Check valve and method for manufacturing a check valve

Abstract

non-return valve (2, 102) comprising - a valve housing with a first housing part (4, 104) and a second housing part (6, 106, 206), wherein the first housing part (4, 104) and the second housing part (6, 106) are at least partially abutting and at least partially overlapping in a connecting area (16, 116), - a flexible valve diaphragm (8, 108) for opening and closing the check valve (2, 102), which is arranged inside the valve housing, in particular on a valve seat (10, 110) formed by the first housing part (4, 104), - a coating (22, 122) produced by injection molding, which encloses the connection area (16, 116) in such a way that the first housing part (4, 104) and the second housing part (6, 106) are pressure-tightly connected to each other, wherein the first housing part (4, 104) and the second housing part (6, 106) abut each other in the connection area (16, 116) at exactly one annular contact surface, wherein the annular contact surface is formed between end faces of a radially outwardly projecting annular projection (24, 124) of the first housing part (4, 104) and a radially outwardly projecting annular projection (26, 126) of the second housing part (6, 106), and wherein the first housing part (4, 104) has a further radially outwardly projecting, annular projection (32, 132) in the connection area (16, 116), which is formed on a front end section of the connection area (16, 116), and wherein the second housing part (6, 106) has a further radially outwardly projecting, annular projection (34, 134) in the connection area (16, 116), which is formed on a rear end section of the connection area (16, 116), and wherein the projections (32, 34, 132, 134) formed on the front and rear end sections of the connection area (16, 116) have a larger dimension in the radial direction than the projections (24, 124, 26, 126) forming the annular contact surface, and wherein the first housing part (4) has a recess (36, 136) formed between its projections (24, 32, 124, 132) and the second housing part (6) has a recess (38, 138) formed between its projections (26, 34, 126, 134).

Description

[0001] The invention relates to a check valve and a method for manufacturing a check valve.

[0002] Check valves are used in various applications, including motor vehicles, such as in brake boosters, where they are installed between a vacuum reservoir and a vacuum source. The check valve prevents fluid, particularly air, from flowing back from the vacuum source into the vacuum reservoir, ensuring that the vacuum is maintained even when the vacuum source is switched off and that brake assist is guaranteed. These check valves are also used for crankcase ventilation.

[0003] Check valves typically comprise a valve body with a first and a second body part, as well as a valve element, in particular a flexible valve diaphragm, for opening and closing the check valve, which is located inside the valve body. Due to the two-part design of the valve body, a connection point is created between the first and second body parts, which must be pressure-tight to ensure the proper functioning of the check valve. This has previously been achieved by joining the body parts using ultrasonic, rotary, laser, or induction welding after the check valve has been assembled. However, these processes are often messy and / or very expensive, particularly due to the investment costs for the welding equipment and the extended cycle time in the production of the check valves.Furthermore, additional time is required for transporting the check valves between the individual manufacturing steps and for subsequently testing the functionality of the check valves.

[0004] DE 20 2004 009 722 U1 discloses a check valve comprising a first hose connection housing and a second hose connection housing, and a diaphragm disc made of flexible material arranged between the two hose connection housings. This diaphragm disc is removable from an annular valve seat surrounding the inlet passage when overpressure occurs. The two hose connection housings are joined together by overmolding in an injection mold.

[0005] US 4,749,003 A discloses a check valve with a rotationally symmetrical valve body having fluid inlet and outlet ports centered on the axis of symmetry. A circular, flexible diaphragm is held inside the valve body by a retaining pin extending through a hole in the diaphragm. The retaining pin and an opposing receptacle for the retaining pin are supported by legs that project inward from the inlet and outlet walls of the valve body and bridge the inlet and outlet ports. The length of the legs determines the position of the diaphragm relative to the inlet wall against which the diaphragm seals, so that the valve's opening pressure depends on the length of the legs.

[0006] US 6,044,859 A discloses a valve comprising an inlet and an outlet housing, a flexible one-way valve, and a collar. The flexible valve is locked between the housings. The collar is attached to the inlet housing and extends into the flexible valve. As fluid flows through the valve, the collar supports the flexible valve and prevents it from collapsing due to backflow pressure.

[0007] EP 0 947 752 A1 discloses a threshold check valve comprising a reinforcement body which at least partially surrounds a two-part valve body.

[0008] The object of the invention is therefore to provide a check valve and a method for manufacturing a check valve in which the housing parts are or become connected in an improved pressure-tight manner with reduced effort and reduced costs.

[0009] The first-mentioned problem is solved by a check valve with the features according to claim 1. The check valve according to the invention comprises a valve housing with a first housing part and a second housing part, wherein the first housing part and the second housing part at least partially abut each other and at least partially overlap in a connection area. Furthermore, the check valve comprises a flexible valve diaphragm for opening and closing the check valve, which is arranged within the valve housing, in particular on a valve seat formed by the first housing part. The check valve further comprises an injection-molded casing which encloses the connection area in such a way that the first housing part and the second housing part are pressure-tightly connected to each other.The first housing part and the second housing part abut each other in the connection area at exactly one annular contact surface, wherein the annular contact surface is formed between the end faces of a radially outwardly projecting annular projection of the first housing part and a radially outwardly projecting annular projection of the second housing part. The first housing part has a further radially outwardly projecting annular projection in the connection area, formed at a front end section of the connection area, and the second housing part has a further radially outwardly projecting annular projection in the connection area, formed at a rear end section of the connection area.The projections formed at the front and rear end sections of the connection area are larger in the radial direction than the projections forming the annular contact surface. The first housing part has a recess formed between its projections, and the second housing part has a recess formed between its projections.

[0010] The first-mentioned problem is further solved by a check valve with the features according to claim 2. The check valve according to the invention comprises a valve housing with a first housing part and a second housing part, wherein the first housing part and the second housing part at least partially abut each other and at least partially overlap in a connection area. Furthermore, the check valve comprises a flexible valve diaphragm for opening and closing the check valve, which is arranged within the valve housing, in particular on a valve seat formed by the first housing part. The check valve further comprises an injection-molded casing which encloses the connection area in such a way that the first housing part and the second housing part are pressure-tightly connected to each other.The first housing part has a radially outwardly projecting projection in the connection area, and the second housing part has a radially outwardly projecting projection formed at a front and rear end section of the connection area, wherein further projections of the first housing part and further projections of the second housing part are formed within the connection area, flanked by recesses of the first housing part or the second housing part.

[0011] The term "abutting each other" means that the first and second housing parts each have one or more contact surfaces, particularly annular ones, which are in contact with each other when the check valve is assembled. The term "connection area" refers to an area extending both circumferentially and longitudinally along the check valve, in which the first and second housing parts abut each other at one or more contact surfaces, i.e., are in contact with each other, and which is enclosed by the casing.

[0012] The idea of ​​the invention is therefore to connect the housing parts of the valve housing in a pressure-tight manner by means of an enclosure. The enclosure surrounds the one or more contact surfaces formed between the housing parts in such a way that the interior of the valve housing is sealed from the environment in order to prevent air from escaping from the interior via the one or more contact surfaces between the housing parts.

[0013] The first and second housing parts feature projections and recesses in the joining area. This increases the contact area between the first and second housing parts, as well as the contact areas between the first housing part and the encapsulation and between the second housing part and the encapsulation, thereby improving the pressure-tight connection. Furthermore, in addition to the chemical bond at the interfaces, this creates a mechanical, positive-locking connection between the first housing part and the encapsulation and between the second housing part and the encapsulation. By positioning the projection at the front and rear end sections of the joining area, the first and second housing halves are held in axial position during overmolding with the encapsulation.

[0014] The casing is produced using injection molding. For this, the joining area is overmolded with an injection-moldable material, so that the casing completely encloses it and creates a pressure-tight connection. This eliminates the need for complex and expensive welding processes.

[0015] Preferably, the first housing part and / or the second housing part are also produced by injection molding. In particular, the first housing part and / or the second housing part and / or the outer casing are made of a plastic material, especially a thermoplastic material. This results in a chemical bond at the interfaces between the first housing part and the outer casing, as well as between the second housing part and the outer casing. Preferably, the two housing parts and the outer casing are produced in an injection molding machine with two or more injection units but only one clamping unit, known as multi-component injection molding. Preferably, the first and second housing parts are produced simultaneously in a first step, and the outer casing is produced in a further step.

[0016] In a preferred embodiment, the first and second housing parts form a collection chamber between them in the connection area, which is demarcated from the interior of the valve housing. This demarcation from the interior is achieved, in particular, by the first or the second housing part itself. The collection chamber is thus formed, for example, between overlapping end sections of the first and second housing parts. Furthermore, the collection chamber preferably borders one or more contact surfaces of the first and second housing parts. The collection chamber serves to collect any excess material from the casing during injection molding, preventing it from entering the interior of the valve housing. This ensures proper valve function, which is performed by the valve element located inside the housing.

[0017] The collection chamber is preferably annular in shape, extending in the circumferential direction of the check valve. This ensures that excess material can be collected across the entire circumference and distributed evenly within the collection chamber.

[0018] At least one projection and / or at least one recess is particularly ring-shaped, thus extending in the circumferential direction of the check valve.

[0019] The second problem is solved by a method for manufacturing a check valve with one or more of the properties described above, with the features according to claim 8.

[0020] The inventive method for manufacturing a check valve comprising a valve housing with a first housing part and a second housing part, and a valve element arranged within the valve housing, in particular a flexible valve diaphragm for opening and closing the check valve, by means of injection molding, i.e. in an injection molding machine, comprises the following steps: First, to produce the first housing part of the check valve, a material for the first housing part is plasticized and injected into a first mold, and to produce the second housing part of the check valve, a material for the second housing part is plasticized and injected into a second mold (step a)).

[0021] The check valve is then assembled such that the first and second housing parts abut each other at least partially at one or more contact surfaces in a connection area and overlap at least partially, in particular forming a collection chamber (step b)). For this purpose, the valve element is first positioned on a valve seat, which is formed in particular by the first housing part, and then the first and second housing parts are assembled. The pre-assembly of the valve element on the valve seat is carried out in particular by means of an automatic assembly unit within the injection molding machine. Subsequently, the first and second housing parts are brought into their final position, in which they abut each other at least partially at one or more contact surfaces or overlap at least partially.

[0022] In a further step (step c)), a material for the encapsulation is plasticized to form a pressure-tight encapsulation of the connection area, and the connection area is overmolded with it, so that the first and the second housing part are pressure-tightly connected to each other.

[0023] The first and second housing parts can, in principle, be manufactured sequentially, even with a time interval between their production. In an advantageous embodiment, the first and second housing parts are manufactured simultaneously, i.e., in a single operation, particularly on an injection molding machine with multiple injection units and a clamping unit.

[0024] The manufacturing of the casing of the check valve takes place in a further work step, whereby during the manufacturing of the casing of the check valve, in particular the manufacturing of a first and / or second housing part of another check valve takes place or can take place simultaneously.

[0025] To reduce time and transport distances, in a preferred embodiment, the check valve undergoes a functional test in a further step (step d)) after the coating has been formed. This is preferably carried out within the injection molding machine. The test includes, for example, checking the tightness of the valve housing and the valve itself, the opening and closing pressure of the valve, and its flow resistance.

[0026] The material used for the first housing part, the second housing part and / or the casing is in particular a material containing a thermoplastic polymer.

[0027] The check valve and the method according to the invention are explained in more detail below with regard to further features and advantages, based on the description of exemplary embodiments and with reference to the accompanying schematic drawings. Fig. 1 a check valve in a perspective view according to a first and second embodiment, Fig. 2. Turn off the check valve Fig. 1 in a top view, Fig. 3A a sectional view of the check valve from Fig. 1 and Fig. 2 according to the first embodiment, Fig. 3B a detailed view A of the check valve from Fig. 3A, Fig. 4A a sectional view of the check valve from Fig. 1 and Fig. 2 according to the second embodiment, Fig. 4B a detailed view B of the check valve from Fig. 4A, Fig. 5 a check valve in a perspective view according to a third embodiment, Fig. 6. Turn off the check valve Fig. 5 in a top view, Fig. 7A a sectional view of the check valve from Fig. 5 and Fig. 6 according to the third embodiment, Fig. 7B a detailed view C of the check valve from Fig. 7A.

[0028] Fig. 1 and Fig. Figures 2 and 2 each show a check valve 2, 102 in different representations according to a first and second embodiment. The check valve 2, 102 comprises a two-part valve housing with a first housing part 4, 104 and a second housing part 6, 106. Both the first housing part 4, 104 and the second housing part 6, 106 are made of a thermoplastic material and manufactured by injection molding.

[0029] The first housing part 4, 104 forms a first connection, the second housing part 6, 106 forms a second connection for integrating the check valve 2, 102 into a fluid, in this case air, indicated by arrows F drawn in the direction of flow, a piping system, for example for integration in the brake booster of a motor vehicle.

[0030] The check valve 2, 102 comprises a valve element 8, 108, in this case a flexible disc-shaped valve diaphragm, for opening and closing the check valve 2, 102, which is arranged inside the valve housing. The valve element 8, 108 is – as shown in the Fig. 3A and Fig. As shown in Figure 4A, the valve element 8, 108 is arranged on a valve seat 10, 110, which is formed by or integrally integrated with the first housing part 4, 104. The valve seat 10, 110 has a retaining element, in this case a projection 12, 112 extending in the flow direction F of the check valve 2, 102 in the form of a pin for holding the valve element 8, 108 in both the release and closed positions, the projection 12, 112 engaging in a through-opening of the valve element 8, 108. Additionally, the valve element 8, 108 is fixed between the first housing part 4, 104 and the second housing part 6, 106.

[0031] To open and close the check valve 2, 102, the valve seat 10, 110 has through-holes 14, 114 extending in the flow direction F and having, for example, a round or oval cross-section. In the release position, the valve element 10, 110 lifts at least partially from the through-holes 14, 114, allowing fluid to flow in the direction of flow from the interior of the first housing part 4, 104 through the through-holes 14, 114 into the interior of the second housing part 6, 106. In the closed position, the valve element 10, 110 closes the through-holes 14, 114, thus preventing fluid from flowing against the direction of flow F.

[0032] The check valve 2, 102 further comprises an injection-molded casing 22, 122 made of a thermoplastic material, which ensures a pressure-tight connection between the first housing part 4, 104 and the second housing part 6, 106. For this purpose, the casing 22, 122 encloses a connection area 16, 116 in which end sections 18, 118 of the first housing part 4, 104 and end sections 20, 120 of the second housing part 6, 106 abut each other at a contact surface, and the end sections 18, 118 of the first housing part 4, 104 and the end sections 20, 120 of the second housing part 6, 106 partially overlap (see Figure 1). Fig. 3A, Fig. 4A). The annular contact surface is formed in this case between end faces of an annular projection 24, 124 of the first housing part 4, 104 projecting radially outwards and an annular projection 26, 126 of the second housing part 6, 106 projecting radially outwards.

[0033] As seen especially in the detailed views Fig. 3B and Fig. As shown in Figure 4B, the first housing part 4, 104 and the second housing part 6, 106 form an annular collection chamber 28, 128 between them in the connection area 16, 116 to collect excess material from the casing 22, 122 during its manufacture by injection molding. The collection chamber 28, 128 is delimited from the interior of the valve housing by an annular projection 30, 130 extending circumferentially from the end section 20, 120 of the second housing part 6, 106, which in turn abuts an end section 18, 118 of the first housing part 4, 104. Furthermore, the collection chamber 28, 128 borders the contact surface of the first housing part 4, 104 and the second housing part 6, 106, through which the material can enter the collection chamber 28, 128.

[0034] The in Fig. 3A, Fig. embodiment shown in 3B and the embodiment shown in Fig. 4A, Fig. The two embodiments differ only in the shape of their projections 30 and 130. According to the first embodiment, the projection 30 extends from an inner side of the end section 20 of the second housing part 6 both longitudinally along the check valve (i.e., against the flow direction F) and radially, as well as annularly in the circumferential direction. According to the second embodiment, the projection 130 extends from an end face of the end section 120 of the second housing part 106 exclusively longitudinally along the check valve (i.e., parallel to it) and annularly in the circumferential direction. This avoids an undercut and thus a possible burr.

[0035] In addition to the projections 24, 124, 26, 126 forming a contact surface between the housing parts 4, 104, 6, 106, the first housing part 4, 104 has a further projection 32, 132 in the connection area 16, 116 projecting radially outwards, and the second housing part 6, 106 has a further projection 34, 134 projecting radially outwards in the connection area 16, 116. The projections 32, 132, 34, 134 are each formed on a front or rear end section of the connecting area 16, 116 and have a larger radial dimension than the projections 24, 26. Furthermore, the first housing part 4, 104 has a recess 36, 136 and the second housing part 6, 106 has a recess 38, 138, each formed between the projections 24, 32, 124, 132 and 26, 34, 126, 134, respectively.Both the projections 24, 32, 124, 132, 26, 34, 126, 134 and the recesses 36, 136, 38, 138 are in turn ring-shaped and extend circumferentially around the check valve 2, 102.

[0036] In the Fig. 5, Fig. 6, Fig. 7A and Fig. Figure 7B shows a check valve 202 according to a third embodiment. The check valve 202 comprises a two-part valve housing with a first housing part 204 and a second housing part 206, wherein both the first housing part 204 and the second housing part 206 are made of a thermoplastic material and by injection molding.

[0037] The first housing part 204 forms a first connection, the second housing part 206 forms a second connection for integrating the check valve 202 into a fluid-carrying system, in this case air, indicated by arrows F drawn in the direction of flow, for example for integration into the brake booster of a motor vehicle.

[0038] The check valve 202 comprises a valve element 208, in this case a flexible, disc-shaped valve diaphragm, for opening and closing the check valve 202, which is arranged inside the valve housing. The valve element 208 is arranged on a valve seat 210 formed by the first housing part 204. The valve seat 210, in turn, has a projection 212 in the form of a pin extending in the flow direction F of the check valve 202, serving as a retaining element in both the release and closed positions, and engaging in a through-opening of the valve element 208. Additionally, the valve element 208 is fixed between the first housing part 204 and the second housing part 206.

[0039] To open the check valve 202, the through-holes 214 arranged in the valve seat 210 are released by the valve element 208 at least partially lifting off the valve seat 210, allowing fluid to flow in the direction F from the interior of the first housing part 204 through the through-holes 214 into the interior of the second housing part 206. In the closed position, the valve element 210 closes the through-holes 214, thus preventing fluid from flowing against the direction F.

[0040] The check valve 202 further comprises an injection-molded casing 222 made of a thermoplastic material, which ensures a pressure-tight connection between the first housing part 204 and the second housing part 206. For this purpose, the casing 222 encloses a connection area 216 in which an end section 218 of the first housing part 204 and an end section 220 of the second housing part 206 abut each other at several contact surfaces, and the end section 218 of the first housing part 204 and the end sections 220 of the second housing part 206 partially overlap. The contact surfaces are formed between the end faces of the first housing part 204 and the second housing part 206, as well as an inside of the first housing part 203 and an outside of a projection 230 extending from the end section 220 of the second housing part 206 in the longitudinal direction of the check valve 202 and in a ring-shaped circumferential direction.

[0041] The first housing part 204 and the second housing part 206 form an annular collection chamber 228 between them in the connection area 216 to collect excess material from the casing 222 during its production by injection molding. The collection chamber 228 is separated from the interior of the valve housing, in this case by the projection 230 of the second housing part 206. Furthermore, the collection chamber 228 borders the contact surface of the first housing part 204 and the second housing part 206, through which the material can enter the collection chamber 228.

[0042] Furthermore, the first housing part 204 has a radially outwardly projecting projection 232 in the connection area 216, and the second housing part 206 has a radially outwardly projecting projection 234 in the connection area 216, which is formed at a front or rear end section of the connection area 216. Within the connection area 216, further projections 224 of the first housing part 204 and further projections 226 of the second housing part 206 are formed, which are flanked by recesses 236, 238 of the first and second housing parts 204, 206, respectively. The projections 224, 226 have a smaller dimension in both the longitudinal and radial directions than the projections according to the first and second embodiments, which makes it easier to melt the projections 224, 226 during overmolding, thus improving the connection between the two housing parts 204, 206 and the covering 222.

[0043] The check valves 2, 102, 202 are each manufactured by injection molding. For this purpose, a material for the first housing part 6, 106, 206, in this case a thermoplastic, is first plasticized and injected under pressure into a first mold or a first injection mold of an injection molding machine (step a)).

[0044] At the same time, a material for the second housing part 8, 108, 208, in this case a thermoplastic plastic, is plasticized and injected under pressure into a second mold or a second injection mold of the injection molding machine (step a)).

[0045] The check valve 2, 102, 202 is then assembled in the injection molding machine (step b)), whereby the valve element 8, 108, 208 is first positioned on the valve seat 10, 110, 210, which is formed by the first housing part 4, 104, 204, by means of an automatic assembly unit. Subsequently, the first housing part 4, 104, 204 and the second housing part 6, 106, 206 are arranged such that they at least partially abut each other at one or more contact surfaces in a connection area 16, 116, 216, and their end sections 18, 118, 218, 20, 120, 220 at least partially overlap.

[0046] In a further step (step c)), a material for the casing, also a thermoplastic, is plasticized and the connection area is overmolded under pressure in the injection molding machine. For this purpose, a mold or injection mold is used that creates a cylindrical outer contour of the casing. After the casing has cooled, the first housing part 4, 104, 204 and the second housing part 6, 106, 206 are pressure-tightly bonded together.

[0047] To check the tightness and other functions of the valve, the check valve 2, 102, 202 is subjected to a functional test in the injection molding machine after assembly. Reference sign 2, 102, 202 Check valve 4, 104, 204 first housing part 6, 106, 206 second housing part 8, 108, 208 Valve element 10, 110, 210 Valve seat 12, 112, 212 lead 14, 114, 214 passage openings 16, 116, 216 Connection area 18, 118, 218 End section of the first housing part 20, 120, 220 End section of the second housing part 22, 122, 222 Enclosure 24, 124, 224 lead 26, 126, 226 lead 28, 128, 228 Collection area 30, 130, 230 overhang 32, 132, 232 lead 34, 134, 234 lead 36, 136, 236 Exclusion 38, 138, 238 Exclusion

Claims

[1] Check valve (2, 102) comprising - a valve housing with a first housing part (4, 104) and a second housing part (6, 106, 206), wherein the first housing part (4, 104) and the second housing part (6, 106) at least partially abut one another in a connecting region (16, 116) and at least partially overlap, - a flexible valve membrane (8, 108) for opening and closing the check valve (2, 102), which is arranged within the valve housing, in particular on a valve seat (10, 110) formed by the first housing part (4, 104), - an enclosure (22, 122) produced by injection molding, which encloses the connecting region (16, 116) in such a way that the first housing part (4, 104) and the second housing part (6, 106) are connected to one another in a pressure-tight manner, wherein the first housing part (4, 104) and the second housing part (6, 106) abut one another in the connecting region (16, 116) at exactly one annular contact surface, wherein the annular contact surface is formed between end faces of a radially outwardly projecting, annular projection (24, 124) of the first housing part (4, 104) and a radially outwardly projecting, annular projection (26, 126) of the second housing part (6, 106), and wherein the first housing part (4, 104) in the connecting region (16, 116) has a further radially outwardly projecting, annular projection (32, 132) which is formed at a front end portion of the connecting region (16, 116), and wherein the second housing part (6, 106) has, in the connecting region (16, 116), a further radially outwardly projecting, annular projection (34, 134) formed at a rear end portion of the connecting region (16, 116), and wherein the projections (32, 34, 132, 134) formed on the front and rear end portions of the connecting region (16, 116) have a larger dimension in the radial direction than the projections (24, 124, 26, 126) forming the annular contact surface, and wherein the first housing part (4) has a recess (36, 136) formed between its projections (24, 32, 124, 132) and the second housing part (6) has a recess (38, 138) formed between its projections (26, 34, 126, 134). [2] Check valve (202) comprising - a valve housing with a first housing part (204) and a second housing part (206), wherein the first housing part (204) and the second housing part (206) at least partially abut one another in a connecting region (216) and at least partially overlap, - a flexible valve membrane (208) for opening and closing the check valve (202), which is arranged within the valve housing, in particular on a valve seat (210) formed by the first housing part (204), - an enclosure (222) produced by injection molding, which encloses the connecting region (216) in such a way that the first housing part (204) and the second housing part (206) are connected to one another in a pressure-tight manner, wherein the first housing part (204) has a projection (232) projecting outwards in the radial direction in the connecting region (216) and the second housing part (206) has a projection (234) projecting outwards in the radial direction, which projections are formed at a front and rear end section of the connecting region (216), and wherein further projections (224) of the first housing part (204) and further projections (226) of the second housing part are formed within the connecting region (216), which are flanked by recesses in the first housing part (204) or the second housing part (206). [3] Check valve (2, 102, 202) according to claim 1 or 2, wherein the first housing part (4, 104, 204) and / or the second housing part (6, 106, 206) and / or the casing (22, 122, 222) are formed from a plastic material, in particular a thermoplastic material. [4] Check valve (2, 102, 202) according to one of the preceding claims, wherein the first housing part (4, 104, 204) and the second housing part (6, 106, 206) form a collecting space (28, 128, 228) between them in the connecting region (16, 116, 216), which is delimited from an interior of the valve housing, in particular by the first housing part (4, 104, 204) or the second housing part (6, 106, 206). [5] Check valve (2, 102, 202) according to claim 4, wherein the collecting space (28, 128, 228) adjoins one or more contact surfaces of the first housing part (4, 104, 204) and the second housing part (6, 106, 206). [6] Check valve (2, 102, 202) according to one of claims 4 or 5, wherein the collecting space (28, 128, 228) is annular. [7] Check valve (2, 102, 202) according to one of the preceding claims, wherein the projection (224, 226, 232, 234) and / or the recess (36, 136, 236, 38, 138, 238) is annular. [8] A method for producing a check valve (2, 102, 202) according to any one of the preceding claims, comprising a valve housing with a first housing part (4, 104, 204) and a second housing part (6, 106, 206), and a flexible valve membrane (8, 108, 208) arranged within the valve housing for opening and closing the check valve (2, 102, 202), by means of injection molding, comprising the following steps: a) plasticizing a material for the first housing part (4, 104, 204) and injecting the material into a first mold to produce the first housing part (4, 104, 204) of the check valve (2, 102, 202) and plasticizing a material for the second housing part (6, 106, 206) and injecting the material into a second mold to produce the second housing part (6, 106, 206) of the check valve (2, 102, 202), b) mounting the check valve (2, 102, 202) such that the first housing part (4, 104, 204) and the second housing part (6, 106, 206) in a connecting region (16, 116, 216) at least partially abut one another on one or more contact surfaces and at least partially overlap, in particular forming a collecting space (28, 128, 228), c) plasticizing a material and overmolding the connecting region (16, 116, 216) to form an enclosure (22, 122, 222) of the connecting region (16, 116, 216), so that the first housing part (4, 104, 204) and the second housing part (6, 106, 206) are connected to one another in a pressure-tight manner. [9] Method according to claim 8, wherein the production of the first housing part (4, 104, 204) and the second housing part (6, 106, 206) takes place simultaneously. [10] Method according to one of claims 8 or 9, wherein the check valve (2, 102, 202) is subjected to a functional test in a further step. [11] Method according to one of claims 8 to 10, wherein a material containing a thermoplastic plastic is used as the material for the first housing part (4, 104, 204), the second housing part (6, 106, 206) and / or the sheath (22, 122, 222).

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