• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Injection unit (1) for a shaping machine (2), in particular injection molding machine, with an injection piston (3), a drive device (4) for moving the injection piston (3) and a force accumulator, wherein the energy accumulator drives the drive device (4) with the injection piston (3 ) connects.
    公开号:AT515479A1
    申请号:T143/2014
    申请日:2014-02-28
    公开日:2015-09-15
    发明作者:Franz Ing Dirneder；Gottfried Dipl Ing Hager；Martin Ing Gusenbauer；Hannes Dipl Ing Bernhard
    申请人:Engel Austria Gmbh；
    IPC主号:
    专利说明:

    The invention relates to an injection unit for a shaping machine, in particular injection molding machine, with an injection piston, a drive device for moving the injection piston and a force accumulator. In addition, the invention relates to a shaping machine with at least one such injection unit.
    For injection molding machines for forming machines, there have been many further developments for years. It is particularly important here that the molded parts produced are manufactured more and more accurately and with ever better quality and reproducibility. An essential area that has to be taken into account is the entire injection area or injection channel and, in particular, the injection pressure, which has a significant effect on the quality of the molded part. In recent years, in addition to pure plastic, additives such as metals, glass fibers, etc. are increasingly being used in shaping and injection molding processes. Especially in metal injection molding and generally with high levels of additives, the compressibility of the injected material is low or less than with pure plastic injection molding. With process-related high injection speeds and just this low compressibility of the material to be processed, the inertia of the involved drive elements can lead to relatively long braking distances and thus cause impermissibly high internal mold pressures. As a result, the quality of the molded part is impaired and the entire components of the injection unit are (too) highly stressed.
    The object of the present invention is therefore to provide an improved injection unit. In particular, the disadvantages known from the prior art should be eliminated. Above all, too high internal mold pressures should be prevented.
    This is achieved by an injection unit having the features of claim 1. Accordingly, it is provided that the energy accumulator connects the drive device with the Einspritzkoiben. The energy storage thus forms a kind of overload protection. In other words, by the energy storage between Einspritzkoiben and
    Drive device, the axial stiffness of the linearly moving components are greatly reduced from a certain level of force and thus the mechanics are protected from overloading. That is, the injection piston can compress axially, since it is connected via the energy storage directly to the, preferably at least translationally movable, drive device.
    From the prior art, energy accumulators or springs in the region of the injection piston have hitherto only been known in the case of non-return valves, with which, however, a completely different purpose is fulfilled, namely to prevent the injection material from flowing back into the region between injection piston and injection cylinder. Examples are given in US Pat. No. 5,441,400, DE 1 201 039, DE 25 22 616, EP 0 323 556 A2, EP 0 541 048 A1 and US Pat. No. 5,044,926. All of these non-return valves have energy accumulators in the form of spring devices in order to block the return flow of the injection material from a certain injection pressure. But with these devices can not be prevented that there is too much pressure in the cavity of a mold. Rather, these Rückströmsperren form a fixed or fixed part of the injection piston, especially at high pressures. In contrast, in the present invention, the energy storage does not work between injection piston and injection cylinder as in a backflow, but directly between injection piston and drive device.
    In principle, the energy accumulator can be arranged only in the injection piston, that is, for example, connect a front part of the injection piston with a rear part of the injection piston. From the claim wording is also included this variant, since then it is still the case that the energy storage connects the front part of the injection piston - with the interposition of the rear part - with the drive device. It is important that the energy storage - a damping acting - is part of the drive train (from the drive device to the tip of the injection plunger). The energy accumulator must at least be arranged so that the piston tip is movable relative to the drive device and thus yielding through it.
    As known per se, the injection unit has an injection cylinder in which the injection piston is mounted at least translationally movable. It may also be provided that the injection piston is designed as an injection screw, wherein the injection screw of the drive device is translationally and rotatably drivable.
    Furthermore, the injection unit may have a control or regulation unit. This makes it possible, above all, for injection material to be injectable into the cavity of a molding tool of the molding machines by means of the injection piston with a standard injection pressure which can be fixed via the control unit. The control unit can be operated by an operator via an operating unit together with the screen.
    In principle, the energy accumulator can be designed in the form of rubber-like buffer elements. It can also be designed as a damping piston or hydraulic cylinder. Preferably, however, it is provided that the energy accumulator is designed as a spring device.
    Particularly important in the present invention is that the spring device does not interfere with a "normal" injection process. That is, the spring device is so stiff that it forms a solid, inelastic component of the drive train from the drive device to the tip of the injection piston. It is preferably provided that the spring device has a rigidity which essentially corresponds to a counterforce acting on the injection piston at standard injection pressure from the injection material. The stiffness describes the resistance of a body to elastic deformation by a force or a torque. This resistance comes from injecting the injection material, which can not be further compressed in the closed cavity. In other words, the bias of the spring device corresponds to the standard injection pressure. This standard injection pressure can be, for example, about 2000 bar, but can vary greatly depending on the application.
    In order to prevent excessively high cavity or mold internal pressures, it is particularly preferred that, at an elevated injection pressure above the standard injection pressure, the injection piston be movable relative to the stiffness of the spring device and under elastic deformation of the spring device relative to the drive device. In other words, the drive train movement is damped by the elasticity of the spring device, whereby the internal mold pressure is not too high.
    It is particularly preferred that this spring device has a plurality of springs, preferably helical springs, preferably arranged regularly around an injection unit longitudinal axis.
    In order to allow a precise damping movement and also to prevent an inclined position of these springs, it is preferably provided that the relative movement between the drive device and the injection piston is guided via at least one guide element. It is particularly preferably provided that each guide element is surrounded by a spring of the spring device. In other words, a guide element is passed through each spring.
    Protection is also sought for a molding machine, in particular injection molding machine, with at least one injection unit according to the invention.
    Further details and advantages of the present invention will be explained in more detail with reference to the description of the figures and the reference to the exemplary embodiments presented below. Show:
    1 shows schematically a forming machine with an injection unit and a mold,
    2 to 5, the injection unit with the injection piston and the spring device in different positions,
    6 and 7 details of the connection between the drive device and injection piston and
    Fig. 8 is a pressure-displacement diagram with and without spring device in comparison.
    In Fig. 1, a shaping machine 2 is shown schematically, which has an injection unit 1 and a mold 10 as essential components. In addition, such a shaping machine 2 normally also comprises platen plates and a toggle mechanism, not yet shown. In order to produce a molded part or injection-molded part, starting material (for example plastic granulate, metal or ceramic powder, additional fillers such as glass fibers, additional liquids or optionally also mixtures thereof) is first introduced into an intermediate space between injection cylinder 6 and injection piston 3 via a feed hopper 21.
    When the injection piston 3 is formed as an injection screw 11, by rotating the injection screw 11, the starting material is melted. The rotational movement is initiated by the drive device 4 in the injection screw 11. After melting, the injection takes place, for which the injection screw 11 is moved in a piston-like or translational manner by the drive device 4, whereby the molten injection material 8 accumulated in front of the tip of the injection screw 11 is injected into the cavity 9 via the injection channel 22. This cavity 9 is formed between the mold halves 19 and 20 of the mold 10. The injection process can be controlled manually by an operator. Preferably, however, the entire injection process via an operating unit and a control or regulating unit 7 is adjustable. Above all, the standard injection pressure Pstand can be set via this control or regulating unit 7. The set standard injection pressure Pstand should normally correspond to a cavity pressure actually given in the cavity 9.
    However, it can now happen that due to process-related high injection speeds and thus long braking distances or due to low compressibility of the material to be processed too high internal mold pressures are caused. In order to prevent this, an energy accumulator in the form of a spring device 5 is arranged between injection piston 3 and drive device 4. This connects the injection piston 3 with the drive device 4. The spring device 5 forms a damper or buffer to compensate for high internal mold pressures. The injection piston 3 is thus resiliently mounted. For example, reference is made to the following description of FIGS. 2 to 5.
    In Fig. 2, the injection material 8 is already melted in the front region of the injection unit 1. The injection process begins by the injection screw 11 is moved to the left via the drive device 4. The still low injection pressure P- is below the standard injection pressure Pstand. The spring device 5 has such a high rigidity F that it forms a fixed, immovable part of the drive train at this injection pressure.
    This is still the case when, according to FIG. 3, the injection screw 11 is in the foremost position and the injection unit 1 has reached the standard injection pressure Pstand. In this case, the counterforce G acting on the injection piston 3 from the injection material 8 is not higher than the stiffness F of the spring device 5.
    In general, starting from this position according to FIG. 3, the injection piston 3 can then move further in the direction of the cavity 9, whereby, for example, a holding pressure is exerted. In this case, it can occur that the internal cavity pressure in the cavity 9 is too high, which acts on the injection piston 3 as an opposing force G via the injection material 8. By this over the standard injection pressure Pstand increased injection pressure P + of the injection piston 3 is moved under elastic deformation of the spring device 5 relative to the drive device 4 (see Fig. 4). As a result, an undesired overload is actively counteracted by damping the drive train.
    As soon as the in-mold pressure has decreased again or as soon as the movement of the driven mass is stopped, the spring device 5 can again disengage (see FIG. 5) and again forms a "firm" or stiff part of the drive train. Thus, the spring device 5 on the one hand has a damping effect and transmits torque on the other hand.
    6 and 7 show different views of a concrete embodiment of an injection unit 1 with spring device 5. On the drive side, the injection unit 1 and its drive device 4, a drive motor 14, a driven by the drive motor 14 drive rod 15 and connected to the drive rod 15 drive plate 16. On the piston side, the injection unit 1 at the end facing away from the cavity 9 of the injection piston 3 has a piston skirt 17. In between, the spring device 5 is arranged in the form of a spring assembly with a plurality of - in particular ten - springs 13, the springs 13 are arranged regularly around the injection unit longitudinal axis L and abut on the one hand to the drive plate 16 and on the other hand on the piston shaft 17. In the piston shaft 17 ten rod-shaped guide elements 12 are fixed. On the end remote from the piston skirt 17, these guide elements 12 are movably guided in recesses 18 of the drive plate 16. Around the ten guide elements 12 around a spring 13 of the spring device 5 is arranged in each case. The drive plate 16 simultaneously forms a kind of clamping sleeve, with which the springs 13 are biased. That is, the guide elements 12 are at the same time screw elements which are screwed to the piston shaft 17 and via which the drive plate 16 is connected to the piston shaft 17. The drive plate 16 is longitudinally displaceable relative to the screw elements or to the guide elements 12. The further these screw elements are screwed into the piston shaft 17, the greater the bias of the springs 13 and thus the permissible standard injection pressure Pstand · With this design, a stable power transmission in the drive train with translational movement, rotational movement and damping on the spring device. 5 guaranteed.
    Fig. 8 shows in a diagram opposite an injection unit 1 without spring device 5 and an injection unit 1 with spring device 5. The horizontal axis shows the way that an injection piston 3 and the drive rod 15 travels during injection. The vertical axis shows the injection pressure P or P +, which prevails during the injection in the cavity 9 or in the injection channel 22. At the beginning of the injection - that is, during the filling phase - the injection piston 3 moves continuously forward, wherein the injection pressure P increases only slightly during this filling phase. Once the cavity 9 is filled, the rises
    Injection pressure P strongly due to the further movement of the injection piston 3 until the standard injection pressure Pstand is reached. If no spring device 5 is arranged between injection piston 3 and drive device 4, an undesirably high injection pressure P + can be achieved (see dashed pressure peak). However, if an inventive energy store (spring device 5) is used, this pressure peak is averted and the forward movement actually carried out by the drive device 4 is not entirely transferred to the injection piston 3 but a relative movement between the drive device 4 and the injection piston 3 is carried out in accordance with the travel. The standard injection pressure Pstand essentially corresponds to the pretension or stiffness F of the spring device 5.
    Innsbruck, on the 27th of February 2014
    权利要求:
    Claims (14)
    [1]
    1. Injection unit (1) for a molding machine (2), in particular injection molding machine, with - an injection piston (3), - a drive device (4) for moving the injection piston (3) and - an energy storage device, characterized in that the energy storage the Drive device (4) with the injection piston (3) connects.
    [2]
    2. Injection unit according to claim 1, characterized in that the energy accumulator is designed as a spring device (5).
    [3]
    3. Injection unit according to claim 1 or 2, characterized by an injection cylinder (6), in which the injection piston (3) is translationally movable.
    [4]
    4. Injection unit according to one of claims 1 to 3, characterized by a control or regulating unit (7), wherein by the injection piston (3) injection material (8) with a via the control or regulating unit (7) fixable standard injection pressure (Pstand ) can be injected into a cavity (9) of a molding tool (10) of the shaping machine (2).
    [5]
    5. Injection unit according to claim 4, characterized in that the spring device (5) has a rigidity (F) which essentially acts at a standard injection pressure (Pstand) from the injection material (8) on the injection piston (3) counterforce (G) equivalent.
    [6]
    6. Injection unit according to claim 5, characterized in that at a higher than the standard injection pressure (Pstand) increased injection pressure (P +) of the injection piston (3) against the stiffness (F) of the spring device (5) and under elastic deformation of the spring device ( 5) is movable relative to the drive device (4).
    [7]
    7. Injection unit according to one of claims 1 to 6, characterized in that the injection piston (3) as an injection screw (11) is formed, wherein the injection screw (11) of the drive device (4) is translationally and rotatably driven.
    [8]
    8. Injection unit according to one of claims 1 to 7, characterized in that the relative movement between the drive device (4) and injection piston (3) via at least one guide element (12) is guided.
    [9]
    9. Injection unit according to one of claims 1 to 8, characterized in that the spring device (5) a plurality, preferably arranged regularly about an injection unit longitudinal axis (L), springs (13), preferably coil springs.
    [10]
    10. Injection unit according to claim 9, characterized in that the drive device (4) has a drive motor (14), one of the drive motor (14) driven drive rod (15) and one with the drive rod (15) connected drive plate (16), wherein the Springs (13) of the spring device (5) on the drive plate (16) abut.
    [11]
    11. Injection unit according to claim 9 or 10, characterized in that the injection piston (3) has a piston shaft (17) on which abut the springs (13) of the spring device (5).
    [12]
    12. Injection unit according to claim 11, characterized in that the at least one, preferably rod-shaped, guide element (12) in the piston shaft (17) of the injection piston (3) is held and formed in a in the drive plate (16) of the drive device (4) Recess (18) is guided.
    [13]
    13. Injection unit according to claim 12, characterized in that each guide element (12) by a spring (13) of the spring device (5) is surrounded.
    [14]
    14. shaping machine (2), in particular injection molding machine, with at least one injection unit (1) according to one of claims 1 to 13. Innsbruck, 27 February 2014
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    同族专利:
    公开号 | 公开日
    DE102015002400A1|2015-09-17|
    US9498910B2|2016-11-22|
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    US20150246472A1|2015-09-03|
    CN104985779B|2017-07-28|
    CN104985779A|2015-10-21|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    ATA143/2014A|AT515479B1|2014-02-28|2014-02-28|Injection unit for a molding machine|ATA143/2014A| AT515479B1|2014-02-28|2014-02-28|Injection unit for a molding machine|
    DE102015002400.0A| DE102015002400A1|2014-02-28|2015-02-24|Injection unit for a molding machine|
    US14/632,263| US9498910B2|2014-02-28|2015-02-26|Injection assembly for a molding machine|
    CN201510235600.0A| CN104985779B|2014-02-28|2015-02-28|Injection unit for forming machine|
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