JP3295367B2 - Positioning device for sliding core - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for a sliding core of a die-casting die, for example.

[0002]

2. Description of the Related Art Conventionally, as a mold for die-casting a molded article having an undercut portion, a mold using a sliding core that moves forward and backward in conjunction with opening and closing of a movable mold has been known. As a mechanism for guiding such sliding of the sliding core and for positioning the sliding core in the mold clamping state, for example, a plan view of the sliding core shown in FIG. A state in which the core has moved in the mold clamping direction) and a structure as shown in FIG. 4, which is a cross-sectional view taken along line BB of FIG. 3, are known.

The mechanism for preventing displacement is provided with a pair of side key guides 53 for guiding the sliding core 52 to slide on the upper surface of the lower die 51. Is provided with a core pin 54 as an undercut molded portion so as to be able to protrude and retract into the cavity, and a rod 55 extending along the sliding direction is connected to the rear surface side. A spring 56 is engaged with the rod 55, and the sliding core 52 is urged in the backward direction by the urging force of the spring 56. The sliding core 52
Is provided with a pin fitting hole 57 which penetrates in a slanting manner in the up and down direction. When an inclined pin provided on a movable die (not shown) is fitted into the pin fitting hole 57 and the mold is clamped, the Thus, the sliding core 52 can be advanced in the mold clamping direction against the force of the spring 55.

[0004]

However, the mechanism for preventing displacement as described above has a side key guide 53 for positioning the sliding core 52 in the lateral direction when the sliding core 52 moves to the mold clamping position. Since the position 53 is away from the position of the core pin 54, there is a problem that even a slight deflection of the side key guide 53 causes a large dimensional difference in the product portion. Incidentally, the clearance e between the side key guide 53 and the sliding core 52 is about 0.10 to 0.12 mm. Also,
Since the side key guide 53 is separated from the cavity, it is difficult to follow the thermal change of the cavity, and the dimensional accuracy in the lateral direction is easily deteriorated by the thermal change. For these reasons, conventionally, there is a problem that a machining hole becomes large because a cast hole smaller than about 0.5 to 1 mm is formed and processed in a subsequent process.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve the positioning accuracy of a sliding core in a mold-clamped state and reduce a machining margin. is there.

[0006]

In order to achieve the above object, the present invention provides a sliding core according to claim 1, which moves forward and backward with opening and closing of a mold and has an undercut forming portion on the front side. In the positioning device, when in the tightened state, the sliding core is positioned by the displacement prevention mechanism.
A position-fitting prevention mechanism is provided between an abutting surface provided on a part of the front surface of the sliding core and a receiving surface of a mold facing the abutting surface in a mold-clamped state. In addition to being formed by the joint , the sliding core also serves as a guide for sliding .

As described above, the fitting portion is provided on the abutting surface of the sliding core and the receiving surface of the mold, and the fitting portions are fitted to each other to perform positioning in the lateral direction. The part can be made closer to the undercut formed part, and the error of the fitting part does not lead to a large dimensional error of the undercut formed part. Here, the prevention of displacement is mainly to prevent displacement in a direction intersecting the sliding direction of the sliding core. The undercut portion includes a core pin, a blanking pin, a projection for forming an undercut shape, and other various shapes.

Further, the displacement prevention mechanism, so causing also serves as guide during sliding of the slide core, the sliding of the slide core becomes smooth and simple as possible construction of the device.

According to a second aspect of the present invention, the receiving surface of the mold is formed in a cavity mold that directly defines a cavity. If the receiving surface of the mold is formed in the cavity mold in this manner, the misalignment prevention mechanism can easily follow the change in heat of the cavity, and deterioration in dimensional accuracy due to the change in heat is suppressed.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a plan view of a sliding core provided on the upper surface of the lower mold and an explanatory view of a state where the sliding core is advanced in a mold clamping direction, and FIG. 2 is a mold in which a portion corresponding to line AA in FIG. It is sectional drawing of the metal mold | die of a clamped state.

[0011] The sliding core positioning device according to the present invention comprises:
As shown in FIG. 1, the sliding core 2 provided on the upper part of the lower die 1 is guided, and the sliding core 2 moved to the clamped state can be positioned. 2 is provided with a core pin 3 as an undercut forming part on the front surface, and a rod 4 extending along the sliding direction is connected to the rear surface side. The spring support member 5 to be connected is slidably penetrated.

A nut member 6 is connected to the base end of the rod 4. A spring 7 is interposed between the nut member 6 and the spring support member 5 to retreat the sliding core 2. Biased in the direction. The sliding core 2 is provided with a pin fitting hole 8 that penetrates vertically and diagonally.
The lower mold 1 is provided with a cavity molding die 9 for forming the cavity C.

On the other hand, an upper mold 11 has a cavity forming mold 12 for forming a cavity C, an inclined pin 13 which can be fitted in the pin fitting hole 8, and a rear surface of the sliding core 2 in a mold-clamped state. When the upper die 11 is clamped, the inclined pin 13 is fitted into the pin fitting hole 8, the sliding core 2 advances, and the core pin 3 projects into the cavity C. At the same time, the sliding core 2 is
When the mold is opened, the sliding core 2 is retracted and the core pin 3 is retracted from the cavity C to the outside.

On the front side of the sliding core 2, FIG.
Abutment surface 2k as shown in FIG. 1 is provided, and opposed to this abutment surface 2k, cavity molding die 9 on the lower die 1 side.
Is formed with a receiving surface 9u. The abutting surface 2k and the receiving surface 9u regulate the maximum forward position of the sliding core 2, and a displacement prevention mechanism 15 is provided between the abutting surface 2k and the receiving surface 9u. Is provided.

The displacement prevention mechanism 15 is provided with a sliding core 2
A positioning pin 16 as a fitting portion attached to the abutment surface 2k of the above, and a positioning hole 17 as a fitting portion engraved on the receiving surface 9u of the cavity forming die 9. The positioning pin 16 is inserted into the positioning hole 17. The fitting prevents the position from shifting in the left, right, up, and down directions. At this time, the axial lengths of the positioning pin 16 and the positioning hole 17 are set to such a length that a sliding guide is performed when the sliding core 2 slides.

Incidentally, the positioning pin 16 and the positioning hole 17 at this time have the diameter of the positioning pin 16 in the embodiment of 30 mm-0.007 to 30 mm-0.020, and the diameter of the positioning hole 17 is 30 mm. ± 0-30mm
+0.021.

In the positioning device configured as described above, since the displacement prevention mechanism 15 is provided close to the core pin 3, the displacement of the displacement prevention mechanism 15 is amplified and transmitted to the core pin 3. Situation can be suppressed. Further, since the displacement prevention mechanism 15 is configured to include the cavity molding die 9, it is possible to suppress a thermal error or the like following the thermal change of the cavity C.

The present invention is not limited to the above embodiment. Those having substantially the same configuration as those described in the claims of the present invention and exhibiting the same operation and effect belong to the technical scope of the present invention. For example, the positioning pin 15 of the sliding core 2 and the positioning hole 16 of the cavity mold 9 may be either pins or holes. Further, the shape of the undercut molded portion may be a shape other than the core pin 3.

[0019]

As described above, in the sliding core positioning apparatus according to the present invention, a position shift preventing mechanism for preventing a position shift of the sliding core is provided during sliding. Since it is constituted by the abutment surface of the child and the fitting portion provided on the receiving surface of the mold, the fitting portion can be close to the undercut forming portion, and the error of the fitting portion is large in the undercut forming portion. No dimensional error. For this reason, the processing allowance in the post-process can be reduced. Further, since the guide also serve also as during sliding of the sliding core to the displacement prevention mechanism, the sliding of the slide core becomes smooth and simple as possible construction of the device. If the receiving surface of the mold is formed in the cavity mold as in claim 2, the displacement prevention mechanism can easily follow the thermal change of the cavity, and the deterioration of the dimensional accuracy due to the thermal change is suppressed.

[Brief description of the drawings]

FIG. 1 is a plan view of a sliding core provided on an upper surface of a lower mold, and is an explanatory view of a state in which the sliding core has advanced in a mold clamping direction.

FIG. 2 is a cross-sectional view of a mold in a mold-clamped state in which a portion corresponding to line AA in FIG.

FIG. 3 is a plan view showing a state in which a sliding core provided on a lower mold has advanced in a mold clamping direction;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

[Explanation of symbols]

2: sliding core, 2k: abutting surface, 3: core pin, 9: cavity forming die, 9u: receiving surface, 15: misalignment prevention mechanism, 16: positioning pin, 17: positioning hole, C: cavity.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideo Hazegawa 1500, Hirakawa, Otsu-cho, Kikuchi-gun, Kumamoto Prefecture Honda Motor Co., Ltd. Kumamoto Factory (56) References JP-A-6-328215 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 17/22 B22D 17/24 B29C 33/76 B29C 45/26

Claims (2)

(57) [Claims] When a sliding core that moves forward and backward with the opening and closing of a mold and has an undercut forming part on the front side is in a mold-clamped state, the sliding core is positioned by a displacement prevention mechanism. In the positioning device, the displacement prevention mechanism includes a contact surface provided on a part of a front surface of the sliding core, and a receiving surface of a mold facing the contact surface in a mold-clamped state. It is constituted by a fitting part that can be fitted between
A sliding core positioning device, which also serves as a guide for sliding the sliding core. 2. The positioning device for a sliding core according to claim 1, wherein the receiving surface of the mold directly defines a cavity.
A positioning device for a sliding core, which is formed in a cavity forming die to be formed .