounting state and obtain excellent detachability. it can.

Next, as in the second aspect of the present invention, it is preferable that the threading direction of the male thread and the female thread is provided such that the tightening direction is opposite to the rotation direction of the crank pulley. . As a result, due to the inertial force accompanying the start of rotation of the crank pulley when the internal combustion engine is started,
The sound insulation cover is urged in the tightening direction. Therefore, the mounting stability of the sound insulating cover to the crank pulley can be further improved.

Preferably, a tool recess for inserting a rotary tool is provided in the center of the sound insulation cover. Thus, the sound insulating cover can be easily rotated using the rotary tool, and the detachability of the sound insulating cover from the crank pulley can be further improved.

Further, as in the invention of claim 4, the concave portion for the tool can be formed in a polygonal shape for inserting a polygonal wrench. For example, when a hexagon wrench is used, a hexagonal concave portion can be formed.

Further, it is preferable that the crank pulley is provided with a through hole penetrating a back surface thereof. In this case, it is also possible to reduce noise generated between the crank pulley and the housing located at a predetermined distance from the rear side of the crank pulley. In other words, the front surface of the crank pulley to which the sound insulation cover is attached is a closed space. By providing the through hole in the back wall of the closed space, a so-called Helmholtz resonator is formed, and a very excellent sound absorbing effect is exhibited.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A crank pulley with a sound insulating cover according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the crank pulley 1 with a sound insulating cover according to the present embodiment is a crank pulley that is fixed to a crankshaft 7 by a fixing bolt 6 and has a sound insulating cover 2 attached to cover the fixing bolt 6.

As shown in FIG. 2, the sound insulation cover 2 is made of a disc-shaped steel material, and has a male thread 2 around the entire outer peripheral edge thereof.
5 is provided. On the other hand, as shown in FIGS. 1 and 3, the crank pulley 1 has a bowl shape with the fixing bolt 6 mounting side at the bottom.
Is provided. The outer peripheral edge of the sound insulation cover 2 is screwed to the crank pulley 1.

The external thread 25 of the sound insulating cover 2 and the internal thread 15 of the crank pulley 1 are threaded in such a manner that the tightening direction is opposite to the rotation direction of the crank pulley 1. A hexagonal tool recess 22 for inserting a hexagon wrench is provided in the center of the sound insulation cover 2. Reference numeral 19 in the crank pulley 1 denotes a belt groove for fitting the belt 5.

Next, the operation of this embodiment will be described.
The crank pulley 1 with a sound insulating cover of this example is formed by screwing the entire outer periphery of the sound insulating cover 2 to the crank pulley 1. Therefore, attachment and detachment of the sound insulation cover 2 can be performed very easily.

That is, when mounting the sound insulating cover 2 on the crank pulley 1, the outer peripheral edge of the sound insulating cover 2 is brought into contact with the inner peripheral edge of the crank pulley 1, as shown in FIG. Next, a hexagon wrench is inserted into the tool concave portion 22 of the sound insulation cover 2 and is turned. As a result, the external thread 25 on the outer peripheral edge of the sound insulating cover 2 and the internal thread 15 on the inner peripheral edge of the crank pulley 1 are screwed together, and the sound insulating cover 2 can be easily mounted on the crank pulley 1. On the other hand, when removing the sound insulation cover 2, it can be easily performed by inserting a hexagonal wrench into the tool recess 22 and rotating it in the opposite direction. Therefore, serviceability during maintenance is very good.

The mounting of the sound insulating cover 2 on the crank pulley 1 in this embodiment is performed by engaging the entire outer peripheral surface of the sound insulating cover 2 with the entire inner peripheral surface of the crank pulley 1 as described above. For this reason, a significantly stable coupling state can be obtained as compared with a case where the mounting state is maintained only at four points, for example, as in the case of the conventional mounting bolt.

Further, the tightening directions of the threads 15, 25 of the crank pulley 1 and the sound insulating cover 2 are provided so as to be opposite to the rotation direction of the crank pulley 1. Therefore, due to acceleration during operation of the internal combustion engine, inertial force acts on the sound insulating cover 2 in a direction in which the sound insulating cover 2 is fastened to the crank pulley 1. As a result, the connection between the sound insulating cover 2 and the crank pulley 1 is always firmly maintained.

Therefore, the crank pulley 1 with the sound insulating cover of this embodiment can keep the sound insulating function of the sound insulating cover 2 stable even during the operation of the internal combustion engine. And
There is no need to use a plurality of mounting bolts as in the related art. Therefore, not only the number of parts can be reduced, but also the problem caused by the loosening of the mounting bolt as in the related art can be surely avoided.

Embodiment 2 In this embodiment, as shown in FIGS. 4 and 5, a through hole 17 is provided in the rear wall 16 of the crank pulley 1 of Embodiment 1. Further, the crank pulley 1 of the present embodiment is arranged with a space S of 2 mm between the crank pulley 1 and the housing 3. Other configurations are the same as those of the first embodiment.

The diameter D of the through hole 17 is 2 mm and the length L
(Thickness of the back wall 16) is 10 mm. The space 1 surrounded by the crank pulley 1 and the sound insulating cover 2
The volume V of 9 is 150 mm ³ . Therefore, the through-hole 17 forms a so-called Helmholtz resonator due to the above dimensional relationship. Thereby, a new noise reduction effect is exhibited.

That is, when the crank pulley 1 and the housing 3 are disposed with a gap of about 2 mm, a large noise is usually generated from the gap. On the other hand, in this embodiment, the through hole 17 is provided in the crank pulley 1. Therefore, a so-called Helmholtz resonator exhibits a sound absorbing effect, and noise from the gap is greatly reduced.

Therefore, according to the present embodiment, the sound insulating cover 2
In addition to the reduction in noise from the fixing bolt 6, the noise generated between the crank pulley and the housing can be reduced. In addition, the same effects as those of the first embodiment can be obtained.

[0033]

As described above, according to the present invention, it is possible to provide a crank pulley with a sound insulating cover, which can be stably mounted without using a mounting bolt and has a sound insulating cover which is easily detachable. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of a crank pulley with a sound insulation cover according to a first embodiment.

FIG. 2 is a front view of a crank pulley with a sound insulation cover according to the first embodiment.

FIGS. 3A and 3B are perspective views of (a) a sound insulation cover and (b) a crank pulley according to the first embodiment.

FIG. 4 is a sectional view of a crank pulley with a sound insulation cover according to a second embodiment (as viewed from the direction of arrows BB in FIG. 5).

FIG. 5 is a front view of a crank pulley with a sound insulation cover according to a second embodiment.

FIG. 6 is a front view of a sound insulation cover in a conventional example.

FIG. 7 is a front view of a crank pulley in a conventional example.

FIG. 8 is a cross-sectional view of a conventional crank pulley with a sound insulation cover (viewed along the line AA in FIG. 8).

[Explanation of symbols]

 1. . . 14. crank pulley, . . Internal thread, 2. . . Sound insulation cover, 25. . . Male thread, 6. . . Fixing bolt, 7. . . Crankshaft,

Claims (5)

[Claims] 1. A crank pulley which is fixed to a crankshaft by a fixing bolt and has a sound insulating cover attached so as to cover the fixing bolt portion, wherein the sound insulating cover is provided with a male thread over the entire outer peripheral edge thereof. On the other hand, the crank pulley is provided with a female thread on the entire inner peripheral edge thereof, and the outer peripheral edge of the sound insulating cover is screwed to the crank pulley. 2. The sound-insulating cover according to claim 1, wherein a thread cutting direction of the male thread and the female thread is provided such that a tightening direction thereof is opposite to a rotation direction of the crank pulley. Crank pulley. 3. The crank pulley with a sound insulating cover according to claim 1, wherein a tool recess for inserting a rotary tool is provided at a center of the sound insulating cover. 4. The method according to claim 3, wherein the recess for the tool comprises:
A crank pulley with a sound-insulating cover, wherein the crank pulley has a polygonal shape for inserting a polygonal wrench. 5. The method according to claim 1, wherein:
A crank pulley with a sound insulating cover, wherein the crank pulley is provided with a through hole penetrating a back surface.