Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B77/00—Component parts, details or accessories, not otherwise provided for
  • F02B77/11—Thermal or acoustic insulation
  • F02B77/13—Acoustic insulation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F7/00—Casings, e.g. crankcases or frames
  • F02F7/0065—Shape of casings for other machine parts and purposes, e.g. utilisation purposes, safety
  • F02F7/008—Sound insulation

Definitions

• the present invention relates to a cover member mounted on an internal combustion engine.
• the present invention also relates to an internal combustion engine equipped with such a cover member.
• Patent Document 1 describes an engine undercover obtained by molding a urethane foam on a resinous cover main body.
• the sound of the engine is absorbed by the urethane foam on the inside, and design properties and sound insulation with respect to noise can be realized by means of the cover main body on the outside.
• a cover member according to the present invention comprises a resin or an elastomer and is mounted on an internal combustion engine, and is characterized in that it comprises: an outside portion including an outer surface; an inside portion positioned on a rear side of the outside portion; and a joining portion which is positioned on the rear side of the outer periphery of the outside portion and is bonded to the internal combustion engine, wherein the outside portion comprises a closed-cell structure which is non-foamed or has a low foaming rate, the inside portion comprises an open-cell structure with a high foaming rate, and the joining portion comprises a closed-cell structure with a high foaming rate.
• the foaming rate or foam structure of each part of the cover member by varying the foaming rate or foam structure of each part of the cover member, it is possible to impart a different function to each section without increasing the number of components or using different materials for each section, and this is achieved inexpensively and without producing an increase in weight.
• FIG. 1 is an explanatory diagram schematically illustrating the positional relationship of an internal combustion engine and a cover member.
• FIG. 2 is a view in cross section of the cover member according to the present invention.
• a cover member 1 As shown in fig. 1 and fig. 2, a cover member 1 according to the present invention is mounted on a side surface of an internal combustion engine 2 using bolts (not depicted) or the like, for example.
• the left/right direction in fig. 1 is a cylinder line direction of the internal combustion engine 2.
• the cover member 1 is an integrally molded article comprising a resin or an elastomer, and comprises an outside portion 3, an inside portion 4, and a joining portion 5. That is to say, the cover member 1 is a molded article in which the outside portion 3, inside portion 4 and joining portion 5 comprise the same material, namely a resin or an elastomer.
• the cover member 1 according to this exemplary embodiment is an integrally molded article made of urethane foam.
• the outside portion 3 is a portion on the outside including an outer surface 6 of the cover member 1, and has a closed- cell (isolated-cell) structure with a low foaming rate.
• the outside portion 3 having a closed-cell (isolated-cell) structure has closed cells (isolated cells) in which the bubbles contained therein are isolated from each other.
• the inside portion 4 is positioned on a rear side of the outside portion 3 and comprises a plurality of holes 7 whereof an opening on one end side faces the internal combustion engine 2.
• the inside portion 4 is a portion on the inside of the cover member 1 which is covered by the outside portion 3 and has an open-cell (interconnected-cell) structure with a high foaming rate. To describe this in detail, the inside portion 4 is covered by the outside portion 3 except on an exposed surface 8 facing the internal combustion engine 2.
• the inside portion 4 having an open cell (interconnected-cell) structure has open cells (interconnected cells) in which the bubbles contained therein are connected to each other.
• the holes 7 are formed in such a way that one end thereof is open on the exposed surface 8 while another end thereof does not reach the outside portion 3, and they are formed in such a way that the diameter thereof is 5 mm or greater and the length thereof is 10-200 mm, for example. Furthermore, the holes 7 function as a side-branch type resonator, and the length and number thereof are set in such a way as to be able to silence a target frequency (e.g., 500-5000 Hz).
• a target frequency e.g., 500-5000 Hz
• An inner peripheral surface of the holes 7 and the exposed surface 8 of the inside portion 4 constitute portions contacted by a die during molding of the cover member 1, and therefore comprise a skin having a uniform and continuous surface form.
• the joining portion 5 is a portion which is bonded to the internal combustion engine 2 when the cover member 1 is mounted on the internal combustion engine 2, and comprises a closed-cell (isolated-cell) structure with a high foaming rate.
• the joining portion 5 having a closed-cell (isolated cell) structure has closed cells (isolated cells) in which the bubbles contained therein are isolated from each other.
• the joining portion 5 is formed in such a way as to be positioned on a rear side of the outer periphery of the outside portion 3. To describe this in detail, the joining portion 5 is formed in such a way as to be positioned on the outside of the inside portion 4 and to surround the periphery of the inside portion 4. Furthermore, the joining portion 5 is formed in such a way as to be continuous along the whole periphery of the rear side of the outer periphery of the outside portion 3.
• the joining portion 5 is formed in such a way that a pressing surface 9 which is pressed against the internal combustion engine 2 protrudes further to the internal combustion engine 2 side in a natural state than a rear surface 10 of an outer peripheral edge of the outside portion 3 and the exposed surface 8 of the inside portion 4.
• the pressing surface 9 in a state in which the pressing surface 9 is bonded to the internal combustion engine 2 when the joining portion 5 is mounted on the internal combustion engine 2, the pressing surface 9 need not protrude further to the internal combustion engine 2 side in a natural state than the rear surface 10 of the outer peripheral edge of the outside portion 3 and the exposed surface 8 of the inside portion 4.
• the pressing surface 9 of the joining portion 5 constitutes a portion contacted by the die during molding of the cover member 1, and therefore comprises a skin having a uniform and continuous surface form.
• the cover member 1 employs a polyol, a polyisocyanate and other materials as the starting material thereof.
• the closed cells (isolated cells) and open cells (interconnected cells) may be separately formed by controlling the rate of foaming by varying the mixing proportions of the abovementioned starting materials.
• the outside portion 3 is molded in such a way as to form a urethane foam controlled to have closed cells (isolated cells) with a foaming rate of 10-40 times.
• the void content of the outside portion 3 is around 90-98% when calculated from the foaming rate.
• the inside portion 4 is molded in such a way as to form a urethane foam controlled to have open cells (interconnected cells) with a foaming rate of 10-150 times.
• the void content of the inside portion 4 is around 90-99% when calculated from the foaming rate.
• the joining portion 5 is molded in such a way as to form a urethane foam controlled to have closed cells (isolated cells) with a foaming rate of 10-150 times.
• the void content of the joining portion 5 is around 90-99% when calculated from the foaming rate.
• the cover member 1 according to the exemplary embodiment described above makes it possible to improve the design properties and sound insulation by virtue of the fact that the outside portion 3 has a closed-cell (isolated-cell) structure with a low foaming rate.
• the outside portion 3 still makes it possible to improve the design properties and sound insulation even if it is molded in such a way as to have a non-foamed structure.
• a non-foamed structure is a solid structure without internal bubbles.
• the inside portion 4 has an open-cell (interconnected-cell) structure with a high foaming rate. That is to say, it is possible to improve the sound absorption function in the interior of the cover member 1.
• the joining portion 5 has a closed-cell (isolated-cell) structure with a high foaming rate. It should be noted that if the pressing surface 9 is covered by a skin having a uniform and continuous surface form, then the joining portion 5 may be molded in such a way as to form a urethane foam controlled to have open cells (interconnected cells), for example.
• the cover member 1 By varying the foaming rate or foam structure (closed-cell structure, open-cell structure, non-foamed structure) of each part in accordance with the purpose thereof, the cover member 1 makes it possible to impart a different function to each section without increasing the number of components or using different materials for each section, and this is achieved inexpensively and without producing an increase in weight .
• the exposed surface 8 of the inside portion 4 facing the internal combustion engine 2 is in a state in which it is covered by a skin having a uniform and continuous surface form, but a plurality (large number) of through-holes communicating with the open cells of the inside portion 4 may be formed in this skin, or this skin may be removed by stripping or the like so that the open cells forming the open-cell structure of the inside portion 4 are open on the exposed surface 8.
• cover member 1 is used as a side cover of an internal combustion engine 2, but the cover member 1 may equally be mounted on a portion other than the side surface of the internal combustion engine 2.
• the joining portion 5 is formed in such a way as to be continuous along the whole periphery of the rear side of the outer periphery of the outside portion 3, but the joining portion 5 may equally be formed intermittently on the rear side of the outer periphery of the outside portion 3, depending on the shape etc. of the internal combustion engine 2 on which the cover member 1 is mounted.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Body Structure For Vehicles (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

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Citations (6)

Family Cites Families (3)

• 2017
  • 2017-11-21 JP JP2017223273A patent/JP2019094807A/ja active Pending
• 2018
  • 2018-11-12 WO PCT/EP2018/080919 patent/WO2019101561A1/en active Search and Examination
  • 2018-11-12 EP EP18800939.3A patent/EP3714145A1/en not_active Withdrawn

Patent Citations (6)

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