JPS6056151A - Cylinder block of water-cooled type engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder block for a water-cooled engine, and particularly to a cylinder block in which a cylinder sleeve made of wear-resistant material is provided on the inner circumference of the cylinder.

In recent years, in order to reduce the weight of engines, the cylinder block body has been made of a light alloy with low specific gravity, especially aluminum alloy, and an annular cylinder sleeve made of highly wear-resistant cast iron or the like is attached to the inner circumference of the cylinder. Cylinder blocks that have been modified are starting to be seen. The method of manufacturing such an aluminum alloy cylinder block is to assemble the cylinder sleeve casting material into the cylinder block mold, and then mold the sleeve by die casting, which involves injecting molten aluminum alloy under high pressure. There is a method of machining the inner periphery of the casting to a predetermined size after cooling.

However, when such a die-casting method is used, the outer circumference of the sleeve to be cast has a thickness of 800 to 1000.
A high pressure of kg/crn' is applied, and the molten metal solidifies under the high pressure, so that a large residual stress remains in the sleeve upon completion of solidification. Therefore, even if the inner periphery of the sleeve is machined to be a perfect circle after cooling, the residual stress will be partially released when exposed to high temperatures due to combustion heat during engine operation. In the case of a sleeve with a small wall thickness, the inner periphery may be deformed into a complicated shape.

Moreover, the deformation tends to be accelerated by the cooling/heating cycle caused by starting and stopping the engine.

In addition, when manufacturing a cylinder block with a water jacket by such a die-casting method,
A mold must also be used for the core to mold the water jacket, and in order to be able to pull out the core after molding, the water jacket must be assembled with a radial gasket into the cylinder. It has to be an open deck type with an opening on the deck surface.For this reason, on the deck surface side, the cylinder wall around the cylinder and the outer wall of the cylinder block are separated by a large gap. The rigidity of the cylinder wall in the vicinity of the surface decreases.This portion receives a particularly large thermal load during engine operation, and therefore, if the rigidity is small, thermal deformation becomes significant.

If the inner circumference of the cylinder sleeve deforms in this way, it will not fit well with the piston ring, increasing friction and increasing fuel consumption, or creating a gap that causes engine oil in the crankcase to be sucked into the combustion chamber. This can lead to an increase in oil consumption and a decrease in output due to deterioration in combustion.
Furthermore, the slap sound may increase.

In addition, in such a cylinder block, since the water jacket is provided on the aluminum alloy part, there is an interface between the cylinder sleeve made of cast iron or the like and the cylinder block body made of aluminum alloy between the water jacket and the cylinder. become. Since voids inevitably occur at such interfaces, these interfaces impede good heat transfer and reduce heat dissipation from the cylinder.6 The present invention was made in view of the above-mentioned circumstances. Even when the cylinder sleeve is cast using the die-casting method, the residual stress at the inner circumference of the sleeve is reduced, its thermal deformation can be reduced, and cooling performance is also improved. Its main purpose is to obtain cylinder blocks.

In order to achieve this object, in the present invention, the cylinder sleeve is configured as a double-structured sleeve having an inner wall and an integral outer wall, and the space between the inner wall and the outer wall is used as a water jacket. It is characterized by the fact that

In a preferred embodiment of the present invention, the inner and outer walls of the cylinder sleeve are integrally connected at the deck surface where the rad gasket is assembled to the cylinder, and the water jacket is of a closed deck type, thereby increasing the rigidity of the sleeve. I'm trying to increase that.

In the case of a multi-cylinder engine, the cylinder sleeves of adjacent cylinders are integrated so that their respective inner walls are connected to each other, thereby reducing the spacing between each cylinder and making the engine more compact. There is.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

1 to 3 show an embodiment in which the present invention is applied to a cylinder block of a multi-cylinder engine. FIG. 1 is a partially cutaway plan view, and FIGS.
FIG. 3 is a cross-sectional view taken along the line ■-■ and the line ■-■ in the figure.

As shown in FIG. 1, the cylinder block B includes a plurality of cylinder sleeves 1.1.1 arranged in series. . . . and a base material surrounding the outer periphery of the cylinder sleeves 1, 1° . . . , that is, a cylinder block body 2. The cylinder sleeve 1 is made of cast iron with high wear resistance, and the cylinder block body 2 is made of an aluminum alloy with low specific gravity.

As is clear from FIGS. 1 and 2, the cylinder sleeve l includes a cylindrical inner wall 11 forming each cylinder C,
An outer wall 12 surrounding the inner wall 11 at a distance from the inner wall 11
It has

The inner wall 11 and the outer wall 12 are integrally connected at a lower end 13, and further integrally connected at an upper end by a top wall 14. The upper end surface of the cylinder sleeve l, that is, the upper surface of the top fi14 is connected to the cylinder block B.
It is designed to match deck surface 3. Therefore, when the Radgas Kent is assembled into the cylinder of the cylinder block B, the gasket and the upper surface of the top wall 14 come into close contact to form a gas seal.

Cooling water is introduced into a space 15 surrounded by the inner wall 11 and outer wall 12 of the cylinder sleeve 1 from a cooling water pump (not shown). The top wall 14 of the cylinder sleeve l is provided with a large number of water holes 16, 16, . . . for circulating cooling water between the cylinder head and the water jacket. That is, the space 15 within the cylinder sleeve 1 is a closed deck type water jacket.

As shown in FIGS. 1 and 3, the adjacent cylinder C9
The cylinder sleeve 1.1 of C has its respective inner wall 11.11
are arranged close to each other so as to be in contact with each other, and their inner walls 11, 11 are joined together at their adjacent portions, so that the joint portion 11a forms a partition wall that partitions the cylinders C9C between them. There is. The walls 12, 12 of each of these cylinder sleeves 1.1 are also connected to each other at adjacent portions, and a communication passage leading to the space 15.15 of each cylinder sleeve 1.1 is provided outside the joint 11a of each inner wall tt, it. 1
5a is formed. Each inner wall 11.11
The connecting portion 11a has communication paths 15a on both sides.

A slit-like hole ttb communicating with 15a is formed. In this way, by connecting the inner walls tt and ti to each other, the distance between the shafts of each cylinder C2C is shortened, and the engine can be made smaller.

To manufacture such a cylinder block B, first,
Cylinder sleeve 1,1. ...The whole thing is cast in one piece.

Since this sleeve I is made of cast iron, its casting is carried out using a sand mold at low pressure. Therefore, the internal space 1
5 and slit-shaped holes 11b, etc., use sand mold cores.I/)
It can be molded by Sleeves 1, 1. thus integrally molded. ... are assembled into a mold for cylinder block B, leaving the sand in the core intact, and molten aluminum alloy is injected at high pressure around the core to die-cast the cylinder block body 2. After that, the core sand of the sleeve l is extracted. To facilitate the removal of this sand, an opening is provided in the sleeve I extending from its side to the side of the cylinder block B. After the core sand has been removed, the opening is sealed with a plug. Finally, the deck surface of the cast cylinder block B and the inner peripheral surfaces of each cylinder sleeve 1, l, . . . are finished.

In this way, the cylinder sleeve 1. By integrating the whole cylinder block B into a mold, the assembly of the cylinder block B into the mold can be performed at once, and the number of manufacturing steps is reduced. Also, when die-casting the cylinder block body 2, by leaving core sand inside the cylinder sleeve 1 to be cast, the rigidity of the sleeve 1 increases, and the sleeve 1 due to the casting pressure increases. deformation can be prevented.

Furthermore, since the cylinder sleeve 1 has a double structure consisting of the inner wall 11 and the outer wall 712, the molten metal pressure during die casting is absorbed by the outer wall 12, and the inner wall 11 is less likely to deform. . Therefore, the residual stress on the inner wall 11 of the sleeve l is reduced.

In an engine equipped with such a cylinder block B,
During operation, cooling water sent from the cooling water pump is introduced into the space 15 of the cylinder sleeve 1 to cool the cylinder C. At this time, the space 15. That is, between the water jacket and the cylinder C, there is an inner wall 1 of the sleeve l.
1 is present, the heat transfer between them is kept good, and therefore the cooling performance is extremely good. In order to further improve this cooling performance, as shown in FIG. 2, a large number of fins 11f are provided on the outer surface of the inner wall 11, that is, on the side facing the space 15, so that the contact area with the cooling water is increased. Such fins 11f, which are desirable, also serve to increase the rigidity of the sleeve l.

The cooling water introduced into the space 15 of the cylinder sleeve I is further guided to the slit hole 11b of the connecting portion lla of the inner wall 11.11(7) through the communication path 15a. Thereby, each sleeve l.

The connecting portion 11a of the inner wall 11.11 of the cylinder C9C, that is, the partition wall between each cylinder C9C, is sufficiently cooled. Therefore, even if the cylinders C9C are arranged close to each other, the partition wall between them is prevented from becoming particularly high temperature, and the cylinder C9C is thereby prevented from becoming particularly high temperature.
deformation is reduced.

Further, this space 15 is located at the lower end 1 of the cylinder sleeve 1.
It is provided up to 3.

Therefore, the volume of the space 15 is large and the amount of cooling water circulated is also large, so that the cylinder C is sufficiently cooled, and the lower part of the cylinder C is also cooled, so that uniform cooling is promoted, and the sleeve Deformation of the entire l is reduced.

On the other hand, since the inner wall 11 and outer wall 12 of the cylinder sleeve 1 forming the space 15 are connected by the top wall 14 at their upper ends, the rigidity of the upper end of the sleeve 1 is high. Therefore, not only is the outer wall 12 of the sleeve l not deformed or crushed during die-casting, but also during engine operation.
That part is less likely to be deformed by heat. Since the upper surface of the top wall 14 forms the deck surface 3 on which the radial gasket is assembled to the cylinder, the gasket comes into contact with the cylinder sleeve l, which is less deformed, over a large area. Therefore, the sealing performance between them is ensured, and the durability of the gasket is increased.

In this way, the residual stress in the inner wall 11 of the cylinder sleeve 1 is reduced, its cooling performance is improved, and its rigidity is further increased, so that thermal deformation of the inner periphery of the inner wall 1 is almost eliminated. Furthermore, by making the inner wall 11 thicker at the top and bottom and thinner at the center, thermal strain can be further reduced.

Further, since the cylinder sleeve 1 has a double structure with an inner wall 11 and an outer wall 12, and is made of cast iron with good sound insulation, the transmitted sound to the outside is reduced, making it possible to create an engine with less noise. can.

In the above embodiment, the connecting portion 11a of the inner wall 11.11 of the adjacent cylinder sleeve 1.1 is provided with a slit-like hole 11b, but this is provided with a large number of slit-like holes 11b as shown in FIG. Small holes lie, lie, . . . can also be used. By doing this, the joint portion 11a
The rigidity of the material can be increased, and its deformation can be further suppressed.

Furthermore, in the above explanation, the cylinder sleeve is made of cast iron and the cylinder block base material is made of aluminum alloy, but the cylinder sleeve can also be made of highly wear-resistant aluminum alloy, ceramic, etc. Various wear-resistant materials can be used, and other light alloys such as magnesium alloys can be used for the cylinder block base material. Moreover, since the cylinder block body is disposed outside the water jacket in this way, a temperature rise in the cylinder block body can be suppressed. Therefore, it is considered possible to further promote weight reduction of the engine by using a material with extremely low specific gravity, such as synthetic resin, as the material of the cylinder block body, that is, as the base material.

As is clear from the above description, according to the present invention, the cylinder sleeve has a double structure including an inner wall and an outer wall, and the space between the inner wall and the outer wall is used as a water jacket. Thus, even when manufactured under high pressure, a cylinder block with little deformation of the cylinder inner periphery and high cooling performance can be obtained.

[Brief Description of the Drawings] Fig. 1 is a partially cutaway plan view showing an embodiment of a cylinder block according to the present invention, Fig. 2 is a cross-sectional view taken along line nn in Fig. 1, and Fig. 3 is a partially cutaway plan view showing an embodiment of a cylinder block according to the present invention. teeth,
1 is a cross-sectional view taken along the line ■--■, and FIG. 4 is a cross-sectional view similar to FIG. 3, showing another embodiment. l...Cylinder sleeve 2...Cylinder block body 3...Deck surface 11...Inner wall 11a...Joining portion 12...Outer wall 14...Top wall 15...Space B... Cylinder block C...Cylinder applicant
Honda Motor Co., Ltd. Representative Patent Attorney Yu Morishita Hajime

Claims (3)

[Claims] (1) In an engine cylinder block formed by surrounding the outer periphery of a cylinder sleeve 1 made of wear-resistant material with a base material, the cylinder sleeve 1 has an inner wall 11 and an outer wall 12 integrally connected thereto. and these inner walls 11 and outer walls 1
A cylinder block for a water-cooled engine, characterized in that a water jacket is formed by a space 15 between the cylinder block and the cylinder block. (2) The cylinder block according to claim 1, wherein the inner wall 11 and the outer wall 12 of the cylinder sleeve 1 are connected at a deck surface 3 on which a cylinder rad gasket is assembled. (3) It has a number of cylinders C, C, ..., and the cylinder sleeves 1.1 of the adjacent cylinders C, C are integrated so that their inner walls 11.11 are connected to each other. A cylinder block according to claim 1 or 2, characterized in that: