JPH0441237Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gasket interposed between a cylinder block and a cylinder head of an internal combustion engine, and more particularly to an improvement in a grommet provided in the gasket.

[Prior Art] Conventionally, a grommet in a gasket is attached along the inner periphery of a hole in the gasket through which oil, water, etc. can pass, and is tightened to two members, a cylinder block and a cylinder head, to exert a sealing force.

[Problem to be solved by the invention] However, with the above structure, a buckling phenomenon occurs in which the grommet partially or completely peels off from the inner periphery of the gasket hole due to the combustion gas pressure coming from the cylinder bore, and the grommet no longer functions as a sealing material. There was a high risk of losing it.

In order to avoid this risk, for example, as shown in Fig. 1, the thickness of the grommet A1 is increased so that the upper and lower outer circumferential edges 1 cover the circumferential surface of the hole 2 of the gasket B, so that the outer circumferential edge 1 receives stronger local pressure. or grommet A2 as shown in Figure 2.
A structure in which a reinforcing core material 3 is buried inside has been devised. However, none of these can be a fundamental countermeasure against gas leaks. In other words, the grommet A1 that attempts to obtain the former strong local surface pressure shown in FIG. Since it is easily crossed, it is easily destroyed, and it is also troublesome to attach. In addition, grommet A2 including the latter reinforcing core material 3 shown in FIG.
The reinforcing core material has many drawbacks, such as the fact that the thickness of the reinforcing core material is deprived of its elasticity, resulting in insufficient elasticity and a tendency to cause stress fractures.

The present invention eliminates many of these drawbacks and provides a grommet to be attached to a gasket that has a simple structure, is easy to install, and exhibits excellent sealing performance.

[Means for Solving the Problems] As shown in Fig. 3, the present invention uses an elastic material such as synthetic rubber or synthetic resin that is installed along the inner periphery of the hole 2 provided in the gasket B through which oil or water passes. The grommet A3 is formed of a metal body, and the grommet A3 has an annular groove 4 on its inner circumference, and the annular groove 4 is made of metal such as iron, stainless steel, brass, etc.
Alternatively, the grommet A3 is characterized in that a reinforcing ring 5 made of a hard synthetic resin or the like having sufficient strength and having a thickness that contacts the compression member and regulates the size of the gasket B is engaged.

[Function] This structure is disadvantageous in terms of weight.
It can be easily molded and installed without the disadvantages and troublesome effort of inserting a core material 3 coated with adhesive or the like in advance during grommet molding, and has a dramatic sealing force. It has achieved improvement, and its effect is the third one.
When the grommet A3 with the reinforcing ring 5 shown in the figure is installed between the cylinder block and the cylinder head and tightened, the upper and lower surfaces of the grommet A3 are compressed, exerting elasticity in and out of the circumferential direction and causing a lateral flow. However, the outer periphery of the grommet A3 is blocked by the inner wall of the hole 2 of the gasket B, and the inner periphery is also engaged with a reinforcing ring 5 having sufficient strength, so there is no place for lateral flow. As a result, a tension force was accumulated inside the grommet A3, which is an elastic body, and exhibited extremely high sealing performance. Grommet A3, which maintains such a high tension force, not only completely prevents the buckling phenomenon, which is the initial purpose of grommet A3, which is caused by succumbing to the pressure of combustion gas from the cylinder bore, but also because it does not include or pinch other parts. Partial loads that cause stress failure are eliminated, ensuring a long-term, unchanging seal.

In addition, such a gasket A usually has an appropriate range of tightening pressure, and if this range is exceeded, the cylinder volume and compression ratio will change, and in terms of performance, cylinder head distortion and block distortion will occur, reducing the sealing force. significantly lower. In order to obtain this appropriate tightening pressure range, conventional methods required delicate and troublesome tightening adjustments, but the grommet A3 of the present invention
Even if the reinforcing ring 5 is over-tightened, it has appropriate rigidity and hardness, so it comes into contact with the cylinder head and cylinder and functions to regulate the tightening dimension, and adjusts the height or diameter of the reinforcing ring 5. By doing so, desired tightening dimensions and appropriate compression can be easily obtained.

[Effects of the invention] As explained above, according to the structure of the invention, not only can the backling phenomenon of the grommet A3 be completely prevented, but also the reinforcing ring 5 can be attached to the grommet A3.
When tightening, the reinforcing ring 5 directly contacts the tightening members on both sides to immediately stop the compression, and the tightening dimension is regulated by the height of the reinforcing ring 5, dramatically improving the sealing force. different reinforcement rings 5
This is an ideal grommet structure that simplifies the adjustment of tightening torque.

[Brief explanation of the drawing]

1 and 2 are partial cross-sectional views of a conventional grommet. FIG. 3 is a partial sectional view showing one embodiment of a grommet equipped with a reinforcing ring of the present invention. A...Grommet, B...Gasket, 1...
Upper and lower outer peripheral edges, 2... hole, 3... reinforcing core material, 4...
...Annular groove, 5...Reinforcement ring.

Claims (1)

[Scope of utility model registration request] In a grommet made of an elastic material such as synthetic rubber that is attached along the inner periphery of an oil or water hole provided in a gasket; the grommet has an annular groove on its inner periphery, and a metal A grommet characterized by engaging a reinforcing ring made of resin or the like and having a thickness that controls the size of the gasket by contacting the compression member.