JPS6065255A - Engine cylinder block - Google Patents

Abstract

PURPOSE:To reduce the weight by reducing the rigidity of second and fourth bearings of series four cylinder engine in the direction perpendicular with the axis with respect to other bearings. CONSTITUTION:The cylinder block 1 is constructed with cylinder section 2, lower deck section 5 at the lower end of cylinder section 2 and skirt section 6 opening to the opposite sides of lower deck section 5. The first to fifth bearings 3A-3E are coupled through coupling sections 4A-4E to the lower deck section 5 and skirt section 6. Here, the rigidity of the coupling sections 4B, 4D of the bearings 3B, 3D are provided with reinforcing effect in up/down direction through reinforcing ribs extending upward from the opposite sides and upper portion of bearings 3B, 3D while the rigidity in the left/right direction is set lower than these of the coupling sections 4A, 4C, 4E to be coupled to the bearings 3A, 3C, 3E.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to the structure of a cylinder block in an in-line four-cylinder engine.

(Prior art) In general, the cylinder block of an in-line four-cylinder engine supports the crankshaft with a total of five bearings, so that the crankshaft is supported on both sides of each cylinder. The parts are connected to the skirt part and the lower deck part through connecting parts, respectively, and are configured so that the load acting on the bearing part is supported by the connecting parts.

However, various reinforcement structures for the above-mentioned connecting parts have been proposed as seen in Japanese Utility Model Application Laid-Open No. 57-178151 as the weight of engines has been reduced. They have the same reinforcement structure, and a structure based on differences in the loads acting on each part is not adopted. Therefore, there are problems in that there are parts where extra rigidity impedes weight reduction, or where lack of rigidity causes vibration noise at high loads and high rotations.

(Objective of the invention):' □ In view of the above circumstances, the present invention analyzes the loads acting on each bearing part of an in-line, 4-cylinder engine, adopts an effective reinforcing structure corresponding to the difference, and provides sufficient reinforcement. The object of the present invention is to provide a cylinder block for an in-line four-cylinder engine, which reduces noise during high loads and high rotations by imparting sufficient rigidity, and which is lightweight by removing excess rigidity.

That is, as shown in the schematic structure □ in Fig. 1, the cylinder block 1 of an in-line four-cylinder engine has:, screws! -n10
The crankshaft 9 is placed below the cylinder part 2 that accommodates the cylinders 1A to 1D and constitutes the first to fourth cylinders 1A to 1D.
The first to fifth supports each at five locations on both sides of 1D.
Bearing portions 3A to 3E are provided.

The loads that act on each of the bearings 3A to 3F due to the operation of the engine are rotational inertia force, reciprocating inertia force, and cylinder pressure. The figure shows the variation characteristics of the crankshaft (direction perpendicular to the respective axes of the crankshaft, the cylinder shaft, and the cylinder axis) with respect to the crank angle.

Figure 2 A shows the rotational inertia force, and the rotational inertia force A in the vertical direction
1 is a sine curve that shows the maximum value at top dead center T and the minimum value at bottom dead center B when the upward force is positive, and on the other hand,
The rotational force A2 in the left and right direction has a variation with a phase shift of 90 degrees with respect to the variation in the vertical direction, with the force in the right direction being plus.

FIG. 2B shows the reciprocating inertial force (-order component), in which the reciprocating inertial force B1 in the vertical direction is the same as the rotational inertial force A1, and the reciprocating inertial force B2 in the left-right direction is zero.

Figure 2C shows the pressure in the cylinder, where the cylinder pressure in the vertical direction C1 is affected by the large explosion pressure acting in the negative direction near the compression top dead center, and the cylinder pressure in the left and right direction C2
becomes zero.

If the ignition order is 1-3-4-2, the above loads are 540 degrees off for the 2nd cylinder and 1 for the 3rd cylinder.
They occur with a phase shift of 80 degrees and a phase shift of 360 degrees in the fourth cylinder.

As a result, the first bearing part 3A□ has the load generated by the first person i'2m receiving part 38'1. knee.

is generated by the first cylinder 1A and the second air a I B
The load generated by the second cylinder 1B and the third cylinder 1d acts on the 3'@ bearing part '3'C axis, and the fourth bearing part '3D (is affected by the load generated by the 3rd cylinder 1C axis). The loads generated by □ and the fourth cylinder 16 act, and the i5 bearing portion 3
Since the load generated by t due to the 4th mm1'o acts on F, the 'WJ weight of the vertical and horizontal components in each bearing part 3A-bi is as shown in the diagram =g□
. In this case, when the difference in cylinder pressure is set to 1,
The rotational force and the reciprocating inertial force are approximately 0.5 times larger. 1. As for the 9th balance type crankshaft, a fully balanced type would be heavier and larger, so we are using an imperfectly balanced type. ' □ ・ Figure 3 a' to e are in order from 1st to 5th Edict 3A~
3F, and as is clear from this figure, the load in the left and right direction is applied to the second and fourth bearing parts 3B' and 3F.
It was found that the value was very small (zero) at D, the largest at the third bearing portion 3C, and intermediate values were shown at the first and fifth bearing portions 3A and 3'E'.

Based on the above analysis, in the present invention, we have changed the resistance number in the left-right direction (direction perpendicular to the respective axes of the crankshaft and cylinder shaft) of the connecting parts that connect to each bearing part.゛rumo□noadeki. □ ′′ (Structure of the invention □)
The cylinder block of the Endan according to the present invention consists of bearing parts that support the crankshaft of an in-line four-cylinder engine at five locations and are connected to the skirt part and the lower deck part through connecting parts, respectively. The rigidity in the direction perpendicular to the respective axes of the crankshaft and cylinder shaft of the connecting portion connected to the second and fourth bearing portions is determined by the stiffness of the connecting portion connected to the first, third, and fifth bearing portions. This is characterized in that the rigidity is set smaller than the rigidity of the section in the above direction.

(Effects of the Invention) In the connecting portion connected to the second and fourth bearing portions, the load in the left and right direction that acts with the operation of the engine is small,
By setting the rigidity in the direction orthogonal to the respective axes of the crankshaft and cylinder shaft, that is, in the left-right direction, to be smaller than the rigidity in the left-right direction of other bearing parts, the rigidity of the connecting part can be effectively increased. This makes it possible to reduce the generation of vibration and noise even under high loads and high rotations, and also to reduce weight by eliminating unnecessary rigid structures.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

4 is a cross-sectional view of the cylinder block taken along the line rv-rv in FIG. 1, showing the structure of the connecting portion for the first and fifth bearings, and FIG. 5 is a cross-sectional view of the cylinder block taken along the line V-v in FIG. A cross-sectional view of the block shows the structure of the connecting part to the second and fourth bearing parts, and FIG. 6 is a cross-sectional view of the cylinder block taken along the line Vl-Vl in FIG. 1, showing the structure of the connecting part to the third bearing part. It shows.

In the cylinder block 1 in each figure, 2 is a cylinder part,
Reference numeral 5 indicates a lower deck portion at the lower end of the cylinder portion 2, and 6 indicates a skirt portion extending on both sides of the lower deck portion 5. Each of the bearing portions 3A to 3E is connected to the lower deck portion 5 and the skirt portion 6 via connecting portions 4A to 4F. ing.

The rigidity of the first and fifth connecting portions 4A and 4E shown in FIG.
The reinforcing ribs 7a extending diagonally upward and on both sides of the bearing portions 3A, 3E have a reinforcing effect in both the vertical and horizontal directions, and the connecting portions 4A, 4
The portion of E other than the reinforcing rib 7a is formed into a thin wall portion 8.

The rigidity of the second and fourth connecting portions 4B and 4D shown in FIG.
The reinforcing ribs 7b extending upward from both sides of the bearing portions 3B and 3D and from the soil portion mainly provide a reinforcing effect in the vertical direction and reduce the rigidity in the left-right direction.

The rigidity of the third connecting portion 4c shown in Figure 6 is determined by the reinforcement ribs 7a and 7b shown in Figures 4 and 5 above, which have a large reinforcing effect in both the vertical and horizontal directions It has a meaning.

With the above structure, the rigidity in the left and right direction of the connecting parts 4B and 4D connected to the second and fourth bearing parts 38 and 30 is the same as that of the first and third bearing parts.
, fifth bearing portions 3A, 3C, 3E1. : It is set smaller than the rigidity in the left and right direction of the connecting parts 4A and 40.4F to be connected.

Therefore, the reinforcement structure of the connecting parts 4B and 4D connected to the second and fourth bearing parts 38, 30 can be simplified and the eaves can be expanded, and the other bearing parts 3A.

For 3G and 3D, the necessary reinforcement is also performed in the left and right directions to ensure that necessary and sufficient rigidity is obtained without generating noise-causing vibrations even under high loads and high rotations. .

Note that the structure of each connecting part is not limited to the structure of the thin wall part and reinforcing ribs in the above embodiment; for example, the rigidity in each direction can be changed by setting the location and shape of the opening in the connecting part in various ways. It may be provided in a structure that makes it variable,
Other reinforcing structures may also be adopted as appropriate.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing the structure of the syringe 10/ink section of an in-line 4-cylinder engine. Fig. 2 A, B, and C show the vertical and horizontal components of rotational inertia, reciprocating inertia, and cylinder pressure, respectively. Characteristic diagrams showing the components, Figures 3a to 3e are diagrams that do not show the magnitude of the loads in the vertical and horizontal directions at the first to fifth bearing parts, respectively, and Figure 4 is a diagram showing the characteristics of the engine according to an embodiment of the present invention. IV-IV in Fig. 1 showing the specific structure of the cylinder block
FIG. 5 is a cross-sectional view taken along line V--V in FIG. 1, and FIG. 6 is a cross-sectional view taken along line Vl--Vl in FIG. 1. 1...Cylinder block 1A-1D...Cylinder 3A-3F...
Bearing parts 4A to 4E... Connection part 5... Lower deck part 6... Skirt parts 7a, 7b... Reinforcement rib 9... Crank Axis tIIi 1 112Figure 3 (0) (b) (c) (d) (e) @6 Sound

Claims (1)

[Claims] (1) The bearing part that supports the crankshaft at five locations is
A cylinder block for an in-line four-cylinder engine, which is connected to a skirt part and a lower deck part through a connecting part, and each of the crankshaft and cylinder shaft of the connecting part is connected to a second and fourth bearing part. A cylinder block for an engine, wherein the rigidity in the direction perpendicular to the axis is set to be smaller than the rigidity in the direction of the connecting portion connected to the first, third, and fifth bearing portions.