JP2007283371A - Spool bush of die casting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an improved spool bush for die casting machine with which in the case of opening the dies, a product biscuit is pushed out by smoothly advancing a plunger tip in the spool bush. <P>SOLUTION: Since this spool bush 1 arranges non-contacting part 12 which does not contact with the outer peripheral surface of a plunger tip 7 at the rear side from the front end surface 7a of the plunger tip 7 in the case of filling up and solidifying the molten metal, and on the inner peripheral surface from a prescribed position 18 at the front side of the rear end surface 7b of the plunger tip 7 to the front end part 1a of the spool bush 1 in the case of opening the dies; when the dies are opened, the peripheral edge part of the front end part 7a of the plunger tip 7 is not encroached upon the inner peripheral surface of the spool bush 1, and this sliding resistance can be made to small, and the plunger tip 7 can smoothly be advanced in the spool bush 1 and the product biscuit can be pushed out. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a spool bush of a die casting machine in which a plunger tip slides, and more specifically, a peripheral portion of a front end surface that presses a molten metal of a plunger tip when the mold is opened is an inner periphery of the spool bush. The present invention relates to a spool bush improved so as to smoothly advance and extrude a product biscuit without biting into the surface.

  In general, in a die-casting machine, as shown in FIG. 1, a cylindrical spool bush 51 (see FIG. 6) for supplying molten metal into the cavity 4 is fitted into the fixed mold 2. A cylindrical plunger sleeve 5 is connected to the rear end of the spool bush 51, and a pouring port 6 for supplying molten metal is provided on the peripheral wall portion of the rear portion of the plunger sleeve 5. . A cylindrical plunger tip 7 is slidably provided from the plunger sleeve 5 to the spool bush 51.

Then, as shown in FIGS. 1 and 6 (a), after the fixed mold 2 and the movable mold 3 are clamped, the molten metal (spotted portion in FIG. 6 (a)) is introduced from the pouring port 6 of the plunger sleeve 5. Is poured. Subsequently, the plunger tip 7 advances from the position shown in FIG. 6A, and the molten metal is guided from the plunger sleeve 5 to the spool bush 51 by the front end surface 7a. The cavity 4 formed between the two fixed inserts 2b and the movable insert 3b of the movable mold 3 is filled. After filling, the plunger tip 7 advances further at a low speed until the molten metal solidifies in the cavity 4, applies pressure to the molten metal in the cavity 4, and stops at the position shown in FIG. 6 (b). .
Thereafter, as shown in FIGS. 1 and 6C, when the molten metal in the cavity 4 is solidified and the movable mold 3 is detached from the fixed mold 2 and opened, the cast molded product 15 (FIG. 1 in the cavity 4) is detached from the fixed mold 2 while sticking to the movable insert 3b of the movable mold 3, and the plunger tip 7 is also advanced from the position of FIG. The product biscuits 15 a (the molten metal solidified between the plunger tip 7 and the spool core 3 c in FIG. 6C) is released so as to be pushed out from the spool bush 51.
As shown in FIG. 6, the conventional spool bush 51 is provided with a tapered portion 53 between its inner peripheral surface and its front end portion 51a, and the molten metal flows into the cavity 4 during filling. In addition, the product biscuit 15a can be easily detached from the spool bush 51 when the mold is opened.

  However, in the above-described casting process, as shown in FIG. 7A, when mold clamping is performed in a state in which a foreign object 52 such as a burr is attached below the front end portion 51a of the spool bush 51, FIG. ), When the spool core 3c collides with the foreign object 52, the lower portion of the peripheral wall portion on the spool core 3c side of the spool bush 51 is pushed upward, and the portion on the spool core 3c side of the spool bush 51 is shown in FIG. 8 is in a state of being deformed into a horizontally long elliptical cylinder as indicated by a solid line.

In this way, when the mold is opened with the portion on the spool core 3c side of the spool bush 51 deformed into an elliptical cylinder shape, the plunger tip 7 moves from the position shown in FIG. 6B to the position shown in FIG. 6C. When the product biscuits 15a are pushed forward and moved forward, the peripheral edge portion of the front end surface 7a of the plunger tip 7 slides so as to bite into the inner peripheral surface of the spool bush 51, so that the sliding resistance increases.
Therefore, the front end surface 7a of the plunger tip 7 cannot smoothly push out the product biscuit 15a, and the plunger tip 7 becomes unable to follow the movement of the product biscuit 15a, so that the cast molded product 15 in the cavity 4 (FIG. 1). And the product biscuit 15a, and the spool bush 51 is replaced at this time.

Further, as a prior art of a spool bush of a die casting machine, Patent Document 1 discloses that a spool bush is formed by fitting an insert liner to an inner peripheral surface of the bush body, and the bush body and the insert liner are fitted. Cooling grooves that allow cooling fluid to flow are provided on the outer peripheral surface of the insert runner, which is the surface, and the spool bushing is sufficiently cooled by the cooling water, and cracks due to thermal stress accompanying the temperature rise when the molten metal passes through It is disclosed that it is difficult to occur.
JP 2003-10953 A

  However, the invention of Patent Document 1 is provided with a cooling groove in the spool bushing, which makes it difficult for cracks due to thermal stress accompanying the temperature rise when the molten metal passes through. When the plunger tip moves forward while pushing out the product biscuits in the spool bush, the peripheral edge of the front end surface of the plunger tip slides into the inner peripheral surface of the spool bush, so the sliding resistance increases. As a result, the problem that the plunger tip cannot be pushed forward and the product biscuit cannot be pushed out cannot be solved.

  The present invention has been made in view of the above points, and provides a spool bush of a die casting casting machine that is improved so that a plunger tip can smoothly advance in the spool bush and push out a product biscuit when the mold is opened. The purpose is to do.

According to the present invention, as a means for solving the above-mentioned problems, the invention of the spool bush of the die-casting machine according to claim 1 is a spool bush provided in the die-casting machine, in which the plunger tip slides. The spool bush is a predetermined rear side of the front end surface of the plunger tip during filling and solidification of the molten metal into the cavity and a front side of the rear end surface of the plunger tip during mold opening. A non-contact portion that does not contact the outer peripheral surface of the front end portion of the plunger tip is provided on the inner peripheral surface from the position to the front end portion of the spool bush.
The invention of the spool bush of the die-casting machine described in claim 2 is the invention described in claim 1, wherein the non-contact portion is formed on the inner peripheral surface of the spool bush from the position in front of the predetermined position. A tapered portion that gradually expands toward the front end portion of the spool bush is formed, and extends from the predetermined position toward the front end portion of the spool bush with substantially the same diameter that is larger than the outer peripheral surface of the plunger tip. It is characterized by forming a large-diameter recessed portion.
The invention of the spool bush of the die-casting machine according to claim 3 is the invention according to claim 1, wherein the non-contact portion is formed on the inner peripheral surface of the spool bush from the predetermined position to the front end portion of the spool bush. It is characterized in that it is formed by forming a tapered portion that gradually expands toward.

Therefore, in the invention of the spool bush of the die casting machine according to the first aspect, when the plunger tip moves forward while pushing out the product biscuit in the spool bush when the mold is opened, the part on the spool core side of the spool bush is temporarily Even in the state of being deformed into a horizontally long elliptical cylinder, the peripheral edge of the front end surface of the plunger tip does not bite into the inner peripheral surface of the spool bush, and its sliding resistance is small, so the plunger tip is smooth. Proceed to push out the product biscuits.
In the invention of the spool bush of the die casting machine according to claims 2 and 3, the periphery of the front end surface of the plunger tip does not bite into the inner peripheral surface of the spool bush when the mold is opened, and the plunger tip is smooth. The product biscuits are pushed forward to push the product biscuits, and the inner peripheral surface on the front end side of the spool bush is formed in a tapered shape that gradually expands toward the front end, so that the molten metal enters the cavity during filling. In addition to being easy to flow, the product biscuits are easily detached from the spool bush when the mold is opened.

  ADVANTAGE OF THE INVENTION According to this invention, the spool bush of the die-casting machine improved so that a plunger chip can advance smoothly in a spool bush and can extrude a product biscuit can be provided at the time of a mold opening.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS. In addition, the same member as a prior art example is demonstrated using the same code | symbol.
In general, as shown in FIG. 1, the main part of the die casting machine has a fixed mold 2 and a movable mold that moves in a substantially horizontal direction with respect to the fixed mold 2 to clamp and open the mold. 3 is provided. The fixed mold 2 is configured by holding a fixed insert 2b on a fixed main mold 2a. On the other hand, the movable mold 3 is also configured by holding a movable nest 3b on a movable main mold 3a. The movable nest 3b is synchronized with the movable nest 3b at a portion facing a plunger chip 7 described later. A movable spool core 3c is continuously provided. At the time of clamping, a cavity 4 is formed between the fixed insert 2b and the movable insert 3b.

A cylindrical spool bush 1 communicating with the cavity 4 is fitted into the fixed main mold 2 a of the fixed mold 2 so as to supply molten metal into the cavity 4. A cylindrical plunger sleeve 5 having the same inner diameter is connected to the rear end portion of the spool bush 1. A pouring port 6 for pouring the molten metal is formed in the peripheral wall portion at the rear of the plunger sleeve 5.
Further, a cylindrical plunger tip 7 is slidably provided in the spool bush 1 and the plunger sleeve 5. A plunger rod 8 is connected to the rear end surface 7 b of the plunger tip 7. An injection cylinder (not shown) is connected to the plunger rod 8, and the plunger tip 7 slides back and forth in the spool bush 1 and the plunger sleeve 5 by driving the injection cylinder.

  As shown in FIG. 2, the spool bush 1 of the die casting machine according to the embodiment of the present invention has a plunger tip at the time of filling and solidifying the molten metal into the cavity 4 (state shown in FIG. 2A). 7 to the front end portion 1a of the spool bush 1 from a predetermined position 18 on the rear side of the front end surface 7a and on the front side of the rear end surface 7b of the plunger tip 7 when the mold is opened (the state shown in FIG. 2B). The non-contact part 12 which does not contact the outer peripheral surface of the front end part of the plunger tip 7 is provided on the inner peripheral surface.

The non-contact portions 12, 12a, 12b of the spool bush 1 are configured in any of three forms described below.
First, the non-contact part 12 which concerns on 1st Embodiment is comprised as follows.
That is, as shown in FIGS. 2 and 3, the non-contact portion 12 is formed on the inner peripheral surface of the spool bush 1 from the position slightly ahead of the predetermined position 18 that is the starting point of the non-contact portion 12. A tapered portion 13 that gradually expands toward the portion 1a is formed. Further, a large-diameter recessed portion 14 that extends from the predetermined position 18 toward the front end portion 1a of the spool bush 1 with a substantially same diameter larger than the outer diameter of the plunger tip 7 is formed at the starting portion of the tapered portion 13. Formed and configured.

  Next, as shown in FIG. 4, the non-contact portion 12 a according to the second embodiment is disposed on the inner peripheral surface of the spool bush 1 from the predetermined position 18 that is the starting point of the non-contact portion 12 a. A tapered portion 13 is formed that gradually expands toward 1a.

Next, as shown in FIG. 5, the non-contact portion 12 b according to the third embodiment is formed on the inner peripheral surface of the spool bush 1 from the predetermined position 18 that is the starting point of the non-contact portion 12 b. In the range up to 1a, a large-diameter recessed portion 20 extending substantially the same diameter as the outer diameter of the plunger tip 7 is formed, and the large-diameter recessed portion 20 and the front end of the spool bush 1 are formed. The taper part 21 is provided between 1a.
The non-contact portion 12b according to the third embodiment is different from the non-contact portion 12 according to the first embodiment in the length of the large-diameter recessed portion 20 and the taper portion 21. The angle is the difference.

The operation of the die casting machine using the spool bush 1 will be described.
First, after the movable mold 3 is moved to the fixed mold 2 side and the mold is clamped, the molten metal is poured from the pouring port 6 of the plunger sleeve 5. Subsequently, the plunger tip 7 moves forward, and the molten metal is guided from the plunger sleeve 5 to the spool bush 1 by the front end surface 7 a and filled into the cavity 4. After filling, the plunger tip 7 advances further at a low speed until the molten metal solidifies in the cavity 4, applies pressure to the molten metal in the cavity 4, and stops at the position shown in FIG. .

Thereafter, at the time of mold opening, the movable nest 3b and the spool core 3c move so as to be detached from the fixed nest 2b and the spool bush 1, and at the same time, the plunger tip 7 advances from the position of FIG. Then, the cast molded product 15 is detached from the fixed insert 2b while sticking to the movable insert 3b, and the plunger tip 7 moves forward smoothly so as to push out the product biscuit 15a attached in the spool bush 1. Then, the product biscuit 15a is detached from the spool bush 1 and stopped at the position shown in FIG.
When the plunger tip 7 moves forward from the filling / solidification position shown in FIG. 2A to the position shown in FIG. 2B when the mold is opened, the front end surface 7a of the plunger tip 7 is opened. Since the peripheral edge portion does not bite into the inner peripheral surface (non-contact portion 12, 12a, 12b) of the spool bush 1, the sliding resistance is reduced, and the plunger tip 7 can smoothly advance in the spool bush 1. The product biscuit 15a can be extruded.

As described above, the spool bush 1 of the die casting machine according to the embodiment of the present invention has a plunger tip on the inner peripheral surface from the predetermined position 18 in the length direction to the front end portion 1a of the spool bush 1. 7 is provided with non-contact portions 12, 12a, 12b that do not come into contact with the outer peripheral surface of the front end portion, even if the portion on the spool core 3c side of the spool bush 1 is deformed into a horizontally long elliptical cylinder. When the mold is opened, the peripheral edge of the front end surface 7a of the plunger chip 7 when the plunger chip 7 moves forward from the filling / solidification position of FIG. 2 (a) to the mold opening position of FIG. 2 (b). The part does not bite into the inner peripheral surface (non-contact part 12, 12a, 12b) of the spool bush 1 and its sliding resistance can be reduced, and the plunger tip 7 is smoothly advanced in the spool bush 1 and manufactured. It is possible to push out the biscuits 15a.
Moreover, even when the plunger tip 7 is retracted from the position when the mold is opened in FIG. 2B, the outer peripheral surface of the plunger tip 7 is the inner peripheral surface (non-contact portion) of the spool bush 1 on the spool core 3c side. 12, 12a, 12b), so that it can be moved backward smoothly.

FIG. 1 is a diagram showing a main part of a die casting machine employing a spool bush according to an embodiment of the present invention. FIG. 2 shows a non-contact portion according to the first embodiment of the spool bush, wherein (a) shows the position of the plunger tip in the spool bush when filling and solidifying, and (b) when the mold is opened. FIG. FIG. 3 is an enlarged view of a portion A in FIG. FIG. 4 is a view showing a non-contact portion according to the second embodiment of the spool bush. FIG. 5 is a view showing a non-contact portion according to the third embodiment of the spool bush. FIG. 6 is a diagram showing stepwise movement of the plunger tip during die casting. FIG. 7 is a diagram showing a process when the spool core side of the spool bush is deformed. FIG. 8 is a view showing a deformed shape of the spool bush on the spool core side.

Explanation of symbols

1 Spool bush, 1a Front end, 2 Fixed mold, 3 Movable mold, 4 Cavity, 7 Plunger tip, 7a Front end face, 7b Rear end face, 12, 12a, 12b Non-contact part, 13 Taper part, 14 Large diameter Recessed part, 15 Cast molding, 15a Product biscuit, 18 Predetermined position, 20 Large diameter recessed part, 21 Tapered part

Claims (3)

A spool bush provided in a die casting machine, in which a plunger tip slides,
The spool bush is located at a position behind the front end surface of the plunger tip when filling and solidifying the molten metal into the cavity and from a predetermined position before the rear end surface of the plunger tip when opening the mold. A spool bush for a die-casting machine, wherein a non-contact portion that does not contact the outer peripheral surface of the front end portion of the plunger tip is provided on the inner peripheral surface up to the front end portion of the spool bush.   The non-contact portion forms, on the inner peripheral surface of the spool bush, a tapered portion that gradually expands from a position in front of the predetermined position toward the front end of the spool bush, and from the predetermined position to the spool. 2. The die-casting according to claim 1, wherein a large-diameter recessed portion extending substantially in the same diameter as the outer peripheral surface of the plunger tip is formed toward the front end portion of the bush. The spool bush of the machine. The non-contact portion is configured by forming a tapered portion that gradually expands from the predetermined position toward the front end portion of the spool bush on the inner peripheral surface of the spool bush. Spool bushing of the described die casting machine.

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