JP7219131B2 - Automotive internal combustion engine oil pan - Google Patents

Description

The present invention relates to an oil pan for an automotive internal combustion engine.

In an internal combustion engine, an oil pan is fixed to the lower surface of a cylinder block with bolts, and a transmission case is fixed while straddling the rear surface of the cylinder block and the rear surface of the oil pan. is configured. Also, the lower part of the front cover that covers the timing chain is often fixed to the front of the oil pan, and in this case the front cover is also part of the power plant.

What is important in the power plant is to increase the overall rigidity. Regarding this point, Patent Document 1 discloses forming recesses and ribs in the rear surface of the oil pan as means for improving the rigidity of the oil pan.

JP-A-62-247158

When an internal combustion engine for a vehicle is installed in the engine room of a vehicle body, it is roughly divided into a horizontal type in which the crankshaft center is oriented in the width direction of the vehicle and a vertical type in which the crankshaft center is oriented in the longitudinal direction of the vehicle body. Furthermore, in the horizontal type, there is a front exhaust with the exhaust side facing the front of the vehicle body, and a rear exhaust with the exhaust side facing the rear of the vehicle body. can be cooled.

Since the end of the exhaust pipe is located at the rear part of the vehicle body, in the internal combustion engine of the horizontal front exhaust system, the exhaust pipe is pulled out behind the oil pan under the oil pan. Therefore, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100003, a hollowed portion is formed in the lower surface of the oil pan, and an exhaust pipe is passed through the hollowed portion.

When the gouged portion is formed in the oil pan, the bottom of the oil pan becomes shallow at the gouged portion and deep at other portions, and the transmission case is fixed to the end of the shallow portion. Therefore, there is a problem that the rigidity of the oil pan (in particular, the rigidity against the bending force acting from the vertical direction) is reduced, and as a result the rigidity of the power plant is reduced.

Further, when examining Patent Document 1, even if the rear part of the oil pan is partially reinforced, it does not contribute much to improving the rigidity of the entire oil pan. Therefore, it is understood that it does not contribute much to the improvement of the rigidity of the power plant as a whole (in particular, it is understood that it hardly contributes to the improvement of the rigidity against an external force that bends the crankshaft in the vertical direction).

The invention of the present application was conceived in light of the current situation, and aims to realize an oil pan with a simple structure that can contribute to increasing the rigidity of a power plant.

The claimed invention is
"Internal combustion engine installed in the engine room at the front of the vehicle with the crankshaft centered in the vehicle width direction and the exhaust side facing the vehicle forward direction"
This oil pan is used for
"It has a pair of side walls to which the cylinder block is fixed on the top surface, a front wall located on the side of the front cover that covers the timing chain, and a rear wall to which the transmission case is fixed, and an exhaust pipe at the bottom. It forms a through gouge, so that the bottom is shallow at the gouge and deep at the front."
It has a basic configuration.

And in the above basic configuration ,
"A stepped or rib-shaped reinforcing portion is formed on both side walls over the entire length of the side wall when viewed from the direction of the crankshaft, and a front extension extending around the front wall at the front end. is formed, while
The front cover is fixed to the front surface of the front wall, and the front extension of the reinforcement is set at a height that overlaps with or is close to the lower end of the front cover.
It has the characteristics of

Now, since the transmission case is fixed to the rear surface of the cylinder block and the oil pan in a cantilever state, the weight of the transmission case acts on the oil pan as an external force to bend it in the vertical direction. The movement of the piston also acts as an external force that bends the cylinder block and oil pan vertically.

Since the oil pan of the horizontal front exhaust type internal combustion engine has a gouged portion, the rigidity against external force in the vertical direction (more precisely, in the axial direction of the cylinder bore) is low. Since the long side walls are provided with step-shaped or rib-shaped reinforcements over the entire length, the oil pan has significantly improved rigidity against bending and twisting in the vertical direction.

The reinforcing portion has a simple step-like or rib-like structure, and can be integrally formed, for example, when an oil pan is manufactured by die casting or casting. Therefore, cost increase and weight increase do not occur. Therefore, it is possible to improve the rigidity of the power plant comprising the cylinder block, the oil pan, and the transmission case without increasing the cost.

Adopting a stepped form as the reinforcing portion has the advantage of avoiding an increase in weight because the amount of material used does not increase. In addition, the oil returning from the cylinder block often falls along the inner surface of the side wall of the oil pan. By doing so, the air bubbles contained in the oil can be eliminated.

The oil jet that cools the piston may drop and be thrown off by the rotation of the crankshaft and adhere to the inner surface of the side wall. is reduced, air bubbles contained in the oil can be eliminated.

In this way, if the stepped portion is used as the reinforcing portion, it also has the effect of eliminating air bubbles in the oil, and thus has the advantage of being able to suppress the inclusion of air bubbles in the oil sucked up by the oil pump. In particular, when using a hydraulic lash adjuster to eliminate the valve clearance of the intake and exhaust valves, air bubbles should be avoided as much as possible in the oil. is particularly effective when applied to an internal combustion engine oil pan equipped with a lash adjuster. A similar effect can be obtained even if the reinforcing portion is formed of inward ribs.

Further, since the area of the inner surface of the oil pan is increased by forming the reinforcing portion whether it is a step-shaped reinforcing portion or a rib-shaped reinforcing portion, the oil cooling performance can be improved. Therefore, there is an advantage that excessive temperature rise of the oil can be suppressed and deterioration of the oil can be suppressed during operation in a high-temperature environment.

Further , in the present invention , since the reinforcing portion extends to the front wall, the rigidity of the oil pan and power plant can be further improved. Further, in the present invention , the front cover plays the role of a reinforcing member that strengthens the fixation between the cylinder block and the oil pan. Therefore, the front cover also constitutes a part of the power plant. Since the extended portion overlaps or is close to the lower end of the front cover, the strength of the connection between the front cover and the oil pan can be significantly improved. As a result, the rigidity of the power plant can be further improved.

1 is a plan view of an embodiment; FIG. It is a side view. It is a bottom view. It is a front view (front view). It is a back part (rear view). FIG. 2 is a sectional view taken along line VI-VI of FIG. 1;

Next, embodiments of the present invention will be described based on the drawings. In the following description, terms such as front-rear and left-right are used to specify directions, and the front-rear direction is the crankshaft center direction, and the left-right direction is the direction perpendicular to the crankshaft center and the cylinder bore centerline. Regarding the front and rear, the side where the timing chain is arranged is the front, and the side where the transmission case is arranged is the rear. The directions are clearly shown in FIG. 1 and the like.

(1) Basic Structure The internal combustion engine to which this embodiment is applied has three cylinders. As shown in FIG. Left and right side walls 3 to be fixed, a front wall 5 to which the front cover 4 is fixed, a rear wall 7 to which the transmission case 6 is fixed, and a bottom portion 9 continuous with the front and rear walls 5, 7 and the side walls 3. have. Incidentally, the crankshaft center O is located slightly above the upper surface 3a of the oil pan 1. As shown in FIG.

In FIG. 1, the range of the upper surface 3a of the side wall 3 is indicated by parallel oblique lines. Therefore, the hatched lines in FIG. 1 are not cross-sectional representations. An upper tapped hole 10 for fixing the cylinder block 2 is formed in the upper surface 3a of the side wall 3 along the circumferential direction. In addition, longitudinally elongated ribs 11 are formed on the inner surfaces of the side walls 3 at the locations of the tapped holes 10 to secure an area for forming the upper tapped holes 10 .

A hollow portion 14 through which the exhaust pipe 13 passes is formed at the rear portion of the bottom portion 9 . For this reason, the bottom portion 9 is composed of a shallow bottom portion 9a having a low depth, a deep bottom portion 9b located in front of the shallow bottom portion 9a having a large depth, and a stepped wall 9c connecting the two. Needless to say, the strainer is arranged in the deep bottom 9b.

As can be understood from FIGS. 3 and 4, the front wall 5 spreads to the left and right outer sides of the left and right side walls 3 to form a front overlapping surface 15 on which the front cover 4 overlaps. A front tapped hole 16 for fixing the front cover 4 is formed in the front overlapping surface 15 . The parallel oblique lines shown in FIG. 4 also indicate a flat surface, not a cross section. A plurality of recesses 17 that open forward are formed in the front overlapping surface 15 . Further, the front wall 5 has a front recess 18 that opens upward for receiving a front crank cap (not shown).

As shown in FIG. 5, the rear wall 7 is formed with a rear overlapped surface 19 that is in close contact with the transmission case 6, and the rear overlapped surface 19 is formed with a plurality of rear tapped holes 20 for fixing the transmission case 6. there is In the rear wall 7, a slot 21 for releasing the bearing of the crankshaft is opened upward while being concentric with the crankshaft center O. As shown in FIG.

As shown in FIGS. 1 and 6, two left and right reinforcing ribs 22 are formed on the inner surface of the shallow bottom portion 9a so as to extend in the front-rear direction. The reinforcing rib 22 reaches the deep bottom portion 9b through the stepped wall 9c. The internal combustion engine to which the present embodiment is applied is a slant type in which the axis of the cylinder bore is tilted slightly forward. 4 to 6, the deep bottom portion 9b is higher on the exhaust side, but in reality, as shown in FIG. The bottom is horizontal.

The oil pan 1 is a die-cast product made of aluminum, and the inner surface is provided with a draft so as to expand upward. As shown in FIG. 6, the side wall 3 on the exhaust side is substantially parallel to the axis O2 of the cylinder bore, while the side wall 3 on the intake side widens upward with respect to the axis O2 of the cylinder bore. is slanted, the side wall 3 on the exhaust side is actually tilted forward with respect to the vertical line O3.

An oil drop hole is formed in the wall of the cylinder block 2 on the exhaust side. and flows to the bottom 9 of the oil pan 1.

(2) Reinforcing stepped portion As shown in FIGS. is formed along the entire length. For example, as can be understood from FIG. 2, the stepped reinforcing portion 24 is formed at a position slightly higher than the shallow bottom portion 9a of the bottom portion 9. As shown in FIG. Further, as shown in FIG. 1 , the stepped reinforcing portion 24 has a part formed by winding the longitudinal rib 11 . In FIGS. 1, 2, and 3, the stepped reinforcing portion 24 is hatched with parallel oblique lines to clarify its range.

As shown in FIGS. 1 and 3, the stepped reinforcing portion 24 is continuously formed with a front extending portion 24a that wraps around the inner surface of the front wall 5 and a rear extending portion 24b that wraps around the inner surface of the rear wall 7. ing. As shown in FIGS. 2 and 3, the front extension portion 24a has a height close to the lower end of the front overlapping surface 15 to which the front cover 4 is fixed. On the other hand, the rear extension portion 24b has a height that overlaps the rear overlapping surface 19 on which the transmission case 6 overlaps.

As clearly shown in FIG. 6, the side wall 3 is bent in a crank shape so that the upper portion across the stepped reinforcing portion 24 is located laterally outside the lower portion. Therefore, it exhibits high rigidity against an external force such as an external bending force in the vertical direction, an external force such as bending in the horizontal direction, or an external force such as twisting around the axis in the direction of the crankshaft center O.

In particular, in this embodiment, since the stepped reinforcing portion 24 is formed with the front extending portion 24a and the rear extending portion 24b, the rigidity against torsion is greatly improved. Further, the stepped reinforcing portion 24 is sufficient to change the shape of the peripheral wall of the oil pan 1, and the processing cost and weight do not increase.

In addition, as described above, the oil flowing down from the oil drop hole of the cylinder block 2 flows along the inner surface of the side wall 3 on the exhaust side. Since the temperature is lowered, the contact time and contact distance with the side wall 3 become longer, and the contained air bubbles are effectively dissipated.

The oil that functions as an oil jet for cooling the piston is blown off by the crank arm and counterweight and adheres to the side wall 3 on the exhaust side as indicated by arrow 25 . Since the stepped reinforcing portion 24 reduces the flow velocity, the diffusion of air bubbles is facilitated. Since the stepped reinforcing portion 24 increases the oil adhesion area, it can contribute to the improvement of the oil cooling performance.

In the embodiment, the stepped reinforcing portion 24 curved like a crank is used as the reinforcing portion, but it is also possible to use ribs projecting inwardly or outwardly or both inwardly and outwardly as the reinforcing portion. However, if the stepped reinforcing portion 24 is employed as in the embodiment, there is an advantage that even if the oil pan 1 is a die-cast product, it can be easily manufactured.

The present invention can be embodied in an oil pan for an automotive internal combustion engine. Therefore, it can be used industrially.

0 Crank axis 1 Oil pan 2 Cylinder block 3 Side wall 3a Upper surface of side wall 4 Front cover 5 Front wall 6 Transmission case 7 Rear wall 9 Bottom 9a Shallow bottom 9b Deep bottom 14 Gouged part 24 Stepped reinforcing part

Claims (1)

An oil pan for use in an internal combustion engine that is arranged in an engine room provided in the front part of a vehicle with the crankshaft center extending in the vehicle width direction and the side of the exhaust gas facing the forward direction of the vehicle,
It has a pair of side walls to which the cylinder block is fixed on the top surface, a front wall located on the side of the front cover that covers the timing chain, and a rear wall to which the transmission case is fixed, and an exhaust pipe passes through the bottom. A gouged portion is formed, so that the bottom portion has a shallow portion at the gouged portion and a deep portion at the front side of the gouged portion,
A stepped or rib-shaped reinforcing portion is formed on each of the side walls along the entire length of the side wall when viewed from the direction of the crankshaft, and a front extending portion extending around the front wall is formed at the front end of the side wall. While formed
The front cover is fixed to the front surface of the front wall, and the front extension part of the reinforcing part is set at a height that overlaps with or is close to the lower end of the front cover.
Oil pan for automotive internal combustion engines.

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