JPS6224027Y2 - - Google Patents

Description

[Detailed Description of the Invention] As shown in FIGS. 1, 2, and 3, the present invention provides a cylinder head cover that can be mounted on the top surface of a cylinder head 1 in an internal combustion engine by fastening a plurality of bolts 2, 2. The present invention relates to a device for inserting a substantially rectangular annular gasket 4 surrounding the cylinder head 1 and the cylinder head cover 3 between the cylinder head 1 and the cylinder head cover 3 for sealing.

Conventionally, in this type of sealing device, a gasket 4' made of an elastic material such as rubber and inserted between the cylinder head and the cylinder head cover is described in, for example, Japanese Utility Model Application Publication No. 50-46807, and as shown in FIG. As shown in the figure, a thick lip portion 4 is formed into a downward T-shaped cross section and is integral with the main body portion 4a', which fits into a groove 3'' provided on the lower surface 3' of the cylinder head cover 3.
b' is sandwiched between the upper surface 1' of the cylinder head 1 and the lower surface 3'' of the cylinder head cover 3.However, by forming the thick lip portion 4b' on the gasket 4 in this way, By sandwiching the thick lip portion 4b', there will be no metal contact between the cylinder head 1 and the cylinder head cover 3, which will prevent the generation of noise and the transmission of vibrations at the time of metal contact. Not only is the seal low because it makes contact with the upper surface of 1 over a wide area, but lip portion 4b' is subjected to repeated heat loads and changes in tightening force under the condition of being considerably tightened between the two, so it is susceptible to aging and wear. tend to occur,
When the lip portion ages and wears out, the sealing performance of the gasket is extremely reduced, so it must be replaced with a new one, resulting in low durability.

Furthermore, the cylinder head cover 3 can be attached to the cylinder head 1 by tightening a plurality of bolts 2, 2 with a gasket 4 made of an elastic material such as rubber sandwiched between them. As shown by the dotted chain line 5, it tends to be distorted into a curved shape. In this case, when the contact area is large as in the conventional gasket 4', the bolt tightening force must be increased in order to obtain the desired sealing performance, but if the bolt tightening force is increased, the result will be as shown by the two-dot chain line 5. As the curved deformation of the cylinder head cover increases, the sag of the gasket near the bolts increases, while the tightness of the gasket at the intermediate portions of each bolt decreases.

The purpose of the present invention is to solve these problems, and its gist is to provide a cylinder head cover that is inserted between the top surface of the cylinder head and the bottom surface of the cylinder head cover that is bolted thereto. In a gasket made of an elastic material such as rubber, the main body portion of the gasket is placed in a groove formed on the lower surface of the cylinder head cover, and a portion of the main body portion protrudes from the lower surface of the cylinder head cover by an appropriate height. At the same time, the main body part has a thin flat lip part extending in the lateral direction with a thickness smaller than the protruding height of the main body part, so that the upper surface of the lip part is attached to the lower surface of the cylinder head cover. This is because they are integrally installed at close height positions.

Hereinafter, the embodiments shown in the drawings will be described. The gasket 4 made of an elastic material such as rubber in the present invention is
The main body portion 4a that fits into the groove 3'' cut in the lower surface 3' of the cylinder head cover 3 has a round cross section (the fourth
Figure) or trapezoidal (Figure 5) or rectangular (Figure 6)
Alternatively, the main body portion 4a has an elliptical shape, etc., and when the main body portion 4a is fitted into the groove 3″, the main body portion 4a has an appropriate dimension h from the lower surface 3′ of the cylinder head cover 3 (the thickness t of the lip portion 4b to be described later). The gasket 4 of the present invention is configured to protrude by a dimension (adding an appropriate compressive deformation dimension λ of the portion 4a).Furthermore, the gasket 4 of the present invention is configured to protrude from the cylinder head cover from both left and right sides of the main body portion 4a that fits into the groove 3''. 3 bottom surface 3'
The main body portion 4a is provided with a lip portion 4b that integrally extends in the lateral direction along the lower surface 3' of the cylinder head cover 3 of the main body portion 4a.
The thickness t of the dimension smaller than the protrusion height dimension h from
This lip portion 4 is formed into a thin flat shape.
b is provided at a height such that its upper surface is in close contact with the lower surface 3' of the cylinder head 3.

In this way, the main body portion 4a of the gasket 4
A thin flat lip portion 4b extending laterally from
, whose upper surface is the lower surface 3' of the cylinder head 3.
By providing the gasket 4 at a height close to the upper surface 1' of the cylinder head 1, the lower surface of the main body portion 4a of the gasket 4 protrudes from the lower surface of the lip portion 4b by the compressive deformation dimension λ. Since the main body portion 4a is in contact with the bolt 2 of the cylinder head cover 3 against the cylinder head 1.
By fastening, the main body portion 4a is tightened, and the lip portion 4b is then brought into close contact with the upper surface 1' of the cylinder head 1. The lip portion 4b is attached to the lower surface 3' of the cylinder head cover 3.
The tightening of the bolts 2, 2 is finished when the main body portion 4a is compressed and deformed by the compressive deformation dimension λ.

In this way, the main body portion 4a of the gasket 4 according to the present invention is tightened and presses into contact with the upper surface 1' of the cylinder head 1 in a relatively narrow area, so that a large surface pressure can be obtained at the contact portion. Therefore, a reliable sealing effect can be obtained only by the main body portion 4a. In this case, since the height of the main body portion in the tightening direction is high relative to the compression deformation dimension λ, the sealing effect can be maintained for a long period of time with little settling.

On the other hand, the thin flat lip portion 4b is interposed between the lower surface 3' of the cylinder head cover 3 and the upper surface 1' of the cylinder head 1 to prevent metal contact. Part 4b
Since it is hardly subjected to any tightening force, it will not deteriorate easily, but since it is thin, it will age quickly due to repeated heat loads.However, this thin flat lip part 4b is intended to prevent metal contact and has no sealing effect. Therefore, even if the main body portion 4a becomes hard due to aging, the sealing performance of the main body portion 4a will not deteriorate, and the main body portion 4a will have the durability to withstand long-term use.

Moreover, the bolts 2, 2 only need to be tightened on the main body portion 4a of the gasket 4.
Since it is not necessary to tighten even the thin flat lip portion 4b, the tightening torque for the bolts 2, 2 can be small.Therefore, the bending distortion of the cylinder head cover 3 when tightening with the bolts is reduced, so the cylinder head cover The deterioration of sealing performance and durability due to strain deformation is less affected, and high sealing performance and durability can be obtained.

Further, according to the present invention, when tightening with bolts, when tightening of the main body portion 4a of the gasket 4 is finished and tightening of the thin flat lip portion 4b begins, the tightening torque of the bolt increases rapidly. By stopping the tightening, excessive tightening of the gasket 4 can be prevented and optimum tightening can be easily achieved.

According to experiments, the compressive deformation dimension λ of the gasket 4 is 5 to 5 of the total height H of the main body portion 4a.
Good sealing performance can be obtained when the ratio is set to around 30%.
Furthermore, since the thickness t of the thin flat lip portion 4b is equal to the compressive deformation dimension λ, it is preferable to set it to a slightly smaller dimension.

Since the thin flat lip portion 4b of the gasket 4 of the present invention has the function of preventing metal contact as described above, the tightening bolts 2, 2 of the cylinder head cover 3 as shown in FIG.
It is sufficient to provide it near the gasket 4, and it is not necessarily necessary to provide it around the entire circumference of the gasket 4.In addition, in order to completely avoid the adverse effect on sealing performance due to deformation and distortion of the cylinder head cover when tightening with bolts, it is necessary to As shown in FIG. 7, the height of the main body portion 4a is made to gradually increase as the distance from the bolt increases, depending on the deformation strain of the cylinder head cover, and the width dimension of the main body portion 4a in the gasket 4 is made to increase as the distance from the bolt increases. This can be solved by increasing the height and width of the main body portion gradually as the distance from the bolt increases. In addition, it goes without saying that the lip portion may be provided all around the gasket or only in a portion close to the tightening bolt.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the cylinder head cover attachment part to the cylinder head, Fig. 2 is a plan view of Fig. 1, Fig. 3 is a cross-sectional view taken from - in Fig. 1, and Fig. 4
Figures A and B are enlarged cross-sectional views taken from the side of Figure 2, Figure 4A shows the state before tightening, and Figure 4B shows the state after tightening. 5 and 6 are cross-sectional views of a gasket according to another embodiment of the present invention, FIG. 7 is a perspective view of a gasket according to still another embodiment of the present invention, and FIG. 8 is a cross-sectional view of the same location as in FIG. 4. 1 is a diagram showing a conventional gasket; FIG. 1... Cylinder head, 3... Cylinder head cover, 2... Bolt, 4... Gasket, 3''
... Groove, 4a ... Main body part, 4b ... Lip part.

Claims (1)

[Scope of utility model registration request] In a gasket made of an elastic material such as rubber, which is inserted between the upper surface of the cylinder head and the lower surface of the cylinder head cover that is tightened with bolts,
The main body portion of the gasket is fitted into the groove formed on the lower surface of the cylinder head cover so that a portion of the main body portion protrudes from the lower surface of the cylinder head cover by an appropriate height. A thin flat lip portion extending in the lateral direction and having a thickness smaller than the height of the protrusion in the main body portion is integrally provided at a height position where the upper surface of the lip portion is in close contact with the lower surface of the cylinder head cover. A cylinder head cover sealing device characterized by: