JPH08187567A - Die for die casting - Google Patents

Abstract

PURPOSE: To greatly improve the dimensional accuracy of a casting for which a sliding member, such as sliding core, is needed and to prevent the flashing of the casting by detecting the dimensional change of a sliding clearance occurring in the thermal expansion of the sliding member and controlling the sliding member and moving die always at a uniform temp. CONSTITUTION: The sliding part of a core pin 30 is so cooled that the temp. of the sliding part of the core pin 30 is within a range of 0 to -60 deg.C as compared with the temp. of an extrusion sleeve 29 in accordance with the signal sent to a controller from a temp. sensor 36 of the sliding part of the core pin 30 and a temp. sensor 37 of the sliding part of the extrusion sleeve 29. The sliding clearance is then made into 0.05mm if a temp. controller is controlled by the controller. Similarly, the sliding clearance is confined to 0.05mm if the sliding part of the moving die 25 is so heated that the temp. of the sliding part of the moving part 25 is within a range of 0 to +50 deg.C as compared with the temp. of the extrusion sleeve 29 in accordance with the signal sent to the controller from a temp. sensor 38 of the sliding part of the moving die 25 and the temp. sensor 37 of the sliding part of the extrusion sleeve 29.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a die casting mold,
In particular, the present invention relates to a die casting mold in which a part of the surface of the cavity is formed by a sliding member such as a slide core.

[0002]

2. Description of the Related Art In a die-casting die, molten metal is poured into a cavity formed between a fixed die and a movable die for molding. However, depending on the shape of the cast product, a member such as a core is used as the cavity. It must be placed inside.

That is, in the die casting mold shown in FIG. 1, the right side is a fixed part and the left side is a movable part with PL as a boundary.
A cavity 3 is formed between the facing surfaces of the fixed mold 1 and the movable mold 2. Here, the left and right side surfaces of the cavity 3 are formed by the fixed mold 1 and the movable mold 2,
The upper surface is formed by the slide core 4.

The slide core 4 is slidably inserted into a slide groove 2a formed in the vertical direction on the right end surface of the movable die 2 with a proper sliding clearance. The tip end portion of the inclined pin 5 embedded in the fixed mold 1 is inserted into the hole 4a penetrating obliquely upward to the left. When opening the mold after casting is completed, the movable mold 2
Moves to the left, the slide core 4 moves diagonally upward to the left along the tilt pin 5. From a viewpoint of the movable die 2, the slide core 4 slides upward in the sliding groove 2a. That is, the cast product in the cavity 3 is removed vertically upward and released.
6 is a runner, 7 is a plunger, 8 is an extrusion pin,
9 is a return pin.

[0005]

However, in the above-mentioned conventional die casting mold, the slide core 4 has a large heat receiving area (the area forming the cavity 3) in spite of its small size. Since the temperature tends to be higher than that of No. 2, the sliding core 4 may be thermally expanded and cannot slide unless the sliding gap between them is designed to be large in advance.

For this reason, since the sliding gap is set large, the sliding core 4 is loosened, and the dimensional accuracy of the cast product has a certain limit. In addition, especially under conditions where the mold temperature is high and the molten metal is likely to flow, the molten metal may enter the sliding gap and cause burrs on the cast product.
Burrs could remain in the sliding gaps and cause galling.

The present invention has been made in view of the above problems, and it is possible to greatly improve the dimensional accuracy of a cast product requiring a sliding member such as a slide core, and to cause burrs in the cast product. The purpose is to provide a die-casting mold without.

[0008]

In order to achieve the above object, if the sliding member is prevented from being overheated and kept at a temperature equal to that of the movable die, the design value of the sliding gap is set. Can be made smaller than before.

Therefore, the die casting mold of the present invention comprises a fixed mold, a movable mold, and a sliding member slidable with respect to the movable mold, and at least a part of the surface of the cavity is the sliding member. In a die-casting die formed by: a gap detecting means for detecting a sliding gap between the movable die and the sliding member; and a temperature adjusting means for heating or cooling the movable die and / or the sliding member. And a control unit for controlling the temperature adjusting unit according to a detection signal of the gap detecting unit.

In this case, as described in claim 2, in place of the gap detecting means, a temperature detecting means for detecting the temperature of the sliding surface between the movable die and the sliding member may be provided.

Further, as described in claim 3, instead of the gap detecting means, a sliding resistance detecting means for detecting a sliding resistance between the movable die and the sliding member may be provided.

The above structure will be described in detail with reference to the accompanying drawings.

2 and 3 are enlarged views showing the slide core 4 when the second aspect of the present invention is applied to the above-mentioned prior art. In the figure, A is a groove formed in the movable die 2, B is a protrusion of the slide core 4 engaging with the groove, and C is a sliding surface.

Reference numeral 10 is a temperature detecting means such as a thermocouple embedded near the sliding surface C of the movable die 2, and 11 is a temperature detecting means such as a thermocouple embedded near the sliding surface C of the slide core 4. Both are connected to a control device (not shown). Reference numeral 12 is a temperature control path dug inside the slide core 4, and the entire path is arranged in a U-shape.
It is connected to a temperature adjusting device (not shown). The temperature adjusting device circulates oil having a predetermined temperature, and the temperature of the oil is controlled by the control device.

With such a configuration, the control device monitors the temperature detected by the temperature detecting means 10 and 11 and controls the temperature adjusting device so that the temperature difference falls within a certain range. Specifically, the cooling degree of the oil circulating in the temperature control path 12 is adjusted,
The temperature is controlled to be the same as that of the movable mold 2.

As described above, if the temperature difference between the movable die 2 and the slide core 4 during casting is kept uniform, it is not necessary to allow for a sliding gap between the two. Therefore, it may be designed to have a minimum sliding gap that allows the two to smoothly slide at room temperature.

As is clear from the above description, the temperature detecting means directly detects the temperature of the sliding surface between the movable die and the sliding member, the purpose of which is due to the thermal expansion of the sliding member. It is to detect the dimensional change of the sliding gap.

Therefore, as described in claim 1, a dimension measuring device such as a micrometer may be embedded in the movable die to directly measure the sliding gap.

The dimensional change in the sliding gap can be indirectly known by detecting the change in the sliding resistance of the sliding member caused by the change in the sliding gap as described in claim 3. . Specifically, as shown in FIGS. 4 and 5, a ring-shaped pressure sensor 13 is fitted into the root of the projecting portion of the inclined pin 5 embedded in the fixed mold 1, and acts on the inclined pin 5 when the mold is opened. If the component force in the sliding direction is detected,
The sliding resistance of the sliding member can be known.

[0020]

Embodiments of the die-casting mold according to the present invention will be described below with reference to the accompanying drawings. FIG. 6 is an overall front view showing a cross section of the die casting mold.

Reference numeral 21 is a fixed type, which is fixed to a fixed die plate 22 and has inclined pins 23a and 23b embedded therein. The inclined pin 23a moves the slide core 24a upward,
The inclined pins 23b are for moving the slide core 24b downward, respectively.

A movable type 25 is fixed to a movable die plate 28 via a spacer block 26 and a mounting plate 27. The fixed mold 21 and the movable mold 25 are opened by a casting machine with PL as a boundary.

Reference numeral 29 denotes an extrusion sleeve, which is a movable die 25.
The inner diameter is designed to have a sliding gap that allows sliding inside, and the inner diameter is designed to have a sliding gap to the outer diameter of the core pin 30. The left end of the pushing sleeve 29 is fixed to the pushing plate 32.

Reference numeral 31 is an extrusion pin which slidably penetrates through the movable die 25. The left end of the push pin 31 is fixed to the push plate 32, and the right end thereof reaches the runner 34.

Reference numeral 33 is a return pin, which is an extrusion pin 3.
As in the case of 1, the left end is fixed to the push-out plate 32, and the movable mold 2
5 is slidably passed through, the right end is in contact with the PL surface of the fixed die 21, and the push-out plate 32 is pushed back by clamping.

Reference numeral 34 is a runner through which the molten metal passes. Reference numeral 40 denotes a cavity, which is formed by the fixed die 21, the slide core 24, the pushing sleeve 29 as a sliding member, and the core pin 30.

FIG. 7 shows a core pin 30 and an extrusion sleeve 29.
FIG. 6 is an enlarged view showing a movable die 25 and a movable die 25. The core pin 30 has a temperature control path 35 through which a temperature control medium for controlling the mold temperature flows.
Is provided, and the temperature control path 35 communicates with a temperature controller (not shown). A temperature sensor 36 is embedded near the sliding surface E of the core pin 30 with respect to the pushing sleeve 29. Further, the temperature sensor 37 is attached to the pushing sleeve 29.
Is buried.

A temperature sensor 38 is provided in the vicinity of the sliding surface F of the movable die 25 with respect to the sleeve 29, and a temperature adjusting path 39 through which a temperature adjusting medium flows is provided. The temperature control path 39 communicates with a temperature controller (not shown).

The temperature sensors 36, 37, 38 are connected to a control device (not shown), and this control device controls each temperature controller. In this embodiment, the temperature adjusting medium is caused to flow in the temperature adjusting path as the temperature adjusting means, but the temperature of the mold may be adjusted by using a heater such as a cartridge heater.

Next, a method of using the die-casting die of the present embodiment having the above structure will be described.

After the fixed mold 21 and the movable mold 25 are clamped by the casting machine, molten metal is poured into an injection sleeve (not shown) and pushed by a plunger tip to pass through the runner 34, It is filled in the cavity 40. Next, after the molten metal is cooled and solidified, the mold is opened to the left in the figure by the casting machine.

During mold opening, the slide core 24a is moved upward by the inclined pin 23a, and the slide core 24b is moved downward by the inclined pin 23b to separate from the cast product.
Further, the extrusion plate 32 is pushed rightward by the casting machine,
The extrusion sleeve 29 releases the cast product from the core pin 30.

When the mold is clamped by the casting machine after the completion of the mold release, since the return pin 33 projects from the movable mold 25, the return pin 33 abuts against the PL surface of the fixed mold 21 and is pushed back, and the push plate 32 is also the same. Pushed back to. The push-out sleeve 29 and push-out pin 31 are also pushed back in the same manner. Further, during the mold clamping, the tilted pins 23a and 23b are connected to the tilted pin holes 41.
The slide cores 24a and 24b are inserted in the a and 41b and are moved in the center direction.

When the above steps are repeated to continuously perform the casting operation, the core pin 30 and the extrusion sleeve 29 are heated by the heat of the molten metal and thermally expanded. At this time, the core pin 30 has the highest temperature, followed by the extrusion sleeve 29 and the movable die 25 in this order. Therefore, both the sliding gap between the core pin 30 and the pushing sleeve 29 and the sliding gap between the pushing sleeve 29 and the movable die 25 are reduced.

Now, assuming that the outer diameter of the core pin 30 is 50 mm and the outer diameter of the pushing sleeve 29 is 60 mm, the sliding clearance between the core pin 30 and the pushing sleeve 29 (twice G2 in FIG. 8) at room temperature is 0.02 mm. The sliding gap between the pushing sleeve 29 and the movable die 25 (twice the G3 in FIG. 8) is 0.02 mm. Further, the material of each member constituting the mold is SKD61 (alloy tool steel material), and the linear expansion coefficient α = 1.
It is set to 0 × 10 ^-6 / ° C.

Burrs generated during casting are caused by the core pin 30 and the extrusion sleeve 29, and the extrusion sleeve 29 and the movable die 25.
Assuming that the clearance for preventing the damage on the sliding surfaces E and F by entering between the core pin 30 and the sliding surface is 0.05 mm, the temperature of the sliding portion of the core pin 30 is 0 to −60 in comparison with the temperature of the sliding portion of the extrusion sleeve 29. The temperature of the sliding part of the extrusion sleeve 29 is 0 to +5 in comparison with the temperature of the sliding part of the movable die 25 in the range of ° C.
It should be kept in the range of 0 ° C. This is because when calculated from the coefficient of linear expansion, the sliding gap is 0.05 mm when the temperature difference between the core pin 30 and the extrusion sleeve 29 is −60 ° C., and burrs occur if there is a gap larger than that. The pushing sleeve 29 and the movable die 25 are also 0 to + in the same manner.
A range of 50 ° C. is obtained.

Therefore, the temperature sensor 36 at the sliding portion of the core pin 30 and the temperature sensor 3 at the sliding portion of the pushing sleeve 29 are provided.
Based on the signal sent to the controller from 7 and 7, the sliding portion of the core pin 30 is controlled so that the temperature of the sliding portion of the core pin 30 is in the range of 0 to −60 ° C. as compared with the temperature of the extrusion sleeve 29. If the temperature controller is controlled by the control device so as to cool, the sliding gap falls within the above range.

Similarly, based on the signals sent from the temperature sensor 38 of the sliding part of the movable die 25 and the temperature sensor 37 of the sliding part of the extrusion sleeve 29 to the control device, the sliding part of the movable part 25. Temperature is 0 to +50 compared to the temperature of the extrusion sleeve 29.
If the temperature controller is controlled by the control device so as to heat the sliding portion of the movable portion 25 so that it is in the range of ° C, the sliding clearance falls within the above range.

[0039]

As described above, according to the die casting mold of the present invention, the dimensional change of the sliding gap due to the thermal expansion of the sliding member is detected, and the sliding member and the movable mold are always kept at a uniform temperature. The sliding clearance can be designed to be small, and as a result, the dimensional accuracy of castings that require sliding members such as slide cores can be greatly improved. Also, there will be no burrs on the cast product.

[Brief description of drawings]

FIG. 1 is an overall front view showing a cross section of a conventional die casting mold to which the present invention is applied.

FIG. 2 is an enlarged front view showing a slide core when claim 2 of the present invention is applied to the die casting mold of FIG.

FIG. 3 is a top view of FIG.

FIG. 4 is an enlarged front view showing a slide core when the third aspect of the present invention is applied to the die casting mold of FIG. 1.

5 is a top view of FIG. 4. FIG.

FIG. 6 is an overall front view showing a cross section of a die casting mold according to an embodiment of the present invention.

7 is an enlarged view of a main part of the die casting mold of FIG.

8 is an enlarged view of a main part of the die casting mold of FIG.

[Explanation of symbols]

 1 Fixed type 2 Movable type 2a Sliding groove 3 Cavity 4 Sliding core 4a Hole 5 Tilt pin 6 Runner 7 Plunger 8 Extrusion pin 9 Return pin 10 Temperature detection means 11 Temperature detection means 12 Temperature control path 13 Pressure sensor

Claims (3)

[Claims] 1. A die casting metal comprising a fixed die, a movable die, and a sliding member slidable with respect to the movable die, wherein at least a part of the surface of the cavity is formed by the sliding member. In the mold, a gap detecting means for detecting a sliding gap between the movable die and the sliding member, a temperature adjusting means for heating or cooling the movable die and / or the sliding member, and a detection by the gap detecting means. A die-casting die, comprising: a control unit that controls the temperature adjusting unit according to a signal. 2. The die casting mold according to claim 1, further comprising temperature detecting means for detecting a temperature of a sliding surface between the movable die and the sliding member, instead of the gap detecting means. . 3. The die casting mold according to claim 1, further comprising a sliding resistance detecting means for detecting a sliding resistance between the movable die and the sliding member, instead of the gap detecting means. .