JPH0640914Y2 - Engine sound insulation cover mounting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sound insulation cover mounting device for an engine, for example, for preventing vibration sound emission of a head cover of a diesel engine.

(Prior Art) Conventionally, as a sound insulation cover mounting device for the engine of the above-mentioned example, there is, for example, a device described in Japanese Utility Model Laid-Open No. 60-3242.

That is, as shown in FIG. 3, a cylinder head cover 32 as an inner cover having a through hole 31 formed therein, a mount rubber 33 forming a predetermined gap with respect to the cylinder head cover 32, and a sound insulating cover for the mount rubber 33. The sound insulation cover 35 disposed in the fitting groove 34 is provided, and the sound insulation cover 35 is disposed on the upper surface of the cylinder head cover 32 via the mount rubber 33, and is pressed onto the mount rubber 33 outside the sound insulation cover 35. The member 36 is provided, and the through hole 31 described above is provided.
Bolt 38 inserted in the engine and fixed to the engine body 37
This is a device in which a nut 40 is screwed onto the upper end screw portion 39 of the above, and the sound insulating cover 35 is attached via the holding member 36 and the mount rubber 33 by this nut 40.

However, as is apparent from FIG. 3, the mount rubber 33 described above has a first thickness t4 between the outer diameter portion of the sound insulation cover fitting groove 34 of the rubber 33 and the contact surface of the pressing member 36, and the sound insulation. The second thickness t5 between the cover fitting groove 34 and the abutting surface of the cylinder head cover 32 and the third thickness t6 between the inner diameter portion of the sound insulation cover fitting groove 34 and the surface on the side of the holding member 36 are approximately respectively. Due to the equal setting, there were the following problems.

That is, when the sound insulation cover 35 receives a load from above, since the portion is relatively easily bent due to the thickness of the second thickness t5, the sound insulation cover 35 is easily displaced downward, and the sound insulation cover 35 is easily deformed. There was a problem that the position accuracy of could not be improved.

Further, since the above-mentioned first thickness t4 is not sufficiently thick, there is a problem that the vibration transmission from the rigid body to the sound insulating cover 35 cannot be sufficiently attenuated and absorbed in this portion.

Furthermore, the above-mentioned first thickness t4 and third thickness t6 are substantially equal,
Due to the increase in the shearing stress of the third thickness portion, when the compressive load due to the interference is applied, the mount rubber 33 is apt to be cracked from the edge portion of the sound insulating cover fitting groove 34.

(The purpose of the device) This device improves the reliability of the mount rubber,
An object of the present invention is to provide a sound insulation cover mounting device for an engine, which can improve the positional accuracy of the outer sound insulation cover and reduce vibration transmission to the sound insulation cover.

(Structure of the Invention) The present invention includes an inner cover having a through hole, a sound insulation cover attached to the inner cover with a predetermined gap,
And a mount rubber having a fitting groove formed in the sound insulating cover, wherein the sound insulating cover is arranged on the inner cover via the mount rubber, and a pressing member is arranged on the mount rubber outside the sound insulating cover. Then, in a sound insulation cover mounting device of an engine in which a sound insulation cover is mounted via the pressing member and a mount rubber with a bolt inserted into the through hole and fixed to the engine main body, a sound insulation cover fitting at an outer diameter portion of the mount rubber. The first thickness between the groove and the pressing member contact surface is set to be thicker than the second thickness between the sound insulation cover fitting groove and the inner cover contact surface in the outer diameter portion, and the mount rubber A sound insulating cover mounting device for an engine, wherein a third thickness between the fitting groove and the surface on the side of the pressing member in the inner diameter portion of the sound insulating cover fitting groove is set thinner than the first thickness. And characterized in that.

(Effect of the Invention) According to this invention, since the above-mentioned second thickness is set smaller than the first thickness, when the sound insulation cover receives a load from above, the second thickness Since the amount of deformation is small and the downward displacement of the sound insulation cover is small, there is an effect that the positional accuracy of the sound insulation cover can be improved.

Further, since the above-mentioned first thickness is set thicker than the second thickness, there is an effect that the vibration transmitted from the rigid body to the sound insulation cover can be sufficiently attenuated and absorbed by the first thickness.

Furthermore, since the above-mentioned third thickness is set smaller than the first thickness, the tightening margin of the mount rubber partially acts on the portion corresponding to the first thickness, and the inner edge portion of the sound insulation cover fitting groove is There is an effect that the mount rubber is prevented from being cracked without receiving a compressive load due to the tightening margin, and the reliability of the mount rubber can be improved.

Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows a sound insulation cover mounting device for a diesel engine, in which a cylinder head 1 is provided with fuel injection nozzles 4 using nozzle holder bolts 2 and nozzle holders 3,
A fuel injection pump (not shown) is configured to distribute and supply fuel to these fuel injection nozzles 4 through a fuel pipe 5, and a fuel return hose 6 is attached to communicate with the nozzle spring chamber.

On the other hand, a cylinder head cover 7 is provided as an inner cover for covering the valve operating chamber of the cylinder head 1, and the cylinder head cover 7 is fixed to the cylinder head 1 via a head cover gasket 8.

In addition, a sound insulating cover 10 as an outer cover is provided on the top surface of the cylinder head cover 7 via a mount rubber 9.
The cylinder head cover 7 and the fuel injection pump 4 are covered with the sound insulation cover 10.

The entire circumference of the lower edge of the sound insulating cover 10 is a heat-resistant seal member.
11 is fitted.

By the way, the mount rubber 9 is a floating rubber which forms a predetermined gap with the cylinder head cover 7 as shown in FIG. 2, and the sound insulating cover 10 is fitted to the outer diameter portion of the mount rubber 9. A groove, that is, a sound insulation cover fitting groove 12 is formed.

Thus, the sound insulation cover 10 is arranged on the cylinder head cover 7 via the mount rubber 9, and
The pressing member 13 is arranged on the mount rubber 9 protruding outward from the sound insulating cover 10, and the through hole of the cylinder head cover 7 is provided.
The sound insulation cover 10 is attached via the above-mentioned pressing member 13 and mount rubber 9 by means of bolts 16 which are inserted into 14 and fixed to the protrusion 15 on the engine body side.

As shown in FIG. 2, the first thickness t1 between the sound insulation cover fitting groove in the outer diameter portion of the mount rubber 9 and the contact surface of the pressing member 13 is defined as the sound insulation cover fitting in the outer diameter portion. Second thickness between the groove 12 and the contact surface of the cylinder head cover 7
It is set thicker than t2.

In other words, the spring constant of the first thickness t1 portion is set small and the spring constant of the second thickness t2 portion is set large.

In addition, the third thickness t3 between the fitting groove 12 and the upper end surface on the side of the pressing member 13 in the inner diameter portion of the sound insulating cover fitting groove 12 of the mount rubber 9 described above is smaller than the first thickness t1 described above. It is set thin.

That is, the dimensions of each part of the mount rubber 9 are set so that the relational expressions of t1> t2 and t1> t3 are satisfied.

The illustrated embodiment is configured as described above, and the operation will be described below.

The DLL-S type and other hole nozzles used in the diesel engine described above press the nozzle tip with a nozzle spring against the valve seat of the outer cylinder having a suck hole (blank hole) communicating with the injection port, and at the time of fuel injection. The tapered cone portion at the tip of the nozzle is pushed up by the fuel pressure against the nozzle spring, and the fuel is injected from the above-mentioned injection port.

When the nozzle is seated at the original position by the above-mentioned nozzle spring, noise as a seating sound is generated, but since the fuel injection nozzle 4 is covered with the sound insulation cover 10, it is possible to reduce the seating sound of the injection nozzle. it can.

By the way, the second thickness t2 of the mount rubber 9 described above.
Is set to be smaller than the first thickness t1, so that the sound insulation cover 10 receives a load from above due to, for example, a tool being placed on the sound insulation cover 10 or a worker getting on during the maintenance. At this time, since the above-mentioned second thickness t2 is sufficiently small, the amount of deformation of the second thickness t2 portion of the mount rubber 9 is small, and as a result, the downward displacement of the sound insulation cover 10 is small, and the cover 10 and the fuel pipe are Interference with 5 is prevented.

Therefore, it is possible to improve the positional accuracy of the sound insulation cover 10, and as shown in FIG.
Since the gap g between the inner surface and the fuel pipe 5 can be set small, the overall height of the sound insulation cover 10 can be lowered, and the cover 10 can be made compact and compact.

Further, since the first thickness t1 of the mount rubber 9 is set sufficiently thicker than the second thickness t2, each element 16, 13 as a rigid body is
Vibrations transmitted to the sound insulating cover 10 through the above in this order are sufficiently attenuated and absorbed by the first thickness t1 portion, and the vibration transmission can be reduced.

In addition, since the third thickness t3 of the mount rubber 9 is set smaller than the first thickness t1, the tightening margin of the mount rubber 9 acts on the portion of the first thickness t1 so that the sound insulation cover is fitted. Ditch
The inner diameter edge of 12 does not receive the compressive load due to the interference.

As a result, it is possible to prevent the mount rubber 9 from cracking and improve the reliability of the mount rubber 9.

In short, the dimensions of each part of the mount rubber 9 should be t1> t
2. Since the relational expression of t1> t3 is established, it is possible to improve the reliability of the mount rubber 9 and at the same time improve the positional accuracy of the sound insulation cover 10 and reduce the vibration transmission to the sound insulation cover 10. There is an effect that can be achieved.

In the correspondence between the configuration of the present invention and the above-described embodiment, the inner cover of the present invention corresponds to the cylinder head cover 7 of the embodiment, and the engine body is integrally attached to the cylinder head 1 in the same manner. Even if it corresponds to the protrusion 15, the present invention is not limited to the configuration of the above-described embodiment.

[Brief description of drawings]

The drawings show an embodiment of the present invention, FIG. 1 is a sectional view showing a sound insulation cover mounting device for a diesel engine, FIG. 2 is an enlarged cross sectional view of a main portion of FIG. 1, and FIG. 3 is a conventional sound insulation cover. It is sectional drawing which shows an attachment device. 7 …… Cylinder head cover 9 …… Mount rubber, 10 …… Sound insulation cover 12 …… Sound insulation cover fitting groove 13 …… Pressing member, 14 …… Through hole 15 …… Projection, 16 …… Bolt t1 …… First Thickness, t2 …… 2nd thickness t3 …… 3rd thickness

Claims (1)

[Scope of utility model registration request] 1. An inner cover having a through hole, a sound insulating cover attached to the inner cover with a predetermined gap, and a mount rubber having a fitting groove for the sound insulating cover. The sound insulation cover via the mount rubber, and a pressing member on the mount rubber outside the sound insulation cover, and the presser foot is fixed by a bolt inserted into the through hole and fixed to the engine body. In a sound insulating cover mounting device for an engine, in which a sound insulating cover is mounted via a member and a mount rubber, a first thickness between a sound insulating cover fitting groove and a pressing member contacting surface in an outer diameter portion of the mount rubber is The thickness is set to be thicker than the second thickness between the sound insulation cover fitting groove and the inner cover contact surface in the diameter portion, and the inner diameter portion of the sound insulating cover fitting groove of the mount rubber is set. Sound insulating cover mounting device for an engine of the third thickness set thinner than the first thickness above between the fitting groove and the pressing member side surface which definitive.