JP2594318Y2 - Mold - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a mold.
Things.

[0002]

2. Description of the Related Art Conventionally, when forming a molded product a such as a dust cover shown in FIG. 5, a molding die shown in FIG. 6 is used. That is, reference numeral 1 denotes a lower die, reference numeral 2 denotes an upper die movably combined with the lower die 1, and reference numeral 3 denotes a middle die slidably combined with the lower die 1.
A cavity 4 is provided by the molds 2 and 3 at the time of mold clamping, and an annular gate 6 for communicating the sprue 5 and the cavity 4 is provided between the upper mold 2 and the middle mold 3.

[0003]

In the above prior art, the upper mold 2 and the middle mold 3 are not in contact with each other, and are indirectly positioned with each other by being positioned with respect to the lower mold 1. Not just. Therefore, the upper mold 2 and the middle mold 3 are likely to be displaced from each other with respect to the positioning. When the two 2 and 3 are displaced in the horizontal direction in the drawing, the annular gate 6 cannot be kept at the same width over the entire circumference. .
When a wide portion and a narrow portion are formed in the annular gate 6 in this manner, when a burr (not shown) is torn off from the molded product a at the gate 6 portion as a boundary after molding, a large portion is formed at the wide portion. Burrs may remain without being cut well. To solve the above problem,
The applicant has previously filed Japanese Utility Model Application No. 1-88621 (Japanese Utility Model Application Laid-Open No. 3-3).
No. 1526),
Outside of multiple protrusions projecting upward from the upper end of the medium size
A fitting part is provided to allow the peripheral surface to slidably contact the inner peripheral surface of the upper die.
The outer peripheral surface of the projection at this fitting portion and the inner peripheral surface of the upper die
The upper mold and the middle mold are positioned directly to each other by fitting.
A proposed mold was proposed. And according to this mold,
The upper die and the middle die are positioned directly at the time of die clamping by mating.
Therefore, the width of the annular gate formed between both split molds must be
It can be uniformed over the circumference. However, this
As described above, in the mold of
The protruding part protruding toward
Due to the structure that slidably contacts the inner peripheral surface,
The strength of the protruding part is
May be insufficient. This corresponds to this upward projection.
From the upper die on the outer periphery to the upper die
When the load due to the displacement of the mold is input, the upward projection
Since there is no support on the inner peripheral side, this upward projection is
Because it must be subjected to this load.
If the foot is extreme, the upward projection should lean inward
May be damaged. The present invention is based on the above points.
Protruding part provided in the fitting part that positions the upper die and the middle die
Can increase the strength of the
To provide a mold capable of preventing damage
With the goal.

[0004]

Means for Solving the Problems To achieve the above object,
Therefore, the mold of the present invention is
Upper mold and a middle mold slidably combined with the lower mold.
And an annular gate is provided between the upper mold and the middle mold.
The upper mold and the middle mold are fitted to each other at the time of mold clamping.
In a molding die provided with a mating part, the fitting part may be the upper mold
Of multiple protrusions protruding toward the inner circumferential direction on the inner circumferential surface of
In an end face which is slidably in contact with the outer peripheral surface of said medium-sized
I decided to be.

[0005]

In the mold of the present invention having the above structure,
The protrusion protruding from the inner peripheral surface of the upper die toward the inner peripheral direction
The tip surface (inner surface) is slidably connected to the outer surface of the medium-sized mold.
Because of the touching structure, this inward projection is
A part of the circumference due to misalignment.
It does not tilt even if it hits the outer peripheral surface. this
Is the load input to this protrusion in the direction of the protrusion?
And projecting direction as in the mold according to the above-mentioned prior application.
This is because loads are not input in the orthogonal direction.
You.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In FIG. 1, reference numeral 1 denotes a lower die, reference numeral 2 denotes an upper die which is freely combined with the lower die 1, and reference numeral 3 denotes a lower die 1.
The split molds 1 , 2 and 3 are provided with a cavity 4 at the time of mold clamping, and an annular ring communicating the sprue 5 and the cavity 4 between the upper mold 2 and the middle mold 3. Gate 6 is provided. Then, between the sprue 5 and the gate 6, the upper mold 2 and the middle mold 3
A fitting portion 7 that fits with each other at the time of mold clamping as shown in an enlarged manner is provided, and this fitting portion 7 is provided on the inner circumferential surface of the upper mold 2 in the inner circumferential direction as shown in FIG. The end faces 9 of the plurality of protrusions 8 protruding toward the outer surface of the middle die 3 are slidably contacted with each other. In the figure, the protrusions 8 are arranged in four equal parts, and a substantially fan-shaped material flow path 1 is provided between the protrusions 8.
0 is provided.

According to the molding die having the above structure, the upper gate 2 and the middle die 3 can be fitted to each other and directly positioned by the fitting portion 7 when the mold is clamped. Can be kept the same width over the entire circumference. Therefore, when the burr (not shown) is torn off from the molded product a at the gate 6 portion as a boundary after molding, the burr can be cut uniformly over the entire circumference, and the burr remains on the molded product a. Can be prevented. In addition to this,
Fitting provided for positioning upper mold 2 and middle mold 3
The part 7 is provided on the inner peripheral surface of the upper die 2 so as to protrude toward the inner peripheral direction.
The tip surfaces 9 of the plurality of protrusions 8 are slidable on the outer peripheral surface of the middle mold 3.
To be brought into contact with the inner circumferential surface of the upper mold 2 in the inner circumferential direction.
The protrusion 8 protruding toward the medium-sized
This structure is slidably in contact with the outer peripheral surface of
The inwardly projecting portion 8 is caused to move around the circumference due to the displacement of the upper mold 2 and the lower mold 3.
Abuts the outer peripheral surface of the middle die 3 with its tip surface 9
Even if it is, it does not deform so as to tilt. Therefore
This is provided for positioning the upper mold 2 and the middle mold 3.
The strength of the protrusion 8 can be increased, and the protrusion 8 is damaged.
Can be prevented.

The lower mold 1 and the upper mold 2 may each be further divided into two as shown in FIG. In addition, the middle mold 3 is divided into two in FIG. 1 and provided with an air passage 11 for release between the divided bodies. However, as shown in FIG. 4, the middle mold 3 may be an integral body without an air passage. .

[0010]

[Effects of the Invention] The present invention has the following effects. That is, the fitting portion fitted to each other when the upper die and medium in clamping provided, in order to have so as to position directly fitted to the upper die and medium together with the fitting portion, an annular gate entire circumference Over the same width. Therefore, when the burrs are torn off from the molded article at the gate portion after the molding, the burrs can be cut uniformly over the entire circumference, and the burrs can be prevented from remaining on the molded article.
In addition to this, in order to position the upper mold and the middle mold,
The provided fitting part is directed toward the inner circumferential direction on the inner circumferential surface of the upper die.
Slide the tip surfaces of the projecting protrusions onto the outer peripheral surface of the
The upper die in the inner circumferential direction
The protruding part protruding toward
Because of the structure that slidably contacts the peripheral surface, this inward
The protrusion of the part is part of the circumference due to the displacement of the upper mold and the lower mold,
Even if the tip surface is hit against the outer peripheral surface of the medium size, it tilts
There is no deformation. Therefore, the upper die and the middle die
Increase the strength of this protrusion provided for positioning
Can prevent this projection from being damaged.
Wear.

[Brief description of the drawings]

FIG. 1 is a sectional view of a mold according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a half sectional view of a molding die according to another embodiment of the present invention.

FIG. 5 is a half sectional view of a molded product.

FIG. 6 is a half sectional view of a molding die according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower mold 2 Upper mold 3 Middle mold 4 Cavity 5 Sprue 6 Gate 7 Fitting part 8 Protrusion 9 Tip surface 10 Material flow path 11 Air passage

Claims (1)

(57) [Scope of request for utility model registration] 1. A lower mold (1) to the contact and separation freely combined upper mold (2), and a slidably combined middle- to said lower die (1) (3), the upper type (2) and the medium-sized (3) an annular gate (6) provided between the front Kijo type (2) and the medium-sized (3) a fitting portion to be fitted to each other during clamping in the (7) In the provided molding die, the fitting portion (7) is provided on an inner peripheral surface of the upper die (2) in an inner circumferential direction.
Tip surface (9) of a plurality of protrusions (8) protruding toward the direction
Slidably contacting the outer peripheral surface of the middle die (3)
Mold, characterized in that it.