EP4144456A1 - Method for producing a high pressure hydraulic line - Google Patents

Abstract

In the production of a high-pressure hydraulic line, a connection fitting is attached to the end of a high-pressure hose, with a section of a high-pressure hose (3) and a connection fitting to be joined to it, comprising a nipple (4) and a compression sleeve (5), being provided, the connection fitting on an end section of the high-pressure hose (3) is placed, the line blank (2) produced in this way is placed in a program-controlled radial press (1) and a joining operation is carried out to form a tight connection between the high-pressure hose (3) and the connection fitting in the radial press (1) by plastic Deformation of the compression sleeve (5) is carried out when the pressing tool (6) is force-closed according to a pressing program (P). When the pressing tool (6) is closed, the geometric configuration of the pressing tool (6) is recorded when the pressing jaws (7) are placed on the pressing sleeve (5); and the pressing program (P) run through by the radial press (1) is determined by specific adaptation of a basic program (B) stored in the radial press (1), taking into account the configuration of the pressing tool ( 6) formed.

Description

The present invention is in the technical field of manufacturing high pressure hydraulic lines. In particular, the invention, as specified in detail in the preamble of claim 1, is in the field of such methods in which a high-pressure hose and a connection fitting comprising a nipple and a compression sleeve are permanently joined to one another - with plastic radial deformation of the sleeve thereof, the plastic radial deformation is carried out using a program-controlled radial press with a pressing tool comprising a plurality of pressing jaws arranged around a pressing axis, namely by providing a section of the high-pressure hose and the connection fitting to be joined with it, the connection fitting being placed on an end section of the high-pressure hose that is produced in this way Line blank is inserted into the program-controlled radial press, the compression sleeve coming to rest in the open pressing tool of the radial press, and a joining operation to form a tight connection of the high-pressure hose is carried out with the connection fitting in the radial press by plastic deformation of the press sleeve when the press tool is force-closed according to a press program. The sealing surface is usually the inner surface of the high-pressure hydraulic hose that is pressed more or less tightly against the nipple by means of the compression sleeve.

With regard to such methods, but in particular to the radial presses used in these methods, there is a wide range of prior art. As far as aspects of the procedure are concerned, reference should be made to, for example, the US 5,651,282 A , the WO 2010/120373 A2 , the WO 2016/162890 A1 , the DE 10 2018 115 750 B3 and the US 6,237,204 B1 . For example, about aspects of the radial presses used DE 10 2014 012 485 B3 , DE 10 2009 057 726 A1 , DE 10 2011 015 770 A1 , DE 199 12 976 A1 , DE 20 2016 100 660 U1 , DE 41 35 465 A1 and WO 2001/033675 A1 (concerning radial presses in yoke press design), the DE 10 2017 119 403 A1 , DE 10 2016 106 650 A1 and EP 1 302 255 A1 (relating to radial presses in hollow piston press design), the EP 239 875 A2 , DE 10 2011 015 654 A1 and WO 1981/003456 A1 (regarding radial presses in pressure plate press design) and the DE 199 40 744 A1 , WO 2002/024374 A1 , DE 10 2012 025 134 A1 , DE 298 24 688 U1 , EP 17 660 A1 and EP 2 786 817 B1 (relating to radial presses in other constructions).

The quality of the connection between the connection fitting and the high-pressure hose is extremely important from the point of view of work and operational safety. A failure of the connection (so-called "hose tearing") poses a very significant risk to the health or physical integrity of people in the area, not to mention property damage (e.g. environmental damage caused by released hydraulic fluid). The security against hose tearing in high-pressure hydraulic lines manufactured according to the generic manufacturing method is a special one represents a challenge, is related to several technical features of the parts/components and joining technology used. On the one hand, the high-pressure hose is flexible, i.e. the wall of the hose - to be clamped between the nipple and the compression sleeve - can be elastically compressed in the radial direction, although excessive compression leads to damage to the hose, which in turn leads to premature failure of the pressurized high-pressure hydraulic line can result. And the high-pressure hydraulic hose can - in contrast to rigid pipes, which are connected by means of a fitting pressed onto the outside and sealed against the outer surface of the pipe - move to the side, which increases the risk of the hose tearing out.

Against the background of the problems set out above, there is a permanent need for measures that are suitable for further improving the generic method discussed here for the production of high-pressure hydraulic lines, particularly with regard to the reliability of the hydraulic lines produced.

The present invention has set itself the task of making a contribution in the above respect.

This object is achieved according to the invention in that the geometric configuration of the pressing tool is recorded when the pressing jaws are placed on the pressing sleeve in generic methods for producing a high-pressure hydraulic line when the pressing tool is closed and that by the radial press The press program that is run through is formed by specific adaptation of a basic program stored in the radial press, taking into account the configuration of the press tool recorded when the press jaws are placed on the press sleeve. According to the present invention, the pressing program for the high-pressure hydraulic line to be manufactured, which the radial press runs through for the plastic deformation of the pressing sleeve for the purpose of tightly joining the connection fitting to the high-pressure hose, is determined individually during the ongoing manufacturing process, namely by individual, specific adaptation a basic program stored in the radial press, taking into account the configuration of the press tool that it assumes when the press jaws are placed on the press sleeve. The relevant geometric pressing tool configuration used for the individual adaptation of the basic program - for the components used in each case (high-pressure hydraulic hose and connection fitting) of the relevant high-pressure hydraulic line - is used when the pressing tool is closed at the moment when the pressing jaws are placed on the pressing sleeve recorded. In this way, even comparatively small deviations in the dimension of the compression sleeve from the nominal dimension, which are definitely still within the permissible tolerances, can be recorded and taken into account when forming/calculating the compression program to be used for the individual compression process. The corresponding consideration of the exact starting dimensions of the sleeve of the connection fitting, ie a certain individually recorded oversize or undersize compared to the nominal size, can result in particular in a corresponding Record the shift in the final dimension specified via the individual pressing program for the respective pressing process.

With an individual adaptation of the press program related to the respective individual workpiece or an individual group of workpieces (see below), high-pressure hydraulic lines with very good reproducibility and consequently of very good quality can be produced in a surprisingly simple way with comparatively little effort.

From the following explanations, in particular those of the exemplary embodiment illustrated in the drawing, it can be seen that the line blank is in contact with a pressing jaw from the start of the closing of the radial press, namely can rest on it. In this regard, it should be emphasized that, within the scope of the invention, the specific adaptation of the basic program is based on the placement of “the pressing jaws” (plural!) on the pressing sleeve. In other words, what is decisive is the geometric configuration of the pressing tool at the moment when at least two pressing jaws (preferably opposite one another) are in contact with the pressing sleeve.

In a particularly preferred embodiment of the invention, the specific adaptation of the basic program stored in the radial press consists in determining the specific gauge block for the force closing of the press tool while simultaneously influencing the force-displacement characteristic curve run through up to that point. In this Starting from the basic program stored in the machine control, both the final dimension for the force closing of the press tool and the progression (e.g. the local gradient) of the force-displacement characteristic depending on the initial dimension of the sleeve of the connection fitting can be specific be modified individually. This takes account of the fact that a dimensional deviation can often also be accompanied by a deviation in the material properties, to which a suitable modification of the compression characteristic curve can be used to react. However, under boundary conditions that are typical in practice, the advantages that can be achieved by the invention can generally also be realized to a pronounced extent if the specific adaptation of the basic program stored in the radial press "only" consists of a determination of the specific final dimension for the force closing of the pressing tool, however, there is no additional influence on the force-displacement characteristic curve that has been run through up to that point.

According to another preferred development of the invention, the configuration of the pressing tool is recorded directly on the pressing tool when the pressing jaws are placed on the pressing sleeve. In this sense, for example, the distance between two diametrically opposite pressing jaws can be monitored when the pressing tool is closed using suitable sensors known as such, and the pressing jaw distance existing at the moment the pressing jaws are placed on the pressing sleeve can be used for the specific adaptation of the pressing program to be run through.

Alternatively, depending on the individual type of radial press, it can also be advantageous to indirectly detect the configuration of the pressing tool when the pressing jaws are placed on the pressing sleeve by detecting the configuration of a drive unit acting on the pressing tool. In this sense, for example, the exact geometric configuration of an actuator belonging to the drive unit (e.g. the position of the piston of a hydraulic cylinder) or a transmission element can be monitored when the pressing tool is closed and the configuration of the actuator or .

A particularly preferred development of the method according to the invention is characterized in that, for a production batch comprising several matching high-pressure hydraulic lines, the specific adaptation of the basic program stored in the radial press, taking into account the configuration of the pressing tool recorded when the pressing jaws are placed on the pressing sleeve, is specifically individual for the respective individual pressing process takes place. It is therefore characteristic of this development that for all of the "same" high-pressure hydraulic lines to be manufactured within a production lot, there is not a uniform compression gauge (e.g. determined individually during the first compression process from the production lot), but this individually specific for the respective individual pressing process is determined. This way you can optimally utilize the potential created in the present invention.

In particular, when the initial dimensions of the compression sleeves of the connection fittings differ to a relevant extent from one production batch to the next, but the compression sleeves within a production batch have the greatest degree of uniformity in terms of their actual dimensions, the quality advantages described and achievable by the present invention result of the high-pressure hydraulic lines produced, even if, according to an alternative preferred embodiment of the invention, for a production batch comprising several matching high-pressure hydraulic lines, the specific adaptation of the basic program stored in the radial press, taking into account the configuration of the pressing tool recorded when the pressing jaws were placed on the pressing sleeve takes place in the first pressing of the production lot and is retained for subsequent pressings.

It should be pointed out that for the present invention and the advantages associated with it, it is clearly irrelevant whether the high-pressure hose is more or less flexible. In this respect, such pipes that can be used for the production of high-pressure hydraulic lines, which are not flexible within the scope of their intended use or do not need to be flexible, but rather are generally referred to as "rigid", also constitute "high-pressure hoses" within the meaning of the present invention Invention. The process and characteristics of this Structural features can also be used in various other, comparable joining applications, which are also characterized by the radial deformation of at least one component of a pair of components prepared to form a blank, such as shaft connections, isolator connections, anchor connections and the like .

Fig. 1

eine zur Durchführung des erfindungsgemäßen Verfahrens geeignete und hergerichtete Radialpresse; und

Fig. 2

veranschaulicht die unter Verwendung der Radialpresse nach Fig. 1 erzielbare Verfahrensführung.

The present invention is explained in more detail below using a preferred exemplary embodiment illustrated in the drawing. while showing

1

a radial press suitable and prepared for carrying out the method according to the invention; and

2

illustrates that using the radial press 1 achievable procedure.

In the 1 Radial press 1 shown as an example corresponds to that according to the structure and function of the DE 41 35 565 A1 . Unless otherwise stated in the following explanations, it is therefore identical to the prior art that is sufficiently known and established in practice. To avoid unnecessary explanations, the content of the DE 41 35 565 A1 referenced, the disclosure content of which is incorporated in full into the content of the present application by reference.

The process status immediately before the start of the pressing process is illustrated. A line blank 2, which - in the usual way - a section of a high-pressure hose 3 and an end portion which is attached to the same and has a nipple 4 (inserted on the inside of the high-pressure hose 3) and a compression sleeve 5 (on the outside of the high-pressure hose 3) which has a connection fitting, is inserted into the opened compression tool 6 in such a way that the compression sleeve 5 rests on the lower compression jaw 7u rests. Also shown is an operating, control and monitoring unit 8 associated with the radial press 1 , which controls both the electric motor 10 driving the hydraulic pump 9 and the valve unit 11 . In this respect, too, the radial press 1 shown is still in the area of the generally known prior art, even if this is in the DE 41 35 565 A1 is not explicitly stated.

The radial press 1 is modified according to 1 compared to the one after the DE 41 35 565 A1 to the extent that it--instead of a combination of adjusting spindle and microswitch used for limit switching--has a pickup (distance sensor) 14 that detects the distance between the upper yoke 12 and the lower yoke 13 relative to one another. The distance signal generated by this sensor 14 is switched to the operating, control and monitoring unit 8 via a signal line 15 . Furthermore, the base jaw 16 of the upper pressing jaw 7o is equipped with a deformation sensor 17 (e.g. in the form of a strain gauge 18 attached to the face of the relevant base jaw 16). The signal generated by the deformation sensor 17 is also switched to the operating, control and monitoring unit 8 via a signal line 19 .

If the operator of the radial press 1 initiates the pressing process, the pressing tool 6 closes around the workpiece, d. H. around the line blank 2. At the beginning of the pressing process, the pressing program corresponds to a basic program stored in the operating, control and monitoring unit 8 and valid for the parts to be joined.

The pressing sleeve 5 resting on the lower pressing jaw 7u is increasingly approaching the upper pressing jaw 7o. The moment the latter touches down on the press sleeve 5, the load and tension situation in the upper press jaw 7o changes, ie in particular (also) in its base jaw 16. This is - via a corresponding induced deformation of the base jaw 16 in question - by means of the deformation sensor 17 is detected. The value of the distance between the upper yoke 12 and the lower yoke 13 provided by the pickup 14 at this moment is used as a reference value for the subsequent power pressing. In this case, a pressing program is run through, which is based on the basic program stored in the operating, control and monitoring unit 8 and valid for the pressing of the selected combination of high-pressure hose and connection fitting, whereby this, however, takes into account the precise configuration of the pressing tool 6 that this when placing the upper press jaw 7o on the press sleeve 5 and which is detected by the pickup 14 is specifically adapted for the individual workpiece. In particular, a deviation from the actual size of the Compression sleeve 5 considered by the nominal size in terms of a shift in the final size of the compression.

This is illustrated in 2 on the basis of a (schematic, greatly exaggerated) diagram which shows the distance D of the two yokes 12, 13 from one another, which is decisive for the geometric configuration of the pressing tool 6, over time t, specifically for the three phases closing I, holding II and opening III. This is based on the operation of the radial press 1 with a hydraulic pump 9 designed as a constant feed pump, so that the pressing tool is closed by applying pressure to the two press cylinders 20 and the pressing tool is opened by applying pressure to the return stroke cylinder 21, each at a constant speed. As a result of the significantly smaller cross section of the return stroke cylinder 21 compared to the sum of the areas of the two press cylinders 20, the pressing tool 6 of the radial press 1 is opened—at the same delivery rate of the hydraulic pump 9—however at a significantly higher speed than when it is closed.

According to the basic program B stored in the operating, control and monitoring unit 8 and designed for a nominal diameter D _N of the compression sleeve 5, the radial press 1 closes—from an initial dimension D ₀ — to a nominal press gauge D _NE . Here it is switched to "hold" for the hold time t _HN . After the end of the holding time, the radial press 1 is completely opened back to the initial dimension D ₀ .

If the compression sleeve 5 to be compressed in the individual compression process has an actual diameter D _I that differs from the nominal diameter D _N , the compression program is modified. If, for example, the actual diameter D _I of the press sleeve 5 is greater than the nominal diameter D _N in the sense explained above, the press gauge for the press program P actually run through is shifted from the nominal press gauge D _NE to the (correspondingly larger) press -actual gauge D _IE . The dimension of this adaptation of the basic program B corresponds to the difference between the actual diameter D _I and the nominal diameter _DN of the compression sleeve 5, so that for the actually compressed compression sleeve 5 the deformation dimension ΔD _I corresponds to that to which the - on compression sleeves that have the nominal dimension D _N comply, related - basic program B is designed (ΔD _N ).

In the case of press sleeves 5 with undersize, the above applies in a corresponding manner with the result that the actual press gauge D _IE is smaller than the nominal press gauge D _NE .

in the in 2 illustrated case, the holding time is not changed by the adaptation of the basic program B; the holding time t _HI actually observed during pressing therefore corresponds to the holding time t _HN provided according to the basic program B. Obviously, however, an adaptation can also be made with regard to the holding time, for example such that when pressing workpieces that deviate from the design case on which the basic program B is based, an increased holding time t _HI is always maintained as a precaution.

After the above explanation, a person skilled in the art will readily understand the corresponding implementations of the present invention on differently designed radial presses, in particular on hollow piston presses and pressure plate presses (see above), on radial presses with drives other than hydraulic drives, on radial presses with variable closing speeds (e.g. by using a servo pump or proportional valves), in radial presses with a separate rapid closing drive, etc. In the same way, the implementation of the invention is readily apparent to a person skilled in the art in such a way that the configuration of the pressing tool is not detected directly on the pressing tool itself when the pressing jaws are placed on the pressing sleeve, rather it is recorded indirectly by directly recording the configuration of a drive unit acting on the pressing tool.

Claims (7)

Method for producing a high-pressure hydraulic line by attaching a connection fitting at the end of a high-pressure hose, comprising - Providing a section of a high-pressure hose (3) and a connection fitting to be joined to this, comprising a nipple (4) and a compression sleeve (5), - Place the connection fitting on an end section of the high-pressure hose (3), - Insertion of the line blank (2) produced in this way in a program-controlled radial press (1), with the pressing sleeve (5) in the open pressing tool (6), comprising a plurality of pressing jaws (7) arranged around a pressing axis, of the radial press (1st ) comes to rest - Carrying out a joining operation to form a tight connection between the high-pressure hose (3) and the connection fitting in the radial press (1) by plastic deformation of the press sleeve (5) when the press tool (6) is force-closed according to a press program (P), characterized in that - When the pressing tool (6) is closed, the geometric configuration of the pressing tool (6) is recorded when the pressing jaws (7) are placed on the pressing sleeve (5) and - The pressing program (P) run through by the radial press (1) is formed by specific adaptation of a basic program (B) stored in the radial press (1), taking into account the configuration of the pressing tool recorded when the pressing jaws (7) are placed on the pressing sleeve (5). (6). Method according to Claim 1, characterized in that the configuration of the pressing tool (6) is detected directly on the pressing tool (6) when the pressing jaws (7) are placed on the pressing sleeve (5). Method according to Claim 1, characterized in that the configuration of the pressing tool (6) when the pressing jaws (7) are placed on the pressing sleeve (5) is detected indirectly by directly detecting the configuration of a drive unit acting on the pressing tool (6). Method according to one of Claims 1 to 3, characterized in that for a production lot comprising several matching high-pressure hydraulic lines, the specific adaptation of the basic program (B) stored in the radial press (1) takes into account the when the pressing jaws (7) are placed on the pressing sleeve (5) detected configuration of the pressing tool (6) is carried out individually for the respective pressing process. The method according to any one of claims 1 to 3, characterized in that for a plurality of matching high-pressure hydraulic lines comprehensive production batch, the specific adaptation of the basic program (B) stored in the radial press (1) takes place, taking into account the configuration of the pressing tool (6) recorded when the pressing jaws (7) are placed on the pressing sleeve (5), during the first pressing process of the production batch and for subsequent ones pressing operations is maintained. Method according to one of Claims 1 to 5, characterized in that the specific adaptation of the basic program (B) stored in the radial press (1) in a determination of the specific final dimension for the force closing of the pressing tool (6) without influencing the force passed through up to that point -path characteristic exists. Method according to one of Claims 1 to 5, characterized in that the specific adaptation of the basic program (B) stored in the radial press (1) involves a determination of the specific final dimension for the force closing of the pressing tool (6) while at the same time influencing the program run through up to that point There is a force-displacement characteristic.

Images