JPH07112614B2 - Die casting device and die casting method - Google Patents

Description

The present invention relates to a die casting device and a die casting method,
It is particularly effective when used for die casting of products having complicated shapes.

[Conventional technology]

As a method of die casting a product with a more complicated shape than before, press the molten metal filled in the product cavity with a squeeze plunger before the molten metal solidifies,
It has been known to suppress the formation of nests in the molten metal (Japanese Patent Publication No. Sho 59-13942, Japanese Patent Publication No. 59-30503, and Japanese Patent Publication No. 58-5).
5858 and Japanese Patent Publication No. 60-2947).

In this conventional method, as shown in FIG. 15, a squeeze plunger 103 is disposed on either the fixed die 101 or the movable die 100, and the molten metal is pressed by the squeeze plunger 103.

The conventional method shown in FIG. 15 is excellent for casting a complex shape of a thick product, and can also suppress the occurrence of shrinkage cavities and the like.

However, due to changes in the environment in which die cast products are used in recent years, even the die cast products produced by this conventional method have become problematic in the generation of entanglement nests that cannot be prevented. In particular, when heat-treating a die-cast product, the minute entrapped cavities trapped in the die-cast product expand due to heating, causing the product's outer shape to deform significantly, and requiring a precise system. In some cases, there was the problem that the dimensions were not stable after heat treatment.

The inventors of the present invention have examined the die-cast product produced by the conventional method, in particular, regarding the state of occurrence of a entanglement nest. As a result, it has been found that an entanglement nest 200 is formed around the portion facing the squeeze plunger 103. Figure 16 shows the state before pressing the molten metal with the squeeze plunger,
An entrainment nest 200 is generated around the portion facing the squeeze plunger 103. This is a squeeze plunger 103
It is recognized that the mold release agent 201 sprayed toward the tip side of the squeeze plunger 103 to secure the slidability of the sheet has a great influence on the occurrence of the entrapment nest 200.

Therefore, the inventors measured the effect of the release agent 201 sprayed on the squeeze plunger 103 on the entanglement nest 200 by an experiment. The present inventors did not spray a large amount of lubricant to the squeeze plunger 103 side as shown in FIG. 15, but apply a minimum release agent to the tip of the squeeze plunger 103 and perform die casting in that state. did. As a result, in the case where the amount of the release agent is minimized in this way, the entanglement nest 200 generated in the die cast product is significantly reduced, and even if the die cast product is heat-treated, its precision is not adversely affected. Was confirmed. However, it was confirmed that the squeeze plunger 103 had a sliding failure. If the release agent is applied to the tip of the squeeze plunger 103 with a brush, the die casting process is
After repeating 20 to 20 times, it was confirmed that the squeeze plunger 103 had a sliding failure. Moreover, even when the squeeze plunger 103 is brushed with a mold release agent every time the die casting process is performed about 20 times to prevent sliding failure on the squeeze plunger 103 and die casting is performed, the squeeze process is performed. It was recognized that the plunger can last its life through the die casting process of 300 to 700 times.

As described above, according to the experimental study by the present inventors, although the amount of the release agent applied to the squeeze plunger has many influences on the occurrence of the entanglement nest 200, the release agent is the squeeze plunger 103. It was confirmed to be particularly important for maintaining life.

Here, the release agent is not limited to the squeeze plunger 103,
It is also required for the inner surfaces of the fixed mold 101 and the movable mold 100. However, the large diameter portion of the tip portion of the squeeze plunger 103 and the tip portion of the squeeze cylinder 107 has a narrow gap formed in a ring shape, and the amount of the release agent supplied to sufficiently attach the release agent to both surfaces is , Other fixed type 10
1 and the amount of release agent supplied to the movable mold 100 must be significantly higher. The amount of the release agent supplied to the large diameter portion of the tip of the squeeze plunger 103 and the tip of the squeeze cylinder 107 was set to be approximately the same as the amount of the release agent supplied to the other fixed mold 101 and movable mold 100. Therefore, it is recognized that the squeeze plunger 103 immediately causes a sliding failure. This is because the squeeze plunger 103 is extruded toward the molten metal side in a state where the product cavity 105 is filled with the high-pressure and high-temperature molten metal, and therefore its lubricity is particularly required.

In other words, in the die casting method, if the use of the squeeze plunger 103 is stopped, it is not necessary to spray a specific amount of the release agent. However, in this case, since the pressing by the squeeze plunger is not performed, the product density of the entire die cast product is reduced.

FIG. 17 shows an example of the effect of pressing by the squeeze plunger. As is clear from FIG. 17, the die-cast product 300 that is not pressed by the squeeze plunger 103 is the die-cast product 3 that is pressed by the squeeze plunger 103.
It is confirmed that the product density is lower than that of 01.

[Problems to be Solved by the Invention]

The present invention has been devised in view of the above-mentioned points, and while the molten metal is pressed by the squeeze plunger in die casting, the amount of the lubricant supplied to the squeeze plunger is accurately controlled to ensure the slidability of the squeeze plunger. In addition, the purpose of the present invention is to suppress the occurrence of entanglement cavities and the like due to the lubricant.

In order to achieve this object, the present inventors first focused on ensuring that the lubricant is sprayed onto the squeeze plunger. FIG. 18 shows the contents proposed by the present inventors. In this figure, an annular groove 310 is formed in the squeeze cylinder 107, and the lubricant is squeezed from the annular groove 310 by the squeeze plunger 1
03 It is designed to blow out toward the tip. As a result, a lubricating film 311 is formed on the tip of the squeeze plunger 103.

However, in the apparatus shown in FIG. 18, the squeeze cylinder 107 tip portion 308 is not always sufficiently lubricated, seizure occurs, and the die cast product becomes squeeze cylinder 10
There is a problem that it is difficult to extrude than 7 and the die casting machine stops.

FIG. 19 also shows the contents proposed by the present inventors.
In the illustrated example, a lubricant spray hole 312 is formed at the tip of the squeeze cylinder 107, and the lubricant is sprayed from the spray hole 312 toward the tip of the squeeze plunger 103. However, in the example shown in FIG. 19, the molten metal flows into the tip portion of the lubricant spray passage 312,
A defect was found that blocked the passage 312.

The present invention employs a configuration in which a lubricant passage for guiding the lubricant to the tip portion of the squeeze plunger is formed inside the squeeze plunger based on the result of the above examination. The lubricant is sprayed from the back of a predetermined annular space formed between the tip of the squeeze plunger and the large-diameter portion of the tip of the squeeze cylinder from a lubricating passage formed in the squeeze plunger.

[Action]

With the above configuration, the lubricant is directly sprayed on both the large-diameter portion at the tip of the squeeze cylinder and the squeeze plunger, and the sprayability is improved. That is, the lubricant is blown toward the tip from the back of the narrow annular space between the outer peripheral surface of the tip of the squeeze plunger and the inner surface of the large diameter portion of the tip of the squeeze cylinder, so that the gap is surely filled with the lubricant. As a result, the lubricant is surely attached to both the squeeze plunger and the large diameter portion at the tip of the squeeze cylinder, and the amount of lubricant used can be kept small.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a die casting apparatus, and in the figure, 401 is a fixed platen, which is fixed on an apparatus base (not shown). 400
Is a movable platen, which can be moved in the left-right direction on the device base. A fixed die 101 is fixed to the fixed platen 401, while a movable die 100 is fixed to the movable platen 400. In the present embodiment, the injection cylinder 120 is provided on the fixed mold 101 side, and the injection cylinder 120
An injection plunger 121 is slidably arranged therein.
A molten metal inlet 122 is opened at a position where the injection plunger 121 is displaced to the rear end side (right side in the figure).

On the movable mold 100 side, a plurality of push-out pins (not shown) are arranged so as to project toward the product cavity 105. A squeeze cylinder 107 is arranged on the movable die 100 so as to be directly exposed to the product cavity 105, and a squeeze plunger 103 is slidably arranged in the squeeze cylinder 107. A pressure piston 410 is formed at the rear end of the squeeze plunger 103, and the pressure piston 410 is slidably arranged in the pressure cylinder 411. The hydraulic pressure supplied to the pressurizing cylinder 411 is switched and controlled by the control valve 420. Product cavity 1
A pressurizing piston 421 is also formed at the rear end of the cutoff pin 130 that opens and closes a passage 501 connecting the 05 and the vacuum exhaust device 500, and this pressurizing piston is also slidably arranged in the pressurizing cylinder 422. Set up. Then, the forward / backward movement of the cutoff pin 130 is switchably controlled according to the hydraulic pressure from the control valve 420.

A spool core 140 is formed so as to project toward the injection cylinder 120 side at a position facing the injection cylinder 120 in the movable mold 100. The spool core 140 guides the molten metal injected from the injection cylinder 120 to the product cavity 105 side. Therefore, the spool core 140 is a part that the molten metal directly collides with, and is a part that has the highest temperature in the fixed mold 100. A lubricating pin 150 is arranged on the spool core 140. The lubricating pin 150 sprays the lubricant together with the high pressure air onto the spool core 140 side. In this example, the lubricating pins are arranged at three places so as to surround the spool core 140 (only one lubricating pin 150 is shown in FIG. 1).

As shown in FIG. 2, a lubricant passage 153 is also formed inside the squeeze plunger 103. The lubricant passage 153 is branched into six points on the side surface of the squeeze plunger 103, and when the squeeze plunger moves forward (state of FIG. 2).
An open end 154 is arranged so as to open in a gap 156 of about 1 mm formed by the large diameter portion 155 of the tip portion and the squeeze plunger 103. As shown in FIG. 3, the opening end 154 of the lubricant passage 153 blows out the lubricant and air from the back of the space 156 toward the large squeeze diameter portion 155 and the tip of the squeeze plunger 103. Also, the lubricant passage opening end 15
The diameter d of 4 (shown in FIG. 6) is about 2 mm in this example. Here, the reason why the diameter is about 2 mm is that if the diameter d is too small, the passage opening end 154 may be clogged by the residue of the lubricant. Also, if the diameter d is made too large, the flow velocity of the lubricant sprayed to the gap 156 side becomes small.

As described above, the open end 154 has the squeeze plunger 103.
Are formed at six locations on the circumferential surface at equal intervals in the circumferential direction.
This is so that the lubricant blown out from the open end 154 can be uniformly distributed over the entire outer surface of the squeeze plunger 103. The lubricant blown out from the opening end 154 needs a sufficient flow velocity, but if the flow velocity is to be secured, the distribution angle of the lubricant blown out from the opening end 154 becomes narrow. Therefore, in this example, the number of the open ends 154 is set to 6 so that both the flow velocity of the lubricant blown out from the open ends and the distribution of the lubricant can be achieved.

The lubricant passage 153 communicates with the passage 160 as shown in FIG. 1, and the lubricant in the lubricant tank 170 is supplied through the main passage 160. The amount of lubricant supplied to the lubricant passage 160 is adjusted by the metering valve 161. In this example, the amount of lubricant blown out from the squeeze plunger 103 is about 0.1 cc each time, so this metering valve is highly accurate with a variation of about 0.005 cc / time.

The lubricant supplied to the lubrication pin 150 is also accurately metered by the metering valve 162. The lubricant is supplied to the lubrication pin 150 via the lubrication passage 163. In this example, the amount of lubricant supplied to the lubricating pin 150 side is about 2.5cc to 3cc per time. A pump 171 is provided on the upper surface of the tank 170, and the lubricant 201 in the tank 170 is supplied to the metering valves 161 and 162 by this pump.

Further, although not shown, a high-pressure air passage communicates with the lubricating pin 150 and the squeeze plunger 103. Therefore, the lubricant supplied from the lubricant passages 160 and 163, together with the high-pressure air, flows into the squeeze plunger 103 and the lubricating pin 150. It will be sprayed from the opening end.

Next, a die casting method using the apparatus having the above configuration will be described.

First, the lubrication process will be described. In this lubrication process,
The movable die 100 moves leftward in FIG. 1 together with the movable platen 400, and the product cavity 105 is opened. In this state, as shown in FIG. 3, the squeeze plunger 103 receives the hydraulic pressure in the pressure cylinder 411 and moves forward. The squeeze plunger 103 will advance to the position where the open end 154 of the lubricant passage 153 opens deep inside the gap 156 (state of FIG. 2). In this state, the high pressure air passage (not shown) is opened and 4
Air of about atmospheric pressure is blown out toward the open end 154 in the lubricant passage 153. At this time, a predetermined amount (0.1 cc) of the lubricant metered by the metering valve 161 is applied to the lubricant passage 1
It is supplied to 53 and thus blown out through the open end 154 with the high pressure air. In this example, the lubricant 201 is a liquid lubricant containing silicon oil or the like.

The lubricant is sprayed from the open end 154 to the squeeze plunger 103 tip and the squeeze cylinder tip large diameter portion 115, and fills the space 156. On this occasion,
Since the squeeze cylinder 107 and the squeeze plunger 103 are heated to a high temperature due to the heat of the previous die casting, the oil and water in the lubricant must be evaporated by the heat of the squeeze plunger 103 and the squeeze cylinder 107. become. Then, the vaporized components are influenced by the blowing of the high-pressure air and blown out to the outside.
In this state, since the fixed mold 101 and the movable mold 100 are separated from each other, the evaporated component is blown out to the outside of the product cavity 105.

In this lubrication process, the lubrication pin 150 also projects from the movable die 100, and the lubricant 201 is sprayed toward the spool core 140. Lubrication pin 150 is also the above squeeze plunger 1
Similar to 03, the lubricant is blown out by receiving the air flow of high pressure air. In this example, three lubricating pins 150 are provided.
The total amount of lubricant ejected from the lubrication pin 150 of the book is 2.5 cc
It is about 3.0cc. As described above, the amount of the lubricant blown out from the lubricating pin 150 is larger than that of the lubricant blown out to the squeeze plunger 103, but the spool core 140 has a higher temperature than the pressure plunger 103 portion. Therefore, this lubricant can be vaporized well. Therefore, oil and water are evaporated from the lubricant 201, and the lubricant component such as silicon oil becomes a lubricant film and is applied onto the spool core 140. At this time, the evaporated oil and water are blown out of the mold as in the case of the lubricant on the squeeze plunger 103 side.

After the lubrication is completed, the squeeze plunger 103 receives the hydraulic pressure of the pressure piston 410 and the pressure cylinder 411 and is drawn into the squeeze cylinder 107. At the same time, the lubrication pin 150 and the cutoff pin 130 are also connected to the pressure cylinder 422.
It is retracted into the movable mold 100 by receiving the pressure inside. Further, during the lubrication process, the injection plunger 121 is retracted rightward in FIG.

Next, the cavity forming step will be described.

The movable platen 400 and the movable die 100 are displaced rightward in FIG. 1 by receiving the pressing force of a hydraulic cylinder (not shown). Due to this displacement, the movable die 100 comes into contact with the fixed die 101, and a product cavity 105 is formed between them.

After the product cavity 105 is formed, the injection plunger 121
Has retreated to the right in FIG. 1, and the molten metal inlet 122 is open in this state. Therefore, a molten metal such as an aluminum alloy is injected into the injection cylinder 120 through the injection port 122. Then, the injection plunger 121 is immediately advanced by a hydraulic cylinder (not shown), and the injection plunger 121 is stopped when the injection plunger 121 is advanced to a predetermined position. Injection plunger 121
The vacuum evacuation device (vacuum pump) 500 operates in a state in which the air is stopped, and the air in the product cavity 105 is exhausted through the exhaust passage 501. By the action of this vacuum pump, the pressure inside the product cavity is evacuated to a predetermined pressure.

After the evacuation is completed, the injection process is started. Immediately, the injection plunger 121 is advanced at high speed by a hydraulic cylinder (not shown). By this forward movement, the molten metal in the injection cylinder 120 is injected toward the spool core 140. Therefore, the injected molten metal first collides with the spool core 140 and then flows toward the product cavity 105 side.

Here, since the spool core is coated with the lubricant sprayed by the above-described lubrication process, this lubricant is wound up when the molten metal collides, and then flows into the product cavity 105 side prior to the molten metal. . Therefore, the lubricant applied to the spill core 140 is supplied to the product cavity prior to the molten metal and applied to the inner surfaces of the fixed mold 101 and the movable mold 100. In this way, the product cavity 105 can be filled with the molten metal while supplying the lubricant.

Next, the squeeze process will be described.

As shown in FIG. 2, an inlet portion 471 having a narrow cross-sectional area between the spool core 140 portion and the product cavity 105.
Are formed. By narrowing the molten metal injection passage by the inlet 471, the molten metal can be rapidly fed into the product cavity 10.
This is to inject within 5.

After the molten metal is filled in the product cavity 105, the molten metal is first solidified at the inlet portion 471 where the passage area is small.

The squeeze plunger 103 is pushed out to the product cavity 105 side before the solidification at the inlet 471 is completed. That is, when the injection plunger 121 is displaced, the control valve 420 switches the hydraulic pressure after a predetermined time, and pushes the pressurizing piston 410 to the right in FIG.

At the pushing position of the squeeze plunger 103,
As shown in the figure, the molten metal 550 is filled in the product cavity 105.
A solidified layer 551 is formed on the surface. Therefore, the squeeze plunger 103 is pushed out toward the product cavity 105 side so that the solidified layer 551 is rolled up. In any case, since the squeeze plunger 103 advances in the state where the molten metal 550 exists, the molten metal 550 is satisfactorily pressed. Moreover, the pressurization by the squeeze plunger 103 is continued until the solidification of the molten metal 550 is completed as shown in FIG. 5, so that the shrinkage cavities generated during the solidification can be suppressed very well. As shown in FIG. 5, the squeeze plunger 103 has a slit 15 at the opening end 154 of the lubricant passage.
The amount of forward movement is specified until it is not exposed within 5. This prevents the opening end 154 from being blocked by the alloy in the void 156.

As described above in the lubrication process, since a proper lubricant film is formed at the tip of the squeeze plunger 103, the squeeze plunger 103 slides during this squeeze process and the next process, which is the take-out process. The displacement will be good. In this example, not only is the sliding displacement of the squeeze plunger 103 improved in this way, but the occurrence of entrapment cavities and the like due to the lubricant is suppressed. This effect will be described later.

Next, the take-out step will be described. Product cavity 10
After the solidification of the molten metal in 5 is completed, the movable platen 400 and the movable die 100 are displaced leftward in FIG. 1 by the driving force of a hydraulic cylinder (not shown). At the same time, the squeeze plunger 103 receives the displacement of the pressure piston 410 and is pulled back into the squeeze cylinder 107. After that, the push pin and the lubricating pin 150 (not shown) are projected to the product cavity 105 side. This extrusion pin and lubrication pin 1
By moving 50, the die cast product can be removed from the movable die 100, and the removed die cast product is taken out from the product cavity 105 by a carrying device (not shown).

The die-casting process is performed by performing the above-mentioned steps in series, and then the process is succeeded to the next die-casting process. FIG. 20 is a diagram showing one cycle step of this method.

Next, the lubricant supplied to the squeeze plunger 103, which is a main part of the present invention, will be described. As described above, in this example, 0.1 cc of the lubricant is sprayed once from the deep part of the space 156 between the squeeze plunger 103 and the large diameter part at the tip of the squeeze cylinder 107. This 0.1
cc is a value determined based on the experimental study by the present inventors.

FIG. 7 shows the relationship between the amount of lubricant, the sliding force of the squeeze plunger, and the amount of gas that represents the amount of entrapped cavities formed in the portion facing the squeeze plunger in the die cast product. In the figure, the solid line X represents the amount of gas contained in the die cast product, and the solid line Y represents the squeeze plunger sliding resistance. As is clear from this figure, when the amount of lubricant used is increased, the amount of gas contained in the die cast product increases. Here, if the amount of gas present in the die cast product is 2.5 cc / 100 g Al or more, the entrapment cavity generation amount becomes remarkable, and especially when heat treatment etc. is applied to the die cast product, the die cast product is expanded due to the expansion etc. The dimensional accuracy of can not be guaranteed. Therefore, when heat-treating a die cast product, the limit gas amount must be 2.5 cc / 100 g Al or less. It is desirable that the amount of the lubricant supplied to the squeeze plunger 103 should be 0.25 cc / cycle or less so that this standard can be sufficiently satisfied.

However, if the amount of lubricant 201 used is reduced too much,
The force required for the squeeze plunger 103 to slide suddenly increases, making it impossible to perform stable squeeze pressurization. As is clear from FIG. 7, it was confirmed that when the amount of the lubricant 201 used was 0.075 cc / cycle or less, the resistance force required for the squeeze plunger 103 to slide suddenly increased, which was not practical.
When the sliding resistance is increased, the die-cast product will have a shrinkage cavity due to the sliding failure of the squeeze plunger 103, and further problems such as galling of the squeeze plunger 103 will occur. Therefore, in this example, the amount of the lubricant 201 supplied to the squeeze plunger 103 is desired to be 0.08 cc / cycle or more in order to achieve the limit sliding force of 100 kgf or less.

Based on the above factors, the amount of lubricant 201 used in this example is 0.1 cc / time, but if the amount of lubricant used is set in this way, regardless of the long-term use of die casting. It was confirmed that the gas amount and sliding force could be kept below the limit values. FIG. 8 shows changes in the amount of gas and the sliding force as the number of castings increases. As shown in FIG. 8, even if the number of castings is increased, the sliding force of the squeeze plunger 103 and the amount of gas contained in the die cast product are It was confirmed that it hardly changed.

According to the results of use by the present inventors, it has been confirmed that the die casting plunger 103 can withstand 20,000 or more die castings.

Further, since the sliding force of the squeeze plunger 103 can be reduced, the amount of forward movement of the squeeze plunger 103 can be reliably controlled. FIG. 9 shows the effect of this forward movement amount control. FIG. 9 (A) shows the amount of advance of the squeeze plunger 103 in die casting using the lubricant spraying process of this example. In this case, the squeeze plunger 103 is controlled by the pressurizing piston 410 so that the amount of advance thereof is 17 mm. Then, as shown in FIG. 9 (A), the forward movement amount of the squeeze plunger 103 is 1 in almost all cases.
When it was stored in 7 mm ± 1 mm and the amount of advancement deviated more than 17 mm ± 1 mm, it was not recognized even once in 100 times of die casting process.

On the other hand, FIG. 9 (B) shows the amount of forward movement of the squeeze plunger 103 in the conventional die casting method shown in FIG. In the example shown in FIG. 15, since the lubricant 201 is not directly sprayed as described above, the amount of the lubricant supplied to the squeeze plunger 103 is not held constant. As shown in FIG. 9 (B), even if the pressurizing piston 410 is controlled so that the forward movement amount of the squeeze plunger 103 is 15 mm, the actual displacement amount may vary widely from 10 mm to 19 mm. become.

As described above, according to the die casting apparatus of this example, it is recognized that the amount of the lubricant supplied to the squeeze plunger 103 is always controlled to be constant, and as a result, a good squeeze process is achieved.

Furthermore, the inventors of the present invention analyzed the components of the portion of the die cast product facing the squeeze plunger 103 in order to check whether or not the lubricating oil was reliably retained on the outer surface of the squeeze plunger 103 and the inner surface of the squeeze cylinder tip large diameter portion 115. went. This component analysis is based on the solidified layer surface 555 in FIG.
Component analysis of Fourier-transform infrared spectroscopy (Fourier-trans-
Form Infrared Spectroscopy) (FT-IR). Figure 10 shows the results of this experiment. In FIG. 10, the horizontal axis represents the wavelength of the absorption spectrum and the vertical axis represents the transmittance. Further, in FIG. 10, the solid line K shows the components of the lubricating film on the solidified layer surface 555, the solid line L shows the wavelength distribution state when the lubricant is heated to 350 degrees, and the solid line M shows the current state of the lubricant. The following shows the wavelength distribution state. This solid line L, M
As is clearer, the lubricant 201 has a CH ₃ group (a in the figure),
SiCH ₃ groups (b in the figure), CO groups (c in the figure) and CH groups (d in the figure) were observed, and the same wavelength peaks were also observed from the surface of the solidified layer. Therefore, from this component analysis result, it can be confirmed that the lubricant has surely adhered to the outer surface of the squeeze plunger 103 and the inner surface of the squeeze cylinder set large diameter portion 115.

As described above, in the die casting apparatus of this example, the space between the squeeze plunger 103 and the squeeze cylinder tip large diameter portion 115 is
The lubricant 201 can be accurately supplied to the 156, which also means that the large diameter portion 1 of the tip of the squeeze cylinder 107 is used.
It is also affected by the shape of 55. Here, in this example,
Although the width of 156 is about 1 mm, the shape of this slit portion is also determined by the present inventors' experimental studies. First
11 to 13 show a squeeze cylinder 107 in which the shape of the squeeze cylinder large diameter portion 155 is variously changed. And
FIG. 14 shows the number of times that continuous use is possible when die casting is performed using the squeeze cylinder 107 having each of these shapes. First
In FIG. 14, the shape is the squeeze cylinder 107 having the shape shown in FIG. 1, the shape is the squeeze cylinder 107 having the shape shown in FIG. 12, and the shape is shown in FIG. It is a squeeze cylinder 107 having a shape.

As is clear from FIG. 14, the thickness of the void 156 is 1.0 mm.
Sufficient durability was confirmed even in the die casting process of 5000 times or more, but with the slit thickness of 0.5 mm and 0.1 mm, the squeeze plunger 103 slides poorly within 50 times of die casting. There has occurred. It is considered that this is because when the thickness of the void 156 is thin, the lubricant 201 does not spread sufficiently through the void 156.

Therefore, in the die casting apparatus in this example, the thickness of the void 156 is defined as 1.0 mm as described above. In addition,
If the gap 156 is made too large, the lubricant will be the outer surface of the tip of the squeeze plunger 103 and the squeeze cylinder 1.
07 It becomes difficult to adhere to the inner surface of the large-diameter portion of the tip, and the squeeze plunger 103 pressurization process cannot be performed well.
Further, as described above, the squeeze plunger 103 has the solidification layer 5
Since it moves forward while pressing 51 (shown in FIG. 4), the forward movement of the squeeze plunger 103 cannot be well controlled in the state where the thickness of the void 156 becomes too large and the solidified layer 551 does not occur. Because.

However, in the present invention, the thickness of the void 156 should not be limited to 1.0 mm, and the squeeze plunger 103
The range that does not affect the displacement can be set appropriately.

Further, the present invention is not limited to the above-mentioned example, and it goes without saying that there are various modes.

For example, the shape of the lubricant passage opening end 154 is not limited to the circular shape described above, and may be an oval shape or a triangular shape, as a matter of course. Further, the lubricant passage opening end 154 does not have to open in the same plane, and the squeeze plunger 10
The opening may be formed at a position slightly displaced in the axial direction of 3.

Further, in the example shown in FIG. 11, the slit 155 of the squeeze cylinder 107 is provided with an inclination, but this inclination is not always necessary.

Further, in the example shown in FIGS. 3 to 6, the squeeze plunger is used.
Although the tip end surface of 103 is spherical, this tip end surface may be flat or may be concave if necessary.

Further, although the squeeze cylinder 107 is arranged in the movable die 100 in the above-mentioned example, it may be arranged in the fixed die 101 skin. In the above example, the squeeze cylinder 107 is formed separately from the movable die 100.
The 07 may be integrally formed as a part of the movable mold 100. If necessary, ribs or the like may be formed on the squeeze cylinder large diameter portion 155.

Furthermore, in the above example, the injection cylinder 120 is arranged on the fixed mold 101 side, but this injection cylinder 120 may be arranged on the movable mold 100 side.

Further, in the above-mentioned example, the lubricant supplied from the squeeze plunger 103 and the lubricating pin 150 is a liquid lubricant mixed with high-pressure air, but, for example, fine particles of a solid lubricant may be supplied, or Lubricant vapor may be supplied.

Furthermore, in the above-described example, as shown in FIG. 3, the squeeze plunger 103 is stopped from advancing and lubrication is performed in this state. However, the lubricant is blown out from the lubricant passage opening end 154. It may be performed in any state such as during the forward movement or backward movement of 103, or during the intermediate stop during forward movement or backward movement.

Further, in the above-described example, the release agent is supplied to the fixed mold 101 and the movable mold 100 by spraying a lubricant on the spool core 140, but the release agent is directly applied to the mold surfaces of the fixed mold 101 and the movable mold 100. May be sprayed.

Further, in the above-mentioned example, the product cavity 105 is evacuated, but this evacuation is not always essential and may be stopped if necessary.

Further, in the above example, the squeeze plunger 103 and the lubricating pin 1
The same lubricant is supplied to 50, but different lubricants may be supplied by independent devices.

〔The invention's effect〕

As described above, according to the die casting apparatus and the die casting method of the present invention, it is possible to reliably supply the lubricant required for pressurizing the squeeze plunger, so that it is possible to prevent sliding failure of the squeeze plunger and to perform lubrication. The amount of agent can be minimized. As a result, it is possible to extremely favorably prevent the occurrence of entrapment cavities due to the lubricant.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a die casting apparatus according to the present invention, FIG. 2 is a sectional view schematically showing the movable die and fixed die parts of FIG. 1, and FIGS. 3 to 5 are squeeze. FIG. 6 is a cross-sectional view showing displacement of the plunger, FIG. 6 is a cross-sectional view of the squeeze plunger shown in FIG. 1, and FIG. 7 is included in the amount of lubricant used in the device shown in FIG. 1, sliding resistance of the squeeze plunger, and die cast product. Explanatory diagram showing the relationship of the gas amount,
FIG. 8 is an explanatory diagram showing the relationship between the number of castings, the change in sliding resistance of the squeeze plunger with time, and the change in the amount of gas contained in the die cast product with time. FIG. 9 shows the relationship between the present lubrication method and the conventional method. Explanatory diagram showing change ratio of squeeze plunger advance amount, FIG. 10 is an explanatory diagram showing composition analysis of lubricant and lubricating film of squeeze portion, and FIGS. 11 to 13 show large diameter portion of tip of squeeze cylinder respectively. Sectional views, FIG. 14 is an explanatory view showing the relationship between the squeeze cylinders shown in FIGS. 11 to 13 and the number of times of continuous use, FIG. 15 is a sectional view showing a conventional die casting apparatus, and FIG. 16 is shown in FIG. Fig. 17 is a cross-sectional view showing a state in which a entanglement nest is generated by the die-casting device, Fig. 17 is a diagram showing the influence of the presence or absence of a squeeze on the specific gravity of the die-cast product,
FIG. 18 and FIG. 19 are cross-sectional views showing the main part of the die casting apparatus devised by the present inventors on the way to the completion of the present invention, and FIG. 20 is an explanatory view showing one cycle process of the present method. 100 …… Movable type, 101 …… Fixed type, 103 …… Squeeze plunger, 105 …… Product cavity, 107 …… Squeeze cylinder, 120 …… Injection cylinder, 121 …… Injection plunger, 150…
… Lubrication pin, 153 …… Lubrication passage.

Front Page Continuation (72) Inventor Sumi Yoshikawa, 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Hiromi Takagi, 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihondenso Co., Ltd. (72) Inventor, Mitsuyoshi Yokoi, 1-1, Showa-cho, Kariya city, Aichi Prefecture (56) References JP-A-61-20654 (JP, A) JP-A-62-220265 (JP, A) JP 60-238074 (JP, A) Actual public 49-29215 (JP, Y1) JP 60-2947 (JP, B2) JP 50-4610 (JP, B2) JP 56-6824 (JP, B2) S.K. Sho 58-28687 (JP, Y2)

Claims (6)

[Claims] 1. A fixed die, a movable die which abuts on the fixed die to form a product cavity together with the fixed die, and an injection which is formed on at least one of the fixed die and the movable die and communicates with the product cavity. A cylinder, an injection plunger slidably disposed in the injection cylinder for injecting molten metal in the injection cylinder toward the product cavity, and at least one of the fixed die and the movable die, A squeeze cylinder that is directly opposed to the product cavity; and a squeeze plunger that is slidably disposed in the squeeze cylinder and presses the molten metal flowing into the squeeze cylinder toward the product cavity side. Has an inner diameter approximately the same as the outer diameter of the squeeze plunger, and A sliding contact portion that slides on an outer wall surface, and a large-diameter portion that has an inner diameter that is slightly smaller than the outer diameter of the squeeze cylinder and that is formed over a certain distance from the opening end on the product cavity side, The squeeze plunger has a lubricant passage therein through which a lubricant flows. One end of the lubricant passage is opened to an outer peripheral wall of the squeeze plunger, and the squeeze plunger projects toward the product cavity side at an opening end. At this time, the die-casting device is characterized in that an opening is made at a portion of the annular space formed between the inner wall of the large diameter portion of the squeeze cylinder and the outer wall of the squeeze plunger on the side opposite to the product cavity. 2. The die casting apparatus according to claim 1, wherein the stationary die is provided with a vacuum exhaust device for exhausting air in the product cavity. 3. A lubricant passage inside which a lubricant flows is provided,
The die casting machine according to claim 1 or 2, wherein one end of the lubricant passage is provided in the movable die with a lubricating pin opening toward a passage connecting the injection cylinder and the product cavity. 4. A fixed die, a movable die that contacts the fixed die to form a product cavity together with the fixed die, an injection plunger that injects molten metal into the product cavity, and a squeeze that opens toward the product cavity. A die casting method using a squeeze plunger that slides in a cylinder and pressurizes the molten metal filled in the product cavity, wherein the squeeze plunger is attached to the product cavity with the fixed die and the movable die separated from each other. To form a ring-shaped space between the outer wall of the squeeze plunger and the inner wall of the squeeze cylinder at the opening end face portion of the squeeze cylinder, and from the anti-product gambi side of the ring-shaped space to the tip of the squeeze plunger. Through the opening of the lubricant passage opening on the outer peripheral wall of the squeeze plunger. A lubrication step of spraying a lubricant, and a cavity forming step of bringing the movable die and the fixed die into contact with each other to form the product cavity and retracting the squeeze plunger in a direction opposite to the product cavity. An injection step of injecting molten metal toward the product cavity side by the injection plunger, a squeeze step of advancing the squeeze plunger toward the product cavity side and pressing the molten metal in the product cavity, the fixed die and the movable die And a take-out step of taking out the product solidified in the product cavity from the product cavity in this order with time. 5. The die casting method according to claim 4, further comprising a vacuum exhaust step of exhausting air in the product cavity during the cavity forming step. 6. A lubricating pin having a lubricant passage therein is projected into a passage connecting the injection plunger and the product cavity during the lubrication step, and the passage is also lubricated through the lubricant passage. The die-casting method according to claim 4 or 5, which has a step of spraying an agent.