JP6979171B2 - Casting and packaging members and their manufacturing methods - Google Patents

Description

The present invention relates to a member for casting and wrapping and a method for manufacturing the same.

With the development of die-casting technology, etc., a previously cast member is set in a mold, and a metal such as molten aluminum is poured between the part and the mold, and the casting package is adhered or adhered to the part. A technique called casting has come to be used. The member cast by this method is called a casting / wrapping member (also referred to as a casting member).

Examples of the casting and wrapping member include a cylinder sleeve (also referred to as a cylinder liner or sleeve) cast into a cylinder block of an internal combustion engine, a boss or drum of a die cast wheel hub, a bearing portion such as a cylinder block or a lower case, and the like. , There are bearing members cast into the bearings inside the mission case. In particular, when used for the above purposes, a heat load or a large external force often acts on the casting and wrapping member, which improves the adhesion between the casting and wrapping member and the metal that wraps the member, and has heat dissipation and heat transfer properties. Furthermore, it is required to improve the rigidity.

In Patent Documents 1 to 3, in a sleeve cast and wrapped by die casting, the sleeve has a single needle-shaped convex portion whose tip is constricted on the outer peripheral surface of the sleeve, and the adhesion or thermal conductivity is changed between the upper part and the lower part of the sleeve. The treated sleeve is described.

Japanese Unexamined Patent Publication No. 2007-016736 Japanese Unexamined Patent Publication No. 2007-016734 Japanese Unexamined Patent Publication No. 2007-016735

Different properties may be required in two different regions of the casting and wrapping member in the sleeve. For example, in a cylinder block for an engine, in the piston sliding region on the deck side, high adhesion and high thermal conductivity between the casting member and the metal to be cast are required, whereas in the piston sliding region. In the area on the crankcase side, relatively low adhesion and low thermal conductivity are required. In order to change the adhesion and thermal conductivity in these two different regions of the casting and packaging member, there is also a method of roughening the surface of the casting and packaging member and forming a film, but these methods are used for manufacturing. There is a problem that the process becomes complicated.

Therefore, in view of the above problems, the present invention provides a casting and packaging member and a method for manufacturing the same, which can easily and significantly change the characteristics such as adhesion and thermal conductivity in two different regions of the casting and packaging member in the sleeve. The purpose is to provide.

In order to achieve the above object, according to one aspect of the present invention, the present invention is a casting and wrapping member having a mesh-like convex portion and a flat surface on the surface to be cast, and the mesh-like convex portion is , A linear portion and an aggregated portion where at least two linear portions meet, the convex portion comprising a vertical wall portion rising from the flat surface, and the flat surface of the convex portion of the linear portion. It is provided with a high convex portion region having a relatively high height from the above and a low convex portion region having a relatively low height from the flat surface of the convex portion of the linear portion.

A plurality of regions may be formed in each of the high convex region and the low convex region. Further, there may be a convex portion having a height intermediate between the high convex portion region and the low convex portion region. The vertical wall portion of the convex portion of the linear portion is not limited to being perpendicular to the flat surface, and may have an inclination. Further, the convex portion may include a top portion in addition to the vertical wall portion, and the convex portion may have a shape in which the width of the top portion is larger than the width of the vertical wall portion.

The casting and wrapping member may have a cylindrical shape, and in this case, it is preferable to include the high convex portion region and the low convex portion region along the axial direction or the circumferential direction of the cylindrical shape.

The casting / wrapping member may be a cylinder sleeve cast into an engine cylinder block. In this case, the deck surface side may be provided with the high convex portion region, and the crankcase side may be provided with the low convex portion region. preferable. Further, in this case, it is also preferable to provide the high convex portion region in the suction / exhaust direction and the low convex portion region in the front-rear direction.

The difference between the height of the convex portion in the high convex portion region and the height of the convex portion in the low convex portion region is preferably 0.1 mm or more, and more preferably 0.2 mm or more. The upper limit of this difference is preferably 1.0 mm or less, more preferably 0.5 mm or less. The difference in the height of the convex portion here means the difference in the height of the average convex portion in the high convex portion region and the average height of the convex portion in the low convex portion region.

The present invention is another aspect of the method for manufacturing a member for casting and wrapping, in which a step of applying a mold coating agent to a surface on which a molten metal of a mold is to be poured and a step of applying the coating agent are dried. The process includes at least a step of forming a coating layer having a cracked shape on the surface and a step of pouring molten metal from the coating layer and casting while rotating the mold, and pouring the molten metal of the mold. The surface to be attempted has at least two different height regions, whereby the coating layer has a relatively thick region and a thin region, and the cracks are said to be said. In the thick region, the width of the crack is relatively large and the depth is deep, and in the thin region, the width of the crack is relatively small and the depth is shallow.

The wide and deep cracks formed in the thick region of the coating layer can be controlled so that the crack depth is shallower than the thickness of the coating layer in the thin region. preferable. In particular, when the mold has a cylindrical shape and the surface on which the molten metal is to be poured is the inner peripheral surface thereof, the mold has a reference inner diameter consisting of a reference inner diameter having a relatively small inner diameter as the thin region. A region and a non-reference inner diameter region having a relatively large inner diameter are provided as the thick region, and a crack having a large width and a deep depth is controlled so that its depth stays within the region of the reference inner diameter. Is preferable. The inner diameter difference between the reference inner diameter region and the non-reference inner diameter region is preferably 0.1 mm or more, more preferably 0.2 mm or more. Further, the upper limit of the inner diameter difference is preferably 1.0 mm or less, more preferably 0.5 mm or less.

According to the present invention, there is a highly convex region on the surface of the casting member to be cast and wrapped, which is a mesh-like convex portion in which the height of the convex portion of the linear portion is relatively high. By providing a low convex portion region in which the height of the convex portion is relatively low, the member cast and cast using this casting and wrapping member is cast with the casting and wrapping member in the portion of the high convex portion region. High adhesion and high thermal conductivity with the wrapping metal can be obtained, while relatively low adhesion and low thermal conductivity can be obtained in the low convex region portion. As described above, by using a single casting / wrapping member, the adhesion and the thermal conductivity can be easily and greatly changed in two different regions of the casting / wrapping member.

In particular, when this casting / wrapping member is used as a cylinder sleeve to be cast into an engine cylinder block, it is cast by providing a high convex region on the deck surface side and a low convex region on the crankcase side. The cylinder block obtained by wrapping casting can obtain high adhesion and high thermal conductivity between cast iron and aluminum in the piston sliding region on the deck surface side, and can suppress bore distortion during actual engine operation. .. On the other hand, since the thermal conductivity is low in the region other than the piston sliding region on the crankcase side, it is possible to suppress heat dissipation from the sleeve to the cylinder barrel (aluminum side) and make the temperature of the entire sleeve uniform. Since it is possible, it is possible to suppress bore distortion as a whole. As a result, fuel efficiency can be improved by reducing mechanical loss and blow-by gas.

In addition, by casting and wrapping the sleeve so that the FR direction of the engine and the low convex region of the sleeve match, it is possible to bring the sleeves closer to each other while ensuring the thickness of the aluminum, and the pitch between the bores can be shortened. Can be made lighter or downsized. Further, by forming the convex portion, the anchor effect eliminates the generation of a partial gap at the contact interface between the sleeve and aluminum, so that the sleeve wall temperature is also stabilized. As a result, the thermal conductivity from the sleeve to the cylinder barrel is improved and made uniform, and the heat dissipation of the engine combustion heat can be improved. Therefore, it is possible to cope with the rise in the temperature inside the cylinder, and it is possible to achieve high compression of the engine.

It is a perspective view which shows typically the cylinder sleeve which is an example of the casting and wrapping member which concerns on this invention. FIG. 3 is an enlarged plan view schematically showing the surface of the cylinder sleeve of FIG. 1. FIG. 3 is a schematic cross-sectional view showing a cylinder sleeve along lines III-III of FIG. A cross-sectional view showing an example of a cylinder block having the cylinder sleeve of FIG. 1 as a component is shown. FIG. 4 is an enlarged cross-sectional view showing the periphery of the cylinder sleeve in FIG. (A) and (B) are cross-sectional views schematically showing an example of a linear convex portion on the surface of a casting and wrapping member according to the present invention when applied to the molds shown in FIGS. 9 to 11, respectively. .. (A) and (B) are cross-sectional views schematically showing an example of a substantially Γ type of a linear convex portion on the surface of the casting and wrapping member according to the present invention when applied to the mold shown in FIG. be. (A), (B), and (C) are schematically examples of a substantially T-shaped linear convex portion on the surface of the casting and wrapping member according to the present invention when applied to the mold shown in FIG. It is sectional drawing which shows. It is sectional drawing which shows typically an example of the mold which can be used in the manufacturing method of the casting and wrapping member which concerns on this invention. It is sectional drawing which shows typically another example of the mold which can be used in the manufacturing method of the casting and wrapping member which concerns on this invention. It is sectional drawing which shows still another example of the mold which can be used in the manufacturing method of the casting and wrapping member which concerns on this invention. It is a schematic flow chart explaining one Embodiment of the manufacturing method of the casting and wrapping member which concerns on this invention. It is a schematic flow chart explaining the formation mechanism of the coating type layer in the manufacturing method of the casting and wrapping member which concerns on this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings, but the scope of the present invention is not limited to this embodiment. It should be noted that the drawings are not necessarily drawn to scale, giving priority to the understanding of the present invention.

First, an embodiment of the casting and wrapping member according to the present invention will be described. The casting and wrapping member of the present embodiment has a mesh-like convex portion on the surface to be cast and wrapped. Examples of the material for the casting and wrapping member include metals having a large specific gravity and self-sliding properties such as cast iron, copper alloys, tin or zinc alloys. Cast iron is generally a ternary alloy containing iron, carbon and silicon, and may contain other elements depending on the application. For example, in addition to Fe, cast iron has a T.I. C (Total Carbon), 1.9 to 2.5% by mass of Si, 0.5 to 1.0% by mass of Mn, 0.01 to 0.5% by mass of P, 0.02 to 0.1% by mass. May contain% S. In some cases, 0.01 to 1.0% by mass of Cu, 0, in order to obtain the optimum hardness and metallographic structure, when the thickness of the rough material of the casting and wrapping member is large or when the amount of molten metal cast is large. It may contain 0.01 to 0.10% by weight Sn, 0.01 to 0.4% by weight Cr, and other unavoidable impurities.

The shape of the main body of the casting and wrapping member is not particularly limited, and can be appropriately selected according to the intended use. For example, a cylindrical shape, a semi-cylindrical shape, a U-shaped cross section or a ⊥-shaped cross section, a curved surface or a substantially flat plate shape can be mentioned. Examples of casting and wrapping members include cylinder sleeves cast into engine cylinder blocks, sliding members in contact with brake shoes cast into aluminum drum brakes in regenerative brakes of electric vehicles, brake shoe back plates, and two-wheeled vehicles. And the boss of the die cast wheel hub for special machinery, and also those cast into some die cast parts such as the crank journal part of the cylinder block and the lower case, and the bearing part of the housing such as the mission case. Hereinafter, the present invention will be described by exemplifying a cylindrical cylinder sleeve, but the present invention is not limited to a cast-wrapping member having a specific shape or a specific product.

FIG. 1 is a perspective view of a cylinder sleeve 11 which is an example of a casting and wrapping member. Examples of the shape of the cylinder sleeve include a cylindrical shape. The cylinder sleeve 11 is a surface on which the outer surface 11s is cast and wrapped. FIG. 2 shows a schematic plan view in which the region represented by d1 in FIG. 1 is enlarged. The cylinder sleeve has a mesh-like convex portion 3 on the surface 11s to be cast and wrapped. The mesh-like convex portion 3 is a portion protruding from a substantially flat surface F constituting the cylinder sleeve, has a continuous linear protrusion structure, and exists over the entire surface to be cast and wrapped. The mesh-like convex portion 3 includes a linear portion 1 and an aggregate portion 2 formed by merging a plurality of the linear portions.

The mesh-like convex portion is continuously formed on the surface of the casting and wrapping member, and "continuously" is not limited to the mode in which all the linear portions are connected, but a part thereof. It also includes a mode in which only the linear portion of is connected.

In FIG. 2, the linear portion 1 refers to a portion where the convex portion can be confirmed in a continuous linear or strip shape when the surface to be cast and wrapped of the casting and wrapping member is viewed in a plan view from the vertical direction of the surface. .. The linear portion may be a straight line or a curved line, and may have a non-uniform width, length, or height, or may have an irregular shape. That is, it may have a linear portion and an aggregate portion in which the heights of the convex portions are randomly different. As a result, when the molten metal is filled between the convex portions and between the bores, there are places where the portions with lower convex portions face each other as compared with the case where the heights of the convex portions are uniform. This makes it easier for the molten metal to pass between the protrusions and the bores, improving the metal filling property. Furthermore, the bore pitch can be set narrower than before, and the engine can be downsized. The length La in the longitudinal direction of the linear portion and the length Lb in the width direction of the top of the linear portion are not particularly limited. The length of the upper surface of the top surface of the linear portion in the width direction can be measured using, for example, a digital microscope. For example, 1 to 50 points are measured, and the average value or the minimum value and the maximum value are used. It may be obtained as a range including the measured value, preferably a range including all the measured values.

In FIG. 2, the set portion 2 is composed of the set portions 2a, 2b, 2c, and 2d. The assembly portion 2a is formed by merging three linear portions 1a, 1b, and 1c. The number of linear portions merging into the gathering portion is not particularly limited, and is at least two, preferably two or more and six or less. The mesh-like convex portion preferably includes at least two gathering portions. When there are two or more aggregated portions in the mesh-like convex portion, the number of linear portions merging in each aggregated portion may be the same or different. The mesh-like convex portion formed on the outer peripheral surface brings about the effect of a reinforcing rib that improves the rigidity of the casting and wrapping member. Moreover, in the aggregated portion, it is preferable that the linear portions merge with each other in random directions from the viewpoint of dispersing the stress generated by the external force when the assembled portion is cast and wrapped. The fact that the linear portions merge in random directions means that, for example, the two linear portions merge into the aggregate portion in different directions rather than in parallel.

FIG. 3 is a schematic cross-sectional view showing an enlarged surface configuration of a casting and wrapping member. This cross section is a cross section of a linear portion in the axial direction with respect to the surface of the cylinder sleeve which is a member for casting and wrapping. The convex portion 3 is partially provided with a high convex portion region 3a having a relatively high height and a low convex portion region 3b having a relatively low height of the convex portion on a surface to be cast. For example, it is preferable to provide the high convex portion region 3a and the low convex portion region 3b in the axial direction or the circumferential direction of the casting and wrapping member. By providing a highly convex region in an appropriate portion according to the application and purpose, for example, in an engine cylinder block, by applying it to the deck surface side, suction / exhaust direction, sliding region of a piston, etc., a casting and wrapping member. It is possible to improve the adhesion and thermal conductivity with the aluminum to be cast and wrapped, and suppress bore distortion. Similarly, by providing a low convex region in an appropriate portion, for example, in an engine cylinder block, by applying it to a region other than the crankcase side, the front-rear direction, the sliding region of the piston, etc., the sleeve to the cylinder barrel Since heat dissipation to (aluminum side) can be suppressed and the temperature of the entire sleeve can be made uniform, bore distortion can be suppressed. As a result, fuel efficiency can be improved by reducing mechanical loss and blow-by gas. In addition, by casting and wrapping the sleeve so that the FR direction of the engine and the low convex region of the sleeve match, it is possible to bring the sleeves closer to each other while ensuring the thickness of the aluminum, and the pitch between the bores can be shortened. Can be made lighter or downsized.

The convex portion 3 rises substantially vertically from the flat surface 6. The height ha of the convex portion of the high convex portion region 3a is preferably 0.5 mm or more and 2.0 mm or less, more preferably 0.5 mm to 1.5 mm, and even more preferably 0.8 to 1.2 mm. If it is less than 0.5 mm, the anchor effect on the aluminum to be cast may be insufficient, and the effect of the reinforcing ribs for improving the rigidity may be reduced. In addition, the contact area with aluminum required to diffuse heat may be insufficient. If it exceeds 2.0 mm, it may be difficult to form by centrifugal casting. By setting the height of the convex portion within the above range, the effective area in contact with the metal to be cast increases, the adhesion and thermal conductivity are improved, the bore strain can be suppressed, and the engine and the like are highly compressed. It can also cope with the rise in in-cylinder temperature that accompanies this. The height hb of the convex portion of the low convex portion region 3b is 0.1 mm to 1.0 mm lower than the height ha of the convex portion, preferably 0.2 to 0.5 mm lower. When the difference between hb and ha is smaller than 0.1 mm, heat is excessively dissipated to the aluminum to be cast and wrapped in the low convex region applied to the crankcase side, etc., and the overall temperature becomes non-uniform and the bore distortion occurs. Is likely to occur. If the difference between hb and ha is larger than 1.0 mm, the anchor effect on the aluminum to be cast may be insufficient, especially in the low convex region region, and the effect of the reinforcing ribs for improving the rigidity may be reduced. There is. By setting the difference in height between the high-convex region 3a and the low-convex region 3b to the above range, the thermal conductivity from the casting member to the metal to be cast is made uniform as a whole. Bore distortion can be suppressed. Furthermore, the pitch between bores can be shortened by wrapping the low-convex regions in the same manner.

The height of the convex portion may be obtained by line analysis of an arbitrary surface of the casting and packaging member using, for example, a measurement function of a digital microscope and the image analysis software WinROOF2013, and an average value. Alternatively, observe the cross section with a digital microscope, and within an arbitrary measurement area, the range including the measured value based on the minimum height and the maximum height of each convex portion from the flat surface 6, preferably all the measured values. May be obtained as a range including.

Here, a cylinder sleeve, which is one of the uses of the casting and wrapping member of the present invention, will be briefly described. As shown in FIG. 4, the cylinder block 10 has a cylinder sleeve as one component, and the cylinder block 10 is cast by casting and wrapping a casting member 11 with aluminum 12. FIG. 5 is an enlarged view of the vicinity of the cylinder sleeve of FIG. As shown in FIGS. 4 and 5, in the cylinder block 10, a high convex region is provided in the sliding region of the piston on the deck 13 side, and a low convex region is provided in a region other than the sliding region of the piston on the crankcase 14 side. Can be prepared.

FIG. 6 is a schematic enlarged view of a cross section of a linear convex portion. The convex portion 3 may include a shape having an inclination with respect to a vertical line with respect to a flat surface. In addition to the linear protrusion structure, the convex portion may have irregularities on its side surface 22 as shown in FIG. 6A. Further, as shown in FIG. 6B, the convex portion may extend at an inclination 21 with respect to the vertical line 20 with respect to the flat surface at a certain angle θ. The shape shown in FIG. 6 can be said to be a shape in which the convex portion 3 has an inclination with respect to a vertical line with respect to a flat surface.

Depending on the manufacturing method of the casting and wrapping member, the cross-sectional shape when the linear convex portion is cut perpendicular to the longitudinal direction may be a substantially T-shaped or substantially Γ-shaped shape in addition to the linear protrusion structure. May be. These cross-sectional shapes are preferable from the viewpoint of improving the adhesion strength and thermal conductivity with the metal to be cast, for example, when they are cast and wrapped. The approximately Γ type is shaped like an inverted L-shape. 7 (A) and 7 (B) are examples of linear portions having a substantially Γ-shaped cross section. In FIG. 7 (A), the top of the convex portion becomes thinner toward the end, and in FIG. 7 (B), the top of the convex portion has a constant thickness up to the end. The substantially T-shape has a shape like a T-shape. 8 (A), (B) and (C) are examples of linear portions having a substantially T-shaped cross section.

As shown in FIG. 2 , an inscribed circle Ic can be drawn on the flat surface F surrounded by the linear portions 1a, 1b, 1d, 1e and the gathering portions 2a, 2b, 2c, and 2d. The diameter of the inscribed circle is preferably 0.5 mm or more and 30 mm or less, more preferably 1.0 to 15 mm, and even more preferably 1.5 mm to 5.0 mm. If it is less than 0.5 mm, the effective area in contact with the aluminum during casting is insufficient, it is difficult to maintain the effective anchoring effect on the aluminum to be cast and wrapped, and the thermal conductivity may be insufficient. If it exceeds 30 mm, the effective area in contact with the aluminum after casting may be insufficient, and the effective network structure that contributes to the dispersion of stress generated by the external force may not be obtained. By setting the diameter of the inscribed circle within the above range, the effective area in contact with aluminum during casting is sufficient, the thermal conductivity is improved when used as a casting member, and the network structure disperses stress. Can be. The diameter of the inscribed circle is determined based on, for example, when the casting member has a cylindrical shape, for example, an image obtained by correcting a photographed image of a convex portion on a curved surface onto a plane using a digital microscope. An inscribed circle may be created on a flat surface, and may be obtained by an average value from, for example, 1 to 50 inscribed circles, or a range including the measured value based on the minimum diameter and the maximum diameter, preferably the inscribed circle. It may be obtained as a range in which all the measured values are included. The present invention is not limited to the embodiment in which all the flat portions are surrounded by the linear portions. In this case, an inscribed circle along some linear portions can be drawn and its diameter can be treated in the same manner as described above.

Further, when the surface to be cast and wrapped of the casting and wrapping member is projected on a plane, the projected area in which the mesh-like convex portion is projected on the plane is preferably 5% or more and 70% or less with respect to the total projected area. , More preferably 10% or more and 60% or less, and even more preferably 16% or more and 43% or less. If it is less than 5%, the effective area in contact with aluminum during casting may be insufficient, and the effect as a reinforcing rib for reducing stress generated by an external force may be reduced. If it exceeds 70%, the weight reduction effect may not be utilized. The projected area of the mesh-like convex portion is the area where the convex portion is projected from above the top of the convex portion. By setting the projected area of the mesh-like convex portion within the above range with respect to the total projected area, the adhesion strength, heat transferability, heat dissipation, and rigidity with the metal to be cast and wrapped are improved. This makes it possible to improve the thermal conductivity and specific elastic modulus of the cast-wrapping member after casting. The projected area may be calculated by, for example, taking a picture using a microscope and performing binarization processing based on the plane-corrected image. For example, the average convex portion projected area from the measurement results of 1 to 50 points. It may be obtained by a rate, or it may be obtained as a range in which the measured value is included based on the minimum and maximum values of the area ratio, preferably a range in which all the measured values are included.

The wall thickness 11b of the casting and wrapping member preferably has a thickness of 2 to 20 mm. For example, in FIG. 3, the wall thickness of the casting and wrapping member is the sum of the thickness h9 from the inner peripheral surface to the flat surface of the outer peripheral surface of the casting and wrapping member and the height ha of the mesh-like convex portion in the high convex portion region. The height ha of the convex portion may be preferably 1 to 70%, more preferably 10 to 50% of the wall thickness of the casting and wrapping member.

As described above, since the cast-wrapping member has a convex portion having a linear portion and an aggregate portion on the surface to be cast-wrapped, the area in contact with the metal to be cast-wrapped is increased as compared with the conventional case, and the heat transferability is improved. The heat dissipation can be improved efficiently. Further, the casting and wrapping member includes a high convex portion region in which the height of the convex portion is relatively high and a low convex portion region in which the height of the convex portion is relatively low in an arbitrary region. The metal to be cast bites into the highly convex region applied to the deck surface side, suction / exhaust direction, piston sliding region, etc., improving the adhesion strength and making it difficult to create a gap with the metal to be cast, and the metal to be cast. Since the thermal conductivity to the metal can be improved and made uniform, the bore distortion can be suppressed, and the temperature inside the cylinder can be increased due to the high compression of the engine. Further, in the low convex region applied to the crankcase side, the front-rear direction, the region other than the piston sliding region, etc., heat dissipation can be suppressed and the overall temperature can be made uniform, so that bore strain can be suppressed. Moreover, by suppressing the bore distortion, mechanical loss and blow-by gas can be reduced and fuel efficiency can be improved. Further, by casting and wrapping the sleeve so that the FR direction of the engine and the low convex portion region of the sleeve are aligned with each other, it is possible to bring the sleeves closer to each other while ensuring the thickness of aluminum, so that the pitch between bores can be shortened.

Further, when the convex portion has, for example, an isotropic net structure, the convex portion has an effect as a reinforcing rib, and can contribute to dispersion and reduction of stress generated by an external force from various directions. For example, if the casting and wrapping member is a cylinder sleeve, the specific elastic modulus in the bore radial direction or the axial direction can be improved, and the deformation of the casting and wrapping member can be prevented. Therefore, it is possible to reduce the thickness and weight of the cylinder sleeve while maintaining the same rigidity.

The casting and wrapping member is cast and wrapped with aluminum (also referred to as aluminum), an aluminum alloy, or other non-ferrous alloy. Here, the casting-wrapping member obtained by casting and wrapping the casting-wrapping member with these metals or alloys has good adhesion between the casting-wrapping member and the metal or alloy such as aluminum to be cast-wrapped as described above. The thermal conductivity as a casting and wrapping member is also good. The thermal conductivity can be measured by a laser flash method.

For example, when the casting and wrapping member is a cylinder sleeve cast into an engine cylinder block, the cylinder sleeve uniformly dissipates heat to the surrounding aluminum cylinder barrel, and at the time of combustion pressure and cylinder head fastening. High rigidity is required because a compressive load is easily applied. By applying the present invention to a cylinder sleeve and wrapping the cylinder sleeve with, for example, aluminum, an engine cylinder block having excellent thermal conductivity and thermal diffusivity can be obtained. Further, even if the compression ratio of the engine is increased, heat can be efficiently dissipated from the cylinder sleeve to the aluminum cylinder barrel, and the increase in combustion temperature due to the increase in compression can be suppressed. Furthermore, since the specific elastic modulus of the cylinder sleeve can be improved, if the weight is the same, it is possible to prevent the bore deformation of the cast and wrapped cylinder sleeve, that is, the change in roundness, during the above-mentioned operation and fastening, and the mechanical of the engine. Loss and blow-by gas can be reduced. If the cylinder sleeves have the same rigidity, the sleeve itself can be made thinner and lighter, and the engine can be made lighter.

Next, an embodiment of the method for manufacturing a casting and wrapping member according to the present invention will be described. The method of the present embodiment is a step of applying a mold coating agent to the surface of the mold to which the molten metal is to be poured, and drying the applied coating agent to form a mold coating layer having a crack shape on the surface. It mainly includes a process and a process of pouring molten metal from the coating layer and casting while rotating the mold. Each of these steps will be described in detail below.

The material and shape of the mold for molding the casting and wrapping member are not particularly limited, and may be selected according to the rough material and the intended use of the target casting and wrapping member. For example, when molding a cylinder sleeve to be cast into an engine cylinder block as a member for casting and wrapping, the mold is preferably a metal mold, and preferably has a cylindrical shape.

As a mold that can be used in the method of the present embodiment, for example, as shown in FIG. 9, the inner peripheral surface 31s of the mold has a relatively small inner diameter with respect to the reference inner diameter region Db having a relatively small inner diameter in the axial direction. It may be provided with a large, non-reference inner diameter region Da. The reference inner diameter region Db and the non-reference inner diameter region Da may be provided alternately, may be provided randomly, or may be stepped at the region boundary 80, and may be a target casting member. It may be changed according to the rough material and application. The reference inner diameter region Db and the non-reference inner diameter region Da correspond to the low convex portion region and the high convex portion region in the casting and packaging member, respectively. The inner diameter of the reference inner diameter region Db is the reference inner diameter D, and the inner diameter difference Dc between the reference inner diameter region Db and the non-reference inner diameter region Da is 0.1 mm to 1.0 mm, preferably 0.2 to 0.5 mm. By setting the inner diameter difference Dc to the above range, by providing convex regions with different heights at appropriate locations, for example, when applied to an engine cylinder block in a cast-wrapping member after molding, a deck. By applying the high convex region to the surface side, suction / exhaust direction, piston sliding region, etc., and applying the low convex region to the crankcase side, front-rear direction, region other than the piston sliding region, etc., the casting and wrapping member The thermal conductivity from the metal to the metal to be cast and wrapped is made uniform as a whole, and bore strain can be suppressed. Furthermore, the pitch between bores can be shortened by wrapping the low-convex regions in the same manner.

As another example of the mold that can be used in the method of the present embodiment, as shown in FIG. 10, the reference inner diameter region Db and the non-reference inner diameter region Da provided on the inner peripheral surface 31s of the mold are not stepped. It may also have a wavy shape in which the inner diameter changes continuously, for example.

As a mold that can be used in the method of the present embodiment, as yet another example, as shown in FIG. 11, the inner peripheral surface 31s of the mold has a reference inner diameter region Db and a non-reference inner diameter region Da in the direction perpendicular to the axis. And may be provided. By forming the shape having grooves in the axial direction in this way, it becomes easy to remove the molded body from the mold, and it becomes easy to manufacture the casting and wrapping member. In addition, when a plurality of molded members for casting and wrapping are brought close to each other (close to each other in parallel), it is possible to bring the members for casting and wrapping close to each other while ensuring the thickness of aluminum by facing the low convex region regions. Therefore, the pitch between bores can be shortened while reliably filling.

The casting / wrapping member having a high convex region and a low convex region partially has a reference inner diameter region having a relatively small inner diameter and a non-reference inner diameter region having a relatively large inner diameter on the inner peripheral surface of the mold. It is preferable to mold by a centrifugal casting method in which the molten metal is poured by centrifugal force while the mold is rotated. In other molding methods, a casting and wrapping member having a convex portion on the outer peripheral surface is manufactured using a mold having a constant inner diameter, and then the height of the convex portion is lowered by cutting to obtain optional adhesion or thermal conductivity. Although it can be changed depending on the area, it is not preferable because the number of processes required for cutting increases and the manufacturing cost increases. The surface of the mold for forming the casting / wrapping member may be, for example, a substantially smooth surface as it is machined.

The manufacturing method of the present embodiment will be described in more detail with reference to the schematic flow chart of FIG. First, as shown in FIG. 12 (a), the mold coating agent 32 is prepared in the container 36. The mold coating agent contains at least a refractory material, a binder and a solvent. In some cases, it may contain aggregate.

As the refractory material, diatomaceous earth powder is preferable from the viewpoint of protecting the surface of the mold, preventing the molten metal from becoming white pig iron, and ensuring sufficient mold releasability. The lower limit of the blending amount of the refractory material is preferably 2% by mass or more, more preferably 8% by mass or more, and the upper limit is preferably 40% by mass or less, more preferably, with respect to the total mass of the coating agent. Is 27% by mass or less, and more preferably 15% by mass or less.

Examples of the binder include bentonite, montmorillonite, kaolinite, sepiolite, attapulsite, and refractory clay. In particular, bentonite that absorbs the solvent and swells is preferable because it can suppress separation when mixed with a solvent together with a refractory material or an aggregate and have a viscosity that allows the mold to be attached to the surface of the mold. The lower limit of the blending amount of the binder is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 8% by mass or more, and the upper limit is set with respect to the total mass of the coating agent. It is preferably 20% by mass or less, more preferably 12% by mass or less, still more preferably 10% by mass or less. If it is less than 2% by mass, separation from the refractory material is likely to occur, and the strength of the coating layer may be insufficient. If it exceeds 20% by mass, the slurry viscosity of the coating agent becomes too high and the coating is applied. May be difficult.

Water may be used as a solvent. The lower limit of the blending amount of the solvent is preferably 60% by mass or more with respect to the total mass of the coating agent, and the upper limit is preferably 85% by mass or less. In addition to the above-mentioned materials, the coating agent may contain an organic solvent having a boiling point higher than that of water, such as butanol, and in this case, it may be miscible with water.

The mold coating agent may also contain an aggregate in addition to the materials described above. As the aggregate, mineral powder or artificial ceramic sand composed of aluminum oxide and silicon dioxide such as Murite and Cera beads, and cast sand such as zircon sand, chromate sand, silica sand, olivin sand and spinel sand may be used. good. In particular, the specific gravity is small to prevent separation from the refractory material and the binder, and it does not absorb the solvent, promotes the shrinkage of the coating layer during drying and solidification, and increases the cracking of the coating layer. Mullite and cera beads are preferred. The lower limit of the blending amount of the aggregate is preferably 1.0% by mass or more, more preferably 1.5% by mass or more, still more preferably 3.0% by mass or more, based on the total mass of the coating agent. The upper limit is not particularly limited, but is preferably 25% by mass or less, and more preferably 10% by mass or less.

A refractory material, a binder, and a solvent may be mixed at least, and an aggregate may be mixed as the case may be used to obtain a slurry-like coating agent.

Next, as shown in FIG. 12B, the mold coating agent 32 is applied to the inner peripheral surface 31s to which the molten metal of the mold 31 is to be poured. In the step of applying the mold coating agent, the mold coating agent 32 is applied to the inner peripheral surface 31s of the mold by using the nozzle 41 while rotating the tubular mold 31 in a constant direction 40. It is preferable that the nozzle 41 is moved in the longitudinal direction 42 of the cylinder at a constant speed while maintaining a constant distance from the inner peripheral surface 31s of the mold, and is uniformly applied to the entire inner peripheral surface of the cylinder. When using a cylindrical mold, for example, it is preferable to rotate the mold in a state where the cylinder is laid on its side and rolled. The centrifugal acceleration of the mold during rotation is preferably set to 4 G or more and 40 G or less.

It is preferable that the inner peripheral surface 31s of the mold when the mold is applied to the mold is heated to a temperature at which the mold does not soar. The heating temperature is preferably 110 to 210 ° C, more preferably 120 to 180 ° C.

Then, as shown in FIG. 12 (c), the applied coating agent is dried to form a coating layer 32s having regions having partially different widths and depths of cracks. In the step of forming the mold coating layer, it is preferable to rotate the mold 31 in a constant direction 40 until the mold coating agent is dried.

The mold can be dried by rotating the mold as it is after coating. The mold may be dried and solidified while it is still heated or by the heat of the further heated mold. The rotation holding time is preferably 0.25 to 3 minutes. Alternatively, after stopping the rotation of the mold, the mold may be heated from the inside or the outside of the mold as needed to shorten the drying and solidifying time.

When it is dried by further heating after coating, it is preferably heated at a temperature equal to or higher than the evaporation temperature of the solvent and not higher than the evaporation temperature by 110 ° C. As a result, a predetermined cracked coating layer can be formed in a state where the solvent does not rise sharply from the inside of the coating agent and the excessive generation of bubbles (water vapor) is suppressed. The lower limit of the heating temperature is preferably a temperature equal to or higher than the evaporation temperature of the solvent, more preferably a temperature 10 ° C. higher than the evaporation temperature of the solvent, and further preferably a temperature 20 ° C. higher than the evaporation temperature of the solvent. The upper limit of the heating temperature is preferably 110 ° C. or higher than the evaporation temperature of the solvent, and more preferably 80 ° C. or lower than the evaporation temperature of the solvent.

The thickness of the coating layer after drying is not particularly limited, but preferably has an average thickness of 0.1 mm to 5.0 mm, more preferably 0.5 mm to 2.0 mm. preferable.

Here, the mechanism for forming the coating layer will be described with reference to FIG. As shown in FIG. 13A, for example, even if the inner peripheral surface 31s of the mold 31 has a step or the like and the height is different, the surface of the mold coating agent 32 is formed substantially smooth. Then, a part of the volatile component 33 evaporates from the mold coating agent 32 on the inner peripheral surface 31s of the heated mold 31. FIG. 13B shows the initial state of the coating layer 32s at the time of drying and solidification. At this stage, a large amount of the volatile component 33 evaporates from the coating layer 32s, shrinkage 34 begins to occur at random intervals on the surface of the coating layer 32s, and cracks 35i occur. Here, since the amount of the volatile component 33 also differs depending on the difference in the thickness of the coating layer 32s, the amount of shrinkage 34 also differs. The larger the thickness of the coating layer 32s, the larger the amount of shrinkage, so that the width of the crack 35i becomes larger and deeper. Therefore, as the drying progresses, the coating layer in the reference inner diameter region Db has a relatively small crack width and a shallow depth, and the coating layer in the non-reference inner diameter region Da has a relatively large crack width and depth. Becomes deeper.

FIG. 13 (c) shows the terminal state at the time of drying and solidifying. The shrinkage 34 of the coating layer 32s further progresses, cracks 35 m expanding toward the surface of the mold 31 are generated from the surface of the coating layer 32s, and the cross section of the void in the thickness direction of the coating layer becomes a wedge shape. In this state, the difference in the width and the depth of the cracks becomes remarkable due to the difference in the thickness of the coating layer 32s, and the low crack region Eb consisting of the cracks 35 mb having a relatively small width and a shallow depth. A high crack region Ea is formed, which is composed of cracks of 35 ma having a relatively wide crack width and a deep crack depth. It completely dries and solidifies in such a cracked state.

In the final state at the time of this dry solidification, the mold as shown in FIG. 9 having the reference inner diameter region and the non-reference inner diameter region in the axial direction, and the reference inner diameter region and the non-reference inner diameter region are not stepped. For example, when a mold as shown in FIG. 10 having a wavy shape in which the inner diameter changes continuously is used, the cracks 35ma and 35mb in either region should be adjusted so as not to reach the inner peripheral surface 31s of the mold. Is preferable. In particular, it is preferable to control the depth of the crack so that the crack 35ma having a large width and a deep depth does not become deeper than the reference inner diameter D of the mold 31. As a result, when the casting and wrapping member is molded and then pulled out from the mold 31, the highly convex region formed in the crack 35ma of the high crack region Ea is not damaged by the inner peripheral surface 31s of the mold 31 and is smooth. It can be pulled out more easily, and a casting and wrapping member having a desired structure can be formed more easily.

On the other hand, in the final state at the time of drying and solidification, when a mold as shown in FIG. 11 having a reference inner diameter region and a non-reference inner diameter region in the direction perpendicular to the axis is used, a casting and packaging member is formed. Then, since it is pulled out from the mold 31 in the axial direction, even if the cracks 35ma and 35mb reach the inner peripheral surface 31s of the mold and the cracks 35ma become deeper than the reference inner diameter D of the mold 31, the cracks 35ma , The convex portions of the high convex portion region and the low convex portion region formed at 35 mb can be smoothly pulled out without being damaged, and a casting and wrapping member having a desired structure can be more easily formed.

FIG. 13 (d) shows a state in which drying and solidification have further progressed as compared with FIG. 13 (c). Deeper cracks 35f occur in the coating layer 32s. In the low crack region Eb, cracks 35fb that penetrate the coating layer and reach the inner peripheral surface 31s of the mold are generated, and in the high crack region Ea, cracks 35fa deeper than the reference inner diameter D are generated.

When this dry solidification is in progress, the mold as shown in FIG. 9 having the reference inner diameter region and the non-reference inner diameter region in the axial direction, and the reference inner diameter region and the non-reference inner diameter region are not stepped. For example, when a mold as shown in FIG. 10 having a wavy shape in which the inner diameter changes continuously is used, the crack 35fb may reach the inner peripheral surface 31s of the mold, or the crack 35fa deeper than the reference inner diameter D may occur. Then, when the casting and wrapping member is formed and then pulled out from the mold 31, it becomes difficult to pull out the highly convex portion region formed in the crack 35fa. Therefore, when a mold having a reference inner diameter region and a non-reference inner diameter region in the axial direction is used, the low convex portion region and the high convex portion region may have a convex portion having an inclination as shown in FIG. It is preferable to control the height of the convex portion so as not to have the convex portion having the constriction as shown in FIGS. 7 and 8.

On the other hand, when a mold as shown in FIG. 11 having a reference inner diameter region and a non-reference inner diameter region in the direction perpendicular to the axis is used in the state where this drying solidification has progressed, the reference is based on the high crack region Ea. Even if the crack 35fa deeper than the inner diameter D is generated, the crack 35fb in the low crack region Eb may reach the inner peripheral surface 31s of the mold. This is because after the casting and wrapping member is molded, it is pulled out from the mold 31 in the axial direction, so that it can be pulled out smoothly. The cracked 35fb that has reached the inner peripheral surface 31s in this way further expands along the mold surface due to the shrinkage of the coating layer. The convex region formed in the crack thus obtained includes a convex portion having a constriction as shown in FIGS. 7 and 8. That is, when a mold having a reference inner diameter region and a non-reference inner diameter region in the direction perpendicular to the axis is used, as shown in FIGS. 7 and 8, in addition to the convex portion having an inclination as shown in FIG. It may also have a convex portion with a tight constriction.

Returning to the description of the method for manufacturing the casting and wrapping member, as shown in FIG. 12 (d), the cast iron molten metal 43 is poured into the mold 31 from above the mold layer 32s, and the mold 31 is rotated in a certain direction 40. Centrifugal casting while. In this casting step, as in FIG. 12B, the molten metal can be poured into the inside of the cylinder by using a molten metal supply means such as a nozzle while rotating the mold. When rotating the mold, the centrifugal acceleration of the mold is preferably set to 100 G or more and 120 G or less. By rotating the mold, the molten metal flows into the cracks of the coating layer by centrifugal force, and a desired linear protrusion structure can be formed on the surface of the casting and wrapping member. The temperature of the molten metal is not particularly limited as long as it is a temperature at which the cast iron, metal, alloy or the like to be used melts, but it is preferably 1380 to 1450 ° C. for cast iron. Further, the temperature of the mold when the molten metal is put into the mold is preferably 100 to 300 ° C.

Then, as shown in FIG. 12 (e), the molten cast iron is solidified. In this solidification step, the molten cast iron 43 is cooled from the outside of the mold 31 and solidified to obtain a molded body 44 of a member type for casting and wrapping. After the molten metal is poured into a mold and cast, it may be held for 0.25 to 1 minute and naturally cooled to solidify. For example, the temperature of the molded product is 100 ° C. from the eutectic solidification end temperature to the eutectic solidification end temperature. The molten metal may be coagulated by natural cooling to a low temperature. After solidifying the molten metal, it is preferable to stop the rotation of the mold. In order to prevent ferrite from precipitating in the metal structure constituting the molded body 44, depending on the mass or wall thickness of the casting and wrapping member, the end temperature of the eutectoid transformation (Ar1 transformation), for example, at a temperature up to about 730 ° C. , The outside of the mold may be, for example, water-cooled while rotating the mold. By solidifying and cooling the molten metal in this way, a member-type molded body for casting and wrapping can be obtained.

Next, in FIG. 12 (f), the cast-wrapping member type molded body 44 is taken out from the mold 31. The method for taking out the molded product from the mold is not particularly limited, and the method is selected according to the shape of the mold. For example, in the case of a tubular mold, a chuck having a claw that opens outward is attached to the inner diameter end of the molded body 44, and the other end side of the chuck is pulled out in the arrow direction 45 in the drawing using a hydraulic cylinder or the like. And can be taken out from the mold 31.

Then, as shown in FIG. 12 (g), the coating layer 32s is removed from the molded body 44 taken out from the mold 31. A mold layer may be attached to the surface of the molded product taken out from the mold. The method for removing the coating layer from the molded body is not particularly limited, and examples thereof include shot blasting, water jet, and dry ice cleaning. For example, the molded body 44 can be moved in the direction of the arrow 46, the blast 47 can be projected onto the mold layer 32s on the surface of the molded body 44, and the mold layer 32s can be removed from the molded body 44. In the case of shot blasting, ceramic powder having a particle size of # 240 to # 8000 and an average particle size of 0.5 to 60 μm may be used as the projection medium, and the projection pressure may be 0.1 to 0.4 MPa. preferable. In the case of a water jet, the projection pressure is preferably 0.1 to 0.4 MPa.

FIG. 12H shows the casting and wrapping member 48 after the coating layer is removed from the molded body. By removing the coating layer from the molded body, a casting and wrapping member 48 having a mesh-like convex portion on the surface 48s thereof can be obtained.

According to the present invention, it is a mesh-like convex portion on the surface to be cast and wrapped of a single casting-wrapping member, which is a mesh-like convex portion that cannot be achieved by a conventional manufacturing method, and the height of the convex portion of the linear portion. Can form a high-convex region and a low-convex region with different values. Further, the casting and wrapping member of the present invention is a member other than sliding parts having high rigidity and excellent heat transfer, heat dissipation and heat conductivity, for example, an aluminum brake drum, a wheel hub made of aluminum die cast for a two-wheeled vehicle, and a power. It can also be applied to cast-wrapping members in parts where rotational torque acts, such as train-type bearing journals.

The above-mentioned manufacturing method is preferable in order to form a continuous linear protrusion structure partially provided with a high-convex portion region and a low-convex portion region on the cast-wrapped surface of the casting-wrapping member. A part of the cast-wrapped surface of the cast-wrapping member may be ground or cut.

The obtained casting and wrapping member may be cast and wrapped by, for example, a die casting method. The injection conditions are not particularly limited, but for example, using ADC12, ADC10, and ADC3, pour hot water at 620 to 670 ° C., injection pressure is 50 to 100 MPa, and injection speed is 1.5 to 4.0 m / sec. You may go. In this way, the cast-wrapping member can be obtained.

(Manufacturing of casting and wrapping members)
<Test Example 1>
The coating agent was prepared by mixing at a mixing ratio of 15% by mass of diatomaceous earth, 10% by mass of bentonite, and 75% by mass of water, and stirring with a power mixer device (manufactured by Ryobi Co., Ltd.).

As a mold for the casting and wrapping member, a cylindrical mold having a reference inner diameter of about 79 mm in the reference inner diameter region and an inner diameter of about 80 mm in the non-reference inner diameter region, which have different inner diameters in the axial direction, is used as a mold for the cylinder. The mold temperature of the inner peripheral surface was set to 160 ° C. This temperature can be measured by a contact thermometer or a radiation thermometer. The mold is formed by applying a coating agent to the inner peripheral surface of the mold using a nozzle while laying the tubular part (longitudinal direction of the cylinder) sideways and rotating it at a centrifugal acceleration of 4 to 10 G. did. After coating, the rotation of the mold was held for about 1 minute to form a coating layer on the inner peripheral surface of the mold. The obtained coating layer had a shape having a region having a partially different width and depth of cracks on the surface thereof, and the average thickness of the layer was about 1 mm. The thickness of the layer was measured by connecting a measuring probe (Fe-2.5LwA) to an electromagnetic film thickness meter (manufactured by Sanko Electronics Laboratory Co., Ltd., model number SWT-8000II) and measuring the surface of the coating layer at 10 points. The average was calculated from those measurements.

Next, the molten metal was poured into a mold having a coating layer formed on the inner peripheral surface, and a member for casting and wrapping was cast. Cast iron melted at 1420 ° C. was used as the molten metal. When the molten metal was poured into the mold, the temperature of the inner peripheral surface of the mold was set to 160 ° C., and the molten metal was rotated at a centrifugal acceleration of 120 G. After pouring the molten metal into the mold, hold it for 0.5 minutes while rotating the mold, and then cool the outer peripheral surface of the mold with cold water to a temperature of 730 ° C or lower while rotating the mold to cool the molten metal. It was solidified and cooled to obtain a molded body of a casting and wrapping member.

After the molten metal is solidified and cooled, the rotation of the mold is stopped, a claw chuck that opens to the outside is attached to the inner diameter end of the molded body, and the other end of the chuck is connected to the hydraulic cylinder and moved in the opposite direction to the mold. The molded product was withdrawn from the mold. A blast was projected onto the outer peripheral surface of the drawn molded product to remove the coating layer from the molded product. The projected blast was a ceramic powder having an average particle size of 23 μm, and the projection pressure was 0.3 MPa. In this way, the coating layer was removed to obtain a long cylindrical rough material for the casting and packaging member having an inner diameter of 64 mm and a wall thickness of 7.5 mm for the casting and packaging member. Further, the rough material of this casting and wrapping member is cut to a required length, and the inner peripheral surface is machined by lathe processing based on the outer diameter to cast a length of 124 mm and a wall thickness of 4.5 mm. A wrapping member was obtained. The wall thickness of the casting and wrapping member is the sum of the thickness from the inner peripheral surface to the flat surface of the outer peripheral surface of the casting and wrapping member and the height of the mesh-like convex portion in the high convex portion region. The thickness of the surface was measured at 5 points, and the average value thereof was calculated. Table 1 shows the observed convex region, the compounding ratio of the coating agent for obtaining the casting and wrapping member, the mold temperature, the wall thickness of the casting and wrapping member, and the high convex region and the low convex region, respectively. Shows the average convex height.

<Test Examples 2-8>
Test Example 1 except that the compounding ratio of the coating agent, the mold temperature, the wall thickness of the casting and wrapping member, and the average convex heights of the high convex region and the low convex region are shown in Table 1. In the same manner as above, a member for casting and wrapping was obtained.

(Making a casting member)
Each of the casting and wrapping members of Test Examples 1 to 8 was die-cast to produce a substantially cylindrical casting and wrapping member whose outer peripheral surface was cast and wrapped with aluminum. Aluminum was cast at an injection pressure of 65 MPa and an injection speed of 2.0 m / sec by pouring hot water at 650 ° C. using ADC12. The obtained cast-wrapping member is lathed with aluminum on the outer peripheral surface having an outer diameter of 81 mm based on the inner peripheral surface thereof, and then the inner peripheral surface of the cast-wrapping member has an inner diameter of 73 mm based on the outer peripheral surface. It was turned into a lathe so that the thickness of the cast and wrapped member was 4 mm.

[Evaluation of thermal conductivity of cast and wrapped members]
A circular plate having a diameter suitable for the test apparatus was carved from the cast and wrapped members of Test Examples 1 to 8 to obtain a test piece. The test piece had the same wall thickness centered on the interface between the casting member and the aluminum that wraps it. As a thermal conductivity test, a laser flash method (LF method) was used on the cast iron surface of the test piece at room temperature (25 ° C.) using a thermal constant measuring device (TC-7000, manufactured by ULVAC Riko Co., Ltd.). Irradiation was performed, the specific heat and the thermal diffusivity were measured, and the thermal conductivity was calculated from the following formula (1).
λ = Cp × α × ρ (1)
In the formula, λ is the thermal conductivity, Cp is the specific heat, α is the thermal diffusivity, and ρ is the density at room temperature. The density at room temperature was calculated using the dimensions and weight of the test piece measured at room temperature (25 ° C.) and in the atmosphere. Table 2 shows the thermal conductivity when filling the molten aluminum.

[Evaluation of adhesion strength of cast and wrapped members]
Eight quadrangular test pieces having a contact area of ^{300 to 500 mm 2} were carved from the cast and wrapped members of Test Examples 1 to 8. A tension jig is fixed to the aluminum side surface and the cast iron side surface of the test piece with a thermosetting epoxy adhesive, and vertical peeling is performed using a precision universal testing machine (AG-100kN Xplus, manufactured by Shimadzu Corporation). A test was conducted. The value obtained by dividing the maximum load when the cast-wrapping member and the aluminum were peeled off by the contact area of the test piece before the test was defined as the contact strength. Table 2 shows the adhesion strength with aluminum when filled with molten aluminum.

It was confirmed that in the convex portion of the high convex portion region, the adhesiveness and the thermal conductivity were improved due to the relatively high convex portion. It was confirmed that in the convex portion of the low convex portion region, the thermal conductivity was suppressed due to the relatively low convex portion. As described above, by providing the high-convex region as shown in Test Examples 1 to 4 and the low-convex region as shown in Test Examples 5 to 8 in a single casting and wrapping member, the adhesion and the adhesion greatly differ. It is possible to provide a member for casting and wrapping having a region having thermal conductivity.

1: Linear part 1a, 1b, 1c, 1d, 1e: Linear part 2: Collecting part 2a, 2b, 2c, 2d: Collecting part 3: Mesh-like convex part 3a: High convex part region 3b: Low convex part Area 6: Bottom surface (flat surface) of the convex part
35i, 35ma, 35mb, 35fa, 35fb: Crack D: Reference inner diameter Da: Non-reference inner diameter region Db: Reference inner diameter region Ea: High crack region Eb: Low crack region La: Length in the longitudinal direction of the linear portion Lb: Line Length (width) of the shaped part in the lateral direction
h3: Height of convex portion h9: Thickness to flat surface of cast-wrapping member ha: Height of convex portion in high convex portion region hb: Height of convex portion in low convex region region F: Flat surface Ic: Inscribed circle Circle

Claims (6)

A member for casting and wrapping having a mesh-like convex portion and a flat surface on the surface to be cast and wrapped.
The mesh-like convex portion comprises a linear portion and an aggregate portion where at least two linear portions are confluent.
The convex portion comprises a vertical wall portion that rises from the flat surface.
a) The convex portion has a shape having the vertical wall portion and the top portion, and the width of the top portion is larger than the width of the vertical wall portion, and / or.
b) The height of the convex portion has a shape that is randomly different.
The height of the convex portion of the linear portion from the flat surface is relatively high, and the height of the convex portion of the linear portion is relatively low, that is, the height of the convex portion of the linear portion is relatively low. A member for casting and wrapping, which comprises a part area. The casting / wrapping member according to claim 1, wherein the casting / wrapping member has a cylindrical shape and has a high convex portion region and a low convex portion region along the axial direction or the circumferential direction of the cylindrical shape. 2. The described casting and wrapping member. The casting package according to any one of claims 1 to 3, wherein the difference between the height of the convex portion in the high convex portion region and the height of the convex portion in the low convex portion region is 0.1 mm or more. Materials. The process of applying the mold to the surface on which the molten metal of the mold is to be poured, and
A step of drying the applied coating agent to form a coating layer having a crack shape on the surface, and a step of forming the coating layer.
It includes at least a step of pouring molten metal from the coating layer and casting while rotating the mold.
The surface on which the molten metal of the mold is to be poured has at least two different height regions, whereby the coating layer has a relatively thick region and a thin region. death,
The crack is a method for manufacturing a member for casting, in which the width of the crack is relatively large and the depth is deep in the thick region, and the width of the crack is relatively small and the depth is shallow in the thin region. A claim that controls the wide, deep and deep cracks formed in the thick region of the coating layer so that the crack depth is shallower than the thickness of the coating layer in the thin region. 5. The method for manufacturing a member for casting and wrapping according to 5.

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