CN201476912U - Dynamic torque non-contact measuring device based on radio frequency data transmission - Google Patents

Abstract

The utility model discloses a dynamic torque non-contact measuring device based on radio frequency data transmission. It solves the problems of the original dynamic torque measurement device such as large error, high cost, inconvenient use, and poor anti-interference ability. It has the advantages of simple structure, convenient use, low cost, and high measurement accuracy. It does not have contact for signal transmission wear, so it has a longer service life than the dynamic torque measuring device of the conductive slip ring type. Its structure is as follows: it is composed of a mechanical device installed on the measured shaft and a measuring circuit. The mechanical device includes a base, which is connected to the casing. There is a shaft sleeve on the shaft sleeve, and an annular circuit board is installed on the shaft sleeve; the measurement circuit is composed of a lower computer and an upper computer, wherein the lower computer is installed on the annular circuit board to complete the measurement and transmission of dynamic torque signals; the upper computer communicates with the lower computer wirelessly, Display, record and analyze the received information.

Description

Dynamic torque non-contact measuring device based on radio frequency data transmission

technical field

The utility model relates to a dynamic torque measuring device, in particular to a dynamic torque non-contact measuring device based on radio frequency data transmission.

Background technique

Dynamic torque is the basic load form of various working transmission shafts, an important indicator of the power output of rotating machinery, one of the signs to check whether the product is qualified, and a necessary parameter to calculate the mechanical power and efficiency. The measurement of dynamic torque is of great significance to the determination and control of the transmission shaft load, the strength design of the working parts of the transmission system and the selection of the prime mover capacity.

The dynamic torque measurement device is generally based on the principle of resistance strain, and uses a strain bridge to convert the dynamic torque of the rotating shaft into a voltage signal. Since the strain bridge is pasted on the rotating shaft, the power supply to the bridge and the output signal from the bridge have traditionally relied on conductive slip rings. The brush and the slip ring are easy to wear, and it is easy to cause the change of the contact resistance, which will cause noise interference and zero drift, resulting in large measurement errors. Therefore, the working life is short and it is not suitable for high-speed rotation and large vibration of the shaft. At present, resolvers are often used for power supply and signal transmission. The resolver core is fragile and the maximum rotational speed is still limited. Alignment of the transformer primary and secondary introduces noise and errors that affect measurement accuracy. Resolvers require dedicated signal conditioning circuitry in order to generate a signal that can be received by a particular data acquisition device, further adding to the cost of the measurement. Infrared ray transceiver technology adopts point-to-point connection mode, which is directional. The disadvantage of this technology is that it is limited to the communication between two devices and cannot form a network flexibly. Moreover, when infrared technology transmits data, there must be no obstacles between the devices, and the effective distance is small. It is inconvenient to use infrared transmission method for dynamic torque measurement and has certain limitations in application occasions.

Contents of the invention

The purpose of this utility model is to solve the problems of the original dynamic torque measuring device, such as large error, high cost, inconvenient use, poor anti-interference ability, etc., and provide a device with the advantages of simple structure, convenient use, low cost, and high measurement accuracy. A non-contact measuring device for dynamic torque based on radio frequency data transmission. The device uses radio frequency technology to realize non-contact transmission of dynamic torque signals, and has simple structure, convenient use, small error and low cost. During the online measurement of dynamic torque, the device does not have contact wear in signal transmission, so it has a longer service life than the conductive slip ring type dynamic torque measurement device.

In order to achieve the above object, the utility model adopts the following technical solutions:

A dynamic torque non-contact measuring device based on radio frequency data transmission, which consists of a mechanical device installed on the measured shaft and a measurement circuit. The mechanical device includes a base, which is connected to the casing and installed in the casing The elastic shaft and the corresponding bearing device are equipped with a shaft sleeve on the elastic shaft, and an annular circuit board is installed on the shaft sleeve; the measurement circuit is composed of a lower computer and an upper computer, and the lower computer is installed on the annular circuit board to complete the dynamic torque signal. Measurement and emission; the upper computer communicates wirelessly with the lower computer, and displays, records, analyzes and processes the received information.

The bearing device includes a deep groove ball bearing, the deep groove ball bearing is assembled with the bearing end cover, and the bearing end cover is assembled with the end cover.

The lower computer includes a resistance strain bridge, the two ends of the resistance strain bridge are connected to the DC/DC chip, and the DC/DC chip is connected to the lithium battery; the remaining two ends of the resistance strain bridge are connected to the amplifier, and the amplifier is sequentially A filter, an analog-to-digital converter, and a single-chip microcomputer 1 are connected in series, and the single-chip microcomputer 1 is connected with the radio frequency transceiver circuit 1.

The host computer includes a radio frequency transceiver circuit II, which is connected with the single-chip microcomputer II, and the single-chip microcomputer II is connected with the printer and the keyboard display circuit respectively, and the single-chip microcomputer is also provided with a USB interface and an RS232 interface.

The utility model is a dynamic torque non-contact measuring device based on radio frequency data transmission, which is composed of two parts: a mechanical structure and a circuit. The mechanical structure is composed of a base, a casing, an elastic shaft, bearings, bushings, screws, etc. The circuit includes a lower computer and an upper computer. The lower computer completes the measurement and transmission of the dynamic torque signal. The upper computer completes the receiving, displaying, recording, analyzing and processing of the dynamic torque signal. The lower computer is composed of a resistance strain bridge, an amplifier, a filter, a single-chip microcomputer I, a radio frequency transceiver circuit I, and the like. The upper computer is composed of radio frequency transceiver circuit II, single chip microcomputer II, keyboard display circuit and USB, RS-232 and other communication interfaces.

Measuring principle of the present utility model:

Based on the principle of resistance strain, the dynamic torque signal is converted into a voltage signal, and the voltage signal is amplified for A/D conversion. Finally, the single-chip microcomputer I controls the radio frequency transceiver circuit I to transmit the converted measurement signal to the radio frequency transceiver circuit II for display and recording and analysis processing.

Each main component of the utility model introduces its working principle as follows:

1. Resistive strain bridge

When the rotating shaft is subjected to dynamic torque, there is a slight torsional deformation. Resistive strain gauges are common sensing elements for measuring tiny strains, and can be used to measure parameters such as dynamic torque. Paste the strain gauge on the elastic element or the surface of the object that needs to measure deformation with special glue. Under the action of dynamic torque, the strain gauge deforms together with the elastic element, and its resistance value changes accordingly. Thereby, dynamic torque changes are converted into resistance changes. It has the advantages of small size, fast dynamic response, high measurement accuracy and convenient use.

The resistance strain bridge is a measurement circuit that converts the change of resistance into voltage or current output. Its output can be directly measured by an indicating instrument, or sent to an amplifier for amplification. The bridge measurement circuit is simple, and has high accuracy and sensitivity, and is widely used in measurement devices. In the test technology, the bridge is generally divided into half-bridge and full-bridge connections according to the number of bridge arms whose resistance value participates in the change during work. The bridge connection method is different, for the same deformation input, the output voltage is also different, the full bridge connection method can obtain the maximum output. In order to improve the measurement accuracy, the utility model adopts the full bridge connection mode.

2. Signal Amplifier

Since the voltage and current output by the strain resistance bridge have relatively small changes, they usually need to be conditioned before being converted into digital quantities. The conditioning circuit makes the measurement signal suitable for the input range of the analog-to-digital converter (ADC) by amplifying, filtering, and adjusting the amplitude of the analog signal, and then the ADC digitizes the signal and sends it to a microprocessor or other digital devices, and then Complete further data processing.

When the dynamic torque measuring device is loaded positively and negatively, the output of the strain bridge is a bipolar signal. Applying a bipolar signal to a single-supply ADC is often difficult because it requires converting the bipolar signal to the ADC's allowed unipolar input range. The utility model adopts a simple and convenient method for realizing this conversion. In order to prevent the output reverse voltage signal from being "eaten" by the ground terminal of the amplifier, the reference terminal voltage of the amplifier is increased. In this way, when the dynamic torque is reversely loaded to the maximum, the amplifier outputs the minimum value of the forward voltage signal; when the dynamic torque is loaded to the maximum, the amplifier outputs the maximum value of the forward voltage signal.

3. SCM control circuit

In the utility model, two single-chip microcomputers are its core parts. On the one hand, it needs to receive the dynamic torque measurement data after A/D conversion, and on the other hand, it also needs to process the measurement data and control the radio frequency transceiver circuit to transmit the processing results to the radio frequency receiving device. When working, the single-chip microcomputer is powered by a battery and rotates together with the rotating shaft. Therefore, the two single-chip microcomputers adopted in the utility model need to have characteristics such as low power consumption, fast speed, and strong stability. ADC is the core component of the analog input channel, which converts the analog voltage signal into a digital quantity that can be processed by the single-chip microcomputer. The dynamic torque measurement device requires high measurement accuracy, so a high-precision ADC is required. The circuit of the lower computer of the utility model is concentrated on the ring circuit board. The annular circuit board is axially fixed on the elastic shaft. In order to save space on the circuit board, the utility model adopts an internally integrated high-precision ADC, which is suitable for a single-chip microcomputer powered by a battery and meets the requirements of small size and convenient use.

Four, two radio frequency transceiver circuits

The dynamic torque measurement signal is transmitted to the radio frequency receiving device through radio frequency transmission, thereby realizing the non-contact measurement of the dynamic torque. Radio frequency transmission is a critical part of a dynamic torque measurement setup. Since measurement data is to be transmitted in real time in a dynamic state, a very stable and reliable radio frequency transmission unit is required.

Radio frequency transmission generally uses a single-chip radio frequency transceiver chip, plus a controller and a small number of peripheral devices to form a dedicated or general wireless communication module. The communication module generally includes a simple and transparent data transmission protocol or uses a simple encryption protocol. Users do not need to have a deep understanding of the principle and working mechanism of wireless communication, as long as they operate according to the command word, the basic wireless transmission function can be realized. Its power is small, and its development is simple and fast. The dynamic torque non-contact measuring device based on radio frequency data transmission has the advantages of easy realization and convenient use.

Description of drawings

Figure 1 is a schematic diagram of device installation;

Fig. 2 is a device diagram of the mechanical structure diagram of the device;

Figure 3 is the principle frame of the lower computer;

Figure 4 is a block diagram of the upper computer of the device.

Among them, 1 base, 2 end cover, 3 bearing end cover, 4 deep groove ball bearing, 5 elastic shaft, 6 slotted countersunk head screw, 7 hexagon socket head cap screw, 8 washer, 9 shaft sleeve, 10 ring circuit board, 11 case, 12 lithium battery, 13DC/DC chip, 14 strain resistance bridge, 15 amplifier, 16 filter, 17 analog-to-digital converter, 18 single chip I, 19 radio frequency transceiver circuit I, 20 single chip microcomputer II, 21 radio frequency transceiver circuit II, 22 printers, 23USB interface, 24 keyboard display circuit, 25RS232 interface.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

In Fig. 1, the utility model is mainly composed of a mechanical device and a measuring circuit, wherein the mechanical device is connected with the measured motor and the load (magnetic powder brake) through a coupling. The measurement circuit includes an upper computer and a lower computer. The lower computer is installed on a mechanical device to collect measurement signals. The upper computer receives radio frequency signals containing dynamic torque information for display, recording and analysis.

Fig. 2 is a structural schematic diagram of the mechanical device. It includes a base 1, the base 1 is connected with the casing 11, an end cover 2 is provided at the end of the base 1 and the casing 11, the bearing end cover 3 is assembled with the end cover 2 through the slotted countersunk head screw 6, and the bearing end cover 3 is assembled with the deep groove ball bearing 4, and the elastic shaft 5 is assembled on the deep groove ball bearing 4. The end cover 2 is connected with the casing 11 through the hexagon socket cap screw 7 . The elastic shaft 5 is connected to the shaft sleeve 9 through the hexagon socket head cap screw 7 , and the annular circuit board 10 is connected to the shaft sleeve 9 through the slotted countersunk screw 6 and the washer 8 . The upper computer is installed on the ring circuit board 10 .

Fig. 3 is a structural diagram of the lower computer, which includes a strain resistance bridge 14, the two ends of the strain resistance bridge 14 are connected to a DC/DC chip 13, and the DC/DC chip 13 is connected to a lithium battery 12. The remaining two ends of the strain resistance bridge 14 are connected with the amplifier 15, the filter 16, the analog-to-digital converter 17, the single-chip microcomputer 118 and the radio frequency transceiver circuit 1 in sequence.

The measurement and transmission circuit of the lower computer adopts a strain bridge connected by a full bridge to sense the torsional strain of the rotating shaft. When the dynamic torque is loaded on the elastic shaft, the bridge outputs a dynamic voltage signal. The power supply components composed of lithium batteries and DC/DC chips provide power to the lower computer. The bridge output signal is directly connected to the instrumentation amplifier. It is optimized for single power supply design, low power consumption, suitable for battery power supply. A forward bias voltage is added to the reference voltage terminal of the amplifier to shift the output voltage of the amplifier to the forward voltage range. In this way, the unipolar voltage signal output by the bridge is converted into a bipolar voltage signal. This just satisfies the input range of the integrated ADC in the single-chip microcomputer. After A/D conversion, the voltage signal output by the amplifier is transmitted by the single-chip microcomputer to control the radio frequency transceiver circuit.

The resistance strain bridge is pasted in the middle of the elastic shaft and processed into a rectangular area with a small cross-sectional area. The measuring and transmitting circuits are concentrated on the 17-ring circuit board. The elastic shaft of the mechanical structure is processed with a keyway, which can be connected with the tested motor and load through a coupling. The middle of the elastic shaft is processed into a rectangular area with a small cross-sectional area. On the one hand, it increases the elastic deformation, and on the other hand, it also makes the strain bridge easy to paste. The shaft sleeve with radial counterbore is fixed through the radially machined screw hole on the shaft. A threaded through hole is axially machined on the side of the sleeve to fix the ring circuit board. The circuit board that rotates with the shaft is designed in a ring shape, which can make full use of the internal space of the casing, and at the same time prevent the problem of eccentricity caused by centrifugal force.

Fig. 4 is the structural diagram of the upper computer, which includes the radio frequency transceiver circuit II21, the radio frequency transceiver circuit II21 is connected with the single-chip microcomputer II20, and the single-chip microcomputer II20 is connected with the printer 22, the keyboard display circuit 24, the USB interface and the RS232 interface respectively.

The host computer mainly completes signal receiving, displaying, recording, analysis and processing. The radio frequency receiving circuit sends the received dynamic torque measurement signal to the single chip microcomputer for calculation and processing, and converts it into the corresponding torque value. The single-chip microcomputer expands the keyboard display interface to enhance the human-computer interaction function. The measurement data can be printed out by extending the printer interface. It can also be connected to a computer through communication interfaces such as USB and RS-232.

Claims (4)

1. dynamic torque non-cpntact measurement device based on rf data transmission, it is characterized in that, it is made up of mechanical hook-up and metering circuit two parts of being installed on the measured axis, wherein mechanical hook-up comprises base, base is connected with casing, elastic shaft and corresponding bearing arrangement are installed in casing, on elastic shaft, are provided with axle sleeve, annular circuit board is installed on the axle sleeve; Metering circuit is made up of slave computer and host computer, and wherein slave computer is installed in annular circuit board, finishes the measurement emission of dynamic torque signal; Host computer and slave computer radio communication are to information demonstration, record and the analyzing and processing that receives.

2. the dynamic torque non-cpntact measurement device based on the rf data transmission as claimed in claim 1 is characterized in that described bearing arrangement comprises deep groove ball bearing, deep groove ball bearing and bearing (ball) cover assembling, bearing (ball) cover and end cap assembling.

3. the dynamic torque non-cpntact measurement device based on the rf data transmission as claimed in claim 1 is characterized in that described slave computer comprises the resistance-strain electric bridge, and resistance-strain electric bridge two ends are connected with the DC/DC chip, and the DC/DC chip connects and is connected with lithium battery; The residue two ends of resistance-strain electric bridge are connected with amplifier, and amplifier is concatenated filter, analog to digital converter, single-chip microcomputer I successively, and single-chip microcomputer I is connected with RF transmit-receive circuit I.

4. the dynamic torque non-cpntact measurement device based on the rf data transmission as claimed in claim 1, it is characterized in that, described host computer comprises RF transmit-receive circuit II, it is connected with single-chip microcomputer II, single-chip microcomputer II then is connected with keyboard-display circuit with printer respectively, and he can thigh be that single-chip microcomputer also is provided with USB interface and RS232 interface.

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