JPH0629487Y2 - Engine cylinder block reinforcement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a cylinder block reinforcing device for an engine, in which main bearing caps are integrally connected to each other to increase the rigidity of the main bearing caps and the cylinder block skirt portion. .

(Prior Art) In a cylinder block of an automobile engine, a main bearing cap is usually connected to each main bearing portion at the center of the lower end, and an oil pan is attached so as to cover the entire bottom surface of the block including these main bearing caps. To be However, with such a block structure in which the main bearing caps are individually attached, it is difficult to secure the rigidity of the main bearing cap and the cylinder block skirt portion against combustion gas pressure and inertial force when the engine has high output. Become. Therefore, as disclosed in, for example, Japanese Patent Laid-Open No. Sho 60-219436, there is proposed a lower block in which each main bearing cap is integrally connected and is connected to the lower end of the cylinder block. Has been done.

By the way, the cylinder block has another important problem of weight reduction in parallel with the problem of ensuring its rigidity. However, the structure of the conventional lower block including those described in the above publications is The contradictory problems of securing the rigidity of the cylinder block and promoting the weight reduction cannot be sufficiently achieved. Also, when connecting a lower block of this type to the lower end of the cylinder block, it is necessary to provide a blow-by gas ventilation passage so as to pass through the side portion of this lower block and open to the oil pan side.
If the swing of the oil level in the oil pan is large at the time of starting or climbing a slope, there is a problem that the opening of the blow-by gas ventilation passage is blocked by the oil and the blow-by gas ventilation passage does not function normally.

(Purpose of the Invention) The present invention has been made in view of the above problems, and in particular, the weight of the main bearing cap portion is increased while the weight is reduced, and the blow-by gas ventilation passage is prevented from being blocked by the oil surface. The purpose is to ensure blow-by gas ventilation performance.

(Structure of the Invention) The present invention devises the wall structure of the cylinder block reinforcing device having the structure in which the main bearing caps are connected, and in particular, achieves the above object by arranging an arc-shaped bottom wall and effective ribs. It was realized, and its configuration is as follows.
That is, in the engine cylinder block reinforcing device of the present invention, in the engine cylinder block reinforcing device of the engine in which the main bearing cap portions are integrally provided and are connected between the cylinder block and the oil pan, The bottom wall to be connected has an arcuate shape along the crank locus, and a rib is formed on the outer peripheral surface of the bottom wall so as to project in the direction in which the explosive load acts and extends in the crankshaft direction. In addition, an opening of the blow-by gas ventilation passage is provided at a position on the outer side of the rib, and the amount of protrusion of the rib in a portion located in the vicinity of the opening is made smaller than the amount of protrusion of other portions. There is.

(Operation) Explosive load of the engine and inertial force of the piston are deformed by tilting vibration in the front-back direction (crank axis direction) to the main bearing cap through the crank shaft, twisting around the crank shaft, and bending around the cylinder bore axis. Although acting as an exciting force that induces vibration, the main bearing cap portions are connected to each other by an arcuate bottom wall, and the outer peripheral surface of the bottom wall is in the direction in which an explosive load acts. Since ribs that project and extend in the crankshaft direction are formed, the ribs have high rigidity against the above-mentioned tilt vibration and deformation vibration.

Further, the rib serves as a weir when the oil level in the oil pan swings at the time of starting or climbing a slope, and suppresses the swing from increasing. As a result, the opening of the blow-by gas ventilation passage provided on the outer side of the rib is prevented from being blocked with oil. Further, since the rib protrusion amount is small in the vicinity of this opening, the blow-by gas ventilation passage and the entire crank chamber are communicated with each other by the rib when the oil surface is inclined while suppressing the oscillation of the oil surface as a whole. Can be prevented from being blocked, which ensures ventilation of the entire crankcase.

(Example) Hereinafter, an example will be described with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention applied to a V-type 6-cylinder engine. FIG. 1 is a bottom view of a cylinder block reinforcing device of the embodiment, and FIG. First
It is an AA sectional view of the figure (however, the state which attached the oil pan is shown.).

In this embodiment, a lower block 1 which is connected to a lower end surface of a cylinder block (not shown) and functions as a cylinder block reinforcing device includes a plurality of main bearing cap portions 3 each having a cast iron cap 2 and these main bearing caps. Part 3
A side wall 4 that connects the side surfaces of the main bearing cap portions 3 to each other to define a crank chamber inside, and a bottom wall 5 that connects the main bearing cap portions 3 to each other. The bottom walls 5 are formed in an arc shape along the rotation locus of a crankshaft balancer or a large end of the connecting rod (not shown), and a substantially rectangular opening 6 is provided at the center of each bottom wall 5. . An oil pan 8 is attached to the flange portion 7 at the lower end of the side wall 4 of the lower block 1 as shown in FIG. Further, the lower block 1 is provided with a pair of fixing bolt holes 9 at symmetrical positions of each main bearing cap portion 3, and outside the bolt hole 9, the connecting position of each main bearing cap portion 3 and each A fixing bolt hole 10 having a slightly smaller diameter is provided in the middle of the connecting position.
The lower block 1 is connected to the cylinder block by fixing bolts (not shown) using the bolt holes 9 and 10.

On the outer peripheral surface of the bottom wall 5 of the lower block 1, ribs 11a and 11b projecting downward and extending in the crankshaft direction are provided at symmetrical positions. Further, the lower block 1 is provided with a pair of left and right blow-by gas ventilation passages 12 a along the inside of the side wall 4. This ventilation passage 12a
In the present embodiment, is a passage for introducing fresh air (intake air upstream of the throttle valve) into the crank chamber. The blow-by gas ventilation passages 12a have openings 13a provided outside the outer circumference of the bottom wall 5 and outside the left and right ribs 11a and 11b. In addition, a pair of left and right ribs 11a, 1
A recess 14 is formed in 1b so that the amount of protrusion of the portion of the blow-by gas passage 12a located near the opening 13a is smaller than the amount of protrusion of other portions.

At the position along the inside of the side wall 4 of the lower block 1,
Oil return passages 12b are provided on the left and right, and openings 13b are formed in the oil return passages 12b. Oil return passage 12b
Is a passage for collecting the oil in the valve operating chamber of the cylinder head (not shown) to the oil pan 8.

The lower block 1 of this embodiment has an integral structure in which the main bearing cap portion 3 having the cast iron cap 2 is connected by the side wall 4 and the bottom wall 5 as described above, and
The bottom wall 5 provided so as to avoid the crankshaft locus has a highly rigid arc shape. Therefore, the side wall 4 and the arc-shaped bottom wall 5 mutually support each other to enhance the rigidity of the main bearing cap portion 3 and reduce the tilt vibration and the deformation vibration such as torsion or bending. Further, the rigidity of the lower block 1 including the main bearing cap portion 3 is further enhanced by the pair of left and right ribs 11a and 11b.

Further, the bottom wall 5 itself functions as a baffle for suppressing the rocking of the oil in the oil pan 8, but the pair of left and right ribs 11a and 11b are provided, so that the effect of suppressing the oil rocking is further enhanced. ing. In particular, when the oil rocks when starting or climbing a hill, the left and right ribs 11
a and 11b act like a weir to stop the oil.
Therefore, the openings 1 of the left and right blow-by gas passages 12a
3a is prevented from being blocked by oil. Also,
At the position close to the opening 13a of the blow-by gas passage 12a, the recesses 14 are provided in the ribs 11a and 11b. Therefore, even if the oil surface is inclined to the position shown by the phantom line in FIG. 12a and ribs 11a, 1
It is kept in communication with the inside of 1b. Therefore, it is possible to sufficiently secure a passage for introducing the fresh air from the blow-by gas passage 12a into the oil pan 8 and supplying the fresh air to the crank chamber of each cylinder through the opening 6 of the bottom wall 5.

As described above, the lower block 1 includes the main bearing cap portion 3, the side wall 4, the arc-shaped bottom wall 5, and the ribs 11a and 11b.
Since it has a thin-walled structure, it does not increase the weight of the engine.

The present invention can be applied to engines other than the V type.

(Effect of the Invention) Since the present invention is configured as described above, it is possible to increase the rigidity of the main bearing portion without increasing the weight of the engine, and moreover, to introduce fresh air or blow-by gas through the blow-by gas ventilation passage. The blow-by gas ventilation performance can be secured by preventing the flow of oil from being obstructed by the oil surface.

[Brief description of drawings]

1 is a bottom view of a lower block according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA of FIG. 1: Lower block, 2: Cast iron cap, 3: Main bearing cap part, 5: Bottom wall, 8: Oil pan, 11a, 11
b: rib, 12a: blow-by gas ventilation passage, 13a:
Opening, 14: hollow.

Claims (1)

[Scope of utility model registration request] 1. A cylinder block reinforcing device for an engine, wherein each main bearing cap portion is integrally provided and connected between a cylinder block and an oil pan, and a bottom wall connecting each main bearing cap portion is formed along a crank locus. And a rib projecting in the direction in which the explosive load acts and extending in the crankshaft direction are formed on the outer peripheral surface of the bottom wall, and at the outer side of the outer periphery of the bottom wall and on the outer side of the rib. An engine cylinder block reinforcing device for an engine, wherein an opening of a blow-by gas ventilation passage is provided at a position, and a protruding amount of the rib in a portion located in the vicinity of the opening is made smaller than a protruding amount of other portions.