WO2017095057A1 - Production method of low crank case for engine by hybrid die casting - Google Patents

Production method of low crank case for engine by hybrid die casting Download PDF

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Publication number
WO2017095057A1
WO2017095057A1 PCT/KR2016/013495 KR2016013495W WO2017095057A1 WO 2017095057 A1 WO2017095057 A1 WO 2017095057A1 KR 2016013495 W KR2016013495 W KR 2016013495W WO 2017095057 A1 WO2017095057 A1 WO 2017095057A1
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WIPO (PCT)
Prior art keywords
crank case
low
water
tank
cooling
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Application number
PCT/KR2016/013495
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French (fr)
Korean (ko)
Inventor
이원환
한요섭
장정환
박계주
권종섭
조한준
Original Assignee
인지에이엠티 주식회사
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Publication of WO2017095057A1 publication Critical patent/WO2017095057A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/22—Dies; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
    • B22D17/24—Accessories for locating and holding cores or inserts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D19/00—Casting in, on, or around objects which form part of the product
    • B22D19/04—Casting in, on, or around objects which form part of the product for joining parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D30/00—Cooling castings, not restricted to casting processes covered by a single main group
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing

Definitions

  • the present invention relates to a method for manufacturing a low crank case for an engine by hybrid die casting, and more particularly, to a hybrid die casting in which a bearing insert is inserted into a mold of a low crank case for a vehicle, and molten metal is injected at high speed and high pressure to integrate into a die casting. It relates to a low crank case manufacturing method for an engine.
  • crankcase 1 as shown in FIG. 1 constituting the lower part of the engine was formerly made mainly of cast iron, but has recently been changed to an aluminum material for increasing heat dissipation and lightening in order to pursue high efficiency and high performance products.
  • the aluminum low crankcase 1 is lighter than 40% lighter than a general cast iron crankcase, that is, lighter than 15kg from 25kg to 25kg. This is more than just 15kg weight reduction, improved thermal efficiency and compact engine structure, resulting in more than 5% increase in engine efficiency and more than 3% increase in fuel economy.
  • the aluminum low crankcase 1 has been required to have higher engine load and durability while developing into a high engine speed, a turbo function, a GDI engine, and the like.
  • structural rigidity, durability, and reinforcement and optimization of NVH, etc. are considered and manufactured in the domestic die casting method as in advanced countries.
  • the aluminum low crank case 1 manufactured as described above is a wear-resistant high rigid cast iron bearing insert manufactured in the form of 'M' as shown in FIG. 1 in order to satisfy the characteristics of the high-speed high-power engine ( 10) is fixed to the insert in contact with the crankshaft.
  • the bearing insert 10 reinforces the weak part of the low crank case 1 by rotatably supporting the crank shaft while in contact with the crank shaft not shown in the inserted state.
  • the above-described cast iron bearing insert may be applied to a product registered in the Patent No. 10-0802841 (Applicant; Hyundai Motor Co., Ltd.) of the Korean Intellectual Property Office.
  • These prior art bearing inserts are made of cast iron and have protrusions formed on the surface to provide improved bonding at the time of insert.
  • the low crank case described above has a problem that the fuel consumption of the vehicle is lowered due to the heavy weight and the exhaust gas is increased because the bearing insert is made of cast iron and is inserted. Due to the post-processing, the productivity is lowered, the processing roughness is difficult to manage, there is a problem that the manufacturing cost increases. And, in case of defective products, the same material can be used again by dissolving the material, while regeneration is virtually impossible due to the combination of different materials. In addition, there is a problem that cast iron bearing inserts are found for long-term storage.
  • the above-mentioned aluminum bearing insert may be manufactured by the technology disclosed in Korean Patent No. 10-1500012 (Applicant: Hyundai Motor Co., Ltd.).
  • This prior art shows an aluminum alloy composition composed of 14 to 25 wt% silicon (Si), 2 to 7 wt% copper (Cu), 0.2 to 2.0 wt% magnesium (Mg) and the balance of aluminum (Al).
  • the molten metal is kept at a predetermined temperature in a heating furnace, and 50 to 500 ppm of phosphorus (P) is added to improve the stabilization for a predetermined time, and then a round or square round bar is manufactured through continuous casting, and then round bar
  • P phosphorus
  • the present invention is to manufacture an aluminum bearing insert which is a reinforcing material by cutting a preform in a block form and then hot forging the preform.
  • the applicant of the present invention has developed and applied for a technology for easily manufacturing a bearing insert made of aluminum, and has been registered as a Korean Patent No. 10-1258801.
  • the billet is 'M' type extrusion and then cut to a predetermined thickness to produce a preform.
  • the preform is cut to a size corresponding to the size (thickness and width) of the bearing insert.
  • the preform is made of a completed bearing insert as the thin film-shaped flash that protrudes outwardly by forging is removed by the trimming process.
  • the bearing insert As the bearing insert is processed into a shot blaster, the bearing insert removes lubricants or oxidized foreign substances from the surface during forging, and at the same time, fine concavities and convexities are formed, thereby improving the bondability of the insert.
  • the crankcase 1 in which the cast iron bearing insert 10 is integrally inserted is a hybrid in which the heterogeneous materials having different materials or the dissimilar materials having different physical properties (characteristics) are partially combined. It is manufactured by die casting.
  • the cast iron bearing insert 10 is preheated to a temperature of about 200 ° C. or more, charged into a mold, and then melted at about 650 ° C. Manufacturing is completed by injection molding the metal into the mold cavity by injection molding at a high speed of about 40 m / s and a high pressure of about 500-1000 bar, and then taking out the molding from the mold and cooling it to a temperature of about 20 to 30 °C. do. At this time, the molded product taken out from the mold is cooled by water cooling, so cast iron bearing insert 10 is corroded and must be cooled by air cooling at room temperature. Therefore, the crankcase 1 is manufactured as a hybrid type product in which the cast iron bearing insert 10 and the aluminum material are combined by the above-mentioned die casting and air cooling.
  • crank case 1 is bonded to the molten aluminum metal in the mold in a state in which the cast iron bearing insert 10 is preheated, so that the crank case 1 has excellent adhesion between cast iron and aluminum, and particularly, die casting characteristics due to high pressure molding. Due to this, not only the dimensional accuracy and the reproducibility of the molding are excellent but also the structure is very dense.
  • the mono crank case is a cast iron bearing insert 10 as described above due to the characteristics of aluminum, which causes a sharp drop in strength due to annealing at a temperature of about 200 ° C. or more.
  • the application of the method of making) is not suitable. That is, the mono crank case may have a decrease in physical properties (decrease in strength) when manufactured by the above-described method due to the material properties of the aluminum bearing insert.
  • the aluminum bearing insert of the 'M' type is preheated like a cast iron insert, charged into a die casting mold, and then die cast aluminum molten metal at about 650 ° C.
  • the aluminum bearing insert which is joined to the hot aluminum molten metal in a preheated state, is not only rapidly heated by the aluminum molten metal to about 500 ° C.
  • the mechanical properties of the aluminum alloy have a melting point of about 550-600 °C lower than that of cast iron. Rapidly deteriorates, due to long air cooling time There is a problem that productivity is lowered due to increased cycle time.
  • the hybrid die casting method is only to satisfy only simple bonding, and does not achieve the change and improvement of the manufacturing method according to the material of the insert, the present invention by long-term research and experiment to improve this To apply for.
  • the present invention is to solve the above problems, in a hybrid die casting that can improve productivity by shortening the molding cycle time of the die casting while minimizing the reduction of mechanical properties of the aluminum bearing insert in the hybrid die casting integrated by casting It is an object of the present invention to provide a method for manufacturing a low crank case for an engine.
  • Insert charging step of charging the bearing insert of the alloy material A die casting step of molding a low crank case by injecting molten metal into the mold cavity at a high speed and high pressure after the insert charging step; Taking out the low crank case from the mold cavity after the die casting step; And a cooling step of rapidly cooling the low crank case after the take-out step, wherein the cooling step is characterized in that the low crank case is rapidly cooled by water cooling through a cooling water of a tank.
  • the bearing insert is preferably inserted into the cavity of the die casting mold, for example at a temperature of room temperature.
  • the cooling step may include, for example, a tank charging step of charging the taken out low crank case into the tank in which cooling water is stored; Immersing the low crank case charged in the tank in the cooling water of the tank for a predetermined time; And a withdrawal step of withdrawing the low crankcase from the water tank.
  • the submerging step for example, it is preferable to submerge the low crankcase in the cooling water of the water tank for a suitable time to cool the low crankcase to 130 ° C to 190 ° C.
  • the cooling water circulation step may include, for example, a new cooling water corresponding to the amount of cooling water discharged while discharging the cooling water of a portion of the cooling water of the tank to the outside of the tank so that the cooling water is circulated while exchanging a portion of the cooling water stored in the tank.
  • Cooling water exchange step to replenish the tank can be configured.
  • the cooling water circulation step, the stirring blade is provided in the inside of the water tank to agitate the cooling water to circulate the cooling water in the water tank; may be configured as.
  • the present invention may further include a vibration step of increasing heat exchange between the coolant and the low crankcase by vibrating at least one of the low crankcase charged in the water tank and an elevator for charging the low crankcase into the water tank.
  • the present invention further includes a water removal step of removing water from the low crank case drawn out by cooling in the water tank.
  • the water removal step may include: a room temperature standing step of leaving the low crank case at room temperature while the water of the low crank case is dried to remove water from the low crank case drawn out of the water tank. have.
  • the water removing step may include, for example, an air blowing step of removing the water from the surface of the low crankcase by injecting the compressed air into the surface of the low crankcase by drawing the low crankcase from the water tank.
  • the water removal step may further include a drying step of naturally drying the low crank case from which water is removed by the compressed air after the air blowing step.
  • the present invention may further include a trimming step of removing a hot mouth formed in the low crankcase after the cooling step.
  • the present invention may further include an annealing step of removing the internal stress by heat treating the low crank case after the cooling step.
  • the molten metal is filled into the mold and the temperature of the low crank case is about 400.
  • the low crankcase is cooled rapidly so that the molten metal can be solidified rapidly and cooled by a bearing insert at a temperature lower than the normal preheating temperature of about 200 degrees, thereby shortening the molding time.
  • the low crank case to which the bearing insert is bonded is rapidly cooled, which greatly reduces the time for exposing the bearing insert to high temperature. have. Therefore, the bearing insert can be prevented from deteriorating in physical properties due to thermal stress.
  • the preheating process of the bearing insert used in the prior art can be omitted, which can shorten the time required for the entire production process due to the elimination of the preheating time, thereby increasing productivity, and inserting the low crankcase into the cooling water of the tank. Therefore, since the cooling is performed by water cooling, the low crankcase can be cooled easily and quickly, thereby improving the productivity of the low crankcase.
  • the low crank case is submerged in the cooling water of the tank for a predetermined time, thereby substantially reducing the cooling time, thereby efficiently managing the entire production cycle of the low crank case, and in addition, the aluminum material rapidly increases at a temperature of about 200 ° C. or more. Since the softening reduces mechanical properties, the low crankcase is cooled in a water bath at a temperature of about 130-190 ° C. to prevent deterioration of the properties of the bearing insert and to secure latent heat for the drying process.
  • the cooling water in the tank can be circulated, the water temperature stored in the tank can be prevented from rising or water bubbles can be generated from the cooling water, thereby not only cooling the low crankcase as a whole, but also water on the surface of the low crankcase. It is possible to prevent the formation of bubbles, and to replenish the new coolant corresponding to the discharge while discharging a part of the stored coolant, so that the stored coolant can be lowered even when the temperature of the stored coolant rises, as well as the coolant water temperature. Water bubbles can be prevented from being lowered, and when the cooling water is stirred, the water temperature rise and the water bubble phenomenon of the cooling water can be further prevented, and the low crankcase can be cooled evenly.
  • the cooling water flows by vibrating the elevator or low crank case submerging the low crank case in the water tank, not only the low crank case can be heat exchanged smoothly with the cooling water, but also water bubbles can be prevented from being generated.
  • the low crank case is left to remove moisture from the low crank case through the latent heat of the low crank case, so that the drying process can be easily performed, and the low crank case can be completely completely dried.
  • FIG. 1 is a perspective view showing a low crank case and a cast iron bearing insert for a conventional engine.
  • FIG. 2 is a perspective view showing a low crank case and an aluminum bearing insert for a lightweight insert engine.
  • FIG. 3 is a flowchart illustrating a method of manufacturing a low crank case for a hybrid die casting engine according to an embodiment of the present invention.
  • Figure 4 is a schematic diagram showing a cooling step of the manufacturing method according to an embodiment of the present invention.
  • Figure 5 is a schematic diagram showing an air blowing step of the manufacturing method according to an embodiment of the present invention.
  • FIG. 6 is a physical property table comparing the physical properties of the aluminum insert of the engine low crank case manufactured by the embodiment of the present invention.
  • Hybrid cranking engine low crank case manufacturing method insert charging step (S10), die casting step (S20), take-out step (S30), cooling step (S40) as shown in FIG. ) In that order.
  • the present invention relates to a manufacturing method for inserting and inserting a bearing insert for supporting a crankshaft by casting into a low crankcase constituting a lower part of an engine.
  • a bearing insert as described in the prior art is molded.
  • an aluminum alloy is hot-forged by an aluminum alloy composition composed of 10 to 13 wt% silicon (Si), 3 to 6 wt% copper (Cu), 0.3 to 1.0 wt% magnesium (Mg), and a balance of aluminum (Al).
  • an aluminum alloy composition composed of 10 to 13 wt% silicon (Si), 3 to 6 wt% copper (Cu), 0.3 to 1.0 wt% magnesium (Mg), and a balance of aluminum (Al).
  • the physical properties of the bearing insert are hardness HRB 80 ⁇ 85, tensile strength 400 ⁇ 450 MPa, yield strength 350 ⁇ 380 Mpa.
  • an insert charging step (S10) of inserting it into the cavity of the die casting mold for forming the low crankcase is performed, wherein the bearing insert charged into the cavity of the die casting mold has a high temperature unlike a general method. It is loaded into the mold without preheating, and the robot can be used to load the bearing inserts.
  • the above-mentioned bearing insert may be charged at a temperature of about 10 ° C to 50 ° C, but is preferably loaded at a room temperature (about 15 ° C to 35 ° C).
  • the bearing insert When the bearing insert is loaded at 10 ° C. or less, the difference in temperature with the high temperature molten aluminum metal described later may be so severe that the bonding property may be degraded. (Molding time) cannot be planned.
  • a die casting step S20 is performed in which molten metal is injected at a high speed and high pressure into the cavity of the die casting mold to form a low crankcase.
  • the bearing insert is loaded into the cavity of the die casting mold precisely and quickly by using a robot.
  • the cavity of the die casting mold is about 120 ⁇
  • the bearing insert is charged and the die casting mold is closed to close.
  • the molten metal is injected into the cavity of the die casting mold at a pouring speed of 40 m / s or more and a pressing force of 800 bar to fill the cavity within 0.1 sec.
  • the molten metal may be an aluminum to aluminum alloy composition, the temperature of the molten metal is about 650 °C.
  • the die and the mold insert of the die casting respectively come into contact with the molten metal to absorb the heat of the molten metal so that the molten metal solidifies into a shape corresponding to the cavity shape of the die casting mold.
  • the temperature difference between the die casting mold and the molten metal is about 450 ° C, and the temperature difference between the bearing insert and the molten metal is about 630 ° C.
  • the solidification time of the molten metal injected into the mold i.e., the time of forming into the low crankcase, is reduced by about 10% compared to preheating the bearing insert. At this time, the bearing insert is reduced thermal stress caused by the molten metal.
  • the bearing insert is charged into the mold at a temperature of room temperature, which is not preheated, the temperature difference with the molten metal is greater than that of the preheating, and the temperature of the room temperature is room temperature. Thermal stress is reduced when preheated because it is heated to a lower temperature than in the preheated state. Therefore, the bearing insert is suppressed as much as possible due to the change in physical properties of the molten metal due to the high heat, that is, the decrease in strength due to loosening. In particular, the bearing insert is shortened the solidification time of the molten metal as described above to minimize the time to be exposed to high heat or heated by high heat, thereby reducing the strength decrease as much as possible.
  • taking out step (S30) for taking out from the cavity of the die casting mold is to take out the low crank case solidified in the cavity of the die casting mold using a robot.
  • the temperature at the time of taking out the low crankcase from the cavity of the die casting mold is about 400 to 450 ° C., so that the low crankcase is deformed and damaged due to the low strength of the mill crank that pushes the low crankcase out of the die casting mold. Can be prevented.
  • the take-out temperature of the low crank case is lower than 400 ⁇ 450 °C, the molding cycle time of the die casting is increased to reduce the productivity, it is preferable that the take out temperature of the low crank case in the die casting mold is 400 ⁇ 450 °C.
  • Cooling step (S40) is a low crank case taken out of the die at a temperature of 400 ⁇ 450 °C as quickly as possible to minimize the degradation of the physical properties of the aluminum material, so that the low crank case taken out of the die casting mold as shown in Figure 4 Likewise, it is charged into a water tank containing coolant and rapidly cooled by water cooling. That is, the cooling step (S40) is rapid cooling by water-cooling so that the low crank case of 400 ⁇ 450 °C is a temperature of about 200 °C or less at the beginning of the decrease of physical properties of aluminum in the shortest time.
  • the cooling step S40 may include, for example, a tank charging step of charging the extracted low crank case into the cooling water of the tank; Submerging the low crank case charged in the tank to the cooling water of the tank for a predetermined time; And a withdrawal step of withdrawing the low crankcase from such a water tank. That is, the cooling step (S40) may be composed of the tank charging step, the submerging step and the withdrawal step.
  • the tank charging step charges the extracted low crank case deeply into the bottom of the tank through a device such as a conventional robot.
  • a device such as a conventional robot.
  • the low crank case taken out at 400 ⁇ 450 ° C is charged into the water tank, the water temperature of the coolant contacting the surface of the low crank case rises rapidly and vaporizes. Water bubbles are formed in the tank.
  • the low crankcase is partially blocked by the water bubble and the cooling is delayed, and in particular, the water bubble cannot be smoothly discharged because the molded hollow part or the complicated shape part is not smoothly discharged, and only the specific part is rapidly cooled.
  • Non-uniform cooling that is slow cooled is intensified.
  • the low crankcase partly causes a large cooling difference, and the temperature is not uniform, resulting in an increase in thermal deformation, an increase in residual stress in the product, and a decrease in cooling rate. Therefore, the tank charging step charges the low crank case taken out deeply into the bottom of the tank as shown in FIG. 4 so that the rapid rise in water temperature of the cooling water and the generation of water bubbles are suppressed as much as possible.
  • the submerging step submerges the low crankcase in the coolant of the tank for a time set to cool the low crankcase to 200 degrees or less, in particular 130 degrees to 190 degrees.
  • the above-described settle time is preferably about 15 seconds to 32 seconds, and most preferably about 20 seconds. If the submersion time is less than 15 seconds, the low crankcase is not cooled to the above-mentioned temperature, and if more than 32 seconds, the manufacturing time is excessively excessive, causing a disruption in the mass production cycle. Therefore, the sleep time needs to be limited to within about 15 seconds to 32 seconds.
  • the sleep time is most suitable about 20 seconds according to the experiment of the applicant of the present invention. Because, the settled time is typically the mass production time of the low crankcase is 60 seconds to 90 seconds, and the work robot loads the bearing insert into the mold, takes it out, loads it into the water tank, and performs the related work until trimming described later. This is because about 20 seconds is most suitable.
  • the withdrawal step removes from the water tank the low crankcase which was submerged in the water bath for the above-mentioned time and cooled to the above-mentioned temperature. At this time, the low crankcase is quickly removed from the water tank so that the aforementioned cooling time is not exceeded. This withdrawal step is omitted because the low crankcase is removed from the water tank by a conventional method using a device such as a robot.
  • the water tank may cool the low crankcase only when the water temperature of the coolant is maintained at about 20 to 50 ° C.
  • the bath may be heated as the low crank case of about 400 ⁇ 450 °C is charged as described above.
  • the water tank is difficult to rapidly cool the low crankcase to the above-mentioned temperature when the coolant is heated and the water temperature rises.
  • the water tank may generate more water bubbles as described above when another low crank case is charged while the cooling water is heated.
  • the water tank 20 is a low crank case (see Fig. 4) so that the low crank case 1 is charged deeply so that the crank case 1 does not generate water bubbles without affecting the water temperature change. It is preferably manufactured to a depth of at least three times or more than the height of 1), the cooling water is circulated by the cooling water circulation step described later.
  • the water tank 20 may store, for example, about 0.8 to 2.5 tons of coolant to sufficiently cool the low crankcase 1 without the water temperature of the coolant rapidly increasing by the charged low crankcase 1. It is formed to a size. To this end, the water tank 20 is configured to have a width and length of about 1.5m to 2.5m and a depth of about 1.5m to 2m.
  • the cooling water circulation step circulates the cooling water stored in the water tank 20 to not only suppress the rise of the water temperature of the cooling water but also suppress the occurrence of water bubbles in the cooling water to the maximum.
  • This cooling water circulation step may be configured as at least one of the cooling water exchange step and / or cooling water stirring step.
  • the cooling water exchange step some of the cooling water of the cooling water of the water tank 20 is discharged to the outside of the water tank 20 so that a portion of the cooling water stored in the water tank 20 is circulated, and at the same time, the amount of cooling water discharged. Refill the water tank 20 with a new coolant.
  • the water tank 20 is provided with a water supply pipe 20a adjacent to the low crank case 1 as shown in FIG. 4, and a drain pipe 20b is installed to face the water supply pipe 20a. A portion of the coolant stored in the water tank 20 is discharged through the drain pipe 20b, and the stored coolant is circulated as new coolant is replenished through the water supply pipe 20a.
  • the coolant supplied through the water supply pipe 20a is discharged through the drain pipe 20b after heat exchange with the low crank case 1, the temperature of the coolant may not be substantially raised by the low crank case 1.
  • the low crankcase 1 is cooled quickly.
  • the water tank 20 increases only the water temperature of the cooling water by about 1 ° C. to about 12 ° C. according to the amount of supply and discharge of the cooling water described above.
  • the temperature of the water was raised only within 1 ° C to 3 ° C, except in special cases (eg, when the temperature was high due to the summer season and heat waves), which did not significantly affect the cooling of the low crankcase 1. Therefore, the water tank 20 cools the low crankcase 1 to the above-mentioned cooling temperature of about 130 ° C to 190 ° C as cooling water is supplied through the water supply pipe 20a to maintain the water temperature of the cooling water at a desired temperature. I could make it.
  • the water tank 20 should be configured to supply and discharge the cooling water in an amount such that the temperature of the cooling water can only rise to about 1 ° C to about 12 ° C.
  • the cooling water temperature of about 20-50 ° C. is forced to rise to about 1 ° C., but the cooling water temperature of about 20-50 ° C. is about 12 ° C. or more.
  • the cooling cycle exceeds the set cooling time of the low crank case 1 described above. Therefore, the water tank 20 should be supplied and discharged so that the cooling water temperature of about 20-50 ° C rises only from about 1 ° C to about 12 ° C as described above.
  • the low crankcase 1 should be cooled to 200 ° C. or lower because there is a risk of property change (softening effect) due to the characteristics of the aluminum material when cooled to about 200 ° C. or higher.
  • the temperature is lower than 200 ° C. and lower than 200 ° C., the temperature is close to 200 ° C., and thus the cooling to 190 ° C. or lower is preferable as described above in order to reliably prevent a change in physical properties.
  • the low crankcase takes too much drying time during natural drying described below when cooled to 130 ° C. or less.
  • the low crankcase is removed by evaporating water through its own heat, that is, latent heat, during natural drying, which will be described later.
  • the latent heat is weak, so that the water cannot be evaporated smoothly, and it is difficult to remove residual water by air blowing described below. Therefore, the low crankcase is preferably cooled to a temperature of 130 ° C or higher.
  • the cooling water stirring step described above is circulated while stirring the cooling water through the stirring blade 23 provided in the interior of the water tank 20 as shown in FIG.
  • the water tank 20 is provided with stirring blades 23 adjacent to the low crank case 1 submerged in the cooling water as shown.
  • the stirring vane 23 rotates the cooling water while rotating, thereby actively condensing the cooling water. Therefore, the water tank 20 can not only prevent the temperature rise of the coolant but also cool the low crankcase 1 more quickly.
  • the low crank case 1 is immersed in the water tank 20 through the elevator 21 as shown in FIG. 4 so as to quickly and stably immersed in the water tank 20.
  • Such an elevator 21 has a low crank case 1 settled out of a mold through a normal robot.
  • the low crank case 1 may be vibrated through the vibrating step S41 so as to be submerged in the water tank 20 to prevent heat generation while smoothly exchanging heat.
  • This vibration step S41 vibrates the low crank case 1 through the vibrator 22 shown in FIG.
  • the vibrator 22 may be installed in the low crank case 1 to vibrate the low crank case 1 directly.
  • the vibrator 22 may be installed in the above-described elevator 21 to provide a low crank through the vibration of the elevator 21.
  • the case 1 may also be vibrated.
  • the vibrator 22 vibrates the coolant of the water tank 20 by vibrating the low crankcase 1, so that the low crankcase 1 can be heat-exchanged smoothly and prevents water bubbles from being generated. .
  • At least one of the water removal step, the trimming step S70 and the annealing step S80 may be performed after the cooling step S40 is performed.
  • the water removal step is a process of removing water from the low crank case 1 of about 130 ° C to 190 ° C removed by being removed from the water tank 20.
  • the room temperature of the low crank case 1 is allowed to stand at room temperature during the time that the water of the low crank case 1 dries so that water is dried in the low crank case 1 withdrawn from the water tank 20. It can be configured as a neglect step. That is, the low crank case 1 may be cooled again to the air-cooled cooling step after the water-cooled cooling step. In the room temperature leaving step, the low crank case 1 is left to dry at room temperature until the water naturally evaporates by the temperature of the low crank case 1.
  • the water removal step is preferably composed of an air blowing step (S50) and drying step (S60) to be described later. That is, the additional air-cooled cooling step after the water-cooled cooling step may be composed of an air blowing step (S50) and a drying step (S60).
  • the air blowing step S50 is performed while the low crank case 1 of about 130 ° C. to 190 ° C. where the cooling step S 40 is completed is placed on the conveyor 30 to move the blower 40.
  • the compressed air is sprayed on the surface of the low crank case 1 to remove moisture from the surface of the low crank case 1. Accordingly, the low crank case 1 is cooled as the surface is dried as well as contamination by moisture does not occur on the surface.
  • the low crank case 1 is removed while the water of the hollow portion formed on the surface or the portion formed into a complicated shape is scattered by the compressed air.
  • the drying step S60 is a process after the air blowing step S50 is performed.
  • the low crank case 1 is naturally dried through the air blowing step S50.
  • the low crank case 1 is evaporated by the heat that the water remaining on the surface itself dissipates.
  • This drying step (S60) cools the low crank case 1 to a temperature of approximately 30 °C to 50 °C.
  • Trimming step (S70) is to remove the tang (Gate) of the low crank case 1 formed in the die casting step (S20), the low crank case of the drying step (S60) is completed is transferred to the trimming press device to remove the tanggu Done.
  • the annealing step S80 is a process of strengthening the strength of the low crankcase 1 by heat-treating the cooled low crankcase 1 so as to reinforce the physical properties of the bearing insert which is somewhat weakened during die casting molding.
  • the annealing step (S80) may be carried out after the water-cooled and / or additional air-cooled cooling step, particularly preferably after the trimming step after this cooling step is performed.
  • the low crank case 1 is transferred to an annealing device, not shown, to heat-process the low crank case 1.
  • This annealing step S80 heats the low crank case 1 to a constant temperature and then cools it slowly to even out internal tissues and remove stress.
  • the annealing step (S80) is carried out after the low crankcase (1) at a temperature of 200 °C for about 2 hours to remove the residual stress of the low crankcase (1) due to rapid cooling by the cooling step (S40) and aging after high temperature quenching Reinforcement is applied to obtain the effect of strength increase.
  • the "die-casting all-material insert” indicated in the property table is the property of the hot-forged aluminum bearing insert, that is, the bearing insert before being charged into the die-casting die.
  • “Example insert” is the physical property of an aluminum bearing insert joined to a low crankcase by the manufacturing method of the present invention.
  • “Comparative Example Insert” is the physical property of an aluminum bearing insert that is pre-heated, charged into a die casting mold, die cast and then cooled by air cooling as described in the prior art.
  • the "die-casting all material insert” has a mechanical property of hardness 80 ⁇ 85 HRB, tensile strength 400 ⁇ 450 MPa, yield strength 350 ⁇ 380 MPa.
  • "Comparative Example Insert” has a mechanical property of hardness 50 ⁇ 55 HRB, tensile strength 250 ⁇ 300 MPa, yield strength 220 ⁇ 250 MPa.
  • the bearing insert produced by the manufacturing method of the present invention has a mechanical property of hardness 70 ⁇ 75 HRB, tensile strength 350 ⁇ 380 MPa, yield strength 3000 ⁇ 330 MPa.
  • the bearing insert of the "Comparative insert” has about 35% decrease in physical properties compared to the "die-casting all material insert", but the “Example insert” produced by the present invention has about 13% of the physical property. Since it is reduced, the quality of the bearing insert manufactured according to the present invention is satisfied, and it is shown that the function can be sufficiently performed as a product.
  • the "comparative example insert” described above is in contact with the molten metal while the aluminum bearing insert is preheated to a temperature of about 200 ° C., and left at room temperature for a long time at a temperature of about 400 ° C. to 500 ° C. for air cooling. As this occurs, it is believed that the mechanical properties are weaker than the "Example insert" according to the embodiment of the present invention.
  • the “embodiment insert” according to the embodiment of the present invention described above has lowered the temperature of the molten metal injected into the mold by the unpreheated bearing insert, so that the bearing insert is not substantially exposed to high temperature unlike the "comparative insert". As a result, the molding time is shortened according to the temperature decrease of the molten metal, and the duration of the high temperature state of the bearing insert is shortened. .
  • the aluminum bearing insert is not preheated, and charged into the mold at a temperature of room temperature as in the embodiment of the present invention and then molded in the mold with molten metal as described above, not water-cooled
  • the characteristics were almost similar to those of the "Comparative Example insert" described above. Accordingly, the low crank case molded in the same manner as in the embodiment of the present invention and then cooled by air cooling was weaker in mechanical properties than the "example insert" according to the present invention. It is considered that the lower crank case is left at room temperature for a long time at a temperature close to the melting point of the aluminum alloy, thereby deteriorating physical properties due to the unwinding phenomenon.
  • the temperature of the low crank case in the die casting mold is taken out when the temperature of 400 ⁇ 450 °C, charged into the cooling water of the tank to rapidly cool the low crank case Since the drawing is carried out when the temperature is 150 ° C., the molding cycle time of die casting can be shortened to improve productivity.
  • the bearing insert since the low crankcase is withdrawn from the water tank when the temperature of the low crankcase is 150 ° C, the bearing insert may not be softened, and water may be evaporated by latent heat of the low crankcase. It is possible to prevent contamination on the surface of the crankcase.

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  • Cylinder Crankcases Of Internal Combustion Engines (AREA)
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Abstract

The present invention relates to a production method of a low crank case by hybrid die casting. The present invention comprises: an insert charging step for charging an insert made of an alloy into a cavity of a die casting mold; a die casting step for casting a low crank case by filling a melt metal into the mold cavity in which the insert is charged; a removal step for removing the low crank case from the mold; and a cooling step for rapidly cooling the removed low crank case. The present invention can prevent the deterioration of physical properties caused by annealing due to the rapid cooling.

Description

하이브리드 다이캐스팅에 의한 엔진용 로우 크랭크 케이스의 제조방법Manufacturing method of low crank case for engine by hybrid die casting
본 발명은 하이브리드 다이캐스팅에 의한 엔진용 로우 크랭크 케이스 제조방법에 관한 것으로, 더욱 상세하게는 베어링 인서트를 차량용 로우 크랭크 케이스의 금형에 장입하고, 용융금속을 고속 고압으로 사출하여 다이캐스팅으로 일체화하는 하이브리드 다이캐스팅에 의한 엔진용 로우 크랭크 케이스 제조방법에 관한 것이다.The present invention relates to a method for manufacturing a low crank case for an engine by hybrid die casting, and more particularly, to a hybrid die casting in which a bearing insert is inserted into a mold of a low crank case for a vehicle, and molten metal is injected at high speed and high pressure to integrate into a die casting. It relates to a low crank case manufacturing method for an engine.
자동차에서 엔진은 가장 중요한 부품이며 세계적인 환경 규제와 고유가에 대응한 고연비 친환경의 그린 차량 엔진 제품의 생산은 자동차업계의 생존에 필수 조건이 되고 있다. 국내에서도 기존의 엔진에서 고효율 친환경, 고출력의 수요에 대응하는 새로운 엔진으로 신속하게 개발이 되고 있다.Engines are the most important parts in automobiles, and production of high-efficiency, green vehicle engine products in response to global environmental regulations and high oil prices is becoming a prerequisite for the survival of the automotive industry. Even in Korea, it is rapidly developing into a new engine that meets the demand for high efficiency, eco-friendliness and high power from existing engines.
엔진의 하부 부품을 구성하는 도 1에 도시된 바와 같은 크랭크 케이스(1)가 예전엔 주로 주철로 제조되었으나, 최근 고효율 및 고성능 제품을 추구하기 위해 방열성을 높이고 경량화를 위한 알루미늄 소재로 변경되고 있다.The crankcase 1 as shown in FIG. 1 constituting the lower part of the engine was formerly made mainly of cast iron, but has recently been changed to an aluminum material for increasing heat dissipation and lightening in order to pursue high efficiency and high performance products.
이러한 알루미늄 로우 크랭크 케이스(1)는 일반 주철제 크랭크 케이스에 비하여 40% 이상 경량화, 즉 40kg 대에서 25kg 대로 15kg 이상 경량화되었다. 이것은 단순히 중량이 15kg 감소의 의미를 넘어서 열효율과 컴팩트한 엔진 구조로 개선을 이루어 엔진효율의 5% 이상 상승 및 연비 3% 이상 상승의 효과를 가져 오게 되었다.The aluminum low crankcase 1 is lighter than 40% lighter than a general cast iron crankcase, that is, lighter than 15kg from 25kg to 25kg. This is more than just 15kg weight reduction, improved thermal efficiency and compact engine structure, resulting in more than 5% increase in engine efficiency and more than 3% increase in fuel economy.
최근, 알루미늄 로우 크랭크 케이스(1)는 엔진의 고회전수, 터보 기능, GDI 엔진 등으로 발전하면서 보다 고엔진 부하와 내구성이 요구되고 있다. 이를 위하여 구조적인 강성과 내구성, NVH 등의 보강과 최적화가 고려되어 국내에서도 선진국과 같이 알루미늄 다이캐스팅 공법으로 제조되고 있다.In recent years, the aluminum low crankcase 1 has been required to have higher engine load and durability while developing into a high engine speed, a turbo function, a GDI engine, and the like. To this end, structural rigidity, durability, and reinforcement and optimization of NVH, etc. are considered and manufactured in the domestic die casting method as in advanced countries.
전술한 바와 같이 제조되는 알루미늄 로우 크랭크 케이스(1)는, 고회전 고출력 엔진의 특성을 만족시키기 위하여 도 1에 도시된 바와 같이 'M'과 같은 형태로 제조된 내마모 고강성의 주철재 베어링 인서트(10)가 크랭크 축과 접촉하는 부분에 인서트로 고정된다. 베어링 인서트(10)는 인서트된 상태로 미도시된 크랭크 축과 접촉하면서 크랭크 축을 회전가능하게 지지하여 로우 크랭크 케이스(1)의 취약부위를 보강한다.The aluminum low crank case 1 manufactured as described above is a wear-resistant high rigid cast iron bearing insert manufactured in the form of 'M' as shown in FIG. 1 in order to satisfy the characteristics of the high-speed high-power engine ( 10) is fixed to the insert in contact with the crankshaft. The bearing insert 10 reinforces the weak part of the low crank case 1 by rotatably supporting the crank shaft while in contact with the crank shaft not shown in the inserted state.
여기서, 전술한 주철재 베어링 인서트는 대한민국 특허청의 등록특허 제10-0802841호(출원인; 현대자동차 주식회사)로 특허등록된 제품이 적용될 수 있다. 이러한 종래기술의 베어링 인서트는 주철로 제조되며, 표면에 돌기가 형성되어 인서트시 향상된 접합성을 제공한다.Here, the above-described cast iron bearing insert may be applied to a product registered in the Patent No. 10-0802841 (Applicant; Hyundai Motor Co., Ltd.) of the Korean Intellectual Property Office. These prior art bearing inserts are made of cast iron and have protrusions formed on the surface to provide improved bonding at the time of insert.
그러나, 전술한 로우 크랭크 케이스는 베어링 인서트가 주철재로 제조되어 인서트되므로 고중량에 의해 차량연비가 저하되고, 배기가스가 증가하는 문제가 있으며, 이에 더하여 주철과 알루미늄을 동시 가공하게 되어 상이한 절삭 조건에 따른 후가공으로 인하여 생산성이 저하되고, 가공조도 관리가 어려워져서 제조단가가 높아지는 문제가 있다. 그리고, 불량품 발생시 동일 재질일 경우 다시 용해하여 사용이 가능한 반면, 이종재의 결합으로 인하여 사실상 재생이 불가능하다. 또한, 주철재 베어링 인서트가 장기 보관시 발청되는 문제도 있다.However, the low crank case described above has a problem that the fuel consumption of the vehicle is lowered due to the heavy weight and the exhaust gas is increased because the bearing insert is made of cast iron and is inserted. Due to the post-processing, the productivity is lowered, the processing roughness is difficult to manage, there is a problem that the manufacturing cost increases. And, in case of defective products, the same material can be used again by dissolving the material, while regeneration is virtually impossible due to the combination of different materials. In addition, there is a problem that cast iron bearing inserts are found for long-term storage.
한편, 최근 들어 일본의 혼다와 독일의 BMW 등은 고유가에 대응하면서 배기가스 규제에 적극적으로 대응하고자 엔진의 경량화 및 경량소재화 기술을 개발하여 전술한 주철재 베어링 인서트를 제거하고, 대신 도 2에 도시된 바와 같은 고강도 알루미늄 합금으로 제조된 베어링 인서트를 적용하여 도시된 바와 같은 모노 크랭크 케이스를 양산할 예정이다. 이러한 모노 크랭크 케이스는 엔진 부품의 경량화를 20% 이상 도모할 수 있으므로 새로운 친환경차량으로 대두되고 있다. 즉, 최근에는 알루미늄재 베어링 인서트를 알루미늄재 크랭크 케이스에 인서트시키는 기술이 개발되어 보급될 예정이다.On the other hand, recently, Honda of Japan, BMW of Germany, and the like have developed the light weight and lightweight material technology of the engine to cope with high gas prices and actively regulate the exhaust gas, thereby removing the cast iron bearing inserts described above. A bearing insert made of high strength aluminum alloy as shown will be applied to mass produce a mono crank case as shown. These mono crankcases can be made lighter in engine parts by more than 20%, which is emerging as a new eco-friendly vehicle. That is, recently, a technology for inserting an aluminum bearing insert into an aluminum crankcase will be developed and spread.
여기서, 전술한 알루미늄 베어링 인서트는 대한민국 특허청의 등록특허 제10-1500012호(출원인: 현대자동차 주식회사)에 개시된 기술로 제조될 수 있다. 이러한 종래기술은 14 ~ 25 wt% 실리콘(Si), 2 ~ 7 wt% 구리(Cu), 0.2 ~ 2.0 wt% 마그네슘(Mg) 및 잔량의 알루미늄(Al)으로 구성된 알루미늄 합금 조성물을 도 3에 도시된 바와 같이 용해한 후 용탕을 보온로에서 소정 온도로 유지하고 인(P)을 50 ~ 500ppm 첨가하여 소정 시간 안정화시키는 개량화 처리를 한 다음, 연속 주조를 통해 원형이나 사각의 환봉을 제조한 후 다시 환봉을 절단하여 블럭형태의 프리폼(Preform)으로 제조한 다음 프리폼을 열간단조하여 보강물질인 알루미늄 베어링 인서트를 제조하는 발명이다.Here, the above-mentioned aluminum bearing insert may be manufactured by the technology disclosed in Korean Patent No. 10-1500012 (Applicant: Hyundai Motor Co., Ltd.). This prior art shows an aluminum alloy composition composed of 14 to 25 wt% silicon (Si), 2 to 7 wt% copper (Cu), 0.2 to 2.0 wt% magnesium (Mg) and the balance of aluminum (Al). After melting, the molten metal is kept at a predetermined temperature in a heating furnace, and 50 to 500 ppm of phosphorus (P) is added to improve the stabilization for a predetermined time, and then a round or square round bar is manufactured through continuous casting, and then round bar The present invention is to manufacture an aluminum bearing insert which is a reinforcing material by cutting a preform in a block form and then hot forging the preform.
그러나, 이러한 종래기술은 블럭형태의 프리폼을 곧바로 열간단조하여야 하므로 단조 시 약 49,000톤의 압력으로 프리폼을 단조해야 한다. 따라서, 전술한 종래기술은 구현이 사실상 매우 어렵다.However, such a prior art has to hot forge the block-shaped preforms immediately, and therefore, forge the preforms at a pressure of about 49,000 tons. Therefore, the above-mentioned prior art is in fact very difficult to implement.
따라서, 본 발명의 출원인은 알루미늄재의 베어링 인서트를 용이하게 제조할 수 있는 기술을 개발 및 특허출원하여 대한민국 특허청에 등록 제10-1258801호로 등록받은 바가 있다. 이러한 본 발명의 출원인에 의한 발명은, 알루미늄 합금의 용탕으로 빌렛을 제조한 후, 빌렛을 'M'형 압출한 다음 설정된 두께로 절단하여 프리폼을 제조한다. 이때, 프리폼은 베어링 인서트의 크기(두께 및 폭)에 대응하는 크기로 절단된다. 그리고, 프리폼은 단조 후, 단조에 의해 외측으로 돌출된 박막형의 플래쉬가 트리밍 공정에 의해 제거됨에 따라 완성된 베어링 인서트로 제조된다.Therefore, the applicant of the present invention has developed and applied for a technology for easily manufacturing a bearing insert made of aluminum, and has been registered as a Korean Patent No. 10-1258801. According to the present invention by the applicant of the present invention, after manufacturing the billet from the molten aluminum alloy, the billet is 'M' type extrusion and then cut to a predetermined thickness to produce a preform. At this time, the preform is cut to a size corresponding to the size (thickness and width) of the bearing insert. After the forging, the preform is made of a completed bearing insert as the thin film-shaped flash that protrudes outwardly by forging is removed by the trimming process.
이러한 베어링 인서트는 쇼트 블러스터로 표면이 가공됨에 따라 단조시 표면에 있는 윤활제나 산화 이물질을 제거하며, 동시에 미세한 요철이 형성되므로 인서트 시의 접합성이 향상된다.As the bearing insert is processed into a shot blaster, the bearing insert removes lubricants or oxidized foreign substances from the surface during forging, and at the same time, fine concavities and convexities are formed, thereby improving the bondability of the insert.
한편, 전술한 도 1에 도시된 바와 같이 주철재 베어링 인서트(10)가 일체로 인서트된 크랭크 케이스(1)는 재질이 서로 상이한 이종재 또는 물성(특성)이 서로 상이한 이종재료를 부분적으로 복합화하는 하이브리드 다이캐스팅에 의해 제조된다.Meanwhile, as shown in FIG. 1, the crankcase 1 in which the cast iron bearing insert 10 is integrally inserted is a hybrid in which the heterogeneous materials having different materials or the dissimilar materials having different physical properties (characteristics) are partially combined. It is manufactured by die casting.
이를 좀더, 자세히 설명하면, 도 1에 도시된 크랭크 케이스(1)를 제조하기 위해서는, 주철재 베어링 인서트(10)를 약 200℃ 이상의 온도로 예열하여 금형에 장입한 후, 약 650℃의 알루미늄 용융금속을 약 40m/s의 고속과 약 500-1000bar의 고압으로 금형의 캐비티에 사출로 충전하여 다이캐스팅으로 성형한 다음, 금형에서 성형물을 취출하여 약 20℃ 내지 30℃의 온도로 냉각함으로써 제조가 완료된다. 이때, 금형에서 취출된 성형물은 수냉식으로 냉각할 경우 주철재 베어링 인서트(10)가 발청되어 부식되므로 반드시 상온에서 공냉식으로 냉각해야 한다. 따라서, 크랭크 케이스(1)는 전술한 다이캐스팅 및 공냉식 냉각에 의해 주철재 베어링 인서트(10) 및 알루미늄재가 복합된 하이브리드 형태의 제품으로 제조된다.In more detail, in order to manufacture the crankcase 1 shown in FIG. 1, the cast iron bearing insert 10 is preheated to a temperature of about 200 ° C. or more, charged into a mold, and then melted at about 650 ° C. Manufacturing is completed by injection molding the metal into the mold cavity by injection molding at a high speed of about 40 m / s and a high pressure of about 500-1000 bar, and then taking out the molding from the mold and cooling it to a temperature of about 20 to 30 ℃. do. At this time, the molded product taken out from the mold is cooled by water cooling, so cast iron bearing insert 10 is corroded and must be cooled by air cooling at room temperature. Therefore, the crankcase 1 is manufactured as a hybrid type product in which the cast iron bearing insert 10 and the aluminum material are combined by the above-mentioned die casting and air cooling.
이러한 크랭크 케이스(1)는 전술한 바와 같이 주철재 베어링 인서트(10)가 예열된 상태로 금형의 내부에서 알루미늄 용융금속과 접합되므로 주철 및 알루미늄 간의 밀착성이 우수하고, 특히 고압성형에 의한 다이캐스팅의 특성으로 인하여 치수 정밀성 및 성형상의 재현성이 매우 우수할 뿐만 아니라 조직이 매우 치밀하다.As described above, the crank case 1 is bonded to the molten aluminum metal in the mold in a state in which the cast iron bearing insert 10 is preheated, so that the crank case 1 has excellent adhesion between cast iron and aluminum, and particularly, die casting characteristics due to high pressure molding. Due to this, not only the dimensional accuracy and the reproducibility of the molding are excellent but also the structure is very dense.
다른 한편, 전술한 바와 같이 알루미늄 베어링 인서트가 적용된 모노 크랭크 케이스(Mono crank case)의 경우, 전술한 바와 같이 주철재 베어링 인서트(10)로 크랭크 케이스(1)를 제조하는 하이브리드 다이캐스팅 방식을 적용할 것으로 예상된다.On the other hand, as described above, in the case of the mono crank case to which the aluminum bearing insert is applied, the hybrid die casting method of manufacturing the crank case 1 from the cast iron bearing insert 10 will be applied. It is expected.
하지만, 이러한 모노 크랭크 케이스는 주철재 베어링 인서트(10)와 달리 약 200℃ 이상의 온도에서 풀림이 발생하여 강도가 급격히 저하되는 알루미늄의 특성으로 인해 전술한 주철재 베어링 인서트(10)로 크랭크 케이스(1)를 제조하는 방법의 적용이 적합하지 않다. 즉, 모노 크랭크 케이스는 알루미늄 베어링 인서트의 재질 특성으로 인하여 전술한 방법으로 제조할 경우 물성저하(강도저하)가 발생할 수 있다.However, unlike the cast iron bearing insert 10, the mono crank case is a cast iron bearing insert 10 as described above due to the characteristics of aluminum, which causes a sharp drop in strength due to annealing at a temperature of about 200 ° C. or more. The application of the method of making) is not suitable. That is, the mono crank case may have a decrease in physical properties (decrease in strength) when manufactured by the above-described method due to the material properties of the aluminum bearing insert.
이를 좀더 자세히 설명하면, 모노 크랭크 케이스는 전술한 하이브리드 다이캐스팅으로 제조될 경우, 'M'형의 알루미늄 베어링 인서트를 주철 인서트와 같이 예열하여 다이캐스팅 금형에 장입한 후, 약 650℃의 알루미늄 용융금속을 다이캐스팅 금형의 캐비티에 주입하여 응고시킨 다음 취출하여 공냉식으로 자연 냉각시키면, 예열 상태로 고온의 알루미늄 용융금속에 접합되는 알루미늄 베어링 인서트가 알루미늄 용융금속에 의해 약 500℃ 이상 급속히 가열될 뿐만 아니라 냉각을 위해 상온에서 장시간 동안 약 200℃ 이상의 온도(약 400-450℃)로 방치되므로 주철 보다 낮은 약 550-600℃의 융점을 갖는 알루미늄합금의 특성으로 인해 거의 용융에 가까운 고온상태로 장시간 방치됨에 따라 기계적 성질이 급격히 저하되며, 장시간의 공냉 시간으로 인해 성형 사이클 시간이 증가하여 생산성이 낮아지는 문제가 있다.To explain this in more detail, when the mono crank case is manufactured by the above-mentioned hybrid die casting, the aluminum bearing insert of the 'M' type is preheated like a cast iron insert, charged into a die casting mold, and then die cast aluminum molten metal at about 650 ° C. When injected into the cavity of the mold to be solidified, taken out, and naturally cooled by air cooling, the aluminum bearing insert, which is joined to the hot aluminum molten metal in a preheated state, is not only rapidly heated by the aluminum molten metal to about 500 ° C. or more, but also cooled to room temperature Because it is left at a temperature of about 200 ℃ or more (about 400-450 ℃) for a long time at, the mechanical properties of the aluminum alloy have a melting point of about 550-600 ℃ lower than that of cast iron. Rapidly deteriorates, due to long air cooling time There is a problem that productivity is lowered due to increased cycle time.
따라서, 본 발명의 출원인은 전술한 바와 같이 하이브리드 다이캐스팅 방법이 오로지 단순한 접합성만 충족시키고 있을 정도이고, 인서트의 재질에 따른 제조공법의 변경과 개선을 이루지 못하고 있기에 이를 개선하고자 장기간 연구 및 실험하여 본 발명을 출원하게 되었다.Therefore, the applicant of the present invention, as described above, the hybrid die casting method is only to satisfy only simple bonding, and does not achieve the change and improvement of the manufacturing method according to the material of the insert, the present invention by long-term research and experiment to improve this To apply for.
본 발명은 상기와 같은 문제점을 해결하기 위한 것으로, 주조에 의해 일체화된 하이브리드 다이캐스팅에서 알루미늄 베어링 인서트의 기계적 성질이 감소되는 것을 최소화하면서 다이캐스팅의 성형 사이클 시간을 단축하여 생산성을 향상시킬 수 있는 하이브리드 다이캐스팅에 의한 엔진용 로우 크랭크 케이스의 제조방법을 제공하는데 그 목적이 있다.The present invention is to solve the above problems, in a hybrid die casting that can improve productivity by shortening the molding cycle time of the die casting while minimizing the reduction of mechanical properties of the aluminum bearing insert in the hybrid die casting integrated by casting It is an object of the present invention to provide a method for manufacturing a low crank case for an engine.
상기와 같은 목적을 달성하기 위한 본 발명은, 엔진의 하부를 구성하는 로우 크랭크 케이스에 크랭크 축을 지지하는 베어링 인서트를 주조로 인서트하여 일체화시키는 하이브리드 다이캐스팅 방식의 제조방법에 있어서, 다이캐스팅 금형의 캐비티에 알루미늄 합금재질의 베어링 인서트를 장입하는 인서트 장입단계; 상기 인서트 장입단계 후 상기 금형 캐비티에 용융금속을 고속 고압으로 사출하여 로우 크랭크 케이스를 성형하는 다이캐스팅단계; 상기 다이캐스팅단계 후 상기 로우 크랭크 케이스를 상기 금형 캐비티에서 취출하는 취출단계; 및 상기 취출단계 후 로우 크랭크 케이스를 급속 냉각하는 냉각단계;를 포함하고, 상기 냉각단계는, 상기 취출된 로우 크랭크 케이스를 수조의 냉각수를 통해 수냉식으로 급속 냉각하는 것을 특징으로 한다.In the present invention for achieving the above object, in the manufacturing method of the hybrid die-casting method of inserting and inserting a bearing insert for supporting the crankshaft by casting into a low crankcase constituting the lower part of the engine, aluminum in the cavity of the die casting mold. Insert charging step of charging the bearing insert of the alloy material; A die casting step of molding a low crank case by injecting molten metal into the mold cavity at a high speed and high pressure after the insert charging step; Taking out the low crank case from the mold cavity after the die casting step; And a cooling step of rapidly cooling the low crank case after the take-out step, wherein the cooling step is characterized in that the low crank case is rapidly cooled by water cooling through a cooling water of a tank.
여기서, 상기 베어링 인서트는 예컨대, 상온의 온도로 다이캐스팅 금형의 캐비티에 장입되는 것이 바람직하다.Here, the bearing insert is preferably inserted into the cavity of the die casting mold, for example at a temperature of room temperature.
상기 냉각단계는 예컨대, 상기 취출된 로우 크랭크 케이스를 냉각수가 저수된 상기 수조에 장입하는 수조 장입단계; 상기 수조에 장입된 상기 로우 크랭크 케이스를 설정된 시간 동안 상기 수조의 냉각수에 침잠시키 침잠단계; 및 상기 수조에서 상기 로우 크랭크 케이스를 인출하는 인출단계;를 포함하여 구성할 수 있다.The cooling step may include, for example, a tank charging step of charging the taken out low crank case into the tank in which cooling water is stored; Immersing the low crank case charged in the tank in the cooling water of the tank for a predetermined time; And a withdrawal step of withdrawing the low crankcase from the water tank.
상기 침잠단계는 예컨대, 상기 로우 크랭크 케이스를 130℃ 내지 190℃까지 냉각시킬 수 있는 적정 시간 동안 상기 수조의 냉각수에 상기 로우 크랭크 케이스를 침잠시키는 것이 바람직하다.In the submerging step, for example, it is preferable to submerge the low crankcase in the cooling water of the water tank for a suitable time to cool the low crankcase to 130 ° C to 190 ° C.
본 발명은, 상기 취출된 로우 크랭크 케이스의 온도에 의해 상기 수조에 저수된 냉각수의 수온이 급격하게 상승하거나 냉각수에서 워터버블이 발생되는 것이 방지되도록, 상기 수조의 냉각수를 순환시키는 냉각수 순환단계;를 더 포함하는 것이 바람직하다.The present invention, the cooling water circulation step of circulating the cooling water of the water tank so that the water temperature of the cooling water stored in the water tank is suddenly increased or the water bubble is not generated in the cooling water by the temperature of the extracted low crank case; It is preferable to further include.
상기 냉각수 순환단계는 예컨대, 상기 수조에 저수된 냉각수의 일부가 교환되면서 냉각수가 순환되도록, 상기 수조의 냉각수 중 일부의 냉각수를 상기 수조의 외부로 배출하면서 배출된 냉각수의 양에 대응하는 새로운 냉각수를 상기 수조에 보충하는 냉각수 교환단계;로 구성할 수 있다.The cooling water circulation step may include, for example, a new cooling water corresponding to the amount of cooling water discharged while discharging the cooling water of a portion of the cooling water of the tank to the outside of the tank so that the cooling water is circulated while exchanging a portion of the cooling water stored in the tank. Cooling water exchange step to replenish the tank; can be configured.
상기 냉각수 순환단계는, 상기 수조의 내부에 교반 날개가 마련되어 냉각수를 교반시켜 상기 수조에서 냉각수를 순환시키는 교반단계;로 구성할 수도 있다.The cooling water circulation step, the stirring blade is provided in the inside of the water tank to agitate the cooling water to circulate the cooling water in the water tank; may be configured as.
본 발명은, 상기 수조에 장입된 상기 로우 크랭크 케이스나 상기 로우 크랭크 케이스를 상기 수조에 장입시키는 엘리베이터 중 적어도 어느 하나를 진동시켜서 냉각수와 로우 크랭크 케이스의 열교환을 증가시키는 바이브레이션단계;를 더 포함할 필요가 있다.The present invention may further include a vibration step of increasing heat exchange between the coolant and the low crankcase by vibrating at least one of the low crankcase charged in the water tank and an elevator for charging the low crankcase into the water tank. There is.
본 발명은, 상기 수조에서 냉각되어 인출된 상기 로우 크랭크 케이스에서 물기를 제거하는 물기 제거단계;를 더 포함한다.The present invention further includes a water removal step of removing water from the low crank case drawn out by cooling in the water tank.
상기 물기 제거단계는, 상기 수조에서 인출된 상기 로우 크랭크 케이스에서 물기가 건조되어 제거되도록 상기 로우 크랭크 케이스의 물기가 건조되는 시간 동안 상기 로우 크랭크 케이스를 상온에 방치하는 상온 방치단계;로 구성할 수 있다.The water removal step may include: a room temperature standing step of leaving the low crank case at room temperature while the water of the low crank case is dried to remove water from the low crank case drawn out of the water tank. have.
이와 달리, 상기 물기 제거단계는 예컨대, 상기 수조에서 로우 크랭크 케이스를 인출시켜 압축된 공기를 로우 크랭크 케이스의 표면에 분사하여 로우 크랭크 케이스의 표면에서 물기를 제거하는 에어 블로잉단계;로 구성할 수도 있다.Alternatively, the water removing step may include, for example, an air blowing step of removing the water from the surface of the low crankcase by injecting the compressed air into the surface of the low crankcase by drawing the low crankcase from the water tank. .
또, 상기 물기 제거단계는, 상기 에어 블로잉단계 후, 상기 압축된 공기에 의해 물기가 제거된 로우 크랭크 케이스를 자연 건조하는 건조단계;를 더 포함하여 구성할 수도 있다.The water removal step may further include a drying step of naturally drying the low crank case from which water is removed by the compressed air after the air blowing step.
본 발명은, 상기 냉각단계 후, 상기 로우 크랭크 케이스에 형성된 탕구부를 제거하는 트리밍단계;를 더 포함할 수 있다.The present invention may further include a trimming step of removing a hot mouth formed in the low crankcase after the cooling step.
또한, 본 발명은, 상기 냉각단계 후, 상기 로우 크랭크 케이스를 열처리하여 내부 응력을 제거하는 어닐링단계;를 더 포함할 수도 있다.The present invention may further include an annealing step of removing the internal stress by heat treating the low crank case after the cooling step.
본 발명에 따른 하이브리드 다이캐스팅에 의한 엔진용 로우 크랭크 케이스의 제조방법에 의하면, 다이캐스팅 금형에 예열되지 않은 알루미늄재 베어링 인서트를 장입한 후 금형에 알루미늄재 용융금속을 충전하여 로우 크랭크 케이스의 온도가 약 400~450℃일 때 취출한 다음, 로우 크랭크 케이스를 급속하게 냉각시키므로 약 200도에 달하는 통상의 예열온도보다 낮은 온도의 베어링 인서트에 의해 용융금속이 신속하게 응고되면서 냉각되어 성형시간을 단축시킬 수 있을 뿐만 아니라 성형온도의 저하에 의해 베어링 인서트가 고온에 노출되는 것을 최소화시킬 수 있으며, 이에 더하여 베어링 인서트가 접합된 로우 크랭크 케이스가 급속냉각되므로 베이링 인서트를 고온에 노출시키는 시간을 대폭적으로 감소시킬 수 있다. 따라서, 베어링 인서트가 열적 스트레스에 의해 물성이 저하되는 것을 방지할 수 있다.According to the method for manufacturing a low crank case for an engine by a hybrid die casting according to the present invention, after charging an aluminum bearing insert which is not preheated to a die casting mold, the molten metal is filled into the mold and the temperature of the low crank case is about 400. After taking out at ~ 450 ℃, the low crankcase is cooled rapidly so that the molten metal can be solidified rapidly and cooled by a bearing insert at a temperature lower than the normal preheating temperature of about 200 degrees, thereby shortening the molding time. In addition, it is possible to minimize the exposure of the bearing insert to high temperatures due to the reduction of the molding temperature. In addition, the low crank case to which the bearing insert is bonded is rapidly cooled, which greatly reduces the time for exposing the bearing insert to high temperature. have. Therefore, the bearing insert can be prevented from deteriorating in physical properties due to thermal stress.
특히, 종래기술에서 적용되던 베어링 인서트의 예열공정을 생략할 수 있으므로 예열시간의 생략으로 인한 전체 생산 공정의 소요시간을 단축할 수 있으므로 생산성을 증가시킬 수 있으며, 로우 크랭크 케이스를 수조의 냉각수에 장입하여 수냉식으로 냉각시키므로 로우 크랭크 케이스를 용이하면서 신속하게 냉각시킬 수 있으며, 이에 따라 로우 크랭크 케이스의 생상성을 향상시킬 수 있다.In particular, the preheating process of the bearing insert used in the prior art can be omitted, which can shorten the time required for the entire production process due to the elimination of the preheating time, thereby increasing productivity, and inserting the low crankcase into the cooling water of the tank. Therefore, since the cooling is performed by water cooling, the low crankcase can be cooled easily and quickly, thereby improving the productivity of the low crankcase.
그리고, 취출된 로우 크랭크 케이스를 설정된 시간 동안 수조의 냉각수에 침잠시켜서 냉각시간을 실질적으로 단축시키므로 로우 크랭크 케이스의 전체적인 생산 사이클을 효율적으로 관리할 수 있으며, 이에 더하여 알루미늄재가 약 200℃ 이상의 온도에서 급격히 연화되어 기계적 성질이 감소되므로 로우 크랭크 케이스를 약 130-190℃의 온도로 수조에서 냉각시킴에 따라 베어링 인서트의 물성저하를 방지할 수 있을 뿐만 아니라 건조 공정을 위한 잠열을 확보할 수 있다. In addition, the low crank case is submerged in the cooling water of the tank for a predetermined time, thereby substantially reducing the cooling time, thereby efficiently managing the entire production cycle of the low crank case, and in addition, the aluminum material rapidly increases at a temperature of about 200 ° C. or more. Since the softening reduces mechanical properties, the low crankcase is cooled in a water bath at a temperature of about 130-190 ° C. to prevent deterioration of the properties of the bearing insert and to secure latent heat for the drying process.
또, 수조의 냉각수를 순환시킬 수 있으므로 수조에 저수된 수온이 상승하는 것을 방지하거나 냉각수에서 워터버블이 발생하는 것을 방지하여 로우 크랭크 케이스를 전체적으로 골고루 냉각시킬 수 있을 뿐만 아니라 로우 크랭크 케이스의 표면에 워터버블의 자국이 발생하는 것을 방지할 수 있고, 이에 더하여 저수된 냉각수의 일부를 배출하면서 배출량에 대응하는 새로운 냉각수를 보충하므로 저수된 냉각수의 수온이 상승하여도 다시 하강시킬 수 있을 뿐만 아니라 냉각수의 수온 하강에 의해 워터버블이 발생하는 것을 방지할 수 있으며, 더 나아가 냉각수를 교반시킬 경우 냉각수의 수온 상승 및 워터버블 현상을 더욱더 방지할 수 있을 뿐만 아니라 로우 크랭크 케이스를 더욱더 골고루 냉각시킬 수 있다.In addition, since the cooling water in the tank can be circulated, the water temperature stored in the tank can be prevented from rising or water bubbles can be generated from the cooling water, thereby not only cooling the low crankcase as a whole, but also water on the surface of the low crankcase. It is possible to prevent the formation of bubbles, and to replenish the new coolant corresponding to the discharge while discharging a part of the stored coolant, so that the stored coolant can be lowered even when the temperature of the stored coolant rises, as well as the coolant water temperature. Water bubbles can be prevented from being lowered, and when the cooling water is stirred, the water temperature rise and the water bubble phenomenon of the cooling water can be further prevented, and the low crankcase can be cooled evenly.
또한, 로우 크랭크 케이스를 수조에 침잠시키는 엘리베이터나 로우 크랭크 케이스를 진동시켜서 냉각수를 유동시키므로 로우 크랭크 케이스를 냉각수와 원활하게 열교환시킬 수 있을 뿐만 아니라 워터버블이 발생되는 것을 방지할 수도 있다. In addition, since the cooling water flows by vibrating the elevator or low crank case submerging the low crank case in the water tank, not only the low crank case can be heat exchanged smoothly with the cooling water, but also water bubbles can be prevented from being generated.
아울러, 수냉식으로 냉각이 완료된 로우 크랭크 케이스에 압축된 공기를 분사하여 로우 크랭크 케이스의 표면에 잔존하는 물기를 제거할 수 있으므로 잔존하는 물기에 의해 로우 크랭크 케이스의 표면이 오염되는 것을 방지할 수 있고, 이에 더하여 로우 크랭크 케이스의 표면에 형성된 중공부나 복잡한 형상 부위에 물이 잔류하는 것을 방지할 수 있으며, 로우 크랭크 케이스의 건조시간을 단축할 수도 있다.In addition, by spraying compressed air to the low crank case is cooled by water-cooling can remove the water remaining on the surface of the low crank case, it is possible to prevent the surface of the low crank case from contamination by the remaining water, In addition, water can be prevented from remaining in the hollow portion or the complicated shape portion formed on the surface of the low crankcase, and the drying time of the low crankcase can be shortened.
게다가, 로우 크랭크 케이스를 방치하여 로우 크랭크 케이스의 잠열을 통해 로우 크랭크 케이스의 물기를 제거하므로 용이하게 건조공정을 수행할 수 있을 분만 아니라 로우 크랭크 케이스를 사실상 완전하게 건조할 수 있다.In addition, the low crank case is left to remove moisture from the low crank case through the latent heat of the low crank case, so that the drying process can be easily performed, and the low crank case can be completely completely dried.
덧붙여, 로우 크랭크 케이스의 탕구부를 트리밍하여 제거하므로 미려한 외관의 로우 크랭크 케이스를 제공할 수 있으며, 더욱이 로우 크랭크 케이스를 어닐링 하므로 로우 크랭크 케이스 및 베어링 인서트의 물성을 향상시킬 수 있다.In addition, by trimming and removing the mouth of the low crank case, it is possible to provide a low crank case with a beautiful appearance, and furthermore, by annealing the low crank case, the physical properties of the low crank case and the bearing insert can be improved.
도 1은 종래의 엔진용 로우 크랭크 케이스 및 주철재 베어링 인서트를 도시한 사시도이다.1 is a perspective view showing a low crank case and a cast iron bearing insert for a conventional engine.
도 2는 경량화 인서트식 엔진용 로우 크랭크 케이스 및 알루미늄 베어링 인서트를 도시한 사시도이다.2 is a perspective view showing a low crank case and an aluminum bearing insert for a lightweight insert engine.
도 3은 본 발명의 실시예의 의한 하이브리드 다이캐스팅 방식의 엔진용 로우 크랭크 케이스의 제조방법을 나타낸 순서도이다.3 is a flowchart illustrating a method of manufacturing a low crank case for a hybrid die casting engine according to an embodiment of the present invention.
도 4는 본 발명의 실시예의 의한 제조방법 중 냉각단계를 도시한 개략도이다.Figure 4 is a schematic diagram showing a cooling step of the manufacturing method according to an embodiment of the present invention.
도 5는 본 발명의 실시예의 의한 제조방법 중 에어 블로잉단계를 도시한 개략도이다.Figure 5 is a schematic diagram showing an air blowing step of the manufacturing method according to an embodiment of the present invention.
도 6은 본 발명의 실시예의 의해 제조된 엔진용 로우 크랭크 케이스의 알루미늄 인서트의 물성을 다른 예와 비교한 물성표이다.6 is a physical property table comparing the physical properties of the aluminum insert of the engine low crank case manufactured by the embodiment of the present invention.
본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니 되며, 발명자는 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다.The terms or words used in this specification and claims are not to be construed as being limited to the common or dictionary meanings, and the inventors can appropriately define the concept of terms in order to explain their invention in the best way. Based on the principle, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.
이하, 첨부된 도면을 참조하여 본 발명의 바람직한 실시예를 상세히 설명하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
본 발명의 실시예에 의한 하이브리드 다이캐스팅 방식의 엔진용 로우 크랭크 케이스 제조방법은, 도 3에 도시된 바와 같이 인서트 장입단계(S10), 다이캐스팅단계(S20), 취출단계(S30), 냉각단계(S40)의 순으로 이루어진다.Hybrid cranking engine low crank case manufacturing method according to an embodiment of the present invention, insert charging step (S10), die casting step (S20), take-out step (S30), cooling step (S40) as shown in FIG. ) In that order.
즉, 본 발명은 엔진의 하부를 구성하는 로우 크랭크 케이스에 크랭크 축을 지지하는 베어링 인서트를 주조로 인서트하여 일체화시키는 제조방법에 관한 것으로, 먼저 종래기술에서 설명된 바와 같은 베어링 인서트를 성형한다.That is, the present invention relates to a manufacturing method for inserting and inserting a bearing insert for supporting a crankshaft by casting into a low crankcase constituting a lower part of an engine. First, a bearing insert as described in the prior art is molded.
이를 위해, 10 ~ 13 wt% 실리콘(Si), 3 ~ 6 wt% 구리(Cu), 0.3 ~ 1.0 wt% 마그네슘(Mg) 및 잔량의 알루미늄(Al)으로 구성된 알루미늄 합금 조성물을 열간단조하여 알루미늄 합금으로 이루어진 베어링 인서트를 성형하게 된다.To this end, an aluminum alloy is hot-forged by an aluminum alloy composition composed of 10 to 13 wt% silicon (Si), 3 to 6 wt% copper (Cu), 0.3 to 1.0 wt% magnesium (Mg), and a balance of aluminum (Al). To form a bearing insert consisting of.
이때, 베어링 인서트의 물성은 도 6에 나타난 바와 같이, 기계적 성질은 경도 HRB 80~85 , 인장강도 400~450 MPa , 항복강도 350~380 Mpa 이다.At this time, the physical properties of the bearing insert, as shown in Figure 6, the mechanical properties are hardness HRB 80 ~ 85, tensile strength 400 ~ 450 MPa, yield strength 350 ~ 380 Mpa.
상기와 같이 베어링 인서트가 성형되면, 이를 로우 크랭크 케이스를 성형하기 위한 다이캐스팅 금형의 캐비티에 장입시키는 인서트 장입단계(S10)가 실시되는데, 이때 다이캐스팅 금형의 캐비티에 장입되는 베어링 인서트는 일반적인 방식과 달리 고온으로 예열되지 않고 금형에 장입되며, 베어링 인서트의 장입을 위해 로봇이 사용될 수 있다.When the bearing insert is molded as described above, an insert charging step (S10) of inserting it into the cavity of the die casting mold for forming the low crankcase is performed, wherein the bearing insert charged into the cavity of the die casting mold has a high temperature unlike a general method. It is loaded into the mold without preheating, and the robot can be used to load the bearing inserts.
여기서, 전술한 베어링 인서트는 약 10℃ 내지 50℃의 온도로 장입될 수 있으나, 상온의 온도(약 15℃~35℃)로 장입되는 것이 바람직다. 이러한 베어링 인서트는 10℃ 이하로 장입될 경우 후술되는 고온의 알루미늄 용융금속과의 온도차가 너무 심하여 접합성이 저하될 수 있고, 50℃ 이상의 온도로 장입될 경우 용융금속과의 온도차가 작아져서 기대하는 응고(성형시간)을 도모할 수 없다.Here, the above-mentioned bearing insert may be charged at a temperature of about 10 ° C to 50 ° C, but is preferably loaded at a room temperature (about 15 ° C to 35 ° C). When the bearing insert is loaded at 10 ° C. or less, the difference in temperature with the high temperature molten aluminum metal described later may be so severe that the bonding property may be degraded. (Molding time) cannot be planned.
상기와 같이 인서트 장입단계(S10)가 실시된 후에는 다이캐스팅 금형의 캐비티에 용융금속을 고속 고압으로 사출하여 로우 크랭크 케이스를 성형하는 다이캐스팅단계(S20)가 실시된다.After the insert charging step S10 is performed as described above, a die casting step S20 is performed in which molten metal is injected at a high speed and high pressure into the cavity of the die casting mold to form a low crankcase.
즉, 다이캐스팅단계(S20)는 베어링 인서트를 로봇을 사용하여 정밀하고 신속하게 다이캐스팅 금형의 캐비티에 지정된 위치에 장입시키게 되는데, 베어링 인서트가 다이캐스팅 금형의 캐비티에 장입되기 전에 다이캐스팅 금형의 캐비티를 약 120~250℃로 예열한 후 베어링 인서트를 장입하고 다이캐스팅 금형을 닫아 폐쇄하게 된다.That is, in the die casting step (S20), the bearing insert is loaded into the cavity of the die casting mold precisely and quickly by using a robot. Before the bearing insert is charged into the cavity of the die casting mold, the cavity of the die casting mold is about 120 ~ After preheating to 250 ° C, the bearing insert is charged and the die casting mold is closed to close.
그리고, 다이캐스팅 금형의 캐비티에 용융금속을 탕구속도 40 m/s 이상, 가압력 800 bar로 주입하여 0.1 sec 내로 캐비티를 채우게 된다. 이때, 용융금속은 알루미늄 내지 알루미늄 합금 조성물이 될 수 있으며, 용융금속의 온도는 약 650℃ 이다.Then, the molten metal is injected into the cavity of the die casting mold at a pouring speed of 40 m / s or more and a pressing force of 800 bar to fill the cavity within 0.1 sec. At this time, the molten metal may be an aluminum to aluminum alloy composition, the temperature of the molten metal is about 650 ℃.
이와 같이, 다이캐스팅 금형의 캐비티에 용융금속이 주입되면 다이캐스팅의 금형과 베어링 인서트는 각각 용융금속과 접촉하여 용융금속의 열을 흡수하여 용융금속은 다이캐스팅 금형의 캐비티 형상과 부합하는 형태로 응고된다.As such, when molten metal is injected into the cavity of the die casting mold, the die and the mold insert of the die casting respectively come into contact with the molten metal to absorb the heat of the molten metal so that the molten metal solidifies into a shape corresponding to the cavity shape of the die casting mold.
이러한 응고과정에서 다이캐스팅 금형과 용융금속의 온도차는 대략 450℃이고, 베어링 인서트와 용융금속의 온도차는 대략 630℃ 이므로, 베어링 인서트 부근의 열이동이 신속하게 이루어지면서 냉각이 가속됨에 따라 다이캐스팅 금형의 캐비티에 주입된 용융금속의 응고 시간, 즉 로우 크랭크 케이스로 성형되는 시간이 베어링 인서트의 예열시 보다 약 10% 정도 단축된다. 이때, 베어링 인서트는 용융금속에 의한 열적 스트레스가 감소된다. 왜냐하며, 베어링 인서트는 예열되지 않은 상온의 온도로 금형에 장입됨에 따라 용융금속과의 온도차가 예열시보다 크고, 상온의 온도이므로 용융금속에 의해 가열이 촉진되지 않고 서서히 가열될 뿐만 아니라 가열되어도 예열된 상태보다 낮은 온도로 가열되기 때문에 열적 스트레스가 예열시 보다 감소된다. 따라서, 베어링 인서트는 용융금속의 고열에 의한 물성변화, 즉 풀림에 의한 강도저하가 최대한 억제된다. 특히, 베어링 인서트는 전술한 바와 같이 용융금속의 응고 시간이 단축되어 고열에 노출되거나 고열에 의해 가열되는 시간이 최소화되므로 강도저하가 최대한 억제된다.In this solidification process, the temperature difference between the die casting mold and the molten metal is about 450 ° C, and the temperature difference between the bearing insert and the molten metal is about 630 ° C. As the heat is moved around the bearing insert quickly, the cooling is accelerated and the cavity of the die casting mold is accelerated. The solidification time of the molten metal injected into the mold, i.e., the time of forming into the low crankcase, is reduced by about 10% compared to preheating the bearing insert. At this time, the bearing insert is reduced thermal stress caused by the molten metal. Because the bearing insert is charged into the mold at a temperature of room temperature, which is not preheated, the temperature difference with the molten metal is greater than that of the preheating, and the temperature of the room temperature is room temperature. Thermal stress is reduced when preheated because it is heated to a lower temperature than in the preheated state. Therefore, the bearing insert is suppressed as much as possible due to the change in physical properties of the molten metal due to the high heat, that is, the decrease in strength due to loosening. In particular, the bearing insert is shortened the solidification time of the molten metal as described above to minimize the time to be exposed to high heat or heated by high heat, thereby reducing the strength decrease as much as possible.
한편, 상기와 같은 다이캐스팅단계(S20)가 완료된 후에는 다이캐스팅 금형의 캐비티로부터 취출하는 취출단계(S30)가 실시된다. 취출단계(S30)는 로봇을 이용하여 다이캐스팅 금형의 캐비티에서 응고된 로우 크랭크 케이스를 취출하게 된다.On the other hand, after the die casting step (S20) as described above is completed, taking out step (S30) for taking out from the cavity of the die casting mold. Taking out step (S30) is to take out the low crank case solidified in the cavity of the die casting mold using a robot.
이때, 다이캐스팅 금형의 캐비티에서 로우 크랭크 케이스를 취출할 때의 온도는 대략 400~450℃가 되도록 함으로써, 취출 시 로우 크랭크 케이스를 다이캐스팅 금형에서 밀어내는 밀핀에 로우 크랭크 케이스의 강도가 낮아서 변형 및 손상되는 것을 방지할 수 있다.At this time, the temperature at the time of taking out the low crankcase from the cavity of the die casting mold is about 400 to 450 ° C., so that the low crankcase is deformed and damaged due to the low strength of the mill crank that pushes the low crankcase out of the die casting mold. Can be prevented.
또한, 로우 크랭크 케이스의 취출 온도가 400~450℃ 보다 낮게 되면 다이캐스팅의 성형 사이클 시간이 증가하여 생산성이 낮아지게 되므로, 다이캐스팅 금형에서 로우 크랭크 케이스의 취출 온도는 400~450℃인 것이 바람직하다.In addition, when the take-out temperature of the low crank case is lower than 400 ~ 450 ℃, the molding cycle time of the die casting is increased to reduce the productivity, it is preferable that the take out temperature of the low crank case in the die casting mold is 400 ~ 450 ℃.
상기와 같은 취출단계(S30)가 완료되면 로우 크랭크 케이스를 냉각시키는 냉각단계(S40)가 실시된다. 냉각단계(S40)는 400~450℃의 온도로 금형에서 취출된 로우 크랭크 케이스가 최대한 신속하게 냉각되어 알루미늄재의 물성 저하가 최대한 억제되도록, 다이캐스팅 금형에서 취출된 로우 크랭크 케이스를 도 4에 도시된 바와 같이 냉각수가 담긴 수조에 장입하여 수냉식으로 급속 냉각한다. 즉, 냉각단계(S40)는 400~450℃의 로우 크랭크 케이스가 최단시간에 알루미늄의 물성 저하가 시작되는 약 200℃ 이하의 온도가 되도록 수냉식으로 급속냉각한다.When the extraction step S30 is completed as described above, a cooling step S40 for cooling the low crankcase is performed. Cooling step (S40) is a low crank case taken out of the die at a temperature of 400 ~ 450 ℃ as quickly as possible to minimize the degradation of the physical properties of the aluminum material, so that the low crank case taken out of the die casting mold as shown in Figure 4 Likewise, it is charged into a water tank containing coolant and rapidly cooled by water cooling. That is, the cooling step (S40) is rapid cooling by water-cooling so that the low crank case of 400 ~ 450 ℃ is a temperature of about 200 ℃ or less at the beginning of the decrease of physical properties of aluminum in the shortest time.
냉각단계(S40)는 예컨대, 취출된 로우 크랭크 케이스를 수조의 냉각수에 장입하는 수조 장입단계; 이러한 수조에 장입된 로우 크랭크 케이스를 설정된 시간 동안 수조의 냉각수에 침잠시키 침잠단계; 및 이러한 수조에서 로우 크랭크 케이스를 인출하는 인출단계;를 포함하여 구성할 수 있다. 즉, 냉각단계(S40)는 수조 장입단계, 침잠단계 및 인출단계로 구성할 수 있다.The cooling step S40 may include, for example, a tank charging step of charging the extracted low crank case into the cooling water of the tank; Submerging the low crank case charged in the tank to the cooling water of the tank for a predetermined time; And a withdrawal step of withdrawing the low crankcase from such a water tank. That is, the cooling step (S40) may be composed of the tank charging step, the submerging step and the withdrawal step.
수조 장입단계는 취출된 로우 크랭크 케이스를 통상의 로봇과 같은 장치를 통해 수조의 하부로 깊숙이 장입시킨다. 수조는 400~450℃로 취출된 로우 크랭크 케이스가 수조에 장입될 경우 로우 크랭크 케이스의 표면과 접촉하는 냉각수의 온도가 급격히 상승하여 기화되면서 물이 보글보글 끓는 것과 같은 큰 공기방울, 즉 기포와 같은 워터버블이 수조에 형성된다. 이에 따라, 로우 크랭크 케이스는 워터버블에 의해 부분적으로 물과의 접촉이 차단되어 냉각이 지연되고, 특히 성형된 중공부나 복잡한 형상부의 워터버블이 원활하게 배출되지 못하여 특정 부분만 급속히 냉각되고 다른 부분은 서냉되는 불균일 냉각이 심화된다. 이로 인하여, 로우 크랭크 케이스는 부분적으로 큰 냉각차가 발생하게 되고, 온도가 균일하지 않아서 열변형 증가, 제품내 잔류 응력 증가, 냉각속도 감소의 문제가 발생한다. 따라서, 수조 장입단계는 냉각수의 급격한 수온 상승 및 워터버블의 발생이 최대한 억제되도록 취출된 로우 크랭크 케이스를 도 4에 도시된 바와 같이 수조의 하부로 깊숙이 장입시킨다.The tank charging step charges the extracted low crank case deeply into the bottom of the tank through a device such as a conventional robot. When the low crank case taken out at 400 ~ 450 ° C is charged into the water tank, the water temperature of the coolant contacting the surface of the low crank case rises rapidly and vaporizes. Water bubbles are formed in the tank. As a result, the low crankcase is partially blocked by the water bubble and the cooling is delayed, and in particular, the water bubble cannot be smoothly discharged because the molded hollow part or the complicated shape part is not smoothly discharged, and only the specific part is rapidly cooled. Non-uniform cooling that is slow cooled is intensified. As a result, the low crankcase partly causes a large cooling difference, and the temperature is not uniform, resulting in an increase in thermal deformation, an increase in residual stress in the product, and a decrease in cooling rate. Therefore, the tank charging step charges the low crank case taken out deeply into the bottom of the tank as shown in FIG. 4 so that the rapid rise in water temperature of the cooling water and the generation of water bubbles are suppressed as much as possible.
침잠단계는 로우 크랭크 케이스를 200도 이하까지, 특히 130도 내지 190도까지 냉각되도록 설정된 시간 동안 수조의 냉각수에 로우 크랭크 케이스를 침잠시킨다. 이때, 전술한 설정된 침잠 시간은 약 15초 내지 32초의 시간이 바람직하며, 특히 약 20초의 시간이 가장 바람직하다. 이러한 침잠 시간은 15초 미만일 경우 로우 크랭크 케이스가 전술한 온도로 냉각되지 못하고, 32초 이상의 경우 제조시간이 과도하게 소요되어 양산 사이클에 지장을 발생시킨다. 따라서, 침잠 시간은 약 15초 내지 32초 이내로 한정될 필요가 있다.The submerging step submerges the low crankcase in the coolant of the tank for a time set to cool the low crankcase to 200 degrees or less, in particular 130 degrees to 190 degrees. At this time, the above-described settle time is preferably about 15 seconds to 32 seconds, and most preferably about 20 seconds. If the submersion time is less than 15 seconds, the low crankcase is not cooled to the above-mentioned temperature, and if more than 32 seconds, the manufacturing time is excessively excessive, causing a disruption in the mass production cycle. Therefore, the sleep time needs to be limited to within about 15 seconds to 32 seconds.
특히, 침잠 시간은 본 발명의 출원인이 실험한 바에 의하면 약 20초가 가장 적당하다. 왜냐하면, 설정된 침잠 시간은 통상적으로 로우 크랭크 케이스의 양산시간은 60초 내지 90초이고, 작업 로봇이 베어링 인서트를 금형에 장입한 후 취출하여 수조에 장입한 다음 후술되는 트리밍까지의 관련된 작업을 수행하기 위해서는 약 20초가 가장 적합하기 때문이다.In particular, the sleep time is most suitable about 20 seconds according to the experiment of the applicant of the present invention. Because, the settled time is typically the mass production time of the low crankcase is 60 seconds to 90 seconds, and the work robot loads the bearing insert into the mold, takes it out, loads it into the water tank, and performs the related work until trimming described later. This is because about 20 seconds is most suitable.
인출단계는 수조에서 전술한 시간 동안 침잠되어 전술한 온도로 냉각된 로우 크랭크 케이스를 수조에서 탈거시킨다. 이때, 로우 크랭크 케이스는 전술한 냉각 시간이 초과되지 않도록 신속하게 수조에서 탈거된다. 이러한 인출단계는 로봇 등의 장치를 이용하는 통상의 방법에 의해 로우 크랭크 케이스를 수조에서 탈거하므로 자세한 설명은 생략한다.The withdrawal step removes from the water tank the low crankcase which was submerged in the water bath for the above-mentioned time and cooled to the above-mentioned temperature. At this time, the low crankcase is quickly removed from the water tank so that the aforementioned cooling time is not exceeded. This withdrawal step is omitted because the low crankcase is removed from the water tank by a conventional method using a device such as a robot.
한편, 수조는 약 20~50℃로 냉각수의 수온이 유지되어야 로우 크랭크 케이스를 냉각시킬 수 있다. 하지만, 수조는 전술한 바와 같이 약 400~450℃의 로우 크랭크 케이스가 장입됨에 따라 냉각수가 가열될 수 있다. 수조는 냉각수가 가열되어 수온이 상승할 경우 로우 크랭크 케이스를 전술한 온도로 신속하게 냉각시키기 어렵다. 또한, 수조는 냉각수가 가열된 상태로 다른 로우 크랭크 케이스가 장입될 경우 전술한 워터버블이 더 많이 발생될 수도 있다. 따라서, 수조(20)는 도 4에 도시된 바와 같이 하부 깊숙이 로우 크랭크 케이스(1)가 장입되어 크랭크 케이스(1)가 수온 변화에 영향을 주지 않으면서 워터버블을 발생시키지 않도록, 로우 크랭크 케이스(1)의 높이보다 적어도 3배 이상의 깊이로 제조되고, 후술되는 냉각수 순환단계에 의해 냉각수가 순환되는 것이 바람직하다.Meanwhile, the water tank may cool the low crankcase only when the water temperature of the coolant is maintained at about 20 to 50 ° C. However, the bath may be heated as the low crank case of about 400 ~ 450 ℃ is charged as described above. The water tank is difficult to rapidly cool the low crankcase to the above-mentioned temperature when the coolant is heated and the water temperature rises. In addition, the water tank may generate more water bubbles as described above when another low crank case is charged while the cooling water is heated. Accordingly, the water tank 20 is a low crank case (see Fig. 4) so that the low crank case 1 is charged deeply so that the crank case 1 does not generate water bubbles without affecting the water temperature change. It is preferably manufactured to a depth of at least three times or more than the height of 1), the cooling water is circulated by the cooling water circulation step described later.
수조(20)는 예컨대, 장입된 로우 크랭크 케이스(1)에 의해 냉각수의 수온이 급격히 상승되지 않으면서 로우 크랭크 케이스(1)를 충분히 냉각시킬 수 있도록 약 0.8톤 내지 2.5톤의 냉각수가 저수될 수 있는 크기로 형성된다. 이를 위해, 수조(20)는 약 1.5m 내지 2.5m의 가로 폭 및 세로 폭과 약 1.5m 내지 2m의 깊이를 갖도록 구성된다.The water tank 20 may store, for example, about 0.8 to 2.5 tons of coolant to sufficiently cool the low crankcase 1 without the water temperature of the coolant rapidly increasing by the charged low crankcase 1. It is formed to a size. To this end, the water tank 20 is configured to have a width and length of about 1.5m to 2.5m and a depth of about 1.5m to 2m.
냉각수 순환단계는 수조(20)에 저수된 냉각수를 순환시켜서 냉각수의 수온 상승을 억제할 뿐만 아니라 냉각수에서 워터버블이 발생하는 것을 최대한 억제시킨다. 이러한 냉각수 순환단계는 냉각수 교환단계 및/또는 냉각수 교반단계 중 적어도 어느 하나로 구성할 수 있다.The cooling water circulation step circulates the cooling water stored in the water tank 20 to not only suppress the rise of the water temperature of the cooling water but also suppress the occurrence of water bubbles in the cooling water to the maximum. This cooling water circulation step may be configured as at least one of the cooling water exchange step and / or cooling water stirring step.
냉각수 교환단계는 수조(20)에 저수된 냉각수의 일부가 교환되면서 냉각수가 순환되도록, 수조(20)의 냉각수 중 일부의 냉각수를 수조(20)의 외부로 배출하고, 이와 동시에 배출된 냉각수의 양에 대응하는 새로운 냉각수를 수조(20)에 보충한다. 이를 위해, 수조(20)는 도 4에 도시된 바와 같이 로우 크랭크 케이스(1)에 인접하게 급수관(20a)이 설치되고, 급수관(20a)과 대향하도록 배수관(20b)이 설치된다. 수조(20)는 배수관(20b)을 통해 저수된 냉각수의 일부가 배출되고, 급수관(20a)을 통해 새로운 냉각수가 보충됨에 따라 저수된 냉각수가 순환된다. 이때, 수조(20)는 급수관(20a)을 통해 공급되는 냉각수가 로우 크랭크 케이스(1)와 열교환 후에 배수관(20b)을 통해 배출되므로 냉각수의 온도가 로우 크랭크 케이스(1)에 의해 사실상 상승되지 않을 뿐만 아니라 로우 크랭크 케이스(1)가 신속하게 냉각된다. In the cooling water exchange step, some of the cooling water of the cooling water of the water tank 20 is discharged to the outside of the water tank 20 so that a portion of the cooling water stored in the water tank 20 is circulated, and at the same time, the amount of cooling water discharged. Refill the water tank 20 with a new coolant. To this end, the water tank 20 is provided with a water supply pipe 20a adjacent to the low crank case 1 as shown in FIG. 4, and a drain pipe 20b is installed to face the water supply pipe 20a. A portion of the coolant stored in the water tank 20 is discharged through the drain pipe 20b, and the stored coolant is circulated as new coolant is replenished through the water supply pipe 20a. At this time, since the coolant supplied through the water supply pipe 20a is discharged through the drain pipe 20b after heat exchange with the low crank case 1, the temperature of the coolant may not be substantially raised by the low crank case 1. In addition, the low crankcase 1 is cooled quickly.
본 발명의 출원인이 실험한 바에 따르면, 전술한 바와 같이 냉각수를 교환할 경우 수조(20)는 전술한 냉각수의 공급 및 배출 양에 따라 냉각수의 수온이 최소 약 1℃ 내지 최대 약 12℃ 정도만 상승하고, 특별한 경우(예: 여름철과 폭염으로 실온이 높을 경우)가 아니면 대부분 1℃ 내지 3℃ 이내로만 수온이 상승하여 로우 크랭크 케이스(1)의 냉각에 큰 영향을 주지 못하였다. 따라서, 수조(20)는 급수관(20a)을 통해 냉각수가 공급되어 소망하는 온도로 냉각수의 수온이 유지됨에 따라 로우 크랭크 케이스(1)를 신속하게 전술한 약 130℃ 내지 190℃의 냉각 온도로 냉각시킬 수 있었다. 물론, 수조(20)는 전술한 바와 같이 냉각수의 수온이 약 1℃ 내지 약 12℃ 정도까지만 상승할 수 있는 양의 냉각수가 공급 및 배출되도록 구성되어야 함은 자명하다. According to the experiment of the applicant of the present invention, when the cooling water is exchanged as described above, the water tank 20 increases only the water temperature of the cooling water by about 1 ° C. to about 12 ° C. according to the amount of supply and discharge of the cooling water described above. In most cases, the temperature of the water was raised only within 1 ° C to 3 ° C, except in special cases (eg, when the temperature was high due to the summer season and heat waves), which did not significantly affect the cooling of the low crankcase 1. Therefore, the water tank 20 cools the low crankcase 1 to the above-mentioned cooling temperature of about 130 ° C to 190 ° C as cooling water is supplied through the water supply pipe 20a to maintain the water temperature of the cooling water at a desired temperature. I could make it. Of course, it is obvious that the water tank 20 should be configured to supply and discharge the cooling water in an amount such that the temperature of the cooling water can only rise to about 1 ° C to about 12 ° C.
이러한 수조(20)는 고온의 로우 크랭크 케이스(1)가 장입되므로 약 20-50℃의 냉각수 수온이 어쩔 수 없이 약 1℃ 정도로 상승하지만, 약 20-50℃의 냉각수 수온이 약 12℃ 이상으로 상승할 경우 전술한 로우 크랭크 케이스(1)의 설정된 냉각시간을 초과하여 냉각사이클에 영향이 발생한다. 따라서, 수조(20)는 전술한 바와 같이 약 20-50℃의 냉각수 수온이 약 1℃ 내지 약 12℃까지만 상승하도록 냉각수가 공급 및 배출되어야 한다.Since the high temperature low crankcase 1 is charged in such a water tank 20, the cooling water temperature of about 20-50 ° C. is forced to rise to about 1 ° C., but the cooling water temperature of about 20-50 ° C. is about 12 ° C. or more. When rising, the cooling cycle exceeds the set cooling time of the low crank case 1 described above. Therefore, the water tank 20 should be supplied and discharged so that the cooling water temperature of about 20-50 ° C rises only from about 1 ° C to about 12 ° C as described above.
여기서, 전술한 냉각 온도에 대해 설명하면, 로우 크랭크 케이스(1)는 약 200℃ 이상으로 냉각될 경우 알루미늄재의 특성상 물성변화(연화 작용)가 발생할 위험이 있기 때문에 200℃ 이하로 냉각되어야 하고, 190℃ 이상 및 200℃ 미만으로 냉각될 경우 200℃에 근접하므로 물성변화를 확실히 방지하기 위해서는 전술한 바와 같이 190℃ 이하로 냉각시키는 것이 바람직하다.Here, when the cooling temperature described above is described, the low crankcase 1 should be cooled to 200 ° C. or lower because there is a risk of property change (softening effect) due to the characteristics of the aluminum material when cooled to about 200 ° C. or higher. 190 When the temperature is lower than 200 ° C. and lower than 200 ° C., the temperature is close to 200 ° C., and thus the cooling to 190 ° C. or lower is preferable as described above in order to reliably prevent a change in physical properties.
그리고, 로우 크랭크 케이스는 130℃ 이하로 냉각될 경우 후술되는 자연 건조시 건조시간이 너무 과도하게 소요된다. 좀더 상세하게 설명하면, 로우 크랭크 케이스는 후술되는 자연 건조시 자체의 열, 즉 잠열을 통해 물기를 증발시켜서 제거한다. 하지만, 로우 크랭크 케이스는 130℃ 이하로 냉각될 경우 잠열이 미약하여 물기를 원활하게 증발시킬 수 없을 뿐만 아니라 후술되는 에어 블로잉(Air blowing)으로 잔류된 물기를 제거하기 어렵다. 따라서, 로우 크랭크 케이스는 130℃ 이상의 온도로 냉각되는 것이 바람직하다.In addition, the low crankcase takes too much drying time during natural drying described below when cooled to 130 ° C. or less. In more detail, the low crankcase is removed by evaporating water through its own heat, that is, latent heat, during natural drying, which will be described later. However, when the low crankcase is cooled to 130 ° C. or lower, the latent heat is weak, so that the water cannot be evaporated smoothly, and it is difficult to remove residual water by air blowing described below. Therefore, the low crankcase is preferably cooled to a temperature of 130 ° C or higher.
한편, 전술한 냉각수 교반단계는 도 4에 도시된 바와 같이 수조(20)의 내부에 마련된 교반 날개(23)를 통해 냉각수를 교반시키면서 순환시킨다. 이를 위해, 수조(20)는 도시된 바와 같이 냉각수에 침잠된 로우 크랭크 케이스(1)와 인접하게 교반 날개(23)가 구비된다. 교반 날개(23)는 회전하면서 냉각수를 회류시켜서 냉각수를 활발히 대류시킨다. 따라서, 수조(20)는 냉각수의 수온 상승이 방지될 뿐만 아니라 로우 크랭크 케이스(1)를 더욱 신속하게 냉각시킬 수 있다.On the other hand, the cooling water stirring step described above is circulated while stirring the cooling water through the stirring blade 23 provided in the interior of the water tank 20 as shown in FIG. To this end, the water tank 20 is provided with stirring blades 23 adjacent to the low crank case 1 submerged in the cooling water as shown. The stirring vane 23 rotates the cooling water while rotating, thereby actively condensing the cooling water. Therefore, the water tank 20 can not only prevent the temperature rise of the coolant but also cool the low crankcase 1 more quickly.
여기서, 전술한 로우 크랭크 케이스(1)는 수조(20)에 신속하게 안정적으로 침잠되도록 도 4에 도시된 바와 같이 엘리베이터(21)를 통해 수조(20)에 침잠된다. 이러한 엘리베이터(21)는 통상의 로봇을 통해 금형에서 취출된 로우 크랭크 케이스(1)가 안치된다.Here, the low crank case 1 is immersed in the water tank 20 through the elevator 21 as shown in FIG. 4 so as to quickly and stably immersed in the water tank 20. Such an elevator 21 has a low crank case 1 settled out of a mold through a normal robot.
로우 크랭크 케이스(1)는 수조(20)에 침잠되어 원활하게 열교환되면서 워터버블의 발생이 방지되도록 바이브레이션 단계(S41)를 통해 진동될 수 있다. 이러한 바이브레이션 단계(S41)는 도 4에 도시된 진동장치(22)를 통해 로우 크랭크 케이스(1)를 진동시킨다. 진동장치(22)는 로우 크랭크 케이스(1)에 설치되어 로우 크랭크 케이스(1)를 직접적으로 진동시킬 수 있으나, 이와 달리 전술한 엘리베이터(21)에 설치되어 엘리베이터(21)의 진동을 통해 로우 크랭크 케이스(1)를 진동시킬 수도 있다. 따라서, 진동장치(22)는 로우 크랭크 케이스(1)를 진동시켜서 수조(20)의 냉각수를 사실상 진동시키므로 로우 크랭크 케이스(1)를 원활하게 열교환시킬 수 있을 뿐만 아니라 워터버블이 발생되는 것을 방지한다. The low crank case 1 may be vibrated through the vibrating step S41 so as to be submerged in the water tank 20 to prevent heat generation while smoothly exchanging heat. This vibration step S41 vibrates the low crank case 1 through the vibrator 22 shown in FIG. The vibrator 22 may be installed in the low crank case 1 to vibrate the low crank case 1 directly. Alternatively, the vibrator 22 may be installed in the above-described elevator 21 to provide a low crank through the vibration of the elevator 21. The case 1 may also be vibrated. Thus, the vibrator 22 vibrates the coolant of the water tank 20 by vibrating the low crankcase 1, so that the low crankcase 1 can be heat-exchanged smoothly and prevents water bubbles from being generated. .
한편, 본 발명은 냉각단계(S40)가 실시된 후 물기 제거단계, 트리밍단계(S70) 및 어닐링단계(S80) 중 적어도 어느 하나가 실시될 수 있다.Meanwhile, in the present invention, at least one of the water removal step, the trimming step S70 and the annealing step S80 may be performed after the cooling step S40 is performed.
물기 제거단계는 수조(20)에서 탈거되어 인출된 약 130℃ 내지 190℃의 로우 크랭크 케이스(1)에서 물기를 제거하는 공정이다. 물기 제거단계는, 수조(20)에서 인출된 로우 크랭크 케이스(1)에서 물기가 건조되어 제거되도록 로우 크랭크 케이스(1)의 물기가 건조되는 시간 동안 로우 크랭크 케이스(1)를 상온에 방치하는 상온 방치단계로 구성할 수 있다. 즉, 로우 크랭크 케이스(1)는 수냉식 냉각단계 후 공냉식 냉각단계로 다시 냉각될 수 있다. 이러한 상온 방치단계는 로우 크랭크 케이스(1)의 자체 온도에 의해 물기가 자연적으로 증발할 때까지 로우 크랭크 케이스(1)를 상온에 방치하여 건조시킨다. 하지만, 이러한 상온 방치단계는 로우 크랭크 케이스(1)의 표면이 건조되는 물기에 의해 오염될 수 있다. 따라서, 물기 제거단계는 후술되는 에어 블로잉단계(S50) 및 건조단계(S60)로 구성하는 것이 바람직하다. 즉, 수냉식 냉각단계 이후의 추가적인 공냉식 냉각단계는 에어 블로잉단계(S50) 및 건조단계(S60)로 구성할 수도 있다.The water removal step is a process of removing water from the low crank case 1 of about 130 ° C to 190 ° C removed by being removed from the water tank 20. In the step of removing water, the room temperature of the low crank case 1 is allowed to stand at room temperature during the time that the water of the low crank case 1 dries so that water is dried in the low crank case 1 withdrawn from the water tank 20. It can be configured as a neglect step. That is, the low crank case 1 may be cooled again to the air-cooled cooling step after the water-cooled cooling step. In the room temperature leaving step, the low crank case 1 is left to dry at room temperature until the water naturally evaporates by the temperature of the low crank case 1. However, this room temperature leaving step may be contaminated by the moisture that the surface of the low crank case (1) is dried. Therefore, the water removal step is preferably composed of an air blowing step (S50) and drying step (S60) to be described later. That is, the additional air-cooled cooling step after the water-cooled cooling step may be composed of an air blowing step (S50) and a drying step (S60).
에어 블로잉단계(S50)는 도 5에 도시된 바와 같이, 냉각단계(S40)가 완료된 약 130℃ 내지 190℃의 로우 크랭크 케이스(1)를 컨베이어(30)에 안치시켜 이동시키는 중에 블로워(40)를 통해 압축된 공기를 로우 크랭크 케이스(1)의 표면에 분사하여 로우 크랭크 케이스(1)의 표면에서 물기를 제거한다. 따라서, 로우 크랭크 케이스(1)는 물기에 의한 오염이 표면에 발생하지 않을 뿐만 아니라 표면이 건조되면서 냉각된다. 특히, 로우 크랭크 케이스(1)는 표면에 형성된 중공부 또는 복잡한 형상으로 성형된 부위의 물기가 압축된 공기에 의해 비산되면서 제거된다.As shown in FIG. 5, the air blowing step S50 is performed while the low crank case 1 of about 130 ° C. to 190 ° C. where the cooling step S 40 is completed is placed on the conveyor 30 to move the blower 40. The compressed air is sprayed on the surface of the low crank case 1 to remove moisture from the surface of the low crank case 1. Accordingly, the low crank case 1 is cooled as the surface is dried as well as contamination by moisture does not occur on the surface. In particular, the low crank case 1 is removed while the water of the hollow portion formed on the surface or the portion formed into a complicated shape is scattered by the compressed air.
건조단계(S60)는 에어 블로잉단계(S50)가 실시된 후의 공정이다. 건조단계(S60)는 에어 블로잉단계(S50)를 통해 물기가 제거된 로우 크랭크 케이스(1)를 자연 건조한다. 이때, 로우 크랭크 케이스(1)는 표면에 잔류하는 물기가 자체적으로 발산되는 열에 의해 증발된다. 이러한 건조단계(S60)는 대략 30℃ 내지 50℃의 온도까지 로우 크랭크 케이스(1)를 냉각시킨다.The drying step S60 is a process after the air blowing step S50 is performed. In the drying step S60, the low crank case 1 is naturally dried through the air blowing step S50. At this time, the low crank case 1 is evaporated by the heat that the water remaining on the surface itself dissipates. This drying step (S60) cools the low crank case 1 to a temperature of approximately 30 ℃ to 50 ℃.
트리밍단계(S70)는 다이캐스팅단계(S20)에서 형성된 로우 크랭크 케이스(1)의 탕구부(Gate)를 제거하는 것으로, 건조단계(S60)가 완료된 로우 크랭크 케이스는 트리밍 프레스장치로 이송하여 탕구부를 제거하게 된다.Trimming step (S70) is to remove the tang (Gate) of the low crank case 1 formed in the die casting step (S20), the low crank case of the drying step (S60) is completed is transferred to the trimming press device to remove the tanggu Done.
어닐링 단계(S80)는 다이캐스팅 성형시 다소 약화되는 베어링 인서트의 물성을 강화시킬 수 있도록, 냉각된 로우 크랭크 케이스(1)를 열처리하여 로우 크랭크 케이스(1)의 강도를 강화시키는 공정이다. 어닐링 단계(S80)는 수냉식 및/또는 추가적인 공냉식 냉각단계 이후 실시될 수 있으며, 특히 이러한 냉각단계 이후의 트리밍단계가 진행된 다음 실시되는 것이 바람직하다.The annealing step S80 is a process of strengthening the strength of the low crankcase 1 by heat-treating the cooled low crankcase 1 so as to reinforce the physical properties of the bearing insert which is somewhat weakened during die casting molding. The annealing step (S80) may be carried out after the water-cooled and / or additional air-cooled cooling step, particularly preferably after the trimming step after this cooling step is performed.
어닐링 단계(S80)는 로우 크랭크 케이스(1)를 미도시된 어닐링장치로 이송하여 로우 크랭크 케이스(1)를 열처리한다. 이러한 어닐링단계(S80)는 로우 크랭크 케이스(1)를 일정한 온도로 가열한 다음에 천천히 식혀 내부 조직을 고르게 하고 응력(應力)을 제거한다.In the annealing step S80, the low crank case 1 is transferred to an annealing device, not shown, to heat-process the low crank case 1. This annealing step S80 heats the low crank case 1 to a constant temperature and then cools it slowly to even out internal tissues and remove stress.
어닐링단계(S80)는 로우 크랭크 케이스(1)를 200℃의 온도로 2시간 정도 실시하여 냉각단계(S40)에 의한 급속 냉각에 따른 로우 크랭크 케이스(1)의 잔류 응력의 제거와 고온 급냉 후 시효 강화가 작용하여 강도 상승의 효과를 얻게 된다.The annealing step (S80) is carried out after the low crankcase (1) at a temperature of 200 ℃ for about 2 hours to remove the residual stress of the low crankcase (1) due to rapid cooling by the cooling step (S40) and aging after high temperature quenching Reinforcement is applied to obtain the effect of strength increase.
상기와 같은 제조방법에 의해 제조된 엔진용 로우 크랭크 케이스에 구비된 베어링 인서트의 물성을 도 6에 의거하여 설명한다.The physical properties of the bearing insert provided in the low crank case for an engine manufactured by the above manufacturing method will be described based on FIG. 6.
도시된 바와 같이 물성표에 표시된 "다이캐스팅 전소재 인서트"는 열간단조 성형된 알루미늄재 베어링 인서트, 즉 다이캐스팅 금형에 장입되기 전 베어링 인서트의 물성이다. "실시예 인서트"는 본 발명의 제조방법에 의해 로우 크랭크 케이스에 접합된 알루미늄재 베어링 인서트의 물성이다. "비교예 인서트"는 종래기술에서 설명한 바와 같이 알루미늄재 베어링 인서트를 예열하여 다이캐스팅 금형에 장입한 후 다이캐스팅한 다음 공냉식으로 냉각한 알루미늄재 베어링 인서트의 물성이다.As shown, the "die-casting all-material insert" indicated in the property table is the property of the hot-forged aluminum bearing insert, that is, the bearing insert before being charged into the die-casting die. "Example insert" is the physical property of an aluminum bearing insert joined to a low crankcase by the manufacturing method of the present invention. "Comparative Example Insert" is the physical property of an aluminum bearing insert that is pre-heated, charged into a die casting mold, die cast and then cooled by air cooling as described in the prior art.
도 6에 도시된 바와 같이 "다이캐스팅 전소재 인서트"인 경우 경도 80~85 HRB, 인장강도 400~450 MPa, 항복강도 350~380 MPa의 기계적 성질을 갖는다. 그리고, "비교예 인서트"인 경우 경도 50~55 HRB, 인장강도 250~300 MPa, 항복강도 220~250 MPa의 기계적 성질을 갖는다. 반면, 본 발명의 제조방법에 의해 제조된 베어링 인서트는 경도 70~75 HRB, 인장강도 350~380 MPa, 항복강도 3000~330 MPa의 기계적 성질을 갖는다.As shown in Figure 6, the "die-casting all material insert" has a mechanical property of hardness 80 ~ 85 HRB, tensile strength 400 ~ 450 MPa, yield strength 350 ~ 380 MPa. And, "Comparative Example Insert" has a mechanical property of hardness 50 ~ 55 HRB, tensile strength 250 ~ 300 MPa, yield strength 220 ~ 250 MPa. On the other hand, the bearing insert produced by the manufacturing method of the present invention has a mechanical property of hardness 70 ~ 75 HRB, tensile strength 350 ~ 380 MPa, yield strength 3000 ~ 330 MPa.
이러한 결과에 의하면, "비교예 인서트"의 베어링 인서트는 "다이캐스팅 전소재 인서트"와 비교할 때 약 35%의 물성이 감소하지만, 본 발명에 의해 제조된 "실시예 인서트"는 약 13%의 물성이 감소하기 때문에 본 발명에 의해 제조된 베어링 인서트의 품질 한계를 만족하여 제품으로서 기능을 충분히 수행할 수 있는 수준으로 나타났다.According to these results, the bearing insert of the "Comparative insert" has about 35% decrease in physical properties compared to the "die-casting all material insert", but the "Example insert" produced by the present invention has about 13% of the physical property. Since it is reduced, the quality of the bearing insert manufactured according to the present invention is satisfied, and it is shown that the function can be sufficiently performed as a product.
여기서, 전술한 "비교예 인서트"는 알루미늄재 베어링 인서트가 약 200℃의 온도로 예열된 상태에서 용융금속과 접촉하고, 공냉을 위해 약 400℃ 내지 500℃의 온도로 장시간 상온에 방치되어 풀림현상이 발생함에 따라 기계적 물성이 본 발명의 실시예에 의한 "실시예 인서트" 보다 약화되었다고 사료된다. 하지만, 전술한 본 발명의 실시예에 의한 "실시예 인서트"는 예열되지 않은 베어링 인서트에 의해 금형에 주입된 용융금속의 온도가 낮아져서 베어링 인서트가 "비교예 인서트"와 달리 고온에 사실상 노출되지 않았고, 이에 따른 용융금속의 온도저하에 따라 성형시간이 단축되어 베어링 인서트의 고온상태 지속시간이 단축되었으며, 수냉식 냉각에 의해 고온상태의 유지시간이 대폭적으로 단축됨에 따라 풀림이 억제되어 물성 저하가 방지되었다.Here, the "comparative example insert" described above is in contact with the molten metal while the aluminum bearing insert is preheated to a temperature of about 200 ° C., and left at room temperature for a long time at a temperature of about 400 ° C. to 500 ° C. for air cooling. As this occurs, it is believed that the mechanical properties are weaker than the "Example insert" according to the embodiment of the present invention. However, the "embodiment insert" according to the embodiment of the present invention described above has lowered the temperature of the molten metal injected into the mold by the unpreheated bearing insert, so that the bearing insert is not substantially exposed to high temperature unlike the "comparative insert". As a result, the molding time is shortened according to the temperature decrease of the molten metal, and the duration of the high temperature state of the bearing insert is shortened. .
한편, 도시된 물성표에는 표기하지 않았으나, 알루미늄재 베어링 인서트를 예열하지 않고, 본 발명의 실시예와 같이 상온의 온도로 금형에 장입하여 전술한 바와 같이 용융금속으로 금형에서 성형한 후 수냉식이 아닌 공냉식으로 서냉시킨 로우 크랭크 케이스의 경우에도 전술한 "비교예 인서트"와 거의 대동소이한 특성을 보이기에 물성표에 기재하지 않았다. 따라서, 본 발명의 실시예와 동일하게 성형한 후 공냉식으로 서냉시킨 로우 크랭크 케이스도 기계적 물성이 본 발명에 의한 "실시예 인서트"보다 약화되었다. 이는, 로우 크랭크 케이스가 알루미늄 합금의 융점에 가까운 온도로 장시간 동안 상온에 방치됨에 따라 풀림현상에 의해 물성 저하가 발생한 것으로 사료된다.On the other hand, although not shown in the physical properties shown, the aluminum bearing insert is not preheated, and charged into the mold at a temperature of room temperature as in the embodiment of the present invention and then molded in the mold with molten metal as described above, not water-cooled In the case of the low-crank case, which was cooled by slow cooling, the characteristics were almost similar to those of the "Comparative Example insert" described above. Accordingly, the low crank case molded in the same manner as in the embodiment of the present invention and then cooled by air cooling was weaker in mechanical properties than the "example insert" according to the present invention. It is considered that the lower crank case is left at room temperature for a long time at a temperature close to the melting point of the aluminum alloy, thereby deteriorating physical properties due to the unwinding phenomenon.
상기와 같은 본 발명에 따른 엔진용 로우 크랭크 케이스의 제조방법에 의하면, 다이캐스팅 금형에서 로우 크랭크 케이스의 온도가 400~450℃일 때 취출하고, 이를 수조의 냉각수에 장입하여 급속 냉각시켜 로우 크랭크 케이스의 온도가 150℃일 때 인출시키기 때문에 다이캐스팅의 성형 사이클 시간을 단축하여 생산성을 향상시킬 수 있다.According to the method for manufacturing an engine low crank case according to the present invention as described above, the temperature of the low crank case in the die casting mold is taken out when the temperature of 400 ~ 450 ℃, charged into the cooling water of the tank to rapidly cool the low crank case Since the drawing is carried out when the temperature is 150 ° C., the molding cycle time of die casting can be shortened to improve productivity.
또한, 본 발명은 냉각단계에서 로우 크랭크 케이스의 온도가 150℃일 때 수조에서 인출하기 때문에 베어링 인서트가 연화하는 것을 방지할 수 있을 뿐만 아니라 로우 크랭크 케이스가 갖는 잠열에 의해 물기를 증발시킬 수 있어 로우 크랭크 케이스의 표면에 오염이 발생하는 것을 방지할 수 있다.In addition, in the present invention, since the low crankcase is withdrawn from the water tank when the temperature of the low crankcase is 150 ° C, the bearing insert may not be softened, and water may be evaporated by latent heat of the low crankcase. It is possible to prevent contamination on the surface of the crankcase.
한편, 본 발명은 앞서 설명한 실시예로 한정되는 것이 아니라 본 발명의 요지를 벗어나지 않는 범위 내에서 수정 및 변형하여 실시할 수 있고, 그러한 수정 및 변형이 가해진 것도 본 발명의 기술적 사상에 속하는 것으로 보아야 한다.Meanwhile, the present invention is not limited to the above-described embodiments, but may be modified and modified without departing from the scope of the present invention, and such modifications and variations should be regarded as belonging to the technical spirit of the present invention. .

Claims (9)

  1. 엔진의 하부를 구성하는 로우 크랭크 케이스에 크랭크 축을 지지하는 베어링 인서트를 주조로 인서트하여 일체화시키는 하이브리드 다이캐스팅 방식의 제조방법에 있어서,In the manufacturing method of the hybrid die casting method of inserting and inserting a bearing insert for supporting a crank shaft by casting into a low crank case constituting a lower part of an engine,
    다이캐스팅 금형의 캐비티에 알루미늄 합금재질의 베어링 인서트를 장입하는 인서트 장입단계;An insert charging step of charging a bearing insert made of aluminum alloy into a cavity of a die casting mold;
    상기 인서트 장입단계 후 상기 금형 캐비티에 용융금속을 고속 고압으로 사출하여 로우 크랭크 케이스를 성형하는 다이캐스팅단계;A die casting step of molding a low crank case by injecting molten metal into the mold cavity at a high speed and high pressure after the insert charging step;
    상기 다이캐스팅단계 후 상기 로우 크랭크 케이스를 상기 금형 캐비티에서 취출하는 취출단계; 및Taking out the low crank case from the mold cavity after the die casting step; And
    상기 취출단계 후 로우 크랭크 케이스를 급속 냉각하는 냉각단계;를 포함하고,And a cooling step of rapidly cooling the low crank case after the take-out step.
    상기 냉각단계는,The cooling step,
    상기 취출된 로우 크랭크 케이스를 수조의 냉각수를 통해 수냉식으로 급속 냉각하는 것을 특징으로 하는 엔진용 로우 크랭크 케이스의 제조방법.The method of manufacturing a low crank case for an engine, characterized in that the low crank case is rapidly cooled by water cooling type through the cooling water of the tank.
  2. 청구항 1에 있어서, 상기 냉각단계는,The method of claim 1, wherein the cooling step,
    상기 취출된 로우 크랭크 케이스를 냉각수가 저수된 상기 수조에 장입하는 수조 장입단계;A tank charging step of charging the extracted low crank case into the tank in which cooling water is stored;
    상기 수조에 장입된 상기 로우 크랭크 케이스를 설정된 시간 동안 상기 수조의 냉각수에 침잠시키 침잠단계; 및Immersing the low crank case charged in the tank in the cooling water of the tank for a predetermined time; And
    상기 수조에서 상기 로우 크랭크 케이스를 인출하는 인출단계;를 포함하는 엔진용 로우 크랭크 케이스의 제조방법.And a withdrawal step of withdrawing the low crank case from the water tank.
  3. 청구항 1에 있어서,The method according to claim 1,
    상기 취출된 로우 크랭크 케이스의 온도에 의해 상기 수조에 저수된 냉각수의 수온이 상승하거나 냉각수에서 워터버블이 발생되는 것이 방지되도록, 상기 수조의 냉각수를 순환시키는 냉각수 순환단계;를 더 포함하는 엔진용 로우 크랭크 케이스의 제조방법.And a coolant circulation step of circulating the coolant in the tank so that the temperature of the extracted cool water stored in the tank is prevented from rising or the water bubble is not generated in the coolant by the temperature of the extracted low crankcase. Crankcase manufacturing method.
  4. 청구항 3에 있어서, 상기 냉각수 순환단계는,The method of claim 3, wherein the cooling water circulation step,
    상기 수조에 저수된 냉각수의 일부가 교환되면서 냉각수가 순환되도록, 상기 수조의 냉각수 중 일부의 냉각수를 상기 수조의 외부로 배출하면서 배출된 냉각수의 양에 대응하는 새로운 냉각수를 상기 수조에 보충하는 냉각수 교환단계;로 구성된 엔진용 로우 크랭크 케이스의 제조방법.Cooling water exchange that replenishes the tank with new cooling water corresponding to the amount of cooling water discharged while discharging the cooling water of some of the cooling water of the tank to the outside of the tank so that the cooling water is circulated while a portion of the cooling water stored in the tank is exchanged. Step; Method of manufacturing a low crank case for the engine consisting of.
  5. 청구항 3에 있어서, 상기 냉각수 순환단계는,The method of claim 3, wherein the cooling water circulation step,
    상기 수조의 냉각수를 교반시켜 상기 수조에서 냉각수를 순환시키는 교반단계;로 구성된 엔진용 로우 크랭크 케이스의 제조방법.And stirring the cooling water in the water tank to circulate the cooling water in the water tank.
  6. 청구항 1에 있어서,The method according to claim 1,
    상기 수조에 장입된 상기 로우 크랭크 케이스나 상기 로우 크랭크 케이스를 상기 수조에 장입시키는 엘리베이터 중 적어도 어느 하나를 진동시켜서 냉각수와 상기 로우 크랭크 케이스의 열교환을 증가시키는 바이브레이션단계;를 더 포함하는 엔진용 로우 크랭크 케이스의 제조방법.A vibration step of increasing heat exchange between the coolant and the low crankcase by vibrating at least one of the low crankcase charged in the water tank and an elevator for charging the low crankcase into the water tank; Manufacturing method of the case.
  7. 청구항 1에 있어서,The method according to claim 1,
    상기 수조에서 상기 로우 크랭크 케이스를 인출시켜 압축된 공기를 상기 로우 크랭크 케이스의 표면에 분사하여 상기 로우 크랭크 케이스의 표면에서 물기를 제거하는 에어 블로잉단계;를 포함하는 엔진용 로우 크랭크 케이스의 제조방법.And an air blowing step of extracting the low crank case from the water tank and spraying compressed air to the surface of the low crank case to remove water from the surface of the low crank case.
  8. 청구항 7에 있어서, 상기 에어 블로잉단계 후,The method according to claim 7, After the air blowing step,
    상기 압축된 공기에 의해 물기가 제거된 로우 크랭크 케이스를 자연 건조하는 건조단계;를 더 포함하는 것을 특징으로 하는 엔진용 로우 크랭크 케이스의 제조방법.And a drying step of naturally drying the low crank case from which water is removed by the compressed air.
  9. 청구항 1에 있어서, 상기 냉각단계 후,The method according to claim 1, After the cooling step,
    상기 로우 크랭크 케이스를 열처리하여 내부 응력을 제거하는 어닐링단계;를 더 포함하는 것을 특징으로 하는 엔진용 로우 크랭크 케이스의 제조방법.Annealing step of removing the internal stress by heat treatment of the low crank case; manufacturing method of the low crank case for the engine, characterized in that it further comprises.
PCT/KR2016/013495 2015-12-02 2016-11-22 Production method of low crank case for engine by hybrid die casting WO2017095057A1 (en)

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JP2009243797A (en) * 2008-03-31 2009-10-22 Mitsubishi Electric Corp Water heater
JP2010526670A (en) * 2007-05-16 2010-08-05 ダイムラー・アクチェンゲゼルシャフト Cylinder crankcase manufacturing method
KR20110061380A (en) * 2009-12-01 2011-06-09 현대자동차주식회사 Reinforce low crankcase and method for manufacturing the same, low crankcase
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JP2008248283A (en) * 2007-03-29 2008-10-16 Kobe Steel Ltd Method for quenching forged material of aluminum alloy
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KR20110061380A (en) * 2009-12-01 2011-06-09 현대자동차주식회사 Reinforce low crankcase and method for manufacturing the same, low crankcase

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