CN109807299B

CN109807299B - Insert casting member and method for manufacturing same

Info

Publication number: CN109807299B
Application number: CN201811390573.4A
Authority: CN
Inventors: 铃木延明; 水村雄一; 长泽谅; 久冈未来; 山元昭人
Original assignee: Suzuki Motor Corp
Current assignee: Suzuki Motor Corp
Priority date: 2017-11-21
Filing date: 2018-11-21
Publication date: 2021-05-28
Anticipated expiration: 2038-11-21
Also published as: FR3073760A1; DE102018127485A1; JP2019093408A; JP7039953B2; CN109807299A

Abstract

Provided is an insert casting member in which shear stress generated on an insert casting surface is effectively dispersed. An insert casting member having, on a surface to be insert cast, a mesh-like convex portion (3), a bottom surface portion (F) surrounded by the convex portion, and individual protrusions (5a, 5b), wherein the convex portion includes a vertical wall portion and a top portion rising from the bottom surface portion, the top portion has a width larger than that of the vertical wall portion, at least a part of the bottom surface portion is a substantially flat surface, the individual protrusions are pin-like protrusions rising from at least a part of the bottom surface portion, and when the mesh-like convex portion is projected onto a plane, the convex portion forms a collective portion where a linear portion and at least 2 linear portions are joined.

Description

Insert casting member and method for manufacturing same

Technical Field

The present invention relates to an insert casting member and a method for manufacturing the same. The present invention particularly relates to an insert casting member for vibration damping and a method for manufacturing the same.

Background

In the molding of a cylinder block (hereinafter, also referred to as C/B) which is a central component of an automobile, a die casting method with high productivity is used, and accordingly, a sleeve on which a piston slides is simultaneously insert-cast with aluminum at the time of die casting.

Conventionally, a sleeve insert-cast in die casting has been used which has a single convex protrusion with a tapered tip on the outer peripheral surface of the sleeve (see, for example, patent documents 1 and 2). These contribute to the following excellent engine performance: the adhesion between the cylinder and the sleeve and the joint strength (adhesion strength) are improved, the reduction of residual stress in the portion between the inner holes (bores) is suppressed, the reduction of adhesion strength to aluminum in the radial direction is suppressed, and the heat diffusion during combustion is improved.

Recently, in order to enhance the steering comfort of a vehicle, in addition to C/B, there has been a demand for reducing sound and vibration generated from rotating members such as a brake drum, a transmission case shaft portion, and an aluminum hub, and an example of insert-casting a cast iron member for insert-casting into an aluminum drum body has been reported (for example, see patent document 3).

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 4429025

Patent document 2: japanese patent No. 4210468

Patent document 3: japanese unexamined patent publication No. 5-187466

Disclosure of Invention

Problems to be solved by the invention

In the engine of today, there is a high demand for miniaturization due to the thinning of the sleeve. Under such circumstances, for example, in the conventional techniques disclosed in

patent documents

1 and 2, a reduction in rigidity due to thinning of the sleeve becomes a serious problem. This is because the sleeve is exposed to a high injection pressure of the molten aluminum during die-casting, and receives a strong fastening load from the bolt when fastening the C/B and the cylinder head (hereinafter also referred to as C/H), which tends to cause large compression deformation.

In the aluminum rotary component including the cast-in member disclosed in patent document 3, since the young's modulus of the cast-in cast iron member and that of aluminum are greatly different from each other, high shear stress is locally generated at the cast-in interface due to high rotational torque applied during braking, and there is a possibility that aluminum is plastically deformed in a local region near the interface.

Therefore, if a new sleeve structure capable of further improving rigidity and dispersing stress caused by external force can be created, it is expected to prevent deterioration of noise, vibration, and harshness (NVH) characteristics in the inner hole peripheral portion.

Means for solving the problems

As a result of intensive studies, the inventors of the present invention have found an insert casting member having a continuous mesh-like convex portion on an insert casting surface and having a structure effective for reducing deformation and stress, and a method for manufacturing the same, and have solved the above problems.

[1] According to one embodiment, the present invention relates to an insert casting member having a mesh-like convex portion, a bottom surface portion surrounded by the convex portion, and a single protrusion portion on a surface to be insert cast,

the convex portion includes a vertical wall portion rising from the bottom surface portion and a top portion having a width larger than that of the vertical wall portion,

at least a part of the bottom surface portion is a substantially flat surface,

the individual protrusions are pin-shaped protrusions rising from at least a part of the bottom surface portion,

when the mesh-like convex portions are projected onto a plane, the convex portions form a collective portion where linear portions and at least 2 linear portions meet.

[2] According to another embodiment, the present invention relates to an insert casting member having a mesh-like convex portion on a surface to be insert cast and a bottom surface portion surrounded by the convex portion,

at least a part of the bottom surface portion is a convex surface bulging toward the outer circumferential direction of the surface to be insert-cast,

[3] According to still another embodiment, the present invention relates to an insert casting member having a mesh-like convex portion, a bottom surface portion surrounded by the convex portion, and a single protrusion portion on a surface to be insert cast,

the convex portion has vertical wall portions rising from the bottom surface portion and having randomly different heights,

at least a part of the bottom surface portion is a substantially flat surface,

[4] According to still another aspect, the present invention relates to an insert casting member having a mesh-like convex portion on a surface to be insert cast and a bottom surface portion surrounded by the convex portion,

[5] Preferably, in the insert casting member according to item [2] or item [4], the bottom surface portion of the convex surface includes a pin-shaped separate protrusion rising from the bottom surface portion.

[6] Preferably, in the insert casting member according to any one of the above items [1], [3], or [5], the pin-shaped protrusion is

(a) A tapered pin-shaped protrusion having a tip end portion with a diameter smaller than that of the root portion, the height of the protrusion being 0.1mm or more and less than 0.5mm, and/or

(b) A half-dome shaped protrusion.

[7] Preferably, in the insert casting member according to any one of the above items [1], [3], [5] and [6], 1 to 10 individual protrusions are provided on 1 bottom surface portion surrounded by the convex portion.

[8] In the insert casting member according to any one of the above [1] to [7], preferably, when the mesh-like projected portions are projected on a plane, a projected area of the projected portions is 5% or more and 70% or less with respect to an entire projected area.

[9] In the insert casting member according to any one of [1] to [8], preferably, when the mesh-like convex portions are projected on a plane, a diameter of an inscribed circle that is tangent to a contour of a portion surrounded by the linear portion and the collective portion is 0.5mm or more and 30mm or less.

[10] Preferably, in the insert casting member according to any one of the above [1] to [9], the height of the mesh-like projected portion is 0.1mm to 5.0 mm.

[11] Preferably, in the insert casting member according to any one of the above [1] to [10], a length of the linear portion in a width direction is 0.1mm to 8.0 mm.

[12] Preferably, in the insert casting member according to any one of the above [1] to [11], the insert casting member is a cylinder liner, a brake sliding member, a bearing member, or a bicycle hub.

[13] According to another aspect, the present invention relates to a method for manufacturing a cast-in member, including at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

drying the coated die coating agent to form a die coating layer having a cracked shape and a recess on the surface; and

a step of casting while rotating the mold by allowing a melt to flow from the coating layer,

the crack is formed by a plurality of gaps extending from the surface of the coating layer to the surface of the mold, the width of the gap is formed to become narrower from the surface of the coating layer toward the surface of the mold, and at least a part of the gap extends along the surface of the mold,

the recess is pin-shaped and does not reach the surface of the mold.

[14] According to still another aspect, the present invention relates to a method for manufacturing a cast-in member, including at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

drying the coated die coating agent to form a die coating layer having a cracked shape on the surface; and

the center of at least a part of the region defined by the crack of the coating layer is recessed from the peripheral portion.

[15] According to still another aspect, the present invention relates to a method for manufacturing a cast-in member, including at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

drying the coated die coating agent to form a die coating layer having a cracked shape and a recessed portion on the surface; and

the cracks are formed by a plurality of gaps extending from the surface of the coating layer to the surface of the mold, the width of the gaps is formed to become narrower from the surface of the coating layer toward the surface of the mold, and the depths of the gaps are formed to be uneven,

the recessed portion is pin-shaped and does not reach the surface of the mold.

[16] According to another aspect, the present invention relates to a method for manufacturing an insert casting component, including at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

[17] Preferably, in the method for manufacturing an insert casting member according to any one of the above items [13] to [16], the crack has a mesh-like shape.

[18] Preferably, in the method for producing an insert casting member according to any one of the above [13] to [17], the coating agent includes at least a refractory, a binder, and a solvent.

[19] Preferably, in the method for manufacturing an insert casting member according to any one of the above [13] to [18], in the step of forming the coating layer, the coating agent is heated at a temperature not lower than an evaporation temperature of the solvent and not higher than a temperature higher than the evaporation temperature by 110 ℃.

Effects of the invention

The insert casting member of the present invention can reduce shear deformation and compression deformation at an insert casting interface of a product obtained by insert casting aluminum or the like, and can improve vibration damping property, and can prevent deterioration of NVH characteristics. Further, by providing the surface of the insert casting member to be insert cast with a predetermined shape, the contact area with the insert cast aluminum can be increased, and the thermal conductivity relating to the heat transfer and the heat diffusion from the insert casting member to the aluminum can be improved.

Drawings

Fig. 1is a perspective view conceptually showing one example of a cylinder sleeve.

Fig. 2 is a schematic enlarged view of a region d1 in fig. 1, and is a perspective view conceptually showing a surface to be cast in of the casting-in member according to embodiment 1 of the present invention.

Fig. 3 is a schematic enlarged view of the surface to be insert-cast of the cylinder sleeve similar to fig. 1, and is a perspective view conceptually showing the surface to be insert-cast of the insert-casting member according to embodiment 2 of the present invention.

Fig. 4 is a sectional view conceptually showing one example of a cylinder block.

Fig. 5 is a plan view of a part of the surface to be cast in the insert casting member according to embodiment 1 of the present invention.

Fig. 6 is a view showing a section a-a' of fig. 5.

Fig. 7 is an enlarged sectional view of the taper pin-shaped individual protrusions in fig. 6.

Fig. 8 is an enlarged sectional view of the half dome-shaped individual protrusions in fig. 6.

Fig. 9 is a sectional view schematically showing a convex portion having a narrowed shape.

Fig. 10 is a view showing a section B-B' of fig. 5, and is a view schematically showing a convex portion including a vertical wall portion.

Fig. 11is a 12-fold electron micrograph of a part of a surface to be cast in of the casting-in member according to embodiment 1 of the present invention.

Fig. 12 is a plan view of a part of the surface to be cast in the insert casting member according to embodiment 2 of the present invention.

Fig. 13 is a view showing a section D-D' of fig. 12.

Fig. 14 is a 20-fold electron micrograph of a part of a surface to be cast in of the casting-in member according to embodiment 2 of the present invention.

Fig. 15A to 15H are views for explaining a method of manufacturing an insert casting member according to the present invention.

Fig. 16A to 16D are diagrams illustrating a mechanism of forming a coating layer in the method for manufacturing an insert casting member according to the present invention.

Fig. 17 is a view schematically showing an insert casting member obtained by using the die coating layer described in fig. 16A to 16D.

Fig. 18A to 18D are diagrams for explaining the stress generated at the insert-casting interface and the effect of reducing the stress when the insert-casting member is a cylinder sleeve cast into the engine block.

Fig. 19A to 19D are diagrams illustrating stress generated at an insert casting interface and an effect of reducing the stress in a case where an insert casting member is a sliding member that contacts a brake shoe in a drum brake cast with aluminum.

Fig. 20 is a photograph showing an electron micrograph of the insert casting member obtained in example 2.

Fig. 21 is a view showing an electron micrograph of a cross section of the insert casting member obtained in example 4.

Description of the reference numerals

11 sleeve

12 aluminium

10 cylinder block

3 convex part

51 taper pin-like individual protrusions

52 individual protrusions in the shape of half-domes

F a bottom surface portion having a substantially flat surface

C has a convex bottom surface

4 vertical wall part

7, top.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail, but the scope of the present invention is not limited to these embodiments.

According to one embodiment, the invention relates to a component for insert casting. Examples of the material of the cast-in member include metals having a high specific gravity, a self-sliding property, and a high damping coefficient, such as cast iron, a copper alloy, tin, and a zinc alloy. Among them, cast iron is generally a ternary alloy containing iron, carbon and silicon, and is more suitable because it is an alloy containing graphite crystals having excellent self-sliding properties and also has excellent vibration damping properties. For example, as long as it is cast iron, its components may include, in addition to Fe: the cast iron comprises 3.1 to 3.8 mass% of T.C (Total Carbon), 1.9 to 2.5 mass% of Si, 0.5 to 1.0 mass% of Mn, 0.01 to 0.5 mass% of P, and 0.02 to 0.1 mass% of S, based on the Total mass of the cast iron.

The shape of the insert casting member main body is not particularly limited, and can be appropriately selected according to the application. Examples of the shape include a cylindrical shape, a semi-cylindrical shape, a shape having a cross section in a shape of コ letter or t letter, a curved surface, a substantially planar plate shape, and the like. Examples of the members for insert casting include cylinder sleeves cast into engine cylinder blocks, annular sliding members in contact with brake shoes cast into aluminum drum brakes in regenerative brakes for EV vehicles, hybrid vehicles, and the like, bosses (boss) of die-cast hubs for two-wheeled vehicles and special machines, and members cast into some die-cast parts such as crank journals of cylinder blocks, lower crank cases, transmission cases, bearing portions of housings of electric motors, and the like. The present invention will be described below by taking a cylindrical cylinder sleeve as an example, but the present invention is not limited to a specific insert casting member or a specific product.

Fig. 1is a conceptual perspective view of a cylinder sleeve 11 as an example of an insert casting member. The cylinder sleeve 11is a cylindrical structure defined by an inner surface 11is and an outer surface 11s, and the outer surface 11s is a surface cast with metal such as aluminum. Fig. 2 is an example of a schematic perspective view of an enlarged region denoted by d1 in fig. 1, and is a schematic perspective view of the insert casting member according to embodiment 1 of the present application. The cylinder sleeve has a mesh-like convex portion 3, a bottom surface portion F, and

individual protrusions

5a and 5b on an insert-molded surface 11 s. The mesh-like projections 3 are projected from the bottom surface F, and are continuous and present over the entire surface to be insert-cast. Fig. 3 is an example of a schematic perspective view in which a region of a surface to be insert-cast of the cylinder sleeve similar to fig. 1is enlarged, and is a schematic perspective view of an insert-casting member according to embodiment 2 of the present application. The structure of the mesh-like projections 3 is substantially the same as that of fig. 2. On the other hand, in fig. 3, the bottom surface portion C surrounded by the mesh-like convex portions 3 has a convex structure in which the central portion protrudes from the peripheral portion.

Next, the cylinder sleeve will be schematically described. Fig. 4 is a conceptual diagram illustrating an example of a cylinder block having a cylinder sleeve as a component. The cylinder block 10 is cast by insert casting aluminum 12 on the outer peripheral surface of a cylinder liner 11.

[ embodiment 1: cast-in member

According to embodiment 1, the present invention is an insert casting member. The insert casting member of the present embodiment has, on a surface to be insert cast, a mesh-like convex portion, a bottom surface portion surrounded by the convex portion, and individual protrusions, at least a part of the bottom surface portion being a substantially flat surface, the individual protrusions being pin-like protrusions rising from at least a part of the bottom surface portion, and when the mesh-like convex portion is projected onto a plane, the convex portion forms an aggregate portion where linear portions and at least 2 linear portions are joined. In embodiment 1 of the present invention, the convex portion includes a vertical wall portion rising from the bottom surface portion and a top portion, and the top portion has a width larger than that of the vertical wall portion. In embodiment 1 and embodiment 2, the convex portion includes vertical wall portions rising from the bottom surface portion and having different heights at random.

Fig. 5 is a plan view of a surface to be cast in of the casting-in member according to embodiment 1, as viewed from a vertical direction of the surface, and fig. 6 is a sectional view a-a' of fig. 5. In the case of the cylinder sleeve 11 shown in fig. 1, the surface 11s to be cast in of the casting member corresponds to the outer peripheral surface.

The convex portions 3 have a mesh-like structure composed of linear portions 31 and collective portions 32 when the surface to be cast-in is viewed from the outer circumferential direction thereof in plan view. The linear portion 31 is a portion where the convex portion 3 can be confirmed to have a linear or strip shape having a width. The linear portion 31 may be a straight line or a curved line, or may be an indefinite shape having a non-uniform width, length, or height. The length of the linear portion 31 in the longitudinal direction La is not particularly limited. The length of the linear portion 31 in the short side direction, that is, the length Lb of the top portion of the linear portion in the width direction is preferably 0.1mm or more and 8.0mm or less, more preferably 0.1mm or more and 5.0mm or less, and still more preferably about 0.2mm or more and 3.0mm or less. The length of the linear portion 31 in the short side direction corresponds to the width in the case of being projected onto a plane. If the thickness is less than 0.1mm, the anchoring effect on the cast-in aluminum and the effect of the linear portion 31 in suppressing the deformation of aluminum may be insufficient. If the thickness exceeds 8.0mm, the weight may not be reduced sufficiently. By setting the length of the top portion of the linear portion 31 in the width direction to the above range, a more amount of the intersection (hub) portion which becomes the collective portion 32 where the linear portions 31 converge can be secured. The length of the top surface of the linear portion 31 in the width direction can be measured using, for example, a digital microscope, and for example, 1 to 50 points can be measured, and a range including the measured values can be obtained based on the average value or the minimum value and the maximum value thereof, and preferably, a range including all the measured values can be obtained. Further, the length Lb in the width direction of the top portion of the linear portion may be different between the 1 st aspect in which the convex portion has a narrowed cross section and the 2 nd aspect in which the convex portion is formed of a vertical wall portion. The details will be described later.

In fig. 5, the collective portion 32a is formed by merging 3

linear portions

31a, 31b, 31 c. The number of the linear portions 31 merged into the collective portion 32 is not particularly limited, but is at least 2, and preferably 2 or more and 6 or less. Preferably, the mesh-like projections 3 include at least 2 collecting portions 32. When the mesh-like projection 3 has 2 or more collection portions 32, the number of linear portions 31 joined to each collection portion 32 may be the same or different. The mesh-like projections 3 formed on the outer peripheral surface of the insert casting member bring about an effect of reinforcing ribs for improving the rigidity of the insert casting member. Further, since the collective portion 32 disperses stress generated by an external force at the time of insert casting, the linear portions 31 preferably merge with each other in random directions. The linear portions 31 merging with each other in random directions means that, for example, 2 linear portions 31 are not parallel but merge with the collective portion 32 in different directions.

The bottom surface F is a portion surrounded by the

linear portions

31a, 31b, 31d, 31e and the

collective portions

32a, 32b, 32c, 32d of the convex portion 3 in a plan view. On the other hand, referring to fig. 6, the bottom surface F is a portion defined by a substantially flat surface substantially parallel to the inner surface 11is of the insert casting member. In the present specification, the substantially flat surface means a surface having substantially no difference in thickness between the central portion and the peripheral portion of the bottom surface portion F, or having a difference in thickness of less than about 100 μm, unlike the convex surface. The peripheral portion of the bottom surface F is a portion where the convex portion 3 rises, and the central portion is a portion separated from at least the peripheral portion. In the partial structure shown in fig. 5 and 6 of the insert casting member according to the present embodiment, the convex portions 3 form continuous mesh openings without gaps, and a region surrounded by the convex portions 3 and the bottom surface portion F is formed. In this specification, this region is referred to as a cell (cell). The cell is not limited to the region completely surrounded by the continuous convex portions 3, and may be similarly regarded as a cell by partially interrupting the convex portions 3, for example, by complementing the interrupted portions with virtual extended lines in a plan view. In fig. 5 and 6,

separate protrusions

5a, 5b are formed within the cell. The

individual protrusions

5a and 5b are pin-shaped protrusions having a substantially circular shape in a plan view, unlike the continuous protrusion 3. Preferably, 1 or more and 10 or less

individual protrusions

5a and 5b, and more preferably 1 or more and 6 or less individual protrusions are provided for each 1 unit. However, among a plurality of cells present in the entire insert casting member, there may be a cell in which no individual protrusion is present. The shape of the individual protrusions included in 1 unit may be the same or different.

The individual protrusions substantially have a taper pin-shaped individual protrusion 5a and a half dome-shaped individual protrusion 5 b. Fig. 7 is an enlarged view of the individual protrusion 5a of fig. 6, showing a cross section of the individual protrusion 5a in a tapered pin shape. The taper pin-shaped individual protrusion 5a is an individual protrusion in which the diameter R5a of the base portion of the protrusion rising from the bottom surface F is larger than the diameter of the tip end portion of the pin, and the height h5a of the protrusion is approximately 2 times or more the diameter R5a of the base portion of the protrusion. The height h5a of the taper pin-shaped individual protrusion 5a is, for example, 0.1mm or more and less than 0.5mm, preferably 0.2mm or more and 0.4mm or less. If the height h5a of the individual protrusions is less than the above range, the effect of dispersing the shear stress at the cast-in interface and the heat dissipation effect may not be sufficiently exhibited. If the height h5a of the individual protrusions is higher than the above range, the filling property of aluminum into the cells is lowered during the production of the insert casting member, and voids are likely to be generated at the interface of the convex portions 3, which may result in a reduction in the performance of the insert casting member itself.

Fig. 8 is an enlarged view of the individual protrusion 5b of fig. 6, showing a cross section of the individual protrusion 5b in a half-dome shape. The individual projections 5b of the half-dome shape are projections having a height h5b less than about 2 times the diameter R5b of the root of the projection and having a tip substantially formed of a curved surface. The height h5b of the half-dome-shaped individual protrusions 5b is, for example, about 0.1mm to 0.5mm, preferably about 0.2mm to 0.4 mm.

Referring again to fig. 5, when the surface to be insert-cast is viewed from above in the vertical direction of the surface, an inscribed circle Ic can be drawn on the bottom surface portion F surrounded by the convex portion 3. The diameter of the inscribed circle Ic is preferably 0.5mm or more and 30mm or less, more preferably 1.0 to 15mm, and still more preferably 1.5mm to 5.0 mm. If the thickness is less than 0.5mm, the effective area in contact with aluminum during casting is insufficient, and it is difficult to effectively secure the anchoring effect to the cast aluminum, and the thermal conductivity may be insufficient. If it exceeds 30mm, the effective area in contact with aluminum after insert casting may be insufficient, and an effective network structure for dispersing stress caused by external force may not be formed. By setting the diameter of the inscribed circle to the above range, the effective area in contact with aluminum is sufficient at the time of insert casting, thermal conductivity is good when used as an insert casting member, and the net structure can disperse stress. In the case where the insert casting member has a cylindrical shape, for example, the diameter of the inscribed circle may be determined by creating an inscribed circle on the bottom surface F based on an image obtained by correcting a photographed image of the convex portion 3 on the curved surface on a plane using a digital microscope, for example, and obtaining an average value from 1 to 50 inscribed circles, or may be determined by determining a range including the measured values based on the minimum diameter and the maximum diameter, and preferably, by determining a range including all the measured values. The present invention is not limited to the form in which the entire flat portion is surrounded by the linear portion. In this case, the inscribed circle can be drawn along several linear portions, and the diameter thereof can be processed in the same manner as described above.

When the surface to be cast of the casting-in member is projected onto a plane from the vertical direction, the projected area of the mesh-like projected portions 3 onto the plane is preferably 5% or more and 70% or less, more preferably 10% or more and 60% or less, and still more preferably 16% or more and 43% or less, with respect to the entire projected area. If the ratio is less than 5%, the effective area in contact with aluminum may be insufficient during insert casting, and the effect of the reinforcing rib as a stress reducing member by external force may be reduced. If the content exceeds 70%, the effect of weight reduction may not be exhibited. By setting the projected area of the mesh-like projected portions 3 to the above-described range with respect to the entire projected area, it is possible to secure adhesion strength to the metal to be cast, heat transferability, and heat diffusibility at the time of casting, and to improve rigidity, and also to improve thermal conductivity and specific elastic modulus as a cast-in member after casting. The projected area may be calculated by, for example, photographing with a microscope and performing binarization processing based on the image after the plane correction, and may be calculated, for example, by an average projected area ratio of the convex portions based on the measurement results of 1 to 50 points, or may be calculated based on the minimum value and the maximum value of the area ratio, or may be calculated as a range including the measurement values thereof, or preferably, may be calculated as a range including all the measurement values thereof. The mesh-like projections 3 are continuously formed on the surface of the insert casting member. The term "continuously" is not limited to a form in which all the linear portions are connected, but includes a form in which only a part of the linear portions are connected.

In the present embodiment, the cross-sectional shape of the convex portion 3 can be roughly classified into 2 types. The cross-sectional shape referred to herein is a cross-sectional shape in a direction perpendicular to the surface to be cast in and perpendicular to the longitudinal direction of the linear portion. In the embodiment shown in fig. 5 and 6, the convex portion 3a of the 1 st aspect having a narrowed cross section and the convex portion 3b of the 2 nd aspect composed of a vertical wall portion are mixed. However, the insert casting member of the present invention may be provided with only the projection 3a of the 1 st aspect, may be provided with only the projection 3b of the 2 nd aspect, or may be a mixture of both. When the projections are mixed, the projections 3a of the 1 st aspect and the projections 3b of the 2 nd aspect may be present in the projections constituting the same unit.

The convex portion 3a of embodiment 1 will be explained. Fig. 9 is a schematic enlarged view of a cross section of a convex portion (linear portion) with a narrowed shape. Referring to fig. 9, the convex portion 3a includes: a vertical wall portion 7 extending substantially vertically from the bottom surface portion F; and a top portion 4. In the illustrated cross section, the vertical wall portion 7 has a substantially constant width L7 from the bottom surface portion F to the vicinity of the top portion 4, and the top portion 4 has a width L4 larger than that of the vertical wall portion 7. Such a shape can be referred to as having a narrowed shape. However, the narrowed shape is not limited to the form shown in fig. 9, and the width of the vertical wall portion may not be fixed. Further, as in the case of the convex portion 3a shown in fig. 6, the width may be continuously increased from the vertical wall portion to the top portion, or as shown in fig. 9, a corner portion E where the vertical wall portion 7 and the top portion 4 contact at a predetermined angle may be formed. The width L4 of the top portion 4 corresponds to the width Lb of the linear portion described with reference to fig. 5. By configuring the surface of the insert casting member to have the above shape, the molten metal is detoured to, for example, a corner E having a narrowed shape, particularly an undercut (undercut) shape formed by the vertical wall portion 7 and the ceiling portion 4 when the insert casting member is cast, so that the anchoring effect can be improved, and the occurrence of a gap between aluminum and the insert casting member when an external force is applied can be suppressed.

The cross-sectional shape shown in fig. 9 may be referred to as a substantially T-shape or a substantially Γ -shape. In the convex portion having a substantially T-shaped cross section, the vertical wall portion may contact the top portion of the convex portion at a position equally dividing the top portion. On the other hand, the vertical wall portion may contact the top portion at a position not equally dividing the top portion. The top of the projection may be shaped so as to taper toward the end, or may have a constant thickness over substantially the entire range. The vertical wall portion may have a substantially constant width from the vicinity of the bottom portion to the vicinity of the top portion in the cross-sectional view, or may have irregularities on the side surface thereof. The vertical wall portion may be erected substantially perpendicularly to the substantially flat surface constituting the bottom surface portion F, or may extend obliquely at a certain degree from a perpendicular line to the substantially flat surface.

The height h3 of the projection 3a can be represented by the sum of the height h4 of the top 4 and the height h7 of the vertical wall 7. The height h3 of the convex portion 3a may be substantially constant along the longitudinal direction La of the linear portion 31, but may be partially different. The height h3 of the projection is preferably 0.1mm or more and 5.0mm or less, more preferably 0.1mm to 3mm, and still more preferably 0.5mm or more and 1.5mm or less. If the thickness is less than 0.1mm, the anchoring effect on the cast-in aluminum may be insufficient, and the effect of the reinforcing rib for improving the rigidity may be reduced. Further, the contact area with aluminum necessary for heat diffusion may be insufficient. If the height h3 of the projection 3a exceeds 5.0mm, it may become difficult to form the projection by centrifugal casting. By setting height h3 of projection 3a within the above range, the effective area of contact with the metal to be cast can be increased, and the thermal diffusivity can be improved. The height h3 of the projection 3a can be obtained by line analysis of any surface of the insert casting member using, for example, the measurement function of a digital microscope and image analysis software WinROOF2013, and an average value can be obtained. Alternatively, the cross section may be observed with a digital microscope, and a range including the measurement value may be obtained based on the minimum height and the maximum height of each projection 3a from the bottom surface F in an arbitrary measurement region, and preferably, a range including all the measurement values may be obtained.

Next, the convex portion 3b of the 2 nd embodiment will be explained. The convex portion 3b of the 2 nd embodiment includes vertical wall portions whose heights are randomly different along the longitudinal direction of the linear portion 31. The convex portion 3b of the 2 nd embodiment has a structure including a vertical wall portion without a wide top portion. The cross-sectional shape may be, for example, a shape whose width is narrowed from the bottom surface F to the tip portion, as exemplified by the convex portion 3b in fig. 6. Or may have a shape in which the width is substantially constant or non-constant from the bottom surface F to the top end portion. The height h3 of the convex portion 3b varies randomly along the longitudinal direction of the linear portion. Fig. 10 is a sectional view taken along line B-B' of the linear portion 31a of fig. 5. The linear portion 31a in fig. 5 is the convex portion 3b of the 2 nd embodiment, and the height h3 is different along the longitudinal direction of the linear portion 31a, and there are a portion where the height h3 of the convex portion is low and a portion where it is high at random. The convex portion 3b of the 2 nd aspect has a length Lb in the width direction of the linear portion smaller than the length Lb in the width direction of the linear portion in the convex portion 3a of the 1 st aspect, preferably 0.1mm to 3.0mm, and more preferably 0.2mm to 2mm, when the surface to be cast is viewed from the outer peripheral direction thereof in plan view.

Further, since the insert casting member of the present embodiment has a convex portion of various shapes on the surface to be insert cast, which can be produced by a production method described later, there may be a convex portion having a cross-sectional shape other than the cross-sectional shapes described in

embodiments

1 and 2.

The overall appearance of the insert casting member is: the convex portions 3 have a mesh shape like a surface pattern of a melon, and a space surrounded by the convex portions 3 is provided with individual protruding portions; and/or at least a part of the bottom surface portion is a convex surface bulging toward the outer peripheral direction of the surface to be cast-in. Referring again to FIG. 1, the thickness 11b of the casting insert member is preferably 2 to 20 mm. For example, in fig. 6, the thickness of the casting insert member is the sum of the thickness h9 from the inner peripheral surface of the casting insert member to the surface of the bottom surface F and the height h3 of the mesh-like protrusions, and the height h3 of the protrusions is preferably 1 to 70%, more preferably 10 to 50%, of the thickness of the casting insert member.

Fig. 11is a 12-fold electron micrograph of the cast-in surface of the cast-in member according to embodiment 1. The mesh-like convex portions 3 and the individual protrusions 5a are clearly seen in fig. 11.

[ embodiment 2: cast-in member

According to embodiment 2, the present invention is an insert casting member. The insert casting member according to the present embodiment has a mesh-like convex portion and a bottom surface portion surrounded by the convex portion on a surface to be insert cast, at least a part of the bottom surface portion is a convex surface bulging in an outer circumferential direction of the surface to be insert cast, and when the mesh-like convex portion is projected onto a plane, the convex portion forms a collective portion where a linear portion and at least 2 linear portions are joined. In embodiment 1 of embodiment 2, the protruding portion includes a vertical wall portion rising from the bottom surface portion and a top portion, and the top portion has a width larger than that of the vertical wall portion. In embodiment 2, the protruding portion is configured to include vertical wall portions rising from the bottom surface portion and having randomly different heights in embodiment 2.

Fig. 12 is a plan view of a surface to be cast in of the casting insert member according to embodiment 2, as viewed from a vertical direction of the surface, and fig. 13 is a cross-sectional view of D-D' of fig. 12. The surface to be cast of the casting-in member includes a bottom surface portion C and a convex portion 3. The convex portion 3 is erected from the bottom surface portion C in the outer peripheral direction O of the surface to be insert-cast. In addition, the convex portions 3 have a mesh structure composed of linear portions 31 and collective portions 32 in a plan view.

In the present embodiment, the planar shape and the cross-sectional shape of the projection 3 can be provided with various modifications described in embodiment 1, as in embodiment 1, and therefore, the description thereof is omitted here.

Referring to fig. 12 and 13, the bottom surface portion C is a substantially flat surface, but the bottom surface portion C is a convex surface whose central portion bulges in the outer peripheral direction of the surface to be insert-cast than the peripheral portion. Here, the term "the central portion bulges outward in the peripheral direction as compared with the peripheral portion" means that, in 1 unit, the maximum thickness hc1 from the inner peripheral surface of the insert casting member to the central portion of the bottom surface portion C is larger than the minimum thickness hc2 from the inner peripheral surface of the insert casting member to the peripheral portion of the bottom surface portion C, and the difference hc1-hc2 is 0.1mm or more, and is convex in the peripheral direction of the surface to be cast. The periphery of the bottom surface C is a root portion of the projection 3, and the central portion is a portion separated from at least the periphery. In the present specification, the bottom surface portion C including the convex surface bulging in the outer circumferential direction of the surface to be insert-cast defined as above is also referred to as a convex bottom surface portion C.

The convex bottom surface portion C may be provided in at least some of the plurality of cells included in the insert casting member, and is preferably provided in, for example, 10% or more, more preferably 30% or more. Therefore, in the insert casting member according to embodiment 2 as well, as in embodiment 1, the bottom surface portions of some of the cells may be formed of substantially flat surfaces.

According to the modification of embodiment 2, the single protrusions rising from the convex bottom surface portion C may be provided, and the single protrusions 5a may be tapered pin-shaped, the single protrusions 5b may be semi-dome-shaped, or a mixture of them may be provided. In addition, in the modification of embodiment 2, the unit having the substantially flat bottom surface may include the

individual protrusions

5a and 5b rising from the substantially flat bottom surface. When there are individual protrusions, the preferred shape, size, number, and the like thereof may be the same as those of embodiment 1. Although the height of the convex portion 3 and the

individual protrusions

5a and 5b in embodiment 1is defined as the height from the substantially flat bottom surface F, the height of the convex portion 3 in the present embodiment is defined with reference to the root of the convex portion 3, and the height of the

individual protrusions

5a and 5b is defined with reference to the convex bottom surface C.

Fig. 14 is a 20-fold electron micrograph of the cast-in surface of the cast-in member according to embodiment 2. The mesh-like convex portions 3 and the convex bottom surface portions C are clearly seen in fig. 14. In addition, the height of the convex portions 3 was observed to be randomly different along the longitudinal direction of the linear portion. In addition, it can be seen that a plurality of minute concave holes are formed in the vertical wall side surface of the mesh-like convex portion 3. Since the cast-in aluminum melt is also inserted into the minute concave hole, the close contact interface between the cast-in member and aluminum becomes multidimensional, and the cast-in member is less likely to peel off even if an external force acts such as shearing and compression, and contributes to improvement in the strength of the cast-in member itself.

Here, in the insert casting members according to

embodiments

1 and 2 of the present invention, insert casting is performed using aluminum, an aluminum alloy, or another nonferrous alloy. A member obtained by insert-casting the insert-casting member with such a metal or alloy is referred to as an insert-cast member. As described above, the insert casting member has good adhesion to a metal or alloy such as aluminum to be cast, and also has good thermal conductivity as an insert casting member. The thermal conductivity can be measured by a laser flash method. For example, in the case where the insert casting member is a cylinder sleeve cast into an engine block, the cylinder sleeve is required to uniformly diffuse heat to a surrounding aluminum cylinder bore, and high rigidity is required to easily bear a combustion pressure and a compression load at the time of fastening a cylinder head. By applying the present invention to a cylinder sleeve and insert-casting the cylinder sleeve with aluminum, for example, an engine block having more excellent thermal conductivity and thermal diffusivity can be formed. Further, even if the compression ratio of the engine is increased, heat can be efficiently radiated from the cylinder liner to the aluminum cylinder tube, and an increase in combustion temperature due to high compression can be suppressed. Further, the specific modulus of elasticity of the cylinder sleeve can be increased, and therefore, if the same weight is used, deformation of the inner bore of the cast-in cylinder sleeve, that is, change in roundness can be prevented at the time of the above-described operation and fastening, mechanical loss of the engine and blowby gas can be reduced, and occurrence of sound, vibration, and the like can be suppressed. If the cylinder sleeve has the same rigidity, the thickness of the sleeve itself can be reduced and the weight of the sleeve itself can be reduced, and finally the weight of the engine can be reduced.

[ Note: from a prior application

[ embodiment 3: method for producing insert casting Member

In addition, according to embodiment 3, the present invention relates to a method for manufacturing a member for insert casting. The method of the present invention at least comprises the following steps: applying a coating agent to a surface of a mold into which a melt flows; drying the coated die coating agent to form a die coating layer having a cracked shape on the surface; and a step of casting while rotating the mold by allowing the melt to flow from the coating layer.

The material and shape of the mold for molding the insert casting member are not particularly limited, and may be selected according to the material and use of the intended insert casting member. For example, when a cylinder sleeve cast into an engine block is molded as an insert casting member, the mold is preferably a metal mold, and preferably has a cylindrical shape. In this case, the molding is preferably performed by a centrifugal casting method using a centrifugal force. The surface of the mold for molding the insert casting member may be, for example, a substantially smooth surface that is left as it is in a machined state.

Fig. 15A to 15H are views schematically illustrating a method of manufacturing an insert casting member according to an embodiment of the present invention. Fig. 15A schematically shows a liquid coating agent 62 prepared in a container 66. The coating agent 62 may include at least a refractory material, a binder material, and a solvent. In some cases, the aggregate may be contained.

The refractory is preferably a diatomaceous earth powder because it protects the surface of the mold, prevents the molten metal from being white and iron, and ensures sufficient releasability. The lower limit of the amount of the refractory is preferably 2 mass% or more, more preferably 8 mass% or more, and the upper limit is preferably 40 mass% or less, more preferably 27 mass% or less, and still more preferably 15 mass% or less, based on the mass of the entire coating agent.

Examples of the binder include bentonite, montmorillonite, kaolinite, sepiolite, attapulgite, and chamotte. Particularly, when the refractory and the aggregate are mixed together in the solvent, the viscosity capable of suppressing separation and adhering the coating agent to the surface of the mold is obtained, and therefore, bentonite which absorbs the solvent and swells and gels is preferable. The lower limit of the amount of the binder is preferably 2 mass% or more, more preferably 5 mass% or more, and still more preferably 8 mass% or more, and the upper limit is preferably 20 mass% or less, and more preferably 12 mass% or less, based on the mass of the entire die coating agent. If the amount is less than 2% by mass, separation from the refractory tends to occur, and the strength of the die coating layer may be insufficient, while if it exceeds 20% by mass, the viscosity of the slurry of the die coating agent may be too high to make it difficult to apply the die coating agent.

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

The coating agent may contain aggregate in addition to the above materials. As the aggregate, mineral powder including alumina and silica such as mullite and ceramsite (ceramides) or artificial ceramic sand may be used, and casting sand such as zircon sand, chromite sand, silica sand, olivine sand and spinel sand may also be used. In particular, mullite or ceramsite is preferable because it has a low specific gravity for preventing separation from the refractory or binder, does not absorb a solvent, and accelerates shrinkage of the coating layer during drying and curing to increase cracks in the coating layer. The lower limit of the amount of the aggregate is preferably 1.0 mass% or more, more preferably 1.5 mass% or more, and still more preferably 3.0 mass% or more, with respect to the mass of the entire coating agent, and the upper limit is not particularly limited, but is preferably 25 mass% or less, and more preferably 10 mass% or less.

At least the refractory, the binder and the solvent are mixed, and if necessary, an aggregate is further mixed to form a slurry-like coating agent.

Fig. 15B is a conceptual diagram of a step of applying a coating agent 62 to an inner circumferential surface 60, which is a surface of a mold 61 into which a melt flows. In the present embodiment, the surface to be flowed in (hereinafter also referred to as a melt contact surface) is preferably the inner circumferential surface 60 of the mold 61, and the surface is preferably substantially flat before the mold coating 62 is formed. In the coating step, the coating agent 62 is applied to the inner circumferential surface 60 of the mold using the nozzle 41 while rotating the cylindrical mold 61 in the fixed direction r.

The inner circumferential surface 60 of the mold when the mold is coated with the coating agent is preferably heated to a temperature at which the coating agent does not swell. The heating temperature is preferably 110 to 210 ℃, and more preferably 120 to 180 ℃.

Fig. 15C is a conceptual diagram of a step of drying the applied die coating agent to form a die coating layer having a cracked shape. It is preferable to rotate the mold 61 in the fixed direction r before drying the coating agent.

Drying of the coating agent can be carried out by keeping the mold in rotation after coating. The coating agent may be dried and cured while being kept heated or by the heat of the mold heated further. Alternatively, after stopping the rotation of the mold, the mold may be heated from the outside of the mold as necessary to shorten the drying and curing time.

When drying is performed by further heating after coating, it is preferable to heat at a temperature not lower than the evaporation temperature of the solvent but not higher than the evaporation temperature by 110 ℃. This can form a coating layer having a shape of a crack due to shrinkage of the coating agent 62 caused by drying and curing, while suppressing the solvent from swelling from the inside of the coating agent 62 and suppressing the generation of excessive bubbles (water vapor). The lower limit of the heating temperature is preferably not lower than the evaporation temperature of the solvent, more preferably not lower than 10 ℃ higher than the evaporation temperature of the solvent, and still more preferably 20 ℃ higher than the evaporation temperature of the solvent. The upper limit of the heating temperature is preferably not more than 110 ℃ higher than the evaporation temperature of the solvent, and more preferably not more than 80 ℃ higher than the evaporation temperature of the solvent.

The thickness of the coating layer 62 after drying is determined by the maximum protrusion height desired in the insert casting member, and the like, and is not particularly limited, but preferably has an average thickness of 0.1mm to 5.0mm, and more preferably has an average thickness of 0.5mm to 2.0 mm.

Next, a mechanism of forming the coating layer will be described with reference to fig. 16A to 16D. Fig. 16A schematically shows a stage in which a part of volatile components 63 is evaporated from the coating agent 62 applied to the heated mold 61. Fig. 16B shows an initial state when the coat layer 62 is dried and cured. In this stage, the volatile 63 is evaporated in a large amount from the coating layer 62, and shrinkage 64 starts to occur at random intervals on the surface of the coating layer 62, thereby generating cracks 65. Fig. 16C shows a middle stage state at the time of dry curing. The shrinkage 64 of the die layer 62 further progresses, and cracks 65 are generated which expand from the surface of the die layer 62 to the surface of the mold 61, and the cross section of the gap in the thickness direction of the die layer becomes wedge-shaped. In some cases, the cured product may be completely dried and cured in such a cracked state.

Fig. 16D shows a final state at the time of drying and curing. Cracks 65 penetrating the coating 62 are generated, and blocks defined by the cracks 65 are generated. The block becomes the following coating: there are cases where the blocks do not substantially contact each other or partially contact each other. Furthermore, the crack 65 develops further as the coating shrinks, particularly as the blocks shrink. The continuous crack from the surface of the coating layer 62 to the surface of the mold 61 becomes a mold for forming the mesh-like convex portions 3.

When a crack that further expands the void along the surface of the mold 61 is formed substantially perpendicular to an initially formed crack from the surface of the die coat 62 to the mold, the convex portion 3a of the 1 st aspect having a vertical wall portion and a top portion and having a narrowed structure is formed by the convex portion 3 formed by the die coat 62. The mold can be obtained by setting the drying and curing time to be relatively long in order to form cracks in the mold which are the projections 3a of embodiment 1.

On the other hand, when forming a crack that does not reach the surface of the mold 61 from the surface of the coating layer 62, the mold is mainly used for forming the convex portion 3b of the 2 nd aspect. The convex portion 3b of the 2 nd aspect is constituted by a vertical wall portion, and the height thereof is randomly different. Further, the mold can be obtained by setting the drying and curing time to be relatively short in order to form cracks in the mold which are the projections 3b of the 2 nd aspect. However, in the case of forming a crack in any of the systems, the conditions are affected by various factors, and therefore, specific conditions are determined by preliminary experiments or the like.

In one embodiment, the depressions 67 are formed by evaporation of moisture from the surface of the mold layer 62. The relatively deep ones of the recesses 67 serve as a mold for forming the individual tapered pin-shaped protrusions 5a described in embodiment 1. The relatively shallow recesses among the recesses 67 serve as a mold for forming the individual protrusions 5b having the half-dome shape described in embodiment 1. In order to form the depressions 67 of the mold which can be the individual protrusions, it is preferable that the molding temperature is relatively high and the thickness of the coating layer is relatively thin to reduce the amount of bentonite to a small extent among the above conditions. However, the formation of the depressions 67 depends on various other conditions, and is therefore not specified by the specific mold temperature, mold coating thickness, and bentonite amount. Therefore, the mold temperature, the thickness of the coating layer, and the amount of bentonite for forming the desired shape, size, and number of dimples 67 can be determined by preliminary experiments or the like.

In one embodiment, the wide-range depressions 66 formed by shrinkage of the entire block are formed on the surface of the mold layer 62 by evaporation of water from the surface of the mold layer 62. This is a mold for forming the convex bottom surface portion C of embodiment 2. In order to form the depressions 66 in a wide range, it is preferable that the mold temperature is relatively low, the thickness of the coating layer is relatively thick, and the amount of bentonite is slightly large, among the above conditions. However, the formation of a wide range of depressions 66 is dependent on various other conditions and is therefore not dictated by the particular mold temperature, mold coating thickness, and amount of bentonite. Therefore, the mold temperature, the thickness of the coating layer, and the amount of bentonite, which cause the dimples 66 to be formed in a wide range, can be determined by preliminary experiments or the like. In addition, when there is substantially no depression on the surface of the dried coating layer 62, a mold for forming the bottom surface portion F having a substantially flat surface can be obtained.

The surface of the thus obtained die coat 62 may have cracks having a mesh-like shape, and thereby an insert casting member having mesh-like protrusions 3 can be manufactured.

Referring again to fig. 15A to 15H, fig. 15D is a conceptual diagram illustrating a step of performing centrifugal casting while rotating the mold 61 in a fixed direction r by flowing the molten cast iron 43 from above the mold coat 62 into the mold 61. As in fig. 15B, the melt 43 can be poured into the inside of the cylinder by a melt supply mechanism such as a nozzle while rotating the mold 61. By rotating the mold 61, the melt 43 flows into the inside of the cracks of the mold coat 62 by centrifugal force, and the desired mesh-like projections 3 can be formed on the surface of the insert casting member.

Fig. 15E is a conceptual diagram of a step of solidifying the molten cast iron. The molten cast iron 43 is cooled from the outside of the mold 61 and solidified, thereby obtaining the cast-in member-type molded body 44. After casting the melt by flowing it into a mold, it may be naturally cooled and solidified. After the melt is solidified, the rotation of the mold is stopped.

Fig. 15F is a conceptual diagram illustrating a step of taking out the molded article 44 of the casting-in member type from the mold 61. The method for taking out the molded article 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 barrel-type mold, a chuck is attached to the inner diameter portion of the molded body 44, and the molded body can be extracted in the arrow direction 45 in the figure and taken out from the mold 61.

Fig. 15G is a conceptual diagram illustrating a process of removing the coating layer 62 from the molded body 44 taken out from the mold 61. The molded body 44 taken out from the mold may have a coating layer adhered to the surface thereof. The method for removing the die coat from the molded body 44 is not particularly limited, and shot blasting, water jet, dry ice cleaning, and the like can be mentioned.

Fig. 15H shows the insert casting member 48 after the mold coating is removed from the molded body. By removing the cured coating from the molded body, the insert casting member 48 having the mesh-like convex portions on the surface thereof can be obtained.

Fig. 17 is a view schematically showing an insert casting member formed of the mold coat 62 shown in fig. 16D. The convex portion 3, the individual protrusion 5a, and the convex bottom surface portion C are formed in accordance with the shape of the crack or the recess.

According to the present invention, the convex portion having a predetermined shape and a height that cannot be obtained by the conventional manufacturing method can be formed on the surface to be cast of the member for casting. Therefore, the aluminum alloy can have high adhesion strength with the cast aluminum. The insert casting member of the present invention can be applied to members other than sliding parts having high rigidity, excellent heat transfer properties, excellent heat diffusion properties, and excellent heat conductivity, and can be applied to an insert casting member of a portion where a rotational torque acts, such as an aluminum brake drum, an aluminum die-cast hub for a motorcycle, and a journal portion of a power train including a motor.

The obtained insert casting member can be insert cast with aluminum or the like by, for example, a die casting method, to obtain an insert casting member. The conditions for the injection of aluminum and the like are not particularly limited, and for example, the injection can be carried out at an injection pressure of 50 to 100MPa and an injection speed of 1.5 to 4.0 m/sec by injecting the melt at 620 to 670 ℃ using ADC12, ADC10 and ADC 3.

The insert casting member of the present invention has a convex portion having a linear portion and a collective portion on the surface to be insert cast, and therefore, the area in contact with the metal to be insert cast can be increased more than ever, and heat transfer and heat dissipation properties can be improved efficiently. In addition, in the case where the insert casting member has the cross-sectional shape of the convex portion according to claim 1, the cast metal bites into the portion to improve the adhesion strength, and a gap is less likely to be formed between the insert casting member and the cast metal, thereby improving the thermal conductivity to the cast metal. In addition, in the case where the convex portions have, for example, an isotropic mesh structure, the convex portions exert an effect as reinforcing ribs, and can contribute to dispersion and reduction of stress generated by external force from various directions. For example, if the insert casting member is a cylinder sleeve, the specific modulus of elasticity in the radial direction or the axial direction of the inner bore can be increased, and deformation of the insert casting member can be prevented. Therefore, the cylinder sleeve can be made thin and light while maintaining the same rigidity. In the case of the shape of the convex portion according to claim 2, particularly when the molten aluminum is filled between the inner holes in die casting of the multi-cylinder block, since the height of the convex portion is different at random, there are inevitably portions where the low-height portions of the convex portion face each other, and therefore the molten aluminum can more easily pass between the convex portions and between the inner holes, and the effect of improving the filling property of the molten aluminum can be obtained. This effect is a remarkable effect as compared with the case of the prior art in which the height of the convex portion is the same. In addition, the inner hole pitch can be set narrower than in the conventional art, and the engine can be downsized.

The effect of dispersing and reducing the stress generated at the insert casting interface, which is provided in the insert casting member according to the present embodiment cast with aluminum or the like, will be described. FIGS. 18A to 18D are views for explaining an insert casting structureThe piece is a graph of the stress generated at the sleeve-in-casting interface of the cylinder block in the case of a cylinder sleeve cast in the engine block. Fig. 18A is a view schematically showing the cylinder liner 11 provided with the projections 3 on the surface thereof and the cast-in aluminum 12. Fig. 18B is an enlarged view of the X portion in fig. 18A. In the embodiment shown in fig. 18B, the unit constituted by the convex portion 3 does not have a pin-shaped individual protrusion portion or a convex bottom surface portion. Tau is₁The shear stress generated at the interface between the insert casting member and the metal such as aluminum (insert casting interface) when the cylinder head is fastened to the cylinder liner 11is shown. Sigma₁The compressive stress generated when the cylinder sleeve 11is insert-cast with aluminum 12 is shown.

Fig. 18C is a view showing an insert casting interface of a cylinder sleeve having a surface structure according to embodiment 1 of the present invention as another cylinder sleeve cast into an engine block similar to that shown in fig. 18A. In the embodiment shown in fig. 18C, the unit constituted by the convex portion 3 includes a taper pin-shaped individual protrusion 5a and a half-dome-shaped individual protrusion 5 b. Tau is₂Is the shear stress that occurs at the cast-in interface when the cylinder head is fastened to the cylinder liner 11. If the shear stress tau is to be applied₂The value of (d) and the shear stress τ of FIG. 18B₁Is compared to give a value of τ₂＜τ₁The presence of the individual protrusions can reduce the shear stress generated at the cast-in interface.

Fig. 18D is a view showing an insert casting interface of a cylinder sleeve having a surface structure according to embodiment 2 of the present invention as another cylinder sleeve cast into an engine block similar to that shown in fig. 18A. In the embodiment shown in fig. 18D, in the unit constituted by the convex portion 3, the bottom surface portion has a convex structure bulging toward the outer circumferential surface side of the cylinder liner. Sigma₂The compressive stress generated when the cylinder sleeve 11is insert-cast with aluminum 12 is shown. If the compressive stress sigma is to be reduced₂The value of (d) and the compressive stress σ of FIG. 18B₁Is compared to obtain a value of₂＜σ₁The convex bottom surface can reduce the compressive stress.

In this way, in the engine block, by using the insert casting member having the pin-shaped individual projections according to the embodiment of the present invention, the projections serve as barriers against the shear load and the compression load acting on the insert casting interface, and the shear stress generated in the insert casting interface region can be dispersed and reduced. This reduces the amount of deformation of the cast-in member, and suppresses the deformation. Further, by using the insert casting member having the bottom surface portion with the convex structure, the rigidity of the surface of the unit bottom surface portion is improved, and therefore, the rigidity of the entire insert casting member is also increased, and if the sleeve is used, the effect of suppressing the deformation of the inner hole is obtained, and the sleeve can be further thinned. Further, since the vibration damping property is improved, the quietness can be ensured.

Next, fig. 19A to 19D are diagrams illustrating stress generated at a sleeve insert-casting interface in the case where the insert-casting member is a sleeve that is a sliding member that contacts a brake shoe cast in a drum brake. Fig. 19A is a sectional view schematically showing the sleeve 11 having the convex portion 3 on the surface thereof, the cast aluminum 12, and the brake shoe 14 located inside thereof. In fig. 19A, N represents the braking load, and r represents the rotation direction of the wheel. Fig. 19B is an enlarged view of a portion Y in fig. 19A. In the embodiment shown in fig. 19B, the unit constituted by the convex portion 3 does not have a pin-shaped individual protrusion portion or a convex bottom surface portion. Tau is₁The shear stress generated in the insert-cast interface of the sleeve 11 when the braking load N acts on the drum brake rotating in the r direction is shown. Sigma₁The compressive stress generated when the sleeve 11is insert-cast with aluminum 12 is shown. The arrow denoted by O indicates the direction of the outer peripheral surface of the sleeve 11, and the arrow denoted by t indicates the direction of the rotational torque.

Fig. 19C is a view showing an insert-casting interface of a sleeve having a surface structure according to embodiment 1 of the present invention, which is another sleeve cast into a drum brake similar to that shown in fig. 19A. In the embodiment shown in fig. 19C, the unit constituted by the convex portion 3 includes tapered pin-shaped individual protrusions 5a and semi-dome-shaped individual protrusions 5 b. Tau is₂When a braking load N acts on a drum brake rotating in the r direction, shear stress is generated at the cast-in interface of the sleeve 11. If the shear stress tau is to be applied₂The value of (d) and the shear stress τ of FIG. 19B₁Is compared to give a value of τ₂＜τ₁Due to individual protrusionsThe presence of the portion can reduce the shear stress generated at the cast-in interface.

Fig. 19D is a view showing an insert-casting interface of a sleeve having a surface structure according to embodiment 2 of the present invention, which is a sleeve cast in a drum brake similar to that shown in fig. 19A. In the embodiment shown in fig. 19D, in the unit constituted by the convex portions 3, the bottom surface portion has a convex structure bulging toward the outer circumferential surface side of the sleeve. Sigma₂The compressive stress generated when the sleeve 11is insert-cast with aluminum 12 is shown. If the compressive stress sigma is to be reduced₂Will be the same as the compressive stress σ of fig. 19B₁Is compared to obtain a value of₂＜σ₁Since the compressive stress can be reduced by the convex bottom surface portion, local deformation of the sleeve is suppressed, and the μ value (friction coefficient) can be stabilized to suppress brake noise.

As described above, by using the insert casting member according to the embodiment of the present invention in the drum brake, in addition to the effects described with reference to fig. 18A to 18D, there are also effects of suppressing vibration of the rotating insert casting member, stabilizing the friction coefficient, and stabilizing the braking characteristics.

[ examples ]

The present invention will be described in more detail below with reference to examples. However, the following examples do not limit the present invention.

The casting-in members according to embodiment 1 and embodiment 2 of the present invention are manufactured by the manufacturing method shown in embodiment 3. In examples 1 and 2, the insert casting member according to embodiment 1 was manufactured, and in examples 3 and 4, the insert casting member according to embodiment 2 was manufactured. The production conditions are shown in table 1.

[ Table 1]

	Mold temperature/. degree.C	Thickness of coating layer/mm	The proportion/mass percent of bentonite is%
				Example 1	155	1	10
Example 2	160	1	10
				Example 3	135	1.5	11
Example 4	130	2	9.5

Fig. 11 shows an electron micrograph of the insert casting member obtained in example 1. In addition to the mesh-like convex portions 3, it can be visually recognized that the taper pin-like individual protrusions 5a are formed in the cell. Fig. 20 shows an electron micrograph of the insert casting member obtained in example 2. The scale in the figure represents 500 μm. The individual protrusions 5b having the dome shape formed in the cell can be visually recognized. All arrows indicate individual protrusions having a half-dome shape.

Fig. 14 shows an electron micrograph of the insert casting member obtained in example 3. In fig. 14, it can be visually recognized that the bottom surface portion C is a convex surface bulging in the outer circumferential direction of the surface to be insert-cast. Fig. 21 is an electron micrograph showing a cross section of the insert casting member obtained in example 4. The scale in the figure represents 500 μm. In fig. 21, the bottom surface portion C is clearly visually recognized as a convex surface from the sectional view.

By evaluating the characteristics of the insert casting members of examples 1 to 4, the same effects as those described with reference to fig. 18A to 18D, that is, the effects of dispersing and reducing the shear stress generated in the insert casting interface region, were confirmed. In addition, the rigidity of the entire insert casting member is increased, and deformation of the inner bore is suppressed.

Industrial applicability of the invention

The insert casting member of the present invention is suitably used for a cylinder sleeve for a cylinder block (C/B) insert cast by aluminum die casting, a sliding member for an aluminum dynamic drum, a bearing member for a motor, a lower crankcase, a transmission case, a hub of a two-wheeled vehicle, and the like, all of which require NVH characteristics such as vibration damping performance.

Claims

1. An insert casting member having a mesh-like convex portion, a bottom surface portion surrounded by the convex portion, and a single protrusion portion on a surface to be insert cast, the insert casting member being characterized in that,

at least a part of the bottom surface portion is a substantially flat surface,

the pin-shaped protrusion part is

(b) A semi-dome-shaped protrusion part with a height less than 2 times of the diameter of the root part and a curved surface at the top end,

2. An insert casting member having a mesh-like convex portion on an insert casting surface and a bottom surface portion surrounded by the convex portion,

a unit comprising at least a part of a mesh-like convex portion and a bottom portion surrounded by the convex portion, the bottom portion of the unit being a convex surface rising from a root portion of the convex portion and bulging in an outer circumferential direction of the surface to be insert-cast,

3. An insert casting member having a mesh-like convex portion, a bottom surface portion surrounded by the convex portion, and a single protrusion portion on a surface to be insert cast, the insert casting member being characterized in that,

at least a part of the bottom surface portion is a substantially flat surface,

the pin-shaped protrusion part is

4. An insert casting member having a mesh-like convex portion on an insert casting surface and a bottom surface portion surrounded by the convex portion,

5. The insert casting member according to claim 2 or 4,

the bottom surface portion of the convex surface of the unit includes a pin-shaped individual protrusion portion rising from the bottom surface portion.

6. The insert casting member according to claim 5,

the pin-shaped protrusion part is

(b) A semi-top-shaped protrusion part with a height less than 2 times of the diameter of the root part and a curved surface at the top end.

7. A method for manufacturing an insert casting member according to claim 1, comprising at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

the recess is pin-shaped and does not reach the surface of the mold.

8. A method for manufacturing an insert casting member according to claim 2, comprising at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

9. A method for manufacturing an insert casting member according to claim 3, comprising at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

the recessed portion is pin-shaped and does not reach the surface of the mold.

10. A method for manufacturing an insert casting member according to claim 4, comprising at least the steps of:

applying a coating agent to a surface of a mold into which a melt flows;

the cracks are formed by a plurality of gaps extending from the surface of the coating layer to the surface of the mold, the width of the gaps is formed to be narrower as the gaps extend from the surface of the coating layer to the surface of the mold, and the depths of the gaps are uneven,