JPH05306632A - Timing belt cover of engine - Google Patents

Abstract

PURPOSE:To reduce an air volume in a space part so as to reduce resonance vibration for preventing the peak of noise by forming the space part with respective outside and inside covers for enclosing a timing belt, and also constituting the space part to be capable of being reduced in its volume. CONSTITUTION:An engine 2 is provided with a timing belt 16 for transmitting driving force from a crank shaft 8 to a cam shaft 10. The timing belt 16 is enclosed with a timing belt cover 18 consisting of an outside cover 20 and an inside cover 22. In this case, an space part 24 is formed inside by means of the outside cover 20 and the inside cover 22. A space reducing means 28 for reducing the space part 24 is arranged in order to reduce noise of the timing belt 16. The space reducing means 28 is formed by a box shaped member 30 arranged between a crank shaft pulley 12 and a cam shaft pulley 14 for example, inside the space part 24. It is thus possible to reduce resonance vibration by reducing the air volume in the space part 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine timing belt cover, and more particularly to an engine including an outside cover and an inside cover while surrounding a timing belt for transmitting a driving force from an engine crankshaft to a camshaft. Timing belt cover.

[0002]

2. Description of the Related Art In a vehicle engine, a driving force from a crankshaft is transmitted to a camshaft by a timing belt so that the camshaft is rotated in synchronization with the crankshaft. It is provided so that it is transmitted to the accessory shaft by the accessory belt and rotates the accessory shaft in conjunction with the crankshaft.

In order to protect these timing belts and auxiliary equipment belts from foreign substances such as water, oil, dust, stones, etc., and to prevent danger and noise, the engine is equipped with a timing belt cover and auxiliary equipment belt cover. It is installed.

Particularly, as the timing belt cover,
For example, there is one disclosed in Japanese Utility Model Laid-Open No. 63-150037. The timing belt cover of the internal combustion engine disclosed in this publication is provided with a communication passage communicating with a plurality of parts inside the timing belt cover outside the timing belt cover, and the communication passage of the communication passage is provided to cause air column resonance at a predetermined frequency. The length is selected.

There is also one disclosed in Japanese Utility Model Laid-Open No. 3-49335. The engine timing belt cover disclosed in this publication is one in which a recess is provided in the timing belt cover and a rib is formed in this recess.

[0006]

By the way, in the conventional engine timing belt cover, the engine 10
2 has a cylinder head 104 and a cylinder block 106, as shown in FIG.
One end of the crankshaft 108 is arranged to project from the crankshaft 108, and one end of the camshaft 110 is arranged to project from the cylinder head 104.

Further, in the normal engine 102, as shown in FIGS. 9 to 11, a cam shaft pulley 114 is mounted on one cam shaft 110, and a crank shaft pulley mounted on one end of the crank shaft 108. 112 and cam shaft pulley 11
4 is wound by a timing belt 116 to connect the crank shaft 108 and the cam shaft 110.

The timing belt 116 is surrounded by a timing belt cover 118. The timing belt cover 118 comprises an outside outside cover 120 and an inside cover 122 on the engine 102 side. At this time, the outside cover 120 and the inside cover 122 form a space 124 inside.

The reference numeral 126 designates a space between the outside cover 120 and the inside cover 122 and the engine 1.
02 and the inside cover 122 are seal rubbers.

Further, in a DOHC type engine, for example, as shown in FIG. 12, two camshafts (not shown) have two camshafts.
The cam shaft pulleys 214-1 and 214-2 are mounted,
A crankshaft pulley (not shown) attached to one end of a crankshaft (not shown) and camshaft pulleys 214-1, 214-2
Are wound by a timing belt 216 to connect the crankshaft 208 and the camshaft.

The timing belt cover 218 surrounding the timing belt 216 comprises an outside cover 220 on the outside and an inside cover 222 on the engine 202 side. At this time, a space is formed inside by the outside cover 220 and the inside cover 222.

Reference numeral 226 is a seal rubber provided between the outside cover 220 and the inside cover 222 and between the engine and the inside cover 222.

However, a toothed belt is usually used as the timing belt, and in the toothed belt, a biting sound is generated when the teeth of the belt and the pulley bite.

As a result, the air in the space portion of the timing belt cover causes resonance vibration, and as shown in FIG. 13, a loud noise is generated due to the peak frequency, which is disadvantageous in practical use. There is.

Further, the timing belt cover includes
As shown in FIG. 14, there is a timing belt cover 318 that surrounds only the portion through which the timing belt 316 passes, in addition to the one that surrounds the entire drive portion by the timing belt as described above.

Since the timing belt cover 318 having such a shape has a hollowed-out shape, the radiated sound from the engine body side such as the cylinder block is directly transmitted from the hollowed-out portion to reduce noise. It has inconvenience.

[0017]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides a timing belt for transmitting the driving force from the crankshaft of the engine to the camshaft,
In a timing belt cover for an engine, which comprises an outside cover and an inside cover that surround the timing belt, a space is formed inside by the outside cover and the inside cover, and a space is formed to reduce noise of the timing belt. It is characterized in that a space reducing means for reducing the above is provided.

[0018]

With the above-described invention, the space reducing means reduces the space formed inside the outside cover and the inside cover, thereby reducing the noise of the timing belt.

[0019]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show a first embodiment of the present invention. 1 and 2, 2 is an engine, 4
Is a cylinder head, 6 is a cylinder block, 8 is a crank shaft, and 10 is a cam shaft.

As shown in FIG. 1, the engine 2 has a cylinder head 4 and a cylinder block 6. The engine 2 is arranged so that one end of a crankshaft 8 projects from the cylinder block 6 and the cylinder head 4 extends from the cylinder head 4. One end of the cam shaft 10 is arranged so as to project.

In the engine 2, as shown in FIGS. 1 and 2, a crankshaft pulley 12 is attached to one end of the crankshaft 8 and a camshaft pulley 14 is attached to one end of one camshaft 10. It is installed. The crankshaft pulley 12 and the camshaft pulley 14 are wound around a timing belt 16, and the timing belt 16 connects the crankshaft 8 and the camshaft 10.

Further, the timing belt 16 is surrounded by a timing belt cover 18, and the timing belt cover 18 comprises an outside cover 20 on the outside and an inside cover 22 on the engine 2 side. At this time, a space 24 is formed inside by the outside cover 20 and the inside cover 22.

Reference numeral 26 is a seal rubber provided between the outside cover 20 and the inside cover 22 and between the engine 2 and the inside cover 22.

A space reducing means 28 for reducing the space 24 is provided to reduce the noise of the timing belt 16.

More specifically, the space reducing means 28 reduces the volume of air in the space portion 24 to reduce resonance vibration, and increases the transmission of radiated sound from the cylinder block 6 side without increasing noise. This is to prevent the peak of.

As shown in FIGS. 1 and 2, the space reducing means 28 has a space portion 24 formed by the outside cover 20 and the inside cover 22.
The box-shaped member 30 is provided between the crankshaft pulley 12 and the camshaft pulley 14.

The box-shaped member 30 has an outside cover 20 and an inside cover 22 depending on the design situation.
It is formed integrally with or separately from.

Further, the box-shaped member 30 is composed of a box member having a hollow inside, or a Helmholtz type resonator 32 having a communication hole portion (not shown) which communicates with the space portion 24, for example.

Next, the operation will be described.

When the engine 2 is driven, the crank shaft 8 rotates, and the crank shaft pulley 12 attached to one end of the crank shaft 8 rotates.

The driving force of the crankshaft 8 is transmitted from the crankshaft pulley 12 to the camshaft pulley 14 via the timing belt 16 to drive the camshaft 10 to rotate. Further, the rotationally driven cam shaft 10 drives an intake / exhaust valve (not shown) to open / close via a valve mechanism (not shown).

As a result, the space 24 is formed into the box-shaped member 3
Since it is reduced by 0, the resonance vibration can be reduced to eliminate the peak frequency, and the noise of the timing belt can be reduced without increasing the transmission of the radiated sound from the engine body side, which is practically advantageous. Is.

The space reducing means 28 is provided in the box-shaped member 3
By configuring with 0, the configuration is simple, the manufacturing is easy, the cost can be reduced, and it is economically advantageous.

Further, if the box-shaped member 30 is formed as a separate body, a separate box-shaped member 3 is attached to a ready-made timing belt cover.
It is also possible to reduce the space by arranging 0, which can increase versatility.

Furthermore, if the Helmholtz type resonator 32 is used, an effective silencing effect can be obtained depending on the characteristics of the resonator.

4 and 5 show a second embodiment of the present invention. The parts having the same functions as those in the first embodiment will be described with the same reference numerals.

The feature of the second embodiment is that in the first embodiment, the box-like member 30 is provided as the space reducing means 28, but the recess 40 is formed in the outside cover 20, The space 24 is formed by the recess 40.
The point is that the space reducing means 42 for reducing

That is, as shown in FIGS. 4 and 5, by forming the recess 40 between the crankshaft pulley 12 and the camshaft pulley 14 of the outside cover 20, the inner portion of the recess 40 is located inside the space 24. In addition to projecting, the inside cover 22 has a flat shape as in the first embodiment, and the recess 40 reduces the space 24.

Then, as in the case of the first embodiment described above, the space portion 24 is reduced by the concave portion 40, the resonance vibration can be reduced to eliminate the peak frequency, and the engine body side can be reduced. The noise of the timing belt can be reduced without increasing the transmission of the radiated sound, which is practically advantageous.

Further, since the space reducing means 42 is constituted by the concave portion 40 formed in the outside cover 20, the structure is simple, the manufacturing is easy, the cost can be reduced, and it is economically advantageous. Is.

6 and 7 show a third embodiment of the present invention.

Contrary to the second embodiment, the feature of the third embodiment is that the inside cover 2 is
The convex portion 50 protruding to the space portion 24 is formed in the second portion 2, and the space reducing means 52 is configured by the convex portion 50.

That is, as shown in FIGS. 6 and 7, the outside cover 20 has a flat shape, and a convex portion projecting into the space 24 between the crankshaft pulley 12 and the camshaft pulley 14 of the inside cover 22. Form 50.

Then, as in the first and second embodiments, the space portion 24 is reduced by the convex portion 50, and the resonance vibration can be reduced to eliminate the peak frequency. The noise of the timing belt can be reduced without increasing the transmission of the radiated sound from the engine body side, which is practically advantageous.

Further, since the space reducing means 52 is constituted by the convex portion 50 formed on the inside cover 22, the constitution is simple and the manufacture is easy, and
The cost can be reduced and it is economically advantageous.

The present invention is not limited to the above-mentioned first to third embodiments, and various application modifications are possible.

For example, in the second and third embodiments of the present invention, the concave portion 40 or the convex portion 50 serving as the space reducing means 42, 52 is formed on either the outside cover 20 or the inside cover 22. As shown in FIG. 8, a concave portion 60 and a convex portion 62 are formed on both the outside cover 20 and the inside cover 22 to a position where they substantially come into contact with each other during mounting, and the concave portion 60 and the convex portion 62 form the space reducing means 64. It is also possible to configure.

[0049]

As described above in detail, according to the present invention, a timing belt for transmitting the driving force from the crankshaft of the engine to the camshaft is provided, and the outside cover and the inside cover surrounding the timing belt are provided. In the timing belt cover, the space cover is formed inside by the outside cover and the inside cover, and the space reducing means for reducing the space portion is provided to reduce the noise of the timing belt. It is possible to reduce the resonance vibration in order to eliminate the peak frequency, and to reduce the noise of the timing belt without increasing the transmission of the radiation sound from the engine body side, which is practically advantageous. .. Further, when the space reducing means is configured, the structure is simple, so that the manufacturing is easy and the cost can be reduced, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a sectional view of a timing belt cover taken along the line 〓-〓 of FIG. 2 showing a first embodiment of the present invention.

FIG. 2 is a front view of a timing belt cover.

FIG. 3 is a schematic view of a Helmholtz type resonator having a communication hole portion arranged as a box-shaped member.

FIG. 4 is a sectional view of the timing belt cover taken along the line 〓-〓 of FIG. 5 showing the second embodiment of the present invention.

FIG. 5 is a front view of a timing belt cover.

FIG. 6 is a sectional view of a timing belt cover taken along line 〓-〓 of FIG. 7 showing a third embodiment of the present invention.

FIG. 7 is a front view of a timing belt cover.

FIG. 8 is a sectional view of a timing belt cover showing another embodiment of the present invention.

FIG. 9 is a schematic assembly perspective view of a timing belt cover in a normal engine showing a conventional technique of the present invention.

FIG. 10: XX of FIG. 11 showing the prior art of the present invention
It is sectional drawing of the timing belt cover by a line.

FIG. 11 is a front view of the timing belt cover.

FIG. 12 is a schematic assembly perspective view of a timing belt cover in a DOHC type engine.

FIG. 13 is a diagram showing a relationship between engine speed and timing belt noise.

FIG. 14 is a front view of a timing belt cover showing another conventional technique.

[Explanation of symbols]

 2 engine 4 cylinder head 6 cylinder block 8 crankshaft 10 camshaft 12 crankshaft pulley 14 camshaft pulley 16 timing belt 18 timing belt cover 20 outside cover 22 inside cover 24 space 28 space reducing means 30 box-shaped member

Claims (1)

[Claims] 1. A timing belt cover for an engine, comprising: a timing belt for transmitting a driving force from an engine crankshaft to a camshaft; and an outside cover and an inside cover surrounding the timing belt. A timing belt cover for an engine, characterized in that a space portion is formed inside by the inside cover and the inside cover, and space reducing means for reducing the space portion is provided to reduce noise of the timing belt.