Injection mold for manufacturing a sealing ring

Abstract

Multi-part injection mold (100) for producing a sealing ring (1) in a mold cavity (2), comprising a first and a second outer part (4; 6) for forming a sealing base body (8), and a sleeve-shaped ejector (10) designed to eject the sealing ring (1), wherein the ejector (10) has an end face (42) for forming a side face (44) of the sealing base body (8), and an inner part arranged within the ejector (10) for forming an inner contour of the sealing ring (1) in the form of two sealing lips (14; 16), preferably angled to each other, characterized in that the inner part is formed in at least two parts.

Description

[0001] The present invention relates to a multi-part injection mold for producing a sealing ring according to the preamble of patent claims 1 and 10.

[0002] It is known from the prior art to produce sealing rings using an injection mold, wherein the injection mold is generally formed from at least two injection-molded parts, an injection- or nozzle-side injection-molded part and an ejector-side injection-molded part. Both injection-molded parts have cavity sections which, when the injection mold is assembled, complement each other to form a single mold cavity in the shape of the sealing ring to be formed. During injection molding, a material, such as a plastic, is liquefied and injected into the mold cavity under pressure. The injection-molded sealing ring then cools and can be removed in a solid state after the injection mold is opened. The sealing ring usually remains in the ejector side, from where it is then ejected by an ejector.

[0003] In order to create an injection mold for forming a sealing ring, milling or eroding are usually used, with the help of which hollow sections are incorporated into the injection molded parts to form the desired sealing elements, such as sealing lips.

[0004] However, a disadvantage of injection molds manufactured in this way is that complex and delicate structures in the cavity sections, which are desired, for example, for the formation of specially shaped sealing lips, cannot be formed in the injection molded parts by means of milling or eroding.

[0005] Alternatively, it is known to manufacture complex sealing elements individually and vulcanize them after joining them to a sealing ring. However, the disadvantage is that this type of sealing ring production is labor-intensive and costly.

[0006] JP 2005 - 343 065 A discloses a casting mold for a sealing ring, comprising a movable part and a stationary part. Each of the two parts is formed in two parts and coated with a thin layer of carbon.

[0007] DE 37 39 425 A1 describes the production of an oil seal using a mold assembly. The mold assembly comprises two relatively movable parts with surfaces that, in conjunction with a seal housing, define the formation of a mold cavity. This mold cavity has one region in the form of a sealing lip base body and another region in the form of a shoulder seal part.

[0008] DE 27 53 170 A1 relates to a method for producing a shaft seal with an elastomeric body and a molded lip. For this purpose, a ring of sintered polytetrafluoroethylene is formed into an intermediate layer in the form of a pressed or injection-molded lip, which is then bonded to the elastomeric body simultaneously with the pressing or injection-molded lip.

[0009] It is therefore an object of the present invention to provide a multi-part injection mold with which the formation of a sealing ring with complex sealing elements can be made possible.

[0010] This object is achieved by a multi-part injection mold for producing a sealing ring according to patent claims 1 and 10.

[0011] The following describes a multi-part injection mold for producing a sealing ring in a mold cavity. The multi-part injection mold comprises a first and a second outer part for forming a sealing base body and a sleeve-shaped ejector designed to eject the sealing ring. The ejector has an end face for forming a side surface of the sealing base body. Furthermore, the multi-part injection mold comprises an inner part arranged within the ejector for forming an inner contour of the sealing ring in the form of two sealing lips, preferably positioned at an angle to one another.

[0012] In order to form a sealing ring with complex and delicate sealing elements, particularly in the form of two sealing lips, preferably positioned at an angle to one another, it is proposed to form the inner part of the multi-part injection mold in at least two parts. This makes it possible to easily form a mold cavity section that enables the formation of fine structures, such as acute angles, in the sealing lips, which cannot be produced using methods known from the prior art, such as milling or erosion. The production of the two-part inner part for forming the proposed mold cavity section is significantly simpler and more cost-effective than the formation of an equivalent mold cavity section in a one-piece inner part.

[0013] According to an advantageous embodiment, the first inner part element is disc-shaped. It is provided that the first inner part element contacts the first outer part at least at the point at which the mold cavity forms a sealing edge of the first sealing lip. Furthermore, the first inner part element contacts the second inner part element at least at the point at which the mold cavity forms a sealing edge of the second sealing lip. Due to the separate design and the presented arrangement of the first inner part element, it is possible to form sealing lips with a particularly acute angle, so that sealing lips with sharp-edged sealing edges can be formed, which enable particularly good contact of the sealing lip with a component, for example with a shaft. The formation of such sealing edges is not possible with the methods known from the prior art.A further advantage of the separately formed, disc-shaped first inner part element is that only the first inner part element needs to be reworked, for example, to create a desired angle in the sealing lip. Another advantage is that the first inner part element can be reworked particularly easily, for example, by turning. It is possible to form the first inner part element in multiple parts.

[0014] In a further preferred embodiment, the first outer part and the first inner part element form a first mold cavity section that forms the first sealing lip. Furthermore, according to a further preferred embodiment, the two inner part elements form a second mold cavity section that forms the second sealing lip. It is preferred if, as a further embodiment shows, the first and second mold cavity sections have a V-shape or a Y-shape in cross-section. This allows an inner contour of the sealing ring to be formed that enables particularly good contact of the sealing lips with a component, for example, a shaft.

[0015] In a further preferred embodiment, the second inner part element is cylindrical with a flat outer surface that rests on an inner surface of the ejector. Furthermore, according to one embodiment, it is preferred if the second outer part has at least one sleeve-shaped inner surface that is flat. It is provided that an outer surface of the ejector rests on the inner surface of the second outer part. This makes it possible to manufacture and assemble the outer surface of the second inner part element, the inner surface of the second outer part, and the surfaces of the sleeve-shaped ejector in a particularly simple manner, for example by turning.

[0016] According to a further preferred embodiment, the outer surface of the second inner part element has a first radially larger outer surface and a second radially smaller outer surface. The ejector rests on the radially larger outer surface of the second inner part element. Furthermore, according to a further embodiment, it is preferred if the inner surface of the second outer part has a first radially larger inner surface and a second radially smaller inner surface, wherein the ejector rests on the radially smaller inner surface of the second outer part. Preferably, a transition between the first and second outer surface of the second inner part element and a transition between the first and second inner surface of the second outer part are designed as a step, and the end face of the sleeve-shaped ejector is flush with the step.As a result, the parting burrs that arise during injection molding on the side surface of the sealing base body to be formed, which arise at the parting planes of the ejector and the second inner part element or of the ejector and the second outer part, can be shifted so that the sealing base body rests directly against a component, for example a sealing ring carrier, during assembly.

[0017] In order to form a side surface of the sealing base body that rests even more optimally against the component, according to a further preferred embodiment, the end face of the ejector has an annular groove with a flat bottom surface, which is designed to form the side surface of the sealing base body. As a result, a mold cavity section can be formed on the end face of the ejector for forming a projection, in particular a step-shaped projection, on the side surface of the sealing base body. This allows receiving spaces to form on the edge of the formed projection, in which the separating burrs can be accommodated during assembly of the sealing ring.

[0018] According to a further preferred embodiment, the annular groove has two surfaces extending from the bottom surface toward the end face of the ejector, with at least one of the surfaces being angled outward. This allows a receiving space to be formed in the side surface of the sealing base body, which can be easily removed from the injection mold.

[0019] In the known ejectors, however, the ejector has a flat end face, which forms a flat side surface of the sealing base body. As a result, the burrs that form on the contact surfaces between the ejector and the outer or inner part cannot be accommodated in the receiving spaces. This leads to problems when assembling the sealing ring into a component that accommodates the sealing ring, such as a sealing ring carrier, because the burrs prevent the side surface of the sealing base body from directly contacting the sealing ring carrier. Instead, a gap can form between the side surface of the sealing base body and the sealing ring carrier.

[0020] Since this problem occurs with all ejectors regardless of the design of the inner part, a further aspect of the invention relates to a multi-part injection mold for producing a sealing ring in a mold cavity, with a first and a second outer part for forming a sealing base body, and with a sleeve-shaped ejector which is designed to eject the sealing ring, wherein the ejector has an end face for forming a side surface of the sealing base body, and with an inner part arranged within the ejector for forming an inner contour of the sealing ring in the form of two sealing lips arranged at an angle to one another.

[0021] To solve the problem of burrs, the end face of the ejector is provided with an annular groove with a flat bottom surface, which is designed to form the side surface of the sealing base body. This allows a side surface with a, in particular step-shaped, projection to be formed in the sealing base body, so that receiving spaces are formed at the edge of the projection, in which the burrs can be accommodated during assembly.

[0022] The invention will be described in more detail below with reference to exemplary embodiments illustrated in the drawings. The exemplary embodiments and the combinations shown in the exemplary embodiments are purely exemplary and are not intended to define the scope of the invention. This scope is defined solely by the appended claims.

[0023] They show: Fig. 1: a schematic spatial longitudinal sectional view through a multi-part injection mold according to the present invention; and Fig. 2: a detailed schematic cross-sectional view through the multi-part injection mold.

[0024] In the following, identical or functionally equivalent elements are identified by the same reference symbols.

[0025] Fig. 1 shows a schematic spatial longitudinal sectional view through a multi-part injection mold 100 for producing a sealing ring 1. The injection mold 100, when assembled, has a mold cavity 2 which is designed in the shape of the sealing ring 1. In Fig. For a better overview, Figure 2 shows a schematic detailed cross-sectional view of the multi-part injection mold 100 with the sealing ring 1.

[0026] As in Fig. 1 and Fig. As shown in Figure 2, the injection mold 100 has a first outer part 4 and a second outer part 6 for forming a sealing base body 8 of the sealing ring 1. Furthermore, the injection mold 100 has a sleeve-shaped ejector 10 designed to eject the formed sealing ring 1. Furthermore, the injection mold 100 has an inner part arranged within the ejector 10 for forming an inner contour in the form of two sealing lips 14, 16 of the sealing ring 1, which are positioned at an angle to one another.

[0027] The inner part, as shown in the Fig. 1 and Fig. 2, a first disc-shaped inner part element 18 and a second cylindrical inner part element 20. Due to the two-part design of the inner part of the injection mold 100, the two sealing lips 14, 16 to be formed, which are positioned at an angle to one another, can be formed particularly easily.

[0028] As particularly in Fig. 2, the inner part element 18 contacts the outer part 4 at the point where the mold cavity 2 forms a sealing edge 22 of the first sealing lip 14, and the second inner part element 20 contacts the outer part 4 at the point where the mold cavity 2 forms a sealing edge 24 of the second sealing lip 16. Due to the separate formation of the first inner part element 18 and its proposed arrangement between the first outer part 4 and the second inner part element 20, the two sealing lips 14, 16 can be formed with a particularly acute angle α1, α2, which cannot be produced using the methods known from the prior art.

[0029] As continued in Fig. 2, the outer part 4 and the first inner part element 18 form a first mold cavity section 26, which forms the sealing lip 14. Furthermore, the two inner part elements 18, 20 form a second mold cavity section 28, which forms the second sealing lip 16. In the embodiment shown, the first outer part 4 and the second inner part element 20 each have a nose 30, 32, so that the two mold cavity sections 26, 28 in the cross-sectional view of the Fig. 2 have a Y-shape.

[0030] As in Fig. 1, the second inner part element 20 has a flat outer surface 34, which rests on an inner surface 36 of the ejector 10. Furthermore, it is shown that the outer part 6 has a sleeve-shaped inner surface 38, which is flat and rests on an outer surface 40 of the ejector 10.

[0031] Alternatively, as in Fig. 2, the ejector 10 has an end face 42 for forming a side surface 44 of the sealing base body 8. To form the side surface 44, the outer surface 34 of the second inner part element 20 has a first outer surface part 35 with a small diameter d I and a second outer shell surface 37 with a large diameter D I The ejector 10 lies on the outer shell surface 37 with the large diameter D I Furthermore, the inner surface 38 of the second outer part 6 has a first inner surface 39 with a large diameter D II and a second inner shell partial surface 41 with a small diameter d II , wherein the ejector 10 is mounted on the inner shell surface 41 with the small diameter d IIrests. A transition between the first and second outer shell partial surfaces 35, 37 of the inner part element 20 and a transition between the first and second inner shell partial surfaces 39, 41 of the outer part 6 are formed as a step 46. The end face 42 of the ejector 10 is flush with the step 46.

[0032] Furthermore, the end face 42 of the ejector 10, as in Fig. 2, an annular groove 48 with a flat bottom surface 50, which is designed to form the side surface 44 of the sealing base body 8. As a result, a mold cavity section can be formed on the end face 42 of the ejector 10 for forming a, in particular step-shaped, projection in the side surface 44 of the sealing base body 8. The groove 48 can, as in Fig. 2, have two side surfaces 52, 54, which extend from the bottom surface 50 at an angle outwards in the direction of the end face 42 of the ejector 10. As a result, a receiving space for receiving the separating burrs can be formed in the side surface 44 of the sealing base body 8. Such a design of the ejector 10 can also be used with the flat support of the ejector 10 on the second inner part element 20 and the second outer part 6, as in Fig. 1 shown.

[0033] Overall, the multi-part injection mold presented here can be used to produce a sealing ring with complex and delicate sealing elements. The injection mold comprises a first and a second outer part, an ejector, and an inner part, with the inner part being formed in two parts. Alternatively or additionally, the ejector has an annular groove with a flat bottom surface on one end face, so that a mold cavity section can be formed for forming a projection on a side surface of the sealing base body to be formed. List of reference symbols 100 injection mold 1 sealing ring 2 mold cavity 4 first outer part 6 second outer part 8 Sealing base body 10 ejectors 14, 16 sealing lips 18 first inner part element 20 second inner part element 22, 24 sealing edges 26, 28 mold cavity section 30, 32 Nose 34 Outer surface of the second inner part element 35, 37 Outer shell surface of the second inner part element 36 Inner surface of the ejector 38 Inner surface of the second outer part 39, 41 Inner shell surface of the second outer part 40 Outer surface of the ejector 42 Front face of the ejector 44 Side surface of the sealing body 46th level 48 grooves 50 floor space 52, 54 Side surface of the groove α1, α2 angle of the sealing lip d I small diameter of the outer shell surface of the second inner part element D I large diameter of the outer shell surface of the second inner part element d II small diameter of the inner shell surface of the second outer part D IIlarge diameter of the inner shell surface of the second outer part

Claims

[1] Multi-part injection mold (100) for producing a sealing ring (1) in a mold cavity (2), with a first and a second outer part (4; 6) for forming a sealing base body (8), and with a sleeve-shaped ejector (10) which is designed to eject the sealing ring (1), wherein the ejector (10) has an end face (42) for forming a side face (44) of the sealing base body (8), and with an inner part arranged within the ejector (10) for forming an inner contour of the sealing ring (1) in the form of two sealing lips (14; 16) which are preferably set at an angle to one another, characterized by that the inner part is made up of at least two parts. [2] Multi-part injection mold (100) according to claim 1, characterized byin that the first inner part element (18) is disc-shaped and contacts the first outer part (4) at least at the point at which the mold cavity (2) forms a sealing edge (22) of the first sealing lip (14), and the first inner part element (18) contacts the second inner part element (20) at least at the point at which the mold cavity (2) forms a sealing edge (24) of the second sealing lip (16). [3] Multi-part injection mold (100) according to one of the preceding claims, characterized by that the first outer part (4) and the first inner part element (18) form a first mold cavity section (26) which forms the first sealing lip (14) and / or the two inner part elements (18; 20) form a second mold cavity section (28) which forms the second sealing lip (16). [4] Multi-part injection mold (100) according to claim 3, characterized bythat the first and second mold cavity sections (26; 28) have a V-shape or a Y-shape in cross section. [5] Multi-part injection mold (100) according to one of the preceding claims, characterized by that the second inner part element (20) is cylindrical with a flat outer surface (34) which rests on an inner surface (36) of the ejector (10) and / or the second outer part (6) has at least one sleeve-shaped inner surface (38) which is flat, wherein an outer surface (40) of the ejector (10) rests on the inner surface (38) of the second outer part (6). [6] Multi-part injection mold (100) according to one of the preceding claims, characterized bythat the outer jacket surface (34) of the second inner part element (20) has a first radially larger outer jacket partial surface (37) and a second radially smaller outer jacket partial surface (35), wherein the ejector (10) rests on the radially larger outer jacket partial surface (37) of the second inner part element (20). [7] Multi-part injection mold (100) according to the preceding claims, characterized by that the inner shell surface (38) of the second outer part (6) has a first radially larger inner shell partial surface (39) and a second radially smaller inner shell partial surface (41), wherein the ejector (10) rests on the radially smaller inner shell partial surface (41) of the second outer part (6). [8] Multi-part injection mold (100) according to claims 6 and 7, characterized bythat a transition between the first and second outer shell partial surface (35; 37) of the second inner part element (20) and a transition between the first and second inner shell partial surface (39, 41) of the second outer part (6) are designed as a step (46), and the end face (42) of the sleeve-shaped ejector (10) is flush with the step (46). [9] Multi-part injection mold (100) according to one of the preceding claims, characterized by that the end face (42) of the ejector (10) has an annular groove (48) with a flat bottom surface (50) which is designed to form the side surface (44) of the sealing base body (8). [10] Multi-part injection mold (100) for producing a sealing ring (1) in a mold cavity (2), with a first and a second outer part (4; 6) for forming a sealing base body (8), and with a sleeve-shaped ejector (10) which is designed to eject the sealing ring (1), wherein the ejector (10) has an end face (42) for forming a side surface (44) of the sealing base body (8), and with an inner part arranged within the ejector (10) for forming an inner contour of the sealing ring (1) in the form of two sealing lips (14; 16) arranged at an angle to one another, characterized by that the end face (42) of the ejector (10) has an annular groove (48) with a flat bottom surface (50) which is designed to form the side surface (44) of the sealing base body (8).

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