JP3194739B2 - Engine block structure - Google Patents

Description

The present invention relates to an engine block structure, and more particularly to an engine block structure in which a lower block is interposed between a cylinder block and an oil pan. .

<< Conventional Technology >> Generally, engine cylinder blocks are disclosed in
The crankshaft is rotatably supported inside thereof, and an oil pan is attached to a lower end thereof.

By the way, the lower end of the above-mentioned cylinder block is formed short to form a half skirt type, and a lower block is interposed between the cylinder block and the oil pan, and the lower block is integrally connected to each other. The lower block effectively suppresses the membrane vibration on both side walls of the block and the vertical vibration of the crankshaft.

That is, the lower block is provided with a plurality of ribs for fixing the bearing cap of the crankshaft straddling between both side walls and separated in the axial direction, and by coupling the bearing cap to the rib, The axial vibration of the bearing cap itself can be stopped at both side walls.

Further, a continuous transmission mounting flange is formed at one end of the lower block and the cylinder block, and a transmission is coupled to the transmission mounting flange to constitute a power plant.

<< Problems to be Solved by the Invention >> By the way, in such a power plant, it is known that an excessive bending force generated due to the operation of the engine is concentrated on a joint between the transmission and the engine block, and bending vibration is generated. There has been a problem that various adverse effects, for example, a muffled sound in a vehicle interior, are generated by the bending vibration.

Therefore, the generation of such bending vibration has a similar problem even in the engine block structure using the lower block, which can reduce the vibration mode of the engine block itself, and causes a problem between the transmission and the cylinder block and the lower block. It is desired to increase the stiffness.

Therefore, the present invention focuses on the fact that a rib for fixing the bearing cap of the crankshaft is provided on the lower block, and especially when tightening the fixing bolt inserted into the rib formed integrally with the end wall on the transmission mounting side. It is an object of the present invention to provide a block structure of an engine in which the generated stress is used to increase the rigidity of a joint with a transmission.

<< Means for Solving the Problems >> In order to achieve this object, the present invention provides a lower block between a cylinder block and an oil pan, and a transmission mounting flange continuous with one end of the lower block and the cylinder block. And a plurality of ribs for fixing the bearing cap of the crankshaft are provided axially separated from each other, and are formed so as to straddle between both side walls of the lower block. On a rib provided integrally with the end wall on the transmission mounting side so as to be located on the end wall, a fixing bolt insertion hole of a bearing cap is formed from both sides of the rib, and a boss portion of the fixing bolt insertion hole is formed in the lower block. Of the transmission mounting side end wall of the transmission mounting side. On the other hand, a reinforcing rib extending from the lower block side wall and the bottom wall is integrally formed with the transmission mounting end wall, and a part of the reinforcing rib is integrated with the outside of the cylindrical portion.

Here, the reinforcing rib is a rib extending in a vertical direction,
It is preferable that the vertical ribs intersect with the ribs so as to be integrated with each other, and that the upper ends of the vertical ribs are integrally connected to the outside of the cylindrical portion.

<< Operation >> In the engine block structure of the present invention having the above configuration, among the plurality of ribs for fixing the bearing cap, the fixing bolt insertion hole formed on the rib provided integrally with the transmission mounting end wall is provided. By tightening the fixing bolt, the tightening force acts on the cylindrical portion formed as the boss of the fixing bolt insertion hole.

Then, the stress generated by the tightening force at this time is
Acting on the reinforcing rib integrated with the cylindrical portion, the rigidity of the mission mounting side end wall of the lower block, on which the reinforcing rib protrudes, and thus the rigidity of the transmission mounting flange can be increased.

Therefore, the coupling strength between the engine block and the transmission can be increased.

<< Example >> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 to 4 show one embodiment of a block structure of an engine according to the present invention, and FIG.
FIG. 2 is a plan view of the lower block 12, FIG. 3 is a side view of the lower block 12, and FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. It is.

The lower block 12 is integrally formed as an aluminum die-cast, and is formed in a flat rectangular shape as shown in FIG. 2, and its side wall 12a is formed as a thin wall as shown in FIG. Upper and lower ends are provided with flanges 12b and 12c protruding outward.

A plurality of mounting holes 14 are formed in the upper flange 12b as shown in FIG. 2, and a lower end of the cylinder block 10 shown in FIG. Is combined with

One end (lower side in FIG. 2) of the cylinder block 10 and the lower block 12 is
A transmission mounting flange 16 that is substantially annularly continuous in a connected state with the lower block 12 is integrally formed, and a transmission (not shown) is bolted to the transmission mounting flange 16.

On the other hand, on the inside of the lower block 12, both side walls 12a, 12a
A rib 20 for fixing a bearing cap 18 (see FIG. 1) of a crankshaft (not shown) straddling between a is integrally formed.

As shown in FIG. 2, a plurality of the ribs 20 are provided in the axial direction (the axial direction means the axial direction of the crankshaft and is shown in the vertical direction in FIG. 2). Four ribs 20a, 20b, 20c, 20d from the lower end of the mission mounting side
Are spaced apart.

A rib 20e is provided between the ribs 20b and 20c. However, since the rib 20e is located at a central portion of the crankshaft having a small amplitude, a bearing cap is not provided.

As shown in FIG. 4, the four ribs 20a, 20b, 20c, 20d are provided with bolt insertion holes 22, 24 from the bottom direction and both sides, respectively, and are inserted through these bolt insertion holes 22, 24. The bearing cap 18 is fixed via fixing bolts 26 and 28. Bosses are formed around the bolt insertion holes 24, respectively.

Therefore, by fixing the bearing cap 18 to the rib 20 via the fixing bolts 26 and 28 in this manner,
The vibration in the longitudinal direction of the bearing cap 18 itself can be suppressed, that is, the film vibration of the block and the longitudinal vibration of the crankshaft, which is the vibration source, can be suppressed.

The reinforcing ribs 3 are provided on the outer side of the side wall 12a of the lower block 12.
0 is protruded, and the rigidity of the thin-walled side wall 12a is ensured.

Incidentally, an inner portion of the transmission mounting flange 16 formed in the lower block 12 is configured to be closed by a thin-walled transmission mounting-side end wall 12d, and at this time, the end wall 12d is 2 is formed flush with the upper end face in FIG. 2, and the lower end of the flange 16 in FIG. 2 is formed so as to protrude from the end wall 12d.

On the other hand, the rib 20a provided at the end of the transmission mounting side of the rib 20 is formed integrally with the end wall 12d so as to be located inside the end wall 12d of the transmission mounting side.

As shown in FIG. 2, a bottom wall 12e is formed at the bottom of the lower block 12, and the bottom wall 12e has a large opening at a central portion leading to the oil pan.

Here, in this embodiment, a cylindrical portion formed as a boss portion of the fixing bolt insertion hole 24 formed in the rib 20a
A part of 32 protrudes outward from the end wall on the transmission mounting side.

The cylindrical portion 32 is provided with the transmission mounting flange 16.
Are not projected from the mounting-side end face (the lower end face in FIG. 2).

Further, outside the mission mounting side end wall 12d, reinforcing ribs 34 and 36 extending from the both side walls 12a, 12a and the bottom wall 12e of the lower block 12 are integrally protruded, and provided vertically. The upper end of the reinforcing rib 34 is integrally connected to the outside of the cylindrical portion 32.

With the above configuration, in the engine block structure of the present embodiment, the rib 20
The fixing bolt insertion hole 24 in a
However, since the fixing bolt insertion hole 24 is formed in the cylindrical portion 32, the fixing bolt 2 for fixing the rib 20a and the bearing cap 18 is formed.
The cylindrical portion 32 can sufficiently withstand a large tightening force of eight.

The tightening force of the fixing bolt 28 inserted into the fixing bolt insertion hole 24 acts on the cylindrical portion 32, and the stress generated in the cylindrical portion 32 by the tightening force at this time causes the cylindrical portion 32
Acts on the reinforcing ribs 34 integrated with the ribs.

Then, the reinforcing ribs 34 and the reinforcing ribs 36 intersecting and integrated with the reinforcing ribs are in a state of tension by the stress, and the transmission mounting end wall 12 on which the reinforcing ribs are protruded is provided.
The rigidity of the transmission mounting flange 16 can be increased along with the rigidity of the end wall 12d.

Therefore, the rigidity of the coupling portion between the lower block 12 and the transmission is significantly increased, and thus the coupling rigidity of the entire engine block and the transmission is increased, and the bending vibration that is likely to occur in the relevant portion is significantly reduced. Can be.

<< Effects of the Invention >> As described above, in the engine block structure of the present invention, the fixing bolt insertion hole formed in the bearing cap fixing rib provided at the transmission mounting end is provided with the transmission mounting end. A part of a reinforcing rib formed on a transmission mounting side end wall by forming a side wall and a bottom wall of a lower block to be formed integrally with a cylindrical portion which protrudes from a wall integrally with the outside of the cylindrical portion. Because of this, the stress generated in the cylindrical portion by the tightening force when the fixing bolt is tightened into the fixing bolt insertion hole can act on the reinforcing rib.

For this reason, the rigidity of the end wall on the transmission mounting side of the lower block on which the reinforcing ribs are protruded, and hence the rigidity of the transmission mounting flange can be increased, and the coupling strength between the engine block and the transmission is greatly increased. can do.

Therefore, in the present invention, it is possible to enhance the rigidity-reduced portion of the joint portion between the engine block and the transmission, which has been a problem, and to suppress bending vibration of the portion, which is transmitted from the power plant to the vehicle body side. An excellent effect that vibration can be greatly reduced is exhibited.

[Brief description of the drawings]

1 is an exploded front view showing an embodiment of an engine block structure according to the present invention in an exploded state, FIG. 2 is a plan view showing an embodiment of a lower block used in the present invention, and FIG. FIG. 4 is a side view showing one embodiment of a lower block used in the present invention, and FIG. 4 is a sectional view taken along the line IV-IV in FIG. 10: Cylinder block 12: Lower block 12a: Side wall 12d: Mission mounting side end wall 12e: Bottom wall 16: Mission mounting flange 18: Bearing cap 20a: Rib 24: Fixing bolt insertion hole 28 …… Fixing bolt 32 …… Cylindrical part 34,36 …… Reinforcing rib

Claims (2)

(57) [Claims] A lower block is provided between a cylinder block and an oil pan, a continuous transmission mounting flange is formed at one end of the lower block and the cylinder block, and a straddle is provided between both side walls of the lower block. A plurality of ribs for fixing a bearing cap of a crankshaft are provided in the axial direction at a distance from each other, and the plurality of ribs are integrated with the end wall on the transmission mounting side so as to be located on the end wall on the transmission mounting side. A fixing bolt insertion hole for the bearing cap is formed in the rib provided from both sides of the rib, and a boss portion of the fixing bolt insertion hole is integrally bulged outward from the transmission mounting end wall of the lower block. And reinforcing ribs extending from the side wall and bottom wall of the lower block outward from the end wall on the transmission mounting side. Block structure of an engine is integrally projected and mission attached end wall, a portion of the reinforcing ribs, characterized in that is integrated with the cylindrical portion. 2. The reinforcing rib comprises a rib extending in the vertical direction and a rib intersecting the rib in the vertical direction and being integrated with the rib in the vertical direction. 2. The method as claimed in claim 1, wherein said first member is integrally connected to said first member.
Cylinder block for the described engine.