JP5831281B2 - Noise suppression cover - Google Patents

Description

  The present invention belongs to a technical field related to a noise suppression cover that is bolted to an outer surface of an engine using screw holes formed on the outer surface of an engine mounted on a vehicle.

  2. Description of the Related Art Conventionally, there has been known one in which an outer surface of an engine mounted on a vehicle is covered with a noise suppression cover (see, for example, Patent Document 1). This noise suppression cover is formed by press-molding a sheet sandwiching a sound absorbing material or a sound insulating material, and is fixed to the outer surface of the engine with a bolt.

JP 2009-236091 A

  Here, in order to enhance the noise suppression effect by the noise suppression cover, it is preferable to integrate the sound absorbing cover member and the sound insulating cover member.

  However, recent vehicles tend to reduce the space around the engine in the engine room in order to improve indoor comfort and collision safety. For this reason, for example, a sound absorbing cover member and a sound insulating cover member are integrated. In this case, there is a problem that the detachability of the noise suppression cover is remarkably deteriorated due to the combined increase in the thickness of the noise suppression cover and the reduction in the space around the engine.

  In particular, in order to improve the sound absorbing performance of the sound absorbing cover member, in the noise suppression cover in which the surface shape of the sound absorbing cover member is made to correspond to the uneven shape of the outer surface of the engine, the surface shape of the sound absorbing cover member is complicated, The problem of deterioration of the attachment / detachment property becomes remarkable.

  Therefore, after the sound absorbing cover member and the sound insulating cover member are separated and attached to the engine separately so that the noise suppression cover can be easily attached and detached even in a narrow space in the engine room, both cover members are attached. Can be fixed together with bolts. A stepped bolt may be used for this bolt in order to prevent excessive tightening.

  However, in this case, since the bolt insertion hole of the sound absorbing cover member located on the engine side is hidden by the sound insulating cover member located on the outer side of the engine, the position of the bolt insertion hole of the sound insulating cover member and the sound absorbing cover member during assembly work The position of the bolt insertion hole is easily shifted. As a result, the bolt step (large-diameter shaft portion) is caught around the bolt insertion hole of the sound absorbing cover member, resulting in poor engagement, and the sound absorbing material of the sound absorbing cover member is compressed more than necessary. There is a problem that is damaged.

  The present invention has been made in view of such a point, and the object of the present invention is to devise a configuration for a bolt-fixed noise suppression cover having both a sound absorbing function and a sound insulating function. By stiffening, it is intended to surely prevent the occurrence of a poor bolt engagement when the noise suppression cover is assembled to the engine.

  Specifically, the first invention is directed to a noise suppression cover that is bolted to the outer surface of the engine using screw holes formed on the outer surface of the engine mounted on the vehicle.

  The sound absorbing cover member that is mounted on the outer surface of the engine and absorbs engine sound is separated from the sound absorbing cover member, and is disposed so as to overlap the outer surface of the sound absorbing cover member. A sound insulation cover member that blocks sound, and the bolt has a large diameter shaft portion, a small diameter shaft portion that protrudes from one end surface of the large diameter shaft portion in the bolt shaft direction and has a male screw formed on the outer peripheral portion. And the sound-insulating cover member and the sound-absorbing cover member each have a bolt insertion hole having a hole diameter corresponding to the large-diameter shaft portion of the bolt, and the sound-absorbing cover. On the surface of the member on the engine side, a protrusion is formed that protrudes toward the engine and the tip is in contact with the outer surface of the engine. The protrusion is only part of the small-diameter shaft portion of the bolt. In the hole And the projection height is set so that the bolt insertion hole of the sound absorbing cover member is located at the large-diameter shaft portion of the bolt in a temporarily tightened state where the compression load by the bolt does not act on the projection. In the final tightening state in which the entire small-diameter shaft portion of the bolt is screwed into the screw hole, the bolt is configured to be compressed or deformed in the bolt shaft direction or to be sunk in the sound absorbing cover member. It has been done.

  In the first invention, when the positional relationship between the position of the bolt insertion hole of the sound absorption cover member and the position of the bolt insertion hole of the sound insulation cover member is normal (coaxial), the sound absorption cover member is temporarily tightened. The portion of the sound absorbing cover member excluding the protrusion is separated from the engine outer surface to the engine outer side by the height of the protrusion, and the bolt insertion hole of the sound absorbing cover member is positioned at the large diameter shaft portion of the bolt. Can be made. As a result, since the large-diameter shaft portion of the bolt is inserted into the bolt insertion hole of the sound absorbing cover member in the temporarily tightened state before starting the bolt final tightening, during the subsequent final tightening operation, The large diameter shaft portion is not caught around the bolt insertion hole of the sound absorbing cover member.

  On the other hand, in the final tightening state of the bolt, the projecting portion receives a compressive load from the bolt and is in a state of being compressed and deformed in the bolt axial direction or sinking into the sound absorbing cover member. However, it approaches to the preset separation distance with respect to the engine outer surface.

  Here, when the positional relationship between the bolt insertion hole of the sound absorption cover member and the bolt insertion hole of the sound insulation cover member is shifted, the large diameter shaft portion of the bolt is inserted into the sound absorption cover member when the bolt is inserted into both bolt insertion holes. It will get caught around the bolt insertion hole. When this happens, the tip of the bolt does not reach the screw hole, or even if it reaches the screw hole, it will not be screwed in sufficiently, so the operator will unintentionally push the bolt in the axial direction and try to tighten it. As a result, the protrusion receives a compressive load from the bolt and is compressed and deformed. Therefore, the operator feels the reaction force accompanying the compressive deformation (or sinking) of the protrusion, which should be felt only during the final tightening operation, even during the temporary tightening operation. Therefore, it can be determined that a poor biting of the bolt has occurred.

  According to a second invention, in the first invention, the engine-side surface of the sound absorbing cover member has an uneven shape corresponding to the unevenness of the engine outer surface.

  In the second invention, since the outer surface of the sound absorbing cover member has a complicated uneven shape corresponding to the unevenness of the engine outer surface, a large gap is formed between the engine outer surface and the surface of the sound absorbing cover member facing it. The sound absorbing performance of the sound absorbing cover member can be enhanced as much as possible without the sound being leaked and the sound leaking from the gap.

  Thus, if the engine-side surface of the sound-absorbing cover member has a concavo-convex shape, when the noise suppression cover is assembled to the engine, this concavo-convex interferes with engine accessories and sensors. Workability deteriorates. As a result, it is difficult to adjust the position of the sound absorbing cover member, and the above-described problem of displacement of the bolt insertion hole is likely to occur. The present invention is particularly useful for a noise suppression cover having such a configuration because the sound absorbing cover member can be moved in parallel by moving it alone even in a relatively narrow space, and the assembling work can be facilitated.

  According to a third invention, in the first or second invention, the protrusion is provided around the bolt insertion hole in the engine-side surface of the sound absorbing cover member.

  In 3rd invention, the position of a volt | bolt can be closely approached with respect to the said projection part as much as possible at the time of the temporary fastening operation | work of a volt | bolt. Therefore, the reaction force accompanying the compression deformation (or sinking) of the protrusion can be sufficiently transmitted to the operator's hand through the bolt. Therefore, the same effect as that of the invention of claim 1 can be obtained more reliably.

  According to a fourth invention, in any one of the first to third inventions, the sound absorbing cover member has a sound absorbing material made of a foamed resin body, and the protruding portion is integrated with the sound absorbing material of the sound absorbing cover member. It is what has been molded.

  In the fourth invention, since the sound absorbing material and the projecting portion of the sound absorbing cover member are both made of the same kind of member, compared to the case where the sound absorbing material and the projecting portion are made of different materials, both of the bolt axial directions The difference in rigidity can be reduced. As a result, when the compressive load by the bolt acts on the protrusion, the protrusion does not sink into the sound absorbing material but compressively deforms. Thereby, in the final tightening state of the bolt, it is possible to suppress the deformation of the portion of the sound absorbing material excluding the protruding portion (hereinafter referred to as the sound absorbing main body portion) as much as possible. Since the sound absorbing main body portion has a greater influence on the sound absorbing performance than the protrusions, it is possible to suppress a decrease in the sound absorbing performance by suppressing the deformation of the sound absorbing main body portion.

  Further, since the protrusion is integrally formed with the sound absorbing material of the sound absorbing cover member, the number of parts can be reduced and the cost can be reduced.

  According to a fifth invention, in the fourth invention, the sound absorbing cover member further includes a shape holding plate for holding the shape of the sound absorbing material joined to the outer surface of the sound absorbing material, and the sound absorbing cover. The bolt insertion hole of the member is constituted by a through hole formed in the shape holding plate.

  In the fifth invention, since the shape holding plate is joined to the outer surface of the sound absorbing material, it is possible to suppress the shape deformation of the sound absorbing material and maintain the desired sound absorbing performance for a long period of time. it can.

  According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the engine has a crankshaft disposed between a pair of left and right front side frames extending in the front-rear direction at a vehicle body front portion of the vehicle. The sound-absorbing cover member and the sound-insulating cover member are disposed so as to overlap the front side frame when viewed from the vehicle width direction.

  In the sixth invention, the sound absorbing cover member and the sound insulating cover member constituting the noise suppression cover are disposed so as to overlap the front side frame when viewed from the vehicle width direction. For this reason, it is necessary to attach and detach the noise suppression cover in a narrow space between the front side frame and the engine, and there is a problem that workability is poor.

  On the other hand, in the present invention, the sound absorbing cover member and the sound insulating cover member are separated and each cover member is separately attached to the engine so that the cover can be attached and detached even in such a narrow space. Work can be done easily. In the case where the sound absorbing cover member and the sound insulating cover member are separated from each other in this way, when the cover members are attached to the outer surface of the engine, the positions of the bolt insertion holes of both the members are easily shifted. The configuration is particularly useful.

  As described above, according to the noise suppression cover of the present invention, the noise suppression cover is constituted by the sound absorbing cover member and the sound insulating cover member that are separate from each other, and the bolt shaft is mounted on the engine side surface of the sound absorbing cover member. In a state where a projecting portion that is compressively deformable in the direction is formed and the bolt is temporarily tightened, the sound absorbing cover member is separated from the outer surface of the engine toward the outer side of the engine by the height of the projecting portion. Since the large-diameter shaft portion of the bolt is inserted into the bolt insertion hole of the cover member, the noise suppression cover can be installed without causing the bolt biting failure even in a narrow space in the engine room. Can be easily assembled to the engine outer surface.

It is the side view seen from the right side of the vehicle width direction which shows the horizontal engine with which the noise suppression cover concerning an embodiment of the present invention was equipped. It is the top view seen from the upper side which shows the vehicle width direction right side part of the engine with which the noise suppression cover was mounted | worn. Couplers for O ₂ sensor harness is an enlarged view showing a portion provided in Figure 1. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. It is the top view seen from the back side (engine side) which shows a front side sound absorption cover member, (b) is a perspective view. It is the top view seen from the back side (engine side) which shows a rear side sound absorption cover member, and (b) is a perspective view. It is the VII-VII sectional view taken on the line of FIG. It is the top view seen from the front side (engine outer side) which shows a front side sound-insulation cover member. It is the top view seen from the front side (engine outer side) which shows a rear side sound-insulation cover member. FIG. 10 is a sectional view taken along line XX in FIG. 9. It is a figure corresponded to the XI-XI sectional view taken on the line of FIG. 1 which shows the state in which the bolt occlusion failure has arisen.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 show an engine 2 equipped with a noise suppression cover 1 according to an embodiment of the present invention. In the following description, “front side” and “rear side” mean the front side and the rear side of the vehicle, and “left side” and “right side” mean the left side and the right side toward the front side of the vehicle. .

  The engine 2 is a so-called horizontal engine in which the crankshaft 3 is arranged so as to face the vehicle width direction, and is housed in an engine room in the front part of the vehicle. A front side frame 4 that extends horizontally in the front-rear direction and forms a skeleton of the front portion of the vehicle body is disposed on each of the left and right sides of the engine 2. That is, the engine 2 is disposed so as to fit between the pair of left and right front side frames 4. A narrow gap space 5 (see FIG. 2) is formed between the engine 2 and the front side frame 4 so that a hand can just enter.

  The right side surface of the engine 2 is covered with a chain case 6 that forms the outer surface of the engine. In the present embodiment, the outer surface of the chain case 6 is suppressed in order to suppress noise (engine sound) caused by the meshing sound between the chain and the sprocket in the chain case 6 from being transmitted to the passengers inside the room and the outside of the vehicle. The cover 1 covers the area.

  The noise suppression cover 1 includes a front noise suppression cover 1f and a rear noise suppression cover 1r. Each noise suppression cover 1f, 1r is disposed between the chain case 6 of the engine 2 and the front side frame 4. Each noise suppression cover 1f, 1r is disposed so as to overlap the front side frame 4 when viewed from the vehicle width direction (see FIG. 1).

As shown in FIG. 3, a coupler bracket 8 for fixing the coupler 7 is fixed with bolts 12 at the center in the vertical direction on the right side surface of the engine and on the rear side of the rear noise suppression cover 1r. ing. This coupler 7 is for connecting the O ₂ sensor harness 9.

  On the outer surface of the chain case 6 of the engine 2 (engine outer surface), there are five boss portions 11 (one of which is shown in FIG. 4) forming the mounting seat surface 10 of the front and rear noise suppression covers 1f and 1r. Is shown). A top surface of each boss portion 11 forms a mounting seat surface 10, and a screw hole 13 is formed in the seat surface 10. The noise suppression covers 1f and 1r are fixed to the outer surface of the chain case 6 with bolts 14 using these screw holes 13.

  Here, if the bolts 14 are excessively tightened when the noise suppression covers 1f and 1r are fixed with the bolts 14, the shapes of the noise suppression covers 1f and 1r (particularly the shape of the sound absorbing material 23) are deformed. As a result, the desired noise suppression effect may not be obtained. Therefore, such excessive tightening is prevented by configuring the bolt 14 with a stepped bolt.

  Specifically, as shown in FIG. 4, the bolt 14 includes a large-diameter shaft portion 15, a small-diameter shaft portion 16 projecting from one end surface of the large-diameter shaft portion 15 in the bolt shaft direction, and the large-diameter shaft portion 15. It has a dish-shaped washer portion 17 and a bolt head portion 18 formed on the other end surface. As a result, when the bolt 14 is tightened by a predetermined amount or more, the bolt step surface located at the boundary between the large diameter shaft portion 15 and the small diameter shaft portion 16 contacts the top surface (mounting seat surface 10) of the boss portion 11. The tightening of the bolt 14 is regulated in contact. Thus, excessive tightening of the bolt 14 can be prevented. In this embodiment, the bolt 14 is a washer-integrated bolt. However, the present invention is not limited to this, and the washer portion 17 may be formed separately from the bolt 14.

  The noise suppression covers 1f and 1r are separate from the sound absorbing cover member 21 and the sound absorbing cover member 21 that are directly attached to the outer surface of the engine (the outer surface of the chain case). And a sound insulation cover member 22 arranged on the surface. The sound absorbing cover member 21 has a function of absorbing (attenuating) engine sound (in this embodiment, in particular, engagement sound between the chain and the sprocket), and the sound insulating cover member 22 blocks engine sound and leaks to the outside. It has the function to prevent. The sound absorbing cover member 21 is formed thicker than the sound insulating cover member 22.

  5 and 6 show front and rear sound absorbing cover members 21f and 21r used for the front and rear noise suppression covers 1f and 1r, respectively. Each of the sound absorbing cover members 21f and 21r includes a sound absorbing material 23 made of a foamed resin body (urethane in the present embodiment), and a shape holding plate 24 that is bonded to the surface of the sound absorbing material 23 on the engine outer side and holds its planar shape. (See FIG. 7). The shape retaining plate 24 is made of a plate material made of resin (PA66 in this embodiment). The shape retaining plate 24 is formed with a bolt insertion hole 25 through which the fixing bolt 14 is inserted. Each bolt insertion hole 25 penetrates the shape retaining plate 24 in the thickness direction. In the present embodiment, three bolt insertion holes 25 are formed in the shape retaining plate 24 of the front sound absorbing cover member 21f (see FIG. 5), and two bolt insertion holes are formed in the shape retaining plate 24 of the rear sound absorbing cover member 21r. 25 is formed (see FIG. 6). The diameter of each bolt insertion hole 25 is set to a diameter corresponding to the diameter of the large-diameter shaft portion 15 of the bolt 14 (slightly larger than the large-diameter shaft portion 15 of the bolt 14). The annular portion surrounding the periphery of the bolt insertion hole 25 in each shape holding plate 24 is not joined to the sound absorbing material 23 and is in the form of a single plate. And the annular part which makes this single plate shape forms the seat surface part 31 contact | abutted to the top face of the boss | hub part 11 of the said engine 2. As shown in FIG.

  The engine-side surface of the sound absorbing material 23 has an uneven shape corresponding to the uneven shape of the engine outer surface (the outer surface of the chain case 6). Further, on the surface of the sound absorbing material 23 on the engine side, apart from the uneven shape corresponding to the engine shape, a protruding portion 33 is formed which protrudes toward the engine side and the tip portion abuts against the outer surface of the engine. . Specifically, as shown in FIG. 5, the engine-side surface of the sound-absorbing material 23 of the front-side sound-absorbing cover member 21f has an upper protrusion 33a having a vertically long rectangular shape when viewed from the back side in the mounting posture, and a triangular shape. A lower protrusion 33b formed and an intermediate protrusion 33c having a horizontally long rectangular shape are formed. As shown in FIG. 6, the engine-side surface of the sound-absorbing material 23 of the rear-side sound-absorbing cover member 21r has a substantially rectangular shape with an upper protrusion 33d that is substantially L-shaped when viewed from the back side in the mounting posture. A lower protrusion 33e is formed. Each of the protrusions 33 a to 33 e is disposed in the vicinity of the seat surface portion 31 formed on the shape retaining plate 24 (also referred to as the vicinity of the bolt insertion hole 25).

  Since the protrusion 33 is made of a foamed resin body (urethane), the protrusion 33 has elasticity, and the elasticity enables compression deformation in the protrusion height direction. That is, for example, the height of the lower projection 33e provided on the sound absorbing material 23 of the rear noise suppression cover 1r is equal to the initial height H (in the state where no compressive load is applied to the projection 33e) (see FIG. 4 (a)), in the final tightening state in which the final tightening of the bolt 14 is completed and the compressive load in the bolt axial direction is applied to the projection 33e, the compression height is smaller than the initial height H. It decreases to h (<H) (see FIG. 4B).

  The protrusion 33 is formed on the shape retaining plate 24 by separating the sound absorbing cover member 21 (shape retaining plate 24) from the outer surface of the engine by the initial height H in the temporarily tightened state of the bolt 14. The bolt insertion hole 25 is configured to be positioned on the large diameter shaft portion 15 of the bolt 14 (in other words, the large diameter shaft portion 15 of the bolt 14 is inserted into the bolt insertion hole 25 of the sound absorbing cover member 21. (See FIG. 4A).

  8 and 9 show front and rear sound insulation cover members 22f and 22r used for the front and rear noise suppression covers 1f and 1r, respectively. As shown in FIG. 10, each of the sound insulation cover members 22f and 22r has a four-layer structure in which a melamine foam material 27 and a cotton felt 28 are sandwiched between two nonwoven fabrics 30 (FIG. 10 shows a rear sound insulation cover). Only the cross-sectional structure of the member 22r is shown). Bolt insertion holes 26 are formed in the sound insulation cover members 22 f and 22 r at positions corresponding to the screw holes 13 of the engine 2. The hole diameter of the bolt insertion hole 26 is set to a diameter corresponding to the diameter of the large-diameter shaft portion 15 of the bolt 14 (slightly larger than the large-diameter shaft portion 15 of the bolt 14). The peripheral portion of the bolt insertion hole 26 in each of the sound insulation cover members 22f and 22r has a single layer structure of only the nonwoven fabric 30, and the annular portion surrounding the periphery of the bolt insertion hole 26 forms the seating surface 32 of the washer portion 17 of the bolt 14. doing.

  The sound absorbing cover members 21f and 21r and the sound insulating cover members 22f and 22r are assembled to the engine 2 in a state where the bolt insertion holes 25 and 26 formed in the respective shafts are coaxial with each other.

By the way, when exchanging the O ₂ sensor harness 9, it is necessary to perform the exchanging work from below the engine room. In this case, in order to secure a working space, the lower part of the rear noise suppression cover 1r is required. Get in the way. Therefore, when the O ₂ sensor harness 9 is replaced, it is necessary to perform the work of removing the rear side noise suppression cover 1r on the vehicle.

  The operation of attaching / detaching the noise suppression cover 1 to / from the engine 2 on the vehicle will be described with reference to FIGS. 1, 2, and 4. Each figure shows a state in which the front and rear noise suppression covers 1f and 1r are attached to the engine 2 (FIG. 4A is a temporarily fixed state).

First, the bolts 14 and 14 that fasten the rear noise suppression cover 1r are loosened and removed from the upper and lower sides of the engine room using a wrench, and the rear sound insulation cover member 22r is attached to the front side frame 4 side. It removes from the space 5, and removes the back side sound absorption cover member 21r similarly. Thereafter, the O ₂ sensor harness 9 is removed and replaced using a work space extending from below the engine room. After the O ₂ sensor harness 9 is replaced, the rear sound absorbing cover member 21r and the rear sound insulating cover member 22r are attached.

  First, after moving the sound absorbing material 23 of the rear sound absorbing cover member 21r in parallel using the work space that spreads from the lower side of the engine room, the surface of the sound absorbing material 23 has unevenness toward the engine side. Arrange it so that it enters the unevenness of the outer surface of the engine. Then, the position of the bolt insertion hole 25 of the rear side sound absorbing cover member 21r (shape holding plate 24) is adjusted to the position of the screw hole 13 of the engine 2 by finely adjusting the position of the rear side sound absorbing cover member 21r. After the position adjustment of the rear side sound absorbing cover member 21r is completed, the rear side sound absorbing cover member 22r is moved in parallel from between the rear side sound absorbing cover member 21r and the front side frame 4, and then the rear side sound absorbing cover member 21r is moved. The cover member 21r is arranged so as to overlap the outer surface of the engine. Then, by finely adjusting the position of the rear side sound insulation cover member 22r, the position of the bolt insertion hole 26 is adjusted to the position of the bolt insertion hole 25 of the rear side sound absorption cover member 21r (both bolt insertion holes 25 and 26 are coaxial. To set). At this time, the positioning of the bolt insertion holes 25 and 26 cannot be visually observed due to the presence of the front side frame 4, and is a sensuous work. Then, after the position adjustment of the rear sound insulating cover member 22r is completed, the bolt 14 is tightened.

  This bolt tightening operation is roughly divided into two operations, a temporary tightening operation and a main tightening operation. In the temporary fastening operation, the rear side sound absorbing cover member 21r and the rear side sound insulating cover member 22r are temporarily fixed with bolts 14 and 14 so as not to drop off from the outer surface of the engine (see FIG. 4A). Specifically, first, as an operation from the upper side and the lower side of the engine room, the upper and lower bolts 14 are inserted into the bolt insertion holes 25 and 26 from the engine outer side while visual confirmation is difficult. And when the front-end | tip part of the volt | bolt 14 reaches the screw hole 13, it tightens, rotating the volt | bolt 14 with a finger | toe. Then, when several peaks (for example, about 3 to 5 peaks) of the tip end portion of the small-diameter shaft portion 16 of the bolt 14 are screwed into the screw hole 13, the tightening of the bolt 14 is finished. Thus, the temporary tightening operation of the bolt 14 is completed. In the present embodiment, in a state where the bolts 14 are temporarily tightened (hereinafter referred to as a temporary tightening state), the seat surface of the plate-shaped washer portion 17 of the bolt 14 is in contact with the seating surface 32 of the rear sound-insulating cover member 22r. .

  The purpose of temporarily tightening the bolt 14 is to temporarily fix the cover members 21r and 22r to the outer surface of the engine. Therefore, in the temporarily tightened state, the bolt 14 is bolted to the protruding portion 33 of the rear sound absorbing cover member 21r. 14 hardly acts, and the height of the protrusion 33 in the temporarily tightened state remains the initial height H.

  Therefore, the rear sound absorbing cover member 21r is separated from the engine outer surface to the engine outer side by the initial height H of the protrusion 33 (the protrusion height) in the temporarily tightened state of the bolt 14, and as a result, The bolt insertion hole 25 of the rear side sound absorbing cover member 21r is positioned in the large diameter shaft portion 15 of the bolt 14. In other words, in the temporarily tightened state, the large-diameter shaft portion 15 of the bolt 14 is inserted into the bolt insertion hole 25.

  Then, after the temporary tightening of the bolt 14 is completed, a final tightening operation of the bolt 14 is started using a tool such as an impact wrench. At this time, since the large-diameter shaft portion 15 of the bolt 14 is already inserted into the bolt insertion hole 25, even if the position of the rear-side sound absorbing cover member 21r is slightly shifted during the final tightening operation, the bolt 14 The large-diameter shaft portion 15 is not caught around the bolt insertion hole 25 of the rear side sound absorbing cover member 21r.

  When the final tightening operation of the bolt 14 is started, a compressive load (fastening load) by the bolt 14 acts on the rear sound absorbing cover member 21r, and the protrusion 33 starts to deform in the bolt axial direction. In a state where the final tightening of the bolt 14 is completed (a state where the entire small-diameter shaft portion 16 of the bolt 14 is screwed into the screw hole 13, hereinafter referred to as a final tightened state), the protrusion 33 is compressed and deformed. The protrusion height decreases to the compression height h (<initial height H) (see FIG. 4B). As a result, the rear-side sound absorbing cover member 21r and the rear-side sound insulating cover member 22r approach a predetermined separation distance with respect to the outer surface of the engine, whereby desired sound absorbing performance and sound insulating performance can be obtained.

Here, when the positional relationship between the bolt insertion hole 25 of the rear side sound absorbing cover member 21r and the bolt insertion hole 26 of the rear side sound insulation cover member 22r is shifted, the bolt 14 is inserted into both the bolt insertion holes 25 and 26. In addition, the large-diameter shaft portion 15 of the bolt 14 is caught around the bolt insertion hole 25 of the rear side sound absorbing cover member 21r (see FIG. 11). In this case, since the tip end portion of the bolt 14 does not reach the screw hole 13 (because it does not screw enough even if it reaches), the operator unconsciously tries to tighten it while pushing the bolt 14 in the axial direction. As a result, the protrusion 33 of the sound absorbing material 23 is compressed and deformed by receiving a compressive load by the bolt 14. Therefore, the operator feels the reaction force accompanying the compressive deformation of the protrusion 33 during the temporary tightening operation, and with this (by feeling the reaction force), it is determined that the poor engagement of the bolt 14 has occurred. can do. When the operator determines that the bolt 14 is not properly bitten, the bolt 14 is loosened, the bolts 14 and 25 are aligned, and then the bolt 14 is tightened again. Thus, the assembly of the rear noise suppression cover 1r is completed. In addition, when replacing the O ₂ sensor harness 9, in order to secure a work space, the front noise suppression cover 1f may be further detached and attached. In this case, the rear noise suppression cover 1r described above may be removed. What is necessary is just to follow the procedure similar to work.

  The work of assembling the front and rear noise suppression covers 1f, 1r to the engine 2 is not limited to being performed in the on-vehicle environment described above, and is also performed, for example, at the time of vehicle manufacture. In the assembly work at the time of manufacturing the vehicle, it is advantageous in that it is easy to ensure visibility as compared with the assembly work in the on-vehicle environment, but the merit of providing the protrusion 33 is enormous in the following points. .

  That is, when the vehicle is manufactured, for example, the front noise suppression cover 1f is first assembled to the engine 2 and then the rear noise suppression cover 1r is assembled to the engine 2. And the rear sound absorbing cover member 21r are first arranged on the outer surface of the engine 2 (chain case 6), and the front sound insulating cover member 22f and the rear sound insulating cover member 22r are superposed on the outer side of these engines. . For this reason, it is difficult for an operator to visually observe the position of the bolt insertion hole 25 of each sound absorbing cover member 21f, 21r. In addition, since the stepped bolt 14 is used, the bolt insertion hole 25 is likely to be a shadow of the large-diameter shaft portion 15 when the bolt 14 is inserted, and it is even more difficult for the operator to confirm the position of the bolt insertion hole 25 by visual inspection. As a result, displacement between the bolt insertion holes 25 of the sound absorbing cover members 21f and 21r and the bolt insertion holes 26 of the sound insulation cover members 22f and 22r is likely to occur.

  On the other hand, in this embodiment, the projection 33 is provided on the sound absorbing cover member 21, so that the large-diameter shaft portion 15 of the bolt 14 is inserted into the bolt insertion hole 25 during the temporary fastening operation of the bolt 14. Since this is the state, the final tightening operation is smooth. Further, if the sound absorbing cover member 21 is misaligned (the positional relationship between the bolt insertion holes 25 and 26 is misaligned) and the large-diameter shaft portion 15 of the bolt 14 is caught around the bolt insertion hole 25. When the bolt is screwed in during the temporary tightening operation, the operator receives the compression reaction force of the protrusion 33 and feels the rotational resistance of the bolt, so that it is possible to sense a work abnormality.

  Here, in order for the worker to reliably feel the work abnormality during the temporary tightening operation of the bolt 14, it is necessary to reliably transmit the reaction force accompanying the compression deformation of the protrusion 33 to the worker's hand via the bolt 14. There is. However, if the distance between the projection 33 and the bolt 14 is increased, the reaction force is attenuated by the bending of the shape retaining plate 24 or the like before being transmitted to the bolt 14.

  On the other hand, in the above embodiment, the protrusion 33 is provided in the vicinity of the periphery of the bolt insertion hole 25 in each of the sound absorbing cover members 21f and 21r (see FIGS. 5 and 6). During the tightening operation, the position of the bolt 14 can be as close as possible to the protrusion 33. Therefore, the reaction force accompanying the compression deformation of the protrusion 33 can be reliably transmitted to the operator's hand through the bolt 14.

  Furthermore, in the said embodiment, since the said projection part 33 was integrally formed in the sound-absorbing material 23 of each sound-absorbing cover member 21f, 21r, the part except the projection part 33 in the sound-absorbing material 33 ( Hereinafter, the sound absorbing main body portion 35) is made of the same kind of material, and the difference in rigidity between them can be reduced. Thereby, when the compressive load by the volt | bolt 14 acts with respect to the projection part 33, it can suppress that the projection part 33 sinks in the sound absorption main-body part 35, and the sound absorption main-body part 35 deform | transforms. Since the sound absorbing main body 35 has a greater influence on the sound absorbing performance than the protrusion 33, the deformation of the sound absorbing main body 35 is suppressed, so that a decrease in the sound absorbing performance is also suppressed.

Further, in the case where the coupler bracket 8 for the O ₂ sensor harness 9 is attached to the rear side of the noise suppression cover 1 of the engine 2 as in the above embodiment, the noise suppression is performed when the O ₂ sensor harness 9 is replaced. The cover 1 gets in the way. For this reason. In order to improve the exchangeability of the O ₂ sensor harness 9, it is necessary to improve the detachability of the noise suppression cover 1.

  However, the noise suppression cover 1 is disposed in a narrow gap space 5 between the chain case 6 and the front side frame 4, and thus there is a problem that it is difficult to secure a work space necessary for attachment / detachment.

  On the other hand, in the above embodiment, the noise suppression cover 1 is divided into two parts, the front noise suppression cover 1f and the rear noise suppression cover 1r, and the sound absorbing cover members 21f and 21r constituting the noise suppression covers 1f and 1r. And the sound insulation cover members 22f and 22r are separated and the components of the noise suppression cover 1 are made into small parts. Thereby, the attachment / detachment work of the noise suppression cover 1 can be easily performed even in the narrow gap space 5 as described above.

  When the sound absorbing cover members 21f and 21r and the sound insulating cover members 22f and 22r are separated as described above, the positional relationship between the bolt insertion holes 25 and 26 is shifted during the assembly work of the noise suppression cover 1. As described above, the protrusion 33 is provided on the engine-side surface of the sound absorbing material 23 as described above, so that the operator can adjust the bolt 14 due to such displacement of the bolt insertion holes 25 and 26. Biting defects can be easily found.

(Other embodiments)
The configuration of the present invention is not limited to the above embodiment, but includes various other configurations.

  That is, in the above-described embodiment, the protrusion 33 is integrally formed with the sound absorbing material 23. However, the present invention is not limited to this, and the protrusion 33 is configured as a separate member from the sound absorbing material 23. May be. In this case, the rigidity of the protrusion 33 and the rigidity of the sound absorbing material 23 can be easily made different. Therefore, for example, by setting the rigidity of the protrusion 33 to be sufficiently lower than the rigidity of the sound absorbing material 23, when the compression load by the bolt 14 acts on the protrusion 33 during the temporary fastening operation of the bolt 14, the protrusion 33 By deforming only the portion 33, the deformation of the sound absorbing material 23 can be reliably suppressed. Thereby, the fall of the sound absorption performance resulting from the deformation | transformation of the sound absorption material 23 can be suppressed reliably.

  Further, the rigidity of the protrusion 33 may be set higher than the rigidity of the sound absorbing material 23. In this case, when the compression load by the bolt 14 is applied to the protrusion 33 during the temporary fastening operation of the bolt 14, the protrusion 33 sinks into the sound absorbing material 23 without being compressed and deformed. Therefore, the operator can easily feel the repulsive force of the sound absorbing material 23 generated at this time as the tightening resistance of the bolt 14 and more easily determine that the bolt 14 is not properly engaged.

  Moreover, in the said embodiment, although the example applied to the outer surface of the chain case 6 was shown as the noise suppression cover 1, it is not restricted to this, For example, the outer surface of the engine 2 or the outer surface of the oil pan 36 is shown. You may apply.

  Moreover, in the said embodiment, although the said noise suppression cover 1 is divided into 2 by the front side noise suppression cover 1f and the rear side noise suppression cover 1r, it is not restricted to this, It is further divided | segmented up and down and it is a cover structure. The parts may be further reduced into smaller parts.

  Moreover, in the said embodiment, although the state in which several peaks of the front-end | tip part of the small diameter shaft part 16 of the volt | bolt 14 screwed into the screw hole 13 is made into the temporary fastening state of the volt | bolt 14, it is not restricted to this, Temporary fastening The state may be any state as long as a part of the small-diameter shaft portion 16 of the bolt 14 is screwed into the screw hole 13 and a compressive load by the bolt 14 does not act on the protrusion 33.

  The present invention is useful for a noise suppression cover that is bolted to an outer surface of an engine using screw holes formed on the outer surface of an engine mounted on a vehicle. Useful for noise suppression covers.

1 Noise suppression cover
1f Front noise suppression cover
1r Rear side noise suppression cover
2 Engine
3 Crankshaft
4 Front side frame
5 Clearance space
6 Chain case
13 Screw hole
14 volts
15 Large diameter shaft
16 Small diameter shaft
17 Dish washer
18 bolt head
21 Sound absorbing cover member
21f Front sound absorbing cover member
21r Rear sound absorbing cover member
22 Sound insulation cover member
22f Front sound insulation cover member
22r Rear sound insulation cover member
23 Sound absorbing material
24 Shape retention plate
25 Bolt insertion hole 26 Bolt insertion hole 33 Projection
33a Upper protrusion
33b Lower protrusion
33c Intermediate protrusion
33d Upper protrusion
33e Lower protrusion

Claims (6)

A noise suppression cover that is bolted to the outer surface of the engine using screw holes formed on the outer surface of the engine mounted on the vehicle,
A sound absorbing cover member that is mounted on the outer surface of the engine and absorbs engine noise;
The sound absorbing cover member is separate from the sound absorbing cover member, and is disposed on the surface of the sound absorbing cover member on the outer side of the engine.
The bolt is a stepped bolt having a large-diameter shaft portion, and a small-diameter shaft portion protruding from one end surface of the large-diameter shaft portion in the bolt shaft direction and having a male screw formed on the outer peripheral portion,
Each of the sound insulation cover member and the sound absorption cover member has a bolt insertion hole having a hole diameter corresponding to the large-diameter shaft portion of the bolt, which is coaxial with each other,
On the engine-side surface of the sound-absorbing cover member, there is formed a protrusion that protrudes toward the engine and has a tip that comes into contact with the outer surface of the engine.
In the temporarily tightened state where only a part of the small-diameter shaft portion of the bolt is screwed into the screw hole and the compression load by the bolt does not act on the protrusion, the protrusion is inserted into the bolt of the sound absorbing cover member. In the final tightening state where the projection height is set so that the hole is positioned at the large-diameter shaft portion of the bolt and the entire small-diameter shaft portion of the bolt is screwed into the screw hole, the bolt is compressed in the bolt shaft direction. A noise suppression cover configured to be in a deformed state or in a state of being submerged in a sound absorbing cover member. The noise suppression cover according to claim 1,
The noise-suppressing cover, wherein the engine-side surface of the sound-absorbing cover member has an uneven shape corresponding to the unevenness on the outer surface of the engine. The noise suppression cover according to claim 1 or 2,
The noise suppressing cover, wherein the protrusion is provided around the bolt insertion hole on the engine-side surface of the sound absorbing cover member. The noise suppression cover according to any one of claims 1 to 3,
The sound absorbing cover member has a sound absorbing material made of a foamed resin body,
The noise suppression cover, wherein the protrusion is integrally formed with the sound absorbing material of the sound absorbing cover member. The noise suppression cover according to claim 4,
The sound absorbing cover member further includes a shape holding plate for holding the shape by being bonded to the surface of the sound absorbing material on the engine outer side,
The noise suppressing cover, wherein the bolt insertion hole of the sound absorbing cover member is constituted by a through hole formed in the shape holding plate. In the noise suppression cover as described in any one of Claims 1 thru | or 5,
The engine is disposed horizontally between a pair of left and right front side frames extending in the front-rear direction at the front of the vehicle body of the vehicle with the crankshaft directed in the vehicle width direction,
The noise suppressing cover, wherein the sound absorbing cover member and the sound insulating cover member are disposed so as to overlap with the front side frame when viewed from the vehicle width direction.

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