RU2517508C1 - Mould for making reinforced rubber articles - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: proposed injection mould comprises gating chamber 1, runner plate 2, moulding unit 3 and mould 4 surrounding to accommodate check test pieces. Two internal semi-ring grooves 6 and two external semi-ring grooves 7 of smaller width and depth are made at runner plate 2 surface on the side of gating chamber 1. Cavities of said grooves are communicated with gating chamber 1 via vertical channels 8. Note here that cavities of internal grooves 6 are communicated via vertical channels 8 made inside runner plate 2 with moulding unit 3. Cavities of external grooves 6 are communicated via radial cut-outs 11 with cavities of grooves 6 and cavity of check test pieces mould 4.

EFFECT: high quality of moulded large-sized moving joints.

2 dwg

Description

The invention relates to the field of engineering, in particular to the technology of manufacturing movable joints in a mold, and can be used in the manufacture of reinforced shock absorbers and rubber-metal elements.

Known design molds for the manufacture of reinforced rubber products by injection molding (see, for example, patents of the Russian Federation No. 2131998, 2302944 and 2351472).

These molds contain a sprue (loading) chamber, a sprue plate and a forming block.

Also known is a mold for the manufacture of reinforced rubber products, including a sprue chamber, a sprue plate, a molding block and a mold covering it for witness samples (RF patent No. 2457943), the closest analogue.

The gating chamber and the gating plate are preheated and the elastomer when pressed, heated from their walls and at the same time acquiring the necessary plasticity, under pressure enters the forming block and the mold for witness samples.

Large-sized movable joints are made in this mold, while the presence of a mold for witness samples communicated by channels with the cavity of the forming block allows one to obtain elastomer witness samples whose properties correspond to the properties of elastomer layers pressed between the reinforcement elements of a rubber product.

However, the use of the known mold design for the manufacture of rubber products from modern elastomer grades, which require a higher heating temperature and a longer exposure time, reducing the elastomer viscosity and accelerating the molding time, the implementation in this mold of the most simple gating system made in the form vertical channels directly communicating the gate (loading) chamber with the cavity of the forming block, showed that in some cases in the manufactured rubber the level of residual internal stresses in the elastomer is unacceptably high.

It was found that large internal stresses in the elastomer are associated with the existing temperature difference across the thickness of the elastomer, due to its heating not homogeneous enough, before entering the forming block due to the insufficient heating time of the elastomer when it moves along the vertical gate channels.

These disadvantages lead to a decrease in the quality of manufacture of rubber products in the known design of the mold.

The technical task of this invention is to improve the quality of manufacture of rubber products by injection molding in a mold by making design changes aimed at creating optimal conditions for flow through the gate system of the elastomer softened during heating in the gate chamber to ensure its more uniform further heating before entering the molding block and into the mold for witness samples and thereby reduce the level of residual internal stresses in the pressed om in the product elastomer in samples-witnesses.

The technical result is achieved by the fact that in the mold for the manufacture of reinforced rubber products, including the sprue chamber, the sprue plate, the forming block and the mold for the witness specimens covering it, on the surface of the sprue plate from the side of the sprue chamber two internal semicircular grooves and two outer semicircular grooves, of smaller width and depth, the cavities of which are in communication with the gating chamber cavity with vertical channels made in its bottom, etc. This internal cavity communicated semicircular grooves formed in the sprue plate with vertical channels forming a cavity block, and a cavity external semicircular grooves communicated with radial slots semicircular internal cavities and grooves with the die cavity for witnesses samples.

The execution on the surface of the gating plate, heated during pressing, from the side of the also heated gating chamber separated by bridges of two internal and two external semicircular grooves connected with the cavity of the gating chamber, allows to increase the length of the gating system and increase the elastomer transit time through it, which contributes to its more uniform heating before entering the forming unit and the mold for witness samples and thereby reduces the level of residual internal stresses zhenie pressed into the elastomer.

Separate communication of each of the two internal and two external semicircular grooves with the gating chamber cavity with vertical channels made in its bottom allows to accelerate the process of filling the gating system with an elastomer.

The execution of the outer semicircular grooves of a smaller width and depth than the inner semicircular grooves is due to the smaller volume of elastomer filling the mold for witness specimens, as compared to the forming block.

The communication of the cavities of the internal semicircular grooves with the cavity of the forming block with vertical channels made in the sprue plate and the communication of the external semicircular grooves with the cavity of the mold for witness samples with radial slots allows you to speed up the process of filling the mold block and the mold for witness specimens with an elastomer.

The communication of the cavities of the external semicircular grooves with radial slots with the cavities of the internal semicircular grooves makes it possible to most rationally organize the flow of the softened elastomer through the gate system, which contributes to a more uniform heating of the elastomer before filling the forming block and the mold for witness samples.

Figure 1 shows the layout diagram of the mold.

Figure 2 shows the design of the sprue plate.

The mold for the manufacture of reinforced rubber products includes a gate chamber 1, a gate plate 2, a molding block 3, and mold cells 4 for witness specimens.

On the surface of the sprue plate 2 from the side of the sprue chamber 1, two internal semi-annular grooves 6 and two external semi-annular grooves 7 are separated from each other by jumpers 5.

The outer semi-ring grooves 7 are made of smaller width and depth than the inner semi-annular grooves 6.

In the bottom of the gate chamber 1, vertical channels 8 are made, communicating the cavities of the inner semicircular grooves 6 with the cavity of the gate chamber 1.

In the bottom of the gate chamber 1, vertical channels 9 are also made, communicating the cavities of the outer semicircular grooves 7 with the cavity of the gate chamber 1.

The cavities of the inner semicircular grooves 6 are communicated by vertical channels 10 made in the sprue plate with the cavity of the forming unit 3.

The cavities of the outer semicircular grooves 7 are communicated by radial slots 11 with the cavities of the inner semicircular 6 grooves and the radial slots 12 with the cavity of the form 4 for witness specimens.

The forming unit 2 is housed in a ferrule 13, which also contains cells 4 of the mold for witness samples, covering the forming unit 3.

Preparation of the mold for work is as follows.

The assembled mold 4 for witness test pieces and the molding block 3 with the fittings of the rubber product placed in it in the clip 13 are installed and the mold is finally assembled.

An elastomer (not shown) is placed in the gate chamber 1, the mold is heated, and the heated elastomer is pressed under pressure of the punch 14 through the gate system into the forming block 3 and mold cells 4 for the witness specimens.

The elastomer through the channels 8 and 9 fills, respectively, the cavity of the inner semicircular grooves 6 and the cavity of the outer semicircular grooves 7.

In this case, the elastomer flows through the slots 11, communicating the cavities of the grooves 6 and 7, the forming block 3 is filled through the channels 10 and the mold 4 for witness specimens is filled through the radial slots 12.

The flow mode of the softened elastomer through the gate system of the proposed design contributes to a more uniform heating of the elastomer and thereby reducing the level of residual internal stresses in the walls of the manufactured parts.

A higher heating temperature, which reduces the viscosity of the elastomer, speeds up the molding time.

After the molding process is completed, the mold is disassembled, the finished rubber product is removed from the molding unit 3, and witness samples are taken from the mold 4.

In the proposed design of the mold, it is possible to manufacture parts with low-strength or through fittings and parts with deep holes of small diameter, since the elastomer enters the forming block well preheated, in a plastic state and does not exert significant forces on the elements of the molding block of the mold and the fittings deformation.

Large internal stresses do not occur in the parts due to the smaller temperature difference across the thickness of the part walls.

In this mold, a number of large-sized movable joints are qualitatively manufactured at the enterprise.

Claims (1)

A mold for the manufacture of reinforced rubber products, including a sprue chamber, a sprue plate, a forming block and a mold covering it for witness samples, characterized in that on the surface of the sprue plate from the side of the sprue chamber two inner semicircular grooves are separated from each other and two external semicircular grooves, of smaller width and depth, the cavities of which are communicated with the gating chamber cavity by vertical channels made in its bottom, while the cavities are internal x semicircular grooves formed in the sprue communicated plate with vertical channels forming a cavity block, and a cavity external semicircular grooves communicated with radial slots semicircular internal cavities and grooves with the die cavity for witnesses samples.

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