CN101793579A - Calibration device of miniature pressure sensor - Google Patents

Abstract

The invention discloses a calibration device for a miniature pressure sensor, which comprises a calibration device base, a bearing seat, a loading plate, a guiding and fixing shaft, an adjustment seat and a pressure head of a sensor. The guiding and fixing shaft is arranged on the bearing seat, and the The adjustment seat is set on the guide fixed shaft and can move up and down along the fixed shaft, the loading plate is arranged on the upper end of the bearing seat, and the bearing seat and the sensor pressure head are arranged on the lower end of the bearing seat. The adjustment seats are connected by four deflection-correcting spring steel sheets. Through the above-mentioned structure, the present invention enables the calibration device to have self-balancing capability, and the device has strong anti-eccentric load capability, and provides a miniature pressure sensor calibration device with high precision, simple installation, convenient operation and general versatility.

Description

Calibration device for miniature pressure sensor

1. Technical field

The invention relates to the field of pressure sensor testing, in particular to a static calibration device for small and miniature pressure sensors.

2. Background technology

Miniature pressure sensors are used for force measurement on small contact surfaces. It has the advantages of small measuring range, high force measurement accuracy and reliable performance. Its pressure sensitive element and signal conditioning circuit are integrated and packaged in a plastic package. The contact force is conducted through the top stainless steel contact to become a pressure sensitive element. The resistance value changes proportionally with the applied force. The level changes accordingly.

To use the pressure sensor to measure the contact force, the pressure sensor must first be calibrated to determine the relationship between the sensor output value and the input. In scientific measurement, sensor calibration is an indispensable and important step. The measurement accuracy of the sensor is one of the most important performance indicators for evaluating the sensor, and its errors include random errors and systematic errors. For the miniature pressure sensor, its random error is mainly caused by internal signal processing circuit, quantization error, external interference and other factors; the system error is mainly determined by the calibration accuracy of the calibration system. Due to the small size of the micro sensor itself and the small contact surface of the spherical contact, it is easily disturbed by the environment during calibration and force measurement. To measure accurately, it is first necessary to ensure that the force can be stably applied to the sensor during calibration, and minimize the effect of the external interference force of the environment on the sensor. Therefore, the design of the sensor calibration device and the research of the calibration method are very important, and its calibration accuracy will directly affect the measurement accuracy when it is used.

Weight calibration is to use grade weights to provide standard loading force, directly use grade weights as a reference, the force value accuracy is high, and it is commonly used in the calibration of medium and small range force sensors.

3. Contents of the invention

The purpose of the present invention is to provide a calibration method and device with simple use, convenient operation and high calibration accuracy, which is suitable for calibration and testing of small-scale pressure sensors, especially for micro sensors with point contact force.

Technical scheme of the present invention is:

A calibration device for a miniature pressure sensor, comprising a calibration device base, a bearing seat, a loading plate, a guiding and fixing shaft, an adjusting seat and a pressure head of a sensor, the described guiding and fixing shaft is arranged on the bearing seat, and the described adjusting seat is arranged On the guide fixed shaft and can move up and down along the fixed shaft, the loading disc is set on the upper end of the bearing seat, and the sensor pressure head, the bearing seat and the adjustment are set on the lower end of the bearing seat. The three seats are connected by four deflection-correcting spring steel sheets.

The adjustment seat is also provided with an adjustment threaded hole and a locking threaded hole to fix the bolt handle, and a screw is arranged in the groove, and the upper end of the screw is a screw knob; the threaded locking hole and the The above-mentioned guiding and fixing shaft hole is connected, and a fixing bolt handle is arranged in the above-mentioned locking threaded hole.

The pressure head of the sensor is an adjustable pressure head of the sensor, and the adjustable pressure head is threadedly connected with the bearing seat.

Compared with the existing pressure sensor calibration device, the present invention has beneficial effects as follows:

1. Strong anti-eccentric load capability and high precision.

The inclination of the tray is an important factor affecting the linearity of the calibration device, and the present invention can always keep the tray perpendicular to the force-bearing direction during use. When the weight is loaded, the weight is not at the center point of the weight plate, a rotational torque will be generated relatively. But this torque will be offset by the four parallel rectifying spring steel sheets, so as to ensure that the weight plate is always horizontal, so that the resultant force loaded on the miniature pressure sensor is always vertical, so no matter where the weight is placed on the weight plate, It has no effect on the sensor.

2. It can calibrate the miniature pressure sensor with small force contact point.

Due to the fine structure of the miniature pressure sensor, the range of force measurement is not large, the contact method of the stainless steel metal ball used to accept the external pressure, and the metal ball is small in size, so it is not possible to directly load the weight on the sensor. The present invention utilizes the adjustable sensor pressure head to directly contact the pressure sensor contacts, so that the force of the weight can act stably on the pressure sensor, and the adjustable sensor pressure head can be replaced to meet the needs of sensor calibration with different sizes and contact surface shapes.

3. Self-balancing capacity.

When the present invention is in use, the output signal of the sensor should be observed first and the height position of the bearing seat should be adjusted at the same time. When the height is adjusted until the sensor has a non-zero signal, the adjustable sensor pressure head is just in contact with the metal contact of the sensor. When the weight is loaded on the weight plate, because the adjustable sensor pressure head is in contact with the stressed metal contact of the sensor, the support force of the correction spring is still equal to the sum of the gravity of the weight plate, the bearing seat and the adjustable sensor pressure head , the pressure on the sensor is the weight of the added weight. The greater the weight of the weight plate, the greater the deformation of the four springs, but by adjusting the height, the initial force on the sensor can always be guaranteed to be zero, thus realizing self-balancing adjustment.

4. Consistent linearity.

When the weight is loaded on the weight plate, since the adjustable sensor pressure head and the metal contact of the sensor are in contact with each other, when the weight of the loaded weight increases or decreases, the deformation of the correction spring steel sheet will not change again, that is The pressure carried by the sensor is still the weight of the weight.

4. Description of drawings

Figure 1 is a front view of the present invention.

Figure 2 is a side view of the present invention.

Figure 3 is a top view of the present invention.

5. Specific implementation

Fig. 1 is a schematic diagram of the three-dimensional structure of the present invention. Among them: 1 is the micro sensor calibration platform base; 2 is the guide fixed shaft; 3 is the adjustment seat; 4 is the fixed bolt handle; 5 is the height adjustment screw; 6 is the screw bearing seat; 7 is the screw knob; 8 is the correction spring steel 9 is a weight plate; 10 is a bearing seat; 11 is an adjustable sensor pressure head; 12 is a sensor fixture; 13 is a base adjustment nut.

The micro sensor is fixed on the calibration table base 1 through the sensor fixture 12, and the adjustable sensor pressure head 11 installed through the bearing seat 10 on the left side of the calibration table base contacts the stainless steel ball on the top of the micro sensor; the adjustable sensor pressure head 11 can be replaced Contact pressure heads of different sizes and different contact shapes are used for different pressure sensors. A weight plate 9 is installed above the bearing seat 10 for loading weights of different masses.

The height adjustment screw 5 on the right side is vertically fixed on the calibration table base 1 through the screw bearing seat 6, and the adjustment seat 3 and the height adjustment screw 5 are connected by threads, and the screw knob 7 on the top of the height adjustment screw 5 can be rotated to adjust the adjustment seat 3, the adjustment seat 3 can be locked on the guide fixed shaft 2 through the fixing bolt handle 4.

The middle of the bearing seat 10 and the adjustment seat 3 is connected by four deviation-correcting spring steel sheets 8, and the deviation-correcting spring steel sheets have been quenched to have the same length and the same hardness. When there is no load on the weight plate, the sum of the gravity of the weight plate 9, the bearing seat 10 and the adjustable sensor pressure head 11 is just equal to the upward elastic support force of the deviation-correcting spring steel sheet 8, realizing self-balancing adjustment. The height of the bearing seat 10 is adjusted by adjusting the screw knob 7, so that the adjustable sensor pressure head 11 is just in contact with the metal contact of the sensor. When the weight is loaded on the weight plate 9, because the adjustable sensor pressure head 11 is in contact with the stressed metal contact point of the sensor, there is no displacement, and the four deflection-correcting spring steel sheets 8 do not produce relative deformation. It is still equal to the sum of the gravity of the weight plate 9, the bearing seat 10 and the adjustable sensor pressure head 11, and the pressure on the sensor is the weight of the added weight.

When the weight of the weight loaded on the weight plate 9 increases or decreases, since the adjustable sensor pressure head 11 and the sensor metal contacts are in contact with each other, the deformation of the deflection-correcting spring steel sheet 8 will not change again, and no additional force will be provided. The supporting force, that is, the pressure carried by the sensor is still the weight of the weight. If the loaded weight is not at the center point of the weight plate 9, a rotational torque will be generated relatively, and this torque will be offset by the four parallel deflection-correcting spring steel sheets 8, so as to ensure that the weight plate 9 is always horizontal, so that the load in The resultant force on the miniature pressure sensor remains vertical all the time, so no matter where the weight is placed on the weight pan 9, it has no influence on the sensor.

Example:

Firstly, place the calibration table base 1 of the present invention on a flat ground or a desktop, adjust the base adjustment nut 13 with a spirit level, and calibrate the horizontal plane of the calibration table base 1 to ensure that the base 9 is in a horizontal state.

Then, install the micro pressure sensor to be calibrated on the sensor fixture 12 of the calibration table base 1, and adjust the position so that the stainless steel ball on the top of the micro sensor faces the adjustable sensor pressure head 11 above. Loosen the fixing bolt handle 4, and turn the screw knob 7 to adjust the height position of the seat 3 and the left bearing seat 10, so that the distance between the adjustable sensor pressure head 11 and the contact point of the micro sensor is about 0.5 cm, and the deflection correction spring steel sheet 8 In a naturally curved state.

Secondly, connect the sensor measurement circuit and observe the output signal value of the micro sensor, which is the output at no-load. Slowly adjust the screw knob 7 again to slowly lower the height of the bearing seat 10. When the adjustable sensor pressure head 11 just touches the metal contact point of the micro sensor, and once the screw knob 7 is turned again, the value of the circuit output signal changes immediately. Lock the fixing bolt handle 4. At this time, it is the critical state of no weight loaded, that is, the state where the force is zero. Check each spare part in the device to ensure that each spare part is installed accurately and securely, and the micro pressure sensor calibration device is adjusted.

Finally, add weights of the same accuracy level at fixed intervals to the weight plate in sequence, and record the signal output of the pressure sensor circuit at different weight moments; after reaching the range, reduce the weights to zero in turn. According to the principle of sensor calibration, the calibration curve is fitted after repeated measurements to complete the calibration work of the sensor.

During the processing and assembly of the micro pressure sensor calibration device, it is necessary to ensure the level of the calibration table base 1 of the sensor, the verticality of the calibration table base 1 and the fixed shaft 2 of the wire, and the verticality of the guide fixed shaft 2 and the adjustment seat 3 , it is also necessary to ensure that the lengths of the four deviation-correcting spring steel sheets 8 are consistent, and the quenched deviation-correcting spring steel sheets need to have the same hardness. The micro pressure sensor calibration device ensures the accuracy of the position and direction of the loading force point during calibration through mechanical design, processing and installation accuracy, and the anti-eccentric load capacity of the correction spring steel sheet 8, so as to realize accurate transmission of force and improve calibration accuracy.

Claims (4)

1. A calibration device for a miniature pressure sensor, comprising a calibration device base (1), a bearing seat (10), a loading plate (9), a guide fixed shaft (2), an adjustment seat (3) and a sensor pressure head (11 ), the described guiding and fixing shaft (2) is arranged on the bearing seat (10), and the described adjusting seat (3) is arranged on the guiding and fixing shaft (2) and can move up and down along the described fixing shaft (2) , the loading disc (9) is arranged on the upper end of the bearing seat (10), and the sensor pressure head (11) is arranged on the lower end of the bearing seat (10), it is characterized in that: the bearing seat (10) Four deflection-correcting spring steel sheets (8) are used to connect with the adjustment seat (3). 2. The calibration device of the miniature pressure sensor according to claim 1, characterized in that: the adjustment seat (3) is also provided with an adjustment threaded hole and a locking threaded hole to fix the bolt handle (4), and A screw (5) is arranged in the pit, and the upper end of the screw is a screw knob (7); the threaded locking hole communicates with the guide fixing shaft hole, and is set in the locking threaded hole There is a set bolt handle (4). 3. The calibration device of the miniature pressure sensor according to claim 1, characterized in that: the sensor pressure head (11) is an adjustable sensor pressure head, and the adjustable pressure head and the bearing seat (10) threaded connection. 4. The calibration device for miniature pressure sensors according to claim 1, characterized in that: a sensor fixture (12) is also provided on the base (1) of the calibration device.

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