JP3663867B2 - Casting casting method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for cast-casting insert members of dissimilar metal parts such as steel on light metal castings such as pulleys and pistons.
[0002]
[Prior art]
In the manufacture of lightweight crank pulleys attached to engines such as automobiles, the body part is cast with a light metal material such as aluminum or aluminum alloy in order to promote weight reduction. It is made of an insert member (casting material) of an iron-based metal member with excellent wear resistance, and this insert member is held in a predetermined position in the mold and cast with a molten metal made of a light metal material such as aluminum. Integrated casting.
[0003]
The cast-in casting process will be briefly explained. For example, even if an insert member made of polished steel is cast as it is, it has poor bondability with light metal materials and is easily separated. Process.
As a pretreatment of this aluminized treatment, the insert member is immersed in a degreasing solution such as alkaline degreasing or acetone soaking the insert member in a degreasing solution containing sodium hydroxide or the like as a main component, and subjected to a solvent degreasing treatment. Is immersed in a molten aluminum melted at around 730 ° C. for a predetermined time to be aluminized.
[0004]
Next, casting is performed. Molding is performed with casting sand, the mold is preheated with a gas burner and dried, and then die assembly is performed. The insert member that has been aluminized during the mold assembly is placed at a predetermined position in the mold. Then, a molten metal such as molten aluminum at around 740 ° C. is poured into the finished mold assembly, and after cooling and mold breaking, the molded product is taken out to complete cast-off casting.
[0005]
As an example of this mold assembly, a lightweight crank pulley mold assembly used for an automobile engine or the like is shown in FIG. First, the first mold member 12 is placed on a base plate (not shown), and then the small rings 40 and 40 and the large ring 50 that are insert members are sandwiched from both sides by two half-cracked second mold members 13a and 13b. Then, the second mold members 13a and 13b are positioned by a dama 14a and placed on the first mold member 12. Further, a third mold material 15 coated with zircon sand 16 is positioned and placed by the dams 14b and 14c on the portion that contacts the inside of the lightweight crank pulley 1 to constitute a mold. In this mold assembly, the portion indicated by the arrow X is the feeder position. In order to control the local cooling rate of the molten metal, the cold gold 18 is appropriately arranged.
[0006]
In the prior art, when performing fill-up casting in the above-described process, ring-shaped, disk-shaped, or cylindrical insert members 40, 50 having grooves 3 in the circumferential direction of the outer peripheral portion are arranged in the mold. However, as shown in FIG. 5, the tip portion of the mold 13a has a round cross section in the groove portion 3 of the insert member 40, 50, that is, on the inclined surface 42, 42 or 52, 52 of the groove portion 3. The insert members 41 and 42 are positioned and supported by contact.
[0007]
The support on the inclined surfaces 42, 42 or 52, 52 of the groove portion 3 is performed because the aluminum base material 2 is cast outside the groove portion 3, so that there is no other appropriate support portion.
[0008]
[Problems to be solved by the invention]
However, when aluminum alloy is used for the cast material, that is, the base material 2, in order to improve the bonding strength between the insert members 40, 40, 50 and the base material 2, the insert members 40, 40, 50 are previously aluminized. Since the treatment is performed, since the aluminum used for the aluminized treatment is at a high temperature, the groove portion 3 of the insert member 40, 40, 50 is thermally deformed by heat, and the inclination angle of the groove portion 3 is shifted. In particular, since the inclined surfaces 42, 42 or 52, 52 on both sides forming the groove 3 are press-molded, the residual stress is released when heat is applied, so that it is unstable and thermally deformed. easy.
[0009]
For this purpose, if the inclined surface 42, 42 or 52, 52 of the groove portion 3 of the deformed insert member 40, 40, 50 is brought into contact with and supported by the tip of the round section of the support portion 5, it is point contact in a sectional view. Therefore, if the other part, that is, the inclined surface 42, 42 or 52, 52, has an inclination angle enlarged or reduced by thermal deformation, a positioning error between the insert members 40, 40, 50 and the mold 13a becomes large. Therefore, accurate positioning cannot be performed. As a result, as shown in FIG. 6, there is a problem that the insert member 50 sags A, the shafts of the insert members 40 and 40 are decentered B and B ', and an axial deviation D occurs.
[0010]
In particular, when casting a plurality of insert members 40, 40, eccentricity and axial misalignment are likely to occur between the insert members 40, 40, and this correction complicates the mold assembly process. Therefore, the temperature distribution of the insert member becomes uneven during casting, resulting in unevenness, and the temperature control becomes difficult, so the quality of the cast product is deteriorated, resulting in an increase in defective products and poor product yield. There is a problem that the product cannot be supplied.
[0011]
Further, in order to make it easier to place the insert member in the mold, it is necessary to provide a clearance as a fitting allowance between the insert member and the mold. However, the change in the angle of the groove due to the thermal deformation in the aluminizing process of the groove described above is previously determined. Considering this, if this clearance is increased, there is a problem that the insert member is tilted, decentered, or misaligned in the axial direction.
[0012]
In addition, if the arrangement of the insert member is shifted, it becomes difficult to achieve a balance around the rotation axis, and there is a problem that normal operation cannot be performed due to uneven rotation and damage to the rotation axis when used at a high rotation speed. .
In addition, in order to avoid these problems, if the insert member is made thick to prevent thermal deformation of the insert member, there is a problem that the weight of the product increases.
[0013]
The present invention has been made in order to solve the above-described problems, and its purpose is to improve the positioning accuracy of the casting position of the insert member, cast a product with high accuracy, and simplify the positioning work. An object of the present invention is to provide a cast-in-place casting method that can improve the efficiency of mold assembly work.
[0014]
[Means for Solving the Problems]
The cast-in casting method for achieving the above object casts an insert member having a substantially rotating body shape such as a ring shape, a disk shape, or a cylindrical shape in which a groove portion is formed along the circumferential direction of the outer peripheral portion. In the casting method, the members forming both sides of the opening of the groove are extended in the outer diameter direction to form a pair of annular protrusions, and the protrusions are engaged with the outer surface in the mold. A fixed mold part is formed by projecting, the fixed part is fitted and clamped to the projecting part of the insert member, the insert member is arranged at a predetermined position in the mold, and the entire mold is assembled and assembled. This is a casting method in which molten metal is poured into the casting.
[0015]
And the said protrusion part of the said cast-up product is deleted by cutting after cast casting.
In the casting method in which the insert member is cast, an annular protrusion is formed which is easy to hold on the insert member and is not easily deformed by heat and can maintain good positioning accuracy, and this protrusion is used as a fixed portion in the mold. Since the insert member is positioned at a predetermined position in the mold by being fitted and supported, the positioning can be performed accurately and the operation can be simplified, so that the work efficiency is improved.
[0016]
That is, since this insert member is press-molded, residual stress remains in the groove after press molding, and since this residual stress is released when heat is applied during aluminizing treatment or pouring, etc., It is easy to be thermally deformed, and the inclination angle of the groove is easily changed by this heat deformation. On the other hand, the projecting portion formed in an annular flat shape does not generate this residual stress, and the amount of thermal deformation in the thickness direction is small. Therefore, if the projecting portion is held on the annular flat surface of the projecting portion, positioning can be performed with high accuracy.
[0017]
In particular, this casting method is particularly effective in the case where the groove portion of the insert member has a V-shaped cross section and the portion held by the mold has only an inclined portion.
Further, when casting a plurality of the insert members, the side surfaces of the projecting portions are joined and integrated, and then the fixing portion is fitted and clamped to the projecting portions of the insert member. When the insert member is arranged at a predetermined position and the entire mold is assembled and cast, the trouble of positioning the insert member individually can be saved, so that the process of attaching the insert member to the mold is simplified.
[0018]
In addition, the integration of the insert members eliminates the occurrence of eccentricity and displacement between the insert members, so that the insert members can be accurately placed in the mold.
This cast-in casting method can also be used when the molten metal is aluminum or when a molten metal other than aluminum, such as magnesium, zinc, or an alloy thereof is used as a cast-in material (base material). Further, it can be applied to casting by a sand mold or a mold or die casting.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In the following, a cast ball casting method according to the present invention will be described with reference to the drawings, taking as an example a lightweight crank pulley in which a casting is used in an automobile engine or the like.
The molded product of this lightweight crank pulley 1 is as shown in FIG. 2, and the groove portion 3 where the belt abuts is formed by insert members 40, 40, 50 made only of SPCC material and steel. Yes. As shown in FIG. 3, these insert members 40 and 50 have a ring-like substantially rotating body shape, and a cross section of the groove portion 3 has a V shape.
[0020]
In the case of the insert member 40 which is a small ring, the two ring members 41a and 41b or 41c and 41d are joined back to back at the welded portion 46, and each set has a cross-section V-shaped groove 3 Is formed along the circumferential direction of the outer peripheral portion.
On the outer periphery of the insert member 40, members forming both side surfaces of the opening of the groove portion 3, that is, side surface portions 43, 43 are extended in the outer diameter direction to form a pair of annular projecting portions 44, 44. That is, the pair of annular projecting portions 44, 44 are formed so as to project from the surface perpendicular to the rotation axis C1 of the insert member 40.
[0021]
Further, the adjacent ring members 41b and 41c of the two insert members 40, 40 are joined and integrated by the welded portion 45 in the protruding portion 44 to form an insert member 4 having two V-shaped grooves 3. .
Similarly, in the large ring insert member 50, as shown in FIGS. 1 and 2, two ring members 51a and 51b are joined by a welded portion 56, and a pair of V-shaped groove portions 3 are formed on the outer peripheral portion. Forming. Similarly to the insert member 40 of the small ring, members that form both side surfaces of the opening of the groove 3 on the outer periphery of the insert member 50, that is, side surfaces 53, 53 are extended in the outer diameter direction to form an annular 1 Protrusions 54, 54 having a pair of flat surfaces are provided.
[0022]
Here, the two ring-shaped members 51a and 51b are joined by welding to form one insert member 50. However, an insert member 50 integrally formed by casting or the like from the beginning may be used.
And even if these insert members 4 and 50 are cast as they are, the bondability with the light metal material which is the base material 2 is poor and easy to separate, so an aluminized process is performed to improve the bondability.
[0023]
As this pretreatment, the insert members 4 and 50 are immersed in a degreasing solution containing sodium hydroxide or the like as the main component, alkali degreasing is performed, then the substrate is washed with water, and further immersed in a degreasing solution such as acetone for solvent degreasing treatment. Then, after removing this degreasing liquid by wiping or the like, it is dried at about 100 ° C. so that the insert members 4 and 50 are not oxidized.
Then, the surface-treated insert members 4 and 50 are aluminized so as to become familiar with the aluminum base material when an aluminum alloy casting is made. In this treatment, the insert members 4 and 50 are supported by a support member 730. A reaction layer having a predetermined thickness is formed by immersing in a molten aluminum melted at about 0 ° C. for a predetermined time, and then the excess molten aluminum is removed.
[0024]
Next, the casting process is started. At the time of casting, in order to fit and hold the above-described insert members 4 and 50, the ring-shaped fixing portion 7 that engages the protruding portion 44 with the outer surface in the molds 13a and 13b. Protrusively provided.
When the molds 12, 13a, 13b, 15 are assembled as shown in FIG. 4, the fixing part 7 is inserted into the projecting parts 44, 54, so that the insert members 4, 50 are semicircular. The entire molds 12, 13a, 13b, 15 are assembled by sandwiching them between the two divided molds 13a, 13b and arranging them at predetermined positions.
[0025]
After this mold assembly, molten aluminum is poured and cast, and after this casting, cooling and mold dispersion are performed to take out the cast-in-place molded product. Since the protrusions 44 and 54 of the insert members 4 and 50 are extra, the cast-in-molded product is set in a cutting machine and deleted by cutting to obtain a finished product.
This cutting process not only cuts off the protruding portions 44 and 54 of the insert members 4 and 50, but also cuts to the E line and F line of FIG. 2, and further, part of the groove 3 of the insert members 4 and 50 is cut. Cut and shape by this cutting.
[0026]
According to this cast-in casting method, in the casting method in which insert members 40 and 50 such as steel materials are cast, protrusions 44 and 54 are provided at positions that are easy to position and hold, and the mold is formed by the protrusions 44 and 54. Since the inner fixing portion 7 is fitted and held, positioning can be performed accurately and positioning accuracy can be increased. Further, since the positioning and fixing can be performed only by fitting the protruding portions 44 and 54 to the fixing portion 7 in the mold, the positioning operation can be simplified and the working efficiency can be improved.
[0027]
The reason why the positioning accuracy is improved will be described in detail as follows.
Since the ring members 41a, 41b, 41c, 41d, 51a, 51b of the insert members 40, 50 are press-molded, residual stress remains in the groove portion 3 after press molding. When heat is applied, such as during hot water, it is released and thermally deformed.
[0028]
Although the inclination angles of the inclined surfaces 42 and 42, 52 and 52 forming the groove 3 change due to this thermal deformation, the annular protrusions 44 and 54 do not generate this residual stress and the amount of thermal deformation in the thickness direction Since it is small, if it is held on the annular flat surface of the projecting portions 44, 54, positioning can be performed with high accuracy.
In this mold assembly, the insert members 4 and 50 are fixed not by the inclined surfaces 42 and 52 in the groove 3 but by the projecting portions 44 and 54 which are flat surfaces perpendicular to the rotation axis C1 of the insert members 4 and 50. The part 7 is sandwiched and supported. That is, since it is positioned by engaging with the fixed portion 7 having a surface perpendicular to the central axis C of the mold assembly, the insert members 4 and 50 can be supported by the engagement of the planes perpendicular to this axis. , Positioning accuracy can be increased.
[0029]
Further, when casting a plurality of insert members 40, 40, the side surfaces of the projections 44, 44 are joined together by the welded portion 45, and then the welded projections 44, 44 and other welds are joined. Since the insert member 4 is held in a predetermined position by fitting and holding the mold fixing portion 7 between the portions 44 and 44, the mounting work of the insert members 40 and 40 to the molds 13a and 13b can be simplified. At the same time, the eccentricity and misalignment between the insert members 40 and 40 can be prevented.
[0030]
【The invention's effect】
As described above, according to the cast-in casting method according to the present invention, in the casting method in which an insert member having a substantially rotating body such as a steel material and having a groove portion is cast, the opening portion of the groove portion is formed in the insert member. A pair of annular projections are formed to extend by extending both side portions of the mold, and a fixed portion formed in the mold is fitted and clamped by this projection to position the insert member at a predetermined position in the mold. Therefore, positioning can be performed accurately. Further, since positioning and fixing can be performed simply by inserting the fixing portion in the mold between the protruding portions, the mold assembling work can be simplified and the working efficiency can be improved.
[0031]
Further, this cast-in casting method is particularly effective when the groove portion has a V-shaped cross section and the portion held by the mold has only an inclined portion that is easily thermally deformed.
Further, when casting a plurality of insert members, the side surfaces of the protruding portions are joined and integrated, and then the fixing portion is fitted and clamped to the protruding portion of the insert member, and the insert member is placed at a predetermined position in the mold. Since the entire mold is assembled and cast, the process of attaching the insert member to the mold can be simplified, and at the same time, eccentricity and displacement between the insert members can be prevented.
[0032]
Accordingly, the insert member can be accurately positioned during the cast-in casting, and the mold assembling operation can be simplified, so that it is possible to manufacture a light and inexpensive aluminum casting product.
[Brief description of the drawings]
FIG. 1 is a partial sectional view of a mold showing a method for holding an insert member according to the present invention.
FIG. 2 is a front view of a lightweight crank pulley with a partial cross-sectional view.
FIGS. 3A and 3B are diagrams showing an insert member of a lightweight crank pulley, where FIG. 3A is a front view and FIG. 3B is a side view of a partial cross-sectional view.
FIG. 4 is a sectional view of a mold configuration showing an example of cast-in casting.
FIG. 5 is a partial cross-sectional view of a mold showing a conventional method for holding an insert member.
FIG. 6 is a partial cross-sectional view of a mold for explaining a defect in a conventional method for holding an insert member.
[Explanation of symbols]
1 Lightweight crank pulley (casting) 2 Molten metal (casting base material)
3 Groove 4 Integrated small ring 5 Support 7 Fixed
12 1st mold material 13a, 13b 2nd mold material
14a, 14b, 14c Dama 15 3rd mold
16 Zircon sand 18 Cold gold
40 Small ring (insert member) 41a, 41b, 41c, 41d Ring member
42 Inclined surface 43 Side surface
44 Protrusion 45, 46 Weld
50 Large ring (insert member) 51a, 51b Ring-shaped member
52 Inclined surface 53 Side
54 Protruding part 55, 56 Welded part

Claims (3)

In a method for casting by casting an insert member having a substantially rotating body shape such as a ring shape, a disk shape, or a cylindrical shape, in which a groove portion is formed along the circumferential direction of the outer peripheral portion, both side surfaces of the opening portion of the groove portion are formed. And extending a member in the outer diameter direction to form a pair of annular projecting portions, and forming a fixed portion for engaging the projecting portion with an outer surface in the mold so as to project the projecting portion of the insert member. The cast part casting method in which the fixed part is fitted and clamped, the insert member is arranged at a predetermined position in the mold, the entire mold is assembled, and molten metal is poured into the assembled mold and cast. The cast-in-place casting method according to claim 1, wherein the groove has a V-shaped cross section. When casting a plurality of the insert members, the side surfaces of the projecting portions are joined and integrated, and then the fixing portion is fitted and clamped to the projecting portions of the insert member, so that a predetermined inside of the mold is obtained. The cast-in casting method according to claim 1, wherein the insert member is disposed at a position and the entire mold is assembled and cast.

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