Sound absorbing cover structure

Abstract

In a sound absorbing cover structure according to the present invention, a first bolt fastening section (221) and a second bolt fastening section (222) are connected by a connecting section (223) in a reinforcing member (22). Thus, when a sound absorbing cover member (2) is fastened with bolts (3) via the reinforcing member (22), the second bolt fastening section (222), which is one bolt fastening section, is fastened with a bolt (3) during a condition in which a bolt (3) has been provisionally inserted and provisionally fixed in the first bolt fastening section (221), which is the other bolt fastening section, whereby it is possible to suppress co-rotation of the reinforcing member (22) that accompanies the fastening. Consequently, damage to the sound-absorbing cover member (2) that accompanies the fastening of the bolts (3) can be suppressed.

Description

Sound-absorbing cover structure

[0001] The present invention relates to a sound-absorbing cover structure.

[0002] As a conventional sound-absorbing cover structure, for example, the one described in Patent Document 1 below is known.

[0003] In the conventional sound-absorbing cover structure, a cover body made of a sound-absorbing material capable of absorbing the vibration of an internal combustion engine and a reinforcing body provided inside the cover body for reinforcing the cover body are integrally insert-molded. Also, in the conventional sound-absorbing cover structure, a cylindrical reinforcing member is integrally insert-molded with a cover member separately from the reinforcing body, thereby forming a bolt fastening portion for fixing the sound-absorbing cover member to the internal combustion engine.

[0004] However, in the conventional sound-absorbing cover structure, in addition to the fact that a reinforcing member is provided separately from the reinforcing body and the structure is complicated, the reinforcing body and the reinforcing member are only integrated by the cover body and are not fixed to each other. For this reason, when the sound-absorbing cover member is bolt-fastened, there is still room for improvement in that the reinforcing member may rotate and the cover body integrated by insert molding may be twisted and damaged.

[0005] Japanese Unexamined Patent Application Publication No. 2023-054574

[0006] In one aspect of the present invention, there is provided a sound-absorbing cover structure in which a sound-absorbing cover member is fastened to an outer surface of a housing by a plurality of bolts. The sound-absorbing cover member includes a cover body formed of a sound-absorbing material and having a first opening and a second opening for avoiding the heads of the respective bolts, a first bolt fastening portion provided integrally with the sound-absorbing cover member inside the cover body by insert molding and exposed to the outside from the first opening, a second bolt fastening portion exposed to the outside from the second opening, and a connecting portion connecting the first bolt fastening portion and the second bolt fastening portion, and a reinforcing member integrally having these.

[0007] According to the present invention, in the reinforcing member, the first bolt fastening portion and the second bolt fastening portion are connected by a connecting portion. Therefore, when bolting the sound-absorbing cover member via the reinforcing member, by temporarily inserting and securing the bolt in one bolt fastening portion and then bolting the other bolt fastening portion, it is possible to suppress the rotation of the reinforcing member that occurs during the fastening. This makes it possible to suppress damage to the sound-absorbing cover member that occurs during bolt fastening.

[0008] Furthermore, in the reinforcing member, the first bolt fastening portion and the second bolt fastening portion are exposed from the cover body, making it possible to use each bolt fastening portion as a bolt seating surface when fastening the bolts. As a result, the sound-absorbing cover member is firmly fixed, and loosening of the bolt fastening portions due to vibration can be suppressed.

[0009] This is a perspective view of an internal combustion engine to which the sound-absorbing cover structure according to the present invention is applied. Figure 1 is a plan view of the sound-absorbing cover member shown. Figure 2 is a plan view of the reinforcing member shown.

[0010] The following describes in detail an embodiment of the sound-absorbing cover structure according to the present invention with reference to the drawings. In this embodiment, as with the conventional example, an example is given in which the sound-absorbing cover structure is applied to the cylinder block 1 of an automobile engine (spark-ignition internal combustion engine).

[0011] (Cylinder Block Configuration) Figure 1 shows a perspective view of the cylinder block 1 of an internal combustion engine to which the sound-absorbing cover structure according to this embodiment is applied, viewed from the front and diagonally above.

[0012] As shown in Figure 1, the cylinder block 1 is formed by casting a metal such as aluminum alloy or cast iron, and integrally comprises a cylinder portion 11 in which a piston (not shown) is slidably housed, and a crankcase portion 12 provided below the cylinder portion 11 in which the upper half of a crankshaft (not shown) is rotatably housed.

[0013] The cylinder section 11 has a plurality of cylinders 13 (for example, three in this embodiment) arranged in series in the front-to-back direction. The crankcase section 12 has a so-called half-skirt structure, and a plurality of bearing sections 14 capable of supporting the upper half (upper half-circumference) of the crankshaft (not shown) are provided along the cylinder row direction, which is the axial direction of the crankshaft (not shown).

[0014] Furthermore, a recessed cover mounting portion 15, which is recessed in a stepped manner, is provided on the outer surface of the cylinder block 1. A sound-absorbing cover member 2, which suppresses vibration (sound vibration) of the cylinder block 1, is fitted into the cover mounting portion 15. The sound-absorbing cover member 2 is fixed by a plurality of bolts 3, which are screwed into female screw holes (not shown) formed in a plurality of boss portions (not shown) provided on the cover mounting portion 15.

[0015] In this embodiment, the cover mounting portion 15 is shown, as an example, as having a rectangular shape in plan view and a flat garden wall 150. However, the cover mounting portion 15 can be arbitrarily changed depending on the shape of the housing (cylinder block 1 in this embodiment) to which the sound-absorbing cover member 2 is attached, and the mounting range of the sound-absorbing cover member 2. In other words, the cover mounting portion 15 may be formed in an irregular shape in plan view, and the garden wall 150 may have irregularities.

[0016] (Configuration of sound-absorbing cover member) Figure 2 shows a plan view of the sound-absorbing cover member 2 shown in Figure 1. Figure 3 shows a plan view of the reinforcing member 22 shown in Figure 2.

[0017] As shown in Figure 2, the sound-absorbing cover member 2 integrally comprises a cover body 21 formed in a generally plate-like shape from a sound-absorbing material such as urethane, and a metal reinforcing member 22 embedded inside the cover body 21 by insert molding. In other words, the portion of the sound-absorbing cover member 2 that is fastened by each bolt 3 (the first bolt fastening portion 221 and the second bolt fastening portion 222, which will be described later) is made up of the reinforcing member 22, and the majority of the reinforcing member 22 is embedded in the cover body 21, except for the respective bolt fastening portions 221 and 222.

[0018] The cover body 21 is shaped to fit into the cover mounting portion 15, and in this embodiment, it is formed in the shape of a rectangular plate. That is, the cover body 21 has a planar shape and thickness that correspond to (match) the planar shape and depth shape of the cover mounting portion 15, and is configured to be able to generally fit tightly against the side surface of the cover mounting portion 15 that faces the cover body 21. In other words, the cover body 21 is not limited to a rectangular plate shape and can be arbitrarily changed according to the shape of the cover mounting portion 15.

[0019] Furthermore, the cover body 21 has multiple openings, for example, a first opening 211 and a second opening 212, which are provided in positions that overlap with each of the boss portions (not shown) in a plan view, so as to avoid the heads 30 of the bolts 3, and these openings are formed to penetrate through the cover body 21 in the thickness direction. In addition to the first opening 211 and the second opening 212 used for fixing the sound-absorbing cover member 2, the cover body 21 may also have other openings, such as those in the cylinder block 1, to avoid auxiliary components such as hydraulic sensors and knock sensors.

[0020] The first opening 211 and the second opening 212 are each formed in a generally circular shape. The first opening 211 and the second opening 212 have an opening size that exposes almost the entirety of the first bolt fastening portion 221 and the second bolt fastening portion 222, which will be described later, to the outside. That is, the inner diameters D11 and D12 of the first opening 211 and the second opening 212 are set to be larger than the head 30 of each bolt 3, and to be equal to or larger than the outer diameters D21 and D22 of the first bolt fastening portion 221 and the second bolt fastening portion 222, which will be described later.

[0021] Furthermore, the inner diameters D11 and D12 of the first opening 211 and the second opening 212 are set to be larger than the outer diameter of a tool (socket wrench) not shown that is fitted onto the head 30 of each bolt 3 when the bolts 3 are fastened. In other words, the openings of the first opening 211 and the second opening 212 are set to an amount that does not interfere with the tool (socket wrench) not shown that is fitted onto the head 30 of each bolt 3, thereby suppressing the rotation of the cover body 21 that occurs when the tool (socket wrench) rotates.

[0022] The reinforcing member 22 is formed by punching out a metal plate using a press, and as shown in Figure 3, it integrally has a plurality of bolt fastening parts formed in a generally annular shape, for example, a first bolt fastening part 221 and a second bolt fastening part 222 in this embodiment, and a connecting part 223 that connects the first bolt fastening part 221 and the second bolt fastening part 222. In the sound-absorbing cover member 2, only the first bolt fastening part 221 and the second bolt fastening part 222 of this reinforcing member 22 are exposed to the outside through the first opening 211 and the second opening 212, while the connecting part 223 is embedded in the cover body 21.

[0023] The first bolt fastening portion 221 and the second bolt fastening portion 222 have an outer diameter larger than the head 30 of the bolt 3 (including a washer, not shown), and each has a through-hole 220 formed in the center through which the shaft portion (not shown) of the bolt 3 can be inserted. Each bolt through-hole 220 is set to have an inner diameter larger than the outer diameter of the shaft portion (not shown) of the bolt 3 and smaller than the head 30 of the bolt 3 (including a washer, not shown). In this way, the first bolt fastening portion 221 and the second bolt fastening portion 222 constitute a bolt seating surface on which the head 30 of the bolt 3 (including a washer, not shown) is seated.

[0024] The connecting portion 223 is formed as a flat plate with a constant thickness that is generally continuous with the first bolt fastening portion 221 and the second bolt fastening portion 222 without any steps. Furthermore, the connecting portion 223 has a constant width W that is smaller than the outer diameters D21 and D22 of the first bolt fastening portion 221 and the second bolt fastening portion 222, and is formed in a bent shape that is generally crank-shaped when viewed from above.

[0025] The connecting portion 223 may be formed so that its width W expands or contracts in the longitudinal direction. In this case, the maximum value of the width W of the connecting portion 223 is set to be smaller than the outer diameters D21 and D22 of the first bolt fastening portion 221 and the second bolt fastening portion 222, thereby reducing the weight of the sound-absorbing cover member 2. Furthermore, the connecting portion 223 is not limited to the bent shape described above, but may be formed in a straight shape that linearly connects the first bolt fastening portion 221 and the second bolt fastening portion 222. In other words, the shape of the connecting portion 223 can be arbitrarily changed according to the shape and specifications of the sound-absorbing cover member 2.

[0026] (Effects of this embodiment) As described above, in the sound-absorbing cover structure according to this embodiment, the first bolt fastening portion 221 and the second bolt fastening portion 222 of the reinforcing member 22 are connected by a connecting portion 223. Therefore, when fastening the sound-absorbing cover member 2 with bolts 3 via the reinforcing member 22, by temporarily inserting and temporarily fastening the bolt 3 into one bolt fastening portion (for example, the first bolt fastening portion 221) and then fastening the other bolt fastening portion (the second bolt fastening portion 222) with the bolt 3, it is possible to suppress the rotation of the reinforcing member 22 that occurs when fastening. This makes it possible to suppress damage to the sound-absorbing cover member 2 that occurs when fastening the bolts 3.

[0027] In addition, in the reinforcing member 22, the first bolt fastening portion 221 and the second bolt fastening portion 222 are exposed from the cover body 21, making it possible to use each bolt fastening portion 221 and 222 as a bolt seating surface when fastening bolts. As a result, the sound-absorbing cover member 2 is firmly fixed, and loosening of each bolt fastening portion 221 and 222 due to vibration can be suppressed.

[0028] Furthermore, in this embodiment, the connecting portion 223, which is the part of the reinforcing member 22 excluding the first bolt fastening portion 221 and the second bolt fastening portion 222, is covered by the cover body 21. Therefore, the vibration of the connecting portion 223, which forms the skeleton of the reinforcing member 22, can be absorbed by the cover body 21. As a result, the amplification of vibrations caused by the reinforcing member 22 can be suppressed in the sound-absorbing cover member 2.

[0029] Furthermore, since most of the reinforcing member 22, excluding the first bolt fastening portion 221 and the second bolt fastening portion 222, is covered by the cover body 21, damage to other parts and other components placed around the cylinder block 1 when they come into contact with the sound-absorbing cover member 2 can be suppressed.

[0030] Furthermore, in this embodiment, the reinforcing member 22 is formed in a generally flat plate shape. This improves the productivity of the reinforcing member 22 and facilitates insert molding of the reinforcing member 22 into the sound-absorbing cover member 2. As a result, the productivity of the sound-absorbing cover member 2 can be improved and manufacturing costs can be reduced.

[0031] Furthermore, in this embodiment, the connecting portion 223 of the reinforcing member 22 is formed in a curved shape, which is not linear in plan view. Therefore, compared to the case where the connecting portion 223 is formed in a linear shape, it is possible to give the connecting portion 223 a wider surface area. As a result, the sound-absorbing cover member 2 is effectively reinforced and the shape of the sound-absorbing cover member 2 can be stably maintained.

[0032] Furthermore, the connecting portion 223 is formed to a constant width W, which improves productivity. Also, by setting the width W to be smaller than the outer diameters D21 and D22 of the first bolt fastening portion 221 and the second bolt fastening portion 222, the reinforcing member 22 is made lighter, and consequently the sound-absorbing cover member 2 is made lighter.

[0033] The present invention is not limited to the configurations illustrated in the above embodiments, and can be freely modified according to, for example, the specifications of the housing to which the sound-absorbing cover structure according to the present invention is applied.

[0034] In the above embodiment, the sound-absorbing cover structure according to the present invention was illustrated by applying it to the cylinder block 1 of an engine. However, the sound-absorbing cover member 2 can be applied to any housing that is subject to vibration, such as the casing of a motor, in addition to the engine cylinder block 1.

Claims

1. A sound-absorbing cover structure in which a sound-absorbing cover member is fastened to the outer surface of a housing by a plurality of bolts, wherein the sound-absorbing cover member comprises: a cover body formed of a sound-absorbing material and having a first opening and a second opening to avoid the heads of each bolt; and a reinforcing member integrally provided inside the cover body by insert molding with the sound-absorbing cover member and having a first bolt fastening portion exposed to the outside from the first opening, a second bolt fastening portion exposed to the outside from the second opening, and a connecting portion connecting the first bolt fastening portion and the second bolt fastening portion.

2. A sound-absorbing cover structure according to claim 1, wherein the reinforcing member is covered by the cover body, except for the first bolt fastening portion and the second bolt fastening portion.

3. The sound-absorbing cover structure according to claim 2, wherein the reinforcing member is formed in the shape of a flat plate.

4. The sound-absorbing cover structure according to claim 3, wherein the connecting portion is formed in a curved shape in a plan view.

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