DD259594A5 - Closing unit for a device for injection molding - Google Patents

Abstract

The invention relates to a closing unit for a device for injection molding of thermoplastic materials. It is characterized in that the end plate forms a linear motor together with the plunger, wherein in the face plate, the three-phase windings are arranged and the plunger is designed as a Laeuferschiene. Fig. 2

Description

GERMAN DEMOCRATIC REPUBLIC

(12) Exclusion Patent

Issued in accordance with § 17 paragraph 1 Patent Law

PATENT CODE DD (, η 259 594 A5

4 (51) B 29 C 45/66

OFFICE FOR INVENTION AND PATENT PROCESSES Published as filed by the Applicant

(21) AP B 29 C / 302 686 3 (31) A1267 / 86

(22) 12.05.87 (32) 13.05.86 (44) (33)

31.08.88 AT

(71) see (73)

(72) lleonhartsberger, Heinz; Wögerer, Alfred, AT

(73) Ludwig Engel KG, 4311 Schwertberg, AT

(74) International Patent Office Berlin, Wallstraße 23/24, 1020, DD

(54) Closing unit for an injection molding apparatus

(55) Closing unit, injection molding, linear motor, mold clamping pressure, electromagnet, face plate, thermoplastic material, plunger, three-phase winding, runner rail (57) The invention relates to a closing unit for a device for injection molding of thermoplastics. It is characterized in that the end plate forms a linear motor together with the plunger, wherein in the face plate, the three-phase windings are arranged and the plunger is designed as a rotor rail. Fig. 2

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ISSN 0433-6461

S sides

Claims (4)

1. Closing unit for a device for injection molding thermoplastics, with a fixed and a moving along Hofmen mold carrier plate, which each carry a mold half, and with a fixed end plate, in which extending in the direction of the machine axis, for opening and closing the mold and for the application of the mold closing pressure serving plunger is guided, characterized in that the end plate (7) together with the plunger (6) forms a linear motor, wherein in the face plate (7) the three-phase windings {13) are arranged and the plunger (6) Runner rail is formed. 2. Closing unit according to claim 1, characterized in that for increasing or generating the mold clamping pressure on the end plate (7) and / or one of the end plate facing part of the plunger (6) at least one electromagnet (1.2) is provided, which in stromdurchf Lichen Condition exerts a force directed to the form on the plunger (6). 3. Closing unit according to claim 2, characterized in that the one or more electromagnets {12) between a with the plunger (6) connected to the pressure plate (8) and the back of the end plate (7) are arranged. 4. Closing unit according to claim 3, characterized in that a screw connection (11) between plunger (6) and pressure plate (8) is provided, and the distance of the pressure plate (8) from the movable mold (5) by a geared motor (10). is changeable. For this 2 ropes drawings Field of application of the invention The invention relates to a closing unit for a device for injection molding thermoplastics, with a fixed and a movable along Holmen mold carrier plates, which each carry a mold half, and with a fixed end plate, in which extending in the direction of the machine axis, for opening and Closing the mold and for applying the mold clamping pressure serving plunger is guided. Characteristic of the known state of the art All currently used in practice closing units of injection molding equipment include hydraulic systems as an integral part. The cost of such systems are highly _r da allow slider and control valves nurgeringeToleranzen terms of manufacturing and assembly. Since the pressure of the hydraulic medium is generally very high (values of up to 300 bar), strict safety regulations must be observed, which in particular includes frequent inspection of the hose and piping Cuffs are subject to heavy wear, the use of hydraulic systems requires a lot of work. The system pressures that occur can be reduced if the hydraulic cylinders do not apply the mold clamping pressure to the mold directly but via the toggle lever. However, the advantage gained thereby is at least made up for by the need to make and maintain a number of other moving parts. Principally contemplated electromechanical closure systems are even more complicated and presently do not yet provide a solution to the transition in any phase in which the mold is to be moved relatively quickly to the injection phase, in which the mold is to be kept closed at high pressure. Apart from the high manufacturing and maintenance costs of current locking systems, these have the functional disadvantage that necessary for a necessary speed correction and at least for braking immediately before the meeting of the mold halves directional change of the drive is possible only with a delay, which reluctant to accept becomes. Object of the invention The aim of the invention is to avoid disadvantages of known devices. Explanation of the essence of the invention The invention has for its object to provide a closing unit, berwelcher in a very short time a significant change in the amount of acting forces or their polarity reversal is possible. This is achieved in that the end plate forms a linear motor together with the plunger, wherein the three-phase windings are arranged in the end plate and the plunger is designed as a rotor rail. ~ « Such a closing unit has the particular advantage that it works entirely without hydraulic elements and also has no moving drive parts for the plunger. This advantage can be enforced according to a preferred embodiment of the invention even if the force caused by the linear motor itself is insufficient to achieve the necessary closing pressure. In this case, at least one electromagnet is provided for increasing or generating the mold closing pressure on the end plate and / or a part of the pressure stamp facing the end plate, which exerts a force directed to the form in the current-carrying state on the plunger. The one or more electromagnets are arranged between a pressure plate connected to the pressure plate and the back of the face plate. It is also advantageous däß.eine screw connection between plunger and pressure plate is provided and the distance of the pressure plate of the movable mold by a geared motor is changeable. embodiments The invention will be explained in more detail in an embodiment with reference to the accompanying drawings. Show: Fig. 1: a first embodiment of the invention in a schematic, partially sectioned side view, Figure 2: the corresponding representation of a second embodiment. The injection molding device shown schematically consists of a fixed mold carrier plate 1, which cooperates with a movable mold carrier plate 5, which is longitudinally displaceable on spars 2. An injection unit 14 is provided, which brings the serving to form the molding mass in the mold cavity formed by the fixed mold half 3 and the movable mold half 4. In order to open the mold for the purpose of removing the finished molding, the movable mold carrier plate 5 by means of the plunger 6, which is mounted in the fixed end plate 7, in the drawing to the left and to close the mold in the reverse direction displaceable. This shift is now carried out by forming the cooperating parts of the plunger 6 and the end plate 7 as a double-sided linear motor, including both sides of the acting as a runner plunger 6 three-phase windings 13 are arranged. Details of the structure of the linear motor, which may also be referred to as a linear induction motor, are assumed to be known. The embodiment of Figure 2 differs from the simpler first embodiment in that in addition to the end of the plunger 6 at a connected to the plunger 6 Drucksterripel 8, an electromagnet 12 is provided. When this electromagnet 12 is activated, it pulls the pressure plate 8 against the end plate 7, whereby the mold halves are pressed increasingly firmly against each other until, by stretching the spars 2, the gap between the plates 7 and 8 is closed. On the one hand, the gap width should be variable in order to be able to limit the closing force to different values for a given mold height and, on the other hand, to compensate for different mold heights. To adjust the distance of the pressure plate 8 of the movable mold carrier plate 5 is a geared motor 10, which adjusts the screw connection between the pressure plate 8 and the plunger 6. The support of the linear motor according to the invention by electromagnets would alternatively also be possible in such a way that repelling electromagnets form a pressure pad, which is inserted in the closed mold in a conventional manner between the end of the plunger 6 and the front of the face plate 7.