JPS58211550A - Cylinder block - Google Patents

Abstract

PURPOSE:To improve the strength of coupling and the performance of radiation by protrusively forming a large number of tapered projections to the outer circumference of a cylinder liner consisting of an iron group casting in the cylinder block manufactured by casting the outer circumference of the cylinder liner with an aluminum alloy, etc. in an internal chill method. CONSTITUTION:The cylinder block 1 consists of the cylinder liner 2 in cast iron, etc. and a jacket body 4 in the Al alloy, etc. casting the outer circumference of the liner 2. With the cylinder liner 2, a large number of the tapered projections 3... are formed to the outer circumference, and each projection 3 is formed so as to be bent in the circumferential direction or the axial direction or be inclined in the tangential direction or the axial direction. The jacket body 4 is cast through a pressure casting method or a gravity casting method, and each projection 3 intrudes into the Al alloy, etc. and is buried into them at that time. Cooling fins 5... are formed protrusively to the outer circumference of the jacket body 4. Accordingly, mechanical couling-strength between the liner 2 and the jacket body 4 and the performance of radiation are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cylinder block made of a light alloy such as an aluminum alloy (hereinafter referred to as aluminum alloy).

BACKGROUND OF THE INVENTION A cylinder plotter made of metal was proposed and put into practical use as an internal combustion engine for a vehicle, with the aim of making it lighter and improving its cooling performance. Such a cylinder block is made by preparing a cylinder liner made of iron-based casting, and surrounding it with a tAA alloy, etc., and transmitting the heat of the piston sliding chamber and combustion chamber, which are made up of the liner, to the outer shell, thereby cooling the cylinder liner. Cooling is achieved through fins and water jackets.

In the above cylinder block, the cylinder liner and the outer cylinder block are made of different metals, so even if the cylinder block is cast, it is difficult to achieve the best fit between the joint surfaces of both sides, which causes peeling. When this occurs, a minute gap is created between the liner and the block, resulting in poor heat dissipation and cooling performance, and the cooling performance of the liner is reduced, making the liner more likely to deform and distort, leading to blow-through and oil leakage. , ■It can also cause irritation.

Therefore, attempts were made to improve the compatibility between the liner and the surrounding M-alloy, and to improve the mechanical strength of the two. Therefore, for example, in JP-A-52-147519, an annular protrusion is provided around the cylinder liner. The groove is set in the shape of a 10 gear 1,A
In this case, the liner is cast with a cylinder block, which is the outer covering of the liner, in the axial and circumferential directions (although the bonding strength is improved by a certain degree, the adhesion at the joint surface is poor). It is difficult to expect the best, and it is difficult to expect the occurrence of gaps at the joint surface and improvement of the heat dissipation effect.For example, JP-A-52-147
In No. 519, a chevron-shaped ring-shaped protrusion is provided on the inner periphery of the cylinder 2, but this is similar to the above, and there is room for improvement.

In addition to the above, methods have also been adopted in which M alloy, etc., is cast around the outer periphery of the cylinder liner while applying high pressure.According to such a casting method under high pressure, it is possible to increase the bonding force between the liner and the cylinder block. However, since the casting pressure is high, residual pressure is generated inside the liner that has been cast into the cylinder block.

The present invention has been made in view of the above, and its purpose is to provide excellent mechanical bonding strength between the outer periphery of the cylinder liner and the outer shell such as shell metal, and to achieve metallurgical and welding bonding. The bonding between the two surfaces is strong and reliable, and it is possible to bond them together as one body.The heat transfer performance from the liner to the outer jacket is extremely good, and the heat dissipation is extremely good. To provide a cylinder block cast with an excellent cast iron liner KL'-E alloy.

In order to achieve the above object, the present invention includes a cast cylinder liner with a large number of inclined or curved protrusions that are integrally formed on the outer periphery of the cast cylinder liner and have a substantial length.
It is characterized by being cast in A6 alloy or the like.

Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 is a cross-sectional plan view of the cylinder block, and Figure 2 is an enlarged view of the same essential parts.The cylinder block 1 consists of a cast iron cylinder liner 2 that forms the inner diameter of the cylinder, and an M alloy etc. that is cast around the outer periphery of the liner. It consists of an outer covering 4. The outer periphery of the cylinder liner 2 is integrally provided with a large number of protrusions 6...all of which protrude independently. The tip portion 6b is tapered so that at least one of the thickness and width is small, and is set to have a substantial length. The protrusions 6 protrude from the outer circumferential surface of the cylinder liner 2.
The protrusions 3 may be curved in the t 111 + horn direction and inclined in the tangential force direction or in the direction of the tangential force, and the protrusions 3 may be provided spaced apart from each other and regularly oriented in the same direction, or They may be arranged in irregular directions and spaced apart so that their directions are opposite to each other. In the embodiment, the protrusions 3 are provided on the outer circumferential surface of the cylinder liner so as to curve in the same direction in the circumferential direction.

It is preferable that the protrusions 3 have a protrusion length of 10% or more of the wall thickness of the cylinder liner 2. For example, the liner wall thickness is 3 mm, the protrusion length is 0.5 mm, and the protrusion length is 0.5 mm. The diameter of the protrusions was 1.01111 mm at the base, and 0.2 mm at the tip, and the spacing between the protrusions was at least equal to the dimension of the base, so as not to impair mud lifting performance.

The entire external appearance of the inner cylinder 2 is shown in FIG. 3 as a perspective view, FIG. 4 as an end view, and FIG. 5 as a cutaway sectional view of the main parts.

The outline of the manufacturing process of the cylinder liner 2 having such projections 3 will be explained with reference to FIGS. 6 to 11. FIG. Seven chill a is made of a flexible elastic material such as rubber or synthetic resin, and the surroundings of the model a to be bent are hardened with sand that hardens at room temperature, and CO2 gas etc. are blown into it. For example, a mold d as shown in FIG. 7 is molded using a CO2 molding method, a cold box molding method, or the like. The mold d has many tapered and curved recesses e having the same shape as the protrusions C open on the surface, and after hardening, the model b' is removed from the mold d as shown in Figure 8. The protrusion C... is the recess e...
It is bent and pulled out following the shape of the recess, without damaging the inner wall of the recess.

The cores f are placed on the surface of the mold thus obtained so as to be spaced apart from each other, and a molding space 9 communicating with the recesses e is formed between the cores f, and molten metal is poured into the molding space by vacuum casting, centrifugal casting, etc. The molten metal is poured to sufficiently fill the molten metal up to the tip of the fourth part e, and after solidification, the mold and core are removed to obtain a cylinder liner having protrusions on the outer peripheral surface.

Specifically, as shown in Figs. 10 and 11, the model ai described above is set in a cylindrical shape, and a casting flask h is placed around the outer periphery of the model ai.
During this time, sand is filled and hardened, and then the mold is bent inward and removed to obtain a mold d. A small-diameter core ft is inserted into the mold to cast the liner. In the figure, e indicates a recess for molding the protrusion, and q indicates a molding space.

By the way, the protrusion of the cylinder liner is not limited to the above, and the protrusion is the first one.
As shown in FIG. 2, a group of protrusions 103a are provided so as to incline in one direction, and a group of protrusions 103b are provided as shown in FIG.
The tip 203at is curved into a hook shape, the protrusion 603 is inclined and curved in the same direction as shown in Fig. 14, the protrusion 406 is made into a half-moon blade shape as shown in Fig. 15, etc. Any shape can be selected.

The entire outer circumference of the cylinder liner 2 formed in the above manner is poured with molten metal such as M alloy, and the liner 2 is cast into the outer cover 4. Casting of the bendable outer cover 4 is performed by pressure casting or gravity casting, and the protrusions 3 integrally protruding from the outer periphery of the liner 2 form the outer cover 4 that solidifies in close contact with the outer periphery of the liner 2. It penetrates into the interior of the main body, such as metal parts, and becomes embedded and joined.

The state in which it is cast into such an outer shell is shown in FIGS. 1 and 2, and cooling fins 5 are provided on the outer periphery of the outer shell 4, and the cylinder block of an air-cooled engine is shown in the example. .

Next, to explain the functions and effects in detail, the outer cover 4 and the liner 2
A protrusion 6 integrally provided on the outer periphery of the liner 2 on the joint surface with the liner 2...
The protrusions 3 do not simply protrude in the radial direction, but are curved or inclined, and are curved or inclined and bite into the central metal casting, intertwining with each other.

In addition, the protrusions are long and thin and have extremely large numbers of stages, and when they penetrate and bite into the other party, the bonding strength is extremely high compared to conventional gear-like concave protrusions or small particle-like protrusions, and therefore the liner 2 and the outer sheath The mechanical connection with the M alloy casting is strong and reliable.

In particular, the protrusions on the outer periphery of the liner are tapered, small in diameter, or thin. Therefore, when pouring the M alloy and casting the cylinder block, its heat capacity is extremely small, so unlike the liner body, the temperature of the molten metal rises quickly, and as a result, the protrusion and the M alloy form a kind of metallurgical bond, a kind of welding bond. This is expected to result in an even stronger bond between the protrusion and the shell metal casting, and a bond between the liner and the outer sheathing alloy that is difficult to peel off.

Incidentally, in the above, the liner may be heated independently of the molten metal using a high-frequency heating means or the like when casting the outer covering M alloy to promote the above-mentioned bonding between the protrusions and the molten metal.

As described above, the bond between the liner and the M alloy that is cast around it can be made dramatically stronger than in the past, and the compatibility of the bonding surfaces between the two can be greatly improved.

Next, the contact area of the cylinder liner 2 with the M alloy jacket 4 is increased by the projections 6, which increases the heat radiation and heat transfer area to the cylinder block with good thermal conductivity, and the liner 2. Heat dissipation and cooling effects are improved compared to conventional products. In particular, in the present invention, the bond between the protrusion and the jacket M alloy casting is strong and does not cause peeling, so it is possible to prevent peeling between the two and the creation of a gap due to this, and the outer periphery of the liner. , heat conduction to the outer cover through the protrusions is ensured, heat radiation and cooling are performed reliably, and high cooling performance can be stably guaranteed over a long period of time.

In this way, a cylinder block with excellent cooling performance can be provided.

This is a longitudinal cross-sectional view of the main part, with the length of the protrusion of the liner 102 being changed in the upper and lower directions in the axial direction. The upper half of the liner 102 is exposed to combustion gas during the combustion stroke, so the upper half protrusions 103a and
The projection 106b on the lower half below the contact area with the piston at the bottom dead center of the piston... is made longer and the heat dissipation contact area is increased.
- is shortened because it does not require as much heat dissipation as the upper half.

FIG. 17 is a cross-sectional view of a cylinder block for a water-cooled two-cylinder engine, showing liners 202A arranged in parallel.

The opposing part of 202B is the bridge part 2 of the inner jacket 204A.
04B, the outer cover 204A excluding this portion is surrounded by a water passage 206, and the outer cover 204C faces the outside of the water passage 206.

The above-mentioned protrusion 206 has no water passage in the opposing part of the liners 202A and 202B as the bridge part 204B.Therefore, in order to increase the heat dissipation area, the protrusion 206a... is set long, and the other parts have water passages 206 on the outside. The protrusion 206
By shortening b..., this makes liner 204A,
The temperature distribution and cooling function of each part of 204B were averaged.

Although the embodiments have been described in detail above, the present invention can be implemented in various types of internal combustion engines.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a cross-sectional view of a cylinder block according to the present invention, FIG. 2 is an enlarged view of the same main part, and FIG. 3 is a perspective view of a cylinder liner. 4 is an end view of the same, FIG. 5 is a broken side view of the same essential parts, FIGS. 6 to 9 are explanatory views of mold forming for liner molding, FIGS. 10 and 11 are explanatory views of cylinder liner casting, 12 to 15 are views of a modified example of the protrusion, and FIGS. 16 and 17 are views of a modified example of the cylinder block. In the drawing, 1 is the cylinder block, 2 is the cylinder liner,
6 is a protrusion. Fig. 6 - Expansion 77 yaw Fig. 11 Fig. 12 Narrowing - Fig. 15 Fig. 17 k Fig. 16 93a

Claims (1)

[Claims] In a cylinder block in which the outer periphery of a cylinder liner made of iron-based casting is surrounded by aluminum alloy or the like, a large number of projections having tapered and preferably inclined or curved lengths are integrally provided on the outer periphery of the cylinder liner, and the projections are A cylinder block characterized by being cast and embedded in a cylinder block made of aluminum ram alloy, etc.