DE102022102044A1 - Inclined slide and injection mold - Google Patents

Abstract

The invention relates to an inclined slide (1) for an injection mold (2), at least comprising a base shoe (3) and a rod (4) which can be mounted in the base shoe (3) and at whose head (5) at least one core (6) is arranged , wherein a central channel (7) is provided in the rod (4), which is surrounded by a jacket channel (8), the rod (4) preferably has a diameter (9) of at most 25 mm and an integral cooling or temperature control system .

Description

The invention relates to a plastic injection mold with a first and a second mold half which, when closed, delimit a mold cavity or cavity between them, the second mold half having at least one ejector or ejector plate with at least one ejector pin and at least one inclined slide.

In order to be able to inject protruding locking hooks, lugs or depressions, so-called inclined slides are used in injection molds, which release the locking lugs or hooks provided on the molded part after the end of the injection molding process by moving and pivoting the respective inclined slide. Within the injection mold, the inclined slides assume an inclined position that is dependent on the molded part and runs at a predetermined angle. The oblique slides extend over the entire area of the injection mold and are introduced with an end area in the sliding blocks of a headstock. After the end of the injection molding process, the inclined slides perform a pivoting movement due to the sliding blocks, so that the injection molded part is released.

In known plastic injection molds for the production of hollow or curved workpieces, the second mold half, referred to as the core, which gives the inner wall of the workpiece its shape, is usually fastened to a bridge-like, so-called substructure, which in turn is supported on a base or base plate which is to be connected to a clamping plate of the injection molding machine. The bridge-like substructure is used in order to obtain a movement space underneath for an ejector plate, which can be moved back and forth with a certain stroke by a linear drive supported on the bridge-like substructure and is connected to the ejectors and inclined slides via push rods. Since the push rods that move the inclined slides are arranged inclined with respect to the feed direction and are guided in a longitudinally displaceable manner in bores that extend obliquely through the bridge-like substructure, they displace the inclined slides sideways during the advance of the ejector plate, so that they protrude from projections or undercuts on the side wall of the work piece and it can finally be lifted off the core of the mold and ejected.

The problem here is that the production of the tool from a large number of moving parts is complicated and very expensive, and there is also the risk of the bridge-like substructure sagging and the relatively long push rods becoming deformed. In particular, there is a desire to accommodate the ejector arrangement or the oblique slide as compactly as possible in a small space. Another problem is that the oblique slides or the cores attached to them are exposed to high thermal (alternating) stresses, which may also result in undesirable deformation and/or impair the service life.

Proceeding from this, it is the object of the present invention to at least partially alleviate the problems described with reference to the prior art. In particular, solutions are to be shown with which the injection molding tool arrangement or subcomponents thereof can be simplified and/or the variable and permanent use of oblique slides can be improved. In addition, it should be made possible that a multiplicity of different injection molded products can be provided, ie a large variety of undercuts can be provided quickly and cost-effectively.

These objects are solved with the features of the independent claim. Advantageous developments are specified in the dependent claims. It should be pointed out that the features of the claims can be combined with one another in any technologically sensible manner and show further refinements of the invention. The description, in particular in connection with the figures, explains the invention and specifies further exemplary embodiments.

Contributing to this is an inclined slide for an injection molding tool, which comprises at least one base shoe and a rod which can be stored in the base shoe and at the head of which at least one core is arranged. Furthermore, a central channel is provided in the rod, which is surrounded by a jacket channel.

An injection molding machine can basically be divided into a plasticizing unit and a closing unit. The plasticizing unit is assigned a screw drive, for example, with the downstream screw conveyor being fed the desired amount of plastic and then being conveyed to the nozzle by means of the screw conveyor. The nozzle side of the injection molding tool arrangement is arranged in the area of the nozzle. On the opposite side, the ejector side of the injection molding tool arrangement is movably arranged, with the movement being carried out, for example, with a hydraulic cylinder. The injection molding tool arrangement on the nozzle side and the ejector side together form the injection molding tool.

In a broader sense, ejector elements for tool arrangements based on the principle of a plate structure for injection molding tools are also addressed here. Injection molds basically have roughly the same structure and can be divided into two halves, namely the so-called (first) nozzle side and the opposite (second) ejector side. The individual components of the mold are located in these two mold halves, namely the sprue systems and cooling or temperature control on the nozzle side, and the cores and cavity inserts, cooling or temperature control and ejector elements on the ejector side.

An inclined slide provided or set up for such an injection mold has a base shoe and a rod that can be stored in the base shoe. Such an inclined slide is sometimes also called an inclined ejector, inclined bolt with guide", undercut slide, etc. The base shoe can be designed, for example, in the manner of a guide bar, in which a foot or a (first) end of the rod is movably accommodated and/or mounted The base shoe can include a receptacle for the foot of the rod, which is in particular pivotable and/or movable (longitudinally) in the guide rail. It is possible for the base shoe to be mountable on a base plate of the injection mold, in particular the base plate on the ejector side The movement can be a (partial) rotation about an axis of rotation (e.g. up to 20 angular degrees) and/or a transverse movement (parallel to the base plate and/or inclined) in a predetermined direction relative to the base shoe or the tool arrangement. The base shoe can be self-lubricating be executed, for example with graphite.

It is possible that, in the mounted situation, the rod extends from the base shoe or the base plate through an ejector plate to the cavity of the tool arrangement. The rod therefore usually has a length along a central axis of at least 200 mm, for example in the range from 400 to 1000 mm [millimeters]. It is preferred that the rod only extends out of the base shoe on one side.

A (separate) core is or can be arranged at the head or at the (second) end of the rod opposite the base. The core is designed in such a way that it forms an undercut during injection molding. Depending on the type of undercut(s), the contour of the core can be relatively complex, possibly also with relatively filigree and/or massive sections. Due to the frequent contact with the hot injection molding material and/or the ambient conditions prevailing in the cavity, such cores can exhibit a significant tendency to wear. To counteract this, the inclined slide can be equipped with an integral cooling or temperature control system.

In particular for setting up such a cooling or temperature control system, the rod is designed with channels through which a suitable (liquid) cooling medium can be conducted. The duct system is designed in such a way that a central duct is provided, which is surrounded at least in sections by a jacket duct. This means in particular that the jacket channel extends at least partially in a circumferential direction of the central channel. It is possible that the jacket channel, viewed along the central axis of the rod, surrounds or "sheaths" the central channel to a different extent. In particular, it can be provided that the jacket channel surrounds the central channel less in the area or near the base shoe than at a greater distance from the base shoe or in the vicinity of the head. It is preferred that there is at least a partial section of the rod in which the jacket channel completely surrounds the central channel.

This configuration of the jacket channel and the central channel can serve to ensure that cooling medium is guided through both channels in countercurrent, with a good heat exchange being able to be achieved on account of the jacket.

As a precaution, it should be pointed out that the "central channel" does not necessarily or always have to encompass the central axis of the rod. Rather, this designation is only intended to clarify the (at least partially) internal position to the jacket channel. Furthermore, this is intended to express in particular that the two channels are not introduced into the rod in the manner of parallel bores.

It is preferred that the rod has a maximum diameter of 25 mm [millimeters]. This invention is particularly preferably used with very slender rods that are designed with a diameter of 20 mm or even less. It is precisely here that the proposed configurations of the channel system, the coolant connections, etc. are particularly efficient in alleviating the problems mentioned at the outset and which also occur intensively in the case of slender rods.

It is preferred that the central channel is arranged eccentrically to a central axis of the rod in at least one axial partial section of the rod. It is possible here for the central channel to have a central channel axis which is offset transversely to the rod. It is possible that the central canal also encompasses the central axis, but that is the case not mandatory. In particular, the eccentric position can be limited to an area adjacent to that of the base shoe and/or the coolant connections, so that a coaxial position is possible in the other areas. The eccentricity can be in the range of 0.5 - 2.0 mm [millimeters]. The eccentric design of the channels can be used in particular to use the same type of coolant connections, with the inlet and outlet being securely and precisely connected to the desired channel. If both coolant connections extend radially inwards into the rod to the same extent, they will only ever reach one of the two channels due to the eccentricity.

It is preferred that (two) coolant connections (each) towards the central channel or the jacket channel are or can be arranged laterally on the rod. It is very particularly preferred that a first coolant connection can be arranged radially on the outside or on the rod, which can be connected to the casing channel in a fluid-tight manner (eg inlet). It is further preferred that a second coolant connection can be arranged radially on the outside or on the rod, which can be connected to the central channel in a fluid-tight manner. The coolant connections are preferably diametrically opposite one another. The coolant connections are preferably constructed essentially identically. The coolant connections can include sockets on which a hose line can be arranged (in a fluid-tight manner).

The coolant connections are preferably arranged between the base shoe and the head of the rod, preferably in the lower section (ie close to the base shoe). The coolant connections can, for example, be positioned on the rod at a maximum distance of 100 mm from the base shoe, in particular only a maximum of 50 mm [millimeters].

It is preferred that the cooling or temperature control system only extends outside or above the base shoe (towards the head of the rod). In particular, the coolant connections and/or coolant channels should not (spatially) extend through the base shoe.

The coolant connections can be arranged on the outside of the rod via a ring adapter. A ring adapter can be designed in several parts, e.g. B. with two ring halves, which can be clamped onto the rod and / or in or over the entrance and exit ends of the channels of the rod. In the ring adapter, for example, radially running flow openings are formed, via which the inner channels can be connected to an outer hose guide. The ring adapter can ensure, particularly in the case of very slender designs of the rod, that there is an increase in diameter in the area of the coolant connections, so that standardized components can nevertheless be used or large flow cross sections can be realized.

The jacket channel can open into (at least) one cavity of the core, which extends up to the central channel. In particular, the cavity provides a flow deflection for coolant, which on the one hand brings about intensive contact between the cold coolant (ascending in the jacket channel) and the core and complete forwarding or dissipation of the (warm) coolant via the central channel. The cavity can be designed in the form of a bubble and/or in the manner of a channel system in the core.

The core can be designed so that it can be plugged onto the rod. In particular, the rod can have a head surface at the end, up to which both channels extend. The core can have a rod receptacle into which the head of the rod can be inserted and sealed in a fluid-tight manner. It is possible that the rod holder connects to the cavity of the core. In the assembled situation, the head can (entirely) accommodate and seal the (upper) end or head of the rod. For this purpose, the core can be fastened to the outside of the rod.

It is particularly preferred that the core can be aligned with a wedge connection at the head of the rod. In particular, the core and rod can be aligned along the central axis, so that z. B. a fluid-tight connection and / or exact alignment of the core to the cavity can be adjusted. A wedge connection can be set up for this purpose, with an adjustment of a wedge lock resulting in a displacement of the core relative and axially to the rod.

According to a further aspect, an injection mold is proposed which comprises at least one oblique slide of the type presented here. With regard to the technical details of such an injection mold, full reference is made to the introduction and/or the explanations regarding the function or type of inclined slide.

The use of indefinite articles ("a", "an", "an" and "an"), particularly in the claims and the description reflecting them, should be understood as such and not as a numeral. Correspondingly introduced terms or components are to be understood in such a way that they are present at least once and in particular can also be present several times. If a component can occur more than once ("at least one"), the description of one of these components can apply to all or part of the Majority of these components apply equally, but this is not mandatory.

As a precaution, it should be noted that the numerals used here (“first”, “second”, ...) primarily (only) serve to distinguish between several similar objects, sizes or processes, i.e. in particular no dependency and/or sequence of these objects, sizes or make processes mandatory for each other. Should a dependency and/or order be necessary, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described embodiment.

• 1: eine Darstellung der Funktionsweise eines Schrägschiebers;
• 2: eine perspektivische Darstellung eines Schrägschiebers im Eingriff mit einem Werkstück;
• 3: ein Detail eines Schrägschiebers im Bereich des Basisschuhs;
• 4: eine Seitenansicht einer Ausführungsvariante eines Schrägschiebers;
• 5: ein Detail eines Schrägschiebers im Bereich der Kühlmittelanschlüsse;
• 6: ein Detail eines Schrägschiebers im Bereich des Kopfes;
• 7: eine Veranschaulichung der ausgerichteten Befestigung des Kerns.

The invention and the technical environment are explained in more detail below with reference to figures. It should be pointed out that the figures show embodiment variants to which the invention should not be restricted. Identical components are regularly provided with the same reference symbols, so that the corresponding explanations with regard to other figures can be referred to. Individual features from the figures, unless otherwise indicated, can be extracted and combined with other features from other figures or the description and used to characterize the invention. They show schematically:

• 1 : a representation of the functioning of a slanted slide;
• 2 : a perspective view of a slanted slide in engagement with a workpiece;
• 3 : a detail of an inclined slider in the area of the base shoe;
• 4 : a side view of a variant of an inclined slide;
• 5 : a detail of an inclined slide in the area of the coolant connections;
• 6 : a detail of a slanting slide in the area of the head;
• 7 : an illustration of the aligned attachment of the core.

1 discloses an embodiment of an injection mold 2 for producing hollow or curved (plastic) workpieces 19. The injection mold 2 comprises a first mold half 16 and a second mold half 17, the inner walls or cavity 18 of which gives the workpiece 19 its shape. The workpiece 19 has undercuts here on the underside or on the second mold half 17, for the demolding of which two oblique slides 1 are provided. The inclined slides 1 stand in different orientations by means of base shoes 3 on a common base plate 20. From there and through the second tool half 17 (or the ejector plate 21), a rod 4 of the inclined slide 1 extends, at the head of which it penetrates into the undercuts engaging core 6 is provided. With (a) is in 1 illustrates the situation before or during which plastic is injected into the cavity 18 of the closed injection mold 2. When this process is completed, the injection molding tool 2 is opened (see situation (b)), so that a surface of the workpiece 19 is now exposed. Then the workpiece 19 z. B. lifted out of the cavity 18 by a movement of the ejector pins (not shown) of the ejector plate 21 and/or the inclined slide 1 . In this case, the oblique slides 1 can be moved relative to the workpiece (independently or with a predetermined movement path) 19, in particular rotated and/or moved. The cores 6 are removed from the undercuts of the workpiece 19 so that the workpiece 19 can be removed as a whole from the injection mold 2 (see situation (c)).

2 illustrates a perspective view (from below) of an inclined slide 1 with a rod 4, at the opposite ends of which are arranged the base shoe 3 on the one hand and the core 6 engaging in the undercut part 22 of the workpiece 19 on the other. The oblique slide 1 is designed with an integral cooling or temperature control system and therefore has coolant connections 11, 12 suitable for hoses above the base shoe 3.

The 3 shows a cross section through a foot of an inclined slide, which is otherwise shown in perspective. The cross section is in a section of the rod 4 in which the coolant connections 11, 12 are located.

A first coolant connection 11 (coming from the right) is shown in cross section, via which (cold) coolant, for example water, can be supplied to the oblique slide. The first coolant connection 11 opens out via a ring adapter 13 attached to the outside of a rod 4 in the jacket channel 8 in the rod 4. From there, the coolant is guided along the jacket channel 8 (upwards) to the core 6 (not shown), where it is reversed and flows again via the central channel 7 towards the cross-section shown. From there, the (heated) coolant flows again via the ring adapter 13 into a second coolant connection 12 diametrically opposite the first coolant connection 11, from which it can be guided away.

Below the cross section is further illustrated that the rod 4 in a base shoe 3 is movably mounted, which can be screwed onto the base plate, for example. The rotational or translational movements of the rod 4 relative to the base shoe 3 are indicated with arrows.

4 shows a side view of an inclined slide 1. The inclined slide 1 comprises a base shoe 3 indicated here and a rod 4 which can be mounted in the base shoe 3 and on the head 5 of which a core 6 is arranged. Furthermore, a central channel 7 is provided in the rod 4, which is surrounded by a jacket channel 8, so that a countercurrent principle (see the direction of flow indicated by arrows) can be implemented when flowing through the rod 4. For this purpose, (all) coolant connections 11 , 12 are positioned close to the base shoe 3 , for example with a predetermined small distance 28 .

5 shows another embodiment of a connection option for coolant connections 11, 12 to a rod 4 of inclined slide 1. In the middle of the figure it is shown that in this cross section the central channel 7 is arranged eccentrically to a central axis 10 of the rod 4, i.e. the central channel axis is not coaxial to the central axis 10 of the rod 4 is positioned. At the same time, it is provided that the central channel 7 is surrounded by the jacket channel 8 (in part, for example in an approximately semicircular manner).

This figure also shows that the lateral first coolant connection 11 extends towards the jacket channel 8 and the lateral second coolant connection 12 towards the central channel 7 .

A two-part ring adapter 13 (with a first ring half 23 and a second ring half 24) is attached to the outside of the rod 4 and by means of clamping means, which provides separate access to the central channel 7 and the jacket channel 8, if necessary by means of integrated spacer sleeves. The ring adapter 13 can be designed in the manner of a clamp. The ring adapter 13 allows relatively large coolant connections 11, 12 to be attached to a very slim rod 4 in a fluid-tight manner.

6 and 7 show details of a connection of the core 6 to the head 5 of the rod 4. In this section, the rod 4 has a central channel 7 which is arranged eccentrically to the central axis 10 of the rod 4, this being partially surrounded by the jacket channel 8. The jacket channel 8 extends to a cavity 14 of the core 6 where the inflowing (cold) coolant is distributed and/or deflected in the core 6 so that it can flow into the central channel 7 and thus out of the core 6 .

Here, the core 6 is pushed onto the rod 4 in the area of the head 5 and aligned by means of a wedge connection 15 . For this purpose, the core 6 has a rod receptacle which can accommodate the entire diameter 9 of the rod 4 so that its head face 27 is accommodated there. For this purpose, the wedge connection 15 can be designed with a wedge bolt 26 which, when the clamping means 29 is tightened, slides along a bevel 25 of the core 6 and thus axially aligns the core 6 with the rod so that a fluid-tight connection is established.

Obviously, with this invention, the problems outlined with reference to the prior art can be at least partially solved. In particular, solutions were shown with which the injection mold arrangement or subcomponents thereof can be simplified and/or the variable and long-term use of oblique slides can be improved. In addition, it was made possible that a large number of different injection molded products can be provided, i.e. a large variety of undercuts is available quickly and inexpensively.

Reference List

1

inclined slide

2

injection mold

3

base shoe

4

pole

5

Head

6

core

7

central channel

8th

jacket channel

9

diameter

10

central axis

11

first coolant connection

12

second coolant connection

13

ring adapter

14

cavity

15

wedge connection

16

first tool half

17

second tool half

18

cavity

19

workpiece

20

base plate

21

ejector plate

22

undercut part

23

first ring half

24

second ring half

25

oblique

26

wedge bar

27

head face

28

Distance

29

clamping devices

Claims (9)

Inclined slide (1) for an injection molding tool (2), at least comprising a base shoe (3) and a rod (4) that can be mounted in the base shoe (3) and at whose head (5) at least one core (6) is arranged, wherein in the Rod (4) a central channel (7) is provided, which is surrounded by a jacket channel (8). Inclined slide (1) after claim 1 , wherein the rod (4) has a maximum diameter (9) of 25 mm. Inclined slide (1) according to one of the preceding claims, wherein the central channel (7) is arranged eccentrically to a central axis (10) of the rod (4). Inclined slide (1) according to one of the preceding claims, in which coolant connections (11, 12) are arranged laterally on the rod (4) towards the central channel (7) or the jacket channel (8). Inclined slide (1) according to the preceding claim, in which the coolant connections (11, 12) can be arranged on the outside of the rod (4) via a ring adapter (13). Inclined slide (1) according to one of the preceding claims, in which the casing channel (8) opens into a cavity (14) in the core (6) which extends as far as the central channel (7). Inclined slide (1) according to one of the preceding claims, in which the core (6) can be slipped onto the rod (4). Oblique slide (1) according to the preceding claim, in which the core (6) can be aligned with a key connection (15) on the head (5) of the rod (4). Injection mold (2) comprising at least one inclined slide (1) according to one of the preceding claims.

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