Method and device for producing a hose nipple

The invention relates to the production of profiled hose nipples. The invention was based on the object of providing a method and an apparatus which allow hose nipples of the type outlined in the introduction to be produced in a simple manner such that the formation of burrs is avoided and there is no reduction in diameter. This object is achieved in that during the forming of pipe portions (1) in the apparatus (2, 7, 9) according to the invention in the region of the subsequent ring-shaped webs (4) of the nipple profile (3), the material of the pipe portion (1), at its outwardly pointing end (4), does not come into contact with the tool in the region of the parting joints (6) of the apparatus (2, 7). This can be realized by additional cavities (14) in the tool (2, 7).

The invention relates to a production method for profiled hose nipples.

In fluid technology, hose nipples are usually used for plugged attachment of a flexible fluid line, for example a rubber hose. Since it is necessary to fix the fluid line on the hose nipple, hose nipples of this kind have an outer profile such that the outer profile can be pushed into the material of the fluid line, for example when the fluid line is being pressed on the hose nipple, with the result that a tight connection of the fluid line on the hose nipple is ensured, said connection being secured against slipping of the fluid line off from the hose nipple.

The hose nipples can be produced in various ways. By way of example, the nipple profile can be produced by turning, grinding, roller burnishing, hammering or pressing.

Machining entails the disadvantage that chips may be produced in the process, which have to be carefully removed or the parts have to be disposed of. Roller burnishing and hammering, like machining, are relatively time-intensive processes, with the machines requiring complex adjustment. The profile is produced in a chipless manner for example by hammering or roller burnishing. This often results in the formation of burrs which may damage a fluid line when the fluid line is being pushed onto the nipple.

WO 1986 00 68 13 A1 discloses a method in which a pipe end is deformed into an intended profiled shape by a reduction in diameter by cold working. In addition to the risk of burrs forming in this method, there is also the disadvantage here that the diameter of the pipe in the region of the nipple is reduced. This leads to a reduced flow in the region of the nipple, and so it may be necessary to make the entire pipe larger.

The invention was based on the object of providing a method which can be used to produce hose nipples of the type outlined in the introduction in a simple manner such that the aforementioned disadvantages are avoided and there is no reduction in diameter.

This object is achieved in that the method comprises the following working steps, specifically:providing a divisible forming tool having at least two tool parts, wherein the tool parts each have at least one cutout, said cutouts forming an elongate cavity when the tool parts are assembled, wherein the cutouts are each profiled in such a way that when the tool parts are assembled, the elongate cavity has a profile of predetermined geometry with radially inwardly projecting ring-shaped webs and radially outwardly pointing ring-shaped grooves,inserting a pipe portion into the elongate cavity,pressing or drawing a forming punch into the pipe portion, wherein the forming punch is designed in such a way that when it is being pressed or drawn into the pipe portion, the diameter of the pipe portion increases and the material of the pipe portion is radially outwardly displaced into the profile of the elongate cavity, and that, in the region of the tool partings, a distance remains between the pipe portion material that is displaced into the radially outwardly pointing ring-shaped grooves of the profile and the tool wall,opening the tool,removing the pipe portion which has been formed into a hose nipple.

Because the diameter of the pipe portion is increased in the method according to the invention, there is no undesired throttling of a volume flow in the region of the hose nipple.

Corresponding harmonization of diameter, wall thickness of the pipe portion, the diameter of the forming punch and the depth of the radially outwardly pointing ring-shaped grooves of the tool profile makes it possible to adjust the material flow such that the material of the pipe portion flowing into the aforementioned grooves is not pressed against the wall of the tool. Therefore, on the finished hose nipple, burrs resulting from the parting of the tool can be found only in the regions in which the material of the pipe portion comes into contact with the tool, that is to say in the profile troughs of the hose nipple in the present case. In this way, the risk of damage to a hose occurring when the hose is being pushed onto the hose nipple is significantly reduced.

The invention was furthermore based on the object of providing an apparatus which allows hose nipples with an outer profile to be produced in a simple, rapid and inexpensive manner while avoiding the aforementioned disadvantages, without reducing in particular the inner diameter in the process.

This object is achieved in that the apparatus comprises at least the following components, specifically:at least one at least two-part forming tool and at least one forming punch, whereinthe forming tool parts each have at least one cutout, and when the forming tool parts are assembled, the cutouts can form at least one elongate cavity which is suitable for accommodating a respective end of a pipe portion with a predetermined geometry, whereinthe elongate cavity has a profile which has radially inwardly projecting ring-shaped webs and radially outwardly pointing ring-shaped grooves, whereinthe radially outwardly pointing ring-shaped grooves have, at their end zone assigned to the outward direction, additional cavities at least in the region of the tool parting, andwherein the at least one forming punch is designed in such a way that it can be pressed or drawn into the pipe portion, wherein the diameter of the forming punch corresponds to the predetermined geometry of the pipe portion in such a way thatwhen the forming punch is being pressed or drawn in, the pipe portion can be deformed to have a diameter greater than its initial diameter, whereby material of the wall of the pipe portion can be pressed outward, wherein the material that is pressed outward engages in the profile of the elongate cavity and can be formed into a shape, which corresponds to the profile, of the pipe portion in such a way that the material comes into contact with the inwardly projecting ring-shaped webs, and the material which is pressed into the outwardly pointing ring-shaped grooves penetrates the ring-shaped grooves in such a way that a distance remains between the material of the pipe portion and the tool as a result of the additional cavities.

An apparatus of this kind has the advantage that there is no reduction in diameter during the forming. The forming with the apparatus according to the invention takes place as cold massive forming, which entails good strength of the produced parts. A decisive factor in such a forming operation is that in spite of the use of a split tool and flash which is inevitably formed on the finished part, this flash is non-critical, since the profile of the tool is matched to the predetermined geometry and the forming punch in such a way that a burr is present only in the profile troughs of the finished part. By contrast, the outer surfaces of the profile webs that are necessary for sealing purposes do not have any flash. By virtue of the fact that, during the forming, the material of the pipe portion can indeed be pressed into the outwardly pointing tool grooves but the additional cavity arranged suitably thereon ensures that there is a distance between the tool and the pressed material in this region, the finished part has no burrs on the ring-shaped profile webs since the formed material of the pipe portion does not come into contact with the parting joints in the tool in this region.

In a refinement of the invention, the apparatus also has a ring-shaped forming tool part which is in the form of a non-split ring, wherein the opening of the ring can be pressed in an axially flush manner onto the pipe portion inserted into the elongate cavity of the split forming tool.

A ring-shaped forming tool part of this kind has the advantage that it can be used to form for example a threading aid on the pipe portion. Because the opening is in the form of a non-split ring, the problem of burr formation does not occur here.

The hose nipple1has a profile3which has ring-shaped webs4and profile troughs5. In the illustration, the line6denotes a parting plane or a parting joint of the apparatus2, the parting plane being illustrated rotated through 90° as a partial longitudinal section of the apparatus2in the lower part of the FIGURE.

In the region of the parting joint6, the profile troughs5have burrs (not illustrated here). By contrast, the webs4do not have any burrs in the region of the parting joint6.

The apparatus2shown in the lower part ofFIG.1has 2 tool halves, of which only one tool half7is shown here as a partial section. Arranged in the end region8of the apparatus2is a further tool part9which has an opening10of closed ring-shaped form which opens conically in the direction of the inserted hose nipple1.

The tool halves7have a virtually tooth-like profile11in section. Inwardly projecting teeth12alternate with radially outwardly pointing grooves13in an axial direction. Arranged at the respectively radially external end of the grooves13is a respective cavity14which is present only in the region of the parting joint of the tool halves.

During the forming of the hose nipple1, which has already been carried out in this illustration, the original diameter of the pipe-like hose nipple1was increased, wherein the radial extent of the hose nipple1is delimited by the tool halves7and the further tool part9. In this case, the increase in diameter is determined in advance such that the material of the hose nipple1can indeed be pressed into the profile11of the apparatus2but a distance between the hose nipple1and the apparatus2remains in the region of the cavities14. This means that, in this region of the parting joint, the ring-shaped webs4do not come into contact with the tool at their axial end and thus no burrs can be produced in this region either. In this way, the crucial load-bearing webs4remain free of burrs, with the result that a tube (not shown here) capable of being pushed on can be pushed onto the hose nipple1without being damaged.

This is further improved by the formation of a burr-free run-on bevel15by means of the tool part9.

LIST OF REFERENCE DESIGNATIONS

Part of the Description

1Hose nipple2Apparatus3Profile of the hose nipple14Ring-shaped webs of the profile35Profile troughs of the profile36Parting joint7Tool half of the apparatus28End region of the apparatus29Further tool part10Conical opening of the tool part911Tooth-like profile of the tool half712Teeth of the profile1113Grooves of the profile1114Cavities at the axially outer end of the grooves1315Run-on bevel