JPH0375108A - Metal mold - Google Patents

Abstract

PURPOSE:To sufficiently secure th positioning precision of an insert die at at low cost by positioning the insert die of the inner circumferential side of a sleeve at least in three places of the circumferential direction of the sleeve via a perforation member which perforates the sleeve in the radial direction. CONSTITUTION:Three projecting parts 16a perforate a sleeve 18 in the intervals of 120 deg. and is lengthened to the radial direction and formed to the outer circumferential faces of the liners 16. The outer circumferential faces of these projecting parts 16a are brought into facial contact with the inner circumferential face of a retainer plate 20 and thereby the positioning of the radial direction of the liners 16 is performed. Further the positioning of the axial direction of the insert die 16 is performed by being pinched between the retainer plate 20 and a back plate 22 fixed to the rear side thereof. On the other hand, in order to prevent interference of the insert die 16 with the projecting parts 16a, three notched parts 18a lengthened to the direction of axial line of the sleeve 18 are formed in the intervals of 120 deg. excepting the tip part thereof. This sleeve 18 is inserted from the right sides of the insert die 16 and fixed to an ejector plate by bolt clamping in the left end part thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold equipped with a sleeve for ejecting a molded product.

(Prior Art) In injection molds and the like, a mold structure in which a sleeve protrudes is sometimes adopted due to shape constraints of the molded product or a request to prevent molded product deformation due to protrusion. In a mold equipped with such a sleeve, for example, as shown in FIG. Since it is movably provided, a predetermined clearance is formed between the sleeve 2 and the insert 4 and between the sleeve 2 and the mold body 6, as shown in FIG. 5, for example.
Further, the insert 4 is fixed at its root portion to the insert mounting plate 7 and the movable side mounting plate 8, which are integrally formed with the mold body 6.

(Problems to be Solved by the Invention) In such a mold, the positioning accuracy of the tip of the insert in a plane perpendicular to the sleeve sliding direction is insufficient;
At the maximum width, there will be variation in the total of the above two types of clearance. The following three measures can be considered to reduce this variation.

■ Reduce the above clearance.

■ Improve the accuracy of attachment of the base of the insert to the insert mounting plate and movable side mounting plate.

(2) Form a taper at the tip of the insert, and use the taper to position it with the mating mold when the mold is closed.

However, in the countermeasure (2) above, galling is likely to occur due to sliding, and there is a problem in mold durability. Furthermore, as long as there is a clearance, variations are inevitable and there is no fundamental solution.

In the countermeasure (2) above, it is difficult to maintain high precision because it is affected by thermal distortion and collapse of the mold, and if this is attempted, the cost of the mold will increase. In the countermeasure (■) above, it is necessary to ensure sufficient height accuracy of the insert in order to perform positioning using the taber, but it is difficult to achieve this. Mold cost increases.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a mold that is low cost and can ensure sufficient positioning accuracy of the insert on the inner peripheral side of the sleeve. It is something.

(Means for Solving the Problems) The mold according to the present invention has a configuration in which the insert and the mold body are positioned by direct contact through a penetrating member that penetrates the sleeve in the radial direction, thereby achieving the above-mentioned It was designed to achieve the goal.

That is, in a mold in which a sleeve for ejecting a molded product is slidably provided between an insert located on the inner peripheral side of the sleeve and a mold body located on the outer peripheral side of the sleeve,
The insert is positioned with respect to the mold body at at least three positions in the circumferential direction of the sleeve via a penetrating member passing through the sleeve in a radial direction of the sleeve, and the insert is provided with a penetrating member in the sleeve. The invention is characterized in that a notch is formed over at least a stroke range of the molded product protrusion to prevent interference.

The above-mentioned "penetrating member" is not particularly limited in shape, material, etc., as long as the insert can be positioned in the radial direction with respect to the mold body. , it may be constructed as a separate member from the insert and the mold body, or it may be constructed integrally with the insert or the mold body.

The above-mentioned "at least three locations" are not particularly limited to the angular spacing between them, as long as the insert is positioned in any radial direction relative to the mold body. do not have. Furthermore, it goes without saying that the same number of penetrating members may be provided corresponding to each of the above-mentioned "at least three" locations, but one penetrating member may be responsible for positioning at two or more locations. .

(Function) As shown in the above configuration, the insert on the inner circumferential side of the sleeve is positioned relative to the mold body at at least three locations in the circumferential direction of the sleeve via the penetrating member that penetrates the sleeve in the radial direction. Therefore, the insert and the mold body are positioned by direct contact at a portion relatively close to the tip of the insert.

(Effects of the Invention) Therefore, according to the present invention, the insert on the inner circumferential side of the sleeve can be positioned with high accuracy with respect to the mold body on the outer circumferential side of the sleeve with the alignment accuracy of ordinary molds. That is,
Sufficient positioning accuracy of the insert can be ensured at low cost.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of a main part of an embodiment of a mold according to the present invention, and FIGS. 2 and 3 are a cross-sectional view taken along the line ■-■ and a cross-sectional view taken along the line ■-■.

This mold is an injection mold for molding a plastic lens, and as shown in FIG. 1, molten resin is injected into a cavity 14 formed by a fixed mold 10 and a movable mold 12. It is designed to mold lenses with flanges. The cavity 14 is defined by a lens curved surface forming part 14a for forming a lens curved surface and a flange forming part 14b for forming a flange around the lens curved surface. Child 1
The flange forming portion 14b is formed on the distal end surface of the sleeve 18 and the inner peripheral surface of the mold plate 20 (mold body).

In order to take out the flanged lens, which is a molded product after injection molding, from the movable mold 12, the sleeve 18 is moved a predetermined distance to the right from the position shown in FIG. 1, and presses the flanged lens. This makes it stick out. For this reason, the sleeve 18 is provided so as to be slidable between the insert 16 located on its inner circumferential side and the template 20 located on its outer circumferential side. between the sleeve 18 and the insert 16 and between the sleeve 18 and the template 20.
A predetermined clearance is formed between each of them.

The insert 18 has the lens curved surface forming portion 1 on its tip surface.
4a is formed, it is important that the lens curved surface forming portion 14a of the fixed mold 10 be directly opposed to the lens curved surface forming portion 14a with high precision.Therefore, it is necessary to ensure sufficient positioning accuracy in the radial direction. .

Therefore, in this embodiment, as shown in FIGS. 2 and 3, three convex portions lea (penetrating The outer circumferential surfaces of these convex portions lea come into surface contact with the inner circumferential surface of the template 20 to position the insert t6 in the radial direction. Further, the insert 16 is positioned in the axial direction by being held between the template 20 and a back plate 22 fixed to the back side thereof. On the other hand, the sleeve 18 has the insert 16
In order to prevent the sleeve 18 from interfering with the convex portion 16a, three notches 18a extending in the axial direction of the sleeve 18 are formed at intervals of 120' apart from the tip thereof. This sleeve 18 is inserted from the right side (parting surface side) of the insert 16, and is fixed at its left end to an ejector plate (not shown) by bolting. Note that the back plate 22 has three holes formed through which the sleeve 18 is inserted.

As described in detail above, according to this embodiment, the input 16
Since the sleeve 18 is in direct surface contact with the template 20 to determine its position in the radial direction, the sleeve 18
Even if a required clearance is formed inside and outside of the lens curved surface forming portion 14 of the tip surface of the insert 16,
a can be made to directly face the lens curved surface forming portion 14a of the fixed type lO with high precision, thereby making it possible to sufficiently improve the quality of the flanged lens. Moreover, in this embodiment, the above-mentioned effects can be achieved at low cost since exceptionally high machining accuracy is not required in manufacturing the mold.

Further, the sleeve 18 has the notch 18a formed over a length longer than the stroke range of the sleeve 18 to prevent interference with the convex portion lea of the insert te. The above effects can be achieved without impairing the molded product ejection function of the sleeve 18.

When the mold shown in this example was actually produced, it was found that the variation in positional deviation between the lens curved surface forming portion 14a of the fixed mold 10 and the lens curved surface forming portion 14a of the movable mold 12 was We were able to reduce the number of micrometers around the front and back of the door to a few micrometers, which is close to the limit of machining accuracy.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of essential parts showing an embodiment of a mold according to the present invention, Fig. 2 is a cross-sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a cross-sectional view taken along the line ■-■ in Fig. 1. 4 is a sectional view showing a conventional example, and FIG. 5 is an enlarged view of the V section in FIG. 4. 1B...Insert lea...Convex part (penetrating member) 18...Sleeve Hla...Notch part 20...Mold plate (mold body)

Claims (1)

[Claims] A mold in which a sleeve for ejecting a molded product is slidably provided between an insert located on the inner peripheral side of the sleeve and a mold body located on the outer peripheral side of the sleeve. The insert is positioned relative to the mold body at at least three locations in the circumferential direction of the sleeve via penetrating members that pass through the sleeve in a radial direction of the sleeve, and A mold characterized in that a notch portion for preventing interference with a member is formed over at least a stroke range of the molded product protrusion.