JP4607038B2 - Engine cover - Google Patents

Description

  The present invention relates to an engine cover that covers a direct injection engine.

Conventionally, as this type of engine cover, one having a urethane foam resin layer on the lower surface of a synthetic resin cover body is known (see, for example, Patent Document 1).
JP 2001-99554 A (paragraphs [0010] to [0012])

  By the way, in recent years, quietness has been required even in a vehicle equipped with a direct injection type engine (for example, a diesel engine). However, the above-described conventional engine cover cannot obtain a sufficient soundproofing effect.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an engine cover that has higher soundproofing performance than a conventional direct-injection engine.

  The applicant of the present application has intensively studied, and as a result, a urethane foam resin layer (22) and a PET nonwoven fabric layer (23), and an air layer (24) between the urethane foam resin layer (22) and the PET nonwoven fabric layer (23). It has been found that the noise from the injector provided in the direct injection engine can be effectively absorbed, and the present invention according to claims 1 to 6 has been completed.

That is, the engine cover (20) according to the first aspect of the present invention includes a cover main body (21) that covers the direct injection engine (10) and a surface facing the direct injection engine (10) of the cover main body (21). The urethane foam resin layer (22) formed on the PET, the PET nonwoven fabric layer (23) formed by covering the urethane foam resin layer (22) with a PET nonwoven fabric (23S), the urethane foam resin layer (22) and the PET nonwoven fabric. And an air layer (24) formed between the layer (23) and the cover main body (21) through the urethane foam resin layer (22) and butted against the PET nonwoven fabric layer (23). Projection parts (25, 25V to 25Z) are provided, and are characterized in that the nonwoven fabric (23S) is vibration welded to the front end surface of the welding projection part (25) .

The invention according to claim 2 is the engine cover (20) according to claim 1, wherein a plurality of convex portions (22B) are adjacent to a surface of the urethane foam resin layer (22) facing the PET nonwoven fabric layer (23). The welding protrusions (25, 25V to 25Z) protrude from the bottom surfaces of the recesses (22C) between the adjacent protrusions (22B) .

A third aspect of the invention is the engine cover (20) according to the first or second aspect, wherein the engine cover (20) surrounds the welding protrusion (25) so as not to be buried in the urethane foam resin layer (22). The protrusion surrounding wall (26) is formed on the cover body (21), and the tip of the welding protrusion (25) is protruded from the protrusion surrounding wall (26) .

According to a fourth aspect of the present invention, in the engine cover (20) according to any one of the first to third aspects, the welding protrusion (25, 25V to 25Y) includes a plurality of protruding pieces (25A to 25C). ) Or an assembly of protrusions (25D).

  According to a fifth aspect of the present invention, in the engine cover (20) according to the fourth aspect, the welding protrusion (25) intersects a plurality of protrusions (25A, 25B) protruding from the cover body (21). It has a feature in the place.

The invention of claim 6 is characterized in that, in the engine cover (20) according to any one of claims 1 to 3 , the welding protrusions (25V, 25Z) are cylindrical bodies.

According to the structure of Claim 1, the noise from a direct injection type engine (10) can be absorbed and attenuated, and a higher soundproofing effect than before can be obtained. In addition, according to the present invention, the nonwoven fabric (23S) is vibration welded to the distal end surface of the welding projection (25, 25V to 25Z) protruding from the cover body (21), so the PET nonwoven fabric (23S) is urethane. Compared with the case of fixing directly to the foamed resin layer (22), the fixing strength of the nonwoven fabric made of PET (23S) can be increased.

According to the structure of Claim 2, since several convex part (22B) is formed adjacent to the opposing surface with a PET nonwoven fabric layer (23) among urethane foam resin layers (22), and it is uneven | corrugated shape . The sound reflection performance is improved by dispersing the sound reflection direction. Moreover, by making the welding projection (25, 25V to 25Z) protrude from the bottom surface in the recess (22C) between the adjacent projections (22B), the welding projection (25, 25V to 25Z) A front-end | tip part can be exposed from a urethane foam resin layer (22).

According to the structure of Claim 3 , a welding protrusion (25) can be exposed from a urethane foamed resin layer (22) by surrounding a welding protrusion (25) in a protrusion surrounding wall (26). .

  In the structure of Claim 4, since the welding protrusion (25, 25V-25Y) was made into the aggregate | assembly of several protrusions (25A-25C) or protrusion (25D), welding of the nonwoven fabric (23S) made from PET The welding protrusion (25, 25V to 25Y) that is the counterpart melts easily, and the heating time by vibration is shortened. Thereby, the melted amount of the nonwoven fabric (23S) made of PET can be suppressed, and a large amount of space is secured between the fibers of the nonwoven fabric (23S) even in the vicinity of the welded portion, so that soundproofing is improved. In the invention of claim 6 as well, since the welding protrusions (25V, 25Z) are cylindrical, the welding protrusion (25Z) is easily melted, and the soundproofing property is similarly improved.

  In the structure of Claim 5, since the welding protrusion (25) intersects the plurality of protrusions (25A, 25B) protruding from the cover body (21), the protrusions (25A, 25B) are mutually connected. Reinforcing each other increases the strength, and accordingly, the plate thickness of each protrusion (25A, 25B) can be reduced, and the welding protrusion (25) can be further melted.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a state in which the engine cover 20 of the present embodiment is viewed from the lower surface side. The engine cover 20 is provided with a urethane foam resin layer 22 and a PET nonwoven fabric layer 23 laminated on the lower surface of a synthetic resin cover body 21. And the engine cover 20 is being fixed to the engine 10 or its vicinity with the screw | thread not shown in the state which covered the upper surface of the engine 10, as shown in FIG. The engine 10 is a direct injection diesel engine equipped with a piezo injector.

  The state which looked at the cover main body 21 before the urethane foam resin layer 22 and the PET nonwoven fabric layer 23 are laminated | stacked from the lower surface side is shown by FIG. As shown in the figure, the cover main body 21 has a structure in which the surrounding wall 21B protrudes downward (upward in FIG. 2) from the outer edge portion of the substantially rectangular main plate portion 21A. Reinforcing ribs 21 </ b> C and a plurality of welding protrusions 25 are formed on the entire lower surface of the cover body 21. The reinforcing rib 21C is lower than the surrounding wall 21B.

As shown in an enlarged view in FIG. 3 , the welding protrusion 25 is formed by intersecting a plurality of protrusions 25 </ b> A and 25 </ b> B protruding from the lower surface of the cover body 21 in a lattice shape. Specifically, the welding protrusion 25 protrudes from the lower surface of the cover body 21 and is parallel to each other and extends in a first horizontal direction (direction H1 in FIG. 3), and a pair of protrusions 25A and 25A. A pair of projecting pieces 25B and 25B extending in a second horizontal direction (H2 direction in FIG. 3) orthogonal to the first horizontal direction are crossed, and the overall planar shape is “#” character or Chinese character "I" character shape. Horizontal length of the projecting pieces 25A, 25B is longer than the diameter of the distal end surface of the vibration welding tool (not shown). Moreover, the plate | board thickness of each protrusion 25A, 25B is thinner than 21 A of main board parts, and the reinforcing rib 21C. Furthermore, the welding protrusion 25 is higher than the reinforcing rib 21C and lower than the surrounding wall 21B.

  As shown in FIG. 1, a urethane foam resin 22J is molded on the entire lower surface of the cover body 21 to form a urethane foam resin layer 22, and the urethane foam resin layer 22 is made of a nonwoven fabric 23S made of PET (polyethylene terephthalate). A PET nonwoven fabric layer 23 is formed so as to cover it.

  As shown in an enlarged view in FIG. 4, a plurality of rounded substantially conical convex portions 22 </ b> B are formed adjacent to the entire surface of the urethane foam resin layer 22 on the engine 10 side. The concave and convex portion 22A according to the present invention is constituted by the concave portions 22C between the adjacent convex portions 22B and 22B. And the air layer 24 is formed between the urethane foam resin layer 22 and the PET nonwoven fabric layer 23 by this uneven part 22A. The reinforcing rib 21C (see FIG. 2) of the cover main body 21 is entirely covered with the urethane foam resin layer 22 regardless of the convex portion 22B and the concave portion 22C. On the other hand, as shown in FIG. 4, each welding projection 25 of the cover body 21 protrudes from the bottom surface of the recess 22C, and the front end surface of the welding projection 25 is disposed at substantially the same position as the apex of the projection 22B. Yes.

The nonwoven fabric 23 </ b> S constituting the PET nonwoven fabric layer 23 is vibration welded to the distal end surface of the welding protrusion 25 described above. When performing the vibration welding is laid PET nonwoven fabric made of 23S to overlap the foamed urethane resin layer 22, between the front end surface of the vibration welding tool (not shown) with the front end surface of the welding projection 25 of the rod-shaped The nonwoven fabric 23S is crushed. In this state, a predetermined time, by vibrating the vibration welding tool, the contact portion between the nonwoven fabric 23S and the welding protrusions 25 are welded to melt. Incidentally, the vibration welding tool when disengaging from the nonwoven 23S, a state in which the vibration welding tool Similar crushed have portions are remained shallow depression restoring of nonwoven 23S.

  This is the end of the description of the configuration relating to the engine cover 20 of the present embodiment. According to the engine cover 20 of the present embodiment, the noise from the direct injection type engine 10 is absorbed and attenuated as can be confirmed in the following examples, and a higher soundproofing effect than before can be obtained. Moreover, by forming the uneven portion 22A on the PET nonwoven fabric layer 23, the sound reflection direction is dispersed and the sound absorbing performance is improved. Furthermore, since the welding protrusion 25 penetrating the urethane foam resin layer 22 is formed on the cover body 21 and the nonwoven fabric 23S is vibration welded to the front end surface of the welding protrusion 25, the nonwoven fabric 23S is bonded to the urethane foam resin layer 22. The fixing strength of the nonwoven fabric 23S can be increased as compared with the case where the nonwoven fabric 23 is fixed. And since the welding protrusion 25 was comprised with the aggregate | assembly of several protrusion piece 25A, 25B, the front end surface of the welding protrusion 25 melt | dissolves easily, and the heating time by vibration becomes short. Thereby, the melted amount of the nonwoven fabric 23S made of PET can be suppressed, and a large space is secured between the fibers of the nonwoven fabric 23S even in the vicinity of the welded portion, so that the soundproofing property is improved. Further, since the plurality of projecting pieces 25A and 25B constituting the welding projection 25 intersect, the projecting pieces 25A and 25B reinforce each other to increase the strength. The plate thickness can be reduced, and the welding projection 25 can be further melted.

[Example]
The implementation product 1 according to the present invention is shown in FIG. 5, and the urethane foam resin layer 22, the PET nonwoven fabric layer 23, and the acrylic plate AC as the “cover body” of the present invention, as in the first embodiment. Are laminated. Here, the thickness t1 of the acrylic plate AC is 3 [mm], the thickness t2 of the urethane foam resin layer 22 is 10 [mm], and the height between the top of the convex portion 22B and the bottom of the concave portion 22C of the urethane foam resin layer 22 is high. The difference t3 is 5 [mm], and the thickness t4 of the nonwoven fabric 23S is 15 [mm]. The mass of the urethane foam resin layer 22 is 154 [g], and the mass of the PET nonwoven fabric layer 23 is 165 [g] (the total mass of the urethane foam resin layer 22 and the PET nonwoven fabric layer 23 is 319 [g]. is there). On the other hand, the comparative product 1 in which only the above-mentioned 154 [g] urethane foam resin layer 22 is laminated on the above-mentioned acrylic plate AC, and the above-mentioned PET nonwoven fabric layer 23 of 165 [g] on the above-mentioned acrylic plate AC only. The laminated comparative product 2 was manufactured, and the following comparative experiments 1 and 2 were performed.

(Comparative Experiment 1)
The implementation product 1 and the comparison products 1 and 2 are sequentially housed in a predetermined housing, and the sound generated at a predetermined position of the housing is output from a hole provided at another position of the housing. The graph of FIG. 6 was created by measuring how much it attenuated during the period up to.

  As is apparent from the graph of FIG. 6, when the embodiment product 1 is housed in the housing, the volume is attenuated more than the comparison products 1 and 2 over the range of 500 to 8,000 [Hz]. . That is, it was confirmed that the implementation product 1 had a higher sound absorption effect than the comparison products 1 and 2.

(Comparative experiment 2)
Example 1 and comparative products 1 and 2 were sequentially attached to a direct-injection engine (diesel engine) equipped with a piezo injector, and noise was measured at a position separated by a predetermined distance to create the graph of FIG.

  As can be seen from the graph of the same figure, it was confirmed that the soundproofing effect of the implemented product was higher than that of the comparative products 1 and 2 over the range of 500 to 20,000 [Hz].

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In addition to the structure of the above-described embodiment, the welding protrusion 25 extends 1 in the first horizontal direction, for example, as the welding protrusion 25V shown in the plan view of FIG. The pair of projecting pieces 25A and 25A and a pair of projecting pieces 25B and 25B extending in the second horizontal direction may be joined in a rectangular frame shape. That is, the entire shape may be a square tube like the welding protrusion 25V.

  (2) Further, like the welding protrusion 25W shown in the plan view of FIG. 8 (B), it may be configured by only a pair of protrusions 25A and 25A extending in parallel with each other.

  (3) Moreover, you may make it the structure which joined the five protrusion pieces 25C to the star shape like the welding protrusion 25X shown to the top view of FIG.8 (C).

  (4) Moreover, you may comprise by the aggregate | assembly of several protrusion 25D with circular cross-section like the welding protrusion 25Y shown to the top view of FIG.8 (D).

  (5) Furthermore, like the welding projection 25Z shown in the plan view of FIG. 8 (E), it may have a cylindrical shape.

  (6) As shown in FIG. 9, a cylindrical projecting wall 26 is formed so as to surround the welding projection 25 so that the base end of the welding projection 25 is not buried in the urethane foam resin 22J. May be.

The perspective view of the engine cover which concerns on one Embodiment of this invention. Perspective view of the cover body Perspective view of welding protrusion Cross section of engine cover Cross section of the engine cover product Graph comparing sound absorption effect Graph comparing soundproofing effect The top view of the welding protrusion in other embodiment Sectional drawing of the engine cover in other embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 20 Engine cover 21 Cover main body 22 Urethane foamed resin layer 22A Uneven part 23 PET nonwoven fabric layer 23S PET nonwoven fabric 24 Air layer 25,25V-25Z Welding projection 25A-25C Projection piece 25D Protrusion

Claims (6)

A cover body (21) covering the direct injection engine (10);
A urethane foam resin layer (22) formed on a surface of the cover body (21) facing the direct injection engine (10);
A PET nonwoven fabric layer (23) formed by covering the urethane foam resin layer (22) with a PET nonwoven fabric (23S);
An air layer (24) formed between the urethane foam resin layer (22) and the PET nonwoven fabric layer (23) ;
The cover body (21) includes a welding protrusion (25, 25V to 25Z) that penetrates the urethane foam resin layer (22) and is abutted against the PET nonwoven fabric layer (23). The engine cover (20) , wherein the nonwoven fabric (23S) is vibration welded to the tip surface of the protrusion (25 ). A plurality of convex portions (22B) are formed adjacent to the surface of the urethane foam resin layer (22) facing the PET nonwoven fabric layer (23), and the concave portions (22B) between the adjacent convex portions (22B) ( The engine cover (20) according to claim 1, wherein the welding protrusion (25, 25V to 25Z) protrudes from the bottom surface in 22C) . Forming a cylindrical projection-enclosing wall (26) on the cover body (21) for surrounding the welding projection (25) so as not to be buried in the urethane foam resin layer (22), The engine cover (20) according to claim 1 or 2, wherein a tip end portion of the welding protrusion (25) is protruded from the protrusion surrounding wall (26 ). The said welding protrusion (25,25V-25Y) is an aggregate | assembly of several protrusions (25A-25C) or protrusion (25D), The claim of any one of Claim 1 thru | or 3 characterized by the above-mentioned. The engine cover (20) described in 1.   The engine cover (20) according to claim 4, wherein the welding protrusion (25) is formed by intersecting a plurality of protrusions (25A, 25B) protruding from the cover body (21). The engine cover (20) according to any one of claims 1 to 3, wherein the welding protrusion (25V, 25Z) is a cylindrical body.

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