CN104034463A - High-linearity segmented-excitation type torque sensor - Google Patents

Abstract

A segmented excitation torque sensor with high linearity, which mainly includes a sensor shaft, an inner ring iron core, a first excitation winding, a compensation winding, an outer ring iron core, an output winding and a second excitation winding, the first excitation winding and compensation The windings are fixed in the inner ring iron core, the two-phase windings are orthogonal in space, the second excitation winding and the output winding are fixed in the outer ring iron core, the two-phase windings are also orthogonal in space, when the sensor is working, the two excitation windings Connected in series, input sinusoidal alternating voltage, when the sensor shaft is subjected to the load torque, the position of the second excitation winding and the output winding in space will change compared to the initial no-load torque, and through electromagnetic coupling, the output winding will generate The induced electromotive force corresponding to the load torque can make the induced electromotive force generated by the output winding and the load torque have a highly linear correspondence relationship by reasonably adjusting the number of turns of the two-stage excitation winding and the number of turns of the output winding.

Description

A High Linearity Segment Excitation Torque Sensor

technical field

The invention relates to a novel torque sensor, more specifically to a high linearity segmented excitation torque sensor based on the principle of magnetoelectric induction.

Background technique

With the continuous advancement of science and technology and the various needs of production development, torque measurement technology has been widely used in many fields such as industry, aerospace, agriculture, and military affairs. For example, in the intelligent measurement and control system of molded case low-voltage circuit breakers, the torque sensor is used to detect the output torque of the motor shaft in real time. When the screwdriver locks the nut to a certain degree, the torque increases instantaneously, and the magnetic torque sensor detects this stage jump signal to control the motor to stop.

At present, in torque measurement, transmission torque sensors are widely used. According to the generation mode of torque signals, transmission torque sensors can be divided into optical type, photoelectric type, magnetoelectric type, strain type, capacitive type, etc., among which the market is relatively mature. The current torque sensor is mainly magnetoelectric type and strain type. The essence of the output signal of the magnetoelectric torque sensor is two angular displacement signals with phase difference. The torque information is obtained after the signal is combined and processed. It is a non-contact sensor without wear and friction. It can be used for long-term measurement. It is large in size and difficult to install. It is produced by German HBM, Japan's Ono Shoki and China's Xiangxi Instrument Factory; strain-type torque sensors use resistance strain gauges as sensitive components, such as the T1, T2, and T4 series torque sensors of German HBM. Sensors, JN338 series sensors of Beijing Sanjing Group, etc., they install four precision resistance strain gauges on the rotating shaft or the elastic shaft connected in series with the rotating shaft, and connect them to form a Whiston bridge. The torque makes the small deformation of the shaft cause strain resistance When the value changes, the signal output by the bridge is proportional to the torque. The sensor can measure static and dynamic torque, high-frequency shock and vibration information. It has the advantages of small size and light weight. The disadvantage is that the transmission of the signal is susceptible to interference and loss Larger, the measurement accuracy is not very high.

Contents of the invention

The invention provides a new structure high linearity section excitation torque sensor, which mainly includes a sensor shaft, an inner ring iron core, a first section excitation winding, a compensation winding, an outer ring iron core, a second section excitation winding and an output winding. The first excitation winding and compensation winding are fixed in the inner ring iron core, and the two-phase windings are orthogonal in space. The second excitation winding and output winding are fixed in the outer ring iron core, and the two-phase windings are also orthogonal in space.

When the sensor is working, the two excitation windings are connected in series, and a sinusoidal alternating voltage is applied. When there is no load torque, the axis of the first excitation winding and the axis of the second excitation winding have the same position in space, and the axis of the compensation winding The position of the axis of the output winding is also the same in space. The pulsating magnetic flux generated by the excitation winding has no turn link with the output winding, and the induced electromotive force of the output winding is zero; when the sensor shaft is subjected to the load torque, the second excitation winding and The output winding is twisted through a certain space angle at the same time, and the initial position has changed relative to the action of no load torque. At this time, the pulsating magnetic flux generated by the excitation winding and the output winding turn chain are electromagnetically coupled, and the output winding generates a corresponding load torque. The induced electromotive force generated by the output winding can be made to have a highly linear relationship with the load torque by reasonably adjusting the number of turns of the two excitation windings and the number of turns of the output winding.

The purpose of the present invention takes the following technical solutions to achieve:

A segmented excitation torque sensor with high linearity, which mainly includes a sensor shaft, an inner ring core, a first excitation winding, a compensation winding, an outer ring core, an output winding, and a second excitation winding;

The left end of the inner ring core is fixed to the sensor shaft, and the right end of the inner ring core is in contact with the sensor shaft through a bearing and can rotate relative to the sensor shaft;

The right end of the outer ring core is fixed to the sensor shaft, and the left end of the outer ring core is in contact with the inner ring core through a bearing and can rotate relative to the inner ring core;

The inner ring core is provided with a winding slot, and the first section of the excitation winding and the compensation winding are embedded in the inner ring core winding slot, and the axis of the first section of the excitation winding and the axis of the compensation winding are perpendicular to each other in space;

The outer ring core is provided with a winding slot, the second field winding and the output winding are embedded in the outer ring core winding slot, and the axis of the second field winding and the axis of the output winding are perpendicular to each other in space;

When there is no load torque, the axis of the first excitation winding and the axis of the second excitation winding have the same position in space, and the axis of the compensation winding and the axis of the output winding have the same position in space.

The first excitation winding embedded in the inner ring core and the second excitation winding embedded in the outer ring core are connected in series, and a sinusoidal AC voltage is applied during operation:

The lead wires at both ends of the compensation winding embedded in the inner ring core are directly shorted;

The number of turns of the second excitation winding is the same as that of the output winding.

The ratio between the number of turns of the first stage excitation winding and the number of turns of the output winding is between 0.56-0.59.

As above-mentioned structure, novel high linearity subsection excitation type torque sensor of the present invention, its working principle is:

The first section of excitation winding and the second section of excitation winding are connected in series, and a sinusoidal AC voltage is applied to generate a pulse vibration magnetic field whose magnetic potential amplitude changes with time, forming a closed loop through the outer ring core, air gap and inner ring core. One end of the sensor shaft is fixed, and the other end is loaded with torque. When the load torque is zero, the sensor shaft does not deform, and the initial positions of the inner ring core and the outer ring core fixed at both ends of the sensor shaft remain unchanged, and are fixed on the inner ring core. The initial positions of the first section of excitation winding and the output winding fixed on the outer ring core are 90° in space, and the initial positions of the second section of excitation winding and output winding fixed on the outer ring core are different in space 90°, the axis of the first excitation winding is in the same spatial position as the axis of the second excitation winding, and the axis of the compensation winding is in the same spatial position as the axis of the output winding. At this time, the excitation magnetic field is a direct axis magnetic field , there is no interlinkage with the output winding, and the induced electromotive force generated by the output winding is zero; when the load torque is not zero, the sensor shaft is deformed, and the second excitation winding and the output winding are twisted through a certain space angle at the same time, relative to the initial position. Change, the excitation magnetic field generated by the excitation winding is interlinked with the output winding, and the output winding generates a corresponding induced electromotive force, which corresponds to the load torque loaded on the sensor shaft.

At this time, the second excitation winding rotates through a certain space angle relative to the initial position, and the pulsating magnetic flux generated by the second excitation winding has a quadrature axis component. Since the compensation winding is directly short-circuited, and the impedance of the compensation winding is very small, according to According to Lenz's law, the compensation winding generates a magnetic field against the quadrature-axis magnetic field to ensure that the magnetic field of the sensor is basically only the direct-axis magnetic field when it is working.

In order to make the induced electromotive force generated by the output winding of the sensor have a highly linear relationship with the load torque, the number of turns of the second excitation winding is the same as the number of turns of the output winding, and the ratio of the number of turns of the first excitation winding to the number of turns of the output winding It should be between 0.56-0.59.

As the above-mentioned structure, the present invention uses the principle of electromagnetic induction to form a new type of high linearity segmental excitation torque sensor. One end of the sensor shaft is fixed, and the other end is coaxially installed with the load, which can convert the load torque into an electrical signal output, and the output winding The resulting electrical signal is highly linear to the load torque.

Description of drawings

Fig. 1 is the structural representation of high linearity segmental excitation type torque sensor of the present invention;

Fig. 2 is the sectional view of A-A plane of Fig. 1;

Fig. 3 is the working principle figure that torque sensor of the present invention implements torque measurement;

FIG. 4 is a working schematic diagram of the compensation winding in FIG. 2 .

Detailed ways

The structural features of the torque sensor of the present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is a structural schematic diagram of a torque sensor of the present invention, including a sensor shaft 1, a bearing 2, an inner ring core 3, a first segment excitation winding winding 4, a compensation winding 5, an outer ring core 6, a second segment excitation winding 7, and an output winding 8 and bearing 9.

The left end of the inner ring iron core 3 is fixed to the sensor shaft 1 , and the right end of the inner ring iron core 3 is in contact with the sensor shaft 1 through the bearing 2 and can rotate relative to the sensor shaft 1 .

The right end of the outer ring core 6 is fixed to the sensor shaft 1 , and the left end of the outer ring core 6 is in contact with the inner ring core 3 through a bearing 9 and can rotate relative to the inner ring core 3 .

The inner ring core 3 is provided with a winding slot, and the first section of the excitation winding 4 and the compensation winding 5 are embedded in the winding slot of the inner ring core 3 .

The outer ring core 6 is provided with a winding slot, and the second section of the excitation winding 7 and the output winding 8 are embedded in the winding slot of the outer ring core 6 .

The first excitation winding 4 embedded in the inner ring core 3 and the second excitation winding 7 embedded in the outer ring core 6 are connected in series, and a sinusoidal AC voltage is applied during operation.

Lead wires at both ends of the compensation winding 5 embedded in the inner ring core 3 are directly shorted.

The number of turns of the second excitation winding 7 embedded in the outer ring core 6 is the same as the number of turns of the output winding 8 embedded in the outer ring core 6 .

The ratio between the number of turns of the first excitation winding 4 embedded in the inner ring core 3 and the number of turns of the output winding 8 embedded in the outer ring core 6 is between 0.56-0.59.

The material of the sensor shaft 1 is carbon steel or alloy steel; the inner ring core 3 and the outer ring core 6 are composed of high magnetic permeability iron-nickel soft magnetic alloy sheets or high magnetic permeability silicon steel sheets punched and laminated; the first section The excitation winding 4, the compensation winding 5, the second excitation winding 7 and the output winding 8 are all direct solderable polyurethane enamelled round copper wires.

Fig. 2 is a sectional view of A-A plane of Fig. 1, including the sensor shaft 1, the inner ring core 3, the first excitation winding winding 4, the compensation winding 5, the outer ring core 6, the second excitation winding 7 and the output winding 8.

The inner ring core 3 is provided with a winding slot, and the first section of the field winding 4 and the compensation winding 5 are embedded in the winding slot of the inner ring core 3, and the axis of the first section of the field winding 4 and the axis of the compensation winding 5 are perpendicular to each other in space.

The outer ring core 6 is provided with a winding slot, and the second section of the field winding 7 and the output winding 8 are embedded in the winding slot of the outer ring core 6, and the axis of the second section of the field winding 7 and the axis of the output winding 8 are perpendicular to each other in space .

When there is no load torque, the axis of the first field winding 4 and the axis of the second field winding 7 are in the same position in space, and the axis of the compensation winding 5 and the axis of the output winding 8 are in the same position in space.

The working principle of the high linearity sub-excitation torque sensor of the present invention to implement torque measurement is shown in Figure 3: the two ends of the first section of the excitation winding 4 are respectively _L1 and _L2 , and the first section of the excitation winding 4 uses _L1 -L ₂ , the two ends of the compensation winding 5 are respectively C ₁ and C ₂ , the compensation winding 5 is represented by C ₁ -C ₂ , and the two ends of the second excitation winding 7 are L ₃ and L ₄ respectively, , the second excitation winding 7 is represented by L ₁ -L ₂ , the two ends of the output winding 8 are respectively R ₁ and R ₂ , and the output winding 8 is represented by R ₁ -R ₂ .

After the first section of excitation winding L ₁ -L ₂ and the second section of excitation winding L ₃ -L ₄ are supplied with alternating current U _f , they generate pulsed magnetic flux Φ ₁ and pulsed magnetic flux Φ ₂ respectively, which pass through the inner ring core 3, The air gap and the outer ring core 6 form a closed magnetic circuit. When the sensor shaft is not affected by the load torque, the cross-sectional view of the sensor and the corresponding circuit wiring diagram are shown in Figure 3 (a), the pulse vibration flux Φ ₁ and the pulse vibration flux Φ ₂ are connected to the output winding R ₁ -R _2. The compensation winding C ₁ -C ₂ has no turn chain, the induced electromotive force e _o =0 generated by the output winding R ₁ -R ₂ , and the induced electromotive force e _c =0 generated by the compensation winding C ₁ -C ₂ , Figure 3(a) The magnetic flux Φ in is the composite magnetic flux of pulse vibration magnetic flux Φ ₁ and pulse vibration magnetic flux Φ ₂ .

When the sensor shaft is subjected to load torque, the cross-sectional view of the sensor and the corresponding circuit wiring diagram are shown in Figure 3(b), and the output windings R ₁ -R ₂ produce a corresponding angle counterclockwise relative to the initial position in Figure 3(a) Displacement θ, there is a one-to-one correspondence between the angular displacement θ and the applied load torque, the angle between the axis of the output winding R ₁ -R ₂ and the axis of the first section of the excitation winding L ₁ -L ₂ is 90-θ, then the output winding R The induced electromotive force e _o ≠0 generated by ₁ -R ₂ . In addition, the second section of excitation winding L ₃ -L ₄ also rotates counterclockwise through the angle θ, then the pulsating magnetic flux Φ ₂ generated by the second section of excitation winding L ₃ -L ₄ has a quadrature axis component, due to the compensation winding C ₁ - C ₂ is directly short-circuited, and the impedance of the compensation winding C ₁ -C ₂ is very small. According to Lenz's law, the magnetic flux generated by the induced current of the compensation winding C ₁ -C ₂ can basically drive the second segment of the excitation winding L ₃ -L The quadrature axis component of the _pulsating magnetic flux Φ generated by ₄ cancels out, so the magnetic flux when the sensor is working can be approximately considered as only the direct axis magnetic flux Φ.

According to the law of electromagnetic induction, the effective value E _L of the induced electromotive force generated in the first stage of the excitation winding L ₁ -L ₂ by the direct-axis pulsating magnetic flux Φ is:

E _L ＝4.44fW _f Φ (1)

In the formula, f is the frequency of the AC voltage U _f , and W _f is the number of turns of the first excitation winding L ₁ -L ₂ .

Similarly, the effective value E _m of the induced electromotive force generated by the direct-axis pulsating magnetic flux Φ in the second section of the excitation winding L ₃ -L ₄ is:

E _m ＝4.44fW _m Φcosθ＝kE _L cosθ (2)

In the formula, W _m is the number of turns of the second excitation winding L ₃ -L ₄ , k=W _f /W _m is the number of turns of the first excitation winding L ₁ -L ₂ and the second excitation winding L ₃ -L ₄ The ratio of the number of turns.

Assuming that the number of turns of the output winding is the same as W _m , the effective value E _o of the induced electromotive force generated by the direct-axis pulsating magnetic flux Φ in the output winding R ₁ -R ₂ is:

E _o ＝4.44fW _m Φcos(90-θ)＝kE _L sinθ (3)

Since the first section of excitation winding L ₁ -L ₂ and the second section of excitation winding L ₃ -L ₄ are connected in series, if the impedance of the two sections of excitation winding is ignored, according to Kirchhoff's voltage law:

U _f ＝E _L +E _m ＝E _L (1+kcosθ) (4)

Simultaneous formula (3) and formula (4) can get:

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; sin</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

It can be seen from formula (5) that there is a certain correspondence between the effective value E _o of the induced electromotive force generated by the output winding R ₁ -R ₂ and the angular displacement θ produced by the load torque, that is, there is a certain correspondence between E _o and the load torque.

The output characteristic of the sensor is preferably linear, that is, the ideal output characteristic is:

${\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; sin</span>}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; k</span>}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}}{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; KU</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}\mathrm{<span\; class="notranslate">\; \&theta;</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

The angular displacement θ generated by the load torque should be within the elastic range of the sensor shaft, and the degree is small, and at this time the load torque and the generated angular displacement θ have a linear relationship. In order to meet the requirements of formula (6), the ratio k=W _f /W _m between the number of turns of the first excitation winding L ₁ -L ₂ and the number of turns of the output winding R ₁ -R ₂ is deduced by the mathematical formula is between 0.56-0.59, when k=W _f /W _m =0.57, the maximum non-linear error obtained by torque sensor calibration is about 0.26%, which can meet the requirements of torque measurement in actual engineering.

The working principle of the compensation winding 5C ₁ -C ₂ in Fig. 2 of the torque sensor of the present invention is shown in Fig. 4: when the sensor shaft 1 is subjected to the load torque, the second section of the excitation winding L ₃ -L ₄ and the output winding R ₁ -R ₂ At the same time, the angle θ is rotated relative to the initial position, assuming that the excitation current of the first section of the excitation winding L ₁ -L ₂ and the second section of the excitation winding L ₃ -L ₄ is shown in Figure 4, the current flows in from the left end, and the right end flow out, the pulsating magnetic flux Φ ₂ generated by the second excitation winding L ₃ -L ₄ has a quadrature axis component Φ _sq , and according to Lenz's law, an induced current will be generated in the compensation winding C ₁ -C ₂ as shown in Figure 4 , the induced current generates magnetic flux Φ _c , which is used to offset the quadrature-axis component Φ _sq of the pulsating magnetic flux Φ ₂ generated by the second excitation winding L ₃ -L ₄ , so as to ensure that the magnetic flux of the sensor basically only has the direct axis Magnetic flux Φ.

Claims (10)

1. a high linearity segmentation excitation type torque sensor, mainly comprises sensor axis, interior ring iron core, first paragraph field winding, compensation winding, outer shroud iron core, output winding and second segment field winding.

2. torque sensor according to claim 1, is characterized in that: interior ring left end unshakable in one's determination and sensor axis are fixed, and right-hand member is contacted and can rotate relative to sensor axis with sensor axis by bearing.

3. torque sensor according to claim 1, is characterized in that: outer shroud right-hand member unshakable in one's determination and sensor axis are fixed, and left end contacts and can internally encircle mutually unshakable in one's determination rotation by bearing and interior ring iron core.

4. torque sensor according to claim 1, it is characterized in that: interior ring iron core is provided with slot for winding, first paragraph field winding and compensation winding embed in interior ring slot for winding unshakable in one's determination, and the axis of first paragraph field winding is spatially orthogonal with the axis of compensation winding.

5. torque sensor according to claim 1, it is characterized in that: outer shroud iron core is provided with slot for winding, second segment field winding and output winding embed in outer shroud slot for winding unshakable in one's determination, and the axis of second segment field winding is spatially orthogonal with the axis of output winding.

6. torque sensor according to claim 1, it is characterized in that: during non-loaded torsional interaction, spatially position is identical for the axis of the axis of first paragraph field winding and second segment field winding, and spatially position is identical with the axis of exporting winding for the axis of compensation winding.

7. torque sensor according to claim 1, is characterized in that: the first paragraph field winding embedding in interior ring iron core is that series system is connected with the second segment field winding embedding in outer shroud iron core, passes into sinusoidal voltage during work.

8. torque sensor according to claim 1, is characterized in that: the direct short circuit of two ends extension line that embeds the compensation winding in interior ring iron core.

9. torque sensor according to claim 1, is characterized in that: the number of turn that embeds the second segment field winding in outer shroud iron core is identical with the number of turn of output winding.

10. torque sensor according to claim 1, is characterized in that: embed the number of turn of the first paragraph field winding in interior ring iron core and the ratio that embeds between the number of turn of the output winding in outer shroud iron core is between 0.56-0.59.