JP2010137427A - Injection molding mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding mold capable of preventing the end surface of a pushing-up block, which is left protruding from a parting line on the side of one mold, from being damaged by the edge of the other mold during clamping. <P>SOLUTION: Although the pushing-up block 4 is left protruding from the parting line PL on the side of a core mold 1 after release of a molding A by a coil spring 7, a pushing-back block 10 of a cavity mold 2, when fastened, butts against the end surface of the pushing-up block 4, and the pushing-up block 4 is pushed back to a position flush with the parting line PL on the side of the core mold 1, avoiding damage of the pushing-up block 4 by the impact of the edge C of the cavity mold 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection mold used for molding various resin molded products.

  FIG. 3 shows a conventional injection mold, and this injection mold includes a pair of molds, that is, a core mold 1 and a cavity mold 2. For example, the cavity mold 2 is a cylinder not shown. The mechanism moves up and down to clamp and open the mold.

  The core mold 1 is provided with an ejector pin 3 that controls the release (mold removal) of a resin molded product (hereinafter simply referred to as a molded product) A. After the core mold 1 and the cavity mold 2 are opened, The ejector pin 3 is moved upward by a cylinder mechanism (not shown) so that the molded product A is pushed up from the molding surface 1a of the core mold 1 and released.

Like the molded product A molded by this injection mold, the _one having the side wall portion A ₂ that is gently inclined with a relatively long extending length from the peripheral edge of the general portion A ₁ , the above-mentioned at the time of mold release When locally pushes up the general portion a ₁ by the ejector pins 3, as the load of the portion corresponding to the ejector pins 3 end is increased, and whitening occurs internal stress in the general portion a ₁ of the molded article a It is well known.

Therefore, as a measure for preventing whitening of the molded product general part A ₁ due to the push-up of the ejector pin 3, the core mold 1 corresponds to the terminal A ₃ of the side wall part A ₂ of the molded product A as shown in FIG. The push-up block 4 is disposed at a position where the molded product A is released, and the push-up block 4 is operated in synchronization with the ejector pin 3 when the molded product A is released. The push-up block 4 allows the terminal A ₃ of the molded product A to be by pushing up the general section at the same time as the push-up of a ₁ by the ejector pins 3, to avoid an increase in the load in the portion corresponding to the ejector pins 3 end of the general portion a ₁ is being performed.

  The end face of the push-up block 4 is formed in line with a parting line P · L formed by the mating surfaces of the core mold 1 and the cavity mold 2.

The parting line P · L is formed as an inclined surface that is substantially orthogonal to the end portion of the molded product A, that is, the side wall portion A _2, and accordingly, the terminal A ₃ of the molded product A is the end surface of the push-up block 4. by a part, it is substantially perpendicular to form a side wall portion a _2.

By the way, when the molded product A is molded with the core mold 1 and the cavity mold 2 as described above, after the core mold 1 and the cavity mold 2 are opened, the molded product A is thermally shrunk and the terminal A ₃ becomes the core. A phenomenon of floating about 1-2 mm from the parting line P / L on the mold 1 side occurs.

Thus, when the terminal A ₃ of the molded article A is thereby lifted from the parting line P · L of the core mold 1 side (mating surface of the core mold 1), wherein upon release of the molded article A as described above pushing the push-up block 4 operates synchronously with the ejector pins 3, ejector pins 3 to per-out earlier general portion a ₁ of the molded article a, the end, again localized load increase in the general section a ₁ It is generated, bleaching to the general portion a ₁ is generated.

Therefore, as shown in FIG. 3, a coil spring 7 is interposed as a biasing means between the lower end of the pin 5 of the push-up block 4 and the ejector plate 6, and the core mold 1 and cavity mold 2 are When the mold is opened, the push-up block 4 can be protruded from the parting line P · L by a lift amount corresponding to the lift amount a of the terminal A ₃ by the spring force of the coil spring 7. .

This similar structure is disclosed in Patent Documents 1 and 2, for example.
JP 2002-321251 A JP 2001-310354 A

  In the conventional structure, the core mold 1 and the cavity mold 2 are opened, and the ejector pin 3 and the push-up block 4 are moved up synchronously by the forward movement of a cylinder mechanism (not shown) to form the molded product A as a core. When the cylinder mechanism is moved backward after being released from the mold 1, the ejector pin 3 is returned to a position where the end surface thereof is flush with the molding surface 1 a of the core mold 1, but the push-up block 4 is moved to the coil spring 7. Due to the spring force, the lift amount remains protruding from the parting line P / L (the mating surface of the core mold 1) on the core mold 1 side.

Therefore, when the core mold 1 and the cavity mold 2 are clamped again, the molding surface 2a of the cavity mold 2 and the parting line P • L (the mating surface of the cavity mold 2) on the cavity mold 2 side are used. The edge C formed may abut against the end face of the raised push-up block 4 and damage the end face due to the difference in hardness from the cavity mold 2, which may cause molding failure of the terminal A ₃ when the molded product A is molded. .

  Therefore, the present invention provides an injection mold that can prevent the end face of the push-up block that remains protruding from the parting line on one mold side from being damaged by the edge part of the other mold during mold clamping. A type is provided.

  In the present invention, a pair of molds to be clamped and opened, and one of these molds is disposed at a position corresponding to the end of the molded product, and synchronous with the ejector pin when the molded product is released. And a push-up block that pushes up the end of the molded product, and the push-up block is attached to the parting line of the molds by a predetermined amount when the pair of molds are opened by the biasing means. In the biased injection mold, the other of the pair of molds is disposed so as to protrude and retract so as to face the push-up block, and before the push-up block is clamped when the pair of molds are clamped A push-back block is provided that hits and pushes the push-up block back to a position that is flush with the parting line.

  The push-up block remains protruding by a predetermined amount from the parting line on one mold side even after the molded product is released by the urging means, but when the mold is clamped, the push-back block on the other mold Comes into contact with the end face of the push-up block and is pushed back to a position where the push-up block is flush with the parting line on one mold side.

  According to the present invention, the push-up block that remains protruding from the parting line of one mold after the molded product is released is separated by the push-back block of the other mold when the mold is clamped. As a result, the end surface of the push-back block can be prevented from colliding with the edge formed by the molding surface of the other mold and the parting line and being damaged.

  As a result, a molded product with high molding quality can be obtained without causing molding defects at the end of the molded product.

  Hereinafter, an embodiment of the present invention will be described in detail with the same reference numerals assigned to the same parts as those of the conventional configuration together with the drawings.

  FIG. 1 is a cross-sectional view showing a mold opening state of an injection mold according to the present invention, and FIG. 2 is a cross-sectional view showing a mold clamping state of the injection mold.

  As shown in FIG. 1, the injection mold according to this embodiment includes a pair of molds, that is, a core mold 1 and a cavity mold 2. For example, the cavity mold 2 is raised by a cylinder mechanism (not shown). , Moved down, clamped and opened.

  The core mold 1 is provided with an ejector pin 3 that controls the release of the molded product A. After the core mold 1 and the cavity mold 2 are opened, the ejector pin 3 is moved up by a cylinder mechanism (not shown). Thus, the molded product A is pushed up from the molding surface 1a of the core mold 1 and released.

In order to prevent local whitening of the molded product general part A ₁ due to the pushing up of the ejector pin 3, an ejector is provided at a position corresponding to the terminal A ₃ of the side wall part A ₂ of the molded product A on the core mold 1. A push-up block 4 that pushes up the terminal A ₃ in synchronism with the pin 3 is provided.

  The push-up block 4 is connected to the ejector plate 6 of the ejector pin 3 via a pin 5.

  The ejector plate 6 is provided with a small chamber 6a for accommodating an upper limit position regulating stopper 5a provided at the lower end of the pin 5.

A coil spring 7 as an urging means is interposed between the bottom of the small chamber 6a and the stopper 5a, and the push-up block 4 is moved by the spring force of the coil spring 7 to the parting line P on the core mold 1 side. · from L (mating surface of the core mold 1), and is capable projecting lift amount corresponding to the floating amount a of the terminal a ₃ due to thermal shrinkage of the molded article a.

  The above basic structure is exactly the same as the conventional structure.

  Here, in the present embodiment, the cavity mold 2 is provided with a push-back block 10 of the push-up block 4 facing the push-up block 4 provided on the core mold 1.

  When the core mold 1 and the cavity mold 2 are clamped, the push-back block 10 is brought into contact with the push-up block 4 and the push-up block 4 is moved to the parting line P • L (core mold on the core mold 1 side). 1 to a position that is flush with the mating surface of the cavity mold 2, and from the parting line P • L (the mating surface of the cavity mold 2) on the cavity mold 2 side to the small chamber 2 b provided in the cavity mold 2. It is arranged so as to protrude and retract.

  The push-back block 10 is provided at the end of a pin 11 having a lower limit position restricting stopper 11a at the upper end, and is in a normal state by a spring force of a coil spring 12 as an urging means disposed in the small chamber 2b. It is biased in a direction protruding from the parting line P / L on the cavity mold 2 side.

The spring force P ₂ of the push-back block 10 of the coil spring 12, the greater than the spring force P ₁ of the push-up block 4 side of the coil spring 7 (P _{2> P 1)} have been set, when the mold clamping, When the push-up block 4 is pushed by the push-back block 10 and is pushed back to the position where it is flush with the parting line P / L on the core mold 1 side, the coil spring 12 is pressed by the reaction force of the push-up block 4 thereafter. It is immersed in the small chamber 2b against the spring force.

  In the present embodiment, the mutual contact surfaces (end surfaces) of the push-up block 4 and the push-back block 10 are surfaces with respect to the mold release direction of the molded product A, that is, the vertical direction in the present embodiment. It is formed directly.

Specifically, the end surface of the push block 4 is one side corresponding to the terminal A ₃ of the side wall portion A ₂ of the molded article A constitutes a part of the cavity, the terminal A ₃ of the molded article A in one side is the same as the parting line P · L angle of the end face so as to be substantially perpendicular to form a side wall portion a _2, is formed as an inclined surface that is substantially perpendicular to the side wall portion a _2. And the said push-back block 10 is set as the arrangement configuration which surface-contacts to the whole area | region other than the inclined one side part which comprises a part of said cavity in the end surface of the said push-up block 4, Therefore, in this embodiment, The entire region other than the one side portion of the end surface of the push-up block 4 and the entire end surface of the push-back block 10 are formed substantially horizontally with respect to the parting line P · L.

In the molded product A formed by the injection mold of the present embodiment having the above-described configuration, when the core mold 1 and the cavity mold 2 are opened, the terminal A ₃ of the side wall portion A ₂ is shown in FIG. Thus, it floats from the parting line P · L on the core mold 1 side with the contraction amount indicated by the symbol a.

The opening of the mold and the core mold 1 and the cavity mold 2, the push block 4 from the core mold 1 side of the parting line P · L is by the spring force of the coil spring 7, floating amount of the molded article terminal A ₃ a substantially corresponding to the projecting lift amount, one side of the end face of the push-up block 4 is in a state of contact with or in proximity to the molded part terminal a ₃ which floated above the.

Accordingly, after the mold opening is completed, when moved upward by actuating synchronously with the block 4 push the ejector pins 3, at the same time push the general portion A ₁ of the molded article A by the ejector pins 3, the end surface of the push-up block 4 The molded product terminal A ₃ can be pushed up at one side to release the molded product A from the molding surface 1 a of the core mold 1.

Therefore, the general portion the portion corresponding to the ejector pins 3 of A ₁ of the molded product A, the load that the locally whitening phenomenon occurs in the internal stress is avoided by increasing the same manner as the conventional structure It is.

  In this embodiment, after the molded product A is released as described above, the lift block 4 is lifted from the parting line P / L on the core mold 1 side by the spring force of the coil spring 7. However, when the core mold 1 and the cavity mold 2 are clamped again, the push-back block 10 on the cavity mold 2 side comes into contact with the push-up block 4 and FIG. As shown in FIG. 2, the push-up block 4 is pushed back to a position where it is flush with the parting line P / L on the core mold 1 side.

  Therefore, at the time of clamping, the edge portion C formed by the molding surface 2a of the cavity mold 2 and the parting line P / L on the cavity mold 2 side abuts against the end face of the lifted push-up block 4, and the cavity It is possible to avoid the end face from being damaged due to the difference in hardness from the mold 2.

As a result, without causing defective molding to the terminal A ₃ of the molded article A, it is possible to obtain a high molding quality molded article A.

Further, in the present embodiment, the spring force P ₂ of the push-back block 10 of the coil spring 12, so is set larger than the spring force P ₁ of the push-up block 4 side of the coil spring 12, sometimes open the mold, The state where the push-up block 4 is pushed back is maintained up to a predetermined position where the lift stroke of the cavity mold 2 is increased to some extent (corresponding to the spring stroke of the coil spring 12).

Therefore, the protruding action of the push-up block 4 can be suppressed until the side wall A ₂ of the molded product A is thermally contracted and the terminal A ₃ is lifted by the contraction amount a. projects operated simultaneously with the opening, can be avoided from occurring a situation which would deform the terminal a ₃ and the side wall portion a ₂ of the molded article a.

  Further, since the mutual contact surfaces (end surfaces) of the push-up block 4 and the push-back block 10 are formed to be perpendicular to the mold release direction of the molded product A, when the push-up block 4 is pushed back by the push-back block 10. The pushing back force of the pushing back block 10 (the spring force of the coil spring 12) all acts in the operating direction of the pushing up block 4, that is, the axial direction of the pin 5, so that the pushing block 4 and the pin 5 and the core mold 1 There is no twisting phenomenon between them, and the push-up block 4 can be smoothly pushed back.

  Further, if the mutual contact surfaces of the push-up block 4 and the push-back block 10 are formed in a plane with respect to the mold release direction of the molded product A, the contact surfaces are connected to the parting lines P and L. Compared with the case of forming the same surface, there is an advantage that the workability is much better and the processing accuracy is easily obtained.

In the embodiment described above, the parting lines P and L of the core mold 1 and the cavity mold 2 are formed so as to be inclined so that the terminal A ₃ is formed at a substantially right angle with respect to the side wall portion A ₂ of the molded product A. However, the present invention can also be applied to those in which the parting lines P and L are set horizontally.

  In addition, although the mold clamping and mold opening of the core mold 1 and the cavity mold 2 are in the vertical direction, it can also be applied to a lateral type.

Sectional drawing which shows the mold open state of one Embodiment of this invention. Sectional drawing which shows the clamping state of one Embodiment of this invention. Sectional drawing which shows the conventional injection mold.

Explanation of symbols

1 ... Core mold (one mold)
2 ... Cavity mold (the other mold)
3 ... Ejector pin 4 ... Push-up block 7 ... Coil spring (biasing means)
10 ... Push-back block 12 ... Coil spring (biasing means)
P · L ... Parting line A ... Molded product A ₁ ... General part A ₂ ... Side wall part A ₃ ... Terminal

Claims (3)

A pair of molds to be clamped and opened, and one of these molds is disposed at a position corresponding to the end of the molded product and is operated synchronously with an ejector pin when the molded product is released from the mold. And a push-up block that pushes up the terminal of the mold, and the push-up block is urged by a biasing means so that a predetermined amount can be projected from the parting line of the pair of molds when the pair of molds are opened. In
The other of the pair of molds is disposed so as to protrude and retract so as to face the push-up block, and when the pair of molds is clamped, the push-up block comes into contact with the party before the push-up block. An injection mold, in which a push-back block for pushing back to a position that is flush with the mold line is provided. The push-back block is, in the normal state is biased in a direction to protrude from the pair of mold parting line by a biasing means, the biasing of the biasing force P ₂ of the biasing means of the push-back block is the push block _2. The injection mold according to claim 1, wherein the injection mold is set to be larger than the urging force P ₁ of the urging means (P ₂ > P ₁ ).   The injection mold according to claim 1 or 2, wherein the contact surfaces of the push-up block and the push-back block are formed perpendicular to the mold release direction of the molded product.

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