Device, cable harness test station and procedure for leak testing

Abstract

Device for leak testing of a cable gland comprising: a test container with a leak-proof fitting disposed in an opening of the test container to accommodate a cable gland, a clamping device for hermetically fixing the cable gland to the fitting, and a fluid supply device connected to the test container and serving to generate an overpressure in the test container.

Description

Device, cable harness test station and procedure for leak testing Technical field The present invention relates to a device for testing the tightness of a cable harness nozzle, a cable harness test station including the device, and a corresponding procedure for testing the tightness of a cable harness nozzle with the device. State of the art In the prior art, vacuum bucket stations are known for testing the leak tightness of cable bundle nozzles. A vacuum bucket station consists of a vacuum barrel with an opening, over which the nozzle to be tested is placed. After the pressure in the vacuum barrel is reduced, the extent to which the negative pressure is maintained is checked. If the pressure in the vacuum barrel increases, it can be assumed that the cable bundle nozzle is leak tight. The vacuum bucket station has a corresponding receptacle for each type of nozzle. Consequently, a separate vacuum barrel must be provided for each type of nozzle, which entails considerable effort during the testing process, as well as high supply costs.Furthermore, wire harness testing stations known in the prior art typically have a compressed air supply, which in vacuum barrel stations is also used to generate the vacuum with the aid of Venturi nozzles. As a result, vacuum generation in vacuum barrel stations requires a significant amount of energy. All of the aforementioned disadvantages of the prior art considerably reduce the efficiency of the leak test in terms of energy and, in particular, are time-consuming. Document CN 114858370 A refers to a leak-tightness testing machine for rubber cable harness sheaths and a test method for the same. US patent 6382016 B1 refers to a water tightness test device to check whether a watertight seal has been achieved in the space between bundled electrical cables that have been inserted into a pass-through nozzle. US patent 6564617 B1 refers to a device for testing the watertightness of a rubber sleeve. Description of the invention Therefore, a technical objective of the invention is to provide, using the simplest structural means possible, a device and a corresponding procedure for performing a particularly energy-efficient leak test of cable harness ferrules. This objective is achieved by the objects of the independent claims. The advantageous improvements of the invention are indicated in the dependent claims, the description, and the accompanying figures. According to a first aspect of the invention, the objective is achieved by means of a device according to the invention for the leak-tightness test of a cable bundle nozzle, comprising a test container with a fluid-tight upper part arranged in an opening of the test container to accommodate a cable bundle nozzle, a clamping device for securing the fluid-tight upper part to the lid, and a fluid supply device, which is connected to the test container and serves to generate an overpressure in the test container. Using overpressure instead of a vacuum to test the leak tightness of a cable harness nozzle allows for a significantly more energy-efficient leak test. Overpressure is often generated centrally and can be supplied to the device according to the invention in an energy-efficient manner. Vacuum generation, on the other hand, requires the use of separate Venturi nozzles or compressors. In both cases, vacuum generation is less efficient than overpressure generation using a central generating unit. Furthermore, the device of the invention has a particularly simple and compact structure, allowing for easy integration into a cable harness testing station.Furthermore, the device is compatible with a wide variety of different nozzles, as the fluid-tight placement of the upper part in the fitting can be ensured by means of the tightening device. The fluid delivery device can be an overpressure delivery device. The fluid used for the leak test can be air, so the overpressure delivery device is a compressed air device. However, it is also possible to use another fluid, such as water and / or another gas. The nozzle can be a butyl nozzle. Alternatively or additionally, the nozzle can be made primarily of flexible plastic or rubber. The top piece may also be made of rubber and / or a flexible plastic. The lid may also include a sealing element and a support structure, such that the support structure rests on the test container. The cap and / or the cap sealing element may have a shape that suits a specific nozzle design. The test vessel may have internal slopes. These slopes may be designed to prevent the wire bundle connectors from tilting inside the test vessel when the wire bundle is removed. The test vessel may have an outlet valve to compensate for pressure after the leak test. The device has a pressure sensor to measure the pressure in the test container. The use of a pressure sensor allows for particularly precise monitoring of pressure changes within the test vessel, thus enabling the accurate detection of leaks in the nozzle under test. The pressure sensor can be located within the test vessel itself. Alternatively, or additionally, it can be located in the fluid supply device. According to one embodiment, the fluid supply device may include a flow sensor to measure the fluid flow from the supply device to the test vessel. A flow sensor allows for particularly precise testing of the nozzle's leak tightness. By maintaining a constant overpressure in the test vessel, the nozzle's leak tightness can be determined based on the fluid flow required to maintain the overpressure from the supply device. The flow sensor can be used to determine this required fluid flow. Alternatively, the leak tightness of the nozzle under test can be determined solely based on the fluid flow from the supply device to the test vessel, as the pressure curve in the test vessel directly affects the incoming fluid flow.Thus, from the fluid flow from the fluid supply device, the pressure curve in the test vessel can be deduced, and therefore the leak tightness of the nozzle. The fluid supply device has two pressure regulators, and each of the pressure regulators includes one of the pressure sensors. The use of two pressure regulators allows for a particularly efficient and precise determination of the leak tightness of the nozzle under test. A pressure sensor integrated into the pressure regulator detects the pressure curve in the test vessel, and from this curve, conclusions can be drawn about the leak tightness of the nozzle being tested. In particular, the use of two pressure regulators enables a particularly effective leak tightness test of a nozzle. This is achieved by using a first pressure regulator, which allows a relatively large fluid flow from the fluid supply device, to rapidly increase the overpressure in the test vessel.When a first pressure level is reached, it is then possible, by means of a second, more precise control pressure regulator, which allows a relatively low flow of fluid from the fluid supply device, to precisely increase the overpressure inside the test vessel to a test pressure. A pressure regulator according to the present invention is a pressure-controlled valve. This means that the pressure regulator can be set to a desired pressure level, such that flow through the regulator is prevented when the desired pressure level is reached on the fluid outlet side of the regulator. Flow through the regulator is enabled when the overpressure on the fluid outlet side of the regulator falls below the desired pressure level. According to one embodiment, the clamping device may have two clamping elements, which are arranged in such a way that the clamping elements support each other in a closed position and connect the upper part to the fitting in a fluid-tight manner. The arrangement of two clamping elements allows for particularly efficient leak testing, as these two elements enable a particularly rapid, fluid-tight connection of the upper part to be tested in the nozzle, thus making the leak test especially quick and easy. Furthermore, using clamping elements to establish a fluid-tight connection between the adapter and the upper part to be tested allows for testing upper parts of different configurations without requiring a specific adapter for each one. Consequently, a particularly flexible and cost-effective leak test is possible. According to one embodiment, the fastening elements can be designed so that they lock together in the closed position and remain locked when a force is applied from the direction of the test vessel. By locking the fastening elements, they can be prevented from opening unintentionally and uncontrollably from the closed position when the overpressure in the test vessel is increased. Uncontrolled opening of the fastening elements can cause injury to the person operating the device. Furthermore, opening interrupts the leak test. Consequently, a particularly safe and effective leak test is possible with the device according to the invention. Therefore, the fastening elements may have a kind of self-locking mechanism, which keeps the fastening elements in the closed position. According to one embodiment, the clamping device may have at least one, preferably two, locking devices, which are arranged and configured such that the locking devices hold the clamping elements in the closed position. The closing of the clamping elements in the closed position by means of one, preferably two, locking devices enables a secure and fluid-tight connection between the upper part to be tested and the upper part of the test vessel, thus facilitating a particularly efficient leak test. The locking device may have at least one presence pin, which is designed and arranged so that the presence pin is activated in the closed position by the clamping device and causes the locking device to close. It is also possible that activation of the presence pin initiates the leak test of the test vessel. According to one embodiment, the test container can be moved relative to the clamping device in such a way that the distance between the clamping device and the upper part is variable. By moving the test vessel relative to the clamping device, specific adaptation of the upper part to upper parts of varying heights is unnecessary. Instead, the height of the gap between the clamping device and the upper part can be varied. Consequently, a particularly flexible and energy-efficient leak test can be performed. The distance between the clamping device and the fitting can be adjusted using an adjusting screw, which allows the height of the test flange to be adjusted within the device. According to a second aspect of the invention, the objective is achieved by means of a wire harness test station for the functional testing of a wire harness that has a device according to the invention. Integrating the device of the invention into a cable harness test station enables a particularly efficient leak test of a nozzle, as the person performing the leak test can carry out the functional test of the cable harness as well as the leak test of the cable harness nozzles, in parallel and / or sequentially, without having to transport them between different test stations. Furthermore, the device according to the invention can be connected, for example, to the overpressure supply already present in the cable harness test station. According to a third aspect of the invention, the objective is achieved by a procedure for testing the leak tightness of a cable bundle nozzle with a device according to the invention comprising the following steps: The upper part is placed on a lid of a test vessel, ensuring a fluid-tight connection between the upper part and the fixing piece. The test vessel is then filled with a fluid using a fluid supply device until a test pressure is reached. The overpressure in the test vessel is measured during a test period, and the nozzle's leak tightness is determined based on the overpressure variation during that period. In particular, the leak tightness of the nozzle under test can be determined with exceptional efficiency and precision by evaluating the pressure curve during the test period. Furthermore, as previously mentioned, compressed air is used as the fluid in accordance with the present invention.Compressed air is usually available when testing cable bundles and is generated centrally, so that the leak test is particularly energy efficient during the test time using the procedure according to the invention. It is also possible to record the results of the leak test. Consequently, a pressure curve can be assigned and recorded for each sleeve to be tested, which can also be tracked later, particularly useful for subsequent quality management. The test pressure can be between 150 mbar and 250 mbar, preferably 200 mbar. The time for a leak test from the filling of the test container can be between 100 and 200 seconds, preferably 160 seconds. The filling of the test container can be initiated by activating the presence pin. According to one embodiment, to determine the nozzle's leak tightness, a fluid flow can be determined through the fluid supply device, necessary to maintain a constant test pressure in the test vessel for a test time. Determining the fluid flow rate from the fluid supply device for the nozzle leak test allows for a particularly precise and efficient determination of the leak tightness of the nozzle under test. The leak tightness of the nozzle can be determined based on the fluid flow rate and / or the pressure change in the test vessel during the test period. For example, the nozzle is considered leak-tight if the flow rate exceeds 50 ml / min and the overpressure in the test vessel deviates by a maximum of 20 mbar from the test pressure. To reach the test pressure, the test vessel is filled by means of a first pressure regulator to a first overpressure and by means of a second pressure regulator to the test pressure, wherein the second pressure regulator has a lower overpressure than the first pressure regulator and wherein each of the pressure regulators includes a pressure sensor. The use of two pressure regulators allows the test vessel to be filled with the fluid particularly quickly until the test pressure is reached. Consequently, the procedure for checking the leak tightness of a cable harness nozzle is particularly efficient. The first overpressure can be between 130 mbar and 230 mbar, preferably 180 mbar. The overpressure of the first pressure regulator can be, for example, between 300 mbar and 700 mbar, preferably 500 mbar. The overpressure of the second pressure regulator can be identical to the test pressure. Brief description of the figures An example of an advantageous embodiment of the invention is explained below with reference to the accompanying figures. They show: Figure 1 an isometric view of device 1 according to the invention in accordance with an exemplary embodiment; Figure 2 a side view of device 1 according to the invention in accordance with figure 1; Figure 3 a side view of device 1 according to the invention as shown in Figures 1 and 2; Figures 1 to 3 show a device 1 according to the invention, which has a test container 2 with an opening 3 and a top piece 4 (not shown in Figure 1 or Figure 3). A nozzle of the wiring harness to be tested can be placed on this top piece 4. The cap 4 is shown in Figure 2. The cap 4 may be shaped to fit the test container 2 and, preferably, designed so that the cap 4 can be placed on the test container 2 and is positioned above the opening 3 of the test container 2. The cap 4 may have a sealing element, preferably elastic, that allows a fluid-tight connection between the test container 2 and the nozzle to be tested. A nozzle to be tested is not shown in the figures. Furthermore, device 1 has a clamping device 5, which allows the upper part to be secured to the lid 4. For this purpose, the clamping device 5 may have a first clamping element 10 and a second clamping element 11, which, in a closed position, as shown in the figures, press an upper part (not shown) against the fitting 4 and thereby connect the upper part to the fitting 4 in a fluid-tight manner. The two clamping elements 10 and 11 may be arranged and designed such that they engage with each other in the closed position and remain in the closed position when a force is applied from the direction of the test vessel 2. As can be seen in particular in Figures 1 and 3, the clamping elements 10 and 11 may be fork-shaped for this purpose.Furthermore, the first clamping element 10 can be arranged in a closed position below the second clamping element 11. The engagement of the two clamping elements 10, 11 can be made possible by providing one or two contact surfaces on the underside of the second clamping element 11. In the closed position, the second clamping element 11 can rest on the first clamping element 10; moreover, the contact surface of the second clamping element 11, which extends transversely to the support surface, can touch the first clamping element 10. The clamping device 5 can also have two locking devices 12, 13, which are designed and arranged such that the locking devices 12, 13 retain the clamping elements 10, 11 in the closed position.Thus, as shown in the figures, the first and second locking devices 12, 13 can be essentially cylindrical or rectangular, with a clamping structure, preferably a retaining element, formed at their upper ends. The clamping structure can be designed such that, when the locking elements 10, 11 are moved from an open to a closed position, the retaining structures of the locking devices 12, 13 automatically engage and thereby hold the locking elements 10, 11 in the closed position. In particular, the locking devices 12, 13 hold the second locking element 11 in the closed position, while the second locking element 11 holds the first locking element 10 in the closed position. Device 1 also includes a fluid supply device 6, which is connected to test vessel 2 and serves to generate overpressure in test vessel 2. For clarity, the fluid hoses are not shown; only the individual components of the fluid supply device 6 are depicted. The fluid supply device 6 may include a flow sensor 7 that measures the fluid flow rate in test vessel 2. As can be seen in particular in Figure 2, the flow sensor 7 can be mounted on a clamping device 14. The clamping device 5 can also be mounted on the clamping device 14. Furthermore, the fluid supply device 6 includes a first pressure regulator 8 and a second pressure regulator 9, each of which is fluidly connected to test vessel 2.These pressure regulators 8 and 9 may be equipped with pressure sensors to determine the overpressure at the outlet of the respective pressure regulator 8 and 9 and / or the prevailing overpressure in the test vessel 2. The overpressure of the first pressure regulator 8 may be lower than the overpressure of the second pressure regulator 9. The overpressure of the first pressure regulator 8 may correspond to the test pressure. Automated fluid supply to the test vessels 2 is also possible, for example, by means of an automated valve. As shown in particular in Figure 2, the pressure regulator(s) 8 and 9 may also be mounted on the clamping device 14. The pressure regulators 8 and 9 may be fluidly connected, on one side via the flow sensor 7, to the fluid supply (not shown), and / or, on the other side, fluidly connected to the test vessel 2. The test vessel 2 can also be mounted on the clamping device 14. For this purpose, a frame 15 can accommodate the test vessel 2 and connect it to the clamping device 14. Furthermore, the test vessel 2 can be designed so that it can be moved relative to the clamping device 5. Specifically, the frame 15 can be provided with an adjusting screw 16, which is designed and arranged so that the test vessel 2, resting on the adjusting screw 16, can be moved relative to the clamping device 14 and the clamping device 5 mounted on the clamping device 14. The figures are merely schematic representations and serve only to explain the invention. Identical elements or elements of equivalent effect are systematically designated with the same reference numbers. List of references 1 Device 2 Test container 3 Opening 4 Top piece 5 Tightening device 6 Fluid supply device 7 Flow sensor 8 First pressure regulator 9 Second pressure regulator 10 First tightening element 11 Second tightening element 12 First locking device 13 Second locking device 14 Clamping device 15 Frame 16 Adjustment screw

Claims

1. A device (1) for testing the leak tightness of a cable harness sleeve, comprising: - a test vessel (2) with a fluid-tight upper portion (4) arranged over an opening (3) of the test vessel (2) to accommodate a cable harness sleeve, - a clamping device (5) for securing the sleeve to the fluid-tight upper portion (4), and - a fluid supply device (6) connected to the test vessel (2) for generating overpressure in the test vessel (2), - with a pressure sensor for measuring the overpressure in the test vessel (2), - characterized in that the fluid supply device (6) comprises a first pressure regulator (8) and a second pressure regulator (9), wherein the pressure regulators (8, 9) respectively comprise a pressure sensor,- wherein the second pressure regulator (9) has a lower overpressure than the first pressure regulator (8), - wherein the device is configured to reach the test pressure, fill the test vessel (2) to a first overpressure by means of the first pressure regulator (8), and fill it to the test pressure by means of the second pressure regulator (9).

2. Device (1) according to claim 1, wherein the fluid supply device (6) has a flow sensor (7) for measuring the fluid flow from the fluid supply device (6) to the test vessel (2).

3. Device (1) according to any one of the preceding claims, wherein the tightening device (5) has two tightening elements (10, 11), which are arranged such that the tightening elements (10,11) overlap in a closed position and connect the sleeve to the upper part (4) in a fluid-tight manner.

4. Device (1) according to claim 3, wherein the clamping elements (10, 11) are configured such that the clamping elements (10, 11) engage with each other in the closed position and remain in the closed position when a force is applied from the direction of the test vessel (2).

5. Device (1) according to claim 3 or 4, wherein the clamping device (5) has at least one, preferably two, locking devices (12, 13), which are arranged and configured such that the locking devices (12, 13) retain the clamping elements (10, 11) in the closed position.

6. Device (1) according to any one of the preceding claims,wherein the test vessel (2) can be moved relative to the clamping device (5) such that the distance between the clamping device (5) and the upper part (4) varies.

7. Cable harness test station for functional testing of a cable harness, comprising a device (1) according to any of the preceding claims.

8. Method for leak-testing a cable harness sleeve with a device (1) according to any one of claims 1 to 6, comprising the following steps: - positioning the sleeve on the upper part (4) of the test vessel (2), such that the sleeve is fluid-tightly connected to the upper part (4), - filling the test vessel (2) with a fluid by means of the fluid supply device (6) until a test pressure is reached in the test vessel (2),- Determining the overpressure in the test vessel (2) during a test time and determining the sleeve's leak tightness based on the variation of the overpressure during the test time, wherein, to reach the test pressure, the test vessel (2) is filled by means of the first pressure regulator (8) to a first overpressure and by means of the second pressure regulator (9) to the test pressure, wherein the second pressure regulator (9) has a lower overpressure than the first pressure regulator (8), and wherein the pressure regulators (8, 9) each comprise a pressure sensor.

9. A method according to claim 8, wherein, to determine the sleeve's leak tightness, a fluid flow is determined through the fluid supply device (6), necessary to maintain a constant test pressure in the test vessel (2) during a test time.

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