WO1980001656A1

WO1980001656A1 - Die-casting method and apparatus

Info

Publication number: WO1980001656A1
Application number: PCT/JP1979/000033
Authority: WO
Inventors: H Suzuki; S Hashimoto
Original assignee: Nippon Denso Co; H Suzuki; S Hashimoto
Priority date: 1979-02-14
Filing date: 1979-02-14
Publication date: 1980-08-21
Also published as: GB2056338A; JPS602947B1; GB2056338B; DE2953435T1; DE2953435C2

Abstract

A die-casting method and apparatus adapted to be used for production of, for example, housing members of compressors, pumps or the like, wherein a molten metal injected into a forging die cavity (30) may be applied with pressure through a location other than an injection port. This invention has for its object to improve the sliding property of a plunger (36) for applying the forging pressure. The pressure plunger (36) is slidably fitted in a pressure sleeve (35) which has an enlarged portion (35a), said pressure plunger (36) being also provided with a reduced portion (36d), so that the pressure plunger (36) may be smoothly moved with the solidified metal layer being kept in the minute gap formed between the pressure sleeve (35) and the pressure plunger (36). Thus, the flash of the solidified metal layer is prevented from clogging in a portion between the pressure sleeve (35) and the pressure plunger (36), so that the sliding movement of the pressure plunger (36) is kept normal.

Description

Description Title of invention Die casting method and apparatus

2 TECHNICAL FIELD The present invention relates to a die casting method and an apparatus. More specifically, the present invention relates to a method of injecting molten metal into a mold and pressurizing the molten metal from a point outside the injection point. The present invention relates to such a die force method and apparatus. ·

3 Background Art Conventionally, a die casting method in which a molten metal filled in a mold is pressed from a place other than a place where the molten metal is injected is disclosed in, for example, — What was disclosed in Japanese Patent Publication No. 1 298 7 17] ?, but in the case of this publication, the pressurization for pressurizing the molten metal filled in the mold space for product production was carried out. The fitting structure between the plunger and the pressurizing passage into which the pressure plunger is tightly and slidably fitted is specially formed only by being formed in a cylindrical shape. Not considered. ·

However, according to the experimental study of the present inventor, even if the pressure plunger and the pressure passage are tightly fitted, the pressure Since the pressurizing pressure of the jerk is as high as 100 atm or more, the inner diameter of the pressurizing passage is slightly elastically deformed and expanded, thereby increasing the pressure inside the pressurizing passage. A slight gap is formed between the wall surface and the outer periphery of the tip of the pressurized bridge, and the molten metal enters into this slight gap. This causes a problem that the pressurized plunger cannot be smoothly slid because of this. If the sliding of the pressurized plunger occurs, the frictional resistance during the sliding of the pressurized plunger sharply increases, and is added to the unsolidified molten metal in the mold space. Pressure is substantially reduced, so that the hot water effect cannot be obtained satisfactorily, and as a result, the hot water is supplied by the pressurized plunger. It has been shown that it is not possible to suppress the occurrence of foci of die-cast products. In addition, when the galling of the barrel proceeds as described above, a serious failure such as inability of the pressurized plunger to slide may occur.

4 Disclosure of Invention ''

According to the present invention, as described above, poor sliding of the pressurizing plunger occurs, and the pressure of the hot water against the unsolidified molten metal is insufficient, thereby causing porosity. In consideration of the experimental research facts, it was considered that the pressure was increased while holding the solidified layer of the molten metal in the minute gap between the tip of the pressure plunger and the pressure passage. To move the runner forward to make hot water

The friction of the molten metal against the outer peripheral surface of the pressure plunger] is reliably prevented, and poor sliding of the pressure plunger is prevented. An object of the present invention is to provide a die casting method and apparatus capable of reliably maintaining the effect of a hot water on a solidified molten metal for a long time even in mass production and reliably preventing the occurrence of nests. It is a thing.

In order to achieve the above object, the present invention provides "a plurality of molds are brought into close contact with each other]), a mold space for manufacturing a product, and a molten metal introduced into the mold space with one end opened in the mold space. Forming an injection passage and a pressurizing passage communicating with the mold space at a position different from the injection passage. The injection passage is formed into the mold space and the pressurized passage at a predetermined pressure. The molten metal is filled in the mold space and the pressurized passage, and then the pressurized plunger in the pressurized passage is advanced. In the die casting method for extruding the molten metal in the pressurizing passage to pressurize the molten metal in the mold space, when the molten metal is pressurized by advancing the pressure plunger, A solidified layer of molten metal is sandwiched in a minute gap between the outer peripheral surface on the tip end side of the pressurizing plunger and the inner peripheral surface of the pressurizing passage. Ka圧Pu run-di catcher die mosquito be sampled wherein that you advancing and die mosquito be sampled apparatus order to implement the method. It's also summarized as j.

According to the present invention, in the minute gap between the outer peripheral surface of the pressurizing plunger and the inner peripheral surface of the pressurizing passage, the pressurized flanger is sandwiched between the molten metal and the solidified layer of the molten metal. To prevent the molten metal from sticking to the outer peripheral surface of the pressure plunger.

ΟΜΡΙ

';-, ⁰ The smooth sliding action of the pressure plunger can be maintained well over a long period of time, so that the unsolidified molten metal in the mold space can always be pressurized with sufficient pressure to generate porosity. This can be prevented reliably. 5 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of an apparatus used to carry out the method of the present invention, and FIGS. 2 and 3 are pressurized plungers 3 shown in FIG. 6, a cross-sectional view showing the basin section 32, FIG. 2 shows a state in which the pressurized blower 36 is retracted most, and FIG. 3 shows a depressurized pressurized blower. 36 shows the most advanced state. O Fig. 4 is an explanatory diagram for explaining the relationship between the time lag and the amount of hot water, and Figs. 5 (a) and 5 (b) are Reference photos showing the structure of the die cast product where defects and segregation have occurred. Fig. 6 is an explanatory diagram for explaining the relationship between the amount of hot water and product density. Fig. 8 is a partial cross-sectional view used to explain the generated solidified layer, Fig. 8 is an explanatory diagram used to explain the relationship between the elapsed time after filling and the thickness of the solidified layer, and Figs. 9 (a) and 9) are Fig. 1 Sectional and plan views showing the shape of the die-cast product to be manufactured. Fig. 10 shows the structure of the manufactured product part. Fig. 11 shows the present invention. FIG. 9 is an explanatory diagram showing the difference in product density between the product obtained by the method and the die casting method using a high pressure. Figs. 12 and 13 show another embodiment of the present invention.

OMPL- Fig. 12 is a cross-sectional view of the tip of the plunger. Fig. 12 shows the retraction state of the pressure plunger 36, and Fig. 13 shows the retraction state of the pressure plunger 36. Shows the most forward state.

6 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on an embodiment shown in the drawings. In FIG. 1, reference numeral 1 denotes a fixing stand of the apparatus, which is fixed to a floor of a factory or the like via an embedded bolt (not shown). Reference numerals 2 and 3 denote injection cylinder holders fixed to the fixed base 1, which hold the injection cylinder 4 fixedly. An injection piston 5 is slidably held on the cylindrical inner surface 4'a of the injection cylinder 4], and the first and second openings at both ends of the injection cylinder 4 In response to the hydraulic pressure of signal hydraulic pipes 6, 7-] ?, injection piston 5 can be displaced in injection cylinder 4 in the horizontal direction in the figure.

The signal pressure is a hydraulic pump shown in the figure. Introduced via the input pipe 8 and sent to one of the first and second signal hydraulic pipes 6 and 7 by the hydraulic switching lever 7 made of a solenoid valve. ), The oil in the injection cylinder 4 pushed out by the injection piston 5 is removed from the signal hydraulic pipe on the side to which the signal pressure is not supplied. 6 or 7 'and via oil / pressure switching valve 9: output. Type 10)]) It is sent to the hydraulic pump side shown)). Also, 11 is the pressure signal installed in the middle of the first signal hydraulic pipe 6.

li When the hydraulic pressure in the first fi-pipe 6 is higher than a predetermined pressure (for example, a pressure that is about 50 to 80% larger than the maximum value of the injection pressure described later) at the casting. At that time, an electric signal is applied to a hydraulic switching bubble 42 described later.

Then, the displacement of the injection piston 5 is transmitted to the injection projector 13 through the injection rod 12, and the injection projector 13 is moved to the injection sleeve 14. It slides in the horizontal direction in the figure. Reference numeral 15 denotes a hot water supply port for the molten metal, which is located on the upper side of the injection sleeve 14 when the injection plunger 13 is retracted most (the state shown in FIG. 1). Provided in i? A molten metal such as an aluminum alloy, a magnesium alloy, or a zinc alloy is supplied from a molten metal injector (not shown) into the emission sleeve 14 from the hot water supply port 15. It is rising. Therefore, the injection sleeve 14 forms a part of the injection path of the molten metal. Reference numeral 16 denotes a fixed support fixed to the fixed member 1 and fixedly holds the fixed fixed member 18.], FIG. 1 shows only the left end of the clamping rod 22. However, actually, it is also provided at the right end of the tightening rods 22, 22. The fixed mold 18 obtains a precise mold shape for reasons such as enhancing the maintainability, etc.)), and a fixed block 19 made of die-titanium (FCD55) It is divided into a fixed core 20 made of an intermediate tool steel (SKD61) and is fixed to the fixed block 19 and the fixed core 2 by a hexagon socket head bolt 21. Are connected. The injection sleeve 14 described above penetrates through the fixed support 16 and the fixed block 19, and is fixed to the fixed block 1'9.

OJV.PI

W1PO It is open to the end face.

Further, on both upper and lower sides of the fixed support 16, two fastening rods 22, 22 are fixed one by one.], And the fastening rod 22 penetrates the movable support 23. The movable support 23 is supported by the tightening rod 22 in a tight state so that it can slide on the fixed joint 1 in the left and right direction in the figure.] 9, not shown. It can be displaced by the driving force of the stone.

A movable mold 26 is fixed to the movable mold support 23 through a side clamp plate 24 and upper and lower clamp plates 25, 25. The movable mold 26 is also fixed as described above. As with the fixed type 18, a movable block 27 made of die-cast steel (FCD 55) and hot tool steel (S

KD-61 is formed by connecting a movable core 28 made of 1) with a bonolet 29.

The movable support 23 is displaced to bring the movable mold 26 into close contact with the fixed mold 18 by displacing the movable support 23. 8, 2 6 by the product type space 3 0 for铸造, an injection passage 3 1 for emitting molten metal into the mold space ₃ 0, communicates with the mold space 30 in a different position from the injection channel 3 1 of this pressure A pressure passage 17 is formed], and 0.1 to 0.1 is set at a predetermined portion of the joint surface between the fixed die 18 and the movable die 26. There is a gap of about 5 thighs, and the injection passage 3 1])) The air in the mold space 30 0- pushed out by the injected molten metal escapes the air vent 3 3- is formed. In addition, a gate 34 is formed at the end of the injection passage 31 on the side of the mold space 30 to reduce the diameter of the passage. The supplied molten metal is injected into the mold space 30 at a high speed.

Reference numeral 35 denotes a pressure sleeve which is opposed to substantially the center of the mold space 30 and is press-fitted and fixed to the movable core 28, and is made of hot tool steel (SKD61) in a cylindrical shape. A pressure plunger 36 made of hot tool steel (SKD61) is tightly and slidably inserted into the pressure sleeve 35. A pressurizing passage 17 is formed in the space in the forward direction from the end of the pressurizing plunger 36 on the inner surface of the pressurizing sleeve 35. Then, the molten metal filled in the pressurizing passage 17 by the pressurizing plunger 36 is applied to the opposing portion of the pressurizing passage 17 in the mold space 30. 2) is pushed out to the side. The pressurized plunger 36 should be replaced only for the part that slides inside the pressurized sleeve 35 for maintenance. Composed of both members

36a and 36 are connected by a connecting ring 37. Figs. 2 and 3 show the pressure sleeve 35 and the tip of the pressure plunger 36. Figs. 9 and 32]. As shown in FIGS. 2 and 3, in the apparatus according to the present invention, the inner peripheral surface of the pressurized sleeve 35 is located at the front end side. Is larger than the other parts (for example, about 0.1 dragon). The diameter D of the large diameter part 35a is slightly larger than that of the other parts. With respect to the diameter of the pressure projector 36, it is better to determine the range of d_ + 0.05 basket <D <+ ((iX0.05) 鹧).

OMPI

'' _7. ^Wlp0 , When the pressurized plunger 36 is pressed by the presence of the large part 35a, a solidified layer formed on the outer surface of the molten metal filled in the pressurized passage u7 is removed. The thin film A enters into the minute gap 35 formed by the large diameter portion 35a]), and the thin film A is pressed into the pressurized plan. The pressurizing plunger 36 is pressurized while the outer peripheral surface of the jaw 36 is held between the outer peripheral surface of the jaw 36 and the pressurizing sleeve 35. 3 5 The inner peripheral surface is slid. Here, the length a of the large-diameter portion 35a is determined based on the amount of hot water supplied by the pressurizing plunger.] 6 is the most retracted position 35 G (the state shown in Fig. 2)] is also a predetermined amount X (10 β or less, preferably 2-3 dragons) Forward point 3 5 (1 ]) It is desirable that the length be up to the tip 35 e of the pressurized sleeve 35, that is, 35 mm at the end of the mold space 30 side. However, in practice, the length of the large diameter portion is extended to the point 35 (1 is the last retreat position 35 C of the pressure plunger 36) 9 until it is positioned slightly backward. There is no problem if the predetermined amount X is abolished, and the displacement amount of the pressure plunger 36 may be at the most advanced position 35f (the state shown in Fig. 3). The force that the tip surface of the pressure plunger 36 also protrudes from the tip 35 (1) of the pressure sleeve 35. The amount of displacement is the pressure. It is desirable to make sure that the flange 36 does not penetrate directly into the reservoir 32 of the mold space 30. If the tip of the jaw 36 penetrates a little into the tub J9 32, it is not practically problematic.

In the present embodiment, the basin j9 part 32 is a mold space 30 The part facing the pressurizing passage 17 is j. The size is the cross-sectional area of the pressurizing plunger 36 in the direction perpendicular to the traveling direction is the cross-sectional area of the pressurizing passage 17. ) Set to be bigger j? And this water pool]? Part 3 2 is usually cut after die casting! ) Removed. '

Reference numeral 38 denotes a pressure piston provided on the rear end side of the pressure plunger 36. The pressure plunger slides inside the pressure cylinder 39 to press the pressure plunger. It transfers the forward and backward displacement to the controller 36. Similarly to the injection cylinder 4, the third and fourth signal hydraulic pipes 40 and 41 are open on the pressurized cylinder 39, and the hydraulic switching valve made of a solenoid valve is opened. According to the valve 42, the hydraulic pump (not shown) is controlled.]? The input signal oil pressure is controlled to move the pressurized piston 38 forward and backward. . Then, the pressurized cylinder 39 is fixed to the side clamping plate 25 by the bonole 4-3, and moves together with the movable mold '26. It is.

In addition, the reference numeral 44 penetrates the movable block 27 and the movable core 28, and the tip of the projection faces the surface of the movable core 28 in the j-type space 30. After moving the movable mold 26 backward and opening the mold, the solidified die-cast product in the mold space 30 is pushed away from the movable mold 26]). Jig tough. Extrude via push-in rod 48, rate 45, push-out rod 46, push-out plate 47, and push-out rod 48. In response to the displacement of 49, it is displaced in the horizontal direction in the figure. The push-out port 46 is provided on the movable block 27. By sliding in the sliding hole (not shown), it is possible to move left and right in the figure. 50 is an extruder cylinder that displaces the push piston 49, and is an injection cylinder.

Like the 4 and pressurized cylinders 39, the fifth and sixth signal hydraulic pipes 51 and 52 are open.]), Hydraulic pumps (not shown)]? The input signal hydraulic pressure is controlled by a hydraulic switching valve 53 made of a solenoid valve, and the push-out piston 50 is moved forward and backward. '

Next, the die casting method of the present invention will be described in detail in the order of steps.

[First Step] The movable mold support 23 is slid to the left in FIG. 1 by driving a not-shown piston, and the movable mold 26 is brought into close contact with the fixed mold 18. Mold space for product construction

30, the injection passage 31, the pressurized passage 17 and the air vent 33 are formed.

[Second process] Using a molten metal injector (not shown), the molten metal is poured into the injection port 15 and into the injection sleeve 14 and a part of the injection passage 31, and then the hydraulic pressure is switched. The signal hydraulic pressure is supplied to the first signal hydraulic pressure passage 6 side by the bubble 9, and the injection piston 5 (in other words, the injection plunger 13) can be determined by the signal hydraulic pressure. Advance at a given pressure. Then, as the injection plunger 13 advances, the hot water poured into the injection sleeve 14 is pushed out to the injection passage .. 31 side. The molten metal is injected into the mold space 30 and the pressurized passage 17 by accelerating while passing through the gate 34 and melts in the mold space 30 and the pressurized passage 17.

OMPI

W1PO ノ Fill with hot water. The pressure (injection pressure) applied to the molten metal at this point is about 500 to 150 atm. Here, the air existing in the mold space 30 and the pressurized passage 17 is caught in the molten metal at the time of the injection and causes a dot nest. The air vent 33 provided at a predetermined part of the contact area with the air allows a part of the air existing in the mold space 30 and the pressurized passage 17 to escape. I am trying to do it.

[Third Step] After the molten metal is filled, the pressurizing plunger 36 is moved so that the molten metal in the gate 34 does not solidify, and the molten metal in the pressurizing passage 17 is moved. And push it out to the water tank j? Section 3 2 side.

Here, after the filling of the molten metal, the time until the start of the hot water (hereinafter referred to as the time lag) is long. If the time is too long [9], the molten metal filled in the mold space 30 will Coagulation occurs, and the coagulation layer generated during this time is under pressure and cannot prevent the formation of nests. The strength and airtightness may be inferior), and once the nest has formed, the solidified layer must be crushed in order to remove it. The pressurizing pressure must be set to a large value. In other words, if the pressurizing pressure is the same, increasing the time lag will result in insufficient hot water. This has been confirmed by the results of an experiment conducted by the inventor on the relationship between the time lag and the amount of hot water (illustrated in Fig. 4). ¾

OMPI

!, ,, W1FO In FIG. 4, the solid line L indicates the experimental result when the pressure was applied at a pressure of 275 OKZ c ^], and the dashed line M and the broken line N indicate 2 12 ^ H, respectively. The experimental results at a pressure of / ci ^ 1500 ^ are shown.

In addition, when the time lag is long, the solidified layer that has been formed once is subjected to pressure.] It is likely that the solidified layer will be sheared, and surface defects will easily occur in the die-cast product. Surface defects are undesirable because they degrade the mechanical strength of die cast products. In addition, the metal crystallized before pressurization is subjected to pressurization.] 3—Because it is collected at a location, segregation is likely to occur.]? Precise machining becomes difficult because it adversely affects the machinability). Figs. 5 (a) and 5 (b) are reference photographs showing the structure of a product with surface defects and the structure of a product with segregation, respectively, when the time lag is too long. It was found in the die cast products made by the die force

Therefore, in order to eliminate these surface defects and segregation, it is desirable to make the time lag as short as possible.

In this embodiment, in order to shorten the time lag, the movement start of the pressurized plunger 36 is controlled as follows. That is, when the filling of the mold space 30 and the pressurized passage 17 with the molten metal is completed, the advance of the injection bridger 13 stops.

In order to move the injection plunger 13 forward, the oil pressure in the first signal oil / pressure passage 6 supplying the signal oil pressure rises rapidly. Therefore, the hydraulic pressure in the first signal pressure passage 6 is increased.

13 ^ "

OMPI The pressure rise is detected by the pressure switch 11, and when the pressure in the passage 6 rises above a predetermined pressure, an electric signal is applied to the pressure switch 11 by the pressure switch 11. Then, when this electric signal is applied, the oil pressure switching panel 42 supplies the signal oil pressure to the third signal oil pressure passage 40. Then, immediately after the injection is completed (usually about 0.5 seconds), the pressurized plunger 36 can be advanced.

Here, in the above-described configuration, the die casting apparatus normally takes 56 seconds to complete the solidification of the molten metal in the gate 34, so that the timing of the present embodiment This is sufficiently shorter than the time required to complete the solidification of the molten metal in the gate of 34 parts. [Fourth Step] The molten metal in the pressurizing passageway '17 is pushed out into the reservoir 32 by the rapid advance of the pressurizing plunger 36. ]) The molten metal filled in the reservoir 32 of the mold space 30 is to be pressed (pressurized). Since the gate 34 is not yet solidified at the time of this pressurization, the molten metal in the pressurizing passage 17 is pressed not only by the mold space 30 but also by the injection passage 3. The flow also flows back to the outlet 1 and the outlet sleeve 14, and the molten metal in these passages 31 ゃ is also pressurized.

Therefore, the amount of hot water required for this pressurization was simply the amount required for pressurizing only the amount corresponding to the solidification shrinkage of the molten metal poured into the mold space 30_ and the pressurized ffi path17. Would be insufficient. ' The inventor of the present invention varied the amount of the hot water in various ways to obtain a density as shown in FIG. 6 when the density of the product produced based on the amount of each hot water was adjusted. In FIG. 6, the points indicated by △ indicate the density of the product manufactured by the die casting method without applying pressure, and the points indicated by 〇 indicate the density according to the method of the present invention. It shows the density of the manufactured product, that is, the density of only the remaining product constituent parts, such as the die caster trolley, 9 parts 32 and the injection passage 31 cut off. The 0 indicates the true density of the metal used in the die (in this example, an anodized aluminum alloy for die casting). Is the maximum amount of hot water that can be obtained from the area of the pressurized surface of the pressurized plunger 36 and the sliding distance of the apparatus used in this experiment.

As shown in FIG. 6, the product-density is improved in accordance with the increase in the amount of hot water until the amount of the hot water reaches the predetermined amount of 1 (the lower part is referred to as a first area 0). From the specified amount of 1 to the maximum amount of hot water. Up to this point, the product density is true density. Keep the value approximating to?], (This part is hereinafter referred to as the second area P.) The maximum amount of hot water. In terms of density, the product density is about the same as the density of the product under pressure, but the true density | 0. It can be seen that there is a large variation up to the point close to (the lower part is called the third area Q). -Here, there is a large variation in the product density in the third area Q-the maximum amount as well. _T that also shall apply in the press and if you row the hot water, presumably because the press was hot water in'll go-between actual type space 3 0 part to the pressure of the pressurized Plan di turbocharger 3 6 are Tsu Do different

Ο ΡΙ

, V. ^WiP0 In other words, if the pressure of the pressurizing plunger 36 is higher than necessary, the injection plunger 13 must be pushed back.] 9 Since the flange 13 is large enough for the pressure plunger 36, the pressure plunger 13 is pushed back when the injection plunger 13 is pushed back. The jaw 36 instantaneously reaches the mechanically determined advanceable end, and in fact, there is enough water to press the molten metal in the mold space 30, ie, pressurization. I'll do it. Therefore, the same maximum amount. When the injection plunger 13 is pushed back by the pressure of the pressurization plunger 36 and when it is pushed back even when the hot water is supplied. The product density will vary depending on the amount of solidification that has progressed at the time of pushing back and the pushing back.

Therefore, it can be seen that it is desirable that the amount of the hot water should be in the second area. ―

Then, the present inventor examined the predetermined amount ^ that is the minimum amount for entering the second region.

P 0-P

V a ①

9 0 where va is the amount of molten metal filled in the mold space 30 and the pressurized passage.

It was found that P had a relationship represented by the average density of the product manufactured by the die casting method without pressurization, indicated by the symbol in Fig. 5. In other words, the predetermined amount 1 is the pressure applied from the pressure plunger 36 side to the injection plunger.

O PI This is the amount when the pressure is applied to the pressure from the side 13 and the flow resistance of the molten metal at the gate 34], in other words, pressurization with the mold space 30 Necessary when the molten metal filled in the passage 17 and the molten metal is pressurized in the mold space 30 without being pushed back to the passage 3 1 side. That is the amount. In order to set the amount of hot water to the predetermined amount 1 obtained by the above equation, it is necessary to set the pressure of the pressurizing plunger 36 to a delicate value as described above. Necessity]), when using the method of the present invention industrially, it is necessary to set the pressure of the pressurizing bridge 36 so that sufficient pressurization can always be performed only with the predetermined amount. Therefore, the actual amount V of the practical hot water to be used must be larger than the predetermined amount 1). Also, a predetermined amount in the second area! ]) The reason why the product density is constant even when the amount of the hot water is increased is that the amount of the molten metal in the injection passage 31 and the injection sleeve 14 is constant. This is considered to be because it is used to compensate for the shrinkage. Therefore, if the pressing force of the pressurizing plunger 36 is set to the pressure at which the injection purgers 1 and 3 are not pushed back, the displacement of the pressing plunger 36 The amount of hot water supplied by the mold is used to compensate for the solidification shrinkage of the molten metal filled in the mold space 3 (X injection passage 31 and injection sleeve 14). Therefore, in theory,

P 0 P p »P

V a + ②

P 0 P 0 However, V fills the injection passage 31 and injection sleeve 4. ― The amount of molten metal, hereafter the amount of molten metal on the injection passage side and o

In some cases, the required amount is required.

However, in practice, the spigot 34 on the injection passage 31 and the injection sleeve 14 is so narrow that the molten metal on the injection passage side does not solidify sufficiently. By the way, the solidification of the molten metal in the gate of 34 parts will be completed.] And if the gate 34 is solidified, the molten metal in the injection passage will not be pressurized any more. In addition, the term -V¾ in the above equation is a practical requirement.]?

The inventor of the present invention obtained the amount of the hot water under various conditions by experiments and estimated the solidification rate of the molten metal in the injection passage 31 and the injection sleeve 14 when the gate 34 was solidified. However, in practice, when the solidification of the gate 34 is completed, only about 30 to 50% of the molten metal in the injection passage 31 and the injection sleeve 14 may be solidified. Was recognized. Therefore, in practice

P 0 — (3 p 0 P

V = V a ^ V ¾ X (0.3 to 0.5) ③

The amount of hot water determined by P 0 P 0 is the minimum amount as the actual amount of practical hot water V to be used.

However, according to the formula (3)]? In order to always use the required amount of hot water, it is necessary to obtain the maximum pressing force required from the pressing surface area and the sliding distance of the pressing plunger 36. The amount of hot water. Must be greater than or equal to this amount. This is a pressurized plunger

OMPI

. W1PO Maximum hot water volume of 3-6. Is used as the quantity obtained in equation (3), because the same problem as the problem that occurred in the third area described above would occur. Therefore, the maximum amount of hot water by the pressurized plunger 36. Is

P 0 ― 9 P 0 9

V 0 V a +

P 0 P 0, where k is the maximum feeder coefficient and a value of about 1.

The reason why the maximum hot water coefficient was set to about 1 with the amount obtained in the above and 33 o is as follows. That is, the maximum hot water volume of the device. If the pressure is too large, it is necessary to apply an excessive load to the pressurized piston 38)) Since the size of the runner 36 and the reservoir 32 must be large, it is difficult to design the equipment, and the material yield]? The ratio of the molten metal that actually solidifies in the mold space 30 out of the total molten metal injected from the Langer 13) is also desirable. Therefore, the actual amount V of hot water used for carrying out the method of the present invention is "a large amount" than the amount obtained by the formula (3), and

(It is necessary to use a small amount of hot water in the slope as calculated by the formula D.)

O 0 ― D 0 0 ― P

Y ~ — V a +-V Ί3-κ ⑤

P 0 P

'However,-E is a practical hot water person: a value between 0.3 and 1 in number. And the amount to be determined. ·

And, as you can see from the above explanation,

OMPI In order to set the volume in the second area in FIG.

It will be necessary to set the pressing force according to 36 to a predetermined value. In other words, if the pressing force is too small, sufficient hot water cannot be produced, and the state of the first area and the pressure will be large.

1) If it is too long, the injection plunger 13 will be pushed back, and it will be in the state of the third area.

Therefore, as the pressing force, at least a pressure enough to push molten metal α filled in sleeve 35 into pool J?

P min is required and this pressure P min is the injection pressure applied by the injection bridge 13! ³ . Also, a solidified layer (shown in FIG. 7) in the pressurized passage 17 and a pressurized sleeve formed as the pressurized plunger 36 is advanced. 3 5 The sliding friction resistance between the inner wall and the pressurizing sleeve 35 The inner circumference of the tip 3 5 The pressure is increased by the resistance due to the shear deformation of the solidified layer β generated at the position 位置. This is necessary], and is obtained by the following equation.

min-π r ² = Ρο π r ² + P. ■ 2 ^ r ·-β -l · 2 ^ r-~ 2

■ e ()-τ …… ⑥

Where r is the radius of the pressurizer * 36.

L is the length of the pressurized bridge 36 at the contact surface between the solidified layer formed in the pressurized passage 17 and the inner wall of the pressurized sleeve 35.

^ Indicates the pressure plunger 36 and the pressure sleeve 35

OMP1.

A, WiPO The coefficient of sliding friction between the two was 0.3 by the inventor of the present invention when measured for the device having the above configuration, and was generally in the range of 0.2 to 0.4. e (ti :) is the thickness of the solidified layer after ti seconds have elapsed after filling the pressurized passage 17.

Is the stress required to shear the solidified layer. For example, in the case of an aluminum alloy, the value is 2 to 31 ^ ^) -6). When the relationship between the time t after filling and the thickness ε of the solidified layer was examined by conducting experiments in which the values were varied in various ways, the tendency shown in Fig. 8 was observed. For example, if the time lag is 0.5 seconds, e (. T = 0 · 5) is about one recommendation. -.

In addition, when an aluminum alloy is used for the molten metal, the shear plane に is generated in a direction of 45 ° with respect to the thickness direction of the solidified layer ^, so that the shear plane r The thickness was set to ^ ~ · e (ti).

If the pressure is equal to or more than the pressure P min determined by the above equation, the pressurized plunger 36 can move forward.], But once the pressurized plunger 36 starts moving forward, the contact Since the surface length L becomes smaller, the required pressure is kept above P min.

Also, the maximum pressure Pmax is the maximum pressure in the range where the injection plunger 13 is pushed back. The pressure applied to the flange 13 is the pressure flange 36.]) The pressures Pa and D, and the molten metal passes through the gate 34 etc.

OMP1, Λ, W1PO This is a pressure obtained by subtracting the pressure drop Δ る generated at the time of injection. I just need.

That is, although the pressure at the tip of the injection plunger 13 is balanced,

p. _{7TR2 = (a- Δ) π (} E- e (t2)) 2 - - 2 ^ (Ε- £ (t2)) · 2 "· £ (Ϊ2) · r 1 ... ⑧ to However, cattle injection-flops La Radius of changer 13

The formula ③ should be J? ,

⑨ is obtained. The pressure of the molten metal pressurized by the pressurizing plunger 36! ^{Between 3} a and the maximum pressure P max of the pressurizing-brancher 36

max ■ π-r ¹ = a ^ rr ² + Pa 2 r L 'β + 2 ^π r ~ 2 ~ e (tz)

• T (t ₂ ) · ⑩

Pmax r-1 2 e (t2) τ (t ₂ )

⑪ r + 2L 'β where L' is the contact-surface length at time "b2".

Because of the relationship-

(r + 2L'i) ΔΡ, 2 ^ ε (t ₂ ) r (t ₂ )

+ r r

OMPI

, U i Is the maximum pressure of the pressurized bridge 36. When actually using the method of the present invention industrially, if the maximum pressure P max P obtained by the above equation is used, depending on the product, the pressure drop Δ Ρ and the solidification layer It is often considered that the applied pressure becomes excessive due to variations in the thickness ε, etc., so that the maximum pressure P max 'actually used is smaller than the maximum pressure P ma obtained by the above equation. There is a need to. In addition, since it is difficult to quantitatively grasp the pressure drop Δ に compared to other factors, the maximum pressure P max 'actually used is the maximum pressure P ma, let the pressure drop Δ 項 term (r + 2Lt) AP be

Calculate as the subtracted value. ,

In determining the thickness e of the solidified layer and the shear stress, according to the experiments performed by the present inventors, the time t 2 after the filling of the molten metal is determined by the pressurized planner. The time required to move to half of the sliding distance L should be used. (3) It was found that a practically approximated value was obtained.

And this way?]? The minimum pressure P min and the maximum pressure found! ^The pressurizing passage 17 is pressurized with a pressure of a predetermined magnitude between ⁵ max and at least this pressurization causes the molten metal in the mold space 30 and the pressurizing passage .17 to be pressurized. Until the solidification is completed, in other words, the gate 3 4] Continue until the mold space 30 is completely solidified o

The most characteristic feature of the present invention is that the sliding action of the pressure plunger 36 in the fourth step is performed for a long time.

O P1 In this case, the pressing force of the pressurizing plunger 36 can be maintained within the above-mentioned predetermined range.] Therefore, in the present invention, a large-diameter portion 35a as shown in FIGS. 2 and 3 is provided in the mold space 30 side portion of the pressurizing passage 17 so that the pressurizing plunger 36 moves forward. At this time, the ring-shaped solidified layer is formed in a minute gap 35 形成 formed between the outer peripheral surface on the tip end side of the pressurized plunger 36 and the inner surface of the pressurized passage 17. Pressing bridge 36 moves forward while pinching thin film A]? In addition, the solidified layer can be prevented from entering the tight fitting portion between the pressure bridge 36 and the pressure sleeve 35. This operation is described in more detail below, depending on the pressure in the pressurizing passage 17.) Since the inner diameter of the pressurizing sleeve 35 elastically expands and deforms in the pressurizing passage 17, the pressure is increased. The solidified layer of the molten metal filled in the pressure passage 17 enters the slight gap between the pressurized flange 36 and the pressurized sleeve 35. However, in practice, the forward speed of the pressurized plunger 36 is the highest at the start of forward motion.] ?, the pressurized plunger 36 in the fitting portion of the predetermined amount X in FIG. Is passing at high speed, and the solidified layer of the molten metal enters the above-mentioned slight gap! The solidified layer of the molten metal is pushed into the large-diameter portion 35a together with the pressurized plunger 36, so that there is no time allowance for the large diameter portion 35a. As shown in Fig. 3, a ring-shaped thin film A is formed on the outer peripheral side of the tip of the pressure clamp 36, and this thin film A is pressurized. Due to the pressing action of the jaw 36], the molten metal flows into a solidified solidified layer with a forged structure.

OMPI It plays a good role as a skin material to prevent protrusion, and while being sandwiched between the pressure plunger 36 and the inner surface of the large diameter portion 35a, the pressure plunger Move forward to the position shown in Fig. 3 with jumper 36. c. Prevents the solidified layer from penetrating into the tight fit between the flange 36 and the pressure sleeve 35 to prevent poor sliding of the pressure flange 36. You can.

If the predetermined amount X shown in FIG. 2 is set to a large dimension of, for example, 10 or more, the pressurized plunger 36 passes through the fitting portion of the predetermined amount X. This takes a long time, and the solidified layer invades at the fitting portion of the fixed amount X, which is preferable. Also, the fitting portion of the predetermined amount X is eliminated, and the ラ retreat position of the pressurized plunger 36. When the 35 G is set to the large diameter portion 35 a side, Since the distal end of the spring 36 enters the large diameter portion 35a from the beginning, the length of the large diameter portion of the pressure plunger 36 is increased. If too hard, the solidification layer thin film A force is cut. Therefore, one end 35 of the large diameter portion 35a (1 needs to be set near the retreat position 35 c of the pressure plunger 36)

[Fifth step] Gate 3 4] When solidification of mold space 30 is completed, hot water can be formed even if pressurization is continued by pressurized plunger 36. The signal hydraulic pressure is turned off by the hydraulic pressure changeover valve 42! ? After the change, the signal hydraulic pressure is caused to flow to the fourth signal hydraulic pressure pipe 4'1 side so that the pressurized plunger 36 is retracted. -The time required for solidification of the molten metal in mold space 30 Since the pressure varies depending on the volume and the height of the space, the time required for retreating the pressurized plunger 36 is varied in advance, and the time required for coagulation is measured. ]. After a lapse of a predetermined additional time (approximately 1 or 2 seconds) added to the obtained time, the hydraulic switching valve 42 is turned off by a ball screw [3]. Okuichi. Since the thin film A has a forged structure and is strong, and has a certain thickness, it is not cut when the pressure plunger 36 is retracted.

[Sixth step] After retracting the pressure plunger 36, the piston (not shown) is driven to move the movable support 23 to the right in FIG. 2 6 is fixed type 1 8]?

When the movable mold 26 is separated, the outer surface of the molten metal on the side of the injection passage should be solidified so as not to lose its shape. Jar 36 After retreat 0.5 to: The movable mold 26 is pulled apart in about 1.0 second.

When the movable mold 26 is separated, the signal oil pressure is still allowed to flow to the first signal pipe 6 side, and the molten metal solidified in the injection sleeve 14 is injected into the injection sleeve. So that it can be pushed out from the probe 14. ''

Thereafter, the signal hydraulic pressure is switched off by the hydraulic pressure switching valve 9 and the second signal is supplied to the pipe 7 side, whereby the injection plunger 13 is retracted. By actuating the hydraulic pressure switching valve 53, the signal hydraulic pressure is moved to the fifth signal hydraulic pipe 51 side.

ΟΜΡΙ The sink, push-out piston 49 is moved to the left in FIG. 1, and the movement of this push-out piston 49 is pushed out by the push rod 4 8, push out. The plate 47, extrude load 46, and the ejector plate 45 communicate to the ejector pin 44 via the ejector The solidified die-cast product in the mold space 30, the injection passage 31, and the pressurized passage 17 by the tapping 44 is extruded.

The die casting method of the present invention is completed by the above steps. The die cast manufactured by the die casting method has a shape as shown in FIG. Therefore, after die casting, the solidified part in the injection sleeve 14, the injection passage 31, and the air vent 33 (Fig. 9 Cut the cross-hatched area R) by pressing to remove j9, and furthermore, cut off the water reservoir section? 2 (Fig. 9: cross-hatched area S) to complete the product. Let

Here, hot water! It is possible to use part or all of part 3 2 as a product, but it is desirable to cut it for the following reasons.

That is, in the basin section 32, the hot water is directly pushed by the pressure plunger 36, and solidification proceeds in that state. The solidified layer ^ formed in the step is sheared before it grows sufficiently, resulting in surface defects. · Also, since the difference in the crystallization time of the molten metal occurs depending on the type of metal, only the first crystallized metal pools.9) Metals that are still in the molten state are pressurized. Press with 6 As a result, segregation is more likely to occur. And, as described above, this surface defect segregation adversely affects the strength and workability of the manufactured product. For products that require precision processing, it is desirable to cut the water reservoir section 3 2 ′. On the other hand, the molten metal filled in the mold space 30 is not directly heated by the pressurized plunger 36, so surface defects and segregation It is unlikely that harmful components such as will occur. FIG. 10 is a reference photograph showing the structure of the product portion solidified in the mold space 30 of the die cast product produced by the method of the present invention. It can be seen that in the product made by the method described above, no flaws, surface defects, segregation, etc. occurred. Fig. 11 shows the density distribution of the product made by the method _ of the present invention (indicated by the symbol 〇 in the figure) in the case of using both an anodized aluminum alloy as a die casting material. This is a diagram comparing the density distribution of products made with conventional die-casting without pressurization (indicated by the squares in the figure)]), and 13 6 die-cast products. The figure shows the density of each piece when cut into small pieces.) This shows how many small pieces were obtained at each density. According to FIG. 11, the density of the product obtained by the method of the present invention is improved to a value close to the true density. It can be seen that nests, which have the most adverse effect on airtightness, are almost completely blocked.

FIG. 12 and FIG. 13 show another embodiment of the present invention.

ΟΜΡΙ

W1PO A small diameter part 36 (1) having a predetermined length Z is provided at the tip of the pressure plunger 36, and the small diameter part 36 (1 and the pressure sleeve 3 A small gap 35 mm is formed between the inner and outer surfaces 5 to prevent the solidified layer from galling on the outer peripheral surface of the pressurized bridge! 6 (The diameter D 'of 1 is equal to the diameter 加圧 of the pressure plunger 36.

d— (d x o .0 5)

It is good to decide within the range.

In addition, the small diameter portion 36 is not linear, and may be formed in a slight tapered shape.

Further, the distal end surface 36C of the pressure plunger 36 is not limited to a flat surface, and can be changed to various forms such as a convex surface and a concave surface.

It goes without saying that the pressurized bridge 36 used for carrying out the method of the present invention does not have to be arranged in the movable mold 26]? It may be used on the fixed mold 18 side, or may slide on the joint surface between the movable mold 26 and the fixed mold 18.

7 Industrial Applicability According to the method of the present invention, it is possible to greatly reduce the occurrence of cavities that adversely affect the airtightness of the product and the strength of the material. : Effective for manufacturing parts requiring tightness, parts subject to high pressure, and parts requiring precision processing. J, for example, a compressor or pump housing

O PI It can be used as a manufacturing method for

OMPI

Claims

Scope

1. The close proximity of a plurality of molds creates a mold space for product production, an ejection passage that opens one end into this mold space and guides the molten metal into the mold space, and an ejection passage. And a pressurized S path communicating with the mold space at a different position from the mold space, and injecting molten metal into the mold space and the pressurized passage at a predetermined pressure. The mold space and the pressurizing passage are filled with the molten metal, and thereafter, the pressurizing plunger in the pressurizing passage is advanced to advance the pressurizing. In a die casting method in which the molten metal in the passage is pushed out to press the molten metal in the mold space, the molten metal is pressurized by the advance of the pressurized flanger. When applying the pressure, A pressure layer is sandwiched between a layer of molten metal in a minute gap between the outer peripheral surface on the tip end side of the noher and the inner peripheral surface of the pressurizing passage. Dikas specializing in advancing the ranger

2. By bringing several molds close together) The mold space for product formation to be formed,

One end opens into this mold space and an injection passage that guides the molten metal into the mold space.

A pressurizing passage communicating with the mold space at a different position from the injection passage;

In this case, the molten metal in the above-mentioned mold space is tightly and slidably inserted into the pressurizing passage, and is extruded from the molten metal filled in the pressurizing passage. A pressure plunger and a A large-diameter portion formed on the inner surface of the pressurizing passage from the end of the pressurizing passage on the side of the mold space to the vicinity of the last retreat position of the pressurizing blower. Die casting device.

3. A claim according to claim 2, characterized in that the most advanced position of the pressure plunger is restricted to a range that protrudes from the mold space side end of the large diameter mold. Die casting equipment.

4. The diameter D of the large diameter portion with respect to the diameter d of the pressure

d + 0.05 Fiber <1) <<1 + (dX0.05)) The die according to claim 2 or 3, characterized in that it is set in the range of 騮. Casting device.

5. The mold space for product structure formed by bringing multiple molds into close contact with each other:

One end opens into this mold space, and an injection passage that guides the molten metal into the space.

A pressure passage communicating with the mold space at a different position from the injection passage; and

A pressurizing blower that is tightly and slidably inserted into the pressurizing passage and pressurizes the molten metal in the mold space by extruding the molten metal filled in the pressurizing passage. And a die casting having a predetermined length formed at the tip end side of the pressurizing bridge.