JPH0526288Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cylinder block structure for an engine, and particularly relates to improving the sealing performance of the mating surface between the lower surface of the cylinder block and the flange surface of an oil pan.

[Prior art] The skirt portion of the cylinder block and the side wall of the oil pan each have a vibration mode in which they open and close horizontally in a direction perpendicular to the output shaft of the engine. When excited by this, the skirt portion and oil pan violently vibrate in the above direction. Such vibrations generate noise, especially from the oil pan, and this noise accounts for 30 to 30% of the total noise generated from the engine itself.
It is estimated that it accounts for 40%.

For this reason, it has been proposed to increase the rigidity of the oil pan to suppress its vibrations; for example,
It has been proposed that the oil pan is provided with ribs to increase its rigidity (see Japanese Utility Model Application No. 61-32548). However, this product had a problem in that large welding distortion occurred in the oil pan when welding the ribs.

Therefore, it has been proposed that the oil pan be cast from an aluminum alloy to increase the wall thickness and increase the rigidity while avoiding an increase in weight.
However, since this product is cast, the flatness of the upper surface of the flange is poor, and for this reason, liquid packing such as liquid silicone rubber is used as a sealant between the upper surface of the oil pan flange and the lower surface of the cylinder block. is common. For example, as shown in FIG. It is arranged on the upper surface via a liquid packing 7. Note that when an oil pump is disposed at the position of the front cover member 3, the oil pump body exerts the same effect as the front cover member 3 described above. by the way,
Generally, the block member 2 is made of cast iron, while the front cover member 3 (oil pump body) is made of an aluminum alloy. Since the coefficient of thermal expansion (linear expansion) of aluminum alloy is larger than that of cast iron (approximately twice), the front cover member 3 is rotated by the arrows A and 2 with respect to the block member 2, respectively, depending on the temperature. It is displaced as shown by B. Furthermore, due to the vertical vibration of the output shaft of the engine, the front cover member 3 located on the front side is located further away from the vibration node than the block member 2 located on the rear side. (B direction).

With this behavior of the front cover member 3 (oil pump body), the gasket 4 is displaced in the directions shown by arrows C and D, so the liquid gasket 7 in the area shown by P is removed by the gasket 4. In this part indicated by P, cylinder block 1
There was a problem in that the seal between the mating surface of the oil pan 5 and the oil pan 5 was incomplete, resulting in oil leakage.

[Purpose of the invention] The present invention has been made in view of the above-mentioned conventional problems, and is intended to improve the effectiveness of a block member constituting the cylinder block in an engine in which a cast oil pan is attached to the lower surface of the cylinder block via a liquid packing. It is an object of the present invention to provide an engine cylinder block structure that effectively prevents a decrease in the sealing performance of a liquid packing caused by the behavior of a front cover member and prevents oil leakage.

[Structure of the invention] In order to achieve the above object, the present invention provides a cylinder block structure for an engine in which a cast oil pan is connected to the lower surface of the cylinder block via a liquid packing. and a front cover member are connected via a gasket made of an elastic material, and the corner portion of the block member and the front cover member are connected to each other through a gasket made of an elastic material. A chamfer along the edge is formed on at least one of the corners of the front cover member, and a lower end of the gasket is cut out so that the gasket is located above the upper end of the chamfer. To provide an engine cylinder block structure characterized by:

[Effects of the invention] According to the invention, even if the front cover member is displaced due to thermal expansion or vibration and the gasket repeatedly approaches and separates from the upper surface of the flange portion of the oil pan, some liquid packing is worn away. Since a sufficient amount of liquid packing is retained in the space where the chamfered portion is formed, seal breakage does not occur. Therefore, it is possible to effectively prevent a decrease in the sealing performance between the cylinder block and the oil pan due to the behavior of the block member and the front cover member, and to prevent oil leakage. Also, so that the gasket is located above the upper end of the chamfered part,
Since the lower end of the gasket is notched, even if the front cover member is vertically displaced, the gasket does not approach the upper surface of the flange portion of the oil pan. Therefore, even when the front cover member is displaced up and down, the liquid packing near the mating surface is difficult to be removed, and the sealing performance is further improved.

[Example] Hereinafter, embodiments of the present invention will be described in detail.

As shown in FIG. 1, the outer shape of the engine E is formed around a cylinder head 11 and a cylinder block 12. A cylinder head cover 13 is provided on the upper part of the cylinder head 11, while a cylinder head cover 13 is provided on the lower part of the cylinder block 12. An oil pan 14, which will be explained in detail later, is provided. Then, the engine E receives the intake air (mixture air) is taken in through the intake passage 15, and the thermal energy generated when this air-fuel mixture is combusted is converted into rotational energy of an output shaft (not shown) and extracted, and this rotational energy is transferred to the transmission. The configuration is such that the signal is transmitted to the wheels via 18.

Incidentally, an oil pan 14 is attached to the lower part of the cylinder block 12 to store lubricating oil for lubricating each lubricating part of the energy E.
The lubricating oil stored in the lubricant 4 is supplied to each lubricating portion by an oil pump (not shown) located in an oil pump body 19 serving as a front cover member. And oil pan 1
The amount of lubricating oil stored in the cylinder head cover 1 can be checked using the oil level gauge 21. If the lubricating oil amount is less than the predetermined amount,
The lubricating oil can be supplied from a lubricating oil supply port 22 provided at the upper part of the lubricating oil.

The oil pan 14 is cast from an aluminum alloy in order to increase the wall thickness and increase the rigidity while avoiding an increase in weight. This increases the rigidity of the oil pan 14, making it possible to effectively suppress vibrations that cause noise as described in the prior art of the present application.

As shown in detail in FIG. 2, a flange portion 23 is formed at the upper part of the oil pan 14, and the upper surface of this flange portion 23 is connected to the cylinder block 12 through a liquid packing 26 (see FIG. 3) made of liquid silicone rubber. It is closely connected to the bottom surface of. The cylinder block 12 is composed of a front cover member 24 including the oil pump body 19 and a block member 25.
and are tightly connected via a rubber gasket 27 (see FIG. 3). In this way,
At the part indicated by arrow S, the oil pump body corner 28 and the block member corner 29 are connected to the gasket 27.
These corner portions 28 and 29 are disposed in close contact with the upper surface of the flange 23 via a liquid packing 26.

As shown in detail in FIG. 3, the oil pump body corner 28 extends along the edge (third
A chamfered portion 31 is formed by cutting to a predetermined position (direction perpendicular to the plane in which the figure is drawn). Correspondingly, the lower end of the gasket 27 is cut out at a portion below the extension plane of the chamfered portion 31. In this way, the lower end of the gasket 27 is connected to the flange 2.
As shown by d from the top surface of 3, a considerably larger gap is ensured compared to the conventional one (see FIG. 5). Therefore, even if the oil pump body 19 is displaced in the direction shown by arrow E due to thermal expansion or vertical vibration, and the gasket 27 is accordingly displaced in the same direction, the lower end portion of the gasket 27 and the flange portion 23 Since a sufficient gap is left between the liquid packing 26 and the upper surface, the liquid packing 26 in this area is not completely removed.
Further, since the liquid packing 26 is retained in the space between the oil pump body 19 and the flange portion 23 created by forming the chamfered portion 31, the liquid packing 26 is retained due to the above-described behavior of the oil pump body 19. Even if the cylinder block 12 and the oil pan 14 wear out to some extent, the seal does not break, and the sealing properties of the mating surfaces of the cylinder block 12 and the oil pan 14 are maintained well, and oil leakage can be effectively prevented.

As shown in FIG. 4, a chamfered portion 31 is formed at the corner portion 28 of the oil pump body.
A similar chamfered portion 32 may also be formed at the block member corner 29. In this case, the gasket 27 is cut out below the extension plane of the double-sided chamfered portions 31, 32. In this way, the number of steps for chamfering doubles, but more liquid packing 26 is retained near the chamfered portions 31, 32, thereby further improving the sealing performance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory side view of an engine showing an embodiment of the present invention. FIG. 2 is a perspective explanatory view of the engine oil pan and its surroundings, showing the connection state between the block member of the cylinder block, the oil pump body, and the oil pan. FIG. 3 is an explanatory cross-sectional view around the chamfered portion showing a state in which a chamfered portion is formed on the corner portion of the oil pump body and the oil pump body, the block member, and the oil pan are connected. FIG. 4 is a view similar to FIG. 3, showing an embodiment in which chamfered portions are formed on both the corner portions of the oil pump body and the corner portions of the block member. FIG. 5 is an explanatory cross-sectional view showing a state of connection between an oil pump body, a block member, and an oil pan in a conventional oil pump. E...Engine, 11...Cylinder head, 1
2...Cylinder block, 14...Oil pan,
19...Oil pump body, 23...Flange part, 24...Front cover member, 25...Block member, 26...Liquid packing, 27...Gasket, 28...Oil pump body corner part, 29
...Block member corner portion, 31, 32... Chamfered portion.

Claims (1)

[Claim for Utility Model Registration] In an engine cylinder block structure in which a cast oil pan is connected to the lower surface of the cylinder block via a liquid packing, the block member and front cover member that constitute the cylinder block are made of an elastic material. A corner of the block member and a corner of the front cover member are connected through a gasket, and in the vicinity of a position where the mating surface of the block member and the front cover member faces the upper surface of the flange portion of the oil pan. A cylinder block for an engine, characterized in that a chamfered portion along an edge is formed on at least one side, and a lower end of the gasket is cut out so that the gasket is located above the upper end of the chamfered portion. structure.