CN201007719Y - Giant magnetic sensor and giant magnetic sensor speed measuring mechanism - Google Patents

Abstract

4 or 6 groups of giant magnetoresistances are fixed on the substrate of this giant magnetic sensor, and each group has 4 to 24 giant magnetoresistances. The other ends of the giant magnetoresistances in each group are connected to be output ends. The giant magnetic sensor speed measuring mechanism comprises the above-mentioned giant magnetic sensor, a magnetic drum, and a microprocessor circuit module. The rotating shaft of the magnetic drum is drivingly connected with the object to be measured. The giant magnetic sensor is fixed 0.05-0.15mm away from one side of the magnetic drum, and the giant magnetic sensor is connected to the microprocessor circuit module through the amplifying circuit. The magnetic drum rotates synchronously with the object to be measured, the magnetic field around it changes, and the resistance value of the giant magnetic sensor changes accordingly, and the signal is sent to the microprocessor to obtain the speed of the rotating moving object. The microprocessor automatically selects the subdivision magnification according to the signal frequency, which can adapt to the detection of different speeds from 1 to 5000 rpm, and the resolution is higher than 3.6×10 ^-5 radians, with strong anti-interference ability and high impact resistance, and can be used in harsh environments environment to work normally.

Description

Giant magnetic sensor and giant magnetic sensor speed measuring mechanism

(1) Technical field

The utility model relates to the technical field of speed measurement, in particular to a giant magnetic sensor and a non-contact rotational motion speed measurement mechanism made of the giant magnetic sensor.

(2) Technical background

Giant Magneto Resistive (Giant Magneto Resistive) is referred to as GMR for short. It is a high-tech product integrating magnetic thin film, semiconductor integration and nanotechnology. GMR has a large resistance effect under the action of a magnetic field. The magnetoresistance value of the alloy material is about ten times higher. Therefore, compared with photoelectric sensors, the sensor made of GMR has the advantages of high resolution, strong reliability, low-speed static detection, fast response, long detection distance, wide frequency bandwidth, small power consumption, small size, and can work in harsh environments. , has attracted people's attention in recent years, and GMR current sensors, GMR displacement sensors, etc. have come out. If the existing GMR displacement sensor is used for the rotating speed measuring mechanism, on the one hand, its resolution is not high enough, and the rotation direction cannot be distinguished in addition, so there is no suitable giant magnetic sensor dedicated to the rotating speed measuring mechanism at present.

In scientific research and production activities, it is often necessary to control and adjust the operating state of mechanical equipment. For this reason, various types of speed measuring mechanisms for rotational motion are required, such as tachometer generators, grating encoders, mechanical transmission pointer speed measuring instruments, magnetic Pulse or optical pulse speed tester, AMR magnetic encoder, etc. There are contact and non-contact types of these speed measuring devices, each with its own advantages and disadvantages. As far as the most commonly used tachogenerators, grating encoders, and AMR magnetic encoders are compared, the low-speed and high-speed characteristics of the tachogenerator are not good. The grating encoder overcomes the shortcomings of the tachogenerator, but it has poor weather resistance and is susceptible to moisture and mildew, thus affecting the accuracy. Anisotropic MagnetoResistive AMR (Anisotropic MagnetoResistive) magnetic encoders can work in harsh environments, but the fly in the ointment is that the resolution of AMR magnetic encoders is not high. At present, the magnetic sensors made of traditional AMR materials in the world have a magnetic field resolution index It is 40 microgauss, so the magnetic poles of the magnetic drum must not be too narrow, that is, under limited conditions, the number of magnetic pole pairs cannot be too much. In this way, under the same scale conditions, the number of pulses output by the AMR magnetic encoder is not as large as that of the grating encoder, that is, the accuracy is lower.

Compared with AMR materials, GMR materials have a larger change rate of magnetoresistance and higher sensitivity. Therefore, researchers are currently developing a high-precision and high-resolution giant magnetic speed measuring mechanism that uses giant magnetic sensors to meet the harsh environmental conditions.

(3) Contents of utility model

The purpose of this utility model is to design a giant magnetic sensor specially used in the rotating speed measuring mechanism, which has high resolution and can distinguish the direction of rotation.

Another purpose of the utility model is to design a giant magnetic velocity measuring mechanism using the giant magnetic sensor designed by the utility model, which is used for online synchronous tracking of the rotational speed of the detected object.

The giant magnetic sensor designed by the utility model includes an insulating substrate and a giant magnetoresistance, and N groups of giant magnetoresistance grid bars are fixed in parallel on the substrate plane, N=4 or 6, and each group has n bars with a length of 3mm to 5mm and a width of 0.015mm ~0.03mm giant magnetoresistance, n is an integer from 4 to 24, the center distance of grid bars is 0.1 mm to 0.5 mm, and the width of each group of grid bars is 2.5 mm to 10.0 mm. The resistance value of each giant magnetoresistance is 500Ω-1000Ω. Divide N groups of giant magnetoresistance grid strips into front and back two parts N ₁ and N ₂ , when there are 4 groups, the first and second groups are N ₁ part, the third and fourth groups are N ₂ parts, and when the 6 groups are 1, 2, 3 groups are part _N1 , the 4th, 5th and _6th groups are part N2; one end of each giant magnetoresistance grid bar of each group of part _N1 is connected to each other, which is the input terminal a of the sensor, and each part of _N2 part One end of each giant magnetoresistance grid strip in the group is connected to each other, which is the input terminal b of the sensor; each group of _N1 part is connected with the other end of each giant magnetoresistance grid strip of each group of _N2 part in turn, and then it is the input terminal b of the sensor. Output terminals; that is, when there are 4 groups, the first and second groups of the _N1 part are respectively connected with the other end of each giant magnetoresistance grid bar of the third and fourth groups of the _N2 part to be the sensor output A and output B, When there are 6 groups, the 1st, 2nd, and 3rd groups of the _N1 part are respectively connected with the other ends of the giant magnetoresistance grid strips of the 4th, 5th, and 6th groups of the _N2 part to form the sensor output terminals A, B, and C.

The input end of the sensor is connected to a DC power supply, and the output voltage of the output end is connected to an amplifying circuit. The giant magnetic sensor speed measuring mechanism designed by the utility model includes a giant magnetic sensor, a magnetic drum, and a microprocessor circuit module. The giant magnetic sensor is the aforementioned giant magnetic sensor of the utility model. 800 to 1600 pairs of magnetic poles are evenly distributed. The rotating shaft of the magnetic drum is driven and connected with the rotating shaft of the object to be measured through the magnetic coupling, and the rotating mechanical energy is transmitted to the magnetic drum through the magnetic coupling. The giant magnetic sensor is fixed on one side of the magnetic drum, and its giant magnetoresistance grid is parallel to the axis of the magnetic drum. The distance between the giant magnetic sensor and the surface of the magnetic drum is 0.05mm to 0.15mm. The giant magnetic sensor is connected with the amplifying circuit, and the amplifying circuit is connected with the microprocessor circuit module.

The specific steps of synchronously detecting the rotational speed of the giant magnetic sensor speed measuring mechanism of the present utility model are as follows:

(1) Signal acquisition. When the object to be measured rotates, the magnetic drum rotates synchronously, and the magnetic flux polarity of the magnetic field around the magnetic drum changes continuously. The change; when the rotation direction of the magnetic drum is different, the direction of the magnetic field change is different, and the phase sequence of the giant magnetoresistance of each group of giant magnetic sensors affected by the magnetic field is different, and the rotation direction can be determined accordingly.

(2) Signal conversion, the giant magnetoresistance converts the captured magnetic flux change pulse signal into an electric pulse signal and sends it to the amplifying circuit, which is amplified and shaped into a square wave pulse signal;

(3) signal processing, step (2) gained square wave pulse signal is transmitted to the microprocessor circuit module, output counting pulse, positive and negative state pulse and subdivision multiple pulse after the signal is digitized; Microprocessor circuit module After subdivision processing, the precise speed change of the rotating body can be obtained, up to 8000 subdivisions; in order to adapt to the detection of rotating moving bodies with wide speed changes, the microprocessor circuit module automatically to change the subdivision magnification. That is, when the frequency of the output signal is higher than the allowable output value of 20×10 ⁶ Hz, the subdivision magnification is automatically changed, which avoids the decrease of the frequency response due to the increase of the subdivision magnification, and realizes the intelligent detection of the speed change of the rotating body.

The giant magnetic sensor of the utility model has the advantages of high detection precision and strong reliability, and is especially suitable for use in a rotating speed measuring mechanism, and can determine the direction of rotation.

The advantages of the giant magnetic speed measuring mechanism of the utility model are: 1. The microprocessor circuit module automatically selects the subdivision magnification according to the level of the signal frequency, which can not only adapt to the speed detection of the ultra-low-speed rotary motion of only one revolution per minute, but also can adapt to each 5000 revolutions per minute, high-speed continuously changing rotational motion speed detection, and the resolution is higher than 3.6×10 ^-5 radians, which overcomes the inability of traditional grating encoders and AMR magnetic grating encoders to meet the speed detection of high and low speed moving objects with the same accuracy level Accuracy requirements; 2. Strong anti-interference ability, high impact resistance, and can work normally in harsh environments; 3. Small size, high cost performance, convenient installation and debugging, and practical.

(4) Description of drawings

Fig. 1 is the structural representation of embodiment of giant magnetic sensor of the present invention;

Fig. 2 is the circuit block diagram of the giant magnetic velocity measuring mechanism embodiment of the present invention;

Fig. 3 is a structural schematic diagram of an embodiment of the giant magnetic speed measuring mechanism of the present invention.

In the figure: 1. sealing ring, 2. base, 3. magnetic drum shaft, 4. fixed bracket, 5. giant magnetic sensor 6. amplifying circuit board, 7. shell, 8. microprocessor circuit board, 9. magnetic drum , 10.. Socket, 11. Magnetic Suspension Bearing, 12. Magnetic Coupling

(5) Specific implementation methods

The specific structure of the embodiment of the giant magnetic sensor of the utility model is shown in Figure 1, including an insulating substrate and a giant magnetoresistance, and 4 groups of giant magnetoresistance grid bars are fixed in parallel on the substrate plane, and each group has 4 bars with a length of 5.000mm and a width of 0.015mm. The giant magneto-resistance with a center distance of grid strips of 0.125mm has a width of 0.39mm in each group, and the total width of 4 groups is 2.5mm. The resistance value of each giant magnetoresistance is 500Ω, and the substrate is made of quartz glass or ceramic material. The first and second groups of giant magnetoresistance grid strips are part _N1 , the third and fourth groups are part _N2 , and one end of each giant magnetoresistance grid strips of the first and second groups of part _N1 is connected to each other, which is the sensor's Input end a, one end of each giant magnetoresistive grid bar of the 3rd and 4th groups of the _N2 part are connected to each other, which is the input end b of the sensor; the first group of the _N1 part and the third group of the _N2 part are each giant The other end of the magnetoresistance grid strip is connected to the sensor output terminal A, and the other end of each giant magnetoresistance grid strip of the second group of the _N1 part and the fourth group of the _N2 part is connected to the sensor output terminal B.

The circuit structure of the embodiment of the giant magnetic speed measuring mechanism of the utility model is shown in Figure 2, including a giant magnetic sensor, a magnetic drum, and a microprocessor circuit module. When the magnetic field changes, the giant magnetic sensor is connected to an amplifying circuit, and the amplifying circuit is connected to a microprocessor circuit module. Its giant magnetic sensor is the above-mentioned giant magnetic sensor of the utility model. The diameter of the magnetic drum is 32mm, and 800 pairs of magnetic poles are evenly distributed in a staggered manner on the circumference.

The giant magnetic speed measuring mechanism of the utility model is easy to use, and each component is assembled in the shell 6, as shown in Figure 3. A magnetic suspension bearing 11 is embedded on the base 2, and the magnetic drum rotating shaft 3 is vertically installed on the base 2 through the magnetic suspension bearing 11, supported by the base 2, and located at the bottom of the inner cavity of the casing 6. The magnetic suspension bearing 11 makes the magnetic drum 8 move at high speed without friction. The bottom end of the magnetic drum rotating shaft 3 is drivingly connected with the rotating shaft of the object to be measured through the magnetic coupling 12 located at the bottom of the base 2 . The bracket 4 is fixed on the base 2, the giant magnetic sensor 5 is fixed on the bracket 4, and is located on the side of the magnetic drum 8, and its giant magnetoresistance grid is parallel to the axis of the magnetic drum 8, and the gap between the giant magnetic sensor 5 and the surface of the magnetic drum 8 is 0.1mm. The circuit board of the amplifying circuit is mounted together with the giant magnetic sensor 5 , the output end of the amplifying circuit is connected to the input end of the microprocessor circuit module, and the circuit board 7 of the microprocessor circuit module is fixed on the inner cavity of the shell 6 and above the magnetic drum 8 . The microprocessor circuit module contains a voltage-controlled phase-locked loop circuit. When the output signal frequency of the microprocessor is higher than the allowable output value of 20×10 ⁶ Hz, the microprocessor sends a signal to the voltage-controlled phase-locked loop circuit to automatically change the subdivision ratio to keep the output signal frequency lower than 20×10 ⁶ Hz . After signal processing by the microprocessor circuit module, the counting pulse, forward and reverse state pulse and subdivision multiple pulse are output. The shell 6 is covered outside each component, and the bottom of the shell 6 is connected with the base 2 . There can be a straight bayonet between the shell 6 and the base 2, and the shell 6 can be connected by inserting the two down, which is convenient for loading and unloading. The output terminal of the microprocessor circuit module has a connector 9 to connect to the output socket 10, and the output socket 10 is fixed on one side of the shell 6, and the output signal can be drawn out with a matched plug. The output socket 9 is an aviation socket, which is connected with a matching aviation plug to ensure reliable and stable connection between the plug and the socket.

The magnetic intervening medium of the magnetic drum 8 is neodymium iron boron (NdFeB) material, and the residual magnetic induction is 0.5×10 ³ to 50×10 ³ Gauss. The maximum frequency of the counting pulse signal of the magnetic drum 8 for one rotation is 20×10 ⁶ Hz.

The microprocessor circuit module may adopt a complex programmable logic device, that is, a CPLD module.

There are fixing holes on the base 2, which can be fixedly connected with the end surface of the shell of the rotating object to be measured. The bottom surface of the base 2 is embedded with a sealing ring 1, and the base 2 is sealed and connected with the end surface of the shell of the measured object to prevent dust and oil from entering. In the shell 6 of this speed measuring mechanism.

When in use, connect the base 2 of the speed measuring mechanism with the end surface of the measured object shell, the magnetic coupling 12 transmits the mechanical energy of the measured object to the magnetic drum shaft 3, and the magnetic drum 8 rotates synchronously with the measured object. The magnetic field change pulse obtained by the magnetic sensor 5 is sent to the microprocessor circuit module after being processed by the amplifying circuit, and the secondary value of the output pulse signal voltage is up to 5V, and there are positive and negative pulse signals. 10 ⁶ Hz. The microprocessor tracks the speed of the measured object and automatically selects the subdivision magnification, which can adapt to the lowest speed of 1 revolution per minute, and can also be used in occasions with 5000 revolutions per minute, and the resolution is higher than 3.6×10 ^-5 radians. The speed measuring mechanism is mainly used to realize the precise measurement of the rotational speed on the automatic production line, and cooperates with the control mechanism.

The following table shows the speed measurement results of the speed measurement mechanism for different speeds.

Speed (rev/min) Resolution of speed measurement results (seconds) Average resolution value (seconds) error% first first first 1 1.67×10 ^-2 1.61×10 ^-2 1.65×10 ^-2 1.64×10 ^-2 1.23 10 1.62×10 ^-1 1.63×10 ^-1 1.61×10 ^-1 1.62×10 ^-1 0 200 1.62 1.61 1.63 1.62 0 1000 16.36 16.24 16.36 16.32 0.74 3000 16.16 16.12 16.24 16.17 0.19 5000 16.20 16.22 16.22 16.22 0.12

It can be seen from the table that in the case of low speed, that is, when the speed is only 1 rpm, the average resolution of the speed measuring mechanism reaches 1.64×10 ^-2 seconds; in the case of high speed, that is, when the speed reaches 5000 rpm, the The average resolution of the speed measuring mechanism reaches 16.22 seconds. The speed-measuring mechanism is suitable for a wide speed range, sensitive in response and high in precision.

Claims (10)

1. A giant magnetic sensor, comprising insulating substrate and giant magnetoresistance, is characterized in that: N groups of giant magnetoresistive grids are fixed in parallel on the substrate plane, N=4 or 6, and each group has n giant magnets with a length of 3mm to 5mm, a width of 0.015mm to 0.03mm, and a grid center distance of 0.1mm to 0.5mm. Resistance, n is an integer from 4 to 24, the width of each group of grid bars is 2.5 mm to 10.0 mm, and the resistance value of each giant magnetoresistance is 500Ω to 1000Ω; N groups of giant magnetoresistance grid bars are divided into front and rear parts N ₁ And _N2 , one end of each giant magnetoresistance grid bar of each group of _N1 part is connected with each other, is the input end A of this sensor, and one end of each giant magnetoresistance grid bar of each group of _N2 part is connected with each other, is this The input terminal B of the sensor; each group of the _N1 part is in turn connected with the other end of each giant magnetoresistance grid bar of each group of the _N2 part, and then it is the output terminal of the sensor; the input terminal of the sensor is connected to a DC power supply, and the output terminal output changes voltage. 2. A giant magnetic speed measuring mechanism, comprising giant magnetic sensor, magnetic drum, microprocessor circuit module, is characterized in that: The giant magnetic sensor is N groups of giant magnetoresistance grid bars fixed in parallel on the insulating substrate plane, N=4 or 6, each group has n bars with a length of 3 mm to 5 mm, a width of 0.015 mm to 0.03 mm, and a grid center distance of 0.1 mm～0.5mm giant magnetoresistance, n is an integer of 4～24, the width of each group of grid bars is 2.5mm～10.0mm, and the resistance value of each giant magnetoresistance is 500Ω～1000Ω; N groups of giant magnetoresistance grid bars It is divided into two parts N ₁ and N ₂ , one end of each giant magnetoresistance grid strip of each group of N ₁ part is connected to each other, which is the input terminal a of the sensor, and each giant magnetoresistance grid strip of each group of N ₂ part One end connected with each other is the input terminal b of the sensor; each group of the _N1 part is connected with the other end of each giant magnetoresistance grid bar of each group of the _N2 part in turn to be the output terminal of the sensor; the input terminal of the sensor is connected to DC power supply, the output voltage of the output terminal is connected to the amplifier circuit; The diameter of the magnetic drum is 28mm to 35mm, and 800 pairs to 1600 pairs of magnetic poles are evenly distributed radially staggered; the rotating shaft of the magnetic drum is driven and connected to the rotating shaft of the object to be measured through a magnetic suction coupling, and the giant magnetic sensor is fixed on one side of the magnetic drum , the giant magnetoresistance grid strips are parallel to the axis of the magnetic drum, and the distance between the giant magnetic sensor and the surface of the magnetic drum is 0.05 mm to 0.15 mm; the giant magnetic sensor is connected to an amplifying circuit, and the amplifying circuit is connected to a microprocessor circuit module. 3. The giant magnetic speed measuring mechanism according to claim 2, characterized in that: The microprocessor circuit module contains a voltage-controlled phase-locked loop circuit. When the output signal frequency of the microprocessor is higher than the allowable output value of 20×10 ⁶ Hz, the microprocessor sends a signal to the voltage-controlled phase-locked loop circuit, and automatically Change the subdivision ratio to keep the output signal frequency below 20×10 ⁶ Hz. 4. The giant magnetic velocity measuring mechanism according to claim 2, characterized in that: The giant magnetic sensor, amplifying circuit, magnetic drum, and microprocessor circuit module are assembled in the shell (6), the magnetic suspension bearing (11) is embedded on the base (2), and the magnetic suspension bearing (11) is mounted on the magnetic drum rotating shaft (3). Vertically installed on the base (2), supported by the base (2), at the bottom of the inner cavity of the housing (6), the bottom end of the magnetic drum rotating shaft (3) is connected to the magnetic coupling (12) at the bottom of the base (2) to be The rotating shaft of the measured object is driven and connected; the base (2) is fixed with the bracket (4), the giant magnetic sensor (5) is fixed on the bracket (4), and is located on the side of the magnetic drum (8). The magnetic sensor (5) is mounted as one, and the microprocessor circuit module circuit board (7) is fixed on the inner cavity of the casing (6) and above the magnetic drum (8); the casing (6) is covered outside each component, and the casing (6) The bottom is connected with the base (2). 5. The giant magnetic velocity measuring mechanism according to claim 2 or 3, characterized in that: The magnetic intervening medium of the magnetic drum (8) is NdFeB material, and the residual magnetic induction is 0.5×10 ³ to 50×10 ³ Gauss. 6. The giant magnetic velocity measuring mechanism according to claim 2, characterized in that: The microprocessor circuit module is a complex programmable logic device. 7. The giant magnetic velocity measuring mechanism according to claim 4, characterized in that: There is an in-line bayonet between the shell (6) and the base (2). 8. The giant magnetic velocity measuring mechanism according to claim 4, characterized in that: The output end of the microprocessor circuit module has a connector (9) connected to an output socket (10), and the output socket (10) is fixed on one side of the shell (6). 9. The giant magnetic velocity measuring mechanism according to claim 8, characterized in that: The output socket (10) is an aviation socket. 10. The giant magnetic velocity measuring mechanism according to claim 4, characterized in that: The base (2) has a fixing hole, the bottom surface is embedded with a sealing ring (1), and the base (2) is fixedly connected with the shell end surface of the rotating object to be measured.

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