EP0878878A2 - Sensor device for force measurement - Google Patents

Abstract

The reception adapter has a multiple of force sensors (14, 16), housed in a lower part (12) connected with the force receiver e.g. a crimping punch, acted on with a force in a loaded condition. For the prodn. of an electrical evaluatable signal as a reaction to the loading. An upper part (10) is provided at a distance to the lower part (12) in the loading direction, and works in conjunction with the force transmitter eg. the crimping press. The force sensors are so arranged and designed, that they are loaded bending moment free in the loading condition and besides the multiple of force sensors (14, 16), otherwise no frictional connection results between the lower part (12) and the upper part (10).

Description

The invention relates to a mechanical receiving adapter according to the preamble of claim 1; especially with installation of two (force) sensors for the purpose of Measurement signal acquisition for comprehensive quality assurance, hereinafter abbreviated "QS", preferably in the Crimping technique.

The following are the areas of application of QS for crimping: The crimping process itself and its implementation, the tool that shapes and shapes the crimp, the press that operates the tool and the machine, which defines the line to be processed for the Crimping process leads and sorted sorted.

Generic adapter adapters are used in crimping technology for example by cable assemblers for measuring of force profiles, which depend on the angle, used by the way, or by time.

Such a mounting adapter records the force curve, the during the crimping or crimping process of a cable end sleeve applied with an electrical conductor is, and passes a corresponding measurement signal to a electronic evaluation device.

It is generally the purpose of the crimp connection, one gastight, electrically conductive and mechanically stable Secure connection between two electrical conductors.

Crimp connections can be in particular: stranded wire with end sleeve, stranded wire with wire, wire with wire or assembly, stranded wire with stranded wire and other aspects of cable assembly. Usually, electrical lines are crimped in the area of signal and control lines with wire cross-sections from 0.07mm ² to battery cables from 35mm ² ; Commonly processed wire cross sections are in the range of 0.15mm ² to 2.5mm ² .

Is present in the cable assembly industry the crimp control in the car cable assembly on widely used and prescribed because of the quality of these connections directly related to protection of human life, e.g. at the safe Contact for actuating airbag, ABS and Brake assistant, for power steering as well as for that extensive tax management in one vehicle.

• der Aufnahmeadapter, in welchem ein Sensor zum Erzeugen des Meßsignals montiert ist,
• ein nachgeschaltetes Messgerät, das die Meßsignalanalyse ausführt,
• sowie ein PC-Auswerteprogramm, etwa unter Windows laufend, das für die Statistische Prozesskontrolle ("SPC") sowie das Qualitätsmanagement verfügbar ist.

The following measuring chain is currently available for quality management in crimp technology:

• the adapter, in which a sensor for generating the measurement signal is mounted,
• a downstream measuring device that carries out the measurement signal analysis,
• as well as a PC evaluation program, running under Windows, for example, which is available for statistical process control ("SPC") and quality management.

The data transfer is either wireless or galvanic coupled with a measuring cable. The distance between the MR and the measuring device is usually - dependent from the means of production - a few meters.

The measurement method for crimp control is usually based on a comparative measurement. The measuring device is the Ideal manufacturing process of the crimping process based on the Measured value history learned or stored (teachin Fashion). 5 to 50, preferably 10, are typical Individual force curves of acceptable, i.e. compliant Crimp connections. From these ten digitized Force curves that a capable manufacturing process should reflect a mean force curve calculated, the so-called reference curve. This The reference curve is saved in the measuring device.

In monitoring mode, this is now with each crimp Reference curve with the current, measured force measured value curve compared. Is the current one Force course within predetermined limits, then the current crimp connection is recognized as accepted and led into the well storage.

But if errors occur - these can have various causes own - then the crimp connection is considered not acceptable and must be sorted out.

• Isolierung im Drahtcrimpkontakt,
• fehlende Einzellitzen aus einer Schaar von Litzen,
• fehlerhafte Drahtcrimphöhe,
• falscher Drahtquerschnitt,
• fehlende oder fehlerhafte Isoliertülle im Isocrimp,
• unkorrekte Drahtzuführung zum Crimpkontakt,
• Einzellitzen außerhalb des Drahtcrimpes, aber im Crimpstempelbereich.

This can be caused by e.g. B. be

• Insulation in wire crimp contact,
• missing single strands from a pair of strands,
• faulty wire crimp height,
• wrong wire cross section,
• missing or faulty insulating sleeve in the isocrimp,
• incorrect wire feed to the crimp contact,
• Individual strands outside the wire crimp, but in the crimp stamp area.

All of these potential errors require detection extraordinary sensitivity and sensitivity of the Measuring system. The use of a piezoelectric sensor (with quartz crystal) is a typical application. The previously offered and applied on the market However, recording adapters cannot make sensitive diagnoses. The mechanical structure is designed with conventional recording adapters that a large part of the power flow lines flow through the force sensor, but not all. The result is that smaller, if significant, Force components can not be detected. For The previous solution was sufficient for initial QA tasks already out, but the ones to be processed, getting smaller increasing wire cross sections also have proportionately fewer Signal portion of the total crimp contact that is used for the Fault detection is available and needed.

The timely detection of the smallest deviations in the recorded force profile (i.e. the measured force curve over time) is of the crimping technique of great importance.

This is made more difficult by most previous adapters add that the assembly of the force sensors either in the lower part of the press in a mass-intensive mechanical recording takes place, or in Force reflux in the press stand. This is enough for coarse detections due to disadvantageous Force shunts and the resulting splitting of force flow lines in these applications however, the sensor does not have enough information for precise evaluation.

There are already applications of force sensors in the upper press area known, but only ever executed that only part of the lines of force flow through deformation forces flowing through the crimp contact the sensor is guided. The mechanical construction constructed bypass flow conducts proportional flow lines past the sensor used for detection of errors is applied. With all previous solutions the useful to interference signal distance is therefore not sufficient.

The object of the present invention is therefore a Generic adapters to create, in which all lines of force flow recorded piezoelectrically and in Be evaluated in real time. Further it is intended the adapter easily and easily Almost all presses available on the market can be assembled to design so that this for a wide range of applications can be used for wire cross sections and how to handle a force sensor itself, so calibrated to measure the absolute force can.

With the absolute value measurement of the crimping force should be simultaneous tool and press monitoring guaranteed and the prerequisite for comprehensive statements on Process capability created around the crimping process will.

The task is performed by the adapter according to the claim 1 solved. Advantageous developments of the invention are described in the subclaims.

• weitergehende Fehlervermeidung,
• hohe Sicherheit für alle Crimpungen,
• keine fehlerhaften Crimpungen, die zur Auslieferung gelangen,
• Vermeidung kostenaufwendiger Rückrufaktionen,
• ausgezeichneter Werkzeugschutz,
• Fertigungprozess läuft unter statistischer Kontrolle.

The following QA results can advantageously be achieved with the adapter according to the invention:

• further avoidance of errors,
• high security for all crimping,
• no faulty crimping that is delivered,
• Avoid costly product recalls,
• excellent tool protection,
• Manufacturing process runs under statistical control.

Fig. 1:

eine Frontansicht des mechanischen Aufnahmeadapters gemäß einer ersten, bevorzugten Ausführungsform der Erfindung;

Fig. 2:

eine Seitenansicht des Aufnahmeadapters gemäß Fig. 1;

Fig. 3:

eine Schnittansicht durch die Seitenansicht der Fig. 2;

Fig. 4:

eine Draufsicht auf den ausführungsgemäßen Aufnahmeadapter; und

Fig. 5:

eine Draufsicht auf das Unterteil des Aufnahmeadapters bei abgenommenem Oberteil (in Perspektive gemäß Fig. 4).

Further advantages, features and details of the invention emerge from the following exemplary embodiments with reference to the figures; of which show:

Fig. 1:

a front view of the mechanical receiving adapter according to a first preferred embodiment of the invention;

Fig. 2:

a side view of the receiving adapter of FIG. 1;

Fig. 3:

a sectional view through the side view of Fig. 2;

Fig. 4:

a plan view of the embodiment adapter; and

Fig. 5:

a plan view of the lower part of the receiving adapter with the upper part removed (in perspective according to FIG. 4).

The mechanical structure is shown in drawing 1. The basic idea of this invention is all during the crimping process occurring crimping forces leading to deformation of the crimp contact to fully grasp.

This is achieved in that a mechanical separation point is built into the power flow, on the one hand the power flow is clearly and correctly channeled and completely leads to the force sensors and on the other hand no adverse influence of any kind creates the crimping force generated by the press; see. the illustration in FIG. 1 - front view, Fig. 2 - side view and Fig.3 - sectional view.

The area in which the adapter is put together is used (installed) with the two force sensors, lies in the so-called ramming area of the press. It is the area where the press generated Force is introduced into the tool. The one used there mechanical coupling element of the press is replaced by looking the same and working the same Coupling link with implemented force sensors as a recording adapter (measurement RAM) in the sense of the present invention.

1 to 3 is made of hardened Steel and vice versa U-shaped. It consists of an upper part 10 and a lower part 12 of two Force sensors 14, 16 which are mounted in the lower part, and a common signal feed 18 to one of externally accessible connector 20, also in the lower part assembled.

The power flow generated by a press gets into the Upper part 10, which by means of openings 22 of the To connect upper part 10 screws with the press is. Due to the mechanical separation the power flow exclusively through the two Force sensors in the lower part. From there it flows Force continues via two ramming punches 24, 26 of the lower part 12 into an existing stamping or crimping tool.

The upper part 10 is a flat, plane-parallel plate realized. The lower part 12 is a flat, plane-parallel Printing part with two right-angled, equal long legs that form the ramming punches 24, 26, in which the two force sensors are embedded are.

Depending on the crimping tool used, on the the adapter presses in press mode, the Power transmission to the crimping tool symmetrically or asymmetrical.

In any case, the two ram stamps are of equal length with a length of about 13mm and are about 30mm apart away; the total height of the flat pressure part is about 17mm, the total height of the adapter is approx. 29.0mm.

About the force flowing through both ram punches to record correctly and reproducibly Force sensors as pairs with the same transmission characteristics mechanically mounted in parallel.

The mechanical coupling point from top to bottom only form the surfaces of the two force sensors. Top and top are held together and mechanically clamped Lower part by two special expansion screws 28, 30 of size M4, which is centrally controlled by the force sensors guided and held in the lower part 12. This is physically assured that the lines of force flow within of the adapter only flow through the two sensors; see. Fig. 3.

The receiving adapter is particularly preferably designed in this way and dimensioned that the already existing Mounting bores and mounting threads on commercially available Presses for the assembly of the invention Adapters are used. This allows particularly simple the conversion of existing presses.

The adapter is mounted on the press with two mounting screws completely free of tension over the Upper part and the bores 22, contactless from below passed through openings 32 of the lower part 12. This Screws do not have anything when installed in the press Reaction on the force coupling between top and Lower part, regardless of the assembly torque applied.

The force is not always transferred to the crimping tool by the crimping tool itself due to the design symmetrically secured, there are different designs of crimping tools on the market.

By the line of force sewage system implemented in the invention is assured that all available and generated Crimping forces used to deform the crimp generated only and exclusively by the Force sensors flow.

Through the electrical connection of both sensors 14, 16 for a measurement signal is obtained from the sum of the two Individual signals the total signal that the power flow represented in the adapter. Whether a symmetrical or asymmetrical power transmission takes place, the result is always the recording of the total force. The invention ensures optimal measurement signal acquisition, which in turn sensitive measuring signal analysis for error detection allowed during the crimping process.

The geometric dimensions of the quartz force sensors 14, 16 are a height of 5.2mm, a diameter of 14.5mm, the cable connection is a DV connector. The Sensors have an inner hole for M4 or M6 special expansion screws. The sensors become electrical installed as a couple with the same sensitivity.

The sensors are implemented underground, the common measurement signal is due to an externally accessible SMC type connectors or on an externally mounted one Transmission source for a data transfer; see. about 3 and 5.

The constructive design between the upper and lower part takes place so that 0.07 to 0.1mm distance between these lie around the necessary for power sewerage mechanical gap before deposition of waste and wear parts, originating from crimp technology, too protect. Cause all kinds of contamination Force shunt what to avoid.

The sensors themselves and the electrical wiring are embedded in silicone rubber. This will Faults caused by the influence of oil and moisture as well as pollution. The narrow one Gap also adequately secures the capacitive shielding. In the case of a cable outlet, there is a holder 34 provided with kink protection to stabilize the measuring cable.

This adapter is designed so that symmetrical Power transmission and corresponding force sensor Forces up to 40kN (40,000N) can be measured. The Resolution is typically 1 / 10,000th. Measuring range and resolution depend on the applied sensors.

Typical crimping forces for a wire cross section of 0.15mm ^{2 are} approximately 2.5 to 3.5kN, the typical crimping forces for 1.0mm ² are approximately 7.0 to 9.0kN.

Claims (5)

Recording adapter for power transmission between a force transducer, such as a crimping press, and a force transducer for pressing, squeezing or loading processes, such as a crimping die, characterized by
a plurality of force sensors (14, 16) which are subjected to a force in a load state and are received in a lower part (12) connected to the force transducer for generating an electrically evaluable signal in response to the load
and an upper part provided in the loading direction at a distance from the lower part (12), resting on the plurality of force sensors (14, 16) and intended to cooperate with the force transmitter,
wherein the force sensors are arranged and designed such that they are loaded without bending moment in the load state and in addition to the majority of the force sensors (14, 16) there is no other force connection between the lower part (12) and the upper part (10). Recording adapter according to claim 1, characterized in that the force sensors as quartz crystal sensors are realized and with an electronic Acquisition and evaluation unit for recording a plurality of sequentially consecutive ones Signal states of the quartz crystal sensors during a loading process, especially one Crimping process are formed. Recording adapter according to claim 1 or 2, characterized in that a connection between the Power sensor and the upper part by means of a screw connection done by an opening (22) Can be produced in the plate-shaped upper part (10) is, through the lower part (12) access to this screw connection enables is. Recording adapter according to one of claims 1 to 3, characterized in that a mechanical connection between the upper part (10) and the lower part (12) by means of one of the plurality of force sensors corresponding plurality of clamping screws can be produced by openings in the upper part (10) in the screws assigned receptacles in the respective force sensors can be performed. Recording adapter according to one of claims 1 to 4, characterized in that the upper part and / or the lower part are designed so that they on connection elements commercially available crimping presses can be connected are.

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