JPS6327082Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cylinder block for an internal combustion engine.

The cylinder block of a conventional internal combustion engine is
For example, there are those shown in FIGS. 1 and 2. In FIG. 1, 1 is a main body of a cylinder block, and this main body 1 is provided with a cylinder chamber 2 in which a piston (not shown) slides in the vertical direction. An arcuate skirt portion 4 is provided on the lower deck 3 of the main body 1, and a thick semicircular crankshaft bearing portion 5 is disposed at the center of the arc of the skirt portion 4. The crankshaft bearing portion 5 is connected to the lower deck 3 and the skirt portion 4 by a thin plate-shaped bulkhead 6, respectively. Also,
The crankshaft bearing portion 5 is connected to the lower deck 3 by thick ribs 7 and 8, and the ribs 7 are provided with oil holes 9. This oil hole 9 communicates between an oil gear rally 10 provided in the lower deck 3 and the crankshaft bearing portion 5. A bearing cap 11 is located on the underside of the crankshaft bearing 5.
is tightened and fixed with bolts 12, and a crank journal 14 of the crankshaft is rotatably supported by a cylindrical portion 13 formed by the crankshaft bearing portion 5 and the bearing cap 11 via a main bearing (not shown). . The piston is connected to the crank pin of the crankshaft via a connecting rod (both not shown).

However, in such a conventional cylinder block, although the ribs 7 and 8 improve the bending rigidity of the bulkhead 6,
Since the bulkhead 6 is in the form of a thin plate, the bending rigidity of the bulkhead 6 and the tensile rigidity within the plane of the bulkhead 6 are not sufficient. Therefore, cylinder chamber 2
When the combustion impact force generated within the crankshaft is transmitted to the crankpin via the piston and connecting rod (both not shown), the crankshaft deflects in an arcuate manner. As a result, the bearing cap 11 supporting the crank journal 14 undergoes bending deformation, and the bulkhead 6 undergoes a large bending deformation together with the bearing cap 11, and at the same time, the bulkhead 6 is extended downward. The imaginary line in FIG. 2 shows this state. As a result of this phenomenon being repeated during operation of the internal combustion engine, the cylinder block body 1 is vibrated, causing a problem in that the radiated noise of the engine is increased.

This idea was created by focusing on these conventional problems.The wall thickness of the bulkhead is approximately the same as the width of the bearing cap, and a space is formed inside the bulkhead at least above the crank journal. The purpose of this invention is to solve the above-mentioned problems.

This invention will be explained below based on the drawings.

FIGS. 3 to 6 are diagrams showing an embodiment of this invention. First, the configuration will be explained. 21 is the main body of the cylinder block, and this main body 21 is provided with a cylinder chamber 22 in which a piston (not shown) slides in the vertical direction. A lower deck 23 of the main body 21 is provided with an arc-shaped skirt portion 24, and one end of a bulkhead 25 is connected to the lower deck 23 and skirt portion 24. A bearing cap 26 is fastened to the other end of the bulk head 25 with bolts 27, and a crank journal 29 is connected to the cylindrical portion 28 formed by the other end of the bulk head 25 and the bearing cap 26 via a main bearing (not shown). is rotatably supported. The piston is connected to the crank pin of the crankshaft via a connecting rod (both not shown). The bulkhead 25 is formed so that its wall thickness is approximately the same as the width of the bearing cap 26, and there are spaces 30, 31, 32 inside the bulkhead 25 that open at the other end of the bulkhead 25.
is formed. Space 30 is bolt attachment part 3
3 and 34, and spaces 31 and 32 are provided between the bolt attachment parts 33 and 34 and the skirt part 24, respectively. As a result, the space 30 is provided above the crank journal 29.
Moreover, the cross section of the space 30 is rectangular. One end of the bolt attachment parts 33 and 34 is connected to the bearing cap 26 with a bolt 27, and the other end is directly connected to the lower deck 23. As a result, the moment of inertia of the bulkhead 25 is improved without increasing its weight, so that the bending rigidity of the bulkhead 25 is improved. Furthermore, since the bolt attachment parts 33 and 34 are directly connected to the lower deck 23, the tensile rigidity within the plane of the bulkhead 25 is significantly improved. In addition, bulkhead 25
Since one end is connected across the entire skirt portion 24, the bulkhead 25 and the skirt portion 24 are connected to each other.
Improves the rigidity of the connection. In addition, the bolt mounting part 3
4 is provided with an oil hole 35, and this oil hole 35 communicates between the oil gear gallery 37 and the space 30.

Next, the action will be explained.

As shown in FIG. 2, the bulkhead 25 undergoes bending deformation due to the combustion impact forces occurring within the cylinder. However, since the moment of inertia of the bulkhead 25 has been improved, this bending deformation is reduced. Further, since the tensile rigidity within the plane of the bulkhead 25 has been significantly improved by the bolt attachment portions 33 and 34, downward expansion of the bulkhead 25 is suppressed. As a result, the bending rigidity and tensile rigidity of the bulkhead 25 as a whole are significantly improved, the vibrations of each part of the cylinder block are suppressed, and the radiated noise of the engine is significantly reduced.

Furthermore, FIGS. 7 to 9 are diagrams showing other embodiments of this invention. In this embodiment, a space 44 is provided between the bolt attachment parts 41 and 42 and the skirt part 43.
45 and spaces 46 and 47 are formed. The spaces 45 and 47 are open to the other end of the bulkhead 25, and the spaces 44 and 46 are open to the skirt portion 43 side. According to this embodiment, in addition to reducing the weight of the bulkhead 25, the curvature of the skirt portion 43 can be increased, and the bending rigidity of the bulkhead 25 can be improved. bulk head 25
The tensile rigidity is the same as in the first embodiment.

As explained above, according to this idea,
The thickness of the bulkhead is approximately the same as the width of the bearing cap, and a space is formed inside the bulkhead at least above the crank journal, thereby improving the bulkhead's moment of inertia and tensile rigidity. can be done. As a result, the vibrations of each part of the cylinder block are suppressed, and the radiated noise of the engine can be significantly reduced.

[Brief explanation of the drawing]

1 and 2 are a sectional view and a partially sectional side view showing a conventional cylinder block, FIG. 3 is a partially sectional side view showing an embodiment of this invention, and FIG. 5 is a cross-sectional view taken along line B-B of FIG. 3, FIG. 6 is a bottom view of the cylinder block shown in FIG. 3, and FIG. 7 is another implementation of this invention. Partial cross-sectional side view showing an example, No. 8
The figure is a sectional view taken along the line CC in FIG. 7, and FIG. 9 is a sectional view taken along the line DD in FIG. 7. 21... Cylinder block body, 25... Bulk head, 26... Bearing cap, 29...
...Crank Journal, 30...Space.

Claims (1)

[Scope of utility model registration request] In a cylinder block for an internal combustion engine, a crank journal is rotatably supported by a bulk head provided on the cylinder block body and a bearing cap that is tightened and fixed to the bulk head. Cylinder blocks for an internal combustion engine, which are substantially identical to each other, and are characterized in that a space is formed inside the bulkhead at least above the crank journal.