JP2007007669A - Die casting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a die casting device where wear of a plunger tip and a sleeve can be suppressed. <P>SOLUTION: The die casting device is provided with a die, a sleeve, a plunger tip 40, and a plunger rod 31. The die has a cavity, and a gate making the cavity communicate with the outside. The sleeve is fixed to the die, and communicates with the cavity via the gate. The plunger tip 40 is arranged in the sleeve so as to be freely slidable. In the plunger rod 31, the plunger tip 40 is mounted on the tip in a rockable state around a rocking center 50, and it makes the plunger tip 40 progress toward the die. Then, the center of gravity of the plunger tip 40 is located more on the side opposite to that of the die than the rocking center 50 in the plunger tip. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a die casting apparatus.

A die casting apparatus including a mold, an injection machine, and a sleeve is known. The mold has a cavity formed inside and a gate for communicating the cavity with the outside. The injection machine has a cylinder, a plunger rod, and a plunger tip. The cylinder extends the plunger rod toward the mold. The sleeve is fixed to the mold and communicates with the cavity via the gate, and guides the plunger tip in a slidable manner. When the plunger rod extends, the plunger tip advances toward the mold. As the plunger tip moves forward, the molten metal contained in the sleeve passes through the gate and fills the cavity of the mold.
Patent Document 1 discloses a technique for attaching a plunger tip to the tip of a plunger rod with a gap provided. According to this configuration, even if the axis of the sleeve and the axis of the plunger rod are misaligned, the plunger tip that moves forward is prevented from squeezing the inner surface of the sleeve, and wear of the plunger tip and the sleeve can be suppressed. Are listed.

Japanese Patent Laid-Open No. 6-142876

In the technique disclosed in Patent Document 1, the rear end surface of the plunger tip is formed in a shape along a spherical surface centered on the center of gravity. The front end surface of the plunger rod is formed in a concave spherical shape, and the rear end surface of the plunger tip enters therein. Therefore, the plunger tip can swing around the center of gravity. When filling the mold cavity with the molten metal, the front end surface of the plunger rod presses the rear end surface of the plunger tip. When the front end surface of the plunger rod presses the rear end surface of the plunger tip, the plunger tip advances.
As the plunger tip moves forward, an inertial force acts on its center of gravity. The center of gravity and the center of oscillation of the plunger tip do not always coincide completely due to factors such as manufacturing variations. When the center of gravity of the plunger tip is located on the opposite side of the cylinder from the center of oscillation, a moment is generated to tilt the plunger tip shaft with respect to the sleeve shaft due to the inertial force acting on the center of gravity of the plunger tip. To do. Therefore, the corner portion of the plunger tip is pressed against the inner surface of the sleeve. When the corners of the plunger tip are pressed against the inner surface of the sleeve, the plunger tip rubs against the inner surface of the sleeve, causing them to wear quickly.
The present invention has been made to solve the problem, and realizes a die casting apparatus capable of suppressing wear of a plunger tip and a sleeve.

The die casting apparatus of the present invention includes a mold, a sleeve, a plunger tip, and a plunger rod. The mold has a cavity and a gate for communicating the cavity with the outside. The sleeve is fixed to the mold and communicates with the cavity via the gate. The plunger tip is slidably disposed in the sleeve. The plunger rod is attached to the tip so that the plunger tip can swing around the swing center, and advances the plunger tip toward the mold. The center of gravity of the plunger tip is located on the side opposite to the mold from the swing center of the plunger tip.
In this die casting apparatus, the center of gravity of the plunger tip is located on the side opposite to the mold from the swing center. For this reason, when the plunger tip moves forward, an inertial force acting on its center of gravity generates a moment for turning the plunger tip so that the plunger tip axis and the sleeve axis become more parallel. That is, the plunger tip axis and the sleeve axis can be made more parallel by positively positioning the center of gravity of the plunger tip on the side opposite to the mold than the center of oscillation. For this reason, the corner portion of the plunger tip is not pressed against the inner surface of the sleeve, and the plunger tip is prevented from being twisted on the inner surface of the sleeve. Therefore, wear of the plunger tip and the sleeve can be suppressed.

  According to the present invention, it is possible to suppress the wear of the plunger tip and the sleeve by positioning the center of gravity of the plunger tip closer to the die side than the swing center of the plunger tip.

The preferred embodiment of this invention is illustrated.
(Form 1)
Mold,
A sleeve fixed to the mold;
A plunger tip disposed within the sleeve;
It has a cylinder that extends the plunger rod toward the mold,
The mold has a cavity formed inside and a gate for communicating the cavity with the outside.
The sleeve slidably guides the plunger tip and communicates with the cavity via the gate.
The plunger tip has a recess extending along the axis from the cylinder side to the gate side,
The tip of the plunger rod has entered the recess,
The plunger tip and the plunger rod are arranged in a position on the gate side rather than a position where the end on the gate side and the end on the cylinder side of the sliding surface of the plunger tip that slides on the inner surface of the sleeve are halved in the sliding direction. A die-casting device which is in contact with
(Form 2)
2. The die casting apparatus according to claim 1, wherein the plunger tip and the plunger rod are in contact with each other so as to be swingable.

An embodiment according to the die casting apparatus of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the die casting apparatus 10 includes a base 11, a mold 12, a sleeve 37, an injection machine 14, and a pair of tie rods 52.
The mold 12 is disposed on the base 11. As shown in FIGS. 2 and 3, the mold 12 includes a fixed platen 20, a fixed mold 21, a movable mold 23, a movable platen 22, and four tie bars 24. The fixed platen 20 is fixed to the base 11. The fixed mold 21 is attached to the fixed platen 20. The movable mold 23 is attached to the movable platen 22. The movable platen 22 is supported by an opening / closing mechanism (not shown), and can move on the base 11 in the horizontal direction. The tie bar 24 connects the fixed platen 20 and the movable platen, and guides the horizontal movement of the movable platen 22. The movable platen 22 is driven by an opening / closing mechanism and moves between a mold clamping position approaching the fixed platen 20 and a mold opening position separated from the fixed platen 20. 2 and 3 show a state in which the movable platen 22 is disposed at the mold clamping position.
When the movable platen 22 is arranged at the mold clamping position, the fixed mold 21 and the movable mold 23 form a cavity 25 for casting product molding. When the movable platen 22 is disposed at the mold opening position, the fixed mold 21 and the movable mold 23 are opened (separated), and the cast product molded in the cavity 25 can be taken out.
The sleeve 37 is formed in a cylindrical shape and penetrates the fixed platen 20. The inside of the sleeve 30 and the cavity 25 communicate with each other via a gate 26 provided in the fixed mold 21.

The injection machine 14 includes a base member 32, a support member 33, an injection cylinder 30, and a plunger tip 40.
The base member 32 is fixed to the base 11. As shown in FIG. 4, the lower end portion 34 of the support member 33 is mounted on the base member 32 in a state where the lower end portion 34 is movable in the horizontal direction and the movement in the vertical direction is restricted.
As shown in FIGS. 2 and 3, the injection cylinder 30 has a cylinder body 35, a plunger rod 31, and a cylinder plate 38. The cylinder body 35 is fixed to the support member 33 and incorporates a piston (not shown). The plunger rod 31 is fixed to the piston. The cylinder plate 38 is fixed to the end of the cylinder body 35 on the mold 12 side. The cylinder body 35 is supplied with hydraulic pressure, and the piston moves within the cylinder body 35 by switching between applying the hydraulic pressure to one side or the other side of the piston. As the piston moves, the plunger rod 31 expands and contracts. 2 and 3 show the plunger rod 31 in a contracted state. The plunger tip 40 is inserted into the sleeve 37 in a state of being attached to the distal end portion 41 of the plunger rod 31.

As shown in FIG. 5, the distal end portion 41 of the plunger rod 31 is formed in a substantially spherical shape. The tip portion 41 and the rod main body 42 are formed with a through hole 48 penetrating them. The plunger tip 40 is formed with a substantially hemispherical recess 43. The distal end portion 41 of the plunger rod 31 enters the recess 43. A ring-shaped member 44 is fixed in the plunger tip 40 by a plurality of bolts 45. A portion 46 that is a part of the inner peripheral surface of the ring-shaped member 44 is in sliding contact with the tip portion 41. The plunger tip 40 can swing around the swing center 50 in a state where the plunger tip 40 is attached to the distal end portion 41 of the plunger rod 31 (can swing the neck).
The plunger tip 40 is formed with a cooling hole 64 communicating with the through hole 48 of the plunger rod 31. A cooling forward pipe and a cooling return pipe (not shown) pass through the through hole 48 and the cooling hole 64. The coolant fed from the cooling source to the plunger tip 40 via the cooling forward piping flows through a cooling passage (not shown) to cool the plunger tip 40 and then to the cooling source via the cooling return piping. Return.

As shown in FIG. 5, the center of gravity 63 of the plunger tip 40 is located closer to the injection cylinder 30 than the swing center 50.
As shown in FIGS. 1 and 3, the tie rod 52 connects the fixed platen 20 and the cylinder plate 38 of the injection cylinder 30. The axis of the tie rod 52 extends in the same direction as the axis of the sleeve 37 and is disposed at a symmetrical position with respect to the axis of the sleeve 37.

  As shown in FIGS. 2 and 3, when a cast product is formed by the die casting apparatus 10, the molten metal 54 is supplied into the sleeve 37 via a supply runner (not shown). After supplying the molten metal 54 into the sleeve 37, the plunger rod 31 of the injection cylinder 30 is rapidly extended. When the plunger rod 31 extends, the plunger tip 40 moves forward to the stationary mold 21 side. The plunger tip 40 that moves forward fills the cavity 25 with the molten metal 54 via the gate 26 of the fixed mold 21. 6 and 7 illustrate a state in which the cavity 25 is filled with the molten metal 54. The molten metal 54 filled in the cavity 25 is cooled by the coolant passing through the cooling flow paths (not shown) of the molds 21 and 23. The cooled molten metal 54 is solidified. After the molten metal 54 has solidified, the movable platen 22 is moved to the mold opening position, and the cast product is taken out from the die casting apparatus 10.

When filling the cavity 25 with the molten metal 54, the plunger tip 40 moves forward together with the plunger rod 31, and strongly pushes the molten metal 54 into the narrow gate 26. Therefore, a large reaction force (for example, 800 tons) that separates the mold 12 and the injection cylinder 30 acts (hereinafter, the reaction force is referred to as “injection reaction force”). When the injection reaction force acts, the tie rod 52 extends. When the tie rod extends, the support member 33 slides with respect to the base member 32, and at the same time, the injection cylinder 30 moves in a direction away from the mold 12. When the filling of the molten metal 54 into the cavity 25 is completed, the injection reaction force does not act and the tie rod 52 contracts, whereby the injection cylinder 30 returns to its original position.
On the other hand, when the injection machine 14 is fixed to the base 11, the cylinder plate 38, the cylinder body 35, the support member 33, and the base 11 are greatly deformed by the injection reaction force. The fixed platen 20 is also deformed by an injection reaction force acting on itself, but is deformed greatly and complicatedly by the influence of the deformation of the cylinder plate 38, the cylinder body 35, the support member 33, and the base 11. When the fixed platen 20 is deformed, the molds 21 and 23 are also deformed. When the molds 21 and 23 are deformed, the cast product may not be formed into a desired shape, or a gap may be formed between the molds 21 and 23. When a gap is formed between the molds 21 and 22, the molten metal 54 leaks to the outside.
However, if the rigidity of each part is increased so that the deformation due to the injection reaction force is reduced, the die casting machine becomes enormous.

In the die casting apparatus 10 of the present embodiment, the injection cylinder 30 moves as the tie rod 52 extends due to the injection reaction force. As already described, the axis of the tie rod 52 extends in the same direction as the axis of the sleeve 37 and is disposed at a symmetrical position with respect to the axis of the sleeve 37. For this reason, only the force symmetrical to the axis of the sleeve 37 acts on the fixed platen 20 in the axial direction of the tie rod 52. Since only a force symmetric with respect to the axis of the sleeve 37 acts, the fixed platen does not deform greatly and complicatedly. That is, the deformation of the fixed platen 20 is suppressed. When the deformation of the fixed platen 20 is suppressed, the deformation of the molds 21 and 22 is also suppressed. Therefore, the product accuracy of the cast product is improved and the molten metal 54 is prevented from leaking outside the molds 21 and 23.
Three or more tie rods 52 can be provided. In that case, the tie rods 52 are arranged at substantially equal intervals around the axis of the sleeve 37. With this configuration, a resultant force of the forces acting in the axial direction of each tie rod 52, that is, a force equal to the injection reaction force acts on the fixed platen 20 around the axis of the sleeve 37. For this reason, deformation of the stationary platen 20 can be suppressed.

  As already described, in the die casting apparatus 10 of the present embodiment, the center of gravity 63 of the plunger tip 40 is located on the injection cylinder 30 side with respect to the swing center 50 of the plunger tip 40. For this reason, when the plunger rod 31 extends, a moment for making the axis of the plunger tip 40 and the axis of the sleeve 37 more parallel acts on the plunger tip 40. That is, by positioning the center of gravity 63 of the plunger tip 40 closer to the injection cylinder 30 than the swing center 50 of the plunger tip 40, the axis of the plunger tip 40 and the axis of the sleeve 37 are actively brought close to parallel. For this reason, the inner surface 57 of the sleeve 37 and the side surface 58 of the plunger tip 40 slide in a state where the surfaces are stable. For this reason, the wear of the sleeve 37 and the plunger tip 40 is suppressed, and their life is prolonged. Further, since the plunger tip 40 is prevented from being squeezed on the inner surface of the sleeve 37, it is allowed that the thrust for moving the plunger tip 40 forward is small, and the injection reaction force is also reduced.

  On the other hand, as shown in FIG. 8, when the center of gravity 63 of the plunger tip 40 is located on the reflection cylinder 30 side of the swing center 50 of the plunger tip 40, the plunger rod 31 extends and the plunger When the tip 40 moves forward, a moment is applied to rotate the plunger tip 40 so that the axis of the plunger tip 40 is inclined with respect to the axis of the sleeve 37. Therefore, as shown in part A, the corners of the plunger tip 40 are pressed against the inner surface 57 of the sleeve 37, and the plunger tip 40 squeezes the sleeve inner surface 57. For this reason, the plunger tip 40 and the sleeve 37 are worn, and their lifetime is shortened. Further, if the plunger tip 40 squeezes the inner surface 57 of the sleeve 37, the injection reaction force also increases.

  Even if the center of gravity of the plunger tip 40 is made to coincide with the center of gravity, it is actually difficult to make the center of oscillation coincide with the center of gravity due to manufacturing errors or thermal deformation of the plunger tip 40, the plunger rod 31, etc. . If the center of gravity of the plunger tip 40 does not coincide with the center of gravity, and the center of gravity 63 of the plunger tip 40 is positioned on the reflecting cylinder 30 side of the center of swing 50, when the plunger tip 40 moves forward, FIG. The same event occurs as shown in.

  The swing center of the plunger tip 40 can be positioned closer to the gate than the position that divides the axial length into two. If comprised in this way, when the plunger tip 40 advances, the axis | shaft of the plunger tip 40 and the axis | shaft of the sleeve 37 will be arrange | positioned more in parallel. Therefore, wear of the plunger tip 40 and the sleeve 37 is suppressed.

  Even if the plunger tip 40 is mounted so as not to swing with respect to the plunger rod 31, the center of gravity 63 of the plunger tip 40 is positioned closer to the reflecting cylinder 30 than the swing center 50 of the plunger tip 40, or the plunger tip It is effective to suppress the wear of the plunger tip 40 and the sleeve 37 by positioning the swing center of 40 on the gate side from the position that divides the axial length into two. This is because the plunger tip 40 and the sleeve 37 are arranged more in parallel by the deformation of the plunger tip 40 and the plunger rod 31.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

The typical perspective view of a die-casting apparatus. The longitudinal cross-sectional view of a die-cast apparatus. The horizontal fragmentary sectional view of a die-casting apparatus. Sectional drawing of a base, a base member, and a supporting member. Sectional drawing of the state in which the plunger tip was mounted | worn with the plunger rod. The longitudinal cross-sectional view of a die-cast apparatus. The horizontal fragmentary sectional view of a die-casting apparatus. A typical sectional view of a sleeve, a plunger tip, and a plunger rod.

Explanation of symbols

10: Die casting apparatus 11: Base 12: Mold 14: Injection machine 20: Fixed platen 21: Fixed mold 22: Movable platen 23: Movable mold 24: Tie bar 25: Cavity 26: Gate 30: Injection cylinder 31: Plunger Rod 32: Base member 33: Support member 34: Lower end 35: Cylinder body 37: Sleeve 38: Cylinder plate 40: Plunger tip 42: Rod body 43: Recess 44: Ring-shaped member 46: Part 48: Through hole 50: Shaking Moving center 52: Tie rod 54: Molten metal 63: Center of gravity 64: Cooling hole

Claims (1)

A mold having a cavity and a gate for communicating the cavity with the outside;
A sleeve fixed to the mold and communicating with the cavity via the gate;
A plunger tip slidably disposed within the sleeve;
The plunger tip is attached to the tip in a state that it can swing around the swing center, and has a plunger rod that advances the plunger tip toward the mold,
A die casting apparatus characterized in that the center of gravity of the plunger tip is located on the side opposite to the mold from the swing center of the plunger tip.

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