JPS5841247A - Cylinder block for engine - Google Patents

Abstract

PURPOSE:To reduce fricitional resistance for a piston as a whole and improve the mechanical efficiency of the engine by a method wherein the roughness of the surface of the cylinder is made rough at the location near the upper dead point of the piston to realize a boundary lubricating condition while the same is made smooth near the lower dead point of the piston to realize a fluid lubricating condition. CONSTITUTION:The surface of the cylinder 2 is formed so as to have a part 2a, having a rough surface roughness and located near the upper dead point of the piston wherein a piston speed is small and the pressure of gas in a combustion chamber is high, and the other part 2b, having a smooth surface roughness and covering an area from the center of the cylinder to the vicinity of the lower dead point of the piston wherein the piston speed is increased and the pressure of the gas is reduced. Further, the intermediate part thereof is formed as another part 2c. According to this constitution, the lubricating condition is brought into the boundary lubricating condition near the upper dead point, a mixed lubricating condition at the intermediate part, and the fluid lubricating condition near the lower dead point, therefore, said conditions are adapted to respective lubricating conditions determined in accordance with the piston speed as well as the pressure of the gas and the frictional resistance may be reduced as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to an engine cylinder ay that reduces the frictional force on the piston y in the entire area of the surface of the piston.
fP1゜As a conventional engine glue 11/der block.

For example, there is something like the one shown in ゛◆f No. 1 (“Internal Combustion Horizontal Opening Engineering” Child 11111F stock < 4HtQ line p 19), r
In Fig. t1 and w, 1 is a solid block, and a piston ys is provided in a cylinder 2 of this block 1 so as to be able to reciprocate, and a large piston ys is generated in the combustion chamber above the piston S. The piston S descends under pressure, and the concrete 4
V acts to move the crankshaft 5t' [f].

Forward, in such an engine, as shown in @2gA'
SKS top dead center. The speed of the piston 3 becomes zero at the point, and reaches its maximum at these intermediate strokes, and the combustion type gas pressure reaches its maximum near the top dead center of the compression explosion, as shown in Figure 5.

For this reason, the piston y3, the piston ring 6, and the cylinder 2 reach the speed of the piston yl (near the top dead center where the gas pressure is high) and approach each other through the lubricating oil Ov, and finally, the solid parts come into contact with each other in a part. do. A state of boundary lubrication as shown in FIG. 4 is created, and friction increases. As the piston 1 descends, the piston speed increases and the gas pressure decreases, causing the front boundary to drop.

piston! ! Then, the piston ring 6 and the cylinder y 2 are in an intermediate state between the fluid lubrication state and the boundary lubrication as shown in Fig. 5, in which there is sufficient lubricating oil, and i5 and K are To complete fluid lubrication! become Along with this, the frictional force is high near the top dead center (and decreases as it gets closer to the bottom dead center).

On the other hand, the constant (1) representing the lubrication conditions for the periphery bearing
It is known that the relationship between the coefficient of viscosity of the lubricating oil, N, rotational speed of the shaft, p and rolling load) and the coefficient of friction is as shown in 1III7 as a surface island. Lubrication J vol 2 s, A9.P
6Bm.

19711) The surface roughness is smooth (Omagari II)
'II K/p, nagging (high load, low rotation) III
I! Fluid lubrication is maintained in a blind state, and the friction coefficient is kept low, but when the 'II N/p ratio decreases and the lubrication conditions become severe, the friction coefficient suddenly increases due to the rapid transition from mixed lubrication to fluid lubrication. do. On the other hand, 0's surface is rough.

(peal)
Since the coefficient increases, the same ηN/pm-C' has a rough surface, but the frictional force increases). The smoother the am, the thicker the coefficient of friction.

In addition, the cylinder 9y 2, the piston ys and the piston ring 4
In the 1llI Seito matter, the t< is changed depending on the edge ygi load, the engine rotation, the piston y position, etc., so the piston series W, which determines the lubrication conditions, and the surface roughness t according to the gas pressure are uniformly selected. 2, the piston I%, and the frictional force between the piston ring 4 can be reduced.

However, in the conventional silinodarp ivy, the roughness of the surface of the cuff 2 was uniformly finished over the entire area in the vertical direction.

If the surface roughness -g is increased, the piston speed is slow and the frictional force is reduced near the top dead center where the gas pressure is high. The focus on lubrication increased, and the frictional force increased; on the other hand, when the surface roughness was reduced, the opposite relationship occurred, and it was not possible to reduce the frictional force.

The present invention focuses on the point between such W rice! The surface roughness of the cylinder y near the top dead center of the piston is set to Odate's boundary lubrication state, and near the bottom dead center the surface of the cylinder is clean and fluid lubrication is achieved. The object of the present invention is to create a series of engine blocks that are designed to increase the mechanical efficiency of the engine as well as the friction against the piston as a whole.

Embodiment t/Figure W of the present invention will be specifically described below.

The WL1 diagram takes rotational eccentricity as an example, and uses the above-mentioned specifics to determine the number of shaft revolutions y and shaft weight of a Veri bearing. It shows the friction characteristics with respect to mm oil viscosity η as -AK. KL decreases in N/Pa, so the formation of an oil film becomes difficult and % fluid lubrication becomes 1 go? In the boundary lubrication region, the friction coefficient becomes constant, regardless of the shaft rotational speed.

In addition, in the boundary lubrication region and mixed lubrication, the coefficient of friction varies depending on the surface roughness of the two objects undergoing friction.
If the surface roughness is large, boundary lubrication 11 II! tt is wide, but the surface roughness is small (i.e. the surface is clean)
The coefficient of friction is smaller than that during boundary lubrication.

That is, in area 3 of 1 vote and 7 figures.

If the surface is rough to some extent, the coefficient of friction will be smaller.

On the other hand, if the surface roughness is smooth, the fluid skin area will be wide, and if the surface f is rough, the friction coefficient will be smaller than the coefficient of friction during boundary lubrication of the spear. In other words, if one surface is smooth in region C of Figure 7, the friction coefficient will be small.

However, when the piston S is at 11 near the top dead center, the building is hy! Because the speed of I is low and the gas pressure of the combustion seal is high, the conditions for cleaning are severe and the boundary 111I is in a slippery state. - 10,000, piston S is T from near the center of cylinder 2
As the speed of the piston 3 increases (and the load decreases), the speed of the piston 3 becomes slower and the speed changes from 1st lubrication to fluid lubrication.

(Then, the X point of line 711 is the boundary KL, and the surface roughness of the cylinder 20 of cylinder 20 of al is mv, as shown in FIG. 6 (b). W.A.
Then, the lower inner surface S is made into a portion 2b with a small surface roughness, and a fluid clearing state llK is obtained. In addition, the intermediate part of these parts is made into a mixed lubricant with 1/2c of its intermediate roughness.
Therefore, there are summer screws in the entire area between the top and bottom of cylinder 2.
Reduces the friction force against the ) yr> Yokoyari Kashasha can do the same as above.

In addition, the surface roughness is extremely smooth. Since the position at which the piston S becomes R varies depending on the speed of the piston S (engine speed) and the gas pressure (engine negative RR), it cannot be determined unambiguously. (It will be decided by this.

In addition, 1 ift of the surface roughness of the cylinder 20 is the roughest (even α
♂,c+mRa (,Trs)sI! , it is desirable to select them so that even if they are the cleanest on the smooth side on the bottom dead center side, they have a slope of α1.

The method for manufacturing the cylinder 2 having the above structure is as follows.

After honing the entire length of cylinder 2 with rough hoening in two or more steps, finish honing the lower half w#c, and then finish honing the upper half of cylinder 2.
and the wear resistance of the lower part 2b [l! By increasing the wear resistance of the upper part 2a, it is possible to prevent the formation of a rough surface similar to that described above during sliding of the Bistono S.

As explained above, according to the present invention, in an engine in which the piston 7 reciprocates in the cylinder circle, the cylinder surface roughness t is rough near the top dead center (and smooth on the boundary side @K L
By clearing the fluid 1111 near the bottom dead center and making it into the shape of the fluid 1111, the eclipse area K of the cylinder where the piston moves back and forth [that is, the frictional resistance Kt of the cylinder y on this piston]
'It has a low power, so it is possible to improve the efficiency of the horizontal spear of the edge.

[Brief explanation of the drawing]

Figure 11i is a cross section of a conventional engine, Figure 2 is a speed characteristic diagram of the engine, and Figure S is a gas pressure characteristic diagram of the combustion chamber.
@4 Figure is an explanation of boundary lubrication 811. Figure 5 is an explanation of fluid lubrication a! 11. FIG. 6(a) is a partially cutaway cross section of the silicate in the present invention! g1%1% (b) is a detailed cross-sectional view of the main part, and FIG. 7 is a f411 characteristic diagram showing the relationship between surface roughness and friction coefficient. 2...Cylinder! ...Piston, 2m...Large part with rough surface, 2t)...Part with small surface roughness. Figure 1

Claims (1)

[Claims] In an engine in which the cylinder/inner piston moves reciprocally, the cylinder surface is roughened at and near the top dead center of the piston to provide boundary lubrication. Use the engine cylinder plotter to clean and smooth the fluid.