JP2010236412A - Engine cover structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine cover structure providing a radiated sound suppressing effect by a simple structure, suppressing enlargement of an engine cover, and suppressing an increase in plate thickness. <P>SOLUTION: A timing chain cover 17 (cover member) covers the cylinder block 2 of an internal combustion engine. The surface 18 of the timing chain cover 17 on a side opposite to the cylinder block 2 and the rear surface 19 thereof on the side of the cylinder block 2 are respectively composed of three or more kinds of component surfaces 20, 21, 22 and component surfaces 25, 26, 27, which are different in height and in the initial phase of vibration of a radiated sound. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an engine cover structure that covers a cylinder block or the like of an internal combustion engine and suppresses radiation noise.

  As a conventional engine cover structure, a vibration damping plate with multiple plates stacked in close contact (relatively displaceable) is attached to the chain cover, and when vibration occurs, vibration energy is generated by each plate sliding relative to the left and right. Is generated by friction (thermal energy), and the generation of radiated sound from the chain cover is suppressed (for example, see Patent Document 1).

  In addition, a damping plate is connected to the ring formed on the inner surface of the chain cover in a lid shape to form a space portion, and a communication hole is set between the space portion and the inner space of the chain cover. The specific frequency is determined by the space portion and the communication hole to reduce vibration and noise at the specific frequency of the engine (see, for example, Patent Document 2).

  Also, the wall portion around the crankshaft hole has an arcuate curved cross-sectional shape surrounding the crankshaft hole, and is curved by a radial rib that connects the fastening boss portion of the outer peripheral edge portion of the chain cover and the peripheral edge portion of the crankshaft hole. There is one that cuts the cross-section portion into a plurality of curved portions and reduces noise caused by membrane vibration of the wall portion generated by transmission of vibration accompanying rotation of the crankshaft (see, for example, Patent Document 3).

  Further, in the wall surface structure of a structural body such as a cylinder block of an internal combustion engine, it is generally composed of a plate-shaped plate body, and concave and convex portions are alternately arranged adjacent to both surfaces of the plate body, On the opposite side of the convex portion of the surface, a concave portion of the other surface is formed, and the concave portion and the convex portion are integrally connected to each other by a connecting portion (see, for example, Patent Document 4).

JP 2008-106809 A JP 2000-8950 A JP 2002-339759 A Japanese Utility Model Publication No. 56-21637

  However, since the conventional technology of Patent Document 1 uses the friction of the damping plate in which the plate materials are laminated for the energy conversion from vibration to heat, the conversion efficiency to the heat energy is increased due to the wear of the sliding surface due to deterioration over time. There is a risk that the radiated sound suppression effect will deteriorate. In addition, the generation of wear powder due to friction may have an adverse effect on peripheral devices due to foreign matter contamination. Furthermore, there is a possibility that the plate materials laminated by heat energy are welded and cannot be converted into heat energy.

  Further, in the prior art of Patent Document 2, since it is necessary to secure a space volume for acting as a resonator in a space formed by the annular connecting rib and the damping plate, the chain cover is enlarged, and the annular connecting rib and the damping are reduced. Engine oil tends to accumulate in the space formed by the plate, and the engine oil may deteriorate.

  Moreover, in the prior art of Patent Document 3, in order to obtain an effective membrane vibration suppression effect with respect to membrane vibration suppression by setting only the ribs, a sufficient space capable of giving sufficient curvature to the curved cross section is necessary. Thus, there is a problem that a curved cross section that can obtain a sufficient effect cannot be set at a site where an adjacent object exists.

  Further, in the prior art of Patent Document 4, it is necessary to increase the concave amount (total thickness of the plate) in order to ensure sufficient bending strength, and the total thickness of the plate is “thin plate + rib arrangement”. There is no difference. Moreover, if the dimension shape of an adjacent recessed part and a convex part is changed, a connection part will become large and mass will increase. Further, since the concave portions and the convex portions are alternately arranged, there is a problem that the degree of freedom in arranging the dimensional shape is small.

  The present invention has been made in view of the above-described problems, and provides an engine cover structure which can obtain a radiation noise suppressing effect with a simple structure, suppress an increase in the size of the engine cover, and suppress an increase in plate thickness. For the purpose.

  A first problem-solving means of the present invention is a cover member that covers a part of an internal combustion engine, wherein the cover member includes at least a back surface that is the internal combustion engine side and a surface that is the opposite side to the internal combustion engine. Either one is composed of three or more kinds of different heights of the different planes of the radiated sound vibration.

  Further, the second problem solving means is configured such that the total area of each of the constituent surfaces is substantially the same.

  In the third problem solving means, the constituent surfaces are provided on the back surface and the front surface of the cover member, and the thickness between the back surface and the front surface is substantially the same.

  The fourth problem-solving means is configured such that the configuration surface is different between the back surface and the front surface of the cover member, and the radiated sound of the back surface has a higher frequency than the radiated sound of the front surface.

  In the present invention, the cover member has at least one of the back surface on the internal combustion engine side and the surface on the opposite side of the internal combustion engine and has three or more types of different heights with different initial phases of radiated sound vibrations. Is provided. By setting it as three or more types of component surfaces, the area of the component surface per one becomes small compared with the area when the back surface or surface of a cover member is made into a single surface. By reducing the area, the amplitude of the radiated sound on one component surface is reduced and the frequency becomes high. In addition, the initial phase of the vibration of the radiated sound is different on the component surface, so that overlapping at the maximum amplitude of the waveform can be prevented and the maximum amplitude of the synthesized wave can be lowered. Therefore, a radiated sound suppression effect can be obtained with a simple structure, and an increase in the thickness of the engine cover can be suppressed and an increase in plate thickness can be suppressed.

  Further, by configuring so that the total area of each component surface is substantially the same, the radiated sound from each component surface becomes a waveform having substantially the same amplitude at substantially the same frequency with different initial phases. Therefore, overlapping of waveforms can be prevented, the maximum amplitude of the combined wave can be reduced, and resonance of radiated sound from each component surface can be prevented.

  Further, by providing the constituent surfaces on the back surface and the front surface of the cover member and making the thickness between the back surface and the front surface substantially the same, waveforms having substantially the same amplitude at substantially the same frequency with different initial phases can be obtained. Moreover, the enlargement of a cover member and the increase in plate | board thickness can be suppressed. In addition, when the cover member is manufactured by die casting using an aluminum material or the like, the hot water flow is good and the manufacturing quality is improved. Further, since a plurality of constituent surfaces can be formed on the front surface and the back surface of the cover member in a single manufacturing process, productivity is improved.

  Further, the configuration surface is different between the back surface and the front surface of the cover member, and the radiated sound on the back surface has a higher frequency than the radiated sound on the front surface. Sound with high frequency is easily attenuated in the air and difficult to pass through the opening, so that the sound insulation effect of the entire engine is improved.

1 is a perspective view of an engine to which an engine cover member according to an embodiment of the present invention is applied. FIG. 2 is a side view of the engine shown in FIG. 1 with a timing chain cover and a head cover removed. It is a front view of the camshaft drive mechanism of the engine shown in FIG. It is a conceptual diagram of the cover member of the engine which concerns on the Example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a timing chain cover of the engine which concerns on the Example of this invention, (a) is a partial expansion perspective view, (b) is AA sectional drawing. It is explanatory drawing which shows the state of the radiated sound from the structure surface of the surface of a timing chain cover. It is explanatory drawing which shows the waveform of a radiated sound, (a) is a waveform of the radiated sound in case a timing chain cover is a plane, (b) is a waveform of the radiated sound radiated | emitted from a structural surface. FIG. 6 is a timing chain cover for an engine according to Modification 1 of the present invention, in which (a) is a partially enlarged perspective view and (b) is a BB cross-sectional view. FIG. 6 is a timing chain cover for an engine according to Modification 2 of the present invention, in which (a) is a partially enlarged perspective view and (b) is a CC cross-sectional view. FIG. 6 is a timing chain cover for an engine according to Modification 3 of the present invention, in which (a) is a partially enlarged perspective view and (b) is a DD cross-sectional view. FIG. 6 is a timing chain cover for an engine according to Modification 4 of the present invention, in which (a) is a partially enlarged perspective view of the front surface, (b) is a sectional view taken along line EE, and (c) is a partially enlarged perspective view of the back surface.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a perspective view of an engine 1 to which a timing chain cover 17 (cover member) of the present invention is applied. In the engine 1, a head cover 4 is fastened to an upper part of a cylinder block 2 via a cylinder head 3, and an oil pan 6 is fastened to a lower part of the cylinder block 2 via a crankcase 5.

  FIG. 2 is a side view of the engine 1 with the timing chain cover 17 and the head cover 4 removed. A crankshaft 7 is rotatably disposed in the crankcase 5, and a crank sprocket 8 is integrally connected to one end side of the crankshaft 7. In addition, an intake camshaft 9 and an exhaust camshaft 10 are rotatably arranged on the cylinder head 3, and an intake cam sprocket 11 is integrally connected to one end side of the intake camshaft 9, and the exhaust camshaft An exhaust cam sprocket 12 is integrally connected to one end side of 10.

  FIG. 3 is a front view of the camshaft drive mechanism 16 of the engine 1. The camshaft drive mechanism 16 is a chain tensioner in which a timing chain 13 for transmitting the rotation of the crankshaft 7 to the camshafts 9 and 10 is wound around the crank sprocket 7 and the cam sprockets 11 and 12 and the tension of the timing chain 13 is adjusted. A mechanism 14 and a chain guide 15 arranged between the cam sprockets 11 and 12 and the crank sprocket 7 for guiding the timing chain 13 are provided. The timing chain cover 17 is fastened to one end face side (front face side) of the engine 1 so as to include the camshaft drive mechanism 16.

  FIG. 4 is a conceptual diagram of the timing chain cover 17 of the engine 1 according to the embodiment of the present invention. In the timing chain cover 17, the surface 18 excluding the outer peripheral edge portion having the fastening boss portion is composed of four general surfaces 18a, 18b, 18c, and 18d.

  FIG. 5 is a timing chain cover 17 of the engine 1 according to the embodiment of the present invention, in which (a) is a partially enlarged perspective view and (b) is an AA cross-sectional view. The four general surfaces 18a, 18b, 18c, and 18d of the surface 18 are composed of three types of component surfaces 20, 21, and 22. The description will be made with the same shaded pattern attached to the same height of the configuration surface. The component surfaces 20, 21, and 22 have different heights, the component surface 21 is located at a height that is lowered from the component surface 20 by a step 23, and the component surface 22 is located at a height that is lowered from the component surface 20 by a step 24. Further, the total area of each of the three types of configuration surfaces 20, 21, and 22 is configured to be substantially the same.

  Similarly to the front surface 18, the back surface 19 of the timing chain cover 17 is composed of three types of constituent surfaces 25, 26, and 27 having different heights. The component surface 26 is positioned at a height lower than the component surface 25 by a step 28, and the component surface 27 is positioned at a height lower than the component surface 25 by a step 29. In addition, the total area of each of the three types of configuration surfaces 25, 26, and 27 is configured to be substantially the same.

  The thicknesses t1, t2, and t3 between the constituent surfaces 20, 21, and 22 of the front surface 18 of the timing chain cover 17 and the constituent surfaces 25, 26, and 27 of the back surface 19 are the same.

  FIG. 6 is an explanatory diagram showing the state of the dense wave of air radiated from the component surfaces 20, 21, 22 of the surface 18 of the timing chain cover 17. From the constituent surfaces 20, 21, and 22, dense waves having different initial phases of vibration are radiated.

  7A and 7B are explanatory diagrams showing the waveform of the radiated sound, where FIG. 7A is a waveform of the radiated sound when the timing chain cover is a single plane, and FIG. 7B is the radiation radiated from the component surfaces 20, 21, and 22. It is a sound waveform. The waveform in the case of a single plane is a waveform 30 having a large amplitude (sound pressure). On the other hand, the radiated sound from the constituent surfaces 20, 21, and 22 has waveforms 31, 32, and 33 with small amplitude (sound pressure). Since the constitutive surfaces 20, 21, and 22 have different initial phases in the waveforms 31, 32, and 33 of the radiated sound, overlapping of the waveforms 31, 32, and 33 at the maximum amplitude is prevented, and the maximum amplitude of the synthesized wave is reduced.

  In the present invention, the timing chain cover 17 is provided with three or more types of constituent surfaces 20, 21, 22, 25, 26, 27 having different initial phases of the radiated sound on the back surface 19 and the front surface 18. . By setting the three types of component surfaces 20, 21, 22, and 25, 26, 27, the area of each component surface 20, 21, 22, 25, 26, 27 is the area of the back surface 19 or the surface 18. Smaller than By reducing the area, the amplitude of the radiated sound at each component surface 20, 21, 22, 25, 26, 27 is reduced. In addition, since the height of the component surfaces 20, 21, 22, 25, 26, and 27 is determined so that the initial phase of the vibration of the radiated sound is different, the overlapping of the waveforms 31, 32, and 33 at the maximum amplitude is prevented, Reduce the maximum amplitude of the composite wave. Therefore, a radiated sound suppression effect can be obtained with a simple structure, the size of the timing chain cover 17 can be suppressed, and an increase in plate thickness can be suppressed.

  In addition, since the total area of each of the component surfaces 20, 21, 22 and 25, 26, 27 is substantially the same, the component surfaces 20, 21, 22, and 25, 26, 27 are separated from each other. The radiated sound has waveforms 31, 32 and 33 having substantially the same amplitude and substantially the same frequency with different initial phases. Therefore, the overlapping of the waveforms 31, 32, 33 at the maximum amplitude is prevented, the maximum amplitude of the combined wave is lowered, and the resonance of the radiated sound from the respective constituent surfaces 20, 21, 22, 25, 26, 27 is prevented. Can be prevented.

  Also, the constituent surfaces 20, 21, 22, 25, 26, and 27 are provided on the back surface 19 and the front surface 18 of the timing chain cover 17, and the thicknesses t1, t2, and t3 are the same, so that the initial phases are substantially the same. Waveforms 31, 32, and 33 having substantially the same amplitude in frequency are obtained. In addition, an increase in the size of the timing chain cover 17 and an increase in the plate thickness can be suppressed. In addition, when the timing chain cover 17 is manufactured by die casting using an aluminum material or the like, the hot water flowability is good and the manufacturing quality is improved. Further, since a plurality of constituent surfaces 20, 21, 22, 25, 26, and 27 can be formed on the front surface 18 and the back surface 19 of the timing chain cover 17 in a single manufacturing process, productivity is improved.

(Modification 1)
FIG. 8 is a timing chain cover 17a of the engine 1 according to the first modification of the present invention, in which (a) is a partially enlarged perspective view and (b) is a BB cross-sectional view. Functions and parts common to the timing chain cover 17 of FIG. 5 are denoted by common reference numerals, and differences in configuration and effects thereof will be described. Further, the description will be given with the same shaded pattern attached to the constituent surfaces having the same height. The difference from the timing chain cover 17 of FIG. 5 is that only the surface 18 is configured with three types of configuration surfaces 20, 21, and 22, and the other configurations are the same.

  The constituent surfaces 20, 21, and 22 of the surface 18 of the timing chain cover 17a have different heights, the constituent surface 21 is at a level lower than the step 23 from the constituent surface 20, and the constituent surface 22 is from the constituent surface 20 to the step 24. Located at a lowered height. Further, the total area of each of the three types of configuration surfaces 20, 21, and 22 is configured to be substantially the same.

  In the timing chain cover 17a, since the back surface 19 is flat, the cost of the timing chain cover 17a can be reduced, and the radiated sound from the front surface 18 can be suppressed.

(Modification 2)
FIG. 9 is a timing chain cover 17b of the engine 1 according to the second modification of the present invention, in which (a) is a partially enlarged perspective view and (b) is a CC cross-sectional view. Functions and parts common to the timing chain cover 17 of FIG. 5 are denoted by common reference numerals, and differences in configuration and effects thereof will be described. Further, the description will be given with the same shaded pattern attached to the constituent surfaces having the same height. The difference from the timing chain cover 17 of FIG. 5 is that one of the three types of constituent surfaces formed on the surface 18 is used as the reference surface 34.

  The surface 18 includes a reference surface 34 (configuration surface), a configuration surface 35, and a configuration surface 36. The component surface 35 is located at a height lower than the reference surface 34 by a step 37, and the component surface 36 is located at a height lower than the reference surface 34.

  In the timing chain cover 17b, the reference surface 34 acts as a rib to reduce the radiated sound from the surface 18 of the timing chain cover 17b and improve the rigidity.

(Modification 3)
FIG. 10 is a timing chain cover 17c of the engine 1 according to the third modification of the present invention, in which (a) is a partially enlarged perspective view and (b) is a DD cross-sectional view. Functions and portions common to the timing chain cover 17b of FIG. 9 are denoted by common reference numerals, and differences in configuration and effects thereof will be described. Further, the description will be given with the same shaded pattern attached to the constituent surfaces having the same height. The difference from the timing chain cover 17b of FIG. 9 is that the back surface 19 is also provided with three types of constituent surfaces, and one of the constituent surfaces is used as a reference surface 39.

  The surface 18 includes a reference surface 34 (configuration surface), a configuration surface 35, and a configuration surface 36. The component surface 35 is located at a height lower than the reference surface 34 by a step 37, and the component surface 36 is located at a height lower than the reference surface 34. The back surface 19 includes a reference surface 39 (configuration surface) and configuration surfaces 40 and 41. The component surface 40 is located at a height lower than the reference surface 39 by a step 42, and the component surface 41 is located at a height lower than the reference surface 39 by a step 43.

  In the timing chain cover 17c, the reference surfaces 34 and 39 act as ribs to reduce radiation sound from the front surface 18 and the back surface 19 of the timing chain cover 17c and improve rigidity.

(Modification 4)
11A and 11B show a timing chain cover 17d of the engine 1 according to Modification 4 of the present invention, in which FIG. 11A is a partially enlarged perspective view of the front surface, FIG. It is a perspective view. Functions and portions common to those of the timing chain cover 17 of FIG. 5 are denoted by common reference numerals, and differences in configuration and effects thereof will be described. Further, the description will be given with the same shaded pattern attached to the constituent surfaces having the same height. A difference from the timing chain cover 17 of FIG.

  The surface 18 includes a reference surface 44 (configuration surface) and configuration surfaces 45 and 46. The component surface 45 is located at a height lower than the reference surface 44 by a step 47, and the component surface 46 is located at a height lower than the reference surface 44 by a step 48. The back surface 19 is composed of component surfaces 49, 50 and 51. The component surface 50 is positioned at a height lower than the component surface 49 by a step 52, and the component surface 51 is positioned at a height lower than the component surface 49 by a step 53.

  In the modified example 4, the surface 18 and the back surface 19 of the timing chain cover 17d can be configured to have different shapes and the like, and the radiated sound of the back surface 19 has a higher frequency than the radiated sound of the front surface 18. Configured. Sound with a high frequency is easily attenuated in the air and hardly passes through the opening, so that the sound insulation effect of the entire engine 1 can be obtained.

  The present invention is not limited to the above-described embodiments and modifications, and includes a wide variety of modifications. For example, in the above-described embodiment and modification, the configuration surface has a quadrangular shape, but this is not a limitation. Further, the arrangement of the component surfaces may not be constant, and the size and shape of the component surfaces may not be the same.

  Further, in the above-described embodiment, the case where the present invention is applied to the timing chain cover that covers a part of the internal combustion engine is exemplified, but the present invention is applied to other cover members such as a cylinder head cover that covers a part of the internal combustion engine. You can also.

2 Cylinder block 17 Timing chain cover (cover member)
18 surface 19 back surface 20, 21, 22 component surface t1, t2, t3 thickness

Claims (4)

A cover member covering a part of the internal combustion engine,
The cover member has at least one of a back surface on the internal combustion engine side and a surface on the opposite side of the internal combustion engine, and has three or more types of different heights with different initial phases of radiated sound vibrations. An engine cover structure characterized by comprising. The engine cover structure according to claim 1, wherein the total area of each of the component surfaces is substantially the same. The said structure surface is provided in the said back surface and the said surface of the said cover member, and the thickness between the said back surface and the said surface is substantially the same, Either of Claim 1 or Claim 2 characterized by the above-mentioned. The engine cover structure described. 4. The engine cover structure according to claim 3, wherein the component surface has different configurations on the back surface and the front surface of the cover member, and the radiated sound on the back surface has a higher frequency than the radiated sound on the front surface. .

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