Welding detection structure of strain gauge, wire welding device and multi-dimensional force sensor

Abstract

This application provides a welding inspection structure for a strain gauge, a wire welding device, and a multi-dimensional force sensor. The strain gauge includes a strain gauge body and wires extending from at least two electrical connection points on the strain gauge body. The connection ends of each wire are fixed to the corresponding electrical connection points by welding. The welding inspection structure includes a welding inspection unit, with both ends of the unit connected to the non-welded ends of two wires extending from any two electrical connection points, respectively, to detect the welding status of the connection ends of the wires to the corresponding electrical connection points. The welding inspection structure for the strain gauge provided in this application can connect with the non-welded ends of the wires to form a detection circuit, thereby allowing immediate detection of the welding quality and continuity between the wires and the electrical connection points after the welding process is completed. Furthermore, by relying on the electrical parameters of the inspection unit to determine the welding status, it avoids judgment errors caused by subjective human judgment, resulting in accurate and reliable inspection results.

Description

Technical Field

[0001] This utility model relates to the field of strain gauge manufacturing technology, and in particular to a welding inspection structure and wire welding device for strain gauges. Background Technology

[0002] A strain gauge is a mechanical sensing element that converts the deformation of an object into a change in electrical signal. Due to its high accuracy, fast response, and strong stability, it is widely used in stress and strain testing in aerospace, rail transportation, engineering machinery, and building structure inspection. The normal operation and signal transmission of a strain gauge depend on its reliable electrical connection with external wires. Currently, the industry commonly uses welding to fix the wires to the electrical connection points (pads or terminals) of the strain gauge, and the quality of the welding directly determines the sensing accuracy, operational stability, and service life of the strain gauge.

[0003] As strain gauges become increasingly smaller, the welding of the conductors to the electrical connection points during production can easily lead to problems such as incomplete soldering, false soldering, missed soldering, insufficient solder, solder joint cracking, and conductor detachment. These welding defects are difficult to visually identify immediately after welding, but they can cause abnormal contact resistance and poor conductivity stability at the connection points during subsequent use. During testing or use, external environmental factors such as vibration, temperature changes, and stress loads can cause strain gauges with welding defects to experience poor contact or open circuits, directly resulting in distorted strain signal acquisition and data jumps. This not only significantly reduces the accuracy of strain measurement but can also lead to the failure of the entire detection system, causing risks such as distorted engineering test data and misjudgments in equipment operation monitoring.

[0004] Currently, the inspection of strain gauge welding quality generally relies on manual visual inspection or electrical testing. Manual visual inspection can only identify visible defects such as solder joint misalignment, solder buildup, and obvious detachment, but it cannot accurately detect hidden welding problems such as cold solder joints, microcracks, and poor internal contact. Its accuracy is extremely low and subject to significant subjective error. Electrical testing must be performed after the strain gauge is fully assembled and the final product (e.g., a multi-dimensional force sensor), making it a post-inspection. If welding faults are detected, disassembly and re-welding are required, a cumbersome process with high rework costs, severely impacting production efficiency. Furthermore, most existing testing equipment is designed for overall strain gauge performance testing and cannot specifically inspect the welding status of wires and electrical connections. Consequently, it is impossible to quickly and accurately inspect welding quality after the welding process is completed, hindering timely screening and repair of welding defects.

[0005] In summary, the welding quality inspection of strain gauge wires in the existing technology suffers from problems such as poor targeting and low accuracy. Utility Model Content

[0006] The purpose of this invention is to solve the problems of poor targeting and low accuracy in the welding quality inspection of strain gauge wires in the prior art; and the problem that after manual wire welding, it is difficult to locate the non-welded end of the lead wire, thus making it impossible to use equipment to achieve automatic inspection.

[0007] To address the aforementioned problems, this utility model discloses a welding inspection structure for a strain gauge. The strain gauge includes a strain gauge body and wires extending from at least two electrical connection parts of the strain gauge body. The connection ends of each wire are fixed to the corresponding electrical connection parts by welding. Furthermore, the welding inspection structure includes a welding inspection unit, the two ends of which are respectively connected to the non-welded ends of two wires extending from any two electrical connection parts, and the welding status of the connection ends of the wires to the corresponding electrical connection parts is detected.

[0008] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment of the present invention has a welding detection unit as an electrical signal detection unit; wherein, the two ends of the electrical signal detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the two electrical connection parts and the electrical signal detection unit form an electrical signal circuit; and the electrical signal in the electrical signal circuit includes a current signal, a voltage signal or a resistance signal.

[0009] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment includes a first power supply component and a current acquisition device connected in series with each other; wherein, the two ends of the welding detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the first power supply component and the current acquisition device are connected in series with the strain gauge through the two electrical connection parts to form a current loop.

[0010] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment includes a welding detection unit comprising a second power supply component and a voltage acquisition device; wherein, the second power supply component is arranged in series between the non-welded ends of the wires welded to the corresponding electrical connection parts; the two ends of the voltage acquisition device are respectively connected to the non-welded ends of the two wires and form a parallel circuit with the second power supply component.

[0011] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment of the present invention has a welding detection unit as a resistance collector; the two ends of the resistance collector are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, forming a parallel circuit with the strain gauge.

[0012] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment of the present invention has a welding detection unit as a wireless signal detection unit; wherein, the two ends of the wireless signal detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the two electrical connection parts and the wireless signal detection unit form a wireless signal loop; and the wireless signal in the wireless signal loop includes a frequency signal or a pulse signal.

[0013] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment includes a signal transmitter connected to the non-welded end of one of two wires respectively welded to the corresponding electrical connection part, and a signal receiver connected to the non-welded end of the other wire.

[0014] According to another specific embodiment of the present invention, the welding detection structure of the strain gauge disclosed in this embodiment of the present invention has at least one electrical connection part from which multiple wires are led out, and any two wires led out from each electrical connection part are mutually conductive in the electrical connection part; furthermore, any two wires led out from different electrical connection parts are not directly conductive.

[0015] The present invention discloses a strain gauge wire welding device, including a strain gauge welding detection structure as described in any of the above embodiments, and a guide component. The wires are arranged in a predetermined direction on the guide component, and the connecting end of the wire is transported via the guide component to a position corresponding to the electrical connection part of the strain gauge. The non-welded end of the wire is connected to the welding detection structure.

[0016] According to another specific embodiment of the present invention, the strain gauge wire welding device disclosed in this embodiment of the present invention, after the connection end of the wire is welded to the corresponding electrical connection part and the guiding component is separated from the connection end of the wire, the welding detection structure detects the welding state of the connection end of the wire to the corresponding electrical connection part.

[0017] According to another specific embodiment of this utility model, the strain gauge wire welding device disclosed in this embodiment has an insulating region on the structural body and / or guiding component of the welding detection structure; the connection position between the non-welded end of the wire and the welding detection structure is located in the insulating region. It should be noted that if the guiding component itself is an insulator, then there is no need to separately provide an additional insulating region.

[0018] According to another specific embodiment of the present invention, the strain gauge wire welding device disclosed in this embodiment of the present invention has a detection connection part provided in the insulation area, and the non-welded end of the wire is connected to the welding detection structure via the detection connection part.

[0019] The present invention discloses a multidimensional force sensor, which is provided with multiple strain gauges. The welding quality of the wires of at least one strain gauge is detected by the welding detection structure of the strain gauges as described in any of the above embodiments.

[0020] The beneficial effects of this utility model are:

[0021] The welding inspection structure for strain gauges provided by this invention allows for direct electrical connection of the welding inspection structure to the non-welded ends of any two wires, thus constructing a complete closed-loop inspection circuit. By detecting the on / off state and resistance parameter changes of the inspection circuit, the welding status of the wire connection end and the corresponding electrical connection part can be determined as qualified. This enables precise detection of hidden defects that are invisible to the naked eye, improving inspection accuracy. Furthermore, the welding inspection unit only needs to connect to the non-welded ends of the wires to complete the inspection, without causing any damage to the weld joint, thus improving the yield rate. Simultaneously, inspection is performed immediately after the welding process, without waiting for the strain gauge to be fixed to the product to be attached, preventing unqualified products from entering subsequent assembly and testing processes, significantly reducing rework costs and material waste.

[0022] The strain gauge wire welding device provided by this utility model has a guiding component that can be used for the wire welding process itself. This allows for immediate welding quality inspection after the wire is welded to the strain gauge electrical connection, improving processing speed and product quality. It also avoids the problem of uncontrolled three-dimensional movement of the wire after the non-welded end is released, which would otherwise make it difficult to position the wire using equipment and hinder automatic detection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a strain gauge.

[0024] Figure 2 This is a schematic diagram of the welding inspection structure of the strain gauge provided in this embodiment of the utility model;

[0025] Figure 3 This is another structural schematic diagram of the welding inspection structure of the strain gauge provided in this embodiment of the utility model;

[0026] Figure 4 This is another structural schematic diagram of the welding inspection structure of the strain gauge provided in this embodiment of the utility model;

[0027] Figure 5 This is another structural schematic diagram of the welding inspection structure of the strain gauge provided in this embodiment of the utility model;

[0028] Figure 6 This is another structural schematic diagram of the welding inspection structure of the strain gauge provided in this embodiment of the utility model;

[0029] Figure 7 This is a schematic diagram of the strain gauge wire welding device provided in this embodiment of the utility model.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Strain gauge body; 2. Electrical connection; 3. Wire; 4. Guiding component; 5. Insulation area; 6. Detection connection. Detailed Implementation

[0032] refer to Figure 1 A strain gauge is a mechanical sensing element that can convert mechanical deformation into electrical signals. The strain gauge includes a strain gauge body 1 and wires 3 extending from at least two electrical connection parts 2 of the strain gauge body 1, wherein the connection ends of each wire 3 are fixed to the corresponding electrical connection part 2 by welding.

[0033] The strain gauge body 1 generally includes a substrate, a sensing grid area, and an electrical connection part 2 (which can be a solder pad or a connection point for electrical signal lines, etc.). The substrate is the load-bearing structure of the strain gauge, supporting the sensing grid area and the electrical connection part 2, and ensuring that the deformation of the measured object is accurately and uniformly transmitted to the sensing grid area. The sensing grid area senses mechanical deformation and converts it into an electrical signal. When the measured object undergoes tensile or compressive deformation, the sensing grid area deforms synchronously, causing a change in resistance and thus converting the mechanical deformation into an electrical signal. The electrical connection part 2 is the structure for signal transmission between the strain gauge and external components. By soldering wires 3 to the electrical connection part 2, the strain gauge can be connected to external electrical components, thereby outputting a signal.

[0034] The strain gauge includes at least two electrical connection parts 2. These at least two electrical connection parts 2 can be two, three, or even more.

[0035] Among them, the strain gauge with two electrical connection parts 2 is also a uniaxial strain gauge, which also has a sensing grid area. The two terminals are connected through the sensing grid area to measure strain in one direction.

[0036] A strain gauge with three electrical connections 2, also known as a half-bridge strain gauge, has two sensing grid regions (one a working grid and the other a compensation grid) and can automatically compensate for temperature drift. The three electrical connections 2 are respectively connected to the positive terminal of the working grid, the common terminal, and the negative terminal of the compensation grid. The terminal connected to the positive terminal of the working grid and the common terminal is conductive through the working grid, and the terminal connected to the negative terminal of the compensation grid and the common terminal is conductive through the compensation grid. The terminal connected to the positive terminal of the working grid and the negative terminal of the compensation grid is not directly conductive.

[0037] A strain gauge with four electrical connections 2 is also known as a full-bridge strain gauge. It has two sensing grid regions (composed of four grids) and can measure bidirectional strain, shear strain, and torque. The four grids inside are connected in series to form a ring, and the terminals are only connected to the grid endpoints.

[0038] A strain gauge with six electrical connections 2 is also known as a triaxial strain gauge. It has three sensing grid areas and can measure the stress and strain direction of a plane. Each pair of electrical connections 2 forms a group, and the electrical connections 2 of each group are connected only through the corresponding sensing grid area of ​​the group. The groups are insulated and do not conduct.

[0039] The strain gauge can be a metal diaphragm strain gauge or a capacitive strain gauge, and the electrical connection part 2 of the strain gauge can be a metal pad or a conductive contact.

[0040] One electrical connection 2 of a strain gauge can be connected to one or more wires 3. For example, for a strain gauge with two electrical connection 2, one wire 3 can be connected to the first electrical connection and two wires 3 (one for power supply and one for signal measurement) can be connected to the second electrical connection. For a strain gauge with three or four electrical connection 2, two wires 3 can be provided on each electrical connection 2 to form a bridge circuit.

[0041] One end of each wire 3 is a connecting end, and the other end is a non-welded end. The connecting end of the wire 3 refers to the end of the wire 3 near the electrical connection part 2, which is the fixed end for welding. It is fixed to the electrical connection part 2 of the strain gauge body 1 by welding process, so as to realize the electrical conduction and mechanical fixation between the wire 3 and the strain gauge body 1.

[0042] Correspondingly, the conductor 3 also has a non-welded end. The non-welded end of the conductor 3 refers to the suspended end of the conductor 3 away from the strain gauge body 1. The non-welded end is unwelded and unfixed, and is an exposed end that can be connected to external equipment. It is used to connect the welding detection unit, thereby establishing a detection circuit and completing the welding status detection.

[0043] Strain gauges are typically installed on the load-bearing surfaces of equipment, such as bridge steel beams, building beams and columns, the load-bearing or load-bearing structures of engineering machinery booms, or on the elastic strain surfaces of pressure sensors, torque sensors, and force sensors.

[0044] As described in the background art, the gradual reduction in the size of the strain gauge leads to a further reduction in the size of the electrical connection part 2. This makes it extremely easy for problems such as incomplete soldering, false soldering, missed soldering, insufficient solder, solder joint cracking, and wire connection end detachment to occur when the wire 3 is soldered to the electrical connection part 2. To solve the above technical problems, this embodiment provides a welding detection structure for the strain gauge, which is used to connect with the non-welded end of the wire 3 to form a detection circuit, thereby detecting the welding quality and welding continuity between the wire 3 and the electrical connection part 2.

[0045] Next, the welding inspection structure of the strain gauge will be described in detail with reference to the attached drawings.

[0046] Example 1:

[0047] This embodiment provides a welding inspection structure for strain gauges. (Reference) Figure 2 The welding inspection structure includes a welding inspection unit. The two ends of the welding inspection unit are respectively connected to the non-welded ends of two wires 3 led out from any two electrical connection parts 2, and the connection end of the wire 3 is used to inspect the welding status of the corresponding electrical connection part 2.

[0048] Specifically, the welding inspection unit is an independent, external inspection device. It can form a detection circuit by connecting with the non-welded end of the conductor 3, thereby detecting the welding quality and continuity status between the conductor 3 and the electrical connection 2. The welding inspection unit can be a continuity detection module, such as a buzzer continuity tester, which identifies welding defects such as incomplete soldering, detachment, and open circuits by detecting whether the circuit is conductive. Alternatively, the welding inspection unit can be a resistance detection module, such as a digital multimeter, which identifies welding defects such as cold solder joints, false solder joints, poor solder contact, and insufficient solder by detecting the resistance value of the welding circuit.

[0049] The connection end of the wire 3 is welded and fixed to the corresponding electrical connection part 2 of the strain gauge body 1 by soldering, laser welding or other welding methods, so as to realize the electrical conduction between the wire 3 and the internal circuit of the strain gauge body 1.

[0050] During welding inspection, the two detection terminals of the welding inspection unit are electrically connected to the non-welded ends of any two wires 3 respectively. Without contacting the strain gauge body 1 and the weld point, a complete closed-loop inspection circuit can be constructed. By observing the on / off state of the inspection circuit and the change in resistance parameters, it can be determined whether the welding status between the connection end of the wire 3 and the corresponding electrical connection part 2 is qualified.

[0051] When installing the welding inspection unit, the two inspection terminals of the unit can be electrically connected to the non-welded ends of two wires 3 leading from any two electrical connection parts 2 to form a complete closed-loop inspection circuit. The welding status of the connection end of the wire 3 and the corresponding electrical connection part 2 is determined by the on / off state and electrical parameters of the inspection circuit. For example, if there are two electrical connection parts 2, with two wires 3 welded to the first electrical connection part and one wire 3 welded to the second electrical connection part, then the two wires 3 on the first electrical connection part need to be connected to the wire 3 on the second electrical connection part to determine whether the welding status is normal.

[0052] After the welding inspection unit is installed, the inspection program is started. The inspection unit will automatically apply a detection signal to the circuit under test and collect and analyze the changes in the electrical signal in real time. Taking the resistance detection module as an example, it will start measuring the resistance value in the circuit and continuously monitor the stability of the resistance value.

[0053] The welding detection unit will compare and analyze the collected electrical signal data with the preset standard data. If the detected electrical parameters exceed the preset reasonable range or the signal shows abnormal fluctuations, it is determined that there are welding defects. At the same time, the detection unit can output the detection results in ways such as digital display, indicator light prompt, and sound alarm, facilitating the operator to know the welding quality situation in a timely manner. Taking the resistance detection module as an example, if the resistance value is within the standard conduction resistance range of the strain gauge, it is determined that the welding is qualified; if the resistance value is infinite, it is determined that there is a missed weld or a loose weld; if the resistance value is偏大 and unstable, it is determined that there is a false weld or insufficient solder.

[0054] For the strain gauges determined to have welding defects, corresponding treatments can be carried out according to the defect types, such as re-welding, repair welding, etc. After the treatment is completed, welding detection can be carried out again until the detection is qualified.

[0055] With such a structure, by directly electrically connecting the welding detection structure to the non-welded ends of any two wires 3, a complete closed-loop detection circuit can be constructed. By detecting the on-off state and resistance parameter changes of the detection circuit, it can be determined whether the welding state of the connection end of the wire 3 and the corresponding electrical connection part 2 is qualified, and it can accurately detect hidden defects that cannot be identified by the human eye, improving the detection accuracy. Moreover, the welding detection unit can complete the detection only by connecting to the non-welded ends of the wire 3, without causing any damage to the solder joints, improving the yield rate. At the same time, the detection is carried out immediately after the welding process is completed, without waiting for the strain gauge to be fixed on the product to be pasted, avoiding unqualified products from flowing into the subsequent assembly and testing processes, and greatly reducing the rework cost and material loss.

[0056] Furthermore, in the welding detection structure of the strain gauge, the welding detection unit is an electrical signal detection unit; among them, the two ends of the electrical signal detection unit are respectively connected to the non-welded ends of the wires 3 welded to the corresponding electrical connection parts 2, and the two electrical connection parts 2 and the electrical signal detection unit form an electrical signal loop. And the electrical signals in the electrical signal loop include current signals, voltage signals or resistance signals.

[0057] Specifically, the electrical signal detection unit is a device that can generate, collect and analyze electrical signals. It judges the welding state of the wire 3 and the electrical connection part 2 by detecting the changes in current, voltage or resistance in the electrical signal loop and comparing them with the preset electrical signal threshold.

[0058] The electrical signal loop refers to a closed circuit jointly composed of the electrical signal detection unit, the wire 3, the electrical connection part 2 and the induction grid area inside the strain gauge. Electrical signals can be transmitted in this loop, and the abnormal changes in the electrical signals in the loop can reflect the welding state and quality problems.

[0059] The current signal is a parameter related to the current in the circuit (such as current magnitude, stability, and rate of change) used to determine the welding status. For example, during normal welding, the current remains constant; if there are defects such as poor welding, the current will show a significant drop or fluctuation.

[0060] A voltage signal is the voltage signal detected after a constant current is applied to a circuit. When there are defects in the weld, the voltage drop will deviate from the normal range.

[0061] Resistance signal refers to the resistance value in a circuit that is directly measured. Under normal welding conditions, the resistance value is within a stable range; if welding defects exist, the resistance value will increase significantly.

[0062] During welding inspection, the two ends of the electrical signal detection unit are first connected to the non-welded ends of the wires 3 welded to the corresponding electrical connection parts 2. Signal detection is then performed by activating the electrical signal detection unit. For example, the welding detection unit may apply a constant voltage to the circuit to collect current data; or flow a constant current through the circuit to collect voltage drop data; or directly measure the circuit resistance value. The signal analysis module of the electrical signal detection unit compares the collected data with preset standard thresholds. If the data exceeds the standard threshold or exhibits abnormal fluctuations, it is determined to be a welding defect, and the detection results are output through a display screen, indicator lights, etc.

[0063] Furthermore, in one implementation of the electrical signal detection unit, refer to Figure 3 The welding detection unit includes a first power supply component and a current acquisition device connected in series with each other; wherein, the two ends of the welding detection unit are respectively connected to the non-welded ends of the wires 3 welded to the corresponding electrical connection parts 2, and the first power supply component and the current acquisition device are connected in series with the strain gauge through the two electrical connection parts 2 to form a current loop.

[0064] The first power supply component refers to a device that provides stable electrical energy to the current loop. It typically uses a DC power supply and can output a constant voltage or current to ensure the stability of the current in the loop. Examples include a 3.7V lithium battery or a 5V regulated power supply.

[0065] A current acquisition device is a device used to collect current signals in a current loop. For example, it could be the current setting on a multimeter.

[0066] The first power supply component, the current acquisition device, and the strain gauge are connected in series to form a current loop. For example, the positive terminal of the first power supply component can be connected to one end of the current acquisition device, the other end of the current acquisition device can be connected to the non-welded end of the first wire 3, and the non-welded end of the second wire 3 can be connected to the negative terminal of the DC regulated power supply to form a closed loop.

[0067] During welding inspection, the first power supply component supplies power, and the current collector reads the current value. According to Ohm's law, it can be calculated that: the theoretical current of the current loop = power supply voltage ÷ (nominal resistance of the strain gauge + self-resistance of the two wires 3). Compare the actual current value read by the current collector with the calculated theoretical current value. If the error between the actual current and the theoretical current is within ±5%, it indicates that the welding is qualified. If the actual current is much smaller than the theoretical current, it means that there is a contact resistance at one of the solder joints, resulting in an increase in the total resistance of the loop and a decrease in the current. At this time, it can be determined as single-sided false welding. If the current is 0, it means that the loop is completely disconnected and at least one wire 3 has failed in welding. If the actual current is much larger than the theoretical current, it may be that there is a short circuit fault inside the strain gauge.

[0068] Furthermore, in another implementation manner of the electrical signal detection unit, refer to Figure 4 , the welding detection unit includes a second power supply component and a voltage collector; wherein, the second power supply component is arranged in series between the non-welded ends of the wire 3 welded to the corresponding electrical connection part 2; both ends of the voltage collector are respectively connected to the non-welded ends of the two wires 3, forming a parallel circuit with the second power supply component.

[0069] The second power supply component is a device that provides electrical energy for the detection loop and is arranged in series between the non-welded ends of the wire 3. The second power supply component can be, for example, a DC constant current source (such as outputting 1 mA, 10 mA), or a fixed resistor is connected in series with a DC power supply to simulate a constant current output.

[0070] The voltage collector is a device used to collect the voltage signal between the non-welded ends of the wire 3. The voltage collector can be, for example, the voltage range of a multimeter.

[0071] When forming a parallel loop, connect one end of the second power supply component to the non-welded end of the first wire 3, the other end to the non-welded end of the second wire 3, and at the same time connect the positive pole of the voltage collector to the non-welded end of the first wire 3 and the negative pole to the non-welded end of the second wire 3.

[0072] During welding inspection, the welding state can be determined based on the voltage signal. Specifically, the second power supply component supplies power, and the voltage collector reads the stabilized DC voltage value. According to Ohm's law, it can be calculated that: the theoretical voltage in the circuit = constant current value × (strain gauge nominal resistance + the resistance of two wires 3 themselves). Compare the actual voltage read by the voltage collector with the theoretical voltage. If the error between the actual voltage and the theoretical voltage is within ±3%, it indicates that the welding is qualified. If the actual voltage is greater than the theoretical voltage, it means that the total resistance of the circuit has increased, and there is poor contact at the solder joint, resulting in an increase in voltage. At this time, it can be determined that wire 3 is poorly soldered. If the actual voltage is 0 or close to the power supply voltage, it means that the circuit is disconnected and the welding has failed. At this time, it can be determined that wire 3 is de-soldered. If the actual voltage is much less than the theoretical voltage, it may be that there is a short circuit fault inside the strain gauge.

[0073] During welding inspection, the welding state can also be determined based on the current signal. Specifically, calculate the theoretical impedance in the circuit according to Ohm's law for calculating impedance. If the error between the actual impedance and the theoretical impedance is within ±5%, and the impedance value is stable, it indicates that the solder joint has good contact and there is no additional contact impedance, and the welding quality meets the standard. If the actual impedance exceeds the theoretical impedance by more than 10%, or the impedance value fluctuates significantly, it indicates that there is poor contact at the solder joint. At this time, it is determined that wire 3 is poorly soldered. If the actual impedance is infinite or much greater than the theoretical impedance (such as more than 10 times), it means that wire 3 is completely disconnected from the strain gauge and the welding has completely failed. At this time, it can be determined that wire 3 is de-soldered.

[0074] Furthermore, in another implementation of the electrical signal detection unit, refer to Figure 5 , the welding detection unit is a resistance collector; both ends of the resistance collector are respectively connected to the non-welded ends of the wire 3 welded to the corresponding electrical connection part 2 and form a parallel circuit with the strain gauge.

[0075] Specifically, the resistance collector is a device used to measure the resistance value in the circuit. For example, it can be the ohm range of a multimeter.

[0076] When forming a parallel circuit, one end of the resistance collector is connected to the non-welded end of the first wire 3, and the other end is connected to the non-welded end of the second wire 3 to form a parallel circuit.

[0077] During welding inspection, the resistance acquisition unit reads the resistance value in the circuit and compares it with the pre-calibrated resistance value of the strain gauge (the strain gauge's nominal resistance). The resistance value measured at the end of lead 3 equals the strain gauge's nominal resistance plus the resistance of both leads 3 themselves. An error within ±0.5Ω indicates a successful weld. If the measured value is much greater than the strain gauge's nominal resistance (e.g., more than 5Ω greater than the reference value), but not infinite, it indicates poor contact at one of the weld points, resulting in excessive conductive resistance. In this case, lead 3 can be identified as having a poor weld. If the measured value shows infinite (OL), it indicates that one of the leads 3 is completely disconnected from the strain gauge, and the weld has failed. In this case, lead 3 can be identified as having detached from the weld.

[0078] Furthermore, in the welding inspection structure of this strain gauge, the welding inspection unit is a wireless signal inspection unit; wherein, the two ends of the wireless signal inspection unit are respectively connected to the non-welded ends of the wires 3 welded to the corresponding electrical connection parts 2, and the two electrical connection parts 2 and the wireless signal inspection unit form a wireless signal loop. Moreover, the wireless signal in the wireless signal loop includes frequency signals or pulse signals.

[0079] Specifically, the wireless signal detection unit refers to a device that detects the welding status of the wire 3 and the electrical connection 2 by transmitting and receiving wireless signals. The wireless signal detection unit can achieve signal transmission and analysis without physical contact, making it more suitable for detection scenarios in complex environments or where wiring is difficult.

[0080] The wireless signal loop refers to the signal transmission path formed by the wireless signal detection unit, the wire 3, the electrical connection part 2, and the strain gauge body 1, in which the wireless signal can be transmitted. Abnormal changes in the signal can reflect welding quality problems.

[0081] Frequency signal refers to the method of judging the welding status by detecting changes in the frequency of wireless signals. During normal welding of conductor 3, the signal attenuation in the wireless signal loop is stable, and the frequency remains essentially constant. If there is a welding defect in conductor 3, the wireless signal loop will experience a signal frequency shift due to impedance changes. For example, a fixed-frequency wireless signal is transmitted to the strain gauge loop, and the frequency of the received signal is monitored. If the frequency deviation exceeds a preset threshold, the welding is deemed unqualified.

[0082] Pulse signals are used to assess welding quality by utilizing the transmission time and reflection characteristics of pulse signals. When defects exist in the weld, the signal will be abnormally reflected at the defect location, causing changes in the transmission time or waveform of the pulse signal. For example, a pulse signal is emitted into the strain gauge circuit, and the round-trip time of the signal is measured. If the time exceeds the normal range, the weld is deemed unqualified.

[0083] Furthermore, in one feasible implementation of the wireless signal detection unit, reference is made to... Figure 6The welding inspection unit includes a signal transmitter connected to the non-welded end of one of the two wires 3 that are respectively welded to the corresponding electrical connection part 2, and a signal receiver connected to the non-welded end of the other.

[0084] Specifically, a signal transmitter is a device capable of transmitting wireless signals into the wireless loop containing the strain gauge. It typically consists of a signal generation module, a power amplification module, and an antenna, and is able to generate stable frequency or pulse signals. Specifically, it can be a frequency signal transmitter capable of generating a fixed-frequency sine wave signal, which adjusts the signal frequency and power to adapt to the welding inspection of different types of strain gauges. Alternatively, it can be a pulse signal transmitter generating a pulse with a specific pulse width and period, which controls the pulse parameters to adapt to the welding inspection of different types of strain gauges.

[0085] A signal receiver is a device capable of receiving wireless signals after they have passed through the wireless loop containing the strain gauge. It typically consists of a receiving antenna, a signal conditioning module, and a data acquisition module, and is able to accurately capture and analyze the characteristics of the feedback signal. It can be a frequency signal receiver for receiving and analyzing frequency signals, or a pulse signal receiver for receiving and analyzing pulse signals.

[0086] When setting up a wireless signal loop, the signal transmitter is connected to the non-soldered end of the wire 3 soldered to one of the electrical connection parts 2, and the signal receiver is connected to the non-soldered end of the wire 3 soldered to the other electrical connection part 2.

[0087] During welding inspection, the signal transmitter is activated to transmit a wireless signal according to the set signal type and parameters; simultaneously, the signal receiver is activated to receive feedback signals in real time. The signal receiver transmits the received signal to the signal analysis module for comparison and analysis with the transmitted signal. If the difference in signal characteristics exceeds a preset range, a welding defect is determined to exist. For example, when the frequency signal receiver detects that the frequency deviation between the received signal and the transmitted signal exceeds ±2%, a welding defect is determined to exist.

[0088] Furthermore, in the welding inspection structure of this strain gauge, at least one electrical connection part 2 leads out multiple wires 3, and any two wires 3 leading out from each electrical connection part 2 are interconnected within the electrical connection part 2. Moreover, any two wires 3 leading out from different electrical connection parts 2 are not directly interconnected.

[0089] Specifically, any two wires 3 drawn from different electrical connection parts 2 are not directly connected, which can ensure electrical isolation between each electrical connection part 2 and avoid signal interference or short circuit problems.

[0090] Furthermore, in the welding inspection structure of the strain gauge, the welding inspection structure also includes a structural body, and the welding inspection unit is disposed on the structural body. The welding inspection unit is connected to the non-welded end of the corresponding wire 3 at an insulated area of ​​the structural body.

[0091] Specifically, the structural body refers to the carrier used to install and fix the welding inspection unit. The insulating area refers to the area on the structural body used to connect the welding inspection unit to the non-welded end of the conductor 3. The insulating area has good insulation performance, which can avoid short circuit problems between different conductors 3 or between conductor 3 and the structural body, thereby improving the safety and reliability of the inspection system.

[0092] Example 2:

[0093] Based on the strain gauge welding inspection structure described in Embodiment 1, this embodiment provides a strain gauge wire welding device.

[0094] refer to Figure 7 The wire welding apparatus includes a welding detection structure for a strain gauge as described in Embodiment 1 and a guide member 4. The wires are arranged in a predetermined direction on the guide member 4, and the connecting ends of the wires are transported via the guide member 4 to positions corresponding to the electrical connection portions of the strain gauge. The non-welded ends of the wires are connected to the welding detection structure.

[0095] Specifically, the guide component 4 is a guide member used to constrain the attitude of the wires on the strain gauge and transport the wires to the target position (e.g., the position where they contact the electrical connection part of the strain gauge). The guide component 4 can be a slot-type guide component, with multiple parallel limiting slots on its surface. The width of the slots is adapted to the diameter of the strain gauge wires, allowing the wires to be inserted into the slots for limiting. One end of the slot corresponds to the electrical connection part (pad) of the strain gauge, precisely transporting the connection end of the wire to the position of the pad. The guide component 4 can also be configured as a vacuum adsorption type guide component, with an overall plate-like structure. The surface of the plate has micro-adsorption holes, and a negative pressure adsorption force is generated by an external negative pressure fan, thereby flatly adsorbing the wires onto the plate, achieving directional alignment of the wires. The guide component 4 can also fix the wires to the plate in other possible ways (e.g., snap-fit). The guide component 4 can also be directly used in the wire welding process. Solder is applied to the guide component 4 at the position corresponding to the connection end of the wire. When the wire is guided to the target position, the wire is directly welded to the electrical connection by heating the position corresponding to the connection end of the wire on the guide component 4. This allows for immediate welding quality inspection after the welding of the wire to the strain gauge's electrical connection, improving processing speed and product quality. It also avoids the problem of uncontrolled three-dimensional movement of the wire after the non-welded end is released, which would otherwise make it difficult to position the wire using equipment and hinder automatic detection.

[0096] The predetermined arrangement direction of the conductors refers to the direction of extension of the conductors that is predetermined based on the shape of the strain gauge, the location of the electrical connection, welding process requirements, etc.

[0097] During operation, the strain gauge's wires (single or multiple) are first fixed to the guide component 4. Then, the guide component 4 is used to precisely guide the connection ends of each wire to the corresponding welding positions on the electrical connection parts (pads / terminals) of the strain gauge body. Next, the non-welded ends of the wires are connected to the detection ports of the welding detection structure. The connection step between the wires and the welding detection structure can be performed before or after welding. However, it should be noted that to avoid residual metal material on the guide component 4 affecting the welding detection results, the guide component 4 must be separated from the connection ends of the wires before performing the welding detection.

[0098] This structure enables precise delivery of the wires via the guiding component 4, resolving issues such as wire welding misalignment and inaccurate positioning caused by the small size of the micro-strain gauge. This reduces the incidence of defects like incomplete welds, missed welds, and weld cracks from the source. Furthermore, integrating the welding fixture with the inspection structure eliminates the need for subsequent secondary workpiece clamping, simplifying the production process.

[0099] More preferably, in this wire welding device, after the connection end of the wire is welded to the corresponding electrical connection part and the guide component 4 is separated from the connection end of the wire, the welding detection structure detects the welding status of the connection end of the wire to the corresponding electrical connection part.

[0100] Specifically, before inspecting the welding status, only the guide component 4 can be separated from the connection end of the wire, while the rest of the wire remains in the guide component 4; alternatively, the guide component 4 can be completely detached from the wire. Separation methods can include mechanical lifting or negative pressure suction.

[0101] Furthermore, in one implementation, an insulating region 5 is provided on the structural body of the welding detection structure; the connection position between the non-welded end of the conductor and the welding detection structure is located in the insulating region 5.

[0102] Specifically, insulation region 5 is a structural area with electrical isolation function, which can be an insulating coating or an insulating gasket. By setting insulation region 5, conductive interference from the metal structure of the tooling equipment can be isolated, preventing leakage, cross-current, and short circuit faults in the detection circuit, thereby improving the accuracy of the detection.

[0103] In other possible implementations, the guide component 4 is provided with an insulating region 5; the connection point between the non-welded end of the wire and the welding detection structure is located in the insulating region 5. It should be noted that if the guide component 4 itself is an insulator, then there is no need to provide an additional insulating region.

[0104] In other possible implementations, an insulating region 5 can be provided on both the structural body and the guiding component 4 of the welding detection structure; the connection position between the non-welded end of the wire and the welding detection structure is located in the insulating region 5.

[0105] Furthermore, in this wire welding device, the insulation area 5 is provided with a detection connection part 6, and the non-welded end of the wire is connected to the welding detection structure via the detection connection part 6.

[0106] Specifically, the detection connection part 6 is a connecting component integrated within the insulation region 5 for connecting the non-welded end of the wire to the welded detection structure. It can be a conductive copper sheet or a conductive probe disposed within the insulation region 5. The non-welded end of the wire does not need to be directly connected to the detection unit; instead, it connects to the detection unit via the detection connection part 6 as an intermediate connector, improving the efficiency and convenience of wiring.

[0107] This wire welding device achieves precise wire transport through the guiding component 4, and, in conjunction with the welding inspection structure, enables simultaneous quality inspection after the welding process. This allows for immediate wire quality inspection after welding, improving strain gauge production efficiency. The guiding component 4 itself can be used for the wire welding process, allowing for immediate welding quality inspection after the wire is welded to the strain gauge's electrical connection, thus improving processing speed and product quality. This also avoids the problem of uncontrolled three-dimensional movement of the wire after the non-welded end is released, which would otherwise make equipment positioning difficult and hinder automatic inspection.

[0108] Example 3:

[0109] Based on the strain gauge welding inspection structure described in Embodiment 1, this embodiment provides a multi-dimensional force sensor. This multi-dimensional force sensor is equipped with multiple strain gauges, wherein the welding quality of the wires of at least one strain gauge is detected using the strain gauge welding inspection structure as described in Embodiment 1.

[0110] A multidimensional force sensor is a sensor capable of simultaneously measuring forces in two or more dimensions. A multidimensional force sensor typically consists of an elastic body, multiple strain gauges, etc.

[0111] The welding quality of the wires of at least one strain gauge on the multidimensional force sensor is detected using the welding inspection structure of the strain gauge as described in Example 1.

[0112] The specific testing methods can be as follows: after the multi-dimensional force sensor is assembled, a welding inspection structure can be used to inspect the welding quality of the strain gauge wires one by one. Alternatively, the welding inspection structure can be integrated into the multi-dimensional force sensor production line, and the inspection can be performed immediately after the strain gauge welding process is completed.

[0113] The multi-dimensional force sensor provided in this embodiment features a weld inspection structure that detects and addresses welding defects in the strain gauge's wires. This prevents signal distortion, open circuits, and other malfunctions caused by welding issues during sensor use, resulting in higher reliability and stability. Furthermore, welding defects can be detected during the sensor's production process, avoiding the need for disassembly and reassembly due to subsequent performance testing failures. This reduces rework and production time costs, improving production efficiency. In addition, this weld inspection structure is applicable to the testing needs of different types of multi-dimensional force sensors, enhancing the comprehensiveness and accuracy of the inspection.

[0114] Although the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the present invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the present invention to these descriptions. Those skilled in the art can make various changes in form and detail, including some simple deductions or substitutions, without departing from the spirit and scope of the present invention.

Claims

1. A welding inspection structure for strain gauges, characterized in that, The strain gauge includes a strain gauge body and wires extending from at least two electrical connection portions of the strain gauge body, wherein the connection ends of each wire are fixed to the corresponding electrical connection portion by welding; and the welding detection structure includes a welding detection unit, the two ends of which are respectively connected to the non-welded ends of two wires extending from any two electrical connection portions to detect the welding status of the connection ends of the wires to the corresponding electrical connection portions.

2. The welding inspection structure for strain gauges as described in claim 1, characterized in that, The welding detection unit is an electrical signal detection unit; wherein, the two ends of the electrical signal detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the two electrical connection parts and the electrical signal detection unit form an electrical signal loop; and the electrical signal in the electrical signal loop includes a current signal, a voltage signal or a resistance signal.

3. The welding inspection structure for strain gauges as described in claim 2, characterized in that, The welding detection unit includes a first power supply component and a current acquisition device connected in series; wherein, both ends of the welding detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the first power supply component, the current acquisition device and the strain gauge are connected in series via the two electrical connection parts to form a current loop.

4. The welding inspection structure for strain gauges as described in claim 2, characterized in that, The welding detection unit includes a second power supply component and a voltage acquisition device; wherein, the second power supply component is arranged in series between the non-welded ends of the wires welded to the corresponding electrical connection parts; The two ends of the voltage acquisition device are respectively connected to the non-welded ends of the two wires, forming a parallel circuit with the second power supply component.

5. The welding inspection structure for strain gauges as described in claim 2, characterized in that, The welding detection unit is a resistance acquisition device; The two ends of the resistance acquisition device are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, forming a parallel circuit with the strain gauge.

6. The welding inspection structure for strain gauges as described in claim 1, characterized in that, The welding detection unit is a wireless signal detection unit; wherein, the two ends of the wireless signal detection unit are respectively connected to the non-welded ends of the wires welded to the corresponding electrical connection parts, and the two electrical connection parts and the wireless signal detection unit form a wireless signal loop; and the wireless signal in the wireless signal loop includes frequency signals or pulse signals.

7. The welding inspection structure for strain gauges as described in claim 6, characterized in that, The welding detection unit includes a signal transmitter connected to the non-welded end of one of two wires respectively welded to the corresponding electrical connection, and a signal receiver connected to the non-welded end of the other.

8. The welding inspection structure for strain gauges as described in claim 1, characterized in that, At least one of the electrical connection portions leads out multiple wires, and any two wires leading out from each of the electrical connection portions are interconnected in the electrical connection portion; furthermore, any two wires leading out from different electrical connection portions are not directly interconnected.

9. A wire welding device for a strain gauge, characterized in that, include: The welding inspection structure for a strain gauge as described in any one of claims 1-8, and the guide member, wherein the wires are arranged in a predetermined direction on the guide member, the connecting end of the wires is transported via the guide member to a position corresponding to the electrical connection portion of the strain gauge, and the non-welded end of the wires is connected to the welding inspection structure.

10. The wire welding apparatus for a strain gauge as described in claim 9, characterized in that, After the connection end of the wire is welded to the corresponding electrical connection part and the guide component is separated from the connection end of the wire, the welding detection structure detects the welding status of the connection end of the wire and the corresponding electrical connection part.

11. The wire welding apparatus for a strain gauge as described in claim 9, characterized in that, An insulating area is provided on the structural body of the welding detection structure and / or the guiding component; The connection point between the non-welded end of the conductor and the welding detection structure is located in the insulation area.

12. The strain gauge wire welding apparatus as described in claim 11, characterized in that, The insulation area is provided with a detection connection part, and the non-welded end of the conductor is connected to the welded detection structure via the detection connection part.

13. A multidimensional force sensor, characterized in that, The multidimensional force sensor is equipped with multiple strain gauges, wherein the welding quality of the wires of at least one strain gauge is detected by the welding detection structure of the strain gauges as described in any one of claims 1-8.

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