JP2005088017A - Composite sleeve for die casting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance erosion resistance and wear resistance of a sleeve for a die cast machine and obtain an improved service life of the sleeve, by applying ceramics to the sleeve. <P>SOLUTION: The sleeve has a front cylindrical body (10) and a rear cylindrical body (20) connected to the rear end side of the front cylindrical body. The rear cylindrical body (20) is an overlapped cylindrical body consisting of a ceramic inner cylinder (21) and a metallic outer cylinder (22) surrounding the ceramic inner cylinder (21). The overlapped boundary face between the ceramic inner cylinder (21) and the metallic outer cylinder (22) has a circumferential gap (23) (a gap width of 0.5-1 mm). The front cylindrical body (10) and the rear cylindrical body (20) are connected in such a manner that an annular projection (10p) and an annular projection (22p) are fitted. The ceramic inner cylinder (21) is sandwiched between the front cylindrical body (10) and a stop plate (30) so as to be clamped and held in an axial direction. A ring-shaped spacer (25) comprising a low thermal expansive material and having a L-shaped cross section, if desired, is interposed between a flange (21a) of the ceramic inner cylinder and a diameter-enlarged step (22b) of the metallic outer cylinder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in a plunger sleeve constituting a die casting machine which is an injection casting apparatus for non-ferrous metals such as aluminum alloys.

  As shown in FIG. 4, the sleeve (1) installed in the die casting machine is a cylindrical body having a hot water supply port (26) for pouring molten metal (M) on the rear end side, and a plunger is provided in the hollow hole. The chip (2) is driven back and forth. The sleeve (1) communicates with the die (41) of the die casting machine body (4) and is installed so that the rear end side having the hot water supply port (26) protrudes outside the platen (die plate) (42). . The molten metal (M) supplied from the hot water supply port (26) into the sleeve (1) is injected (pressure injection) into the mold (41) through the plunger tip (2).

The inner peripheral surface of the sleeve (1) requires melt resistance against molten metal and wear resistance against reciprocating sliding of the plunger tip (2). When the inner surface of the sleeve (1) is damaged by melting or abrasion, molten metal is inserted into the sliding contact interface between the sleeve (1) and the plunger tip (2), increasing the sliding resistance, and the die (41 ), The casting speed is lowered, the smoothness of the casting operation is impaired, and the product quality is lowered. Conventionally, a cylinder made of hot tool steel (JIS-G4404) represented by SKD61 has been used as the sleeve (1). The sleeve (1) has relatively good erosion resistance, wear resistance, etc. against non-ferrous metal melts, but as an improved measure to further improve the erosion resistance, etc., erosion resistance, wear resistance, etc. As shown in FIG. 5, it is known that a ceramic cylinder (51) is shrink-fitted inside a metal (SKD61 tool steel, etc.) cylinder (52) to form a laminated structure.
Japanese Patent No. 3093558

The above-mentioned laminated sleeve (shrink fit structure) has the following problems when used in actual equipment.
The thermal expansion coefficient (for example, SKD61 tool steel: about 12 × 10 ⁻⁶ / ° C.) of the metal cylinder (52) is the thermal expansion coefficient of the ceramic inner cylinder (51) (for example, silicon nitride ceramics: about 1.5-3 × 10 ^−6). Therefore, the shrink-fit effect is reduced as the heating temperature rises due to contact with the molten metal, and the laminated structure becomes unstable. Further, the sleeve (1), as the influence of heat from the molten metal, the warpage D ₁ and axis direction shown in chain line in FIG. 7, is liable to occur deformation D ₂ of the radial cross-section shown in chain line in Figure 8. In these deformations, since the molten metal (M) in the sleeve (1) is stored as shown in FIG. 6, there is a temperature difference between the upper part and the lower part of the sleeve (1), and the upper part. And the lower side portion have different cross-sectional shapes (a hot water supply port 26 is open on the upper side portion).

The above deformation (D ₁ ,
The size of D ₂ ) varies depending on the shape and size of the sleeve, the hot water supply temperature, and the like, but the amount of deformation of the normal warpage deformation D ₁ (FIG. 7) (= axial deviation / axial length) is about 0.5 to The deformation amount (= minor axis / major axis) of 1 mm / 300 mm and radial deformation D ₂ (FIG. 8) usually reaches about 0.2 to 0.5 mm (when the sleeve diameter is 150 mm). This deformation of the sleeve prevents smooth reciprocation of the plunger tip (2) and promotes wear damage of the sleeve and the plunger tip. In particular, in the sleeve (1) having the laminated structure (shrink-fit structure) shown in FIG. 5, cracks and defects of the ceramic inner cylinder (51) are induced with the deformation of the metal outer cylinder (52), and the laminated structure is changed. The effect of adoption will be impaired.
The present invention has been made for the purpose of solving the above-described problems relating to a sleeve for a die casting machine having a ceramic-metal laminated structure, effectively exhibiting the functions of ceramics, and improving the durability and stability of casting operation. It is.

The composite sleeve for the die casting machine of the present invention is
The front cylinder (10) and the rear cylinder (20) having a hot water supply port (26) connected to the rear end thereof with the axial center aligned, and attached to the tail end of the rear cylinder (20) It consists of a ring-shaped stop plate (30), the front cylinder (10) is a single-layer cylinder made of metal, and the rear cylinder (20) surrounds an inner cylinder (21) made of ceramics. A polymer cylinder with an outer cylinder (22) made of metal, and has a circumferential gap (23) between the inner cylinder (21) made of ceramic and the outer cylinder (22) made of metal, The inner cylinder (21) is characterized in that it is sandwiched and held in the axial direction between the rear end face of the front cylinder (10) and the ring-shaped stopper plate (30).

  According to the present invention, an inner cylinder (21) made of ceramic is sandwiched and held in the axial direction by being sandwiched between a front cylinder (10) and a ring-shaped stopper plate (30), and an inner cylinder made of ceramic ( 21) and a metal outer cylinder (22) are provided with a circumferential gap (23). For this reason, unlike the shrink-fit structure of the conventional “ceramics-metal” laminated sleeve (FIG. 5), the outer cylinder (22) and the inner cylinder ( 21), which is caused by a difference in thermal expansion from that of 21) (the holding state of the ceramic inner cylinder is unstable due to a decrease in the shrink-fit effect), and the metal outer cylinder (22) is thermally deformed (axial direction in FIG. 7). Even if warpage deformation or radial deformation in FIG. 8 occurs, the deformation of the outer cylinder (22) directly acts on the ceramic inner cylinder (21) by interposing the circumferential gap (23). The ceramic inner cylinder (21) is maintained in a healthy form without cracks or chips.

  Damage to the inner peripheral surface caused by the use of a die casting machine sleeve, such as erosion and wear, is a phenomenon that is observed in the vicinity of the hot water inlet (26), and this is the reason that affects the useful life of the sleeve. The progress of damage in the vicinity. Therefore, when applying ceramics, it is not always necessary to apply this to the entire length of the sleeve (1). If it is applied only to the rear side (rear cylinder 20) having the hot water supply port (26), it will be described later. While ensuring sufficient strength and robustness required for the sleeve (1), it is possible to obtain a dramatic improvement in the service life due to the application of ceramics.

Embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a sectional view of an essential part in the axial direction showing an embodiment of the composite sleeve of the present invention, and FIG. 2 shows a section taken along the line II. The composite sleeve (1) includes a front cylinder (10) and a rear cylinder (20) having a hot water supply port (26), and both are connected with their axes aligned. The rear cylinder (20) is a polymer cylinder of an inner cylinder (21) made of ceramics and an outer cylinder (22) made of metal surrounding its outer peripheral surface, and the ceramic inner cylinder (21) and the metal outer cylinder. A circumferential gap (23) is provided between (22) and (22).

The ceramic inner cylinder (21) of the rear cylinder (20) has a flange (21a) at the front end, and the metal outer cylinder (22) is formed in a circumferential direction for engaging the flange (21a). The enlarged diameter step (22b) is provided. When the flange (21a) of the ceramic inner cylinder (21) is engaged with the diameter-expansion step (22b) of the metal outer cylinder (22), both are concentrically polymerized. The metal outer cylinder (22) on its front edge, is provided an annular protrusion toward the front tubular member (10) (22 _P), after the front cylinder (10) in response thereto At the edge, an annular protrusion (10 _P ) facing the rear cylinder (20) is formed.

The outer cylinder (22) of the front cylinder (10) and the rear cylinder (20) are coaxially connected by fitting the annular projections (10 _P ) and (22 _P ). As the connection form, for example, an external screw (not shown) is provided on the annular protrusion (10 _P ), and an internal screw (not shown) is provided on the annular protrusion (22 _P ), and the two are screwed together. If so, the front end face of the ceramic inner cylinder (21) is pressed against the end face of the annular protrusion (10 _P ) of the front cylinder (10) by tightening the screws. In the figure, regarding the connection structure between the front cylinder (10) and the outer cylinder (22) of the rear cylinder, the annular protrusion (10 _P ) of the front cylinder (10) is replaced with the outer cylinder (22). The annular protrusion (22 _P ) is inserted inside the annular protrusion (22 _P ), but the fitting of the annular protrusions (10 _P ) and (22 _P ) is opposite to that shown in the figure. It is good also as the connection structure made into.

A stop plate (30) is applied to the tail end surface of the rear cylinder (20). The stop plate (30) is a ring-shaped member formed of hot tool steel (for example, SKD61), and is pressed and fixed to the end surface of the metal outer cylinder (22) by bolts (31) at a plurality of positions on the peripheral edge. . Thus, the ceramic inner cylinder (21) is sandwiched between the end surface of the annular projecting portion (10 _P ) of the front cylinder (10) and the plate surface of the stop plate (30) and is held in the axial direction. Is done. Thus, the assembly of the sleeve (1) is completed by connecting the front cylinder (10) and the rear cylinder (20) and attaching the stopper plate (30). The plunger tip (2) (FIG. 4) is inserted into the sleeve (1) through the opening of the ring-shaped stopper plate (30).

  FIG. 3 shows another embodiment of the composite sleeve of the present invention. The difference from the composite sleeve of FIG. 1 is that, in the rear cylinder (20), a low heat is generated between the flange (21a) of the ceramic inner cylinder (21) and the enlarged step (22b) of the metal outer cylinder (22). A spacer (25) made of an expandable material is interposed. The spacer (25) has a ring shape with an L-shaped cross section corresponding to the step shape of the diameter-enlarging step (22b). The low thermal expansibility of the spacer (25) means that it has a lower thermal expansion coefficient than the metal outer cylinder (22). By interposing the spacer (25) in the diameter expansion step (22b), the difference in thermal expansion coefficient between the ceramic inner cylinder (21) and the metal outer cylinder (22) (the difference in thermal expansion coefficient between them) is reduced. As an effect, the stability of the sandwiched holding state of the ceramic inner cylinder (21) is enhanced.

The composite sleeve (1) shown in FIG. 3 may have the same configuration as that of the composite sleeve of FIG. 1 except that a ring-shaped spacer (25) is interposed. The cylinder (21) is sandwiched between the end surface of the annular projection (10 _P ) of the front cylinder (10) and the plate surface of the retaining plate (30) via the spacer (25) and is clamped in the axial direction. Is retained.

In the composite sleeve of the present invention, the metal outer cylinder (22) surrounding the ceramic inner cylinder (21) serves not only to connect the front cylinder (10) and the rear cylinder (20) but also to the ceramic inner cylinder ( 21) protects against contact with the container and prevents breakage. The thermal deformation due to conduction heat transfer from the front cylinder (10) to the metal cylinder (22) in the actual use of the sleeve (radial deformation D ₂ of the axial warp D ₁ and 8 in FIG. ₇₎ Even if it occurs, the circumferential gap (23) is provided between the ceramic inner cylinder (21) and, unlike the shrink-fit integrated structure (FIG. 5), cracks are generated in the ceramic inner cylinder (21). Such an external force is not applied, and the sound cylinder shape of the ceramic inner cylinder (21) is maintained.

  The appropriate gap width of the circumferential gap (23) provided between the ceramic inner cylinder (21) and the metal outer cylinder (22) is the material type of the metal outer cylinder (22) (the magnitude of the thermal expansion coefficient). Although it is different depending on the like, a gap width of about 0.5 to 1 mm is sufficient for a hot tool steel such as SKD61 which is a general sleeve material. The circumferential gap (23) is loaded with ceramic fibers (24) as a buffer material as desired.

Unlike the rear cylinder (20), the front cylinder (10) in the composite sleeve of the present invention is a single-layer cylinder, and its metal material type is a heat represented by a general SKD61 as a conventional sleeve material. It may be interstitial steel.
The inner cylinder (21) of the rear cylinder (20) is a fired ceramic product, and its material type is preferably silicon nitride ceramics such as silicon nitride and sialon from the viewpoint of resistance to melting and abrasion. Its coefficient of thermal expansion (room temperature to 600 ° C.) is about 1.5 × 10 ^{−6 to} 3 × 10 ⁻⁶ / ° C. The ceramic fibers (24) loaded in the circumferential gap (23) between the ceramic inner cylinder (21) and the metal outer cylinder (22) are, for example, Al ₂ O ₃ —SiO ₂ fibers.
The metal outer cylinder (22) of the rear cylinder (20) may be a hot tool steel represented by SKD61 like the front cylinder (10), and in addition to this, the coefficient of thermal expansion α is relatively low. Tungsten alloy (α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.), for example, W-3% Ni-2% Cu alloy, molybdenum alloy (α: about 5 × 10 ⁻⁶ to 6 × 10 ⁻⁶ / ° C.), for example, Mo-2% Ni alloy, titanium alloy (α: about 6 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C.), for example, Ti-40% Mo alloy, cemented carbide ( α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.), for example, WC-12% Co alloy or the like is applied.

As described above, the ring-shaped spacer (25) interposed between the flange (21a) of the ceramic inner cylinder (21) and the enlarged diameter step (22b) of the metal outer cylinder (22) has low thermal expansion. This has the effect of increasing the stability of the sandwiched state of the ceramic inner cylinder (21). The thermal expansion coefficient (α) is preferably about 1 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C. (normal temperature to 600 ° C.) in consideration of the thermal expansion coefficient of the ceramic inner cylinder (21). Such a low thermal expansion material has heat resistance and mechanical strength as a sleeve material in combination with low thermal expansion, and is appropriately selected from known materials.

Specific examples of the low thermal expansion material include tungsten alloys (α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.) such as W-3% Ni-2% Cu alloy, molybdenum alloys (α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.), for example, Mo-2% Ni alloy, titanium alloy (α: about 6 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C.), for example, Ti-40% Mo alloy, carbide An alloy (α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.), for example, a metal material such as WC-12% Co, which is a WC-based cemented carbide. In addition to the metal material, a CC composite (α: about 5 × 10 ^{−6 to} 6 × 10 ⁻⁶ / ° C.) can be applied. This is a solidified carbonaceous material formed by processing a mixture of carbon fibers and pitch infiltrated into the fiber gaps under pressure and heating, and has low heat expansion and heat resistance as a sleeve material.・ It has mechanical strength.

  The dividing position (= connection position) of the front cylinder (10) and the rear cylinder (20) constituting the composite sleeve of the present invention is the platen (die plate) of the die casting machine body (4) (FIG. 4) ( 42) in the vicinity of the outer surface (43) (which may be substantially coincident with the outer surface 43), the portion projecting outside the platen (42) is the rear cylinder (20), and the front portion (included in the die casting machine body). The part to be fixed is preferably the front cylindrical body (10). By using such a divided structure, the strength and robustness of the sleeve for the die casting machine can be ensured as follows. Improvement effects such as resistance to melting caused by applying the inner cylinder (21) can be sufficiently exhibited.

  In the pressurizing operation of the plunger tip (2) in which the molten metal supplied into the sleeve (1) is press-fitted into the mold (51), the plunger tip (2) advances forward from the hot water supply port (26). Since it is performed at the position (in the front cylinder 10), if the front cylinder (10) is a single-layer cylinder such as hot tool steel, it is sufficient to withstand the high pressure impact generated during the pressurizing operation. Strength and robustness are ensured. The impact caused by the pressurizing operation does not directly act on the rear cylinder (20) behind the plunger tip (2), so that the ceramic inner cylinder (21) can be protected from the impact. As described above, the melted and worn sleeve is a phenomenon in which the vicinity of the hot water inlet (26) becomes a problem. Therefore, the ceramic inner cylinder (21) is applied only to the rear cylinder (20), so that the useful life of the sleeve is improved. It is possible to obtain a dramatic improvement effect.

  Produced a sleeve (overall length 1000mm, hollow hole diameter 150mm) for die casting machine (clamping force 2500ton). The dividing position of the front cylinder (10) and the rear cylinder (20) is the platen outer surface position.

[Example 1 (test sleeve A)] (FIG. 1)
Front cylinder 10: Grade SKD61
Size Shaft length 700mm, wall thickness 50mm
Rear cylinder 20:
Axle length (portion between front cylinder 10 and stop plate 30) 300mm
Outer cylinder 22: Grade Tungsten alloy (W-3% Ni-2% Cu)
Thickness 10mm
Inner cylinder 21: Grade of nitrided elementary ceramics (5% MgAl ₂ O ₄ -5% ZrO ₂ —Si ₃ N ₄ )
Wall thickness 20mm

[Example 2 (test sleeve B)] (FIG. 1)
Front cylinder 10: Grade SKD61
Size Shaft length 700mm, wall thickness 50mm
Rear cylinder 20:
Axle length (portion between front cylinder 10 and stop plate 30) 300mm
Outer cylinder 22: Grade SKD61
Thickness 10mm
Inner cylinder 21: Grade of nitrided elementary ceramics (5% MgAl ₂ O ₄ -5% ZrO ₂ —Si ₃ N ₄ )
Wall thickness 20mm

[Example 3 (test sleeve C)] (FIG. 3)
Front cylinder 10: Grade SKD61
Size Shaft length 700mm, wall thickness 50mm
Rear cylinder 20:
Axle length (portion between front cylinder 10 and stop plate 30) 300mm
Outer cylinder 22: Grade SKD61
Thickness 10mm
Inner cylinder 21: Grade of nitrided elementary ceramics (5% MgAl ₂ O ₄ -5% ZrO ₂ —Si ₃ N ₄ )
Wall thickness 20mm
Spacer 25: Grade Tungsten alloy (W-3% Ni-2% Cu)
Thickness (axial direction) 20mm

[Real machine use test]
Each of the above test sleeves A to C is used for pressure casting of an aluminum alloy (JIS-H5302 ADC-12).
Hot water supply temperature: 680 ° C
Casting cycle time: 2 minutes In the actual machine use test, each of the test sleeves A to C was able to carry out stable casting of 10,000 shots or more.

  According to the present invention, it is possible to effectively suppress and prevent damage such as erosion and wear, thermal deformation, and damage caused by it in the vicinity of a hot water inlet of a sleeve for a die casting machine. As a sleeve of a die-casting machine by adopting a split (connected) structure of the front cylinder and the rear cylinder, making the front cylinder a single-layer cylinder and applying ceramics to the rear cylinder While ensuring the required strength and robustness, it ensures high melting resistance and wear resistance with ceramics, dramatically improves the service life of the sleeve, increases the efficiency of pressure casting operations, reduces maintenance, and casting quality It is possible to obtain an effect such as improvement and stabilization.

It is an axial direction principal part sectional drawing which shows the Example of the composite sleeve of this invention. It is the II sectional view taken on the line of FIG. It is principal part sectional drawing of the axial direction which shows the other Example of the composite sleeve of this invention.

It is principal part cross-sectional explanatory drawing of a die-casting machine main body. It is an axial sectional view showing a conventional metal-ceramic laminate sleeve. It is sectional explanatory drawing which shows the storage state of the molten metal supplied in a sleeve. It is a cross-sectional explanatory view schematically showing thermal deformation (axial warping deformation) of a sleeve. It is a cross-sectional explanatory view schematically showing thermal deformation (radial deformation) of a sleeve.

Explanation of symbols

1: Sleeve 2: Plunger tip 10: Front cylinder _10P : Annular protrusion 20: Rear cylinder 21: Ceramic inner cylinder 21a: Flange 22: Metal outer cylinder 22b: Expanded diameter step (circumferential direction)
22 _P annular protrusion 23: Circumferential gap 24: Ceramic fiber 25: Ring spacer 26: Hot water inlet

30: Ring-shaped stop plate 31: Bolt 4: Die-cast machine body 41: Mold 42: Platen (die plate)
51: Ceramic cylinder 52: Metal cylinder

Claims (8)

  A front cylindrical body (10), a rear cylindrical body (20) having a hot water supply port connected to the rear end thereof in the axial center, and a ring-shaped stopper attached to the tail end of the rear cylindrical body (20) It consists of a plate (30), the front cylinder (10) is a single-layer cylinder made of metal, and the rear cylinder (20) consists of an inner cylinder (21) made of ceramics and a metal surrounding it. A polymer cylinder with an outer cylinder (22) having a circumferential gap (23) between an inner cylinder (21) made of ceramic and an outer cylinder (22) made of metal, and made of ceramic (21) is a composite sleeve for a die-casting machine, characterized in that it is sandwiched and held in the axial direction between the rear end face of the front cylindrical body (10) and the ring-shaped stopper plate (30).   2. The die casting machine according to claim 1, wherein ceramic fibers are loaded in a circumferential gap (23) between the inner cylinder (21) made of ceramic of the rear cylinder and the outer cylinder (22) made of metal. Composite sleeve.   The outer cylinder (22) of the front cylinder (10) and the rear cylinder (20) is made of hot tool steel, and the inner cylinder (21) of the rear cylinder (20) is made of silicon nitride ceramics. A composite sleeve for a die casting machine according to claim 1 or 2. The inner cylinder (21) made of ceramic of the rear cylinder (20) has a flange (21a) at the front end, and the outer cylinder (22) made of metal is for engaging the flange (21a) of the inner cylinder. while having annular protrusion toward the circumferential direction which is formed in the enlarged diameter stepped (22b) and the front cylinder (10) and (22 _P), the front tubular member (10) in the rear cylinder (20) has an annular projecting portion (10 _P) towards, is connected by mating of the front cylinder body (10) the rear cylinder (20) and the said annular protrusion (10 _P) and (22 _P) The composite sleeve for a die casting machine according to any one of claims 1 to 3, wherein the ring-shaped stopper plate (30) is pressed and fixed to a tail end surface of a metal outer cylinder (22).   The composite sleeve for a die casting machine according to any one of claims 1 to 4, wherein the inner cylinder (21) is a silicon nitride ceramic sintered product such as silicon nitride or sialon.   Low thermal expansion between the flange (21a) of the inner cylinder (21) made of ceramics and the circumferential step (22b) of the outer cylinder (22) made of metal having a lower thermal expansion coefficient than the outer cylinder (22). The composite sleeve for a die-casting machine according to any one of claims 1 to 5, wherein a ring-shaped spacer (25) made of a material is interposed. The low thermal expansion material of the ring spacer (25) is tungsten alloy, molybdenum alloy, titanium alloy, cemented carbide with a thermal expansion coefficient of 1 × 10 ^{−6 to} 7 × 10 ⁻⁶ / ° C. at room temperature to 600 ° C. Or a composite sleeve for a die casting machine according to claim 6, wherein the composite sleeve is a CC composite.   The composite sleeve for a die casting machine according to any one of claims 1 to 7, wherein a division position of the front cylinder (10) and the rear cylinder (20) substantially coincides with an outer surface of the die plate.

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