SEALING ARRANGEMENT

Description

[0001] The present invention relates to a sealing arrangement for use in a fluid valve having a housing and a flap, a fluid valve with the sealing arrangement, a fuel cell arrangement with the fluid valve, a motor vehicle with the fluid valve and a method for assembling the fluid valve.

[0002] From internal practice, valve flaps are known for blocking gas lines. These valve flaps pivot around a central axis in the valve opening (so-called butterfly valves) or pivot around a lateral hinge axis onto a valve seat (so-called hinge or door valves) to block a valve opening.

[0003] US2016 / 138719A1 and DE7006387U disclose sealing arrangements according to the preamble of claim 1.

[0004] An object of an embodiment of the present invention is to improve a sealing arrangement for use in a fluid valve having a housing and a flap.

[0005] This object is achieved by a sealing arrangement having the features of claim 1. Claims 7 to 13 protect a fluid valve, and claims 14, 15 and 16 protect a fuel cell arrangement or a motor vehicle with a fluid valve described here, as well as a method for assembling the fluid valve.

[0006] According to one embodiment of the present invention, a sealing arrangement is provided for use in a fluid valve comprising a housing and a flap, which is configured to control fluid flow through a valve opening of the fluid valve by adjusting a position of the flap between a closed position and an open position. According to one embodiment, the sealing arrangement comprises a retaining ring with a retaining ring contact portion and a plurality of legs, and an annular, flexible sealing element having a circumferential radial ridge and a first radial surface adjacent to the radial ridge, which is on the upstream side during intended use and is configured to function as a centering surface for a press fit with a corresponding counter-centering surface of an inner wall of the housing, wherein a first side surface of the radial ridge, which is on the upstream side during intended use, is providedto bear against a contact surface of the inner wall of the housing, the retaining ring contact section has a retaining ring contact surface which, during intended use, is intended to bear against a second side surface of the radial web which is downstream during intended use, and free ends of at least a subset of the plurality of legs are intended, during intended use, to be supported under prestress on a support section of the inner wall of the housing which extends substantially perpendicular to the flow direction of the fluid.

[0007] An open position referred to here can, in one embodiment, be an (open) end position of the valve. Accordingly, the valve arrangement or opening in one embodiment is fully or maximally open when the valve is in this open or open end position. Likewise, an open position referred to here can also be between the closed and (open) end positions.

[0008] By using the combination of the flexible sealing element and the retaining ring, in one embodiment, the flexible sealing element can advantageously be held in place by, on the one hand, the (radially acting) compressive force generated by the interference fit between the first radial surface of the annular radial web and the counter-centering surface of the inner wall of the housing, and, on the other hand, by the spring force generated in the axial direction by the free ends of the legs of the retaining ring, which are supported under preload on the support section of the inner wall of the housing. Furthermore, in one embodiment, a radial fixation of the sealing element can be achieved in a simple and cost-effective manner.

[0009] The sealing element can be made from a variety of flexible materials, including special low-friction materials such as ethylene propylene diene rubber (EPDM). To improve the friction properties and thus improve the sealing element's fixation, the sealing element can be additionally coated with a suitable material.

[0010] The retaining ring can be manufactured, for example, using a sheet metal stamping process. In one embodiment, the retaining ring is manufactured from a continuous piece of sheet metal, with the legs being formed by cutting or punching a sheet metal. In one embodiment, the cuts / punching processes are carried out such that they have the smallest possible width permitted by the respective manufacturing process. In one embodiment, the cuts are made starting from the side of the retaining ring contact section in order to advantageously prevent the formation of sharp edges that could cause damage to the sealing element. In one or more embodiments, the legs of the retaining ring have one or more bends and / or are elastically deformable.

[0011] In one embodiment, a thickness of the radial ridge, measured in the axial direction of the sealing element, taking into account manufacturing tolerances and the influence of thermal effects, is selected such that the radial ridge provides a suitable degree of compressive force / resistance when the retaining ring abutment surface presses it against the abutment surface of the inner wall of the housing, in order to ensure that the free ends of the (elastic) legs of the retaining ring can return to their original state during assembly from a bent state caused by contact with the inner wall of the housing in order to bear against the support section.

[0012] According to the invention, the sealing element has a circumferential sealing lip which, during intended use, extends upstream and toward the inner wall of the housing, and whose inner circumferential surface forms a valve seat that defines the valve opening and is intended to be contacted by the flap in the closed position of the fluid valve. Thus, the sealing element can be functionally divided into two sections: an inner section, which has the inner circumferential surface of the sealing lip and is intended for the primary sealing function of the valve and for optimizing the fluid flow across itself, and an outer mounting section, which fulfills both the function of fastening in the flow channel for the fluid formed by the housing and a secondary sealing function.

[0013] According to the invention, a recess is formed between a section of the sealing element having the first radial surface and the sealing lip.

[0014] This allows the sealing element, in particular the sealing lip, to expand elastically in the direction of the inner wall of the housing when the fluid valve, in particular the flap for opening / closing the valve opening, moves.

[0015] In one embodiment, the recess is designed with a large radius curve at its base to reduce mechanical stress in this area and thus increase the service life of the sealing element. This design also allows for a pressure differential between the two sides (upstream side / downstream side) of the valve to further increase or decrease the contact pressure of the sealing lip against the flap, depending on which pressure is higher.

[0016] In one embodiment, an upstream end portion of the portion of the sealing element having the first radial surface tapers radially inwardly.

[0017] In one embodiment, this can facilitate the insertion of the sealing element into the housing section with the counter-centering surface during assembly of the fluid valve. Since a press fit occurs between the first radial surface and the counter-centering surface, the seal between the sealing element and the housing is also ensured.

[0018] In one embodiment, the sealing element has a second radial surface adjacent to the radial web, which, during intended use, is located downstream and is offset radially inward relative to the first radial surface. In one embodiment, the second radial surface extends parallel, or at least substantially parallel, to the flow direction of the fluid.

[0019] In one embodiment, a downstream end portion of the portion of the sealing element having the second radial surface tapers radially inward.

[0020] Furthermore, in the intended use, in particular the retaining ring contact section can be arranged between the second radial surface and the inner wall of the housing, wherein the retaining ring can be arranged at a distance from the second radial surface.

[0021] In one embodiment, the plurality of legs extend radially outwardly at an obtuse angle with respect to the (flat) retaining ring abutment portion via an outer curved portion.

[0022] The radius of the bent section can be selected larger than specified during manufacturing to ensure that the spring effect and the bending occur precisely at the radius. In particular, an outer diameter of the retaining ring, defined by the free ends of at least a subset of the plurality of legs, is larger than an inner diameter of a portion of the housing that surrounds the retaining ring during intended use in an installed state. In this way, these legs are in an elastically deformed state in the installed state, and thus, in one embodiment, it can advantageously be ensured that the ends are supported on the support section under the preload.

[0023] The width of the (bent) legs of the retaining ring is selected depending on the conflicting requirements regarding the resistance to plastic deformation during assembly and the spring force acting in the radial direction, which serves both to center the retaining ring and, if applicable, the sealing element, and to prevent the retaining ring and thus also the sealing element from becoming loose from the installed position during operation of the fluid valve.

[0024] In one embodiment, one or more of the legs are shorter or cut off to create clamping surfaces required for the manufacturing process. The shorter legs are chosen to be evenly distributed in a circle to avoid an imbalance in the radial spring force generated by the (longer) legs.

[0025] In one embodiment, the retaining ring has an inner curved portion which, during intended use, extends substantially in the downstream direction from the retaining ring abutment portion and, in particular, is opposite the second radial surface of the radial web.

[0026] In one embodiment, this can increase the rigidity of the retaining ring.

[0027] In one embodiment, the first side surface and / or the second side surface of the radial web is formed as a structured surface and / or has at least one annular rib.

[0028] In one embodiment, the first side surface of the radial web can thereby ensure the hold when pressed against the contact surface of the inner wall of the housing in the axial direction and the tightness against air escaping from the fluid valve, and the second side surface can ensure the hold when compressed by the retaining ring contact surface.

[0029] According to one embodiment of the present invention, a fluid valve, in particular for a gas line, in particular of a fuel cell and / or a motor vehicle drive, comprises a housing with an inner wall, a flap, and a sealing arrangement as described above, wherein the fluid valve is configured to control a fluid flow through a valve opening of the fluid valve by adjusting a position of the flap between a closed position and an open position, wherein the inner wall of the housing has the counter-centering surface, the contact surface, and the support section, the first radial surface of the sealing element bears against the counter-centering surface under prestress, the first side surface of the radial web bears against the contact surface, the retaining ring contact surface bears against the second side surface of the radial web, and free ends of at least a subset of the plurality of legs are supported on the support section under prestress.

[0030] In In one embodiment, the sealing element has the circumferential sealing lip, wherein the inner wall has a widening section adjoining the counter-centering surface upstream, and an outer peripheral surface of the sealing lip is spaced from the widening section and opposite it.

[0031] In In one embodiment, the inner wall has a straight section adjoining the widening section upstream, which extends parallel to the flow direction of the fluid.

[0032] In one embodiment, this advantageously provides clearance for the movement of the sealing lip. Furthermore, the transitions between the individual sections of the inner wall can be rounded to avoid sharp edges that could cause damage.

[0033] In In one embodiment, the inner wall has a section adjoining the counter-centering surface downstream, which section extends radially outward perpendicular to the flow direction of the fluid and has the contact surface.

[0034] This section adjusts the tolerance of the press fit in the closed position of the flap by the distance to a rotation axis of a shaft with which the flap is moved.

[0035] In one embodiment, the inner wall has a further section adjoining the section adjoining the counter-centering surface downstream, which further section extends parallel to the flow direction of the fluid, wherein a partial section of the further section is opposite an outwardly facing upper side of the radial web and is spaced therefrom.

[0036] In one embodiment, this allows movement of the legs of the retaining ring to be limited in the radial direction.

[0037] In one embodiment, the support section adjoins the further section downstream and extends radially inward from the further section.

[0038] In one embodiment, the inner wall has a further section adjoining the support section downstream, comprising a first section adjoining the support section and extending parallel to the flow direction of the fluid, and a second section adjoining the first section and widening.

[0039] According to one embodiment of the present invention, a fuel cell arrangement, in particular for a motor vehicle drive, comprises at least one fuel cell, at least one gas line, in particular for supplying and discharging gas to and from the fuel cell, and a fluid valve as described above for blocking the gas line by adjusting the flap to the closed position.

[0040] According to one embodiment of the present invention, a motor vehicle has at least one fluid valve as described above, in particular for blocking a line, in particular a gas line, of the motor vehicle, in particular a motor vehicle drive and / or fuel cell arrangement line, by adjusting the flap into the closed position.

[0041] According to one embodiment of the present invention, a method for assembling a fluid valve as described above comprises the steps of: providing the housing with a bore, Inserting a shaft through the bore, inserting the flap from a downstream side of the housing and mounting the flap on the shaft, inserting the sealing element from the downstream side of the housing such that the first side surface of the radial web bears against the contact surface of the inner wall of the housing, and the first radial surface bears against the counter-centering surface of the inner wall of the housing, and inserting the retaining ring from the downstream side of the housing such that the free ends of at least a subset of the plurality of legs are elastically bent radially inward during insertion due to contact with the inner wall of the housing, and after passing through the support section, snap back radially outward due to a spring force of the legs when the retaining ring is pressed with the retaining ring contact surface against the second side surface of the radial web,that the radial web is compressed along the flow direction of the fluid.

[0042] Further advantages and features emerge from the subclaims and the exemplary embodiments. The following shows, partly schematically: Fig. 1 is a cross-sectional view of a fluid valve with a sealing arrangement according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of a retaining ring of the sealing arrangement, Fig. 3 is a plan view of the Fig. 2 shown retaining ring, and Fig. 4 a perspective cross-sectional view of the fluid valve.

[0043] Fig. 1 shows a fluid valve with a sealing arrangement according to an embodiment of the present invention. Fig. 2 shows a cross-sectional view of a retaining ring of the sealing assembly. Fig. 3 shows a top view of the Fig. 2 shown retaining ring, and Fig. 4 shows a perspective cross-sectional view of the fluid valve.

[0044] The fluid valve 10 comprises a housing 20, a flap 30 and a sealing arrangement 100 accommodated in the housing 20, and is designed to control a fluid flow of a fluid in a fluid, in particular gas, line into which the fluid valve 10 is connected or installed, which in Fig. 1 as illustrated by the arrow P flows from top to bottom, through a valve opening of the fluid valve 10 by adjusting a position of the flap 30 by means of a shaft 40 connected to the flap 30 by screws 41, as in Fig. 4 illustrated is inserted through a bore of the housing 20, between a closed position and an open position.

[0045] The sealing arrangement 100 comprises a retaining ring 110 with a retaining ring abutment portion 111 and a plurality of legs 112, and an annular, flexible sealing element 200 having a circumferential radial ridge 201 and an upstream first radial surface 202 adjacent to the radial ridge 201, which serves as a centering surface for a press fit with a corresponding counter-centering surface 23 of an inner wall 21 of the housing 20.

[0046] An upstream first side surface 203 of the radial web 201 bears against a contact surface 22 of the inner wall 21 of the housing 20, wherein the retaining ring contact section 111 has a retaining ring contact surface which bears against a downstream second side surface 204 of the radial web 201, and free ends of at least a subset of the plurality of legs 112 are supported under prestress on a support section 24 of the inner wall of the housing 20 extending substantially perpendicular to the flow direction P of the fluid.

[0047] As particularly in the Fig. 1 and 2 illustrated, the plurality of legs 112 extends both in the pre-tensioned state ( Fig. 1 ) as well as in a non-prestressed state ( Fig. 2 ) with respect to the retaining ring abutment portion 111 via an outer bent portion at an obtuse angle radially outward.

[0048] Preference is given to Fig. 3 As illustrated, one or more of the legs 112-1 are shortened or cut off to create the clamping surfaces required for the manufacturing process. The arrangement of the shorter legs 112-1 is chosen such that they are evenly distributed in a circle to avoid an imbalance in the (radial) spring force generated by the (longer) legs 112-2.

[0049] The sealing element 200 further comprises a circumferential sealing lip 205 which extends upstream and towards the inner wall 21 of the housing 20 and whose inner circumferential surface forms a valve seat which defines the valve opening and which is supported by the flap 30 in the Fig. 1 shown closed position of the fluid valve 10 is contacted.

[0050] In this case, a recess 206 is formed between a section of the sealing element 200 having the first radial surface 202 and the sealing lip 205, wherein an upstream end section of the section of the sealing element 200 having the first radial surface 202 tapers radially inward.

[0051] The inner wall 21 of the housing 20 has a widening section 28 adjoining the counter-centering surface 23 upstream, wherein an outer peripheral surface of the sealing lip 205 is spaced from the widening section 28 and lies opposite it.

[0052] The inner wall 21 of the housing 20 further comprises a straight section 29 adjoining the widening section 28 upstream, which extends parallel to the flow direction P of the fluid.

[0053] The sealing element 200 further comprises a downstream, second radial surface 207 adjacent to the radial web 201, which is offset radially inwardly with respect to the first radial surface 202. Preferably, as in Fig. 1 illustrates the first side surface 203 and the second side surface 204 of the radial web 201 formed as a structured surface and / or have at least one annular rib 208.

[0054] The retaining ring 110 has an inner curved portion 113 which is as shown in Fig. 1 illustrated extends substantially in the downstream direction from the retaining ring abutment portion 111, and in particular is opposite the second radial surface 207 of the sealing element 200.

[0055] The inner wall 21 of the housing further comprises a section adjoining the counter-centering surface 23 downstream, which extends radially outward perpendicular to the flow direction P of the fluid and comprises the contact surface 22 against which the first side surface 203 of the radial web 201 rests.

[0056] In addition, the inner wall 21 of the housing has a further section 25 which adjoins the section adjoining the counter-centering surface 23 downstream and which extends parallel to the flow direction P of the fluid, wherein a partial section of the further section 25 is opposite an outwardly facing upper side of the radial web 201 and is spaced therefrom.

[0057] The support section 24 adjoins the further section 25 downstream and extends radially inwards from the further section 25.

[0058] The inner wall 21 of the housing 20 further comprises a further section 26 adjoining the support section 24 downstream, comprising a first section adjoining the support section 24 and extending parallel to the flow direction of the fluid, and a second section adjoining the first section and widening.

[0059] To assemble the fluid valve 10, a housing 20 having a bore is first provided, and the shaft 40 is inserted through the bore into the interior of the housing 20. Then, the flap 30 is inserted into the interior of the housing 20 from the downstream side until the flap 30 touches a flat surface of the shaft 40. In this state, the flap 30 is centered using a tool, which is later also used to center the sealing element 200, with a circumferential centering surface of the tool touching the surface of the inner wall 21 of the housing 20.

[0060] Thereafter, two screws 41 are inserted from the upstream side into the interior of the housing 20, screwed into two screw holes provided in the shaft 40, and tightened after making the necessary adjustments.

[0061] The sealing element 200 is then inserted into the housing 20 and pressed into the designated section of the housing 20, which contains the counter-centering surface 23, until the upstream (structured) first side surface 203 of the radial web 201 rests against the contact surface 22 of the inner wall 21 of the housing 20. In this state, the sealing element 200 is centered in the housing 20.

[0062] The retaining ring 110 is then inserted from the downstream side into the interior of the housing 20 until the retaining ring contact surface rests against the downstream second (structured) side surface 204 of the radial web 201. During assembly, the legs 112 are elastically compressed when the retaining ring 110 is pressed against the radial web 201 of the flexible sealing element 200, which provides sufficient clearance for further insertion of the retaining ring 110 until the free ends of the legs 122 of the retaining ring 110, after passing the support section 24, snap back radially outward due to a spring force of the legs 112 when the retaining ring 110 is pressed with the retaining ring contact surface against the second side surface 204 of the radial web 201 in such a way that the radial web 201 is compressed along the flow direction of the fluid.

[0063] Although exemplary embodiments have been explained in the preceding description, it should be noted that numerous modifications are possible. Furthermore, it should be noted that the exemplary embodiments are merely examples and are not intended to limit the scope of protection, applications, or structure in any way. Rather, the preceding description provides the skilled person with a guide for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as it results from the claims and equivalent combinations of features. List of reference symbols

[0064] 10 Fluid valve 20 Housing 21 Inner wall 22 Contact surface 23 Counter-centering surface 24 Support section 25 Further section 26 Further other section 28 Widening section 29 Straight section 30 Flap 40 Shaft 41 Screw 100 Sealing arrangement 110 Retaining ring 111 Retaining ring contact section 112 Leg 112-1 Short leg 112-2 Long leg 113 Inner curved section 200 Sealing element 201 Radial web 202 First radial surface 203 First side surface 204 Second side surface 205 Sealing lip 206 Recess 207 Second radial surface 208 Annular rib

Claims

1. Sealing arrangement (100) for use in a fluid valve (10) which has a housing (20) and a flap (30) and which is configured to control a fluid flow through a valve opening of the fluid valve (10) by adjusting a position of the flap (30) between a closed position and an open position, wherein the sealing arrangement (100) has a retaining ring (110) with a retaining-ring contact portion (111) and a multiplicity of legs (112), and an annular, flexible sealing element (200) which has an encircling radial web (201) and a first radial surface (202) which is adjacent to the radial web (201), is on the upstream side during use as intended and which is configured to act as a centring surface for an interference fit with a corresponding mating centring surface (23) of an inner wall (21) of the housing (20), wherein a first side surface (203) of the radial web (201) that is on the upstream side during use as intended is provided to lie against a contact surface (22) of the inner wall (21) of the housing (20), the retaining-ring contact portion (111) has a retaining-ring contact surface which, during the use as intended, is provided to lie against a second side surface (204) of the radial web (201) that is on the downstream side during the use as intended, and free ends of at least a partial quantity of the multiplicity of legs (112) are provided, during the use as intended, to be supported under a prestress against a supporting portion (24) of the inner wall of the housing (20), said supporting portion (24) extending substantially perpendicular to the direction of flow of the fluid, characterized in that the sealing element (200) has an encircling sealing lip (205) which, during the use as intended, extends in a direction upstream and in the direction of the inner wall (21) of the housing (20), and the inner circumferential surface of which forms a valve seat which defines the valve opening and which is provided to be contacted by the flap (30) in the closed position of the fluid valve, wherein a recess (206) is formed between a portion of the sealing element (200) that has the first radial surface (202) and the sealing lip (205) so that the sealing element (200) can expand elastically in the direction of the inner wall of the housing during a movement of the fluid valve.

2. Sealing arrangement (100) according to Claim 1, wherein an upstream end portion of the portion of the sealing element (200) that has the first radial surface (202) tapers radially inwards.

3. Sealing arrangement (100) according to Claim 1 or 2, in which the sealing element (200) has a second radial surface (207) which is adjacent to the radial web (201), is on the downstream side during use as intended and which is offset inwards in the radial direction with respect to the first radial surface (202).

4. Sealing arrangement (100) according to one of the preceding claims, in which the multiplicity of legs (112) extend radially outwards via an outer bent portion at an obtuse angle with respect to the retaining-ring contact portion (111).

5. Sealing arrangement (100) according to one of the preceding claims, in which the retaining ring (110) has an inner bent portion (113) which, during the use as intended, extends substantially in a direction downstream from the retaining-ring contact portion (111) and in particular lies opposite the second radial surface (207) of the radial web (201).

6. Sealing arrangement (100) according to one of the preceding claims, in which the first side surface (203) and / or the second side surface (204) of the radial web (201) is formed as a structured surface and / or has at least one annular rib (208).

7. Fluid valve, in particular for a gas line, in particular of a fuel cell and / or a motor vehicle drive, wherein the fluid valve has a housing (20) with an inner wall (21), and has a flap (30) and a sealing arrangement (100) according to one of the preceding claims, wherein the fluid valve is configured to control a fluid flow through a valve opening of the fluid valve (10) by adjusting a position of the flap (30) between a closed position and an open position, wherein the inner wall (21) of the housing (20) has the mating centring surface (23), the contact surface (22) and the supporting portion (24), the first radial surface (202) of the sealing element (200) lies under a prestress against the mating centring surface (23), the first side surface (203) of the radial web (201) lies against the contact surface (22), the retaining-ring contact surface lies against the second side surface (204) of the radial web (201), and free ends of at least a partial quantity of the multiplicity of legs (112) are supported on the supporting portion (24) under a prestress.

8. Fluid valve according to Claim 7, in which the sealing element (200) has the encircling sealing lip (205), the inner wall (21) has an expanding portion adjoining the mating centring surface (23) upstream, and an outer circumferential surface of the sealing lip (205) is spaced apart from the expanding portion and lies opposite the latter.

9. Fluid valve according to Claim 8, in which the inner wall (21) has a rectilinear portion which adjoins the expanding portion upstream and extends parallel to the direction of flow of the fluid.

10. Fluid valve according to Claim 9, in which the inner wall (21) has a portion which adjoins the mating centring surface (23) downstream and which extends radially outwards perpendicular to the direction of flow of the fluid and has the contact surface (22).

11. Fluid valve according to Claim 10, in which the inner wall (21) has a further portion which adjoins the portion, which adjoins the mating centring surface (23), downstream and which extends parallel to the direction of flow of the fluid, wherein a subsection of the further portion lies opposite an outwardly facing upper side of the radial web (201) and is spaced apart from said upper side.

12. Fluid valve according to Claim 11, in which the supporting portion (24) adjoins the further portion downstream, and extends radially inwards from the further portion.

13. Fluid valve according to Claim 12, in which the inner wall (21) has a further, different portion which adjoins the supporting portion (24) downstream and has a first portion, which adjoins the supporting portion (24) and extends parallel to the direction of flow of the fluid, and a second portion which adjoins the first portion and expands.

14. Fuel cell arrangement, in particular for a motor vehicle drive, with at least one fuel cell, at least one gas line, in particular for supplying gas to, and discharging gas from, the fuel cell, and a fluid valve according to one of the Claims 7-13 for blocking the gas line by adjusting the flap (30) into the closed position.

15. Motor vehicle with at least one fluid valve according to one of the Claims 7-13, in particular for blocking a line, in particular gas line, of the motor vehicle, in particular a motor vehicle drive line and / or fuel cell arrangement line, by adjusting the flap (30) into the closed position.

16. Method for mounting a fluid valve according to one of the Claims 7-13, having the steps of: providing the housing (20) having a bore, inserting a shaft (40) through the bore, introducing the flap (30) from a downstream side of the housing (20) and mounting the flap (30) on the shaft (40), introducing the sealing element (200) from the downstream side of the housing (20) in such a manner that the first side surface (203) of the radial web (201) lies against the contact surface (22) of the inner wall (21) of the housing (20), and the first radial surface (202) lies against the mating centring surface (23) of the inner wall (21) of the housing, and introducing the retaining ring (110) from the downstream side of the housing (20) in such a manner that the free ends of the at least partial quantity of the multiplicity of legs (112) are bent radially inwards elastically during the insertion by contact with the inner wall (21) of the housing (20) and, after passing the supporting portion (24), snap back radially outwards by a spring force of the legs (112) when the retaining ring (110) is pressed with the retaining-ring contact surface against the second side surface (204) of the radial web (201) in such a manner that the radial web (201) is compressed along the direction of flow of the fluid.