GB2039604A

GB2039604A - Internal combustion engine covers

Info

Publication number: GB2039604A
Application number: GB7900273A
Authority: GB
Original assignee: Perkins Engines Ltd
Current assignee: Perkins Ltd
Priority date: 1979-01-04
Filing date: 1979-01-04
Publication date: 1980-08-13
Also published as: GB2039604B

Abstract

Timing case covers of internal combustion engines are constructed of relatively thin material and liable to transmit noise generated by the vibrations of the engine. To reduce such vibrations an elastomeric seal 3 having a longitudinal groove 4 engaging the rim 2 of the timing case cover 1 is clamped by clamping pieces 5 co- extensive with the rim to the mounting surface 9 by bolts 8 spaced from the cover and the cover is therefore vibrationally isolated from the engine. <IMAGE>

Description

SPECIFICATION Vibrationally isolated cover assembly This invention relates to a component for attachment to an internal combustion engine by means of a rim or flange, for exampie, a timing case cover, or an oil sump.

Such components are conventionally secured to the engine by bolts passing through holes in the rim or flange and in a gasket intersposed between the rim or flange and the mounting surface to effect sealing of the joint. Some components are of relatively thin material and during operation vibrate and emit noise. Timing case covers and oil sumps are secured in position in the conventional manner referred to above and in consequence of the continuous path for transmission of vibration from the engine through the bolts to the component, a significant amount of noise is emitted by these components. Previous attempts to reduce noise have centred on providing damping material on the outside ofthe component.

According to the present invention there is provided a component for attachment to an internal combustion engine by means of a rim orflange comprising clamping means co-operable with the rim orflangeforsecuring the component to a mounting surface on the engine, elastomeric, vibration absorbing, sealing material sealingly intersposed between the clamping means and the rim or flange and between the rim or flange and the mounting surface, the clamping means and the sealing material being co-extensive with the rim or flange, and fastening means for securing the clamping means to the mounting surface being spaced from the rim or flange, wherein the component is vibrationally isolated from the engine.

The present invention is particularly applicable to the vibrational isolation of a timing case cover, and of an oil sump for an internal combustion engine, both of which are usually mounted by means of a flange.

Preferably, the component comprises a planar peripheral rim orflange portion, an elastomeric sealing member having a longitudinally extending groove engageable on the rim orflange and coextensive therewith, clamping means co-extensive with the sealing member having a portion adapted to be secured to a mounting surface on the engine and a flange portion engageable with the sealing member when located on the rim or flange to clamp the sealing member on the mounting surface in sealing engagement, the sealing member being of sufficient thickness substantial Iy to isolate the com- ponent from vibrations transmitted by the mounting surface or by the clamping means.

The clamping means may advantageously be in two or more pieces to facilitate manufacture and fitting particularly where the periphery of the component includes re-entrant portions or is of complicated shape.

Preferably, the clamping means have an L shaped cross section, one of the arms of the L being a flange for engagement with the sealing member and the other arm being arranged to seat upon the mounting surface and be there secured by bolts passing through holes therein.

The sealing member is made form an elastomeric material which is resistant to oil and fuel such as neoprene or nitrile rubber or silicone rubber. The absence of holes in the sealing member for accommodating bolts as in conventional gaskets provides the maximum surface area of uniform width for effecting sealing.

An em bodiment of the invention will now be described, by way of example, with reference to the accompanying drawings of which: Figure 1 is a plan view of the outer face of a timing case cover in accordance with the invention showing two of the clamping pieces and a portion of the seal located in their assembled positions.

Figure 2 is an elevational cross sectional view of an edge portion of the cover showing the clamping means and the seal.

Referring to the drawings, the cover 1 comprises a thin aluminium casting having a planar rim 2 extending around the whole of the periphery of the cover 1. An oil resistant rubber seal 3, of which a partial view is shown in Figure 1 having a longitudinal groove 4, receives in the groove 4 the rim 2 and the seal 3 thus encloses the rim 2 around the whole perimeter of the cover 1. Clamping pieces 5, each conforming to a portion of the perimeter of the rim 2, are of L shaped section, comprise an outer portion 6 in which are provided holes 7 through which bolts 8 secure the clamping pieces 5 to a mounting 9.

An inwardly extending flange 10 engages the upper surface of the seal 3 and applies a compressive force thereto whereby the sides of the groove 4 firmly grip the rim 2 and the lower surface of the seal 3 is clamped against the mounting 9.

The seal 3 thus secures the cover 1 firmly and because of the vibration absorption properties of the elasomeric material the cover 1 is isolated vibrationally from the mounting 9 since there is no metal contact between the cover 1 and the clamping pieces 5.

If desired the clamping means can be a single clamping piece 5 extending completely around the rim 2 but there are manufacturing advantages in having two or more pieces.

The components forming the cover assembly herein described are particularly suited to manufacture by a die casting process, for example, in an aluminium alloy, and the seal can be produced by extrusion, the invention thus being suited to high volume production.

1. Acoverassemblyforan internalcombustion engine comprising a cover portion having a peripheral rim portion, clamping means for securing the rim portion of the cover portion to a mounting surface on the crankcase of the engine, elastomeric, vibration absorbing, sealing material sealingly interposed between the clamping means in the rim portion and between the rim portion and the mounting surface, the clamping means and the sealing

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Vibrationally isolated cover assembly This invention relates to a component for attachment to an internal combustion engine by means of a rim or flange, for exampie, a timing case cover, or an oil sump. Such components are conventionally secured to the engine by bolts passing through holes in the rim or flange and in a gasket intersposed between the rim or flange and the mounting surface to effect sealing of the joint. Some components are of relatively thin material and during operation vibrate and emit noise. Timing case covers and oil sumps are secured in position in the conventional manner referred to above and in consequence of the continuous path for transmission of vibration from the engine through the bolts to the component, a significant amount of noise is emitted by these components. Previous attempts to reduce noise have centred on providing damping material on the outside ofthe component. According to the present invention there is provided a component for attachment to an internal combustion engine by means of a rim orflange comprising clamping means co-operable with the rim orflangeforsecuring the component to a mounting surface on the engine, elastomeric, vibration absorbing, sealing material sealingly intersposed between the clamping means and the rim or flange and between the rim or flange and the mounting surface, the clamping means and the sealing material being co-extensive with the rim or flange, and fastening means for securing the clamping means to the mounting surface being spaced from the rim or flange, wherein the component is vibrationally isolated from the engine. The present invention is particularly applicable to the vibrational isolation of a timing case cover, and of an oil sump for an internal combustion engine, both of which are usually mounted by means of a flange. Preferably, the component comprises a planar peripheral rim orflange portion, an elastomeric sealing member having a longitudinally extending groove engageable on the rim orflange and coextensive therewith, clamping means co-extensive with the sealing member having a portion adapted to be secured to a mounting surface on the engine and a flange portion engageable with the sealing member when located on the rim or flange to clamp the sealing member on the mounting surface in sealing engagement, the sealing member being of sufficient thickness substantial Iy to isolate the com- ponent from vibrations transmitted by the mounting surface or by the clamping means. The clamping means may advantageously be in two or more pieces to facilitate manufacture and fitting particularly where the periphery of the component includes re-entrant portions or is of complicated shape. Preferably, the clamping means have an L shaped cross section, one of the arms of the L being a flange for engagement with the sealing member and the other arm being arranged to seat upon the mounting surface and be there secured by bolts passing through holes therein. The sealing member is made form an elastomeric material which is resistant to oil and fuel such as neoprene or nitrile rubber or silicone rubber. The absence of holes in the sealing member for accommodating bolts as in conventional gaskets provides the maximum surface area of uniform width for effecting sealing. An em bodiment of the invention will now be described, by way of example, with reference to the accompanying drawings of which: Figure 1 is a plan view of the outer face of a timing case cover in accordance with the invention showing two of the clamping pieces and a portion of the seal located in their assembled positions. Figure 2 is an elevational cross sectional view of an edge portion of the cover showing the clamping means and the seal. Referring to the drawings, the cover 1 comprises a thin aluminium casting having a planar rim 2 extending around the whole of the periphery of the cover 1. An oil resistant rubber seal 3, of which a partial view is shown in Figure 1 having a longitudinal groove 4, receives in the groove 4 the rim 2 and the seal 3 thus encloses the rim 2 around the whole perimeter of the cover 1. Clamping pieces 5, each conforming to a portion of the perimeter of the rim 2, are of L shaped section, comprise an outer portion 6 in which are provided holes 7 through which bolts 8 secure the clamping pieces 5 to a mounting 9. An inwardly extending flange 10 engages the upper surface of the seal 3 and applies a compressive force thereto whereby the sides of the groove 4 firmly grip the rim 2 and the lower surface of the seal 3 is clamped against the mounting 9. The seal 3 thus secures the cover 1 firmly and because of the vibration absorption properties of the elasomeric material the cover 1 is isolated vibrationally from the mounting 9 since there is no metal contact between the cover 1 and the clamping pieces 5. If desired the clamping means can be a single clamping piece 5 extending completely around the rim 2 but there are manufacturing advantages in having two or more pieces. The components forming the cover assembly herein described are particularly suited to manufacture by a die casting process, for example, in an aluminium alloy, and the seal can be produced by extrusion, the invention thus being suited to high volume production. CLAIMS

1. Acoverassemblyforan internalcombustion engine comprising a cover portion having a peripheral rim portion, clamping means for securing the rim portion of the cover portion to a mounting surface on the crankcase of the engine, elastomeric, vibration absorbing, sealing material sealingly interposed between the clamping means in the rim portion and between the rim portion and the mounting surface, the clamping means and the sealing material being co-extensive with the rim, and fastening means for securing the clamping means to the mounting surface being spaced from the cover, wherein the cover portion is vibrationally isolated from the engine.

2. A cover assembly according to claim 1 wherein the cover assembly is a timing case cover.

3. A timing case cover according to claim 2 wherein the elastomeric sealing member includes a longitudinally extending groove engageable on the rim and co-extensive therewith.

4. Atiming case cover according to claim 2 or claim 3 wherein the sealing member comprises a portion adapted to be secured to a mounting surface on the timing case and a flange portion engageable with the sealing member when located on the rim to apply a clamping force to the sealing member.

5. A timing case cover according to any of claims 2-4 wherein the clamping means is in two or more pieces.

6. A timing case cover according to any of claims 2-5 wherein the clamping means are of L shaped cross section attachable to the mounting surface by bolts passing through holes therein.