JP2011518698A - Casting apparatus for producing hollow casting articles using a non-rotationally symmetric projectile - Google Patents

Abstract

  A casting apparatus for producing a hollow casting article is filled with a cavity, a filling apparatus for filling a fluid casting material in the cavity, and a projectile (10) to drive the cavity. A displacement device configured to move into the casting material, preferably through the casting material, the projectile extending along a projectile longitudinal axis (12), The till (10) has a non-rotationally symmetric cross section in at least one axial contour section (48) of the longitudinally extending length of the projectile (10).

Description

  The present invention is a casting apparatus for producing a hollow casting article, wherein a cavity, a filling apparatus for filling a fluid casting material in the cavity, and a projectile are driven. A displacement device configured to move into the casting material filled in the cavity, preferably through the casting material, the projectile extending along the longitudinal axis of the projectile Concerning the format.

  An apparatus of this kind is known, for example, in EP 0757936A. This type of casting device, disclosed in this publication as an injection molding device, first fills the cavity with a fluid casting material and then partially passes the casting material filled in the cavity. Used to push away by a projectile driven for movement. The driving is performed by a fluid discharge nozzle. The fluid discharge nozzle directs the fluid under pressure to the prepared projectile, thereby driving the projectile.

  The projectile generally forms a hollow chamber when passing through the casting material filled in the cavity. The cross section of this hollow chamber substantially coincides with the projection of the projectile in the direction of the projectile longitudinal axis.

  In the above-mentioned publications, a sphere is described as an example of a projectile.

  Certainly, when a hollow article with a substantially circular inner contour is desired, the spheres will give good results, but in the field of producing a hollow sealed article to be cast, for example a seal tube made of elastomer, What is needed is a shape that deviates from an irregular, or circular cross-section, of the inner surface surrounding the hollow chamber of the casting article.

  It is therefore an object of the present invention to provide a casting device of the type described at the outset, a hollow casting article using this casting device, and a greater diversity in internal shape than was possible in the prior art. Along with this, it is an improvement to be manufacturable.

  This object is achieved in accordance with the invention in that the projectile has a non-rotationally symmetric cross section in at least one axial section of the length of the projectile extending in the longitudinal direction. It is solved by a casting device. This cross-section should be observed in a cross-sectional plane orthogonal to the projectile longitudinal axis. Preferably, in the non-rotationally symmetric contour section, a virtual envelope cylinder surrounding a radially outer side of the projectile has the projectile longitudinal axis as a cylinder axis, and the projectile includes It arrange | positions and is formed so that it may contact | connect in the area | region of the said contour division. Preferably, the projectile includes a projectile core having a projectile side surface, the projectile side surface extending radially outward from the projectile longitudinal axis, or / And at least one radial recess extending radially inward toward the projectile longitudinal axis. Preferably, the radial height of the radial protrusions and / or the radial depth of the radial recesses are at least partly with respect to the same projectile side without radial protrusions or / and radial recesses. Changes in the axial direction. Preferably, the radial height of the radial protrusion is axially increased at least partially from a leading end of the projectile to a trailing end. Preferably, at least one radial projection serves as a stabilizer rib that cooperates with a guide notch disposed in the cavity as the projectile passes through the cavity. Preferably, the stabilizer rib extends substantially over the entire axial length of the projectile. Preferably, at least one radial projection is at least one axial section of the projectile and at least one of the radial projections when viewed in a cross-section in a cross-sectional plane orthogonal to the projectile longitudinal axis. A radial section, preferably in the region of the radially outer end of the radial projection, having a circumferentially varying width about the projectile longitudinal axis, preferably Tapering toward the radially outer end of the radial projection. Preferably, the radial projection is at least one axial section of the projectile and at least a radially outer side of the radial projection when viewed in a cross-section in a cross-sectional plane orthogonal to the projectile longitudinal axis. In the region of the end, it has a triangular, trapezoidal or rectangular shape, preferably with rounded corners. Preferably, the transition part from the projectile core to the radial convex part is formed by being rounded in the circumferential direction. Preferably, at least one radial projection, in particular a radial projection forming a stabilizer rib, advantageously the radially outer end of said radial projection from said projectile core, said projectile core Projecting in the axial direction at the following longitudinal end. Preferably, the projectile includes a plurality of radial convex portions or / and radial concave portions, and these radial convex portions or / and radial concave portions are arranged at different intervals, particularly in the circumferential direction. ing. Preferably, the projectile includes a plurality of radial protrusions and / or radial recesses, and at least two radial protrusions or / and radial directions among these radial protrusions or / and radial recesses. The recesses have different radial dimensions and / or circumferential widths around the different projectile longitudinal axes, as seen in cross-sections in the same cross-sectional plane perpendicular to the projectile longitudinal axis, or / And different radial width variations. Preferably, the casting apparatus is an injection molding apparatus that uses a thermoplastic plastic as a casting material. Furthermore, the projectile for the injection molding method by the projectile injection technique according to the present invention has the above-described configuration.

  In the past, rotationally symmetrical projectiles have been used in the prior art exclusively based on the positional stability of the cavity as it travels, but at least partially non-rotationally symmetrical projectiles pointed out by the inventors of the present application. The possibility of using the present invention provides a significant extension of the formable inner surface shape of the hollow casting article produced by the casting device according to the present invention.

  As mentioned at the beginning, only the projection of the projectile in the direction of the projectile longitudinal axis serves to define the shape with respect to the internal shape of the hollow casting article. It is sufficient that one longitudinal section of the direction has a non-rotationally symmetric cross section. However, this should not exclude the possibility that the projectile has a non-rotationally symmetric cross section over substantially the entire axial length of the projectile.

  In this application, where it is generally stated that the filling device is configured to fill the cavity with a flowable casting material, this description should also include the only partial filling of the cavity with the casting material. is there. This is because it should not exclude the possibility that the casting material can be displaced from the filled portion of the cavity by the projectile and its movement into the originally unfilled section of the cavity.

  An axial longitudinal section of a projectile having a non-rotationally symmetric cross section is referred to herein as a “contour section”.

  In order to ensure that the contour section acts to impart shape to the casting material as it travels through the casting material filled in the cavity, the contour section is advantageously A virtual envelope cylinder that surrounds the outside in the radial direction has a projectile longitudinal axis as a cylinder axis, and is arranged and formed so as to contact the projectile in the region of the contour section of the projectile.

  In this application, the term “envelope cylinder” refers to a virtual cylinder whose cylinder axis coincides with the longitudinal axis of the projectile, and the diameter of the cylinder is that of the projectile. The point that is furthest away from the longitudinal axis of the projectile in the radial direction is selected to contact as a contact cylinder (Schmiegezylinder).

  A particularly often desired profile of the inner surface of the hollow casting article to be formed is a groove extending in the longitudinal direction of the casting article. The groove advantageously has a projectile core, wherein the projectile comprises a projectile side, the projectile side having at least one radial projection extending radially outward from the projectile longitudinal axis. It can be formed by providing.

  In addition or as an alternative, if it is conceivable to form the inner surface of the hollow casting article to be formed with protrusions extending in the longitudinal direction of the casting article, this is due to the projectile, The projectile side of the projectile can be achieved by providing at least one radial recess extending radially inward toward the projectile longitudinal axis.

  “Projectile core” refers to a substantially isomorphous projectile having no radial protrusions and / or no radial recesses. The term “projectile side” refers to the radially outward surface of the projectile. A section of the outer surface is radially outward when the normal vector of this section has a radially outward component with respect to the projectile longitudinal axis.

  In order to reduce the flow resistance of the projectile on entry into the casting material, and concomitantly, to reduce the energy required for driving the projectile, It is advantageous if the height or / and the radial depth of the radial recess vary at least partially in the axial direction with respect to a projectile core that does not have a radial projection or / and a radial recess.

  In this case, in particular, it is advantageous if the radial height of the radial projections increases in the axial direction at least partly from the leading end of the projectile towards the trailing end. In this case, it is particularly advantageous that the radial height of the radial projections increases continuously in the axial direction and without a step.

  When passing through the casting material filled in the cavity, the projectile may rotate about the longitudinal axis of the projectile. Nevertheless, if the hollow casting article that is desired to be formed is required only in the range of the end region in the vicinity of the projectile start position, the internal shape of the irregularly formed shape as prescribed is determined by the above-mentioned projectile. Satisfactory results can be achieved. This is because in the longitudinal direction of the tube, the internal profile, for example the internal profile of the tube, penetrates into the formed hollow casting article only along the predetermined penetration depth from said longitudinal end. This corresponds to the case where it is useful for connecting to the other article to be connected.

  However, the above rotation, which is not desirable as a projectile itself, around the longitudinal axis of the projectile as it travels through the cavity, causes the at least one radial protrusion to be projected over the entire projectile trajectory. As it passes through the cavity, it can be reduced or even prevented by serving as a stabilizer rib that cooperates with the corresponding guide notch.

  In this case, the guide notch guides the projectile by means of stabilizer ribs that enter the guide notch in the radial direction. It is particularly advantageous if the notch present in the cavity in any case for shaping the casting article can be used as a guide notch.

  Since the casting material filled in the cavities generally begins to cure first at the cavity walls, a hardened layer of casting material is formed at the guide notch that covers the wall area of the guide notch. As a result, the movement of the stabilizer ribs when passing through the cavity is substantially formed in the circumferential direction around the projectile trajectory, by a guide notch in a form coupling (form constraint) form, or in the guide notch. Limited by the layer of cured casting material without undesirable high flow resistance. This allows the guide notch to form a projectile anti-rotation means that resists rotation about the longitudinal axis of the projectile, possibly in the context of a hardened casting material layer in contact with the guide notch, more strictly In other words, it is formed over the entire projectile trajectory.

  A particularly stable and reliable guide can be obtained in an advantageous embodiment of the invention by the fact that the stabilizer ribs extend substantially over the entire axial length of the projectile.

  The particularly large variety of different possible shapes of the inner surface formed by the projectile of the hollow casting article is due to the fact that at least one radial projection is in a cross-sectional plane perpendicular to the projectile longitudinal axis. When viewed in cross section, it can be obtained by having a width that varies in the radial direction in at least one axial section of the projectile and at least one radial section of the radial projection. In this case, the width is to be measured in the circumferential direction around the projectile longitudinal axis. This type of width of the radial protrusion, depending on the radial position, is particularly important in the region of the radially outer end of the radial protrusion. This is because this type of width forms the bottom of the groove formed by the respective radial protrusion. If it is desired to reduce the flow resistance of the projectile as it passes through the casting material, the radial protrusion is advantageously formed to taper toward the radially outer end of the radial protrusion. It is good to be.

  In an advantageous structural configuration, the radial protrusions are at least one axial section of the projectile and at least the radial direction of the radial protrusions, as viewed in a cross-section in a cross-sectional plane perpendicular to the projectile longitudinal axis. In the region of the outer edge, it may have a triangular, trapezoidal or rectangular shape, preferably with rounded corners.

  The positional stability of the projectile during movement through the casting material filled in the cavity is further improved by the fact that the transition from the projectile core to the radial convex portion is formed by rounding in the circumferential direction. It can be improved. The transition with a clear ridge from the projectile core to the radial ridge may result in inconvenient turbulence or flow separation that can result in projectile drilling.

  Particularly high accuracy of the grooves formed in the hollow casting article by the radial protrusions can be achieved by the radial protrusions being in contact with the casting material over the largest possible axial length. is there. The at least one radial protrusion is from the projectile core to the subsequent longitudinal of the projectile core so as to provide as long a contact length as possible of the radial protrusion and at the same time a small projectile mass. It may protrude in the axial direction at the direction end. This is particularly true for the radial projections that form the stabilizer ribs. This is because the radial protrusions forming the stabilizer ribs have higher guide reliability as the length increases. It is particularly advantageous if the radially outer end of each radial projection projects axially from the projectile core more than the more radially inwardly located section of the radial projection. This is because the radially outer edge is generally formed with a small width in the circumferential direction around the projectile longitudinal axis, so that, despite its length, an excessively high flow This is because no resistance is formed.

  The shape of the inner surface of the hollow casting article desired to be formed can be selected in almost any form when the projectile is provided with a plurality of radial protrusions or / and radial recesses. Of course, in principle, it is also possible to arrange a plurality of radial protrusions and / or radial recesses around the projectile longitudinal axis at equal intervals in the circumferential direction. However, based on the greater structural freedom in the form of the inner surface of the hollow casting article, a plurality of radial protrusions or / and radial recesses are arranged at different intervals in the circumferential direction. And is particularly advantageous.

  The variety regarding the form of the inner surface of the hollow casting article that is desired to be formed is that the projectile comprises a plurality of radial protrusions or / and radial recesses, at least of these radial protrusions or / and radial recesses. Two radial projections or / and radial recesses in different radial dimensions or / and different projectile lengths as seen in cross-section in the same cross-sectional plane perpendicular to the projectile longitudinal axis Further improvements can be achieved by having a circumferential width around the directional axis and / or different radial width variations.

  In principle, the casting device according to the present invention should be operable with any casting material. However, advantageously, the above-described casting apparatus is an injection molding apparatus that processes thermoplastic as the casting material.

  The above-mentioned problems of the present invention are also solved by a projectile for an injection molding method according to the projectile injection technology, which is formed according to at least one of the above-mentioned aspects. Since this type of projectile is an article that can be handled independently, the applicant requests independent patent protection for the projectile based on the same basic idea of the invention.

  It is supplemented that it is advantageous if the projectile tapers along the projectile longitudinal axis towards the preceding longitudinal end in order to reduce flow resistance.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

It is the perspective view which looked at the projectile of the casting apparatus which concerns on this invention from diagonally back. FIG. 2 is a side view of the projectile according to FIG. 1. FIG. 3 is a rear view of the projectile according to FIGS. 1 and 2. FIG. 4 is a cross-sectional view of a hollow casting article formed by the casting apparatus according to the present invention and the projectile according to FIGS. 1 to 3.

  1 to 3, reference numeral 10 is assigned to the entire projectile for use in the casting apparatus according to the present invention. The projectile 10 extends along the projectile longitudinal axis 12 and has a longitudinal end 14 that precedes the projectile motion direction B and a longitudinal end 16 that follows.

  The projectile comprises a projectile core 18 with a prudentile side 20 that is substantially rotationally symmetric in the embodiment according to FIGS. The projectile core 18 is a portion of the projectile 10 that is located radially inward of the lines 22, 24, and 26.

  The projectile side surface 20 has a first region 20 a including the preceding longitudinal end 14 of the projectile 10. In the first region 20 a, the projectile 10, in particular the projectile core 18 tapers in the direction of the projectile longitudinal axis 12 toward the preceding longitudinal end 14 of the projectile 10. Further, the projectile side surface 20 has a second region 20b. In the second region 20b, at least the projectile core 18 has a substantially columnar or cylindrical outer surface or, more generally defined, a cross section perpendicular to the projectile longitudinal axis 12. Has an outer surface that does not change along the projectile longitudinal axis 12. The boundary between the two regions 20a and 20b is indicated by a broken line 28.

  From the periphery of the projectile 10, three radial protrusions are formed on the radially outer side of the projectile core 18. Of the three radial protrusions, two substantially identical radial protrusions 30 and 32 are located diametrically opposite with respect to the projectile longitudinal axis 12. A third radial projection 34 extending radially outward from the radial projections 30 and 32 is a circumferential direction around the projectile longitudinal axis 12 and is more radial than the radial projection 30. It is located near the convex part 32.

  All the radial protrusions 30, 32, 34 have first regions 30a, 32a, 34a, similar to the projectile 10 itself. In the first regions 30 a, 32 a, 34 a, the radial height of the radial protrusions 30, 32, 34 with respect to the projectile core 18 extends along the projectile longitudinal axis 12 with respect to the preceding of the projectile 10. Gradually and continuously from the longitudinal end 14 to the subsequent longitudinal end 16.

  Similarly, each of the radial protrusions 30, 32, 34 has second regions 30 b, 32 b, 34 b adjacent to the first regions 30 a, 32 a, 34 a in the direction of the projectile longitudinal axis 12. In the second sections 30b, 32b, and 34b, the cross-sections of the respective radial protrusions 30, 32, and 34 are the cross-sectional plan view orthogonal to the projectile longitudinal axis 12, and the projectile longitudinal axis 12 Is invariant along.

  The boundary between the first region and the second region of the radial protrusions 30, 32, 34 is indicated by a dashed line drawn partially around the projectile longitudinal axis 12. More precisely, the radial convex portion 30 is indicated by a broken line 36, the radial convex portion 32 is indicated by a broken line 38, and the radial convex portion 34 is indicated by a broken line 40.

  The radial protrusions 30, 32 are formed with a substantially triangular cross section and are defined by a substantially flat surface at least in the region of the radially outer end. In order to reduce the flow resistance of the projectile and to stabilize the position of the projectile in motion through the flowable casting material, in the vicinity of the projectile core 18 of the radial projections 30, 32, respectively. On the base located at, concave rounded portions 42 and 44 are formed. Due to the rounded portions 42 and 44, the projectile core 18 which is convex in the circumferential direction of the projectile 10 is substantially stepless from the projecting core 18 in the radial direction to the substantially flat defined surface of the radial projections 30 and 32. The smooth transition part is formed. The circumferential extension length of the circumferential regions of the rounding portions 42 and 44 is indicated by a broken line.

  As can be seen in FIGS. 1 and 3, the radial protrusion 34 is defined by a curved outer surface. The curved outer surface is in contact with the projectile core 18 in a stepless manner to form a smooth transition portion. A circumferential region in which the radial protrusion 34 extends in the projectile core 18 is indicated by a broken line 46.

  As can be seen in FIG. 2, the radial protrusion 34 extends substantially over the entire axial length of the projectile 10. As a result, the contour section 48 extends substantially over the entire axial length of the projectile.

  The radial protrusions 34, which have a significantly larger radial extension length compared to the radial protrusions 30, 32, serve as stabilizer ribs in the embodiment shown in FIGS. Stabilizer ribs interact with the guide notches corresponding to the radial projections 34 of the cavity as the projectile 10 moves through the casting mold cavity and during movement through the cavity. , Avoid or at least reduce rotation of the projectile 10 about the projectile longitudinal axis 12.

  The substantially identical radial projections 30, 32 are shorter in the axial direction and reach the subsequent longitudinal end 16 of the projectile, but the radial projections 34. Compared to the above, the leading end is located farther from the preceding longitudinal end 14.

  In FIG. 3, an envelope cylinder 50 is schematically shown. The cylinder longitudinal axis 52 of the envelope cylinder 50 coincides with the projectile longitudinal axis 12. The envelope cylinder 50 is in contact with the projectile 10 as a contact cylinder at a point 54 that is farthest from the projectile longitudinal axis 12 in the radial direction of the projectile 10.

  FIG. 1 supplements that the surfaces 56, 58, 60, 62 are seen in the region of the subsequent longitudinal end 16 of the projectile 10. These surfaces 56, 58, 60, 62 serve to accommodate the projectile in the fluid discharge nozzle.

  FIG. 4 shows a cross section of a tube with a continuous internal shape produced by an injection molding device according to the invention without hatching. This constituent member is denoted by reference numeral 64.

  On the inner surface 66 of the component 64 formed by the projectile 10, two grooves having a triangular cross section formed by the radial protrusions 30 and 32 can be seen. More precisely, the groove 68 corresponds to the radial protrusion 32 and the groove 70 corresponds to the radial protrusion 30.

  A deeper groove 72 between the groove 68 and the groove 70 is formed by the radial protrusion 34. The mold notch that forms the convex portion 74 of the component 64 of the cavity forming the entire component 64 is a guide notch and has a radius to prevent rotational movement of the projectile 10 about the projectile longitudinal axis 12. It cooperates with the direction convex part 34.

  At that time, first, in the cavity, in particular in the regions 76 and 78, the guide wall of the guide notch forming the convex portion 74 was guided to guide the radial convex portion 34 during the movement of the projectile 10 passing through the cavity. A zone of casting material is formed.

Claims (15)

A casting device for producing a hollow casting article,
-A cavity,
-A filling device for filling the cavity with a fluid casting material;
A displacement device configured to drive the projectile (10) to move into the casting material filled in the cavity, preferably through the casting material;
Wherein the projectile extends along a projectile longitudinal axis (12), the projectile (10) having a longitudinal extension length of the projectile (10). Casting device for producing a hollow casting article, characterized in that it has a non-rotationally symmetric cross section in at least one axial contour section (48).   In the non-rotationally symmetric contour section (48), the virtual envelope cylinder (50) surrounding the radially outer side of the projectile (10) has the projectile longitudinal axis (12) as the cylinder axis (52). The casting apparatus according to claim 1, wherein the casting apparatus is arranged and formed so as to be in contact with the projectile in a region of the contour section of the projectile.   The projectile (10) comprises a projectile core (18) comprising a projectile side surface (20), the projectile side surface (20) extending radially outward from the projectile longitudinal axis (12). At least one radial projection (30, 32, 34) present, and / or at least one radial recess extending radially inward towards the projectile longitudinal axis (12). Item 3. A casting apparatus according to item 1 or 2.   The radial height of the radial projection (30, 32, 34) and / or the radial depth of the radial recess is the radial projection (30, 32, 34) or / and the radial recess. 4. Casting device according to claim 3, wherein the casting device changes at least partly in the axial direction with respect to the same projectile side (20) not having any.   The radial height of the radial projections (30, 32, 34) is axial and increases at least partially from the leading end (14) to the trailing end (16) of the projectile. The casting apparatus according to claim 4.   At least one radial protrusion (34) serves as a stabilizer rib that cooperates with a guide notch disposed in the cavity as the projectile (10) passes through the cavity. The casting apparatus according to any one of 5 to 5.   The casting device according to claim 6, wherein the stabilizer rib (34) extends substantially over the entire axial length of the projectile (10).   At least one radial protrusion (30, 32, 34) is at least one axial direction of the projectile (10) when viewed in a cross-section in a cross-sectional plane perpendicular to the projectile longitudinal axis (12). The projectile in the section and at least one radial section of the radial projection (30, 32, 34), preferably in the region of the radially outer end of the radial projection (30, 32, 34). It has a circumferentially varying width around the longitudinal axis (12), preferably tapering towards the radially outer end of the radial projection (30, 32, 34) The casting apparatus according to any one of claims 3 to 7.   The radial protrusions (30, 32) are at least one axial section of the projectile (10) and at least the cross-section in a cross-sectional plane perpendicular to the projectile longitudinal axis (12). From the region of the radially outer end of the radial projection (30, 32), it has a triangular, trapezoidal or rectangular shape, preferably with rounded corners. The casting apparatus according to any one of up to 8.   The transition part from the said projectile core (18) to the said radial direction convex part (30,32,34) is rounded in the circumferential direction, and is formed in any one of Claim 3-9 Casting equipment.   At least one radial protrusion (30, 32, 34), in particular a radial protrusion (34) forming a stabilizer rib, preferably the radially outer end of said radial protrusion, is said projectile. 11. Casting device according to any one of claims 3 to 10, in particular including claim 6, projecting axially from the core (18) at the subsequent longitudinal end of the projectile core (18). .   The projectile (10) includes a plurality of radial protrusions (30, 32, 34) or / and radial recesses, and these radial protrusions (30, 32, 34) or / and radial recesses. The casting apparatus according to any one of claims 3 to 11, wherein the casting apparatus is disposed at different intervals, particularly in the circumferential direction.   The projectile (10) comprises a plurality of radial protrusions (30, 32, 34) or / and radial recesses, and these radial protrusions (30, 32, 34) or / and radial recesses Of which, at least two radial protrusions (30, 32, 34) or / and radial recesses are seen in a cross section in the same cross-sectional plane perpendicular to the projectile longitudinal axis (12), 13. Any one of claims 3 to 12, having different radial dimensions or / and different circumferential widths or / and different radial width variations around the different projectile longitudinal axes (12). The casting device described.   The casting apparatus according to any one of claims 1 to 13, wherein the casting apparatus is an injection molding apparatus using a thermoplastic plastic as a casting material.   A projectile for an injection molding method according to the projectile injection technique, comprising the configuration according to claim 1 and optionally the other configuration according to any one of claims 2 to 13.

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