DEVICE AND METHOD FOR PRODUCING PLASTICS COMPONENTS

Abstract

A device that produces component from a plastics material by injection moulding includes two mould halves. The two mould halves can be pressed together releasably and, in the pressed-together state, form at least one gate region and at least one common cavity for moulding the plastics material. The gate region is fluidically connected to the cavity for the purpose of introducing the plastics material into the cavity. At least one deflecting element is provided, which is arranged movably in the gate region and is formed to prevent or at least to impede flowing of the plastics material through a partial region of the gate region, the location of which results from the respective position of the deflecting element, in a manner depending on the respective position of the deflecting element

Claims

1-21. (canceled)

22. A device for producing a component from a plastics material by injection moulding, the device comprising: two mould halves configured to be pressed together releasably and, in the pressed-together state, form at least one gate region and at least one common cavity for moulding the plastics material, wherein the gate region is fluidically connected to the cavity to introduce the plastics material into said cavity, wherein at least one deflecting element is arranged movably in the gate region, wherein the deflecting element is formed to prevent or at least to impede flowing of the plastics material through a partial region of the gate region, the location of which results from the respective position (of the deflecting element, in a manner depending on the respective position of said deflecting element.

23. The device according to claim 22, wherein the deflecting element is fastened to a shaft.

24. The device according to claim 22, wherein the deflecting element is formed in the shape of a quarter of a circle, a semicircle, or three-quarters of a circle.

25. The device according to claim 22, wherein the form of the deflecting element is adapted to the form of the gate region and at least partially fills said gate region.

26. The device according to claim 23, wherein the deflecting element is fastened releasably to the shaft by at least one fastening means.

27. The device according to claim 26, wherein the deflecting element comprises the at least one fastening means, or the shaft comprises the at least one fastening means and the deflecting element is fastened to the fastening means.

28. The device according to claim 22, wherein the gate region is formed in the shape of a fan, disc and/or plate, or film.

29. The device according to claim 22, wherein the deflecting element has at least one deflecting face, which brings about a movement of the deflecting element by contact with the inflowing plastics material.

30. The device according to claim 22, wherein the deflecting element is configured to be moved by at least one tool slide of the device or by a hydraulic motor or by an electric motor.

31. The device according to claim 22, wherein at least one sensor is arranged at the cavity, at the gate region, at the deflecting element, or at an element of the device that is connected to the deflecting element, the sensor is configured to detect a parameter of the injection-moulding process, and the sensor is configured to provide control signals for controlling the movement of the deflecting element depending on the parameter data detected.

32. The device according to claim 22, wherein the device is configured to be used in the production of cylinder housings.

33. A deflecting element for at least partial insertion into a gate region of an injection-moulding tool, wherein the deflecting element is movable and is formed to prevent or at least to impede flowing of the plastics material through a partial region of the gate region, the location of which results from the respective position of the deflecting element.

34. The deflecting element according to claim 33, wherein the deflecting element is fastened to a shaft.

35. The deflecting element according to claim 33, wherein the deflecting element is formed in the shape of a quarter of a circle, a semicircle, or three-quarters of a circle.

36. The deflecting element according to claim 33, wherein a form of the deflecting element is adapted to the form of the gate region.

37. The deflecting element according to claim 33, further comprising at least one fastening means.

38. A method for producing a component by injection moulding, comprising: pressing two mould halves together releasably, wherein, in the pressed-together state, the two mould halves form at least one gate region and at least one common cavity for moulding the plastics material; liquefying a plastics material by heating and subsequently introducing the plastics material into the cavity via the gate region, wherein, during the introduction of the plastics material into the cavity, at least one deflecting element is moved in the gate region, wherein the deflecting element prevents or at least impedes flowing of the plastics material through a partial region of the gate region, the location of which results from the respective position of the deflecting element, in a manner depending on the respective position of said deflecting element.

39. The method according to claim 38, wherein the deflecting element is moved on a circular path in the gate region.

40. The method according to claim 39, wherein the deflecting element passes through the circular path at least once during the introduction of the plastics material.

41. The method according to claim 38, wherein the speed at which the deflecting element is moved depends on the duration of the introduction of the plastics material.

42. A cylinder housing that is produced by the method according to claim 38.

Description

[0033] Further advantages and features of the invention become apparent from the following description with regard to the exemplary embodiments illustrated in the drawings, in which:

[0034] FIG. 1: shows a longitudinal section through a part of an exemplary embodiment of a device according to the invention,

[0035] FIG. 2: a) shows a perspective view of a deflecting element according to the invention which is fastened to a shaft,

b) shows a perspective view of different exemplary embodiments of the deflecting element according to the invention,

[0036] FIG. 3: shows a plan view of the “ejector side” of a finished component with a schematic illustration of different positions of the deflecting element according to the invention, and

[0037] FIG. 4: shows a perspective view of a finished component with a weld line.

[0038] For the purpose of simplification, identical elements are denoted by identical reference signs in the figures even in the case of different embodiments.

[0039] FIG. 1 shows a longitudinal section through a part of an exemplary embodiment of a device 1 for producing a plastics component by means of injection moulding. The device 1, which can be in particular a part of an injection-moulding tool, comprises a first mould half 2 (“nozzle side”, illustrated only partially here) and a second mould half 3 (“ejector side”, likewise illustrated only partially here) which form the injection-moulding tool for moulding the plastics material. The two mould halves 2, 3 can be brought into contact by axially displacing one of the two mould halves 2, 3 or both mould halves 2, 3, the injection-moulding tool being closed by pressing together the two mould halves 2, 3. In the closed state, illustrated here, the two pressed-together mould halves 2, 3 enclose a gate region 4 and a common cavity 5, in which the component to be produced is formed. In the embodiment illustrated here, the gate system comprises an injection channel 6 for injecting the plastics material into the cavity 5, which is configured as a hot-runner variant. The injection unit of the injection-moulding machine presses a molten, fluid plastics material into the injection channel 6, which can be heated by a temperature controlling device 7 for controlling the temperature of the plastics material located in the injection channel 6. The fluid plastics material is injected out of the injection channel 6 into the gate region 4 via a nozzle 8, there firstly strikes a plate- and/or fan-shaped element 9 and then flows over said element into the cavity 5. On the “nozzle side”, the fan-shaped element 9 forms an injection face and thus in practical terms constitutes a fan gate. On the “ejector side”, the fan-shaped element 9 comprises a central extension 10 which can be pushed in a form-fitting manner into a corresponding depression in the second mould half 3. The second mould half 3 comprises a central cylinder 11 (see FIG. 2) which is surrounded by a free space 12. The second mould half 3 also has an ejector device (the ejectors of the ejector device are not visible here, since they are shortened in this embodiment), by means of which the moulded and hardened finished component can be ejected out of the injection-moulding tool at the end of the injection-moulding operation.

[0040] FIG. 2 a) shows a perspective view of an exemplary deflecting element 15 according to the invention, which is fastened to a shaft 16. The deflecting element 15 is formed in the shape of three-quarters of a circle and can thus cover 75% (270° of 360°) of a circular portion, for example of a fan-shaped gate region.

[0041] FIG. 2 b) shows the deflecting element 15 according to the invention without a shaft (at the top) and two further exemplary embodiments of the deflecting element 17, 18 according to the invention. The deflecting element 17 (in the middle) is formed in the shape of a semicircle, while the deflecting element 18 (at the bottom) is formed in the shape of a quarter of a circle. The deflecting element 17 can thus cover 50% (180° of 360°) and the deflecting element 18 can thus cover 25% (90° of 360°) of a circular portion, for example of a fan-shaped gate region.

[0042] FIG. 3 shows that side (“ejector side”) of a finished component 20 which faces the second mould half 3 according to FIG. 1, the fan-shaped element 9, which forms the fan gate, and, schematically, different positions of a deflecting element 21 according to the invention additionally also being reproduced in this illustration. The embodiment illustrated here is a test variant, in which, after ejecting the component 20 out of the injection-moulding tool, the fan-shaped element 9 remains initially in the component 20, and therefore said test variant still has to be removed therefrom for further use. The deflecting element 21 is positioned within the gate region 4 of the device 1 according to FIG. 1 initially in such a way that it prevents flowing of the molten plastics material into a first region of the cavity 5, which is located downstream of the first portion 22 of the gate region 4 that is covered by the deflecting element 21 (position 21.1). The deflecting element 21 is then rotated counterclockwise within the gate region 4 of the device 1 according to FIG. 1 in such a way that it prevents flowing of the molten plastics material into a second region of the cavity 5, which is located downstream of the second portion 23 of the gate region 4 that is covered by the deflecting element 21 (position 21.2). Since the deflecting element 21, on account of its different positions in a sequence offset in time, blocks and/or delays flowing of the plastics material into different regions of the circular portion 19 of the gate region 4, the form and/or the progression of the weld line which forms in the region in which the flow fronts of the plastics material meet can be changed in a targeted manner by moving the deflecting element 21 in the gate region. Thus, for example, during the production of cylindrical components, a curved weld line can be created by rotating the deflecting element in the fan gate (see FIG. 4).

[0043] The component 20 is a cylinder housing for a concentric central actuator (central release mechanism). The component 20 comprises an annular base body 24, onto which are moulded a pressure connector 25 and three flanges 26, which are provided to fasten the cylinder housing to for example a transmission housing of a motor vehicle. The pressure connector 25 is formed by means of a mould core which is placed into the injection-moulding tool and around which the plastic flows during the injection-moulding operation. The pressure connector 25 is fluidically connected to the annular working space of the cylinder formed by the base body 20, and therefore a pressure medium can be admitted to the cylinder.

[0044] FIG. 4 shows that side (“nozzle side”) of a finished component 20 which faces the first mould half 2 according to FIG. 1, which component has been produced by the method according to the invention and by means of a device according to the invention having a movable deflecting element. The weld line 27 is no longer a straight line which extends along the longitudinal axis of the cylindrical component 20, but rather runs in a curved manner, since the deflecting element has been moved within the gate region during the injecting operation. FIG. 3 thus shows that the form and/or the progression of the weld line in the finished injection-moulded components can be influenced in a targeted manner by moving a deflecting element within the gate region, without the form and surface structure of the cavity of the injection-moulding tool having to be changed. For example, a curved or spiral-shaped weld line can be created by means of the method according to the invention. In this way, the mechanical strength of injection-moulded components can be significantly increased.

LIST OF REFERENCE SIGNS

[0045] 1 Device [0046] 2 Mould half [0047] 3 Mould half [0048] 4 Gate region [0049] 5 Cavity [0050] 6 Injection channel [0051] 7 Temperature controlling device [0052] 8 Nozzle [0053] 9 Fan-shaped element [0054] 10 Extension [0055] 11 Central cylinder [0056] 12 Free space [0057] 13 [0058] 14 [0059] 15 Deflecting element [0060] 16 Shaft [0061] 17 Deflecting element [0062] 18 Deflecting element [0063] 19 Circular portion [0064] 20 Component [0065] 21 Deflecting element [0066] 22 First portion [0067] 23 Second portion [0068] 24 Base body [0069] 25 Pressure connector [0070] 26 Flange [0071] 27 Weld line