WO2022145109A1

WO2022145109A1 - Die-casting manufacturing method and apparatus

Info

Publication number: WO2022145109A1
Application number: PCT/JP2021/038260
Authority: WO
Inventors: 典裕岩本; 理長澤; 圭司谷口
Original assignee: 株式会社ダイレクト２１; リョービ株式会社
Priority date: 2020-12-28
Filing date: 2021-10-15
Publication date: 2022-07-07

Abstract

Provided are a die-casting method and a die-casting apparatus that enable effective prevention of backward flow of molten metal when the pressure in a runner is to be increased after ejection of the molten metal by a plunger and thereby enable effective application of additional pressure to a product having been ejected into a cavity. The die-casting apparatus is provided with an ejection part comprising: a first pressure application means for ejecting molten metal into a die-casting die; a second pressure application means for applying pressure in a runner which is contiguous with a cavity; and an orifice which is formed in the surface of the runner that corresponds to a rising portion of the runner directly connected to the cavity. When a second pressure is to be applied by the second pressure application means through the runner directly connected to the cavity after ejection of the molten metal by the first pressure application means, the pressure application is carried out by the second pressure application means while backward flowing of the molten metal is prevented by the orifice in a pressure application channel of the second pressure application means.

Description

Die casting manufacturing method and equipment

The present invention relates to a die casting manufacturing method and an apparatus, and more particularly to a die casting manufacturing method and an apparatus capable of accurately pressurizing a runner which is a molten metal inlet / outlet of a mold toward a cavity.

The casting method for die-cast products is to push molten metal such as aluminum into the cavity made with a mold with a plunger, cool the product in a shape that follows the cavity, and then take it out for casting. A method of further pressurizing the runner has been proposed in accordance with the pressurizing operation of the plunger so that a nest is not formed when the product is cooled and molded.

The runner consists of a runner part along the extrusion direction of the diversion element connected to the plunger and a rising runner part where the runner orthogonal to this and directly connected to the cavity rises upward, but locally pressurizes the molten metal in the runner. In order to do this, a pressure pin is provided in the rising runner section that is directly connected to the cavity, and after the molten metal filling and pressure increase in the cavity by the plunger is completed, the pressure pin that enters and exits the runner is operated to further pressurize. (Patent Document 1).

In the pressurization from the runner of Patent Document 1, the pressurized portion and the tip surface of the plunger tip are connected, and the pressure that can be pressurized is limited to the pressure pressure that allows the plunger to maintain a stationary state after filling the molten metal. Become. If a pressure exceeding the pressure resistance limit of this plunger is applied to the runner portion, the plunger retracts and the pressure exceeding the pressure resistance limit cannot be applied to the runner portion. In a normal casting machine, this limit pressure is about 70 MPa, and pressurization exceeding this limit is not possible. From this point of view, the technique described in Patent Document 2 has been proposed. A cylinder-shaped portion is processed and installed in a runner portion directly connected to a cavity, and a gap between the inner diameter thereof and the outer diameter of a pressure pin is formed. The diameter is set to 0.5 to 3.0 mm so that the backflow prevention function is exhibited and the pushing effect can be obtained. A cylinder-shaped part is processed and installed in the runner part, and a pressure pin is pushed in to divide the runner into a runner part that is directly connected to the product part and a runner part that is connected to the plunger, thereby realizing a backflow prevention function.

Both Patent Document 1 and Patent Document 2 pay attention to the fact that the pressurization from the runner portion is performed by installing a pressurizing pin in the direction perpendicular to the mold opening direction in the rising runner portion near the shunt. In die casting product casting, especially when the product shape is complicated, it is often the case that multiple branch runners are provided so that the molten metal spreads as evenly as possible throughout the cavity along the product shape. Pressurization from the rising runner part closest to the shunt is premised.

JP 2000-117411 JP 2011-224650

Focusing on the above existing technology, clarify the issues in order to improve the current issues. This technology provides a die-casting method and equipment that can produce die-cast products with high product density by secondarily pressurizing the runner with high pressure after the injection of the molten metal by the plunger and continuously applying high pressure to the molten metal to solidify it. It is what we are trying to provide. In order to avoid the retracting of the plunger due to high pressure applied to the runner part, the rising runner part is processed to provide a cylinder on which the pressure pin slides, and between the inner diameter and the outer diameter of the pressure pin. Although the gap is set to a value that has the effect of preventing backflow, the method focusing only on the existing gap has the following problems and is not realistic. Normally, the product is taken out after casting by grasping the biscuit part, but the product part and biscuit part of the cast product solidified by pushing the pressure pin into the cylinder installed by processing the runner part are the cylinder inner diameter and pressurization. It is in a state of being connected by a thin cylindrical shape formed by a gap with the outer diameter of the pin. Therefore, if the moving length L of the pressure pin of the runner part that moves the rising runner part cylinder becomes long, the strength of the part connecting the biscuit part and the product decreases, and it is damaged at the time of taking out the product and the product taking out fails continuously. Production will be hindered. Generally, the flow rate Q of the annular gap is proportional to the cube of the annular gap Δ and inversely proportional to its length L. Therefore, reducing the gap Δ is effective in preventing backflow, and the limit value at which pressure can be applied to the product portion by the pressure pin from the runner portion is determined by this gap Δ and its length L. On the other hand, the amount of movement of the pressure pin is determined by the predicted amount of cavities generated in the product part. The shrinkage rate of aluminum is 6%, and it is necessary to move the pressure pin to push in the molten metal of about 6% of the product volume in order to prevent the occurrence of shrinkage cavities. In order to enable continuous casting by pressurization from the runner section, the value of the gap Δ between the rising runner section and the pressurizing pin, the movement amount L of the pressurizing pin, and the biscuits and products required for product removal after backflow casting. It is necessary to set the optimum value of the three elements of strength that connect the two, and continuous casting is difficult only with the element that the gap Δ between the inner diameter of the rising runner and the outer diameter of the pressure pin is 0.5 to 3.0 mm. There is a problem that the expected effect cannot be obtained.

In addition, in a mold provided with a branch runner, the flow path of the molten metal becomes complicated, so it is difficult to uniformly fill the entire product with the molten metal and uniformly increase the pressure on the entire product, and imbalance is likely to occur. There was a problem that the density of the product part connected to the runner decreased. It is possible to improve the product density by installing a pressurizing pin near the shunt element of the branch runner mold by the conventional method, but since the pressurization extends to the entire product, pressurization is applied to a specific branch runner with a low product density. There was a problem that it was difficult to obtain the effect. In addition, even in a single runner mold, cavities may occur in a specific part of the product. In this case as well, it is possible to improve the product density by installing a pressure pin near the shunt element of the branch runner mold by the conventional method, but since the pressure is applied to the entire product, the effect of improving the product density of a specific part is obtained. There were limited challenges.

The present invention is configured as follows in order to solve the above problems. That is, in the die casting manufacturing method according to the present invention, after the molten metal is injected into the molded mold by the first pressurizing means, the cylinder-shaped portion is processed and installed in the runner directly connected to the cavity by the second pressurizing means. The second pressurization is performed by the pressurizing pin that moves there, but the second pressurization is performed while preventing the backflow of the molten metal by providing an orifice with a convex groove in the cylinder of the second pressurizing means and using a metal seal at the orifice part. It is characterized in that the cavity is pressurized by a pressurizing means. The convex groove orifice has an effect of preventing backflow, and the length of the thin portion connecting the biscuit portion and the product portion after solidification can be minimized, and the strength can be improved. The required stroke of the pressure pin of the runner part correlates with the expected capacity for shrinkage cavities and is determined by the volume of the product part. I couldn't. By installing the convex groove orifice, it is not affected by the required pressure pin stroke length, and by determining only the gap Δ and the convex groove orifice width, both the backflow prevention effect and the breakage prevention strength at the time of product removal are obtained. be able to. Further, in the prior art, the gap length of the portion where the pressure pin is inserted into the cylinder changes depending on the amount of movement of the pressure pin. Since the flow rate Q of the annular gap is proportional to the cube of the annular gap Δ and inversely proportional to its length L, the backflow prevention effect increases as the pressure pin stroke length increases. On the other hand, when the convex groove orifice is installed, the backflow prevention effect is determined only by the gap Δ and is not affected by the pressure pin stroke length. That is, the backflow effect determining factor changes from the variable value gap length L and the gap Δ that change with the stroke movement amount to the fixed value gap length L and the gap Δ, and is the optimum runner for obtaining a stable backflow prevention effect. Part Pressurization pin Cylinder design is easy.

In addition, as a solution to the problem that the density of the product part connected to the specific branch runner decreases, a pressure pin is installed on the specific branch runner where the density decrease occurs to pressurize the branch runner part. .. The pressurizing pin is characterized in a direction perpendicular to or parallel to the plunger direction. When designing a branch runner, a part that bends in the direction perpendicular to or parallel to the plunger direction is provided in the middle of the molten metal path where the nearest branch runner and the shunt runner are connected to the part where the product density is to be improved. Process and install the cylinder and pressure pin in the same way as the installed cylinder and pressure pin. A convex groove orifice is installed in the cylinder to prevent backflow. This makes it possible to improve the product density of the part connected to the branch runner on which the pressure pin is installed. If you want to improve the density of a specific part of a single runner mold product, you can specify it by newly processing a branch runner connected to that part and installing a cylinder and pressure pin in that part in the same way as above. It is possible to improve the product density of parts.
Further, it is also effective to provide an air-cooled / water-cooled or oil-cooled cooling means in the cylinder convex groove orifice portion to solidify (semi-solidify) the molten metal.

In the existing die casting machine, the molten metal is pushed at low speed through the runner part via the runner part until just before the product part (cavity), then switched to high speed and pushed into the cavity at once, and after filling is completed, the pressure is increased at about 70 MPa by the plunger. And cool. According to the configuration devised this time, secondary pressurization is performed by the pressurizing pin installed in the runner portion before and after the pressurization by the last plunger. The cavity is already filled with molten metal due to filling with a plunger, and stroke movement for filling the molten metal is not required for secondary pressurization with a pressure pin, and the volume of the product part is to suppress the formation of cavities. It suffices if there is a molten metal filling stroke with a shrinkage nest occurrence rate of about 6% or less. Therefore, it is possible to apply a large pressure by a pressure pin having a small diameter that easily applies a high pressure, and it is possible to pressurize about 250 MPa, which is the limit of the strength of the steel material. By the conventional method, the pressure of 70 MPa applied to the product part at the time of cooling becomes 250 MPa, which has the effect of greatly improving the product density. The secondary pressure that can be pressurized by the pressure pin from the runner part is determined by the size of the gap Δ composed of the inner diameter of the cylinder shape and the outer diameter of the pressure pin provided in the runner part and the length of the convex groove orifice part inside the cylinder. However, by providing the convex groove orifice part, it is easy to grasp it as a "combination of the pressurization limit pressure and the gap Δ and the convex groove orifice part length", and it is easy to divert it as an experience value when designing a new mold.

A branch runner is installed in the product mold where a specific part where density reduction is likely to occur depending on the product shape, but in the conventional method, the pressurization is only the plunger, or the secondary pressurization from the runner part immediately after the shunting element. In either case, the pressure is applied to the entire product, so the pressure applied to the target portion is low. The method of installing the pressure pin on the branch runner proposed this time has a great effect of improving the product density of the part because the pressure pin effect is directly connected to the target part. It is possible to set the timing at which the pressure pin is pushed in most effectively according to the characteristics of that part. By providing the convex groove orifice portion in the processing of the cylinder shape portion installed in the branch runner portion, it becomes easy to grasp the relationship between the pressurizing limit pressure and the "combination of the gap Δ and the convex groove orifice portion length".

It is sectional drawing of the main part of the die casting manufacturing apparatus which concerns on Example. It is sectional drawing of the molten metal of the injection part of the die casting manufacturing apparatus of FIG. It is an operation system diagram by the 2nd pressurizing means. It is a schematic front view which included the runner of the die-casting product by the die-casting manufacturing apparatus by the ultra-high pressure which concerns on 2nd Embodiment. It is a schematic side view of FIG. It is sectional drawing of the 2nd pressurizing means attached to the branch runner part. It is a schematic front view which included the runner of the die-casting product by the die-casting manufacturing apparatus by the ultra-high pressure which concerns on another modification. It is a schematic side view of FIG. It is a hydraulic system diagram of a stroke detection device. It is a hydraulic system diagram which concerns on the modification of the stroke detection apparatus.

Hereinafter, the die casting manufacturing method and the manufacturing apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings. It should be noted that the following description is merely an embodiment, and the present invention may include various modifications as long as the gist of the present invention is not changed.

FIG. 1 shows a cross-sectional view of a main part of the die casting manufacturing apparatus according to the first embodiment. The die casting manufacturing apparatus 10 includes a movable mold 14 attached to the moving plate 12 and a fixed mold 18 attached to the fixed plate 16, and is formed in a cavity 20 formed by abutting the

molds

14 and 18. The molten metal is injected to produce a product having a shape that resembles the cavity 20. The product can be taken out from the cavity 20 by separating the

molds

14 and 18 and operating the extrusion pin 22 provided on the back surface of the movable mold 14.

The hot water supply means 24 is arranged below the cavity 20 as an injection unit for supplying the molten metal to the cavity 20 of the die casting manufacturing apparatus 10. This includes an injection sleeve 26 that is mounted horizontally through the fixing plate 16 and reaches the fixed mold 18, a plunger 28 disposed inside the injection sleeve 26, and a plunger 28 behind the plunger 28. It is composed of a first pressurizing means 30 including a pressurizing device (not shown) that can be pushed and pulled.

A runner 32, which is a passage leading to the cavity 20, is formed at the front end of the injection sleeve 26, and the runner 32 is directly connected to the shunter runner portion 34 extending substantially horizontally from the injection sleeve 26 and the lower part of the cavity 20. The molten metal extruded by the plunger 28 of the first pressurizing means 30 passes through the shunter runner section 34 and is upward by the rising runner section 36, which is composed of the rising runner section 36 whose direction is changed upward. It is configured to turn to and inject into the cavity 20.

The rising runner portion 36 in such a runner 32 is provided with a second pressurizing means 38 for secondarily pressurizing the molten metal in the cavity 20. The second pressurizing means 38 includes an actuator (hydraulic cylinder) 40 mounted on the lower portions of the dies 14 and 18, and a pressurizing pin attached so as to move in and out from the lower portion to the upper portion of the rising runner portion 36. It is composed of (actuating piston) 42. The diameter d of the pressure pin 42 is made smaller than the inner diameter D of the rising runner portion 36 so that the pressure pin 42 can slide up and down in the rising runner portion 36. Therefore, the amount of press-fitting of the pressure pin 42 into the rising runner portion 36 improves the density of the product by the cavity 20.

By the way, in this embodiment, the inner diameter thereof is particularly on the rising runner portion 36 side (B portion in FIG. 2) above the intersection (AB section in FIG. 2) between the rising runner portion 36 and the shunt runner portion 34. An orifice 44 is formed to squeeze. This is an annular protrusion 46 having a rectangular cross section formed on the inner diameter portion of the rising runner portion 36, and the height of the protrusion 46 (that is, the inner diameter dimension of the rising runner portion 36) is adjusted to the outer diameter d of the pressure pin 42 as much as possible. It is possible to make a metal seal in the gap. Specifically, although it depends on the size of the cavity 20, half of the difference between the inner diameter D of the rising runner portion 36 and the outer diameter d of the pressure pin 42 is the gap dimension Δ, but the gap dimension Δ is The height of the annular protrusion 46 is determined so as to be 1/2 to 1/3 or less. That is, 1/2 of the difference between the inner diameter of the annular protrusion 46 and the outer diameter d of the pressure pin 42 is the gap dimension δ of the metal seal portion, and δ = Δ × 1/2, preferably δ = Δ × 1/3. The lower limit is the value when the metal seal is damaged. Further, the axial length L of the annular protrusion 46 is set to about 10 mm to ensure that the metal seal is performed.

The second pressurizing means 38 configured in this way starts pressurizing from the position shown in FIG. 3 (1) after the injection by the plunger 28 of the first pressurizing means 30 is completed, and the pressurizing pin 42 (FIG. 3 (2)), the upper molten metal is inserted into the orifice 44 portion to form a metal seal, and a shielding function is exhibited at that portion. Therefore, the metal seal at the orifice 44 portion increases the amount of molten metal filled in the cavity 20, and the pushing operation by the pressure pin 42 increases the stroke to complete the work (FIG. 3 (3)). ).

As a result, the case where the product was made by the normal casting method without pressurizing the runner was regarded as "0", and the increase of + 4 g was observed in the conventional local pressurizing method in which the central portion of the cavity 20 was pressurized (0. 5%), an increase of + 14 g was observed according to the runner pressurization method of this example (1.7%), and the effect of this example was remarkable.

The annular projection 46 forming the orifice 44 may have a square cross section as in the embodiment, but may have a V-shaped or arc-shaped cross section. In this case, if the V-shaped or arc-shaped cutting edge is sharp, the metal seal cannot be removed, so it is desirable to have a shape with the tip cut off.

Further, a cooling means can be arranged on the annular projection 46 forming the orifice 44. This can be done by the horizontal method, the water cooling method, or the oil cooling method, and when the injection by the first pressurizing means 30 is completed and the pressurization by the second pressurizing means 38 is applied to the annular projection 46 (FIG. 3 (FIG. 3). 2)) Cool it. This makes it easier to form a metal seal.

In the above embodiment, the annular projection 46 forming the orifice 44 may be formed as a separate component, and may be attached by an inset structure when forming the runner 32. This is because the runner 32 is split by the dividing line of the mold, so that it can be easily attached to the rising runner portion 36 having a semicircular structure.
Further, the above embodiment can be applied to push the runner of the hot chamber and also to mold plastic.

As described above, according to the present embodiment, the injection into the cavity 20 is performed by the first pressurizing means 30, and the second pressurizing means 38 is operated from the state where the runner 32 is filled with the molten metal. Then, while the pressurizing pin 42 reaches the intersection (FIG. 2A → B) between the shunt runner portion 34 and the rising runner portion 36, a normal pushing action is performed, but the shunting element runner portion 34 is cut off and the rising runner portion is cut. As soon as it reaches 36, it reaches the annular projection 46 portion, and the molten metal is solidified by the metal seal in the gap δ, where the pressure is cut off (FIG. 3 (2)). Therefore, the runner molten metal on the cavity 20 side, which is located above the pressure pin 42 and has not yet solidified, is pushed toward the cavity 20 side against the background of the cutoff pressure.

Thereby, the pressurizing pin 42 can be advanced more than the conventional stroke, and the second pressurizing means 38 can manufacture a more precise product. The effect at this time is a weight increase of 1.7% when the molten metal is filled in the cavity 20 having the same volume, which is an amazing value in this industry.

Next, a second embodiment of the present invention will be described.
Figures 4 to 5 show AsCast (die-cast products manufactured by die-casting equipment, branch runners to products) by partial ultra-high pressure according to this embodiment, and installation of ultra-high pressure pressure cylinders mounted on the specific branch runners. A schematic front view and a schematic side view showing the position are shown. As shown in these figures, the die-cast product 110 has the biscuit 112 extruded from the plunger side as the front end, and the runner, which is the passage from the biscuit 112 to the cavity, bends and rises upward (shunter base runner 114). A plurality of runners (branched into four in the illustrated example) are further branched (branched

runners

116a, 116b, 116c, 116d), and

gates

118a, 118b, 118c, 118d are formed at four locations of the die casting product 110. It is open through.

Since there was a problem that nests were likely to occur when the molten metal ejected from the left branch runner 116a shown in FIG. 4 solidified in the product, this branch runner 116a was selected as the runner connected to the intended product part. After injecting the required amount of molten metal into the die casting product 110 by the first pressurizing means 120 (see FIG. 5), the second pressurizing means 122 (see FIG. 6) provided in the selected branch runner 116a is used. The secondary pressurization is performed at an ultra-high pressure that is about four times the primary pressurization.

Above the front end of the injection sleeve 130, a runner is formed to serve as a passage leading to the cavity 128, which is composed of a shunt base runner 114 before branching and four

branch runners

116a, 116b, 116c, 116d, followed by the

branch runners

116a, 116b, 116c, 116d. The

gates

118a, 118b, 118c, and 118d inject molten metal into the cavity 128 to form the die-cast product 110. Now, it is assumed that the die-cast product 110 has a problem that many nests are generated in the product portion ejected from the branch runner 116a at the left end of FIG.

Therefore, the branch runner 116a is selected, and the secondary pressurization is performed by the selected branch runner 116a portion. In this embodiment, the second pressurizing means 122 is arranged on the mold clamping surface of the mold, and the operating direction of the pressurizing pin 134 constituting the second pressurizing means 122 is defined as the pushing direction of the plunger 132. It is set to be orthogonal to the upward direction (see FIG. 5).

In FIGS. 4-6, the selective branch runner 116a is a first shunt runner 136 that is branched from a shunt base runner 114 that is substantially extended from the injection sleeve 130 and extends diagonally upward, followed by a vertical. It has a bent shape consisting of a rising runner 138 following. The rising runner 138 is connected by turning upward so as to be finally directly connected to the lower part of the cavity 128, and the molten metal extruded by the plunger 132 passes through the shunter base runner 114 and is connected by the rising runner 138. It is configured to turn upward and inject from the gate 118a into the cavity 128.

The first shunting runner 136 in such a branch runner 116a is provided with a second pressurizing means 122 for secondarily pressurizing the molten metal in the cavity 128. The second pressurizing means 122 is provided along the mold clamping surface, and is provided from the lower actuator 140 and the pressurizing pin 134 attached so as to move in and out along the rising runner 138 (pressurizing path). It is configured. The stroke amount of the pressurizing pin 134 in the rising runner 138 of the selective branch runner 116a becomes a hot water pool required for secondary pressurization. The diameter d of the pressure pin 134 is made smaller than the inner diameter D of the rising runner 138 so that the pressure pin 134 can slide up and down in the rising runner 138. Therefore, the amount of press-fitting of the pressure pin 134 into the rising runner 138 (the amount of hot water that is pushed away) improves the density of the product due to the cavity 128.

By the way, in this embodiment, in particular, the first shunting runner 136 side (FIG. 6) from the intersection of the first shunting runner 136 and the rising runner 138 (AB section in FIG. 6) in the selected branch runner 116a. An orifice 144 is formed in the B portion) to narrow the inner diameter thereof. In this case, an annular protrusion 146 having a rectangular cross section is formed on the inner diameter portion of the rising runner 138, and the height of the annular protrusion 146 is adjusted to the outer diameter d of the pressure pin 134 as much as possible so that a metal seal can be formed here. ing. Specifically, although it depends on the size of the cavity 128, it is desirable that the gap between the pressure pin 134 and the annular protrusion 146 in the rising runner 138 is empirically about 1 mm from which the metal sealing effect by solidification of the molten metal can be obtained. This optimum value varies depending on the axial length of the annular protrusion 146, the mold shape, the injection pressure, and the speed, but is often about 0.5 mm to 1.0 mm on average. Further, the axial length L of the annular protrusion 146 is often about 10 mm on average in order to obtain a high metal sealing effect, but it varies depending on the mold shape, injection pressure, speed, and the like. These ensure that the metal seal is performed.

When the pressurizing pin 134 approaches the annular projection 146 after the injection by the plunger 132 of the first pressurizing means 120 is completed, the second pressurizing means 122 configured in this way is higher than the orifice 144 portion. The molten metal is inserted to form a metal seal, which exerts a shielding function. Therefore, the metal seal at the orifice 144 portion increases the amount of molten metal filled in the cavity 128, and the pushing operation by the pressure pin 134 lengthens the stroke to complete the work.

At this time, the start time of the second pressurizing means 122 after the injection by the first pressurizing means 120 is completed (about 70 MPa) can be set by providing the control unit 148 (see FIG. 5). In this case, in the embodiment, the second pressurizing means 122 is started with a delay of about 0.1 seconds after the injection by the first pressurizing means is completed. In the example, it is about 0.1 second, but the optimum value of this delay time differs depending on various conditions such as the mold shape, the first pressurizing pressure, and the pressurizing speed, so it is determined by some trial. Although necessary, the time of this device can be set by mSec order. This time setting may be the time during which the metal seal at the injection port of the

non-selective branch runners

116b, 116c, 116d not provided with the second pressurizing means 122 is exhibited. The molten metal comes into contact with the mold and solidifies, and the part that does not come into contact is in a state of semi-solidification. Therefore, the partial pressurization by the second pressurizing means 122 is performed at an ultrahigh pressure (about 250 MPa) by performing the metal seal at the orifice 144 while aiming at the metal seal at the

non-selective branch runners

116b, 116c, 116d. Can be done. That is, it is possible to partially pressurize about four times as much as the first pressurizing means 120.

As described above, according to the present embodiment, the injection into the cavity 128 is performed by the first pressurizing means 120, and the second pressurizing means 122 is operated with a slight delay from the state where the runner 116a is filled with the molten metal. Then, while the pressurizing pin 134 reaches the intersection of the first shunt runner 136 and the rising runner 138 (FIG. 6A → B), the normal pushing action is performed, but the first shunt runner 136 is cut and the orifice 144 is cut. As soon as it reaches, the annular projection 146 reaches the portion, and the molten metal is solidified by the metal seal in the gap δ, where the pressure is cut off. At this time, the injection ports of the non-selective branch runners 116b to 116d are in a solidified state, and the mouth is closed. Therefore, the runner molten metal on the cavity 128 side, which is located above the pressure pin 134 and has not yet solidified, is pushed toward the cavity 128 side against the background of the cutoff pressure.

As a result, the pressurizing pin 134 can be advanced more than the conventional stroke, and the second pressurizing means 122 can produce a partially high-strength and more precise product. The effect at this time is that when the cavity 128 of the same volume is filled with the molten metal, the weight increases by 1.7%, which is an amazing value in this industry.
In the above embodiment, the second pressurizing means 122 is arranged along the direction perpendicular to the plunger stroke (mold tightening surface), but the second pressurizing means 122 can be pressurized along the fixed mold 126 side. It may be provided.

Figures 7 to 8 show modified examples of this second embodiment. In this example, since the product portion 133 has a flat plate shape, the mold clamping line is perpendicular to the plate surface. The plunger 132, which is the first pressurizing means 120, is configured to move from the front side to the back side in FIG. 7, and passes through the routes from the four

branch runners

116a, 116b, 116c, 116d, and the die casting product 110. It will be extruded to. The second pressurizing means 122, which is performed after the extrusion by the first pressurizing means 120 is completed, forms a runner formed in the selected branch runner 116a in parallel with the operating direction of the plunger 132, and is attached to the parallel runner 150. The pressure is increased in parallel with the plunger 132. In this case, the parallel runner 150 is provided with an orifice 144, on which the pressurizing pin 134 slides. The pressurization start time by the second pressurizing means 122 is also slightly delayed after the completion of the injection by the first pressurizing means 120, and is configured to operate after the delay time set in the control unit 148 (see FIG. 5). This enables partial ultrahigh pressure (250 MPa) by the second pressurizing means 122.

In the examples shown in FIGS. 7 to 8, the second pressurizing means 122 has the pressurizing pin 134 attached together with the actuator 140 in the fixed mold, but if this does not fit, the actuator 140 is located on the fixed plate side. May be extended and arranged.

Further, in the above embodiment, it is assumed that the product has branch runners 116a to 116d from the beginning, but if a relatively large number of new nests are found in the product apart from the branch runner portion, the location is assumed. A new branch runner may be provided, and the new runner portion may be subjected to partial pressurization (about 250 MPa) higher than the plunger pressure (about 70 MPa) by the second pressurizing means 122. Further, in the case of a mold for forming a product with a single runner, the formation of a nest can be partially prevented by forming a new runner portion and forming the second pressurizing means 122 here. It is possible to respond in detail to each product.

Further, when there are a plurality of branch runners leading to the portion where the density is desired to be increased, a shunter base runner is used to combine these, and a second pressurizing means is provided on the shunter base runner, whereby the plurality of branch runners are formed. Secondary pressurization is also possible.

By the way, in the die casting manufacturing method and the apparatus in any of the above embodiments, the second pressurizing means is operated after the first pressurizing means for injecting the molten metal into the die casting die completes the injection. In this case, the time when the casting by the first pressurizing means for injecting the molten metal into the die-casting die is completed is grasped from the injection speed or the injection pressure of the first pressurizing means, and when the injection speed decreases or the injection pressure increases, the casting is performed. As a starting point, a second pressurizing means for pressurizing the runner communicating with the cavity is operated. From this casting point to the operation of the second pressurizing means, the runner may be pressurized after the set time has elapsed. For example, the injection speed of the plunger rises to a certain speed as it approaches the completion of casting, and then a point that can be confirmed by the sudden start of descent, or a point that can confirm a sudden rise in the die casting machine chip pressure is sought, and a certain period of time is obtained from that point. This can be achieved by activating the second pressurizing means after the lapse of time (about 0.1 seconds).

Here, in any of the above-described embodiments, the stroke amount of the pressurizing pin of the secondary pressurizing means is measured. A pressure cylinder that operates this pressure pin is built in, and here a cylinder body that measures the amount of discharged oil is provided in the hydraulic oil discharge path of the pressure cylinder, and a check valve is attached to the piston of this measurement cylinder body. An orifice (throttle valve) is integrally provided, and drainage is provided via a solenoid valve in a path branching from the discharge path side of the pressure cylinder. Further, a cylinder body for measuring the amount of discharged oil is provided in the hydraulic oil discharge path of the pressure cylinder, and a check valve and an orifice (throttle valve) are provided in the path bypassing the measurement cylinder body to provide the local pressure cylinder. A drain drain may be provided via a solenoid valve in the path branching from the discharge path side. Alternatively, a cylinder body for measuring the amount of discharged oil is provided in the hydraulic oil discharge path of the pressure cylinder, and an orifice (throttle valve) is integrally provided with the piston of the measurement cylinder body from the discharge path side of the local pressure cylinder. A drain drain may be provided in the branching path via a solenoid valve.

FIG. 9 shows an example of a stroke detection device provided in the discharge oil system of the pressure cylinder 410 having a built-in pressure pin 416. First, the pressurizing cylinder 410 has a cylinder body 412 and a built-in piston 414, and a pressurizing pin 416 integrated with the piston 414 is projected from the cylinder body 412 to pressurize the cavity of a casting device (not shown). It is attached so that the pin 416 can be moved in and out. The pressure pin 416 of the pressure cylinder 410 is inserted into the cavity just before the molten metal cast in the cavity solidifies, and the pressure pin 416 pressurizes the cavity by the volume pushed away. Therefore, hydraulic oil is supplied to the oil supply passage on the cylinder head side via the pump 418, the direction switching valve 420, and the throttle valve 422, and the hydraulic oil on the cylinder rod side passes through the direction switching valve 420. Then, it returns to the tank 424.

In the oil drainage system of the local pressure cylinder 410, a stroke detection device 426 is provided between the hydraulic oil outlet of the pressure cylinder 410 and the direction switching valve 420 in order to measure the push stroke of the pressure cylinder 410. It is arranged and is designed to measure the amount of hydraulic oil discharged from the room on the cylinder rod side of the pressure cylinder 410.

The stroke detection device 426 is composed of a cylinder piston structure, which is composed of a cylinder body 428 and a piston 430 that can slide inside the cylinder body 428. One chamber partitioned by the piston 430 of the cylinder body 428 is connected to the hydraulic oil outlet of the pressure cylinder 410, and the other chamber is connected to the direction switching valve 420. As a result, the hydraulic oil discharged from the local pressure cylinder 410 enters the stroke detection device 426 by the amount discharged, and the piston 430 is moved. The piston 430 is integrally provided with a pressure pin 432, which projects from one end of the cylinder body 428 and is connected to a linear potentiometer 434. The operation start point of the pressurizing pin 432 is set to one end side (left end in FIG. 9) of the cylinder body 428, and at this time, coincides with the pressurizing start point (upper end in FIG. 9) of the piston 414 of the local pressurizing cylinder 410. There is. Therefore, when the pressure operation of the local pressure cylinder 410 is in the start position, the piston 430 of the stroke detection device 426 is located at the operation start point, and the piston of the stroke detection device 426 is located together with the pressure operation by the pressure cylinder 410. In 430, the hydraulic oil moves by injection and moves proportionally.

The linear potentiometer 434 is arranged in parallel with the pressurizing pin 432 and moves together with the pressurizing pin 432 to obtain the moving distance. Therefore, the movement of the pressure pin 432 appears as the output of the linear potentiometer 434. Further, a limit switch 436 is arranged at the operation start point of the pressure pin 432. The limit switch 436 is turned on when the pressurizing pin 32 is located at the operation start point, that is, the piston 430 is located at the left end of the cylinder body 428, whereby the stroke detection start position is detected.

In such a stroke detection device 426, the piston 430 is provided with a through hole that communicates the rooms partitioned by the piston 430, and a check valve 438 and an orifice (throttle valve) 439 are attached to the through hole. ing. This check valve 438 is a one-way valve that blocks the flow of hydraulic oil pushed out from the room where the hydraulic oil of the local pressure cylinder 410 enters to the room on the direction switching valve 420 side, and allows the flow in the opposite direction. Will be done. As a result, the total amount of hydraulic oil when the local pressure cylinder 410 performs the pressurization operation is detected by the stroke detection device 426, and when the stroke detection device 426 returns to the origin position, that is, the operation start point, or the local pressure cylinder 410 When returning to the operation start point, when the amount of oil from the local pressure cylinder 410 to the stroke detection device 426 is insufficient for some reason such as hydraulic oil leakage, the oil is replenished through the pump 418. The orifice (throttle valve) 439 regulates the flow rate of the check valve 438. Further, if the cracking pressure (spring force) of the check valve 438 is weak, the check valve flows in a state where the piston is stopped, so that the problem can be solved by reducing the flow rate. The orifice (throttle valve) 439 may be a variable throttle, or may be a fixed throttle if necessary.

Further, a branch path 440 leading to the tank 424 is provided in the path leading to the discharge oil outlet of the local pressure cylinder 410 and the stroke detection device 426, and the check valve 442 and the solenoid valve 444 are interposed in the branch path 440. This branch path 440 acts as a drain drain, and when the pressurizing pin 432 of the stroke detection device 426 does not press the limit switch 436, it is considered that gas in the hydraulic oil in the path is mixed, and the limit switch 436 is set. The solenoid valve 444 is operated every shot or periodically until it enters to vent the gas.

In such a stroke detection device 426, when the pressurization work by the local pressurizing cylinder 410 is started, the piston 414 is pushed down in FIG. 9, and the total amount of the hydraulic oil used for the pressurization is one of the stroke detection devices 426. Enter the room and press the piston 430 toward the direction switching valve 420. At this time, the check valve 438 provided on the piston 430 is in a shielded state, so that the amount of movement of the piston 30 is proportional to the amount of movement of the local pressure cylinder 410. Since the potentiometer 434 is connected to the piston 430, the movement amount of the operating piston 414 of the local pressure cylinder 410 can be accurately read by reading the potentiometer 434.

Then, when the direction switching valve 420 is switched, the return operation of the local pressurizing cylinder 410 is started, the pressure of the pump 418 is applied to the piston 430 of the stroke detection device 426, and the operation used for pressurization by the local pressurizing cylinder 410. The entire amount of oil is pushed back. The amount of push-back oil moves the piston 430 of the stroke detection device 426 to the origin position, and pushes the piston 414 of the local pressure cylinder 410 back to the origin position. The stop position is detected by the limit switch 436, and the pump 418 stops and ends.

Here, since the check valve 438 is provided on the piston 430 of the stroke detection device 426, the amount of oil from the piston discharge path of the local pressure cylinder 410 to the stroke detection device 426 is reduced due to oil leakage or the like. If so, it is replenished through the check valve 438, and the piston 430 of the stroke detection device 426 and the piston 414 of the local pressure cylinder 410 are returned to the origin position.

On the contrary, when the amount of oil from the piston discharge path of the local pressurizing cylinder 410 to the stroke detection device 426 increases due to the expansion of the internal gas or the like, the solenoid valve 444 provided in the branch path 440 is used for each shot or periodically. It is opened and the origin position of the piston 430 of the stroke detection device 426 and the piston 414 of the local pressurizing cylinder 410 are returned.
In the above example, the check valve 438 and the orifice (throttle valve) 439 are provided on the piston 430, but this can be realized by the orifice (throttle valve) 439 alone.

Next, FIG. 10 shows another example. This modification is different in that a bypass path 446 is provided in the cylinder body 428, and a check valve 438A and an orifice (throttle valve) 439A are provided in the bypass path 446. Even in this way, the same effect as in the previous example can be obtained. That is, when the amount of oil from the piston discharge path of the local pressure cylinder 410 to the stroke detection device 426 is low due to oil leakage or the like, it is replenished through this check valve 438A, and the piston 430 of the stroke detection device 426 or The origin position of the piston 414 of the local pressure cylinder 410 is returned to the original position.

The present invention is a method and device capable of pressurizing a runner by a second pressurizing means following the plunger pressurization of the first pressurizing means for die casting production, and can improve the product density.

10 ... Die cast manufacturing equipment, 12 ... Moving plate, 14 ... Movable mold, 16 ... Fixed plate, 18 ... Fixed mold, 20 ... Cavity, 22 ... Extruded pin, 24 ... Hot water supply means, 26 ... Injection sleeve, 28 ... Plunger, 30 ... First pressurizing means, 32 ... Runner, 34 ... Divider runner section, 36 ... Rising runner section, 38 ... Second pressurizing means, 40 ... actuator, 42 ... pressure pin, 44 ... orifice, 46 ... annular protrusion, 110 ... die cast product, 112 ... biscuits, 114 ... branch base runner, 116a, 116b, 116c, 116d ... ... Branch runner, 118a, 118b, 118c, 118d ... Gate, 120 ... First pressurizing means, 122 ... Second pressurizing means, 124 ... Movable mold, 126 ... Fixed mold, 128 ... Cavity, 130 ... Injection sleeve, 132 ... Plunger, 134 ... Pressurized pin, 136 ... 1st branch runner runner, 138 ... Rising runner, 140 ... Actuator, 144 ... orifice, 146 ... Circular Projection 148 ... Control unit, 150 ... Parallel runner, 410 ... Pressurized cylinder, 412 ... Cylinder body, 414 ... Piston, 416 ... Pressurized pin, 418 ... Pump, 420 ... Direction switching valve 422 ... Squeeze valve, 424 ... Tank, 426 ... Stroke detector, 428 ... Cylinder body, 430 ... Piston, 432 ... Pressure pin, 434 ... Potential meter, 436 ... Limit switch, 438 ... ... check valve, 439 ... orifice (throttle valve), 440 ... branch path, 442 ... check valve, 444 ... solenoid valve, 446 ... bypass path.

Claims

After injecting the molten metal into the molded mold by the first pressurizing means, when performing the second pressurization through the runner directly connected to the cavity by the second pressurizing means, an orifice is applied to the pressurizing path of the second pressurizing means. A die casting manufacturing method, characterized in that a cavity is pressurized by a second pressurizing means while preventing backflow of molten metal by a metal seal at the orifice portion.
The die casting manufacturing method according to claim 1, wherein the orifice is formed on a surface corresponding to a rising runner portion directly connected to a cavity in the runner, and a metal seal is used to prevent backflow of molten metal.
The orifice is injected into the cavity via a plurality of branch runners, and the orifice is formed on the surface corresponding to the rising runner portion or the vicinity portion of the selected branch runner, and the backflow of the molten metal is performed by the metal seal. The die casting manufacturing method according to claim 1, wherein the die casting method is characterized in that.
The die casting manufacturing method according to claim 1, wherein the moving direction of the pressurizing pin of the second pressurizing means is a direction intersecting the plunger direction of the first pressurizing means.
The die casting manufacturing method according to claim 1, wherein the moving direction of the pressurizing pin of the second pressurizing means is a direction parallel to the plunger direction of the first pressurizing means.
The die casting manufacturing method according to claim 1 or 3, wherein a second pressurization is performed on the cavity by a new branch runner connected to a portion where the density is desired to be improved.
After injecting the molten metal into the molded mold by the first pressurizing means, the second pressurizing is performed through the runner directly connected to the cavity by the second pressurizing means.
The runner is an auxiliary runner provided at a position where the molten metal filled in the cavity overflows by the first pressurizing means.
A die casting manufacturing method, characterized in that a second pressurizing means is operated to pressurize the cavity from an auxiliary runner after the pressurization of the first pressurizing means is completed.
The first pressurizing means for injecting molten metal into the die casting mold,
A second pressurizing means that pressurizes the runner that communicates with the cavity,
An orifice formed on the surface corresponding to the runner directly connected to the cavity and through which the pressurizing pin of the second pressurizing means is inserted.
A die casting manufacturing device characterized by having an injection section made of.
The die casting manufacturing apparatus according to claim 8, wherein the orifice is formed in the vicinity of a boundary portion between the shunt runner portion and the rising runner portion that guide the molten metal injection from the second pressurizing means to the cavity.
8. The runner is composed of a plurality of branch runners, an orifice is formed on a surface corresponding to the selected branch runner, and a pressurizing pin of a second pressurizing means can be inserted into the orifice. The die casting manufacturing apparatus described in.
The die casting manufacturing apparatus according to claim 8 or 10, wherein the moving direction of the pressurizing pin of the second pressurizing means intersects with the plunger direction of the first pressurizing means.
The die casting manufacturing apparatus according to claim 8 or 10, wherein the moving direction of the pressurizing pin of the second pressurizing means is a direction parallel to the plunger direction of the first pressurizing means.
The first pressurizing means is provided with a new branch runner connected to a portion where the density is to be improved, and a second pressurizing means having a pressurizing pin that moves in the new branch runner in the same direction as the flow of the molten metal is provided. The die casting manufacturing apparatus according to claim 8 or 10.
The first pressurizing means for injecting molten metal into the die casting mold,
A second pressurizing means that pressurizes the runner that communicates with the cavity,
The runner is an auxiliary runner provided at a place where the molten metal filled in the cavity overflows by the first pressurizing means.
A control unit that activates the second pressurizing means to pressurize the cavity from the auxiliary runner after the pressurization of the first pressurizing means is completed.
The die casting apparatus according to claim 8, wherein the die casting apparatus is provided.