FIELD OF THE INVENTION

The invention relates to a plug-in hose coupling for the non- detachable connection of hoses or tubes composed of plastic or elastomeric material,

- having a housing input part which has a receiving bore and in which the receiving bore is widened in an end region which faces towards the interior of the coupling, - having a tubular support sleeve which projects concentrically into the interior of the housing input part proceeding from the widened end region, onto which tubular support sleeve a tube or hose end can be pushed as far as an end-side stop which is situated at the end of the support sleeve, with the support sleeve being sealingly clipped into the widened end of the receiving bore by means of an annular collar which is situated at one end of said support sleeve and has multiple outward U-shaped deflections, with at least one annular seal which bears against the inner periphery and one annular holding element which bears axially against the seal for a tube end which can be plugged into the free end of the receiving bore being arranged concentrically in the space, which is formed by the collar of the support sleeve and the housing input part, in the region of the widening of the receiving bore, with the holding element being embodied in the form of an open lock washer and being supported against an inner conical support face of the housing input part in the region of the widening of the receiving bore, which support face narrows conically counter to the plug-in direction of the tube end, and with the holding element having encircling cutting edges on the inner periphery,

- having a fastening part, which has a throughflow bore which is aligned with the receiving bore, for attaching the plug-in hose coupling to a motor vehicle unit. BACKGROUND OF THE INVENTION

Plug-in hose couplings are attachment fittings which are also referred to as quick-action plug-in connections.

Said plug-in hose couplings are used primarily in low-pressure systems in which plastic tubes or hoses are often provided for conveying fluid.

Below, for simplification, the term "tube" is also used for hoses.

The plug-in hose couplings have the advantage that the tube can be fixedly connected to the plug-in hose coupling by means of simple insertion into the receiving bore.

This leads to a considerable simplification of assembly, which is important primarily in vehicle construction.

The fixing of the tube in the plug-in hose coupling is brought about by an integrated holding element which is radially resilient. In said plug-in hose couplings, the resilient holding element is often embodied either as a plate-spring-like, closed or open toothed disc ring or as a slotted lock washer with one or more cutters.

As the tube is passed through, the annular holding element is firstly slightly opened, so that it lies with a slight radial contact pressure around the outer surface of the tube.

This takes place relatively easily since the annular holding element is usually conically beveled or widened in the plug-in direction. The widening can also take place by means of a pilot ring which is arranged in front of the tube end and is provided with an insertion cone. When the tube is pulled back, the cutters or teeth then dig into the outer surface of the tube and prevent the tube from being pulled back further.

In the case of a slotted, correspondingly conically formed lock washer, a conical support face is necessary for this purpose, against which the lock washer is supported with its outer face and whose conicity is arranged such that the diameter of the lock washer is reduced in the pulling-out direction of the tube. In this way, the holding force of the lock washer is increased with increasing pulling-out force. Attachment fittings of said type are known for example from DE 39 23 579 A1 , DE 9208519 U1 or DE 43 00 004 A1 , with DE 39 23 579 A1 disclosing a system with a toothed disc or lock washer, and with DE 9208519 U1 and DE 43 00 004 A1 disclosing a system with a lock washer. In the plug-in hose couplings described, said components, such as seals, conical support rings and holding rings or lock washers are arranged in a predetermined sequence in the throughflow bore of the housing and are fixedly held in position by rolling in or flanging the wall of the housing in the throughflow bore. A disadvantage of all of said solutions is that, for holding all of the components required for sealing and for fixing the tube in the plug-in hose coupling in the housing, a relatively long bore, and when using a slotted lock washer, an additional wedge element, are required.

As a result, firstly the production and handling of the housing blanks is complex, and secondly the assembly with an additional component, the wedge element, is also encumbered.

BRIEF DESCRIPTION OF THE INVENTION

The invention is based on the object of creating a plug-in hose coupling of the type described in the introduction which is characterized by simple assembly with few components.

Said object is achieved by means of the features of a plug-in hose coupling for the non-detachable connection of hoses or tubes composed of plastic or elastomeric material, - having a housing input part which has a receiving bore and in which the receiving bore is widened in an end region which faces towards the interior of the coupling,

- having a tubular support sleeve which projects concentrically into the interior of the housing input part proceeding from the widened end region, onto which tubular support sleeve a tube or hose end can be pushed as far as an end-side stop which is situated at the end of the support sleeve, with the support sleeve being sealingly clipped into the widened end of the receiving bore by means of an annular collar which is situated at one end of said support sleeve and has multiple outward U-shaped deflections, with at least one annular seal which bears against the inner periphery and one annular holding element which bears axially against the seal for a tube end which can be plugged into the free end of the receiving bore being arranged concentrically in the space, which is formed by the collar of the support sleeve and the housing input part, in the region of the widening of the receiving bore, with the holding element being embodied in the form of an open lock washer and being supported against an inner conical support face of the housing input part in the region of the widening of the receiving bore, which support face narrows conically counter to the plug-in direction of the tube end, and with the holding element having encircling cutting edges on the inner periphery,

- having a fastening part, which has a throughflow bore which is aligned with the receiving bore, for attaching the plug-in hose coupling to a motor vehicle unit, with the fastening part being non-detachably joined together with the unit of axially plugged into one another housing input part and support sleeve by overmoulding of an outer connecting section (overmoulding portion) or being formed by means of overmoulding of the unit itself.

By "overmoulding" is meant in the present text any process allowing the formation of a part having a determined shape and wherein at least a portion of said part coats one or more other parts. Preferably, overmoulding is carried out by injection of a plastic material into a mould, the invention not being limited to this technique.

The arrangement according to the invention has the advantage that the inner annular seal and the holding element, which seal off and fixedly hold the tube which can be pushed in during the later final assembly, are arranged in the housing input part. It is possible to dispense with a separate seal between the housing input part and the fastening part.

The support sleeve serves to support the pushed-in tube from the inside in order to prevent an excessive constriction of the tube as a result of the radial contact pressure of the narrowing holding element which is embodied as a lock washer.

The housing input part and support sleeve form a type of cartridge in which the parts which fixedly hold and seal off the tube which is to be plugged in later, such as the inner annular seal and holding element, are inserted securely and in a captive fashion.

Said cartridge is placed as a unit together with a coaxially placed-on fastening part into an injection mould and is overmoulded with a connecting section at the parting point of the two parts. After the hardening of the overmoulding material, a non-detachable connection is generated between the cartridge and the fastening part.

The close-fitting, resilient insertion of the collar of the support sleeve into the widened end opening of the housing input part prevents a flow of the moulding material into the interior of the cartridge. It is alternatively possible for the fastening part to be formed during the overmoulding by the overmoulding itself.

In one advantageous embodiment of the invention, the outer connecting section produced by the overmoulding or the fastening part produced by the overmoulding is composed of a hardening thermoplastic plastic material, preferably of polyamide.

The use of plastic as a moulding material for the overmoulding has the advantage that further functional elements can also be produced in a cost- effective manner by being simply integrally formed during the injection moulding process. In addition, advantageous fusion with the overmoulded end region of the housing input part takes place if the latter is likewise produced from plastic. A secure connection is thus created.

If the fastening part is composed of metal, it is connected in a form- fitting manner by the moulding material of the connecting section. In a further advantageous embodiment of the invention, the fastening part is composed of metal and has an external threaded section at its free end. The fastening part is advantageously composed of brass.

In a further advantageous embodiment of the invention, the fastening part is formed by the overmoulding process itself and constitutes a plug.

In a further advantageous embodiment of the invention, the collar which is arranged at the end of the support sleeve is composed of two U- shaped wall sections which are aligned counter to one another. In this way, a flexible outer wall part is formed on the collar, by means of which the support sleeve can be securely clipped into the widened end of the housing input part.

In addition, the two U-shaped wall sections create a radial contact face which is aligned towards the seal in the housing input part, which contact face supports said seal.

A further advantage of said arrangement is that an end-side, axially protruding annular flange of the fastening part can be enclosed in the free annular space of the outer U-shaped wall section, and thereby guides the support sleeve in an aligned fashion. With said solution according to the invention, a plug-in hose coupling is created which, with a small number of easy-to-assemble parts and while being of small installation size, permits a secure and simple connection to the tube.

By using plastic as a moulding material for the overmoulding, functional elements can also be produced in a cost-effective manner by being simply integrally formed during the injection moulding process.

The individual parts are compact and less susceptible to mechanical damage.

By means of the invention, it is possible to dispense with guidance of the housing input part through the fastening part, so that the latter can be of smaller construction because it need no longer be locked to the housing input part at the periphery. Said locking action is assumed by the overmoulded connecting section.

The smaller design of the fastening part leads to a considerable saving of the body volume, which is advantageously noticeable in considerably lower costs in particular in the case of fastening parts composed of brass.

The expansion of the connecting section is restricted in order to produce a good connection to the end regions of housing input part and fastening part. This has the advantageous result that the inner seal in the housing input part is situated outside the overmoulded region and is not subjected to any negative action of heat. From WO 2005/022 022 A1 , it is known to connect a metal tube which has an end flange to a tube branch by means of an overmoulded plastic shell. A plug-in hose coupling with its particular problems and its special construction is not disclosed here.

The invention also relates to a method for producing the plug-in hose coupling according to the invention. The method comprises the following steps: a) a holding element in the form of a cutting lock washer is placed into the housing input part against the inner conical support face, b) the sealing ring is placed over the cutting lock washer into the widened inner end region of the housing input part, c) the support sleeve is inserted into the housing input part on that end side which is situated opposite the plug-in opening, and is fixedly clipped into the widened opening by means of the collar, d) the clipped-together modular unit composed of the housing input part and support sleeve is placed together axially with a fastening part and placed into an injection mould, e) in the injection mould, the end regions of the housing input part and fastening part are coated by overmoulding so as to form a connecting section, with the parts being fixedly connected so as to form a modular unit after hardening.

BRIEF DESCRIPTION OF THE DRAWINGS

Two examples of the invention are explained in more detail below on the basis of the drawings, in which: Figure 1 shows the individual parts of the plug-in hose coupling in the predetermined sequence of assembly;

Figure 2 shows the plug-in hose coupling produced from the individual parts shown in Figure 1 ; Figure 3 shows the individual parts of a modified plug-in hose coupling in the predetermined sequence of assembly;

Figure 4 shows the plug-in hose coupling produced from the individual parts shown in Figure 3, with the tube end plugged in.

DETAILED DESCRIPTION OF THE INVENTION

In Figure 1 , for explanation of the assembly of the plug-in hose coupling 1 according to the invention and shown in Figure 2, the individual parts are illustrated schematically in the sequence of assembly. The production steps as far as the complete plug-in hose coupling 1 are indicated schematically by means of process arrows.

The plug-in hose coupling 1 has a housing input part 2 into which, after a sealing ring 10 and a holding element 11 have been placed on, a support sleeve 5 is pushed and clipped in (working arrow A). The structural unit thus formed in step A, a type of cartridge, is placed axially together with a fastening part 4 (working arrow B).

Said combination is placed into an injection mould (not shown here) and is overmoulded with a thermoplastic moulding material around the respective end regions, which face towards one another, of the housing input part 2 and the fastening part 4 so as to form a connecting section 6 in the shape of a hexagon (working arrow C).

After the hardening of the thermoplastic moulding material from which the connecting section 6 has been formed, an annular seal 23 is placed at the underside of the flange 25 of the fastening part 4 (working arrow D) to reach a good tightness to a motor vehicle unit, the plug-in hose coupling 1 according to the invention and illustrated in Figure 2 is finished and can be fastened to a motor vehicle unit.

Figure 2 illustrates the plug-in hose coupling 1 according to the invention in the fully-assembled state as a half-section.

The plug-in hose coupling 1 has a housing input part 2 with a receiving bore 3, which housing input part 2 is non-detachably connected to a fastening part 4, so as to enclose a support sleeve 5, by means of a plastic, form-fitting, outer connecting section 6 (overmoulded portion) which is overmoulded around the ends of the plug-in hose coupling 1 and fastening part 4. The housing input part 2 is composed of plastic, and the fastening part 4 is composed of metal, preferably brass. During a later assembly in the automobile factory, a tube or hose end

7 is pushed in the direction of the arrow 8 into the receiving bore 3 of the housing input part 2.

Arranged concentrically are an annular seal 10 which bears against the inner periphery in the widened end region 9 of the receiving bore 3 and an annular holding element 11 which bears axially against the seal 10 for a tube end 7 which can be plugged into the receiving bore 3.

The holding element 11 is embodied in the form of an open lock washer and is supported with its outer face 12, which is formed like a truncated cone, against an inner conical support face 13 of the housing input part 2, which support face 13 narrows conically counter to the plug-in direction 8 of the tube end 7.

The holding element 11 has encircling cutting edges 14 on the inner periphery.

Arranged in the interior of the receiving bore 3 is the tubular support sleeve 5 which is supported on the fastening part 4 with an annular collar 15 which is concentric and is situated at one end of said support sleeve 5 and has multiple U-shaped deflections, and onto which the tube end 7 can be pushed up to a base flange 16 of the collar 15 in its first U-shaped deflection 17 at the end of the support sleeve 5. Said base flange 16 thus forms an end-side stop 16 for the tube end 7 which is to be pushed in, and lies on an inner shoulder 33 of the fastening part 4, from which an end-side annular flange 18 extends axially and engages into the collar 15 into a second U-shaped deflection 19, with the axial annular flange 18 comprising the radial base flange 16. The base wall 20 of the second U-shaped deflection 19, which is aligned counter to the first U-shaped deflection 17, is supported on an inner shoulder 27 at the end of the housing input part 2 which, in said region, has a larger inner diameter than the receiving bore 3 at the plug-in opening. The outer diameter of the support sleeve 5 is dimensioned such that an annular gap 32 is formed between the outer wall of the support sleeve 5 and the inner wall of the receiving bore 3, into which annular gap 32 the tube end 7 is pushed during the tube assembly. In the interior of the housing input part 2, the holding element 11 which is embodied as a lock washer is arranged in the region of the conical support face 13.

Said lock washer 11 has one cut at the periphery at a point which is not visible here, so that said lock washer 11 can be compressed or expanded radially.

Said lock washer 11 is supported with its outer face 12, which is formed like a truncated cone, against the support face 13 of the housing input part 2, with the outer face 12 and the support face 13 being parallel to one another. The support face 13 and outer face 12 are designed such that the large diameter of the truncated cone points towards the fastening part 4.

Arranged at the inner periphery of the lock washer 11 are two annular cutting edges 14 which have a triangular cross section. In the region of the cutting edges 14, the inner diameter of the lock washer 11 is slightly smaller than the outer diameter of a tube 7 which is to be pushed through the receiving bore 3 into the plug-in hose coupling 1.

The fastening part 4 has a throughflow bore 21 which is aligned with the receiving bore 3.

The fastening part 4 is suitable for attaching the plug-in hose coupling 1 to a component, for example a motor vehicle unit.

For this purpose, the fastening part 4 is composed of metal, preferably of brass, and has a threaded section 22 with which the plug-in hose coupling 1 is screwed into the component.

An annular seal 23 in the underside 24 of an encircling annular flange 25 of the fastening part 4 serves as a seal against the component (not shown here).

After the seal 10 and the holding element 11 are first placed into the housing input part 2, the housing input part 2 with the axially plugged-in support sleeve 5 and the fastening part 4 are joined together in a non- detachable manner by means of overmoulding of the outer connecting section 6 (called "overmoulding portion").

Here, the combination of the individual parts is placed into an injection mould and is overmoulded (injection moulding) with a hardening thermoplastic plastic material, preferably composed of polyamide.

An encircling, axially extending collar 29 is also produced during the overmoulding at the end of the connecting section 6, which collar 29 secures the seal 23 in the underside 24 of the annular flange of the fastening part 4, in which a groove which is open axially towards the free end of the fastening part 4 is formed in this way, in which groove the seal 23 is seated so as to be secured in position with a slight radial load.

The fastening part 4 has a further annular flange 30 which is spaced apart axially from the annular flange 25 which supports the seal 23 on its underside 24.

The plastic material which is injected into the injection mould can thus be well anchored on the fastening part 4. The annular flanges 25 and 30 can be provided on their outer peripheral faces with small projections and/or notches, which further improves an anchoring of the plastic material. The anchoring of the plastic material on the housing input part 2 is secured by means of an encircling lug 31 on the inner end of the housing input part 2.

The connecting section 6 has spanner flats 26 which are formed by the injection moulding process, by means of which spanner flats 26 corresponding tools for screwing the plug-in hose coupling 1 into threaded bores of the component which is to be supplied, a motor vehicle unit, can be engaged.

A plug-in hose coupling 1 which is produced in this way is positionally fixedly screwed into a component which is to be fluidically connected. Said components can be motor vehicle units such as brake valve etc.

The sealing of the screw-in point is obtained by means of pressing-on of the seal 23.

The assembler needs only to handle one uniformed part, the complete plug-in hose coupling 1 which constitutes a pre-produced component, in order to prepare the motor vehicle unit for a hose attachment. The assembly time is drastically reduced.

The connection of the motor vehicle unit which is provided with the plug-in hose coupling 1 to a hose or a plastic tube in order to obtain a fluid connection is obtained by plugging a tube or hose end 7 into the receiving bore 3 of the plug-in hose coupling 1.

When the tube end 7, as it is inserted, reaches the holding element 11 which is embodied as a lock washer, the lock washer 11 is pressed into the plug-in hose coupling 1 and is supported on the seal 10. Here, the lock washer 11 is slightly opened, so that the tube 7 can pass through. After passing the lock washer 11 and the seal 10, the tube 7 is pushed into the annular gap 28 of the collar 15 formed by the first U-shaped deflection 17 until the tube end 7 bears against the stop 16. As a result of the widening of the lock washer 11 , the latter bears with a slight contact pressure against the tube 7.

Said pressure is intensified in that the lock washer 11 is pushed back by the restoring spring force of the seal 10.

Here, the cutting edges 14 dig into the surface of the tube 7. If the tube 7 is pulled back counter to the insertion direction out of the plug-in hose coupling 1 , the lock washer 11 is taken with it.

As a result of the support of the lock washer 11 on the support face 13, the diameter of the lock washer 11 is reduced in the process, and the cutting edges 14 dig deeper into the surface of the tube 7 until the movement comes to a standstill.

The tube 7 is now non-detachably connected to the plug-in hose coupling 1.

Figures 3 and 4 illustrate a modified embodiment of the plug-in hose coupling 1 according to the invention with the tube end 7 plugged in. Identical parts are provided with the same reference numerals as used in the first exemplary embodiment. Modified parts with the same function are denoted by an additional apostrophe.

The combination of the housing input part 2 and support sleeve 5, including the sealing ring 10 and the holding element 11 , is identical to that described in the first exemplary embodiment. The housing input part 2 and support sleeve 5 are composed of plastic material. The holding element 11 which is embodied as a lock washer is composed of metal, preferably brass.

The fastening part 4' is not present as an individual part as the other parts are placed together, which is intended to be illustrated by the arrow

Said fastening part 4' is produced by means of shaped overmoulding only after the placing-in of the cartridge unit, which is formed from the housing input part 2 and the support sleeve 5, with the placing-in of a metallic annular reinforcement part 41 which engages into the collar 15 of the support sleeve 5 (working arrow F).

The plug-in hose coupling V is generated which is illustrated in section in Figure 4 and in which the fastening part 4' is produced in the form of a plug by the overmoulding process.

Said plug 4' is provided retroactively with an outer sealing ring 42 in order to produce a sealing action when plugged into a corresponding receiving opening on a motor vehicle unit.