Receptacle for a fluid plug-in coupling and fluid plug-in coupling with such a receptacle

Abstract

The invention relates to a receiving part (2) for a fluid plug-in coupling (1) with a socket part (4) which has a receiving opening (5) for a plug part (3) which can be inserted into the socket part (4) in an axial insertion direction (S), and with an expandable holding part (6) by means of which the plug part (3) can be locked in a latching manner via a holding step (3a) of the plug part (3) to prevent it from being released from the socket part (4), wherein the holding part (6) has at least one radially spring-elastically expandable holding arm (7) for engaging behind the holding step (3a) of the plug part (3).In order to achieve greater strength with simplified production of the receiving part and with a simple possibility of producing and removing the plug-in connection, it is proposed that the holding part (6) engages over the socket part (4) at the end face with an annular head region (8), wherein the holding part (6) has at least one snap arm (10) located in an outer casing region (9), protrudes axially from the head region (8) in the direction of the socket part (4), can be expanded radially in a resilient manner and is for engaging behind a locking step (12) located on the outer circumference (11) of the socket part (4), which snap arm is concentric with the holding arm (7) which can be expanded radially in a resilient manner and is for engaging behind the holding step (3a) of the plug part (3), which is arranged in an inner casing region (13) of the holding part (6).

Description

[0001] The present invention relates to a receiving part for a fluid plug-in coupling with a socket part, which has a receiving opening for a plug part that can be inserted into the socket part in an axial insertion direction, and with an expandable holding part, by means of which the plug part can be locked against detachment from the socket part via a holding step of the plug part, wherein the holding part has at least one radially elastically expandable holding arm for engaging behind the holding step of the plug part in a locking manner, wherein the holding part further engages over the socket part with an annular head region on the front side, wherein the holding part has at least one radially elastically expandable snap arm located in an outer casing region, projecting axially from the head region in the direction of the socket part, for engaging behind a locking step located on the outer circumference of the socket part,which is concentric with the radially resiliently expandable holding arm for engaging behind the holding step of the plug part, which is arranged in an inner casing area of ​​the holding part.

[0002] Furthermore, the invention relates to a fluid plug-in coupling with a plug part and with such a receiving part.

[0003] A receiving part of the type mentioned is particularly suitable for connection to a plug part in a standard design, with a so-called SAE plug, which is designed in the form of a pipe section which has an annular shoulder on its outer circumference to form a radial holding step. The connection contours are preferably designed according to the SAE J2044 standard (August 2009 edition). The connection is initially made by simply axially plugging together the receiving part and plug part, which is also referred to as a "male connection". The receiving part is also referred to as a "female connection". After plugging together the receiving part and plug part, the holding part of the receiving part engages behind the annular shoulder of the plug part, and then after axially retracting the plug part relative to the receiving part orThe final connection is made by manually pressing the female part against the male part, with the retaining part acting as a locking element. The retaining part, mounted in the socket part, thus serves to releasably secure the inserted male part, with radially elastically deformable - expandable - retaining sections for engaging behind the retaining step of the male part.

[0004] DE 39 24 173 A1 discloses a connection fitting for pipes, comprising a connecting element having a receiving bore for a pipe end provided with a fastening bead and a sealing ring encompassing the pipe end. A retaining element, which can be detachably connected to the connecting element and by means of which the pipe end can be fastened in the receiving bore, engages the fastening bead, similar to that present in the aforementioned SAE connector. The retaining element consists of a bushing which can be pushed onto the pipe end and inserted into the receiving bore together with the latter. The bushing has a region which is elastically deformable in the radial direction and which is provided in its bore with a groove which can be latched over the fastening bead of the pipe end and which forms a locking mechanism which engages in a groove in the connecting element.The bushing consists of a cylindrical, unslotted section whose bore diameter is adapted to the outer diameter of the pipe end. The outer diameter of the section is adapted to the inner diameter of a step of the connecting element. Adjacent to this section is an elastically deformable area which is divided into spring tongues by several equally spaced, longitudinally extending slots. These spring tongues are elastically deformable, primarily in the radial direction. The bore diameter remains unchanged up to approximately the middle of the spring tongues and then transitions into a bore area which widens conically towards the outside.

[0005] Preferably, the socket part mentioned above also contains a sealing arrangement for circumferentially sealing the inserted plug part, which can comprise one or more annular seals. Particularly preferably, the sealing arrangement consists of two sealing rings with a spacer ring arranged between them. In a design of a receiving part known from DE 202 01 574 U1, similar to the type mentioned above, the receiving part also comprises an additional release element, which is mounted externally on the socket part.

[0006] A receiving part of the type mentioned is particularly suitable for use with plugs and in plastic couplings for fuel lines and for so-called SCR lines. SCR is an abbreviation for Selective Catalytic Reduction, which means that the lines carry a fluid for a chemical reaction taking place in an SCR catalyst, which reaction proceeds selectively. Nitrogen oxides such as nitrogen monoxide and dioxide are preferentially reduced in the catalyst, while undesirable side reactions such as the oxidation of sulfur dioxide to sulfur trioxide are largely suppressed. SCR lines are in particular heatable fluid lines, which are known in various forms and are used, for example, in fluid distribution systems in motor vehicles.The fluid is then in particular an aqueous urea solution, which is used to reduce nitrogen oxides in exhaust gas catalysts and is known under the brand name “AdBlue”.

[0007] At low ambient temperatures, such a fluid can freeze. For this reason, the fluid-carrying elements, such as pumps or media lines, or even the couplings, are heated to prevent freezing or to thaw an already frozen fluid. The amount of fluid to be thawed naturally influences the time required to restore operational readiness. This results in, among other things, the requirement for fluid plug-in couplings with a receiving part of the type mentioned above - and especially for the receiving part itself - to have a low freezing volume, i.e. to minimize the volume of fluid contained in the receiving part when flowing through it and also when at rest. The same applies, for example, if the fluid is water for a windshield washer system.

[0008] In addition, the stress conditions during operation give rise to further requirements, particularly those relating to the possible occurrence of high temperatures, which at certain points in the system or lines can range from 140 °C to 180 °C, and briefly even up to 200 °C. High absolute pressures can also occur, which are normally in the range from 5 bar to 10 bar, and in some cases up to 15 bar. Finally, pressure pulsations may need to be compensated for, and it must be taken into account that, for example, the freezing and thawing of the fluid mentioned above is associated with volume changes. In view of the stress magnitude, this is also referred to as ice pressure resistance. The preferred applications of the female part, however, are fluid plug-in couplings in low-pressure applications, so the female part is preferably made of plastic.

[0009] A receiving part similar to the type mentioned above is also known from DE 197 35 491 C1. This document describes a plug-in coupling for connecting two fluid lines. In this coupling, one fluid line has at least one retaining rib. The known plug-in coupling comprises a sleeve having radial openings and a cylindrical locking device guided axially displaceably in the sleeve, which has axially extending and elastically flexible retaining arms with a hook formed at the free end for engaging behind the retaining rib of the fluid line axially inserted into the locking device. The hooks have a radially outer inclined surface at their free end, which, when the sleeve and locking device are moved apart, is pressed against a front edge of an opening in the sleeve that axially displaceably receives the radially outer part of the hook, so that the respective hook remains correspondingly more firmly engaged with the retaining rib.In addition, the hooks have a radially inner inclined surface that comes into contact with the holding rib when the locking device and the inserted fluid line are pulled apart, so that the holding arms are spread and enable uncoupling. At least one sealing ring is arranged between an inner shoulder of the sleeve and the locking device, wherein the locking device has a release arm between each of the holding arms, which projects axially displaceably outwards through one of the openings. On the inside, the sleeve has axially extending ribs between the holding arms and the release arms of the locking device, which rest against the holding rib of the fluid line inserted into the locking device through an insertion opening in the sleeve.

[0010] A further development of this is a connecting element as described in EP 2 439 439 A2. The connecting element has an insertion area into which a plug can be axially inserted, wherein the housing has a locking element with which the plug can be locked. Furthermore, a safety element is provided, wherein the locking element can be moved axially relative to the housing between a first position and a second position by a pulling movement between the housing and the locking element, wherein the locking element, in the second position, releases at least one space that can be filled by the safety element.

[0011] Finally, DE 696 21 292 T2 (EP 0 756 125 B1) discloses a pipe connection comprising a connecting body with a passage open at one end of the body to receive a pipe. The pipe connection comprises a sleeve arranged in the passage, an annular element, and at least one radially resilient finger extending from the element in an axial direction towards the open end of the passage. The connecting body has a stop surface directed away from the open end along the passage axis. The distal end of the finger has a projection on its inner side for interacting with an element on the pipe and a first, axially machined stop on its outer side, directed towards the open end of the passage to interact with the stop surface.In addition, the distal end of the finger has a further radially directed stop which can cooperate with the connecting body when the axially directed stop cooperates with the stop surface to prevent the distal end of the finger from moving radially outward and thereby prevent detachment of the projection on the finger from the element of the tube and detachment of the tube from the connecting body.In this case, it is provided that the sleeve has an extension sleeve which projects on the annular element of the sleeve through the open end of the connecting body, wherein the sleeve has an opening in which at least one resilient sleeve finger is provided, and wherein the sleeve is provided outside the connecting body with an annular head which lies over the end of the connecting body around the open end of the passage and which can be pressed onto the end of the connecting body in order to release the first stop of the at least one sleeve finger from the stop surface on the connecting body.

[0012] DE 196 19 026 A1 discloses a quick-action coupling, particularly for refrigerant lines, which comprises a sleeve and a nipple insertable therein, and which further comprises a locking device for the coupled position between the sleeve and nipple. This locking device has a bead on the nipple, which projects radially outwards, and a cage mounted in the sleeve with expandable retaining fingers that grip behind the bead. An indicator device is provided which has an axially extending arm, which can be displaced radially outwards, the end of which is visible and / or palpable from the outside in the coupled position. Due to the cage that must also be mounted in the sleeve, the design and assembly effort required to create the coupling connection appears to be high.

[0013] From US 4 948 180 A a connector for a small diameter pipe having opposite first and second ends is known, the pipe further comprising an outwardly curved annular portion near the first end of the pipe, the connector comprising: - a body forming a generally tubular wall with opposite front and rear axial ends, - an axially extending communication hole formed in the front axial end of the tubular wall, - a large stepped chamber formed in the rear axial end of the tubular wall of the body and communicating with the communication hole at the front end of the body, the chamber being dimensioned to accommodate the outwardly curved annular portion of the tube, - a jaw wall projecting outwards from the rear end of the tubular wall, - and annular sealing means mounted in the chamber to provide a seal between the tube and the body, the sealing means having a central opening for receiving the first end of the tube and being dimensioned to abut the outwardly curved annular portion of the tube spaced from the first end thereof; - at least one bushing element for engaging a side of the outwardly curved annular portion of the tube facing the second end of the tube and thereby retaining the first end of the tube in the bushing, the bushing element comprising a base mounted on the rear axial end of the body, - and at least one resilient claw wall having a front end projecting forwardly from the base of the socket member such that the front end of the resilient claw wall projects into the chamber of the body, the length of the claw wall being selected such that its front end engages the outwardly curved annular portion of the tube and holds the outwardly curved annular portion of the tube against the annular sealing means; - and a retaining element comprising an annular wall engaging a surface of the base of the socket element opposite the body, and a plurality of axially extending claw walls extending axially over the outer periphery of the socket element and the jaw wall of the base, each engaging claw wall comprising a front end portion bent radially inwardly for engagement with the jaw wall, with a forward-facing portion for retaining the socket element against the rear axial end of the body. This known connector is largely similar to a female part of the type mentioned above, but with a difference in the construction of the respective retaining parts.Thus, the holding arm for the plug part according to the type mentioned at the beginning is arranged exactly opposite to the claw walls (“plurality of claw walls”) known from US 4 948 180 A, so that in the prior art there is no locking “engagement behind” of a holding arm for the holding step of the plug part, but only a - less stable - “facing” is realized, which reduces the strength of the plug connection.

[0014] The aforementioned known receiving parts are in need of improvement from various perspectives, in particular, for example, from the aspects that the receiving part known from DE 202 01 574 U1 and that from DE 696 21 292 T2 (EP 0 756 125 B1) is each constructed in several parts, at least three parts, and that the majority of the known receiving parts each have openings in their socket part. The known receiving parts also have comparatively large freezing volumes.

[0015] This leads to the object underlying the present invention, namely to provide a receiving part of the type mentioned above and a fluid plug-in coupling with such a receiving part, which have greater strength while simplifying the production of the receiving part and allowing for simpler creation and removal of the plug-in connection. Furthermore, the receiving part according to the invention should preferably be characterized by a comparatively more compact design, i.e., an axially shortened installation space, and thus by a smaller freezing volume compared to the prior art, as well as the possibility of integrating an anti-rotation device.

[0016] According to the invention, the object underlying the present invention is achieved according to claim 1 by a holding part of the type mentioned at the outset, in which outer holding and guiding segments which can be expanded in a particularly radially resilient manner are located between the snap arms in the outer casing region as seen in the circumferential direction. The outer holding and guiding segments located in the outer casing area, which can be expanded radially between the snap arms, particularly in a spring-elastic manner, can advantageously be connected to the inner holding and guiding segments in the inner casing area through the head area to form a longitudinally C-shaped clamp for the socket part, in which the socket part can be axially guided and held. In a similar manner—but without a radial connection between the parts—the socket part can also be guided between an outer holding and guiding segment and a holding arm for the plug part.

[0017] A fundamental advantage of the invention is that, due to the snap-in arms engaging on the outside of the socket part, no openings are necessary in the socket part, thus providing greater strength. The plug-in system represented by the fluid plug-in coupling according to the invention thus has a higher mechanical load capacity than known systems and is, in particular, better protected against failure of the receiving part. In the case of SCR lines, this also advantageously improves heatability, since the externally closed receiving part according to the invention can be easily equipped with a heating cable.

[0018] Furthermore, the invention advantageously reduces the number of components, and by avoiding perforations, the haptic properties important for plugging and unplugging the receiving part according to the invention can be improved. Furthermore, the components of the fluid plug-in coupling according to the invention, in particular the receiving part according to the invention, are advantageously easily scalable, particularly in the range of 1 / 4" - 3 / 8", but also beyond these range limits. This means that, in particular, a scale transfer to other standardized connector sizes is easily possible without restricting functionality.

[0019] Finally, the inventive design of the receiving part allows for the integration of further advantageous structural details, such as a release lock, into the receiving part. Further advantageous design features of the invention are contained in the subclaims and the following description.

[0020] The invention will be explained in more detail below using preferred embodiments. In the following: Fig. 1 in a perspective exploded view, a first preferred embodiment of a fluid plug-in coupling according to the invention with a receiving part according to the invention, Fig. 2 a perspective view of the Fig. 1 illustrated fluid plug-in coupling according to the invention with the receiving part according to the invention, Fig. 3 an axial longitudinal section through the Fig. 2 shows a fluid plug-in coupling according to the invention with the receiving part according to the invention, Fig. 3a a greatly enlarged view of the Fig. 3 detail marked IIIA, Fig. 4 a sectional view as in Fig. 3, but with a plug part which is not connected to the receptacle part according to the invention, Fig. 5 a greatly enlarged axial longitudinal section through the holding part of a receiving part according to the invention of the first embodiment, Fig. 6 and Fig. 7 perspective views of the Fig. 5 shown holding part of a receiving part according to the invention from different angles, Fig. 8 an enlarged sectional view of the Fig. 4 shown receiving part according to the invention, but in a different assembly phase, Fig. 9 a greatly enlarged axial longitudinal section through the socket part of a receiving part according to the invention of the first embodiment, in a representation similar to that in Fig. 5 for the holding part, Fig. 10 the socket part of a receiving part according to the invention of the first embodiment in a perspective view, similar to that in Fig. 2 for the fluid plug-in coupling according to the invention, Fig. 11 a greatly enlarged axial longitudinal section through a fluid plug-in coupling according to the invention in its first preferred embodiment with the receiving part according to the invention in an intermediate state of assembly, Fig. 12 similar to Fig. 1, in a perspective exploded view, a second preferred embodiment of a fluid plug-in coupling according to the invention, but only the receiving part according to the invention is shown, Fig. 13 a side view of the holding part of a receiving part according to the invention of the second preferred embodiment of a fluid plug-in coupling according to the invention, Fig. 14 in a representation similar to Fig. 5, a longitudinal section through the Fig. 13 shown holding part, Fig. 15 and Fig. 16 in representations similar to Fig. 6 and Fig. 7, two partially sectioned perspective views of the Fig. 13 shown holding part from different angles, Fig. 17 in a representation similar to Fig. 9, an enlarged axial longitudinal section through the socket part of a receiving part according to the invention of the second embodiment, Fig. 18 in a representation similar to Fig. 10, the socket part of a receiving part according to the invention of the second embodiment in perspective view, Fig. 19 in perspective view, a secondary locking part characteristic of the second embodiment, in a view from below, ie seen opposite to the plugging direction, Fig. 20 a longitudinal section through the Fig. 19 shown secondary locking part, Fig. 21 a plan view from the axial direction of the Fig. 12 shows the receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention in assembly, with the secondary locking part in the unlocked position, Fig. 22 a side view of the Fig. 21 of the second preferred embodiment of a fluid plug-in coupling according to the invention, wherein the secondary locking part is in the unlocked position, Fig. 23 in a representation similar to Fig. 4, but without the plug part and rotated by 180°, an axial longitudinal section through the Fig. 21 and Fig. 22 shown receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention (section XXIII-XXIII in Fig. 21), Fig. 24 a cross-section through the Fig. 21 to 23 shown receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention in a sectional plane XXIV-XXIV according to Fig. 22, Fig. 25 in a sectional view as in Fig. 23, which is Fig. 21 to 24 shown receiving part at the beginning of the insertion process of a plug part, Fig. 26 in a sectional view as in Fig. 23 and Fig. 25, which is Fig. 21 to 25 shown receiving part at the end of the insertion process of a plug part, Fig. 27 a sectional view of the receiving part as in Fig. 24, but at the end of the insertion process of a plug part according to Fig. 26, Fig. 28 a cross section through the Fig. 21 to 27 shown receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention at the end of the insertion process of a plug part corresponding Fig. 26, in a section plane XXIII-XXIII according to Fig. 22, Fig. 29 a side view of a receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention as in Fig. 21, at the end of the insertion process of a plug part (not shown) according to Fig. 26, wherein the secondary locking part is in the locked position, Fig. 30 in one Fig. 27 corresponding representation (section plane XXIV-XXIV in Fig. 22 or section plane XXX-XXX in Fig. 29) a section through the receiving part at the end of the insertion process of a plug part according to Fig. 26, but the secondary locking part is arranged as in Fig. 29 is in the locked position, Fig. 31 in a Fig. 28 corresponding representation (section plane XXVIII-XXVIII in Fig. 22 or section plane XXXI-XXXI in Fig. 29), a section through the receiving part at the end of the insertion process of a plug part according to Fig. 26, but the secondary locking part is arranged as in Fig. 29 and Fig. 30 is in the locked position, Fig. 32 a plan view of the receiving part of the second preferred embodiment of a fluid plug-in coupling according to the invention as in Fig. 21, but with the plug part inserted and the secondary locking part locked, as shown in 29 to 31, Fig. 33 a detailed view from a longitudinal section in the section plane XXXIII-XXXIII in Fig. 32 (corresponding to section plane XXIII-XXIII in Fig. 21), Fig. 34 a sectional view of the receiving part according to the section plane XXXIV-XXXIV in Fig. 29, but the secondary locking part is again as in Fig. 21 is in the unlocked position, Fig. 35 a third preferred embodiment of a receiving part of a fluid plug-in coupling according to the invention in a representation similar to that in Fig. 21, but rotated by 45°.

[0021] With regard to the following description, it is expressly emphasized that the invention is not limited to the exemplary embodiments, nor to all or several features of the feature combinations described in a particular exemplary embodiment. Rather, each individual partial feature of the exemplary embodiments may have inventive significance, both independently of all other partial features described in connection therewith and in combination with any features of the other exemplary embodiment.

[0022] In the figures of the drawing, the same and corresponding parts are always provided with the same reference symbols, so that they are usually described only once.

[0023] As initially appears from Fig. 1 to 4, which show a fluid plug-in coupling 1 according to the invention with a receiving part 2 according to the invention, the receiving part 2 according to the invention has a socket part 4 with a receiving opening 5 for a plug part 3 that can be inserted into the socket part 4 in an axial insertion direction S running along the longitudinal axis XX. In addition, the receiving part 2 has an expandable holding part 6, by means of which the plug part 3 can be locked in a latching manner via a holding step 3a located thereon to prevent it from becoming detached from the socket part 4. The holding part 6 has radially spring-elastically expandable holding arms 7 for engaging behind the holding step 3a of the plug part 3 in a latching manner.

[0024] As in particular Fig. 2 to 4 illustrate, in the assembled state the holding part 6 engages over the sleeve part 4 at its end face 4a with a head region 8 which is basically designed as a closed ring, wherein the holding part 6 has snap arms 10 which are located in an outer casing region 9 and project axially from the head region 8 in the direction of the sleeve part 4 and can be spread radially in a spring-elastic manner for engaging behind a locking step 12 located on the outer circumference 11 of the sleeve part 4.

[0025] These radially resiliently expandable snap arms 10 for engaging behind the locking step 12 located on the outer circumference 11 of the socket part 4 are arranged concentrically with the radially resiliently expandable holding arms 7 for engaging behind the holding step 3a of the plug part 3 with respect to the longitudinal axis XX. The latter, in turn, are located in an inner jacket region 13 of the holding part 6. The inner jacket region 13 and the outer jacket region 9 are connected to one another by the head region 8 of the holding part 6.

[0026] Both the sleeve part 4 and the holding part 6 can be manufactured in a simple manner, e.g., as one-piece plastic injection-molded parts, preferably using rotary cores.

[0027] The mounting of the receiving part 2 can be achieved by simply sliding the holding part 6 onto the socket part 4 in an axially extending plug-in direction S while spreading its snap arms 10. This can be considered a pre-assembly step with regard to the overall production of the fluid plug-in coupling 1 according to the invention. Final assembly then involves the axial insertion of the plug part 3 into the pre-assembled receiving part 2 in the same plug-in direction S as previously used for the holding part 6.

[0028] At least one holding arm 7 and one snap arm 10 should be present. In the preferred embodiment of the invention, three holding arms 7 offset by 120° from one another and three snap arms 10 offset by 120° from one another are provided on the holding part 6 according to the invention, wherein the holding arms 7 are located circumferentially centrally between the snap arms 10, i.e. the holding arms 7 in the inner casing region 13 and the snap arms 10 in the outer casing region 9 are arranged alternately with a mutual angular offset of 60°. This is particularly clear from Fig. 1 and Fig. 2 and from the individual representations of the holding part 6 in Fig. 6 and Fig. 7. Such a design ensures both a simple possibility of establishing and re-establishing a secure plug connection between plug part 3 and receptacle part 2, as well as a simple possibility of establishing and re-establishing a secure plug connection between the two parts of the receptacle part 2 - sleeve part 4 and holding part 6.

[0029] The start of the pre-assembly of the receiving part 2 according to the invention, i.e. the start of the assembly of the sleeve part 4 and the holding part 6, is in Fig. 8, while the final state after pre-assembly is shown in particular by the sectional views in Fig. 3 and Fig. 4. The design of the snap arms 10 can be seen in the lower half of the figure.

[0030] The snap arms 10 each have a locking hook 10a with a radially inwardly directed tip for engaging behind the locking step 12 located on the outer circumference 11 of the sleeve part 4, which can in particular - as shown - be a locking edge formed by a diameter step of the outer contour of the sleeve part 4, which is cylindrical in this area from the basic shape.

[0031] The tip of the locking hooks 10a of the snap arms 10 is characterized in that an inclined surface 10b diverging in the plug-in direction S is formed on the locking hooks 10a, which at the beginning of the pre-assembly interacts with the sleeve part 4, in particular with a complementary inclined surface 4b located radially outward on its end face 4a, which also diverges in the plug-in direction S. When the inclined surface 10b of the locking hook 10a and the inclined surface 4b of the sleeve part 4 slide onto one another as a result of plugging in the plug-in direction S, the snap arms 10 are spread apart radially in a resilient manner by the wedge effect until, after axially passing over the locking step 12, they snap radially inwards in a resilient manner and engage behind the locking step 12 and thus hold the sleeve part 4 and the holding part 6 together.

[0032] The Fig. The greatly enlarged illustration shown in Figure 3a of the locking connection formed by the locking step 12 and the locking hook 10a between the holding part 6 and the sleeve part 4 illustrates that an inclined surface 12a diverging in the plug-in direction S can be provided on the locking step 12, just as such an inclined surface 10c diverging in the plug-in direction S can be formed in a complementary manner on the locking hook 10a of the snap arm 10. Wedging of these two surfaces 10c, 12a causes mutual bracing of the holding part 6 and the sleeve part 4 under axial load and thus self-reinforcement of the locking connection or self-locking of the connection against unintentional release.

[0033] Preferably, before the socket part 4 and the holding part 6 are plugged together, a sealing arrangement 14 for circumferentially sealing the inserted plug part 3 can be introduced into the receiving opening 5 of the socket part 4 in a manner known per se. Such a sealing arrangement 14 is only required for the first embodiment of the invention in Fig. 1 and Fig. 11. In a preferred embodiment, it may comprise one or more annular seals 15, with a sealing arrangement 14 consisting of two sealing rings 15 with a spacer ring 16 arranged between them being particularly preferred.

[0034] In contrast to the known prior art, the sealing arrangement 14 can advantageously be fixed by the holding part 6 in the axial direction XX against movement counter to the plug-in direction S. For this purpose, a foot region 17 of the inner casing region 13 of the holding part 6, which foot region is axially diametrically opposite the head region 8 of the holding part 6, can be designed as a closed ring, from which the resiliently expandable holding arms 7 protrude axially counter to the plug-in direction S for engaging behind the holding step 3a of the plug part 3. This design is achieved in particular by Fig. 6 illustrates.

[0035] The sealing arrangement 14 can be fixed against movement in the plug-in direction S, for example, by - as Fig. 3, Fig. 4 and Fig. 8 show - a circumferentially surrounding inner holding shoulder 18 is provided in the receiving opening 5 of the sleeve part 4.

[0036] The snap arms 10 for the socket part 4 in the outer casing region 9 of the holding part 6, which protrude axially from the head region 8 in the plug-in direction S and can be expanded radially with elasticity, and the holding arms 7 for the plug part 3 in the inner casing region 13 of the holding part 6, which protrude radially with elasticity and can be expanded radially with elasticity, and which protrude from the foot region 17 against the plug-in direction S, are formed in a preferred embodiment by slots in the outer casing region 9 and in the inner casing region 13. The slots in the outer casing region 9 are open on the side facing the socket part 4 and end in the head region 8. They are each designated by the reference numeral 19, while the slots in the inner casing region 9 are open on the side facing away from the socket part 4, end in the foot region 17 and are each designated by the reference numeral 20. The slots 19, 20 are shown in the perspective views of the holding part in Fig. 1, Fig. 2, Fig. 6 and Fig. 7, and particularly good at Fig. 6. They advantageously ensure the deformability of the holding arms 7 and the snap arms 10 in particular, but also of the outer holding and guide segments 21 described below.

[0037] The slots 19, 20 bring about a circumferential segmentation of the holding part 6 of the receiving part 2 according to the invention into six outer segments 10, 21 in the outer casing region 9 and into six inner segments 7, 22 in the inner casing region 13, which is advantageous with regard to high functionality of the receiving part 2 according to the invention. Two circumferentially opposite slots 19 in the outer casing region 9 are preferably each located in a plane of a radial longitudinal section through the holding part 6, in which plane two circumferentially opposite slots 20 are also located in the inner casing region 13. Each segment 10, 21 in the outer casing region 9 is thus assigned a segment 22, 7 in the inner casing region 13, ie it is located opposite it - viewed in the radial direction.

[0038] Three of the outer segments in the outer jacket area 9 are formed by the snap arms 10 for the socket part 4. Three of the inner segments in the inner jacket area 13 are formed by the holding arms 7 for the plug part 3. The fact that a slot 19 runs through the outer jacket and a slot 20 through the inner jacket at a regular angular offset of 60° enables - as already mentioned - the holding arms 7 and the snap arms 10 to be arranged alternately with a mutual angular offset of 60°.

[0039] What has not been mentioned so far is the type of segments 21 that are located in the outer casing area 9 opposite the holding arm segments 7 in the inner casing area 13, and the type of segments 22 that are located in the inner casing area 13 opposite the snap-arm segments 10 in the outer casing area 9. These segments 21, 22 are outer holding and guiding segments 21 and inner holding and guiding segments 22 for the socket part 4. As the sectional views in Fig. 3 and Fig. 4, an inner holding and guiding segment 22 in the inner casing region 13 forms, with the snap-arm segment 10 opposite it in the outer casing region 9 - connected by the head region 8 - a clamp for the socket part 4, which is C-shaped in longitudinal section and in which the latter can be axially guided and held. In a similar way - but without a radial connection between the parts 7, 21 - the socket part 4 is also guided between an outer holding and guiding segment 21 and a holding arm 7 for the plug part 3. For the purpose of optimal sliding guidance, a clearance or transition fit can preferably be provided between the adjoining parts. The inner holding and guiding segments 22 in the inner casing region 13, together with the holding arm segments 7 arranged alternately between them, also serve to axially guide the plug part 3 during its assembly and disassembly.

[0040] The outer holding and guiding segments 21, which are located circumferentially between the snap-arm segments 10 in the outer casing area 9, are shorter in the embodiment shown than the snap-arm segments 10. In this context, particular reference is also made to Fig. 3 and Fig. 4, which show a further advantageous feature of the invention. The drawing shows that the outer holding and guiding segments 21, which are basically designed as walls of a hollow cylinder, in the assembled state bear in a form-fitting manner against the casing 4c of the sleeve part 4, which is also basically hollow-cylindrical. On the casing 4c there is a circumferentially extending inclined surface 4d which diverges in the plug-in direction S. When the holding part 6 is plugged onto the sleeve part 4, this inclined surface 4d initially causes a radial deflection of the outer holding and guiding segment 21, which - like the snap arms 10 - can also be expanded elastically.As soon as the holding part 6 is released after being plugged in, this spring elasticity causes a radial reset of the outer holding and guide segment 21 and, through the interaction with the inclined surface 4d, an automatic axial return displacement of the holding part 6 against the plug-in direction S into a position in which the outer snap arms 10 located between the guide segments 21 rest with their locking hooks 10a on the locking step 12. An axial over-plugging of the locking element 6 is thus prevented or automatically compensated for immediately. This, among other things, demonstrates the advantageously increased ease of use of a fluid plug-in coupling 1 according to the invention. In the depressurized state of the system, the inclined surface 4d prevents the receiving part 2 according to the invention from opening spontaneously by the holding part 6 unintentionally separating from the socket part 4.

[0041] As can be seen particularly from the individual parts of the socket part 4 in Fig. 9 and Fig. 10, the sleeve part 4 is also segmented on its side facing the holding part 6. This segmentation comprises at least one holding claw 23, preferably - as shown - three holding claws 23 with three circumferential recesses in between. For the sake of clarity, the latter are only shown in Fig. 9 and Fig. 10 is marked with the reference number 24.

[0042] The locking of the socket part 4 with the holding part 6 takes place in the circumferential area of ​​the recesses 24. There lies a surface portion of the end face 4a, from which the already mentioned inclined surfaces 4b diverging in the plug-in direction S originate. Another surface portion of the end face 4a is formed by the cover surfaces of the holding claws 23. Since the holding claws 23 are intended to interact with the holding arms 7 of the holding part 6 for the plug part in the manner described below, the number and arrangement of the holding claws 23 corresponds to that of the holding arms 7 of the holding part 6 for the plug part 3. In the embodiment shown, therefore, three holding claws 23 are provided, offset from one another by 120°.Since the locking of the sleeve part 4 with the holding part 6 takes place via the snap arms 10 in the circumferential area of ​​the recesses 24, and since the snap arms 10 are offset by 60° in relation to the holding arms 7 of the holding part 6, after the pre-assembly of the sleeve part 4 and holding part 6 the holding arms 7 of the holding part 6 come to lie in radial proximity to the holding claws 23 of the sleeve part 4, as shown. Fig. 3, Fig. 4, Fig. 8 and Fig. Show 11.

[0043] Here, after the pre-assembly of socket part 4 and holding part 6 - thus excluding the Fig. 8 - two possible basic positions can be distinguished. On the one hand, this is the basic position, which is Fig. 3 and Fig. 4. This represents a locking position for the holding arms 7. On the other hand, this is the basic position, which in Fig. 11. This represents a release position for the holding arms 7.

[0044] To lock and release the radially spring-elastic spreading movement of the holding arms 7, the holding claws 23 have lugs 23a with radially inward-facing tips, which are designed similarly to the locking hooks 10a of the snap arms 10. In the locked position, the lugs 23a come into contact with the radially outward-facing side of the holding arms 7 and block their possible outward movement, which is necessary to assemble or disassemble the plug part 3. In the locked position, the holding arms 7 can exert a radially acting force on the lugs 23a. In addition, friction creates a blocking effect against displacement of the holding part 6 in the plug-in direction S.

[0045] In the locking position, the holding arms 7 are located on the one hand after the pre-assembly of the receiving part 2 according to the invention and before the assembly of the plug part 3 ( Fig. 4), as well as after mounting the plug part 3 ( Fig. 4), that is, when the final assembly of the fluid plug-in coupling 1 according to the invention has been completed. The locking position is in the corresponding Fig. 3 and Fig. 4 each marked by a circle and the word “LOCKED”.

[0046] The Fig. The release position for the holding arms 7 shown in Figure 11, which is characterized in that the holding arms 7 are displaced in the axial plugging direction S under the lugs 23a, is assumed during assembly and disassembly of the plug part 3. This is shown in Fig. 11 is marked by a circle and the word "RELEASE". However, in order for the retaining arms 7 to be displaced in the axial insertion direction S, i.e., so that the retaining part 6 and the sleeve part 4 can be compressed axially more strongly than in the locking position, a possible play in the axial direction XX must be provided at various points between some components.

[0047] This necessary axial play is - designated by the reference symbol A - in Fig. 3. It must exist in the receiving opening 5 of the socket part 4 between the tip 3b of the plug part 3 and a bottom 25 of the socket part 4, and also there between the Fig. 3 not shown sealing arrangement 14, for which, however, a boundary line is drawn, and the holding shoulder 18 for this sealing arrangement 14, and on the other hand between the inner holding and guide segment 22 and a circumferential inner shoulder 26 of the sleeve part 4, which forms an axial stop for the holding part 6 when the holding part 6 is axially inserted into the sleeve part 4, as is also shown in Fig. 11 and is specifically marked there by a circle. Finally, the axial clearance A should also be present between the end face 4a of the sleeve part 4 in the area of ​​its respective end-face recess 24 and the underside of the head region 8 facing the sleeve part 4 in the area of ​​the snap arms 10.

[0048] The axial play A can advantageously be chosen very small according to the invention. For example, Fig. 3 shows that the axial play in the receiving opening 5 of the socket part 4 between the tip 3b of the plug part 3 and the base 25 of the socket part 4 is also minimal because the shape of the base 25 in the receiving opening 5 of the socket part 4 is adapted to the shape of the tip 3b of the plug part 3. This creates an optimally small freezing volume in this area.

[0049] During assembly of the fluid plug-in coupling 1 according to the invention, the receiving part 2 comes out of the Fig. 4 by inserting the plug part 3 into the release position. For this purpose, the plug part 3 is moved in the insertion direction S against the receiving part 2 until its holding step 3a, a ring projection located on its outer circumference, comes into contact with a first inclined surface 7a of the holding arms 7 of the holding part 6, which converges in the insertion direction S. This should lead to a radial spreading of the holding arms 7, but this is prevented precisely by the radial outer stop of the holding arms 7 on the lugs 23a of the holding claws 23. As the plug part 3 is inserted further, it therefore takes the holding part 6 with it in the insertion direction S and presses it deeper into the socket part 4. This is possible due to the presence of the described axial play A. As a result, the receiving part 2 moves into the release position for the holding arms 7. Fig. However, Figure 8 does not show the release during assembly of the fluid plug-in coupling 1 according to the invention, but rather during its disassembly, which can be seen from the fact that the holding step 3a of the plug part 3 has already passed over the entire first, converging inclined surface 7a and has also passed a radially inward-facing holding edge 7b. Once this has happened, the plug-in movement can be terminated and the plug part 3 can be released.

[0050] Due to the holding part 6 being carried along by the plug part 3 in the plugging direction S, the outer holding and guiding segment 21 has moved onto the outer inclined surface 4d of the socket part 4 during plugging and has thereby experienced a radial deflection - as during the pre-assembly of the holding part 6 and socket part 4. The locking hooks 10a of the snap arms 10 have also moved axially away from the locking step 12 on the outer circumference 11 of the socket part 4 in the plugging direction S as a result of the plugging. After the plug part is released, the above-described interaction of the outer holding and guiding segment 21 with the inclined surface 4d of the socket part 4, which diverges in the plugging direction S, takes effect. The spring elasticity of the outer holding and guiding segment 21, in conjunction with the inclined surface 4d, causes an automatic axial backward displacement of the holding part 6 against the plugging direction S, so that the Fig. 3 is assumed, in which the receiving part 2 is again in the locking position. In this case, the holding step 3a of the plug part 3, i.e. its ring shoulder, now rests on a second inclined surface 7c which diverges in the plug-in direction S and is located behind the holding edge 7b of the holding arm 7 when viewed in the plug-in direction S. The force of the holding step 3a, which is directed axially opposite to the plug-in direction S and is caused by the outer holding and guide segments 21 in cooperation with the inclined surface 4d and which is possibly further amplified in the operating state by the force of the operating pressure of a fluid guided in the plug-in coupling 1 according to the invention, in turn tends to spread the holding arms 7 apart, which, however, is prevented by their external contact with the lugs 23a of the holding claws 23.

[0051] To disassemble the plug-in coupling 1 according to the invention, it should first be relieved of the operating pressure of the fluid. Then, the socket part 4 and the holding part 6 must be pressed together in the axial direction XX against the interaction of the outer holding and guide segments 21 of the holding part 6 with the outer inclined surface 4d of the socket part 4, until the Fig. 11 shown axial position of the holding arms 7 is reached, in which they are released by the holding claws 23.

[0052] The plug part 3 can also be used to advantage for pressing together. To enable this, the holding part 6 can have a third inclined surface 7d on the holding arms 7 of the holding part 6, which again converges in the plugging direction S. In addition, for this purpose, a stop surface 22c with the same function can be provided on the inner holding and guide segments 22 located between the holding arms 7, namely with the function that when the plug part 3 is plugged over - from the assembly position ( Fig. 4) further in the plug-in direction S - the holding step 3a of the plug part 3 comes into contact. Further pressing of the plug part 3 in the plug-in direction S causes a relative movement of the holding part 6 and the socket part 4 against each other until the desired release position of the holding arms 7 is reached. This type of disassembly also represents a simplification compared to the known prior art and therefore offers increased ease of use of the fluid plug-in coupling 1 according to the invention.

[0053] The invention is not limited to the illustrated embodiments, but also encompasses all equivalent embodiments within the meaning of the invention. Thus, the receiving part 2 according to the invention does not necessarily have to have three holding arms 7 offset by 120° from one another and three snap arms 10 offset by 120° from one another on the holding part 6 according to the invention. Rather, two could be sufficient, or four or more holding arms 7 and snap arms 10 could be provided. The segmentation of the outer and inner holding and guide segments 21, 22 would then have to be designed accordingly.

[0054] Furthermore, the invention can also be supplemented by further expedient and original technical embodiments without departing from the scope of the invention. For example, a joint 27 can be provided on the base 25 of the socket part 4, as shown in Fig. 11. At such a joint 27, a particularly material-to-material connection, such as by laser welding or gluing, can be made with a further line connection element 28, such as a mandrel. This advantageously enables the integration of a fluid plug-in coupling 1 according to the invention into a fluidic modular system. On the other hand, it is also possible to design such a further line connection element 28 in one piece with the socket part 4, as is shown in Fig. 1 to 4 and from Fig. 8 and Fig. 10 and as is also provided for in the second embodiment of the invention.

[0055] The inclined surface 4d diverging in the plug-in direction S on the casing 4c of the socket part 4 can be provided with a color marking for easy indication of the plug-in state of the fluid plug-in coupling 1 according to the invention. This immediately shows the extent to which this inclined surface 4d is currently covered by the outer holding and guiding segment 21. Alternatively or additionally, other parts can also be specially colored for marking purposes. For example, the holding claws 23 of the socket part 4 can protrude from the holding part 6 in the release position, which can be indicated by a colored marking of the casing 4c. The inclined surface 4b and / or the end face 4a of the socket part 4 intended for interaction with the snap arm 10 can also be color-coded.

[0056] The ergonomic improvement of the haptics mentioned at the outset, which is possible by avoiding openings in the receiving part 2 according to the invention, can be realized, for example, by providing a circumferential knurling 29 or a knurling 30 running in the axial longitudinal direction XX on the outer circumference - i.e. in the outer casing area 9 - of the receiving part 2, preferably of the holding part 6, as shown in Fig. 7 is indicated as an example.

[0057] In order to minimize the size of a receiving part 2 according to the invention, in particular to minimize the diameter in the outer casing area 9 of the holding part 6, the inner contour 31 of the receiving opening 5 in the socket part 4 can advantageously be shaped to match the respective bending line of the holding arms 7 of the holding part 6. The inner contour 31 thus adapted to the holding arms 7 is shown in the drawings of the socket part in Fig. 3, Fig. 8 and Fig. 9 registered.

[0058] The enlarged and perforation-free free area on the outer circumference 11 of the sleeve part 4, compared to the state of the art mentioned at the beginning, offers an excellent opportunity, if heating is required, to place heating elements 32 thereon and / or to wind heating strands 33 around it. This is shown in Fig. 2 indicated.

[0059] Due to the fact that the retaining claws 23 are already separated in the pre-assembled state of the socket part 4 and the holding part 6 in the inner casing area 13 of the holding part 6 by the inner holding and guide segments 22 arranged circumferentially between two adjacent retaining claws 23, an anti-twist protection of the socket part 4 and the holding part 6 is advantageously provided. In this case, it can also be provided in particular that frontal windows 34 (see Fig. 1, Fig. 2, Fig. 5, Fig. 7, Fig. 8) are inserted, into which the holding claws 23 protrude together with the holding arms 7 of the holding part 6.

[0060] The drawing - starting from Fig. 12 - relates to a second preferred embodiment of a fluid plug-in coupling 1 according to the invention with a receiving part 2 according to the invention. As a comparison between the first embodiment in Fig. 1 and the second version in Fig. 12 shows, the two designs differ in that in the second design, the receiving part 2 according to the invention is associated with a further component. This component fulfills the function of a secondary locking mechanism, i.e., it ensures that the fully assembled fluid plug-in coupling 1 according to the invention cannot spontaneously open again under the influence of the environment, e.g., due to collision with other components, vibration, etc. The component is therefore referred to as the secondary locking part 50, although for the sake of simplicity, the abbreviation "locking part 50" will be used below. The locking part 50 is designed as a coupling part for the holding part 6 and, together with the latter, also fulfills the function of a plug-in indicator, i.e., it indicates whether the plug part 3 is plugged into the receiving part 2 in the correct position or not. Roman numerals I, II, III, IV are used in Fig. 12 shows the assembly sequence of the parts of the receiving part 2 according to the invention: I - the socket part 4 is prepared, II - the sealing arrangement 14 is inserted into the socket part 4, III - the locking part 50 is placed on the socket part 4, IV - the holding part 6 is inserted into the locking part 50 and connected to the socket part 4. The receiving part 2 according to the invention then looks as shown in Fig. 21 to 25.

[0061] As the comparison between the first version in Fig. 1 and the second version in Fig. As further shown in Figure 12, the sleeve part 4 and the holding part 6 of the two embodiments of the receiving part 2 according to the invention do not differ in their basic structure. However, in the second embodiment, there are some special features that differ from the first embodiment of the receiving part 2 according to the invention - apart from the presence of the locking part 50 - which, however, Fig. 12 and are explained in more detail below together with the functioning of the secondary locking mechanism with reference to the other figures.

[0062] In Fig. 13 to 16, the holding part 6 of the second embodiment of the invention is shown as an individual part. As can be seen therefrom, the holding part 6 of the second embodiment differs from that of the first embodiment in that an indicator segment 61 is formed in the inner casing region 13 between two holding arm segments 7 - opposite a snap-arm segment 10 in the outer casing region 9. An inner holding and guiding segment 22 is thus converted into the indicator segment 61. The indicator segment 61 indicates whether a plug part 3 is inserted into the receptacle part 2 according to the invention or not.

[0063] The shape of the indicator segment 61 is best described in the sectional views in Fig. 14 and Fig. 15. As can be seen therefrom, the indicator segment 61 is rooted in the foot region 17 of the inner jacket region 13 and projects axially from there opposite to the plug-in direction S. It has the shape of a U, with the connecting web 61a of the U, which connects a radially inner leg 61b and a radially outer leg 61c of the U, lying in the head region 8 of the holding part 6. The inner leg 61b is integrated at its end into the foot region 17 of the inner jacket region 13, while the outer leg 61c has a free end which is radially outer opposite the foot region 13 of the inner jacket region 13 and is equipped with a radially outward-pointing nose 61d. According to this design, the indicator segment 61 acts as a spring-elastic double bending lever which interacts with the plug part 3.

[0064] As further stated Fig. As can be seen from Figures 13 to 16, the holding part 6 of the second embodiment differs from that of the first embodiment in that, in its head region 8, further, in particular smaller, windows 34a are located circumferentially between the windows for the claws 23 of the sleeve part 4 and the holding arms 7 of the holding part 6. These windows have an advantageous material-saving effect and ensure that the holding part 6 can be easily removed from an injection mold during its manufacture. Furthermore, a window 35 is provided in the head region 8, through which the indicator segment 61 is accessible from the front.

[0065] In Fig. 17 and Fig. 18, the sleeve part 4 of the second (and third) embodiment of the invention is shown as an individual part. As can be seen from the drawing, the sleeve part 4 of the second (and third) embodiment differs from that of the first embodiment in that in the sleeve part 4, axially in the plug-in direction S, immediately behind its locking step 12 located on the outer circumference 11, but with a circumferential angular offset, an indicator window 36 is provided, which is intended for the penetration of the nose 61d of the indicator segment 61 when the holding part 6 is placed on the sleeve part 4, as is the case, for example, Fig. 23, Fig. 25 and Fig. 26. If the plug part 3 is not or not yet fully inserted ( Fig. 23 and Fig. 25), the nose 61d of the indicator segment 61 protrudes through the indicator window 36 and projects beyond the outer circumference 11 of the sleeve part 4.

[0066] However, if the plug part 3 is fully inserted ( Fig. 26), the connecting area 61a of the U and the lower part of the two U-legs 61b, 61c of the indicator segment 61 are pushed radially outwards by the holding step 3a of the plug part 3 under spring-elastic deformation. The area lying between the claws 23 in the area of ​​the head-side recess 24 (in Fig. 23, Fig. 25 and Fig. 26 (designated with the reference numeral 23a) of the sleeve part 4 acts like a bearing of a rocker on the indicator segment 61, which acts as a double bending lever. Although the latter undergoes the described spring-elastic deformation, it is still sufficiently rigid that the free end of its radially outer leg 61c is pushed radially inward under the leverage effect. As a result, the nose 61d of the indicator segment 61 in the indicator window 36 reaches a position in which it no longer protrudes from the outer circumference 11 of the sleeve part 4, but is flush with it. A slight tolerance radially inward and outward is possible, but this tolerance is so small that it does not impair the function of the nose 61d in interaction with the secondary locking element 50, which is described below.

[0067] As further stated Fig. 17 to 18, the sleeve part 4 of the second (and third) embodiment differs from that of the first embodiment further in that, in an axial region—lying behind the locking step 12 and the indicator window 36 in the plug-in direction S—at least one radially outwardly projecting web projection 37 is located on its outer circumference 11, preferably three radially outwardly projecting web projections 37, circumferentially offset from one another by 120°. These web projections 37, which could also be referred to as flange sections, are also intended for interaction with the secondary locking part 50.

[0068] Finally, the socket part 4 of the second (and third) embodiment differs from that of the first embodiment in that it also has an axial region in the plug-in direction S behind the locking step 12 - in Fig. 17 diametrically opposite the indicator window 36 - on its outer circumference 11 there is at least one radially projecting locking projection 38 for the secondary locking part 50.

[0069] In Fig. 19 and Fig. 20, the secondary locking part 50, which is to be regarded as a specific feature of the second (and also the third) embodiment of the invention, is shown as an individual part. The secondary locking part 50 serves to prevent an unintentional release of a fluid plug-in coupling 1 according to the invention. It is a coupling part for the combination of sleeve part 4 and holding part 6, thus encompassing these two parts 4, 6 on the outside in the assembled state, in particular directly the outer casing area 9 of the holding part 6, as is the case with the further Fig. 21 to 35.

[0070] The secondary locking part 50 is annular and, like the sleeve part 4 and the holding part 6, can be easily manufactured as a one-piece plastic injection-molded part. In the illustrated embodiment, it has six axially directed, radially resiliently expandable snap arms 51, 52. Furthermore, the locking part 50 has at least one radially inward-facing lug 53, three lugs 53 in the illustrated embodiment, for interacting with the holding part 6.

[0071] The snap arms 51, 52 are separated from each other by slots 54, which extend from a base region 55 of the locking part 50, circumferentially interrupted by the slots 54, and end in a circumferentially closed head region 56. The number of snap arms 51, 52 can be varied. In the minimum design of the locking part 50, two snap arms 51, 52 are provided.

[0072] There are three shorter snap arms 51 and three longer snap arms 52 in circumferentially alternating order. The longer snap arms 52 can be easily identified in the drawing figures by the fact that they have a grooved grip area 57 designed in an ergonomically favorable manner in order to be able to rotate the locking part 50 more easily about its longitudinal axis XX.

[0073] All snap arms 51, 52 have radially inwardly directed lugs 51a, 52a in the base area 55 for engaging behind the holding part 6.

[0074] The shorter snap arms 51 can be easily identified in the drawing figures by the fact that they have a radially inner recess 58 for interacting with the locking projection 38 of the sleeve part 4 and with the nose 61d of the indicator segment 61 of the holding part 6.

[0075] Furthermore, particularly in the area of ​​the longer snap arms 52, radially inwardly projecting stops 59 are arranged on the secondary locking part 50 for corresponding stops formed by the side surfaces of the snap arms 10 of the holding part 6, which circumferentially limit a rotational movement of the locking part 50 about its longitudinal axis XX. These stops 59 are located at an axial distance from the head region 56 of the locking part 50 that is even smaller than the length of the shorter snap arms 51.

[0076] After the already mentioned assembly of the receiving part 2 according to the invention in the sequence I, II, III, IV according to Fig. 12 the receiving part 2 according to the invention looks in plan view as it is in Fig. 21. The side view is shown in Fig. 22 and a corresponding longitudinal section in Fig. 23. In this regard, it has already been emphasized as a specific feature of the second embodiment of the invention that the nose 61d of the indicator segment 61 of the holding part 6 engages through the indicator window 36 of the sleeve part 4 and protrudes beyond the outer circumference of the sleeve part 4 at this point. However, it was not mentioned above that the nose 61d engages in the recess 58 in the nose 51a of a shorter snap arm 51, as is shown by Fig. 24 (top). The locking part 50 cannot be rotated about the longitudinal axis XX. The same applies at the beginning of the insertion of the plug part 3, if a condition exists as shown in Fig. 25 is present.

[0077] If the plug part 3 is fully inserted ( Fig. 26), then - as already explained above - the nose 61d of the indicator segment 61 is moved in the direction of the arrow F in Fig. 27 and Fig. 28 is moved radially inward so that it no longer engages in the recess 58 in the nose 51a of the snap arm 51. The radially inner leg 61b and the radially outer leg 61c of the indicator segment 61 are thereby resiliently pressed against each other. The secondary locking part 50 is thus released for rotation. The rotation takes place until the Fig. 29 to Fig. 32 is reached. This state is characterized by the fact that the locking projection 38 of the sleeve part 4 now engages in the recess 58 in the nose 51a of a shorter snap arm 51. The angle of rotation is limited - as already indicated - by the radially inwardly projecting stops 59 located on the secondary locking part 50, in that these each come to a stop laterally on the snap arms 10 of the holding part 10, as shown in Fig. 30 and Fig. 31. This state represents the locking position for the following reason.

[0078] As already described in the first embodiment of the invention, in order to disassemble the plug-in coupling 1 according to the invention, after relieving the operating pressure of the fluid, the socket part 4 and the holding part 6 must be pressed together in the axial direction XX against the interaction of the outer holding and guide segments 21 of the holding part 6 with the outer inclined surface 4d of the socket part 4, until, as in Fig. 11, an axial position of the holding arms 7 is reached, in which they are released by the holding claws 23. In this case, an assembly path is decisive or necessary, which is Fig. 22 and Fig. 29 is designated by the reference symbol W. This mounting path W can be used by the holding part 6 in the locking position ( Fig. 29) cannot be moved back, since it is firmly connected to the secondary locking part 50 and the secondary locking part 50 cannot move in the axial direction because in the locking position its longer snap arms 52 abut in the axial direction against the web shoulder 37 of the sleeve part 4, as is the case, for example, with the upper part of Fig. 29 can be seen.

[0079] In order for the disassembly to take place, the condition must first be restored to Fig. 22, i.e. the locking projection 38 of the sleeve part 4 and the recess 58 in the nose 51a of the shorter snap arm 51 must be disengaged. This requires a positive-locking locking connection between the nose 51a of the snap arm 51 and the locking projection 38. This can be achieved - as illustrated by the drawing - by the locking projection 38 having a rounded contour and the recess 58 in the nose 51a of the shorter snap arm 51 having inner lateral bevels. These are only shown in Fig. 30 with the reference numeral 58a. Likewise, in order for the locking connection to be established beforehand, ie so that the nose 51a can be overrun by the locking projection, outer lateral inclined surfaces 58b are also provided, which also only Fig. 30 are designated.

[0080] By turning the secondary locking part back to the Fig. 22 shown position is achieved so that the shorter snap arms 51 are now located in the area of ​​the web attachment 37 ( Fig. 22, above), so that the disassembly path W can be covered. The longer snap arms 52 are located in positions between the web projections 37, as already shown by Fig. 12, which also enables the axial displacement of the holding part 6 connected to the locking part 50 along the sleeve part 4 required for disassembly.

[0081] To carry out the disassembly movement, the secondary locking part 50 can be pressed in the plugging direction S, whereby the pressure is applied via the lugs 53 (in Fig. 33 additionally circled) is transferred evenly from the secondary locking part 50 to the holding part 6. The Fig. 33 - as well as the other Fig. 29 and Fig. 32 - plug part 3, not shown for the sake of clarity, can then be removed from the receiving part 2, so that the connection of the fluid plug-in coupling 1 according to the invention is removed again.

[0082] At the Fig. 35, which is characterized in that it has three indicator segments 61 on the holding part 6, the assembly and disassembly takes place analogously to the second embodiment.

[0083] The invention is not limited to the feature combinations defined in independent claims 1 and 34, but can also be defined by any other combination of specific features of all individual features disclosed overall. This means that, in principle, practically every individual feature of the independent claims can be omitted or replaced by at least one individual feature disclosed elsewhere in the application. Reference symbol 1 fluid plug-in coupling 2 mounting parts for 1 3 plug part for 1 3a holding level of 3 3b top of 3 4 socket part of 2 4a Front side of 4 4b Inclined surface at 4a for interaction with 10b 4c coat of 4 4d in plug-in direction S diverging inclined surface on 4c 5 mounting opening in 4 for 3 6 holding part of 2 7 holding arm from 6 for 3 in 13 7a first inclined surface of 7 converging in direction S 7b Holding edge of 7 for 3 between 7a and 7c 7c second inclined surface of 7 diverging in direction S 7d third inclined surface of 7 converging in direction S 8 head area of ​​6 9 Outer sheath area of ​​6 with 10 10 snap arm from 6 for 4 in 9 10a locking hooks from 10 for 12 10b Inclined surface of 10 for interaction with 4b 10c diverging bevel at 10a for 12a 11 outer circumference of 4 12 locking step to 11 12a diverging bevel at 12 for 10c 13 inner jacket area of ​​6 with 7 14 Seal arrangement in 5 15 sealing ring of 14 16 spacer ring of 14 17 foot area of ​​13 (6) 18 holding paragraph for 14 in 5 of 4 19 slot in 9 20 slot in 13 21 outer holding and guiding segment in 9 22 inner holding and guiding segment in 13 22c Stop surface of 22 23 retaining claw of 4 23a Nose of 23 24 frontal recess of 4 next to 23 25 floor of 4 26 inside heel in 4, stop for 6 27 joint 28 Cable connection element 29 circumferential knurling 30 axial knurling 31 to 7 coordinated inner contour in 5 32 heating elements 33 heating strands 34 windows in 8 for 23 34a window in 8 35 windows in 8 for 61 36 indicator windows in 4 for 61d 37 Bridge attachment at 4 for interaction with 50 38 locking attachment on 4 for 50 50 Secondary locking part of 2 (second / third version, Fig. 12 to 35) 51 shorter snap arm of 50 51a Nose on 51 52 longer snap arm of 50 52a Nose on 52 53 Nose from 50 to 56 54 slots in 50 between 51 and 52 55 floor area of ​​50 56 head area of ​​50 57 Grip area on 52 58 Recess in 51a for interaction with 38 and 61d 58a inner lateral inclined surfaces of 58 ( Fig. 30) 58b outer lateral bevels of 58 ( Fig. 30) 59 attack of 50 for 4 61 indicator segment of 6 (second and third execution, Fig. 12 to 35) 61a U-connection area of ​​61 61b radial inner leg of 61 61c radial outer leg of 61 61d Nose on 61c to interact with 58 A Axial play 3b / 25, 14 / 18, 22 / 26, 4a / 8 F Direction of movement of 61d ( Fig. 27 and Fig. 28) S Plug direction from 3 to 2 and from 6 to 4 W Disassembly path of 50 (second and third version, Fig. 22 and Fig. 29) XX Longitudinal axis of 1, 2, 3, 4

Claims

[1] Receiving part (2) for a fluid plug-in coupling (1), with a socket part (4) which has a receiving opening (5) for a plug part (3) which can be inserted into the socket part (4) in an axial insertion direction (S), and with an expandable holding part (6), by means of which the plug part (3) can be locked in a latching manner via a holding step (3a) of the plug part (3) against being released from the socket part (4), wherein the holding part (6) has at least one radially resiliently expandable holding arm (7) for latchingly engaging behind the holding step (3a) of the plug part (3), wherein the holding part (6) engages over the socket part (4) with an annular head region (8) on the end face, wherein the holding part (6) has at least one in an outer casing region (9) which extends axially from the head region (8) in the direction of the socket part (4). protruding,radially resiliently expandable snap arm (10) for engaging behind a locking step (12) located on the outer circumference (11) of the socket part (4), which is concentric with the radially resiliently expandable holding arm (7) for engaging behind the holding step (3a) of the plug part (3), which is arranged in an inner casing region (13) of the holding part (6), wherein in the outer casing region (9) viewed in the circumferential direction, in particular radially resiliently expandable outer holding and guide segments (21) are located between the snap arms (10). [2] Receiving part (2) according to claim 1, characterized by that three holding arms (7) offset by 120° from one another and three snap arms (10) offset by 120° from one another are formed on the holding part (6), which each form segments in the inner jacket area (13) and in the outer jacket area (9). [3] Receiving part (2) according to claim 1 or 2, characterized bythat the holding arms (7) and the snap arms (10) are arranged alternately in the circumferential direction with a mutual angular offset, in particular with a mutual angular offset of 60°. [4] Receiving part (2) according to one of claims 1 to 3, characterized by that the sleeve part (4) and / or the holding part (6) are each manufactured as one-piece parts, in particular as injection-molded parts made of plastic. [5] Receiving part (2) according to one of claims 1 to 4, characterized by that the snap arms (10) each have a locking hook (10a) with a radially inwardly directed tip for engaging behind the locking step (12) located on the outer circumference (11) of the sleeve part (4). [6] Receiving part (2) according to one of claims 1 to 4, characterized bythat the snap arms (10) each have a latching hook (10a), at the tip of which an inclined surface (10b) diverging in the plug-in direction (S) is formed for interaction with the sleeve part (4), in particular with a complementary inclined surface (4b) located radially outward on the end face (4a) of the sleeve part, also diverging in the plug-in direction (S). [7] Receiving part (2) according to one of claims 1 to 6, characterized by that a sealing arrangement (14) for circumferentially sealing the inserted plug part (3) is arranged in the receiving opening (5) of the sleeve part (4), which sealing arrangement comprises one or more annular seals (15) and preferably consists of two sealing rings (15) with a spacer ring (16) arranged between the sealing rings (15), wherein the sealing arrangement (14) is fixed in particular by the holding part (6) in the axial direction against movement opposite to the plug-in direction (S). [8] Receiving part (2) according to claim 7, characterized by that a circumferentially surrounding inner holding shoulder (18) is formed in the receiving opening (5) of the sleeve part (4), by means of which the sealing arrangement (14) is fixed in the axial direction (XX) against movement in the plug-in direction (S). [9] Receiving part (2) according to one of claims 1 to 8, characterized by that a foot region (17) of the inner casing region (13) of the holding part (6), which foot region is axially diametrically opposite the head region (8) of the holding part (6), is designed as a closed ring, from which the resiliently expandable holding arms (7) project axially opposite the plug-in direction (S) for engaging behind the holding step (3a) of the plug part (3). [10] Receiving part (2) according to one of claims 1 to 9, characterized bythat the radially spring-elastically expandable snap arms (10) for the sleeve part (4) are formed by slots (19) in the outer casing area (9) of the holding part (6), which are open on their side facing the sleeve part (4) and end in the head area (8). [11] Receiving part (2) according to one of claims 1 to 10, characterized by that the radially spring-elastically expandable holding arms (7) for the plug part (3) are formed by slots (20) in the inner casing region (13) of the holding part (6), which are open on their side facing away from the socket part (4) and end in a / the foot region (17) of the inner casing region (13). [12] Receiving part (2) according to one of claims 1 to 11, characterized by that in the inner casing area (13) seen in the circumferential direction, inner holding and guide segments (22) are located between the holding arms (7). [13] Receiving part (2) according to claim 12, characterized bythat in each case an inner holding and guiding segment (22) is located opposite one snap arm (10) in the outer casing region (9) - viewed in the radial direction - in the inner casing region (13) and that in each case an outer holding and guiding segment (21) is located opposite one holding arm (7) in the inner casing region (13) - viewed in the radial direction - in the outer casing region (9). [14] Receiving part (2) according to one of claims 1 to 13, characterized bythat on a jacket (4c) of the sleeve part (4) there is an inclined surface (4d) which diverges in the plug-in direction (S), which causes a spring-elastic radial deflection of the outer holding and guiding segment (21) when the holding part (6) is plugged onto the sleeve part (4) and, after plugging, a radial resetting of the outer holding and guiding segment (21) with axial backward displacement of the holding part (6) against the plug-in direction (S), wherein preferably the diverging inclined surface (4d) and / or the jacket (4c) and / or an inclined surface (4b) intended for interaction with an inclined surface (10c) of the snap arm (10) and / or an end face (4a) of the sleeve part (4) is / are marked in color. [15] Receiving part (2) according to one of claims 1 to 14, characterized bythat the sleeve part (4) has, on its side facing the holding part (6), holding claws (23), preferably three holding claws (23) offset from one another by 120°, for locking and releasing the radially spring-elastic spreading of the holding arms (7). [16] Receiving part (2) according to claim 15, characterized by that the holding claws (23) for locking and releasing the radially spring-elastic spreading movement of the holding arms (7) have noses (23a) with a radially inwardly directed tip, which in the locking position come into contact with the radially outwardly directed side of the holding arms (7), wherein the holding arms (7) preferably exert a radially acting force on the noses (23a) in the locking position. [17] Receiving part (2) according to one of the preceding claims, characterized bythat in the receiving opening (5) of the sleeve part (4) between a / the sealing arrangement (14) and a / the holding shoulder (18) for this sealing arrangement (14), between an / the inner holding and guide segment (22) and a circumferential inner shoulder (26) of the sleeve part (4), which forms an axial stop for the holding part (6) when the holding part (6) is axially inserted into the sleeve part (4), and between an end face (4a) of the sleeve part (4) in the region of an end-face recess (24) and an underside of the head region (8) facing the sleeve part (4) in the region of the snap arms (10) there is an axial play (A). [18] Receiving part (2) according to one of the preceding claims, characterized bythat the holding part (6) has on its holding arms (7) an inclined surface (7d) converging in the plug-in direction (S) and / or a stop surface (22c) is formed on inner holding and guide segments (22) located between the holding arms (7), wherein when the plug part (3) is plugged over from its assembly position further in the plug-in direction (S) the holding step (3a) of the plug part (3) comes to rest on the inclined surface (7d) and / or on the stop surface (22c). [19] Receiving part (2) according to one of the preceding claims, characterized by that a joint (27) for a material-locking connection, in particular by laser welding or gluing, with a line connection element (28), such as a mandrel, is formed on a base (25) of the sleeve part (4), or that a line connection element (28) is designed in one piece with the sleeve part (4). [20] Receiving part (2) according to one of the preceding claims, characterized bythat in the outer casing area (9) of the receiving part (2) a circumferential knurling (29) or grooves (30) running in the axial direction (XX) are provided. [21] Receiving part (2) according to one of the preceding claims, characterized by that an inner contour (31) of the receiving opening (5) in the sleeve part (4) is formed onto a bending line of the holding arms (7) of the holding part (6). [22] Receiving part (2) according to one of the preceding claims, characterized by that heating elements (32) and / or heating strands (33) are arranged on the outer circumference (11) of the sleeve part (4). [23] Receiving part (2) according to one of the preceding claims, characterized by that an inclined surface (10c, 12a) diverging in the plug-in direction (S) is provided on the locking step (12) and on the snap-in arm (10), wherein the inclined surfaces (10c, 12a) are in particular designed to be complementary to one another in such a way that they wedge into one another in the operating state. [24] Receiving part (2) according to one of the preceding claims, characterized by that a particularly annular secondary locking part (50) is assigned to the holding part (6) as a coupling part. [25] Receiving part (2) according to claim 24, characterized by that the secondary locking part (50) has at least two, preferably six, axially directed, radially resiliently expandable snap arms (51, 52), which are preferably separated from one another by slots (54) and have radially inwardly directed lugs (51a, 52a) in a base region (55) of the secondary locking part (50), wherein preferably shorter snap arms (51) and longer snap arms (52) alternate circumferentially. [26] Receiving part (2) according to claim 24 or 25, characterized bythat the secondary locking part (50) has at least one radially inwardly facing nose (53), preferably three radially inwardly facing noses (53), in a head region (56) for cooperation with the holding part (6). [27] Receiving part (2) according to one of claims 24 to 26, characterized by that radially inwardly projecting stops (59) for the sleeve part (4) are arranged on the secondary locking part (50), in particular in the region of the longer snap arms (52), which circumferentially limit a rotational movement of the locking part (50) about its longitudinal axis (XX). [28] Receiving part (2) according to one of the preceding claims, characterized bythat in the inner casing region (13) of the holding part (6) between two holding arm segments (7) opposite a snap arm segment (10) in the outer casing region (9) there is formed an indicator segment (61), which acts in particular as a spring-elastic double bending arm interacting with the plug part (3). [29] Receiving part (2) according to claim 28, characterized by that the indicator segment (61) has the shape of a U, wherein a connecting web (61a) of the U connects a radially inner leg (61b) and a radially outer leg (61c) of the U, wherein the inner leg (61b) is integrated at the end into a / the foot region (17) of the inner casing region (13) and projects axially from the foot region (17) counter to the plug-in direction (S), while the outer leg (61c) has a free end which is radially outside opposite the foot region (17) of the inner casing region (13) and has a radially outward-pointing nose (61d). [30] Receiving part (2) according to claim 29, characterized by that the sleeve part (4) has an indicator window (36) for receiving the nose (61d) of the indicator segment (61). [31] Receiving part (2) according to one of the preceding claims, characterized by that the sleeve part (4) has in an axial region - in the plug-in direction (S) behind the locking step (12) and optionally behind the indicator window (36) - on its outer circumference (11) at least one radially outwardly projecting web projection (37), preferably three radially outwardly projecting web projections (37) offset from one another circumferentially by 120° for interaction with a / the secondary locking part (50). [32] Receiving part (2) according to one of the preceding claims, characterized bythat the sleeve part (4) has in an axial region - in the plug-in direction (S) behind the locking step (12) on its outer circumference (11) at least one radially outwardly projecting locking projection (38) for the / a secondary locking part (50). [33] Fluid plug-in coupling (1) with a receiving part (2) and with a plug part (3) which can be inserted in an axial (XX) insertion direction (S) into a receiving opening (5) of a socket part (4) of the receiving part (2), characterized by that the receiving part (2) is designed according to one of claims 1 to 32. [34] Fluid plug-in coupling (1) according to claim 33, characterized by that the shape of a base (25) in the receiving opening (5) of the socket part (4) is adapted to the shape of a tip (3b) of the plug part (3). [35] Fluid plug-in coupling (1) according to claim 33 or 34, characterized bythat in the receiving opening (5) of the socket part (4) there is an axial play (A) between a / the tip (3b) of the plug part (3) and a / the bottom (25) of the socket part (4) in the assembled state. [36] Fluid plug-in coupling (1) according to one of claims 33 to 35, characterized by that in the socket part (4) there is an indicator window (36) which is intended for the penetration of a nose (61d) of an indicator segment (61) of the holding part (6), wherein the nose (61d) projects through the indicator window (36) and projects relative to the outer circumference (11) of the socket part (4) when the plug part (3) is not or not fully plugged in, and wherein the nose (61d) does not project through the indicator window (36) relative to the outer circumference (11) of the socket part (4) when the plug part (3) is fully plugged in.

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