Method for producing a high-pressure hydraulic line and radial press for carrying out said method

Abstract

In a method for producing a high-pressure hydraulic line, a connection fitting (4) is arranged on the end side of a multi-layer high-pressure hose (5) having at least one reinforcement layer (6, 7) by providing a section of the reinforced high-pressure hose (5) and a connection fitting (4) to be joined to the section, placing the connection fitting (4) on the end section of the high-pressure hose (5) and performing a joining operation to form a sealed connection between the high-pressure hose (5) and the connection fitting (4). The quality of the connection between the connecting fitting (4) and the hydraulic hose (5) is determined by applying an electrical test signal to at least one connector (12; 16) of a test device (18) having two connectors (12, 16), wherein a first connector (12) is electrically and / or magnetically coupled to the connecting fitting (4) and a second connector (16) is contactlessly electrically and / or magnetically coupled to a reinforcement layer (6) of the high-pressure hose (5) or at least one of the reinforcement layers (6, 7) of the high-pressure hose, detecting an electrical response signal generated in the test device and comparing the response signal with a setpoint value range for the relevant high-pressure hose-connection fitting pairing stored in a memory of the test device (48).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a high-pressure hydraulic line. More specifically, the present invention relates to a method for manufacturing a high-pressure hydraulic line by attaching a connection fitting to the end of a multilayer high-pressure hose having at least one reinforcement layer. The method comprises the following steps: providing a section of the reinforced high-pressure hose and a connection fitting to be joined to the section, placing the connection fitting on the end section of the high-pressure hose, and performing a joining operation to form a sealed connection between the high-pressure hose and the connection fitting. Furthermore, the present invention relates to a radial press suitable for carrying out this manufacturing method. Background Art

[0002] High-pressure hydraulic lines are manufactured on a large scale in the manner described above, with connector fittings typically being joined to both ends of a hose section. A very widely used method for joining the (corresponding) connector fitting to the hose section at the (relevant) end is to radially press the press sleeve of the corresponding connector fitting so that the hose, which is usually pre-stripped externally and / or internally, is firmly, permanently, and media-tightly pressed into the annular gap between the press sleeve (surrounding the hose externally) and the threaded sleeve (pressed into the hose interior). This is also known from the prior art, for example, radial presses are suitable for this purpose (see, for example, patent document DE 28 44 475 A1).

[0003] The quality of the connection between the connection fitting and the hose section is extremely important in terms of work safety and operational reliability. If the hose section becomes disconnected from the connection fitting during high-pressure operation, this can pose a significant risk to the health or physical integrity of nearby personnel, not to mention property damage and environmental damage caused by the released hydraulic fluid. Summary of the Invention

[0004] In this context, the technical problem to be solved by the present invention is to help improve the safety of the high-pressure hydraulic pipeline manufactured in the above manner during high-pressure operation.

[0005] According to the invention, the technical problem is solved by determining the quality of the connection between the connecting fitting and the high-pressure hose, comprising

[0006] - applying an electrical test signal to at least one connection of a test device having two connections, a first connection being electrically and / or magnetically coupled to a connecting fitting and a second connection being electrically and / or magnetically coupled contactlessly to a reinforcement layer of a high-pressure hose or at least one of the reinforcement layers of the high-pressure hose,

[0007] - detecting an electrical response signal generated in said testing device,

[0008] - comparing the response signal with a setpoint value range for the relevant high-pressure hose-connection fitting pair stored in a memory of the testing device,

[0009] The present invention utilizes several insights. Firstly, the present invention utilizes the knowledge that there is a correlation between the quality of the connection between a high-pressure hose section and a connection fitting and the contact properties between the high-pressure hose's reinforcement layer (or at least one of the reinforcement layers) and the connection fitting. The quality of the connection, i.e., the safety against disconnection of the high-pressure hose from the connection fitting or similar malfunctions, is reflected in an electrical response signal generated in a test device having two connectors. The test device is used to apply an electrical test signal to the relevant region of the high-pressure hydraulic line. A first connector of the test device is electrically and / or magnetically coupled to the connection fitting, and a second connector of the test device is electrically and / or magnetically coupled to the high-pressure hose's reinforcement layer (or at least one of the reinforcement layers). The second connector of the test device is contactlessly coupled to the reinforcement layer (or at least one of the reinforcement layers), thereby ensuring that the integrity of the other layers of the high-pressure hose that surround the relevant reinforcement layer externally and / or internally is not compromised, i.e., the high-pressure hose remains intact. In the test device, the response signal is compared with a setpoint range, which is stored in the test device's memory as an independent setpoint range applicable to the specific high-pressure hose-connection fitting pair in question. Depending on whether the response signal lies within or outside the setpoint range, the tested end section of the high-pressure hydraulic line is classified as good or poor in terms of the quality of the connection between the corresponding connection fitting and the high-pressure hose section.

[0010] The electrical test signal can be oscillated, for example, with different frequency characteristics and advantageously selected such that the magnetic resistance and / or impedance and / or resistance of the section of the high-pressure hydraulic line to be tested, located between the two connections, can be inferred from the detected electrical response signal. For this purpose, the degree or area of ​​contact between the connection fitting and the at least one reinforcement layer plays a role, which, in many common connection fittings, in turn depends in particular on the penetration depth of the profile of the press sleeve into the or at least one reinforcement layer.

[0011] Other production defects that influence the electrical response signal induced by the electrical test signal can also be detected. This includes, in particular, an insertion depth of the high-pressure hose below the specified insertion depth into the connection fitting, such that only a portion of the profile of the extrusion sleeve contacts the or one of the reinforcement layers. However, the method according to the present invention can also detect irregular stripping of the high-pressure hose to remove material externally and / or internally in the area of ​​subsequent connection to the connection fitting (e.g., too short), as well as incorrect crimp dimensions, incorrect high-pressure hose-connection fitting combinations, and abnormal conditions of the reinforcement layer (e.g., corrosion or damage). Because different individual production defects can be reflected in different characteristic deviations of the response signal from the response signal generated in a properly manufactured high-pressure hydraulic line, a detailed analysis of the response signal can not only determine whether the tested high-pressure hydraulic line meets the standards with respect to the quality of the connection between the connection fitting and the hydraulic hose, but can even, in the case of any deviations, infer the type of production defect. It should be noted that within the scope of the present invention, it is entirely possible to analyze multiple response signals, for example, disturbances in the magnetic field caused by a workpiece subjected to the test signal.

[0012] It should be noted that the applicability of the present invention is by no means limited to methods for producing high-pressure hydraulic lines using connection fittings with extrusion sleeves that can be plastically deformed by a radial press. Other connection fittings, in particular so-called "reusable fittings," can be used within the scope of the present invention. Furthermore, it should be noted that the stated specification of a test device having two connections is not to be construed as limiting the device to having only two connections. If the present invention is used in a method for producing branched high-pressure hydraulic lines, the test device can also have more than two connections, for example, three connections.

[0013] A first preferred embodiment of the invention is characterized in that, for coupling the first terminal of the test device to the connection fitting, a contact probe is placed on the connection fitting in order to establish galvanic contact between the contact probe and the connection fitting. This achieves particularly high reproducibility while being simple to implement.

[0014] Also advantageous with regard to high reproducibility is that, according to another preferred embodiment of the present invention, the second connector of the test device is electrically or magnetically coupled to the connected fitting in a contactless manner on at least one reinforcement layer adjacent to the connected fitting, i.e., at a distance from the connecting fitting of no more than three times the diameter of the high-pressure hose. It is particularly advantageous if the second connector of the test device is electrically or magnetically coupled to the connecting fitting in a contactless manner on at least one reinforcement layer in close proximity to the connecting fitting.

[0015] Two methods have been demonstrated for contactless electrical or magnetic coupling of the second connector of the test device to the at least one reinforcement layer: capacitive coupling and inductive coupling. Which of these options is preferred in each case depends, in particular, on the individual design of the high-pressure hose, in particular the properties of the at least one reinforcement layer and the other layers. Whether the contactless electrical or magnetic coupling of the second connector of the test device to the at least one reinforcement layer is effected from the outside or the inside of the high-pressure hose may also be influential, although from the inside remains an exception.

[0016] The method according to the invention can be used particularly advantageously in conjunction with a production method for high-pressure hydraulic lines in which, before the connection fitting is placed on the end section of the high-pressure hose, the high-pressure hose is stripped on the inside and / or outside at the end to at least partially expose the or at least one metallic reinforcement layer. This is because stripping the high-pressure hose here creates favorable conditions for good reproducibility of the test.

[0017] According to another advantageous embodiment of the invention, the invention is used in conjunction with a method for producing a connecting fitting for a high-pressure hydraulic line using a screw connection and a press sleeve, wherein:

[0018] The connecting fitting is arranged on the high-pressure hose in such a way that a screw connection extends from the inside into the high-pressure hose and the high-pressure hose enters into the annular gap between the screw connection and the squeeze sleeve, and

[0019] During the joining operation of the tubular hydraulic line thus formed, the tubular hydraulic line is introduced into a radial press having a pressing tool with a plurality of pressing jaws by placing a pressing sleeve in the pressing tool and subsequently radially pressing the pressing sleeve, thereby reducing the clear width of the annular gap of the connecting fitting.

[0020] It is particularly advantageous to determine the quality of the connection between the connecting fitting and the high-pressure hose in the radial press. It is particularly advantageous to determine the quality of the connection between the connecting fitting and the high-pressure hose before the radial pressing is completed. This is because it is possible to communicate with the control device of the radial press in such a way that the radial pressing of the press sleeve, in particular the end of the radial pressing, is controlled based on a signal from the testing device. Quality monitoring carried out in this way, already during the ongoing production process, and which can specifically influence the remaining operation of the production process, is particularly advantageous in terms of efficiency, as it reduces scrap.

[0021] In the aforementioned embodiment of the method according to the present invention, the present invention also includes a radial press suitable for carrying out the method, comprising an extrusion tool having a plurality of extrusion bodies arranged about an extrusion axis and movable radially relative to the extrusion axis by a drive unit, and a testing device having two connections, wherein the first connection is provided for electrical and / or magnetic coupling to a connecting fitting, and the second connection is provided for contactless electrical and / or magnetic coupling to the one or at least one reinforcing layer of a high-pressure hose of a tubular hydraulic line. The connection of the testing device can in particular be arranged on one of the extrusion bodies of the extrusion tool. However, a radial press designed accordingly, i.e., suitable for carrying out the aforementioned method according to the present invention, is not limited in its scope of application to this method. Rather, the press can also be advantageously used, for example, to join multiple components together by radial extrusion to produce insulators, CFRP shafts, and other workpieces.

[0022] However, to avoid misunderstandings, it should be emphasized that quality monitoring during the above-described process is by no means mandatory. Rather, it is also contemplated within the scope of the present invention to remove the hydraulic line from the radial press and only then perform a quality check. In particular, within this scope, the hydraulic line removed from the radial press can be placed in a (separate) pressure test bench, where the quality of the connection between the connector and the high-pressure hose can be determined. This also applies to determining the quality of the connection between the connector and the high-pressure hose in conjunction with cleaning the hydraulic line in a cleaning device.

[0023] If the quality of the connection between the connecting fitting and the high-pressure hose is determined in a pressure test bench within the scope described above, the quality of the connection between the connecting fitting and the high-pressure hose is preferably determined using a test medium (air, gas, water, oil or the like) under different pressures. This is because possible deviations in the response signal under different pressure conditions can also be used to draw conclusions about the condition of the high-pressure hydraulic line being tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be explained in more detail below based on a preferred embodiment of a radial press which is schematically shown in the drawing and which is suitable for carrying out the method. The drawing shows an axial section through such a radial press. DETAILED DESCRIPTION

[0025] Apart from the points and features explained below, the radial press 1 according to the illustrated embodiment corresponds non-limitingly to the radial press according to DE 2844 475 A1. Figure 1 In order to avoid unnecessary repetition, reference is therefore made to patent document DE 28 44 475 A1 with regard to the structure and construction, technical details and functionality of the radial press.

[0026] The radial press 1 is shown with a pressure jaw attachment 3 (replaceably attached to a pressure jaw 2); the entirety of the pressure jaw 2 and the pressure jaw attachment 3 attached thereto forms the pressure body P. For the sake of clarity, a detailed view of the connection of the pressure jaw attachment 3 to the pressure jaw 2 has been omitted. For this purpose, the pressure jaw attachment can typically have, for example, a pin that engages in a corresponding receptacle formed on the pressure jaw 2 (see, for example, also patent document DE 201 09212 U1).

[0027] Furthermore, the use of the radial press 1 for pressing the end side of the connection fitting 4 onto the high-pressure hose 5 is shown. The high-pressure hose 5 here has two reinforcement layers 6, 7, wherein the outer reinforcement layer 6 is formed in the conventional manner from a metal mesh. The connection fitting 4 also comprises a screw connection 8 and an extrusion sleeve 9 in the conventional manner. The extrusion sleeve has a plurality of annular clamping projections 10 on its inner circumference. The section 11 of the screw connection 8 to be inserted into the high-pressure hose 5 itself has a surface shaped in the conventional manner. In the region of the high-pressure hose 5 into which the connection fitting 4 is to be inserted, i.e. into the annular space between the extrusion sleeve 9 and the section 11 of the screw connection 8, the high-pressure hose is stripped on its outer side, more precisely down to the outer reinforcement layer 6.

[0028] All of this is common and sufficiently known to the person skilled in the art so that no further explanation is required.

[0029] As indicated by the lower pressing jaw attachment 3u, a first connection 12 is embedded in (at least) one of the pressing jaw attachments 3, more precisely close to a pressing surface 13 of the relevant pressing jaw attachment 3u intended for contact with the pressing sleeve 9 of the connecting fitting 4. Thus, by suitable electrical loading of the first connection 12, it is possible to inductively couple the first connection to the pressing sleeve 9.

[0030] The second connection 16 is attached to the lower squeeze jaw attachment 3u via a holding device 15 at its end face 14 facing the high-pressure hose 5, specifically so that the second connection and the surface 17 of the high-pressure hose 5 lie closely opposite one another. Thus, by suitable electrical loading of the second connection 16, it can be inductively coupled to the outer reinforcement layer 6 of the high-pressure hose 5.

[0031] The first connection 12 and the second connection 16 are components of a test device 18, which also includes a control module 19. The two connections 12 and 16 are electrically connected to the control module 19 via a line 20 and, for the exchangeability of the extrusion jaw attachment 3, via two plug-in transitions 21. Via this electrical connection, the first connection 12 and / or the second connection 16 are acted upon by the control module with an electrical test signal according to an individual test program.

[0032] The first connector 12 and / or the second connector 16 then function as receivers according to a customized test program. The electrical response signal generated in the test device when at least one of the connectors 12 and 16 is used as a receiver is also compared with a nominal value range for the specific high-pressure hose-connection fitting pairing stored in the test device's memory. If the actual response signal falls within the bandwidth of the nominal value range, the extrusion, and therefore the workpiece, is considered intact. Otherwise, depending on the extent and orientation of the deviation, either further processing (re-extrusion) is performed in the radial press or the workpiece is rejected as defective.

[0033] It will be seen that the explanation of the invention using a radial press configured according to the invention in accordance with patent document DE 28 44 475 A1 is purely exemplary and that the invention can be implemented in a similar manner in radial presses operating according to other concepts, such as so-called "yoke presses" in accordance with patent document DE 202016 100 660 U1 and the other prior art cited therein.

Claims

1. A method for producing a high-pressure hydraulic line for attaching a connection fitting (4) to the end side of a multilayer high-pressure hose (5) having at least one reinforcement layer (6, 7), the method comprising - providing a section of reinforced high-pressure hose (5) and a connecting fitting (4) to be joined to said section, - placing the connecting fitting (4) on the end section of the high-pressure hose (5), - performing a joining operation to form a sealed connection between the high-pressure hose (5) and the connection fitting (4), characterized in that Determining the quality of the connection between the connecting fitting (4) and the high-pressure hose (5), including - applying an electrical test signal to at least one connection (12; 16) of a test device (18) having two connections (12, 16), wherein a first connection (12) is electrically and / or magnetically coupled to the connection fitting (4) and a second connection (16) is electrically and / or magnetically coupled contactlessly to at least one of the reinforcement layers (6, 7) of the high-pressure hose (5), - detecting an electrical response signal generated in said testing device, - comparing the response signal with a setpoint value range stored in a memory of the test device (18) for the relevant high-pressure hose-connection fitting pair.

2. The method according to claim 1, characterized in that In order to electrically couple the first terminal (12) of the test device (18) to the connection fitting (4), a contact probe is placed on the connection fitting (4) to establish electrical contact between the contact probe and the connection fitting (4).

3. The method according to claim 1 or 2, characterized in that The second connection (16) of the test device (18) is electrically or magnetically coupled to the at least one reinforcement layer (6, 7) adjacent to the connection fitting (4), i.e., at a distance from the connection fitting of not more than three times the diameter of the high-pressure hose (5).

4. The method according to claim 3, characterized in that The second connection (16) of the test device (18) is electrically or magnetically coupled to the connection fitting (4) in close proximity and without contact to the at least one reinforcement layer (6, 7).

5. The method according to claim 1 or 2, characterized in that A second terminal (16) of the test device (18) is capacitively coupled to the at least one reinforcement layer (6, 7).

6. The method according to claim 1 or 2, characterized in that A second terminal (16) of the test device (18) is inductively coupled to the at least one reinforcement layer (6, 7).

7. The method according to claim 1 or 2, characterized in that in, Before the connection fitting (4) is placed on the end section of the high-pressure hose (5), the high-pressure hose (5) is stripped on the inside and / or outside of its end section in order to at least partially expose at least one metallic reinforcement layer (6, 7).

8. The method according to claim 1 or 2, characterized in that When using a connection fitting (4) with a screw connection (8) and a press sleeve (9), - placing the connecting fitting (4) on the high-pressure hose (5) in such a way that the screw connection (8) enters the high-pressure hose (5) from the inside and the high-pressure hose enters the annular gap between the screw connection (8) and the squeeze sleeve (9), - and when the tubular hydraulic pipeline thus formed is joined, the tubular hydraulic pipeline is placed in a radial press (1) having an extrusion tool with a plurality of extrusion bodies (P) by placing the extrusion sleeve (9) in the extrusion tool, and then the extrusion sleeve (9) is radially extruded by reducing the clear width of the annular gap of the connecting fitting (4).

9. The method according to claim 8, characterized in that The quality of the connection between the connecting fitting (4) and the high-pressure hose (5) is determined in the radial press (1).

10. The method according to claim 9, characterized in that The quality of the connection between the connecting fitting (4) and the high-pressure hose (5) is determined before the radial extrusion is completed.

11. The method according to claim 10, characterized in that: The testing device (18) communicates with a control device of the radial press (1) in such a way that the radial pressing of the pressing sleeve (9) is controlled as a function of a signal from the testing device (18).

12. The method according to claim 11, characterized in that: The end of the radial extrusion is controlled according to the signal of the testing device (18).

13. The method according to claim 8, characterized in that The hydraulic line is removed from the radial press (1) and placed in a pressure test bench, wherein the quality of the connection between the connecting fitting (4) and the high-pressure hose (5) is determined in the pressure test bench.

14. The method according to claim 13, characterized in that The quality of the connection between the connection fitting (4) and the high-pressure hose (5) is determined by applying different pressures using a test medium.

15. A radial press for carrying out the method according to claim 9, comprising a pressing tool with a plurality of pressing bodies (P) arranged around a pressing axis and movable radially relative to the pressing axis by means of a drive unit, and a testing device (18) with two connections (12, 16), wherein: The first of the joints (12, 16) is configured for electrical and / or magnetic coupling to the connection fitting (4), and the second joint (16) is configured for contactless electrical and / or magnetic coupling to at least one of the reinforcement layers (6, 7) of the tubular hydraulic pipeline.

16. The radial press according to claim 15, characterized in that The connections (12, 16) of the testing device (18) are arranged on one of the extrusion bodies (P) of the extrusion tool.

Images